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C Perret

Publications and source records attributed to C Perret.

At least 163 records · Page 9Linked to original sources
PubMed1989

Time constant histograms from the forced expired volume signal: a clinical evaluation.

We evaluated a multicompartment analysis of forced expiration, based on modelling the lung as a set of twenty parallel compartments emptying exponentially with time constants ranging from 0.1-10 s; the forced expired volume signal was represented by a histogram showing the fraction of forced vital capacity as a function of compartmental time constants. We applied this technique to 80 healthy and 12 asthmatic subjects. The histograms computed from three consecutive forced expirations were poorly reproducible in 18 of the 80 healthy and 2 of the 12 asthmatic subjects. In the asthmatics, the time constant histograms conveyed no additional information on bronchial obstruction, beyond that already present in standard spirometric indices. A simulation study showed a high sensitivity of the histograms to the truncation of the terminal part of forced expiration. We conclude that the usefulness of the time constant histogram technique appears doubtful.

Adult↗
PubMed1988

[The treatment of acute cardiac insufficiency: toward a physiopathological approach].

The development of new inotropic or vasodilator agents, with different spectra of action makes possible a physiological approach to the treatment of acute cardiac failure. The choice depends on the functional disturbances measured and is then adapted to the response obtained. In the most serious cases, where pharmacological treatment proves insufficient, there need be no hesitation in using invasive methods which were formerly reserved for the treatment of cardiogenic shock. Systematic application of therapeutic formulae gives way to rational selection of the agent best adapted to the particular conditions brought about by a specified cardiopathy in a given patient.

Acute Disease↗
PubMed1988

The rat vitamin-D-dependent calcium-binding protein (9-kDa CaBP) gene. Complete nucleotide sequence and structural organization.

The structural organization of the entire rat vitamin-D-dependent calcium-binding protein (9-kDa CaBP) gene was determined by analysis of overlapping genomic clones isolated from a rat genomic library using the rat 9-kDa CaBP cDNA [Desplan C., Heidmann O., Lillie J., Auffray C. and Thomasset M. (1983) J. Biol. Chem. 258, 13502-13505]. These clones together span 30 kbp of rat genomic DNA, with the rat 9-kDa CaBP gene lying in the middle. The 9-kDa CaBP gene is 2.5 kbp long and contains three exons interrupted by two introns. The first exon contains almost the entire 5' untranslated region. The second exon codes for the calcium-binding site I, the third exon codes for site II and the 3' untranslated region. Therefore each of the calcium-binding domains is encoded by single, separate exons. The transcription initiation site was identified by S1 nuclease mapping and primer extension. A consensus sequence TATAAA is localized 31 bp upstream from the cap site and the 'CCAAT-box' lies upstream from the transcription start. Single (AC)25 and (AG)23 repeats are present in the second intron together with an Alu-like sequence. Repetitive elements are present 5 kbp upstream from the cap site and in the 3' flanking region. Comparison of the known rat CaBP sequences (9-kDa CaBP, 28-kDa CaBP, S100 protein) shows that the 9-kDa CaBP is more closely related to the S100 protein than to the 28-kDa CaBP. There is no evidence to indicate that 9-kDa CaBP has arisen from the 28-kDa CaBP.

Amino Acid Sequence↗
PubMed1988

Evolution of the EF-hand calcium-binding protein family: evidence for exon shuffling and intron insertion.

The evolutionary history of the intracellular calcium-binding protein superfamily is well documented. The members of this gene family are all believed to be derived from a common ancestor, which, itself, was the product of two successive gene duplications. In this study, we have compared and analyzed the structures of the recently described genes coding for these proteins. We propose a series of evolutionary events, which include exon shuffling and intron insertion, that could account for the evolutionary origin of all the members of this superfamily. According to this hypothesis, the ancestral gene, a product of two successive duplications, consisted of at least four exons. Each exon coding for a peptide (a calcium-binding domain) was separated by an intron that had mediated the duplication. Each distinct lineage evolved from this ancestor by genomic rearrangement, with insertion of introns being a prominent feature.

Amino Acid Sequence↗
PubMed1988

[Report on the conservative treatment of melanoma of the uvea at the Lausanne University Ophthalmologic Clinic].

A great number of techniques are currently available for the conservative treatment of uveal melanomas: ocular applicators emitting gamma rays 60Co, 125I) or high-energy beta rays (106Ru/106Rh), light photocoagulation, surgical excision, and accelerated proton beam irradiation. Life expectancy following conservative treatment is equal to or better than that following enucleation. This is demonstrated by nonrandomized comparative studies, and by the authors' own long-term results following the conservative treatment of melanomas by 60Co applicators: mortality due to metastases of small melanomas was 3% (V = smaller than 10 x 10 x 3 mm), with medium-size melanomas it was 12% (V = 10 x 10 x 3-15 x 15 x 5 mm), and with large melanomas 21% (V = larger than 15 x 15 x 5 mm). Accelerated proton beam irradiation of uveal melanomas is currently the method of choice for the conservative treatment of uveal melanomas. The sharp boundaries of the irradiated zone, the uniformly distributed irradiation dose, and beam-splitting are the main advantages of this technique. During the last three years, 310 cases of uveal melanoma have been treated in Switzerland with an accelerated proton beam. Of these, 214 were followed up for more than one year. Eight patients (3.9%) died of metastases. Visual acuity was identical or superior to initial visual acuity in 60.3% of the cases, while 39.6% exhibited a deterioration of vision or a functional loss. Favorable results achieved by conservative treatment of uveal melanomas considerably limited the indications for enucleation, which is now only performed in exceptional situations.

Brachytherapy↗
PubMed1988

Site of airway obstruction: effects on the acoustic impedance of excised pig lungs.

We investigated the relationship between the site of airway obstruction and the frequency dependence (FD) of lung acoustic impedance (ZL). The real (RL) and imaginary (XL) parts of ZL were measured by forced random noise in excised left pig lungs, before (base line) and after 1) no airway obstruction (controls, n = 10), 2) insufflation of 1-mm (B1, n = 5) or 2-mm (B2, n = 7) beads, and 3) partial reversible obstruction of lower lobar (LL) and then main-stem (MS) bronchus (n = 4). The beads caused both partial and total obstruction of airways with internal diameters of 2 mm (B1) and 2-6 mm (B2). Compared with base line, a negative FD of RL appeared from 4 to 10 Hz in LL, B1, and B2 obstructions. The FD of XL greater than 20 Hz increased in MS and LL obstruction exclusively and was the ZL feature that most clearly differentiated central from peripheral obstruction. In this experimental model, the anatomic limit distal from which obstruction no longer causes the "central" type of ZL change lies in airways with internal diameters notably greater than 2 mm.

Acoustic Impedance Tests↗
PubMed1988

Respiratory acoustical impedance: a new technique to measure airway response during bronchial inhalation challenges.

Respiratory acoustical impedance, a new method to measure airway obstruction during quiet breathing, was compared with plethysmography and spirometry in 19 asthmatics undergoing a bronchial inhalation challenge with an allergen. Respiratory acoustical impedance and plethysmography were both more sensitive than spirometry in detecting bronchoconstriction. Respiratory acoustical impedance is easily measured during quiet breathing, even in uncooperative subjects; forced expirations, which may alter bronchial tone, are avoided. Respiratory acoustical impedance is sensitive and reliable in measuring acute airway obstruction.

Acoustic Impedance Tests↗
PubMed1987

Transcriptional and post-transcriptional regulation of vitamin D-dependent calcium-binding protein gene expression in the rat duodenum by 1,25-dihydroxycholecalciferol.

Regulation of the expression of vitamin D-dependent calcium-binding protein (Mr 9000 CaBP) gene by 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) was studied in the rat duodenum. In vivo stimulation of Mr 9000 CaBP synthesis was analyzed using a complementary DNA probe and by measuring the rate of Mr 9000 CaBP gene transcription in isolated nuclei (run-on assay). A single 1,25-(OH)2D3 injection (650 pmol/100 g of body weight) induced a 2-fold increase in Mr 9000 CaBP gene transcription within 15 min in the duodenum of vitamin D-deficient rats. RNA synthesis was maximal at 1 h, then decreased until 16 h of postinjection. There was an initial transient accumulation of Mr 9000 CaBP mRNA (from 7 to 15 min), which was followed by a second, significant increase, by 3 h which remained elevated until 16 h. The magnitude and time course of the Mr 9000 CaBP increase was similar to that of its mRNA as early as 1 h after 1,25-(OH)2D3 administration. Mr 9000 CaBP gene transcription was not significantly induced by 1,25-(OH)2D3 in vitamin D-replete rats and no transient accumulation of Mr 9000 CaBP mRNA was observed. Thus, 1,25-(OH)2D3 modulates Mr 9000 CaBP gene expression in at least two ways, a rapid transcriptional stimulation and a post-transcriptional effect preventing degradation of Mr 9000 CaBP transcripts and accounting for their accumulation several hours after the hormone treatment.

Animals↗
PubMed1987

Analysis and in situ detection of cholecalcin messenger RNA (9000 Mr CaBP) in the uterus of the pregnant rat.

The molecular cloning of a cDNA fragment synthesised from rat duodenal mRNA coding for cholecalcin (calbindin), a 9000 Mr vitamin D-induced calcium-binding protein (CaBP), has been previously described. DNA/RNA hybridisation assays have been used to examine CaBP mRNA production in the uterine horns and duodena of pregnant (21 day) rats using the cloned CaBP cDNA. Northern hybridisation studies showed that the 32P cDNA sequence hybridised to a single 500-600 nucleotide species in both the uterus and the duodenum, thus demonstrating identical CaBP mRNA processing in both tissues. Dot blot hybridisation studies showed that the CaBP mRNA concentration was greatest in the duodenum while that of the uterine horns was about 10% of the duodenal level. The observed differences in CaBP mRNA levels correlate well with the in vivo CaBP concentrations. In situ hybridisation histochemistry using 3H cDNA revealed that CaBP mRNA visualised by silver grains was found in all the parts of the endometrium and the myometrium. However, CaBP mRNA was more concentrated in the outer and inner muscular fibres and in the luminal cells of the endometrium than in the stroma cells. These results demonstrate that the CaBP gene is expressed in specific cells of the rat uterus.

Animals↗
PubMed1987

Fatal cardiac arrhythmias and shock following yew leaves ingestion.

A 40-year-old woman presented with vomiting and abdominal pain following voluntary ingestion of 150 yew leaves. She developed ventricular conduction defects and arrhythmias unresponsive to medical treatment after admission. She expired five hours after yew ingestion from irreversible cardiogenic shock. More attention should be given to this rare but severe intoxication for which no effective therapy is known.

Adult↗
PubMed1987

Vitamin D-dependent calcium-binding proteins (CaBPs) in human fetuses: comparative distribution of 9K CaBP mRNA and 28K CaBP during development.

The vitamin D-dependent calcium-binding protein (CaBP) cholecalcin or calbindin, has been used as a molecular marker of 1,25-dihydroxyvitamin D3 action. Mammals possess two CaBPs: a 9,000 mol wt (9K CaBP) and a 28,000 mol wt (28K CaBP). The distinct localization of each protein in the rat has been previously described with the aid of specific radioimmunoassays developed for each CaBP. Antibodies raised against the rat 28K CaBP can be used to detect this protein in a number of mammalian species including humans. In contrast, antibodies against rat 9K CaBP do not cross react with human 9K CaBP, but human 9K CaBP mRNA can be analyzed using a cDNA probe for rat 9K CaBP mRNA. Such a cross-hybridization between the rat cDNA probe and human CaBP mRNA was demonstrated by Northern analysis. We have documented the distribution and evolution of 28K CaBP and 9K CaBP mRNA in human tissues during fetal development from 14 to 32 wk of gestation. 28K CaBP was only present in kidney and cerebellum, and not detectable in duodenum. There was a 2-fold increase of 28K CaBP in the cerebellum between 14 and 24 wk of gestation. The 9K CaBP mRNA was unevenly distributed in human fetal tissues. 9K CaBP mRNA was present in classical vitamin D target tissues such as duodenum and placenta; high levels of 9K CaBP mRNA also were found in thymus and lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Anisoylated plasminogen streptokinase activator complex versus streptokinase in acute myocardial infarction. Preliminary results of a randomised study.

25 patients with acute myocardial infarction pain lasting more than 20 minutes which was not relieved by nitrates, whose ECGs showed ST segment elevations of 1 mm or more in 2 or more ECG leads, and who presented less than 3 hours after onset of their symptoms were randomly assigned to one of 2 thrombolytic treatment groups: a single intravenous bolus of anisoylated plasminogen streptokinase activator complex (APSAC) 30U in 5 minutes or an intravenous infusion of streptokinase 1,500,000U over 60 minutes. 3 to 4 hours after the administration of the thrombolytic agent, all patients received intravenous heparin at full dosage for 24 hours. The patency of the infarct-related coronary vessels was assessed by angiography 1 to 4 hours after administration of the thrombolytic agent. Clinical signs, ECGs, pulse, blood pressure and temperature were monitored regularly for 24 hours after treatment or as clinically appropriate. APSAC seemed to be at least as effective as streptokinase in terms of patency of the infarct-related vessel (92% vs 63%, respectively). The adverse events were similar and none was life-threatening. APSAC and streptokinase caused similar falls in blood fibrinogen levels. APSAC, given as a bolus injection over 5 minutes, was easier to administer than streptokinase, which was given as an infusion during 60 minutes.

Adult↗
PubMed1987

Effects of long-term treatment with D-penicillamine on antigen-induced arthritis in rabbits: studies on in vivo articular chondrocyte damage and in vitro collagen biosynthesis by cultured chondrocytes.

The effects of a long-term (120 days) treatment with D-penicillamine (DP) (50 mg/kg/day; i.v.) on antigen-induced arthritis were studied in rabbit. They were investigated by the terminal histological examination of the joints of different groups of rabbits (unimmunized treated or untreated, immunized treated or untreated) and the study of collagen and non-collagen protein biosynthesis by cultured chondrocytes obtained from articular cartilage of the same groups of animals. Treatment with D-penicillamine diminished the intensity of the erosions of cartilage and subchondral bone, the severity of the inflammatory synovitis, and the loss of chondrocyte clusters found in cartilage sections. In cultures of chondrocytes obtained from immunized treated rabbits, a partial or complete inhibition of the decreased biosynthesis of collagen and non-collagen proteins seen in culture of chondrocytes obtained from immunized untreated animals was observed. These results show that DP could be effective in preventing damage of chondrocytes and inhibition of collagen biosynthesis in them, phenomena important in cartilage destruction induced by a chronic immunological inflammation.

Animals↗