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Biomedical subjects

H Cottier

Publications and source records attributed to H Cottier.

At least 109 records · Page 6Linked to original sources
PubMed1977

Lymphopenia and lymph node histology following repetitive extracorporeal irradiation of blood in normal and thymectomized calves.

Repetitive extracorporeal irradiation of the circulating blood (RECIB) in normal or thymectomized calves and RECIB plus Imuran were used for comparative studies on the depletion of blood and lymph node lymphocytes. Elimination of the easily mobilizable pool of lymphocytes was almost complete within approximately 6 days after commencing RECIB and was reflected by a reduction of approximately 50% in the numbers of paracortical lymphocytes. Blood lymphocyte counts were reduced to approximately 1/3 to 1/4 of the pre-irradiation values. Thymectomized calves had lower pre-irradiation blood lymphocyte counts than non-operated controls, however, the reduction in the number of blood lymphocytes was proportionally similar. Continuation of RECIB beyond one week did not result in a further depletion of blood lymphocytes. The lymphocyte counts in the follicular cortex and in the medulla of lymph nodes were not significantly changed by the various procedures. RECIB of 8-16 days duration did not alter the number of germinal centers in non-thymectomized calves, however, in thymectomized animals treated with Recib, the number of germinal centers was reduced.

Animals↗
PubMed1977

Significance of Hageman factor (coagulation factor XII) for neutrophil locomotion and chemotaxis.

Neutrophils separated from Hageman factor-deficient blood exhibit normal random and directional locomotion. No defect in cytotaxin formation could be demonstrated in Hageman factor-deficient plasma, nor did kallikrein inhibitor interfere with the chemotactic activity of normal immune complex-activated human plasma. The results suggest that the chemotactic activity which is detectable in unfractionated human plasma is not derived from Hageman factor-dependent pathways.

Antigen-Antibody Complex↗
PubMed1977

Fate of thymocytes: studies with 125I-iododeoxyuridine and 3H-thymidine in mice.

Cortical thymocytes of young adult mice were labeled in situ with radioactive DNA precursors. As a result of cell emigration and cell death, total thymic radioactivity decreased within 8 days to 10% or less of that present on day 1. Accumulation of thymic migrants in peripheral lymphoid organs was estimated by computing the net thymus-derived radioactivity in these tissues. Thymic cell death was assessed by comparing values obtained with 125I-UdR to those acquired with 3H-TdR; The results indicate that cortical thymocytes migrate to the spleen, mesenteric lymph node, femurs and intestine; nevertheless, only a small fraction of the activity originally present in the thymus was recovered in these organs; the vast majority of newly formed cortical thymocytes apparently die after a relatively short life span. Exclusive of the fraction which dies in situ, evidence for thymocyte death is seen in bone marrow; however, most migrants appear to terminate in the intestine.

Animals↗
PubMed1977

[Functional lymph node diagnosis].

This short review focuses on recent developments in the field of functional morphology of peripheral lymphoid tissues, in particular of lymph nodes. Emphasis is given to cellular and histological characteristics of lymph nodes in the course of cell-mediated and humoral immune responses. Against the background of regional and age-related changes, selected examples of a functional interpretation of structural changes are presented.

Humans↗
PubMed1976

[Cell division, cytolysis and regeneration after cyclophosphamide].

Cytokinetic effects of 5 or 20 mg cyclophosphamide/kg body weight on thoracic duct lymph and blood cells of calves were analyzed. The larger dose caused a temporary cessation of lymphoid cell division, reduced the output of nondividing small lymphoid cells and impaired proliferation of neutrophil precursors. Feedback mechanisms acting on GO/G1 cells controlled the proliferation of lymphoid cells.

Animals↗
PubMed1976

[Epithelial barriers of the intestine. Significance and function in defense against infection].

The epithelial surface of the intestinal tract provides for an important barrier between the organism and its environment. However, it permits the passage into the tissues of limited amounts of macromolecules and/or particles, especially bacteria. These functions are age- and species-dependent, and they are closely related to nonspecific and specific immune reactions. Continuous and intimate contact between antigenic material from the gut lumen and immunocompetent cells takes place in gut-associated lymphoid tissues.

Bacterial Infections↗
PubMed1976

Bursa of Fabricus: uptake of radioactive particles and radiotoxic "sealing" of bursal follicles.

Making use of the fact that the avian bursa is uniquely equiped for uptake, degradation and storage of particulate matter from the cloacal lumen, we administered 239Pu(IV) perorally or via the cloaca to cause radiotoxic damage to the bursal tissue. This resulted in a involution of the follicles, reduction of the lymphocyte mass, predominance of smaller lymphoid cells in the medulla as compared to controls, disappearance of tuft epithelia, formation of a sub-epithelial fibrous layer in many follicles and impairment or an almost complete loss of the capacity of the bursa to take up particulate matter. Concomitant with these changes was a reduction in the concentration of serum IgG. These findings are discussed in relation to the immunologic contact role of the bursa.

Animals↗
PubMed1976

Problems relating to immunoselection of leukemias.

Problems relating to immunoselection of neoplastic, in particular leukemic, cell lines are reviewed. Since there is ample evidence that specific immune reactions of the host against malignant neoplastic cells do occur, it becomes important to consider the effectiveness and the relevance of immunity in suppression or elimination of neoplastic growth. Emphasis is placed on experimental results obtained in syngeneic tumor-host combinations, because they more closely resemble the situation of spontaneous tumorigenesis or leukemogenesis than xenogeneic or allogeneic model systems. Studies of types of neoplasia observed in cases of human immunodeficiency syndromes offer an important insight into problems involved in immunoselection of leukemic cell lines: the marked predominance of leukemias and lymphoreticular neoplasias in immunodeficient patients invites speculation on both the mechanisms of leukemogenesis and the relative importance of the immune system in eliminating malignant neoplastic cells.

Animals↗
PubMed1976

Studies on the regulation of the neutrophil chemotactic response using a rapid and reliable method for measuring random migration and chemotaxis of neutrophil granulocytes.

An economic and sensitive test system for measuring random and directional migration of human neutrophils is described. The technique, based on a modified Boyden chamber equipped with a two-filter system, permits a substantial reduction of both incubation time and sample volume. The influence of various technical factors such as the neutrophil concentration in the cell suspension, the incubation time of the chambers, the test concentration of activated plasma or serum, the presence of heparin, and the procedure for separating neutrophils from human peripheral blood, was investigated. Standardized procedures for measuring and reporting neutrophil chemotaxis are proposed. The method has been used to study the significance of factors regulating neutrophil migration such as cytotaxin inactivators and neutrophil immobilizing factors (NIF). Activity of cytotaxin inactivators as assessed in undiluted serum or plasma at pH 7.4, 6.0 or 4.0 was very low. In contrast, potent neutrophil immobilizing activity was found in human serum or diluted plasma. These factors which inhibit migration were accordingly termed neutrophil immobilizing factors of plasma (NIF-P) and neutrophil immobilizing factor of serum (NIF-S). These factors are heat-stable, non-dialysable and of high molecular weight.

Antigen-Antibody Complex↗
PubMed1976

Effects of lymph diversion versus corticosteroids on blood and lymphocyte pools.

Thoracic duct-rumen fistulae (TDRF) and low or high doses of Prednisolone were employed to induce depletion of blood and lymph node lymphocytes in calves. Elimination of the easily mobilizable pool of lymphocytes was almost complete within 6 days after commencing TDRF. Blood lymphocyte counts were reduced to approximately 1/3 of pre-TDRF levels. Prednisolone in low doses did not decrease the number of blood lymphocytes. High doses of Prednisolone induced a moderate, progressive blood lymphocytopenia. Both TDRF and low and high dose Prednisolone schedules induced a significant reduction of lymphocytes in lymph nodes. The loss of small lymphocytes from lymph nodes was almost entirely restricted to the diffuse cortical (paracortical) zone. The lymphocyte counts in the follicular cortex and in the medulla were not significantly affected. Almost complete disappearance of germinal centers was observed in lymph nodes of calves subjected to TDRF or high doses of Prednisolone.

Animals↗
PubMed1976

Fate of intraintestinal thymocytes labeled with 125iododeoxyuridine or tritiated thymidine.

A suspension of thymocytes labeled with 125UIdR or 3HTdR was injected into the jejunum of mice. The bulk of the radioactivity disappeared within few hours from the intestine and was recovered principally in the urine. This indicated a very rapid breakdown of labeled thymic cells, reabsorption and subsequent elimination of the tracer in the kidney. In mice injected with cells labeled with 3HTdR, the initial rapid loss of radioactivity was of shorter duration, and slower during the second phase, presumably due to more extensive reutilization and/or prolonged persistence of acid-soluble radioactivity. Pretreatment of the recipients with antibiotics did not significantly reduce the rate of radioactivity loss.

Animals↗
PubMed1976

The fate of thymic radioactivity after local labeling with 125iododeoxyuridine.

The thymic cortex was locally labeled with 125Iododeoxyuridine (125IUdR) in young adult mice in an attempt to provide a simple quantitative assessment of the fate of cortical thymocytes. Similarly operated and nonoperated mice given 125IUdR intravenously were used for comparison. Analogous experiments were performed in adrenalectomized animals. More than 90% of thymic activity present 1 day after labeling had been lost by day 8. That proportion of radioactivity contributed to a given organ by accumulation of labeled thymic migrants was estimated by comparison of values obtained after local labeling with those acquired after systemic labeling. Thymic cell accumulation was apparent in the intestine, spleen, mesenteric lymph node, and femurs of locally labeled mice; however, only a few per cent of the total activity lost from the thymus was accounted for in these lymphoid organs. The pattern of fecal and urinary elimination of 125I did not markedly differ in the various experimental groups, the bulk of the activity being recovered in the urine. The intestine could not be ruled out as a major site of thymocyte loss. Since significant radiation or pharmacologic toxicity was unlikely with the doses of 125IUdR used, the data indicated that the vast majority of newly formed thymocytes dies after a short life and only a small fraction of thymic migrants is longer lived.

Animals↗
PubMed1976

[The blood-xylose test in childhood: correlation between 1 hour blood-xylose levels and numbers of intraepithelial lymphocytes in intestinal mucosa in celiac disease].

In 59 children who underwent diagnostic small-intestinal biopsies the correlation between the intraepithelial lymphocyte infilration of the distal duodenal mucosa and the blood-xylose concentration 1 h after ingestion of 5 g D-xylose was investigated. 16 patients with active coeliac disease had blood-xylose values below 20 mg%, and the correlation between blood-xylose levels and the numbers of intraepithelial lymphocytes in this same group of patients was found to be highly significant. Provided that the methodology is meticulously followed, it is our experience that the one-hour blood-xylose test, in addition to the clinical investigation, facilitates the decision whether or not to perform a small-intestinal biopsy in the diagnosis and follow-up of coeliac disease in childhood. The test however cannot replace the intestinal biopsy which remains the only acceptable criterion for the diagnosis of this disease.

Adolescent↗
PubMed1976

Effects of single cyclophosphamide doses on the kinetics of thoracic duct lymph and blood leukocytes in calves.

After 5 or 20 mg cyclophosphamide per kg body weight, given once i.v., the output in thoracic duct lymph of small and large lymphoid cells, cells incorporating [3H]lymidine in vitro, mitotic cells, pyknotic cells, and/or the number of lymphocytes and neutrophils in peripheral blood were measured in six calves. The median grain count of labeled cells and the DNA content of pyknotic nucleic were determined. After both doses there was an exponential decrease and subsequent recovery of the median grain count. The larger dose caused a temporary cessation of lymphoid cell division, reduced the output of nondividing small lymphoid cells, and probably imparied proliferation of neutrophil precursors. The results suggest that increased cell production during recovery was due to changes in the growth fraction and that feedback mechanisms acting on G0-G1 cells controled the proliferation of lymphoid cells.

Animals↗
PubMed1975

[Testing of granulocyte function].

Recent work on the in-vitro analysis of granulocyte functions is reviewed. Various forms of granulocyte functions defect have been observed in association with increased susceptibility to infectious diseases. Intrinsic cellular defects can be distinguished from secondary impairment of granulocyte functions due to other diseases, iatrogenic causes or humoral defects. In such cases the in-vitro methods for evaluation of granulocyte functions have become an indispensable diagnostic aid.

Blood Bactericidal Activity↗