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Biomedical subjects

D C Kilpatrick

Publications and source records attributed to D C Kilpatrick.

54 records · Page 3Linked to original sources
PubMed1984

A comparison of tomato (Lycopersicon esculentum) lectin with its deglycosylated derivative.

A deglycosylated derivative of tomato (Lycopersicon esculentum) lectin was prepared with the use of trifluoromethanesulphonic acid. Its properties were generally similar to those of the native lectin, but differences were evident in terms of relative agglutinating activity towards sheep, (untreated) human and trypsin-treated human erythrocytes. The two forms of tomato lectin were used in conjunction with a battery of specific antisera to investigate structural relatedness among solanaceous lectins. Immunological cross-reactivity between tomato, potato and Datura lectins depends on the integrity of the glycosylated region of those lectins; that between Datura lectin and other seed lectins, however, has a separate structural basis.

Cross Reactions↗
PubMed1984

Histocompatibility antigen frequencies in patients with chronic lymphocytic leukaemia: possible identification of a subgroup with relatively benign disease.

A series of 57 patients with chronic lymphocytic leukaemia was typed for HLA-A, B and DR antigens and compared with a control population of equal size. There was an increased frequency of HLA-A1 and B8 in the patient group, although it was not statistically significant after allowance for the number of specificities tested. A subgroup of patients lacking both A1 and B8 differed from the others in sex ratio, degree of lymphocytosis and incidence of hypogammaglobulinaemia at presentation. This subgroup also had less need for treatment within 6 months of presentation. While these findings must be considered preliminary, it is possible that tissue typing may help to identify patients with a relatively benign form of the disease.

Aged↗
PubMed1983

Enzymatic modification of the lymphocyte surface. Application to tissue typing and rosetting with sheep erythrocytes.

Lymphocytes were treated with hydrolytic enzymes primarily to assess whether such modified cells would give improved cytotoxicity reactions during tissue typing. Papain-treated and alpha-chymotrypsin-treated lymphocytes were approximately twice as sensitive as untreated cells in the microcytotoxicity test used, and this finding might be usefully exploited by immunological laboratories for purposes of cross-matching, HLA antibody screening and HLA-DR typing. Trypsin treatment promoted massive cell clumping, while neuraminidase treatment was responsible for indiscriminate cell death after exposure to rabbit serum. The capacity of lymphocytes to form rosettes with sheep erythrocytes was abolished after treatment with trypsin or alpha-chymotrypsin, but enhanced by papain or neuraminidase.

Animals↗
PubMed1979

Tissue and subcellular distribution of the lectin from Datura stramonium (thorn apple).

Plants of Datura stramonium (thorn-apple) were dissected into their component tissues and examined for the presence of the Datura lectin. This lectin was easily detected in seeds and in various parts of the flowers of adult plants. Traces were also found in green (emerged) cotyledons and roots of seedlings. The specific lectin activity in seeds contained within the fruits increased as the seeds matured. Mature seeds were homogenized in sucrose and separated by differential centrifugation into four fractions, three of which were clearly of distinct composition. Most of the lectin activity sedimented with the low-speed (cell-wall/protein-body) pellet, but a similar specific activity was recovered from the other fractions. However, if EDTA was included in the homogenization medium, three or four times more lectin activity was recovered in the soluble fraction. Immunofluorescent staining of formaldehyde-fixed sections showed that the lectin was localized in the cytoplasm, with little associated with cell walls. The possible relevance of these results to the function of the lectin in plant cells is discussed.

Datura stramonium↗
PubMed1978

Purification of the lectin from Datura stramonium.

The lectin from Datura stramonium can be inhibited by oligomers of N-acetylglucosamine. This property was exploited to purify the lectin by affinity chromatography on Sepharosefetuin. The purified lectin is a glycoprotein in having subunits of 40 000 and 45 000 mol.wt.

Acetylglucosamine↗
PubMed1978

Carbohydrate composition of cells and plasma membranes of Dictyostelium discoideum at selected stages of development.

Cells of Distyostelium discoideum representing four developmental stages were auto-analysed for constituent monosaccharides and their compositions compared. Rhamnose, ribose, fucose, glucose, mannose, galactose, glucosamine, galactosamine and an unidentified sugar were recovered after hydrolysis in 2 M HCl for 2 h at 100 degrees C. The relative proportions of the individual sugars were found to vary as a function of development. The largest variations were in the proportions contributed by galactose (from 2% of vegetative cell carbohydrate to 12% of the carbohydrate of fruiting bodies) and galactosamine (present in measurable quantity only in fruiting bodies). Plasma membrane "ghosts" were found to have the same monosaccharide constituents as whole cells, but in different proportions. Mannose contributed over 24% of the total carbohydrate recovered from aggregating cell "ghosts", but only 13% of carbohydrate recovered from "ghosts" prepared from vegetative cells. Galactose was the most abundant sugar recovered from vegetative "ghosts", and was second only to mannose in aggregating "ghosts".

Amino Sugars↗
PubMed1977

Glycosidases from the culture medium of Physarum polycephalum.

Eight exo-glycosidase activities were detected in the axenic culture medium of the myxomycete, Physarum polycephalum. The secretion of each enzyme examined followed the growth curve and continued during the stationary phase after the cessation of growth. Two or more forms of each enzyme were detected after electrophoretic separation. The beta-N-acetyl-D-hexosaminidase activity was readily separated into its two electrophoretic forms, X and Y, which were purified 145- and 306-fold respectively. These beta-N-acetyl-D-hexosaminidases had several similar characteristics. Evidence is presented that the major electrophoretic form of alpha-D-galactosidase is heterogeneous. The possible functions of extracellular glycosidases in teir occurrence and properties.

Culture Media↗
PubMed1976

Properties and developmental regulation of an alpha-d-galactosidase from Dictyostelium discoideum.

An alpha-D-galactosidase was detected in cells of the cellular slime mould, Dictyostelium discoideum, at all stages of development. Its specific activity was highest during early development (interphase), and this accumulation of enzyme appears to require protein synthesis de novo. Its subcellular distribution differs from that of other D. discoideum glycosidases, since most activity was recovered in the soluble fraction. No evidence was obtained for more than one isoenzymic form after subjection of extracts to electrophoresis and various chromatographic procedures. It is excreted from the cell during development, but no evidence was found for an extracellular function for the enzyme.

Cycloheximide↗
PubMedDate not supplied

HLA antigen frequencies in children born to HIV-infected mothers.

Tissue-typing for HLA-A, B, and DR antigens was carried out on 53 babies, 47 of them unrelated, born to mothers known to be HIV-infected from intravenous drug usage or sexual contact with drug users. These babies were followed up to assess whether HLA phenotype was associated with vertical transmission of HIV infection or disease progression. Of the 47 unrelated babies, eight became infected with HIV. The frequency of HLA-DR3 was three times higher in the HIV-positive infants compared to the HIV-negative infants (43 per cent vs 15 per cent) in our study population. Conversely, HLA-A3 was three times less common in the HIV-positive infants (12.5 per cent vs 42 per cent). A comparison of HLA antigens between our study group babies and babies born to healthy mothers unselected for HIV status revealed higher proportions of HLA-B18, B7, and DR2 in the study group. Moreover, the combination, A3, B7, DR2 was four times commoner in our study population relative to controls (RR = 3.9; p less than 0.003), but was found only in babies who were not HIV infected. The combination A1, B8, DR3, in contrast, was found less often than expected in our study group (RR = 0.39) and was disproportionately represented amongst the infected babies. We have observed an unexpectedly low (6 per cent) mother-to-infant transmission rate of HIV among prospectively studied intravenous drug users. We speculate that the unusually high ratio of the common antigen combinations (often halotypes), A3, B7, DR2 to A1, B8, DR3 in this population may be contributory.

HIV Infections↗
PubMedDate not supplied

Immune profile of women experiencing recurrent spontaneous abortions of unknown aetiology.

Immunological and immunogenetic investigations are described in a group of 28 women with a history of unexplained recurrent (greater than or equal to 3 consecutive) spontaneous abortions (RSA). Compared with female blood donor controls, recurrent aborters had significantly elevated mean serum complement C4 (p less than 0.05), but not C3, levels. Immunoglobulin levels and T4:T8 ratios showed a similar distribution to the controls. Mixed lymphocyte reactivities to partners' lymphocytes were low in some of the patients, but hyporesponsiveness correlated well with husband-wife HLA-DR compatibility. No individual HLA specificity was significantly increased in the RSA patients, but the combination A3, B7, DR2 was common (p less than 0.02), and general HLA antigen sharing with partners was significantly increased (p less than 0.004) relative to obstetrically normal couples. RSA women who shared two or more HLA antigens with spouses had higher mean serum immunoglobulin concentrations, which for IgM reached statistical significance (p less than 0.05).

Abortion, Habitual↗