Browsing by Author "Mall, Anwar S"

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    Gastric remnant carcinoma : histochemical and immunohistochemical profile
    (2004) Elazzabi, Tawfik; Mall, Anwar S
    Gastric remnant carcinoma (GRC) is a gastric cancer that develops in gastric remnant more than five years after resection for benign disease. GRC comprises 1 %-9% of all gastric cancers. Partial gastrectomy for peptic ulcer is thought to be a risk factor for GRC. Pancreato-duodenal and bile reflux may play an important part in the aetiology of GRC. Primary gastric carcinoma (pGC) is a gastric cancer that arises in un-operated stomach and chronic gastritis is a well-known risk factor. Consequently there appear to be differences in the aetiology of GRC and PGC. According to many studies, surgical treatment of early GRC (Stage I or II) resulted in the same or better prognosis with similar stage PGC. However if diagnosed late, GRC has a worse prognosis than PGC at the same stage. In this study haematoxylin and eosin, alcian blue pH 2.5, periodic acid Schiff, high iron diamine and Giemsa stains as well as immunohistochemical methods (eight antibodies against MUCI to MUC6) were used to determine the type of mucin and the pattern of staining in twenty cases of GRC and twenty PGC (ten cases of intestinal type PGC, ten diffuse type PGC) and ten normal gastric mucosal biopsies. The aim of the study was to describe the morphology of GRC and the adjacent gastric mucosa, as well as to determine the histochemical and immunohistochemical mucin profile of GRC and to compare this with that of PGC and normal mucosa.
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    Mucus and Mucins: do they have a role in the inhibition of the human immunodeficiency virus?
    (BioMed Central, 2017-10-06) Mall, Anwar S; Habte, Habtom; Mthembu, Yolanda; Peacocke, Julia; de Beer, Corena
    Background: Mucins are large O-linked glycosylated proteins which give mucus their gel-forming properties. There are indications that mucus and mucins in saliva, breast milk and in the cervical plug inhibit the human immunodeficiency virus (HIV-1) in an in vitro assay. Main body of abstract: Crude mucus gels form continuous layers on the epithelial surfaces of the major internal tracts of the body and protect these epithelial surfaces against aggressive luminal factors such as hydrochloric acid and pepsin proteolysis in the stomach lumen, the movement of hard faecal pellets in the colon at high pressure, the effects of shear against the vaginal epithelium during intercourse and the presence of foreign substances in the respiratory airways. Tumour-associated epitopes on mucins make them suitable as immune-targets on malignant epithelial cells, rendering mucins important as diagnostic and prognostic markers for various diseases, even influencing the design of mucin-based vaccines. Sub-Saharan Africa has the highest prevalence of HIV-AIDS in the world. The main points of viral transmission are via the vaginal epithelium during sexual intercourse and mother-to-child transmission during breast-feeding. There have been many studies showing that several body fluids have components that prevent the transmission of HIV-1 from infected to non-infected persons through various forms of contact. Crude saliva and its purified mucins, MUC5B and MUC7, and the purified mucins from breast milk, MUC1 and MUC4 and pregnancy plug cervical mucus (MUC2, MUC5AC, MUC5B and MUC6), inhibit HIV-1 in an in vitro assay. There are conflicting reports of whether crude breast-milk inhibits HIV-1 in an in vitro assay. However studies with a humanised BLT mouse show that breast-milk does inhibit HIV and that breast-feeding is still advisable even amongst HIV-positive women in under-resourced areas, preferably in conjunction with anti-retroviral treatment. Conclusion: These findings raise questions of how such a naturally occurring biological substance such as mucus, with remarkable protective properties of epithelial surfaces against aggressive luminal factors in delicate locations, could be used as a tool in the fight against HIV-AIDS, which has reached epidemic proportions in sub-Saharan Africa.
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    The role of crude human saliva and purified salivary MUC5B and MUC7 mucins in the inhibition of Human Immunodeficiency Virus type 1 in an inhibition assay
    (BioMed Central Ltd, 2006) Habte, Habtom H; Mall, Anwar S; de Beer, Corena; Lotz E, Zoe; Kahn, Delawir
    BACKGROUND: Despite the continuous shedding of HIV infected blood into the oral cavity and the detectable presence of the AIDS virus at a high frequency, human saliva is reported to inhibit oral transmission of HIV through kissing, dental treatment, biting, and aerosolization. The purpose of this study was to purify salivary MUC5B and MUC7 mucins from crude saliva and determine their anti-HIV-1 activities. METHODS: Following Sepharose CL-4B column chromatography and caesium chloride isopycnic density-gradient ultra-centrifugation, the purity and identity of the mucins was determined by SDS-PAGE and Western blotting analysis respectively. Subsequently an HIV-1 inhibition assay was carried out to determine the anti-HIV-1 activity of the crude saliva and purified salivary mucins by incubating them with subtype D HIV-1 prior to infection of the CD4+ CEM SS cells. RESULTS: Western blotting analysis confirmed that the mucin in the void volume is MUC5B and the mucin in the included volume is MUC7. The HIV inhibition assay revealed that both the crude saliva and salivary MUC5B and MUC7 mucins inhibited HIV-1 activity by 100%. CONCLUSION: Although the mechanism of action is not clear the carbohydrate moieties of the salivary mucins may trap or aggregate the virus and prevent host cell entry.