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Biomedical subjects

H Rehder

Publications and source records attributed to H Rehder.

At least 73 records · Page 4Linked to original sources
PubMed1985

Quantitative histology of human fetal testes in chromosomal disease.

Morphometric studies on male gonads were performed in 35 midterm fetuses aborted after prenatal diagnosis of a chromosome anomaly and in 11 chromosomally normal controls. A significant reduction of the number and volume percentage of premeiotic germ cells was observed in the chromosomally abnormal cases. Germ cell depletion was correlated with the severity of the chromosomal disease. It was least expressed in the XYY condition. In trisomy 13 and 18, depletion lead to values of less than a half or even a fourth the values of controls. Complex anomalies with XXY or XYY in addition to an autosomal disorder showed a moderate effect on germ cell reduction. No morphological differences were observed in germ cells or in Sertoli cells in a comparative electron microscopic study. Paucity of fetal germ cells can result from impaired colonization of the gonadal ridge, from low mitotic activity, or from increased premeiotic cell loss. All three factors seem to contribute to the above findings.

Cell Count↗
PubMed1984

Prenatal diagnosis of a probable hereditary syndrome with holoprosencephaly, hydrocephaly, octodactyly, and cardiac malformations.

Following genetic counselling of a consanguineous couple because of a daughter born with peripheral hypoplasia of the left arm, ultrasonographic examination during the second pregnancy revealed marked hydrocephalus of the fetus in the 17th week of pregnancy. Pathologic examination of the female fetus disclosed severe cerebral, cardiac, and skeletal malformations including holoprosencephaly, absent corpus callosum, microphthalmia, facial clefts, tetramelic octodactyly, and cardiac defects. These findings indicate a possible genetically determined syndrome that appears to be distinct in spite of some overlap with other malformation syndromes.

Abnormalities, Multiple↗
PubMed1984

[Psychological aspects of spinal anesthesia. Vasovagal syncope and anxiolytic medication].

In 61 male and female patients, the influence of the preoperative emotional state on vasovagal syncopes and anxiolytic medication during spinal anaesthesia for elective orthopaedic surgery was investigated. Male patients pretended to feel emotionally better than female patients, but had higher rates of anxiolytic medication and vasovagal syncopes. Patients in a bad (n = 8) and in a good emotional state (n = 3) received more anxiolytic medication than those with a mean emotional state. Vasovagal syncopes were registered in patients who pretended to feel good (n = 6), in those who felt bad (n = 4) and only in one patient of the mean group. The factors anxiety and depression were the most responsible for this result. The importance of coping-mechanisms for the development of psychological and psychophysiological reactions is discussed. Vasovagal syncope is interpreted as a psychophysiological reaction. In consequence it needs psychoprophylaxis.

Adolescent↗
PubMed1984

Clinical and cytogenetic studies in a large (4;8) translocation family with pre- and postnatal Wolf syndrome.

Partial deletion of 4p (Wolf syndrome) is reported in two cases resulting from paternal balanced t(4;8)(p163;p231). One of them was diagnosed prenatally and aborted. Autopsy revealed dysmorphic face, and malformed heart and kidneys. The other case, the mentally retarded sister, had no clinical signs of internal malformations, only slightly dysmorphic appearance. We concluded that loss of the terminal segment of 4p(4p163) seems sufficient to produce the clinical entity of Wolf syndrome, and partial trisomy of the short arm of chromosome 8 did not mask the 4p- phenotype. Segregation analysis showed risk figures of about 15% for a malformed child comparable to previously given figures concerning the outcome of autosomal reciprocal translocations.

Abnormalities, Multiple↗
PubMed1983

Prenatal diagnosis, fetal pathology and cytogenetic analysis of a 46,XX/47,XX, + 15 mosaic.

Mosaic trisomy 15 was prenatally diagnosed on amniotic fluid cells from two consecutive amniocenteses and was confirmed on cells from five different fetal tissues. The proportion of normal versus trisomic cells was consistently higher in the amniotic cell cultures and--with one exception--in the fetal tissues, while serial subcultures gave different results. The slightly atypical external features and internal malformations of the affected fetus as compared to the only clinical observation from the literature are not unusual enough to allow the delineation of a specific malformation pattern.

Abortion, Therapeutic↗
PubMed1983

Down's syndrome in the male. Reproductive pathology and meiotic studies.

Studies on testicular histology and meiosis were carried out by the use of light and electron microscopy in an 18-year-old Down's syndrome male in an attempt to follow the fate of the extra chromosome 21 and to evaluate the effects of this condition on spermatogenesis and the reproductive functions. The histological changes in the testes corresponded to spermatogenic arrest. Electron microscopic whole-mount spreadings of meiotic cells in the pachytene stage showed that in most nuclei an extra chromosome 21 was not detectable. Only in a small number of nuclei, univalents or trivalents with segmental pairing structures of an extra chromosome could be discovered. In contrast, the great majority of (C-banded) diakinesis figures showed the presence of a supernumerary G (no. 21) chromosome. The absence of a traceable extra chromosome 21 in most pachytene cells is explained by the assumption that it is intimately connected with and hidden in the sex vesicle, whose complex structure does not allow the identification of single elements. Strong support for this assumption is seen (a) in the general tendency of narrow spatial association of unpaired segments with the XY complex and (b) in close structural similarities occurring between univalents or nonsynapsed segments of trivalents and the nonpaired segments of the sex chromosomes. It is suggested that the association or connection of an extra chromosome with the XY complex during pachytene interferes with the phenomenon of X inactivation. In animal systems such abnormal interference is related with spermatogenic breakdown and, in a general way, with male hybrid type sterility. So far, the range of sterility vs. fertility in cases of male Down's syndrome is not yet fully clear, but it appears that impairment of fertility, and sterility are most frequent. If so, it is proposed that the effect of the trisomy 21 condition on spermatogenesis (and fertility) is a consequence of the behavior of the extra chromosome in the meiotic prophase.

Adolescent↗
PubMed1982

Fetal manifestation of a chromosomal disorder: partial duplication of the long arm of chromosome 5 (5q33 to qter).

Two live-born children and one fetus were found to be affected by autosomal imbalance consisting of a partial duplication of the long arm of chromosome 5 (5q33 to qter) and partial deficiency of the short arm of chromosome 8 (8p23 to pter), resulting from segregation of a paternal translocation heterozygote t(5;8) (q33;p23). The phenotype of the children was rather similar to that of the fetus. The main features included craniofacial dysmorphia consisting of downward slant of eyelids and corners of the mouth, flat and widened nasal bridge, prominent philtrum, and small mandible. Ventricle and atrium septum defects were associated with overriding aorta and right heart hypertrophy in all three. Statomotoric retardation was evident postnatally in the two children. This observation indicates that structural autosomal imbalance may produce a fetal phenotype that is specific for the karyotype and comparable to that seen in the newborn.

Chromosome Aberrations↗
PubMed1981

Prenatal morphology in Meckel's syndrome.

Prenatal morphology of Meckel's syndrome was studied in five fetuses of different gestational age, that had been aborted because ultrasonography and elevated amniotic AFP-levels indicated neural tube defect. Histologically, the enlarged polycystic kidneys were completely alike with respect to the type of involvement and differed only in the severity of changes. They could be identified at type III cystic kidneys according to the classification of Potter. Proliferation of hepatic bile ducts and slight cystic dilatation of pancreatic ducts is already evident in the youngest fetus. Additional cyst formation in the epididymis was found in one of the cases. Occipital encephalocele, located within an apical occipital bone defect was always associated with a second mostly occult encephalocele protruding through a separated defect of the basal occipital squame and of the first and second vertebral arch. It is assumed that double encephalocele represents a constant finding in Meckel's syndrome, indicating a specific pattern within the disturbance of neural tube closure.

Abnormalities, Multiple↗
PubMed1981

Pathology of trisomy 21--with particular reference to persistent common atrioventricular canal of the heart.

While certain external anomalies are specific and almost constant features in Down's syndrome, internal anomalies seem to be more variable in terms of frequency and severity. They may affect any organ system and are more often of minor clinical significance. However, severe malformations may occur. When they affect the cardiovascular system, postnatal survival is impaired, which is responsible for a distinctly higher incidence of cardiac and other malformations in younger children or neonates with Down's syndrome. Fetuses with trisomy 21 at midterm pregnancy show even more frequent manifestation of developmental disorders suggesting an increased spontaneous abortion rate in the second half of pregnancy. The analysis of malformations and minor anomalies in Down's syndrome compared to those of other chromosomal aberrations shows no absolute specificity but a tendency for certain developmental disturbances. These are characterized not so much by the organ system involved, but much more by the time in which the disturbance of a developmental process becomes evident, thus influencing type and localization of an anomaly. Particular reference is made to anomalies of the cardiovascular and cerebral system.

Autonomic Nervous System↗