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Biomedical subjects

J Smith

Publications and source records attributed to J Smith.

At least 847 records · Page 47Linked to original sources
PubMed1991

Applying the interaction design approach to medical devices.

The medical industry is undergoing a radical transformation as increasingly powerful personal computers become the predominant user interface for both clinical and laboratory equipment. Accompanying this change is the introduction of a design discipline known as interaction design, which has given rise to a new breed of specialists whose role is to champion the end user--that is, the physician, scientist, or medical technician--at every stage of the product-development cycle.

Computers↗
PubMed1991

Collection and use of peripheral blood stem cells in very small children.

Collections of peripheral blood stem cells (PBSC) from children weighing less than 25 kg have been limited by concern about citrate toxicity. We developed a modified collection technique on the Fenwal CS3000 blood cell separator and used it in three children weighing 8.3, 20 and 24 kg with neuroblastoma involving the marrow. The saline prime was discarded as a mixture of 250 ml red cells, 100 ml fresh frozen plasma, and 100 ml 5% albumin was run into the separator. Heparin (1500 units/h) was used to supplement ACD, which was infused at a low rate (1:25-1:32 vs blood, vs the usual 1:13). No serious difficulties were encountered during or after the collections. A total of 5.7, 4.8 and 6.4 x 10(8) mononuclear cells/kg were collected in six procedures per patient. After cell cryopreservation and patient preparation using high-dose chemotherapy, the cells were thawed in 37 degrees C saline and infused without incident. Hematopoietic recovery was observed, and one of the patients remains in clinical remission after 11 months of follow-up. The addition to previously developed procedures of the use of partial albumin prime, low citrate anticoagulation, and heparin allows convenient and safe collection of PBSC in extremely small children, and these PBSC are effective.

Blood Component Removal↗
PubMed1991

Is the beneficial effect of sulfasalazine due to inhibition of synovial neovascularization?

Angiogenesis is fundamental to support the continued synovial proliferation observed in rheumatoid arthritis. We investigated the effects of sulfasalazine and its metabolites on endothelial cell proliferation, a prerequisite to angiogenesis. At concentrations achieved in vivo sulfapyridine inhibited basal and endothelial cell growth factor stimulated endothelial cell proliferation. Sulfasalazine and 5 amino salicylic acid had no effect.

Aminosalicylic Acids↗
PubMed1991

The effect of fructose on alcohol metabolism and on the [lactate]/[pyruvate] ratio in man.

Ten male subjects were given alcohol by intravenous infusion and maintained at a constant blood alcohol level. The rate of alcohol metabolism was measured before and after an oral dose of fructose (100 g), as the amount of alcohol required to maintain the steady state. The mean rate of alcohol metabolism increased by 80% after fructose but there was considerable variation among the subjects, which was related to their plasma fructose concentrations. Blood lactate increased after fructose to a greater degree than blood pyruvate, resulting in a significant increase in [lactate]/[pyruvate] ratio. Since fructose increased the [lactate]/[pyruvate] ratio when it increased alcohol metabolism, the action of fructose cannot be explained by a decrease in the liver cytoplasmic [NADH]/[NAD] ratio and some other mechanism must be sought.

Adolescent↗
PubMed1990

Endometrial biopsy technique and uterine pathologic findings in llamas.

Uterine tissue specimens from 90 llamas with history of infertility were examined and graded microscopically; 83 specimens were obtained by endometrial biopsy and 7 specimens were obtained at necropsy. Fifteen llamas (16.7%) had a normal uterus, which was graded 1A. Twenty-three llamas (25.6%) had minor uterine abnormalities that were graded 1B. Forty-five llamas (50.0%) had appreciable endometritis that was graded 2A. Three llamas (3.3%) had endometritis with gland fibrosis that was graded 2B. Two llamas (2.2%) had notable uterine gland fibrosis that was graded 3A. Two llamas (2.2%) had uterine neoplasia that was graded 3B. Thirty-six llamas had follow-up evaluation; 22 became pregnant, most after some form of treatment. Uterine biopsy in llamas was readily performed without complications and was valuable in identifying a wide range of uterine diseases, most of which were amenable to treatment.

Adenocarcinoma↗
PubMed1990

Circadian rhythmicity of rate-normalized QT interval in hypothyroidism and its significance for development of class III antiarrhythmic agents.

Lengthening of repolarization and refractoriness occurs in hypothyroidism; it is associated with a reduced probability of arrhythmias, with the converse occurring in hyperthyroidism. Because the QT interval and its circadian rhythmicity relative to heart rate is poorly defined in man, we used our new computer-assisted technique to measure QT interval in our analysis of 24-hour Holter tapes before and after (8 to 12 weeks) thyroxine (T4) replacement in 10 patients with hypothyroidism; the findings were compared to those in 6 normal control subjects. QTc interval was prolonged (p less than 0.02) and heart rate decreased (p less than 0.005) during the hypothyroid state. Data were analyzed for circadian rhythmicity by repeated-measures analysis. Circadian variation in QTc and heart rate was statistically significant during hypothyroid and euthyroid states (p less than 0.001) as well as in control subjects, but the circadian rhythmicity of QTc interval and heart rate were out of phase; the maximum prolongation of QTc occurred between midnight and 6 A.M., at a time when heart was at its lowest. QTc interval remained significantly prolonged after 8 to 12 weeks of T4 replacement, when biochemical indexes of hypothyroidism had returned to normal values. The computer-assisted QTc interval determination technique that we used, and our data on the circadian rhythmicity of QTc and heart rate, have significant implications for the development of new class III antiarrhythmic agents.

Adult↗
PubMed1990

Extrageniculate vision in hemianopic humans: saccade inhibition by signals in the blind field.

The functional competence of extrageniculate visual pathways in hemianopic humans was demonstrated by showing that distractor signals in the blind half of the visual field could inhibit saccades toward targets in the intact visual field. This inhibitory effect of unseen distractors in patients occurred only when distractors were presented in the temporal half of the visual field, was specific to oculomotor responses, and did not occur in normal subjects. These results show that a peripheral visual signal activates retinotectal pathways to prime the oculomotor system and that these pathways can mediate orienting behavior in hemianopic humans.

Analysis of Variance↗