The use of glucan as immunostimulant in the treatment of paracoccidioidomycosis.

A group of 10 patients, nine of them seriously infected with Paracoccidioides brasiliensis (G1), received glucan (beta-1,3 polyglucose) as an immunostimulant intravenously once a week for one month, followed by monthly doses (10 mg) over an 11-month period, together with a specific anti-fungal agent as an immunostimulant. A second group of eight moderately infected patients (G2) was treated with only the anti-fungal agent. Among the patients in G1, there was only one case of relapse compared with five in G2. Values for the erythrocyte sedimentation rate (ESR) showed a significant difference (P < 0.001) post-treatment in G1 patients, when compared with the pretreatment levels. There was also a significant reduction (P < 0.001) in the level of serum antibodies to P. brasiliensis in the G1 patients in post-treatment examinations. The phytohemagglutinin (PHA) skin test showed a positive reaction among the patients in G1 (P < 0.01) post-treatment and there was a tendency towards an increase in the number of CD4+ T lymphocytes in both groups after treatment. The serum level of tumor necrosis factor (TNF) proved to be significantly higher (P < 0.02) in the G1 patients during treatment. In the G1 patients, the correlation between ESR and TNF tended to be negative whereas that between ESR and serum antibodies was positive. The present results indicate that the patients who received glucan, in spite of being more seriously ill, had a stronger and more favorable response to therapy.

Effect of different glycosaminoglycans in a guinea-pig carotid artery thrombosis model.

Heparin is the most frequently used drug for the prevention and treatment of thrombosis. Its use, however, is restricted by its side-effects. To study the efficacy of other glycosaminoglycans that could substitute heparin in the management of arterial thrombosis, 60 guinea-pigs were randomly allocated into 6 groups: G1 = control, G2 = heparin (150 IU/kg), G3 = heparan sulfate from beef pancreas (2.5 mg/kg), G4 = heparan sulfate from beef lung (2.5 mg/kg), G5 = N-acetylated heparan from beef pancreas, G6 = dermatan sulfate from beef intestine (2.5 mg/kg). Ten minutes after intravenous injection of the drugs, thrombosis was induced by the injection of a 50% glucose solution into a segment of the right carotid artery isolated between 2 thread loops during 10 minutes. Three hours later the artery was re-exposed and if a thrombus was present it was measured, withdrawn and weighed. Thrombin time and activated partial thromboplastin time were measured in all animals. Thrombus developed in 90% of the animals in the control group, 0% in G2 and G3, 62.5% in G4, 87.5% in G5 and G6. Only in the animals treated with heparin the coagulation tests were prolonged. In conclusion, in the used dose only the heparan sulfate from beef pancreas presented an antithrombotic effect similar to heparin in this experimental model.

Effect of vaccination and the immunomodulators "bacillus of Calmette-Guérin, avridine and Propionibacterium acnes" on rabies in mice.

Responses of vaccination and treatment to immunomodulators against rabies in mice were evaluated through macrophage inhibition factor (MIF), intra-pad inoculation (IPI) and serum neutralization (SN) tests and by the detection of gamma-interferon (IFN-gamma). Onco-BCG, Avridine and Propionibacterium acnes were administered to groups of mice. Higher survival rates were found in animals treated with P. acnes. Lower levels of IFN-gamma were observed in the groups of infected and vaccinated mice. The IPI was not effective on detecting the response of delayed-type hypersensitivity. Vaccine induced in the infected animals a more intense response to MIF reaction.

Modulation of antibody response to sheep red blood cells by cyclophosphamide in Calomys callosus (Rodentia).

1. Calomys callosus, a wild rodent reservoir of Trypanosoma cruzi, notably resistant to laboratory infection with this parasite, is currently under study as a new experimental model for Chagas' disease. 2. To investigate the humoral immune response of C. callosus, rodents were injected with sheep red blood cells (SRBC) and the resulting antibody titers measured 0, 5, 9, 14, 20, 27 and 37 days later by the direct agglutination test. 3. Modulation of the antibody response by cyclophosphamide (Cy) was also studied, showing that the administration of 400 or 200 mg Cy/kg body weight one day prior to SRBC inoculation had an immunosuppressive effect. When the 200 mg/kg dose was given on day 0, antibody levels were significantly lower than those of controls on the 5th day after SRBC inoculation; subsequent differences were not statistically significant. 4. When SRBC were injected 5 or 10 days after Cy administration, the same effect was observed, indicating that the time of antigen inoculation is important in antibody modulation. A second dose of 200 mg Cy/kg on day 5 resulted in significant antibody suppression up to the 37th day. The administration of 20 mg Cy/kg resulted in a slight antibody enhancement seen on the 5th day after SRBC inoculation given on day 0. 5. These data demonstrate that cyclophosphamide modulates the T-dependent antibody response in C. callosus in a manner similar to the mouse model.

Does the oxygen tension of coronary sinus blood reflect myocardial oxygen tension?

Coronary sinus blood oxygen tension (CSpO2) and myocardial oxygen tension (MpO2) were measured simultaneously during cardiac ischemia and reperfusion. Oxygen tension was measured using a polarographic method. Myocardial ischemia caused a reduction (5 +/- 1.5%; P less than 0.05) in CSpO2 and a decrease (56.5 +/- 10.1%; P less than 0.001) in MpO2. Reperfusion induced a rapid but transient increase (35.9 +/- 4.3%; P less than 0.001) in CSpO2 above the basal state while MpO2 returned gradually to the basal state. These results indicate that CSpO2 is of little value for the detection of changes in myocardial oxygen metabolism during the initial phase (seconds) of cardiac reperfusion.

Antithrombotic effect of Lonomia obliqua caterpillar bristle extract on experimental venous thrombosis.

The venom of Lonomia obliqua caterpillar may induce a hemorrhagic syndrome in humans, and blood incoagulability by afibrinogenemia when intravenously injected in laboratory animals. The possible antithrombotic and thrombolytic activities of L. obliqua caterpillar bristle extract (LOCBE) were evaluated in this study. The minimal intravenous dose of the extract necessary to induce afibrinogenemia and anticoagulation was 3.0 and 10.0 microg protein/kg body weight for rabbits and rats, respectively. In rabbits, this dose induced total blood incoagulability for at least 10 h and did not reduce the weight of preformed venous thrombi, in contrast to streptokinase (30,000 IU/kg). In rats, pretreatment with 5.0 and 10.0 microg/kg LOCBE prevented the formation of thrombi induced by venous stasis or by injury to the venous endothelium. The dose of 5.0 microg/kg LOCBE did not modify blood coagulation assay parameters but increased bleeding time and decreased plasma factor XIII concentration. When the extract was administered to rats at the dose of 10.0 microg/kg, the blood was totally incoagulable for 6 h. These data show that LOCBE was effective in preventing experimental venous thrombosis in rats, justifying further studies using purified fractions of the extract to clarify the mechanisms of this effect.

Platelet activation following application of an Esmarch bandage and tourniquet in rabbits.

The present study evaluates platelet activation following application of an Esmarch bandage and a tourniquet, procedures commonly employed to provide a bloodless operative field during limb surgery. Platelet aggregation was increased in blood samples taken from rabbits 60 min after an Esmarch bandage was applied to one thigh and immediately released. When this treatment was combined with the application of a tourniquet for 60 min, a procedure which alone did not affect platelet aggregation, results were similar to those obtained following the Esmarch bandage alone. These data suggest that tissue compression produced by application of an Esmarch bandage, but not the ischemia derived from the tourniquet, produced platelet aggregation.

Comparative study of the action of topical heparinoids on the evolution of experimental thrombophlebitis.

The action of three different topical heparinoids on the evolution of experimental thrombophlebitis was studied. Thrombophlebitis was induced in the marginal vein of the ear of rabbits by stasis and injection of hypertonic glucose solution. Forty-eight hours later the animals were allocated to three treatment groups and a control group. The substances were applied over the affected vein three times a day for 6 days and the ears inspected daily by transilumination. After 7 days, the animals were killed and anatomopathological studies performed. No difference in thrombus frequency or inflammatory reaction was observed between the animals treated with heparinoids and the control groups, or among the treated groups.

Changes in myocardial and coronary sinus blood oxygen tension induced by asphyxia and reoxygenation.

1. This study analyzes variations of oxygen tension induced by asphyxia in the myocardium (MpO2) and coronary sinus blood (CSpO2) of the anesthetized open-chest dog. Oxygen tension was measured polarographically and arterial blood pressure and coronary blood flow were recorded simultaneously. 2. Asphyxia increased arterial pressure and coronary blood flow but decreased both MpO2 and CSpO2. 3. During the reoxygenation phase, arterial pressure and coronary flow decreased gradually. Reoxygenation induced a rapid but transient increase in CSpO2 above control levels. In contrast, MpO2 returned gradually to the basal state. 4. The mechanism(s) involved in the differential effects of asphyxia followed by reoxygenation on MpO2 and CSpO2 remain to be elucidated.

Functional and ultrastructural evaluation of myocardial protection provided by intermittent coronary sinus perfusion in the isolated dog heart.

1. The protection offered by intermittent perfusion of cardioplegic solution through the coronary sinus was investigated in isovolumic blood-perfused dog heart preparations submitted to 60 min of ischemia and 45 min of reperfusion. 2. The preparations were divided into three treatment groups: a) coronary sinus, consisting of preparations (N = 10) perfused through the coronary sinus under 40 cm water pressure; b) aortic, consisting of preparations (N = 10) perfused through the aortic stump under 100 mmHg pressure; c) control, consisting of hearts (N = 9) that were not perfused with cardioplegic solution. 3. Properties of contractile capacity and relaxation were markedly impaired in the control group but were preserved to a comparable extent in the groups perfused with cardioplegic solution through the aorta and coronary sinus. Developed pressure decreased in the control group (before ischemia: 70 +/- 5.5 mmHg; after reperfusion: 35 +/- 12 mmHg; P less than 0.05) and didn't vary in the aortic group (from 69 +/- 4 mmHg to 65 +/- 13 mmHg; P greater than 0.05) and coronary sinus group (from 69 +/- 4.6 mmHg to 60 +/- 10 mmHg; P greater than 0.05). Myocardial relaxation was evaluated by the +/- dp/dt ratio. In the control group there was impairment of myocardial relaxation as indicated by an increase of this index after reperfusion (from 1.05 +/- 0.05 to 1.46 +/- 0.23; P less than 0.05), whereas in the aortic (from 1.10 +/- 0.13 to 1.15 +/- 0.20; P greater than 0.05) and the coronary sinus (from 1.03 +/- 0.14 to 1.08 +/- 0.16; P greater than 0.05) groups there was no variation. Ultrastructural changes in the myocardium were negligible in all three groups at the end of reperfusion. 4. We conclude that intermittent perfusion of a hypothermic cardioplegic solution through the coronary sinus is effective for the protection of the myocardium during total ischemia.

Effects of dopamine on the pulmonary circulation of the dog.

The effects of dopamine infusion (10 and 20 micrograms kg-1 min-1) on pulmonary arterial pressure (PAP) and pulmonary arterial resistance (PAR) were studied. Experiments were carried out on 60 anesthetized dogs using two different models: model A, with mechanical perfusion of pulmonary circulation and constant left ventricular output, and model B, with physiologic pulmonary perfusion and non-fixed ventricular output. When pulmonary blood flow was constant, dopamine did not change PAP or PAR at either dose. When cardiac output (CO) was allowed to increase, PAP increased with dopamine at both doses, whereas PAR did not change with 20 micrograms kg-1 min-1 dopamine and was reduced by the 10 micrograms kg-1 min-1 dose. We conclude that the increase in PAP could not be explained solely by the rise in CO, but was probably related to an inhibitory effect of dopamine on pulmonary vascular accommodation and to increases in CO, especially when the drug was utilized at higher doses.

Techniques for temporary shunting of carotid arteries: experimental study in dogs.

In order to study possible differences among temporary shunts for carotid artery surgery, 4 types of shunts were studied in an experimental canine model of extracranial cerebrovascular insufficiency. Twenty five dogs were operated on and divided in five equal groups: one control group without shunt, two groups of animals with a short internal shunt and two groups with a long external shunt, catheters of two different gauges being used for each type of shunt. These shunts were evaluated by systemic arterial pressure (SAP), stump pressure (SP) and carotid blood flow, which were measured before and after carotid clamping, and 5 and 10 minutes after the release of blood flow through the carotid artery or through the shunts. Multivariate analysis of variance showed that all but the shorter and wider shunt acted as a stenosis in the carotid artery, with a decrease of 50% in blood flow. The analysis of other parameters did not show differences among the shunts, suggesting that even acting as a stenosis, no functional pressure alteration occurred with the different shunts in this model.

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.

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.

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.

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.

Alcohol in cerebrospinal fluid (CSF) and alcoholism.

Alcohol levels were measured in 15 cerebrospinal fluid (CSF) samples and 14 blood samples from grade III and IV male alcoholic patients with signs of nervous system involvement, and compared with levels detected in 11 CSF samples and 11 blood samples from abstemious patients or patients with grade I or II alcoholism whose CSF had been found to be normal by routine analysis (controls). Among the alcoholic patients, alcohol levels were lower in the CSF than in blood, whereas the opposite was true for the controls. The possible mechanisms underlying this difference are discussed and the need for further study of this topic is emphasized.

A critical evaluation of the expression of parasitemia in experimental Chagas' disease.

This paper aims to study the best way to express the parasitemia of Trypanosoma cruzi's experimentally infected animals. Individual scores may have a great variability, not emphasized by the majority of the authors. A group of 50 rats infected with 1 x 10(6) trypomastigotes of T. cruzi Y strain was used and the parasitemia was estimated by BRENER's method. The results showed that the median can avoid false results due to very high or low parasitemias but it does not have the mathematic properties necessary for analysis of variance. The comparison of the means of the original and transformed data, with their respective coefficients of variability (CV), showed that the logarithmic mean (Mlog) have the minor value of CV. Therefore, the Mlog is the best way to express the parasitemia when the data show great variability. The number of the animal for group did not affect the variability of data when the Mlog and CV were used.

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.

Liver dysfunction in patients bitten by Crotalus Durissus terrificus (Laurenti, 1768) snakes in Botucatu (State of São Paulo, Brazil).

Thirty-two patients bitten by venomous snakes sixteen by Bothrops spp. and sixteen by Crotalus durissus terrificus were studied. The group comprised thirty males and two females, aged eight to sixty-three years (mean 33 +/- 15). Bromsulphalein tests were increased in the majority of patients bitten by Crotalus durissus terrificus. The correlation coefficient of Spearman was positive between bromsulphalein tests and alanine aminotransferase levels, and between alanine aminotransferase and aspartate aminotransferase levels only in the Crotalus group. The only patient who died was bitten by Crotalus durissus terrificus and showed hydropic degeneration and mitochondrial injury in the liver. It was concluded that the hepatic damage might have been caused by at least two possible mechanisms: venom effect on liver mitochondria and cytokine effects on hepatocyte, specially interleukin-6.