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Biomedical subjects

M Berger

Publications and source records attributed to M Berger.

At least 73 records · Page 4Linked to original sources
PubMed2001

Design of a microfabricated magnetic cell separator.

A new magnetic separation idea utilizing several ideas from microfabrication and nanomagnetics is presented. The basic idea comes from our earlier work using asymmetry in obstacles and Brownian motion to effect separation of objetcs [10] by moving them in streams whose angle to the hydrodynamic average velocity is a function of the diffusion coefficient of the object. The device we propose here is not technically a Brownian ratchet device but uses the idea of force which acts at angle to the hydrodynamic flow. In our case, the force is generated by a magnetic field gradient which comes from an array of magnetized wires which lie at an angle 0 to a hydrodynamic field flow. The sum of the hydrodynamic force and the magnetic force create a new vector which as in the case of the Brownian ratchet moves the cell out of the main stream direction.

Animals↗
PubMed2001

[Neurobiological findings in a patient with 48-hour rapid cycling bipolar affective disorder. A case report].

Forty-eight-hour rapid cycling is a rare subclass of affective disorders and entails a regular periodic change of moods. The following case study describes the symptoms, therapy, and outcome of a patient suffering from daily switching between mania and depression along with neurobiological findings correlated to the affective cycles. We found alternating reduction and prolongation of sleep duration during manic and depressive days as well as differences in the amount of REM sleep. Cortisol secretion was regularly increased during depressive days. Regarding thyroid-stimulating hormone (TSH) secretion, the circadian rhythm was absent on depressive days. However, the glucose metabolic rate as measured by positron emission tomography (PET) did not differ on manic and depressive days. The patient reached almost complete remission under treatment with lithium.

Bipolar Disorder↗
PubMed2001

Incidence of blindness in southern Germany between 1990 and 1998.

AIMS/HYPOTHESIS: A reduction of diabetes-related blindness by at least one third was declared a primary objective for Europe in 1989 (St. Vincent Declaration). To ascertain a potential change of incidence rates, we collected data on blindness in a German district (population: about 5 million) over 9 years. METHODS: We obtained complete lists of newly registered blindness-allowance recipients between 1990 and 1998 and population data on Württemberg-Hohenzollern, Germany. We estimated incidence rates of blindness in the general population and the diabetic population. To ascertain any time trend, we applied Poisson regression models. RESULTS: There were 6371 newly registered blindness allowance recipients (1990-1998). Of these 67% were women and 27 % had diabetes. Mean age was 71.7 years. Standardised results in the diabetic population (incidence rates per 100,000 person-years; standard: diabetic population; 95 % CI): 1990: 72 (61;82); 1991: 88 (76;100); 1992: 77 (67;88); 1993: 82 (71;93); 1994: 62 (53;72); 1995: 82 (71;93); 1996: 70 (60;80); 1997: 69 (59;79); 1998: 59 (49;68). The Poisson model estimated a 3 % decrease of incident blindness in the diabetic population for each year (Relative risk per year 0.97; CI: 0.95; 0.99). No significant change could be observed in the non-diabetic population (Relative risk: 0.99; CI: 0.98; 1.00). Relative risks for each year varied between sub-groups according to sex, diabetic status and cause of blindness between 0.94 and 1.01. CONCLUSION/INTERPRETATION: A slight reduction of incident blindness could be shown but a reduction by one third has not been reached. Several possible sources of bias in the data have to be considered.

Adult↗
PubMed2001

A double-blind, randomized and placebo-controlled study on the polysomnographic withdrawal effects of zopiclone, zolpidem and triazolam in healthy subjects.

Rebound effects after withdrawal from hypnotics are believed to trigger their chronic use and to enhance the risk of tolerance and dependence. It was the purpose of this study to investigate the acute polysomnographic withdrawal effects after a 4 week treatment with standard doses of the non-benzodiazepine hypnotics zopiclone and zolpidem compared with triazolam and placebo. Healthy male subjects between 22 and 35 years of age participated in a parallel study design. They received either zopiclone 7.5 mg (n=11), zolpidem 10 mg (n=11), triazolam 0.25 mg (n=10) or placebo (n=7) over 4 weeks in randomized and double-blind order. Sleep EEG was registered during 2 nights before treatment under placebo, on days 1, 27 and 28 of treatment and on days 29,30,41 and 42 under placebo. Total sleep time and sleep efficiency were lower in the 1st night after discontinuation of triazolam (p < 0.05, t-test). After withdrawal from zopiclone or zolpidem slight but not significant rebound effects concerning sleep continuity were observed. Self-rating scales showed minimal rebound insomnia after discontinuation of all three hypnotics. In the placebo group no changes of sleep parameters were observed. Assuming that rebound insomnia is part of a withdrawal reaction, this study indicates that the risks of tolerance and dependency are low when administering zopiclone or zolpidem at the recommended doses.

Adult↗
PubMed2001

Chromosomal abnormalities subdivide ependymal tumors into clinically relevant groups.

Ependymoma occurs most frequently within the central nervous system of children and young adults. We determined relative chromosomal copy-number aberrations in 44 ependymomas using comparative genomic hybridization. The study included 24 intracranial and 20 spinal cord tumors from pediatric and adult patients. Frequent chromosomal aberrations in intracranial tumors were gain of 1q and losses on 6q, 9, and 13. Gain of 1q and loss on 9 were preferentially associated with histological grade 3 tumors. On the other hand, gain on chromosome 7 was recognized almost exclusively in spinal cord tumors, and was associated with various other chromosomal aberrations including frequent loss of 22q. We conclude that cytogenetic analysis of ependymomas may help to classify these tumors and provide leads concerning their initiation and progression. The relationship of these aberrations to patient outcome needs to be addressed.

Adolescent↗
PubMed2001

Migraine treatment outcomes with rizatriptan in triptan-naive patients: a naturalistic study.

BACKGROUND: The 5-hydroxytryptamine(1B/1D) agonists, or triptans, are the newest class of drugs to become available for the acute treatment of migraine. The class currently includes sumatriptan, zolmitriptan, naratriptan, and rizatriptan. The efficacy of rizatriptan in the acute treatment of migraine has been established against placebo and other oral triptans in controlled comparative trials. OBJECTIVE: The US Migraine Assessment Protocol (USMAP) collected data on the use of rizatriptan in a naturalistic setting reflecting clinical practice. This paper presents results for patients enrolled in the USMAP study who had never taken a triptan before the study. METHODS: At enrollment, 216 patients completed a questionnaire describing their responses to their current nontriptan medications. They were then given specially packaged samples of 4 standard 10-mg rizatriptan tablets and 4 orally disintegrating 10-mg rizatriptan tablets (wafers) and were asked to take a different formulation for each of their next 2 attacks, the sequence to be at their discretion. Within approximately 24 hours after taking rizatriptan, patients were to call a toll-free number to report their responses to rizatriptan using an interactive voice-response system. RESULTS: Within 2 hours after initial dosing of rizatriptan, significantly more patients taking either the rizatriptan tablet or the rizatriptan wafer reported onset of pain relief, had become largely symptom free, and were able to resume usual activities compared with their baseline responses to nontriptans (P < 0.05). In addition, compared with their baseline responses to nontriptans, significantly more patients taking either rizatriptan formulation had mild or no pain 2 hours after dosing (P < 0.05). More than twice as many patients taking the rizatriptan tablets or wafers were either somewhat or very satisfied with the medication compared with their satisfaction with nontriptans (P < 0.05). CONCLUSIONS: In the naturalistic setting of this study, migraineurs who had not previously taken a triptan medication reported more rapid relief of pain, more effective pain relief, and more rapid resumption of normal activities when taking rizatriptan tablets or wafers than when taking a nontriptan medication. Patients dissatisfied with their current nontriptan migraine therapy may benefit from treatment with rizatriptan.

Activities of Daily Living↗
PubMed2001

Three-dimensional magnetic resonance spectroscopic imaging of histologically confirmed brain tumors.

The goal of this study was to determine whether presurgical metabolite levels measured by 3D MR Spectroscopic Imaging (MRSI) can accurately detect viable cancer within human brain tumor masses. A total of 31 patients (33 exams, 39 pathology correlations) with brain tumors were studied prior to surgical biopsy and/or resection. The 3D MRSI was obtained with a spatial resolution of 0.2 to 1 cc throughout the majority of the mass and adjacent brain tissue using PRESS-CSI localization. Levels of choline, creatine and NAA were estimated from the locations of the resected tissue and normalized to normal appearing brain tissue. The data were correlated with subsequent histologic analysis of the biopsy tissue samples. Although there were large variations in the metabolite ratios, all regions of confirmed cancer demonstrated significant choline levels and a mean choline/NAA ratio of 5.84 + 2.58 with the lowest value being 1.3. This lowest value is greater than 4 standard deviations above the mean (0.52 +/- 0.13) found in 8 normal volunteers. The choline signal intensities in confirmed cancers were significantly elevated compared to normal appearing brain tissue with a mean ratio of 1.71 +/- 0.69. Spectra with no significant metabolite levels were observed in the non-enhancing necrotic core of the tumor masses. The results of this study indicate that 3D MRSI of brain tumors can detect abnormal metabolite levels in regions of viable cancer and grades and can differentiate cancer from necrosis and/or normal brain tissue.

Biomarkers, Tumor↗
PubMed2001

Calculation of nail plate and nail matrix parameters by 20 MHz ultrasound in healthy volunteers and patients with skin disease.

BACKGROUND/AIMS: The objective, but noninvasive, assessment of the nail plate and nail matrix is of interest in dermatology, and cosmetics as well. These cutaneous structures were investigated with 20 MHz ultrasound. This study was performed to obtain data on normal nails in adults of different age groups, with a left-right comparison, and to investigate nail changes in selected dermatologic diseases. METHODS: Healthy controls (n = 34) and patients with dermatologic complaints and nail disease (n = 37) were included after informed consent. In the control group, 18 woman and 16 men with a mean age of 37.2 years (range 15 to 82 years) were investigated for age- and gender-related differences. Patients with one of the following disorders were investigated: systemic lupus erythematosus (SLE; n = 11), systemic sclerosis (PSS; n = 8), psoriasis (n = 9), chronic hand eczema (n = 5), and others (n = 4). Measurements of length and width of the nail plate and the lunulae were performed with a micrometer device. Sonography was performed with a 20 MHz probe in B-scan mode. RESULTS: The mean nail thickness of healthy controls varied between 0.481 mm (right thumb) and 0.397 mm (left fifth finger). The nail volume and the matrix volume disclosed a positive, but mostly nonsignificant, correlation for all controls. Age-specific differences were investigated for both genders. In men and women, the matrix volume increased significantly with age. The nail and matrix volume was higher in men than in women, independent of age. The left-right comparison disclosed a trend to higher nail and matrix volumes on the right hand. In patients with SLE there was an increase in nail thickness and in matrix volume. Patients with PSS showed a significant decrease in nail thickness and matrix volume. In other diseases the measurements disclosed no confident differences to healthy controls. CONCLUSION: The 20 MHz ultrasound offers a noninvasive method to calculate nail thickness, nail volume and matrix volume in healthy volunteers and in nail disease. Skin diseases show characteristic quantitative changes in these parameters.

Adolescent↗
PubMed2001

Changes in the levels of low-abundance brain proteins induced by kainic acid.

Low-abundance gene products are of interest in proteomic studies, because they are probably involved in disease-related changes and their altered levels or modifications may carry significant biological information. Detection of low-abundance proteins of a proteome is one of the major limitations of proteomics and a scientific challenge. We investigated the changes in the levels of low-abundance rat brain cytosolic proteins after administration of kainic acid, a potent neurotoxin and excitatory amino acid. The cytosolic proteins from controls and animals treated with kainic acid were fractionated on an ion-exchange column. The fractions collected were analyzed by 2D electrophoresis, and the proteins with altered levels were identified by matrix-assisted laser desorption ionization or ion-spray MS. We found a manifold decrease in annexin VII, heat-shock cofactor HOP/p60 and SP-22 and a manifold increase in heparin-binding protein p30. The results suggest, respectively, the involvement of an apoptotic pathway, recruitment of the heat-shock protein machinery, generation of an antioxidant response, and, probably, induction of repair mechanisms. Three of the four proteins with altered levels had not been previously detected in the cytosolic fraction, and detection of the altered levels was possible only after the protein-enriching step.

Animals↗
PubMed2001

Uncontrolled-rate freezing and storage at -80 degrees C, with only 3.5-percent DMSO in cryoprotective solution for 109 autologous peripheral blood progenitor cell transplantations.

BACKGROUND: Although controlled-rate freezing and storage in liquid nitrogen are the standard procedure for peripheral blood progenitor cell (PBPC) cryopreservation, uncontrolled-rate freezing and storage at -80 degrees C have been reported. STUDY DESIGN AND METHODS: The prospective evaluation of 109 autologous PBPC transplantations after uncontrolled-rate freezing and storage at -80 degrees C of apheresis products is reported. The cryoprotectant solution contained final concentrations of 1-percent human serum albumin, 2.5-percent hydroxyethyl starch, and 3.5-percent DMSO. RESULTS: With in vitro assays, the median recoveries of nucleated cells (NCs), CD34+ cells, CFU-GM, and BFU-E were 60.8 percent (range, 11.2-107.1%), 79.6 percent (6.3-158.1%), 35.6 percent (0.3-149.5%), and 32.6 percent (1.7-151.1%), respectively. The median length of storage was 7 weeks (range, 1-98). The median cell dose, per kg of body weight, given to patients after the preparative regimen was 6.34 x 10(8) NCs (range, 0.02-38.3), 3.77 x 10(6) CD34+ cells (0.23-58.5), and 66.04 x 10(4) CFU-GM (1.38-405.7). The median time to reach 0.5 x 10(9) granulocytes per L, 20 x 10(9) platelets per L, and 50 x 10(9) reticulocytes per L was 11 (range, 0-37), 11 (0-129), and 17 (0-200) days, respectively. Hematopoietic reconstitution did not differ in patients undergoing myeloablative or nonmyeloablative conditioning regimens before transplantation. CONCLUSION: This simple and less expensive cryopreservation procedure can produce successful engraftment, comparable to that obtained with the standard storage procedure.

Adolescent↗
PubMed2001

Differential effects of trimipramine and fluoxetine on sleep in geriatric depression.

The effects of trimipramine, a tricyclic antidepressant (TCA) with atypical pharmacological properties, and fluoxetine, a selective serotonine reuptake inhibitor (SSRI), were compared in an exploratory analysis using mood and polysomnographic parameters during a six-week double-blind trial in 19 depressed geriatric patients. In sleep EEG measures, trimipramine demonstrated clear-cut effects on sleep measures resulting in higher values for sleep efficiency, total sleep time, stage 2 sleep, and shorter wake time. Under fluoxetine treatment, the proportion of REM sleep was decreased and REM latency was lengthened, whereas no change in REM sleep parameters was observed in the trimipramine group. The present data suggest that early antidepressant effects of medication occur independently of drug-induced changes in objective measures of sleep, i.e. suppression of REM sleep.

Affect↗
PubMed2001

[Danger of monopolar current in laparoscopic gallbladder surgery].

Monopolar electrosurgery is querried because of the availability of new preparation-techniques in laparoscopic cholecystectomy. The advantage of simple handling, cheap application and high efficiency has to be set against the danger of tissue lesions e. g. the damage of the bile duct as demonstrated by four own cases. Especially the bipolar preparation-method and ultrasonic dissection are safer, but expensive and not as fast and effective as monopolar technique. Laser-heated instruments exist but are not in wide clinical use. The danger of tissue-lesions can be reduced by accurate preparation-principles and caution in dissection of the Calot-triangle.

Adolescent↗
PubMed2001

[Analysis and evaluation of current guidelines for diagnosis and treatment of depressive disorders:].

Depressive disorders are of high clinical and economic relevance in outpatient and inpatient care. For the treatment of depression effective measures are available. However, these methods often are not used because depressive disorders are underdetected or underestimated in their severity. To improve diagnostic and therapeutic processes in the last years different national and international organizations developed guidelines for diagnosis and treatment of depressive disorders (e. g. AHCPR, APA, German Association of Psychiatrists). These guidelines differ substantially in their goals, content, size, specifically in their methodological quality. The Association of the Scientific Medical Societies in Germany (AWMF) and the German Agency for Quality in Medicine (AQUMED) developed a checklist to evaluate the methodological quality of guidelines. This manual was used to describe and analyze the most relevant and actual six guidelines for diagnosis and treatment of depressive disorders. Recommendations for further improvement and implementation of these guidelines are given.

Depressive Disorder↗
PubMed2001

[Parent-child relationship in families with liver-transplantated infants].

Due to progress in transplantation medicine and especially thanks to the possibility of transplantation of a liver lobe from a living donor - usually one parent - even very small children with end-stage liver diseases are transplanted nowadays. But there is little research on how parents cope with this specific situation facing the death of their baby without transplantation during the period of transition to parenthood, how family-relationships and bonding develop after transplantation, how the infants develop mentally and emotionally and what specific psychosocial help these families would need to prevent future problems. Stimulated by clinical experiences with families with liver-transplanted infants, a pilot study with families before liver-transplantation was conducted. The aim of the study was to determine methods of infant research suitable for this clinical population. Based on case-vignettes of the interviews and the clinical work with these families, questions as to transition to parenthood, bonding and liver-transplantation by donation of a lobe of one parent's liver are discussed.

Liver Transplantation↗
PubMed2001

Zoster in patients infected with HIV: a review.

Varicella-zoster virus (VZV), a member of the human herpesvirus family, causes childhood chickenpox (varicella), becomes latent in sensory ganglia, and reactivates years later in immunocompromised and elderly persons to produce shingles (herpes zoster). Early in the AIDS epidemic, zoster was noted in adults and children infected with HIV. Severe and debilitating zoster-associated dermatological, ophthalmic, and neurological complications may occur in patients infected with HIV. Antiviral therapy can modify the duration of zoster and alleviate its attendant complications. Varicella vaccine may boost the immunity and prevent virus reactivation. VZV immune globulin (VZIG) prevents or modifies clinical illness in persons who have been exposed to varicella or zoster.

Adult↗
PubMed2001

c-Abl regulates p53 levels under normal and stress conditions by preventing its nuclear export and ubiquitination.

The p53 protein is subject to Mdm2-mediated degradation by the ubiquitin-proteasome pathway. This degradation requires interaction between p53 and Mdm2 and the subsequent ubiquitination and nuclear export of p53. Exposure of cells to DNA damage results in the stabilization of the p53 protein in the nucleus. However, the underlying mechanism of this effect is poorly defined. Here we demonstrate a key role for c-Abl in the nuclear accumulation of endogenous p53 in cells exposed to DNA damage. This effect of c-Abl is achieved by preventing the ubiquitination and nuclear export of p53 by Mdm2, or by human papillomavirus E6. c-Abl null cells fail to accumulate p53 efficiently following DNA damage. Reconstitution of these cells with physiological levels of c-Abl is sufficient to promote the normal response of p53 to DNA damage via nuclear retention. Our results help to explain how p53 is accumulated in the nucleus in response to DNA damage.

Active Transport, Cell Nucleus↗