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Biomedical subjects

B Bauer

Publications and source records attributed to B Bauer.

At least 19 recordsLinked to original sources
PubMed1997

Extracellular glutathione peroxidase and ascorbic acid in aqueous humor and serum of patients operated on for cataract.

Patients operated on for cataract (32 men/75 women, aged 50-93 years) were studied with respect to antioxidative agents in aqueous humor and serum. Extracellular glutathione peroxidase (eGSHPx) was demonstrated in aqueous humor for the first time by a radioimmunoassay, the concentration of eGSHPx being 0.66(0.18) mg/l (mean(S.D.)). The concentration of eGSHPx in serum was 3.81(0.84) mg/l, and its level in aqueous humor was 18(7)% of that level. Serum selenium had positive correlations with both serum eGSHPx (r = 0.34, P < 0.001) and aqueous humor eGSHPx (r = 0.25, P = 0.011). However, there was no relation between the concentrations of eGSHPx in aqueous humor and in serum, suggesting that the maintenance of eGSHPx levels in the two fluids is controlled by different mechanisms beside selenium status. There was an inverse correlation between age and serum eGSHPx but not with aqueous humor eGSHPx. The concentration of ascorbic acid in aqueous humor was 2.04(0.58) mmol/l, and it was closely correlated to the level of ascorbic acid in serum (0.052(0.032) mmol/l), r = 0.58 (P < 0.001). The ratio between the level of ascorbic acid in aqueous humor and that in serum was 39(17). There was no significant difference among patients with nuclear (n = 39), cortical (n = 20), posterior-subcapsular (n = 23) or mixed (n = 23) lens opacity with respect to levels of eGSHPx and ascorbic acid in serum and aqueous humor. Since serum ascorbic acid is related to ascorbic acid intake, its association to aqueous humor ascorbic acid indicates that dietary habits are important for maintaining that level which could play an important role in protecting ocular tissue against oxidative damage. The role of eGSHPx secreted into aqueous humor in the oxidant defence system needs further study.

Aged↗
PubMed1997

[Physicians' attitude in the treatment of incompetent patients. Comparison between East and West Germany].

BACKGROUND: Health care decision-making in incompetent severely ill patients presents a number of difficult medical, ethical and legal problems for the physician. The factors and the degree to which various factors contribute to such decisions have rarely been investigated. SUBJECTS AND METHODS: 310 physicians from the state of Baden-Württernberg (Western Germany) and the state of Mecklenburg (eastern Germany) were asked by means of a questionnaire to rate the importance of eight factors in their health care decisions in the elderly. RESULTS: Both, ethical concerns and patients' wishes emerged as the most important factors for decisions in both subsamples. However, significant differences in the degree to which the factors hospital costs, patients' and family wishes, the level of dementia and the patients' age contribute to their decisions could be found between the answers of the doctors of the two lands. CONCLUSIONS: The socialization of the physicians in different health care and social systems seems to be one of the most important reasons for different health care decisions in old and incompetent patients.

Adult↗
PubMed1997

Conventional PKC-alpha, novel PKC-epsilon and PKC-theta, but not atypical PKC-lambda are MARCKS kinases in intact NIH 3T3 fibroblasts.

Phosphorylation of myristoylated alanine-rich protein kinase C substrate (MARCKS) in intact cells has been employed as an indicator for activation of protein kinase C (PKC). Specific PKC isoenzymes responsible for MARCKS phosphorylation under physiological conditions, however, remained to be identified. In our present study using stably transfected NIH 3T3 cell clones we demonstrate that expression of constitutively active mutants of either conventional cPKC-alpha or novel nPKC-epsilon increased phosphorylation of endogenous MARCKS in the absence of phorbol 12,13-dibutyrate in intact mouse fibroblasts, implicating that each of these PKC isoforms itself is sufficient to induce enhanced MARCKS phosphorylation. Similarly, ectopic expression of a constitutively active mutant of PKC-theta significantly increased MARCKS phosphorylation compared to vector controls, identifying PKC-theta as a MARCKS kinase. The PKC-specific inhibitor GF 109203X (bisindolylmaleimide I) reduced MARCKS phosphorylation in intact cells at a similar dose-response as enzymatic activity of recombinant isoenzymes cPKC-alpha, nPKC-epsilon, and nPKC-theta in vitro. Consistently, phorbol 12,13-dibutyrate-dependent MARCKS phosphorylation was significantly reduced in cell lines expressing dominant negative mutants of either PKC-alpha K368R or (dominant negative) PKC-epsilon K436R. The fact, that the constitutively active PKC-lambda A119E mutant did not alter the MARCKS phosphorylation underscores the assumption that atypical PKC isoforms are not involved in this process. We conclude that under physiological conditions, conventional cPKC-alpha and novel nPKC-epsilon, but not atypical aPKC-lambda are responsible for MARCKS phosphorylation in intact NIH 3T3 fibroblasts.

3T3 Cells↗
PubMed1997

Effective doses to members of the public from the diagnostic application of ionizing radiation in Germany.

The exposure of the German population to man-made radiation results mainly from diagnostic X-ray and nuclear medical examinations. Data are presented about the annual frequency and the average dose of the various examination types for West Germany in the years 1990-1992. According to these data a yearly average of approximately 1550 diagnostic examinations using ionizing radiation were performed per 1000 inhabitants resulting in an annual per caput effective dose of 1.9 mSv. Despite the frequent use of alternative examination techniques, such as sonography, nuclear magnetic resonance and endoscopy, the frequency of X-ray and nuclear medical examinations is still increasing. If collective risk assessments are done using the per caput effective dose, at least the age distribution of the patients must be considered. This leads to a "risk-modifying factor" of 0.6-0.7 for patients to be applied to the ICRP risk coefficient of 5 % per Sv valid for the general population. However, radiation risk must always be viewed in context with disease- and therapy-related risks and balanced against the benefit of the diagnostic examination, which should always exceed the risk for a well-indicated procedure.

Adolescent↗
PubMed1997

The effect of Wilms tumor chemotherapy on contralateral renal growth after nephrectomy.

PURPOSE: Our aim was to evaluate the effect of current Wilms tumor chemotherapy on renal growth and function after unilateral nephrectomy. MATERIALS AND METHODS: Yorkshire piglets were enrolled in 2 study groups: group 1--6 underwent unilateral nephrectomy and placebo infusion, and group 2--10 underwent nephrectomy, and infusion of 7.5 mcg/kg. actinomycin D and 0.75 mcg/m2 vincristine according to the National Wilms Tumor Study 4 protocol. Weekly measurements of renal size by ultrasound and gross specimens at sacrifice at age 11 weeks were examined and weekly laboratory studies were recorded. Growth rates of renal length and volume were evaluated by linear regression analysis. Terminal renal length and volume were compared between groups. RESULTS: Mean slope plus or minus standard deviation of the rate of growth in length in the control and chemotherapy groups was 0.067 +/- 0.004 and 0.074 +/- 0.011, respectively (p < or = 0.148, not statistically significant). Mean slope of growth in volume was 1.401 +/- 0.240 versus 1.642 +/- 0.456 (p < or = 0.252), average terminal renal length was 10.71 +/- 1.02 versus 11.58 +/- 1.03 cm (p < or = 0.13, not significant) and mean final volume was 128.67 +/- 32.41 versus 137 +/- 32.52 cc (p < or = 0.65). No differences in final serum creatinine levels were noted. CONCLUSIONS: Chemotherapy for Wilms tumor did not adversely affect contralateral renal growth or function in a nephrectomized piglet model.

Animals↗
PubMed1997

Cognitive processing in primary headache: a study on event-related potentials.

BACKGROUND: There is experimental evidence for loss of cognitive habituation in migraine but not in other types of headache and not by visual event-related potentials (ERP). OBJECTIVE: Determining the latencies (msec) and amplitudes (microV) of ERP components and the differences of these values in a two-trial analysis representing the amount of cognitive habituation. PARTICIPANTS: Two hundred thirty-three patients with a headache diagnosis according to the criteria of the International Headache Society: migraine without aura (N = 77); migraine with aura (N = 31); cluster headache during period (N = 26); cluster headache during interval (N = 11); chronic paroxysmal hemicrania (N = 8); episodic tension-type headache (N = 33); ergotamine-induced headache (N = 47). Thirty age-matched healthy subjects served as a control group. METHODS: ERPs were evoked by a visual oddball paradigm consisting of 2 x 200 flashes of light (85% white light; 15% red light). Evaluation of ERP components was done separately for the first 200 and the second 200 stimuli as well as for the entire series of stimuli. RESULTS: We found an acceleration of the P3 latency during the second trial in migraine with and without aura, but not in the other headache types, and not in healthy controls. Ergotamine and sumatriptan abolished this loss of habituation in migraine patients. Increased ERP latencies as compared with healthy controls were present in patients with cluster headache, tension-type headache, ergotamine-induced headache, and migraine with aura, but not in migraine without aura. CONCLUSION: There is a loss of cognitive habituation in migraine, which may serve as a specific but not sensitive diagnostic tool. The pathophysiologies of migraine and cluster headache have a specific modifying property on cognitive processing reflected by a loss of cognitive habituation or an increased cognitive processing time. These effects can, in part, be counterbalanced by antimigraine medication.

Adolescent↗
PubMed1997

Symptomatic hemangiomas and venous malformations in infants, children, and young adults: treatment with percutaneous injection of sodium tetradecyl sulfate.

OBJECTIVE: The purpose of this study was to evaluate the efficacy and safety of percutaneous sclerosis therapy using sodium tetradecyl sulfate for treatment of symptomatic hemangiomas and venous malformations in infants, children, and young adults. MATERIALS AND METHODS: Fifty-two sclerosis procedures were performed in 21 patients who were 13 months to 24 years old. Six of these patients had hemangiomas, and the remaining 15 patients had venous malformations. Sodium tetradecyl sulfate was injected solely percutaneously in 49 procedures, by both percutaneous and arterial routes in two procedures, and intraarterially only in one procedure. Thirteen patients had sclerosis therapy alone, and eight patients had sclerosis therapy followed by surgery within 48 hr. RESULTS: Sclerosis therapy alone or sclerosis therapy followed by surgery was judged beneficial in 18 (86%) of 21 patients, including five of the six patients who had hemangiomas and 13 of the 15 patients who had venous malformations. Two patients had an equivocal response to the therapy, and one patient had no apparent benefit. Three of the 21 patients had minor complications (skin ulcers) but no long-term sequelae. CONCLUSION: Percutaneous injection of sodium tetradecyl sulfate, either alone or before surgery, is a safe and effective method of managing symptomatic hemangiomas and venous malformations.

Adolescent↗
PubMed1996

RalGDS-like factor (Rlf) is a novel Ras and Rap 1A-associating protein.

The small GTPase Rap 1A is a close relative of Ras that, when overexpressed, is able to revert oncogenic transformation induced by active Ras. We screened a mouse embryonic cDNA library using the yeast two-hybrid system and isolated the cDNA of a novel Rap 1A-interacting protein. The open reading frame encodes for an 84 kDa protein with a Cdc25-homology domain which shares approximately 30% identity with Ral guanine nucleotide dissociation stimulator (RalGDS) and RalGDS-like (Rg1). The C-terminal region reveals a striking conservation of sequences with the Ras-binding domain of RalGDS. We designated this protein Rlf, for RalGDS-like factor. In the yeast system, Rlf interacts with Rap 1A, H-Ras and R-Ras, but not with Rac and Rho. In addition, we found that Rlf interacts with Rap 1Aval12 but not with Rap 1AAsn17. In vitro binding studies revealed that a C-terminally located 91 amino acid region of Rlf is sufficient for direct association with the GTP-bound form of Ras and Rap 1A. The observed dissociation constants are 0.6 microM and 0.4 microM, respectively. No significant association with Ras-GDP or Rap 1A-GDP could be detected. These binding characteristics indicate that Rlf is a putative effector for Ras and Rap 1A.

Amino Acid Sequence↗
PubMed1996

Cataract patients in a defined Swedish population, 1986 to 1990. V. Postoperative retinal detachments.

OBJECTIVE: To estimate the risk of retinal detachment after cataract surgery. DESIGN: Prospective study from December 17, 1985, through December 31, 1992 of all cataract surgeries performed in a single referral region of the Lund (Sweden) Health Care District from December 17, 1985, through December 31, 1990. SETTING: The University Hospital of Lund. PATIENTS: Data were collected on 5878 consecutive cataract operations. The study population was complete enough to represent all cataract surgery in the referral region during this period. RESULTS: Two years after cataract surgery, the risk of retinal detachment was 0.18%. The follow-up period after cataract surgery in this study was up to 7 years, with a mean of 50.7 months (>4 years), and the total risk of retinal detachment or detachment-related conditions was 0.71%, all cases included. The relative risk of detachment was 4.9 after YAG laser capsulotomy. It changed by a factor of 1.3 with an increase in the axial length of 1 mm and by 0.94 for each added year of patient age. CONCLUSION: A young patient with axial myopia operated on because of cataract and postoperatively treated with YAG laser capsulotomy runs an important increased risk of developing retinal detachment.

Adolescent↗
PubMed1996

Glucose consumption and methionine uptake in low-grade gliomas after iodine-125 brachytherapy.

We investigated whether 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) and carbon-11 methionine are suitable tracers to monitor the effects of therapy for low-grade gliomas. Ten patients with low-grade glioma without previous treatment were studied with FDG positron emission tomography. Additionally, l-[methyl-11C]methionine uptake was measured in five subjects before and 1 year after computerized tomography (CT)-guided stereotactic and computer-assisted implantation of iodine-125 seeds. All scans were 3D-matched to CT, isodose volumes were determined, and changes in glucose metabolism and methionine uptake were evaluated in tumour and brain tissue as a function of radiation dose. After 1 year glucose metabolism was not significantly altered up to a radiation dose of 300 Gy, whereas methionine uptake showed a significant dose-dependent decrease. Higher rates of decline were found in tumours with high basal methionine incorporation activity before therapy. These data suggest that measurement of methionine uptake is more suitable than measurement of FDG uptake for monitoring therapeutic effects in low-grade gliomas.

Adult↗
PubMed1996

Visual search for colour targets that are or are not linearly separable from distractors.

D'Zmura [(1991) Vision Research, 31, 951-966] reported qualitative differences in visual search rates for a target colour in a background of differently coloured distractors depending on their colour configuration in CIE(x,y) space. A target colour that was chromatically mid-way between the distractor colours resulted in steep search slopes. A target off the distractor-distractor line, "popped out". We replicated his finding in several loci, investigated several potential confounds, and discovered boundary conditions for the phenomenon: for a given target, the effect of collinearity dissipates with increasing distractor-distractor colour difference. Furthermore, within limits, performance was dependent on the target to distractor-line distance.

Adult↗
PubMed1996

Stimulus dimensionality effects in mental rotation.

Do 3-dimensional (3-D) figures require more time to rotate mentally than do 2-dimensional (2-D) figures? This question was examined in 2 experiments incorporating 15 2-D and 15 3-D stimuli. For 3-D stimuli, block figures were used of the type used by R. N. Shepard and J. Metzler in their classic studies. For 2-D stimuli, block figures were also used, but with all cubes in a single plane, resulting in 2-D and 3-D figures matched on surface features. Three-D figures elicited steeper slopes than did 2-D figures, supporting the view that the mental rotation of visual representations is sensitive to stimulus dimensionality. The authors summarize the results of several mental rotation studies that investigated stimulus dimensionality and suggest that the evidence across studies is consistent with the present finding. They discuss 2 plausible loci for the dimensionality effect in S. M. Kosslyn's (1980) theory of mental imagery.

Adolescent↗
PubMed1996

Protein kinase C-theta isoenzyme selective stimulation of the transcription factor complex AP-1 in T lymphocytes.

T-lymphocyte stimulation requires activation of several protein kinases, including the major phorbol ester receptor protein kinase C (PKC), ultimately leading to induction of lymphokines, such as interleukin-2 (IL-2). The revelant PKC isoforms which are involved in the activation cascades of nuclear transcription factors involved in IL-2 production have not yet been clearly defined. We have examined the potential role of two representative PKC isoforms in the induction of the IL-2 gene, i.e., PKC-alpha and PKC-theta, the latter being expressed predominantly in hematopoietic cell lines, particularly T cells. Similar to that of PKC-alpha, PKC-theta overexpression in murine EL4 thymoma cells caused a significant increase in phorbol 12-myristate 13-acetate (PMA)-induced transcriptional activation of full-length IL-2-chloramphenicol acetyltransferase (CAT) and NF-AT-CAT but not of NF-IL2A-CAT or NF-kappaB promoter-CAT reporter gene constructs. Importantly, the critical AP-1 enhancer element was differentially modulated by these two distinct PKC isoenzymes, since only PKC-theta but not PKC-alpha overexpression resulted in an approximately 2.8-fold increase in AP-1-collagenase promoter CAT expression in comparison with the vector control. Deletion of the AP-1 enhancer site in the collagenase promoter rendered it unresponsive to PKC-theta. Expression of a constitutively active mutant PKC-theta A148E (but not PKC-alpha A25E) was sufficient to induce activation of AP-1 transcription factor complex in the absence of PMA stimulation. Conversely, a catalytically inactive PKC-theta K409R (but not PKC-alpha K368R) mutant abrogated endogenous PMA-mediated activation of AP-1 transcriptional complex. Dominant negative mutant Ha-RasS17N completely inhibited the PKC-O A148E-induced signal, PKC-O. Expression of a constitutively active mutant PKC-O A148E (but not PKC-alpha A25E) was sufficient to induce activation of AP-1 transcription factor complex in the absence of PMA stimulation. Conversely, a catalytically inactive PKC-O K409R (but not PKC-alpha K368R) mutant abrogated endogenous PMA-mediated activation of AP-1 transcriptional complex. Dominant negative mutant Ha-enRasS17N completely inhibited in the PKC-O A148E-induced signal, identifying PKC-theta as a specific constituent upstream of or parallel to Ras in the signaling cascade leading to AP transcriptional activation.

Animals↗
PubMed1996

Activated protein C resistance in young adults with central retinal vein occlusion.

BACKGROUND: Central retinal vein occlusion is a disease that is most common in old people. While the disease in old people often is associated with atherosclerosis, hypertension, diabetes, or glaucoma, this is much less evident in young people. However, a new defect in the anticoagulant system has recently been discovered, activated protein C resistance. This hereditary defect may well be associated with central retinal vein occlusion, and so this factor was analysed in patients younger than 50 years with a history of central retinal vein occlusion. METHODS: Blood samples were obtained from 31 patients younger than 50 years with a history of central retinal vein occlusion, and analysed for activated protein C resistance with standard clinical laboratory methods. RESULTS: In this material 26% of all the patients and 36% of the patients younger than 45 years were resistant to activated protein C. The normal incidence of activated protein C resistance is 2-7%. CONCLUSION: Activated protein C resistance seems to be the most common known cause of central retinal vein occlusion in young people.

Adult↗
PubMed1996

Ramipril and felodipine: a comparison of the efficacy and safety of monotherapy versus combination therapy.

A multinational, double-blind, randomised study was conducted to investigate the efficacy and safety of a low-dose combination of the angiotensin converting enzyme inhibitor, ramipril, and the calcium antagonist, felodipine ER, in 642 patients with mild to moderate hypertension [supine diastolic blood pressure (DBP) = 95-115 mm Hg]. After a 4-week single-blind placebo run-in, patients were randomly allocated to once-daily felodipine extended release (ER; 2.5 mg), ramipril (2.5 mg) or felodipine ER/ramipril (2.5/2.5 mg) for 12 weeks. In the intention-to-treat analysis, mean DBP decreased significantly (p < 0.0001) after felodipine ER, ramipril and the combination (-9.1, -9.8 and -11.4 mm Hg, respectively). The decrease was significantly greater with the combination than with felodipine ER monotherapy (p = 0.02). The number of responding patients (final DBP < or = 90 mm Hg or a decrease of > or = 10 mm Hg) was also higher with the combination than with felodipine ER or ramipril monotherapy (65.1%, 53.1%, 55.7%, respectively). There were no differences between the three groups with respect to the incidence of adverse events overall or those considered treatment-related. There were fewer cases of peripheral oedema with combination therapy than with felodipine ER monotherapy. Thirty-three patients (5.1%) withdrew from the study because of adverse events, but there was no clear pattern with regard to the specific events leading to withdrawal. There were no clinically relevant changes in laboratory or clinical safety variables. Ramipril/felodipine ER 2.5/2.5 mg is an appropriate starting dosage when initiating combination antihypertensive therapy.

Adult↗