Human breasts: Unsupported hypotheses reviewed

Unlike other apes, human females’ breasts develop before first pregnancy and are permanently enlarged. Evidence suggests breasts act as signals to males but the critical data required to confirm this are lacking. These facts have led to a number of hypotheses about the evolutionary and adaptive significance of the human breast which fall into two groups. Those that address the presence of breasts in humans are (a) that they act as releasers of male sexual behaviour, (b) that they enable females to hide their reproductive condition, and (c) that they allow infants to nurse from their mother’s hip. Those that address variability in breast size are (d) that large breasts indicate lactational potential, (e) ability of mothers to invest prenatally in offspring, (f) mother’s fecundity, and (g) her longevity. Each hypothesis is reviewed and evaluated using logical or empirical arguments. Possible ways in which the adaptive significance of human breasts can be determined in contemporary populations are outlined.     

Value of the history in the office diagnosis of breast cancer.

A review of the histories of 1059 patients with breast problems seen consecutively in office consultation revealed an incidence of breast cancer of 13%. Patients over 50 years of age or whose mother or sister had had breast cancer had a substantially greater likelihood of having breast cancer. The finding of the problem on routine examination, a family history of breast cancer in a relative other than the mother or a sister, or prominent breast pain or nipple discharge made the diagnosis of cancer less likely. Menstrual status, a history of previous benign disease, nulliparity, current hormone therapy and duration of symptoms did not help identify the patient likely to have breast cancer. Much time could be saved for both doctor and patient in taking the history from patients with breast disorders. Only the patient''s age and the history of the mother and sisters with regard to breast cancer will help identify the "high-risk" patient. Other historical findings are either valueless or should be used to reassure these usually anxious women.     

Effect of mother’s physical condition during pregnancy and lactation on postnatal growth and reproductive success of offspring in water vole <Emphasis Type="Italic">Arvicola terrestris</Emphasis>

Postnatal growth, life span, and probability of reproduction in the adult state depended on the mother’s physical condition during pregnancy and lactation in water vole. The white fat weight in the female abdominal cavity was shown to significantly increase in pregnancy and to decrease in late lactation. As an indicators for nutritional state of females, their body weight difference after parturition (or in late lactation) and expected from the regression equation relating individual body weight at the beginning and the end of each reproductive stage were used (physical condition indexes in pregnancy or lactation). The correlation of the physical condition index in pregnancy with the storage fat weight was 0.67. The metabolic resources of the mother’s body proved to favor faster offspring development. The female offspring weight at the age of 3 and 10 weeks as well as adult ones positively correlated with the mother’s nutritional state in pregnancy, while the male offspring weight demonstrated a similar correlation at the age of 3 and 6 weeks. Increased negative energy balance during lactation proved to decrease the offspring weight in both sexes after separation from mother and at the age of 6 weeks. High nutritional state of mother in pregnancy favored both the probability of reproduction and life span of female offspring. The reproduction of male offspring did not depend on the mother’s physical condition. The life span peaked in male offspring of mothers in a nutritional state below average in pregnancy and above average in lactation. Thus, the physical condition of the mother’s body is an important sex-dependent factor of phenotypic variation in the offspring body weight, reproductive competence, and life span.     

Qualitative study of decisions about infant feeding among women in east end of London

ObjectiveTo improve understanding of how first time mothers who belong to a socioeconomic group with particularly low rates of breast feeding decide whether or not to initiate breast feeding.DesignQualitative semistructured interviews early in pregnancy and 6-10 weeks after birth.SettingWomen’s homes in east end of London.Subjects21 white, low income women expecting their first baby were interviewed mostly at home, often with their partner or a relative. Two focus groups were conducted.ResultsWomen who had regularly seen a relative or friend successfully breast feed and described this experience positively were more confident about and committed to breast feeding. They were also more likely to succeed. Exposure to breast feeding, however, could be either a positive or a negative influence on the decision to breast feed, depending on the context. Women who had seen breast feeding only by a stranger often described this as a negative influence, particularly if other people were present. All women knew that breast feeding has health benefits. Ownership of this knowledge, however, varied according to the woman’s experience of seeing breast feeding.ConclusionsThe decision to initiate breast feeding is influenced more by embodied knowledge gained from seeing breast feeding than by theoretical knowledge about its benefits. Breast feeding involves performing a practical skill, often with others present. The knowledge, confidence, and commitment necessary to breast feed may be more effectively gained through antenatal apprenticeship to a breastfeeding mother than from advice given in consultations or from books.

Key messages

• Women who have seen successful breast feeding as part of their daily lives and perceive this as a positive experience are more likely to initiate breast feeding
• Embodied knowledge gained through seeing breast feeding may be more influential than theoretical knowledge about the health benefits for women of lower social class
• Listening to pregnant women talking about breast feeding could help clinicians assess the relative importance of theoretical and embodied knowledge for each woman
• Women hoping to breast feed but with little exposure to breast feeding may benefit from an antenatal apprenticeship with a breastfeeding mother
• Ideally apprenticeship would be with a breastfeeding mother from her social network to minimise the potential barriers of embarrassment and lack of confidence with strangers

     

Study of a single BRCA2 mutation with high carrier frequency in a small population.

Germ-line changes in the cancer-predisposition gene BRCA2 are found in a small proportion of breast cancers. Mutations in the BRCA2 gene have been studied mainly in families with high risk of breast cancer in females, and male breast cancer also has been associated with BRCA2 mutations. The importance of germ-line BRCA2 mutations in individuals without a family history of breast cancer is unknown. The same BRCA2 mutation has been found in 16/21 Icelandic breast cancer families, indicating a founder effect. We determined the frequency of this mutation, 999del5, in 1,182 Icelanders, comprising 520 randomly selected individuals from the population and a series of 632 female breast cancer patients (61.4% of patients diagnosed during the study period) and all male breast cancer patients diagnosed during the past 40 years. We detected the 999del5 germ-line mutation in 0.6% of the population, in 7.7% of female breast cancer patients, and in 40% of males with breast cancer. The mutation was strongly associated with onset of female breast cancer at age <50 years, but its penetrance and expression are varied. A number of cancers other than breast cancer were found to be increased in relatives of mutation carriers, including those with prostate and pancreatic cancer. Furthermore, germ-line BRCA2 mutation can be present without a strong family history of breast cancer. Comparison of the age at onset for mother/daughter pairs with the 999del5 mutation and breast cancer indicates that age at onset is decreasing in the younger generation. Increase in breast cancer incidence and lower age at onset suggest a possible contributing environmental factor.     

Transmission of the human immunodeficiency virus during breast feeding and heterosexual contacts

Two cases of the transfer of HIV infection are described: a child got HIV infection through breast feeding from the mother infected with HIV as the result of blood transfusion made 2 weeks after the birth of the child and 2 men were infected with HIV as the result of sexual relations with a woman found to be a HIV carrier.     

A little help from my friends: caring for premature babies in a war zone

Background

Too much or too little milk production are common problems in a lactation consultant's practice. Whereas underproduction is widely discussed in the lactation literature, overabundant milk supply is not. In my practice I work with women who experience moderate to severe oversupply syndrome. In most cases the syndrome can be successfully treated with full removal of milk followed by unilateral breastfeeding ad lib with the same breast offered at every breastfeed in a certain time block ("block feeding").

Case presentations

Four cases of over-supply of breast milk are presented. The management and outcome of each case is described.

Conclusion

Overabundant milk supply is an often under-diagnosed condition in otherwise healthy lactating women. Full drainage and "block feeding" offer an adequate and userfriendly way to normalize milk production and treat symptoms in both mother and child.     

Nestling sex ratio is associated with both male and female attractiveness in rock sparrows

According to theory, in species in which male variance in reproductive success exceeds that of the females, sons are more costly to produce; females mated with high quality males or those in better condition should produce more sons. In monogamous species, however, the variance in the reproductive success of the two sexes is often similar and mate choice is often mutual, making predictions regarding sex allocation more difficult. In the rock sparrow Petronia petronia, both males and females have a sexually selected yellow patch on the breast, whose size correlates with individual body condition. We investigated whether the brood sex ratio co‐varies with the size of the yellow patch of the father and the mother in a sample of 173 broods (818 chicks) over 8 breeding seasons. While the size of the yellow patch of the mother and the father did not predict per se a deviation from the expected 1:1 sex ratio, brood sex ratios were predicted by the interaction of male and female yellow patch size. This result is surprising, as the ornament is sexually selected by both males and females as an indicator of quality in both sexes and should therefore be inherited by all offspring irrespective of their sex. It indirectly suggests that other sex‐specific traits associated with patch size (e.g. polygyny in males and fecundity in females) may explain the sex allocation bias observed in rock sparrows. Thus, female individual quality alone, as expressed through the size of the yellow patch, was not associated with the biases in sex ratios reported in this study. Our results rather suggest that sex allocation occurs in response to male attractiveness in interaction with female attractiveness. In other words, females tend to preferentially allocate towards the sex of the parent with more developed ornament within the pair.     

Breast-feeding patterns, maternal milk output and lactational infecundity.

Breast feeding can serve as a contraceptive up to 6 months after birth with 98% effectiveness. The so-called suckling reflex arc is a sensitive mechanism conveying messages about nutritional needs of the child, stimulating the release of prolactin responsible for milk production, suppressing ovarian activity by hypothalamic beta-endorphin production leading to reduction in the pulsatile release of gonadotrophic hormones. Increased suckling produces more milk, but only in well-fed women. In Bangladesh, malnourished children required more suckling time than better-fed infants. Increasing the amounts of weaning food lowers feed urgency and suckling intensity thereby relaxing ovarian suppression. Breast-milk consumption can be measured by test weighing the infant before and after feeding, but it is subject to error, especially in developing countries where up to 20 feeds are required to deliver 800 ml of milk. Thus, weighing over 2-5 days is more accurate. The method of giving deuterium oxide tracer to the mother, and measuring its disappearance from the mother's milk and the infant's saliva for 2 weeks is precise and noninvasive. The Doppler ultrasound technique measures milk flow through an artificial teat for research purposes. Manual or mechanical pump measurement of milk transfer separates the mother from the child, thus it is not useful for normal conditions. It can be used for estimating the amount of milk left and the rate of milk secretion by using a breast pump along with oxytocin for full emptying of milk. Accurate estimation of suckling intensity and milk transfer is essential for the determination of the relationship of breast feeding and lactational infecundity.     

Origin of individuality of two daughter cells during the division process examined by the simultaneous measurement of growth and swimming property using an on-chip single-cell cultivation system

We examined the origin of individuality of two daughter cells born from an isolated single Escherichia coli mother cell during its cell division process by monitoring the change in its swimming behavior and tumbling frequency using an on-chip single-cell cultivation system. By keeping the isolated condition of an observed single cell, we compared its growth and swimming property within a generation and over up to seven generations. It revealed that running speed decreased as cell length smoothly increased within each generation, whereas tumbling frequency fluctuated among generations. Also found was an extraordinary tumbling mode characterized by the prolonged duration of pausing in predivisional cells after cell constriction. The observed prolonged pausing may imply the coexistence of two distinct control systems in a predivisional cell, indicating that individuality of daughter cells emerges after a mother cell initiates constriction and before it gets physically separated into two new cell bodies.     

Clinical and pathological characteristics of occult breast cancer and review of the literature

Purpose: Occult breast cancer is defined as axillary metastasis without clinically and/or radiologically evident primary tumor. In female patients presenting with isolated axillary nodes with adenocarcinoma, the most likely primary cancer is an invasive breast carcinoma. Herein we present our experience over this issue, together with a brief review of the literature about this clinically challenging condition. Methods: We retrospectively analyzed 1215 consecutive breast cancer patients treated at our clinic between 2004- 2010. Four of these patients presented with axillary nodal metastasis without clinical and radiological evidence of a primary breast tumor. Results: The incidence of occult breast cancer in our clinic was 0.32%. Median follow-up was 8 months. All patients were alive and remained free of disease at the end of the follow-up period. Conclusion: The prognostic factors for occult breast carcinoma are similar to that of its overt counterpart. The number of axillary lymph node involved and the hormone receptor status are considered significant prognostic predictors. Further studies with randomization and longer followup are needed for the establishment of a safe management plan.     

Breast cancer in a patient with gynecomastia

A case of breast carcinoma in the midst of florid gynecomastia in a 20-year-old man is reported. Up to now, only two male patients under the age of 21 with breast malignancy have been described in the literature. In contrast, gynecomastia is a more common condition than generally appreciated. The association of gynecomastia, a rather common condition, and cancer of the male breast, a rather uncommon condition, is examined. Mammography is recommended as part of the workup. A new classification of gynecomastia into true, pseudo, and mixed types is suggested. Recommendations for the role of lipoplasty in the treatment of gynecomastia are made.     

Managing Bone Health in Breast Cancer

ObjectiveOsteoporosis is a common condition that can be caused or exacerbated by estrogen deficiency.MethodsThis narrative review will discuss optimizing bone health in the setting of adjuvant endocrine treatments for hormone receptor–positive breast cancer and the current use of antiresorptive agents as adjuvant therapy and as bone modifying agents.ResultsAdjuvant endocrine treatments for hormone receptor–positive breast cancer (tamoxifen and aromatase inhibitors) affect bone health. The exact effect depends on the agent used and the menopausal state of the woman. Antiresorptive medications for osteoporosis, bisphosphonates and denosumab, lower the risk of bone loss from aromatase inhibitors. Use of bisphosphonates as adjuvant treatment in breast cancer, regardless of hormone receptor status, is increasing because of benefits seen to cancer relapse and survival.ConclusionOptimizing bone health in women with breast cancer during and after cancer treatment is informed by an understanding of breast cancer treatment and its skeletal effect.     

Stable correlation structure among multiple plumage colour traits: can they work as a single signal?

The presence of multiple distinct ornamental traits in the same species is frequently explained by context‐specificity and different information content. However, the expression of multiple ornaments is often correlated, and such traits may therefore function as a single, integrated signal. Delayed use of an integrated signal relative to production requires temporal stability in integration, which has seldom been examined. We used autumn and spring reflectance data from the breast, breast stripe, and crown of great tits (Parus major) to assess the stability and mating implications of colour signal integration, as well as the repeatability of any integrated colour trait and its correlation with condition during moult. We found high levels of stability between seasons, years, sexes, and ages in the correlation patterns of colour measures across the three plumage areas. The first principal component colour axis described joint variation of ultraviolet (UV) reflectance on the crown and the breast stripe, thereby representing an among‐trait UV chroma axis. However, only breast yellow chroma showed condition‐dependence, whereas temporally consistent and significant assortative mating was restricted to crown UV chroma. Our results therefore do not support the idea that the overall UV chroma of the breast stripe and the crown is special in condition‐dependence and repeatability, or that it plays a specific role in mutual sexual selection as an integrated signal. The results show that stable association between display traits is an existing phenomenon. They also indicate that, even in the presence of correlated traits, functional trait integration among these requires further scrutiny. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 114 , 92–108.     

Fatty acid composition of human milk in Kuwaiti mothers

Kuwaiti diet is exceptionally rich in fat, carbohydrates and proteins. In addition, subjects in Kuwait are exposed to extreme heat and sun light. Fatty acid profiles of human milk obtained from 19 full breast feeding Kuwaiti mothers were analyzed. Dietary patterns for individual mothers were determined by 24 h dietary recall and food frequency questionnaire. The fatty acid content of human milk was affected by the diet consumed by the lactating mother. The content of long chain polyunsaturated fatty acids (LCP) in human milk lipids did not correlate with their parent fatty acids like linoleic and alpha-linolenic acids. However the human milk LCP were related to the of content of LCP in the maternal diet. Mothers reporting a high fish consumption showed significant amounts of C22:6, omega 3 and C20:5, omega 3 fatty acids. As a general conclusion, breast milk produced by a well nourished mother is better suited to meet the lipid requirements of infants.     

Social influence on sexual maturation and breeding in the female Mongolian gerbil (Meriones unguiculatus)

Social factors influencing reproductive activity in laboratory groups of gerbils were investigated using the ventral scent-gland as an index of reproductive condition. Sexual maturation and breeding were suppressed in female offspring remaining with their parents. In family groups living in enclosures, daughters rarely bred in the presence of their mother but breeding activity increased after death. Intra-female aggression resulted in the re-establishment of a single breeding female in groups where more than one started to breed. In a controlled social situation in which females were caged with their mothers, sexual maturation was suppressed in the presence of their mother and the continuing presence of her second litter, but not in the presence of a non-pregnant mother or a mother whose second litter had been removed.     

Melanin-based coloration is a nondirectionally selected sex-specific signal of offspring development in the alpine swift

Two mutually exclusive hypotheses have been put forward to explain the evolution and adaptive function of melanin-based color traits. According to sexual selection theory melanism is a directionally selected signal of individual quality, whereas theory on the maintenance of genetic polymorphism proposes that alternative melanin-based variants achieve equal fitness. Alpine swift (Apus melba) males and females have a conspicuous patch of white feathers on the breast with their rachis varying continuously from white to black, and hence the breast varies from white to striated. If this trait is a sexually selected signal of quality, its expression should be condition dependent and the degree of melanism directionally selected. If variation in melanism is a polymorphism, its expression should be genetically determined and fitness of melanin-based variants equal. We experimentally tested these predictions by exchanging eggs or hatchlings between randomly chosen nests and by estimating survival and reproduction in relation to melanism. We found that breast melanism is heritable and that the environment and body condition do not significantly influence its expression. Between 5 and 50 days of age nestlings were heavier and their wings longer when breast feathers of their biological father were blacker, and they also fledged at a younger age. This shows that aspects of offspring quality covary positively with the degree of melanism. However, this did not result in directional selection because nestling survival and recruitment in the local breeding population were not associated with father breast melanism. Furthermore, adult survival, age at first reproduction and probability of skipping reproduction did not covary with the degree of melanism. Genetic variation in breast melanism is therefore maintained either because nonmelanic males achieve fitness similar to melanic males via a different route than producing fast-growing offspring, or because the advantage of producing fast-growing offspring is not sufficiently pronounced to result in directional selection.     

Analysis of centrosome localization of BRCA1 and its activity in suppressing centrosomal aster formation

BRCA1, a product of a familial breast and ovarian cancer susceptibility gene, localizes to centrosomes and physically interacts with γ-tubulin, a key centrosomal protein for microtubule nucleation and anchoring at centrosomes. Here, we performed a rigorous analysis of centrosome localization of BRCA1, and found that BRCA1 is specifically associated with mother centrioles in unduplicated centrosomes, and daughter centrioles acquire BRCA1 prior to initiation of duplication, and thus duplicated centrosomes are both bound by BRCA1. We further found that BRCA1 suppresses centrosomal aster formation. In addition, we identified a new domain of BRCA1 critical for γ-tubulin binding, which confers not only its localization to centrosomes, but also its activity to suppress centrosomal aster formation.     

An experimental study on the self-reference effect

Self-reference at encoding increases the probability of recollective experience in recognition memory. Self-reference effect (SRE) in memory is observed when the degree of self-reference of to-be-remembered materials is varied. Usually items encoded in terms of self-reference are associated with significantly higher recall performance relative to items encoded in other ways, including semantic encoding. In our three experiments, four orientating tasks formed four levels in a between-subjects design. The conditions were rating personality traits with reference to self, mother, Lu Xun (a famous Chinese writer) or rating the traits on a negative-positive dimension. In a recognition test, subjects first identified old items and then indicated which of these were accompanied by recollective experience ('remember' responses) and which were recognized on some other basis ('know' responses). Our results showed that both the self-reference condition and mother condition were associated with the same highest propo     

16q22.1 microdeletion detected by array-CGH in a family with mental retardation and lobular breast cancer

We describe the case of a boy with psychomotor delay and dysmorphic features, with a germline 16q22.1 microdeletion identified by array-CGH. The deletion spans 0.24Mb and encompasses three genes (ZFP90, CDH3 and CDH1). The deletion has been demonstrated to be inherited from his mother who was affected by lobular breast cancer (LBC) without any other apparently phenotypic features. We suppose that the microdeletion, in particular ZFP90 which is cerebrally expressed, is causative for the boy's phenotype. Mental retardation in the affected boy can recognize several mechanisms such as variable expressivity, non-penetrance, multifactorial/polygenic inheritance, recessive inheritance, a second rearrangement event and epigenetics. Furthermore, we suggest that the deletion of the CDH1, a tumor suppressor gene, involved in hereditary diffuse gastric cancer (HDGC) and LBC predisposed the mother to the carcinoma.