Sex ratio in offspring of pilots: a contribution to stress research

An old rumor - lately substantiated by statistical examinations from England - to the effect that pilots of high-performance military aircraft are "girl-fathers", could be reduced to absurdity through a comprehensive questionnaire investigation in the German Federal Armed Forces. Spermiogenesis does not seem to be disturbed by professional-specific influences (Radar radiation, G-forces etc.), as implied by the questionnaire findings. In times of high flying and personal stress (first 1000 flying hours) military jet pilots are even "boy-fathers". As soon as flying becomes a routine matter (after the 1000th flying hour) and thus less stressful, jet and helicopter pilots even become "girl-fathers". The pilots of military transport aircraft show no deviation from the control group of the male population of the Federal Republic of Germany with respect to the sex ratio of children procreated by them. The intention of this somewhat curious study was established by considerations that pilots would be entitled to protection and/or compensation for damages incurred in cases where their procreative capacity had been detrimentally affected by activities in the line of duty.     

Sex ratio and parental age gap

We compare the physicochemical and functional characteristics of nucleoplasmin obtained from Xenopus laevis oocytes and by bacterial overexpression of a plasmid containing the nucleoplasmin gene. The comparison shows that, while the secondary structure of the protein is not affected by the method used to obtain this protein, the bacterial expressed form exhibits a marked tendency to form large aggregates and an impaired ability to displace protamines from sperm nuclei. These results add a word of caution to the indiscriminate use, in functional or structural (crystallographic) studies, of bacterially overproduced proteins that have been end-terminally tagged with polyhistidine.     

The sex ratio of offspring of people exposed to boron

We report herein the case of a 49-year-old woman with Pendred's syndrome who developed follicular carcinoma of the thyroid and invasive ductal carcinoma of the breast. To the best of our knowledge, this is the first case of different primary neoplasms developing in a patient with Pendred's syndrome.     

Experimental demonstration that offspring sex ratio varies with maternal condition

Sex ratio theory predicts that, if prevailing ecological or social circumstances differentially influence the fitness benefits of offspring of each sex, parents should adjust their production accordingly to maximize fitness. For species in which sex is chromosomally determined, such as birds and mammals, a differential effect of maternal condition on the fitness of male and female young is one important route whereby selection is expected to favor a bias in the offspring sex ratio at birth or egg laying. However, despite its central place in sex allocation theory, this hypothesis has rarely been tested in wild populations. We manipulated maternal condition upward and downward in a sexually dimorphic wild bird and examined the effect on offspring survival and on offspring sex ratio. The survival to fledging of male, but not female, young was substantially reduced if they came from less well provisioned eggs produced by females in relatively poor condition. As female condition, and thereby her capacity to produce high quality eggs, declined, she progressively skewed the sex ratio of her eggs toward females; i.e., she produced more of the sex with the higher survival prospects. The decline in the survival of male offspring, and the sex ratio bias, was removed when maternal condition was enhanced. These results provide experimental evidence of an adaptive, facultative adjustment of sex ratio in response to changes in maternal condition in wild birds.     

Lipoproteins, apolipoproteins, and low-density lipoprotein size among diabetics in the Framingham offspring study

Diabetes mellitus has been shown to be associated with lipid abnormalities. Prior studies have indicated that women with diabetes have a risk of coronary heart disease similar to that of men. We compared lipid parameters in diabetic and nondiabetic participants in cycle 3 of the Framingham Offspring Study. Values for plasma total cholesterol (TC), triglyceride, lipoprotein, cholesterol, apolipoprotein (apo) A1, B, apo and lipoprotein(a) [Lp(a)] and low-density lipoprotein (LDL) particle size were analyzed in 174 diabetic and 3,757 nondiabetic subjects. Data from a total of 2,025 men and 2,042 women participating in the third examination (1983 to 1987) of the Framingham Offspring Study were subjected to statistical analysis. Male and female diabetics showed lower high-density lipoprotein (HDL) cholesterol, higher triglycerides, higher very-low-density lipoprotein (VLDL) cholesterol, lower apo A1, and higher LDL particle scores, indicating smaller size, than nondiabetics. Female diabetics also showed significantly higher TC and apo B values than nondiabetics. The results remained statistically significant after controlling for obesity and menopausal status. The presence of small dense LDL particles (pattern B) was highly associated with diabetes and hypertriglyceridemia in both sexes, and the relative odds for pattern B remained significant in women but not in men after adjustment for age and hypertriglyceridemia. No differences in apo E isoform distribution were found for diabetics and nondiabetics. Diabetes was not associated with elevated LDL cholesterol levels. In conclusion, diabetics have lower HDL cholesterol and higher triglyceride levels and are more likely to have small dense LDL particles. Diabetes is not a secondary cause of elevated LDL cholesterol. Lipid screening of diabetics should include full quantification of lipids for proper assessment of potential atherosclerotic risk.     

Sex ratio in the progeny of mothers with toxemia of pregnancy

Maternal-fetal incompatibility may be an essential component in the etiology of toxemia of pregnancy. A prior study found an abnormally high sex (male:female) ratio, suggestuve of Y-dependent histoincompatibility. We studied the records of 373 patients alleged to have some indication of toxemia among 3,246 births and applied standard criteria for classification. There were no significant differences for any group compared with the sexondary sex ratio expected of the population(94.6% Black).     

Sex ratio at birth deviations in modern Venezuela: the Trivers-Willard effect

This study evaluates the impact of the Trivers-Willard (T-W) effect on human populations, using demographic data collected from vital registration data in Venezuela. The evaluation of the sex ratio at birth (SRB) and of fetal and infant deaths supports the existence of T-W effect in the Venezuelan population in extreme conditions. This T-W effect was observable in the SRB but not at later ages and is related to the marital status of the mother. The results indicate that the investment in females associated with environmental adversity is greater than the investment in males associated with good environmental conditions.     

Sex ratio adjustment in relation to paternal attractiveness in a wild bird population

When the relative fitness of sons and daughters differs, sex-allocation theory predicts that it would be adaptive for individuals to adjust their investment in different sexes of offspring. Sex ratio adjustment by females in response to the sexual attractiveness of their mate would be an example of this. In vertebrates the existence of this form of sex ratio adjustment is controversial and may be confounded with sex-biased mortality, particularly in sexually size-dimorphic species. Here we use PCR amplification of a conserved W-chromosome-linked gene to show that the sex ratio within broods of a natural population of sexually size-monomorphic collared flycatchers Ficedula albicollis is related to the size of their father's forehead patch, a heritable secondary sexual character implicated in female choice. Experimental manipulations of paternal investment, which influence the size of his character in future breeding attempts, result in corresponding changes in the sex ratio of offspring born to males in those breeding attempts. In contrast, manipulations of maternal investment have no effect on future sex ratios, and there is no relationship between variables predicting the reproductive value of the brood and nestling sex ratio. Analysis of recruitment of offspring reveals similar patterns of sex ratio bias. The results suggest that female collared flycatchers be able to adjust the sex ratio of eggs ovulated in response to the phenotype of their mate. This finding is most consistent with "genetic quality" models of sexual selection.     

Prevention of atherosclerosis in diabetics

The high prevalence of atherosclerotic (macrovascular) complications in diabetes (1.5-6x higher than in non-diabetics) stimulated evaluation of new pathogenetic findings which could have an impact on prevention. In type 1 diabetics the development of nephropathy is a factor hastening the development of macroangiopathy. In type 2 diabetics on whom attention is concentrated at the moment interaction of various metabolic deviations is involved which include changes of lipoproteins (drop of HDL, changes in the size and composition of LDL), insulin resistance and glycosylation of proteins. There is an enhanced tendency to lipoprotein oxidation (LDL) which promote the development of cholesterol rich plaques in the arterial walls. Their rupture may cause occlusion and ensuing risks for life. Possibilities of prevention are not adequately made use of. This is due to a tendency to underrate the serious character of type 2 diabetes and also the high percentage of diabetics where the disease was diagnosed late. The metabolic syndrome which develops as a result of insulin resistance precedes for years manifestations of diabetes. Its detection makes it possible to screen subjects at risk, some of whom develop diabetes. At the same time it is also a pathogenetic factor of macrovascular complications. It leads to the cumulation of a number of risk conditions. More effective prevention can be implemented by intervention of all associated risk factors (smoking, hypertension), in the application of lifestyle provisions of energy reduction by promoting physical activity and by a rational diet (diabetes, obesity, hyperlipidaemia). The justification of pharmacotherapy for the high risk groups of diabetics with hyperlipidaemia is supported by results of recently published investigations where statins were used. For the sub-population of subjects at risk the perspective should be screening of risk factors, early diagnosis of diabetes, education, continuous primary care, comprehensive prevention using lifestyle provisions as well as advances in modern pharmacotherapy.     

The quality of life of diabetics

The purposes of this study were to identify the meaning of the quality of life for the people who suffer from Diabetes Mellitus, to recognize the aspects which affect most their lives due to this disease and the degree of the satisfaction in their lives as well. Participated in this research forty-six (46) diabetic patients, adults of both sexes, who were in a polyclinic for treatment. The results showed that the meaning of the quality of life had priority related to the physical well-being (54.5%), to the social and economical stability (26.0%), and to the spiritual and emotional well-being (16.9%). The most affected aspects due to this disease were: studying and home activities (38.5%) physical ability (25.6%) and family relationship (10.3%). Concerning about the degree of satisfaction with their lives, the majority of them (66.6%) considered themselves satisfied or very satisfied. It is worth while to point out the importance of considering the multimensionality of the concept of quality of life while attending the diabetic person.