Oviductal extracellular vesicles interact with the spermatozoon's head and mid-piece and improves its motility and fertilizing ability in the domestic cat

Fertilization and early embryo development are regulated by a unique maternal-gamete/embryo cross-talk within the oviduct. Recent studies have shown that extracellular vesicles (EVs) within the oviduct play important roles in mediating this developmental process. Here, we examined the influence of oviductal EVs on sperm function in the domestic cat. We demonstrated that (1) EVs are enriched in proteins related to energy metabolism, membrane modification, and reproductive function; (2) EVs bound and fused with the membranes of the acrosome and mid piece; and (3) incubating sperm with EVs improved motility, fertilizing capacity of cat spermatozoa and prevented acrosomal exocytosis in vitro. These findings indicated that oviductal EVs mediate sperm function and fertilization in the cat and provides new insights to improve sperm cryopreservation and in vitro fertilization in the domestic and wild felids and human.

207 Cat oviductal exosomes as a tool to improve gamete rescue of endangered felids: effects on sperm capacitation and in vitro fertilization

Exosomes play important roles in reproduction, for example, facilitating fetal-maternal interaction and establishment of pregnancy. However, little is known about how oviductal exosomes affect sperm function. We investigated the effects of oviductal exosomes on sperm capacitation and fertilizing ability in domestic cats as a model for endangered felids. Oviducts were collected from cats (1-5 years) after elective spaying and flushed with 1mL of PBS. Exosomes (EX) were isolated using the Total Exosome Isolation kit (Invitrogen/Thermo Fisher Scientific, Waltham, MA, USA) and labelled with BODIPY dye (boron dipyrromethene). Unattached dye was removed by using Exosome Spin Columns (MW 3000, Invitrogen). Presence and purity of EX was confirmed by transmission electron microscopy (TEM). To investigate the effects of EX on sperm capacitation, semen was recovered from epididymis of 5 cats (3 replicates) after elective neutering. One million spermatozoa mL−1 were incubated with or without EX (1V sperm to 2V total exosomes from 2 oviducts) for 1h in PBS. The samples were then incubated at 38.5°C in 1 of the 2 conditions: (1) capacitation (SOF medium+1000IU of penicillin, 10μg mL−1 streptomycin, 10μg mL−1 heparin, 20 µM penicillamine, 10 µM hypotaurine, 1 µM epinephrine); and (2) non-capacitation (capacitation medium without heparin, penicillamine, or hypotaurine) for up to 24h. Total motility, hyperactive and progressive motility, and percentage of intact acrosomes (FITC-PNA) were assessed at 0, 1, 2, 18, and 24h. Data were analysed by using SPSS software (IBM Corp., Armonk, NY) using a paired samples t-test with 95% CI. Vesicles of 30-100nm were observed by TEM, indicating successful isolation of EX, which were found to bind to both acrosome and mid-piece (BODIPY labelling). Sperm incubated with EX exhibited higher motility than those without EX (P<0.05 for all comparisons) at 1h (capacitation: 80±3.7v. 70±3.5; non-capacitation: 78±1.6v. 66±2.5%), 2h (capacitation: 77±1.3v. 61±1.1; non-capacitation: 74±0.9v. 55±3.5%), 18h (capacitation: 53±1.5v. 40±4.7; non-capacitation: 30±1.2v. 21±3.7%), and 24h (capacitation: 30±2.5v. 12±1.1; non-capacitation: 21±2.1v. 8±0.9%). Regarding progressive and hyperactive motility and acrosome integrity, only hyperactive motility at 1h using capacitation medium was significantly higher in the presence of EX than without it (18±1.5v. 9±2.7%; P<0.05). Next, we performed IVF using sperm with or without 1h incubation with EX. After 18h IVF, presumptive zygotes were stained with Hoechst 33342 and observed under a fluorescence microscope to assess fertilization and polyspermy. Preliminary data (30 oocytes/group) revealed that sperm incubation with EX reduced polyspermy (6±4% v. 20±8%) and improved normal fertilization (28±14vs 8±4%), although the differences were not significantly different (P>0.05 for both groups). In conclusion, the findings indicate that oviductal EX play roles in regulating sperm function by enhancing sperm motility. Further studies are needed to confirm the impact of EX on fertilization and how this strategy can be applied to endangered felid conservation.

The Mobilization and Effect of Endogenous Bone Marrow Progenitor Cells in Diabetic Wound Healing

Diabetic patients suffer from impaired wound healing, characterized by only modest angiogenesis and cell proliferation. Stem cells may stimulate healing, but little is known about the kinetics of mobilization and function of bone marrow progenitor cells (BM-PCs) during diabetic wound repair. The objective of this study was to investigate the kinetics of BM-PC mobilization and their role during early diabetic wound repair in diabetic db/db mice. After wounding, circulating hematopoietic stem cells (Lin-c-Kit+Sca-1+) stably increased in the periphery and lymphoid tissue of db/db mice compared to unwounded controls. Peripheral endothelial progenitor cells (CD34+VEGFR+) were 2.5- and 3.5-fold increased on days 6 and 10 after wounding, respectively. Targeting the CXCR4—CXCL12 axis induced an increased release and engraftment of endogenous BM-PCs that was paralleled by an increased expression of CXCL12/SDF-1α in the wounds. Increased levels of peripheral and engrafted BM-PCs corresponded to stimulated angiogenesis and cell proliferation, while the addition of an agonist (GM-CSF) or an antagonist (ACK2) did not further modulate wound healing. Macroscopic histological correlations showed that increased levels of stem cells corresponded to higher levels of wound reepithelialization. After wounding, a natural release of endogenous BM-PCs was shown in diabetic mice, but only low levels of these cells homed in the healing tissue. Higher levels of CXCL12/SDF-1α and circulating stem cells were required to enhance their engraftment and biological effects. Despite controversial data about the functional impairment of diabetic BM-PCs, in this model our data showed a residual capacity of these cells to trigger angiogenesis and cell proliferation.

Population carrier frequency of hMSH2 and hMLH1 mutations

Knowledge of population carrier frequency for DNA mismatch repair (MMR) gene mutations would contribute to understanding the burden of cancer due to genetic susceptibility, but robust prevalence estimates are lacking. To estimate carrier frequency, we genotyped a cohort of relatives of mutation carriers and determined their colorectal cancer prevalence. Systematic Finnish and US data were combined with Scottish genotype and cancer prevalence data in a Bayesian calculation. The estimated carrier prevalence in the population aged 15-74 years is 1:3139 (95% Cl = 1:1247-1:7626) and these carriers are at high risk of colorectal and other cancers.

Pitfalls in homozygosity mapping

There is much interest in use of identity-by-descent (IBD) methods to map genes, both in Mendelian and in complex disorders. Homozygosity mapping provides a rapid means of mapping autosomal recessive genes in consanguineous families by identifying chromosomal regions that show homozygous IBD segments in pooled samples. In this report, we point out some potential pitfalls that arose during the course of homozygosity mapping of the enhanced S-cone syndrome gene, resulting from (1) unexpected allelic heterogeneity, so that the region containing the disease locus was missed as a result of pooling; (2) identification of a homozygous IBD region unrelated to the disease locus; and (3) the potential for inflation of LOD scores as a result of underestimation of the extent of inbreeding, which Broman and Weber suggest may be quite common.

apolipoprotein-E dependent role for the FAS receptor in early onset Alzheimer's disease: finding of a positive association for a polymorphism in the TNFRSF6 gene

The TNFRSF6 gene encodes FAS, a cell-surface receptor involved in apoptosis initiation. Elevated levels of FAS have been reported in the brains of Alzheimer's disease (AD) patients. We have tested a G/A polymorphism at position -670 in the TNFRSF6 gene for association with non-familial, early onset Alzheimer's disease (EOAD) by using dynamic allele-specific hybridization. In an initial set of Scottish EOAD cases (n=78) and controls (n=152), we found that, for individuals carrying one or two APOE4 alleles, the homozygous GG-genotype was enriched in the patients (26.7% versus 10.9% in controls). A second study was conducted on an independent set of Scottish individuals (87 EOAD, 358 controls). In this material, the TNFRSF6 GG-genotype frequency was elevated in patients regardless of APOE4 status (28.7% versus 15.1%) and was even more enriched in APOE4 carriers (35.9% versus 15.3%). A combination of the two sample sets (165 cases, 510 controls) gave a significant disease association for the TNFRSF6 GG-genotype that was irrespective of APOE4 (P=0.0020) and that was almost completely attributable to the enrichment present within the set of APOE4 carriers (P=0.0016). This represents an odds ratio of 8.71 for GG-homozygotes carrying at least one APOE4 allele compared with other TNFRSF6 genotypes in APOE4 non-carriers. The TNFRSF6 variation was further explored in Scottish late-onset Alzheimer's disease (n=159) but no associations were found. These results imply that TNFRSF6, in interaction with APOE4, is a genetic risk factor for sporadic EOAD. Hence, the AD risk contributed by APOE4 could be mechanistically related to a pathway in common with FAS-mediated apoptosis.

Increased levels of sister chromatid exchanges in military aircraft pilots

Sister chromatid exchanges (SCEs) were scored in lymphocytes of nine high-performance pilots of alphajet aircrafts and of ten control individuals from the same air base. Statistical analysis of the mean SCE count per cell in the total number of cells analyzed as well as in those having 12 or more SCEs (high-frequency cells, HFCs) revealed a significant difference between pilots and controls, after adjusting for the effect of smoking. Analysis of the cell cycle kinetic data (replication and mitotic indices) revealed no significant differences either between pilots and controls or between smokers and nonsmokers. Previously, we reported an increase in the SCE levels in workers of the aeronautical industry exposed to noise and whole-body vibration. The present results corroborate those findings and indicate that noise and whole-body vibration may cause genotoxic effects in man.

Sister chromatid exchange analysis in workers exposed to noise and vibration

BACKGROUND

There has been a growing interest in the combined effects of noise and vibration. In a population of aeronautical workers diagnosed with vibroacoustic disease (VAD), a large incidence of malignancy was detected. These workers were exposed to large pressure amplitude (LPA) (> or = 90 dB SPL) noise, with energy content concentrated within the low frequency (LF) bands (< or = 500 Hz) and whole-body vibration (WBV). To our knowledge, there are no studies conducted in humans or animals that address the issue of the potential genotoxic effects of vibration combined with noise. In the present study, the levels of sister chromatid exchanges (SCE) and of cells with high frequencies of SCE (HFC) were analyzed in peripheral blood lymphocytes of workers employed in various occupations within the aeronautical industry.

METHODS

SCE and HFC were analyzed in lymphocytes of 50 workers occupationally exposed to noise and vibration and of 34 office-worker controls (G0). The exposed group included: 10 hand-vibrating tool operators (G1), 15 engine test cell technicians (G2), 12 aircraft run-up technicians (G3) and 13 Portuguese Air Force helicopter pilots (G4). Groups 2-4 were exposed to WBV and LPALF noise; group 1 was exposed to LPA high frequency noise and local vibration. Statistical analysis of the mean SCE count per cell was carried out by multiple regression analysis comparing various predictor variables: type of exposure, duration of exposure, age, and cigarette consumption.

RESULTS

Only cigarette consumption and type of exposure were found to be significantly correlated with the mean SCE frequency. After allowing for the effects of smoking, the analysis indicates that: 1) there was no significant difference between G1 and G0 (p > 0.05); 2) the differences between G2 and G0, G3 and G0, G4 and G0 were all highly significant (p < 0.001); 3) there was no significant difference between G2 and G3 (p > 0.05), nor between G2 and G3 combined and G4 (p > 0.05); and 4) G2 and G4 combined had a significantly elevated mean SCE frequency compared G0 (p < 0.001). Statistical analysis of the proportion of HFC was consistent with these results.

CONCLUSION

Our data suggest that occupational exposure to LPALF noise and WBV may lead to increased levels of SCE in men. These results also suggest a reason for the high incidence of malignancy in VAD patients. The observed effects may not reflect a direct action of these physical agents on DNA. Alternative explanations may lie in the noise-, vibration-, and/or stress-induced pathophysiological changes.

Correlation between nasal potential difference measurements, genotype and clinical condition in patients with cystic fibrosis

In cystic fibrosis (CF), the clinical condition of patients correlates poorly with genotype. One possible explanation is that clinical status is influenced by net preserved chloride secretion rather than the CF mutation. We tested the relationships between residual chloride secretion, as measured by nasal potential difference (PD) and the type of mutation (genotypes expressing apical cystic fibrosis transmembrane conductance regulator (CFTR) protein versus those that do not) and clinical status. Twenty two CF patients (mean age 25.7 yrs, 11 females and 11 males, mean forced expiratory volume in one second (FEV1) 53.1% of predicted) with defined genotypes were recruited. Nasal PD was measured using a standard protocol involving the perfusion of the nasal epithelium with a sodium channel blocker (amiloride), followed by a solution of low chloride and finally with isoprenaline. Patients with apical CFTR protein showed higher residual chloride secretion than those without (amiloride to isoprenaline value of 4.59 and 0.56 mV, respectively, p = 0.01). There was no correlation between mutation type and clinical condition. When these patients were recategorized as "high" (> 10 mV amiloride to isoprenaline response) or "low" (10 mV or less) chloride secretors, we found that the former group had a significantly higher FEV1 (67.7 versus 48.3% pred) and a better pulmonary radiological score (4.14 versus 7.07, by Northern scoring system). These results suggest that some cystic fibrosis patients, regardless of genotype, have an ability to secrete chloride when stimulated with chloride secretatagogues, and this is correlated with a better lung function. These results also have implications for the use of potential difference measurements in novel cystic fibrosis transmembrane conductance regulator replacement trials.

The Asp84Glu variant of the melanocortin 1 receptor (MC1R) is associated with melanoma

Melanocyte stimulating hormone (MSH) plays an important role in determining the cutaneous response to ultraviolet radiation and may also influence melanoma progression. We have previously shown that variants of the melanocortin receptor present on melanocytes, MC1R, are associated with sun sensitivity and red hair in a UK population and therefore now consider the gene as a candidate for melanoma susceptibility. We have compared the frequency of known MC1R variants in the second and seventh transmembrane domains in 43 melanoma cases and 44 controls. MC1R variants were more common in cases than controls (chi 2 = 6.75, 1 d.f.; P = 0.0094) with a relative risk to carriers of variant alleles compared with normal homozygotes of 3.91 (95% c.l.: 1.48-10.35), and a population risk attributable to carriers of 34.6% (95% c.i. 10.7-52.1%). The Asp84Glu variant was only present in melanoma cases and appears to be of particular significance. The contribution of variant MC1R alleles was largely independent of skin type. Variants of the MC1R gene are likely to be causally associated with the development of melanoma.

Sister chromatid exchange analysis in workers exposed to noise and vibration

Workers chronically exposed to whole-body vibration and noise are known to develop pathophysiological and psychological disturbances. The frequencies of sister chromatid exchanges (SCEs) and of cells with high frequencies of SCEs (HFCs) were analyzed in lymphocytes of 50 workers occupationally exposed to vibration and noise and of 34 controls. The exposed group included: individuals operating hand-vibrating tools (group 1), 'test-cell operators' (group 2) and 'run-up' operators (group 3) from an air base and helicopter pilots (group 4). The statistical analysis of the mean SCE count per cell was carried out by multiple regression analysis, comparing various predictor variables: exposure group, duration of exposure, age and cigarette consumption. Only cigarette consumption and exposure group were found to be significantly correlated with the mean SCE frequency. After allowing for the effects of smoking, the analysis indicates that: (1) there was no significant difference between group 1 and controls (p > 0.05); (2) the differences between group 2 and group 0, group 3 and group 0 and group 4 and group 0 were all highly significant (p < 0.001); (3) there was no significant difference between groups 2 and 3 (p > 0.05), nor between groups 2 and 3 combined and group 4 (p > 0.05); (4) exposure groups 2, 3 and 4 combined, had a significantly elevated mean SCE frequency compared to the control group (p < 0.0001). Statistical analysis of the proportion of HFCs was consistent with these results. Our data suggest that chronic exposure to whole-body vibration and noise may lead to an increase in the level of SCEs in man. The observed effects may not reflect a direct action of these physical agents on DNA. Alternative explanations may include some of the whole-body vibration and noise-induced or stress-induced pathophysiological alterations which may indirectly induce SCE formation.

Recombination patterns around the breakpoints of a balanced 1;11 autosomal translocation associated with major mental illness

The frequency and extent of pairing failure around human translocations are unknown. We have examined the pattern of recombination around the breakpoints of a balanced autosomal translocation t(1;11) (q43;q21) associated with major mental illness. DNA was available from 17 carriers and 10 non-translocation carriers with meioses involving four generations. The derivative 1 and 11 chromosomes were also isolated in somatic cell hybrids and used to confirm phase. We have genotyped pedigree members using 20 polymorphic markers within 10 cM on either side of both chromosome 1 and 11 breakpoints. We find no significant reduction of recombination in the vicinity of either breakpoint. However we estimate that there are insufficient meioses even in this large family to make a meaningful interpretation and suggest that sperm typing alone can answer these interesting questions.

Apolipoprotein E epsilon 4 allele is a risk factor for familial and sporadic presenile Alzheimer's disease in both homozygote and heterozygote carriers

While apoliprotein E (ApoE) epsilon 4 allele is now a well established risk factor for familial and sporadic senile Alzheimer's disease (AD), its role in the development of the rarer presenile or early onset type is controversial. Early studies showed no association; later ones found enrichment for the epsilon 4 allele in familial or sporadic types or both. We have ApoE genotyped a series of Scottish people (n = 85) with early onset AD. We find highly significant enrichment for both homozygote and heterozygote ApoE epsilon 4 allele carriers in familial and sporadic early onset AD with a pattern closely resembling that in late onset AD.

A collaborative trial of a semi-automatic system for slide preparation and screening in cervical cytopathology

We report a test of an experimental system for machine-aided screening in cervical cytology, comprising the 'CYTOPRESS' semi-automatic slide preparation system (Nijmegen) and the 'CERVIFIP' interactive scanner (Edinburgh). Material from women attending clinics in Edinburgh and Nijmegen was stratified according to the severity of the conventional laboratory diagnosis and selected randomly within strata for inclusion in the test. Monolayered slides were prepared by CYTOPRESS from cervical scrape material remaining after preparation of conventional smears and scanned by CERVIFIP to determine the positions of the most 'suspicious' objects. The test was based on a set of 701 monolayers, divided equally between 'negatives' and 'abnormals' of various grades, of which 585 (83.4%) were passed automatically as adequate for machine-aided analysis. Approximately 15% of adequate slides were passed as 'negative' without operator interaction. In the remaining 85%, the suspicious objects were inspected by a human operator and a decision was then made either to refer each monolayer for conventional microscopic analysis, or to pass it as 'negative'. Where discrepancies occurred between the conventional laboratory and the system results, a consensus diagnosis was reached by taking into account all relevant information including clinical data. Of those with a consensus diagnosis of CIN 3 or worse an estimated 9.3 +/- 4.1% were passed by the system as 'negative'. Closer investigation of these false-negatives revealed that most, and perhaps all, were preventable by system improvements either planned or in progress. Corresponding false-negative rates for those graded 'CIN 1 or 2' and 'negative-early recall' were estimated, respectively as 18.9 +/- 5.3% and 22.9 +/- 3.1%. Of those with a 'negative-routine recall' consensus, 19.4 +/- 2.5% were referred for conventional microscopic analysis, a level well within acceptable limits for cost-effectiveness. Women whose initial laboratory smears were negative, but whose consensus diagnosis was 'negative-early recall' or CIN, are being investigated further to determine whether cervical abnormalities were in fact present. Over two-thirds of this group were referred by the machine-aided system for conventional microscopic analysis.

Dose dependence of radiation-induced micronuclei in cytokinesis-blocked human lymphocytes

Following selection of appropriate culture conditions, various experiments were conducted to evaluate the suitability of the micronucleus assay in cytokinesis-blocked lymphocytes for biological dosimetry purposes. A dose-effect relationship was determined, based on the frequency of micronuclei induced by various doses of 60Co gamma-rays. The data were best fitted to a linear-quadratic model. To validate the system, an attempt was made to estimate unknown dose levels from the yield of micronuclei, by inverting the derived dose-response function. It was concluded that the assay provides a valid approach for dose assessment. The size of radiation-induced micronuclei was measured in relation to the dose. A significant difference in the proportion of large micronuclei between high and low doses was observed. The chromosomal composition of micronuclei, detected by immunofluorescent staining of kinetochores, showed that only a small proportion of micronuclei contains kinetochore. The possible contribution of various mechanisms for the formation of large radiation-induced micronuclei is discussed.

Genetic linkage analysis applied to unaffected women from families with breast cancer can discriminate high- from low-risk individuals

Up to 20 per cent of cases of breast cancer diagnosed in women under the age of 45 years may be caused by an autosomal dominant gene. A present difficulty is differentiation of mutation carriers from non-mutation carriers in high-risk families. Genetic linkage analysis has been used to localize a susceptibility gene (BRCA1) on chromosome 17q12-21 between markers 42D6 and MFD188, a region 5-10 million base pairs in length. Odds in favour of linkage to this region were greater than 100,000:1 in 15 families with breast cancer. In eight families in which the probability of linkage was above 75 (range 79.2-99.9) per cent, 19 women were identified who were at high lifetime risk of breast cancer (range 80.6-87.2 per cent) and 37 whose risk was similar to that for the general population (range 9.8-16.4 per cent). Genetic risk prediction of this kind may enable high-risk screening clinic resources to be concentrated on those most likely to benefit.

Linkage of a major breast cancer gene to chromosome 17q12-21: results from 15 Edinburgh families

DNA from members of 15 pedigrees each containing between three and eight cases of breast cancer have been collected from southeastern Scotland. Polymorphic markers on chromosome 17q were screened to locate a putative breast cancer gene by using DNA from relevant individuals within these families. Pairwise LOD scores were calculated for markers D17S74, NM23, D17S588, and D17S579. The maximal summated LOD for the 15 families was 5.44 at theta = .034, when D17S588 (42D6) was used. In these breast cancer families, a subset which did not give evidence for linkage to this region could be identified.

Linkage mapping in familial breast cancer: improved localisation of a susceptibility locus on chromosome 17q12-21

Fifteen pedigrees with a total of 75 cases of breast cancer, 10 of ovarian cancer and 53 of other cancers have been collected. Polymorphic markers on chromosome 17q have been screened to locate a putative breast-cancer gene using DNA from relevant individuals within these families. Pairwise LOD scores have been calculated for markers CMM86, NM23, 42D6 and MFD188. The maximal summated LOD for the 15 families is 4.45 at theta = 0.025 using 42D6. All cases of bilateral breast cancer and ovarian cancer appear to be linked to this region. Recalculating LOD scores on the assumption of linkage in these cases increases the maximal summated LOD to 5.62 at theta = 0.025 using 42D6. A genetic exclusion map of critical recombinants in linked families suggests that the gene is flanked by markers 42D6 and MFD188, a region 5 to 10 cm in length.

Semi-automated cervical smear pre-screening systems: an evaluation of the Cytoscan-110

This paper reports a test of a system for provision of machine assistance in cervical cytology screening. The hypothesis tested was that if the results of examination by a screener of a small number of high-ploidy cells on specially prepared monolayers, automatically selected and presented by the system, were combined with machine measurement of cell and cell population characteristics, it would be possible to distinguish conditions requiring further action on the part of a cytology service from those in which the patient could safely be signed out. The system appeared broadly capable of this discrimination, with a false-negative error not significantly different (for the numbers tested) on CIN1 and more severe cases to that obtaining for routine screening of the parallel PAP smears, and also to results obtained by a panel of three observers. The machine system appeared to do better than other systems in selecting borderline cases for review, but this may have been an artefact of the method of evaluation used: all results were compared with a 'reference diagnosis', which was computed using statistical techniques to integrate diagnostic information from all available sources. The false-negative error-rate of the system amounted to 5% of high-grade cases, 17% of CIN1's and 29% of borderlines, but were not substantially different from the FN rates for other reporting systems on the same material. The proportion of negative cases referred back for full cytological diagnosis was 34%. Despite this high false-positive rate, the system is potentially cost-effective in use.

Radiation dosimetry by automatic image analysis of dicentric chromosomes

A system for scoring dicentric chromosomes by image analysis comprised fully automatic location of mitotic cells, automatic retrieval, focus and digitization at high resolution, automatic rejection of nuclei and debris and detection and segmentation of chromosome clusters, automatic centromere location, and subsequent rapid interactive visual review of potential dicentric chromosomes to confirm positives and reject false positives. A calibration set of about 15,000 cells was used to establish the quadratic dose response for 60Co gamma-irradiation. The dose-response function parameters were established by a maximum likelihood technique, and confidence limits in the dose response and in the corresponding inverse curve, of estimated dose for observed dicentric frequency, were established by Monte Carlo techniques. The system was validated in a blind trial by analysing a test set comprising a total of about 8000 cells irradiated to 1 of 10 dose levels, and estimating the doses from the observed dicentric frequency. There was a close correspondence between the estimated and true doses. The overall sensitivity of the system in terms of the proportion of the total population of dicentrics present in the cells analysed that were detected by the system was measured to be about 40%. This implies that about 2.5 times more cells must be analysed by machine than by visual analysis. Taking this factor into account, the measured review time and false positive rates imply that analysis by the system of sufficient cells to provide the equivalent of a visual analysis of 500 cells would require about 1 h for operator review.

Analysis of the origin of Turner's syndrome using polymorphic DNA probes

Thirty-four families with a child or fetus with Turner's syndrome were studied using a series of polymorphic DNA probes. Analysis of the origin of the normal X chromosome was possible in all cases. In 16 families with 45,X (four fetuses and 12 livebirths), the observed X was maternal in each case, indicating a preferential loss of the paternal sex chromosome at, or before, conception. In the remaining 18 families with a variety of karyotypes, but especially in those where the child had an isochromosome of Xq or a ring X, there was again a strong tendency for the normal X to be maternal. Analysis of parental ages was performed with known origin of each abnormality, but no evidence for an increased or decreased parental age effect was detected.

Association within a family of a balanced autosomal translocation with major mental illness

282 pedigrees in the MRC Cytogenetics Registry, Edinburgh, with familial autosomal anomalies were examined for the presence of associated mental illness. In one large pedigree there were 23 cases of mental and/or behavioural disorders meeting Research Diagnostic Criteria. 34 of the 77 family members available for cytogenetic analysis carried a balanced translocation t(1:11) (q43,q21). Psychiatric diagnoses had been recorded for 16 of the 34 members with the translocation compared with only 5 of the 43 without it. The lod scores (against chance linkage of the translocation with mental illness) were greatest when the mental disorders in the phenotype were restricted to schizophrenia, schizoaffective disorder, recurrent major depression, and adolescent conduct and emotional disorders. Although the mental illness in this family may not be typical of that in the general population, the findings suggest that the q21-22 region of chromosome 11 may be a promising area to examine for genes predisposing to major mental illness.

Karyotyping and identification of human chromosome polymorphisms by single fluorochrome flow cytometry

Frequency distributions of fluorescence intensity of ethidium bromide stained human chromosomes from nine phenotypically normal males are cross correlated and autocorrelated following repeated flow cytometric measurements. It is shown that each individual donor produces a fluorescence profile which is both visually and numerically different from those of other individuals in the set. The wide variety of chromosome heteromorphisms which occur to varying degrees for chromosomes 1, 9, 13, 14, 15, 16, 21, 22 and Y give rise to the uniqueness of a given fluorescence profile. Estimates of chromosome heteromorphisms for each individual in the set were made and then compared with parallel results obtained from inspection of Q-banded and C-banded conventional metaphase preparations. Fluorescence profiles identifiable with each individual were also obtained for Hoechst 33258 stained chromosomes.

Parotid venous ectasia

An unusual recurring mass presented in the parotid region in a young woman. The presentation of the mass was unusual in that it varied with the positioning of the patient's head and with exertional and emotional activity. Prior surgical attempts at cure were unsuccessful. Biplanar subtraction radiographic techniques were used to pinpoint the anatomical problems. This lesion is a vascular anomaly, which requires specific attention to its morphology in order to effect a permanent cure. This case of parotid venous ectasia with its unusual symptom complex was successfully treated, and more than four years have passed without recurrence.

Radiation-induced chromosome aberrations in nuclear-dockyard workers

The incidence of chromosome aberrations in peripheral blood lymphocytes of 197 dockyard workers has been followed over a 10-yr period. These workers were exposed to mixed neutron-gamma radiation during the refuelling of nuclear reactors, but most exposures were below the internationally accepted maximum permissible level of 5 rem per yr. There was a significant increase in chromosome damage with increasing exposure; aberration frequency was a linear function of dose and was unfluenced by age and time of blood sampling after exposure.

Orbitofacial wounds and cerebral artery injuries caused by umbrella tips

Penetrating orbitofacial wounds inflicted by the sharp metal tips of umbrellas may go unrecognized. This type of injury is not generally appreciated as having fatal consequences. Immediate neurologic and radiologic evaluations are diagnostic. The value of computerized tomography and cerebral angiography is stressed.