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Biomedical subjects

A Brown

Publications and source records attributed to A Brown.

At least 631 records · Page 35Linked to original sources
PubMed1978

Ex-patient visitors to the hospital psychiatric unit.

An informal study of visits to an inpatient psychiatric unit by former patients indicated that such visiting was a common occurrence, more prevalent than staff realized. Most ex-patient visitors were chronically impaired individuals who were making a marginal community adjustment and did not use aftercare services. Of 29 expatient visitors, some of whom made multiple and even daily visits, more than half appeared to use the visits as an indirect, symbolic way of asking for help. For some the brief contacts with treatment personnel seemed to have therapeutic value. The authors suggest that, although such visits may be troublesome to staff, expatient visitors should be welcomed and offered informal brief supportive contacts when feasible.

Adult↗
PubMed1978

Successful medical therapy for endocarditis due to Candida parapsilosis. A clinical and epidemiologic study.

A heroin addict with asymmetric septal hypertrophy and persistent fungemia with Candida parapsilosis was treated with amphotericin B and flucytosine (5-fluorocytosine). The diagnosis of endocarditis was based on the subsequent development of a murmur of mitral regurgitation and echocardiographic evidence of prolapse of the posterior leaflet of the mitral valve. Cure was effected with antifungal therapy alone. Thus, when the diagnosis of fungal endocarditis is made early in its course, open-heart surgery may not be needed. To investigate the relative frequency of isolation of C parapsilosis from particular sites, a mycologic survey was conducted in our hospital. Among the isolates of yeasts, C parapsilosis represented 8.0, 17.1, and 26.7 percent of those from all cultured sites, from contaminated intravenous catheters, and from cultures of blood, respectively. Since this trend to cluster in cases of fungemia was not seen with other yeasts, C parapsilosis appears to be more invasive than other species of Candida.

Adult↗
PubMed1978

Juvenile fibromatosis with invasion of the mandible: report of two cases.

Two cases of juvenile fibromatosis involving the mandible were found in children aged 1 1/2 and 2 1/2 years. The tumors, while histologically benign, were clinically aggressive, causing bone erosion and destruction and invading adjacent normal soft tissue structures with firm fibrous tumor extensions. In each instance, the lesion was completely removed by radical local surgery with no recurrence after a seven-year follow-up. The pertinent literature, consisting of six previously reported cases, has been reviewed.

Child, Preschool↗
PubMed1978

Endemic Serratia marcescens in the Veterans Administration Hospital in Pittsburgh, Pa., 1971--1976.

The incidence of infections due to Serratia marcescens increased steadily at the Veterans Administration Hospital in Pittsburgh, Pennsylvania from 1970 to mid 1975 followed by a decline extending into 1977. One hundred eighty-four Serratia marcescens isolates were collected from 123 patients over a 4-month period in 1975 and were characterized by stereotype and antibiotic sensitivity. Three-fourths of the isolates were clinically significant. Among 24 stereotypes O-:H2 predominated in the urinary tract and O-H12 in respiratory secretions. Clusters of serotypes were on occasion identified in the GU Surgery Ward and the Intensive Care Unit. Uninary isolates showed remarkable resistance to antibiotics; only two thirds were susceptible to amikacin, the most effective agent in vitro. The patients from whom Serratia was isolated were older than the general hospital population (60 vs. 53.6 years of age), were hospitalized longer than the age-corrected controls (62 vs. 34.5 days) and two-thirds of thirds of them acquired the infection in the hospital. Uninary catheterization and prior antibiotic therapy were significant risk factors for urinary infections, and prior surgery contributed to recovery of Serratia from the respiratory tract. Serotype and antibiotype differences between isolates from the urinary and those from the respiratory tract suggest that strains evolved a site specificity.

Anti-Bacterial Agents↗
PubMed1977

Pathogenesis of temperature-sensitive mutants of Sindbis virus in the embryonated egg. III. Autologous, homologous, and heterologous interference.

Two temperature-sensitive (ts) mutants of Sindbis virus able to synthetize RNA, but not two ts mutants defective in viral RNA synthesis, reduced to lethality of the superinfecting heat-resistant parent strain of Sindbis virus in embryonated chicken eggs as compared with results in controls. Autologous interference (of mutant with parent) was observed under a variety of conditions. Time-course studies in one selected system showed that lower titers of superinfecting parent virus were detected in doubly infected eggs than in controls eggs infected with only parent virus. Homologous interference with lethality (of mutant with an immunologically different yet related group A togavirus) was observed when the interfering virus was a ts mutant of either Sindbis virus or Eastern equine encephalitis virus. Heterologous interference (mutant with unrelated virus) could also be demonstrated with a ts mutant of Sindbis virus against vaccinia virus-induced pock formation or death. In an autologous interference experiment, in which the ts mutant of Sindbis virus was administered by the yolk sac route and the egg was challeged with parent heat-resistant Sindbis virus by the allantoic route, an interferon-like substance was found in the allantoic fluids at the time of challenge. It is concluded that certain ts viruses of togavirus group A can induce autologous, homologous, and heterologous viral interference in vivo.

Animals↗
PubMed1977

Antibody-dependent, complement-mediated homologous and cross-cytolysis of togavirus-infected cells.

The appearance of viral induced antigen(s) on Sindbis and Semliki Forest (SF) virus-infected chick embryo cells is detected with homologous mouse anti-viral antibody-dependent, complement-mediated cytolysis in a 51Cr release assay. Such antigen(s) is detected within 3 to 4 hr after infection whereas viral cytopathologic effects do not occur until 10 to 12 hr. In addition, significant heterologous cytolysis (anti-Sindbis on SF virus-infected cells, or, anti-SFV on Sindbis-infected cells) could be observed with serum samples tested. These sera were assayed for neutralizing and hemaggluatination-inhibition activities. Heterologous cytolysis cannot be correlated with hemagglutination-inhibition antibody titers nor is cross-neutralizing antibody detected. The possibility is discussed that another previously undefined antigen on infected cell membranes may be involved in heterologous cytolysis.

Animals↗
PubMed1976

Hydrogen exchange at the amide group of reduced pyridine nucleotides and the inhibition of that reaction by dehydrogenases.

Stopped flow ultraviolet spectroscopy has been used to measure the rate of hydrogen exchange with solvent at the amide group of reduced nicotinamide nucleotide coenzymes. Several mechanisms for the exchange reaction are considered in the light of the kinetic data. Complex formation between the coenzyme and any of four dehydrogenases markedly slows the rate of hydrogen exchange. Hydrogen bond formation and/or hydrophobic interactions within these complexes are thought to be the reasons for the decreased rate of exchange.

Alcohol Oxidoreductases↗
PubMed1976

Genetic control of the immune response: ability of antigens of defined amino acid sequence to be recognized by the Ir-1 gene system.

Mice were injected with a series of (T,G)-A--L[poly (L Tyr, L Glu)-poly DL Ala)--poly (L Lys)]-like compounds with side chains of homogeneous sequences: T-A--L, GT-A--L, GGT-A--L, and TG-A--L. T-A--L was not immunogenic. However, T-A--L was able to bind antibodies to (T, G)-A--L 509, and this binding could not be blocked by A--L. When complexed with bovine serum albumin, T-A--L, was immunogenic in both responder and nonresponder strains of mice. GT-A--L and GGT-A--L were both immunogenic and elicited the characteristic responder-nonresponder difference induced by (T,G)-A--L. TG-A--L was also immunogenic, but there was considerable overlap in the response of responder and nonresponder strains. On the average, responder mouse serum had a slightly higher antigen-binding capacity than nonresponder mouse serum. In contrast to antibodies against GGT-A--L, antibodies against TG-A--L bound heterologous antigens poorly. These data, along with the results of other investigators, are consistent with the hypothesis that there are multiple Ir- 1 genes which recognize different sequences. The specificity of the Ir- 1 genes is extraordinary. The polypeptides TG-A--L, TGTG-A--L and GTTG-A--L do not appear to be recognized by these genes.

Alanine↗
PubMed1976

Variants of the HR strain of Sindbis virus lethal for mice.

We have selected two similar variants of Sindbis HR virus which are lethal for mice. Consecutive brain to brain passage series were conducted in suckling and weanling mice. Specific anti-Sindbis HR neutralization tests and protection tests demonstrate that these viruses are derived from the parent Sindbis HR.

Animals↗
PubMed1976

Intrauterine transfusion in the management of severe rhesus isoimmunization.

In the ten years between 1965 and 1974, 2227 patients with rhesus isoimmunization were seen at the Newcastle centre. The antibody titre and previous history were the basis on which patients were selected for amniocentesis and determination of the amniotic fluid bilirubin ratio. There were 288 patients with a bilirubin ratio which was greater than 1-1: of these 206 were treated by intrauterine transfusion (IUT). Evidence for the belief that the treated and untreated groups were similar is presented. The overall survival rates were 44 per cent for cases treated by intrauterine transfusion and 50 per cent for those not treated in this way. The mortality directly attributable to the procedure was at least 20 per cent and did not take into account errors of selection nor accidents associated with amniocentesis.

Amniotic Fluid↗
PubMed1976

Renal extraction of gentamicin in anesthetized dogs.

The tubular handling of gentamicin (G) and its intrarenal distribution were determined to elucidate the mechanism of G accumulation in the kidney. At a serum level of 11.1 +/- 0.5 mug/ml (10 animals), as maintained by constant infusion for 5 h, serum Na(+) and K(+), arterial pressure, effective renal plasma flow and glomerular filtration rate remained undisturbed. The clearance values in milliliters per minute for G, inulin, and p-aminohippuric acid were 40.3 +/- 1.8, 49.9 +/- 2.8, and 132 +/- 14, respectively. The ratio of clearance of G to clearance of inulin was 0.82 +/- 0.04 (P < 0.005), suggesting net reabsorption of G by the renal tubules. The renal cortex/serum ratio for G was 11.9 +/- 2.1, and the medulla/serum ratio was 2.7 +/- 0.4, indicating greater uptake of G by the cortex. The extraction ratio of p-aminohippuric acid was 0.74 +/- 0.03. In contrast, the extraction ratio of G was 0.20 +/- 0.03, which was significantly lower than that of inulin (0.30 +/- 0.04). It is concluded that the accumulation of G in the cortex was due to tubular reabsorption. Probably some of the reabsorbed G became trapped in the epithelial cells after crossing the luminal membrane, whereas some returned to the circulation.

Animals↗
PubMed1976

Genetic evidence for a product of the Fv-1 locus that transfers resistance to mouse leukemia viruses.

Extracts of mouse cells have been shown to transfer to N- or B-trophic host range types of mouse leukemia viruses. The genetic specificity of the inhibition was tested in two ways: (i) by correlating the Fv-1 genotype of a number of mouse strains with the restriction-transferring activity of extracts of the respective embryo cell cultures, and (ii) by correlating the Fv-1 genotype of BLC3F2 (C57BL/6 female [Fv-1bb] by C3H male [Fv-1nn] parental strains) mouse embryos, which segregate the Fv-1 alleles in a 12:1 ratio, with the inhibitor activity of extracts of the cells from each embryo. Five independent matings, totaling 45 individual embryos, were tested. Each embryo was cultured, and the Fv-1 genotype was determined independently by titration of N- and B-tropic viruses; the extracts of replicate secondary cultures were tested for their effect on infection of permissive cells by N- and B-tropic viruses. The specific-restriction-transferring activity of the embryos was found to segregate with the appropriate Fv-1 genotype. These res-lts confirm the suggestion that the inhibitor of the leukemia virus host range types in the cellular extracts is a product of the Fv-1 locus.

AKR murine leukemia virus↗