Biomedical subjects

U Schneider

Publications and source records attributed to U Schneider.

At least 19 recordsLinked to original sources

PubMed2007

Impact of patient- and disease-specific factors on SLNB in breast cancer patients. Are current guidelines justified?

BACKGROUND: The evidence on which to base guidelines for sentinel lymph node biopsy (SLNB) in breast cancer is still limited. In order to facilitate the further implementation of renewed guidelines, we evaluated patient- and disease-specific factors for their impact on the results of SLNB. MATERIALS AND METHODS: Prospective data acquisition from patients undergoing surgery for primary invasive breast cancer was performed. All patients underwent SLNB using the radiocolloid or the combined technique. The association of patient- and disease-specific factors to detection rate and false-negative rate was calculated using univariate and multivariate analyses (P < 0.05 considered as significant). Calculation of the false-negative rate was based on patients who underwent a backup axillary dissection. RESULTS: Among 455 consecutively enrolled patients, a significant inverse association to the detection rate was found for extracapsular extension of non-SLN metastases, body mass index (BMI), number of involved lymph nodes, pT category, tumor size, and age. A significant association to the false-negative rate to identify macrometastases was found for pT category, tumor size, and grading. Other factors, such as prior surgery, multicentric tumor growth, or vascular invasion, showed no influence. A cut-point analysis revealed that a tumor size of 2 cm separated the collective of patients with the highest significance in regard to the false-negative rate (9% vs. 25%). CONCLUSION: Our results indicate that SLNB can be safely used in elderly and obese patients with multicentric tumors and those having undergone prior surgery for benign breast disease. However, the method should be applied with caution in patients with tumors larger than 2 cm.

Adult↗

PubMed2007

Treatment of central retinal vein occlusion by radial optic neurotomy in 107 cases.

BACKGROUND: To evaluate the potential role of radial optic neurotomy (RON), a new surgical technique has been recently proposed for treating central retinal vein occlusion (CRVO). It is hypothesized that CRVO constitutes a neurovascular compartment syndrome at the site of the lamina cribrosa, which can be alleviated by performing a radial incision at the nasal part of the optic nerve head, relaxing the cribriform plate and the adjacent sclera. METHODS: One hundred and seven patients were treated with RON for CRVO at five collaborating ophthalmologic centers. All patients were evaluated by a standardized protocol. For analysis of the angiographic and fundus findings, reference images were used. Intraoperative and postoperative complications were reviewed. RESULTS: On 55 right and 52 left eyes of 107 patients (55.6% male, 44.4% female) with a median age of 68 years (range 21-91 years), RON was performed. The median follow-up time was 6 months (range 1-24 months). The median preoperative visual acuity (VA) was 0.05 (logMAR 1.3), increasing to a median postoperative VA of 0.08 (logMAR 1.1). Patients with an interval of more than 90 days between RON and onset of CRVO showed no significant change in VA at the 6-month follow-up. Severe peripapillary swelling of the optic nerve head prior to RON resulted in an average increase of 4.2 lines in VA at the 6-month follow-up. Angiographic findings of shunt vessels were seen in 18/30 cases after 12 months and were accompanied by an average improvement of VA of six lines. Visual field tests showed various defects in 86.8% of all cases. In one patient an iatrogenic injury of the central retinal artery occurred (0.9%). CONCLUSION: Despite the potential risk of visual field defects, RON seems to be a quite safe procedure. The majority of patients showed rapid normalization of the morphologic fundus findings, with an improvement in VA uncommon for the natural history of CRVO. No significant change in VA was seen in patients with an interval of more than 90 days between the onset of CRVO and RON. A prospective study is warranted for further investigation.

Adult↗

PubMed2006

Free fermion antibunching in a degenerate atomic Fermi gas released from an optical lattice.

Noise in a quantum system is fundamentally governed by the statistics and the many-body state of the underlying particles. The correlated noise observed for bosonic particles (for example, photons or bosonic neutral atoms) can be explained within a classical field description with fluctuating phases; however, the anticorrelations ('antibunching') observed in the detection of fermionic particles have no classical analogue. Observations of such fermionic antibunching are scarce and have been confined to electrons and neutrons. Here we report the direct observation of antibunching of neutral fermionic atoms. By analysing the atomic shot noise in a set of standard absorption images of a gas of fermionic (40)K atoms released from an optical lattice, we find reduced correlations for distances related to the original spacing of the trapped atoms. The detection of such quantum statistical correlations has allowed us to characterize the ordering and temperature of the Fermi gas in the lattice. Moreover, our findings are an important step towards revealing fundamental fermionic many-body quantum phases in periodic potentials, which are at the focus of current research.

Journal Article↗

PubMed2006

Improvement of cognitive functions in chronic schizophrenic patients by recombinant human erythropoietin.

Schizophrenia is increasingly recognized as a neurodevelopmental disease with an additional degenerative component, comprising cognitive decline and loss of cortical gray matter. We hypothesized that a neuroprotective/neurotrophic add-on strategy, recombinant human erythropoietin (rhEPO) in addition to stable antipsychotic medication, may be able to improve cognitive function even in chronic schizophrenic patients. Therefore, we designed a double-blind, placebo-controlled, randomized, multicenter, proof-of-principle (phase II) study. This study had a total duration of 2 years and an individual duration of 12 weeks with an additional safety visit at 16 weeks. Chronic schizophrenic men (N=39) with defined cognitive deficit (>or=1 s.d. below normal in the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS)), stable medication and disease state, were treated for 3 months with a weekly short (15 min) intravenous infusion of 40,000 IU rhEPO (N=20) or placebo (N=19). Main outcome measure was schizophrenia-relevant cognitive function at week 12. The neuropsychological test set (RBANS subtests delayed memory, language-semantic fluency, attention and Wisconsin Card Sorting Test (WCST-64) - perseverative errors) was applied over 2 days at baseline, 2 weeks, 4 weeks and 12 weeks of study participation. Both placebo and rhEPO patients improved in all evaluated categories. Patients receiving rhEPO showed a significant improvement over placebo patients in schizophrenia-related cognitive performance (RBANS subtests, WCST-64), but no effects on psychopathology or social functioning. Also, a significant decline in serum levels of S100B, a glial damage marker, occurred upon rhEPO. The fact that rhEPO is the first compound to exert a selective and lasting beneficial effect on cognition should encourage new treatment strategies for schizophrenia.

Adult↗

PubMed2006

Permutation entropy improves fetal behavioural state classification based on heart rate analysis from biomagnetic recordings in near term fetuses.

The relevance of the complexity of fetal heart rate fluctuations with regard to the classification of fetal behavioural states has not been satisfyingly clarified so far. Because of the short behavioural states, the permutation entropy provides an advantageous complexity estimation leading to the Kullback-Leibler entropy (KLE). We test the hypothesis that parameters derived from KLE can improve the classification of fetal behaviour states based on classical heart rate fluctuation parameters (SDNN, RMSSD, ln(LF), ln(HF)). From measured heartbeat sequences (35 healthy fetuses at a gestational age between 35 and 40 completed weeks) representative intervals of 256 heartbeats were visually preclassified into fetal behavioural states. Employing discriminant analysis to separate the states 1F, 2F and 4F, the best classification result by classical parameters was 80.0% (SDNN). After additionally considering KLE parameters it was improved significantly (p<0.0005) to 94.3% (ln(LF), KLE_Mean). It could be confirmed that KLE can improve the state classification. This might reflect the consideration of different physiological aspects by classical and complexity measures.

Cardiotocography↗

PubMed2006

Surgical strategies for gastric cancer with synchronous peritoneal carcinomatosis.

BACKGROUND: Gastric cancer frequently spreads to the peritoneal cavity. Whether laparoscopy is useful in planning therapy remains controversial. The aim of this study was to investigate the value of laparoscopy and to develop a therapeutic algorithm. METHODS: Six hundred and sixty consecutive patients with gastric cancer were included in this prospective observational study. The sensitivity of abdominal ultrasonography, computed tomography (CT) and laparoscopy for detecting peritoneal carcinomatosis was compared. The lesions were biopsied and classified as P1, P2 or P3 according to the recommendations of the Japanese Research Society for Gastric Cancer. Prognosis was determined according to the stage of peritoneal carcinomatosis and therapeutic procedure adopted. RESULTS: One hundred and ten (16.7 per cent) of 660 patients presented with synchronous peritoneal carcinomatosis. The sensitivity for detecting peritoneal carcinomatosis was 85 per cent for laparoscopy compared with 19 per cent for ultrasonography and 28 per cent for CT. Patients with P3 disease did not benefit from additional surgery compared with chemotherapy alone. Those with P1 carcinomatosis had improved survival rates after complete resection followed by chemotherapy. CONCLUSION: Laparoscopy improves the detection and classification of peritoneal carcinomatosis, and offers patients with gastric cancer a more individualized and effective therapy.

Algorithms↗

PubMed2006

[A survey on trials focussing on the treatment of cannabis-dependence].

Epidemiological studies show that the prevalence of cannabis use in Germany is approaching that of countries known for their high consumption rate, such as Australia and some parts of the USA. In these countries, the resulting cannabis-related psychosocial damage has led to mainly psychotherapeutic treatment studies (conducted in the past ten years) that will be introduced here. According to these studies, the optimal treatment of cannabis-dependent adults would be a short intervention which consists of a combination of motivational-enhancement and cognitive-behavioural elements as well as individual case-counselling (c. f. "Marihuana Treatment Project"). In parallel to a clear consume-reduction over time, these interventions were associated with abstinence rates between 15 % and 22 % also in longer follow-ups (greater than 12 months). Additionally, an approximately 50 % reduction of cannabis-related problems was described. Without any specific treatment, however, abstinence rates were found to be only between 0 % and 9 %, also without any change in prominent social problems. A similar though less obvious trend occurred in a large multisite study regarding the specific treatment of young people, in which besides motivational and cognitive-behavioural also milieu and family therapeutic interventions were tested (c. f. "Cannabis Youth Treatment"). Unfortunately, there exists no controlled treatment study up to now that considered a relevant psychiatric co-morbidity, which usually accompany cannabis-dependence. Whether the interventions above can be recommended and implemented under German conditions should be further investigated, especially considering the growing number of cannabis-consumers seeking treatment.

Germany↗

PubMed2006

Systems-theory of psychosis--the relevance of "internal censorship".

The different aspects of the neurobiology of psychotic disorders are presently discussed under the perspective of Arvid Calssons neurochemical theory of mesolimbic/cortico-thalamic loops. In this regard the question as to whether--neuropsychologically--a "filter-defect" or a disturbance of "internal censorship" is causative for psychoses. This topic is discussed in the present paper.

Adult↗

PubMed2006

Urinary excretion of deoxypyridinoline in Perthes' disease: a prospective, controlled comparative study in 83 children.

Our aim was to investigate the relationship between urinary excretion of deoxypyridinoline (DPD) as a marker of bone resorption, and Perthes' disease. There were 39 children with Perthes' disease in the florid stage who collected first-morning urine samples at regular intervals of at least three months. The level of urinary DPD was analysed by chemiluminescence immunoassay and was correlated with the radiological stage of the disease as classified by Waldenström, and the severity of epiphyseal involvement according to the classification systems of Catterall and Herring. The urinary DPD levels of a group of 44 healthy children were used as a control. The median urinary DPD/creatinine (CREA) ratio was significantly reduced (p < 0.0001) in the condensation stage and increased to slightly elevated values at the final stage (p = 0.05) when compared with that of the control group. Herring-C patients showed significantly lower median DPD/CREA ratios than Herring-B patients (p = 0.03). The significantly decreased median DPD/CREA ratio in early Perthes' disease indicated a reduced bone turnover and supports the theory of a systemic aetiology. Urinary levels of DPD may therefore be used to monitor the course of Perthes' disease.

Amino Acids↗

PubMed2005

Glassy aging dynamics.

We present time-dependent dielectric loss data for various glass formers below the glass temperature. The observed aging dynamics is described using a modified Kohlrausch-Williams-Watts law taking into account the variation of the relaxation time during aging. It leads to values for the aging relaxation time and stretching exponent, fully consistent with the results from equilibrium measurements performed at higher temperatures. Irrespective of the dynamic process prevailing in the investigated frequency region, the aging dynamics is always determined by the structural relaxation process.

Journal Article↗

PubMed2005

Comparison of modern marker proteins in serum and synovial fluid in patients with advanced osteoarthrosis and rheumatoid arthritis.

Numerous studies have focused on the significance of modern marker proteins in the synovial fluid of the knee joint and in the serum both, for osteoarthritis (OA) and rheumatoid arthritis (RA). The relationship between the serum concentrations and the concentrations in the synovial fluid is still unclear. Synovial fluid and serum samples were obtained from 13 patients with advanced OA and from 8 patients with severe RA and concentrations of MMP-1, MMP-3, MMP-13, TIMP-1, COMP and MIA/CD-RAP were determined. All values were normalized against the total protein concentrations. Serum concentrations of MMP-13 in the RA-group were statistically higher than the synovial values (P<0.05). MMP-13 was the only marker protein that revealed distinct higher levels in the serum than in the synovial fluid. The study design allows only conclusions about advanced stages of RA and OA. Longitudinal investigations may provide further information about the value of MMP-13 as a potential marker to monitor the course of RA and OA.

Aged↗

PubMed2005

Monte Carlo dose calculations for spot scanned proton therapy.

Density heterogeneities can have a profound effect on dose distributions for proton therapy. Although analytical calculations in homogeneous media are relatively straightforward, the modelling of the propagation of the beam through density heterogeneities can be more problematical. At the Paul Scherrer Institute, an in-house dedicated Monte Carlo (MC) code has been used for over a decade to assess the possible deficiencies of the analytical calculations in patient geometries. The MC code has been optimized for speed, and as such traces primary protons only through the treatment nozzle and patient's CT. Contributions from nuclear interactions are modelled analytically with no tracing of secondary particles. The MC code has been verified against measured data in water and experimental proton radiographs through a heterogeneous anthropomorphic phantom. In comparison to the analytical calculation, the MC code has been applied to both spot scanned and intensity modulated proton therapy plans, and to a number of cases containing titanium metal implants. In summary, MC-based dose calculations could provide an invaluable tool for independently verifying the calculated dose distribution within a patient geometry as part of a comprehensive quality assurance protocol for proton treatment plans.

Algorithms↗

PubMed2005

Prediction of gastric cancer lymph node status by sentinel lymph node biopsy and the Maruyama computer model.

AIMS: The extent of lymph node dissection in gastric cancer remains controversial. The Maruyama computer model and the sentinel lymph node biopsy (SLNB) are compared for their value to predict the nodal status and lead to stage-adapted surgery. METHODS: Thirty four patients with stage I-IV gastric cancer underwent both staging procedures. For SLNB, 15 patients underwent endoscopic, peri-tumoural injection of (99m)Tc-colloid, and 19 patients were injected of Patent blue V. All 'hot' or blue sentinel lymph nodes (SLNs) were separately excised and histopathologically assessed. If the SLN was negative after routine staining by H&E, it was processed completely and reanalysed after immunohistochemistry. RESULTS: At least, one SLN was detected by means of SLNB in 33/34 of the patients. The sensitivity to identify a positive nodal status was 22/33 and the specificity/positive predictive value was 10/10 and 22/22. Additional micrometastases or isolated tumour cells in the SLN led to 'upstaging' of 5/15, initially classified as nodal negative by H&E-staining. Using the Maruyama computer model, a sensitivity of 22/23 for the correct prediction of the lymph node involvement was associated with a specificity of 2/10 and a positive predictive value of 22/30. CONCLUSIONS: The clinical impact of the Maruyama computer model is limited due to low specificity and a low positive predictive value, rendering the method less useful as an indicator for individualised surgery.

Diagnosis, Computer-Assisted↗

PubMed2005

[Optimization of staging in colon cancer using sentinel lymph node biopsy].

Routine determination of the nodal status in colon cancer is strongly dependent on the individual quality and technique of histopathological assessment and surgical lymph node dissection. We evaluated whether sentinel lymph node biopsy (SLNB) could contribute to an improvement in staging. At least one SLN (median n=2) was detected (detection rate 84%) in each of 38 of 45 patients with primary colon cancer. Ten of these 38 were found to have lymph node metastases by HE staining (26%), six of them in the SLN. Nine of the 28 patients that were initially nodal-negative by HE revealed one micrometastasis and eight cases of isolated tumor cells by immunohistochemical (IHC) staining (32% upstaging response). Including the IHC-positive cases, 19 of the 38 patients were nodal-positive (50%), 15 of them with tumor-infiltrated SLN (overall sensitivity of SLNB 79%). Using the dye method, SLNB is clinically practicable and leads in the majority of the patients to the detection of SLN. The selective, intensified histopathological assessment of SLN identifies small tumor cell deposits in a relevant percentage of patients with little and clinically practicable effort.

Aged↗

PubMed2005

[The endogenous cannabinoid system. Therapeutic implications for neurologic and psychiatric disorders].

For about 5,000 years, cannabis has been used as a therapeutic agent. There has been growing interest in the medical use of cannabinoids. This is based on the discovery that cannabinoids act with specific receptors (CB1 and CB2). CB1 receptors are located in specific brain areas (e.g. cerebellum, basal ganglia, and hippocampus) and CB2 receptors on cells of the immune system. Endogenous ligands of the cannabinoid receptors were also discovered (e.g. anandamids). Many physiologic processes are modulated by the two subtypes of cannabinoid receptor: motor functions, memory, appetite, and pain. These innovative neurobiologic/pharmacologic findings could possibly lead to the use of synthetic and natural cannabinoids as therapeutic agents in various areas. Until now, cannabinoids were used as antiemetic agents in chemotherapy-induced emesis and in patients with HIV-wasting syndrome. Evidence suggests that cannabinoids may prove useful in some other diseases, e.g. movement disorders such as Gilles de la Tourette's syndrome, multiple sclerosis, and pain. These new findings also explain the acute adverse effects following cannabis use.

Animals↗

PubMed2005

[Accidental intraartrial injection of diacethylmorphine (heroin) in drug addicts -- three case reports].

Accidental intrarterial injections are not uncommon in medical treatments. This is also true for uncontrolled injections by drug-addicts. Since 2002 a number of 600 heavy opiate addicts in Germany are substituted in a country-wide study with pure diacetylmorphine (Heroine). We report the course and outcome of three cases of accidental intraarterial injections of pure diacetylmorphine under controlled conditions. After initial symptoms of vasospasms, all cases were without symptoms within one hour and no obvious loss of tissue was observed. After discussing the literature about medical literature and treatment options in intraarterial injections it is concluded, that the cause of major complications after intraarterial injections may not be the pure diacetylmorphine but additional substances in impure "street-heroin" samples.

Adult↗

PubMed2005

Mood and affect during detoxification of opiate addicts: a comparison of buprenorphine versus methadone.

Twenty-six in-patients with Diagnostic and Statistical Manual version IV (DSM-IV) criteria for opioid dependence were selected at random to receive either a combination of an 11-day low-dose buprenorphine and a 14-day carbamazepine regimen (n = 14) or a combination of an 11-day methadone and a 14-day carbamazepine regimen (n = 12) in a double-blind, randomized 14-day in-patient detoxification treatment. Patients with buprenorphine and carbamazepine showed a significantly better psychological state after the first and second weeks of treatment. Above all, the buprenorphine-treated patients demonstrated a less marked tiredness, sensitiveness and depressive state as well as a more prominent elevated mood during the detoxification process. Seven non-completers (after 7 days: four of 12 = 33.3%; after 14 days: seven of 12 = 58.3%) were treated with methadone and carbamazepine and five non-completers (after 7 days: two of 14 = 14.3%; after 14 days: five of 14 = 35.7%) received buprenorphine and carbamazepine. The difference in the overall dropout rate after day 14 was not significant. The present study supports the hypothesis that the combination of buprenorphine and carbamazepine leads to a better clinical outcome than does a combination of methadone and carbamazepine in the detoxification of opioid addicts with additional multiple drug abuse. The buprenorphine and carbamazepine-regimen provides a more effective short-term relief of affective disturbances than does methadone and carbamazepine. No severe side effects occurred during the treatment period in both groups.

Adult↗

PubMed2005

Oxcarbazepine versus carbamazepine in the treatment of alcohol withdrawal.

In a single-blinded and randomized pilot study efficacy and tolerability of oxcarbazepine versus carbamazepine were investigated in 29 patients during therapy of alcohol withdrawal. No initial differences were found regarding sociodemographic data and alcohol-related parameters, indicating successful randomization. The oxcarbazepine group showed a significant decrease of withdrawal symptoms and reported significantly less 'craving for alcohol' compared to the carbamazepine group. Subjectively experienced side effects, normalization of vegetative parameters and improvement in the cognitive processing speed did not reveal differences for both groups. Therefore, oxcarbazepine might be an interesting alternative to carbamazepine, and having almost no addictive potential, no clinically relevant interaction with alcohol and no prominent sedatory effect, possibly also to other drugs such as benzodiazepines or clomethiazole, in the treatment of alcohol withdrawal syndrome.

Adult↗