Search PubMed⌕ Search

Biomedical subjects

R Davis

Publications and source records attributed to R Davis.

At least 379 records · Page 21Linked to original sources
PubMed1986

Use of surface marker analysis to predict outcome of adult acute myeloblastic leukemia.

In order to investigate the clinical significance of surface antigen analysis in acute myeloblastic leukemia (AML), the blasts from 196 patients with AML were analyzed prospectively with a panel of 16 monoclonal antibodies. The antibodies were selected to identify differentiation-associated antigens of either the myeloid lineage (MY9, PM-81, AML-2-23, MY7, MCS-1, MY8, Mo1, MY1, MY4, Mo2), T cell lineage (T101, T11), B cell lineage (B1, B4) or multiple lineages [J5 (CALLA), HLA-DR]. Independent morphological review and classification by French-American-British (FAB) criteria was performed in 161 of the 196 cases. One or more myeloid surface antigens were detected on the blasts of 195 cases, while B and T cell markers were detected on 0% to 2% of cases. When both blood and marrow samples were studied on the same patient, very few differences were noted between the antigenic profiles of the paired specimens. The frequency of expression of individual myeloid antigens ranged from 91% (PM-81) to 29% (Mo2). Expression of individual antigens was found to correlate significantly with several clinical parameters including FAB classification, cytochemical staining for alpha naphthyl acetate esterase, leukocyte count, and the presence of extramedullary disease at presentation. Two myeloid antigens (MY4 and MY7) predicted for a low rate of complete remission (CR) to standard induction chemotherapy. MY4+ cases (37% of the total population) had a CR rate of 53%, while M4- cases had a CR rate of 69% (P = .03). MY7+ cases (57% of the total population) had a CR rate of 55% while MY7- cases had a CR rate of 73% (P = .01). Neither MY4 nor MY7 antigen expression was correlated with patient age. Paired combinations of antigens were also examined. The [MY4- MY7-] phenotype was exhibited by 32% of all cases and was associated with an 82% CR rate while the CR rate of all other cases was 54% (P = .001). The expression of three antigens (HLA-DR, MY8, Mo1) was associated with a decreased continuous complete remission (P less than .05, median follow-up time of 19 months). Expression of MY8 antigen was also associated with decreased survival (P = .03). These results confirm earlier reports of antigenic heterogeneity in AML, and indicate that immunologically defined subgroups of AML patients which are of potential clinical significance can be identified.

Antibodies, Monoclonal↗
PubMed1986

The effects of glucagon and metoclopramide as measured by the electrogastrogram.

The electrogastrogram, purportedly a measurement of the stomach's electrical activity, has received increased attention recently. This attention has also created skepticism because measurements are taken from the cutaneous surface. To test the electrogastrogram's ability to measure the stomach's electrical potential, we infused glucagon (0.5 mg), metoclopramide (10 and 20 mg in two sittings), and a placebo into six subjects. The electrogastrogram registered predictable changes in response to these infusions. We conclude that the electrogastrogram measures the stomach's electrical activity. Additionally, the unique data gathered by the electrogastrogram suggest that glucagon and metoclopramide both act directly on the electrical activity of gastric cells.

Double-Blind Method↗
PubMed1985

Modulation of type alpha transforming growth factor receptors by a phorbol ester tumor promoter.

Epidermal growth factor (EGF) and an EGF-like transforming growth factor (eTGF) from retrovirally transformed cells bind to a common receptor type in A431 cells. We have investigated the effects of the tumor promoter phorbol myristate acetate [PMA] on EGF/eTGF receptors in intact A431 cells. Treatment with PMA at 37 degrees C induces a complete loss of high-affinity (Kd = 35-50 pM) binding sites for eTGF and EGF on the cell surface of A431 cells. This effect is half-maximal at 0.1 nM PMA, exhibits rapid kinetics, and persists for at least 4 hr in the presence of PMA. eTGF and PMA added to intact A431 cells induce the phosphorylation of immunoprecipitable 170kd EGF/eTGF receptors. The EGF/eTGF receptor isolated from control cells was found to contain phosphoserine and phosphothreonine. PMA and eTGF caused a marked increase in the level of these two phosphoamino acids. In addition, eTGF but not PMA caused the appearance of phosphotyrosine in the EGF/eTGF receptor in vivo. We conclude that the tumor-promoting phorbol diester regulates both the affinity and phosphorylation state of the A431 cell receptor for the type alpha transforming growth factors, eTGF and EGF.

Animals↗
PubMed1985

Mood and food: an analysis of bulimic episodes.

The present study examined those factors which differentially lead to normal eating and binge eating. Twenty-one bulimic subjects and comparison subjects monitored their mood, hunger, and food intake hourly over a number of days. The bulimic sample ate fewer meals and had lower overall mood. Positive mood, food abstinence combined with intensified hunger, and being in the company of another person preceded normal eating (i.e. retained meal). Negative mood, recent consumption of food, and being alone preceded bulimic episodes.

Adult↗
PubMed1985

The prediction of relapse in bulimia nervosa.

Thirty-nine women successfully treated for bulimia nervosa were followed up six months after the conclusion of treatment and classified as maintaining recovery or partially or completely relapsed. Clinical and psychometric variables including body image disturbance and dissatisfaction were entered into regression equations to identify predictors of relapse. Dissatisfaction with body image at the end of treatment was the most potent predictor of relapse. The finding is interpreted as underscoring the importance of addressing issues of body image in therapy if treatment gains are to be maintained.

Adult↗
PubMed1985

Valproic acid clearance: unbound fraction and diurnal variation in young and elderly adults.

Six young (22 to 25 years old) and six elderly (60 to 88 years old) healthy adults took valproic acid, 250 mg by mouth, at 8 am and 8 pm for 5 days. On the fifth day, blood samples were drawn over each dosage interval. Both young and elderly subjects exhibited diurnal variability. Total and unbound clearances in the young and elderly subjects were about 10% and 15% higher during the evening. These changes led to lower total and unbound steady-state and peak concentrations during the nighttime dosage interval. There were no differences in total steady-state concentrations and kinetics computed from total concentrations between the young and elderly, but there were differences in unbound steady-state concentrations and kinetics. Unbound clearances were 65% lower, which resulted in unbound steady-state concentrations 67% higher in the elderly. The average unbound fractions in the elderly and young were 10.7% and 6.4%. To minimize the influence of diurnal variability, drug concentrations should be determined at the same time each day. Total valproic acid concentration data may be less useful in elderly patients; unbound concentrations may be more reliable in this population.

Adult↗
PubMed1985

Atropine serum concentrations after multiple inhaled doses of atropine sulfate.

Atropine may be given by inhalation for bronchodilation. Intravenous atropine at doses of 0.32 to 1 mg yields serum levels of 2 to 6 ng/ml, with an elimination t1/2 of about 4 hours. Efficient inhalation of large single doses leads to similar concentrations in some individuals, but under clinical conditions drug delivery may be less efficient. Of concern is accumulation of the drug in the body with multiple-dose therapy. We measured serum levels of atropine after single inhaled doses and again after 48 to 72 hours of inhalation every 4 to 6 hours in 11 subjects. The drug was administered by therapists at doses and techniques commonly used in the clinical setting. Serum concentrations of atropine were negligible after the first dose in all subjects but were detectable in six of nine subjects who received the drug for more than 48 hours. Three of the subjects had levels greater than 2 ng/ml.

Absorption↗
PubMed1985

Bioengineering changes in spastic cerebral palsy groups following cerebellar stimulation.

Quantitative bioengineering tests were performed on 30 spastic cerebral palsy (CP) patients who underwent chronic cerebellar stimulation (CCS) using the fully implantable pulse generator (Neurolith 601, 1.1-1.8 microC/cm2/phase). Using respiratory inductive plethysmography to measure 8 patients with paroxysmal and/or ataxic breathing patterns, 5 were shown to revert to normal with 3 others markedly improved within 5 months of CCS. Compliance testing of the ankle was performed on 4 patients who showed improvement in 9 of the 16 tests performed. Motor performance ability was evaluated with 9 comprehensive tests in 17 patients. Following 1-2 weeks of CCS, 52% showed performance increases greater than 10%, increasing to 62% during the first year.

Cerebellum↗
PubMed1985

State of education.

Explore the source record for details and available documents.

Dental Technicians↗
PubMed1984

Artificial ventilation for cardiopulmonary resuscitation.

The ability of 100 members of the nursing staff to administer artificial ventilation was tested on a manikin. Six techniques of artificial ventilation were used. A minimum minute volume of 6 L was chosen as the criterion for adequate ventilation. Eighty-eight per cent of nurses "passed" using mouth-to-mouth ventilation, 66% "passed" using mouth-to-face-mask, 55% "passed" using the RM-1 injector system, 52% "passed" using the Mistviva injector system, while very low "pass" rates of 25% and 15% were obtained with the Air-Viva and Mapleson B circuits, respectively. It was concluded that mouth-to-mouth technique was the best form of ventilatory support provided by the nursing staff tested in this trial. In general, the use of mask systems should be restricted to highly trained staff members who have demonstrated continuing proficiency.

Australia↗
PubMed1984

Autonomic correlates of the subjective anxiety scale.

The subjective anxiety scale is an assessment tool commonly used in behavioral research and therapy to quantify verbal report of private events, usually states of fear. An investigation was undertaken to determine the extent of relationship between the subjective anxiety scale and two concurrent measures of autonomic arousal, peripheral vasoconstriction and heart rate. Measures were recorded during baseline, surgical film and second baseline phases for 20 subjects. The subjective and autonomic measures indicated increased anxiety during the film phase and significant correlations were found between subjective report of anxiety and the two physiological indices. The results support the continued use of the subjective anxiety scale as a clinical assessment tool. Practice and research implications are discussed.

Adult↗
PubMed1984

Pulmonary cytology in chrysotile asbestos workers.

The prevalence of atypical cytology has been determined in relation to age, smoking and asbestos exposure for male workers employed in 3 mines in the Province of Quebec. Overall participation was 71%. Out of 867 participating workers, 626 (72%) presented a deep cough specimen within normal limits, 74 (8.5%) a specimen with mild atypical metaplasia and 10 (1.2%) a specimen with moderate atypical metaplasia. Four lung carcinoma were identified. Five percent of the workers initially interviewed did not return their specimen and 12.7% had unsatisfactory test results. Proportions of cellular atypia increased with age and asbestos exposure. Using logistic regression analysis, estimated probabilities of abnormal cytology for workers aged 25 years when started mining increased with both years of asbestos exposure and exposure index measured in fibres per cubic centimeter.

Adult↗
PubMed1984

Mixed beam radiation therapy for unresectable squamous cell carcinomas of the head and neck: the results of a randomized RTOG study.

Three hundred and twenty-two patients with inoperable squamous cell carcinomas of the head and neck were entered on a randomized study comparing "mixed beam" radiation therapy with photon radiation therapy. Patients with histologically proven tumors of T-stage T2, T3, or T4 and any N-stage originating in the oral cavity, oropharynx, supraglottic larynx, or hypopharynx were eligible. One hundred forty-five patients were randomized to photon treatment and 177 were randomized to mixed beam treatment. No significant differences could be demonstrated between the experimental and control groups for primary tumor control or overall survival, although there was an advantage for mixed beam treatment over photon treatment for patients with metastatic cervical adenopathy (69 vs. 55% complete response rate in the nodes, p = .024). It is concluded that mixed beam radiation therapy does not offer a significant advantage over photon radiation therapy for patients with advanced squamous cell carcinomas of the head and neck.

Aged↗
PubMed1984

Fast neutron radiation therapy for unresectable squamous cell carcinomas of the head and neck: the results of a randomized RTOG study.

Forty patients with advanced, unresectable squamous cell carcinomas of the head and neck were entered on a prospective, randomized study comparing fast neutron radiation therapy with conventional photon radiation therapy. Twenty-six patients were randomized to neutrons, and 14 patients were randomized to photons. The randomization was purposefully unbalanced in favor of the experimental treatment. The complete response rate for the neutron-treated group of patients was 52%. The complete response rate for the photon-treated group of patients was 17%. The difference is statistically significant at the p = .04 level. The two-year survival rates for the neutron-treated group and the photon-treated group were 25 and 0%, respectively. The major complication rates were not statistically significantly different for the two groups (18% for neutrons, and 33% for photons).

Aged↗
PubMed1984

Diurnal variation in valproic acid clearance.

Diurnal variation in total and unbound valproic acid concentrations was measured at steady state in seven healthy men and three healthy women after 250-mg oral doses every 12 hr. Total average steady-state concentration (Css) during the morning dosage interval was 50.4 mg/l. During the evening dosage interval, total Css was 45.7 mg/l. Unbound Css was also less during the evening (2.9 and 3.4 mg/l). These changes were due to higher total and unbound clearance rates during the evening dosage interval. Total peak concentrations were lower (56.8 and 64.3 mg/l) and time of peak concentrations slightly longer (2.2 and 1.8 hr) during the evening. There was marked interindividual variability in all these changes. For best reproducibility of steady-state valproic acid concentrations, our results suggest that total and unbound levels be drawn at the same time of day.

Administration, Oral↗