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J B Kopp

Publications and source records attributed to J B Kopp.

At least 19 recordsLinked to original sources
PubMed2002

Congenital nuclear cataracts and uveitis in HIV-transgenic mice.

PURPOSE: Patients infected with HIV-1 develop ocular manifestations, some due to opportunistic infections and others attributed to the virus itself. Among the latter are retinal microvasculopathy and uveitis. We have analysed the ocular phenotype in HIV-transgenic mice. METHODS: We have studied T26 transgenic mice which bear a gag-pol deleted HIV-1 genome. Transgene RNA was detected by Northern analysis. Ocular pathology was assessed by conventional histology, immunostaining for gp120 envelope protein, and in situ apoptosis detection with end-labelling. RESULTS: Abnormalities of lens epithelial cell development were detected as early as embryonic day 14.5. Histological changes included the malformation of an embryonal lens nucleus and poor closure of the lens suture lines. This resulted in congenital nuclear cataracts, as occur in congenital viral infections in human patients. In the adult animals, lenses were notable for extensive vacuolation, liquefaction, and degeneration of the cortex. Mild iridocyclitis and vitritis were also noted in adult transgenic mice. Immunostaining demonstrated the expression of gp 120 envelope protein within the lens epithelial and fibre cells. End-labelling with terminal deoxyribonucleotidyl transferase showed increased numbers of apoptotic cells in the adult lens. CONCLUSIONS: These findings suggest that one or more HIV-1 proteins are associated with congenital nuclear cataract formation and uveitis in HIV-transgenic mice.

Animals↗
PubMed2001

Enzyme replacement therapy in Fabry disease: a randomized controlled trial.

CONTEXT: Fabry disease is a metabolic disorder without a specific treatment, caused by a deficiency of the lysosomal enzyme alpha-galactosidase A (alpha-gal A). Most patients experience debilitating neuropathic pain and premature mortality because of renal failure, cardiovascular disease, or cerebrovascular disease. OBJECTIVE: To evaluate the safety and efficacy of intravenous alpha-gal A for Fabry disease. DESIGN AND SETTING: Double-blind placebo-controlled trial conducted from December 1998 to August 1999 at the Clinical Research Center of the National Institutes of Health. PATIENTS: Twenty-six hemizygous male patients, aged 18 years or older, with Fabry disease that was confirmed by alpha-gal A assay. INTERVENTION: A dosage of 0.2 mg/kg of alpha-gal A, administered intravenously every other week (12 doses total). MAIN OUTCOME MEASURE: Effect of therapy on neuropathic pain while without neuropathic pain medications measured by question 3 of the Brief Pain Inventory (BPI). RESULTS: Mean (SE) BPI neuropathic pain severity score declined from 6.2 (0.46) to 4.3 (0.73) in patients treated with alpha-gal A vs no significant change in the placebo group (P =.02). Pain-related quality of life declined from 3.2 (0.55) to 2.1 (0.56) for patients receiving alpha-gal A vs 4.8 (0.59) to 4.2 (0.74) for placebo (P =.05). In the kidney, glomeruli with mesangial widening decreased by a mean of 12.5% for patients receiving alpha-gal vs a 16.5% increase for placebo (P =.01). Mean inulin clearance decreased by 6.2 mL/min for patients receiving alpha-gal A vs 19.5 mL/min for placebo (P =.19). Mean creatinine clearance increased by 2.1 mL/min (0.4 mL/s) for patients receiving alpha-gal A vs a decrease of 16.1 mL/min (0.3 mL/s) for placebo (P =.02). In patients treated with alpha-gal A, there was an approximately 50% reduction in plasma glycosphingolipid levels, a significant improvement in cardiac conduction, and a significant increase in body weight. CONCLUSION: Intravenous infusions of alpha-gal A are safe and have widespread therapeutic efficacy in Fabry disease.

Adult↗
PubMed2001

Lsh, a SNF2 family member, is required for normal murine development.

Lsh is a member of the SNF2 family of chromatin remodelers, that regulate diverse biological processes such as replication, repair and transcription. Although expression of Lsh is highly tissue specific in adult animals, Lsh mRNA is detectable in multiple tissues during embryogenesis. In order to determine the physiologic role of Lsh during murine development and to assess its unique function in adult mice, we performed targeted deletion of the Lsh gene using homologous recombination in murine embryonic stem cells. Lsh-/- embryos occurred with the expected Mendelian frequency after implantation and during embryogenesis. However, Lsh-/- mice died within a few hours after birth. Furthermore, newborn mice were 22% lower in weight in comparison with their littermates and showed renal lesions. Thus Lsh is a non-redundant member of the SNF2 family and is essential for normal murine development and survival.

Animals↗
PubMed2001

Apoptosis in podocytes induced by TGF-beta and Smad7.

Primary and secondary forms of focal segmental glomerulosclerosis (FSGS) are characterized by depletion of podocytes and constitute a central manifestation of chronic progressive glomerular diseases. Here we report that podocytes undergo apoptosis at early stages in the course of progressive glomerulosclerosis in TGF-beta1 transgenic mice. Apoptosis is associated with progressive depletion of podocytes and precedes mesangial expansion. Smad7 protein expression is strongly induced specifically in damaged podocytes of transgenic mice and in cultured murine podocytes treated with TGF-beta. TGF-beta1 and Smad7 each induce apoptosis in podocytes, and their coexpression has an additive effect. Activation of p38 MAP kinase and caspase-3 is required for TGF-beta-mediated apoptosis, but not for apoptosis induced by Smad7. Unlike TGF-beta, Smad7 inhibits nuclear translocation and transcriptional activity of the cell survival factor NF-kappaB. Our results suggest a novel functional role for Smad7 as amplifier of TGF-beta-induced apoptosis in podocytes and a new pathomechanism for podocyte depletion in progressive glomerulosclerosis.

Animals↗
PubMed2000

Glucocorticoids suppress human immunodeficiency virus type-1 long terminal repeat activity in a cell type-specific, glucocorticoid receptor-mediated fashion: direct protective effects at variance with clinical phenomenology.

Glucocorticoid administration and/or excess secretion have been associated with increased Human Immunodeficiency Virus Type-1 (HIV-1) replication and AIDS progression. The HIV-1 long terminal repeat (LTR) promoter contains glucocorticoid-responsive element (GRE)-like sequences that could mediate a positive effect of glucocorticoids on HIV-1. In addition, we recently demonstrated that the HIV-1 accessory protein Vpr is a potent coactivator of the glucocorticoid receptor, which, like the host coactivator p300, potentiates the effect of glucocorticoids on GRE-containing, glucocorticoid-responsive genes. Such an effect may increase the sensitivity of several host target tissues to glucocorticoids by several fold, and may, thus, contribute to a positive effect of glucocorticoids on the HIV-1-LTR in infected host cells. In this study, we determined the direct effect of glucocorticoids on HIV-1-LTR by examining the ability of dexamethasone to modulate the activity of this promoter coupled to the luciferase reporter gene in human cell lines. Dexamethasone markedly inhibited Tat-stimulated, p300- or Vpr-enhanced luciferase activities in a cell-type specific, dose-dependent, and glucocorticoid receptor-mediated fashion. This effect of dexamethasone was not potentiated by Vpr, was antagonized by the glucocorticoid receptor antagonist RU 486 and required the DNA-binding domain of the receptor. These data suggest that the inhibitory effect of glucocorticoids on the HIV-1-LTR may be exerted via non-GRE-dependent inhibition of the strongly positive host transcription factor NF-kappaB, which interacts with the DNA- and ligand-binding domains of the receptor. Alternatively, it is also possible that dexamethasone-activated glucocorticoid receptor competes with other transcription factors for their binding sites on the promoter region or squelches transcription factors shared by HIV-1-LTR and glucocorticoid-responsive promoters. We conclude that glucocorticoids suppress, rather than stimulate, the HIV-1 promoter, thus acting, protectively for the host. Their apparent negative clinical association with AIDS is most likely due to immunosuppression of the host.

Animals↗
PubMed2000

Identification of renox, an NAD(P)H oxidase in kidney.

Oxygen sensing is essential for homeostasis in all aerobic organisms, but its mechanism is poorly understood. Data suggest that a phagocytic-like NAD(P)H oxidase producing reactive oxygen species serves as a primary sensor for oxygen. We have characterized a source of superoxide anions in the kidney that we refer to as a renal NAD(P)H oxidase or Renox. Renox is homologous to gp91(phox) (91-kDa subunit of the phagocyte oxidase), the electron-transporting subunit of phagocytic NADPH oxidase, and contains all of the structural motifs considered essential for binding of heme, flavin, and nucleotide. In situ RNA hybridization revealed that renox is highly expressed at the site of erythropoietin production in the renal cortex, showing the greatest accumulation of renox mRNA in proximal convoluted tubule epithelial cells. NIH 3T3 fibroblasts overexpressing transfected Renox show increased production of superoxide and develop signs of cellular senescence. Our data suggest that Renox, as a renal source of reactive oxygen species, is a likely candidate for the oxygen sensor function regulating oxygen-dependent gene expression and may also have a role in the development of inflammatory processes in the kidney.

Amino Acid Sequence↗
PubMed2000

Reduced hematopoietic function and enhanced radiosensitivity of transforming growth factor-beta1 transgenic mice.

The cytokine transforming growth factor-beta1 (TGF-beta1) has been implicated in some tissue responses to radiation. Previous studies have demonstrated that exogenous TGF-beta1 increased the lethality of radiation in mice, but the effects of endogenous TGF-beta1 have not been investigated. To this end, we examined mice that are transgenic for active TGF-beta1 (Alb/TGF-beta1), over-expressed via an albumin promoter in the liver with resultant elevation of circulating levels of this cytokine. Alb/TGF-beta1 mice subjected to 8 Gy of total body irradiation at 3 or 5 weeks of age experienced significantly higher mortality than wild type age- and sex-matched controls by 1 to 2 weeks after irradiation. Alb/TGF-beta1 3 weeks of age also succumbed to 2 and 4 Gy of whole-body irradiation, while no mortality was observed in wild type mice. Four-week-old Alb/TGF-beta1 mice exhibited mild anemia and mild uremia. At one week after whole body irradiation with 2 Gy, 4-week-old Alb/TGF-beta1 mice had significantly reduced white blood cell counts, hematocrit, and platelet counts. Histopathologically, irradiated Alb/TGF-beta1 mice exhibited decreased bone marrow cellularity and decreased splenic extramedullary hematopoiesis. These results suggest that chronic over-expression of active TGF-beta1 is associated with increased radiosensitivity and that this effect may be mediated by increased sensitivity of bone marrow to the suppressive effects of radiation. Since TGF-beta1 levels can be greatly elevated in patients with certain tumors, these findings may be significant for radiotherapy. Int. J. Cancer (Radiat. Oncol. Invest.) 90, 13-21 (2000). Published 2000 Wiley-Liss, Inc.

Age Factors↗
PubMed2000

Fluoxetine versus sertraline and paroxetine in major depression: tolerability and efficacy in anxious depression.

BACKGROUND: Major depression with high levels of anxiety (anxious depression) is a common subtype of depression associated with greater psychosocial impairment and poorer response to antidepressant treatment. It is unclear whether in this population there are differences in efficacy or tolerability across selective serotonin reuptake inhibitors. For this reason, using head-to-head acute treatment comparison, we compared efficacy and tolerability of fluoxetine, sertraline, and paroxetine among depressed patients with high levels of anxiety. METHODS: Patients (N = 108) with DSM-IV major depression and high levels of anxiety (a HAM-D-Anxiety/Somatization Factor score > or =7) were randomized to fluoxetine, sertraline, or paroxetine treatment in a double-blind fashion. Changes in overall depression and anxiety were assessed. RESULTS: Patients demonstrated similar baseline-to-endpoint improvement in HAM-D-17 and HAM-D-Anxiety/Somatization Factor scores. Patients also demonstrated similar change-over-time improvement in HAM-D-17 and HAM-D-Anxiety/Somatization Factor scores, except at week one where fluoxetine- and sertraline-treated patients had statistically significantly greater improvement than paroxetine-treated patients in the HAM-D-Anxiety/Somatization Factor score. There were no significant differences across treatments in percentages of patients with substantial emergence, any worsening, or improvement at endpoint in individual HAM-D Items 9 (agitation), 10 (psychic anxiety), and 11 (somatic anxiety). Overall, all treatments were well tolerated. CONCLUSION: These data showed no significant differences in efficacy and tolerability of fluoxetine, sertraline, and paroxetine in patients with high levels of baseline anxiety symptoms during the acute treatment of major depression. Each treatment was similarly effective in improving depression in this subtype of patients with anxious depression.

Adult↗
PubMed2000

Parvovirus B19 DNA in kidney tissue of patients with focal segmental glomerulosclerosis.

Focal segmental glomerulosclerosis (FSGS) represents a clinicopathological syndrome with diverse causes. We examined the possibility that some cases of FSGS are associated with parvovirus B19 infection. We studied renal biopsy tissue from 40 patients, including those with idiopathic FSGS, collapsing FSGS, membranous nephropathy, and minimal change disease, as well as normal renal tissue removed at the time of nephrectomy from 4 patients. DNA was extracted from frozen blocks of kidney tissue and amplified using nested polymerase chain reaction. Parvovirus B19 DNA was amplified from 8 of 10 patients with idiopathic FSGS, 9 of 10 patients with collapsing FSGS, 6 of 10 patients with membranous nephropathy, 5 of 10 patients with minimal change disease, and 2 of 4 cancer nephrectomy samples. The prevalence of parvovirus B19 DNA was greater among patients with idiopathic FSGS and collapsing FSGS compared with patients with other diagnoses (P = 0.05). In situ hybridization studies using digoxigenin-labeled DNA probes failed to detect parvovirus B19 nucleic acid in any of the kidney tissue samples. These results suggest that parvovirus B19 DNA is commonly found in the kidneys of patients with a range of renal diagnoses, possibly representing latent DNA from past infection. The failure to localize parvovirus B19 nucleic acid within kidney argues against ongoing, high-level viral replication. Nevertheless, the increased prevalence of B19 DNA in patients with idiopathic FSGS and collapsing FSGS could indicate a pathogenic role for the virus in the cause of FSGS in certain patients.

Biopsy↗
PubMed2000

Role of T lymphocytes in renal disease in HIV-transgenic mice.

The pathogenesis of human immunodeficiency virus (HIV)-associated focal segmental glomerulosclerosis (FSGS) has remained obscure. It has been proposed that renal parenchymal cells may be infected with HIV-1. If such infection occurs, the target cells would be expected to express viral proteins and thus could be targets for cytotoxic T lymphocytes. We previously described mice transgenic for a gag-pol-deleted HIV-1 genome that developed FSGS. In the present study, we tested the requirement for functional T cells in the evolution of renal disease in this model. We bred the HIV-transgenic mice (T26) with athymic nude mice to produce athymic T26 mice. We confirmed by flow cytometry of peripheral blood, thymus, lymph node, and spleen that the athymic T26 mice lacked mature T cells. The athymic T26 mice developed renal disease characterized by FSGS, tubular atrophy and dilatation, and interstitial infiltrate that was qualitatively identical to that seen in the parental T26 mice. Quantitative assessment of the athymic T26 mouse kidneys showed that glomerulosclerosis, tubular injury, and interstitial infiltrate were less severe compared with the parental T26 mouse kidneys. Although T26 mouse kidneys had a mixed cellular infiltrate composed of CD4 cells, CD8 cells, and macrophages, interstitial infiltrates within the athymic T26 mouse kidneys included macrophages but lacked both CD4 and CD8 cells. The renal expression of the HIV transgene was 1. 7-fold greater in T26 mice compared with athymic T26 mice. We conclude that mature T cells are not absolutely required for the development of HIV-associated nephropathy in transgenic mice but that, in their absence, renal disease is significantly milder. These data suggest that T-cell-mediated cytotoxicity directed against renal cells expressing virally encoded proteins is not an essential feature of renal pathogenesis in this model.

Animals↗
PubMed2000

Glomerulosclerosis and viral gene expression in HIV-transgenic mice: role of nef.

BACKGROUND: Human immunodeficiency virus (HIV)-associated nephropathy is characterized by focal segmental glomerulosclerosis and microcystic tubular dilation. We have previously described a mouse transgenic for a Deltagag-pol HIV-1 genome, which develops glomerulosclerosis, cutaneous papillomas, and cataracts. METHODS: We developed mice transgenic for a Deltagag-pol-nef HIV genome in order to investigate the role of the nef gene in these phenotypes. RESULTS: One transgenic line, X5, expressed HIV mRNA in kidney and consistently manifested focal segmental glomerulosclerosis and tubular dilation by six weeks of age. Northern analysis indicated that renal transgene expression was higher in the Deltagag-pol-nef mice compared with the Deltagag-pol mice. In situ hybridization and immunostaining demonstrated HIV RNA and protein expression within the glomerular epithelial cells and tubular epithelial cells. These cell types showed histologic evidence of toxicity, including vacuolation and detachment from basement membrane, and exhibited increased rates of apoptosis. These data suggest that the renal disease seen in the Deltagag-pol-nef transgenic mouse may be caused by the expression of HIV genes within renal epithelial cells, that this expression may induce cellular toxicity, including apoptosis, and that nef is not required for the induction of renal disease. We have previously described mice bearing the nef gene, which do not manifest renal disease. In further experiments, Deltagag-pol-nef mice were bred with nef mice; these dual-transgenic mice developed renal disease that generally resembled that seen in Deltagag-pol-nef mice, but with somewhat more severe glomerulosclerosis and less severe tubulointerstitial injury. RESULTS: The results of these transgenic studies suggest that the role of nef is complex and may act both to reduce transgene expression and to potentiate glomerular injury induced by other HIV-1 gene products.

AIDS-Associated Nephropathy↗
PubMed2000

Changes in energy during treatment of depression: an analysis of fluoxetine in double-blind, placebo-controlled trials.

More than two thirds of patients with depression present with symptoms of fatigue, low energy, and listlessness. Because daytime sedation may be a concern in such patients, a "nonsedating" antidepressant should be considered. The authors examined the effects of fluoxetine on depression-related disturbances in energy. Data from seven double-blind, placebo-controlled clinical trials in 2,075 patients with major depression were retrospectively analyzed. The Hamilton Rating Scale for Depression (HAM-D) Retardation factor score (total of items 1, 7, 8, and 14) was used as the primary measure of energy improvement, whereas the HAM-D-17 total score was used to assess changes in overall depression. Elderly patients (aged 60 years and older) were included in the overall group and were also analyzed separately. In addition, a subgroup analysis was performed using the HAM-D Retardation factor score to categorize patients as having low (score < 8) or high (score > or = 8) levels of retardation at baseline. Beginning at week 3, fluoxetine-treated patients experienced statistically significant reductions in their HAM-D Retardation factor score compared with placebo-treated patients. The reductions for the elderly subgroup were less than those for the overall population, but they were still statistically significant beginning at week 4. Patients in both the low and high baseline retardation groups improved significantly. HAM-D-17 total scores for fluoxetine-treated patients in all groups (total, elderly, high retardation, and low retardation) improved significantly compared with placebo-treated patients. These findings demonstrate that fluoxetine-treated patients experience an improvement in energy symptoms as their overall depression improves.

Adult↗
PubMed2000

Detection of indinavir crystals in urine: dependence on method of analysis.

OBJECTIVES: To determine the frequency of crystalluria in patients treated with the human immunodeficiency virus protease inhibitor indinavir and to compare methods of detecting crystalluria. METHODS: A total of 308 freshly voided urine specimens from 168 patients treated with indinavir were evaluated by manual microscopy of sediment and microscopy with an automated workstation and by dipstick analysis. RESULTS: Crystals were detected in 22%, 31%, or 32% of specimens using, respectively, an automated workstation, manual microscopy, or both methods. Proteinuria or hemoglobinuria occurred significantly more often in specimens with (28%) than without (18%) crystals. Frequency of crystalluria was unrelated to specific gravity, but it increased at higher pH. Crystals were detected in 21% of specimens with pH less than 6 and 42% of specimens with pH of 6 or higher. CONCLUSIONS: Crystalluria occurs in more than 30% of urine specimens from patients treated with indinavir, but detection rates vary substantially with method of analysis. Manual microscopy detected crystalluria 41% more often than did an automated workstation.

Crystallization↗
PubMed1999

Isoform specificity of commercially-available anti-TGF-beta antibodies.

The transforming growth factor-beta (TGF-beta) cytokine family has important and complex effects on many biologic processes. Mammals have three TGF-beta isoforms which differ in their primary amino acid sequence, receptor binding characteristics, distribution, and function. Characterization of TGF-beta production and localization is critically dependent upon appropriate reagents, including antibodies. We have analyzed the isoform specificity of eight commercially-available TGF-beta antibodies, including one monoclonal antibody and seven polyclonal antibodies. We carried out semi-quantitative Western blot analysis using recombinant TGF-beta1, beta2, and beta3 as targets. We found that sensitivity and isoform specificity are dependent in part upon the presence or absence of reducing conditions. The antibodies tested showed a broad range of sensitivity, with an ability to detect 50 pg to 20 ng. Cross-reactivity with another, incorrect isoform was seen with several antibodies, and ranged from 0.2% to 42%. Nevertheless, we identified TGF-beta antibodies directed against each isoform which provide moderate-to-high sensitivity and specificity when used in Western blot analysis. These results may have relevance for investigators who wish to detect particular TGF-beta isoforms with techniques other than Western blot analysis, particularly when these techniques involve denatured proteins.

Animals↗
PubMed1999

The HIV-1 virion-associated protein vpr is a coactivator of the human glucocorticoid receptor.

The HIV-1 virion-associated accessory protein Vpr affects both viral replication and cellular transcription, proliferation, and differentiation. We report that Vpr enhances the activity of glucocorticoids in lymphoid and muscle-derived cell lines by interacting directly with the glucocorticoid receptor and general transcription factors, acting as a coactivator. Vpr contains the signature motif LXXLL also present in cellular nuclear receptor coactivators, such as steroid receptor coactivator 1 and p300/CREB-binding protein, which mediates their interaction with the glucocorticoid and other nuclear hormone receptors. A mutant Vpr molecule with disruption of this coactivator signature motif lost its ability to influence transcription of glucocorticoid-responsive genes and became a dominant-negative inhibitor of Vpr, possibly by retaining its general transcription factor-binding activities. The glucocorticoid coactivator activity of Vpr may contribute to increased tissue glucocorticoid sensitivity in the absence of hypercortisolism and to the pathogenesis of AIDS.

Cell Line↗
PubMed1999

TGF-beta and fibrosis.

Transforming growth factor-beta (TGF-beta) isoforms are multifunctional cytokines that play a central role in wound healing and in tissue repair. TGF-beta is found in all tissues, but is particularly abundant in bone, lung, kidney and placental tissue. TGF-beta is produced by many but not all parenchymal cell types, and is also produced or released by infiltrating cells such as lymphocytes, monocytes/macrophages, and platelets. Following wounding or inflammation, all these cells are potential sources of TGF-beta. In general, the release and activation of TGF-beta stimulates the production of various extracellular matrix proteins and inhibits the degradation of these matrix proteins, although exceptions to these principles abound. These actions of TGF-beta contribute to tissue repair, which under ideal circumstances leads to the restoration of normal tissue architecture and may involve a component of tissue fibrosis. In many diseases, excessive TGF-beta contributes to a pathologic excess of tissue fibrosis that compromises normal organ function, a topic that has been the subject of numerous reviews [1-3]. In the following chapter, we will discuss the role of TGF-beta in tissue fibrosis, with particular emphasis on renal fibrosis.

Animals↗