Relevance of Thymic Stromal Lymphopoietin on the Pathogenesis of Glioblastoma: Role of the Neutrophil

Glioblastoma multiforme (GBM) is the most predominant and malignant primary brain tumor in adults. Thymic stromal lymphopoietin (TSLP), a cytokine primarily generated by activated epithelial cells, has recently garnered attention in cancer research. This study was aimed to elucidate the significance of TSLP in GBM cells and its interplay with the immune system, particularly focused on granulocyte neutrophils. Our results demonstrate that the tumor produces TSLP when stimulated with epidermal growth factor (EGF) in both the U251 cell line and the GBM biopsy (GBM-b). The relevance of the TSLP function was evaluated using a 3D spheroid model. Spheroids exhibited increased diameter, volume, and proliferation. In addition, TSLP promoted the generation of satellites surrounding the main spheroids and inhibited apoptosis in U251 treated with temozolomide (TMZ). Additionally, the co-culture of polymorphonuclear (PMN) cells from healthy donors with the U251 cell line in the presence of TSLP showed a reduction in apoptosis and an increase in IL-8 production. TSLP directly inhibited apoptosis in PMN from GBM patients (PMN-p). Interestingly, the vascular endothelial growth factor (VEGF) production was elevated in PMN-p compared with PMN from healthy donors. Under these conditions, TSLP also increased VEGF production, in PMN from healthy donors. Moreover, TSLP upregulated programed death-ligand 1 (PDL-1) expression in PMN cultured with U251. On the other hand, according to our results, the analysis of RNA-seq datasets from Illumina HiSeq 2000 sequencing platform performed with TIMER2.0 webserver demonstrated that the combination of TSLP with neutrophils decreases the survival of the patient. In conclusion, our results position TSLP as a possible new growth factor in GBM and indicate its modulation of the tumor microenvironment, particularly through its interaction with PMN.

Human Glomerular Endothelial Cells Treated With Shiga Toxin Type 2 Activate γδ T Lymphocytes

The hemolytic uremic syndrome associated with diarrhea, a consequence of Shiga toxin (Stx)-producing Escherichia coli infection, is a common cause of pediatric acute renal failure in Argentina. Stx type 2a (Stx2a) causes direct damage to renal cells and induces local inflammatory responses that involve secretion of inflammatory mediators and the recruitment of innate immune cells. γδ T cells constitute a subset of T lymphocytes, which act as early sensors of cellular stress and infection. They can exert cytotoxicity against infected and transformed cells, and produce cytokines and chemokines. In this study, we investigated the activation of human peripheral γδ T cells in response to the incubation with Stx2a-stimulated human glomerular endothelial cells (HGEC) or their conditioned medium, by analyzing in γδ T lymphocytes, the expression of CD69, CD107a, and perforin, and the production of TNF-α and IFN-γ. In addition, we evaluated by confocal microscopy the contact between γδ T cells and HGEC. This analysis showed an augmentation in cellular interactions in the presence of Stx2a-stimulated HGEC compared to untreated HGEC. Furthermore, we observed an increase in cytokine production and CD107a expression, together with a decrease in intracellular perforin when γδ T cells were incubated with Stx2a-treated HGEC or their conditioned medium. Interestingly, the blocking of TNF-α by Etanercept reversed the changes in the parameters measured in γδ T cells incubated with Stx2a-treated HGEC supernatants. Altogether, our results suggest that soluble factors released by Stx2a-stimulated HGEC modulate the activation of γδ T cells, being TNF-α a key player during this process.

Glioblastoma cells potentiate the induction of the Th1-like profile in phosphoantigen-stimulated γδ T lymphocytes

PURPOSE

γδ T lymphocytes are non-conventional T cells that participate in protective immunity and tumor surveillance. In healthy humans, the main subset of circulating γδ T cells express the TCRVγ9Vδ2. This subset responds to non-peptide prenyl-pyrophosphate antigens such as (E)-4-hydroxy-3-methyl-but-enyl pyrophosphate (HMBPP). This unique feature of Vγ9Vδ2 T cells makes them a candidate for anti-tumor immunotherapy. In this study, we investigated the response of HMBPP-activated Vγ9Vδ2 T lymphocytes to glioblastoma multiforme (GBM) cells.

METHODS

Human purified γδ T cells were stimulated with HMBPP (1 µM) and incubated with GBM cells (U251, U373 and primary GBM cultures) or their conditioned medium. After overnight incubation, expression of CD69 and perforin was evaluated by flow cytometry and cytokines production by ELISA. As well, we performed a meta-analysis of transcriptomic data obtained from The Cancer Genome Atlas.

RESULTS

HMBPP-stimulated γδ T cells cultured with GBM or its conditioned medium increased CD69, intracellular perforin, IFN-γ, and TNF-α production. A meta-analysis of transcriptomic data showed that GBM patients display better overall survival when mRNA TRGV9, the Vγ9 chain-encoding gene, was expressed in high levels. Moreover, its expression was higher in low-grade GBM compared to GBM. Interestingly, there was an association between γδ T cell infiltrates and TNF-α expression in the tumor microenvironment.

CONCLUSION

GBM cells enhanced Th1-like profile differentiation in phosphoantigen-stimulated γδ T cells. Our results reinforce data that have demonstrated the implication of Vγ9Vδ2 T cells in the control of GBM, and this knowledge is fundamental to the development of immunotherapeutic protocols to treat GBM based on γδ T cells.

Risk factors associated with experienced stigma among people diagnosed with mental ill-health: a cross-sectional study

PURPOSE

to examine the relationship between religiosity, social support, trauma, quality of life and experienced stigma of mental illness amongst a population diagnosed with mental ill-health.

METHODS

A cross-sectional survey of day service users in Northern Ireland (n = 295) covering a range of issues including religiosity, social support, quality of life and prior experience of trauma. Stigma was measured using a recognised stigma scale. We used multinomial logistic regression to examine risk factors associated with experienced stigma.

RESULTS

Univariate analysis showed significant associations between stigma and age, number of friends, social support, quality of life and prior experience of trauma. Age, quality of life, and trauma remained independently associated with stigma in a multivariate logistic regression model (x2(12) = 98.40, p < 0.001).

CONCLUSION

Younger people, those with less social support, prior experience of trauma and with poorer quality of life are at increased risk of experiencing stigma related to their diagnosis of mental illness. The findings provide further understanding of stigma and are useful for those overseeing programmes to improve access to mental health treatment.

Unmet need for chronic mental ill health: A population-based record linkage study

Introduction

Many people with chronic mental ill health do not receive the treatment they require, though the true extent of the associated socio-demographic and socio-economic factors is unknown.

Objectives

This unique record linkage study quantifies the characteristics of those reporting chronic poor mental health and the likelihood of being in receipt of pharmacological treatment for those who report chronic mental ill health.

Methods

The Northern Ireland Longitudinal Study (NILS), a random 28% of the 2011 Census returns (aged 25-74), was linked to a population-wide electronic database of prescribed medications. All cohort attributes, including presence of chronic poor mental health were derived from the Census. Logistic regression was used to test the likelihood of people with poor mental health being prescribed psychotropic medication. These findings were compared against similarly derived characteristics of those with respiratory illness on treatment.

Results

Overall, 23,803 (8.3%) of the enumerated 286,717 reported poor mental health and, while 81.5% received pharmacological treatment, those of non-white background (OR=0.38: 95%CI=0.26-0.54), never married (OR=0.67: 95%CI=061-0.73), unemployed (OR=0.65: 95%CI=0.53-0.81) or living in a rural area (OR=0.88: 95%CI=0.79-0.98) were less likely than their respective peers to receive medication for poor mental health. Non-treatment of respiratory illness was less socially patterned.

Conclusions

Some but not all of the observed variation in receipt of psychotropic medicines may represent unmet need. Further studies are required to clarify the patterning of and possible reasons for underuse, including understanding of and attitudes towards healthcare services of groups who are identified as being less likely to receive treatment (for example ethnic minorities and unemployed).

Highlights

Dissimilar molecular and morphological patterns in an introgressed peripheral population of a sand dune species (Armeria pungens, Plumbaginaceae)

Introgression is a poorly understood evolutionary outcome of hybridisation because it may remain largely undetected whenever it involves the transfer of small parts of the genome from one species to another. Aiming to understand the early stages of this process, a putative case from the southernmost border of the Armeria pungens range from its congener A. macrophylla is revisited following the discovery of a subpopulation that does not show phenotypic signs of introgression and resembles typical A. pungens. We analysed morphometrics, nuclear ribosomal DNA ITS and plastid DNA (trnL-trnF) sequences, genome size, 45S and 5S rDNA loci-FISH data and nrDNA IGS sequences. Within the study site, most individuals match morphologies of either of the two hybridising species, particularly the new subpopulation, with intermediate phenotypes being scarce. This pattern does not fully fit molecular evidence revealing two ITS ribotypes co-occurring intragenomically in most plants from the study site and one single plastid haplotype. Genome size and structural features of the IGS sequences both indicate that A. pungens from the study site is genetically more similar to its sympatric congener than to the remainder of its conspecifics. Introgression of A. macrophylla into A. pungens and plastid capture explain all the evidence analysed. However, important features to understand the origin and fate of the introgressed population, such as the degree and direction of introgression, which are important for understanding early stages of hybridisation in plants with low reproductive barriers, should be addressed with new data.

Are Volunteering and Caregiving Associated with Suicide Risk? A Census-based Longitudinal Study

Background

This record linkage study explores the suicide risk of people engaged in caregiving and volunteering. Theory suggests opposing risks as volunteering is associated with better mental health and caregiving with a higher prevalence and incidence of depression.

Methods

A 2011 census-based study of 1,018,000 people aged 25–74 years (130,816 caregivers and 110,467 volunteers; 42,099 engaged in both). All attributes were based on census records. Caregiving was categorised as either light (1–19 hours/week) or more intense (20+ hours/week). Suicide risk was based on 45 months of death records and assessed using Cox proportional hazards models with adjustment for and stratification by mental health status at census.

Results

More intense caregiving was associated with worse mental health (ORadj = 1.15: 95%CI = 1.12, 1.18); volunteering with better mental health (OR 0.87; 95%CIs 0.84, 0.89). The cohort experienced 528 suicides during follow-up. Both volunteering and caregiving were associated with a lower risk of suicide though this was modified by baseline mental ill-health (P = 0.003), HR 0.66; 95%CIs 0.49, 0.88 for those engaged in either activity and with good mental health at baseline and HR 1.02; 95%CIs 0.69, 1.51 for their peers with poor mental health. There was some indication that those engaged in both activities had the lowest suicide risk (HR 0.34; 95%CIs 0.14, 0.84).

Conclusions

Despite the poorer mental health amongst caregivers they are not at increased risk of suicide. The significant overlap between caregiving and volunteering and the lower risk of suicide for those engaged in both activities may indicate a synergism of action.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Do women who intermittently attend breast screening differ from those who attend every invitation and those who never attend?

Objectives

Analysis of screening uptake usually dichotomizes women into attenders and non-attenders, though many women respond positively to some but not all invitations. This paper studies these intermittent attenders.

Methods

A cohort of 8,571 women invited for consecutive breast screens in the Northern Ireland Breast Screening Programme were followed in a study linking screening and census records. Multivariate logistic analysis was used to analyze the characteristics of those who attended both times (consistent), once (intermittent or ‘one-time only’), or not at all (non-attenders).

Results

Overall, 15.5% of women attended once and 13.4% were non-attenders. Non-attenders were characteristically disadvantaged (as measured by social renting, car access, and employment status), less likely to be married, and more likely to be healthy. One-time attenders were younger, and suffering poor health, though there was no association with either social renting or employment status. Privately rented accommodation and city living was associated with both one-time attendance and non-attendance.

Conclusions

One-time attenders are an important and distinct subgroup of screening invitees in this analysis. Their distinct characteristics suggest that transitory factors, such as change in marital status, ill-health, or addressing difficulties through change of residence are important. These distinct characteristics suggest the need for different approaches to increase attendance, among both intermittent attenders and those not attending at all.

Strategies developed and implemented by women's groups to improve mother and infant health and reduce mortality in rural Malawi

We evaluated the strategies to tackle maternal and infant health problems developed by women's groups in rural Malawi. Quantitative data were analyzed on strategies developed by 184 groups at two of the meetings in the community action cycle (attended by 3365 and 3047 women). Data on strategies implemented was collected through a survey of the 197 groups active in January 2010. Qualitative data on the identification and implementation of strategies was collected through 17 focus group discussions and 12 interviews with men and women. To address the maternal and child health problems identified the five most common strategies identified were: health education sessions, bicycle ambulances, training of traditional birth attendants, wetland vegetable garden (dimba garden) cultivation and distribution of insecticide treated bednets (ITNs). The five most common strategies actually implemented were: dimba garden cultivation, health education sessions, ITN distribution, health programme radio listening clubs and clearing house surroundings. The rationale behind the strategies and the factors facilitating and hindering implementation are presented. The potential impact of the strategies on health is discussed. Women's groups help communities to take control of their health issues and have the potential to reduce neonatal, infant and maternal mortality and morbidity in the longer term.

The low uptake of breast screening in cities is a major public health issue and may be due to organisational factors: a Census-based record linkage study

BACKGROUND

Cancer screening uptake is generally lower in UK cities but quantifying city-level effects from causes due to population composition that comprise cities is hampered by data limitations.

METHODS

A unique data linkage project combining a 2001 Census-based longitudinal study in Northern Ireland with the NHS Breast Screening Program. Validated uptake in the three years following the Census for Belfast Metropolitan Urban Area was compared against the rest of the country with adjustment for cohort attributes defined at Census.

RESULTS

Belfast Metropolitan Urban Area contained 34.8% of invited women but a greater proportion who rented their accommodation (40.3%) or who did not have a car (47.1%). After full adjustment for demographic and socio-economic factors, Belfast Metropolitan Urban Area uptake was lower for first and subsequent screen (Odds ratio (OR) 0.72; 95% CIs 0.66, 0.78 and OR 0.58; 95% CIs 0.55, 0.62 respectively). There were no significant interactions between patient characteristics and area of residence indicating that all residents in Belfast Metropolitan Urban Area are equally affected.

CONCLUSION

The reduced uptake of screening in cities is a major public health issue; the effects are large and a large proportion of the population are affected, organisational factors appear to be the primary cause. Strategies to correct this imbalance might help reduce inequalities in health.

Women's groups' perceptions of neonatal and infant health problems in rural Malawi

AIMS

To present the perceptions of women in rural Malawi regarding the health problems affecting neonates and infants and to explore the relevance of these perceptions for child health policy and strategy in Malawi.

METHODS

Women's groups in Mchinji district identified newborn and infant health problems (204 groups, 3484 women), prioritised problems they considered most important (204 groups, 3338 women) and recorded these problems on monitoring forms. Qualitative data was obtained through 6 focus-group discussions with the women's groups and 22 interviews with individuals living in women's group communities but not attending groups.

RESULTS

Women in Malawi do not define the neonatal period according to any epidemiological definition. In order of importance they identified and prioritised the following problems for newborns and infants: diarrhoea, infection, preterm birth, tetanus, malaria, asphyxia, respiratory tract infection, hypothermia, jaundice, convulsions and malnutrition.

CONCLUSION

This study suggests that women in rural Malawi collectively have a developed understanding of neonatal and infant health problems. This makes a strong argument for the involvement of lay people in policy and strategy development and also suggests that this capacity, harnessed and strengthened through community mobilisation approaches, has the potential to improve neonatal and infant health and reduce mortality.

AIDS mortality in African migrants living in Portugal: evidence of large social inequalities

OBJECTIVE

To examine infectious disease and AIDS mortality among African migrants in Portugal, gender and socio-economic differences in AIDS mortality risk, and differences between African migrants to Portugal and to England and Wales.

METHODS

Data from death registrations, 1998-2002, and the 2001 Census were used to derive standardised death rates by country of birth, occupational class (men only), and marital status.

RESULTS

Compared with people born in Portugal, African migrants had higher mortality for infectious diseases including AIDS. There was considerable heterogeneity among Africans, with those from Cape Verde having the highest mortality. Death rates were more than five times higher among those who were unmarried than those who were. A larger proportion of Africans were unmarried accounting for some excess mortality. Death rates were also higher among men from manual occupational classes than among men from non-manual. A comparison with England and Wales shows that death rates for infectious disease and AIDS in Portugal are much higher and Africans in Portugal also fare worse than Africans in England and Wales.

CONCLUSION

AIDS mortality rates were higher among Africans than those born in Portugal and were associated with socio-environmental factors. Further research is required to interpret the excess mortality among Africans and there is a need to ensure the inclusion of relevant data items on ethnicity in national monitoring and surveillance systems.

Meiotic behavior and DNA content in alloplasmic lines of maize

The cytoplasm of Zea mays ssp. mexicana (teosinte) affects several inherited traits when combined with genotypes of maize (Zea mays ssp. mays). The meiotic behavior and the total DNA content of four lines of maize with teosinte cytoplasm were compared with those of the parental lines. The results obtained suggest that the cytoplasm of teosinte promotes an increase in total nuclear DNA content, perhaps through an increase of highly repetitive DNA in the knob zones. The analysis of meiotic behavior indicates that the cytoplasm of teosinte can alter the spatial distribution of the genomes, since two groups of five bivalents each were observed at a high frequency. During prophase I - anaphase I, each group of five bivalents behaves in a slightly asynchronous way with respect to the other group and, moreover, two nucleoli were observed in 10% of the cells. These results suggest that the cytoplasm of teosinte could induce changes affecting genomic structure and function in some maize genotypes. These changes are of potential importance for breeding programs and evolutionary studies.

Meiotic loss of the B chromosomes of maize is influenced by the B univalent co-orientation and the TR-1 knob constitution of the A chromosomes

The suppression of meiotic loss when the maize B chromosomes are unpaired is genetically determined. Two genotypes were selected in 1B x 0B crosses: the H line where the B transmission rate is Mendelian (50%) and the L line where the B is present in only about 40% of the progeny. Using the ZmBs probe located at the centromere and at the distal portion of the B chromosome in FISH, we found that the centromeric and telomeric ends of the B univalent co-orient at metaphase I. This feature seems to promote proper centromere orientation causing the lack of meiotic loss of the unpaired B. The co-orientation was observed in both lines, however in the L line the B univalents were not always properly oriented, showing amphitelic orientation in about 25% of the metaphase I cells. We also studied plants of the H and L lines with FISH to test the possible relation between the knob constitution and B loss. It has been found that the plants of both lines are similarly variable for the 180-bp knob repeat, but they differ in the TR-1 350-bp repeat, the L line having more TR-1 knobs. The use of a 45S rDNA probe which labels chromosome 6, allowed us to determine that this chromosome shows the main variability between the two lines: the L line has TR-1 in both arms, showing a large TR-1 knob on the long arm. The H line has only one, generally located on the short arm besides the NOR.

Trends for coronary heart disease and stroke mortality among migrants in England and Wales, 1979-2003: slow declines notable for some groups

Objective:

To examine trends in coronary heart disease and stroke mortality in migrants to England and Wales.

Design:

Cross-sectional.

Outcome measures:

Age-standardised and sex-specific death rates and rate ratios 1979–83, 1989–93 and 1999–2003.

Results:

Coronary mortality fell among migrants, more so in the second decade than the first. Rate ratios for coronary mortality remained higher for men and women from Scotland, Northern Ireland, Republic of Ireland and South Asia, and lower for men from Jamaica, other Caribbean countries, West Africa, Italy and Spain. Rate ratios increased for men from Jamaica (1979–83: 0.45, 0.40 to 0.50; 1999–2003: 0.81, 0.73 to 0.90), Pakistan (1979–83: 1.14, 1.04 to 1.25; 1999–2003: 1.93, 1.81 to 2.06), Bangladesh (1979–83: 1.36, 1.15 to 1.60; 1999–2003: 2.11, 1.90 to 2.34), Republic of Ireland (1979–1983: 1.18, 1.15 to 1.21; 1999–2003: 1.45, 1.39 to 1.52) and Poland (1979–83: 1.17, 1.09 to 1.25; 1999–2003: 1.97, 1.57 to 2.47), and for women from Jamaica (1979–83: 0.63, 0.52 to 0.77; 1999–2003: 1.23, 1.06 to 1.42) and Pakistan (1979–83: 1.14, 0.88 to 1.47; 1999–2003: 2.45, 2.19 to 2.74), owing to smaller declines in death rates than those born in England and Wales. Rate ratios for stroke mortality remained higher for migrants. As a result of smaller declines, rate ratios increased for men from Pakistan (1979–1983: 0.99, 0.76 to 1.29; 1999–2003: 1.58, 1.35 to 1.85), Scotland (1979–1983: 1.11, 1.04 to 1.19; 1999–2003: 1.30, 1.19 to 1.42) and Republic of Ireland (1979–1983: 1.27, 1.19 to 1.36; 1999–2003: 1.67, 1.52 to 1.84).

Conclusion:

For groups with higher mortality than people born in England and Wales, mortality remained higher. Smaller declines led to increasing disparities for some groups and to excess coronary mortality for women from Jamaica. Maximising the coverage of prevention and treatment programmes is critical.

FISH detection of ribosomal cistrons and assortment-distortion for X and B chromosomes in Dichroplus pratensis (Acrididae)

Assortment-distortion with respect to the X and NOR activity of a rare mitotically stable B chromosome (B(N)), was examined in 16 males of Dichroplus pratensis (Acrididae: Melanoplinae) from Argentine populations. In 1B individuals, the X and B associate preferentially during prophase I reaching a maximum level of association at zygotene. Frequency of X/B association remains relatively high up to diplotene-diakinesis and decreases steeply towards metaphase I. The percent X/B association at each stage is positively influenced by association at the previous stage, and interindividual variability in X/B association decreases as the frequency of association increases. Both chromosomes tended to preferentially orientate toward the same pole at MI (mean ratio of 16 individuals, 1.50:1) which determined an excess of XB and 00 second spermatocytes over X0 and 0B ones (1.39:1). No significant differences occurred between the MI, AI and MII assortment ratios. Fluorescent in situ hybridisation (FISH) confirmed that the B chromosome carries ribosomal genes and helped to establish that, during spermiogenesis, both the B and the normal NOR-bearing chromosome (S8) are clustered near the centriole adjunct region of spermatids. However, FISH failed to reveal the existence of inactive ribosomal cistrons in the X chromosome, as previously suggested, thus providing no support to a simple origin of the B from the X.

The parasitic effects of rye B chromosomes might be beneficial in the long term

Rye B chromosomes (Bs) have strong parasitic effects on fertility. B carrying plants are less fertile than 0B ones, whereas the Bs have no significant effects on plant vigour. On the other hand, it has been reported that B transmission is under genetic control in such a way that H line plants transmit the Bs at high frequency, whereas the Bs in the low B transmission rate line (L) fail to pair at metaphase I and are frequently lost. In the present work we analyse variables affecting vigour and fertility considering not only the number of Bs of each plant, but also its H or L status and the B number of its maternal parent. Our results show that the Bs not only decrease female fertility of the B carrier, but the fertility of its progeny, with the exception of 0B plants coming from a 4B mother, which are the most fertile. In this way B chromosomes can be considered as a selective factor. Pollen abortion was higher in B carriers, in the progeny of B carriers and in H plants, but 4B plants coming from B carrying mothers produce less aborted pollen, indicating that a high B number is more deleterious if it is transmitted in the pollen grains. A similar result was obtained for endosperm quality estimated as grain weight, because it is negatively influenced by the Bs in 4B plants coming from a 0B mother. H plants were always less fertile than L ones, indicating that alleles increasing the loss of Bs in the L line will be probably selected as a defence of the A genome against the invasive Bs of the H line. Flower number is not affected by the Bs.

Mycobacterium tuberculosis isolates belonging to katG gyrA group 2 are associated with clustered cases of tuberculosis in Italian patients

Fifty-one consecutive isolates of Mycobacterium tuberculosis, collected during a 2-year period in the north-east of Italy, were subjected to IS6110-RFLP analysis to detect the presence of clusters and assigned to one of the three genotypic groups delineated by single nucleotide polymorphisms in the genes katG and gyrA. All the isolates collected from the local population belonged to group 2 or 3, while group 1 isolates were found only in specimens collected from African immigrants. Clustered cases of tuberculosis, which are likely to be related to recently transmitted infection, were found to be significantly associated with katG gyrA group 2. In the local situation, strains belonging to this group may therefore present a higher risk of transmission.

One gene determines maize B chromosome accumulation by preferential fertilisation; another gene(s) determines their meiotic loss

Genotypes of high (H(m)) and low (L(m)) male B transmission rate (B-TR) were obtained. B-TR segregation in the F2 is reported, showing that the H(m) and L(m) lines differ in a single locus we call mBt (male B transmission), controlling B preferential fertilisation in maize. The egg cells control which one of the sperm nuclei is going to fertilise them, mBt(h) egg cells being preferentially fertilised by the sperm nucleus carrying the supernumerary B chromosomes (Bs). It is hypothesised that the mBt gene is involved in the normal fertilisation of maize but the parasitic Bs take advantage of the mBt(h) allele to increase their own transmission. Selection was also carried out when the Bs were transmitted on the female side (H(f) and L(f) lines). The F1 hybrids show that the gene(s) that we call fBt (female B transmission), controlling female B-TR, is located on the A chromosomes acting at diploid level, the fBt(l) allele(s) for low transmission being dominant. This allele causes the loss of Bs at meiosis, which is shown using a specific B molecular probe to determine B presence/absence in microspores of both lines and hybrids. Maize Bs are a nice example of intragenome conflict, because the mBt and fBt loci are a polymorphic system of attack and defence between A and B chromosomes.

Is maize B chromosome preferential fertilization controlled by a single gene?

In previous work, genotypes for high and low B chromosome transmission rate were selected from a native race of maize. It was demonstrated that the B transmission is genetically controlled. The present work reports the fourth and fifth generations of selection and the F1 hybrids between the lines. The native B is characterized by a constant behaviour, with normal meiosis and nondisjunction in 100% of postmeiotic mitosis. It is concluded that genetic variation for B transmission between the selected lines is due to the preferential fertilization process. The F1 hybrids show intermediate B transmission rate between the lines. They are uniform, the variance of the selected character being one order of magnitude lower than that of the native population. In addition, 0B x 2B and 2B x 2B crosses were made to study the effect of the presence of B chromosomes in the female parent, resulting in non-significant differences. Several crosses were made both in Buenos Aires and in Madrid to compare the possible environmental effect, but significant differences were not found. Our results are consistent with the hypothesis of a single major gene controlling B transmission rate in maize, which acts in the egg cell at the haploid level during fertilization. It is also hypothesized that maize Bs use the normal maize fertilization process to promote their own transmission.

Chromosome nondisjunction and instabilities in tapetal cells are affected by B chromosomes in maize

Abnormal mitosis occurs in maize tapetum, producing binucleate cells that later disintegrate, following a pattern of programmed cell death. FISH allowed us to observe chromosome nondisjunction and micronucleus formation in binucleate cells, using DNA probes specific to B chromosomes (B's), knobbed chromosomes, and the chromosome 6 (NOR) of maize. All chromosome types seem to be involved in micronucleus formation, but the B's form more micronuclei than do knobbed chromosomes and knobbed chromosomes form more than do chromosomes without knobs. Micronuclei were more frequent in 1B plants and in a genotype selected for low B transmission rate. Nondisjunction was observed in all types of FISH-labeled chromosomes. In addition, unlabeled bridges and delayed chromatids were observed in the last telophase before binucleate cell formation, suggesting that nondisjunction might occur in all chromosomes of the maize complement. B nondisjunction is known to occur in the second pollen mitosis and in the endosperm, but it was not previously reported in other tissues. This is also a new report of nondisjunction of chromosomes of the normal set (A's) in tapetal cells. Our results support the conclusion that nondisjunction and micronucleus formation are regular events in the process of the tapetal cell death program, but B's strongly increase A chromosome instability.

Risk of mortality, cancer incidence, and stroke in a population potentially exposed to cadmium

OBJECTIVES

To follow up mortality and cancer incidence in a cohort potentially exposed to cadmium and to perform a geographical (ecological) analysis to further assess the health effects of potential exposure to cadmium.

METHODS

The English village of Shipham has very high concentrations of cadmium in the soil. A previous cohort study of residents of Shipham in 1939 showed overall mortality below that expected, but a 40% excess of mortality from stroke. This study extends the follow up of the cohort for mortality to 1997, and includes an analysis of cancer incidence from 1971 to 1992, and a geographical study of mortality and cancer incidence. Standardised mortality and incidence ratios (SMRs and SIRs) were estimated with regional reference rates. Comparisons were made with the nearby village of Hutton.

RESULTS

All cause cohort mortality was lower than expected in both villages, although there was excess cancer incidence in both Shipham (SIR 167, 95% confidence interval (95% CI) 106 to 250) and Hutton (SIR 167, 95% CI 105 to 253). There was an excess of mortality from hypertension, cerebrovascular disease, and nephritis and nephrosis, of borderline significance, in Shipham (SMR 128, 95% CI 99 to 162). In the geographical study, all cause mortality in Shipham was also lower than expected (SMR 84, 95% CI 71 to 100). There was an excess in genitourinary cancers in both Shipham (SIR 160, 95% CI 107 to 239) and Hutton (SIR 153, 95% CI 122 to 192).

CONCLUSION

No clear evidence of health effects from possible exposure to cadmium in Shipham was found despite the extremely high concentrations of cadmium in the soil.

Intimal-medial thickness of the common carotid arteries and lower limbs atherosclerosis in the elderly

BACKGROUND

In the present study, the authors consider the possible association between intimal-media thickness of the common carotid arteries and lower limb atherosclerosis, in a group of elderly patients; the authors also consider the presence of cardiovascular risk factors.

METHODS

B-mode ultrasound measurement of the intimal-media thickness of the common carotid arteries was performed on 80 subjects. Lower limbs atherosclerosis was defined as the presence of intermittens claudicatio and/or ankle-arm index < 0.9. Baseline clinic examination and blood tests were performed in all subjects to consider the presence of cardiovascular risk factors. Linear regression analysis was used to assess the linear relationship between intimal-media thickness of the common carotid arteries and lower limb atherosclerosis.

RESULTS

Linear regression analysis showed a statistical association between increased values of intimal-media thickness of the common carotid arteries and lower limb atherosclerosis. Sixty-four (80%) subjects presented one or more associated cardiovascular risk factors.

CONCLUSIONS

The results of the the present study confirm that intimal-media thickness of the common carotid arteries is a marker for the identification of generalized atherosclerosis and may be useful for the identification of subjects, even at early stages, at risk of cardiovascular diseases.

Cancer incidence among first generation Scottish, Irish, West Indian and South Asian migrants living in England and Wales

OBJECTIVES

To examine the incidence of cancers among persons born in Scotland, Northern Ireland, the Irish Republic, Caribbean Commonwealth and Indian subcontinent and living in England and Wales.

METHODS

Longitudinal Study of 1% of population of England and Wales followed from 1971 to 1989. Standardised incidence ratios (SIRs) were derived for commonly occurring cancers and all cancers using the age-sex-specific rates for all females and all males in the Longitudinal Study.

RESULTS

The incidence of all malignant neoplasms among West Indians (females SIR = 67, male SIR = 70) and Indians (female SIR = 32, male SIR = 52) was low. Among South Asians, this pattern was consistent for Hindus, Sikhs and Moslems. Scottish females showed raised incidence of lung cancer (SIR = 149) and those from the Irish Republic of oral cavity and pharynx (SIR = 321), oesophageal (SIR = 219) and liver (SIR = 373) cancers. Among Northern Irish females, incidence of lung cancer (SIR = 193) was raised. West Indian and South Asian females showed low incidence of breast cancer (SIR = 55 and 45, respectively). High incidence of laryngeal (SIR = 229) and renal (SIR = 203) cancers was observed for Scottish males and of oral cancer (SIR = 259) for males from the Irish Republic. At ages 15-64, raised incidence of prostate cancer (SIR = 129) and of leukaemia (SIR = 252) was also observed for men from the Irish Republic. Northern Irish males showed raised incidence of stomach cancer (SIR = 200).

CONCLUSION

This study describes patterns of cancer incidence among migrant groups, most of which reflect environmental influences. This has challenging implications for sensitive targeting of primary interventions. It is important not to be complacent about lower risks of main cancers among West Indians and South Asians. In all Longitudinal Study members, breast cancer was the most common malignancy among females and lung cancer among males. This was also true for all migrant groups with the exception of Northern Irish women for whom lung cancer was the most common.

Longitudinal study of socio-economic differences in the incidence of stomach, colorectal and pancreatic cancers

Using the ONS Longitudinal Study, the incidence of stomach, colorectal and pancreatic cancers from 1976-90 was examined for men and women aged 30 years and over by their housing tenure and occupational social class. Large socio-economic differences in the incidence of stomach cancer for both men and women were found. The pattern of colorectal cancer was less clear, with women in more advantaged social groups experiencing higher incidence while for men there was no significant association. Pancreatic cancer showed no association with socio-economic status. Consistent findings with each indicator strengthen the interpretation of the results. Risk factors for these cancers are known to vary by socio-economic status, and this study demonstrates the importance of continued monitoring of the distribution of cancer incidence.

Does social mobility affect the size of the socioeconomic mortality differential?: evidence from the Office for National Statistics Longitudinal Study

"The effect of social mobility on the socioeconomic differential in mortality is examined with data from the Office for National Statistics Longitudinal Study. The analyses involve 46,980 men aged 45-64 years in 1981. The mortality risk of the socially mobile is compared with the mortality risk of the socially stable after adjustment for their class of origin (their social class in 1971) and class of destination (their social class in 1981) separately. Among those in employment there is some evidence that movement out of their class of origin is in the direction predicted by the idea of health-related social mobility. This evidence, however, seems strongest for causes of death which are least likely to have been preceded by prolonged incapacity. Movement into the class of destination, however, shows the opposite relationship with mortality."

Localization of the genes controlling B chromosome transmission rate in maize (Zea mays ssp. mays, Poaceae)

In previous papers we found that the frequency of B chromosomes in native races of maize varies considerably in different populations. Moreover, we found genotypes that control high and low transmission rates (TR) of B chromosomes in the Pisingallo race. In the present work crosses were made to determine whether the genes controlling B-TR are located on the normal chromosome set (As) or on the B chromosomes (Bs). We made female f.0B × male m.2B crosses between and within high (H) and low (L) B-TR groups. The Bs were transmitted on the male side in all cases. The mean B-TR from the progeny of f.0B (H) × m.2B (H) and f.0B (H) × m.2B (L) crosses was significantly higher than that from f.0B (L) × m.2B (L) and f.0B (L) × m.2B (H) crosses. The results show that the B-TR of the crosses corresponds to the H or L B-TR of the 0B female parents irrespective of the Bs of the male parent. This indicates that B-TR is genetically controlled by the 0B female parent and that these genes are located on the A chromosomes.

Teenage mothers and the health of their children

Teenage mothers continue to present challenges to social policy and remain of topical interest to the media. This article discusses trends in teenage conception rates, their outcomes and long term consequences. In 1996, 7 per cent of all births were to girls aged under 20. On average children born to teenage girls have lower birthweights, increased risk of infant mortality and an increased risk of some congenital anomalies. They are less likely to be breastfed and more likely to live in deprived circumstances. These factors in turn influence their health and long term opportunities.

[Stenosis of the internal carotid arteries and cardiovascular risk factors in a group of patients aged 65 years and over]

BACKGROUND

In the present study, the degree of stenosis of internal carotid arteries and the presence of cardiovascular risk factors are examined.

METHODS

Two hundred patients underwent high resolution B-mode echotomography of the carotid arteries; furthermore, the presence of associated cardiovascular risk factors was considered.

RESULTS

Small stenosis (< 16%) were reported in 113 (56.5%) patients; moderate stenosis (16-49%) were reported in 58 (29%) patients; severe stenosis (50-79%) were reported in 19 (9.5%) patients; subocclusive stenosis (80-99%) were reported in 2 (1%) patients; occlusions were reported in 8 (4%) patients. One hundred and fifty patients (75%) presented one or more associated cardiovascular risk factors. Hypertension was present in 122 (61%) patients; hypercholesterolemia in 43 (21.5%) patients; diabetes mellitus in 41 (20.5%) patients; 26 (13%) patients were smokers.

CONCLUSIONS

According to other studies, stenosis < 50% were the most frequent (85.5%) in the subjects examined. Stenosis > or = 50% were more frequent in males than females. Hypertension was the most frequent associated cardiovascular risk factor; therefore the degree of stenosis increased with the increasing number of cardiovascular risk factors.

Incidence of health of the nation cancers by social class

Using data from the Longitudinal Study social class patterns in the incidence of breast, lung and cervical cancer in women, and lung cancer in men, for the period 1976-89 were examined. At working ages, 15 to 64, there was very little difference in breast cancer incidence between women in non-manual and manual classes. At older ages the incidence was higher in women in non-manual classes than in those in manual classes. Cervical cancer incidence was considerably higher among younger women in manual than in non-manual classes and these differences were greatest in 1986-89. Among both younger and older men and women, strong class differentials in the incidence of lung cancer were evident in 1986-89. These findings indicate the need to target prevention strategies sensitively and to ensure equitable access to services.

Genome size and numerical polymorphism for the B chromosome in races of maize (Zea mays ssp. mays, Poaceae)

Twenty-one native populations (1120 individuals) of maize from Northern Argentina were studied. These populations, which belong to 13 native races, were cultivated at different altitudes (80-3620 m). Nineteen of the populations analyzed showed B chromosome (Bs) numerical polymorphism. The frequency of individuals with Bs varied from 0 to 94%. The number of Bs per plant varied from 0 to 8 Bs, with the predominant doses being 0, 1, 2, and 3. Those populations with varying number of Bs showed a positive and statistically significant correlation of mean number of Bs with altitude. The DNA content, in plants without Bs (A-DNA)(2n = 20), of 17 populations of the 21 studied was determined. A 36% variation (5.0-6.8 pg) in A-DNA content was found. A significant negative correlation between A-DNA content and altitude of cultivation and between A-DNA content and mean number of Bs was found. This indicates that there is a close interrelationship between the DNA content of A chromosomes and doses of Bs. These results suggest that there is a maximum limit to the mass of nuclear DNA so that Bs are tolerated as long as this maximum limit is not exceeded.

Research implications of improvements in access to the ONS Longitudinal Study

In this article we outline significant changes in the way the ONS Longitudinal Study data are stored, accessed and analysed. The data were held previously on mainframe computers. Recent technological changes have made it possible to introduce PC-based systems without compromising confidentiality. The advantages of this new computing environment are illustrated with recent findings on geographic inequalities in health.

Maltose chemotaxis involves residues in the N-terminal and C-terminal domains on the same face of maltose-binding protein

The periplasmic maltose-binding protein (MBP) of Escherichia coli is the recognition component of the maltose chemoreceptor and of the active transport system for maltose. It interacts with the Tar chemotactic signal transducer and the integral cytoplasmic-membrane components (the MalF and MalG proteins) of the maltose transport system. Maltose binds in a cleft between the globular N-terminal and C-terminal domains of MBP, which are connected by a moveable hinge. The two domains undergo a large motion relative to one another as the protein moves from the open, unbound state to the closed, ligand-bound state. We generated, by doped-primer mutagenesis, amino acid substitutions that specifically disrupt the chemotactic function of MBP. These substitutions cluster in two well-defined regions that are nearly contiguous on the surface of MBP in its closed conformation. One region is in the N-terminal domain and one is in the C-terminal domain. The distance between the two regions is expected to change substantially as the protein goes from the open to the closed form. These results support a model in which ligand binding brings two recognition sites on MBP into the proper spatial relationship to interact with complementary sites on Tar. Mutations in MBP that appear to cause defects in interaction with MalF and MalG are distributed differently from mutations that primarily affect maltose taxis. We conclude that the regions of MBP that contact Tar and those that contact MalF and MalG are adjacent on the face of the protein opposite the hinge connecting the two domains and that those regions are largely, although perhaps not entirely, distinct.

The mortality of first and second generation Irish immigrants in the U.K

The Irish have generally been ignored in studies of the health needs of ethnic groups in the U.K. despite being the largest immigrant group and having the highest Standardised Mortality Ratio of all first generation immigrants. Using the OPCS Longitudinal Study, the present paper shows that this excess mortality persists into the second generation Irish in the U.K., regardless of the part of Ireland from which their parents originated or whether one or both parents were Irish. The effects of social class, age, sex, year of entry to the U.K. and period of death are explored, and variations with these factors are found to be complex.