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Biomedical subjects

D Lewis

Publications and source records attributed to D Lewis.

At least 343 records · Page 19Linked to original sources
PubMed1979

Liver damage associated with perhexiline maleate.

Two patients who developed biochemical and histological evidence of hepatitis while taking the anti-anginal drug perhexiline maleate are described. The pathological changes were those of mild to moderate fatty change together with a hepatitis which resembled alcoholic hepatitis, including in one patient the presence of material which by light microscopy was indistinguishable from Mallory's alcoholic hyalin. However, the predominantly periportal location of this material contrasted with the centrilobular distribution of Mallory's hyaline. One patient showed, in addition, severe atypia of the hepatocytes which was still present in less pronounced form 10 weeks after stopping perhexiline. The other patient had advanced hepatic fibrosis.

Aged↗
PubMed1979

Babesia divergens: the immunisation of splenectomised calves during irradiated piroplasms.

Groups of three splenectomised calves were inoculated with 1 . 2 x 10(10) Babesia divergens-infected erythrocytes irradiated at 24, 28, 32, 36 and 40 kilorads. Control calves were inoculated with 1 . 2 x 10(7) or 1 . 2 x 10(4) non-irradiated parasites. While control animals all experienced severe reactions, animals receiving blood irradiated at 24, 28 and 32 kilorads had mild reactions and were solidly immune to an homologous challenge of 1 . 1 x 10(4) Babesia-infected erythrocytes. Animals receiving parasites irradiated at 36 and 40 kilorads had limited ability to resist the challenge.

Animals↗
PubMed1979

Microstructure of gallstones.

Electron microprobe analysis, x-ray diffraction, and infrared spectroscopy have been used to investigate the nature and arrangement of materials present in gallstones. Calcium phosphate and carbonate deposits present centrally in many stones were mixed with a pigmented phase containing copper and protein. In several stones, the central calcium deposits were surrounded by discrete adjacent layers of calcium bilirubinate and cholesterol. The calcium bilirubinate layer was distinguished from other pigmented layers by its higher protein content and increased iron/copper ratio. This sequence of calcium salt and cholesterol deposition occurred in the outer layers of some stones. The phase relationships shown by the present study are consistent with a biphasic mechanism of stone growth in which calcium salts and lipid were alternately deposited. Calcium salt precipitation has been inferred to initiate the sequence as calcium salts were found at the stone centers. The layer sequence has been discussed in terms of some possible effects of damage to the gallbladder wall caused by the calcium salt deposits.

Adult↗
PubMed1979

Bovine babesiosis: steps towards an irradiated vaccine.

A series of experiments leading towards the field trial of an irradiated blood-derived vaccine against Babesia divergens, common cause of redwater in cattle in Europe, is described. Initially a number of isolates of B. divergens were made from the blood of sick animals in a variety of localities in the british Isles. These isolates were cryopreserved and then characterised by inoculation into groups of spenectomised Friesian calves, whose reactions were statistically analysed. Attempts were made to prepare a vaccine against B. divergens infection using diluted infected blood, but when these failed it was found that irradiation of infected blood within the range of 24 to 32 kilorads and its intravenous inoculation into calves produced the required immune response without pathogenic effects. An irradiated blood-derived vaccine produced by the irradiation of infected blood at 25 or 30 kilorads was used in a field trial in Ireland, and vaccinated calves were protected against a field challenge which caused redwater in 10 control cattle, six of which had severe reactions.

Animals↗
PubMed1978

Detection of goitrin and its heptafluorobutyryl derivative by gas-liquid chromatography with electron capture, electrolytic conductivity and sulfur detectors.

The separation of goitrin by two gas-liquid chromatographic columns, the response of different detectors and the use of the heptafluorobutyric (HFB) anhydride derivative of goitrin to improve sensitivity was investigated. The non-polar 3% OV-1 and the intermediate 4% SE-30/6% SP-2401 on 80-100 mesh Chromosorb W HP gave comparable results and were considered interchangeable. The sensitivities of the electron capture, sulfur 394 nm emission, chlorine and nitrogen Coulson electrolytic conductivity detectors were inadequate for goitrin per se. Chromatography and sensitivity of all detectors to goitrin were greatly improved by using by using the HFB derivative. It was possible to detect 1 to 60 ng of goitrin-HFB in standard solutions. Application of the technique to goitrin-spiked (2 ppm) milk, cleaned up by high-performance liquid chromatography, encountered no problems and was considered satisfactory for all four detectors.

Animals↗
PubMed1978

The morphology of bone mineral crystals.

Electron microscopical observations of the size and shape of bone mineral crystallites have not been in complete agreement with X-ray diffraction findings. The two prevalent viewpoints consider bone mineral crystals to be either rod, or plate like in habit. There appears to be agreement that the smallest dimension of the crystals is about 5 nm, but there is discrepancy in the reported c-axial lengths. The method of dark field imaging is used to obtain a quantitative measurement of the c-axial length distribution in rabbit, ox and human bone: mean c-axial lengths 32.6 nm, 36.2 nm and 32.4 nm, respectively, show no significant difference at the 5% level to the mean c-axial length measured by X-ray line broadening. Both bright and dark field images strongly suggest that bone mineral has a plate like form. Reasons for past discrepancies are discussed.

Animals↗
PubMed1978

B- and T-cell markers in lymphoproliferative disorders with blood and bone marrow involvement.

B- and T-cell surface markers were determined in 26 adult patients with lymphoproliferative malignancies who had bone marrow and blood involvement. The patients in whom more than 60% of the abnormal cells were immunoglobulin-bearing cells were considered to have B-cell lymphoproliferative malignancy. The diagnosis of a T-cell disorder was made in those patients in whom more than 70% of the cells formed E rosettes (T cells). Those patients in whom 30% and more of the abnormal cells did not show B- and T-cell surface markers were regarded as suffering from "null" cell disorder. The B-cell type of lymphoproliferative malignancy was the most commonly encountered (63%) with an equal male to female ratio. In addition, 4 male patients with "hairy-cell" leukaemia were shown to have a B-cell disorder. T-cell disorders were found in 3 male patients; 1 patient had acute lymphoblastic leukaemia and in the other 2 the histopathological diagnosis was well-differentiated lymphoma and Sternberg sarcoma. Four patients with "null" cell lymphoma were found, the histopathological diagnoses in all were poorly-differentiated lymphocytic lymphoma, and 3 of the 4 patients were males. Further haematological investigations of the B-cell and the non-B-cell disorders showed that although the bone marrow was equally extensively infiltrated in both groups, the non-B-cell disroders were more commonly associated with complications of anemia and thrombocytopenia. It is therefore postulated that the abnormal lymphoid cell involved in B-cell disorders is an end-stage cell and not the haemopoietic stem cell.

Adult↗
PubMed1978

Combination chemotherapy including bleomycin in the treatment of advanced Hodgkin's disease.

Fifty-six patients with advanced Hodgkin's disease were treated with a combination of nitrogen mustard, a vinca alkaloid (vincristine or vinblastine), procarbazine, prednisone and bleomycin, given in repeated cycles. Complete remission was achieved in 33 out of 53 evaluable patients (62,5%). The complete remission rate in patients who had received prior radiation therapy alone (65%) was similar to that in previously untreated patients (73%). Patients who had previously received combination chemotherapy, either alone or together with radiation therapy, responded less well to this regimen of therapy, with a complete remission rate of less than 40%. The complete remission rate was not influenced by the histological subtype of the Hodgkin's disease. Twenty-three of the 33 responders (70%) remain in continuous complete remission. The median for this group has not been reached but will be in excess of 24 months. Major bleomycin toxicity was not encountered in this study. Lung function was monitored throughout but no consistent changes were encountered. The degree of haematological toxicity caused by treatment was no greater than would have been expected without bloemycin. Although the results obtained with the 5-drug combination were satisfactory, the follow-up to date does not suggest that the addition of bleomycin to the convention 4-drug regimen has significantly affected the outcome.

Adolescent↗
PubMed1978

The variation in the concentration of plasma amino acids and blood urea in pregnant sows.

Two pregnant sows were fed on a basal diet consisting of equal amounts of ground barley and ground wheat with or without addition of L-lysine hydrochloride. Plasma amino acid and blood urea levels varied according to the time after feeding. Almost all the essential amino acids reached a maximum level after one hour and then declined at four hours after feeding. The results suggested that samples taken at between one and four hours after feeding were responsive to changes in dietary composition and could provide a measure to evaluate the amino acid pattern in relation to feeding. Both plasma amino acid and blood urea data suggested that lysine was the first limiting amino acid in the basal diet.

Amino Acids↗
PubMed1978

Amino acid requirements of the breeding sow: the dietary lysine requirement during pregnancy.

1. Four pregnant sows were used to study lysine requirements by means of the interpretation of values for plasma amino acid and blood urea. Diets containing graded levels of dietary lysine were fed at the rate of 1.82 kg/d. 2. Plasma lysine remained at a low level up to 6.4 g dietary lysine/kg (dry matter basis) and then increased sharply with further increases in lysine intake. 3. Blood urea levels decreased when the dietary lysine content was increased to 6.4 g/kg and then increased at higher dietary lysine concentrations. 4. Both criteria of response indicated that the lysine requirement of the pregnant sow given 1.82 kg diet/d during the later stages of pregnancy does not exceed 10.00 g/d.

Amino Acids↗
PubMed1978

Amino acid requirements of the breeding sow. 2. The dietary lysine requirement of the lactating sow.

1. Two experiments, involving six lactating Landacre x (Landrace x Large White) sows were undertaken to study the lysine requirement of the lactating sow and to identify the second limiting amino acid by means of interpretation of plasma amino acid and blood urea levels. 2. A basal diet composed mainly of equal amounts of ground barley and ground wheat supplemented with mineral and vitamin mixtures was used. This diet was supplemented with synthetic amino acids (lysine threonine, tryptophan, methionine and isoleucine). 3. Plasma amino acid and blood urea values showed a close agreement and indicated that lysine intake above 38.4 g/d was in excess of the requirement level. 4. Plasma amino acid values suggested tryptophan to be the second limiting amino acid whereas blood urea values suggested threonine to be the second limiting amino acids.

Amino Acids↗
PubMed1977

An x-ray study of the paracrystalline nature of bone apatite.

X-ray diffraction from oriented bone sections show that the crystalline apatite content of untreated mature cortical bovine bone has, in fact, a paracrystalline structure (i.e., no long range order). There is anisotropy in both lattice distortions and the sizes of the coherently diffracting domains. The paracrystalline mean distance fluctuations (g) were found to be 1.5 (+/- 0.1)% and 2.9 (+/- 0.2)% for the basal and prism planes respectively, the corresponding paracrystalline sizes being 220 (+/- 20) and 70 (+/- 10) A. The paracrystalline structure became more ordered above 600 degrees C, suggesting the association of hydroxyl and possibly carbonate and other ions with the paracrystalline structure. The paracrystalline model for bone apatite helps explain anomalies between X-ray and electron microscope measurements of crystal size and also more of the biological functions of the crystalline apatite.

Animals↗