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Biomedical subjects

M Davies

Publications and source records attributed to M Davies.

At least 415 records · Page 23Linked to original sources
PubMed1986

Hypothesis: blocking factors and human pregnancy: an alternative explanation for the success of lymphocyte transfusion therapy in abortion-prone women.

Recent evidence has demonstrated that the non-specific immunosuppression that develops during pregnancy is not due to the de novo synthesis of immunosuppressive factors (ISF) but is a result of the activation of pre-existing molecules. The latter are present in normal sera as inactive complexes with a molecule which is specifically depleted following conception resulting in the activation of the ISF; the depleted molecule is termed the pregnancy-depleted immunoregulatory factor (pdIRF). Since non-specific ISF are detected in various diseases, it is proposed that the ISF-pdIRF relationship observed in pregnancy is a universal phenomenon and that the depletion of pdIRF and the activation of ISF can be achieved by a variety of stimuli. It is further proposed that abortion-prone women fail to adequately deplete their pdIRF levels so that the ISF are not activated. However, owing to the universal nature of the system, lymphocyte transfusion therapy supplies the necessary stimuli so that the pdIRF levels are depleted and the ISF activated which ensures a successful outcome to the pregnancy.

Abortion, Habitual↗
PubMed1986

Health risks associated with wastewater irrigation: an epidemiological study.

An analysis of morbidity was made in 11 kibbutzim (cooperative agricultural settlements), with a total population of 3,040, that had switched from nonwastewater to wastewater sprinkler irrigation or vice versa. Generally, partially treated stabilization pond effluent of poor microbial quality was used for irrigation. Vegetables or salad crops were not irrigated with effluent. The results showed that a seasonal, twofold, excess risk of "enteric" disease was found in the 0 to 4 year-old age group during the summer irrigation months in those years in which wastewater was used for irrigation, compared with the parallel summer months of nonwastewater irrigation years in the same kibbutz. On the year round rates basis, little or no excess enteric disease was found in wastewater irrigating communities.

Adolescent↗
PubMed1986

Host defence in continuous ambulatory peritoneal dialysis: the effect of the dialysate on phagocyte function.

Peritoneal dialysis fluid was examined after dwell periods of from 30 min to 18 h. Macrophages formed more than 70% of all cells recovered, irrespective of dwell time. The viability of these cells was 95% or greater even in 30 min effluent. Peritoneal macrophages and polymorphonuclear leucocytes were incubated in unused peritoneal dialysis fluid. By 30 min the viability of polymorphonuclear leucocytes had fallen to 50% but that of peritoneal macrophages was still 84%. However, phagocytosis of unopsonized zymosan by both cell types was depressed after only 10 min exposure. Peritoneal dialysis effluents obtained after dwell times of 30-180 min were examined for their effect on phagocytosis in vitro. These fluids suppressed peritoneal macrophages function as compared to RPMI 1640. Effluent after an overnight dwell did not affect phagocytosis. The suppressant effect decreased with increasing dwell time. Polymorphonuclear leucocytes were affected to a greater degree than peritoneal macrophages. Tests showed that this decreased phagocytosis was not due to cell death nor was it due to the osmolality or lactate content of the dialysate. Adjusting pH only improved cell function slightly. Phagocyte function appears to be depressed for clinically significant periods of the CAPD cycle.

Humans↗
PubMed1986

Intra-spinal new bone formation and spinal cord compression in familial hypophosphataemic vitamin D resistant osteomalacia.

Four patients with familial hypophosphataemic vitamin D resistant osteomalacia and spinal cord compression are reported. Three of these patients were treated by decompressive laminectomy and each made a good recovery. At surgery new bone formation in the ligamentum flavum and thickening of laminae were found to be responsible for the canal stenosis and cord compression. Two of these four patients, and 10 others were examined by computed tomography to determine the incidence, site and extent of any intra-spinal new bone formation. Facet joint hypertrophy and thickened laminae were observed at some level in all the patients, but much the most important cause of spinal canal stenosis was new bone formation in the ligamentum flavum, in the mid and lower thoracic spine, occurring at several, but mainly contiguous vertebral levels. Severe spinal canal stenosis was found in eight of the 12 patients scanned. No obvious relation was found between the presence of intra-spinal new bone formation and the clinical severity of the disease or the presence of extra-skeletal ossification in para-spinal and other sites. Computed tomography offers a simple, non-invasive technique for identifying those patients at risk of cord compression from new bone formation.

Female↗
PubMed1986

The osteodystrophy of hypervitaminosis D: a metabolic study.

A patient received 2.5 mg vitamin D2 daily for 10 years and presented with increasing skeletal pain and hypercalcaemia. The limbs were painful to touch especially at the insertions of ligaments and tendons, and radiographs showed osteosclerosis with calcification in the periosteum, blood vessels, tendoachilles and plantar fascia. Bone histomorphometry showed increased amounts of osteoid and defective mineralisation despite hypercalcaemia, hyperphosphataemia and raised serum concentrations of vitamin D metabolites. A negative external calcium balance was documented in the presence of enhanced intestinal calcium absorption and an increase in urinary hydroxyproline excretion. Cortisone improved calcium balance and corrected the hypercalcaemia by reducing serum 1,25-dihydroxyvitamin D levels and urinary hydroxyproline excretion.

Bone and Bones↗
PubMed1985

Computers and veterinary practice in the United Kingdom.

The results of a survey of 103 computers being used by veterinary surgeons in the United Kingdom are presented. Details of the hardware and software in use are given as well as the costs, time taken to change to computerisation and the ease of implementing such a changeover. The problems that arose with hardware, software, supply companies and staff are summarised. Details are presented about after sales service contracts, office staff training, user opinions as to overall cost effectiveness, and advice offered to colleagues considering changing to computerisation.

Computers↗
PubMed1985

Abnormal vitamin D metabolism in Hodgkin's lymphoma.

In the autumn of 1984 there was spontaneous correction of hypercalcaemia in a patient with Hodgkin's lymphoma. Hypercalcaemia recurred when ultraviolet radiation (UVR) was given and this abnormality was associated with high serum concentrations of 1,25-dihydroxyvitamin D3 (1,25[OH]2D3) although concentrations of precursor 25-hydroxyvitamin D3 were normal. Chemotherapy of Hodgkin's lymphoma corrected the hypercalcaemia and subsequent exposure to UVR did not produce either hypercalcaemia or a high serum 1,25(OH)2D3. Rigorous tests were applied to the putative 1,25(OH)2D3 produced during hypercalcaemia and it was not possible to separate this metabolite from 1,25(OH)2D3 itself. It is concluded that the hypercalcaemia was caused by abnormal vitamin D metabolism which was a result of the Hodgkin's lymphoma. Hodgkin's tissue may have been the site of excessive synthesis of 1,25(OH)2D3.

Calcifediol↗
PubMed1985

An ELISA for the detection of maternal anti-trophoblast antibodies in human pregnancy.

An ELISA has been developed which is able to detect antibodies directed against determinants present on the plasma membrane of the outer layer, the syncytiotrophoblast, of term placentae. The IgG and IgM anti-trophoblast antibodies are present in the sera of women during the course of a normal pregnancy. The ELISA was based on the use of syncytiotrophoblast plasma membranes as the antigenic targets and utilised a developing antiserum conjugated to the bacterial enzyme urease. Although the assay was simple and reproducible, its viability was dependent on several factors including the stability of the antibodies and the proper preparative techniques for the production of the plasma membranes. Failure to adhere to the correct procedures resulted in an inferior non-viable assay.

Albumins↗
PubMed1985

Psychosocial functioning in prepubertal major depressive disorders. I. Interpersonal relationships during the depressive episode.

Psychosocial environment and relationships with parents, peers, and siblings of 115 prepubertal children were measured by interview with their parent(s) for the three-month period preceding the assessment. The children had a current diagnosis of major depression (52 children) or nondepressed neurotic disorder (23) or were assessed to be normal (40). Most aspects of psychosocial relationships were found to be significantly impaired in the psychiatric groups. This impairment was generally worse in the depressives and significantly worse for aspects of verbal and affective communication with parents and siblings. Prepubertal children with major depressive disorder regularly present social relation deficits in which two components can be distinguished: one general to childhood psychiatric disorder and another specific to major depression.

Age Factors↗
PubMed1985

Psychosocial functioning in prepubertal major depressive disorders. II. Interpersonal relationships after sustained recovery from affective episode.

Psychosocial relationships with parents, peers, and siblings, as well as school functioning, were measured at two points in time by parental interview in 21 prepubertal children: during an episode of major depression and after they had sustained an affective recovery from the index episode for at least four months. School functioning was completely normalized, but deficits in the child's intrafamilial and extra-familial relationships had improved only partially. The pattern of improvement was merely quantitative. Moderate deficits during the depressive episode reached, after affective recovery, the level of the normal control group. In contrast, severe deficits only improved to a moderate level of severity. It is suggested that treating the affective disorder is not sufficient in many children with major depression and that efficacy studies of psychotherapeutic interventions in affectively recovered children are needed.

Achievement↗
PubMed1985

The assessment of affective disorders in children and adolescents by semistructured interview. Test-retest reliability of the schedule for affective disorders and schizophrenia for school-age children, present episode version.

The reliability of assessment of Research Diagnostic Criteria and DSM-III axis I affective disorders in children and adolescents was studied using a semistructured diagnostic interview. The Schedule for Affective Disorders and Schizophrenia (SADS) for School-Age Children (Kiddie SADS) Present Episode Version, an adaptation of the adult SADS for children was used. Fifty-two subjects, aged 6 through 17 years, were interviewed in a test-retest format by one of three pairs of interviewers. Assessment of symptoms and composite scales of the depressive syndrome were determined to have acceptable reliability, as were three depressive diagnoses. Conduct disorder was assessed with high reliability. Four anxiety disorders and their composite symptoms were assessed with unacceptable reliability; only separation anxiety was assessed with acceptable reliability. The results of this study showed generally lower reliability of symptoms, scales, and diagnoses than did two studies of adults using the SADS.

Adolescent↗
PubMed1985

A model of intervention in child-abusing families: a wider systems view.

This paper describes the application of some principles, taken from the modern psychotherapies by a therapeutic team, to the assessment and treatment of serious child abuse. Factors and dilemmas identified from the assessment and decision-making process are outlined, with particular reference to the roles of the various statutory and community agencies involved with such families. The paper demonstrates the ways in which the range of community and professional agencies may play a pathological role, unintentionally contributing to and maintaining child-abusing dynamics in families. The significance of dangerous unintended consequences of well-meaning agency interventions and of covert interagency activities are stressed.

Child↗
PubMed1985

Anti-trophoblast antibody responses during normal human pregnancy.

During the course of a normal uncomplicated human pregnancy the mother generates an antibody response directed against determinants present on the plasma membrane of the outer fetal layer of the term placenta, the syncytiotrophoblast. The response, measured by an ELISA that utilises syncytiotrophoblast plasma membrane as the antigenic target, is predominantly IgG in nature, but with a minor contribution from IgM molecules. Maximum responses were observed during the first trimester and the levels gradually declined as the pregnancy progressed. On a population basis, this antibody response profile was mainly restricted to first and second pregnancies, although anti-trophoblast antibody responses could be detected in multiparous women but with a greatly reduced incidence compared with primipara. Mechanisms to account for these observations are discussed. Throughout, the anti-trophoblast antibody levels detected in pregnancy sera were compared with the background levels which were observed in sera obtained from males and nulliparous non-pregnant females.

Antibody Specificity↗
PubMed1985

Identification of selectively solubilised syncytiotrophoblast plasma membrane proteins as potential antigenic targets during normal human pregnancy.

Syncytiotrophoblast plasma membranes prepared from term placentae were selectively solubilised in non-ionic detergents. The solubilised proteins and the insoluble residue were tested in an ELISA assay for their ability to function as antigenic targets for anti-trophoblast antibodies present in normal first trimester pregnancy sera. The soluble proteins were fractionated by gel filtration and four major antigen forms were identified. The antigens were reactive with affinity purified anti-trophoblast antibody isolated from maternal sera and hence were termed maternally-recognised trophoblast antigens (MRTA); these were designated MRTA-I (Mr = 400,000 D), MRTA-II (Mr = 142,000), MRTA-III (Mr = 50,000) and MRTA-IV (Mr = 13,000). The relationship between MRTA-I, II, III and IV and antigens identified in maternal sera in the form of immune complexes is discussed.

Antibody Specificity↗
PubMed1985

The formation of immune complexes in primiparous and multiparous human pregnancies.

Using a recently developed ELISA, antibodies were detected in maternal sera with reactivity directed against determinants present on the plasma membrane of the outer layer of the placenta, the syncytiotrophoblast. The anti-trophoblast antibodies were present in maternal sera in the form of "free" antibodies and "immune complex" antibodies. Examination of the sera throughout gestation and from successive pregnancies revealed that the generation of anti-trophoblast antibodies and the formation of immune complexes was predominantly a first pregnancy and early second pregnancy event, with very little activity detectable in later pregnancies. It is proposed that immune recognition occurs in a first pregnancy, which generates some form of immunosuppression that involves the activation of suppressor memory cells.

Antigen-Antibody Complex↗