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Biomedical subjects

A Walker

Publications and source records attributed to A Walker.

At least 307 records · Page 17Linked to original sources

Dietary fibre in under- and overnutrition in childhood.

Children in developing countries pass stools that are very different from those passed by children in Europe. These stools reflect a diet of unrefined carbohydrate with low-energy density, and which due to the large volume results in an energy deficit in the child. This energy deficit is now considered to be the major cause of the almost universal undernutrition. Much of the improved health in European children during the last century has probably arisen through better nutrition due to more-refined carbohydrates and to more fat in the diet. Over the same period as children have become healthier, diseases of civilisation have appeared. One factor in such diseases is clearly that of diet, and these diseases may partly be caused by the high-energy density and the low-dietary fibre content. Changes in diet offer the greatest hope for a rapid improvement in health. In the developing world we need to find a means for making foods with a high-energy density more easily available to overcome the undernutrition in childhood. In industrialised countries older children need to become accustomed to a diet of lower-energy than at present, containing more unrefined carbohydrate and less fat.

Adolescent↗

Ingestion of formic acid-containing agents--report of three fatal cases.

Three patients were treated after they had deliberately ingested domestic agents containing formic acid. The major complications included the local effects on the oropharynx, oesophagus and stomach, metabolic acidosis, derangement of clotting mechanisms with haemorrhage and shock, widespread intravascular haemolysis, disseminated intravascular coagulation and the acute onset of respiratory and renal failure. All 3 patients died between 2 and 14 days after admission. It is the authors' belief that intensive therapy from the outset to include exchange transfusion, infusion of clotting factors, high dose steroids, ventilatory support and peritoneal or haemodialysis with parenteral nutrition may perhaps offer a better chance for survival.

Adult↗

Type I (insulin-dependent) diabetic multiplex families: mode of genetic transmission.

HLA genotypes have been analyzed in 120 classic type I (insulin-dependent) diabetic sib pairs with an age of onset below 16 yr reported to the British Diabetic Association register (1972--78). By this age, siblings of diabetic children are 26 times more likely to develop type I diabetes than other children. There is a highly significant disturbance in the zygotic assortment of HLA haplotypes in these sib pairs, providing conclusive evidence for the existence of major susceptibility genes in the HLA complex. The present data exclude a simple dominant or recessive model of inheritance. It is likely that both parents contribute to the susceptibility, indicating the presence of two HLA-linked genes (or clusters of genes in linkage disequilibrium) that influence the predisposition to the disease. There is no evidence that type I diabetic multiplex families have an increased HLA risk or increased predisposition to autoimmunity compared with families with one affected child.

Adolescent↗

Acceleration of the fetal heart rate.

Acceleration of the fetal heart rate during contractions was usually followed by deceleration, and evidence is presented to show that it results from increased sympathetic drive and may be associated with fetal tissue hypoxia. However, the presence of accelerations are not serious and merely warn the obstetrician of the possibility of the occurrence of subsequent decelerations. The mechanism thought most likely to produce accelerations is uterine compression of the umbilical vein during contractions.

Bradycardia↗

Prognostic factors in metastatic and hormonally unresponsive carcinoma of the prostate.

Eighty-eight patients with hormone-resistant Stage IV prostate cancer were treated with a five-drug chemotherapy program. Patient demographic data, prior therapy, symptoms, extent of disease, and laboratory studies were analyzed statistically to evaluate the association of these parameters with survival from the onset of chemotherapy. Factors associated with short survival included age greater than 65, severe bone pain, poor performance status, presence of soft tissue metastases, anemia, elevation of serum LDH, SGOT, alkaline and acid phosphatases, and prolactin, and hypoalbuminemia. Race, stage at initial diagnosis, prior radiation therapy, prior orchiectomy, and elevation of CEA had no prognostic association. We suggest that clinical trials of new therapies of hormone-resistant prostate cancer take into account the presence of these prognostic factors in the analysis of the results of therapeutic programs.

Aged↗

Development of the perception of invariants: substance and shape.

Three experiments investigated the perception of substance and shape as invariant properties of objects by three-month-old infants. In experiment 1, infants were habituated to two differently shaped objects undergoing a rigid motion. After habituation of the infants, the objects were presented undergoing a different rigid motion, or undergoing a deforming motion, or undergoing the same rigid motion. Habituation was maintained to the new rigid motion, indicating that the two rigid motions were perceived as sharing an invariant property. Dishabituation, on the other hand, occurred when a deforming motion followed a rigid one. In experiment 2, infants were habituated to one shape undergoing two different rigid motions. After habituation, the shape was changed but the same two motions continued. Dishabituation occurred, compared to a group with no shape change, indicating that shape is distinguished as an invariant property over two rigid motions. In experiment 3, habituation to a shape undergoing two rigid motions was followed by a new shape presented motionless, or the same shape presented motionless. Cessation of motion did not prevent recognition of shape as invariant. Two properties of an object, substance and shape, thus appear to be detectable as invariant in an event sequence, an instance of "phenomenal doubling" at an early age.

Child Development↗

A non-invasive method for recording His-Purkinje activity.

A simple non-invasive method for recording of activity from the His-Purkinje system (HPS) is described. The electrical activity was derived from bipolar orthogonal surface leads. The signal was strongly amplified, bandpass filtered, delayed and averaged in an analogue averager before presentation. The equipment is mobile. The characteristics of the equipment are described. There was good agreement between invasive and non-invasive recordings. Out of seventeen subjects studied ten had a measurable HPS signal. Muscle tension and deep breathing tended to obscure the non-invasive recordings. The best lead for the measurements was lead X.

Adult↗

Treatment of metastatic endocrine-unresponsive carcinoma of the prostate gland with multiagent chemotherapy: indicators of response to therapy.

Eighty-eight patients with metastatic and hormonally unresponsive carcinoma of the prostate gland were treated with a multiagent chemotherapy protocol. Because of the difficulty in evaluating the response of patients to therapy, data were collected in a prospective fashion and analyzed for clinical or laboratory changes that correlated with improved survivorship. Decrease of initially abnormal values of either acid or alkaline phosphotase into the normal range was associated with prolonged survival; weight gain of more than 10% was also associated with improved survival. Thirty-three patients demonstrated a fall of acid or alkaline phosphatase into the normal range or they increased their weight by at least 10%. The median survival time for this group of patients was 76.1 weeks as compared to 28.2 weeks for patients who failed to exhibit these changes. In future studies of the treatment of metastatic prostate cancer, these changes might be used as criteria of response to therapy.

Acid Phosphatase↗

Fluoride distribution in the facial surfaces of human maxillary central incisors.

The fluoride distributions in the incisal, middle and cervical regions of the facial surfaces of six maxillary central incisors were determined by three successive acid etch biopsy procedures. The fluoride concentrations were adjusted to standardized depths of 0--10 micron, 10--20 micron and 20--30 micron. In the biopsy areas the enamel fluoride concentrations decreased with increasing depth. In all the teeth the fluoride content was lowest in the incisal region and highest at the cervical third.

Dental Enamel↗

Mecrowear of mammalian teeth as an indicator of diet.

Microwear details on teeth of two sympatric species of hyrax are correlated with major dietary differences observed in the wild. Grazing (Procavia john-stoni) and browsing (Heterohyrax brucei) species can be distinguished. The results show that diets of extinct species may be deduced from tooth microwear.

Animals↗

Light output and X-ray attenuation measurements for some commercial intensifying screens.

The spectral content and intensity of light emission together with the x-ray attenuation have been measured for a selection of commercially available intensifying screens used in diagnostic radiology. Incident x-ray beam qualities with half value layers between 3.8 to 10 mm AI were employed in order to simulate a wide range of clinical situations. The measurements of spectral content demonstrate the wide variations in spectral emission which now exist between screens employing different phosphor materials. Similarly, a wide variation in the intensity of light emission is observed for screens employing different phosphor materials and also for screens employing the same material. The interrelation of the measured physical properties affects both the system speed and noise properties and needs to be considered when comparing the performance of different systems.

Radiographic Image Enhancement↗

Stereometric craniometry.

A method is described whereby three-dimensional co-ordinates of points on a cranium can be recorded in terms of azimuth, elevation and radial distance from a selected point. These co-ordinates can be used to create two-dimensional representations of single crania, the differences between many crania or growth stages of individuals or series of individuals. The co-ordinates can be used in more conventional analytic ways in the same way as cartesian co-ordinates.

Animals↗

A report on the use of Arvin in patients with pre-gangrene of the lower limb.

Sixteen patients with arteriosclerosis and pre-gangrene of a lower limb were treated for 5 days by intravenous injection of Arvin. The effects of the injection on plasma fibrinogen, the viscosity of blood and the patient's symptoms were measured. There was a 90 per cent reduction in plasma fibrinogen and a significant reduction in the viscosity of blood. Five patients experienced some relief of pain during the treatment. In only one patient were the symptoms relieved permanently.

Adult↗