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Biomedical subjects

C Richard

Publications and source records attributed to C Richard.

At least 289 records · Page 16Linked to original sources
PubMed1986

Characterization of Flavobacterium species by analysis of volatile fatty acid production.

Seventy-four Flavobacterium strains were characterized by gas-liquid chromatographic analysis of volatile fatty acids produced in the culture medium. Principal components analysis permitted the graphic representation of the relative positions of the different strains, and aggregation according to the variance enabled a hierarchical classification to be established. The study revealed three subgroups each for F. meningosepticum and F. odoratum. Our F. breve, Flavobacterium sp. group IIb and F. multivorum strains appeared to be homogeneous. These results tallied with those of previous studies on DNA base composition and reassociation, electrophoretic protein profiles and cellular fatty acid composition.

Butyrates↗
PubMed1986

Choosing the right dose for beta-blocker treatment of hypertension: experience with tertatolol.

The determination of the optimum dosage for antihypertensive therapy, i.e. the unit dose and the administration frequency, remains one of the least discussed subjects. For beta-blockers as well as for other drugs, this determination is mainly based on the dose-effectiveness curve, the top of which corresponds to the right dose. Thus, a wide range of doses should be tested, and this as early as possible during drug development. The first step is to assess the optimum beta-blocking dose in healthy volunteers during phase I studies. These dose-response studies are usually performed according to a cross-over design. Among the many techniques proposed for assessing the effects of beta-blockers in man, isoprenaline and dynamic exercise tests are the most commonly used. The second step is to make use of the previous results to find the right dose for hypertensive patients in phase II studies. However, many individual factors which can influence the blood pressure response should be kept in mind, especially the initial blood pressure level. The choice of the design is generally based on the need to have repeated administration in order to obtain optimum control of the hypertension. Therefore, the cross-over design, although theoretically the best one, is rarely used on account of its practical and ethical problems. In contrast, the parallel design, with random assignment of treatments, is suitable to most experimental situations. Very different in nature, the stepped dose design stems from an ethical and practical approach of dose finding and thus is also widely used. Finally, correct measurement techniques of blood pressure are required.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1986

Hairy-cell leukaemia associated with auto-immune disorders in the form of a 'lupus-type' anticoagulant and a positive direct Coombs' test.

An account is given of a case of hairy-cell leukaemia associated with a 'lupus-type' anticoagulant and a positive direct Coombs' test, both of which were clinically symptom free. This is yet another example of the coexistence of hairy-cell leukaemia and an auto-immune disorder, but the disorder in question has not been described previously.

Autoantibodies↗
PubMed1986

Effect of mechanical ventilation on hepatic drug pharmacokinetics.

Mechanical ventilation was able to induce a decrease in cardiac output and regional blood flow, especially hepatic flow. Thus, hepatic elimination of drugs with a high hepatic-extraction ratio, which was linked to alteration in hepatic blood flow, could be reduced during mechanical ventilation. The aim of this work was to determine the effect of mechanical ventilation on pharmacokinetic parameters of lidocaine, which is a well-known nonrestrictive elimination drug at the hepatic level. Five patients (mean age, 58 years) with normal hepatic function and quite similar gasometric parameters before and after weaning from mechanical ventilation were studied. With a washout period of 48 hours between mechanical ventilation and spontaneous ventilation, each patient was submitted to the following protocol: lidocaine in a bolus (1.5 mg/kg intravenously), followed by infusion (1.0 to 1.7 mg/min for 120 minutes). The results were that the peak plasma concentration after the bolus during mechanical ventilation was 3.22 +/- 0.37 mg/L (mean +/- SE) vs 2.40 +/- 0.35 mg/L during spontaneous ventilation (p less than 0.02). Steady-state plasma concentration during mechanical ventilation was 2.10 +/- 0.20 mg/L vs 1.64 +/- 0.16 mg/L during spontaneous ventilation (p less than 0.01). Total clearance was 604.2 +/- 87.0 ml/min during mechanical ventilation vs 775.0 +/- 112.1 ml/min during spontaneous ventilation (p less than 0.01). Elimination half-life was 245.2 +/- 50.6 minutes during mechanical ventilation vs 160.0 +/- 40.6 minutes during spontaneous ventilation (p less than 0.05). Distribution volume was 188.6 +/- 50.2 L during mechanical ventilation and 183.0 +/- 50.8 L during spontaneous ventilation (not significant). These preliminary data clearly demonstrated a decrease in lidocaine elimination in patients submitted to mechanical ventilation, but the magnitude of dosage adjustment of such a highly hepatic-extracted drug in patients submitted to mechanical ventilation remains to be investigated.

Adult↗
PubMed1986

[Phenotype characteristics of 63 strains of Pseudomonas paucimobilis, mostly of hospital origin].

Sixty-three strains of Pseudomonas paucimobilis, a Gram-negative, lemon yellow pigmented, glucose nonfermenting bacillus are phenotypically compared to the type strain of this new species (ATCC 29837). The morphological, cultural, biochemical (ONPG-test, oxidase, aesculin positive) and nutritional (assimilation of many glucides) characteristics and susceptibility or resistance to antimicrobial agents (many antibiotics are active) are reported. The similarities and differences between P. paucimobilis and other yellow pigmented bacteria (Flavobacterium, especially group IIb, Xanthomonas, Pseudomonas maltophilia, stutzeri and cepacia) are presented. The occurrence of P. paucimobilis in diverse aquatic and aqueous sources and hospital environments and its significance in medical bacteriology (many isolates from blood cultures) are discussed.

Anti-Bacterial Agents↗
PubMed1985

Characterization of the purified molybdate-stabilized glucocorticoid receptor from rat liver. An in vitro transformable complex.

Rat liver glucocorticoid receptor was purified in the presence of molybdate by a three-step procedure comprising protamine sulfate precipitation, affinity chromatography on a dexamethasone matrix and high-performance size-exclusion chromatography (HPSEC) on a TSK G 3000 SW column. The [3H]triamcinolone-acetonide-receptor complex was obtained in 20% yield with an overall 11 800-fold purification. The dissociation rate constant of this complex was 1.6 X 10(-4) min-1. The purified receptor sedimented at 8.3 S in high-salt and 9.4 S in low-salt sucrose gradients containing molybdate. A 7.0-nm Stokes radius was determined by HPSEC on a TSK G 4000 column in high-salt buffer. The calculated Mr was 278000. Dodecyl sulfate/polyacrylamide gel electrophoresis revealed an almost homogeneous 90 000-Mr band. Three minor bands with Mr of 78 000, 72 000 and 48 000 were also inconstantly seen. An apparent pI = 5.1 was observed for the [3H]steroid complex by isoelectric focusing in agarose gel. Furthermore high-performance ion-exchange chromatography of the purified complex on a DEAE 545 LKB column (DEAE HPLC) yielded a sharp peak eluted at a 315 mM potassium ion concentration. This peak was shown to contain almost all the 90 000-Mr protein. Moreover the purified receptor complex appeared to be transformable to a DNA-binding state after molybdate removal followed by warming 30 min at 25 degrees C in presence of 0.2% bovine serum albumin: 50-78% transformation yield could be demonstrated by DNA-cellulose chromatography. Partial transformation could also be obtained at 0 degrees C in the absence of any added protein and was followed by DEAE HPLC. The transformed complex was eluted by 180 mM potassium.

Animals↗
PubMed1985

[Gram-negative bacteria in a medical resuscitation unit. Distribution of species and antibiotic sensitivity].

The distribution of Gram-negative bacilli species and their susceptibility to various antibiotics were surveyed over a 18-month period in an intensive care unit. Gram-negative bacilli were isolated from blood cultures (65), urine cultures (191), respiratory tract samples (176) or miscellaneous samples (69). The bacilli most frequently isolated from blood cultures were enterobacteriaceae (95%), including Escherichia coli (46%), Proteus (22%) and Klebsiella pneumoniae (12%). Pseudomonas aeruginosa was predominant in respiratory tract samples, and Serratia marcescens was more frequently isolated from urine cultures than from other samples. Antibiotic susceptibility testing was performed using a standard disc diffusion method. In view of the susceptibility of blood isolates to the second-generation cephalosporins we consider that these are preferable to third-generation cephalosporins for first-line antibiotic therapy of septicaemia due to Gram-negative bacilli, except for hospital-acquired infections. More than 50% of the bacilli were resistant to ampicillin; ticarcillin and mezlocillin were not very active against Klebsiella. Nalidixic acid was very active on urine isolates and therefore seems to be a good first-line antibacterial for lower urinary tract infections.

Anti-Bacterial Agents↗
PubMed1985

Prospective study of the potentiation of acenocoumarol by amiodarone.

The influence of oral amiodarone on the anticoagulant effect of the coumarin derivative acenocoumarol has been investigated prospectively in 10 patients with normal renal, hepatic and haematological function and who were not in cardiac failure. The daily dose of acenocoumarol was sufficient to produce a prothrombin activity of 25 to 35%. When the prothrombin time had become stable amiodarone 600 mg/d was administered for 1 week followed by 400 mg/d for the next 3 weeks. A decrease in prothrombin activity from 30.5 to 20.2% was observed, associated with a decrease in vitamin K coagulation factors, after a mean of 4 days following commencement of amiodarone. In 6 patients a prothrombin activity less than 20% required a 60% reduction in the dose of acenocoumarol after 1 week of amiodarone 600 mg, and a 33% reduction after 3 weeks of amiodarone 400 mg. There was no correlation between the plasma amiodarone and the decrease in prothrombin activity. Inhibition of acenocoumarol metabolism by amiodarone is the most likely explanation of these findings.

Acenocoumarol↗
PubMed1985

Comparative studies of the neurofilament triplet protein peptide mapping by chemical cleavage.

Peptide mapping of the three neurofilament protein subunits with apparent mol. weights of 210 kDa, 160 kDa and 70 kDa was performed with two different reagents: CNBr, BNPS-Skatole leading to the cleavage of methionyl and tryptophanyl bonds respectively. With BrCN we obtained two large fragments resistant to the cleavage, with mol. wts of 85 kDa for the 160 kDa and 135 kDa for the 210 kDa neurofilament proteins respectively. These fragments were located on the C-terminal part of the proteins (the tails) and correspond to specific regions responsible for their physiological identity. On the other hand, the cleavage with BNPS-Skatole at the tryptophanyl bonds gave similar patterns. The 210 kDa and 160 kDa neurofilament proteins gave a doublet of high mol. wt resistant to the cleavage, corresponding very likely to the C-terminal part and 4 fragments of mol. wt between 30 and 40 kDa corresponding to the N-terminal part. The neurofilament triplet share a common 30.5 kDa fragment located on the N-terminal part. From these peptide mapping studies, we conclude that the two neurofilament subunit proteins with mol. wts of 160 kDa and 210 kDa are different but related structures and that the CNBr characterized cleavage fragments of mol. wt 85,000 and 135 kDa are suitable polypeptides for sequence and immunological studies of the C-terminal part of these proteins.

Animals↗
PubMed1985

[Muscular involvement in Legionnaires' disease. Review of the literature apropos of 2 cases].

Two cases of Legionnaires' disease proven by seroconversion in indirect immunofluorescence are reported. Creatine phosphokinase (CPK) was increased in both patients, and one had rhabdomyolysis with acute renal failure and acute respiratory distress. A review of the literature brought out 9 other cases of rhabdomyolysis associated with Legionnaires' disease. Myalgias are an inconstant warning symptom; renal impairment is present in more than one half of the cases, and although pulmonary lesions are moderate, respiratory muscle involvement may require mechanical ventilation. In view of the severe complications of rhabdomyolysis, CPK should be systematically assayed in patients with Legionnaires' disease; 57 p. 100 of whom, according to published reports, have high CPK levels. In a retrospective study of bacterial pneumonia caused by common pathogens, we found that CPK was elevated in 31 p. 100 of the cases. The mechanism of muscular involvement is discussed.

Adult↗