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W Hackl

Publications and source records attributed to W Hackl.

At least 55 records · Page 3Linked to original sources
PubMed1992

Direct binding of small nuclear ribonucleoprotein G to the Sm site of small nuclear RNA. Ultraviolet light cross-linking of protein G to the AAU stretch within the Sm site (AAUUUGUGG) of U1 small nuclear ribonucleoprotein reconstituted in vitro.

The major small nuclear ribonucleoproteins (snRNPs) U1, U2, U5 and U4/U6 participate in the splicing of pre-mRNA. U1, U2, U4 and U5 RNAs share a highly conserved sequence motif PuA(U)nGPu, termed the Sm site, which is normally flanked by two hairpin loops. The Sm site provides the major binding site for the group of common proteins, B', B, D1, D2, D3, E, F and G, which are shared by the spliceosomal snRNPs. We have investigated the ability of common snRNP proteins to recognize the Sm site of snRNA by using ultraviolet light-induced RNA-protein cross-linking within U1 snRNP particles. The U1 snRNP particles, reconstituted in vitro, contained U1 snRNA labelled with 32P. Cross-linking of protein to this U1 snRNA occurred only in the presence of the single-stranded stretch of snRNA that makes up the conserved Sm site. Characterization of the cross-linked protein by one and two-dimensional gel electrophoresis indicated that snRNP protein G had become cross-linked to the U1 snRNA. This was confirmed by specific immunoprecipitation of the cross-linked RNA-protein complex with an anti-G antiserum. The cross-link was located on the U1 snRNA by fingerprint analysis with RNases T1 and A; this demonstrated that the protein G has been cross-linked to the AAU stretch within the 5'-terminal half of the Sm site (AAUUUGUGG). These results suggest that the snRNP protein G may be involved in the direct recognition of the Sm site.

Autoantigens↗
PubMed1991

Muscle biopsy for diagnosis of malignant hyperthermia susceptibility in two patients with severe exercise-induced myolysis.

Muscle biopsy and in vitro contracture tests for diagnosis of susceptibility to malignant hyperthermia (MH) were performed in two patients who had developed fever and severe myolysis during exercise. MH susceptibility was confirmed in one patient, but in the other, exercise-induced heat stroke proved to be the correct diagnosis. Clinical presentation and epidemiology of exercise-induced MH and its relation to the heat stroke syndrome are discussed.

Adult↗
PubMed1990

Prediction of malignant hyperthermia susceptibility: statistical evaluation of clinical signs.

The anaesthetic records of 61 patients who had experienced adverse reactions thought to be malignant hyperthermia (MH) were reviewed retrospectively to evaluate the diagnostic importance of clinical symptoms. Using the in vitro contracture test, 38 (62%) patients were identified as MH susceptible (MHS), the remainder showing normal test results (MHN). Generalized rigidity, ventricular arrhythmias, cyanosis and postoperative myoglobinuria were observed significantly more often in MHS patients. Median values of body temperature and creatine kinase serum concentrations were significantly greater in the MHS group. Masseter spasm and sinus tachycardia were as common in MHS as in MHN individuals. Statistical models using generalized rigidity, ventricular arrhythmias, cyanosis and fever exceeding 38 degrees C for prediction of MH showed a maximum sensitivity and specificity of 78% and thus are not acceptable for clinical use. For definitive diagnosis of MH, the well established in vitro contracture test remains essential.

Adolescent↗
PubMed1990

Intravenous ofloxacin in severe infections.

The efficacy and tolerance of intravenous ofloxacin was studied in 70 patients suffering from soft tissue infections (n = 33), intra-abdominal abscesses (n = 14), septicaemia (n = 12), pneumonia (n = 9) and brucellosis (n = 2). The average daily dose was 6 mg/kg divided into two doses. Pathogens treated included Enterobacter cloacae (n = 14), Escherichia coli (n = 12), Staphylococcus aureus (n = 13), Pseudomonas aeruginosa (n = 11), Klebsiella pneumoniae (n = 10), Enterococcus faecalis (n = 8) and Streptococcus spp. (n = 5). Most patients had several underlying diseases. Most of the patients had received other antibiotic therapy without success. Clinically, 41% were considered cured, 19% improved and 30% failed to respond. Bacteriologically, pathogens were eradicated in 52.5% and persisted in 22.5%. Adverse reactions included an anaphylactoid reaction, abnormal liver function (n = 13) and insomnia (n = 2). This study suggests that higher doses of ofloxacin may be needed in deep seated infections.

Adolescent↗
PubMed1990

Anaesthesia in malignant hyperthermia-susceptible patients without dantrolene prophylaxis: a report of 30 cases.

The intra- and postoperative course of 30 anaesthetics in 24 MH-carriers verified by in vitro contracture tests is reported. None of the patients received dantrolene prophylactically and only agents known to be nontriggers were used for anaesthesia. Neither MH-related changes in perioperative heart rates, body temperatures, and CK levels nor any other symptoms of MH were observed. We conclude that the prophylactic use of dantrolene is not necessary in patients suspected to be prone to MH if triggering agents are avoided and the patients are closely monitored.

Adolescent↗
PubMed1990

Echocardiographic assessment of mitral valve function during mechanical cardiopulmonary resuscitation in pigs.

Using two-dimensional and M-mode echocardiography, mitral valve function was assessed during mechanical cardiopulmonary resuscitation (CPR). In 10 anesthetized pigs CPR began 1 min after induction of ventricular fibrillation; in all pigs three different compressive forces (200, 350, and 500 Newton [N]) were applied in randomized sequence for 3 min each, thus resulting in a reduction of anterior-posterior chest diameter by 15%, 20%, and 25%, respectively. Echocardiographic recordings of adequate technical quality were obtained from seven animals. During ventricular fibrillation, mitral valve leaflets showed fibrillatory movements without closure. During CPR systole with a compressive force of 200 N, the mitral valve closed in 114 of 700 CPR cycles (16%). This rate increased significantly (P less than 0.001) to 399 of 584 cycles (68%) with 350 N, and further to 470 of 494 cycles (95%) with 500 N. The higher mitral valve closure incidence was linked to statistically significant increases in systolic cerebral (+125%) and diastolic myocardial perfusion pressures (+136%) and cardiac output. We thus conclude that with low compressive force blood flow during mechanical CPR is due mainly to the chest pump mechanism, whereas the cardiac pump mechanism is effective with high compressive forces.

Animals↗
PubMed1990

Anesthesia in malignant hyperthermia susceptible patients.

The intra- and postoperative course of 30 general and 3 regional anesthetics in 27 MH-carriers verified by in vitro contracture tests is reported. None of the patients received dantrolene prophylactically. Disposable tubings were used for ventilation, vaporizers and soda lime were removed. ECG, esophageal temperature, blood pressure, oxygen saturation, and end tidal pCO2 were monitored. Minor tranquilizers were offered for premedication. Fentanyl, thiopentone, nitrous oxide, non depolarizing relaxants, neuromuscular antagonists and naloxone were used. In three patients, surgery was performed during epidural or spinal anesthesia with the use of amide local anesthetics. Neither MH-related changes in perioperative heart rates, body temperatures, and CK levels nor any other symptoms of MH were observed in any patient. The anesthetic techniques used seem to be safe and reliable; the anesthetic management of known MHS patients is discussed in detail.

Adult↗
PubMed1989

Effect of large volume replacement with balanced electrolyte solutions on extravascular lung water in surgical patients with sepsis syndrome.

We investigated the effect of large volume replacement with balanced electrolyte solutions on extravascular lung water (EVLW) in 16 adult surgical patients with sepsis syndrome. Patients entered the study within the 24 h period following surgical interventions for acute necrotizing pancreatitis, intra-abdominal abscesses, and/or peritonitis. Sequential measurements (n = 108) were made at intervals of 6-12 h over a 48 h period. There were no significant differences between initial and final values of thermal-dye EVLW (5.0 +/- 1.1 vs. 5.7 +/- 1.1 ml/kg), plasma colloid osmotic pressure (COP, 13.3 +/- 2.5 vs. 13.2 +/- 2.9 mmHg), pulmonary artery wedge pressure (PAWP, 9.2 +/- 3.0 vs. 10.8 +/- 3.0 mmHg), and COP-PAWP gradient (4.0 +/- 3.5 vs. 2.4 +/- 3.9 mmHg). All results expressed as (mean +/- SD). The EVLW did not correlate with plasma COP, PAWP, or COP-PAWP gradient. We conclude that large volume replacement with balanced electrolyte solutions with the secondary decrease in plasma COP and COP-PAWP gradient do not necessarily contribute to a substantial increase in EVLW. This study fails to show any causal relationship between decrease in plasma COP or COP-PAWP gradient and oedema formation in the lung.

Adult↗
PubMed1989

[Preoperative plasma exchange in treatment of plasma-related coagulation disorders before liver transplantation].

PATIENTS AND METHODS: Seventy-two consecutive patients undergoing orthotopic liver transplantation at the Department of Surgery I, University of Vienna Medical School (OLT nos. 1 to 72), were evaluated. Their mean age was 47 years (range: 18-63 years). The indications for liver transplantation are listed in Table 1. All transplant procedures were performed without using a bypass technique. The intraoperative management and surgical procedure have been described elsewhere [7]. Patients were categorized in two groups, each of which was divided in two subgroups. Group I consisted of 18 patients transplanted before the introduction of preoperative plasma exchange. These were retrospectively allocated to two subgroups on basis of their preoperative prothrombin times (PT): A (n = 9): preoperative PT less than 40%; B (n = 9): preoperative PT greater than 40%. The two subgroups of group 2, which contained 54 patients, were compared on a prospective basis: C (n = 32): preoperative PT above 40%; D (n = 22): PT on admission below 40%, preoperative plasma exchange. Comparison of the two subgroups was based on the following parameters: (1) pre-exchange PT (subgroup D); (2) preoperative PT (= PT post-plasma exchange in subgroup D; (3) intraoperative infusion volumes (balanced electrolyte solutions and human albumin to maintain an intravascular colloid osmotic pressure greater than 16 mm Hg); (4) transfusion volumes (whole blood stored for no more than 72 h or packed red cells and fresh plasma, as available; and (5) intraoperative sodium bicarbonate requirements to maintain an arterial pH greater than 7.20. RESULTS: (Table 2) . Prothrombin time (PT): Group 1: Patients in subgroup A had a mean preoperative PT of 34% (range: 15%-40%). This was significantly lower than in subgroup B (74%; 52%-100%; P less than 0.001). Group 2: The pre-exchange mean PT in subgroup D was 27% (12%-39%) vs. 68% in subgroup C (45%-104%), the difference being highly significant (P less than 0.0001). In patients in subgroup D a mean plasma volume of 3638 ml was exchanged by plasmapheresis. This resulted in a significant increase in PT to 55% (Table 3). As a result, the preoperative post-exchange PT in subgroup D was slightly but significantly (P less than 0.005) less than in subgroup C. Transfusion volumes: Group 1: Patients in subgroup A needed significantly more blood units than those in subgroup B (55.3 units [19-110] vs. 18.7 [3-33]).(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1989

[The action of ketamine on muscle contractile behavior. In vitro studies on the musculature of subjects susceptible to malignant hyperthermia].

Since ketamine has been incriminated as triggering malignant hyperthermia (MH) [3, 9, 13, 14, 18], but has still been used uneventfully in MH susceptible patients, we performed an in vitro study to examine the safety of ketamine for use in human MH. METHODS. Muscle specimens of 20 patients who had muscle biopsies to diagnose MH were investigated. In every patient diagnostic contracture tests (2 halothane (Hal) and 2 caffeine (Caf) were done according to the protocol established by the European MH group (EMHG). In addition, one test unit for investigating the effect of stepwise increased bath-concentrations of ketamine (5, 10, 20, 60, 120, 240 and 960 mumol/l) and a further one serving as control (no drugs added to the bath) were used. Combined Hal (2 vol%) and Ket (960 mumol/l) tests were performed in 9 patients (4 MHS, 4 MHN, 1 MHEh). Changes in baseline contractures and mechanical twitch tension were evaluated. RESULTS. The diagnostic test showed MHS in 8, MHN in 8 and MHEh in 4 patients. Ketamine did not induce baseline contractures in any of the tests performed. Contractures induced by 2 vol% of halothane in 4 MHS muscles did not change significantly when ketamine was added to the bath (concentration 960 mumol/l). A significant, dose-related decrease in mechanical twitch tension occurred, when ketamine was added to the test. At the highest concentration (960 mumol) twitch tension was reduced by 55%. Twitch tension remained stable in untreated muscles. No significant differences were found between the specimens from MHS, MHN and MHE patients. This reduction in twitch tension was more pronounced in specimens exposed to both halothane (2 vol%) and ketamine (960 mumol/l), resulting in an average decrease of 71%. CONCLUSION. In accordance with Fletcher et al., our results indicate that ketamine - at least in vitro - does not trigger MH. In MHS muscles, ketamine does not augment halothane-induced baseline contractures. The ketamine-induced reduction of mechanical twitch tension in directly stimulated human muscles has not been described before. Analogous findings in frog sartorius muscles can be found in the literature. Whereas the effect of ketamine on indirectly stimulated muscle has been investigated by several authors, the underlying mechanism of ketamine-induced twitch suppression in directly stimulated muscles is not known. Inhibition of calcium release from or accelerated uptake into the sarcoplasmatic reticulum have been reported.

Caffeine↗
PubMed1989

[Liver transplantation--anesthesiology aspects].

Based on our experience in 82 liver transplant procedures performed without using a bypass-technique, we report on our current perioperative anaesthetic management. Preoperative plasma exchange with fresh frozen plasma proved very effective in 16 patients with severe coagulation defects, leading to a significant increase in prothrombin time from 27 to 55%. Intra- and postoperative haemodynamic profiles of 48 patients are presented. Baseline measurements revealed a hyperdynamic circulatory state with elevated cardiac index (CI) and heart rate in all patients. During the anhepatic phase CI and mean arterial pressure (MAP) were persistently lowered. Immediately after reperfusion of the graft, reflux of the stagnant venous content induced a significant increase in CI and led to a moderate elevation of pulmonary artery pressure. MAP showed a rather slow recovery, but was within the normal range at the end of surgery. Oxygen consumption index, which was significantly lowered during the anhepatic period, excessively increased after reperfusion of the graft.

Adult↗
PubMed1988

Three-dimensional location of ribosomal protein BL2 from Bacillus stearothermophilus, a key component of the peptidyl transferase center.

Protein BL2 from Bacillus stearothermophilus has been localized by immunoelectron microscopy on the interface side of the 50 S subunit, beneath the angle formed between the central protuberance and the L1 protuberance. The immuno-electron microscopic data suggest that the interface region of the 50 S particle is not as flat as most of the proposed three-dimensional models suggest, but instead there is a significant concavity. Since several studies demonstrated that BL2 is implicated in peptidyl transferase activity or at least located close to the peptidyl transferase center, the location of protein BL2 also provides information as to the location of this important functional domain.

Acyltransferases↗