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Biomedical subjects

B Haslinger

Publications and source records attributed to B Haslinger.

At least 19 recordsLinked to original sources
PubMed2005

"Silent event-related" fMRI reveals reduced sensorimotor activation in laryngeal dystonia.

OBJECTIVE: To study with fMRI the pattern of sensorimotor activation in patients with spasmodic dysphonia (laryngeal dystonia) compared to healthy controls. METHODS: The authors performed fMRI measurements during vocal motor tasks in 12 patients with laryngeal dystonia and compared them with those of 12 healthy volunteers. Patients were scanned before (pre) and after (post) treatment with local injections of botulinum toxin (BTX). They examined two different motor tasks: simple vocalization inducing dystonia and whispering without appearance of dystonic symptoms. To avoid movement artifacts with oral motor tasks, the authors used a silent event-related fMRI approach involving noncontinuous sampling with no data acquisition during task performance. RESULTS: They found reduced activation of primary sensorimotor as well as of premotor and sensory association cortices during vocalization in patients with laryngeal dystonia pre-BTX. This was partly observed also during the asymptomatic whispering task. BTX treatment did not result in reversal of reduced cortical activation. CONCLUSION: fMRI signal is reduced in sensorimotor cortices associated with movement of the affected body part in laryngeal dystonia, supporting a dystonic basis for this voice disorder.

Adult↗
PubMed2005

Transmodal sensorimotor networks during action observation in professional pianists.

Audiovisual perception and imitation are essential for musical learning and skill acquisition. We compared professional pianists to musically naive controls with fMRI while observing piano playing finger-hand movements and serial finger-thumb opposition movements both with and without synchronous piano sound. Pianists showed stronger activations within a fronto-parieto-temporal network while observing piano playing compared to controls and contrasted to perception of serial finger-thumb opposition movements. Observation of silent piano playing additionally recruited auditory areas in pianists. Perception of piano sounds coupled with serial finger-thumb opposition movements evoked increased activation within the sensorimotor network. This indicates specialization of multimodal auditory-sensorimotor systems within a fronto-parieto-temporal network by professional musical training. Musical ''language,'' which is acquired by observation and imitation, seems to be tightly coupled to this network in accord with an observation-execution system linking visual and auditory perception to motor performance.

Adult↗
PubMed2004

Neural correlates associated with impaired disgust processing in pre-symptomatic Huntington's disease.

Disturbances in recognizing facial expressions of disgust have been reported previously in pre-symptomatic and manifest Huntington's disease. Given the substantial role of the insula and basal ganglia in the perception of disgust as revealed by functional imaging, lesion studies and intracerebral recordings, we propose dysfunction within the insula and/or basal ganglia as the underlying neural substrate. Using functional MRI (fMRI), we studied a group of nine pre-symptomatic Huntington's disease gene carriers and nine healthy controls, matched for age, gender, intelligence and years of education, while they were viewing disgusted facial expressions. As control conditions, surprised and neutral expressions were presented. Compared with healthy controls, Huntington's disease gene carriers showed reduced responses within the left dorsal anterior insula during processing of disgusted facial expressions. Moreover, processing of disgust was associated with significant activation of the left dorsal anterior insula and putamen in healthy controls, but not in Huntington's disease gene carriers. Furthermore, behavioural assessment revealed a selective impairment in recognizing facial expressions displaying disgust in Huntington's disease gene carriers. Our finding of dysfunctional decreased insula activation in pre-symptomatic Huntington's disease provides an explanation for the clinical deficit in recognizing facial expression of disgust. Furthermore, it underscores the role of the insula in the emotion of disgust.

Adult↗
PubMed2004

Facial expression recognition and subthalamic nucleus stimulation.

BACKGROUND: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves motor signs in Parkinson's disease. However, clinical studies suggest that DBS of the STN may also affect cognitive and emotional functions. OBJECTIVE: To study the impact of STN stimulation in Parkinson's disease on perception of facial expressions. RESULTS: There was a selective reduction in recognition of angry faces, but not other expressions, during STN stimulation. CONCLUSIONS: The findings may have important implications for social adjustment in these patients.

Adult↗
PubMed2003

Differential modulation of subcortical target and cortex during deep brain stimulation.

The combination of electrical deep brain stimulation (DBS) with functional imaging offers a unique model for tracing brain circuitry and for testing the modulatory potential of electrical stimulation on a neuronal network in vivo. We therefore applied parametric positron emission tomography (PET) analyses that allow characterization of rCBF responses as linear and nonlinear functions of the experimentally modulated stimulus (variable stimulator setting). In patients with electrodes in the thalamic ventrointermediate nucleus (VIM) for the treatment of essential tremor (ET) here we show that variations in voltage and frequency of thalamic stimulation have differential effects in a thalamo-cortical circuitry. Increasing stimulation amplitude was associated with a linear raise in rCBF at the thalamic stimulation site, but with a nonlinear rCBF response in the primary sensorimotor cortex (M1/S1). The reverse pattern in rCBF changes was observed with increasing stimulation frequency. These results indicate close connectivity between the stimulated nucleus (VIM) and primary sensorimotor cortex. Likewise, stimulation parameter-specific modulation occurs at this simple interface between an electrical and a cerebral system and suggests that the scope of DBS extends beyond an ablation-like on-off effect: DBS could rather allow a gradual tuning of activity within a neuronal circuit.

Aged↗
PubMed2002

Subthalamic nucleus stimulation affects striato-anterior cingulate cortex circuit in a response conflict task: a PET study.

The subthalamic nucleus (STN) has generally been considered as a relay station within frontal-subcortical motor control circuitry. Little is known about the influence of the STN on cognitive networks. Clinical observations and studies in animals suggest that the STN participates in non-motor functions which can now be probed in Parkinson's disease patients with deep brain stimulation of the STN, allowing selective and reversible modulation of this nucleus. Using PET, we studied changes in regional cerebral blood flow (rCBF) associated with a response conflict task (Stroop task) in Parkinson's disease patients ON and OFF bilateral STN stimulation. The Stroop task requires subjects to name the font colour of colour words (e.g. "blue") printed in an incongruent colour ink (e.g. yellow). During STN stimulation, impaired task performance (prolonged reaction times) was associated with decreased activation in both right anterior cingulate cortex (ACC) and right ventral striatum. Concomitant increased activation in left angular gyrus indicative of ongoing word processing during stimulation is consistent with an impairment to inhibit habitual responses. ACC and ventral striatum are part of the ACC circuit associated with response conflict tasks. The decreased activation during STN stimulation in the ACC circuit, while response conflict processing worsened, provides direct evidence of STN modulating non-motor basal ganglia-thalamocortical circuitry. Impairment in ACC circuit function could account for the subtle negative effects on cognition induced by STN stimulation.

Adult↗
PubMed2002

A H(2)(15)O positron emission tomography study on mental imagery of movement sequences--the effect of modulating sequence length and direction.

Motor imagery is a state of mental rehearsal of single movements or movement patterns and has been shown to recruit motor networks overlapping with those activated during movement execution. We wished to examine whether the brain areas subserving control of sequential processes could be delineated by pure mental imagery, their activation levels reflecting the processing demands of a sequential task. We studied six right-handed volunteers (39.0 +/- 14 years) with H(2)(15)O positron emission tomography (PET) while they continuously mentally pursued with their right hand one of five sequences differing in complexity (i.e., increases in sequence length, single-finger repetitions, and reversals). Conditions were repeated twice, alternating with two rest scans. Each imagined single motor element was paced at a frequency of 1 Hz. Significant activation increases (P < 0.05, corrected) associated with imagination of right finger movement sequences (conditions I to V combined)--compared to the rest condition--were observed in left sensorimotor cortex (M1/S1) and the adjacent inferior parietal cortex. Further activation increases (P < 0.001, uncorrected) occurred in bilateral dorsal premotor (PMd) cortex, left caudal supplementary motor area, bilateral ventral premotor cortex, right M1, left superior parietal cortex, left putamen, and right cerebellum. Activation decreases occurred in bilateral prefrontal and right temporo-occipital cortex. Activation increases that correlated with sequence complexity were observed only in specific areas of the activated network, notably in left PMd, right superior parietal cortex, and right cerebellar vermis (P < 0.05, corrected). In conclusion, our study, by varying the sequence structure of imagined finger movements, identified task-related activity changes in parietopremotor-cerebellar structures, reflecting their role in mediating sequence control.

Adult↗
PubMed2001

[Acute renal failure due to rhabdomyolysis in McArdle's disease following binge drinking with seizures].

HISTORY AND ADMISSION FINDINGS: A 36-year-old gardener was admitted for tonic-clonic seizures after binge drinking. The next days he developed massive rhabdomyolysis with acute renal failure. Past medical history was unremarkable except for a similar episode of acute renal failure 14 years ago. At that time he had consumed alcohol as well. Furthermore, the patient complained of exercise-related painful muscle cramping and swelling. INVESTIGATIONS: The serum creatinine peaked at 8.5 mg/dl, blood urea at 126 mg/dl and the maximal level of serum creatinine kinase was 108 300 U/l. Because of the massive rhabdomyolysis and the patient inverted question marks past medical history a metabolic myopathy was suspected and a muscle biopsy was performed. Histochemical staining of muscle frozen sections for phosphorylase revealed no activity which is typical for myophosphorylase deficiency (McArdle inverted question marks disease). Additional biochemical analysis of the muscle biopsy specimen confirmed the diagnosis. TREATMENT AND COURSE: By vigorous intravenous hydration and forced alkaline diuresis, the patient had a sufficient urinary output and lacked uremic signs. The serum creatinine and urea fell continuously and reached normal levels after 6 weeks. At that time serum creatinine kinase was still elevated (867 U/l), which is typical for McArdle inverted question marks disease. Avoiding alcohol, a new episode of rhabdomyolysis and acute renal failure did not occur. CONCLUSIONS: Besides exercise alcohol is likely to be a further possible trigger of rhabdomyolysis and acute renal failure in McArdle inverted question marks disease. Postulated mechanisms by which alcohol induces muscle injury include direct muscle toxicity and inhibition of gluconeogenesis, as these patients are probably more dependent on the gluconeogenetic pathway for muscle cell metabolism.

Acute Kidney Injury↗
PubMed2001

Hyaluronan fragments induce the synthesis of MCP-1 and IL-8 in cultured human peritoneal mesothelial cells.

Human peritoneal mesothelial cells (HMC) play an important role in inflammatory processes by their ability to produce various cytokines and chemokines, such as monocyte chemoattractant protein 1 (MCP-1) and interleukin 8 (IL-8). In this study we investigated the effect of experimentally generated hyaluronan (HA) fragments, degradation products of the extracellular matrix component hyaluronan, which accumulate at inflammatory sites, on the expression of MCP-1 and IL-8 in cultured HMC. MCP-1 and IL-8 mRNA expression was determined by RNase protection assays, and protein levels in the supernatants were measured by enzyme-linked immunosorbent assays. HA fragments with a molecular mass of approximately 1-7x10(5) daltons upregulate MCP-1 and IL-8 synthesis in HMC dose and time dependently. The effect of HA fragments could be blocked by Ro31-8220, a specific protein kinase C inhibitor, and by PD98059, an inhibitor of the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway. Upregulation of chemokine synthesis was preceded by an increase in NF-kappaB and AP-1 DNA-binding activity, suggesting that these transcription factors are activated to increase MCP-1 and IL-8 expression by HA fragments. These data demonstrate that HA fragments markedly enhance the mRNA expression and protein synthesis of MCP-1 and IL-8 in HMC. In concert with previous findings, our observations indicate that enhanced levels of HA, which are present in the peritoneal cavity of peritoneal dialysis patients, may account for a locally increased chemokine production.

Adjuvants, Immunologic↗
PubMed2001

Heat-killed microorganisms induce PAI-1 expression in human peritoneal mesothelial cells: role of interleukin-1alpha.

Human peritoneal mesothelial cells (HMCs) have a critical role in maintaining the intraperitoneal balance between fibrinolysis and coagulation by expressing the fibrinolytic enzyme, tissue-type plasminogen activator (tPA), as well as a specific plasminogen activator inhibitor (type 1; PAI-1). During bacterial peritonitis, the balance between intraperitoneal generation and degradation of fibrin is disturbed. As a consequence, severe peritoneal damage occurs, which is one of the leading causes of patient dropout from continuous ambulatory peritoneal dialysis (CAPD) therapy. Cultured HMCs isolated from omental biopsy specimens were used to study the effect of heat-killed strains (2 x 10(8)/mL) of Staphylococcus aureus, Staphylococcus epidermidis, and Escherichia coli on the synthesis of tPA and PAI-1. Conditioned media were obtained by incubating cells with the different bacterial strains. tPA and PAI-1 antigen concentrations were measured in the cell supernatants by enzyme-linked immunosorbent assay. Each of the three heat-killed microorganisms induced a time-dependent increase in PAI-1 synthesis. After a 48-hour incubation period, the strongest effect was seen in the presence of S aureus (3.5-fold versus control), followed by S epidermidis (2.5-fold versus control) and E coli (1.5-fold versus control). Under the same conditions, tPA antigen levels did not change after exposure to S aureus or E coli, whereas the addition of S epidermidis resulted in enhanced tPA antigen production (2-fold versus control). The increase in PAI-1 synthesis in the presence of the heat-killed microorganisms was preceded by similar changes in interleukin-1alpha (IL-1alpha) levels. Inhibiting the activity of IL-1alpha with a neutralizing antibody significantly reduced bacterial-induced PAI-1 production. Our results indicate that the fibrinolytic imbalance during bacterial peritonitis depends on the bacterial species. The increase in PAI-1 synthesis, not the decrease in the production of tPA, alters mesothelial fibrinolytic activity. Because the increase in PAI-1 expression is significantly quenched by blocking the activity of IL-1alpha, the mesothelial release of this cytokine is involved in bacterial-induced changes in the fibrinolytic system.

Bacterial Vaccines↗
PubMed2001

Event-related functional magnetic resonance imaging in Parkinson's disease before and after levodopa.

Event-related functional MRI (fMRI) was used to study blood oxygen level dependent cortical signal changes associated with volitional limb movements off and on levodopa in Parkinson's disease. Eight patients with early stage akinetic Parkinson's disease and eight healthy volunteers underwent three functional imaging runs (high speed echo planar imaging with 600 scans/run) while performing paced single joystick movements in a freely chosen direction every 7-15 s. The non-magnetic joystick was linked to a monitoring system for on-line registration of performance parameters along with timing of the pacing tones and fMRI-scan acquisition parameters. This allowed correlation of movement onset, i.e. event-onset, to scanning time. We repeated the scanning procedure in the Parkinson's disease patients when akinesia improved 30 min after oral levodopa. Compared with the control group, patients both off and on levodopa showed movement-related impaired activation in the rostral supplementary motor area and increased activation in primary motor cortex (M1) and the lateral premotor cortex bilaterally. Levodopa led to a relative normalization of the impaired activation in the mesial premotor cortex and decreased signal levels in M1, lateral premotor and superior parietal cortex. We conclude that levodopa improves impaired motor initiation in the supplementary motor area and decreases hyperfunction of lateral premotor and M1 associated with Parkinson's disease during simple volitional movements.

Aged↗
PubMed2001

Effect of high glucose concentration on the synthesis of monocyte chemoattractant protein-1 in human peritoneal mesothelial cells: involvement of protein kinase C.

Human peritoneal mesothelial cells (HMC) contribute to the activation and control of inflammatory processes in the peritoneum by their potential to produce various inflammatory mediators. The present study was designed to assess the effect of glucose, the osmotic active compound in most commercially available peritoneal dialysis fluids, on the synthesis of the C-C chemokine monocyte chemoattractant protein-1 (MCP-1) in cultured HMC. The MCP-1 concentration in the cell supernatants was determined by enzyme-linked immunosorbent assay and the MCP-1 mRNA expression was examined using Northern blot analysis. Incubation of HMC with glucose (30-120 mM) resulted in a time- and concentration-dependent increase in MCP-1 protein secretion and mRNA expression. After 24 h the MCP-1 synthesis was increased from 2.8 +/- 0.46 to 4.2 +/- 0.32 ng/10(5) cells (n = 5, p < 0.05) in HMC treated with 60 mM glucose. In contrast, osmotic control media containing either the metabolically inert monosaccharide mannitol or NaCl did not influence MCP-1 production. The stimulating effect of high glucose on MCP-1 expression in HMC was mimicked by activation of protein kinase C (PKC) with the phorbol ester PMA (20 nM). Coincubation of the cells with glucose and the specific PKC inhibitor Ro 31-8220 completely blunted glucose-mediated MCP-1 expression. In summary, our results indicate that glucose induces MCP-1 synthesis by a PKC-dependent pathway. Since osmotic control media did not increase MCP-1 release, it is suggested that the effect of glucose is mainly related to metabolism and not to hyperosmolarity. These data may in part explain elevated steady-state levels of MCP-1 found in the dialysis effluent of continuous ambulatory peritoneal dialysis patients.

Cells, Cultured↗
PubMed1999

D-glucose increases the synthesis of tissue-type plasminogen activator (t-PA) in human peritoneal mesothelial cells.

Physical and chemical irritation of the peritoneum through glucose-based hyperosmolar dialysis solutions results in a nonbacterial serositis with fibrinous exudation. Thereby, human peritoneal mesothelial cells (HMC) play an important role in maintaining the balance between the peritoneal generation and degradation of fibrin by expressing the fibrinolytic enzyme tissue-type plasminogen activator (t-PA) as well as the specific plasminogen activator inhibitor-1 (PAI-1). In this study, we analyzed the effect of D-glucose and metabolically inert monosaccharides on the synthesis of t-PA and PAI-1 in cultured HMC. Incubation of HMC with D-glucose or the metabolically inert monosaccharides mannitol and L-glucose (5-90 mM) resulted in a time- and concentration-dependent increase in t-PA mRNA expression and antigen secretion without affecting PAI-1 synthesis. A similar effect was evident when HMC were first exposed sequentially to pooled spent peritoneal dialysis effluent for up to 4 hours, and subsequently incubated for 20 hours in control medium. The stimulating effect of high D-glucose on t-PA expression in HMC was prevented by treating the cells with different protein kinase C (PKC) inhibitors (Ro 31-8220, Gö 6976), but could not be mimicked by the PKC-activating phorbol ester PMA, indicating that this effect of high glucose is dependent on PKC activity, but not mediated through PKC activation. Also, using specific inhibitors (PD 98059, SB 203580) and activators (PMA, anisomycin, IL-1alpha) of the major routes of the mitogen-activated protein kinases (MAPKs) cascade, we found no evidence for a role of this cascade in regulating t-PA expression in HMC. We conclude that hyperosmolarity induces t-PA (but not PAI-1) in HMC via a regulatory mechanism that requires active PKC, but that does not involve a major pathway in the MAPK cascade.

Cells, Cultured↗
PubMed1998

The mosaic bioprosthesis in the aortic position: hemodynamic performance after 2 years.

BACKGROUND: The Mosaic bioprosthesis is a porcine valve combining several new features to improve hemodynamics and durability: a low profile stent for reduced flow obstruction, zero pressure fixation to maintain the natural collagen crimp, and the amino oleic acid antimineralization treatment to enhance durability. METHODS: Fifty-five Mosaic valves were implanted in the aortic position since February 1994. Data from these patients (group 1) were compared with data from 52 patients who had received a Hancock Modified Orifice II aortic valve (group 2). The mean patient age was 72.0 (+/-5.9) years for group 1 and 76.8 (+/-4.7) years for group 2. Clinical examinations including transthoracic echocardiography were performed 6 and 24 months postoperatively. RESULTS: Mild aortic insufficiencies were found in 2 patients in group 1 and in 3 patients in group 2. There were no embolic or bleeding complications. One Mosaic patient required reoperation due to mitral insufficiency. During the reoperation, a small (approximately 3 mm) thrombus was noted on the outflow side of a Mosaic cusp. The valve was removed and replaced prophylactically. In the 2-year follow-up, hemodynamic measurements showed mean pressure gradients of 12.4 mm Hg for the 21 mm, 11.3 mm Hg for the 23 mm, and 15.4 mm Hg for the 25 mm prostheses in the Hancock group. In the Mosaic group, mean pressure gradients were 14.8 mm Hg for the 21 mm, 10.9 mm Hg for the 23 mm, and 11.5 mm Hg for the 25 mm valves. Differences between pressure gradients and effective orifice areas of the Hancock and the Mosaic valves were not statistically significant. Early mortality in group 1 was 3.6% and in group 2 3.8%. Overall mortality was 12.7% and 13.5%, respectively. CONCLUSIONS: The Mosaic valve has low pressure gradients for all sewing ring diameters. Compared with the Hancock Modified Orifice valve, there was no statistically significant gradient difference but a tendency toward better hemodynamics was noted in the Mosaic group after 2 years.

Aged↗
PubMed1998

High glucose increases prostaglandin E2 synthesis in human peritoneal mesothelial cells: role of hyperosmolarity.

Peritoneal mesothelial cells are considered the predominant source of peritoneal prostanoid formation because they represent the largest resident cell population in the peritoneal cavity. The present study was designed to evaluate the effect of D-glucose, which is widely used in commercially available peritoneal dialysis fluids as an osmotic compound, on the synthesis of prostaglandins in cultured human mesothelial cells (HMC). Analysis of eicosanoid synthesis in HMC by reversed-phase HPLC revealed that 6-keto-PGF1alpha, the spontaneous hydrolysis product of prostacyclin (PGI2), and prostaglandin E2 (PGE2) were the main eicosanoids produced. Addition of D-glucose resulted in a time- and concentration-dependent (30 to 120 mM) increase in PGE2 production in HMC (24 h, 90 mM: 3.9+/-0.5 ng/10(5) cells versus 2.3+/-0.3 in untreated cells; P < 0.05). Mannitol (90 mM) or L-glucose (90 mM). nonmetabolizable osmotic compounds, also led to a significant (P < 0.05) but less intense increase in PGE2 synthesis (3.3+/-0.4 and 3.2+/-0.5 ng/10(5) cells, respectively). Increased PGE2 synthesis was completely blunted by coincubation with the specific protein kinase C (PKC) inhibitor Ro 31-8220 or downregulation of PKC activity by preincubation with phorbol myristate acetate for 16 h. Furthermore, coincubation with PD 98059, an inhibitor of the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway, also inhibited increased PGE2 synthesis by D-glucose or mannitol. In contrast, the iso-osmolar glucose polymer icodextrin, which is used as an alternative to D-glucose in peritoneal dialysis solutions, had no effect on PGE2 synthesis. These data indicate that D-glucose and metabolically inert sugars increase PGE2 synthesis in HMC at least in part by hyperosmolarity and that this effect requires activation of PKC and the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway of intracellular signaling.

Arachidonic Acid↗
PubMed1991

[Value of supine thoracic radiography in the diagnosis and quantification of pleural effusions: comparison with sonography].

The purpose of this prospective study was to verify the value of the supine chest radiograph with regard to the recognition and quantification of pleural effusions. The findings of supine chest radiographs were compared to those of chest sonography in a total of 320 pleural cavities. The correct identification and quantification of a pleural effusion was possible by supine chest radiograph alone in only 55% of cases (176/320). In 20% (64/320) supine chest x-ray was falsely negative and in 15% (48/320) falsely positive. In 10% an existing effusion was in fact recognised on supine chest x-ray; however the amount of effusion was wrongly estimated.

Adolescent↗
PubMed1990

Intravenous ofloxacin in severe infections.

The efficacy and tolerance of intravenous ofloxacin was studied in 70 patients suffering from soft tissue infections (n = 33), intra-abdominal abscesses (n = 14), septicaemia (n = 12), pneumonia (n = 9) and brucellosis (n = 2). The average daily dose was 6 mg/kg divided into two doses. Pathogens treated included Enterobacter cloacae (n = 14), Escherichia coli (n = 12), Staphylococcus aureus (n = 13), Pseudomonas aeruginosa (n = 11), Klebsiella pneumoniae (n = 10), Enterococcus faecalis (n = 8) and Streptococcus spp. (n = 5). Most patients had several underlying diseases. Most of the patients had received other antibiotic therapy without success. Clinically, 41% were considered cured, 19% improved and 30% failed to respond. Bacteriologically, pathogens were eradicated in 52.5% and persisted in 22.5%. Adverse reactions included an anaphylactoid reaction, abnormal liver function (n = 13) and insomnia (n = 2). This study suggests that higher doses of ofloxacin may be needed in deep seated infections.

Adolescent↗