Association between the mental domain of the comprehensive geriatric assessment and prolonged length of stay in hospitalized older adults with mild to moderate frailty

Introduction

Previous researches have shown the risk factors of prolonged length of stay (PLOS) in hospitalized older adults, but it is unclear what are the risk factors of PLOS in hospitalized older adults with mild to moderate frailty.

Objective

To identify the risk factors of PLOS in hospitalized older adults with mild to moderate frailty.

Methods

We recruited adults aged ≥65 years old with mild to moderate frailty admitted to a tertiary medical center in the southern Taiwan from June 2018 to September 2018. Each individual underwent a structural questionnaire interview within 72 h after admission and 72 h after discharge. The data were collected face-to-face, including demographic characteristics, comorbidities, length of stay (LOS), and multiple domains of the comprehensive geriatric assessment. The main outcome was PLOS.

Results

Individuals who had two or more drugs, were female, did not have cognitive impairment and had a Geriatric Depression Scale score ≥ 1 had a higher risk of PLOS (probability = 0.81), and these individuals accounted for 29% of the overall study population. Among male individuals younger than 87 years old, those with cognitive impairment had a higher risk of PLOS (probability = 0.76), and among male individuals without cognitive impairment, living alone was associated with a higher risk of PLOS (probability = 0.88).

Conclusion

Early detection and management of mood and cognition in older adults, together with comprehensive discharge planning and transition care, may be an important part of reducing LOS in hospitalized older adults with mild to moderate frailty.

Characterization of host and escherichia coli strains causing recurrent urinary tract infections based on molecular typing

BACKGROUND

Escherichia coli is the leading pathogen responsible for urinary tract infection (UTI) and recurrent UTI (RUTI). Few studies have dealt with the characterization of host and bacteria in RUTI caused by E. coli with genetically identical or different strains. This study aimed to investigate the host and bacterial characteristics of E. coli RUTI based on molecular typing.

RESULTS

Patients aged 20 years or above who presented with symptoms of UTI in emergency department or outpatient clinics between August 2009 and December 2010 were enrolled. RUTI was defined as patients had 2 or more infections in 6 months or 3 or more in 12 months during the study period. Host factors (including age, gender, anatomical/functional defect, and immune dysfunction) and bacterial factors (including phylogenicity, virulence genes, and antimicrobial resistance) were included for analysis. There were 41 patients (41%) with 91 episodes of E. coli RUTI with highly related PFGE (HRPFGE) pattern (pattern similarity > 85%) and 58 (59%) patients with 137 episodes of E. coli RUTI with different molecular typing (DMT) pattern, respectively. There was a higher prevalence of phylogenetic group B2 and neuA and usp genes in HRPFGE group if the first episode of RUTI caused by HRPFGE E. coli strains and all episodes of RUTI caused by DMT E. coli strains were included for comparison. The uropathogenic E. coli (UPEC) strains in RUTI were more virulent in female gender, age < 20 years, neither anatomical/ functional defect nor immune dysfunction, and phylogenetic group B2. There were correlations among prior antibiotic therapy within 3 months and subsequent antimicrobial resistance in HRPFGE E. coli RUTI. The use of fluoroquinolones was more likely associated with subsequent antimicrobial resistance in most types of antibiotics.

CONCLUSIONS

This study demonstrated that the uropathogens in RUTI were more virulent in genetically highly-related E. coli strains. Higher bacterial virulence in young age group (< 20 years) and patients with neither anatomical/functional defect nor immune dysfunction suggests that virulent UPEC strains are needed for the development of RUTI in healthy populations. Prior antibiotic therapy, especially the fluoroquinolones, within 3 months could induce subsequent antimicrobial resistance in genetically highly-related E. coli RUTI.

Machine learning to predict the development of recurrent urinary tract infection related to single uropathogen, Escherichia coli

Recurrent urinary tract infection (RUTI) can damage renal function and has impact on healthcare costs and patients' quality of life. There were 2 stages for development of prediction models for RUTI. The first stage was a scenario in the clinical visit. The second stage was a scenario after hospitalization for urinary tract infection caused by Escherichia coli. Three machine learning models, logistic regression (LR), decision tree (DT), and random forest (RF) were built for the RUTI prediction. The RF model had higher prediction accuracy than LR and DT (0.700, 0.604, and 0.654 in stage 1, respectively; 0.709, 0.604, and 0.635 in stage 2, respectively). The decision rules constructed by the DT model could provide high classification accuracy (up to 0.92 in stage 1 and 0.94 in stage 2) in certain subgroup patients in different scenarios. In conclusion, this study provided validated machine learning models and RF could provide a better accuracy in predicting the development of single uropathogen (E. coli) RUTI. Both host and bacterial characteristics made important contribution to the development of RUTI in the prediction models in the 2 clinical scenarios, respectively. Based on the results, physicians could take action to prevent the development of RUTI.

Clinical Frailty Scale in Predicting Postoperative Outcomes in Older Patients Undergoing Curative Surgery for Urologic Malignancies: A Prospective Observational Cohort Study

OBJECTIVE

To examine the utility of the Clinical Frailty Scale (CFS) in predicting outcomes in older adults with urologic malignancies undergoing curative surgeries.

METHODS

This prospective observational cohort study was conducted in a university-based tertiary medical center. Patients aged 75 years or older who were scheduled to undergo curative surgery for a urologic malignancy from January 2017 to December 2017 were recruited. Patients were grouped according to the CFS scores. The primary postoperative outcome measures were a major complication within 30 days and a decline in the activities of daily living (ADL) within 30 days and 90 days. Multivariable analyses and the area under the receiver operating characteristic curve were performed to investigate the association between the CFS and postoperative outcomes.

RESULTS

A total of 82 patients, 50% women, were enrolled with mean age 81.6 years. The CFS was significantly associated with postoperative outcomes in a dose-response relationship. When compared with those with a CFS <5, patients with CFS scores ≥5 had a 10.3-times higher risk for a major complication, 8.5-times and 21.4-times higher risk for a decline in ADL within 30 days and 90 days. The area under the receiver operating characteristic curves for the CFS to predict a major complication, the 30-day decline in ADL and the 90-day decline in ADL were 0.60, 0.73, and 0.79.

CONCLUSION

A higher CFS score predicted a higher risk of poor outcomes in this population. It is recommended that patients with higher CFS scores, especially above 5, are needed to receive further multidisciplinary perioperative care.

Associations Between Geriatric Syndromes and Mortality in Community-Dwelling Elderly: Results of a National Longitudinal Study in Taiwan

OBJECTIVE

Although geriatric syndromes have been studied extensively, their interactions with one another and their accumulated effects on life expectancy are less frequently discussed. This study examined whether geriatric syndromes and their cumulative effects are associated with risks of mortality in community-dwelling older adults.

METHODS

Data were collected from the Taiwan Longitudinal Study in Aging in 2003, and the participant survival status was followed until December 31, 2007. A total of 2744 participants aged ≥65 years were included in this retrospective cohort study; 634 died during follow-up. Demographic factors, comorbidities, health behaviors, and geriatric syndromes, including underweight, falls, functional impairment, depressive condition, and cognitive impairment, were assessed. Cox proportional hazard regression analysis was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the probability of survival according to the cumulative number of geriatric syndromes.

RESULTS

The prevalence of geriatric syndromes increased with age. Mortality was significantly associated with age ≥75 years; male sex; ≤6 years of education; history of stroke, malignancy; smoking; not drinking alcohol; and not exercising regularly. Geriatric syndromes, such as underweight, functional disability, and depressive condition, contributed to the risk of mortality. The accumulative model of geriatric syndromes also predicted higher risks of mortality (N = 1, HR 1.50, 95% CI 1.19-1.89; N = 2, HR 1.69, 95% CI 1.25-2.29; N ≥ 3, HR 2.43, 95% CI 1.62-3.66).

CONCLUSIONS

Community-dwelling older adults who were male, illiterate, receiving institutional care, underweight, experiencing a depressive condition, functionally impaired, and engaging in poor health behavior were more likely to have a higher risk of mortality. The identification of geriatric syndromes might help to improve comprehensive care for community-dwelling older adults.

Compliance Index, a Marker of Peripheral Arterial Stiffness, may Predict Renal Function Decline in Patients with Chronic Kidney Disease

BACKGROUND

Compliance index derived from digital volume pulse (CI-DVP), measuring the relationship between volume and pressure changes in fingertip, is a surrogate marker of peripheral arterial stiffness. This study investigated if CI-DVP can predict renal function deterioration, cardiovascular events and mortality in patients with chronic kidney disease (CKD).

METHODS

In this prospective observational study, 149 CKD patients were included for final analysis. CI-DVP and brachial-ankle pulse wave velocity (baPWV) were measured, decline in renal function was assessed by the estimated glomerular filtration rate (eGFR) slope. Composite renal and cardiovascular outcomes were evaluated, including ≥50% eGFR decline, start of renal replacement therapy, and major adverse events.

RESULTS

Patients in CKD stages 3b to 5 had higher baPWV and lower CI-DVP values than those in patients with CKD stages 1 to 3a. Stepwise multivariate linear regression analysis showed that lower CI-DVP (p =0.0001) and greater proteinuria (p =0.0023) were independent determinants of higher eGFR decline rate. Multivariate Cox regression analysis revealed that CI-DVP (HR 0.68, 95% CI 0.46-1.00), baseline eGFR (HR 0.96, 95% CI 0.94-0.98) and serum albumin (HR 0.17, 95% CI 0.07-0.42) were independent predictors for composite renal and cardiovascular outcomes.

CONCLUSIONS

Compliance index, CI-DVP, was significantly associated with renal function decline in patients with CKD. A higher CI-DVP may have independent prognostic value in slower renal function decline and better composite renal and cardiovascular outcomes in CKD patients.

Incidence of end stage renal disease among type 1 diabetes: a nationwide cohort study in Taiwan

The aim of our study was to estimate the risk of end-stage renal disease (ESRD) in type 1 diabetes mellitus (T1DM) in Taiwanese people; in addition, our goal was to determine how the age, year, and sex at registration of T1DM affects the risk. Population-based cohort study. A nationwide cohort study of 7203 Taiwanese patients with T1DM registered in 1999 to 2010 was followed up until ESRD, death, or the end of follow-up on December 31, 2010. Annual age-, sex-, and calendar year-specific incidence rates of ESRD of the general population were used to calculate the standardized incidence ratio (SIR) of ESRD in relation to T1DM. The SIR of ESRD for male and female patients with T1DM was significantly increased at 25.85 (95% CI 23.40-28.29) and 28.08 (95% 25.45-30.71), respectively; the peak was at age 15 to 29 years for both genders. The cumulative incidence of ESRD was similar in male and female patients but was significantly higher in patients≥ 30 years old than in patients<30 years old (10.25% vs. 3.57%, P<0.001). Patients aged <15 years had a significantly lower risk of ESRD as compared to those aged 15 to 29 years; patients aged 30 to 44 (adjusted HR, 1.491) and 45 to 60 years (adjusted HR, 2.111) showed significantly increased hazards. Our data also demonstrated a lower risk of ESRD in patients who were registered in later years than in earlier years. The risk of ESRD is substantially increased in T1DM in the ethnic Chinese population. The continuously declining risk of ESRD in T1DM may advocate the use of a multidisciplinary chronic kidney disease care system in Taiwan.

Clinical and microbiological characteristics of Klebsiella pneumoniae from community-acquired recurrent urinary tract infections

Understanding the pathogenesis of recurrent urinary tract infection (RUTI) and whether it is attributable to reinfection with a new strain or relapse with the primary infecting strain is of considerable importance. Because previous studies regarding community-acquired Klebsiella pneumoniae RUTI are inconclusive, we undertook this study to evaluate the characteristics of the host and the bacterial agent K. pneumoniae in RUTI. A prospective study was designed, using consecutive patients diagnosed with community-acquired K. pneumoniae-related UTI from January 2007 to December 2009. Of the total 468 consecutive episodes, we found 7 patients with RUTI. All the patients with RUTI were elderly (median, 74 years), with diabetes (100 %, 7 out of 7). Clinical K. pneumoniae isolates derived from the same patients with RUTI revealed identical genomic fingerprints, indicating that K. pneumoniae UTI relapsed despite appropriate antibiotic therapy. The antimicrobial resistance, growth curve and biofilm formation of the recurrent isolates did not change. K. pneumoniae strains causing RUTI had more adhesion and invasiveness than the colonization strains (p < 0.01). When we compared the recurrent strains with the community-acquired UTI strains, the prevalence of diabetes mellitus was significant (100 % vs 53.7 %, p = 0.03) in the RUTI group. Our data suggest that K. pneumoniae strains might be able to persist within the urinary tract despite appropriate antibiotic treatment, and the greater adhesion and invasiveness in the recurrent strains may play an important role in recurrent infections.

Clinical and microbiological characteristics of peritoneal dialysis-related peritonitis caused by Klebsiella pneumoniae in southern Taiwan

BACKGROUND/PURPOSE(S)

Gram-negative peritonitis is a frequent and serious complication of peritoneal dialysis (PD). No previous reports have focused on Klebsiella pneumoniae infection. The aim of this study was to investigate the host and bacterial factors associated with K. pneumoniae PD-related peritonitis.

METHODS

We retrospectively studied K. pneumoniae PD-peritonitis cases treated at a university hospital in southern Taiwan during 1990-2011, and analyzed the clinical features and outcomes and bacterial characteristics of serotypes, hypermucoviscosity (HV), and virulence-associated genes such as wabG, uge, and rmpA in K. pneumoniae PD-related peritonitis. Fifty-four isolates of K. pneumoniae-related community-acquired urinary tract infection (UTI) and 76 morphologically different nonpathogenic K. pneumoniae isolates from healthy adults were used as controls.

RESULTS

K. pneumoniae was the second most common monomicrobial pathogen causing Gram-negative PD-related peritonitis (n = 13, 2.7%), and the most common pathogen involved in polymicrobial peritonitis (16/43, 37.2%) and associated with high catheter removal rate (7/16, 43.8%). Compared with Escherichia coli peritonitis cases, patients with monomicrobial K. pneumoniae peritonitis also had insignificantly higher incidence of sepsis/bacteremia [n = 5 (38%), p = 0.11] and a higher mortality rate [n = 3 (23%), p = 0.36]. The prevalence of K1/K2 (n = 1, 7.7%) serotypes was low, but there was a higher prevalence of serotype K20 (n = 3, 23.1%) in K. pneumoniae isolates derived from monomicrobial PD-related peritonitis compared with control groups. HV phenotype (p < 0.001) and rmpA genotype (p = 0.007) were absent in the peritonitis group.

CONCLUSION

This is the first study focused on clinical and microbiological characteristics of K. pneumoniae PD-related peritonitis. K. pneumoniae was a common Gram-negative pathogen causing monomicrobial and polymicrobial PD-related peritonitis in southern Taiwan. The bacterial characteristics with low percentage of capsular serotype K1/K2, no significant HV, and absence of rmpA suggest a different pathogenesis in K. pneumoniae PD-related peritonitis compared with that in UTI and liver abscess.

Innovations in drug-eluting stents

Coronary artery disease affects patients worldwide and is a major cause of morbidity and mortality. Historically, the treatment approach for patients with coronary syndromes has been surgical. In the 1970s, percutaneous balloon angioplasty was introduced, leading to creation of a new field of interventional cardiology, which allowed a non-surgical minimally invasive approach to treat patients with coronary artery disease. However, the major limitations of balloon angioplasty were acute vessel closure and later restenosis. The introduction of bare metal stents and then drug-eluting stents (DES) revolutionized the practice of interventional cardiology and allowed for safe treatment of increasingly complex coronary artery lesions. Although drug-eluting coronary stents improve patient outcomes, they still have limitations. These limitations may arise from delayed endothelialization, local vessel hypersensitivity and endothelial dysfunction secondary to the drug elution, the durable polymer coating, or the stent scaffold. This comprehensive review will discuss the evolution of intracoronary stents from their introduction to current utilization of DES as well as future research on bioabsorbable stents and polymers.

Incidence of progression from newly diagnosed systemic lupus erythematosus to end stage renal disease and all-cause mortality: a nationwide cohort study in Taiwan

AIM

End-stage renal disease (ESRD) is a common finding in systemic lupus erythematosus (SLE) and may contribute to mortality. The purpose of the study was to investigate the incidence of ESRD and all-cause mortality and their risk factors in patients newly diagnosed with SLE in Taiwan.

METHODS

This nationwide cohort study used data from the National Health Insurance Research Database. We identified 4130 newly diagnosed SLE patients at risk for ESRD during 2000-2002; among them, 103 developed ESRD by the end of 2008. Additional 412 age- and sex-matched incident ESRD non-SLE patients served as controls for the survival analysis.

RESULTS

Of the newly diagnosed SLE patients, 2.5% developed ESRD. Age (adjusted hazards ratio [HR] 0.66 for each 1-year increase; 95% confidence interval [CI] 0.47-0.94) and male gender (adjusted HR 2.24; 95% CI 1.4-3.6) were significantly associated with ESRD development. Survival analysis conducted after ESRD development revealed a higher mortality risk among the older patients (HR 1.04; 95% CI 1.02-1.05). Survival analysis in the younger population (age < 40 years) after ESRD development revealed a significant mortality risk among SLE patients (HR 2.73; 95% CI 1.22-6.07).

CONCLUSION

In the follow-up of newly diagnosed SLE patients in Taiwan, younger age and male gender were risk factors for ESRD development. After entering ESRD, these risk factors had different impacts on mortality. Despite the overall improvement in care of patients with lupus nephritis, survival is still poorer in the younger age population.

Estimation of expected life-years saved from successful prevention of end-stage renal disease in elderly patients with diabetes: a nationwide study from Taiwan

OBJECTIVE

Because of the increasing incidence and prevalence of diabetes as a leading cause of end-stage renal disease (ESRD) in the aging population, we estimated the expected life-years (LYs) saved from successful prevention of ESRD in elderly patients with diabetes.

RESEARCH DESIGN AND METHODS

We conducted a population-based cohort study using the National Health Insurance Research Database. We identified all incidences of ESRD in the individuals >65 years of age who were receiving maintenance hemodialysis (N = 24,243) from the registry files of catastrophic illnesses in Taiwan from 1 July 1997 to 31 December 2005. We then retrospectively searched the database to determine whether there had been a diagnosis of diabetes in these cases. After the exclusion of individuals with malignancy (n = 3,423), we extrapolated the survival rates through the end of 2006 using the Monte Carlo method. Using the data of preventable ESRD cases due to diabetes and expected years of life lost (EYLL) in each age stratum, we further estimated the expected LYs saved from successful prevention of ESRD in elderly patients with diabetes.

RESULTS

The estimated average EYLL was 10.6-5.8 and 12.3-7.3 years for diabetic males and females, respectively, aged 65-79 years. In total, 5,430.1 LYs and 10,177 LYs could be saved by the successful prevention of ESRD in male and female elderly patients with diabetes, respectively, in a single year.

CONCLUSIONS

The LYs saved by successful prevention of ESRD in elderly patients with diabetes in a single year are substantial and deserve special attention, especially in elderly females.

BNips: a group of pro-apoptotic proteins in the Bcl-2 family

BNip (formerly known as Nip) proteins, including homologues isolated from human, mouse and Caenorhabditis. elegans, are a relatively new subgroup of the Bcl-2 family. These proteins are classified into this family based on limited sequence homology with the Bcl-2 homology domain 3 and carboxyl terminal transmembrane domain. BNip proteins were first discovered based on their interaction with the adenovirus E1B 19 kDa/Bcl-2 family protein and since then, their roles in cell death pathways have been actively studied. However, the precise mechanisms by which the BNip proteins induce apoptosis and/or necrosis remain to be determined. To advance our knowledge, we have provided a summary and review of current literature regarding BNip proteins including comparative sequence analysis, mutational mapping of the functional domains, and cell death mechanisms involving disruption of mitochondrial homeostasis. Since BNip proteins are expressed at high levels in the heart as compared to other organs, their roles in cardiomyocyte injury during hypoxia or viral infection is a focus of this review. Finally, we discuss potential directions for further study on this increasingly important group of pro-apoptotic proteins.

Production of herbicide-resistant transgenic Panax ginseng through the introduction of the phosphinothricin acetyl transferase gene and successful soil transfer

Herbicide-resistant transgenic Panax ginseng plants were produced by introducing the phosphinothricin acetyl transferase (PAT) gene that confers resistance to the herbicide Basta (bialaphos) through Agrobacterium tumefaciens co-cultivation. Embryogenic callus gathered from cotyledon explants of P. ginseng were pre-treated with 0.5 M sucrose or 0.05 M MgSO(4 )before Agrobacterium infection. This pre-treatment process markedly enhanced the transient expression of the beta-glucuronidase (GUS) gene. Embryogenic callus was initially cultured on MS medium supplemented with 400 mg/l cefotaxime for 3 weeks and subsequently subcultured five times to a medium containing 25 mg/l kanamycin and 300 mg/l cefotaxime. Somatic embryos formed on the surfaces of kanamycin-resistant callus. Upon development into the cotyledonary stage, these somatic embryos were transferred to a medium containing 50 mg/l kanamycin and 5 mg/l gibberellic acid to induce germination and strong selection. Integration of the transgene into the plants was confirmed by polymerase chain reaction and Southern analyses. Transfer of the transgenic ginseng plantlets to soil was successfully accomplished via acclimatization in autoclaved perlite. Not all of the plantlets survived in soil that had not been autoclaved because of fungal infection, particularly in the region between the roots and leaves. Transgenic plants growing in soil were observed to be strongly resistant to Basta application.

Role of CT in left-sided acute appendicitis: case report

We present the computed tomographic findings in a case of left-sided acute appendicitis associated with midgut malrotation, which is a rare anomaly. The inflamed appendix was visualized as a tubular, fluid-filled, enhancing structure in the left lower quadrant. The entire colon was located in the left abdomen. The presence of a superior mesenteric vein rotation sign ascertained the presence of midgut malrotation. Computed tomography is useful not only in providing accurate diagnosis of left-sided appendicitis but also in detecting associated rotational anomalies, which may require separate surgical correction.

Subcutaneous Whole-Body Radionuclide Venography Using Tc-99m In Vivo Tagged Red Blood Cells

PURPOSE

The accurate diagnosis of deep vein thrombosis (DVT) is essential to prevent its complications and to initiate appropriate treatment. Doppler ultrasound (DUS), contrast venography, and intravenous radionuclide venography have been used for many years to detect DVT. However, obtaining venous access in the foot for injection of contrast agent can be difficult.

METHODS

The authors introduce the technique of subcutaneous radionuclide venography using Tc-99m in vivo tagged red blood cells and compare it with DUS, a widely used method. Sixty patients (120 lower extremities) underwent subcutaneous radionuclide venography and DUS.

RESULTS

The concordance rate was 94% in the femoral veins and 95% in the popliteal veins. Subcutaneous radionuclide venography revealed 10 iliac vein thromboses and 2 inferior vena cava thromboses that were not detected by DUS.

CONCLUSIONS

Subcutaneous radionuclide venography is a useful alternative method for detecting DVT. It is particularly valuable for evaluating DVT in the iliac veins and in the inferior vena cava.

Inhibition of growth of human breast carcinoma cells by an antisense oligonucleotide targeted to the transferrin receptor gene

Transferrin receptor expression is controlled by the amount of iron required by the cell to maintain its metabolism and therefore tumor cells in a highly proliferative state have a high density of transferrin receptors. In this study, phosphorothioated antisense TfR oligonucleotides (TfR-ODna) targeted to the sequences of TfR mRNA including the AUG initiation codon and the control sense chain (TfR-ODns) were synthesized. The rate of cellular DNA synthesis was determined by [3H]-thymidine incorporation. Administering TfR-ODna to three morphologically distinct breast cancer cell lines (MCF-7, T47D, and MDA-MB-231) and a normal breast cell line (MCF-12A) caused specific inhibition of tumor cell growth. The IC50 (50% inhibition of DNA synthesis) of the TfR-ODna for the MCF-7, T47D and MDA-MB-231 cells were 0.5, 0.5, and 1.0 microM, respectively, whereas the MCF-12A normal breast cells were about 30 times (IC50 of 30 microM) less sensitive to TfR-ODna than the breast cancer cells. The cytotoxicity of the antisense TfR-ODna was 10 to 60 times greater than that of the sense chain (TfR-ODns). TfR mRNA and protein synthesis were demonstrated by RT-PCR and immunohistochemical staining, respectively. Approximately 50% inhibition of the expression of TfR mRNA was observed when breast cancer cells were treated with 1 microM antisense TfR ODNa for 72 hrs but 1 microM antisense only caused 14% inhibition in normal breast cells. The decreased cytotoxicity and inhibition of TfR gene expression when the tumor cells were treated with the same concentration (1 microM) of TfR-ODns demonstrated the specificity of the TfR-ODna for blocking the target TfR gene. The combined cytotoxicities to human breast tumor MCF-7 cells of the antisense TfR-ODna and the iron chelator deferoxamine (DFO) or the ribonucleotide reductase inhibitor hydroxyurea were observed in this study. IC50s (50% inhibition of DNA synthesis) for DFO and hydroxyurea individually were 0.3 microM and 250 microM, respectively. The CalcuSyn program was used to determine the combined effects among the agents and synergism (Combined Indexes (CI) < 1) were found with the following two combinations: TfR-ODna (0.007 microM to 0.15 microM) with DFO (0.15 microM to 5 microM) and TfR-ODna (0.007 microM to 0.15 microM) with hydroxyurea (50 microM to 800 microM). However, inhibition by TfR-ODns was not synergistic with either DFO or hydroxyurea. The synergistic effects on inhibition of DNA synthesis between TfR-ODna and DFO or hydroxyurea suggest that inhibition of breast cancer cell growth by TfR-ODna is produced by depletion of iron pools that are required for DNA synthesis in tumor cells. The fact that TfR-ODna specifically decreases cell viability and proliferation, and reduces TfR mRNA and protein expression in human breast carcinoma cells without affecting normal breast cells, suggests that the antisense oligonucleotide to the transferrin receptor may be a novel therapeutic approach in breast cancer.

[Construction of the physical map of Pi-2(t), a blast resistance gene in rice]

In an effort to clone a rice blast resistance gene, Pi-2(t), a BAC contig consisting of 22 BAC clones covering the whole Pi-2(t) region, was constructed using marker-based chromosome landing and chromosome walking. The genetic span of this physical map is 8 cM, but the physical size is 925 kb. The physical map forms the base of further isolation and cloning of Pi-2(t) gene, it will provide new markers for molecular marker-aided selection of new blast resistance materials in rice.

Magnesium ion-mediated binding to tRNA by an amino-terminal peptide of a class II tRNA synthetase

Aspartyl-tRNA synthetase is a class II tRNA synthetase and occurs in a multisynthetase complex in mammalian cells. Human Asp-tRNA synthetase contains a short 32-residue amino-terminal extension that can control the release of charged tRNA and its direct transfer to elongation factor 1 alpha; however, whether the extension binds to tRNA directly or interacts with the synthetase active site is not known. Full-length human AspRS, but not amino-terminal 32 residue-deleted, fully active AspRS, was found to bind to noncognate tRNA(fMet) in the presence of Mg(2+). Synthetic amino-terminal peptides bound similarly to tRNA(fMet), whereas little or no binding of polynucleotides, poly(dA-dT), or polyphosphate to the peptides was found. The apparent binding constants to tRNA by the peptide increased with increasing concentrations of Mg(2+), suggesting Mg(2+) mediates the binding as a new mode of RNA.peptide interactions. The binding of tRNA(fMet) to amino-terminal peptides was also observed using fluorescence-labeled tRNAs and circular dichroism. These results suggest that a small peptide can bind to tRNA selectively and that evolution of class II tRNA synthetases may involve structural changes of amino-terminal extensions for enhanced selective binding of tRNA.

Expression of transferrin receptor and ferritin H-chain mRNA are associated with clinical and histopathological prognostic indicators in breast cancer

It is well known that iron plays an essential role in many biochemical reactions and that rapidly growing cells require more iron for their growth and metabolism than resting cells. Transferrin and its receptor are required for entry of iron into the cell. In contrast, ferritin is a cellular storage protein whose main function is to sequester excess ferric iron and thus prevent high concentrations of soluble ferric iron from becoming toxic to the cell. However, the clinical significance of both transferrin receptor and ferritin mRNA levels have not previously been described in tumors from breast cancer patients. In this study, tumor tissue mRNA levels of transferrin receptor and ferritin were quantitated on forty-two breast cancer patients. A highly sensitive non-radioisotopic cDNA polymerase chain reaction assay was used to quantitate expression of mRNA. The expression of glyceraldehyde-3-phosphate dehydrogenase served as the control. In the tumor tissue from the 42 breast cancer patients the transferrin receptor mRNA levels were significantly correlated to the ferritin H-chain mRNA levels (Spearman correlation r = 0.5433, p = 0.0002; Pearson correlation r = 0.6276, p < 0.0001). The level of amplified transferrin receptor complementary DNA was related to differentiation (ANOVA, p = 0.042) with poorly differentiated tumors having high levels of transferrin receptor mRNA. Further, the levels of amplified gene for ferritin heavy chain complementary DNA was directly related to axillary lymph nodes status (Student's t-test, p = 0.044), presence of metastatic disease (Student's t-test, p = 0.046) and clinical stage (stage I + stage II versus stage III + stage IV; Student's t-test, p = 0.0181). These results demonstrate that non-radioisotopic RT-PCR is a very sensitive method for determining mRNA levels in tumor tissue. Additionally, the quantitation of expression of transferrin receptor and ferritin heavy chain mRNA may be useful for assessing prognosis and guiding therapeutic decisions in breast cancer patients.

Vaccination with a mixed vaccine of autogenous and allogeneic breast cancer cells and tumor associated antigens CA15-3, CEA and CA125--results in immune and clinical responses in breast cancer patients

In breast cancer there is often overexpression of the breast cancer antigen CA15-3, the carcinoembryonic antigen (CEA) and the ovarian cancer antigen CA125, which makes them potential target antigens for immunotherapy. In this study, we used a multi-antigen vaccine, which included the following antigens: autologous breast cancer cells (AUTOC), allogeneic breast cancer MCF-7 cells (ALLOC), and the tumor associated antigens CA15-3, CEA and CA125, plus low doses of granulocyte/macrophage-colony-stimulating factor (GM-CSF) and interleukin 2 (IL-2). Forty-two breast cancer patients received weekly subcutaneous vaccination at the 1st, 2nd, 3rd, 7th, 11th and 15th weeks. Their lymphocyte proliferative responses to AUTOC, ALLOC, CA15-3, CEA and CA125 were tested in lymphocyte blastogenesis assays (LBA) before and after vaccination. The disease stage and serum CA15-3, CEA and CA125 concentrations were also determined pre- and post-vaccination. We found that the vaccine was safe, and the only major side effects were swelling at the site of injection, muscle pain, and weakness or fatigue. The vaccine induced a significant increase in post-vaccination lymphocyte proliferative responses to AUTOC, CA15-3, CEA and CA125 but not ALLOC, compared to pre-vaccination (p < 0.05, p < 0.01, p < 0.05, p < 0.01 and p > 0.05, respectively, a paired t Test). Computed tomography (CT), ultrasound or bone scan showed evidence of disease improvement in 2 (12%) patients after vaccination. Hepatic metastases were reduced in size and number and some actually disappeared one patient. Metastatic disease in the L5 vertebra and the skull decreased in size and some osteolytic sites completely healed in a second patient. In addition, 7 patients (44%) had stable disease and 7 patients (44%) had disease progression. We did not find vaccination significantly reduced serum tumor markers CA15-3, CEA and CA125 of these breast cancer patients. These results suggest that the vaccine mixture of autologous and allogeneic breast cancer cells and tumor associated antigens plus GM-CSF and IL-2 can be administered safely to breast cancer patients and there is evidence for improved immunity and clinical efficacy.

Selective cyclooxygenase-2 inhibitors: heteroaryl modified 1,2-diarylimidazoles are potent, orally active antiinflammatory agents

A series of heteroaryl modified 1,2-diarylimidazoles has been synthesized and found to be potent and highly selective (1000-9000-fold) inhibitors of the human COX-2. 3-Pyridyl derived COX-2 selective inhibitor (25) exhibited excellent activity in acute (carrageenan induced paw edema, ED(50) = 5.4 mg/kg) and chronic (adjuvant induced arthritis, ED(50) = 0.25 mg/kg) models of inflammation. The relatively long half-life of 25 in rat and dog prompted investigation of the pyridyl and other heteroaromatic systems containing potential metabolic functionalities. A number of substituted pyridyl and thiazole containing compounds (e.g., 44, 46, 54, 76, and 78) demonstrated excellent oral activity in every efficacy model evaluated. Several orally active diarylimidazoles exhibited desirable pharmacokinetics profiles and showed no GI toxicity in the rat up to 100 mg/kg in both acute and chronic models. The paper describes facile and practical syntheses of the targeted diarylimidazoles. The structure-activity relationships and antiinflammatory properties of a series of diarylimidazoles are discussed.

Reduction in serum IL-6 after vacination of breast cancer patients with tumour-associated antigens is related to estrogen receptor status

Elevated serum IL-6 concentrations have been associated with poor prognosis in a variety of cancers, and decreases in serum IL-6 concentrations have been reported after chemotherapy. We have demonstrated that serum IL-6 concentrations are elevated in breast cancer patients [normal women 0.7 +/- 2.5 pg/ml (n=36), breast cancer patients 38.3 +/- 138.7 pg/ml (n = 111)]. After vaccination of breast cancer patients with a combination of tumour-associated antigens and biological adjuvants (IL-2 and GM-CSF), the concentration of IL-6 decreased significantly (P<0.05) to 8.1 +/- 14.6 pg/ml (n=85). Other studies have shown that oestrogen suppresses IL-6 production in oestrogen receptor positive breast cancer cells. We have demonstrated that the decrease in IL-6 associated with vaccination is related to the oestrogen receptor status of the tumours from breast cancer patients, as a decrease in IL-6 from 124.0 +/- 267.5 pg/ml (n=26) to 6.2 +/- 11.0 pg/ml (n=34) only occurs in patients with oestrogen receptor negative tumours. The IL-6 concentration in breast cancer patients with oestrogen receptor positive tumours remained unchanged (9.5 pg/ml before vaccination, and 9.3 pg/ml after vaccination). These results suggest that postmenopausal women with oestrogen receptor negative breast cancers, who do not respond well to either hormonal therapy with tamoxifen or adjuvant chemotherapy, may have a significant response to vaccination with autologous tumour-associated antigens.

Troglitazone inhibits mitogenic signaling by insulin in vascular smooth muscle cells

Troglitazone (TRO) is an oral insulin-sensitizer that has direct effects on the vasculature to inhibit cell growth and migration. In vascular smooth muscle cells (VSMCs), insulin transduces a mitogenic signal that is dependent on the ERK1/2 MAP kinases. We examined the effects of TRO on this pathway and found that it inhibits mitogenic signaling. In quiescent VSMCs, insulin (1 microM) induced a 3.2-fold increase in DNA synthesis. TRO (1-20 microM) inhibited insulin-stimulated DNA synthesis by 72.8% at the maximal concentration. TRO at I and 10 microM had no significant effect on insulin-stimulated ERK1/2 activity. At 20 microM, however, TRO modestly enhanced insulin-stimulated ERK1/2 activity by 1.5-fold. ERKs transduce a mitogenic signal by phosphorylating transcription factors such as Elk-1. which regulate critical growth-response genes. We used GAL-Elk-1 expression plasmids to detect ERK-dependent activation of Elk-1. TRO at 1-20 microM potently inhibited insulin-stimulated, ERK1/2-dependent Elk-1 transcription factor activity. Neither early steps in insulin signaling nor the phosphatidylinositol 3-kinase (PI3K) branch of this pathway were affected by TRO, because it had no effect on IRS-1 phosphorylation, PI3K/IRS-1 association, or Akt phosphorylation. Because TRO is a known ligand for the nuclear transcription factor peroxisome proliferator-activated receptor gamma (PPARgamma), we tested two other ligands for this receptor, rosiglitazone (RSG) and 15-deoxy-delta12,14 prostaglandin J2 (15d-PGJ2). Both also inhibited insulin-induced DNA synthesis. In summary, these data show that TRO inhibits mitogenic signaling by insulin at a point distal of ERK1/2 activation, potentially by a PPARgamma-mediated inhibition of ERK-dependent phosphorylation and activation of nuclear transcription factors that regulate cell growth.

Doxorubicin-gallium-transferrin conjugate overcomes multidrug resistance: evidence for drug accumulation in the nucleus of drug resistant MCF-7/ADR cells

Development of multidrug resistance (MDR) in cancer cells decreases net doxorubicin (ADR) uptake as a result of increased efflux, increased intracellular sequestration, and decreased membrane permeability. In this study, we investigated whether conjugation of ADR to transferrin (Tf) could overcome MDR in breast cancer cells. The multidrug resistant MCF-7/ADR breast cancer cell line was over 1000-fold more resistant to ADR, than its parental MCF-7 cell line, as determined by 3[H]-thymidine assay. The MCF-7/ADR cell line also expressed both MDR1 and MRP genes, as detected by RT-PCR. The ADR was coupled using a glutaraldehyde technique to human transferrin saturated with either ferric chloride (Fe-Tf) or gallium nitrate (Ga-Tf). These conjugates were tested for cytotoxicity on both MCF-7 and MCF-7/ADR cells after 6 days of incubation. The doxorubicin-gallium-transferrin conjugate (ADR-Ga-Tf) exhibited approximately the same inhibitory effect as ADR on MCF-7 cells with IC50s of 2.34 x 10(-3) microM and 1.42 x 10(-3) microM, respectively. However in MCF-7/ADR cells ADR-Ga-Tf reversed resistance to free ADR and decreased 100-fold the IC50 from 8.98 microM with free ADR to 9.52 x 10(-2) microM. ADR-Fe-Tf was 10-fold more inhibitory to MCF-7/ADR cells than free ADR. Compared to Ga-Tf, ADR-Ga-Tf was 500- and 3000-fold more inhibitory to MCF-7 and MCF-7/ADR cells, respectively. These results demonstrated that ADR-Ga-Tf reverses resistance to free ADR and Ga-Tf in MCF-7/ADR cells. The distribution of ADR in both cell lines was examined by fluorescence microscopy. It was noted that ADR mainly accumulated in the cytoplasm around the nucleus in MCF-7/ADR cells, but in both the cytoplasm and nucleus of MCF-7 cells. However the conjugate of ADR-Ga-Tf allowed ADR to accumulate in the cytoplasm and nucleus of both the MCF-7/ADR and MCF-7 cells. Further investigation of MDR1 and MRP genes expression by RT-PCR demonstrated that Ga-Tf decreased expression of the MRP more than the MDR1 gene. Therefore the reversal of resistance to ADR by the ADR-Ga-Tf conjugate is mediated by the transferrin receptor transmembrane transport mechanism, redistribution of ADR into the nucleus of ADR resistant MCF-7/ADR cells and inhibition of MRP gene expression.

Production of tumor necrosis factor alpha in human T lymphocytes by staphylococcal enterotoxin B correlates with toxin-induced proliferation and is regulated through protein kinase C

The superantigen staphylococcal enterotoxin B (SEB) simultaneously binds both the major histocompatibility complex (MHC) class II receptor on monocytes and the T-cell receptor (TCR) on T lymphocytes, resulting in a range of cell responses including induction of tumor necrosis factor alpha (TNF-alpha). In this study, we have used mixed cultures of human peripheral blood monocytes and lymphocytes to investigate biochemical events controlling SEB induction of TNF-alpha. TNF-alpha production induced by SEB in mixed cultures is more closely associated with T cells than with monocytes: (i) a TCR-binding-site mutant of SEB (N23F) is less active in TNF-alpha induction than an MHC class II receptor-binding-site mutant (F44R), and (ii) flow cytometric analysis indicated that SEB induced TNF-alpha production in T cells but not in monocytes. Pretreatment of cells with inhibitors of signal transduction pathways was employed to further define events in SEB-induced TNF-alpha production. Neither protein kinase A inhibitors nor two protein tyrosine kinase inhibitors altered SEB-induced TNF-alpha production. In contrast, SEB induced protein kinase C (PKC) translocation, and pretreatment of cultures with inhibitors of PKC blocked TNF-alpha induction. Alteration of levels of diacylglycerol (DAG), an activator of PKC, by treatment with inhibitors of phospholipase C or DAG kinase also altered SEB-induced TNF-alpha production. These data suggest that PKC activation plays a critical role in SEB-induced TNF-alpha production in human T cells.

Cholera toxin induces tumor necrosis factor alpha production in human monocytes

Cholera toxin covalently ADP-ribosylates the a subunit of Gs proteins. The modified Gsalpha activates adenylate cyclase and leads to a dramatic increase in intracellular cAMP. The effect of cholera toxin on the production of tumor necrosis factor (TNF-alpha), a critical mediator of toxicity for a number of bacterial and viral infections, has not been examined. Here we show that cholera toxin stimulated human monocytes to secrete TNF-alpha. The subunit A of cholera toxin alone also induced TNF-alpha production, suggesting that TNF-alpha production is mediated through ADP-ribosylation activity of the toxin. Inhibitors of ADP-ribosylation such as 3-aminobenzamide and niacinamide blocked TNF-alpha induction. However, cyclic AMP analogs and adenylate cyclase activator forskolin did not induce TNF-alpha production in monocytes, suggesting that TNF-alpha induction is independent of cAMP. Furthermore, cholera toxin-induced TNF-alpha production was suppressed by protein kinase C inhibitors H7 and sphingosine and by phospholipase C inhibitors U73122 and ET-18-OCH3, suggesting that PLC and PKC mediate TNF-alpha induction. Cholera toxin-mediated induction of TNF-alpha occurs at the transcription level as demonstrated by the time-dependent expression of TNF-alpha mRNA. These results raise the possibility that TNF-alpha may play an important role in cholera toxin-mediated toxicity and demonstrate that cholera toxin activates TNF-alpha production through PLC-dependent and cAMP-independent pathways. The probable mechanisms of signal transduction from cholera toxin to PLC in monocytes will be discussed.

Distributing working versions of published mathematical models for biological systems via the Internet

Mathematical models are useful tools for investigating complex systems. By representing physiological systems as models, theories can be tested quantitatively against data from the system. Models can be used to explore new theories prior to experimentation and to design studies to optimize experimental resources. They can also be used as teaching tools to illustrate physiochemical principles. In spite of their usefulness and the time invested in developing models, published models are often underused due to the difficulty in obtaining working versions of the model. To address this problem we have designed a library for mathematical models of biological systems on the Internet. The library contains published models of biological systems in formats compatible with several modeling packages, from the fields of physiology, metabolism, endocrinology, biochemistry, and chemistry. The models can be viewed graphically, model solutions can be viewed as plots against data, and models can be downloaded to be run with software on the user's own system. The address of the library is: http://biomodel.georgetown.edu/model/ Investigators are invited to submit working versions of published models to the library. Models can be submitted electronically at the time a manuscript is accepted for publication. As journals go online, articles containing models can be linked to working versions of the models in the library. By increasing access to working versions of models, more of the investment in kinetic studies and model development can be realized.

Regenerative ability of somatic single and multiple embryos from cotyledons of Korean ginseng on hormone-free medium

Cotyledon explants of Korean ginseng (Panax ginseng C. A. Meyer) produced somatic embryos directly on growth regulator-free medium. Somatic embryos developed as either multiple or single-state forms, depending on the degree of maturity of the cotyledons. Cotyledon explants from midmature zygotic embryos formed multiple embryos, while cotyledons from fully mature zygotic embryos formed single embryos. Somatic single embryos regenerated into normal plantlets with both roots and shoots, while multiple embryos did not produce roots but regenerated only into multiple shoots. In full-strength MS basal medium, the root growth of plantlets derived from single embryos was weak compared to that of shoots. Deletion of ammonium nitrate from the MS medium promoted the root growth of the plantlets. The ginseng plants with well-developed shoots and roots regenerated from single embryos were successfully acclimatized in a greenhouse when they were planted in soil.

Serum osteocalcin levels of normal children in Taiwan

Osteocalcin is mainly secreted by osteoblasts, and then diffuses into blood which can be detected by several experimental methods. This study determined the osteocalcin level by solid phase fluorescent immunosorbent assay (Pharmacia CAP; Sweden), a well-established and accurate laboratory method for determining the minor concentration of substances in blood. A total of 332 healthy children were enrolled in the study, including 176 boys and 156 girls ranging in age from one to fifteen years. It was concluded that (1) quantitative osteocalcin (OCs) value varies between 30.2 to 41.0 ng/ml; (2) there is an incremental tendency in both sexes until puberty; (3) girls generally have a higher osteocalcin level than boys before mid-puberty (2-12 years old). The differences are statistically significant.

Distribution and changes of reserve materials in cotyledon cells of Panax ginseng related to direct somatic embryogenesis and germination

Cotyledon explants from zygotic embryos of Panax ginseng produced somatic embryos on Murashige and Skoog basal medium without growth regulators. Somatic embryos developed directly from epidermal cells at the cotyledon base. Somatic embryos were always formed from the side of the cotyledon opposite to the one attached to the medium surface regardless of cotyledon orientation. The frequency of somatic embryo formation from the abaxial epidermis (66%) was much higher than that from the adaxial epidermis (12%). Differences in embryogenic response were likely related to cell structure. Abaxial epidermal cells were filled with reserve materials (lipid bodies), while adaxial epidermal cells were devoid of any prominent reserves. During germination, the reserve materials in the cells of the cotyledons disappeared rapidly. At the same time, the competency of somatic embryo formation from cotyledon explants declined rapidly to zero. Upon culture of the cotyledon explants (for somatic embryo induction), lipid bodies slowly disappeared, but starch grains accumulated prominently. Reserve materials disappeared after commencement of embryogenic cell division. During germination, lipid bodies rapidly disappeared, and chloroplasts developed instead of starch grains.

Developmental and structural aspects of somatic embryos formed on medium containing 2,3,5-triiodobenzoic acid

Cotyledon explants of ginseng (Panax ginseng C.A. Meyer) zygotic embryos produced somatic embryos at a high rate (68%) on medium without any growth regulators. Under this culture condition, apparent polar somatic embryogenesis occurred near the basal-excised portion of the cotyledons. When the cotyledon explants were cultured on medium containing 2,3,5-triiodobenzoic acid (TIBA), an auxin polar-transport inhibitor, the frequency of somatic embryo formation markedly decreased and was completely inhibited on medium containing 20 µM TIBA. On medium containing 5-10 µM, somatic embryos developed sporadically on the surface of the cotyledons and had a normal embryo axis but jar-shaped cotyledons. Embryos with jar-shaped cotyledons were also observed to occur at a high frequency when the early globular embryos formed on hormone-free medium were transferred to medium containing 20 µM TIBA. From these results, it was deduced that endogenous auxin in the cotyledon explants plays an important role in the induction of somatic embryos and that the cotyledon development in somatic embryos is also related to the polar transport of endogenous auxin.

Polymorphism, distribution, and segregation of AFLP markers in a doubled haploid rice population

We exploited the newly developed amplified fragment length polymorphism (AFLP) technique to study the polymorphism, distribution and inheritance of AFLP markers with a doubled haploid rice population derived from 'IR64'/'Azucena'. Using only 20 pairs of primer combinations, we detected 945 AFLP bands of which 208 were polymorphic. All 208 AFLP markers were mapped and distributed over all 12 chromosomes. When these were compared with RFLP markers already mapped in the population, we found the AFLP markers to be highly polymorphic in rice and to follow Mendelian segregation. As linkage map of rice can be generated rapidly with AFLP markers they will be very useful for marker-assisted backcrossing.

Isolation and identification of metabolites of leukotriene A4 hydrolase inhibitor SC-57461 in rats

The metabolic fate of SC-57461, N-methyl-N-[3-[4-(phenylmethyl)-phenoxy]propyl]-beta-alanine, a potent and specific inhibitor of the leukotriene A4 hydrolase, was determined by LC/MS/MS, NMR and GC/MS in male Sprague-Dawley rats. The major metabolites of SC-57461 in rats were the desmethyl metabolite, the hydroxylated metabolite, the N-oxide metabolite, the hydroxylamine metabolite, and the propionic acid metabolite. The N-oxide metabolite was found to be stable in the rat plasma and urine, but was unstable in most organic solvents (methanol, acetonitrile, and methylene chloride, etc.) because of the classic Cope reaction of the N-oxide, which led to the formation of the corresponding hydroxylamine product and acrylic acid. The hydroxylamine metabolite and acrylic acid were reactive in the biomatrix and could not be isolated in the in vivo samples. However, formation of the hydroxylamine metabolite and acrylic acid from the N-oxide metabolite in methylene chloride was verified by NMR. The propionic acid metabolite was found to be the common metabolite shared by SC-57461, N-oxide metabolite, as well as the hydroxylamine metabolite, which suggested a sequential metabolism of SC-57461 in rats. The ultimate fate of the propionic acid metabolite was incorporation into rat glycerolipid metabolism as a result of its structural similarity to aryl-substituted propionic acid, a known class of compounds that can be incorporated into rat glycerolipid metabolism. Finally, the isolated hydroxylated metabolite and the N-desmethyl metabolite were found to have excellent inhibitory effects toward leukotriene A4 hydrolase and therefore were the major active metabolites of SC-57461 in rats.

Giant hepatic hemangioma studied with intravenous total body arteriography technique. A case report

Hepatic hemangiomas are the most common benign tumors of the liver. They are usually single, small, and asymptomatic. However, giant hepatic hemangiomas have been reported in the past, usually detected as incidental findings. Radionuclide blood pool imaging studies are used to confirm the presence of a hemangioma. This report describes a case of a giant hepatic hemangioma detected using intravenous total-body arteriography, done as a part of radionuclide blood pool hemangioma study. This simple addition to the regular RBC blood pool hemangioma study helps to determine the size of the liver in the early arterial phase and shows obvious increased blood pool activity in the delayed phase. It is also useful in detecting lesions in other parts of the body when present.

Ubiquitinylation of transcription factors c-Jun and c-Fos using reconstituted ubiquitinylating enzymes

Recombinant c-Jun and c-Fos were ubiquitinylated by the ubiquitin carrier enzymes E214K, E220K, or E232K in the presence of the ubiquitin-activating enzyme, E1. Addition of ubiquitin protein ligase E3 substantially enhanced the E214K-mediated ubiquitinylation of c-Jun and c-Fos. Truncated c-Jun and c-Fos mutant proteins including wbJun and wbFos were also ubiquitinylated under the same conditions, suggesting the sites of ubiquitinylation are located within the dimerization and DNA binding domains of c-Jun and c-Fos. The E3-dependent ubiquitinylation of c-Jun was inhibited upon the heterodimerization of c-Jun with c-Fos. Further addition of E220K significantly enhanced ubiquitinylation of c-Jun in the heterodimer suggesting a regulatory role of E220K. Polyubiquitinylated c-Jun, wbFos, and wbJun, but not E220K-ubiquitinylated c-Jun, were readily degraded by the ATP-dependent 26 S multicatalytic proteases. These results suggest that the temporal control of c-Jun and c-Fos may be regulated through the ubiquitinylation pathways, and the ubiquitinylation of c-Jun and c-Fos may in turn be regulated in response to the heterodimerization between them and the cooperation between E220K and E3 mediated polyubiquitinylation.

The synthesis and biological activities of oligodeoxynucleotides that are covalently linked to psoralen at their 5' ends

Four oligodeoxynucleotides (15-mers), designated 13 through 16, and the corresponding conjugates, designated 17 through 20, in which psoralen was covalently linked to the 5' end of each oligonucleotide were synthesized. Compounds 16 and 20 contained a sequence that was complementary to part of the first four codons and the upstream sequence close to the ribosome-binding site of c-Ha-ras mRNA. Compounds 16 and 20 inhibited the growth of cells that had been transformed by the c-Ha-ras plasmid, with accompanying suppression of the expression of the activated c-Ha-ras oncogene. The antisense oligonucleotides 16 and 20 also appeared to cause partial reversion of the major phenotypic characteristics of transformed cells, which included inhibition of anchorage-independent growth. Compound 20, which contained psoralen, was a more efficient inhibitor of the growth of transformed cells than compound 16 without psoralen, a result that suggests psoralen might have increased the ability of the oligodeoxynucleotides to enter the cells.

Determination of protein binding by in vitro charcoal adsorption

Certain compounds such as SC-52151 have extensive nonspecific adsorption to the ultrafiltration devices or to dialysis membranes and therefore can not be measured by the conventional ultrafiltration or equilibrium dialysis methods. A new method based on charcoal adsorption was developed to overcome this difficulty. Unlike many conventional methods, which are based on the separation of free drug from bound drug under equilibrium conditions, the new method is operated under nonequilibrium conditions and involves measuring the time course of decline of the percentage of bound drug remaining in plasma while the free drug is being removed by charcoal adsorption. Theoretical aspects of the method and the data processing procedure are presented. SC-98A, a compound with minimal nonspecific adsorption to the ultrafiltration membrane, was used to demonstrate the applicability of this method against the ultrafiltration method. Using this method, the protein binding of SC-52151 in human plasma at 1.0 microgram/ml was determined to be in the range of 91.4-97.7% at room temperature.

Characterization of a novel N-terminal peptide in human aspartyl-tRNA synthetase. Roles in the transfer of aminoacyl-tRNA from aminoacyl-tRNA synthetase to the elongation factor 1 alpha

The kinetics of the N-terminal 32 residue-deleted human aspartyl-tRNA synthetase (hDRS delta 32) was analyzed. The kinetics of aspartyl-adenylate formation and Asp-tRNA synthesis by hDRS delta 32 were indistinguishable from those of hDRS. However, the dissociation of Asp-tRNA from hDRS delta 32 was much faster than that of hDRS. Unlike hDRS delta 32-catalyzed aspartylation of tRNA was not affected by the elongation factor 1 alpha. Two N-terminal peptides of hDRS, hDRS(T5-E26) and hDRS(D12-R27), were synthesized. Both peptides bind to tRNA-Sepharose. Both peptides, hDRS(T5-E26) and hDRS(D12-R27), are monomeric and oligomerize at high peptide concentration or in 50% propylene glycol. The peptide hDRS(T5-E26) showed little alpha-helical content as analyzed by CD spectroscopy, while hDRS(D12-R27) showed appreciable alpha-helical contents in nonpolar solvents. These results suggest that the N terminus in hDRS may mediate the slow release of Asp-tRNA and facilitate the interaction of the hDRS.Asp-tRNA complex with the elongation factor 1 alpha. The demonstration of alpha-helix formation of the hDRS N-terminal peptide is consistent with the hypothetical amphiphilic helix of the N-terminal extension in hDRS. A model for the transfer of Asp-tRNA from hDRS to elongation factor 1 alpha is presented.

Mechanisms of the transfer of aminoacyl-tRNA from aminoacyl-tRNA synthetase to the elongation factor 1 alpha

Aspartylation of mammalian tRNAAsp by bacteria-expressed human aspartyl-tRNA synthetase (hDRS) was examined. The kinetics of the aspartylation of tRNA was consistent with the following reaction pathway, [formula: see text] where E, represents aspartyl-tRNA synthetase. A set of rate constants was obtained which fit single turnover time courses at varying concentrations of the enzyme, tRNA, and AMP using the SAAM program. The dissociation of Asp-tRNA (k3) was found to be rate limiting. The elongation factor 1 alpha (EF1 alpha) and GTP stimulated the hDRS aspartylation. The stimulation depended on the presence of both EF1 alpha and GTP. Kinetic analysis indicated that EF1 alpha formed a complex with the hDRS-Asp-tRNA complex and stimulated the dissociation of Asp-tRNA. In the presence of 0.5 M NH4Cl, which enhances the binding of Asp-tRNA by EF1 alpha, hDRS-bound Asp-tRNA can be transferred directly to EF1 alpha. The implications of these results on the function of the multi-tRNA synthetase complex will be discussed.

Selenocysteine tRNA and serine tRNA are aminoacylated by the same synthetase, but may manifest different identities with respect to the long extra arm

Selenocysteine (Sec) tRNA([Ser])Sec donates Sec to protein, but interestingly, this amino acid is synthesized on tRNA which is first aminoacylated with serine. Thus, the identity elements in tRNA([Ser])Sec for aminoacylation correspond to elements for seryl-tRNA synthetase recognition. As tRNA([Ser])Sec has low homology to the tRNA(Ser) isoacceptors, it would seem then that the identity elements in tRNA([Ser])Sec involve (1) very specific sequences, (2) conformational features, and/or (3) different points or domains for tRNA[Ser]Sec:synthetase and tRNASer:synthetase recognition. Initially, we confirmed that the same synthetase aminoacylates both tRNAs by showing that a mutant tRNA[Ser]Sec which has a blocked 3'-terminus is a competitive inhibitor of tRNASer aminoacylation with a partially purified and a highly purified seryl-tRNA synthetase preparation. The discriminator base (base G73) is essential for aminoacylation of tRNA([Ser])Sec and tRNA(Ser), while the long extra arm plays an important role which seems to be orientation- and length-specific in tRNA(Ser) and, in addition, may manifest sequence specificity in tRNA([Ser])Sec. This difference in the tRNA recognition specificity is discussed. The acceptor stem, DHU stem, and T phi C stem contribute to the recognition process, but to a lesser extent than the discriminator base and the long extra arm.

Expression of human aspartyl-tRNA synthetase in COS cells

Mammalian aspartyl-tRNA synthetase (DRS) occurs in a multi-enzyme complex of aminoacyl-tRNA synthetases, while DRS exists as free soluble enzymes in bacteria and yeast. The properties of human DRS transient expressed in COS cells were examined. After transfection of COS cells with the recombinant plasmids pSVL-63 that contained hDRS cDNA coding and non-coding sequences, and pSV-hDRS where the non-coding sequences were deleted, DRS in the transfected COS cells significantly increased compared to mock transfected cells. COS cells transfected with pSV-hDRS delta 32 that contained N-terminal 32 residue-coding sequence deleted hDRS cDNA showed no increase in DRS activity. Northern blot analysis showed that concentrations of corresponding mRNAs of hDRS and hDRS delta 32 were greatly enhanced in transfected cells. The increases in the level of the transcripts were much higher than those of the corresponding proteins. Gel filtration analysis showed that hDRS in pSV-hDRS transfected cells expressed as a low molecular weight form of hDRS and pSV-hDRS delta 32 transfected cells did not. Epitope tagging and indirect immunofluorescence microscopy was used to localize hDRS. Both hDRSmyc and hDRS delta 32myc were localized in the cytoplasm and showed diffused patterns. These results showed that hDRS has little tendency to aggregate in vivo and suggested that the N-terminal extension in hDRS was not involved in the expression and sub-cellular localization of hDRS, but may play a role in the maintenance of enzymatic activity of hDRS in COS cells.