Formaldehyde in cryoprotectant propanediol and effect on mouse zygotes

Cryopreservation of human zygotes and embryos has been routinely performed by in-vitro fertilization clinics for many years. Karran and Legge (1996) first reported that formaldehyde (FA) present in the cryoprotective solutions can have a deleterious effect on mouse oocytes. FA is a cytotoxic, carcinogenic and mutagenic chemical. The effect of FA on mouse zygotes was investigated. In addition, the concentrations of FA in propanediol (PROH) obtained from various sources were determined. Pooled 1-cell embryos were dispensed into droplets of modified Ham's F10 or human tubal fluid containing various concentrations of FA. Since bovine serum albumin (BSA) may minimize toxicity additional trials were done as above in the absence of BSA. FA concentration in the standard 1.5 M PROH, from different sources in water, was measured in the same assay using a standard curve of 0-100 microM FA. FA in a complex medium had a significant deleterious effect on embryo development and hatching but only at 1 mM concentration (P < 0.000001; see Tables I-III). There was no significant effect of FA at 100 microM. However, in a simple medium even 50 microM FA decreased embryo hatching. FA was present in 1.5 M PROH from different sources (range 1.0-35.3 microM concentration). It appears that FA concentrations do not increase with storage because FA concentrations were low even after opening and storage for 3 years on the shelf. This suggests that FA is a contaminant during the manufacturing process and may vary from manufacturer to manufacturer and batch to batch. Until further studies are done to confirm the lack of toxicity to embryos during cryopreservation (with or without FA scavengers) it may be prudent to screen all batches of cryoprotectants for FA as part of quality control.      

BRCA1 and pancreatic cancer: pedigree findings and their causal relationships

Anecdotal reports and series studies indicate that 5-10% of pancreatic cancer (PC) cases are familial. In addition, PC is associated with a variety of hereditary cancer syndromes. PC appears to be an integral cancer in the hereditary breast-ovarian cancer (HBOC) syndrome, with most notice given to the role of BRCA2. Our purpose is to call attention to BRCA1, which also predisposes to PC. Using data from our familial breast cancer registry, we identified 19 BRCA1/2 families that contain PC affecteds in the pedigrees, 15 with BRCA1 mutations and 4 with BRCA2 mutations. The association between BRCA2 and pancreatic cancer is well established; however, a definite link with pancreatic cancer in families carrying a BRCA1 mutation has been far less studied. Thus, the focus of this report is on 9 of the 15 BRCA1 families, in which PC affecteds were either confirmed carriers of the BRCA1 mutation or were inferred as probable obligate BRCA1 mutation carriers. The numbers are small, but nevertheless illustrate the finding of others of an apparent association between PC and BRCA1-mutation-bearing families. Given the dismal prognosis of PC, with the only current hope for survival being through surgical extirpation of the pancreas prior to metastasis, it is prudent that we realize the potential predisposition toward PC via BRCA1, in the hope of early diagnosis and prevention.     

Expression of PKC-beta or cyclin D2 predicts for inferior survival in diffuse large B-cell lymphoma.

We sought to determine whether identification of poor-risk subgroups of diffuse large B-cell lymphoma (DLBCL) using immunohistochemical stains would have practical utility with regard to prognosis and therapeutic decisions. Tissue microarray blocks were created using replicate samples of formalin-fixed, paraffin-embedded tissue from 200 cases of de novo DLBCL. The sections were stained with antibodies to proteins that are expressed by activated or proliferating B cells including MUM1, FOXP1, bcl-2, survivin, protein kinase C-beta (PKC-beta), cyclin D2, cyclin D3, and Ki-67. In univariate analysis, tumor expression of cyclin D2 (P = 0.025) or PKC-beta (P = 0.015) was associated with a worse overall survival, whereas none of the other markers was predictive of overall survival. Patients with DLBCL that expressed either cyclin D2 or PKC-beta had a 5-year overall survival of only 30% as compared to 52% for those who were negative for both markers (P = 0.0019). In multivariate analysis, the expression of cyclin D2 or PKC-beta was an independent predictor of poor overall survival (P = 0.035). Cyclin D2 and PKC-beta expression will be useful in designing a 'biological prognostic index' for patients with DLBCL.     

Interlaboratory validation of a CD71-based flow cytometric method (Microflow) for the scoring of micronucleated reticulocytes in mouse peripheral blood

An interlaboratory study was performed to validate an anti-CD71/flow cytometry-based technique for enumerating micronucleated reticulocytes (MN-RETs) in mouse peripheral blood. These experiments were designed to address International Workshop on Genotoxicity Test Procedures validation criteria by evaluating the degree of correspondence between MN-RET measurements generated by flow cytometry (FCM) with those obtained using traditional microscopy-based methods. In addition to these cross-methods data, flow cytometric MN-RET measurements for each blood sample were performed at two separate sites in order to evaluate the reproducibility of data between laboratories. In these studies, groups of male CD-1 mice were treated with vehicle (saline or vegetable oil), a negative control (saline or vegetable oil), or four dose levels of five known genotoxicants (clastogens: cyclophosphamide, benzo[a]pyrene, 5-fluorouracil, methotrexate; aneugen: vincristine sulfate). Exposure occurred on 3 consecutive days via intraperitoneal injection, and blood samples were obtained approximately 24 hr after the final treatment. MN-RET frequencies were determined for each sample based on the analysis of 2,000 (microscopy) and 20,000 (FCM) reticulocytes. Regardless of the method utilized, each genotoxic agent was observed to cause statistically significant increases in the frequency of MN-RETs, and each response occurred in a dose-dependent manner. Spearman's correlation coefficient (rs) for FCM versus microscopy-based MN-RET measurements (nine experiments, 252 paired measurements) was 0.740, indicating a high degree of correspondence between methods. The rs value for all flow cytometric MN-RET measurements performed at the two independent sites was 0.857 (n = 248), suggesting that the automated method is highly transferable between laboratories. Additionally, the flow cytometric system offered advantages relative to microscopy-based scoring, including a greater number of cells analyzed, much faster analysis times, and a greater degree of objectivity. Collectively, data presented in this report suggest that the overall performance of mouse peripheral blood micronucleus tests is enhanced by the use of the flow cytometric scoring procedure.     

A 10-Mb paracentric inversion of chromosome arm 2p inactivates MSH2 and is responsible for hereditary nonpolyposis colorectal cancer in a North-American kindred

Genomic deletions of the MSH2 gene are a frequent cause of hereditary nonpolyposis colorectal cancer (HNPCC), a common hereditary predisposition to the development of tumors in several organs including the gastrointestinal and urinary tracts and endometrium. The mutation spectrum at the MSH2 gene is extremely heterogeneous because it includes nonsense and missense point mutations, small insertions and deletions leading to frameshifts, and larger genomic deletions, the latter representing approximately 25% of the total mutation burden. Here, we report the identification and molecular characterization of the first paracentric inversion of the MSH2 locus known to cause HNPCC. Southern blot analysis and inverse PCR showed that the centromeric and telomeric breakpoints of the paracentric inversion map within intron 7 and to a contig 10 Mb 3' of MSH2, respectively. Pathogenicity of the paracentric inversion was demonstrated by conversion analysis. The patient's lymphocytes were employed to generate somatic cell hybrids to analyze the expression of the inverted MSH2 allele in an Msh2-deficient rodent cellular background. The inversion was shown to abolish MSH2 expression by both northern and western analysis. This study confirms that Southern blot analysis still represents a useful and informative tool to screen for and identify complex genomic rearrangements in HNPCC. Moreover, monoallelic expression analysis represents an attractive approach to demonstrate pathogenicity of unusual mutations in autosomal dominant hereditary conditions.     

Apolipoprotein A-I and A-II levels in an Australian population

Values for apolipoproteins A-I and A-II (apo A-I and apo A-II) are reported for 389 women and 390 men in the town of Busselton, Western Australia. Apo A-I levels were found to be relatively constant with age in men but to rise with age in women. Apo A-II levels remained constant with age in men until older age, when they declined, but rose with age in women, showing a fall in the oldest age group. Apo A-I levels were greater in women than in men, but apo A-II levels were lower in younger women than in younger men, and higher in older women than in older men. On stepwise multiple regression analysis, neither apo A-I nor apo A-II levels showed an independent relationship with age in women; the same was true for apo A-I in men. Alcohol consumption was directly associated with apo A-I and A-II levels in both sexes; adiposity was inversely associated with apo A-I levels in both sexes but with apo A-II only in women. Triglyceride levels showed an inverse association with apo A-II in women. Frequency of exercise was independently and directly associated with apo A-I and A-II levels in women only.     

Prenatal diagnosis with repetitive in situ hybridization probes

We have used chromosome-specific repetitive sequences to detect the most common human aneuploidies prenatally. Together chromosome 21, 13, 18, X, and Y aneuploidy comprises 95% of the chromosome abnormalities that result in a high risk of abnormal phenotypes at birth. The X, Y, and 18 repetitive probes work reliably in multiple tissue types including directly examined and cultured amniocytes, chorionic villus cells, lymphocytes, and cultured fibroblasts. The probe that detects both chromosomes 13 and 21 routinely gives results in each cell type tested except directly studied amniocytes which can be interpreted in seven-ninths of the cases with protocol 1 and all tested samples with protocol 2. Our protocols diagnosed trisomy 21 in a 23-week fetus with low maternal serum AFP and a trisomy 18 in a direct chorionic villus sample 2 working days after the samples were obtained. Trisomy 21 also has been ruled out in a CVS karyotype first thought to be 47,XY,+21. These studies reflect the potential value of in situ hybridization to provide a more rapid, less expensive means to screen most at-risk fetal populations with less effort in first world cytogenetic laboratories, and to provide economical cytogenetic services in less developed countries. © 1992 Wiley-Liss, Inc.     

Who supports the support workers? Cross-sectional survey of support workers' experience and views

Support groups provide information and emotional support to families. Despite a recent growth in the number and size of these groups, there are no formal structures in place to provide support for the support worker. We performed a cross-sectional survey using a self-completion postal questionnaire, with the aim of identifying the structure, training needs and support given to workers. The participants were support workers from 112 United Kingdom-based organisations listed on the 'Contact a Family' website (www.cafamily.co.uk). We received 104 replies from 50/112 organisations (44%). Of these, 94/104 (90%) worked from home as volunteers. Two-thirds, 69/104, admitted times when they struggled to cope. A total of 43 (41%) admitted occasions of concern over the care given by a client to their affected relative. No group employed a professional to act in a clinical supervisory role. Our study suggests that support workers are highly committed to their role; these workers need support to ensure that they give appropriate advice under difficult circumstances.