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Biomedical subjects

B Berra

Publications and source records attributed to B Berra.

At least 37 records · Page 2Linked to original sources
PubMed1997

Activities of glycolipid glycosyltransferases and sialidases during the early development of Xenopus laevis.

The activities of glycosyltransferases and sialidases, together with the ganglioside content and distribution, have been extensively studied in mammals, while the informations on tissues of other animals, including amphibian, are scarce. In this paper we present data on the activities of SAT-1, SAT-2, SAT-4, SAT-5, GlcNAcT-1, GalNAcT-1, GalT-6, and sialidases studied in Xenopus laevis embryos at different stages of development. The highest activity was found at days 4 and 5 of embryogenesis for glycosyltransferases and sialidases respectively; a tentative correlation between the in vitro activity of these enzymes and the content of neutral and acidic glycolipids is discussed.

Animals↗
PubMed1997

Prolonged in vitro culture modifies the surface lipid composition of murine melanoma cell lines.

Lipid composition of two murine melanoma cell variants (B16, without malignant properties and B16-F10, with high metastatic activity), has been examined at different stages of growth. The aim of the work was to identify cell surface modifications due to the time length of in vitro culture, that could be one variable to consider when metastatic potential is studied. Some of the analyzed parameters (ganglioside- and glycoprotein-bound neuraminic acid, cholesterol, neutral glycolipids, phospholipids, triacylglycerols) undergo statistically significant variations at the various passages in B16-F10 line. Fatty acids composition of the phospholipidic fraction was changed only at the last observed passage (100) in B16 line. No one of the examined parameters justifies the ability of B16-F10 cells to invade distant districts and to originate new tumors. Probably detailed lipid analysis on cellular subfractions, as already performed in this study on total lipid extract of the whole cell, could be a valuable tool to identify differences related with metastatic potential.

Animals↗
PubMed1996

The primary structure of UK114 tumor antigen.

UK114 is a tumor antigen expressed by various malignant neoplasms. The complete amino acid sequence of UK114 purified from goat liver has been determined by automated Edman degradation of CNBr and endoproteinase Lys-C peptides. The protein contains 137 amino acid residues. which corresponds to a molecular mass of 14,229 Da. MALDI-TOF analysis resulted in a molecular weight of 14,290, suggesting that the N-terminal Met residue is acetylated. Sequence comparison shows that UK114 from goat liver (1) has 77% identity with a previously described 23 kDa protein from rat liver (Levy-Favatier et al. (1993) Eur. J. Biochem. 212, 665-673), (2) shares a very high degree of similarity with a family of prokaryotic and eukaryotic hypothetic proteins whose function have not yet been characterized, and (3) exhibits a significant similarity to a group of tumor-associated antigens which belongs to a superfamily of heat shock proteins, acting as possible targets for the host's antitumor immunity.

Amino Acid Sequence↗
PubMed1996

Tissue and developmental specificity of a polysialo-ganglioside species in the amphibian Xenopus.

Xenopus embryos contain a considerable amount of a polysialo-ganglioside not yet fully characterized; in this paper, we will refer to it as ganglioside XI. Preliminary experiments indicate asialo-GMI as the core structure of the ganglioside XI and palmitic and oleic acid as the fatty acids of the ceramide moiety. Further analyses by comparative 2D-TLC with adult fish and chick embryo brains indicate the pentasialilated ganglioside GP1c as the possible structure of XI. In the adult Xenopus, XI characterizes the ganglioside pattern of the central nervous system while is absent in all the other tested tissues. At least two other more polar (presumably richer in sialic acid) bands are often visible under XI, both in embryos and in brain and spinal cord tissues of adult Xenopus. The persistence of polysialo-gangliosides in the brain and spinal cord of adult amphibians could serve to guarantee a proper functioning of the central nervous system at low body temperature.

Animals↗
PubMed1996

Excessive stimulation of serotonin2 (5-HT2) receptors during late development of chicken embryos causes decreased embryonic motility, interferes with hatching, and induces herniated umbilici.

The existence and functional significance of 5-HT2 receptors in chicken embryos was studied by injecting the selective agonist dimethoxyiodophenylaminopropane (DOI), alone or in conjunction with the selective 5-HT2 antagonist ritanserin (RIT), into domestic chicken eggs with embryos of varying ages. DOI caused dose-dependent reductions in hatchability and herniated umbilici in hatchlings. These effects were observed after injection early, mid, or late during embryonic development, with evidence of the toxic effects of DOI being greater in older embryos, probably due to 5-HT2 receptor activation late in development, even after injecting DOI as early as on day 3 of embryogenesis. This is based upon the fact that embryos in eggs injected with DOI early continued to develop apparently normally, failing to hatch, often after pipping their shells. Additionally, those that hatched often did so with herniated umbilici, as did late-exposed embryos, indicating that DOI's effects upon this organ were most likely mediated during the prehatching period (i.e., days 18-20). The agonist's selectivity was confirmed by the capacity of RIT to dose dependently block both of these toxic effects of DOI. Reduced embryonic motility monitored on day 19, after injection of DOI on the evening of day 18, suggests that excessive activation of 5-HT2 receptors late during development of this species interferes with some normal embryonic behaviors and physiological changes necessary for inducing and/or maintaining the hatching process.

Animals↗
PubMed1995

Infantile sialic acid storage disease: biochemical studies.

Infantile free sialic acid storage disease (ISSD), is an inherited metabolic disorder characterized by hyperexcretion of free sialic acid in the urine and by its storage in the lysosomes of different tissues. In order to obtain more reliable data on the amount of total and free sialic acid, we analyzed the urine, brain, cerebellum, liver, spleen, and kidneys from a 3-month-old baby who died with a diagnosis of ISSD. The lysosomal nature of the disease was confirmed by an electron microscopic study of cells in culture. No significant abnormalities were found involving cholesterol, total phospholipids, glycolipids, and gangliosides in the tissues examined. However, differences in the tissue distribution of individual glycolipids and gangliosides were observed. The amount of free and total sialic acid was markedly increased, due to the storage of free sialic acid accompanied by its hyperexcretion in the urine. These results demonstrate and confirm that only acid monosaccharide transport from the lysosome compartment is involved in the pathogenesis of ISSD.

Brain Chemistry↗
PubMed1995

Retinoic acid induces changes in Xenopus embryo glycolipid pattern.

Retinoic acid (RA), known for its important role in cellular differentiation, may cause a modification of glycolipid distribution characterized by a shift from globoserie towards latto- and ganglio-series. In the present paper, we have investigated the modifications of the lipidic pattern after exogenous RA treatment of Xenopus embryos. We have noticed a decrease in neutral glycolipids with a parallel increase in gangliosides; the content of sulfatides does not seem to be modified. Beside the shift toward ganglio-serie, we have also observed a redistribution inside this class of lipids. In particular, following RA treatment, the relative distribution of GD1b and GT1b increases while that of GM3 decreases.

Animals↗
PubMed1995

Glycolipid patterns during Xenopus embryo development.

Glycolipid patterns have been studied during the first six days of Xenopus embryo development. Glycolipid contents showed a sharp increase more evident after the third day of development. Glucosylceramide and sulphatide are not only the most represented species, but also those which exhibit a statistically significant percentage change during early development. Among gangliosides, GD3 is the most represented specie. Two polysialylated gangliosides with not yet established structures are also present.

Ammonia↗
PubMed1995

Phospholipid distribution and fatty acid composition in different brain regions during chick embryo development.

The phospholipid profile of different chick embryo brain regions was studied from 11 to 21 days of development, revealing interesting changes in content and distribution. Total phospholipid phosphorus (P), in micrograms of P per microgram of DNA, increases significantly during development of cerebral hemispheres (CHs), optic lobes (OLs), and brainstem (BS). Compared with CH and OL, the BS shows at all stages a significantly higher concentration of phospholipid P, which in contrast decreases in the cerebellum (CB) during development. Moreover, the data show interesting differences between the right and the left portion of the brain. The distribution of phospholipid P and the fatty acid composition of phospholipids were asymmetric between left and right OL and CH, as were the concentrations of DNA and cholesterol, demonstrating lateralized neurochemical development in these structures, i.e., left OL, right OL, left CH, and right CH. The data are discussed also in relation to the potential importance of neurochemical lateralization for determining lateralized embryonic and postnatal behavior of this species.

Animals↗
PubMed1995

Potential efficacy and toxicity of GM1 ganglioside against trimethyltin-induced brain lesions in rats: comparison with protracted food restriction.

GM1 ganglioside (one week each at 10, 5, and 2.5 mg GM1/kg per day, ip) or gradual food restriction leading to a reduction in body weight to 75% of control were tested for their ability to block or reverse histopathologic and behavioral effects of trimethyltin (TMT) poisoning in rats. TMT (a single oral gavage of 6.0 mg TMT HCI/kg body weight) reduced hippocampal weight, decreased hippocampal cell counts, decreased autoshaped learning measures, and suppressed progressive fixed ratio (PFR) lever pressing without affecting stable lever pressing. Neither GM1 nor greater food restriction affected hippocampal weight. Greater food restriction prevented TMT's effects on autoshaping but not on PFR behavior, was without behavioral effects in animals not treated with TMT, and did not affect hippocampal histology. GM1 prevented certain TMT-induced decrements in autoshaping and PFR behavior but also suppressed autoshaping and stimulated stable fixed ratio behavior in animals not treated with TMT. GM1 also reduced hippocampal serotonin concentration, another "lesion-like" change. GM1 blocked TMT-induced hippocampal CA3b cell loss, but did not protect CA3c cells, the main locus of TMT hippocampal damage. The results support the idea that exogenous GM1 is a potent neuroactive agent with complex actions in intact organisms, potentially beneficial and potentially toxic. Like GM1, food restriction induces complex and potentially beneficial effects, but it lacked GM1's biochemical and behavioral "side effects" (i.e. toxicity) in these experiments.

Animals↗
PubMed1995

Glycosyltransferase activities in human meningiomas. Preliminary results.

The biosynthesis of a given glycosphingolipid is under the control of specific glycosyltransferases, while its catabolism is catalyzed by step-wise action of glycosidases. The net amount of glycolipids apparently result from the difference between these two processes. However, other parameters should be taken into consideration, such as intracellular recycling of catabolic products, membrane insertion, and membrane turnover. In order to establish a possible correlation between ganglioside expression in brain tumor and the activities of the enzymes involved in their metabolism, we analyzed the activities of specific sialyltransferases (SAT-1 and SAT-2), galactosyltransferase (GalT-4), N-acetylgalactosaminyltransferase (GalNAcT-1), and N-acetylglucosaminyltransferase (GlcNAcT-1) in 9 human meningiomas whose ganglioside pattern was characterized either by the predominance ganglioside GM3 (4 out of 9) or ganglioside GD3 (5 out of 9). The results indicated a strong correlation between the GM3/GD3 ratio and SAT-2 activity; to the contrary, SAT-1 activity did not show any correlation if compared with the Lc2/GM3 ratio. In all the samples where GM3 was the main ganglioside, little or no activity of GalNAcT-1 and GlcNAcT-1 was detectable.

Carbohydrate Sequence↗
PubMed1994

Enzyme replacement treatment in type 1 and type 3 Gaucher's disease.

The development of intravenous enzyme-replacement treatment for Gaucher's disease has changed life expectancy in cases without neurological involvement (type 1). The effects in patients with neurological involvement are unknown. We treated 12 Italian patients, types 1 (9) and 3 (3), with intravenous alglucerase: 70-120 IU/kg per month for type 3 and 30-60 IU/kg per month for type 1. Maintenance infusions were biweekly in patients without neurological symptoms, whereas in one symptomatic type 3 patient, infusion was weekly. All patients improved; a resumption of growth in children with growth retardation was observed and spleen and liver reduced in size. In one type 3 patient, a bone callus formed during treatment and enabled the patient to walk. Laboratory tests showed rapid increase of haemoglobin in anaemic patients, and a slower response in patients with thrombocytopaenia. In 4 patients there was temporary hypocalcaemia immediately after the beginning of treatment. Neurological symptoms were present in 1 of the type 3 patients, and electroencephalogram was abnormal in another. After 2 years of treatment, the patient with symptoms showed an improvement of psychomotor skills and of IQ from 50 to 60. Genotype analysis showed a high frequency of the 1448C mutation (54.5%). The 9 patients carrying this allele came from Italian regions which in the past had been invaded from north Europe and Scandinavia. Enzyme replacement in Gaucher's type 1 can also be effective at low doses and even with a 2-week interval between infusions. This makes treatment cheaper, and reduces hospital stay for patients.

Adolescent↗
PubMed1994

Cholesterol, triacylglicerols and phospholipids during Xenopus embryo development.

Cholesterol, triacylglicerol and phospholipid content was analysed in Xenopus embryos during their early development (from day 1 to day 6). Triacylglicerols decrease significantly during the analysed stages and this can be explained by their use as energy substrate. Cholesterol and phospholipids, on the contrary, remain constant and are probably redistributed inside the embryo. The different phospholipid classes were separated by HPTLC. A constant decrease of PC and a marked increase of PS has been observed. The fatty acid composition of the single phospholipid classes has been analysed.

Animals↗
PubMed1994

Altered membrane lipid composition in a human meningosarcoma.

In a sample of meningosarcoma, obtained at the time of surgery, the amount of total gangliosides and phospholipids was examined, together with the cholesterol content and the distribution of different ganglioside and phospholipid species. The phosphatidylinositol, phosphatidylinositol-4-phosphate, phosphatidylinositol-4, 5-bisphosphate and phosphatidylcholine fatty acid composition was also analyzed. The ganglioside pattern in the meningosarcoma was different from the previously reported pattern in meningiomas of different histological origin, showing a higher concentration of GD3, indicating that the so-called b pathway of ganglioside biosynthesis was the preferred one in this type of tumor; moreover the percentage content of polysialylated gangliosides was very low. Cholesterol and phospholipid content was lower than in meningiomas; the phosphatidylcholine increase and the sphingomyelin decrease would indicate a lower membrane microviscosity, a characteristic of tumor cells. Phosphoinositide and phosphatidylcholine fatty acid analysis revealed a considerable amount of docosahexaenoic acid. This abnormal presence of this fatty acid could lead to the production, after receptor stimulation, of a diacylglycerol containing docosahexaenoic acid, which, in turn, could be responsible for an altered activation pattern of protein kinase C, in this way promoting carcinogenesis.

Arachidonic Acid↗
PubMed1994

Mutations and polymorphisms of the gene encoding the beta-subunit of the electron transfer flavoprotein in three patients with glutaric acidemia type II.

Electron transfer flavoprotein (ETF) is a heterodimeric enzyme composed of an alpha-subunit and a beta-subunit and contains a single equivalent of FAD per dimer. ETF deficiency can be demonstrated in individuals affected by a severe metabolic disorder, glutaric acidemia type II (GAII). In this study, we have investigated for the first time the molecular basis of beta-ETF deficiency in three GAII patients: two Japanese brothers, P411 and P412, and a third unrelated patient, P485. Molecular analysis of the beta-ETF gene in P411 and P412 demonstrated that both these patients are compound heterozygotes. One allele is carrying a G to A transition at nucleotide 518, causing a missense mutation at codon 164. This point mutation is maternally derived and is not detected in 42 unrelated controls. The other allele carries a G to C transversion at the first nucleotide of the intron donor site, downstream of an exon that is skipped during the splicing event. The sequence analysis of the beta-ETF coding sequence in P485 showed only a C to T transition at nucleotide 488 that causes a Thr154 to Met substitution and the elimination of a HgaI restriction site. HgaI restriction analysis on 63 unrelated controls' genomic DNA demonstrated that the C488T transition identifies a polymorphic site. Finally, transfection of wild-type beta-ETF cDNA into P411 fibroblasts suggests that wild-type beta-ETF cDNA complements the genetic defect and restores the beta-oxidation flux to normal levels.

Amino Acid Metabolism, Inborn Errors↗
PubMed1992

Treatment of sphingomyelinase deficiency by repeated implantations of amniotic epithelial cells.

Five young patients with Niemann-Pick disease type B were treated with repeated implantations of amniotic epithelial cells, as a source of exogenous sphingomyelinase. This treatment abolished the recurrent infections, mainly of the respiratory tract, and led to other improvements of the general conditions of the patients. In particular, we noticed a disappearance of vomiting, a recovery from muscular hypotrophy, and significantly reduced pulmonary distress. In four subjects, who were in a prepuberal state, there was a puberal spurt with a concomitant burst of growth. In two cases, characterized by a greater than normal content of sphingomyelin in urinary sediments, a single implantation caused a sustained normalization of sphingomyelin and total phospholipids in the urine. Finally, sphingomyelinase activity of peripheral leukocytes, when assayed 0.5 to 4 months after some of the implantations, showed a rise to heterozygous values in 30-40% of the assays.

Adolescent↗
PubMed1992

Different fatty-acid profiles in phosphoinositides from human fibroblastic meningiomas with or without chromosome 22 monosomy.

The fatty-acid composition of phosphoinositides derived from 13 human fibroblastic meningiomas, divided according to the presence or the absence of monosomy of chromosome 22, was analyzed. Phosphoinositides were separated into their 3 main components: phosphatidylinositol, phosphatidylinositol-4-phosphate, and phosphatidylinositol-4,5-bisphosphate. In all the tumors, regardless of cytogenetic differences, remarkable differences were detected between phosphatidylinositol and phosphatidylinositol-4-phosphate or phosphatidylinositol-4,5-bisphosphate. In meningiomas with 22 monosomy, there was a significant decrease in the relative amount of arachidonate in all the phosphoinositide fractions; this situation might determine diminished down-regulation of the corresponding diacylglycerol, derived by the phospholipase-C-stimulated hydrolysis of phosphoinositides, and, consequently, different protein-kinase-C stimulation.

Chromosome Aberrations↗