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Biomedical subjects

A Horn

Publications and source records attributed to A Horn.

At least 55 records · Page 3Linked to original sources
PubMed1996

Timing of tracheal intubation: monitoring the orbicularis oculi, the adductor pollicis or use a stopwatch?

The most suitable time for tracheal intubation, following vecuronium 0.1 mg kg-1, was estimated in 120 patients. The trachea was intubated at cessation of the visually observed response of the orbicularis oculi muscle to facial nerve stimulation (group 1; n = 30), or of the manually detected response of the adductor pollicis to ulnar nerve stimulation (group 2; n = 30), or after waiting 3 min (group 3; n = 30), or 4 min (group 4; n = 30). There were no significant differences in intubation scores between the four groups of patients. Loss of response to train-of-four stimulation occurred significantly sooner in group 1 (orbicularis oculi) than in group 2 (adductor pollicis) P = 0.021). However, intubating conditions were poor in four patients (14%) in group 1, compared with none in group 2 and one in groups 3 and 4, respectively. Thus, contrary to expectations, the cessation of the response of the orbicularis oculi muscle did not guarantee good or even satisfactory intubating conditions. The results suggest that in fit adult patients it is as good to wait 3 min after injection of vecuronium 0.1 mg kg-1 before tracheal intubation, as to use a nerve stimulator.

Adolescent↗
PubMed1996

[Psychosomatic aspects of patients with primary keratoconjunctivitis sicca].

PURPOSE: To evaluate the extent of psychosomatical complaints in patients with primary keratoconjunctivitis sicca (pKCS). METHODS: 20 patients (m:f = 1.19; mean age 49 +/- 7 years) with pKCS were rated according to the von Zerssen Symptom List (psychosomatical discomfort), the Maudsley Personality Inventory (MPI)-N (emotional status) and -E (extroverted-introverted) and to Beck Depression Inventory (BDI). 54 subjects (m:f = 35:17; mean age 46 +/- 17 years) without any ocular or general chronic disease were used as control group. RESULTS: In comparison to the control group the patients with pKCS showed significantly (p < 0.0001) more complaints (von Zerssen Symptom List), were more (p < 0.0001) emotionally unstable (MPI-N) and more (p < 0.0001) depressive (BDI). No group differences were found regarding extroversion-introversion (MPI-E). CONCLUSION: Our results demonstrate that many patients with pKCS showed psychological problems and disturbances. We therefore recommend an additional psychological treatment (e.g. autogenic training) for these patients to stabilize their emotional condition, which may even have a positive effect on their dry eye problems.

Adult↗
PubMed1996

Hormonal and metabolic responses to electrically induced cycling during epidural anesthesia in humans.

Hormonal and metabolic responses to electrically induced dynamic exercise were investigated in eight healthy young men with afferent neural influence from the legs blocked by epidural anesthesia (25 ml of 2% lidocaine) at L3-L4. This caused cutaneous sensory anesthesia below T8-T9 and complete paralysis of the legs. Cycling increased oxygen uptake to 1.90 +/- 0.13 (SE) l/min, and fatigue developed after 22.7 +/- 2.7 min. Compared with voluntary exercise at the same oxygen uptake and heart rate, concentrations of blood and muscle lactate (musculus vastus lateralis) as well as plasma potassium increased more while muscle glycogen decreased more during electrically induced exercise. Hepatic glucose production always rose during exercise. However, during involuntary exercise with sensory blockade, it did not match the rise in peripheral glucose uptake and plasma glucose decreased (P < 0.05). Plasma glycerol increased less in electrically induced vs. voluntary exercise, and free fatty acids and beta-hydroxybutyrate decreased only during electrically induced exercise. Epinephrine, growth hormone, adrenocorticotropic hormone, and cortisol levels were higher during involuntary vs. voluntary exercise (P < 0.05). In conclusion, neural and humoral mechanisms exert redundant control with regard to responses of catecholamines and pituitary hormones (growth hormone and adrenocorticotropic hormone). In contrast, neural input from motor centers and feedback from working muscle are important for glucose production and lipolysis during exercise in humans. Humoral feedback is apparently not sufficient to trigger normal mobilization of extramuscular fuel stores.

Adult↗
PubMed1995

Glycosylphosphatidylinositol-alkaline phosphatase from calf intestine as substrate for glycosylphosphatidylinositol-specific phospholipases--microassay using hydrophobic chromatography in pipet tips.

An electrophoretically homogeneous glycosylphosphatidylinositol- alkaline phosphatase fraction from calf intestine, obtained by hydrophobic chromatography, was used as "enzyme-labeled" substrate for testing phospholipase activity. The reaction products were separated by (i) hydrophobic chromatography in pipet tips and (ii) Triton X-114 phase partitioning. The chromatographic method presented permits high test frequencies, does not need temperature-controlled sample handling, and is only slightly disturbed by detergents, organic solvents, and proteins. The method was used to characterize phosphatidylinositol- specific phospholipase C from Bacillus cereus and phospholipase D from calf serum. Measurement of substrate hydrolysis by phospholipases is apparently linear to enzyme concentration and time. Relative activity of both enzymes is maximum at pH 6.5, corresponding to the optimal pH range found with other glycosylphosphatidylinositol substrates and phosphatidylinositol-specific phospholipases of other sources. Maximum activity of phospholipase C was found at 0.03% Triton X-100, 0.01% Brij 35, and 0.2% n-octylglucoside. The activity is not affected by Ca(2+), NaHCO(3), o-phenanthroline, or EDTA, increasingly inhibited by MgCl(2), MnCl(2), and ZnCl(2), and slightly activated by Na+ and K+. Calf serum phospholipase D shows maximum activity at 0.05% Triton X-100, 0.02% Brij 35, and 0.4% n-octylglucoside. The apparent Km values for phospholipase C (12.25 micron) and phospholipase D (4.94 micron) found with glycosylphosphatidylinositol-alkaline phosphatase are compared with values published for other glycosylphosphatidylinositol substrates.

Alkaline Phosphatase↗
PubMed1995

Characterization of the interaction of alkaline phosphatase with an activity inhibiting monoclonal antibody by progress curve analysis.

Using the enzyme activity inhibiting monoclonal antibody IB 10B8 against alkaline phosphatase of calf intestine (AP), the interaction of a macromolecular antigen with the antibody was studied with different reaction conditions and with different conformations of the antigen, i.e. using (i) different pH values, (ii) different temperatures, (iii) different substrate saturation of the enzyme, (iv) different glycosylphosphatidyl-AP (GPI-AP) aggregates, and (v) membrane-bound species. In the case of antibody excess and negligible substrate consumption enzymic product formation proceeds according to [P] = a + b x t - c x exp(-d x t). By direct progress curve fitting and secondary data evaluation using nonlinear regression, omitting numerical derivation and graphic techniques, kinetic constants of the immune reaction have been estimated. The method does not require any artificial labelling nor any separation of bound and free entities. (i) Upon increasing pH from 9.8 to 11.0, the dissociation constant of the enzyme-antibody complex is increased strongly, mainly due to the decreasing association rate constant. (ii) A temperature increase from 25 degrees C to 37 degrees C produces a marked increase of both the association and dissociation rate constant. (iii) To differentiate between the interaction of the antibody with the free (E) and substrate-bound (ES) enzyme, experiments were done at different substrate concentrations. The results were fitted to a model allowing determination of association and dissociation rate constants of the free and substrate-bound enzyme. The inverse variation of association and dissociation rate constants caused by substrate binding produces a marked increase of the dissociation constant of the antibody-enzyme complex. The antibody-bound enzyme shows a nearly three-fold higher Km value and a six-fold lower catalytic constant as compared to the free enzyme. (iv) Investigations of the interaction of the antibody with anchorless AP, different hydrophobic aggregates of purified GPI-AP (fractions II-V). (v) Membrane-bound GPI-AP show that the epitopes of all species are fully accessible to the antibody and not cryptic. Surprisingly the insertion of the GPI-moiety into the membrane and the aggregation of the different GPI-AP fractions II-V seem to improve antibody binding. Such improvement of binding was not found in control experiments with Fab, indicating only for the bivalent antibody a stronger interaction with the multivalent antigen than with the monovalent antigen.

Alkaline Phosphatase↗
PubMed1995

Low molecular weight heparin started before surgery as prophylaxis against deep vein thrombosis: 2500 versus 5000 XaI units in 2070 patients.

The optimal administration regimens of low molecular weight heparins (LMWHs) have not yet been established. The aim of this study was to compare the efficacy and safety of 2500 and 5000 XaI units of the LMWH dalteparin in patients undergoing elective general surgery for malignant and benign abdominal disease. Prophylaxis was started in the evening before surgery and given once-daily every evening thereafter. The study was designed as a prospective, randomized, double-blind, multicentre trial. Some 66.4 per cent of patients were operated on for a malignant disorder. The primary endpoint was deep vein thrombosis (DVT) detected with the fibrinogen uptake test. Bleeding complications were recorded and classified. Analysis was made both on an intention to treat basis and in patients given correct prophylaxis (86.3 per cent). A total of 2097 patients were randomized and 27 excluded after randomization. A technically correct fibrinogen uptake test was obtained in 1957 patients. The incidence of DVT was significantly lower in patients given 5000 XaI units, this being true for both correct prophylaxis (6.8 versus 13.1 per cent, P < 0.001), on an intention to treat basis (6.6 versus 12.7 per cent, P < 0.001), and in patients with malignant disease (8.5 versus 14.9 per cent, P < 0.001). Sixty-seven patients (3.2 per cent) died within 30 days with no difference between the groups. There were two cases of fatal pulmonary embolism. The frequency of bleeding complications in the whole series was higher in patients randomized to 5000 XaI units (4.7 versus 2.7 per cent, P = 0.02), although this was not the case in those operated on for malignant disease (4.6 versus 3.6 per cent, P not significant). Dalteparin in the dose of 5000 XaI units started in the evening before surgery has a good thromboprophylactic effect in high-risk general surgery at the cost of a small bleeding risk. In patients with malignant disease there was no increased risk of bleeding. The overall frequency of fatal pulmonary embolism with dalteparin is extremely low, even in this high-risk group of patients.

Adult↗
PubMed1995

Effect of arm position on the effectiveness of perivascular axillary nerve block.

The influence of arm position on the effectiveness of perivascular axillary nerve block with a catheter was assessed prospectively in two groups of patients. Ninety patients were allocated randomly to receive 1% mepivacaine with adrenaline 40 ml with the arm either adducted or abducted. Radiographs were taken in 12 additional patients; six in each group immediately after injection of 2% mepivacaine 20 ml mixed with contrast agent 20 ml. There were no statistically significant differences in onset time, spread of analgesia, motor block or success rate between the two groups. Proximal flow of the local anaesthetic-contrast agent mixture was neither facilitated by arm adduction nor was it necessary for the development of a successful block.

Adolescent↗
PubMed1994

[Analysis of Ki-ras in pancreatic fluid aspirate. A new diagnostic possibility in investigation of pancreatic cancer].

The prognosis for pancreatic carcinoma is generally poor. The chance of survival could be improved if curative surgery were performed, but early diagnosis is then essential. Fine-needle aspiration cytology and endoscopic retrograde cholepancreaticography (ERCP) are widely used in order to obtain a precise diagnosis before laparotomy. In almost all patients with pancreatic adenocarcinomas, the oncogene Ki-ras is activated by point mutation. We describe a patient where conventional diagnostic procedures were inconclusive. However, DNA-analysis of aspirate from the pancreatic duct and from a pancreatic cyst showed activated Ki-ras oncogene. A malignant diagnosis was later confirmed. We propose that DNA-analyses of pancreatic fluid or tissues should be used whenever facing problems with an early and accurate diagnosis of pancreatic lesions.

Adenocarcinoma↗
PubMed1994

[Diagnosis and treatment with endoscopic retrograde cholangiopancreatography].

Endoscopic retrograde cholangiopancreatography (ERCP) was carried out for the first time in 1968. Five years later endoscopic sphincterotomy was performed. Since then both modalities have become established as necessary adjuncts in the diagnosis and treatment of patients with pathology in the bile duct or pancreas. The main indication is common bile duct stone, and as a consequence of this treatment fewer patients are now treated surgically. Patients with malignant bile duct obstruction can be given reasonable palliation of both jaundice and pruritus and therefore improved quality of life. Some reports indicate that endoscopic drainage may be useful for pancreatic stenosis. Complications are few, but vigilance and prompt treatment is necessary to keep morbidity at a minimum. Follow-up after several years shows that sphincterotomy is successful also in the long term. The authors discuss the present diagnostic and therapeutic situation.

Bile Duct Diseases↗
PubMed1994

Cardiovascular and ventilatory responses to electrically induced cycling with complete epidural anaesthesia in humans.

Cardiovascular and ventilatory responses to electrically induced dynamic exercise were investigated in eight healthy young males with afferent neural influence from the legs blocked by epidural anaesthesia (25 ml 2% lidocaine) at L3-L4. This caused cutaneous sensory anaesthesia below T8-T9 and complete paralysis of the legs. Cycling was performed for 22.7 +/- 2.7 min (mean, SE) (fatigue) and oxygen uptake (VO2) increased to 1.90 +/- 0.13 1 min-1. Compared with voluntary exercise at the same VO2, increases in heart rate (HR) (135 +/- 7 vs. 130 +/- 9 beats min-1) and cardiac output (16.9 +/- 1.1 vs. 17.3 +/- 0.91 min-1) were similar, and ventilation (54 +/- 5 vs. 45 +/- 41 min-1) was higher (P < 0.05). In contrast, the rise in mean arterial blood pressure during voluntary exercise (93 +/- 4 (rest) to 119 +/- 4 mmHg (exercise)) was not manifest during electrically induced exercise with epidural anaesthesia [93 +/- 3 (rest) to 95 +/- 5 mmHg (exercise)]. As there is ample evidence for similar cardiovascular and ventilatory responses to electrically induced and voluntary exercise (Strange et al. 1993), the present results support the fact that the neural input from working muscle is crucial for the normal blood pressure response to exercise. Other haemodynamic and/or humoral mechanisms must operate in a decisive manner in the control of HR, CO and VE during dynamic exercise with large muscle groups.

Adult↗
PubMed1994

Exercise-induced 31P-NMR metabolic response of human wrist flexor muscles during partial neuromuscular blockade.

The effects of a depolarizing (decamethonium, DECA) and a nondepolarizing neuromuscular blocking agent (vecuronium, VECU) on the phosphorus-31 nuclear magnetic resonance (31P-NMR)-detected metabolic response to muscle contractions were studied separately in six healthy untrained males. Subjects who showed splitting of the P(i) peak during graded rhythmic forearm exercise without the drugs were selected. It was found that both drugs abolished the P(i) peak splitting during exercise. Despite a similar reduction in phosphocreatine (PCr) during exercise with each drug, a smaller increase in P(i) was observed with DECA than with VECU (P < 0.05). End-exercise muscle pH was higher with DECA (6.93 +/- 0.07) than with VECU (6.79 +/- 0.11) (P < 0.05). The PCr and P(i) recovery was two- and threefold faster with DECA than with VECU, respectively (P < 0.05). On the basis of the concept that depolarizing and nondepolarizing agents have a preferential effect on fast- and slow-twitch muscle fibers, respectively, the present results support the hypothesis that the NMR-observed splitting of the P(i) peak reflects the metabolic differences between the two major fiber types of human skeletal muscle.

Adenosine Triphosphate↗
PubMed1994

Do acute side-effects during radiotherapy predict tumour response in rectal carcinoma?

Patients given preoperative radiotherapy (31.5 Gy in 18 fractions) in a prospective, randomized trial of presumably operable rectal adenocarcinoma, were examined for a possible relation between bowel toxicity manifested as diarrhoea, and tumour size in the operative specimen, in addition to recurrence rate. The group requiring drugs for diarrhoea had significantly smaller tumours at surgery (2.5 cm versus 3.5 cm, p < 0.05). Patients without significant radiation-induced diarrhoea had also more recurrences (37.5% against 14.3%, p = 0.01). The disease-specific survival rate was also significantly better (p = 0.02) at 1.5 and 10 years in patients with diarrhoea WHO grade 3 and 4; 89.5%, 75.9% and 65.1% compared to 83.5%, 49.3% and 44.4% in patients with no or minimal radiation-induced loose bowels. These results indicate that the reaction of the normal bowel to radiation may correlate to radiation sensitivity of tumours derived from the same tissue.

Adult↗
PubMed1994

Is the brush border membrane of the intestinal mucosa a generator of "chymosomes"?

1. The microvilli of enterocytes in calf intestine demonstrate high levels of vesiculation activity at the top and at the basal region. 2. The morphology of the vesicles associated with microvilli (100-500 nm diameter, unilamellar, few intramembraneous particles, high AP activity) is very similar to the morphology of vesicles found in the chyme. 3. Vesicles can be purified 6-10 fold from chyme of the calf intestine applying a Mg(++)-precipitation method, used for brush border membrane preparation. 4. Specific activities of alkaline phosphatase and disaccharidases were found to be much higher in chyme vesicles than in the mucosa. 5. Phospholipid content and phospholipid composition is in chyme vesicles different from brush border membrane vesicles. 6. The characterized chyme vesicles are referred to as chymosomes. We consider the mucosa as a large-scale generator of chymosomes, i.e. digestive enzymes bearing vesicles.

Alkaline Phosphatase↗
PubMed1993

Heterogeneity of glycosylphosphatidylinositol-anchored alkaline phosphatase of calf intestine.

A method is described for large-scale purification of glycosylphosphatidylinositol-anchored alkaline phosphatase from intestinal mucosa and chyme to homogeneity. Both enzyme preparations contain approximately 2 mol fatty acid/mol subunit and exhibit a very similar fatty acid composition with octadecanoate and hexadecanoate as prevalent components. No significant differences between native glycosylPtdIns-anchored and hydrophilic alkaline phosphatases from both sources were found regarding Km, Vmax, the type of inhibition and inhibition constants of the amino acids L-leucine, L-phenylalanine, and L-tryptophan. The purified enzymes of both sources yield diacylglycerol and phosphatidic acid, after treatment with phosphatidylinositol-specific phospholipase C (PtdIns-PLC) and glycosylphosphatidylinositol phospholipase D (PLD), respectively. Enzyme preparations of both sources appear as heterogeneous mixtures of five fractions separable by octyl-Sepharose chromatography. Fraction I corresponds to the anchorless enzyme, fractions II-V differ in their susceptibility to phospholipases. Fractions II and IV are completely split by PtdIns-PLC or PLD action, almost 50% of fraction III is split by PtdIns-PLC, while fraction V is resistant. The susceptibility of these two fractions toward the action of PLD is considerably higher. Fatty acid analysis yields molar ratios of fatty acids/alkaline phosphatase subunit of 1.78, 2.58, 2.24, and 3.37 for fractions II, III, IV, and V, respectively. Aggregates of glycosylPtdIns-anchored alkaline phosphatase of all fractions are seen in native PAGE in the presence of Triton X-100. By gel chromatography in the presence of Brij 35, fractions II-V form stable multiple aggregates of dimers and may bind different amounts of the detergent. These data, together with fatty acid analysis, can be interpreted by the following model. Fractions II and IV are tetramers and octamers with two molecules fatty acid/subunit. Fraction III is a tetramer, bearing one additional fatty acid molecule, localized on the dimer. Fraction V is an octamer, containing glycosylPtdIns-anchor molecules with three molecules fatty acids/anchor molecule. The additional fatty acid residue is possibly located on inositol and responsible for the reduced susceptibility to PtdIns-PLC. The similarity of all measured parameters of both enzymes suggests that the glycosylPtdIns-anchored alkaline phosphatase of the mucosa is released into the chyme without changing the anchor molecule constituents.

Alkaline Phosphatase↗
PubMed1993

Determination, purification, and characterization of alpha-NADH.

alpha-NADH can be determined in the presence of high concentrations of beta-NADH using anion exchange HPLC combined with oxidation of beta-NADH by lactate dehydrogenase. The method is suited for the detection of a large number of impurities. Residual absorption is a poor measure of alpha-NADH. By combination of preparative anion exchange chromatography and reversed-phase HPLC, alpha-NADH can be prepared with 95-98% purity starting from beta-NADH. Commercially available preparations contain only 80-90% alpha-NADH. The anomerization kinetics of alpha- and beta-NADH has been investigated at pH 7.0 and 7.3 taking into account the irreversible conversion reactions of alpha- and beta-NADH. The H+ ion activity related anomerization rate constants kappa 1 (alpha to beta) and kappa 2 (beta to alpha) have been found to be 170 and 29 M-1 s-1, respectively, at pH 7.0 and 192 and 36 M-1 s-1, respectively, at pH 7.3. The equilibrium constants kappa 1 /kappa 2 are 5.8 and 5.3 at pH 7.0 and pH 7.3, respectively. Absorption and fluorescence properties of alpha-NADH preparations have been determined newly. At 25 degrees C, maximum absorption was found at 260.1 and 346.6 nm, whereas at 37 degrees C the wavelengths were 260.1 and 345.3 nm. Maximum fluorescence excitation was found at 348 nm, and maximum emission was at 453 nm.

Anions↗
PubMed1993

Intra-arterial versus intravenous regional analgesia for hand surgery.

Twenty-six adult patients participated in this study of intra-arterial and intravenous regional analgesia. The radial or the brachial artery was cannulated in patients randomised to receive intra-arterial regional analgesia and a hand vein was cannulated in patients randomised to receive intravenous regional analgesia, with a 22-G cannula. A double cuffed tourniquet and Esmarch's bandage were used. Lignocaine 0.5%, (1.5 mg.kg-1 intra-arterially, and 3.0 mg.kg-1 intravenously) was injected over 3 min. There were two failures (one in each group). Intra-arterial injection of lignocaine was more painful than intravenous injection. Onset and offset of analgesia, surgical and tourniquet pain scores, motor blockade, and bruising after cannulations were similar. Surgical conditions were good in all patients having intra-arterial regional analgesia, fair and poor in five having intravenous regional analgesia (ns). Three of the intravenous regional analgesia patients had transient adverse affects after tourniquet release (ns). No permanent sequelae of cannulations were observed. It is concluded that intra-arterial regional analgesia with lignocaine 0.5%, 1.5 mg.kg-1 has similar onset, offset, quality, failure rate and patient acceptance, as intravenous regional analgesia with lignocaine 0.5%, 3.0 mg.kg-1.

Adult↗
PubMed1993

Multiwavelength photometry of thermochromic indicator solutions for temperature determination in multicuvettes.

If buffer/indicator systems are used as optical thermometers in multicuvettes, the temperature resolution is limited by errors of optical measurements produced mainly by variations of pathlength and blank transmittance of the wells. Theoretical and practical approaches show that, in multicuvettes, a between-well temperature resolution of < 0.05 degrees C can be achieved by multiwavelength photometry with use of the Tris/cresol red indicator system. Using up to three absorbances (A0, A1, A2) measured in the same well at different wavelengths for calculation of differences, quotients, and quotients of differences, we found the optimum temperature signal to be In(A1/A2), with equal-ranking absorbances changing with temperature in opposite directions. We have used the method successfully to measure the temperature profiles and temporal dynamics of temperatures at all positions in two types of multicuvettes under controlled conditions, or not controlled thermostatically.

Indicators and Reagents↗