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Biomedical subjects

D J Taylor

Publications and source records attributed to D J Taylor.

At least 19 recordsLinked to original sources
PubMed1992

Ultrasonographic study of early embryonic loss induced by Actinomyces pyogenes in cattle.

Four cows were inoculated into the uterus with Actinomyces pyogenes between 30 and 41 days of gestation. Gross morphological changes were monitored by rectal palpation and with a realtime B-mode two-dimensional scanner with a 7.5 MHz transrectal linear transducer, shortly before infection and afterwards at three to 12 hours intervals. Two control groups of cows 27 to 50 days pregnant were used: two cows were inoculated with 6 ml of sterile saline into the uterine lumen and four cows were treated with cloprostenol (prostaglandin F2 alpha analogue). There was a change in the uterine fluid from a black, non-echogenic image before infection to a grey or cloudy echogenic image as early as 21 hours after infection. There was an increase in the thickness of the endometrium of the horns and body of the uterus. The embryonic membranes thickened and separated from the endometrium as early as four hours after infection, followed by cessation of the embryonic heart beat, opening of the cervix and abortion. Abortion was followed by an increase in the amount of echogenic intrauterine fluid leading to an increase in the size of the uterus, and the cervix remained open for at least eight days. The area of the corpus luteum remained greater than 2 cm2 throughout the whole period. Intrauterine inoculation with sterile saline had no effects, but the administration of cloprostenol was followed by the death of the embryo and abortion within 72 hours, and the regression of the corpus luteum from greater than 2 cm2 at treatment to 0.4 cm2, 24 hours after abortion.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Veterinary↗
PubMed1992

Changes in brain amine levels associated with the morphological and behavioural development of the worker honeybee.

Changes in biogenic amine levels associated with the morphological and behavioural development of the worker honeybee are examined. A significant increase in amine levels in the head of the honeybee is associated with transition from the larval to pupal stage. Adult emergence is also accompanied by a significant increase in 5-HT levels in the brain, but no significant change in brain dopamine (DA) levels. NADA (N-acetyldopamine) levels increase during larval and pupal development, but in contrast to both DA and 5-HT, drop significantly during the transition from pupa to adult. Levels of DA in the brain of nectar and pollen forager bees, presumed to be among the oldest adults sampled, were found to be significantly higher than in nurses, undertakers or food storers. These results suggest that an age-dependent change in amine levels occurs in the brain of the worker bee. In the optic lobes, levels of DA and 5-HT were found to be significantly higher in pollen forager bees than in all other behavioural groups. Significant differences in amine levels in the optic lobes of nectar foragers and pollen foragers indicate that some differences in amine levels occur independent of worker age. The functional significance of differences in brain amine levels and whether or not biogenic amines play a direct role in the control of honeybee behaviour has yet to be established.

Aging↗
PubMed1992

A comparison of clinical features in trichotillomania and obsessive-compulsive disorder.

Trichotillomania (TM) recently has been conceptualized as a variant of obsessive-compulsive disorder (OCD). However, no systematic data have compared the clinical features of these two disorders. Here we report data from 8 TM and 13 OCD patients which suggest important clinical differences between groups. First, TM patients reported a significantly greater degree of pleasure during hair-pulling than OCD patients reported during performance of ritualistic behaviors. Second, TM was accompanied by significantly fewer associated obsessive-compulsive symptoms. Third, the groups differed with regard to other clinical features including anxiety, depression, and personality characteristics. We conclude that TM is not conceptualized best as a variant of OCD.

Adult↗
PubMed1992

Human muscle cell denervation: the results of a 31-phosphorus magnetic resonance spectroscopy study.

The results presented here demonstrate that there is a major abnormality of high and low energy phosphate metabolism in muscle following peripheral nerve damage. Using 31-phosphorus magnetic resonance spectroscopy the changes in phosphocreatine, adenosine triphosphate, inorganic phosphate and metabolites of membrane metabolism could be observed in vivo in human subjects. The data indicate that there may be a metabolic myopathy in the muscle cells after nerve injury. Further, the metabolic changes did not always return to the control level, indicating a persistence of the abnormality. This failure of the metabolic function of the cells may be important in determining the ultimate outcome of peripheral nerve surgery.

Adenosine Triphosphatases↗
PubMed1992

Cellular energetics in hypothyroid muscle.

Skeletal muscle of seven hypothyroid patients was investigated in the resting state and during exercise and recovery using 31P magnetic resonance spectroscopy. The bioenergetics and intracellular pH of the hypothyroid muscle were thus evaluated and compared with results from normal muscle and muscle of patients with mitochondrial myopathy. In resting hypothyroid muscle there were significant elevations in the concentration ratios of phosphocreatine/ATP and inorganic phosphate/ATP, while phosphocreatine/inorganic phosphate and intracellular pH were lower than normal. In exercising hypothyroid muscle, energy stores were depleted more rapidly and acidification began later than in normal muscle. Recovery of phosphocreatine to the pre-exercise value was normal, but intracellular pH recovered slowly. The data suggest that in the hypothyroid state, glycogen breakdown in skeletal muscle was delayed thereby limiting the substrate supply for both glycolytic and oxidative production of ATP at the beginning of exercise. There was no evidence for a decrease in the oxidative capacity of the muscle of our patients, but elevated ADP may have stimulated oxidative metabolism and helped to compensate for low mitochondrial content. The low intracellular pH in resting muscle and the slow pH recovery after exercise imply that proton handling was abnormal in the hypothyroid muscle.

Adult↗
PubMed1992

Bio-energetic changes in human gastrocnemius muscle 1-2 days after strenuous exercise.

[31P]magnetic resonance spectroscopy was used to study the metabolic sequelae of intense muscular activity in gastrocnemius of seven subjects 1-2 days after a 67-mile bicycle ride. The muscle was examined at rest, during a test exercise and during recovery from test exercise. Post-ride and pre-ride results were compared. At rest, the ratio of phosphocreatine to ATP (PCr/ATP) was increased post-ride; during test exercise PCr/(PCr+Pi) was lower post-ride; and the recoveries of PCr, Pi and PCr/(PCr+Pi) after test exercise were delayed, with decreased 'overshoot' of PCr/(PCr+Pi) (which is due to recovery of Pi to below its resting value). Mild mitochondrial damage (perhaps due to exposure to high cytosolic [Pi] during the bicycle ride) may explain some of these results. In contrast to reports of largely eccentric exercise there was no increase in resting Pi/ATP. We have thus demonstrated perturbations of muscle bio-energetics 1-2 days after strenuous exercise, in the absence of convincing enzymological evidence of muscle damage.

Adult↗
PubMed1992

Isolation of a mucoid alginate-producing Pseudomonas aeruginosa strain from the equine guttural pouch.

The isolation and characterization of a mucoid, alginate-producing strain of Pseudomonas aeruginosa from a nonhuman host, namely, in chondroids from an equine guttural pouch, is reported for the first time. Pure cultures of P. aeruginosa 12534 were isolated from a 17-month-old pony mare with a history of chronic bilateral mucopurulent nasal discharge from the right guttural pouch. Transmission electron microscopy of chondroids showed mucoid P. aeruginosa growing as microcolonies within a matrix of extracellular material. On the basis of expression of the mucoid phenotype under different growth conditions, P. aeruginosa 12534 belongs to group 1 and resembles other isolates carrying the muc-23 mutation. The bulk of the extracellular material was characterized as being alginate by chemical and 1H nuclear magnetic resonance analyses, which showed that it had a composition similar to that produced by isolates of P. aeruginosa from human patients with cystic fibrosis.

Alginates↗
PubMed1992

Perinatal mortality and morbidity--the Scottish perspective.

Although perinatal mortality has continued to fall in Scotland during the last decade, there has been little change during the last three years i.e. 8.9, 8.9, 8.7 per thousand births respectively. Many deaths still result from antepartum haemorrhage and unknown causes so the Scottish Perinatal Mortality group is undertaking a confidential enquiry into the deaths of all normally formed infants of birthweight greater than 2500 g. The other major cause of prenatal death i.e. preterm delivery is also associated with a significant risk of neurological impairment. Results from the Scottish Low Birthweight Study show that 5.7 per cent and 9.5 per cent of very low birthweight infants have severe and moderate disability respectively, reveal once again the importance of research into the primary and secondary prevention of preterm delivery and the care of the preterm neonate.

Birth Weight↗
PubMed1992

HIV risks among minority drug users in a small city.

In 1989, African-American and Mexican-American drug users (n = 220) in a small southern city were interviewed, in street settings, about their HIV behavioral risks and their readiness to reduce risks. Both ethnic groups contained large numbers of cocaine and heroin users. Mexican Americans were more likely to use heroin, prefer injection, and share needles with other drug users than were African Americans. Sexual risk-taking in both groups was high, with very low levels of condom use, high levels of exchanging sex for drugs and money, and high levels of having multiple sexual partners. Mexican Americans were more likely than African Americans to have regular partners who used drugs. Intravenous drug users in both ethnic groups were at high risk for HIV infection, reporting high levels of multiple drug use, daily drug use, needle sharing, never cleaning needles, and exchanging sex for drugs or money. Readiness to reduce HIV risks was also high in both groups, as evidenced by the response to questions about the use of free preventive services, HIV testing, and concern about AIDS. Implications for research and preventive programs among minority drug users in small cities are discussed.

Adult↗
PubMed1992

Inflammatory cytokines stimulate glucose uptake and glycolysis but reduce glucose oxidation in human dermal fibroblasts in vitro.

Interleukin-1 alpha (IL-1 alpha) produced alterations in human dermal fibroblast glucose metabolism in vitro of the type seen in severe sepsis in man. Glycolysis and glucose uptake were increased but the oxidation of glucose within the tricarboxylic acid (TCA) cycle was reduced. The combined addition of tumour necrosis factor alpha (TNF alpha) with interferon-gamma (IFN-gamma) similarly increased the dependency for cellular energy provision from an oxidative to the glycolytic state. These cytokine-induced changes in glucose metabolism were unaffected when prostaglandin production was inhibited with a cyclo-oxygenase inhibitor, but were significantly reduced by the steroid dexamethasone. Thus, the inflammatory cytokines IL-1 and TNF alpha reportedly detected in the circulation during severe sepsis may directly affect not only glucose uptake but also its subsequent metabolism within tissue fibroblasts.

Biological Transport↗
PubMed1991

Experimental reproduction of acute lesions of porcine pleuropneumonia with a haemolysin-deficient mutant of Actinobacillus pleuropneumoniae.

The role of the heat-labile haemolysin of Actinobacillus pleuropneumoniae in acute porcine pleuropneumonia was examined. A virulent strain was compared with an isogenic haemolysin-deficient mutant in experimental infections. The pigs which received the virulent strain showed clinical signs of acute respiratory disease whereas the animals infected with the mutant strain appeared to be less severely affected. At post mortem examination, both groups showed similar acute pulmonary lesions and pleurisy typical of A pleuropneumoniae infection. The bacterial antigen representing the haemolysin was detected in lung lesions infected with the parent strain but not in those infected with the mutant. These results demonstrate that the haemolysin of serotype 2 A pleuropneumoniae is not an essential factor for the production of the lesions of pleuropneumonia in pigs.

Actinobacillus Infections↗
PubMed1991

Early abortion in cattle induced by experimental intrauterine infection with pure cultures of Actinomyces pyogenes.

Actinomyces pyogenes from a case of endometritis was used to study the effects of infection of the bovine embryo between days 27 and 41 of pregnancy. From 10(9) to 10(10) washed organisms were introduced into the uterine lumen of four pregnant cows. Two pregnant cows were inoculated with sterile saline and four pregnant cows were treated with cloprostenol. Embryonic death and abortion followed 29 to 144 hours after the inoculation of the live bacteria. The aborted embryos were macerated or clearly degenerating and yielded profuse pure cultures of A pyogenes. Abortion was accompanied by a sustained increase in uterine tone, opening of the cervix, presence of vaginal pus and a vulval discharge and the persistence of the corpus luteum for at least eight days after abortion. Intrauterine inoculation with saline did not affect pregnancy, but embryonic death, abortion and regression of the corpus luteum occurred 66 to 72 hours after the treatment with cloprostenol. The results suggest that A pyogenes is a primary pathogen and is capable of causing embryonic death and abortion.

Abortion, Veterinary↗