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Biomedical subjects

W Hackl

Publications and source records attributed to W Hackl.

At least 37 records · Page 2Linked to original sources
PubMed1999

Influence of exogenous application of n-3 fatty acids on meat quality, lipid composition, and oxidative stability in pigs.

The effect of dietary n-3 fatty acids on the fatty acid composition and lipid peroxidation of different tissues in pigs were studied. 20 castrated male pigs were included in this investigation, one half was fed daily a diet containing 1.3 g n-3 fatty acids/kg diet (control) and 10 pigs were fed a diet containing 14 g n-3 fatty acids/kg diet (n-3 diet) at the growing-finishing period. The intake of dietary n-3 fatty acids increased the concentration of these fatty acids in backfat, and the neutral and polar fractions of skeletal muscle and heart homogenates. The polar fraction showed an increased relative concentration of n-3 fatty acids in comparison to control, while the n-6 fatty acid content was reduced. In heart homogenates there was an enlargement of n-3 fatty acids both in polar lipids and in neutral lipids whilst n-6 fatty acids were decreased. Feeding n-3 fatty acid enriched diet had no influence on meat quality parameters drip loss, meat colour or pH value. The lipid peroxidation (measured as malondialdehyde equivalents) was in the order liver > heart > skeletal muscle with higher values in the n-3 group. However, by stimulation of oxidation by Fe2+/ascorbate for 3 hours the order of oxidative products in the n-3 group was muscle > liver > heart, whereas in the control group the order was liver > heart = muscle. Summarized, feeding a highly n-3 fatty acid enriched diet caused an incorporation of these fatty acids and increased the susceptibility to peroxidation in all investigated tissues.

Adipose Tissue↗
PubMed1999

Differential profile of facial injuries among mountainbikers compared with bicyclists.

BACKGROUND: Bicyclists and mountainbikers are prone to facial trauma. In the current study, we present a large series of cycling-related sports trauma to the face in an effort to identify the injury pattern among mountainbikers compared with bicyclists. METHODS: The medical records of a single pediatric and adult Level I trauma center were evaluated from January 1, 1991, through October 31, 1996. All admissions with injuries caused by cycling-related sports were reviewed, analyzed, and compared according to age and sex distributions, causes of accidents, injury types, frequency, and localization of fractures and associated injuries. The injury types were divided into three categories: fractures, dentoalveolar trauma, and soft-tissue injuries. RESULTS: Five hundred sixty-two injured bicyclists (10.3% of all trauma patients) were registered at the Department of Oral and Maxillofacial Surgery, University of Innsbruck, Austria, during the study period, accounting for 31% of all sports-related or 48.4% of all traffic collisions, respectively. The review of the patient records revealed especially more severe injury profiles in 60 mountainbikers, with 55% facial bone fractures, 22% dentoalveolar trauma, and 23% soft-tissue injuries, compared with 502 street cyclists showing 50.8% dentoalveolar trauma, 34.5% facial bone fractures, and 14% soft-tissue lesions. The dominant fracture site in bicyclists was the zygoma (30.8%), whereas mountainbikers sustained an impressive 15.2% Le Fort I, II, and III fractures. Condyle fractures were more common in bicyclists, with 18.8% opposing 10.8% in mountainbikers. CONCLUSION: Appropriate design of helmets with faceguards will reduce the incidence of facial injuries caused by cycling-related accidents and incentives are needed for making helmet use compulsory for all cyclists, particularly for mountainbikers.

Adolescent↗
PubMed1999

Facial injuries in skiing. A retrospective study of 549 cases.

In the last 2 decades, reports of skiing injuries have shown an increasing number of skiers with severe trauma. This article provides an account of a retrospective study of 549 patients with 1155 facial injuries sustained while skiing who received treatment at the Department of Oral and Maxillofacial Surgery at the University Hospital in Innsbruck, Austria between 1991 and 1996. The study was based on a questionnaire answered by the patients and on case report forms. Most of the patients were male (65.2%) and were aged between 3 and 81 years (average 28.4 years). A simple fall while skiing was the main type of accident (45.9%), followed by collisions with other people (23.5%). Injuries were classified into 1 of 3 groups: (i) lesions of the soft tissue (32.2% of all injuries); (ii) dentoalveolar traumas (24.3%); and (iii) fractures of facial bones (43.5%). Lacerations and haematomas were the most frequent lesions in patients with injuries to the soft tissues. The group of patients with dentoalveolar trauma mainly presented with fractures of tooth crowns. Fractures involving the mandible and the zygomatic bone were predominant in patients in the third group. Concomitant injuries mainly included injuries to the brain and skull fractures. Treatment was ambulatory, or by admission and surgery. We did not observe an increase in the number of skiing accidents causing facial injury in the last 5 years. Facial injuries represented 4% of all skiing injuries, a lower proportion than in other sports.

Accidental Falls↗
PubMed1998

Effects of half the tidal volume during cardiopulmonary resuscitation on acid-base balance and haemodynamics in pigs.

The effects of half the tidal volume during cardiopulmonary resuscitation (CPR) on haemodynamics, acid-base balance, and oxygenation were studied in anaesthetized pigs. The animals were ventilated with a mean tidal volume of 12.5 +/- 0.5 ml/kg at a rate of 14/minute resulting in a mean arterial pCO2 of 40 +/- 3 mmHg. They were randomly assigned to two groups: in one group ventilation was performed with half the pre-arrest tidal volume (50% group; n = 9), in the other group ventilation remained unchanged during CPR (100% group; n = 10). After 8 minutes of CPR attempts were made to restore spontaneous circulation with epinephrine and countershocks. There were no differences in advanced life support requirements, haemodynamic parameters, and resuscitability between the two groups. During CPR up to 5 minutes after restoration of spontaneous circulation (ROSC) dead space ventilation was significantly higher in the 50% group compared with the 100% group (p < 0.05). During CPR (at 3 and 7 minutes) arterial pO2 values were significantly lower (218 +/- 136 and 221 +/- 120 mmHg vs. 381 +/- 130 and 352 +/- 147 mmHg; FiO2 1.0) and hyperventilation was less pronounced (34.4 +/- 7.3 and 31.3 +/- 7.7 mmHg vs. 26.2 +/- 5.6 and 26.9 +/- 6.3 mmHg) in the 50% group. Our results suggest that half the tidal volume during CPR is likely to establish a more physiological acid-base balance and has no adverse effects on haemodynamics in intubated pigs ventilated with pure oxygen.

Acid-Base Equilibrium↗
PubMed1997

Effects of porcine somatotropin on the chemical body composition and fat quality in growing-finishing pigs.

Seventy eight growing-finishing pigs (male castrates and females) of the cross-breed Pietrain x (Large White x German Landrace) were used to investigate the effects of pST treatment on the chemical composition of the body, the growth of adipocytes, and the fatty acid profile of the backfat. Intramuscular injections (1 or 3 mg pST) were administered daily from an average weight of 65 kg up to slaughter. After pST treatment significant changes in all studied characteristics were observed in barrows, whereas the females exhibited very small responses. The pST caused an increase of water and protein contents and a simultaneous decrease of lipid content especially in body parts rich in fat. Furthermore, the proportion of unsaturated fatty acids increased and the fat cell diameter decreased in the backfat.

Adipocytes↗
PubMed1996

Molecular cloning and subcellular localisation of the snRNP-associated protein 69KD, a structural homologue of the proto-oncoproteins TLS and EWS with RNA and DNA-binding properties.

We recently isolated and characterised a 69 kDa protein (69KD) found associated with spliceosomal small nuclear ribonucleoproteins (snRNPs). Here, we report the molecular cloning of a cDNA encoding this protein, its nucleic acid binding properties and its subcellular localisation. Sequence analysis of the 69KD cDNA revealed: (1) that 69KD shares structural similarity with the human RNA binding proteins TLS and EWS (95% and 65% identity, respectively), the products of two genes frequently targeted by tumour-specific chromosomal translocations; (2) that 69KD contains a consensus RNA binding domain (CS-RBD) and three Arg/Gly-rich RNA binding motifs, structural features typical of many RNA binding proteins, in particular of hnRNP proteins; and (3) that 69KD contains a single putative Cys2/Cys2 zinc finger domain, a characteristic of many DNA-binding proteins. Consistent with its possession of these motifs, 69KD display a general nucleic acid binding activity, with a strong preference for guanyl and uridyl-rich RNA sequences, as well as for single-stranded and double-stranded DNA. The functional significance of this affinity for nucleic acids remains unclear. However, based on the established association of 69KD with the Sm core domain of snRNPs in vivo, these motifs might help mediate 69KD binding to snRNPs or be involved in some, as yet, unknown aspect of RNA metabolism. Consistent with both possibilities, 69KD is detected within typical snRNP containing subnuclear structures referred to as speckles, and is also more widely distributed throughout the nucleoplasm, as observed for many hnRNP proteins.

Amino Acid Sequence↗
PubMed1996

Endocrine stress reaction to surgery in brain-dead organ donors.

We studied the course of plasma levels of the stress markers adrenocorticotropic hormone (ACTH), cortisol, human growth hormone (h-GH), beta-endorphin, and prolactin during retrieval surgery in eleven brain-dead organ donors scheduled for multiple organ explantation. Donors were divided into two groups according to hemodynamic stability. Hormones demonstrated a great variability in plasma levels and in the pattern of reaction, revealing a different degree of remaining pituitary function. Beta-Endorphin was the only stress hormone that showed a response to surgical stimuli in six patients. Only three of them developed a concomitant rise in ACTH. Cortisol, prolactin, and h-GH plasma levels did not change during the observation period. In the three cases with a slight elevation in ACTH, no subsequent change in cortisol was detectable. Beta-Endorphin showed greater variability and a tendency to higher levels in the group presenting with a higher arterial pressure, which resulted in a significant difference (P < 0.005) when distributions were compared using the Mann-Whitney U-test. No correlation was found between hypotensive episodes and deficiencies of other stress hormones. We conclude that pituitary function varies considerably in brain-dead organ donors without demonstrating a correlation to the onset of hypotension. Thus, we feel no need for a substitution treatment with any of the hormones investigated prior to organ explanation.

Adrenocorticotropic Hormone↗
PubMed1996

[Long-term outcome of conservative or surgical therapy of anterior cruciate ligament rupture].

The treatment of anterior cruciate ligament (ACL) rupture continues to be a controversial subject. This study was undertaken to compare long-term results of different therapy regimens A total of 52 patients (mean age: 34.7 +/- 3.2 years) who underwent ACL reconstruction using the central one third of the patellar tendon and 32 patients (mean age: 38.3 +/- 5.2 years) treated conservatively were evaluated 5-7 years clinically, radiologically and with respect to their sports activities. In all, 25% of the patients operated on subjectively rated their knees as "excellent", 40.4% as "very good", 22.2% "good", 12.5% "fair" and 0% as "poor". The ratings for the conservatively treated group were: 12.9%, 19.4%, 29%, 25.8% and 12.5%, respectively. The results of the OAK score were significantly better for the surgically treated group (87.5 +/- 7.1 points compared with 77.1 +/- 13.4). An increasing number of degenerative changes were found on radiographs in both groups at follow-up as compared with their pre-injury status.

Adult↗
PubMed1996

A comparison of sevoflurance to halothane in paediatric surgical patients: results of a multicentre international study.

Induction, emergence and recovery characteristics were compared during sevoflurane or halothane anaesthetic in a large (428) multicentre, international study of children undergoing elective inpatient surgical procedures. Two hundred and fourteen children in each group underwent inhalation induction with nitrous oxide/oxygen and sevoflurane or halothane. Incremental doses of either study drug were added until loss of eyelash reflex was achieved. Steady state concentrations of anaesthesia were maintained until the end of surgery when anaesthetic agents were terminated simultaneously. Time variables were recorded for induction, emergence and the first need for analgesia in the recovery room. In addition, in 86 of the children in both groups, venous blood samples were drawn for plasma fluoride levels during and after surgery. There was a trend toward smoother induction (induction of anaesthesia without coughing, breath holding, excitement laryngospasm, bronchospasm, increased secretion, and vomiting) in the sevoflurane group with faster induction (2.1 min vs 2.9 min, P = 0.037) and rapid emergence times (10.3 min vs 13.9 min, P = 0.003). Among the children given sevoflurane, 2% developed bradycardia compared with 11% in the halothane group. Postoperatively, 46% of the children in the halothane group developed nausea and or vomiting versus 31% in the sevoflurane group (P = 0.002). Two children in the halothane group developed cardiac dysrhythmia and were dropped from the study. In addition, a child in the halothane group developed malignant hyperthermia, received dantrolene, and had an uneventful recovery. Mean maximum inorganic fluoride concentration was 18.3 microM.l-1. The fluoride concentrations peaked within one h of termination of sevoflurane anaesthetic and returned rapidly to baseline within 48 h. This study suggests that sevoflurane may be the drug of choice for the anaesthetic management of children.

Adolescent↗
PubMed1995

Assembly, nuclear import and function of U7 snRNPs studied by microinjection of synthetic U7 RNA into Xenopus oocytes.

In Xenopus oocytes in vitro transcribed mouse U7 RNA is assembled into small nuclear ribonucleoproteins (snRNPs) that are functional in histone RNA 3' processing. If the special Sm binding site of U7 (AAUUUGUCUAG, U7 Sm WT) is converted into the canonical Sm sequence derived from the major snRNAs (AAUUUUUGGAG, U7 Sm OPT) the RNA assembles into a particle which accumulates more efficiently in the nucleus, but which is non-functional. U7 RNA with a heavily mutated Sm binding site (AACGCGUCAUG, U7 Sm MUT) is deficient in nuclear accumulation and function. By UV cross-linking U7 Sm WT RNA can be linked to three proteins, i.e. the common snRNP proteins G and B/B' and an apparently U7-specific protein of 40 kDa. As a result of altering the Sm binding site, U7 Sm OPT RNA cannot be cross-linked to the 40 kDa protein and no cross-links are obtained with U7 Sm MUT RNA. The fact that the Sm site also interacts with at least one U7-specific protein is so far unique to U7 RNA and may provide an explanation for the atypical sequence of this site. All described RNA-protein interactions, including that with the 40 kDa protein, already occur in the cytoplasm. An additional cytoplasmic photoadduct obtained with U7 Sm WT and U7 Sm OPT, but not U7 Sm MUT, RNAs is indicative of a protein of 60-80 kDa. The m7G cap structure of U7 Sm WT and U7 Sm OPT RNA becomes hypermethylated. However, the 3mG cap enhances, but is not required for, nuclear accumulation. Finally, U7 Sm WT RNA is functional in histone RNA processing even when bearing an ApppG cap.

Animals↗
PubMed1995

T cell lines recognizing the 70-kD protein of U1 small nuclear ribonucleoprotein (U1snRNP).

In sera of patients with mixed connective tissue disease (MCTD) high titres of IgG autoantibodies to U1snRNP-specific proteins (70 kD, A, C) are found, suggesting an antigen-driven and T-cell-dependent process. In order to establish U1snRNP-specific T cell lines we cultured under various culture conditions mononuclear cells from MCTD patients and healthy donors with a highly purified UsnRNP preparation from HeLa cells. Nine T cell lines were established by limiting dilution cloning from two MCTD patients and five T cell lines from a healthy individual. All T cell lines expressed the TCR alpha beta/CD3 complex. Surprisingly, most of the T cells lines exhibited the CD8 phenotype. Irrespective of this phenotype, all T cell lines showed a proliferative response to an N-terminal part (aa 51-195) of recombinant U1-specific 70-kD protein. One CD8+ T cell clone exhibited cytotoxic activity against an autologous B cell line pulsed with snRNP or recombinant fragments (aa 51-95 and aa 51-88). Interestingly, two T cell lines proliferated in response to four recombinant polypeptides representing different parts of the U1snRNP 70-kD protein. Since regions of sequence homology are distributed over the 70-kD molecule, it is suggested that conserved motifs may be recognized by the T cell lines.

Adult↗
PubMed1994

A 69-kD protein that associates reversibly with the Sm core domain of several spliceosomal snRNP species.

The biogenesis of the spliceosomal small nuclear ribonucleoproteins (snRNPs) U1, U2, U4, and U5 involves: (a) migration of the snRNA molecules from the nucleus to the cytoplasm; (b) assembly of a group of common proteins (Sm proteins) and their binding to a region on the snRNAs called the Sm-binding site; and (c) translocation of the RNP back to the nucleus. A first prerequisite for understanding the assembly pathway and nuclear transport of the snRNPs in more detail is the knowledge of all the snRNP proteins that play essential roles in these processes. We have recently observed a previously undetected 69-kD protein in 12S U1 snRNPs isolated from HeLa nuclear extracts under non-denaturing conditions that is clearly distinct from the U1-70K protein. The following evidence indicates that the 69-kD protein is a common, rather than a U1-specific, protein, possibly associating with the snRNP core particles by protein-protein interaction. (a) Antibodies raised against the 69-kD protein, which did not cross-react with any of the Sm proteins B'-G, precipitated not only U1 snRNPs, but also the other spliceosomal snRNPs U2, U4/U6 and U5, albeit to a lower extent. (b) U1, U2, and U5 core RNP particles reconstituted in vitro contain the 69-kD protein. (c) Xenopus laevis oocytes contain an immunologically related homologue of the human 69-kD protein. When U1 snRNA as well as a mutant U1 snRNA, that can bind the Sm core proteins but lacks the capacity to bind the U1-specific proteins 70K, A, and C, were injected into Xenopus oocytes to allow assembly in vivo, they were recognized by antibodies specific against the 69-kD protein in the ooplasm and in the nucleus. The 69-kD protein is under-represented, if present at all, in purified 17S U2 and in 25S [U4/U6.U5] tri-snRNPs, isolated from HeLa nuclear extracts. Our results are consistent with the working hypothesis that this protein may either play a role in the cytoplasmic assembly of the core domain of the snRNPs and/or in the nuclear transport of the snRNPs. After transport of the snRNPs into the nucleus, it may dissociate from the particles as for example in the case of the 17S U2 or the 25S [U4/U6.U5] tri-snRNP, which bind more than 10 different snRNP specific proteins each in the nucleus.

Animals↗
PubMed1994

Characterization of an HLA-DR4-restricted T cell clone recognizing a protein moiety of small nuclear ribonucleoproteins (UsnRNP).

In sera of patients with mixed connective tissue disease (MCTD, Sharp Syndrome) high titres of IgG autoantibodies to U1snRNP-specific proteins are found. The isolated occurrence of these autoantibodies is highly associated with the HLA-DR4 haplotype. snRNP-specific T cells are supposed to be involved in this autoantibody production. To address this question we cultured mononuclear cells from MCTD patients and healthy donors with a highly purified UsnRNP preparation from HeLa cells using bulk or limiting dilution cultures. Secondary responses to snRNP were detected only rarely with T cell lines from two patients and two controls, and turned out to be unstable during further expansion. One T cell line derived from a healthy individual retained its snRNP reactivity upon limiting dilution cloning and could be characterized in detail. The CD4+ T cell clone recognized native snRNP particles presented by monocytes in an HLA-DR4 (B1*0401)-restricted manner. Separation of the protein and RNA moieties of snRNP particles revealed that the T cell clone responded specifically to the protein fraction, but not to RNA and diverse control antigens. Sequencing of the T cell receptor alpha and beta chain cDNAs revealed that the clone used the V alpha 14.2 and V beta 14 elements. Upon antigen-specific and mitogenic stimulation the T cell clone showed a Th1-specific cytokine pattern, and did not provide helper activity for in vitro immunoglobulin production. This study demonstrate the presence of self-reactive snRNP-specific T cells in a healthy donor. The T cell clone may not represent a helper T cell for the formation of U1snRNP-specific autoantibodies.

Amino Acid Sequence↗
PubMed1993

Forced-air warming maintains intraoperative normothermia better than circulating-water mattresses.

The hypothesis that forced-air warming preserves core temperature better than circulating-water mattresses was tested in: (a) 16 adults undergoing major maxillofacial surgery, including radical node resection and flap reconstruction; (b) 53 adults undergoing hip arthroplasty, having approximately 25% of their body surface area available for warming; (c) 20 infants undergoing minor maxillofacial surgery; and (d) 10 young children undergoing pelvic or femoral osteotomies. Patients having each type of surgery were randomly assigned to forced-air warming (approximately 40 degrees C) or conductive warming using a full-length circulating-water mattress at 40 degrees C. Forced-air warming was applied to the legs of the adults undergoing maxillofacial surgery and to one arm, the shoulders, and the neck in the adults undergoing hip arthroplasty; a U-shaped, tubular forced-air cover was positioned around the pediatric patients. Core temperatures increased in all patients given forced-air warming and decreased or remained constant in those without active warming. Furthermore, we needed to decrease the temperature of the warmer from high to medium (approximately 37 degrees C) in most patients assigned to forced-air warming to prevent hyperthermia. After 15 h of anesthesia, rectal temperatures in the adults undergoing maxillofacial surgery were 3.4 degrees C higher in the forced-air group (P < 0.01). After 4 h of anesthesia, esophageal temperatures had increased 0.8 +/- 0.5 degrees C in the patients warmed with forced-air and decreased 0.8 +/- 0.3 degrees C in those warmed by circulating-water mattresses (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Are laser-resistant endotracheal tubes safe with the new holmium:YAG infrared laser?

Laser-induced ignition of the endotracheal tube is the most morbid event that may occur during laser surgery of the upper respiratory/digestive tract. The efficacy of two new laser-resistant endotracheal tubes, the Laser-Flex stainless steel tube by Mallinckrodt and the Laser-Shield II tube with teflon-aluminium-silicone coating by Xomed-Treace, was studied under exposure to a newly introduced pulsed infrared laser (holmium:YAG, lambda = 2120 nm) in an experimental setting. The time from the onset of exposure until tube perforation was recorded. Laser exposure was continued for up to 180 s unless tube ignition occurred. Temperature during the following 30 s laser application was measured close to the target zones. The irradiance level of the holmium:YAG laser was in the range required for photoablation and plasma formation and led to laser-induced tube ignition in both types of tube. The steel tube showed greater resistance to laser-induced wall damage than the teflon-aluminium silicone tube. The maximum temperature increase following laser exposure was moderate in both tubes; the mean rise of 10 degrees C for the Laser-Shield tube and 23 degrees C for the Mallinckrodt tube correlating with the physical effects of photoablation.

Aluminum↗
PubMed1993

[Pseudo-faulty location of a Swan-Ganz catheter in a persistent left superior vena cava].

The insertion of a Swan-Ganz catheter may cause various complications including intravascular malpositioning due to congenital anomalies of the large veins. A persistent left superior vena cava is the most frequent anomaly of the large vessels. It is usually diagnosed either as an incidental finding at autopsy or during X-ray imaging for confirming proper position of central venous and pulmonary catheters. The incidence of this condition based on autopsy series is approximately 0.3%. CASE REPORT. A 52-year-old patient was admitted to the surgical ICU with the diagnosis of acute pancreatitis. Because of haemodynamic instability, a pulmonary artery flotation catheter was inserted via the left subclavian vein without difficult. The chest radiograph showed the catheter along the left border of the heart going into the right pulmonary artery. An angiographic examination with bolus contrast injection confirmed a persistent left superior vena cava. CONCLUSION. This type of malposition calls for further detailed diagnosis of the vascular status, as the knowledge of accompanying congenital cardiovascular defects is essential for further invasive diagnostic and surgical procedures. The intensivist should be aware of its occurrence in order to not mistake catheters as being present in the arterial circulation or malpositioned outside the venous circulation.

Catheterization, Swan-Ganz↗