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Biomedical subjects

B H Johnson

Publications and source records attributed to B H Johnson.

143 records · Page 8Linked to original sources
PubMed1975

Effects of selection for postweaning gain on testicular function in mice.

Changes in testicular and epididymal function and selected endocrine organ size were examined in a line of mice selected for rapid postweaning gain (M16) and in reciprocal crosses with an unselected pedigree control line (ICR). The larger body weight of the M16 line was accompanied by larger testes, epididymides, seminal vesicle, pituitary, thyroid and adrenal weights (P smaller than .01) although the testes, epididymides, seminal vesicle and adrenal weights of M16 mice, expressed per gram body weight, actually decreased (P smaller than .01) relative to the ICR line. Testicular and epididymal sperm reserves were higher in M16 mice but the difference was not significant. However, when adjusted for gland size, testicular and epididymal sperm reserves were lower in the M16 line (P smaller than .01). Absolute and relative weights of testes, epididymides and pituitary were larger (P smaller than .01) in M16 male times ICR female crosses than in ICR male times M16 female crosses. Although testicular and epididymal sperm reserves were higher in M16 male times ICR female males the reciprocal difference was significant only for testicular sperm (P smaller than .05). Heterotic effects were significant for both absolute and relative weights of testes, epididymides (P smaller than.01), pituitary (P smaller than .05) and relative weight of siminal vesicles (P smaller than .05). Although percent heterosis was 8.5 for testicular and epididymal sperm reserves, significant heterotic effects were found only for epididymal sperm (P smaller than .05).

Adrenal Glands↗
PubMed1971

Follicle-stimulating hormone and the regulation of testosterone secretion in rabbit testes.

Regulation of testosterone secretion is presumably mediated by interstitial cell-stimulating hormone (ICSH). However, there is little information on the actions of other chemical messengers in regulating testosterone secretion. We have shown that follicle-stimulating hormone augments testosterone secretion stimuated by ICSH in rabbit testes perfused in vitro with an artificial medium.

Animals↗
PubMedDate not supplied

Effect of adrenal steroids on testosterone and luteinizing hormone secretion in the ram.

The effects of adrenal steroids on testosterone and LH secretion and changes in serum cortisol levels in response to treatments were studied in the ram. Acute administration of synthetic ACTH (10 micrograms/kg BW) elevated (P less than 0.01) serum cortisol and transiently suppressed (P less than 0.05) serum testosterone and LH. Acute dexamethasone treatment suppressed (P less than 0.01) serum cortisol, testosterone and LH. Administration of vehicle had no effect (P greater than 0.10) on serum hormone levels. These data support the contention that adrenal steroids inhibit testicular endocrine function indirectly by acting at the hypothalamic or pituitary level because both ACTH and dexamethasone treatments suppressed serum LH. To differentiate between hypothalamic and pituitary sites of action, the pituitary and testicular responses to an LHRH challenge (100 micrograms) were examined in rams chronically treated with dexamethasone (5 mg i.m., twice daily for 5 days). This treatment regimen suppressed (P less than 0.01) serum cortisol levels. Compared with controls, basal testosterone levels were suppressed (P less than 0.05) in dexamethasone-treated rams; however, no effect (P greater than 0.10) on the magnitude of the testosterone response to LHRH or on either basal or LHRH-stimulated LH secretion was observed. Thus, although a direct testicular effect cannot be eliminated, these data suggest that, in the ram, adrenal steroids inhibit testicular endocrine function by action at the level of the hypothalamus.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Glucocorticoids, oxysterols, and cAMP with glucocorticoids each cause apoptosis of CEM cells and suppress c-myc.

In clones of the CEM human acute lymphoblastic leukemic cell line, glucocorticoids, oxysterols and activators of the cAMP pathway acting synergistically with glucocorticoids, each can cause apoptotic cell death. Morphologically and kinetically, these deaths resemble one another. The kinetics are striking: in each case, after addition of the lethal compound(s), an interval of approximately 24 h follows, during which cell growth continues unabated. During this "prodromal" period, removal of the apoptotic agent leaves the cells fully viable. We hypothesize that a sequence of biochemical events occurs during the prodrome which eventually results in the triggering of the full apoptotic response as evidenced by the activation of caspases and DNA fragmentation. At some point, the process is irreversible and proceeds relatively rapidly to cell death. Suppression of c-Myc seems a universal early event evoked by each of these lethal compounds or combinations, and we conclude that the negative regulation of this proto-oncogene is an important aspect of the critical pre-apoptotic events in these cells.

Apoptosis↗
PubMedDate not supplied

Correlated responses in male reproductive traits in mice selected for litter size and body weight.

Correlated responses in male reproductive traits were determined at 4, 6 and 8 weeks of age in lines of mice selected for large litter size (L+), large 6-week body weight (W+), large litter size and small body weight (L+W-) and small litter size and large body weight (L-W+), and in an unselected control (K). Concentration of serum testosterone and weights of testes, seminal vesicles, epididymides and adrenal glands increased with age. Line differences in testosterone concentration were not detected. L+ and W+ males exhibited positive correlated responses in testes, epididymides and seminal vesicle weights. Testis weight adjusted for body weight was significantly larger for L+ than controls and approached significance for W+. Realized genetic correlation be-testis weight and litter size was 0.60 +/- 0.04, and the realized partial genetic correlation holding body weight constant was 0.42. Therefore, pleiotropic loci, acting via the hypothalamic-pituitary axis, affect testis weight and litter size independently of body weight. Additionally, genes influencing overall growth have a pleiotropic effect on testis weight and litter size in mice; the realized genetic correlations of body weight with testis weight and with litter size were 0.60 +/- 0.03 and 0.52 +/- 0.10. Testis weight increased in both L+W- and L-W+ males. The positive correlated response in L+W- may have resulted from changes in frequency of genes controlling reproductive processes; whereas, in L-W+ it could have been the result of changes in the frequency of genes associated with body weight.

Adrenal Glands↗
PubMedDate not supplied

New mutation causing jaundice in mice.

A new mutant causing jaundice in mice is reported. Allelism tests indicate that it is not allelic with known hemolytic anemia mutants in mice [hemolytic anemia (sphha), jaundiced (ja), normoblastic anemia (nb), and spherocytosis (sph and sph2Be)]. The jaundiced condition appears in young mice at about 24 hours postpartum and is due to a major increase in unconjugated bilirubin in serum compared to normal controls. Adult mutant mice are not jaundiced and bilirubin levels do not differ from normal mice. Adult male mutants have reduced testes size and no viable sperm. Female mutants are fertile but overall maternal performance is reduced as indicated by increased mortality and reduced growth rate of pups. Genetic tests indicate that a single autosomal recessive gene is responsible for the condition. We propose that the mutant be designated hyper-unconjugated bilirubinemia, with the gene symbol hub.

Animals↗
PubMedDate not supplied

Technology and family-centered perinatal care: conflict or synergy?

Advances in technology have dramatically changed health care delivery and the experience of patients and families during the past 2 decades. Accompanying the explosion of new technology, particularly in perinatal and pediatric settings, has been movement toward humanizing the health care environment through an emphasis on family-centered care. The impact technology has had on patients, families, and caregivers is reviewed, and the evolution of family-centered care in relation to technological progress is chronicled. Recommendations are provided for ways in which technology and family-centered care can work together to improve perinatal health care.

Family↗
PubMedDate not supplied

Do volatile anesthetics act as ideal gases?

Under conditions of temperature and pressure commonly found in operating rooms, the anesthetics enflurane, halothane, and isoflurane act as nearly ideal gasses even at concentrations producing a saturated vapor phase. The deviations from ideality are 3.44 +/- 0.44% (SEM) for enflurane, 0.94 +/- 0.30% for halothane, and 2.96 +/- 0.29% for isoflurane. That is, 0.9 to 3.4% more anesthetic is vaporized than would be predicted from the vapor pressure of these agents.

Anesthesiology↗
PubMedDate not supplied

Nitrous oxide: effect on accumulation rate and uptake of bowel gases.

Breathing 79% nitrous oxide (N2O) in oxygen increased the rate of accumulation of bowel gas during intraluminal bowel segment infusions of hydrogen, methane (CH4), air, or carbon dioxide (CO2) in four pentobarbital-anesthetized dogs more than did breathing 100% oxygen. A N2O-associated increase in the volume of naturally produced intestinal gas in five halothane-anesthetized ponies corroborated the findings in the dog studies. In a second group of four dogs a bolus of CH4 or CO2 was injected into the bowel lumen. When the dogs breathed O2 the bowel gas volume decreased. Gas was virtually absent in the CO2-containing segment within 20 minutes. Breathing N2O increased the volume of the segments containing CH4 while the CO2 segments decreased less rapidly than during O2 breathing. Breathing O2 after 30 minutes of N2O breathing caused little change in the rate of decrease in CO2 segment volumes. However, the CH4 segment volume ceased to increase and eventually returned toward control volumes.

Air↗
PubMedDate not supplied

Family-centered care: facing the new millennium. Interview by Elizabeth Ahmann.

In an interview with the column editor, Beverley Johnson, President and Chief Executive Officer of the Institute for Family-Centered Care, shares her views on the state of family-centered care (see Table 1). A notable achievement over the past several decades has been the acknowledgment of family-centered care as the standard of care for children with special health care needs. Today there is a growing momentum to more broadly apply the principles of family-centered care in both pediatric and adult care settings, and much work needs to be done to build on the strong foundation that has been laid. Changing attitudes and practice, changing how families are viewed and how care is provided, developing collaborative approaches, and emphasizing the importance of relationships--changing in these ways the very culture of health care--will be necessary to make family-centered care a full reality. Many of these changes need to begin during the process of educating medical and nursing students. Health care institutions can support these changes by incorporating principles of family-centered care into personnel policies and practices, ensuring the hiring and support of individuals with family-centered skills and attitudes, and rewarding family-centered practice. Many of these changes can also be supported by research on the relationships between family-centered care and health care utilization, lengths of stay, and health care outcomes. The interview concludes as follows: "What is good for families and patients is often good for the health care system as well. Family-centered care is a winning proposition for all concerned."

Adult↗
PubMedDate not supplied

New guidance materials promote family-centered change in health care institutions.

Nurses can play an important role as effective change agents in helping health care agencies and institutions recognize the need to move to more family-centered models, understand the benefits of a family-centered approach, and develop strategies for implementing family-centered care. The Institute for Family-Centered Care has identified a number of areas in which many institutions wish to make changes and has been developing guidance materials that explore possibilities, highlight hospitals that have incorporated changes, and provide practical strategies and useful materials to facilitate change. Topics covered in these guidance resources include the following: Developing Family-Centered Vision, Mission, and Philosophy of Care Statements; Developing and Sustaining a Patient and Family Advisory Council; Collaborative Design Planning; Creating Children's Advisory Councils; Creating and Enhancing Patient and Family Resource Centers; Creating Patient and Family Faculty Programs; Working with Seniors and their Families to Enhance Geriatric Care; and Changing Visiting Practices--Families as Partners.

Delivery of Health Care↗
PubMedDate not supplied

Children's drawings as a projective technique.

Body image is the constantly changing mental picture of one's body. The examination of children's drawings provides an insight into cognitive and psychosocial functioning, which are important aspects in their development of self-concept.

Art↗