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Biomedical subjects

A Davies

Publications and source records attributed to A Davies.

At least 253 records · Page 14Linked to original sources
PubMed1987

Assessment of PIC and MMPI scales in adolescent psychosis: a caution.

This study investigated the sensitivity of two frequently used multidimensional instruments--the Personality Inventory for Children (PIC) and the Minnesota Multiphasic Personality Inventory (MMPI)--in assessing psychotic states in adolescents. This issue arose as a result of the fact that the PSY scale on the PIC was constructed and cross-validated only on samples of children between the ages of 5 and 12 years. T-score comparisons between psychotic and nonpsychotic samples were performed, as well as Pearson correlations between PIC Psychosis (PSY) and MMPI Schizophrenia (Sc) scale T-scores. T-score comparisons indicated no significant differences between the groups on either PSY or Sc. A nonsignificant relationship between PSY and Sc scale elevations was also found. These results suggest the need for a profile-analytic approach to PIC and MMPI interpretation in identifying psychotic symptomatology in adolescents rather than PSY or Sc T-score elevation in isolation.

Adolescent↗
PubMed1986

Interface of panic and depression: clinical and sleep EEG correlates.

Four groups of subjects were compared with respect to their clinical and demographic status and electroencephalographic (EEG) characteristics, namely: primary major depressive disorder (PRI MDD); panic disorder (Panic); "Mixed" group comprising patients meeting full syndromal criteria for MDD and panic occurring concomitantly; and normal controls. The "Mixed" (MDD + Panic) patients were characterized by earlier age of onset of psychiatric illness, longer duration of current episode, greater intensity of symptoms, higher impairment of functioning, increased miscellaneous psychopathology, and greater objective stress and anger. With respect to sleep EEG variables, PRI MDD patients were clearly different from the other three groups. The sleep profile of the "Mixed" group occupies an intermediate position between the "pure" Panic and MDD groups. Classification of the "Mixed" patients based on the discriminant function coefficients of the Schedule for Affective Disorders and Schizophrenia and sleep analysis of the "pure" groups (PRI MDD and Panic) reveals that some patients are classified as true PRI MDD while others are classified as falling somewhere along the PRI-MDD/Panic spectrum. The separation of the PRI MDD from Panic and Normals, however, is clear, suggesting that sleep can be successfully used as a physiological marker in the separation of these conditions.

Adult↗
PubMed1986

A role of pulmonary rapidly adapting receptors in control of breathing.

We analysed the breathing pattern of anaesthetised rabbits during unloaded breathing when breathing was accelerated by inspired CO2 and when they breathed against positive or negative pressures before and during block of pulmonary stretch receptors by SO2, and after bilateral vagotomy. Before block moderate steps of inflation or deflation (0.5 kPa) produced relatively larger changes in duration of expiration than in duration of inspiration, indicating the relative sensitivities of the two phases. With stretch receptors, blocked inflation or deflation shortened expiration, demonstrating the influence of rapidly adapting receptors on that phase of breathing. If pulmonary stretch receptors were the major determinants of the duration of inspiration, we would have expected inspiratory duration in the stretch receptor blocked and vagotomised states to be almost identical. They were not, inspiratory duration being less in the blocked than in the vagotomised state. Possibly vagal afferent activity other than that of stretch receptors shortens inspiratory duration. However, we have found that rapidly adapting receptor activity (and any unmyelinated fibre activity provoked by rapid inflation or deflation of the lungs) never directly shortened inspiration. We therefore propose a mechanism whereby rapidly adapting receptors may indirectly affect duration of inspiration.

Adaptation, Physiological↗
PubMed1986

The influence of vagotomy on the respiratory effects of injected phenyl diguanide in anaesthetized rabbits.

The effects of intravenous injections of phenyl diguanide (PDG) on pattern of breathing were studied before, immediately after, and some time after bilateral cervical vagotomy in anaesthetized rabbits. The characteristic tachypnoea observed in the intact animals could not be produced for several minutes after bilateral vagotomy, but after 15 min could be elicited again. This sequence of events was not essentially modified by cutting the glossopharyngeal nerves nor by injection of local anaesthetic into the pericardial sac. We suggest that the respiratory effects of PDG in the rabbit, previously considered to originate mainly from peripheral receptors, including those of the lungs, has a considerable central component which has previously been obscured by the short-term effects of vagotomy.

Anesthesia, General↗
PubMed1985

Urinary catecholamine levels in the newborn infant.

The urinary concentrations of dopamine, noradrenaline and adrenaline were measured by a radioenzymatic method in 212 full-term and premature newborns. The ranges, means and standard deviations from birth to 4 days + are presented. The excretion of dopamine was ten times that of noradrenaline or adrenaline. The absolute concentrations of each catecholamine were reduced as birth weight decreased. The values were increased in babies with fetal distress. Any changes found in hypoglycaemic or jaundiced infants were attributable to prematurity. Very high levels were found in a few infants given tolazoline. We speculate that the role of dopamine production and excretion in the newborn has been underestimated. Dopamine may have an important role to play in the homeostatic mechanisms of the newborn.

Catecholamines↗
PubMed1985

Bone loss in autoimmune chronic active hepatitis on maintenance corticosteroid therapy.

To determine the frequency of osteoporosis in patients with autoimmune chronic active hepatitis who are maintained on corticosteroids, both cortical and trabecular bone loss were studied in a group of 36 patients. A significant decrease in both the total trabecular bone volume (p = 0.005) and cortical plate thickness (p = 0.01) of iliac crest biopsy specimens was found in the patients with chronic active hepatitis. Bone mineral content of the radial metaphysis, a site composed of both cortical and trabecular bone, was found to be significantly decreased (p = 0.05). However, no statistical reduction in cortical bone mass of the radial diaphysis and second metacarpal was detected. Altogether, 47% of patients had evidence of either excessive trabecular or cortical bone loss, or both, as judged by histologic and radiologic criteria. The presence of cirrhosis at the time of diagnosis or subsequently did not appear to lead to greater loss of bone mass. However, a weak inverse correlation was found between the product of mean dose and duration of corticosteroid therapy and both the trabecular bone volume and the cortical plate thickness of the iliac crest biopsy specimens. Based on these results, patients with autoimmune chronic active hepatitis on low doses of prednisolone therapy may need to be treated with calcium and vitamin D at an early stage of their disease.

Adrenal Cortex Hormones↗
PubMed1985

Quantitative effects of defaunation on rumen fermentation and digestion in sheep.

Studies on the quantitative significance of protozoa on carbon and nitrogen digestion and metabolism in the rumen were carried out in sheep given a diet of pelleted concentrate (500 g/d) and chopped hay (500 g/d). Measurements were made of apparent digestibility; flows of organic matter and dietary and microbial non-ammonia N (NAN) (using 15NH4+) to the duodenum; and rates of production, interconversion and metabolism of the major C fermentation end-products (from mathematical modelling of 14C isotope values). The population density of bacteria in the rumen increased as a result of defaunation (28.6 compared with 8.2 X 10(9) organisms/ml). This high density was associated with greater utilization of volatile fatty acids (VFA) within the rumen. The rate of irreversible loss (IL) of bicarbonate + carbon dioxide from the rumen was greater in the defaunated animals (98.5 v. 57.2 g C/d) but the IL from the blood was greater in the faunated group (138.6 v. 106.1 gC/d). This is consistent with the hypothesis that the high population density of bacteria found in the rumen fluid of defaunated animals may result in increased fermentation of rumen VFA and digestible dietary carbohydrate, thereby increasing the output of CO2 from the rumen and reducing the quantity of VFA (hence energy) available to the host. There was no difference in the flow of organic matter (OM) to the duodenum but there was a higher faecal excretion of OM in defaunated animals (apparent OM digestibility: 0.72 in faunated, 0.67 in defaunated). Defaunation did not significantly increase the flow of NAN to the duodenum, the percentage of duodenal NAN of bacterial origin or the quantity of microbial NAN synthesized/g organic matter fermented. Faecal excretion of NAN was higher in defaunated animals (5.3 v. 3.6 g N/d).

Animals↗
PubMed1985

Microcrystalline hydroxyapatite compound in prevention of bone loss in corticosteroid-treated patients with chronic active hepatitis.

To determine whether microcrystalline hydroxyapatite compound (MCHC) could reduce bone loss or its consequences in patients with chronic active hepatitis (CAH) on corticosteroid therapy, a controlled trial was conducted in 36 such patients over a period of 2 years. Both skeletal symptoms (back pain) and fractures were uncommon during the trial period but both showed non-significant differences in favour of the MCHC group and biochemical investigations were suggestive of a reduction in parathyroid over-activity. Continued reduction in bone mineral content of the radius (photon absorptiometry) was halted in those receiving MCHC and iliac crest bone biopsy showed a non-significant increase in trabecular bone volume. The fall in iliac crest cortical plate thickness was significantly less (P less than 0.025) in the MCHC group and the results overall were consistent with a beneficial effect from MCHC in corticosteroid-induced osteoporosis.

Adult↗
PubMed1985

Osteoporosis in chronic cholestatic liver disease.

Assessment for both trabecular and cortical osteoporosis was carried out in 36 unselected patients with chronic cholestatic liver disease of whom a number had received corticosteroids during the course of their illness. Symptoms suggestive of osteoporosis were present in 42 per cent of patients of whom 11 per cent had evidence of one or more wedged or collapsed vertebrae. There was a highly significant decrease in the cortical area (total area ratio of the second metacarpal (p = 0.05), bone mineral content at the metaphyseal site of the radius (p = 0.01) and the total trabecular bone volume of the iliac crest biopsies (p = 0.005) in the 31 female patients when compared with age and sex-matched healthy controls). There was a nonsignificant decrease in total trabecular bone volume of the iliac crest and bone mineral content of the radial metaphysis in the males compared with age and sex-matched controls but the cortical plate thickness of the iliac crest (p = 0.005) and bone mineral content of the radial diaphysis (p = 0.02) were significantly higher. In total, 42 per cent of patients had evidence of either excessive cortical (28 per cent) and/or trabecular (36 per cent) bone loss as judged by radiological and histological criteria. Only the total trabecular bone volume of the iliac crest, of all the parameters measured was significantly (p = 0.02) lower in patients with backache compared with those without back pain. Significantly greater bone loss was demonstrated at all sites measured in those patients that were receiving or had received corticosteroids in the past.

Adrenal Cortex Hormones↗
PubMed1984

Relation of target encounter and neuronal death to nerve growth factor responsiveness in the developing mouse trigeminal ganglion.

An aim of this study was to define precisely the period in the developmental history of primary sensory neurons during which nerve growth factor (NGF) exerts its growth-promoting effect. The mouse trigeminal ganglion and its peripheral projection were studied at closely staged intervals throughout development using light and electron microscopy, and the influence of NGF and anti-NGF antiserum on neurite outgrowth from ganglion explants was investigated at corresponding stages in culture. By embryonic day 9.5 (E9.5) peripheral fibers were first visible and increased in number until E13. Throughout this period in vitro neurites grew in the presence of anti-NGF. Peripheral fibers initially contacted the epithelium of the mandibular process by E10.5 and the maxillary process by E11. This coincided with the stage in vitro during which the magnitude of neurite outgrowth was significantly increased by NGF. The development of this response was independent of target encounter since it occurred in neurons which had not contacted their targets prior to explantation. There was an approximate one-to-one relationship between the number of neurons in the ganglion and peripheral fibers throughout development. A peak of some 44,400 fibers and 42,600 neurons was reached by E13 and fell to 20,800 and 19,000, respectively, by birth. Neurite outgrowth was elicited by NGF throughout the period of neuronal death. It is argued that the time course of the influence of NGF is consistent with a role as a selective maintenance factor but not as an agent directing initial outgrowth.

Aging↗
PubMed1984

Aberrent group B reactions detected in mixtures of semen and vaginal secretions possibly due to acquired B.

Routine ABO grouping tests performed on vaginal swabs from a group O female showed the presence of blood group B activity as well as the expected A and H activity after intercourse with her group A partner. The source of the B activity was readily detectable using the Laboratory's routine elution test, but it was not detectable when a monoclonal anti-B was used and detection by the inhibition technique was possible only with a selected antiserum. A possible explanation of the reactions observed is that the acquired B is capable of reacting with only a portion of the antibodies present in normal polyclonal anti-B sera.

ABO Blood-Group System↗