PubMed Health⌕ Search

Biomedical subjects

V Seifert-Klauss

Publications and source records attributed to V Seifert-Klauss.

10 recordsLinked to original sources
PubMed2006

The 3D-based scaling index algorithm: a new structure measure to analyze trabecular bone architecture in high-resolution MR images in vivo.

INTRODUCTION: The purpose of this study was to obtain different structure measures as the three-dimensional (3D)-based scaling index method (SIM) and standard two-dimensional (2D) bone histomorphometric parameters from high-resolution (HR) magnetic resonance (MR) images of the distal radius and to compare these parameters with bone mineral density (BMD) in their diagnostic performance to differentiate postmenopausal patients with and without vertebral fractures. METHODS: Axial HR-MR images of the distal radius were obtained at 1.5 T in 40 postmenopausal women (17 with osteoporotic spine fractures and 23 controls). Trabecular microarchitecture analysis was performed using the new structure measure mP(alpha), derived from the SIM, as well as standard morphological 2D parameters. BMD of the spine was obtained using quantitative computed tomography (QCT). Receiver operating characteristic (ROC) analyses were used to determine diagnostic performance in differentiating both groups. Results were validated by bootstrapping techniques. RESULTS: Significant differences between both patient groups were obtained using mP(alpha), 2D parameters, and spine BMD (p<0.05). In comparison with the 2D texture parameters [area under the curve (AUC) up to 0.67], diagnostic performance was significantly higher for mP(alpha)(AUC=0.85; p<0.05). There was a trend for a higher AUC value for mP(alpha) compared with BMD of the spine (AUC=0.71; p=0.81). CONCLUSION: mP(alpha) yielded a robust measure of trabecular bone microarchitecture for HR-MR images of the radius, which significantly improved the diagnostic performance in differentiating postmenopausal women with and without osteoporotic spine fractures compared with standard 2D bone histomorphometric parameters. This 3D characterization of trabecular microarchitecture may provide a new approach to better assess the strength of human cancellous bone using HR-MR image data.

Aged↗
PubMed2006

Influence of pattern of menopausal transition on the amount of trabecular bone loss. Results from a 6-year prospective longitudinal study.

INTRODUCTION: Bone density is lower in postmenopausal than in premenopausal women. Recent findings have suggested that accelerated bone loss already begins before menopause. Despite numerous cross-sectional studies on menopause-related bone density, longitudinal data on perimenopausal bone density changes are scarce. This study sought to characterize the dynamics of changes leading to postmenopausal osteopenia and to possibly find the time point at which accelerated bone loss begins. METHODS: We prospectively followed 34 pre-, peri- and early postmenopausal women without prior external hormone use, measuring their lumbar spine trabecular bone density with quantitative computer tomography at 0, 2 and 6 years. The analysis of the changes over time was done in a tri-parted fashion, since menopausal status changed variably for individual subjects: we grouped the participants according to their currently valid menopausal classification for prospective (baseline classification), interim (2 years) and retrospective (6-year classification) analysis. RESULTS: Six different patterns of menopausal transition were identified in our sample. Bone loss in the groups not reaching postmenopause during 6 years of observation was >50% of the maximum bone loss observed during the study period. Invariably for all analyses, the perimenopausal phase with estrogen levels still adequate was associated with the greatest reduction of trabecular bone mineral density, reaching 6.3% loss annually in the lumbar spine. By comparison, the average rate of loss was slower in the early postmenopause; total bone loss differed by pattern of menopausal transition (one-way ANOVA p<0.05). CONCLUSION: The presented data for the first time show the perimenopausal course of trabecular bone loss (as measured by QCT of the lumbar spine). Acceleration of bone loss during perimenopause reached half-maximal values of the total bone loss measured around menopause, despite adequate serum estradiol levels.

Bone Density↗
PubMed2005

[Bone metabolism, bone density and estrogen levels in perimenopause: a prospective 2-year-study].

Bone metabolism and trabecular bone density were studied prospectively in 69 pre-, peri- and early postmenopausal women. Markers of bone resorption (OC = osteocalcin, BAP = bonespecific alkalic phosphatase) and bone formation (PYD = pyridinolin, DPD = desoxypyridnolin, NTX = N-terminal telopeptide crosslinked collagen type I, CTX = C-terminal telopeptide crosslinked collagen type I) in serum and urine were followed over a course of two years with five points of examination (0, 3, 6, 12 and 24 months). Bone density was measured at 0 and 24 months. The results of 40 hormonally untreated women who completed all examinations were compared regarding menopausal status and changes over the 2-year-period. While baseline tracecular bone density was lowest in early postmenoapusal women, perimenopausal women showed greatest bone loss (- 10,6 %) during the two year study period. Bone metabolism markers were highest in the postmenopausal group. Perimenopause was associated with a gradual rise in OC, PYD and CTX. Perimenopausal women showed the highest serum estradiol at 0 and 12 months with values exceeding those of premenopausal women. Whether the increased perimenopausal bone loss could be related to the increase in anovulatory cycles during the perimenopausal transition is subject to ongoing investigation.

Adult↗
PubMed2003

[Hormone therapy in menopause. A current update].

While the use of hormone replacement therapy (HRT) for prophylactic indications such as cardiovascular disease, osteoporosis, and Alzheimer's disease was increasingly propagated during the 1990s, recent studies have reported no risk reduction for women after myocardial infarction (HERS) or women from a mixed population with an average age of 63 years (Women's Health Initiative [WHI] Study). The results of the latter study even suggest an increased risk for cardiovascular events and breast cancer with previous or ongoing combined oral estrogen plus progestin. A final risk-benefit assessment for estrogen monotherapy will only be possible after the ongoing part of the WHI Study has been evaluated, expected in 2005. As effects, side effects, and contraindications for HRT in postmenopausal women are better known, the need for individualized risk assessment and the definition of therapeutic goals increases. Since the WHI Study did not address the risk-benefit ratio for women with perimenopausal complaints or osteoporosis or with lower dose hormone preparations commonly used in Germany, there is an urgent need to answer these open questions with large confirmative studies.

Aged↗
PubMed2001

Myocardial blood flow and flow reserve in response to short-term cyclical hormone replacement therapy in postmenopausal women.

OBJECTIVES: To measure the effects of combined cyclical hormone replacement therapy (HRT) on myocardial blood flow (MBF) in postmenopausal women at high risk for coronary heart disease (CHD) and in women with documented CHD. BACKGROUND: Estrogen restores endothelium-dependent vasodilation in response to acetylcholine in postmenopausal women, and it has a direct, endothelium-independent vasodilatory effect on coronary arteries. METHODS: To determine whether coronary microcirculation can be affected by short-term, combined HRT, we performed positron emission tomography (PET) in two groups of women without previous HRT. Group I (n = 10) had one or more risk factors for CHD; group II (n = 8) had documented CHD and previous myocardial infarction. Group II was older (54 +/- 4 vs 59 +/- 5 y, P = .03) and had lower total cholesterol levels at baseline because of lipid-lowering therapy (244 +/- 31 vs 203 +/- 40 mg/dL, P = .03). Patients underwent baseline dynamic PET with N-13 ammonia at rest and during maximal adenosine-induced hyperemia to assess MBF. Each then began taking HRT (conjugated equine estrogen alone or with medroxyprogesterone acetate (MPA), administered in cyclical fashion), and returned for follow-up PET 46 +/- 12 days later. RESULTS: There was no difference in resting MBF between groups I and II prior to starting therapy or at follow-up. Stress MBF and flow reserve (FR) tended to be higher in group I patients at baseline. MBF values remained unchanged at follow-up and resulted in similar FR values at baseline and during HRT for both groups. Women using only estrogen (n = 6) tended to show higher FR values after estrogen therapy, however. CONCLUSIONS: Short-term HRT in postmenopausal women did not lead to improvements in MBF or FR. Combined cyclical HRT may not exert measurable effects on coronary microcirculation. MPA may attenuate estrogen effects on the coronaries, which may be largely endothelium-dependent.

Adenosine↗
PubMed2000

[Contraception in patients with congenital heart defects].

The number of women with congenital cardiac disease, who mature into adulthood is increasing. Unfortunately, there are no prospective data published about the relative risk of different forms of contraception for these patients. Most women with congenital cardiac disease can safely use oral contraceptives, especially low-estrogen combination or progestin-only preparations, with the exception of those, who are at particular risk because of thromboembolic complications (especially in cyanosis, pulmonary hypertension, Eisenmenger reaction, rhythm disturbances), fluid retention (especially in reduced ventricular function and congestive heart failure), arterial hypertension (important in coarctation), infectious complications (endocarditis) or hyperlipidemia. Oral contraceptives should be avoided in patients at increased risk for thromboembolic events. Intrauterine devices are very effective, have no metabolic side effects and merely carry a small risk of endocarditis. Newer devices containing progesterone only may put the patients at a still smaller risk. Contraceptive subdermal implants (e.g. levonorgestrel) are used with good results in the United States for patients with contraindications to estrogen-containing oral contraceptives and may well become more widely accepted in patients in Germany in the coming years. Barrier methods can be used, but have a higher failure rate, which may be unacceptable in patients at risk (e.g. Eisenmenger's). Especially in Eisenmenger's, permanent sterilisation should be advised.

Adolescent↗
PubMed1999

Gender differences in myocardial blood flow dynamics: lipid profile and hemodynamic effects.

OBJECTIVES: The purpose of the study was to compare myocardial blood flow (MBF) in hyperlipidemic postmenopausal women and age-matched hyperlipidemic men, and to analyze the relationship between cholesterol subfractions and myocardial blood flow in men and women. BACKGROUND: Women are protected from coronary artery disease (CAD) events until well after menopause, in part due to gender-specific differences in lipid profiles. METHODS: To examine the effect of these influences on coronary microcirculation, MBF was quantitated with N-13 ammonia/PET (positron emission tomography) at rest and during adenosine hyperemia in 15 women and 15 men, all nondiabetic, who were matched for age and total cholesterol levels (53+/-4 vs. 50+/-8 years, p = NS, 6.44+/-1.1 vs. 6.31+/-0.85 mmol/liter, or 249+/-41 vs. 244+/-33 mg/dl, p = NS). RESULTS: Women had significantly higher high density lipoprotein (HDL) and lower triglyceride (Tg) levels than did men, and they showed significantly higher resting MBF and stress MBF levels. Significant correlations were found between resting and hyperemic MBF and HDL and Tg levels (r = 0.44, p < 0.02 for stress MBF vs. HDL; r = 0.48, p < 0.007 for stress MBF vs. Tg). Gender was the strongest predictor of hyperemic MBF in multivariate analysis. Women responded to adenosine hyperemia with a significantly higher heart rate than did men, and hemodynamic factors correlated significantly with blood flow both at rest and during stress. CONCLUSIONS: These data suggest that the favorable lipid profile seen in women may be associated with preserved maximal blood flow in the myocardium.

Adenosine↗
PubMed1995

[Idiopathic subfertility: pregnancy rate after IVF treatment in minimally stimulated monofollicular ovarian cycle].

Fifty-nine patients with idiopathic subfertility were treated with IVF in 176 minimally stimulated cycles. Twenty pregnancies were achieved, resulting in pregnancy rates of 11.4% per treatment cycle and 21.3% per embryo transfer. Thus, the mode of treatment described here appears to be an useful alternative to IVF or laparoscopic GIFT in gonadotropin-stimulated cycles, since it carries good chances of success while avoiding the risk of massive ovarian hyperstimulation and increased incidence of multiple pregnancies.

Adult↗
PubMed1994

A three step protocol for the treatment of idiopathic subfertility.

650 couples with idiopathic subfertility (mean duration: 5.7 year, range 2-21 years) were treated during 2870 cycles by three assisted conception methods (each involving mild ovarian stimulation): I timed intercourse (TI), II intrauterine insemination (IUI). III in vitro fertilization/embryo transfer (IVF/ET). Treatment started with TI in most cases and then changed to IUI after three to six cycles. Couples who failed to conceive were treated after another 3-9 cycles by IVF/ET. An overall cumulative pregnancy rate of 80.2% was reached after 18 treatment months. The pregnancy rates per treatment cycle were: TI 5.3%, IUI 6.9%, IVF/ET 15.8% (per oocyte retrieval).

Clinical Protocols↗