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Biomedical subjects

P T Doyle

Publications and source records attributed to P T Doyle.

54 records · Page 3Linked to original sources
PubMed1980

Sulfur and methionine metabolism in sheep. IV. Metabolism and absorption in the intestines.

Twelve 18-month-old Merino wethers were fed a ground and pelleted diet of equal parts oaten chaff and lucerne chaff. Sulfur flows at the ileum and faecal excretion of sulfur were estimated for two levels of dry matter intake (500 and 1000 g/day) in sheep receiving intraruminal infusions of water or 4.5 g DL-methionine per day. Increasing dry matter intake from 500 to 1000 g/day resulted in greater flows of total sulfur from 660 to 1183 mg/day in the ileum; protein sulfate increased correspondingly from 312 to 585 mg and non-protein organic sulfur rose from 324 to 497 mg; DL-methionine infusions had no effect. The 1000-g level of intake increased the excretion of all faecal sulfur components compared to those of sheep receiving 500 g dry matter; the amino acid supplement increased total, neutral and total reducible sulfur excretion only at the 500-g level of dry matter intake. The apparent digestibility of sulfur in the small intestine ranged from 36 to 44%, while apparent digestibility between the proximal duodenum and anus ranged from 59 to 66%. Most of this digestion was due to a reduction in organic sulfur in digesta during flow through the intestines.

Animals↗
PubMed1980

Toxic effects of large amounts of DL-methionine infused into the rumen of sheep.

Four Merino wethers were fed ad libitum on a roughage diet comprised of equal parts of chopped lucerne hay and oaten chaff. The sheep received continuous infusions of DL-methionine into the rumen; the daily dose increasing from 0 g (control treatment) up to 30 g in 3 g amounts at weekly intervals. Dry matter intake (DMI) fell below the control level when 24 g/day or more of the amino acid was infused, while plasma free methionine levels increase substantially when 30 g/day was given. There was no effect of DL-methionine supplementation on the bodyweight of the animals. However, when 30 g/day of DL-methionine was infused one animal died and the acute condition of 2 others necessitated their slaughter. Significant lesions included acute nephrosis and haemolytic anaemia, with milder changes in the liver and pancreas. This report indicates that sheep are unlikely to show the kind of chronic methionine toxicity seen in other species.

Amino Acids↗
PubMed1979

Sulfur and methionine metabolism in sheep. I. First approximations of sulfur pools in and sulfur flows from the reticulo-rumen.

Sulfur pools in the rumen and sulfur flows from the rumen were investigated in two experiments with sheep on a diet containing equal parts of oaten and lucerne chaffs. The diet was fed at two levels, either chopped or pelleted, and with intraruminal DL-methionine supplements. Ruminal fluid volumes and fluid flows to the omasum were measured. None of the treatments influenced ruminal fluid volume. Fluid flow to the omasum, however, was increased by increasing dry matter intake (DMI), and was further enhanced by feeding chaffed hay rather than the same materials ground and pelleted; the DL-methionine supplement had no effect. First approximation of the ruminal sulfur pools and of sulfur flows to the omasum were derived from the concentration of sulfur in true digesta and the ruminal fluid volume or fluid flow. Increasing DMI from 500 to 1000 g/day resulted in larger ruminal pools of total (1096 v. 792 mg), neutral (1016 v. 731 mg) and protein (479 v. 419 mg) sulfur, but the reducible sulfur pools were not affected by the level of DMI. Infusions of DL-methionine increased the ruminal sulfide sulfur pool irrespective of level of DMI. The first approximation of total sulfur flow was increased by 1660 mg/day at the higher level of DMI, due mainly to increases of 710 mg S/day as protein sulfur and 859 mg S/day as non-protein neutral sulfur. Flows of inorganic sulfate and ester sulfate sulfur, although small in comparison with organic sulfur flows, increased with level of DMI. Sulfide sulfur flows were also increased at the higher level of DMI, and were almost doubled by intraruminal infusions of DL-methionine.

Animal Feed↗
PubMed1979

Sulfur and methionine metabolism in sheep. II. Quantitative estimates of sulfur metabolism in the sheep's stomach.

The metabolism of dietary and supplemental DL-methionine sulfur in the stomach of sheep was studied in two experiments. In both experiments sheep were fed a 50 : 50 oaten chaff: lucerne chaff ration at two levels of intake, and some animals received intraruminal infusions of DL-methionine. In experiment 2 increasing dry matter intake (DMI) increased first approximations of total, neutral, protein and reducible sulfur flows and also sulfide sulfur flow from the reticulo-rumen. Increased DMI (from 500 to 1000 g/day) also resulted in greater true flows of total (2207 v. 1104 mg/day), neutral (1867 v. 1043 mg/day) and protein (893 v. 482 mg/day) sulfur at the duodenum. Two flow diagrams of sulfur metabolism in the compartments of the ruminant stomach were developed from the data of experiment 2. Fluid flows of sulfur in experiment 1 were used to supplement the data of experiment 2 in developing the balance models. The two models represent the extremes of dietary and supplemental sulfur metabolism in the sheep's stomach under the conditions of experiment 2, and they are discussed in relation to previous research on sulfur metabolism in the stomach.

Animals↗
PubMed1977

Abacterial cystitis.

5 young male patients with all the symptoms and signs of genito-urinary tuberculosis but in whom no organism could be cultured from the urine are described. 4 of them rapidly responded to a course of tetracycline. Various organisms are suggested as a cause of this condition, and careful bacteriological investigation in the future might discover the cause.

Acute Disease↗
PubMed1976

The effects of drugs and anaesthetic agents on the urinary bladder and sphincters.

The influence of sedative, anaesthetic and neuromuscular blocking drugs on diagnostic urethral pressure profiles and cystometrograms has been investigated. These agents have marked effects on the results obtained; in particular, the urethral pressure profile was raised by opiates and lowered by anaesthetic induction agents. Bladder capacity as measured by the cystometrogram was greatly increased by halothane. These findings indicate that urodynamic studies should be performed only on conscious unsedated patients.

Anesthetics↗
PubMed1975

Electromyography of the detrusor muscle.

In order to diagnose and treat patients with micturitional disturbances it is necessary to obtain as much information as possible about the function of the lower urinary tract in each case. We studied 70 female patients with micturitional disturbances by monitoring pulse, respiration, intrinsic bladder pressure, urine flow rate and volume, and detrusor and sphincter electromyograms during a 2 to 4-hour period. As earlier investigators have shown, there are 2 types of detrusor electromyograms: low frequency and high frequency activity. The low frequency activity is random in nature and has definite patterns in disturbed bladder function. It is a useful diagnostic parameter and, when considered with the results of the sphincter electromyograms and pressure recordings, it provides much diagnostic information in this group of patients. The high frequency activity is similar to that of striated muscle.

Electromyography↗
PubMed1975

The effect of adrenergic blocking drugs on outflow resistance.

Alpha blockade at a dose which produces minimal cardiovascular effects causes a significant fall in the urethral pressure profile in man. No change in profile height has been seen following the administration of a beta blocking drug in a dose producing cardiovascular changes of a similar order of magnitude.

Adult↗
PubMed1975

Urodynamic findings in adult females with frequency and dysuria.

Urodynamic findings, and in particular measures of outflow obstruction in a consecutive series of 156 women presenting with recurrent increased frequency and dysuria, have been analysed. Poor correlation between these various measures has been demonstrated; at most only 8% of these patients have demonstrable outflow obstruction. More than a quarter of the patients had bladder instability.

Adolescent↗
PubMed1975

Computer analysis of electromyographic signals from the human bladder and urethral and anal sphincters.

An investigation has been made into the form of the EMG signals from the human bladder and urethral and anal sphincters. A buildup of the low frequency detrusor EMG before micturition occurs in some patients and this is more marked in patients with urgency. A good correlation occurs between the amount of EMG activity and bladder activity as assessed by the cystometrogram. Marked spike activity has been seen in the detrusor EMGs of patients with irritable bladders. The comparison of anal and urethral sphincter EMGs is of interest from the viewpoint of the anatomy of the urethral sphincter and the mechanism of micturition.

Adolescent↗