Variation of sex ratio and ABO blood group composition by month of birth of blood donors in Tokyo

Sex ratio of 17,273 blood donors born during the period between 1925 and 1935 was examined according to their month of birth and ABO blood groups in comparison with 5,810 healthy non-blood donors born in the 1900s to 1930s. The sex ratio of the blood donors and the non-blood donors varied similarly according to their month of birth with a prominent peak in summer births and a trough in winter births. This birth season with a high sex ratio was different from that of the general births during the period between 1921 and 1935, in which a maximum sex ratio was found in November. A possible explanation for the difference is the different rate of male and female infant deaths according to birth month. Variation of the sex ratio according to season of birth was not similar among the four ABO blood groups. Sex ratio of the donors with blood group B showed no elevation among the summer births. Non-blood donors with blood group B, on the contrary, showed a higher sex ratio than the others in the summer births. This difference can not be explained by infant or juvenile deaths. A possibility is that a tendency to become a blood donor is modified by the season of one's birth differently according to gender and ABO blood groups.     

Familial resemblance in maximal heart rate, blood lactate and aerobic power

There are considerable interindividual differences in maximal oxygen uptake per kilogram of body weight (VO2 max/kg), maximal heart rate (max HR) and maximal blood lactate (max blood La) measured during a progressive exercise test. The aim of the study was to quantify the familial relationships for these variables. Parents and children of 38 families of French-Canadian descent were submitted to a modified Balke treadmill test. VO2 max/kg and max HR were the highest values reached during the test for 1 min. Max blood La was obtained from a blood sample taken 2 min after the test. The effects of age and sex were significant for max blood La and VO2 max/kg in each generation. Scores were thus adjusted through multiple regression procedures (age + sex + age X sex + age2), yielding residuals which were submitted to further analysis. Intraclass correlations (ri) were significant in pairs of sibs for max blood La and max HR, i.e. 0.28 (p less than 0.01) and 0.43 (p less than 0.05), respectively. For VO2 max/kg, pairs of spouses and sibs were about similarly correlated (ri = 0.20 and 0.15; p less than 0.05). Data suggested that children were more related to their mother than to their father for VO2 max/kg, VO2 max/kg of fat-free weight, and particularly for max HR. It was concluded that familial resemblance and heritability estimates for maximal aerobic power, max HR and max blood La were quite low and generally nonsignificant. Correlations between biological sibs were, however, consistently significant for max HR and max blood La. The suggestion of a maternal effect in maximal aerobic power should be further investigated.     

Are oral clefts a consequence of maternal hormone imbalance? evidence from the sex ratios of sibs of probands

BACKGROUND: The causes of oral clefts (cleft lip with or without cleft palate, CL/P, and cleft palate alone, CP) have not been established. However, maternal intrauterine hormone profiles have been suspected of being involved. There is now substantial evidence that maternal hormone concentrations around the time of conception partially control the sexes of offspring. It is possible that the hormone profiles that control sex of offspring share features of the profiles suspected of causing clefts. This can be tested by examining the sex ratios (proportions male) of the unaffected sibs of probands. If these sex ratios are skewed in the same direction as that of probands, that suggests, ex hypothesi, maternal hormonal involvement in the causation of clefts. METHODS: Accordingly, a search was made for data on the sex ratios of the unaffected sibs of probands with clefts. For reasons given in the text, this search was informal rather than based on electronic data retrieval systems. Nine papers were located giving sex ratios of sibs of probands with CL/P and CP. RESULTS: Published data suggest that the sibs of probands with CL/P have a significantly higher sex ratio than the sibs of probands with CP. Thus the sib sex ratios are skewed in the same direction as those of the probands themselves. In other words, parents (mothers) of CL/P patients apparently have a tendency to produce boys, and parents of CP patients to produce girls. CONCLUSION: Accordingly, it is suggested that maternal hormone profiles may partially explain the unusual sex ratios (of probands and their sibs), as well as the malformations.     

HIV-1-specific mucosal CD8+ lymphocyte responses in the cervix of HIV-1-resistant prostitutes in Nairobi

Understanding how individuals with a high degree of HIV exposure avoid persistent infection is paramount to HIV vaccine design. Evidence suggests that mucosal immunity, particularly virus-specific CTL, could be critically important in protection against sexually acquired HIV infection. Therefore, we have looked for the presence of HIV-specific CD8+ T cells in cervical mononuclear cells from a subgroup of highly HIV-exposed but persistently seronegative female sex workers in Nairobi. An enzyme-linked immunospot assay was used to measure IFN-gamma release in response to known class I HLA-restricted CTL epitope peptides using effector cells from the blood and cervix of HIV-1-resistant and -infected sex workers and from lower-risk uninfected controls. Eleven of 16 resistant sex workers had HIV-specific CD8+ T cells in the cervix, and a similar number had detectable responses in blood. Where both blood and cervical responses were detected in the same individual, the specificity of the responses was similar. Neither cervical nor blood responses were detected in lower-risk control donors. HIV-specific CD8+ T cell frequencies in the cervix of HIV-resistant sex workers were slightly higher than in blood, while in HIV-infected donor cervical response frequencies were markedly lower than blood, so that there was relative enrichment of cervical responses in HIV-resistant compared with HIV-infected donors. HIV-specific CD8+ T cell responses in the absence of detectable HIV infection in the genital mucosa of HIV-1-resistant sex workers may be playing an important part in protective immunity against heterosexual HIV-1 transmission.     

A genetic study of Hirschsprung disease

Hirschsprung disease, or congenital aganglionic megacolon, is commonly assumed to be a sex-modified multifactorial trait. To test this hypothesis, complex segregation analysis was performed on data on 487 probands and their families. Demographic information on probands and the recurrence risk to relatives of probands are presented. An increased sex ratio (3.9 male:female) and an elevated risk to sibs (4%), as compared with the population incidence (0.02%), are observed, with the sex ratio decreasing and the recurrence risk to sibs increasing as the aganglionosis becomes more extensive. Down syndrome was found at an increased frequency among affected individuals but not among their unaffected sibs, and the increase was not associated with maternal age. Complex segregation analysis was performed on these family data. The families were classified into separate categories by extent of aganglionosis. For cases with aganglionosis beyond the sigmoid colon, the mode of inheritance is compatible with a dominant gene with incomplete penetrance, while for cases with aganglionosis extending no farther than the sigmoid colon, the inheritance pattern is equally likely to be either multifactorial or due to a recessive gene with very low penetrance. A model of gene action with random effects during morphogenesis is compatible with our observations.     

The association of sex ratio anomalies with pyloric stenosis

Published family data were examined for evidence of aberrant sex ratios in relatives of pyloric stenosis index cases. An excess of males over females was found among unaffected members of sibships in which there occurred more than one case of pyloric stenosis. The male excess among affected members of these sibships did not differ from that among index cases without affected sibs. An unusual frequency of spontaneous abortions in these subships, which might account for the observed excess of males, was not observed. No evidence was found of sex ratio anomalies in other classes of relative of pyloric stenosis index cases, whether or not the index cases had affected sibs.     

Coexpression of CCR5 and IL-2 in human genital but not blood T cells: implications for the ontogeny of the CCR5+ Th1 phenotype.

Memory T cells that home to inflamed tissues typically express the beta-chemokine receptor CCR5 and exhibit a Th1 cytokine profile. The migration of these cells into the genital tract following antigenic exposure has particular relevance to acquisition of HIV-1 infection, because CCR5 functions as the coreceptor for most sexually transmitted HIV-1 strains. We recently established methodology to purify and culture mononuclear cells from the female reproductive tract, and here we analyzed the phenotype, CCR5 expression, and cytokine production of cervicovaginal T cells in up to 16 donors. The proportion of mucosal T cells expressing CCR5 was markedly expanded as compared with peripheral blood (mean 88% vs 24% in 13 donors), but the receptor density on individual CCR5+ T cells was only slightly increased (mean 5837 vs 4191 MEPE (molecules of equivalent PE) units in 6 of 7 donors). Intracellular costaining for IL-2, IFN-gamma, IL-4, and IL-5 revealed a Th1-type pattern in cervical T cells, with significantly higher percentages of IL-2- and IFN-gamma-producing T cells in the mucosa than in blood (mean 67% vs 29%). Coexpression of surface CCR5 with intracellular IL-2 and IFN-gamma was observed only among T cells in the mucosa, but not among those in circulation. Thus, we postulate that T cell homing to the genital mucosa leads to differentiation into the combined CCR5+ Th1 phenotype. Moreover, the predominance of CCR5+ Th1-type T cells in normal cervical mucosa provides targets accessible for the efficient transmission of macrophage-tropic HIV-1 variants in women following sexual exposure.     

Reliability of the cut-off value in the routine serodiagnosis of pertussis performed by the commercial ELISA assays

In clinical practise, serodiagnosis of pertussis is mostly based on single-sample serology using a single cut-off. The reliability of the cut-off value has the crucial influence for the sensitivity and specificity of the used tests. In this context we compared the value of cut-off used in two commercial ELISA kits (NovaLisa Bordetella pertussis-NovaTec and ELISA Bordetella pertussis ELISA-Virotech) with cut-off settled by calculation the IgA and IgG results from the 60 healthy Polish children and 100 blood donors (arithmetic mean plus 2 or 3 standard deviations). Our study indicates that IgA cutoff used in NovaTec ELISA, in contrary to Virotech ELISA, correspond better to the level x+3SD calculated in children sera and x+2SD calculated in adult blood donors sera. The value of IgG cut-off used in Virotech ELISA was lower about 20% and 30% from the cut-off settled by us respectively on the level ofx+2SD and x+3SD in all tested sera. The most inadequate value had the IgG cut-offused in NovaTec ELISA, which was over three times lower than mean cut-off value settled by calculation results from the sera obtained from healthy children and blood donors. This low cut-off value established by the NovaTec was the reason that 23.3% of healthy children and 55.0% of blood donors have the IgG antibodies on the diagnostic significant level. Our data suggest that commercial ELISAs need further improvement and standardization.     

Brothers and sisters

Data from the Kipsigis of Kenya are used to test two models for how parents invest in offspring, the Trivers-Willard and local resource competition/enhancement hypotheses. Investment is measured as age-specific survival, educational success, marital arrangements, and some components of property inheritance, permitting an evaluation of how biases persist or alter over the period of dependence. Changes through time in such biases are also examined. Despite stronger effects of wealth on the reproductive success of men than women, the survival of sons and daughters is not related to parental wealth. However, a Trivers-Willard effect characterizes educational investment: poor families show a greater concern for daughters’ (vis-à-vis sons’) schooling than do rich families, a trend that has increased over time. In regard to models of local resource competition and enhancement, men’s reproductive success decreases with number of brothers and increases with number of sisters; this pattern of competition with same-sex sibs and cooperation with opposite-sex sibs is not found among women. As predicted from these observations, parents show reduced investment in sons with a large number of brothers, and increased investment in sons with a large number of sisters. By contrast, investment in daughters is entirely unaffected by number of sisters and is influenced only in subtle ways by number of brothers. Levels of investment in relation to sibship size (irrespective of siblings’ sex) are highest for younger children of large sib sets. Discussion of the results in relation to those from other studies leads to three conclusions. First, predictive models for how investment biases vary across societies must consider a broad range of socioecological factors constraining parental options and payoffs. Second, the timing of investment biases within societies will be affected by the value of children and the costs of parental investment. Third, measures of investment appropriate for between-sex and between-class comparisons need careful attention. Each of these issues is brought to bear on the question of why, in contrast to so many other parts of the world, sex preferences are so muted in Africa.     

Levels of Circulating DNA in Blood Serum and DNA Damage in Leukocytes of Healthy Donors of Different Genders and Ages

We studied the levels of extracellular nuclear and mitochondrial DNA of blood serum and DNA damage in leukocytes of healthy donors of different sex and age groups. The baseline levels of DNA damage in leukocytes and serum DNA levels were shown to vary greatly among different donors. The baseline level of DNA damage in leukocytes was not associated with the presence of chronic deceases or an occupational health risk for elderly donors. It was found that extracellular DNA concentrations were generally higher in men than in women. There is a tendency towards an increase in the relative mitochondrial DNA copy number determined by ΔCt in women but not in men: the relative mtDNA copy number in elderly individuals varies significantly in both sexes, possibly due to age-related physiological changes. It is necessary to consider the gender and age of patients when using an indicator such as the level of extracellular DNA of blood serum for diagnosis and monitoring.

     

Chromosomal radiosensitivity in common variable immune deficiency

From more than 500 tumours reported in human primary immune deficiencies a majority has been observed in two disorders: ataxia telangiectasia (A-T) and common variable immune deficiency (CVID). Since both diseases have an increased risk of lymphomas/leukaemias and gastrointestinal tumours, suggesting a common risk factor, and the cells derived from A-T patients exhibit an increased chromosomal radiosensitivity we analysed chromosome damage in the G₂ lymphocytes of 24 CVID pateints and 21 controls after X-irradiation in vitro.

There was a significant difference in mean aberration yields between patients and controls. Three CVID patients had yields higher than the mean + 3SD of the controls. Six patients but only one control had yields higher than the mean + 2SD of controls. The patient with the highest chromosomal radiosensitivity subsequently developed a lymphoma. Repeat assays on the same blood sample, with a 24-h delay in setting up the second culture, showed as much variability for control donors as the variation between control donors although for CVID patients inter-individual variation was greater than the difference between results of repeat samples. There was a weak positive correlation between radiosensitivity and age of donor. Chromosomal radiosensitivity of five patients with X-linked hypogammaglobulinaemia was not different from healthy donors.

The mean mitotic index (MI) for unirradiated samples from CVID patients was significantly lower than for controls and there was an inverse relationship between MI and aberration yields in the patients, but not in controls. We suggest that the defect in CVID patients that reduces response to mitogenic stimuli may have mechanism(s) in common with those involved in cellular repair processes.     

Risk of HIV infection from blood transfusion in Montreal

OBJECTIVES: To determine the incidence (including associated donor characteristics and time trends) of HIV infection among repeat blood donors and to estimate the risk of HIV transmission from blood transfusion in Montreal and in Canada as a whole. DESIGN: Retrospective cohort analysis. SETTING: Montreal Centre Blood Transfusion Service. PARTICIPANTS: People who donated blood at least twice after Nov. 1, 1985, and at least once from Apr. 1, 1989, to Mar. 31, 1993. INTERVENTION: Blood was screened for HIV by enzyme-linked immunosorbent assay and results were confirmed by Western blot analysis. OUTCOME MEASURES: Incidence density (the incidence rate per person-time) of HIV infection among repeat blood donors by sex, age group and region of residence, and incidence density and risk among first-time donors and for Canada as whole. RESULTS: There were 200,196 eligible donors and 432,631 person-years (PY) of observation. From 1989 to 1993, there were 18 HIV seroconversions among repeat donors. The crude incidence density was 3.3 per 100,000 PY (95% confidence interval [CI] 1.8 to 5.4 per 100,000 PY); it was 4.9 per 100,000 PY among men and 0.61 per 100,000 PY among women. Age-specific incidence per 100,000 PY was 2.5 among those 12-29 years of age, 5.1 among those 30-49, 2.9 among those 40-49, and 1.4 among those 50 and older. Based on an estimated mean "window period" (from when a donor''s blood is capable of transmitting HIV until detectable antibody appears) of 25 days, the current risk of HIV infection from repeat donors in the window period is estimated at 1 in 440,000. Inclusion of blood units from first-time donors produces an overall risk of 1 in 390,000 (95% CI 1 in 250,000 to 655,000). The estimated risk per blood unit in Canada as a whole is 1 in 913000 (95% CI 1 in 507,000 to 2,050,000). CONCLUSIONS: This "sentinel" population of repeat blood donors is subject to important trends in HIV spread. Therefore, estimating the incidence density of HIV infection in repeat donors provides insight into the epidemiologic characteristics of HIV infection at minimal expense. As a result of measures to improve blood safety, including HIV testing, the incidence of HIV infection among blood donors in Canada is low and the risk of HIV transmission from transfusion is extremely small, although not zero.     

The Effects of Inflorescence Size and Flower Position on Biomass and Temporal Sex Allocation in <Emphasis Type="Italic">Lobelia sessiliflora</Emphasis>

To test the prediction of sex allocation theory that plants or flowers high in resource status emphasize the female function, we explored the variation in both biomass (the number of pollen grains and ovules) and temporal (male and female durations) sex allocation among and within plants of protandrous Lobelia sessilifolia in relation to plant size and flower position within plants. Among plants, the mean number of pollen grains and ovules per flower of a plant increased with plant size, whereas the mean P/O ratio (number of pollen grains/number of ovules ratio) decreased with plant size. The mean male duration, the mean female duration, and the mean ratio of male duration/flower longevity per flower of a plant were not correlated with plant size. Thus, large plants emphasized female function in terms of biomass sex allocation, which is consistent with the prediction of size-dependent sex allocation theory. The results for temporal sex allocation, however were inconsistent with the theory. Within plants, the mean number of pollen grains and ovules per flower at each position decreased from lower to upper flowers (early to late blooming flowers) and that of the P/O ratio increased from lower to upper flowers. The mean male duration and the mean female duration per flower decreased from lower to upper flowers, whereas the mean ratio of male duration/flower longevity increased from lower to upper flowers. The population sex ratio changed from male-biased to female-biased. Thus, later blooming flowers emphasized the male function in terms of both biomass and temporal sex allocation, consistent with the sex allocation theory, regarding the change in the population sex ratio.     

The sex ratio in spina bifida

It is shown that the well known excess of females in spina bifida children is statistically significant when they are compared with (a) the general population and (b) their sibs.Although there is a small excess of males amongst the sibs this is not statistically significant when compared with the general population and when all the children in these families are considered they appear to have a sex ratio very similar to that general population. The sibs of the parents of spina bifida children show a statistically significant excess of females.These findings are discussed with particular reference to the genetics of spina bifida.     

Update on a titration method for measuring the interferon-producing capacity in humans

To make it possible to measure the interferon-alpha (IFN-alpha) producing capacity in a great number of healthy donors and patients, we developed the simple method (the whole blood method). For the measurement of the IFN-producing capacity, the heparinized blood was incubated with Sendai virus at 37 degrees C for 20 hours. The IFN activity of the culture supernatants was determined by the cytopathic effect inhibition assay. We measured the IFN-producing capacity in 531 healthy donors and 130 cancer patients. The results showed that the IFN-producing capacity in cancer patients was significantly lower than that in healthy donors. Although there were individual variations in the IFN-producing capacity, no age and sex differences were observed. These results indicate that this method is useful for the measurement of IFN-producing capacity in human.     

Sex-linked altruism: A stepping-stone in the evolution of social behavior?

A verbal model is presented for a mechanism that enhances the probability of the evolution of altruism in diploids if the gene for altruism arises on the X chromosome. If the altruism takes place between sibs of the homogametic sex, the condition for spread of a sex-linked gene for altruism is less stringent than for an autosomal gene. Then, with altruistic behavior present, selection for increased efficiency (benefit/cost ratio) may raise the efficiency above the autosomal threshold before autosomal modifiers are widespread enough to eliminate the behavior. The results of computer simulations confirms that, if the initial benefit/cost ratio is lower than 2, sex-linkage can make the evolution of altruism more likely.     

Endogenous lithium and boron red cell-plasma ratios: normal subjects versus bipolar patients not on lithium therapy

This study was undertaken to compare endogenous lithium concentrations in human blood and its components from normal donors versus bipolar patients. The patients were not on lithium therapy at the time that the blood samples were donated and had not received any lithium therapy for at least 2 yr. Blood components were separated by centrifugation. The analytical method for lithium as developed in this laboratory consists of thermal-neutron activation of freeze-dried samples. 3H is produced via the reaction 6Li + n = 3H + 4He, and high-sensitivity rare gas mass spectrometry is used to measure 3He formed from beta-decay of 3H. Boron measurements are made concurrently using 4He from the reaction 10B + n = 4He + 7Li. Seven normal donors and seven patients with a diagnosis of bipolar disorder participated in this study. Measurements of lithium and boron were made in whole blood, plasma, and red cells. Red cell-plasma ratios R(Li) and R(B) were calculated after corrections were made for trapped plasma in the red cells. The results show that bipolar patients may have higher concentrations of lithium in blood, plasma, and red cells (p = 0.08, 0.02, and 0.02, respectively) and may have higher R(Li) values than normal donors (p = 0.01). No evidence was found for bipolar-normal differences in these four parameters for boron. Although our sample size is admittedly very small, the results clearly show that the endogenous red cell ratio R(Li) and plasma or red cell lithium concentrations may become useful diagnostic indicators for bipolar illness if the analytical methods are further developed.     

Resources and pollinators contribute to population sex-ratio bias and pollen limitation in Fragaria virginiana (Rosaceae)

Populations of gynodioecious species vary in the ratio of female versus hermaphroditic individuals they contain, and many exhibit higher frequencies of females under poor resource conditions. One important factor limiting female frequencies within populations is predicted to be pollen limitation of seed production, caused by either low abundance of pollen donors or insufficient pollen transfer. However, empirical studies measuring variation in pollen limitation with population sex ratios or resource gradients in gynodioecious plants are inconsistent. Part of this inconsistency may be that pollen limitation and its causes are context-dependent. Another possibility is that sex-specific daily flower production and/or sex-biased visitation are more relevant to the likelihood of pollen limitation than sex ratio based on counting individual plants. In this study, we examined context-dependent pollen limitation in gynodioecious/subdioecious Fragaria virginiana . We specifically examined the potential for resource availability to influence sex-specific daily flower production, sex-biased pollinator visitation, and their relationships with pollen limitation in experimental populations that contained either high or low frequencies of female plants. High resource availability reduced apparent female frequency by increasing daily flower production by hermaphrodites relative to females. This is important because pollinators increasingly discriminated against female flowers as floral sex ratios became more female-biased. Contrary to expectation, females in high-female populations were not consistently more pollen limited than those in low-female populations. The level of pollen limitation of females was better explained by sex–biased pollinator foraging and visitation frequency than by the plant sex ratio or floral sex ratio. Thus, negative frequency dependence of female pollen limitation was evident only considering sex ratio bias mediated by pollinator visitation.     

Similar estimates of population genetic composition and sex ratio derived from carcasses and faeces of Eurasian otter Lutra lutra

Collecting faeces is viewed as a potentially efficient way to sample elusive animals. Nonetheless, any biases in estimates of population composition associated with such sampling remain uncharacterized. The goal of this study was to compare estimates of genetic composition and sex ratio derived from Eurasian otter Lutra lutra spraints (faeces) with estimates derived from carcasses. Twenty per cent of 426 wild-collected spraints from SW England yielded composite genotypes for 7-9 microsatellites and the SRY gene. The expected number of incorrect spraint genotypes was negligible, given the proportions of allele dropout and false allele detection estimated using paired blood and spraint samples of three captive otters. Fifty-two different spraint genotypes were detected and compared with genotypes of 70 otter carcasses from the same area. Carcass and spraint genotypes did not differ significantly in mean number of alleles, mean unbiased heterozygosity or sex ratio, although statistical power to detect all but large differences in sex ratio was low. The genetic compositions of carcass and spraint genotypes were very similar according to confidence intervals of theta and two methods for assigning composite genotypes to groups. A distinct group of approximately 11 carcass and spraint genotypes was detected using the latter methods. The results suggest that spraints can yield unbiased estimates of population genetic composition and sex ratio.     

Number and sex of offspring of ΔF508 carriers outside cystic fibrosis families

Number and sex of offspring were determined in a group of 7,841 randomly selected blood donors who were screened for the F508 mutation. We did not find any evidence for differences in number or sex ratio of offspring between F508 carriers and non-carriers.