Biomedical subjects

J Holzinger

Publications and source records attributed to J Holzinger.

11 recordsLinked to original sources

PubMed2006

Cardiac re-synchronization therapy: effects on myocardial perfusion at rest, after vasodilation and oxygen consumption.

AIM: Cardiac resynchronization therapy (CRT) has been shown to improve haemodynamics and clinical symptoms in heart failure patients. The present study evaluated the effects of a 4-month CRT on myocardial blood flow (MBF) at rest, after vasodilation and on myocardial oxygen consumption (MVO(2)). PATIENTS, METHODS: We studied 16 patients with idiopathic dilated cardiomyopathy prior to and during CRT performed as biventricular pacing. Resting MBF and MVO(2) were determined from an (11)C-acetate PET study and vasodilator MBF from a (13)N-ammonia study. RESULTS: MBF at rest (0.55 +/- 0.10 ml/min/g), after vasodilation (1.20 +/- 0.45 ml/min/g), and MVO2 (0.082 +/- 0.014/min) did not change by mid-term CRT at a global level (0.57 +/- 0.11 ml/min/g; 1.32 +/- 0.49 ml/min/g; 0.085 +/- 0.018/min), whereas the rate pressure product (RPP) normalised MVO(2) decreased from 0.104 +/- 0.024 to 0.086 +/- 0.018/min (p = 0.02). At baseline, the regional analysis revealed significantly higher values for all parameters in the lateral wall than for those in the other walls. Under CRT the regional differences between the resting parameters equalized and all parameters showed significant lower coefficients of variation. CONCLUSION: Effects of mid-term CRT on resting MBF, vasodilator MBF and MVO(2) occur at a regional level. The resynchronization is associated with a more homogenous distribution pattern of these parameters among the myocardial walls. Substantial alterations to global MBF at rest, after vasodilation or to MVO(2) are not detectable. Regarding the RPP normalised MVO(2), there is evidence of improved ventricular efficiency through CRT.

Aged↗

PubMed2001

Successful use of cardiac allograft from serotonin antagonist intoxication.

BACKGROUND: Compromised organ donors are generally not accepted for heart transplantation (HT) despite the increasing number of critically ill patients on the waiting lists. By extending the donor criteria to include certain cases of intoxication, the organ shortage may be reduced. METHODS: The case of a successful orthotopic HT with an allograft from a donor poisoned by antidepressant overdose is presented. RESULTS: Early graft function was satisfactory with anteroseptal dyskinesis and an ejection fraction of 75% on echocardiography. The cardiac allograft recipient suffered some postoperative complications including gastrointestinal problems. The following period was up to now uneventful. Discharge from the intensive care unit was after 4 days. In-hospital stay was prolonged at 26 days. CONCLUSIONS: Because of limited myocardial toxicity, donor hearts from certain victims of antidepressant intoxication may be safely used for HT. Existing cardiac organ donor criteria must be reevaluated to maximise the available organ pool.

Adult↗

PubMed2001

ATP-induced structural change of the thermosome is temperature-dependent.

Protein folding by chaperonins is powered by ATP binding and hydrolysis. ATPase activity drives the folding machine through a series of conformational rearrangements, extensively described for the group I chaperonin GroEL from Escherichia coli but still poorly understood for the group II chaperonins. The latter--archaeal thermosome and eukaryotic TRiC/CCT--function independently of a GroES-like cochaperonin and are proposed to rely on protrusions of their own apical domains for opening and closure in an ATP-controlled fashion. Here we use small-angle neutron scattering to analyze structural changes of the recombinant alpha-only and the native alphabeta-thermosome from Thermoplasma acidophilum upon their ATPase cycling in solution. We show that specific high-salt conditions, but not the presence of MgATP alone, induce formation of higher order thermosome aggregates. The mechanism of the open-closed transition of the thermosome is strongly temperature-dependent. ATP binding to the chaperonin appears to be a two-step process: at lower temperatures an open state of the ATP-thermosome is predominant, whereas heating to physiological temperatures induces its switching to a closed state. Our data reveal an analogy between the ATPase cycles of the two groups of chaperonins and enable us to put forward a model of thermosome action.

Adenosine Triphosphatases↗

PubMed2000

Conformational rearrangements of an archaeal chaperonin upon ATPase cycling.

Chaperonins are double-ring protein assemblies with a central cavity that provides a sequestered environment for in vivo protein folding. Their reaction cycle is thought to consist of a nucleotide-regulated alternation between an open substrate-acceptor state and a closed folding-active state. The cavity of ATP-charged group I chaperonins, typified by Escherichia coli GroEL [1], is sealed off by a co-chaperonin, whereas group II chaperonins--the archaeal thermosome and eukaryotic TRiC/CCT [2]--possess a built-in lid [3-5]. The mechanism of the lid's rearrangements requires clarification, as even in the absence of nucleotides, thermosomes of Thermoplama acidophilum appear open in vitrified ice [6] and closed in crystals [4]. Here we analyze the conformation of the thermosome at each step of the ATPase cycle by small-angle neutron scattering. The apo-chaperonin is open in solution, and ATP binding induces its further expansion. Closure seems to occur during ATP hydrolysis and before phosphate release, and represents the rate-limiting step of the cycle. The same closure can be triggered by the crystallization buffer. Thus, the allosteric regulation of group II chaperonins appears different from that of their group I counterparts.

Adenosine Triphosphatases↗

PubMed2000

Laparoscopic cholecystectomy and interventional endoscopy for gallstone complications during pregnancy.

BACKGROUND: Symptomatic or complicated gallstone disease is the most common reason for nongynecological operations during pregnancy. Gallstones are present in 12% of all pregnancies, and more than one-third of patients fail medical treatment and therefore require surgical endoscopy or laparoscopy. Gallstone pancreatitis and jaundice during pregnancy is associated with a high recurrence rate, exposing both fetus and mother to an increased risk of morbidity and mortality. METHODS: During a 4-year period, all pregnant patients (n = 37) with symptomatic or complicated gallstone disease were studied prospectively at the Landeskrankenhaus in Salzburg, Austria. Five patients had an endoscopic retrograde cholangiopancreatogram (ERCP) for biliary pancreatitis or jaundice; two of these underwent subsequent laparoscopic cholecystectomy. Another seven patients required laparoscopic cholecystectomy for severe pain or cholecystitis; all were in their 13th-32nd gestational week. Access was established by Veress needle in all cases. Insufflation pressure was 8-10 mm Hg, and mean operative time was 62 min. RESULTS: All patients delivered full-term, healthy babies. There were no postendoscopic or postoperative complications. All patients enjoyed full relief from their symptoms; there were no recurrences of pancreatitis or jaundice. CONCLUSIONS: The combination of ERCP and laparoscopic cholecystectomy offers a safe and effective option for the definitive treatment of complicated gallstone disease and intractable pain during pregnancy, and there is sufficient access for the combined treatment to be employed.

Cholangiopancreatography, Endoscopic Retrograde↗

PubMed1999

Improvement in coronary flow reserve determined by positron emission tomography after 6 months of cholesterol-lowering therapy in patients with early stages of coronary atherosclerosis.

BACKGROUND: Early stages of coronary atherosclerosis are characterized by a mainly functional impairment of coronary vasodilator capacity under the impact of such risk factors as hypercholesterolemia. The goal of this study was to determine whether 6-month cholesterol-lowering therapy improves coronary flow reserve in patients with angina, reduced flow reserve despite minimally diseased coronary vessels or even normal angiogram, and mild to moderately elevated LDL levels on average. METHODS AND RESULTS: We noninvasively investigated 23 consecutive patients (18 men, 5 women; mean age, 56+/-7.6 years) with a mean LDL level of 165+/-34 mg/dL at baseline by PET for myocardial blood flow measurement with [13N]ammonia at rest and under dipyridamole stress (0.56 mg/kg) before and after lipid-lowering therapy with simvastatin for 6 months. Between baseline and the 6-month follow-up, total cholesterol concentration fell from 241+/-44 to 168+/-34 mg/dL, and the LDL level decreased from 165+/-34 to 95+/-26 mg/dL (P<0.001). Overall, coronary flow reserve increased from 2.2+/-0.6 to 2.64+/-0.6 (P<0.01). Maximal coronary flow increased significantly from 182+/-36 to 238+/-58 mL/minx100 g (P<0.001) at follow-up. Minimum coronary resistance declined significantly from 0. 51+/-0.12 to 0.40+/-0.14 mm Hg. mL-1. minx100 g (P<0.001). Concomitantly, a regression of anginal symptoms was observed in most patients. CONCLUSIONS: Our results suggest that cholesterol-lowering therapy with simvastatin may improve overall coronary vasodilator capacity assessed noninvasively by PET in patients with mild to moderate hypercholesterolemia. Consequently, intensive lipid-lowering therapy is considered a vasoprotective treatment for selected patients in very early stages of coronary atherosclerosis with the potential of preventing further disease progression.

Adult↗

PubMed1998

[Improved coronary vasodilator capacity by drug lipid lowering therapy in patients in the early stage of coronary atherosclerosis with reduced coronary reserves and moderate LDL hypercholesteremia].

BACKGROUND: An abnormal coronary flow reserve represents an early marker of impaired blood flow regulation in the natural history of coronary atherosclerosis under the impact of risk factors such as hypercholesterolemia. Our clinical investigation was aimed at assessing noninvasively the integrative coronary flow response to dipyridamole stress in 18 consecutive patients with microvascular angina, only moderately elevated LDL-cholesterol levels (168 +/- 33 mg/dl), and reduced vasodilator capacity despite normal (n = 9) or slightly abnormal (n = 9) coronary arteriograms (minimal disease with luminal irregularities and/or diameter reduction < or = 30%) before and after 6-month lipid-lowering therapy (simvastatin). METHODS: Regional and averaged myocardial blood flow were measured at rest and after dipyridamole induced vasodilation (0.56 mg/kg) using dynamic positron emission tomography (PET) and N-13 ammonia as flow tracer related to a 3-compartment kinetic model. Baseline data (mean +/- SD): 13 males, 5 females; mean age: 56 +/- 8 years; basal coronary flow: 90 +/- 22 ml/min x 100 g; after lipid intervention: 93 +/- 18 ml/min x 100 g (n.s.). Total cholesterol: 246 +/- 45 mg/dl. RESULTS AFTER 6-MONTH LIPID INTERVENTION: Total cholesterol decreased to 170 +/- 36 mg/dl (p < 0.001); mean LDL level: 97 +/- 26 mg/dl (p < 0.001). Coronary dilator capacity increased, assessed in terms of minimal coronary resistance: 0.38 +/- 0.08 vs 0.49 +/- 0.09 units at baseline (p < 0.01), myocardial blood flow under dipyridamole: 232 +/- 43 vs 186 +/- 37 ml/min x 100 g at baseline (p < 0.01), and instantaneous flow ratio: 2.6 +/- 0.7 vs 2.2 +/- 0.6 (p = 0.06). Concomitantly, a considerable regression of angina was noticed in the majority of patients. CONCLUSIONS: An improvement of the non-invasively determined integrative dipyridamole induced coronary vasodilator capacity may be achieved after 6 months by intensive lipid lowering at a very early stage of coronary atherosclerosis. Consequently, aggressive cholesterol-lowering therapy represents an antiischemic and antianginal approach suggesting, at least in part, functional reversal and probably prevention of further disease progression.

Adult↗

PubMed1997

[Preoperative therapeutic splitting].

INTRODUCTION: The best clinical strategy for using ERC combined with LC is still unknown. Based on a wide discussion of literature reports the aim of our study is to critically analyse laparoscopic bile duct exploration and to correlate these data to our prospective study of "therapeutical splitting". PATIENTS AND METHODS: In a prospective study 1645 consecutive patients with sympomatic gall stone disease were examined by ultrasound. 309 patients had open cholecystectomy because of previous gastric surgery or perforation. Patients with a high probability of harbouring stones in the common duct or having other related disorders like biliary pancreatitis had ERC, EPT and stone extraction. 1336 patients had attempted LC. RESULTS: At endoscopy 70% of the 260 patients required therapy like EPT and/or stone extraction, 95% consequently had their gallbladder removed laparoscopically. Including the patients with biliary pancreatitis morbidity amounted to 3% with no mortality. In the non-endoscopic group with 1076 patients conversion was 6.8%, morbidity was 4.3% and mortality 0.09%. Residual stones were found in 0.5% so far. CONCLUSION: If selection criteria for bile duct pathology have a high sensitivity and specificity and endoscopical stone clearance rate is high, at present "therapeutical splitting" still is the method of choice.

Adolescent↗

PubMed1997

[Treatment of postoperative bile fistulas after laparoscopic cholecystectomy by ERCP, EPT and bile duct drainage].

BACKGROUND: Bile leakage as a complication following cholecystectomy can be found more frequently after laparoscopic cholecystectomy (LC) than after open cholecystectomy. The present study planned to find out the importance of ERCP, sphincterotomy and temporary drainage of the bile duct system in the treatment of bile leakage. PATIENTS AND METHODS: From July 1992 to October 1996 15 consecutive patients presenting with bile leakage following LC underwent endoscopic therapy by CBD-drainage with sphincterotomy (n = 11), CBD-drainage without sphincterotomy (n = 1) and sphincterotomy alone (n = 3). RESULTS: Closure of the bile leakage could be achieved in all cases, biliary secretion stopped after 2.1 days (1-7 days). One dislocation of the drainage into the CBD was found and could be treated endoscopically. Endoscopy-related mortality was 0%. CONCLUSIONS: Endoscopic therapy offers a safe, effective and minimal invasive method in the treatment of bile leakage following LC.

Adult↗

PubMed1997

[Urgent ERCP and early elective laparoscopic cholecystectomy in biliary pancreatitis].

BACKGROUND: For many years the best algorithm of treatment for complicated gallstone disease has been intensively discussed. Gallstone pancreatitis with cholangitis still belongs to the most often identified causes of death of necrotizing pancreatitis. The reduction of complication and lethality rates was mainly achieved by urgent ERCP and sequential cholecystectomy. In a prospective study we have combined endoscopic therapy with laparoscopic cholecystectomy (LC) and are discussing the results. PATIENTS AND METHODS: Between May 1991 and December 1996 146 patients with biliary pancreatitis were subjected to ERCP after laboratory tests and ultrasound screening of the biliary system. If there were no contraindications and the gallbladder was still in situ, LC was attempted during the initial admission. RESULTS: Of the 70 patients with attempted LC 26 had common bile duct calculi, 23 had an impacted papillary stone and 10 had signs of a stone passage. 59 patients underwent LC successfully, a conversion to open surgery was necessary in 11 patients. The morbidity rate amounted to 7%, lethality to 0%. DISCUSSION: Since a more liberal indication for ERCP in the management of acute pancreatitis was introduced the number of biliary related cases of acute pancreatitis is increasing. In response to early endoscopic bile duct clearance the rates of morbidity and mortality can be significantly reduced. Early LC is the ideal complementary treatment option to absolutely prevent recurrencies.

Adult↗

PubMed1997

[Potential for improvement of combined endoscopic-surgical treatment of bleeding gastroduodenal ulcer].

A total of 119 patients (January 1995-December 1996; 53 women, 66 men) with a medium age of 63.1 years were admitted to hospital with bleeding gastroduodenal ulcer. Emergency gastroduodenoscopy was performed immediately in all cases, sclerotherapy in 94 cases (78.9%). Control endoscopy was done routinely after 12-24 h; the recurrent bleeding rate amounted to 14.3%, mortality was 5%, and surgical intervention was necessary in 8.4% with a mortality of 40% (!).

Adolescent↗