Underreporting of AIDS cases in Canada: a record linkage study.

To estimate the rate of underreporting of AIDS (acquired immune deficiency syndrome) to the Federal Centre for AIDS (FCA), in 1988 the initials, date of birth and place of residence of 66 patients with AIDS known to the Toronto Sexual Contact Study (TSCS), 65 patients with AIDS known to the Vancouver Lymphadenopathy-AIDS Study (VLAS) and other participants in both studies who did not have AIDS were sent to the Bureau of Epidemiology and Surveillance, FCA. The FCA conducted a manual record linkage to link these data to the national registry of reported cases. The rate of underreporting was 12% (8/65) for the VLAS and 18% (12/66) for the TSCS. The specific diagnosis was not related to the rate of underreporting. For the TSCS the rate of underreporting had increased from 0% in 1983-84 to 44% in 1987-88 (p = 0.001). Differences in the observed rates of underreporting between the two studies are likely the result of differences in the reporting responsibilities of physicians involved in the studies.     

Migration and fertility behaviour in England and Wales: a record linkage study

Relationships between migration and fertility are examined using data from the OPCS Longitudinal Study of England and Wales, including linked information from the 1971 and 1981 censuses and birth registration data for the period 1971-80. The results show that the proportion moving between the 1971 Census and the 1st subsequent birth was higher among tenants than owner occupiers, particularly for women in shared accommodation in 1971. The association between tenure and moving was more consistent than the relationship between moving and the husband's social class. Differences in the proportions moving between the censuses were positively associated with fertility in the same period particularly for women in potentially crowded accomodation in 1971. Moving in 1970-1971 was not associated with differences in parity progression ratios 1971-1981. There were however, differences in the timing of births, suggesting that long distance migration was associated with a postponement of the 1st or 2nd child, probably because both longer distance migration and fertility behavior are associated with other characteristics such as education.     

The East Flanders Prospective Twin Survey (Belgium): a population-based register.

The East Flanders Prospective Twin Survey (EFPTS), started in 1964, is unique among the 17 major European twin registers because it is population based, the twins (and higher order births) are ascertained at birth, basic perinatal data are collected, chorion type is established and, when appropriate, genetic markers including DNA fingerprints, are determined. The total number of sets is 5089 twin, 158 triplet and 14 of higher order. Zygosity has been diagnosed on the basis of sex, placental structure and genetic markers in more than 95% of pairs. The EFPTS is the only large register that includes placental data and allows differentiation of three subtypes of monozygotic twins based on the time of the initial zygotic division: the dichorionic-diamnionic pairs (early), the monochorionic-diamnionic pairs (intermediate), and the monochorionic-monoamnionic pairs (late). Methodology and basic results in twins are considered in this article; detailed studies will be reported later. The sex proportion in dizygotic (DZ) twins is the same as in singletons, whereas monozygotic (MZ) twins number more girls than boys. The difference in perinatal mortality between DZ and MZ twins is limited to the monochorionic MZ subgroup. Birth weight is highest in DZ twins and diminishes stepwise in MZ dichorionic and MZ monochorionic twins. Duration of pregnancy follows the same trend but is limited to a few days. Iatrogenic pregnancies are increasing to the point of representing almost 50% of the twin births in 1997.     

Cervical cancer screening in Middle Eastern and Asian migrants to Australia: A record linkage study

Background. Australia's organized cervical screening program recommends two-yearly screening for women aged 18–69 years and reminder letters are sent at 27 months. Cervical screening registers hold comprehensive information on screening, but not country of birth. A linkage study was performed in order to assess cervical screening behavior in migrants. Methods. To assess screening participation, we linked year 2000 records for 12,541 Middle Eastern/Asian-born women 20–54 years of age, and an age and area matched random sample of 12,143 Australian-born women in the New South Wales (NSW) Midwives Data Collection (MDC), which records country of birth, to screening register records. Screening behavior after 2000 was assessed in women without a recorded prior cervical abnormality. Results. The odds ratios for being screened at least once within a 3 year period, with reference to Australian-born women and adjusted for age, parity, socioeconomic status and smoking, were 0.88 (95% CI: 0.81–0.97) and 0.74 (95% CI: 0.70–0.79) in women born in the Middle East and Asia, respectively. Screening increased with increasing socioeconomic status (SES), absence of smoking and greater parity in Australian-born women but little, if at all, in migrant women. In a sensitivity analysis in which hospital admitted patients were the source of population samples, some patterns were sufficiently different to suggest that selection for illness can affect the strength and direction of associations in linked data. Conclusion. Migrant women from Asian and Middle-eastern countries are less likely than Australian-born women to participate in cervical screening at the recommended interval. Their likelihood of screening is also less related to socioeconomic status, smoking and parity than that in Australian-born women.     

T-cell receptor genes and insulin-dependent diabetes mellitus (IDDM): no evidence for linkage from affected sib pairs.

Several investigators have reported an association between insulin-dependent diabetes mellitus (IDDM) and an RFLP detected with a probe for the constant region of the beta chain (C beta) of the human T-cell receptor (TCR). A likely hypothesis is that the closely linked TCR variable (V beta) region genes contribute to IDDM susceptibility and that the association with the TCR C beta locus reflects this contribution, via linkage disequilibrium between V beta and C beta. The products of the beta-chain genes might be expected to be involved in the etiology of IDDM because of the autoimmune aspects of IDDM, the known involvement of HLA, and the necessity for TCR and HLA molecules to interact in an immune response. In order to investigate the hypothesis, we tested for linkage between IDDM and V genes encoded at either the TCR beta locus on chromosome 7 or the TCR alpha locus on chromosome 14, using 36 families with multiple affected sibs. No excess sharing of haplotypes defined by V alpha or V beta gene RFLPs was observed in affected sib pairs from IDDM families. We also studied unrelated IDDM patients (N = 73) and controls (N = 45) with the C beta RFLP but were unable to confirm the reported association even when the sample was stratified by HLA-DR type. Our results are incompatible with close linkage, in the majority of families, between either the TCR alpha or TCR beta locus and a gene making a major contribution to susceptibility to IDDM.     

Seasonal changes in a population of Sacculina carcini Thompson (Crustacea: Rhizocephala) in Scotland

On the basis of studies of seasonal changes in the infection levels of Sacculina carcini in Carcinus maenas a life history for Sacculina at Millport, Scotland is proposed. This life history differs from that proposed by Foxon (1940) in that the externa is considered only to live for one year, the interna subsequently regenerating a new externa. This life cycle receives support from observations on regenerating externa.     

Comparative study of two largely infilled estuaries: The Eden Estuary (Scotland) and the Ria de Foz (Spain)

Two small estuaries, the Eden Estuary of eastern Scotland and the Ria de Foz of north west Spain, are compared. The former was glaciated during the Pleistocene, the latter was not. These water bodies are macrotidal, of similar size, entrance morphology and advanced state of sedimentary infill. There are, however, major differences in their sedimentary dynamics partly as a result of anthropogenic interference. A training wall partially confines the main channel of the Ria de Foz, whereas the Eden Estuary lacks comparable structures. Prior to the extension of the Foz wall, the rate of migration of a spit at the mouth of the ria was up to one order of magnitude greater than that of a similar spit in the Eden Estuary. Following completion of the wall, the rate of spit erosion in the Ria de Foz increased to two orders of magnitude greater than that of natural processes in the Eden. A beach nourishment scheme at Foz, relocating sediment deposited within the Ria, has succeeded in stabilising the spit and substantially reducing erosion. Relative stability of land and sea may have existed over the last 5,000 years at Foz but not at the mouth of the Eden, where isostatic uplift has exceeded sea level rise. The requisite stability for complete sedimentary infill at Foz may not exist owing to the predicted worldwide rise of sea level due to global warming. The rise of sea and land levels around the Eden Estuary are now believed to be counterbalanced, providing the necessary geological conditions for complete sedimentary infill.     

The first record and occurrence of Stagnicola turricula (Held, 1836) (Gastropoda: Pulmonata: Lymnaeidae) in Upper Silesia (Southern Poland) in relation to different environmental factors

The degradation of freshwater environments, e.g.: eutrophication, drainage, water pollution, has led to the decline of lymnaeid species distribution. Some of them are recorded in the Red Book and Red List of species as rare, vulnerable or legally protected. The survey was carried out in Upper Silesia (Southern Poland), which is one of the biggest coal basins in the world. This region is devoid of natural water bodies; only reservoirs of an anthropogenic origin are common. Anthropogenic reservoirs, which are not very degraded, constitute important lentic habitats in Upper Silesia and they provide refuges for wildlife including rare and vulnerable molluscan species. This survey uncovered the first occurrence of Stagnicola turricula in the anthropogenic reservoirs in this area. S. turricula has been subdominant in molluscan communities. Sixteen molluscan species, including 11 gastropod and 5 bivalve species, were recorded at the sampling sites. Based on a redundancy analysis (RDA), the organic matter content in the bottom sediments and pH were the parameters most associated (statistically significant) with the distribution of molluscan species including S. turricula.     

Changes in incidence and prognosis of ischaemic heart disease in Finland: a record linkage study of data on death certificates and hospital records for 1972 and 1981.

The components of the decline in mortality from ischaemic heart disease in Finland were studied by analysing the changes in incidence and prognosis between 1972 and 1981. Using personal identification numbers, hospital discharge records and death certificates were linked for all men and women aged 40-64. During this period mortality decreased 15.9% in men and 23.5% in women, incidence 14.2% in men and 19.3% in women, being greatest among 40-49 year olds living in urban areas, and case fatality 7.3% in men and 10.3% in women, owing primarily to a decrease in patients dying of ischaemic heart disease without being admitted to hospital; survival was also better among patients admitted to hospital. Factors explaining these changes remain unknown because data on risk factors and factors influencing prognosis are limited and largely ecological.     

Magic angle spinning (MAS) NMR: a new tool to study the spatial and electronic structure of photosynthetic complexes

Photosynthesis Research - In the last two decades, Magic Angle Spinning (MAS) NMR has created its own niche in studies involving photosynthetic membrane protein complexes, owing to its ability to...     

The linkage with apolipoprotein (a) in lipoprotein (a) modifies the immunochemical and functional properties of apolipoprotein B

Lipoprotein (a) [Lp(a)] was isolated from several donors and its apolipoprotein (a) [apo(a)] dissociated by a reductive treatment, generating the apo(a)-free form of Lp(a) [Lp(a--)] that contains apolipoprotein B (apo B) as its sole protein. Using anti-apo B monoclonal antibodies, the properties of apo B in Lp(a), Lp(a--), and autologous low-density lipoprotein (LDL) were compared. Marked differences in apo B immunoreactivity were found between these lipoproteins, due to the presence of apo(a) in Lp(a). Apo(a) enhanced the expression of two epitopes in the amino-terminal part of apo B while it diminished the immunoreactivity of three other epitopes in the LDL receptor binding domain. Accordingly, the binding of the lipoproteins to the LDL receptor was also decreased in the presence of apo(a). In a different experimental system, the incubation of antibodies that react with 27 distinct epitopes distributed along the whole length of apo B sequence with plastic-bound Lp(a) and Lp(a--) failed to reveal any epitope of apo B that is sterically hindered by the presence of apo(a). Our results demonstrate that the presence of apo(a) modified the organization and function of apo B in Lp(a) particles. The data presented indicate that most likely the modification is not due to a steric hindrance but that some more profound conformational changes are involved. We suggest that the formation of the disulfide bridge between apo B and apo(a) in Lp(a) alters the system of disulfide bonds present in apo B and thereby modifies apo B structure.     

End-to-end linkage (EEL) clustering algorithm: a study on the distribution of Meissner corpuscles in the skin

A novel hierarchical clustering algorithm was applied to the distribution of Meissner corpuscles in the skin of mammals. This method, called end-to-end linkage (EEL), is useful for grouping data that consists of chain-like contingencies in the multivariable space. Unlike the traditional techniques which uncover hyperspherical clusters (e.g. single linkage), EEL considers the shortest distance between the predefined end pairs of the two clusters as an inter-group distance. This scheme allows characterizing the internal structure of data better than other hierarchical techniques. The anatomical data used in the case study is important for studying the sense of touch. The results show a substantial improvement over the traditional single-linkage method. On average, the number of correctly classified corpuscles is increased to twice the number identified by the single-linkage method. EEL can also be used for analyzing other sensory modalities where geometric relationships need to be explored. In addition, the report contains corpuscle density and epidermal-ridge width data obtained from several species.     

The electronic structure of and conformational energy barrier to rotation a round the C-N glycosidic linkage in adenosine-3',5'-cyclicmonophosphate (cyclic AMP) and its phosphonate analog

Extended Hückel molecular orbital calculations are reported on cyclic AMP and its phosphonate analog. A parallel Lennard-Jones potential and molecular orbital study on the barrier to rotation of the adenine base around the sugar phosphate moiety indicates a rather low barrier for both molecules studied (6.6 kcal/mole and less than 6 kcal/mole for the cyclic phosphate and cyclic phosphonate, respectively) with most favorable syn and anti forms possessing similar energies. According to the calculations this low barrier may be the most distinguishable property when compared to the molecule's precursor ATP and enzymically derived product 5′-AMP.     

X-linked alpha-thalassemia/mental retardation (ATR-X) syndrome: localization to Xq12-q21.31 by X inactivation and linkage analysis.

We have examined seven pedigrees that include individuals with a recently described X-linked form of severe mental retardation associated with alpha-thalassemia (ATR-X syndrome). Using hematologic and molecular approaches, we have shown that intellectually normal female carriers of this syndrome may be identified by the presence of rare cells containing HbH inclusions in their peripheral blood and by an extremely skewed pattern of X inactivation seen in cells from a variety of tissues. Linkage analysis has localized the ATR-X locus to an interval of approximately 11 cM between the loci DXS106 and DXYS1X (Xq12-q21.31), with a peak LOD score of 5.4 (recombination fraction of 0) at DXS72. These findings provide the basis for genetic counseling, assessment of carrier risk, and prenatal diagnosis of the ATR-X syndrome. Furthermore, they represent an important step in developing strategies to understand how the mutant ATR-X allele causes mental handicap, dysmorphism, and down-regulation of the alpha-globin genes.     

The science of sex and gender in human health: online courses to create a foundation for sex and gender accountability in biomedical research and treatment

Background

Sex and gender differences play a significant role in the course and outcome of conditions that affect specific organ systems in the human body. Research on differences in the effects of medical intervention has helped scientists develop a number of sex- and gender-specific guidelines on the treatment and management of these conditions. An online series of courses, “The Science of Sex and Gender in Human Health,” developed by the National Institutes of Health Office of Research on Women’s Health and the U.S. Food and Drug Administration Office of Women’s Health, examines sex and gender differences and their implications. Thus far, three online courses have been generated. The first course offers an overview of the scientific and biological basis for sex- and gender-related differences. The second course is focused on disease-specific sex and gender differences in health and behavior and their implications. Finally, the third course covers the influence of sex and gender on disease manifestation, treatment, and outcome.

Methods

Data were obtained using website analytics and post-course surveys.

Results

To date, over 1000 individuals have completed at least one course. Additionally, 600 users have received continuing education credit for completing a course in the series. Finally, the majority of respondents to the online course survey have indicated that the courses considerably enhanced their professional effectiveness.

Conclusions

“The Science of Sex and Gender in Human Health” online courses are freely available sources of information that provide healthcare providers and researchers with the resources to successfully account for sex and gender in their medical practice and research programs.