Biomedical subjects

S Callahan

Publications and source records attributed to S Callahan.

16 recordsLinked to original sources

PubMed1995

Efficacy of frequent nebulized ipratropium bromide added to frequent high-dose albuterol therapy in severe childhood asthma.

OBJECTIVE: The objective of this trial was to determine the efficacy of frequent nebulized ipratropium added to high-dose albuterol therapy in children with severe asthma. METHODS: One hundred twenty children (5 to 17 years) of age) with severe acute asthma (forced expiratory volume in 1 second (FEV1), < 50% of the predicted value) were enrolled into a randomized double-blind three-arm placebo-controlled trial comparing three groups: group 1, three doses of nebulized ipratropium bromide within 60 minutes (250 micrograms/dose); group 2, one dose of ipratropium; group 3, no ipratropium. All patients were also treated with three doses of nebulized albuterol within 60 minutes (0.15 mg/kg per dose). Pulmonary function and clinical measures were assessed every 20 minutes for up to 120 minutes. RESULTS: The groups were comparable at baseline. At 120 minutes, the mean percentage of predicted FEV1 improved from 33.4% to 56.7% in group 1, from 34.2% to 52.3% in group 2, and from 35.4% to 48.4% in group 3 (p = 0.0001). The differences between groups were larger in those children with a baseline FEV1 < or = 30% of the predicted value: FEV1 increased from 24.5% to 50.9% in group 1, from 25.0% to 39.8% in group 2, and from 25.9% to 36.5% in group 3 (p = 0.0001). In group 1, 38% of the patients were hospitalized after the study, 44% in group 2, and 46% in group 3 (p value not significant). However, in patients with FEV1 < or = 30%, the hospitalization rates were 27% in group 1, 56% in group 2, and 83% in group 3 (p = 0.027). There were no toxic effects attributable to ipratropium. CONCLUSION: The addition of repeated doses of nebulized ipratropium to frequent high-dose albuterol therapy in patients with acute severe asthma is both safe and more effective than albuterol alone; its use in patients with very severe asthma may reduce hospitalizations.

Acute Disease↗

PubMed1993

Brain regional distribution of prion protein PrP27-30 in mice stereotaxically microinjected with different strains of scrapie.

Stereotaxic inoculation was used to examine the role of scrapie agent strain, inoculum, and injection site on the brain regional distribution of the prion protein, PrP27-30. Neither the type of inoculum nor the injection site influenced the distribution of PrP27-30 in brains of mice. Among the parameters examined, only the strain of agent affected the pattern of distribution and the yield of PrP27-30. Although mice injected into the cerebellum had the shortest incubation period, the cerebellum gave the lowest yield of the PrP27-30 among the seven brain regions examined. The positive correlation between PrP27-30 regional distribution and lesion profile (degree of vacuolation) reinforces the role of the PrPSC protein in scrapie pathogenesis.

Animals↗

PubMed1992

Quality of life.

Explore the source record for details and available documents.

Activities of Daily Living↗

PubMed1991

The viability of abstinence in an inner city adolescent population.

The purpose of our study was to investigate the different variables that lead teenagers to have sex, the psychological consequences they face as a result of having sex, and the viability of abstinence as an alternative. We used an anonymous self-administered questionnaire to address such issues as age of first intercourse and influence of family, peers, and physical consequences (ie, pregnancy, sexually transmitted diseases, and AIDS). Our research concluded that not only are teens having sexual intercourse at early ages, but that this early experience may be having detrimental consequences on their levels of self-esteem. We propose that the adolescent's search for identity is a strong motivational factor in engaging in sexual intercourse at an early age, and that delaying first coitus or choosing abstinence as a birth control method can be both empowering and ego-enhancing for the teenage client.

Adolescent↗

PubMed1990

Incubation periods and histopathological changes in mice injected stereotaxically in different brain areas with the 87V scrapie strain.

After stereotaxic injection into five different brain areas (cortex, caudate nucleus, substantia nigra, thalamus and cerebellum) of IM mice with the 87V scrapie strain, the cerebellum had the shortest incubation period. The vacuolation pattern was similar regardless of the area injected with extensive vacuolation in the thalamus, mesencephalon and hypothalamus. The pattern of amyloid plaques differed markedly depending on the area injected. In particular, no plaques were seen anywhere in the brain after injection into intact cerebellum, whereas injection into the four cerebral areas yielded plaques in the forebrain but not in the cerebellum. The incubation period after injection into bisected cerebella was much longer than after injection into intact cerebella. Mice injected on one side of bisected cerebellum had amyloid plaques in the forebrain but not in the cerebellum. There is a discussion of the finding that, although no plaques and virtually no vacuolation were seen in the cerebellum, the shortest incubation period occurred after injection into intact cerebellum.

Amyloid↗

PubMed1988

The examination of illicit cocaine.

A laboratory system of examination of illicit cocaine exhibits is described. Separation and identification of many of the components in exhibits are achieved by the use of capillary column gas chromatography and a Finnigan ion trap detector. Further examination and quantitation of the components of exhibits is achieved using two high performance liquid chromatographic (HPLC) systems. Both of these systems use identical reverse phase C8 columns. System 1 employs a solvent composed of 40% acetonitrile, 10% tetrahydrofuran and 50% 0.1% v/v aqueous triethylamine. The eluant is monitored at 280 nm. This system is preferred for routine quantitative analysis of cocaine and related alkaloids in exhibits. System 2 employs a solvent composed of 30% acetonitrile and 70% 0.05M phosphate buffer (pH = 5.0). The eluant from this system is monitored at both 220 and 280 nm. This system offers advantages in sensitivity. The relative retention times of a number of relevant substances as determined with gas chromatography and the two HPLC systems are given. The utility of the methodology for the identification and comparison of exhibits is demonstrated.

Chromatography, High Pressure Liquid↗

PubMed1987

Bayesian statistical theory in the preoperative diagnosis of pulmonary lesions.

We used a computerized Bayesian algorithm to assist in the preoperative diagnosis of pulmonary lesions. One hundred consecutive patients who were undergoing exploratory thoracotomy for newly discovered pulmonary lesions were prospectively evaluated. The Bayesian model used a total of 44 preoperative clinical and roentgenographic factors to categorize the lesions as benign or malignant. The Bayesian algorithm correctly categorized 96 of the 100 lesions, thereby providing an accuracy of 96 percent. The sensitivity of the model was 98 percent and the specificity was 87 percent. All but two of the 85 malignant lesions were correctly categorized and 13 of the 15 benign lesions were correctly analyzed by the model. These results indicate that computer-assisted diagnosis using the Theorem of Bayes may provide valuable preoperative information for the management of selected patients.

Adolescent↗

PubMed1985

Relation between testosterone concentration, sex role identity, and personality among females.

Eighty-four undergraduate female students completed Baucom's Masculinity and Femininity Scales, the Bem Sex Role Inventory, and the Adjective Check List. Testosterone concentration was determined from saliva samples provided by the women. The results indicated that sex role type was related to level of testosterone concentration. More specifically, undifferentiated females had much higher levels of testosterone concentration than did the feminine-sex-typed females. Also, females with high levels of masculinity (androgynous and masculine-sex-typed females combined) had somewhat higher testosterone levels than did feminine-sex-typed females. Adjectival correlates indicated that females with higher testosterone concentrations perceive themselves as self-directed, action-oriented, resourceful individuals; women with lower testosterone concentration view themselves as conventional, socialized individuals, possessing a caring attitude coupled with an anxious and dejected mood.

Adult↗

PubMed1981

Physical and chemical characterization of the major lactose-blockable lectin activity from fetal calf skeletal muscle.

The lactose-blockable lectin activity from fetal calf skeletal muscle has been purified to apparent homogeneity. The purification entails differential centrifugation, ammonium sulfate precipitation, asialofetuin affinity chromatography with a lactose gradient and ion-exchange chromatography on DEAE-cellulose. In the last step, the activity is resolved into a major and minor species, designated ion-exchange-purified lectins I and II, respectively. Both lectin activities are reversibly inhibited by lactose and appear as single bands with identical mobilities on SDS-polyacrylamide gel electrophoresis. Lectin II was not obtained in sufficient quantities for further characterization. Lectin I is characterized by a functional requirement for reducing agents and sensitivity to N-ethylmaleimide, which suggests a role for an essential thiol in its activity. Subunit molecular weight determinations by SDS-polyacrylamide gel electrophoresis (12 000 +/- 1 000) and by gel filtration in 6 M guanidine . HCl (13 000 +/- 1 000), when compared with that obtained under native conditions on Bio-Rad P-60 gels (27 000 +/- 2 000), suggest a true Mr of 25 000 +/- 3 000 for the dimeric molecule. Amino acid composition data, when fitted to this molecular weight, lead to the tentative conclusion that the intact dimer is composed of two very similar but compositionally non-identical chains, designated by alpha and beta. While the only detectable N-terminal amino acid is tryptophan, the isoelectric focusing pattern of lectin I supports this heterodimeric structure. In addition, a lactose-sensitive hemagglutinating activity which can be separated from the lactose-blockade activity by affinity chromatography was also observed.

Amino Acids↗

PubMed1979