Extending lactational amenorrhoea in Manila: a successful breast-feeding education programme.

An experimental breast-feeding education programme conducted at the Philippine General Hospital in Manila demonstrated that women could be motivated to improve their breast-feeding practices and lengthen their period of lactational amenorrhoea in comparison to a control group. Mothers who participated in the programme breast-fed their babies more frequently, delayed the introduction of regular supplements, used fewer bottles and pacifiers and maintained night feeding longer than mothers who were not exposed to the positive breast-feeding messages. The programme was successful in lengthening the period of amenorrhoea among women with elementary, high school, or technical school education, but not among college-educated women. Different educational approaches may be necessary for women of different education levels.     

Variability of breast sucking, associated milk transfer and the duration of lactational amenorrhoea.

Quantitative relationships between physical parameters of sucking, milk transfer and the duration of amenorrhoea were examined in normal mother-baby pairs under exclusive breastfeeding. Sucking pressures were recorded twice on the second and once on the fifth month after birth, during complete breastfeeding episodes, by means of a catheter attached to the nipple and connected to a pressure transducer, the signals of which were analysed by computer. Babies were weighed before and after each sucking episode to estimate milk transfer. In the first nursing episode after noon, 2-month-old babies sucked from 140 to > 800 times during 4-15 min from the first breast, obtaining from 20 to > 100 g milk. The physical parameters of sucking and milk transfer exhibited high inter-individual but low intra-individual variabilities. There were significant differences in the physical parameters of sucking and milk transfer efficiency between first and second breast and between the second and fifth months after birth. Milk transfer efficiency was inversely correlated with time occupied by non-sucking pauses > or = 1.5 s, and was directly correlated with mean intersuck intervals in the first breast and with duration of the sucking episode, number of sucks, mean pressure and area under the pressure curve in the second breast. There was no correlation between the physical parameters of sucking and duration of lactational amenorrhoea (n = 62). However, significantly more mothers had amenorrhoea lasting > 180 days among those whose babies spent a longer proportion of the nursing episode in non-sucking pauses > or = 1.5 s. This finding indicates that sensory stimulation of the nipple produced during a nursing episode by stimuli other than sucking itself may have an important role in sustaining lactational amenorrhoea. It is concluded that nursing episodes have a complex structure that allows the development of a breastfeeding phenotype in each mother-baby pair, exhibiting important inter-individual variability. The present analysis does not support the contention that this source of variability accounts for the variability in the duration of lactational amenorrhoea.     

Analysis of postpartum lactational amenorrhoea in relation to breast-feeding: some methodological and practical aspects.

A large multicentre epidemiological study was carried out by WHO between 1991 and 1995 to analyse the duration of lactational amenorrhoea in relation to breast-feeding. The main results of this analysis, which used classical statistical modelling, have been already published. However, some specific aspects of the postpartum fertility amenorrhoea and breast-feeding covariates, and more specifically the observed progressive exhaustion of the breast-feeding inhibitory effect on the reproductive axis, may justify a closer look at the validity of the statistical tools. Indeed, as has already been emphasized, analysis of large longitudinal data sets in reproduction often faces three difficulties: (i) the precise determination of the event of interest, (ii) the way to handle the time evolution of both the studied variables and their effect on the event of interest and (iii) the often discrete nature of the data and the associated problem of tied events. The first objective of the present work was to give additional insights into the estimation and quantification of the dynamics of the effect of breast-feeding over time, considering this covariate either as fixed or time-dependent. The second objective was to show how to perform the analyses using corresponding adapted procedures in widely available statistical packages, without the need for acquiring particular programming skills.     

Nursing behaviour and its relation to duration of post-partum amenorrhoea in an Andean community

Nu?oa is a high altitude rural Peruvian community characterized by socioeconomic stratification and differential access to the market economy. Nursing practices and the effects of nursing are also stratified; this translates into a risk of menses at 12 months post-partum nearly seven times greater in wealthier than in poorer women. Most nursing occurs in the morning, among those who practice on-demand breast-feeding. Nursing episodes are clustered into sessions; the amount of breast-feeding is regulated by varying the number of episodes per session rather than by changing the duration of suckling episodes or the frequency of sessions per hour. Thus, resumption of ovulation is not dependent on the variable spacing of nursing episodes or sessions. The components of nursing activity most likely to be responsible for variation in the duration of post-partum amenorrhoea in these nursing women are mean session duration and mean number of episodes per session. The mean duration of morning nursing sessions is negatively associated with infant's age, reflecting the greater reliance of younger children on breast-milk. The mean duration of afternoon nursing sessions is positively associated with mother's age, independent of infant's age, possibly reflecting maternal age-related variation in milk production capabilities. Baby minding by older daughters may also help to explain variation in afternoon nursing.     

Effectiveness of lactational amenorrhoea in prevention of pregnancy in Manila,the Philippines: non-comparative prospective trail.

OBJECTIVE: To determine the contraceptive efficacy of the lactational amenorrhoea method. DESIGN: Non-comparative prospective trial. SETTING: Urban Manila, the Philippines. SUBJECTS: 485 lower income, educated women with extensive experience of breast feeding. INTERVENTION: Women were offered all available contraceptives for use after birth. Those who chose the lactational amenorrhoea method were taught the method, screened for the study, and followed for 12 months to determine the risk of pregnancy when the method was used. MAIN OUTCOME MEASURES: Life table pregnancy rates during correct and incorrect use of the method, censored monthly in the event of sexual abstinence or the use of another contraceptive method. RESULTS: The lactational amenorrhoea method was 99% effective when used correctly (that is, during lactational amenorrhoea and full or nearly full breast feeding for up to six months). At 12 months the effectiveness during amenorrhoea dropped to 97%. CONCLUSIONS: The lactational amenorrhoea method provided as much protection from pregnancy as non-breast feeding women experience with non-medicated intrauterine devices and barrier methods. The contraceptive effect of lactation cannot be attributed to lactational or postpartum abstinence.     

Aggregation of spores and its effect on aerodynamic behaviour

Spores of fungi and actinomycetes are often aggregated, greatly affecting their aerodynamic behaviour with significance for both plant pathology and medicine. However, apart from experimental work with inorganic particles relative to industrial hygiene and lung deposition, the effects of aggregation on aerodynamic behaviour have been little studied. The available information is reviewed and methods are suggested for the study of microbial aggregates.     

Direct effect of bombesin on pancreatic and gastric growth in suckling rats.

Bombesin stimulates growth of the stomach and pancreas in adult rats. Part of this effect is thought to be through the release of CCK following bombesin treatment. We studied the effect of long term administration of bombesin on the pancreas and stomach in suckling rats and examined the action of bombesin using specific CCK antagonist (CR-1409) and bombesin antagonists (GRP19-26, D-Phe19, Leu26CH2NHCOCH3 = cpd 17; L-686,095-001C002 = cpd 23). Rat pups (7-days-old) were given bombesin (20 micrograms/kg body wt. twice a day) or vehicle (1% gelatin) for 9 days. Bombesin stimulated pancreatic and gastric growth (tissue weight, total protein and DNA content all increased). Pancreatic trypsinogen concentration and content showed a 2-3-fold increase. CR-1409 at 6 mg/kg body wt., a dose that blocked the trophic action of CCK-33 when given to pups at similar ages, did not affect the bombesin-stimulated growth of the pancreas or the increase in trypsinogen level. At 2.4 mg/kg body wt., cpd 17 partially blocked and cpd 23 completely blocked the trophic effect of bombesin on the pancreas and stomach and the increase in trypsinogen level in the pancreas. RU-486, a type II glucocorticoid receptor antagonist, given at a dose sufficient to block the physiological action of glucocorticoid, had no effect on bombesin-stimulated growth of the pancreas. Thus, in vivo, bombesin acts directly on the neonatal pancreas and stomach.     

Effect of age of calf on suckling behaviour and other behavioural activities of Zebu and crossbred calves during restricted suckling periods

The objective of this study was to investigate the effect of age of calf on the behaviour of Zebu and crossbred calves during restricted suckling (RS) periods. The behaviours of 20 Zebu and 16 crossbred calves were recorded during two 30-min sessions each day after milking when the calves and their dams were brought together in a group for suckling. This was made for a time period of 2 weeks/month for 6 months postpartum.The total suckling duration was significantly longer in Zebu calves (11.8+/-0.19 min) compared to the crossbred calves (9.4+/-0.19 min), but decreased significantly in both breeds with increasing age from 1 to 6 months. The number of suckling bouts decreased from a mean of 3.8 at 1 month of age to 1.1 at 6 month (P<0.05). The duration of each suckling bout decreased significantly from a mean of 3.5+/-0.15 min at 1 month of age to 1.6+/-0.01 min at 6 months (<0.05). The frequency of crossbred calves cross-suckling (3.7%) was significantly higher than that of the Zebu calves (1.9%; P<0.05). The frequency of calves cross-suckling decreased significantly from 4.2% at 1 month of age to 2.3% at 6 months. The duration and number of bouts of cross-suckling was significantly higher in the crossbred calves (duration 0.9+/-0.06 min; bouts 3, 7) than in the Zebu calves (duration 0.5+/-0.06 min; bouts 2, 7) and decreased with increasing age of calf. The duration and number of bouts of inter-sucking was significantly higher in the crossbred calves (duration 0.6+/-0.07 min; bouts 1, 6) than in the Zebu calves (duration 0.1+/-0.04 min; bouts 0, 5) and decreased with increasing age of calf. Exploration increased in duration as the calves increased in age from 1 to 6 months (P<0.05). The duration of play increased significantly with the increase in age of calf from 1 to 6 months, and occurred mainly after nursing.     

Electrically recorded feeding behaviour of cassava mealybug on host and non-host plants

The feeding behaviour of cassava mealybug (Phenacoccus manihoti) was analysed by the electrical penetration graph technique (EPG, DC-system) and by light microscopy. This study confirmed a typical phloem-feeding behaviour with an aphid-like predominance of extracellular pathways of stylets. Similarities of EPGs from mealybugs with those of aphids and whiteflies allowed adoption of standard pattern labelling. The main differences with aphid EPGs consisted of fewer but longer intracellular punctures (pd duration of 20 svs 5–7 s for aphids), longer times to the first phloem-ingestion period and a lower motility of stylets within the phloem searching process. Comparison of the feeding behaviour on 6 plant types, including two occasional hosts (Talinum and poinsettia), one cassava hybrid and three common cassava cultivars (Manihot esculenta), allowed differentiation of penetration profiles. Intracellular punctures were shorter on occasional hosts, on which phloem finding and subsequent ingestion were markedly delayed although a great variability within plants persisted. Chemical analysis of some secondary plant substances revealed that none of the plants tested contained detectable amounts of alkaloids, and that cyanides were restricted to true hosts (cassavas andManihot hybrid). Levels of total flavonoids did not differ between hosts and non-hosts, in contrast to those of phenolic acids. Preliminary correlations with EPG paterns are discussed.

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Résumé Le comportement alimentaire de la cochenille du manioc (Phenacoccus manihoti) a été étudié par électrographie de pénétration (EPG, analyse en courant continu) et par microscopie optique. Cette étude a permis de confirmer le caractère typiquement phloémophage de l'alimentation de cet Homoptère, présentant une large prédominance du trajet extracellulaire des stylets, comme cela est également observé chez les pucerons. Les similitudes des tracés EPG effectués sur cochenille et sur pucerons ou aleurodes ont permis d'adopter la même typologie du signal. Les principales différences avec les pucerons concernent le nombre moins important et la durée plus longue des ponctions intracellulaires (20 s en moyenne contre 5 à 7 s chez les pucerons), l'allongement du temps d'accès au phloème et une moins grande mobilité des stylets lors de la phase de recherche du phloème. La comparaison du comportement alimentaire sur 6 plantes, parmi lesquelles deux h?tes occasionnels (Talinum et poinsettia), un hybride et trois variétés courantes de manioc (Manihot esculenta), a permis de différencier plusieurs profils de pénétration. Les ponctions intracellulaires se sont révélées plus courtes sur h?tes occasionnels, qui induisent également, malgré la variabilité observée, un allongement net de la période de localisation du phloème et donc un retard à l'ingestion. Aucune des plantes testées ne contient d'alcalo?des, et les composés cyanés se restreignent au genreManihot, h?te naturel de la cochenille. Les flavono?des totaux ne permettent pas de distinguer plantes h?tes et non-h?tes, à la différence des acides phénoliques.

     

Resumption of oestrous behaviour and cyclic ovarian activity in suckling and non-suckling ewes

In Préalpes de Sud ewes after an autumn lambing, the mean post-partum interval to first LH surge was 10 +/- 1 days and 17 +/- 1 days for non-suckling and suckling ewes, respectively. Post-partum interval to first luteal phase, estimated from plasma progesterone concentrations, was similar in non-suckling and suckling ewes (27 +/- 1 days and 28 +/- 5 days, respectively). Interval to first oestrus was shorter in non-suckling (22 +/- 2 days) than in suckling ewes (35 +/- 2 days) but these first oestrous periods were followed by short luteal phases in 60% (12/20) of non-suckling ewes and in only 7% (2/29) of suckling ewes. Finally, suckling slightly postponed the resumption of the first oestrus followed by a normal oestrous cycle (37 +/- 1 days versus 31 +/- 2 days) because progesterone, essential for oestrus expression, was secreted mainly during normal luteal phases in 70% (21/30) of suckling ewes and during short cycles in 95% (21/22) of non-suckling ewes. Therefore, the primary consequence of suckling is to regulate the conditions of resumption of cyclic ovarian activity after parturition.