Intratracheal injection of nickel chloride and copper-zinc superoxide dismutase activity in lung of rats

Superoxide radical (O2-) is a free radical that may be involved in various toxic processes. Cu--Zn superoxide dismutase catalyses the dismutation of the superoxide free radical and protects cells from oxidative damage, and it has been used clinically. The concentration of Ni2+ and Cu--Zn superoxide dismutase activity were measured in lungs of rats at time intervals of 5, 12, 19, 26, 33, and 40 days following an intratracheal injection of 127 nmol of NiCl2. Nickel chloride increased nickel content and resulted in a significant increase of Cu--Zn superoxide dismutase activity in lungs. This elevation of Cu--Zn superoxide dismutase activity was highest on the 12th day (approximately threefold) and is at levels comparable to controls rats on day 40 onwards. Since Cu--Zn superoxide dismutase activity was increased in lung throughout our experimental period without corresponding increases of Cu2+ and Zn2+, we speculate that the elevation of Cu--Zn superoxide dismutase activity might be due to an increased half-life of the enzyme, induced by nickel.

[Captopril in mild and moderate arterial hypertension resistant to diuretic therapy. A multicenter study]

PURPOSE

To evaluate the antihypertensive effect of captopril in mild and moderate hypertensive patients uncontrolled with diuretics.

METHODS

Low dose of captopril (25 to 50 mg) bid were associated during 9 weeks in 120 patients previously treated with 100 mg of hydrochlorothiazide. A subgroup of patients (74) were followed additionally for 3 weeks with the same dose of the drugs administered as a single dose. The patients were clinically evaluated after two weeks placebo, and each three weeks of active drugs. Blood pressure normalization were considered when diastolic arterial pressure was < or = 90 mmHg. Laboratory tests were measured before diuretic, before captopril and at the end of combined twelve weeks treatment.

RESULTS

After 15 days washout, the baseline supine arterial pressure, 168 +/- 2/ 109 +/- 1 mmHg decrease significantly with diuretic to 151 +/- 1/ 101 +/- 1 mmHg and the drop was further increased with captopril b.i.d., with a mean dose of 44 +/- 1 mg, to 137 +/- 1/ 90 +/- 1 mmHg. Blood pressure normalization was obtained in 58% patients with captopril b.i.d. and in 63% as single dose. Blood pressure normalization was achieved in 63% of non-white patients and in 56% patients over 45 years old. Plasmatic potassium decreased significantly with diuretic and did not recovered when captopril was associated.

CONCLUSION

Our results indicate that the addition of low dose of captopril twice or once a day may result in a marked additional blood pressure reduction in cases of insufficient control by the diuretic alone.

Modulation of parasitemia and antibody response to Trypanosoma cruzi by cyclophosphamide in Calomys callosus (Rodentia, Cricetidae)

Calomys callosus a wild rodent, previously described as harboring Trypanosoma cruzi, has a low susceptibility to infection by this protozoan. Experiments were designed to evaluate the contribution of the immune response to the resistance to T. cruzi infection exhibited by C. calossus. Animals were submitted to injections of high (200 mg/kg body weight) and low (20 mg/kg body weight) doses of cyclophosphamide on days -1 or -1 and +5, and inoculated with 4 x 10(3) T. cruzi on day O. Parasitemia, mortality and antibody response as measured by direct agglutination of trypomastigotes were observed. Two hundred mg doses of cyclophosphamide resulted in higher parasitemia and mortality as well as in suppression of the antibody response. A single dose of 20 mg enhanced antibody levels on the 20th day after infection, while an additional dose did not further increase antibody production. Parasitemia levels were not depressed, but rather increased in both these groups as compared to untreated controls. Passive transfer of hyperimmune C. callosus anti-T. cruzi serum to cyclophosphamide immunosuppressed animals resulted in lower parasitemia and mortality rates. These results indicate that the immune response plays an important role in the resistance of C. callossus to T. cruzi.

[Mortality due to neoplasms in Brazil (1980/1983/1985): grouping by states, behavior and trends]

Mortality caused by neoplasms in Brazil was examined by means of official Ministry of Health data covering 26 of the Federal Units and 13 different tumoral sites and referring to the years 1980, 1983 and 1985. Both cluster analyses and those of principal components have shown heterogeneous behaviour as between the different regions of the country in relation to the 13 variants studied. The main discriminatory elements are the trachea/bronchus/lung malign neoplasms followed by those of stomach, pancreas, colon and larynx. Complementary analyses have demonstrated a tendency to an increase in the mortality rate due to prostate malign neoplasms (17.74%), followed by those of trachea/bronchus/lung (15.22%), breast (11.32%), pancreas (10.23%), colon (8.08%), uterine colon (6.45%) and larynx (6.36). There has been a decrease of the mortality due to benign neoplasms/carcinoma "in situ"/others (27.37%), malign rectus neoplasms of the sigmoid/anus (7.67%), stomach (5.31%), of other non-specific locations in the uterus (2.56%), of leukaemia (0.70%) and malign neoplasms of the oesophagus (0.44%). Maling neoplasms of the stomach have been the main cause of cancer mortality in Brazil accounting for 21.27% of the mean total, followed by of the malign neoplasms trachea/bronchus/lung (17.52% of the general average). The mortality rates by esophageal malign neoplasms in Rio Grande do Sul is stressed.

Heparin, heparin plus ASA and dipyridamole, and arteriovenous fistula as adjuvant methods to prevent rethrombosis after venous thrombectomy. Experimental study in rabbits

Venous rethrombosis following thrombectomy is a common event. The aim of the present study was to verify the action of heparin, heparin plus acetyl salicylic acid (ASA) and dipyridamole, and of an arteriovenous fistula (AVF) in the prevention of this complication. Thrombosis was induced in 48 male rabbits by the injection of thrombin in a segment of the left jugular vein, in which the blood flow was arrested for 10 minutes. After 48 hours, the animals were randomly allocated into one of 4 groups of treatment: (1) control, (2) subcutaneous heparin (600 S.I. Units/kg--8/8 hours), (3) heparin, in the same dose, plus ASA (10 mg/kg/once a day), and dipyridamole (0.5 mg/kg thrice a day), (4) an AVF was surgically constructed between the left carotid artery and the left maxillar vein. After 30 minutes, thrombectomy was performed. The venous blood flow, the hematocrit, activated partial thromboplastin time and thrombin time tests were performed before, right after the thrombectomy and 48 hours after thrombectomy. Venography was performed after thrombectomy and at the end of the experiment. The animals were killed 48 hours after thrombectomy and the veins were examined macroscopically. Venous rethrombosis was significantly prevented only in the AVF group (9/12), when compared to control group (0/12), heparin group (1/12) and heparin plus antiaggregating agents group (2/12). These results validate further clinical and experimental investigations with the use of AVF to prevent rethrombosis after venous thrombectomy, when a reduction of venous flow is present.

Isoniazid acetylating phenotype in patients with paracoccidioidomycosis and its relationship with serum sulfadoxin levels, glucose-6-phosphate dehydrogenase and glutathione reductase activities

The authors evaluated the isoniazid acetylating phenotype and measured hematocrit, hemoglobin, glucose-6-phosphate dehydrogenase and glutathione reductase activities plus serum sulfadoxin levels in 39 patients with paracoccidioidomycosis (33 males and 6 females) aged 17 to 58 years. Twenty one (53.84%) of the patients presented a slow acetylating phenotype and 18(46.16%) a fast acetylating phenotype. Glucose-6-phosphate-dehydrogenase (G6PD) activity was decreased in 5(23.80%) slow acetylators and in 4(22.22%) fast acetylators. Glutathione reductase activity was decreased in 14(66.66%) slow acetylators and in 12(66.66%) fast acetylators. Serum levels of free and total sulfadoxin were higher in slow acetylator (p less than 0.02). Analysis of the results permitted us to conclude that serum sulfadoxin levels are related to the acetylator phenotype. Furthermore, sulfadoxin levels were always above 50 micrograms/ml, a value considered therapeutic. Glutathione reductase deficiency observed in 66% of patients may be related to the intestinal malabsorption of nutrients, among them riboflavin, a FAD precursor vitamin, in patients with paracoceidioidomycosis.

Interaction among zinc, glucose, and insulin in normal individuals during glucose and tolbutamid perfusion

Reports in the literature have shown that acute or chronic zinc administration may cause hyperglycemia, with a fall in serum or insular insulin occurring in experimental animals. On the other hand, under conditions of both acute and chronic hyperglycemia, an increase, a decrease, or a normal level of blood zinc has been observed in studies conducted on humans. Thus, the objective of the investigation described here was to determine the relationship existing among zinc, glucose, and insulin under acute conditions. Thirty-six subjects of both sexes (mean age, 23 yr) were tested at 7:00 A.M. after a 12-h fast. Two antecubital veins of both forearms were punctured and maintained with physiological saline. Three experiments were performed in which zinc was administered orally, and hypertonic glucose and tolbutamid were administered intravenously. Blood samples were then collected over a period ranging from 93 to 240 min after the basal times of -30 and 0 min. Hyperzincemia did not cause changes in plasma glucose or insulin either in the absence of or during perfusion of glucose. Hyperglycemia, hypoglycemia, and hyperinsulinemia did not modify serum zinc levels. These results demonstrate that acute zinc administration did not change carbohydrate metabolism and that sudden variations in glucose and insulin levels did not modify the serum profile of zinc.

[Grouping of countries according to basic and economic indicators]

"Countries are grouped according to a collection of basic and economic indicators published by UNICEF, in 1990. Two multivariate statistical methods were used: Principal Component Analysis and Cluster Analysis. The study [covers] 36 countries of the Americas, Europe (including the USSR), the Middle East, Asia and the other continents; they were chosen to include countries having complete information (for the 16 variables used) and in the most varied stages of development. The first principal component was interpreted as a measure of the degree of development...with emphasis on the position occupied by Brazil (13th place among the 25 American countries). In general, the most discriminative variables were the mortality rates of infants and children under five, and life expectancy...." (SUMMARY IN ENG)

Characteristics of Staphylococcus aureus from subclinical bovine mastitis in Brazil

A total of 127 Staphylococcus aureus strains isolated from milk samples of cows with subclinical bovine mastitis was examined for biotype, phage pattern, in-vitro antibiotic susceptibilities and ability to produce enterotoxins. The majority of the strains showed features consistent with bovine rather than human origin. All strains were sensitive to the antibiotics tested, except penicillin and streptomycin. Enterotoxigenicity was observed in 6 (4.7%) strains and only enterotoxins A and C were produced.

Antimicrobial susceptibilities of Staphylococcus aureus isolated from animal and human sources in Brazil

The susceptibilities of 760 Staphylococcus aureus strains isolated from animal infections (400), human infections (300) and healthy human carriers (60) to seven antibiotics were determined by an agar dilution technique. The isolates from human infections were more resistant to a wider spectrum of antibiotics than were the strains from animal infections and healthy human carriers. Amikacin and gentamicin were the most active drugs against all groups of strains.

Interrelationships of zinc with glucose and insulin metabolism in humans

Hyperzincemia has been reported to cause alterations in the homeostasis of glycid metabolism. To determine this effect on plasma glucose and insulin levels, we studied 36 normal individuals of both sexes aged 22-26 y after a 12-h fast. The tests were initiated at 7:00 AM when an antecubital vein was punctured and a device for infusion was installed and maintained with physiological saline. Zinc was administered orally at 8:00 AM. Subjects were divided into an experimental group of 22 individuals who received doses of 25, 37.5, and 50 mg of zinc and a control group of 14 individuals. Blood samples were collected over a period of 240 min after the basal samples (-30 and 0 min). We did not detect any change in plasma glucose or insulin levels, a fact that we attribute either to the ineffectiveness of the 50 mg dose of zinc or to the lack of human response to the acute action of this trace element. The individuals who ingested zinc showed a significant fall in plasma cortisol, probably caused by the action of this trace element.

Measurement of glucose-6-phosphate dehydrogenase and glutathione reductase activity in patients with paracoccidioidomycosis treated with ketoconazole

Hemoglobin rates, hematocrit and glucose-6-phosphate dehydrogenase (G6PD) and glutathione reductase activities were measured in 38 patients with paracoccidioidomycosis treated with ketoconazole or sulfadoxin, and in 13 normal individuals. Ketoconazole-treated patients showed reduced G6PD and glutathione reductase activities. One of these patients was found to be G6PD-deficient and suffered a hemolytic episode during treatment, which, however, did not require interruption of therapy. The authors suggest that patients showing an erythrocyte enzyme defect should be monitored hematologically during treatment with ketoconazole. They also suggest that ketoconazole is an oxidant drug in addition to being a possible inhibitor of antioxidant erythrocyte enzymes.

Glucose-6-phosphate dehydrogenase and glutathione reductase activity in methemoglobin reduction by methylene blue and cystamine. Study on glucose-6-phosphate dehydrogenase-deficient individuals, on normal subjects and on riboflavin-treated subjects

The authors have standardized methods for evaluation of the activity of the glucose-6-phosphate dehydrogenase and of glutathione reductase. The general principle of the first method was based on methemoglobin formation by sodium nitrite followed by stimulation of the glucose-6-phosphate dehydrogenase with methylene blue. Forty six adults (23 males and 23 females) were studied. Subjects were not G6PD deficient and were aged 20 to 30 years. The results showed that methemoglobin reduction by methylene blue was 154.40 and 139.90 mg/min (p<0.05) for males and females, respectively, in whole blood, and 221.10 and 207.85 mg/min (n.s.), respectively, in washed red cells. These data showed that using washed red cells and 0.7g% sodium nitrite concentration produced no differences between sexes and also shortened reading time for the residual amount of methemoglobin to 90 minutes. Glutathione reductase activity was evaluated on the basis of the fact that cystamine (a thiol agent) binds to the SH groups of hemoglobin, forming complexes. These complexes are reversed by the action of glutathione reductase, with methemoglobin reduction occurring simultaneously with this reaction. Thirty two adults (16 males and 16 females) were studied. Subjects were not G6PD deficient and were aged 20 to 30 years. Methemoglobin reduction by cystamine was 81.27 and 91.13 mg/min (p<0.01) for males and females, respectively. These data showed that using washed red cells and 0.1 M cystamine concentration permits a reading of the residual amount of methemoglobin at 180 minutes of incubation. Glutathione reductase activity was evaluated by methemoglobin reduction by cystamine in 14 females before and after treatment with 10 mg riboflavin per day for 8 days. The results were 73.69 and 94.26 jug/min (p<0.01) before and after treatment, showing that riboflavin treatment increase glutathione reductase activity even in normal individuals. Three Black G6PD-deficient individuals (2 males and 1 female) were also studied. The G6PD and glutathione reductase were partially activated, the change being more intense in males. On the basis of race and of the laboratory characteristics observed, it is possible to suggest that the G6PD deficiency of these individuals is of the African type and that the female is heterozygous for this deficiency. Analysis of the results as a whole permitted us to conclude that the methods proposed here were efficient for evaluating the activity of the glucose-6-phosphate dehydrogenase and of glutathione reductase. The latter is dependent on the pentose pathway, which generates NADPH, and on riboflavin, a FAD precursor vitamin.

Immunological assessment and its predictive role in malnourished infants with diarrhoea and/or systemic infections

The Immune capacity of 47 marasmic 1–12 months old ill infants with weights below 75 per cent of Brazilian standards and of 12 well-nourished healthy controls was studied, by measuring: the absolute and relative T and B lymphocyte subpopulatioits, the blastogenic response to phytohaemagglutinin (PHA), expressed as stimulation index (SI), and the delayed hypersensitivity skin test with PHA. Eight (17 per cent) of the malnourished infants died and results were evaluated with respect to ultimate outcome. In addition a discriminant analysis was retrospectively applied to the immunological data of the two groups of malnourished infants. Both groups of malnourished infants presented significantly lower values than the control group for all measurements, although not very evident for B lymphocytes. The immunodepression was more intense for the infants who died than for those who survived, as shown by significantly lower values for the SI, the skin test, and by the discriminant analysis. The discriminant analysis led to a linear predictive model which accurately classified 85 per cent of the survivors and 100 per cent of those who died. It was con cluded that immunological parameters may be useful to select prospectively those infants who need a different therapeutic approach because of their high risk of mortality.

Is coronary sinus blood oxygen tension behavior determined by myocardial oxygen tension variation during cardiac reperfusion?

The relationship between coronary sinus blood oxygen tension (CSPO2) and myocardial oxygen tension (MPO2) variations during cardiac ischemia and reperfusion was studied in anesthetized open-chest dogs. Oxygen tension was measured by a polarographic method. Ischemia resulted in a slightly decreased CSPO2 and a more pronounced reduction of MPO2. After reperfusion the CSPO2 rose rapidly and transiently before it returned gradually to the control level. By contrast, during the recovery period, the MPO2 increased slowly, with recovery occurring long after the peak of CSPO2. These data suggest that during the reperfusion phase, the CSPO2 variation is probably due to opening of the myocardial arteriovenous shunts instead of an increase of flow through the myocardial capillary bed.

Lumbar sympathectomy and distal arteriovenous fistula as adjuncts to prevent arterial rethrombosis after thrombectomy: experimental study in dogs

The role of lumbar sympathectomy and distal arteriovenous fistula (AVF) in preventing rethrombosis of femoral arteries with intimal injury and poor run-off was studied in 21 dogs. Femoral artery thrombosis was induced by endothelial lesion in all animals (phase 1) and 24 hours later the arterial flow was restored by thrombectomy. The dogs were then randomly allocated into 3 experimental groups: control, sympathectomy, and AVF (phase 2). Critical stenosis of the popliteal artery was then created by a partially occluding ligature in all animals in order to simulate poor run-off. After 24 hours the femoral arteries were studied for the presence of rethrombosis (phase 3). At the end of phase 2 and during phase 3, femoral pressure and flow, fluorescein circulation time and paw temperature were measured, and arteriography was done. Arterial rethrombosis was significantly prevented in the AVF group (6/7) when compared to the control group (2/7) or the sympathectomy group (1/7). These data suggest an effective action of an adjuvant AVF, but not of sympathectomy in preventing rethrombosis after thrombectomy in arteries with poor run-off.

[Malaria in the municipality of Humaitá, State of Amazonas. XXI. Prevalence of glucose-6-phosphate dehydrogenase in a population sample and in patients with Plasmodium falciparum malaria]

Os autores estudaram a prevalência da deficiência de glicose-6-fosfato desidrogenase (G6PD), pelo método de BREWER et alii, em 141 indivíduos da população do município de Humaitá, Estado do Amazonas. Destes, 128 eram amazônides, 67 dos quais nunca tiveram malária, enquanto que 61 tinham tido ou estavam tendo a doença; os 13 restantes que estavam com malária não eram arnazônides. Os resultados revelaram que 7 arnazônides (4,96%), eram deficientes. Destes, 5 eram do sexo feminino e 2 do masculino. Em todos os indivíduos do sexo feminino o teste foi positivo com comportamento do tipo heterozigoto. Dos indivíduos deficientes, 4 nunca tinham tido malária; dos outros 3, 2 apresentavam a reação de hemaglutinação positiva com título 1/16 e o terceiro estava tendo malária causada pelo Plasmodium falciparum pela primeira vez. Este doente apresentou forma benigna de malária evoluindo para cura clínica e parasitológica no 3.° dia de tratamento com a clindamicina. Nenhum dos 13 doentes não arnazônides apresentava deficiência de G6PD. Dessa forma, não houve diferença na prevalência da deficiência de G6PD em arnazônides que nunca tiveram malária e em arnazônides que tinham tido ou estavam tendo a doença. Portanto, os indivíduos com deficiência de G6PD estão sujeitos a infecções por Plasmodium falciparum na mesma proporção que os não deficientes. Por outro lado, o aumento da prevalência da deficiência de G6PD, na amostra estudada, poderia estar relacionado com a pressão seletiva exercida pela malária em população submetida à homozigose.

Delayed results of treatment of paracoccidioidomycosis with amphotericin B plus sulfamides versus amphotericin B alone

A delayed evaluation of two groups of patients with paracoccidioidomycosis was carried out. Both groups were treated with amphotericin B, "but one of them was submitted to maintenance treatment with sulfonamides. Statistical analysis showed that treatment is more effective when patients are maintained with sulfonamide drugs.