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Biomedical subjects

R Frank

Publications and source records attributed to R Frank.

At least 487 records · Page 27Linked to original sources
PubMed1983

Protoplast and cytoplasmic membrane preparations from Streptococcus sanguis and Streptococcus mutans.

Protoplasts were prepared from Streptococcus sanguis and some S. mutans serotypes by use of lysozyme (EC 3.2.1.17) under particular conditions: cells had to be grown in DL-threonine (20 mM) and harvested in early exponential phase. The efficiency of protoplast formation was enhanced by two additional steps: plasmolysis (in 12% PEG), prior to addition of lysozyme, and a swirling phase, after the enzymic action. This procedure allowed us to obtain clean protoplasts, with only 0.5% contamination by bacterial cell walls. Up to 90% protoplast lysis was obtained in 0.5 M-NaCl. Cytoplasmic membrane purification was achieved by centrifugation on a glycerol cushion.

Bacteriological Techniques↗
PubMed1983

Common antigens of streptococcal and nonstreptococcal oral bacteria: characterization of wall-associated protein and comparison with extracellular protein antigen.

A soluble wall-associated common protein (WAP) has been isolated from cell wall-extracted antigens of exponentially growing cells of Streptococcus sanguis OMZ9, two serotypes (a and e), of Streptococcus mutans and Actinomyces viscosus OMZ104. The WAP antigens from the different strains were obtained by chromatography on an anti-rabbit immunoglobulin column of sodium dodecyl sulfate-dissociated immunoprecipitates. The affinity-isolated WAP antigens from the different oral bacteria were identical, as demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (showing an apparent molecular weight of 80,000) and amino acid and sugar compositions. This WAP antigen, common to all bacterial strains tested, consisted of 90% protein and 10% sugar. A comparison of the chemical properties of this WAP antigen and of the soluble extracellular common protein antigen showed that, although having similar amino acid and sugar compositions, the two proteins are different. Electron micrographs developed after immunocytological labeling of the WAP antigen on whole cells confirmed that it is located on the cell wall.

Actinomyces↗
PubMed1983

Health issues in the Clean Air Act.

Major conclusions and recommendations of the National Commission on Air Quality on issues of health in the Clean Air Act are presented. The issues revolve mainly about the standard setting processes for ubiquitous pollutants, controlled through ambient air quality standards (Section 109), and for hazardous pollutants controlled through emission standards (Section 112). The conceptual difficulties inherent in the terms "adequate margin of safety" (Section 109) and "ample margin of safety" (Section 112) are discussed. The Clean Air Science Advisory Committee is widely viewed as having a salutary effect on standard setting. The need for maintaining strong research capabilities within the Environmental Protection Agency that are reasonably buffered against sudden disruptive events is emphasized. Mechanisms for achieving this goal through special congressional appropriations are considered.

Air Pollution↗
PubMed1983

Residues of polychlorinated phenols and anisoles in broilers raised on contaminated woodshaving litter.

Broilers were raised for 8 weeks on litter made up of woodshavings containing high (700 micrograms/g) levels of contamination with polychlorinated phenols (PCP). The PCP levels declined in the litter over the test period while polychlorinated anisoles (PCA) increased in the highly contaminated litter. Final weights of the birds was only slightly different; however, feed conversion was slightly higher for those birds raised in the highly contaminated pens. Panelists rated the cooked samples from the birds raised on highly contaminated litter significantly lower for flavor and overall acceptability than either of the lower PCP level treatments. Residues of the odiferous pentechloroanisole were present in muscle and fat of the birds raised on the highly contaminated litter; however, residues in muscles of the birds on low level contaminated litter could not be detected. Polychlorinated anisoles were present in the fat of birds raised on normal litter but adjacent to the contaminated pens.

Animals↗
PubMed1983

[Ventricular pre-excitation revealed by idioventricular rhythm and large QRS tachycardias. Apropos of an operated case].

A 15 year old boy presented with palpitations of sudden onset and termination over a two month period. The heart was clinically and radiologically normal. The electrocardiogramme showed sinus rhythm with a short PR interval (0,11 sec) and narrow QRS complexes (0,08 sec) associated with an intermittent escape accelerated idioventricular rhythm (AIVR). During an attack of palpitations a regular tachycardia (250/min) with wide QRS complexes of the same configuration as those of the AIVR (left side delay). The diagnosis of ventricular tachycardia was retained. Endocavitary electrophysiological recording demonstrated preexcitation of the right ventricle associated with accelerated nodal conduction explaining the narrow QRS complexes in sinus rhythm. The wide complex tachycardias initiated and terminated by paired ventricular stimulation were identical to the spontaneous attacks and were attributed to an antidromic reciprocating rhythm. The hypothesis of a rhythm arising from the accessory pathway is suggested. This would explain the identical configuration of the QRS complexes of the AIVR and of the antidromic reciprocating-rhythm and the disappearance of the AIVR after surgical section of the accessory pathway.

Adolescent↗
PubMed1983

[Torsades de pointes initiated by slow ventricular stimulation].

The authors report a case of isolated and probably congenital complete heart block with spontaneous torsades de pointes preceded by an increase in the QT interval. During positioning of a temporary pacing catheter mechanically induced extrasystoles were observed, which seem to favor ventricular extrasystoles and unsustained runs of torsades de pointes. When the basal rhythm showed no extrasystoles, electrical stimulation delivered late in diastole captured the ventricle normally and was then followed in reproducible fashion by episodes of torsades de pointes or minor equivalents. The mechanism of this phenomenon is thought to be related to a concealed phase 4 intramyocardial block. It may have important practical consequences in paced patients predisposed to torsades de pointes. If the pacemaker is programmed at too slow a rate, with stimulation falling late in diastole, torsades de pointes could occur, some attacks of which are known to degenerate to true ventricular fibrillation.

Cardiac Pacing, Artificial↗
PubMed1983

[Evaluation of the response to the ajmaline test in the diagnosis of paroxysmal atrioventricular blocks].

Between October 1973 and December 1981, 31 symptomatic patients who underwent pacemaker therapy on the results of a positive Ajmaline test alone, showing infrahisian AV block, were followed up clinically and electrocardiographically. The mean follow up from the date of implantation was 30 months. Two groups of patients were identified according to the results of electrophysiological investigations and clinical and electrocardiographic follow-up: --group I: 13 patients with either infrahisian AV block or an HV interval greater than or equal to 120 ms after Ajmaline; --group II: 18 patients with an HV interval less than 120 ms after Ajmaline. During follow-up, the 5 AV blocks observed out of the 7 documented at inhibition of the pacemaker and the only two cases of deterioration of the intraventricular conduction during sinus rhythm occurred in Group I. The only discriminating variable between the two groups before the implantation of a pacemaker was the response to the Ajmaline test. The difference of the results of the electrical outcome between the two groups was statistically significant (p less than 0,03). During the same study period this critical value was observed in 49 other patients with a basal HV greater than or equal to 70 ms. In this group, 20 developed infrahisian AV block after Ajmaline, 26 had a HV interval greater than or equal to 120 ms and only 3 cases had HV intervals of 100 ms. These results suggest that a HV interval greater than or equal to 120 ms after Ajmaline has the same significance as infrahisian block produced by the drug.

Aged↗
PubMed1983

Exposure to Leptospira icterohaemorrhagiae in inner-city and suburban children: a serologic comparison.

This study explores the exposure of urban children to the spirochete Leptospira icterohaemorrhagiae. This organism is carried by 90 percent of the rats in Detroit. It is felt that these rats are a potential vehicle for childhood exposure to this organism. Strain-specific tests were performed comparing antibody levels in sera of inner-city (exposed) and suburban (unexposed) children. Study and control groups, numbering 124 and 113, respectively, showed significant serologic differences, with urban children having higher antibody titers. The findings are indicative of differential exposure rates and suggest that actual cases of leptospirosis may be present, yet undiagnosed.

Antibodies, Bacterial↗
PubMed1982

Ultrafast sequencing of oligodeoxyribonucleotides by FAB-mass spectrometry.

A fully instrumental method is described for the bidirectional sequencing of oligodeoxyribonucleotides. The method makes use of the negative ion fragmentation patterns of fast atom bombardment mass spectrometry. It is less time consuming than any other sequencing procedure known to date. Since one sequencing run takes as little as one hour, this new method is anticipated to cut down considerably the time required for the controlled synthesis of oligodeoxyribonucleotides of (currently) up to ten nucleotide units in length.

Base Sequence↗
PubMed1982

[Preventive treatments of tachycardias in Wolff-Parkinson-White syndrome].

Tachycardias in Wolff-Parkinson-White syndrome are due to the presence of an accessory conduction pathway between atria and ventricles. Many patients are treated with anti-arrhythmic drugs alone or in combinations. In difficult cases, the choice of therapy is guided by investigatory methods using Holter's recording system and intracavitary electrophysiological techniques, sometimes associated with special pacemakers arresting reciprocal rhythm. Intolerance to such pacemakers or failure of medical treatments usually leads to surgery. Division of the accessory conduction pathway constitutes a radical treatment of the syndrome with satisfactory results when performed by trained teams.

Anti-Arrhythmia Agents↗
PubMed1982

[The social background of obese children].

Personal data (family situation, father's profession, working vs non-working mother, type of school) of 129 Bavarian children hospitalised for obesity were compared with data from children of the Bavarian population as a whole. Obese children were overrepresented in the low and in the upper socio-economic class. Pupils in special schools were overrepresented. One-parent families were overrepresented (22% vs 14% in the overall population). There is a high proportion of divorces. The percentage of working mothers corresponds with the percentage of working mothers in the overall population. The awareness of obesity as a disease seems to be class-specific. The results of treatment depend on the attitude of the parents.

Adolescent↗
PubMed1982

Bronchoconstrictor responses to sulfur dioxide or sulfur dioxide plus sodium chloride droplets in allergic, nonasthmatic adolescent.

Eight atopic adolescent subjects without diagnosis of clinical asthma but with signs of hyperactive airways were studied. The subjects were exposed for 30 min at rest followed by 10 min during moderate exercise on a treadmill to the following: (1) filtered air, (2) 1 mg/m3 NaCl droplet aerosol, (3) 1 ppm SO2 and NaCl droplet aerosol, or (4) 1 ppm SO2. All exposures were at 75% relative humidity and 22 degrees C. Exposures to either SO2 mode produced statistically significant changes in pulmonary function, whereas sham exposures to air on NaCl did not. These results are similar to those seen earlier in a group of extrinsic asthmatic adolescent subjects and are three to 22 times greater than changes we saw in a group of normal adolescent subjects. The changes seen after inhalation of SO2 were not statistically different from those seen after inhalation of SO2 and NaCl droplet aerosol. Our results indicate that inhalation of 1 ppm SO2 by a group of atopic adolescents can produce exercise-induced bronchospasm at a level of exercise that has no effect by itself.

Adolescent↗
PubMed1982

Common antigens of streptococcal and non-streptococcal oral bacteria: isolation and biochemical characterization of the extracellular protein antigen.

An extracellular soluble common protein (ECP) has been purified from extracellular soluble fractions of exponential phase cultures of Streptococcus sanguis OMZ9, of a representative strain of each of Bratthall's seven serological groups of Streptococcus mutans, and of one strain each of Lactobacillus salivarius and Actinomyces viscosus. The ECP antigens from the different strains were prepared from SDS-dissociated immunoprecipitates by affinity chromatography on an anti-rabbit immunoglobulin column. The identity of such purified ECP antigens was demonstrated by their behaviour in immunodiffusion analysis, in SDS-PAGE, in which an identical molecular weight (60000) was found, and by virtue of their similar amino acid and sugar compositions. This common antigen (ECP) consisted of 90% protein and 10% sugar.

Actinomyces↗