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Biomedical subjects

K Williams

Publications and source records attributed to K Williams.

At least 217 records · Page 12Linked to original sources
PubMed1997

Cellular localization of the chemokine receptor CCR5. Correlation to cellular targets of HIV-1 infection.

The chemokine receptor CCR5 has recently been described as a co-receptor for macrophage-tropic strains of human immunodeficiency virus (HIV)-1. In this study, using a panel of monoclonal antibodies specific for human CCR5, we show by immunohistochemistry and flow cytometry that CCR5 is expressed by bone-marrow-derived cells known to be targets for HIV-1 infection, including a subpopulation of lymphocytes and monocyte/macrophages in blood, primary and secondary lymphoid organs, and noninflamed tissues. In the central nervous system, CCR5 is expressed on neurons, astrocytes, and microglia. In other tissues, CCR5 is expressed on epithelium, endothelium, vascular smooth muscle, and fibroblasts. Chronically inflamed tissues contain an increased number of CCR5+ mononuclear cells, and the number of immunoreactive cells is directly associated with a histopathological correlate of inflammatory severity. Collectively, these results suggest that CCR5+ cells are recruited to inflammatory sites and, as such, may facilitate transmission of macrophage-tropic strains of HIV-1.

Animals↗
PubMed1997

An evidence-based approach to clinical practice guidelines in periodontics.

The use of clinical practice guidelines has received considerable attention in medicine and dentistry for improving clinical decision making and cost-effective care. Leaders in dentistry are increasingly calling for improved standardization of treatment through the development of clinical practice guidelines based on empiric clinical evidence. Guidelines have been shown to minimize treatment variability and ensure the quality and cost-effectiveness of care. Other potential applications include educating individuals or groups; development of quality indicators; improved allocation of resources such as insurance payment decisions; and reduced risk of liability for negligent care. Recently, a series of evidence-based clinical algorithms and practice guidelines were developed for regenerative periodontal treatment. Such guidelines have the potential to improve outcomes of periodontal care for providers, patients, and other interested parties. This review discusses the rationale for guideline development and the role of clinical practice guidelines in the area of periodontal decision making and provision of care.

Decision Making↗
PubMed1996

Change for the better?

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Attitude of Health Personnel↗
PubMed1996

Separating dual effects of zinc at recombinant N-methyl-D-aspartate receptors.

The effects of Zn2+ on recombinant N-methyl-D-aspartate (NMDA) receptors expressed in Xenopus oocytes were examined. Zn2+ inhibited macroscopic currents induced by NMDA at both NR1/NR2B and NR1/NR2A receptors. At NR1/NR2B receptors the Zn2+ concentration-inhibition curve was monophasic, with an apparent affinity for Zn2/ of 1.6 microM, and inhibition by Zn2+ was not voltage-dependent. In contrast, the Zn2+ concentration-inhibition curve at NR1/NR2A receptors was biphasic, with high (Ki = 0.08 microM) and low (Ki = 30 microM) affinity components. The high affinity component produced a maximal inhibition of 45% of macroscopic NMDA currents and was not voltage-dependent. Thus, Zn2+ is more potent in producing voltage-independent block at NR1/NR2A than at NR1/NR2B receptors, but the maximal effect of Zn2+ is smaller at NR1/NR2A than at NR1/NR2B receptors. The low affinity component of Zn2+ inhibition at NR1/NR2A receptors was voltage-dependent and may represent an open-channel blocking effect of Zn2+. Differential effects of Zn2+ at recombinant NMDA receptors containing different NR2 subunits provide a potential marker for distinguishing subtypes of native NMDA receptors and for dissecting the site and mechanism of action of Zn2+ at these receptors.

Animals↗
PubMed1996

Salt loading abolishes osmotically stimulated vasopressin release within the supraoptic nucleus.

Central and systemic osmotic stimulation increase vasopressin (VP) release within the supraoptic nucleus (SON) and into the general circulation. We examined whether changes in water/electrolyte balance affect the neurosecretory responses to these stimuli. Urethane-anesthetized control, salt-loaded (2% NaCl for 2 days) or water-deprived (for 2 days) male rats were implanted with an arterial catheter and bilateral microdialysis probes into the SON. Plasma and SON VP levels were measured before and after acute osmotic stimuli were administered intraperitoneally (i.p.) and then directly into the SON. Water deprivation resulted in elevated basal intranuclear and plasma VP levels. Intraperitoneal hypertonic saline (HS) and direct osmotic stimulation of the SON increased VP release into the SON in both the control and water-deprived groups. Salt loading abolished the intranuclear VP response to both stimuli. Osmotically induced release of VP into plasma was not different between the three groups. These data demonstrate that salt loading, but not water deprivation, alters the central neurosecretory VP response to acute osmotic stimulation.

Animals↗
PubMed1996

Association of common health symptoms with bullying in primary school children.

OBJECTIVE: To estimate the prevalence of bullying in primary school children and to examine its association with common symptoms in childhood. DESIGN: Semistructured health interview conducted by school nurses as part of a school medical. SETTING: Newham, east London. SUBJECTS: All children in year 4 of school during the academic year 1992-93. MAIN OUTCOME MEASURES: Reported bullying and common health symptoms. RESULTS: 2962 children (93.1% of those on the school roll) were interviewed (ages 7.6 to 10.0 years). Information about bullying was not recorded for 114 children, 22.4% (95% confidence interval 20.9 to 24.0) of children for whom information was available reported that they had been bullied. There was an association between children reporting being bullied sometimes or more often and reporting not sleeping well (odds ratio 3.6, 2.5 to 5.2), bed wetting (1.7, 1.3 to 2.4), feeling sad (3.6, 1.9 to 6.8), and experiencing more than occasional headaches (2.4, 1.8 to 3.4) and tummy aches (2.4, 1.8 to 3.3). A significant trend for increasing risk of symptoms with increased frequency of bullying was shown for all reported health symptoms (P < 0.001). CONCLUSIONS: Health professionals seeing primary schoolchildren who present with headaches, tummy ache, feeling sad or very sad, bed wetting, and sleeping difficulties should consider bullying as a possible contributory factor.

Aggression↗