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Biomedical subjects

J Ward

Publications and source records attributed to J Ward.

At least 343 records · Page 19Linked to original sources
PubMed1980

Respiratory oscillations in arterial carbon dioxide tension as a control signal in exercise.

We have monitored oscillations in arterial pH (of respiratory frequency) in normal man at rest and during exercise. The pH oscillations are known to reflect respiratory oscillations in arterial carbon dioxide tension generated at the lungs. We have found that the pH oscillations increase in their upslope and downslope during exercise. This means that oscillations in arterial carbon dioxide tension can be considered as a control signal.

Carbon Dioxide↗
PubMed1980

Comparative effect of intravenous dipyridamole and sublingual nitroglycerin on coronary hemodynamics and myocardial metabolism at rest and during atrial pacing in patients with coronary artery disease.

The effects of intravenous dipyridamole (20 mg) and sublingual nitroglycerin (0.6 mg) were compared at rest and during rapid atrial pacing in patients with significant coronary obstruction. Dipyridamole, which had no significant effect on resting systolic blood pressure, caused a significant increase in coronary sinus flow (CSF) and reduction of coronary vascular resistance (CVR) and arterial-coronary sinus oxygen difference (AO2CSO2 delta), whereas nitroglycerin reduced resting systolic pressure but had no significant effect on CSF, CVR, or AO2-CSO2 delta. Although theses effects of dipyridamole and nitroglycerin on resting systolic pressure, CSF, CVR, and AO2-CSO2 delta were qualitatively similar during rapid atrial pacing, the onset of chest pain and ischemic ECG changes occurred at a lower heart rate following dipyridamole (136 +/- 5 beats/min) than following nitroglycerin (149 +/- 6 beats/min, p less than 0.01). However, maximal double product and myocardial oxygen consumption achieved during pacing were similar following both dipyridamole and nitroglycerin and were less than control pacing values. Coronary dilatation following dipyridamole appears to reduce tolerance to pacing-induced ischemia probably by maldistribution of coronary flow away from ischemic myocardium. Nitroglycerin differs from dipyridamole by improving tolerance to pacing; however, this difference appears to be due to systemic vasodilator effects of nitroglycerin rather than to enhancement of flow to ischemic myocardium.

Aged↗
PubMed1980

Synchronous combined transvaginal-transvesical repair of vesicovaginal fistulas.

Nine cases of vesicovaginal fistula which followed hysterectomy, with or without radiotherapy, are presented. The repair by the above-mentioned technique eventually led to successful closure in all cases. A strong argument can now be advanced that this is the technique of choice in the large, high postoperative type of vesicovaginal fistula which is now the common type of fistula seen in affluent countries.

Female↗
PubMed1980

Effects of modification of conceptual tempo on acquisition of work skills.

This study investigated the effects of modification of conceptual tempo on the skilled performance of a group of mildly intellectually handicapped adolescents receiving training in a work preparation centre (N, 41). On the basis of performance on Kagan's Matching Familiar Figures Test the group was divided into two subgroups, reflective, impulsive and then further divided through random allocation to control and experimental conditions. The two experimental groups received a training program designed to promote self-generation of strategies, using self-verbalization to induce a more reflective approach. The control groups received the normal training program of the centre. The criterion measure taken at pre- and posttest was a collation task standardized so as to provoke response uncertainty. Analysis of residual gain scores derived from the two testing occasions indicated that the experimental groups improved significantly more than the controls and that the improvement generalized to their performance on the Porteus Maze and Matching Familiar Figures Test. Contrary to expectation, however, the effect of training did not bring about significant differential improvement for impulsive as against reflective subjects. Both benefited from the training. On the basis of delayed posttests, no generalization was apparent.

Adolescent↗
PubMed1979

Deficits in fixed-interval performance following prenatal and postnatal lead exposure.

Female rats were exposed daily to 750 mg/kg of lead acetate via a restricted watering schedule for 70-80 days prior to mating and then throughout pregnancy and nursing. At weaning, litters from half of the lead dams were placed directly on treatment for the duration of the experiment. These manipulations yielded 3 groups: Group Pb/Pb, offspring exposed during pre- and postweaning periods; Group Pb/C, offspring exposed only during preweaning periods: and Group C/C, control offspring. Beginning at 42-49 days of age, postnatal, offspring were shaped to bar press under a fixed-interval, 1-min schedule (FI1) and then given 20 sessions, each 45 min in length. Analyses revealed that Group Pb/Pb received fewere reinforcements across sessions than the other 2 groups, which did not differ. However, when the Pb/Pb offspring did receive reinforcement, they exhibited the scalloped pattern of responding characteristic of fixed-interval schedules.

Animals↗
PubMed1979

The intracellular survival and growth of gonococci in human phagocytes.

In reassessment of previous tests for intracellular survival, results have been confirmed and additional evidence obtained indicating that some gonococci can survive and multiply in human phagocytes. Use was made of the ability of penicillin to penetrate phagocytes and to kill only actively growing organisms. In microscopic counts on 33 urethral exudate smears, an average of 49% of gonococci were associated with polymorphonuclear phagocytes. The organisms were unevenly distributed amongst the phagocytes, with most cells uninfected and some containing large numbers. Many phagocytes also remained uninfected in tests in vitro with low gonococcal inocula although experiments with large inocula showed that most phagocytes could ingest gonococci. It is proposed that ingestion of one gonococcus may stimulate the phagocytes to take up more. Phagocytes were killed and disintegrated after ingesting large numbers of gonococci and similar effect in vivo may be responsible for the large clumps of organisms seen in urethral exudate. These results underline the probable importance in the pathogenesis of gonorrhoea of intracellular survival in phagocytes.

Blood Bactericidal Activity↗
PubMed1979

Responses of pony mares to the agent of contagious equine metritis 1977.

Reproduction of contagious equine metritis 1977 in Pony mares was achieved with cultures of an unclassified Gram-negative coccobacillus. Infected mares developed a vaginal discharge and associated inflammatory changes of the cervix and vagina. There was evidence of variation in pathogenicity between different strains of the organism. Although all infected mares made spontaneous clinical recoveries, the Gram-negative coccobacillus persisted in the genital tracts of a considerable proportion for a variable period after challenge. Recovery of the organism was not associated solely with the occurrence of oestrus. None of the mares has carried over infection into the following breeding season. There was no evidence of localization of the organism in the urinary tract. Cytological examination of smears of cervical and urethral swabs was of diagnostic value only during the clinical phase of the infection. A serological response was demonstrable in all mares that became infected after exposure to the Gram-negative coccobacillus. The complement-fixation test gave more specific and clear-cut results than either the agglutination or the antiglobulin test, with which there was a problem with non-specific reactions. The experimental findings indicate the value of the complement-fixation test for confirming recent cases of contagious equine metritis in the mare.

Animals↗
PubMed1979

Offspring open field performance following maternal lead exposure: a question of dosage and nutritional status.

Although a number of experiments has revealed offspring hyperactivity following maternal lead (Pb) exposure, a consistent correlate has been reduced pup size. The present study was designed to measure exploratory behavior employing a range of Pb dosages that allowed for the comparison between Pb and control offspring both in the presence and the absence of weight differences. Female rats were exposed to one of four dosages (0, 400, 750 or 1000 mg/kg) of Pb acetate from 21--90 days of age, mated and then continued on treatment throughout gestation and nursing. Treatment was administered via a restricted water schedule. Open field testing began on Day 22 with the pups receiving 3 min trials for 10 consecutive nights. At 120 days of age, all pups were retested. Analysis indicated that only in the presence of reduced birth and/or weaning weights (Groups 750 and 1000) did offspring exhibit exploratory patterns that were significantly different from controls. These differences were absent at retest.

Animals↗