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Biomedical subjects

B Barron

Publications and source records attributed to B Barron.

26 records · Page 2Linked to original sources
PubMed1983

Atypical immature metaplasia (AIM). A subset of human papilloma virus infection of the cervix.

Atypical immature squamous metaplasia (AIM) is a poorly understood lesion with uncertain biological and clinical significance. This report reviews 170 cases of cervical condylomata and 60 cases of high-grade cervical intraepithelial neoplasia (CIN II/III); AIM was found in association with 34% of condylomata and 16% of high-grade CIN. Thirty-seven cases of AIM alone were reviewed and nearly all presented with a cytologic diagnosis of CIN I or condyloma and a colposcopic appearance of white epithelium with or without punctation and mosaic structure. The mean ages of patients with condylomata, AIM, CIN II, and CIN III were 27, 27, 32, and 37 years, respectively. By immunoperoxidase techniques 75% of condylomata, 16% of AIM, and 0% of CIN lesions were positive. The histologic criteria for the diagnosis of AIM and it's morphologic distinction from CIN and relationship to condylomata, are outlined. AIM is a distinct histologic entity that shares similar epidemiologic, morphologic and biologic characteristics with condyloma. When AIM is found alone in biopsy material, careful correlation of cytology, and biopsy results should be performed and therapy should be based on the size and distribution of the lesion.

Adult↗
PubMed1983

Human papilloma virus infection (condyloma) of the cervix and cervical intraepithelial neoplasia: a histopathologic and statistical analysis.

Two hundred fifty consecutive cases previously diagnosed as advanced intraepithelial neoplasia (CIN 2 and CIN III) were reviewed and examined for the presence of coexisting condyloma. When the mean ages and age distributions were analyzed, there was a consistent shift of the age distribution to a younger age among women with CIN and condyloma as opposed to CIN alone. Furthermore, when the relationship between age and case accumulation was normalized from a curvilinear to a linear relationship, there were significant differences in the slope of the accumulation rate between cohorts of CIN III with and without condyloma. These differences suggest that the concordant observation of both lesions in a given patient is not a random process resulting from two independent events but rather indicates an underlying dependence between the two (i.e., condyloma and CIN). It cannot, however, be determined statistically whether the associated condyloma is directly responsible for the CIN lesion or hastens its transit time.

Adult↗
PubMed1981

Effects of divalent metals on the specificity of inhibitors of the cyclic nucleotide phosphodiesterases from bovine heart.

Divalent metals used to support phosphodiesterase (EC 3.1.4.-) activity have been found to influence the substrate and enzyme specificity of many phosphodiesterase inhibitors in studies of the hydrolysis of cyclic AMP and cyclic GMP by the calmodulin-dependent and cyclic AMP-specific phosphodiesterases from bovine heart. Many compounds displayed marked differences in substrate specificity and inhibitory potency in the presence of Mg2+, as compared with Mn2+, when studied with the unactivated form of calmodulin-dependent phosphodiesterase, while few compounds displayed differences in the presence of calmodulin. With a single divalent metal, marked differences in inhibitory potency and substrate specificity were also observed in the absence or presence of calmodulin suggesting that alterations in calmodulin and/or Ca2+ levels may greatly affect the response to phosphodiesterase inhibitors. Divalent metals did not alter the effects of inhibitors on the hydrolysis of cyclic AMP by the cyclic AMP-specific phosphodiesterase, however divalent metals would probably indirectly influence the relative cellular level of cyclic AMP hydrolyzed by this enzyme, and therefore the effects of inhibitors, through metal effects on the calmodulin-dependent phosphodiesterase. No correlation was found between the inhibitory activity of the compounds, many of which were cyclic nucleotide analogs, and their ability to activate cyclic AMP-dependent or cyclic GMP-dependent protein kinases or to affect cyclic AMP-dependent protein kinase activity by displacing bound cyclic AMP.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1972

Performance in multiple fixed-interval schedules.

The performances of five pigeons were studied under a variety of multiple fixed-interval schedules in which both component duration and reinforcement rate were varied. The three series of experimental conditions were: (a) when the ratio of component durations equalled the reciprocal of the ratio of component reinforcement rates; (b) when the component durations were equal; and (c) when the ratio of component durations equalled the ratio of component reinforcement rates. Relative response rates were related to relative reinforcement rates in the same manner as in multiple variable-interval schedules, but no effect of component duration was found.

Journal Article↗
PubMed1968

Studies on streptococcal bacteriophages. I. Burst size and intracellular growth of group A and group C streptococcal bacteriophages.

Evidence has been presented that the burst size in the Group A and Group C streptococcal phage-host systems are in general similar producing approximately 13 phage particles per infected coccus. The exception was the C1 phage which produced 10 times more virus particles than all the other phages tested. The eclipse period for the A25 phage-host system was found to extend for 34 min, while the C1 phage were found as early as 10 min after infection. Conclusive evidence has been presented indicating that mercuric ions at 2.5 x 10(-6)M concentration have the ability to halt intracellular phage production at any point during the infective cycle of A25 bacteriophages. This blocking action can then be quickly reversed with the addition of reduced glutathione with subsequent completion of the viral cycle.

Bacteriophages↗