Concentration of 17 trace elements in serum and whole blood of plains viscachas (Lagostomus maximus) by ICP-MS, their reference ranges, and their relation to cataract.

The reference ranges of the trace elements Al, As, Be, B, Cd, Co, Cu, Fe, Mn, Mo, Ni, Pb, Li, Rb, Se, Sr, and Zn were determined by inductively coupled plasma-mass spectrometry (ICP-MS) in sera of a group of free-ranging plains viscachas of the pampa grasslands of Argentina. The values were compared with those of a small group of captive plains viscachas of the Zurich Zoo with diabetes and bilateral cataracts. In addition, a method for digestion of whole-blood samples is described for the trace element determination. Significant differences in the concentration of trace elements in the two groups of animals are discussed. No correlation was found between the levels of selenium and of other trace elements compared to the formation of cataracts.

Simultaneous measurement of the trace elements Al, As, B, Be, Cd, Co, Cu, Fe, Li, Mn, Mo, Ni, Rb, Se, Sr, and Zn in human serum and their reference ranges by ICP-MS.

The goal of this article was to establish reference ranges of the concentration of trace elements in human serum and to compare these results with those reported by other authors. We describe the sample preparation and measurement conditions that allow the rapid, precise, and accurate determination of Al, As, B, Be, Cd, Co, Cu, Fe, Li, Mn, Mo, Ni, Rb, Se, Sr, and Zn in human serum samples (n = 110) by inductively coupled plasma-mass spectrometry (ICP-MS). Accuracy and precision were determined by analyzing three reconstituted reference serum samples by comparison with other methods and by the standard addition procedure. The advantages of the ICP-MS method include short time of analysis of the elements mentioned, low detection limit, high precision, and high accuracy. Disadventages include a high risk of contamination due to the presence of some of the elements of interest in the environment, the relatively delicate sample handling, and the high cost of the equipment.

[Differential diagnostic considerations in CK-MB level increase]. / Differentialdiagnostische Uberlegungen zur CK-MB Erhöhung.

We present two patients who were hospitalized due to thrombo-embolic disease. Both patients had an increase in total creatine kinase activity with the creatine kinase MB fraction value exceeding the total creatine kinase activity. We determined that the high values for creatine kinase MB fraction in the immunoinhibition assay were due to the existence of macro creatine kinase type I in one patient and a highly elevated creatinine kinase BB fraction in the other patient. The patient with macro CK type I had ulcerative colitis and the other patient with elevated CK BB fraction was diagnosed with prostatic carcinoma.

Unexplained elevated serum hCG is associated with raised amniotic fluid erythropoietin levels in second-trimester pregnancies.

OBJECTIVE: This study was designed to investigate the association between the concentrations of maternal serum hCG and amniotic fluid erythropoietin during the second trimester of pregnancy. METHODS: In a prospective case-control study, 42 consecutive singleton pregnancies showing unexplained elevated serum hCG concentrations (>2.0 multiples of the median, MoM) in Down's syndrome screening and 27 control pregnant women undergoing midtrimester amniocentesis because of a previous cytogenetic abnormality were studied. RESULTS: The mean amniotic fluid erythropoietin concentration in the study group was 1.8 (range 0.61-8.7) MoM, whereas it was 1.1 (range 0.71-3. 96) MoM in the controls (p = 0.035). A significantly increasing relationship (p < 0.05) was found between the concentrations of maternal serum hCG and amniotic fluid erythropoietin. CONCLUSIONS: The results of the current study revealed in vivo the association between elevated hCG and amniotic fluid erythropoietin levels which, in turn, supports the concept of early placental damage. The underlying pathology seems to be sufficient to cause an erythroblastic response.

Direct determination of selenium and other trace elements in serum samples by ICP-MS.

Selenium belongs to a group of trace elements of special interest in biological samples for clinical diagnosis. Selenium has antioxidizing functions and is essential for providing the organism with triiodothyronine produced from thyroxine. Among several analytical techniques used to determine the Se concentration in serum, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) has been used in the past because of its high sensitivity. Interference problems originating from different ions on the major Se isotopes have been described to be a limiting factor for the direct determination of Se in these matrices. Standard addition calibration or isotope dilution is often required to overcome carbon-enhanced ionisation effects in biological sample matrices. In most cases, the typical serum sample volume which is available for the analysis is limited to 0.5 ml or less, making multiple sample preparation for standard addition calibration impractical. Isotope dilution requires enriched isotopes and substantial sample preparation. Furthermore, the approximate Se concentration in every sample has to be known to adjust the appropriate amount of spike to each sample. Matrix matching with methanol has been described to overcome ionisation effects but we found limiting factors of this application when other trace elements are also determined within one sample run. This paper describes an effective sample preparation method which allows the direct determination of Se in serum without limiting the analytical capabilities for the additional determination of Al, Cu, Ni, Co, Cd, Mn and Zn in a single sample run by ICP-MS. Optimization procedures are presented and results of the analysis of reference samples are discussed, with a comparison of more than 150 serum data with those obtained by the GF-AAS method.

The effect of intravenous iron on the reticulocyte response to recombinant human erythropoietin.

We studied the effect of intravenous (i.v.) administration of 200 mg of iron sucrose following an i.v. bolus injection of recombinant human erythropoietin (r-HuEPO; 300 U/kg body weight) in seven subjects and compared it with seven subjects treated with r-HuEPO alone. Reticulocytes, serum erythropoietin (EPO) and ferritin levels were studied at baseline and daily for the following 8 d. Use of i.v. iron abolished the marked reduction in serum ferritin observed with r-HuEPO administration. Although the total number of reticulocytes was not affected by i.v. iron administration, the reticulocyte Hb content and retHb (a measure in g/l of the Hb contained in all reticulocytes) were increased in the i.v. iron/r-HuEPO group compared with the group who received r-HuEPO alone. Therefore i.v. iron significantly potentiates the haemopoietic response to r-HuEPO in normal subjects.

Effects of intravenous and oral clonidine on hemodynamic and plasma-catecholamine response due to endotracheal intubation.

STUDY OBJECTIVE: To investigate the effects of intravenous (IV) versus oral clonidine on alterations of heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), and plasma-catecholamines due to endotracheal intubation. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: University hospital surgery operating room. PATIENTS: 33 ASA physical status I patients were randomly assigned to either receive clonidine 3 micrograms/kg IV immediately prior to anesthesia induction, clonidine 4 micrograms/kg orally 90 minutes prior to anesthesia induction, or placebo. INTERVENTIONS: Insertion of a 14 G cannula in a large cubital vein for the determination of plasma-catecholamines using local anesthesia. Insertion of a radial artery catheter for measuring blood pressure (BP) using local anesthesia. Transthoracic echocardiography determined CO. MEASUREMENTS AND MAIN RESULTS: Heart rate, MAP, CO, and plasma-catecholamine concentrations were measured. Measurements were performed prior to induction, during intubation, and 10 minutes after intubation. During endotracheal intubation, MAP was significantly lower in the IV clonidine group compared with the placebo and the oral clonidine groups. Cardiac output was significantly lower in the IV clonidine group only. In contrast to the placebo group, norepinephrine plasma concentrations did not increase in either clonidine group. Significant alterations of epinephrine plasma concentrations due to intubation were not observed in either group. Hemodynamics after intubation were not impaired by clonidine treatment. CONCLUSIONS: In conclusion, IV clonidine reduced stress response to endotracheal intubation compared with placebo. Oral clonidine at the dose used was less effective in blunting hemodynamic stress response than IV clonidine.

Lipofuscin in the retina: quantitative assay for an unprecedented autofluorescent compound (pyridinium bis-retinoid, A2-E) of ocular age pigment.

The pyridinium bis-retinoid, A2-E, has been discovered as one of the major autofluorescent components of retinal pigment epithelial lipofuscin. Due to its chemical characteristics, A2-E may contribute to cellular and molecular changes leading to age-related macular degeneration. Because A2-E is the first lipofuscin component that has been identified, purified, and its structure analysed, it represents an important marker molecule for studying lipofuscin formation under various conditions. In order to investigate the role of A2-E in ageing processes of the retinal pigment epithelium, we developed an HPLC assay for this compound using single wavelength UV-absorbance detection with continuous light emission. Standard A2-E was synthetized and purified by sequential TLC. In our assay, A2-E can be detected in amounts lower than 10 pmol. The assay has been applied to quantitative determination of A2-E amounts in albino rat eyes of different age groups. Our results demonstrate that there is a marked increase of A2-E levels in older animals. The method described is the first to allow quantification of this unusual retinoid from small amounts of biological samples.

Optimal timing of repeated rh-erythropoietin administration improves its effectiveness in stimulating erythropoiesis in healthy volunteers.

We studied the effect of recombinant human erythropoietin (rhEPO) on erythropoiesis when given at different time intervals to healthy adults. 15 volunteers were randomly selected to receive rhEPO (2 x 300 U/kg) and parenteral iron (2 x 200mg) either within a 24 h or 72 h interval. Controls received parenteral iron only. Maximum EPO levels were found 24 h after the first intravenous injection (day 1) with a mean value of 364 and 390 U/l for the rhEPO-treated groups. When second rhEPO administration was after 72 h (group III), volunteers showed significantly higher absolute reticulocyte counts and a higher percentage of young RNA-rich reticulocytes (HFR ratio) over several days compared to those who received rhEPO within a 24 h interval (group II). Both rhEPO-treated groups showed an increase in the mean reticulocyte cell volume. Reticulocyte haemoglobin concentration was inversely correlated with the increasing cell size with a nadir on day 8. Reticulocyte haemoglobin content showed a significant decrease in group II after day 5. Serum ferritin levels showed an inverse pattern to the rate of erythropoiesis. After an initial rise, the serum ferritin decrease was most pronounced in group III. Contrary to previous reports with oral iron supplementation, functional iron deficiency was not seen during rhEPO stimulation, due to parenteral iron administration. Our data suggest that the time has interval between repeated administrations of rhEPO has an important influence on its pharmacodynamics. rhEPO given within an interval of 72 h was more effective in stimulating erythropoiesis than administration within 24 h interval for the same total dose.

Lipid mediators in the rat retina: light exposure and trauma elicit leukotriene B4 release in vitro.

Light exposure not only elicits a visual response but may also alter functional and structural characteristics of the retina. Furthermore, light exposure can lead to reversible or irreversible lesions of photoreceptors and pigment epithelium. Previous studies in our laboratory have shown that light liberates arachidonic acid from retinal membrane phospholipids mainly by activating the phospholipase A2. In this study we show that light and trauma elicit the synthesis of leukotriene B4 in the isolated rat retina in vitro. Male albino rats were dark adapted for 36 h, isolated retinae were taken, incubated and exposed a) either to darkness or to 5,000 lux of cool white fluorescent light for 5, 10 or 15 min at 37 degrees C, b) either to darkness or to 5,000 lux of cool white fluorescent light for 15 min at 0 degrees C or c) either to darkness or to 5,000 lux of cool white fluorescent light for 15 min at 37 degrees C with a 5-lipoxygenase inhibitor (zileuton). Eicosanoids were extracted and leukotriene B4 levels were determined by radioimmunoassay. Removal of retinae and incubation in darkness caused a significant rise in leukotriene B4 levels with increasing incubation time. This rise was further augmented significantly after light exposure. The leukotriene B4 levels obtained when incubating the retinae either at 0 degree C or with the lipoxygenase inhibitor zileuton as well as the high specificity of the radioimmunoassay indicate that the light- and trauma-elicited synthesis of leukotriene B4 is mediated by activating the 5-lipoxygenase. Leukotriene B4 may be involved, at least in part, in the pathogenesis of retinal diseases including light damage. Curr. Eye Res. 14: 1001-1008, 1995.

[Cotinine--a useful biomarker for tobacco use?]. / Cotinin--ein sinnvoller Biomarker für den Tabakkonsum?

Nicotine consumption is one of the most important avoidable risk factors for atherosclerosis and cardiovascular, pulmonary as well as many other diseases. In daily practice one cannot always clearly detect whether a patient remains really abstinent. 68 patients following consultations for risk factors were included in this study. Smoking habits were evaluated by means of a questionnaire and by measurement of carbon monoxide concentration in the breath; also the cotinine concentrations in saliva and urine were investigated during consultation. Cotinine is one of the most important metabolic product of nicotine. Smokers showed significantly increased carbon monoxide concentrations in the breath as well as increased cotinine concentrations in urine and saliva. Anamnestic information from patients about their nicotine consumption correlated well with the cotinine concentration in urine and saliva (r = 0.54). The best correlation was found between creatine-corrected cotinine concentration and cigarette consumption on the day preceding in measurement (p < 0.001, r = 0.66). It is not clear if and to what extent cotinine determination may qualify for the evaluation of passive smoking; however, measurement of cotinine concentrations in saliva (or urine) represents a good biochemical parameter for the control of nicotine abstinence.

[Abnormal increase in pancreatic polypeptide in the secretin-provocation test: hypoglycemia-induced?]. / Abnormer Anstieg des pankreatischen Polypeptids im Sekretin-Provokationstest: hypoglykämiebedingt?

Pancreatic polypeptide (PP) can be used as a marker for endocrine active tumors originating from the pancreas. After intravenous administration of secretin, individually divergent increases in plasma PP concentration can be observed hampering interpretation of the stimulation test. Under certain circumstances elevated basal PP concentrations can be observed. Besides age, renal insufficiency and diabetes, hypoglycemia can cause high PP levels. We therefore inquired whether in patients with atypically high increase of PP after secretin this increase could be caused by hypoglycemia during the secretin stimulation test. In order to test this hypothesis we prospectively determined the plasma glucose and insulin concentrations in addition to the routinely measured gastro-intestinal hormones in 19 patients referred for secretin provocation test. In the 16 patients in whom the increase of PP was not due to an endocrine active tumor or renal insufficiency, PP rose to 170 +/- 57 pmol/l (+/- SEM) 2 minutes after secretin administration. In parallel, plasma insulin concentration increased to 365 +/- 51 pmol/l 2 minutes after secretin. The maximal insulin concentrations correlated significantly with the PP concentrations observed at the same time (R = 0.73, p < 0.01). The mean glucose concentration, however, remained constantly between 4.8 +/- 0.3 and 5.2 +/- 0.3 mmol/l and there was no correlation between the peak plasma PP concentrations after secretin and the plasma glucose concentrations (R = 0.07). The minimal glucose concentrations observed were 3.3 mmol/l in three patients (30 minutes after secretin in 2 patients and 45 minutes after secretin in one). The mean plasma glucagon concentration rose to 22.5 +/- 4.1 pmol/l 10 minutes after secretin.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic value of urokinase plasminogen activator for prostatic carcinoma.

The usefulness of routine clinical application of the urokinase plasminogen activator in prostate cancer was evaluated. The urokinase values of prostate cancer confined to the organ, with extraprostatic spread and with metastatic disease did not differ and showed no significant difference in comparison with benign prostatic hyperplasia. Urokinase is not a useful parameter in clinical routine.

A new look at the limits of detection (LD), quantification (LQ) and power of definition (PD)

The relationship between the concentration of the analyte and the imprecision of an analytical method can be displayed by the precision profile in which the coefficient of variation (relative standard deviation) is plotted against the concentration of the analyte. The function of the curve of the profile and its confidence limits can easily be assessed by a computer program developed by W.A. Sadler & M.H. Smith (Clin. Chem. 36 (1990), 1346-1350). For the assessment of limits of detection and of quantification the following procedure is proposed: The lower (and upper) limit of the measuring interval is defined by the point at which an acceptable CV-line intersects the confidence limit. If, in the variance function one sets the concentration to zero, the normal distribution of the random errors of the blank will result. The mean of the next adjacent normal distribution, following the variance formula and overlapping the "zero-distribution" by a defined amount, represents the limit of detection. Within the described measuring interval, or within a fraction of it, one might construct overlapping normal distributions in an analogous manner. Their number represents the "power of definition" (PD) (instead of the "analytical sensitivity"), which also depends on the concentration of the determinand according to the variance function. We tested these hypotheses by a comparison of two methods for the determination of cyclosporin A (ciclosporin, INN). Our results demonstrate that the data of the lower limits of the measuring interval and of the limit of detection agree well with data from the literature obtained in extensive interlaboratory surveys.

[Prevalence of drugs in meconium]. / Prävalenz von Drogen im Mekonium.

BACKGROUND: The number of newborn infants with symptoms suggesting drug withdrawal is increasing. As only part of prenatally exposed infants show typical drug withdrawal, and drug-use reported by addicted mothers is often unreliable the prevalence of neonates that were exposed to illicit drugs before birth is unknown. The purpose of this study was to evaluate prospectively the prevalence of drugs in meconium and to define risk factors for intrauterine drug exposure. METHODS: During a period of 4 months meconium was collected twice in 420 nonselected newborn infants. Meconium was analysed with a modified test developed for toxicology screening in urine. Information on pre- and postnatal risk factors including drug-use during pregnancy was obtained. RESULTS: Among 415 mothers four reported illicit drug use and ten licit drug use during late pregnancy. In all these infants meconium drug test was positive. After exclusion of these infants and of five second twins 401 infants with negative drug history remained. 45 of them (11%) had one or two drugs in the meconium: opiate 17x, amphetamine 16x, barbiturate 15x, benzodiazepine 3x, cannabinoid 2x, cocaine 1x (in 9 infants two substances were detected). None was positive for LSD or phencyclidine. The infants with positive drug tests had the following risks compared to those with negative tests: prematurity (odds ratio 2.3, 95% confidence interval 1.3-4.3). Microcephaly or macrocephaly (2.0:1.01-4.1), Apgar-Score below 5 at 1 min (2.4:1.5-5.4), Apgar score below 7 at 10 min (4.0: 1.6-9.9), mother academic (2.8:1.2-6.2). CONCLUSIONS: Newborn infants may have been exposed to illicit drugs in utero even if their mothers deny drug use and even if they do not show withdrawal symptoms. Prematurely born infants and infants with problems in postnatal adaptation have an increased risk of having been exposed to drugs.

[Detection of drugs in meconium]. / Nachweis von Drogen im Mekonium.

BACKGROUND: The number of newborn infants exposed to drugs in utero is on the increase in many European countries. As drug use reported by addicted pregnant women is unreliable there is a need for an accurate test to determine the drugs to which an infant has been exposed in utero. The purpose of this study was to evaluate the reliability of toxicology testing in meconium compared with traditional urine testing. METHODS: From twenty newborn infants born to drug-dependent mothers, meconium and urine were collected as soon as possible after birth and tested for drugs with the same radioimmunoassay. Five neonates were premature (Gestational weeks less than 37), six were small and three microcephalic for gestational age. RESULTS: Meconium was positive for drugs in 19 infants (95%) (Methadone 9, Morphine 9, Cocaine 6, Cannabis 4). Urine testing revealed the presence of drugs in 13 babies (65%) (Methadone 9, Morphine 6, Cocaine 4, Cannabis 1, Barbiturates 1). Five infants did not have any drug withdrawal, five had mild and ten severe withdrawal symptoms necessitating treatment with chlorpromazine and in four instances additional pethidine. CONCLUSIONS: Meconium is not only easier to collect but also at least as reliable as urine for drug detection in neonates.

Heparin-coated left heart bypass: renal function and hormonal response.

The effect of partial (50 ml/min/kg) left heart bypass (LHBP) on renal function, plasma renin activity (PRA), aldosterone, arginine vasopressin and atrial natriuretic peptide (ANP) response was studied in ten anesthetized, open-chested mongrel dogs (weight 23-50 kg) over a period of 6 h. Standard equipment with systemic heparinization (control), initially 300 IU/kg, was employed in five dogs, and heparin-coated equipment without additional heparin in the other five (heparin coated). Urine was continuously collected through a transurethral catheter. Urine samples and pulmonary artery blood samples for hormonal assays were taken at preset intervals before and during LHBP. The results in each group were summarized as median (25th-75th) and compared using the Mann-Whitney U test. In the control group higher blood loss required higher volume substitution. Urine output was maintained in heparin coated and slightly decreased at 3-4 h in control LHBP. Creatinine clearance at 3-5 h and free-water clearance at 3-6 h were significantly higher with heparin-coated LHBP. PRA, aldosterone and vasopressin peaked at 1-2 h of LHBP similarly in both groups, not exceeding the values before perfusion. PRA and aldosterone response was sustained during 6 h and the percentage changes corrected for hemodilution indicated a stronger response with standard equipment. Vasopressin concentrations were slightly but significantly higher in the control group at 1 and 6 h of perfusion. Corrected for hemodilution, vasopressin percentage changes were not different in the two groups. ANP, despite atrial unloading, rose similarly in both groups. There was a tendency to poorly sustained ANP response (control greater than heparin-coated) after 6 h of perfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative determination of selenium in the serum of various animal species and humans by means of electrothermal atomic absorption spectrometry.

It was the goal of this paper to establish total selenium reference values for Switzerland in different animal species and in humans. To this purpose, a flameless atomic absorption method with deuterium background compensation utilizing a graphite furnace atomization system with a pyrolytic platform inside and palladium solution as matrix modifier was developed for the measurement of selenium in serum. The method was characterized by rapid performability, small sample requirement, acceptable detection limit (0.04 mumol/L) and precision and a linear range of measurement up to 4 mumol/L. The method proved to be suited for routine application in species with low selenium concentrations, such as cattle. It may be useful wherever small amounts of serum have to be analysed, e.g. in neonatology. Reference values of serum selenium concentration were determined in healthy subjects of various species, including man. They were as follows (min = 5%, max = 95% percentile values in mumol/L): humans (20-60 years): 0.78-1.48, humans (60-100 years): 0.61-1.73, horse: 0.36-1.68, dog: 1.90-4.31, cat: 3.60-10.09, cattle greater than 9 months: 0.10-0.82, calves 3-9 months: 0.19-0.65, sheep: 0.09-0.54, goat: 0.14-1.42, chicken: 1.68-4.28 and pig: 1.97-3.32. From the data it was concluded (i) that the serum selenium concentration depended on the amount of selenium in the food, and on the type of digestive tract; (ii) that carnivors had the highest and ruminants the lowest selenium values; and (iii) that up to 20% of the geriatric donors had inadequate selenium levels.

Failure to find a relationship between mnestic skills of octogenarians and aluminum in drinking water.

High concentrations of aluminum (greater than 80 micrograms/l) in drinking water have been related to an elevated incidence of Alzheimer's disease. Mnestic and naming skills of residents living for greater than 15 years in districts with high (98 micrograms/l) or low (4 micrograms/l) aluminum concentrations [Al] in the drinking water were evaluated in a population survey by examining 800 residents aged 81 to 85 using the mnestic subtest of the Mini Mental Status test (Zurich variant). The mnestic and naming performance of the octogenarians did not differ between the high- and low-content-areas. Since 73% of dementias are at least partly caused by Alzheimer's disease in the area examined and because the short test used discriminates demented from healthy octagenarians as well as tests involving extensive examinations, the findings of this study suggest with a high probability that the [Al] of drinking water is not an essential factor in the pathogenesis of senile dementia. The serum [Al] the urinary [Al] and the urinary [Al]/creatinine ratio were measured twice in ten clinically diagnosed Alzheimer patients and ten controls in both areas. No significant difference was found, which confirms the negative epidemiological findings.

Intercostal nerve block for minor breast surgery.

Two anesthetic procedures, intercostal nerve block (ICNB) and general anesthesia, were evaluated in 45 female patients scheduled for minor breast surgery. The study was designed to compare ICNB with general anesthesia for breast surgery with respect to efficacy, surgical stress and postoperative analgesia and to evaluate epinephrine and ornipressin as vasoconstrictors in the local anesthetic solution. Thirty patients received ICNB of T3-T7 unilaterally using 2% lidocaine plus epinephrine (15 patients, Group A) and 2% lidocaine plus ornipressin (15 patients, Group B). The control group consisted of 15 patients receiving a general anesthetic. The highest median lidocaine plasma level was 2.8 micrograms/ml in those patients who received epinephrine and 5.3 micrograms/ml in those who received ornipressin. There were statistically significantly higher lidocaine plasma levels in Group B than in Group A after 10, 30 and 60 minutes from injection while the two groups did not differ significantly at the 20- and 90-minute time intervals. Before and during surgery, epinephrine and norepinephrine plasma levels were highest in the epinephrine group, whereas, postoperatively, the plasma levels of both catecholamines were highest in the patients receiving general anesthesia. The latter patients experienced significantly more nausea and vomiting than the regional anesthesia groups. Patients with regional anesthesia required significantly less analgesics postoperatively than the patients receiving general anesthesia.