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Biomedical subjects

D Meschede

Publications and source records attributed to D Meschede.

At least 55 records · Page 3Linked to original sources
PubMed1995

Genetic risk in micromanipulative assisted reproduction.

The empirical data on pregnancy outcome after intracytoplasmic sperm injection (ICSI) are encouraging, but still insufficient to rule out definitely adverse genetic or teratological effects. We analyse potential adverse effects of ICSI by applying general principles of genetic and teratological risk assessment. The role of gamete micromanipulation as a possible teratogen is discussed. We consider whether ICSI patients are at increased risk for carrying and propagating genetic lesions of different kinds. The possible interference of ICSI with genomic imprinting and pre-zygotic sperm selection is reviewed and we discuss the potentially protective role of DNA repair in oocytes. Considering the available empirical data and the conclusions from our theoretical analysis it appears that neither lassitude nor over-concern about adverse effects of ICSI are justified.

Congenital Abnormalities↗
PubMed1995

Congenital heart disease in the 48,XXYY syndrome.

We report on an infant with severe tetralogy of Fallot, bilateral preauricular pits, and a 48,XXYY chromosomal complement. This case and evidence collected from the literature suggest that congenital heart disease may occur in the 48,XXYY syndrome more frequently than currently appreciated.

Heart Defects, Congenital↗
PubMed1995

Smith-Lemli-Opitz syndrome diagnosed by using time-of-flight secondary-ion mass spectrometry.

We describe a rapid and sensitive method involving time-of-flight secondary-ion mass spectrometry (TOF-SIMS) for specific laboratory diagnosis of the Smith-Lemli-Opitz syndrome, which is characterized by massive (approximately 1000-fold) accumulation of the biosynthetic cholesterol precursor 7-dehydrocholesterol. Minute amounts of blood (1-50 microL) were extracted with n-hexane, and aliquots were analyzed by TOF-SIMS. 7-Dehydrocholesterol and its isomers were detected at 491.3 mass units ([M + 107Ag]+) and cholesterol at 495.3 mass units ([M + 109Ag]+). Quantitation of 7-dehydrocholesterol and cholesterol was achieved after saponification and addition of stigmasterol as internal standard. Whereas 7-dehydrocholesterol and isomeric dehydrocholesterol were not detectable in controls, the patients revealed concentrations ranging between 0.84 and 1.25 mmol/L. Comparison with results obtained by gas chromatography indicated that quantitation by TOF-SIMS yielded the sum of 7-dehydrocholesterol, isomeric dehydrocholesterol II, and sterol III, the latter two also being increased in the patients. Consistent with quantitation by gas chromatography, the cholesterol concentrations in the patients ranged between 1.54 and 2.12 mmol/L (controls: 6.10 +/- 1.37 mmol/L).

Cholesterol↗
PubMed1995

[Interventional therapy of inferior vena cava thrombosis in pregnancy--use of a new kind of temporary vena cava filter].

Several changes occur during pregnancy that cause hypercoagulability such as venous stasis, increased levels of clotting factors, and decreased fibrinolytic activity. Nearly half of all maternal mortality can be attributed to thromboembolic disease. Recurrent embolism from venous thrombosis in pregnancy constitutes a major diagnostic and management problem. Treatment of deep venous thrombosis by anticoagulation alone may not be sufficient to prevent fatal pulmonary embolism. Because pulmonary embolism is a potential preventable and treatable condition, early and accurate diagnosis and treatment are mandatory. Prevention can be obtained by the implantation of clips, umbrellas or vena cava filters. There are only a few reports of the use of permanent inferior vena cava filters in the prevention of pulmonary embolisation in pregnancy mostly using the Greenfield-Filter. We present the indication and efficacy of a new retrievable vena-cava filter (FCP 2002) inserted through the internal jugular veins in pregnancy in two patients, which enables them to continue pregnancy, resulting in a vaginal delivery of healthy infants near term. The safety and effectiveness of this filter-system suggests that the indication for its use might be liberalized to include prophylactic insertion of this device in patients at risk known for thromboembolic disorders.

Adult↗
PubMed1994

Familial pericentric inversion of chromosome 1 (p34q23) and male infertility with stage specific spermatogenic arrest.

We report on two infertile brothers presenting with severe oligozoospermia or azoospermia. Testicular biopsy was performed on one of them and showed spermatogenic arrest at the level of primary spermatocytes. Both brothers were found to be heterozygous for a pericentric inversion of chromosome 1 (46,XY,inv(1)(p34q23)). The inversion chromosome was inherited through the maternal line, with no indication of subfertility in the probands' mother.

Adult↗
PubMed1993

Reproductive failure in a patient with neurofibromatosis-Noonan syndrome.

We report on a 39-year-old man with neurofibromatosis-Noonan syndrome and long-standing infertility. Comprehensive testing did not uncover any significant endocrine abnormalities, but the testicular seminiferous epithelium was found to be severely compromised. While the occasional association of neurofibromatosis with signs of Noonan syndrome has been reported, reproductive failure has not been previously described in this condition.

Adult↗
PubMed1993

[Mutation in the cystic fibrosis transmembrane-regulator gene in bilateral congenital ductus deferens aplasia].

A 28-year-old man and his 27-year-old wife were investigated for infertility of 3 1/2 years' duration. There was azoospermia caused by bilateral aplasia of the vas deferens, and therefore it was planned to aspirate spermatozoa from the epididymis for the purpose of in-vitro fertilisation. As part of the diagnostic workup the man was investigated for those mutations of the cystic fibrosis transmembrane regulator (CFTR) gene which occur with undue frequency in association with aplasia of the vas deferens. Deoxyribonucleic acid (DNA) analysis revealed a typical three base deletion (delta F 508). In the wife, CFTR gene mutations were excluded with 80% probability. The likelihood of cystic fibrosis in this couple's children was accordingly estimated to be about 0.2%--an acceptable risk. Assisted fertilization in patients with bilateral aplasia of the vas deferens should not be undertaken until they have been thoroughly investigated and informed of the risks.

Adult↗
PubMed1993

Influence of three different preparation techniques on the results of human sperm morphology analysis.

Using 158 unselected semen samples the present study has analysed how the results of sperm morphology assessment were influenced by different techniques for preparing the slides for microscopic assessment. All three techniques compared, the Papanicolaou stain (PAP), the Shorr stain (SHO) and the 'wet preparations' protocol (WET) are currently recommended by the World Health Organization for use in andrology laboratories. Mean percentages of morphologically normal spermatozoa were identical on PAP and SHO slides (31.1%), but were significantly lower in wet preparations (12.3%). Wide divergence of results obtained with the three different methods was also found with respect to the percentage of sperm with head, midpiece and tail defects and two 'indices of teratozoospermia'. For the majority of parameters assessed, linear regression analysis revealed a poor correlation between evaluations of PAP, SHO and WET slides (r values ranging from 0.01 to 0.87). We conclude that only one standard method should be recommended for the preparation of morphology slides in order to ensure inter-laboratory comparability of results and to enhance the value of sperm morphology analysis for predicting fertility.

Evaluation Studies as Topic↗