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Biomedical subjects

A Horn

Publications and source records attributed to A Horn.

At least 37 records · Page 2Linked to original sources
PubMed2000

Gel chromatographic characterization of the hydrophobic interaction of glycosylphosphatidylinositol-alkaline phosphatase with detergents.

The interaction of a glycosylphosphatidylinositol (GPI) protein with different detergents was studied for the first time with a purified protein. Four differently hydrophobic fractions of GPI-alkaline phosphatase (GPI-AP) from calf intestine were used as model proteins. The mode of interaction was determined by investigating (i) the self-aggregation behaviour of the GPI-AP fractions, (ii) the interference of detergents with GPI-AP binding to octyl-Sepharose, and (iii) the elution of GPI-AP bound to octyl-Sepharose. It was shown that polyoxyethylene-type detergents surprisingly interact much stronger than n-octylglucoside with GPI-AP, which is in contrast to the known behaviour of GPI-proteins in natural membranes. Gel filtration chromatography of Triton X-100 at concentrations above the critical micellar concentration yields three different micelle species with apparent molecular weights of about 166, 54, and 16 kDa. GPI-AP fraction II, which is shown to bear only one anchor per dimer, does not bind to any of these micelles. We demonstrate that a complex is formed containing about 150 Triton X-100 molecules and about 4700 molecules of water per molecule of GPI-AP dimer. The experimental findings are in accordance with a simple geometrical model based on the physical data of fatty acids and the arrangement, mean size, and shape of Triton X-100 molecules.

1-Propanol↗
PubMed1999

[Disabilities and handicaps due to hip fractures in the elderly].

OBJECTIVE: to examine mortality, mobility, pain, institutionalization rates six month after hip fractures. DESIGN: observational study, non-selected consecutive patients, time-set protocol. SETTING: urban area (population n = 116,5000), five hospitals. PARTICIPANTS: hip fracture patients (n = 214), age 65 + years (mean 82.4 years). MEASUREMENTS: age, gender, prefracture status, operative procedures, complications, comorbidity, cognition (MMSE), depression (GDS), fear of falling, ADL (Barthel) and mobility and pain status (SAHFE protocol). RESULTS: the incidence for this age group was 636.9/100,000, 31.8% were institutionalized elderly. 84% of the patients were female. Pre-existing comorbidity showed a high prevalence of neurodegenerative (cognitive deficits 53. 6%, Parkinson's disease/syndrome 11.2%) and cerebrovascular diseases (16.8%). Six month postfracture, the mortality was 17.6%. From those surviving 76.2% did walk indoors, 58.5% did also walk outdoors. Independent to dress were 54.6%. Severe pain was reported by 10.2%, whereas 36.9% described no pain. The institutionalization rate at six month was 19.0%. CONCLUSIONS: the study showed considerable mortality, a significant loss in function and social disintegration. Considerable differences were observed for subgroups of patients. Future treatment should focus on risk stratification and include postdischarge training programs. Moreover, preventive strategies should be implemented for high risk groups, such as ambulating patients with a history of stroke. Parkinson's disease and syndrome, dementia and nursing home residents.

Activities of Daily Living↗
PubMed1999

Glycosylphosphatidylinositol-specific phospholipase D in blood serum: is the liver the only source of the enzyme?

In cases of systemic inflammatory response syndrome, sepsis, and septic shock, the activity of glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD) in serum amounts to 20 to 25% of the activity found in a healthy control group. The activity of serum GPI-PLD is positively correlated with inflammatory markers and counts of monocytes and stab cells (bands) and negatively correlated with polymorphonuclear neutrophils and lymphocytes in severe diseases. This indicates a yet unknown involvement of the inflammatory system in GPI-PLD liberation and suggests that the liver is not the only source of the plasma enzyme. Plasma was shown to contain an effective inhibitor of GPI-PLD which is soluble in organic solvents. Its concentration in capillary plasma is 20-fold higher than in venous plasma. To find possible other sources of plasma GPI-PLD besides the liver, the GPI-degrading activity was measured in different organs of the rat. Product formation was analysed using [125I]TID-labeled GPI-AP.

Alkaline Phosphatase↗
PubMed1999

Cocaine-induced mood disorder: prevalence rates and psychiatric symptoms in an outpatient cocaine-dependent sample.

This paper attempts to examine and compare prevalence rates and symptom patterns of DSM substance-induced and other mood disorders. 243 cocaine-dependent outpatients with cocaine-induced mood disorder (CIMD), other mood disorders, or no mood disorder were compared on measures of psychiatric symptoms. The prevalence rate for CIMD was 12% at baseline. Introduction of the DSM-IV diagnosis of CIMD did not substantially affect rates of the other depressive disorders. Patients with CIMD had symptom severity levels between those of patients with and without a mood disorder. These findings suggest some validity for the new DSM-IV diagnosis of CIMD, but also suggest that it requires further specification and replication.

Adult↗
PubMed1999

The safety and effectiveness of remifentanil as an adjunct sedative for regional anesthesia.

UNLABELLED: We assessed the sedative potential of continuous infusions of remifentanil with a validated composite alertness scale in 160 patients (ASA physical status I or II) undergoing hip replacement surgery with spinal block (n = 61) or hand surgery using brachial plexus block (n = 93). They were randomized to receive one of the following initial dose regimens in double-blinded fashion: placebo or 0.04, 0.07, or 0.1 microg x kg(-1) x min(-1) remifentanil subsequently titrated to effect. Additional midazolam IV was allowed for adequate sedation as required. The combined analysis of both surgery groups revealed a dose-related increase in achievement of sedation level > or =2 within 15 min of the start of the study drug infusion; all remifentanil dose comparisons with placebo reached significance (P < 0.001). The remifentanil 50% effective dose for a composite sedation level > or =2 within 15 min of the start of drug infusion was estimated as 0.043 microg x kg(-1) x min(-1) (95% confidence interval 0.01, 0.059). The requirement for midazolam decreased with increasing remifentanil dose compared with placebo (P < 0.001). The median time to return to alertness after the end of infusion was 10-12 min in the remifentanil groups and 5 min in the placebo group. Significant incidences of nausea, pruritus, sweating, and respiratory depression were reported during remifentanil infusions compared with placebo. The data suggest that remifentanil may be useful for supplementation of regional anesthesia, provided that ventilation is carefully monitored. IMPLICATIONS: In this dose-finding, placebo-controlled study, remifentanil infusions were used to provide sedation during spinal and brachial plexus regional anesthesia. The 50% effective dose for achievement of sedation was 0.043 microg x kg(-1) x min(-1). Return to alertness occurred after 10-12 min (median time). Remifentanil infusions can be used to supplement regional anesthesia, but this requires careful monitoring of ventilation.

Adjuvants, Anesthesia↗
PubMed1999

Cerebral metabolic response to submaximal exercise.

We studied cerebral oxygenation and metabolism during submaximal cycling in 12 subjects. At two work rates, middle cerebral artery blood velocity increased from 62 +/- 3 to 63 +/- 3 and 70 +/- 5 cm/s as did cerebral oxygenation determined by near-infrared spectroscopy. Oxyhemoglobin increased by 10 +/- 3 and 25 +/- 3 micromol/l (P < 0. 01), and there was no significant change in brain norepinephrine spillover. The arterial-to-internal-jugular-venous (a-v) difference for O(2) decreased at low-intensity exercise (from 3.1 +/- 0.1 to 2. 9 +/- 0.1 mmol/l; P < 0.05) and recovered at moderate exercise (to 3. 3 +/- 0.1 mmol/l). The profile for glucose was similar: its a-v difference tended to decrease at low-intensity exercise (from 0.55 +/- 0.05 to 0.50 +/- 0.02 mmol/l) and increased during moderate exercise (to 0.64 +/- 0.04 mmol/l; P < 0.05). Thus the molar ratio (a-v difference, O(2) to glucose) did not change significantly. However, when the a-v difference for lactate (0.02 +/- 0.03 to 0.18 +/- 0.04 mmol/l) was taken into account, the O(2)-to-carbohydrate ratio decreased (from 6.1 +/- 0.4 to 4.7 +/- 0.3; P < 0.05). The enhanced cerebral oxygenation suggests that, during exercise, cerebral blood flow increases in excess of the O(2) demand. Yet it seems that during exercise not all carbohydrate taken up by the brain is oxidized, as brain lactate metabolism appears to lower the balance of O(2)-to-carbohydrate uptake.

Adult↗
PubMed1999

Middle cerebral artery flow velocity and cerebral oxygenation during abdominal aortic surgery.

Cerebral perfusion was evaluated in twelve patients undergoing elective infra-renal abdominal aortic aneurysmectomy by transcranial Doppler ultrasonography-determined middle cerebral artery mean flow velocity, near-infrared spectroscopy-assessed cerebral oxygen saturation and systemic haemodynamic variables. The middle cerebral artery mean flow velocity and cerebral oxygen saturation decreased during cross-clamping of the aorta, and both increased upon declamping of the aorta with the oxygen saturation change lagging behind the change in the flow velocity. The changes in cerebral flow velocity and oxygen saturation paralleled the deviations in cardiac output and end-tidal carbon dioxide tension.

Aged↗
PubMed1999

Single-session alcohol sclerotherapy in symptomatic benign hepatic cysts. Long-term results.

PURPOSE: To evaluate the long-term results of single-session alcohol sclerotherapy of symptomatic benign liver cysts. MATERIAL AND METHODS: 23 cysts in 19 patients were treated by single-session percutaneous catheterization and injection of 96% ethanol. Evaluation of long-term results was possible in 11 cysts (volume 200-2,700 ml, mean 1,317 ml) in 11 patients. Time of observation was 12-67 months, mean 38.3 months. RESULTS: The reduction of volume was 93-100% (mean 98%). The re-accumulation of fluid after therapy seen in 9 patients proved to be transitory. Except for pain there were no complications. CONCLUSION: Single-session sclerotherapy resulted in satisfactory cyst volume reduction in all 11 long-term follow-up patients.

Adult↗
PubMed1999

Pain management of pancreatic cancer.

Quality of life is receiving increasing attention as a criterion for the assessment of treatment, not least for surgery, in pancreatic cancer. In exocrine pancreatic cancer there are three main symptoms that must be dealt with: pain, loss of weight and jaundice. All of them seriously impair quality of life, but most often pain is the most feared by the patients. Despite this, the intensity and the quality of the pain is all too often only scantly described. In 85 consecutive patients with newly diagnosed pancreatic cancer we have prospectively registered the quality and quantity of their pain and correlated it to tumor and patient characteristics. It was found that about one fourth of the patients were totally pain free and half of all suffered a pain described by two or less on a Visual Analogue Scale. Only one in ten had severe pain. Although more and more patients were treated with morphine, it was still about one third of all patients that had no or only little pain in the last part of their life. Pain had a strong correlation to survival. This may be due to secondary effects like depressing the mood of the patient and reducing the food intake, but is probably more often a reflection of that generalized cancer induces more pain. Analgesic drugs are the cornerstone of the pharmacologic management of pain due to pancreatic cancer. A significant part of the patients do well with only paracetamol and nonsteroidal antiinflammatory agents. Combining these agents with narcotic analgesics can enhance pain control while lessening the dose of narcotics. A wide range of narcotics are available as well as different modes for delivery: regular pills, slow release forms, injections, subcutaneous injections, epidural etc. Each patient's pain management should be individualized, based on the intensity of pain, the type of pain and the side effects. It is essential not only to describe the medication, but also to follow-up the development of the pain and the patient's total experience of the situation. As an alternative to narcotics, plexus celiac blocks have been used with somewhat different result; in the hands of the experts the percutaneous approach is usually sufficient, but in the hands of other also poor results are reported. During the last years thoracoscopic splanchnicectomy has been tried as a complement giving long-standing pain relief with little or no side effects in the majority of patients. With this approach the sympathetic fibers lead by the symphathetic chain and further by the nervus splanchnicus major, minor and minors are divided. The denervation is easily done and can be performed bilateraly in one seance. This method will probably be used more often as the technique is now well described.

Humans↗
PubMed1998

Newborn screening for galactosemia: ultramicro assay for galactose-1-phosphate-uridyltransferase activity.

An enzymatically optimized, miniaturized (20 microl) fluorimetric assay of galactose-1-phosphate-uridyltransferase using dried blood spots for newborn screening is presented. The Beutler reaction principle has been adapted to the microtiter plate technology and acetone/methanol was used for complete deproteinization. A special ultramicro multiwell screening plate resistant to organic solvents has been developed and employed. The assay is simple, sensitive and inexpensive, due to small reagent volumes and the low prices of ultramicro screening plates. The reaction is linear with galactose-1-phosphate-uridyltransferase activity up to 120 min of incubation time. It shows low imprecision and good correlation to a quantitative validation test. For standardization the use of plate means or medians of activity or fluorescence values is proposed. Individual blank measurement prevents false negative assessments.

Fluorometry↗
PubMed1998

Studies on human porin. XVI: Polyamines reduce the voltage dependence of human VDAC in planar lipid bilayers--spermine and spermidine inducing asymmetric voltage gating on the channel.

We present the first data on the effects of polyamines on human VDAC. Purified VDAC in lipid bilayers shows lowered voltage dependence whenever putrescine, cadaverine, spermine, spermidine, or the histamine releaser Compound 48/80, respectively, are applied. Only spermine and spermidine induce an asymmetric reaction on the channel. However, we state a groupwise different reaction of polyamines, which are organic polycations, on human porin.

Humans↗
PubMed1998

Studies on human porin XVIII: the multicompartment effector ruthenium red reduces the voltage dependence of human VDAC in planar lipid bilayers.

The initial data on the effect of ruthenium red on mature human type-1 VDAC are presented. Highly enriched human type-1 porin in planar lipid bilayers shows lowered voltage-dependence whenever a commercially available ruthenium red preparation is applied. The hexavalent polycationic dye ruthenium red affects different functions in varying cell compartments. Concerning the plasma membrane of cells the actual data, together with our former measurements on the interaction of VDAC and the polycationic synthetic polyamine Compound 48/80, refer to a second VDAC opener, which is relevant for studies on the stimulation of exocytotic processes of different cell types.

Humans↗
PubMed1998

Total plasma antioxidant capacity is not always decreased in sepsis.

OBJECTIVE: To compare total plasma antioxidant capacity and selected individual antioxidants in patients with varying degrees of severity of sepsis. DESIGN: A prospective, observational, consecutive case study. SETTING: A 16-bed intensive care unit (ICU) in a university teaching hospital. INTERVENTIONS: None. PATIENTS: Forty-six healthy controls, ten ICU patients, nine patients with systemic inflammatory response syndrome (SIRS), 11 septic patients, and 14 septic shock patients. Plasma was obtained in healthy patients scheduled for minor surgery immediately before anesthesia and in ICU patients within 24 hrs of admittance to the unit or diagnosis of SIRS, sepsis, or septic shock. MEASUREMENTS AND MAIN RESULTS: Using the total peroxyl radical trapping method, we found plasma antioxidant capacity to be lower in septic patients but higher in septic shock patients, as compared with controls. Bilirubin was the greatest contributor to the increase with shock, followed by uric acid. Neopterin also correlated with the peroxyl radical trapping antioxidant parameter values. CONCLUSION: Although total plasma antioxidant capacity is decreased from normal levels in septic patients, an increase in some oxidants contributes to an increased total antioxidant capacity in septic shock patients.

Adolescent↗
PubMed1997

Single-session alcohol sclerotherapy in benign symptomatic hepatic cysts.

PURPOSE: To evaluate the results of single-session alcohol sclerotherapy in benign symptomatic liver cysts. MATERIAL AND METHODS: Ten cysts (volume 200-4,800 ml) in 10 patients were treated by percutaneous catheterization and injection of 96% ethanol at a dose of 10% of the cyst volume but never more than 100 ml. The treatment was applied for a maximum of 20 min, after which the alcohol and catheter were removed. RESULTS: A satisfactory reduction in cyst volume was achieved in all patients. In 8 patients there was a re-accumulation of fluid during the first period after therapy, followed by a significant reduction in volume on later follow-up examinations. Except for pain, there were no complications. CONCLUSION: Sclerotherapy as a single-session procedure resulted in a significant reduction in cyst volume in all 10 patients. The postprocedural re-accumulation of fluid seen in 8 patients proved to be temporary. It was not necessary to repeat the sclerotherapy procedure in any patient.

Adult↗
PubMed1997

Reactive pleuropericarditis following laparoscopic fundoplication.

Postpericardiotomy syndrome is not uncommon following cardiac surgery. The syndrome is characterized by fever, chest pain, leucocytosis, and signs of pericardial and pleural effusions. A patient with similar symptoms after laparoscopic treatment of reflux esophagitis is reported. Antibiotic treatment had no effect on a suspected bacteriological infection. There was a dramatic clinical response to corticosteroid treatment. The etiology and pathogenesis of the syndrome are discussed.

Adult↗
PubMed1996

Microheterogeneity of the hydrophobic and hydrophilic part of the glycosylphosphatidylinositol anchor of alkaline phosphatase from calf intestine.

Digestion of calf intestine alkaline phosphatase with pronase and subsequent dephosphorylation of the released peptidyl-(Etn-P)2-glycosyl-PtdIns with HF generated 8 glycosyl-Ins species the largest of which (G1 and G2) have the following proposed structures: [sequence: see text] G3 and G5 are lower homologues of G1 and G2, respectively, being one alpha 1-2 linked mannopyranosyl residue shorter. G4 is analogous to G2 lacking the N-acetylgalactosaminyl residue and G6 is the next lower homologue of G4. Most of G4 and G6 occur substituted with a palmitoyl (G4, G6) or a myristoyl residue (G6) probably attached to the inositol moiety. Thus, the basic ManxGlc-Ins species are either substituted with an N-acetylgalactosaminyl residue or a fatty acid ester. The structures were deduced from compositional analysis, molecular-mass determination by matrix-assisted laser desorption MS, sequential hydrolysis with appropriate exoglycosidases and treatment with CrO3. Purification of the glycosylinositol species was achieved by a novel reverse-phase HPLC technique using fluorescent fluoren-9-yl-methoxy-carbonyl (Fmoc) derivatives. These stable derivatives were susceptible to hydrolysis with exoglycosidases which allowed sequential cleavages to be carried out and kinetics to be followed at the picomole level. We observed recently that native alkaline phosphatase separates on octyl-Sepharose into four distinct fractions of increasing hydrophobicity (F1-F4). Here we show that all four fractions contain G1-G6. The acylated species G4 and G6 were restricted to F2 and F4 which had been shown earlier to contain, on average, 2.5 and 3 fatty acid residues/subunit, respectively. In all four fractions the diradylglycerol moiety was predominantly diacylglycerol, alkylacylglycerol being less than 10% which is in contrast to most glycosyl-PtdIns--anchored proteins of mammalian origin.

Acetylgalactosamine↗