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Biomedical subjects

L Silva

Publications and source records attributed to L Silva.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Comparative evaluation of triamcinolone in coccidiosis control in fattening chickens].

The effectiveness of Triancinolone as a protector against coccidiosis in broilers was tested in a random design experiment. Cobb x Cobb one-day old chicken were assigned to the treatments: T1: no medication-no inoculation; T2: no medication-inoculation; T3: Triancinolone-inoculation; T4: Sodic Monensin-inoculation; and T5: Sodic Salinomycin-inoculation. The inoculation was accomplished with 10,000 oocysts of Eimeria tenella and 40,000 of intestinal Eimerias. The results of the intestinal damage degree showed that T3 (60.6%) and T4 (63.6%) were better to control coccidias in relation to T5 (96.9%) and T2 (100%). The oocysts number in feces (number/g) showed the best effectiveness for T3 (4,300) comparing with T4 (126,900), T5 (98,100), and T2 (382,000). These results emphasize the effective action mechanism of Triancinolone to interfere with the biological cycle of coccidias. The feed conversion was better (P < 0.05) in the groups that received the drugs (T3, T4, and T5) comparing with T2. This fact showed the adverse effect that coccidiosis cause on the broiler performance behavior. Triancinolone showed the best action effectiveness on the control of coccidiosis.

Animals↗
PubMed1997

[The absence of interference between GSM mobile telephones and implantable defibrillators: an in-vivo study. Groupe Systèmes Mobiles].

INTRODUCTION AND OBJECTIVES: The electromagnetic field created by mobile telephones can cause pacemaker dysfunction. Although implantable cardioverter defibrillators are also susceptible to electromagnetic interference, few studies have addressed this issue and compatibility with the GSM mode has not been tested. This study was developed to detect possible "in vivo" interference between GSM mobile telephones and implantable cardioverter defibrillators. MATERIAL AND METHODS: The study group is composed of 30 patients with 8 different models of defibrillators. Twenty six had endocardial leads and 4 epicardial. Three GSM mobile phones were used: Siemens S3 COM and Motorola 6200 in all cases and Ericsson GA 318 in one. The tests were performed under continuous electrocardiographic monitoring. All therapies were deactivated and sensitivities were set to maximal parameters. The telephones were positioned in close contact to the defibrillator can and precordium, in two different angles. Three situations were evaluated: calling, established contact for 15 seconds and ringing. The protocol was repeated during pacing to assess the possibility of pacemaker mode inhibition. RESULTS: No cases of electromagnetic interference were observed. One patient presented non-sustained ventricular tachycardia episodes during the tests that were detected by the defibrillator. CONCLUSIONS: These results suggest that electromagnetic interference by GSM mobile phones are not a probable cause of implantable defibrillators dysfunction.

Defibrillators, Implantable↗
PubMed1997

Termination of obligate anoestrus and induction of fertile ovarian cycles in dogs by administration of purified pig LH.

The potential role of LH in the initiation of the follicular phase in dogs was investigated by treating anoestrous bitches with highly purified pig LH (n = 16) or saline (n = 8) three times a day for 7 days, beginning in either early anoestrus (days 94-116 of the cycle) or mid-anoestrus (days 124-145). Treatment with LH induced pro-oestrus within 7 days (n = 16), and oestrus (n = 12) and fertile ovulations (n = 7) at 16 + 3 days, while pro-oestrus in bitches treated with saline did not occur until 46-166 days after the start of treatment. Six of the seven ovulating bitches whelped normal litters. The bitches in which pro-oestrus but not oestrus occurred were all treated in early anoestrus. During treatment, plasma oestradiol in bitches treated with LH increased from 8 + 2 pg ml-1 to 20 + 5 pg ml-1 within 1 day, and reached higher peak values (45 + 7 pg ml-1) (P < 0.05) than those observed in saline-treated controls (9 + 3 ng ml-1). These results demonstrate that LH treatment alone can terminate anoestrus by inducing a normal follicular phase in dogs. The results also suggest that, in normal cyclic bitches, anoestrus is the result of insufficient LH secretion, and that spontaneous pro-oestrus could be the result of increased LH secretion in the presence of already adequate concentrations of FSH.

Analysis of Variance↗
PubMed1997

Fluoride uptake in situ after the use of dental floss with fluoride.

The possibility of having a commercial product such as waxed floss with an additional agent for controlling and preventing caries is promising. The aim of this research was to determine the uptake of fluoride on tooth enamel in situ after the utilization of a dental floss with fluoride incorporated into the wax. One hundred blocks of bovine enamel were artificially demineralized and randomly separated into a Control Group (C) and a Test Group (T). The dental blocks in group T were mounted two-by-two simulating proximal contacts and were fixed into intra-oral lower arch devices. Eight volunteers with a similar salivary flow and buffer capacity wore devices with the enamel blocks for eight days. During this period of time the subjects applied a 25 cm long portion of a mint waxed floss with fluoride (0.15 mgF/m, Oral-B) between the blocks, 3 times a day for 2 minutes after each meal. At the same time, brushing was carried out with a fluoride-free toothpaste. The alkali-soluble fluoride (CaF2) formed on the enamel was extracted using the Caslavska et al. method and measured with the Orion 96-09 electrode-specific and the EA 720 ion analyzer. The results showed that the group that had the most CaF2 on the enamel (median, minimum and maximum in microF/cm2) was Group T (3.00, 2.11 and 4.00), which differed significantly (p < 0.01) from group C (0.26, 0.10 and 0.69). It was concluded that fluoride uptake on enamel was 11.54 times higher after use of dental floss with fluoride in this study.

Adult↗
PubMed1995

Variations in estimates of Guatemalan infant mortality, vaccination coverage, and ORS use reported by different sources.

All available estimates of rates of infant mortality, vaccination coverage (for BCG, DPT 3, polio 3, measles, and tetanus toxoid), and ORS use in Guatemala in the 1980s were identified and investigated. A large number of sources and estimates were found. Large discrepancies were also found between the estimates for a given indicator, even when the estimates were reported for the same year by the same source. For instance, reports for 1985 yielded 10 different infant mortality estimates ranging from 56.0 to 79.8 deaths per 1,000 live births; vaccination coverage estimates ranging from 30% to 60.5% for BCG, 3.5% to 34.2% for DPT 3, 3.5% to 33.5% for polio 3, 11% to 58.2% for measles, and 1% to 8.2% for tetanus toxoid; and estimated use rates of oral rehydration solution ranging from 3.5% to 7.2%. In this same vein, three Guatemalan Ministry of Health estimates of infant deaths per 1,000 live births in 1984 ranged from 52.4 to 79.8; four UNICEF estimates for 1985 ranged from 65 to 79.8; and three USAID estimates for 1987 ranged from 59 to 72. The many reasons found for this diversity point to significant problems influencing the reliability of current data.

Child, Preschool↗
PubMed1995

Changes of serum lipids in vitamin K3 (menadione) treated rats.

The effect of high doses of vitamin K3 (10 to 50 mg/kg/day of menadione, administered intramuscularly) on the serum content of total lipids, cholesterol, phospholipids and triglycerides in male Wistar rats was evaluated. This experimental group was compared with another group that received intramuscular injections of 10 to 50 mg/kg/day of sodium bisulphite. Hypervitaminosis K3 was diagnosed by jaundice (due mainly to unconjugated bilirrubin) and by anemia which was particularly evident at doses of 40 and 50 mg/kg/day of menadione. These doses of menadione increased serum content of total lipids, phospholipids, and triglycerides but decreased cholesterol. The results show that overdoses of vitamin K3 alter lipid metabolism. The influence o participation of liver damage, fastening, as well as various endocrine and hematological changes are considered responsible for the alterations in serum lipids.

Animals↗
PubMed1994

A controlled trial of pulse cyclophosphamide versus pulse methylprednisolone in severe lupus nephritis.

We carried out a prospective randomized trial comparing pulse cyclophosphamide and pulse methylprednisolone in 29 patients with severe lupus nephritis in activity. Patients were assigned to one of two regimens: monthly pulse cyclophosphamide (0.5-1.0 g/m2 body surface area) for 4 months, followed by bimonthly doses for 4 months and quarterly doses for 6 months (14 patients) or pulse methylprednisolone (10-20 mg/kg weight) initially for 3 consecutive days and thereafter in the same intervals as the alternative regimen (15 patients). The mean follow-up was 15 months. Two patients in the cyclophosphamide group and three in the methylprednisolone group died. Renal failure (doubling of serum creatinine) developed in four patients in the cyclophosphamide group compared with five patients in the methylprednisolone group. Cumulative probability of not doubling serum creatinine was similar for cyclophosphamide and methylprednisolone groups (0.66 vs 0.69, respectively, P > 0.20, after 18 months). Cumulative probability of survival without renal failure was also not significantly different (0.61 and 0.63, respectively, P > 0.20, after 18 months). These results suggest that pulse cyclophosphamide is as effective as pulse methylprednisolone in preserving renal function in patients with severe lupus nephritis.

Adult↗
PubMed1994

[Use of tranexamic acid for bleeding control in myocardial revascularization].

PURPOSE: To compare two groups of 80 patients undergoing to myocardial revascularization with the use of antifibrinolytic drug tranexamic acid and its efficacy in reduce bleeding and blood transfusion. METHODS: Prospective analysis of two groups of 80 patients. Group A-no antifibrinolytic therapy (dec 91-may 92) and group B-fibrinolytic therapy-tranexamic acid-10g EV (jun-dec/92). Quantification of mediastinal drainage over 12h as well as the blood or derivatives received at the same time. RESULTS: Hospital mortality: group A-3.8%, group B-2.5%. Drainage (12h): group A-602 +/- 547 ml and group B-260 +/- 260 ml (p < 0.001). Blood transfusion (12h): group A-1,782 +/- 1,163 ml and group B-1,105 +/- 839 ml (p < 0.001). COMPLICATIONS: group A-two cases of intraoperative myocardial infarction, one episode of jaundice; group B-one case of intraoperative MI, one reoperation for bleeding control, one episode of jaundice, one of renal insufficiency, two mediastinitis and one seizure. The mean hospitalization time was ten days in both groups. CONCLUSION: Tranexamic acid was an effective drug in bleeding control and in reducing blood transfusion in the postoperative of patients submitted to myocardial revascularization.

Adult↗
PubMed1992

Electrophysiological effects of atracurium and vecuronium on normal and denervated hearts.

Atracurium and vecuronium offer some advantages with respect to other nondepolarizing muscle relaxants. However, their administration has been associated with episodes of bradycardia and asystole, the mechanism of which has not yet been clarified. In an effort to analyze the effects of these drugs on automaticity, refractoriness, and conduction, 30 dogs underwent heterotopic heart transplantation to establish a model in which a normal heart (recipient) and a denervated heart (donor) could coexist. The electrophysiological studies included the determination of cycle length (CL), sinoatrial conduction time (SACT), antegrade and retrograde atrio-ventricular (A-V) node and ventricular block points (ABP and RBP), as well as effective antegrade and retrograde A-V node (ARPAVN and RRPAVN) and ventricular refractory periods (VRPs) in both hearts. These parameters were measured in a basal state and after injection of pancuronium (0.5 mg/kg) in 10 animals, atracurium (0.5 mg/kg) in another 10 dogs, and vecuronium (0.12 mg/kg) in the remaining animals. The results showed that pancuronium produced a tachycardia, significantly facilitated A-V conduction in the donor and the recipient hearts, and lowered the A-V node refractoriness in the donor organ, while atracurium and vecuronium induced no changes from the baseline values, either in normal or denervated hearts. Based on the results of this study, the episodes of sustained bradycardia reported in association with atracurium and vecuronium are attributed to the absence of antagonism of vagal stimuli provoked by pancuronium, and/or by surgical or anesthetic manipulations.

Animals↗
PubMed1992

Effect of fentanyl on cardiac automaticity and conduction: direct or mediated action?

The effects of fentanyl at a dose of 100 micrograms.kg-1 on cardiac automaticity, refractoriness and conduction have been studied in a model of heterotopic heart transplantation which combines a denervated heart (donor) and a non-denervated heart (recipient) in each of 20 dogs employed. Once the surgical procedure had been completed, cycle length, sinoatrial conduction time, antegrade and retrograde A-V node block points, cycle length at which 1:1 conduction ceases to exist and the antegrade effective refractory period of the A-V node and ventricles were measured. These parameters were determined in hearts both in the basal situation and 10 min after fentanyl injection. In the recipient organs, fentanyl produced statistically significant prolongation of cycle length, sinoatrial conduction time, antegrade block point and antegrade effective refractory periods of the A-V node and ventricles, with respect to the basal situation (P less than 0.01 for all these parameters); in 20% of cases, a complete A-V block was produced. In the donor hearts (denervated), prolongations of cycle length (P less than 0.01) and the antegrade block point (P less than 0.05), as compared with the basal situation, were recorded, but no other modifications were detected. To test whether these effects were due to the action of fentanyl, 10 animals were subsequently injected with naloxone, an agent which reverted the reported changes, although in the recipient organs, there persisted a slight prolongation of the cycle length with respect to basal measurements (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

A case-control study on the association of hepatitis B virus infection and hepatocellular carcinoma in northeast Brazil.

Hepatitis B virus (HBV) serological markers were investigated in 40 incident cases of hepatocellular carcinoma (HCC) and in two age and sex matched control groups, comprising 40 patients with other cancers and 80 healthy individuals, resident in Bahia, Brazil. Serologic tests were done by radioimmunoassay. The study observed high proportion of seropositivity to HBsAg (42.5%) and of those presenting HBsAg or antiHBc (65.0%) among HCC cases, higher in men than women and in those aged 17 to 30 years old. HBsAg seropositivity among HCC patients was greater than in the control group with other cancers (7.5%) and in healthy controls (2.5%), corresponding to odds ratio estimates of 15.0 (95% CI 3.29, 68.30) and 33.0 (95% CI 9.13, 119.28), both statistically significant. HBeAg was not observed and antiHBe was present in 41.2% of cases, suggesting the absence of viral replication, possibly with viral DNA integration into the hepatocyte genome. The presence of cirrhosis was associated with HBsAg seropositivity among HCC cases. A history of chronic alcoholism is shown to be more frequently related to those cases with cirrhosis. This study highlights the relevant association between HCC and HBV in Northeast Brazil, particularly for young individuals, and the high risk of development of HCC for HBsAg carriers.

Adolescent↗
PubMed1992

[Early and late results of myocardial revascularization after coronary thrombolysis with intravenous streptokinase in the treatment of acute myocardial infarction].

PURPOSE: To study the early and late results of patients treated initially intravenous streptokinase and then with coronary artery bypass surgery. METHODS: One hundred and twenty one patients with acute myocardial infarction less than 6 hours duration were treated initially with intravenous streptokinase, and 1-38 days after (median 8.80 days) coronary artery bypass was undertaken. Ninety six patients were operated with extracorporeal circulation and 25 without it. RESULTS: Overall operative mortality was 3.30% (4/121). Reoperations due to bleeding was necessary in 3.30% (4/121). Late mortality was 5.40% with survival probability of 94.60% after 36 months and 92.30% after 70 months. Late morbidity events in terms of angina and cardiac insufficiency demonstrated that 7 patients had angina, 4 cardiac insufficiency and two angina and cardiac insufficiency; probability to be free from these events was 88.20% after 46 months and 66.40% after 70 months. CONCLUSION: Coronary artery bypass surgery after intravenous streptokinase can be undertaken with security and excellent early and late results.

Adult↗
PubMed1990

Treatment of visceral leishmaniasis with pentavalent antimony and interferon gamma.

Acute visceral leishmaniasis is associated with an antigen-specific immunosuppression of mononuclear cells as evidenced by defective in vitro production of interferon gamma. We evaluated treatment with recombinant human interferon gamma in combination with conventional pentavalent antimony therapy in patients with visceral leishmaniasis. Six of eight patients with visceral leishmaniasis (mean duration, 17 months) that had been unresponsive to multiple courses of pentavalent antimony responded to treatment with recombinant human interferon gamma (100 to 400 micrograms per square meter of body-surface area per day) in addition to pentavalent antimony (20 mg per kilogram of body weight per day) for 10 to 40 days. The other two patients improved initially but then relapsed and required treatment with amphotericin B. Eight of nine additional patients with previously untreated severe visceral leishmaniasis were also successfully treated with the combination of interferon gamma and pentavalent antimony. The 14 patients who responded to this regimen had marked improvement in symptoms and in measures of anemia and leukopenia, as well as weight gain, a decrease in spleen size, and an absence or reduction of leishmanias in splenic aspirates. These patients had no recurrence of illness after a mean (+/- SE) follow-up of 8 +/- 1 months. Fever was the only major side effect of interferon gamma. We conclude that the combination of interferon gamma and pentavalent antimony is effective in treating seriously ill patients with refractory or previously untreated visceral leishmaniasis.

Adolescent↗
PubMed1990

Electrophysiology of heterotopic heart transplant: experimental study in dogs.

Electrophysiological properties were studied in a heterotopic heart transplant model developed in 44 dogs (Group I). Cycle length was 359.5 +/- 55.2 ms in the recipient heart and 500.9 +/- 77.9 ms in the donor heart (P less than 0.001). Sinoatrial conduction time was 38.6 +/- 13.6 ms in the recipient heart and 38.6 +/- 10.4 ms in that of the donor (not significant). The Wenckebach point was 175.4 +/- 31.1 ms in the recipient organ and 214.3 +/- 42.6 ms in the donor heart (P less than 0.001). The retrograde block point was 271.6 +/- 48.0 ms in the recipient heart and 353.6 +/- 47.3 ms in that of the donor (P less than 0.01). The effective antegrade refractory period was 133.4 +/- 28.7 ms in the recipient heart and 167.3 +/- 46.3 ms in the donor organ (P less than 0.001). An epicardial atrial cartography was performed at 44 preset points in both hearts, revealing a normal activation sequence and delays of 36-98 ms (mean 58 ms) in the recipient heart and from 39 to 59 ms (mean 50 ms) in the donor heart (not significant). In another 11 dogs (Group II), the same electrophysiological study was carried out under basal conditions and after pharmacological blockade of the autonomic nervous system with atropine (0.04 mg (kg body weight)-1) and propranolol (0.2 mg (kg body weight)-1). No significant differences were found in any of the parameters studied upon comparison of Group II animals in basal conditions with Group I recipients, and Group II dogs after blockade with Group I donors. These results demonstrate that the differences in automatism, conduction and refractoriness between the donor and recipient hearts are not attributable to differences in the haemodynamic situation or in the anaesthetic technique, but to denervation.

Animals↗