Direct enzyme-linked immunosorbent assay: a simple immunoassay using Leishmania donovani promastigote for diagnosis of kala-azar

For immunodiagnosis of kala-azar enzyme-linked immunosorbent assay (ELISA) and immunofluorescence testing (IFAT) are commonly used. In IFAT, whole parasite antigen and in ELISA the soluble antigen have been used. Preparation of ELISA antigen has certain inherent difficulties. We have developed a simple, specific, and quantitative immunoassay, "direct ELISA" for diagnosis of kala-azar. Intact formalinized promastigote suspension has been used to combine with the antibodies of the patient sera. The colour developed in the supernatant by the enzyme conjugate combined on the parasite surface was measured with a spectrophotometer. The test was able to detect kala-azar-specific antibodies at very high serum dilution and could discriminate between kala-azar and the common diseases prevalent in Asia. The optical densities of the sera of different control groups were significantly low. The method has potential for use as a diagnostic tool in less well equipped laboratories.

Gastric carcinoma in a child associated with nodular lymphoid hyperplasia of the colon

We report a 12 year old boy of Nepalese origin with gastric adenocarcinoma and associated nodular lymphoid hyperplasia of the colon, with hemoglobin E trait and normal serum immunoglobulins. The boy underwent a curative resection and is free of recurrence or metastasis nine months after diagnosis.

A novel tubulin from Mimosa pudica. Purification and characterization

From Mimosa pudica fresh leaves and pulvinar callus cells, we have purified tubulin protein using an anion-exchange resin, DEAE-Sephadex A-50, followed by ammonium sulfate fractionation and Sephadex G-200 gel filtration. The purified protein consisted of alpha and beta subunits and trace quantities of other proteins. When analysed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis at pH 8.8, both alpha and beta subunits of tubulin almost comigrated with their counterparts from goat brain. Two-dimensional electrophoresis revealed that this tubulin contains one major alpha-tubulin having a pI value of 7.1 and three beta species having pI values of 6.70, 6.46 and 6.40. Morphologically normal microtubules were observed by electron microscopy; self-polymerization in vitro, even in the cold, can also be achieved. Radioimmunoassays, and also immunoblotting with the antibodies raised against alpha- and beta-tubulins of this plant, showed that the nature of alpha-tubulin is different from that obtained from other sources. This is an example of plant tubulin where strong colchicine binding at 1 microM was observed. This protein constitutes 5-6% of the total extractable protein in the leaves. We propose that movement of the leaves of this plant may be regulated by the presence of a high amount of this protein.

Cronkhite-Canada syndrome with hypothyroidism

An elderly man with non-familial gastrointestinal polyposis, malabsorption and progressive hypoproteinemia is reported. Associated alopecia, cutaneous hyperpigmentation and nail dystrophy with loss of nails were consistent with the diagnosis of Cronkhite-Canada syndrome. Hypothyroidism was present in this patient and the rare association of these two conditions is discussed.

Ultrasonographic evaluation of carcinoma of the gall bladder

Out of 6018 patients who were evaluated ultrasonographically for gastrointestinal problems over a four-and-a-half year period, 201 patients with a mean age of 53 years were diagnosed to have carcinoma of the gall bladder (3.3%). In 191 of these the diagnosis was confirmed by laparotomy and histopathological examination and in 3 other patients ultrasound guided fine needle aspiration cytology yielded malignant cells. In the remaining 7 patients the diagnosis was not confirmed by tissue examination-3 had metastases and 4 refused further investigation. Two sets of features were detected on ultrasonography: type I-a mass occupying the gall bladder fossa and obliterating the lumen (144 patients), and type 11-a polypoid lesion projecting into the gall bladder lumen (57 patients). Gallstones were present in 157 patients (78%) but more often in patients with the type I features. Associated ultrasonographic features such as liver and lymph node involvement, dilatation of intrahepatic bile ducts and ascites were also assessed. We conclude that abdominal realtime ultrasonography is a reliable method for diagnosing carcinoma of the gall bladder.

An ELISA for quantitation of tetanus toxin

A sandwich ELISA for quantitation of tetanus toxin was devised using commercially available horse antitetanus antiserum and its HRP-conjugate. With commercial toxoid as a standard the assay had a lower sensitivity of 100 ng/ml and was linear up to 100 micrograms/ml. In terms of Lf equivalents the ELISA assay was linear from 0.02 to 20 Lf/ml. The Lf activity in 20 preparations of tetanus toxin as determined by ELISA was comparable to the activity measured by conventional flocculation tests (r = 0.987).

In vitro organogenesis and somatic embryogenesis from leaf explants of Leucosceptrum canum sm

Plantlets were obtained from leaf explants of a Labiatae tree - Leucosceptrum canum Sm. using plant tissue culture techniques. Two types of calli proliferated from the leaf explants when grown on different media, one of which was amenable to somatic embryogenesis. Differentiation of the embryoids started from the fourth passage of culture and continued up to the seventh passage. The number of embryoids decreased with the age of the callus. The capacity of such embryoids to form entire plantlets was studied using different nutrient mileux. Embryoids formed plantlets on Murashige and Skoog's (MS) medium fortified with benzylaminopurine plus indolebutyric acid. Organogenesis was observed in shoot-buds derived from explants of in vitro regenerated plantlets on MS basal medium supplemented with benzylaminopurine. Culture regenerated plantlets were transferred to MS medium without sucrose and growth hormones; finally transferred to pots containing sterile vermiculite where they are growing.