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Biomedical subjects

C Meyer

Publications and source records attributed to C Meyer.

At least 325 records · Page 18Linked to original sources
PubMed1994

Recombinant expression of the fdxD gene of Rhodobacter capsulatus and characterization of its product, a [2Fe-2S] ferredoxin.

A gene called fdxD that could potentially code for a ferredoxin has recently been identified upstream of the nitrogenase structural genes in Rhodobacter capsulatus [Willison, Pierrard and Hübner (1993) Gene 133, 39-46]. In the present study, the fdxD gene product has been overproduced in Escherichia coli in a soluble form. The recombinant protein, pink in colour, was purified to homogeneity, and biochemically characterized as a new ferredoxin. It represents the fifth ferredoxin so far identified in R. capsulatus and was designated FdV. Its N-terminal sequence is identical with that of the native ferredoxin isolated from R. capsulatus. U.v-visible-absorption spectra as well as results of c.d. and e.p.r. spectroscopy demonstrated that the fdxD product contained a [2Fe-2S] cluster correctly assembled and incorporated into the polypeptide. Although similar to plant-type ferredoxins, FdV appeared poorly competent in the photo-reduction of NADP+. On the basis of in vitro assays, FdV cannot serve as an electron donor for nitrogenase. The lack of reactivity of FdV in either of these assays may primarily be due to its relatively high mid-point redox potential (E'o = -220 mV, pH 7.5).

Amino Acid Sequence↗
PubMed1994

[Complicated colonic diverticulosis. Changes in treatment and results over 22 years].

OBJECTIVES: The aim of this study was to analyse the clinical course, surgical strategy and results in patients with complicated colonic diverticular disease. METHODS: We retrospectively compared two groups of patients who underwent surgery for complicated colonic diverticulosis from 1970 to 1984 (Group A, n = 94, mean age 60 years, 49 males, 45 females) and from 1985 to 1992 (Group B, n = 76, mean age 63.5, 32 males, 44 females). RESULTS: Patients in the two groups were comparable; only the rate of peritonitis (20 vs 8%) was different (p < 0.05). The most frequent operations in Group A were colostomy-drainage (43%) and Hartman's procedure (26%) in emergency situations and resection with immediate anastomosis (63%) or resection-anastomosis with diverting stomy (19%) in elective cases. In Group B, surgical strategy led to a different pattern of operations, 4 and 56% in emergency, and 94 and 2% in elective surgery, respectively. Overall mortality was 11%, with 17% and 4% in Groups A and B respectively (p < 0.01). This major drop in mortality was particularly important in emergency cases (31 vs 4%; p < 0.02). Morbidity in emergency surgery fell from 21 to 4% (P < 0.0006). Interrupting the use of colostomy-drainage was a major factor in reducing mortality followed by a sharp fall in mortality after Hartmann's procedure (28.5 vs 0%). CONCLUSION: The marked improvement in results between the two groups was mainly due to preferring resections of pathological colonic segments over colostomy-drainage.

Abscess↗
PubMed1994

Isolation and molecular characterization of dTnp1, a mobile and defective transposable element of Nicotiana plumbaginifolia.

By Northern blot analysis of nitrate reductase-deficient mutants of Nicotiana plumbaginifolia, we identified a mutant (mutant D65), obtained after gamma-ray irradiation of protoplasts, which contained an insertion sequence in the nitrate reductase (NR) mRNA. This insertion sequence was localized by polymerase chain reaction (PCR) in the first exon of NR and was also shown to be present in the NR gene. The mutant gene contained a 565 bp insertion sequence that exhibits the sequence characteristics of a transposable element, which was thus named dTnp1. The dTnp1 element has 14 bp terminal inverted repeats and is flanked by an 8-bp target site duplication generated upon transposition. These inverted repeats have significant sequence homology with those of other transposable elements. Judging by its size and the absence of a long open reading frame, dTnp1 appears to represent a defective, although mobile, transposable element. The octamer motif TTTAGGCC was found several times in direct orientation near the 5' and 3' ends of dTnp1 together with a perfect palindrome located after the 5' inverted repeat. Southern blot analysis using an internal probe of dTnp1 suggested that this element occurs as a single copy in the genome of N. plumbaginifolia. It is also present in N. tabacum, but absent in tomato or petunia. The dTnp1 element is therefore of potential use for gene tagging in Nicotiana species.

Amino Acid Sequence↗
PubMed1994

Localization of neuropeptide Y and its C-terminal flanking peptide in human renal tissue.

We produced and characterized three anti-C-flanking peptides of neuropeptide Y (CPON) monoclonal antibodies. The Ka for these antibodies ranged from 0.4 to 0.8 x 10(8) l/mol with an IC50 for CPON(1-30) at about 20 nM as determined by ELISA. All these antibodies are IgG1 and recognize the 16-30 part of CPON. These antibodies and a specific anti-NPY monoclonal antibody were used to study the localization of CPON and NPY in the human kidney. The avidin-biotin technique was employed. NPY and CPON immunoreactivities were present in large amount in the renal tubules of the human kidney but not in the glomeruli. No labeling was found within the renal arterioles and veins, but some immunoreactivity was evidenced in the perivascular area. Because no specific receptor for CPON has been described to date, the presence of this peptide in the tubules may be due to a tubular reabsorption or perhaps to a local synthesis of pro-NPY.

Adrenal Gland Neoplasms↗
PubMed1994

Influence of biperiden and bornaprine on sleep in healthy subjects.

Biperiden, 4 mg, an anticholinergic drug that is relatively selective for the M1 receptor subtype, and bornaprine, 4 mg, a nonselective M1 and M2 antagonist, were administered orally in a randomized, double-blind design to twelve healthy volunteers to investigate the effect on polysomnographically recorded sleep. Both drugs suppressed rapid eye movement (REM) sleep as reflected by an increase of REM latency and a decrease in the percentage of REM sleep period time with the effects of biperiden being more pronounced. No significant effect on slow wave sleep was observed. The results of this study support the hypothesis that both the M1 and the M2 receptor subtype are involved in the regulation of REM sleep in humans.

Adult↗
PubMed1994

Efficacy and tolerability of amitriptylinoxide in the treatment of chronic tension-type headache: a multi-centre controlled study.

Amitriptyline is the medication of first choice in the treatment of chronic tension-type headache. In 197 patients with chronic tension-type headache (87M and 110F with a mean age of 38 +/- 13 (18-68)) efficacy and tolerability of 60-90 mg amitriptylinoxide (AO) were compared with 50-75 mg amitriptyline (AM) and placebo (PL) in a double-blind, parallel-group trial consisting of a four weeks' baseline phase and 12 weeks of treatment. The primary study endpoint was a reduction of at least 50% of the product of headache duration and frequency and a reduction of at least 50% in headache intensity. Statistics used were Fisher's exact test and analysis of variance. No significant difference emerged between AO, AM and PL with respect to the primary study endpoint. Treatment response occurred in 30.3% of the AO, 22.4% of the AM and 21.9% of the PL group. A reduction in headache duration and frequency of at least 50% was found in 39.4% on AO, in 25.4% on AM and in 26.6% on PL (PAO-PL = .1384, PAM-PL = 1.000, PAO-AM = .0973). A reduction in headache intensity of at least 50% was found in 31.8% on AO, in 26.9% on AM and in 26.6% on PL (PAO-PL = .5657, PAM-PL = 1.000, PAO-AM = .5715). Trend analysis with respect to a significant reduction of headache intensity (p < 0.05) and the product of headache duration and frequency revealed a superior effect of AO.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

[Coverage of post-traumatic complex substance loss on the leg. Apropos of a series of 35 cases].

Thirty-five patients with complex post-traumatic leg defects were treated surgically between 1986 and 1992. 10 of these patients had severe open fractures (Gustillo III a, b and c), 25 others suffered from cutaneous and bony sequelae. The choice of the various covering flaps is discussed according to the place and type of defect and also according to their trophic properties. In the light of their own experience and a review of the recent literature, the authors stress the necessity of covering the defect as soon as possible, particularly when a free flap is indicated. Muscle flaps are preferred. Bony reconstruction can then be achieved by a conventional graft.

Adult↗
PubMed1994

[Pancreaticojejunal anastomosis by intussusception of an isolated loop in pancreaticoduodenectomy].

The most frequent and severe complication of pancreaticoduodenectomy is pancreatic fistula due to dehiscence of the pancreas anastomosis. The technique that uses a separate Roux en Y loop for pancreas anastomosis, to reduce the fatal risks of pancreatic fistula, has been described for more than 50 years. With the development of pancreaticogastrostomy, it seems interesting to present a procedure using an isolated loop for the pancreas; this technique, derived from those previously described allows a good intussusception of the pancreatic stump into the intestinal loop. This method was performed in 22 pancreaticoduodenectomies. There were 2 operative deaths unrelated to the pancreaticojejunal anastomosis and one pancreatic fistula, which healed under medical treatment.

Adult↗
PubMed1994

Novel membrane receptors for aldosterone in human lymphocytes: a 50 kDa protein on SDS-PAGE.

Fast in vitro effects of aldosterone on the Na+/H(+)-exchanger, inositoltrisphosphate generation and corresponding specific binding to plasma membranes at Kd-values of approximately 0.1 nM have been found in human mononuclear leukocytes and vascular smooth muscle cells. The novel aldosterone membrane receptor was analyzed on SDS-PAGE after labeling of microsomal membranes from human mononuclear leukocytes with a [125I]-aldosterone-derivative by use of BASED as a photoactivatable crosslinker. Binding of 1 nM [125I]-aldosterone was found at a molecular weight of approximately 50 kDa which was absent with 1 microM cold aldosterone, but not cortisol in the binding media. This aldosterone-selectivity is typical and discriminatory for the new aldosterone membrane receptor. Solubilization of the receptor protein from membranes by high salt concentrations (1 M NaCl, 1 mM EDTA) was not achieved. It, thus, appears as an integral membrane protein. Dithiothreitol, a sulfhydryl agent, does not reduce specific aldosterone binding indicating the absence of SH-groups in the binding domain or sensitive structures of the receptors. The results are the first to characterize the novel membrane receptor for aldosterone with regard to molecular weight and basic properties. These findings and other related results are reviewed here.

Aldosterone↗
PubMed1994

[The covering of radionecrosis in plastic surgery. Apropos of a series of 20 cases].

Twenty radionecroses with various locations were operated on between 1982 and 1993 in the Plastic Surgery Department at Strasbourg. Flap covers were performed. The results and indications as a function of localization and of the size and quality of the structures involved was analyzed for these radio-induced lesions. A wide range of therapeutic option are available to the plastic surgeon who must chose the most reliable reconstruction technique after the most extensive exeresis possible. Muscle and pediculated musculo-cutaneous flaps are preferred due to their safety, their vascular, trophic and anti-infectious quality and their excellent capacity of coverage.

Adult↗
PubMed1994

[Treatment of lithiasis of the common bile duct by endoscopic sphincterotomy and laparoscopic cholecystectomy].

This paper evaluates the treatment of common bile duct stones by endoscopic sphincterotomy (SE) and laparoscopic cholecystectomy (CL). 733 patients presenting with symptomatic cholelithiasis were operated on between March 1990 April 1993; 131 (18%) of them had a preoperative suspicion of common bile duct stones (LVBP): jaundice for 41, biliary acute pancreatitis for 27 and altered liver function tests for 63. 131 retrograde cholangiographies (CPRE) were attempted with an associated SE (113 cases) in the presence of LVBP, biliary pancreatitis, enlargement of common bile duct and appearance of forced papilla. CL was performed 24 to 48 hours later. CPRE +/- SE had no mortality; 1 patient presented a retroduodenal perforation of CBD, requiring surgery. 58 cases (44.2%) of LVBP were diagnosed, without a statistically significant difference according to the clinical pattern. In the group with altered liver function tests only alkaline phosphatase was significantly predictive of LVBP. There was no mortality or morbidity related to CL; conversion rate was 9.8%; 4 of 12 cases of conversion were related to persistence of stones in the common bile duct, without any possibility of laparoscopic extraction. Mean hospital stay was 7.4 days. Efficacy of this sequential method of treatment of LVBP was 91.3%: this method seems satisfactory, not dangerous and minimally invasive, and should be indicated for pre-operative suspected common bile duct stones.

Adolescent↗
PubMed1993

Purification and characterization of a novel dimeric ferredoxin (FdIII) from Rhodobacter capsulatus.

A new ferredoxin, called FdIII, has been isolated and purified from the photosynthetic bacterium Rhodobacter capsulatus. Its complete amino acid sequence has been determined. The FdIII polypeptide consists of 100 residues, including 9 cysteines and has a calculated molecular mass of 10,688 Da, which was confirmed by electrospray mass spectrometry. In its native form, FdIII is a homodimer as deduced from molecular sieve chromatography and non-denaturing polyacrylamide gel electrophoresis, as well as cross-linking experiments. The dimeric ferredoxin was found to contain 15.2 +/- 0.6 iron atoms and 13 +/- 1 inorganic sulfur atoms, consistent with the presence of four [4Fe-4S] clusters/molecule. The UV visible absorption spectrum of oxidized FdIII exhibited maxima at 282 and at 386 nm and a shoulder near 314 nm. FdIII was fully reduced by excess dithionite at pH 8.0 or photochemically using 5-deazaflavin. Anaerobic oxidative titration of reduced FdIII with thionin indicated that each FdIII monomer exchanges two electrons. Exposure of FdIII to air resulted in a rapid and irreversible oxidative denaturation of the Fe-S clusters. The EPR spectrum of fully reduced FdIII showed a broad signal with an average g value of 1.94 that integrated to about two spins/monomer. EPR analysis of partially reduced FdIII (approximately 20% reduction) revealed a complex set of signals which was interpreted as being the resulting sum of the contribution of two distinct paramagnetic centres. Based on its biochemical and spectroscopic properties, it is concluded that FdIII is a dimeric ferredoxin containing four [4Fe-4S] clusters. The synthesis of FdIII occurs only under growth conditions allowing the derepression of nif genes. Results of in vitro electron transfer assays indicate that FdIII cannot serve as an electron donor to nitrogenase.

Amino Acid Sequence↗