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C Meyer

Publications and source records attributed to C Meyer.

At least 343 records · Page 19Linked to original sources
PubMed1993

Expression of the potato tuber ADP-glucose pyrophosphorylase in Escherichia coli.

cDNA clones encoding the putative mature forms of the large and small subunits of the potato tuber ADP-glucose pyrophosphorylase have been expressed separately and together in an Escherichia coli B mutant deficient in ADP-glucose pyrophosphorylase activity. Expression of both subunits from compatible vectors resulted in restoration of ADP-glucose pyrophosphorylase activity. Maximal enzyme activity required both subunits. The expressed ADP-glucose pyrophosphorylase was purified and characterized. The recombinant enzyme exhibited catalytic and allosteric kinetic properties very similar to the enzyme purified from potato tuber. The expressed enzyme activity was neutralized by incubation with antibodies raised against potato tuber and spinach leaf ADP-glucose pyrophosphorylases but not with anti-Escherichia coli enzyme serum. 3-Phosphoglycerate was the most efficient activator and its effect was increased by dithiothreitol. In the ADP-glucose synthesis direction, 3-phosphoglycerate activated the recombinant enzyme nearly 100-fold in the presence of dithiothreitol, with an A0.5 value of 57 microM. The recombinant ADP-glucose pyrophosphorylase was less sensitive to P(i) inhibition and more sensitive to heat denaturation than the potato tuber enzyme. Results suggest that bacterial expression of potato tuber cDNAs could be used to study the role and interaction of the subunits of the native ADP-glucose pyrophosphorylase.

Allosteric Regulation↗
PubMed1993

Comparison of survival curves of gastric cancer patients after surgery according to the UICC stage classification and the General Rules for Gastric Cancer Study by the Japanese Research Society for gastric cancer.

OBJECTIVE: This study compared the UICC classification with the General Rules for Gastric Cancer Study (GRGCS) of the Japanese Research Society by analyzing recent results of gastric cancer surgery in Japan. SUMMARY BACKGROUND DATA: The present UICC stage classification for gastric cancer was published in 1987 and the Japanese GRGCS were published in 1985. Both are based on the results of surveys conducted in the early 1970s. METHODS: The survival curves of 926 patients, who underwent gastric cancer surgery between 1982 and 1985 at Kyoto University Hospital and its 31 associated hospitals, were analyzed according to the UICC classification and the GRGCS using SAS computer software. RESULTS: There was no difference in survival rate between UICC stages IA and IB. GRGCS stage III was found to include UICC stages II, IIIA, and IIIB, and GRGCS stage IV included UICC stages IIIA, IIIB, and IV, with significantly different survival rates. In contrast, each UICC stage included different GRGCS stages with no significant differences in survival rates. The survival rate of stage IV patients of both classifications who underwent gastrectomy was significantly higher than that of stage IV patients receiving bypass or exploratory surgeries. CONCLUSIONS: The UICC classification is better than the GRGCS for classifying gastric cancer in Japan. However, UICC stage I does not need to be subdivided into stages IA and IB, and stage IV should be further subdivided into stages IVA and IVB according to the surgery performed: IVA, gastrectomy, and IVB, bypass or exploratory surgery.

Humans↗
PubMed1993

Mechanism of ischemia-enhanced aminoglycoside binding and uptake by proximal tubule cells.

Preceding ischemia or concurrent hypotension is known to enhance aminoglycoside nephrotoxicity; however, the underlying mechanisms responsible have not been determined. To investigate the effect of preceding mild ischemia on cellular gentamicin handling, brush-border membrane vesicle binding and in vivo cellular gentamicin uptake were quantified using [3H]gentamicin as a tracer. Fifteen minutes of ischemia resulted in a marked increase in apical membrane gentamicin binding (2.8 +/- 0.4 vs. 4.9 +/- 0.8 nmol/mg protein, P < 0.01). This increase was associated with an increased number of binding sites (3.7 +/- 0.3 vs. 9.1 +/- 2.3 nmol/mg protein, P < 0.01) and a reduced binding affinity (11.8 +/- 2.2 vs. 27.7 +/- 10.4 microM, P < 0.01). This increase in gentamicin binding was accompanied by alterations in apical membrane phospholipids including a doubling of phosphatidylinositol (PI) levels (13.8 +/- 0.4 vs. 27.5 +/- 3.1 nmol/mg protein, P < 0.01). Furthermore, treatment of apical membrane vesicles with PI-specific phospholipase C markedly reduced the difference in gentamicin binding between paired control and ischemic membrane fractions. Increased gentamicin binding was associated with increased in vivo uptake of gentamicin by S1/S2 and S3 cells. Outer cortical uptake of gentamicin increased from 2.18 +/- 0.39 to 2.68 +/- 0.27 nmol/mg protein (P < 0.01) after 15 min of ischemia and 4 h of reperfusion. Juxtamedullary uptake also increased from 1.39 +/- 0.31 to 1.75 +/- 0.12 nmol/mg protein (P < 0.01). Immunocytochemical techniques, utilizing immunogold labeling, showed gentamicin was taken up via the receptor-mediated endocytic pathway by S1/S2 and S3 cells. After ischemic injury gentamicin was localized in abnormal intracellular accumulations in S3 but not S1 or S2 cells. Taken together, these data indicate ischemia results in a marked increase in apical gentamicin binding due to increases in apical PI content. This is associated with increased internalization by S1/S2 and S3 cells and abnormal intracellular compartmentalization of gentamicin within S3 cells.

Aminoglycosides↗
PubMed1993

[Seminal fluid, bacteria, and spermatozoa ].

The antibacterial function of the seminal plasma is subdivided in: inhibition of the bacterial proliferation; inhibition of the bacterial adherence; reduction of the concentration of coiled tail spermatozoas. The reduction of the antibacterial activity of the seminal plasma can explain the high frequency of the genital tract reinfection.

Bacteria↗
PubMed1993

[1000 cases of cholecystectomy: 500 by laparotomy versus 500 by laparoscopy].

The authors report 1,000 cases of cholecystectomy for cholelithiasis, excluding all cases with associated common bile duct surgery. The aim of the study was to compare two groups of cholecystectomies, one of 500 laparotomic procedures, evaluated retrospectively, and one of 500 laparoscopic ones, evaluated prospectively. Sex ratio was the same in both groups, and mean age was higher in the second group (54 vs 60) (p < 0.05): acute cholecystitis ratio was similar in both groups (23% vs 19%; NS). During the laparoscopic period, 84 laparotomic interventions were performed (17%), with a 0% mortality and a 18% morbidity rate. Mean operating time was 69' in the first group vs 91' in the second one, with a mean hospital stay of 11 vs 4.5 days (p < 0.001). Mortality rate was 1% vs 0% (p < 0.03) for laparotomic and laparoscopic procedures, and morbidity rate was respectively 11% and 1% (p < 0.001). Conversion rate in laparoscopic surgery was 7%. Two cases (0.4%) in laparoscopic group had a common bile duct lesion diagnosed intraoperatively and 1 case (0.2%) had a residual stone in common bile duct. Laparoscopic surgery is at present the standard technique for the treatment of cholelithiasis and laparotomic cholecystectomy seems only indicated when laparoscopic procedure is contraindicated or impossible.

Adolescent↗
PubMed1993

[Reconstruction of the upper jaw. Apropos of 3 cases].

In this article, we review our personal experience in 3 patients who underwent a maxillectomy for tumor and we discuss the different reconstructive techniques available. We believe that distant pediculed flaps and free flaps give the best result for the functional and cosmetic point of view.

Aged↗
PubMed1993

[Effectiveness and tolerance of amitriptyline oxide in chronic tension headache--a multicenter double-blind study versus amitriptyline versus placebo].

Tricyclic antidepressants, especially amitriptyline, are the medication of first choice in the treatment of chronic tension headache. Few previous studies meet modern standards of study design and statistical analysis. Tolerability and efficacy of 60-90 mg amitriptyline oxide (AO) as a single dose in the evening were compared with 50-75 mg amitriptyline (AM) and placebo (PL) in a double-blind, parallel-group trial consisting of a 4-week baseline phase and 12 weeks of treatment. The 3-armed study was conducted in 7 centers. The inclusion criterion was tension-type headache on at least 15 days monthly with a duration of at least 6 months. Exclusion criteria were a migraine history, previous participation in another clinical trial within the last 3 months, drug abuse, medication with other antidepressants or tranquilizers, current use of other acknowledged prophylactic headache medication, lack of compliance, major psychiatric disorder according to DSM-III and medical contra-indications against tricyclic antidepressants. The primary study endpoint was a reduction at least 50% of the product of headache duration and frequency and a reduction at least 50% in headache intensity. Statistics used were Fisher's Exact Test and an analysis of variance. A total of 211 patients were included in this trial. One hundred ninety-seven cases, 87 males and 110 females, with a mean age of 38 +/- 13 (18-68) years, could be analysed completely (66 AO, 67 AM, 64 PL). With regard to the strictly defined primary study endpoint, no significant difference emerged between AO, AM and PL: treatment responders were 30.3% with AO, 22.4% with AM and 21.9% with PL (PAO-PL = 0.3210, PAM-PL = 1.000, PAO-AM = 0.3299 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Four against infection.

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Adverse Drug Reaction Reporting Systems↗