Evolution of unbalanced gain of distal chromosome 2p in neuroblastoma

Neuroblastoma, one of the most common tumors of childhood, presents at diagnosis with a vast number of recurrent chromosomal imbalances that include hyperdiploidy for whole chromosomes, partial loss of 1p, 3p, 4p, 11q, 14q, partial gain of 1q, 7q, 17q and amplification of MYCN. These abnormalities are nonrandomly distributed in neuroblastoma as loss of 3p and 11q rarely occur in MYCN amplified neuroblastomas. Here, we report on a patient who had a non-MYCN amplified 3p-/11q- neuroblastoma at diagnosis who subsequently developed a high level of MYCN amplification in bone marrow metastases 41 months after induction of complete remission. The tumor at diagnosis had low level unbalanced gain of distal 2p. In order to assess the frequency of low level gain of distal 2p in neuroblastoma, we examined the comparative genomic hybridization results from 60 neuroblastomas. Among non-MYCN amplified neuroblastomas, 8/45 (18%) had low level gain of distal 2p. Low level gain for a segment of 2p (i.e. a region larger than the 2p23-->p24 undergoing amplification) was also detected in five of the 15 tumors that had high level MYCN amplification. The possibility that low level gain of distal 2p is a risk factor for high level MYCN amplification is discussed.

Molecular cytogenetic analysis of recurrent unbalanced t(11;17) in neuroblastoma

Loss of 11q material occurs in approximately 30% of advanced stage neuroblastoma and defines a distinct genetic subtype of this disease. These tumors almost always possess unbalanced gain of the 17q, along with many additional recurrent chromosomal imbalances. Loss of 11q and gain of 17q is often the consequence of an unbalanced translocation between the long arms of both chromosomes, but because of the involvement of other chromosomal mechanisms, the actual frequency of t(11;17) is unknown. In addition, chromosomal breakpoint positions for the t(11;17) are variable in different tumors, with breakpoints on neither the 11q nor 17q being well defined. We have used interphase fluorescence in situ hybridization analysis to detect a der(11)t(11;17) in a series of neuroblastomas with 11q loss/17q gain using a statistical approach which could be applicable to the detection of translocations in other solid tumors. The frequency of der(11)t(11;17) was approximately 90% in our neuroblastoma series. A balanced t(11;17) was also detected in a MYCN amplified tumor, which is a distinctly different genetic subtype from the 11q- tumors. Breakpoint positions on 11q were determined to be variable, whereas all breakpoints on 17q appeared to cluster proximal to position 43.1 Mb on the DNA sequence map. The majority of tumors had large numbers of nuclei with 2 or more copies of der(11)t(11;17), which led to unbalanced gain of 11p, and further increases in 17q imbalance. The prevalence of t(11;17) in neuroblastoma warrants additional studies to further define the range in variation in breakpoint positions on both chromosomes and to elucidate the molecular mechanisms that lead to this important and interesting recurrent genetic abnormality.

Are gains of chromosomal regions 7q and 11p important abnormalities in neuroblastoma?

Neuroblastoma exhibiting deletion of a segment of the long arm of chromosome 11 represents a genetic subtype of tumor that is distinct from those exhibiting MYCN amplification or 1p deletion. The 11q- genetic subtype is further characterized by gain of 17q and loss of distal 3p material. Gain of 11p material has also been reported in neuroblastoma with 11q loss, but at a considerably lower frequency than gain of 17q or loss of the distal 3p region. Our results, however, indicate that gain of 11p may occur more frequently in 11q- neuroblastoma than what was previously realized. Comparative genomic hybridization analyses of neuroblastoma tissue from eleven patients indicated that six of 11 tumors (55%) with loss of 11q also possessed gain of 11p. The shortest region of 11p gain was 11p11.2-->p14. G-banding and fluorescence in situ hybridization analysis performed on tumor cells from primary and metastatic sites from one patient allowed us to infer that gain of 11p arose secondarily to the abnormality that led to the loss of 11q material. Gain of an entire chromosome 7 was detected in 17 of 43 (40%) tumors, whereas gain of 7q was detected in 5 of 43 (12%) tumors. Unlike gain of 11p, gain of an entire chromosome 7 appears to be prevalent in all tumor stages and is not limited to the 11q- tumor subtype. Gain of 7q, however, is more prevalent in higher stage tumors. G-band cytogenetic analysis indicated that an unbalanced t(3;7) was responsible for the gain of 7q and loss of 3p material in one case. We discuss the possibility that gain of 7/7q, and 11p material may contribute to either tumorigenesis or progression.

Genetic abnormalities in a pre and post-chemotherapy hepatoblastoma

Comparative genomic hybridization (CGH) analysis was performed on both a pre- and post-chemotherapy hepatoblastoma from a 24-month-old female patient. The diagnostic sample obtained from a tru-cut biopsy was a mixed epithelial-mesenchymal tumor with both fetal and embryonal patterns present. In contrast, the post-chemotherapy tumor exhibited a prominent anaplastic large cell population focally reminiscent of pleomorphic hepatocellular carcinoma (HCC). CGH analysis indicated that there were similarities as well as differences in the gains and losses of genetic material in each tumor. The diagnostic sample had gains of chromosome 1q, 2, 2(q31q33), 7, 8q, 12(q15q22), 17q and 20 material, while the post-chemotherapy tumor had gains of 1q, 2, 7, 8q, 10, 17q and 20 material. In addition, the pre- and post-chemotherapy samples may have incurred loss of chromosome 17p material. The main differences between the two samples involved localized gain of 2(q31q33) and 12(q15q22) in the pre-chemotherapy sample, and gain of chromosome 10 material in the post-chemotherapy tumor. The patient subsequently developed metastatic nodules in her lungs, the histology of which was identical in pattern to the diagnostic pattern, and appeared to have localized gain of 2(q31q33) and 12(q15q22). These results are consistent with published results that gain of chromosome 8q and 20 are associated with an unfavorable prognosis.

Coordinate deletion of chromosome 3p and 11q in neuroblastoma detected by comparative genomic hybridization

Neuroblastoma, the most common extracranial solid tumor of childhood, is associated with a number of genetic abnormalities that are prognostically significant. The most common abnormalities are associated with aggressive clinical behavior and include deletion of distal chromosome 1p, NMYC amplification, and unbalanced gain of the long arm of chromosome 17. There are also other recurrent, but less frequent abnormalities, the clinical significance of which is uncertain. These less common abnormalities include deletion 3p, 11q, and 14q. To gain further clinical insight into some of the less commonly observed abnormalities in neuroblastoma, we performed comparative genomic hybridization (CGH) analysis on 24 primary and metastatic neuroblastomas (6 stage 2, 5 stage 3, 11 stage 4, and 2 stage 4). Nineteen of these tumors were prechemotherapy. A total of 190 abnormalities were detected from these tumors. Four of the 24 tumors studied showed loss of 11q material, with 3 of these tumors also possessing distal chromosome 3p deletions. Our results provide confirmation that deletion of chromosome 3p is nonrandomly associated with deletion of chromosome 11q in neuroblastoma. However, analysis of our results, along with other results reported in the literature, indicate that there is no statistically significant association between 3p and 11q loss and more clinically aggressive tumors.

Isolation and analysis of thermotolerant mutants of wheat

Thermotolerant mutants of wheat cv. Guardian were isolated by selecting survivors from 5-d-old seedlings of M2 populations exposed to 47 degrees C for 90 min. Progeny testing, using triphenyl tetrazolium chloride reduction as a measure of tissue viability, following heat stress treatment for 120 min at each of three temperatures (32, 38 and 50 degrees C), confirmed the thermotolerant nature of seedlings of 13 mutants. Mutants were isolated at frequencies of 0.1% and 0.2% following the use of sodium azide and ethyl methanesulphonate, respectively. The relative thermotolerance of ten of the mutants and 'Guardian' was then tested by exposing plants to heat stresses of 38 degrees C for 6 h in every 24 h for five successive days at one of four growth stages between seedling and anthesis. Pmax (light-saturated net photosynthetic rate) and chlorophyll content were compared in stressed and unstressed plants. The Pmax of 'Guardian' was depressed by at least 23% by heat stress at each stage; this inhibition was least at ear emergence and greatest at anthesis, the latter being associated with reduced sink size as a result of lowered seed set. The stress-induced inhibition of Pmax in 'Guardian' plants at anthesis had not recovered 3 d after removal of the stress. Mutant lines exhibited different developmental profiles of Pmax thermostability. Mutant tht (thermotolerant) 10, for example, exhibited partial thermostability at each growth stage tested while the Pmax of mutant tht 2 was completely unaffected by heat stress at second node and ear emergence, but was as inhibited as that of 'Guardian' at anthesis; heat stress applied at anthesis in tht 2, but not tht 10, was associated with reduced seed set. Generally, the inhibitory effect of heat stress on Pmax in the mutants was reflected in declines in chlorophyll content. The ten mutants were grouped into nine categories, on the basis of thermotolerance characteristics.

Isolation and analysis of thermotolerant mutants of wheat

Thermotolerant mutants of wheat cv. Guardian were isolated by selecting survivors from 5-d-old seedlings of M2 populations exposed to 47 degrees C for 90 min. Progeny testing, using triphenyl tetrazolium chloride reduction as a measure of tissue viability, following heat stress treatment for 120 min at each of three temperatures (32, 38 and 50 degrees C), confirmed the thermotolerant nature of seedlings of 13 mutants. Mutants were isolated at frequencies of 0.1% and 0.2% following the use of sodium azide and ethyl methanesulphonate, respectively. The relative thermotolerance of ten of the mutants and 'Guardian' was then tested by exposing plants to heat stresses of 38 degrees C for 6 h in every 24 h for five successive days at one of four growth stages between seedling and anthesis. Pmax (light-saturated net photosynthetic rate) and chlorophyll content were compared in stressed and unstressed plants. The Pmax of 'Guardian' was depressed by at least 23% by heat stress at each stage; this inhibition was least at ear emergence and greatest at anthesis, the latter being associated with reduced sink size as a result of lowered seed set. The stress-induced inhibition of Pmax in 'Guardian' plants at anthesis had not recovered 3 d after removal of the stress. Mutant lines exhibited different developmental profiles of Pmax thermostability. Mutant tht (thermotolerant) 10, for example, exhibited partial thermostability at each growth stage tested while the Pmax of mutant tht 2 was completely unaffected by heat stress at second node and ear emergence, but was as inhibited as that of 'Guardian' at anthesis; heat stress applied at anthesis in tht 2, but not tht 10, was associated with reduced seed set. Generally, the inhibitory effect of heat stress on Pmax in the mutants was reflected in declines in chlorophyll content. The ten mutants were grouped into nine categories, on the basis of thermotolerance characteristics.

Chromosome deletion 17p11.2 (Smith-Magenis syndrome) in seven new patients, four of whom had been referred for fragile-X investigation

We report seven new patients with clinical features of the Smith-Magenis syndrome (SMS) and small de novo interstitial deletions of 17p11.2. Four of these patients had been referred for fragile-X studies, but standard G-banded chromosome analysis routinely carried out in addition to the fragility tests revealed the microdeletion in chromosome 17. A relatively high proportion (approximately 2%) of patients referred to this Centre for fragile-X investigation are found to have a chromosome abnormality other than fra(X)(q27.3), half of them (approximately 1%) with an unbalanced chromosome complement. The four of our seven patients with deletion 17p11.2 constitute 25% of those with an unbalanced karyotype, and establish this microdeletion as the most common chromosome abnormality-except for fra(X)(q27.3)-in patients referred for fragile-X screening. The data indicate that standard karyotyping should be offered to patients with this referral indication, in addition to any molecular or chromosome fragility tests for fragile X. We also recommend that the short arm of chromosome 17 be examined critically in these patients. Moderate quality and resolution of banding (450-550 bands per haploid chromosome set) are adequate for detection of the 17p11.2 deletion.

A comparative study of the clinical efficacy of nedocromil sodium and placebo. How does cromolyn sodium compare as an active control treatment?

Nedocromil sodium and cromolyn sodium are the only two currently available nonsteroid anti-inflammatory agents for treatment of asthma. Clinical differences between the two agents remain under continuous investigation with reports differentiating the two on the basis of atopy of the patient and reversibility of bronchoconstriction. This study investigated the efficacy of nedocromil sodium (4 mg, qid) for treatment of mild-to-moderate asthma in comparison to placebo using cromolyn sodium (2 mg, qid) as an active control treatment. Patients were primarily allergic asthmatics (with at least 15% reversibility) previously maintained on a regimen of regular bronchodilator therapy. During a 2-week run-in period, the patient's slow-release theophylline therapy was removed, and the patients were randomized to treatment after deterioration of asthma control (asthma symptom summary score of 3 for 7 of the 14 days). After 8 weeks of treatment, patients were returned to as occasion requires bronchodilator therapy, as per the 2-week baseline period. The results demonstrate that patients treated with nedocromil sodium showed statistically significant improvements during the primary time period (mean weeks 3 through 8) over placebo-treated patients as evidenced by all indexes of asthma symptoms, pulmonary function measures, and decreased bronchodilator reliance (p<0.05). Patients treated with cromolyn sodium demonstrated similar improvements over placebo-treated patients. Comparisons between nedocromil sodium and cromolyn sodium showed the two agents to be comparable in this group of primarily allergic patients with reversible disease. Between-group differences were noted for 3 of the 13 variables (nighttime asthma, FEV1, and forced expiratory flow rate between 25 % and 75% of the FVC) in favor of cromolyn sodium when the data were pooled during the primary time period. The number of patients missing 1 or more days from work/school/regular activity due to asthma was significantly fewer compared with placebo, and favoring nedocromil sodium over cromolyn sodium. No differences were observed among the three treatments for adverse events. This study demonstrated that in primarily allergic patients with reversible airways disease, nedocromil sodium and cromolyn sodium are both significantly more effective than placebo for treatment of mild-to-moderate asthma.

Immunosuppressive therapy for asthma

Over the last four or five years, there have been some serious attempts to look for alternatives to corticosteroids in the management of severe bronchial asthma. Rheumatologists and dermatologists long ago recognized the importance of replacing corticosteroids with other agents. Some agents such as methotrexate are now clearly established through multiple double-blind trials as being appropriate substitutes for corticosteroids, whereas other agents which have been investigated, such as cyclosporin, are very promising. Finally, a third group of agents, including troleandomycin (TAO), have been found to be totally inappropriate as possible substitutes for corticosteroids.

Cytogenetic versus DNA diagnosis in routine referrals for fragile X syndrome

The molecular cloning of the gene that causes the fragile X syndrome, and the demonstration that the causative mutation is an expansion of an unstable trinucleotide repeat, suggests that cytogenetic testing could be replaced by a molecular test. We compared the two methods in 525 routine referrals. 12 cases were positive in both tests. 1 case that had a negative DNA test for the fragile site at Xq27.3 (FRAXA), but a positive cytogenetic result, was shown to be caused by a mutation at the FRAXE locus on chromosome Xq28. DNA analysis is a sensitive, reliable, and cost-effective diagnostic alternative.

Complete and partial XY sex reversal associated with terminal deletion of 10q: report of 2 cases and literature review

We describe 2 karyotypically male infants with terminal deletion of 10q and mental retardation, multiple phenotypic anomalies and abnormal genitalia. One [karyotype 46,XY, del(10)(q26.1)] had female external genitalia; the other [karyotype 46,XY,-10,+der(10)t (10;16)(q26.2;q21)] had an intersex phenotype. Of 8 males previously reported with terminal 10q deletion as the major or only cytogenetic abnormality, 2 had an intersex phenotype, and the others all had combinations of cryptorchidism, micropenis, and hypospadias. Terminal 10q deletions appear to be strongly associated with abnormal male genital development, and should be specifically searched for in the cytogenetic workup of such cases.

Effect of ultrasound on chromosomes of lymphocyte cultures

In-vitro experiments have been undertaken to assess the effect of ultrasound at diagnostic and therapeutic levels on chromosomes of human lymphocyte cultures. The frequency used was about 2 MHz. The intensity was that of diagnostic level, 23 mW/cm(2), which was increased stepwise to 3.5 W/cm(2). The time of exposure varied from two to eight hours. No difference could be detected between the numbers of cells with aberrations in the insonated and control cultures, but aggregation of red cells was observed at high intensities.

Study of chromosomes in the newborn after ultrasonic fetal heart monitoring in labour

The effect of continuous-wave ultrasound on the chromosomes of newborn infants has been investigated. Twenty-four women were studied during labour. The fetal heart was monitored by a Sonicaid FM2 monitor applied to the abdomen, and continuous monitoring undertaken for intervals varying from 1 hour 5 minutes to 9 hours 25 minutes. There was no increase in the number of chromosome aberrations in cultures of blood taken from the insonated babies when compared with controls.

Cellular immunity in casein-induced amyloidosis

Guinea-pigs receiving multiple subcutaneous injections of casein at first developed a cellular immune response to casein but this rapidly waned when the animals became amyloidotic. By contrast, cellular immune responsiveness to non-specific antigens at first appeared to be diminished but later returned to normal under the same conditions. These results suggest that tolerance to a specific immunogen may play an important role in the pathogenesis of casein-induced amyloidosis.