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Biomedical subjects

J Mattana

Publications and source records attributed to J Mattana.

At least 19 recordsLinked to original sources
PubMed2003

Thrombotic thrombocytopenic purpura: a rare cause of thrombocytopenia in HIV-infected hemophiliacs.

Thrombocytopenia is a common complication in human immunodeficiency virus (HIV)-infected hemophiliacs. The etiology is multifactorial and a majority of the patients with hemophilia exhibit a decreased platelet count within 10 years of seroconversion. Thrombocytopenia in these patients is associated with a high risk of bleeding and death. Thrombotic microangiopathy causing thrombocytopenia in HIV-infected hemophiliacs is extremely rare. We describe an HIV-infected hemophilic patient who presented with bleeding, renal insufficiency, and thrombocytopenia. Platelet transfusion resulted in deterioration of clinical condition. Examination of blood smears demonstrated a microangiopathic process. The patient responded well to plasmapheresis with normalization of platelet and renal function. Thrombotic thrombocytopenic purpura should be suspected in HIV-infected hemophiliacs who present with a new onset of thrombocytopenia and anemia as delay in treatment may result in fatal sequelae.

Adult↗
PubMed2001

Interstitial pneumonitis in a patient treated with alpha-interferon and ribavirin for hepatitis C infection.

Hepatitis C is a common infection with worldwide prevalence. It has a variable course and can lead to chronic hepatitis, cirrhosis and hepatocellular carcinoma. Until recently alpha-interferon (IFN-alpha) was the only effective treatment available. Combination therapy with IFN-alpha and ribavirin has been found to be more efficacious than IFN-alpha alone. Various side effects have been ascribed to interferon, such as arthralgias, myalgias, fatigue, and gastrointestinal and neuropsychiatric symptoms. Interstitial pneumonitis is a rare but known complication of IFN-alpha when given at a high dosage of 6 to 10 million units per day. Ribavirin is associated with dose-dependent hemolytic anemia, cough, dyspnea, rash, depression, and dyspepsia, although a potential role in interferon-induced interstitial pneumonitis has not been described. We describe a patient with an excellent clinical response of chronic hepatitis C to combination therapy with IFN-alpha at a dosage of 3 million units per day and ribavirin. The patient developed interstitial pneumonitis that resolved after discontinuation of IFN-alpha and ribavirin. Given that interstitial pneumonitis has previously been reported with high-dose IFN-alpha, this case suggests that this complication may occur with lower dosages of IFN-alpha, although a potential role for ribavirin in this disorder at present remains speculative.

Antiviral Agents↗
PubMed2000

Morphine stimulates mesangial cell TNF-alpha and nitrite production.

BACKGROUND: Intravenous opiate abusers are susceptible to develop heroin and HIV-associated nephropathies; however, the role of opiates in the development of these kidney lesions is not clear. Patients with opiate addiction are prone to recurrent infections. METHODS: The effect of morphine was studied on the generation of TNF-alpha with or without LPS (lipopolysaccharide) by cultured mouse mesangial cells. In addition, the effect of morphine was evaluated on mesangial cell nitrite production. To evaluate the role of opiate receptors, we studied the effect of naloxone and naltrexone on mesangial cell TNF-alpha and nitrite production. To determine the role of TNF-alpha on mesangial cell nitrite production, we examined the effect of anti-TNF-alpha antibody on morphine-induced nitrite production. Assay of TNF-alpha and nitrite production was carried by ELISA and Griess method respectively. RESULTS: Morphine alone did not enhance the generation of TNF-alpha by mesangial cells, however, an enhanced (P < 0.001) TNF-alpha production was observed when mesangial cells were first treated with morphine for 18 h and then activated further with LPS. Maximum release of TNF-alpha was seen at a concentration of 10(-12) M of morphine. Opiate receptor antagonists (naloxone and naltrexone) inhibited the effect of morphine. Morphine also amplified (P < 0.0002) the effect of LPS on mesangial cell nitrite production. Anti-TNF-alpha antibody attenuated morphine induced nitrite generation. CONCLUSION: We conclude that morphine stimulates the generation of TNF-infinity by LPS-activated mesangial cells. This effect of morphine seems to be opiate receptor mediated and has a downstream effect in the form of mesangial cell nitrite generation. The present in vitro study provides the basis for a hypothesis that morphine may be playing a role in the development of heroin and HIV-associated nephropathies.

Animals↗
PubMed1999

Oxidation of extracellular matrix modulates susceptibility to degradation by the mesangial matrix metalloproteinase-2.

Protein oxidation occurs in aging and in various inflammatory conditions. Glomerulosclerosis is characterized by an accumulation of extracellular matrix (ECM) proteins and a paucity of glomerular mesangial cells and can be seen as an end-result of glomerular injury and in aging. ECM accumulation is the net result of the balance between synthesis and degradation. ECM may become oxidized as a part of inflammatory renal injury and with aging. We evaluated the hypothesis that oxidation of mesangial ECM could alter its susceptibility to the action of ECM degrading enzymes. Radiolabeled mesangial ECM was generated by growing cells on tissue culture plastic and incubating with [3H]proline. After removal of cells, leaving behind ECM, selected wells were oxidized using a FeCl3/EDTA/ascorbate system or treated under control conditions. The control and oxidized matrices were then incubated with concentrated supernatants from mesangial cells containing the major mesangial ECM degrading enzyme, the matrix metalloproteinase-2, whose activity was confirmed by gelatin substrate zymography. Counts released corresponding with ECM degraded were measured. ECM oxidized with this system was significantly less susceptible to degradation compared to control ECM. To confirm that this effect was specifically due to oxidative modification of the ECM rather than changes unrelated to oxidation we coincubated ECM with the oxidizing system plus the radical spin trap N-tert-butyl-alpha-phenylnitrone (PBN). PBN treatment was able to prevent the impaired susceptibility to degradation induced by exposure to the oxidizing system. Exposure of ECM to milder oxidative stress, however, modestly enhanced susceptibility to degradation. These data suggest that oxidation of mesangial ECM can modulate its susceptibility to degradation. This may account for the development of ECM accumulation and glomerulosclerosis in inflammatory renal injury and in aging.

Analysis of Variance↗
PubMed1999

Absence of age-related increase in systolic blood pressure in ambulatory patients with HIV infection.

BACKGROUND: Systolic blood pressure is well known to increase significantly with age and is strongly correlated with stroke and coronary artery disease. We and other investigators have reported a low prevalence of hypertension in subgroups of patients with HIV infection. In the present study, we examined an ambulatory population of patients with HIV infection to determine whether in the outpatient setting they may lack an age-related increase in systolic blood pressure. METHODS: In an ambulatory outpatient practice, medical records of 178 consecutive patients with HIV infection and those of 200 control subjects were examined. Systolic and diastolic blood pressure and other clinical and laboratory variables were recorded. Scatter plots were generated to compare age with systolic blood pressure. Spearman rank correlation analysis was carried out to determine the relationship between systolic blood pressure and age and other variables. RESULTS: Patients ranged in age from 13 to 69 years. There was only a very slight increase (which did not achieve statistical significance) in systolic blood pressure with aging in the patients with HIV infection, in contrast to the control population, in which an age-related increase in systolic blood pressure was seen that was comparable to published Framingham data. Mean systolic blood pressure for the group as a whole was 118.2 +/- 1.1 mm Hg. Mean serum albumin was 4.2 +/- 0.04 g/dL and was only slightly diminished in older patients. Mean serum cholesterol was 176.8 +/- 3.4 mg/dL and this bore no relationship to aging. More advanced stages of HIV infection also did not correlate with the lack of age-associated systolic hypertension. CONCLUSION: The present population of ambulatory patients infected with HIV seem to lack an age-related increase in systolic blood pressure; this may be caused by such variables as autonomic dysfunction or factors that may attenuate the development of atherosclerosis.

Adolescent↗
PubMed1998

Metal-catalyzed oxidation of immunoglobulin G impairs Fc receptor-mediated binding to macrophages.

Enhanced oxidative stress is a feature of inflammatory and infectious conditions. Proteins may be important targets of oxidation and this may alter their function. We evaluated whether metal-catalyzed oxidation of IgG could alter its ability to bind to Fc receptors on macrophages. Human IgG incubated with an FeCl3/EDTA/ascorbate metal-catalyzed oxidation system resulted in a significant increase in carbonyl content, a measure of protein oxidation, compared to IgG treated with EDTA alone (control). Western blot analysis using an antibody to oxidized protein revealed an increase in antibody binding to both the heavy (Fc portion-containing) and light chains of IgG treated with the oxidizing system. Western blot analysis of papain-digested IgG confirmed oxidative modification of the Fc portion. Binding studies carried out with J774.16 macrophages demonstrated significantly diminished ability of the oxidized IgG to bind to macrophage Fc receptors compared to control IgG. These data demonstrate that IgG is susceptible to metal-catalyzed oxidation and that this impairs its ability to bind to macrophage Fc receptors. Oxidation of IgG might play a role in modulating immune function in infection and disorders associated with immune complex formation by diminishing IgG binding to phagocytic cells.

Ascorbic Acid↗
PubMed1998

Outcome of stroke in patients undergoing hemodialysis.

BACKGROUND: While elevated levels of serum creatinine have been shown to be a risk factor for diminished survival after stroke, it is unknown how renal replacement therapy may affect the outcome. METHODS: Strokes occurring in 26 consecutive patients undergoing hemodialysis at our institution were reviewed and clinical and laboratory variables and outcome were compared with those of patients who had a stroke but had normal renal function. RESULTS: Twenty-four strokes in the patients undergoing hemodialysis were ischemic while only 2 were hemorrhagic. Virtually all the patients had hypertension, half had diabetes mellitus, and most had some prior evidence of cardiovascular disease at the time of their stroke. Fifty percent of the patients undergoing hemodialysis had a good outcome (defined as being discharged home) while the remainder had a poor outcome (defined as dying or being discharged to a nursing facility). The combined presence of hypertension and coronary artery disease had a sensitivity of 91.2% for identifying patients with a poor outcome, while male sex, the presence of coronary artery disease, and the combined presence of hypertension, coronary artery disease, and/or congestive heart failure had sensitivities greater than 80% but low specificity. The outcome of patients undergoing hemodialysis was comparable with that of a control group of patients who had a stroke but had normal renal function, although the length of hospital stay was greater (mean [+/-SEM] 29.8+/-6.4 days vs 12.7+/-1.1 days, respectively; P<.01). CONCLUSIONS: Hospitalized patients undergoing hemodialysis in whom stroke occurs appear to have as good an outcome as that of patients with normal renal function, although they are hospitalized longer. In addition, certain clinical variables seem to be associated with a worse outcome. Aggressive measures to prevent and treat stroke seem as warranted for patients undergoing hemodialysis as for patients with normal renal function, although interventions to reduce the length of hospital stay are needed.

Adult↗
PubMed1998

Extracellular matrix modulates mesangial cell apoptosis and mRNA expression of cathepsin-B and tissue transglutaminase.

Mesangial matrix is a dynamic structure which modulates mesangial cell function. Since accumulation of matrix precedes the development of focal glomerulosclerosis, we studied the effect of different matrices on mesangial cell (MC) apoptosis. Suspended mesangial cells became apoptotic in a time dependent manner. Collagen type III did not modulate MC apoptosis when compared to cells grown on plastic. MCs grown on Matrigel, collagen type I and IV showed an increased number of apoptotic cells when compared to MCs grown on plastic. DNA end-labeling further confirmed these observations. MCs grown on Matrigel showed enhanced (P < 0.05) mRNA expression for tissue transglutaminase (TTG) and cathepsin-B. Mesangial cells grown on Matrigel also showed enhanced expression of superoxide dismutase (SOD). We conclude that mesangial cells require attachment to the matrix for their survival and alteration of the quality of matrix modulates mesangial cell apoptosis.

Animals↗
PubMed1998

Oxidation of the mesangial matrix metalloproteinase-2 impairs gelatinolytic activity.

Glomerulosclerosis is characterized by an accumulation of mesangial extracellular matrix. Oxygen radicals are strongly implicated in glomerular injury but it is unclear by what mechanism they could modulate matrix turnover dynamics. We evaluated whether oxidation of the 72 kD mesangial matrix metalloproteinase-2 (MMP-2), the major mesangial matrix-degrading enzyme, could alter its gelatinolytic activity. Oxidation of the MMP-2 using a FeCl3/ascorbate system resulted in impaired ability to degrade [3H]gelatin compared to control. Samples were also subjected to SDS-PAGE gelatin substrate zymography. At the 72 kD position a significant impairment of gelatinolytic activity of oxidized samples was observed, a decrease attenuated by coincubation of samples with the FeCl3/ascorbate system plus the radical spin trap N-tert-butyl-alpha-phenylnitrone suggesting specificity of oxidative changes in the decrease in enzymatic activity. These data represent the first report demonstrating that oxidation of the MMP-2 diminishes its activity and suggest a previously undescribed mechanism by which oxygen radicals may contribute to altered turnover of extracellular matrix.

Animals↗
PubMed1998

Metal-catalyzed oxidation of extracellular matrix increases macrophage nitric oxide generation.

BACKGROUND: Oxygen radicals are believed to play a significant role in glomerular disease. In part this may be due to oxidation of lipids, but protein oxidation may play a contributory role as well. We have demonstrated that the mesangial extracellular matrix is susceptible to metal-catalyzed oxidation and that this increases scavenger receptor-mediated adhesion of macrophages, cells which appear to be important participants in glomerular injury via their secretory products. As other scavenger receptor ligands can increase macrophage nitric oxide generation, we examined whether oxidation of matrix could increase the activity of macrophage inducible nitric oxide synthase (iNOS). METHODS: Extracellular matrix was oxidized using a metal-catalyzed oxidation system. Matrix oxidation was measured using carbonyl analysis, and iNOS activity in macrophages seeded onto the matrix was measured by nitrite determination and Western and Northern analyses for iNOS. RESULTS: Macrophages exposed to oxidized matrix demonstrated a significant enhancement of iNOS activity. This enhancement could be antagonized by cotreatment of matrix with the radical spin trap N-tert-butyl-a-phenylnitrone, resulting in a corresponding decrease in protein carbonyl content, a measure of protein oxidation. Seeding macrophages onto oxidized matrix and adding the scavenger receptor ligand polyinosinic acid further augmented iNOS activity, suggesting that additional scavenger receptors were available to bind ligand and that further augmentation of iNOS activity did not require an additional change in cell shape. Western blot analysis revealed an increase in iNOS protein expression as a consequence of interaction with the oxidized matrix, but there was no difference in iNOS mRNA expression by Northern analysis suggesting a post-transcriptional mechanism for enhanced iNOS activity. CONCLUSION: These data demonstrate that oxidation of extracellular matrix enhances macrophage nitric oxide generation, and suggest a previously undescribed role for extracellular matrix modification in the regulation of cellular function and possibly the mediation of glomerular injury.

Animals↗
PubMed1998

Simulated glomerular hypertension promotes mesangial cell apoptosis and expression of cathepsin-B and SGP-2.

BACKGROUND: Focal glomerulosclerosis (FGS) is characterized by the accumulation of mesangial matrix and lack of mesangial cells (MC). We studied the role of glomerular hypertension (GH) in the development of MC hypoplasia. METHODS: We used an in vitro model of GH to study the effect of GH on MC apoptosis. Cultured rat endothelial cells were grown in the intracapillary space and MCs were grown in the extracapillary space. MC proliferation as well as apoptosis was evaluated under simulated normal glomerular pressure (SNGP) as well as simulated glomerular hypertension (SGH). Apoptosis was determined morphologically by DNA fragmentation using Hoechst staining as well as with the use of DNA gel electrophoresis. MCs grown under SNGP and SGH were also evaluated for the expression of genes associated with active cell death. In addition, we evaluated the effect of direct applied pressure on MC apoptosis. RESULTS: MCs grown under SGH were less elliptical and had a tendency to develop a dome in the center. Direct applied pressure promoted MC apoptosis in a dose and time dependent manner. DNA gel electrophoresis from MCs grown under SGH also showed integer multiples of 180 base pairs (ladder pattern); whereas cells grown under SNGP showed no DNA fragmentation. SGH increased mRNA expression of cathepsin-B (SNGP, 0.31 +/- 0.04 vs SGH, 0.57 +/- 0.03, P < 0.01, n = 3) and SGP-2 (SNGP, 0.55 +/- 0.05 vs SHG, 1.08 +/- 0.12, P < 0.01, n = 3) in MCs when compared to cells grown under SNGP. CONCLUSIONS: The present in vitro study suggests that GH has the potential to convert a hypercellular mesangium into a hypocellular one. This effect of GH is associated with expression of genes associated with active cell death.

Animals↗
PubMed1997

Metal-catalyzed oxidation of extracellular matrix proteins disrupts integrin-mediated adhesion of mesangial cells.

We undertook the present study to determine whether oxidation of extracellular matrix could alter RGD (arginine-glycine-aspartic acid)-integrin interaction in mesangial cells. Mesangial cells demonstrated significantly less adhesion to matrix oxidized using a metal-catalyzed oxidation system and lost their typical spindle-shaped morphology. N-tert-butyl-alpha-phenylnitrone reversed in part both oxidation and impaired adhesion to matrix. Mesangial cells adhered to plates coated with GRGDSP but demonstrated impaired adhesion to oxidized GRGDSP. Oxidation of this peptide was demonstrated using immunoblot analysis with an antibody to dinitrophenylhydrazine bound to carbonyl groups on oxidized amino acid residues. This represents the first report demonstrating that oxidative modification of extracellular matrix impairs integrin-mediated adhesion and suggests that the mechanism may be oxidative modification of one or more amino acids in the RGD sequence. These data suggest a new mechanism by which cell-matrix interaction may be altered in disease states characterized by enhanced oxidative stress.

Animals↗
PubMed1997

AIDS-associated membranous nephropathy with advanced renal failure: response to prednisone.

We report the case of a patient with acquired immunodeficiency syndrome (AIDS) who developed nephrotic syndrome and progressive renal failure mimicking human immunodeficiency virus (HIV)-associated focal segmental glomerulosclerosis (FSGS) who required initiation of hemodialysis and was found on renal biopsy to have membranous nephropathy. Hepatitis B and C serologies were negative. Although she required hemodialysis, she was treated with prednisone and experienced a progressive decline in her serum creatinine from 10.1 mg/dL to 1.9 mg/dL, which permitted the discontinuation of hemodialysis. After she abruptly discontinued prednisone, her creatinine level increased to 4.8 mg/dL, and she experienced marked worsening of her nephrotic syndrome. Resumption of prednisone resulted in normalization of serum creatinine and reduction in urine protein excretion. No adverse effects of prednisone occurred during this time. She remains off of hemodialysis for 1 year with a serum creatinine level of 1.0 mg/dL and urine protein excretion of 0.4 g/d. Although most patients with HIV infection, nephrotic-range proteinuria, and renal failure have FSGS, a minority may have membranous nephropathy. Although typically not a steroid-responsive lesion in the setting of advanced renal failure, membranous nephropathy may be a highly steroid-responsive lesion in the HIV-infected patient, and treatment may help avert the need for dialysis in a patient population that generally has a poor outcome on dialysis.

Acquired Immunodeficiency Syndrome↗