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Biomedical subjects

S Thomson

Publications and source records attributed to S Thomson.

At least 73 records · Page 4Linked to original sources
PubMed1989

A 125I-radioimmunoassay for measuring androstenedione in serum and in blood-spot samples from neonates.

We developed a radioimmunoassay with a gamma-emitting radioligand to measure androstenedione in human serum and in dried blood-spot samples from newborns. Antisera were raised in rabbits against androstenedione linked to bovine serum albumin at positions 3, 6, or 11 on the steroid nucleus. Radioligands were prepared by linking [125I]iodohistamine at positions 3, 6, or 11. Linkages were through either carboxymethyloxime or hemisuccinate bridges. All label and antibody combinations were examined, and the most sensitive and specific combination (antiserum raised against androstenedione-3-carboxymethyloxime-bovine serum albumin with an androstenedione-carboxymethyloxime-[125I]iodohistamine label) was selected for full evaluation. We report the performance of these selected reagents in an immunoassay for androstenedione in both serum and dried blood-spot samples from neonates. We measured concentrations of androstenedione in serum under normal and pathological conditions such as congenital adrenal hyperplasia and polycystic ovarian disease. Diurnal variation in normal men was observed. Androstenedione was measured in blood spots from neonates born at term or prematurely, with respiratory distress syndrome, or with congenital adrenal hyperplasia.

Adrenal Hyperplasia, Congenital↗
PubMed1987

Explosive anaesthetic agents. A regional survey on the use of ether and cyclopropane.

A total of 156 consultant anaesthetists in the North East Thames Regional Health Authority were circulated with a questionnaire on their personal use of ether and cyclopropane and their attitudes towards restriction or withdrawal of these agents: 144 completed questionnaires were received (92% response). Four anaesthetists (3%) claimed to use ether regularly at least once a month and 27 anaesthetists (19%) felt that their anaesthetic practice would suffer if ether were withdrawn. Cyclopropane had 62 regular users (43%) and 65 anaesthetists (45%) felt that their practice would suffer if it were withdrawn. Ninety-two anaesthetists (64%) were prepared to confine their use of explosive agents to either the anaesthetic room or the operating room; of these, three-quarters favoured the anaesthetic room. There were few notable differences in the pattern of use of explosive agents between anaesthetists with more than 21 years in the specialty and those with less than 21 years.

Anesthesia, Inhalation↗
PubMed1985

A new device for delayed hypersensitivity skin testing.

A new device for assessment of delayed cutaneous hypersensitivity using seven standardized antigens (Multitest CMI) was compared to conventional intradermal testing with two recall antigens in 83 patients referred for nutritional support. Sixteen patients (19.3%) were anergic to Multitest CMI while four (4.8%) were anergic to conventional testing. Patients anergic to Multitest CMI had a higher complication (intraabdominal abscess, prolonged ileus, sepsis, pneumonia) than those who were immunocompetent by this test suggesting a group at greater risk. This interpretation is consistent with an increased specificity of Multitest CMI over conventional testing in the identification of clinically important anergy.

Adult↗
PubMed1984

Evaluation of an automated image analysis system for counting human tumor colonies.

The Omnicon FAS II image analysis system was applied to counting tumor colonies grown in a soft agar human tumor clonogenic assay with a detailed protocol designed to assess the instrument's sensitivity, specificity, precision, and accuracy. Comparisons of technician and instrument counts were done on a blinded basis. Sensitivity studies (which used metal microspheres) yielded a correlation coefficient (r) of 0.999 between technicians and the counter. A field-by-field analysis of the instrument's specificity for identifying individual objects correctly as tumor colonies rather than artifacts (as identified by the technician) was excellent (r = 0.95). In the precision studies (determined with repeated automated counting of the same samples for five days), the median coefficient of variation was less than 7%. Accuracy was evaluated on cultures of fresh biopsies from 30 human cancers obtained for drug sensitivity testing as well as on a series of tumor cell lines. The correlation between the mean number of colonies counted by the technicians and by the colony counter was greater than 0.91. Similar comparisons of mean percent survival of tumor colony-forming cells after drug exposure between technician and machine were also quite acceptable (r = 0.85). We conclude that the colony counter provided sufficient reliability to be applied to counting human tumor colonies grown in vitro. In addition, the colony counter performed the Petri dish counts ten times faster than experienced technicians and without associated operator fatigue.

Animals↗
PubMed1984

Cephalometric evaluation of the changes in patients wearing complete dentures. A ten-year longitudinal study.

This study analyzed the longitudinal cephalometric head films of 37 edentulous patients over a 10-year period. The purpose of the investigation was to document changes within the craniofacial complex, residual ridge resorption, and position of the dentures. The changes were correlated with the following variables: age, sex, skeletal pattern, number of years edentulous, technique of denture fabrication, and nighttime wear of the dentures. Findings in this study suggest the following. The maxillae and the mandible showed sagittal spatial counterclockwise displacement. Complete dentures exhibit a counterclockwise rotation and forward movement. Soft tissue seating is more important than alveolar ridge resorption in the positional changes of complete dentures. Variation in denture techniques had no influence on the observed changes. Artificial porcelain teeth did not show a measurable amount of attrition during the 10-year observation period. Observed changes were not significantly affected by variables such as sex, years edentulous, nighttime wear, or skeletal pattern. Two exceptions were that the skeletal pattern affects prognathism and number of years edentulous affects mandibular ridge resorption.

Adult↗
PubMed1980

Autologous bone marrow transplantation in relapsed adult acute leukemia.

From March, 1976 to February, 1979, 28 cases of adult acute leukemia of which 24 were evaluable were treated in irreversible relapse with high dose chemotherapy (piperazinedione) and supra-lethal total body irradiation (TBI) in conjunction with autologous bone marrow transplantation (ABMT). The marrow cells grafted were collected and stored in liquid nitrogen at the time of remission. In 12 patients the marrow cells were fractionated using discontinuous albumin gradients in an attempt to separate normal cells from residual leukemic cells. Twelve patients achieved complete remission (CR); in 9 additional patients signs of engraftment were evident but death occurred before achievement of CR. Seven of 12 AML patients, which were treated with bone marrow transplantation as first treatment of their relapse, achieved CR. Four of 5 patients with ALL, whose bone marrows were collected during first remission, reached CR. The median CR duration was 4+ months and the median survival of the patients reaching CR was 6+ months. Autologous bone marrow transplantation offers a good chance of CR (66%) when marrow is collected during first remission and used as first treatment for AML in third relapse and ALL in second relapse.

Acute Disease↗
PubMed1979

Autologous bone marrow transplantation in relapsed adult acute leukemia.

From March, 1976 to February, 1979, 28 cases of adult acute leukemia of which 24 were evaluable were treated in irreversible relapse with high dose chemotherapy (piperazinedione) and supra-lethal total body irradiation (TBI) in conjunction with autologous bone marrow transplantation (ABMT). The marrow cells grafted were collected and stored in liquid nitrogen at the time of remission. In 12 patients the marrow cells were fractionated using discontinuous albumin gradients in an attempt to separate normal cells from residual leukemic cells. Twelve patients achieved complete remission (CR); in 9 additional patients signs of engraftment were evident but death occurred before achievement of CR. Seven of 12 AML patients, which were treated with bone marrow transplantation as first treatment of their relapse, achieved CR. Four of 5 patients with ALL, whose bone marrows were collected during first remission, reached CR. The median CR duration was 4+ months and the median survival of the patients reaching CR was 6+ months. Autologous bone marrow transplantation offers a good chance of CR (66%), when marrow is collected during first remission and used as first treatment for AML in third relapse and ALL in second relapse.

Adolescent↗
PubMed1975

Comparison of polysaccharides produced by Myxococcus strains.

Exopolysaccharides were prepared from cultures of four Myxococcus strains grown on solid and in liquid media, and also from the fruiting bodies. Lipopolysaccharides could be extracted with aqueous phenol from the vegetative bacteria, but were absent from microcysts. Mannose and D-glucose were present in all the exopolysaccharides and three of the lipopolysaccharides examined. Other monosaccharides identified in the exopolysaccharides were D-galactose, N-acetylglucosamine and N-acetylgalactosamine. The composition of the lipopolysaccharides was more complex than that of the exopolysaccharides and, in addition to the neutral hexoses and amino sugars, rhamnose was identified in two preparations and ribose in another. No lipopolysaccharide preparations contained O-methyl xylose or heptose. The polysaccharides secreted by the bacillary forms grown on solid or in liquid media closely resembled the polysaccharides isolated from the fruiting bodies, in which they provided a matrix surrounding the microcysts. Each pair of polysaccharides contained the same monosaccharides, although in slightly different proportions. Differences were found in preparations from different strains. These results suggest that in the development cycle of the genus Myxococcus, considerable use is made of pre-existing enzyme systems to synthesize the precursors necessary for polysaccharide synthesis. Any specific difference between the polysaccharide produced by the bacilli and that surrounding the microcysts may lie in the fine structure, rather than in the individual components.

Acetylgalactosamine↗
PubMed1975

Coagulation studies in ulcerative colitis and Crohn's disease.

Thromboembolic disease is a known complication of ulcerative colitis, but is rarely reported in Crohn's disease. In this study, we have tried to determine if there are indeed coagulation abnormalities associated with these two diseases. Four groups of patients were studies: (1) patients with ulcerative colitis; (2) patients with Crohn's disease; (3) patients with other diseases; (4) healthy control subjects. In both disease groups, platelet counts, factor V, factor VIII, and fibrinogen levels were found to be elevated, while antithrombin III levels were decreased.

Adolescent↗