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Biomedical subjects

J A Hale

Publications and source records attributed to J A Hale.

7 recordsLinked to original sources
PubMed2001

The independent cue and cus systems confer copper tolerance during aerobic and anaerobic growth in Escherichia coli.

Copper is essential but can be toxic even at low concentrations. Coping with this duality requires multiple pathways to control intracellular copper availability. Three copper-inducible promoters, controlling expression of six copper tolerance genes, were recently identified in Escherichia coli. The cue system employs an inner membrane copper transporter, whereas the cus system includes a tripartite transporter spanning the entire cell envelope. Although cus is not essential for aerobic copper tolerance, we show here that a copper-sensitive phenotype can be observed when cus is inactivated in a cueR background. Furthermore, a clear copper-sensitive phenotype for the cus system is revealed in the absence of O(2). These results indicate that the cue pathway, which includes a copper exporter, CopA, and a periplasmic oxidase, CueO, is the primary aerobic system for copper tolerance. During anaerobic growth, however, copper toxicity increases, and the independent cus copper exporter is also necessary for full copper tolerance. We conclude that the cytosolic (CueR) and periplasmic (CusRS) sensor systems differentially regulate copper export systems in response to changes in copper and oxygen availability. These results underscore the increased toxicity of copper under anaerobic conditions and the complex adaptation of copper export in E. coli.

Aerobiosis↗
PubMed1995

Proposed criteria for interpretation of susceptibilities of strains of Neisseria gonorrhoeae to ciprofloxacin, ofloxacin, enoxacin, lomefloxacin, and norfloxacin.

The susceptibilities of 45 strains of Neisseria gonorrhoeae, including 25 strains susceptible to ciprofloxacin (MICs, < or = 0.06 microgram/ml) and 20 strains exhibiting decreased susceptibilities to ciprofloxacin (MICs, > or = 0.125 microgram/ml), to ciprofloxacin, ofloxacin, enoxacin, lomefloxacin, norfloxacin, and nalidixic acid were determined by agar dilution and disk diffusion. On the basis of theoretical calculations of predicted susceptibilities at which infections may fail therapy (supported by observed failures of infections to respond to the therapeutic doses of enoxacin and ciprofloxacin), the Centers for Disease Control and Prevention has adopted the following agar dilution breakpoints for interpretation of resistance to these agents: MICs of > or = 1.0 microgram of ciprofloxacin, enoxacin, and norfloxacin per ml and MICs of > or = 2.0 micrograms of ofloxacin and lomefloxacin per ml. The corresponding disk diffusion breakpoints for these agents were as follows: ciprofloxacin, < or = 29 mm; ofloxacin, < or = 24 mm; enoxacin, < or = 31 mm; lomefloxacin, < or = 26 mm; and norfloxacin, < or = 32 mm. The Centers for Disease Control and Prevention recommends two strains as interim quality control strains for susceptibility testing of ciprofloxacin and ofloxacin. These are N. gonorrhoeae CDC-10,328 (MIC of ciprofloxacin, 0.125 to 0.25 microgram/ml [inhibition zone diameter range, 30 to 34 mm]; MIC of ofloxacin, 0.5 microgram/ml [inhibition zone diameter range, 27 to 32 mm]) and N. gonorrhoeae CDC-10,329 (MIC of ciprofloxacin, 1.0 to 2.0 micrograms/ml [zone inhibition diameter range, 21 to 26 mm]; MIC of ofloxacin 2.0 micrograms/ml [inhibition zone diameter range, 18 to 21 mm]).

Anti-Infective Agents↗
PubMed1986

Improved graft patency associated with altered platelet function induced by marine fatty acids in dogs.

Female mongrel dogs fed a marine fish diet rich in long-chain polyenoic fatty acids had improved patency of small-diameter arterial prosthetic grafts as compared to controls. Also, in vivo platelet function as measured by bleeding times was significantly prolonged. Eicosapentaenoic acid, not found in the serum of control animals, was present in relatively high concentrations in both the serum and a platelet-rich fraction of the marine oil-fed group. Eicosapentaenoic acid, unlike arachidonic acid, does not induce platelet aggregation and this phenomonon may account for the altered platelet function demonstrated in our animals and hence the improved graft patency. These data lend further support to the role of platelets in determining the patency of vascular grafts.

Animals↗
PubMed1985

Tuberculosis of the breast: rare but still extant. Review of the literature and report of an additional case.

Tuberculosis of the breast is a rare malady that is usually manifested by a unilateral mass suggestive of carcinoma or sometimes of abscess. Mammography also suggests carcinoma in most instances. However, at operation, the discovery of necrotic tissue or abscess may lead to the suspicion of infectious or inflammatory disease rather than neoplasm. The diagnosis of tuberculosis may be established by the demonstration of acid-fast bacilli in excised tissue, by culture studies, or by guinea pig inoculation; however, the diagnosis is usually not suspected. In the past, mastectomy was the usual treatment. Today, successful treatment combines antituberculous drug therapy with the removal of infected breast tissue. The prognosis for complete cure is excellent. One case of secondary tuberculous mastitis has been reported herein. The patient, an Egyptian woman residing in the United States since 1973, was treated in Egypt for pulmonary tuberculosis at age 17. She presented in 1982 with a breast mass that mimicked carcinoma on physical examination and mammograms, but excisional biopsy and histologic examination revealed a breast abscess that contained caseous material and a solitary acid-fast bacillus. The patient was cured of her disease after appropriate operation and a course of antituberculous drugs. This has been the only documented case of mammary tuberculosis at our institution. Despite its rarity, tuberculosis of the breast should not be forgotten in this age of world travel.

Adult↗
PubMed1985

Chest wall masses in children.

A hard, fixed mass on the chest wall is usually considered to be malignant. Of 24 such lesions we have evaluated in children, only eight (33%) were malignant. Six of the eight children with malignant masses died of the disease. Benign lesions were often indistinguishable from malignant lesions by physical or roentgenographic examination, and histologic diagnosis was often difficult. Small lesions could be excised en bloc without significant deformity. Seven masses were the product of indolent infection, indicating that cultures should be obtained. Larger lesions should have adequate biopsy to direct the proper sequence of subsequent radical operation, irradiation, and chemotherapy. The defect created by radical operation is closed with polypropylene mesh and/or flap coverage. With this graded approach, the majority of children with chest wall lesions will survive with minimal deformity.

Adolescent↗
PubMed1979

Ineffectiveness of erythromycin for treatment of Haemophilus vaginalis-associated vaginitis: possible relationship to acidity of vaginal secretions.

To assess the efficacy of oral erythromycin in the treatment of nonspecific vaginitis (NSV), conducted a nonrandom, unblinded pilot study among 17 women with symptoms and signs of NSV. At the completion of treatment, 10 of 13 patients had persistent symptoms, 9 of 13 had persistent abnormal discharge, and 11 of 13 had persistently positive cultures for Haemophilus vaginalis. Ten patients with persistent or relapsing NSV and four who did not complete erythromycin treatment were retreated with oral metronidazole, and 14 of 14 showed clinical improvement and eradication of H. vaginalis. The susceptibility of 27 clinical isolates of H. vaginalis to erythromycin was determined at pH 5.5, 6.0, 6.5, and 7.0. The minimal inhibitory concentration of erythromycin for H. vaginalis was approximately 10-fold higher at pH 5.5 than at pH 7.0. Erythromycin is not effective for the treatment of H. vaginalis-associated NSV; this may be partly attributable to the reduced activity of this drug in acidic vaginal secretions.

Erythromycin↗