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Biomedical subjects

H M Khalil

Publications and source records attributed to H M Khalil.

At least 55 records · Page 3Linked to original sources
PubMed1982

Alkaline phosphatase-positive Langerhans cells in the epidermis of cattle.

Dendritic alkaline phosphatase-positive cells in the epidermis of cattle were studied. By light microscopy they were shown to occur in basal and suprabasal positions in the epidermis, with their dendrites reaching into outer layers of the stratum spinosum. They were also found in the external root sheaths of hair follicles. In separated epidermal sheets from ears of cattle these cells were found to be uniformly distributed with an average concentration of approximately 1,600 cells/mm2. Langerhans cells were identified in the epidermis by the presence of dendritic cells of Langerhans cell granules, a lobated nucleus and clear cytoplasm and the absence of desmosomes, tonofilaments, premelanosomes, and melanosomes. Alkaline phosphatase activity was associated with the plasmalemma of such cells and occasionally with cytoplasmic inclusions which may have been Langerhans cell granules. Enzyme activity was not associated with melanocytes or keratinocytes. It is confirmed that alkaline phosphatase activity is a feature of Langerhans cells, and possibly "indeterminate" cells in the normal epidermis of cattle.

Alkaline Phosphatase↗
PubMed1981

Gross and histological studies of immediate, Arthus, and delayed skin test responses to schistosome antigen, and of delayed response to ubiquitous antigens in Egyptians.

Gross studies of skin reactions to adult antigen of Schistosoma mansoni were made on 156 hospitalized patients with schistosomiasis and 114 subjects from the nonendemic area of Hurghada in Egypt. Wheal areas equal to or greater than 1.0 cm2 indicated a positive immediate (15-min) reaction to adult worm antigen; the criterion of positivity for both 24-hour and 48-hour delayed reactions was an area of induration equal to or greater than 0.6 cm2. Immediate reactions with adult worm antigen were observed in 99% of the patients with schistosomiasis and 11% of the subjects from Hurghada: the percentages with delayed reaction were 58% and 2%, respectively. Biopsies of skin test sites at various intervals after antigen injection were done on 87 individuals. Eosinophilic and mononuclear infiltrates were characteristic of immediate and delayed skin responses, respectively. Biopsies from 22 patients with marked skin reactions 5 hours after antigen injection showed that a neutrophilic response indicative of Arthus reactivity was present in only 18. Thus, Arthus reactivity could not be determined on gross appearance alone. The studies did not show any evidence of delayed basophilic hypersensitivity to schistosome antigen. Immunofluorescent studies on a small number of biopsies suggested that a late phase (5-hour) reaction due to IgE may occur in some patients. Delayed reactivity to mumps and/or monilia skin test antigens was observed in 91% of Egyptians in a nonendemic area of schistosomiasis. Delayed hypersensitivity to PPD was detected in 44% of the same group.

Adolescent↗
PubMed1979

Langerhans cells trap tick salivary gland antigens in tick-resistant guinea pigs.

In the infested skin of tick-resistant guinea pigs, indirect immunofluorescence techniques have revealed that antigens from the ticks' salivary glands are associated with discrete dendritic cells in the epidermis. Evidence is presented to support the suggestion that these antigen-retaining cells are Langerhans cells.

Adenosine Triphosphatases↗
PubMed1979

The location of tick salivary antigens, complement and immunoglobulin in the skin of guinea-pigs infested with Dermacentor andersoni larvae.

Using indirect immunoflorescence techniques, tick salivary gland antigens (SGA) were demonstrable in cement deposited on the skin by ticks and in all layers of the epidermis of infested guinea-pigs close to the sites where ticks attached. The antigen remained in these sites for several days after ticks had detached. In tick-resistant but not in normal guinea-pigs, SGA, complement and IgG were deposited at the dermo-epidermal junction even at some distance from the attachment site. Complement was also demonstrable in epidermal vesicles which developed beneath larvae attached to resistant guinea-pigs. It is suggested that antigen-antibody reaction and complement activation at these sites may play a role in the development of skin lesions and the attraction of basophils to these areas in challenged tick-resistant guinea-pigs. Tick antigens were also found to be associated with dendritic suprabasal cells in the epidermis of resistant guinea-pigs. It has previously been proposed that such SGA-trapping cells are Langerhans cells. These cells, in the presence of specific antibody and complement, could also initiate epidermal lesions in resistant guinea-pigs.

Animals↗