Biomedical subjects
Publications and source records attributed to V Zaman.
Scanning electron microscopy studies of adult Setaria cervi male worms showed the presence of horn-like lateral appendages and characteristic striated bands on the ventral side of the tail. All other features were indistinguishable from other members of the genus Setaria.
Endoscopic biopsies of antral mucosa from 26 patients with Helicobacter pylori-associated gastritis were studied by electron microscopy (EM). Scanning electron microscopy (SEM) showed clustering of H. pylori in the intercellular areas, being entrapped by the microvilli which were decreased at the sites where the bacilli were seen. The observations of SEM were confirmed by transmission electron microscopy (TEM), which showed adherence of the bacilli to the cell surface, producing cup-shaped depressions in the epithelial cells, and occasionally intracellular infiltration by H. pylori. There were also depletion of mucus granules, degenerative changes, and disruption of intercellular junction complexes of the epithelial cells. Post-treatment biopsies showed complete disappearance of the bacilli, and ultrastructural changes associated with H. pylori infection were resolved.
Gastric cellular and humoral immune response investigated by immunoperoxidase staining of 53 antral biopsies showed significant differences in Campylobacter pylori-associated gastritis as compared with non-bacterial chronic gastritis and normal controls. IgA, secretory component, and complement C3 coated bacilli were seen in all cases of active chronic gastritis. C3 was always associated with coating by IgA, IgM, or both, which were rarely seen in gastritis without polymorphonuclear neutrophil infiltration. Intraepithelial mononuclear cellular infiltration was seen in 18 of 26 cases of C. pylori-associated chronic gastritis. The intraepithelial mononuclear cells stained positively for T cells and histiocytes.
Adults, infective larvae and microfilariae of Brugia malayi have been examined in the scanning electron microscope. In adult males the long spicule is solid with a spatulate anterior end. The small spicule is hollow and has a cup-like structure at the distal end which is covered by a hood. The infective larvae have dome-shaped caudal papillae, each with a gutter-like structure surrounding its base. The microfilariae are annulated with a distinct tail and a conspicuous hook at the cephalic end. These studies show that scanning electron microscopy of filariids can reveal features useful not only for distinguishing between species but also for understanding the functions of various organelles.
Ultrastructure of Brugia malayi egg shell and microfilarial sheath have been compared. They are identical in appearance, thus confirming that the microfilarial sheath is derived from the egg shell. The surface of the egg shell and the microfilarial sheath have distinct electron-dense projections which may have a protective role for the parasite.
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A comparative scanning electron microscopy of the infective (third stage) larva of Wuchereria bancrofti and Brugia malayi revealed the following features: The lateral caudal papillae in both species are rounded and the terminal papilla is relatively pointed and smaller. The caudal papillae in W. bancrofti are more protruding while in B. malayi they are flattened. The lateral caudal papillae in B. malayi have an indentation around their bases which is absent in W. bancrofti. This is the most useful distinguishing feature and easily recognizable. The oral opening and the cephalic papillae in both the species are similar and not useful for differentiation.
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Trichuris trichiura was examined in the scanning electron microscope and revealed a double row of sucker-like structures at the anterior part. It is postulated that they may support the attachment of the worm in host tissues. The sheath of the spicule is covered with spikes and the vulval opening is surrounded by an elevated rim-like structure with indentations.
Similar HLA association was found in patients with elephantiasis in Sri Lankans and Southern Indians. HLA-B15 was observed in 13/44 (30%) Sri Lankan patients with elephantiasis compared to 1/27 (4%) Sri Lankan controls (p = .0058; RR = 10.9) and in 5/8 (28%) Southern Indian elephantiasis compared to 10/101 (10%) Southern Indian controls (p = 0.04; RR = 3.5). In combining the data, the significance of the difference of the frequency of B15 between patients with elephantiasis and controls was even more marked (p = 0.00045; corrected p = 0.012; RR = 4.4).
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Infective larvae of Wuchereria, Brugia, Breinlia, Dirofilaria and Setaria species from an experimental vector, Aedes togoi, are compared. The distinctive bubble-like caudal papillae of Wuchereria bancrofti are readily distinguishable from the protuberant ones of Brugia spp; the 'ear-like' papillae of Breinlia are distinct from the 'knob-like' ones of Dirofilaria or the 'thorn-like' terminal papilla of Setaria.
Human and monkey leucocytes in serum from previously patent Brugia malayi infected monkeys adhered to and caused cytotoxicity to microfilariae of B. malayi in vitro. The phenomenon also occurred in human serum from confirmed cases of bancroftian and malayan elephantiasis. Adherence of leucocytes was not seen in serum from uninfected monkeys, monkeys with patent B. malayi infection and serum from rats infected with Breinlia booliati but now amicrofilaraemic. Immune serum failed to promote adherence of leucocytes to L3 of B. malayi. The activity was lost when the serum was either incubated with Protein A-bearing Staphylococcus aureus or heat inactivated at 56 degrees C for 30 min. Light and electron microscopic observations regarding the type of adhering cells and sequence of events following adherence are described.
The in vitro effect of immune monkey serum on microfilariae of Brugia malayi was investigated using the electron microscope. The sheaths of microfilaria incubated with immune serum were seen to be covered with electron dense precipitates. After 24 hours of incubation, majority of microfilariae incubated with immune serum exhibited degenerative changes. Comparable changes were not seen in microfilariae incubated with normal serum. The significance of these observations are discussed.
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Seventy-eight microfilaraemic patients with Wuchereria bancrofti and Brugia malayi infections were treated with various oral levamisole hydrochloride total dosage regimes of 150 to 3,150 mg and total diethylcarbamazine citrate (DEC) of 36 and 126 mg per kg body-weight. Significant microfilaricidal and probable macrofilaricidal effects were seen at total levamisole hydrochloride dosages of 300 to 3,150 mg and the DEC dosages. The optimum dosage regime with levamisole hydrochloride recommended for treatment of microfilaraemic patients is 100 mg initially followed by 100 mg twice daily for 10 days. This dosage regime was as effective as a total oral dosage of DEC at 126 mg per kg body-weight. Side reactions were dose-dependent, mild and transient, with fever being the most common. One patient developed fits after 150 mg levamisole hydrochloride. The pathophysiology of these side reactions is discussed and it is recommended that levamisole hydrochloride, as a probable alternative for the treatment of patent and occult filariasis, should be used only under close medical supervision.