Biomedical subjects

S Hahn

Publications and source records attributed to S Hahn.

At least 37 records · Page 2Linked to original sources

PubMed2005

Effects of estrogen replacement therapy on bone and glucose metabolism in a male with congenital aromatase deficiency.

Little is known about the impact of estrogen replacement therapy for bone formation, glucose metabolism and hormonal parameters on males with aromatase deficiency. Transdermal estrogen (TE) replacement was initiated at 100 microg/week in months 0-3, 50 microg/week in months 3-6, 25 microg/week in months 6-12, 75 microg/week in months 12-24, and 25 microg/week in months 24-36 to substitute for the deficiency in a 27-year-old homozygous male with a mutation on the CYP19 gene. Estradiol levels increased from<10 at baseline to 45, 12, 27 and 17 pg/ml (normal range 10-50) after 6, 12, 24 and 36 months, and inversely correlated to LH and FSH levels. Testosterone levels changed from 31.2 nmol/l at baseline to 3.8, 22.1, 7.1 and 22.0 nmol/l (9.5-30) after 6, 12, 24 and 36 months, respectively, and correlated closely to basal and stimulated LH and FSH levels at 100 microg GnRH. Bone maturation progressed, and metacarpal and phalangeal epiphysis closed after 12 months. Spongiosa-hydroxyapatite of the radius assessed by quantitative computed tomography changed from 52 to 83, 51, 69 and 71 mg/cm3 (120-160); bone mineral density of the lumbar spine assessed by dual energy X-ray-absorptiometry (normal value>1.150) increased from 0.971 (T-Score -2.24) to 1.043 (-1.64), 1.065 (-1.46), 1.128 (-0.93) g/cm2 and 1.021 (-1.82) after 6, 12, 24 and 36 months of TE, respectively. Osteocalcin as a bone formation parameter and aminoterminal collagen type I telopeptide as a bone resorption parameter increased during high-dose estrogen supplementation, and then decreased during the lower doses. Lipoprotein (a) increased from 20 mg/dl at baseline to 60 and 62 mg/dl after 6 and 12 months, and then decreased to 24 and 25 mg/dl after 24 and 36 months, respectively, while total cholesterol, HDL, LDL and triglycerides did not change. AUC glucose decreased continuously after oral glucose load, and HOMA IR reached its lowest value the 75 microg weekly estradiol dose. This study confirms the role of estrogens in achieving bone mineralization and maturation in human males. Additionally, estradiol has dual negative feedback sites that on the hypothalamus to decrease GnRH pulse frequency, and on the pituitary to decrease responsiveness to GnRH. The improvement in glucose metabolism after estrogen replacement therapy suggests a probable role of sex steroids in insulin sensitivity. The optimal weekly dose of transdermal estrogen replacement for normalizing estrogen levels and maintain bone mass in adult males with aromatase deficiency may be 50-75 microg spread over two doses.

Adult↗

PubMed2005

Clinical and biochemical characterization of women with polycystic ovary syndrome in North Rhine-Westphalia.

Polycystic ovary syndrome (PCOS), defined as the combination of oligoanovulation and hyperandrogenism, affects more than 5% of women of reproductive age. Insulin resistance and hyperinsulinemia appear to play an important role in its pathogenesis. Here, we will present a characterization of a PCOS cohort from North Rhine-Westphalia in Germany. Clinical features, family history as well as endocrine and metabolic parameters were prospectively recorded from 200 successive patients. All patients were evaluated for insulin resistance and beta-cell-function by oral glucose tolerance test. Patient data were compared with those of 98 age-matched control women. PCOS patients showed significantly higher BMI, body fat mass and androgen levels as well as impaired glucose and insulin metabolism. A positive family history of PCOS and diabetes was more frequent in PCOS patients. Insulin resistance (71%) was the most common metabolic abnormality in PCOS patients followed by obesity (52%) and dyslipidemia (46.3%), with an incidence of 31.5% for the metabolic syndrome. C-reactive protein and other cardiovascular risk factors were frequently elevated even in young PCOS patients. While the clinical characteristics and endocrine parameters of this German PCOS cohort were heterogeneous, they were comparable to those from other Caucasian populations.

Adult↗

PubMed2005

Binding, stimulating and blocking TSH receptor antibodies to the thyrotropin receptor as predictors of relapse of Graves' disease after withdrawal of antithyroid treatment.

TSH-receptor autoantibodies (TRAbs) are a valuable diagnostic tool for confirming a diagnosis of Graves' disease (GD). While there is evidence that high TRAb levels are associated with relapse of GD, whether a discrimination of TRAb into stimulating (TSAb) and blocking (TBAb) autoantibodies would benefit the clinician in terms of outcome prediction remains unclear. To address this issue, we have determined TRAb, TSAb and TBAb levels in serum samples of ninety-six euthyroid patients with GD taken four weeks after antithyroid drug withdrawal (ATDT). Forty-seven patients (49 %) underwent relapse of GD within two years. Amongst those, forty-one (87 %) had been positive for TRAb and thirty-five (74 %) for TSAb after treatment. All patients except one were negative for TBAb. The correlation between TRAb and TSAb in those treated GD patients was relatively weak (r = 0.268, p < 0.001). Based on a cut-off limit of 1.5 IU/l, the positive and negative predictive values with respect to prediction of relapse were too low for any clinical relevance (TRAb: 49 % and 54 %; TSAb: 51 % and 55 %). However, when a cut-off level above 10 IU/l was used, the positive and negative predictive values increased to 83 % and 62 %. The additional measurement of TSAb or TBAb in those samples after therapy did not add additional information, even at higher decision thresholds. In conclusion, differentiation of TRAb into TSAb and TBAb is of no help in the prediction of relapse of GD in euthyroid patients at the end of ATDT, and only high TRAb levels are associated with relapse.

Adolescent↗

PubMed2005

Constant IFNgamma mRNA to protein ratios in cord and adult blood T cells suggests regulation of IFNgamma expression in cord blood T cells occurs at the transcriptional level.

Low levels of IFNgamma produced by umbilical cord blood (UCB) T lymphocytes upon activation may be due to the need for a high threshold of activation or to intrinsic blocking transcription/translation. We examined IFNgamma mRNA accumulation and protein expression in pharmacologically stimulated human UCB and adult blood (AB) T cells. Our data indicate that both IFNgamma mRNA accumulation and protein synthesis were significantly lower in stimulated UCB T cells than the AB T cells. Since the RNA dependent kinase PKR, an inhibitor of translation, can be activated by low levels of IFNgamma mRNA, we measured its involvement. Treatment with 2-amino-purine, an inhibitor of PKR, did not enhance IFNgamma protein expression in UCB T cells. Furthermore, our studies indicated that IFNgamma promoter hypermethylation does not appear to regulate IFNgamma expression either, as treatment with the demethylating agent, 5-aza-2'-deoxycytidine, did not lead to a significant increase in IFNgamma mRNA accumulation in UCB T cells. What is readily evident from our studies is that the IFNgamma mRNA to protein ratio was similar in UCB and AB T cells and it was not altered by any of the treatments used. These results therefore suggests that IFNgamma expression in UCB T cells is suppressed at the transcriptional level by an unknown mechanism(s).

2-Aminopurine↗

PubMed2005

Accuracy of fetal echocardiography in the routine detection of congenital heart disease among unselected and low risk populations: a systematic review.

OBJECTIVE: To determine among unselected and low risk populations the accuracy with which fetal echocardiography during the second trimester detects congenital heart disease. DESIGN: A systematic review of studies that assess the accuracy of fetal echocardiography. SETTING: District General Hospital and Tertiary referral centres. POPULATION: Women during the second trimester attending for ultrasound assessment. METHODS: General bibliographic databases (e.g. MEDLINE, EMBASE) and specialist computerised databases (e.g. Cochrane Library, National Research Register), grey literature, manual searching of reference lists of primary and review articles and personal contact with experts were used to identify studies. Studies were included if fetal echocardiography among unselected or low risk pregnant women was compared against a postnatal reference standard. Data were extracted on quality, study design and characteristics, and accuracy data to construct 2 x 2 tables. Data were synthesised qualitatively, and sensitivity and specificity with 95% confidence intervals were calculated. MAIN OUTCOME MEASURE: Sensitivity and specificity. RESULTS: Five primary studies met the inclusion criteria and comprised 60,901 subjects. One study assessed the accuracy of fetal echocardiography among an unselected population and four studies among low risk populations. All eligible studies found that fetal echocardiography helped to correctly diagnose normal fetus among unselected and low risk populations. Correct diagnosis of babies for congenital heart defects was higher among the unselected population (85%) than among the low risk populations (range from 35% to 86%); however, the potential for ascertainment bias and the choice of reference standard limits the validity of this finding. The variation in sensitivity across studies was not explainable by clinical factors such as scanning regime, operator skill and equipment. CONCLUSIONS: The evidence from this review about the accuracy of fetal echocardiography does not lend support to its routine use among unselected and low risk populations during the second trimester to detect congenital heart disease.

Echocardiography↗

PubMed2005

The costs and effects of introducing selectively trained radiographers to an A&E reporting service: a retrospective controlled before and after study.

The costs and effects of introducing selectively trained radiographers reporting accident and emergency (A&E) radiographs of the appendicular skeleton in a district general hospital were assessed using a retrospective controlled before and after design. Reference standard reports were compared with a random stratified sample of 200 A&E and 200 general practitioner (GP) reports before and after the intervention. GP reports were used as a non-intervention, non-equivalent control group. An A&E specialist registrar judged whether incorrect A&E reports might have a clinically important effect on patient management. The effect of incorrect A&E reports on outcome was assessed by patient re-attendance to the hospital because of missed abnormalities. The annual, average and incremental costs of radiographers and radiologists reporting A&E radiographs were calculated and a sensitivity analysis was undertaken. The introduction of the radiographers resulted in a 1% (95% CI -7.9 to 5.9) fall in A&E radiograph reporting accuracy and 11% (95% CI -33.7 to 11.3) reduction of cases in which incorrect A&E reports might have a clinically important effect on patient management. Only two A&E reports (one before and one after the intervention) affected patient outcome in that a fracture missed at the first visit resulted in patient re-attendance to the X-ray Department. There was a saving of 361 pounds per annum to the X-ray Department. In conclusion this study provides further evidence that selectively trained radiographers can accurately report A&E plain radiographs and at no additional cost.

Clinical Competence↗

PubMed2005

Insulin resistance syndrome and polycystic ovary syndrome: implications for diagnosis and treatment.

Both insulin resistance syndrome (IRS) and polycystic ovary syndrome (PCOS) are common endocrinopathies. IRS, usually associated with ages of 50+, type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD), is highly prevalent in young PCOS patients, exceeding the expected rate from their prevailing obesity. While it is clear that women with PCOS cluster risk factors, prospective studies to prove a higher morbidity and mortality from T2DM and CVD are not available. Nevertheless, apart from cosmetic concerns and gynecological problems, therapeutic intervention should also be designed to reduce the metabolic risk of PCOS, which may well be the main determinant of long-term health in affected women.

Animals↗

PubMed2004

Fetal cells and cell free fetal nucleic acids in maternal blood: new tools to study abnormal placentation?

The analysis of fetal cells, and more recently cell free fetal nucleic acids, in maternal blood has to date largely been concerned with the development of risk free methods for prenatal diagnosis. Although elevated feto-maternal cell trafficking has long been associated with preeclampsia, it has only recently been shown that this perturbation is an early event in these pregnancies, occurring well in advance of the onset of symptoms. In a separate development, analogous observations have been made concerning the levels of circulatory fetal nucleic acids in maternal plasma. Subsequent studies have shown that changes in these two parameters may also occur in other pregnancy related disorders including preterm labour, intra-uterine growth retardation, hyperemesis gravidarum or even pregnancies at high altitude. A striking finding of these examinations was that preterm labour was associated with an elevated release of cell free fetal nucleic acids but not with an increment in feto-maternal cell trafficking. This suggested that the analysis of the mechanisms regulating trans-placental cell trafficking or liberation of circulatory fetal nucleic acids may provide key insights into the fundamentally different placental lesions underlying these disorders. As such, circulatory fetal cells and nucleic acids may be viewed as new tools to study alterations in placentation.

Adult↗

PubMed2004

Reduced osmolarity oral rehydration solution for treating cholera.

BACKGROUND: Oral rehydration solution (ORS) is used to treat dehydration caused by diarrheal diseases including cholera. Reduced osmolarity formulations are safe and more effective than standard ORS for treating non-cholera diarrhea. As cholera causes rapid electrolyte loss, it is important to know if these benefits are similar for people with cholera. OBJECTIVES: To compare the safety and efficacy of reduced osmolarity oral rehydration solution (ORS) with standard ORS for treating diarrhea due to cholera. SEARCH STRATEGY: We searched the Cochrane Infectious Disease Group Specialized Register (January 2004), CENTRAL (The Cochrane Library Issue 1, 2004), MEDLINE (1966 to January 2004), EMBASE (1974 to January 2004), and LILACS (1982 to January 2004). We also contacted organizations and searched reference lists. SELECTION CRITERIA: Randomized controlled trials comparing reduced osmolarity ORS with standard ORS for treating adults and children with acute diarrhea due to cholera. DATA COLLECTION AND ANALYSIS: Two reviewers independently applied eligibility criteria, assessed trial quality, and extracted data. We pooled binary data using relative risks (RR), continuous data using weighted mean difference (WMD) or the standardized mean difference (SMD), and presented the results with 95% confidence intervals (CI). MAIN RESULTS: For glucose-based reduced osmolarity ORS, seven trials (718 participants) met the inclusion criteria. Biochemical hyponatremia (serum sodium < 130 mmol/L) was more common with reduced osmolarity ORS (RR 1.67, CI 1.09 to 2.57; 465 participants, 4 trials); for severe biochemical hyponatremia (serum sodium < 125 mmol/L) this was not significant (RR 1.58, CI 0.62 to 4.04; 465 participants, 4 trials). No trials reported symptomatic hyponatremia or death. We found no statistically significant difference in the need for unscheduled intravenous infusion. Analyses separating children and adults showed no obvious trends. Two trials also examined rice-based ORS. In the reduced osmolarity group, duration of diarrhea was shorter (WMD -16.85 hours, CI -21.22 to -12.48; 102 participants, 2 trials). REVIEWERS' CONCLUSIONS: In people with cholera, reduced osmolarity ORS is associated with biochemical hyponatremia when compared with standard ORS, although there are similar benefits in terms of other outcomes. Although this risk does not appear to be accompanied by serious consequences, the total patient experience in existing trials is small. Under wider practice conditions, especially where patient monitoring is difficult, caution is warranted.

Adult↗

PubMed2004

[Metformin, an efficacious drug in the treatment of polycystic ovary syndrome].

BACKGROUND AND OBJECTIVE: Polycystic ovary syndrome (PCOS), with an incidence of 5% in women of reproductive age, is defined as the presence of oligo- or amenorrhea in combination with hyperandrogenism. Most patients also suffer from impaired insulin action (insulin resistance). PCOS thus resembles the metabolic syndrome (type 2 diabetes mellitus, hypertension, lipid disorders, atherosclerosis). International studies showed a beneficial effect of metformin treatment on biochemical and reproductive parameters in PCOS. The aim of our study is the evaluation of metformin treatment in a German PCOS sample. PATIENTS AND METHODS: 103 PCOS women (age 18-40) were treated, according to their body weight, with either 1000 mg or 1700 mg metformin per day after assessment of insulin resistance. Clinical features as well as endocrine and metabolic parameters were recorded at baseline and at 1, 6, and 12 months of treatment. Additionally, baseline data were compared with those of 98 control subjects (age 18-38). RESULTS: PCOS women showed significantly higher body mass index, body fat mass and androgen levels, as well as an impaired glucose- and insulin metabolism compared to controls. Metformin treatment ameliorated acne (36% to 4%), hirsutism-score (11.2 to 9.7) and restarted normal menstrual cycles in 66.7% of PCOS-women. Sixteen of 48 patients with unfulfilled wish to conceive became pregnant during therapy. Metformin restored menses in all previously amenorrheic women. Comparing post-metformin versus baseline levels, HOMA-IR (4.6 to 2.3), AUC-I (379 to 225) and 2-h glucose (117 to 90 mg/dl) decreased significantly. Furthermore, metformin decreased testosterone (2.9 to 1.8 nmol/l), free androgen index (9.1 to 5.3) and dehydroepiandrosterone levels (5.1 to 3.9 mg/l). CONCLUSION: Metformin improves significantly hyperandrogenism and insulin resistance in PCOS patients and appears to be an efficacious mode of therapy.

Adolescent↗

PubMed2004

Improved prenatal detection of a fetal point mutation for achondroplasia by the use of size-fractionated circulatory DNA in maternal plasma--case report.

INTRODUCTION: The efficacious analysis of fetal loci involving point mutations from circulatory fetal DNA in maternal plasma is hindered by the preponderance of maternal DNA. It has recently been shown that the size difference between fetal and maternal DNA species can be used for the selective enrichment of circulatory fetal DNA in maternal plasma. We have now tested this approach for the detection of a fetal point mutation in the fibroblast growth factor receptor 3 (FGFR3) gene that causes achondroplasia. METHODS: Circulatory DNA was extracted from maternal plasma and size-fractionated by agarose gel electrophoresis. The fraction with a size less than 300 bp was examined by a touchdown PCR assay specific for the FGFR3 gene, and the mutation was identified by SfcI restriction analysis. RESULT: Our analysis indicated that although the fetal mutation was discernible in the analysis of total plasma DNA, the result using size-fractionated DNA was much more evident. CONCLUSION: The enrichment of circulatory fetal DNA in maternal plasma by size-fractionation facilitates the detection of subtle feto-maternal genetic differences, such as those involving point mutations. This approach can easily be extended for the non-invasive prenatal determination of other fetal loci.

Achondroplasia↗

PubMed2004

Acute toxicity investigations of ester-based lubricants by using biotests with algae and bacteria.

Although ester-based lubricants are ecologically acceptable due to their good biodegradability, there are still some environmental ecotoxicological impacts that have to be considered. Information on the acute ecotoxicological behavior of lubricants is obtained in this work using several single species bioassays. In previous studies it was observed that lubricating fluids containing additives for the enhancement of their technical performance were more problematic than base fluids especially with respect to algae growth inhibition. In order to clarify the influence of additives, the anti-wear additive tri-n-butyl phosphate was tested. It was very toxic to algae though not to bacteria. Additionally, a mixture of this additive with a base fluid is characterized. Despite the high toxicity of the single additive, the water extract of the mixture of tri-n-butyl phosphate with hydraulic base fluid caused almost no toxicity. Therefore, tri-n-butyl phosphate cannot explain the effect observed for the toxicity of water extracts of the commercially available lubricants.

Biological Assay↗

PubMed2004

Phase I trial of UFT/leucovorin and irinotecan in patients with advanced cancer.

UFT (BMS-200604, Uftoral) is an oral fluoropyrimidine that combines uracil and the 5-fluorouracil (5-FU) prodrug, ftorafur, in a 4:1 molar ratio with single-agent activity in breast and gastrointestinal cancers. In vitro studies have shown that irinotecan downregulates thymidylate synthase (TS) expression in tumour cells, leading to synergy between irinotecan and 5-FU that is maximal when irinotecan is given 24 h prior to 5-FU. Given this observed synergy and the confirmatory clinical activity of combination therapy with 5-FU, leucovorin (LV) and irinotecan, we performed a phase I trial to determine the maximum tolerated doses (MTD) of UFT, LV, and irinotecan. Treatment consisted of irinotecan administered as a 90-min intravenous (i.v.) infusion on day 1 followed by twice daily oral UFT/LV on days 2-15, repeated every 21 days. Initial doses were irinotecan 200 mg/m(2) and UFT 200 mg/m(2)/day, with LV dose fixed at 60 mg/day. 31 patients received a total of 130 cycles of UFT/LV and irinotecan. 3 of 9 patients experienced grade 3/4 diarrhoea at the highest dose level of irinotecan 310 mg/m(2) and UFT 300 mg/m(2)/day. Other toxicities included neutropenia, anaemia, alopecia, nausea/vomiting and fatigue. Further dose escalation was not pursued since this level of toxicity was appropriate for future phase II study. One patient with colorectal cancer experienced a partial response and 9 patients with non-small cell lung, colorectal and gastro-oesophageal junction carcinomas had disease stabilisation lasting 4-26 (median 6) cycles. Methylenetetrahydrofolate reductase (MTHFR) C677T genotype was analysed in peripheral mononuclear cells (PMNs) obtained from 24 patients. 2 patients had the homozygous TT polymorphism and 1 of them had grade 3 diarrhoea at the first dose level. Irinotecan on day 1 followed by a 14-day course of oral UFT/LV beginning on day 2 is well tolerated, and suitable for testing in several tumour types. Doses recommended for further study on this schedule are irinotecan 310 mg/m(2) and UFT 300 mg/m(2)/day, with LV 60 mg/day.

Administration, Oral↗

PubMed2004

The effect of the elapsed time between blood draw and processing on the recovery of fetal cells from maternal blood.

OBJECTIVE: To test the hypothesis that a delay in initial fetal cell enrichment processing of maternal blood samples (defined as the time between blood draw and the initial density gradient centrifugation step) compromises the ability to recover fetal cells, we performed a randomized comparison of immediate (within 4 hours of draw) versus delayed (between 18-24 hours of draw) processing. METHODS: Four centers participated: two centers utilized flow cytometry (FLOW), and two centers utilized magnetic-activated cell sorting (MACS) techniques. Each center collected 34 samples. The outcome was the percentage of gamma positive (gamma(+)) cells for FLOW or the number of nucleated red blood cells (NRBCs) for MACS, found in the final enriched cell population. Both outcomes reflect cell properties that are potentially fetal in origin, thus making them representative of the ability to recover fetal cells. RESULTS: Our results did not support our hypothesis that delay in processing compromises fetal cell recovery. Instead, in MACS processing, we observed an increase in recovered NRBCs when blood sample processing was delayed compared with immediate processing. There was no significant difference in gamma(+) cells with FLOW. CONCLUSION: Time-related changes in the density of target cells, perhaps associated with their progress towards apoptosis during the delay period, may result in increased intact fetal cells with the study methods utilized.

Apoptosis↗

PubMed2004

Clinical biochemical genetics in the twenty-first century.

Genetic disorders are recognized to play an increasing role in pediatrics. Close to 10% of diseases among hospitalized children have been ascribed to Mendelian traits inherited as single gene defects, not a surprising figure considering that approximately 1000 inborn errors of metabolism (IEM) have been identified to date, primarily through the detection of endogenous metabolites abnormally accumulated in biological fluids and tissues. The laboratory discipline that covers the biochemical diagnosis of IEM is known as clinical biochemical genetics, and is defined as one concerned with the evaluation and diagnosis of patients and families with inherited metabolic disease, monitoring of treatment, and distinguishing heterozygous carriers from non-carriers by metabolite and enzymic analysis of physiological fluids and tissues. The biochemical genetics laboratory differs from the clinical chemistry laboratory in the extent of interpretation necessary to make its results meaningful to the clinician. While dramatic advances in molecular genetics have greatly changed the landscape of diagnostic options for many genetic disorders, a biochemical approach remains the dominant force for the diagnosis and monitoring of IEM. Owing to the stereotypical clinical presentation of many of these disorders, a major role of the biochemical genetics laboratory is to analyze ever more complex metabolic profiles to reach a preliminary diagnosis, which then needs to be confirmed by enzymic and/or molecular studies in vitro. Accordingly, the role of biochemical genetics in the pediatric practice of the 21st century is to provide a multicomponent screening process that can be divided into four major components: (i) at-risk screening (prenatal diagnosis); (ii) newborn screening (testing of presymptomatic patients); (iii) high-risk screening (testing of symptomatic patients); and (iv) postmortem screening (metabolic autopsy). The focus of our laboratory is to apply state-of-the-art technology such as tandem mass spectrometry to bring as many as possible IEM within the boundaries of newborn screening programs, and to investigate the role played by individual disorders in maternal complications of pregnancy, pediatric acute/fulminant liver failure, and sudden and unexpected death in early life.

Autopsy↗

PubMed2004

The Munich Barrett follow up study: suspicion of Barrett's oesophagus based on either endoscopy or histology only--what is the clinical significance?

BACKGROUND: The incidence of distal oesophageal adenocarcinoma is rising, with chronic reflux and Barrett's oesophagus being considered risk factors. Reliable detection of Barrett's oesophagus during upper endoscopy is therefore mandatory but requires both endoscopy and histology for confirmation. Appropriate management of patients with endoscopic suspicion but negative on histology, or vice versa, or of patients with no endoscopic suspicion but with a biopsy diagnosis of intestinal metaplasia at the gastro-oesophageal junction, has not yet been studied prospectively. PATIENTS AND METHODS: In a prospective multicentre study, 929 patients (51% male, mean age 50 years) referred for upper gastrointestinal endoscopy were included; 59% had reflux symptoms. The endoscopic aspect of the Z line and any suspicion of Barrett's oesophagus were noted, and biopsies were taken in all patients from the Z line (n = 4), gastric cardia (n = 2), and body and antrum (n = 2 each). Biopsies positive for specialised intestinal metaplasia (SIM) were reviewed by a reference pathologist for a final Barrett's oesophagus diagnosis. All patients with endoscopic and/or histological suspicion of Barrett's oesophagus were invited for a follow up endoscopy; the remaining cases (no endoscopic or histological suspicion of Barrett's oesophagus) were followed clinically. RESULTS: Of 235 patients positive for Barrett's oesophagus on endoscopy and/or histology, 63% agreed to undergo repeat endoscopy (mean follow up period 30.5 months). 46% of patients with an endoscopic Barrett's oesophagus diagnosis but no histological confirmation (group A) showed the same distribution, a further 42% did not have Barrett's oesophagus, and 11% had confirmed Barrett's oesophagus on both endoscopy and biopsy on follow up. In the group with a histological Barrett's oesophagus diagnosis but negative on initial endoscopy (group B), follow up showed the same in 26% whereas 46% had no Barrett's oesophagus, and confirmed Barrett's oesophagus (endoscopy plus histology) was diagnosed in 17%. Of the study population, 16 patients had Barrett's oesophagus on initial endoscopy confirmed by histology which remained constant in 70% at follow up (group C). Of the remaining patients without an initial Barrett's oesophagus diagnosis on either endoscopy or histology (group D) and only clinical follow up (mean follow up period 38 months), one confirmed Barrett's oesophagus case was found among 100 patients re-endoscoped outside of the study protocol. However, no single case of dysplasia or cancer of the distal oesophagus was detected in any patient during the study period. CONCLUSIONS: Even in a specialised gastroenterology setting, reproducibility of presumptive endoscopic or histological diagnoses of Barrett's oesophagus at follow up were poor. Only 10-20% of cases with either endoscopic or histological suspicion of Barrett's oesophagus had established Barrett's oesophagus after 2.5 years of follow up. The risk of dysplasia in this population was very low and hence meticulous follow up may not be required.

Adolescent↗

PubMed2004

Development of automated high-throughput ecotoxicity and genotoxicity test systems and fields of application.

Bioassays like growth inhibition and genotoxicity assays are frequently used for the characterization of chemicals and contaminated environmental samples. In this work two standardized bioassays are automated completely using newly developed liquid handling stations and robotics. A high-throughput algal growth inhibition assay prototype is set up and optimized in cooperation with Hoelle & Huettner AG (Tuebingen, Germany) and Polygen GmbH (Langen, Germany). A software package for both the control of the test system and for data evaluation has been developed (Biolane Supervisor, BioLane Manager HTT). The applicability of the prototype is demonstrated by testing reference compounds with the automated assay in parallel with the Erlenmeyer flask assay. It is shown that EC50-values of chemicals do not differ significantly when incubation parameters like homogeneity of light intensity, temperature and evaporation during 72 hours of incubation are optimized. The umu-genotoxicity test is automated completely using a "RoboSeq 4204 SE" pipetting station (MWG AG, Ebersberg, Germany) equipped with two shakers, microplate photometer, four pipettes, stacker for ten microplates and incubation cabin with temperature regulation. As a result of miniaturization and automation large numbers of toxicants and far more treatments and parallels can be tested and, additionally, only low sample volumes are needed.

Automation↗

PubMed2003

Determination of RHD zygosity using real-time quantitative PCR.

At present RHD incompatibility is still an obstetric problem despite prophylactic treatment. A very welcome recent technical advance has now made it possible to determine the foetal RHD status in a non-invasive risk-free manner using cell free foetal DNA in maternal plasma. In some cases, however, where there is a high risk that the foetus may be affected by HDN (haemolytic disease of the newborn), it may be of interest to determine whether the father is hetero- or homozygous for the RHD gene, since in the former instance there is only a 50% chance that the pregnancy is affected. It has recently been shown that quantitative PCR assays, in particular real-time Taqman PCR, can be used to determine the RHD gene dosage, and also to determine foetal aneuploidies. We demonstrate that the same real-time Taqman PCR assay we had previously developed for non-invasive analysis of the foetal RHD gene and the foetal Y chromosome from maternal plasma can be used to determine the paternal RHD genotype.

DNA↗