Biomedical subjects

S Armbrust

Publications and source records attributed to S Armbrust.

5 recordsLinked to original sources

PubMed2005

Smith-Lemli-Opitz syndrome with a classical phenotype, oesophageal achalasia and borderline plasma sterol concentrations.

The diagnostic biochemical hallmarks of Smith-Lemli-Opitz syndrome (SLOS) are elevated concentrations of the cholesterol precursors 7- and 8-dehydrocholesterol (7- and 8-DHC). We describe a patient with classical SLOS phenotype and oesophageal achalasia, which has not been reported in SLOS patients before. Plasma 7-DHC and 8-DHC were only marginally elevated. The diagnosis was confirmed by sterol analysis in cultured skin fibroblasts and mutation analysis.

Cell Culture Techniques↗

PubMed2005

Superovulation and embryo recovery from peripubertal Holstein heifers.

The use of peripubertal donors in embryo transfer (ET) programs presents significant opportunity to accelerate genetic gain in domestic livestock by reducing the generation interval. These studies were designed to evaluate feasibility of superovulation and embryo recovery in peripubertal heifers (starting at 7.8 months of age), and to determine whether subsequent reproductive and lactational performance of donor heifers were impaired. Study 1 utilized 10 pairs of contemporary full-sibling heifers in which one heifer in each pair was assigned to receive a superovulation regimen and her full-sibling contemporary received placebo. Treated heifers were artificially inseminated at estrus and embryos were flushed transcervically 4-6 days later. Based on recovery of oocytes and/or embryos, 9 of 10 heifers responded to the hormonal regimen and 12 total embryos were recovered. Seven embryos (58%) were transferred into recipients resulting in five pregnancies. Control and treated heifers remained in the herd and were bred at a natural estrus by AI at 15 months of age. Lactation records, i.e., 305 days mature equivalent (305 d ME) were obtained, and all animals were evaluated for udder conformation traits between 32 and 38 months of age. Reproductive traits (age at first calving and days to conception) and lactational traits of heifers subjected to embryo transfer and their non-treated full-siblings did not differ (P > 0.05). Study 2 was conducted to establish the commercial feasibility of hormonally programming peripubertal heifers ranging in age from 7.8 to 9.9; 10 to 11.9; 12 to 13.9 and >/= 14 months. In total, 3982 embryos were recovered from 520 heifers, with 2419 (60.7%) of those categorized as viable (transferable). The number of ova/embryos obtained per flush (5.6 +/- 1.0) and the number of transferable embryos (2.8 +/- 0.5) was reduced (P < 0.05) in heifers of age 7.8-9.9 months compared to all other age groups. There was no difference (P > 0.05) in the number of ova/embryos recovered (7.8 +/- 0.3), or the number of transferable embryos (4.8 +/- 0.2), among heifers that were >/=10 months of age. The number of unfertilized ova did not differ by age, however, more degenerate embryos tended to be recovered from heifers <10 months of age compared to heifers >/=14 months of age. These data indicate that transferable embryos can be safely recovered from heifers beginning at 10 months of age without compromising subsequent reproductive or lactational performance of the donor.

Aging↗

PubMed2004

Resting energy expenditure in obese children aged 4 to 15 years: measured versus predicted data.

AIM: To measure the relationship of resting energy expenditure (REE) and body composition, and to compare REE data calculated from anthropometric parameters using published equations with measurements obtained by indirect calorimetry (IC) in a population of obese paediatric patients. METHODS: The study included 82 healthy obese paediatric subjects (49 boys, 33 girls; body mass index 29.6 +/- 5.0 kg/m , age 1 1.4 +/- 2.6 y, weight 72.4 +/- 20.9 kg, height 155 +/- 14 cm). REE was measured by IC, body composition was determined by dual energy X-ray absorptiometry (DXA). Bootstrap analysis was performed to validate the step-down linear regression analysis results. RESULTS: Lean body mass (LBM) and weight were identified as the most significant determinants of REE. LBM was the best single predictor (r = 0.78; p < 0.001) for REE. Regression equations are given in the text. Prediction of REE on the basis of published anthropometric formulas was strongly dependent from the equation used. Some equations tend to underestimate REE in the population studied with a considerable systematic error. CONCLUSION: In the present paper we show that (1) the published equations to predict REE in obese subjects yield scattered data and some are even biased by a systematic error, and that (2) the inclusion of DXA-derived LBM improves accuracy and precision of predicted REE in boys and girls aged from 4 to 10 y and in boys from 11 to 15 y.

Absorptiometry, Photon↗

PubMed1998

Linearity and accuracy errors in bone densitometry.

This investigation was undertaken to quantify accuracy errors and identify possible linearity errors in dual energy X-ray absorptiometry (DXA) of bone, based on studies of commercially available bone densitometers for planar densitometry. The following was found in a combination of in vitro phantom studies and in vivo investigations of human volunteers: (1) Pronounced differences between the instruments when measuring vertebral size and contours of the projected bone regions. (2) Falsely low bone mineral content (BMC in terms of g) in cases of low nominal bone mass, due to the fact that edge regions were omitted by the calculation software of some devices. (3) An increase in the projected bone area secondary to an increase in nominal bone mass with some instruments. (4) Clinically and statistically significant errors of accuracy of BMC and to a lesser extent bone mineral density (BMD). (5) Substantial linearity errors with some osteodensitometers for BMC, a phenomenon that reduces the usefulness of this parameter. It is concluded that DXA devices are affected by a combination of accuracy errors and linearity errors, some more than others, and that linearity errors influence their ability to monitor change in BMC and to a lesser extent in BMD, making system intercomparison difficult.

Adult↗

PubMed1995

Recent developments in DXA. Quality of new DXA/MXA-devices for densitometry and morphometry.

The introduction of new devices demands the assessment of their capabilities in established terms. The accuracy, reproducibility and spatial resolution of in vitro (phantom) osteodensitometric and morphometric measurements of QDR 2000 Plus and EXPERT are presented. Design details of these DXA/MXA-devices are listed and discussed in combination with the data acquired in the test measurements and calculations. The image quality will improve with further software developments. The long-term reproducibility and in vivo reliability remains to be evaluated.

Absorptiometry, Photon↗