Ovum recovery and in vitro fertilization in crab-eating monkeys (Macaca fascicularis)

A total of 301 oocytes were recovered from crab-eating monkeys and subjected to insemination in vitro resulting in two fertilized ova. Sixteen monkeys in 24 cycles received 37.5 IU of hMG daily from the second day of the menstrual cycle for 7 to 10 days. Oocytes were recovered under laparotomy at 20 to 49 hr after administration of 1,000–1,500 IU of hCG. The maturation rate of the recovered oocytes was 24.2% as judged from morphological criteria under the light microscope. With additional maturation culture, the rate increased to 36.2%. The matured oocytes were inseminated at 3 to 4 hr after aspiration using homologous spermatozoa which had been capacitated in vitro. Two oocytes were judged as being fertilized based on the presence of 3 and 5 pronuclei, respectively, when examined 12 hr after the insemination. This is the first report of in vitro fertilized ova in nonhuman primates in Japan.     

Age-dependent changes in fecal 17β-estradiol and progesterone concentrations in female spider monkeys (Ateles geoffroyi)

The objective of this study was to investigate whether sex steroids decreased with age in female black-handed spider monkeys (Ateles geoffroyi). Fecal concentrations of 17β-estradiol and progesterone (five samples/wk) and the number of ovulatory and anovulatory cycles were compared between adult (n = 3) and aged females (n = 2). All animals (regardless of age) had higher 17β-estradiol concentrations during the fertile than the nonfertile phases. However, during the fertile phase, concentrations of this hormone were significantly higher in adult females. Conversely, progesterone concentrations varied normally throughout the menstrual cycle in both adult and aged animals, with no significant difference between age classes. Similarly, there was no significant effect of age on the number of ovulatory and anovulatory cycles. In conclusion, we inferred that the aged female spider monkeys did not reach menopause, instead they remained in a perimenopausal period characterized by changes in fecal concentrations of ovarian steroids and hypothalamus-hypophysis-ovary axis activity, as well as irregular menstrual flows, for prolonged intervals.     

Cyclic changes in the charge profile of LH in anterior pituitary glands of adult female Japanese monkeys (Macaca fuscata).

Thirteen adult female Japanese monkeys (Macaca fuscata) were sacrificed in the early and the late follicular phase, and in the mid-luteal phase of the menstrual cycle, and also after castration. Pituitary LH content correlated significantly with plasma estradiol levels but not progesterone levels in the cycling monkeys. Pituitary LH species were fractionated by isoelectrofocusing (1EF). Pituitary LH species were separated into six fractions by IEF. High alkaline LH and alkaline LH were the most abundant species in the late follicular phase and the mid-luteal phase, respectively. Neutral LH and acidic LH were the most abundant in the early follicular phase and in the castrates. Pituitary LH thus changed qualitatively and quantitatively during the menstrual cycle and after castration.     

Monitoring the reproductive status of Japanese monkeys (Macaca fuscata) by measurement of the steroid hormones in fecal samples

The menstrual cycles as well as the pregnancy in female Japanese monkeys (Macaca fuscata) were monitored by measuring the fecal estradiol concentrations and relative amounts of fecal progesterone. Steroids from fecal samples were extracted by using a previously developed simplified two-step method and then measured by radioimmunoassay. We successfully demonstrated that the two-step method is effective and convenient for monitoring the reproductive status of Japanese monkeys.     

Growth and reproductive parameters of bonnet monkey (Macaca radiata)

The present paper summarizes some of the important biological and physiological data recorded over a 30-year period on the biology of bonnet monkeys in captivity. Data on sexual maturity, menstrual cyclicity, general behaviour, endocrine profile, reproductive physiology, gestation, parturition, postpartum amenorrhoea in the female, and sexual maturity, hormone profile, and seasonal variation in sperm count of the male monkeys are presented. In addition to the biological values, weights of selected organs, vertebral and dental pattern are also presented. Menarche occurred at an age of 36±4 months and the first conception in the colony occurred at an age of 54±4 months. The average menstrual cycle length was 28±4.3 days. Majority of monkeys did not cycle regularly during March–June during which the temperature reached a peak. The pregnancy index of the colony was 80% with controlled breeding. The gestation period was 166±5 days with 6–7 months postpartum amenorrhoea. Males attained sexual maturity by the age of 6–7 years and exhibited the characteristic nocturnal surge of serum testosterone at this age and sperm concentration ranged from 116–799 millions/ejaculate.     

Luteolytic action of 15-keto prostaglandin F2α in the rhesus monkey

The naturally-occurring metabolite of prostaglandin F_2α, 15-keto prostaglandin F_2α (15-keto PGF_2α), elicited rapid and sustained declines in serum progesterone concentrations when administered to rhesus monkeys beginning on day 22 of normal menstrual cycles. Evidence for luteolysis of a more convincing nature was obtained in studies where a single dose of 15-keto PGF_2α was given on day 20 of ovulatory menstrual cycles in which intramuscular injections of hCG were also given on days 18–20; serum progesterone concentrations fell precipitously in monkeys within 24 hours following intramuscular administration of 15-keto PGF_2α. However, corpus luteum function was impaired in only 4 of 11 early pregnant monkeys when 15-keto PGF_2α was administered on days 30 and 31 from the last menses, a time when the ovary is essential for the maintenance of pregnancy. Gestation failed in 2 additional monkeys 32 and 60 days after treatment with 15-keto PGF_2α, but progressed in an apparently normal manner in the remaining 5 animals. Two pregnant monkeys treated with 15-keto PGF_2α on day 42 from the last menstrual period, a time when the ovary is no longer required for gestation, continued their pregnancies uneventfully. Corpus luteum function was not impaired in 9 control monkeys which received injections of vehicle or hCG at appropriate times during the menstrual cycle or pregnancy.     

Comparative effects of interferon alpha‐2b and pegylated interferon alpha‐2b on menstrual cycles and ovarian hormones in cynomolgus monkeys

BACKGROUND : The covalent modification of interferon (IFN) α2b with monomethyoxy polyethylene glycol (PEG) reduces its clearance rate and increases its half‐life. High doses of interferon (IFN) α2b have previously been shown to affect maintenance of pregnancy in rhesus monkeys. Given the role of ovarian hormones in reproductive function and pregnancy, this study was conducted to assess the effects of PEG‐IFNα2b or IFNα2b (comparative control) on ovarian hormones and menstrual cyclicity in cynomolgus monkeys. In addition, the potential for reversibility of PEG‐IFNα2b or IFNα2b‐related observations was assessed. METHODS : Monkeys were administered 3,105 µg/m² human recombinant (hr) IFNα2b or 52, 262, or 4,239 µg/m² PEG‐hr‐IFNα2b every other day for one menstrual cycle, followed by a post‐dose period of up to two menstrual cycles. RESULTS : Monkeys administered 3,105 µg/m² hr‐IFNα2b or 52, 262, or 4,239 µg/m² PEG‐hr‐IFNα2b exhibited transient decreases in food consumption, leukocyte and erythrocyte parameters. Monkeys administered 3,105 µg/m² hr‐IFNα2b exhibited lengthened menstrual cycles that were associated with a delay in reaching peak ovarian hormone levels and lower respective peak concentrations. Similarly, monkeys administered 4,239 µg/m² PEG‐hr‐IFNα2b exhibited lengthened menstrual cycles and a delay in reaching peak ovarian hormone levels and slightly lower respective peak concentrations. Post‐dosing menstrual cycle length, estradiol and progesterone profiles exhibited evidence of recovery in both the hr‐IFNα2b and the high‐dose PEG‐hr‐IFNα2b groups. CONCLUSIONS : Administration of hr‐IFNα2b or PEG‐hr‐IFNα2b at high doses to cynomolgus monkeys resulted in similar effects on menstrual cycles, estradiol and progesterone profiles, and exhibited evidence of reversibility upon cessation of dosing. These results suggest that the previously observed high‐dose IFNα‐related effects on the maintenance of pregnancy in monkeys are likely the result of altered ovarian function. Birth Defects Res (Part B) 86:29‐39, 2009. © 2009 Wiley‐Liss, Inc.     

The extensor and peroneal muscles of the crab-eating monkey (Macaca fascicularis)

On the basis of 60 hindlimbs of 30 crab-eating monkeys (Macaca fascicularis) of each sex, the morphology of the crural extensor and the peroneal group of leg muscles is described and some functional indices are calculated. For the attachments and measurements of the muscles, the results obtained in this study generally agreed with those of otherMacaca species. The crural extensor has minor differences. Some anomalous modes of insertion are observed in the peroneal group. These results indicate the phyletically labile state of the peronei in the crab-eating monkey.     

Historic mussel beds (Mytilus edulis) in the sedimentary record of a back-barrier tidal flat near Spiekeroog Island, southern North Sea

Mussel beds show irregular cycles of appearance, disappearance and reappearance at preferred distinct locations on intertidal flats. These cycles are documented in the depth profile by the presence of shell-rich sediments intercalated with sandy layers. Such mussel bed layers were regularly found over the past 12 years on the Swinnplate, a back-barrier tidal flat south of Spiekeroog Island, southern North Sea. They are characterised by the occurrence of sub-articulated pairs of Mytilus shells. Based on life span considerations, a period of at least 35–40 years over which mussel beds may have repeatedly established themselves is suggested. A survey in spring 2000 revealed a reduced occurrence of old, embedded beds on the Swinnplate. The present results, based on core profiles from 1992 to 2000 and amino acid age determination, show that alternations of shell layers indicative of former Mytilus beds and sediment layers provide insight into the historic development of tidal flat environments. The frequent occurrence of sub-articulated valve pairs in the shell layers documents that the embedding of the mussel beds took place soon after the death of the organisms without prior physical disturbance. Successions of historic Mytilus beds provide evidence that mussel beds are a regular, but not necessarily permanent, faunal feature of back-barrier tidal flats of the North Sea. Electronic Publication     

Synchrony of estrous swelling in captive group-living chimpanzees (Pan troglodytes)

Recent findings suggest that menstrual synchrony may occur in humans and is more dependent on factors of close personal association than simple prox imity. Part I of this study analyzed the estrous cycles of 10 captive group living chimpanzees (Pan troglodytes) housed in two separate groups in the same building. Each group contained at least one male. The mean discrepan cies for (1) the approximate day of ovulation (last day of maximum swelling) and (2) the day of onset of estrous swelling were determined for all possible pairs within groups and compared to the mean discrepancies of pairs between groups. With respect to the probable day of ovulation, the mean discrepancy of animals caged together was 8.0 days and that of animals caged separately was 10. 7 days. Comparing the onset of estrous swelling, the mean between groups was 10.4 days, whereas females caged together averaged only 5.7 days. A repeated-measures analysis of variance indicated a significant group effect in the onset of estrous swelling (F = 5.68,p < 0.05), whereas there was no significant difference between the animals caged together and those caged separately with respect to the last day of maximum swelling (F = 1.37, NS). Part II of the study compared the onset of the first postpar tum estrus (PPE) to the onset of estrus in cagemates. During a 6-year period, 13 females exhibited 33 PPEs while in social contact with cycling females. Of 86 paired comparisons, the PPE onset of 43 (50%) occurred with in 6 days of the swelling onset of a cagemate. The results suggest that, as in other species (including humans), the social contact and time spent together influence the synchrony of chimpanzee estrous cycles, especially in terms of swelling onset. The synchrony of estrous swelling and possible mediation by olfactory and/or hormonal cues are discussed as they relate to chimpanzee social structure and female reproductive strategy.     

Menstrual cycle and some other related aspects of Japanese monkeys (Macaca fuscata)

The menstrual cycle and some other related aspects of Japanese monkeys (Macaca fuscata) were dealt with in this paper. Almost all the monkeys had regular menstrual cycles only in the mating season, and had no menstrual cycles, or only irregular ones, in the non-mating season. The average length of the menstrual cycle in the mating season was 26.3 ±5.4 days. Many monkeys had a tendency to have their own individual and relatively regular cycles. Ninety out of 108 monkeys kept in the air-conditioned quarters for five years showed “periodical changes” essentially coincident with the changes of outdoor season, and this fact suggests that the rhythm of the seasonal change of Japanese monkeys remains for a relatively long period even if the monkeys are kept in air-conditioned quarters where room temperature and lighting are kept constant throughout the year. Vaginal smear, cervical mucus, sexual skin, etc. were observed in relation to ovulation. These characters showed cyclic changes with menstrual cycles in about half of all cases observed, but ovulation occurred even in the cases in which no cyclic change was observed. Therefore, it was not necessarily easy to estimate the ovulation by observing these characters.     

Behavioral changes across the menstrual cycle in isosexual groups of bonnet macaques (Macaca radiata)

Behavioral changes were systematically recorded across menstrual cycles over a six-month period in two laboratory-housed isosexual triads ofMacaca radiata (bonnet macaque). The purpose of this study was to determine whether females of this species demonstrate premenstrual behavioral changes as reported for humans, or heightened levels of aggression during the first half of their cycle as reported in some species of Old World monkeys. A total of 34 menstrual cycles were divided into five segments including two follicular, one periovulatory, and two luteal phases. The mean frequencies of behaviors were analyzed according to phase, rank, and time since triad formation, for a total of 34 menstrual cycles. There was no evidence of an increase in spatial separation during the premenstrual phase or during any other phase of the menstrual cycle. Although contact aggression did not show an increase during the early follicular half of the cycle (phases 1 and 2) or during the phase of the cycle immediately preceding menses (phase 5), contact aggression did show two peaks: one in the early-mid luteal half of the cycle (phase 4) and a peak in the mid-late follicular (phase 2). The non-aggressive hierarchical behaviors did not follow the same pattern as contact aggression. Instead the distribution of these behaviors showed a pattern similar to that of estrogen levels across the cycle. Subjects’ location in pen also varied significantly according to cycle phase: subjects spent more time on perches during the premenstrual phase and more time on the pen floor during the periovulatory phase. The increase in contact aggressive behaviors during the early-mid follicular phase and the mid-late luteal phase does not suggest a simple hormonal correlate as these two phases are characterized by high levels of estrogen and progesterone, respectively. However, the distribution of non-aggressive hierarchical behaviors suggest that this category of agonistic interaction may be related to mating competition among females of this species. Results are discussed with reference to the social behavior and promiscuous mating strategy ofM. radiata. The findings in this present study are compared with previous studies utilizing other species of Old World monkeys. Differences in study design and group composition are considered as factors effecting discrepant results both within and between species.     

Morphology of diaphragm in the crab-eating monkey (Macaca fascicularis)

The diaphragm was studied in 30 adult crab-eating monkeys (Macaca fascicularis). The muscular bundle of the lumber part was derived from the tendinous origin, which attached to the anterior surface of the lumbar vertebra and intervertebral disc. The upper margin of the origin was at the one third of the second lumbar vertebra in both sides. The lower margin of the right and left tendons extend to lower one third and upper one third of the third lumbar vertebra, respectively. In 22 cases (73.3%) out of 30 specimens, some muscular bundles arose from the right crus with the collagenous sheath. They ran across the ventral aspect of the aortic hiatus and bounded the esophageal hiatus at the left side. The muscular fibers, which bound the esophageal hiatus at the right and left, are innervated by ipsilateral phrenic nerve. In four cases, the “Hilfsmuskel” after Treitz was observed. It arose from the connective tissue around the coeliac artery.     

A description of the upper thoracic autonomic nervous system in the rhesus monkey (Macaca mulatta)

The purpose of this study was to describe the autonomic innervation of the carotid sinus and heart in the rhesus monkey. Nine male rhesus monkeys (Macaca mulatta) and one male crab-eating macaque (M. fascicularis) were carefully dissected from the origin of the vagus nerves and superior cervical ganglia to the level of the fourth thoracic ganglion. The specimens were either freshly killed or obtained no later than 24 hours post mortem. The macaque monkeys were found to possess an innervation pattern that displayed features common to dog (connections between the vagus nerves and middle cervical ganglia), baboon (distinct cervical sympathetic and cervical vagal nerve trunks), and man (nerves projecting from the middle cervical and stellate ganglia to the heart). Distinct inferior cervical and first thoracic ganglia were never seen, but rather, large and well defined stellate ganglia were found. The macaque innervation pattern, when considered as a whole, most closely resembled the baboon.     

Reproductive biology of Sykes and blue monkeys (Cercopithecus mitis)

Thirty-five live births were recorded over a 5-year period from three subspecies of the mitis (Sykes and blue) monkey (Cercopithecus mitis) maintained outdoors in single-male harem breeding groups. There was no indication of birth seasonality. Females of one subspecies, C. m. kolbi, were individually caged, and basic reproductive parameters were monitored. A menstrual cycle length of 31.9 ± 6.0 days was recorded, and there were a large number of irregular cycles. Within individuals, mean progesterone and estrogen concentrations during the luteal phase of the cycle ranged from 5.5 to 10.7 nmol/liter and from 542 to 829 pmol/liter, respectively. Attempts at timed matings were unsuccessful. It is concluded that the mitis monkey is slow to adapt reproductively to captivity and is, therefore, not especially well-suited for routine reproductive studies. However, it may prove valuable to elucidate some of the more complex factors controlling guenon reproduction.     

Atretogenic action of estrogen in rhesus monkeys: Effects of repeated treatment

The effects of 17β-estradiol (E₂), administered in Silastic capsules for 24 hours at intervals of 10 or 14 days, on follicular development and menstrual cycle characteristics were studied in 13 rhesus monkeys. In seven monkeys receiving E₂ at l0-day intervals for 50 treatment periods, new follicles frequently developed between treatments but usually regressed. In seven instances, the follicles persisted longer than expected but were steroidogenically suppressed and regressed spontaneously. Ovulation occurred in only two instances. In six monkeys receiving E₂ at 14-day intervals, new follicles developed regularly, with seven ovulations occurring in 37 treatment periods. A persistent anovulatory follicle was noted in only one instance. Menstruation occurred with equal frequency, and the interval from treatment to onset of menstruation was not significantly different regardless of treatment or the occurrence of ovulation; the intervals between menstruation approximated those of normal menstrual cycles. In general, following termination of treatment, menstrual cycles returned to normal quickly. These data indicate that E₂ administered intermittently at 10-day intervals effectively suppresses ovulation, and they provide new insight into the actions of E₂ on folliculogenesis in primates.     

Some characteristics of the normal menstrual cycle of the bonnet monkey (M. radiata)

Sixty-two menstrual cycles were observed in five bonnet monkeys over a period of 12 months. The menstrual cycles ranged in length from 22 to 35 days, although cycles of from 26 to 29 days were most frequent. Menstrual flow occurred for two to seven days, the flow lasting for three to four days in the majority (82%) of the cycles. Serum estradiol-17β (E₂) and progesterone (P) were measured by radioimmunoassay in two consecutive cycles in each monkey and correlated with changes in the quantity of cervical mucus secretion and spinnbarkeit. The day of the estradiol peak was considered as day 0. The E₂ levels began to rise one to three days before the peak, returning to baseline levels within two days and thereafter remained at low levels. The serum P rose 2 days after the E₂ peak, and maximum level was attained at 10 to 12 days after the E₂ peak. The quantity of cervical mucus increased proportionately with estrogen. However, the quantity remained at maximum levels even after the decline of the serum E₂ level. Similar trends were observed with the spinnbarkeit.     

The menstrual cycle of the spider monkey (Ateles geoffroyi)

The ovarian cycles of four adult female spider monkeys (Ateles geoffroyi) were followed daily throughout 30 days by means of vaginal swabs and blood samplings. Cytological analyses of the vaginal swabs and radioimmunoassay determination of the daily levels of estradiol-17β (E₂) and progesterone (P₄) were done in order to classify the kind of ovarian cycle of this species. Our results show that Ateles geoffroyi females display menstrual cycles of about 24 days on average. By comparison with the well-known menstrual cycles of women, apes, and Old World monkeys, the four distinctive cytological phases (bleeding, follicular, periovulatory, and luteal) could be recognized; mid-cycle E₂ peaks followed by mid-luteal increases of the same hormone were present in all four females. P₄ levels were higher after the E₂ peak, although both hormones were present throughout the cycles. Also, age-dependent features, hormone profiles, and changes in menstrual phases lengths were detected. Am. J. Primatol. 44:183–195, 1998. © 1998 Wiley-Liss, Inc.     

The influence of snowfall,temperature and social relationships on sleeping clusters of Japanese monkeys during winter in Shiga Heights

We studied Japanese monkeys (Macaca fuscata) of the Shiga A₁ troop at their sleeping sites in Shiga Heights, Japan, for 41 nights during 3 winters. Monkeys chose their sleeping sites in Japanese cedars and in deciduous broad-leaved forests on non-snowing nights and in Japanese cedar forests on snowing nights. We counted 399 sleeping clusters in which 2 or more monkeys remained in physical contact through the night and 43 solitary sleeping monkeys, though monkeys did not maintain physical contact with others in the daytime. We found 397 clusters on tree branches and 2 clusters on rocks. The mean size of huddling clusters was 3.06±1.22 SD. The cluster size (3.17±1.26 SD) at lower ambient temperatures between −7 and −4°C was larger than that at higher temperatures between −2 and 4°C (cluster size 2.88±1.13 SD). Most clusters were composed of kin. Females kept close to related females in the daytime and huddled with them at night. The highest-ranking male mainly huddled with his kin and his familiar females. Other males kept farther apart from each other in the daytime, probably to avoid social conflicts. Through cold winter nights, however, such males reduced inter-individual distances and huddled with other males. Japanese monkeys appear to recognize three types of inter-individual distances: an intimate distance less than 1 m, a personal distance of 1–3 m and a social distance of 3–20 m; they change their inter-individual distances according to social and ecological circumstances.