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Biomedical subjects

D Hudson

Publications and source records attributed to D Hudson.

At least 55 records · Page 3Linked to original sources
PubMed1985

Measurement of regional gastroduodenal blood flow with iodo [14C]antipyrine autoradiography.

Regional blood flow was measured in the gastroduodenal area by means of iodo[14C]antipyrine autoradiography. The tracer was given intravenously over a short period of time in awake rats followed by cardiac arrest and quick freezing of stomach and duodenum. Dry autoradiography of frozen sections provide a pictorial representation of radioactivity in the different tissue layers. This could be converted to blood flow after incorporation of the time course of blood radioactivity into an operational equation. A high level of resolution was achieved, allowing delineation of blood flow compartments of small dimensions such as single villi and regions within the fundic mucosa. The value of blood flow recorded in resting conditions were in agreement with previous observations with the microspheres technique. Hypotension induced a generalized decrease in blood flow, most marked in the corpus mucosa.

Animals↗
PubMed1984

Monoclonal antibody characterization of Plasmodium falciparum antigens.

We characterized a set of eight monoclonal antibodies produced against Plasmodium falciparum. In an indirect fluorescent antibody assay the antibodies produced small dots of fluorescence in schizonts and individual merozoites. This merozoite-associated dot reactivity occurred with 21 different strains of P. falciparum, but there was no reactivity with other human, nonhuman primate, or rodent Plasmodium species. Three of the monoclonal antibodies precipitated proteins of Mr 145,000, 135,000, and 104,000. Five of the monoclonal antibodies precipitated proteins of Mr 78,000, 63,000, 42,000, and 40,000.

Antibodies, Monoclonal↗
PubMed1983

A monoclonal antibody to rhesus erythrocyte band 3 inhibits invasion by malaria (Plasmodium knowlesi) merozoites.

Receptors on erythrocytes and malaria parasites mediate specific attachment and junction formation between these cells that lead to invasion of the erythrocytes. We identified monoclonal antibody A9 and its subclone A9D3 that bound to rhesus erythrocytes and blocked invasion of the erythrocytes by Plasmodium knowlesi merozoites. The monoclonal antibodies did not block attachment, the initial step in invasion, although swelling and crenation of the erythrocyte, which normally occur after attachment, were rarely observed in the presence of antibody. The monoclonal antibody immunoprecipitated rhesus erythrocyte band 3. It bound to erythrocytes of another Old World monkey, the kra monkey, but not to erythrocytes of New World monkeys, chimpanzees, or man. Since the antibody did not bind to human erythrocytes, we could test for nonspecific toxicity to the parasite by studying the effect of the ascites and purified antibody on invasion of human erythrocytes. The antibody caused a minimal reduction in invasion of human erythrocytes, a reduction no greater than that seen with an unrelated monoclonal antibody. Further evidence that the inhibition was specific came from study of Fab fragments of A9D3. Column-purified Fab fragments reduced invasion of rhesus erythrocytes without affecting invasion of human erythrocytes. Fab fragments preabsorbed with rhesus erythrocytes did not inhibit invasion. From the above data, we conclude that band 3 is involved in a stage in the invasion process after initial recognition.

Absorption↗
PubMed1980

Methionine enkephalin and isosteric analogues. Part II.: Receptor conformation of methionine enkephalin.

Biological activities are reported for two different types of analogues of methionine enkephalin. Cyclic analogues, bridged between the amino- and carboxy- terminals of the parent peptide, are inactive. In contrast, significant levels of activity are displayed by linear isosterically modified analogues in which the Tyr1-Gly2 peptide bond is replaced by either -CH2NH- or -CH2CH2-. Similar replacements of the Gly2-Gly3 peptide bond yield compounds with much reduced potency. These modifications serve as useful probes of the receptor conformation. Based on these findings, a model is proposed for interaction between enkephalin and its receptor.

Animals↗
PubMed1979

Methionine enkephalin and isosteric analogues. I. Synthesis on a phenolic resin support.

An efficient synthesis of methionine enkephalin using a phenolic resin support is described. Analogues modified at their C-termini, such as peptide acids, amides, methyl esters and compounds formed by their reduction, were prepared conveniently from common peptide phenyl ester resins. The resin was used in the synthesis of complex isosterically modified analogues designed to investigate the role of peptide backbone plays in receptor interaction. Free hexapeptide phenyl ester resins underwent intramolecular aminolysis liberating the corresponding cyclic peptides.

Amino Acid Sequence↗
PubMed1978

Influence of ageing on IgE-mediated reactions in allergic patients.

The influence of age and sex has been evaluated in 326 allergic patients on the following parameters: total serum IgE concentration, serum concentration of specific IgE antibodies against seventeen common allergens, mean number of positive allergens, absolute numbers of circulating eosinophils, corticosteroid dependence and response to sodium cromoglycate (DSCG). The results indicate that age and sex significantly influence the IgE antibody production in these patients. The data strongly suggests the appearance during ageing of a progressive natural desensitization. This contrasts with the increased frequency of corticosteroid-dependent cases during ageing. There is an inverse relation between age and response to DSCG therapy.

Adolescent↗
PubMed1978

Electron immunohistochemical evidence for the human intestinal I cell as the source of CCK.

Evidence was obtained by the use of alternate semithin-thin serial secretions for light and electron microsocpy that the I cell is the source of CCK PZ. The antibodies used were raised to a synthetic fragment of the mid part (9-20) of the (1-33) CCK-PZ molecule, and were thus free from any contamination with cross-reacting subpopulations of antibodies that might bind to gastrin.

Cholecystokinin↗
PubMed1977

Specific immunostaining of CCK cells by use of synthetic fragment antisera.

Antibodies to the central fragments 9-20 dodecapeptide sequence of CCK were used for specific immunostaining of the CCK cells of the mammalian gut. The use of high specific antibodies to synthetic fragment, essential when there is a possibility of immunochemical cross reactions between antisera and hormones of similar molecular structure provides the key to increased understanding of the nature and relationships of peptide hormones.

Antibody Specificity↗
PubMed1977

Influence of levamisole on the immune response of old people.

Fifteen healthy people, over 70 years old, have been treated during 1 month with Levamisole at the dose of 150 mg a day, twice a week. They have been compared to 15 controls matched for age and sex. At the start of the study, each subject was injected with 0.2 ml of a diphtheria-tetanus vaccine. Levamisole had no effect on the following immune parameters known to be altered in old age: serum IgE concentration, specific IgE and IgG antibody response to diphtheria toxin, lymphocyte response to phytohemagglutinin (PHA). There was a slight and transitory effect of Levamisole on the isohemagglutinin titer. In vitro, Levamisole was weakly mitogenic for the peripheral blood lymphocytes from old and young control subjects but there was no influence on the response to PHA.

Aged↗