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Biomedical subjects

A Thompson

Publications and source records attributed to A Thompson.

At least 271 records · Page 15Linked to original sources
PubMed1985

Increase of oleic acid in erythrocytes associated with malignancies.

Total lipid extracts of erythrocyte cell membranes from 60 patients with documented malignancies, 41 patients with various acute and chronic diseases, and 40 healthy subjects were analysed. The results were expressed as ratios of stearic to oleic acid, reflecting the degree of desaturation of stearic acid. The mean ratios for the healthy subjects and controls without cancer were 1.5 (SD 0.27) and 1.45 (0.28), respectively, whereas the ratios for patients with malignancies were consistently lower than the cut off point of 1.0, with a mean of 0.69 (0.15) (p less than 0.001). The desaturation ratio was also significantly lower (p less than 0.001) in the group with recurrent tumours (mean 0.75 (0.04)) compared with those with no evidence of recurrent tumours (mean 1.55 (0.27)). It is suggested that the increased unsaturation (oleic acid) in the circulating erythrocytes may be useful in the diagnosis and postoperative monitoring of patients with cancer.

Erythrocyte Membrane↗
PubMed1985

What determines the symptoms associated with subclavian artery occlusive disease?

Symptoms associated with subclavian artery stenosis are related to reduced cerebral or arm blood flow. A large difference in blood pressure between the two arms is associated with symptoms of arm ischemia alone and is usually caused by an anatomic variant. The presence or absence of a radiologic steal alone did not seem to determine the type or presence of symptoms. The type of cerebral symptoms seems to be determined by the location of other extracranial vascular stenosis. In patients with hemispheric symptoms there was a higher incidence of anterior circulation insufficiency and a greater reduction in the overall cerebral blood flow. In patients with nonhemispheric symptoms a higher incidence of posterior circulation insufficiency occurred. There may be a small group with nonhemispheric symptoms and a subclavian artery stenosis in whom reversed vertebral artery blood flow is the sole determinant. Perhaps more accurate delineation of other extracranial vascular stenosis would help determine what stenosis in addition to the subclavian artery occlusive disease determines the presenting symptoms. Surgical repair of these lesions may lead to an improved cure rate in this group of patients.

Arm↗
PubMed1985

Reduction in the stearic to oleic acid ratio in human malignant liver neoplasms.

Total lipid extracts of liver tissue from 14 patients with primary and secondary liver tumours were analysed for relative values of saturation of 18 carbon chain length fatty acids (C18FA). The saturation indices (ratio C18S:C18u) of the tumour areas were significantly and consistently lower than the corresponding values in the non-tumour areas (P less than 0.001). It is proposed that the relative increase in unsaturated C18FA (oleic acid) could prove to be a chemical marker reflecting deficient cellular control of the desaturation of stearic acid.

Adult↗
PubMed1985

Reduction in the stearic to oleic acid ratio in the circulating red blood cells: a possible tumour marker in solid human neoplasms.

Gas liquid chromatography study of the 18 carbon chain length fatty acids (C18FA) of the human red blood cells (RBCs) was performed on 65 patients with various clinical disorders. It was found that the stearic to oleic acid ratio (SI) of the RBCs was significantly lower (P less than 0.001) in patients with malignant conditions (n = 20, SI = 0.62 +/- 0.16) compared with pathological non-malignant diseases (n = 10, SI = 1.19 +/- 0.2) and the normal control group (n = 35, SI = 1.57 +/- 0.5). Our early results suggest that the increased unsaturation (oleic acid) in the circulating RBCs could be used as a chemical marker in various solid neoplasms.

Chromatography, Gas↗
PubMed1984

A chemiluminescent probe specific for singlet oxygen.

We have synthesized a methoxyvinylpyrene (MVP) in order to model the mechanism for the observed microsomal chemiluminescence of benzo[a]pyrene 7,8-dihydrodiol, the proximate carcinogenic metabolite of benzo[a]pyrene. This MVP analog has been found to be a highly efficient and specific chemiluminescent probe for picomole quantities of singlet oxygen and singlet oxygen equivalents, and it produces significant chemiluminescence when reacted with cytochrome P-450 enzymes.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1984

Rapid expansion of human cytotoxic T cell clones: growth promotion by a heat-labile serum component and by various types of feeder cells.

Culture conditions are described that result in rapid expansion of cloned cytotoxic T cells of human origin. A combination of allogeneic lymphocytes and Epstein-Barr virus (EBV) transformed B cells (B-LCL) as irradiated feeder cells resulted in a 10-fold higher cell yield than obtained by use of either feeder cell alone. The large cell numbers obtained in a relatively short period of time facilitate in vitro and in vivo experimentation. Further enhancement of cell proliferation was obtained by the use of fresh human serum not heat-inactivated before use. This suggests the presence of a heat-labile growth stimulating factor or factors in human serum. Round-bottomed microtitre wells were found to give best culture results. Plating and harvesting of cells cultured in wells was facilitated by a specially designed culture flask. Addition of leucoagglutinin (purified phytohaemagglutinin) to the culture medium resulted in an approximately 3-fold higher cell yield. Optimal culture results were obtained when all the above factors were combined. It was possible to expand single cytotoxic T cells to up to 10(9) cells in about 30 days with full retention of cytolytic activity and target cell specificity. T cell clones have now been cultured for more than 70 generations.

B-Lymphocytes↗
PubMed1984

The effect of tamoxifen on the growth of human malignant melanoma in vitro.

The effect of tamoxifen on the growth of malignant melanoma was investigated using human cell lines and single-cell suspensions prepared from patients' tumours cultured in soft agar. Tamoxifen stimulated both [3H]-thymidine incorporation and cell numbers in all of the cell lines tested. Cytoplasmic oestrogen receptor (ER) was detected in one of the responding lines and progesterone receptor (PR) in another. Tumour colony formation in soft agar culture was satisfactorily established from tumour cell suspensions from 13 of 21 patients, only one of which had detectable cytoplasmic ER. Greater than 50% reduction in colony formation with 5 X 10(-7) M tamoxifen occurred in two tumours, neither of which contained ER. These results indicate that tamoxifen has the potential to either retard or accelerate the growth of human malignant melanoma.

Cell Count↗
PubMed1984

Two-dimensional gel analysis of a second family of class II molecules by polymorphic HLA-DR4,5, and w9 monoclonal antibodies.

Human Ia-like, class II molecules were isolated by immunoprecipitation with monoclonal antibodies from various HLA-D/DR homozygous cell lines and were analyzed by two-dimensional gel electrophoresis. The monoclonal antibody PLM12 reacted with B cells carrying DR4, DR5, DRw6.2, and DRw9 phenotypes, and its reactivity perfectly correlated with the previously defined TB21 (MB3-like) specificity. Class II molecules detected by PLM12 were structurally distinct from those precipitated by the anti-DR monoclonal antibody NC1 on all HLA-DR4, DR5, DRw6.2, and DRw9 homozygous cell lines and showed polymorphism in heavy and light chains among these cell lines. The monoclonal antibodies PLM2 and PLM9 only reacted with B cells carrying DR5 and DRw6.2 and also detected a distinct set of class II molecules from those precipitated by NC1 but identical to those of PLM12. Thus, PLM2 and PLM9 serologically detected a new subtypic antigen of the PLM12-reactive class II molecules. Furthermore, the antibody NC1 precipitated two light chains and one heavy chain from HLA-DRw6.2 homozygous cell line EBV-Sh. The result indicated the presence of three sets of class II molecules: two in a DR family and another carrying the polymorphic determinants detected by PLM2, PLM9, and PLM12 in a second family.

Animals↗
PubMed1983

Alpha gliadin antibody levels: a serological test for coeliac disease.

The diagnostic value in coeliac disease of circulating antibodies to casein, crude gliadin, and alpha gliadin was assessed using an adaption of the enzyme linked immunosorbent assay system. alpha Gliadin was the only antigen which consistently separated 26 patients with untreated coeliac disease from 26 normal controls and 13 patients with chronic inflammatory bowel disease. The mean assay index for the 26 patients was 3.1 (SD 1.2) compared with 1.05 (0.5) for the normal controls and 1.1 (0.6) for patients with chronic inflammatory bowel disease. The alpha gliadin antibody levels of six patients with coeliac disease who had maintained a gluten free diet for at least two years were not significantly higher than normal (1.0 (0.4)). The validity of the test was determined in 90 consecutive patients who were being investigated for the presence of coeliac disease. Levels of alpha gliadin antibody were raised in 36 out of 44 patients found to have histologically proved coeliac disease and in six out of 46 subjects whose jejunal mucosa was normal. Serial alpha gliadin concentrations were measured in 12 patients with coeliac disease who had repeat jejunal biopsies performed six months after starting a gluten free diet. The levels of antibody fell in seven of the eight patients whose jejunal mucosa improved on maintaining the diet. They remained raised in four patients who did not adhere to the diet and whose mucosa did not improve. Although a test measuring alpha gliadin antibodies is unlikely to replace jejunal biopsy in the diagnosis of coeliac disease it may be useful in screening for the disease among outpatients.

Antibodies↗
PubMed1983

A chemiluminescence assay specific for the microsomal metabolite, benzo[a]pyrene-7,8-dihydrodiol.

It is possible to assay for trans-7,8-dihydroxy 7,8-dihydrobenzo[a]-pyrene (BP-7,8-dihydrodiol) in complex metabolite mixtures produced during microsomal metabolism of benzo[a]pyrene (BP) because only the BP-7,8-dihydrodiol metabolite will produce significant chemiluminescence (CL) in the NaOCl-H2O2 singlet oxygen-generating system. The limiting CL sensitivity is 30 pmol in a 1-ml CL reaction mixture. CL assays for BP-7,8-dihydrodiol in microsomal reaction solutions gave concentrations identical with those determined by calibrated high-performance liquid chromatography.

Animals↗
PubMed1983

Definition of four HLA-A2 subtypes by CML typing and biochemical analysis.

The population of HLA-A2-positive individuals, currently considered serologically homogeneous, can be divided into three subtypes on the basis of antigen recognition by various HLA-A2-specific cytotoxic T lymphocytes (CTLs). When these three types of HLA-A2 antigens were analyzed biochemically, they were found to be distinct. Isoelectric focusing (IEF) of HLA antigens digested with neuraminidase (NANAse) suggested that the difference(s) reside in the polypeptide backbone of the HLA-A2 heavy chain. Biochemical analysis distinguishes three distinct categories of HLA-A2 antigens: (1) a major subtype, designated HLA-A2.I, (2) a minor subtype, designated HLA-A2.II, possessing a more basic isoelectric point (IEP) and (3) a minor HLA-A2 subtype more acidic in its IEP than HLA-A2.I, designated HLA-A2.III. A fourth HLA-A2 subtype could be defined by discordance between cell-mediated lympholysis (CML) typing and biochemical analysis. The latter HLA-A2 antigen was defined as a variant by CTL, but was biochemically indistinguishable from the major subtype HLA-A2.I.

Electrophoresis, Polyacrylamide Gel↗
PubMed1983

A robust, brief measure of an individual's most preferred level of salt in an ordinary foodstuff.

A single-session procedure to assess an individual's most preferred level of a factor in a product is justified theoretically and illustrated by the results for salt concentration in samples of bread and tomato soup tested on 30 young men who had had no previous experience of the task. Each man rated the saltiness of each sample as a distance below or above his ideal for that food type. Without the rater knowing, his stimulus set was coordinated to his rating responses in order to minimise biases in what other have shown can be a linear response mode. The Weber fraction is constant for the medium range of NaCl solutions when concentration units are used, and so Fechner's principle of direct scaling was applied: mean linear regressions between ideal-relative intensity responses and the logarithm of salt concentrations in each individual were nearly always statistically reliable with only six to 20 ratings of three to six salt levels in bread or soup. Values of the regression intercepts for bread at the initial session and five months later correlated significantly, as also did the regression slopes. Thus, a robust value for each individual's ideal salt level for each food could be interpolated from the regression equation. There was no effect of sequence of bread and soup sessions. Bread and soup salt-ideals were correlated, as were their slopes. A regression slope appears to represent an individual's tolerance of deviations from ideal. The relation of the slope to choice behaviour, and its relative dependence on intensity sensitivity and a preference motivation characteristic of the individual and test situation, remain to be elucidated. This procedure should have wide application in consumer preference measurement.

Adult↗