200-keV He+-ion irradiation effects on the properties of pulsed-laser-deposited YBa2Cu3O7-x thin films.
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Biomedical subjects
Publications and source records attributed to P England.
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To investigate the role of the sulfate group and the influence of cyclization on the biological properties of conformationally constrained CCK8 analogues, three series of compounds were synthesized: Boc-Glu-Tyr-Nle-D-Lys-Trp-Nle-Asp-Phe-NH2 (1), Boc-Glu-Tyr(SO3H)-Nle-D-Lys-Trp-Nle-Asp-Phe-NH2 (2), and Boc-Glu-Tyr-(SO3H)-Nle-D-Lys-Trp-Nle-Asp-Phe-NH2 (3) (series A); Boc-D-Glu-Tyr-Nle-D-Lys-Trp-Nle-Asp-Phe-NH2 (4), Boc-D-Glu-Tyr(SO3H)-Nle-D-Lys-Trp-Nle-Asp-Phe-NH2 (5), Boc-D-Glu-Tyr(SO3H)-Nle-D-Lys-Trp-Nle-Asp-Phe-NH2 (6), and Boc-D-Glu-Tyr(SO3H)-Nle-D-Nle-Trp-Asp-Phe-NH2 (7) (series B); and Boc-gamma-D-Glu-Tyr-Nle-D-Lys-Trp-Nle-Asp-Phe-NH2 (8), Boc-gamma-D-Glu-Tyr(SO3H)-Nle-D-Lys-Trp-Nle-Asp-Phe-NH2 (9), and Boc-gamma-D-Glu-Tyr-(SO3H)-Nle-D-Lys-Trp-Nle-Asp-Phe-NH2 (10) (series C). The selectivity of these peptides was studied by measuring their ability to displace [3H]propionyl-CCK8 from guinea pig brain and pancreatic membranes. All the peptides displayed low affinities (KI values around 10(-6) M) for the pancreatic receptors (A type). In contrast, both sulfated and nonsulfated cyclic analogues displayed high affinities for central-type binding sites (B type), especially compounds belonging to series C [KI(8) = 4.7 nM and KI(9) = 0.56 nM]. In all series the linear analogues had relatively poor affinities (KI approximately 300 nM) for B-type receptors. Compound 9 was the most potent (KI = 0.56 nM) and selective [KI(pancreas)/KI(brain) = 4464] for central-type CCK receptors of guinea pig. The cyclization of the N-terminal region of CCK8 permits one therefore to obtain probes for central receptors, and small changes directed toward the cyclic part modulate the affinity for these receptors.
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A highly efficient method is described for obtaining proliferative epithelial cells from adult rat livers for the reproducible establishment of liver epithelial cell strains. When cells were isolated from livers of 10- to 15-wk-old male Fischer 344 rats by a collagenase-perfusion method, collected by centrifugation at 50 X g for 5 min, and cultured in Williams' medium E containing fetal bovine serum and dexamethasone, colonies of epithelial cells different in size and morphology from hepatocytes were obtained. Sequential perfusion with collagenase and dispase yielded numerous epithelial cell colonies. When isolated cells were fractionated by differential centrifugation, the great majority of hepatocytes were sedimented at 50 X g for 1 min, whereas many non-hepatocytic cells remained in the supernatant and could be sedimented by a second centrifugation at 50 X g for 5 min. Culture of the two fractions revealed that almost all the epithelial cell colonies were derived from cells in the non-hepatocytic cell fraction. The epithelial cells were cytochemically negative for gamma-glutamyl transpeptidase activity, whereas an increase in the activity was detected in hepatocytes with duration in culture. Ultrastructural characteristics of hepatocytes were not found in the cells of newly established cell strains. These results suggest that adult rat liver epithelial cells propagable in culture were derived from a cell type other than the hepatocyte.
This paper describes key developments in the national validation of certificate courses, and the setting up of a network of co-operative curriculum development projects between the Health Education Council, local health education services and their officers, and colleges and their tutors. These developments are encompassed in a centre-periphery interactional model which, when projected into the future, displays continued active development. This model for the training and role development of health educators has considerable adaptability for use in other situations.
FSH levels were assayed in 300 men attending with infertile marriages. From this number, releasing factor tests were carried out in 24 men with oligozoospermia and an initial FSH below our normal mean. In all of these cases there was a response to releasing factor. Isolated FSH deficiency is likely to be rare in adult men presenting with infertility and no previous endocrinological history.
The effects of bromocriptine and quinestrol upon coagulation and fibrinolysis during the puerperium were studied. Quinestrol therapy was associated with increased levels of factors VII and IX and decreased antithrombin activity on the sixth postpartum day, and increased factor IX and plasminogen levels on the fourteenth postpartum day. Six weeks after delivery elevated levels of factors II and VII and of plasminogen were recorded in women given quinestrol. Bromocriptine therapy only caused an increase in the level of factor IX at six weeks after delivery. Compared to controls, patients given bromocriptine had lower prolactin and higher FSH levels during the puerperium whereas the patients given quinestrol had increased prolactin levels and a late fall in FSH levels.
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Prolactin, FSH and LH were measured in the plasma of 208 male partners of infertile marriages. We found 1 case of marked hyperprolactinaemia in 82 oligozoospermic men (1.2%). There was no difference in the mean prolactin levels of men with normal sperm counts and men with oligozoospermia or azoospermia. One-third of the men with azoospermia and with sperm density of less than 10 million had marked FSH elevation and our experience confirms the work of others that this indicates a poor prognosis.
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As a result of routine screening of ante-natal patients by urinary total oestrogens and plasma human placental lactogen (HPL) from 35 weeks, a rare placental sulphatase deficiency was indicated which was later confirmed by in vitro studies of placental enzyme activities.
Maternal plasma levels of human placental lactogen (HPL) are decreased in hypertensive pregnancies and the concentration is related to the severity of the condition. Of infants who had HPL concentrations in the fetal danger zone (more than 2 SD's below normal mean) 75 per cent developed fetal distress, neonatal asphyxia or were light for dates. Patients who are identified in this way have lighter infants and placentae than their unidentified counterparts with normal HPL levels.
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