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M Grimm

Publications and source records attributed to M Grimm.

At least 55 records · Page 3Linked to original sources
PubMed2001

Three-dimensional visualization of coronary arteries in excised hearts.

OBJECTIVE: We sought to image coronary arteries in excised hearts. METHODS: Twelve excised pigs' hearts were imaged in a water bath. The aortic valve was closed surgically. A contrast agent (Echovist) was injected into the aortic root and selectively into single coronary arteries. Three-dimensional (3D) imaging was performed with TomTec Echoscan equipment. Mechanical rotations were performed at 1 degrees intervals. The hearts were visualized by InVivo software. Selective coloring of coronary arteries in 3D data sets was obtained by using color superpositioning, which differentiates information before and after injection of contrast. Distance measurements were performed in conventional 3D echocardiograms of coronary arteries and color-superimposed echocardiograms and compared with those from angiograms and casts. RESULTS: After a learning curve, during which optimal conditions for the visualization of coronary arteries were determined, a quick display of all major parts of the coronary tree was obtained. Distance measurements (n >400) revealed that fundamental contrast echocardiography overestimated angiography by 25% +/- 5% and casts by 28% +/- 6%. However, distances in color-superimposed echocardiograms (flow mode 4) were not significantly different from those obtained from angiograms and casts. In harmonic contrast echocardiograms, color super-positioning gave smaller distances compared with those from fundamental contrast echocardiograms, though they were still significantly larger than the reference diameters. CONCLUSIONS: The 3D imaging of epicardial coronary arteries under ideal conditions in a water bath seems feasible and provides insight into coronary visualization with the use of ultrasonography.

Animals↗
PubMed2001

24h variation in the expression of the mt1 melatonin receptor subtype in coronary arteries derived from patients with coronary heart disease.

Previous studies presented evidence for impaired nocturnal secretion and synthesis of melatonin in patients with coronary heart disease (CHD). This study aimed to investigate whether the melatonin receptor subtype mt1 is differentially expressed in coronary arteries derived from patients with CHD (n = 9) compared to patients with dilative cardiomyopathy (CMP; n = 10) who served as controls. Expression of the mt1 receptor was studied in sections of isolated coronary arteries by a reverse transcriptase-polymerase chain reaction (RT-PCR) and a Western immunoblot technique. In addition, the data from the Western blotting of 15 patients were interpolated against the exact time of aortic clamp to study the 24h expression of the mt1 receptor. The analyses of the results from both methods indicated the presence of the mt1 receptor in all of the individuals. No statistically significant difference was observed in the receptor expression between patients with CHD and those with CMP (in arbitrary units: 3.39 +/- 3.08 versus 3.91 +/- 2.78). Expression of the melatonin receptor in the coronary arteries of the whole patient group presented a 24h variation, with the lowest values detectable after 02:00 up to the late morning hours and a progressive increase beginning after 13:00 until 00:00 (mesor = 3.66, amplitude = 3.23, acrophase = 20.45, P = .0003). When studying the 24h variation in patients with CHD and CMP separately, a nearly similar circadian course was observed. In conclusion, we demonstrated for the first time a 24h variation of a melatonin receptor subtype in human vessels. Furthermore, in relation to our results, we suggest that the expression of the mt1 melatonin receptor in the coronary arteries is probably not impaired in patients with CHD.

Adult↗
PubMed2001

Expression of the MT1 melatonin receptor subtype in human coronary arteries.

Previous experimental data suggest a possible influence of melatonin on the circulatory system of animals after binding to G-protein coupled melatonin receptors. The present study sought to investigate whether the melatonin receptor, mt1, is expressed in human coronary arteries derived from healthy heart donors (n = 8). Expression of the mt1-receptor was studied in sections of isolated coronary arteries by a reverse transcriptase-polymerase chain reaction (RT-PCR) and Western immunoblot technique. The analyses of the results from both methods indicated the presence of the mt1-receptor in all of the subjects. Referring to these data we assume that melatonin regulates physiological processes in human coronary arteries after receptor binding.

Base Sequence↗
PubMed2001

Presynaptic regulation of cardiac norepinephrine release in ischemia.

In myocardial ischemia presynaptic regulation of norepinephrine release may be altered either by ischemic effects on presynaptic receptor signaling or by ischemia-evoked accumulation of endogenous agonists. Because presynaptic receptors are targets of several drugs. such alterations may have pharmacotherapeutic implications. We investigated the effect of brief ischemic periods on presynaptic regulation of norepinephrine release by alpha2-adrenoceptors, beta2-adrenoceptors, adenosine A1-, angiotensin AT1-, and bradykinin B2-receptors in isolated perfused rat hearts. Exocytotic norepinephrine release was evoked by electrical field stimulation. Paired stimulations were performed to compare the pharmacologic intervention (S2) with the release under baseline conditions (S1), and the effects of receptor agonists and antagonists were compared under nonischemic and stop-flow conditions. In summary. during brief myocardial ischemia, presynaptic modulation of norepinephrine release is differentially regulated. Autoinhibitory alpha2-adrenoceptors lose their activity, whereas stimulatory beta2-adrenoceptors are sensitized. Inhibitory adenosine A1-receptors gain importance during ischemia owing to endogenous adenosine formation. Bradykinin- and angiotensin-mediated stimulation of norepinephrine release is not affected under ischemic conditions.

Adrenergic alpha-2 Receptor Agonists↗
PubMed2001

Statins as antioxidant therapy for preventing cardiac myocyte hypertrophy.

Cardiac hypertrophy is a major cause of morbidity and mortality worldwide. The hypertrophic process is mediated, in part, by small G proteins of the Rho family. We hypothesized that statins, inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase, inhibit cardiac hypertrophy by blocking Rho isoprenylation. We treated neonatal rat cardiac myocytes with angiotensin II (AngII) with and without simvastatin (Sim) and found that Sim decreased AngII-induced protein content, [3H] leucine uptake, and atrial natriuretic factor (ANF) promoter activity. These effects were associated with decreases in cell size, membrane Rho activity, superoxide anion (O2*-) production, and intracellular oxidation, and were reversed with L-mevalonate or geranylgeranylpyrophosphate, but not with farnesylpyrophosphate or cholesterol. Treatments with the Rho inhibitor C3 exotoxin and with cell-permeable superoxide dismutase also decreased AngII-induced O2*- production and myocyte hypertrophy. Overexpression of the dominant-negative Rho mutant N17Rac1 completely inhibited AngII-induced intracellular oxidation and ANF promoter activity, while N19RhoA partially inhibited it, and N17Cdc42 had no effect. Indeed, Sim inhibited cardiac hypertrophy and decreased myocardial Rac1 activity and O2*- production in rats treated with AngII infusion or subjected to transaortic constriction. These findings suggest that statins prevent the development of cardiac hypertrophy through an antioxidant mechanism involving inhibition of Rac1.

Angiotensin II↗
PubMed2001

Methotrexate in the management of immune mediated cochleovesitibular disorders: clinical experience with 53 patients.

OBJECTIVE: To describe our experience with low dose weekly methotrexate (MTX) in the management of immune mediated cochleovestibular disorder (IMCVD). METHODS: Between 1991 and 1999, we treated 53 patients with IMCVD with MTX. Patients were selected on the basis of progressive vestibular symptoms that had responded to corticosteroids and in most cases, relapsed. MTX was initiated at a dose of 7.5 mg weekly and increased to doses up to 25 mg weekly as needed. Response was assessed by audiologic studies and history of change in tinnitus and vertigo. MTX was discontinued after 4-6 mo in patients showing no improvement, and after 12-18 mo in patients with improved and stable symptoms. RESULTS: Three patients were still in early therapy and had not improved. Of the 50 remaining patients, significant improvement was seen in vertigo in 27/39 (69%) patients, hearing loss in 25/47 (53%), and tinnitus in 11/42 (26%). Overall improvement in symptoms was seen in 35/50 (70%) patients. Four patients stopped MTX due to toxicity, and 11 due to lack of response. In 28 patients, MTX was stopped after 12-18 mo when symptoms had stabilized, and restarted in 5 of these after relapse. Seven patients remain on therapy with improved and stable symptoms after 17.3 mo. CONCLUSION: In this open label experience, a majority of patients with IMCVD improved with weekly low dose MTX therapy with minimal toxicity.

Adolescent↗
PubMed2000

Inter- and intra-individual variation of faecal water - genotoxicity in human colon cells.

Exogenous nutritional factors modulate the faecal contents leading to an enhanced or reduced burden with toxic and cancerogenic factors. These factors are thought to contribute to colon cancer by inducing mutations or enhancing proliferation in colon cells. Faecal water more or less causes these effects in model systems and thus could be the basis for valuable biomarker approaches. Our investigations are aimed at determining geno- and cytotoxicity of faecal water in human colon cell lines in vitro. We are developing techniques for their applicability as biomarker tests during dietary intervention studies. Faecal water is isolated by centrifugation of the faeces at 25000xg and added to cultured human colon cells (HT29). Membrane damage as assessed by trypan blue exclusion is determined as a measure for cytotoxicity. Semiquantitative analysis of inducible DNA damage (breaks and alkali labile sites) are analysed with the single cell microgelelectrophoresis assay (comet-assay) and oxidised DNA bases by the additional use of repair specific enzymes. We have now determined baseline toxic activities and calculated inter- and intra-individual and -experimental coefficients of variation for faecal water from different subjects consuming similar or different diets. Most faecal water induced DNA damage and oxidised DNA bases in HT29 clone 19a cells (0.9-9.14 fold and 1.7-4.9 fold, respectively in comparison to the NaCl controls). Intra- and inter-experimental coefficients (CV) of variation, were in a similar order of magnitude and ranged from 6.9 to 31.4. In contrast both intra- and inter-individual variability were considerably higher (CV-ranges of 29.7-76.6 and 21.3-64.0, respectively). Interestingly, these inter-individual values were not lowered when subjects consumed identical diets (CV-ranges of 28.4-126.0). However, following intervention with certain protective dietary regimens (e.g. lignan containing bread) significant reductions of faecal water-induced genotoxicity can be observed. Therefore, in spite of the expected and observed degrees of variation in this methodology, effective experimental protocols may still lead to detectable modulations of the level of toxic and genotoxic effects.

Adult↗
PubMed2000

Improved long-term results with thymoglobuline induction therapy after cardiac transplantation: a comparison of two different rabbit-antithymocyte globulines.

BACKGROUND: The aim of this retrospective single center analysis was to compare possible long-term benefits of two different rabbit-antithymocyte globuline (ATG) induction therapies after cardiac transplantation. PATIENTS AND METHODS: A total of 484 primary cardiac transplanted patients received induction therapy with two different rabbit-ATGs (thymoglobuline: n=342, ATG-fresenius: n=142). All patients received immunosuppressive maintenance therapy with cyclosporine, azathioprine, and prednisolone. Cardiac rejection was assessed by serial endomyocardial biopsies. Surveillance of graft arteriosclerosis was performed by angiograms 1, 3, and 5 years after transplantation. RESULTS: Five-year survival was significantly better in the thymoglobuline group (76 vs. 60%). Thymoglobuline patients had a lower rate of death from rejection (2.3 vs. 10%; P<0.01) and graft arteriosclerosis (0.88 vs. 5.6%; P<0.01). After 5 years, freedom from rejection was 72% in the thymoglobuline group compared to 42% in the ATG-fresenius group (P<0.01). Graft arteriosclerosis appeared in 14% of thymoglobuline patients and in 28% of ATG-fresenius patients (P<0.01). Viral infections occurred more often in thymoglobuline patients (53 vs. 39%, P<0.05) although there was no difference in appearance of cytomegalovirus disease (17 vs. 13%). Freedom from posttransplant malignant disease was comparable between the two groups. CONCLUSION: These results suggest that there are differences between rabbit ATG products. The superior prevention of rejection with thymoglobuline may be the reason for the lower rate of graft arteriosclerosis.

Adolescent↗
PubMed2000

[Free hand acquisition, reconstruction and visualization of 3D and 4D ultrasound].

3D Ultrasound will find in the next years a wide popularity under the medical imaging applications. The method expands the well-known sonography on the third dimension, therefore it becomes possible to generate spatial 3D views of internal organs. It is further possible to display static (3D) as well as dynamic organs (4D, e.g. pulsating heart). The clarity of the three-dimensional presentation supports very effectively the navigation. In this article we review the upgrading of conventional ultrasound devices on 3D and 4D capabilities, as well as the display of the datasets by corresponding visualisation and filtering approaches.

Computer Graphics↗
PubMed2000

Pre- and early postoperative risk factors for death after cardiac transplantation: a single center analysis.

Due to the limited number of donor organs, death on the waiting list and waiting time for cardiac transplantation have markedly increased. A pressing need of appropriate selection criteria for patients who would benefit most from transplantation is apparent. The purpose of this study is to identify pre- and early postoperative risk factors that influence long term survival after cardiac transplantation. 702 consecutive patients who underwent cardiac transplantation between 3/1984 and 12/1997 were analyzed retrospectively for the influence of different pre- and early postoperative risk factors on early (30 days) and late death (5 years). Univariate and multivariate regression analysis revealed risk factors for early as well as late death. Predictors of early death were higher preoperative PVR, retransplantation, longer ischemic time, postoperative acute kidney failure and longer intubation time. Risk factors for late death were early transplant era, previous cardiac surgery, patients awaiting transplantation in a hospital, prolonged stay in an intensive care unit, and any rejection during the first month after transplantation. These results demonstrate that pre- and early postoperative risk factors have significant influence on early and long term survival.

Adolescent↗
PubMed2000

Right ventricle lipoma with pseudoaneurysmatic appearance.

The case of a 78-year-old female patient, with a large lipoma (13 x 17 x 10 cm) of the right ventricle, appearing pseudoaneurysmatic, is presented. Radical resection left a considerable right ventricle wall and interventricular septum defect which was reconstructed with a bovine pericardium patch.

Aged↗
PubMed2000

Prostaglandin E(1) does not influence plasmatic coagulation, hepatic synthesis, or postoperative blood loss in patients after coronary-artery bypass grafting.

STUDY OBJECTIVE: To assess whether postoperatively administered prostaglandin E1 (PGE1) might prevent bleeding in patients after coronary artery bypass grafting (CABG). DESIGN: Prospective, randomized, placebo-controlled trial. SETTING: University-affiliated hospital. PATIENTS: 49 patients scheduled for elective CABG surgery. INTERVENTIONS: The PGE1 group received intravenous PGE(1) up to 15 ng/kg/min for 72 hours after surgery, whereas the placebo group received isotonic saline for the same time period. MEASUREMENTS AND MAIN RESULTS: Nine patients (4 in the PGE1 group vs. 5 in the placebo group) had to be excluded because of hemodynamic instability, and 1 in the placebo group because of gastric bleeding. In the remaining 39 patients (20 vs. 19), no significant differences with regard to hemoglobin levels or platelet count could be observed. There was no significant difference between the groups concerning the amount of packed red blood cells, platelet concentrates, or fresh frozen plasma transfused. No significant differences could be observed regarding laboratory markers of coagulation activation or hepatic synthesis either. CONCLUSIONS: PGE1 did not prevent coagulation disturbances and blood loss when administered postoperatively in patients undergoing CABG. The absence of these expected effects might be explained by the concomitant administration of acetylsalicylic acid, whose antiaggregatory acivity seems to exceed the effects of PGE1.

Aged↗