Biomedical subjects

M Butz

Publications and source records attributed to M Butz.

At least 19 recordsLinked to original sources

PubMed2006

A simulation model for compensatory plasticity in the prefrontal cortex inducing a cortico-cortical dysconnection in early brain development.

In the present work, an abstract prefrontal cortex simulation model is used to predict compensatory structural alterations of the cortico-cortical connectivity pattern in the normal and pathologic forebrain maturation. The simulation network shows different representative courses of morphogenesis when developing undisturbed or when suffering from disturbing excitatory afferences. The simulative results could be affirmed by an immuno-histochemical study, revealing a qualitatively comparable development of the glutamatergic projection fibre density in gerbils (Meriones unguiculatus) after juvenile and adult methamphetamine intoxication. The simulation model further allows to consider different rearing conditions (enriched-environment model), and claims contradictory effects of an equal disturbance after enriched or impoverished rearing which are in accordance with the experimental findings.

Animals↗

PubMed2005

Task-dependent oscillations during unimanual and bimanual movements in the human primary motor cortex and SMA studied with magnetoencephalography.

The neural mechanisms subserving uni- and bimanual control of movements are not well understood. Nevertheless, recent studies indicate a functional role of oscillatory activity in movement control and point towards a hemispheric asymmetry in motor control. This study specifically addresses the issues of (i) task-relatedness, (ii) hemispheric symmetry, and (iii) frequency specificity of the measures power, cerebro-muscular coherence, and cerebro-cerebral coherence in bilateral primary motor cortex and supplementary motor area (SMA). We have studied 10 right-handed subjects with simultaneous recordings of magnetoencephalography and surface electromyography during different unimanual and bimanual tasks. Using the analysis technique Dynamic Imaging of Coherent Sources (DICS), left and right primary motor cortex and SMA were functionally localized. Power, cerebro-musclar coherence, and cerebro-cerebral coherence between these areas were computed for four frequency bands in each condition and subjected to ANOVA. Results show a task-specific modulation of power and coherence, and further indicate a hemispheric asymmetry in the control of unimanual and bimanual movements. In addition, different frequency bands showed different task-dependent variations. The gamma band (26-40 Hz) showed strongest modulation for cerebro-muscular coherence and was strongest for the isometric contraction conditions. In contrast, the beta band (13-24 Hz) showed the strongest variations between static and dynamic conditions, and seems to play a particular role in movement control. In summary, our results indicate a differential functional role of oscillatory activity and coupling in the motor system.

Adult↗

PubMed2005

[Ratio of confirmed versus suspected occupational diseases as a parameter of quality].

PURPOSE: To evaluate the notifications of suspected causes of occupational diseases (NSC) under quality assurance aspects. METHODS: We retrospectively analysed the NSC assessed by the institutions for statutory accident insurance and prevention (Berufsgenossenschaft) between 1998 and 2002. RESULTS: Physicians were most frequently represented among the 357,050 notifications (60.2 %). The number of notifications dropped continually between 1998 and 2002. The number and quality of the notifications (NSC) depend on the knowledge of the occupational diseases as well as on the knowledge of the insured persons and on their respective occupational histories. The NSC are issued via the statutory social insurance bodies who are in contact with the patients, and the NSC also depend on the present scientific knowledge of the types of relevant diseases. Usually, the physicians were most frequently the notifiers of occupational diseases, with one exception, namely, incapacitating diseases due to damage to vertebral discs of the lumbar spine caused by many years of lifting of carrying heavy loads or of many years of work in an extremely bent position, in which cases the statutory insurance bodies themselves issued the notifications. Altogether 123,262 notifications were confirmed. The average quota of confirmations was > 40 % with physicians issuing the notifications, > 30 % with statutory pension insurance bodies and only approx. 12 % with notifying statutory sickness insurance bodies. The lowest quota of confirmations - namely, only 3 % - concerned the incapacitating vertebral disc disease of the lumbar spine mentioned above. Non-confirmed notifications of suspected occupational diseases involved an estimated cost of at least 58 million Euro. DISCUSSION: On-target improvement of the quality of notification of suspected occupational diseases is possible by exploring several avenues, including on-target assessment of evaluation criteria reporting by the statutory accident insurance bodies concerned and by regular advice rendered to the statutory social insurance bodies by occupational therapists.

Accidents, Occupational↗

PubMed2004

Pathological oscillatory coupling within the human motor system in different tremor syndromes as revealed by magnetoencephalography.

Whole-head MEG-systems and modern spatial-filter-based analysis tools recently provided new possibilities to analyze non-invasively cerebral networks of human tremor syndromes. We compared tremor syndromes in Parkinsonian patients with a typical resting tremor as well as in patients with hepatic encephalopathy (HE) with a postural tremor called "mini-asterixis". In 6 patients with idiopathic Parkinson's disease (PD) we found strong coherence between the electromyography (EMG) of forearm muscles and activity in the contralateral primary motor cortex (M1) at tremor frequency but also at double tremor frequency. Furthermore, significant coherences were observed between M1 and medial wall areas (CMA/SMA), lateral premotor cortex, diencephalon, SII cortex, posterior parietal cortex and the contralateral cerebellum at tremor and, stronger, at double tremor frequency. In contrast, in 6 patients with "mini-asterixis" and HE due to chronic liver cirrhosis excessive corticomuscular coherence occurred at the individual tremor frequency between EMG and M1 activity. Interestingly, thalamus-M1 coupling was significantly altered towards lower frequencies matching the individual frequency of the mini-asterixis. Cerebro-muscular or cerebro-cerebral coupling at double tremor frequency was not observed. Therefore, "mini-asterixis" reflects most likely a pathologically decelerated and augmented synchronized rhythmical motor cortical output. This could be due to functional alterations in the M1-basal-ganglia-thalamo-cortical loops in severe HE. In summary, tremor syndromes in PD as well as in patients with HE and "mini-asterixis" are characterized by pathological oscillatory activity within cerebral networks of motor areas. However, the present study shows different mechanisms of tremor generation in PD and HE patients.

Evoked Potentials, Motor↗

PubMed2003

Mini-asterixis in hepatic encephalopathy induced by pathologic thalamo-motor-cortical coupling.

Recently, it was shown that a slowed motor cortical drive in hepatic encephalopathy (HE) results in mini-asterixis (MA). During forearm elevation, the authors have now investigated the coupling between motor cortex and thalamic activity using magnetoencephalography in six cirrhotic patients with HE and MA and in six control subjects. HE patients showed thalamo-motor-cortical coupling at a significantly lower frequency than the coupling in control subjects. The pathologic motor cortical drive in HE probably results from altered thalamocortical oscillatory coupling.

Aged↗

PubMed2002

[Rehabilitation of burn victims. A difficult path back to normality].

The most important aims of rehabilitation in burn victims is the restitution and improvement of joint mobility, mimicry and pulmonary function, as well as of muscular endurance and strength. In addition to the management of scars, therefore, patient instruction in unsupervised training and scar care, as well as promotion of re-integration into day-to-day life are essential. Depending on the parts of the body affected, measures may include manual therapy, active exercise, treatment with ultrasound, proprioceptive neuromuscular facilitation in the case of facial burns, respiratory therapy and ergotherapy and, finally coordination training. Treatment of the scars themselves requires a combination of a number of measures, all of which should be of an "active" nature. Of proven value are manual massage of scar tissue, stretching exercises, the use of silicone, special splints and compression clothing, as well as laser therapy. Rehabilitation measures should be applied for not less than 4 weeks. Where indicated, further surgical measures should be discussed with the patient.

Bandages↗

PubMed2000

Density of sympathetic axons in sural nerve biopsies of neuropathy patients is related to painfulness.

In this study, differences of unmyelinated nerve fiber density in sural nerve biopsy material from patients suffering from neuropathies of unknown origin with (n=14) or without pain (n=13) were analyzed. Immunocytochemistry was applied to differentiate afferent sensory and efferent sympathetic nerve fibers. All patients were evaluated for deficits of small fiber function with thermotesting, quantitative sudomotor-axon reflex-testing and testing of painfulness of mechanical stimuli before performing the biopsy. No difference was found between patients with and without pain concerning clinical deficits or results in any of the neurophysiological examinations. There were also no histopathological differences concerning the density of afferent C-fibers. However, absolute and relative density of efferent sympathetic nerve fibers was significantly higher in patients with painful neuropathy (P<0.001), although none of the patients demonstrated clinical sympathetic abnormalities. We conclude that an imbalance between afferent and sympathetic nerve fiber density in the periphery may contribute to neuropathic pain even in those patients without obvious clinical autonomic disturbances.

Adult↗

PubMed1998

Expression of a fusion gene consisting of the mouse growth hormone-releasing hormone gene promoter linked to the SV40 T-antigen gene in transgenic mice.

Limited information is available concerning the regulation of growth hormone-releasing hormone (GHRH) gene expression in the hypothalamus, largely because of the lack of a suitable cellular model. In an attempt to immortalize hypothalamic GHRH-producing neurons, we have generated a transgenic mouse model which expresses the simian virus 40 (SV40) T-antigen gene (Tag) under the control of the GHRH gene promoter. The transgene contains approximately 5 kb of mouse GHRH gene sequences, including 3.5 kb of the 5'-flanking region, the entire hypothalamic exon 1 and 1.5 kb of intron 1, fused to the SV40 Tag gene. This construct was microinjected into fertilized oocytes. Fourteen of 96 mice born had integrated the transgene. These mice were fertile and showed no signs of central or peripheral tumors. The pattern of expression of the SV40 Tag gene was analyzed in four different transgenic lines by RT-PCR. The tissues tested include: hypothalamus, pituitary, cortex, cerebellum, spinal cord, adrenal, testis, spleen and lung. Transgene expression was consistently detected in the hypothalamus of all lines. In addition, SV40 Tag expression was also detected in the hypothalamus by Northern blot analysis in two of the transgenic lines. SV40 Tag expression was also detected in the testis of all transgenic lines by RT-PCR. This result was not expected since the GHRH gene sequences present in the transgene do not include the testis-specific transcription initiation site previously described. This suggests that GHRH gene expression in the mouse testis can be directed by regulatory sequences located downstream of the testis specific transcription start site. We conclude that the promoter region of the GHRH gene included in this construct contains the regulatory elements necessary to drive hypothalamic and testis expression in vivo. In addition, all mice from one of the transgenic lines developed cataracts in both eyes. SV40 Tag expression was detected not only in eyes with cataracts, but also, to a lesser extent, in eyes from other transgenic lines. Furthermore, the endogenous GHRH gene was found to be expressed in the eyes of normal mice.

Animals↗

PubMed1993

[Diagnosis and therapy of non-germ cell testicular tumors. Organ preservation or orchiectomy?].

Between 1980 and 1990, 670 testicular examinations were performed. Testicular palpation and ultrasonography were carried out. A total of 588 patients (87.8%) had malignant testicular tumors; 82 patients (12.2%) were found to have nongerminal testicular and paratesticular tumors. Intraoperative frozen section histology and tumor size determined the subsequent procedure. In cases of epidermal cysts, adenomatoid tumors and fibrous pseudotumors, the testicle was preserved in the majority of cases. Leydig's cell tumor, Sertoli's cell tumor and dermoid cysts were removed together with the testicle because it was not clear if they were benign. During the postoperative follow-up period, there was no evidence of local recurrence or metastases in any of the patients.

Biomarkers, Tumor↗

PubMed1992

Long-term experience with transurethral rigid ureteroscopy as a complementary method to extracorporeal shockwave lithotripsy.

Between May 1985 and September 1990, 291 ureteroscopies were performed either for primary or secondary stone therapy or for diagnostic purposes. Rigid ureteroscopes (12.5 or 9.5 French) were used without dilation of the ureteral orifice. 83% of the stones could be removed either by direct extraction or electrohydraulic or ultrasound lithotripsy. The highest failure rates (25.6%) occurred in stones located in the upper ureter, the lowest failure rate (9.6%) resulted from treatment of lower ureteral stones. 3.4% complications were observed such as perforation, leakage, stenosis and septicemia. After an average follow-up of 4.5 months, 1 in 70 patients revealed an ureteropelvic stricture which was treated with open surgery. The ureterorenoscopy represents an effective and low-risk primary and secondary method for treatment of ureteral stones in stone centers using extracorporeal lithotriptors which are exclusively equipped with ultrasound detection devices.

Combined Modality Therapy↗

PubMed1991

Pelvic lipomatosis in a female: diagnosis and initial therapy.

The extremely rare case of pelvic lipomatosis in a women is reported (4 cases in the literature). The patient suffered from symptoms of irritable bladder. Treatment included hysterectomy and extension of the bladder resulting in a significant reduction of frequency. Prognostic criteria of the progressive benign disease and therapeutic modalities are discussed.

Adult↗

PubMed1989

[2,8-dihydroxyadenine urinary calculus: the significance of exact physical calculus analysis].

A 21-year-old female patient was treated with Uralyt-U for 3 months for a radiolucent kidney stone. During this therapy the stone increased significantly in volume. After treatment by ESWL, the stone was analyzed by a chemical method and by X-ray diffraction. Calcium phosphate and urate were detected by the chemical method and 2,8-dihydroxyadenine by X-ray diffraction. This case report emphasizes the importance of precise stone analysis for medical treatment is emphasized.

Adenine↗

PubMed1988

Acute acid load in recurrent oxalate stone formers.

An acute acid load was used to evaluate potential chemical differences of urinary composition in recurrent oxalate stone formers and healthy controls. After intake of ammonium chloride, total calcium, ionized calcium and magnesium increased and citrate decreased significantly in both groups. Differences between stone formers and controls could be demonstrated from the excretion of total calcium, citrate, oxalate and uric acid only after acute acid load, whereas ionized calcium did not improve discrimination. These findings support the stone-promoting role of high acid food as well as the possibility of discriminating recurrent oxalate stone formers from controls by an acute acid-loading test.

Acid-Base Equilibrium↗

PubMed1987

Effect of diuresis on the oxalate excretion and the calcium-oxalate product in non-stone formers.

We studied the effect of variations of fluid intake on the oxalate (Ox) excretion in healthy subjects. The relation of Ox excretion to urine volume was examined. The Ca excretion was measured as well and the ionized Ca and the Ca X Ox product were calculated. With a fluid intake between 800 and 4,200 ml a urine volume between 550 and 4,200 ml was found. We saw a strong correlation between urine volume and Ox excretion and a strong negative correlation between urine volume and urinary Ox concentration. The upper limit of urinary Ox excretion to define hyperoxaluria should therefore be modified by taking the urine volume into consideration or should be replaced by the Ox concentration.

Adult↗

PubMed1986

Metabolic disorders in patients with calcium urolithiasis.

In the last two decades, intensive research work has been done in the field of urolithiasis. Due to improved and extended diagnostic methods, it has been recognized that metabolic disturbances play an important role in stone disease.

Acidosis, Renal Tubular↗

PubMed1986

Rational prevention of calcium urolithiasis.

Considerable progress has been made regarding pathogenesis, diagnosis and conservative management of urolithiasis. The cause of the disease can now be determined in nearly 80% of the patients. New stone formation may be prevented in the majority of patients by selective medical treatment. The metabolic, physicochemical and clinical effects of diet, thiazides, allopurinol, sodium cellulose phosphate and potassium-sodium citrate (Oxalyt-C) are described in detail. Intrinsic problems involved in clinical trial with recurrent stone formers are discussed.

Calcium↗

PubMed1985

The effects of methenamine-hippurate upon urinary risk factors for renal stone formation.

Among the various treatments for renal calcium stone disease, none has been documented to reduce urinary oxalate. Methenamine-hippurate (Hiprex) has been used extensively in the treatment of urinary tract infections and from micropuncture studies in the rat, using para-aminohippurate, it could be expected to reduce the renal secretion of oxalate. A daily dose of 3 g was given orally to 15 healthy subjects for 2 weeks. However, there was no net decrease in the urinary excretion of oxalate, but a risk index based on the urinary content of calcium, magnesium, oxalate, citrate and urine became reduced during treatment. The urinary inhibition of calcium oxalate crystal growth was unaffected. It is concluded that there may be a potential in methenamine-hippurate for the treatment of calcium stone disease, which can only be evaluated, however, by a clinical trial in stone patients.

Anti-Infective Agents, Urinary↗

PubMed1983

[Acute kidney failure in secondary renal oxalosis. Additional indications for a causal connection to xylitol infusions].

A 35 years old female developed a slowly progressive acute renal failure after surgical drainage of a pancreatic abscess. Due to the uncharacteristic course a renal biopsy was performed which revealed a severe obstructive renal oxalosis with concomitant interstitial nephritis. Primary oxalosis was excluded by determination of glyceric and glycolic acid in the urine. Since other preconditions for increased oxalate formation were not present it was considered as an adverse reaction to the parenteral application of xylitol. During 4 weeks of total parenteral nutrition the patient received this sugar alcohol in a dose of 3.0 g/kg/day (total dose 4480 g). In recognition of preceding autopsy studies and recent experimental investigations on the metabolic pathways from xylitol to oxalate the chances and conditions of renal deposition of calcium oxalate after administration of xylitol are discussed.

Acute Kidney Injury↗