PubMed Health⌕ Search

Biomedical subjects

R A Frey

Publications and source records attributed to R A Frey.

18 recordsLinked to original sources
PubMed2000

Function for Hedgehog genes in zebrafish retinal development.

The hedgehog (hh) genes encode secreted signaling proteins that have important developmental functions in vertebrates and invertebrates. In Drosophila, expression of hh coordinates retinal development by propagating a wave of photoreceptor differentiation across the eye primordium. Here we report that two vertebrate hh genes, sonic hedgehog (shh) and tiggy-winkle hedgehog (twhh), may perform similar functions in the developing zebrafish. Both shh and twhh are expressed in the embryonic zebrafish retinal pigmented epithelium (RPE), initially in a discrete ventral patch which then expands outward in advance of an expanding wave of photoreceptor recruitment in the subjacent neural retina. A gene encoding a receptor for the hedgehog protein, ptc-2, is expressed by retinal neuroepithelial cells. Injection of a cocktail of antisense (alphashh/alphatwhh) oligonucleotides reduces expression of both hh genes in the RPE and slows or arrests the progression of rod and cone photoreceptor differentiation. Zebrafish strains known to have mutations in Hh signaling pathway genes similarly exhibit retardation of photoreceptor differentiation. We propose that hedgehog genes may play a role in propagating photoreceptor differentiation across the developing eye of the zebrafish.

Animals↗
PubMed1995

Evaluation of health and ruminal variables during adaptation to grain-based diets in beef cattle.

Health and ruminal variables were intensively measured during adaptation to grain-based diets in 6 beef cattle with fistulated rumens. The cows had been maintained on prairie grass hay-supplemented diets, and were converted to a grain-based finishing ration by feeding each successive diet (diets 1-4, respectively) for a period of 7 days. Each cow was evaluated and samples were obtained 3 times each day for the first 5 days that each diet was fed. Health variables monitored were rectal temperature, pulse, respiratory and rumen motility rates, fecal consistency, demeanor, blood pH, and blood glucose and L (+) lactate concentrations. Ruminal variables monitored were pH and glucose, DL-lactate, and volatile fatty acid concentrations of rumen contents. Data were analyzed by use of a multivariate ANOVA. We determined that most of the health variables were within reference range limits throughout the adaptation period; however, analysis of pulse and respiratory rates indicated that diets 2 and 4 were stressful. Although blood pH continually decreased during feeding of the 4 diets (7.38 to 7.30), blood L (+) lactate and glucose concentrations had large increases only within diet 4. The pH of ruminal contents decreased progressively from 6.8 to 5.3. Rumen glucose concentration was low (< mumol/ml), except with diet 4 in which values were 8 times higher than for other diets. By the end of the study, the ruminal contents of all animals were acidic (pH < 5.5), and, on the basis of higher than background amounts of ruminal glucose and DL-lactate, it was determined that rumen microbial equilibrium had not yet been achieved.(ABSTRACT TRUNCATED AT 250 WORDS)

Acclimatization↗
PubMed1994

[D-penicillamine-induced myasthenia gravis].

D-penicillamine has been used in the treatment of rheumatoid arthritis for years. As a rare complication of this treatment the occurrence of myasthenia gravis has been described, the clinical features of this complication being indistinguishable from that of idiopathic myasthenia gravis. Both D-penicillamine induced and idiopathic myasthenia gravis show elevated titers of acetylcholine receptor antibodies and respond to acetylcholinesterase inhibitor treatment. We report on a patient with rheumatoid arthritis who, under treatment with D-penicillamine, developed severe myasthenia gravis which required temporary acetylcholinesterase inhibitor therapy. 8 months after D-penicillamine was discontinued the acetylcholine receptor antibodies had disappeared and the acetylcholinesterase inhibitors could be withdrawn. Clinical findings and possible pathogenetic aspects of D-penicillamine induced myasthenia gravis are discussed.

Aged↗
PubMed1987

Synovial sarcoma of the jaw in a dog.

A case of synovial sarcoma of the jaw with pulmonary metastasis is described in a dog. It appears to be a rare or underdiagnosed neoplasm in animals and not previously reported in the jaw. Its diagnostic microscopic features are the biphasic cellular pattern and cleft formations. It may otherwise resemble haemangiopericytoma, malignant fibrous histiocytoma, reticulum cell sarcoma, fibrosarcoma, or giant-cell tumour of soft tissue.

Animals↗
PubMed1987

Vitamin E requirements of dairy calves.

Thirty-two Holstein heifer calves receiving conventional rations were supplemented with 0 (control), 125, 250, or 500 IU of vitamin E/calf per d. The objective was to determine the optimum requirement based on their overall performance from birth to 24 wk of age. Overall weight gains at 24 wk were higher with 125 and 250 IU and intermediate with 500 IU supplementation compared with no supplementation. Total dry feed consumption and fecal scores were similar among treatments. Serum alpha-tocopherol increased with increased supplementation in a quadratic fashion, being almost doubled with 125 IU compared with that of control calves. Serum creatine kinase, glutamic oxalacetic transaminase, and lactic dehydrogenase values in the unsupplemented calves indicated cell membrane damage. Serum glucose was higher at 8 wk in supplemented calves, but no differences among other serum metabolites were observed. Hematological responses at 4 and 8 wk of age indicated lower mean corpuscular hemoglobin in calves given 500 IU than others and lower mean corpuscular hemoglobin concentration in calves given 500 IU than in calves given 125 or 250 IU. We conclude that supplementation of conventional rations with 125 to 250 IU vitamin E/animal per d can increase the performance of calves.

Animals↗
PubMed1986

Rumen microbial changes in cattle fed diets with or without salinomycin.

Four rumen-fistulated steers, randomly assigned to two groups (control and salinomycin fed) were used to monitor the changes in rumen microbial populations and volatile fatty acids (VFA) concentrations associated with feeding salinomycin (0.22 mg X kg-1 X day-1). Steers were adapted to an alfalfa hay and grain (80:20) diet before supplementing the diet with salinomycin, and then the diet was changed to 50:50 and 20:80 ratios of alfalfa hay to grain at 2-week intervals. Rumen samples for total and selective enumeration of anaerobic bacteria. VFA analysis, and enumeration of protozoa were collected during the 80:20 alfalfa hay-to-grain diet before salinomycin feeding, and during the 80:20, 50:50, and 20:80 hay-to-grain diets with salinomycin. At each sampling period, rumen samples were collected at 3 h after feeding on three consecutive days. Salinomycin feeding had no effect on rumen pH and total VFA concentration. The acetate-to-propionate ratio was significantly lower in salinomycin-fed steers than in the control. The molar proportion of butyrate increased in both control and salinomycin-fed steers. Total anaerobic bacterial counts were lower in salinomycin-fed steers than in the control steers after 8 weeks of salinomycin feeding. Salinomycin-resistant bacteria increased from 7.6 to 15.6% in salinomycin-fed steers but remained unchanged in control steers. Salinomycin had no effect on cellulolytic and lactate-utilizing bacteria, but the proportion of amylolytic bacteria was higher in salinomycin-fed steers than in control steers. The total number of protozoa decreased initially in salinomycin-fed steers. The initial reduction was due to reduced numbers of Entodinium species. Holotrichs were unaffected by salinomycin feeding.

Animal Feed↗
PubMed1986

Effect of supplemental vitamin E on the immune system of calves.

The effect of vitamin E on immune responses of Holstein calves was investigated. Treatments were: 0,1400, and 2800 mg of dl-alpha-tocopheryl acetate given orally at weekly intervals or 1400 mg of dl-alpha-tocopherol weekly by injection. Calves were fed milk for 6 wk and then fed a complete calf starter ad libitum. Calves were on experiment until they were 12 wk of age. Lymphocyte stimulation indices were significantly higher for calves given the high amount of oral supplementation and for injected calves than for unsupplemented calves. There were no significant differences at any of the individual weeks between unsupplemented and orally supplemented calves. Injected calves showed significantly higher values than unsupplemented calves at wk 4 and than all other calves at wk 8. There were no significant differences in the concentrations of immunoglobulins G1 and G2 among treatments. Immunoglobulin M was significantly higher at wk 6 in calves given the high amount of oral supplementation than in all other calves. At wk 12, serum from calves given the high amount of oral supplementation and calves given injections inhibited infectious bovine rhinotracheitis viral replication in tissue cultures as compared with those of unsupplemented calves. In supplemental experiments serum alpha-tocopherol and lymphocyte stimulation indices of yearling heifers determined 7 d after a single injection of 2000 IU of dl-alpha-tocopherol were significantly higher than preinjection values. In vitro addition of vitamin E to lymphocyte cultures did not increase phytohemagglutinin-induced blastogenesis.

Animals↗
PubMed1986

Blood, urine, and ruminal fluid changes associated with metabolic alkalosis induced by duodenal obstruction.

Two Holstein heifers and a steer fitted with ruminal and duodenal cannulas were used to determine acid-base and electrolyte changes associated with metabolic alkalosis induced by duodenal obstruction. Obstruction was induced distally to the pylorus, but proximally to the common bile duct entrance. Ruminal fluid, blood, and urine samples were obtained before and after obstruction was induced. Duodenal obstruction resulted in increased blood pH, bicarbonate concentration, and base-excess values. Severe hypochloremia and hypokalemia were evident in 48 hours. Serum sodium concentration decreased only slightly. Packed cell volume and serum concentrations of urea nitrogen, creatinine, glucose, and inorganic phosphate increased, whereas calcium concentration showed no change. Renal chloride excretion reached near zero in 24 hours, whereas sodium and potassium excretions decreased in the steer, but were unchanged in the heifers. Urine creatinine concentration increased markedly in the heifers and steers. Acid urine was not evident up to 96 hours. Ruminal fluid pH decreased and chloride concentration increased in the steer, but remained unaffected in the heifers. Duodenal obstruction had no effect on rumen sodium, calcium, and magnesium concentrations, but the potassium concentration increased in the heifers. The degrees of alkalosis and electrolyte changes were greater in the steer than in the heifers.

Alkalosis↗
PubMed1985

Effects of supplemental vitamin E on the performance and metabolic profiles of dairy calves.

Twenty-eight Holstein heifer calves were allotted at birth to one of four treatments: 1) 0 mg, 2) 1,400 mg, or 3) 2,800 mg of dl-alpha-tocopherol acetate given orally at weekly intervals, or 4) 1,400 IU of dl-alpha-tocopherol weekly by intramuscular injection in order for us to study their performance and metabolic profile. Calves were fed milk at 8% of birth weight until they were weaned at 6 wk of age and fed a complete calf starter ad libitum from birth. Calves were on experiment for 12 wk. There were no significant differences in weekly weight gains, starter consumption, and fecal scores among treatments. However, there was a trend toward greater starter consumption and weight gains in supplemental calves. Serum alpha-tocopherol concentration measured after 7 d of each administration was significantly higher at wk 4 in calves given the high oral supplementation and at wk 2, 4, 6, and 8 higher in injected calves than in unsupplemented calves. Creatine kinase activity was higher in unsupplemented calves and negatively correlated with serum alpha-tocopherol until wk 8, suggesting preclinical muscular dystrophy. Alkaline phosphatase activity was higher with the high oral supplementation. Serum carbon dioxide values showed a trend toward positive correlation with those for serum tocopherol; however, the values were within normal range. There were no significant differences in creatinine, glucose, phosphorus, calcium, urea nitrogen, chloride, sodium, potassium, albumin, and total protein among treatments. Serum glucose was higher in all calves at wk 10 and 12 than at wk 4, 6, and 8. Calves may not get enough vitamin E with conventional calf starters, and supplementation may be essential to obtain maximum performance.

Administration, Oral↗
PubMed1984

Effect of dietary niacin supplementation on phlorhizin and 1,3-butanediol-induced ketonemia and hypoglycemia in steers.

1,3-Butanediol and phlorhizin were used to induce ketonemia and hypoglycemia in steers. Oral administration of butanediol increased blood beta-hydroxybutyrate (BHB) and plasma nonesterified fatty acids (NEFA) and decreased serum glucose. Subcutaneous injections of phlorhizin, given in addition to butanediol orally, further increased NEFA and BHB concentrations and decreased glucose. Dietary niacin supplementation of steers given phlorhizin and butanediol caused serum glucose concentration to increase and blood BHB and plasma NEFA concentrations to decrease.

3-Hydroxybutyric Acid↗
PubMed1984

Effect of dietary niacin supplementation on serum constituents of periparturient dairy cattle.

A total of 60 multiparous periparturient Holstein cows were used to determine the differences in serum constituents between cows given supplemental niacin in the diet and cows not given supplemental niacin. Serum inorganic phosphorus concentration was consistently higher (P less than 0.10) and serum potassium, total calcium, and sodium concentrations and alkaline phosphatase activities were consistently lower in cows given supplemental niacin than in cows not given supplemental niacin. Serum chloride, creatinine, and albumin values also tended to be lower in niacin-supplemented cows. Serum total protein tended to be slightly higher in niacin-supplemented cows. There was no consistent difference in urea nitrogen between groups of cows.

Alkaline Phosphatase↗
PubMed1975

Hypervitaminosis A in the dog.

Toxic effects of excessive vitamin A and of excessive vitamin ADE were studied in 9 mixed Labrador Retriever pups. Clinical signs were loss of body weight, dullness, emaciation, roughened coat, evident pain in limb joints, and retarded growth. Radiologic changes were decreases in overall length and thickness of long bones, development of osteophytes, periosteal reaction, and premature closure of epiphyses. Pathologic changes were degenerative epiphyseal plate, hemorrhage and exostotic proliferation of periosteum, fatty liver, and microcalculi in kidney. Toxic effects of excessive vitamin A did not appear to be so great when it was administered as vitamin ADE.

Animals↗
PubMedDate not supplied

An inexpensive variable-frequency microwave system for hyperthermia.

A microwave hyperthermia system is described which uses surplus communications equipment. The most costly components of the microwave system, the signal generator and amplifier, were obtained through the Federal Surplus Supply System. The cost of the entire system, including 2450 MHz applicator and temperature monitoring system, is under $1200. Extensive testing has demonstrated the capability of heating several cm3 mouse tumors to a temperature of 42.5 degrees C. Depth of heating can be varied by adjusting the frequency of the oscillator or by adjusting the output attenuator.

Animals↗