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Biomedical subjects

D Perrin

Publications and source records attributed to D Perrin.

At least 19 recordsLinked to original sources
PubMed1992

No evidence for calpain I involvement in fodrin rearrangements linked to regulated secretion.

Stimulation of secretion in chromaffin and parotid acinar cells is associated with dramatic rearrangements of the subplasmalemmal cytoskeleton, notably of fodrin and F-actin. It has been proposed that a proteolytic cleavage of fodrin resulting from an activation of the neutral calcium activated protease (calpain) could be responsible for these changes. Using an affinity-purified anti-alpha-fodrin antibody, several cleavage products of fodrin could clearly be detected following incubation of total cell homogenates from chromaffin and parotid acinar cells with purified calpain I. On the other hand, maximum stimulation of secretion of chromaffin cells by nicotine, and of parotid acinar cells by carbachol plus isoproterenol, was not associated with an increased appearance of cleavage products of fodrin. This result is not compatible with the 'proteolytic cleavage' hypothesis.

Adrenal Medulla↗
PubMed1992

Does elective sclerotherapy improve the efficacy of long-term propranolol for prevention of recurrent bleeding in patients with severe cirrhosis? A prospective multicenter, randomized trial.

We conducted a prospective, multicenter, randomized trial to compare the efficacy of sclerotherapy plus propranolol with that of propranolol alone in the prevention of recurrent gastroesophageal bleeding in severely cirrhotic patients. For 2 yr (1987 to 1988) 131 patients (96% of whom were alcoholic) with Child-Pugh class B or C cirrhosis (56% were class B and 44% were class C) were randomly assigned to one of our two treatment groups after cessation of variceal bleeding, without hemostatic sclerosis, and were observed for at least 2 yr. Treatment observance was good in 89% of cases; alcohol withdrawal was observed in 62% of cases. Sclerotherapy was performed weekly with 1% polidocanol, and variceal obliteration was obtained in 83% of cases, in a mean number of four sessions. The cumulative percentages (expressed as mean +/- S.D.) of recurrent bleeding at 2 yr were 42% +/- 6% for propranolol plus sclerotherapy and 59% +/- 6% for propranolol alone (a nonsignificant difference). Twenty-eight patients from the propranolol group but only 12 patients from the propranolol-plus-sclerotherapy group had recurrent bleeding from esophageal variceal rupture (p less than 0.01). The total number of blood units per patient with recurrent bleeding was slightly but not significantly more important in the propranolol group (8 +/- 7) than in the propranolol-plus-sclerotherapy group (5 +/- 5; p = 0.09).(ABSTRACT TRUNCATED AT 250 WORDS)

Esophageal Diseases↗
PubMed1992

cAMP and Ca(2+)-mediated secretion in parotid acinar cells is associated with reversible changes in the organization of the cytoskeleton.

The potential involvement of actin and fodrin (brain spectrin) in secretory events has been assessed in primary cultured guinea pig parotid acinar cells, using as a tool affinity purified anti-alpha-fodrin antibody, phalloidin, and immunofluorescence techniques. In resting parotid acinar cells fodrin and actin appeared as a continuous ring under the plasma membrane of most of the cells. Upon stimulation with secretagogues fodrin and actin labeling at the level of the plasma membrane disappeared almost completely. To establish a correlation between secretion and cytoskeletal changes at the individual cell level, anti-alpha-amylase-antibodies were used to label secreted amylase exposed at the surface of secreting cells. The number of cells expressing alpha-amylase on their surface followed bulk secretion of alpha-amylase. A strict correlation between secretion and alteration of the actin-fodrin labeling was observed at the individual cell level. The cytoskeletal changes occurred in parallel with secretion independently of the secretagogue used (carbamoylcholine in the presence of Ca2+, isoproterenol in presence or absence of Ca2+, forskolin, or dibutyryl-cyclic-AMP). The changes were reversible upon removal of the secretagogue. Since Ca2+, as well as cAMP-mediated secretion, was associated with the same kind of cytoskeletal changes, a reorganization of the cytoskeleton may play an essential part in regulated secretion.

1-Methyl-3-isobutylxanthine↗
PubMed1991

Palindromic units are part of a new bacterial interspersed mosaic element (BIME).

Palindromic Units (PU or REP) were defined as DNA sequences of 40 nucleotides highly repeated on the genome of Escherichia coli and other Enterobacteriaceae. PU are found in clusters of up to six occurrences always localized in extragenic regions. By sorting the DNA sequences of the known PU containing regions into different classes, we show here for the first time that, besides the PU themselves, each PU clusters contains a number of other conserved sequence motifs. Seven such motifs were identified with the present list of PU regions. Remarkably, each PU cluster is exclusively composed of a mosaic combination of PU and of these other sequence motifs. We demonstrate directly by hybridization experiments that one of these motifs (called L) is indeed present at a large number of copies on the Escherichia coli chromosome and that its distribution follows the same species specificity as PU sequences themselves. We propose that the mosaic pattern of motif combination in PU clusters reveals a new type of bacterial genetic element which we propose to call BIME for Bacterial Interspersed Mosaic Element. The Escherichia coli genome contains about 500 BIME.

Base Sequence↗
PubMed1991

[Prevention of recurrent hemorrhage in patients with cirrhosis. Results of a controlled trial of propranolol versus endoscopic sclerotherapy].

Between July 1984 and March 1986, we conducted a prospective randomized trial comparing propranolol and endoscopic sclerotherapy in the prevention of recurrent variceal hemorrhage in a group of non selected alcoholic cirrhotics. Seventy-six patients with variceal hemorrhage were randomized to receive propranolol (P) (34 patients), or sclerotherapy (S) (42 patients) approximately 12 days after initial bleeding. The 2 groups were similar as concern age, sex, etiology of cirrhosis, severity of liver failure, the number of previous hemorrhages, and the severity of initial hemorrhage. No side effects were observed in the P group; 20 patients (48 percent) in the group S had at least one side effect although minor. After an average follow-up of 36 months, 18 patients in group P (53 percent) and 23 in group S (55 percent) had hemorrhagic recurrence. Rebleeding occurred from other sources than esophageal varices in 5 patients, in the group S only. Five patients in group P and 8 patients in group S died of rebleeding. During the follow-up period, 8 patients in group P (23 percent) and 13 patients in group S (31 percent) died. No significant difference could be demonstrated between the 2 groups as regards the percentages of patients without variceal rebleeding or survival, calculated according to the Kaplan Meier method. In conclusion, in this trial, no significant difference could be demonstrated between propranolol and endoscopic sclerosis in the prevention of recurrent variceal hemorrhage in alcoholic cirrhotic patients.

Actuarial Analysis↗
PubMed1991

[Cranio-maxillo-facial fibrous dysplasia].

The fibrous dysplasia of the bones is a big disease, but it has to be considered as an expansive process with local malignancy in the cranio-maxillo-facial localizations. After a review of the literature, 7 cases of fibrous dysplasia are presented. The only curative treatment is surgical, generally mutilating, it has to be completed by a restoring intervention in same time. The abstention and the modeling surgery can be indicated exceptionally, it requires a regular X ray examination, and a clinical follow-up.

Adolescent↗
PubMed1990

DNA polymerase I and a protein complex bind specifically to E. coli palindromic unit highly repetitive DNA: implications for bacterial chromosome organization.

Starting from a crude E. coli extract, two activities which specifically protect highly repetitive bacterial DNA sequences (called PU for Palindromic Unit or REP for Repetitive Extragenic Palindromic sequence) against a digestion with Exonuclease III have been purified. We show that one of these activities is due to the DNA polymerase I (Pol I). This constitutes the first indication for a specific interaction between Pol I and a duplex DNA. This interaction requires the presence of PU. It was confirmed and analyzed by native gel electrophoresis and DNase I footprinting experiments. The other activity contained at least five polypeptides. Its binding to PU DNA sequences was confirmed by native gel electrophoresis. Implications for the possible origin and functions of PU are discussed.

Bacterial Proteins↗
PubMed1990

[Herpes simplex virus in dental practice, longitudinal epidemiologic study].

The percentage of asymptomatic recurrences was measured using systematic salivary samples from 443 patients from January 1987 to April 1988. The study of symptomatic recurrences involved 11 patients having clinical lesions due to herpes simplex buccofacial infections. The analysis revealed 0.89% of the patients encountered (N = 443) had assymptomatic salivary excretion. The study of patients showing clinical signs of herpes simplex revealed that the virus was found in 0.37% of the patients seen in consultation (N = 6,379). The saliva carried the virus in 4 out of 5 cases of oral recurrence and in 12.5% of the cases (N = 32) of extraoral recurrence. The occurrence of the virus during the course of odontological practice exists in clinically detectable forms, but also, and in a non-negligible manner, may be in clinically undetectable forms. These data should be taken into consideration in the daily exercise of the profession by virtue of the risk of contamination--cross-over which may be brought about.

Adolescent↗
PubMed1989

Immunity protein is not required for the bactericidal activity of colicin E3.

Plasmid pLAX3, carrying the colicin E3 gene, was used to direct the in vitro synthesis of a colicin E3* molecule totally devoid of its immunity protein. We established that this molecule is able to kill sensitive Escherichia coli cells in the total absence of immunity protein. Therefore, all of the information required for colicin E3 action is located on the colicin polypeptide itself. Furthermore, our studies indicated that immunity protein protects the C-terminal enzymatic part of native colicin E3 protein against proteolytic degradation before or during its translocation across the cell envelope. These results are discussed in relation to the mode of entry of colicin E3 into bacterial cells.

Bacterial Proteins↗
PubMed1988

Alpha-fodrin (brain spectrin) immunocytochemical localization in rat vestibular hair cells.

The presence of a spectrin-related protein in rat vestibular sensory receptors was demonstrated by immunocytochemistry and immunoblotting using affinity purified anti alpha-fodrin antibodies. Intense immunoreactivity was found in the apical pole of sensory hair cells where it seems to be concentrated in the cuticular plate. In contrast, alpha-fodrin immunoreactivity was absent from the stereocilia. We suggest that a spectrin-related protein participates in the organization of the cuticular plate of vestibular hair cells by cross-linking actin filaments as well as by anchoring the cuticular plate to the apical cell membrane.

Animals↗
PubMed1987

Species specificity of bacterial palindromic units.

We described previously a family of dispersed palindromic sequences highly repeated in Escherichia coli and Salmonella typhimurium genomes. These sequences, called PU (palindromic units), are located outside structural genes. We report here observations suggesting that PU may have a role in bacterial speciation.

Base Sequence↗