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Biomedical subjects

J Kemnitz

Publications and source records attributed to J Kemnitz.

At least 19 recordsLinked to original sources
PubMed2001

Caloric restriction mimetics: physical activity and body composition changes.

As the only paradigm that has consistently increased life span and inhibited the onset and/or progression of disease, dietary restriction has multiple effects on a variety of organ systems. In this brief review, the goal of the panel was to attempt to understand the role of changes in physical activity and body composition as possible modulators of the life span in experimental animals and humans. We focus on whether changes in exercise behavior and body composition produce similar changes as those found in dietary restriction and whether these changes can be used to either replace or enhance the beneficial effects of dietary restriction. The complexity of the two stimuli is emphasized in our report, with suggestions offered on how to better interpret existing research. Our panel briefly examines evidence in experimental animals and humans about the specific contributions of each of these factors to altering life span and age-related pathologies. We also discuss additional animal studies and/or human intervention studies that could be performed to clarify these issues. Finally, we provide suggested avenues for future research in this area of changes in physical activity and body composition as dietary restriction mimetics.

Animals↗
PubMed2000

[Effectiveness and tolerance of depot leuprorelin acetate for preoperative endometrium flattening before endometrial ablation. German Leuprorelin Study Group].

OBJECTIVE: In order to assess the efficacy and tolerability of leuprorelin acetate depot in pre-operative flattening of the endometrium prior to hysteroscopic endometrial ablation, 94 patients from eight centres were included in the per protocol analysis. MATERIAL AND PATIENTS: The patients included were pre- or peri-menopausal, had completed their family planning and had intractable uterine bleeding. The primary target criterion was the reduction in maximum endometrial thickness after two injections of leuprorelin acetate depot with an interval of four weeks between injections. Surgery took place two weeks after the second injection. RESULTS: Sufficient pre-treatment was achieved in 91.5% of the patients with > 50% decrease and/or a type 1 endometrium according to sonographic and/or endometrial atrophy (Score 11) according to the central histological evaluation. The endometrium was flattened by a mean of 4.0 +/- 4.1 mm. In terms of clinical response, amenorrhoea, hypomenorrhoea or normal menstruation were achieved after endometrial ablation. Hence 91.5% of patients benefited from the overall treatment after six weeks and still 83% after six months. The trial medication was well tolerated overall. The most common side-effect described was hot flushes which could be attributed to the deliberate oestrogen withdrawal. CONCLUSION: In view of the good study results, hormone-suppressive pretreatment of the endometrium can be recommended prior to elective ablation. Surgery should take place during the oestrogen-suppressed phase.

Adult↗
PubMed1997

Successful regrafting of a transplanted liver.

We report on the successful regrafting of a transplanted liver. The donor liver was first grafted into a patient suffering from cryptogenic cirrhosis; the patient died 1 day after the elective transplantation of cerebral bleeding. The well-functioning graft was harvested again and transferred to our institution. After another 12 h of cold ischemia, the liver was reperfused in an urgently registered patient with recurrence of hepatitis B in his first graft. The transplantation was successfully performed and the patient is now doing well, more than 5 months after regrafting with the reused liver.

Humans↗
PubMed1997

[Animal experiment studies of arterialization of the portal vein in liver transplantation using the Göttingen minipig].

The aim of the present experimental investigation was to assess the circulatory, biochemical and histopathological consequences of complete portal vein arterialization of the transplanted liver in 'Göttinger' miniature pigs. Orthotopic liver transplantations using a passive portojugular shunt were performed in six male 'Göttinger' miniature pigs. Using an iliac artery segment interposition of the animal donor, the hepatic artery (HA) of the transplant liver was anastomized end-to-end and the portal vein (PA) also united with the internal iliac artery stump end-to-end. The central anastomosis was performed onto the suprarenal aorta. Portal vein blood was drained into the infrahepatic caval vein via an end-to-side shunt (PCS). During the course, the following parameters were determined: arterial blood pressure, venous pressure, cardiac output, electromagnetic blood flow measurements across the HA, PA, and PCS, PA mean pressure, transaminases, partial thromboplastin time and fibrinogen. Liver biopsies and autopsy specimens were investigated. One of six animals died a few hours postoperatively, two of six died after 48 and 72 h, respectively, whereas three pigs survived the scheduled 7 days. The cardiac output fell intraoperatively initially by an average of 20% but had approximately the starting volume of 2.2 l/min at the end of the operation. Although the diameter of the anastomosis was reduced to 4 mm, the flow in the arterialized PA on average was 340 ml/min when the vessel clamp was opened. At the end of operation the mean was 380 ml/min, the interval of measurement being 75 min. The flow across the PCS and the HA were constant during the course. As mechanism for this phenomenon, autoregulation of the liver blood flow on a sinusidal level has been suggested. The biochemical results and the histopathological findings showed no change compared to previous findings in a control group of animals in which liver transplantation was performed by our team. Complete arterialization of the PA is well tolerated in liver transplantation in 'Göttinger' miniature pigs with regard to circulation and liver function in a short-term trial of a maximum of 7 days. Long-term results are still to come.

Anastomosis, Surgical↗
PubMed1996

Auxiliary liver transplantation: regeneration of the native liver and outcome in 30 patients with fulminant hepatic failure--a multicenter European study.

Auxiliary liver transplantation (LT) is a special procedure of LT which could be proposed to patients with fulminant hepatic failure (FHF) and has for aim that complete regeneration of the native liver (NL) left in place will allow the graft recipient to resume normal liver function after allograft withdrawal. We report 30 cases of auxiliary LT performed for FHF in 12 European centers. Twenty-five of 30 patients were younger than 50 years. The cause of FHF was hepatitis A virus (HAV) in 4 patients, hepatitis B virus (HBV) in 7, paracetamol overdose in 5, ecstasy in 2, hepatotoxic drugs in 4, autoimmune hepatitis in 2, liver lesions of preeclampsia in 1 and unknown in 5. A postoperative, both clinical and histological follow-up of more than 3 weeks was obtained in 22 patients, enabling us to look for indicators predictive of NL regeneration and outcome. Histological changes observed in the NL included complete regeneration in 68%, incomplete regeneration with obvious fibrous sequelae in 14% and severe liver fibrosis or cirrhosis in 18%, of the 22 patients studied. The percentage and distribution of necrosis observed in tissue samples of the NL at the time of transplantation was not related to the final outcome. Complete NL regeneration was observed in 15 patients, out of whom 14 were younger than 40 years. Patients with complete regeneration were mainly affected by FHF due to HAV, HBV, or paracetamol overdose. After a follow-up of 18/11 (mean/median) months (range, 3 to 67 months), 19 of the 30 patients (63%) survived and 13 of them (68%), i.e., 43% of the 30 patients, had resumed normal NL function, with interrupted immunosuppression, the ultimate goal of emergency auxiliary LT. We conclude that, in patients with FHF, auxiliary LT is a procedure feasible in a number of centers and is associated with a complete regeneration capability of the NL in a majority of survivors, especially in those younger than 40 years. Confirmation of these encouraging preliminary results by large-scale prospective studies is required.

Adolescent↗
PubMed1996

[Lymphangiomatosis as the cause of therapy refractory chylothorax and ascites].

After five weeks of progressing dyspnoea and pain in the lower abdomen a 44-year old woman was admitted in our hospital unit. A massive chylothorax was identified as the cause of the dyspnoea. Clinical and pathological findings were consistent with the diagnosis of lymphangiomyomatosis. The ligature of the thoracic duct as well as pleurodesis and the application of medroxyprogesterone were without any significant effect. Severe complications made further treatment in the intensive-care unit imperative. Symptomatic treatment led only to a short remission. Five months after the outbreak of the disease the patient died from multiple organ failure.

Adult↗
PubMed1996

Longterm efficiency of high dose inotropic support in an infant after repair of Fallot's tetralogy.

A 23 month old boy with highly symptomatic tetralogy of Fallot (TOF) underwent repair. Inspite of cold Bretschneider cardioplegic solution twice the heart was beating soon after application of the cardioplegic solution each time. Soon after transfer to the intensive care unit the patient developed low cardiac output (LCO). The following days high doses of inotropic support ware necessary to maintain sufficient arterial pressure. The dosages of dobutamine (up to 49 micrograms/kg/min); norepinephrine (up to 5.28 micrograms/kg/min, and epinephrine (up to 16 micrograms/kg/min), respectively, were twice and three times as high as common maximum recommendations. After having recovered from acute renal failure requiring hemodialysis from the 5th to the 37th postoperative day the child was discharged 9 weeks after the intervention. The very unusual and interesting course of this boy is described and the form and grade of the inotropic support is discussed.

Acute Kidney Injury↗
PubMed1993

[Cardiac pacemakers and implantable cardioverter-defibrillators in the perioperative phase].

Recent developments have changed the techniques and indications for different methods of temporary cardiac pacing. Temporary transvenous pacing involves endocardial right ventricular stimulation by a bipolar electrode, introduced directly via a vein, or through a "paceport" pulmonary artery catheter. A "multipurpose" pulmonary artery catheter permits both atrial and ventricular sensing and pacing. Noninvasive transcutaneous cardiac pacing is safe, fast, and easily applicable. However, pain and discomfort from cutaneous nerve or muscle stimulation may be intolerable for unsedated patients. Transoesophageal cardiac pacing is usually successful only for atrial stimulation, e.g., in sinus node bradycardia, but is not indicated in patients with impaired AV-conduction. In patients with implanted pacemakers, temporary cardiac pacing can both impair or improve the haemodynamic situation. Implanted pacemakers should always be checked following surgery involving electrocautery. Preoperatively, rate-responsive pacemakers should be re-programmed so as to avoid activation of the rate-responsive function. Automatic implantable cardioverter-defibrillators should be deactivated to avoid delivery of inappropriate shocks. In patients with implanted epicardial patch electrodes, transthoracic defibrillation can be difficult with routine defibrillation protocols and may require positioning of the paddles on the lateral chest wall. However, emergency noninvasive transcutaneous cardiac pacing is possible in such patients with normal thresholds.

Arrhythmias, Cardiac↗
PubMed1993

Chronic (or healed) myocarditis mimicking arrhythmogenic right ventricular dysplasia.

The aetiology of arrhythmogenic right ventricular dysplasia is still unknown, and there are few reports on familial coincidence in the literature. A case of a previously healthy man with an episode of acute myocarditis is described. After recovery from acute myocarditis, the patient was resuscitated from aborted sudden cardiac death 16 months later. Angiographic and electrophysiological evaluation suggested the pattern of arrhythmogenic right ventricular dysplasia. The case seems to suggest that arrhythmogenic right and/or left ventricular dysplasia could be mimicked by chronic (or healed) myocarditis.

Biopsy↗
PubMed1993

Bronchial circulation after experimental lung transplantation. The effect of long-term administration of prednisolone.

The effect of corticosteroids on bronchial healing after modified left lung transplantation was investigated in pigs. In groups I (n = 6) and II (n = 6), animals received cyclosporine (15 mg/kg per day) and azathioprine (2 mg/kg per day). In group II, prednisolone (1 mg/kg per day) was also administered. Bronchial blood flow was estimated at the donor carina and donor second carina with laser Doppler velocimetry and radioisotopes 7 days postoperatively; macroscopic and microscopic assessments of graft airways were performed. Bronchial blood was calculated relative to the recipient carina. In group II, bronchial blood flow at the donor carina and donor second carina was significantly higher than that of group I. Macroscopic assessment revealed more pronounced ischemic changes in group I (5 of 6 animals) than in group II (2 of 6 animals, p = not significant). Microscopically, airway samples from the donor carina revealed marked destructive changes in five of six animals in group I. In group II, only mild ischemic changes, which were limited to the respiratory epithelium, were seen. We concluded that the administration of prednisolone results in improved bronchial blood flow and decreased bronchial ischemia after lung transplantation.

Animals↗
PubMed1992

University of Wisconsin versus modified Euro-Collins solution for lung preservation.

In a canine model, the quality of lung preservation was assessed using pulmonary artery flush after prostacyclin administration with either modified Euro-Collins solution or University of Wisconsin solution. Twelve combined heterotopic heart and orthotopic left lung allotransplantations were performed after 6 hours of cold ischemia. Myocardial preservation was achieved using St. Thomas Hospital solution. Donor organs were anastomosed parallel to the recipient's heart and right lung, and the superior vena cava inflow was directed into the transplanted heart-left lung block after ligation of the recipient's superior vena cava proximal to the caval anastomosis. Postoperatively, cardiorespiratory function was evaluated separately for donor and recipient organs at an inspired oxygen fraction of 0.4 for a maximum of 12 hours. Significantly improved oxygenation and lower pulmonary vascular resistance index of the donor lung was observed in the University of Wisconsin + prostacyclin group, whereas pulmonary artery pressures showed no significant differences in between both groups. It is concluded that superior results in lung preservation can be achieved with pulmonary artery flush perfusion using University of Wisconsin solution and prostacyclin when compared with Euro-Collins solution and prostacyclin.

Adenosine↗
PubMed1992

Systemic recombinant tissue plasminogen activator lysis for left atrial thrombus formation after single-lung retransplantation.

This report describes a recipient of single-lung transplantation surviving extraordinary complications: (1) early graft failure mandating retransplantation; (2) left atrial thrombus formation, which resolved by recombinant tissue plasminogen activator lysis; (3) and development of a "locked-in-syndrome." Possible underlying mechanisms are discussed.

Extracorporeal Membrane Oxygenation↗
PubMed1992

Transcutaneous cardiac pacing in patients with automatic implantable cardioverter defibrillators and epicardial patch electrodes.

In patients with automatic implantable cardioverter defibrillators, insulation of the epicardial patch electrodes (patches) prevents externally applied current from passing through the electrode to the cardiac muscle so that external transthoracic and even internal defibrillation can be unsuccessful. Because emergency cardiac pacing may be required in such a case, a study was performed to evaluate whether, and at what threshold and electrode orientation, transcutaneous pacing is possible in patients with implanted patches. Thresholds for transcutaneous pacing were determined during general anesthesia in nine patients with patches sewn across the heart (anterior right and posterior left ventricles) either before or after surgery, or at both times (automatic implantable cardioverter defibrillator implantation/exchange with or without coronary artery bypass grafting). Because surgery per se can increase the pacing threshold, nine patients of similar body size and weight undergoing routine coronary artery bypass grafting also were evaluated and served as a control group. Pacing thresholds (stimulus duration: 50 ms) were determined during normothermia with a transportable transcutaneous pacer, and adult cutaneous electrodes were placed across the patients' chest in the standard anteroposterior and right-to-left orientations. In all patients with patch electrodes, antero-posterior pacing was possible at a mean threshold of 73 +/- 30 mA standard deviation (range: 40-140 mA). This threshold was not significantly different (Mann-Whitney test) from that in control patients before (57 +/- 20 mA; range: 30-90 mA) or after (94 +/- 24 mA; range: 40-120 mA) coronary artery-bypass grafting. The surgical procedure per se significantly increased the threshold (Wilcoxon test, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Pacing, Artificial↗
PubMed1992

[Electrocardiographic diagnosis of acute graft rejection after heart transplantation].

In order to evaluate the diagnostic value of standard-ECG (ST-ECG) and precordial mapping-ECG with 63 unipolar leads (PM-ECG) for detection of acute cardiac allograft rejection, 15 patients (12 male, 3 female; age range 24-64 years) were studied. ST-ECG and PM-ECG were recorded along with 94 endomyocardial biopsies. Twenty-four acute rejections were detected histologically. Using the ST-ECG, a reduction of the QRS-amplitude-sum (lead I, II, III, V1 and V6) greater than or equal to 5% in comparison with the ECG obtained 1 week before was found to be the best diagnostic criterion (sensitivity 63%, specificity 74%, positive predictive value 48%, negative predictive value 85%). By analysing the PM-ECG a drop of the QRS-amplitude greater than or equal to 12% in greater than or equal to 14/63 precordial leads was determined to be the most reliable parameter (sensitivity 79%, specificity 71%, positive predictive value 49%, negative predictive value 91%). In contrast to the high sensitivity of PM-ECG, ST-ECG was less suitable for detection of acute rejection. However, taking into account the high negative predictive value of PM-ECG, acute rejection could be excluded with high probability, if the QRS-amplitudes of the PM-ECG remained stable. This may lead to a lower frequency of routinely performed endomyocardial biopsies.

Adult↗