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Biomedical subjects

J F Nelson

Publications and source records attributed to J F Nelson.

At least 91 records · Page 5Linked to original sources
PubMed1982

Local action of parathyroid hormone (1-34) and (1-84) at the parotid gland of sheep.

Administration of bovine parathyroid hormone (PTH) preparations increased the phosphate concentration in the parotid saliva of sheep. Data on the site of action of PTH (1-84) were obtained by (a) equimolar infusions of PTH (1-84) and (1-34) directly into the arterial blood supply of the vascularly isolated parotid gland in anaesthetized sheep, (b) intravenous infusion of PTH (1-84) at a similar rate and (c) intra-arterial infusion of PTH (1-84) with complete drainage of the venous effluent from the gland during the infusion. Results showed substantial time- and dose-response identity of the two peptides, at 10(-9) to 4 X 10(-9) mol/l in arterial blood, in raising salivary phosphate concentration. The effect of PTH (1-84) was not due to recirculated fragments because the response was obtained when recirculation was prevented by complete venous drainage and little or no response occurred when the same infusion was given i.v.

Animals↗
PubMed1981

Pituitary tumorigenesis in aging female C57BL/6J mice: a light and electron microscopic study.

Spontaneous pituitary tumors have been studied by light and electron microscopy in female C57BL/6J mice at 2 1/2, 11, 15, 22, 23, 24 and 30 months. Tumors were evident macroscopically in greater than 50% of mice 22 months or older, and greater than 80% on microscopic evaluation. Active and hypertrophied mammotrophs were the predominant cell type within the tumors at 22-30 months, often totally filling large portions of the tumor mass. Exocytosis of secretory granules was extensive from the mammotrophs, but much less abundant from other parenchymal cells. Somatotrophs and gonadotrophs were also present, and appeared active and often strikingly hypertrophied. The tumors were characterized by disruptions of parenchymal and capillary integrity which resulted in the formation of large vascular lakes lined solely by tumor cells, generally mammotrophs. Apparent metastasis of tumor cells into the vascular lakes was also observed. In 11- and 15-month mice small tumors or pretumor foci were evident in some mice on microscopic evaluation, although they were not visible macroscopically. Their degree of development was somewhat variable, but they had essentially the same features as more advanced tumors in older mice. pretumor foci were characterized by more moderate disruptions of parenchymal cell and capillary integrity; cellular hypertrophy, particularly of somatotrophs and gonadotrophs; and the presence of small vascular lakes. In 2 1/2-month mice tumors could not be localized macroscopically or microscopically, and the pituitary was composed of well-defined cell cords and an intact capillary bed. However, small focal zones of capillary and tissue disruption were apparent occasionally in 2 1/2-month mice. These findings indicate that the process of pituitary tumorigenesis in female C57BL/6J mice is initiated by midlife, with subsequent progressive development into large, mammotroph-dominated tumors.

Aging↗
PubMed1980

The effect of carbonic anhydrase inhibitors on the anionic composition of sheep's parotid saliva. With an appendix on uncatalysed carbon dioxide-water kinetics by P. T. McTigue.

1. The effects of the carbonic anhydrase inhibitors, acetazolamide, ethoxzolamide and benzolamide on the ionic composition of parotid saliva were studied in anaesthetized sheep with access to the parotid blood vessels. 2. The inhibitors were infused directly into the arterial blood supply to the gland to give blood concentrations in the range 10(-5) to 10(-2) M. 3. Mean anionic concentrations at basal flow rate before inhibitor infusion were, bicarbonate 98 m-mole/l., phosphate 15 m-mole/l. and chloride 26 m-mole/l. In the presence of inhibitors, bicarbonate concentration fell by 11 m-mole/ml. and phosphate and chloride concentrations rose. Secreto-motor nerve stimulation increased bicarbonate concentration by 13 m-mole/l. before infusion of inhibitors and the concentrations of the other anions fell. The bicarbonate rise was abolished by the inhibitors and the fall in phosphate concentration was balanced by a rise in chloride concentration. 4. These effects show that only a small component of the bicarbonate ion transfer system in the sheep parotid gland is sensitive to these inhibitors. 5. The relationship of these findings to a new enzyme with carbonic anhydrase action isolated from the sheep's parotid gland is discussed.

Animals↗
PubMed1980

ACTH-elicited sodium appetite in sheep.

Intramuscular injections of long-acting synthetic ACTH (45 U twice daily for 5 days) caused a large increase in the intake of 0.5 M NaCl in sheep. Mean Na intake of the sheep on the last 3 days of treatment approximated 50% of their total extracellular fluid Na. The mineral appetite was specific for NaCl. Intakes of 0.5 M KCl or 0.25 M CaCl2 were not significantly altered. The enhanced appetite for Na induced by ACTH appeared to precede any increase in urinary Na excretion. ACTH treatment was ineffective in adrenalectomized sheep. However, an infusion into adrenalectomized sheep of a combination of adrenal steroid hormones (including aldosterone, deoxycorticosterone, 11-deoxycortisol, cortisol, and corticosterone) that contrived blood levels similar to those, obtained with ACTH treatment in normal sheep did induce Na appetite. Thus, ACTH induces a specific, adrenal-steroid hormone-dependent Na appetite in sheep.

Adrenocorticotropic Hormone↗
PubMed1980

The maxillary ameloblastoma: an analysis of 24 cases.

Twenty-four cases of maxillary ameloblastoma from the files of the dental and oral division of the Armed Forces Institute of Pathology and the US Army Institute of Dental Research were reviewed. Clinical findings showed an average age of 45.6 years, a male-to-female ratio of 2.4:1, and an equal racial distribution between whites and blacks. Eighty-eight percent of the tumors occurred distal to the maxillary canine. A slowly enlarging mass was the primary clinical sign in more than 90% of the cases. Recurrences were seen in eight of the 16 cases on which follow-up information was received. The majority of the tumors had a mixed follicular histologic pattern. Therapy should consist of either surgical block excision or hemimaxillectomy. The surgeon must carefully weigh the potential danger of the neoplasm against the deformity and disability caused by the surgical procedure.

Adolescent↗
PubMed1979

Expansile lesion of the posterior maxilla in an adult male.

A case of odontogenic fibromyxoma of over 5 years' duration which was evident roentgenographically (but not diagnosed) at the time of treatment for a fractured zygoma of the ipsilateral side is presented. The rate of growth did not appear to be significantly altered by trauma. The tumor was successfully treated by enucleation and curettage with removal of the associated teeth. No evidence of recurrence was noted 6 months postoperatively.

Adult↗
PubMed1979

Collateral circulation in the rabbit tongue after common carotid ligation.

A study was undertaken to ascertain the microvascular pattern of the collateral circulation of the tongue after unilateral ligation of the common carotid artery. The right common carotid artery was ligated in 25 New Zealand White male rabbits. These animals were killed in groups of five at intervals of an hour, six hours, 24 hours, one week, and two weeks. The vasculature in the head and neck of these animals was flushed with heparinized saline solution and perfused with latex. The results show that circulation was present but signifincatly reduced in the one-hour group, slightly reduced in the six-hour and 24-hour groups, and normal in the one- and two-week groups. This study indicates that the collateral circulation of the tongue is extensive and that a normal vascular pattern returns within a week after unilateral ligation of the common carotid artery.

Animals↗
PubMed1978

Adenocarcinoma of the palate--diagnosis and management.

A case of adenocarcinoma of the palate has been presented. Emphasis has been placed on the surgical management and immediate postoperative care. Frequent postsurgical examination has been stressed to rule out evidence of recurrence or metastasis.

Adenocarcinoma↗
PubMed1978

ACTH induced sodium appetite in the rat.

Subcutaneous injections of long-acting synthetic ACTH (5 U/day) caused a large increase in the intakes of both 0.5 M NaCl and water in rats. By the fifth day of treatment the rats were turning over an amount of sodium approximating their own total body sodium. The mineral appetite was specific for NaCl. Intakes of KCl, MgCl2 and CaCl2 were unchanged. ACTH was ineffective in adrenalectomized rats suggesting that the appetite was dependent on adrenal hormones.

Adrenalectomy↗
PubMed1978

Pathosis of the hard and soft palate.

In this article a few of the more recently emphasized and pertinent conditions that may affect the hard and soft palate have been discussed. The purpose of the article is not to present in all-inclusive classification of lesions occurring the palate. Disease of the palate may be local in nature or may reflect a systemic condition. Dentists must be conscious of the palate as the site of many possible pathoses. The prosthodontist in particular must observe and carefully evaluate the palate and insure its good health before he can prescribe a prosthesis to cover it. Dentistry provides a health service which affects the entire human organism and not just the oral cavity. Therefore an understanding of the varied nature of pathosis as it relates to the oral cavity, and especially the palate, is essential. Continuous surveillance of the palatal regions insures that the dentist's obligation to detect oral abnormalities in patients is in large measure fulfilled.

Ameloblastoma↗