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Biomedical subjects

M Preiss

Publications and source records attributed to M Preiss.

17 recordsLinked to original sources
PubMed2005

The influence of low-frequency left prefrontal repetitive transcranial magnetic stimulation on memory for words but not for faces.

Brain imaging studies suggest localization of verbal working memory in the left dorsolateral prefrontal cortex (DLPFC) while face processing and memory is localized in the inferior temporal cortex and other brain areas. The goal of this study was to assess the effect of left DLPFC low-frequency repetitive transcranial magnetic stimulation (rTMS) on verbal recall and face recognition. The study revealed a significant decrease of free recall in word encoding under rTMS (110% of motor threshold, 0.9 Hz) in comparison with sham stimulation (p=0.03), while no significant difference was found with facial memory tests. Our findings support the essential role of the left DLPFC in word but not facial memory and confirm the content specific arrangement of cortical areas involved in semantic memory. As a non-invasive tool, rTMS is useful for cognitive brain mapping and the functional localization of the category specific memory system.

Adult↗
PubMed2002

Invasive pulmonary aspergillosis: effects of early resection in a neutropenic rat model.

OBJECTIVE: Invasive pulmonary aspergillosis is frequent in neutropenic patients. Usually localized in the beginning, the disease spreads and mortality is high despite antifungal treatment. The role of early adjuvant surgery is not clear. Surgery may help to confirm fungal disease, may control fungal disease locally and may prevent systemic spreading. This study examines effects of early resection on survival and dissemination in a rat model of localized invasive pulmonary aspergillosis. METHODS: Forty persistently neutropenic male albino rats were challenged with standardized conidial aspergillus inoculum injected into peripheral lung tissue of the right upper lobe under direct vision. Animals were divided into four groups. Twenty animals were treated with amphotericin B at 1 mg/kg per day beginning 48 h after inoculation, 20 animals were left untreated. In each group half the animals underwent early resection of localized invasive aspergillosis by lobectomy. Animals were checked daily and mortality was recorded up to 28 days after which surviving animals were sacrificed. RESULTS: Significantly higher survival was observed in resected animals in the non-Am B groups (survival: 10 +/- 19% without early resection and 50 +/- 32% with early resection; P = 0.044). However, early resection did not lead to improved survival in animals treated with amphotericin B (survival 70 +/- 29% without early resection and 50 +/- 32% with early resection; P = 0.316). CONCLUSIONS: In this rat model of localized invasive pulmonary aspergillosis effects of early resection on survival could be demonstrated only in animals not receiving amphotericin B treatment.

Amphotericin B↗
PubMed2001

[Multiple heart valve diseases: differential therapeutic considerations].

After more than 40 years of heart valve surgery, the indication for double valve procedures still represents a problem in the presence of an obviously leading single valve disease. If the isolated valves do not already represent a clear indication for surgery then this situation is the best example for a good deal of thought in cardiac surgery and discussion with competent cardiologists.

Adult↗
PubMed1999

Huntington's disease: the relationship between clinical signs, CAG repeats and the atrophy of the caudate nucleus in CT scans.

We compared clinical data from 45 patients with Huntington's Disease (HD) with CAG triplet repeats and the planimetric measurement of the caudate nucleus head area (CNHA) in CT scans. The mean age of patients was 50.4 yrs (SD +/- 10.2), the mean duration of HD 7.4 yrs (4.6), the mean age at the onset of HD 43.1 yrs (11.1). HD started with motor symptoms in 28 patients, with psychiatric symptoms in 14 patients, the history was unknown in 3 patients. The paternal transmission was observed in 29 patients, the maternal one in 12 patients, unknown in 4 patients. The mean number of CAG repeats was 46.6 (6.1). The mean CNHA was 0.4 cm2 (0.1). We found statistically significant reversed correlation between CAG repeats and the age at the onset of HD (p < 0.0001, r -0.6). The earlier onset of HD in patients with the paternal transmission compared to the maternal one was found statistically significant (p < 0.05). This phenomenon was not related to the larger number of CAG triplets in patients with the paternal transmission. No differences either of the age at the onset of HD or numbers of CAG repeats were found between subgroups of HD patients starting with motor or psychiatric symptoms. We also observed the significant reversed correlation between the duration of HD and CNHA measurement (p < 0.001, r -0.5). Even in the earliest stage of HD patients showed the marked atrophy of CNHA.

Atrophy↗
PubMed1998

Nitric oxide inhibits isoprenaline-induced positive inotropic effects in normal, but not in hypertrophied rat heart.

Evidence has accumulated that, in the rat heart, nitric oxide (NO) inhibits beta-adrenoceptor-mediated positive inotropic effects. The aim of this study was to investigate whether this effect of NO may be altered in cardiac hypertrophy. For this purpose we studied the effects of the NO-donor SNAP (S-nitroso-N-acetyl-D,L-penicillamine) on isoprenaline-induced positive inotropic effects in left ventricular strips from three models of cardiac hypertrophy: a) 12-16 weeks old male spontaneously hypertensive rats (SHR) vs. age-matched normotensive Wistar-Kyoto (WKY) rats, b) six weeks old male Wistar WKY-rats sub-totally nephrectomized (SNX) 7 weeks after SNX vs. sham-operated rats (SOP) and c) four weeks old male Wistar WKY-rats supra-renal aortic-banded (AOB, band diameter 1.0 mm) 8 weeks after AOB vs. SOP. In all three models of cardiac hypertrophy the heart weight/body weight ratio was significantly higher than in their respective controls. On isolated electrically driven ventricular strips isoprenaline (10(-10)-10(-5) M) caused concentration-dependent increases in force of contraction. Maximal increases (Emax) were similar in SHR vs. WKY-rats, but reduced in SNX- (2.9+/-0.29 vs. 5.1+/-0.34 mN, p<0.01) and AOB-rats (2.3+/-0.37 vs. 4.2+/-0.33 mN, p<0.01). In control rats (WKY and the respective SOP) the NO-donor SNAP (10(-5) M) caused a significant rightward-shift of the concentration-response curve for isoprenalinel; this rightward-shift could be inhibited by methylene blue (10(-5) M). In ventricular strips of SHR, SNX- and AOB-rats, however, 10(-5) M SNAP failed to significantly affect isoprenaline-induced positive inotropic effect. We conclude that in cardiac hypertrophy effects of NO are attenuated. Such an impairement of the NO-system could contribute to the development and/or maintenance of cardiac hypertrophy.

Adrenergic beta-Agonists↗
PubMed1997

Doppler microembolic signals in children with prosthetic cardiac valves.

BACKGROUND AND PURPOSE: The aim of this study was the evaluation of the prevalence and counts of Doppler microembolic signals (MES) in children with prosthetic cardiac valves and their comparison to those obtained in corresponding adult patients. PATIENTS AND METHODS: Nine children and 43 adults with ATS valves implanted in the aortic position were monitored over both middle cerebral arteries with transcranial Doppler ultrasound. MES were identified on-line according to standard criteria. Heart rate and rhythm, valve type, size and duration, patients' height, International Normalized Ratio, and prevalence of neurological complications were obtained from all study participants. RESULTS: MES prevalence and counts were significantly higher in children compared with adult patients (100% versus 25.5% and 58 [18.5 to 115.5] versus 55 [2 to 10.5], median, 95% CI, respectively). No corresponding differences in valve duration of valve implant were evident, but children has heart rates and were significantly smaller compared with adults. A positive correlation between patients' size, heart rate, and MES counts was noted. CONCLUSIONS: MES counts in children with mechanical prosthetic valves are significantly higher compared with those in corresponding adults. We hypothesize that this is due to (1) the shorter distance between aortic valve and middle cerebral artery, since cavitation bubbles have a short life span and are bound to dissolve with time, and (2) the faster heart rate in children, resulting in a higher number of valve closures per minute.

Adolescent↗
PubMed1997

Time course of high-intensity transient signals in patients undergoing elective heart valve replacement: a prospective study.

BACKGROUND AND AIMS OF THE STUDY: This study was performed to evaluate the time course of intracranial high-intensity transient signals (HITS) in patients undergoing elective heart valve replacement. METHODS: Thirty-three patients were enrolled in this study. The examination protocol included serial (before and at one, five, 90 and 180 days after surgery) monitoring sessions with transcranial Doppler and detailed neurological examination. Monitoring was performed bilaterally over the middle cerebral arteries for one hour per session using 2 MHz probes. Microembolic signals were recognized according to standard criteria and stored on a computer for later evaluation. RESULTS: HITS prevalence increased from 3% preoperatively to 41% on the first postoperative day and remained unchanged during the postoperative period. No influence of the intensity of anticoagulation or valve type on HITS counts was evident. Unilateral monitoring provided adequate results in 83.9% of cases. CONCLUSIONS: The causative role of the valve implant in the pathogenesis of HITS appears certain, since their prevalence dramatically increases following valve implantation. Valve type, duration of valve implant or intensity of anticoagulation did not influence HITS counts. Bilateral monitoring is warranted for accurate evaluation of HITS counts in this patient group.

Aortic Valve↗
PubMed1996

[Neuropsychologic rehabilitation of mental functions using computers].

The authors draws attention to the problem of neuropsychological rehabilitation. He emphasizes the problem of exploiting the patient's experience during rehabilitation into practical life. He provides data on rehabilitation in vivo and in vitro. He reflects on the development of computer rehabilitation of cognitive functions from neuropsychological tests and presents some examples based on Scandinavian experience. The author also draws attention to his own experience with the neuropsychological computer programme TRAIN THE BRAIN and gives an account of the work with this programme. He recommends the use of computer programmes in psychological and neuropsychological practice. He emphasizes their possibilities in patients with traumatic brain damage and the possibility to follow up systematically changes during recovery which are difficult to record in written tests. Changes in recovery which were recorded by the computer programme frequently did not correspond with changes of the mental state of the patient. Rehabilitation computer programmes also enable to activate of psychiatric patients with performance disorders. The author emphasizes possibilities of neuropsychological rehabilitation and recommends its further development in the Czech Republic.

Brain Injuries↗
PubMed1995

[Neuropsychologic examinations and rehabilitation].

The presented paper is focused on substantial features of neuropsychological examinations. The author emphasizes the application of different tests focused on the relationship between the brain and behaviour, but in particular the neuropsychological battery. He describes the Halstead--Reitan battery and possibilities of its application in children. He emphasizes the importance of neuropsychological rehabilitation and differentiates it from mere recording of the process of spontaneous recovery. He characterizes the main neuropsychological factors which affect recovery after traumatic brain damage. He mentions some of his own examples where he used these factors in clinical practice. The author describes also his own experience with computer rehabilitation using the SERMION--Train the Brain programme.

Adolescent↗
PubMed1995

[Neuropsychology of traumatic brain damage in children].

The author deals with the neuropsychology of traumatic brain damage in children. He mentions briefly the development of neuropsychology with regard to problems encountered in children. Based on an analysis of the literature he assesses four basic factors when establishing the diagnosis. These factors are: age, type and extent of damage, duration of coma and posttraumatic amnesia and premorbid personality. The author finds discrepancies between assessment of coma in different experimental publications and emphasizes the practical aspect of these basic factors in clinical reflections. He presents results of studies concerning mild, medium and severe cerebral affections in children. He emphasizes the importance of psychotherapy, neuropsychological rehabilitation and crisis intervention.

Amnesia, Retrograde↗
PubMed1982

Enhancement of specific nitrogenase activity in Azospirillum brasilense and Klebsiella pneumoniae, inhibition in Rhizobium japonicum under air by phenol.

Specific nitrogenase activity in Azospirillum brasilense ATCC 29145 in surface cultures under air is enhanced from about 50 nmol C2H4 X mg protein -1 X h-1 to 400 nmol C2H4 by the addition of 1 mM phenol. 0.5 and 2 mM phenol added increase the rate 5-fold and 4-fold. This enhancement effect is observed only between 2 and 3 days after inoculation, with only a small reduction of the growth of the cells by the phenol added. In surface cultures under 1% O2, nitrogenase activity is slightly reduced by the addition of 1-0.01 mM phenol. Utilization of succinate is enhanced during the period of maximum enhancement of nitrogenase activity by 60% by addition of 1 mM phenol. The cells did not produce 14CO2 from [U-14C] phenol, neither in surface cultures nor in liquid cultures and less than 0.1% of the phenol was incorporated into the cells. A smaller but significant enhancement of nitrogenase activity by about 100% in surface cultures under air was found with Klebsiella pneumoniae K 11 after addition of 1 mM phenol. However, in Rhizobium japonicum 61-A-101 all phenol concentrations above 0.01 mM reduced nitrogenase activity. With 1 mM phenol added activity was reduced to less than 10% with no effect on the growth in the same cultivation system. With this Rhizobium japonicum strain significant quantities of phenol (25 mumol in 24 h by 2 X 10(12) cells) were metabolized to 14CO2, with phenol as sole carbon source. With Azospirillum brasilense in liquid culture under 1% and 2% O2 in the gas phase, no enhancement of nitrogenase activity by phenol was noticed.

Bacteria↗
PubMedDate not supplied

[Aortic dissection in pregnancy in Marfan syndrome--case report and treatment concept].

PATIENTS AND METHODS: Herein we report the case of a 37 year old pregnant women with Marfan syndrome with dilatation of the aorta ascendens of 42 mm preconceptionAl. The dilatation remained stable until 34 weeks of gestation when a aortic dissection (De Bakey type I) occurRed rapidly. The patient underwent a cesarean section and hysterectomy, followed by surgery of the aorta asc. by means of implantation of a valved graft immediately. CONCLUSIONS: The criteria of a dilatation of the aorta ascendens < 40 mm does not identify reliably those patients who are at risk of dissection during pregnancy. A interdisciplinary approach together with obstetricians, cardiologists and cardiac surgeons is mandatory in all cases of Marfan syndrome and pregnancy.

Aortic Dissection↗