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Biomedical subjects

K Westlund

Publications and source records attributed to K Westlund.

At least 19 recordsLinked to original sources
PubMed2000

Post-conflict affiliation in common marmosets (Callithrix jacchus jacchus).

Post-conflict (PC) affiliation has been demonstrated in a number of Old World monkeys and apes, but very little is known about the occurrence of the phenomenon in New World monkeys. This study examined 282 PC interactions after spontaneous conflicts around feeding time in two family groups (N = 12) of captive common marmosets, Callithrix jacchus jacchus. We found an overall corrected conciliatory tendency of 31%. Selective attraction was seen: former opponents met significantly more often in PCs than in matched controls (MCs) (27% and 16%, respectively). There was no difference in the occurrence of PC affiliation between dyads consisting of parent-offspring constellations compared to offspring-offspring constellations. PC affiliative behaviors were seen in the first three minutes following conflict termination, and consisted mainly of proximity, play invitations, and food transfer. Notably, former opponents remained within arm's reach after 17% of conflicts. Affiliation was more likely to follow after conflicts involving play issues. The functional importance of the PC affiliation in marmosets remains to be examined.

Aggression↗
PubMed1999

Conflict resolution in 5-year-old boys: does postconflict affiliative behaviour have a reconciliatory role?

In nonhuman primates, affiliative behaviours, such as social grooming and various forms of body contact, become more frequent after an aggressive interaction. Since such behaviours lead to a decrease in postconflict aggressive behaviour and displacement activities and to increased social tolerance, they have been labelled reconciliatory. We videofilmed sessions of free play in daycare centres in Stockholm and investigated whether affiliative behaviours used by 5-year-old boys in the postconflict period had a similar reconciliatory function. For 219 conflicts in 21 h 40 min of observation we recorded postconflict affiliative/prosocial, aggressive and displacement behaviours. When affiliative behaviours were shown and accepted by the opponent, aggressive and displacement behaviours decreased and play was promoted. These behaviours thus serve a function similar to reconciliatory behaviour in nonhuman primates and we think it is applicable to call accepted affiliative behaviours in postconflict periods of preschool children reconciliatory. However, conflicts were often polyadic and nonconflict periods consisted of intense play with a rich exchange of affiliative behaviours. These factors were limitations to the postconflict/matched-control method traditionally used in primatological research to document reconciliatory behaviour. We suggest that for preschool children, video recordings and an analysis and description of postconflict affiliative, aggressive and displacement behaviours can be used instead. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1982

Age at menarche, urine estrogens and breast cancer risk.

In 511 nulliparous women aged 15-19 years and 347 aged 30-39, an analysis has been undertaken of the relationship of urine concentrations of the three principal estrogens to age, age at menarche and Quetelet's index of adiposity. The analysis was undertaken by means of multiple regression, controlling for each of the 12 centers from which the data originated, as well as for the other study variables. In the younger women, age was strongly and positively related to concentrations of E1 and E2 and less so to E3. In the age group 30-39, follicular phase specimens showed positive relationships with age for all three fractions but luteal specimens did not. Age at menarche showed inverse relationships to levels of E1 and E2 which were significant in the younger but not in the older age group. The associations of estrogens with Quetelet's index were weak and not statistically significant. The data suggest that women whose menarche occurs early not only have a longer duration of exposure to estrogens during years which are probably important in the initiation of breast cancer but, in addition, their exposures are at a higher level during those years and probably at later ages also. These observations support the hypothesis that the mechanism of the association of early menarche with breast cancer risk is via the association of both with estrogen stimulus.

Adipose Tissue↗
PubMed1982

Age at menarche, probability of ovulation and breast cancer risk.

An analysis is undertaken of the frequency of ovulation in 17 groups of women aged 15 to 19 who had been the subjects of other studies. A urine specimen of at least 8 h accumulation had been provided on the 20th or 21st day of a menstrual cycle by 681 women. Analysis is restricted to 431 specimens which had been collected between 11 and 3 days prior to the onset of the subsequent menstrual period. A pregnanediol concentration of less than 1 mg per litre in such a specimen was taken as evidence that the cycle was anovular. The probability of a cycle being anovular was inversely and significantly related to the number of years since menarche, and, with years since menarche held constant, was positively but not significantly associated with age at menarche. This observation indicates that women with early menarche do not have a longer duration of exposure to anovular cycles than do those whose menarche is delayed, and that variation in the duration of exposure to post-menarcheal anovular cycles does not explain the association of breast cancer risk with early age at menarche. The 17 groups of women were classified into four categories according to ethnic origin and breast cancer incidence in the populations from which they derived. Anovular cycles were not more common in the high-risk groups; indeed, the two centers in the lowest risk category had the highest proportion of anovular cycles.

Adolescent↗