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Biomedical subjects

R R Silva

Publications and source records attributed to R R Silva.

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

Aortic reconstruction with crimped bovine pericardial conduits.

BACKGROUND AND AIM OF THE STUDY: A bovine pericardial conduit processed in glutaraldehyde was designed, incorporating the principle of crimping used for synthetic vascular prostheses. The crimping process did not affect the integrity of collagen fibers and tissue structure. This conduit, designed for aortic reconstruction, is available in different sizes, with or without a biological valve. METHODS: Between October 1989 and May 1997, 40 patients with aortic dissection, aortic aneurysm, aortic coarctation or aortoiliac occlusive disease underwent aortic reconstruction using this vascular substitute. Procedures included total reconstruction of the ascending aorta and aortic valve with reimplantation of coronary arteries (nine patients), single ascending thoracic aorta (six), descending thoracic aorta (two), aortic arch (one) and thoracoabdominal aorta (one); the abdominal aorta was reconstructed in 21 cases, including those undergoing aortoiliac or aortofemoral bypass. RESULTS: The hospital mortality rate was 20% (eight patients); causes of deaths were low cardiac output, recurrence of aortic dissection, multiple organ failure and bleeding. Mean follow up was 3.6 years; total follow up was 114 patient-years. Late conduit-related complications occurred in four patients, including a limb obstruction in one patient subjected to aortofemoral bypass and infection of three resulting in pseudoaneurysm (incidence of 3.5 +/- 1.8% per patient-year). All underwent reoperation. There were four late deaths due to sudden death, coronary artery disease, pneumonia and metabolic complications of diabetes and renal failure (incidence of 3.5 +/- 1.8% per patient year). The eight-year actuarial survival rate was 63.7 +/- 11.6%, including hospital mortality, and the eight-year actuarial freedom from conduit failure due to primary tissue structural degeneration was 100%. CONCLUSIONS: The crimping design provides a circular tube which makes construction of the anastomosis easier, retains its shape with bending, and avoids kinking. The material is very soft, easy to handle and suture, coapts nicely to suture lines resulting in a hemostatic anastomosis. The eight-year follow up demonstrated a satisfactory performance without report of fibrosis, calcification or aneurysmal dilation.

Animals↗
PubMed1997

An enzyme-linked immunosorbent assay (ELISA) that discriminates between the venoms of Brazilian Bothrops species and Crotalus durissus.

Enzyme-linked immunosorbent assays (ELISAs) were developed to detect specific antigens from Bothrops sp. and Crotalus durissus snake venoms in Brazil. Cross-reactive immunoglobulins from hyperimmune horse anti-Bothrops and anti-Crotalus sera were removed by immunoaffinity chromatography. Specific IgGs for Bothrops sp. and C. durissus venom antigens were prepared and used to set up a sandwich-type ELISA. The specificity of the assay was demonstrated by its capacity to identify correctly the circulating antigens in mice experimentally inoculated with both venoms. Measurable absorbance signals were obtained with 5 ng of venom per assay. The ELISA was also used to identify circulating antigens in the sera of humans bitten by Bothrops sp. and C. durissus. These ELISAs could be valuable for clinicians and epidemiologists if they prove to have both the high sensitivity and specificity required for such tests.

Animals↗
PubMed1997

Mitoxantrone, fluorouracil, and L-folinic acid in anthracycline-pretreated metastatic breast cancer patients.

In this phase II trial we have evaluated the activity and toxicity of a combination regimen containing mitoxantrone, L-leucovorin, and fluorouracil in patients with advanced breast cancer pretreated with anthracyclines. Forty-six patients were included into the study; they received a total of 227 cycles of chemotherapy. Median age was 63 years (range 34-78), median performance status was 80 (range 60-100). Visceral metastases were present in 37 patients, 6 patients had bone involvement only, while 3 patients had soft tissue/lymph node disease. Median number of previous chemotherapy regimens for advanced disease was 2 (range 1-3). Ten patients had anthracycline primary resistance (progressive disease during treatment). Twenty-three patients received mitoxantrone 12 mg/sqm day 1; fluorouracil 370 mg/sqm and L-folinic acid 100 mg/sqm days 1-3 administered every three weeks. Another group of 23 patients were treated with the same regimen using a prolonged 5FU/L-FA schedule (5 days). Two complete responses and 6 partial responses were recorded with the 3-day schedule; 7 partial responses in the 5-day schedule (overall response rate 32.6%, 95% C.I. 19-46%). Two partial responses were observed in patients with anthracycline primary resistance. Median response duration was 9 months (range 3-16). Hematologic toxicity was mild: grade 3-4 leukopenia was recorded in 5 patients, grade 3-4 thrombocytopenia in 3 patients. Grade III-IV stomatitis and diarrhea was recorded in 4 and 5 patients respectively (all receiving the 5-day 5-FU/L-FA schedule). Cardiac toxicity was observed in two cases. This regimen proved active in advanced breast cancer following anthracycline-containing chemotherapy, and the 3-day schedule could be offered to such patients with acceptable toxicity.

Adult↗
PubMed1997

Risperidone in children and adolescents with pervasive developmental disorder: pilot trial and follow-up.

Dopamine receptor antagonists, particularly haloperidol, have been the most effective medications in currently available double-blind placebo-controlled studies for treating the disruptive behaviors often associated with pervasive developmental disorder (PDD). The rationale for trying risperidone in this population includes its dopamine-blocking activity; its seemingly lower incidence of tardive dyskinesia when compared to standard neuroleptics; the possibility that risperidone may ameliorate the social withdrawal of PDD, as it does the negative symptoms in schizophrenia; and substantial effects on serotonergic neurotransmission, which has been shown to be dysregulated in some patients with PDD. This study was an open-label pilot trial of risperidone in 6 subjects (aged 7-14 years, mean = 10.7) who met DSM-III-R criteria for a PDD diagnosis. The mean optimal dose was 2.7 mg daily (range 1-6). Mean duration of risperidone administration was 5.2 months (range 1-8). Despite the small sample size, risperidone treatment appeared to be associated with significant improvements in ratings of angry affect (p = 0.04) and lability of affect (p = 0.03) and with a trend (p = 0.10) toward a reduction of mean hyperactivity scores. Clinical Global Improvement scale ratings were statistically significant (p < 0.001). Increased sociability was reported in 3 subjects by their parents and family following the study. Three patients continued on risperidone for over 2 years, and none showed any loss of its apparent therapeutic effects. Weight gain was observed in 5 of 6 patients, with a median increase of 5.4 kg (12 lbs) in 7 weeks. Other side effects included transient sedation, increased salivation, and stereotypies. One child showed a worsening of pre-existing tic and phobic symptoms after 5 months of successful monotherapy. No loss of therapeutic effect was noted in the 3 subjects who remained on risperidone for over 2 years, but 1 patient developed hepatotoxicity and another developed withdrawal dyskinesia, similar to her prior experience with haloperidol. Overall, 5 of the 6 patients derived significant clinical benefits from risperidone. Pharmacologic alternatives for treating behavioral symptoms in PDD are need, and risperidone may be a promising possibility.

Adolescent↗
PubMed1997

Intensive weekly chemotherapy for advanced gastric cancer using fluorouracil, cisplatin, epi-doxorubicin, 6S-leucovorin, glutathione, and filgrastim: a report from the Italian Group for the Study of Digestive Tract Cancer.

PURPOSE: A multiinstitutional trial was performed to confirm the clinical activity, in terms of response rate and toxicity (primary objectives) and duration of responses and survival (secondary objectives), of an intensive weekly regimen in advanced gastric cancer. PATIENTS AND METHODS: Patients with measurable unresectable and/or metastatic gastric carcinoma received 1-day per week administration of cisplatin (CDDP) 40 mg/m2, fluorouracil (5FU) 500 mg/m2, epi-doxorubicin (epi-ADR) 35 mg/m2, 6S-stereoisomer of leucovorin 250 mg/m2, and glutathione 1.5 g/m2. On the other days, filgrastim was administered by subcutaneous injection at a dose of 5 mg/kg. One cycle of therapy consisted of eight 1-week treatments. Patients who showed a response or stable disease received a further 6 weeks of therapy. RESULTS: Of 105 enrolled patients, 11 had locally advanced unresectable disease only; 33 had primary nonresected and metastatic disease; 48 had metastatic disease and primary tumor resected; 10 had locoregional recurrence and metastatic disease; and three had locoregional recurrence only. After one cycle, 18 complete responses (CRs) and 47 partial responses (PRs) were achieved, for an overall response rate of 62% (95% confidence interval [CI], 53% to 71%). Twenty patients had stable disease and 20 progressed on therapy. The median survival duration of all 105 patients was 11 months, with 1- and 2-year survival rates of 42% and 5%, respectively. World Health Organization (WHO) grade III to IV toxicity, in terms of anemia, neutropenia, thrombocytopenia, and mucositis, was experienced by 40 patients (38%). There were no treatment-related deaths. CONCLUSION: These data support the results of the pilot study and confirmed the high activity of the regimen, with acceptable toxicity. This schedule deserves evaluation in the adjuvant setting.

Adult↗
PubMed1996

Granisetron plus dexamethasone in moderately emetogenic chemotherapy: evaluation of activity during three consecutive courses of chemotherapy.

In this study we evaluated the antiemetic activity of a combination of 3 mg granisetron in a short i.v. infusion followed by 12 mg dexamethasone i.v. in 64 patients with cancer receiving moderately emetogenic chemotherapy scheduled in a single day. No patient had previously undergone chemotherapy and three consecutive cycles were evaluated. Response to antiemetic treatment was graded as follows: complete response, no episodes of vomiting; major response, only one episode; minor response, two to four episodes; failure, more than four episodes. Nausea was graded as absent, mild, moderate or severe (patients bedridden). At the first cycle a complete protection from acute vomiting and nausea was achieved in 95% and 73% of patients respectively; the rate of complete response for delayed vomiting was 90%, while 45% of patients complained of delayed nausea. The antiemetic and antinausea efficacy remained substantially unchanged during the second and third cycles of chemotherapy. Constipation and headache were the most frequent adverse events. In conclusion this antiemetic regimen appears very effective in preventing nausea and vomiting in moderately emetogenic chemotherapy.

Adult↗
PubMed1996

Carbamazepine use in children and adolescents with features of attention-deficit hyperactivity disorder: a meta-analysis.

OBJECTIVE: In the United States approximately 750,000 children receive psychostimulants to treat attention-deficit hyperactivity disorder (ADHD); up to 25% may not respond. The purpose of this study was to evaluate the reports in the international literature concerning the efficacy of carbamazepine (CBZ) in children with ADHD features by means of meta-analysis. METHOD: A review of the world literature located 29 reports that dealt with behavior problems, activity levels, and CBZ in children. Of these, only 10 reports provided sufficient or pertinent information for the meta-analysis. RESULTS: In all seven open studies, therapeutic responses were significant (ranging from p = .05 to .0001, two-tailed t test). Meta-analysis using weighted variables revealed a significant positive correlation (r = .88; p < .02) between duration of treatment and positive outcome. In three double-blind placebo-controlled studies, treatment effects for CBZ's superiority over placebo ranged from p = .07 to .0001. A meta-analysis of these three studies revealed that CBZ was significantly (p = .018) more effective than placebo at controlling target symptoms. CONCLUSIONS: Despite the general lack of attention that CBZ has received for treating ADHD, there is preliminary evidence that CBZ may be an effective alternate treatment in children with features of ADHD.

Anticonvulsants↗
PubMed1996

Causes of haloperidol discontinuation in patients with Tourette's disorder: management and alternatives.

BACKGROUND: Neuroleptics are considered the mainstay of treatment in Tourette's disorder, and haloperidol is deemed the treatment of choice by many. Factors such as treatment efficacy and the side effects that appear in response to neuroleptic administration have been implicated in affecting medication compliance. However, a detailed evaluation of these factors has yet to be undertaken in Tourette's disorder. METHOD: Of 51 consecutive referrals to a Tourette's disorder clinic, 48 met DSM-III-R criteria for Tourette's disorder. Of these 48, 28 had previously received neuroleptics. In this set of 28 patients, 24 (16 male, 8 female) had initially received treatment with haloperidol, and they made up the present sample; their ages ranged from 10.4 to 47.9 years (mean = 27.1), and age at onset ranged from 2 to 16 years. Each patient completed an evaluation consisting of a Tourette Syndrome Questionnaire and a clinical interview with the patient and involoved family members. Charts were also reviewed to gather information concerning side effects and other factors that led to haloperidol discontinuation and/or noncompliance. RESULTS: Duration of treatment ranged from 3 days to 14 years (mean = 3.6 years). In this sample, 12.5% (3/24) of the subjects continued medication without interruption (mean +/- SD = 8.4 +/- 5.1 years of medication). Of the 21 patients who discontinued haloperidol, 66.7% (14/21) did so because they experienced intolerable side effects, 9.5% (2/21) because of the fear of experiencing certain side effects, and 14.3% (3/21) because of a combination of these factors. The principal side effects that led to discontinuation included dysphoric reactions, akathisia, nervousness, sedation, dystonic reactions, and cognitive dulling/feeling drugged. CONCLUSION: Careful monitoring of side effects and efficacy is essential to continued compliance with haloperidol. In addition, psychoeducation about potential consequences of medication administration may help promote compliance in those patients who develop fears of possible adverse reactions.

Adolescent↗
PubMed1995

Environmental factors and related fluctuation of symptoms in children and adolescents with Tourette's disorder.

The purpose of this paper is to assess how 29 different environmental factors affected Tourette symptomatology in 14 children and adolescents (6.6-14.5 years; mean 10.3) who had never received any medication for their disorder. Assessment was based on patients' responses to the Tourette Syndrome (TS) Questionnaire. Eleven different factors were associated with a decrease in symptoms and included doctor visits, talking to friends, and reading for pleasure. The 10 factors reported to have no impact on Tourette symptomatology included various foods, weather, and living away from home. Seventeen factors associated with an increase in Tourette symptoms included events causing anxiety, emotional trauma, and social gatherings.

Adolescent↗
PubMed1995

Lithium in hospitalized aggressive children with conduct disorder: a double-blind and placebo-controlled study.

OBJECTIVE: To assess critically the efficacy and safety of lithium and replicate earlier findings in a larger sample of aggressive children with conduct disorder and to assess the utility of the Profile of Mood States (POMS) in this population. METHODS: Children hospitalized for treatment-refractory severe aggressiveness and explosiveness and with diagnosed conduct disorder were subjects in this double-blind, placebo-controlled clinical trial. After a 2-week placebo baseline period, children were randomly assigned to lithium or placebo treatment for 6 weeks of placebo. The main outcome measures were the Global Clinical Judgments (Consensus) Scale, Children's Psychiatric Rating Scale, Conners Teacher Questionnaire, Parent-Teacher Questionnaire, and the POMS. RESULTS: Fifty children (mean age 9.4 years) completed this study. The mean optimal daily dose of lithium was 1,248 mg and the mean serum level was 1.12 mEq/L. Lithium was superior to placebo, although the effects on some measures were more modest than in a previous study. CONCLUSIONS: Lithium appears to be an effective treatment for some severely aggressive children with conduct disorder. Although the POMS appeared to be reliable, it did not detect any response to lithium.

Aggression↗
PubMed1995

Renal effect of gentamicin in diabetic rats.

To evaluate the protective effect of diabetes mellitus (DM) on renal function of rats treated with gentamicin (GM), male Wistar-EPM rats (250-350 g) were treated with streptozotocin (SZ; 45 mg/kg) and starting 10 days after induction of diabetes, GM was given for ten consecutive days at a daily dose of 40 mg/kg. In the GM-treated group (G), a significant fall in inulin and sodium-p-amino-hippurate clearance was obtained (3.57 +/- 0.16 and 12.59 +/- 0.61 ml min-1 kg-1 vs 6.43 +/- 0.21 and 17.98 +/- 0.47 ml min-1 kg-1 in control rats (C), respectively) while in the animals previously injected with SZ (diabetic+gentamicin, DG group) these changes were not observed. The diabetic (D), G and DG groups showed a significant rise in urinary flow compared to C (0.165 +/- 0.009, 0.145 +/- 0.007 and 0.173 +/- 0.009 ml min-1 kg-1 vs 0.109 +/- 0.003 ml min-1 kg-1, respectively); however, only in G was the U/P inulin ratio significantly decreased when compared to C. The fractional excretion (FE) of sodium and potassium was significantly augmented in G when compared to C, D and DG. Thus, diabetes protected against gentamicin nephrotoxicity at both the glomerular and tubular level, although it did not promote a reduction in urinary flow.

Analysis of Variance↗
PubMed1994

A new pictorial instrument for child and adolescent psychiatry: a pilot study.

A pictorial instrument was developed to assess psychopathology in children aged 6 to 16 years. Symptom pictures (n = 137) representing DSM-III-R criteria were organized into seven diagnostic subscales. Clarity of the pictures was assessed in 31 normal children. Fifty-one psychiatric inpatient children completed the instrument using a 6-point visual analogue scale. Sensitivity to change was assessed in 15 children. The subscales' internal consistencies (Cronbach's alpha) ranged from 0.54 to 0.86. A canonical discriminant analysis among four diagnostic groups achieved a Wilks' lambda of 0.67 (p = 0.02). This instrument may be a valuable adjunct to psychiatric interviews in children.

Adolescent↗
PubMed1993

Mitomycin C, 5fluorouracil and folinic acid in combination with alpha 2b interferon for advanced colorectal cancer.

AIMS AND BACKGROUND: This study was conducted to investigate the activity and toxicity of 5fluorouracil folinic acid+mitomycin C combined with alpha 2b interferon in advanced colorectal cancer based upon recent studies suggesting a possible biochemical modulation of 5fluorouracil by interferon. PATIENTS AND METHODS: Between June 1990 and April 1991 25 previously untreated patients with advanced colorectal carcinoma were treated with mitomycin C 10 mg/m2 iv bolus on day 1, 5fluorouracil 375 mg/m2 on days 1 to 4 and folinic acid 200 mg/m2 on days 1 to 4 every 4 weeks, combined with alpha 2b interferon 3 million U day continuously. RESPONSE: Of the 25 patients entered into the study, 20 were evaluable for response as 5 patients withdrew due to toxicity (grade 3-4 thrombocytopenia in 4 cases and fatigue in 1). No complete response was recorded, 6 patients had partial remission (30%; 95% confidence interval, 10% to 50%), 4 experienced no change and 10 showed progressive disease. The toxicity of this regimen was significant, particularly myelosuppression. CONCLUSIONS: This combination showed a significant toxicity and low response rate compared with other 5fluorouracil based regimens in advanced colorectal cancer.

Aged↗
PubMed1993

Plasma beta-endorphin levels, naltrexone, and haloperidol in autistic children.

Plasma beta-endorphin levels were measured in 13 autistic children, aged 3.67 to 11.67 years at the end of treatment (naltrexone, haloperidol, pimozide, or placebo) and in 5 of the 13 children also at baseline. Baseline plasma beta-endorphin levels were lower than those reported in the literature. There was a strong correlation between plasma beta-endorphin levels and severity of sterotypies in all children. Naltrexone did not seem to have a specific effect on plasma beta-endorphin levels; short-term haloperidol treatment was associated with an increase, whereas long-term haloperidol treatment seemed to have a depressive effect on plasma beta-endorphin levels, which rose after withdrawal of haloperidol.

Autistic Disorder↗
PubMed1993

Haloperidol withdrawal and weight changes in autistic children.

The long-term effects of haloperidol on weight were assessed in 30 children, 25 males and 5 females, diagnosed with autistic disorder whose ages ranged from 3.08 to 8.42 years. They received haloperidol (0.25-3.50 mg/day; mean 1.26 +/- 0.84) for 6 months followed by a 4-week drug withdrawal period. Weights obtained on the last day of the 6-month haloperidol period were compared to weights obtained following drug withdrawal. There was no significant difference between the mean weights obtained on the last day of haloperidol administration (24.799 +/- 9.741 kg) compared to the mean weights at the end of the fourth week of the placebo period (24.644 +/- 9.833 kg). Weights increased during the first week of drug discontinuation (24.879 +/- 9.855 kg), but decreased during each following week of drug withdrawal. Weight was measured monthly during the 6-month haloperidol treatment period for 8 of the 30 subjects. In this subsample, weight gain was greater during the 1-month period lasting from the end of the 4-week drug withdrawal to the end of the first month after resuming haloperidol treatment than weight gain prior to drug withdrawal, between the fifth and sixth month of haloperidol treatment.

Autistic Disorder↗
PubMed1992

Side effects associated with lithium and placebo administration in aggressive children.

This study represents a secondary data analysis of two double-blind and placebo-controlled clinical trials of lithium, performed to contrast side effects associated with lithium administration to those associated with placebo. The sample consisted of 91 hospitalized children, aged 5.12 to 12.92 years (mean 9.16), diagnosed as having conduct disorder characterized by severe aggressiveness and explosiveness. Daily doses of lithium ranged from 250 to 2100 mg. During the entire treatment period, more side effects were seen in the lithium group than in the placebo group, whereas during the therapeutic dose period, the difference between side effects in the two groups diminished. The most common side effects seen exclusively with lithium administration included enuresis, fatigue, and ataxia. Increased aggressiveness was observed in 4 children who received placebo. Vomiting, headache, and stomachache were the most common side effects experienced by patients in both lithium and placebo groups. However, more patients experienced these side effects in the lithium group than in the placebo group.

Aggression↗