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R Scholz

Publications and source records attributed to R Scholz.

At least 19 recordsLinked to original sources
PubMed1995

Recognition performance of subjects with color-vision deficiencies on a polychromatic sonar screen for ship navigation.

To facilitate differentiation between objects that are approaching, stationary, and moving away, these objects are represented in different colors on the screens of sonar locating devices used in ship navigation. Yellow represents stationary objects, and represents approaching objects, and green represents those objects moving away. A total of 46 subjects with normal color vision and 184 individuals with color-vision deficiencies, among them 29 deuteranopic, 100 deuteranomalous, 21 protanopic and 34 protanomalous individuals, were investigated for their ability to identify different signals. Ten different objects were presented for a period of 64 s each. As a minimal requirement it was established that 50% of the respective experimental group be capable of recognizing the objects within half of this time. Whereas 73.3% of the subjects with normal color vision could meet this requirement, none of the subjects in the different groups with color-vision deficiencies could do so. Only 16.1% of the deuteranopic subjects, 33.1% of the deuteranomalous individuals, 16.2% of the protanopic subjects, and 37.6% of the protanomalous individuals detected all objects within 32 s. No appreciable difference in the ability to recognize signals occurred among the different groups of subjects with color-vision deficiencies.

Color Perception↗
PubMed1994

Insulin-induced translocation of GLUT 4 in skeletal muscle of insulin-resistant Zucker rats.

The genetically obese Zucker rat (fa/fa) is an animal model with severe insulin resistance of the skeletal muscle. We investigated whether a defect of insulin-dependent glucose transporter (GLUT 4) translocation might contribute to the pathogenesis of the insulin-resistant state. fa/fa rats, lean controls (Fa/Fa) as well as normal Wistar rats were injected intraperitoneally with insulin and were killed after 2 or 20 min, respectively. Subcellular fractions were prepared from hind-limb skeletal muscle and were characterized by determination of marker-enzyme activities and immunoblotting applying antibodies against alpha 1 Na+/K+ ATPase. The relative amounts of GLUT 1 and GLUT 4 were determined in the fractions by immunoblotting with the respective antibodies. Insulin induced an approximately two-fold increase of GLUT 4 in a plasma membrane and transverse tubule enriched fraction and a decrease in the low density enriched membrane fraction in all three groups of rats. There was a high individual variation in GLUT 4 translocation efficiency within the groups. However, no statistically significant difference was noted between the groups. No effect of insulin was detectable on the distribution of GLUT 1 or alpha 1 Na+K+ ATPase. The data suggest that skeletal muscle insulin resistance of obese Zucker rats is not associated with a lack of GLUT 4 translocation.

Animals↗
PubMed1994

[Visual acuity of military personnel with civilian or military driver's license on consulting an ophthalmologist].

Visual acuity was tested in 1861 members of the German armed forces who possessed military or civilian driving licences, first by means of a screening test (Roden-stock R12) and second by an ophthalmologist observing German Industrial Standard 58220, part 3. The tests were done with the patients wearing any corrective spectacles in use before the appointment. In 27.6% of all subjects the monocular or binocular visual acuity was less than 1.0. Binocular visual acuity less than 1.0 was found in 17.0%, less than 0.8 in 7.3% and less than 0.5 in 0.9%. After adjustment of the corrective lenses by the ophthalmologist these figures were reduced to visual acuity less than 1.0 in 1.6%, less than 0.8 in 0.4% and less than 0.5 in 0.1%. The frequency of suboptimal visual acuity showed no difference in driving licence classes. We found fewer cases of suboptimal visual acuity in our patients than Kratz and Häseker found in the civilian community in the study published in 1986. The age distribution was also different. In contrast to former publications, which showed an age-related progression, our population had the lowest number of subjects with subnormal visual acuity in the age group 35-45 years. The screening test for visual acuity and the test by the ophthalmologist showed the same results in 76.8% of cases.

Adult↗
PubMed1994

Histology of tissue adjacent to an HAC-coated femoral prosthesis. A case report.

We studied the fixation of a cementless titanium femoral prosthesis partially coated with hydroxyapatite ceramic (HAC) 10.4 months after implantation. Histomorphological investigation showed extensive new bone formation between the HAC coating and the bone bed; morphometry showed bone contact indices of up to 91.60%. There were a number of resorption lacunae on the HAC coat with depths of up to 76.6 microns and widths of up to 453 microns. Our results confirmed that considerable bone remodelling had taken place and that the apatite-coated prosthesis had united with bone despite the lack of appreciable immediate press-fit. Hydroxyapatite particles which had been released did not appear to show any negative effects on the stability of the implant.

Aged↗
PubMed1992

Normal insulin receptor tyrosine kinase activity and glucose transporter (GLUT 4) levels in the skeletal muscle of hyperinsulinaemic hypertensive rats.

The spontaneous hypertensive rat is an animal model characterized by a syndrome of hypertension, insulin resistance and hyperinsulinaemia. To elucidate whether in analogy to other insulin resistant animal models an inactivity of the insulin receptor kinase or an alteration of the glucose transporter (GLUT 4) level in the skeletal muscle might contribute to the pathogenesis of insulin resistance we determined insulin receptor kinase activity and GLUT 4 level in the hindlimbs of spontaneous hypertensive rats and normotensive control rats. Normotensive normoinsulinaemic Lewis and Wistar rats were used as insulin sensitive controls, obese Zucker rats were used as an insulin resistant control with known reduced skeletal muscle insulin receptor kinase activity. Binding of 125I-insulin, crosslinking of 125I-B26-insulin, autophosphorylation in vitro with 32P-ATP and phosphorylation of the synthetic substrate Poly (Glu 4: Tyr 1) were performed after partial purification of solubilized receptors on wheat germ agglutinin columns. GLUT 4 levels were determined by Western blotting of subcellular muscle membranes. Insulin receptors from spontaneous hypertensive rats compared to those from Lewis and Wistar rats showed no difference of the binding characteristics or the in vitro auto- and substrate phosphorylation activity of the receptor, while in the Zucker rats the earlier described insulin receptor kinase defect was clearly evident. Western blots of subcellular muscle membrane fractions with antibodies against GLUT 4 revealed no difference in transporter levels. These data suggest that insulin resistance in spontaneous hypertensive rats is caused neither by an insulin receptor inactivity nor by a decreased number of glucose transporters in the skeletal muscle.

Adenosine Triphosphate↗
PubMed1992

Soluble CD8, CD25 and CD30 antigens as prognostic markers in patients with untreated Hodgkin's lymphoma.

In a search for serum markers with prognostic value and specificity for disease activity in Hodgkin's lymphoma, we evaluated the clinical significance of soluble suppressor/cytotoxic T-cell antigen (sCD8), soluble interleukin-2 receptor (sCD25) and soluble Hodgkin's associated antigen (sCD30) levels in the serum of 90 patients with untreated Hodgkin's lymphoma (HD). HD patients in advanced stages had significantly higher sCD8 and sCD25 levels than normal controls. The rate of detectable sCD30, which was absent in healthy controls, depended on stage and histological subtype, and was 22% for the entire group. Low sCD25 levels (< 1000 U/ml) predicted an excellent prognosis (100% event-free survival), while patients with high sCD8 levels (> 750 U/ml) or the demonstration of sCD30 had a poor outcome. Therefore, all three markers have prognostic significance. However, only sCD30 correlated strictly with disease activity and seems to be of value for the follow-up of patients in remission.

Adolescent↗
PubMed1992

Olsalazine-related diarrhoea: does rat intestine adapt in vivo?

Diarrhoea may occur in up to 10% of patients with ulcerative colitis treated with olsalazine, the azolinked dimer of 5-aminosalicylic acid. However, this symptom often disappears despite continued drug medication. To examine reversibility of and adaptation to olsalazine effects on intestinal absorption, rats were fed olsalazine (4 mg/100 g body weight/day) for 0 (controls), 12, 24, and 32 days. Jejunal, ileal, and colonic loops were perfused in situ with buffer or olsalazine (11.6 mM) in a pendular perfusion system. Water and electrolyte absorption was inhibited in all intestinal segments (p less than 0.001). In the proximal small intestine, however, sodium absorption was inhibited by 61%, whereas chloride and potassium absorptions were turned into net secretion. In contrast, in ileal and colonic segments sodium, chloride, and potassium absorptions were turned into a net secretion. All inhibitory effects were reversible within a short time. Intestinal absorption remained inhibitable compared with controls (p = not significant) after chronic administration of olsalazine even for 1 month. Jejunal monosaccharide absorption was not altered by acute olsalazine perfusion. In the ileum, glucose absorption was significantly inhibited, but the inhibitory capacity of acute olsalazine application decreased significantly (p less than 0.05) depending on duration of olsalazine pretreatment (51% (controls) versus 38% (32 days)). These results point to a complex, acute, but fully reversible effect of olsalazine on intestinal passive and chloride-coupled absorptive processes. Since a mucosal adaptation to these diarrheogenic effects does not occur, the resulting increase in fluid load on the diseased colon may be important in the pathogenesis of olsalazine-related diarrhoea.

Adaptation, Physiological↗
PubMed1992

The clinical significance of cytokines and soluble forms of membrane-derived activation antigens in the serum of patients with Hodgkin's disease.

In a search for specific serum markers with prognostic impact in Hodgkin's Disease (HD), we evaluated the clinical significance of several cytokines (IL-1 beta, IL-2, IL-3, IL-6, G-CSF, GM-CSF, TNF-alpha) and soluble forms of membrane-derived antigens (sCD4, sCD8, sCD23, sCD25, sCD30) in the serum of patients with untreated HD. Elevations of three groups of serum factors were observed: Firstly, elevations of the hematopoietic cytokines GM-CSF (detected in 39%), IL-6 (57%) and IL-3 (13%), which occurred simultaneously in the majority of the cases; secondly, simultaneous elevations of the inflammatory cytokines TNF-alpha and IL-1 beta (detected in 7%); and finally, elevations of membrane-derived activation antigens sCD8, sCD25, and sCD30. While the cytokine levels did not correlate with other obvious parameters, the membrane-derived activation antigens sCD8, sCD25 and sCD30 were associated with a poor prognosis. Only sCD30 correlated with disease activity and holds promise for the follow-up of patients in remission. Further investigations of these parameters at the cellular level might help to elucidate the enigmatic biology of HD.

Antigens, CD↗
PubMed1992

Increased levels of circulating cytokines in patients with untreated Hodgkin's disease.

Expression of several cytokines has been demonstrated in Hodgkin and Reed-Sternberg (H&RS) cells in vitro and in vivo. In order to determine whether interleukin-1 beta (IL-1 beta), IL-3, IL-6, GM-CSF, G-CSF, and TNF-alpha are elevated in Hodgkin's disease (HD), we tested the sera of untreated patients with HD by means of sensitive sandwich ELISAs. GM-CSF was detected in 22/56 patients (39%; range 40-140 pg/ml), IL-3 in 5/40 (13%; range 13-26 pg/ml), and IL-6 in 32/56 patients (57%; range 12-332 pg/ml). TNF-alpha and IL-1 beta were detected in only 3/43 patients (7%; range: TNF-alpha: 36-66 pg/ml; IL-1 beta: 389-1505 pg/ml) and G-CSF not at all. All patients with measurable IL-3 levels had both elevated IL-6 and GM-CSF levels, and the majority of patients with elevated IL-6 also had elevated GM-CSF levels and vice versa. In contrast, the 3/40 patients with both measurable IL-beta and TNF-alpha did not have elevated IL-3, IL-6, or GM-CSF levels. Cytokine levels were independent of stage or the presence of B-symptoms, and there was no correlation with any other clinical or laboratory parameter. Elevations of the respective cytokines might be a means to maintain normal blood cell counts in the respective patients with HD.

Adolescent↗
PubMed1991

[Mass screening of blue color vision in divers with the desaturated Lanthony-15-Hue Test].

We tested 1002 persons, 572 divers (including 38 who had diving accidents) and 430 nondivers, for defects of the blue-sensitive system during the years 1988 and 1989. Recent research has shown functional disorders of color vision in divers, linked to previously described alterations of the retinal capillary system and pigment epithelium. The desaturated Lanthony-15-HUE test was used as a screening method. No defect of the blue-sensitive system was found, either in divers or in nondivers. Our results are similar to those of other researchers. One exception was that we found no correlation between age and error score. We found no evidence for retinal damage caused by diving.

Adult↗
PubMed1991

[Intra- and extra-capsular condyle fractures in the growth period. Therapy, clinical course, complications].

37 patients had been reviewed after surgical (n = 25) or conservative (n = 12) treatment of condylar fractures. Morphologic and functional outcomes were equal in spite of the poorer starting position of the patients that had been operated on. Injuries and complications due to the operation, such as facial nerve palsy, growth inhibition or obvious scars have never been found. Conservatively treated and operated patients alike showed a moderate limitation of opening and mediotrusion on the fracture side, and both groups showed a flattening of the protrusion path.

Adolescent↗
PubMed1990

[Midfacial and mandibular fractures during the growth period].

This study investigated the occurrence of primary and secondary complications following conservative versus surgical intervention in the treatment of midface and lower jaw fractures. Follow-up studies were undertaken on 81 patients who had been admitted to the above clinic with such fractures during their adolescence. It was found that more complications developed after surgical intervention.

Adolescent↗
PubMed1988

Influence of disposable ('Conchapak') and reusable humidifying systems on the incidence of ventilation pneumonia.

The contamination of disposable ('Conchapak') and reusable humidifying systems and their influence on the incidence of pneumonia was studied in 116 patients requiring continuous mechanical ventilation therapy. The water reservoirs of 11 (15.9%) of the 69 disposable systems became colonized, but all reusable systems were found to be sterile. In four of the 11 samples, the organisms isolated corresponded with those cultured from tracheal secretions several days before. Ventilator-associated pneumonia occurred in 36 (31.0%) of the patients, but there was no statistically significant difference in the incidence of pneumonia between the patients treated with the disposable or the reusable humidifying systems. Gram-negative bacteria were the predominant organisms isolated from tracheal aspirates of patients who developed ventilator-associated pneumonia. These results suggest that disposable humidifying systems do not influence the rate of ventilator-associated pneumonia in mechanically ventilated patients.

Adult↗