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Biomedical subjects

C L Wilson

Publications and source records attributed to C L Wilson.

At least 73 records · Page 4Linked to original sources
PubMed1994

Cells in the bulge of the mouse telogen follicle give rise to the lower anagen follicle.

The slow-cycling cells in the bulge of the outer root sheath may represent stem cells for the hair follicle. With each new anagen (growing) phase bulge cells would give rise to a population of transient-amplifying cells which differentiate into outer root sheath and matrix keratinocytes. The lowermost part of the telogen (resting) follicle is composed of bulge cells lying in close proximity to the dermal papilla. In the mouse the first hair follicle growth is characterized by rapid follicular neogenesis, but the second and third growth cycles follow the normal follicular growth pattern. We have examined activity of cells in the bulge at the onset of anagen (growing phase) in the third hair cycle in Sencar mice, by treating animals at the end of the second telogen with colchicine to localize mitotic activity in the hair follicle. Mitoses were only seen in bulge cells during early anagen. This confirms that they proliferate transiently, solely at the onset of anagen and strongly supports the suggestion that bulge cells are the origin of the whole lower follicle in anagen.

Animals↗
PubMed1993

An immunohistological study of desmosomal components in pemphigus.

Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are autoimmune diseases in which there is loss of cohesion between keratinocytes (acantholysis) and blistering within the epidermis. PV is characterized by acantholysis predominantly between the epidermal basal cells and suprabasal layers, whereas in PF intraepidermal cleavage is higher in the epidermis. Adhesion between keratinocytes is dependent on the function of transmembrane glycoproteins of the cadherin family present in specialized adhesion junctions, the desmosomes. The pathogenesis of acantholysis in pemphigus is uncertain, but the pemphigus autoantibodies bind to epithelial cadherins. We have used monoclonal antibodies to desmosomal components to investigate their distribution in different forms of pemphigus. Our results show that the localization of desmosomal components is abnormal in intact perilesional epidermis, intact epidermis above the blisters in PV and intact epidermis below the blisters in PF. We suggest that autoantibody binding may have a direct effect on the function of specific epithelial cadherins, but will only cause cell separation where the antigen is the principal adhesion molecule.

Acantholysis↗
PubMed1993

IgG subclasses in pemphigus in Indian and UK populations.

The autoimmune blistering disease pemphigus is more common in the Indian subcontinent than in the UK. This study of 19 patients from Oxford, UK and 39 patients from New Delhi, India demonstrates that the incidence of the disease subtypes is different in the two countries. In the UK the commonest subtypes are pemphigus vulgaris and foliaceus with equal prevalence (both eight of 19), but in India pemphigus vulgaris is the most frequent (31 of 39), while pemphigus foliaceus is uncommon (three of 39) and with equal prevalence to the other subtypes. These populations also differ with a younger age at onset in the Indian patients (36.9 India; 52.7 UK) though the sex distribution is the same. Study of the immunopathology shows that the antibodies produced by patients in the two countries do not differ significantly, and are predominantly of the IgG4 subclass. The antibody produced does not vary with the subtype of pemphigus or the age or sex of the patient. Although there are considerable differences between the two groups of patients this difference is not reflected by the subclass of auto-antibody response.

Adult↗
PubMed1993

Establishing the first family medicine program in Ecuador.

The first family medicine residency program in Ecuador was founded in 1987 by a private evangelical mission hospital under the auspices of the Catholic University of Cuenca. Currently, general medicine is an empiric and poorly respected profession, and medical care is fragmented among multiple specialties and competing systems. This paper reviews the basic principles that guided the development of the program and some of the major challenges and difficulties it has faced. The most important principle of this program is the development of family physician role models who work among other health care professionals and contextualize the basic principles of family medicine to fit Ecuadorian society and its medical needs.

Curriculum↗
PubMed1992

The alternatively spliced V region contributes to the differential incorporation of plasma and cellular fibronectins into fibrin clots.

During blood clot formation in vivo, plasma fibronectin (pFN) is cross-linked to fibrin by coagulation factor XIIIa. Cellular FN (cFN), which localizes to connective tissue, is distinguished from pFN by the inclusion of alternatively spliced segments. To determine if these two FNs are functionally equivalent in blood clotting, the cross-linking of rat pFN and cFN to fibrin was compared in an in vitro clotting assay. Fibrinogen and FN were incubated at physiological ratios in the presence of thrombin and factor XIIIa. Cross-linking of FN to fibrin was monitored by SDS-PAGE and immunoblotting. Over 24 h, cFN was incorporated at a significantly slower rate than pFN and was not completely cross-linked to fibrin at a temperature that favors this interaction (0 degrees C). This difference was observed with purified fibrinogens from human, rat, and bovine and with rat plasma and was maintained even after incubation of pFN with rat fibroblasts for several days. Using the same assay, purified recombinant V(+)-V0 and V(+)-V+ FN dimers resembling pFN and cFN, respectively, showed a similar difference in cross-linking kinetics. These results suggest that the asymmetric distribution of the V region among pFN dimers plays a role in regulating its incorporation into blood clots. In fibrin clots, cFN was converted into a set of cross-linked intermediates distinct from those of pFN. For example, while pFN was initially cross-linked into a pFN-fibrin alpha heterodimer, this product was not a major intermediate in clots formed with cFN. This finding, in conjunction with evidence for the formation of factor XIIIa-catalyzed cFN-cFN cross-links, indicated that cFN molecules interact with each other, and with fibrin, differently from pFN. Together, these results show an important functional distinction between pFN and cFN.

Alternative Splicing↗
PubMed1992

Clinical and microbiologic characteristics of cutaneous infection with Yersinia enterocolitica.

The clinical and microbiologic features of primary cutaneous infections by Yersinia enterocolitica are described in three children. Vesiculobullous lesions developed in two patients, and an intense granulation response followed incision and drainage. In the third child, cellulitis and abscess formation developed at the site of minor skin trauma. Y. enterocolitica isolates from the patients were extensively serologically, biochemically, and molecularly analyzed and compared with virulent Y. enterocolitica strains. The ability of the isolates to adhere to and invade eukaryotic cells was determined using in vitro assays; virulence was assessed by inoculation of suckling mice. The resulting data suggest that primary cutaneous infections by Y. enterocolitica involve strains that are as virulent as pathogenic gastrointestinal isolates.

Animals↗
PubMed1992

Scarring alopecia in discoid lupus erythematosus.

The clinicopathological features of the scarring alopecia of discoid lupus erythematosus (DLE) were studied. Scarring alopecia was present in 34% of 89 patients with DLE and was associated with a prolonged disease course. More than half these patients had scalp involvement at the onset of the disease. There was a significant reduction in size of sebaceous glands in affected scalp. Perifollicular lymphocytic inflammation was maximal around the mid-follicle at the level of the sebaceous gland, which seems to be an important functional level in the follicle. There are changes in the expression of the matrix molecules, the proteoglycans, in the connective tissue sheath and the keratin intermediate filaments in the outer root sheath cells at this level in normal scalp and in diseased scalp. Loss of a population of mid-follicular stem cells may be important in the pathogenesis of scarring alopecia in DLE.

Adolescent↗
PubMed1991

Functional connections in the human temporal lobe. II. Evidence for a loss of functional linkage between contralateral limbic structures.

In a previous investigation of functional limbic pathways in the human mesial temporal lobe, we found evidence for strong connections between ipsilateral mesial temporal structures, but none for contralateral functional connections (Wilson et al. 1990). In the present study, we focused specifically upon the question of functional commissural linkages between these structures by systematic stimulation of a total of 390 electrode placements in 74 epileptic patients with temporal lobe depth electrodes implanted for surgical diagnosis. Eight standard electrode placement regions were targeted: amygdala, entorhinal cortex, anterior, middle and posterior hippocampus, subicular cortex, middle parahippocampal gyrus, and posterior parahippocampal gyrus. Three to six electrodes were implanted bilaterally in each patient, and each electrode was individually stimulated while recording from all the other sites. Out of the 390 electrodes stimulated, 78% were effective in evoking clear responses in adjacent ipsilateral structures, and 75% of 581 ipsilateral recording sites were responsive to stimulation. Only one of the stimulated electrode sites was effective in evoking responses in contralateral recording sites, and only two of 511 contralateral recording sites were responsive to that stimulation. The effective stimulation site was in presubicular cortex, and the responsive contralateral recording sites were in entorhinal and presubicular cortices. Response to this stimulation site was intermittent and variable in latency. The relative ease of obtaining functional verification of significant ipsilateral anatomical pathways in the human limbic system, and the sharply contrasting difficulty of functionally activating commissural pathways to contralateral limbic sites are discussed in the context of decreases in hippocampal contribution to commissural pathways in the primate brain compared to sub-primate mammals, and the significance of this change to normal limbic system function as well as to mechanisms of seizure spread in epilepsy.

Amygdala↗
PubMed1991

Evaluation of an interleukin-1 receptor antagonist in the rat acetic acid-induced colitis model.

The anti-inflammatory activity of the IL-1 receptor antagonist, IL-1ra, was evaluated in the acetic acid (HOAc)-induced model of colitis in rats. Animals treated with 10 mg/kg IL-1ra or vehicle were evaluated for general health, acute phase response, and colonic in flammation 24 hours after the initiation of inflammation. A significant decrease in the accumulation of neutrophils in the colonic mucosa as measured by myeloperoxidase activity was seen in animals with HOAc induced colitis that were treated intraperitoneally with IL-1ra when compared to animals with colitis that had been treated with vehicle. IL-1ra also reduced colonic necrosis measured grossly, although there was no effect on the histology IL-1ra had a modest effect on the HOAc-induced acute phase response, as indicated by changes in the serum iron, albumin and transferrin, but the results were not statistically significant. The number of circulating erythrocytes and neutrophils was significantly increased in animals with HOAc-induced colitis and treated with IL-1ra, suggesting that IL-1ra under these experimental conditions inhibited the migration of neutrophils to the injured colon and also the overall intestinal necrosis in the colon as assessed by gross pathology. IL-1ra may be useful as an intestinal anti-inflammatory agent.

Acetates↗
PubMed1991

High incidence of contact dermatitis in leg-ulcer patients--implications for management.

A retrospective review of patch test results from all new patients with venous leg ulcers was performed for the preceding 11 months. Eighty one patients referred from general practitioners and district nurses with venous stasis ulcers were included. Positive patch tests were found in 54 patients (67%), including a continued high incidence of allergy to lanolin and topical antibiotics. Multiple allergies were found in 48 patients (58%). In addition, a new problem of allergy to cetearyl alcohol, a constituent of commonly used creams and paste bandages, was identified in 13 patients. There is a continuing high incidence of contact sensitivity in patients with venous stasis ulcers which has important implications for the management of these patients.

Anti-Bacterial Agents↗
PubMed1991

Pemphigus and the terminal hair follicle.

The scalp is frequently involved in the autoimmune skin disease pemphigus. This study demonstrates the distribution of pemphigus antigen in the scalp terminal hair follicle; as well as being found in the epidermis, it is distributed throughout the whole hair follicle outer root sheath and in the dermal bulb matrix cells. The increase in volume of target antigen offered by the follicular epithelium could be a factor determining scalp involvement in pemphigus.

Adult↗
PubMed1991

Direct instruction in math word problems: students with learning disabilities.

This investigation was conducted to test the effectiveness of strategy teaching and sequencing practice problems in teaching students with learning disabilities to identify the correct algorithm for solving addition and subtraction word problems. Sixty-two students were assigned to one of three experimental groups: strategy plus sequence, strategy only, and sequence only. The results indicated that students in the strategy-plus-sequence group, as well as those in the strategy-only group, scored significantly higher than did students in the sequence-only group. Findings indicated that strategy teaching was the more effective of the two instructional components. Implications are discussed in terms of instructional design for students with learning disabilities.

Achievement↗