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Biomedical subjects

M H Elissalde

Publications and source records attributed to M H Elissalde.

51 records · Page 3Linked to original sources
PubMed1980

The role of prostaglandin F2 alpha in byssinosis.

Female guinea pigs were perfused via the pulmonary artery with Tyrode's solution containing 0, 10(-6), 10(-5), or 10(-4) g/mL of lyophilized aqueous extracts of cotton dust. The perfusate was collected via the pulmonary vein and analyzed for prostaglandin F2 alpha, its metabolite 15-keto-13, 14-dihydro-prostaglandin F2 alpha and histamine. The histamine content of the pulmonary parenchyma was also analyzed. Prostaglandin F2 alpha, its metabolite, and the percentage of total histamine released increased in a dose related fashion and were significantly higher in the perfusate of the animals which had received the two highest doses than that of the controls. Since prostaglandin F2 alpha can increase airway resistance and bronchial smooth muscle contraction and decrease pulmonary tidal volume, its liberation into the respiratory system could play a role, along with histamine, in the acute bronchial constriction that follows the inhalation of cotton, flax, or hemp dust.

Animals↗
PubMed1980

Hematologic study of effects of levamisole on stressed cattle.

The effects of shipping stress, increased serum cortisol concentrations, and levamisole treatment on the hematologic values of cattle were studied. Complete blood counts were done on blood samples from 40 calves; samples were collected 9 times during a period that began immediately after the calves were weaned and continued through an auction barn-truck transport cycle plus 5 weeks. The object of the study was to determine whether the combination of shipping stress and levamisole treatment would alter the hematologic values (granulocytic series). There was no effect observed.

Animals↗
PubMed1979

The role of cyclic AMP and cyclic GMP in byssinosis.

The lungs of female guinea pigs, either untreated or previously sensitized with aqueous extracts of cotton dust (AECD) were perfused via the pulmonary artery with 0, 10-6, 10-5 or 10-4 g/mL of lyophilized AECD in Tyrodes solution. Pressure changes in the pulmonary artery were monitored during this period. After perfusion, the pulmonary parenchyma was excised, frozen, and later analyzed for c-AMP, c-GMP, histamine, and total protein. Levels of c-AMP and histamine decreased while levels of c-GMP and pulmonary arterial pressure increased with increasing doses of AECD. Correlation coefficients, between the parameters measured, indicate that the ratio of c-AMP to c-GMP (c-AMP/c-GMP) was a better indicator of histamine depletion or change in pulmonary arterial pressure than was the level of either c-AMP or c-GMP alone. Comparisons of the relative changes in c-AMP, c-GMP, c-AMP/c-GMP, histamine, and pulmonary arterial pressure between sensitized and nonsensitized guinea pigs support the hypothesis that the acute changes in pulmonary function that follow breathing of cotton dust are due to the effects of pharmacoactive compounds and not to antigen-antibody response.

Animals↗
PubMed1979

Abortion in laboratory animals induced by Moraxella bovis.

Pregnant mice, guinea pigs, rats, and rabbits responded to injections of Moraxella bovis strain EPP-63(300) with abortion, death, embryo resorption, and production of small litters. The nature of response appeared to depend primarily on the number of viable cells injected and to some extent on the species of animal and stage of pregnancy. Intraperitoneal injection of mice with 3 X 10(5) viable cells induced 100% abortion and no deaths. Embryo resorption and smaller litters were induced with injection of lower doses of M. bovis. None of the rats used in this study aborted; however, resorption rates were higher in rats than mice. Bacteria-free filtrates prepared from aqueous extracts of blood agar on which M. bovis had been grown induced abortion in mice and guinea pigs, at a rate similar to that caused by viable cells. The lyophilized filtrate could be diluted to produce 100% abortion with no death of injected mice. Abortion-inducing, nonlethal doses of M. bovis and lyophilized filtrates appeared to have no effect on nonpregnant female or male mice.

Abortion, Spontaneous↗
PubMed1979

Combinative effects of hexachlorobenzene and crowding on rat adrenal cell mitochondria.

The effects of social stress (crowding) on hexachlorobenzene (HCB) toxicity in male rats was evaluated by a morphometrical analysis of adrenal cortex mitochondria. The social stress was produced by transferring singly-housed rats from cages of ample size (1000 cm2 floor space) into small cages (100 cm2 floor space) each containing four rats. Differences in cage design as well as size may have contributed to the overall stress experienced by the rats. The food of the treated rats was supplemented with 250 ppm HCB. Structural changes in mitochondrial volume, surface area, or cristae area were not significant in HCB-treated or in crowded animals when compared with those of the controls. However, increases in mitochondrial volume and diameter were significant in those animals simultaneously challenged by HCB and crowding. The results strongly suggest that even a relatively mild social stress may adversely affect the ability of an animal to resist the effects of some exogenous chemicals.

Adrenal Cortex↗
PubMed1979

Testosterone metabolism by hexachlorobenzene-induced hepatic microsomal enzymes.

Hexachlorobenzene, which is a widespread contaminant of meat and meat animal by-products throughout the world, had a profound effect on the homeostatic mechanism which controls the serum testosterone concentrations in the mouse. Significant increases in the mean hepatic weight, the concentrations of hepatic microsomal protein, cytochrome P-450, cytochrome b5, and cytochrome c reductase activity occurred in the aminals given a ration containing 250 mg of hexachlorobenzene/kg for 21 days, when compared with their nontreated controls. These increases in cytochrome concentrations and enzyme activity of the hepatic microsomes are reflected by significant increases in the in vitro metabolism of [3H]testosterone and a decrease in the serum concentrations of testosterone with a concomitant decrease in the weights of the seminal vesicles and ventral prostate of the mouse.

Animals↗
PubMed1977

Technique for sampling subcutaneous fat from the tailhead of sheep.

Previously reported fat biopsy techniques (either omental or subcutaneous) require extensive restraint of the animal, require anesthesia methods, are time-consuming to do, or demand much postoperative care. The biopsy technique reported in the present paper involves the subcutaneous fat located around the tailhead of sheep. With minimal restraint of the sheep and local anesthesia, up to 1 g of subcutaneous fat can be obtained using this surgical procedure. Michel clips facilitate closure of the surgical wound, making this method brief in operative time.

Adipose Tissue↗
PubMedDate not supplied

Interaction of environmental stress and hexachlorobenzene in the laboratory rat.

The effects of hexachlorobenzene (HCB) on the ability of male rats to adapt to a crowded environment were investigated. Eighty male rats were individually housed (1000 cm2 floor space per rat) and given either feed containing 250 ppm HCB or control feed. After 4 w, half of the rats from each diet group were transferred to smaller cages with four rats per cage (100 cm2 floor space per rat). After 1, 2, 4, 7, and 10 d, four rats each from the four treatment groups were sacrificed and organs removed for analysis. The HCB diet alone had no effect on the body weight of the rats. Crowding resulted in severe loss of body weight, an effect that was potentiated by the HCB diet. The HCB diet resulted in increased liver and kidney weight but had no effect on brain weight. Livers and kidneys of crowded rats weighed less than those of singly housed rats. Rats fed HCB then crowded had higher tissue residues of HCB and higher mortality than rats given HCB and not crowded or rats crowded but not given HCB.

Animals↗
PubMedDate not supplied

Changes in hematological, blood gas, and serum biochemical variables in broilers during exposure to simulated high altitude.

One-day-old broilers were reared until 35 days of age at both natural low (100 m) and simulated high altitude (2133 m) to assess the incidence and development of ascites syndrome. Clinical measurements were conducted at 7, 14, 21, 28, and 35 days of age. Birds reared at 2133 meters exhibited significantly (P less than or equal to 0.05) reduced body weights at 7 through 28 days of age. Total serum calcium and biochemical enzyme activities were found to be altered at 35 days of age. In addition, the high-altitude group had significantly (P less than or equal to 0.05) higher erythrocyte counts, hematocrits, and hemoglobin at 14, 21, 28, and 35 days of age and higher serum inorganic phosphorus at each weekly sample time than birds at the low altitude. Total mortality was 20.3% at 2133 meters and 4.6% at 100 meters. The incidence of ascites syndrome in the high-altitude group ranged from 16.6% to 61.1% during the 5-week experimental period.

Altitude↗
PubMedDate not supplied

Effect of immunosuppression with cyclophosphamide, cyclosporin, or dexamethasone on Salmonella colonization of broiler chicks.

One-day-old broiler chicks were divided into four groups: untreated controls and three groups treated with the immunosuppressive drugs cyclophosphamide, cyclosporin, or dexamethasone on days 1-4 of age. On day 5, all groups were challenged orally with 10(4) Salmonella typhimurium. Suppression of immunocompetency was demonstrated in the treatment groups by significant decrease (P less than 0.05) in weights of bursas of Fabricius, and diminished mitogen-induced T and B lymphocyte blastogenesis and cutaneous basophil hypersensitivity responses. There were no significant differences among the four groups in the number of Salmonella in the cecal contents or in the number of cecal-culture-positive chicks on day 10 post-challenge at 15 days of age. Results indicated that impairment of B or T lymphocyte responses had little influence on the resistance of young chicks to Salmonella cecal colonization.

Animals↗
PubMedDate not supplied

Intracloacal Salmonella typhimurium infection of broiler chickens: reduction of colonization with anaerobic organisms and dietary lactose.

The combined effect of treatments with dietary lactose plus anaerobic organisms on cecal colonization of broiler chicks by Salmonella typhimurium was evaluated. Chickens treated with a combination of anaerobic organisms and 7% dietary lactose were resistant to cecal colonization by S. typhimurium. The number of recoverable S. typhimurium cells per gram of cecal contents taken on days 10 and 15 after infection was significantly reduced. Treatment with anaerobes without the addition of lactose did not effectively control cecal colonization. Intracloacal inoculations with bacterial concentrations that varied by 10,000-fold resulted in roughly similar levels of colonization. The treatments resulted in reduced cecal pH and elevated levels of undissociated volatile fatty acids. Statistically significant correlations (P less than 0.01) were observed between the S. typhimurium concentrations in cecal material and the concentrations of undissociated fatty acids (r = -0.79, and between the bacterial counts and pH (r = 0.72).

Animals↗
PubMedDate not supplied

Efficacy of zeolitic ore compounds on the toxicity of aflatoxin to growing broiler chickens.

Commercially available zeolitic ore compounds, when incorporated into the diets at 0.5%, were evaluated for their ability to reduce the deleterious effects of 3.5 mg aflatoxin/kg feed on growing broiler chickens from 1 day to 3 weeks of age. In a series of four experiments, the compounds used included the following: mordenite (particle size of -20 mesh; Zeomite); clinoptilolite (particle size of -20 mesh; Zeobrite); SC Zeolite (particle size of -20 mesh); and clinoptilolite (particle size of -35 mesh; Clino 1) or clinoptilolite (particle sizes of -20 plus +35 mesh; Clino 2). Results demonstrated that 0.5% Zeobrite, Clino 1, or Clino 2 added to aflatoxin-contaminated diets did not significantly (P < 0.05) diminish the toxicity of high concentrations of aflatoxin to growing broiler chicks. Zeomite mordenite ore reduced the toxicity of aflatoxin to growing chicks by 41%, as indicated by weight gains, liver weight, and serum biochemical measurements, which compares favorably with its in vitro binding capacity to aflatoxin. SC Zeolite reduced weight-gain toxicity of aflatoxin by approximately 29%.

Adsorption↗