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Biomedical subjects

F Mohr

Publications and source records attributed to F Mohr.

At least 19 recordsLinked to original sources
PubMed2001

Synthesis, structure, and reactions of binuclear gold(I) complexes containing two different bridging ligands.

The binuclear cycloaurated compounds [Au(2)(mu-C(6)H(3)-2-PPh(2)-n-Me)(2)] (n = 5, 1a; n = 6, 1b) react with the digold(I) complexes [Au(2)(mu-S(2)CN(n)()Bu(2))(2)] and [Au(2)(mu-dppm)(2)](PF(6))(2) to give heterobridged dinuclear complexes [Au(2)(mu-C(6)H(3)-2-PPh(2)-n-Me)(mu-S(2)CN(n)Bu(2))] (n = 5, 5a; n = 6, 5b) and [Au(2)(mu-C(6)H(3)-2-PPh(2)-n-Me)(mu-dppm)]PF(6), (n = 5, 9a; n = 6, 9b), respectively. Complex 5a exists in the solid state as an infinite zigzag chain of dimeric units with intramolecular Au-Au separations of 2.8331(3) and 2.8243(3) A for independent molecules and intermolecular Au-Au separations of 3.0653(3) and 3.1304(3) A. Both 5a and 5b undergo oxidative addition with halogens to give the heterovalent, gold(I)-gold(III) compounds [XAu(I)(mu-2-Ph(2)PC(6)H(3)-n-Me)Au(III)X(eta(2)-S(2)CN(n)Bu(2))] [n = 5, X = Cl (6a), I (8a); n = 6, X = Cl (6b), Br (7b), I (8b)]. Compound 8a has been shown by X-ray crystallography to contain a gold(III) atom coordinated in a planar array by bidentate, chelating di-n-butyldithiocarbamate, iodide, and the sigma-aryl carbon atom, together with a gold(I) atom that is linearly coordinated by the phosphorus atom of the arylphosphine and by iodide. The intramolecular gold-gold distance of 3.2201(3) A indicates little or no interaction between the metal atoms. In contrast to the behavior of the homobridged complexes 1a and 1b, the heterobridged dithiocarbamate complexes 5a and 5b give structurally similar products on reaction with halogens, irrespective of the position of the ring methyl substituent. Crystal data for [Au(2)(mu-C(6)H(3)-2-PPh(2)-5-Me)(mu-S(2)CN(n)Bu(2))] (5a): triclinic, space group P1 (No. 2), with a = 11.3398(1), b = 15.9750(2), c = 16.4400(3) A, alpha = 91.0735(9), beta = 109.3130(7), gamma = 90.7666(8) degrees, V = 2809.47(6) A(3), and Z = 4. Crystal data for [IAu(I)(mu-2-Ph(2)PC(6)H(3)-5-Me)Au(III)I(eta(2)- S(2)CN(n)Bu(2))] (8a): triclinic, space group P1 (No. 2), with a = 8.6136(2), b = 9.3273, c = 21.1518(4) A, alpha = 84.008(1), beta = 84.945(1), gamma = 75.181(1) degrees, V = 1630.54(6) A(3), and Z = 2.

Journal Article↗
PubMed2001

Effectiveness of two radiofrequency ablation systems in atrial tissue.

OBJECTIVE: The efficacy of the left atrial radiofrequency ablation procedure, for the curative treatment of atrial fibrillation, is dependent upon obtaining a confluent transmural line of hyperthermic cellular death. We compare the in vitro effectiveness of obtaining transmural hyperthermic cellular death (>55 degrees C) of both the Osypka single electrode and Boston Scientific Thermaline multi-electrode radiofrequency systems. METHODS: Isolated cadaver porcine hearts were used to measure epicardial temperatures either 'central' or at the 'edge' in relation to an endocardial applied radiofrequency electrode. Reference set point was 70 degrees C, and 4-6-mm thick atrial tissue was used for all applications. 'Edge' temperatures with the Boston Scientific unit were measured whilst activating both adjacent electrodes. RESULTS: Boston Scientific: Probe temperature closely approximated the set point. 'Central' epicardial temperature was lower than probe temperature until after 40 s application (P<0.05), 55 degrees C was reached at 50 s, maximal mean temperature 63.0+/-8.9 degrees C was reached at 100 s. Epicardial 'edge' temperature remained lower than probe temperature for the entire 120 s (P<0.05). Osypka: Probe temperature tended to overshoot the set point. 'Central' epicardial temperature paralleled and occasionally exceeded probe temperature reaching 55 degrees C within 10 s, maximal mean temperature 76.3+/-12.7 degrees C was reached at 10 s and exceeded the set point thereafter. 'Edge' temperature was no different to probe temperature or 'central' epicardial temperature. The mean epicardial temperatures produced with a 65 degrees C set point was no different to that with the 70 degrees C set point, except for a lower final temperature at 60 s. CONCLUSIONS: The Boston Scientific system (70 degrees C set point) requires a minimum in vitro application of 40 s to transmurally increase 4-6 mm atrial tissue temperature above 55 degrees C, and 120-s duration per application would appear to be a reasonable clinical recommendation. The Osypka system transfers thermal energy more effectively, requiring less than 10 s in vitro to achieve a similar transmural temperature, and a 30-s application can be recommended. However, a tendency to overshoot both probe and set point temperature, suggests that a lower set point of 65 degrees C might be safer and as effective.

Animals↗
PubMed2001

Hemodynamics and early performance of the St. Jude Medical Regent aortic valve prosthesis.

BACKGROUND AND AIM OF THE STUDY: The St. Jude Medical (SJM) Regent heart valve is a new bileaflet prosthetic valve modified from the currently marketed SJM mechanical valve, with a modified external profile that results in a larger geometric orifice area without changing the existing design of the pivot mechanism or blood contact surface areas. The aim of the present study was to report the early hemodynamic and clinical results of an on-going multicenter trial investigating the clinical performance of the Regent mechanical aortic valve prosthesis. METHODS: The early results from 204 patients at 11 centers in North America and Europe who underwent implantation of a Regent mechanical aortic valve prosthesis are described. Clinical status was prospectively recorded, and echocardiography with Doppler performed at hospital discharge, and at two and six months and one year postoperatively. RESULTS: Follow up to date is 109.3 patient-years (average follow up 0.5+/-0.4 years per patient; range: 0 to 1.7 years). NYHA class improved for the group, and there were low rates of clinical adverse effects. Echocardiographic mean pressure gradient at six months was 13.8+/-10.3, 7.4+/-4.1, 5.4+/-3.2, 5.2+/-2.8, 3.4+/-2.3 and 3.6 mmHg, respectively, for 19, 21, 23, 25, 27 and 29 mm valves; effective orifice area was 1.5+/-0.6, 2.0+/-0.7, 2.4+/-1.0, 2.5+/-0.7, 3.6+/-1.4 and 4.8 cm2, respectively. There was a statistically significant decrease in left ventricular mass index between early postoperative (169.1+/-57.7 g/m2) and six months follow up (137.2+/-42.7 g/m2, delta = -30.1+/-42.5 g/m2, p <0.0001). CONCLUSION: The SJM Regent aortic valve has excellent associated hemodynamics with rapid and significant left ventricular mass regression. In all cases of adverse events, rates fell within Objective Performance Criteria guidelines. Long-term clinical assessment is on-going.

Aged↗
PubMed2000

Examination of hemolytic potential with the On-X(R) prosthetic heart valve.

BACKGROUND AND AIM OF THE STUDY: Mechanical valves are known to produce chronic, subclinical hemolysis in most patients. Generally, haptoglobin is reduced to below normal in most patients, while lactate dehydrogenase (LDH) is increased to as much as 200% above the upper normal, sometimes resulting in anemia. The study was designed to investigate the clinical hemolysis of the On-X(R) prosthetic heart valve in a multicenter experience with a standard protocol and a single clinical laboratory. METHODS: Between September 1996 and August 1998, 248 patients underwent isolated valve replacement at 10 European centers. Blood samples were collected from these preoperatively and at 3-6 months and one year postoperatively. All samples were analyzed at a central laboratory, thus assuring poolability of the data. In total, 151 patients were tested at 3-6 months, and 62 at one year. Blood parameters measured were LDH, haptoglobin, hematocrit, total hemoglobin, red cell count and reticulocyte count. Paired analysis was used to compare preoperative baseline values with 3-6-month and one-year values. Data were analyzed with regard to both valve position and size. RESULTS: At 3-6 months and one year after surgery, average values for hematocrit, hemoglobin, red cell count and reticulocyte count were all near the center of the normal range, regardless of valve position or size. Statistically significant increases in red cell count and decreases in reticulocyte count occurred after both aortic valve replacement (AVR) and mitral valve replacement (MVR). These changes were of no clinical importance, but indicate that anemia has not occurred in these patients. At 3-6 months, haptoglobin was reduced to below normal in 86% of both AVR and MVR patients; this also occurred after one year and was statistically significant. Postoperatively, the mean LDH value in AVR was 228 U/l (91% of upper normal, 250 U/l) at 3-6 months, and 246 U/l (98% of upper normal) at one year. In MVR, these LDH values were 271 U/l (108% of upper normal) and 265 U/l (106% of upper normal). CONCLUSIONS: These results indicate that the On-X valve causes lower levels of chronic hemolysis in the immediate postoperative period and up to one year after surgery, especially when compared with reports of LDH elevations up to 200% of upper normal. Hemolytic anemia has not occurred in this patient population.

Aortic Valve↗
PubMed1999

[Neuropsychological deficits in the initial acute episode of schizophrenia. A comparison with chronic schizophrenic patients].

By administering an extensive battery of neuropsychological tests, cognitive performance of 66 patients with first episode schizophrenia, 49 patients with chronic schizophrenia and 40 healthy controls has been assessed in the areas of memory functions, speech and cognitive flexibility/abstraction. The three groups were comparable with regard to age, gender and education. Both patient groups showed a significant generalized neuropsychological impairment relative to controls. Patients with first episode were most impaired in visual motor processing and attention (VSM). Besides impairment in VSM, performance in abstraction/flexibility was significantly worse in chronic schizophrenics compared to first episode schizophrenics. Our findings suggest that neuropsychological functions are already impaired at the onset of the illness. Whether cognitive impairment in performance that is attributed to frontal dysfunctions is deteriorating during the course of the illness or is predicting an unfavourable course can only be answered by prospective follow-up studies.

Acute Disease↗
PubMed1998

Neuropsychological impairment and psychopathology in first-episode schizophrenic patients related to the early course of illness.

The objective of the present study was to explore whether the early course of illness including first onset of psychotic symptoms influences neuropsychological functioning and psychopathology in first-episode schizophrenics. Patients with a short prodromal period (n = 20) and patients with a long prodromal period (n = 20) and controls matched with regard to age, gender and education (n = 40) were administered a battery of standardized neuropsychological tests and psychopathological rating scales. The results indicate an overall difference in neuropsychological performance with the schizophrenic patients scoring lower than controls. Schizophrenic patients scored significantly lower in all subtests except in visual memory and abstraction/flexibility than controls. No significant difference between neuropsychological performance between patient samples was found. Psychopathology was more pronounced in the long prodromal period group rating higher on negative and affective symptoms compared with the short prodromal period group. The data suggests that neuropsychological deficits in first-episode schizophrenia are independent of the early course of schizophrenia, and although negative symptoms are associated with the length of the prodromal period, they do not imply greater neuropsychological impairment.

Adult↗
PubMed1998

The prevalence of acute extrapyramidal signs and symptoms in patients treated with clozapine, risperidone, and conventional antipsychotics.

BACKGROUND: Acute extrapyramidal side effects (EPS) are a common phenomenon of treatment with conventional antipsychotics. Previous studies found that clozapine has little propensity to cause EPS, while risperidone produces some EPS, but at levels lower than those of conventional antipsychotics. METHOD: We compared the prevalence and severity of EPS in patients treated with clozapine, risperidone, or conventional antipsychotics for at least 3 months. Our main hypothesis was that there would be differences between the three treatment groups with regard to akathisia, measured with the Barnes Akathisia Scale, and extrapyramidal motor side effects (rigidity, rigidity factor, tremor, salivation), measured with the Simpson-Angus scale. Secondarily, we were interested in possible differences between the three groups with respect to the anticholinergic comedication and the subjective impression of the patients, measured with the van Putten scale. RESULTS: We studied 106 patients (41 patients treated with clozapine, 23 patients with risperidone, and 42 patients treated with conventional antipsychotics). The sample was 57.5% male and had a mean +/- SD age of 36.6 +/- 9.3 years. The mean dose of antipsychotics calculated in chlorpromazine equivalents was 425.6 +/- 197.1 mg/day in the clozapine group, 4.7 +/- 2.1 mg/day in the risperidone group, and 476.5 +/- 476.9 mg/day in the group treated with conventional antipsychotics. The point-prevalence of akathisia was 7.3% in the clozapine group, 13% in the risperidone group, and 23.8% in the group treated with conventional antipsychotics. The point-prevalence of rigidity and cogwheeling respectively was 4.9% and 2.4% in the clozapine group, 17.4% and 17.4% in the risperidone group, and 35.7% and 26.2% in the group treated with conventional antipsychotics. CONCLUSION: Our results indicate that risperidone is superior to conventional neuroleptics in that it causes fewer EPS. In comparison to clozapine, risperidone produces EPS levels that are intermediate between clozapine and conventional antipsychotic drugs.

Acute Disease↗
PubMed1997

Are there gender differences in neuropsychological performance in patients with first-episode schizophrenia?

To investigate gender differences in neuropsychological (NP) functioning in first episode (FE) schizophrenia, consecutively recruited patients with FE schizophrenia (37 males, 29 females) and a subsample of these patients (20 males, 20 females), individually matched for gender, age, and education to healthy controls (20 males, 20 females) were compared on a battery of standardized neuropsychological tests. Women performed better than men in tests of verbal memory and learning, and men performed better than women in spatial organization. However, no differences were present between schizophrenic patients and controls, except that male and female schizophrenic patients showed the most pronounced impairment in visual motor processing, attention and verbal memory and learning. Our data suggest that gender does not appear markedly to modify the cognitive impairment characteristic of schizophrenia. However, they underline the necessity of controlling confounding factors on NP performance such as gender and education.

Adult↗
PubMed1997

[Comparative studies of the rate of restenosis after implantation of Palmaz-Schatz and AVE-Micro stents].

Late results of interventional procedures utilizing coronary stents are largely determined by the rate of restenosis. So far few data are available addressing the effect of stent design, implantation pressure and morphologic factors on this crucial variable. Therefore we analyzed the coronary angiograms obtained in 259 patients before, immediately after and at 3 to 6 months following stent implantation for obstructive coronary disease. A total of 196 AVE-Micro-Stents and 142 Palmaz-Schatz-Stents were implanted into 307 stenoses. In 126 stenoses there were implanted only Palmaz-Schatz-Stents, in 170 only AVE-Micro-Stents and in 11 stenoses there were implanted Palmaz-Schatz- as well as Micro-Stents. Restenosis was defined as an over 50% stenosis at follow up. No significant difference was detected with regard to global restenosis rate at an average of 4 months following implantation (Palmaz-Schatz 33%, Micro-Stent 27%). If results were analyzed according to implantation pressure however, there was a significantly lower restenosis rate for AVE-Micro-Stents implanted with > 10 atm (17%) as compared to < or = 10 atm (35%, p < 0.02) and as compared to Palmaz-Schatz-Stents (34%, p < 0.02), which were also implanted with high pressure over 10 atm. In addition to implantation pressure, vessel segment and morphology of stenosis proved to be important determinants of late results. In this series of patients the AVE-Micro-Stent compared favourably to the Palmaz-Schatz-Stent not only with respect to a significantly lower restenosis rate, when implanted with pressures > 10 atm, but also with regard to its superior flexibility and handling characteristics.

Aged↗
PubMed1996

Neurological soft signs in schizophrenia: assessment and correlates.

A German version of the Neurological Evaluation Scale (NES) was administered to 143 schizophrenic patients, 45 of them being severly chronic and disabled. Seventy-eight alcohol-dependent inpatients and 57 healthy volunteers were tested as control groups. Neurological soft signs (NSS) were rated with convincing agreement. Schizophrenic patients are more impaired on all scales than healthy controls. The chronic, severly disabled schizophrenic patients are more impaired compared with the main group of schizophrenic patients and both control groups. A significant difference between the main group of schizophrenic patients and alcohol-dependent patients was only found for the subscale "Motor Coordination". Compared with healthy controls the alcohol-dependent patients show a higher NES total score. The NES total score was related to the relative width of the third ventricle. Total score and subscales were correlated consistently with the level of cognitive functioning as measured by the Raven Standard Progressive Matrices and various neuropsychological tests presumably sensitive to dysfunctions of the prefrontal cortex. The NSS were related to positive as well as to negative symptoms, the correlations with negative symptoms being confined to items of "Cognitive Disorganization". This close association of psychomotor and cognitive dysfunctions may be seen as related to the frequently discussed dysfunctions of the prefrontal cortex or the neurointegrative deficit postulated by Meehl.

Adult↗
PubMed1996

Neuropsychological impairment in first-episode and chronic schizophrenic patients.

Patients with first-episode (FE) schizophrenia (n = 40), with chronic schizophrenia (n = 40) and healthy controls (n = 40) matched for age, gender, education and parental socioeconomic status were administered a battery of standardized neuropsychological (NP) tests. Both patient groups showed generalized impairment relative to controls and the most pronounced deficits in visual-motor processing and attention (VSM). Compared with FE patients, chronic schizophrenics performed worse in VSM and abstraction/flexibility. Our findings suggest that NP deficits are fundamental manifestations of the illness, and that mainly frontally based dysfunctions are more prominent in chronic, kraepelinian patients.

Acute Disease↗
PubMed1996

Contrasts in neuropsychological test profile between patients with first-episode schizophrenia and first-episode affective disorders.

Patients with first-episode (FE) schizophrenia (n = 27), unipolar depression (n = 10) and bipolar disorder (n = 17) and age- and gender-matched healthy control subjects (n = 27) were administered a battery of neuropsychological (NP) tests. FE schizophrenics performed significantly less well than patients with affective disorders in the area of visual motor processing and attention. Affective disorder patients without psychotic features did not perform significantly differently to controls. However, affective disorder patients with psychotic features performed as poorly as schizophrenics, with the most pronounced impairment in the area of visual motor processing and attention. Our data tentatively suggest the existence of a dichotomy in neuropsychological impairment, with psychotic patients showing similar neuropsychological deficits, while non-psychotic affective patients perform comparably to controls.

Adult↗
PubMed1995

Electrodermal and vascular orienting response in schizophrenic patients: relationship to symptoms and medication.

Peripheral indicators of autonomic nervous system activity, including electrodermal activity and finger-pulse volume, were investigated in 100 schizophrenic inpatients. Healthy siblings of the patients and healthy subjects matched for age and gender served as control groups. Acoustic stimuli (70 dB) were presented and orienting response (OR) parameters were determined independently for the two response systems. The relationship of both OR measures to negative symptoms and medication was studied. The two OR measures were found to be not interrelated, i.e. most of the subjects were discordant with regard to presence or absence of their OR in the two different response systems. The electrodermal, but not the vascular OR, differed between patients and control groups. Among patients receiving medication with anticholinergic effects there were significantly more electrodermal nonresponders than among patients without such medication. There was no indication that electrodermal nonresponders show more negative symptoms or generally more severe psychopathology than electrodermal responders.

Adult↗
PubMed1994

Smooth-pursuit eye movement dysfunction in schizophrenia: the role of attention and general psychomotor dysfunctions.

Smooth-pursuit eye-tracking performance was examined in 100 schizophrenic patients and various control groups under both attention-enhancing and attention-distracting conditions. The level of attentional demand was varied by introducing a secondary reaction time task that directed attention either toward or away from the visual-tracking target. Distraction from the target led to a significant deterioration of tracking performance in all subjects, which was most pronounced in the group of schizophrenic patients. Attention-enhancement, on the other hand, did not normalize performance in this group. In schizophrenic patients, mainly in the distraction condition, there was a moderate association between performance in tracking and tests presumably measuring prefrontal functions. Tracking accuracy from both conditions was related to general motor performance as measured by the Neurological Evaluation Scale. It was concluded that in schizophrenic patients attentional factors (distraction) may contribute to eye-tracking impairment, and that the impairment may be viewed as an aspect of general motor dysfunctions.

Adolescent↗
PubMed1992

[Drug management and therapy resistance. A cross-sectional study of schizophrenic patients in a large psychiatric hospital].

In a cross-sectional study 473 schizophrenic patients of a great psychiatric hospital were served. It was looked for differences in patients' characteristics and pharmacotherapy according to the therapeutic-functional structure of the hospital (admission-Unit, sociotherapeutic and long-time wards). Differences in drug-management became evident on basis of a regimen, which applies high doses (number of psychotropic drugs, chlorpromacin-units) in general, despite recommendations in the literature. The treatment refractory patients in the long-time wards are found to be heterogeneous and the authors suggest alternative pharmacological and psychosocial interventions.

Adult↗
PubMed1991

[Non-selective digital subtraction angiography of aortocoronary bypasses].

Intra-arterial DSA was performed on 225 patients with a total of 552 coronary bypasses (515 aorto-coronary venous bypasses and 37 internal mammary artery bypasses). Four hundred and ninety-five bypasses were examined in the four weeks following surgery; of these, 428 (85.9%) were patent. Demonstration of the distal anastomosis was obtained in 40.4% of bypasses of the right anterior interventricular artery and in 36.1% of the right coronary artery, at least in their proximal parts. Bypasses of smaller branches showed filling in 12.8 to 19.2%. Because of the unsatisfactory demonstration of distal vessels by non-selective intra-arterial DSA, this method is suitable only for showing the patency of a bypass in the postoperative phase, but should not be used for investigating cardiac signs and symptoms following a bypass examination.

Adult↗
PubMed1990

[Surgery in esophageal atresia. Anatomical and functional aspects].

The first successfully operated newborn with esophageal atresia dates back more than 55 years. During this period the concept of the unity of structure and function for surgical treated malformations has been retained. Primary anastomosis offers the best prerequisites. Main life threatening complications are leakage of the anastomosis, anastomotic strictures and gastroesophageal reflux. Avoiding vital complications the aim of undisturbed function can be achieved by appropriate surgical methods. The report describes own experiences over the past 20 years.

Anastomosis, Surgical↗