Screening of Fracture Risk and Osteoporosis Among Older Long-term Care Residents: A Prospective Study

This prospective study assessed the effectiveness of screening older long-term care residents (LTCRs) for fracture risk and osteoporosis in Taiwan. Fracture risk screening was done using the Fracture Risk Assessment Tool (FRAX), and those with high or moderate risk were offered osteoporosis workup and treatment at the hospital. Among 785 LTCRs screened, 338 men (mean age 75.6) and 447 women (mean age 81.2) were included. Only 5.2% of women and no men were using anti-osteoporosis medication. Based on the Bone Health and Osteoporosis Foundation (BHOF) recommendations, 69.2% of men and 92.6% of women were classified as high fracture risk. In 110 participants willing to receive bone mineral density examination, osteoporosis was diagnosed in 86.2% of women and half of men. FRAX could effectively differentiate fracture risk in 648 LTCRs who completed 2-year follow-ups; no fracture occurred in the low-risk group. The study emphasizes the importance of fracture risk screening to enhance osteoporosis diagnosis and treatment among LTCRs.

Glutaredoxins regulate maize inflorescence meristem development via redox control of TGA transcriptional activity

Glutaredoxins (GRXs) are small oxidoreductases that can modify target protein activities through control of the redox (reduction/oxidation) state by reducing or glutathionylating disulfide bridges. Although CC-type GRXs are plant specific and play important roles in many processes, the mechanisms by which they modulate the activity of target proteins in vivo are unknown. In this study, we show that a maize CC-type GRX, MALE STERILE CONVERTED ANTHER1 (MSCA1), acts redundantly with two paralogues, ZmGRX2 and ZmGRX5, to modify the redox state and the activity of its putative target, the TGA transcription factor FASCIATED EAR4 (FEA4) that acts as a negative regulator of inflorescence meristem development. We used CRISPR-Cas9 to create a GRX triple knockout, resulting in severe suppression of meristem, ear and tassel growth and reduced plant height. We further show that GRXs regulate the redox state, DNA accessibility and transcriptional activities of FEA4, which acts downstream of MSCA1 and its paralogues to control inflorescence development. Our findings reveal the function of GRXs in meristem development, and also provide direct evidence for GRX-mediated redox modification of target proteins in plants.

One-year outcomes of an osteoporosis liaison services program initiated within a healthcare system

Due to the huge gap in the care of patients with osteoporosis and fragility fractures, we aimed to explore the effectiveness of the osteoporosis liaison service (OLS) in osteoporosis care. We found that OLS can improve osteoporosis care, including increasing medication compliance, increasing calcium/vitamin D/protein intake, and reducing fall rate.

INTRODUCTION

A significant gap exists in the care of patients with osteoporosis and fragility fractures. This study aimed to evaluate 1-year outcomes of an osteoporosis liaison service (OLS) program that includes two independent components: medication management services (MMS) to improve medication adherence and fracture liaison services (FLS) for secondary prevention.

METHODS

Patients with new hip fracture or untreated vertebral fractures enrolled in the FLS program (n = 600), and those with osteoporosis medication management issues but not necessarily fragility fractures enrolled in the MMS program (n = 499) were included. To evaluate outcomes, care coordinators assessed baseline items adapted from the 13 Best Practices Framework (BPF) standards of the International Osteoporosis Foundation, with telephone follow-up every 4 months for 1 year.

RESULTS

Mean age of this cohort was 76.2 ± 10.3 years, 78.8% were female. After 1-year participation in the program, all patients had received bone mineral density tests, and medication adherence for the entire cohort at 12 months was 91.9 ± 19.6%, with significant improvement in fall rates (23.4% reduction), exercise rates (16.8% increase), calcium intake (26.5% increase), vitamin D intake (26.4% increase), and adequate protein intake (17.3% increase) (all p < 0.05). After 1-year OLS program, the overall rates of mortality, incident fracture, and falls were 6.6%, 4.0%, and 24.3%, respectively.

CONCLUSIONS

The OLS program is associated with improved osteoporosis care, including increased medication adherence, calcium/vitamin D and protein intake, and reduced fall rate.

MiR-146 regulates the repair and regeneration of intervertebral nucleus pulposus cells via Notch1 pathway

OBJECTIVE

The aim of this study was to investigate the effects of regulation of micro-ribonucleic acid (miR)-146 expression targeting the Notch1 pathway on the repair and regeneration of intervertebral nucleus pulposus cells, and to explore the possible underlying mechanism.

MATERIALS AND METHODS

Intervertebral nucleus pulposus cells were harvested from rats and cultured in vitro. All cells were randomly divided into 4 groups, including the normal group, the miR-146 inhibitor group, the miR-146 over-expression group and the negative control group. The cells in the normal group were cultured normally. Meanwhile, the cells in the miR-146 inhibitor group and miR-146 over-expression group were transfected with inhibitor-containing plasmid and miR-146-containing plasmid, respectively. However, the cells in the negative control group were transfected with empty plasmid. 24 h after transfection, the cells were collected for subsequent experiments. The differentiation of nucleus pulposus cells was detected via toluidine blue staining. The relative protein expression levels of Notch1, aggrecan (ACAN) and COL II were detected via Western blotting. Meanwhile, the mRNA expressions of miR-146 and Notch1 were detected via quantitative Polymerase Chain Reaction (qPCR). Furthermore, the apoptosis and proliferation of cells were detected via terminal deoxynucleotidyl transferase-mediated dUTP Nick End Labeling (TUNEL) and Cell Counting Kit-8 (CCK-8; Dojindo, Kumamoto, Japan) assay, respectively.

RESULTS

Compared with the normal group, toluidine blue positive staining was significantly increased in miR-146 overexpression group (p<0.05), whereas was significantly decreased in the miR-146 inhibitor group (p<0.05). The results of Western blotting revealed that compared with normal group, the protein expression of Notch1 was markedly decreased in miR-146 over-expression group (p<0.05), whereas the expression levels of ACAN and COL II were notably increased (p<0.05). However, the miR-146 inhibitor group exhibited significantly increased the protein expression level of Notch1 (p<0.05), as well as markedly decreased the expressions of ACAN and COL II (p<0.05). The results of qPCR showed that compared with the normal group, the expression level of miR-146 was significantly increased in the miR-146 over-expression group. However, the mRNA expression level of Notch1 was remarkably decreased (p<0.05). Similarly, the miR-146 inhibitor group exhibited significantly decreased expression level of miR-146, as well as markedly increased mRNA expression level of Notch1 (p<0.05). Compared with those in the normal group, the cell proliferation rate was markedly increased, whereas cell apoptosis was remarkably decreased (p<0.05) in the miR-146 over-expression group. Furthermore, the cell proliferation rate was significantly decreased, while the cell apoptosis was remarkably increased (p<0.05) in the miR-146 inhibitor group.

CONCLUSIONS

Regulating miR-146 expression can target the Notch1 signaling pathway, thereby exerting important influences on the repair and regeneration of intervertebral nucleus pulposus cells.

[Study on antimicrobial susceptibility of Brucella in a city]

Objective: To investigate the antimicrobial susceptibility of Brucella and to provide a scientific basis for rational drug use and effective treatment of patients with brucellosis. Methods: A total of 41 Brucella strains were isolated from the blood of patients with brucellosis in 5 counties and 2 districts in Yuxi City, China from 2014 to 2016. The susceptibility to 23 antimicrobial drugs was tested using Kirby-Bauer (K-B) disk diffusion method and the sizes of antimicrobial rings were recorded. The susceptibility testing results were interpreted according to the Drug Susceptibility Testing Guideline (2009 version) . Results: The susceptibility rate of Brucella was 100.00% to ofloxacin, ciprofloxacin, levofloxacin, and amikacin and >90% to cefotaxime, cefepime, imipenem, doxycycline, cefoperazone, minocycline, tobramycin, rifampicin, cefoperazone/sulbactam, and chloramphenicol. The high resistance to aztreonam and ampicillin was observed (87.80% and 41.46%). Doxycycline-intermediate strains, rifampicin-intermediate strains, and rifampicin-resistant strains were identified. Conclusion: Doxycycline and rifampicin are commonly used in the treatment of brucellosis, but doxycycline/rifampicin-intermediate and-resistant strains have been identified. The susceptibility of Brucella to fluoroquinolones and cephalosporins was high, so the two drugs can be considered in the treatment of brucellosis.

Economic impact and cost-effectiveness of fracture liaison services: a systematic review of the literature

Fracture liaison services (FLS), implemented in different ways and countries, are reported to be a cost-effective or even a cost-saving secondary fracture prevention strategy. This presumed favorable cost-benefit relationship is encouraging and lends support to expanded implementation of FLS per International Osteoporosis Foundation Best Practice Standards. This study summarizes the economic impact and cost-effectiveness of FLS implemented to reduce subsequent fractures in individuals with osteoporosis. This systematic review identified studies reporting economic outcomes for FLS in osteoporotic patients aged 50 and older through a comprehensive search of MEDLINE, EMBASE, Cochrane Central, and PubMed of studies published January, 2000 to December, 2016. Grey literature (e.g., Google scholar, conference abstracts/posters) were also hand searched through February 2017. Two independent reviewers screened titles and abstracts and conducted full-text review on qualified articles. All disagreements were resolved by discussion between reviewers to reach consensus or by a third reviewer. In total, 23 qualified studies that evaluated the economic aspects of FLS were included: 16 cost-effectiveness studies, 2 cost-benefit analyses, and 5 studies of cost savings. Patient populations varied (prior fragility fracture, non-vertebral fracture, hip fracture, wrist fracture), and FLS strategies ranged from mail-based interventions to comprehensive nurse/physician-coordinated programs. Cost-effectiveness studies were conducted in Canada, Australia, USA, UK, Japan, Taiwan, and Sweden. FLS was cost-effective in comparisons with usual care or no treatment, regardless of the program intensity or the country in which the FLS was implemented (cost/QALY from $3023-$28,800 US dollars (USD) in Japan to $14,513-$112,877 USD in USA. Several studies documented cost savings. FLS, implemented in different ways and countries, are reported to be cost-effective or even cost-saving. This presumed favorable cost-benefit relationship is encouraging and lends support to expanded implementation of FLS per International Osteoporosis Foundation Best Practice Standards.

[An outbreak of paratyphoid fever in a county of Yunnan province, 2010-2011]

Objective: To identify the source and to comment on control program regarding an outbreak of paratyphoid A fever in a county, through field studies. Methods: Descriptive epidemiological methods were adopted to describe the epidemiological characteristics of the outbreak, which occurred in Yuanjiang county, Yunan province between 2010-2011, China. Case-control study with environmental investigation was performed to identify related risk factors and pathogens while isolation and susceptibility on the suspected pathogens were conducted. Subsequently, intervention and preventive measures were taken for the control of the outbreak. Results: A total of 600 cases were diagnosed and reported as paratyphoid fever A which spread over the whole Yuanjiang county, including 10 townships with different incidence rates. The disease was spatially clustered and the prevalence rates in these townships decreased with increasing distances from the polluted fields. Data from the case-control study discovered that consumption of raw vegetables was the main risk factor associated with this outbreak of paratyphoid fever (OR=65.3, P<0.001). Management of patients did not meet the requirements while feces and urine of the outpatients polluted the wastewater system in the city. Salmonella paratyphi A isolates were identified from the improperly disinfected wastewaters in hospitals and city systems, respectively. After the measures as prohibiting the planting of vegetables in contaminated fields and disinfection of hospital wastewater were taken, the outbreak subsided. Conclusions: Urban and hospital wastewater used for vegetables irrigation together with the tradition of eating uncooked vegetables seemed responsible for the outbreak of this paratyphoid fever. Intervention programs carried by the local government played a key role in controlling this large outbreak.

Trends in hip fracture rates in Taiwan: a nationwide study from 1996 to 2010

There was an initial increase and a later decrease in hip fracture rates in Taiwan between 1996 and 2010 (457.9 to 390.0 fractures per 100,000 people per year). Mortality rates decreased but re-emerged later (2.26 to 1.91 deaths per 100 hip fracture admissions). The turning point for change in trends was 2003.

INTRODUCTION

Fractures of the proximal femur remain a major cause of mortality and morbidity. We aimed to examine recent trends in hip fracture rates, in-hospital mortality rates, and length of hospital stay (LOS) due to hip fractures in people aged 55 and over in Taiwan.

METHODS

This is a time-trend study. We used data from the National Health Insurance Research Database between 1996 and 2010 in Taiwan. Insurants aged 55 and over were included. The outcome measures were age-adjusted hip fracture rates, age-adjusted in-hospital mortality rates, and LOS due to hip fractures. We classified hip fractures into femoral neck, trochanteric, and subtrochanteric fractures.

RESULTS

We identified 250,919 hospitalizations for hip fractures. The total number of hip fractures increased steadily from 12,479 to 19,841 cases. There was a trend towards initial increase and then later decrease in hip fracture rates (from 457.9 to 390.0 fractures per 100,000 people per year). LOS decreased by 46.5 % (17.53 to 9.38 days). By contrast, mortality rates for hip fractures decreased initially, but re-emerged later with a total decrement of 15.5 % (2.26 to 1.91 deaths per 100 hip fracture admissions). Women outnumbered men in all types of hip fractures, but men had higher in hospital mortality rates. LOS was similar between genders and among age groups. The turning point for change in trends was year 2003.

CONCLUSIONS

While LOS shortened gradually since 1996, the absolute number of hip fractures in Taiwan continues to rise. There is still room for improvement in reducing mortality due to hip fractures.

Association between teriparatide treatment persistence and adherence, and fracture incidence in Taiwan: analysis using the National Health Insurance Research Database

Medication persistence and adherence are critical for osteoporosis outcomes. Using the Taiwan National Health Insurance Research Database, we found that persistence and adherence to teriparatide were low in Taiwanese patients with osteoporosis and that greater persistence and adherence were associated with a lower incidence of hip and other nonvertebral fractures.

INTRODUCTION

The purpose of this study was to determine the persistence and adherence to teriparatide treatment in Taiwanese patients with osteoporosis, and to examine the association between persistence and adherence to teriparatide with fracture risks.

METHODS

Medical and pharmacy claims for 4,692 patients with vertebral or hip fractures and teriparatide prescriptions between 2005 and 2008 were identified (Taiwan National Health Insurance Research Database). Persistence was the time from the start of treatment to the first 90-day gap between two teriparatide prescriptions. Adherence was the number of teriparatide pens (each pen is used over 1 month) prescribed over 24 months. Association of persistence and adherence to teriparatide with fracture incidence was assessed using adjusted Cox proportional hazards models.

RESULTS

The proportion of patients persisting with teriparatide for >6 months and >12 months was 44.6 and 24.9 %, respectively. Over 24 months, 53.6 % of patients were adherent for >6 months and 33.9 % were adherent for >12 months. Patients persisting for >12 months had a significantly lower incidence of hip (adjusted hazard ratio [HR], 0.61 [95 % confidence interval (CI), 0.40-0.93], P = 0.0229) and nonvertebral fracture (HR, 0.79 [95 % CI, 0.63-0.99], P = 0.0462) compared with those who persisted for ≤12 months. Patients adherent for >12 months had a lower incidence of hip (HR, 0.66 [95 % CI, 0.46-0.96], P = 0.0286) and nonvertebral fracture (HR, 0.81 [95 % CI, 0.66-0.99], P = 0.0377) compared with those adherent for ≤12 months.

CONCLUSIONS

Persistence and adherence to teriparatide over 24 months were low in Taiwanese patients with osteoporosis; greater adherence and persistence were associated with a lower incidence of nonvertebral fractures.

A replicating plasmid-based vector for GFP expression in Mycoplasma hyopneumoniae

Mycoplasma hyopneumoniae (M. hyopneumoniae) causes porcine enzootic pneumonia (PEP) that significantly affects the pig industry worldwide. Despite the availability of the whole genome sequence, studies on the pathogenesis of this organism have been limited due to the lack of a genetic manipulation system. Therefore, the aim of the current study was to generate a general GFP reporter vector based on a replicating plasmid. Here, we describe the feasibility of GFP reporter expression in M. hyopneumoniae (strain 168L) controlled by the p97 gene promoter of this mycoplasma. An expression plasmid (pMD18-TOgfp) containing the p97 gene promoter, and origin of replication (oriC) of M. hyopneumoniae, tetracycline resistant marker (tetM), and GFP was constructed and used to transform competent M. hyopneumoniae cells. We observed green fluorescence in M. hyopneumoniae transformants under fluorescence microscopy, which indicates that there was expression of the GFP reporter that was driven by the p97 gene promoter. Additionally, an electroporation method for M. hyopneumoniae with an efficiency of approximately 1 x 10(-6) transformants/μg plasmid DNA was optimized and is described herein. In conclusion, our data demonstrate the susceptibility of M. hyopneumoniae to genetic manipulation whereby foreign genes are expressed. This work may encourage the development of genetic tools to manipulate the genome of M. hyopneumoniae for functional genomic analyses.

Risk of refracture associated with compliance and persistence with bisphosphonate therapy in Taiwan

SUMMARY

Bisphosphonates have been used for the treatment of postmenopausal osteoporosis since the early 1990s and studies show that compliant patients experience a lower fracture rate. This cohort study showed that the compliance of Taiwanese patients was poor and the refracture risk was related to compliance with bisphosphonate therapy.

INTRODUCTION

Bisphosphonates are potent inhibitors of osteoclast activity, and reduce bone turnover by inhibiting bone resorption. According to Taiwanese reimbursement guidelines, patients with osteoporosis-related fractures are eligible for bisphosphonate treatment. This study aimed to elucidate the relationship of refracture risk with compliance/persistence with bisphosphonate therapy in Taiwan.

METHODS

This was a retrospective, administrative, database analysis measuring the adherence status and impact of poor adherence to bisphosphonate therapy in Taiwan. Study data derived from the National Health Insurance Research Database (NHIRD) were used to assemble a cohort of all osteoporosis patients who initiated bisphosphonate treatment between January 1, 2004, and December 31, 2005. Patients were followed until death, end of registration in NHIRD, or end of study period (December 31, 2006), whichever occurred first. Compliance was calculated as medication possession ratio (MPR; sum of days of supply of osteoporosis medications divided by follow-up duration).

RESULTS

The refracture rates for osteoporosis patients were 5.15 %, 7.36 %, and 8.49 % in the first, second, and third year, respectively, and were significantly lower for patients with >80 % compliance than with <80 % compliance (p < 0.05). Nearly 50 % patients were noncompliant (MPR < 80 %) at 3 months, and only around 30 % patients were adherent at 1 year. Refracture risk increased with MPR < 80 %, age, and co-morbidities like diabetes mellitus or dementia. Patients with concomitant statin medication had significantly lower refracture risk.

CONCLUSIONS

The compliance of Taiwanese patients with osteoporosis medication is poor, and refracture risk is related to compliance with bisphosphonate therapy.

Simultaneous osteonecrosis and osteomyelitis in a patient with cancer of the breast

Breast cancer is generally managed surgically with adjuvant agents which include hormone therapy, chemotherapy, radiotherapy and bisphosphonate therapy. However, some of these adjuvant therapies may cause adverse events, including wound infection, neutropenia, bone marrow suppression and fever. The simultaneous presentation of osteonecrosis and osteomyelitis has not previously been described in patients with breast cancer undergoing hormone therapy and chemotherapy. We report a patient with breast cancer who developed bone infarcts in both legs as well as osteomyelitis in the right distal tibia after treatment which included a modified radical mastectomy, hormone therapy and chemotherapy. Simultaneous osteonecrosis and osteomyelitis should be considered in patients with breast cancer who are receiving chemotherapy and hormone therapy who present with severe bone pain, especially if there have been infective episodes during treatment.

Water solution of onion crude powder inhibits RANKL-induced osteoclastogenesis through ERK, p38 and NF-kappaB pathways

Onion powder has been reported to decrease the ovariectomy-induced bone resorption of rats. However, the molecular mechanism of onion powder on the bone cells has not been reported. Here, we report that water solution of onion crude powder decreases the osteoclastogenesis from co-cultures of bone marrow stromal cells and macrophage cells. Additionally, water solution of onion crude powder inhibits the RANKL-induced ERK, p38 and NF-kappaB activation in macrophages. In summary, our data showed that onion powder may benefit bone through an anti-resorption effect on the osteoclasts.

INTRODUCTION

A nutritional approach is important for both prevention and treatment of osteoporosis. Onion has been reported to decrease the ovariectomy-induced bone resorption. However, the functional effects of onion on the cultured osteoclasts and osteoblasts remain largely unknown. Here, we found that water solution of onion crude powder markedly inhibited the receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclastogenesis through ERK, p38 and NF-kappaB pathways. Other studies were also designed to investigate the potential signaling pathways involved in onion-induced decrease in osteoclastogenesis.

METHODS

The osteoclastogenesis was examined using the TRAP staining method. The MAPKs and NF-kappaB pathways were measured using Western blot analysis. A transfection protocol was used to examine NF-kappaB activity.

RESULTS

Water solution of onion crude powder inhibited the RANKL plus M-CSF-induced osteoclastic differentiation from either bone marrow stromal cells or from RAW264.7 macrophage cells. Treatment of RAW264.7 macrophages with RANKL could induce the activation of ERK, p38 and NF-kappaB that was inhibited by water solution of onion crude powder. On the other hand, it did not affect the cell proliferation and differentiation of human cultured osteoblasts.

CONCLUSIONS

Our data suggest that water solution of onion crude powder inhibits osteoclastogenesis from co-cultures of bone marrow stromal cells and macrophage cells via attenuation of RANKL-induced ERK, p38 and NF-kappaB activation.

Bone Mineral Density in Long-Term Chinese Heart Transplant Recipients: A Cross-Sectional Study

Osteoporosis, which usually peaks during 6 to 12 months after transplantation, remains an important concern after heart transplantation. Immunosuppressants contribute to this phenomenon. Glucocorticoids are well documented to cause bone loss, but the role of cyclosporine (CsA) remains controversial, especially among long-term recipients on low doses of steroid. We herein report a cross-sectional study of bone mineral density (BMD) among long-term Chinese heart transplant recipients. We enrolled 41 patients of mean age 50.15 +/- 13.58 years with a mean follow-up of 57.02 months. Lumbar spine and femoral neck BMD were measured by dual energy x-ray absorptiometry. Trough CsA levels (C(0)) and markers of mineral metabolism, including bone-specific alkaline phosphatase and urinary N-telopeptide, were determined by immunoassay. Sixty six percent of subjects showed bone loss at the femoral neck, significantly more than those in the lumbar spine. Those receiving a higher CsA dosage (<2.5 mg/kg/d) showed greater femoral neck BMD, but lower serum creatinine values. Our results demonstrated that bone loss remains long after transplantation, though bone markers are within normal limits.

Home-based trunk-strengthening exercise for osteoporotic and osteopenic postmenopausal women without fracture--a pilot study

OBJECTIVES

To investigate whether a 12-week home-based programme of trunk-strengthening exercise could benefit spinal mobility, function and quality of life for osteoporotic and osteopenic postmenopausal women without fracture.

DESIGNS

Randomized controlled clinical trial.

SETTING

Department of Physical Therapy in National Taiwan University Hospital.

SUBJECTS

Twenty-eight postmenopausal women (mean age 60.3+/-9.3 years) diagnosed with osteoporosis or osteopenia without fracture history were recruited for this study. Subjects were randomly assigned into exercise or control groups, each consisting of 14 subjects.

INTERVENTIONS

The 12-week exercise programme included strengthening routines for the trunk extensor and flexor muscles. The subjects performed three sets of 10 repetitions for each of the exercises, with programmes carried out three times per day at home.

MAIN OUTCOME MEASUREMENTS

Muscular strength, spinal range of motion (ROM) and motion velocity, Oswestry Disability Questionnaire (ODQ) and quality of life (QOL) were measured before the start and after completion of the exercise programme.

RESULTS

Statistically significant improvements were demonstrated in spinal ROM and motion velocity in the sagittal and frontal planes for the exercise group (p<0.05). Further, the strength of the trunk flexors and extensors increased after exercise training (p<0.05). ODQ measure was significantly reduced in the exercise group (p<0.05), while the controls showed no significant change. Subjects in the exercise group showed better satisfaction in some domains of the Short-Form-36 Health Survey quality of life questionnaire (p<0.05).

CONCLUSIONS

This 12-week home-based trunk-strengthening exercise programme could improve trunk mobility and strength, and enhance QOL in osteoporotic and osteopenic postmenopausal women without vertebral fracture. Future study should recruit more cases or more severe subjects to verify the results.

Hospital-based allogenic bone bank--10-year experience

Bone banking in a hospital provides resources of allogenic bone grafts. However, they may transmit infection from donor to recipient. We found few reports discussing the infection rate and monitoring processes associated with bone banks. The discard rate using the screening test was 18.5% (309/1674) in this series. The leading cause was hepatitis B antigen (HBsAg) positive donor serum (67%), followed by Venereal Disease Research Laboratory (VDRL) positive donor serum (15%), and anti-hepatitis C virus (HCV) positive donor serum (12%). The overall infection rate in the recipients was 1.3% (17/1365). Among 1353 implanted allografts, 22 cases (1.6%) had a positive swab culture result after thawing. Only four out of these 22 cases (18.2%) developed infection. However, the wound cultures of the infected recipients were different from the swab culture of thawing allografts except in one case. Among the 1331 recipients with sterile allograft bones, 13 (1%) were found to have infection. In conclusion, our bone bank operates under a strict monitoring system which results in a low infection rate. The recipient's status, the aseptic technique and environment during operation is likely to be more critical in prevention of allograft-related infection.

High incidence rate of hip fracture in Taiwan: estimated from a nationwide health insurance database

The objective of this study was to describe the incidence rate of hip fracture from 1996 to 2000 in Taiwan, based on an inpatient database of the National Health Insurance Program. A total of 54,199 patients, who had a first-time admission for a diagnosis of hip fracture (ICD9 code 820.0 through 820.9, 820.21, 820.22, and 820.31) on discharge from January 1996 through December 2000 and aged 50 to 100 years, were identified and included in the study. The results showed that the age-specific incidence rates of hip fractures were higher with increasing age in both genders, in an exponential manner after 65 years of age. The incidence was 1.6 times higher and rose about 5 years earlier among women than among men. Thus in these 5 years the age-adjusted incidence rates (95% confidence interval) of hip fracture in Taiwan were 225 (95% CI, 188-263) per 100,000 in men and 505 (95% CI, 423-585) per 100,000 in women (adjusted to US white population of 1989), as compared with US white rate of 187 in men and 535 in women. More than half of the fractures were peritrochanteric, and the recorded cause in most cases was a fall on the same level, from slipping, tripping, or stumbling (ICD9 E885). A total of 37.8% patients had hip hemiarthroplasty, 51.2% had open reduction of fracture with internal fixation, and 10.5% had closed reduction of fracture with internal fixation. We concluded that, using the data from a nationwide health insurance database of Taiwan, we found a high annual incidence rate of hip fracture for both men and women in 5 consecutive years. These incidence rates were higher than other reports on Chinese populations reported in the past 10 years and similar to that of Western countries. With the rapid aging of the populations of Taiwan and other Asian countries in the years to come, our results clearly demonstrated the impact of osteoporosis and hip fracture in this region.

Effects of different exercise modes on mineralization, structure, and biomechanical properties of growing bone

Weight bearing during exercise plays an important role in improving the mechanical properties of bone. The effect on bone of non-weight-bearing exercise such as swimming remains controversial. To investigate the effects of exercise mode on growing bone, 29 male Wistar rats (7 wk old) were randomly assigned to a running exercise group (Run, n = 9), a swimming exercise group (Swim, n = 10), or a nonexercise control group (Con, n = 10). During an 8-wk training session (20-60 min/day, 5 days/wk), the Run rats were trained at progressively increasing running speeds (12-22 m/min), and weights attached to the tail of the Swim rats were progressively increased from 0 to 2% of their body weight. The bone mineral density of the proximal tibiae of the Run rats was significantly higher than in the Swim (P < 0.05). Femoral wet weights of the two exercise groups were significantly higher than in the control group (P < 0.05). Interestingly, the percent difference between the tissue wet weight and dry weight (water content ratio), which is related to bone mechanical properties, was significantly higher in the tibiae of the Swim rats and the femora of both exercise groups compared with controls (P < 0.05). Extrinsic as well as intrinsic biomechanical material properties were measured in a three-point bending test. Bone mechanical properties of the tibiae and femora of rats in the Swim and Run groups were significantly greater than those in the control group (P < 0.05). In summary, different modes of exercise may benefit bone mechanical properties in different ways. The specific effects of swimming exercise (non-weight-bearing exercise) on bone require further study.

Effects of caffeine and exercise on the development of bone: a densitometric and histomorphometric study in young Wistar rats

High doses of caffeine will induce calcium loss and influence the normal development of bone, whereas the proper exercise has positive effects on bone metabolism. This study investigated the possible effects of exercise to antagonize the caffeine-induced impairment of bone development in young male Wistar rats. A total of 32 male rats (5 weeks old) were divided randomly into four groups: group 1 rats were fed caffeine; group 2 rats were prescribed an exercise program; group 3 rats were fed caffeine and prescribed an exercise program; and group 4 rats served as the control group. The caffeine was fed via the animals' dietary water and the dosage was 10 mg/100 g body weight per day, 3 days a week. The exercise program was carried out on a treadmill for 10 weeks (5 days/week, 1 h/day, 70% VO(2)max). Body weight was measured weekly. After sacrifice, the tibia length was measured and the tibia was processed for histomorphometric analysis. Bone mineral density was measured by dual-energy X-ray absorptiometer at three different sites of the tibia. In addition, the calcium content of the right femur was measured by atomic absorptiometry. The results showed that both exercise and caffeine significantly lowered the body weight gain. Rats fed with caffeine (groups 1 and 3) had a significantly longer tibia as compared with the non-caffeine-fed rats (groups 2 and 4) (p = 0.0149). The histomorphometry study showed that thickness of the growth plate in the proliferative zone, the hypertrophic zone, and total growth plate was greater in caffeine-fed groups than in non-caffeine-fed groups. The cell number in the proliferative zone was higher in the caffeine-fed groups. Area ratio of trabeculae in the primary spongiosa of rats in groups 1 and 2 were significantly greater than the control group. Caffeine feeding (groups 1 and 3) induced a lower area ratio of bone trabeculae in the secondary spongiosa, whereas exercise training (groups 2 and 3) increased the thickness of the trabeculae. The exercise program counteracted the negative effect of caffeine on the trabecular thickness, but did not correct the trabecular bone ratio. The bone mineral density (BMD) of the tibia was significantly lower in caffeine-fed rats, and the exercise program did not show any counteracting effect on the caffeine-induced BMD reduction. The calcium content assay showed that caffeine feeding decreased the weight and total calcium content of the femur. Again this exercise program did not counterbalance the negative effects of caffeine. In conclusion, high doses of caffeine seemed to stimulate the growth of long bone. However, it caused more serious negative effects on bone, including bone mineral loss, lower BMD, and lower calcium content. Exercise training at 70% VO(2)max had little antagonizing effect on caffeine-induced impairment of bone formation. Therefore, the best way to prevent caffeine-induced negative effects on bone development is to lower caffeine exposure.

Spinal performance and functional impairment in postmenopausal women with osteoporosis and osteopenia without vertebral fracture

Previous studies have paid much attention to the impact on functional impairment or quality of life from vertebral fractures secondary to osteoporosis, but little research has addressed the function of osteoporotic women without fractures. The purposes of this study were: (1) to describe spinal performance and functional impairment in postmenopausal women with osteoporosis and osteopenia without vertebral fracture, and (2) to investigate the relationship between them. Thirty postmenopausal women diagnosed as having osteoporosis or osteopenia were recruited who fulfilled the following criteria: (1) menopause for at least 6 months; (2) no vertebral fracture; (3) no medication that would interfere with calcium intake. Measurements included assessment of functional impairment and spinal performance including trunk extension/flexion isokinetic strength, spinal range of motion (ROM) and movement velocity in three planes (sagittal, frontal and transverse). The results showed that spinal ROM and velocity were significantly reduced in the osteoporosis group compared with the osteopenia group ( p<0.05), but no significant difference in trunk strength was shown. Functional impairment level showed a slight difference between the two groups ( p = 0.042). There was a significant correlation between spinal ROM and motion velocity with bone mineral density; however, functional impairment correlated with motion velocity only in the transverse plane (trunk rotation) ( p<0.05). Spinal strength did not show any correlation with other parameters. It was concluded that spinal motion performance declined and functional impairment increased in relation to the severity of bone mineral loss in postmenopausal women without vertebral fracture, but their physical performance was not correlated with functional impairments.

A biologically based model of growth and senescence of Syrian hamster embryo (SHE) cells after exposure to arsenic

We modified the two-stage Moolgavkar-Venzon-Knudson (MVK) model for use with Syrian hamster embryo (SHE) cell neoplastic progression. Five phenotypic stages are proposed in this model: Normal cells can either become senescent or mutate into immortal cells followed by anchorage-independent growth and tumorigenic stages. The growth of normal SHE cells was controlled by their division, death, and senescence rates, and all senescent cells were converted from normal cells. In this report, we tested the modeling of cell kinetics of the first two phenotypic stages against experimental data evaluating the effects of arsenic on SHE cells. We assessed cell division and death rates using flow cytometry and correlated cell division rates to the degree of confluence of cell cultures. The mean cell death rate was approximately equal to 1% of the average division rate. Arsenic did not induce immortalization or further mutations of SHE cells at concentrations of 2 microM and below, and chromium (3.6 microM) and lead (100 microM) had similar negative results. However, the growth of SHE cells was inhibited by 5.4 microM arsenic after a 2-day exposure, with cells becoming senescent after only 16 population doublings. In contrast, normal cells and cells exposed to lower arsenic concentrations grew normally for at least 30 population doublings. The biologically based model successfully predicted the growth of normal and arsenic-treated cells, as well as the senescence rates. Mechanisms responsible for inducing cellular senescence in SHE cells exposed to arsenic may help explain the apparent inability of arsenic to induce neoplasia in experimental animals.

Toxicological interactions among arsenic, cadmium, chromium, and lead in human keratinocytes

To evaluate health effects of chemical mixtures, such as multiple heavy metals in drinking water, we have been developing efficient and accurate hazard identification strategies. Thus, in this study, we determine the cytotoxicity of arsenic, cadmium, chromium, and lead, and characterize interactions among these metals in human epidermal keratinocytes. Three immortal keratinocyte cell lines (RHEK-1, HaCaT, and NM1) and primary keratinocytes (NHEK) were used. A statistical approach applying an additivity response surface methodology was used to test the validity of the additivity concept for a 4-metal mixture. Responses of the 4 keratinocyte strains to the metal mixture were highly dose-dependent. A growth stimulatory effect (hormesis) was observed in RHEK-1, NM1, and NHEK cells with the metal mixture at low concentrations (low ppb range). This hormesis effect was not significant in HaCaT. As the mixture concentration increased, a trend of additivity changed to synergistic cytotoxicity in all 4 cell strains. However, in NHEK, RHEK-1, and HaCaT, at the highest mixture concentrations tested, the responses to the metal mixtures were antagonistic. In NM1, no significant antagonistic interaction among the metals was observed. To explore a mechanistic basis for these differential sensitivities, levels of glutathione and metallothioneins I and II were determined in the keratinocyte cell strains. Initial data are consistent with the suggestion that synergistic cytotoxicity turned to antagonistic effects because at highest mixture exposure concentrations cellular defense mechanisms were enhanced.

Contact stress on polyethylene components of a new rotating hinge with a spherical contact surface

OBJECTIVE

To assess the nonlinear contact stress of a new rotating hinge of our knee prosthesis at various rotation angles.

DESIGN

The contact surface between the metal tibial bearing and the ultra-high-molecular weight polyethylene plate of a conventional rotating hinge is of cylindrical design. We have designed a new type of rotating hinge with a congruous spherical contact surface.

BACKGROUND

The endoprosthesis for reconstruction of limb after wide resection of malignant tumor around knee usually incorporates a rotating hinge. Our new rotating hinge with a spherical contact surface incorporates the benefits of an increased contact surface and potentially increased rotational stability during axial loading.

METHODS

We utilized the ABAQUS finite element program to assess the nonlinear contact stress of this new rotating hinge at rotation angles of 0 degrees, 4 degrees and 8 degrees, based on a contact force of about 2800 N.

RESULTS

The results show that von Mises stress for the finite element model of the polyethylene component of this rotating hinge ranges from 4.90 x 10(-6) to 8.22 MPa at the aforementioned rotational angles. The von Mises stress is about 1.31--1.82 MPa on the major parts of the ultra-high-molecular weight polyethylene plate, including both flanks. There is a mild stress concentration on the outer edge of polyethylene component, especially at 4 degrees and 8 degrees of rotation. The maximum values of von Mises stress at the contact surface at 0 degrees, 4 degrees and 8 degrees of rotation are 5.92, 7.49 and 8.22 MPa, respectively. These contact stresses are within the safety range of the ultra-high-molecular weight polyethylene (compressive yield strength, 14 MPa).

CONCLUSIONS

This new rotating hinge has an evenly distributed contact stress during axial load because of congruous contact design.

Rhodostomin, a snake venom disintegrin, inhibits angiogenesis elicited by basic fibroblast growth factor and suppresses tumor growth by a selective alpha(v)beta(3) blockade of endothelial cells

Angiogenesis consists of the proliferation, migration, and differentiation of endothelial cells, although angiogenic factor and integrin-extracellular matrix interaction modulate this process. We report here that a snake venom-derived disintegrin, rhodostomin, inhibited distinct steps in angiogenesis elicited by basic fibroblast growth factor (bFGF), and also suppressed in vivo murine melanoma tumor growth. Rhodostomin dose-dependently inhibited bFGF-induced human umbilical vein endothelial cell (HUVEC) proliferation as examined by cell number count, metabolic activity, and BrdU incorporation assays with submicromolar IC(50) values. However, it apparently did not affect the viability of murine B16F10 melanoma cells, even up to 50 microM. Rhodostomin also inhibited HUVEC migration and invasion evoked by bFGF, and tube formation of bFGF-treated HUVECs in Matrigel. Moreover, rhodostomin selectively inhibited bFGF-, but not vascular endothelial growth factor-associated angiogenesis in the chick chorioallantoic membrane model. Furthermore, rhodostomin blocked both bFGF- and B16F10-induced neovascularization in murine Matrigel plug model and suppressed the growth of subcutaneously inoculated B16F10 solid tumor, leading to a prolonged survival of the rhodostomin-treated C57BL/6 mice. The antiangiogenic effect of rhodostomin on bFGF-treated HUVECs is related to the integrin alpha(v)beta(3) blockade, as evidenced by its selective inhibition on the binding of 7E3, a monoclonal antibody (mAb) raised against alpha(v)beta(3,) but not that of P1F6, an alpha(v)beta(5) mAb toward both naive and bFGF-primed HUVECs. Moreover, 7E3 specifically blocked fluorescein isothiocyanate-conjugated rhodostomin binding to HUVEC, whereas P1F6 and anti-integrin alpha(2), alpha(3), alpha(4), or alpha(5) mAbs did not.

Assessing interaction thresholds for trichloroethylene in combination with tetrachloroethylene and 1,1,1-trichloroethane using gas uptake studies and PBPK modeling

The volatile organic solvents trichloroethylene (TCE), tetrachloroethylene (perchloroethylene, PERC), and 1,1,1-trichloroethane (methylchloroform, MC) are widely distributed environmental pollutants and common contaminants of many chemical waste sites. To investigate the mode of pharmacokinetic interactions among TCE, PERC, and MC and to calculate defined "interaction thresholds", gas-uptake experiments were performed using a closed-chamber exposure system. In each experiment, two rats (Fischer 344, male, 8-9 weeks old) were exposed to different initial concentrations of TCE, PERC, and MC, applied singly or as a mixture, and their concentration in the gas phase of the chamber was monitored over a period of 6 h. A physiologically based pharmacokinetic (PBPK) model was developed to test multiple mechanisms of inhibitory interactions, i.e., competitive, non-competitive, or uncompetitive. All mixture exposure data were accurately described by a system of equations in which a PBPK model was provided for each chemical and each was regarded as an inhibitor of the others' metabolism. Sensitivity-analysis techniques were used to investigate the impact of key parameters on model output and optimize experimental design. Model simulations indicated that, among these three chemicals, the inhibition was competitive. The PBPK model was extended to assess occupationally relevant exposures at or below the current threshold-limit values (TLVs). Based on 10% elevation in TCE blood levels as a criterion for significant interaction and assuming TCE exposure is set at TLV of 50 ppm, the calculated interaction thresholds for PERC and MC were 25 and 135 ppm, respectively. TLV exposures to binary TCE/PERC mixture were below the 10% significance level. The interaction threshold for TCE and MC co-exposure would be reached at 50 and 175 ppm, respectively. Such interactive PBPK models should be of value in risk assessment of occupational and environmental exposure to solvent mixtures.

Effects of gender and age differences on the distribution of bone content in the third lumbar vertebra

STUDY DESIGN

A cross-sectional study on the distribution of bone mineral content in the third lumbar vertebrae.

OBJECTIVES

To evaluate the effects of age and gender on the distribution of bone mineral content in the third lumbar vertebrae.

SUMMARY OF BACKGROUND DATA

Compression fractures occur mainly at the vertebral body. Variations in the distribution of bone mass in a vertebra, if undefined, may bias the ability of the acquired bone mineral density values, which was usually measured posteroanteriorly, to predict the risk of fractures.

METHODS

The bone mineral content of the whole L3, including the L3 vertebral body and the posterior segment, was measured using a lateral approach with a dual energy radiograph absorptiometer on 177 healthy Taiwanese adults including 65 men and 55 premenopausal and 57 postmenopausal women.

RESULTS

The proportion of bone mineral content in the vertebral body was significantly lower in premenopausal women than in age-matched men (39.1 +/- 0.9% vs. 50.0 +/- 1.7%, P < 0.0001). Furthermore, whereas postmenopausal women showed a decreased proportion of bone mineral content in the vertebral body with increased age (about -0.0022 per year, P = 0.0001), premenopausal women and men showed a sustained proportion.

CONCLUSIONS

The proportion of bone mineral content distributed in the body of L3 vertebrae was lower in women than in men. The discrepancy of this parameter between the genders was even larger with increased ages.

A clonal growth model: time-course simulations of liver foci growth following penta- or hexachlorobenzene treatment in a medium-term bioassay

A combination of experimental and simulation approaches were used to analyze the clonal growth of preneoplastic, enzyme-altered foci during liver carcinogenesis in an initiation-promotion regimen. Male Fisher 344 rats, 8 weeks of age, were initiated with a single dose (200 mg/kg, i.p.) of diethylnitrosamine (DEN). Beginning 2 weeks later, animals were exposed to daily gavage consisting of 0.1 mmol/kg pentachlorobenzene (PECB) or hexachlorobenzene (HCB) in corn oil vehicle for 6 weeks. Partial hepatectomy was performed 3 weeks after initiation. Experimental data including liver weight, hepatocyte density (number of hepatocytes/unit volume), 5-bromo-2'-deoxyuridine-labeling index for analysis of cell division rate, and number and volume of glutathione-S-transferase pi-positive foci were collected 23, 26, 28, 47, or 56 days after initiation. Model parameters describing liver growth were obtained directly from the experimental data. The probability of mutation/division of normal cells and the growth rate of initiated cells were inferred by a comparison of model outcomes with the observed time courses of foci development. To describe the time-dependent increases in foci volume and the concomitant reduction of foci number observed in all treatment groups, the calibrated model for the DEN controls incorporated the hypothesis of two initiated cell populations (referred to as A and B cells) within the framework of the two-stage model. The B cells are initiated cells that have a selective growth advantage under conditions that inhibit the growth of A cells and normal hepatocytes. The parameter values defined in the DEN controls were used to evaluate experiments involving the administration of PECB or HCB. Both PECB and HCB caused a significant increase in foci volume compared with the DEN controls. HCB treatments resulted in increased proliferation of normal hepatocytes, which was not observed for PECB under the same treatment regimen. The best description of the data resulted from the model incorporating the hypothesis that PECB and HCB promoted the growth of foci via increased net growth rates of B cells. We present here a biologically based clonal growth simulation platform to describe the growth of preneoplastic foci under experimental manipulations of initiation-promotion studies. This simulation work is an example of quantitative approaches that could be useful for the analysis of other initiation-promotion studies.

Effectiveness of a multidisciplinary rehabilitation program in elderly patients with hip fractures

BACKGROUND AND PURPOSE

Hip fracture is a significant health challenge to the elderly, with a high risk of complications, long hospital stay, and functional deterioration. The purpose of this study was to evaluate the effectiveness of a multidisciplinary rehabilitation program (MRP) in older patients with hip fractures.

METHODS

A before-and-after quasi-experimental design was used. Data were collected at a large teaching hospital in Taipei. The first 105 consecutive patients admitted received conventional care (control group). The next 50 consecutive patients received physical therapy, nurse-supervised exercise, and discharge planning (intervention group). Subjects were assessed upon admission, on the fourth postoperative day, and on the discharge day. The 155 patients recruited met the following criteria: 60 years of age or older, and hospitalized to receive either closed reduction and internal fixation, or hip arthroplasty.

RESULTS

Compared with the control group, the intervention group had a shorter average hospital stay (9.9 vs 11.6 days, p = 0.01), earlier ambulation (5.7 vs 6.5 days postoperatively), and a lower rate of bowel incontinence (4.0% vs 23.8%) and pressure sores (14.0% vs 24.8%) during hospitalization. The intervention group experienced less decline in mobility (relative to pre-fracture status) than the control group. No significant difference was found in other outcome variables between the control and intervention groups.

CONCLUSIONS

The findings of this study indicate that an MRP involving physical therapy, nurse-supervised exercise, and discharge planning positively affects health outcomes in older patients with hip fractures.

Pharmacokinetics, metabolism, and carcinogenicity of arsenic

The carcinogenicity of arsenic in humans has been unambiguously demonstrated in a variety of epidemiological studies encompassing geographically diverse study populations and multiple exposure scenarios. Despite the abundance of human data, our knowledge of the mechanism(s) responsible for the carcinogenic effects of arsenic remains incomplete. A deeper understanding of these mechanisms is highly dependent on the development of appropriate experimental models, both in vitro and in vivo, for future mechanistic investigations. Suitable in vitro models would facilitate further investigation of the critical chemical species (arsenate/arsenite/MMA/DMA) involved in the carcinogenic process, as well as the evaluation of the generation and role of ROS. Mechanisms underlying the clastogenic effects of arsenic, its role in modulating DNA methylation, and the phenomenon of inducible tolerance could all be more completely investigated using in vitro models. The mechanisms involved in arsenic's inhibition of ubiquitin-mediated proteolysis demand further attention, particularly with respect to its effects on cell proliferation and DNA repair. Exploration of the mechanisms responsible for the protective or anticarcinogenic effects of arsenic could also enhance our understanding of the cellular and molecular interactions that influence its carcinogenicity. In addition, appropriate in vivo models must be developed that consider the action of arsenic as a promoter and/or progressor. In vivo models that allow further investigation of the comutagenic effects of arsenic are also especially necessary. Such models may employ initiation-promotion-progression bioassays or transgenic animals. Both in vitro and in vivo models have the potential to greatly enhance our current understanding of the cellular and molecular interactions of arsenic and its metabolites in target tissues. However, refinement of our knowledge of the mechanistic aspects of arsenic carcinogenicity is not alone sufficient; an understanding of the pharmacokinetics and target tissue doses of the critical chemical species is essential. Additionally, a more thorough characterization of species differences in the tissue kinetics of arsenic and its methylated metabolites would facilitate the development of more accurate and relevant PBPK models. Improved models could be used to further investigate the existence of a methylation threshold for arsenic and its relevance to arsenic carcinogenicity in humans. The significance of alterations in relative tissue concentrations of SAM and SAH deserves further attention, particularly with respect to their role in modulating methyltransferases involved in arsenic metabolism and DNA methylation. The importance of genetic polymorphisms and nutrition in influencing methyltransferase activities must not be overlooked. In vivo models are necessary to evaluate these factors; transgenic or knockout models would be particularly useful in the investigation of methylation polymorphisms. Further evaluation of methylation polymorphisms in human populations is also warranted. Other in vivo models incorporating dietary manipulation could provide valuable insight into the role of nutrition in the carcinogenicity of arsenic. With more complete knowledge of the pharmacokinetics of arsenic metabolism and the mechanisms associated with its carcinogenic effects, development of more reliable risk assessment strategies are possible. Integration of data, both pharmacokinetic and mechanistic in nature, will lead to more accurate descriptions of the interactions that occur between the active chemical species and cellular constituents which lead to the development of cancer. This knowledge, in turn, will facilitate the development of more accurate and reliable risk assessment strategies for arsenic.

Efficacy of a 24-week aerobic exercise program for osteopenic postmenopausal women

Osteoporosis is one of the most common skeletal disorders affecting postmenopausal women. The purpose of this study was to investigate whether a 24-week program of aerobic high-impact loading exercise was beneficial for enhancing physical fitness and bone mineral density (BMD) in osteopenic postmenopausal women. Forty-three postmenopausal women aged 48-65 years participated in this study. The BMD of the spine (L2-L4) and right femoral neck of each woman was below 1 SD of the mean of premenopausal women, as examined by dual X-ray absorptiometry. The assignment of subjects into exercise or control group was not randomized but based on each subject's anticipated compliance to the 6-month long exercise program. Twenty-two subjects joined the exercise group and attended the training programs and 21 served as the control group. Exercise programs included treadmill walking at an intensity above 70% of maximal oxygen consumption (VO2max) for 30 minutes, followed by 10 minutes of stepping exercise using a 20-cm-high bench. The program was conducted three times per week for 24 weeks. Physical fitness measurements included testing of flexibility, muscular strength and endurance, body composition, and cardiopulmonary fitness. The results showed that the quadriceps strength, muscular endurance, and VO2max in the exercise group had significant improvements, whereas no improvement was found in any of the physical fitness parameters in the control group. The BMD of the L2-L4 and the femoral neck in the exercise group increased 2.0% (P > 0.05) and 6.8% (P < 0.05) and those in the control group decreased 2.3% (P < 0.05) and 1.5% (P > 0.05), respectively. In conclusion, aerobics combined with high-impact exercise at a moderate intensity was effective in offsetting the decline in BMD in osteopenic postmenopausal women.

Intracortical osteosarcoma: report of a case

Intracortical osteosarcoma is the rarest anatomic variation of osteosarcoma. There have been only 12 cases reported in the English-language literature. We present a case of osteosarcoma in an 18-year-old Taiwanese man that originated within the cortex of the tibial diaphysis. The initial radiograph revealed a lytic mass confined to the cortex, mimicking a benign bone lesion. Histopathologic examination of the biopsy specimen showed an osteoblastic osteosarcoma mingled with some fibroblastic foci. He underwent en bloc resection, and a metallic prosthetic intercalary stem was used to replace the larger bone defect. Adjuvant chemotherapy was administered before and after the operation. He was free of disease during 40 months of follow-up. A review of all reported cases of intracortical osteosarcoma revealed that the initial method of treatment plays an important role in local recurrence and distant metastasis. Local excision and curettage leads to the worst results. The outcomes of more recently reported cases have improved because of early awareness of the possibility of malignancy and advances in chemotherapy. However, whether patients with intracortical osteosarcoma have a different prognosis from those with conventional osteosarcoma cannot be determined, because of the small number of intracortical osteosarcoma cases available for analysis.

Subungual squamous cell carcinoma: report of 2 cases

Subungual squamous cell carcinoma (SCC) is a rare malignant tumor with an indolent course. Its etiology is unknown. It often involves the distal phalanx of the thumb or the index finger, and often presents as a chronic ulcer that is commonly misdiagnosed as chronic paronychia, pyogenic granuloma or verruca vulgaris. Approximately 150 cases of subungual SCC, including one in a Taiwanese patient, have been reported. Here, we report two cases of subungual SCC presenting as a chronic ulcer of the nail bed refractory to antibiotic treatment. One case involved the right thumb, while the other involved the right index finger. Radiographs of both cases showed an osteolytic bone lesion involving the distal phalanx. Excision biopsy revealed SCC in both cases. Both patients received amputation of the involved distal phalanx and showed no signs of reoccurrence during 5 years of follow-up. These findings suggest that all recalcitrant ulcers of the nail bed should be biopsied to facilitate early diagnosis and treatment of subungual SCC.

A physiologically based pharmacodynamic analysis of hepatic foci within a medium-term liver bioassay using pentachlorobenzene as a promoter and diethylnitrosamine as an initiator

A stochastic clonal growth model for describing quantitative changes in size and number of putative preneoplastic lesions was modified to analyze the time-course information of cell proliferation and glutathione S-transferase pi (GST-P) foci within a medium-term bioassay. The study used F344 rats and a single initiating event using diethylnitrosamine (200 mg/kg ip) at Week 0. After a 2-week recovery period, chemical treatment began by gavage administration of pentachlorobenzene (PeCB; 100 micromol/kg/day, 7 days/week) in a corn oil vehicle and continued for 6 weeks. One week after beginning gavage dosing, a two-thirds partial hepatectomy was performed and the animals were serially euthanized at 48, 120, 168, 624, and 840 h postsurgery, which corresponds to 216, 288, 336, 792, and 1008 h following the beginning of PeCB treatment, respectively. For analysis, two types of models were evaluated for describing the time-course changes in GST-P foci. First, a sequential model describing the transformation of normal cells into a homogenous initiated cell population (i.e., one-cell model). Second, a two-cell model that describes a heterogeneous foci population by splitting the initiated cell population into two distinct types. In our study, the one-cell model was unable to adequately represent the time-course data for changes in both size and number of foci. In contrast, the two-cell model, which was parameterized to describe a negative selection mechanism, produced adequate simulations of both the size and number of foci. This model-based analysis suggested that the differences between PeCB-treated and untreated animals were primarily in parameters involving the rates of cell death.

Rhodostomin inhibits the transforming growth factor-beta1-enhanced adhesion activity of ROS 17/2.8 osteosarcoma cells

We have investigated the effect of transforming growth factor-beta1 (TGF-beta1) on the in vitro adhesion activity of the rat osteosarcoma cell lines (ROS 17/2.8) to extracellular matrix substrata, including fibronectin, type I and IV collagen, as well as laminin. The interaction of Arg-Gly-Asp (RGD) and rhodostomin, an RGD containing snake venom, with TGF-beta1 on the cell adhesion was also evaluated. The results showed that incubation with various concentration of TGF-beta1 (1-15 ng/ml) significantly increased the adhesion activity (1.4 to 2.5 folds) of ROS 17/2.8 to fibronectin and type I collagen (p<0.01), whereas the adhesion activity to laminin and type IV collagen was slightly elevated (1.1 to 1.5 folds). The peak effect of TGF-beta1 on the cell adhesion occurred after pretreatment of ROS 17/2.8 with TGF-beta1 for 6 hours. Treatment with Arg-Gly-Asp-Ser (RGDS) and rhodostomin effectively suppressed the TGF-beta1-enhanced adhesion activity to fibronectin and type I collagen. This study demonstrated that the up-regulated cell adhesion activity of ROS 17/2.8 cells by the TGF-beta1 can be inhibited by the rhodostomin.

Theoretical study of convergent ultrasound hyperthermia for treating bone tumors

This study investigates the optimal external parameters for using an ultrasound applicator for treating bone tumors. This system utilized spherically arranged applicators such as scanned focused ultrasound, and spherically focused multielement applicators. The power deposition pattern is modeled as geometric gain with exponential attenuation. The specific absorption rate ratio (SARR) criteria have been used to determine the proper heating domain of ultrasound driving frequency and therapeutic tumor diameter. The results demonstrate that the optimal driving frequency depends on tumor depth, ultrasound absorption of bone marrow, and diameter of bone, but it is independent of the acoustic window area and SARR. The treatable diameter of bone tumor increased when the absorption ratio of bone marrow to tumor, acoustic window of surface skin, and diameter of bone were elevated. However, the treatable diameter of bone tumor decreased when muscle thickness, SARR of bone tumor site to the surface skin, bone marrow, and bone declined. To deliver the ultrasound energy into the tumor site and to avoid the potential damage to the normal tissue as much as possible, the specific absorption rate (SAR) in the bone tumor site has to be three times higher than that in the surface skin, tumor/marrow, and marrow/bone interfaces. The temperature distributions can verify the SARR criteria in this model. This study provides the information for choosing the optimal operating frequency of the ultrasound transducer and the acoustic window on the skin surface, and for designing the ultrasound applicator for clinical implementation.

Expandable endoprosthesis reconstruction in skeletally immature patients with tumors

Between September 1984 and January 1996, 32 expandable endoprostheses were used for limb reconstruction after resection of malignant bone tumors in patients who were skeletally immature. The 20 boys and 12 girls ranged in age from 3 to 15 years (mean, 9.7 years). One patient had a Stage IIA tumor, 22 patients had Stage IIB tumors, and seven patients had Stage III tumors according to the classification of the Musculoskeletal Tumor Society. There also were two patients with parosteal osteosarcomas. The histologic diagnosis was osteosarcoma in 23 patients and Ewing's sarcoma in nine. All patients except the patients with parosteal osteosarcoma received standard neoadjuvant therapy. Twenty-two Lewis Expandable Adjustable Prostheses, four modular Wright Medical prostheses, four modular Howmedica prostheses, and two Techmedica expandable prostheses were used. Thirteen patients died, two have no evidence of disease, and 17 are continuously disease free. Sixteen of 32 patients (50%) have not had an expansion procedure because of early death in 10 and early amputation in three. Three patients are waiting to undergo an expansion procedure. Sixteen of the 32 patients (50%) have undergone 32 expansion procedures, to a maximum of 9 cm, without any infection. To maintain range of motion before the expansion procedure, a complete resection of the pseudocapsule was done routinely. Fourteen of the 32 patients did not have complications. Eighteen of the 32 patients had 27 complications. All Lewis Expandable Adjustable Prosthesis endoprostheses and the two nonmodular Techmedica prostheses were associated with a large amount of titanium debris. The children's functional results were similar to the results reported for adults with an average Musculoskeletal Tumor Society rating of good to excellent at the knee, fair to good at the hip, and fair about the shoulder. Rehabilitation of the knee in very young patients (5-8 years) remains problematic and careful selection of patient and family is necessary. The Lewis Expandable Adjustable Prosthesis probably should be reserved for very young patients (5-8 years) and modular systems should be used for large preadolescent and adolescent children.

The role of 67Ga in the early detection of spinal epidural abscesses

In this study, we evaluated the role of 67Ga whole-body and single photon emission tomographic (SPET) imaging in the early diagnosis and lesion localization of spinal epidural abscess before confirmation by gadolinium-enhanced magnetic resonance imaging (MRI). Six patients with fever of unknown origin had a 67Ga whole-body scan, four of whom also underwent SPET imaging. For further confirmation of a spinal epidural abscess, gadolinium-enhanced MRI was performed in all patients. All patients had increased 67Ga uptake in a spinal or paraspinal area on the whole-body scan. They were later confirmed to have a spinal epidural abscess after gadolinium-enhanced MRI. Of these six patients, five underwent surgical drainage plus parenterally administered antibiotics, and had complete or partial recovery. One died before operation due to sepsis. In conclusion, we suggest performing a 67Ga whole-body survey as early as possible in patients with fever of unknown origin, fever and back pain and/or the spinal syndrome, before MRI is performed. If a spinal epidural abscess is strongly suspected, SPET is needed for further confirmation of spinal versus non-spinal and contiguous versus non-contiguous lesion(s). If MRI is unavailable, then 67Ga scintigraphy is a satisfactory method for investigating spinal epidural abscesses.

Comparative hepatocarcinogenicity of hexachlorobenzene, pentachlorobenzene, 1,2,4,5-tetrachlorobenzene, and 1,4-dichlorobenzene: application of a medium-term liver focus bioassay and molecular and cellular indices

Of the twelve different chlorobenzene isomers, a thorough evaluation of carcinogenicity has only been assessed on monochlorobenzene, 1,2-, and 1,4-dichlorobenzene, and hexachlorobenzene. In the studies presented here, we measured the ability of 1,4-dichlorobenzene (DCB), 1,2,4,5-tetrachlorobenzene (TeCB), pentachlorobenzene (PeCB), and hexachlorobenzene (HCB) to promote glutathione S-transferase pi (GSTP1-1) positive preneoplastic foci formation in rat liver, following diethylnitrosamine (DEN) initiation. The results from these studies show that TeCB, PeCB, and HCB all promote the formation of GSTP1-1 positive foci and that DCB does not. The numbers and area of foci were greatest following HCB promotion, and TeCB and PeCB were approximately equal in their promoting ability. Levels of hepatic CYP1A2, CYP2B1/2, non-focal GSTP1-1, and c-fos were measured in response to treatment with the 4 chlorobenzene isomers, as were reduced glutathione (GSH) and oxidized glutathione (GSSG) levels. Results from these studies show that induction of CYP1A2 and CYP2B1/2 have correlation with both the presence and degree of GSTP1-1 foci promotion by the 4 chlorobenzenes. Alterations in GSH and GSSG levels were similar in PeCB- and TeCB-treated animals in that GSSG levels were significantly decreased, whereas HCB and DCB did not have this effect, although HCB treatment led to a significant increase in GSH levels. We conclude that induction of CYP1A2 or CYP2B1/2 by chlorobenzene isomers may indicate promotional ability, and that this property might be exploited to predict the hepatocarcinogenicity of other chlorobenzene isomers.

Physical activity, physical fitness, and osteopenia in postmenopausal Taiwanese women

BACKGROUND AND PURPOSE

The purpose of this cross-sectional study was to investigate whether physical activity level and physical fitness parameters differ between postmenopausal Taiwanese women with normal and subnormal bone mineral density (BMD).

METHODS

Seventy-six postmenopausal women aged from 42 to 65 years participated in this study. Women taking medication that might influence BMD measurements were not included. The BMDs of the lumbar spine (L2-4) and right femoral neck were measured using dual energy x-ray absorptiometry. Thirty-one women with both BMD values within the normal ranges (1.055 +/- 0.092 g/cm2 for the spine and 0.845 +/- 0.088 g/cm2 for the right femoral neck) of premenopausal Chinese women served as the normal density group. Another 43 women with both BMD values more than one standard deviation below the normal value (0.760 +/- 0.089 g/cm2 for the spine and 0.656 +/- 0.052 g/cm2 for the femoral neck) were recruited as the osteopenic group. Physical activity level was assessed with a 7-day recall questionnaire. Physical fitness assessment included tests of flexibility, muscular strength, endurance, body composition, and cardiopulmonary fitness. A multiple linear regression model adjusted for age, body weight, height, and years since menopause was used.

RESULTS

The results revealed that energy expenditure and maximal oxygen consumption were significantly lower in the osteopenic group than in the non-osteopenic group (p < 0.05), while flexibility, body composition, muscle strength and muscular endurance did not differ significantly between the two groups (p > 0.05).

CONCLUSIONS

These findings indicate that physical activity may play a major role in BMD levels in postmenopausal women in Taiwan. Future studies should emphasize the effect of physical exercise training on BMD in postmenopausal women.

Factor of risk for hip fracture in normal Chinese men and women in Taiwan

We have investigated the age-related change in factor of risk (Phi) for the proximal femoral load during free fall in 548 females and 240 males aged 21-79 years. These individuals were divided into either young (age <50 years) or old group (age >/=50 years). Another 26 females with hip fractures were included for comparison. The bone mineral density (BMD) of proximal femoral neck was measured by a Norland XR-26 dual-energy X-ray absorptiometer (DXA). The estimated fracture load (L) of femoral neck was calculated from the BMD with the regression equation derived by Courtney et al. [2,3] and estimated fall force (F) by body weight and height according to the regression equation derived by Nakamura et al. [6] respectively. Phi was defined as the quotient of F/L. The results showed an age-related decrease of BMD (P < 0.001) in both genders corrected for weight and height. By multiple linear regression analysis, the F decreased significantly with aging corrected for BMD in old males (partial r = -0.255, P < 0.01) and increased with aging in all females (young, partial r=0.287, p < 0.001; old, partial r = 0.252, P < 0.001). L decreased significantly with aging corrected for height and weight in males (young, partial r = -0.401, P < 0.01; old, partial r = -0.178, P < 0.05) and females (young, partial r = -0. 168, P < 0.05; old, partial r = -0.459, P < 0.001). However Phi decreased with aging in young males (P < 0.01) and females (young: P < 0.001, old: P < 0.001). Phi increased in old women but not in old men, and was higher in old women compared with old men. The 26 patients with hip fractures had a significantly higher Phi value than 85 age-matched women. In conclusion, Phi may provide a comprehensive comparison of the risk of hip fracture in the elderly population.

Lack of promotional effects of groundwater contaminant mixtures on the induction of preneoplastic foci in rat liver

F344 rats were exposed to drinking water mixtures of seven of the most common groundwater contaminants associated with hazardous waste sites [arsenic, benzene, chloroform, chromium, lead, phenol, and trichloroethylene (TCE)] as the full mixture or submixtures of the organic and/or inorganic chemicals. The lowest concentrations (1x) of the individual chemicals were environmentally realistic and below what would be expected to induce significant short-term toxicity. This study was intended to determine if previously reported increases in localized hepatocellular proliferation in response to these chemicals might be correlated with increased risk for hepatocarcinogenesis. Rats were exposed via a drinking water solution to the full seven- chemical mixture (at 1x and 10x concentrations), submixtures of the organic or inorganic chemicals (at 10x concentrations), a mixture of TCE, lead, and chloroform (TLC submixture at 10x and 100x concentrations), or deionized water as a control. The rats were evaluated for promotion of placental glutathione-S-transferase (GST-P) positive preneoplastic liver cell foci after diethylnitrosamine (DEN) initiation and partial hepatectomy. Focus formation, cell proliferation, and apoptosis were evaluated after exposure to DEN or saline controls, the chemical mixtures or deionized water controls, or combinations of these treatments. The total number and area of GST-P positive foci in DEN-treated rats exposed to the full seven-chemical mixture was increased as compared with the DEN-water controls, but this was statistically significant only for total focus area in the 1x dose group. In DEN-treated rats, the inorganic or TLC submixtures resulted in a significant reduction in number and area of GST-P positive foci. Focus area also was decreased in the organic submixture-treated group, but not significantly. Hepatocellular proliferation was not significantly changed in the chemical mixture saline groups as compared with the mixture water controls. After DEN treatment, however, cell proliferation was significantly decreased after the 10x seven-chemical and organic mixture treatments and the 100x TLC mixture treatment. Different groups showed either increased or decreased apoptotic rates which did not correlate well with proliferation rates or focus formation. Mixtures of these seven chemicals, therefore, did not appear to act as promoters of hepatic foci at environmentally relevant concentrations, and some mixture combinations appeared to decrease promotional activity.

Chronic toxicity and carcinogenicity studies of ethylenediamine dihydrochloride by dietary incorporation in Fischer 344 rats

Ethylenediamine dihydrochloride (EDA.2HCl) was incorporated into the diet and fed to Fischer 344 rats for 2 years at target doses of 0, 0.02, 0.10 or 0.35 g/kg/day (equivalent to 0.009, 0.045 and 0.158 g free EDA/kg/day). Two separate untreated control groups were used. Interim sacrifices were at 6, 12 and 18 months and the terminal sacrifice was at 24 months. Under the conditions of this study, EDA.2HCl was not carcinogenic in the Fischer 344 rat. Most toxic responses were observed at the 12-month sacrifice and thereafter. Reductions in mean body weight gain were observed in high dose group male rats throughout most of the study and in the high dose group of female rats after approximately 18 months. Conversely, there was a slight increase in the mean body weight gain for the medium level female rats from about day 21 until 21 months that was of equivocal biological significance. Increased mortality was observed in the high dose group of both sexes and the mid dose group of female rats. The cause of the decreased survival was unclear, but may have been related to the enhancement of background degenerative lesions such as chronic nephropathy. Throughout the study, male rats from the high dose group had decreased erythrocyte counts, haemoglobin concentration and haematocrit. The cause and biological significance of the haematological changes were unknown. Increased water consumption was observed in the high dose group of both sexes during the latter half of the study. Increased urine volume with concurrent decreased urine specific gravity was generally observed in the high dose group of both sexes in the last half of the study and suggested a possible alteration in kidney function. Altered urine volume and specific gravity persisted to termination in female rats only. Slight increases in absolute and relative kidney weights were also observed in the high dose group of female rats during the latter half of the study. Hepatocellular pleomorphism was observed in the high dose group of both sexes, especially the female rats, and may have contributed to increased mean liver weights observed primarily in female rats from the high dose group. Hepatocellular pleomorphism was first observed in female rats at 12 months but was not observed in male rats until the final sacrifice. Rhinitis and tracheitis were observed with greater frequency in the high dose group of male rats at 12, 18 and 24 months and in high dose group female rats at 18 months. At 24 months, rhinitis, but not tracheitis, persisted at a significantly greater frequency in high dose group female rats. The apparent no-observable-effect level (NOEL) of this study was at the lowest dose level, 0.02 g/kg/day (equivalent to 9 mg EDA/kg/day).

The effectiveness of cyclic and continuous oral clodronate therapy on bone density and markers in osteopenic postmenopausal women

Bisphosphonates have been used effectively to treat established osteoporosis and prevent postmenopausal bone loss. However, the optimal manner of its administration-whether cyclic or continuous-has not been well established. This study investigated the efficacy of cyclic and continuous oral administration of clodronate in 54 newly identified osteopenic postmenopausal women in a randomized, double-blind, crossover fashion. The participants were randomly separated into two groups. The cyclic group (n = 29) received 800 mg twice daily of oral clodronate for 2 weeks every 3 months for the first 12 months followed by placebo for the second 12 months. The continuous group (n = 25) received placebo in the first 12 months and ingested 400 mg of clodronate once daily for the second 12 months. The urinary amino-terminal (NTXtrade mark) and carboxy-terminal (CrossLapstrade mark) cross-linked fragments of type I collagen, both markers of bone resorption, showed a marked decrease (25-50%) with both regimens during the period of active treatment. In the cyclic group, the levels of these two markers increased in the second 12 months with placebo, but did not return to the baseline completely. However, bone mineral density (BMD), determined by dual-energy X-ray absorptiometry (DXA), showed no significant change of BMD at various sites after 1 year of active treatment in both groups. Thoracic and lumbar spine X-ray showed no new vertebral fracture in either group after 2 years of treatment. With the two treatment protocols in this study, oral clodronate was effective in decreasing postmenopausal bone resorption, causing no significant changes in BMD at various sites.

Proximal femoral dimension in elderly Chinese women with hip fractures in Taiwan

To investigate the relationship between proximal femoral geometry and the occurrence of hip fracture, we compared the geometry of contralateral normal hips of 120 elderly Chinese women with hip fractures, including 63 femoral neck fractures (group A) and 57 intertrochanteric fractures (group B) due to minor trauma, with that of 72 normal elderly Chinese women (group C). The mean ages for group A, B and C subjects were 77.3, 79.7 and 72.9 years, respectively. The femoral neck length (NL), neck width (NW), diameter of femoral head, femoral shaft width just below the lesser trochanter, and neck-shaft angle (theta;) were measured on the anteroposterior plain pelvic radiographs. The mean +/- SD of NL for group A was 50.4 +/- 3.3 mm; for group B, 50.6 +/- 3.1 mm; and for group C, 48.8 +/- 3.6 mm. Statistical analysis by ANOCOVA and regression showed that only NL of women with hip fractures was significantly longer than controls after correction for age, body height and weight (p <0.01). However, the difference in NL between group A and group B was not significant. By linear regression, the probability of fracture increased only with older age (p <0.001), longer NL (p <0.005) and lighter body weight (p <0.05). By logistic regression, each standard deviation increase in NL increased the risk of hip fracture (age-adjusted odds ratio 1.84; 95% CI, 1.11-3.06). The results confirm the relationship between proximal femoral geometry and the occurrence of hip fracture in elderly Chinese women in Taiwan.

Approaches to developing alternative and predictive toxicology based on PBPK/PD and QSAR modeling

Systematic toxicity testing, using conventional toxicology methodologies, of single chemicals and chemical mixtures is highly impractical because of the immense numbers of chemicals and chemical mixtures involved and the limited scientific resources. Therefore, the development of unconventional, efficient, and predictive toxicology methods is imperative. Using carcinogenicity as an end point, we present approaches for developing predictive tools for toxicologic evaluation of chemicals and chemical mixtures relevant to environmental contamination. Central to the approaches presented is the integration of physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) and quantitative structure--activity relationship (QSAR) modeling with focused mechanistically based experimental toxicology. In this development, molecular and cellular biomarkers critical to the carcinogenesis process are evaluated quantitatively between different chemicals and/or chemical mixtures. Examples presented include the integration of PBPK/PD and QSAR modeling with a time-course medium-term liver foci assay, molecular biology and cell proliferation studies. Fourier transform infrared spectroscopic analyses of DNA changes, and cancer modeling to assess and attempt to predict the carcinogenicity of the series of 12 chlorobenzene isomers. Also presented is an ongoing effort to develop and apply a similar approach to chemical mixtures using in vitro cell culture (Syrian hamster embryo cell transformation assay and human keratinocytes) methodologies and in vivo studies. The promise and pitfalls of these developments are elaborated. When successfully applied, these approaches may greatly reduce animal usage, personnel, resources, and time required to evaluate the carcinogenicity of chemicals and chemical mixtures.

Antagonistic interactions of an arsenic-containing mixture in a multiple organ carcinogenicity bioassay

Inorganic arsenic (As), 1,2-dichloroethane (DCE), vinyl chloride (VC) and trichloroethylene (TCE) are frequently identified as groundwater contaminants near hazardous waste disposal sites. While the carcinogenicity of each of these chemicals has been extensively studied individually, little information exists regarding their carcinogenic potential in combination. Therefore, we investigated the carcinogenic promoting potential of chemical mixtures containing arsenic, DCE, VC and TCE following multiple initiator administration in a multiple organ carcinogenicity bioassay (N. Ito, T. Shirai, S. Fukushima, Medium-term bioassay for carcinogens using multiorgan models, in: N. Ito, H. Sugano (Eds.), Modification of Tumor Development in Rodents, Prog. Exp. Tumor Res., 33, 41-57, Basel, Karger, 1991). Our results reveal a dose-responsive antagonistic effect of this four-chemical mixture on the development of preneoplastic hepatic lesions (altered hepatocellular foci and glutathione S-transferase pi positive foci) as well as bronchioalveolar hyperplasia and adenoma formation.

Tissue factor activity of SW-480 human colon adenocarcinoma cells is modulated by thrombin and protein kinase C activation

Expression of tissue factor (TF), a cellular initiator of the extrinsic coagulation cascade, is a feature of many malignant tumours and is intimately involved in the process of metastasis. SW-480 human colon adenocarcinoma cells responded to thrombin (1 U ml(-1)) or phorbol 12-myristate 13-acetate (PMA, 0.1 microM) with a 6.0-fold and a 7.7-fold increase in their procoagulant activity (PCA), respectively, after 4-6 h incubation in serum-free medium. The thrombin-enhanced PCA was significantly inhibited by complexing of thrombin with hirudin, or by serine protease inhibition with 3,4-dichloroisocoumarin. Both effects of thrombin and PMA on PCA in SW-480 cells were blocked by pretreatment of cells with cycloheximide or actinomycin D, indicating that the response required de novo protein and RNA synthesis. The thrombin-enhanced PCA depended on the activation of protein kinase C (PKC) as it was diminished by staurosporine and calphostin C. Moreover, stimulation of SW-480 cells by thrombin or PMA led to a significant increase in TF mRNA within 3 h as measured by the reverse-transcription PCR method, which was also dependent on the activation of PKC. The unaltered decay rate of thrombin-enhanced TF mRNA, evaluated after the addition of staurosporine, suggested that its inhibitory effect occurred at a transcription level. Our data suggest that thrombin enhances TF gene expression and protein synthesis in tumour cells in vitro via PKC activation. The induction of TF expression in tumour cells by thrombin indicates that tumour-associated PCA might have a positive-feedback effect on in vivo local propagation of thrombus by thrombin formation.