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Biomedical subjects

R W Phillips

Publications and source records attributed to R W Phillips.

At least 163 records · Page 9Linked to original sources
PubMed1979

Genetic selection for diabetogenic traits in Yucatan miniature swine.

Yucatan miniature pigs have been selectively bred for reduced and increased glucose clearance during an intravenous glucose tolerance test. Pigs with low glucose clearance rates (low K) have been selected through the F-5 generation. They have a significantly reduced rate of glucose clearance and a blunted peripheral IRI increase in response to the challenge. Through the F-5 generation, heritability of glucose tolerance is estimated at 0.26. Sporadic fasting blood glucoses in excess of 100 mg/dl are seen in later generations of this group. High glucose clearance pigs (high K) have been selected through the F-4 generation. They have significantly increased rates of glucose clearance and a greater increase in peripheral IRI than the low K animals. The estimated heritability for high K through the F-4 generation is 0.31. No evidence of fasting hypo- or hyperglycemia has been seen in the high K animals.

Animals↗
PubMed1978

Pathophysiologic changes due to coronavirus-induced diarrhea in the calf.

Extensive water, sodium, chloride, bicarbonate, and potassium losses occur in the diarrheal calf. The water loss is entirely from the extracellular space. In severe cases, hypovolemic shock occurs with the blood volume decreased by as much as one-half. Acidosis, which results from fecal bicarbonate loss, lactic acidosis, and renal dysfunction, results in tissue buffering, which in turn causes the efflux of cellular potassium ions. Although there is a total body potassium deficit, plasma potassium concentration is increased. This, in conjunction with an intracellular deficit, causes weakness, lethargy, and potassium cardiotoxicosis resulting in death. Hypoglycemia also contributes to the weakness and lethargy seem as calves become moribund. These losses from the body and shifts in fluids and electrolytes must be understood to develop the most effective rationale for supportive therapy.

Acidosis↗
PubMed1978

A method for assessing the clinical solubility and disintegration of luting cements.

A test was designed for evaluating the distintegration of cementing agents in the oral cavity. The cements were placed in small holes located in the proximal surfaces of cast gold restorations so that the materials were not subject to abrasion. Each cement was placed in one hole located occlusally and one located gingivally. Four commercial cements of four different types (zinc phosphate, zinc silicophosphate, polycarboxylate, and EBA-Alumina zinc oxide/eugenol) were tested in 15 patients, and differences were observed in the deterioration rates of the different cements over the 6 month period. The disintegration rate of a given cement was the same in the gingival and occlusal positions. No correlation was observed between the clinical data on loss of material and the solubility of the cements as measured by conventional in vitro tests.

Aluminum↗
PubMed1978

A comparison of pin-retained amalgam and composite resin cores.

The 24 hour tensile loads required to separate the core material and dentin produced the following results: 1. No statistical difference was found between the tensile strength of retained amalgam and composite resin core materials. 2. Generally, no statistical difference was found between the retentive ability of three and four pins. 3. No statistical difference was found between the retentive ability of regular pins and minim pins if three or more pins were employed. 4. As the number of regular pins was increased beyond three, and when four minim pins were used, there was a very significant increase in dentin fracture.

Composite Resins↗
PubMed1978

Effect of fatty acids on isolated ovine pancreatic islets.

A procedure was developed for the isolation of intact islets of Langerhans from sheep pancreas. The pancreas was disrupted by syringe injection of Hanks solution followed by collagenase incubation and islet separation by sedimentation. The islets were incubated in varying concentrations of glucose and butyrate. The rate of insulin release was approximately linear while the glucose and butyrate concentrations were increased. In additional studies at 2.5 and 5.0 mM levels of substrate concentration, the stimulation of insulin had the following pattern: octanoate greater than hexanoate greater than butyrate, whereas beta-hydroxybutyrate, lactate, acetate, and propionate had only slight stimulatory effects that were not statistically significant. Decanoate did not alter insulin release from isolated islets. These data confirm earlier in vivo reports that fatty acids stimulate pancreatic hormone release in sheep and that the stimulus is related to chain length of the fatty acid through C-8 but that C-10 has no effect. A hypothesis was suggested to explain these results based on chain length, solubility, and plasma membrane alterations.

Animals↗
PubMed1978

Dental porcelain/Ni alloy interface reactions and their effective prevention.

In a Be-bearing Ni alloy porcelainized without preoxidation, Be diffuses to the interface, oxidizes, and oxygen is supplied by the atmosphere at the porcelain surface and by reduction of SiO2 at the porcelain-alloy interface. On the alloy side of the interface, pits develop locally and near them Ni and Cr oxidize. In the oxide, Ni and Si are reduced to form nickel silicides. Preoxidation of the alloy prevents Be oxidation and Si reduction for several hours of porcelainization.

Beryllium↗
PubMed1978

An in vitro study of certain properties of a glass ionomer cement.

A glass ionomer cement was tested for its release of fluoride, effect on solubility of enamel, bond to enamel, and ability to seal the cavity. It was comparable to silicate cement in its release of fluoride and its effect on solubility of enamel. The strength of the bond of the cement to tooth structure was similar to polycarboxylate cement, and it appeared to be quite effective in sealing cavities.

Acrylic Resins↗
PubMed1978

Serologic and hematologic values of bison in Colorado.

Recent economic and aesthetic interest in North American bison (Bison bison) has lead to increased interstate transport of these animals. Serologic and hematologic standards for bison are needed to detect disease in transported animals as well as within herds. This paper describes variation in blood physiological parameters in bison caused by variations in diet and season. Blood was taken from six bison and analyzed for serologic and hematologic parameters. Significant variation was found in blood urea nitrogen, chloride, cholesterol, creatinine, eosinophil, glucose, hemoglobin, lactic dehydrogenase, leukocyte, packed cell volume, potassium, serum globulin, serum glutamic oxalacetic transaminase, SGPT, and sodium levels between animals receiving a high energy-high nitrogen diet and animals receiving a low energy-low nitrogen diet.

Animals↗
PubMed1978

Escherichia coli shock in the baboon and the response to adrenocorticosteroid treatment.

Results of recent studies from this laboratory have demonstrated that methylprednisolone sodium succinate increases the survival rate of dogs given LD100 Escherichia coli endotoxin. This study was undertaken to determine the effects of methylprednisolone on the baboon infused with live Escherichia coli organisms. Awake baboons were paired by infusing intravenously comparable doses of Escherichia coli during a five hour period. Baboons given methylprednisolone received bolus injections of 30 milligrams per kilogram at 15 minutes after beginning the infusion of Escherichia coli and two hour infusions of 15 milligrams per kilogram at two hour intervals until death or for a 24 hour period. The mortality was unaltered by methylprednisolone. Six of seven baboons that were dying became progressively hypoglycemic, while hypoinsulinemia occurred in all baboons within six hours and was sustained until death. Systemic hypotension was observed. although pressures were variable. Potassium and lactate concentrations increased, while pH remained relatively constant in most baboons. Serum glutamic-pyruvic transaminase and arginase concentrations rose in most baboons dying with 18 hours. Results of morphologic studies revealed the presence of fibrin thrombi in the liver, kidney and adrenal tissue in most baboons. No significant differences in physiologic, metabolic, hematologic or morphologic parameters were observed between treated and untreated baboons.

Animals↗