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Biomedical subjects

G Sosa

Publications and source records attributed to G Sosa.

6 recordsLinked to original sources
PubMed1996

Intrathecal synthesis of anti-sulfatide IgG is associated with peripheral nerve disease in acquired immunodeficiency syndrome.

Peripheral nervous system involvement in the acquired immunodeficiency syndrome (AIDS) can take the form of an acute or chronic inflammatory demyelinating polyneuropathy, polyradiculopathy, mononeuropathy multiplex, or autonomic neuropathy. There is no widely held consensus on the etiology of PNS or other neurological complications associated with HIV infection. We report here that PNS disease in HIV-infected individuals is associated with intrathecal synthesis of an antibody directed against sulfatide, a major component of myelin. The anti-sulfatide antibody is also present nonspecifically in serum. The antibody requires the presence of the 3-O-sulfogalactosyl residue for binding and recognizes preferentially the hydroxy fatty acid-containing form of sulfatide. Anti-sulfatide antibodies are therefore one of the humoral factors responsible for demyelinating diseases in AIDS patients.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Time course analysis of serum and urinary proteins by SDS-PAGE in experimental nephrotic syndrome.

Serum and urinary proteins from rats with nephrotic syndrome (NS) induced by puromycin aminonucleoside (PAN) were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Analysis was made on days 2, 4, 6, 8, 10, 12, 16, 20, and 30 after PAN injection. Data were compared with control rats (C). Rats developed proteinuria on days 4-30 and hypoproteinemia on days 4-16. Total protein concentration in serum and urine was similar on day 6. SDS-PAGE revealed that urinary albumin augmented on days 4-30 and serum albumin decreased markedly on days 4-20. Albumin concentration in serum and urine was similar on days 4-16. In addition, the study examined serum changes of 7 other proteins (designed as A, B, C, D, E, F, and G) which appeared or increased in urine, and whose molecular weights were higher (A, B, and C) or lower (D, E, F, and G) than that of albumin. In serum, protein A remained unchanged; protein B and G increased; proteins C, D, E, and F decreased. The qualitative pattern of urinary proteins remained essentially unchanged on days 4-30. During the intense proteinuria, the serum concentrations of protein B and albumin were similar and the urine concentrations of proteins C and D became comparable to that found in serum. These 7 serum proteins did not show the same behavior although all of them were excreted in urine. These data indicate that in PAN-nephrotic rats: (a) urinary proteins can be of low and high molecular weight, (b) serum proteins can be regulated independently of their urinary excretion and molecular weight, (c) the urine concentration of total protein and some specific proteins can reach values similar to that found in serum during the intense hypoproteinemia, and (d) the qualitative pattern of urinary proteins was unrelated to the magnitude of proteinuria.

Analysis of Variance↗
PubMed1994

Escherichia coli endotoxin depresses left ventricular contractility in neonatal lambs.

We evaluated the effects of Escherichia coli endotoxin on the peripheral vascular hemodynamics and myocardial function of the newborn lamb to understand how gram-negative endotoxemia can lead to cardiovascular collapse in newborn infants. Fifteen lambs, 0-3 d old, were acutely instrumented with a micromanometer-tipped catheter and two pairs of ultrasonic crystals to measure left ventricular (LV) pressure and LV anterior-posterior and septal-free wall dimensions, a fluid-filled catheter for monitoring aortic pressure, and an electromagnetic flow probe to measure systemic blood flow. Cardiovascular performance was evaluated by measuring or deriving the following variables: mean arterial blood pressure (MABP), LV pressure, heart rate, stroke volume, systemic vascular resistance, LV dp/dt, end-diastolic area, arterial elastance, and end-systolic elastance (the slope of the end-systolic pressure-area relationship) as an index of contractility independent of loading conditions and heart rate. Once instrumented, nine lambs received endotoxin, 0.5 mg/kg i.v., and six animals, serving as controls, received a saline infusion. Of the endotoxin-treated lambs, five survived the duration of the study (120 min from the beginning of the endotoxin infusion), and four died by 90 min from the beginning of the endotoxin infusion. No significant changes in any of the cardiovascular variables occurred in the control group. A significant decrease in MABP was seen in all endotoxin-treated animals by 45 min after the beginning of the endotoxin infusion. MABP decreased by 52% from baseline in the survivors and 38% in the nonsurvivors. In the survivors, the MABP stabilized with saline boluses, whereas in the nonsurvivors MABP continued to decrease until death.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Brainstem bilirubin toxicity in the newborn primate may be promoted and reversed by modulating PCO2.

The auditory brainstem response (ABR) was monitored during infusion of bilirubin in six ventilated newborn rhesus monkeys (138-145 d gestation) while acute changes in pH were produced by varying inspired CO2. Prolonged respiratory acidosis without bilirubin infusion produced minimal changes in the ABR (one animal). CO2 exposure, usually initiated when the bilirubin level reached approximately 20 mg/dL, decreased arterial pH to values ranging from 6.85 to 7.10. ABR changes, including prolongation of the wave II-IV peak to peak intervals and decreased wave amplitudes, first developed 2-4 h after initial exposure to CO2. Total and unbound bilirubin levels at this time ranged from 376 to 564 mumol/L (22-33 mg/dL) and 38 to 65 nmol/L (2.5-3.8 micrograms/dL), respectively. Correction of respiratory acidosis produced partial to complete reversal of ABR changes within 3 to 20 min. Reexposure to CO2 immediately reproduced the ABR abnormality. Production and reversal of the abnormal ABR was obtained through two to three cycles in three animals. Thus, when the brainstem bilirubin level was near the threshold for toxicity, the effect of changes in PCO2 on the ABR were immediate, suggesting that auditory pathway toxicity is initially mediated by a reversible pH-dependent bilirubin-membrane complex. In contrast to humans, in monkeys auditory toxicity appeared to be a late manifestation of bilirubin toxicity, inasmuch as all monkeys were obtunded and apneic 30-70 min before ABR abnormalities appeared. Notwithstanding these limitations, the results support the hypothesis that bilirubin toxicity can be both promoted and reversed by modulating brain pH.

Acidosis, Respiratory↗
PubMed1988

Restricted pulmonary function in cystic fibrosis.

Some patients with cystic fibrosis have reduced pulmonary volumes, indicating a restrictive pattern of pulmonary disease. We identified ten patients with pulmonary functional evidence of restriction among 158 patients with cystic fibrosis followed at the University of California San Diego Medical Center in 1984 and 1985. We characterized the radiographic, pulmonary functional, and clinical characteristics of these restricted patients compared to matched nonrestricted patients. Pulmonary volumes were measured by three different techniques: plethysmography; nitrogen washout; and radiography. Except for plethysmographic pulmonary volumes, there were no significant differences between the matched restricted and nonrestricted patients. Radiographic pulmonary volume tended to overestimate gas volume measured by the other techniques. Differences among these techniques (thought to represent air-space filling) correlated best with radiographic evidence of air trapping and bronchial markings and not with parenchymal lesions. Serial pulmonary function tests demonstrated changes in pulmonary volume in several patients and a trend toward improvement in pulmonary volume in the restricted patients over time. We conclude that restricted pulmonary function does not necessarily indicate more severe disease in patients with cystic fibrosis and may be reversible in some. The mechanism of restriction may be related more to radiographic evidence of airway disease than to parenchymal abnormalities.

Adult↗