Biomedical subjects

F S Farah

Publications and source records attributed to F S Farah.

4 recordsLinked to original sources

PubMed1979

Dermopathic changes in hypozincemia.

In seven patients with chronic debilitating gastrointestinal disease who were being given total parenteral nutrition using L-amino acids and concentrated dextrose solution, severe hypozincemia (less than 60 micrograms/dL) developed with characteristic skin lesions and alopecia. The lesions were similar to seborrheic dermatitis, and they occurred in areas of high sebaceous gland concentration. Hyperkeratotic lesions were also seen on the extensor surfaces of large joints. The skin lesions and alopecia disappeared when serum zinc values were raised to levels above 60 micrograms/dL, with appropriate zinc sulfate replacement. A hypothesis on the etiology and clinical manifestations is presented.

Adult↗

PubMed1977

Postganglionic cholinergic dysautonomia.

A 9-year-old boy presented with symptoms and signs of marked postganglionic cholinergic autonomic dysfunction manifested by bilateral internal ophthalmoplegia, impaired secretion of tears and saliva, lack of gastrointestinal motility, atony of the bladder, generalized absence of sweating, and hypertension. Clinical and pharmacological studies confirmed that the abnormalities were restricted mainly to the postganglionic cholinergic autonomic system and showed evidence of postdenervation supersensitivity to parasympathomimetic drugs. The patient was treated in the early phase of his illness by the administration of carbachol, and eventually he made a slow and partial spontaneous recovery. Histoimmunofluorescent studies on a skin biopsy specimen suggested an autoimmune origin for his disease, with IgG antibodies being produced against postganglionic cholinergic autonomic fibers.

Autoimmune Diseases↗

PubMed1976

The effect of Leishmania tropica on stimulation of lymphocytes with phytohaemagglutinin.

Cell-mediated immune (CMI) responses are important in the immunity against leishmanial infections. However, infection persists in the presence of CMI for unknown reasons. Evidence is presented that L. tropica and its products are capable of inhibition of the stimulation of lymphocytes by PHA. This inhibition is dose dependent, and not dependent on competition for nutrients in the medium, nor on neutralization of PHA. The inhibition is observed on the lymphocytes of species susceptible to leishmanial infection, and not operative in resistant species. The mechanisms of the lymphocyte suppression are discussed.

Animals↗

PubMed1975

The role of the macrophage in cutaneous leishmaniasis.

The investigation of the role of the macrophage in cutaneous leishmaniasis has been prompted by observations of the clinical behaviour of the infection. In contrast to the self-healing oriental sore, chronic leishmaniasis is characterized by persistent lesions and leishmania recidiva by lesions that flare up locally long after clinical healing. In both clinical types, the parasite is thought to be maintained inside the macrophages. It will be shown that the normal macrophages of mice and guinea-pigs are parasitized by L. tropica; the parasite is not killed by the macrophages but it multiplies within these cells. Incubation of the macrophages with rabbit or human anti-Leishmania sera on the other hand, leads to the attachment of specific immunoglobulins to the macrophage cell surface and consequently to the prevention of parasitization by L. tropica under the experimental conditions. The parasite appears to be immobilized at the macrophage cell surface. Normal rabbit or human sera did not interfere with parasitization. It is postulated that the parasite specifically immobilized at the cell surface might possibly be better exposed to and affected by the immune response than intracellular parasites. Furthermore, infected parasitized macrophages contribute to the immune response by processing soluble antigens from the intracellular parasites and presenting them on their surfaces, as seen by the greater affinity (higher dilution) of anti-Leishmania antibody for the cell membrane of infected macrophages than for normal macrophages.

Animals↗