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Biomedical subjects

Gerhard Bauer

Publications and source records attributed to Gerhard Bauer.

At least 19 recordsLinked to original sources
PubMed2007

Valproate, weight gain and carbohydrate craving: a gender study.

PURPOSE: To compare the incidence and magnitude of weight gain associated with valproic acid (VPA) monotherapy in male and female epilepsy patients and to determine possible gender-specific differences in frequency of carbohydrate craving, body-composition, glucose homeostasis and lipid metabolism. METHODS: Epilepsy patients on VPA monotherapy were consecutively recruited at the outpatient clinic of the Department of Neurology, Innsbruck Medical University. Weight gain during VPA-therapy, frequency of carbohydrate craving and physical exercise, sociopsychological problems and family history for diabetes were obtained from all patients. Clinical data also comprised body-impedance analysis, body mass index and waist-to-hip ratio. Morning fasting blood samples were drawn to determine serum leptin, glucose and lipid concentrations, as well as insulin, C-reactive protein and TNF-alpha. RESULTS: One hundred and six patients (55 women) were enrolled in the study. Significant weight gain was seen during VPA-therapy in both genders (each p<0.001) with women experiencing increment of weight more frequently and more pronounced than did men. Analyses of patients who gained weight during VPA-therapy revealed significantly higher serum leptin concentrations in women than in men (p<0.001). Women also revealed significantly higher high-density lipoprotein-cholesterol and lower triglyceride concentrations than men (p=0.004 and 0.014, respectively). Frequency of carbohydrate craving was 25.8% in women and 14.3% in men. More women tried to lose or control weight through diet than did men (22.6% versus 7.1%). Moreover, weight gain as a sociopsychological problem was more numorous in women than in men. CONCLUSION: Women are more prone to gain weight during VPA therapy though higher frequency of diet and sociopsychological burden than men, which might possibly be related to leptin-resitance and a higher frequency of carbohydrate craving.

Adult↗
PubMed2006

Meniscal screw fixation provides sufficient stability to prevent tears from gapping.

BACKGROUND: Many meniscal fixation implants have low pull-out forces. It is still unknown if these forces are higher than the forces the implants must resist in vivo. It was hypothesized that meniscal repair with the meniscal screw as an example for a device of low pull-out force significantly reduces tear gapping. METHODS: Longitudinal tears were set in the posterior horn of the medial menisci of porcine knee joints. To observe the tears a translucent placeholder copying the original articular surface replaced the medial tibial plateau. The knees were moved in a loading and motion simulator under various external moments and axial loads and gapping of the tear was registered. The measurements were repeated after fixation of the tears with three ClearFix Screws, which show a low pull-out force of 20N only. FINDINGS: Maximum gapping (median 1.6mm, min/max 1.1/1.8mm) occurred at 200N axial joint load under the combination of a valgus and external rotation moment. Fixation with the ClearFix Screw significantly reduced tear gapping in all load cases. INTERPRETATION: Moderate joint loads only lead to small gaps of meniscal tears. Meniscal fixation with the ClearFix Screw prevents longitudinal meniscal tears from gapping. This could indicate from a biomechanical point of view that fixation implants of low pull-out strength are not in danger of failure in a normal rehabilitation regimen.

Animals↗
PubMed2006

Language lateralization in temporal lobe epilepsy: a comparison between fMRI and the Wada Test.

PURPOSE: Recent studies have claimed that language functional magnetic resonance imaging (fMRI) can identify language lateralization in patients with temporal lobe epilepsy (TLE) and that fMRI-based findings are highly concordant with the conventional assessment procedure of speech dominance, the intracarotid amobarbital test (IAT). METHODS: To establish the power of language fMRI to detect language lateralization during presurgical assessment, we compared the findings of a semantic decision paradigm with the results of a standard IAT in 68 patients with chronic intractable right and left temporal lobe epilepsy (rTLE, n=28; lTLE, n=40) who consecutively underwent a presurgical evaluation program. The patient group also included 14 (20.6%) subjects with atypical (bilateral or right hemisphere) speech. Four raters used a visual analysis procedure to determine the laterality of speech-related activation individually for each patient. RESULTS: Overall congruence between fMRI-based laterality and the laterality quotient of the IAT was 89.3% in rTLE and 72.5% in lTLE patients. Concordance was best in rTLE patients with left speech. In lTLE patients, language fMRI identified atypical, right hemisphere speech dominance in every case, but missed left hemisphere speech dominance in 17.2%. Frontal activations had higher concordance with the IAT than did activations in temporoparietal or combined regions of interest (ROIs). Because of methodologic problems, recognition of bilateral speech was difficult. CONCLUSIONS: These data provide evidence that language fMRI as used in the present study has limited correlation with the IAT, especially in patients with lTLE and with mixed speech dominance. Further refinements regarding the paradigms and analysis procedures will be needed to improve the contribution of language fMRI for presurgical assessment.

Adolescent↗
PubMed2006

Psychiatric comorbidity in juvenile myoclonic epilepsy.

OBJECTIVE: To assess the prevalence of psychiatric disturbances among patients with juvenile myoclonic epilepsy (JME). METHODS: Forty-three patients with JME (22 female, 21 male, mean age 32.4+/-13, range 15-63) were assessed by means of the Structured Clinical Interviews for DSM-IV (SCID-I and SCID-II). Current and lifetime psychiatric diagnoses were assigned. RESULTS: Thirty-five percent of the JME patients suffered from one or more psychiatric disorders (Axis I and Axis II). Personality disorders were present in 23% and Axis I disorders in 19%. Altogether, 47% had a psychiatric disorder at any time of their life. CONCLUSIONS: Psychiatric diagnoses are slightly higher than in representative community samples. The substantially increased number of personality disorders in JME patients might be attributed to frontal lobe deficits.

Adolescent↗
PubMed2005

Prefrontal disturbances as the sole manifestation of simple partial nonconvulsive status epilepticus.

We describe a case of frontal lobe epilepsy with rare nocturnal generalized tonic-clonic seizures and repeated prolonged episodes of altered behavior lasting 1 to 2 days. The changes consisted of poor organizational strategies, impaired set shifting, emotional indifference, reduced motivation, and impairment of emotional decision making. Memory and consciousness were undisturbed, as she was able to follow her profession as a teacher. During the episode, the EEG was marked by right frontal rhythmical spikes and waves with spread to the homologous left region. Behavioral abnormalities and EEG changes were successfully treated with intravenous diazepam. The clinical representation can be ascribed to alterations of prefrontal-subcortical circuits, especially the anterior cingulate and orbitofrontal circuits. This unique case is classified as simple partial nonconvulsive status epilepticus with prefrontal disturbances as the sole manifestation.

Anticonvulsants↗
PubMed2005

Selective survival of peripheral blood lymphocytes in children with HIV-1 following delivery of an anti-HIV gene to bone marrow CD34(+) cells.

Two HIV-1-infected children on antiretroviral therapy were enrolled into a clinical study of retroviral-mediated transfer of a gene that inhibits replication of HIV-1, targeting bone marrow CD34+ hematopoietic stem/progenitor cells. Two retroviral vectors were used, one encoding a "humanized" dominant-negative REV protein (huM10) that is a potent inhibitor of HIV-1 replication and one encoding a nontranslated marker gene (FX) to serve as an internal control for the level of gene marking. Peripheral blood mononuclear cells (PBMC) containing the huM10 gene or FX gene were detected by quantitative PCR at frequencies of approximately 1/10,000 in both subjects for the first 1-3 months following re-infusion of the gene-transduced bone marrow, but then were at or below the limits of detection (<1/1,000,000) at most times over 2 years. In one patient, a reappearance of PBMC containing the huM10 gene, but not the FX gene, occurred concomitant with a rise in the HIV-1 viral load during a period of nonadherence to the antiretroviral regimen. Unique clones of gene-marked PBMC were detected by LAM-PCR during the time of elevated HIV-1 levels. These findings indicate that there was a selective survival advantage for PBMC containing the huM10 gene during the time of increased HIV-1 load.

Adolescent↗
PubMed2005

Computerized tremor analysis of valproate-induced tremor: a comparative study of controlled-release versus conventional valproate.

PURPOSE: Valproate (VPA) induces postural tremor in 6-45% of patients. The characteristics of VPA-induced tremor have not yet been quantitatively assessed, and it is not known whether tremor prevalence or severity is affected by VPA formulation (controlled-release CR-VPA vs. conventional VPA). The aim of this study was quantitatively to assess tremor in epilepsy patients receiving VPA and to compare the effects of two VPA formulations (CR-VPA vs. VPA) on tremor severity. METHODS: In a prospective study, 18 consecutive patients with newly diagnosed focal or generalized epilepsy were assigned to receive alternately either VPA (n=10) or CR-VPA (n=8) monotherapy. Computerized tremor analysis was performed at baseline 1 day before initiating VPA treatment and repeated after a seizure-free period of >or=8 weeks, during which VPA doses had remained stable. Rest and postural tremor were recorded by accelerometry, and surface electromyograms (EMGs) were recorded from the wrist flexors and extensors. RESULTS: At baseline, the two groups had similar postural tremor amplitudes. At follow-up, the CR-VPA group had remained at the same level, whereas VPA subjects exhibited a significant increase in tremor amplitudes (p<0.05) despite comparable VPA doses and comparable plasma VPA concentrations at the time of tremor testing. CONCLUSIONS: This is the first study to assess quantitatively VPA-induced tremor by standardized tremor analysis. These results suggest that CR-VPA may cause less tremorigenic activity as compared with standard VPA. The mechanisms underlying this difference are unclear but may include greater peak-trough variation with VPA than with CR-VPA.

Activities of Daily Living↗
PubMed2005

Hippocampal formation involvement in a language-activation task in patients with mesial temporal lobe epilepsy.

PURPOSE: The study aims to explore the contribution of the hippocampal formation to the retained language-comprehension network in patients with unilateral mesial temporal lobe epilepsy (TLE). METHODS: We performed a functional magnetic resonance (MRI) study based on a language comprehension paradigm in 45 right-handed patients with unilateral mesial TLE and 35 healthy control subjects. Activations in the hippocampal formations in both hemispheres were analyzed for each subject as well as for groups of left TLE, right TLE, and controls. RESULTS: In sum, 82% of TLE patients displayed hippocampal activations. A significant difference in hippocampal activation between left and right TLE was found: Right TLE patients showed increased activity in the left hippocampal formation compared with left TLE patients. In contrast, patients with left TLE did not show increased activity in the right hippocampal formation compared with right TLE patients. In comparison with a healthy control group, right TLE patients activated the left hippocampal formation to a greater extent, whereas patients with left TLE did not activate the right hippocampal formation to a greater degree. These findings point to an increased involvement of the left hippocampal formation during a language-comprehension task in right TLE patients. In contrast, left TLE in right-handed patients seems not associated with an enhanced involvement of the right hippocampal formation in retained language comprehension. CONCLUSIONS: These findings suggest that effective language comprehension in right-handed subjects with TLE depends on the involvement of the left hippocampal formation and underline the risks of postoperative language decline in patients with left TLE.

Adolescent↗
PubMed2005

Predictors for negative attitudes toward subjects with epilepsy: a representative survey in the general public in Austria.

PURPOSE: To assess knowledge of and attitudes toward epilepsy in the Austrian general public and to identify independent predictors of negative attitudes. METHODS: A survey consisting of a representative sample of 2,128 Austrian adults was commissioned. A questionnaire similar to the ones used in earlier studies in other countries was used. The independent influence of socioeconomic variables and of knowledge and concepts about epilepsy on attitudes were analyzed by using logistic stepwise regression procedure. RESULTS: Nearly 10% of respondents expressed negative attitudes toward people with epilepsy. These figures are similar to those of other studies performed in comparable societies. In addition to being male and of low socioeconomic background, having little theoretical knowledge about epilepsy, misconceptions of epilepsy as a form of insanity, and no personal acquaintance with someone with epilepsy independently predispose to unfavorable attitudes toward epilepsy. CONCLUSIONS: Information campaigns on epilepsy are likely to improve attitudes toward epilepsy when they target misconceptions about epilepsy and when they offer opportunities for personal acquaintance with people with epilepsy.

Adult↗
PubMed2004

Valproate therapy and nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease was defined recently as another symptom of insulin resistance. Continuous therapy with valproate can result in increased body weight and insulin resistance, but no data are yet available on a possible relationship between valproate and nonalcoholic fatty liver disease. We here demonstrate in abdominal ultrasound investigations that characteristics of fatty liver disease were present in 61% of valproate-treated patients as compared with 23% receiving carbamazepine therapy.

Adolescent↗
PubMed2004

Collection of a mobilized peripheral blood apheresis product from a patient with mucopolysaccharidosis type VII and subsequent CD34+ cell isolation.

The effectiveness of bone marrow transplantation for lysosomal storage diseases like mucopolysaccharidosis type VII (MPSVII) suggests that a gene therapy strategy targeting autologous hematopoietic progenitor cells could be successful. Given the severe systemic manifestations of MPSVII including storage disease in the bone and bone marrow, it was unclear whether sufficient numbers of hematopoietic progenitor cells (CD34+) could be mobilized into the peripheral circulation and subsequently purified from these patients. As reported here, G-CSF mobilization and apheresis were successful, providing a product of 4 x 10(10) nucleated cells containing 0.3% CD34+ progenitors. CD34+ cells were magnetically separated from the product to a final purity of 85% with a 64% yield. These results indicate that hematopoietic progenitors can safely be gathered from an MPSVII patient in numbers sufficient for the trial of clinical gene therapy applications.

Adult↗
PubMed2004

Long-term prognosis for childhood and juvenile absence epilepsy.

PURPOSE: To analyse prognostic factors for long term seizure remission in patients with childhood (CAE) and juvenile absence epilepsy (JAE). STUDY DESIGN: A retrospective analysis of a hospital based prevalence cohort. METHODS: The cohort consisted of 163 patients (104 females, 59 males) treated at the Universitatsklinik fur Neurologie, Innsbruck between 1970 and 1997. All had absences according to the ILAE classification. Follow up was in 1999 to 2000. We assessed multiple clinical and EEG factors as predictors of outcome and compared a classification according to the predominant pattern of seizure recurrence (pyknoleptic, PA or non pyknoleptic absence, NPA) with the ILAE classification with respect to prognosis. RESULTS: The mean age at seizure onset was 10.9 years (range, 3 to 27); age at follow up was 36.7 years (range, 13 to 81); duration of follow up was 25.8 years (range, 3 to 69). Sixty four patients (39 %) had CAE and 64 (39 %) JAE, while 35 (22%) had typical absences but could not be clearly defined as either CAE or JAE, and were therefore called "the overlap group". Patients with JAE or patients in the overlap group developed more often generalized tonic clonic seizures (GTCS) (p<0.001) and myoclonic attacks (p<0.05) during the course of the disease. At follow up 36 (56 %) of patients with CAE, 40 (62%) with JAE and 19 (54 %) of the overlap group were seizure free for at least two years (p=ns). When classified according to the predominant absence pattern at seizure onset 42 (51%) patients with PA and 53 (65%) with NPA were in remission (p=ns). In a stepwise binary logistic regression analysis the pattern of absence (PA or NPA) together with the later development of additional seizure types (myoclonias or GTCS), but not the CAE/JAE classification was predictive for long term lack of remission with a correct prediction of 66% of all patients. CONCLUSION: Only 58% of patients with absences were in remission after a long term follow up. CAE and JAE are closely related syndromes with large overlap of the age of onset. A classification according to the predominant seizure pattern at onset, together with later development of myoclonic attacks or GTCS is useful in predicting seizure remission in absence epilepsies.

Adolescent↗
PubMed2004

Linguistic deficits following left selective amygdalohippocampectomy: a prospective study.

Language deficits in 10 patients with medically intractable left-sided temporal lobe epilepsy prior to and following selective amygdalohippocampectomy are described. Preoperatively, a pattern of minor linguistic deficits was observed in three patients; isolated minor naming deficits were detectable in one additional patient. Three months after surgery, six patients' linguistic functions were unchanged, whereas in four patients, a significant decline in linguistic functions could be observed. All four patients revealed a very similar language syndrome characterized by reduced language comprehension and fluency, well-articulated speech, frequent word-finding difficulties, circumlocutions, and semantic paraphasias in the absence of any phonological disorder. These deficits remained stable during the 12-month follow-up period. However, magnetic resonance imaging did not show any neocortical lesions outside the resection area. Possible explanations for these findings include neuronal cell loss and deafferentiation in cortical areas, disruption of the basal temporal language area pathways, reorganization of the language network in chronic temporal lobe epilepsy, and neocortical lesions due to the surgical intervention. Furthermore, correlations between linguistic and demographic data for our patients suggest that patients older at epilepsy onset are at greater risk for developing postoperative language deficits.

Adult↗
PubMed2004

Genital automatisms: a video-EEG study in patients with medically refractory seizures.

PURPOSE: Genital automatisms (GAs) are rare clinical phenomena during or after epileptic seizures. They are defined as repeated fondling, grabbing, or scratching of the genitals. The anatomic correlates of GAs have been discussed controversially. The aim of this investigation was to assess the localizing and lateralizing value of GAs. METHODS: The authors studied 207 consecutive patients with intractable seizures referred to a University Hospital for presurgical evaluation between 1998 and 2002: 135 had temporal lobe epilepsy (TLE); 23, frontal lobe epilepsy (FLE); 29, generalized epilepsies (GEs); and 20 had extratemporal or multifocal epilepsy. RESULTS: Twenty-three (11%) of 207 patients showed GAs in 42 (3%) of 1,299 seizures. GAs occurred significantly more often in men (17 of 93, 18%) than in women (six of 114, 5%; p = 0.0037). Twenty-one (16%) of 135 patients with TLE performed GAs, one (4%) of 23 with FLE and one (3%) of 29 with GE. GAs were associated with unilateral hand automatisms in 16 (70%) of 23 and with periictal urinary urge in five (22%) of 23. All patients had amnesia for the performance of GAs. CONCLUSIONS: GAs appear in the ictal or postictal period with impaired consciousness. Men exhibit GAs significantly more often than do women. GAs do not localize or lateralize per se, but may localize seizure onset in the presence of periictal urinary urge or unilateral hand automatisms. They show a tendency to occur more often in TLE.

Adolescent↗
PubMed2003

Cyclic joint loading can affect the initial stability of meniscal fixation implants.

OBJECTIVE: To identify the effect of cyclic joint loads on the initial fixation strength of different meniscal repair techniques. DESIGN: Three different meniscal refixation implants and one suturing technique were tested for initial stability in porcine knee joints after cyclic joint loading. BACKGROUND: Existing studies tested the initial pull out strength of meniscal fixation implants. It remains unknown how such implants perform under cyclic joint loading. METHODS: The Meniscal Fastener, the Meniscal Arrow, the ClearFix Screw, and a horizontal suture (PDS 1) were implanted in 64 porcine knee joints after setting a tear in the posterior horn of the medial meniscus. In one group of each device the menisci were excised directly after implantation and subsequently subjected to a pull out test. The knee joints of the other groups were exposed to 5000 axial load cycles between 10 and 200 N prior to the pull out test. RESULTS: The horizontal suture showed the highest pull out force (103 N, SD 19 N). Arrow (52 N, SD 18 N), Meniscal Fastener (29 N, SD 3 N), and Meniscal Screw (22 N, SD 8 N) failed at significantly lower loads. Cyclic loading led to a decreased initial pull out force only for the horizontal suture (82 N, SD 26 N) and the Meniscal Fastener (23 N, SD 5N). CONCLUSIONS: Cyclic joint loading can lead to reduced fixation strength especially of meniscal refixation implants and sutures with relatively low stiffness. However, it remains unclear which fixation strength is necessary to provide conditions for meniscal healing. RELEVANCE: The current study adds information to the understanding of how meniscal fixation systems perform mechanically especially after cyclic joint loads.

Absorbable Implants↗
PubMed2003

Gapping phenomenon of longitudinal meniscal tears.

OBJECTIVE: To investigate the gapping behaviour of longitudinal meniscal tears. DESIGN: The gap size of longitudinal meniscal tears was measured in porcine knee joints under various joint loading conditions. BACKGROUND: Many meniscal fixation implants have low pull out forces. However, it is unknown if these forces are less than the forces the implants must resist in vivo. It is also unknown if gapping occurs in longitudinally torn menisci and what joint loads induce gapping. METHODS: Longitudinal tears were set in the medial menisci of eight porcine knee joints. To observe the tears an opaque placeholder of the same shape as the original articular surface replaced the medial tibial plateau. The knees were exposed to flexion-extension cycles in a loading and motion simulator under 30 and 200 N axial joint load without external moments, under tibial rotation moments, varus or valgus moments, and combined moments. For each load condition the maximum gap of the tear was registered. RESULTS: Maximum gapping (1.59 mm, SD 0.47) occurred in the 3 cm tear at 200 N axial joint load under the combination of a valgus and external rotation moment. An internal tibial rotation moment produced the smallest gaps in tears of any length and at any axial joint load. CONCLUSIONS: The maximum gap size found in this study and the previously published pull out stiffnesses of meniscal fixation implants reveal maximum forces on the implant in vivo of only 8.4 N. This explains why meniscal tears fixed with implants of low pull out strength can heal. RELEVANCE: The current study shows that moderate joint loads only lead to small gaps of meniscal tears. Clinically, this means that fixation implants of low pull out strength are not in danger of failure in a normal rehabilitation regimen.

Animals↗