Biomedical subjects

T Kremer

Publications and source records attributed to T Kremer.

5 recordsLinked to original sources

PubMed1997

The role of platelet-activating factor in conscious, normotensive endotoxemia.

The effects of endotoxin have been postulated to be mediated in large part by release of endogenous platelet-activating factor (PAF) due to the similarity of their hemodynamic and gastric effects in anesthetized animals, and to the ability of PAF inhibitors to ameliorate endotoxin's effects. We chose to examine the relationship with doses that would not produce circulatory shock, in unrestrained conscious animals, in order to mimic clinical situations. Adult male rats were prepared with vascular access, hemodynamic and temperature monitors, and gastric strain gauge transducers. After an overnight fast, rats received a 4-hr infusion of saline (0.5 ml/hr), endotoxin (12.5 mg/kg/hr), PAF (36 micrograms/kg/hr, or 600 ng/kg/min), or endotoxin plus the PAF inhibitor CV 3988 (1 mg/kg/hr, after an initial pretreatment of 1 mg/kg). Rats were killed, stomachs were harvested, and contents were analyzed at the end of the infusions. Blood pressure was not affected by any treatment, but all treated groups developed diarrhea and vasodilatation. Endotoxin and PAF infusions decreased heart rate and body temperature to a similar extent, although the PAF effect on temperature was delayed. The PAF inhibitor did not prevent the body temperature effect, but did reverse it. Gastric secretions were affected by PAF to a lesser extent than by endotoxin, and the PAF inhibitor did not decrease endotoxin's gastric secretory effects. PAF has similar systemic and gastric effects to endotoxin in conscious, unrestrained, normotensive animals. The systemic effects of endotoxin at 12.5 mg/kg/hr were prevented or reversed by the PAF inhibitor CV-3988 at 1 mg/kg/hr, but not the gastric secretory effects.

Animals↗

PubMed1997

[Disruption of the blood-aqueous barrier after implantation of sclera-fixed posterior chamber lenses. Early postoperative phase and long-term outcome].

The implantation of transsclerally sutured posterior chamber lenses (PCL) leads to greater trauma to the eye than endocapsular PCL implantation. Persistent breakdown of the blood-aqueous barrier might impair the postoperative long-term prognosis. Using laser-tyndallometry, we quantified the disorder of the barrier function during the early postoperative phase and in the long-term postoperative course for both surgical procedures. During the first 3 postoperative days, flare values were three times higher in the group with transsclerally sutured PCL than in the conventional PCL group. Cell counts after transscleral suture fixation (27.7 +/- 18.3/0.075 mm3) decreased slightly during the first 5 postoperative days. In contrast, the conventional PCL group regained the preoperative level (2.5 +/- 5.1) after 3 days. After 3 months, no significant differences in flare values and cell counts were seen between the two groups. After implantation of transsclerally sutured posterior chamber lenses, breakdown of the blood-aqueous barrier was initially more pronounced than in conventional PCL implantation. However, the barrier function was re-established equally in both groups in the long term. No signs of a persistent disorder of the barrier were found.

Adult↗

PubMed1997

Research validity scales for the NEO-PI-R: development and initial validation.

The purpose of this investigation was to develop a set of research validity scales for use with the NEO Personality Inventory-Revised (NEO-PI-R; Costa & McCrae, 1992b). In study 1 we used the existing NEO-PI-R item pool to select items for three validity scales: positive presentation management, negative presentation management, and inconsistency. Several iterative item and scale analyses were conducted, using multiple criteria for item selection. These analyses resulted in 10-item scales. In Study 2, the internal consistency, interscale relationships, and normative characteristics were examined in a separate sample of working adults. In Study 3, the validity of the scales was examined by contrasting five sets of NEO-PI-R protocols: from a separate sample of working adults, from a sample of 100 NEO-PI-R protocols with randomly produced responses, and from three samples of undergraduates completing the NEO-PI-R under different instructional sets. Analyses revealed that both the research validity scales and the NEO-PI-R domain scales were sensitive to group differences. issues relating to the appropriate use of the scales are discussed.

Journal Article↗

PubMed1996

Deuteranomaly studied with four perceptual criteria.

In the theoretical section of the present paper, we develop our view of the roles played by the perceptual criteria: indistinguishably equal, neither blue nor yellow, neither green nor red, and heterochromatically equally bright. These criteria constitute a vectorial opponent-colour space, a concept used throughout the paper. Within this framework, two new theorems on psychophysical opponent-colour channels are stated. In the experimental section, the perceptual criteria are applied to the colour vision of an (extreme) deuteranomalous male. A quantitative perceptual description of his deuteranomaly is developed, the main constituents of which are measured deuteranomalous colour matching functions, the deuteranomalous opponent-colour functions derived from them and taking quantitative account of the Abney effect.

Color Perception Tests↗

PubMed1983

Identification of a human pancreatic duct tissue-specific antigen.

Antiserum raised against a pancreatic duct mucin was absorbed with type AB red blood cells and used in the indirect immuno-glucose oxidase procedure to examine tissue specificity. All mucin-producing organs were stained by this antiserum. Absorption of the antiserum with mucinous ovarian cystadenocarcinoma fluid eliminated generalized mucin staining, and only pancreatic ducts and colonic goblet cells were positive. Further absorption with purified colonic mucin revealed a pancreatic duct tissue-specific determinant(s). This tissue-specific determinant(s) was detected in the RIP-1 and RIP-2 human pancreatic adenocarcinomas carried as xenografts in athymic nude mice. Because the majority of pancreatic adenocarcinomas are believed to arise from ductal tissue, pancreatic duct mucin may have a useful role as a marker in detection and differential diagnosis.

Animals↗