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Biomedical subjects

R Pace

Publications and source records attributed to R Pace.

50 records · Page 3Linked to original sources
PubMed1982

Phoria measurements using chromatic targets.

Von Graefe phoria measurements were obtained for ten prepresbyopic subjects at 40 cm and 6 m test distances using a vertical column of black letters on red, green, and white backgrounds. Phorias measured at 40 cm using red and white target backgrounds were similar, but the phoria measured using a green target background indicated a change toward greater exophoria. No difference in phoria measurements was found between all targets at 6 m.

Accommodation, Ocular↗
PubMed1982

Microcirculation of left atrial muscle, cerebral cortex and mesentery of the cat. A comparative analysis.

By means of transillumination (microtransilluminator and light pipe), comparative analyses were carried out on geometry, topography, and morphometry of microcirculation in the cerebral cortex, left atrial muscle, and mesentery of the cat using computer analysis. In addition, specific types of capillary distribution (concurrent, countercurrent, and asymmetric distribution) in these three organs were ascertained from images visualized on films. These parameters were related to their role in tissue oxygen supply. It was found that mean capillary diameter, mean intercapillary distance, total capillary length, and total capillary surface area differed significantly among the three organs. Differences in mean capillary tortuosity between cerebral and left atrial muscle and between left atrial muscle and mesentery also were significant. Mean capillary tortuosity in mesentery and cerebral cortex was of equal magnitude. In the cerebral cortex, a high degree of tortuosity and asymmetric capillary distribution favor tissue oxygenation. A similar situation exists in left atrial muscle, although some concurrent and countercurrent distribution could be detected. In the mesentery, the combination of high capillary tortuosity and concurrent capillary arrangement is unfavorable for tissue oxygenation.

Animals↗
PubMed1981

Defective suppressor cell activity in cancer patients: a defect in immune regulation.

Although suppressor cells appear to be involved in the normal regulatory mechanism of the lymphoid system, they are also considered to have a role in the immunosuppression of certain malignancies. Suppressor activity of lymphocytes can be reproducibly measured by use of the mixed lymphocyte culture-mitogen interaction (MLC-M) in which the stimulating cell either is in the basal state or has been induced by Concanavalin A. This yields a quantitative measure of resting suppressor cell activity as well as the maximum generation of suppressor activity as induced by Con A. This test was performed, using autologous and allogenic cell combinations in a group of 13 cancer patients and 18 normal controls. Normal lymphocytes activated by Con A in 48-hour lymphocyte cultures significantly decreased the mitogenic response of lymphocytes from healthy, male donors to phytohemagglutinin (PHA), Con A, and Pokeweed mitogen (PWM) in both autologous and homologous systems. In contrast, Con A activated lymphocytes from cancer patients demonstrated diminished suppressor activity compared with controls in autologous (P less than 0.01), and allogenic (P less than 0.005) systems. There was a correlation between the degree of immunosuppression and suppressor cell activation: i.e., the patients most depressed generally had the lowest suppressor cell activation. Untreated lymphocytes from cancer patients also exerted suppressive effects on normal lymphocyte responses, suggesting an increased resting level of suppressor cells. These data suggest that in addition to having depressed cellular immune responses, cancer patients frequently have reduced capability to generate suppressor cell activity, which implies a generalized defect in this aspect of immune regulation.

Adult↗
PubMed1981

Protein quality and the cost of selected commercial protein supplements.

The biologic value and the cost of three commercial protein supplements were compared using casein as the control. Each product was fed to rats as the sole protein source supplying 10 percent of the energy in a semipurified diet. Nonfat dry milk was equal to casein in PER, but the PERs of low-fat soy powder and high-protein supplement were significantly lower than the PER of casein. Nitrogen balance was positive for all protein supplements, but low-fat soy powder was significantly lower than the others. cost comparison per gram of protein showed low-fat soy powder to be the least expensive, nonfat dry milk to be slightly higher in cost, and the high-protein supplement to be the most expensive.

Animals↗
PubMedDate not supplied

Detachable balloon occlusion of bronchopleural fistulae in dogs.

The use of detachable balloon occlusion in closure of bronchopleural fistulae was investigated in eight dogs. Fistula occlusion could not be achieved in one dog, and the balloon was not large enough to occlude a fistula in a second dog. Satisfactory fistula occlusion was achieved in the remaining six dogs. All fistulae occluded were shown to be satisfactorily healed at ten days. There were no significant sequelae to bronchial occlusion during this period. Detachable balloon occlusion of bronchopleural fistulae has the potential for satisfactory fistula control prior to more definitive surgery.

Animals↗
PubMedDate not supplied

Determination of ginsenosides in Panax ginseng roots by liquid chromatography with evaporative light-scattering detection.

A liquid chromatographic method was developed and validated for the determination of ginsenosides in Panax ginseng roots by using evaporative light-scattering detection. Eighteen ginsenosides were separated on a reversed-phase C18 column with water-ammonium acetate-acetonitrile as the mobile phase. The method is suitable for the routine determination of ginsenosides in P. ginseng roots and extracts. The validation of the method was comprehensive for efficiency and recovery optimization of the P. ginseng roots extraction, specificity by liquid chromatography/mass spectrometry, linearity, stability, reproducibility, repeatability, intermediate precision, and robustness.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

[Periodontic-endodontic lesions: diagnostic and therapeutic indications].

The presence of connections between periodontium and endodontium can lead to the diffusion of an infection from one apparatus to another. The involvement of both periodontium and endodontium is defined as Combined Periodontic-Endodontic lesions. This definition is not based on the initial etiology of the lesion and either the endodontic or periodontal lesion may be the cause or the result of the other or both may develop independently. The lesions must be correctly diagnosed for the best therapeutic approach. The diagnosis is based on clinical symptoms and radiographic analysis; clinical signs must show the presence of periodontal probing and pulpal necrosis. Radiographic examination can confirm the involvement of both periodontium and endodontium only if the lesion is present on the mesial and distal part of the diseased tooth; in the case of a palatal/lingual or vestibular lesion such evidence will not be detectable. The therapeutic approach is always based on an initial endodontic treatment followed, if needed, by the proper periodontal treatment.

Dental Pulp Diseases↗
PubMedDate not supplied

[The lamina limitans. Its scanning electron microscopic aspects].

Many researches agree in maintaining that all the membraneous structure visible in the most external parts of the dental tubules must be considered not ad cytoplasmatic membranes of the odontoblastic processes but as an extracellular organic matrix which in certain conditions may appear detached from the internal wall of the tubule and simulated a superimposable aspect like that of an odontoblastic extension. The aim of this study was to examine at the SEM the state of this organic component in normal conditions and after demineralization with citric acid. Therefore the entire teeth of young people were fixed in formalin and dissected by fracturing. Some of the samples were demineralized with a citric acid solution. All the samples were dehydrated and metallized for the observation at SEM. Demineralization made the peritubular dentine disappear and expose inside every tubule a sheet-like structure which extended all along the tubules. The samples which were not demineralized did not demonstrate a similar structure because of their tight adhesion to the internal wall surface. This kind of formation which other researchers calls "lamina limitans" because of its high content of glycosaminoglycans might be a key factor in controlling the formation of peritubular dentine and tubular sclerosis and it will surely lead to further interesting research.

Decalcification Technique↗