Growth factor regulation of the molecular chaperone calnexin

Heregulin-beta1 (HRG) is a regulatory polypeptide having several distinct biological effects in mammary epithelial cells. To address the hypothesis that HRG selectively regulates gene expression, we performed differential display screening using cells grown in the presence or absence of HRG. One cDNA clone upregulated by HRG was identical to human calnexin, a protein with molecular chaperone function. This is the first demonstration of the regulation of calnexin mRNA and protein expression by a physiologically relevant polypeptide factor in human breast cancer cells. HRG stimulation also caused a rapid redistribution of calnexin from vesicle-like structures in the cell cytoplasm to the perinuclear area and to the cell membrane. Furthermore, HRG induced colocalization and physical interaction of calnexin with the HER2 growth factor receptor. Finally, calnexin protein levels were increased in progressive stages of human breast cancer. These findings suggest that stimulation of calnexin expression by HRG may constitute a mechanism of protein redistribution and facilitate downstream signaling events in growth-factor-activated cells.

Inhibition of HIV-1 Tat-dependent trans activation by steric block chimeric 2'-O-methyl/LNA oligoribonucleotides

The HIV-1 trans-activation responsive element (TAR) RNA 59-residue stem-loop interacts with the HIV trans-activator protein Tat and other cellular factors to stimulate transcriptional elongation from the viral long terminal repeat (LTR). Inhibition of these interactions blocks full-length HIV transcription and hence replication. We have found that three types of 12-residue oligonucleotide analogues, namely, a 2'-O-methyl oligoribonucleotide (OMe), a chimeric oligonucleotide containing 7xOMe and 5x5-methyl C locked nucleic acid (LNA) residues, and a peptide nucleic acid (PNA), inhibit Tat-dependent in vitro transcription in HeLa cell nuclear extract equally efficiently (50% inhibition at 100-200 nM) and sequence specifically. The results are correlated with surprisingly similar binding strengths to a model 39-residue TAR under transcription conditions. A 12-mer containing 11 contiguous LNA residues was less effective in both Tat-dependent transcription inhibition and TAR 39 binding. Anti-TAR 3'-carboxyfluorescein- (FAM-) labeled OMe and OMe/LNA chimeric 12-mers were also efficient Tat-dependent in vitro transcription inhibitors as were 3'-FAM-labeled OMe oligonucleotides containing some phosphorothioate (PS) linkages. By use of a HeLa cell line containing stably integrated plasmids expressing firefly luciferase under HIV-LTR/Tat dependence as well as a Renilla luciferase constitutive control, we showed submicromolar, selective, dose-dependent, and sequence-dependent intracellular inhibition of Tat-TAR trans activation by the anti-TAR 3'-FAM 12-residue 7xOMe/5xLNA oligonucleotide when delivered by cationic lipid. No intracellular activity was observed for the corresponding anti-TAR 3'-FAM OMe 12-mer. An alternating PS-containing 3'-FAM OMe 12-mer oligonucleotide exhibited partial inhibition of trans-activation activity, but this was correlated with a similar effect on control gene expression, suggesting nonspecific inhibition.

Quantitative structure-activity relationship study on tetrahydro-beta-carboline antagonists of the serotonin 2B (5HT2B) contractile receptor in the rat stomach fundus

The antagonist actions of three sub-series of tetrahydro-beta-carbolines at the serotonin 2B (5HT2B) contractile receptor in the rat stomach fundus are analyzed in relation to the physicochemical properties of the molecules. Significant correlations are obtained between the 5HT2B receptor antagonist affinity and the hydrophobic, steric, electronic, hydrogen bond acceptor and some indicator variables of substituents. Based on these findings, the mode of actions of these congeneric series and future strategy to synthesize more potential compounds are discussed.

Virus enhancement following infection with antibody-coated infectious bursal disease virus (IBDV) in chickens

A novel concept of vaccination, employing virus-antibody complex has been reported for the control of infectious bursal disease in chickens. A comparison of virus replication, serum neutralizing antibody response and pathogenicity in chickens inoculated with the antibody coated virus, prepared by mixing virus and antibody in different ratios (1:1, 1:0.1, 1: 0.01) and virus alone without antibody, has been made. Antibody coated virus (when mixed in certain crucial ratios) replicated to a higher magnitude in the target organ, caused more severe pathogenesis but induced a primary serum neutralizing antibody response almost comparable. The results may have important implications in understanding of pathogenesis and development of control strategies against infectious bursal disease virus, specially employing immune complex vaccine.

Endourologic management of obstetrical ureterouterine fistula: case report and review of literature

A 32-year-old woman presented to us with complaints of paradoxical incontinence for a period of 6 months following a cesarean section for obstructed labor performed elsewhere and subsequently treated elsewhere. Clinical and urographic assessment revealed an iatrogenic ureterouterine fistula, which was successfully treated endoscopically by dilatation of the ureteral stricture and ureteroscopic double-J stenting. It had been explained to the patient, and she had given consent for, ureteroneocystostomy in the event of failure. The literature regarding the management of this rare genitourinary fistula is reviewed and discussed.

Medulloblastomas of the cerebellopontine angle

It is unusual for a medulloblastoma to occur in the cerebellopontine angle (CPA). Four of the total 63 cases of medulloblastoma managed in our department between 1988 to 1998, presented with a mass in the cerebellopontine angle. There were two children amongst these four patients, aged eight and nine years. The other two patients were young adults. Three patients had primary CPA medulloblastoma, while the fourth case had a recurrence in this region, following the excision of the primary vermian tumour. All the four cases were managed by gross total microsurgical excision and craniospinal irradiation. One of the two children, developed subfrontal recurrence after 1 year and 8 months of initial treatment, while the other child developed a large recurrence at primary site, within three months of post-operative irradiation. However, the adult patient developed CPA recurrence and subsequent cervical intramedullary metastasis within two and a half years of diagnosis. These three cases succumbed to their disease, between three months to thirty months of their initial management. However the fourth patient, a 20 years female with desmoplastic variant, was well at two and a half years of follow up.

Animal bite management practices: a survey of health care providers in a community development block of Haryana

It is seen that outcome of animal bites is influenced by various factors including the treatment procedures practiced by health care providers (HCPs). A cross sectional study of health care providers was conducted during May 2000 in PHC Kurali and Naraingarh town of community development block Naraingarh in district Ambala, Haryana. A total of forty-four HCPs were interviewed at their health facility. They were asked about the qualification and number of years in practice. Health care providers were assessed for their knowledge regarding history taking, immediate management of animal bite, post bite anti-rabies treatment, follow up advice and availability of vaccines. Pre-exposure prophylaxis was known to 18.8% of HCPs. Fifty-nine per cent of HCPs were confident in managing dog bites and 93.1% knew about tissue culture vaccine. Vaccine cost was the commonest barrier (38.8%) in the management of animal bites. This study shows a gross difference between awareness and actual practice of management of animal bites.

Characteristics and service use patterns of nonelderly medicare beneficiaries with schizophrenia

OBJECTIVE

The authors sought to describe the characteristics of nonelderly Medicare beneficiaries who have a diagnosis of schizophrenia and to assess the impact of Medicare financing on service quality by comparing service use among individuals who were enrolled only in Medicare and those who were enrolled in both Medicare and Medicaid. The authors hypothesized that persons who received only Medicare benefits would use proportionally fewer psychosocial services and less antipsychotic medication than individuals who were dually enrolled.

METHODS

Data were drawn from the Medicare Current Beneficiary Survey (MCBS). The study sample consisted of 257 individuals younger than age 65 who were included in the 1995 MCBS sample and who had one inpatient or two outpatient claims for schizophrenia between 1992 and 1996. The variables examined were demographic characteristics, comorbid psychiatric and substance use disorders, activities of daily living, instrumental activities of daily living, self-reported use of prescribed antipsychotic medication, and claims for psychosocial services. A multivariate analysis was also conducted to predict the use of antipsychotic medication from demographic and health status variables.

RESULTS

Dually enrolled beneficiaries were significantly more likely to be receiving antipsychotic medication than Medicare-only beneficiaries, even when the analysis controlled for demographic characteristics, health status, and comorbidity. No significant differences were found in the use of psychosocial services.

CONCLUSIONS

The findings were consistent with the hypothesis that Medicare financing, which restricts access to many mental health services, is not conducive to good community care for persons with schizophrenia.

Ab initio studies of the reaction of hydrogen transfer from DNA to the calicheamicinone diradical

BACKGROUND

The biological activity of enediyne chemotherapeutic (anti-cancer) agents is attributed to their ability to cleave duplex DNA. Part of the reaction of cleavage is the abstraction of hydrogens from the deoxyribose moiety of DNA by the biradical formed via a Bergman rearrangement.

METHODS

The mechanism of the reaction of abstraction of two hydrogen atoms from two deoxyribophosphate molecules by the calicheamicinone biradical is studied with ab initio calculations at Hartree-Fock and post-Hartree-Fock level. The Titan program is used to perform the calculations.

RESULTS

It is found that the reactions are exothermic and thus thermodynamically reasonable.

CONCLUSIONS

The mechanism of DNA cleavage by the enediyne-containing drugs is likely to proceed by the abstraction of the hydrogens from deoxyribose by the biradical formed by the drug. Further studies should determine in which way the modification of the drug's structure would make this reaction even more exothermic and, thus, more likely to occur.

Radon exhalation and radiometric prospecting on rocks associated with Cu-U mineralizations in the Singhbhum shear zone, Bihar

The Singhbhum thrust belt is a 200 km long arcuate orogenic belt in Bihar, eastern India. The huge mineral resources, viz. copper, uranium, magnetite, apatite and molybdenite, etc., make it significant from an economic as well as a geological point of view. The belt hosts three types of mineralization: sulphides of copper and other metals, uranium oxides and apatite-magnetite. Several distinct geological episodes are responsible for the evolution of mineralization and the thrust zone itself. Extensive and reliable radiometric prospecting and assaying have been carried out by us for the past 5 years from Dhobani in the east to Turamdih in the west of the Singhbhum shear zone. The present work indicates uranium mineralization in the Pathargora-Rakha area presently being mined for copper and also within areas in the vicinity of Bhatin. Studies on radon emanation have also been undertaken in some parts of the shear zone which indicate reasonably high radon emanation of the soils and rocks studied. This suggests the need for regular monitoring and suitable controls on the mine environment (air quality) and its vicinity. Radon emanation studies coupled with gamma-ray spectrometry and the subsequent modelling of the radiometric and radon measurements will help in the application of radon as a geophysical tracer in exploration of radioactive ore bodies and in radon risk assessment as well as in delineating active and passive faults and even in petroleum exploration.

IEX-1, an immediate early gene, increases the rate of apoptosis in keratinocytes

IEX-1, an immediate early gene, is widely expressed in epithelial and endothelial tissues, and is altered by a variety of growth regulatory factors. We have shown that expression of IEX-1 in keratinocytes increases the growth rate of these cells. The effects of IEX-1 on apoptosis, however, are unclear. To clarify the effects of IEX-1 on apoptosis, we investigated the effects of IEX-1 expression in keratinocytes (HaCaT cells) in the basal state and after the induction of cellular stress. Under normal, non-stressed conditions, both control (HaCaT) and IEX-1-transfected (IEX-HaCaT) cell lines showed no significant differences in the activity of a key apoptotic enzyme, caspase 3 despite significantly higher levels of IEX-1 expression. IEX-HaCaT cells grew faster than HaCaT cells. When both cell lines were irradiated with ultraviolet B radiation, caspase 3 activity increased to a greater extent in the IEX-HaCaT cells than in HaCaT cells. Camptothecin increased caspase 3 activity twice as much in the IEX-HaCaT cells when compared to HaCaT cells. When histone-complex DNA fragments were measured in IEX-HaCaT or HaCaT cells following UVB irradiation or treatment with camptothecin, significantly higher amounts of nucleosomes were seen in the IEX-HaCaT transfected cells. Likewise, serum deprivation induced higher degrees of apoptosis in IEX-HaCaT cells than in HaCaT cells. We conclude that overexpression of IEX-1 in HaCaT keratinocytes increases the growth rate of cells under basal conditions; in the basal state the rate of apoptosis is unchanged. However, the rate of apoptosis increases in IEX-1 overexpressing HaCaT keratinocytes after cells are subjected to stress.

Synthesis and antiviral activity of novel acyclic nucleoside analogues of 5-(1-azido-2-haloethyl)uracils

We present the discovery of a novel category of 5-substituted acyclic pyrimidine nucleosides as potent antiviral agents. A series of 1-[(2-hydroxyethoxy)methyl] (5-7), 1-[(2-hydroxy-1-(hydroxymethyl)ethoxy)methyl] (8-10), and 1-[4-hydroxy-3-(hydroxymethyl)-1-butyl] (11-13) derivatives of 5-(1-azido-2-haloethyl)uracil were synthesized and evaluated for their biological activity in cell culture. 1-[4-Hydroxy-3-(hydroxymethyl)-1-butyl]-5-(1-azido-2-chloroethyl)uracil (12) was the most effective antiviral agent in the in vitro assays against DHBV (EC(50) = 0.31-1.55 microM) and HCMV (EC(50) = 3.1 microM). None of the compounds investigated showed any detectable toxicity to several stationary and proliferating host cells.

A single nucleotide polymorphism in the 3'untranslated region of the CDKN2A gene is common in sporadic primary melanomas but mutations in the CDKN2B, CDKN2C, CDK4 and p53 genes are rare

In this report we present the results of mutational analysis of the CDKN2B, CDKN2C, CDK4, p53 genes and 5'UTR of the CDKN2A gene in a set of 44 sporadic primary melanomas, which had been earlier analysed for mutations in the CDKN2A (p16/p14(ARF)) gene. No tumour-associated mutations were detected except in 1 melanoma where we found a CC>T* deletion-mutation in the codon 151-152 (exon 5) of the p53 gene. On the basis of our preliminary results, we did extended genotyping of the 500 C>G and 540 C>T polymorphisms in the 3'UTR of the CDKN2A gene in 229 melanoma cases and 235 controls. The T-allele frequency (for 540 C>T polymorphism) in melanomas was significantly higher than in controls (0.14 vs. 0.08; chi(2) = 5.95, p = 0.01; OR = 1.71, 95%CI = 1.11-2.66). The heterozygote frequency for this polymorphism was 0.26 (59/229) in melanomas compared to 0.13 (30/235) in healthy controls (chi(2) = 11.4; p = 0.0007; OR = 2.34, 95% CI = 1.40-3.92). The frequency of the 500 C>G polymorphism in the 3'UTR in the CDKN2A gene was not significantly higher in melanomas compared to healthy controls. The 500 C>G polymorphism, however, was in linkage disequilibrium with approximately 50 kb apart the C>A intronic polymorphism in the CDKN2B gene (determined in 44 melanomas and 90 controls; Fisher exact test, p<0.0001). Finally, the sequence analysis of genomic DNA isolated from T cell lymphocytes of healthy individuals exhibited that the codon reported as last of exon 2 of the CDKN2C gene is rather the first codon of exon 3.

Novel 5-vinyl pyrimidine nucleosides with potent anti-hepatitis B virus activity

Synthesis and antiviral activities of novel N-1 alkyl substituted pyrimidines, 1-[(2-hydroxyethoxy)methyl]-5-vinyluracil (5), 1-[(2-hydroxy-1-(hydroxymethyl)ethoxy)methyl]-5-vinyluracil (6), and 1-[4-hydroxy-3-(hydroxymethyl)-1-butyl]-5-vinyluracil (7) are reported. Compounds 6 and 7 were potent inhibitors of DHBV in cell culture, in contrast, all of the compounds described were devoid of activity against TK(+) HSV-1 and TK(-) HSV-1.

The ORF3 protein of hepatitis E virus binds to Src homology 3 domains and activates MAPK

The hepatitis E virus (HEV) is the causative agent of hepatitis E, an acute form of viral hepatitis. The biology and pathogenesis of HEV remain poorly understood. We have used in vitro binding assays to show that the HEV ORF3 protein (pORF3) binds to a number of cellular signal transduction pathway proteins. This includes the protein tyrosine kinases Src, Hck, and Fyn, the p85alpha regulatory subunit of phosphatidylinositol 3-kinase, phospholipase Cgamma, and the adaptor protein Grb2. A yeast two-hybrid assay was used to further confirm the pORF3-Grb2 interaction. The binding involves a proline-rich region in pORF3 and the src homology 3 (SH3) domains in the cellular proteins. Competition assays and computer-assisted modeling was used to evaluate the binding surfaces and interaction energies of the pORF3.SH3 complex. In pORF3-expressing cells, pp60(src) was found to associate with an 80-kDa protein, but no activation of the Src kinase was observed in these cells. However, there was increased activity and nuclear localization of ERK in the pORF3-expressing cells. These studies suggest that pORF3 is a viral regulatory protein involved in the modulation of cell signaling. The ORF3 protein of HEV appears to be the first example of a SH3 domain-binding protein encoded by a virus that causes an acute and primarily self-limited infection.

Pancytopenia--a six year study

All cases of pancytopenia seen over a six year period in two hematology centres were analysed. Patients receiving myelotoxic chemotherapy or those with leukemic cells in peripheral smear were excluded. There were a total of 166 cases. The four major causes were: aplastic anaemia in 49, megaloblastic anaemia in 37, aleukemic leukemia or lymphoma in 30 and hypersplenism in 19 cases. Bone marrow aspiration was often unsuccessful in obtaining an adequate sample, while biopsy was usually diagnostic. Both bone marrow aspiration and biopsy should be performed simultaneously in pancytopenic patients when the diagnosis is elusive. Megaloblastic anaemia is a major cause of pancytopenia, and may present acutely in the critically ill. It is a rapidly correctable disorder and should not be missed.

Angiotensin converting enzyme insertion allele in relation to high altitude adaptation

Angiotensin converting enzyme (ACE) gene I/D polymorphism has been associated with high altitude (HA) disorders as well as physical performance. We, however, envisage that the polymorphism may be associated with adaptation to the hypobaric hypoxia of altitude, thus facilitating physical performance. For this purpose, three unrelated adult male groups, namely (1) the Ladakhis (HLs), who reside at and above a height of 3600 m, (2) lowlanders, who migrated to Ladakh (MLLs), and (3) resident lowlanders (LLs), have been investigated. The HLs had significantly (p & 0.001) greater numbers of the II homozygotes and the ID heterozygotes than the DD homozygotes, the genotype distribution being 0.46, 0.43 and 0.11 for II, ID and DD genotypes respectively. The MLLs comprised 60% II homozygotes, which was higher (p & 0.001) than the HLs (46%). In the LLs, the heterozygotes were greater (p & 0.001) in number than the II and DD homozygotes. The I allele frequency was 0.72 in the MLLs, 0.67 in the HLs and 0.55 in the LLs. Polymorphism study suggested that the II genotype could be associated with altitude adaptation, which might influence physical efficiency.

The selective serotonin reuptake inhibitor paroxetine is effective in more generalized and in less generalized social anxiety disorder

RATIONALE

The DSM-IV includes the specifier "generalized" to refer to social anxiety disorder (social phobia) patients if the fears include "most social situations". The focus on interventions such as the selective serotonin reuptake inhibitors (SSRIs) for generalized social anxiety disorder arguably runs the risk that inadequate treatment will be provided to patients with the non-generalized or discrete subtypes. There are, however, few data to address whether more generalized and less generalized subgroups of social anxiety disorder differ in response to medication.

OBJECTIVE

To compare response of more generalized and less generalized social anxiety disorder to pharmacotherapy.

METHODS

Data from three randomized placebo-controlled double-blind multicenter trials of the SSRI paroxetine in social anxiety disorder were pooled. Response on the Clinical Global Impression Global Improvement item was analyzed using logistic regression, and change in total Liebowitz Social Anxiety Score was analyzed using analysis of variance, with both models incorporating treatment (paroxetine vs placebo), subgroup (more generalized vs less generalized), demographic, and clinical variables.

RESULTS

The prevalence of more generalized social anxiety disorder was higher in females than in males. However, there was no significant difference in terms of age or clinical characteristics (duration of condition, baseline pulse, mean arterial blood pressure). At treatment endpoint there were significant treatment effects (for paroxetine vs placebo), but no significant subgroup effects (for more generalized vs less generalized).

CONCLUSIONS

Although the current database is limited insofar as few patients with discrete social anxiety disorder would have been included, it is helpful in addressing the value of medication for patients lying on the spectrum from generalized to non-generalized and discrete social anxiety disorder. Paroxetine was effective in both more generalized and in less generalized social anxiety disorder.

Enzyme-linked immunosorbent assay for recombinant K39 antigen in diagnosis and prognosis of Indian visceral leishmaniasis

The recombinant product (rK39) of the 39-amino-acid repeats encoded by a kinesin-like protein-encoding gene of Leishmania chagasi was evaluated by enzyme-linked immunosorbent assay (ELISA) for diagnostic potential and the ability to predict the response to therapy in Indian kala-azar or visceral leishmaniasis (VL); we also compared its performance with that of crude soluble antigen (CSA). At the diagnosis of VL, the anti-rK39 antibody titer was 59-fold higher than the anti-CSA antibody titer. With successful therapy, antibody titers declined steeply at the end of treatment and during follow-up. In contrast, patients who relapsed showed increased titers of antibodies to rK39. The extremely high levels of anti-rK39 antibodies in VL cases suggest the application of rK39 for sensitive and specific serodiagnosis, and rK39 ELISA is also valuable in monitoring drug therapy and detecting relapse of the disease.

Kinetics of human immunodeficiency virus type 1 (HIV) DNA integration in acutely infected cells as determined using a novel assay for detection of integrated HIV DNA

We have developed a novel linker-primer PCR assay for the detection and quantification of integrated human immunodeficiency virus type 1 (HIV) DNA. This assay reproducibly allowed the detection of 10 copies of integrated HIV DNA, in a background of 2 x 10(5) cell equivalents of human chromosomal DNA, without amplifying extrachromosomal HIV DNA. We have used this assay and a near-synchronous one-step T-cell infection model to investigate the kinetics of viral DNA accumulation following HIV infection. We report here that integrated HIV DNA started accumulating 1 h after the first appearance of extrachromosomal viral DNA and accounted for approximately 10% of the total HIV DNA synthesized in the first round of viral replication. These results highlight the efficient nature of integrase-mediated HIV integration in infected T cells.

Polymorphic insertion of additional repeat within an area of direct 8 bp tandem repeats in the 5'-untranslated region of the p53R2 gene and cancer risk

p53R2 is a recently cloned gene that functions in p53-induced DNA repair. In the 5'-untranslated region of the p53R2 gene two direct tandem 8 bp repeats are located. Within the region of these 8 bp direct repeats we have detected the insertion of an additional repeat. In order to determine a possible association of this novel polymorphism with any cancer or population, we carried out genotyping of 843 European and Asian controls and patients with various cancer types. In addition, 26 cancer cell lines were included in the study. No significant difference in polymorphic frequency could be demonstrated for any of the cancer types, although the allelic frequency in melanoma patients was lower than in controls (chi(2) = 3.28; P = 0.07; OR = 0.32; 95% CI 0.07-1.26). A significantly higher frequency of the polymorphism was detected in the compiled Caucasian individuals compared with Asians (chi(2) = 9.19; P = 0.002; OR = 3.13; 95% CI 1.39-7.43). In one tumour cell line we observed two extra inserted copies of the 8 bp repeat. The functional effect of the insertion polymorphism on the p53R2 gene transcription remains to be determined.

Ethnic variation in genotype frequencies of a p53 intron 7 polymorphism

Using a PCR-restriction enzyme-based method we found large ethnic variations when a C-->T polymorphism in the human p53 gene at position 14181 in intron 7 was studied in Finnish, Polish, Hungarian, Italian, Japanese, Indian and Chinese populations. The largest variations were found between Caucasian and Asian, genotype frequencies varied from C 0.95 and T 0.05 in the Finnish population to C 0.67 and T 0.33 in the Chinese population, the relative risk (RR) for T being 6.5 (95% CI 3.4-12.3, P < 0.001). Variations were also found between Finnish and Italian and between Italian and Chinese (RR for T 2.4, 95% CI 1.2-4.9 and 2.7, 95% CI 1.7-4.2, respectively).

Portal system thrombosis: a complication of long-term residence at extreme altitude

BACKGROUND

With induction of the Indian Army to heights over 5,000 meters above sea level, complications of long-term stay at extreme altitude have come to light. We describe our experience with patients developing portal system thrombosis.

METHODS

Clinical data were collected over 2 years on patients hospitalized for thrombotic complications from high-altitude (HAA) and non-high altitude (non-HAA) areas. Site of thrombosis was confirmed by imaging or at surgery. Patients were investigated for conditions that predispose to venous thrombosis.

RESULTS

Ten cases of portal system thrombosis were seen during the period; of these, 9 (mean age 28 [SD 3.9] years; all men) were from HAA. Mean duration of residence in HAA was 12.4 (4.9) months; two were smokers and six drank 7-22 g alcohol/day at least 5 times a week. The first symptom was abdominal pain; this was later complicated by gastrointestinal bleeding (n=5), fever (7), vomiting (7), and weight loss (5). Average time between onset of first symptom and reaching a tertiary-care hospital was 9.5 (4.7) days. Clinical examination showed ascites (8 cases), splenomegaly (7), and hepatomegaly (6). Mean hemoglobin level at admission was 15.8 (3.4) g/dL. Ascites was hemorrhagic; five cases also had large splenic hematoma. The site of thrombosis was splenic vein (7 cases), portal vein (6), and superior (4) and inferior (1) mesenteric vein. None of 5 patients investigated had any prothrombotic condition. Endoscopic/ sonographic evidence of development of collaterals appeared as early as 12-20 days after onset of symptoms.

CONCLUSION

Residence in HAA for extended periods is a risk factor for development of portal system thrombosis. Persistent pain in abdomen in such individuals should raise the possibility of portal system thrombosis.

Synthesis and biological investigations of 5-substituted pyrimidine nucleosides coupled to a dihydropyridine/pyridinium salt redox chemical delivery system

The syntheses, antiviral activities, and partition coefficients (P) of 3'-O-(1-methyl-1,4-dihydropyridyl-3-carbonyl)-coupled nucleosides are described. These novel compounds were designed in an effort to enhance the lipophilicity, and thereby the delivery to the CNS, without compromising the anti-HSV-1 activity of the parental nucleosides. We have previously reported the synthesis of 3'-O-(1-methyl-1,4-dihydropyridyl-3- carbonyl) analogs of 5-iodo-(5), 5-vinyl-(6), and (E)-5-(2-iodovinyl)-2'-deoxyuridines (7). We now report the synthesis of 5-iodo-3'-O-(1-methyl-1,4-dihydropyridyl-3- carbonyl)-5'-O-acetyl-2'-deoxyuridine (15) and 3'-O-(1-methyl-1,4-dihydropyridyl-3-carbonyl)-2'-deoxyuridine (17). Quarternization of the 3'-O-(3-pyridylcarbonyl) compounds (10,12) using iodomethane afforded the corresponding 1-methyl pyridinium salts (13,14) which were reduced with sodium dithionite to yield the corresponding 3'-O-1-methyl-1,4-dihydropyridyl-3-carbonyl compounds (15,16). The deprotection of 3'-O-(1-methyl-1,4-dihydropyridyl- 3-carbonyl)-5'-O-t-butyldimethylsilyl-2'-deoxyuridine (16) with Bu4N+F- afforded 3'-O-(1-methyl-1,4-dihydropyridyl-3-carbonyl)-2'-deoxyuridine (17). Compounds 5-7 and 15 were evaluated for their antiviral activity in vitro against HSV-1, HSV-2, HCMV, and VZV, and were found to retain anti-HSV-1, HSV-2 and VZV activity as compared to their parental nucleosides (1-3). In addition, the cellular toxicity of 3'-O-(1-methyl-1,4-dihydropyridyl-3-carbonyl)-coupled compounds (5-7 and 15) was found to be lower than the parent nucleosides. The lipophilicity of compounds (5-7,15,17) are enhanced substantially, compared to the parent nucleosides, as indicated by an increase in corresponding P values (1-octanol-water) upon replacement of the C-3' hydroxyl by 1-methyl-1,4-dihydropyridyl-3-carbonyl moiety.