PubMed Health⌕ Search

Biomedical subjects

D York

Publications and source records attributed to D York.

61 records · Page 4Linked to original sources
PubMed1984

Effect of age and gene dosage on brown adipose tissue of Zucker obese fa/fa rats.

Experiments were performed to investigate the effect of age and genotype on brown adipose tissue thermogenesis in Zucker rats. Specific [3H]GDP binding to interscapular brown adipose tissue mitochondria ( IBATM ) was reduced in 14-day-old preobese fa/fa rats and remained lower after weaning. A gene-dosage effect of the recessive fa gene was observed in 8- to 10-wk-old rats in both IBATM [3H]GDP binding and the thermic effect of a balanced meal (50 kJ Complan ), measured by indirect calorimetry. In each case the heterozygote (Fa/fa) group had a value intermediate between those of obese (fa/fa) and the homozygous lean (Fa/Fa) groups. Norepinephrine increased IBATM [3H]GDP binding to similar levels in lean (Fa/fa) and obese (fa/fa) rats and induced similar increases in oxygen consumption in Fa/Fa, Fa/fa, and fa/fa rats. It is concluded that the impaired, diet-related brown adipose tissue thermogenesis is closely related to the primary gene defect in the obese rat. This defect may result from misregulation of the autonomic nervous system.

Adipose Tissue↗
PubMed1984

Further studies with a noninvasive method of intracranial pressure estimation.

A linear relationship between elevated intracranial pressure in patients with hydrocephalus and with cerebral edema and a latency shift of the N2 wave of the flash-evoked cortical potential is demonstrated. Although the relationship is good at pressures of 200 to 300 mm H2O, it is excellent at pressures above 300 mm H2O. This relationship establishes a reliable noninvasive method of estimating intracranial pressure.

Adult↗
PubMed1977

Ultrastructural effects of Helminthosporium maydis race T toxin on mitochondria of corn roots and protoplasts.

Zea mays inbred W64A in Texas (T, toxin sensitive) male sterile and non-male sterile (N, toxin resistant) cytoplasms were utilized. Roots of freshly germinated seeds were treated for 15 min of 2 hr with culture filtrate from liquid grown Helminthosporium maydis Race T, or with a chloroform extractable purified fraction from the culture filtrate. In the susceptible W64A T line, toxin treatment, both crude and purified, caused swelling and loss of matrix densiy in mitochondria of root cap and vacuolated cells in the region of elongation. One hour treatment with the chloroform extractable toxin fraction caused similar effects or mitochondria of isolated leaf protoplasts. This is the first report of such rapid in vivo effects of HmT toxin on mitochondria. Difficulty in obtaining consistent preservation of meristem mitochondria precluded drawing firm conclusions concerning that region of the root. In the resistant W64A N line, protoplast and root mitochondria were unaffected by the toxin.

Drug Resistance↗
PubMedDate not supplied

Anterior cingulate cortical transplantation in transgenic Huntington's disease mice.

Huntington's disease (HD) is an autosomal dominant disorder involving progressive neurodegeneration of the corpus striatum and cerebral cortex. Transgenic mice, in which exon 1 of the human HD gene with an expanded trinucleotide repeat is expressed, develop a neurodegenerative syndrome that closely models human HD. Transplantation of wild-type donor cortex into the anterior cingulate cortex of neonatal HD mice (R6/1 line) was found to delay the onset of a specific motor deficit, rear-paw clasping. However, transplantation did not significantly enhance motor performance on a suspended horizontal rod, a behavioural measure of fine motor co-ordination. Control experiments in which the anterior cingulate cortex was resected, but no donor cortical tissue was transplanted, showed no behavioural benefit. In fact, wild-type littermate mice that also underwent this surgical resection, were found to develop motor deficits similar to those exhibited by non-resected HD mice. These results suggest that the anterior cingulate cortex is an important area of pathology in this HD model, and that therapeutic approaches to HD may need to target cortical, as well as striatal areas.

Animals↗
PubMedDate not supplied

Geochronology, stratigraphy and geochemistry of Cindery Tuff in Pliocene hominid-bearing sediments of the Middle Awash, Ethiopia.

Cindery Tuff is a subalkaline, rhyolitic air-fall deposit that was probably produced by a mixed-magma eruption. It is a distinctive, datable, regional isochronous marker bed within the Pliocene sediments of the Middle Awash district, and is stratigraphically situated between two new fossil hominid discoveries. Based on 40Ar/39Ar analyses of plagioclase, rhyolitic glass and basaltic glass, as well as fission-track analyses of zircons, we estimate its age to be 3.8-4.0 Myr. This implies that associated hominid skull fragments are at least 3.9 Myr old.

Animals↗
PubMedDate not supplied

Insult after injury: pressure ulcers in trauma patients.

DESIGN: Nonexperimental-Descriptive. SAMPLE: The inclusion criteria were trauma patients, ages 15 and older, who were hospitalized for > 2 days, and who did not have preexisting skin breakdown. A total of 148 consecutive trauma patients admitted to the study institution meeting the inclusion criteria were prospectively enrolled. METHODS: Patients were assessed every 3 days for skin breakdown. Information on the patient's bed type, therapies, medical devices, and nutrition was collected. The Braden Scale for predicting pressure ulcer risk was completed at each assessment. FINDINGS: Of the 148 patients enrolled, 30 developed at least one area of skin breakdown for a prevalence of 20.3% in patients hospitalized more than 2 days. The most common cause of breakdown was positional pressure (47.4%). Cervical collars were the second leading cause at 23.7%, followed by tracheostomy/endotracheal tubes at 10.5%. The mobility subscale of the Braden Pressure Ulcer Risk Assessment tool was significantly predictive of skin breakdown (p < .001). IMPLICATIONS FOR NURSING RESEARCH: Skin breakdown is a significant problem in trauma patients who are hospitalized for more than 2 days. Aggressive protocols on positioning, cervical collar use, and airway adjuncts, as well as additional active nursing interventions for immobile patients, may be ways to decrease the skin breakdown prevalence in this population.

Adolescent↗