PubMed Health⌕ Search

Biomedical subjects

K S Birdi

Publications and source records attributed to K S Birdi.

13 recordsLinked to original sources
PubMed1996

Clinician beliefs underlying autopsy requests.

The aim of the study was to use psychological theory to identify and evaluate factors influencing clinical autopsy requests. A series of pilot interviews were conducted with 20 clinicians to identify beliefs about the benefits and drawbacks, social groups and circumstances influential in the decision to make an autopsy request. The most common beliefs, together with measures of intention to request autopsies, were incorporated into a questionnaire which was distributed among all appropriate clinicians in four hospitals. Statistical analyses identified which beliefs had the most influence on clinicians' intentions to request autopsies. A total of 145 clinicians returned the questionnaire, a response rate of 42%. Clinicians were significantly more likely to request autopsy the more they thought that the outcome of requesting would be of educational value, would confirm clinical diagnoses, would not distress relatives, would not be time-consuming and that the request itself would receive support from their consultant. An autopsy request was unlikely in circumstances where clinicians felt uncomfortable when requesting relatives' permission and when the patients were elderly. The fear of causing distress to relatives and the degree of support from the clinician's consultant were found to be the strongest predictors of intention to request autopsies. These are two areas in which intervention could help to increase autopsy request rates.

Attitude of Health Personnel↗
PubMed1995

How do clinicians learn to request permission for autopsies?

A postal survey of 434 clinicians at four local hospitals was undertaken in order to identify the methods by which clinicians learn how to request permission for hospital autopsies and to assess the preferred techniques and timing of relevant communication skills training. The majority of 128 responding clinicians had learnt through personal experience with some assistance from senior colleagues and peers. Few clinicians appeared to have learnt through formal training. The preferred methods for the provision of communication skills training were training in small groups (such as seminars or tutorials) and observation of clinicians at work. The most desirable time for the provision of this training was considered to be between the beginning of the final undergraduate year and the end of the pre-registration house officer year. The communication skills training provided within medical education is in need of improvement. More emphasis should be given to clinical-task- or situation-specific applications such as requesting permission for autopsies.

Autopsy↗
PubMed1984

Melittin and the 8-26 fragment. Differences in ionophoric properties as measured by monolayer method.

Melittin is a major (approximately 50%) protein component of bee venom. This peptide is an amphiphilic protein, because, while the amino acid residues 1-20 are predominantly hydrophobic (with the exception of Lys-7), residues 21-26 are hydrophilic. The binding properties to vesicles and lipid bilayers of melittin have provided much useful information regarding biological (hemolytic) activity (Habermann, E., 1972, Science [Wash. DC], 177:314-322). Recent studies have convincingly established that the melittin monolayer (at air-water interface) model membrane system allows one to analyze the various forces present in such structures. We present comparative monolayer studies of melittin and the peptide fragment 8-26 regarding the channel formation for the selective anion (Cl-) penetration in monolayers, analogous to melittin (tetramer) channel function in lipid bilayer. The differences in surface pressure and surface potential of monolayers between native melittin and the 8-26 fragment suggest that these may be ascribed to Lys-7.

Bee Venoms↗
PubMed1983

The effect of fetal pulmonary surfactant production on the apparent microviscosity of amniotic fluid measured by fluorescence polarization.

The fluorescence properties of 1,6 diphenyl 1,3,5-hexatriene (DPH) in human amniotic fluid from the 10--20th week and from the 36--40th week of gestation are investigated. The probe environment of two stages of fetal development are studied by measuring the effect of temperature on the fluorescence polarization of DPH. The temperature profiles of fluorescence polarization of DPH in amniotic fluid and in liposomes prepared from chloroform/methanol extracts of the fluid are compared to the temperature profiles of liposomes prepares from phospholipids of known composition. The DPH binding structures of human amniotic fluid are further characterized by fractionation of lipid bodies by centrifugation on a Ficoll density gradient. The major part of fluorescence in third trimester amniotic fluid is emitted by DPH bound to pulmonary lamellar lipid bodies. The DPH environment in early gestational amniotic fluid is a distinctly different structure, which is more rigid than both sphingomyelin and dipalmityl lecithin at temperatures above 40 degrees C, and which is not chloroform/methanol extractable.

Amniotic Fluid↗
PubMed1978

The effects of diverse proteins on the solubilization of various hydrophobic probes by protein.detergent complexes.

The solubilization behavior of various protein.detergent complexes with respect to a particular water-insoluble organic substance ("hydrophobic probe") dimethylaminoazobenzene, was reported in earlier studies. The present report describes further the solubilization of other hydrophobic probes (e.g. Sudan II, naphthalene, anthracene and azobenzene) in various protein.sodium dodecyl sulfate complexes, in order to enlarge the scope of our understanding of these phenomena, which undoubtedly play a part in the transport of different water-insoluble organic substances in the living organisms. Solubilization by the various protein.SDS complexes is found to be specific for each probe. The amount of a particular probe solubilized is nearly always equal to the amounts which are solubilized by pure SDS micelles equivalent in amount to the SDS bound. Serious exceptions are found with two heme proteins (e.g. myoglobin and hemoglobin) and a few others. The hemeprotein.SDS complexes also exhibit regions of flat plateaus in the solubilization curves, whereas the binding equilibria show progressively larger amounts of SDS bound. The solubilization of probes by cationic detergent (cetylpyridinium chloride and cetyltrimethylammonium bromde).protein complexes indicate that the solubilization phenomena are related to the environment of the binding sites (the cationic detergents are known to bind at different sites on the protein than the anionic detergents, i.e. SDS in the present case). With anionic detergents the effective chain length of the pseudo-micellar protein.detergent clusters is sufficient to cause an increase in solubilizing effectiveness of about 1.5 between the complexes and pure micelles. When small probes such as naphthalene are used such ratios are found. With larger probes the effectiveness ratio is reduced to 1.0 or even less as a result of steric interference with the formation of the protein.detergent.probe clusters. The solubilization energy exhibited by each protein.detergent complex is largely determined by the individual protein, and by the charge on the detergent.

Colloids↗
PubMed1977

Differences in the solubilizing effectiveness of the sodium dodecyl sulfate complexes of various proteins.

The detailed reversible binding isotherms of sodium dodecyl sulfate (NaDodSO4) with 13 different initially native proteins are reported; the data were obtained at 20 degrees C and pH 7.1, ionic strength 0.033, with amounts bound with some proteins up to 1.1 g per g of protein. Although the isotherms of some of the proteins do not vary widely, extreme variations between certain classes are found. Thus, for example, hemoglobin and myoglobin both have high affinities and high binding capacities, while gamma-globulin, apoferritin, and transferrin have low initial affinities, and change drastically at higher concentrations. The protein-NaDodSO4 complexes solubilize the water-insoluble dye dimethylaminoazobenzene (DMAB) as effectively as micelles of pure NaDodSO4 when only small amounts (0.2 to 0.5 g/g of NaDodSO4) are bound. In most cases this effectiveness falls progressively as larger amounts are bound, and may even cease altogether at limits characteristic of the individual protein. With some of the latter, a second region of renewed solubilization occurs when substantially higher amounts of NaDodSO4 are present. In all cases, solubilization by ordinary micelles in normal amount occurs when the free NaDodSO4 concentration exceeds the critical micelle concentration, but the binding of NPADodSO4 to the protein also increases, in competition with formation of micelles. With some, but not all proteins the NaDodSO4 bound at concentrations above the cmc also solubilizes DMAB. In such cases the solubilizations by the protein-NaDodSO4 complexes and by the simple micelles are additive. The significance of the differences in binding and solubilizing encountered among these proteins is discussed in terms of surface structure, cooperativity of binding, and protein composition. No certain correlations with content of most amino acids, subunit structure, solubility, and hydrophobicity have been found, but there is a weak inverse dependence of solubilizing effectiveness on molecular size and indications of a strong dependence on content of cationic groups.

Kinetics↗
PubMed1973

The binding of cationic detergent to insulin, zinc-insulin and iso-insulin.

Insulin, zinc-insulin and iso-insulin were precipitated by cetyltrimethylammonium bromide when the detergent/protein molar ratio was less than 10:1, whereas no precipitation was observed at ratios greater than 10:1. It is concluded that the detergent binds as a dimer at each binding site at ratios greater than 10:1. U.v. difference spectra indicated that the tyrosine residues were perturbed by detergent binding.

Chemical Precipitation↗