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Biomedical subjects

G Bach

Publications and source records attributed to G Bach.

At least 19 recordsLinked to original sources
PubMed1992

Mucolipidosis type IV: accumulation of phospholipids and gangliosides in cultured amniotic cells. A tool for prenatal diagnosis.

Cultured amniotic fluid cells from two mucolipidosis type IV (MLIV)-affected fetuses demonstrated accumulation of phospholipids and gangliosides when compared with normal controls. Like cultured skin fibroblasts from MLIV patients, cultured amniotic cells from the affected fetuses accumulated primarily lyso phospholipids and this could be demonstrated by radioactive labelling with appropriate precursors, either inorganic phosphate or oleic acid. Furthermore, like cultured skin fibroblasts, there was significant retention of exogenously supplied GD1A ganglioside in the affected amniotic cells. This storage was previously demonstrated to be unique to MLIV and thus can be used at present as a specific procedure for prenatal diagnosis of MLIV.

Amniocentesis↗
PubMed1992

Mucolipidosis type IV. Presentation of a mild variant.

The authors report a 16-year-old girl with mucolipidosis type IV. She was referred because of deteriorating vision over the past three years. Corneal clouding with the appearance of cornea verticillata and retinal dystrophy were the main ophthalmological findings. Except for clumsiness no psychomotor retardation was present. Ultrastructural analysis of a conjunctival biopsy and cultured fibroblasts suggested a diagnosis of mucolipidosis type IV which was confirmed by biochemical studies. This patient represents the mildest described presentation of mucolipidosis type IV.

Adolescent↗
PubMed1991

Hunter syndrome in Jews in Israel: further evidence for prenatal selection favoring the Hunter allele.

Among all the Jewish families with Hunter patients in Israel, 10 were Ashkenazi or Moroccan in origin. In those families, there was a paucity of new mutations. In addition, a significant deviation of the segregation ratio between the Hunter gene and the normal allele was demonstrated among the offspring of heterozygous mothers or siblings of affected children in these families. These results confirm and extend our previous observations suggesting selection in favor of the X chromosome carrying the Hunter allele among Ashkenazi and Moroccan Jews.

Alleles↗
PubMed1991

Ontogenetic changes in hepatic glutathione system (synthesis, catabolism, export) of male Uje:WIST rats.

The age-courses of concentrations of reduced (GSH) and oxidized (GSSG) glutathione, of GSH synthesizing enzyme activities, of glutathione S-transferase (GST), of GSSG-reductase (GR) and of biliary GSH and GSSG export were measured in livers from male Uje:WIST rats. Additionally, the age-courses of plasma GSH and GSSG concentrations were investigated. The hepatic level of GSH showed a biphasic pattern with a first maximum immediately after birth and a small second peak at the 50th day of life. The GSSG level increased continuously up to day 60 of life. The cytosolic GSH synthesizing enzyme activities showed diverse developmental patterns indicating different regulation principles. The hepatic activity of GR was relatively constant in the different age groups after birth. The GST activity (with o-dinitrobenzene as substrate) was relatively low at birth (about 30% of the maximum measured at day 60 of life). The maximum of GSH plasma level was found at birth. With increasing age a significant decrease in this level was observed. The excretion rate of total GSH (GSH + 2 GSSG) in bile was found to increase about 9-fold between 15 and 105 days of age. The results indicate that changes of hepatic GSH concentration with age are dependent on numerous factors. The balance between synthesis, catabolism and export is important for the maintenance of this level.

Aging↗
PubMed1991

Krabbe disease in Israel.

Over a period of 15 years, 18 infants affected with Krabbe disease were diagnosed in Israel. None of the patients were Jews. Six were Druze from a large kindred in which a very high incidence of the disease was previously reported. The 12 other patients were Moslem Arabs; 7 were from two adjacent villages and most of them were found to be related, originating from a large kindred in which the incidence of the disease is 1/130 live births. Three other patients were from a third large kindred that also had a high incidence of Krabbe disease. Israel's population includes communities in which a high incidence of lysosomal diseases has been found. The incidence of these diseases in Israel may be reduced by delineating the populations at risk. With respect to Krabbe disease, as reported here, the tests for heterozygote detection are not sufficiently accurate for a screening of the populations at risk. Prevention is possible only by prenatal diagnosis in the families at risk.

Female↗
PubMed1989

The identification of lysosomal ganglioside sialidase in human cells.

In this report we present evidence for the existence of a lysosomal ganglioside sialidase. The sialidase activity was solubilized by sonication and stimulated by cholate. The absence of ganglioside sialidase activity in sialidosis patients indicates that lysosomal sialidase is active towards gangliosides and glycoproteins. The plasma membranes were associated with two types of ganglioside sialidase activities, one was enhanced by cholate while the other was partially inhibited by this detergent.

Cell Fractionation↗
PubMed1989

Phosphatidylcholine storage in mucolipidosis IV.

The accumulation of phosphatidylcholine (PC) in cultured fibroblasts of mucolipidosis IV (MLIV) patients was studied by subcellular fractionation on percoll gradients. Labelled PC accumulated in secondary lysosomes of the MLIV cells in significantly higher rates when compared to normal controls incubated with the precursors [32P]phosphate or [14C]choline. This accumulation was noted after 4 days of pulse and became more profound after 7 days of chase resulting in a 30-fold increase of this substance in the lysosomal fraction of MLIV compared to normal controls. On the other hand, no significant increase of radioactive PC was demonstrated in the buoyant fraction of the affected cells, and similarly the rate of disappearance of labeled PC from this fraction was identical in MLIV and controls. The retention of PC in lysosomes of MLIV could also be demonstrated following incubation of cultured fibroblasts with the radioactive phospholipid itself. In these experiments increased labelled PC in MLIV was also noted in endosomes, which are involved in the uptake process of PC enroute to the lysosomes. The metabolic defect leading to this storage in MLIV has not yet been identified, but these data indicate impairment in the lysosomal catabolism of phospholipids in MLIV.

Cells, Cultured↗
PubMed1989

Ganglioside GM3 sialidase activity in fibroblasts of normal individuals and of patients with sialidosis and mucolipidosis IV. Subcellular distribution and and some properties.

Sensitive assays for the determination of the ganglioside sialidase activity of fibroblast homogenates were established using ganglioside GM3, 3H-labelled in the sphingosine moiety, as a substrate. Ganglioside GM3 sialidase activity was greatly stimulated by the presence of the non-ionic detergent Triton X-100 and was further enhanced by salts such as NaCl; the optimal pH was 4.5. The subcellular localization of this activity was determined by fractionation using free-flow electrophoresis and found to be exclusively associated with the marker for the plasma membrane, but not with that for lysosomes. This Triton-stimulated ganglioside sialidase activity was selectively inhibited by preincubating intact cells in the presence of millimolar concentrations of Cu2+, suggesting that the activity resides on the external surface of the plasma membrane. In normal fibroblasts homogenates, ganglioside GM3 sialidase was also greatly stimulated by sodium cholate. In contrast to the Triton X-100-activated reaction, however, it was not diminished by prior incubation of intact cells in the presence of Cu2+. Only after cell lysis was Cu2+ inhibitory. the cholate-stimulated ganglioside sialidase activity thus paralleled the behaviour of the lysosomal 4-methylumbelliferyl-alpha-D-N-acetylneuraminic acid (4-MU-NeuAc) sialidase. In fibroblasts from sialidosis patients, the cholate-stimulated ganglioside GM3 sialidase activity, but not that of the Triton-activated enzyme, was profoundly diminished. In fibroblasts from patients with mucolipidosis IV (ML IV), both the Triton X-100- and the cholate-stimulated ganglioside GM3 sialidase activities were in the range of normal controls. The Triton-activated enzyme was associated with the plasma membrane in the same manner as in normal cells. Our findings suggest that, in human fibroblasts, there exist two sialidases that degrade ganglioside GM3: one on the external surface of the plasma membrane, and another that is localized in lysosomes and seems identical with the activity that acts on sialyloligosaccharides and 4-MU-NeuAc. As neither activity was found to be deficient in ML IV fibroblasts, our results argue against the hypothesis of a primary involvement of a ganglioside GM3 sialidase in the pathogenesis of ML IV.

Cell Membrane↗
PubMed1989

Gaucher disease type I and pregnancy.

We surveyed 47 pregnancies of 17 women affected with Gaucher disease (GD) type I. In two women affected with the severe form of GD type I, no change was observed in the course of the disease during pregnancy. In one patient with the moderate form of the disease there was an exacerbation of the disease during and after pregnancy, and thereafter two subsequent pregnancies of this woman ended by early spontaneous abortion. Four women were diagnosed during their pregnancy or soon after delivery suggesting in these women an exacerbation related to pregnancy. In the other ten women there was no change in the course of the disease. In general, the pregnancies of women affected with GD were normal; however, six women needed blood transfusion during pregnancy or at delivery. From these data it is suggested that there is some risk to pregnant women affected with GD type I, and accordingly, appropriate follow-up should be planned at the beginning of pregnancy in these patients.

Delivery, Obstetric↗
PubMed1988

The distinction between arylsulphatases in chorionic villi.

The relatively high activity of arylsulphatase C (ASC) in the placenta is a potential risk for the misdiagnosis of arylsulphatase A (ASA) or arylsulphatase B (ASB) deficiency in chorionic villus sampling when assayed by synthetic substrates. A clear distinction between these enzymes can be achieved in either the direct villi or the cultured villi cells. Interestingly, the activity of ASC differed significantly in cultured villi cells when prepared by two different methods, namely, minced villi versus treatment with trypsin and collagenase, while ASA and ASB were not affected by these treatments. Whether ASC was directly affected by one of these treatments or whether a selection of cells with different ASC levels was achieved is not yet clear, but this phenomenon clearly indicates the importance of precise definition of CVS preparations to correlate with the enzyme activity data.

Arylsulfatases↗
PubMed1988

Phospholipids accumulation in mucolipidosis IV cultured fibroblasts.

Cultured fibroblasts from mucolipidosis IV patients accumulated phospholipids when compared to normal controls or cells from other genotypes. The major stored compounds were identified as phosphatidylcholine, phosphatidylethanolamine and to a larger extent lysophosphatidylcholine and lysobisphosphatidic acid. Pulse chase experiments of 32P-labelled phospholipids showed increased retention of these compounds in the mucolipidosis IV lines throughout the pulse and chase periods. Phospholipase A1, A2, C, D and lysophospholipase showed normal activity in the mucolipidosis IV lines and thus the metabolic cause for this storage remains to be identified.

Cells, Cultured↗
PubMed1988

Culture conditions found to minimize false positive diagnosis of lysosomal storage disorders.

The effect of culture conditions on the ultrastructure and enzyme activities of cultured skin fibroblast cells relevant to the diagnosis of lysosomal storage disorders are reported. The parameters examined were: pH of the culture media, type of media, increasing cell passage, and day of harvest. Ultrastructural changes were defined in terms of the number of lysosome-like inclusion bodies per cell according to a method devised in our laboratory and proven reliable in the detection of affected individuals. Our biochemical results included determination of enzyme activities of beta-hexosaminidase, alpha-mannosidase, beta-glucuronidase-lysosomal enzymes, arylsulfatase C, a microsomal marker, and 5' nucleotidase, a plasma membrane marker. Our results indicate that the cellular ultrastructure is more sensitive than enzyme activity to changes in culture conditions. The resulting ultrastructural "artifacts" observed under certain conditions were severe enough to result in a mistaken diagnosis. Due to certain difficulties we had previously encountered in heterozygote cultures (for lysosomal storage disorders) of amniotic cells, we decided to examine heterozygote cultures of skin fibroblasts. From these (preliminary) studies it seems that an elevation in the pH over the physiologic levels in the culture media may help to define between normal individuals and affected heterozygotes. On the basis of our results, we recommend that to minimize false positive ultrastructural results for the diagnosis of lysosomal storage disorders, cultures be grown in minimal essential medium, the pH of the medium carefully monitored to remain below 7.4, examining the cultures not later than cell Passage 8 and no later than Day 10 after subculture.

Adult↗
PubMed1988

Histoautoradiographic detection of 3H-thymidine and 3H-proline in the vascular wall of domestic swine in experimental atherosclerosis. Is there an effect of saturated/unsaturated fatty acids in high cholesterol diet?

In vitro labeling of arterial wall samples from domestic swine with tritiated thymidine or proline was used to establish the effect of unsaturated (sunflower oil) or saturated (beef tallow) fatty acids in the presence of enteral cholesterol on DNA and collagen synthesis. Histoautoradiography of samples incubated in vitro gives labeling patterns and indices comparable to in vivo labeling. Preliminary results show that these nutrient fats do not differ in their effect on the DNA and collagen synthesis of vascular wall cells both in the presence and absence of intimal changes.

Animals↗
PubMed1988

Lysosomal accumulation of phospholipids in mucolipidosis IV cultured fibroblasts.

Pulse-chase studies were performed to investigate the metabolism of phosphatidylethanolamine (PEA) in cultured fibroblasts from patients with mucolipidosis type IV (MLIV) and normal controls. When cultured cells were incubated with 3H-ethanolamine, 80-90% of the intracellular radioactivity was associated with PEA. Compared to the metabolism of 3H-PEA in normal cells, the phospholipid was retained in greater amounts and degraded more slowly in the MLIV fibroblasts. The 3H-PEA concentration in lysosomal preparations isolated by Percoll gradients was more than 3-fold greater in MLIV than in normal cells after 10 days chase. These studies indicate that PEA catabolism is deranged in MLIV and suggest that the primary metabolic defect causes abnormal phospholipid catabolism in the lysosomes of affected individuals.

Cells, Cultured↗