Karyotype-phenotype correlation in partial trisomies of the short arm of chromosome 6: a family case report and review of the literature.

The first child (proband) of nonconsanguineous Caucasian parents underwent genetic investigation because she was affected with congenital choanal atresia, heart defects and kidney hyposplasia with mild transient renal insufficiency. The direct DNA sequencing after PCR of the CHD7 gene, which is thought to be responsible for approximately 60-70% of the cases of CHARGE syndrome/association, found no mutations. The cytogenetic analysis (standard GTG banding karyotype) revealed the presence of extrachromosomal material on 10q. The chromosome analysis was completed with array CGH (30 kb resolution), MLPA and FISH, which allowed the identification of three 6p regions (6p.25.3p23 × 3): 2 of these regions are normally located on chromosome 6, and the third region is translocated to the long arm of chromosome 10. The same chromosomal rearrangement was subsequently found in the father, who was affected with congenital ptosis and progressive hearing loss, and in the proband's sister, the second child, who presented at birth with choanal atresia and congenital heart defects. The mutated karyotypes, which were directly inherited, are thought to be responsible for a variable phenotype, including craniofacial dysmorphisms, choanal atresia, congenital ptosis, sensorineural hearing loss, heart defects, developmental delay, and renal dysfunction. Nevertheless, to achieve a complete audiological assessment of the father, he underwent further investigation that revealed an increased level of the coagulation factor XIII (300% increased activity), fluctuating levels of fibrin D-dimer degradation products (from 296 to 1,587 ng/ml) and a homoplasmic mitochondrial DNA mutation: T961G in the MTRNR1 (12S rRNA) gene. He was made a candidate for cochlear implantation. Preoperative high-resolution computed tomography and magnetic resonance imaging of the temporal bone revealed the presence of an Arnold-Chiari malformation type I. To the best of our knowledge, this study is the second report on partial 6p trisomy that involves the 10q terminal region. Furthermore, we report the first case of documented Arnold-Chiari malformation type I and increased factor XIII activity associated with 6p trisomy. We present a comprehensive report of the familial cases and an exhaustive literature review.

Short-term treatment for adult hypergranular and microgranular acute promyelocytic leukemia.

A high hemorrhagic risk and a complete response to the differentiative agent all-trans-retinoic acid (ATRA) are the main clinical features of acute promyelocytic leukemia (APL), two distinct subtypes of which have been recognized, the common hypergranular leukopenic form (M3) and a microgranular hyperleukocytic variant (M3v). We analyzed, with emphasis on both disease- and therapy-related prognostic factors, the results from a 9-year trial in 65 adults with M3 and M3v APL, treated homogenously with a short-term therapy (STT) program excluding maintenance. STT comprised a maximum of six courses with doxorubicin, cytosine arabinoside (ara-C), and 6-thioguanine. Sixty-five APL patients formed the study group, M3v accounting for 25% of cases. In M3v, the absolute blast cell count was significantly higher (p < 0.0001) and early hemorrhagic deaths were more frequent (p = 0.05). The blast count correlated inversely with the probability of remission (p = 0.005), poor-risk patients being those with > 10 x 10(9)/l blast cells. During the study, the median survival improved from 0.1 to 2.7 years (p = < 0.005). In first place, response to chemotherapy increased from 42 to 84% (p = 0.006), by giving daily prophylactic platelet transfusions (to > 30 x 10(9)/l) and no heparin (course I), and by avoiding too toxic high-dose ara-C and deferring treatment in infected/neutropenic patients showing the atypical differentiative bone marrow pattern (course II). Secondly, the probability of first unmaintained remission differed significantly between patients given intentionally more than four total chemotherapy courses or intermediate/high-dose ara-C consolidation (0.59 at 5 years) and those treated less intensively (0.21) (p < 0.005). Intensive STT was very effective for the management of adult APL patients at standard hemorrhagic risk and receiving optimal supportive care. In high-risk patients with hyperleukocytosis and M3v, induction results could be improved by the concomitant use of ATRA. M3v in adults must be recognized promptly because of the very high early hemorrhagic risk.

Evaluation of the toxic activity of anorectic diethylpropion in Chinese hamster ovary cells.

Diethylpropion has been available in the market for treating obesity for over 50 years. Refined studies are lacking to fully elucidate its action spectrum. The aim of our study was to evaluate possible toxic effects of anorectic diethylpropion in Chinese hamster ovary (CHO) cells. Comet assay (detects breaks in the DNA strand), micronucleus test (detects clastogenic/aneugenic damage), and cell survival test (detects cytotoxic damage) were used to evaluate the toxic effects. In comet assay, we found that the damage scores with diethylpropion treatments at the concentrations of 20 and 40 µg/mL were more significant ( p < 0.05) than that of the negative control. When assessing the possible aneugenic and/or clastogenic damage caused by the drug in CHO cells, we found no difference ( p > 0.05) in the values of micronucleated cells when comparing different diethylpropion treatments and the negative control. Regarding the cell viability, for all the diethylpropion concentrations tested, higher values ( p < 0.05) of apoptosis were found compared with those of the negative control. In relation to the number of necrotic cells, no difference ( p > 0.05) was noted between the means of the three concentrations of diethylpropion evaluated and the negative control. In the experimental conditions, we conclude that diethylpropion has weak genotoxic and cytotoxic activities.

Large-cell medulloblastomas. A distinct variant with highly aggressive behavior.

We present four cases of infantile cerebellar neoplasms composed of cells with large vesicular nuclei with prominent nucleoli. All four cases were strongly immunoreactive for synaptophysin, and one case showed immunoreactivity for neurofilaments. Filter hybridization for N-myc and c-myc oncogenes showed a 27-fold c-myc amplification in one case. The cytogenetic analysis in this case showed Double-Minutes and isochromosome 17q. An intracerebral xenograft in nude mice obtained from one such tumor showed a similar morphology to that of the original tumor as well as strong immunoreactivity for synaptophysin and neurofilaments. All the neoplasms were characterized by highly aggressive behavior leading to early cerebrospinal fluid dissemination despite radiotherapy and chemotherapy. We conclude that large-cell medulloblastoma represents a distinct and more aggressive variant of medulloblastoma that requires more aggressive therapy.

Nonrandom gain of chromosome 7 in central neurocytoma: a chromosomal analysis and fluorescence in situ hybridization study.

Central neurocytoma is a benign, slow-growing neoplasm with favourable prognosis. Biomolecular analysis has failed to demonstrate significant alterations, and no cytogenetic alterations have been reported. In this study we demonstrate chromosome 7 gain in three of nine neurocytomas (33%). Traditional cytogenetic analysis performed in four of the nine cases identified trisomy 7 as the sole chromosomal abnormality in one case. Interphase cytogenetics utilizing fluorescent in situ hybridization (FISH) on cell suspensions from formalin-fixed paraffin-embedded tumour tissue performed in all nine cases detected trisomy 7 in two more cases and tetrasomy in another. Our results suggest that chromosome 7 gain is a feature of neuroectodermal tumorigenesis, possibly conferring growth advantage on the neoplastic cells. FISH on interphase nuclei is a valuable adjunct in the genetic evaluation of rare central nervous system neoplasms with low baseline proliferative activity.

A mesenchymal chondrosarcoma of a child with the reciprocal translocation (11;22)(q24;q12).

The reciprocal translocation (11;22)(q24;q12) was observed in a seven day culture from a mesenchymal chondrosarcoma of the bone, a tumor not characterized cytogenetically so far. We suggest that because of the presence of a similar cytogenetic abnormality, mesenchymal chondrosarcoma may belong to the wide group of "t(11;22)-small round cell tumors".

Recurrent chromosomal aberrations in peripheral T-cell lymphoma.

Histological, immunological, and cytogenetic analysis of the same neoplastic tissues have been performed on seven patients with peripheral T-cell lymphomas (PTCL). Clonal chromosomal abnormalities in five cases are reported. The most common chromosomal aberration, observed in four patients, is a rearrangement of chromosome 14 with a breakpoint in q11.2. Aberrations of chromosome 8 also occurred in four patients, three of whom had an extra 8q. The data indicate that breakpoints of malignant diseases affecting similar cell types might cluster to specific chromosomal regions, which can be helpful in recognition and classification of PTCL.

Cytogenetic and clinical studies in acute promyelocytic leukemia (M3) and cytologic M3 variant (M3V).

Cytogenetic specimens were obtained from bone marrow 24-hour cultured cells in 22 patients with acute promyelocytic leukemia, including six with microgranular variant. A t(15;17) was identified in 10-100% of metaphase cells from 13 patients. We have found no correlation between complete remission percentage and karyotype. Our data suggest that each laboratory, as far as M3 and M3V are concerned, must study its own culture time as it relates to numerous parameters involving tumoral cell kinetics.

Cytogenetics of pediatric central nervous system tumors.

A cytogenetic analysis was performed on short-term cultures of 43 previously untreated childhood central nervous system neoplasms of various histology. The cells were obtained from pediatric patients, none of whom had received therapy before karyotypic evaluation. Successful chromosome studies were performed on 24 tumors. The most commonly detected structural abnormalities involved chromosomes 1 and 17. Other structural chromosome abnormalities involved chromosomes 3, 6, 8, 9, 11, 12, and 20.

Cytogenetic analysis of hepatoblastoma: hypothesis of cytogenetic evolution in such tumors and results of a multicentric study.

Hepatoblastoma is a rare pediatric malignant tumor of the liver. Previous cytogenetic reports are sporadic. We karyotyped nine consecutive hepatoblastomas from the Italian centers participating in a multicentric study on hepatic tumors (SIOPEL 1). Six cases showed abnormal karyotypes. The most common abnormalities were trisomies of chromosomes 2 and 20. Four cases showed abnormalities of chromosome 1. On the basis of findings, we speculate the possibility of a cytogenetic evolutive pattern of hepatoblastomas.

Cytogenetic t(11;17)(q13;q21) in a pediatric ependymoma. Is 11q13 a recurring breakpoint in ependymomas?

Cytogenetic studies on a supratentorial ependymoma from a 1-year-old boy showed a t(11;17)(q13;q21). This is the second ependymoma reported with a rearrangement at 11q13; to our knowledge the 11q13 is the first recurring breakpoint reported in ependymoma.

Trivalent chromium is neither cytotoxic nor mutagenic in permeabilized hamster fibroblasts.

BHK cells became reversibly permeable by a 30-min incubation in hypertonic medium. During permeabilization they were exposed to water-soluble Cr(VI) (K2Cr2O7) and Cr(III) (CrCl3). Thymidine uptake in the intracellular nucleotide pool, DNA replication, DNA damage and repair and sister-chromatid exchanges (SCE) were examined to detect the cytotoxic and genetic effects of Cr compounds. Cr(III) remained inactive also in permeabilized cells. An apparent induction of DNA damage by Cr(III), suggested by the Painter's test, was considered unreliable. Cr(VI) cytotoxic and genetic activity was enhanced in permeabilized cells, as demonstrated by increased inhibition of DNA replication and higher frequency of SCE.

Nitrilotriacetic acid (NTA) does not induce chromosomal damage in mammalian cells either in vitro or in vivo.

We used human lymphocyte cultures to repeat the experiments under the very particular conditions of nitrilotriacetic acid (NTA) treatments (high doses: up to 10(-2) M; very long exposure times: up to 5 days) which have been described as being able to induce chromosomal aberrations, and we also performed the more conventional treatments (24-48 h of exposure) as suggested in the protocols adopted by the EEC-OECD. Mitomycin C was routinely used as a positive clastogenic control. NTA did not significantly increase the frequency of chromosomal aberrations in any of the different experimental conditions adopted. Furthermore, no induction of micronuclei was observed in mouse polychromatic erythrocytes after treatment in vivo for up to 48 h with NTA (200-400 mg/kg b.w.), whereas the frequency of micronuclei was significantly increased by mitomycin C (1 mg/kg b.w.).

Induction of sister-chromatid exchanges in human lymphocytes exposed in vitro and in vivo to therapeutic ultrasound.

The induction of sister-chromatid exchanges (SCEs), chromosomal aberrations and cell-cycle delay was determined in human lymphocytes after treatment in vitro and in vivo with therapeutic ultrasound (u.s.). In vitro treatments (1 W/cm2; 0.860 MHz; for 40-160 sec) were performed on unstimulated lymphocytes from 9 donors: a statistically significant, dose-dependent increase in SCE frequency was produced, whereas no induction of chromosomal aberrations nor alteration of the distribution of 1st, 2nd and 3rd division metaphases were observed. The same increase in the frequency of SCEs was detected by treating in vitro stimulated lymphocytes with u.s. The effects of in vivo exposure to u.s. were detected on lymphocytes from 10 patients before, during and after u.s. therapy (0.6-1.0 W/cm2; 0.860 MHz; from 8 to 20 applications lasting 5-6 min each). SCE frequency was statistically significantly increased in all patients at mid-therapy, without a further increase during the second half of therapeutic cycle, and was restored to pretreatment level 3 months after the end of u.s. therapy. No increase in chromosomal aberrations was noticed during and after u.s. therapy, whereas erratic delays of the cell cycle were observed, not clearly related to u.s. application or SCE levels. A linear relationship was found between SCE frequency and age in 21 healthy donors.

Effects of nitrilotriacetic acid on the induction of gene mutations and sister-chromatid exchanges by insoluble chromium compounds.

The influence of nitrilotriacetic acid trisodium salt (NTA) on the mutagenic and clastogenic activity of several water-insoluble or poorly soluble chromium compounds was determined by means of the Salmonella/microsome assay (plate test on TA100 strain) and the sister-chromatid exchange (SCE) test in mammalian cell cultures (CHO line). NTA in itself did not induce gene mutations nor did it increase the frequency of SCE. Cr(VI) compounds (Pb, Ba, Zn, Sr and Ca chromates) and an industrial Cr(VI) pigment, chromium orange (containing PbCrO4 PbO), were inactive or scarcely active mutagens in the Salmonella/microsome test when dissolved in water, but they were increasingly mutagenic when solubilized by 0.5 N NaOH or NTA (10 or 100 mg/ml). Also, the mutagenic activity of Cr(VI), contaminating an industrial Cr(III) pigment (chromite), was slightly enhanced by NTA. Mutagenicity of chromates was correlated with the amounts of Cr(VI) solubilized by NTA or alkali, as determined by the colorimetric reaction with diphenylcarbazide and atomic absorption spectrophotometry, and was decreased by incubation with microsomes, due to reduction of Cr(VI) to the genetically inactive Cr(III) form. In the SCE assay, the insoluble or poorly soluble Ba, Zn, Sr and Ca chromates and the insoluble Cr(VI) pigments zinc yellow (containing ZnCrO4 Zn(OH2], chromium yellow and molybdenum orange (both containing PbCrO4) were directly clastogenic due to cellular endocytosis taking place in prolonged treatments, and NTA significantly increased their chromosome-damaging activity.

Genetic effects of chromium compounds.

Seven different test systems were utilized to investigate the genetic activity of chromium compounds: infidelity of DNA replication in vitro by DNA pol alpha from calf thymus, damage of DNA detected by alkaline elution in treated mammalian cells or in DNA purified and treated in vitro, DNA repair synthesis in mammalian cells in vitro detected by autoradiography or scintillation counting after labelling with [3H]dThd, gene mutations in the Salmonella typhimurium Ames test, gene mutations (6TG resistance) in cultured hamster cells, sister-chromatid exchanges in different rodent cell cultures, and transformation to anchorage-independent growth of hamster cells in vitro (soft-agar assay). Potassium dichromate and chromium chloride were used as water-soluble Cr(VI) and Cr(III) salts. Several reference mutagens (EMS, MMS, MMC, 4NQO) were included in the single tests as positive controls. Cr(VI) was active in all the tested systems, except in the induction of DNA damage and DNA repair synthesis in cultured cells. Cr(III), on the other hand, was absolutely inactive unless a direct interaction with purified DNA was permitted by the test conditions. The relevance of data from the various tests to the understanding of the mechanisms of the genotoxic activity of chromium is discussed. Effects other than the direct interaction of Cr(III) with DNA are inferred, which can cause infidelity of the DNA polymerase functions.

Solubilization by nitrilotriacetic acid (NTA) of genetically active Cr(VI) and Pb(II) from insoluble metal compounds.

The frequencies of sister chromatid exchanges (SCE) were significantly increased in cultured Chinese hamster cells by insoluble salts of Cr(VI) (PbCrO4) and Pb(II) (PbSO4). A further significant increase of this effect was produced when diluted suspensions of PbCrO4 (1-4 mg/l) and PbSO4 (10-40 mg/l) were preincubated with nitrilotriacetic acid (NTA) concentrations (0.25-1 mg/l) such as those that are possibly found in highly contaminated environmental situations. NTA enhanced the induction of SCE by PbCrO4 and PbSO4 even in the presence, in the preincubation solution and in the medium used to treat the cells, of Na+ and K+ concentrations largely exceeding (e.g., 10(2)-10(6) times) those of the genotoxic metals.

Cytotoxic, mutagenic and clastogenic effects of industrial chromium compounds.

Ten Cr(III) compounds, used in the leather tanning industry, and a Cr(III) compound, containing chromite and used as a pigment, were tested for cytotoxicity (inhibition of growth and survival of cultured hamster cells), mutagenicity (point mutations in S. typhimurium) and clastogenic activity (chromosomal aberrations and sister chromatid exchanges in hamster cells). Reference Cr compounds were potassium dichromate as Cr(VI), and chromium chloride and two different preparations of chromium nitrate as Cr(III). A contamination with Cr(VI) was detected in some of the Cr(III) tannins, chromite and one chromium nitrate. Cr(III) compounds were cytotoxic at concentrations of Cr(III) 100-500 times higher than Cr(VI), but contaminated Cr(III) compounds showed a significant cytotoxicity. Reference Cr(VI) but not Cr(III) was mutagenic: of the contaminated compounds only chromite and chromium nitrate, which contained higher levels of Cr(VI), were found to be mutagenic. The frequency of sister chromatid exchanges was significantly increased only by Cr(VI) and the more contaminated Cr(III) compounds. However, an increase of chromosomal aberrations was produced also by reference Cr(III) salts and the weakly contaminated industrial Cr(III) compounds. These results confirm the view that the active mutagenic agent in intact cell systems is Cr(VI), but indicate that industrial Cr(III) compounds cannot be considered genetically inert, as they can be contaminated by Cr(VI) and induce chromosomal aberrations.