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C Albers

Publications and source records attributed to C Albers.

At least 19 recordsLinked to original sources
PubMed2004

Development of a psilocin immunoassay for serum and blood samples.

After the immunisation of rabbits with a psilocin-specific immunogen, polyclonal antisera were obtained. With these antisera a competitive, heterogeneous radioimmunoassay for the detection of psilocin was developed. As tracer a derivative of psilocin was synthesised, which contained a tritiated CH(3) group. The antisera showed a specific reaction with psilocin. The cross-reactivity of structurally related endogenous substances like serotonin, tryptophan and tyrosine was below 0.01%. Also common drugs of abuse (Delta(9)-tetrahydrocannabinol, cocaine, morphine, amphetamine) showed negligible cross-reactivity (0.01-2%). Only tricyclic neuroleptics with a (dimethylamino)ethyl side-chain showed some cross-reactivity (20%). Spiked serum and blood samples were analysed with this new immunoassay and the results obtained were compared with the values measured with a validated GC-MS method.

Animals↗
PubMed1999

Differences in the sterol composition of dominant Antarctic zooplankton.

The composition of free sterols was determined in Antarctic zooplankton species with various feeding behaviors. In the Southern Ocean, the dominant calanoid copepods Calanoides acutus, Calanus propinquus, Metridia gerlachei, and Euchaeta antarctica were investigated during different seasons and compared with the euphausiids Euphausia superba, E. crystallorophias, and Thysanoessa macrura. In addition, the Arctic copepods Calanus hyperboreus, C. glacialis, and C. finmarchicus were studied for comparison. Analyses were performed using gas chromatography and mass spectrometry. The zooplankton species exhibited a simple sterol content of up to six sterols. In the copepods, cholest-5-en-3beta-ol (22.1 to 60.5%, range of sample means), cholesta-5,24-dien-3beta-ol (22.3 to 45.2%), and cholesta-5,22E-dien-3beta-ol (4.3 to 33.4%) contributed most, while in euphausiids the sterol composition was less complex with cholest-5-en-3beta-ol always accounting for more than 75% of the total. Although sterols are membrane constituents and are expected not to vary considerably, differences in the abundance of sterols were observed between the species and the seasons. In herbivorous copepods, cholesta-5,24-dien-3beta-ol increased by a factor of 1.5 to about 45% during the main feeding period in summer; this sterol is a metabolic precursor of cholest-5-en-3beta-ol in the process of the dealkylation of dietary C-24 alkylated phytosterols. Cholest-5-en-3beta-ol decreased by the same proportion. Omnivorous and carnivorous copepods showed average levels of cholesta-5,24-dien-3beta-ol below 25%. These changes in sterol composition between copepod species seem to reflect their different feeding modes.

Animals↗
PubMed1996

[Drugs and occupational accident].

In a case of a fatal occupational accident (construction worker, fall from roof, urine test positive for cocaine and THC, e.g. cannabis) the question arised to what extent those drug-related occupational accidents occur. In the literature only few cases, mainly dealing with cannabis influence, have been reported, however, a higher number is suspected. Cocaine and other stimulating drugs (amphetamine) are more often used to increase physical fitness. By direct or indirect interference with vigilance these compounds may provoke accidents. Due to the lack of a legal basis proving of the influence of drugs at the working place is still very limited, although highly sensitive chemical-toxicological assay procedures are available to detect even the chronic abuse (in hair). In the general conditions of accident insurances a compensation is excluded when alcohol is involved, but drugs are not mentioned. It is indeed difficult to establish a concentration limit for drugs like that existing for alcohol (1.1%). In each case the assay of the drug involved and exact knowledge of its specific effects is in an essential prerequisite to prove the causal relationship.

Accidents, Occupational↗
PubMed1996

Self-monitoring of triglycerides by type 2 diabetic patients: variability in fasting and postprandial levels.

Triglycerides are an important risk factor for coronary heart disease in Type 2 (non-insulin-dependent) diabetes mellitus. Although Type 2 diabetic patients have an exaggerated postprandial triglyceride response to a fat meal test, little is known about the variability of triglyceride concentrations in day-to-day life. We have studied the variability in triglyceride concentrations in 24 Type 2 diabetic patients over 6 months by having them record fasting and postprandial triglyceride concentrations at home using a Reflotron dry chemistry analyser. All patients were able to use the analyser effectively, with a correlation of 0.97 between patients' monthly Reflotron readings and those recorded by the laboratory. Over 1600 measurements were performed. The results demonstrate a large variation in both fasting (median 1.95 mmol l-1, range 0.8-6.7 mmol l-1) and postprandial triglyceride concentrations (median 2.68 mmol l-1, range 0.8-6.7 mmol l-1). This variation was accounted for by both a large intra- and inter-individual variation. Although there was a strong correlation overall between fasting and postprandial triglyceride concentrations r = 0.925 (p < 0.001), this did not apply on an individual basis. In conclusion, the large variability in triglyceride concentrations should be considered before introducing pharmacological therapy for hypertriglyceridaemia in Type 2 diabetes mellitus.

Body Mass Index↗
PubMed1995

Purification and characterization of an alpha-methylacyl-CoA racemase from human liver.

A specific racemase for alpha-methylacyl-CoAs, which had previously been studied in rat liver [W. Schmitz, R. Fingerhut, E. Conzelmann (1994) Eur. J. Biochem. 222, 313-323], has now been demonstrated also in human tissues. The human enzyme cross-reacts with a polyclonal antiserum against the rat liver racemase. The racemase was purified from human liver some 3600-fold. It is a monomer of 47 kDa with an isolectric point of pH 6.1 and is optimally active between pH 7-8. It acts only on coenzyme A thioesters, not on free fatty acids, and accepts as substrates a wide range of alpha-methylacyl-CoAs, including pristanoyl-CoA and trihydroxycoprostanoyl-CoA (an intermediate in bile acid synthesis), but neither 3-methyl-branched nor linear-chain acyl-CoAs. A clear difference in subcellular localization of the enzyme was found between humans and rats: the rat enzyme co-distributed exclusively with mitochondrial marker enzymes whereas in human cells, only 10-30% of the activity was found in mitochondria, the bulk activity was located in peroxisomes. Cells from patients with general deficiency of peroxisome assembly (Zellweger syndrome) showed strongly reduced racemase activity, with only the mitochondrial share being present while the peroxisomal form was absent.

Acyl Coenzyme A↗
PubMed1992

Exercise testing at 3 weeks, 6 weeks and 18 months after infarction and the outcome at 3 years in young patients (under 55 years).

To examine the prognostic value of routine postinfarction exercise tests in young patients, exercise tests were carried out at 3 and 6 weeks and 18 months after infarction in 149 patients aged under 55 years at the time of the index infarction. The patients also had coronary angiography and left ventriculography a mean of 3 months after infarction. Three years after infarction, only two of the 149 patients have died, reinfarction occurred in only seven (4.7%) patients; unstable angina in four (3%) patients and coronary artery surgery was needed in 31 (20.8%) patients; 16 in the first, 10 in the second, and 5 in the third year of follow-up. Angina on exercise testing at 6 weeks was the only variable with any predictive value. Eighteen (38%) of the 47 patients with, compared to 12 (11.8%) of the 102 patients without, angina on exercise testing at 6 weeks had coronary surgery (less than 0.001). None of the other exercise variables reliably predicted death, or other complications, including coronary surgery. Ten (13.8%) of the 75 patients excluded from the study died during follow-up; six of them within 6 weeks of infarction. Four (67%) of these patients were excluded from the study because of heart failure. Therefore, the 3-year outcome in young survivors of a myocardial infarction is good and is not reliably predicted by exercise testing at 3 and 6 weeks or 18 months.

Adult↗
PubMed1989

Exercise testing soon after myocardial infarction: its relation to course and outcome at one year in patients aged less than 55 years.

A consecutive series of 184 patients aged less than 55 years who had an acute myocardial infarction were enrolled in a study to examine outcome at one year. One hundred of these patients underwent a maximal exercise test six weeks after infarction to evaluate its ability to predict cardiac events. The in-hospital mortality for the series was 7.6% (14 deaths) and the one year mortality for the 170 survivors was 3.8% (seven deaths). During the exercise test 31 patients had angina and 21 had ST depression. During the one year follow up period 39 of 100 patients had angina on exertion, 15 patients underwent coronary artery surgery, three patients had a reinfarction, and one patient died. Angina during the exercise test but not ST segment depression during the exercise test predicted angina on exertion and the need for coronary artery surgery. In the year of follow up angina occurred during everyday exertion in 25 (81%) (95% confidence interval 62 to 92%) of the 31 patients who developed angina during the exercise test and in only 14 (20%) (95% confidence interval 12 to 32%) of 69 patients who did not, and coronary artery surgery was performed in 11 (35%) (95% confidence interval 19 to 54%) of the 31 patients with angina during the exercise test and only four (6%) (95% confidence interval 2 to 15%) of 69 patients without angina. The outcome after myocardial infarction in patients aged less than 55 years was good and the occurrence of angina, but not ST segment depression, during a maximal exercise test six weeks after infarction was an indication for further investigation.

Age Factors↗
PubMed1989

Cold intolerance in patients with angina pectoris: effect of nifedipine and propranolol.

Fifteen patients with chronic stable angina pectoris and a history of reduced exercise tolerance in cold weather (cold intolerance) underwent symptom limited treadmill exercise tests at 20 degrees C and 0 degrees C in a specially constructed cold chamber while taking no antianginal medication. Their mean time to onset of angina (5.8 v 4.2 min), to 1 mm ST depression (5.1 v 3.8 min), and to peak exercise (7.4 v 5.7 min) was significantly shorter on exercise at 0 degrees C than at 20 degrees C. The double product of heart rate and systolic blood pressure at each of these end points was the same in both exercise tests. Eight of these patients were treated with nifedipine 10 mg three times a day for two weeks and then with propranolol 40 mg three times a day for another two weeks. Repeat exercise testing was performed at the end of each two week treatment period. The mean time (SD) to peak exercise at the end of the nifedipine treatment period was 9.1 (2.0) min at 20 degrees C and 8.5 (2.3) min at 0 degrees C. The double product at peak exercise was the same for both exercise tests. At the end of the propranolol treatment period the mean time to peak exercise was significantly less at 0 degrees C (7.8 (2.6) min) than at 20 degrees C (8.9 (2.4) min). The double product at peak exercise was the same for both exercise tests but was significantly less than that on nifedipine. Cold intolerance was shown in patients with a positive history by symptom limited treadmill exercise testing at 0 degrees C. It persisted when they were treated with propranolol, albeit to a lesser extent, but not when they were treated with nifedipine.

Adult↗
PubMed1989

Age-dependent changes in volume and haemoglobin content of erythrocytes in the carp (Cyprinus carpio L.).

Carp erythrocytes were fractionated by angle-head centrifugation which yielded fractions with a linear increase in density. Haematological examinations revealed that the heavier red blood cells of carp had greater volumes (MCV), more haemoglobin (MCH) and higher haemoglobin concentrations (MCHC) than light ones. The same experiments with human red cell fractions yielded a decrease in MCV, constant MCH and an increase in MCHC. Haemoglobin content in individual erythrocytes was also determined by scanning stage absorbance cytophotometry to establish the frequency distribution of the cellular haemoglobin contents. In carp, the distribution was symmetrical with the means increasing with density. No such change with cell density was found in human erythrocytes. Both carp and human erythrocytes incorporated [2-14C]glycine in vitro. After gel filtration, radioactivity was detected in carp, but not in human, haemoglobin fractions. 14C was found in all three haemoglobin fractions, obtained by isoelectric focusing, and was present in the haem and in the globin. [2-14C]glycine-labelled erythrocytes were reinjected into chronically cannulated carp and followed in vivo for several months. With time, the main peak of scintillation counts shifted from red cell fractions of low to high density. This is considered as evidence that density and age of red cells in carp are positively correlated and that erythrocytes can synthesize haemoglobin while circulating in the peripheral blood.

Animals↗
PubMed1989

Glomerular and tubular membrane antigens reflecting cellular adaptation in human renal failure.

The excretion profiles of the following marker proteins of glomerular and tubular origin were studied in patients suffering from chronic renal disease (GN, N = 36, GFR: 8 to 120 ml/min/1.73 m2): angiotensinase A (ATA), a glomerular endothelial glycoprotein, tubular ala(-leu-gly)-amino-peptidase-M (APM), gamma-glutamyl transpeptidase (GGT), and the major brush border surface glycoprotein (SGP-antigen) of 240 kD. In addition, urinary excretion of proteins from kidney tissue and serum from 30 patients undergoing chronic hemodialysis (RCDT) were analyzed. Compared to the controls, ATA, APM and GGT activities were significantly higher in urine specimens of patients with GFR greater than 25 ml/min, whereas the urinary APM, GGT and SGP concentrations were decreased, and correlated with the GFR. Urinary GGT activity was negatively correlated with ATA activity but positively correlated with the decrease in GFR. Urine ATA activity of RCDT patients was higher compared to normal controls (2P = 0.001). Urinary excretion of serum proteins of RCDT patients, as assessed by SDS-polyacrylamide gel electrophoresis, disclosed heavy tubular proteinuria, indicating predominant tubular rather than glomerular alterations in handling of proteins. Histochemical evaluation of kidney sections from RCDT patients revealed clusters of hypertrophic nephrons with increased glomerular and tubular concentration of immunoreactive membrane proteins. However, there was a general decrease in renal cell-marker concentrations as observed by quantitative image analyses. These results indicate that renal injury is associated with a modulation in the synthesis of tubular and glomerular cell markers.

Adaptation, Physiological↗
PubMed1988

Effect of adrenaline and blood gas conditions on red cell volume and intra-erythrocytic electrolytes in the carp, Cyprinus carpio.

1. Carp, when subjected to air stress in vivo, developed a hypoxaemia associated with an acidosis due to elevation of PCO2 and arterial lactate content. Adrenaline and noradrenaline levels rose markedly, and the mean corpuscular haemoglobin concentration (MCHC in mmol Hb l-1 red blood cells) decreased, indicating swelling of the erythrocytes. 2. No effect of adrenaline could be observed in vitro after equilibration at normal pH and oxygenation level. 3. Simulation of air stress in vitro, by using hypercapnic hypoxia together with adrenaline, caused appreciable swelling of the red cells. The effect of adrenaline could be blocked by propranolol and was reversible when the blood gases were readjusted to normal values. Swelling due to hypercapnic hypoxia was not affected by propranolol. 4. At normal PO2, lowering pH by increasing PCO2 or adding HCl to the blood at PCO2 = 3.5 mmHg (1 mmHg = 133.3 Pa) both led to swelling of red cells; further swelling occurred when adrenaline was added. 5. At normal or even elevated intracellular pH, hypoxia led to red cell swelling; further swelling occurred when adrenaline was added. 6. The swelling of red cells under hypoxic and/or acidotic conditions (induced by either added HCl or increased PCO2) was associated with an increase in the intracellular K+, Na+ and Cl- levels, together with an increase in the Donnan distribution ratio of Cl-, rCl. delta K+:delta Na+ was 4:1. The swelling associated with the addition of adrenaline was also accompanied by an increase in K+, Na+, Cl- and rCl. In this case the ratio delta K+:delta Na+ was 1:2.4. 7. There was a correlation between the Donnan ratio, rCl, and the change in MCHC, even in those cases where extracellular and intracellular pH were above normal. In addition to pH and oxygen saturation, rCl should therefore be considered as a possible triggering factor for the action of adrenaline. 8. In addition to the increased catecholamine levels, stress during sampling may be inferred if low values of MCHC and high values of intraerythrocytic chloride and a high chloride distribution ratio, rCl, are found in whole blood.

Animals↗
PubMed1986

DMO-transport in human red blood cells.

The DMO (5,5-dimethyloxazolidine-2,4-dione) transport was studied in human red blood cells by measuring the 14C-DMO back exchange under self exchange conditions from 14C-DMO labeled cells at 0 degrees C. the unidirectional DMO-flux was linearly related to the DMO concentration up to approx. 100 mM. The unidirectional DMO-flux increases as pH is reduced. The DMO transport is not inhibited by anion transport inhibitors like DIDS, SITS, dipyridamole, phlorhizin, salicylate or butanol. A close correlation between the unidirectional DMO-flux and DMOH, the unionized form of DMO, has been observed suggesting that DMO is transported predominantly by nonionic diffusion. the permeability of DMOH is 9.5 X 10(-6) cm/s (0 degrees C) while the permeability of DMO- cannot be assessed from our data.

Adult↗
PubMed1986

Post-infarction exercise testing in patients under 55 years. Relation between ischaemic abnormalities and the extent of coronary artery disease.

Previous studies have suggested that the early post-infarction exercise test is useful in predicting the extent of coronary artery disease. The results of a heart rate limited exercise test three weeks after infarction and a symptom limited exercise test six weeks after infarction obtained by both standard lead electrocardiograms and 16 lead precordial maps were compared in 100 consecutive survivors of acute myocardial infarction under 55 years of age. Exercise tests were defined as being positive on the basis of angina, ST segment depression greater than or equal to 1 mm in any electrocardiogram lead, or exertional hypotension. Multivessel disease, that is two or three vessel disease, was present in 60 patients, and three vessel disease in 22 patients. The sensitivity, specificity, and predictive value for multivessel disease of the three week test were 38%, 83%, and 76% respectively; and results for the six week test were 55%, 75%, and 77% respectively. Only 32% of patients with three vessel disease were identified at the three week test, and 59% at the six week test. Significantly more patients with multivessel and three vessel disease were identified by the symptom limited six week test. Precordial mapping offered no advantages over the standard 12 lead electrocardiogram in either the identification of patients with multivessel disease or the prediction of the distribution of coronary artery disease. Angina pectoris during the exercise test at six weeks was the single most useful predictor of multivessel disease. Multivessel disease was found in 27 (87%) of the 31 patients with angina with or without ST depression during the test at six weeks compared with 33 (48%) of the 69 patients who did not have angina during the test at six weeks. Exercise testing in the early post-infarction period in patients under 55 years of age is of limited value in predicting the extent of coronary artery disease. It is, therefore, unreasonable to use such exercise tests to select patients for coronary arteriography after myocardial infarction. None the less angina pectoris occurring during a symptom limited exercise test six weeks after infarction is a strong predictor of multivessel disease, and coronary arteriography is recommended in these patients.

Adult↗
PubMed1985

H+ and Cl- ion equilibrium across the red cell membrane in the carp.

H2O and electrolyte distribution were studied in carp erythrocytes at various pH values achieved by CO2/O2 equilibration in vitro. Intracellular pH was measured by means of glass electrode and by DMO-14C. rH+, rCl- and rDMO- varied linearly and in a comparable manner with pHe. At pHe = 7.8, rH+, rCl- and rDMO- were 0.21, 0.29 and 0.30. rCl- and rDMO- were closely correlated and exhibited only minor differences. rH+ was closely correlated with rCl- and rDMO-, but was, however, significantly lower than rCl- or rDMO-. This difference is considered to be due to a systematic error of the glass electrode when used in highly concentrated protein solutions. The coulometric determination of chloride in packed red cells is shown to be highly susceptible to protein. The results are consistent with the assumption that H+ and Cl- ions are passively distributed across the red cell membrane.

Acid-Base Equilibrium↗
PubMed1985

Reciprocal ST depression in acute myocardial infarction.

ST segment depression in leads remote from those showing ST elevation during acute myocardial infarction has been attributed to benign electrical phenomena, distant myocardial ischaemia, or extensive myocardial damage. Eighty four consecutive survivors under 55 years of age with a first transmural myocardial infarction were studied. All patients had exercise tests six weeks after infarction and coronary angiography a mean of three months after infarction. Thirty eight (75%) of the 51 inferior and 19 (58%) of the 33 anterior infarcts showed reciprocal ST depression of greater than or equal to 1 mm during the acute phase. Ten (26%) of the 38 patients with inferior infarcts and reciprocal depression had ST depression in the same leads on exercise. There was concomitant disease of the left anterior descending artery in four (40%) of these 10 patients and in five (18%) of the 28 with inferior infarcts with reciprocal depression but without ST depression in the same leads on exercise. Five (26%) of the 19 patients with anterior infarcts with associated reciprocal depression and four of the 14 without reciprocal depression had important right coronary artery disease. In patients with inferior infarction important disease of the left anterior descending artery could not be predicted by ST depression in particular lead groups. Therefore reciprocal ST depression during acute myocardial infarction does not predict concomitant disease in the coronary artery supplying the reciprocal territory.

Arrhythmias, Cardiac↗
PubMed1984

Oxygen binding and acid base status of the blood from the freshwater turtle, Phrynops hilarii.

Oxygenation studies with the whole blood of Phrynops hilarii show a P50 of 38 torr at extracellular pH (pHe) of 7.4 which corresponds to an intracellular pH (pHi) of 7.05 at 25 degrees C. The blood CO2 Bohr effect was -0.56 when related to pHi. pHi is related to pHe by the following equation: pHi = 0.75.pHe + 1.54 (r = 0.99); pHi = 0.72. pHe + 1.72 (r = 0.96) at 10 and 25 degrees C respectively. Blood pHe, for 25 degrees C, was 7.519 +/- 0.254 (n = 6). Blood gas partial pressures were: pCO2 = 25.8 +/- 3.8 torr (n = 6); pO2 = 61.7 +/- 21.2 torr (n = 6). The major red cell phosphates, in mmole/l erythrocytes, n = 6, were: ATP (3.66 +/- 0.86); GTP (0.53 +/- 0.28); 2.3-DPG (0.32 +/- 0.12) and inorganic phosphates (2.00 +/- 0.35). The plasma inorganic ion composition, n = 6, was, in mEq/l: K+ (3.04 +/- 0.40); Na+ (148.4 +/- 12.6); Ca2+ (4.75 +/- 1.32); Cl- (106.6 +/- 5.0). Additional blood parameters of interest (n = 6) were: lactate (2.07 +/- 1.72 mM in plasma); erythrocytes/mm3 (416 X 10(3) +/- 4.6 X 10(3)); leucocytes/mm3 (44636 +/- 2618); haematocrit (%) (14.5 +/- 3.6); haemoglobin, g/dl (3.2 +/- 0.5); plasma protein g/dl (4.4 +/- 0.4); osmolarity (293 +/- 10 mOsm/l). The non-bicarbonate buffer value was -22.6 mmol/kg H2O/pH. For a constant CO2 content, delta pHe/delta t = 0.0141 +/- 0.002 (n = 18) and delta pHi/delta t = 0.0157 +/- 0.003 (n = 18).

Acid-Base Equilibrium↗