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Biomedical subjects

B Ring

Publications and source records attributed to B Ring.

15 recordsLinked to original sources
PubMed1996

Effect of dirithromycin on human CYP3A in vitro and on pharmacokinetics and pharmacodynamics of terfenadine in vivo.

Terfenadine is metabolized by the cytochrome P-450 3A subfamily of enzymes (CYP3A). Certain macrolide antibiotic agents inhibit CYP3A and, when coadministered with terfenadine, result in a drug interaction. The authors compared the abilities of dirithromycin (a new macrolide antibiotic agent), its major metabolite erythromycylamine, and the known CYP3A substrate terfenadine to inhibit CYP3A in vitro. The hydroxylation of midazolam in human liver microsomes was used as a probe for CYP3A activity. Dirithromycin and erythromycylamine were low affinity inhibitors of CYP3A (inhibitory binding affinities of 493 mumol/L and 701 mumol/L, respectively); conversely, terfenadine was a moderate affinity inhibitor (inhibitory binding affinity of 28 mumol/L). Based on these data, the authors tested the hypothesis that dirithromycin would not interact with terfenadine in humans. Six healthy men received terfenadine alone (60 mg twice daily) for 8 days, after which dirithromycin (500 mg once daily) was added to the terfenadine regimen for an additional 10 days. The pharmacokinetics of terfenadine (and its acid metabolite) and the QTc interval were measured during both treatments, and it was found that neither parameter was affected. In this study, dirithromycin was found to have low affinity for human CYP3A in vitro, which is in accordance with the study's finding that in vivo dirithromycin has no major effect on the metabolism of the CYP3A substrate terfenadine in humans.

Adult↗
PubMed1994

Keratinocyte growth factor induces proliferation of hepatocytes and epithelial cells throughout the rat gastrointestinal tract.

Keratinocyte growth factor (KGF), a member of the fibroblast growth factor (FGF) family, was identified as a specific keratinocyte mitogen after isolation from a lung fibroblast line. Recently, recombinant (r)KGF was found to influence proliferation and differentiation patterns of multiple epithelial cell lineages within skin, lung, and the reproductive tract. In the present study, we designed experiments to identify additional target tissues, and focused on the rat gastrointestinal (GI) system, since a putative receptor, K-sam, was originally identified in a gastric carcinoma. Expression of KGF receptor and KGF mRNA was detected within the entire GI tract, suggesting the gut both synthesized and responded to KGF. Therefore, rKGF was administered to adult rats and was found to induce markedly increased proliferation of epithelial cells from the foregut to the colon, and of hepatocytes, one day after systemic treatment. Daily treatment resulted in the marked selective induction of mucin-producing cell lineages throughout the GI tract in a dose-dependent fashion. Other cell lineages were either unaffected (e.g., Paneth cells), or relatively decreased (e.g., parietal cells, enterocytes) in rKGF-treated rats. The direct effect of rKGF was confirmed by demonstrating markedly increased carcinoembryonic antigen production in a human colon carcinoma cell line, LIM1899. Serum levels of albumin were specifically and significantly elevated after daily treatment. These results demonstrate rKGF can induce epithelial cell activation throughout the GI tract and liver. Further, endogenous KGF may be a normal paracrine mediator of growth within the gut.

Animals↗
PubMed1993

Mesial temporal neurons in the macaque monkey with responses selective for aspects of social stimuli.

Primates possess a sophisticated cognitive ability to interpret and respond to the social actions of conspecifics. Neurons in the temporal lobes of macaque monkeys which are selective for the appearance and motions of conspecifics have been described previously; the results reported here indicate that pathways which integrate such information converge in mesial temporal regions. Single neuron data from an alert macaque viewing moving pictures of other monkeys engaged in a variety of behaviors are presented. Neurons in medial nuclei of the amygdala and adjacent mesial temporal cortex are sensitive to identity, movement, and high-level aspects of depicted scenes.

Amygdala↗
PubMed1991

Possible congenital hemolytic anemia in prehistoric coastal inhabitants of Israel.

The spread of thalassemia among prehistoric populations of the Mediterranean Basin has been linked to the increased risk to early agriculturalists posed by the Plasmodium falciparum parasite. The diagnosis of the disease in human skeletal remains, however, has usually been based on a single pathological criterion, porotic hyperostosis. This paper reports on what we believe to be the earliest case of thalassemia yet identified in the prehistoric record. Our diagnosis of the disease in an individual from the submerged Prepottery Neolithic B village of Atlit-Yam off the Israeli coast is based on a pathological humerus demonstrating a pattern of deformation characteristic of clinical thalassemia. The implications of these findings for our understanding of human societies undergoing the transition from foraging to agriculture in the Near East are discussed.

Anemia, Hemolytic, Congenital↗
PubMed1990

Response of neurons in the macaque amygdala to complex social stimuli.

The presence of neurons in macaque temporal cortex and amygdala which fire selectively in response to social stimuli has been demonstrated by several investigators. The extent to which such neuronal populations may respond to a broad range of social features, including expressive movements and interactions, has not been fully explored due to the difficulty of presenting such complex stimuli in a controlled fashion. We describe a method for presenting moving segments of macaque behavior, visual and auditory, to animal subjects during single unit recording. The method permits a broad range of stimuli to be used both as probes and as controls. In addition, a novel technique for monitoring eye position in alert macaque subjects is described. We present results from the medial amygdala and adjacent cortex, demonstrating that neurons in these regions respond selectively to features of the social environment.

Amygdala↗
PubMed1990

Efficiency of cranial bilateral measurements in separating human populations.

A set of 31 nonconventional paired cranial measurements, as well as six conventional nonpaired measures, were taken on 266 skulls, representing two related populations: Bedouins of the Israeli Negev Desert and Bedouins of the Sinai. The data were subjected to univariate and discriminant analyses to determine the relative efficacy of paired vs. conventional measures in sorting individuals according to tribal and sex affiliation. It was found that paired measures have greater discriminatory power (87%) than conventional ones (47%) in terms of classifying individuals belonging to human isolates derived from a common ancestor and sharing similar environmental conditions. This greater discrimination attests to the value of the level of "developmental noise" (a measure provided by fluctuating asymmetry) in sorting human populations. Possible explanations are proffered for the above finding.

Adult↗
PubMed1981

The anterior aspect of the knee joint.

The anterior structures of forty-eight knees were dissected analyzed quantitatively. Correlations were established among the twelve measured parameters of the distal quadriceps complex. Patellar height, width, and thickness tended to correlate with the dimensions of the soft-tissue structures and not with each other. To a high degree of predictability, the shape of the patella correlated with several parameters of the quadriceps complex. The width of the lateral patellofemoral ligament was the parameter most closely related to patellar shape.

Adult↗
PubMed1981

Patellar tracking.

Patellar tracking patterns were studied in 20 cadaver knees. The predominant pattern (Type 1) found in 17 knees included medial shift and medial tilt of the patella with respect to the tibial tubercle during extension of the knee. The remaining three knees (Type 2) showed a tendency toward lateral shift and tilt. Release of the lateral retinaculum had no effect on patellar tracking in most knees, while release of the medial retinaculum produced abnormal tracking in many Type 1 knees and all Type 2 knees. The "proximal realignment" (medial imbrication-lateral release) procedure increased the tendency of the patella to tilt and shift medially during extension.

Biomechanical Phenomena↗
PubMedDate not supplied

[Determination of secretory immunoglobulin A in the saliva of children with recurrent and chronic respiratory tract diseases during a stay at a health resort].

Investigations of sIgA-concentrations in saliva of 101 children in age of 2 to 4 years with recurrent and chronic airways diseases were performed by means of a sIgA specific enzyme linked immunoassay. The aim was to find out immunodeficiencies in comparison to healthy children (n = 50), and to test whether or not there is an influence of medical and climate treatment over a period of 8 weeks onto sIgA values in saliva. Only 3 children showed decreased sIgA concentrations. There were no differences between patients and healthy children because of the great interindividual variances of sIgA concentrations. An effect of climate cure to sIgA values could not be shown.

Bronchitis↗