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Biomedical subjects

S Jordan

Publications and source records attributed to S Jordan.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Leptin in pituitary adenomas--a novel paracrine regulatory system.

A growing number of physiological and pathophysiological processes have been shown to be influenced by leptin apart from its first recognised role as a modulator of hypothalamic appetite and weight control centers. We investigated the presence and pattern of distribution of leptin mRNA and the mRNA of the long isoform of the leptin receptor in the normal pituitary and in different types of pituitary adenomas. We also studied leptin secretion from human pituitary tumors in culture, and the in vitro pituitary hormone release following stimulation with human leptin. Leptin mRNA expression was detected at a low level of expression in 50% of tumors but in none of the normal pituitaries. By immunohistochemistry, leptin was present in occasional scattered cells in the normal pituitary and in pituitary tumors. The leptin receptor long isoform was detected in the majority (65%) of pituitary tumors and in all normal pituitaries. It did not segregate with any particular tumor type, and varying levels of expression were detected between the tissues studied. 34% of pituitary adenomas showed leptin release into the incubation media during in vitro culture. Leptin mRNA, the mRNA of the long isoform of the receptor, or in vitro leptin release, did not correlate with tumor type or with any of the other pituitary hormones released. In vitro leptin stimulation of pituitary tumors caused stimulation of FSH and a-subunit secretion from a non-functioning adenoma and TSH secretion from a somatotroph adenoma. As the co-localisation of ACTH and leptin in corticotroph cells was previously suggested, we investigated whether in vivo ACTH release is accompanied by a simultaneous plasma leptin level rise (i) in peripheral plasma samples after food intake-induced ACTH rise in healthy obese and nonobese individuals and (ii) in petrosal sinus samples after CRH injection in Cushing's disease patients. Our data suggest that a rise in ACTH levels is not accompanied by detectable rise in leptin levels in peripheral and in petrosal sinus blood samples. In summary, leptin is synthesized and stored within the pituitary and may modulate other pituitary hormone secretion, although probably it does not contribute to plasma leptin level changes. Pituitary leptin may therefore be a novel paracrine regulator of pituitary function.

Adenoma↗
PubMedDate not supplied

Evaluation of two viral inactivation methods for the preparation of safer factor VIII and factor IX concentrates.

We report here the results of our evaluation of two procedures to eliminate viruses in factor VIII and factor IX coagulation factor concentrates. Both procedures were equally effective in the in vitro destruction of marker viruses. However, in a controlled infectivity test in chimpanzees, treatment at 60 degrees C for 20 hours inactivated greater than 500 and less than 10,000 chimpanzee infectious doses (CID) of hepatitis B virus, while treatment at 98 degrees C for 30 minutes inactivated less than 500 CID. Both methods were successful in preventing infection with an undetermined amount of an indeterminate non-A, non-B hepatitis agent. The 60 degrees C, 20-hour treatment method rendered 5.25 logs of the putative acquired immune deficiency syndrome virus, human T-cell lymphotrophic virus III/lymphadenopathy virus, added to factor VIII or factor IX concentrates, undetectable. Heat-treated factor VIII and factor IX complex concentrates prepared by these methods were tested against corresponding untreated control lots. There was no significant difference in the plasma recovery or plasma half-life of the factor (p greater than 0.05). The treated concentrates were equivalent to the control concentrates with respect to vital signs, clinical laboratory studies, and adverse reactions. The heat-treated concentrates appeared bioequivalent to the untreated concentrates with the additional benefit of inactivation of potentially present infectious viruses.

Animals↗
PubMedDate not supplied

Care of women having termination of first-trimester pregnancy.

The care of women having termination of pregnancy has always presented social, ethical and legal concerns to nurses and other healthcare professionals. Women having first-trimester termination of pregnancy may have the choice between medical and surgical methods. The process and procedure of these two approaches are discussed and the implications for nursing practice identified. There is now research evidence that explores women's experiences of these various methods and gives some insight into what the woman may experience. Nurses must have knowledge of these methods of termination to enable women to make the correct choices. The challenge for nurses then is to provide and evaluate information that is as effective as possible in meeting the needs of the individual woman.

Abortifacient Agents↗