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B Barron

Publications and source records attributed to B Barron.

11 recordsLinked to original sources
PubMed1995

Prominent small bowel Ga-67 uptake associated with Yersinial and tuberculous enterocolitis.

The nuclear medicine evaluation of the immunocompromised patient with fever of unknown origin may include the use of either labeled leukocytes or Ga-67 citrate, or both, in the search for an infectious focus. In recent years, labeled leukocytes (In-111 or Tc-99m) seem to have been employed preferentially by some. This is especially the case when the abdomen is a suspected site of involvement because of the normal colonic excretion of gallium that may complicate the interpretation of this study. The authors present the case of an immunocompromised patient with the interesting scintigraphic pattern of diffuse large and small bowel uptake of gallium secondary to biopsy proven Yersinia and tuberculous enterocolitis. A review of the recent literature reveals only one other similar case in which Yersinial disease was detected by Ga-67 scintigraphy. The present case illustrates that gallium's avidity for the atypical, less pyogenic, opportunistic infections common in immunocompromised patients justifies its continued use in such settings and, specifically, whenever tuberculosis is suspected.

Adult↗
PubMed1991

Corneal topography as a predictor of refractive change in the prospective evaluation of radial keratotomy (PERK) study.

The first operated eyes of 435 patients undergoing radial keratotomy in the Prospective Evaluation of Radial Keratotomy (PERK) study were evaluated by photokeratography to document the preoperative and postoperative corneal shape. We determined by regression analysis and analysis of variance that the corneal shape preoperatively improved the prediction of the corneal shape 6 months postoperatively in the 3-mm-clear-zone population. The reduction of myopia in all 435 eyes ranged from 1.25 to 9.75 diopters. We studied the effect of the preoperative corneal shape on this variability in the outcome of the surgery using rings 2 and 7 on photokeratography and corneal diameter. In the 3-mm-clear-zone group, eyes with flat prolate corneas had a greater reduction in myopia (4.65 D); those with steeper, more spherical corneas had less reduction in myopia (3.48 D). In addition, eyes with a 3-mm clear zone and flat central corneas alone (8.0 mm = 42.19 D) flattened approximately 0.75 D more than those with steep central corneas (7.0 mm = 48.21 D). In the 3.5-mm and 4.0-mm clear zone groups, the change in corneal curvature was not related to the preoperative curvature. A stepwise regression analysis of the 151 eyes in the 3.0-mm-clear-zone population demonstrated the following predictive equation for radial keratotomy; change in cycloplegic refraction = -14.55 + [-2.097 x average ring-2 radius] + [3.605 x average ring-7 radius] + [0.69 x horizontal corneal diameter] + [0.079 x age] + [-0.379 x spherical equivalent cycloplegic refraction]. There was a 1.17-D observed difference in the effect of radial keratotomy between those eyes with a steep/steep corneal topography (7.2% of the 3.0-mm-clear-zone population) and the flat/flat topography (29% of the 3.0-mm-clear-zone PERK population). A knowledge of corneal topography provides an additional tool for understanding the operative variability of radial keratotomy.

Cornea↗
PubMed1989

Endometrial polyps in postmenopausal patients receiving tamoxifen.

The histologic features of an endometrial polyp include irregular, often dilated glands, thick-walled blood vessels, and a fibrotic stroma. Such polyps may be responsive to some chemotherapeutic drugs that can exert hormonal effects. We report on endometrial polyps detected in three postmenopausal patients who were receiving tamoxifen for treatment of metastatic breast carcinoma. The clinical presentation in all cases was vaginal bleeding and all had documented uterine enlargement suggestive of an intrauterine malignancy. The polyps were large, measuring up to 9 cm in largest diameter. On histologic examination each polyp had extensive cystic glandular hyperplasia. In one case foci of atypical epithelial proliferation and predecidualization were noted. The atypical proliferation suggested a borderline neoplastic process and was strongly positive for carcinoembryonic antigen. These findings underscore the marked proliferative changes that can be induced in endometrial polyps in postmenopausal women receiving hormonally active chemotherapeutic agents.

Aged↗
PubMed1986

Developmental changes in visual and auditory contributions to speech perception.

Previous research has demonstrated that listeners make use of both auditory and visual information in bimodal speech perception. Preschool children appear to evaluate and integrate the two sources of information in the same manner as adults, but the children are less influenced by the visual source. The current experiments test a possible explanation of this difference and extend the question to younger children. It is possible that children are poorer lip-readers than adults and thus have less complete information about the visual source. Children and adults were tested with both auditory and visual sources and were also required to identify speech events on the basis of only the visual source. In addition to replicating the previous findings in the bimodal situation, the current experiments found that children are poorer lip-readers than adults. Furthermore, a positive correlation was observed between lip-reading ability and the size of the visual contribution to bimodal speech perception. A fuzzy logical model of speech perception provided a good quantitative description of the results even with the assumption that the visual information was equivalent in both the bimodal and lip-reading conditions. The results also contradict the categorical perception of speech events and any nonindependence in the evaluation of auditory and visual information in speech perception.

Adolescent↗
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↗
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↗