Biomedical subjects

A N Nasr

Publications and source records attributed to A N Nasr.

At least 19 recordsLinked to original sources

PubMed2001

Lentiginous macules and patches of neurofibromatosis (an approach to better terminology).

BACKGROUND AND OBJECTIVES: Freckles (ephelides) are small, light brown macules of sun-exposed areas in fair-skinned subjects. On the other hand, freckle-like pigmentation of the axilla is a highly characteristic feature of neurofibromatosis. To what extent (clinically and pathologically) are the two pigmentary defects similar? And to what extent are café-au-lait patches and freckle-like lesions similar pathologically? SUBJECTS AND METHODS: Ten cases of neurofibromatosis and 10 cases of freckles were examined clinically. Two biopsies were taken from the former; one obtained from an axillary freckle-like lesion, and the other from a café-au-lait patch. One biopsy only was taken from freckles. The biopsies were processed for haematoxylin and eosin, silver stain and transmission electron microscopy. RESULTS: Obvious differences were detected between freckles (ephelides) and freckle-like lesions in cases of neurofibromatosis. Café-au-lait patches and freckle-like lesions showed the same pathological changes of lentigo simplex, with increased melanin pigment from the basal layer up to the stratum corneum, moderate elongation of the rete ridges and mild inflammatory infiltrate intermingled with melanophages. Electron microscopy revealed an increase in melanocyte number and the presence of giant melanin granules in freckle-like pigmentation as well as café-au-lait patches. These ultrastructural freckles (ephelides) showed an increase in activity but not the number of melanocytes. CONCLUSIONS: The term freckle-like should be changed to lentiginous macules of neurofibromatosis. On the other hand, the café-au-lait patches should be considered as lentiginous patches. Freckles should be restricted to sun-exposed areas in fair-skinned persons only.

Adolescent↗

PubMed1996

Corneocytes in scaly parakeratotic diseases.

BACKGROUND AND OBJECTIVES: The stratum corneum of some of the scaly (parakeratotic) diseases was examined with light and scanning electron microscopy (SEM) with the purpose to reveal the importance of this layer in the diagnosis of some of the diseases associated with the formation of scales. MATERIALS AND METHODS: Two biopsies of the skin surface were taken: one, obtained from 80 patients with various parakeratotic scaly diseases and from 25 control subjects, was processed for light microscopy; the other biopsy for SEM was taken from 10 control subjects and 25 patients. The diagnoses of these patients were: psoriasis (5 patients), erythrodermic psoriasis (2 subjects), parapsoriasis (5 patients), pityriasis rubra pilaris (5 subjects), pityriasis rosea (3 subjects), and seborrheic dermatitis (5 subjects). RESULTS: The light microscopic studies showed that normal corneocytes are of polygonal shape with their largest diameter measuring 42 microns; these cells lacked nuclei. All parakeratotic cells appeared bizarre in shape, smaller than normal, and the cells contained a nucleus. With SEM, normal cells appeared relatively regular in size and shape, trabeculated, and had a flat surface. Cells examined in all the diseases revealed various sizes, outlines, and trabeculae. Specific surface patterns (print) of diseased cells were: "fish-scale" in psoriasis; "marbled" in parapsoriasis, "rocky stone" in pityriasis rubra pilaris; "heart-shaped" in seborrheic dermatitis, and semicrystalloid in pityriasis rosea. CONCLUSIONS: Parakeratosis is characterized not only by the retention of the nucleus in keratinocytes, but is also characterized by a cell of smaller size. The specific print of a disease helps in the diagnosis. The print will change with different stages of a disease.

Biopsy↗

PubMed1995

The role of mast cells in treatment of scabies.

OBJECTIVE: The purpose of this study was to recognize the role of mast cells in the pathogenesis of scabies. METHODS: One hundred and fifty patients and 10 controls were included in the study. Group 1 included 20 patients without previous treatment. In group 2, 80 patients were treated with antiscabietic drugs. Group 3 had 50 patients who received an antiscabietic drug followed by 3 days of crotamiton. Diurnal and nocturnal skin biopsies were taken from group 1. In groups 2 and 3, the biopsies were taken after 2 weeks of treatment. Sections were cut and stained by hematoxylin and eosin and Giemsa stains. RESULTS: Mast cells were increased in diurnal and nocturnal biopsies. Evident degranulation of mast cells was detected in nocturnal biopsies. The mast cell number decreased to half its pretreatment number in patients treated with antiscabietic drugs and to its normal number in patients treated with antiscabietic drugs followed by 3 days with crotamiton. CONCLUSION: The number of mast cells are increased in scabietic lesions. This plays a role in the pathogenesis of the clinical and histologic picture of scabies. We recommend that an antiscabietic drug should be followed by 3 days of crotamiton in the treatment of scabies.

Administration, Cutaneous↗

PubMed1992

Histopathological and histochemical studies on the sigmoidal and rectal tissues of hepatosplenic children with gastro-intestinal troubles.

Hepatosplenomegaly accompanied with different intestinal troubles is more or less a marked clinical manifestations in children. The histopathological and histochemical changes were studied in biopsied materials taken from the sigmoidal and rectal tissues of 49 children. These children had schistosomiasis mansoni (26), schistosomiasis and amoebiasis (4), schistosomiasis and tuberculosis (TB.) (2), amoebiasis (4), thalassemia (6), acute myeloid leukaemia (AML) (1), mucopolysaccharidosis (1) and bacillary dysentery (5). The pathological changes were erosion ulceration hyperplasia, atrophy, crypt-abscess and fibrosis (mucosa) and oedema, congestion, cellular infiltration (Lamina propria). The chemical changes were the mucin secretion, deposition of collagen and fibrin and activity of the argentaffin cells. Not all the disease agent had the same effect, but changes were marked mainly in children with S. mansoni and/or E. histolytica.

Child↗

PubMed1992

Myopathic changes in schistosomal hepatosplenomegaly; histopathological, histochemical and immunopathological studies.

Eighteen patients suffering mainly from schistosomal hepatosplenomegaly (B.H.S.M.) were selected & classified into 3 groups according to the degree of B.H.S.M. Muscle biopsy for histopathological, histochemical and immunopathological studies were taken. The results showed that fatiguability as a symptom was present in all cases but motor weakness was present in four cases. Twelve cases had peripheral neuropathy in the form of glove and stocking hypothesia, while pyramidal tract lesion was present in four cases. Two cases, however, showed both peripheral neuropathy and pyramidal tract lesions. Histopathological and histochemical assessment revealed frank myopathic changes in 14 cases while only one case showed definite neuropathic changes. The remainder cases were inconclusive. Immunopathological examination revealed marked deposition of IgG in 50% of cases, while IgM and IgA showed mild to moderate reactions. It was concluded that muscular changes in schistosomal patients are myopathic in nature and that immunological mechanisms could be considered as a factor in the pathogenesis of this muscular disorder.

Adolescent↗

PubMed1990

Riedel's thyroiditis. Case report.

A case of Riedel's thyroiditis in a young euthyroid man is presented. The diffusely enlarged and uniformly hard gland extended laterally beyond the sternomastoid muscles. Aspiration cytology suggested malignancy. Isthmectomy with excision of 50% of the fibrous gland and clearance of two-thirds of the tracheal circumference gave a good result.

Adult↗

PubMed1977

Toxic neuropathy--an overview.

The involvement of the nervous system in systemic intoxication offers diagnostic and investigative challenges to the occupational health team. Often early evidence of neurotoxicity is vague, of a highly subjective nature and may be complicated by the presence of neuropathies due to other causes such as diabetes mellitus or exposure to multiple neurotoxins such as lead and solvents. The variety of agents producing neurotoxicity is wide, including heavy metals, organophosphates, acrylamide and its analogs, industrial solvents, therapeutic agents and plant alkaloids. The identification of neurotoxic substances requires well controlled epidemiologic studies of humans, including electrodiagnostic testing and well planned experimental animal studies. The latter include consideration of choice of animal species, routes of administration, duration of exposure, clinical evaluation, electrodiagnostic testing, morphologic description of the damage produced and its distribution, and the recognition of the potential for intercurrent naturally occurring neuropathologic processes. The aim of this discussion is to give an overview of these and other factors involved in the assessment of a neurotoxic potential.

Animals↗

PubMed1971