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Biomedical subjects

J Silva

Publications and source records attributed to J Silva.

At least 163 records · Page 9Linked to original sources
PubMed1994

[Oculomotor paralysis. The perspective of a neuro-ophthalmology consultation].

Ocular paresis is a usual diagnosis in neuro-ophthalmologic consultation, and its aetiology is indeed a challenge. The authors studied 3400 records concerning this consultation, between 1982 and the third quarter of 1993. During this period 221 cases with ocular paresis were selected. During this retrospective study we point out the following items: the cranial nerve affected; the neuro-ophthalmologic semiology; the aetiology and clinical evolution, according to the age groups. From 221 cases selected, 111 were paresis from the VIth pair (50.2%), 88 from the IIIrd pair (39.8%), 14 multiple paresis (6.4%) and 8 paresis from the IVth pair (3.6%). The most frequent complaint was diplopia (> 90%). As far as the aetiological diagnosis is concerned, this was easier to establish in patients > 50 years of age. In this age group the most usual aetiology was vascular and traumatic pathologies. In younger patients the most frequent pathologies were traumatic and tumoral. The prognostic was better in the vascular group, the paresis recovery being > 50% in all other pathologies, except the tumoral one.

Adolescent↗
PubMed1993

Correlation between computed tomography and voltage and current source density spectral EEG parameters in patients with brain lesions.

In a group of patients with space-occupying brain lesions, CT measurements were correlated with absolute power (AP) and relative power (RP) of the delta, theta, alpha and beta EEG bands, calculated from the raw EEG potentials (EEGp) and from the Laplacian estimates also called "current source densities" (CSD). Rank correlations were calculated between the number of abnormal values in each band and the following CT measures: volume of the lesion and of the edema, density of the edema, percentage of ventricular collapse and midline shift. Abnormal spectral values are those which are significantly higher than the norm for the same age, in the delta and theta bands, and significantly lower in the alpha and beta bands. Spectral parameters obtained from the CSD showed higher correlations with CT measures than those calculated from the EEGp. In the Laplacian, all CT measures had a significant correlation with delta AP. Theta AP was significantly correlated with the volume and density of the edema, as well as with midline shift. Significant correlations were also observed with delta and alpha RP. However, changes in RP were considered to be a consequence of the increase in delta AP. Canonical correlation analyses between AP and RP calculated from EEGp or CSD and the first 3 CT measures showed that the volume of the lesion was only correlated with delta AP and RP. The volume and density of the edema showed a significant correlation with delta, theta and alpha AP calculated from EEGp and only with theta and alpha AP in the Laplacian. Since the EEGp tends to produce a more extensive and diffuse picture of abnormality, whereas the Laplacian acts as a spatial filter emphasizing local sources over distant sources, we concluded that edema is related not to delta activity, but to the theta and alpha power.

Adolescent↗
PubMed1993

Diagnosis and monitoring of Clostridium difficile infections with the polymerase chain reaction.

Toxigenic Clostridium difficile is the etiologic agent of pseudomembranous colitis. We have developed an assay system for the rapid direct detection of toxigenic C. difficile in human stool samples. After DNA extraction, polymerase chain reaction (PCR) amplification is undertaken with primers targeting specific sequences in the C. difficile 16S rRNA gene. Next, toxigenic strains of C. difficile are distinguished from nontoxigenic strains by PCR amplification of toxin A and/or B gene sequences. This study included 12 patients with C. difficile colitis, seven of whom had clinical relapses after discontinuation of vancomycin therapy. We detected toxigenic C. difficile in stools from four (57%) of these seven patients before relapse--at a time when no toxin B was detectable in stools and results of anaerobic culture were negative. The PCR assay is 100-fold more sensitive than anaerobic culture methods. The course of the infection in one patient (both during and after therapy) was monitored by the PCR technique. The multigene analysis approach permitted the detection of colonization with a nontoxigenic strain when this patient's relapses had cleared. This clinically applicable assay allows earlier detection of infection with toxigenic C. difficile. The result is more timely therapeutic intervention.

Aged↗
PubMed1993

Specific detection of toxigenic strains of Clostridium difficile in stool specimens.

Clostridium difficile is the infectious agent responsible for antibiotic-associated colitis. We report the use of the polymerase chain reaction technique to identify toxigenic strains of C. difficile in human stool specimens. A set of primers based on the nucleotide sequence of the toxin B gene, which amplified a 399-bp fragment from isolates producing toxin B, was designed. We examined 28 known toxigenic strains, which were all positive by this assay. DNAs from the nontoxigenic strains examined and from strains of Clostridium sordellii and C. bifermentans were not amplified with these primers. The sensitivity of this assay allowed us to identify as little as 10% toxigenic C. difficile cells in the presence of 90% nontoxigenic cells and to detect the toxin B gene in 1 pg of DNA from a toxigenic strain. DNAs extracted from 18 clinical stool specimens that were positive for toxin B by the tissue culture cytotoxicity assay were also positive by this assay. In addition, we detected toxin B sequences in DNA from 2 of 18 stool specimens that were negative for toxin B by the cytotoxicity assay. These two stool specimens were from patients who had a clinical pattern of colitis that was compatible with C. difficile causation. This rapid, sensitive assay will be useful for specific identification of toxigenic C. difficile and for revealing cases that are undetected by analysis of fecal samples for toxin B alone.

Bacterial Proteins↗
PubMed1993

Mollaret's meningitis associated with herpes simplex type 2 infection.

We describe three patients with benign recurrent aseptic meningitis (Mollaret's meningitis). For one of these cases, the episodes of meningitis were associated with herpetic outbreaks. Mollaret cells, which are a hallmark of Mollaret's meningitis, were present in the CSF from two of the three patients. In all cases, herpes simplex virus type 2 DNA was present in the CSF during the acute illness as detected by polymerase chain reaction amplification, although viral cultures from CSF were all negative. Herpesviruses, notorious for frequent and sporadic recurrence, are ideal candidates for the cause of Mollaret's meningitis.

Adult↗
PubMed1993

[Percutaneous valvuloplasty in congenital aortic valve stenosis].

PURPOSE: To show the initial experience of Institute of Cardiology of Rio Grande do Sul in the treatment of congenital valvular aortic stenosis with percutaneous balloon aortic valvuloplasty. METHODS: Twenty four patients were submitted to the procedure, 14 males and 10 females. The mean age 7 years (4 days-17 years). Four patients were aged below 30 days and three patients had previous surgical valvuloplasty. The percutaneous balloon aortic valvuloplasty were made the retrograde approach in all patients. RESULTS: The peak systolic pressure gradient was reduced from 65.96 +/- 22.68 to 27.08 +/- 18.74 mmHg. The procedure resulted in aortic regurgitation in seven patients and worsened aortic regurgitation in two patients. One patient had cardiac arrest that was reverted by cardiopulmonary resuscitation, this patient had hospital discharge without sequel. Five patients had acute femoral artery thrombosis, and hemorrhage in the site of puncture happened in one patient. CONCLUSION: The percutaneous balloon aortic valvuloplasty results in effective reduction of the peak systolic pressure gradient, it is a save and effective therapy in patients with congenital valvular aortic stenosis. Further evaluation of the long term results are necessary for definitive conclusions.

Adolescent↗
PubMed1993

BCG vaccination protects against leprosy in Venezuela: a case-control study.

A total of 64,570 household and other close contacts of about 2000 leprosy cases were screened for eligibility for entry into a trial of a new leprosy vaccine. The screening procedure included a clinical examination for leprosy and for the presence of BCG and lepromin scars. Ninety-five new cases of leprosy were identified, and the prevalence of BCG and lepromin scars among them was compared with similar data from matched controls selected from among those with no evidence of leprosy. The difference in the prevalence of BCG scars in the two groups was used to estimate the protection against leprosy conferred by BCG vaccination. One or more BCG scars was associated with a protective efficacy of 56% (95% confidence limits 27% to 74%). There was a trend of increasing protection with four or more BCG scars, but this was not statistically significant. There was no evidence that the efficacy of BCG varied with age or according to whether or not the contact lived in the same household as a case. The protective effect was significantly higher among males, and was significantly greater for multibacillary than for paucibacillary leprosy.

Adolescent↗
PubMed1993

[Mucinous adenocarcinoma of the urachus. Apropos of a case].

This report present one case of mucinous adenocarcinoma of the urachus, a very uncommon tumour with eccentric clinical behaviour. It includes a brief description of both its macro and microscopic appearance, establishing the differential diagnosis both with adenocarcinoma of the vesical dome and the metastatic tumours which can affect the bladder. Also, there is a brief comment on the main anatomo-clinical characteristics of these tumours.

Adenocarcinoma, Mucinous↗
PubMed1992

Immunoprophylactic trial with combined Mycobacterium leprae/BCG vaccine against leprosy: preliminary results.

In an attempt to find a vaccine that gives greater and more consistent protection against leprosy than BCG vaccine, we compared BCG with and without killed Mycobacterium leprae in Venezuela. Close contacts of prevalent leprosy cases were selected as the trial population since they are at greatest risk of leprosy. Since 1983, 29,113 contacts have been randomly allocated vaccination with BCG alone or BCG plus 6 x 10(8) irradiated, autoclaved M leprae purified from the tissues of infected armadillos. We excluded contacts with signs of leprosy at screening and a proportion of those whose skin-test responses to M leprae soluble antigen (MLSA) were 10 mm or more (positive reactions). By July, 1991, 59 postvaccination cases of leprosy had been confirmed in 150,026 person-years of follow-up through annual clinical examinations of the trial population (31 BCG, 28 BCG/M leprae). In the subgroup for which we thought an effect of vaccination was most likely (onset more than a year after vaccination, negative MLSA skin-test response before vaccination), leprosy developed in 11 BCG recipients and 9 BCG/M leprae recipients; there were 18% fewer cases (upper 95% confidence limit [CL] 70%) in the BCG/M leprae than in the BCG alone group. For all cases with onset more than a year after vaccination irrespective of MLSA reaction the relative efficacy was 0% (upper 95% CL 54%; 15 cases in each vaccine group). Retrospective analysis of data on the number of BCG scars found on each contact screened suggested that BCG alone confers substantial protection against leprosy (vaccine efficacy 56%, 95% CL 27-74%) and there was a suggestion that several doses of BCG offered additional protection. There is no evidence in the first 5 years of follow-up of this trial that BCG plus M leprae offers substantially better protection against leprosy than does BCG alone, but the confidence interval on the relative efficacy estimate is wide.

BCG Vaccine↗
PubMed1992

Triage of patients out of the emergency department: three-year experience.

Because of severe emergency department (ED) overcrowding, the authors initiated a program of referring certain patients who were assessed as not needing emergency care away from the ED. A selected group of patients who presented to a busy university ED were refused treatment and triaged away following a medical screening examination performed by a nurse. In this 3-year study 136,794 patients presented to the triage area in the ED, of which 21,069 (15%) were refused care and referred elsewhere. Letters and calls to all referral clinics, eight local EDs, and the coroner's office identified no patients who had been grossly mistriaged, and only insignificant adverse outcomes could be identified. Additional follow-up on 3,740 individuals triaged away was performed by telephone. Responses from this survey indicated that 42% of persons received care elsewhere the same day, 37% within 2 days, and 22% decided not to seek medical care. A group of 1.6% sought care at other hospital EDs for minor complaints. The authors concluded that a group of patients can be selectively triaged out of the ED without significant adverse outcomes, which may offer one approach to the problem of ED overcrowding.

Adult↗
PubMed1991

A University of California State-supported AIDS research award program--a unique state and university partnership in AIDS research.

This article describes the State-supported University of California AIDS research award program and its major accomplishments. It shows how a partnership between a University and a State resulted in the formation of a successful, efficient, and cost-effective AIDS research award program. This program provides funds for rapid testing of investigator-initiated meritorious research ideas, new drugs, and treatment modalities. Funds were also utilized to establish three AIDS Clinical Research Centers, which evolved into regional consortia that coordinate trials of new drugs and other modalities. This program succeeded in involving investigators whose efforts have led to excellent medical care, advanced technologies, and new drugs for treating AIDS and AIDS-related diseases. The University remains committed to continuing support of all areas of AIDS research, emphasizing drug and vaccine development, pediatric AIDS, and AIDS prevention studies in groups at high risk for HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1991

The mechanism of action of a synthetic immunomodulator, 3,6-bis(2-piperidinoethoxy)acridine trihydrochloride (CL 246,738), in natural killer cell activation in animals.

CL 246,738 is a low molecular weight, synthetic immunomodulator. The present study was done to determine the interaction among interferon (IFN), macrophages, and natural killer (NK) cells in mice following oral administration of CL 246,738. Splenic NK activity as evidenced by lysis of YAC-1 lymphoma cells in vitro was found to be augmented by the compound not only in normal mice, but also in immunodeficient beige and nude mice. Lytic activity remained elevated from one to seven days after a single treatment and the peak activation varied depending on the source of NK cells. NK cell activity associated with the peritoneal exudate cell population peaked at day 1 and returned to normal by day 2, whereas NK cell activity of peripheral blood lymphocytes peaked at day 3 and remained significantly elevated until day 7. Liver associated NK activity peaked at day 4 and remained significantly elevated at day 7 after treatment with CL 246,738. Lung associated NK activity was elevated by day 1 after treatment, peaked at day 4 and returned to normal by day 7 after drug administration. The drug was also effective in inducing IFN in all mouse strains tested. When these drug-treated mice were given antibody to IFN-(alpha + beta) but not to IFN-(beta), both IFN levels and NK cell activity decreased, suggesting the importance of IFN-(alpha) in this system. Furthermore, mice that had received carrageenan prior to, but not after CL 246,738 administration showed reduced serum IFN titers as well as decreased NK cell activity, indicating that macrophages played an intermediate role in immune enhancement by the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Acridines↗
PubMed1991

Depression of cell-mediated immunity in plasmacytoma-bearing mice.

Previous reports have documented that mice bearing plasmacytomas (PC) are suppressed in their ability to mount a primary antibody response, whereas cellular immunity appears to be normal. Studies presented here provide evidence that T cell responsiveness is also depressed in BALB/c mice bearing the Lieberman plasmacytoma (Lpc-1). For instance, splenocytes from mice bearing large tumours were impaired in their in vitro ability to respond to the T cell mitogen, mount an appropriate alloreactive cytolytic T lymphocyte response, and produce interleukin-2 (IL-2). A population of suppressor cells was detected in the spleens 7 days after tumour implantation as evidenced by their ability to prevent normal splenocytes not only from responding to antigens in mixed lymphocyte culture, but also from producing IL-2. A similar inhibitory effect was observed with culture supernatants of these cells, indicating the existence of a soluble suppressive factor. Therefore, the present study demonstrates that cellular immune responses are impaired in mice bearing Lpc-1 tumours and that this effect may be due to the generation of suppressor cells and/or a suppressive factor.

Animals↗
PubMed1991

Birth of the first 100 babies in Hawaii after conception in-vitro: experience at the Pacific In-Vitro Fertilization Institute.

This paper reports on the first 100 infants delivered consecutively the result of 63 pregnancies after conception in-vitro at the Pacific In-Vitro Fertilization (IVF) Institute. These pregnancies were established prior to the introduction of embryo-cryopreservation into the program. Ninety-seven percent (97%) of singleton pregnancies delivered after 36 weeks; only 5/31 (16%) required tocolytic therapy. The overall multiple gestation rate was 51%, higher than in many other IVF centers. Maternal complications and neonatal morbidity were associated primarily with these multiple gestations. Forty-one percent (41%) delivered in less than 36 weeks, and tocolytics were administered in 22/27 (81%) of twin and 5/5 (100%) of triplet gestations. Neonatal morbidity was noted in 39 infants (33 from multiple gestations); 28 neonates were admitted to the intensive care unit (27 from multiple gestations). Nine births had or developed minor abnormalities (hernias, pyloric stenosis). One case of Trisomy 21, and one infant death at 11 months occurred in the group. The caesarean section rate for all IVF deliveries was 65%. It is concluded that IVF is clearly established in Hawaii for infertility refractory to other methods of treatment. The risk associated with IVF stem from the possibility of multiple gestations, not whether the pregnancy was initiated in-vitro. In the future, embryo cryopreservation may help to reduce the risk of multiple pregnancy.

Adult↗
PubMed1991

Relapsing polychondritis and Reiter's syndrome.

We describe a case of relapsing polychondritis associated with Reiter's Syndrome in a 46-year-old white man. Relapsing polychondritis is a rare disorder of unknown etiology associated in about 30% of cases with other rheumatic disorders such as connective tissue diseases, vasculitis and exceptionally, seronegative spondyloarthritis. We found this association only once in our review of the literature.

Arthritis, Reactive↗
PubMed1990

Health status of Air Force veterans occupationally exposed to herbicides in Vietnam. I. Physical health.

The Air Force Health Study is a 20-year comprehensive assessment of the health of Air Force veterans of Operation Ranch Hand, the unit responsible for aerial spraying of herbicides in Vietnam. The study compares the health and noncombat mortality of Ranch Hand veterans with a comparison group of Air Force veterans primarily involved with cargo missions in Southeast Asia but who were not exposed to herbicides. This report summarizes the health of these veterans as determined at the third in a series of physical examinations. Nine hundred ninety-five Ranch Hands and 1299 comparison subjects attended the second follow-up examination in 1987. The two groups were similar in reported health problems, diagnosed skin conditions, and hepatic, cardiovascular, and immune profiles. Ranch Hands have experienced significantly more basal cell carcinomas than comparison subjects. The two groups were not different with respect to melanoma and systemic cancer.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1990

Toxicity of nitrobenzene compounds towards isolated hepatocytes: dependence on reduction potential.

1. The cytotoxicity of p-substituted nitrobenzenes towards isolated hepatocytes under aerobic or hypoxic conditions has been determined. The nitrobenzene concentration required to cause 50% cytoxicity in 2 h was a function of the one-electron reduction potential of the nitrobenzene, with the more cytotoxic compounds having the strongest electron-withdrawing substituents. 2. The effectiveness of the nitrobenzenes at causing cytotoxicity under aerobic but not hypoxic conditions was markedly increased if hepatocyte catalase was inhibited with azide. 3. Nitrobenzenes at cytotoxic concentrations induced cyanide-resistant respiration in isolated hepatocytes. Their effectiveness correlated with their cytotoxicity. 4. The rate of oxygen activation of these nitrobenzenes by ascorbate was also a function of the one-electron reduction potential. The nitro compounds with the strongest electron-withdrawing substituents were the most rapidly reduced. 5. Most nitrobenzenes were more cytotoxic under aerobic than hypoxic conditions. Ascorbate enhanced hypoxic, but not aerobic, cytotoxicity. 6. It was concluded that the cytotoxicity of different nitrobenzenes is related to their ease of reduction to nitro radical anions and nitrosobenzenes. Aerobic cytotoxicity is probably initiated by redox cycling and oxygen activation by the nitro radical anions whereas hypoxic cytotoxicity is probably initiated by the alkylation of macromolecules by nitrosobenzene metabolites.

Alkylation↗