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PubMed2004

The optimal duration of exclusive breastfeeding: a systematic review.

Although the health benefits of breastfeeding are acknowledged widely, opinions and recommendations are divided on the optimal duration of exclusive breastfeeding. We systematically reviewed available evidence concerning the effects on child health, growth, and development and on maternal health of exclusive breastfeeding for 6 months vs. exclusive breastfeeding for 3-4 months followed by mixed breastfeeding (introduction of complementary liquid or solid foods with continued breastfeeding) to 6 months. Two independent literature searches were conducted, together comprising the following databases: MEDLINE (as of 1966), Index Medicus (prior to 1966), CINAHL, HealthSTAR, BIOSIS, CAB Abstracts, EMBASE-Medicine, EMBASE-Psychology, Econlit, Index Medicus for the WHO Eastern Mediterranean Region, African Index Medicus, Lilacs (Latin American and Carribean literature), EBM Reviews-Best Evidence, the Cochrane Database of Systematic Reviews, and the Cochrane Controlled Trials Register. No language restrictions were imposed. The two searches yielded a total of 2,668 unique citations. Contacts with experts in the field yielded additional published and unpublished studies. Studies were stratified according to study design (controlled trials vs. observational studies) and provenance (developing vs. developed countries). The main outcome measures were weight and length gain, weight-for-age and length-for-age z-scores, head circumference, iron status, gastrointestinal and respiratory infectious morbidity, atopic eczema, asthma, neuromotor development, duration of lactational amenorrhea, and maternal postpartum weight loss. Twenty independent studies meeting the selection criteria were identified by the literature search: 9 from developing countries (2 of which were controlled trials in Honduras) and 11 from developed countries (all observational studies). Neither the trials nor the observational studies suggest that infants who continue to be exclusively breastfed for 6 months show deficits in weight or length gain, although larger sample sizes would be required to rule out modest increases in the risk of undernutrition. The data are conflicting with respect to iron status but suggest that, at least in developing-country settings, where iron stores of newborn infants may be suboptimal, exclusive breastfeeding without iron supplementation through 6 months of age may compromise hematologic status. Based primarily on an observational analysis of a large randomized trial in Belarus, infants who continue exclusive breastfeeding for 6 months or more appear to have a significantly reduced risk of one or more episodes of gastrointestinal tract infection. No significant reduction in risk of atopic eczema, asthma, or other atopic outcomes has been demonstrated in studies from Finland, Australia, and Belarus. Data from the two Honduran trials suggest that exclusive breastfeeding through 6 months of age is associated with delayed resumption of menses and more rapid postpartum weight loss in the mother. Infants who are breastfed exclusively for 6 months experience less morbidity from gastrointestinal tract infection than infants who were mixed breastfed as of 3 or 4 months of age. No deficits have been demonstrated in growth among infants from either developing or developed countries who are exclusively breastfed for 6 months or longer. Moreover, the mothers of such infants have more prolonged lactational amenorrhea and faster postpartum weight loss. Based on the results of this review, the World Health Assembly adopted a resolution to recommend exclusive breastfeeding for 6 months to its member countries. Large randomized trials are recommended in both developed and developing countries to ensure that exclusive breastfeeding for 6 months does not increase the risk of undernutrition (growth faltering), to confirm the health benefits reported thus far, and to investigate other potential effects on health and development, especially over the long term.

Breast Feeding↗

PubMed1987

Muscle and blood ammonia and lactate responses to prolonged exercise with hyperoxia.

Investigations using nonsteady-state and fatiguing exercise protocols have demonstrated a strong relationship between ammonia and lactate metabolism and have suggested a cause and effect relationship between these two variables. We investigated the lactate-ammonia response using prolonged exercise and inspiration of hyperoxic gas (60% O2-40% N2). The exercise consisted of either 70-75% maximal O2 uptake (VO2 max) for 40 min (series 1, n = 6) or 75-80% VO2max for 30 min (series 2, n = 6) with the subjects inspiring room air on one occasion and hyperoxia in the other test. In both series blood ammonia rose continuously throughout the exercise regardless of the inspired gas treatment; in contrast blood lactate did not increase after 10 min with room air, and with hyperoxia blood lactate was reduced. Muscle lactate and ammonia (series 2; vastus lateralis) had responses similar to the blood data. The data demonstrated no apparent lactate-ammonia relationship with prolonged exercise or in response to hyperoxia, suggesting that ammonia production can be independent of lactate metabolism. The data also suggest that type I fibers can be a major source of ammonia in humans.

Adult↗

PubMed2002

Optimal duration of exclusive breastfeeding.

BACKGROUND: : Although the health benefits of breastfeeding are widely acknowledged, opinions and recommendations are strongly divided on the optimal duration of exclusive breastfeeding. Much of the debate has centered on the so-called 'weanling's dilemma' in developing countries: the choice between the known protective effect of exclusive breastfeeding against infectious morbidity and the (theoretical) insufficiency of breast milk alone to satisfy the infant's energy and micronutrient requirements beyond four months of age. The debate over whether to recommend exclusive breastfeeding for four to six months versus 'about six months' has recently become heated and acrimonious. OBJECTIVES: : The primary objective of this review was to assess the effects on child health, growth, and development, and on maternal health, of exclusive breastfeeding for six months versus exclusive breastfeeding for three to four months with mixed breastfeeding (introduction of complementary liquid or solid foods with continued breastfeeding) thereafter through six months. A secondary objective was to assess the child and maternal health effects of prolonged (greater than six months) exclusive breastfeeding versus exclusive breastfeeding for six months followed by mixed breastfeeding thereafter. SEARCH STRATEGY: : Two independent literature searches were carried out, together comprising the following databases: MEDLINE (as of 1966), Index Medicus (prior to 1966), CINAHL, HealthSTAR, BIOSIS, CAB Abstracts, EMBASE-Medicine, EMBASE-Psychology, Econlit, Index Medicus for the WHO Eastern Mediterranean Region, African Index Medicus, Lilacs (Latin American and Caribbean literature), EBM Reviews-Best Evidence, the Cochrane Database of Systematic Reviews (The Cochrane Library Issue 3, 2000), and the Cochrane Controlled Trials Register (The Cochrane Library Issue 3, 2000). No language restrictions were imposed. The two searches yielded a total of 2,668 unique citations. Contacts with experts in the field yielded additional published and unpublished studies. SELECTION CRITERIA: : We selected all internally-controlled clinical trials and observational studies comparing child or maternal health outcomes with exclusive breastfeeding for six or more months versus exclusive breastfeeding for at least three to four months with continued mixed breastfeeding until at least six months. Studies were stratified according to study design (controlled trials versus observational studies), provenance (developing versus developed countries), and timing of compared feeding groups (three to seven months versus later). DATA COLLECTION AND ANALYSIS: : Two reviewers independently assessed study quality (using a priori assessment criteria) and extracted data. MAIN RESULTS: : Twenty independent studies meeting the selection criteria were identified by the literature search: nine from developing countries (two of which were controlled trials in Honduras) and 11 from developed countries (all observational studies). The two trials did not receive high methodologic quality ratings but were nonetheless superior to any of the observational studies included in this review. The observational studies were of variable quality; in addition, their nonexperimental designs were not able to exclude potential sources of confounding and selection bias. Definitions of exclusive breastfeeding varied considerably across studies. Neither the trials nor the observational studies suggest that infants who continue to be exclusively breastfed for six months show deficits in weight or length gain, although larger sample sizes would be required to rule out modest differences in risk of undernutrition. The data are conflicting with respect to iron status, but at least in developing country settings where newborn iron stores may be suboptimal, suggest that exclusive breastfeeding without iron supplementation through six months may compromise hematologic status. Based primarily on an observational analysis of a large randomized trial in Belarus, infants who continue exclusive breastfeeding for six months or more appear to have a significantly reduced risk of one or more episodes of gastrointestinal infection. No significant reduction in risk of atopic eczema, asthma, or other atopic outcomes has been demonstrated in studies from Finland, Australia, and Belarus. Data from the two Honduran trials suggest that exclusive breastfeeding through six months is associated with delayed resumption of menses and more rapid postpartum weight loss in the mother. REVIEWER'S CONCLUSIONS: : We found no objective evidence of a 'weanling's dilemma'. Infants who are exclusively breastfed for six months experience less morbidity from gastrointestinal infection than those who are mixed breastfed as of three or four months, and no deficits have been demonstrated in growth among infants from either developing or developed countries who are exclusively breastfed for six months or longer. Moreover, the mothers of such infants have more prolonged lactational amenorrhea. Although infants should still be managed individually so that insufficient growth or other adverse outcomes are not ignored and appropriate interventions are provided, the available evidence demonstrates no apparent risks in recommending, as a general policy, exclusive breastfeeding for the first six months of life in both developing and developed country settings. Large randomized trials are recommended in both types of setting to rule out small effects on growth and to confirm the reported health benefits of exclusive breastfeeding for six months or beyond.

Breast Feeding↗

PubMed2003

Life history and the competitive environment: trajectories of growth, maturation, and reproductive output among chacma baboons.

The social environment is a key feature influencing primate life histories. Chacma baboons (Papio hamadryas ursinus) are a female-bonded species with a strict linear dominance hierarchy. In this species, the allocation of energy to competing demands of growth and reproduction is hypothesized to vary as a function of competitive ability, which in turn increases with social rank. Since growth rate is a major component of life history models, measures of age-specific growth were used to analyze variation in life history traits across social ranks. Weights of 42 immature baboons were obtained without sedation or baiting from a troop of well-habituated chacma baboons in the Okavango Delta, Botswana. Using demographic and weight data from this wild population, five main findings emerged: 1) Weight for age and growth rate of infant and juvenile females are positively associated with maternal rank. 2) Male growth is not influenced by maternal rank. 3) Female growth shows smaller variation across feeding conditions than male growth. 4) Low-ranking adult females continue investment in offspring through prolonged lactation until they reach a weight comparable to that of high-ranking infants. 5) The benefit of rank to reproductive success shown in this study is 0.83 additional offspring. Reproductive span determined predominantly by age at maturation contributes 27-38% to the difference in expected number of offspring by rank, vs. 62-73% due to reproductive rate. These findings have major implications for understanding the role of social environment in phenotypic plasticity of life history traits, and in the evolution of primate life histories.

Animals↗

PubMed2003

Paracrine interactions of mammalian adipose tissue.

Adipose tissue develops in and/or around most lymphoid tissues in mammals and birds. Early reports of this widespread association and hypotheses for its functional basis were long ignored in the planning of in vitro studies and the interpretation of in vivo results. Biochemical studies on rodent tissues reveal many site-specific properties of adipocytes anatomically associated with lymph nodes and omental milky spots that equip them to interact locally with lymphoid cells. The paracrine interactions are strongest for the most readily activated lymph nodes and are modulated by dietary lipids. Perinodal adipocytes contribute less than those in the large nodeless depots to whole-body lipid supplies during fasting. Observations on wild animals show that perinodal adipose tissue is selectively conserved even in starvation but does not enlarge greatly in natural obesity. Such paracrine provisioning of peripheral immune responses improves their efficiency and emancipates activated lymphocytes from competition with other tissues for blood-borne nutrients. The relationship is found in extant protherians and metatherians, so it almost certainly arose early in the evolution of mammals, possibly as part of the metabolic reorganisation associated with homeothermy, viviparity, and lactation. Prolonged disruption to paracrine interactions between lymphoid and adipose tissue may contribute to the HIV-associated adipose redistribution syndrome, causing selective hypertrophy of the mesentery, omentum, and other adipose depots that contain much activated lymphoid tissue. Skeletal and cardiac muscle may also have paracrine relationships with anatomically associated adipose tissue, but interactions between contiguous tissues have not been demonstrated directly.

Adipose Tissue↗

PubMed1975

Nature of muscular change in osteomalacia: light- and electron-microscope observations.

Thirteen muscle biopsy specimens (mainly the gluteus maximus) from 12 patients with laboratory confirmation of osteomalacia and proximal muscle weakness in 10 were examined by light and electron microscopy. Light microscopy revealed mild diffuse non-specific atrophy of the muscle fibres in 10 cases, severe generalised atrophy in one and patchy group atrophy in one. There was no myopathic change in specimens from cases with either a nutritional aetiology, or a mixed aetiology. The former, mostly women gave a history of severe chronic malnutrition often accompanied by repeated pregnancies and prolonged lactation; those with a mixed aetiology gave, in addition, evidence of a metabolic or endocrine disorder such as hyperparathyroidism, hyperthyroidism, uraemia, or treatment with anti-epileptic drugs or were of uncertain origin. Electron-microscope examination of muscle from the nutritional group showed atrophic changes in the fibres, such as loss of myofibrils, prominence of mitochondria and glycogen, loosening and folding of the basement-membrane but good preservation of the remaining myofibrils. In contrast muscle from cases of mixed aetiology showed, in addition to the atrophic features, clear degenerative changes in the myofibrils and the mitochondria, accumulation of amorphous material at the site of myofibrillar loss and of lipofuscin in muscle fibres, vascular endothelium and satellite cells. The earliest degenerative change was in the "I" band, involving actin filaments and "Z" line. The triads were generally preserved but the sarcoplasmic reticulum appeared affected in a patient with tetany and severe mitochondrial degeneration. In a patient with thyrotoxicosis, proliferation of central nuclei, "Z" line streaming and formation of "T" tubular aggregates were seen. In one patient with hyperparathyroidism and hypercalcaemia, severe myofibrillar degeneration and mitochondria showing osmiophilic deposits, possibly of calcium phosphate, were encountered. It is concluded: (1) that all osteomalacic muscle weakness is not myopathic but a non-specific atrophy occurring probably on the basis of disuse and malnutrition, and (2) patients with an added metabolic or endocrinological disorder show in addition to the atrophy, degenerative changes in the muscle fibre and its sub-cellular components consistent with myopathy, and these patients should be clearly distinguished from those with a background of malnutrition only.

Adolescent↗

PubMed1982

Influence of breast-feeding pattern on pituitary-ovarian axis of women in an industrialized community.

A longitudinal study of 48 postpartum women showed that during the first 6 months the daily frequency of infant feedings remained between six and seven. The lower threshold of the ratio breast-feedings/supplementary feedings that sustained both hyperprolactinemia and anovulation was 4.5/1. The duration and the 24-hour distribution, but not the intensity, of breast-feedings were significantly altered during prolonged lactation and when supplementary feeding was used. However, neither differences in the levels of prolactin (PRL) no gonadal status could be correlated with qualitative differences in the breast-feeding pattern. Postpartum maternal body weight was not related to serum PRL, gonadotropins, or resumption of ovulation, but mothers who smoked cigarettes had significantly lower serum levels of PRL during the third and fourth months, and weaned their babies earlier, than did mothers who were nonsmokers. Our data showed that minor quantitative differences in the feeding pattern have a significant impact on the pituitary-gonadal axis, and that the decline in the levels of PRL during continued lactation is due mainly to a decreased frequency of breast-feeding but may be due also to a shorter duration and more heterogeneous 24-hour distribution of nursings but not to a reduced intensity of sucking.

Adult↗

PubMed1985

Studies on reproduction in rats with meclofenamate sodium, a nonsteroidal anti-inflammatory agent.

Reproduction and teratology studies were performed in rats given meclofenamate sodium, a nonsteroidal anti-inflammatory agent. Dosages of 0, 3, 6, and 9 mg/kg were administered orally as dietary admixtures in the Fertility and Perinatal-Postnatal studies. In the Teratology study, dosages of 10, 12, 15, and 20 mg/kg were administered by intragastric intubation. In the Male-Fertility study no adverse effects on fertility or litter and offspring parameters were observed in two generations. In the Female-Fertility and Perinatal-Postnatal studies, maternal toxicity (death associated with intestinal ulceration and adhesions) was particularly evident during lactation. Prolonged gestation periods, decreased weanling weights, and increased weanling mortality were evident at dosages of 6 and 9 mg/kg. Increased postimplantation loss occurred at 6 and 9 mg/kg in the Term Sacrifice subgroup of the Female-Fertility study. Fertility rates were unaffected and all other litter and offspring parameters of the F1 and F2 generations appeared normal. In the Teratology study no adverse effects on embryonic or fetal development were evident at maternally toxic dosages up to 20 mg/kg.

Abnormalities, Drug-Induced↗

PubMed1987

Historical review of the changing pattern of infant feeding in developing countries: the case of Malaysia, the Caribbean, Nigeria and Zaire.

Prolonged lactation and early supplementation have been traditional practices among low-income mothers in Malaysia, the Caribbean, Nigeria and Zaire. Early supplementation is still the norm but there have been some substantial changes in the types of supplement offered. Thus, except in Zaire, there is now widespread use of processed milks as supplements for very young infants. The use of processed milks began in the 1920s in Malaysia and the Caribbean, but not until the 1960s in Nigeria. Processed milks are, as yet, rarely used in Zaire. The use of processed milks has not, however, led to the abandonment of traditional paps. The latter are still given as supplements to young infants in Nigeria and to older infants in Malaysia and the Caribbean. Breast-feeding duration has declined in Malaysia and the Caribbean although initiation is almost universal. In Nigeria and Zaire most low-income mothers continue to breast-feed for at least 12 months. The changes in the types of supplements used and in breast-feeding duration are analogous to the changes observed in industrialised countries from the mid-19th century, and many of the associated factors are similar: urbanisation; female participation in the labour force; increased availability of processed milks and their promotion both by companies and the health sector; and the regimentation of breast-feeding. This review highlights the negative role played by the health sector in the past, and discusses its future role in promoting and supporting breast-feeding.

Breast Feeding↗

PubMed2000

Food allergy and nutrition in early life: implications for later health.

Allergic diseases are a common cause of illness in most industrialized countries. Diet during early childhood is an important determinant of the development of allergy, particularly in high-risk infants who have a parental history of atopy. Maternal avoidance of highly-allergenic foods during pregnancy and lactation, prolonged exclusive breast-feeding, the use of a hydrolysed milk formula, and delayed introduction of dairy products, eggs, fish, nuts and soybean are associated with a lower incidence of allergic symptoms and signs. These beneficial effects are observed for as long as 18 years of age. Similarly, nutrition and physical growth are important factors that influence immunocompetence and morbidity due to infections. Small-for-gestational age low-birth-weight infants show prolonged impairment of cell-mediated immunity, antibody responses and phagocyte function. Recent studies indicate the beneficial effect of moderate amounts of Zn given in the first 6 months of life. Thus, diet and nutrition in early life are crucial for the development of allergic and infectious disease throughout childhood and into adulthood.

Adolescent↗

PubMed2002

Complexities in ETS-domain transcription factor function and regulation: lessons from the TCF (ternary complex factor) subfamily. The Colworth Medal Lecture.

The ETS-domain transcription factor family can be divided into a series of subfamilies. Elk-1 represents the founding member of the ternary complex factor (TCF) subfamily. By focusing on the TCF subfamily, we can demonstrate the complexities that exist in the function and regulation of ETS-domain transcription factors. This article focuses on Elk-1 in detail and summarizes the functions of other TCFs. The key themes covered include the domain structure of the TCFs, the mechanisms of complex formation with serum response factor, regulation of TCFs by mitogen-activated protein kinase cascades, and transcriptional regulatory properties of the TCFs. Finally, the emerging role of the TCFs in vivo is discussed. A picture is developing indicating that, while these proteins exhibit significant sequence and functional conservation, key differences in their structure and regulation are being identified which may relate to unique functions of these proteins in vivo.

Amino Acid Sequence↗

PubMedDate not supplied

Lactic acid buffering by bone and shell in anoxic softshell and painted turtles.

We tested two hypotheses: first, that the inferior anoxia tolerance of the softshell turtle, Apalone spinifera, compared to the western painted turtle, Chrysemys picta bellii, is related to its less mineralized shell, and second, that turtle bone, like its shell, stores lactate during prolonged anoxia. Lactate concentrations of blood, hindlimb bone, and shell were measured on normoxic Apalone and Chrysemys and after anoxic submergence at 10 degrees C for 2 and 9 d, respectively. Blood and shell concentrations of Ca(2+), Mg(2+), Na(+), K(+), and inorganic phosphate (P(i); for shell only) were also measured. Because a preliminary study indicated lactate distribution in Chrysemys throughout its skeleton during anoxia at 20 degrees C, we used hindlimb bones as representative skeletal samples. Apalone shell, though a similar percentage of body mass as Chrysemys shell, had higher water content (76.9% vs. 27.9%) and only 20%-25% as much Ca(2+), Mg(2+), CO(2), and P(i). When incubated at constant pH of 6.0 or 6.5, Apalone shell powder released only 25% as much buffer per gram wet weight as Chrysemys shell. In addition, plasma [Ca(2+)] and [Mg(2+)] increased less in Apalone during anoxia at an equivalent plasma lactate concentration. Lactate concentrations increased in the shell and skeletal bone in both species. Despite less mineralization, Apalone shell took up lactate comparably to Chrysemys. In conclusion, a weaker compensatory response to lactic acidosis in Apalone correlates with lower shell mineralization and buffer release and may partially account for the poorer anoxia tolerance of this species.

Acidosis, Lactic↗

PubMed1995

Seasonal variation in human reproduction: environmental factors.

Almost all human populations exhibit seasonal variation in births, owing mostly to seasonal variation in the frequency of conception. This review focuses on the degree to which environmental factors like nutrition, temperature and photoperiod contribute to these seasonal patterns by acting directly on the reproductive axis. The reproductive strategy of humans is basically that of the apes: Humans have the capacity to reproduce continuously, albeit slowly, unless inhibited by environmental influences. Two, and perhaps three, environmental factors probably act routinely as seasonal inhibitors in some human populations. First, it seems likely that ovulation is regulated seasonally in populations experiencing seasonal variation in food availability. More specifically, it seems likely that inadequate food intake or the increased energy expenditure required to obtain food, or both, can delay menarche, suppress the frequency of ovulation in the nonlactating adult, and prolong lactational amenorrhea in these populations on a seasonal basis. This action is most easily seen in tropical subsistence societies where food availability often varies greatly owing to seasonal variation in rainfall; hence births in these populations often correlate with rainfall. Second, it seems likely that seasonally high temperatures suppress spermatogenesis enough to influence the incidence of fertilization in hotter latitudes, but possibly only in males wearing clothing that diminishes scrotal cooling. Since most of our knowledge about this phenomenon comes from temperate latitudes, the sensitivity of spermatogenesis in both human and nonhuman primates to heat in the tropics needs further study. It is quite possible that high temperatures suppress ovulation and early embryo survival seasonally in some of these same populations. Since we know less than desired about the effect of heat stress on ovulation and early pregnancy in nonhuman mammals, and nothing at all about it in humans or any of the other primates, this is an important area for future research. Third, correlational data suggest that there may be some degree of regulation of reproduction by photoperiod in humans at middle to higher latitudes. Populations at these latitudes often show a peak in presumed conceptions associated with the vernal equinox. On the other hand, evidence gathered by neuroendocrinologists tends to argue against reproductive photoresponsiveness in humans.

Animals↗

PubMed2000

Does hypoxia impair ovarian function in Bolivian women indigenous to high altitude?

Fertility appears to be reduced in at least some high altitude populations relative to their counterparts at lower elevations. Inferring from the difficulties with reproduction of newcomers to high altitude and from animal experiments, it has been hypothesized that this apparent reduction is the result of hypoxia acting to reduce fecundity and/or increase fetal loss. In humans, however, several behavioral as well as biological factors may affect fertility levels. These many factors have been organized by demographers into a framework of seven proximate determinants that includes fecundability (the monthly probability of conception) of which successful ovulation is one component. To test whether ovarian function is impaired in women indigenous to high altitude, we measured salivary progesterone (P) in a sample (n = 20) of Quechua women (aged 19-42 years) residing at 3,100 m. It was found that mean luteal P = 179 pmol/L and mean midluteal P = 243 pmol/L, levels that fall about midway in the range of known values for several populations and are higher than some lower altitude populations. These findings suggest that hypoxia does not appear to significantly impair ovarian function in those with lifelong residence at high altitude. There are, however, several factors common to many high altitude populations that may act to reduce fecundability and fertility including intercourse patterns (affected by marriage and migration practices), prolonged lactation, dietary insufficiency, and hard labor.

Adult↗

PubMed1996

p53 protein overexpression in relation to risk factors for breast cancer.

To investigate whether breast tumors developing through a pathway with p53 protein overexpression (p53+) show different risk factor associations compared with breast tumors without p53 overexpression (p53-), the authors determined p53 overexpression in tissue sections of 528 patients with invasive breast cancer by using immunohistochemistry. These patients and 918 healthy controls aged 20-54 years participated in a Netherlands population-based case-control study on oral contraceptives in 1986-1989. A total of 142 tumors (27%) demonstrated clear p53 overexpression (p53+). Most risk factors did not show different associations with p53+ and p53- tumors. However use of oral contraceptives for 9 or more years was associated with a 2.5-fold increase in the risk of p53+ tumors (95% confidence interval 1.4-4.4; test for trend with months of use, p = 0.01), whereas such use increase the risk of p53- tumors only 1.4-fold (95% confidence interval 0.9-2.1; test for trend p = 0.06). Prolonged lactation > or = 25 weeks) was associated with a 40% reduction in risk of p53+ tumors (odds ratio = 0.6; 95%, confidence interval 0.3-1.0; test for trend with weeks of lactation, p = 0.09), whereas the risk of p53- tumors was not associated with lactation. The authors conclude that p53+ and p53- breast tumors are not associated with very distinct risk profiles but that the stronger associations of p53+ tumors with oral contraceptive use and lactation suggest differences in risks that deserve further investigation. If these findings can be confirmed and possible molecular mechanisms explored, this may help to elucidate the associations between these risk factors and breast cancer in general.

Adult↗

PubMed1994

Hartnup disease presenting in an adult.

A young woman presented with pellagra. Her symptoms were precipitated by prolonged lactation and increased activity. Dietary intake of niacin was within recommended guidelines. Chromatography of urinary amino acids was diagnostic of Hartnup disease, an inherited disorder usually presenting in childhood. Her symptoms resolved with oral nicotinamide.

Adult↗

PubMed2005

Immunohistochemical localization of gastrin-releasing peptide, neuronal nitric oxide synthase and neurone-specific enolase in the uterus of the North American opossum, Didelphis virginiana.

The present study has demonstrated the immunohistochemical localization of gastrin-releasing peptide (GRP), neuronal nitric oxide synthase (nNOS) and neurone-specific enolase (NSE) in the uterus of the North American opossum. Although the presence of GRP, nNOS and NSE has been reported recently in the uterus of eutherian species this is the first description of these peptides in a metatherian species. Metatherian mammals are of interest because in these species it is the prolonged lactation phase of development that is the period of primary reproductive investment rather than intrauterine development as is true of eutherian mammals. The opossum, like other marsupial species, has a very abbreviated gestation period which in Didelphis lasts only 12.5 days. GRP was localized in the cytoplasm of cells forming the surface lining epithelium and the glandular epithelium of the opossum endometrium late in pregnancy, at 11.5 days of gestation. Likewise, immunoreactivities of nNOS and NSE were found primarily within the epithelial cells of the endometrium at 11.5 days of gestation. As these peptides and enzymes appear primarily at the time of establishment of the yolk sac placenta (between day 10 and day 12.5 gestation), the present results strongly suggest that these factors may play a fundamental role in the placentation of the opossum.

Animals↗

PubMed1999

History of arthritis and bone rarefaction evidence from paleopathology onwards.

Review of medical and archaeological papers reveals that osteoarthritis has been common in humans and hominids since Paleolithic times. In the British Isles, there was a particularly high prevalence in remains from Romano-British and Saxon burials suggesting that, whatever genetic factors there may have been, there was an extremely high level of physical activity. The prevalence of the condition was lower in late Medieval times; and, in at least one study of subjects from the 18th and 19th centuries, lower than in the current population. In early times, there was a reduction in bone density when there was a change from hunter gathering to agriculture which may have resulted from a change physical activity. Severe cases of osteoporosis have been identified from individual skeletons dated to the Bronze Age. In the Early Medieval period of Nubia there was progressive bone loss in women. Multiple pregnancy, prolonged lactation and dietary deficiency may have been factors. Though women from the 18th and 19th centuries experienced post-menopausal bone loss, this was not as severe as in the present day.

Ancient Lands↗