Dinucleotide repeat polymorphism at the GABAA receptor beta 3 (GABRB3) locus in the Angelman/Prader-Willi region (AS/PWS) of chromosome 15.
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Biomedical subjects
Publications and source records attributed to A Kuwano.
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Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are distinct mental retardation disorders associated with deletions of proximal 15q (q11-q13) of different parental origin. Yeast artificial chromosome (YAC) clones were isolated for 9 previously mapped DNA probes from this region, and for one newly derived marker, LS6-1 (D15S113). A YAC contig of 1-1.5 Mb encompassing four markers (ML34, IR4-3R, PW71, and TD189-1) was constructed. Multi-color fluorescence in situ hybridization (FISH) analysis of interphase nuclei was combined with YAC contig information to provide the following order of markers: cen-IR39-ML34-IR4-3R-PW71-TD189-1-LS6++ +-1-TD3-21-GABRB3-IR10-1-CMW1-tel. FISH analysis was performed on 8 cases of PWS and 3 cases of AS, including 5 patients with normal karyotypes. All eleven patients were deleted for YACs in the interval from IR4-3R to GABRB3. On the proximal side of the deletion interval, 10/10 breakpoints fell within a single ML34 YAC of 370 kb. On the distal side, 8/9 breakpoints fell within a single IR10-1 YAC of 200 kb. These results indicate a striking consistency in the location of the proximal and distal breakpoints in PWS and AS patients. FISH analysis on a previously reported case of familial AS confirmed a submicroscopic deletion including YACs corresponding to LS6-1, TD3-21 and GABRB3 and supports the separation of the PWS and AS critical regions. Since these three YACs do not overlap each other, the minimum size of the AS critical region is > or = 650 kb.
The inhibitory effect of sulfamonomethoxine and other sulfonamides on the capsule formation of sulfonamide-resistant Bordetella bronchiseptica was investigated. All the sulfonamides having MeO(-OCH3) groups inhibited the capsule formation of B. bronchiseptica. Strong inhibition was obtained with sulfamonomethoxine. Inhibition was not seen with sulfonamides having no MeO groups.
Lissencephaly (agyria-pachygyria) is a brain malformation manifested by a smooth cerebral surface, resulting from arrest of neuronal migration at 10-14 wk gestation. Type I, or classical, lissencephaly can occur either in association with the Miller-Dieker syndrome (MDS) or as an isolated finding, termed "isolated lissencephaly sequence" (ILS). About 90% of MDS patients have visible or submicroscopic deletions of 17p13.3. We therefore investigated the possibility that some ILS patients have smaller deletions in this chromosomal region. Forty-five ILS patients with gyral abnormalities ranging from complete agyria to mixed agyria/pachygyria and complete pachygyria were studied. RFLP analysis with five polymorphic loci in 17p13.3 was performed on all patients and their parents. Somatic cell hybrids were constructed on three patients, to confirm a deletion or to determine the boundaries of a deletion. In-situ hybridization using cosmid probes from within a newly defined lissencephaly critical region was performed on 31 patients as a further method of deletion detection. Six submicroscopic deletions were detected (13.3%). Three of the deletions among 45 ILS patients were detected by RFLP analysis, 4 deletions in 31 patients were detected by in situ hybridization, and one deletion was detected only by somatic cell hybrid studies (in situ hybridization was not performed). Overall, in situ hybridization proved to be the most rapid and sensitive method of deletion detection. The centromeric boundary of these deletions overlapped that of MDS patients, while the telomeric boundary for four ILS deletions was proximal to that of MDS and narrows the critical region for a lissencephaly locus.(ABSTRACT TRUNCATED AT 250 WORDS)
Bordetella bronchiseptica phase I organism possesses a capsule and has the ability to agglutinate with K antiserum, although phase III organism lacks both. The present study examines the effect of sulfamonomethoxine (SMMX) on capsule formation of B. bronchiseptica. I also investigated whether or not the organisms possessed a capsule by bacterial agglutination with K antiserum. Three SMMX-resistant strains of B. bronchiseptica phase I organisms showed loss of agglutinability with K antiserum by culturing them at a higher concentration of 1.56 micrograms/ml of SMMX. These results indicated that capsule formation of SMMX-resistant B. bronchiseptica is inhibited by SMMX.
High-resolution banded chromosomes were obtained in Epstein-Barr virus-transformed lymphoblastoid cells and cultured skin fibroblasts by aphidicolin synchronization, followed by inhibition of chromosome condensation by ethidium bromide. With this method, the chromosomes of 33.3% of lymphoblastoid cells and 48.7% of skin fibroblasts were high-resolution banded, and their mitotic indices were 1.5 and 2.7 times higher than those of control cultures.
To clarify the correlation of cytokine level with the severity and prognosis of children with the hemophagocytic syndrome, we analyzed serum interleukin-1 (IL-1) and tumor necrosis factor (TNF) levels in 26 children with either the virus-associated hemophagocytic syndrome (VAHS, n = 12) or malignant histiocytosis (MH, n = 14). When compared to healthy controls, 13 children had an elevated IL-1 (greater than or equal to 20 pg/ml) and 21 children had an elevated TNF (greater than or equal to 10 pg/ml) level at diagnosis. There was however, no significant difference in the frequency of these high levels between the patients with VAHS and MH. Neither IL-1 nor TNF levels correlated with other clinical or laboratory findings in either VAHS or MH. Two of the 12 patients with VAHS died of an intracranial hemorrhage and 7 of the 14 patients with MH died despite chemotherapy. The MH patients who had a high TNF level (greater than or equal to 50 pg/ml) had a poorer prognosis than those with a low TNF level (less than 50 pg/ml; p less than 0.01). In MH patients, other parameters, such as coagulopathy and lactic dehydrogenase, ferritin and IL-1 levels, did not correlate with prognosis. In 3 patients (2 with VAHS and 1 with MH) analyzed periodically, the change in TNF level was closely associated with the clinical progression or regression of the diseases. Serum cytokine levels may thus be monitored not only for predicting the severity and prognosis of VAHS or MH but also for determining the indications for or timing of chemotherapy. Moreover, TNF may play an important role in the progression of VAHS and MH.
Fluorescence in situ hybridization (FISH) using two cosmid probes (41A and P13) from the Miller-Dieker syndrome (MDS) critical region in 17p13.3 was performed in a blinded comparison of three MDS patients with submicroscopic deletions and in four normal relatives used as controls. The controls showed both chromosome 17 homologues labeled in 85%-95% of cells, while each patient showed only one homologue labeled in 75%-80% of cells. Two MDS patients with cryptic translocations were also studied. In one case, a patient and her mother had the same der(17) (p+), but the reciprocal product of the translocation could not be identified in the mother by G-banding (i.e., it was a "half-cryptic" translocation). FISH revealed a 3q;17p translocation. The other case involved a patient with apparently normal karyotype. Because a large molecular deletion was found, a translocation involving two G-negative telomeres (i.e., a "full-cryptic" translocation) was postulated. FISH studies on her father and normal brother showed an 8q;17p translocation. These studies demonstrate that in situ hybridization is an efficient method for deletion detection in Miller-Dieker syndrome. More important, parental studies by FISH on patients demonstrating molecular deletions and a normal karyotype may identify cryptic translocation events, which cannot be detected by other molecular genetic strategies. Similar in situ strategies for deletion detection can be developed for other microdeletion syndromes, such as Prader-Willi/Angelman syndrome or DiGeorge syndrome.
We studied the clinical significance of genomic amplification of N-myc in Stage IV-S neuroblastoma, with reference to spontaneous regression. Among 103 neuroblastomas in which N-myc was measured, ten were Stage IV-S (eight children were younger than and two were older than 1 year of age). The number of copies of N-myc was 1 to 3 in five patients, four to ten in one patient, and more than ten in four patients, and the survivors of each group were four, one, and one (recurrent), respectively. Of 41 patients younger than 1 year of age, N-myc amplification of more than three copies was found only in Stage IV-S neuroblastoma. Cure with a tendency to regress spontaneously was seen in five of eight patients younger than 1 year of age. However, two patients older than 1 year of age classified as Stage IV-S (one with N-myc amplification) died of progressive disease. In two patients (1 and 3 months of age) with a huge hepatic involvement and in whom the tumor had an amplified N-myc of more than ten copies, tumor regression occurred but there was a relapse to a progressive state later. The overexpression of N-myc mRNA occurred in nine of ten stage IV-S tumors and did not correlate with the prognosis. The vanillylmandelic acid (VMA) to homovanillic acid (HVA) ratio was low in tumors with an increased number of copies of N-myc. Serum lactate dehydrogenase (LDH) levels were increased in Stage IV-S patients with N-myc amplification but not in those with regressing tumors and without N-myc amplification. These data suggest that N-myc amplification may affect the final outcome in the patient classified as Stage IV-S, but tumor regression can occur early after birth and appears to be independent of N-myc amplification.
Common fragile sites were induced by excess thymidine in phytohemagglutinin-stimulated T lymphocytes from 4 normal individuals, and skin fibroblasts from 4 normal and 5 fra(X) positive individuals. The results indicate that the frequency and distribution of excess thymidine-induced fragile sites are different between these two types of cells. The sites at 1p13 and 2p11.2, induced in both types of cells, have not previously been described, and are thus considered to be excess thymidine-specific fragile sites. These findings extend and support our previous studies on cell type-dependent difference in aphidicolin-induced common fragile sites.
The replication status of the fragile X chromosomes was studied in short-term cultures of lymphocytes from six female heterozygous carriers. The fragile X was induced by adding 0.1 microM fluorodeoxyuridine during the last 24 h of culturing. The replication status of the X chromosomes was studied using a bromodeoxyuridine (BrdUrd) antibody method. BrdUrd was added (1) at a final concentration of 0.2 micrograms/ml during the early S phase of chromosome replication (16-10 h before harvest), (2) at 0.2 microgram/ml during the late S phase (the last 6 h of culturing), (3) at 20 micrograms/ml during the early S phase, and (4) at 20 micrograms/ml during the late S phase. BrdUrd that was incorporated into replicating chromosomes was detected by using a nuclease and BrdUrd monoclonal antibody. The frequency of the fragile X was reduced by BrdUrd treatment. The degree of reduction was more severe in the 20 micrograms/ml than in the 0.2 microgram/ml series and was more severe with late S than with early S treatment. Of the early- and late-replicating fragile X chromosomes, those which were actively replicating during a BrdUrd treatment were more reduced than the others. Thus, the average rate of early and late S treatment with 0.2 microgram BrdUrd/ml was assumed to be the closest reflection of the situation in vivo. There was no correlation between the average rate of the early replicating, active fragile X and the intelligence of the heterozygous carriers studied.
The distribution and frequency of aphidicolin-induced common fragile sites were studied in Epstein-Barr virus-transformed B lymphocytes from eight normal individuals, and in bone marrow cells from six children in remission from malignant blood diseases. PHA-stimulated helper T lymphocytes from the same individuals were also studied. These cells were cultured in MEM, and treated with 0.2 microM aphidicolin for 26 h. The results, together with those of our previous study on cultured skin fibroblasts, indicated that the distribution and frequency of aphidicolin-induced fragile sites are different among different types of cells.
The distribution and frequency of aphidicolin-induced common fragile sites were studied in chromosomes of cultured skin fibroblasts and PHA-stimulated lymphocytes from five normal individuals; 0.2 microM aphidicolin was added for the last 26 h of culture. Skin fibroblasts from five fra(X)-positive patients were also studied in the same manner. Fragile sites most frequently found in fibroblasts from normal individuals were 3q26.2, 7q11.23, 16q23, 1p31, 10q11.2, 12q23 and 7q31, whereas those in lymphocytes from the same individuals were 3p14, 16q23, Xp22, 7q32 and 14q24. The distribution of fragile sites in fibroblasts from fra(X)-positive patients was essentially identical with that in normal individuals. The average number of gaps and breaks in 100 metaphases was 36.8 in fibroblasts from normal individuals, 113.8 in those from fra(X)-positive patients, and 279 in lymphocytes from normal individuals. Their rates of chromosome-type breaks and gaps were 7.9%, 29.7% and 54.5%, respectively. Thus, the distribution and frequency of aphidicolin-induced fragile sites were different between skin fibroblasts and lymphocytes, possibly reflecting differences in their DNA replication sequence or gene activity.
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Of 10 patients with typical Sotos sequence, 5 had various congenital heart defects. They included 2 patients with secundum atrial septal defect, and one patient each with patent ductus arteriosus with mitral valve regurgitation, tricuspid atresia plus pulmonary atresia, and ventricular septal defect. Increases of head circumference and weight gain were less accelerated in the patients with congenital heart defects than in those without heart defects, while growth in length was comparable between the 2 groups. In view of these findings, it is suggested that the rate of congenital heart defects in patients with Sotos sequence is much higher than that reported in the literature.
The effect of ethanol on the frequency of aphidicolin-induced common fragile sites was studied using lymphocyte cultures from two normal women. Aphidicolin was added to the cultures at a final concentration of 0.2 microM and ethanol at 0.02%, 0.1%, 0.2%, 0.5%, and 1%, both during the last 26 h of culture. The frequency of common fragile sites increased from 296% in subject 1 and 201% in subject 2 with aphidicolin plus 0.02% ethanol, to 765% and 823%, respectively, with aphidicolin plus 1% ethanol. Ethanol alone added to cultures did not induce common fragile sites. The gaps and breaks induced by aphidicolin plus ethanol were highly nonrandom. Altogether, 35 common fragile sites were identified. The addition of 1% ethanol to aphidicolin increased both random and nonrandom gaps and breaks as compared with that of 0.02% ethanol. Dimethyl sulfoxide added to culture at final concentrations of 0.02% to 1% did not change the frequency of aphidicolin-induced fragile sites. The frequency of fluorodeoxyuridine-induced fragile sites was not affected by the addition of 0.02% to 1% ethanol. It was thus concluded that ethanol enhances the aphidicolin-induced fragile sites, possibly inhibiting the repair mechanism of gaps and breaks induced by aphidicolin.
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