Genome-Wide Association Study for the Genetic Determinants of Thiopurine Methyltransferase Protein Expression in Human Livers and Racial Differences

INTRODUCTION

Polymorphisms in the Thiopurine S-Methyltransferase (TPMT) gene are associated with decreased TPMT activity, but little is known about their impact on TPMT protein expression in the liver. This project is to conduct a genome-wide association study (GWAS) to identify single nucleotide polymorphisms (SNPs) associated with altered TPMT protein expression in human livers and to determine if demographics affect hepatic TPMT protein expression.

METHODS

Human liver samples (n = 287) were genotyped using a whole genome genotyping panel and quantified for TPMT protein expression using a Data-Independent Acquisition proteomics approach.

RESULTS AND DISCUSSION

Thirty-one SNPs were found to be associated with differential expression of TPMT protein in the human livers. Subsequent analysis, conditioning on rs1142345, a SNP associated with the TPMT*3A and TPMT*3C alleles, showed no additional independent signals. Mean TPMT expression is significantly higher in wildtype donors compared to those carrying the known TPMT alleles, including TPMT*3A, TPMT*3C, and TPMT*24 (0.107 ± 0.028 vs. 0.052 ± 0.014 pmol/mg total protein, P = 2.2 × 10-16). After removing samples carrying the known TPMT variants, European ancestry donors exhibited significantly higher expression than African ancestry donors (0.109 ± 0.026 vs. 0.090 ± 0.041 pmol/mg total protein, P = 0.020).

CONCLUSION

The GWAS identified 31 SNPs associated with TPMT protein expression in human livers. Hepatic TPMT protein expression was significantly lower in subjects carrying the TPMT*3A, TPMT*3C, and TPMT*24 alleles compared to non-carriers. European ancestry was associated with significantly higher hepatic TPMT protein expression than African ancestry, independent of known TPMT variants.

Identification of regulatory variants of carboxylesterase 1 (CES1): A proof-of-concept study for the application of the Allele-Specific Protein Expression (ASPE) assay in identifying cis-acting regulatory genetic polymorphisms

It is challenging to study regulatory genetic variants as gene expression is affected by both genetic polymorphisms and non-genetic regulators. The mRNA allele-specific expression (ASE) assay has been increasingly used for the study of cis-acting regulatory variants because cis-acting variants affect gene expression in an allele-specific manner. However, poor correlations between mRNA and protein expressions were observed for many genes, highlighting the importance of studying gene expression regulation at the protein level. In the present study, we conducted a proof-of-concept study to utilize a recently developed allele-specific protein expression (ASPE) assay to identify the cis-acting regulatory variants of CES1 using a large set of human liver samples. The CES1 gene encodes for carboxylesterase 1 (CES1), the most abundant hepatic hydrolase in humans. Two cis-acting regulatory variants were found to be significantly associated with CES1 ASPE, CES1 protein expression, and its catalytic activity on enalapril hydrolysis in human livers. Compared to conventional gene expression-based approaches, ASPE demonstrated an improved statistical power to detect regulatory variants with small effect sizes since allelic protein expression ratios are less prone to the influence of non-genetic regulators (e.g., diseases and inducers). This study suggests that the ASPE approach is a powerful tool for identifying cis-regulatory variants.

Tissue- and cell-expression of druggable host proteins provide insights into repurposing drugs for COVID-19

Several human host proteins play important roles in the lifecycle of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Many drugs targeting these host proteins have been investigated as potential therapeutics for coronavirus disease 2019 (COVID-19). The tissue-specific expressions of selected host proteins were summarized using proteomics data retrieved from the Human Protein Atlas, ProteomicsDB, Human Proteome Map databases, and a clinical COVID-19 study. Protein expression features in different cell lines were summarized based on recent proteomics studies. The half-maximal effective concentration or half-maximal inhibitory concentration values were collected from in vitro studies. The pharmacokinetic data were mainly from studies in healthy subjects or non-COVID-19 patients. Considerable tissue-specific expression patterns were observed for several host proteins. ACE2 expression in the lungs was significantly lower than in many other tissues (e.g., the kidneys and intestines); TMPRSS2 expression in the lungs was significantly lower than in other tissues (e.g., the prostate and intestines). The expression levels of endocytosis-associated proteins CTSL, CLTC, NPC1, and PIKfyve in the lungs were comparable to or higher than most other tissues. TMPRSS2 expression was markedly different between cell lines, which could be associated with the cell-dependent antiviral activities of several drugs. Drug delivery receptor ICAM1 and CTSB were expressed at a higher level in the lungs than in other tissues. In conclusion, the cell- and tissue-specific proteomics data could help interpret the in vitro antiviral activities of host-directed drugs in various cells and aid the transition of the in vitro findings to clinical research to develop safe and effective therapeutics for COVID-19.

Effect of CES1 genetic variation on enalapril steady-state pharmacokinetics and pharmacodynamics in healthy subjects

AIMS

Enalapril is a prodrug and needs to be activated by carboxylesterase 1 (CES1). A previous in vitro study demonstrated the CES1 genetic variant, G143E (rs71647871), significantly impaired enalapril activation. Two previous clinical studies examined the impact of G143E on single-dose enalapril PK (10 mg); however, the results were inconclusive. A prospective, multi-dose, pharmacokinetics and pharmacodynamics (PK/PD) study was conducted to determine the impact of the CES1 G143E variant on enalapril steady-state PK and PD in healthy volunteers.

METHODS

Study participants were stratified to G143E non-carriers (n = 15) and G143E carriers (n = 6). All the carriers were G143E heterozygotes. Study subjects received enalapril 10 mg daily for seven consecutive days prior to a 72 hour PK/PD study. Plasma concentrations of enalapril and its active metabolite enalaprilat were quantified by an established liquid chromatography-tandem mass spectrometry (LC-MS/MS) method.

RESULTS

The CES1 G143E carriers had 30.9% lower enalaprilat C_max (P =  0.03) compared to the non-carriers (38.01 vs. 55.01 ng/mL). The carrier group had 27.5% lower AUC_0-∞ (P =  0.02) of plasma enalaprilat compared to the non-carriers (374.29 vs. 515.91 ng*h/mL). The carriers also had a 32.3% lower enalaprilat-to-enalapril AUC_0-∞ ratio (P =  0.003) relative to the non-carriers. The average maximum reduction of systolic blood pressure in the non-carrier group was approximately 12.4% at the end of the study compared to the baseline (P =  0.001). No statistically significant blood pressure reduction was observed in the G143E carriers.

CONCLUSIONS

The CES1 loss-of-function G143E variant significantly impaired enalapril activation and its systolic blood pressure-lowering effect in healthy volunteers.

Correction to: Acute respiratory failure and the kinetics of neutrophil recovery in pediatric hematopoietic cell transplantation: a multicenter study

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Acute respiratory failure and the kinetics of neutrophil recovery in pediatric hematopoietic cell transplantation: a multicenter study

In this multicenter study, we investigated the kinetics of neutrophil recovery in relation to acuity and survival among 125 children undergoing allogeneic hematopoietic cell transplantation (allo-HCT) who required invasive mechanical ventilation (IMV). Recovery of neutrophils, whether prior to or after initiation of IMV, was associated with a significantly decreased risk of death relative to never achieving neutrophil recovery. A transient increase in acuity (by oxygenation index and vasopressor requirements) occurred among a subset of the patients who achieved neutrophil recovery after initiation of IMV; 61.5% of these patients survived to discharge from the intensive care unit (ICU). Improved survival among patients who subsequently achieved neutrophil recovery on IMV was not limited to those with peri-engraftment respiratory distress syndrome. The presence of a respiratory pathogen did not affect the risk of death while on IMV but was associated with an increased length of IMV (p < 0.01). Among patients undergoing HCT who develop respiratory failure and require advanced therapeutic support, neutrophil recovery at time of IMV and/or presence of a respiratory pathogen should not be used as determining factors when counseling families about survival.

Internally displaced human resources for health: villager health worker partnerships to scale up a malaria control programme in active conflict areas of eastern Burma

Approaches to expand malaria control interventions in areas of active conflict are urgently needed. Despite international agreement regarding the imperative to control malaria in eastern Burma, there are currently no large-scale international malaria programmes operating in areas of active conflict. A local ethnic health department demonstrated that village health workers are capable of implementing malaria control interventions among internally displaced persons (IDPs). This paper describes how these internally displaced villagers facilitated rapid expansion of the programme. Clinic health workers received training in malaria diagnosis and treatment, vector control and education at training sites along the border. After returning to programme areas inside Burma, they trained villagers to perform an increasingly comprehensive set of interventions. This iterative training strategy to increase human resources for health permitted the programme to expand from 3000 IDPs in 2003 to nearly 40,000 in 2008. It was concluded that IDPs are capable of delivering essential malaria control interventions in areas of active conflict in eastern Burma. In addition, health workers in this area have the capacity to train community members to take on implementation of such interventions. This iterative strategy may provide a model to improve access to care in this population and in other conflict settings.

Genotypic and allelic frequencies of SULT1A1 polymorphisms in women receiving adjuvant tamoxifen therapy

Human sulfotransferase 1A1 (SULT1A1) is involved in the metabolism of a number of substances including 4-hydroxytamoxifen. It has been shown that patients who are homozygous for the variant SULT1A1 *2/*2 have lower catalytic activity. Previous data has suggested that patients with this particular genotype may be at a greater risk of developing breast cancer or not responding to tamoxifen therapy. To date, there is no data within the Hispanic population on the genotypic and allelic frequencies of the SULT1A1 gene. Two hundred and ninety-six patients were genotyped by either restriction fragment length polymorphism (RFLP) or Pyrosequencing for the SULT1A1 exon 7 polymorphism. The genotypic frequency was 0.47 (*1/*1), 0.40 (*1/*2) and 0.13 (*2/*2) in Caucasians and 0.37 (*1/*1), 0.45 (*1/*2) and 0.18 (*2/*2) in Hispanics. Although Hispanics have a higher genotypic frequency of variant genotypes this difference was not statistically significant (p=0.26). SULT1A1 genotype did not correlate with any prognostic or predictive markers associated with breast cancer. Future evaluations will assess the functional significance of this polymorphism on survival.

Evaluation of an educational intervention to increase cultural competence among registered nurses

The purpose of this two group intervention study (N = 94) was to determine if RNs who participated in "culture school" improved levels of cultural competence to a greater extent than RNs who attended nursing informatics classes. The Giger and Davidhizar Transcultural Assessment Model/Theory (GDTAMT) was the study's theoretical foundation (Giger & Davidhizar, 1995). A sample of 94 participants, was identified from a randomized group of all Jefferson County, Alabama RNs. Randomly assigned participants (stratified by race) experienced 8.5 hours of either culture school or nursing informatics classes and completed survey tools in three phases (pre-intervention, immediate post intervention, three week follow-up). The Cultural Self-Efficacy Scale (CSES) by Bernal and Froman (1987), knowledge base questions by Rooda (1990), and demographic profiles were used. Concepts empirically measured using these tools were analyzed by transcultural nursing experts for their congruence with GDTAMT. Using repeated measures analyses of convariance (race), significant differences between groups for both scales were found. Culture school participants demonstrated significantly more cultural self-efficacy and cultural knowledge, and these improvements remained during phase three. Further research is recommended to allow for greater generalizability of findings, an examination of client perceptions, and actual nurse behaviors.

Catechins are bioavailable in men and women drinking black tea throughout the day

Tea consumption has been associated with reduced risk of both cancer and cardiovascular disease in population studies, but clinical data demonstrating bioavailability of the individual catechins and other polyphenolic components of tea are limited. This study assessed the apparent bioavailability of the prominent catechins from black tea in humans drinking tea throughout the day. After 5 d of consuming a low flavonoid diet, subjects drank a black tea preparation containing 15.48, 36.54, 16.74, and 31.14 mg of (-)-epigallocatechin (EGC), (-)-epicatechin (EC), (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG), respectively, at four time points (0, 2, 4 and 6 h). Blood, urine and fecal specimens were collected over a 24- to 72-h period and catechins were quantified by HPLC with coularray detection. Plasma concentrations of EGC, EC and EGCG increased significantly relative to baseline (P < 0.05). Plasma EGC, EC and EGCG peaked after 5 h, whereas ECG peaked at 24 h. Urinary excretion of EGC and EC, which peaked at 5 h, was increased relative to baseline amounts (P < 0.05) and fecal excretion of all four catechins was increased relative to baseline (P < 0.05). Approximately 1.68% of ingested catechins were present in the plasma, urine and feces, and the apparent bioavailability of the gallated catechins was lower than the nongallated forms. Thus, catechins were bioavailable. However, unless they are rapidly metabolized or sequestered, the catechins appeared to be absorbed in amounts that were small relative to intake.

Health of America's newcomers

Newcomer health and health care are policy issues with major outcomes of cost shifting and enormous consequences for newcomers and the community health nurses who promise them care. Newcomers are persons entering U.S. borders who could be asylees, refugees, immigrants, legal or illegal aliens, migrants, international adoptees, and others. Described in this article are the role federalism has played on the interplay among policymakers regarding newcomer health. Also addressed is newcomer health policy, including immigration policies, and newcomer health issues such as infectious diseases and questionable health care. Additional newcomer health issues such as newcomers at high risk for health problems, issues of access to care for newcomers, and welfare reform policies are discussed. Newcomer health and special interest group activities such as those from medicine and nursing are also addressed. Finally, meaningful options and possible solutions for newcomer health care concerns are identified and shared.

Mentoring benefits and issues for public health nurses

New public health nurses (PHNs) move from novice to expert status with enormous expectations from their organization, their peers, and themselves. These expectations lead to stress that may be beyond the level of endurance. Mentoring is an important answer to this problem. Mentoring is the greatest gift PHNs can give to each other, especially for PHNs who self-identified themselves as minority cultural group members. This article describes definitions, roles, benefits, and responsibilities of mentors and mentees and includes mentoring concerns, current and proposed mentoring programs, and mentoring issues for gender and race. Organizational mentoring programs can be created that will facilitate the development of mentoring relationships. These programs help experienced PHNs bridge the gap between the theory and reality of nursing for themselves and inexperienced colleagues.

SPIKEII: an integrate-and-fire AVLSI chip

We present the SPIKEII chip, an integrate-and-fire neural network chip with programmable synapses implemented in analogue VLSI. It is the successor to the SPIKEI chip. We describe the circuitry, and show some results using networks of integrate-and-fire neurons.

Silicon cellular morphology

We describe a design technique for neuromorphic engineering that exploits both Mead's notion of physical equivalence between transistors and ion channels and the intrinsic properties of the materials of which transistors are composed. This is in contrast to the "algorithmic" design technique in common use. A "physical" design technique allows us to emphasise the morphology of cells. We hope to use this in an exploration of the effect of cell morphology upon function.

Cultural competence for nurses: canonical correlation of two culture scales

As the diversity of the US residential population increases, healthcare professionals need to recognize the importance of culturally competent care on health outcomes of individuals and communities. The purpose of this descriptive correlational pilot study (N = 51) was to describe the relationship among scores and sub-scores on scales measuring concepts of cultural competence. An additional purpose was to develop reliability and validity data on each of three culture scales for the population of hospital based registered nurses. Each of the scales had previously reported reliability and validity data but were administered to populations potentially different from southern-based, hospital-employed RNs. A large medical center located in Southeastern US was chosen as the study's site due to its diverse staff and client base. The Giger and Davidhizar Transcultural Assessment Model and Theory was the theoretical foundation for the study and Cultural Self-Efficacy Scale (CSES), Cultural Attitude Scale as developed by Bonaparte (1977, 1979) and modified by Rooda (1990, 1992) (CAS-Modified), and knowledge base questions (Rooda, 1990) were the chosen instruments. For this group of hospital based RNs, the reliability analysis--scale (Alpha) for the 58 item CSES was .9778. The reliability analysis (Alpha) for the 22 knowledge base questions was .6038 and .6412 for the 40 item CAS-M. Canonical correlation analysis was performed between a set of attitude variables and a set of self efficacy variables using SPSS (1995). Both sets of variables demonstrated statistically significant relationships (at an a priori alpha of .05) to each other (with an approximate Eta squared value for practical significance of .336), providing sufficient evidence to reject the non-relationship null hypothesis. For this sample and for these data, cultural self-efficacy toward Asian, Black, Hispanic clients, and self-efficacy regarding nursing skills when caring for diverse clients related to cultural attitudes and cultural self-efficacy. Nursing care, cultural health beliefs, and cultural health attitudes related to attitudes toward care of diverse clients. Both sets of variables related to each other as qualities of culturally competent nursing care.

Are we reaching the healthcare consumer?

With the diversity of our communities and waiting rooms increasing, can we continue to justify the lack of diversity among healthcare professionals? This article reports the demographic composition of the U.S. and compares those data with the professional healthcare workforce. With a non-White population of nearly 25%, only 10% of RNs are non-White and about 12% of medical students are non-White. Four reasons are presented for increasing diversity among healthcare professionals. These four include: improved culturally competent care, access to healthcare, healthcare outcomes and research, and provider access in high-need service areas. Healthcare organizations have gone on record as supporting increased diversity within high-skilled healthcare professions but without a commitment to increasing enrollments in professional healthcare programs, diversity goals will never be reached.

Micromultiplane transesophageal echocardiographic probe for intraoperative study of congenital heart disease repair in neonates, infants, children, and adults

This study reports the development of a micromultiplane 8.2-mm transesophageal echocardiographic probe. The probe is applicable to newborn infants and can deliver diagnostic images in adults.

Trends in multiculturalism in health care

Materiel managers are faced with a shrinking world and changing work environment. The needs and expectations of the customer have shifted because of the increasing number of multicultural groups. These groups will continue to assert their right to culturally sensitive care. Materiel managers also need to learn to support and enhance the skills of a multicultural work force. One important tool for change will be technology. However, technology that brings the world closer together also creates new challenges for managers, who will have to deal with multicultural colleagues, buyers, sellers, and manufacturers of goods and services.

Concept analysis: cultural competence

To evaluate theory, concepts with that theory must be identified, analyzed and defined. The aim of this concept analysis of cultural competence is to clarify and differentiate the term as it is used in health care and nursing literature and to separate cultural competence from its measurement. Before the question of what is cultural competence can be answered, culture and competence--as separate terms--must be understood. Components of the cultural competence concept are identified along with its antecedents and consequences. Additionally, terms closely related to cultural competence are described and differentiated from the cultural competence concept. To add meaning to the analysis, a cultural competence model case and contrary case are supplied along with outcome measures and empirical referents for cultural competence. Finally, a concluding definition based on extensive review of literature sources such as archeology, anthropology, history, psychology, policy, criminal justice, occupational therapy, medicine, nursing, and education is provided.

Usefulness of transesophageal imaging of flow convergence region in the operating room for evaluating isolated patent ductus arteriosus

Transesophageal echocardiography (TEE) was performed in 21 patients with isolated patent ductus arteriosus (PDA) with a color Doppler flow convergence method during surgical closure of the ductus. Evaluation of PDA by TEE with the flow convergence method may provide valuable information during surgery and/or thorascopic ductus clipping.

New Russian immigrants: health problems, practices, and values

As with many ethnic immigrant groups, the Russian immigrants have experienced drastic cultural shock. Even thought there has been tremendous increases in the number of Russians relocating to the United States of America (U.S.A.), very little health care-related information is available about Russian immigrants. This article explores Russian immigrants' themes of potential stress, health problems, and self-care/self-help strategies as reported by a focus group of Russian immigrants in a large U.S.A. southern metropolitan city.

Phase II trial of irinotecan in patients with progressive or rapidly recurrent colorectal cancer

PURPOSE

To evaluate irinotecan (CPT-11; Yakult Honsha, Tokyo, Japan) in patients with metastatic colorectal carcinoma that had recurred or progressed following fluorouracil (5-FU)-based therapy.

PATIENTS AND METHODS

Patients were treated with irinotecan 125 to 150 mg/m2 intravenously (IV) every week for 4 weeks, followed by a 2-week rest. Forty-eight patients were entered onto the study and all were assessable for toxicity. Forty-three patients completed one full course of therapy and were assessable for response.

RESULTS

One complete and nine partial responses were observed (response rate, 23%; 95% confidence interval [CI], 10% to 36%). The median response duration was 6 months (range, 2 to 13). The median survival time was 10.4 months and the 1-year survival rate was 46% (95% CI, 39% to 53%). Grade 4 diarrhea occurred in four of the first nine patients (44%) treated on this study at the 150-mg/m2 dose level. The study was amended to reduce the starting dose of irinotecan to 125 mg/m2. At this dose, nine of 39 patients (23%) developed grade 4 diarrhea. Aggressive administration of loperamide also reduced the incidence of grade 4 diarrhea. Grade 4 neutropenia occurred in eight of 48 patients (17%), but was associated with bacteremia and sepsis in only case.

CONCLUSION

Irinotecan has significant single-agent activity against colorectal cancer that has progressed during or shortly after treatment with 5-FU-based chemotherapy. The incidence of severe diarrhea is reduced by using a starting dose of irinotecan 125 mg/m2 and by initiating loperamide at the earliest signs of diarrhea. These results warrant further clinical evaluation to define the role of irinotecan in the treatment of individuals with colorectal cancer.

A phase I and pharmacokinetics study of 2-chlorodeoxyadenosine in patients with solid tumors

Preclinical studies of 2-chlorodeoxyadenosine (2-CdA) against solid tumors in the human tumor cloning assay and evidence that 2-CdA is active against slow-growing or resting tumor cells have stimulated interest in the clinical activity of this agent against solid tumors. This study sought to estimate the maximum tolerated dose, dose-limiting toxicity, and plasma and urine pharmacokinetics accompanying the intravenous administration of 2-CdA by 120-h continuous infusion in patients with solid tumors. Treated patients were also assessed for other toxicities of therapy and for antitumor response. A total of 23 patients received 35 courses of treatment given at doses of 3.5, 5.3, 6.5 and 8.1 mg/m2 per day by continuous intravenous infusion for 5 days and repeated every 28 days. Blood and urine specimens were collected before, during, and after drug infusion. The dose-limiting toxicity at 8.1 mg/m2 per day manifested as granulocytopenia in 2 of 5 patients (3 of 7 courses of treatment) and as thrombocytopenia in 3 of 5 patients (3 of 7 courses of treatment). At the dose levels of 6.5 and 8.1 mg/m2 per day, recovery from thrombocytopenia was often delayed. Severe lymphocytopenia (< 1,000/microliters) was observed at all dose levels of 2-CdA. Dose-related anemia and leukopenia were observed and were infrequently severe. Non-hematological toxicities were confined to mild-to-moderate nausea, vomiting, fatigue, and anorexia. Fever of 37 degrees-40 degrees C was induced during drug infusion in 19 patients. No antitumor response was observed. Average plasma concentrations at steady-state (Cpss) ranged from 3 ng/ml at the initial dose level to 13 ng/ml at the dose level of 8.1 mg/m2 per day. Both the Cpss and the area under the plasma concentration-time curve (AUC) were proportional to the dose. A relationship was observed between the percentage of change in absolute neutrophil count and the AUC. Renal excretion accounted for only 18% of the elimination of 2-CdA over the 5-day infusion period. The maximum tolerated dose for 2-CdA given by 5-day continuous infusion was 8.1 mg/m2 per day in this study. The recommended dose on this schedule for phase II studies is 6.5 mg/m2 per day. Granulocytopenia and thrombocytopenia were dose-limiting. No antitumor activity was observed during this study. On the basis of the plasma concentrations of 2-CdA observed, it is unlikely that this schedule of drug administration will permit achievement of the concentrations consistent with antitumor activity observed in preclinical studies.

An in vitro model for the effects of androgen on neurons employing androgen receptor-transfected PC12 cells

Androgen alters neurite outgrowth, synaptic organization, and cell survival in various portions of the brain and spinal cord. However, examination of the specific effects of androgen on neurons in vivo has been difficult. Previously, an in vitro model for the effects of estrogen on neurons was developed and characterized, using an estrogen receptor (ER)-transfected PC12 rat pheochromocytoma cell line. This model demonstrated estrogenic regulation of neurite outgrowth, spine formation, and gap junction formation. Similarly, an in vitro model for the effects of androgen on neurons is now described. Wild-type cells (PC12-WT) were stably transfected with an expression vector coding for the full-length cDNA for the human androgen receptor (AR). Resultant clones were isolated, screened for incorporation of vector and expression of AR mRNA and protein, and analyzed for morphologic responses to androgen. PC12-WT, NE09 (ER-negative, AR-negative), SER8 (ER-positive, AR-negative), and AR8 (ER-negative, AR-positive) cells were exposed to 10 ng/ml nerve growth factor (NGF), along with 0-10(-7) M dihydrotestosterone (DHT) for 2 days. AR8 cells demonstrated an androgen dose-dependent increase in mean neurite length, branch order, and neurite field area, whereas neurite branch segment length and soma area were not affected by androgen. PC12-WT, NE09, and SER8 cells exhibited no alterations in cell morphology with DHT exposure. Because of the synergistic effects of DHT and NGF, the regulation of NGF receptor mRNA by DHT was evaluated; however, no significant induction of either trkA or p75 mRNA expression by androgen was documented. The results suggest that in AR-positive PC12 cells, androgen acts additively with NGF to increase neurite outgrowth; but androgen effects are mediated specifically through branching and arborization. These responses are similar to developmental studies of androgen effects in vivo. Thus, androgen appears to induce an inherent neural morphologic program in AR-containing cells, which increases the receptive field of these cells, increasing the likelihood for interneural communication, although not promoting communication itself. These cell lines will provide a unique in vitro system for studying mechanisms of androgen-neuron interactions.

Analysis of astrovirus serotype 1 RNA, identification of the viral RNA-dependent RNA polymerase motif, and expression of a viral structural protein

We report the results from sequence analysis and expression studies of the gastroenteritis agent astrovirus serotype 1. We have cloned and sequenced 5,944 nucleotides (nt) of the estimated 7.2-kb RNA genome and have identified three open reading frames (ORFs). ORF-3, at the 3' end, is 2,361 nt in length and is fully encoded in both the genomic and subgenomic viral RNAs. Expression of ORF-3 in vitro yields an 87-kDa protein that is immunoprecipitated with a monoclonal antibody specific for viral capsids. This protein comigrates with an authentic 87-kDa astrovirus protein immunoprecipitated from infected cells, indicating that this region encodes a viral structural protein. The adjacent upstream ORF (ORF-2) is 1,557 nt in length and contains a viral RNA-dependent RNA polymerase motif. The viral RNA-dependent RNA polymerase motifs from four astrovirus serotypes are compared. Partial sequence (2,018 nt) of the most 5' ORF (ORF-1) reveals a 3C-like serine protease motif. The ORF-1 sequence is incomplete. These results indicate that the astrovirus genome is organized with nonstructural proteins encoded at the 5' end and structural proteins at the 3' end. ORF-2 has no start methionine and is in the -1 frame compared with ORF-1. We present sequence evidence for a ribosomal frameshift mechanism for expression of the viral polymerase.

A randomized phase I trial of chronic oral etoposide with or without granulocyte-macrophage colony-stimulating factor in patients with advanced malignancies

Data from an in vitro human tumor-cloning assay suggested synergistic cytotoxicity when etoposide (VP16) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were combined. To explore this potential, we undertook a prospectively randomized three-arm trial in a phase I setting with various schedules of VP16 and GM-CSF. Thirty-one patients were enrolled in the three-arm trial. Arm A consisted of oral VP16 daily for up to 21 days with cycles repeated every 35 days. Arm B included oral VP16 daily for up to 21 days plus concomitant GM-CSF at 5 micrograms/kg/day s.c. days 1-10. Arm C included oral VP16 daily for up to 21 days plus pretreatment with GM-CSF at the same dose for 5 days (days -6 to -2). VP16 was begun at 25 mg/m2/day on level 1 and increased to 50 mg/m2/day on level 2. Twenty-seven patients were evaluable for toxicity, nine on each arm (six patients on each arm on level 1, three patients on each arm on level 2). Neutropenia on arm B (concomitant VP16 and GM-CSF) was earlier and more profound than on arm A or C. The median absolute neutrophil count and day of nadir for arms A, B, and C were 3295, 988, and 1600/mm3 and days 23, 15, and 26, respectively. Thrombocytopenia was generally uncommon except on arm C level 2, where the median platelet count was 26,000/mm3. One partial response (arm B) in a patient with non-small cell lung cancer was seen. Dose intensity favored arm A. Neither concomitant therapy with VP16 and GM-CSF (arm B) nor pretreatment with GM-CSF (arm C) improved dose intensity over VP16 alone (arm A), and arms B and C were complicated by increased neutropenia and thrombocytopenia.

Phase I and pharmacokinetic trial of weekly CPT-11

PURPOSE

We conducted a phase I and pharmacokinetic trial of CPT-11 (irinotecan) to characterize the maximum-tolerated dose (MTD), toxicities, pharmacokinetic profile, and antitumor effects in patients with refractory solid malignancies.

PATIENTS AND METHODS

We treated 32 patients with CPT-11 administered as a 90-minute intravenous infusion every week for 4 consecutive weeks followed by a 2-week rest period. Dose levels ranged from 50 to 180 mg/m2/wk. We determined concentrations of the lactone (active) and total (lactone plus carboxylate) forms of CPT-11 and its metabolite, SN-38, in the plasma and urine of selected patients during and after drug infusion.

RESULTS

Grade 4 diarrhea was the dose-limiting toxicity (DLT) at the 180-mg/m2/wk dose level. Other toxicities attributed to CPT-11 included dehydration, nausea, vomiting, and asthenia. Hematologic toxicity was mild in most patients. The terminal plasma half-life for CPT-11 (total) was 7.9 +/- 2.8 hours, for CPT-11 (lactone) 6.3 +/- 2.2 hours, for SN-38 (total) 13.0 +/- 5.8 hours, and for SN-38 (lactone) 11.5 +/- 3.8 hours. We observed significant correlations between drug dose and peak plasma concentration (Cpmax) and between drug dose and area under the concentration curve (AUC) for CPT-11, but not for SN-38.

CONCLUSION

The MTD for CPT-11 in this patient population was 150 mg/m2/wk when administered on a weekly-times-four schedule repeated every 6 weeks. At dose levels greater than 150 mg/m2/wk, diarrhea is dose-limiting.

Cloning and characterization of human astrovirus immunoreactive epitopes

We report the cloning of antigenic, protein-coding regions of human astrovirus serotype 1 that appear to be common to most, if not all, serotypes of human astrovirus. Screening of lambda gt11 libraries identified three different but overlapping clones (A43, A35, and A1) and one independent clone (A14) that reacted with serum from a rabbit repeatedly immunized with purified astrovirus particles but not with its preimmunization serum. These clones were shown to be astrovirus specific. Of note, a radiolabeled probe representing the immunoreactive clones A43-A35-A1 hybridized exclusively to the 7.2-kb astrovirus genomic RNA, while a clone A14-specific probe hybridized with both the genomic and the 2.8-kb astrovirus subgenomic RNAs. This suggests that the immunoreactive epitopes, selected by antiserum to purified astrovirus particles, are encoded by the subgenomic RNA as well as other regions of the genomic RNA.

Polydactyly of the foot in adults: literature review and unusual case presentation with diagnostic and treatment recommendations

The authors present an unusual case of polydactyly of the foot in an otherwise healthy adult male. The modern literature describing polydactyly of the foot is reviewed, as well as a review and critique of various classification schemes for foot polydactyly deformities. The authors applied the classification criteria of Blauth and Olason to an atypical case and to other varied, yet typical, presentations of polydactyly of the foot in adults. Nonsurgical and surgical treatment options are reviewed, and a rational treatment plan is proposed based upon use of the classification scheme. They then apply the management plan for symptomatic polydactyly of the foot to the unusual case, and make recommendations for surgical management of this deformity.

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