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S Dahan

Publications and source records attributed to S Dahan.

At least 37 records · Page 2Linked to original sources
PubMed1998

A novel dynamin-like protein associates with cytoplasmic vesicles and tubules of the endoplasmic reticulum in mammalian cells.

Dynamins are 100-kilodalton guanosine triphosphatases that participate in the formation of nascent vesicles during endocytosis. Here, we have tested if novel dynamin-like proteins are expressed in mammalian cells to support vesicle trafficking processes at cytoplasmic sites distinct from the plasma membrane. Immunological and molecular biological methods were used to isolate a cDNA clone encoding an 80-kilodalton novel dynamin-like protein, DLP1, that shares up to 42% homology with other dynamin-related proteins. DLP1 is expressed in all tissues examined and contains two alternatively spliced regions that are differentially expressed in a tissue-specific manner. DLP1 is enriched in subcellular membrane fractions of cytoplasmic vesicles and endoplasmic reticulum. Morphological studies of DLP1 in cultured cells using either a specific antibody or an expressed green fluorescent protein (GFP)- DLP1 fusion protein revealed that DLP1 associates with punctate cytoplasmic vesicles that do not colocalize with conventional dynamin, clathrin, or endocytic ligands. Remarkably, DLP1-positive structures coalign with microtubules and, most strikingly, with endoplasmic reticulum tubules as verified by double labeling with antibodies to calnexin and Rab1 as well as by immunoelectron microscopy. These observations provide the first evidence that a novel dynamin-like protein is expressed in mammalian cells where it associates with a secretory, rather than endocytic membrane compartment.

Alternative Splicing↗
PubMed1998

[Yellow nails].

Explore the source record for details and available documents.

Antineoplastic Agents, Phytogenic↗
PubMed1998

[Long-term results of surgical pharyngectomy (uvulo-palato-pharyngoplasty) versus office CO2 laser (L.A.U.P.) for the treatment of uncomplicated snoring].

Two treatments are habitually proposed for snoring without obstructive sleep apnea syndrome: the surgical pharyngotomy, and the treatment by laser done in the office. Our study analyses retrospectively, by telephone questionnaire, a group of 168 snorers, without obstructive sleep apnea syndrome, treated by pharyngotomy (n = 71) or CO2 laser (n = 97) between 1989 and 1993. Results after a mean follow-up of 5 years, with a minimal of 3 years, show for the two procedures the same efficacity, and an equivalent prevalence of side effects. The rate of satisfaction for the patient and her bed-partner is about 50%, in relation to a degradation of therapeutic effect in the long run. We propose to precisely the results and the indications of the surgery and the laser for treatment of uncomplicated rhonchopathy.

Adult↗
PubMed1994

Concentration of intracellular hepatic apolipoprotein E in Golgi apparatus saccular distensions and endosomes.

The intrahepatic distribution of apolipoprotein E has been assessed by immunogold labeling of cryosections as well as by Western blotting of organelles isolated from liver homogenates. Both techniques supported the prior analytical fractionation studies of Wong (1989) who concluded that intrahepatic apoE was largely endosomal. All endosomal components decorated by gold particles indicative of apoE antigenicity in cryosections appeared filled with lipoprotein-like particles thereby accounting for this prominent morphological feature of isolated liver endosomes. The distribution of gold particles about the hepatic Golgi apparatus revealed a high content of apoE in closely apposed endosomes, ca. 400 nm in diameter, double labeled for apoE and internalized HRP. Remarkably, apoE (but not internalized HRP) was also observed within saccular distensions of all saccules of stacked Golgi cisternae but absent from the flattened saccular components as was also observed for apoB. This contrasted with albumin, the major secretory protein, which was uniformly distributed throughout the hepatic Golgi apparatus. These observations support a growing body of evidence for intra-Golgi sorting of secretory material in hepatic Golgi apparatus. The lack of any immunoreactive apoE or albumin in small 70-90 nm vesicles about the Golgi cisternae suggests limits to current models of vesicle-mediated intra-Golgi transport.

Albumins↗
PubMed1992

Correlated biochemical and radioautographic studies of protein turnover in developing rat incisor enamel following pulse-chase labeling with L-[35S]- and L-[methyl-3H]-methionine.

The movement of proteins into and out of enamel was followed over time using a highly sensitive microprecipitation technique to quantify the amount of TCA-insoluble radioactivity present within small pieces of freeze-dried enamel and cells (enamel organ) dissected from the mandibular incisors of rats injected with L-[35S]-methionine. Conventional image processing techniques were also used to estimate the number of silver grains over enamel and cells in radioautographs of mandibular incisors from rats similarly injected with L-[methyl-3H]-methionine. Data from both techniques indicated that the average half-life for labeled proteins secreted into enamel was about 8.9 days. Typically, radioactive proteins accumulated in increasing amounts for 8 hours after which they were lost slowly up to 4 days and more rapidly thereafter when enamel formed during the secretory stage underwent maturation. The half-life for radioactive proteins in cells was only about 20.7 hours. No significant accumulation of radioactivity could be detected in the TCA-soluble or TCA-insoluble fractions of cells as enamel development proceeded. Results from this study suggest that radioautographs provide an accurate estimate of changes occurring to proteins in enamel and cells except at early time intervals (less than 1 hour) when a high percentage of total radioactivity is present within the TCA-soluble fraction of cells.

Animals↗
PubMed1992

Pathogenesis of carbohydrate-induced hypertriglyceridemia using HepG2 cells as a model system.

This study compares the effects of glucose and fatty acid on hepatic lipid synthesis and apolipoprotein (apo) B secretion. To do so, varying concentrations of either glucose or oleic acid were added to the medium in which HepG2 cells were being incubated. Intracellular triacylglycerol and cholesteryl ester synthesis and secretion were measured by addition of radioisotopic tracers and by determination of mass, whereas apo B concentration in the medium was measured by a specific enzyme-linked immunosorbent assay. The data indicate that increasing concentrations of glucose in the medium resulted in increased synthesis of triacylglycerol within the cell and increased secretion of triacylglycerol into the medium. Apo B secretion into the medium, however, did not change, and intracellular synthesis and secretion of cholesteryl ester did not change as well. By contrast, addition of oleic acid to the medium resulted in increased synthesis and secretion of both cholesteryl ester and triacylglycerol, and this was associated with increased secretion of apo B into the medium. Thus, a carbohydrate load resulted in secretion of normal numbers of triacylglycerol-enriched apo B particles by this hepatocyte cell line, whereas a fatty acid load led to the secretion of increased numbers of apo B particles, which were essentially normal in composition.

Apolipoproteins B↗
PubMed1989

[Iconography of Buschke Ollendorff syndrome: x ray computed tomography and nuclear magnetic resonance of osteopoikilosis].

The authors report a case of Buschke-Ollendorff syndrome in a 66-year old woman who had been admitted for polymyalgia rheumatica. Dermatological examination showed innumerable small ivory papullae bilaterally and symmetrically distributed over the back, the shoulders, the flexor aspect of the elbows, the wrists and the thighs. Biopsy of a papulla displayed hypertrophy of the elastic tissue condensed in the deep dermis. Electron microscopy showed dense collagen bundles together with an absence of microfibillae and of anchoring fibres in the superficial dermis. Standard radiology, computed tomography (CT) and nuclear magnetic resonance (NMR) disclosed small areas of "stippled" bone densification in the lower middle part of the femoral heads, leading to a diagnosis of osteopoikilosis. Buschke-Ollendorff syndrome was described in 1928 as "dermatofibrosis lenticularis disseminata" associated with a bone-condensing disease called "osteopoikilosis". The condition is transmitted as an autosomal dominant trait. Light and electron microscopy of the skin show densification of collagen structures and elastic fibres that are very numerous and of abnormal structure. Osteopoikilosis may present under two different forms, punctate (Albers-Schomberg syndrome) or striated, corresponding anatomically to areas of compact bone. CT and NMR provide detailed information on the location and structure of bone condensation area.

Aged↗
PubMed1984

Coeliac disease in the Rehovot-Ashdod region of Israel: incidence and ethnic distribution.

The data from a large group of children with biopsy proved coeliac disease born in the Rehovot-Ashdod region of Israel and treated in a regional hospital provided us with the basis for the determination of the annual birth cohort incidence of coeliac disease for the period 1968-81. The findings show a minimum birth cohort incidence of 1.71/1000 live births. The highest incidence rate was in children of Asian origin and the lowest in second generation Israel born. The incidence of coeliac disease rose sharply during the study period.

Celiac Disease↗
PubMed1982

[Therapeutic approach to laryngeal nerve paralysis].

The numerous surgical procedures proposed for the treatment of bilateral recurrent laryngeal nerve paralysis, since the operation first described by Rethi, are reviewed. Because of the principle involved and the simplicity of Loboryles operation it is the preferred method, and the technique employed is described in detail. Results have been satisfactory in a series of patients treated by this procedure and its further development is justified.

Humans↗
PubMed1981

[Reconstructive laryngectomy (author's transl)].

The technique, indications, and results of the surgical operation known as reconstructive laryngectomy are described. The intervention involves the performance of a supracricoid subtotal laryngectomy with conservation of an arytenoid, followed by a cricohyoidopexy. This allows re-establishment of the triple function of the aerodigestive junction : phonatory, respiratory, and deglutition; a permanent tracheotomy thus not being necessary. Analysis of results of 103 operations of this type demonstrated that, when conducted under very precise conditions concerning the indications for surgery and the technique employed (conservation of recurrent nerve function of one side), the percentage of permanent tracheotomies following laryngectomy diminished from 72 to 33 p. cent.

Deglutition↗