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Biomedical subjects

A Bach

Publications and source records attributed to A Bach.

At least 91 records · Page 5Linked to original sources
PubMed1997

Semiquantitative analysis of intrahepatic cytokine mRNAs in chronic hepatitis C.

In order to characterize intrahepatic cytokine production, the mRNA levels of interleukin (IL)-2, -4, and -10 and interferon (IFN)-gamma were semiquantitatively determined by reverse-transcription competitive polymerase chain reaction in liver specimens from patients with chronic hepatitis C (n = 23), chronic hepatitis B (n = 9), or primary biliary cirrhosis (n = 12) and normal liver (control) specimens (n = 12). IL-4 mRNA was undetectable. Similar IL-10 mRNA levels were detected in all samples studied, including the controls. Mean IFN-gamma and IL-2 mRNA levels were elevated in chronic inflammatory liver disease. IL-2 mRNA levels were similar in all 3 patient groups, but intrahepatic IFN-gamma mRNA levels were significantly higher in chronic hepatitis C than in chronic hepatitis B or primary biliary cirrhosis patients. This predominance of IFN-gamma may indicate a lower susceptibility of hepatitis C virus to the antiviral effects of this cytokine. The presence of IL-10 in normal liver may impair the induction of antiviral immune responses.

Actins↗
PubMed1997

Continuous versus intermittent thermodilution cardiac output measurement during orthotopic liver transplantation.

We evaluated intermittent and continuous thermodilution cardiac output data in 12 patients undergoing orthotopic liver transplantation. Measurements were performed at 16 predefined time points between induction of anaesthesia and 3 h after reperfusion of the liver graft. Cardiac output measurements yielded 192 data pairs (intermittent cardiac output range: 1.8-18.9 l.min-1, continuous cardiac output range: 3.3-20.0 l.min-1). During most of the procedure the correlation between intermittent and continuous cardiac output measurements was significant (r = 0.87, p < 0.0001), accompanied with a bias of -0.240 l.min-1 and a degree of precision of 1.789 l.min-1 (< 10.0 l.min-1:1.137 l.min-1, > or = 10.0 l.min-1:2.220 l.min-1). However, in the early phases after caval clamping and after reperfusion, accuracy was not acceptable. Only during these phases did the difference between the mean values of pulmonary artery blood temperature and rectal temperature increase (after caval clamping) or decrease (after reperfusion). In conclusion, despite acceptable levels of accuracy and precision between intermittent and continuous cardiac output measurement under stable conditions, both methods showed markedly decreased accuracy and precision in the early phases after caval clamping and after reperfusion, possibly owing to increased thermal noise.

Adult↗
PubMed1997

Caudal clonidine and bupivacaine for combined epidural and general anaesthesia in children.

BACKGROUND: Clonidine produces analgesia by actions on alpha 2-adrenoceptors and enhances both sensory and motor blockade from epidural injection of local anaesthetics. Low-dose clonidine has been used so far for caudal injection in children. Our aim was to study the perioperative effects of high-dose caudal clonidine when added to low concentration of bupivacaine for combined epidural and general anaesthesia in children. METHODS: After induction of general anaesthesia caudal block was performed either with 1 ml.kg-1 bupivacaine 0.175% with the addition of clonidine 5 micrograms.kg-1 (n = 20), or with 1 ml.kg-1 bupivacaine 0.175% (n = 20). The intraoperative anaesthetic requirements, the perioperative haemodynamic effects, respiratory rate, sedation score, postoperative pain scores and side effects were assessed by a blinded observer. A patient-controlled analgesia system was used for postoperative pain relief. The quality of postoperative pain relief was assessed using Smiley's pain analogue scale. RESULTS: Intraoperative haemodynamic responses did not differ between the groups. However, during emergence from general anaesthesia children in the clonidine group had significantly lower heart rates and blood pressure compared to children in the control group. In addition, heart rates and blood pressures were also lower in the clonidine group in the early postoperative period (P < 0.05). Postoperative analgesia was significantly better in the clonidine group as evidenced by the total number of requests (3 vs 12, P < 0.05) and the total amount of tramadol (20.5 mg vs 72.8 mg, P < 0.05) administered. The duration of the caudal analgesia was significantly longer in the clonidine group (20.9 +/- 7.4 h vs 14.4 +/- 10.9 h, P < 0.05). CONCLUSION: Our results suggest that caudal clonidine 5 micrograms.kg-1 enhances and prolongs caudal blockade with bupivacaine (1.175% in children. It also blocks sympathoadrenergic responses during emergence from anaesthesia. Sedation and cardiovascular effects are observed up to 3 h into the postoperative period.

Adrenergic alpha-Agonists↗
PubMed1997

Alternative techniques for measuring nutrient digestion in ruminants.

Because in vivo measurement of nutrient digestion in the rumen and small intestine requires ruminally and intestinally cannulated animals that are expensive, labor-intensive, and subject to error associated with markers and inherent animal variation, alternative techniques have been developed. Researchers have proposed various in situ or in vitro procedures for estimating ruminal and small intestinal nutrient digestion. This review summarizes these alternative techniques.

Animals↗
PubMed1996

Effect of endotoxemia on intestinal villus microcirculation in rats.

Intestinal mucosal hypoperfusion with subsequent ischemia during endotoxemia might cause a breakdown of the gut barrier with translocation of bacteria and their toxins into the systemic circulation, thus maintaining a "gut-derived" septic state. The aim of this study was to investigate the influence of endotoxin on the microcirculation of intestinal villi, which represent the most vulnerable part of the mucosa. The changes in blood flow and in the diameters of the central villus arterioles located in the distal ileum were monitored in control rats without lipopolysaccharide (LPS) exposure (n=7), and in rats receiving 1.5 mg/kg b.w. LPS (n=7) or 15 mg/kg b.w. LPS (n=7) over 60 min. The blood flow and the arteriolar diameters were determined using in vivo videomicroscopy at baseline, and 60 min and 120 min later. In control animals, no change in blood flow and arteriolar diameters were observed during the entire experiment. Administration of 1.5 mg/kg b.w. LPS reduced the blood flow to 69.5 +/- 9.0% of the baseline value at the end of the study period. This decrease in blood flow was associated with a decrease in the villus arteriolar diameters by 17.4 +/- 2.5% from the baseline values. In animals exposed to 15 mg/kg b.w. LPS, the decrease in villus blood flow at 60 min was 64.8 +/- 10.9% of baseline, and at 120 min 66.9 +/- 12.6% of baseline. The diameters of the villus arterioles were reduced by 11.5 +/- 2.4% and 15.1 +/- 1.7%, respectively. In the control group and in the 1.5-mg/kg LPS group, the mean arterial blood pressure did not change during the entire study period. In the 15-mg/kg LPS group, the mean arterial pressure tended to decrease after 60 min. These data suggest a reduction of villus blood flow due to vasoconstriction in the central villus arterioles during normotensive endotoxmia, which might represent the mechanism for the mucosal ischemia observed in critically ill patients.

Animals↗
PubMed1996

Retention of the antibiotic teicoplanin on a hydromer-coated central venous catheter to prevent bacterial colonization in postoperative surgical patients.

OBJECTIVE: Antibiotic-coated intravascular catheters may be an effective means of decreasing bacterial colonization and subsequent catheter-related infection. The present study was designed to investigate the retention of the antibiotic teicoplanin on a hydromer-coated intravenous catheter and the effect of this antibiotic coating on catheter bacterial colonization. DESIGN: A prospective, randomized pilot study. SETTING: Operating rooms (ORs) and an intensive care unit (ICU) at a university hospital. PATIENTS: A consecutive group of 20 male patients undergoing major abdominal surgery. INTERVENTIONS: Control (C; n = 10) or teicoplanin-coated (T; n = 10) single-lumen central venous catheters were inserted before surgery in the OR. Catheters were withdrawn at the discretion of the physicians in the ICU after various periods. MEASUREMENTS: The teicoplanin content of the catheter material was assessed using a bioassay with Bacillus subtilis after complete elution of the antibiotic from the catheter. Bacterial colonization was measured using a quantitative culture technique after the catheter lumen had been flushed and the catheter segments sonicated. MAIN RESULTS: Nearly three-quarters of the initial teicoplanin coating (374 +/- 103 micrograms; mean +/- SD) were released during the first day of catheterization, and after 36 h of intravenous catheterization, no antibiotic was retained on the catheter. No significant difference could be found either in the incidence of bacterial colonization between test (n = 3) and control (n = 4) catheters or in the number of colony-forming units (CFU) on the catheter segments (T, 263 +/- 104 CFU/cm; C, 372 +/- 294 CFU/cm; mean +/- SEM). CONCLUSION: The retention of teicoplanin antibiotic coating on hydromer catheters is only short term if catheters are inserted intravenously. This may limit clinical antibacterial efficacy.

Anti-Bacterial Agents↗
PubMed1996

Effect of low-dose dopamine on intestinal villus microcirculation during normotensive endotoxaemia in rats.

Hypoperfusion of the gut mucosa is thought to be a factor in the development of gut barrier failure during sepsis and septic shock. Dopamine stimulates DA-1 receptors which mediate regional vasodilatation in the gut. Therefore, we have investigated the effect of low-dose dopamine (3 micrograms kg-1 min-1) on the intestinal villus microcirculation during endotoxaemia in a rat model of normotensive endotoxaemia, using in vivo videomicroscopy. Blood flow in and the diameters of central villus arterioles were measured before, immediately after and 60 min after a 1-h continuous infusion of endotoxin 1.5 mg/kg body weight. After baseline measurements were obtained, rats received either an infusion of 0.9% saline (group A; n = 7) or a volume-equivalent infusion of dopamine 3 micrograms kg-1 min-1 (group B; n = 7) throughout the study. Control animals (group C; n = 7) received no endotoxin or dopamine. In group A, villus blood flow (mean baseline 8.4 (SEM 0.9) nl min-1) decreased by 29.7 (8.9)% to 5.9 (0.9) nl min-1 immediately after endotoxin challenge and by a total of 43.1 (7.3)% to 4.7 (0.7) nl min-1 after another 60 min. Simultaneously, villus arteriolar diameters decreased from 7.8 (0.2) to 6.9 (0.3) microns and to 6.5 (0.3) microns, respectively. In group B, villus blood flow (baseline 8.7 (0.4) nl min-1) was unchanged immediately after the 1-h infusion of endotoxin (8.3 (0.4) nl min-1). However, another 60 min later blood flow decreased by 28.8 (8.0)% to 6.1 (0.7) nl min-1. In contrast with group A, the diameters of the central villus arterioles were unchanged despite administration of endotoxin (7.9 (0.2) microns; 8.1 (0.4) microns; 8.2 (0.5) microns). In group C, there were no changes in villus blood flow or arteriolar diameters throughout the study. Our results indicated that low-dose dopamine did not prevent, but delayed and attenuated, the decrease in intestinal villus blood during normotensive endotoxaemia.

Animals↗
PubMed1996

Retention of antibacterial activity and bacterial colonization of antiseptic-bonded central venous catheters.

We determined how long antiseptic impregnation with silver sulphadiazine and chlorhexidine (SCC) on polyurethane central venous double- or triple-lumen catheters is retained in vivo. A total of 116 antiseptic catheters were tested for antibacterial activity in an in-vitro bioassay after various periods of iv catheterization. Segments from the subcutaneous (sc) and intravenous (iv) portions of the catheters were cultured. The results of test antiseptic catheters were compared with those from 117 noncoated control (c) catheters. Retention of antibacterial activity followed an exponential curve and lasted for up to 520 h after catheter insertion. Significant differences (P = 0.0001) between SSC and C catheters were noticed with regard to the quantitative level of bacterial colonization (SSC-sc 87 +/- 34 vs C-sc 584 +/- 122; SSC-iv 52 +/- 17 vs C-iv 286 +/- 57; all values are given as mean cfu +/- S.E.M.), and the frequency of bacterial colonization (SSC-sc 20.7% vs C-sc 38.5%, P = 0.0047; SSC-iv 18.1% vs C-iv 30.8%, P = 0.0361). There was no significant difference between the incidence of catheter-related bacteraemia in the test (n = 0) and control groups (n = 3) (P = 0.2573). Further prospective studies are required to delineate the role of antiseptic catheters in preventing catheter-related infections.

Bacteremia↗
PubMed1996

Chemistry, nutritional sources, tissue distribution and metabolism of vitamin K with special reference to bone health.

Vitamin K occurs in nature as a series of compounds with a common 2-methyl- 1,4 naphthoquinone nucleus and differing isoprenoid side chains at the 3 position. They comprise a single major plant form, phylloquinone with a phytyl side chain and a family of bacterially synthesized menaquinones (MKs) with multiprenyl side chains. The major dietary source to humans is phylloquinone for which the chief food contributors are green, leafy vegetables followed by certain vegetable oils (soybean, rapeseed and olive oils). Recent analyses by high pressure liquid chromatography are now providing a wide-ranging database of phylloquinone in foods. Menaquinones are found in moderate concentrations in only a few foods such as cheeses (MK-8 and MK-9). A wider spectrum of MKs is synthesized by the gut microflora, and their intestinal absorption probably accounts for most of the hepatic stores, particularly those with very long side chains (MKs-10--13) synthesized by members of the genus Bacteroides. The site of absorption of floral MKs is not known, but reasonable concentrations are found in the terminal ileum where bile salt-mediated absorption is possible. Both phylloquinone and menaquinones are bioactive in hepatic gamma-carboxylation but long-chain MKs are less well absorbed. Liver stores of vitamin K are relatively small and predominantly MKs-7--13. The hepatic reserves of phylloquinone (approximately 10% of the total) are labile and turn over at a faster rate than menaquinones. Trabecular and cortical bone appear to contain substantial concentrations of both phylloquinone and menaquinones. A majority (approximately 60-70%) of the daily dietary intake of phylloquinone is lost to the body by excretion, which emphasizes the need for a continuous dietary supply to maintain tissue reserves.

Animals↗
PubMed1996

Dopexamine maintains intestinal villus blood flow during endotoxemia in rats.

OBJECTIVE: To determine the influence of dopexamine, a synthetic catecholamine ligand for dopaminergic and beta 2-adrenergic receptors, on alterations of the intestinal villus microcirculation in a model of normotensive endotoxemia. DESIGN: Randomized, controlled trial. SETTING: Experimental laboratory. SUBJECTS: Twenty-one male Wistar rats. INTERVENTIONS: Rats were treated with a continuous infusion of dopexamine (2.5 micrograms/kg/min; N = 7; group A) or 0.9% saline (n = 7; group B) during a study period of 120 mins. Both groups were given endotoxin (Escherichia coli lipopolysaccharide; 1.5 mg/kg Iv) over 60 mins. Animals in the control group (n = 7; group C) received a volume-equivalent infusion of 0.9% saline. Total volume substitution in all groups was 15 mL/kg/hr. MEASUREMENTS AND MAIN RESULTS: Blood flow in the intestinal villi of the distal ileum was determined using in vivo videomicroscopy at baseline, and 60 and 120 mins after the endotoxin challenge. These blood flow determinations were done by an observer who was unaware of the previous treatment of the animals. In addition, mean arterial pressure was monitored at baseline, and 15, 30, 45, 60, 75, 90, 105, and 120 mins later. The administration of 1.5 mg/kg endotoxin alone (group B) resulted in a reduction of the intestinal villus blood flow to 74.8 +/- 9.5% of baseline after 60 mins, and to 61.1 +/- 8.5% of baseline after 120 mins (baseline: 7.4 +/- 0.6 nL/min; 60 mins: 5.3 +/- 0.8 nL/min; 120 mins: 4.4 +/- 0.5 nL/min; p < .05). This reduction of blood flow was associated with a decrease in the arteriolar diameters by 13.8 +/- 2.5% after 60 mins, and by 17.1 +/- 4.3% after 120 mins (p < .05 vs. baseline). In contrast, villus blood flow in the dopexamine group (group A) did not show statistically significant changes during the entire study period, despite the administration of endotoxin (baseline: 8.2 +/- 0.6 nL/min; 60 mins: 7.3 +/- 0.8 nL/min; 120 mins: 7.8 +/- 0.5 nL/min). No vasoconstriction of the villus arterioles was noted in this group. In control animals (group C), the blood flow (baseline: 8.1 +/- 1.6 nL/min; 60 mins: 7.6 +/- 1.4 nL/min: 120 mins: 7.8 +/- 1.4 nL/min) and the arteriolar diameters remained unchanged throughout the observation period. Mean arterial pressure did not differ between groups: it remained unaltered in all groups during the entire study period. CONCLUSIONS: Dopexamine maintains intestinal villus arterial perfusion and prevents the vasoconstriction in villus arterioles during early normotensive endotoxemia. Therefore, further studies in critically ill patients will have to determine whether the early prophylactic use of dopexamine can limit ischemia and prevent the development of multiple organ failure.

Adrenergic beta-Agonists↗
PubMed1996

Infectious risks associated with the use of propofol.

BACKGROUND: Investigations of the Centers for Disease Control into postoperative infections have implicated extrinsically contaminated propofol. METHODS: To evaluate the infectious risk associated with intravenous anaesthetic agents, we surveyed the literature from 1971 to 1995 using the Medline database. Papers covering infections related to intravenous anaesthetic agents were included. RESULTS: The review of the literature on infections associated with propofol and other intravenous anaesthetics shows that this infectious risk is minimal and often caused by breakdowns in aseptic techniques. CONCLUSIONS: We conclude that, if standard hygienic precautions are taken, the risk of in-use contamination of intravenous anaesthetics is low. If strict hygienic guidelines are followed in handling propofol, this agent can be safely administered to patients.

Anesthetics, Intravenous↗
PubMed1996

Recovery of psychomotor function following general anaesthesia in children: a comparison of propofol and thiopentone/halothane.

The present study was undertaken to compare immediate recovery and recovery of complex psychomotor function in 20 children (aged 6-12 years) following general anaesthesia with either thiopentone/halothane or propofol. Early recovery of psychomotor skills was significantly faster in the propofol group than in the thiopentone/halothane group. Compared to preanaesthesia baseline the sedation and cooperation scores, the reaction time to visual and auditory stimuli as well as the postbox test and the flicker fusion frequency were less impaired after propofol than after thiopentone/halothane anaesthesia up to 120 min postoperatively. In the propofol group most tests reached preanaesthesia levels after 120 min, while in the thiopentone/halothane group these levels were not reattained throughout the entire study period. The results indicate that the recovery of psychomotor function in paediatric patients following general anaesthesia with propofol is significantly faster than with thiopentone/halothane. This has important implications for parental satisfaction, the time over which patients need to be monitored in the recovery room and for the discharge criteria after daycase surgery.

Anesthesia Recovery Period↗
PubMed1996

[Documentation and therapeutic standards in anesthesia and intensive care medicine--means for quality assurance and cost control].

Patient data management in anaesthesia and intensive care should include besides medical data of individual patients economically important parameters, e.g. working time or cost of material. Integration of this data management system in the hospital information network enables case-oriented analyses for costs in relation to outcome. Standards of therapy including cost-benefit estimates may be an approach to improve the quality of care and to control the cost of medical care, in particular in the setting of teaching hospitals, avoiding erratic and costly orders by staff in training.

Anesthesia↗
PubMed1996

[Modular concept for quality in the hospital--"Heidelberg model"].

The Heidelberg University Hospital meets the standards required of medical services in terms of efficiency, optimizing procedures, cost-effectiveness, staff-satisfaction, and reducing infection rates etc., by implementing the Modular concept for quality within hospitals that has now proven its worth in practice. This concept combines a number of functional modules, including the hygiene, nursing, environment, and casualty modules, to name just four of them, within an overall framework incorporating guidelines focusing on quality, strategies, and management policies. Relevant European quality guidelines and the principles of Good Laboratory Practice (GLP), and Good Manufacturing Practice (GMP) are all taken into account to facilitate the required inter-hospital comparison with regard to continuous improvement of quality. It clearly demonstrates that expertise within the hospital and proven practicability in terms of numbers take definite precedence over theoretical approaches from outside experts.

Cost Control↗