Search PubMed⌕ Search

Biomedical subjects

K Hillman

Publications and source records attributed to K Hillman.

60 records · Page 4Linked to original sources
PubMed1977

Characterization of IgC receptors of the fetal rabbit yolk sac membrane: localization to subcellular fraction and effects of chemical agents and enzymes on binding.

Previous studies have established the existence of IgG receptors on the endodermal cells of the fetal rabbit yolk sac membrane (YSM). The present study partially characterizes these cell-associated receptors. The specific binding of rabbit IgG (IgGR) to freshly prepared cell homogenates, nuclei-free brush border preparations, and plasma membrane-rich fractions confirms that receptor function is associated with the endodermal cell, and indicates that this function is localized on its apical brush border, specifically on its plasma membrane. The protein nature of the receptor is demonstrated by the loss of specific binding capacity after treatment of formalin-fixed YSM with papain and trypsin. Evidence has also been adduced which indicates that membrane carbohydrate is not involved in receptor function. Thus, treatment of YSM with neuraminidase, beta-galactosidase, mixed glycosidases, as well as oxidation of YSM with periodate all are without effect on its capacity to bind IgGR. The interaction of IgGR with the receptor elements of formalin-fixed YSM is partially ionic in character. NaCl reversibly inhibits binding of IbGR by 60%. Divalent ions such as Ca++ are not involved in this receptor-ligand interaction since EDTA-treated YSM binds IgGR to the same extent as do controls. Receptor material on fixed YSM resists extraction by non-ionic detergents, deoxycholate, and chaotropic agents.

Animals↗
PubMed1975

Preparation of IgG-binding membrane vesicles from the microvillar brush border of fetal rabbit yolk sac.

A one step procedure is described for the production of membrane vesicles from the endodermal microvillar brush border of the fetal rabbit yolk sac splanchnopleur. The vesicles, examined by light and electron microscopy, were shown to consist of biomolecular leaflet unit membrane, coated to varying extents with glycocalyx. By fluorescence microscopy, the homologous immunoglobulin, FITC-IgGR, has been shown to bind to the glycocalyx-coated vesicles as well as the glycocalyx-coated brush border of the intact yolk sac, whereas, the heterologous bovine immunoglobulin, FITC-IgGB, fails to bind under comparable conditions. These observations demonstrate the specificity of the receptors for the homologous IgG.

Animals↗
PubMedDate not supplied

Trauma outcomes: a death analysis study.

Survival and mortality outcomes for trauma patients admitted to Liverpool Hospital, Sydney were analysed to determine the adequacy of trauma care. TRISS and ASCOT survival probabilities and peer review were utilised to determine if deaths were avoidable. Evaluation methods were compared for assessment of care. During the study period 2205 trauma patients were admitted, 518 of which fulfilled the study entry criteria. There were 38 deaths. The age and Injury Severity Score (ISS) of survivors was 34 +/- 18 years, 9.8 +/- 9 (mean +/- sd) compared to age and ISS for nonsurvivors 37 +/- 22 years and 45 +/- 22*, *p < 0.001. Peer review suggested that 32 deaths were non avoidable, 4 potentially avoidable and 2 were probably avoidable. TRISS and ASCOT survival probabilities were > 0.5 in 16 and 18 patients respectively. TRISS and ASCOT had low positive predictive value (25%) in identifying avoidable deaths. The Z Score was 1.79. The standardised mortality ratio (SMR) was 1.16. The Effectiveness (E) value for outcome was 0.91. Poor communication within the Area Trauma System was the greatest contributor to avoidable deaths. All trauma deaths need peer review rather than solely relying upon ASCOT and TRISS probabilities to identify "unexpected" deaths for detailed review.

Adolescent↗
PubMedDate not supplied

Psychiatric morbidity following motor vehicle accidents: a review of methodological issues.

Motor vehicle accidents (MVAs), even those of a nonserious nature, appear to increase the risk of severe psychiatric morbidity in survivors. The present review examines the evidence indicating the levels of psychiatric morbidity in MVA survivors. Although no consistent profile has emerged, the most commonly reported symptoms are depression, anxiety, irritability, driving phobia, anger, sleep disturbances, and headache, with rates of posttraumatic stress disorder (PTSD) across studies of 0% to 100%. Variability in the type and severity of psychiatric outcomes may be due, in part, to methodological inadequacies in many studies, particularly the use of biased population samples, inclusion of subjects exposed to varied types of accidents, an absence of a clear definition of PTSD, a reliance on clinical judgment rather than the use of objective psychometric measures, the failure to include ratings of injury severity, and the absence of assessments for past exposure to traumatic events or preexisting posttraumatic reactions. The most important concern relates to the use of nonrepresentative samples, usually patients referred for medicolegal assessment in whom issues of compensation are of central importance. Gender and age differences distinguish the compensation group from the general population of MVA survivors, who therefore may also differ in the vulnerability to posttraumatic morbidity. It is argued that more systematic research on unselected subject samples is critical to establish epidemiological data on the true nature and extent of psychiatric morbidity following MVAs.

Accidents, Traffic↗
PubMedDate not supplied

Hydrogen production by rumen holotrich protozoa: effects of oxygen and implications for metabolic control by in situ conditions.

Experiments with washed suspensions of holotrich protozoa (Isotricha spp. and Dasytricha ruminantium) showed that both organisms have an efficient O2-scavenging capability (apparent Km values 2.3 and 0.3 microM, respectively). Reversible inhibition of H2 production increased almost linearly with increasing O2 up to 1.5 microM; higher levels of O2 gave irreversible inhibition. In situ determinations of H2, CH4, O2 and CO2 in ovine rumen liquor, using a membrane inlet mass spectrometer probe, indicated that O2 was present before feeding at 1-1.5 microM and decreased to undetectable levels (less than 0.25 microM) within 25 min after feeding. A transient increase in O2 concentration after feeding occurred only in defaunated animals and resulted in suppression of CH4 and CO2 production. The presence of washed holotrich protozoa decreases the O2 sensitivity of CH4 production by suspensions of a cultured methanogenic bacterium Methanosarcina barkeri. It is concluded that holotrich protozoa play a role in ruminal O2 utilization as well as in the production of fermentation end products (especially short-chain volatile fatty acids) utilized by the ruminant and H2 utilized by methanogenic bacteria. These hydrogenosome-containing protozoa thus both control patterns of fermentation by influencing O2 levels, and are themselves regulated by the low ambient O2 concentrations they experience in the rumen.

Animals↗