[The consistency of skeletal muscle mass measured by CT at L1 and L3 levels and the correlation of skeletal muscle density at L1 level with prognosis in dialysis patients]

Objective: To investigate the consistency of skeletal muscle mass by CT at 1st lumbar vertebrae (L1) and 3rd lumbar vertebrae (L3) levels and the correlation of skeletal muscle density (SMD) at L1 level with prognosis in dialysis patients. Methods: A total of 1 020 patients who underwent initial dialysis and had CT examination data in four centers (Zhongda Hospital Affiliated to Southeast University, the Third Affiliated Hospital of Soochow University, Taizhou People's Hospital Affiliated to Nanjing Medical University and the Affiliated Hospital of Yangzhou University) from January 2014 to December 2019 were retrospectively collected. The skeletal muscle index (SMI) and SMD at L1 and L3 CT images were measured and calculated in patients with both L1 and L3 level CT images. The consistency of SMI and SMD at L1 and L3 levels was analyzed, and the cut-off value of SMI and SMD at L1 level for predicting all-cause mortality and their correlation with the prognosis of dialysis patients were studied. Cox regression model was used to analyze the risk factors for all-cause death and cardiac death. Results: A total of 383 patients had both L1 and L3 level images, including 233 males and 150 females. The average SMD value of 16 samples (4.2%) exceeded the 95% consistency limit range (-8.71 to 7.75 HU), and the average SMI value of 15 samples (3.9%) exceeded the 95% consistency limit range (-20.45 to 9.53 HU). The optimal cut-off value of SMD at L1 level for predicting all-cause mortality was 36.46 HU and the area under curve (AUC) of receiver operating characteristic (ROC) curve was 0.658 (95%CI: 0.596-0.721, P<0.001), with the sensitivity and specificity of 83.8% and 57.5%, respectively. SMI at L1 level was not significantly associated with all-cause mortality (P=0.299). Multivariate Cox regression analysis showed that low SMD at L1 level was associated with all-cause mortality (HR=2.861, 95%CI: 1.576-5.193, P=0.001) and cardiac death (HR=3.771, 95%CI:1.462-9.724, P=0.006). Conclusions: SMD at L1 levelis consistent with SMD at L3 level and can be used to evaluate muscle mass. Low SMD is a risk factor for mortality in dialysis patients.

Adaptation and external validation of the European randomised study of screening for prostate cancer risk calculator for the Chinese population

BACKGROUND

To adapt the well-performing European Randomized Study of Screening for Prostate Cancer (ERSPC) risk calculator to the Chinese setting and perform an external validation.

METHODS

The original ERSPC risk calculator 3 (RC3) for prostate cancer (PCa) and high-grade PCa (HGPCa) was applied to a development cohort of 3006 previously unscreened Hong Kong Chinese men with initial transrectal biopsies performed from 1997 to 2015, age 50-80 years, PSA 0.4-50 ng ml^-1 and prostate volume 10-150 ml. A simple adaptation to RC3 was performed and externally validated in a cohort of 2214 Chinese men from another Hong Kong hospital. The performance of the models were presented in calibration plots, area under curve (AUC) of receiver operating characteristics (ROCs) and decision curve analyses.

RESULTS

PCa and HGPCa was diagnosed in 16.7% (503/3006) and 7.8% (234/3006) men in the development cohort, and 20.2% (447/2204) and 9.7% (214/2204) men in the validation cohort, respectively. The AUCs using the original RC3 model in the development cohort were 0.75 and 0.84 for PCa and HGPCa, respectively, but the calibration plots showed considerable overestimation. In the external validation of the recalibrated RC3 model, excellent calibration was observed, and discrimination was good with AUCs of 0.76 and 0.85 for PCa and HGPCa, respectively. Decision curve analyses in the validation cohort showed net clinical benefit of the recalibrated RC3 model over PSA.

CONCLUSIONS

A recalibrated ERSPC risk calculator for the Chinese population was developed, and it showed excellent discrimination, calibration and net clinical benefit in an external validation cohort.

Cyr61 promotes epithelial-mesenchymal transition and tumor metastasis of osteosarcoma by Raf-1/MEK/ERK/Elk-1/TWIST-1 signaling pathway

Background

Osteosarcoma is the most common primary malignant tumor in children and young adults, and its treatment requires effective therapeutic approaches because of a high mortality rate for lung metastasis. Epithelial to mesenchymal transition (EMT) has received considerable attention as a conceptual paradigm for explaining the invasive and metastatic behavior during cancer progression. The cysteine-rich angiogenic inducer 61 (Cyr61) gene, a member of the CCN gene family, is responsible for the secretion of Cyr61, a matrix-associated protein that is involved in several cellular functions. A previous study showed that Cyr61 expression is related to osteosarcoma progression. In addition, Cyr61 could promote cell migration and metastasis in osteosarcoma. However, discussions on the molecular mechanism involved in Cyr61-regulated metastasis in osteosarcoma is poorly discussed.

Results

We determined that the expression level of Cyr61 induced cell migration ability in osteosarcoma cells. The Cyr61 protein promoted the mesenchymal transition of osteosarcoma cells by upregulating mesenchymal markers (TWIST-1 and N-cadherin) and inhibiting the epithelial marker (E-cadherin). Moreover, the Cyr61-induced cell migration was mediated by EMT. The Cyr61 protein elicited a signaling cascade that included αvβ5 integrin, Raf-1, mitogen-activated protein kinase (MEK), extracellular signal-regulated kinase (ERK), and Elk-1. The reagent or gene knockdown of these signaling proteins could inhibit Cyr61-promoted EMT in osteosarcoma. Finally, the knockdown of Cyr61 expression obviously inhibited cell migration and repressed mesenchymal phenotypes, reducing lung metastasis.

Conclusion

Our results indicate that Cyr61 promotes the EMT of osteosarcoma cells by regulating EMT markers via a signal transduction pathway that involves αvβ5 integrin, Raf-1, MEK, ERK, and Elk-1.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-4598-13-236) contains supplementary material, which is available to authorized users.

Hyperthermia induces apoptosis through endoplasmic reticulum and reactive oxygen species in human osteosarcoma cells

Osteosarcoma (OS) is a relatively rare form of cancer, but OS is the most commonly diagnosed bone cancer in children and adolescents. Chemotherapy has side effects and induces drug resistance in OS. Since an effective adjuvant therapy was insufficient for treating OS, researching novel and adequate remedies is critical. Hyperthermia can induce cell death in various cancer cells, and thus, in this study, we investigated the anticancer method of hyperthermia in human OS (U-2 OS) cells. Treatment at 43 °C for 60 min induced apoptosis in human OS cell lines, but not in primary bone cells. Furthermore, hyperthermia was associated with increases of intracellular reactive oxygen species (ROS) and caspase-3 activation in U-2 OS cells. Mitochondrial dysfunction was followed by the release of cytochrome c from the mitochondria, and was accompanied by decreased anti-apoptotic Bcl-2 and Bcl-xL, and increased pro-apoptotic proteins Bak and Bax. Hyperthermia triggered endoplasmic reticulum (ER) stress, which was characterized by changes in cytosolic calcium levels, as well as increased calpain expression and activity. In addition, cells treated with calcium chelator (BAPTA-AM) blocked hyperthermia-induced cell apoptosis in U-2 OS cells. In conclusion, hyperthermia induced cell apoptosis substantially via the ROS, ER stress, mitochondria, and caspase pathways. Thus, hyperthermia may be a novel anticancer method for treating OS.

Current management practice for bladder cancer in Hong Kong: a hospital-based cross-sectional survey

OBJECTIVES

To examine current practice in the management of bladder cancer in Hong Kong government and private hospitals.

DESIGN

Cross-sectional survey.

SETTING

All government hospitals and the major private institutions in Hong Kong, which provide urological services.

PARTICIPANTS

Urologists responding to an anonymous, self-administered, web-based questionnaire regarding practices in smoking cessation, treatment of non-muscle invasive bladder cancer and muscle invasive bladder cancer, and research into bladder cancer.

RESULTS

Of the 29 urologists from 11 government hospitals and eight private institutions who were invited, 18 from 11 (100%) government hospitals and seven from six (75%) private institutions responded, which amounted to an 86% response rate. In all, 88% of the respondents seldom or never referred their bladder cancer patients to smoking cessation programmes. Hong Kong urologists showed good compliance in the management of non-muscle invasive bladder cancer according to international guidelines. There was great variation with regard to regimens for maintenance of intravesical immunotherapy. There was underuse of perioperative systemic chemotherapy, despite wide acceptance of this practice; fewer than 10% of the patients received neo-adjuvant and adjuvant systemic chemotherapy for the treatment of muscle invasive bladder cancer. Of the surveyed urologists, 80% expressed an inadequacy of resources for bladder cancer research and 96% agreed that a local inter-hospital bladder cancer database was needed.

CONCLUSIONS

This study demonstrated great diversity in the use of intravesical immunotherapy, perioperative systemic chemotherapy, and surgical treatment of bladder cancer among urology service providers. There is a need for clear recommendations in these areas.

Transforming growth factor alpha promotes osteosarcoma metastasis by ICAM-1 and PI3K/Akt signaling pathway

Osteosarcoma is the most common primary malignancy of bone and is characterized by a high malignant and metastatic potential. Transforming growth factor alpha (TGF-α) is classified as the EGF (epidermal growth factor)-like family, which is involved in cancer cellular activities such as proliferation, motility, migration, adhesion and invasion abilities. However, the effect of TGF-α on human osteosarcoma is largely unknown. We found that TGF-α increased the cell migration and expression of intercellular adhesion molecule-1 (ICAM-1) in human osteosarcoma cells. Transfection of cells with ICAM-1 siRNA reduced TGF-α-mediated cell migration. We also found that the phosphatidylinositol 3'-kinase (PI3K)/Akt/NF-κB pathway was activated after TGF-α treatment, and TGF-α-induced expression of ICAM-1 and cell migration was inhibited by the specific inhibitors and siRNAs of PI3K, Akt, and NF-κB cascades. In addition, knockdown of TGF-α expression markedly decreased cell metastasis in vitro and in vivo. Our results indicate that TGF-α/EGFR interaction elicits PI3K and Akt activation, which in turn activates NF-κB, resulting in the expression of ICAM-1 and contributing the migration of human osteosarcoma cells.

Age, tumour stage, and preoperative serum albumin level are independent predictors of mortality after radical cystectomy for treatment of bladder cancer in Hong Kong Chinese

OBJECTIVES

To evaluate the association between patient age, other clinical factors and mortality following radical cystectomy for treatment of bladder cancer.

DESIGN

Historical cohort study.

SETTING

A urology unit in Hong Kong.

PATIENTS

The outcomes of 117 patients who had radical cystectomies performed in one urological unit from 2003 to 2011 were reviewed. Demographic and perioperative data, including tumour stage, Charlson Comorbidity Index, and preoperative serum albumin levels were retrieved from computerised medical records. Risk factors for 30-day mortality, and cancer-specific, other-cause, and overall death rates at 5 years were calculated. The data were subsequently stratified and analysed according to age.

RESULTS

Of the 117 patients, 83 (71%) were aged 75 years or below. The mean follow-up duration was 31 (standard deviation, 29) months. Age, tumour stage, and preoperative serum albumin level, but not the Charlson Comorbidity Index, were found to be predictors of survival following radical cystectomy. The overall 30-day mortality rate was 3% in the full sample, 1% in patients aged 75 years or below, and 10% in patients aged over 75 years. There was no significant difference in 5-year cancer-caused mortalities between patients aged 75 years or below and those aged over 75 years (33% vs 33%, P=0.956). In patients older than 75 years, the 5-year other-cause and overall mortality rates were 47% and 80%, respectively; such rates were higher than those for younger patients (13% and 46%, respectively).

CONCLUSION

Age, tumour stage, and preoperative serum albumin level were predictors of survival after radical cystectomy. Non-cancer-related death played a crucial role in the overall mortality rate in elderly patients having radical cystectomy for bladder cancer.

Reliability and validity of the overactive bladder symptom score in Hong Kong Chinese

OBJECTIVE

To validate the Hong Kong Chinese translation of the Overactive Bladder Symptom Score questionnaire (OABSS-HKC).

DESIGN

Cross-sectional study.

SETTING

Five urology clinics of different regional hospitals in Hong Kong.

PARTICIPANTS

The Overactive Bladder Symptom Score questionnaire was translated and culturally adapted for Hong Kong Chinese, according to the Principles of Good Practice for the Translation and Cultural Adaptation Process for Patient-Reported Outcomes Measures. Chinese-speaking patients with overactive bladder symptoms were recruited from five urology clinics. The patients completed the OABSS-HKC, a 3-day micturition diary, International Prostate Symptom Scores, and the Patient Perception of Bladder Condition questionnaires (visit 1), and again after a 2-week interval (visit 2). Test-retest reliability was evaluated by the intraclass correlation coefficient and weighted Kappa coefficient. The relationship between OABSS-HKC total scores and items in the comparison measures was evaluated using Spearman's correlation coefficients.

RESULTS

The OABSS-HKC was successfully translated and culturally adapted. Fifty-one patients completed the validation study. A high level of reliability was observed between the OABSS-HKC total score answered at visit 1 and 2 for all subjects (intraclass correlation coefficient, 0.82) and among the four items answered (weighted Kappa coefficients, 0.57-0.75). The OABSS-HKC total score correlated significantly with numbers of micturitions, incontinence and urgency episodes recorded in the 3-day micturition diary, as well as the total International Prostate Symptom Scores and the Patient Perception of Bladder Condition score. However, the OABSS-HKC total score was not significantly associated with nocturia episodes, total voided volume, or number of pads used.

CONCLUSIONS

The OABSS-HKC total scores are reliable and moderately valid for the quantitative evaluation of overactive bladder symptoms in Hong Kong Chinese-speaking adults.

CCN4 induces IL-6 production through αvβ5 receptor, PI3K, Akt, and NF-κB singling pathway in human synovial fibroblasts

Introduction

Osteoarthritis (OA) is the most common degenerative joint disease that is involved in the degradation of articular cartilage. The exact etiology of OA is not completely understood. CCN4 is related to up-regulation in the cartilage of patients with osteoarthritis. Previous studies have shown that CCN4 might be associated with the pathogenesis of OA, but the exact signaling pathways in CCN4-mediated IL-6 expression in synovial fibroblasts (SF) are largely unknown. Therefore, we explored the intracellular signaling pathway involved in CCN4-induced IL-6 production in human synovial fibroblast cells.

Methods

CCN4-induced IL-6 production was assessed with quantitative real-time qPCR and ELISA. The mechanisms of action of CCN4 in different signaling pathways were studied by using Western blotting. Neutralizing antibodies of integrin were used to block the integrin signaling pathway. Luciferase assays were used to study IL-6 and NF-κB promoter activity. Immunocytochemistry was used to examine the translocation activity of p65.

Results

Osteoarthritis synovial fibroblasts (OASFs) showed significant expression of CCN4 and the expression was higher than in normal SFs. OASF stimulation with CCN4 induced concentration- and time-dependent increases in IL-6 production. Pretreatment of OASFs with αvβ5 but not α5β1 and αvβ3 integrin antibodies reduced CCN4-induced IL-6 production. CCN4-mediated IL-6 production was attenuated by PI3K inhibitor (LY294002 and Wortmannin), Akt inhibitor (Akti), and NF-κB inhibitor (PDTC and TPCK). Stimulation of cells with CCN4 also increased PI3K, Akt, and NF-κB activation.

Conclusions

Our results suggest that CCN4 activates αvβ5 integrin, PI3K, Akt, and NF-κB pathways, leading to up-regulation of IL-6 production. According to our results, CCN4 may be an appropriate target for drug intervention in OA in the future.

Late recurrent seminoma: 18 years after bilateral orchidectomy in patient with bilateral stage one testicular seminoma

Late recurrence of stage I seminoma is an uncommon event. We reported a patient with seminoma recurred 18 years after the initial bilateral orchidectomy for bilateral stage I seminoma. He was on surveillance after the initial treatment and remained disease free for 18 years. He then presented with liver mass and diagnosed as recurrent seminoma. Systemic chemotherapy and subsequent hepatectomy for residual hepatic tumour mass were performed and the disease was cleared. The incidence and management of the late recurrence of seminoma would be discussed.

Long-term outcome of patients with a successful trial without catheter, after treatment with an alpha-adrenergic receptor blocker for acute urinary retention caused by benign prostatic hyperplasia

OBJECTIVE

To perform a retrospective review of long-term outcome for patients with a first episode of acute urinary retention (AUR) who could void successfully after the initial trial without catheter (TWOC) after treatment with an alpha-adrenergic receptor blocker (AR blocker).

METHODS

The records of 248 patients who presented with a first episode of AUR secondary to benign prostatic hyperplasia (BPH) and who could void successfully after the initial TWOC following treatment with an AR blocker were reviewed during the period January 1998 to December 2001. The characteristics of the patients and the subsequent outcomes were recorded. The primary outcome assessed was failed medical treatment within the five-year follow-up period. Factors correlated with the primary outcome were also assessed.

RESULTS

For these 248 patients, the median follow-up time was 33.0 months (range 0-96 months). The percentage of patients with failed medical treatment at 6, 12, 24, and 60 months was 11.6, 14.3, 28.4, and 50.5%, respectively. Multivariate analysis indicated that only a prostate size >50 ml and serum prostate specific antigen (PSA) level during AUR >10 ng/dl were significant predictors of subsequent requirement for surgical intervention after a successful TWOC.

CONCLUSIONS

Although AR blockers increased the success rate of TWOC, approximately half of the patients in this study still required additional intervention within five years. By using appropriate selection criteria, such as a large prostate size (>50 ml) or high serum PSA level during AUR (>10 microg/l), patients who are at greater risk of TWOC failure can be identified, and earlier surgical intervention can be offered to them.

Skin and soft tissue infection caused by non-tuberculous mycobacteria

SETTING

A medical centre in Taipei, Taiwan.

OBJECTIVE

To investigate the trend and characteristics of patients with non-tuberculous mycobacteria (NTM) related skin and soft tissue infection.

DESIGN

A total of 63 patients with culture-proven diseases were identified from January 1997 to December 2004. The medical records of all patients were reviewed.

RESULTS

Twenty-seven patients were infected with rapidly growing mycobacteria (RGM), 19 with Mycobacterium marinum, six with M. avium complex (MAC), five with M. kansasii and six with other species. Most patients presented with a protracted cutaneous lesion without systemic symptoms, and two thirds of the patients had a history of exposure. Seventy-three per cent of the lesions involved the extremities. Underlying illness with suppressed immunity was documented in 30.2% of the patients, and was most prevalent in patients with MAC (100%) and M. kansasii (60%). Of the patients, 62% underwent at least one surgical intervention, and 77.8% received treatment with different antimicrobial combinations. Most patients (86%) recovered completely. Granulomatous inflammation was found in 88.9% of biopsied tissue associated with M. marinum infection, 31.8% with RGM and 25.0% with MAC.

CONCLUSION

A combination of surgery and antimicrobials cured most patients with microbiologically proven localised NTM skin and soft tissue infection.

An osteomyocutaneous transplantation model on the rat

To replace the complex and time-consuming procedure of limb transplantation, we developed a new osteomyocutaneous model that excluded the function but retained all the tissue components of the limb. Ten vascularized grafts from five donor hindlimbs were contralaterally transplanted to 10 syngeneic recipients' inguinal region. The graft of this model is composed of complete tibia and fibula and partial muscle and skin of the crus. The operative time was 145.3 +/- 9.1 minutes with the harvesting time of 49.7 +/- 5.8 minutes and the warm ischemia time of 65.4 +/- 6.0 minutes. The transplantation procedure of this model takes significantly less time and is less stressful to the animals than the previous whole limb transplantation model. This model is suitable for the studies of limb or composite tissue transplantation if functional recovery is not the main concern.

Embolisation of a renal artery pseudoaneurysm in a patient with renal malrotation and chronic aortic dissection

INTRODUCTION

Renal artery pseudoaneurysms may arise as a complication of percutaneous nephrolithotomy (PCNL). Prompt recognition and treatment is essential to arrest haemorrhage which may be life threatening.

CLINICAL PICTURE

A patient with chronic aortic dissection and malrotated right kidney underwent PCNL for right renal calculus. He developed delayed gross haematuria.

TREATMENT

Angiography showed a pseudoaneurysm arising from one of two right renal arteries, which in turn arose from the false lumen of the aortic dissection. The supplying artery was successfully embolised.

CONCLUSION

Renal artery pseudoaneurysms can be successfully treated with prompt angiography and embolisation, even in the presence of renal malrotation and aortic dissection.

Mutational spectrum induced by acetaldehyde in the HPRT gene of human T lymphocytes resembles that in the p53 gene of esophageal cancers

As the primary metabolite of alcohol, acetaldehyde (AA) may be responsible for many pathological effects related to consumption of alcohol, such as esophageal cancer. The spectrum of p53 mutations in esophageal tumors is indicative of the involvement of exogenous agents, such as tobacco smoke. There is, however, no experimental proof for the involvement of alcohol as data on mutational spectrum induced by AA in human genes is completely lacking. The aim of this study is to investigate whether AA leaves mutational fingerprint in the HPRT reporter gene in human peripheral T cells. Pre-existing in vivo HPRT mutants were removed from PHA-stimulated T lymphocytes before in vitro treatment with 2.4 mM AA for 24 h. Following cell growth to allow mutation expression, independent 6-thioguanine-resistant mutants were selected from large numbers of subcultures showing a 3-fold induction of mutant frequency on average. A total of 73 induced and 36 spontaneous mutants were found to carry a missense, nonsense, frameshift or splice mutation. Base substitutions were identified in the coding or splicing sequences of 55 induced and 26 control mutants. The induced base changes were mainly G > A transition (40%, G on non-transcribed strand) followed by A > T transversions (14.5%, A on non-transcribed strand). The control mutants had significantly (P = 0.04) less G > A transition (15.4%) and completely lacked A > T transversions. We also identified 5'-AGG-3' or 5'-AAG-3' as potential target sequences for AA-induced G > A transitions. This specific mutational spectrum induced by AA is consistent with the known formation and persistency of N(2)-ethyl-2'-guanosine adduct and with the predominance of G > A transitions and mutations at A:T base pairs in the p53 gene of esophageal tumors. We conclude that AA may be involved in the pathogenesis of esophageal cancer.

Extra-articular deformity in distal radial fractures treated by external fixation

OBJECTIVE

To determine the radiographic outcome in fractures of the distal radius treated with closed reduction and external fixation.

DESIGN

A retrospective study.

SETTING

The orthopedic department of National Taiwan University Hospital.

PATIENTS

Eighty-five consecutive patients (36 female, 49 male), average age 48 years, with fractures of the distal radius seen between March 1995 and June 1998.

INTERVENTIONS

Closed reduction and external fixation of fractures, followed up by good-quality posteroanterior and lateral radiographs to evaluate healing.

MAIN OUTCOME MEASURES

Radial height, radial inclination and volar tilt were measured on radiographs obtained initially, immediately postoperatively and at the time of removal of external fixation. Data were analyzed by the t-test.

RESULTS

Immediately after reduction and fixation, there was a significant improvement in the measurements of radial height and radial inclination. This improvement was gradually lost and height and inclination were significantly decreased at the time the external fixation device was removed. External fixation did not improve the volar tilt.

CONCLUSION

External fixation is a popular method to improve the reduction of osseous deformity but cannot effectively protect comminuted distal radial fractures from loss of reduction, which may be associated with shortening and redisplacement.

XPD exon 10 and 23 polymorphisms and DNA repair in human skin in situ

Forty-four Finnish volunteers who were previously studied with regard to the repair rate of UV-specific cyclobutane pyrimidine dimers in the skin were genotyped for XPD polymorphisms at codons 312 (exon 10 G-->A, Asp-->Asn) and 751 (exon 23 A-->C, Lys-->Gln). The repair rate was measured at 24 h for two different cyclobutane dimers. The data did not show consistent XPD genotype-specific differences in DNA repair rates among all subjects. The combined exon 10 AA and exon 23 CC genotype was associated with an approximately 50% depression of repair rate but this was of borderline statistical significance. However, the exon 23 C allele was associated with depressed repair among subjects aged 50 years or older and the result was consistent with both dimers.

Implementation and evaluation of a multifunctional telemedicine system in NTUH

In this article, we proposed a multifunctional telemedicine system supporting both telediagnosis and teleconsultation services. We attempted not only to insure that the implementation of this system satisfied most requirements, but also to evaluate the impact of the system. With regard to system architecture, we designed a unified multimedia database to store all types of data and used two kinds of network (ATM and ISDN) for different possible applications. As for data transmission, the REFRESH and PREFETCH mechanisms were implemented to enhance data transfer efficiency. A total of 1107 consultations employing the telemedicine system were performed during the past 3 years. This technology was used most frequently for radiology consultation (32.7%, n = 362) and ultrasonic examination (19.5%, n = 216). An evaluation of the impact on diagnosis (507 valid cases) indicated that the diagnosis in 80 cases (15.78%) were altered on the basis of second opinions from a medical center; and the number of patients transferred to the medical center was reduced from 24 (4.7%) to eight cases. Most of the rural-site physicians (97%) thought that they did benefit from specialists' experience and knowledge via the telemedicine system. Based on 431 valid questionnaires, the number of the patients with confidence in the telemedicine system at their local healthcare center increased from 72.6% to 87.5%. Overall, more than 90% of patients and physicians believed that the system was valuable and provided satisfactory services.

Bending strength and holding power of tibial locking screws

The bending strength and holding power of two types of specially designed tibial locking devices, a both-ends-threaded screw and an unthreaded bolt, were studied and compared with four types of commercially available tibial interlocking screws: Synthes, Howmedica, Richards, and Osteo AG. To test bending strength, the devices were inserted into a high molecular weight polyethylene tube and loaded at their midpoint by a materials testing machine to simulate a three point bending test. Single loading yielding strength and cyclic loading fatigue life were measured. To test holding power, the devices were inserted into tubes made of polyurethane foam, and their tips were loaded axially to measure pushout strength. The devices were tested with two different densities of foam materials and two different sizes of pilot holes. Insertion torque and stripping torque of the screws were measured first. Pushout tests were performed with each screw inserted with a tightness equal to 60% of its stripping torque. Test results showed that the yielding strength and the fatigue life were related closely to the inner diameter of the screws. The stripping torque predicted the pushout strength more reliably than did the insertion torque. All tested devices showed greater holding power in the foam with the higher density and with the smaller pilot holes. The both-ends-threaded screw had the highest pushout strength and a satisfactory fatigue strength. The unthreaded bolt had the highest fatigue strength but only fair holding power. Clinical studies of the use of these two types of locking devices are worthwhile.

Differential interactions between GSTM1 and NAT2 genotypes on aromatic DNA adduct level and HPRT mutant frequency in lung cancer patients and population controls

We have studied the influence of GSTM1 and NAT2 genotypes on aromatic DNA adduct level (AL) and HPRT mutant frequency (MF) in smokers with newly diagnosed lung cancer and matched population controls. AL was analyzed in relation to genotypes in 170 cases and 144 controls (113 current/recent smokers and 201 former/never smokers), and MF in 157 cases and 152 controls (155 ever smokers and 154 never smokers). Both genotypes exhibited the a priori expected effects on AL and MF among controls only, especially among smoking controls [significantly lower pack-years (a pack-year is defined as 1 pack of cigarettes/day for 1 year) than among cases]. Among the 42 currently smoking controls, the NAT2 slow genotype [odds ratio (OR), 7.5; 95% confidence interval (CI), 1.5-38.4], in particular in combination with the GSTM1 null genotype (OR, 19.3, 95% CI, 1.1-338.6 for null/slow versus positive/rapid) was strongly associated with high AL. The null/slow combination was also significantly associated with high MF among ever smokers (cases and controls pooled) with lower pack-years (OR, 3.7; 95% CI, 1.3-10.7 versus all of the other genotypes; OR, 5.1; 95% CI, 1.2-22.4 versus positive/rapid). In contrast, an antagonistic gene-gene interaction was seen among smoking cases for both AL and MF. Only currently smoking cases with the combined GSTM1 null and NAT2 rapid genotype showed a positive correlation between InAL and InMF (r, 0.64; P = 0.1), and an increase of AL with both age and daily cigarette use. This genotype combination was also associated with high MF among ever-smoking cases (OR, 4.0; 95% CI, 0.9-17.7 versus positive/rapid). There was a significant interaction between NAT2 genotype and pack-years of smoking among cases, so that the rapid genotype was associated with high MF among ever-smoking cases diagnosed at higher pack-years, whereas the slow genotype was associated with high MF at lower pack-years. These findings suggest that the influence of NAT2 genotype on AL and MF and its interaction with GSTM1 genotype may be dose dependent. The NAT2 slow genotype, in particular when combined with the GSTM1 null genotype, may confer increased susceptibility to adduct formation, gene mutation, and lung cancer when the smoking dose is low.

Glutathione S-transferase T1-null genotype interacts synergistically with heavy smoking on lung cancer risk

We studied the influence of genotype for glutathione S-transferase T1 (GSTT1) on susceptibility to lung cancer among 184 Swedish lung cancer patients (88 never-smokers and 96 ever-smokers) and 162 matched population controls (79 never-smokers and 83 ever-smokers), with special emphasis on gene-environment interactions. Cases had significantly lower frequency of the GSTT1-null genotype than that of controls among never-smokers (4.6 vs. 16.5%, P = 0.02), whereas the frequencies were very close to each other among smokers (7.4 vs. 7.2%). Cases with high packyears of smoking, however, had a significantly higher frequency of the GSTT1-null genotype compared to that of cases with low packyears (18.3 vs. 5.6%, P = 0.005). Adjusted for age and gender, the GSTT1-null genotype appeared to be protective against lung cancer among never-smokers (odds ratio [OR] = 0.2, 95% confidence interval [CI] = 0.07-0.7), although it was associated with an increased risk for lung cancer among smokers (OR = 2.1, 95% CI = 0.8-5.9), mainly attributed to the group of heavy smokers (>23 packyears; OR = 3.5, 95% CI = 0.7-17.3). Heavy smoking conferred a threefold increased risk for lung cancer (OR = 2.6, 95% CI = 1.3-5.0) among GSTT1-positive individuals, but a ninefold increased risk when combined with the GSTT1-null genotype (OR = 9.3, 95% CI = 1.9-46.3, relative to GSTT1-positive light smokers). This joint effect was further demonstrated by a positive interaction between the GSTT1-null genotype and packyears of smoking. The risk of lung cancer increased steeply with increasing packyears among GSTT1-null smokers, whereas no such effect was seen among GSTT1-positive smokers. We conclude that the GSTT1-null genotype may strengthen the effect of heavy smoking on lung cancer risk.

Unreamed locked tight-fitting nailing for acute tibial fractures

OBJECTIVES

Treatment of tibial fractures by unreamed locked nailing with loose-fitting nails has previously been shown to be associated with a low union rate and high implant failure rate. This report describes the authors' experience in using tight-fitting nails that were relatively larger than loose-fitting nails.

DESIGN

Prospective cohort study.

SETTING

University medical center.

PATIENTS

Forty-eight consecutive patients with fifty-two tibial fractures (excluding open IIIC fractures and those with bone loss) were studied: thirty-four men and fourteen women, with a mean age of 38 years. There were twenty-five closed fractures, nine Type I, eight Type II, four Type IIIA, and six Type IIIB open fractures.

INTERVENTION

Unreamed nailing with tight-fitting nails using the Russell-Taylor system.

OUTCOME MEASURES

Union rate, time to union, complication rate, and functional recovery, as well as nailing time, hospital time, and crutch-walking time were recorded.

RESULTS

Union occurred in forty-eight of fifty-two fractures (92%) with a mean time to union of 18.2 weeks. Compartment syndrome occurred in three patients. Deep infection occurred in one Type II and one Type IIIB open fracture. Four fractures required additional exchange nailing or bone grafting to achieve union: one Type II, one Type IIIA, and two Type IIIB open fractures. Three malalignments resulted from operative technical error. The rate of both intraoperative bony split and screw breakage was 3.8% (2 of 52), but neither complication interfered with fracture healing. Recovery of joint motion was essentially normal in those patients without knee or ankle injury.

CONCLUSIONS

Unreamed locked nailing with tight-fitting nails can produce satisfactory clinical results for acute tibial fractures. It has the advantages of technical simplicity and an acceptable risk of implant failure.

Rotational alignment of humerus after closed locked nailing

OBJECTIVE

Rotational malalignment that may happen during closed nailing of humeral fractures is, to date, an unexplored area of investigation. The purpose of this study was to examine the effect of arm position during surgery on humeral rotational alignment and the effect of this alignment on shoulder motion and function.

METHODS

Thirty patients with eventual fracture healing after closed humeral locked nailing were retrospectively studied: 15 had retrograde nailing; 15, antegrade. Retrograde nailing was performed with the patient in a decubitus position and with the upper arm anteriorly flexed and the forearm perpendicular to the operating table. Antegrade nailing was performed with the patient in a semisitting position and with the upper arm in the so-called resting position. The humeral retroversion angle as measured by computed tomographic scan, range of shoulder rotation, and Neer score of the shoulder for the fractured and the intact humeri were determined, and the discrepancy (i.e., value for the intact subtracted from that for the fractured) between the two was noted. To test the effect on alignment of positioning during retrograde nailing, we similarly determined retroversion angles for another 15 patients treated in a supine resting position.

RESULTS

Between antegrade nailing and retrograde nailing in decubitus position, there was a significant difference in the mean discrepancies for the retroversion angles and the range of external rotation of the shoulder in the neutral and abduction positions, but no significant difference for internal rotation of the shoulder and Neer score. Between antegrade nailing and retrograde nailing in supine resting position, there was no significant difference in the mean discrepancy for the retroversion angle.

CONCLUSION

Positioning of the arm may significantly affect humeral rotational alignment and range of motion during closed nailing. Until a reliable method for intraoperative measurement of humeral rotation is devised, we recommend that closed nailing of humeral shaft fractures be performed with the patient's upper arm in the resting position shown in this study.

Mycobacterial infection of the upper extremities

BACKGROUND AND PURPOSE

Mycobacterial infection of the upper extremities is extremely rare. To make an early accurate diagnosis is often difficult, and the treatment is, therefore, frequently delayed in clinical practice. This paper describes the diagnosis and treatment of mycoabacterial infection of the upper extremities in a series of patients treated at National Taiwan University Hospital.

METHODS

The medical records of 15 patients with mycobacterial infection of the upper extremities treated between 1985 and 1998 were retrospectively analyzed. The diagnosis of mycobacterial infection was established by positive culture results, the presence of acid-fast bacilli, or characteristic histopathologic findings.

RESULTS

Mycobacterial infection was suspected on initial examination in only two patients. The duration between the onset of symptoms and correct diagnosis averaged 37.5 months (range, 3 wk to 209 mo). The involved sites of mycobacterial infection included the wrist in nine patients, the elbow in two, the hand in two, the humerus in two, the forearm in one, and the shoulder in one. Three patients suffered from multifocal musculoskeletal mycobacterial infection. Microbiologic studies identified Mycobacterium tuberculosis in four patients and nontuberculous mycobacteria (NTM) in four. Characteristic histopathologic findings of mycobacterial infection including caseation, granulomatous inflammation, eosinophilic epithelioid cells, Langhan's giant cells, and lymphocytic aggregates were noted in all 15 patients. All patients received chemotherapy and 14 patients underwent surgical treatment. The mean duration of follow-up was 46 months (range, 15-97 months). Treatment failed in two of the patients with multifocal NTM infection and in one patient whose mycobacterial infection was identified by histopathology.

CONCLUSIONS

Mycobacterial infection should be included in the differential diagnosis of infection of the upper extremities. Treatment failures are more frequent in patients with multifocal NTM infection.

Ipsilateral distal radius and scaphoid fractures

Simultaneous fractures of the distal radius and scaphoid are uncommon. Previous reports have outlined a variety of treatment methods for this condition. We describe the results in eight patients with simultaneous fractures of the distal radius and scaphoid, who were treated at National Taiwan University Hospital from 1987 to 1998. Treatments for the distal radius fractures included pin-in-cast in one patient, casting in one, external fixation in one, external fixation after pinning in three, and open reduction with internal fixation in two. All scaphoid fractures occurred at the scaphoid waist, and were treated with long-arm thumb spica in three patients, Herbert screw fixation in two, and percutaneous pinning in three. All of the fractures united, and none of the patients developed scaphoid avascular necrosis. One patient suffered from superficial radial nerve injury during external fixation. The functional results of the wrist were good in five patients and fair in three. To prevent the possible over-distraction of the scaphoid fracture, fixation of the scaphoid should be performed if a distraction force is to be applied during the treatment of the distal radius fracture. If no distraction force is to be applied, a thumb spica may provide adequate fixation for the scaphoid fracture.

Hydrogen peroxide induced mutations at the HPRT locus in primary human T-lymphocytes

Reactive oxygen species (ROS) produced by intracellular metabolism are believed to contribute to spontaneous mutagenesis in somatic cells. Hydrogen peroxide (H(2)O(2)) has been shown to induce a variety of genetic alterations, probably by the generation of hydroxyl radicals via the Fenton reaction. The kinds of DNA sequence alterations caused by H(2)O(2) in prokaryotic cells have been studied extensively, whereas relatively little is known about the mutational spectrum induced by H(2)O(2) in mammalian genes. We have used the T-cell cloning assay to study the ability of H(2)O(2) to induce mutations at the hypoxanthine guanine phosphoribosyltransferase (HPRT) locus in primary human lymphocytes. Treatment of cells for 1 h with 0.34-1.35 mM of H(2)O(2) caused a dose dependent decrease of cell survival and increase of the HPRT mutant frequency (MF). After 8 days of expression time, the highest dose of H(2)O(2) caused a 5-fold increase of MF compared to the untreated control cells. Mutant clones were collected and the genomic rearrangements at the T-cell receptor (TCR) gamma-locus were studied to identify independent mutations. RT-PCR and DNA sequencing was used to identify mutations in the HPRT coding region. Due to a relatively high frequency of sibling clones, only six independent mutations were obtained among the controls, and 20 among the H(2)O(2) treated cells. In both sets, single base pair substitutions were the most common type of mutation (5/6 and 13/20, respectively), with a predominance of transitions at GC base pairs, which is also the most common type of HPRT mutation in T-cells in vivo. Among the single base pair substitutions, five were new mutations not previously reported in the human HPRT mutation database. Overall, the kinds of mutation occurring in T-cells in vivo and H(2)O(2) treated cells were similar, albeit the number of mutants was too small to allow a meaningful statistical comparison. These results demonstrate that H(2)O(2) is mutagenic to primary human T-lymphocytes in vitro and induces mutations of the same kind that is observed in the background spectrum of HPRT mutation in T-cells in vivo.

Mutational spectra at the hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus in T-lymphocytes of nonsmoking and smoking lung cancer patients

Molecular analysis of mutations at the hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus in peripheral blood T-lymphocytes can provide information on mechanisms of somatic in vivo mutation in populations exposed to exogenous carcinogens and in individuals with inherent susceptibility to cancer and other diseases. To study possible mutational changes associated with smoking as a risk factor for lung cancer, we analyzed HPRT mutations in T-cells of newly diagnosed, nonsmoking and smoking lung cancer patients before treatment. Reverse transcriptase polymerase chain reaction (RT-PCR) and DNA sequencing methods were used to identify 146 independent mutations, 73 each from 32 nonsmoking and 31 smoking cases. In 35 T-cell mutants, the HPRT cDNA showed loss of an entire exon, indicating a splicing mutation. Among the remaining 111 fully characterized mutations in the coding region, single base pair (bp) substitutions predominated with 79% (48/61) in nonsmokers and 90% (45/50) in smokers. Frameshift and small deletion (1-24 bp) mutations were found in 18 mutants. The distribution of base pair substitutions was nonrandom, with significant clustering at previously identified hotspot positions 143, 197 and 617 in the HPRT coding sequence (P< or =0.008). One additional hotspot, GC-->TA at position 606, was observed only in smokers (P=0.006). The frequency of GC>TA transversions was higher in smokers (13%) than in nonsmokers (6%). Conversely, smokers had a lower frequency of GC>AT transitions (24%) than nonsmokers (35%). This smoking-associated shift of the HPRT mutational spectrum, although not statistically significant, is consistent with the in vitro mutagenicity of benzo(a)pyrene (BaP), a prominent carcinogen of tobacco smoke, and with known differences in the TP53 mutational spectrum in lung tumors of smokers and nonsmokers. Among nonsmokers, the HPRT mutational spectra in healthy population controls and lung cancer patients were similar, but there was a marginally significant difference (P=0.07) in the distribution of base pair substitutions between smoking controls and patients. These results suggest that (i) general mechanisms of somatic mutagenesis in individuals with possible predisposition to cancer (e.g. nonsmoking lung cancer patients) are not different from those in normal healthy individuals, and (ii) the HPRT gene in T-cells is a useful reporter locus for smoking-associated somatic in vivo mutations occurring early in lung cancer development.

Treatment of humeral shaft delayed unions and nonunions with humeral locked nails

OBJECTIVE

To report experience with use of humeral locked nails in treating humeral delayed unions and nonunions. The following techniques yielded encouragingly good results: static locking, short-to-long segment nailing, bone grafting, fracture compression, and minimal surgical trauma.

DESIGN AND METHODS

A total of 41 consecutive patients with 13 delayed unions and 28 nonunions were treated with humeral locked nails. Delay from trauma to surgery averaged 4.2 months for delayed union and 15.5 months for nonunion. The average age of patients was 50.2 years; average follow-up time was 23.2 months. There were 7 proximal-third fractures, 21 middle-third fractures, and 13 distal-third fractures. The antegrade approach was used for 13 fractures and retrograde for 28. Open nailing was performed in 39 fractures and closed nailing in 2. If the fracture motion was still present after nail insertion, axial compression of the fracture site was specially applied. Bone grafting was performed in the fractures with open nailing. Thirty-four fractures were nailed with 8-mm nails, and 7 fractures were nailed with 7-mm nails.

RESULTS

With a single operation, all but two patients achieved osseous union in, on average, 5.6 months. One of these two patients eventually gained union after another surgery with fracture compression along the original nail and concurrent bone grafting. The second patient, undergoing hemodialysis for chronic renal failure, had persistent nonunion. At follow-up, for patients with antegrade nailing, all but four patients had less than 20 degrees limitation of shoulder abduction. For patients with retrograde nailing, all but two had less than 10 degrees limitation of elbow motion. Only the patient with persistent nonunion had continual pain and significant impairment of arm function.

CONCLUSIONS

Humeral locked nailing seems to be effective for humeral delayed unions or nonunions. It may be an acceptable alternative for fractures unsuited for plate fixation, such as those with comminution, osteoporosis, or a severely adhered radial nerve.

A functional model for whole limb transplantation in the rat

To develop a functional model for the study of whole limb transplantation, inbred Lewis rats were used as both donors and recipients. In this model, the recipient biceps femoris muscle was elevated from its distal attachment to preserve part of the adductor function of the limb after surgery. The tibial, peroneal, and sural branches of the sciatic nerve were anastomosed separately to provide faster and more precise functional recovery. For control sensory evaluation, the saphenous branches of the femoral nerve were not reattached. A flat intramedullary pin stabilized with methyl methacrylate was used to rigidly immobilize the femur. The transplanted limbs started bearing weight at 17 to 22 days. Walking on the plantar surface of the hock and adduction of the toes gradually decreased, and the rats developed a normal walking pattern. Sciatic and tibial function indexes, based on walking track analysis, correlated well with clinical observations. In this study, a new model for limb transplantation was developed that provided good and reliable sensory and ambulatory recovery.

In vivo kinematic study of normal wrist motion: an ultrafast computed tomographic study

OBJECTIVE

To quantify in vivo carpal kinematics of a normal wrist in a dynamic continuous model.

DESIGN

The instantaneous changes in the radiocarpal and midcarpal joints during normal wrist motion were analyzed using ultrafast computed tomography (CT).

BACKGROUND

Wrist injuries account for a considerable and growing proportion of work-related disorders and disability. However, little is known about normal wrist kinematics.

METHODS

Ten uninjured subjects were studied using ultrafast CT to measure the continuous motion of the wrist from full flexion to full extension. Sagittal plane scanning was performed mediolaterally at six different locations as the wrists were moved slowly and repeatedly from full flexion to full extension. The data were printed to X-ray film and transferred to an independent work station with a video camera. The motion of the radiocarpal, midcarpal and wrist joints was determined by an image analyzing system.

RESULTS

Wrist motion was expressed as a ratio of capitate-lunate (C-L) (midcarpal) motion and radio-lunate (R-L) (radiocarpal) motion. In the volar flexion of normal wrists, the contribution of the radiocarpal joint and midcarpal joint were approximately equal; while dorsal flexion of the normal wrist occurred mainly at the midcarpal joint.

CONCLUSIONS

In normal wrists, the radiocarpal joint and midcarpal joint contribute equally to volar flexion, while the midcarpal joint is more important in dorsal flexion.

RELEVANCE

In this study, we demonstrated the suitability of using two-dimensional computed tomographic images in a quantitative study of flexion/extension kinematics of the normal wrist.

Reversible, nanometer-scale conductance transitions in an organic complex

Reversible conductance transitions are demonstrated on the molecular scale in a complex of 3-nitrobenzal malononitrile and 1, 4-phenylenediamine, by application of local electric field pulses. Both macroscopic and local current-voltage (I/V) measurements show similar electrical bistability behavior. The mechanism of the electrical bistability is discussed.

GSTM1 and NAT2 polymorphisms in operable and non-operable lung cancer patients

We have genotyped 657 Norwegian men, including 282 lung cancer patients (147 non-operable and 135 operable) and 375 healthy referents (210 smokers and 165 non-smokers), to study the possibility that glutathione S-transferase M1 (GSTM1)-null and/or N-acetyl transferase 2 (NAT2)-slow genotypes confer susceptibility towards lung cancer in smokers. Compared with smoking referents, there was a significant over-representation of the GSTM1-null genotype among patients with squamous cell carcinoma (SQ) [odds ratio (OR) = 1.7, 95% confidence interval (95%CI) = 1.1-2.7], and the NAT2-slow genotype among patients with large cell carcinoma or mixed histological diagnosis (LM) (OR = 2.5, 95%CI = 1.0-6.1). In contrast to operable patients, non-operable patients showed a clear over-representation of slow genotypes if they were younger (</= 63 years; versus older: OR = 3.9, 95%CI = 1.7-8.8) or younger light smokers [</= 30 pack-years (PY); versus heavy smokers: OR = 5.7, 95%CI = 1.4-23.3]. Among younger light smokers, the slow genotype appeared to be associated with an increased risk of developing non-operable tumours only (OR = 6.3, 95%CI = 1.9-20.4), especially other types of tumours than SQ (OR = 10.8, 95%CI = 1.4-83.9). The null genotype (OR = 3.9, 95%CI = 1.1-13.5) and the null/slow combination (OR = 4.5, 95%CI = 1.5-13.8) seemed to increase the risk for non-operable SQ only. These results are supported by logistic regressions of patients allowing interactions between tumour type (or treatment) and PY (or age), and indicate that the GSTM1-null genotype could be an important susceptibility factor for SQ while the NAT2-slow genotype may have an impact on other types of lung cancer. Individuals with the GSTM1-null and/or NAT2-slow genotypes may constitute susceptible groups with increased risk to contract non-operable lung cancer at younger age and lower smoking dose.

Somatic Mutations and Aging : Methods for Molecular Analysis of HPRT Mutations

The increasing information on the specific DNA sequence alterations that occur in mutated genes of human somatic cells has allowed the establishment of mutational spectra. Endogenous and exogenous exposures as well as individual susceptibility factors seem to contribute to the complexity of mutational spectra. The X-linked HPRT (hypoxanthine phosphoribosyl transferase) gene in human T lymphocytes has been considered as a suitable target for studying somatic in vivo mutations (1), including those related to aging. The mutant frequency in adults is 10-fold higher than that in newborns and the proportion of point mutations is also considerably higher in adults (90% vs 20%), possibly as results of accumulation of point mutations induced later in life and dilution of the V(D)J-recombinase-mediated spontaneous deletions observed in newborns (2). A significant age-related increase of HPRT mutant frequency (1-3%/yr) has been reported in most studies, with a more rapid increase in smokers compared to nonsmokers (reviewed in ref. 1).

Validation of the human T-lymphocyte cloning assay--ring test report from the EU concerted action on HPRT mutation (EUCAHM)

The T-cell cloning assay, which enables the enumeration and molecular analysis of 6-thioguanine resistant (HPRT-negative) mutant T-cells, has been extensively used for studying human somatic gene mutation in vivo. However, large inter-laboratory variations in the HPRT mutant frequency (MF) call for further investigation of inter-laboratory differences in the experimental methodology, and development of an optimal but easy uniform cloning protocol. As part of the EU Concerted Action on HPRT Mutation (EUCAHM), we have carried out two Ring tests for the T-cell cloning assay. For each test, duplicate and coded samples from three buffy coats were distributed to five laboratories for determination of MF using six different protocols. The results indicated a good agreement between split samples within each laboratory. However, both the cloning efficiencies (CEs) and MFs measured for the same blood donors showed substantial inter-laboratory variations. Also, different medium compositions used in one and the same laboratory resulted in a remarkable difference in the level of MF. A uniform operating protocol (UOP) was proposed and compared with the traditional protocols in the second Ring test. The UOP (preincubation) increased the CE in laboratories traditionally using preincubation, but decreased the CE in laboratories traditionally using priming. Adjusted for donor, use of different protocols contributed significantly to the overall variation in lnCE (P = 0.0004) and lnMF (P = 0.03), but there was no significant laboratory effect on the lnCE (P = 0.38) or lnMF (P = 0.14) produced by the UOP alone. Finally, a simplified version of the UOP using the serum-free medium X-Vivo 10 and PMA was tested in one laboratory, and found to produce a considerable increase in CE. This modified UOP needs to be further evaluated in order to be used for future databases on HPRT MFs in various populations.

Influence of smoking and donor age on the spectrum of in vivo mutation at the HPRT-locus in T lymphocytes of healthy adults

Types and frequencies of in vivo mutation in the hypoxanthine-guanine phosphoribosyl-transferase (HPRT) gene was studied in 142 T cell mutants from 78 healthy nonsmoking and smoking adults with a mean of 65 years. The HPRT mutant frequency in the nonsmokers was 18.7 +/- 12.0 x 10(-6), and in the smokers 26.6 +/- 18.5 x 10(-6) (mean +/- S.D., P < 0.01). Among 107 single base pair substitutions (SBS) in the coding region of the HPRT gene, one new mutable site, one novel nonsense mutation and three not previously reported SBS were identified. Transitions accounted for 59% of the SBS and transversions for 41%. GC > AT transitions were the predominant type of mutation, with 50% of all SBS. The mutations showed a nonrandom distribution along the coding sequence, with three significant hotspots at positions 143, 197 and 617 (13, 14 and 7 mutations, respectively). There was no difference between smokers and nonsmokers with regard to the distribution of mutations at these hotspot positions. However, 85% of the mutations at GC base pairs and 88% of the mutations at AT base pairs in smokers occurred at sites with guanine or thymine, respectively, in the nontranscribed DNA strand. Moreover, smokers had a higher frequency of transversions and lower frequency of transitions than nonsmokers did. Particularly, GC > TA transversions were increased in smokers (11%) compared to nonsmokers (2%), which suggests that tobacco-smoke induced adducts at guanine bases in the nontranscribed DNA strand contributes to the increase of HPRT mutation in smokers. Overall, these results were very similar to the mutational spectra in two younger study populations reported previously [K.J. Burkhart-Schultz, C.L. Thompson, I.M. Jones, Spectrum of somatic mutation at the hypoxanthine phosphoribosyltransferase (HPRT) gene of healthy people, Carcinogenesis 17 (1996) 1871-1883; A. Podlutsky, A.-M. Osterholm, S.-M. Hou, A. Hofmaier, B. Lambert, Spectrum of point mutations in the coding region of the hypoxanthine-guanine phosphoribosyltransferase, Carcinogenesis 19 (1998) 557-566]. With the possible exception of an increase of mutations at hotspot position 143, and a decrease of 5-methylcytosine deamination mediated transitions at CpG-sites in the older individuals, there were no differences between the mutational spectra of old and young adults. In conclusion, both smoking and ageing seem to have minor influences on the spectrum of HPRT mutation in T cells.

Impact of medical informatics on medical education

In recent years, medical informatics has become a well-recognized branch of medicine. It is a multidisciplinary science that combines information technology and various specialties of medicine. The impact of medical informatics on medical education is advancing along with the rapid developments in computer science. Departments of medical informatics or similar divisions have appeared in schools of medicine in Taiwan in the past 5 years. At National Taiwan University College of Medicine, we offer curricula in basic computer concepts, network concepts, operating systems, word processing, database and data processing, computer media resources, multimedia computer statistics, intelligent health information systems, medical diagnostic support systems, and electronic medical record systems. Distance learning has also been favorably accepted on this campus. Recently, we proposed the concept of a virtual medical campus, which will break the physical barriers of time and space. We expect this revolution to influence every aspect of medicine, especially medical education.

Recent advances in telemedicine

With continuing advances in information technology, the applications of computers in medicine are increasing rapidly. Modern information technology not only affects the delivery of health care, but also significantly influences the doctor-patient relationship. Since the 1990s, technologic developments in high-bandwidth telecommunications systems and digitizing devices have led to a surge of interest in telemedicine. In recent years, the Internet, with its powerful penetration and scalability, has become an increasingly popular medical information resource and a new platform for telemedicine. The impact of modern technology on the advancement of telemedicine in Taiwan started with the 1995 National Information Infrastructure project, which uses networks of different bandwidths for teleconsultation and distance education programs. In 1998, National Taiwan University and Taipei Medical College in Taiwan, and the University of Pittsburgh and the University of Iowa in the USA, began cooperation on a new Cyber Medical Center (CMC) project that integrates the technologies of multimedia, database management, a multiple-site videoconferencing system, and the World Wide Web. The aim of the CMC is to create a multimedia network system for the management of electronic patient records, teleconsultation, online continuing medical education, and information services on the Web. In the future, telemedicine systems in Taiwan are expected to combine the Internet and cable television to connect clinics, hospitals, insurance organizations, and public health administrations; and, finally, to extend health services to every household.

Anatomic considerations of locked humeral nailing

To investigate the risk of axillary nerve injury by the proximal locking screws in antegrade nailing of humeral fractures, the anatomy of the axillary nerve was examined in 20 fresh anatomic specimen humeri, which subsequently were nailed antegrade with specially designed humeral locked nails. The axillary nerve was found to be on average 45.6 mm below the tip of the greater tuberosity; it was jeopardized by insertion of the lower proximal locking screw in one of the 20 specimens. Short humeri, humeri with small heads, or too deeply inserted nails may increase the risk of nerve injury; likewise, a lower location and more horizontal direction of the locking screws and a greater curvature of the nail can heighten the risk. In addition to the examination of the axillary nerve, a geometric study of these anatomic specimen was performed and was aimed at improving retrograde nailing technique and thus treatment results. The humeral geometry indicated that for the best linearity in the sagittal plane, an entry portal incorporating the superior margin of the olecranon fossa would be recommended for the 14 humeri with a distal humeral offset less than 4 mm, whereas a supracondylar entry portal would be recommended for the six humeri with an offset larger than 4 mm. For best linearity in the coronal plane, the entry portal and nailing direction should be more lateral in humeri with a smaller humeral elbow angle.

Influence of genetic polymorphisms of biotransformation enzymes on gene mutations, strand breaks of deoxyribonucleic acid, and micronuclei in mononuclear blood cells and urinary 8-hydroxydeoxyguanosine in potroom workers exposed to polyaromatic hydrocarbons

OBJECTIVES

Airborne exposure to polycyclic aromatic hydrocarbons (PAH) in the potroom of an aluminum reduction plant was studied in relation to genotoxic or mutagenic effects, and the possibility of host genotypes of different metabolizing enzymes modifying associations between PAH exposure and genotoxic or mutagenic response was assessed.

SUBJECTS AND METHODS

Ninety-eight male potroom workers and 55 male unexposed blue-collar workers constituted the study population. Micronuclei in CD4+ and CD8+ lymphocytes, DNA (deoxyribonucleic acid) single-strand breaks, hypoxanthine guanine phosphoribosyl transferase (HPRT) mutation frequency, and genotype for cytochrome P-4501A1, glutathione transferases M1, T1 and P1, and microsomal epoxide hydrolase were analyzed using peripheral mononuclear cells. Urine samples were collected for the analysis of 8-hydroxydeoxyguanosine.

RESULTS

Micronuclei in peripheral CD4+ and CD8+ lymphocytes, DNA single-strand breaks, HPRT mutation frequency, and 8-hydroxydeoxyguanosine in urine did not differ between the potroom workers and the unexposed referents. With the exception of an observed exposure-response relationship for potroom workers with Tyr/Tyr genotype for microsomal epoxide hydrolase, between airborne PAH and CD8+ micronuclei, no correlations were found between any of the genotoxicity biomarkers and any of the exposure measures (airborne particulate PAH, airborne gas phase PAH, length of employment in the potroom, 1-hydroxypyrene in urine, or PAH-DNA adducts in peripheral lymphocytes), also when genotypes for biotransforamtion enzymes were considered.

CONCLUSIONS

The results indicate that the employed biomarkers of mutagenic or genotoxic effects are not appropriate for surveillance studies of potroom workers exposed to current airborne levels of PAH. The significance of the correlation between airborne PAH and CD8+ micronuclei in Tyr/Tyr genotype subjects should be evaluated.

Antegrade locked nailing for humeral shaft fractures

Treatment results of antegrade locked nailing of acute humeral shaft fractures, including union rate and recovery of shoulder function, have been inconsistent. This led the current authors to hypothesize that implant design and surgical techniques might account for this inconsistency. In the current study, 47 fractures (38 acute; nine pathologic) in 47 patients achieved union with the techniques of closed nailing, short to long segment nailing, and fracture compression. Satisfactory recovery of shoulder function occurred because of minimal surgical trauma, prevention of impingement by the nail or locking screws, and prevention of axillary nerve injury or comminution of the humeral head. Forty-seven patients with 38 acute fractures and nine pathologic fractures were treated with humeral locked nails. Mean followup time was 21.4 months. With a single operation, all 38 acute fractures proceeded to eventual union; the average time to union was 7.8 weeks. Thirty-five patients had excellent or satisfactory recovery of shoulder function. Complications included slipout of the proximal screw, nail breakage, fragment displacement, and transient postoperative radial nerve palsy. All nine patients with pathologic fractures had substantial pain relief and increased arm function after surgery. The current study shows the reliability of antegrade locked nailing for proximal and middle third fractures of the humeral shaft.

Antioxidant status following acute ischemic limb injury: a rabbit model

Although ischemic injury to skeletal muscle is a matter of great clinical importance, relatively little is known about the mechanisms which determine systemic responses. One purpose of this study is to elucidate the systemic antioxidant status following an episode of acute ischemic limb injury and subsequent reperfusion. Twelve New Zealand white rabbits were used in this study. After the animals were anesthetized, an ischemic insult was created in the right hind limb for twelve hours, followed by four hours of reperfusion. Several series of blood samples were obtained. At the end of the experiment, the animals were killed and necropsies undertaken in order to evaluate the antioxidant status of various visceral organs. The results link ischemia and reperfusion injury to a significant decline in antioxidative activity in various tissues. The weakening in antioxidant status after ischemic limb injury was most pronounced in the heart tissue, followed in descending order by the spleen, skeletal muscle, lung, liver, and kidney tissue. The levels of specific antioxidants and reactive oxygen species in various organs changed significantly, and the changes were tissue specific. Endogenous radical scavenging systems were not entirely overwhelmed in most of the tissues studied. But higher levels of malondialdehyde (MDA) found in cardiac tissue suggest that the production of oxygen free radicals is accelerated by an ischemic injury. Based on the study, we believe that the cardiac tissue is particularly susceptible to the effects of ischemia and reperfusion injury. Damage to cardiac tissue is probably the major cause of mortality following acute ischemic injury in a limb.

Early diagnosis of single segment vertebral osteomyelitis--MR pattern and its characteristics

Nine cases of single segment vertebral osteomyelitis were included based on the single level of vertebral body involvement according to the MR findings. They were 3 cases with tuberculous infection and 6 cases with pyogenic infection. The vertebral body involvement was presented as abnormal signal changes (100%) and heterogenous enhancement (77.7%). They usually caused the cortical disruption in its anterior aspect (100%). It goes along the upward subligamentous spread (100%) most often, then the upper disc involvement (66.6%) and downward subligamentous spread (55.5%). The lower disc involvement is least common (11.1%). By using these criteria, the single segment vertebral osteomyelitis could be earlier diagnosed.

Hprt mutant frequency and aromatic DNA adduct level in non-smoking and smoking lung cancer patients and population controls

T cell cloning and 32P-post-labelling methods were used to study the mutant frequency (MF) at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus and the aromatic DNA adduct level (AL) in peripheral lymphocytes of newly diagnosed lung cancer patients (92 ever-smokers and 87 never-smokers) and matched population controls (82 ever-smokers and 79 never-smokers). Overall, the MF (total mean 20.6 x 10(-6)) and AL (4.1 x 10(-8)) were similar in cases and controls with the same smoking status, indicating that the disease has limited effect on the two endpoints. When cases and controls were combined, the AL was significantly higher in current smokers than in former or never-smokers (P = 0.0003) and the MF was significantly higher in ever-smokers than in never-smokers (P = 0.004). Age affected the MF significantly in ever-smokers (1.6%/year, 95% CI 0.6-2.5, adjusted for pack-years and years since last smoking), especially among cases (2.1%/year, 95% CI 0.5-3.7). An increase of AL with age was observed in currently smoking cases only (2.3%/year, 95% CI 0.3-4.2, adjusted for smoking dose). For currently smoking cases, there was also a more pronounced effect of smoking dose on both endpoints and a significant correlation between AL and MF (r = 0.52, P = 0.04) was observed among those with the highest dose. Our data also provide additional evidence for the different turnover times of smoking-induced DNA adducts and hprt mutations. The stronger increase of MF and AL with age and dose in currently smoking patients compared with controls is consistent with an interaction between smoking and genetic host factors.

Locked nailing for displaced surgical neck fractures of the humerus

OBJECTIVE

To report experience with a newly devised humeral locked nail for treating surgical neck fractures of the humerus. This device has the advantages of a small diameter for minimal tissue trauma and transfixing locking screws for reliable fixation.

METHODS

From 1993 to 1996, 21 consecutive severely displaced surgical neck fractures of the humerus were antegrade nailed with humeral locked nails; 2 fractures were associated with dislocation and 1 fracture was a comminuted metaphyseal fracture with a failed plating. The average age of patients was 65.8 years; average follow-up time was 19.2 months. The proximal screws were applied upward in 5 patients and downward in 16 patients. Static locking was performed in 8 patients, dynamic locking in 13 others.

RESULTS

The average operation time was 55 minutes. No patients needed blood transfusion. All fractures eventually achieved union with an average time to union of 14.8 weeks. On the basis of Neer criteria for outcome analysis, excellent or satisfactory results were obtained for 86% of the patients (18 of 21 patients). No patients had deep infection, implant failure, malunion, osteonecrosis, or nail migration that interfered with joint motion. Due to technique errors, one patient had shoulder joint impingement caused by protrusion of the proximal nail tip.

CONCLUSION

The operative method reported here has the advantages of minimal tissue trauma, minimal hardware application, sufficient fixation, and easy operative technique, and it can be a worthy alternative for the treatment of severely displaced surgical neck fractures of the humerus.

Glutathione S-transferase mu1 and N-acetyltransferase 2 genetic polymorphisms and exposure to tobacco smoke in nonsmoking and smoking lung cancer patients and population controls

We conducted a case-control study to assess the risk of lung cancer in relation to genetic polymorphisms of the detoxifying enzymes glutathione-S-transferase mu1 (GSTM1) and N-acetyl transferase 2 (NAT2), focusing on never-smokers, women, and older people. The study base consisted of persons > or =30 years of age in Stockholm County from 1992 to 1995. We recruited never-smoking lung cancer cases and a sex- and age-matched sample of ever-smoking cases at the three county hospitals mainly responsible for diagnosing and treating lung cancer. A total of 185 cases (25.4% men; 47.6% never-smokers) and 164 frequency-matched population controls (28.7% men; 48.2% never-smokers) supplied blood for genotyping. Detailed information was collected by interview on active and passive smoking, occupations, residences, and diet. The overall odds ratio (OR) for lung cancer associated with the GSTM1 null (GSTM1-) versus GSTM1+ genotype was 0.8 [95% confidence interval (CI), 0.5-1.2], with an OR close to unity among smokers, and lower ORs suggested among never-smokers. For NAT2 slow versus rapid acetylator genotypes, the OR was 1.0 (95% CI, 0.6-1.5) overall, which broke down into an increased risk for slow acetylators among never-smokers but an increased risk for rapid acetylators among smokers. Among never-smokers, a gene interaction was suggested, with combined slow acetylator and GSTM1+ genotype conferring particularly high risk (OR = 3.1; 95% CI, 1.1-8.6), but no clear pattern emerged among smokers. A detailed analysis among smokers showed no interaction between pack-years of smoking and the GSTM1 genotype but suggested a steeper increase in risk with increasing pack-years of smoking exposure for rapid than for slow acetylators. Our results do not support a major role for the GSTM1 genetic polymorphism as a risk factor for lung cancer among smokers or nonsmokers. There was, however, some suggestion that the slow acetylator genotype may confer an increased risk among never-smokers and that the rapid acetylator genotype interacts with pack-year dose to produce a steeper risk gradient among smokers.

Molecular characterization of two deletion events involving Alu-sequences, one novel base substitution and two tentative hotspot mutations in the hypoxanthine phosphoribosyltransferase (HPRT) gene in five patients with Lesch-Nyhan syndrome

Mutations identified in the hypoxanthine phosphoribosyltransferase (HPRT) gene of patients with Lesch-Nyhan (LN) syndrome are dominated by simple base substitutions. Few hotspot positions have been identified, and only three large genomic rearrangements have been characterized at the molecular level. We have identified one novel mutation, two tentative hot spot mutations, and two deletions by direct sequencing of HPRT cDNA or genomic DNA from fibroblasts or T-lymphocytes from LN patients in five unrelated families. One is a missense mutation caused by a 610C-->T transition of the first base of HPRT exon 9. This mutation has not been described previously in an LN patient. A nonsense mutation caused by a 508C-->T transition at a CpG site in HPRT exon 7 in the second patient and his younger brother is the fifth mutation of this kind among LN patients. Another tentative hotspot mutation in the third patient, a frame shift caused by a G nucleotide insertion in a monotonous repeat of six Gs in HPRT exon 3, has been reported previously in three other LN patients. The fourth patient had a tandem deletion: a 57-bp deletion in an internally repeated Alu-sequence of intron 1 was separated by 14 bp from a 627-bp deletion that included HPRT exon 2 and was flanked by a 4-bp repeat. This complex mutation is probably caused by a combination of homologous recombination and replication slippage. Another large genomic deletion of 2969 bp in the fifth patient extended from one Alu-sequence in the promoter region to another Alu-sequence of intron 1, deleting the whole of HPRT exon 1. The breakpoints were located within two 39-bp homologous sequences, one of which overlapped with a well-conserved 26-bp Alu-core sequence previously suggested as promoting recombination. These results contribute to the establishment of a molecular spectrum of LN mutations, support previous data indicating possible mutational hotspots, and provide evidence for the involvement of Alu-mediated recombination in HPRT deletion mutagenesis.

Biomechanical comparison of antegrade and retrograde nailing of humeral shaft fracture

A pair-controlled study was conducted to compare biomechanical properties of antegrade and retrograde nailing of humeral fractures. First, six paired fresh anatomic specimen humeri were used to compare the properties of humeri fractured at the middle to distal diaphyses junction that were nailed from the retrograde approach with the Humeral Locked nail with those of contralateral intact humeri. An 18 additional pairs were divided into three equal groups by distal, proximal, or mid-diaphysis location of a standardized 5-mm bone defect to simulate unstable fractures. The retrograde and antegrade nailings were performed in each pair in a random manner. Nail and bone constructs were tested for bending stiffness by nondestructive three-point bending and for torsional stiffness by destructive torsional tests. Compared with intact humeri, fractured humeri fixed with nails had 28.6% posteroanterior and 31.4% mediolateral bending stiffness, 22.5% torsional stiffness, and 43.3% failure torque. For distal fractures, retrograde nailing showed significantly more initial stability and higher bending and torsional stiffness; for proximal fractures, antegrade nailing showed similar properties. For middle to distal diaphyses junction fractures, retrograde and antegrade nailing were indistinguishable. The defect created as an entry portal for retrograde nailing reduced the bone strength only 11.1%. These results suggest that retrograde nailing, which is less detrimental to shoulder function than is antegrade nailing, is an acceptable alternative treatment for humeral shaft fractures. In addition, nailing from the short to the long bone segments can improve mechanical properties of the fixation construct because of better nail and bone interface purchase.