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Biomedical subjects

J de Groot

Publications and source records attributed to J de Groot.

45 records · Page 3Linked to original sources
PubMed1979

A study of cells present in peripheral lymph of pigs with special reference to a type of cell resembling the Langerhans cell.

Large mononuclear cells with long, actively moving cytoplasmic veils were observed in lymph coming from the skin. The enzyme histochemistry and ultrastructure of these cells suggested that they are related to epidermal Langerhans cells and interdigitating cells in the lymph node. It has been reported that Langerhans cells and interdigitating cells play a role in contact hypersensitivity by taking up antigen and presenting it to thymus-dependent lymphocytes, and it is likely that the veiled cells in the lymph are also involved. After skin-painting with 1-fluoro-2,4-dinitrobenzene (DNFB), the veiled cells in lymph coming from the site of painting became more active and were observed contacting other cells present in the lymph; many large cellular aggregates were found. Since neutrophilic leucocytes and mononuclear phagocytes were the predominating cell types in this lymph, there was no evidence for a massive recruitment of immunocompetent lymphocytes at the site of painting. Neonatally thymectomized pigs do not develop allergic reactivity to DNFB. It is of interest that the number of veiled cells and their ability to form large cellular aggregates was not affected in these animals. Therefore, it is unlikely that the defect in responsiveness can be attributed to a failure in the function of veiled cells.

Acid Phosphatase↗
PubMedDate not supplied

Immunity in barren and enriched housed pigs differing in baseline cortisol concentration.

It was shown in a recent study [De Jong IC, Prelle IT, Van de Burgwal JA, Lambooij E, Korte SM, Blokhuis HJ, Koolhaas JM. Effects of environmental enrichment on behavioral responses to novelty, learning and memory and the circadian rhythm in cortisol in growing pigs. Physiol Behav, in press.] that barren housed pigs (small pens, no substrate) have a blunted circadian rhythm of salivary cortisol as compared to enriched housed pigs (large pens with daily fresh bedding). In the light period, enriched housed pigs showed significantly higher concentrations of cortisol in saliva than barren housed pigs, whereas in the dark period, cortisol concentrations were low in both enriched and barren housed pigs. In the present study, the immunological consequences of the difference in baseline salivary cortisol concentration in the light period were evaluated. It appeared that leukocyte and lymphocyte distributions, and in vitro lymphocyte proliferation following ConcanavalineA (ConA) stimulation in the assay using purified lymphocytes were not affected. However, barren and enriched housed pigs did show a different proliferation response to ConA in the whole blood assay. At day 2 of culture, proliferation was higher in barren housed pigs than in enriched housed pigs, whereas at day 4 of culture, proliferation was higher in enriched housed pigs than in barren housed pigs. Lymphocyte proliferation at day 2 of culture in the whole blood assay correlated negatively with plasma cortisol levels, which might thus explain the higher proliferation in barren housed pigs at day 2 of culture. The in vivo humoral and cellular (delayed type hypersensitivity, DTH) immune response to KLH was not affected by housing conditions. We conclude that, although baseline salivary cortisol concentrations differ between enriched and barren housed pigs, immune function appears to be relatively unaffected.

Animals↗
PubMedDate not supplied

Electromyography of shoulder muscles in relation to force direction.

In a static force task the electromyographic level of 14 shoulder muscles including 3 rotator cuff muscles was related to force direction. Surface and wire electrodes were used. The force direction of maximal electromyography (principal action) was identified for every muscle. The principal action expresses the function of a muscle in a special situation. The deltoid was active in a force direction that could be understood from its anatomy. The trapezius and serratus were mainly involved in stabilizing the scapula in upward and outward force directions. Large multiarticular muscles such as the pectoralis and the latissimus were active in downward and forward forces. The rotator cuff seems to have a specific role in stabilizing the glenohumeral joint. These data can be compared with data of patients with shoulder disorders and with kinematic data of a shoulder model.

Adult↗
PubMedDate not supplied

Analysis of trypsin inhibitors and lectins in white kidney beans (Phaseolus vulgaris, var. Processor) in a combined method.

Buffered saline extraction, affinity chromatography, and Folin-BSA protein assay were used consecutively to provide a combined method for analysis of trypsin inhibitors and lectins in white kidney beans (Phaseolus vulgaris, var. Processor). The method was tested by following the decrease of both antinutritional factors by germination of the beans for 7 days at 20 degrees C. Repeatability coefficients of variation were 2-7.4% for the trypsin inhibitors and 2.2-10% for the lectins. After 7 days of germination, trypsin inhibitors and lectins were reduced by 72 and 92%, respectively.

Chromatography, Affinity↗
PubMedDate not supplied

Simultaneous enumeration of T-cell subsets and macrophages in bronchoalveolar lavage fluids by immunoenzyme double staining. Comparison with conventional immunofluorescence.

Bronchoalveolar lavage is a common research and clinical tool for the retrieval of cells from the lower respiratory tract. In addition to conventional morphologic study of these cells, the subtyping of T lymphocytes is often important for reaching a diagnosis of a disease or assessing its activity; subtyping is usually done by a standard immunofluorescence assay on cell suspensions requiring about 5 X 10(5) cells. Since the number of leukocytes in the lavage fluid from many patients is too small to obtain reliable information by this assay, a double immunoenzyme staining of T-lymphocyte subtypes on Cytospin preparations was utilized. This method, which requires a small number of cells, was compared with the standard immunofluorescence assay for the identification and quantitation of lymphocyte subtypes in the lavage fluids of patients with different disorders. Although the immunoenzyme double staining assay is somewhat more laborious, it provides important advantages: (1) simultaneous observation of two lymphocyte subsets and macrophages on the same slide; (2) a considerably smaller number of cells (2 X 10(4) instead of 5 X 10(5] is necessary; (3) the availability of permanent preparations; (4) the possibility of storing the Cytospin slides before staining; and (5) conventional light microscopy can be used. Since the reliability of both techniques appeared to be the same, the double staining assay for routine usage with bronchoalveolar lavage fluids appears to be preferable.

Bronchoalveolar Lavage Fluid↗
PubMedDate not supplied

MR imaging of the aging brain: patchy white-matter lesions and dementia.

Magnetic resonance (MR) imaging studies of the brain in five elderly patients with non-Alzheimer dementia were compared with those in two groups of nondemented control subjects. Group 1 included five subjects aged 59-66; group 2 included nine subjects aged 74-81. In all of the demented patients and in three of the subjects in the older control group, MR showed diffuse, patchy white-matter lesions. A rating scale was used to grade the severity of the changes. The results suggest a higher incidence of white-matter lesions in elderly patients with non-Alzheimer dementia and in cognitively normal elderly with advancing age.

Age Factors↗