Search PubMed⌕ Search

Biomedical subjects

R Weinberg

Publications and source records attributed to R Weinberg.

At least 55 records · Page 3Linked to original sources
PubMed1988

Protective immunity against avian influenza induced by a fowlpox virus recombinant.

Fowlpox virus, the prototypic virus of the genus Avipoxvirus has a natural host range limited to avian species. As such, fowlpox virus provides a suitable candidate for the development of a species-specific recombinant viral vector. This paper reports the development of a fowlpox virus recombinant expressing the haemagglutinin molecule from a highly virulent avian influenza virus. On immunization of chickens and turkeys with the recombinant, protection is afforded against a lethal challenge with either the homologous or a heterologous influenza virus strain.

Animals↗
PubMed1988

Orthodontic bonding to porcelain--bond strength and refinishing.

Glazed porcelain surfaces are not amenable to resin penetration for orthodontic bonding. The aims of this study were to evaluate (1) the bond strengths of two orthodontic composite materials to treated porcelain surfaces, (2) the effect of thermocycling, and (3) the porcelain surfaces after refinishing. Sixty glazed porcelain disks were assigned to three surface treatment groups: Silane (S), roughening and silane (RS), and roughening (R). The acid-etched enamel surfaces of 20 extracted teeth served as a control group. Ten specimens in each group were bonded with either Concise or System 1. They were stored in water at 37 degrees C or thermocycled 8 degrees to 45 degrees C. Shear bond strength was tested with an Instron testing machine (0.05 cm/min). Analysis of variance showed that the four surface treatment groups and the two composite materials produced significantly different bond strengths (P less than 0.01 and P less than 0.05, respectively). The effect of thermocycling was not significant (P greater than 0.05). Acid-etched enamel/Concise produced the highest mean bond strength (17.4 MN/m2). This was significantly greater (P less than 0.05) than the mean bond strengths of S/Concise (11.1), RS/System 1 (8.6), RS/Concise (8.1), and enamel/System 1 (7.8). The latter four mean bond strengths in turn were significantly greater (P less than 0.05) than S/System 1 (2.5), R/Concise (2.1), and R/System 1 (1.8). Of the four refinishing systems evaluated, all produced smooth surfaces but were unable to reproduce a glazed appearance. Roughening of porcelain and the silane treatment achieve bond strengths that should be clinically successful.(ABSTRACT TRUNCATED AT 250 WORDS)

Adhesives↗
PubMed1988

Chemomechanical caries removal--a clinical evaluation.

The aim of this investigation was to evaluate the efficacy and convenience of decayed dentine removal with N-monochloro-DL-2 aminobutyrate (CARIDEX) in all classes of cavities. Fifty-seven patients, each with two teeth having similarly sized carious cavities, participated in this study. One cavity in each patient was treated with the chemomechanical CARIDEX technique and the other cavity was treated with conventional mechanical drilling. The cavities were restored with either amalgam, composite or glass ionomer restorative materials. The time taken for access and caries removal was noted and the efficacy of caries removal with each technique was evaluated. The chemomechanical caries removal technique was effective in removing 90-100% of decayed dentine in 98% of the cavities treated. Multiple regression adjusted access and caries removal time to account for volume of caries removed. This adjusted time was operator dependent, and ranged from 4 to 10 minutes longer for CARIDEX than for the conventional technique. Ninety-three per cent of patients preferred the chemomechanical method of caries removal over the conventional technique (highly significant P less than 0.001). Even though the chemomechanical removal of caries is slower than the conventional technique, the efficacy of CARIDEX and its high patient acceptance provides a viable alternative method for dentinal caries removal in all classes of cavities.

Adolescent↗
PubMed1988

Analytic and preparative separation of apolipoproteins A-I, A-II, and A-IV by reverse phase high pressure liquid chromatography.

We have developed a rapid reverse phase high pressure liquid chromatographic technique capable of separating apolipoproteins A-I, A-II, and A-IV and their constituent isoforms. The separations were performed on a 30 cm x 3.9 mm C18 reverse-phase silica-based column (Waters Associates) using a 47-55% gradient of acetonitrile in 0.1% trifluoroacetic acid. Injection of a mixture of equal weights of apolipoproteins A-I, A-II, and A-IV yielded a single peak for apoA-IV, two peaks of apoA-I isoforms, and three peaks of apoA-II isoforms, with negligible overlap of each peak. When applied to the isolation of apoA-IV from a crude protein mixture obtained by incubation of phospholipid-triglyceride emulsion particles with lipoprotein-depleted plasma, the technique yielded a single peak of highly pure apoA-IV cleanly separated from isoforms of apoA-I and higher molecular weight proteins. A positive linear correlation was observed between apoprotein hydrophobicity and column retention time, thus indicating that the system provided a true reverse phase separation. We conclude that reverse phase high pressure liquid chromatography can separate human apolipoprotein A-IV from isoforms of apoA-I and apoA-II on the basis of differences in mean molecular hydrophobicity. The technique has direct application to the isolation of human apolipoprotein A-IV.

Apolipoprotein A-I↗
PubMed1987

Managing orthodontic data on a small computer.

A literature survey of file management, relational database management, and network/hierarchical database management systems led to selection of dBASE III to manage patient records on an IBM PC in the Department of Orthodontics at the Louisiana State University School of Dentistry. The versatility of this system's internal language enables ad hoc analysis of clinical and personal data to meet both anticipated and unanticipated management and scientific needs.

Computers↗
PubMed1987

Using perceived exertion to prescribe and monitor exercise training heart rate.

We examined whether feedback of heart rate (HR) or HR combined with ratings of perceived exertion (RPE and HR) during a graded exercise test (GXT) and during early trials of field training would reduce the errors commonly seen when training heart rate range (THR) is self-monitored by participants. Asymptomatic males (n = 24) were tested on a Balke treadmill protocol in a randomized, between-groups design under control conditions or conditions where feedback about HR or HR combined with RPE were given as age-predicted THR was approximated. This was followed on alternating days by three field trials of an 800-m jog where errors between prescribed and attained THR were fed back to each subject. A priori 95% confidence intervals for the first field trial showed that signed (algebraic) error for the HR combined with RPE condition (+3 bts/min) was less than for controls (+23.5 bts/min). Feedback of HR alone was no different from the control condition. All groups showed increased accuracy (P less than .05) by the third field trial [absolute error: T1 (18 bts/min) to T3 (9.6 bts/min); signed error: T1 (+14 bts/min) to T3 (+4 bts/min)]. Our results suggest feedback of HR combined with RPE during a GXT may reduce an overshoot in THR during the first of subsequent exercise sessions. Feedback of HR alone appeared sufficient to further reduce THR errors after a third exercise session in the field. The procedures used may have practical importance for sedentary, unfit, or diseased individuals where conservative HR prescriptions are desirable but electronic monitoring is not feasible or cost effective.

Adult↗
PubMed1987

The effectiveness of opaquer and color-modifier materials: a laboratory study.

New, direct bonding composite resin products are available for esthetic and restorative dentistry. As in vitro study was conducted to evaluate the stain-masking effectiveness of 57 opaquers or color modifiers. Results of the testing on 265 specimens are reported, ranging from minimal to excellent masking.

Chemical Phenomena↗
PubMed1986

Effect of the bacterial DNA gyrase inhibitors, novobiocin, nalidixic acid, and oxolinic acid, on oxidative phosphorylation.

When incubated with isolated intact rat liver mitochondria, novobiocin and nalidixic acid act as uncouplers of oxidative phosphorylation; they stimulate oxygen uptake and inhibit ATP synthesis. Novobiocin is about as powerful an uncoupler as is 2,4-dinitrophenol, nalidixic acid is somewhat less powerful, and oxolinic acid exerts no inhibition whatsoever at the concentrations used. The three inhibitors are without effect on oxidative phosphorylation in Escherichia coli nor does novobiocin affect this process in a novobiocin-permeable mutant of yeast. While it would appear that oxolinic acid may be a relatively specific tool for the manipulation of the superhelicity of DNA in complex systems such as mammalian mitochondria and intact mammalian cells, the specificity of each of these inhibitors may depend upon the particular conditions and species used and such experiments require adequate controls on oxidative phosphorylation.

Animals↗
PubMed1986

Retention of orthodontic bands with new fluoride-releasing cements.

The prevalence of enamel decalcification beneath orthodontic bands has indicated the need for a fluoride-releasing, enamel-adhesive orthodontic luting cement. The purpose of this study was to compare the retentive bond strengths of orthodontic bands cemented with two new fluoride-releasing cements, a zinc polycarboxylate and a glass ionomer, with the retentive bond strength of bands cemented with the standard orthodontic cement zinc phosphate. The site of cement failure was also evaluated. One hundred eighty extracted human molar teeth were embedded in resin blocks and randomly assigned to three cement groups. Adapted bands were cemented by a clinically acceptable technique. The cemented teeth were then assigned to one of three time intervals--24 hours, 7 days, and 60 days--and thermocycled in synthetic saliva. The force required to initially fracture the cement bond was used as a measure of cement retention. By means of the Instron, a tensile load was applied to each cemented band. The maximum retentive strength (cement failure) was interpreted from the stress-strain curve at the point where linearity deviated. The failure site was judged subjectively: between cement and enamel, within the cement, or between cement and the band. Using stress at failure, an analysis of variance showed no significant differences among the retentive strengths of the three cements. The chi-square test revealed a significant difference (P less than 0.01) between failure sites of the zinc phosphate and glass ionomer cements. Significantly more bands cemented with the glass ionomer failed at the cement/band interface, leaving the cement adhered to the tooth.(ABSTRACT TRUNCATED AT 250 WORDS)

Delayed-Action Preparations↗
PubMed1986

Sensitometric and image analysis of T-grain film.

The new Kodak T-grain film is the result of a new technology that makes fast films with high image resolution. The purpose of the investigation was to determine the sensitometric properties and image quality of a T-grain film (T-Mat G) and also to compare this film with a green-sensitive orthochromatic film (Ortho G) and a blue-sensitive film (XRP). The criteria for film evaluation were relative speed, average contrast, exposure latitude, and image resolution. The results showed that the T-Mat G film is twice as fast as the X-Omat RP film and, one and one-third times as fast as the Ortho G film. T-Mat G also produces high resolution and high contrast. This is contrary to the widely held notion that speed is inversely proportional to image quality.

Absorptiometry, Photon↗
PubMed1986

The presence of anti-HBc in a dental school patient population.

Testing for three serum markers in screening for hepatitis B disclosed 34 of 292 patients testing positive to anti-HBc. Responses to the medical history alone disclosed only one patient with a history of hepatitis. Seroanalysis, plus a complete history, yields the most reliable results.

Adolescent↗
PubMed1986

The predictive validity of the functional capacities evaluation.

This study tested the predictive validity of the Functional Capacities Evaluation (FCE), which included the following three components: a Medical History Review, a Client Activity Interview, and the Smith Physical Capacities Evaluation (SMITH-PCE) as the performance component. The FCE is used in conjunction with the Physical Demands and Environmental Conditions specified by the U.S. Department of Labor to predict a subject's ability to return to work. The study used a random sample of 52 subjects. An employment questionnaire served as a criterion measure of predictive validity. The data from the questionnaires were compared with predictions from the evaluations, and a lambdab test was applied to the data. Results suggested that for the sample analyzed, trained registered occupational therapists could use the FCE to predict a client's ability to return to work more accurately. The study was limited in that the sample used was drawn from clients seen in only one private practice and that only 42% of the questionnaires were returned.

Adult↗
PubMed1985

Force degradation of orthodontic elastomeric chains--a product comparison study.

In the last 20 years, synthetic elastic modules have been introduced to the orthodontist. However, force decay of these materials has been a clinical problem and the purpose of this project was to evaluate the force decay patterns of three commercially available elastomeric products--Ormco Power Chain II, Rocky Mountain Energy Chain, and TP Elast-O Chain--in a simulated oral environment. Thermal-cycled samples experienced less force decay over a 21-day period than samples stored at 37 degrees C. Furthermore, statistical analysis confirmed that there was a highly significant difference (p less than 0.01) between the mean force exerted by short modules and long modules for each material. Overall, modules producing higher initial forces (short modules) underwent less force decay after 21 days than did modules producing lower initial force values (long modules). All materials exerted 216 to 459 grams of force initially. After 21 days of simulated tooth movement, the force exerted by the elastic modules was 70 to 230 grams--a significant reduction (p less than 0.001).

Elasticity↗