PubMed Health⌕ Search

Biomedical subjects

J K Porter

Publications and source records attributed to J K Porter.

At least 37 records · Page 2Linked to original sources
PubMed1988

Neurochemical effects of cyclopiazonic acid in chickens.

Chickens dosed (per os) with cyclopiazonic acid (CPA) at 0.5, 5.0, and 10 mg/kg body weight showed significant (P less than or equal to 0.05) increases in brain dopamine and serotonin concentrations 96 hr after dosing. The increases coincide with significant decreases in homovanillic acid and subtle increases of dihydroxyphenylacetic acid and 5-hydroxyindoleacetic acid concentrations. The elevated dihydroxyphenylacetic acid and 5-hydroxyindoleacetic acid concentrations may be related to the elevated concentrations of dopamine and serotonin, respectively. The observed changes in neurotransmitter/metabolite concentrations 96 hr after dosing parallel elimination of CPA from the birds skeletal muscles; however, they do not correlate with the significant weight losses in these birds at 48 and 96 hr after dosing. The brain weights of the treated birds were statistically insignificant from their respective controls, although increases in brain weight-body weight ratio within treatments and with time correlated with CPA toxicity. No significant changes were observed in dopamine, dihydroxyphenylacetic acid, homovanillic acid, serotonin, and 5-hydroxyindoleacetic acid concentrations among the treatments at 3, 24, and/or 48 hr after dosing.

Animals↗
PubMed1987

Quipazine-metoclopramide inhibition of CB-154-induced prolactin suppression in rats: neurotransmitter-metabolite correlations.

The ability of quipazine and metoclopramide to protect rats from CB-154-induced suppression of serum prolactin concentrations was studied. These drugs affect whole brain concentrations of dopamine and serotonin, and their major metabolites dihydroxyphenylacetic acid, homovanillic acid, and 5-hydroxyindoleacetic acid. Serum prolactin concentrations have been correlated with the concentrations of the neurotransmitters and their respective metabolites. Differences in the metabolite/precursor ratios have been used to compare turnover rates of the neurotransmitters dopamine and serotonin. Increased turnover of dopamine and decreased turnover of serotonin correlate with elevated prolactin concentrations for quipazine and metoclopramide administered together. The combination of quipazine and metoclopramide protects rats against CB-154-induced prolactin suppression better than either of the drugs given alone. This study suggests that a quipazine-metoclopramide regimen may have therapeutic potential for combating ergotlike fescue and other similar toxicities observed in cattle grazing on endophyte-infected pasture grasses.

Animals↗
PubMed1986

Open window thoracostomy and plastic surgery with muscle flaps in the treatment of chronic empyema.

Open window thoracostomy (OWT) and plastic surgery using myocutaneous flaps of extrathoracic muscles, was done in nine patients with chronic empyema, after conventional therapy had failed. In all these patients, the pleural cavity and bronchopleural fistulas, when present, closed within eight to 61 days (mean 30), after the second stage of surgery comprising the myoplasty; this in turn was performed between three to seven (mean 3.0) months after the OWT. All patients were considered cured with a minimal deformity of the chest wall. The final scar had an acceptable cosmetic appearance.

Adolescent↗
PubMed1982

Bacterial bioluminescence as a bioassay for mycotoxins.

The use of bacterial bioluminescence as a toxicological assay for mycotoxins was tested with rubratoxin B, zearalenone, penicillic acid, citrinin, ochratoxin A, PR-toxin, aflatoxin B1, and patulin. The concentrations of mycotoxins causing 50% light reduction (EC50) in Photobacterium phosphoreum were determined immediately and at 5 h after reconstitution of the bacteria from a freeze-dried state. Generally, less toxins were required to obtain an EC50 at 5 h. The effects of the above mycotoxins on bioluminescence were determined after 5, 10, 15, and 20 min of incubation with the bacterial suspensions. The concentration of rubratoxin B necessary to elicit an EC50 increased with time, whereas the concentration of citrinin, penicillic acid, patulin, and PR-toxin necessary decreased with time. There was very little change in the concentration of zearalenone, aflatoxin B1, and ochratoxin A required to elicit an EC50 with time. The bacterial bioluminescence assay was most sensitive to patulin and least sensitive to rubratoxin B.

Biological Assay↗
PubMed1982

Use of drugs during cardiopulmonary resuscitation: a review of the literature.

The use of drugs during cardiopulmonary resuscitation is often a crucial factor in saving the lives of patients suffering cardiac arrest. However, inappropriate use of these agents may produce deleterious effects that may increase morbidity and adversely affect the outcome of resuscitative measures. It is imperative to realize that cardiac arrest is a frank disease entity with very specific signs and symptoms deserving specific and precise treatment.

Anti-Arrhythmia Agents↗
PubMed1979

Laboratory production of ergot alkaloids by species of balansia.

Four species of Balansia (clavicipitaceous systemic grass pathogens) isolated from pastures where cattle showed signs of ergot toxicity were grown in culture. Balansia epichloë, one isolate of B. claviceps, B. henningsiana and two isolates of B. strangulans produced conidia in submerged culture during the first stage of a two-stage fermentation procedure. When tranferred to a glucose/sorbitol/inorganic salts medium during the second stage, these four species produced ergot alkaloids in stationary cultures. The transfer of fungi cultured in the first medium to the second medium was necessary for alkaloid biosynthesis. One isolate of B. claviceps did not produce alkaloids. Balansia epichloë produced chanoclavine (I), agroclavine, penniclavine, elymoclavine, ergonovine and ergonovinine. Balansia claviceps produced chanoclavine (I), ergonovine and ergonovinine. This is the first report of isolating ergonovine and ergonovinine, two lysergic acid derivatives, from fungi outside the genus Claviceps. Only chanoclavine (I) was identified from extracts of B. strangulans and B. henningsiana. Chanoclavine (I) and ergonovine were identified from smut grass (Sporobolus poiretii) parasitized by B. epichloë, indicating that this endophyte produces alkaloids both in vivo and in vitro.

Ascomycota↗
PubMed1977

Media for identification of Gibberella zeae and production of F-2-(Zearalenone).

Media are described for the isolaton of Fusarium graminearum in the perithecial state, Gibberella zeae, and for the production of F-2 (zearalenone) by Fusarium species. On soil extract-corn meal agar isolated medium, G. Zeae produced perithecia in 9 to 14 days under a 12-h photoperiod. Species of Fusarium were screened for F-2 production on a liquid medium. From strains that produced F-2, the yields, from stationary cultures of G. zeae and F. culmorum after 12 days of incubation, ranged from 22 to 86 mg/liter. Three strains produced no F-2. Glumatic acid, starch, yeast extract,and the proper ratio of medium volume-to-flask volume were necessary for F-2 synthesis.

Culture Media↗
PubMed1977

Epichloë typhina from toxic tall fescue grasses.

Epichloë typhina, a clavicipitaceous systemic phytopathogen, was isolated from two varieties and three hybrids of tall fescue (Festuca arundinaceae). The morphology of the fescue isolates was compared with E. typhina isolated from bent grass (Agrostis perennans). In all isolates, conidia were identical and were typical of E. typhina. In fescue grasses the endophyte failed to produce stromata, but on bent grass the fungus seasonally produced stromata, typical of the genus. Cattle grazing the fescue grasses showed signs of the fescue toxicity syndrome, the E. typhina was found in frequencies of 100%; in grasses from pastures in which cattle showed no signs of the syndrome, frequencies were 0 to 50%. Nutritional factors in vitro were more complex for the isolates from fescue than for the isolate from bent grass. These studies suggested that E. typhina includes biotypes that might be involved in the toxicity syndrome. The fescue biotypes grew poorly on media, and yields were inadequate for toxicity studies. However, the bent grass isolate grew well on three media, and extracts from two of these were toxic to chicken embryos. All isolates produced in vitro the nontoxic fungal steroid tetraenone [ergosta-4,6,8(14),22-tetraen-3-one], which has been isolated from toxic fescue grasses.

Animals↗
PubMed1975

Toxicity and occurrence of Balansia on grasses from toxic fescue pastures.

Balansia epichloe (Weese) and B. henningsiana (Moell.) were isolated from grasses in toxic fescue pastures. B. epichole, cultured in a synthetic medium, was toxic to chicken embryos. Thin-layer chromatography and ultraviolet absorption data indicated that in submerged culture the fungus produced compounds with the indole or ergoline nucleus.

Animals↗
PubMedDate not supplied

[Bioethics panorama in Mexico].

Ethical values and principles are singular and immutable, but this is not true of their interpretation and application. In Mexico, even though these values and principles are respected in medical practice, the teaching of bioethics is non-existent and in most of the schools for health professionals the subject is not included in the curriculum. Nevertheless, Mexican society has made notable progress in the legislation and regulation of ethical aspects of such activities as research on human subjects, fertility regulation, the right to death with dignity, organ transplants, and AIDS.

Acquired Immunodeficiency Syndrome↗