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Using the G-banding technique, we examined lymphocytes from 90 individuals (43 males and 47 females, median age 31 years) living in buildings constructed with radioactively contaminated rebars. Forty-five nonexposed control subjects (22 males and 23 females, median age 30 years), matched to the radiation-exposed individuals by sex and age, were selected for comparison. At least 500 metaphases were checked for each individual. All recognizable structural aberrations of chromosomes or chromatids were recorded. After adjusting for age and smoking status, both the percentage of cells with aberrant chromosomes (PCAC) and the number of aberrant chromosomes per 100 cells (NAC) were found to be significantly higher in the radiation-exposed females than in the control females (p0.05 for PCAC and NAC). This difference, however, was not observed in the comparison of radiation-exposed and control males. This suggests a possible interaction between sex and radiation exposure in their effects on chromosome aberrations.

Schizophrenia is a common complex mental disorder. The lifetime prevalence of this disease is about 1% across different populations. The etiology is still unknown despite decades of intensive study. This report is aimed at studying the relationship between chromosomal fragile sites and the etiology of schizophrenia. Lymphocytes of 72 schizophrenic patients and 66 healthy controls were cultured in M medium, which is deficient in folic acid, and in medium RPMI1640 with distamycin A. G-banding was carried out on 100 metaphases of each individual. Fragile sites were characterized as specific chromosomal bands that exhibit nonrandom gaps or breaks. Culture in M medium resulted in significant differences in the total number of chromosomal lesions and the total number of cells with chromosomal lesions between patients and controls (P

Fragile X syndrome is a genetic disorder caused by abnormal function of the FMR-1 gene. The majority of fragile X syndrome patients carry an expansion of the CGG tri-nucleotide repeat in the FMR-1 gene, whereas others have a deletion or a point mutation in the FMR-1 structural gene. In this report, we analyzed a typical family with three male patients. RNA from Epstein-Barr virus transformed lymphoblastoid cells was used for RNase protection assay and reverse transcription-polymerase chain reaction (RT-PCR) analysis. Five normal individuals and one asymptomatic heterozygote from this family expressed detectable FMR-1 transcripts, whereas three fragile X patients showed no sign of expression with either assay. To extend the application of this PCR-based assay to laboratory diagnosis of fragile X syndrome, we confirmed that dried blood samples collected on screening filter papers for newborns are an adequate source of RNA for RT-PCR. Moreover, fragile X patients from the study family and another family were reliably identified by the absence of the FMR-1-specific PCR product from the dried blood specimens. Our studies indicate that this simple assay can be used to diagnose the fragile X syndrome for the majority of male patients.

560 blood samples collected from mentally retarded children in Taipei were karyotypically analyzed for the incidence of fragile X and other chromosome abnormalities. The fragile site at Xq27.3 was observed in 18 patients (3.21%), 11 males and 7 females, out of the 560 blood cultures using M medium. Down syndrome (6.25%), 24 males and 11 females, was the other major category of abnormality. Other abnormalities, including inversion, translocation, deletion, duplication, ring as well as an extra marker chromosome were observed. The overall incidence of chromosomal abnormalities in these children was 14.82%. Copyright 1994 S. Karger AG, Basel

The silver staining technique was applied to study the nucleolar organizer regions (NORs) of 38 parents of children with Down syndrome and 40 parents of healthy offspring. Double NOR (dNOR) variants were found in both groups of parents. We compared the incidence of dNOR between these two groups. Our results indicate that different conclusions can be drawn from the same data depending on how the analyses are carried out. It seems to us that dNOR is not a useful marker for predicting whether or not its carrier is at a higher risk of having children with Down syndrome.

Governmental officials as well as medical scientists in Taiwan have worked hard in recent years to develop and to implement various measures, such as prenatal diagnosis and neonatal screening, to lower the incidence of hereditary diseases and mental retardation in the population. An inquiry into the possibility of devising a chromosomal and biochemical screening program and to apply it routinely to all the mentally retarded school children island-wide was the major aim of the present study. A collection of 1,614 blood samples was screened for phenylketonuria (PKU), galactosemia, homocystinuria, biotinidase deficiency, and congenital hypothyroidism. The IQ of these children ranged from 50–75 (1,397 children, moderate group) to less than 50 (217 children, severe group). Six cases of PKU (one tetrahydrobiopterin deficient and five classical) and three cases of thyroid dysfunction were found. The overall incidence of these two diseases was 0.56%. Of the 1,614 blood samples, 1,323 were cultured and karyotyped successfully. One hundred and twenty-five of them had chromosome abnormalities. The majority (64 out of 125) were trisomy 21. A remarkable diffrence in the percentage of mentally retarded children with chromosome abnormalities was observed between the moderate (7.87%) and severe (17.51%) retardates.

The karyotype of an established human hepatoma cell line HA22T/VGH was characterized by G-banding. A majority of the 200 cells counted had around 70 chromosomes at passage 24, and 60 at passage 338. Of the 50 cells karyotyped from each of passage 24 and passages 338-339, chromosomes #13 and #18 were absent. The presence of the Y chromosome was reduced dramatically from a mean value of 1.12/cell at passage 24 to 0.12/cell at passages 338-339. In general, most of the chromosomes--particularly chromosomes #5, #7, #9, #15, and #21--tended to be less represented in the course of propagation in vitro. The presence of multiple copies of a normal chromosome in a single cell was quite common for chromosomes #5 and #7 at both early and late passages. Numerous structural rearrangements of the chromosomes were observed.

The cell line CE48T/VGH was established from an epidermoid carcinoma of the middle third of the esophagus of a 58-year-old male patient. Cytogenetic analysis at passages 90-99 showed that the line was hypotetraploid, with a mean chromosome number of 73. None of the 50 karyotyped cells had a normal chromosome #1 or Y. Cells with multiple copies of some of the autosomes were observed frequently. Structural rearrangements were numerous, especially of chromosomes #1, #9, #14, X, and Y.

Tryptic peptides characteristic of mouse hemoglobin α- and diffuse-type β-chains were isolated from dimethylsulfoxide-treated mouse leukemia virus-infected cell cultures. Quantitative estimates of in vitro hemoglobin synthesis by such cultures were obtained by two different methods: by analysis of radioactive amino acid incorporation, and by single-cell radial immunodiffusion assay. The amounts produced, approximately 4 pg/cell/17 hr, reflect a synthetic capacity that is probably sufficient for 32P labeling of hemoglobin messenger RNAs (mRNA) in quantities commensurate with structural characterization of mRNAs by radioautographic methods.

A gene affecting the final two enzymes of uridylic acid biosynthesis does not affect a third, metabolically adjacent enzyme. Similarly, compounds that increase cellular activity for the affected enzymes do not increase activity for the third enzyme. The pyrimidine pathway can be subdivided into groups of concurrently responding enzymes. These groups may be smaller in human cells than they are in microbial cells.

Mature, circulating mammalian erythrocytes lack dihydroorotic acid dehydrogenase activity. However, we have detected activity, which appears to reside in an enzyme, in malaria parasites purified from mammalian blood.

For the purpose of exploring the possibility of implementing a nation-wide screening program for inherited metabolic diseases and congenital hypothyroidism in Chinese newborn infants, a pilot study was initiated in 1983 to detect patients with phenylketonuria (PKU), galactosemia, homocystinuria, maple syrup urine disease and congenital hypothyroidism (CHT) in mildly mentally retarded (mostly IQ 50–75) school children in Taiwan. Of 4,744 blood samples collected on filter paper from 246 primary and junior high schools all over the island, preliminary screening disclosed six suspected positive cases of PKU and nine of CHT. Two cases of classical PKU, one case of atypical PKU caused by tetrahydrobiopterin deficiency, and seven cases of CHT (one hypoplastic, two athyroid, three ectopic and one dyshormonogenesis) were finally confirmed. In addition to the seven cases of CHT, one more case found by questionnaire survey. This case was missed from the screening because he was recognized as CHT previously and was on thyroxine replacement therapy during screening. The incidence is 1/1, 581 for PKU and 1/593 for CHT in these children.

A 16-year-old boy with classical phenylketonuria (PKU) and mild mental retardation (IQ 69) was detected by the screening of mentally retarded school children in Taiwan with Guthrie's bacterial inhibition assay. The follow-up family study showed that one of his married elder sisters suffered from borderline mental retardation (IQ 75) and was also diagnosed as a classical case of PKU. She had borne one boy and one girl, both suffering from mild mental retardation, microcephaly, delay in linguistic development and severe growth retardation. This is the first known Chinese family with maternal PKU. To prevent future mental retardation caused by maternal PKU, the simultaneous establishment of a register system with a neonatal screening programme, is indicated for the follow-up of PKU girls, screening of the whole family of newly discovered PKU cases, and to exclude unrecognized maternal PKU in women who have given birth to a microcephalic child.

Three epithelial cell lines, CE-48T/VGH, CE-69T/-VGH, and CE-81T/VGH, were established from human squamous cell carcinoma of the esophagus. The cells were polygonal with a high nucleus-to-cytoplasm ratio. Many cells were multinucleate. Electron microscopy revealed the presence of tonofilaments and desmosomes. Chromosome analysis showed that these 3 cell lines were heteroploids of human origin. When transplanted into BALB/c (nu/nu) mice, CE-69T/VGH and CE-81T/VGH produced tumors, the histology of which proved to be carcinomas. All 3 cell lines secreted carcinoembryonic antigen. However, the secretion patterns were different. These 3 cell lines may provide useful models for the study of human esophageal cancer.