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Biomedical subjects

D J Fletcher

Publications and source records attributed to D J Fletcher.

At least 37 records · Page 2Linked to original sources
PubMed1987

Health promotion for children. Key to a lifetime of health.

Evidence indicates that preventive healthcare in childhood reduces healthcare costs and enhances health. Physicians can assume a leadership role in promoting children's health by incorporating health promotion measures into their everyday practice, serving as resource persons or leaders in community and school efforts in health promotion, and lobbying for legislation aimed at preventive care. The goals of these efforts are to achieve a healthy childhood, provide a foundation for a healthy adulthood, and develop in children positive values about personal health responsibility and use of healthcare services.

Adolescent↗
PubMed1987

Vasoactive intestinal polypeptide enhances hormone content and insulin release in cultured fetal rat islets.

The effect of porcine vasoactive intestinal polypeptide (VIP) on development of the biphasic insulin release response in cultured fetal rat islets was investigated. Fetal islets, 21.5 days gestational age, were cultured for 7 days in RPMI 1640 culture medium containing either 2.8 or 11.1 mM glucose adn subsequently challenged with 16.7 mM glucose in a perfusion system. Islets were exposed to VIP at a final concentration of 13.2 nM by adding the peptide to the perifusion buffer (acute exposure) or by adding it to the culture medium throughout the culture period (chronic exposure). Islet hormone and DNA contents were also quantitated at the end of the culture period. Acute exposure to VIP resulted in no alterations of the insulin release pattern after culture in the presence of either glucose concentration. However, chronic treatment of islets with 13.2 nM VIP in the presence of 2.8 mM glucose resulted in significant increases in the maximum rate of insulin release during the first phase and the total amount of insulin release during both phases. Similarly, islets cultured in the presence of 11.1 mM glucose and 13.2 nM VIP demonstrated enhanced biphasic insulin release patterns with increased maximum rate and total amount of release during both phases. The presence of VIP and 2.8 mM glucose increased islet glucagon and somatostatin contents, but islet DNA and insulin contents remained unchanged. These findings indicate that VIP plays a significant role in the in vitro development of the biphasic insulin release pattern and may be a factor controlling the maturation of the fetal islet in vivo.

Animals↗
PubMed1986

Coping with insomnia. Helping patients manage sleeplessness without drugs.

Sleep, a vital ingredient in life, is often taken for granted until something goes awry and sleep no longer comes easily. Occasional bouts of sleeplessness are normal, but for some persons, perhaps as much as 20% of the adult population, insomnia is a recurring problem for which they may turn to over-the-counter or prescription sleeping pills as a solution. In all but the most extreme cases, however, medication is not necessary and nondrug remedies are sufficient for lulling the patient back to sleep. In this article, Dr Fletcher describes what everyone should know about the complex process of sleep and offers suggestions, including some familiar old-fashioned home remedies, on what to do when sleep is evasive.

Animals↗
PubMed1986

The effects of vagotomy on compensatory ovarian hypertrophy and follicular activation after unilateral ovariectomy.

Following unilateral ovariectomy in the rat, the remaining ovary undergoes rapid compensatory changes including an increase in the number of antral follicles (follicular activation) and an increase in ovarian weight (compensatory ovarian hypertrophy). The ovary is innervated by the vagus nerve (Burden et al., 1983). In the present study, the effects of right and left cervical vagotomy and abdominal vagotomy on follicular activation and compensatory ovarian hypertrophy in the remaining right or left ovary were compared 15 days after unilateral ovariectomy. Neither right nor left cervical vagotomy affected compensatory ovarian hypertrophy of the right or left ovaries but abdominal vagotomy depressed compensatory ovarian hypertrophy in both the right and left ovaries. Left cervical vagotomy did not inhibit follicular activation, but right cervical vagotomy prevented follicular activation in the right but not left ovary. Also, abdominal vagotomy inhibited follicular activation in the right but not the left ovary. In animals with both ovaries which were subjected to the left or right cervical vagotomy or abdominal vagotomy follicular counts in both right and left ovaries were similar. Collectively, these data indicate that the vagus nerve participates in follicular activation after unilateral ovariectomy. The data also indicate that the right ovary is more dependent on vagal influences for follicular activation than the left ovary.

Animals↗
PubMed1986

Health-risk appraisal. Helping patients predict and prevent health problems.

Health-risk appraisals (HRAs) are self-scored questionnaires or computer programs that use demographic and risk-factor data to estimate the most likely causes of death and to provide guidance on how to reduce risk of death. The clinical usefulness of HRAs lies in their ability to motivate patients to modify negative habits and lifestyles. Still very much in a developmental stage, HRAs are not substitutes for preventive health examinations and are best used in conjunction with ongoing physician-supervised health-promotion and disease-prevention efforts.

Adult↗
PubMed1985

Diet and coronary heart disease. Helping patients reduce serum cholesterol level.

Although coronary heart disease (CHD) remains the No. 1 cause of death in the United States, the CHD mortality rate has shown a recent decline. This has been attributed to lower fat consumption in the general population, with associated lower serum cholesterol levels. Thus, diet seems to be an important factor in controlling cholesterol level. Acting on this hypothesis, primary care physicians can help patients make appropriate dietary changes. We believe that persons at risk of hypercholesterolemia need to be identified in adolescence by measurement of total serum cholesterol level and that testing should be done every two years after age 25. The American Heart Association's prudent diet is recommended for all patients, especially those with a serum cholesterol level above 240 mg/dl. When dietary restriction does not bring the level within this limit, use of cholesterol-lowering agents is considered. To be lasting, dietary change must be gradual; realistic immediate and long-term goals should be established. In addition, the diet must be nutritionally sound and the patient must receive support from family members.

Adult↗
PubMed1984

An immunocytochemical study of the pancreatic islet system of the channel catfish.

The endocrine pancreas of the channel catfish is segregated into a large primary islet and numerous smaller secondary islets. In view of cell distribution differences in mammalian islets of ventral and dorsal primordia, we have determined the percentage volumes of insulin-, glucagon-, and somatostatin-containing cells in primary and secondary catfish islets to ascertain if these islets correlated with those derived from ventral and dorsal primordia in mammals. Islets were immunocytochemically stained using antisera to anglerfish insulin, porcine glucagon, and synthetic somatostatin and volume densities were quantified on light micrographs by point-counting procedures. In both primary and secondary islets the insulin-, glucagon-, and somatostatin-containing cells comprised approximately 32%, 23%, and 38% of the endocrine cell volumes, respectively. Therefore, the cell populations did not reflect any embryological differences between the two groups of islets. In this study, the volume densities of insulin-reactive cells in the primary islet were less than previously reported, and the overall insulin staining was about one-half of that seen in mammals. The volume density of somatostatin-reactive cells in primary islets was greater than previously reported. Based on these data, primary and secondary islets of the catfish do not appear to have a similar development to the ventral and dorsal islets of the mammalian system.

Animals↗
PubMed1984

Abnormal islet and adipocyte function in young B-cell-deficient rats with near-normoglycemia.

Sprague-Dawley male rats were injected at 2 days of age with streptozotocin (SZ). At 4 wk of age the fed plasma glucose concentration of the SZ group was 151 +/- 6 mg/dl as compared with 133 +/- 4 for the control group. The fed plasma insulin values were indistinguishable, however. In response to an intraperitoneal glucose challenge the SZ group had marked glucose intolerance and virtually no rise in plasma insulin. After a meal challenge the SZ group also had glucose intolerance, but plasma insulin responses were similar to those of the control. The pancreata of the 4-wk-old rats were perfused in vitro and the SZ group had essentially no response to glucose, but did respond to arginine. Adipocytes of the 4-wk-old SZ rats had impaired glucose conversion to CO2 similar to that seen in the more hyperglycemic 6-wk-old SZ rats. Castration carried out at about 3 wk of age did not influence the hyperglycemia seen at 6 wk of age and later. These data indicate that 4-wk-old SZ rats, while having near-normal plasma glucose levels and normal plasma insulin values, have clearly abnormal B-cell and adipocyte function. With increasing age and weight gain these SZ rats develop frank hyperglycemia.

Adipose Tissue↗