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Biomedical subjects

B Hall

Publications and source records attributed to B Hall.

At least 109 records · Page 6Linked to original sources
PubMed1987

Chloramphenicol-resistant Salmonella newport traced through hamburger to dairy farms. A major persisting source of human salmonellosis in California.

Animal-to-human transmission of drug-resistant salmonella and the role of antimicrobial use in food animals in the emergence of these bacteria are controversial subjects. Investigation of a 4.9-fold increase in Salmonella newport isolations from Californians in 1985 showed that 87 percent of the isolates had an unusual antimicrobial-resistance pattern (including chloramphenicol resistance) and a single, identical plasmid. Interviews of 45 patients and 89 matched controls in Los Angeles County showed that illness was associated with penicillin or tetracycline use during the month before onset (P less than 0.001) and with eating ground beef during the week before onset (P = 0.052). The epidemic strain was isolated from hamburger products eaten by cases, abattoirs where the animals from which the meat came were slaughtered, dairies that sent cows for slaughter on days when culture-positive products were processed, and ill dairy cows. Isolation of salmonella from beef carcasses in abattoirs correlated with the proportion of dead or moribund animals received for slaughter (r = 0.60, P less than 0.05). Isolation of chloramphenicol-resistant salmonella from dairy farms was associated with the use of chloramphenicol at those dairies. We conclude that food animals are a major source of antimicrobial-resistant salmonella infections in humans and that these infections are associated with antimicrobial use on farms.

Abattoirs↗
PubMed1987

Verapamil in essential hypertension: a comparison with atenolol plus hydralazine.

The effects of graded doses of verapamil were compared with those of a combination of atenolol and hydralazine in a double-blind, randomised, crossover trial in 16 patients with essential hypertension. During the placebo phase, mean arterial pressure (M.A.P.) was 123 +/- 17 mmHg. Verapamil (dose range 160-480 mg/day) lowered M.A.P. to 109 +/- 7 mmHg (p less than 0.01 vs placebo). The combination of atenolol (50-100 mg/day) and hydralazine (50-200 mg/day) lowered M.A.P. to 100 +/- 11 mmHg (p less than 0.001 vs placebo, p less than 0.05 vs verapamil). Neither regimen produced any deleterious effects on electrocardiographic intervals, echocardiographic indices of left ventricular function or plasma lipids. Verapamil was well tolerated and provided satisfactory alternative therapy in these patients with mild-to-moderate essential hypertension.

Adult↗
PubMed1987

Cardiovascular and behavioral responses of gray wolves to ketamine-xylazine immobilization and antagonism by yohimbine.

Adult wolves (Canis lupus) were immobilized with 6.6 mg/kg ketamine hydrochloride (KET) and 2.2 mg/kg xylazine hydrochloride (XYL) administered intramuscularly. Induction time was 4.6 +/- 0.3 min (mean +/- SE). Immobilization resulted in significant bradycardia and hypertension (P less than 0.05). Twenty min after induction, the wolves were given 0.05-0.60 mg/kg yohimbine hydrochloride (YOH). Yohimbine given intravenously produced dose-related increases in heart rate (HR) with doses greater than 0.15 mg/kg resulting in extreme tachycardia (greater than 300 bpm). All doses of YOH caused a temporary decrease in mean arterial blood pressure (MABP) with some individual animals manifesting profound hypotension (less than 30 torr) at doses greater than 0.15 mg/kg. Increasing the dose of YOH above 0.15 mg/kg did not significantly decrease either arousal or ambulation times. Administering YOH at 40 or 60 min after induction resulted in decreased arousal and ambulation times. Stimulation by weighing and taking repeated blood samples during anesthesia did not shorten arousal times. We recommend that wolves immobilized with XYL-KET be antagonized with doses of YOH less than 0.15 mg/kg.

Animals↗
PubMed1985

Colonic pseudo-obstruction: an uncommon complication of caesarean section.

Four cases of pseudo-obstruction following lower segment Caesarean section are presented with a review of the condition. In the first patient the diagnosis was made at laparotomy, but the other 3 were diagnosed on clinical and radiolographic grounds. Two of these subsequently required surgical caecal decompression, while only 1 was successfully managed conservatively. This is typical of the spectrum of this uncommon but well recognized syndrome which may complicate Caesarean section, vaginal delivery, hysterectomy or other gynaecological operations. When diagnosed, the initial management may be conservative, but close surveillance of caecal diameter must be maintained in order to prevent disastrous caecal rupture. When this is imminent, decompression by either colonoscopy, or laparotomy and caecostomy is indicated. With early surgical intervention, the high mortality rate for this condition can be greatly reduced.

Adult↗
PubMed1985

Cell-specific expression of secreted versus membrane forms of immunoglobulin gamma 2b mRNA involves selective use of alternate polyadenylation sites.

Immunoglobulin heavy chain genes encode at least two forms of mRNA, secretory- and membrane-specific. In less mature B cells and tumors arising from them, lymphomas, the membrane form of the protein and mRNA are in high abundance, while in more mature stages, plasma cells, and myeloma tumor cells, the secreted forms of protein and mRNA predominate. In myeloma cells producing approximately 8:1 ratios of secretory- to membrane-encoding forms of gamma-heavy chain mRNA, we observed equimolar transcription of the secretory- and membrane-encoding exons of the gene. In isolated nuclei from 4T001 (gamma 2b) and K23 (gamma 2a) myeloma cells, the secretory-encoding mRNA polyadenylation site was used at least three times as often as the membrane-encoding mRNA polyadenylation site. In the A20 (gamma 2a) lymphoma, which produces equal amounts of mature secretory- and membrane-encoding heavy chain mRNAs, results of experiments with isolated nuclei showed that the membrane mRNA polyadenylation site was used about two times as often as the secretory mRNA polyadenylation site. Selective use of alternate polyadenylation and cleavage sites, therefore, can modulate the production of the two mRNAs from a single gene during B cell differentiation.

Animals↗
PubMed1984

Patterns of adnexal inflammatory damage: Chlamydia, the intrauterine device, and history of pelvic inflammatory disease.

In a study of 204 consecutive infertile couples, 58 women with adnexal abnormalities consistent with prior pelvic infection were identified. The status of those 58 subjects with respect to prior pelvic infection, prior intrauterine device use, and serologic evidence of past chlamydial infection was correlated with the types of adnexal abnormalities identified. Women with serologic evidence of past chlamydial infection were more likely to exhibit severe adhesions and hydrosalpinx formation, and hydrosalpinx formation was related to a history of clinically detected pelvic infection.

Chlamydia Infections↗
PubMed1983

Studies on bile-salt-stimulated lipolytic activity in human milk. II Demonstration of two groups of milk with different activities.

Human milk samples were assayed for bile-salt-stimulated lipolytic activity in the presence of an unpurified and purified preparation of glycoconjugated bile salts and two patterns of activity were obtained. One group of milks (high activity) had similar activities (mean +/- 1 S.D.) of 16.9 +/- 3.5 (purified bile salts) and 17.2 +/- 3.5 mumole . ml-1 . h-1 (unpurified bile salts) whereas another group (low activity) had a lower activity with the purified (4.2 +/- 2.3 mumole . ml-1 . h-1) than with the unpurified bile salt preparation (19.9 +/- 4.0 mumole . ml-1 . h-1). Activities of the low activity milks (assayed with the purified bile salts) could be increased following storage at -20 degrees C, sonication, or the preparation of an acetone ether powder and, in some cases, reached the maximal activity obtained with the unpurified bile salt preparation. These procedures had no effect on the activity of the high activity milks. Recombination experiments, whereby the milk serum from a low activity milk was added to the milk fat of a high activity milk and vice versa, and also kinetic studies suggest that the differences in activities between the two groups result from differences in availability of the enzyme and are independent of the source of milk fat.

Bile Acids and Salts↗
PubMed1982

Intraoral insertion of grafts to project the nasal tip.

Certain tip-projecting techniques require insertion of grafts and/or implants into the premaxillary region. These grafts may extend anteriorly into the columella or may have to reach all the way to the tip to exert the projecting forces exactly where the surgeon wishes to have them applied. The most direct technique for insertion of these long grafts is one of the columella-splitting maneuvers, but some patients will not accept the external scarline necessitated. An intraoral approach can be used in these patients or in any others in whom the surgeon wishes to have no external scar. It allows good exposure, easy insertion of the grafts and/or implants, and secure closure for stabilization and fixation of the grafts.

Humans↗
PubMed1982

Surgical update on nasal dermoids.

A one-stage surgical procedure describing the removal of the necessary nasal bones for complete eradication of nasal dermoids, with subsequent replacement of the intact bones, is discussed herein. This technique has proved to be invaluable in two patients who underwent this procedure. Extensive meticulous dissection often is necessary to extirpate this cystic lesion to prevent its recurrence. Extensive surgery, however, need not result in a notable cosmetic deformity that requires secondary restorative measures. Using this technique, replaced nasal bone segments effect immediate reconstruction. A 20-year review of the cases of nasal dermoids from the Children's Hospital Medical Center, Boston, also is presented.

Child, Preschool↗