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Biomedical subjects

S Wolter

Publications and source records attributed to S Wolter.

At least 19 recordsLinked to original sources
PubMed2005

Presence of 14Hz spindle oscillations in the human EEG during deep anesthesia.

OBJECTIVE: To report on presence of human EEG spindle oscillations on the cortical level within flat periods of the burst-suppression pattern during propofol-induced anesthesia; to search for corresponding oscillations and possible functional connections. METHODS: Artefact-free epochs of spindle activation were selected from the electroencephalograms of opiate-dependent patients undergoing rapid opiate detoxification. Power spectral analysis and source localization using low-resolution-brain-electromagnetic-tomography (LORETA(Key)) were performed. RESULTS: Sinusoidal rhythms with waxing and waning amplitudes appeared after propofol-induced narcosis but no direct correlations could be determined between individual dosage and characteristic spindle attributes. The power maximum stood midline over the cortical areas, especially around C(z). We calculated a peak frequency of 14(+/-1.2) Hz. Motor fields, particularly in the frontal, parietal, and various cingulate areas, were found to be the primary sources of spindle oscillations in the cortex. CONCLUSIONS: The frequent occurrence of these localized spindle sources demonstrates the preference for motor fields. Spindle oscillations observed during propofol-induced narcosis were similar in frequency and shape to those observed in natural sleep. SIGNIFICANCE: The results lend support to models that postulate a close link between the motor system and the organization of behavior. In addition, spindle rhythms under propofol bore some resemblance to spindle types which occur during sleep.

Adult↗
PubMed2005

Post-training quality of syndromic management of sexually transmitted infections by chemists and druggists in Pokhara, Nepal: is it satisfactory?

OBJECTIVE: Using simulated client and provider interview methods, this study assessed chemists and druggists' post-training management quality of syndromic sexually transmitted infections focusing on the areas of privacy maintaining, encouraging, history taking, counseling, referral practice, partner notification, and drug prescribing and then compared the findings of two methods. DESIGN: Forty-five pharmacies from a list of 75 in Pokhara, who collected sexually transmitted infections data during 1999, were selected randomly. First simulated client successfully presented either urethral or vaginal discharge syndrome at 37 pharmacies and recorded the events of whole encounter into an observation form within 20 minutes. Later 39 chemists and druggists were interviewed by a pre-tested semi-structured questionnaire. MAIN MEASURE: Results were reported mainly by numbers and corresponding percentages. For comparative purpose, P values were also shown. RESULTS: Overall, interview method revealed satisfactory knowledge of chemists and druggists for management of sexually transmitted infections except drug prescribing but their actual behaviors, revealed by simulated client method, indicated lower quality and differed significantly in the areas of encouraging, history taking, counseling, referral practice, and partner notification. Both methods indicated very poor qualities of drug prescribing. CONCLUSION: Retained knowledge of chemists and druggists for syndromic management of sexually transmitted infections were not applied to simulated client in actual practice. They should not prescribe drugs for patients of sexually transmitted infections, except referring to the doctors/hospitals. Continuous monitoring and further motivations for them may improve syndromic management quality of sexually transmitted infections. Moreover, depending on the purpose of study, various methods should be applied simultaneously to reach a better conclusion.

Adult↗
PubMed2005

Comparative prospective study on splint therapy of anterior disc displacement without reduction.

A prospective randomized study was carried out to compare the therapeutic success of two different types of splint in patients with painful anterior disc displacement of the temporomandibular joint. The patients in Group I (n = 20) received stabilization splint therapy and the patients in Group II (n = 20) pivot splint therapy. Clinical investigation of the craniomandibular system was performed before and 1, 2 and 3 months after therapy and this was accompanied by subjective evaluation by the patients of their symptoms, using a validated questionnaire with visual analogue scales (VAS). There was a significant increase in maximum jaw opening and a significant reduction in subjective pain in both groups during the course of therapy (Wilcoxon test, P < 0.05). Active jaw opening increased by a mean of 8.05 mm in the group of patients treated with a stabilization splint (Group I). The comparable figure with pivot splint therapy (Group II) was 8.26 mm. The VAS scale value in Group I was reduced by 30.54 units and in Group II by 39.36 scale units. However, neither of these differences between the groups was statistically significant (Mann-WhitneyU-test, P > 0.05). It can be concluded that both types of splint provided effective therapy in patients with anterior disc displacement.

Adolescent↗
PubMed2004

The Patient State Index as an indicator of the level of hypnosis under general anaesthesia.

BACKGROUND: This retrospective study describes the performance of the Patient State Index (PSI), under standard clinical practice conditions. The PSI is comprised of quantitative features of the EEG (QEEG) that display clear differences between hypnotic states, but consistency across anaesthetic agents within the state. METHODS: The PSI was constructed from a systematic investigation of a database containing QEEG extracted from the analyses of continuous 19 channel EEG recordings obtained in 176 surgical patients. Induction was accomplished with etomidate, propofol, or thiopental. Anaesthesia was maintained by isoflurane, desflurane, or sevoflurane, total i.v. anaesthesia using propofol, or nitrous oxide/narcotics. It was hypothesized that a multivariate algorithm based on such measures of brain state, would vary significantly with changes in hypnotic state. RESULTS: Highly significant differences were found between mean PSI values obtained during the different anaesthetic states selected for study. The relationship between level of awareness and PSI value at different stages of anaesthetic delivery was also evaluated. Regression analysis for prediction of arousal level using PSI was found to be highly significant for the combination of all anaesthetics, and for the individual anaesthetics. CONCLUSIONS: The PSI, based upon derived features of brain electrical activity in the anterior/posterior dimension, significantly co-varies with changes in state under general anaesthesia and can significantly predict the level of arousal in varying stages of anaesthetic delivery.

Adolescent↗
PubMed2000

EEG controlled rapid opioid withdrawal under general anaesthesia.

We performed rapid opioid detoxification under propofol anaesthesia in 30 opioid addicts, using the opioid receptor antagonist naltrexone. Two strategies to obtain a sufficient depth of anaesthesia and to avoid anaesthetic overdose were evaluated. Patients were allocated randomly to one of two groups. In group 1, the effects of propofol were monitored by observing clinical signs, and in group 2, depth of anaesthesia was controlled using an EEG threshold method. Withdrawal symptoms and post-anaesthetic recovery time were assessed. All patients remained stable and no anaesthetic complications were noted. There were significant differences in the total dose of propofol given (group 1, mean 72 (SD 9) mg kg-1; group 2, 63 (8) mg kg-1; P < 0.01), duration of anaesthesia (318 (53) min vs 309 (42) min; P < 0.05), duration of recovery time (49 (13) min vs 40 (12) min; P < 0.01) and frequency of withdrawal symptoms between groups. In addition, the incidence of side effects was different between groups (62 vs 29 points on a withdrawal symptom scale; P < 0.01). To obtain a sufficient depth of anaesthesia but to avoid inappropriately large doses of anaesthetic, we consider that EEG monitoring is valuable during rapid opioid detoxification.

Anesthesia, General↗
PubMed2000

Effect of estradiol on insulin secreting INS-1 cells overexpressing estrogen receptors.

BACKGROUND: Estrogen has been shown to have profound effects on insulin and glucose metabolism in vivo. Indeed, estrogens were recently shown to modulate ion channel and secretory activities in endocrine cells. DESIGN AND METHODS: To investigate whether estrogenic influences are caused by direct effects on pancreatic beta-cells, we equipped INS-1 insulinoma cells with estrogen receptors and monitored insulin content and Ca(2+) fluxes as well as basal and stimulated insulin secretion upon different stimuli including glucose, the Ca(2+) ionophore ionomycin, the Ca(2+) channel agonist BayK8644, the protein kinase C activator TPA, and the adenylate cyclase activator forskolin. RESULTS AND CONCLUSION: Our data reveal that estradiol has no significant direct effect on proliferation rate, insulin content, basal and stimulated insulin output as well as Ca(2+) fluxes of insulin secreting cells in vitro, indicating that in vivo responses to estrogen on insulin and glucose metabolism result from indirect betacytotropic effects.

Calcium↗
PubMed1999

The human mandibular intercondylar angle measured by computed tomography.

In axial computed tomography it is possible to measure the intercondylar angle at the intersection of the longitudinal axes of the condyles. Published values range from 131 to 165 degrees. This angle was determined here in two groups of patients with (n = 22) and without (n = 12) temporomandibular joint dysfunction. A third group of children (n = 12) aged 4-9 years was included to investigate any age-related change in the angle. In the group of healthy individuals, a range of 105 to 165 degrees was found, with a mean intercondylar angle of 139 degrees. In the group with temporomandibular joint dysfunction the mean angle was 143 degrees with a range from 85 to 170 degrees. No statistically significant relation could be shown between intercondylar angle and joint dysfunction. In the group of children the mean angle was 138 degrees with values ranging from 90 to 180 degrees. No significant differences could be demonstrated among the groups. The absolute value of the intercondylar angle seems to be independent of factors such as sex, age and functional disorders of the joint.

Adolescent↗
PubMed1999

Nephrogenic adenoma: A rare bladder tumor in children.

OBJECTIVE: Nephrogenic adenomas of the urinary bladder are rare benign tumors in children. The purpose of our study was to obtain information about the sex distribution, presenting symptoms, intravesical locations, therapy and recurrence rates in pediatric nephrogenic adenomas. PATIENTS AND METHODS: The records of 3 children with nephrogenic adenoma of the urinary bladder diagnosed between 1990 and 1997 were reviewed to evaluate the initial symptomatology, diagnostic examinations and findings, therapeutic procedures and clinical outcome and recurrence rates. Furthermore our data are compared to the findings of all children reported in the literature. RESULTS: Including the 3 cases reported by us, the data on 18 children with nephrogenic adenoma of the bladder could be analyzed. There was a significant predominance of girls compared to boys (5:1); the medical history in all cases was remarkable for previous bladder surgery 3 months to 7 years prior to tumor diagnosis. Most children presented with unspecific symptoms of gross hematuria, dysuria and bladder instability and in all cases the final diagnosis was established after cystoscopy and histopathologic review of a tumor biopsy specimen. Therapy consisted of transurethral resection in 15 cases, partial cystectomy and open excision in 2 and 1 case, respectively. Tumor recurrence developed in 80% of the children with a latency period of 4 years. CONCLUSIONS: Nephrogenic adenomas represent an epithelial response of the urothelium to chronic inflammation or previous trauma resulting in urothelial metaplasia and the development of papillary lesions. Current treatment of choice consists of transurethral resection and fulguration of the base of the tumor and periodic cystoscopy.

Adenoma↗
PubMed1998

Effects of elevated carbon dioxide environment on calcium metabolism in humans.

BACKGROUND: Chronic respiratory acidosis induced by an elevated carbon dioxide (CO2) environment should provoke hypercalciuria with related total body and subsequent bone calcium losses. We examined this hypothesis in four healthy male volunteers, who were exposed during a 25-d period to an 0.7% CO2 environment within a deep diving isolation chamber. Three months later the same subjects were reexamined during a second campaign being exposed to a 1.2% CO2 atmosphere. METHODS: The subjects received a constant calcium intake (1.4 g.d-1) and vitamin D supplement (1000 IU.d-1) during both campaigns. Calcium balance (oral calcium intake minus urinary and fecal calcium output) was evaluated. Serum calcium concentrations and biomarkers of bone metabolism were measured, in order to evaluate bone turnover. Additionally, the response to an acute oral calcium load was examined as a sensitive measure of changes in calcium metabolism. RESULTS: Both, urinary calcium excretion (from 245 +/- 38 to 199 +/- 31 mg.d-1; mean +/- SE, 0.7% and 1.2%, respectively) and fecal calcium losses (from 1229 +/- 128 to 996 +/- 62 mg.d-1) were significantly reduced in the higher (1.2%) CO2 atmosphere. Although more calcium was retained in the body during the 1.2% than during the 0.7% CO2 campaign, serum calcium concentrations and biomarkers of bone formation were significantly lower in the higher CO2 campaign. Furthermore, bone resorption was slightly increased in the 1.2% experiment. CONCLUSION: Elevated CO2 atmosphere may dose-dependently preserve body calcium without a parallel improvement of bone substance.

Acidosis, Respiratory↗
PubMed1997

Insulinoma cells contain an isoform of Ca2+/calmodulin-dependent protein kinase II delta associated with insulin secretion vesicles.

The Ca2+/calmodulin dependent protein kinase II (CaM kinase II) is thought to play an important part in glucose-stimulated insulin secretion. To determine which of the known subtypes (alpha, beta, gamma, delta) occur in insulin-secreting cells, we amplified all types of CaM kinase II by RT-PCR and found the beta3-, gamma-, delta2- and delta6-subtypes in RINm5F insulinoma cells. None of the other 8 delta-subtypes was present. Antibodies generated against the bacterially expressed association domain of the delta2-subtype recognized the recombinant gamma and delta-subtypes. In INS-1 and RINm5F cells, as well as freshly isolated rat islets, only a 55-kDa protein corresponding in size to the delta2-subtype expressed in NIH3T3 fibroblasts was detected. The delta2-subtype therefore appears to represent the predominant subtype of CaM kinase II present in insulin secreting cells. The enzyme was primarily associated with cytoskeletal structures, and very little was present in the soluble compartment or detergent soluble fraction in INS-1- or RINm5F-cells. An analysis of its subcellular distribution was performed by sucrose and Nycodenz density gradient fractionation of INS-1 cells and detection of CaM kinase II delta by immune blots. The enzyme codistributed with insulin used as a marker for secretory granules but not with the lighter synaptic-like microvesicles detected with an antibody against synaptophysin, plasma membranes (syntaxin 1), lysosomes (arylsulfatase), or mitochondria (cytochrome c oxidase). CaM kinase II delta2 thus is identified as the subtype associated with insulin secretory granules and is likely to be involved in insulin secretion.

Animals↗
PubMed1996

Primary nocturnal enuresis and desmopressin treatment: do psychosocial factors affect outcome?

Twenty-three patients (5 to 15 years of age) with primary nocturnal enuresis were treated with desmopressin (DDAVP) according to a four-step protocol with weekly reductions of daily doses (1 to 0.25 microgram/kg body weight) thus including aspects of behavior-oriented "bladder retention training". The rate of wet nights was significantly reduced while patients were on medication (p < 0.02), but the sample as a whole returned to baseline levels after medication was stopped. Six subjects (26%) were non-responders. A variety of psychological and psychosocial single factors did not significantly affect the outcome. However, a subgroup of seven patients assessed as "psychologically non-distressed" revealed better results both on medication (p < 0.02; reduction 73%) and off medication (p > or = 0.05; reduction 39%) compared to a "distressed" subgroup (N = 16). Both groups showed significant changes in wet nights over the treatment course (p < 0.02 and p > or = 0.002, respectively). There was no clear-cut relationship between laboratory data (urine volume, osmolality, vasopressin) and outcome in wet nights. Data did not suggest a subgroup of patients with particularly low nocturnal vasopressin (AVP) secretion and, thus, high rates of wet nights. Our results corroborated the finding that DDAVP is an effective substance in reducing wet nights in patients with primary nocturnal enuresis. However, with respect to major reductions and long-term results (off medication), these preliminary findings suggest that "psychological distress" seems to be a very important confounding outcome variable. Thus, careful consideration and assessment of psychological and psychosocial aspects of distress are recommended. Eventually, a combination of DDAVP treatment with counseling and/or psychotherapy may significantly improve results for the majority of patients and families.

Adolescent↗
PubMed1996

Possibilities of classification of topographically distributed neurophysiological multi-channel data.

Progress in quantifying states of cerebral function and in the further development of automated EEG processing demands the application of suitable methods for the reduction of neurophysiological multi-channel data as well as their automatic classification. The method used here for reducing multi-channel data was to gain distributions of parametric descriptors from EEG data from computer-aided topographic electroencephalometry (CATEEM), for example the relative and absolute band power in the frequency bands delta, theta, alpha 1, alpha 2, beta 1, beta 2, total power, median and mode frequency, and other parameters. These values were subjected to cluster analysis. The classification of EEG parameters was carried out by means of discrimination analysis and neural networks. The practicability of both procedures was demonstrated in the reduction and classification of EEG data in the context of a normed study involving 104 healthy adults. These data have been used as the basis for a new evaluation study of 60 additional intraoperative EEG recordings obtained with CATEEM. In that newly started study, the effects of sedative and anaesthetic drugs on EEG behavior and psychophysiologic behavior remain to be investigated.

Adult↗
PubMed1989

[Clinical significance of immunoscintigraphy for the diagnosis and treatment of gastrointestinal malignant tumors].

Eighty-one immunoscintigraphy (IS) studies in 80 patients with gastrointestinal malignancies were re-evaluated retrospectively to analyze accuracy and clinical impact of the IS findings. Selection of patients was based upon complete diagnostic records and a clinical follow-up of at least 6 months. The 3 antibody preparations used (99m-Tc labelled complete anti-CEA antibodies (BW 431/26), 111-In labelled F(ab')2-fragments against CEA (BW 431/31), and a mixture of 131-I labelled F(ab')2-fragments against CEA and CA 19-9 (IMACIS-1] yielded equal diagnostic sensitivities (65%, range 60-78%) except for liver metastases. These were preferably detected by the 131-I labelled compound. Best results were gained in local recurrencies of gastrointestinal cancer (12/15 true positive = 80%). Among these were 3 out of the 4 lesions which had been exclusively recognized by IS. Thus IS should be applied in patients with suggested local recurrencies and inconclusive outcome of routine diagnostic workup. A widespread and frequent use of IS (e.g. screening of metastases) cannot be advocated since diagnostic results were not convincing and the immunologic risks of IS (development of human anti-mouse antibodies) are still under discussion.

Antibodies, Monoclonal↗
PubMed1984

Influence of diet on 1,2-dimethylhydrazine metabolism in rat liver.

The metabolism of 1,2-dimethylhydrazine (DMH) was investigated in isolated perfused livers excised from Sprague-Dawley rats fed four semisynthetic diets over two generations. The diets were varied within normal physiological limits, without producing specific deficiencies. Diet was shown to have an influence on the growth of animals and on the cholesterol content and beta-glucuronidase activity in the blood serum. However, diet did not influence the rate of metabolism of DMH or the concentration of metabolites.

Animals↗
PubMed1982

Metabolism of 1,2-dimethylhydrazine in isolated perfused rat liver.

The metabolism of 1,2-dimethylhydrazine (DMH) was investigated in isolated perfused rat liver. The separation of [14C]DMH and its metabolites azomethane (AM), azoxymethane (AOM) and methylazoxymethanol (MAM) was performed by high pressure liquid chromatography (HPLC). The fractions were quantitatively detected by liquid scintillation counting of the radioactivity. It was demonstrated that DMH is highly metabolized by the liver. After 1 h of perfusion, the median amounts of DMH and its metabolites in the medium were: DMH, 16%; AM, 3%; AOM, 42%; MAM, 30% of the given dose. During this time 9.9% and 0.7% of the total radioactivity were eliminated as AM and CO2 in the oxygen stream of the perfusion apparatus; 0.6% were excreted by bile and 12.3% stored in hepatic tissue. The reaction rate (t1/2) of each individual metabolic step was estimated by means of a mathematical kinetic model as follows: DMH leads to AM, 21.8 min; AM leads to AOM, 1.5 min; AOM leads to MAM, 41.5 min; MAM leads to, 611 min. The results are discussed in comparison to in vivo experiments.

1,2-Dimethylhydrazine↗
PubMed1982

[Topochemical and electron microscopical analysis of the pancreas of dogs after pancreatic denervation].

Histochemical and electronmicroscopic findings on chronically and selectively denervated pancreata of 8 dogs are described. Most nerve fibers showed marked degeneration and perineuritis, and there was an inflammation of intrapancreatic ganglia. There was no change in the number of islets or in the A-B-cell ratio. Insulitis frequently has been observed. Both immunohistochemically demonstrable insulin in the B-cells, and glucagon in the A-cells were reduced in relation to that in non-denervated controls. There were single A- and B-cells within the acini in an apparently normal frequency. Many pancreata showed a chronic infiltration and fibroblastic inflammation within the acini but their extent varied considerably between the animals. Intrapancreatic blood vessels were generally dilated, hyperemic, and perivascular fibrosis was seen in some cases; the vessels contained many leucocytes. Acinar cells were often subjected to vacuolic degeneration. Another part of them showed, however, increased appearance of ergastoplasm, mitochondria, and of Golgi apparatus as a sign of increased functional stimulation. There were fibrosis and mononuclear infiltration in the medium-sized and large pancreatic ducts.

Animals↗
PubMed1980

Cell cycle-dependent replication of the DNA of minute virus of mice, a parvovirus.

The formation of double-stranded viral DNA was examined in synchronized cells infected with minute virus of mice in early G1 phase. In the infected cells, a minimum of 50-100 copies of the input single-stranded DNA have been converted to a double-stranded form by mid S phase. In well-synchronized cells, the amount of double-stranded form by mid A phase. In well-synchronized cells, the amount of double-stranded viral DNA detected during G1 is on the order of a few copies per cell or less. When cells are infected in the presence of the thymidine analog, 5-bromodeoxyuridine, viral DNA synthesis is inhibited. However, 5-bromodeoxyuridine does not inhibit host DNA synthesis nor does it prevent replication of viral DNA if added to the infected cells in late S phase. Viral DNA replication first becomes resistant to 5-bromodeoxyuridine inhibition at the beginning of S phase. As 5-bromodeoxyuridine appears to specifically block early steps in viral DNA synthesis but not the subsequent replication of the DNA, the conversion of the input viral genome to a double-stranded form which undergoes further replication appears to be a S phase-specific event.

Animals↗