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Biomedical subjects

A Moritz

Publications and source records attributed to A Moritz.

At least 73 records · Page 4Linked to original sources
PubMed2000

Two years' clinical experience with a quadrileaflet stentless bioprosthesis in the mitral position.

BACKGROUND AND AIMS OF THE STUDY: Currently available bioprosthetic mitral valves do not provide sufficient durability. A new stentless pericardial prosthesis was designed for better hemodynamic performance and reduction of stress load compared with current stented bioprostheses. METHODS: Between September 1997 and August 1999, the Quadrileaflet mitral valve (QMV) was implanted in 17 patients at our institution. Four patients had minimally invasive mitral valve replacement. Mean patient age was 62.2 +/- 16.3 years; preoperative NYHA class was 3.06 +/- 0.2; ejection fraction was 64.1 +/- 14.7%. Echocardiography was performed pre-, intra- and postoperatively, and at 3-6, 12 and 24 months follow up. RESULTS: Fifteen patients had an uneventful intra- and postoperative course. Two patients died, one from acute left heart failure at 6 h after surgery, and one on the first postoperative day after resuscitation for ventricular fibrillation. A small-sized prosthesis was implanted in four patients, medium-sized in eight and large-sized in five. The mean duration of cardiopulmonary bypass was 138.3 +/- 37.0 min; mean cross-clamp time was 91.3 +/- 26.3 min. Postoperative control echocardiography showed a mean valve orifice area of 2.5 +/- 0.4 cm2, transvalvular velocity (Vmax) was 1.6 +/- 0.4 m/s, and mean pressure gradient 3.6 +/- 2.0 mmHg. Echocardiographic evaluation after 3, 6 and 12 months showed no significant difference compared with the intraoperative data. Three patients had a minor mitral regurgitation (grade I-II). At 12 months all patients were in NYHA class I or II. CONCLUSION: The implantation technique of the QMV is more demanding, but the prosthesis is a promising alternative to conventional biological mitral valve replacement. Further follow up is needed to confirm these favorable mid-term results.

Adult↗
PubMed1999

Effects on oral soft tissue produced by a diode laser in vitro.

BACKGROUND AND OBJECTIVES: This investigation determined incision characteristics and soft-tissue damage resulting from standardized incisions using a wide range of laser modes and parameters of a diode laser at 810 nm. STUDY DESIGN/MATERIALS AND METHODS: Histologic examinations were performed to verify vertical and horizontal tissue damage as well as incision depth and width. RESULTS: Incision depth and width correlated strongly with average powers, but not with laser parameters or the used tips. No laser damage was visible to the naked eye in the bone underlying the incisions in the range between 0.5-4.5 W. CONCLUSION: The remarkable cutting ability and the tolerable damage zone clearly show that the diode laser is a very effective and, because of its excellent coagulation ability, useful alternative in soft-tissue surgery of the oral cavity.

Animals↗
PubMed1999

Effect of internal thoracic artery preparation on blood loss, lung function, and pain.

BACKGROUND: Postoperative blood loss, respiratory distress, and pain after coronary artery operation were assessed in a prospective, randomized, clinical study comparing two techniques of internal thoracic artery preparation. METHODS: In group A (n = 57) the internal thoracic artery was dissected with the entire surrounding connective tissue after opening the pleura, using routine lateral pleural drainage. In group B (n = 55) a venoarterial pedicle was prepared without surrounding muscle leaving the pleura intact. We assessed blood loss, clinical outcome, lung function, location, intensity, and quality of pain 6 days and 3 months after the operation. RESULTS: Significantly higher blood loss was observed in group A (A, 608+/-58 mL; B, 470+/-48 mL; p = 0.027). Forced expiratory volume in 1 second was significantly decreased in group A 6 days after surgery (A, 76.0%+/-1.6%; B, 83.2%+/-1.6%; p = 0.020). The forced expiratory volume in 1 second correlated to inspiratory vital capacity, which confirmed the advantage of the venoarterial technique (A, 0.771+/-0.021; B, 0.832+/-0.020; p = 0.003). Vital capacity was significantly higher in the venoarterial group at 3 months (A, 85.2%+/-2.1%; B, 98.5%+/-1.2%; p = 0.009), but not on postoperative day 6. The incidence of pleural effusion and atelectasis was significantly higher in group A (effusion: A, 52.6%; B, 23.6%; p = 0.002; atelectasis: A, 42.1%; B, 20.0%, p = 0.015). Sternal pain (A, 36.8%; B, 9.1%; p = 0.001) and suspenders pain (A, 33.3%; B, 7.3%; p = 0.001) occurred more often in group A. When using a multidimensional pain score, patients in group A experienced significantly sharper (6 days: A, 6.7+/-0.3; B, 3.3+/-0.2; p = 0.018; 3 months: A, 3.5+/-0.3; B, 1.4+/-0.3; p = 0.046) and more annoying pain (6 days: A, 7.6+/-0.2; B, 2.7+/-0.1; p = 0.036; 3 months: A, 6.6+/-0.3; B, 2.3+/-0.2; p = 0.040). CONCLUSIONS: These results demonstrate that the venoarterial preparation technique is superior to conventional internal thoracic artery preparation regarding postoperative blood loss, lung function, and pain.

Female↗
PubMed1999

Synthetic protein treated versus heparin coated cardiopulmonary bypass surfaces: similar clinical results and minor biochemical differences.

OBJECTIVE: Complications associated with cardiopulmonary bypass (CPB) have gained more attention due to increased interest in coronary artery bypass grafting without CPB. The impact of heparin coating of CPB circuits has been discussed controversially. The present study examines if the treatment of the oxygenator surface with a synthetic protein may serve as an alternative to a completely heparin coated circuit. METHODS: Fifty-eight patients undergoing coronary artery bypass grafting with CPB were randomly assigned to completely heparin coated circuits or synthetic protein treated oxygenators in a double blind protocol, focussing on the inflammatory reaction resulting in membrane damage, coagulation changes and markers of cerebral injury or dysfunction. Treatment groups did not differ as to preoperative demographics, and intraoperative clinical data. Patients with any neurologic disease or risk factors for cerebral dysfunction were not included in the study. RESULTS: Postoperative clinical data did not differ between groups. Both surface treatments resulted in similar coagulation activation, hyperfibrinolysis and disseminated intravascular coagulation. Platelet count displayed a difference in favour of the heparin coated group (P = 0.029). Increased leukocyte activation reflected by rising myeloperoxidase concentrations on CPB was present in both synthetic protein and heparin coating groups. Interleukins 6 and 8 reacted similarly, but interleukin 8 increased significantly more (P = 0.0061) at the end of surgery in patients treated with protein treated oxygenators. The same pattern was observed for complement activation as determined by total complement complex (P = 0.006). Both surface changes resulted in moderately increased S-100B protein and neuron specific enolase, without difference between groups. Both markers did not reach concentrations associated with clinical manifestation of cerebral injury. CONCLUSIONS: These results in routine patients with short bypass time, imply that protein treated oxygenators are associated with a limited increase of biochemical markers similar to heparin coating. However, significantly lower interleukin 8 release and complement activation can be achieved by heparin coating. The protein treatment is a standard feature of the oxygenator examined in both groups. It is not associated with additional cost and therefore appropriate for use in routine patients.

Aged↗
PubMed1999

Valve-preserving treatment of Ebstein's anomaly: perioperative and follow-up results.

BACKGROUND: Ebstein's anomaly is a rare congenital cardiac defect of the tricuspid valve (TV) leading to severe tricuspid insufficiency (TI). METHODS: In ten patients, 6 adults (39-53 years) and 4 children (5-10 years), operated between 1989 and 1995 echocardiography was performed pre and post repair and at follow-up. Patients were assessed in our institution at two cut-off points, resulting in a mean first follow-up of 17 +/-15 months and a mean second follow-up of 53+/-23 months. All patients had additional congenital cardiac defects (ASD,VSD). In all patients the TV was repaired by techniques described by Carpentier et al. with some modifications. The goal of this reparative attempt is to mobilize restricted leaflet tissue and aid coaptation through implantation of a ring. RESULTS: Echocardiographically we were able to identify significant characteristics for the successful repair of Ebstein's anomaly. The severity of the disease is represented by the size and function of the right ventricle and the atrialized chamber, the most advanced cases exhibiting a dilated right ventricle with poor contractility. There was severe preoperative TI ( mean grade 3.2 +/- 0.3). Postoperatively TI was significantly reduced to a mean grade of 2+/-0.2. 60% of the patients demonstrated an improvement in the ratio of atrialized chamber to functional right ventricle. Right-ventricular function was improved, the mean score being 2.8+/-0.1. At follow-up I and II right-ventricular function and tricuspid insufficiency was improved in most patients and all patients benefited in quality of life. CONCLUSION: These results suggest that surgical correction should not be delayed until severe right heart failure develops as, particularly in children, good results are achieved, improving the quality of life.

Adult↗
PubMed1999

The bactericidal effect of Nd:YAG, Ho:YAG, and Er:YAG laser irradiation in the root canal: an in vitro comparison.

OBJECTIVE: The aim of this study was to compare the antibacterial effectiveness of the Nd:YAG, the Ho:YAG, and the Er:YAG laser in infected root canals. SUMMARY BACKGROUND DATA: Lasers are gaining increasing importance in the field of endodontics. Numerous studies have shown the beneficial effects of laser treatment in disinfecting root canals. METHODS: In our in vitro experimental setup, 40 extracted and endodontically treated teeth were inoculated with a suspension of Escherichia coli and Enterococcus faecalis and then irradiated at standardized power settings. The disinfecting efficacy of each laser was proved by classical microbiological examination. RESULTS: This article highlights that all three lasers substantially decreased the bacterial population with only minimal differences in their microbicidal efficacy. At 1.5 W, the best results were obtained by the Er:YAG laser achieving a mean bacterial elimination of 99.64%, followed by the Nd:YAG laser (99.16%), and the Ho:YAG laser (99.05%). CONCLUSION: Our findings indicate that all three lasers act as strongly effective microbicides without causing unfavorable temperature rises at the settings used. They can thus be considered a valuable tool for root canal treatment.

Dental Pulp Cavity↗
PubMed1999

Patient selection for Port-Access multi vessel revascularization.

Minimally invasive multivessel revascularization is rarely performed due to the difficult exposure of the aorta as well as the complete coronary anatomy through a small thoracotomy. The Port-Access technique bears additional contraindications for this procedure, which limits its potential as compared with other approaches to 'less invasive surgery'. Our aim was to show the applicability of this surgical technique to a wide range of patients with coronary artery disease. In our initial experience with this method (31 patients), the quality of anastomoses, graft patency, and clinical outcome are good, and do not differ from standard multivessel coronary artery bypass grafting. Port-Access multivessel revascularization can be performed safely and is appropriate for a large patient population.

Cardiac Catheterization↗
PubMed1999

Detection of canine distemper virus nucleoprotein RNA by reverse transcription-PCR using serum, whole blood, and cerebrospinal fluid from dogs with distemper.

Reverse transcription-PCR (RT-PCR) was used to detect canine distemper virus (CDV) nucleoprotein (NP) RNA in serum, whole blood, and cerebrospinal fluid (CSF) samples from 38 dogs with clinically suspected distemper. Results were correlated to clinical findings, anti-CDV neutralizing antibody titers, postmortem findings, and demonstration of CDV NP antigen by immunohistochemistry. The specificity of the RT-PCR was ensured by amplification of RNA from various laboratory CDV strains, restriction enzyme digestion, and Southern blot hybridization. In 29 of 38 dogs, CDV infection was confirmed by postmortem examination and immunohistochemistry. The animals displayed the catarrhal, systemic, and nervous forms of distemper. Seventeen samples (serum, whole blood, or CSF) from dogs with distemper were tested with three sets of primers targeted to different regions of the NP gene of the CDV Onderstepoort strain. Expected amplicons were observed in 82, 53, and 41% of the 17 samples, depending upon the primer pair used. With the most sensitive primer pair (primer pair I), CDV NP RNA was detected in 25 of 29 (86%) serum samples and 14 of 16 (88%) whole blood and CSF samples from dogs with distemper but not in body fluids from immunohistochemically negative dogs. Nucleotide sequence analysis of five RT-PCR amplicons from isolates from the field revealed few silent point mutations. These isolates exhibited greater homology to the Rockborn (97 to 99%) than to the Onderstepoort (95 to 96%) CDV strain. In summary, although the sensitivity of the RT-PCR for detection of CDV is strongly influenced by the location of the selected primers, this nucleic acid detection system represents a highly specific and sensitive method for the antemortem diagnosis of distemper in dogs, regardless of the form of distemper, humoral immune response, and viral antigen distribution.

Animals↗
PubMed1998

Blood rheology in patients with native heart valve disease and after valve replacement.

Patients with heart valve disease have rheologic abnormalities that are more pronounced in double valve disease than in mitral or aortic valve disease; after valve replacement surgery, the degree of rheologic abnormality is more pronounced in patients with mechanical and biological prostheses than in those with homografts and pulmonary autografts. Rheologic abnormalities seen in these patients might be related to the different incidences of thromboembolism in the presence of various valve defects and various types of prostheses.

Adolescent↗
PubMed1998

Effects of Nd:YAG-laser irradiation on monolayer cell cultures.

BACKGROUND AND OBJECTIVE: The clinical applications of Nd:YAG lasers on oral soft tissues include a wide field of surgical and periodontal procedures. This in vitro study focuses on the histological effects of Nd:YAG-laser irradiation on a fibroblast monolayer cell culture especially with regard to thermal damage and cell necrosis. The results of this basic research study provide us with clear power settings for a safe soft tissue laser treatment. STUDY DESIGN/MATERIALS AND METHODS: Two hundred forty multiwell cell cultures and 24 micro-slide Leighton tubes were laser treated. Laser irradiation was performed with a commercial free-running pulse Nd:YAG laser and a quartz fiber with a diameter of 200 microns on L-929 fibroblast cell cultures. The variable parameters were pulse energy (30-120 mJ), pulse rate (20-100 Hz), power output (1.5-3.0 W), and time of irradiation (10-60 s). The cultures were analyzed with help of vital staining, autoradiography, and cytomorphology examination. RESULTS: Depending on the different settings the laser irradiation caused inhibitions of the DNA metabolism rate and the cell division rate, a degeneratively changed cytomorphology up to cell pyknosis. An increasing pulse energy, pulse rate, or an increased time of irradiation created an extended diameter of the pyknotic cell zone. CONCLUSIONS: The laser beam creates an exactly bordered damage between cells. The cells had a very good inherent mobility, but the border between eliminated and unloaded cell zone was sharp, even after an incubation of 24 h. These stable results prove that the laser can be applied up to a micrometer distance. With the help of cell clusters it was proved that the laser beam is also able to eliminate exactly one monolayer. Cells which had been covered by another cell layer (in a cluster) were not eliminated.

Autoradiography↗
PubMed1998

Advantages of a pulsed CO2 laser in direct pulp capping: a long-term in vivo study.

BACKGROUND AND OBJECTIVE: A previous study [Moritz et al., Z Stomatol 1996; 93:451-454] had shown that favourable results in direct pulp capping could be achieved using a continuous wave CO2 laser in addition to the conventional calcium hydroxide dressing technique. In this study, these results are compared to those achieved using a CO2 laser working in superpulsed mode. STUDY DESIGN/MATERIALS AND METHODS: A total of 260 direct pulp capping procedures were carried out; 130 were performed with a superpulsed CO2 laser, followed by a calcium hydroxide dressing, and 130 conventionally by applying only a calcium hydroxide preparation. Recall examinations were performed after 1 week and monthly for 18 months after treatment. A final examination was carried out 2 years after treatment. Thermal tests were used for vitality assessments and laser Doppler flowmetry for direct measurement of pulpal blood flow. RESULTS: In the group of pulps treated with the superpulsed CO2 laser, the last recall examination at 2 years revealed that 93% of the teeth had remained vital. In the control group, the success rate was considerably lower (66.6%). Exposure site sizes and average patient age were nearly identical in both groups. CONCLUSION: The CO2 laser seems to be a valuable aid in direct pulp capping; the efficiency of laser treatment can be increased by using a pulsed CO2 laser.

Adolescent↗
PubMed1998

Treatment of periodontal pockets with a diode laser.

BACKGROUND AND OBJECTIVE: The aim of this study is to examine the long-term effect of diode laser therapy on periodontal pockets with regard to its bactericidal abilities and the improvement of periodontal condition. STUDY DESIGN/MATERIALS AND METHODS: Fifty patients were randomly subdivided into two groups (laser-group and control-group) and microbiologic samples were collected. There have been six appointments for 6 months following an exact treatment scheme. After evaluating periodontal indices (bleeding on probing, Quigley-Hein) including pocket depths and instruction of patients in oral hygiene and scaling therapy of all patients, the deepest pockets of each quadrant of the laser-group's patients were microbiologically examined. Afterwards, all teeth were treated with the diode laser. The control-group received the same treatment but instead of laser therapy were rinsed with H2O2. Each appointment also included a hygienic check-up. After 6 months the final values of the periodontal indices and further microbiologic samples were measured. The total bacterial count as well as specific bacteria, such as Actinobacillus actinomycetemcomitans, Prevotella intermedia, and Porphyromonas gingivalis, were assessed semiquantitatively. RESULTS: The bacterial reduction with diode laser therapy was significantly better than in the control group. The index of bleeding on probing improved in 96.9% in the laser-group, whereas only 66.7% in the control group. Pocket depths could be more reduced in the laser group than in the control group. CONCLUSION: The diode laser reveals a bactericidal effect and helps to reduce inflammation in the periodontal pockets in addition to scaling. The diode laser therapy, in combination with scaling, supports healing of the periodontal pockets through eliminating bacteria.

Aggregatibacter actinomycetemcomitans↗
PubMed1998

Long-term results of heart valve replacement with the Edwards Duromedics bileaflet prosthesis: a prospective ten-year clinical follow-up.

OBJECTIVE: The Edwards Duromedics valve (Baxter Healthcare Corp., Edwards Division, Santa Ana, Calif.) was designed with a self-irrigating hinge mechanism to reduce thromboembolic complications. After good initial clinical results, distribution was suspended in 1988 after reports of valve fracture after 20,000 valves had been implanted. The manufacturer conducted extensive studies to improve the Edwards Duromedics and reintroduced a modified version, which is available as Edwards Tekna. The purpose of the study was the evaluation of long-term results of the original Edwards Duromedics that might be important for the current version, the Edwards Tekna valve. METHODS: A prospective clinical 10-year follow-up was performed of 508 patients who underwent valve replacement with the Edwards Duromedics valve in the aortic (n = 268), mitral (n = 183), and aortic and mitral (n = 56) position. RESULTS: The perioperative mortality rate was 6.9%; follow-up was 98% complete, comprising 3648 patient-years for a mean follow-up of 86 months (range: 33 to 144 months). The actuarial freedom from complications at the 10-year follow-up and the incidence rate (percent per patient-year) were as follows: late mortality rate, 69.2% +/- 2.4% (3.5% per patient-year); thromboembolism, 90.7% +/- 1.6% (0.96% per patient-year); anticoagulation-related hemorrhage, 87.7% +/- 1.7% (1.34% per patient-year); prosthetic valve endocarditis, 96.7% +/- 0.09% (0.38% per patient-year); valve-related mortality rate, 89.3% +/- 1.6% (1.21% per patient-year); valve failure, 86.2% +/- 1.85% (1.54% per patient-year); and valve-related morbidity and mortality rate, 71.1% +/- 2.3% (3.2% per patient-year). Three leaflet escapes were observed (one lethal, two successful reoperations; 99.1% +/- 0.05% freedom, 0.08% per patient-year). All patients functionally improved (86% in New York Heart Association classes I and II), and incidence of anemia was insignificant. CONCLUSIONS: These results confirm that the Edwards Duromedics valve shows excellent performance concerning thromboembolism, hemolysis, and functional improvement and will serve as a reference for the last version, the Edwards Tekna valve, where comparable long-term data are currently not available.

Anticoagulants↗
PubMed1998

The CO2 laser as an aid in direct pulp capping.

Two hundred direct pulp capping procedures were conducted in the present study. One hundred of them were performed with the CO2 laser, and 100 were conducted conventionally as a control by using a calcium hydroxide preparation. Follow-up examinations were performed after 1 wk and monthly for 12 months after treatment. Thermal tests were used for vitality assessments and laser Doppler flowmetry for direct measurement of pulpal blood. In the group of pulps treated with the CO2 laser, the last recall examination at 12 months demonstrated that 89 teeth remained vital, corresponding to a success rate of 89%. In the control group, the success rate was considerably lower (68%). Exposure sizes and mean patient age were nearly identical in both groups. The CO2 laser seems to be a valuable aid in direct pulp capping.

Adolescent↗
PubMed1998

Association of a human G-protein beta3 subunit variant with hypertension.

Hypertension is a common disorder of multifactorial origin that constitutes a major risk factor for cardiovascular events such as stroke and myocardial infarction. Previous studies demonstrated an enhanced signal transduction via pertussis toxin-sensitive G proteins in lymphoblasts and fibroblasts from selected patients with essential hypertension. We have detected a novel polymorphism (C825T) in exon 10 of the gene encoding the beta3 subunit of heterotrimeric G proteins (GNB3). The T allele is associated with the occurrence of a splice variant, GNB3-s (encoding G beta3-s), in which the nucleotides 498-620 of exon 9 are deleted. This in-frame deletion causes the loss of 41 amino acids and one WD repeat domain of the G beta subunit. By western-blot analysis, G beta3-s appears to be predominantly expressed in cells from individuals carrying the T allele. Significant enhancement of stimulated GTPgammaS binding to Sf9 insect cells expressing G beta3-s together with G alpha(i)2 and G gamma5 indicates that this splice variant is biologically active. Genotype analysis of 427 normotensive and 426 hypertensive subjects suggests a significant association of the T allele with essential hypertension.

Alleles↗
PubMed1998

Reversal of ventricular dilatation after correction of aortic incompetence: mechanical prosthesis compared with biological procedures.

BACKGROUND: The aim of the study was to compare early differences in reversal of LV dilatation between patients with mechanical prosthesis = group A (n = 51: Carbomedics = 40, Tekna/Edwards = 11) and biological procedures = group B (n = 75: pulmonary autograft = 36, aortic valve repair = 29, homograft = 10). METHODS: Since 1,990,126 consecutive patients younger than 50 years who had surgical correction of isolated aortic incompetence underwent echocardiographic examinations preoperatively, at discharge, and at one-year follow-up. Left-ventricular (LV) diameters were measured (LVEDD, LVESD) and matched to body surface area (LVESDI, LVEDDI and fractional shortening (FS) was calculated. Aortic peak flow velocities were assessed by Doppler technique and gradients were calculated. RESULTS: There were no significant differences preoperatively in aortic incompetence, NYHA classification, LVEDDI, LVESDI, and FS. In group B there was a significant decrease of LVESDI (p < 0.002) and LVEDDI (p < 0.001) but no change in FS at discharge. In group A a significant reduction of FS (p < 0.05) without any significant changes in LV size was observed. No patient died perioperatively or during the first year. At one-year follow-up (complete in 97.6% patients) there were no significant differences in LV diameters but group B had better ventricular function (p < 0.05) resulting in better NYHA classification (p < 0.05). Only group B had normal aortic valve gradients at discharge and at follow-up (A: 25.2 +/- 4.3 vs B: 10.2 +/- 2.4 mmHg). CONCLUSIONS: Normal aortic valve gradients in patients after aortic valve repair or allograft replacement for chronic aortic incompetence lead to early recovery from ventricular dilatation and significantly better ventricular function at discharge. One year postoperatively they had improved ventricular function and NYHA class in comparison with patients in whom a mechanical prosthesis was implanted.

Adult↗