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Biomedical subjects

R Barth

Publications and source records attributed to R Barth.

At least 73 records · Page 4Linked to original sources
PubMed1986

Validation of an in vitro assay for the determination of rabies antigen.

The modified antibody binding test, an in vitro method, was validated by a number of studies and was used as a reliable method for in process controls in the manufacture of rabies vaccines for man and animals over the last 6 years. A calculation was made showing the number of laboratory mice which were not needed for animal experiments because these were substituted by the in vitro method mentioned above.

Animal Testing Alternatives↗
PubMed1985

[New special eyeglass lens for emmetropic presbyopes].

Emmetropic presbyopes are not used to wearing bifocal or progressive-power lenses all the time. Reading spectacles have the disadvantage that they have to be removed when the wearer wishes to look into the distance. Therefore, these people are turning increasingly to pulpit spectacles, which correct their vision for reading while leaving the long-range vision to which they are accustomed unchanged. However, conventional pulpit spectacles do not enable emmetropic presbyopes to see clearly at intermediate distances. This article deals with a type of pulpit spectacles which have been specially developed for emmetropic presbyopes. The glasses have an aspheric surface which provides for clear vision at reading distance as well as at all intermediate distances.

Eyeglasses↗
PubMed1985

Effect of dietary ascorbic acid on the incidence of spontaneous mammary tumors in RIII mice.

A study of the effect of different amounts of L-ascorbic acid (vitamin C), between 0.076% and 8.3%, contained in the food has been carried out with ten groups of RIII mice (seven ascorbic acid and three control groups), with 50 mice in each group. With an increase in the amount of ascorbic acid there is a highly significant decrease in the first-order rate constant for appearance of the first spontaneous mammary tumor after the lag time to detection by palpation. There is also an increase in the lag time. The mean body weight and mean food intake were not significantly different for the seven ascorbic acid groups. Striking differences were observed between the 0.076% ascorbic acid and the control groups (which synthesize the vitamin): smaller food intake, decreased lag time, and increased rate constant of appearance of the first mammary tumor. This comparison cannot be made experimentally for guinea pigs and primates because the control groups would develop scurvy.

Animals↗
PubMed1984

Purification of a neutral proteinase, associated with the actomyosin complex, from uterine myometrium.

We have purified and characterized a neutral proteinase activity from pig uterine myometrium. The proteinase co-purified with the actomyosin complex and could only be separated from it by a high concentration of a chaotropic ion, 3M-NaBr. The proteinase was further purified by gel filtration and affinity chromatography. The purified protein showed a single band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis corresponding to an Mr of 28 000. Gel filtration on Sephadex G-100 in a buffer containing 3M-NaBr gave an Mr of 27 500. Without the addition of the chaotropic Br- ion, the proteinase aggregates to high-Mr forms of more than 10(6)Da. The proteinase has optimum hydrolytic activity with casein as substrate at pH 7.5-8.0. The thiol-group-blocking reagents p-chloromercuribenzoate, p-chloromercuribenzenesulphonate and Hg2+, as well as soya-bean trypsin inhibitor and 4-aminobenzamidine, inhibited the proteinase. Other bivalent cations, chelating agents and the serine-specific reagents 7-amino-1-chloro-3-tosylamido-L-heptan-2-one and phenylmethanesulphonyl fluoride were without any effect on proteinase activity. The proteinase degraded myosin very rapidly at a molar ratio of proteinase to myosin of 1:50, concomitant with the rate of loss of the ATPase activity. Compared with myosin, actin was only a poor substrate and was degraded at a much lower rate, even at a high molar ratio of the proteinase to actin.

Actins↗
PubMed1984

Cathepsin D from pig myometrium. Characterization of the proteinase.

The purification of cathepsin D from pig uterus by two-step affinity chromatography on concanavalin A- and pepstatin-Sepharose was described previously [Afting & Becker (1981) Biochem. J. 197, 519-522]. In this paper, chemical and physical properties of the proteinase are presented. The purified enzyme showed three bands on SDS (sodium dodecyl sulphate)/polyacrylamide-gel electrophoresis, one main band corresponding to an Mr of 31 000 and two minor bands with Mr values of 43 000 and 15 000 respectively. Gel filtration on Bio-gel P-150 and sedimentation-diffusion equilibrium studies give an Mr for the main band of about 35 000. The pI of the enzyme was determined to be 7.2. Haemoglobin was the best substrate, with a Km value of 6.4 X 10(-6)M. It was hydrolysed with a pH optimum between 3.0 and 3.3 for a substrate concentration of 100 microM. The proteinase was stable over the pH range of 3.5-6.5. At pH 6 the enzyme showed stability up to a temperature of 50 degrees C; at pH 3 the activity was already decreased below 40 degrees C. Carbohydrate studies resulted in the staining of all three bands on an SDS/polyacrylamide gel by thymol/H2SO4. After treatment with endo-beta-N-acetylglucosaminidase H, all three bands were shifted to a region of lower Mr. Of various inhibitors tested, only pepstatin was strongly inhibiting, with a Ki of 2.1 X 10(-9)M.

Animals↗
PubMed1984

A new inactivated tissue culture rabies vaccine for use in man. Evaluation of PCEC-vaccine by laboratory tests.

A new inactivated rabies vaccine (purified chick embryo cell vaccine) has been developed using the Flury LEP-C 25 strain of rabies virus propagated in primary chick embryo cell cultures. The antigen was purified and concentrated by continuous density gradient centrifugation and inactivated by betapropiolactone. This vaccine was tested for innocuity, tolerability and protective capacity in a series of laboratory tests and compared with human diploid cell strain (HDC)-vaccines of similar antigenicity. The results indicated that this new vaccine was excellently tolerated and that its protective activity met the high standard of HDC-vaccine, conditions which were imposed on this vaccine before entering clinical trials in man.

Animals↗
PubMed1984

Clinical trials in healthy volunteers with the new purified chick embryo cell rabies vaccine for man.

Behringwerke has developed the new, safe and economical purified chick embryo cell (PCEC) rabies vaccine. Due to the purification by zonal centrifugation the compatibility of this vaccine is excellent. Among 933 vaccinations in 219 healthy volunteers the only side-effect was mild pain at the injection-site in 17 vaccinations (1.7 per cent). The sero-conversion of PCEC rabies vaccine was 100 per cent in the tested healthy volunteers. The kinetics of antibody induction after PCEC rabies vaccine is comparable to antibody induction after HDC rabies vaccine. PCEC rabies vaccine induces cellular immunity as measured in lymphocyte transformation test, but no interferon activity.

Adolescent↗
PubMed1984

Purified chick embryo cell (PCEC) rabies vaccine for human use. Laboratory data.

A new inactivated rabies vaccine (Purified Chick Embryo Cell vaccine) for use in humans has been developed. The FLURY-LEP C25 strain of rabies virus was adapted to propagate in primary chick embryo cell cultures. The antigen was purified and concentrated by continuous density gradient centrifugation and inactivated by Betapropiolactone. The PCEC-rabies vaccine was tested for innocuity, tolerability and protective capacity in a series of laboratory tests and compared with Human Diploid Cell Strain rabies vaccine (HDCSV) of similar antigenicity. The results of the laboratory tests indicated that this new vaccine was excellently tolerated and that its protective activity met the high standard of HDCS-vaccine, conditions which were imposed on the PCEC-vaccine before clinical trials in man were initiated.

Animals↗
PubMed1983

Profile analysis of volcano field ionization mass spectra of urine from mice with sarcoma I transplanted by intraperitoneal inoculation.

A group of 20 inbred mice were inoculated intraperitoneally with sarcoma I cells. Urine specimens were collected before and after inoculation from this group as well as from a group of 20 mice for controls. Mass profiles of these groups were obtained by volcano field ion mass spectrometry and compared. Significant differences in average normalized mass peaks between the two groups after inoculations are observed for most of the peaks analysed from mass 84 to 313. There is sufficient diagnostic power in the mass profiles to permit unambiguous separation of the diseased mice from the healthy ones.

Animals↗
PubMed1983

Effect on the retina of an air cushion in the anterior chamber and coaxial illumination.

In an attempt to minimize the danger of light-induced maculopathy during cataract surgery with intraocular lens implantation, we assessed the refractive power of a posterior chamber lens inserted with its convex surface forward (Procedure 1) and with its plano surface placed forward (Procedure 2). In both procedures, a large air bubble is placed in the anterior chamber while the corneoscleral wound is being sutured. With the convex surface forward, parallel rays of light focus 23.6 mm behind the intraocular lens and 5 mm behind the retina. For a pupil 5 mm wide, the diameter of the beam on the retina is 1.03 mm; for a pupil 2 mm wide, the beam is 0.41 mm wide. With the plano surface forward, the refracting surface is in contact with water and its power is therefore reduced. Parallel rays of light focus 97.3 mm behind the intraocular lens and 79.6 mm behind the retina. For a pupil 5 mm wide, the diameter of the beam on the retina is 4.14 mm; for a pupil 2 mm wide, the beam is 1.66 mm wide. Thus, the intensity of the radiation experienced by the retina per surface unit is only 6.19% of that produced when the convex surface is forward.

Air↗
PubMed1982

Mouse c-myc oncogene is located on chromosome 15 and translocated to chromosome 12 in plasmacytomas.

Hybridization studies with viral oncogene probes indicate that c-myc, the cellular gene homologous to the transforming gene of avian myelocytomatosis virus, resides on mouse chromosome 15 and in many plasmacytomas is translocated to the antibody heavy chain gene locus on chromosome 12. The transcriptional orientation of the translocated c-myc sequence is opposite the orientation of the adjacent C alpha gene that codes for the heavy chain of immunoglobulin A. The translocated c-myc sequence is not the same oncogene detected in urine plasmacytomas by the NIH-3T3 cell transformation assay.

Animals↗
PubMed1982

Purification, concentration and evaluation of rabies virus antigen.

A number of concentration and purification procedures for rabies virus antigen have been developed during the last decades but only ultrafiltration and density gradient centrifugation have been found suitable for large scale production. The antibody binding test developed by Arko, Wiktor and Sikes was modified and was found useful for evaluation of inactivated antigen-concentrates. This test was used as an 'in process' control. Three examples of practical experience are reported and discussed.

Animals↗
PubMed1982

Effects of intake of L-ascorbic acid on the incidence of dermal neoplasms induced in mice by ultraviolet light.

We have carried out a study of large malignant skin tumors (squamous cell carcinomas) and other lesions in hairless mice (groups of 38-45) intermittently exposed to ultraviolet light over a period of 15 weeks, beginning when the mice were about 10 weeks old. The several groups were given a standard diet with 0%, 0.3%, 5%, and 10% added L-ascorbic acid (vitamin C) throughout the study. No lesions developed in unirradiated control groups. The lesions were counted every 14 days for 4 months, beginning 4 weeks before the end of the period of irradiation. The observed incidence of lesions of several sizes during successive time periods was analyzed by the statistical method recommended by a committee of the International Agency for Research on Cancer. A pronounced effect of vitamin C in decreasing the incidence and delaying the onset of the malignant lesions was observed with high statistical significance.

Animals↗
PubMed1982

Blink reflexes elicited by electrical, acoustic and visual stimuli. I. Normal values and possible anatomical pathways.

Blink reflexes elicited by electrical stimulation of the supraorbital nerves, by monoaurally presented 1 kHz sine wave bursts of 20-ms duration, and by flashes of light presented monocularly were investigated in 32 healthy controls. Absolute latencies of the individual components and side differences were measured. An outline of possible anatomical pathways which might be involved in the transmission of these reflexes is given.

Acoustic Stimulation↗