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Biomedical subjects

M Ludwig

Publications and source records attributed to M Ludwig.

At least 163 records · Page 9Linked to original sources
PubMed1998

The effect of multiple cryopreservation procedures and blastomere biopsy on the in-vitro development of mouse embryos.

Preimplantation genetic diagnosis is currently used in clinical practice. In experienced hands the biopsy procedure alone does not affect the further in-vitro and in-vivo developmental potential of animal and human embryos. No data exist on the combination of cryopreservation of embryos at the pronuclear and/or 8-cell stage and/or biopsy at the 8-cell stage. Pronuclear stages of mouse F1 hybrids (C57Bl/jxCBA) were harvested and divided into several experimental groups. The developmental rates of zygotes, which were neither biopsied nor cryopreserved were used as data control. Others were only cryopreserved at the pronuclear stage (C-PN), or at the cleavage stage (C-CS), or both. Each of these groups was also combined with or without a biopsy. Only the hatched blastocyst rate (HBR), but not the 'simple' blastocyst rate, showed significant differences between groups. Neither C-PN (HBR = 60.42%), nor C-CS (63.16%), nor a combination of both (59.46%) had an impact on the hatched blastocyst rate when compared with that of the control group (67.46%). The biopsy procedure (55.93%) also proved not to be harmful for the embryos. The embryos, which were C-PN and C-CS, and subsequently biopsied, showed a significantly lower hatched blastocyst rate (39.62%) than that of the control, C-PN, C-CS, and C-PN/C-CS groups (P < 0.05). The combination of C-PN and cleavage-stage biopsy also lead to a lower hatched blastocyst rate (42.22%), compared with that of the control group (P < 0.05). It was concluded that couples must be advised that an effect on embryos which have undergone a combined cryopreservation and micromanipulation procedure cannot be ruled out. However, cryopreservation at the pronuclear or at the 8-cell stage alone, or in combination with a biopsy procedure, does not influence the further development of the embryo.

Animals↗
PubMed1998

Interactions between trophoblast and uterine epithelium: monitoring of adhesive forces.

At embryo implantation, it is postulated that the initial contact between blastocyst and maternal tissues is by adhesion of the trophoblast to the uterine epithelium. This cell-to-cell interaction is thought to be critical for implantation, although the actual adhesive forces have never been determined. In the present study, the atomic force microscope (AFM) was used to study the adhesion between human uterine epithelial cell lines (HEC-1-A; RL95-2) and human trophoblast-type cells (JAR). Specific interaction forces of these epithelia via their apical cell poles were determined on the basis of approach-and-separation cycles. For this purpose, the AFM tip was functionalized with JAR cells, then brought to the surface of uterine epithelial monolayers and was kept in contact for different periods of time (ms, 1, 10, 20, 40 min). The approach force curves displayed repulsive interactions for both HEC-1-A and RL95-2 cells. However, RL95-2 cells (with a smooth surface structure and a thin glycocalyx) showed lower values of the repulsive regime than HEC-1-A cells (with a rough surface structure and a thick glycocalyx). After having overcome repulsive interactions, the initial contact was followed by adhesive interactions. For contact times of 20 and 40 min, RL95-2 cells, but not HEC-1-A cells, showed specific JAR binding, i.e. the separation force curves displayed repeated rupture events in the range of 1-3 nN with a distance between 7-15 microm and, thereafter, a final rupture event at a distance of up to 45 microm. These features point to the formation of strong cell-to-cell bonds. Collectively, these studies provide the first definition of interaction forces between the trophoblast and the uterine epithelium, and are consistent with the hypothesis that an RL95-2-like architecture of uterine epithelial cells, i.e. an non-polarized phenotype, is essential for apical adhesiveness for the human trophoblast.

Cell Adhesion↗
PubMed1998

Treatment of uterine fibroids with a slow-release formulation of the gonadotrophin releasing hormone antagonist Cetrorelix.

A depot preparation of the third-generation gonadotrophin-releasing hormone (GnRH) antagonist Cetrorelix (SB-75) was used for preoperative treatment in twenty premenopausal patients with symptomatic uterine fibroids who were to undergo surgery. In a prospective, open, randomized setting 60 mg of Cetrorelix pamoate salt was administered i.m. on cycle day 2. Patients were randomized for a second dose of 30 or 60 mg of Cetrorelix depot, which was administered according to the degree of oestradiol suppression (<50 pg/ml) on treatment day 21 or 28. Surgery was done after 6 or 8 weeks of treatment, depending on second dosage administration. Weekly transvaginal sonography (TVS) and magnetic resonance imaging (MRI) before and after treatment was performed, for fibroid volume assessment. Sixteen patients showed satisfactory suppression of gonadotrophins and sex steroid secretion, avoiding any initial flare-up effect. In these patients a mean shrinkage rate of largest fibroid volume of 33.5% at the end of treatment could be observed according to TVS, while the mean shrinkage rate obtained after 14 days of treatment was 31.3%. In good responders (shrinkage >20%) largest fibroid volume at day 14 was approximately 56.7% of basic assessment. Although MRI showed minor mean shrinkage rates of only 25.4% of the initial volume, these differences in comparison to TVS assessment were not statistically significant. The avoidance of any initial flare-up in gonadotrophin secretion may explain this extremely fast reduction in fibroid size. The advantages of GnRH antagonist treatment in this indication consist in the short treatment time with a fast restoration of the ovarian function. The rate of poor responders may be reduced by using an improved slow release preparation.

Adult↗
PubMed1998

Ovarian hyperstimulation syndrome (OHSS) in a spontaneous pregnancy with fetal and placental triploidy: information about the general pathophysiology of OHSS.

An ovarian hyperstimulation syndrome (OHSS) in spontaneous pregnancies is a very rare event. Hence, clinicians might make wrong decisions, such as laparotomy, because of suspicion of an ovarian carcinoma, or severe complications such as renal insufficiency may develop because the diagnosis and treatment of OHSS are delayed. Here we report a case of a woman in the 15th week of gestation, presenting with a partial hydatidiform mole and a triploidy of fetus and placenta, with an ongoing and severe OHSS even after legal induced abortion. A low vascular endothelium growth factor (VEGF) concentration (50 ng/ml) was measured when human chorionic gonadotrophin (HCG) exceeded 1000 IU/l and was followed by VEGF concentrations >900 ng/ml, when the OHSS developed. The literature on spontaneous pregnancies associated with OHSS is reviewed, and possible reasons for the clinical course presented in this study and the reviewed reports are discussed. The findings in this case contribute to our theory that VEGF is a causative factor of OHSS, but has no impact on the course of this disease.

Abortion, Induced↗
PubMed1998

Patient assessment in chronic prostatitis.

Assessment of men suffering from proven chronic prostatitis involves a cascade of diagnostic steps, including evaluation of symptoms and clinical features, objectivation of the inflammatory response in expressed prostatic secretions, standardized localization techniques for common bacteria and a search for fastidious, uncommon pathogens.

Journal Article↗
PubMed1998

Expression of tobacco carbonic anhydrase in the C4 dicot flaveria bidentis leads to increased leakiness of the bundle sheath and a defective CO2-concentrating mechanism

Flaveria bidentis (L.) Kuntze, a C4 dicot, was genetically transformed with a construct encoding the mature form of tobacco (Nicotiana tabacum L.) carbonic anhydrase (CA) under the control of a strong constitutive promoter. Expression of the tobacco CA was detected in transformant whole-leaf and bundle-sheath cell (bsc) extracts by immunoblot analysis. Whole-leaf extracts from two CA-transformed lines demonstrated 10% to 50% more CA activity on a ribulose-1,5-bisphosphate carboxylase/oxygenase-site basis than the extracts from transformed, nonexpressing control plants, whereas 3 to 5 times more activity was measured in CA transformant bsc extracts. This increased CA activity resulted in plants with moderately reduced rates of CO2 assimilation (A) and an appreciable increase in C isotope discrimination compared with the controls. With increasing O2 concentrations up to 40% (v/v), a greater inhibition of A was found for transformants than for wild-type plants; however, the quantum yield of photosystem II did not differ appreciably between these two groups over the O2 levels tested. The quantum yield of photosystem II-to-A ratio suggested that at higher O2 concentrations, the transformants had increased rates of photorespiration. Thus, the expression of active tobacco CA in the cytosol of F. bidentis bsc and mesophyll cells perturbed the C4 CO2-concentrating mechanism by increasing the permeability of the bsc to inorganic C and, thereby, decreasing the availability of CO2 for photosynthetic assimilation by ribulose-1,5-bisphosphate carboxylase/oxygenase.

Journal Article↗
PubMed1998

Evaluation of seminal plasma parameters in patients with chronic prostatitis or leukocytospermia.

Though detailed cytological and microbiological diagnostic procedures are routinely carried out in male genital tract infection, the correct diagnosis and localization of inflammation or infection is often difficult. In this prospective study, the relevance of the seminal plasma markers PMN elastase, complement C3, CRP, fructose, PSP 94, PSA, and alpha-glucosidase was investigated in 13 patients with chronic prostatitis, 31 patients with significant leukocytospermia, and 58 patients with non-inflammatory diseases (controls). Statistically relevant results were obtained for PMN elastase when comparing chronic prostatitis with controls, leukocytospermia with controls (P < 0.001) and chronic prostatitis with leukocytospermia (P < 0.05); for complement C3 chronic prostatitis and leukocytospermia vs. controls (P < 0.05) and for fructose/ejaculate leukocytospermia vs. controls (P < 0.05). No statistically relevant differences were found for C-reactive protein, alpha-glucosidase, PSA and prostatic secretory protein (PSP 94). To delimit genital tract inflammation from non-inflammatory patients, cutpoint levels for PMN elastase of 230 ng ml-1 and for C3c of 0.01 g l-1 were suggested. PMN elastase was shown to possess the strongest discriminating power. The assessment of a cutpoint for fructose to indicate seminal vesicle dysfunction is not possible as the significance level is weak (P < 0.05).

Adolescent↗
PubMed1998

Influence of different uropathogenic microorganisms on human sperm motility parameters in an in vitro experiment.

The influence of different uropathogenic microorganisms (E. coli, enterococcus, Pseudomonas aeruginosa, Staphylococcus saprophyticus, Candida albicans) on human sperm motility was studied in vitro with a computer-assisted sperm analyser (CASA). Native ejaculates were prepared with the swim-up technique and adjusted to 22 x 10(6) spermatozoa ml-1. The sperm suspension was artificially infected with microorganisms in concentrations varying from 2 x 10(3) to 2 x 10(7). Sperm motility was examined directly after incubation, 2, 4 and 6 h later using the Mika motion analysis, a computer-based, automatic motility analysis. Former results with E. coli (serotype 06) could be confirmed that a significant inhibitory effect on sperm motility was associated with bacterial growth. Experiments with the enterococcus strain and Staphylococcus saprophyticus indicated no significant influence on sperm motility parameters. Tests with Pseudomonas aeruginosa showed a decrease of progressive motility according to time, but not to different bacterial concentrations. A significant inhibitory effect of Candida albicans was only detected in the samples with the initial bacterial concentration of 2 x 10(7) microorganisms ml-1.

Bacteria↗
PubMed1998

Mineralocorticoid receptor splice variants in different human tissues.

The mineralocorticoid receptor (MR), a member of the steroid receptor family, acts as a transcription factor and mediates both aldosterone and cortisol effects. Aldosterone specificity in some tissues results from the inactivation of competing cortisol into cortisone by 11beta-hydroxysteroid dehydrogenase. In other tissues MR and the glucocorticoid receptor show overlapping physiological effects or may act together by forming a heterodimer. An additional MR splice variant (MR+4) has been found in different mRNA samples from rat tissues and human white blood cells, thereby implying additional modes of MR-regulated effects. We therefore looked for the presence of these two MR-mRNA isoforms in human classical aldosterone target tissues and various other tissues. MR-mRNA was found in all samples investigated, thereby showing the expression of MR to be more abundant than has been observed thus far. In addition, the MR+4-mRNA variant was also found in all the tissues examined.

Alternative Splicing↗
PubMed1998

Intrahypothalamic vasopressin release. An inhibitor of systemic vasopressin secretion?

Vasopressin and oxytocin are released into the extracellular space of the supraoptic (SON) and paraventricular nuclei (PVN). The dendrites of these neurones contain a high density of neurosecretory granules, and exocytotic profiles have been visualised by electron microscopy. Release within the SON has been measured using microperfusion techniques; release is tetrodotoxin-independent, calcium-dependent, and is activated by a range of physiological stimuli, including suckling, dehydration, haemorrhage and stress. Release of vasopressin into the SON is regulated by a number of forebrain and brainstem areas. Dendritic release does not necessarily parallel neurohypophyseal release, and may occur semi-independently of spike activity in the soma and axons. The physiological consequences of dendritic vasopressin release are not clear, vasopressin and oxytocin appear to induce further vasopressin and oxytocin release from the dendrites. In contrast, by combining retrodialysis and electrophysiology we have shown that, unlike oxytocin which excites oxytocin neurones, vasopressin inhibits the electrical activity of vasopressin neurones, and hence suppresses vasopressin release from the pituitary. Thus, vasopressin released from dendrites may act on vasopressin neurones to regulate their phasic activity by an auto-inhibitory action within the SON. Since dendritic vasopressin release is increased and prolonged after various stimuli, this mechanism may act to restrain excitation of vasopressin neurones (and hence vasopressin secretion from the neurohypophysis) during continuing stimulation.

Animals↗
PubMed1998

[Rhesus factor determination of the genome of stereomicroscopy selected amniocytes].

This study intended to develop a molecular biological method for the determination of the rhesus blood type through the genome of amniocytes. Using micropipettes amniocytes were isolated under a stereomicroscope from amniotic fluid samples. Single or several (> or = 10) amniocytes, respectively, were pipetted into 0.2 ml vials each, and were lysated at 65 degrees C for 15 min using an alkaline solution making the DNA accessible to polymerase chain reaction. Thereafter, the rhesus D gene as well as the CE gene were amplified with nested primers in two subsequent PCR. Finally, the amplification product was electrophoretically analyzed using agarose gel. When single aminocytes were analysed the amplification rate was 64% for the rhesus D gene, and 80% for the rhesus CE gene; "allele specific non amplification" was observed in 24% of cases. With 10 or more amniocytes per vial the amplification rate was 100%. This method permits to reliably predict the fetal rh-type at low costs within about 4 hours.

Amniocentesis↗
PubMed1997

Local opioid inhibition and morphine dependence of supraoptic nucleus oxytocin neurones in the rat in vivo.

1. Single neurones of the rat supraoptic nucleus were recorded during microdialysis of naloxone onto the ventral surface of the nucleus in anaesthetized rats. We used this combination of techniques to test whether the acute or chronic effects of systemically or centrally applied opioids upon oxytocin cell activity were due to actions of the opioids within the nucleus itself. 2. Supraoptic nucleus oxytocin neurones were identified antidromically and by an excitatory response to intravenously injected cholecystokinin. Acute intravenous injection of the kappa-agonist U50488H or the mu-agonist morphine (1-5 mg kg-1) reduced the firing rate of identified oxytocin neurones by 97.7 +/- 4.8% (n = 6) and 94.1 +/- 4.1% (n = 7), respectively. The inhibition by each of these opioids was completely reversed after administration by microdialysis (retrodialysis) of the opioid antagonist naloxone (0.1-1.0 microgram microliter-1 at 2 microliters min-1) onto the exposed ventral surface of the supraoptic nucleus. 3. Retrodialysis of naloxone (0.1-10.0 micrograms microliter-1) onto the supraoptic nucleus of rats made dependent by intracerebroventricular morphine infusion for 5 days increased the firing rate of oxytocin neurones from 0.9 +/- 0.4 to 3.1 +/- 0.7 spikes s-1 (P < 0.05, n = 6). This increase in firing rate from basal was 58.5 +/- 15.1% of that following subsequent intravenously injected naloxone (5 mg kg-1). 4. Thus, the acute inhibition of supraoptic nucleus oxytocin neurones which results from systemic administration of opioid agonists primarily occurs within the supraoptic nucleus itself, since the antagonist naloxone was effective when given into the supraoptic nucleus. Furthermore, oxytocin neurones develop morphine dependence by a mechanism which is distinct from an action on their distant afferent inputs. Nevertheless, withdrawal excitation of these afferent inputs may enhance the magnitude of oxytocin neurone withdrawal excitation.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1997

Haemophilia B: database of point mutations and short additions and deletions, 7th edition.

The seventh edition of the haemophilia B database lists in easily accessible form all known factor IX mutations due to small changes (base substitutions and short additions and/or deletions of <30 bp) identified in haemophilia B patients. The 1535 patient entries are ordered by the nucleotide number of their mutation. Where known, details are given on: factor IX activity, factor IX antigen in circulation, presence of inhibitor and origin of mutation. References to published mutations are given and the laboratories generating the data are indicated.

Databases, Factual↗
PubMed1997

[Endoscopic carpal tunnel ligament release--a risky current technique or a modern patient-oriented therapy].

The endoscopic release of the carpal ligament gives the opportunity to treat the carpal tunnel syndrome in a comfortable and minimal invasive way. Between 1 October 1994 and 7 May 1995, 46 patients who underwent endoscopic surgery on 55 hands were documented in a prospective study. The following results were taken from a questionnaire. There were not any complaints, or the complaints were so much diminished that complete division of the carpal ligament could be viewed as accomplished in 51 of 55 cases. There were continuing complaints in four cases, and after an additional check two patients were operated on again. The advantage of the endoscopic method is the inconspicuous scar and the reduced postoperative disablement. No complications have occurred.

Adult↗
PubMed1997

Direct hypertonic stimulation of the rat supraoptic nucleus increases c-fos expressionin glial cells rather than magnocellular neurones.

We investigated whether hypertonicity acts directly on supraoptic neurones to activate c-fos expression. Hypertonic artificial cerebrospinal fluid was infused into the supraoptic nucleus (SON) via a microdialysis probe implanted 24 h previously. The rats were decapitated after 90 min for immunohistochemistry with a Fos protein antibody. Direct hypertonic stimulation increased Fos protein expression in glial cells, identified by glial fibrillary acidic protein immunoreactivity, but not in magnocellular neurones. Similarly, with in situ hybridisation c-fos mRNA expression was predominantly seen in glial cells. Fos expression in SON neurones was stimulated by systemic hypertonicity even with a microdialysis probe in the SON, and magnocellular neurones expressed Fos after direct microinjection of cholecystokinin-8S into the SON. Thus, while direct hypertonic stimulation of SON neurones activates secretion of vasopressin and oxytocin, the c-fos gene is not activated, unlike following systemic hypertonic stimulation. This indicates that excitation of neuronal electrical and secretory activity does not necessarily lead to activation of the c-fos gene. Activation of c-fos expression in glial cells by direct hypertonic stimulation may reflect their role in regulating brain extracellular fluid composition.

Animals↗