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Biomedical subjects

H Rocha

Publications and source records attributed to H Rocha.

At least 19 recordsLinked to original sources
PubMed1992

Immunologic markers of clinical evolution in children recently infected with Leishmania donovani chagasi.

The study attempted to identify immunologic markers for progression of Leishmania donovani chagasi infection to disease in children in an area endemic for visceral leishmaniasis (VL). [3H]thymidine uptake of lymphocytes stimulated with L. donovani chagasi antigen from children with asymptomatic infection (25,286 +/- 11,648) and from children with self-healing subclinical infection (15,511 +/- 4681) was greater (P = .001) than that observed with lymphocytes from children who progressed to classic VL (4811 +/- 2984). The interferon-gamma (IFN-gamma) levels from asymptomatic and subclinically infected children (74 +/- 90 units/ml) were higher (P = .02) than those observed in children who progressed to VL (7 +/- 8 units/ml). Absence of lymphocyte blastogenesis and IFN-gamma production were associated with progression of infection to classic VL. In the presence of these markers, children should be closely followed to identify signs and symptoms that would permit early initiation of therapy.

Adolescent↗
PubMed1991

Soluble IL-2 receptor as an agent of serum-mediated suppression in human visceral leishmaniasis.

In visceral leishmaniasis (VL), patient's lymphocytes are not activated by leishmania Ag stimulation, and their sera exhibit a potent nonspecific suppressive effect on the responses of normal lymphocytes. Sera were obtained from 33 VL patients, eight patients with subclinical VL, and from 27 normal volunteers. Only sera from VL patients markedly reduced Con A-induced lymphocyte proliferative responses, as well as IL-2 or IFN-gamma production by normal lymphocytes. Addition of exogenous human rIL-2 to cultures containing VL patient sera partially reversed the normal lymphocyte proliferative capacity and restored IFN-gamma production. This phenomenon was consistent with the presence of greatly elevated levels of soluble IL-2R (sIL-2R) in VL patients' sera (4299 +/- 2351 U/ml), well above those of normal sera (180 +/- 94 U/ml), or of sera from patients with subclinical leishmania infection without immunosuppression (1002 +/- 281 U/ml). Furthermore, the removal of sIL-2R reduced VL serum suppressive activity as evaluated by effects on IL-2 and on IFN-gamma production. These data suggest the participation of high levels of sIL-2R in the serum-mediated suppression in VL.

Concanavalin A↗
PubMed1990

Bacterial infections in patients with visceral leishmaniasis.

Bacterial infections are often seen in patients with visceral leishmaniasis. To determine the incidence of such infection and the more common infectious agents, 30 consecutive patients with visceral leishmaniasis were followed throughout hospitalization. There were 24 episodes of bacterial infection in 18 patients (60%). The incidence of bacterial infections in these patients was 22.2/1000 days of admission. The proportion of patients becoming infected by time was significantly greater in the visceral leishmaniasis group than in controls (P less than .01). The skin, respiratory tract, and middle ear were the most common sites of infection, and Pseudomonas aeruginosa and Staphylococcus aureus were the most common agents. Low-grade-virulence bacteria (e.g., Serratia and Providencia species) were also isolated from some cases. Bacterial infections (mainly nosocomial) in patients with visceral leishmaniasis tend to be severe and can cause death. When bacterial infection is suspected in these patients, empiric antibiotic therapy should be started immediately, including coverage for P. aeruginosa and S. aureus, after appropriate diagnostic procedures are taken.

Adolescent↗
PubMed1977

The role of glutathione in renal cortical tissue. Effects of diamide on Na+ and GSSG levels, amino acid transport and Na+-K+-ATPase activity.

The effects of diamide were studied in rat kidney cortical tissue. It was found that diamide increased oxidized glutathione levels and inhibited Na+-K+-ATPase activity. Consistent with this finding was the observation that diamide compromised the sodium gradients maintained in renal cortical slices. Amino acid transport studies with ouabain or a sodium-free buffer indicated that diamide interferes with both Na+-dependent and Na+-independent transport systems. These results indicate that diamide has a number of different effects on renal cortical tissue and emphasize the important role of glutathione in maintaining control of a number of key metabolic pathways.

Adenosine Triphosphatases↗
PubMed1977

In vitro antibiotic susceptibility of salmonellae.

In vitro antibiotic susceptibilities were determined for 101 strains of salmonellae. Resistance to chloramphenicol and ampicillin was low. Cefamandole was active against the majority of strains and deserves further evaluation.

Ampicillin↗
PubMed1977

Effect of acute experimental uremia on the stability of liver lysosomal membranes.

Acute uremia was induced in male Swiss albino mice by complete urethral ligation and the animals were sacrificed 2, 4-6, 24, and 48 h after operation. Sham-opeated animals (without the urethral ligation) were similarly treated. The blood urea levels of animals with total urinary tract obstruction went up to 175 mg/100 ml at 4-6 h of urethral ligation and reached an average level of 827 mg/100 ml at 48 h, while the control group exhibited and average blood urea level of 37 mg/100 ml. Lysosomes obtained from livers of uremic mice sacrificed at different time intervals demonstrated a lability of the lysosomal membranes (as determined by the acid phosphatase activity in mU/mg) which was maximal at 4-6 h of urethral ligation, declining towards normal at 24 and 48 h, despite an increase in the animal's blood urea. In vitro studies exposing liver lysosomes to progressively higher urea concentrations (differences of as much as 100,000 times) did not reveal any effect of urea upon the stability of lysosomal membranes. The reason for the lability of lysosomal membranes in the uremic group was not apparent in the present study.

Acid Phosphatase↗
PubMed1977

["Transfer factor" in ophthalmology (author's transl)].

After considering general preliminary immunological aspects, the author discuss the "transfer factor" of Lawrence (TF) which is one of the lymphokines that are produced by the thymus-dependent lymphocytes (LT). This factor whose nature and the probable constituent fractions are also considered, is the initiator of the cellular immunity. In immunodeficiencies, the LT should be stimulated by introducing the TF in the organism (immunotherapy). The possible use of other immunostimulating substances, which could replace the TF (levamisole BCG, thymosine), is also presented. Finally the author emphasize the large perspectives in the use of these factors in Ophthalmology: herpes, uveitis, melanoma, primary retinitis pigmentosa etc.).

Antigen-Antibody Complex↗
PubMed1976

The effect of acute uremia on liver mitochondrial activity.

The effect of acute uremia on the liver mitochondrial activity was studied in Swiss albino mice subjected to complete urethral obstruction and sacrificed at different time intervals. The specific respiratory coefficient (measured as microliters of oxygen utilized per milligram of total proteins X 10(-1)) was similar in uremic and sham-operated control groups. The utilization of succinate as substrate was also similar in uremic and controls. There was a tendency for decreasing utilization of alpha-glutarate as substrate by the uremic group, particularly after 48 h of total urinary obstruction. There was no correlation between the retention of urea and the degree of mitochondrial respiratory inhibition.

Acute Disease↗
PubMed1976

Renal involvement in patients with hepatosplenic Schistosomiasis mansoni.

In a prospective study of renal involvement in 100 consecutively hospitalized patients with hepatosplenic schistosomiasis mansoni, 15 exhibited persistent proteinuria of varying degree, which in 6 instances was accompanied by hypertension. Nine patients had the nephrotic syndrome. The most common glomerular lesion in this group was membrano-proliferative glomerulonephritis. Surgical biospy obtained during splenectomy in 15 patients without clinical evidence of renal involvement showed glomerular lesions in 6 instances. Focal proliferative glomerulonephritis was the most common lesion in this group. The detection of silent glomerular lesions in patients with Schistosoma mansoni infection suggests that the glomerular alterations may precede clinical manifestations of renal disease.

Adult↗
PubMed1976

Spectral changes of nucleic acids and nucleotide solutions at the 190-220nm region.

Nucleic acids and nucleotide solutions have between 190 and 220 nm an hypo-bathochromic effect electrostatistically induced by acylic groups or by effective binding of several substances. In the former case, with DNA or RNA, the effect reverts through gel filtration and dialysis. In the latter case no reversion occurs. This is proposed as a probe for complex formation with the nucleic acid bases. Thermal denaturation of DNA solutions gives to the above mentioned maximum, an hyperchromicity somewhat different from the usually obtained at 260 nm.

Animals↗
PubMed1975

Serum creatine phosphokinase in leptospirosis.

Serum creatine phosphokinase (CPK) and serum glutamic oxaloacetic and pyruvic transaminase (SGOT, SGPT) levels were determined in 61 patients with leptospirosis and 16 with viral hepatitis during the acute phase of illness. The CPK value was elevated in 29 leptospirosis patients and normal in all 16 hepatitis patients. Conversely, mean SGOT and SGPT levels were lower in leptospirosis patients. The CPK determination is a simple test that may provide diagnostic information in a jaundiced patient, particularly when characteristic manifestations of leptospirosis are absent. The pattern of greatly elevated CPK levels with only modest elevations in transaminase values in an acutely jaundiced patient should strongly suggest a diagnosis of leptospirosis.

Acute Disease↗
PubMedDate not supplied

Etiology and mortality of bacterial meningitis in northeastern Brazil.

Little is known of the current incidence and mortality of meningitis in developing nations, especially in Latin America. We reviewed all cases of meningitis in an isolation-fever hospital in Salvador, Brazil, for the decade 1973-1982. Of all admissions, 6,751 (27%) were for meningitis; 4,100 (61%) of these cases were of definite or probable bacterial etiology. Children younger than 15 years accounted for 79% of cases, and 45% of cases were in children under 2 years. The overall case fatality rate was 33%, with 50% of these deaths occurring within 48 hours of hospitalization. Neisseria meningitidis was the etiologic agent in 32% of the cases, with a case fatality rate of 14%. Epidemics caused by N. meningitidis group C, then group A, in 1974-1978 accounted for 60% of the cases. Streptococcus pneumoniae caused 17% of cases, with a case fatality rate of 59%. Haemophilus influenzae type b, the most common cause of nonepidemic meningitis, caused 23% of all cases, with a case fatality rate of 38%. Enterobacteriaceae were the etiology in only 3.6% of patients, but the case fatality rate was 86%. Cultures were negative in 18% of cases with purulent cerebrospinal fluid. A total of 84% of H. influenzae, 40% of S. pneumoniae, 78% of Enterobacteriaceae, and 15% of N. meningitidis cases occurred in children less than 2 years of age. Case fatality rates were highest in this group. Vaccines protective for this age group are urgently needed.

Adolescent↗