PubMed Health⌕ Search

Biomedical subjects

G Bolan

Publications and source records attributed to G Bolan.

At least 55 records · Page 3Linked to original sources
PubMed1986

Red man syndrome: inadvertent administration of an excessive dose of rifampin to children in a day-care center.

A cluster of toxic reactions among children inadvertently given excessive doses of rifampin for chemoprophylaxis of invasive Haemophilus influenzae disease in a day-care center was investigated. In all 19 children, who received five times the therapeutic dose of rifampin, dramatic adverse reactions developed. A striking, "glowing" red discoloration of the skin and facial or periorbital edema were found to be the hallmarks of rifampin toxicity. These clinical signs of acute toxicity contrast sharply with the adverse side effects of rifampin reported with therapeutic doses.

Acute Disease↗
PubMed1985

Infections with Mycobacterium chelonei in patients receiving dialysis and using processed hemodialyzers.

Between April and November 1982, 27 of 140 patients in a hemodialysis center in Louisiana were infected with rapidly growing mycobacteria; 14 had bacteremia alone, 3 had soft-tissue infections, 1 had an access-graft infection, and 9 had widely disseminated disease. Of 26 identified isolates, 25 were Mycobacterium chelonei ssp. abscessus, and one was an M. chelonei-like organism. One factor common to all patients was exposure to processed hemodialyzers (artificial kidneys). Environmental sampling of the water-treatment system showed widespread contamination with nontuberculous mycobacteria, which were also recovered from the patient's side (blood compartment) of five of 31 hemodialyzers that had been processed and were ready for use. The formaldehyde concentration was less than 2% in two of three such contaminated dialyzers tested. We hypothesize that patients became infected when their blood circulated through processed dialyzers that contained viable rapidly growing mycobacteria. This outbreak demonstrates that hemodialysis patients may be at risk for developing infections with rapidly growing mycobacteria and that such infections may go unrecognized when routine culture methods are used. It also emphasizes the importance of using effective procedures to disinfect dialyzers in hemodialysis centers.

Adult↗
PubMed1985

Acute bacterial meningitis in children and adults. A perspective.

Bacterial meningitis is an acute and serious illness associated with significant morbidity and mortality. Although methods to make the diagnosis are relatively simple and effective antimicrobial agents are available, bacterial meningitis accounts for more than 2000 reported deaths per year in the United States. The majority of cases and deaths occur in otherwise healthy individuals.

Adolescent↗
PubMed1984

Trans-isolate medium: a new medium for primary culturing and transport of Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae.

A diphasic medium, Trans-Isolate medium, was developed for the transport of primary cultures of cerebrospinal fluids from patients with bacterial meningitis. It consists of a charcoal-starch agar slant and soybean-casein digest-gelatin broth buffered at pH 7.2 with 0.1 M 3-(N-morpholino)propanesulfonic acid buffer. In the laboratory, this medium supported the growth and survival of stock cultures of Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae for at least 3 months. Under field conditions in Africa, cerebrospinal fluids from patients suspected of having bacterial meningitis were inoculated directly onto plates of chocolate agar medium and into bottles of Trans-Isolate medium. An etiological agent was isolated from 52 spinal fluids by direct plating. After shipment to Atlanta, Ga., 2 to 4 weeks later, the same etiological agents were recovered from 38 bottles of Trans-Isolate medium.

Bacteriological Techniques↗
PubMed1977

Effects of estrone, estradiol, and estriol on hormone-responsive human breast cancer in long-term tissue culture.

The effects of estrone, estradiol, and estriol on MCF-7 human breast cancer are compared. In this estrogen-responsive cell line, all three estrogens are capable of inducing equivalent stimulation of amino acid and nucleoside incorporation. Estriol is capable of partially overcoming antiestrogen inhibition with Tamoxifen (lCl 46474), even when antiestrogen is present in 1000-fold excess. Antiestrogen effects are completely overcome by 100-fold less estriol. Studies of metabolism of estrogens by MCF-7 cells revealed no conversion of estriol to either estrone or estradiol. All three steroids bind to a high-affinity estrogen receptor found in these cells. The apparent dissociation constant is lower for estradiol than for estrone and estriol, but all three bind to an equal number of sites when saturating concentrations are used. Tritiated estrogens used in binding studies were shown to be radiochemically pure. We conclude that estriol can bind to estrogen receptor and stimulate human breast cancer in tissue culture. Our data do not support an antiestrogenic role for estriol in human breast cancer.

Binding, Competitive↗
PubMed1976

Hormone responsive human breast cancer in long-term tissue culture: effect of insulin.

The mechanisms of steroid and peptide hormone action in human breast cancer are poorly understood. We have previously characterized a cell line of human breast cancer in long-term tissue culture that possesses various steroid hormone receptors and responses, providing a model for the study of steroid hormone action. The present studies describe a human breast cancer in vitro that responds to physiologie concentrations of insulin with an increased rate of macromolecular synthesis and growth. Thymidine and uridine incorporation in cells in serum-free medium are stimulated by 10(-11) M insulin and are maximal with 10(-8) M. Leucine incorporation is stimulated by 5 X 10(-11) M insulin and is maximal with 10(-9) M. Significant stimulation of uridine and leucine incorporation is evident by 3 hr and maximal by 10 hr. A 10-hr lag period exists for insulin stimulation of thymidine incorporation, which is maximal form 14 to 24 hr. The effect of 10(-8) M insulin on macromolecular synthesis is accompanied by a 69% increase above controls in the number of cells after 24 hr. The effect on macromolecular synthesis is observed in glucose-free medium. Insulin's effect on protein synthesis is not blocked by inhibition of RNA synthesis with actinomycin D. Glucocorticoids partially inhibit the action of insulin in these cells. This system provides a model for studying insulin action, and suggests that some human breast cancer may show growth regulation by insulin.

Breast Neoplasms↗
PubMed1976

The effects of estrogens and antiestrogens on hormone-responsive human breast cancer in long-term tissue culture.

We have established or characterized six lines of human breast cancer maintained in long-term tissue culture for at least 1 year and have examined these lines for estrogen responsiveness. One of these cell lines, MCF-7, shows marked stimulation of macromolecular synthesis and cell division with physiological concentrations of estradiol. Antiestrogens are strongly inhibitory, and at concentrations greater than 3 X 10(-7) M they kill cells. Antiestrogen effects are prevented by simultaneous treatment with estradiol or reversed by addition of estradiol to cells incubated in antiestrogen. Responsive cell lines contain high-affinity specific estradiol receptors. Antiestrogens compete with estradiol for these receptors but have a lower apparent affinity for the receptor than estrogens. Stimulation of cells by estrogens is biphasic, with inhibition and cell death at concentrations of 17beta-estradiol or diethylstilbestrol exceeding 10(-7) M. Killing by high concentrations of estrogen is probably a nonspecific effect in that we observe this response with 17alpha-estradiol at equivalent concentrations and in the otherwise unresponsive cells that contain no estrogen receptor sites.

Binding Sites↗
PubMed1976

The effects of glucocorticoids and progesterone on hormone-responsive human breast cancer in long-term tissue culture.

Glucocorticoids, at physiological concentration, inhibit cell division and thymidine incorporation in three lines of human breast cancer maintained in long-term tissue culture. At steroid concentrations sufficient to inhibit thymidine incorporation 50%, little or no effect is seen on protein synthesis 48 hr after hormone addition. All three of these lines are shown to have glucocorticoid receptors demonstrable by competitive protein binding assays. Receptors are extensively characterized in one line by sucrose density gradient analysis and binding specificity studies. Good correlation between receptor-binding specificity and biological activity is found except for progesterone, which binds to glucocorticoid receptor but is noninhibitory. Cross-competition and quantification studies demonstrate a separate receptor for progesterone. This receptor has limited binding specificities restricted largely to progestational agents, whereas the glucocorticoid receptor bound both glucocorticoids and progesterone. Two other human breast cancer lines neither contain glucocorticoid receptor nor are inhibited by glucocorticoids. It is concluded that in some cases glucocorticoids can directly limit growth in human breast cancer in vitro without requiring alterations in other trophic hormones.

Binding Sites↗
PubMed1976

The effects of androgens and antiandrogens on hormone-responsive human breast cancer in long-term tissue culture.

We have examined five human breast cancer cell lines in continuous tissue culture for androgen responsiveness. One of these cell lines shows a 2- to 4-fold stimulation of thymidine incorporation into DNA, apparent as early as 10 hr following androgen addition to cells incubated in serum-free medium. This stimulation is accompanied by an acceleration in cell replication. Antiandrogens [cyproterone acetate (6-chloro-17alpha-acetate-1,2alpha-methylene-4,6-pregnadiene-3,20-dione) and R2956 (17beta-hydroxy-2,2,17alpha-trimethoxyestra-4,9,11-triene-1-one)] inhibit both protein and DNA synthesis below control levels and block androgen-mediated stimulation. Prolonged incubation (greater than 72 hr) in antiandrogen is lethal. The MCF- cell line contains high-affinity receptors for androgenic steroids demonstrable by sucrose density gradients and competitive protein binding analysis. By cross-competition studies, androgen receptors are distinguishable from estrogen receptors also found in this cell line. Concentrations of steroid that saturate androgen receptor sites in vitro are about 1000 times lower than concentrations that maximally stimulate the cells. Changes in quantity and affinity of androgen binding to intact cells at 37 degrees as compared with usual binding techniques using cytosol preparation at 0 degrees do not explain this difference between dissociation of binding and effect. However, this difference can be explained by conversion of [3H]-5alpha-dihydrotestosterone to 5alpha-androstanediol and more polar metabolites at 37 degrees. An examination of incubation media, cytoplasmic extracts and crude nuclear pellets reveals probable conversion of [3H]testosterone to [3H]-5alpha-dihydrotestosterone. Our data provide compelling evidence that some human breast cancer, at least in vitro, may be androgen dependent.

Androgen Antagonists↗
PubMed1976

Interactions of antiestrogens with human breast cancer in long-term tissue culture.

A variety of antiestrogens can be shown to antagonize estrogen action in animal model systems. Several of these compounds are useful in the management of metastatic human breast cancer. To further elucidate their mechanism of action, we studied several of these compounds using human breast cancer cell lines maintained in long-term tissue culture as a model system. Antiestrogens including tamoxifen (NSC-180973; ICI-46474), nafoxidine. CI-628, and clomiphene citrate inhibit macromolecular synthesis below control levels in two human breast cell lines. This effect is limited to cell lines which contain estrogen receptors. Simultaneous addition of as little as 1000-fold less estradiol prevents antiestrogen effects. Sequential addition of estrogen for up to 48 hours to cells incubated in antiestrogen reverses inhibition. If cells are continued in antiestrogen alone for more than about 3 days, inhibitory effects become irreversible. The cells detach from the surface of the culture vessel and are no longer viable. Tamoxifen competes with 3H-estradiol for specific receptor sites but with about a 100-fold lower apparent affinity. Direct binding of 3H-tamoxifen and 3H-estradiol to duplicate cytoplasmic extracts reveals equivalent numbers of binding sites but a 20-fold lower affinity for the antiestrogen. There is reasonable agreement between concentrations of tamoxifen which bind to receptor and concentrations which inhibit cells.

Animals↗
PubMedDate not supplied

Self-reported childhood and adolescent sexual abuse among adult homosexual bisexual men.

From May 1989 through April 1990, 1,001 adult homosexual and bisexual men attending sexually transmitted disease clinics were interviewed regarding potentially abusive sexual contacts during childhood and adolescence. Thirty-seven percent of participants reported they had been encouraged or forced to have sexual contact before age 19 with an older or more powerful partner; 94% occurred with men. Median age of the participant at first contact was 10; median age difference between partners was 11 years. Fifty-one percent involved use of force; 33% involved anal sex. Black and Hispanic men were more likely than white men to report such sexual contact. Using developmentally-based criteria to define sexual abuse, 93% of participants reporting sexual contact with an older or more powerful partner were classified as sexually abused. Our data suggest the risk of sexual abuse may be high among some male youth and increased attention should be devoted to prevention as well as early identification and treatment.

Adolescent↗
PubMedDate not supplied

Evaluation of Syva's enzyme immunoassay for the detection of Chlamydia trachomatis in urogenital specimens.

A newly developed microwell enzyme immunosorbent assay (EIA) system by Syva Company (Palo Alto, CA) can detect Chlamydia trachomatis in < 3 hr. It uses a polyclonal antibody to chlamydial lipopolysaccharide and end points are determined with a spectrophotometer. Three clinical trial sites (University of California Medical Center, San Francisco, CA; University of Washington, Seattle, WA; and Louisiana State University Medical Center, New Orleans, LA), compared this EIA with tissue culture (TC) for identifying Chlamydia in urogenital specimens. Overall prevalence by TC was 10.4% (136 of 1306). When tests were compared with TC (using vials or microtiter plates and a fluorescent antibody stain), we found an EIA sensitivity of 93.4% (127 of 136) and a specificity of 98.1% (1148 of 1170). This EIA has a performance profile that is, at the very least, comparable with other nonculture methods for diagnosing genital tract infections with C. trachomatis.

Antibodies, Bacterial↗
PubMedDate not supplied

Evidence for school transmission of Neisseria meningitidis during a Vermont outbreak.

A meningitis outbreak due to Neisseria meningitidis, serogroup C, serotype 2b, occurred in central Vermont in February, 1984. The highest incidence was in Northfield, where 7 cases occurred (129 per 100,000 population). Of these 7 cases 2 were students at Northfield High School and 5 were younger children; all had had close contact with Northfield High School students or staff in the week before illness. A case-control study demonstrated that these cases had significantly more exposure to Northfield High School students or staff in the 2 weeks before illness (112 hours) than did controls (8 hours) (P = 0.006). This finding was confirmed by a second case-control study designed to determine risk factors for the entire outbreak. School children in Northfield and their household contacts were given meningococcal A-C vaccine and sulfisoxazole prophylaxis. No further cases of meningococcal disease occurred in Northfield after the week that these control methods were initiated. Transmission of the outbreak strain of N. meningitidis appears to have occurred in a school setting with subsequent illness in household and close contacts of carriers of the outbreak strain.

Adolescent↗
PubMedDate not supplied

Homosexual men who engage in high-risk sexual behavior. A multicenter comparison.

To describe homosexual men who continue to engage in unprotected oral and anal sex, 601 men who attended three urban STD clinics and who had engaged in these behaviors with a male partner in the previous 4 months were interviewed regarding their sexual and drug-use behaviors. Although approximately one fourth of participants had engaged in 1 to 2 episodes of unprotected anal sex, more than 20% reported engaging in greater than 23 episodes. Higher frequency of anal sex was associated with lower condom use rates. Although 50% had primary relationships, less than 22% had sex with just one partner, and less than 10% were in relationships concordant for HIV-antibody status. Multiple regression analyses showed that number of drugs used each month, sex in a steady relationship, and Hispanic ethnicity were the most consistent predictors of risk behavior across sites. Careful evaluation of the diverse nature and characteristics of these men is essential to target risk-reduction programs for this population.

Adult↗