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D K Kalousek

Publications and source records attributed to D K Kalousek.

137 records · Page 8Linked to original sources
PubMed1981

Further delineation of X-linked mental retardation.

Chromosomal, clinical, and psychological data are presented on members of six families with X-linked mental retardation. Affected males in three of these families express the fra(X)(q28) marker, while the retarded males in the other three do not. Similar variable physical and psychological characteristics, such a lop ears, large testes, and perseverative speech, are present in affected males in all six families. Preliminary analysis of the psychological data also shows that males with and without marker expression cannot be differentiated with certainty. On this basis we suggest that there is a type of X-linked mental retardation with many phenotypic features of marker-X mental retardation but without expression of the X chromosome fragile site.

Chromosome Fragile Sites↗
PubMed1981

A method for obtaining high quality chromosome preparations from single hemopoietic colonies on a routine basis.

The need for improved methodology to facilitate cytogenetic analysis of hemopoietic stem cell populations, particularly in studies of the hemopoietic malignancies, has been recognized for a number of years. Since primitive hemopoietic cells can be stimulated to form colonies of identifiable progeny under appropriate conditions in vitro, it should in theory, be possible to obtain such information. However, hemopoietic colonies of human origin rarely contain more than 1000 cells, and in handling such small samples, cell loss has historically been a major problem. We now describe a method that has allowed from two up to more than 50 metaphases per colony to be obtained from most erythroid and granulopoietic colonies harvested individually from standard methylcellulose assay cultures. Of key importance is the selection of large but still immature colonies and the use of polylysine coated slides, which ensures recovery of 80 - 90% of the sample. The method yields reproducibly high quality metaphases suitable for analysis after G, Q, and fluorescent-reverse banding. Cytogenetic analysis of 58 colonies removed individually from cultures initiated with a mixture of male and female cells showed both male and female colonies to be present as expected. In all instances only one type of metaphase was ever found in a single colony. A procedure for measuring the incidence of sister chromatid exchange (SCE) in the progeny of primitive hemopoietic progenitors has also been established. SCE values obtained for 1-2-week-old colonies derived from normal progenitors were similar to previously published normal SCE values. Preliminary analysis of erythroid and granulocytic colonies from one patient with polycythemia vera (PV) and two patients with chronic myelogenous leukemia (CML) indicate that preparations of equal quality are obtained from such individuals and thus, for the first time, the Ph1 chromosome could be readily demonstrated in erythroid colonies. Further application of this method to the investigation of patients with myeloproliferative disease is now underway.

Bone Marrow↗
PubMed1976

Deletion of the short arms of chromosome 20.

A 46, XX, del(20) (p11) karyotype (Paris Conference, 1971) was identified in an 11-month-old French-Canadian girl with a dysmorphic syndrome, multiple congenital anomalies, psychomotor and growth retardation. Both parents had normal phenotype and karyotype.

Chromosome Aberrations↗
PubMed1976

Bilateral renal agenesis with multiple congenital ocular anomalies.

A 920-g male infant born with features of Potter's syndrome had multiple ocular anomalies. Ocular abnormalities included absence of keratocytes in the inner central corneal stroma, cataract with retention of cell nuclei in the nucleus of the lens, hypoplasia of the ganglion cell and nerve fiber layers of the retina, and absence of nerve bundles in the optic nerve. Other ocular findings including microphthalmos, fetal chamber angle, persistent pupillary membrane , retinal avascularity, and prominent Bergmeister's papilla may have been related to the prematurity of the child.

Abnormalities, Multiple↗
PubMedDate not supplied

The early amniocentesis study: a randomized clinical trial of early amniocentesis versus midtrimester amniocentesis.

OBJECTIVES: The primary purpose of this pilot study was to determine whether the safety of early amniocentesis (EA; 11 weeks to 12 weeks and 6 days) is similar to midtrimester amniocentesis (MA; 15 weeks to 16 weeks and 6 days). The secondary objectives were to determine the cytogenetic success and accuracy of EA compared with MA. METHODS: This prospective, randomized clinical trial compared continuous ultrasound-guided EA and MA (22-gauge needle) in patients at a late maternal age (> or = 35 years). The procedures were compared for safety, success and accuracy. RESULTS: Among the 683 women randomized and followed to pregnancy completion, there was a total of 27/344 (7.8%) and 25/339 (7.4%) fetal losses (spontaneous and induced abortions) in the EA and MA groups, respectively (difference 0.4%; CI -3.6 to 4.4%). The rate of postprocedure spontaneous fetal loss was 2.4% (8/330) in the EA group and 3.3% (10/299) in the MA group (NS). The procedure success rate at the first attempt was 97.6% in the EA group and 99.7% in the MA group. There were no diagnostic errors, and all but 2 EA cultures were successful (both repeated successfully). The perinatal outcome was similar in both groups. CONCLUSIONS: EA appears to be as safe and accurate as MA. A large multicentered, randomized trial is currently underway to verify these results.

Amniocentesis↗
PubMedDate not supplied

A co-twin fetus papyraceus as a cause of elevated AFP and acetylcholinesterase in the amniotic fluid of the normal co-twin.

An elevated amniotic fluid alpha-fetoprotein (AF-AFP) level together with a positive acetylcholinesterase (AChE) band is strongly predictive of neural tube defect (NTD) in the fetus. We report such results in a pregnancy in which the fetus was found to be normal after termination. Among the placental fragments was found a sac containing a prenatally undetected co-twin fetus papyraceus. We suggest that pregnant women with such laboratory results but lacking sonographic evidence of NTD should have a high-level untrasonographic investigation, as well as a thorough pathologic examination of both placenta and fetus in cases of termination.

Acetylcholinesterase↗
PubMedDate not supplied

Confined placental mosaicism and stillbirth.

The cause of stillbirth can usually be determined in only 20% of cases. An increased frequency of adverse pregnancy outcome, including pregnancy loss, intrauterine growth restriction, and premature labor, has been observed in association with confined placental mosaicism (CPM), which is characterized by a discrepancy between the karyotype of the fetus and placenta. Specific chromosomal trisomies have been observed in CPM more frequently than others, with trisomy of chromosomes 7, 16, and 18 being the most prevalent. In pregnancies with CPM it has been shown that the zygote is often trisomic, and postzygotic loss of the additional chromosome occurred in the embryonic progenitor cells leading to a dichotomy between the placenta and the embryo/fetus. In one third of such cases fetal uniparental disomy (UPD), which is the presence of both homologues of a chromosome derived from one parent, can be expected. The specific role of the trisomic placenta and the presence of fetal UPD in cases of altered intrauterine fetal development has not been fully established for various chromosomes. Therefore, to enhance our understanding of the pathogenesis of stillbirth it is imperative that cytogenetic analysis of both fetal and placental tissues be performed in all cases of unexplained stillbirth.

Aneuploidy↗
PubMedDate not supplied

Duplication of 9P and hyperplasia of the choroid plexus: a pathologic, radiologic, and molecular cytogenetics study.

Duplication of the short arm of chromosome 9 is a rare constitutional abnormality, and the presence of pathologically confirmed hyperplasia of the choroid plexus in one of two cases, and a choroid plexus papilloma in another, raises the possibility of a relationship between the 9p abnormality and abnormal growth of the choroid plexus. Molecular cytogenetic analysis using fluorescence in situ hybridization was used for detection of chromosome 9-derived material in various formalin-fixed choroid plexus abnormalities. Extra copies of chromosome 9-derived material was found in the hyperplastic choroid plexus and in a choroid plexus carcinoma. These findings suggest that there may be an association between duplication of chromosome 9 material and abnormal development of the choroid plexus.

Carcinoma↗