Corrections in the CHARMM36 Parametrization of Chloride Interactions with Proteins, Lipids, and Alkali Cations, and Extension to Other Halide Anions.

The nonpolarizable CHARMM force field is one of the most widely used energy functions for all-atom biomolecular simulations. Chloride is the only halide ion included in the latest version, CHARMM36m, and is used widely in simulation studies, often as an electrolyte ion but also as the biological substrate of transport proteins and enzymes. Here, we find that existing parameters systematically underestimate the interaction of Cl- with proteins and lipids. Accordingly, when examined in solution, little to no Cl-association can be observed with most components of the protein, including backbone, polar side chains and aromatic rings. The strength of the interaction with cationic side chains and with alkali ions is also incongruent with experimental measurements, specifically osmotic coefficients of concentrated solutions. Consistent with these findings, a 4-µs trajectory of the Cl--specific transport protein CLC-ec1 shows irreversible Cl- dissociation from the so-called Scen binding site, even in a 150 mM NaCl buffer. To correct for these deficiencies, we formulate a series of pair-specific Lennard-Jones parameters that override those resulting from the conventional Lorentz-Berthelot combination rules. These parameters, referred to as NBFIX, are systematically calibrated against available experimental data as well as ab initio geometry optimizations and energy evaluations, for a wide set of binary and ternary Cl- complexes with protein and lipid analogs and alkali cations. Analogously, we also formulate parameter sets for the other three biological halide ions, namely, fluoride, bromide, and iodide. The resulting parameters are used to calculate the potential of mean force defining the interaction of each anion and each of the protein and lipid analogues in bulk water, revealing association free energies in the range of -0.3 to -3.3 kcal/mol, with the F- complexes being the least stable. The NBFIX corrections also preserve the Cl- occupancy of CLC-ec1 in a second 4-µs trajectory. We posit that these optimized molecular-mechanics models provide a more realistic foundation for all-atom simulation studies of processes entailing changes in hydration, recognition, or transport of halide anions.

Changes in T-lymphocytes in lung cancer patients after hyperthermic intraperitoneal chemotherapy or radiotherapy.

We investigated dynamic changes in T-lymphocyte subsets after hyperthermic intraperitoneal chemotherapy (HIPEC) or radiotherapy using flow cytometry. A total of 1423 lung cancer patients admitted to our hospital between October 2012 and July 2015 were enrolled, and age-matched healthy individuals served as controls. Peripheral blood mononuclear cells (PBMCs) were purified using standard Ficoll density gradient centrifugation, based on which CD3+, CD4+, and CD8+ T-cells were isolated. A surface marker was identified by flow cytometry. Immunohistochemical analysis determined the distribution of the cells in the tumor mass or adjacent tissues. A total of 957 patients (male: 555; female: 402; median age: 49.3 years) with lung cancer who had received only HIPEC or radiotherapy were enrolled. The patients were followed-up until death. No statistical difference was noticed between the patients who had received chemotherapy compared with the baseline levels. A remarkable elevation was noticed in the CD3+ T-cells in the patients three months after radiotherapy (78.71 ± 9.36 vs 68.15 ± 9.65, P < 0.05). The level of CD8+ in the patients who had received chemotherapy or radiotherapy was remarkably elevated in the post-treatment period (P < 0.05). The CD3+ and CD8+ T-cells were mainly expressed in the cytoplasm rather than in the adjacent tissues. The expression of CD3+ and CD4+ was correlated to tumor infiltration and metastasis. Remarkable elevation was noticed in the CD3+ T-cells in the patients three months after radiotherapy. The expression of CD3+ and CD4+ was negatively correlated to tumor infiltration and metastasis in non-small-cell lung cancer patients.

Impact of electronic-cigarette refill liquid on rat testis.

Electronic cigarettes (e-cigarettes) are becoming the fashionable alternative to decrease tobacco smoking, although their impact on health has not been fully assessed yet. The present study was designed to compare the impact of e-cigarette refill liquid (e-liquid) without nicotine to e-liquid with nicotine on rat testis. For this purpose, e-liquid with nicotine and e-liquid without nicotine (0.5 mg/kg of body weight) were administered to adult male Wistar rats via the intraperitoneally route during four weeks. Results showed that e-liquid with or without nicotine leads to diminished sperm density and viability, such as a decrease in testicular lactate dehydrogenase activity and testosterone level. Furthermore, quantitative real-time polymerase chain reaction (qRT-PCR) analysis identified a reduction in cytochrome P450 side-chain cleavage (P450 scc) and 17 beta-hydroxysteroid dehydrogenase (17ßHSD) mRNA level, two key enzymes of steroidogenesis. Following e-liquid exposure, histopathological examination showed alterations in testis tissue marked by germ cells desquamation, disorganization of the tubular contents of testis and cell deposits in seminiferous tubules. Finally, analysis of oxidative stress status pointed an outbreak of antioxidant enzyme activities such as superoxide dismutase, catalase and gluthatione-S-transferase, as well as an important increase in sulfhydril group content. Taken together, these results indicate that e-liquid per se induces toxicity in Wistar rat testis, similar to e-liquid with nicotine, by disrupting oxidative balance and steroidogenesis.

Correlation between polymorphisms in the IL-17A and IL-17F genes and development of coronary artery disease.

A case-control study was conducted to investigate the association between genetic variants of IL-17A rs2275913 and IL-17F rs763780 and the development of coronary artery disease (CAD) in a Chinese population. A total of 306 individuals with CAD and 306 unaffected individuals were enrolled from the Zhengzhou People's Hospital between May 2012 and May 2014. The IL-17A rs2275913 and IL-17F rs763780 genes were genotyped by polymerase chain reaction combined with a restriction fragment length polymorphism (PCR-RFLP). Logistic regression analysis revealed that individuals with the AA genotype of rs2275913 were associated with increased risk of CAD, compared to those with the GG genotype in a codominant model [adjusted odds ratio (OR) = 1.96; 95% confidence interval (CI) = 1.10-3.53]. On the other hand, the AA genotype of rs2275913 was correlated with moderately increased risk of CAD compared to the GG + GA genotype (adjusted OR = 1.76; 95%CI = 1.02-3.07) in a recessive model. However, no significant differences were observed between polymorphisms at the IL-17F rs763780 locus and CAD risk, in codominant, dominant, and recessive models. In conclusion, the results of our study suggested that the IL-17A rs2275913 polymorphism may affect the development of CAD; however, no significant association was observed between the IL-17F rs763780 polymorphism and risk of CAD.

Efficacy of dendritic cell-cytokine-induced killer immunotherapy plus intensity-modulated radiation therapy in treating elderly patients with esophageal carcinoma.

We investigated the clinical efficacy of adoptive cytokine-induced killer (CIK) cell and dendritic cell (DC) therapy plus intensity-modulated radiation therapy (IMRT) for treating elderly patients with esophageal carcinoma (EC). In total, 68 elderly patients with EC were randomized to receive IMRT plus DC-CIK immunotherapy (study group, N = 34) or IMRT only (control group, N = 34). Clinical efficacy, immune function, toxicity and side effects, and life quality were evaluated after treatment. The efficacy rate was significantly higher in the study group than in the control group. Remarkable increases were noted for quality of life and immune function in the study group relative to the control group. Regarding toxicity and side effects, compared with the control group, the study group displayed a higher fever rate, a lower incidence rate of bone marrow suppression, and a similar rate of digestive tract reactions. DC-CIK immunotherapy plus IMRT exhibited better short-term efficacy than IMRT alone in elderly patients with EC. The therapy could improve patients'quality of life and immune function, decrease bone marrow suppression, and lengthen survival time.

Molecular genetic diversity and genetic structure of Vietnamese indigenous pig populations.

The study characterized genetic diversity and genetic structure of five indigenous pig populations (Ha Lang, Muong Te, Mong Cai, Lung and Lung Pu), two wild pig populations (Vietnamese and Thai wild pigs) and an exotic pig breed (Yorkshire) using FAO/ISAG recommended 16 microsatellite markers in 236 samples. All estimated loci were very polymorphic indicated by high values of polymorphism information content (from 0.76 in S0225 to 0.92 in Sw2410). Indigenous populations had very high level of genetic diversity (mean He = 0.75); of all indigenous breeds, Lung Pu showed highest mean number of alleles (MNA = 10.1), gene diversity (He = 0.82), allele richness (5.33) and number of private alleles (10). Thirteen percentage of the total genetic variation observed was due to differences among populations. The neighbour-joining dendrogram obtained from Nei's standard genetic distance differentiated eight populations into four groups including Yorkshire, two wild populations, Mong Cai population and a group of four other indigenous populations. The Bayesian clustering with the admixture model implemented in Structure 2.1 indicated seven possible homogenous clusters among eight populations. From 79% (Ha Lang) to 98% (Mong Cai). individuals in indigenous pigs were assigned to their own populations. The results confirmed high level of genetic diversity and shed a new light on genetic structure of Vietnam indigenous pig populations.

Modeling evolution of resistance by Maruca vitrata (Lepidoptera: Crambidae) to transgenic insecticidal cowpea in Africa.

We created a detailed model of the Maruca vitrata (F.) and cowpea [Vigna unguiculata (L.) Walp] system to study the possible evolution of resistance by the insect to transgenic insecticidal cowpea, which is under development. We focused on population dynamics and genetics in a region of west Africa. We simulated single-toxin and pyramided (two-toxin) cowpea and emphasized conservative, worst-case scenarios in our analysis. The results indicate that as long as a pyramided, transgenic cowpea can be developed, seed saving by farmers and reliance on natural refuge are not major problems for resistance management. Furthermore, it is possible that one or both toxins in the pyramid may not need to be high dose for evolution to be delayed significantly (>20 yr or 80 generations for resistance to become a concern if transgenic cowpea is deployed in areas where M. vitrata is endemic). If efforts are made to deploy transgenic cowpea only into the regions where M. vitrata is not endemic, then there is little to no concern with resistance emerging in the M. vitrata population.

[Endoscopic features of esophageal cancer in Dakar, Senegal: study of 76 observations]. / Aspects endoscopiques du cancer de l'oesophage à Dakar (Sénégal): étude de 76 observations.

OBJECTIVE: In response to the lack of cancer register and paucity of publications on esophageal cancer in Senegal, this retrospective descriptive single-center study was undertaken to determine epidemiological, clinical, endoscopic and histological features of the disease at a digestive endoscopy center in Dakar. PATIENTS AND METHOD: Reports describing upper digestive tract endoscopy procedures performed at the Aristide Le Dantec Teaching Hospital in Dakar between January 2006 and December 2009 were reviewed. Cases involving histologically confirmed esophageal cancer were compiled and patient data including age, sex, and indication for endoscopy as well as endoscopic and histological findings were analyzed. RESULTS: A total of 78 reports were collected including 76 patients with suitable data for analysis. Esophageal cancer accounted for 0.97% of upper digestive tract endoscopy procedures performed. Mean patient age was 49 years and the sex-ratio was 1.9. The main indication for endoscopy was dysphagia (92.1%). The most frequent endoscopic finding involved budding lesions with (42%) or without (29%) ulceration. The most common location was the middle third of the esophagus (50%). The most frequent histological type was squamous cell carcinoma (92.1%). CONCLUSION: Esophageal cancer observed at the endoscopy center of the Aristide Le Dantec Teaching Hospital in Dakar mainly affects young male adults. Lesions are generally located in the middle third of the esophagus and corresponded to squamous cell cancer. There is a need to establish a cancer register and to conduct multicentric studies to gain insight into risk factors for esophageal cancer in Senegal.

Insecticidal activity of three plants extracts on the cowpea pod sucking bug, Clavigralla tomentosicollis, STAL (Hemiptera: Coreidae).

In Burkina Faso, farmers commonly use insecticidal plants for crop protection. To understand how insecticidal plant works (their mode of action), we carried out a bioassay on Clavigralla tomentosicollis, the cowpea pod sucking bugs with three insecticidal plants, Cassia nigricans V., Cymbopogon schoenanthus S. and Cleome viscosa L. Three modes of exposures (1) direct contact application, (2) stomach poisoning activity (3) and inhalation toxicity activity, were tested. The results showed a potent contact and stomach toxicity on 1st instars larvae regardless of the three crude extracts. But the plant extracts was less effective with older stages of the insects. A highest effectiveness was recorded with inhalation of vapours of crude extracts regardless of insect stages and type of plants. Implications of these findings are discussed regarding the use of plant extract for controlling pod sucking bugs in cowpea fields.

HLA-DRB1*04 and DRB1*10 are associated with resistance and susceptibility, respectively, in Brazilian and Vietnamese leprosy patients.

The host genetic background has been considered one of the factors that influence leprosy outcome, a chronic infectious disease caused by Mycobacterium leprae. Genome scans demonstrated that the 6p21 region is associated with leprosy and a substantial number of population-based studies analyzing human leukocyte antigen (HLA) class II loci suggested association of HLA-DR with leprosy. However, some studies lacked robustness as they had limited power. Indeed, experimental designs require increased sample size to achieve adequate power, as well as replication studies with independent samples for confirmation of previous findings. In this work, we analyzed the influence of the HLA-DRB1 locus on leprosy susceptibility per se and disease type using a case-control design carried out in Brazilians (578 cases and 691 controls) and a replication study based on a family design in a Vietnamese population (n=194 families). The results showed that HLA-DRB1*10 is associated with susceptibility to leprosy and HLA-DRB1*04 is associated with resistance, both in the Brazilian and Vietnamese populations suggesting that these alleles play an important role in the activation of cellular immune responses against M. leprae.

[Retrospective analysis and modern concept of treatment of the limbs lymphoedema].

Lymphoedema--is a chronic disease, characterized by the volume enhancement of some part of body, more often--of the limbs, as a consequence of tissues oedema, caused by the lymphatic system transport and resorptive function disorder. Modern approaches to lymphoedema treatment foresees combination of conservative and surgical ones, for example, microsurgical, taking into account the oedema character, stage of the disease, the previous treatment efficacy.

In vitro antiretroviral activity and in vitro toxicity profile of SPD754, a new deoxycytidine nucleoside reverse transcriptase inhibitor for treatment of human immunodeficiency virus infection.

SPD754 (AVX754) is a deoxycytidine analogue nucleotide reverse transcriptase inhibitor (NRTI) in clinical development. These studies characterized the in vitro activity of SPD754 against NRTI-resistant human immunodeficiency virus type 1 (HIV-1) and non-clade B HIV-1 isolates, its activity in combination with other antiretrovirals, and its potential myelotoxicity and mitochondrial toxicity. SPD754 was tested against 50 clinical HIV-1 isolates (5 wild-type isolates and 45 NRTI-resistant isolates) in MT-4 cells using the Antivirogram assay. SPD754 susceptibility was reduced 1.2- to 2.2-fold against isolates resistant to zidovudine (M41L, T215Y/F, plus a median of three additional nucleoside analogue mutations [NAMs]) and/or lamivudine (M184V) and was reduced 1.3- to 2.8-fold against isolates resistant to abacavir (L74V, Y115F, and M184V plus one other NAM) or stavudine (V75T/M, M41L, T215F/Y, and four other NAMs). Insertions at amino acid position 69 and Q151M mutations (with or without M184V) reduced SPD754 susceptibility 5.2-fold and 14- to 16-fold, respectively (these changes gave values comparable to or less than the corresponding values for zidovudine, lamivudine, abacavir, and didanosine). SPD754 showed similar activity against isolates of group M HIV-1 clades, including A/G, B, C, D, A(E), D/F, F, and H. SPD754 showed additive effects in combination with other NRTIs, tenofovir, nevirapine, or saquinavir. SPD754 had no significant effects on cell viability or mitochondrial DNA in HepG2 or MT-4 cells during 28-day exposure at concentrations up to 200 microM. SPD754 showed a low potential for myelotoxicity against human bone marrow. In vitro, SPD754 retained activity against most NRTI-resistant HIV-1 clinical isolates and showed a low propensity to cause myelotoxicity and mitochondrial toxicity.

A histopathologic investigation of PGE(2) pathways as predictors of proliferation and invasion in urothelial carcinomas of the bladder.

INTRODUCTION AND OBJECTIVES: The pattern of arachidonate acid (AA) transformation in tumor cells has been shown to play a role in determining tumor cell invasiveness. AA is released from membrane phospholipids by cPLA(2). Then it is metabolized into prostaglandins and PGE(2) especially via cyclooxygenase pathways. PGE(2) production seems to be necessary for rendering the cells invasive. We aimed to characterize cPLA(2), cyclooxygenase 2 (COX2) and prostaglandine E synthase (PGES) expression in human transitional carcinoma (TCC) of the urinary bladder and correlate with the Ki-67 proliferating marker. METHODS: Formalin-fixed human TCC tissues (n=54) obtained from TURB or cystectomies were evaluated for cPLA(2), COX2, PGES and Ki-67 expression using specific antibodies. There were 6 CIS, 9 pTaG1, 9 pTaG3, 10 pT1G3 and 10 pT2G3. 10 normal bladder tissues were also evaluated. Control slides were incubated without primary antibodies and treated in a similar way. RESULTS: cPLA(2), COX2 and PGES were not expressed in the 10 normal tissues. In the same normal tissues, Ki-67 expression was observed only in 1% of the cells. However, cPLA(2) was expressed in 1/6 CIS, 1/9 pTaG1, 3/9 pTaG3, 6/10 pT1G3 and 2/10 pT2G3. COX2 was expressed in 0/6 CIS, 0/10 pTaG1, 2/9 pTaG3, 3/10 pT1G3 and 1/10 pT2G3. PGES was expressed in 4/6 CIS, 0/9 pTaG1, 4/9 pTaG3, 2/10 pT1G3 and 5/10 pT2G3. Ki-67 expression was 39.5% for CIS, 6.5% in pTaG1, 37% in pTaG3, 34.5% in pT1G3 and 55% in pT2G3. If we consider it a positive result when at least one enzyme was expressed, there were 5/6 CIS positive, 1/9 pTaG1 positive, 9/9 pTaG3 positive, 10/10 pT1G3 positive and 10/10 pT2G3 positive. Also the Ki-67 is more often expressed in cells with high grade tumor. CONCLUSIONS: These results suggest that (i). not only COX2 is involved in the tumorogenesis of the TCC but also cPLA(2) and PGES, (ii). there is relationship between the AA metabolic PGE(2) pathway expression and the aggressiveness of the TCC of the urinary bladder.

High glucose and hyperinsulinemia stimulate connective tissue growth factor expression: a potential mechanism involved in progression to fibrosis in nonalcoholic steatohepatitis.

Nonalcoholic steatohepatitis (NASH) may progress to liver fibrosis and cirrhosis. Mechanisms directly involved in the development of fibrosis have been poorly investigated. Because connective tissue growth factor (CTGF) is an intermediate key molecule involved in the pathogenesis of fibrosing chronic liver diseases and is potentially induced by hyperglycemia, the aims of this study were to (1) study the expression of CTGF in vivo both in human liver biopsy specimens of patients with NASH and in an experimental model of obesity and type II diabetes (Zucker rats); and (2) analyze the effects of hyperglycemia and insulin in vitro on hepatic stellate cells. In vivo, CTGF overexpression was observed in the liver tissue of all of the 16 patients with NASH. CTGF immunostaining was mild in 7 cases (44%) and moderate or strong in 9 cases (56%). Staining was mainly detected in the liver extracellular matrix in parallel with the amount of liver fibrosis. Liver from fa/fa rats also showed CTGF overexpression by comparison with Fa/fa rats both at the messenger RNA (mRNA) level (3-fold increase) and protein level. In vitro, both CTGF mRNA and protein were significantly increased when hepatic stellate cells were incubated with either glucose or insulin. A slight increase in type I procollagen mRNA level was also observed in hepatic stellate cells incubated with glucose. In conclusion, this study suggests that hyperglycemia and insulin are key-factors in the progression of fibrosis in patients with NASH through the up-regulation of CTGF.

Replicative senescence in normal liver, chronic hepatitis C, and hepatocellular carcinomas.

There is growing evidence that senescent cells accumulate in vivo and are associated with the aging process in parallel with the progressive erosion of telomeres. Because recent data show that telomere shortening is involved in the pathogenesis of liver cirrhosis, we looked for replicative senescence cells in normal livers, chronic hepatitis C, and hepatocellular carcinoma (HCC). Replicative senescent cells were detected on liver tissue cryosections using expression of a specific marker, senescence-associated beta-galactosidase, a cytoplasmic enzyme detected at pH 6. A total of 57 frozen liver samples (15 normal liver, 32 chronic hepatitis C, and 10 HCCs) were studied. Replicative senescence was graded as absent in 56% of cases (32 of 57) and present in 44% (25 of 57). Replicative senescence was considered present in 3 of 15 normal livers (20%), 16 of 32 chronic hepatitis cases (50%), and 6 of 10 HCCs (60%). In the group of nontumoral livers, the presence of senescent cells in liver was associated with older age (P =.03). In the group with chronic hepatitis C, fibrosis stage, but not activity grade, was significantly correlated with the accumulation of replicative senescent cells (P <.001). Finally, beta-Gal staining in nontumoral tissue was strongly correlated with the presence of HCC in the surrounding liver (P <.001). These results suggest that chronic hepatitis C represents a relevant model of accelerated replicative senescence and that accumulation of replicative senescent cells predispose to HCC development. Detection of replicative senescent cells may then serve as a predictive marker of a hepatocellular carcinoma in the surrounding tissue. HUM PATHOL 32:327-332.

Development of novel nucleoside analogues for use against drug resistant strains of HIV-1.

Nucleoside analogue inhibitors of the reverse transcriptase (RT) enzyme of HIV-1 were the first class of compounds to be used in anti-HIV-1 therapy and are a cornerstone in highly active antiretroviral therapy. Despite the number of inhibitors of HIV-1 RT available for clinical use at the present time and the effectiveness of these compounds in combination regimens, long-term exposure of patients to these drugs often results in the development of viral resistance or long-term toxicity. For this reason, efforts to identify new agents with activity against drug-resistant strains of HIV-1 and with a toxicity profile that allows for individual patient tolerance of the drugs are still warranted.

Clonal analysis of micronodules in virus C-induced liver cirrhosis using laser capture microdissection (LCM) and HUMARA assay.

Most hepatocellular carcinomas (HCC) arise from malignant transformation of regenerative cirrhotic nodules. Because HCC has a very poor prognosis, detection of these premalignant lesions may improve the management of patients with cirrhosis. In this regard, clonal analysis of liver micronodules should be of particular interest in order to differentiate polyclonal regenerative micronodules from monoclonal neoplastic potentially malignant micronodules. To address this issue, 112 micronodules from 15 cases of explanted liver cirrhosis were carefully microdissected from paraffin-embedded tissue using a laser capture microscopy system. Clonal analysis was performed by analyzing X-chromosome inactivation, as indicated by the methylation status of the human androgen receptor gene (HUMARA). For each microdissected micronodule, a large set of pathological features was evaluated and correlated with their clonal status. Clonal analysis showed that 57 micronodules (51%) were monoclonal and 55 (49%) were polyclonal. Prevalence of monoclonal nodules ranged from 25% to 71% according to cases. In all cases, mono- and polyclonal nodules were randomly distributed in the cirrhotic liver. Although the clonal status was not significantly affected by the presence or absence of macronodules in the adjacent liver, size of monoclonal micronodules was significantly larger than size of polyclonal micronodules (mean size of the monoclonal nodules: 3 + 0.1 mm vs mean size of the polyclonal nodules: 2.5 +/- 0.1 mm, p = 0.007). Among the elementary pathological features evaluated, only the presence of iron overload was correlated with a monoclonal status (p = 0.04). In conclusion, clonal analysis of liver cirrhosis shows that 51% of micronodules are monoclonal lesions, supporting the notion that liver cirrhosis is a multineoplastic lesion. Because monoclonality is a marker of neoplasia, cirrhosis with accumulation of monoclonal nodules may be carefully followed, and monoclonal nodules should be screened for additional markers to assess their biological behavior.

Synthesis and antiviral activities of N-9-oxypurine 1,3-dioxolane and 1,3-oxathiolane nucleosides.

Two series of 1,3-dioxolanes and 1,3-oxathiolane nucleosides containing N-9-oxypurine were synthesized as potential antiviral agents. These compounds were prepared by reacting the sugar moieties with iodo- or bromotrimethylsilane, followed by treatment with a mixture of sodium hydride and the desired N-hydroxy purine base. The preparation of these N-hydroxybases was also described. No significant antiviral activity was observed against HIV, HBV, HSV-1, HSV-2, or HCMV.

Expression of vascular endothelial growth factor in renal cell carcinomas.

Vascular endothelial growth factor (VEGF) is an angiogenic factor that may be involved in tumor growth and metastasis. Only a few data concerning the role of VEGF in renal cell carcinomas (RCCs) are available, and no studies have yet evaluated its prognostic value. The aim of the present study was to assess VEGF expression in a large series of renal tumors with a long follow-up, correlated with the usual histoprognostic factors and survival. VEGF immunostaining was performed on formalin-fixed, paraffin-embedded archival tissue from 74 renal carcinomas (62 conventional renal cell and 12 papillary carcinomas). Positivity of immunostaining was semi-quantitatively scored by two pathologists. Angiogenesis was evaluated by immunostaining with anti-CD34 antibodies on serial sections. Cytoplasmic VEGF expression was detected in tumor cells in 35% (26/74) of RCCs, including 18 out of the 62 (29%) conventional RCCs and 8 out of the 12 (67%) papillary carcinomas (P=0.02). In the group of conventional RCCs, VEGF expression was positively correlated with both nuclear grade (P=0.05) and size of the tumor (P=0.05). Furthermore, a significant correlation was observed between VEGF expression and microvascular count (P=0.04). Finally, cumulative survival rate was significantly lower in the group of patients with conventional RCCs expressing VEGF (log rank test, P=0.01). In the Cox model, VEGF expression was a significant independent predictor of outcome, as well as stage and nuclear grade. This study suggests that VEGF is involved in angiogenesis in conventional RCCs and appears to be a potential prognostic factor in these tumors.

Mechanism of action and in vitro activity of 1',3'-dioxolanylpurine nucleoside analogues against sensitive and drug-resistant human immunodeficiency virus type 1 variants.

(-)-Beta-D-1',3'-Dioxolane guanosine (DXG) and 2,6-diaminopurine (DAPD) dioxolanyl nucleoside analogues have been reported to be potent inhibitors of human immunodeficiency virus type 1 (HIV-1). We have recently conducted experiments to more fully characterize their in vitro anti-HIV-1 profiles. Antiviral assays performed in cell culture systems determined that DXG had 50% effective concentrations of 0.046 and 0.085 microM when evaluated against HIV-1(IIIB) in cord blood mononuclear cells and MT-2 cells, respectively. These values indicate that DXG is approximately equipotent to 2', 3'-dideoxy-3'-thiacytidine (3TC) but 5- to 10-fold less potent than 3'-azido-2',3'-dideoxythymidine (AZT) in the two cell systems tested. At the same time, DAPD was approximately 5- to 20-fold less active than DXG in the anti-HIV-1 assays. When recombinant or clinical variants of HIV-1 were used to assess the efficacy of the purine nucleoside analogues against drug-resistant HIV-1, it was observed that AZT-resistant virus remained sensitive to DXG and DAPD. Virus harboring a mutation(s) which conferred decreased sensitivity to 3TC, 2',3'-dideoxyinosine, and 2',3'-dideoxycytidine, such as a 65R, 74V, or 184V mutation in the viral reverse transcriptase (RT), exhibited a two- to fivefold-decreased susceptibility to DXG or DAPD. When nonnucleoside RT inhibitor-resistant and protease inhibitor-resistant viruses were tested, no change in virus sensitivity to DXG or DAPD was observed. In vitro drug combination assays indicated that DXG had synergistic antiviral effects when used in combination with AZT, 3TC, or nevirapine. In cellular toxicity analyses, DXG and DAPD had 50% cytotoxic concentrations of greater than 500 microM when tested in peripheral blood mononuclear cells and a variety of human tumor and normal cell lines. The triphosphate form of DXG competed with the natural nucleotide substrates and acted as a chain terminator of the nascent DNA. These data suggest that DXG triphosphate may be the active intracellular metabolite, consistent with the mechanism by which other nucleoside analogues inhibit HIV-1 replication. Our results suggest that the use of DXG and DAPD as therapeutic agents for HIV-1 infection should be explored.