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Biomedical subjects

H Cottier

Publications and source records attributed to H Cottier.

At least 73 records · Page 4Linked to original sources
PubMed1983

Uptake by enterocytes and subsequent translocation to internal organs, eg, the thymus, of Percoll microspheres administered per os to suckling mice.

The translocation of Percoll microspheres (mean diameter 20-30 nm) from the intestinal lumen through the epithelial layer to internal organs was examined in suckling mice using transmission electron microscopy. Repeated administration of this material by gavaging for 7 consecutive days resulted in a heavy particle load of vacuolated enterocytes. A limited amount of Percoll was transported to the subepithelial tissue of both the villous mucosa and Peyer's patches where microspheres were found endocytosed, predominantly by macrophages. Even smaller numbers of particles reached mesenteric lymph nodes and, occasionally, milky spots of the omentum. Minor Percoll aggregates were easily found in Kupffer cells of the liver, indicating hematogenous translocation. Small numbers of particles were regularly detected in perivascular macrophages of the thymic cortex, which are in close contact with surrounding lymphocytes. We conclude that the thymic cortex is not totally inaccessible to particulate matter of the intestinal content.

Animals↗
PubMed1983

Distinct kinetic responses in vivo of cortical thymocytes of ageing mice to primary as compared to secondary peripheral antigenic stimulation.

We have studied cellular kinetic changes in the thymic cortex of ageing mice as a function of time after primary and secondary stimulation with aluminum phosphate adsorbed tetanus toxoid via the hind leg footpads. Absolute numbers of DNA synthesizing cortical thymocytes per cross-section of the thymus were computed from combined data obtained by planimetry, counts of cell density (cellularity) and assessment of the labelling index, 1 h after injection of (methyl-3H)-thymidine. The proliferative activity of these cells in the outer fourth of the thymic cortex reached a peak exceeding significantly control values by 45% 14 days after primary, but not secondary, peripheral antigenic stimulation. We conclude that the cortical thymocyte population responded in a distinct manner to the first immunization as opposed to the booster injection of the same antigen.

Aging↗
PubMed1982

Macrophage functions in antimicrobial defense.

In the present short review article, we discuss some recent findings regarding the role of macrophages in antimicrobial defense. Problems that are briefly considered include the production of monocytes and its modification in infectious diseases; the role of circulating monocytes and "fixed" macrophages in the blood stream; emigration of monocytes from the vascular bed and their accumulation at sites of microbial attack; role of macrophages in immune responses; stimulation and activation of these cells including secretory functions; attachment to their surface and phagocytosis of microorganisms; microbicidal activities of macrophages; their role in granuloma formation; inherited and acquired deficiencies of macrophage functions. Emphasis is placed on currently unresolved problems.

Animals↗
PubMed1982

Leucocyte activation and the assessment of leucocyte locomotion.

Leucocyte activation by different agents does not result in a uniform pattern of parallel responses. Some activities have synergistic and others antagonistic effects on directional locomotion in vitro. No reliable correlation between chemotaxis on the one hand and other leucocyte activities such as crawling movements, adhesion to solid substrata and chemokinesis has been firmly established. Therefore, the assessment of chemotaxis by measuring orientation is presumably the only reliable quantitative measure for chemotaxis.

Cell Adhesion↗
PubMed1982

Congenital "histiocytoid" cardiomyopathy: evidence suggesting a developmental disorder of the Purkinje cell system of the heart.

The so-called "histiocytoid cardiomyopathy" is an unusual cardiac disorder of infancy and childhood, characterized by the presence of numerous foamy, lipid-containing cells between the endocardium and the striated myocardial cells of the left ventricle and the interventricular septum. The disease usually affects females, the clinical picture being dominated by severe disturbances of conduction. The original designations of the disorder stem from the morphological resemblance of the foamy cells to lipid-laden histiocytes. However, subsequent investigations have shown these cells to contain myofibrils interposed with Z lines. It has, therefore, been suspected that the leading cell population might be related to the myocardium. Using a histochemical method for the demonstration of cholinesterase activity in the foamy cells, we present evidence that "histiocytoid" cardiomyopathy may in fact correspond to a maldevelopment of the Purkinje cell system of the heart.

Cardiomyopathies↗
PubMed1982

The role of 2-mercaptoethanol in the stimulation of spleen cell cultures: increased uptake of cystine into the TCA-soluble pool.

A sensitive system for the study of the mechanism of action 2-mercaptoethanol in stimulating of mouse spleen cell cultures is described. In this system the triggering of stimulation of cells by a mitogen or antigen was dependent on the presence of 2-mercaptoethanol (2-ME) in the medium. To obtain a similar stimulatory effect, 2-ME could be replaced by L-cystine or L-cysteine in the presence or absence of a mitogen. In the presence of a mitogen and below the saturation level, cystine was more effective than cysteine. By increasing in this system, the cystine concentration, to the double of that of the basal medium, a strong stimulation of cells was produced. Conversely, in the absence of mitogen, cysteine was significantly more effective than cystine. Addition of 2-ME led to an increased entry of [14C]L-cystine into the TCA-soluble pool of cells while the thiol had no influence on the uptake of a mixture of different amino acids. We conclude that in this system the role of 2-ME is to enable the utilization of otherwise ineffectively low concentrations of cystine by enhancing the entry of this amino acid into the amino acid pool of the cells.

Animals↗
PubMed1982

A new procedure to analyse the role of adhesion to solid substrata and of motility in chemokinesis of neutrophil granulocytes.

The role of crawling movements and of adhesion to the substratum in chemokinetic responses of neutrophil granulocytes is determined by a new procedure. The results show that this type of analysis is required to understand complex chemokinetic responses. Human serum albumin (HSA) was found to exert its chemokinetic effect exclusively by modulating adhesion to the substratum. In contrast, the positive chemokinetic effect of f-Met-Leu-Phe (10(-8)M) is essentially due to its capacity to induce crawling-like movements, but depending on the test conditions it may or may not affect adhesion as well. The findings indicate that different mechanisms controlling chemokinesis may produce antagonistic effects on the rate of dislocation.

Cell Adhesion↗
PubMed1982

Involution patterns of the human thymus. I Size of the cortical area as a function of age.

Thymic tissue obtained at autopsy from 123 victims of sudden death, ranging from neonates to individuals older than 80 years and predominantly male, was studied with histometric techniques, i.e. a combination of test point analysis and planimetry on unit optical fields. The pattern of 'natural' age-dependent involution of the thymic cortex was examined using computerized mathematical models. The range of variations of results was greatest in children and young adults, followed by the very old, then the middle age group. In a first approximation, regression for thymic cortical volume in individuals older than 15 years corresponded better to a negative exponential than to a negative linear function of age. Best fits for the data suggest at least a two-component negative exponential function of age, with a steeper slope of the regression for individuals beyond the age of 30 years. Extrapolation on a log-normal plot of regression lines for thymic cortical involution points to near-zero values at an age range below the estimated maximum human life span, corresponding to the steepest slope of survival curves in Western Europe.

Adolescent↗
PubMed1982

[Arterial lesions in childhood: possible precursors of atherosclerosis].

The mini-review on pathogenesis and possible etiologies of human atherosclerosis puts its emphasis on the arterial lesions preceeding clinically manifest atheroma-formation. These lesions which arise from childhood onwards may be caused by a variety of factors such as mechanical stress, immune complexes, infection, toxic products and hyperlipemia.

Age Factors↗
PubMed1981

Crawling-like movements and polarisation in non-adherent leucocytes.

Leucocytes, in an appropriate medium, are polarized and show movements both when floating in suspension and when settled on, but not attached to, a substratum. These movements are similar to those performed during locomotion but significant active locomotion on a plain surface is invariably accompanied by adhesion to the substratum as detected by reflection contrast microscopy. The results suggest that the polarisation and crawling-type movements represent a fixed action pattern which is performed independently of adhesion to the substratum.

Cell Adhesion↗
PubMed1981

Nonspecific esterase in human lymphocytes.

A substantial proportion of human peripheral lymphocytes exhibits esterase activity as demonstrated by cytochemical techniques using hexazotized pararosanilin as coupling agent and different alpha-naphthyl compounds, in particular alpha-naphthyl-acetate, as substrates. Esterase-positive lymphocytes showed one or several dots of the reaction product. Plasma cells and macrophages also exhibited marked esterase activity but with diffuse distribution of the reaction product throughout the cytoplasm. The substrate specificity, the time course and the pH optimum of the cytochemical reaction were determined. The results indicate that these lymphocyte esterases are identical with acid lipases. The number of esterase-positive cells reaches a plateau well below 100% (85% for blood lymphocytes) even with optimal staining procedures. The relation between esterase activity and other so-called lymphocyte markers such as sIg and the capacity to form spontaneous rosettes with sheep red blood cells was investigated in peripheral human blood lymphocytes. A fair correlation between rosette formation and esterase activity was found and most of the esterase-positive cells were sIg-negative. However, the fit was never complete. The results suggest that esterase activity is largely characteristic for small peripheral T cells. Almost all blast cells formed following stimulation with Con A or PHA were esterase-positive. Histochemical studies showed that the large majority of the thymocytes in the cortex lacked esterase activity. In lymph nodes, a low proportion of esterase-positive cells was found in the germinal centers, whereas most lymphocytes in the paracortical are were esterase-positive.

Adolescent↗
PubMed1981

Amyloid-containing renal interstitial cell nodules (RICNs) associated with chronic arterial hypertension in older age groups.

A highly significant correlation is demonstrated between the presence in older persons of medullary renal interstitial cell nodules (RICNs) containing amyloid and increased heart weight indicative of chronic arterial hypertension. By contrast, the population with amyloid-free RICNs 1) showed heart weights comparable to those of controls and 2) had a mean age about 11 years less (56.7 +/- 9.6 vs 68 +/- 12 years) than the group with amyloid-containing RICNs. In a series of 55 autopsy cases presenting with RICNs, no individual was younger than 30 years. In two cases, in which fresh material was available, histochemical reactions suggested that the RICNs contained APUD amyloid. It is speculated that fully functional RICNs may evolve on a compensatory base counteracting an increase in mean arterial blood pressure and that the deposition of amyloid within RICNs could be associated with, or be an expression of, a reduced endocrine function of these structures, finally resulting in the development of arterial hypertension.

APUD Cells↗