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Biomedical subjects

P Ray

Publications and source records attributed to P Ray.

At least 19 recordsLinked to original sources
PubMed1995

The potential for normal tissue dose reduction with neoadjuvant hormonal therapy in conformal treatment planning for stage C prostate cancer.

PURPOSE: Preirradiation hormonal cytoreduction of prostate cancer has been proven to reduce exposure of normal structures by decreasing the size of the target volume. Dose-volume histogram (DVH) analysis, however, does not always appear to demonstrate a strong positive benefit with the use of neoadjuvant hormone therapy. This study analyzes various other factors influencing dose to normal organs, which may determine the success or failure of neoadjuvant hormonal therapy in achieving its goals. METHODS AND MATERIALS: Patients with bulky clinical Stage C adenocarcinoma of the prostate were given 3 months of hormone treatment consisting of oral Flutamide and monthly Zoladex injections prior to irradiation. Computerized tomography (CT) scans of the pelvis were obtained both prior to and following hormonal treatment. Treatment plans were generated by three-dimensional (3D) conformal treatment planning. The change in the volume of the prostate was assessed along with the percentage of prescribed dose delivered to the rectum and bladder. Various factors such as prostate size, bladder/rectum size, and organ shape were studied. Both dose-volume histograms (DVH) and dose-surface area histograms (DSH) were used for analysis. RESULTS: Six of seven patients had reduction in the size of their prostates. The mean volumes of the prostate before and after hormonal manipulation were 129.1 +/- 32.9 standard deviation (SD) cm3 and 73.0 +/- 29.5 SD cm3, respectively (p = 0.0059). The volume of rectum receiving 80% of the prescribed dose was reduced in five of seven patients from a mean of 83.2 to 59.9 cm3 (p = 0.045). The volume of bladder receiving 80% of the prescribed dose was also reduced in five out of seven patients from a mean of 74.5 to 40.2 cm3 (p = 0.098). Correlation between the size of the prostate and volume of rectum and bladder treated was not always consistent: greater reduction in prostate size did not necessarily result in large decreases in dose to bladder or rectum. The total size of the bladder and rectum were found to be important factors in normal tissue radiation exposure; the benefits of hormone therapy may be lost if the bladder and rectum are allowed to decrease in size. Also, the bladder may be prone to sagging into the pelvis of some patients following hormone therapy, resulting in a less optimal therapeutic ratio. CONCLUSION: Reduction in prostate size by neoadjuvant hormonal manipulation does decrease the amount of normal tissue irradiated in most patients. However, the correlation between the reduction in prostate size and amount of rectum or bladder treated is not linear if other variables are not controlled. Factors such as the shape of the organs, as well as the distensible nature of the bladder and rectum, play major roles in dose to normal tissues. These facts may mask the benefits of cytoreduction and could be obstacles in realizing consistent benefits from preirradiation hormonal treatment in the clinical setting if they are ignored.

Adenocarcinoma↗
PubMed1995

Activation of the interleukin-5 promoter by cAMP in murine EL-4 cells requires the GATA-3 and CLE0 elements.

Interleukin-5 (IL-5) plays a central role in the growth and differentiation of eosinophils and contributes to several disease states including asthma. Accumulating evidence suggests a role for cAMP as an immunomodulator; agents that increase intracellular cAMP levels have been shown to inhibit production of cytokines predominantly produced by T helper (Th) 1 cells such as IL-2 and interferon gamma (IFN-gamma). In contrast, the production of IL-5, predominantly produced by Th2 cells, is actually enhanced by these agents. In this report, we have performed transient transfection experiments with IL-5 promoter-reporter gene constructs, DNase I footprinting assays, and electrophoretic mobility shift assays to investigate the key regulatory regions necessary for activation of the IL-5 promoter by dibutyryl cAMP and phorbol esters in the mouse thymoma line EL-4. Taken together, our data demonstrate the critical importance of two sequences within the IL-5 5'-flanking region for activation by these agents in EL-4 cells: one, a highly conserved 15-base pair element present in genes expressed by Th2 cells, called the conserved lymphokine element 0 (CLE0; located between -53 and -39 in the IL-5 promoter), and the other, two overlapping binding sites for the transcription factor GATA-3 (but not GATA-4) between -70 and -59. Taken together, our data suggest that activation via the unique sequence combination GATA/CLE0 results in selective expression of the IL-5 gene in response to elevated levels of intracellular cAMP.

Animals↗
PubMed1995

Interleukin 4-inducible phosphorylation of HMG-I(Y) is inhibited by rapamycin.

The non-histone chromosomal protein HMG-I(Y) participates in repression of transcription directed by a promoter which confers interleukin 4 (IL-4)-inducible activation in transfected B cell lines. Metabolic labeling, phosphoamino acid analyses, and in vitro phosphorylation studies demonstrate that IL-4 induces serine phosphorylation of HMG-I(Y) in B lymphocytes. Phosphopeptide mapping shows that the predominant site of phosphorylation contains a casein kinase II consensus motif. The immunosuppressive agent rapamycin has been shown preferentially to inhibit IgE production by IL-4-treated human B cells. It is shown here that rapamycin inhibits both activation of the human germ line epsilon promoter by IL-4 and IL-4-inducible phosphorylation of HMG-I(Y). These findings demonstrate a rapamycin-sensitive pathway that transduces signals from the IL-4 receptor to nuclear factors that regulate inducible transcription. The affinity of normal nuclear HMG-I(Y) for DNA is increased by dephosphorylation in vitro, whereas in vitro kinase reactions using casein kinase II decrease recombinant HMG-I(Y) binding to DNA. These data further suggest a novel mechanism in which phosphorylation triggered by IL-4 or other cytokines could regulate the effects of HMG-I(Y) on gene transcription.

Amino Acid Sequence↗
PubMed1995

Infection of baboons with simian/human immunodeficiency viruses.

Baboons were evaluated for their utility to serve as a model for testing envelope-based vaccines against human immunodeficiency virus type 1 (HIV-1). The ability of HIV-1 strains IIIB, RF, and SF2 to infect baboons was compared with that of simian/human immunodeficiency virus (SHIV) recombinant viruses comprised of either HXB2 or SF2 env, tat, rev, and vpu genes inserted into the SIVmac239 backbone. Both SHIV recombinants replicated in baboon PBMC in vitro, while no evidence of replication was noted for HIV-1 strains (MN, IIIB, SF2). Infection of baboons in vivo correlated with the restriction of infection in vitro. Virus was recovered by cocultivation methods early after SHIV (HXBc2) infection of two baboons with seroconversion profiles that parallel those observed in simian immunodeficiency virus (SIV)mac-infected rhesus monkeys. One of two baboons inoculated with SHIV(SF2) also seroconverted within 4 weeks; however, the kinetics of infection in a second animal appeared much later, with seroconversion to gp120 not evident until 20 weeks and no virus recovery during 32 weeks following infection. Viral DNA was detected in the lymph nodes of the SHIV-inoculated animals by nested polymerase chain reaction (PCR) amplification. Histopathologic changes were evident in lymph nodes, yet no overt clinical disease was observed. When HIV-1 strains (IIIB, RF, and SF2) were inoculated into baboons, virus was not recovered and no seroconversion to the major HIV-1 antigens was observed. However, viral DNA from the lymph nodes of four animals inoculated with HIV-1 strains could be detected by nested PCR, indicating a persistent but diminutive infection of HIV-1. The baboon thus represents a new animal model for testing HIV-1 envelope-based vaccines including the evaluation of new immunogens, dosages, routes, and adjuvants that act in eliciting protective responses.

Animals↗
PubMed1995

Cloning of a differentially expressed I kappa B-related protein.

We have cloned a cDNA corresponding to a novel gene from a human epithelial cell line by subtractive hybridization and polymerase chain reaction techniques. This gene is expressed at the message level and at the protein level in a lung alveolar type II-like epithelial cell line but not in lung fibroblasts. In adult human tissues, the mRNA for this gene was detected only in the heart and the skeletal muscle, but not in the brain, placenta, whole lung, liver, or kidney. We have named this gene I kappa BR (for I kappa B-related) since its 52-kDa protein product has significant homology to the I kappa B family of proteins which function as inhibitory cytoplasmic retention proteins for the vertebrate rel/NF-kappa B transcription factors. Although the important role of NF-kappa B in gene activation in cells of the immune system is now well established, a similar role in other cell types or in vertebrate development is less clear. The deduced amino acid sequence of I kappa BR has the most significant homology to the Drosophila protein Cactus which inhibits the function of the NF-kappa B-like protein Dorsal. In electrophoretic mobility shift experiments, I kappa BR inhibited the ability of the p50:p65 NF-kappa B heterodimer to bind DNA. The DNA binding ability of the p50 homodimer but not the p65 homodimer was drastically inhibited by I kappa BR. In transfection experiments, overexpression of I kappa BR significantly inhibited NF-kappa B-dependent transcription from the Ig kappa enhancer. This new member of the I kappa B family of proteins, I kappa BR, may play an important role in regulation of NF-kappa B function in epithelial cells.

Amino Acid Sequence↗
PubMed1995

Western blot analysis of cerebrospinal fluid for detection of Aspergillus antigens.

Western-blot immunoassay of cerebrospinal fluid (CSF) specimens of patients with central nervous system (CNS) aspergillosis (3), CNS candidosis (1) and bacterial meningitis (2) was carried out using pooled serum from histopathologically proven deep-seated aspergillosis cases to detect unique antigenic fractions for aspergillosis in CSF. No reactivity was observed in patients with non-fungal meningitis. Four cross-reactive bands (40, 90, 200 and > 200 KD) were detectable in CSF from patients with both aspergillosis and candidosis of the CNS. Four additional bands (90-200 KD) were consistently present only in patients with aspergillosis. One prominent band (110 KD) was found only in the patient with aspergillosis who had a fatal outcome and raised the possibility of being a poor prognostic marker.

Adolescent↗
PubMed1995

Neoadjuvant chemotherapy of locally advanced non-small cell lung cancer.

Neoadjuvant chemotherapy was tested in non-small cell lung cancer in an attempt to increase the resectability of the tumor and to treat the microscopic metastatic disease known to be responsible for the majority of failures in surgically treated patients. This review deals with published trials. Most of them are feasibility studies in Stage III NSCLC. Obviously, the heterogeneity of eligibility criteria from one study to another prevents general conclusions on the usefulness of neoadjuvant chemotherapy. However, it is possible to conclude that neoadjuvant chemotherapy has an antitumor activity; the majority of the studies report a 60% objective response rate including a significant number of complete responses and a 50% complete resection rate. Neoadjuvant chemotherapy does not increase morbidity after surgery except when it is combined with preoperative radiation therapy. At the time of writing, one Phase III randomized study comparing neoadjuvant chemotherapy followed by surgery with surgery alone has been published. This study concludes that the combined modality treatment improves the survival of patients with locally advanced non-small cell lung cancer. Taken as a whole, the literature deserves further studies to determine the place of neoadjuvant chemotherapy in lung cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

[Evaluation of tumor response during chemotherapy of bronchial cancer].

Chemotherapy of lung cancer is still an experimental approach requiring careful evaluation. Tumour response (marker of anticancer activity) is not perfectly correlated to survival (marker of chemotherapy efficacy), but its evaluation remains a milestone inasmuch as reporting a wrong tumour response rate might lead to the rejection of active new treatments. This review deals with the method of tumour response measurements and its use during a chemotherapy protocol. Recommendations drawn from the analysis of the literature are: 1) to assess and classify all lesions which can be identified at the beginning of the treatment; 2) to define the target lesions, mainly the ones which can be bidimensionally measured; 3) to use the World Health Organization recommendations for reporting the overall response; 4) to confirm complete response by negative rebiopsies; 5) to avoid second fiberoptic bronchoscopy to patients with stable or progressive disease on CT-scan, and finally; 6) to assess response quality by evaluating response duration and improvement of quality of life.

Antineoplastic Agents↗
PubMed1995

Allelic drop-out and preferential amplification in single cells and human blastomeres: implications for preimplantation diagnosis of sex and cystic fibrosis.

Previously the diagnosis of sex and cystic fibrosis status has been studied on single cells using the polymerase chain reaction (PCR). It has been suggested that allelic drop-out (PCR failure of one allele) and/or preferential amplification (hypo-amplification of one allele) may contribute to poor reliability and misdiagnosis, although this remains controversial as some reports suggest that allelic drop-out does not occur. We investigated an improved method of diagnosing sex and cystic fibrosis in single cells using a new technology (fluorescent PCR) to determine the base level of PCR artefacts (allelic drop-out and preferential amplification) which, in combination with improved sensitivity, should improve PCR reliability and accuracy. Fluorescent PCR gives high reliability (approximately 97%) and accuracy rates (approximately 97%) in somatic cells for both sex and cystic fibrosis diagnosis and its lower detection threshold allows allelic drop-out and preferential amplification to be easily distinguished. We also achieved high reliability and accuracy in diagnosing cystic fibrosis in human blastomeres. This study confirms earlier reports of both allelic drop-out and preferential amplification in single cell analysis. We demonstrate that both allelic drop-out and preferential amplification occur in somatic cells and suggest these are separate phenomena. Preferential amplification appeared common in single cell PCR while allelic drop-out apparently occurred at random in each allele. Preferential amplification was mainly amplification of the larger allele. We suggest that some inaccuracy/misdiagnosis may be due to both preferential amplification as well as allelic drop-out. Other findings were variability in drop-out between PCR and that amplification of signals from human blastomeres may be linked to embryo quality. We suggest that allelic drop-out is dependent on the number of cells within the sample.

Alleles↗
PubMed1995

Transgenic models of HIV-1.

Transgenic technology has been very successful at providing insights into possible processes involved in HIV-induced pathogenesis. The availability of these small animal models for the study of HIV-related syndromes including KS, epidermal proliferative lesions, HIV-associated nephropathy, AIDS-related growth failure and cachexia may well facilitate the development of novel therapies for these complications. Other phenotypes created in mice, such as cataracts and hepatic cancer [59], may not have human analogies but may still provide insight into pathogenesis. Thus, transgenic models have already provided resources to study many manifestations of AIDS and others are likely to be developed. The optimal strategy for designing future transgenic animals, however, is less clear. No transgenic mouse model has been generated to date that will provide an avenue for vaccine development. This advance awaits the further discovery of the host factors that facilitate the virus replicative cycle in humans and a better understanding of these pathways in the mouse. For the development of molecular-based therapy, however, the currently available models may well be adequate to test molecular inhibitors of transcription [7,60,61] and post-transcriptional processing of viral mRNA [62]. Whether single or multigenic constructs under the control of the LTR are better or worse for this purpose is a debatable issue. Transgenic technology may yet make an additional contribution to the development of molecular therapy for AIDS. The best method of demonstrating that a gene therapeutic strategy is safe to administer to patients has not been determined. By introducing potentially therapeutic constructs into mice as transgenes, their safety can be assessed in many different cell types in vivo, analogous to toxicological testing in rodents for systemically administered drugs. Thus, transgenic technology has already provided insights into the pathogenesis of HIV-1. While it has not yet proven its utility for vaccine development, transgenic technology holds the promise of being an active participant in the development of both safe and effective gene therapy approaches for the treatment of AIDS.

AIDS Dementia Complex↗
PubMed1994

Down-modulation of interleukin-6 gene expression by 17 beta-estradiol in the absence of high affinity DNA binding by the estrogen receptor.

The mechanism of repression of the interleukin-6 (IL-6) promoter by 17 beta-estradiol (E2) was investigated in cells transfected with wild-type (wt) or mutant estrogen receptor (ER) expression vectors. In transient transfection experiments, IL-1-induced activation of the IL-6 promoter was efficiently inhibited by wt ER. However, estrogen receptors carrying mutations within or over-lapping with the DNA binding domain did not repress IL-6 promoter activity. A mutant receptor lacking the N-terminal transactivator function-1 but retaining the C-terminal transactivator function-2 also repressed activation of the IL-6 promoter. Our recent experiments indicate the requirement for both the nuclear factor (NF)-IL6 and the NF-kappa B sites in the IL-6 promoter for activation by IL-1. We now show that activation of the IL-6 promoter, elicited by a combination of NF-IL6 and the p65 subunit of NF-kappa B, can be inhibited by the wt receptor but not by a receptor containing a mutation in its DNA binding domain. Although a deletion within the DNA binding domain of ER abolished the repressor function of the receptor, a chimeric receptor ER-GR CAS1, in which the DNA binding domain of ER was swapped with the complementary region from the glucocorticoid receptor, retained the inhibitory effects on the IL-6 promoter. This was in contrast to the absolute dependence of ER on its own DNA binding domain for activation of typical estrogen response element-containing promoters, as reported previously by other investigators. Furthermore, the repression of the IL-6 promoter by a combination of ER and E2, unlike activation of estrogen response elements by the same combination, did not appear to be mediated via high affinity binding of the receptor to the promoter. In functional experiments, the transactivator function of ER was totally inhibited by overexpression of p65 and to a lesser extent by that of NF-IL6. These results indicate that ER may repress gene expression in the absence of high affinity DNA binding.

Base Sequence↗
PubMed1994

IL-1 and transforming growth factor-beta regulation of fibroblast-derived IL-11.

IL-11 and IL-6 are fibroblast-derived cytokines with overlapping biologic properties. To determine whether IL-11 and IL-6 are similarly regulated, we characterized the effects of rIL-1 and TGF-beta (beta 1 and beta 2) on human lung fibroblast IL-11 production and compared this regulation with that of IL-6. Unstimulated fibroblasts did not produce significant amounts of IL-11, whereas rIL-1 alpha and TGF-beta were dose-dependent stimulators of IL-11 protein production, mRNA accumulation, and gene transcription. rIL-1 alpha and TGF-beta also interacted in a synergistic fashion to further increase IL-11 protein production and mRNA accumulation. The effects of rIL-1 and TGF-beta individually were not altered by the cyclic nucleotide-dependent protein kinase inhibitor HA1004, protein kinase C (PKC) inhibition with staurosporine, or chronic phorbol ester preincubation, or the calmodulin antagonists W7 and TFP. The effects of rIL-1 alpha and TGF-beta in combination were also unaltered by HA1004, staurosporine, and chronic phorbol ester exposure. A23187, however, did induce IL-11 mRNA accumulation and W7 and TFP did reverse the synergistic stimulation caused by rIL-1 and TGF-beta in combination. In contrast with the regulation of IL-11, TGF-beta did not effectively stimulate IL-6 mRNA accumulation, rIL-1 alpha was a more potent stimulator of IL-6 than IL-11 production, and rIL-1-induced IL-6 mRNA accumulation was augmented by W7 and TFP. These studies demonstrate that: 1) rIL-1, TGF-beta, and agents that increase intracellular calcium stimulate lung fibroblast IL-11; 2) the IL-11 stimulatory effects of rIL-1 and TGF-beta are, at least partially, transcriptionally mediated and are the result of signal transduction pathways that are largely PKC, cyclic nucleotide, and calmodulin independent; and 3) rIL-1 and TGF-beta interact in a synergistic fashion to further increase fibroblast IL-11 production and that this synergy is mediated by a largely PKC- and cyclic nucleotide-independent and calmodulin-dependent activation pathway. Importantly, they also demonstrate that rIL-1 and TGF-beta stimulate lung fibroblast IL-6 and IL-11 production via distinct and differentially regulatable activation pathways.

Calcimycin↗
PubMed1994

Enzymatic synthesis of folate and antifolate polyglutamates with Escherichia coli folylpolyglutamate synthetase.

Escherichia coli folylpolyglutamate synthetase was used to synthesize micromole quantities of polyglutamyl conjugates of folic acid, methotrexate, and other analogs of folic acid. The products of the enzymatic reactions were purified by semipreparative C18 HPLC. The position of each amide linkage (gamma or alpha carboxyl) in the polyglutamated products was determined by limited and exhaustive hydrolyses with hog kidney folylpolyglutamate hydrolase and with yeast carboxypeptidase Y. Under standard reaction conditions, the E. coli enzyme added up to five glutamyl residues to each monoglutamated substrate, primarily at the gamma carboxyl position. Thus, an enzyme which naturally adds only two glutamates to naturally occurring folates can be used synthetically to make higher polyglutamates of a wide range of synthetic substrates. The products of the reactions are valuable tools for the study of the metabolism of antifolate drugs as well as metabolic reactions involving folate cofactors.

Escherichia coli↗
PubMed1994

Inhibition of bioenergetics alters intracellular calcium, membrane composition, and fluidity in a neuronal cell line.

The effect of inhibited bioenergetics and ATP depletion on membrane composition and fluidity was examined in cultured neuroblastoma-glioma hybrid NG108-15 cells. Sodium cyanide (CN) and 2-deoxyglucose (2-DG) were used to block, oxidative phosphorylation and anaerobic glycolysis, respectively. Endoplasmic reticulum (ER) Ca(2+)-pump activity measured by 45Ca2+ uptake was > 92% inhibited in intact cells incubated with CN (1 mM) and 2-DG (20 mM) for 30 min. In addition, exposure of cells to CN and 2-DG caused a 134% increased release of isotopically labeled arachidonic acid (3H-AA) or arachidonate-derived metabolites from membranes. Removal of Ca2+ from the incubation medium ablated the CN/2-DG induced release of 3H-AA or its metabolites. Membrane fluidity of intact cells was measured by electron spin resonance spectroscopy using the spin label 12-doxyl stearic acid. The mean rotational correlation time (tau c) of the spin label increased 49% in CN/2-DG exposed cells compared to controls, indicating a decrease in membrane fluidity. These results show that depletion of cellular ATP results in inhibition of the ER Ca(2+)-pump, loss of AA from membranes, and decreased membrane fluidity. We propose that impaired bioenergetics can increase intracellular Ca2+ as a result of Ca(2+)-pump inhibition and thereby activate Ca(2+)-dependent phospholipases causing membrane effects. Since neurons derive energy predominantly from oxidative metabolism, ATP depletion during brain hypoxia may initiate a similar cytotoxic mechanism.

Adenosine Triphosphate↗