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Biomedical subjects

R Bernier

Publications and source records attributed to R Bernier.

At least 37 records · Page 2Linked to original sources
PubMed1987

Plasmid stability in immobilized and free recombinant Escherichia coli JM105(pKK223-200): importance of oxygen diffusion, growth rate, and plasmid copy number.

Stability of the plasmid pKK223-200 in Escherichia coli JM105 was studied for both free and immobilized cells during continuous culture. The relationship between plasmid copy number, xylanase activity, which was coded for by the plasmid, and growth rate and culture conditions involved complex interactions which determined the plasmid stability. Generally, the plasmid stability was enhanced in cultured immobilized cells compared with free-cell cultures. This stability was associated with modified plasmid copy number, depending on the media used. Hypotheses are presented concerning the different plasmid instability kinetics observed in free-cell cultures which involve the antagonistic effects of plasmid copy number and plasmid presence on the plasmid-bearing/plasmid-free cell growth rate ratio. Both diffusional limitation in carrageenan gel beads, which is described in Theoretical Analysis of Immobilized-Cell Growth, and compartmentalized growth of immobilized cells are proposed to explain plasmid stability in immobilized cells.

Culture Media↗
PubMed1987

Preferential Utilization of Cellobiose by Thermomonospora curvata.

Thermomonospora curvata was cultivated on mineral salts medium containing glucose and cellobiose under conditions that increasingly favored the uptake of glucose. In each case cellobiose was utilized in preference to glucose and induced beta-glucosidase and endoglucanase activity. [C]glucose metabolism studies indicated that cellobiose was not cleaved by extracellular beta-glucosidase and transported as glucose. No evidence of cellobiose phosphorylase or a cellobiose-specific phosphoenolpyruvate-phosphotransferase system was observed.

Journal Article↗
PubMed1986

Self-organizing potential and morphogenetic potential (comparing current embryological and Atlan's views).

The concept of self-organizing potential proposed by Atlan, conceived within the framework of information theory, attempts to explain the emergence of the structures and functions of the organism, as well as the concept of morphogenetic potential, conceived in the embryological laboratories. Are the two theses diverging or converging and/or complementary to each other? The paper indicates, first, the context of Atlan's thesis and the meaning of his concepts of self-organization and self-organizing potential in evolutionary systems as well as in individual systems. It then develops an in-depth analysis of these individual systems and attempts to discern, in Atlan's thesis, the respective roles of the genetic factors (first at the initial stage of the system and then in the course of its development) and of the epigenetic factors in the formation of the individual, particularly during morphogenesis. This analysis reveals some difficulties inherent in the theory and induces the author to propose a few additional distinctions. Finally, the paper underlines the analogies and divergences between the concepts of self-organizing potential and morphogenetic potential.

Animals↗
PubMed1986

Prevalence of rubella antibodies in Massachusetts schoolchildren.

In 1982, 1,871 (79%) of 2,368 eligible 6th, 10th and 12th grade students in Massachusetts participated in a statewide serosurvey for rubella antibodies. Sera were screened at the Centers for Disease Control (CDC) by a reference hemagglutination inhibition assay at 1:8, equivalent to approximately 15 International Units (IU)/ml. Sera negative by the CDC hemagglutination inhibition assay were retested using an enzyme immunoassay, a passive hemagglutination assay, and a commercial hemagglutination inhibition test. The approximate screening levels were 10 IU/ml, 7.5 IU/ml, and 5 IU/ml, respectively. Overall seroprevalence levels varied from 76.4% screening at 15 IU to 93.1% including seropositives from any of the tests. Persons with a school record of vaccination had significantly higher seroprevalence levels than persons without records. However, only 78.3% of persons with a record had antibody greater than or equal to 15 IU compared with 60.0% without records; considering any detectable antibody, the comparison is 95.6% versus 71.4%. The low titers in vaccinees appeared to be due to a falloff of antibody with time since vaccination. Of students with a single vaccination noted in the record with exact dates, 92.3% who were vaccinated 0-4 years prior to the study had antibody at 15 IU compared with less than 78% of students with antibody who were vaccinated five or more years prior to the study. In contrast, using more sensitive assays, there was no significant decline in seroprevalence with time since vaccination. Revaccination studies and epidemiologic data suggest that almost all persons with detectable antibody whether above or below 15 IU/ml are immune to rubella. Thus, immunity levels in Massachusetts schoolchildren in the 6th, 10th, and 12th grades are probably in excess of 90%.

Adolescent↗
PubMed1986

Immunity against measles and rubella in Massachusetts schoolchildren.

A statewide serosurvey was conducted among 6th, 10th and 12th grade Massachusetts schoolchildren in 1982. Sera were screened using a standard measles hemagglutination inhibition (HI) assay, a sensitive measles plaque neutralization assay, and four rubella assays with corresponding sensitivity limits of approximately 15, 10, 7.5, and 5 international units (IU) of rubella antibody/ml respectively. Using the most sensitive assays, seroprevalence was 98.6% for measles antibodies and 93.1% for any rubella antibodies. For persons who received single doses of either combined measles and rubella vaccines or separate single vaccinations at different times, there were no significant differences in seroprevalence using sensitive assays. Of persons who received combined vaccines, 99.3% had antibody against measles compared to 98.4% of single antigen recipients. For rubella, 98.6% of combined vaccine recipients had antibody compared to 95.7% of single antigen recipients. These seroprevalence data indicate the effectiveness of a combined vaccination program and support epidemiologic data indicating virtual elimination of these diseases in Massachusetts schoolchildren.

Adolescent↗
PubMed1986

Long-term clinical and functional results of sleeve lobectomy for primary lung cancer.

Sleeve lobectomy is a lung-saving operation in which a portion of main bronchus is removed in continuity with the involved lobe to preserve distal parenchyma. Current controversies relate to indication and safety of the procedure, adequacy as a cancer operation, and contribution of the reimplanted lobe to overall remaining lung function. Between 1975 and 1985, sleeve lobectomy was done electively in 72 patients with lung cancer. There were no operative deaths, but major complications occurred in 10% of patients. Most resected carcinomas were squamous (65/72). Complete resection was performed in all but five patients. A minimum of 1 year's follow-up information was available for all patients. For patients with N0 disease (n = 34) the cumulative 5 year survival rate was 67%, and for patients with N1 status (n = 34) it was 60%. Although postoperative pulmonary function studies at 5 years (n = 19) show subnormal values, they were not severely altered with regard to percent of predicted (forced vital capacity, 85.9% +/- 17.5%; forced expiratory volume in 1 second, 74.9% +/- 19.4%). Regional function was determined by ventilation/perfusion isotope scanning methods. For 15 patients with right lung bronchoplasties, perfusion ratios were 41.1% right lung/58.9% left lung. For four patients with left sleeve operations, these ratios were 29.3% left lung/51.7% right lung. Washout curves show comparable ventilation between the reimplanted lobe and the contralateral lung. The data show that sleeve lobectomy is a safe and adequate operation for patients with resectable lung cancer. The reimplanted lobe or lobes contribute significantly to the overall remaining lung function.

Actuarial Analysis↗
PubMed1983

Molecular cloning of a Bacillus subtilis xylanase gene in Escherichia coli.

A gene coding for xylanase synthesis in Bacillus subtilis was isolated by direct shotgun cloning using Escherichia coli as a host. Following partial digestion of B. subtilis chromosomal DNA with PstI or EcoRI restriction enzymes, fragments ranging from 3 to 7 kb were introduced into the PstI or EcoRI sites of pBR325. Transformed colonies having lost either the ampicillin or chloramphenicol resistance markers were screened directly on 1% xylan plates. Out of 8000 transformants, ten xylanase-positive clones were identified by the clearing zone around lysozyme-treated colonies. Further characterization of one of the clones showed that the xylanase gene was present in a 3.9-kb insert within the PstI site of the plasmid pBR325. Retransformation of E. coli strain with the xylanase-positive hybrid plasmid pRH271 showed 100% transformation to xylanase production. The intracellular xylanase produced by the transformed E. coli was purified by ion exchange and gel permeation chromatography. The electrophoretic mobility of the purified xylanase indicated an Mr of 22 000.

Bacillus subtilis↗
PubMed1983

Isolation and Characterization of a Xylanase from Bacillus subtilis.

Partial characterization of an extracellular xylanase isolated by chromatography from Bacillus subtilis gave a molecular weight of 32,000 and optimum pH and temperature of 5.0 and 50 degrees C, respectively. K(m) and V(max) values, determined with a soluble larchwood xylan, were 0.16% and 7.0 x 10 mumol min mg of enzyme respectively. The amino acid composition showed more basic amino acid residues than in a previously characterized xylanase from a white-rot fungus.

Journal Article↗
PubMed1982

Diagnosis and long-term follow-up of major bronchial disruptions due to nonpenetrating trauma.

From 1966 through 1978, 13 patients were treated for major bronchial disruptions due to nonpenetrating trauma. In 10 patients the diagnosis was made early, and operation was carried out in all of them. Four of the 6 patients with main bronchus avulsion had primary repair and all 4 patients with lobar rupture underwent lobectomy. One patient had a pneumonectomy. There was 1 operative death. In 3 patients the diagnosis was made more than a month after the injury. A bronchoplastic repair was done in every patient. All 7 patients who had repair of a transected main bronchus were assessed 2 to 14 years after operation (average, 7 1/2 years). Flow-volume curves on air and air-helium were normal, indicating no major airway obstruction; this finding was confirmed by clinical and bronchoscopic examinations. Pulmonary diffusing capacity for carbon monoxide was also normal in all patients. Volume measurements by closed circuit method and by body plethysmography showed restriction in 1 patient but no major air trapping. Perfusion/ventilation scans showed homogeneous distribution of air and blood flow in the lung.

Adolescent↗
PubMed1977

Myocardial color scan with 43K in ischemic heart disease.

The value of myocardial scanning with 43K was assessed in 64 consecutive patients undergoing coronary arteriography, and in five young volunteers. Myocardial scans at rest detected only 16 of the 35 transmural infarcts documented on electrocardiograms, 11 of 11 anterior infarcts and five of 24 in other sites. Myocardial scans were obtained immediately after a graded exercise test in the five normal volunteers, in nine patients with normal coronary arteriograms and in 25 patients with atherosclerotic narrowing greater than 75% involving the left anterior descending artery, with or without disease of other coronary vessels. All patients with normal coronary arteriograms had normal myocardial scans. A regional perfusion deficit was observed after exercise in all six patients with single vessel disease, but in only 11 of the 19 patients with disease involving two or three vessels. Although the technique was specific, it lacked sensitivity, due mostly to poor resolution and the location of the disease.

Adult↗