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Biomedical subjects

A Smith

Publications and source records attributed to A Smith.

At least 1,369 records · Page 76Linked to original sources
PubMed1976

Micellar solubilization of fatty acids in aqueous media containing bile salts and phospholipids.

1. The solubility of fatty acids in aqueous media containing bile salts alone and in admixture with either lecithin (phosphatidylcholine) or phosphatidylethanolamine was determined. 2. Over the pH range 2-0-7-4, the order of fatty acid solubility in aqueous solutions containing bile salts was linoleic greater than oleic greater than elaidic greater than palmitic greater than stearic. The solubility of each fatty acid increased as the pH of the miceus solutions of bile salts greatly increased the solubility of palmitic acid and stearic acid. 4. In the presence of bile salts and lecithin, the solubility of oleic acid and elaidic acid decreased with increasing pH of the micellar solution, indicating a competitive effect between the fatty acid anions and lecithin. The solubility of linoleic acid increased linearly with lecithin concentration. 5. Phosphatidylethanolamine as an additive to bile salts increased the solubility of both saturated and unsaturated fatty acids in the pH range 2-3-7-4. The effectiveness of phosphatidylethanolamine as an amphiphile was similar to that of lecithin, although at pH 3.0 fatty acid solubility was greater in the presence of phosphatidylethanolamine. 6. The significance of these findings is discussed in relation to the intestinal absorption of fatty acids in sheep.

Animals↗
PubMed1976

Influence of the products of phospholipolysis of phosphatidylcholine on micellar solubilization of fatty acids in the presence of bile salts.

1. The solubility of fatty acids in aqueous solutions containing bile salts and lysolecithin at pH values between 2-0 and 7-4 was studied. Both the 1-acyl and 2-acyl isomers of lysolecithin increased the solubility of fatty acids to the same extent, the order of solubility being linoleic greater than oleic greater than elaidic greater than palmitic greater than stearic. 2. The influence of the products of phospholipolysis of lecithin on palmitic acid solubility was determined. On a molar basis, lysolecithin was more effective than were bile salts in promoting the solubilization of the fatty acid. 3. In bile salt solutions in which the phospholipid concentration was constant on a molar basis, in solubility of palmitic acid decreased linearly with the progressive replacement of lecithin by lysolecithin. Palmitic acid was solubilized to the same extent on replacing lecithin with lysolecithin on a constant weight basis. 4. In bile salt solution containing lysolecithin and oleic acid in equimolar amounts, the solubility of palmitic acid was similar to that in bile salt solution containing lecithin in equivalent proportion. 5. The results are discussed in relation to the action of phospholipolytic activity on the intestinal absorption of fatty acids in sheep.

Animals↗
PubMed1976

Predicting the impact of severe illness in families.

The goals of this survey of families with a leukemic child were (1) to develop simple, objective methods of describing the overwhelming impact of this serious illness on families, and (2) to test the value of family coping responses that manifested themselves immediately after the diagnosis in predicting stress outcome as measured a few months after the death of the child. The findings indicate that most of the families with a seriously ill child were still overwhelmed by this crisis three months postmortem. The effectiveness of these families appeared, at that time, to have been substantially reduced in that their members suffered from multiple problems affecting their health and normal functioning. The evidence indicates substantial differences in the impact of the illness on the survey families, in accord with the effectiveness of their initial coping response to the diagnosis. Adaptive coping families were far superior in outcome than were maladaptive coping families in the follow-up survey. The study findings support the view that the optimal period for intervention is during the early, acute stage of the crisis, immediately following the confirmation of the diagnosis, when the family is making those decisions associated with maladaptive coping and poor stress outcome.

Adaptation, Psychological↗
PubMed1976

Autoimmune reaction to a liver specific membrane antigen during acute viral hepatitis.

Lymphocyte cytotoxicity for isolated hepatocytes has been demonstrated in 93% of cases of acute viral hepatitis tested within two weeks of the onset of symptoms. The frequency of cytotoxicity during this time was similar for HBsAg positive and negative cases. However, after this time it was significantly higher in HBsAg positive than negative cases, 90% and 25% respectively (P less than 0-01). Cytotoxicity was found in B-cell, but not T-cell, enriched fractions of lymphocytes, compatible with an antibody-dependent K-cell mediated reaction. In two cases the assay remained positive on retesting six months later, and follow-up liver biopsies showed the features of chronic aggressive hepatitis. These findings suggest that, in addition to the known immunological reactions against viral antigens that occur during the acute phase of viral hepatitis, an autoimmune reaction directed against a liver specific protein is also initiated; and if this reaction persists then chronic hepatitis may develop.

Acute Disease↗
PubMed1976

The conducting tissues in primitive ventricular hearts without an outlet chamber.

We have studied the disposition of the cardiac conducting tissues in four hearts from situs solitus individuals possessing primitive ventricles without outlet chambers. These hearts correspond to the type of univentricular heart defined as common ventricle by Lev. All the hearts studied possessed normally positioned great arteries. Two groups, each consisting of two hearts, could be distinguished. The first type possessed a small posterior ridge which divided the posterior portion of the primitive ventricle into right and left ventricular sinuses. The papillary muscles to the atrioventricular valves were separate structures and arose on each side of this posterior ridge. The conducting tissues in these hearts arose from an atrioventricular node situated in the atrial septum but deviated posteriorly. The atrioventricular bundle pierced the fibrous annulus posteriorly and descended on the posterior ridge, lying to its left side. A bifurcation was not identified, and bundle branches were not present. The other two hearts had no posterior ridge. A common posterior papillary muscle supported both atrioventricular valves, and in one a marked anterior muscle bar produced obstruction of the pulmonary outflow tract. The connecting atrioventricular node was situated laterally in the right atrioventricular valve orifice, and the atrioventricular bundle descended into the right parietal wall of the primitive ventricle. A bifurcation and bundle branches were not observed. The disposition of conducting tissue in these hearts differs from that found in "primitive ventricle with outlet chamber" in that the connecting atrioventricular node and bundle are situated anteriorly and are intimately related to the transposed pulmonary artery outflow tract in the latter anomaly. The surgical significance of these findings is emphasized.

Child, Preschool↗
PubMed1976

Reliability of psychiatric assessment in older patients.

A number of the causes of psychiatric diagnostic disagreement are discussed in this paper. The use of the Geriatric Mental Status interview to achieve diagnostic reliability is examined in three studies in which U.S.--U.K. Cross-National Project psychiatrists rated and diagnosed thirty-two British and twenty-one American patients. There were no systematic differences between U.S. and U.K. team members in their diagnoses; and agreement on six principal diagnostic categories was achieved in about three-quarters of the cases. The reliability fo the ratings of psychopathology that formed the basis for the diagnoses was satisfactory and is reported in detail.

Aged↗
PubMed1976

Right juxtaposition of the auricular appendages.

3 cases are described exhibiting the rare malformation of right juxtaposition of the auricular appendages. 1 case was encountered unexpectedly during surgical repair of an atrial septal defect and the patient survived. In this instance the segmental arrangement was solitus-concordant-normally connected arteries and the only associated defects in the heart were the atrial septal defect and a persistent left superior vena cava. In contrast, the other cases were discovered at autopsy and in both the juxtaposition accompanied severe additional anomalies. Common atrioventricular canal deformities were present in ambiguus 1-loop hearts and the ventriculo-arterial connections were double outlet right ventricle with d-malposition and normal connections with d-malposition respectively. Histological study in one of the hearts confirmed the presence of 1-bulboventricular looping, and showed an unusual arrangement of conducting tissues. Two atrioventricular nodes were present, and each communicated via separate atrioventricular bundles with the ventricular conducting tissues. The cases are compared with other reported examples of right juxtaposition, and it is indicated that whereas right juxtaposition is frequently an isolated finding this is rarely the case in the more common left juxtaposition.

Child, Preschool↗
PubMed1976

Secretion and role of androgen-binding proteins in the testis and epididymis.

The Sertoli cell appears to be a target cell for both FSH and androgen. FSH stimulates the Sertoli cell to produce an androgen-binding protein (ABP) which may serve to increase the accumulation of androgen in the seminiferous tubular epithelium and make it available for binding by intracellular androgen receptors. This might be one way by which FSH enhances the action of androgen on spermatogenesis. Androgen acts on the Sertoli cell to increase its response to FSH resulting in increased production of ABP and of other substances which exert trophic effects on spermatogenesis.

Androgens↗