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Biomedical subjects

J Nichols

Publications and source records attributed to J Nichols.

At least 91 records · Page 5Linked to original sources
PubMed1987

Food intake at age 8. 2. Frequency, company and place of meals.

In a sample of 141 healthy 8 year old children, over 95% had three main meals on each of the 4 days of the food record. Two-thirds had an afternoon snack and nearly one-half a morning snack on each of the 4 days, but only one-quarter had supper on each day. Seventy-one per cent of all meals were eaten at home with the family, 20% at school with friends, and less than 1% of meals were eaten at a restaurant or fast food outlet. These data show that amongst children of primary school age, take away sources of food make a very small contribution to the diet, and that eating habits at home are of greatest importance to the child's diet.

Child↗
PubMed1987

Food intake at age 8. 3. Distribution and food density by meal.

This report describes how nutrient intake was distributed throughout the day, and the nutrient density according to meal, in 78 boys and 63 girls who have been studied from birth. The food intake was calculated from 4 day weighed records using the CSIRONET data bank based on British tables of food composition. The percentages of total energy from breakfast, lunch, evening meal, and snacks were 20, 26, 31, 23%. There was a very wide range of individual nutrient intake for each meal. The evening meal made the largest contribution to fat and protein intake. Most starch came from lunch (30%) and least from snacks (16%). Snacks contained a large portion of the simple sugars (39%). Breakfast was an important source of calcium and B vitamins, but with wide ranges of micronutrients occurring for each meal. This analysis of nutrient density and distribution contributes towards the formulation of practical recommendations about beneficial dietary changes.

Child↗
PubMed1987

Effects of insulin infusion on human skeletal muscle pyruvate dehydrogenase, phosphofructokinase, and glycogen synthase. Evidence for their role in oxidative and nonoxidative glucose metabolism.

To determine whether activation by insulin of glycogen synthase (GS), phosphofructokinase (PFK), or pyruvate dehydrogenase (PDH) in skeletal muscle regulates intracellular glucose metabolism, subjects were studied basally and during euglycemic insulin infusions of 12, 30, and 240 mU/m2 X min. Glucose disposal, oxidative and nonoxidative glucose metabolism were determined. GS, PFK, and PDH were assayed in skeletal muscle under each condition. Glucose disposal rates were 2.37 +/- 0.11, 3.15 +/- 0.19, 6.71 +/- 0.44, and 11.7 +/- 1.73 mg/kg X min; glucose oxidation rates were 1.96 +/- 0.18, 2.81 +/- 0.28, 4.43 +/- 0.32, and 5.22 +/- 0.52. Nonoxidative glucose metabolism was 0.39 +/- 0.13, 0.34 +/- 0.26, 2.28 +/- 0.40, and 6.52 +/- 1.21 mg/kg X min. Both the proportion of active GS and the proportion of active PDH were increased by hyperinsulinemia. PFK activity was unaffected. Activation of GS was correlated with nonoxidative glucose metabolism, while activation of PDH was correlated with glucose oxidation. Sensitivity to insulin of GS was similar to that of nonoxidative glucose metabolism, while the sensitivity to insulin of PDH was similar to that of glucose oxidation. Therefore, the activation of these enzymes in muscle may regulate nonoxidative and oxidative glucose metabolism.

Glucose↗
PubMed1987

Aerodynamic control in apraxia at three intraoral pressure levels.

Five neurologically normal and five apractic subjects were required to develop and maintain target intraoral pressure levels during 5-sec. trials. The apractic subjects showed increased latencies in gaining the target and reduced maintenance time and increased variability in attempts to stay at target. Results suggest that physiologically based assessment tasks provide sensitive indices of the degree of oral apraxia in patients with left-hemisphere brain damage.

Aphasia↗
PubMed1987

Asthma mortality.

These discussions are selected from the weekly staff conferences in the Department of Medicine, University of California, San Francisco. Taken from transcriptions, they are prepared by Drs Homer A. Boushey, Professor of Medicine, and David G. Warnock, Associate Professor of Medicine, under the direction of Dr Lloyd H. Smith, Jr, Professor of Medicine and Associate Dean in the School of Medicine. Requests for reprints should be sent to the Department of Medicine, University of California, San Francisco, School of Medicine, San Francisco, CA 94143.

Aged↗
PubMed1986

A proposal for tracking health care for the homeless.

The number of homeless in the nation has increased rapidly during the first half of this decade. These two million homeless individuals are at high risk for health problems since they lack the essentials to remain healthy. Several large cities have developed and implemented health care programs to alleviate the problem of the homeless in America. However, most of these programs have been instigated solely by health care providers who have differing goals, values, and beliefs about health care than those they purport to serve. These differing perspectives give rise to an array of health care utilization/accessibility problems including coordination and continuity of care. To address some of these problems of coordination, a Tool for Referral Assessment of Continuity (TRAC) has been developed for assisting a complex health care system in the referral and tracking of homeless clients. A description of the TRAC is included here.

Delivery of Health Care↗
PubMed1986

Dibutyryl cyclic adenosine monophosphate reduces expression of c-myc during HL-60 differentiation.

The human promyelocytic leukemia cell line HL-60 is induced to differentiate along a myelocytic pathway by dibutyryl cyclic adenosine monophosphate (dbcAMP). Other cAMP analogs are ineffective as inducing agents. The effect of these compounds on expression of c-myc was investigated using a DNA probe for c-myc to detect RNA transcripts. The dose response and time to commitment for reduction in c-myc expression with dbcAMP was similar to the findings for phenotypic changes. Bromo-cyclic AMP and butyrate alone caused no changes in c-myc expression in 24 hours, but demonstrated dramatic synergism together, suggesting that butyrate contributes in part to the effects of dbcAMP. Evidence for mechanisms of action of cAMP other than activation of the cAMP-dependent protein kinase is reviewed.

Bucladesine↗
PubMed1986

Calcification of subcutaneously implanted type I collagen sponges. Effects of formaldehyde and glutaraldehyde pretreatments.

Although collagen-containing implants are widely used in various surgical applications, there has been relatively little attention paid to the possibility that this type of biomaterial may undergo pathologic calcification which could compromise its function. The present study reports for the first time the calcification of a series of implants of purified collagen sponges prepared with graded degrees of aldehyde-induced cross-linkages (assessed by shrinkage-temperature, wetting time, and collagenase digestibility). Type I collagen sponges were pretreated with either glutaraldehyde (0.1% to 2.0% aqueous solution, for 5-180 minutes) or formaldehyde (as vapors for 15 minutes to 15 hours), and implanted subcutaneously for 21 days in weanling rats. Although specimens not pretreated with either aldehyde reagent and the formaldehyde sponges pretreated for 15 minutes were resorbed without evidence of calcification, all other aldehyde-pretreated implants mineralized. The degree of calcification did not correlate with extent of cross-linking. Formaldehyde-pretreated implants calcified more extensively (Ca2+ = 87.8 +/- 2.8 micrograms/mg, mean +/- standard error of the mean; n = 58) than did glutaraldehyde-pretreated implants (Ca2+ = 40.9 +/- 1.4 micrograms/mg; n = 52). It is concluded that both glutaraldehyde- and formaldehyde-pretreated Type I collagen sponges calcify after subdermal implantation in young rats. Although aldehyde pretreatment of Type I collagen sponge implants is a prerequisite for their eventual mineralization, the threshold level of aldehyde-induced cross-linking required to potentiate their maximal pathologic calcification is low.

Aldehydes↗
PubMed1986

Punch biopsy wounds treated with Monsel's solution or a collagen matrix. A comparison of healing.

Adjacent punch biopsy wounds in 20 subjects were treated with a collagen matrix or Monsel's solution. Both techniques were easy to use and were hemostatically effective. The collagen matrix produced less inflammation, had a lower incidence of wound infection, was associated with a faster reepithelialization rate, and healed with a modestly better appearance at four weeks than did Monsel's solution.

Biopsy↗
PubMed1985

Radial gradient culture on the inner surface of collagen tubes: organoid growth of normal rat bladder and rat bladder cancer cell line NBT-II.

Radial histophysiologic gradient culture uses thin walled, permeable collagen tubes to house inocula in the form of either tissue explants, aggregates of cells, or dissociated cells. The outgrowth from these inocula spreads on the inner surface of the cylindrical tube, completely lining the lumen. Metabolites are exchanged through the wall of the collagen tube by diffusion from the pool of medium surrounding the cylinder. Urothelial cells form organoid stratified epithelium. A histophysiologic gradient occurs with the basal surface of the epithelium attached to the collagen wall. At this interface, for normal bladder, the initiation of epithelial renewal is seen in the basal zone, as shown by incorporation of tritiated thymidine. The simulation of conditions in nature is attained by the exchange of metabolites between the pool of medium and the basal zone of the epithelium. NBT-II appears as two concentric stratified epithelia. Isotopic labelling is seen throughout the epithelium attached to the collagen membrane. In the superficial stratified epithelium remnants of nuclei are seen without isotopic labelling. Preparation of living cultures and, after fixation, of histologic sections is technically easy.

Animals↗
PubMed1985

Epidermoid cyst of testis: a report of 3 cases.

We report 3 cases of simple epidermoid cyst of the testis. These tumors often are mistaken clinically for malignancy. Conservative surgical treatment with preservation of the testis is desirable when preoperative ultrasound reveals a well demarcated cystic nodule confirmed by histological frozen sections.

Adolescent↗
PubMed1985

Dermal wound repair: role of collagen matrix implants and synthetic polymer dressings.

The effects of two different polymeric wound dressings and a new collagen matrix (CM) implant on the healing and scarring of full-thickness excision wounds were studied in swine. The synthetic polymers comprised an occlusive O2-impermeable hydrocolloid dressing (HCD) and an occlusive O2-permeable polyurethane film (PUF). The CM implant consisted of an acellular collagen sponge fabricated from purified bovine tendon type I collagen. Wounds were evaluated for granulation tissue--production capacity by measuring 14C proline incorporation into collagenase-sensitive protein. Epidermal resurfacing and wound contraction were measured by computerized morphometric image analysis of wounds made on a tattooed grid. In comparison with air-exposed wounds, the relative collagen synthetic capacity was greater in the granulation tissue of wounds treated with HCD, PUF, or CM with occlusion. Both HCD and PUF accelerated by 40% the epidermal resurfacing over the granulating wound bed. Wound contraction was significantly reduced by CM but was not altered by the occlusive dressings.

Animals↗
PubMed1984

Effect of meningomyelocele closure on the intracranial pulse pressure.

Intracranial pressure (ICP) was monitored in a 12-year-old child before and after closure of a large, skin-covered meningomyelocele. Significant cerebrospinal fluid pulse pressure augmentation was observed over a spectrum of pressures following sac closure. Linear regression analysis was done to define pulse pressure-ICP relationships before and after surgery, and a significant increase in the regression slope was noted postoperatively. It is suggested that the unoperated meningomyelocele defect served as a shock absorber to dampen the intracranial pulse pressure. Meningomyelocele closure removes this shock absorber effect, resulting in pulse pressure augmentation.

Blood Pressure↗
PubMed1984

Heterogeneous differentiation of external cells in individual isolated early mouse inner cell masses in culture.

Inner cell masses (ICMs) were isolated from early blastocysts by immunosurgery and incubated in a dense suspension of melanin granules for 3 h after 21 h in culture. The majority of such labelled ICMs subsequently formed outgrowths in vitro in which either giant cells or small solitary cells contained melanin granules. However, a substantial minority produced outgrowths in which both types of cell were unequivocally labelled. Labelled cells appeared from the results of control experiments to have originated within the external layer of the ICM. The giant cells were indistinguishable morphologically from those formed by authentic trophectodermal tissue. The small cells were identified as belonging to the extraembryonic endodermal lineage on the basis of their distribution in host conceptuses following injection into blastocysts. These findings support the conclusion reached in previous studies that early ICM cells can engage in trophectodermal differentiation under certain conditions. In addition, by providing evidence that both trophectoderm and endoderm cells can differentiate from the outer layer of the same ICM, they argue that loss of cellular lability is not coordinated throughout this tissue. Heterogeneity in the differentiation of external cells may depend on differences in both the stage of the mitotic cycle and the number of such cycles that they have completed since fertilization. Finally, cell number in isolated early ICMs was found to increase approximately two-fold during the first 24 h of culture in the present experiments. This contrasts with the results of previous experiments in which cell number either increased more modestly or failed to do so altogether.

Animals↗
PubMed1983

Variations of dietary-induced thermogenesis and body fatness with aerobic capacity.

Resting metabolic rate (RMR), dietary thermogenesis (DIT), aerobic capacity (VO2 max), and percent body fat were measured in a group of sixteen women and ten men. DIT was significantly positively correlated with aerobic capacity (r = 0.658). Percent body fat was significantly negatively correlated with VO2 max (r = -0.727). RMR was independent of VO2 max, or body fatness, but women had a significantly higher average RMR than men. Three men and three women participated in an endurance training program which significantly increased VO2 max. DIT was increased in proportion to the increase in aerobic capacity (rs - 0.924), RMR was unchanged, and body fat decreased in males but not females. The controversy surrounding "luxuskonsumption" may stem in part from not taking into account individual differences in aerobic capacity when measuring DIT.

Adipose Tissue↗