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Biomedical subjects

J C Mercier

Publications and source records attributed to J C Mercier.

At least 91 records · Page 5Linked to original sources
PubMed1985

Construction and identification of recombinant plasmids carrying cDNAs coding for ovine alpha S1-, alpha S2-, beta-, kappa-casein and beta-lactoglobulin. Nucleotide sequence of alpha S1-casein cDNA.

An ovine mammary cDNA library has been constructed from total poly(A)+ RNA isolated from the mammary gland of a lactating ewe, using a classical procedure. Blunt-ended double-stranded cDNAs prepared with reverse transcriptase and nuclease S1 were tailed with dCTP, inserted into the dGMP-tailed PstI site of plasmid pBR322 and cloned in E. coli. Five series of homologous clones representing abundant messenger RNAs (strong hybridization with a single-stranded cDNA probe generated from total poly(A)+ RNA) were selected using each time a different predominant cloned ds-cDNA as probe, then identified by positive hybridization-translation of the cognate mRNA and subsequent immunoprecipitation and electrophoresis of the protein. The lengths of alpha s1-, alpha s2-, beta-, kappa-casein and beta-lactoglobulin mRNAs are in the range of 1.2, 1.1, 1.25, 1.0 and 0.85 kb, respectively, as determined by Northern blotting analysis. Five homologous mRNAs of similar sizes were identified in the porcine species by dot blot hybridization and Northern analyses. The nucleotide sequence of alpha s1-casein mRNA was determined by sequencing, according to Maxam and Gilbert, both a 1080 bp long cloned ds-cDNA and a ss-cDNA (268 nucleotides) generated by 5' extension of a 5' terminal truncated radiolabeled fragment (83 bp) of the relevant ds-cDNA, used as primer for reverse transcription. The 3' non coding region (431 nucleotides, excluding the poly(A) tail) represents 70% of the length of the coding region (618 nucleotides) flanked by a 61 nucleotide 5' region. Comparison of sequences of ovine and bovine, rat and guinea-pig alpha s1-casein mRNAs has revealed a greater homology in the 3' and especially 5' non coding regions. In the reading frame, the conserved regions are essentially those corresponding to the signal peptide and phosphopeptide domains. The derived 206 amino acid sequence of ovine pre-alpha s1-casein differs from that of its bovine counterpart (genetic variant B) by 24 amino acid substitutions and a deletion of 8 amino acid residues occurring in the polypeptide chain of the mature protein. Such a variation (84% homology only) in two phylogenetically closely related species indicates a high rate of evolution of alpha s1-casein.

Amino Acid Sequence↗
PubMed1984

[Neonatal syphilis despite erythromycin treatment of the mother].

A one-month old infant whose mother had been treated with erythromycin during pregnancy exhibited signs of severe congenital syphilis with collapse requiring admission to an intensive care unit. Erythromycin has low placental transfer and other treatments would have probably been more adequate. Some authors advocate the use of the latest tetracyclines and doxycycline could also be administered. The WHO's recommendations that all children born of mothers who were not treated with penicillin should receive this antibiotic after birth is still valid.

Erythromycin↗
PubMed1984

Hemolytic-uremic syndrome: an analysis of the natural history and prognostic features.

Sixty-seven children with hemolytic-uremic syndrome (HUS) were admitted between 1974 and 1981. Of these, 52 (78%) were aged less than 3 years. All children had acute renal failure and 48 (72%) required peritoneal dialysis. The etiology in twenty cases varied from bacterial and viral infections (7 and 5 cases, respectively) to renal irradiation with chemotherapy (2) and preexisting glomerulopathy (1). 5 (7%) children died during the acute phase of the illness. Long-term follow-up (mean 3 years 3 months) of 56 cases showed that 37 children (60%) had so far experienced no functional sequelae and 8 (13%) only mild sequelae while 3 (5%) were on iterative hemodialysis, 3 had severe chronic renal failure and high blood pressure (HBP) and 5 (8%) had HBP and normal kidney function. While the recovery rate was approximately 60% in all age groups, the mortality rate and serious after-effects were twice as frequent (42%) in children over 3 years of age as in those less than 3. Renal histology (total of 37) showed 12 cases of cortical necrosis, 22 of glomerular thrombotic microangiopathy (TMA) and 3 arterial TMA. Prognosis was poor for all cases of arterial TMA and 58% of those exhibiting cortical necrosis.

Acute Kidney Injury↗
PubMed1984

[Intestinal occlusion and enterocolitis caused by Gelopectose].

A case of intestinal obstruction and enterocolitis, probably as a consequence of inappropriate use of thickened feedings, is reported. Products which thicken feedings take an important part in the treatment of gastro-oesophageal reflux in infants. In order to thicken feedings, pectin and silicium have been added to milk. However, they may lead to an obstructive medication bezoar. Thus, it is necessary to limit their use to 3-5% of feeding and to clearly explain their potential hazards to the family.

Enterocolitis↗
PubMed1983

[Rhabdomyolysis and acute encephalitis in coxsackievirus infection].

We report the case of a 6 year-old boy with rhabdomyolysis involving only the inferior limbs. It was complicated by renal failure with anuria and intravenous coagulopathy and associated with encephalitis. Virologic investigations showed a recent infection due to Coxsackie B5 virus. Full recovery was observed after symptomatic treatment with peritoneal dialysis, exchange transfusion and heparin therapy.

Acute Disease↗
PubMed1982

Cell-free synthesis, proteolytic processing, core glycosylation, and amino terminal sequence of rabbit pre-alpha-lactalbumin.

Two different forms of alpha-lactalbumin were isolated from rabbit milk and partially characterized. The major and the minor species had apparent molecular weights of 18000 and 14000, respectively, according to their electrophoretic mobilities on SDS polyacrylamide gels. Analyses of their amino acid compositions and amino-and carboxy-terminal sequences did not reveal any difference, but sugar analysis showed the occurrence of carbohydrates in the major species. Rabbit alpha-lactalbumin was synthesized in a cell-free translation system as a precursor with an amino terminal extension of 19 amino acid residues whose primary structure is rather different from those of its ovine and porcine counterparts, in contrast with the extensive similarity so far observed between the known signals of homologous milk proteins. When mammary microsomal membranes were added during translation, the preprotein was converted to authentic alpha-lactalbumin, as demonstrated by amino terminal sequence analyses. However, one of the two processed forms migrated more slowly than pre-alpha-lactalbumin on SDS polyacrylamide gels and this was related to the occurrence of carbohydrates: only the "slower moving" polypeptide was specifically adsorbed on concanavalin A Sepharose and its electrophoretic mobility was enhanced after treatment with endoglycosidase H, an enzyme known to remove clustered mannosyl residues linked to di-N-acetylchitobiose. It was also observed that the rate of translocation of alpha-lactalbumin across the microsomal membrane was lower than that of beta-casein.

Amino Acid Sequence↗
PubMed1982

Amino terminal sequence, processing, and biological activity of porcine pre-alpha-lactalbumin.

Polyadenylated RNAs isolated from bound polysomes of a lactating sow's mammary gland, were translated in a cell-free system and in vitro synthesized alpha-lactalbumin was immunoprecipitated and radiosequenced. The translation product was found to contain an amino terminal extension of 19 amino acid residues, very similar to its ovine counterpart, that was selectively removed when translation was carried out in the presence of rabbit mammary microsomal membranes. Assays of porcine pre-alpha-lactalbumin for activity on galactosyltransferase showed that the preprotein can also interact with and modify the specificity of the enzyme, as indicated by de novo synthesis of lactose.

Amino Acid Sequence↗
PubMed1982

Two-dimensional echocardiographic assessment of left ventricular volumes and ejection fraction in children.

The ability of two-dimensional echocardiography to measure left ventricular volumes and ejection fraction was evaluated in 25 children with congenital heart disease. Dimensions and planimetered areas were obtained in the short-axis view at the mitral valve and high and low papillary muscle levels and in the apical two- and four-chamber views. Eight algorithms using five geometric models were assessed. Left ventricular end-diastolic volume, end-systolic volume and ejection fraction were compared with data from biplane cineangiocardiograms. The correlation varied with the algorithm used. Algorithms using short-axis views appeared superior to those using only apical long-axis views. Four algorithms estimated left ventricular volumes with equal accuracy (Simpson's rule, assuming the ventricle to be a truncated cone; Simpson's rule, assuming the ventricle to be a truncated ellipse; hemisphere cylinder; and ellipsoid biplane). The single algorithm that best estimated left ventricular ejection fraction was the ellipsoid biplane formula using the short-axis view at the papillary muscle level (r = 0.91, slope = 0.94, SEE = 6.7%). Thus, two-dimensional echocardiography can accurately assess left ventricular volumes and ejection fraction in children with congenital heart disease.

Adolescent↗
PubMed1982

Divergent effects of inotropic stimulation on the ischemic and severely depressed reperfused myocardium.

Mechanical function remains depressed for hours and days after even brief periods of ischemia. To determine whether the depressed function of the reperfused myocardium could be improved y inotropic stimulation, we studied segmental function during ischemia and after reperfusion using mercury-in-Silastic length gauges in 15 dogs. During coronary artery occlusion, segmental function could not be improved by inotropic stimulation with dopamine. Release of occlusion after 30 minutes of ischemia resulted in only slight improvement in segmental function (systolic shortening at 20% of control). After reperfusion, segmental function could be markedly enhanced by inotropic stimulation. The response to inotropic stimulation was similar after reperfusion after 3 hours of ischemia if the myocardium remained viable (nine dogs). When the myocardium was necrotic (five dogs), there was no improvement after reperfusion, either spontaneously or in response to inotropic stimulation. If applicable to humans, these results suggest that intractable pump failure caused by extensive but reversible ischemia could be effectively treated by reperfusion and inotropic stimulation.

Animals↗
PubMed1981

Early phase acute myocardial infarct size quantification: validation of the triphenyl tetrazolium chloride tissue enzyme staining technique.

Gross histochemical delineation of myocardium which has lost dehydrogenase enzyme activity has been shown to facilitate macroscopic recognition of necrotic myocardium. The present study was undertaken to assess the accuracy of the triphenyl tetrazolium chloride (TTC) technique for quantitating myocardial infarct size very early after coronary occlusion. In 16 closed-chest dogs the left anterior descending coronary artery was occluded with an intra-arterial balloon. Twelve dogs were killed 6 hours after occlusion, their hearts excised, cut from apex to base into 1 cm thick slices, and incubated in TTC. Whole-mount histologic sections of each slice were prepared. Myocardial infarct size was measured by planimetry of photographs of each gross slice and histologic section using classical criteria of necrosis. Myocardial infarct size determined in 54 slices by the TTC technique and histologically was similar (25 +/- 16% vs 27 +/- 16% of the left ventricular mass, mean +/- SD) with close correlation between the two methods (r = 0.91). Four dogs were killed 3 hours after occlusion and TTC stained and unstained myocardium was studied by electron microscopy. When the TTC technique identified necrosis so did electron microscopy. Areas identified by the TTC technique as non-necrotic were either normal or only ischemic by electron microscopy. Thus, using TTC, necrosis can be quantitated reliably 6, and even 3 hours after coronary occlusion, before histologic changes are clearly diagnostic. This technique represents a reliable, practical means for quantitation of recent infarction and for studying the evolution of ischemic injury in its early phase.

Acute Disease↗
PubMed1981

Two-dimensional echocardiographic evaluation of discrete subaortic stenosis from the apical long axis view.

M-mode standard two-dimensional (2DE) left parasternal long axis echocardiographic examination of the left ventricular outflow tract (LVOT) was evaluated exclusively with respect to its utility in identifying discrete subaortic stenosis (SUB-AS). Important details of the anatomy of the subaortic area may also be obtained from 2DE apical long axis imaging. According, 18 patients with discrete SUB-AS were prospectively evaluated by M-mode and 2DE. The M-mode findings included narrowing of the LVOT and early systolic closure of the aortic valve. However, these findings were variable and highly dependent upon scan speed, fluid flow dynamics, and beam angulation. 2DE findings varied using the standard long axis view at the left parasternal border, depending upon the type of obstruction present. A discrete membrane produced linear echoes adjacent and parallel to the interventricular septum beneath the aortic valve. Fibromuscular obstruction produced a localized dense ridge of echoes in the LVOT. These findings were not apparent in five patients studied. In these patients, the 2DE apical long axis view was employed to image the subaortic area. From this tomographic corss-section a fibrous membrane was imaged as a linear echo parallel to the aortic valve. The membrane extended across the LVOT from the ventricular septum to the anterior leaflet of the mitral valve. The 2DE apical long axis view therefore provides an additional approach in the evaluation of patients with discrete SUB-AS.

Adolescent↗