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Biomedical subjects

B Berra

Publications and source records attributed to B Berra.

At least 73 records · Page 4Linked to original sources
PubMed1977

High performance thin layer chromatography of neutral and acidic glycolipids: application to the chemical diagnosis of lipid storage diseases.

A new technique was utilized for the separation of neutral and acidic glycolipids using an equipment named U-Chamber System. This technique was employed for the chemical diagnosis of inherited inborn errors diseases in which complex glycolipids are involved. Results in the identification of storage products in Tay-Sachs' disease, GM1 gangliosidosis and Fabry's disease are presented.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Gangliosides, sialoglycoproteins and glucocerebroside in the spleen and bone marrow of patients with beta-thalassemia major.

Bone marrow and spleen samples were studied biochemically to elucidate the nature of the material stored in the large histiocytes present in beta-thalassemic patients. Only the protein-bound N-acetylneuraminic acid (NANA) content of the spleen of homozygous beta-thalassemic patients was significantly higher than that of controls. In the bone marrow, which contained a large number of thalassemic storage cells, the lipid-bound NANA and the glucocerebroside showed a moderate increase, while the amount of protein-bound NANA was much greater than that in controls. These results, in agreement with ultrastructural and histochemical observations, differentiate thalassemic storage cells from other storage cells found in diseases characterized by an increased destruction of blood cells and suggest that there may also be an impairment of the sialoglycoprotein metabolism of the red blood cells in homozygous beta-thalassemia.

Adolescent↗
PubMedDate not supplied

Increased tumorigenicity and invasiveness of C6 rat glioma cells transfected with the human alpha-2,8 sialyltransferase cDNA.

Gangliosides are thought to be involved in tumor cell proliferation, migration and invasiveness as so far demonstrated by the addition of exogenous gangliosides to the culture medium. To better understand the direct influence that alterations in ganglioside synthesis can exert on these functional aspects of cell biology, in the present study, we investigated the behaviour of C6 rat glioma cells after stable transfection with the human CMP-NeuAc:NeuAcalpha2-3Galbeta1-4GlcCer alpha2,8-sialyltransferase (SAT-II, EC 2.4.99.8) gene. The enzyme synthesizes ganglioside GD(3) by adding a sialic acid residue to ganglioside GM(3). Stable transfection of the constructs into C6 cells and expression of the human SAT-II gene were evaluated using PCR and RT-PCR amplification, respectively. Qualitative and quantitative analysis of the ganglioside profile was performed by conventional HP-TLC and identity of de novo synthesized species was assessed by TLC immunostaining. Results show that whereas C6 parental cells and C6 cells transfected with the empty expression vector synthesize, almost exclusively, ganglioside GM(3), de novo synthesis of GD(3) is clearly observed in clones expressing the alpha2,8-sialyltransferase. Subcutaneous grafting in athymic nude mice of cells expressing high levels of GD(3) induces tumors growing faster and more aggressively than controls. In in vitro assays, the same cells demonstrate increased proliferation rate, motility and invasiveness. Chemotaxis and chemoinvasion were assayed using the modified Boyden chamber. Data obtained suggest that endogenously neosynthesized GD(3) is able to modify proliferation rate, motility and invasion of C6 rat glioma cells, enhancing the features of malignancy of this tumor cell line.

Animals↗
PubMedDate not supplied

Usefulness and potential pitfalls of sialic acid determination in sera of patients with ovarian tumors.

Increasing evidence in the literature indicates that serum sialic acid is increased in cancer patients suggesting a possible usefulness of its determination as a tumor marker. However there are many discrepancies in the data reported, probably due to methodological errors, mainly in lipid bound sialic measurement. In this paper we illustrate the results obtained when we applied a method worked out in our laboratory for the determination of total and fractionated sialic acid (lipid and protein bound) to the analysis of sera from patients with ovarian tumors and the preliminary data on the follow up of selected cases. The potential pitfalls in using this relatively new tumor marker will be critically evaluated.

Adenocarcinoma↗
PubMedDate not supplied

A new procedure for gangliosidic N-acetylneuraminic acid analysis in serum.

In this paper a method is presented which is suitable for the extraction, purification and analysis of serum gangliosides. The advantage in comparison with other previously published procedures is the complete extraction of sialoglycolipids without contamination of sialoglycoproteins and/or sialoglycopeptides. The method could be used as a second-level test for the diagnosis and follow-up of cancer patients, and also could be potentially used for pharmaco-kinetic studies after ganglioside treatment.

Chloroform↗
PubMedDate not supplied

[Absorption, distribution, excretion and metabolism of 4-carbomethoxythiazolidine chlorohydrate. Biochemical experimental study in the rat].

A biochemical-metabolic study has been conducted on TCM (4-carbomethoxythiazolidin hydrochloride) in rats, utilising a product traced with 14C. An in-vitro test has demonstrated that TCM is hydrolised by endogenous esterases to thiazolidincarboxylic acid, into the following decreasing order of activity: kidneys, lungs, plasma, liver, intestinal content and mucosa. Upon oral administration, TCM proved to have a good and rapid absorption and distribution level in the organs. In the beginning the liver and the kidneys have displayed higher concentrations with respect to the lungs; after 8 hours, however, the latter have displayed slightly lower concentrations than before, which were not very far from the liver's and kidneys'. TCM has been mainly eliminated through the urines (56.9% in 24 hours) and less through the feces (6.7% in the same period of time). By means of a thin-layer chromatography analysis and a mass-spectrometry it has been possible to study the metabolism of TCM. The results of both in-vitro and in-vivo tests have demonstrated that TCM is hydrolised to thiazolidin-carboxylic acid, which, in its turn, is transformed into cysteine. This last transformation does mainly occur in the liver, but significantly in the lungs as well. TCM is absorbed in part as such and in part as thiazolidincarboxylic acid. As no methyl-cysteinate has been traced, it has been assumed that the hydrolysis of the ester bond was a kinetically quicker event than the heterocycle opening.

Animals↗