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Biomedical subjects

M Kamler

Publications and source records attributed to M Kamler.

At least 19 recordsLinked to original sources
PubMed2005

Heart transplantation and consecutive mitral valve replacement.

A 48-year-old man was diagnosed with progressive mitral insufficiency due to fibrosis of papillary muscles and chordae tendineae, necessitating mitral valve replacement (MVR) 8 months after cardiac transplantation. Donor echocardiography and inspection of the heart at procurement were inconspicuous. The patient is alive, free from valve-related complications and functionally improved six years after MVR. The limited yet successful experiences with left-sided valve repair or replacement in the transplanted heart are reviewed.

Cardiomyopathy, Dilated↗
PubMed2005

Immunohistochemical differentiation of eosinophilic heart diseases using antibodies against eosinophil activation markers.

AIMS: Eosinophilic heart syndromes are rare in Western countries and include endocarditis parietalis fibroplastica (EPF) and hypersensitivity myocarditis (HM). There are striking differences in natural history and morphological findings. Since diagnosis can be difficult when analysing small myocardial biopsies lacking the characteristic histological features, we studied a set of immunohistochemical markers in order to characterize the activation status of the infiltrating eosinophils to distinguish between these two entities. METHODS AND RESULTS: This study is based on the investigation of seven explanted hearts and one left ventricular specimen collected during implantation of a left ventricular assist device from a total of seven patients with HM. Also investigated were three right and three left ventricular specimens from five patients with EPF. We used antibodies (Ab) against EG1, and EG2, CD44, and CD69 which have been described as markers to distinguish between resting and activated eosinophils. The EG1 to EG2 ratio of eosinophils and the immunoreactivity against CD44 showed no differences between the two entities. However, eosinophils in the EPF were completely negative for CD69, whereas eosinophils reacted positively within the HM group. CONCLUSION: The immunohistochemical investigation of eosinophilic heart diseases using antibodies against CD69 can be a useful tool to distinguish between hypersensitivity myocarditis and endocarditis parietalis fibroplastica.

Aged↗
PubMed2004

Deleterious effects of oxygen during extracorporeal circulation for the microcirculation in vivo.

OBJECTIVE: Clinical complications arising from extracorporeal circulation (ECC) have been linked to disturbances in the microcirculation. Hyperoxia, a mainstay of supportive treatment, is clinically used for a variety of pathological states. In previous in vivo animal experiments we found increased leukocyte/endothelial (L/E) cell interaction following ECC due to oxygen derived free radicals. This study was carried out to investigate the link between arterial pO2 during ECC and the potential damage to the microcirculation, supposedly caused by oxygen derived radicals. METHODS: Intravital fluorescence microscopy was used on the dorsal skinfold chamber preparation in syrian golden hamsters. ECC was introduced via a micro-rollerpump (0.7 ml/min) and a 60 cm silicon tube (1 mm inner diameter) shunted between the carotid artery and the jugular vein after application of 300 IE Heparin/kg/bw. Experiments were performed in chronically instrumented, awake animals (age: 10-14 weeks, weight: 65-75 g). Control inspired room air, experimental group 1 inspired 100% oxygen, group 2 received 100% oxygen and 2000 IE of Heparin i.v. (n=7/group), that releases endothelial bound superoxide dismutase, a natural scavenger of oxygen derived free radicals in the hamster. RESULTS: Normobaric inhalation of 100% oxygen increased arterial pO2 from 64+/-8.1 mmHg to 512+/-124 mmHg (P<0.05 vs. baseline). ECC under 100% oxygen reduced functional capillary density (FCD) to 70% of baseline values 8 h after ECC (P<0.05). Adherent leukocytes in postcapillary venules and arterioles increased significantly (P<0.05). 2000 IE Heparin prevented the reduction in FCD and decreased the number of adherent leukocytes. CONCLUSIONS: Reduction in FCD, increased leukocyte adherence to the microvascular endothelium of postcapillary venules and arterioles under hyperoxia compared to ECC under room air conditions, demonstrates harmful effects of oxygen during ECC in vivo. A high dose of Heparin enhances functional capillary density, thus attenuating the microvascular dysfunction/damage in the period after ECC.

Animals↗
PubMed2004

Severe left ventricular failure after double lung transplantation: pathophysiology and management.

Patients undergoing bilateral lung transplantation for end-stage pulmonary hypertension may experience various complications. We describe a patient who underwent transplantation for chronic pigeon breeder's disease, who had secondary pulmonary hypertension and deteriorated right heart function, and who developed severe left heart failure during the weaning phase after successful double lung transplantation. The patient was stabilized with catecholamines and an intra-aortic balloon pump. Left heart function increased within 7 days and normalized at Day 18. Otherwise, the post-operative course was uneventful.

Bird Fancier's Lung↗
PubMed2004

Long-term occurrence of Hemolivia cf. mauritanica (Apicomplexa: Adeleina: Haemogregarinidae) in captive Testudo marginata (Reptilia: Testudinidae): evidence for cyclic merogony?

Blood smears from wild-caught, long-term captive tortoises, Testudo marginata, revealed the presence of gametocytes of a Hemolivia mauritanica-like hemogregarine in the erythrocytes of 72% tortoises examined. Significant parasitemia was also found in animals living several years in captivity. Experimentally infected tortoises showed no evidence of a decrease in parasitemia level more than 15 mo after infection. Morphologically, stages found in tortoises' erythrocytes were indistinguishable from those referred to by previous workers as H. mauritanica from Testudo graeca. Moreover, successful experimental transmission to Hyalomma aegyptium confirms the conspecificity with H. mauritanica. The occurrence of H. mauritanica gametocytes in tortoise living up to 8 yr in captivity is suggested to result from continuous, long-lasting cyclic merogony in tortoises' parenchymatous organs, which is an unknown phenomenon in the life cycle of Hemolivia spp.

Animals↗
PubMed2003

[A "late" scimitar syndrome. Diagnostic contribution of cardiac computed tomography].

A 51-year-old female hospitalized with a non-specific colitis, presented a crescent-like shadow in the right lower lung accompanied by a reduced right lung volume on a routine chest x-ray. There was no family history of congenital heart disease. The initially performed, noninvasive, contrast enhanced cardiac CT (electron-beam tomography [EBT]) proved the suspected diagnosis of a partial, anomalous pulmonary, transdiaphragmatic vein drainage (APVD) in combination with a hypoplastic right lower lobe and dextrocardia. These findings are in accordance with scimitar syndrome. Regarding to the clinical situation with symptoms like slowly progressive dyspnea on exertion and low exercise tolerance for the last 2 years and an invasively documented left-to-right shunt ratio >50% (Qp:Qs = 2.6 : 1) surgical repair was recommended. The anomalous vein was connected to the left atrium creating a "neo-septum". On a postoperative checkup after 9 months the patient is without any medication, symptoms during moderate activity are relieved, exercise tolerance was substantially better and noninvasive imaging visualized the corrected drainage of the anomalous vein to the left atrium.

Anastomosis, Surgical↗
PubMed2001

[Surgical treatment of infective endocarditis: the Essen experiences].

BACKGROUND: Instead of immediate diagnosis and effective antibiotic treatment morbidity and mortality in infective endocarditis remains high. If the infection cannot be controlled or the disease progresses irreversible destruction of cardiac structures results. SURGICAL THERAPY: In this case surgical therapy should be considered immediately. The outcome of surgical repair is not depending on the implanted prosthesis, but solely on timing of the operation.

Acute Disease↗
PubMed2001

Hirudin protects from leukocyte/endothelial cell interaction induced by extracorporeal circulation.

BACKGROUND: The clinical complications of Extracorporeal Circulation (ECC) have been linked to disturbances in the microcirculation. In order to prevent these deleterious effects, a biodegradeable agent to coat the extracorporeal circuit was tested. METHODS: Intravital fluorescence microscopy was used on the hamster skinfold chamber model in permanently instrumented, awake animals. ECC was introduced via a micro-roller-pump and a silicon tube shunted between the carotid artery and the jugular vein. The ECC-tube system was coated with PEG-Hirudin-Iloprost, two additional groups received either Iloprost i.v. (0.8 mg/kg/h) or Hirudin i.v. (1 mg/kg b.w.). RESULTS: ECC for 20 minutes resulted in an increase in rolling and adherent leukocytes in postcapillary venules (Roller 9 to 36 [%]; Sticker 24 to 330 [n/mm2]). Use of the coated tube system reduced L/E cell interaction (Roller 9 to 24* [%], Sticker 28 to 194* [n/mm2]; *p<0.05), whereas Hirudin i.v. nearly abolished it. CONCLUSIONS: The protective effects of the coating and of Hirudin i.v are probably a result of an attenuated activation of the coagulation-fibrinolytic system.

Animals↗
PubMed2001

Near-fatal hemoptysis and emergency surgical repair after aortic patch-plasty.

A 38-year-old man presented with massive hemoptysis followed by hemorrhage shock. The patient's history revealed a Dacron patch repair for aortic coarctation and recoarctation carried out twice, once 23 and once 10 years ago. Diagnosis of a ruptured descending aortic aneurysm with an aortobronchial fistula into the left lower lobe was established using CT scan. Emergency surgery consisted of left pneumonectomy and descending aortic graft replacement during deep hypothermic circulatory arrest. The patient was discharged 12 days later.

Adult↗
PubMed2000

Sepsis and catecholamine support are the major risk factors for critical illness polyneuropathy after open heart surgery'.

BACKGROUND: Critical illness polyneuropathy (CIP) remains a problem after open heart surgery. Recently, we reported about a retrospectively performed study pointing out that sepsis, the application of higher amounts of catecholamines and intervention such as chronic venovenous hemodiafiltration may be involved in the onset of CIP. A prospectively performed study is presented in order to evaluate the significance of risk factors initially after open heart surgery. METHODS: From June 1997 until September 1998, patients undergoing open heart surgery and being ventilated beyond 3 days were prospectively enrolled in the study and underwent a standard protocol of electromyographic investigation in order to determine CIP. Several items were recorded: amount of catecholamines, serum levels of urea, creatinine, albumin, and glucose. The duration of sepsis and chronic venovenous hemodiafiltration were reevaluated. Additionally the age, the left ventricular end-diastolic pressure prior to the operation, the time of ICU stay and the time of ventilatory support were compared. RESULTS: Within the observation period, 37 adult patients could be enrolled in the study, whereas 12 patients did develop CIP and 7 patients did not. Patients developing CIP required significantly different amounts of epinephrine (0.17 +/- 0.02 vs. 0.09 +/- 0.01 mg/kg/day, p < 0.05, t-test) higher amounts of norepinephrine (0.06 +/- 0.02 vs. 0.02 +/- 0.01 mg/kg/day, p<0.05, t-test), and lesser dosages of dobutamine (2.2 +/- 0.5 vs. 4.9 +/- 0.7, p<0.05, t-test). After cardiac surgery, the plasma levels of urea was initially significantly elevated in patients developing CIP (127.4 +/- 10.5 vs 97.3 +/- 18.5, p<0.05, t-test) Patients suffering from CIP stayed significantly longer in the ICU (40.3 +/- 11.7 vs. 19.6 +/- 11.3 days, p < 0.05 t-test) with an extended time of ventilator support. (769.6 +/- 05.0 vs 295.0 +/- 134.0 hours, p<0.05, t-test). Patients of the CIP group were suffering significant longer from sepsis than patients without CIP. CONCLUSIONS: Sepsis and catecholamine support and an increased level of urea were associated with the development of CIP. The prevention of sepsis and a modulation of the catecholamine support in order to improve microcirculatory flow may reduce the onset of CIP in patients undergoing open heart surgery.

Aged↗
PubMed1998

Interruption of bronchial circulation leads to a severe decrease in peribronchial oxygen tension in standard lung transplantation technique.

OBJECTIVE: In clinical practice lung transplantation is the only procedure where the transplanted organ is left without its own arterial perfusion. With the interruption of the bronchial arteries the nutritive support is dependent on collateral flow by the pulmonary artery and the oxygen tension of desaturated central venous blood, representing an abnormal physiology. METHODS: To analyze this problem systematically, we used a standard single left lung transplantation model in the pig (n = 12). In accordance with the clinical standard, lung preservation was performed with modified Euro-Collins solution with addition of prostacycline. The duration of ischemia was set to 4 h. Before and after single left lung transplantation tissue oxygen tension in the peribronchial tissue was measured with Licox tissue pO2 microprobes. For validation, the myocardial tissue oxygen tension was recorded simultaneously. The hemodynamic assessment included continuous flow measurement of the left and right pulmonary artery using Transsonic ultrasound flow probes. After transplantation the animals were observed for 4 h. For hypothetic augmentation of collateral blood flow to the peribronchial tissue we administered Nitric oxide (10 ppm) to the ventilation in six pigs (group B). Six pigs (group A) served as a control without the addition of nitric oxide (NO). All pigs were ventilated with a FiO2 of 0.5 resulting in paO2 values between 160 and 200 mmHg. RESULTS: In both groups single lung transplantation led to a significant decrease in peribronchial tissue oxygen tension throughout the observation period. Pre-Tx values of peribronchial tissue oxygen tension (38.31 +/- 6.56 mmHg) decreased to 9.72 +/- 2.55 mmHg in group A and 10.3 +/- 3.61 mmHg in group B after 4 h, which could not be altered by a FiO2 of 1.0 (P < 0.0001). The addition of NO in group B led to a significantly augmented flow in the left pulmonary artery (0.63 +/- 0.31 l/min in group B vs. 0.46 +/- 0.26 l/min group A, P < 0.001) representing 67 vs. 49% of the pre-Tx flow in groups B and A, respectively, but the peribronchial tissue oxygen tension was not influenced (P > 0.05). In both groups A and B, the central venous pO2 did not differ in the postoperative period (41.83 +/- 3.27 mmHg group A vs. 43.26 +/- 2.98 mmHg group B) and was kept in a comparable range to the pretransplantation values (45.23 +/- 3.41 mmHg pre-Tx). CONCLUSIONS: The persistence of a very low peribronchial tissue oxygen tension in the early phase after lung transplantation cannot be influenced by improved pulmonary artery flow and solely relates to the central venous pO2, which cannot be augmented by the addition of NO. This mechanism might be a trigger for anastomotic healing problems, infectious complications and later development of obliterative bronchiolitis (OB).

Animals↗
PubMed1997

[Alpha 2-adrenergic agonists. Use in chronic pain--a meta-analysis].

alpha(2)-adrenergic agonists, mimicking the action of the inhibitory transmitter norepinephrine, cause antinociception due to postsynaptic inhibition of spinothalamic projection neurons, presynaptic inhibition at the central nervous system termination of primary sensory nerves, presynaptic inhibition of brainstem noradrenergic neurons and a generalized decrease in central nervous system sympathetic efferent activity. There is a mutual potentiation of antinociceptive effects of clonidine and morphine. Clonidine is used in chronic pain states for treatment of neuropathic, neuralgic and deafferentiating pain. Based on a meta-analysis of the studies published in the years 1996-1996, the therapeutic efficacy of systematically administered clonidine was evaluated in chronic pain states. Out of 403 screened published studies, only 9 fulfilled the selection criteria. Besides three case reports with successful clonidine treatment, four placebo-controlled studies could be analyzed treating the following chronic pain states: chest pain despite normal coronary angiograms; painful diabetic neuropathy; postherpetic neuralgia; hyperalgia in patients with sympathetically maintained pain and chronic low back pain. Although three studies demonstrated statistically significant improvement in pain scores, the improvement in pain relief in these cases was slight. Long-term treatment was successful in a few responders over a period of 17 months. Hyperalgesia caused by sympathetically maintained pain was relieved by topical (transdermal) application of clonidine. Based on this evaluation a grade C recommendation is derived, which relates to responders. Successful treatment is expected only in pain states with increased sympathetic nervous system activity. Therefore, in chronic pain, treatment with systemic clonidine is of no significant value.

English Abstract↗
PubMed1997

Direct visualization of leukocyte/endothelial cell interaction during extracorporeal circulation (ECC) in a new animal model.

OBJECTIVE: The clinical complications of extracorporeal circulation (ECC) have been linked to a systemic activation of cellular and humoral components and to a dysregulation of the microcirculatory compartment. Since to date only in vitro methods exist for evaluation, we developed an animal model to study the effects of ECC on the microcirculation. To establish the model, we assessed whether these effects are dependent on the duration of ECC. METHODS: Intravital fluorescence microscopy was used on the dorsal skinfold chamber preparation in chronically instrumented, awake Syrian golden hamsters. ECC was realized using a micro-rollerpump and a silicon tube shunting blood between the carotid artery and the jugular vein. ECC was performed in three groups for various times (2, 10 and 20 min) after application of heparin at 300 IU/kg body wt. In hamsters, the application of high-dose heparin releases endothelial bound superoxide dismutase (SOD), a natural scavenger of oxygen-derived free radicals. Protocol II assigned two groups receiving heparin at different doses of 50 and 2000 IU/kg body wt. RESULTS: ECC for 2 min served as control to exclude effects from hemodilution and resulted in a minimal induction of leukocyte/endothelial cell interaction. Isovolemic ECC for 20 min resulted in an increase in rolling (from 11 +/- 3 to 38 +/- 20%, mean +/- S.D., P < 0.05) and adherent leukocytes (from 19 +/- 16 to 215 +/- 145 cells/mm2, mean +/- S.D., P < 0.05) in postcapillary venules. Microhemodynamic parameters and functional capillary density were not significantly affected. Arterial blood pressure and heart rate were stable. Heparin at 2000 IU/kg inhibited post-ECC leukocyte adhesion following ECC, whereas 50 IU/kg showed no protective effects. CONCLUSIONS: Leukocyte/endothelial cell interaction, induced by blood contact with synthetic surfaces, was directly visualized in vivo. The number of adherent leukocytes was dependent on the duration of ECC. The application of high-dose heparin followed by release of SOD almost prevented leukocyte activation, suggesting a formation of oxygen free radicals during ECC. The new application of the hamster model may allow to study the underlying pathomechanisms and to develop therapeutic/prophylactic strategies to avert problems associated with ECC.

Animals↗
PubMed1997

Doubly angled pleural drain circumventing the transcostal route relieves pain after cardiac surgery.

Standard pleural drainage after cardiac surgery is accomplished through the intercostal space and the divided parietal pleural, often causing severe additional chest pain. To circumvent this route of insertion a doubly angled polyvinyl chloride drain was developed which can be placed via the median approach through the rectus abdominis muscle just beside the anterior mediastinal drains without irritation of the heart and parietal pleura into the phrenico-costal sinus.

Adult↗
PubMed1994

Visualization of nutritive perfusion following tourniquet ischemia in arterial pattern skin flaps: effect of vasoactive medication.

We present an experimental model that makes it possible to investigate the effects of global ischemia and reperfusion on microvascular perfusion and viability of ill-proportioned (poorly designed) arterial pattern skin flaps in hairless mice. Skin flaps were created on the ears of hairless mice by dissecting two of three nutritional vessel bundles at the ear base. Under these nonischemic conditions, 19 percent of the total flap area went on to necrose (as a result of poor flap design). Global ischemia was induced to the flap tissue for 6 hours with a tourniquet clamp directly after flap incision. The extension of perfused tissue area and flap viability were assessed at the microcirculatory level by intravital video microscopy at 1, 3, 6, and 18 hours and 7 days after reperfusion in animals treated with either normal saline (control) or the vasoactive drug buflomedil hydrochloride (3 mg/kg of body weight per day, i.v., starting 4 hours prior to flap creation and continued at daily intervals until the end of the experiments). In untreated animals (n = 18), 1 hour after clamp release we observed reperfusion of 39.55 percent (38.5/44.9) of total flap area. Reperfusion remained unchanged within the following 5 hours. Within the next 12 hours, reperfused flap area was dramatically reduced to 21.9 percent (15.1/58.4). Seven days thereafter, only 18.8 percent (10.9/42.2) of total flap area remained viable. In contrast, we found in buflomedil-treated animals (n = 18) that 57.3 percent (53.5/62.9) of the total flap tissue was reperfused within the first hour after clamp release (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Impact of ischemia on tissue oxygenation and wound healing: improvement by vasoactive medication.

The influence of vasoactive medication on tissue oxygenation and wound healing was investigated in the ear model of the hairless mouse. Ischemia was induced to the ears by ligating 2 of the 3 main vessel bundels and verified by measurements of tcpO2. Reduced tissue oxygenation was followed by a prolongation of the time required for complete healing of standardized wounds. Treatment with the vasoactive drug Buflomedil (3 mg/kg/day iv.) resulted in enhanced recovery of the tissue from reduced oxygenation and likewise reversed the adverse effects of ischemia on wound healing. These results warrant the use of the drug in patients suffering from delayed wound healing due to peripheral arterial disease.

Animals↗