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Biomedical subjects

D Davis

Publications and source records attributed to D Davis.

At least 289 records · Page 16Linked to original sources
PubMed1979

Atypical patterns of retrograde conduction over accessory atrioventricular pathways in the Wolff-Parkinson-White syndrome.

Patterns of ventriculoatrial conduction have been used to distinguish retrograde conduction over an accessory atrioventricular pathway from that over the normal atrioventricular conduction system. Ventriculoatrial conduction at a constant interval during incremental ventricular pacing and during progressive prematurity of ventricular extrastimuli has been considered characteristic of conduction over an accessory pathway. We describe three patients with the Wolff-Parkinson-White syndrome who had progressive or sudden increments in ventriculoatrial conduction over an accessory pathway during fixed-rate ventricular pacing or during introduction of ventricular extrastimuli. Such properties have been considered characteristic of conduction over the normal atrioventricular conduction system. We conclude that retrograde conduction over accessory pathways may resemble conduction over the normal atrioventricular conduction system.

Adult↗
PubMed1977

Predicting success in psychiatric training for foreign medical graduates: II. Patterns in course.

Faculty ratings of 22 foreign medical graduates ('FMGs'), all of whom entered psychiatric residency training at the University of Missouri-Columbia from 1966 through 1973, were compared with those of a similar group of North American medical graduates ('AMGs'). An on-going evaluation programme provided data for a variety of parameters ranging from 'theoretical knowledge' to 'clinical skills'. Results indicated that in most of performance the median FMG started at a level substantially lower than that of the median AMG and very slowly caught up. When achievement criteria were utilized it became apparent that, at least by the third year of training, 'superior' FMGs could equal or surpass the median performance of 'superior' AMGs, whereas 'marginal' residents, whether foreign or native-born, seldom attained even competence in most major spheres of functioning. Implications of these findings and those in related studies are discussed.

Clinical Competence↗
PubMed1977

Congenital anomaly of the odontoid in children. A report of four cases.

The embryologic origins of congenital abnormalities of the odontoid process are reviewed. Four cases of odontoid dysgenesis in childhood are presented. All of our cases were associated with a head injury, which subsequently led to the diagnosis. Pain was the most common presenting complaint in our patients. Decreased cervical mobility was the most consistent physcial finding. There was no major neurological defect implicating spinal cord compression in any of our patients. This is not true of adults with congenital abnormalities of the odontoid, particularly those with atlantoaxial instability. The diagnosis of odontoid dysgenesis is a radiographic one. Flexion-extension films, tomograms and cineradiograms are often required to make the diagnosis. C1-C2 subluxation, either anterior or posterior is often found. Prompt posterior cervical fusion is recommended as the treatment of choice.

Axis, Cervical Vertebra↗
PubMed1977

Amphetamine abuse.

Explore the source record for details and available documents.

Amphetamines↗
PubMed1975

Hyperlipoproteinemia in occlusive cerebrovascular disease.

The distribution of occlusive atherosclerotic lesions in the aortocranial circulation as determined by arteriography was correlated with results of plasma lipid and lipoprotein determinations of patients with symptoms and signs of cerebrovascular disease. The incidence of hyperlipoproteinemia in the total study population was 31.8%. The frequency of hyperlipoproteinemia was signigicantly higher in patients with atherosclerotic lesions limited to extracranial (51%) and intracranial major vessels (44.2%) when compared to the total number of patients and patients with only intracranial small-vessel disease (P less than .05). Type IV hyperlipoproteinemia was the most common abnormality (extracranial group, 42% type IV, 9% type II; intracranial major-vessel group, 35.8% type IV, 8.4% type II). Patients with intracranial small-vessel disease had the lowest frequency of hyperlipoproteinemia (14.2%). The frequency of hypertension with or without hyperlipoproteinemia was higher in patients with intracranial small-vessel disease (P less than .01).

Adult↗
PubMed1975

Myelination of brain in experimental hypothyroidism. An electron-microscopic and biochemical study of purified myelin isolates.

Myelin development has been studied in the neonatally hypothyroid rat brain by isolation and characterization of purified myelin preparations. The hormone deficiency results in a suppression of compact myelin formation and the persistence of a lighter possibly pro-myelin fraction. The appearance of myelin basic protein was markedly delayed in the hormone-deficient animals and this effect on the basic protein moiety may be responsible for the delayed myelinogenesis.

Animals↗
PubMed1975

Factors associated with attempted suicide among hospitalized depressed patients.

An attempt was made to identify background, sociodemographic and clinical variables which are associated with attempted suicide in depression. Within a sample of 308 depressed psychiatric inpatients, suicide attempters were younger than non-attempters and were identified by a pattern of chronic interpersonal maladjustment reflected clinically in withdrawal from social contact and the display of hostility or irritability toward others.

Adolescent↗
PubMed1973

Immunological studies in acute myeloid leukaemia: PHA responsiveness and serum inhibitory factors.

Sera from 16 of 20 patients with AML at some stage of the disease inhibited the in vitro PHA transformation of normal lymphocytes assessed by measuring the rate of DNA synthesis after 67-70 hours; 42% of pretreatment sera were inhibitory. Inhibitory activity was overcome at PHA concentrations 2-3 times greater than the concentration which allowed maximum discrimination between NHS and leukaemia sera.PHA transformation of washed lymphocytes obtained from AML patients before treatment and when receiving induction or consolidation (cytoreductive) chemotherapy was reduced only when cultures contained a high proportion of primitive cells. Even in primitive cell contaminated cultures significant responses to PHA could be measured if conditions were modified to prevent increasing acidity.Reports of reduced in vitro immunological reactions in pretreatment and poor prognosis patients may therefore be due to the presence of primitive cells in culture, and in treated patients to the failure of chemotherapy to reduce the circulating primitive cell count. Serum inhibitory factors may have a significant immunosuppressive effect in vivo, but the accurate assessment of the role of immune mechanisms in AML should attempt the measurement of specific immunity.

Culture Techniques↗