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Biomedical subjects

M Gallagher

Publications and source records attributed to M Gallagher.

At least 199 records · Page 11Linked to original sources
PubMed1981

Opiate effects in the amygdala central nucleus on heart rate conditioning in rabbits.

Opiate agents were administered into the central nucleus of the amygdala complex of rabbits prior to either classical conditioning or pseudoconditioning of heart rate responding. Compared to control groups, opiate administration into the central nucleus did not significantly alter baseline heart rate, heart rate responding during habituation trials to presentations of the conditioned stimulus alone, or heart rate responding during the pseudoconditioning procedure. However, opiate administration altered the acquisition of a conditioned bradycardia response during classical conditioning trials in which the offset of the conditioned stimulus was coincident with the presentation of an aversive unconditioned stimulus. the opiate agonist levorphanol (5.0 nmole) significantly impaired the acquisition of the conditioned bradycardia response. This effect was observed to be stereospecific and blocked by concurrent administration of the opiate antagonist naloxone (2.5 nmole). Naloxone (2.5 nmole) administration alone significantly increased the magnitude of the conditioned bradycardia response. These effects produced by opiate administration into the central nucleus were not observed following administration of the same agents into sites 1-2 mm dorsal to the central nucleus.

Amygdala↗
PubMed1980

beta-Adrenergic manipulation in amygdala central n. alters rabbit heart rate conditioning.

The present study was conducted to assess the effects of beta-adrenergic manipulation within the central nucleus of the amygdala on Pavlovian heart rate conditioning in the rabbit. Administration of the beta-adrenergic antagonist dl-propranolol into the central nucleus impaired the acquisition of conditioned heart rate responding compared to a vehicle injected control group. No significant effects of dl-propranolol on either baseline heart rate or on the heart rate orienting response were observed. The effect of dl-propranolol on conditioning exhibited stereospecificity, and animals receiving combined intracerebral injections of dl-propranolol and the beta-adrenergic agonist 1-isoproterenol did not exhibit comparable conditioning impairments. In addition, dl-propranolol administration dorsal to the central nucleus or into amygdala sites anterior or posterior to the central nucleus was less effective. These results support the interpretation that beta-adrenergic activity within the central nucleus region of the amygdala complex contributes to the acquisition of classically conditioned heart rate responding.

Amygdala↗
PubMed1978

Respiratory syncytial virus infection. Rapid diagnosis in children by use of indirect immunofluorescence.

Specimens of 387 nasopharyngeal suction smears obtained from 354 children hospitalized with acute respiratory infections during an eight-month period were examined for the presence of respiratory syncytial (RS) virus by the indirect immunofluorescence antibody technique (IFAT) and by conventional tissue culture infectivity techniques. Respiratory syncytial virus was identified in nasopharyngeal suction smear specimens from 123 of these specimens (32%) with the use of both techniques. Of the specimens positive on tissue culture 92% were also positive for RS virus by IFAT. However, eight specimens positive for RS virus by tissue culture were negative by IFAT, although three of the specimens were technically unsuitable. Six percent of the specimens negative for RS virus by tissue culture were positive for RS virus antigen when tested by IFAT. Using IFAT, identification of RS virus could be accomplished within four to six hours, whereas isolation by tissue culture took an average period of ten days. These data suggest that IFAT is a reliable means for the rapid diagnosis of RS virus infection in infants and children.

Adolescent↗
PubMed1978

Use of the antibody assay in immunized mice for the determination of rabies vaccine potency.

At present, the NIH potency test is the most widely used method for determining the potency of rabies virus vaccines. The drawbacks of this test are well known and include significant test variability as well as the use of an unnatural challenge route. The antibody assay in immunized mice involves the assay of sera from mice immunized with serial dilutions of rabies vaccine. The amount of antibody in the sera is expressed in International Units per ml (IU/ml). Sera from identical dilutions of different vaccines are compared for potency with serum from the same dilution of U.S. Reference Rabies Vaccine. A "unit ratio" is calculated by dividing the serum potency value for the test vaccine by that for the reference vaccine at each dilution tested. This unit ratio may then be compared to the antigenic value generated by the NIH test performed on the same vaccines. In this study, results are reported for both duck embryo and human diploid cell culture vaccines using the Serum Neutralization Test in mice as well as the Rapid Fluorescent Focus Inhibition Test to assay the antisera. Correlations are presented between the unit ratio and antigenic value for all vaccines tested. Also, practical applications and limitations of the test are discussed.

Animals↗
PubMed1977

Memory formation: evidence for a specific neurochemical system in the amygdala.

beta-Adrenergic antagonists injected into the amygdala complex of rats trained in a passive avoidance task produced time-dependent and dose-dependent decreases in retention of the task. In addition, the effects observed with beta-adrenergic antagonists were both stereospecific and reversed by norepinephrine. The results support a role for an amygdala beta-adrenergic system in memory processes.

Adrenergic beta-Antagonists↗
PubMed1977

Penicillinase-resistant penicillins plus gentamicin in experimental enterococcal endocarditis.

Previous in vitro studies demonstrating that the penicillinase-resistant penicillins act synergistically in combination with gentamicin against some enterococci have suggested that these combinations might be effective therapy for enterococcal infections in vivo. To determine the in vivo effectiveness of such combinations, we treated rabbits with enterococcal endocarditis with gentamicin and either nafcillin, oxacillin, or methicillin. Despite doses of the penicillins equivalent to 12 or 24 g/day in a 70-kg patient, the percentage of animals in each treatment group with sterile valves at autopsy after spontaneous death or sacrifice after 21 days of therapy was low. High-dose therapy with the penicillins did not significantly increase survival over the low-dose treatment groups. Thus, it seems prudent to include penicillin with a penicillinase-resistant penicillin and gentamicin as the initial therapy of patients with endocarditis possibly caused by enterococci.

Animals↗
PubMed1977

Therapeutic use of gentamicin in horses: concentrations in serum, urine, and synovial fluid and evaluation of renal function.

Serum, synovial fluid, and urine concentrations of gentamicin were measured in normal mature horses which had been given a single dose of the drug. Mean peak serum concentration (16.8 microgram/ml) occurred in horses 30 minutes after they were given a single intramuscular dose of 4.4 mg of gentamicin/kg of body weight. In horses given a smaller dose of gentamicin (1.7 mg/kg), mean peak serum concentrations of gentamicin (10.2 microgram/ml) appeared at 1 hour. Synovial fluid concentration was maximum at 2 hours for both doses; in horses given the larger dose, mean peak concentration was 6.4 microgram/ml, and in those given the smaller dose (1.7 mg/kg), 3.4 microgram/ml. Measurable concentrations of gentamicin in serum and synovial fluid persisted 8 hours. During the first 8 hours, percentages of gentamicin excreted in the urine were between 3.9 and 32.8% of the larger dose and between 3.3 and 13.4% of the smaller dose. Serum creatinine concentrations were serially measured in 10 hospitalized horses intramuscularly given 1.7 to 4.4 mg of gentamicin/kg 4 times a day' significant increase in creatinine concentration was not found.

Animals↗
PubMed1976

Placental transfer of clindamycin and gentamicin in term pregnancy.

The pharmacokinetics of clindamycin and gentamicin were studied in women given these antibiotics prior to cesarean section. Maternal clindamycin levels were within the normal range and cord levels were within the therapeutic range for this antibiotic. For gentamicin, however, maternal levels were depressed, with a concurrent depression of cord levels. This may have significant implications for the use of gentamicin in maternal and fetomaternal infections.

Bacterial Infections↗