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Biomedical subjects

B M Smith

Publications and source records attributed to B M Smith.

At least 91 records · Page 5Linked to original sources
PubMed1982

Increasing participation and improving the quality of discussions in seventh-grade social studies classes.

An experiment was conducted to evaluate procedures to improve classroom discussions in seventh-grade social studies classes. An increased number of students participated in discussions when rules were stated for discussions, students were praised for their contributions, the teacher restated or paraphrased students' contributions aloud or on the blackboard, the teacher planned an outline of discussion questions, student contributions to discussions were recorded and were used to determine part of the students' grades for the class, and discussion grades were publicly posted.The second part of the study focused on procedures designed to improve quality of classroom discussions. Students were taught to participate in discussions by providing reasons for their statements, comparisons between different points, or examples supporting their statements. As each type of contribution was taught, recorded, and counted toward part of the students' classroom grades, each type of contribution increased. Ratings of discussions by outside judges consisting of junior high school teachers, junior high school students, and persons experienced in conducting discussions, indicated that the training increased the overall quality of the discussions. Use of the quality training procedures, however, resulted in decreased levels of overall participation in discussion, a decrease that was reversed by the use of a group contingency for participation. Finally, the discussions after training seemed to be preferred by both the teacher and the students.

Journal Article↗
PubMed1982

Obturator foramen grafts: the preferable alternate route?

Although the femoral canal is the standard entrance route for vascular grafts to the lower extremity, several situations may arise that preclude the use of this route. In these circumstances an alternate pathway for revascularization is required. Experience in our center with the use of obturator foramen grafts for revascularization of nine limbs in eight patients is reported and underscores the value of this pathway as an alternative route for limb revascularization. The obturator foramen was employed to circumvent an infected arterial prosthesis at the groin level in seven patients (eight limbs) from 12 days to 4.5 years after the initial vascular procedure. The organisms responsible for graft infection included Staphylococcus aureus, Enterobacter cloacae, and Bacteroides fragilis. The final patient required iliac to superficial femoral artery bypass via the obturator foramen to manage occlusion and autolysis of the femoral artery by a mycotic embolus containing beta-hemolytic Streptococcus. Graft material used for these remedial procedures, included saphenous vein (three), Gore-Tex (three), and Dacron (three). Revascularization was satisfactory in each case. Each groin infection healed. Two patients died of unrelated causes at 1.5 and 5 months after operation. The seven remaining grafts at risk (six patients) remained patent 12 months in each case. Four grafts were doing well at 18, 36, 50, and 52 months. Three grafts failed at 13, 19, and 28 months; one was revised successfully, one was re-done and failed again. Obturator foramen bypass grafting provides satisfactory and durable revascularization when an alternate route to the lower extremity is required.

Adult↗
PubMed1981

Renovascular hypertension: anatomic and renal function changes during drug therapy.

Serial renal function studies were performed on 41 patients wtih renovascular hypertension (RVH) secondary to atherosclerotic renal artery disease who had been randomly selected for nonoperative management. In 19 patients, serum creatinine levels increased between 25% and 120%. The glomerular filtration rates dropped between 25% and 50% in 12 patients. Fourteen patients (37%) lost more than 10% of renal length. In four patients (12%), a significant stenosis progressed to total occlusion. Seventeen patients (41%) had deterioration of renal function or loss of renal size that led to operation. One patient required removal of a previously reconstructible kidney. Of the 17 patients with deterioration, 15 had acceptable blood pressure (BP) control during the period of nonoperative observation. Progressive deterioration of renal function in nonoperatively treated patients with atherosclerotic renal artery stenosis and RVH is common, and occurs even in the presence of BP control with drugs.

Adult↗
PubMed1981

Unaltered lymphocyte beta-adrenoceptor responsiveness in hyperthyroidism and hypothyroidism.

Beta adrenoceptor sensitivity may be altered in thyrotoxicosis and myxedema. We therefore studied beta-adrenoceptor responses of peripheral blood lymphocytes to stimulation with 10(-9) to 10(-6) M (-)-isoproterenol from patients before and after treatment of myxedema and thyrotoxicosis as well as in patients without thyroid disease. There were six patients in each group. Lymphocyte basal cyclic adenosine monophosphate (cAMP) concentrations were higher in untreated thyrotoxicosis (4.94 +/- 0.46 pmole/10(6) cells) than in controls (3.47 +/- 0.42 pmole/10(6) cells, p less than 0.05) and in untreated myxedema (3.11 +/- 0.50 pmole/10(6) cells, p less than 0.025). The full isoproterenol dose-response curves were similar in all groups. Calculated maximum velocity (Vmax) showed an approximate increase in cAMP of 14.5 pmole/10(6) cells. Isoproterenol concentrations at half-maximum velocity (EC50) were approximately 10(-8) M. It is concluded that lymphocyte beta 2-adrenoceptor responses are not altered in hypothyroidism and hyperthyroidism.

Adult↗
PubMed1980

DNA nucleotidylexotransferase of normal persons and leukemic patients.

We describe a relatively simple and rapid assay for DNA nucleotidylexotransferase (EC 2.7.7.31) activity in normal lymphocytes and leukemic cells from blood and (or) bone marrow of patients with various types of leukemia. We followed the method of Beutler and Kuhl (Am. J. Clin. Pathol. 70: 733, 1978) but separated the product of the reaction by precipitation on filter-paper disks instead of by centrifugation. Normal lymphocytes had a mean activity of 13.5 (SD = 9.21; range 3 to 35) pU/10(8) cells. Leukemic cells from the peripheral blood of patients with acute myelogenous leukemia had a mean activity slightly greater than normal (48 pU/10(8) cells); those from patients with acute lymphoblastic leukemia had a mean activity of 863 pU/10(8) cells, or 62-fold the normal mean. Similarly, cells from patients with chronic myelogenous leukemia in acute phase had a normal activity when the cell proliferation was myelogenous, but much higher activities when the cell proliferation was lymphoblastic. Cells from patients with chronic lymphocytic leukemia had normal activity. In leukemic patients, approximately similar results were obtained with cells isolated from bone marrow.

Bone Marrow↗
PubMed1979

Central nervous system changes complicating the use of radiotherapy for the treatment of a nasopharyngeal neoplasm in a diabetic patient.

A case is reported of a diabetic patient with a nasopharyngeal neoplasm who developed radiation induced brainstem damage even though irradiated at a conventional time-dose-volume relationship. The clinical course was correlated with autopsy findings which revealed radiation changes in the brainstem consisting primarily of vascular hyalinization with foci of infarction, edema, and demyelination. Atherosclerotic changes were conspicuously absent and therefore not the case of the alterations. The changes occurred three months after completion of therapy, which was more rapid than expected for radiation injury. It is hypothesized that diabetes may have predisposed the patient to this severe complication of standard therapy. More needs to be learned concerning the relationship between diabetes mellitus and radiation complications. Perhaps a modified time-dose relationship should be considered.

Adult↗
PubMed1979

Blood transfusion and renal transplantation.

Blood transfusions given to potential renal transplant recipients are beneficial to subsequent graft survival. This study has shown an association graft survival. This study has shown an association between the inhibitory activity of patients' plasma on their own non-specific lymphocyte responses to antigen and the administration of blood transfusions. Most of the inhibitory activity was related to alpha-2 macroglobulin. Alpha-2 macroglobulin was able to prolong the survival of rat cardiac allografts. Immunoregulatory activity related to the alpha globulins of plasma has been described in a wide variety of conditions (i.e. cancer, pregnancy, diabetes) and this study has shown similar activity following blood transfusions.

Animals↗
PubMed1978

A gated, high voltage iontophoresis system with accurate current monitoring.

A circuit description for a multichannel constant current source for microiontophoresis is presented. The circuitry allows a high voltage compliance, accurate monitoring of ionotophoretic current without use of batteries, and automatic current neutralization. Drugs may be applied either manually or with an external digital gate signal. A monitor to detect current unbalance greater than a preselected level is also included.

Iontophoresis↗
PubMed1977

Erythrocyte-UFA (Eufa) mobility test for multiple sclerosis: implications for pathogenesis and handling of the disease.

Erythrocytes from patients with Multiple Sclerosis (MS) show a highly significant reduction in their absolute electrophoretic mobility in the presence of linoleic and arachidonic acids (LA; AA). Patients with other (destructive) neurological disease (OND) and normal subjects show an increased absolute mobility of their erythrocytes in the presence of LA and AA. About 40 per cent of blood relatives of MS patients show an intermediate type of reaction - being slowed by LA and speeded up by AA. Administration of LA (or gamma linolenate) to an MS patient for some months leads to change in the mobilities from the MS to normal type, the AA result altering first. The effect of LA and AA on the absolute mobility of RBC may thus be used as a simple laboratory test involving a long established technique and eliminating the animal and other needs of the macrophage electrophoretic mobility (MEM) test. The implications of these findings for our understanding and handling of MS are briefly discussed.

Arachidonic Acids↗
PubMed1977

Characteristics of chick cerebral beta-adrenoceptors assessed by cyclic adenosine 3',5' monophosphate formation and [3H]-propranolol binding.

Chick cerebral beta-adrenoceptors have been characterised by measurement of cyclic AMP accumulation in brain slices and assessment of the specific binding of [3H]-propranolol to cerebral membranes. The binding of [3H]-propranolol was inhibited by beta-adrenoceptor agonists and antagonists with affinities that correlated well with their ability to stimulate cyclic AMP formation or to antagonise the cyclic nucleotide accumulation induced by isoprenaline. The relative potencies of a number of drugs in several cerebral regions suggests that the receptors may be of the beta2 subtype. Regional distribution studies revealed the highest density of binding sites in the cerebellum and lowest in the optic lobes. However, the concentration of [3H]-propranolol that produced half-maximal specific binding was similar in all regions. Subcellular fractionation of cerebral hemisphere tissue demonstrated an enrichment of [3H]-propranolol binding sites in the synaptosomal and microsomal fractions. There are discrepancies between the topographical distribution of beta-adrenoceptor binding sites and the endogenous noradrenaline level in chick brain and between the number of binding sites and the intrinsic activity of beta-adrenoceptor mediated cyclic AMP formation.

Adrenergic beta-Agonists↗