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Biomedical subjects

J Huber

Publications and source records attributed to J Huber.

At least 91 records · Page 5Linked to original sources
PubMed1998

Sudden unexpected death in infancy: epidemiologically determined risk factors related to pathological classification.

Infants that died suddenly and unexpectedly were studied as part of the European Concerted Action on sudden infant death syndrome (SIDS). Three paediatric pathologists, first independently of each other and later in a consensus meeting, classified 63 cases into 3 groups: SIDS (19 cases), borderline SIDS (30 cases) and non-SIDS (14 cases). The interobserver agreement among the pathologists before the consensus meeting was moderate (Kappa = 0.41) and jointly it was higher (Kappa = 0.83). The distribution of epidemiologically determined risk factors was studied over these three groups. Maternal smoking after birth, low socioeconomic status and thumb sucking were found more often in SIDS than in the other cases. Inexperienced prone sleeping was a determinant for SIDS, but not for non-SIDS. Previous hospital admission, low birthweight and/or short gestation were associated with borderline SIDS. Non-SIDS cases received more breastfeeding, the parents hardly smoked during pregnancy and after birth, a firm mattress had been used, and more often signs of illness had been reported by the parents, compared with the SIDS and borderline SIDS cases. Bedding factors and both primary and secondary prone sleeping were equally distributed over the three groups which supports the hypothesis that, in SIDS and borderline SIDS, as well as in non-SIDS cases, some similar external and preventable factors might influence the events leading to death. Research should therefore focus on all sudden unexpected deaths, after which subgroups such as SIDS cases can be separately analysed. The postmortem is an essential part of the whole work-up of each case and the results should be interpreted with all other available data to arrive at a sound evaluation of cases and thus form the basis for the prevention of all sudden unexpected infant death.

Bedding and Linens↗
PubMed1998

Case-control study of current validity of previously described risk factors for SIDS in The Netherlands.

This study aimed to assess whether previously established risk factors for sudden infant death syndrome (SIDS) are still valid now that the incidence in the Netherlands has dropped to 0.26 per 1000 liveborn infants. A distinction was made between immutable and mutable risk factors. This case-control study (part of the European Concerted Action on SIDS) comprised 73 SIDS cases and 146 controls and lasted from March 1995 to September 1996. Adjustments were made for sleeping position and bedding factors by treating them as covariables. Apart from these factors, well known risk factors that remain of importance in the Netherlands are: male sex, young maternal age, twins, and low socioeconomic status. These factors are largely immutable. Other well known risk factors which might reflect attitudes to child care and could possibly be mutable are: smoking, alcohol consumption by the mother, bottle feeding, and change of babycare routine. Intervention strategies should focus on early signalling, thereby assisting parents in changing these unfavourable parenting attitudes. Information on optimal child care and extra support by public health nurses specifically aimed at families at risk could help to decrease further the incidence of SIDS in the Netherlands.

Age Distribution↗
PubMed1998

Body composition characteristics after menopause.

The effect of menstrual and reproductive history on body fat development after postmenopause was investigated in 278 healthy females aged between 44 and 67 years (x = 55.8 yrs). The absolute and relative amount of body fat was determined by means of dual energy x-ray absorptiometry. Significant associations between body fat after menopause and age at menarche, age at menopause, and average cycle length were observed. Furthermore the age at first as well as at last birth and the weight gain during pregnancies were related significantly with body fat after menopause. Overweight (BMI > 25.0) during postmenopause was significantly associated with an early menarche, a late menopause, an early first birth and a higher weight gain during pregnancies.

Absorptiometry, Photon↗
PubMed1997

Anti-idiotype RNA selected with an anti-nuclear export signal antibody is actively transported in oocytes and inhibits Rev- and cap-dependent RNA export.

The anti-idiotype approach is based on the assumption that an antibody specific for a receptor-binding domain of a ligand could be structurally related to the receptor. Therefore, a structural mimic of a receptor-binding domain, selected with an anti-ligand antibody, might be a functional substrate for the receptor. This hypothesis was addressed here by generating antibodies recognizing the Rev-nuclear export signal (NES). A functional NES is required for active export, presumably by interacting directly or indirectly with the nuclear pore complex. Anti-NES antibodies were used to isolate RNA mimics of the NES peptide from combinatorial RNA libraries. The RNA-mimics are exported actively, block Rev-dependent export of a reporter RNA, and inhibit cap-dependent U1 snRNA export in Xenopus oocytes, properties previously reported for NES-peptide conjugates.

Animals↗
PubMed1997

Mex67p, a novel factor for nuclear mRNA export, binds to both poly(A)+ RNA and nuclear pores.

An essential cellular factor for nuclear mRNA export called Mex67p which has homologous proteins in human and Caenorhabditis elegans was identified through its genetic interaction with nucleoporin Nup85p. In the thermosensitive mex67-5 mutant, poly(A)+ RNA accumulates in intranuclear foci shortly after shift to the restrictive temperature, but NLS-mediated nuclear protein import is not inhibited. In vivo, Mex67p tagged with green fluorescent protein (GFP) is found at the nuclear pores, but mutant mex67-5-GFP accumulates in the cytoplasm. Upon purification of poly(A)+ RNA derived from of UV-irradiated yeast cells, Mex67p, but not nucleoporins Nup85p and Nup57p, was crosslinked to mRNA. In a two-hybrid screen, a putative RNA-binding protein with RNP consensus motifs was found to interact with the Mex67p carboxy-terminal domain. Thus, Mex67p is likely to participate directly in the export of mRNA from the nucleus to the cytoplasm.

Amino Acid Sequence↗
PubMed1997

[Comparative tribological studies of Chirulen, Hylamer and Enduron combined with A1203].

The creep and wear behaviour of Chirulen, Hylamer and Enduron, materials which differ only in their manufacturing procedures, was examined and compared. Chirulen is manufactured by being pressed into form by plates, whereas Hylamer and Enduron are shaped by tubes. Hylamer differs from Enduron in that intermediate material processing is undertaken with the goal of improving the initial material. The wear and deformation rate was determined by means of the ring-on-disc testing device after 360,000 cycles and after 1.0 x 10(6) cycles, respectively. The static tests for the determination of wear were carried out at a contact stress of 5.62 MPa and a testing time of 100 h in analogy to the ring-on-disc tests. Chirulen and Hylamer demonstrated comparable wear with a tendency toward a lower wear rate in Hylamer, while Enduron presented a clearly higher wear rate.

Biocompatible Materials↗
PubMed1997

[Experimental studies of metal-metal slide combinations and their value in relation to expected in-vivo behavior].

A simulator test was carried out in the hip joint simulator on a metal-on-metal coupling of a modified CoCrMo alloy. The test was run up to 1.9 million cycles and the tribological behaviour of the coupling was documented by means of roundness measurements and scanning electron microscopy. It is seen that the tribological system metal on metal is characterized by mixed friction in the artificial hip joint, thus generating material contacts that are documented by the roundness variation and by the SEM contact zone analysis, showing "three-body" wear of this system. The roundness variations indicate that running-in wear is to be noticed at first with a decreasing tendency over the 1.9 million cycles. Nevertheless, this observation does not allow any prognosis as to the wear rates in the case of a higher number of cycles. It must be taken into consideration that aqua destillata had to be used as a lubricant for technical reasons; the use of serum/Ringer solution might have produced different results. Further investigations in the hip joint simulator and on revised metal-on-metal couplings will be carried out in this respect.

Biomechanical Phenomena↗
PubMed1997

Corticosteroid receptor function is decreased in depressed patients.

Decreased feedback control of the hypothalamic-pituitary-adrenocortical (HPA) system as revealed by the combined dexamethasone and corticotropin-releasing hormone (DEX-CRH) test has been documented in the vast majority of patients with affective disorders. This finding was interpreted as a failure at the level of the glucocorticoid receptor (GR)-mediated feedback action, which apparently fails to restrain HPA activity in the presence of elevated plasma corticosteroid levels. To test this hypothesis we conducted the DEX/CRH test using increasing doses of DEX in order to establish a dose-response relationship. We used three different DEX doses (0.75, 1.5, 3.0 mg) in three groups of depressed patients and controls. As expected, increasing DEX doses were associated with decreasing amounts of adrenocorticotropin (ACTH) and cortisol being released after CRH injection. However, dose-response curves for both plasma ACTH and cortisol concentrations were shifted to higher area under the curve (AUC) values among patients compared to controls. Pretreatment with 0.75 and 1.5 mg DEX produced significantly higher AUC values for both plasma ACTH and cortisol values among patients. These differences became less obvious with the higher DEX doses, indicating that the dose of 1.5 mg used in the majority of clinical studies so far is well suited to differentiate between healthy controls and patients. The reported data here are consistent with the hypothesis that an altered GR capacity or function underlies the exaggerated HPA activity in depression.

Adrenocorticotropic Hormone↗
PubMed1996

Measurement of amniochorionic membrane thickness using high-frequency ultrasound.

Premature rupture of the membranes (PROM) accounts for approximately 30 per cent of all preterm deliveries. PROM is thought to be mainly due to a decrease in membrane integrity. The aim of our investigation was to determine, post-partum after 28 normal deliveries, the thickness of the amniochorionic membrane using a 20 MHz high-frequency ultrasound. The data obtained were compared with histological sections for measurement accuracy using a linear regression analysis method. The membrane thickness of the total study group was 0.83 +/- 0.11 mm (0.72-1.08 mm). Based on a statistical comparison with the histological sections, the high-frequency ultrasound examination was shown to be highly reliable, with a correlation coefficient of r = 0.96 (P < 0.0001). High-frequency ultrasonographic examinations of membrane thickness are an objective and reliable method and may be a gain to prenatal diagnostics once this method can be used in vivo.

Adolescent↗
PubMed1996

Effects of hormonal replacement therapy on plasma sex hormone-binding globulin, androgen and insulin-like growth factor-1 levels in postmenopausal women.

Plasma sex hormone-binding globulin (SHBG) levels are important in the regulation of plasma free and albumin-bound androgens and estrogens. In postmenopausal women associated to the decrease of estrogen production, a decrease of plasma SHBG levels occurs. Hormone replacement therapy (HRT) in postmenopausal women modulates plasma SHBG levels, in relationship with the different regimens and routes of administration. The present study aimed to compare the effect of different HRT on plasma SHBG levels in relationship with the changes of plasma androgen [dehydroepiandrosterone sulphate (DHEAS), testosterone (T), androstenedione (A)] and insulin-like growth factor-1 (IGF-1) levels. In a retrospective study 443 postmenopausal women were studied and divided into 2 groups. The group 1 (n = 170) was subdivided in 4 groups of women as follows: A) treated with transdermal 17-beta estradiol + medroxyprogesterone acetate, B) treated with oral conjugated estrogens, C) treated with sequential HRT (estradiol valerate (EV) + norgestrel), and D) treated with a combined HRT (micronized estradiol (E2) + noretisterone acetate). Women of group 2 (n = 273) did not receive HRT and served as controls. All groups of women treated with different HRT showed plasma estradiol levels significantly higher than controls (p < 0.01), showing the highest values in women treated with oral HRT. Plasma SHBG levels were not significantly different between patients treated with transdermal 17-beta estradiol + medroxyprogesterone acetate and controls. On the other hand, all the groups of patients treated with oral conjugated estrogen with or without progestagens showed plasma SHBG levels significantly higher than controls (p < 0.01). Plasma SHBG levels were higher in the group treated with estrogen alone than in groups of women treated with sequential or combined HRT. Plasma DHEAS, T and A levels in patients treated with different HRT regimens were in the same range of levels as control women. Plasma IGF-1 levels were not significantly affected by the various HRT regimens and remained in the same range as controls. In conclusion, plasma SHBG levels increase following oral HRT while are not affected by transdermal HRT. Plasma IGF-1 and androgen levels are not influenced from oral or transdermal HRT.

Adult↗
PubMed1996

MRI of microadenomas in patients with hyperprolactinaemia.

MRI is a sensitive tool for the investigation of pituitary microadenomas but cannot be used as a screening investigation. To establish a strategy for the use of MRI in patients with hyperprolactinaemia we investigated 74 women with serum prolactin levels above 52 ng/ml for the presence of microadenomas. We examined 55 premenopausal and 19 postmenopausal women, using a 1.5 T unit. We used T1-weighted spin-echo sequences, with coronal and sagittal images before and after intravenous gadolinium. We found microadenomas in 38 patients (51.3%), macroadenomas in 6 (8.1%) and an infundibular glioma in 1;29 patients had a normal pituitary gland (39.2%). The size of the adenomas was related to the prolactin level, and the mean level in patients with MRI evidence of adenomas was higher than in patients without microadenomas (155.72 +/- 131.01 ng/ml versus 110.14 +/- 80.86 ng/ml). The probability of the presence of an adenoma increased with rising serum prolactin levels. We suggest MRI in patients with prolactin levels more than 100 ng/ml. In patients on oestrogen therapy MRI should be performed with only slightly elevated prolactin levels. Evidence of a microadenoma should be considered in planning further therapy, especially concerning the use of hormone replacement therapy or of bromocriptine.

Adenoma↗
PubMed1996

Hormonal, syndromal and EEG mapping studies in menopausal syndrome patients with and without depression as compared with controls.

UNLABELLED: The aim of the study was to investigate brain function in menopausal depression by EEG mapping, as compared with menopausal syndrome patients without depression and normal controls, and to correlate neurophysiological with clinical and hormonal findings in order to elucidate the pathogenesis of depression in the menopause. METHODS: One hundred and twenty-nine menopausal women, aged 45-60 years, with no previous hormonal replacement therapy were investigated in regard to hormones (estradiol [E2], follicle stimulating hormone [FSH]), clinical symptomatology (Kupperman Index [KI], Hamilton depression score [HAMD]) and brain function (EEG mapping). Based on KI and DSM-III-R research criteria for major depression, 3 groups were available for statistics (after removal of protocol violators): group A had a KI of <15 and no depression (n = 29); group B had a KI of > or = 15 and no depression (n = 29) and group C had a KI of > or = 15 and fulfilled the criteria for major depression (n = 60). RESULTS: EEG maps of depressed patients demonstrated less total power and absolute power in the delta, theta and beta band, more relative delta and less alpha power as well as a slower delta/theta and faster alpha and beta centroid than controls, suggesting a vigilance decrement. Group B did not differ from group A. Correlation maps showed significant relationships between estradiol levels and EEG measures (the lower the E2, the worse the vigilance) and between the EEG measures and the Hamilton depression (HAMD) score (the worse the vigilance, the higher the depression score). There were no correlations between the hormones E2 and FSH and the syndromes KI and HAMD. In the target variable, the asymmetry index, depressed patients showed less alpha power over the right than left frontal lobe, whereas normal controls exhibited the opposite. Group B did not differ from group A. The frontal asymmetry index was significantly correlated with the Hamilton depression score and suggests right frontal hyper- and left frontal hypoactivation in depression. CONCLUSIONS: Although hormonal findings are not directly linked to psychic changes, low estradiol levels do contribute to a decreased vigilance at the neurophysiological level , which is in turn correlated with higher depressive and menopausal symptomatology at the behavioural level. Depression is further correlated to a right frontal hyper- and left frontal hypoactivation.

Brain↗
PubMed1996

Tibolone versus conjugated estrogens and sequential progestogen in the treatment of climacteric complaints.

OBJECTIVE: Tibolone has been shown to alleviate climacteric symptoms. This study was designed to compare the effect of tibolone (Livial, 2.5 mg daily) on different climacteric complaints and its impact on the endometrium, determined by vaginal ultrasound, with that of conjugated estrogens (Premarin, 0.625 mg daily) continuously for 6 months in combination with the progestogen medrogestone (Colpron, 2 x 5 mg daily for 12 days each month). METHODS: One hundred and twenty-nine postmenopausal women were recruited and the severity of climacteric symptoms as well as endometrial thickness were recorded at the pre-trial examination and after 1, 3, and 6 months. RESULTS: With the exception of vertigo, mood depression, mood disorder, loss of libido, and dryness of skin, where tibolone was found to be more effective than conjugated estrogens/medrogestone, climacteric symptoms improved significantly in both groups over the 6-month study period. Endometrial thickness did not increase significantly in the tibolone group, whereas in the conjugated estrogens/medrogestone group there was a highly significant increase after 1 month and still a trend towards significance after 6 months. Recurrence of vaginal bleeding occurred significantly less frequently in the tibolone group than in the comparison group. CONCLUSION: Tibolone seems to offer a complete treatment of the climacteric complaints whilst avoiding some of the problems associated with classical hormone replacement therapy.

Climacteric↗
PubMed1996

Decreased sexual interest and its relationship to body build in postmenopausal women.

OBJECTIVES: The relationship between body build, androgen levels and changes in sexual interest after menopause was investigated in 171 postmenopausal women from Vienna, Austria. METHODS: All women were interviewed using a structured questionnaire. Body build was determined by employing five absolute body dimensions and four anthropometric indices. RESULTS: Body weight, as well as the amount of subcutaneous centripetal fat (such as in the chest, waist and hip region), were statistically significantly related to the degree of reduced sexual interest. Corpulent and heavy women suffered far more frequently from a severe decrease in sexual interest after menopause. Statistically significant associations between androgen levels and decrease in sexual interest could not be demonstrated. CONCLUSIONS: Reduced sexual interest is associated with a kind of body type not corresponding to the culture-specific beauty ideals of our society, first of all evident in women whose menopause occurred relatively early.

Adult↗
PubMed1996

Poststroke rehabilitation in older Americans. The Medicare experience.

OBJECTIVES: This study examines the poststroke rehabilitation experience for a 20% sample of Medicare patients age 65 years and older admitted to an acute-care hospital with a stroke diagnosis during the 6-month interval, January 1, 1991 to June 30, 1991. Their Medicare claims data are used for two purposes: to identify current poststroke rehabilitation practice in the US population age 65 years and older, and to evaluate the importance of practice variation within this population. METHODS: Regarding the first objective, the authors develop estimates for many poststroke rehabilitation use and cost parameters that formerly were unmeasured. With respect to the second objective, the authors construct and compare average service use rates across all stroke patients in a census division and across all stroke patients residing in the 30 largest metropolitan statistical areas. RESULTS: The authors' Medicare claims analysis indicates that 73% of stroke survivors received either postacute institutional or ambulatory rehabilitation care during the first 6 months poststroke. The published stroke literature, on the other hand, focuses on the minority of stroke survivors, 16.5% in the Medicare data, who were admitted to an inpatient rehabilitation hospital. Regarding the second study objective, the Medicare analysis provides graphic evidence that poststroke rehabilitation practice varies substantially from one geographic area to another and that practice differences translate into large geographic-related differences in the cost of poststroke rehabilitation. CONCLUSIONS: The authors believe the findings demonstrate a problem with inconsistent poststroke rehabilitation practice.

Aged↗
PubMed1996

The effects of estradiol valerate plus medroxyprogesterone acetate and conjugated estrogens plus medrogestone on climacteric symptoms and metabolic variables in perimenopausal women.

BACKGROUND: Two sequential hormone replacement regimens, containing either estradiol valerate plus medroxyprogesterone acetate (E2V/MPA) or conjugated estrogens plus medrogestone (CE/MED), were compared with respect to effects on climacteric symptoms, lipid metabolism, and hemostasis. METHODS: In an open, multicenter study, 51 perimenopausal women were randomized to E2V/MPA and 50 to CE/MED. Assessment of climacteric complaints was performed at baseline and at months 1, 3, and 6. The effects on lipid and hemostatic variables were measured at baseline and at month 6. Quantitative data were analyzed using analysis of variance, the paired t-test or the chi2 Mantel-Hanszel test, where appropriate. RESILTS: Efficacy regarding treatment of climacteric symptoms was with E2V/MPA as good as with CE/MED, with a statistically significant reduction of most symptoms in both groups. After 6 months, total cholesterol and triglycerides had remained unchanged in both groups. High-density lipoprotein cholesterol showed no significant change with E2V/MPA, whereas an increase was noted in the CE/MED group (p<0.05). Low-density lipoprotein cholesterol was decreased with E2V/MPA (p<0.01) and was unchanged in the CE/MED group. Hemostatic parameters showed no significant changes after 6 months, with the exception of a decreased prothrombin time with E2V/MPA (p<0.05). Acceptability was excellent, expressed by the low incidence of treatment-related drop-outs in both groups. CONCLUSIONS: E2V/MPA is a one tablet per day sequential HRT regimen, which is as effective and acceptable as hormone replacement therapy with CE/MED regarding treatment of climacteric symptoms. Neither preparation had negative effects on lipid metabolism and hemostatic variables.

Adult↗