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Biomedical subjects

W A Walters

Publications and source records attributed to W A Walters.

At least 73 records · Page 4Linked to original sources
PubMed1981

Gel filtration separation of bound and free antigens in radioimmunoassay of prostaglandin F2 alpha.

A technique applying the principles of gel filtration to separate the antibody-bound antigen for radioimmunoassay of PGF2 alpha is described. The procedure involves addition of the entire assay incubate to a column of Sephadex G-75 and elution of the antibody-bound fraction directly into a scintillation vial. Subsequent rinsing elutes the free fraction enabling the column to be re-used. The validity of this method for the direct measurement of PGF2 alpha in a standard tissue culture medium is demonstrated and its advantages over other separation techniques discussed.

Antigens↗
PubMed1981

Cigarette smoke inhalation specifically inhibits depressor responses to prostacyclin in the rat.

Studies have been made of the effects of prior exposure to cigarette smoke on cardiovascular responses of the anaesthetized rat to arachidonic acid, prostaglandin E2 (PGE2), PGF2 alpha and PGI2. When compared with a control group, falls in systolic and diastolic blood pressure and tachycardia following intravenous PGI2 were significantly reduced in those animals exposed to smoke 1 and 24 h previously. Responses 48 h after exposure were not significantly different. Pressor effects of PGF2 alpha and depressor responses to arachidonic acid and PGE2 were not significantly affected these times. It is suggested that the specific and long lasting attenuation of the effects of PGI2 which occurs following cigarette smoke inhalation could contribute to both acute cardiovascular changes and the circulatory diseases associated with smoking.

Animals↗
PubMed1980

Importance of early diagnosis and gonadectomy in 46, XY females.

Gonadal neoplasms developed in three 46, XY females aged 3 yr and 10 mo, 15 yr, and 19 yr. One patient died from metastatic neoplasia. Early diagnosis of 46, XY gonadal dysgenesis is essential, and should be considered in female infants and children with any features of Turner's syndrome, ambiguous genitalia, phallic hypertrophy, excessive height, large hands and feet, failure of development of secondary sexual characteristics, primary amenorrhea, abdominal mass, or unexplained hypertension. Any female with gonadal dysgenesis and a Y chromosome in her karyotype should have prophylactic gonadectomy as soon as possible. The absence of Sertoli cells in these patients, causing lack of androgen binding protein with deficient local concentration of androgens and consequent failure of maturation of spermatogonia, may lead to unregulated proliferation of germ cells, and hence explain the frequency of gonadal neoplasia in the 46, XY female.

Adolescent↗
PubMed1980

Fetoscopy. A new technique for antenatal intrauterine diagnosis.

The new technique of fetoscopy is an important advance in the antenatal intrauterine diagnosis of some fetal disorders. Because it enables fetal blood to be collected, fetoscopy has a major place in the intrauterine diagnosis of haemoglobinopathies, particularly fetal thalassemia major at 16-20 weeks' gestation in women at risk of bearing such a child.

Blood Specimen Collection↗
PubMed1979

Haemoglobin Bart's hydrops fetalis syndrome in an infant of Greek origin and prenatal diagnosis of alpha-thalassaemia.

An unusual case of Bart's hydrops fetalis is reported where the patient was born to parents of Greek origin. An exchange transfusion was given. Adult haemoglobin (HbA) was present in addition to HbBart's and HbPortland. A low level of synthesis of alpha-chains was evident. The mother presented again in a subsequent pregnancy for prenatal diagnosis of thalassaemia. The fetus was diagnosed as an alpha-thalassaemia carrier, a diagnosis which was confirmed at birth. The nature of alpha-thalassaemia in the family is discussed.

Australia↗
PubMed1979

Haemodynamics of mild hypertension in pregnancy.

One hundred and sixty-three haemodynamic studies were done serially in 23 normotensive and 25 mildly hypertensive women during pregnancy. With all subjects resting in the left lateral position, heart rate, cardiac output, stroke volume, left ventricular work index, total peripheral vascular resistance and haematocrit were all significantly higher while plasma volume per unit body weight was significantly lower in the hypertensive than in the normotensive pregnant women. It is postulated that this hyperkinetic circulatory state is due to hyperactivity of the sympathetic adrenergic component of the autonomic nervous system in hypertensive pregnancy.

Adolescent↗
PubMed1979

Subjective recording of fetal movement.

A group of 137 patients, 113 of whom had obstetric complications, recorded fetal movements by a subjective method. Low fetal movement counts were associated with maternal cigarette smoking and prolongation of pregnancy and high counts with maternal ingestion of sedatives or tranquillizers, abnormal fetal heart rate in labour and a true knot in the umbilical cord. The absence of fetal movement during four consecutive 20-minute counting-sessions was not associated with poor fetal outcome. Further investigations to assess the usefulness of fetal movement counting are recommended. Such investigations should take into account the limitations imposed by the methods and the obstetric population for study.

Birth Weight↗
PubMed1979

Release of prostaglandins during contraction of the human umbilical vein on reduction of temperature.

Flow rate was measured through the vein of the human isolated umbilical cord perfused at constant pressure (40 mmHg) at 37.5 degrees C and 20 degrees C. At the latter temperature the flow was decreased by 50.9% when compared with a mean of 201 ml/min at 37.5 degrees C indicating venospasm. Indomethacin (10 microgram/g) effected a highly significant reduction in the venous spasm caused by lowering the temperature. After indomethacin pretreatment, changing the cord temperature from 37.5 degrees C to 20 degrees C caused a mean decrease in flow of only 3.1%. When the effluent from the vein was passed over rat isolated stomach fundus and colonic strips, cooling of the cord was accompanied by contractions of the isolated tissues characteristic of prostaglandins. These results suggest that prostaglandins are involved in temperature-induced closure of the human umbilical vein after birth.

Cold Temperature↗
PubMed1979

Review: the significance and management of raised blood pressure in pregnancy.

Recent advances in the diagnosis, management and prognosis of hypertension in pregnancy are discussed, with emphasis on antihypertensive drug treatment. The use of diuretics, alpha-methyldopa, clonidine, hydrallazine, beta-adrenergic blockers, diazoxide, chlormethiazole, diazepam and heparin is given special attention.

Adrenergic beta-Antagonists↗
PubMed1979

Amniocentesis in the early second trimester of pregnancy and maternal anxiety.

Anxiety state and trait were measured before and after amniocentesis early in the second trimester of pregnancy, in a group of 28 women who were at risk of bearing an abnormal foetus. A significant decrease in maternal anxiety occurred in the majority of women after receiving the results of the amniocentesis. It is concluded that amniocentesis for intrauterine diagnosis of foetal abnormalities makes a significant contribution to the psychological wellbeing of those pregnant women who are at greater risk of having an abnormal baby.

Adult↗
PubMed1978

Responses of Australian patients with gynaecological disorders to the General Health Questionnaire: a factor analytic study.

One hundred and twenty-seven out-patients attending a gynaecology clinic completed the General Health Questionnaire (GHQ, 60-item version) and a role problems checklist (RPCL). Principal factors analysis of the GHQ yielded 8 factors which were named: poor performance (which accounted for 63.3% of total variance), depression-anxiety, sleep-disturbance, anhedonia anergia, loss of confidence, general illness, social dysfunction and headache. These results were compared with previous principal components analyses of the GHQ (Goldberg, 1972; Goldberg et al. 1976). A multiple regression analysis indicated that age and 7 of the 8 factors were significantly related to the number of role problems reported by the patients. However, it appears that psychiatric distress (as measured by the GHQ) and role problems were only related to a small degree (multiple R2 = 12.69% only).

Anxiety↗
PubMed1978

Blood pressure in the arm and leg in late pregnancy.

Arm and leg blood pressures were measured by an indirect sphygmomanometric method in 12 women in late pregnancy and the results were compared with those in 12 matched non-pregnant women. In most of the pregnant women the diastolic blood pressure measured in the leg fell significantly with a change in posture from the supine to lateral position. In contrast, no significant change was observed in arm blood pressure with postural change after correcting for hydrostatic pressure difference. The interpretation of these findings is discussed with particular reference to methodology of blood pressure measurement.

Adolescent↗
PubMed1977

A trial of oral ritodrine for the prevention of premature labour.

A double blind clinical trial of oral ritodrine for prevention of premature labour was conducted in 38 primigravidae in whom the internal os of the cervix was one or more fingerbreadths dilated at 28 to 32 weeks gestation. The results suggest that oral ritodrine may not be effective in preventing premature labour.

Adult↗
PubMed1977

Methods of recording fetal movement.

Patient, observer and instrumental methods for recording fetal movements are described. Significant correlations between both patient and observer, and patient and instrumental fetal movement counts, were found. Significant diurnal, daily and weekly variation in fetal movement counts occurred which need to be considered in the interpretation of the frequency of fetal movements as an indication of fetal welfare.

Circadian Rhythm↗
PubMed1977

Venous distensibility during the menstrual cycle.

Changes in the distensibility of dorsal hand veins during the menstrual cycle were measured in 19 healthy young women using a new optical method relying upon a pressure-diameter principle. Significantly greater venous distensibility was found during the first half compared with the second half of the menstrual cycle. The possible causes for this finding, particularly the role of oestrogen, are discussed.

Adult↗