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Biomedical subjects

G D Phillips

Publications and source records attributed to G D Phillips.

116 records · Page 7Linked to original sources
PubMed1970

Reflex onset of polypnoea in sheep.

1. Measurements have been made of the cardio-respiratory activities, ear and lumbar skin temperatures, and temperature of the blood in the carotid artery and jugular vein of partially shorn and unshorn sheep during mammary heating at ambient temperatures of 20/55, 15/55 and 10/55 (dry bulb temperature, degrees C/relative humidity,%).2. Heating the mammary region resulted in a marked rise in respiratory and heart rates of unshorn sheep, whereas, in partially shorn sheep, the heart rates increased without being accompanied by a similar rise in respiratory rates.3. With decrease in ambient temperature from 20 to 10 degrees C, there was a decrease in respiratory response of unshorn sheep during mammary heat treatment suggesting that the magnitude of respiratory response during mammary heat treatment depends on the environmental temperature to which the sheep is exposed.4. The carotid blood temperature declined following mammary heat treatment at all ambient temperatures studied, both in unshorn and partially shorn sheep, but the magnitude of decline was greater in unshorn than in partially shorn sheep.5. The rise in respiratory rates following mammary heating of unshorn sheep at all ambient temperatures, in spite of a decline in carotid blood temperature and the absence of similar responses during flank heating, is attributed to the stimulation of warm receptors in the mammary region.

Animals↗
PubMed1966

Sodium depletion of pregnant ewes and its effects on foetuses and foetal fluids.

1. Some effects of sodium depletion were investigated in sheep at different stages of pregnancy ranging from 55 to 139 days. Sodium depletion was induced by draining the saliva from one parotid gland for a period of 6 days. Foetal samples were collected at the end of the depletion period.2. Sodium depletion of the ewe resulted in a fall in saliva Na(+) level and a rise in saliva K(+) level, a fall in plasma Na(+) and K(+) levels, a 35% reduction in plasma volume and a 16% reduction in body weight.3. In the Na(+) depleted ewes the sodium levels of the foetal plasma and amniotic fluid were lower and the volume of the allantoic fluid greater than those in the control ewes.4. It is concluded that sodium depletion of the ewe leads to a deficiency of sodium in the foetus.5. On the basis of these experiments and other reports it is postulated that a sodium deficient foetus, like a sodium deficient adult, responds to the deficiency by restricting sodium losses in the urine and by excreting water.

Amniotic Fluid↗
PubMedDate not supplied

Organ weights, liver constituents, and serum components in growing chicks fed ochratoxin A.

Chicks were fed diets containing 0, 1, 5 and 10 mg/kg ochratoxin A (OA) over a four-week period to study the effects of OA on growth, weight of internal organs, liver RNA, DNA, protein, and glycogen and serum enzymes. Ochratoxin A depressed the rate of growth and relative weight of the bursa of Fabricius, and increased the relative weights of the liver, kidney, pancreas, and various sections of the gastrointestinal tract, but had no effect on the heart and spleen. Concentrations of liver RNA, DNA and protein were decreased while glycogen was increased. Serum alkaline phosphatase and gamma-glutamyl transferase activities, and uric acid and creatinine concentrations were elevated while serum proteins, albumin, phosphorus, potassium, and cholesterol were depressed. The effects of OA were time- and dose-dependent.

Animal Feed↗
PubMedDate not supplied

Rabbit cornea assay of angiogenesis: methodology and evaluation.

The rabbit cornea angiogenesis assay has been used extensively to determine the capacity of cells, tissues, growth factors, and a variety of other compounds to stimulate the formation of capillaries. Improper use of the assay coupled with lack of thorough evaluation has generated disparate, perplexing, and even erroneous results. The objective of this article is to review the corneal angiogenesis assay, paying close attention to specific techniques, modes of evaluation, and considerations that investigators need to make before drawing any conclusions.

Journal Article↗
PubMedDate not supplied

Trace element balance in adults receiving parenteral nutrition: preliminary data.

There have been many recommendations regarding trace element needs of adults receiving total parenteral nutrition. Balance studies for zinc, copper, manganese, chromium, selenium, and molybdenum were carried out in 3 critically ill patients in an intensive care unit. Results indicate that the need for zinc was great in them, but that for copper and manganese was lower. Small negative chromium and selenium balances were observed. Molybdenum, iron, cobalt, and iodine balances were attempted but proved difficult to interpret. The requirement of each trace element varied from patient to patient, and was influenced by the presence of gastrointestinal fluid loss and renal function.

Adult↗
PubMedDate not supplied

Platelet derived wound healing factors (PDWHF) accelerate and augment wound healing angiogenesis in the rat.

The object of this study was to determine the effect of PDWHF on wound healing angiogenesis. Sponges saturated with PDWHF were implanted in rats. Six hours to 14 days post-implantation, vascular corrosion casts were prepared and examined by SEM. Leukocyte margination and angiogenesis was accelerated by 24-48 hours. Vessel number was also greater than in the controls. Another series of PDWHF treated sponges were implanted. Fourteen days later the vasculature was perfused with Evans blue. Sponges were homogenized, and absorbance of the supernatants was determined. Absorbances of PDWHF supernatants was 2X greater than controls. PDWHF enhanced wound healing angiogenesis in the rat.

Animals↗
PubMedDate not supplied

Vascular endothelial growth factor (rhVEGF165) stimulates direct angiogenesis in the rabbit cornea.

The object of this study was to test vascular endothelial growth factor (VEGF) for angiogenic activity in the rabbit corneal assay. VEGF doses ranging from 20 ng to 1000 ng were incorporated into a slow release polymer and implanted into the avascular rabbit cornea. Capillary formation in the cornea was visually analyzed on a daily basis and examined with histology, transmission electron microscopy and scanning electron microscopy of vascular corrosion casts on days 2 and 7 post-implantation. VEGF implants (200ng to 1000ng) consistently stimulated angiogenesis. This neovascularization occurred in the absence of inflammation. We conclude that VEGF acts directly on endothelial cells, initiating and mediating the formation of capillaries.

Animals↗