Entry inhibitors as arenavirus antivirals

Arenaviruses belonging to the Arenaviridae family, genus mammarenavirus, are enveloped, single-stranded RNA viruses primarily found in rodent species, that cause severe hemorrhagic fever in humans. With high mortality rates and limited treatment options, the search for effective antivirals is imperative. Current treatments, notably ribavirin and other nucleoside inhibitors, are only partially effective and have significant side effects. The high lethality and lack of treatment, coupled with the absence of vaccines for all but Junín virus, has led to the classification of these viruses as Category A pathogens by the Centers for Disease Control (CDC). This review focuses on entry inhibitors as potential therapeutics against mammarenaviruses, which include both New World and Old World arenaviruses. Various entry inhibition strategies, including small molecule inhibitors and neutralizing antibodies, have been explored through high throughput screening, genome-wide studies, and drug repurposing. Notable progress has been made in identifying molecules that target receptor binding, internalization, or fusion steps. Despite promising preclinical results, the translation of entry inhibitors to approved human therapeutics has faced challenges. Many have only been tested in in vitro or animal models, and a number of candidates showed efficacy only against specific arenaviruses, limiting their broader applicability. The widespread existence of arenaviruses in various rodent species and their potential for their zoonotic transmission also underscores the need for rapid development and deployment of successful pan-arenavirus therapeutics. The diverse pool of candidate molecules in the pipeline provides hope for the eventual discovery of a broadly effective arenavirus antiviral.

Multi-Ancestry Polygenic Risk Score for Coronary Heart Disease Based on an Ancestrally Diverse Genome-Wide Association Study and Population-Specific Optimization

BACKGROUND

Predictive performance of polygenic risk scores (PRS) varies across populations. To facilitate equitable clinical use, we developed PRS for coronary heart disease (CHD; PRSCHD) for 5 genetic ancestry groups.

METHODS

We derived ancestry-specific and multi-ancestry PRSCHD based on pruning and thresholding and continuous shrinkage priors (polygenic risk score for CHD developed using ancestry-based continuous shrinkage methods) applied to summary statistics from the largest multi-ancestry genome-wide association study meta-analysis for CHD to date, including 1.1 million participants from 5 major genetic ancestry groups. Following training and optimization in the Million Veteran Program, we evaluated the best-performing PRSCHD in 176 988 individuals across 9 diverse cohorts.

RESULTS

Multi-ancestry polygenic risk score for CHD developed using pruning and thresholding methods and polygenic risk score for CHD developed using ancestry-based continuous shrinkage methods outperformed ancestry-specific Polygenic risk score for CHD developed using pruning and thresholding methods and polygenic risk score for CHD developed using ancestry-based continuous shrinkage methods across a range of tuning values. Two best-performing multi-ancestry PRSCHD (ie, polygenic risk score for CHD developed using pruning and thresholding methods optimized using a multi-ancestry population and polygenic risk score for CHD developed using ancestry-based continuous shrinkage methods optimized using a multi-ancestry population) and 1 ancestry-specific (PRSCSxEUR) were taken forward for validation. Polygenic risk score for CHD developed using pruning and thresholding methods (PT) optimized using a multi-ancestry population demonstrated the strongest association with CHD in individuals of South Asian genetic ancestry and European genetic ancestry (odds ratio per 1 SD [95% CI, 2.75 [2.41-3.14], 1.65 [1.59-1.72]), followed by East Asian genetic ancestry (1.56 [1.50-1.61]), Hispanic/Latino genetic ancestry (1.38 [1.24-1.54]), and African genetic ancestry (1.16 [1.11-1.21]). Polygenic risk score for CHD developed using ancestry-based continuous shrinkage methods optimized using a multi-ancestry population showed the strongest associations in South Asian genetic ancestry (2.67 [2.38-3.00]) and European genetic ancestry (1.65 [1.59-1.71]), lower in East Asian genetic ancestry (1.59 [1.54-1.64]), Hispanic/Latino genetic ancestry (1.51 [1.35-1.69]), and the lowest in African genetic ancestry (1.20 [1.15-1.26]).

CONCLUSIONS

The use of summary statistics from a large multi-ancestry genome-wide meta-analysis improved the performance of PRSCHD in most ancestry groups compared with single-ancestry methods. Despite the use of one of the largest and most diverse sets of training and validation cohorts to date, improvement of predictive performance was limited in African genetic ancestry. This highlights the need for larger Genome-wide association study datasets of underrepresented populations to enhance the performance of PRSCHD.

HIV-1 replication requires optimal activation of the unfolded protein response

Several human diseases including viral infections activate the unfolded protein response (UPR) due to abnormal accumulation of unfolded/misfolded proteins. However, UPR modulation and its functional relevance in HIV-1 infection lack comprehensive elucidation. This study reveals that HIV-1 activates IRE1, PERK, and ATF6 signaling pathways of UPR. The knockdown of PERK and ATF6 reduces HIV-1 long terminal repeat (LTR)-driven gene expression, whereas the endoplasmic reticulum (ER) chaperone HSPA5 prevents proteasomal degradation of HIV-1 p24 through its chaperone activity. Interestingly, overstimulation of UPR by a chemical inducer leads to anti-HIV activity through an enhanced type-1 interferon response. Also, treatment with a chemical ER stress inhibitor reduces HIV-1 replication. These findings suggest that an optimal UPR activation is crucial for effective viral replication, as either overstimulating UPR or inhibiting ER stress leads to viral suppression.

Identification of 5' upstream sequence involved in HSPBP1 gene transcription and its downregulation during HIV-1 infection

The Human Immunodeficiency Virus-1 (HIV-1) is known to modulate the host environment for successful replication and propagation like other viruses. The virus utilises its proteins to interact with or modulate host factors and host signalling pathways that may otherwise restrict the virus. A previous study from our lab has shown that the host heat shock protein 70 (HSP70) binding protein (HSPBP1) is a co-chaperone that inhibits viral replication. We have also shown that the virus downregulates HSPBP1 during infection. However, the mechanism of downregulation remains to be elucidated. In the present study, we hypothesized that the HSPBP1 promoter may be repressed during infection leading to its downmodulation at the RNA and protein levels. The 5' upstream region of the HSPBP1 gene was first mapped and it was identified that a fragment comprising of a ∼600 bp upstream region of the transcription start site show the highest promoter-like activity. Further, the Sp1 transcription factor was shown to be essential for normal promoter activation. Our results further demonstrate that HIV-1 downregulates the activity of the identified promoter. It was seen that the viral transactivator protein, Tat, was responsible for the downmodulation of the HSPBP1 promoter. HIV-1 Tat is known to bind and regulate several cellular promoters during infection, thereby making the environment conducive for establishment of the virus. Our results further show that Tat is recruited to the HSPBP1 promoter and in the presence of Tat, recruitment of Sp1 on HSPBP1 promoter was decreased, which explains the suppression of HSPBP1 during HIV-1 infection. Therefore, this study further adds to the list of cellular promoters that are modulated by Tat during HIV-1 infection either directly or indirectly.

Diversity in heat shock protein families: functional implications in virus infection with a comprehensive insight of their role in the HIV-1 life cycle

Heat shock proteins (HSPs) are a group of cellular proteins that are induced during stress conditions such as heat stress, cold shock, UV irradiation and even pathogenic insult. They are classified into families based on molecular size like HSP27, 40, 70 and 90 etc, and many of them act as cellular chaperones that regulate protein folding and determine the fate of mis-folded or unfolded proteins. Studies have also shown multiple other functions of these proteins such as in cell signalling, transcription and immune response. Deregulation of these proteins leads to devastating consequences, such as cancer, Alzheimer's disease and other life threatening diseases suggesting their potential importance in life processes. HSPs exist in multiple isoforms, and their biochemical and functional characterization still remains a subject of active investigation. In case of viral infections, several HSP isoforms have been documented to play important roles with few showing pro-viral activity whereas others seem to have an anti-viral role. Earlier studies have demonstrated that HSP40 plays a pro-viral role whereas HSP70 inhibits HIV-1 replication; however, clear isoform-specific functional roles remain to be established. A detailed functional characterization of all the HSP isoforms will uncover their role in cellular homeostasis and also may highlight some of them as potential targets for therapeutic strategies against various viral infections. In this review, we have tried to comprehend the details about cellular HSPs and their isoforms, their role in cellular physiology and their isoform-specific functions in case of virus infection with a specific focus on HIV-1 biology.

Comparative analysis of differential gene expression of HSP40 and HSP70 family isoforms during heat stress and HIV-1 infection in T-cells

Heat shock proteins (HSPs) are a family of cellular proteins involved in a variety of biological functions including chaperone activity. HSPs are classified based on their molecular weight and each family has several isoforms in eukaryotes. HSP40 is the most diverse family acting as a co-chaperone for the highly conserved HSP70 family. Some of the isoforms are reported to be induced during heat stress. Few studies have also highlighted the diverse role of some isoforms in different stress conditions including viral infections. But till date, no study has comprehensively examined the expression profile of different HSP40 and 70 isoforms in either heat stress or HIV-1 infection, a virus that is responsible for the pandemic of AIDS. In the present study, we have compared the mRNA expression profile of HSP40 and HSP70 isoforms during heat stress and HIV-1 infection in a T-cell line and also validated the HIV-1 stress results in peripheral blood mononuclear cells. In case of HSP70, we observed that three isoforms (HSPA1A, HSPA1B, and HSPA6) are highly upregulated during heat stress, but these isoforms were found to be downregulated during the peak of HIV-1 infection. While in case of HSP40, we found that only DNAJA4, DNAJB1, and DNAJB4 showed significant upregulation during heat stress, whereas in HIV-1 infection, majority of the isoforms were induced significantly. Stress-dependent differential expression observed here indicates that different HSP40 and HSP70 isoforms may have specific roles during HIV-1 infection and thus could be important for future studies.

Multiphase CT Angiography: A Useful Technique in Acute Stroke Imaging-Collaterals and Beyond

Multiphase CTA offers several important advantages over the traditional single-phase CTA technique in acute ischemic stroke, including improved detection of large-vessel occlusion, improved characterization of collateral status, improved tolerance of patient motion and poor hemodynamics, and higher interrater reliability. These benefits are gleaned at little additional cost in terms of time, risk to the patient, and capital expense. Existing data suggest that there are important benefits to using multiphase CTA in lieu of single-phase CTA in the initial vessel assessment of patients with acute stroke.

Genomic integrity of human induced pluripotent stem cells across nine studies in the NHLBI NextGen program

Human induced pluripotent stem cell (hiPSC) lines have previously been generated through the NHLBI sponsored NextGen program at nine individual study sites. Here, we examined the structural integrity of 506 hiPSC lines as determined by copy number variations (CNVs). We observed that 149 hiPSC lines acquired 258 CNVs relative to donor DNA. We identified six recurrent regions of CNVs on chromosomes 1, 2, 3, 16 and 20 that overlapped with cancer associated genes. Furthermore, the genes mapping to regions of acquired CNVs show an enrichment in cancer related biological processes (IL6 production) and signaling cascades (JNK cascade & NFκB cascade). The genomic region of instability on chr20 (chr20q11.2) includes transcriptomic signatures for cancer associated genes such as ID1, BCL2L1, TPX2, PDRG1 and HCK. Of these HCK shows statistically significant differential expression between carrier and non-carrier hiPSC lines. Overall, while a low level of genomic instability was observed in the NextGen generated hiPSC lines, the observation of structural instability in regions with known cancer associated genes substantiates the importance of systematic evaluation of genetic variations in hiPSCs before using them as disease/research models.

An EEG coherence-based analysis approach for investigating response conflict processes in 7 and 9-year old children

Understanding the development of the brain's neural networks can reveal critical insights into the cognitive changes that occur from infancy to late childhood. Behavioural metrics including: task accuracy, stimuli recognition, and reaction time show dramatic changes over childhood. In this study we investigated response control using the Erikson Flanker task. In a dataset of 45 EEG recordings, we calculated spectral coherence to measure connectivity between all possible electrode pairs. Coherence measures were performed on two different trial conditions -congruent (where there is no response conflict) and incongruent (where response conflict is induced). The increase in incongruent coherence compared to the congruent was investigated for each electrode pair over 45 healthy subjects aged seven years. The same calculation was then performed on the same group of subjects two years later when they were aged nine years. The results revealed that at age seven years, increased coherence was detected in the left prefrontal to right and left parieto-occipital - i.e. an anatomical region located between the parietal and occipital lobes - within theta band. No increase was found for the older group-at age nine years- which may indicate cognitive development in conflict processing mechanism.

Targeted deep sequencing of the PEAR1 locus for platelet aggregation in European and African American families

Coronary artery disease (CAD) remains a major cause of mortality and morbidity worldwide. The aggregation of activated platelets on a ruptured atherosclerotic plaque is a critical step in most acute cardiovascular events like myocardial infarction. Platelet aggregation both at baseline and after aspirin is highly heritable. Genome-wide association studies (GWAS) have identified a common variant within the first intron of the platelet endothelial aggregation receptor1 (PEAR1), to be robustly associated with platelet aggregation. In this study, we used targeted deep sequencing to fine-map the prior GWAS peak and identify additional rare variants of PEAR1 that account for missing heritability in platelet aggregation within the GeneSTAR families. In this study, 1709 subjects (1043 European Americans, EA and 666 African Americans, AA) from families in the GeneSTAR study were included. In vitro platelet aggregation in response to collagen, ADP and epinephrine was measured at baseline and 14 days after aspirin therapy (81 mg/day). Targeted deep sequencing of PEAR1 in addition to 2kb of upstream and downstream of the gene was performed. Under an additive genetic model, the association of single variants of PEAR1 with platelet aggregation phenotypes were examined. Additionally, we examined the association between the burden of PEAR1 rare non-synonymous variants and platelet aggregation phenotypes. Of 532 variants identified through sequencing, the intron 1 variant, rs12041331, was significantly associated with all platelet aggregation phenotypes at baseline and after platelet inhibition with aspirin therapy. rs12566888, which is in linkage disequilibrium with rs12041331, was associated with platelet aggregation phenotypes but to a lesser extent. In the EA families, the burden of PEAR1 missense variants was associated with platelet aggregation after aspirin therapy when the platelets were stimulated with epinephrine (p = 0.0009) and collagen (p = 0.03). In AAs, the burden of PEAR1 missense variants was associated, to a lesser degree, with platelet aggregation in response to epinephrine (p = 0.02) and ADP (p = 0.04). Our study confirmed that the GWAS-identified variant, rs12041331, is the strongest variant associated with platelet aggregation both at baseline and after aspirin therapy in our GeneSTAR families in both races. We identified additional association of rare missense variants in PEAR1 with platelet aggregation following aspirin therapy. However, we observed a racial difference in the contribution of these rare variants to the platelet aggregation, most likely due to higher residual missing heritability of platelet aggregation after accounting for rs12041331 in the EAs compared to AAs.

Response conflict processes' classification in 7 and 9 year old children using EEG brain connectivity measures

Investigating cognitive development of children poses interesting challenges pertaining to emergence of children's' ability to think and understand. Psychological tasks that involve conflict, like the Flanker task, are widely used to understand development of response conflict processes. In this study, EEG signals were used to examine the coherence and imaginary part of coherency within the delta, theta, alpha and beta bands across different conditions of the Flanker task. Longitudinal data were collected from a group of typically developing children at ages of seven and nine. We found that the imaginary part of coherency was more helpful in distinguishing between stimuli - alpha and beta bands resulted in 90.90% classification rate in seven year old children. The beta and theta bands were found to be more effective for stimuli classification in nine year old children - more than 84.09% classification accuracy was achieved.

Notch1 endocytosis is induced by ligand and is required for signal transduction

The Notch signalling pathway is widely utilised during embryogenesis in situations where cell-cell interactions are important for cell fate specification and differentiation. DSL ligand endocytosis into the ligand-expressing cell is an important aspect of Notch signalling because it is thought to supply the force needed to separate the Notch heterodimer to initiate signal transduction. A functional role for receptor endocytosis during Notch signal transduction is more controversial. Here we have used live-cell imaging to examine trafficking of the Notch1 receptor in response to ligand binding. Contact with cells expressing ligands induced internalisation and intracellular trafficking of Notch1. Notch1 endocytosis was accompanied by transendocytosis of ligand into the Notch1-expressing signal-receiving cell. Ligand caused Notch1 endocytosis into SARA-positive endosomes in a manner dependent on clathrin and dynamin function. Moreover, inhibition of endocytosis in the receptor-expressing cell impaired ligand-induced Notch1 signalling. Our findings resolve conflicting observations from mammalian and Drosophila studies by demonstrating that ligand-dependent activation of Notch1 signalling requires receptor endocytosis. Endocytosis of Notch1 may provide a force on the ligand:receptor complex that is important for potent signal transduction.

Intestinal transplant registry report: global activity and trends

The Registry has gathered information on intestine transplantation (IT) since 1985. During this time, individual centers have reported progress but small case volumes potentially limit the generalizability of this information. The present study was undertaken to examine recent global IT activity. Activity was assessed with descriptive statistics, Kaplan-Meier survival curves and a multiple variable analysis. Eighty-two programs reported 2887 transplants in 2699 patients. Regional practices and outcomes are now similar worldwide. Current actuarial patient survival rates are 76%, 56% and 43% at 1, 5 and 10 years, respectively. Rates of graft loss beyond 1 year have not improved. Grafts that included a colon segment had better function. Waiting at home for IT, the use of induction immune-suppression therapy, inclusion of a liver component and maintenance therapy with rapamycin were associated with better graft survival. Outcomes of IT have modestly improved over the past decade. Case volumes have recently declined. Identifying the root reasons for late graft loss is difficult due to the low case volumes at most centers. The high participation rate in the Registry provides unique opportunities to study these issues.

Notch4 reveals a novel mechanism regulating Notch signal transduction

Notch4 is a divergent member of the Notch family of receptors that is primarily expressed in the vasculature. Its expression implies an important role for Notch4 in the vasculature; however, mice homozygous for the Notch4(d1) knockout allele are viable. Since little is known about the role of Notch4 in the vasculature and how it functions, we further investigated Notch4 in mice and in cultured cells. We found that the Notch4(d1) allele is not null as it expresses a truncated transcript encoding most of the NOTCH4 extracellular domain. In cultured cells, NOTCH4 did not signal in response to ligand. Moreover, NOTCH4 inhibited signalling from the NOTCH1 receptor. This is the first report of cis-inhibition of signalling by another Notch receptor. The NOTCH4 extracellular domain also inhibits NOTCH1 signalling when expressed in cis, raising the possibility that reported Notch4 phenotypes may not be due to loss of NOTCH4 function. To better address the role of NOTCH4 in vivo, we generated a Notch4 null mouse in which the entire coding region was deleted. Notch4 null mice exhibited slightly delayed vessel growth in the retina, consistent with our novel finding that NOTCH4 protein is expressed in the newly formed vasculature. These findings indicate a role of NOTCH4 in fine-tuning the forming vascular plexus.

Defluoridation techniques implemented by the government of karnataka, india - the current situation

INTRODUCTION

Karnataka is an Indian state which has regions with endemic fluorosis.

OBJECTIVE

To assess the various defluoridation techniques and units implemented by the Government of Karnataka, along with the cost of installation, maintenance and repair, to mitigate the problem of fluorosis.

METHODS

Information regarding the various defluoridation units was obtained from the Panchyath Raj Engineering office before they were visited. Local authorities and residents were interviewed regarding the reasons behind the success or failure of the units.

RESULTS

Of the 100 reverse osmosis units installed, 77% are defunct, only one of the two state-of-the-art solar-based technique units is currently functioning but none of the activated alumina or Nalgonda technique units.

CONCLUSION

Defluoridation units suitable for Indian conditions and operation by unskilled villagers have yet to be developed.

Evaluation of cranial capacity by mustard seed technique

The volume of the cranium is used as a rough indicator of the size of the brain. In the present study Breitinger's mustard seeds technique was applied for the measurement of cranial capacity. Grossly normal 75 male skulls of Gujarat population were studied at Kesar SAL Medical College, Ahmedabad (Gujarat) in the year 2010. The mean cranial capacity among the study group was recorded to be 1256 cc with a minimum of 1110 cc and maximum of 1430 cc. The results were compared with the similar studies by different authors from different geographical areas.

Anti-lymphocyte therapy successfully controls late "cholestatic" rejection in pediatric liver transplant recipients

Rejection is independently associated with liver graft loss in children. We report the successful rescue of grafts using ATG+/-OKT3 in late rejection associated with cholestasis. Retrospective chart review was performed after IRB approval. Between 2003 and 2010, 14 pediatric liver transplant recipients received anti-lymphocyte treatment for "cholestatic" rejection. Median age at transplantation was 12.7 yr (range 0.9-23.4), eight were boys, and immunosuppression was tacrolimus based. Median time from transplantation to rejection was five yr (range 1.1-10.5). Median peak total bilirubin was 11.1 mg/dL (range 1.4-18). All showed moderate to severe acute rejection and hepatocellular cholestasis on histology. ATG/OKT3 was started as first-line therapy in six and in the remaining eight as second-line therapy after failure of pulse steroids. Thirteen responded with normalization of aminotransferases and bilirubin, median time 16 wk (range 7-112); one non-adherent recipient has still not achieved normal graft function at last follow-up. Patient survival is 100%, with no re-transplantation and no post-transplant lymphoproliferative disease, median follow-up 2.9 yr (range 1.1-7.2). Cholestasis associated with acute rejection occurring late after liver transplantation may herald steroid resistance. First-line therapy with anti-lymphocyte preparations, prophylactic anti-microbial therapy, and close monitoring allow excellent rates of patient and graft survival.

Cytotoxicity of Ni from Surface-Treated Porous Nitinol (PNT) on Osteoblast Cells

The leaching of nickel from the surface of porous Nitinol (PNT) is mainly dependent on its surface characteristics, which can be controlled by appropriate surface treatments. In this investigation, PNT was subjected to two surface treatments, namely, water-boiling and dry-heating passivations. Phosphate buffer saline (PBS) solutions obtained from cyclic potentiodynamic polarization tests on PNT were employed to assess the cytotoxicity of Ni contained therein on osteoblast cells by Sulforhodamine B (SRB) assay. In addition, similar concentrations of Ni were added exogenously to cell culture media to determine cytotoxic effects on osteoblast cells. The morphologies of the untreated and the surface-treated PNTs were examined using SEM and AFM. Furthermore, growth of human osteoblast cells was observed on the PNT surfaces.

Outcome of combined liver and kidney transplantation in hepatitis C: a single-center long-term follow-up experience

INTRODUCTION

Hepatitis C (HCV) cirrhosis is the prevalent liver disease requiring liver transplantation in the United States. Candidates who also have end-stage renal disease, chronic renal disease stage 4, or prolonged hepatorenal syndrome are considered for combined liver and kidney transplantation (CLKT).

MATERIALS AND METHODS

We performed a retrospective study of HCV(+) and HCV(-) CLKT patients with more than 12 months of follow-up and HCV(+) patients with isolated liver transplant (OLT) to compare the outcomes of various groups.

RESULTS

Since 1988, 2983 OLTs were performed at our institution including 58 CLKTs. Of these, 23 were HCV(+) subjects who were significantly older than HCV(-) CLKT patients. Race, pretransplant dialysis time, renal indication for CLKT, Model for End-stage Liver Disease score, donor age, liver and kidney rejection as well as occurrence of posttransplant hypertension were similar among HCV(+) and HCV(-) CLKT patients. Posttransplant diabetes was observed in 80% of the HCV(+) group and 30% of the HCV(-) group (P = .01). Renal function seemed to be better in HCV(-) when compared with HCV(+) subjects at 5 years (P = .09). Overall patient survival for HCV(+) CLKT, HCV(-) CLKT, and HCV(+) OLT groups at 1, 2, and 5 years were not significantly different (P = .6).

CONCLUSION

HCV positivity should not exclude appropriate candidates for CLKT.

Long-term results of intestinal transplantation for pseudo-obstruction in children

PURPOSE

The aim of this study was to determine long-term results of intestinal transplantation in children with pseudo-obstruction, particularly when stomach and colon are not part of the allograft.

METHODS

The authors conducted a case-record review of all children who underwent transplantation at our center for a primary diagnosis of pseudo-obstruction. Supplementary information was obtained from outpatient charts, computerized database, and telephone survey of parents.

RESULTS

Six small bowel and 3 liver-small bowel transplants were carried out in 8 patients between 1993 and 1999. Median follow-up is 40 months (range, 13 to 73 months). Median age at transplantation was 2.7 years (range, 0.7 to 12.8 years). Median graft survival in this series is 15 months (range, 1 day to 71 months). Stomach and colon were excluded from all allografts. Two children died 5 and 368 days after transplant and 2 graft losses occurred in 1 patient. Two children had lymphoproliferative disease; both are alive with functioning grafts. Five survivors with functioning grafts receive full enteral feedings at home. Four of the 5 have had ileostomies closed, and 3 have normal bowel movements.

CONCLUSIONS

Intestinal transplantation without stomach or colon provides children with chronic intestinal pseudo-obstruction with a good quality of life. The underlying disease poses special challenges in management.

5,6-Dihydropyran-2-ones possessing various sulfonyl functionalities: potent nonpeptidic inhibitors of HIV protease

On the basis of previous SAR findings and molecular modeling studies, a series of compounds were synthesized which possessed various sulfonyl moieties substituted at the 4-position of the C-3 phenyl ring substituent of the dihydropyran-2-one ring system. The sulfonyl substituents were added in an attempt to fill the additional S(3)' pocket and thereby produce increasingly potent inhibitors of the target enzyme. Racemic and enantiomerically resolved varieties of selected compounds were synthesized. All analogues in the study displayed decent binding affinity to HIV protease, and several compounds were shown to possess very good antiviral efficacy and safety margins. X-ray crystallographic structures confirmed that the sulfonamide and sulfonate moieties were filling the S(3)' pocket of the enzyme. However, the additional substituent did not provide improved enzymatic inhibitory or antiviral activity as compared to the resolved unsubstituted aniline. The addition of the sulfonyl moiety substitution does not appear to provide favorable pharamacokinectic parameters. Selected inhibitors were tested for antiviral activity in clinical isolates and exhibited similar antiviral activity against all of the HIV-1 strains tested as they did against the wild-type HIV-1. In addition, the inhibitors exhibited good antiviral efficacies against HIV-1 strains that displayed resistance to the currently marketed protease inhibitors.

Nonpeptidic HIV protease inhibitors: 6-alkyl-5,6-dihydropyran-2-ones possessing a novel and achiral 3-(2-t-butyl-5-methyl-4-sulfamate)phenylthio moiety

Dihydropyran-2-ones possessing a sulfamate moiety at the 4-position of the thiophenyl ring were designed to reach S3' pocket of the HIV protease. Synthetic routes for the preparation of thiotosylates possessing 3-(2-t-butyl-5-methyl-4-sulfamate) phenylthio moiety were established. SAR of various sulfamate analogs including HIV protease binding affinities, antiviral activities and therapeutic indices will be described.

Nonpeptidic HIV protease inhibitors: 6-alkyl-5,6-dihydropyran-2-ones possessing achiral 3-(4-amino/carboxamide-2-t-butyl,5-methylphenyl thio) moiety: antiviral activities and pharmacokinetic properties

Dihydropyran-2-ones possessing amino and carboxamide functionalities on 3-SPh (2-tert-butyl, 5-methyl) ring were synthesized and evaluated for their antiviral activities. Both the enantiomers of inhibitor 15 were synthesized. The in vitro resistance profile, inhibitory activities against cytochrome P450 isozymes and pharmacokinetic properties of inhibitor 15S will be discussed.

The role of phytosterols in the pathogenesis of liver complications of pediatric parenteral nutrition

Long-term parenteral nutrition of infants who have had major gut resections is associated with a high incidence of cholestatic liver disease. Affected infants have high plasma concentrations of phytosterols--compounds that resemble cholesterol but have an alkylated side chain. The phytosterols that accumulate in patients receiving parenteral nutrition are derived from the soya oil and/or soya lecithin used to make the intravenous lipid emulsion. There is a striking association between phytosterolemia and cholestatic liver disease. This has led us to put forward the hypothesis that phytosterols can cause cholestasis in susceptible infants. Experiments using neonatal piglets indicate that phytosterols (given without any of the other components of parenteral nutrition) can indeed reduce bile flow. We suggest that increasing the content of phytosterols in cell membranes may interfere with the function of important transport proteins involved in the secretion of bile. Other factors that might contribute to cholestasis (such as inhibition of cholesterol 7 alpha-hydroxylase) are discussed.

Sequence and analysis of the human ABL gene, the BCR gene, and regions involved in the Philadelphia chromosomal translocation

The complete human BCR gene (152-141 nt) on chromosome 22 and greater than 80% of the human ABL gene (179-512 nt) on chromosome 9 have been sequenced from mapped cosmid and plasmid clones via a shotgun strategy. Because these two chromosomes are translocated with breakpoints within the BCR and ABL genes in Philadelphia chromosome-positive leukemias, knowledge of these sequences also might provide insight into the validity of various theories of chromosomal rearrangements. Comparison of these genes with their cDNA sequences reveal the positions of 23 BCR exons and putative alternative BCR first and second exons, as well as the common ABL exons 2-11, respectively. Additionally, these regions include the alternative ABL first exons 1b and 1a, a new gene 5' to the first ABL exon, and an open reading frame with homology to an EST within the BCR fourth intron. Further analysis reveals an Alu homology of 38.83 and 39.35% for the BCR and ABL genes, respectively, with other repeat elements present to a lesser extent. Four new Philadelphia chromosome translocation breakpoints from chronic myelogenous leukemia patients also were sequenced, and the positions of these and several other previously sequenced breakpoints now have been mapped precisely, although no consistent breakpoint features immediately were apparent. Comparative analysis of genomic sequences encompassing the murine homologues to the human ABL exons 1b and 1a, as well as regions encompassing the ABL exons 2 and 3, reveals that although there is a high degree of homology in their corresponding exons and promoter regions, these two vertebrate species show a striking lack of homology outside these regions.

The complete nucleotide sequences of the SacBII Kan domain of the P1 pAD10-SacBII cloning vector and three cosmid cloning vectors: pTCF, svPHEP, and LAWRIST16

The complete nucleotide sequence of the 16,009-bp SacBII Kan domain of the P1 pAD10-SacBII cloning vector and the sequences of three cosmid cloning vectors, pTCF (7941 bp), svPHEP (9201 bp), and LAWRIST16 (5194 bp) have been determined. A modified diatomaceous earth (Prep-A-Gene)-based procedure, which rapidly yields highly supercoiled double-stranded DNA from recombinant P1 and cosmid clones suitable for generating shotgun libraries, also has been developed. The isolated recombinant DNAs were physically sheared to generate 1- to 2-kb fragments that then were blunt-ended and subcloned into double-stranded pUC-based sequencing vectors. The double-stranded sequencing templates were isolated by an alkaline lysis method and subjected to Taq polymerase catalyzed fluorescent end-labeled primer cycle sequencing. After shotgun sequence assembly, contig gaps were closed and ambiguities were resolved via Sequenase catalyzed fluorescent dye-terminator sequencing.

Endogenous opioids and TSH secretion in azotemic male rats

The role of endogenous opioids in the control of thyroid-stimulating hormone (TSH) secretion in uremic male rats was investigated using the narcotic antagonist naloxone. In order to eliminate the effect of weight loss due to uremia-induced anorexia as a cause of altered TSH secretion in uremia, we also studied a group of normal control animals who were pair-fed with the uremic animals, so that their weights were comparable to that of the uremic animals. Naloxone administration produced a significant increase in the basal concentration of TSH response to TRH (5 micrograms i.v.) was significantly blunted in the uremic animals compared to the normal controls and the starved animals. Naloxone administration did not alter the peak thyrotropin-releasing hormone (TRH) stimulated TSH response in any of the experimental groups of rats. Because of the possibility that the effects of naloxone on TSH secretion in the uremic rats were related to impaired clearance of the naloxone in those animals, an additional group of normal rats was given twice the dose of naloxone administered to the uremic animals. The higher dose of naloxone was similarly without effect on the basal or TRH-stimulated TSH secretion in this group. The data suggest that experimental renal failure is associated with diminished sensitivity of the thyrotroph to TRH stimulation and that this blunted sensitivity cannot be abolished by blockade of endogenous opioids by naloxone. Opioid blockade does, however, increase basal TSH secretion in uremic animals, suggesting an increase in endogenous opioidergic tone in uremia.(ABSTRACT TRUNCATED AT 250 WORDS)

Gonadotropin secretion in azotemic male rats--effect of opioid blockade

The role of endogenous opioids in the control of gonadotropin secretion in uremic male rats was investigated using the narcotic antagonist, naloxone. In order to eliminate the effect of weight loss due to uremia-induced anorexia as a cause of previously described altered gonadotropin secretion in uremia, we also studied a group of normal pair-fed control animals who exhibited a weight loss comparable to that of the uremic animals. Naloxone administration had no effect on the basal or LRH-stimulated peak concentrations of LH and FSH in the normal or the uremic rats. Basal and LRH-stimulated gonadotropin responses in the pair-fed rats were comparable to those seen in the normal rats. Similarly, opioid blockade produced no change in the basal or LRH-stimulated gonadotropin responses in the pair-fed animals. Testosterone concentrations were significantly lower in the uremic and pair-fed animals compared to the normal rats. The data suggest that experimental renal failure is not associated with altered opioidergic tone, as it relates to gonadotropin secretion, or to diminished sensitivity of the gonadotroph to LRH stimulation. The decreased testosterone concentration seen in the uremic and pair-fed rats may reflect abnormalities in gonadal hormone secretion due to primary pathology occurring at the level of the gonad. These abnormalities may be reflected as diminished Leydig cell sensitivity to LH. The inappropriately low concentrations of LH in the presence of low testosterone together with normal gonadotropin response to exogenous LRH also suggest an abnormal secretion of endogenous LRH. It is not clear whether this presumed abnormality in LRH secretion is a primary event or is related to decreased testosterone production by the testes in the uremic and pair-fed rats.

Gamma-aminobutyric acid and dysregulation of TSH secretion in uremic male rats

The role of gamma-aminobutyric acid (GABA) in the abnormal secretion of thyrotropic hormone (TSH) in uremia was studied in male Sprague-Dawley rats rendered renally insufficient by subtotal nephrectomy. Baseline TSH concentrations in normal control animals and in the uremic animals were similar. The peak TSH response to thyrotropin-releasing hormone (TRH; 5 micrograms i.v.) was significantly blunted in the uremic animals compared to the controls. Pretreatment of the uremic animals with the specific GABA antagonist, bicuculline (1.5 mumol i.v.) resulted in normalization of the peak TSH response to TRH. Bicuculline pretreatment, however, did not alter the basal secretion of TSH in either the normal or the uremic animals, and it also did not augment the TRH-stimulated TSH response in the normal animals. Sham-operated animals demonstrated basal and TRH-stimulated TSH responses comparable to the control group. In order to assess whether the weight loss associated with uremia could have accounted for the blunted TRH-stimulated TSH secretion in the uremic animals, a group of rats were starved so that their weights were comparable to those of the uremic animals. Basal and TRH-stimulated TSH responses in this group were not significantly different from the controls. Bicuculline pretreatment of the starved animals also failed to alter the basal and TRH-stimulated TSH responses. These data indicate that an increase in central gabaergic tone may be partly responsible for the blunted TSH response to TRH seen in uremia, but that GABA is not an important modulator of TSH secretion in the normal rat.

Pluripotent steroidogenesis and ultrastructure in adrenocortical adenomas causing Cushing's syndrome

Adrenal vein catheterization data from 2 patients with adrenocortical adenomas causing Cushing's syndrome are presented and the electron-microscopic features of one of the tumors are described. Based on the catheterization data both tumors produced all three classes of adrenal steroids (mineralocorticoids, glucocorticoids and sex steroids). Electron-microscopic examination of the tumor cells suggested an origin from the zona fasciculata. If one accepts the theory of a common cellular origin of adrenal tumors, then the pattern of steroidogenesis would indicate that the postulated original 'stem' cell retains the potential of secreting all classes of adrenocortical steroids. The clinical presentation of such tumors would thus reflect the hypersecretion of one of the steroid classes relative to the others.

Dopamine and TSH secretion in uremic male rats

The role of dopamine in the dysregulation of TSH secretion in uremic male rats was investigated using the dopamine antagonist, pimozide. In order to obviate the effect of weight loss due to uremia-induced anorexia as a cause of altered TSH secretion in uremia, we also studied a group of normal animals whose food intake was restricted and who demonstrated weight loss comparable to that of the uremic animals. Baseline TSH concentrations were not significantly different in the normal, uremic or starved animals. Pimozide administration produced no change in the baseline TSH concentrations in any of the groups of rats. The peak TSH response to TRH (5 micrograms IV) was significantly blunted in the uremic animals compared to the normal controls and the starved animals. Pimozide administration did not alter the peak TRH-stimulated TSH response in either the normal animals or the starved animals. However, the peak TRH-stimulated TSH response was significantly increased in the uremic animals and was comparable to the peak TSH response seen in the pimozide-untreated control animals. The data suggest that experimental renal failure in rats is associated with diminished sensitivity of the thyrotroph to TRH stimulation, and that this blunted sensitivity may be dopamine-dependent since it can be abolished by pharmacologic dopamine blockade.

Interaction between gabaergic and opioid pathways in the regulation of gonadotropin secretion in males

The effects of naloxone infusion given together with an infusion of LRH on gonadotropin secretion, were studied in 6 normal male volunteers before and after pretreatment with the GABA-transaminase inhibitor, valproic acid. In concordance with previous studies, naloxone infusion augmented the LRH-stimulated secretion of LH. Baseline serum LH concentrations were not significantly different after valproic acid pretreatment compared to control values. Similarly, valproic acid pretreatment failed to blunt the naloxone-augmented LRH-stimulated secretion of LH. Our data suggest that the previously reported animal studies on the central suppressive effect of GABA on endogenous LRH release is less prominent than the suppressive effect of opioidergic regulatory mechanisms in the human male.

Beta-endorphin/beta-lipotropin release and gonadotropin secretion after acute exercise in normal males

The plasma beta-endorphin (beta-EP) and beta-lipotropin (beta-LPH) response to acute exercise and the relationship of these opioid peptides to basal and luteinizing hormone-releasing hormone (LRH)-stimulated luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion was studied in eight normal male volunteers. Acute exercise resulted in a rise in plasma beta-LPH levels that returned to base line when measured 60 min after exercise. Plasma beta-EP levels did not demonstrate any rise when measured immediately after 20 min of exercise or at 60 min after exercise. Serum LH concentrations in individual volunteers declined to nadir values 60-180 min after exercise after which they showed a rebound to levels higher than the preexercise values in three of five volunteers in whom nadir LH levels were attained before the final (180 min) measurement. Serum FSH concentrations were unaltered by exercise. Acute exercise similarly did not alter the LH/FSH response to exogenous LRH stimulation. Pretreatment of the volunteers with the narcotic antagonist, naloxone, failed to alter the postexercise or LRH-stimulated LH and FSH release. The data suggest that beta-EP does not exert a suppressive effect on LH secretion after acute exercise in normal human males. Whether the suppression of LH secretion after acute exercise in unconditioned males is due to factor(s) cosecreted with beta-LPH, an increase in brain beta-EP or to alternate mechanisms such as alteration in central dopaminergic or GABAergic tone remains to be established.

Progressive sensory loss in familial dysautonomia

Clinical variability in sensory impairment was demonstrated among 75 patients with familial dysautonomia. Older patients had a greater tendency toward increased dysfunction in pain sensation, joint position and Romberg's sign, and vibratory sense. Significant worsening with increased age was supported by retesting of 53 patients after a five-year interval. Sensory and motor axon loss were indicated by electrodiagnostic testing of peripheral nerves and abnormal cortical somatosensory evoked potentials. Familial dysautonomia is a hereditary disease with variable penetrance which involves both failure of intrauterine development of neurons and their postnatal maintenance.