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Biomedical subjects

A Albrecht

Publications and source records attributed to A Albrecht.

At least 19 recordsLinked to original sources
PubMed1997

Effect of hormone replacement therapy on growth hormone stimulation in women with premature ovarian failure.

OBJECTIVE: To assess the effect of oral hormone replacement therapy (HRT) on body weight, insulin-like growth factor I (IGF-I), and GH response to exogenous GHRH [corrected] in women with premature ovarian failure (POF) [corrected]. DESIGN: Controlled clinical study. SETTING: Outpatients studied in the department of endocrinology of the University Hospital in Vienna. PATIENT(S): Twenty-four women with POF (study group) and 24 volunteers with normal ovarian cycles (control group). INTERVENTION(S): Pituitary GHRH [corrected] stimulation was performed in all women at study entry and in patients with POF after 1, 6, and 12 months of standard oral HRT. Blood samples were collected from 15 minutes before to 120 minutes after GHRH administration [corrected]. Body weight also was evaluated. RESULT(S): No differences in baseline and stimulated serum GH were found either between POF women and controls or in POF women during HRT. Women with POF without HRT had significantly higher IGF-I levels; a reduction in circulating IGF-I levels occurred during HRT. Body weight remained stable. CONCLUSION(S): Our results show the following: [1] Women with POF have similar Gh secretion patterns as healthy age-matched women; [2] physiologic HRT has no impact on GHRH-induced [corrected] GH stimulation; and [3] HRT has no impact on body weight in women with POF.

Adult↗
PubMed1997

Androgen serum levels in women with premature ovarian failure compared to fertile and menopausal controls.

OBJECTIVE: The purpose of our study was to examine androgen serum levels and bone density in women with premature ovarian failure (POF) compared to healthy normal controls. STUDY DESIGN: Thirty-three women 19-35 years of age with idiopathic POF were compared to 33 well-matched women with normal ovarian function and 32 healthy postmenopausal (PMP) women concerning 17-hydroxyprogesterone (17-OHP), androstendione (A), testosterone (T), dehydroepiandrosterone-sulfate (DHEAS), insulin-like growth factor 1 (IGF-1), as well as bone density (BD). RESULTS: Women with POF showed statistically significantly lower concentrations of 17-OHP, A, T (p < 0.001) and a reduced bone density (p < 0.001) compared to fertile controls. No differences were found between POF and PMP women concerning estradiol (E2), T, A and 17-OHP. Regarding DHEAS, no statistically significant differences were found between women with POF and fertile controls whereas PMP women proved to have significantly lower DHEAS concentrations than fertile controls. Women with POF had the highest IGF-1 serum concentrations and PMP women the lowest. CONCLUSION: An important decrement of ovarian steroids and bone density was noticed in women with POF, while the time since menopause had no influence on androgen concentrations. The hormone concentrations in women with POF are similar to those observed in normal PMP women with the exception of DHEAS and IGF-1 levels.

Adult↗
PubMed1997

Masseter muscle rigidity and nondepolarizing neuromuscular blocking agents.

Masseter muscle rigidity has been identified as a possible risk factor for malignant hyperthermia (MH) and is usually noted in children receiving intravenously administered succinylcholine chloride after mask induction with halothane. Nondepolarizing muscle relaxants are considered safe for persons susceptible to MH. In this article, we present a case of clinically recognized jaw rigidity in the absence of succinylcholine after administration of a non-depolarizing muscle relaxant that was reported to the Malignant Hyperthermia Association of the United States hot line. The patient had recurrent jaw rigidity during subsequent anesthesia when a different non-depolarizing muscle relaxant was given. The North American MH Registry was then reviewed for similar cases. Three cases of masseter muscle rigidity in the presence of nondepolarizing muscle relaxants were discovered. Two of the patients were not found to be susceptible to MH; however, the third patient had positive findings on muscle biopsy. These cases do not provide enough information to confirm the ability of nondepolarizing muscle relaxants to cause jaw rigidity in the absence of MH.

Adult↗
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

Initial steps of sophoroselipid biosynthesis by Candida bombicola ATCC 22214 grown on glucose.

Candida bombicola ATCC 22214 produces the glycolipid sophoroselipid when cultivated on a medium with glucose as the sole carbon source. Under phosphate-limiting conditions the product yield rises from 0.033 to 0.143 and the specific product formation rate rises from 0.004 h-1 to 0.007 h-1. Enhanced sophoroselipid synthesis is initiated by the decline of the specific activities of NAD- and NADP-dependent isocitrate dehydrogenase (EC 1.1.1.41 and 1.1.1.42) to 2% and 0% of the initial activities respectively. Constantly high specific activity of citrate synthase (EC 4.1.3.7) causes an accumulation of isocitrate and citrate in the mitochondria. Both acids are transported into the cytosol where citrate is cleaved by ATP: citrate lyase (EC 4.1.3.8) giving rise to acetyl-CoA, the precursor of fatty acid synthesis. The ATP: citrate lyase is unaffected by different energy charges; the apparent K(m) values for coenzyme A, ATP and citrate are 23 microM, 250 microM and 256 microM respectively. NADPH for fatty acid synthesis might be generated by further metabolism of oxaloacetate, the other product of the citrate-cleaving reaction, by oxidation of the isocitrate by the cytosolic NADP-dependent isocitrate dehydrogenase or via the hexose monophosphate shunt. A possible explanation for sophoroselipid formation during exponential growth is given.

Adenosine Monophosphate↗
PubMed1996

[Doppler ultrasound in cases of Rhesus incompatibility. Effect of intravascular punctures with or without transfusion on feto-placental Doppler blood flow velocity curves].

OBJECTIVE: To investigate the influence of cordocentesis with or without blood transfusion on umbilical and fetal blood flow characteristics. METHODS: Of 42 pregnant women suffering from Rh. incompatibility 15 had a puncture of the umbilical cord for diagnostic reasons only. In 27 cases a total of 86 punctures was done for blood transfusion. Fetal heart rate, umbilical artery A/B Ratio and Pulsatility Index (PI) in the fetal aorta were measured before and after cordocentesis in all cases having or having not a transfusion. RESULTS: Diagnostic and therapeutic cordocentesis resulted in a slight decrease of peripheral resistance. Significant differences were only observed in cases with a haematocrit < 20% compared to cases with values > 40% or if the final haematocrit after transfusion resulted in a value of < 30%. CONCLUSION: The decrease peripheral resistance in cases of therapeutic cordocentesis can be attributed to the increase in blood volume and sufficient oxygenation of blood improving fetal perfusion. Doppler sonography is not helpful in the clinical management of red blood cell immunisation.

Adult↗
PubMed1996

Local cholinergic mechanisms mediate nitric oxide-dependent flow-induced vasorelaxation in vitro.

To determine whether local cholinergic mechanisms evoke nitric oxide (NO)-mediated flow-induced vasorelaxation, canine coronary artery rings without endothelium were suspended beneath an organ chamber that contained a stainless steel tube and a femoral artery segment with endothelium. The rings were superfused at a basal rate of 1 ml/min with physiological salt solution that was bubbled with 95% O2-5% CO2 and maintained at 37 degrees C. They were stretched to optimal length and contracted with prostaglandin F 2 alpha (2 x 10(-6) M). When flow through the stainless steel tube (direct superfusion) was increased from the basal rate of 1 to 4 ml/min, coronary force did not change. Superfusion of the rings (n = 8) with effluent from the femoral segment (endothelial superfusion) at 4 ml/min to study flow-induced vasodilation caused a 67.3 +/- 10.8% relaxation. Treatment of the segment with the NO synthase blocker NG-monomethyl-L-arginine (10(-4) M) eliminated the relaxation seen during endothelial superfusion (P < 0.05 vs. control). Application of atropine (10(-6) M) to additional femoral segments (n = 8) abolished the coronary relaxation observed during endothelial superfusion at 1 ml/ min, and the flow-induced relaxation observed at 4 ml/min was reduced from 64 +/- 8.3 to 27 +/- 5.6% (P < 0.05 vs. control). In studies on additional segments and rings (n = 6), the flow-induced relaxations at 4 ml/min of endothelial superfusion were blunted from 86 +/- 10 to 28 +/- 13% after the segments were treated with acetylcholinesterase (0.00028 U/min for 20 min). These data indicate that basal- and flow-induced release of NO from the vascular endothelium can be mediated by local cholinergic mechanisms. It is possible that flow causes acetylcholine release from certain endothelial cells, which stimulates NO release from these cells or from neighboring endothelial cells.

Acetylcholine↗
PubMed1995

Effects of hormone replacement therapy on growth hormone secretion patterns in correlation to somatometric parameters in healthy postmenopausal women.

OBJECTIVES: The aim of the present study was to investigate the influence of a continuous estrogen, cyclic progesterone replacement therapy on the secretion of growth hormone (GH) and IGF I as well as of somatometric-GH correlation patterns. METHODS: The study included 23 healthy postmenopausal women. Of the proband group 13 randomly selected women were treated with orally applicated 2 mg estradiol-valerat (E2V) and 10 mg dydrogesterone for 10 months. Ten women did not receive any hormonal treatment during this time. After 10 months all probands were reexamined and their GH and IGF I secretion, as well as their somatometric-hormonal correlation patterns, compared with those of a fertile control group. RESULTS: It could be shown, that in postmenopausal women a 10-month oral hormone replacement therapy led to a significant increase of GH- and IGF I levels, however, the treated postmenopausal women did not reach the levels of the fertile controls. Those women who did not receive any hormonal treatment and the postmenopausal women before HRT showed nearly identical GH- and IGF I levels as well as somatometric-GH correlation patterns. CONCLUSIONS: The results of the present paper indicate a marked influence of estrogens on GH and IGF I secretion. Furthermore, hormonal replacement therapy (HRT) may influence somatometric GH correlation patterns too.

Adult↗
PubMed1995

Hysterectomy increases the symptomatology of postmenopausal syndrome.

The purpose of our investigation was to verify whether or not women who have undergone hysterectomy react differently to the menopause compared with women who have not. The study was performed in a prospective documentation on 203 women, and the assessments of discomforts were provided by the patients themselves using questionnaires. For statistical purposes, the Mann-Whitney test and chi 2 test were used. In both groups of patients--with and without hysterectomy--a determination was made concerning the significance of differences in the degree of intensity of problems: breast tension (p < 0.05), muscle pains (p < 0.05), palpitations (p < 0.05) and dizziness (p < 0.01). Concerning the frequency of climacteric symptoms, a significant difference was noted for urogenital ailments. While only 29.6% of women who had not been operated on complained about discomfort caused by atrophy of the urogenital tract, the number of women with such discomfort who had had a hysterectomy was 42.6% (p < 0.01). In other words, women who underwent hysterectomy suffered more discomfort and showed frequent symptoms of urogenital atrophy.

Anxiety↗
PubMed1994

The mutator gene swi8 effects specific mutations in the mating-type region of Schizosaccharomyces pombe.

The swi8+ gene of Schizosaccharomyces pombe appears to be involved in the termination step of copy synthesis during mating-type (MT) switching. Mutations in swi8 confer a general mutator phenotype and, in particular, generate specific mutations in the MT region. Sequencing of the MT cassettes of the h90 swi8-137 mutant revealed three altered sites. One is situated at the switching (smt) signal adjacent to the H1 homology box of the expression locus mat1:1. It reduces the rate of MT switching. The alteration at the smt signal arose frequently in other h90 swi8 strains and is probably caused by gene conversion in which the sequence adjacent to the H1 box of mat2:2 is used as template. This change might be generated during the process of MT switching when hybrid DNA formation is anomalously extended into the more heterologous region flanking the H1 homology box. In addition to the gene conversion at mat1:1, two mutations were found in the H3 homology boxes of the silent cassettes mat2:2 and mat3:3.

Base Sequence↗
PubMed1994

Absorption of orally supplied natural estrogens correlated with age and somatometric parameters.

The plasma levels of estradiol were studied in 20 postmenopausal women over a period of 8 h following the ingestion of a single dose of 2 mg estradiol valerate and 2 mg micronized estradiol. The determined plasma estradiol concentrations were correlated with somatometric characteristics and age. Twenty-six postcephalic body measurements, the body weight and six skin-fold thickness measurements were taken and the body mass index computed; estradiol serum concentration was measured before and after administration of micronized estradiol and estradiol valerate, respectively. It was shown that estradiol concentrations obtained after estradiol valerate and micronized estradiol ingestion were dependent on the patient's age as well as on the constitutional type. Additionally, we found that there were differences in the reachable estradiol plasma concentrations following the application of the two preparations. Our results justify the individual and differentiated estrogen replacement therapy of the postmenopausal woman.

Administration, Oral↗
PubMed1993

A simple and inexpensive high density dialysis tubing cell culture system for the in vitro production of monoclonal antibodies in high concentration.

This paper describes the construction and application of a low-cost roller bottle-like culture appliance in which hybridoma cells can be cultivated in high density in dialysis tubing. The appliance facilitates the simultaneous culture of up to four cell lines yielding 50 ml culture volume of each. Samples for follow-up analysis of the cultures can easily be taken when needed through sample ports. In order to obtain high cell densities (at least 10(7) cells/ml), high cell viability (at least 50%) and high antibody yield (at least 1.0 mg/ml) the bottle is rolled at a speed of 4-6 rpm and is gassed continuously by a micropump driven by rechargeable NiCd batteries fixed to the culture flask. Depending on the individual properties of the hybridoma lines tested, the cells may be cultured for 1-2 weeks, and cell densities of up to 30 x 10(6) cells/ml with viabilities of approximately 50% and monoclonal antibodies in concentrations of up to 2.8 mg/ml may be obtained. In their properties the monoclonal antibodies produced by this in vitro procedure are indistinguishable from those prepared in the form of conventional stationary culture supernatant or of ascitic fluid. Specific antibody content is within the same range as in ascitic fluid. Consequently, the monoclonal antibodies can be purified in one step, e.g., by ion exchange chromatography from the culture supernatant. Therefore, the newly developed culture device and the culture method described is a useful alternative to ascites production in live mice.

Animals↗
PubMed1993

[Mediastinal chloroma with right heart involvement. Unusual cause of a superior vena cava syndrome].

For four months a 28-year-old man had been suffering from a sensation of pressure in his head when lying down, swelling of the face, exertional dyspnoea and weight gain of 9 kg. Biochemical tests and chest radiograph were unremarkable. Echocardiography revealed a 3 x 5 cm mass in the right atrium, extending into the superior vena cava whose lumen was narrowed to a few millimetres. Computed tomography and magnetic resonance imaging were suggestive of a malignant tumour. Bone marrow biopsy as well as transvascular and mediastinoscopically obtained biopsies failed to provide a pathological diagnosis. Exploratory thoracotomy uncovered a nonresectable chloroma surrounding both venae cavae. It had penetrated into the right and left atria, as well as the pulmonary veins. A Gore-tex bypass was placed between the innominate vein and right atrial appendage. The tumour was identified as a local manifestation of acute myeloid leukaemia. Treatment with idarubicin (12 mg/m2 daily for 3 days) and adriamycin (1.5 mg/m2 daily for 4 days) followed by radiotherapy with 35 Gy achieved partial remission and 15 months after onset of treatment the patient is in a good general condition.

Adult↗
PubMed1993

An automatic dehydrogenase-based flow-injection system: application for the continuous determination of glucose and lactate in mammalian cell-cultures.

A concept for the development of an automatic flow-injection analyzer with integrated dehydrogenase columns and its application in the control of industrial processes is presented. The system is based upon a kernel consisting of a nested-loop injection unit, pumps for the filling of the injection loops and the transport of buffer and values for switching on the one hand between sample and standard solutions and on the other hand between different enzyme columns. A Microsoft Windows 3.x application 'WIN-FIA' controls interactively the whole system and can be easily adapted to a specific solution of an analytical problem. As an example, the flow-injection system was used for the continuous determination of glucose and lactate, using glucose dehydrogenase (GDH) and lactate dehydrogenase (LDH) as indicator enzymes, in a mammalian cell-culture fermentation process. The resulting concentration values are in good agreement with those obtained by discontinuously taken standard spectrophotometric enzyme assays.

Animals↗
PubMed1993

Intestinal vitamin A metabolism: coordinate distribution of enzymes and CRBP(II).

In the mucosal layer of the small intestine, we found nearly identical gradients of CRBP(II), retinal reductase, and LRAT levels down the duodenal-ileal axis, suggesting coordinate regulation of these three proteins. In all cases the level of binding protein or enzyme activity was greatest in the proximal intestine and then decreased sharply in the distal half. This pattern fits with the known capacity of the intestine to absorb vitamin A. In addition, the retinal reductase activity was found predominantly in the intestinal mucosa, while LRAT activity was found in both the intestinal mucosa and muscle. An even distribution of LRAT activity along the longitudinal axis of the intestinal muscle was consistent with an even distribution of CRBP in that tissue. In conjunction with LRAT activity and CRBP, we found endogenous retinyl ester stores in the intestinal muscle layer. The patterns of retinyl ester produced by LRAT in vitro and found in vivo were similar, with retinyl palmitate predominating and a high percentage comprised of retinyl stearate. We also observed a bile salt-independent retinyl ester hydrolase activity in intestinal muscle whose distribution paralleled the retinyl ester stores and LRAT levels. This hydrolase appears to be distinct from retinyl ester hydrolases described from other organs as its activity was insensitive to retinyl ester chain length, the presence of bile salts, or the addition of apo-CRBP. This activity was inhibited by diethyl-p-nitrophenyl-phosphate (IC50 100 microM) and diethylpyrocarbonate (IC50 10 microM), demonstrating a requirement for active serine and histidine residues. In addition, we describe an activity present in some intestinal microsomal preparations that can perturb determinations of reductase and LRAT activity and must be avoided.

Acyltransferases↗