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Biomedical subjects

Andreas R Huber

Publications and source records attributed to Andreas R Huber.

30 records · Page 2Linked to original sources
PubMed2004

Glucagon-like peptide 1 induces natriuresis in healthy subjects and in insulin-resistant obese men.

Glucagon-like peptide-1-(7-36)-amide (GLP-1) is involved in satiety control and glucose homeostasis. Animal studies suggest a physiological role for GLP-1 in water and salt homeostasis. This study's aim was to define the effects of GLP-1 on water and sodium excretion in both healthy and obese men. Fifteen healthy subjects and 16 obese men (mean body mass index, 36 kg/m2) were examined in a double-blind, placebo-controlled, crossover study to demonstrate the effects of a 3-h infusion of GLP-1 on urinary sodium excretion, urinary output, and the glomerular filtration rate after an i.v. 9.9-g salt load. Infusion of GLP-1 evoked a dose-dependent increase in urinary sodium excretion in healthy subjects (from 74 +/- 8 to 143 +/- 18 mmol/180 min, P = 0.0013). In obese men, there was a significant increase in urinary sodium excretion (from 59 to 96 mmol/180 min, P = 0.015), a decrease in urinary H+ secretion (from 1.1 to 0.3 pmol/180 min, P = 0.013), and a 6% decrease in the glomerular filtration rate (from 151 +/- 8 to 142 +/- 8 ml/min, P = 0.022). Intravenous infusions of GLP-1 enhance sodium excretion, reduce H+ secretion, and reduce glomerular hyperfiltration in obese men. These findings suggest an action at the proximal renal tubule and a potential renoprotective effect.

Adult↗
PubMed2003

Telehematology: critical determinants for successful implementation.

Despite modern technologies, such as immunophenotyping and molecular probing, cytomorphologic examination of stained peripheral blood smears by microscopy remains the mainstay of diagnosis in a large variety of diseases. This holds true especially in underdeveloped or rural areas where profound expertise and equipment are not easily available. Although communication technologies have been dramatically improved, telehematology has not become routine. To date, little information is available on which procedures are critical for successful implementation. Therefore, a study evaluating possible factors that prevented implementation of telehematology was initiated. We found that staining technique, smearing procedure, training skills, number of captured images, and prevalent disease influenced the accuracy of diagnosis by the reference laboratory. Using realtime teleconferencing allowed for overcoming these deficits. Together, when certain rules are observed, telehematology allows for rapid, accurate, standardized, and cheap expert advice. This technology should improve treatment of patients in remote areas where expertise is not available.

Hematology↗
PubMed2003

A differentiated approach to assess the diagnostic usefulness of a rapid particle gel immunoassay for the detection of antibodies against heparin-platelet factor 4 in cardiac surgery patients.

Enzyme-linked immunosorbent assay (ELISA) methods have shown to be of a low specificity for confirming heparin-induced thrombocytopenia (HIT) in cardiac surgery patients. In other patient collectives, a new antigen test [ID-HPF4 Particle Gel Immuno Assay (PaGIA); Diamed, Cressier sur Morat, Switzerland] was recently reported to exhibit a better specificity than the ELISA. Since a more specific test would serve as a useful tool when diagnosing HIT, a prospective study was carried out to elucidate the specificity and diagnostic usefulness of PaGIA in cardiac surgical patients. As assessed in cardiac surgery patients without HIT, the proportion of PaGIA-positive samples was lowest at baseline (16%; 13/74), increasing to 31% (19/61) at postoperative days 5-9 (P = 0.06) and 69% (29/42) at postoperative days 10-18 (P < 0.001 versus postoperative days 5-9). The respective proportions in an ELISA (HPF4 ELISA; Stago, Asnières sur Seine, France) were lower. Because the prevalence of antibody positivity increases during the postoperative course, a differentiated mathematical model was used to assess predictive values and likelihood ratios (LR) of the PaGIA at three different phases of hospitalization. Calculating LR revealed -LR to be 0.07 at baseline, 0.09 during postoperative days 5-9, and 0.19 during postoperative days 10-18, while +LR were 5.9 at baseline, 3.0 during postoperative days 5-9, and 1.4 during postoperative days 10-18. Thus, in cardiac surgery patients, the PaGIA can be regarded as a useful tool in excluding rapid onset and typical onset of HIT, and further provides valuable information in the confirmation of rapid onset of HIT. Using a differentiated approach for calculation of predictive values and LR, the present study demonstrates that PaGIA, despite a lower specificity than the employed ELISA, in some situations is a valuable tool when diagnosing HIT in cardiac surgery patients.

Aged↗
PubMed2003

Association of anti-heparin platelet factor 4 antibody levels and thrombosis in pediatric intensive care patients without thrombocytopenia.

Anti-heparin platelet factor 4 (anti-HPF4) antibodies have been demonstrated to play a pathogenetic role in the development of heparin-induced thrombocytopenia. In adults, the presence of anti-HPF4 antibodies without thrombocytopenia has been reported not to confer a thrombotic risk. To investigate whether this also holds true for children, we performed a case-control study in heparin-exposed patients from a pediatric intensive care unit. During the 30-month study period, 612 patients received heparin for at least 5 days. Of these, 10 patients developed thrombosis without thrombocytopenia and constituted the study group. These patients were compared with 19 matched control patients with neither thrombosis nor thrombocytopenia. Anti-HPF4 antibody levels were measured using an enzyme-linked immunosorbent assay (Asserachrom HPF4). All thrombosis patients and controls had lower anti-HPF4 antibody levels than the cut-off level recommended by the manufacturer for adults. However, median anti-HPF4 antibody levels were significantly higher in the thrombosis patients [51% of the manufacturer's cut-off; interquartile range (IQR), 47-53%] than in the control group (23%; IQR, 9-36%) (P = 0.004). At an anti-HPF4 cut-off level of 45%, the odds ratio for a thrombotic event amounted to 34 (95% confidence interval, 4.4-261.8), indicating an association between anti-HPF4 antibody levels and thrombosis despite the absence of thrombocytopenia. A role of anti-HPF4 antibodies in the development of catheter-related thrombosis is suggested.

Autoantibodies↗
PubMed2003

Quantitative urine particle analysis: integrative approach for the optimal combination of automation with UF-100 and microscopic review with KOVA cell chamber.

BACKGROUND: Automated systems have enabled the counting of particles in urine to be standardized. Their superiority over traditional sediment analysis has been well documented, but they have not gained wide acceptance. The reasons for this are that sediment analysis has been performed and interpreted for decades. Additionally, pathologic casts and other unknown particles still must be confirmed under the microscope. Furthermore, comparison between the methods has revealed outliers and thus decreased confidence in automation. METHODS: We used the standardized KOVA cell chamber system to count particles and compared the results with UF-100 flow cytometry as an alternative to traditional sediment analysis. RESULTS: We compared 252 randomly selected urine samples and obtained a review rate of 33%. Microscopic verification was necessary because of the presence of casts, yeast, sperm, dysmorphic erythrocytes, and some misclassified erythrocytes or leukocytes that were detected by incongruent dipstick results and abnormal scattergrams. We obtained correlation coefficients of 0.966 for erythrocytes and 0.935 for leukocytes. Criteria for an algorithm to identify samples that needed microscopic review were derived from comparisons between the number of particles from UF-100, dipstick results, cell chamber counting, and sediment analysis. CONCLUSIONS: Automated cell counting combined with microscopic counting with a standardized cell chamber system is useful. An objective algorithm for review criteria can be developed via systematic comparison of UF-100 flow cytometry and microscopy. Only urine samples that meet these criteria need to be confirmed microscopically.

Algorithms↗
PubMed2002

Mural thrombus of the aorta in association with homozygous plasminogen activator inhibitor type 1 (PAI-1)-675(4G) and heterozygous GP Ia 807C/T genotypes.

Thrombus formation in the thoracic and abdominal aorta without evidence of arteriosclerotic disease is very uncommon. We present a case of a 50-year-old woman with a mural thrombus of the upper abdominal aorta associated with a combination of two mutations predisposing for thrombophilia. The genetic analysis showed a homozygous mutation of plasminogen activator inhibitor type 1 (PAI-1)-675 (4G) and a heterozygous mutation of GP Ia 807C/T. To our knowledge, this is the first report of the combination of both mutations occurring in a patient with isolated thrombus formation of the aorta.

Aorta, Abdominal↗
PubMed2002

Estimating phosphate removal in haemodialysis: an additional tool to quantify dialysis dose.

BACKGROUND: Half of the dialysis population suffers from hyperphosphataemia, which is now recognized as a major factor of haemodialysis (HD) morbidity and mortality. Current control is focussed on reducing dietary phosphate intake and diminishing absorption using phosphate binders, whereas control and quantification of phosphate removal by HD is undervalued. The aim of this prospective study was to develop a simple, bedside formula to estimate dialytic phosphate removal in stable HD patients. METHODS: This was a prospective, randomized trial. Phosphate and urea elimination were assessed in a representative group of patients at two dialysis centres using randomly different dialysers (1.3-2.4 m(2)). Quantification was performed by partial dialysate collection, concentration measurements in blood and effluent dialysate spot samples, and Kt/V(urea) during standard high-flux HD. Multiple linear regression analyses were used in 77% of all data sets to generate an equation to predict phosphate removal. The formula was validated in the remaining 23% of data sets, in the same group of patients using a large capillary filter, and in diabetic patients treated with a small dialyser at different blood flows (200, 250, and 300 ml/min). RESULTS: A formula allowing quantification of phosphate removal within one HD session was developed in 18 of 74 patients during 41 treatments (137 out of 177 data sets) and was determined as: M(PO4pred)=0.1t -17+50c(ds60)+11c(b60), where t is treatment time in min, c(ds60) and c(b60) are phosphate concentrations in dialysate and plasma measured 60 min into HD in mmol/l, and M(PO4pred) is estimated phosphate removed in mmol. The precision was remarkable (r(2)=0.92-0.94). The comparison of phosphate and Kt/V(urea) showed a significant association (r(2)=0.28), albeit with remarkable scatter. CONCLUSIONS: We present the first approach to quantify phosphate removal during high-flux HD by a bedside formula. Only 28% of the variation in phosphate removal was explained by Kt/V(urea). It appears that other factors not adequately accounted for by Kt/V(urea) affect phosphate removal. Therefore, we propose an individual control and quantification of phosphate removal in HD.

Aged↗
PubMed2002

Heparin-induced thrombocytopenia-associated thrombosis in pediatric intensive care patients.

BACKGROUND: Heparin-induced thrombocytopenia (HIT), a well-known side effect of heparin therapy, occurs in 1% to 5% of adults exposed to heparin. Of those, about 29% to 88% develop thrombosis. Most data on HIT-associated thrombosis in children are confined to anecdotal reports. OBJECTIVE: To determine the incidence of HIT-associated thrombosis in heparin-exposed children. METHODS: We performed a retrospective cohort study on all patients admitted to our pediatric intensive care unit between August 1996 and January 1999. Patients who received heparin for >/=5 days were eligible. Within these patients, we identified all cases of radiologically confirmed thrombosis. Cases of thrombosis were reviewed for fulfillment of clinical HIT criteria. HIT-associated thrombosis was confirmed serologically by determination of levels of antibodies against heparin/platelet factor 4 complexes. RESULTS: Of 1950 children admitted during the study period, 612 were exposed to heparin for >/=5 days. Thrombosis occurred in 57 patients (9.3%). Plasma samples were available for 38 cases, of which 14 satisfied clinical HIT-criteria. Calculated incidence rate for HIT-associated thrombosis: 2.3%, (95% confidence interval: 1.3%-3.9%, for patients exposed to heparin >/=5 days). Nine patients suffered from venous, 2 patients from arterial, and 3 had combined arterial and venous thrombosis. None of the 14 patients died or underwent amputation. Six patients had heparin and platelet factor 4-complex antibody levels above the cutoff level for adults. The remaining 8 patients had significantly higher antibody levels than a matched control group. CONCLUSION: Compared with that reported for adults, HIT-associated thrombosis in pediatric intensive care unit patients has a similar incidence but a less severe outcome.

Adolescent↗