Array comparative genomic hybridization and flow cytometry analysis of spontaneous abortions and mors in utero samples

Background  

It is estimated that 10-15% of all clinically recognised pregnancies result in a spontaneous abortion or miscarriage. Previous studies have indicated that in up to 50% of first trimester miscarriages, chromosomal abnormalities can be identified. For several decades chromosome analysis has been the golden standard to detect these genomic imbalances. A major drawback of this method is the requirement of short term cultures of fetal cells. In this study we evaluated the combined use of array CGH and flow cytometry (FCM), for detection of chromosomal abnormalities, as an alternative for karyotyping.     

Diagnostic tests for kala-azar: a multi-centre study of the freeze-dried DAT, rK39 strip test and KAtex in East Africa and the Indian subcontinent

Three diagnostic tests for visceral leishmaniasis (VL), the freeze-dried direct agglutination test (FD-DAT), the rK39 dipstick and a urine latex antigen test (KAtex), were evaluated for use in primary care in East Africa and the Indian subcontinent. Clinical suspects were prospectively recruited and tissue, blood and urine samples were taken. Direct microscopic examination of tissue smear, and FD-DAT, rK39 and KAtex were performed. Sensitivity and specificity with 95% credible intervals were estimated using Bayesian latent class analysis. On the Indian subcontinent both the FD-DAT and the rK39 strip test exceeded the 95% sensitivity and 90% specificity target, but not so in East Africa. Sensitivity of the FD-DAT was high in Ethiopia and Kenya but lower in Sudan, while its specificity was below 90% in Kenya. Sensitivity of the rK39 was below 80% in the three countries, and its specificity was only 70% in Ethiopia. KAtex showed moderate to very low sensitivity in all countries. FD-DAT and rK39 can be recommended for clinical practice on the Indian subcontinent. In East Africa, their clinical use should be carefully monitored. More work is needed to improve existing formats, and to develop better VL diagnostics.     

Determination of antigen concentration in tissue sections by immunodensitometry

Our aim was to determine whether density of immunolabeling can be used to estimate the amount of an antigen in a tissue. The biological model was the pancreatic insulin-containing B cell. The insulin content of the pancreas of Wistar rats was decreased by five injections of glibenclamide (0.5, 1, or 2 mg/kg) every 12 hours. After resection of the whole pancreas specimens were taken for insulin extraction and measurement by radioimmunoassay and for immunocytochemistry. The sections were treated either by a polyclonal anti-insulin serum at 1/500 or 1/3000 and peroxidase-antiperoxidase complex or by a monoclonal anti-insulin serum at 1/500 and indirect immunoperoxidase. Peroxidase was revealed by diaminobenzidine. The density of immunostained B cells was determined with an automatic image analyzer (Ibas 2000, Kontron, FRG). Compared with controls, pancreatic insulin concentration was decreased by about 40, 60, and 85% in rats treated by the three doses of glibenclamide. A strong correlation was found between the insulin concentration and the optical density of islets under certain conditions: with the monoclonal anti-insulin serum (r = 0.90) and with the polyclonal anti-insulin serum at a high dilution (r = 0.95) but not at a low dilution (r = 0.13). With the latter, the optical density was high even in islets with reduced insulin content. In conclusion, a low dilution of antiserum should be used to detect cells with a small amount of antigen, whereas a higher dilution makes it possible to estimate the antigen concentration in the tissue. Thus, under appropriate conditions, a linear relationship exists between the optical density of the immunostained material and the concentration of immunoassayable antigen. This technique may thus prove useful in evaluating the functional state of cells, in particular secretory cells, under normal or pathological conditions.     

Salvage PCV chemotherapy for temozolomide-resistant oligodendrogliomas

The authors investigated the results of PCV chemotherapy within a cohort of 24 patients treated within the EORTC study 26971 on temozolomide chemotherapy in recurrent oligodendroglioma. The genotype of the tumors was assessed with fluorescent in situ hybridization with locus specific probes for the region 1p36. Four of the 24 patients responded (17%). Fifty percent of patients were still free from progression at 6 months and 21% were free from progression at 12 months. Although a clear relation existed between loss of 1p and response to temozolomide chemotherapy, this relation was absent in salvage PCV chemotherapy.     

Temozolomide for the Treatment of Recurrent Supratentorial Glioma: Results of a Compassionate use Program in Belgium

Temozolomide (TMZ) has demonstrated activity and acceptable toxicity for the treatment of recurrent high-grade gliomas in prospective phase II studies. Limited information is available on TMZ when prescribed outside a clinical trial. We conducted a retrospective study to evaluate the activity and safety of TMZ that was prescribed for the treatment of recurrent glioma in the context of a compassionate use program in Belgium. Data were obtained on 117 adult patients (from five hospitals) who received TMZ as first or second line chemotherapy. The recommended starting dose of TMZ was 200 mg/m2 x5d q28d for chemonaive patients and 150 mg/m2 x5d q28d for pre-treated patients. Toxicity was generally mild. Thrombocytopenia was the most frequent treatment related adverse event (grade 3/4 in 17% of patients). Its occurrence was correlated with a starting dose of 200 mg/m2/d and stresses the need to monitor toxicity. The overall objective response rate (complete and partial response) was 29 and 34% of patients achieved an objective disease stabilization. The median progression-free survival was 104 days (95% CI: 85-123) and the median overall survival was 215 days (95% CI: 161 269). In multivariate analysis a 'deep localization' of the glioma (as opposed to a cortico-subcortical localization) and 'the preceding history of a low-grade glioma' were respectively identified as a negative and positive independent prognostic variable for survival. No significant difference in terms of response or median survival was observed between patients with anaplastic astrocytoma or oligo-astrocytoma and chemonaive glioblastoma multiforme. This retrospective study indicates that the reported activity and toxicity profile of TMZ for the treatment of patients with recurrent glioma is reproducible outside the setting of a prospective clinical trial.     

ArrayCGH-based classification of neuroblastoma into genomic subgroups

High-resolution array comparative genomic hybridization (arrayCGH) profiling was performed on 75 primary tumors and 29 cell lines to gain further insight into the genetic heterogeneity of neuroblastoma and to refine genomic subclassification. Using a novel data-mining strategy, three major and two minor genomic subclasses were delineated. Eighty-three percent of tumors could be assigned to the three major genomic subclasses, corresponding to the three known clinically and biologically relevant subsets in neuroblastoma. The remaining subclasses represented (1) tumors with no/few copy number alterations or an atypical pattern of aberrations and (2) tumors with 11q13 amplification. Inspection of individual arrayCGH profiles showed that recurrent genomic imbalances were not exclusively associated with a specific subclass. Of particular notice were tumors with numerical imbalances typically observed in subtype 1 neuroblastoma, in association with genomic features of subtype 2A or 2B. A search for prognostically relevant genomic alterations disclosed 1q gain as a predictive marker for therapy failure within the group of subtype 2A and 2B tumors. In cell lines, a high incidence of 6q loss was observed, with a 3.87-5.32 Mb region of common loss within 6q25.1-6q25.2. Our study clearly illustrates the importance of genomic profiling in relation to tumor behavior in neuroblastoma. We propose that genome-wide assessment of copy number alterations should ideally be included in the genetic workup of neuroblastoma. Further multicentric studies on large tumor series are warranted in order to improve therapeutic stratification in conjunction with other features such as age at diagnosis, tumor stage, and gene expression signatures.     

Osteopoikilosis, short stature and mental retardation as key features of a new microdeletion syndrome on 12q14

This report presents the detection of a heterozygous deletion at chromosome 12q14 in three unrelated patients with a similar phenotype consisting of mild mental retardation, failure to thrive in infancy, proportionate short stature and osteopoikilosis as the most characteristic features. In each case, this interstitial deletion was found using molecular karyotyping. The deletion occurred as a de novo event and varied between 3.44 and 6 megabases (Mb) in size with a 3.44 Mb common deleted region. The deleted interval was not flanked by low-copy repeats or segmental duplications. It contains 13 RefSeq genes, including LEMD3, which was previously shown to be the causal gene for osteopoikilosis. The observation of osteopoikilosis lesions should facilitate recognition of this new microdeletion syndrome among children with failure to thrive, short stature and learning disabilities.     

Report of a female patient with mental retardation and tall stature due to a chromosomal rearrangement disrupting the OPHN1 gene on Xq12

We report on a patient with mental retardation, seizures and tall stature with advanced bone age in whom a de novo apparently balanced chromosomal rearrangement 46,XX,t(X;9)(q12;p13.3) was identified. Using array CGH on flow-sorted derivative chromosomes (array painting) and subsequent FISH and qPCR analysis, we mapped and sequenced both breakpoints. The Xq12 breakpoint was located within the gene coding for oligophrenin 1 (OPHN1) whereas the 9p13.3 breakpoint was assigned to a non-coding segment within a gene dense region. Disruption of OPHN1 by the Xq12 breakpoint was considered the major cause of the abnormal phenotype observed in the proband.