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Biomedical subjects

K H Tennekoon

Publications and source records attributed to K H Tennekoon.

18 recordsLinked to original sources
PubMed2001

Lactational amenorrhea/anovulation and some of their determinants: a comparison of well-nourished and undernourished women.

OBJECTIVE: To study the effect of maternal nutritional status and some other possible determinants on lactational amenorrhea/anovulation. DESIGN: Prospective matched-pairs study. SETTING: Postpartum wards and community and academic settings. PATIENT(S): Thirty matched pairs of otherwise healthy, well-nourished (body mass index > or = 26.00 kg/m2) and undernourished (body mass index < or = 19.00 kg/m2) postpartum women were selected. INTERVENTION(S): Infant feeding pattern was recorded weekly, and infant weights, maternal body mass index, and maternal PRL levels were estimated every 4 weeks until resumption of menstruation. Ovulatory activity was determined using urinary estrone and pregnanediol glucuronide concentrations. MAIN OUTCOME MEASURE(S): Time of resumption of menstruation, regular and ovulatory. RESULT(S): Well-nourished women resumed regular menstruation significantly earlier than undernourished women but resumed ovulatory menstruation at almost the same time. Undernourished women had fewer anovulatory cycles preceding first postpartum ovulation and a higher prevalence of formula feeding. Effect of body mass index on lactational amenorrhea became nonsignificant when nonintroduction of formula feeds, maternal age, and socioeconomic status were controlled for. CONCLUSION(S): Improved maternal nutritional status has no significant effect on fertility: ovulation is not advanced despite early resumption of regular menstruation.

Adult↗
PubMed2001

Maternal prolactin concentrations and lactational behaviour in the early postpartum period in women with lactational amenorrhoea.

OBJECTIVE: To compare early postpartum differences in maternal prolactin concentrations and lactational behaviour between women who have short and long periods of lactational amenorrhoea. METHODS: Healthy lactating women resuming regular menstruation before 24 weeks [short amenorrhoea (SA) group; n = 15], and at or after 24 weeks [long amenorrhoea (LA) group; n = 15] postpartum were studied from 4 to 12 weeks postpartum. Infant feeding pattern and maternal plasma prolactin concentrations were compared between the two groups using repeated measures ANOVA. RESULTS: Breastfeeds/24 h were significantly higher and other feeds/24 h were significantly lower (p < 0.01) at 12 weeks postpartum in the LA group when expressed as a percentage of all feeds. Number of breastfeeds (total/24 h and night) significantly decreased and the number of other feeds significantly increased (p < 0.05 to 0 < 0.001) with time in both groups. Prolactin concentrations (basal, suckling stimulated and increment) were higher in the LA group, but consistent significant differences were observed mainly in the increment (p < 0.05 to p < 0.001). Prolactin concentrations significantly (p < 0.01 to < 0.001) decreased with time postpartum in the SA group, but not in the LA group. CONCLUSIONS: Women with longer periods of lactational amenorrhoea maintain higher prolactin concentrations than those with shorter periods of lactational amenorrhoea during the early postpartum period, even when the breastfeeding frequency is reduced. This could be explained by a greater sensitivity of the pituitary lactotrophe to the suckling stimulus in women who have longer periods of lactational amenorrhoea.

Adult↗
PubMed1996

Effect of skim milk supplementation of the maternal diet on lactational amenorrhea, maternal prolactin, and lactational behavior.

Effect of skim milk supplementation of the maternal diet on lactational amenorrhea was studied in 30 pairs of healthy lactating women matched for parity, body mass index, and previous experience of lactational amenorrhea. Supplementation of the maternal diet had no significant effect on the time of resumption of regular menstruation or ovulation, maternal prolactin concentrations, breast-feeding pattern, maternal body mass index, or infant weight. However, the supplemented group breast-fed nearly exclusively (supplemental feeds were introduced but did not exceed 20% of total feeds) for a significantly longer duration (P < 0.05) than did the control group. Previous experience of lactational amenorrhea was significantly positively correlated with the time of resumption of menstruation in the supplemented (P < 0.01) and control (P < 0.05) groups when frequency of breast-feeding, maternal body mass index, and supplementary feeds to the infant were controlled for. Thus, maternal nutritional supplementation does not appear to affect the contraceptive benefit of lactation when the frequency of breast-feeding is not compromised but apparently lengthens the duration of nearly full breast-feeding.

Adult↗
PubMed1994

Effect of Momordica charantia on key hepatic enzymes.

The effect of Momordica charantia on certain key hepatic enzymes was investigated using male Sprague-Dawley rats as the animal model. Fruit juice and seed extract of Momordica charantia were administered orally at a daily dose of 1 ml/100 g body weight for 30 days under light ether anaesthesia while the control group received equivalent amounts of distilled water under identical conditions (n = 10 in each case). Serum gamma-glutamyl transferase (P < 0.001) and alkaline phosphatase (P < 0.01-0.001) concentrations were found to be significantly elevated following oral administration of both the fruit juice and the seed extract. Consistent significant histopathological changes in the liver were not observed in either treatment group although the prevalence of dilatation and/or congestion of the central vein sinusoidal system appeared to be twice as high following fruit juice treatment than in the other 2 groups. Thus, Momordica charantia may either contain hepatotoxins capable of causing cellular damage at the molecular level without causing significant histopathological changes or the plant may have an enzyme inducing effect.

Animals↗
PubMed1994

Prolactin response to suckling in a group of fully breast feeding women during the early postpartum period.

Prolactin response to suckling was studied in a group of fully breast feeding women (N = 58) between 4-6 weeks postpartum. Basal, suckling stimulated and the increment of prolactin showed wide individual variations. Basal prolactin concentrations varied from 140 to 4,600 mIU/l, suckling stimulated prolactin from 400 to 5,600 mIU/l and the increment of prolactin from 40 to 4,160 mIU/l. Basal (p = 0.0395) and suckling stimulated (p = 0.0423) prolactin concentrations significantly increased as the number of night breast feeds increased and the suckling stimulated (p = 0.0218) prolactin concentrations significantly increased as the number of breast feeds/24 h increased. However, the magnitude of the rise in prolactin in response to suckling was not dependent on basal prolactin concentration. Basal, suckling stimulated or the increment of prolactin were not significantly different between subjects having different breast feeding frequencies, when the subjects were grouped according to the number of breast feeds. These differences may be due to the large individual variation in prolactin concentrations seen in women having similar breast feeding frequencies which may arise from individual variations in hypothalamic--pituitary response to suckling.

Adult↗
PubMed1994

Effect of age on serum prolactin concentration in presumably fertile men in Sri Lanka.

OBJECTIVE: To examine possible age related variation in serum prolactin in men. DESIGN: A cross sectional study. SUBJECTS: Healthy married men aged 21 to 85 years with one or more children. MEASUREMENTS: Serum prolactin concentrations measured by immunoradiometric assay. RESULTS: Prolactin concentrations were significantly higher (p < 0.001) from 61 years of age onwards when compared with 31 to 60 years. Prolactin concentrations between 21 to 30 years were significantly higher than between 31 to 50 years (p < 0.05), but lower than between 61 to 70 (p < 0.05) and 75 to 85 (p < 0.01) years. CONCLUSIONS: Serum prolactin concentrations show age related variations in presumably fertile men.

Adult↗
PubMed1993

Synchronous secretion of LH and prolactin during the normal menstrual cycle.

Integrated hourly concentrations of day-time prolactin and LH showed significant positive correlations (p < 0.05-0.001) on the day of the pre-ovulatory mid cycle LH surge (n = 3) and during the mid luteal phase (n = 6) in a group of regularly cyclic women. No correlations between these two hormones were seen during any other stage of the cycle. Consistent significant correlations were not evident between prolactin and oestradiol, prolactin and progesterone, LH and oestradiol or LH and progesterone during any other stage of the cycle.

Female↗
PubMed1992

Biorhythms.

Explore the source record for details and available documents.

Animals↗
PubMed1991

Possible hepatotoxicity of Nigella sativa seeds and Dregea volubilis leaves.

Aqueous extracts of the seeds of Nigella sativa and mature leaves of Dregea volubilis were administered orally under light ether anaesthesia to male Sprague-Dawley rats for 14 days. Key hepatic enzyme concentrations and histopathological changes in the liver in both treatment groups at the end of 14 days were compared with a control group which received distilled water under identical conditions for 30 days and with a group of normal animals. Serum gamma-glutamyl transferase concentrations were significantly increased in both extract groups while serum alkaline phosphatase concentrations were significantly increased following administration of only D. volubilis when compared with either the control or the normal group. Serum alanine aminotransferase concentrations were significantly increased in both extract groups when compared with the normal group but not with the control group. Degenerative changes in hepatocytes were seen following administration of D. volubilis while consistent significant histopathological changes were not evident following administration of N. sativa.

Alanine Transaminase↗
PubMed1991

Time series analysis of biologically active luteinizing hormone concentrations during different stages of the menstrual cycle.

The biologically active luteinizing hormone concentrations (as measured by testosterone production by mouse Leydig cells in response to LH) were measured in integrated hourly blood samples collected over 24-hour study periods during different stages of the menstrual cycle from a group of regularly cyclic women. Time series analyses were used to analyse the ultradian rhythms in each individual 24-hour LH profile. Fast Fourier transform (FFT) showed the presence of several ultradian rhythms with different periodicities (varying from 4.4 to 22 hours) in most of the LH profiles. In some of the LH profiles several ultradian rhythms appeared to co-exist. The commonest significant rhythm as detected by the FFT had a periodicity of 7-9 hours during both the follicular phase (40% of the subjects) and the mid cycle (50% of the subjects) and a periodicity of 5-7 hours during the luteal phase (44% of the subjects).

Female↗
PubMed1990

Effect of Momordica charantia fruit juice on streptozotocin-induced diabetes in rats.

The oral hypoglycaemic activity of Momordica charantia fruit juice was investigated in rats with streptozotocin-induced diabetes. Oral administration of the juice (10 ml/kg for 30 days) did not show a significant effect, either acute or cumulative, on the ability to tolerate an external glucose load. The glycosylated haemoglobin concentrations were significantly elevated in both juice-treated and untreated diabetic rats and there was no significant difference between the two groups. Viable beta-cells capable of secreting insulin upon stimulation appear to be required for M. charantia to exert its oral hypoglycaemic activity.

Administration, Oral↗
PubMed1989

A rise in the biologically active LH: immunologically active LH (B/I) ratio during the normal luteal phase.

Biologically active (bio) LH concentrations and immunologically active (immuno) LH concentrations were measured in integrated hourly blood samples collected over 24 h study periods (n = 27) and in 5 min blood samples collected over 2 h study periods (n = 21) during different stages of the menstrual cycle in a group of regularly cyclic women. Episodic fluctuations were seen in both the bio LH and immuno LH concentrations in hourly as well as in 5 min data series. However, there was no consistent correlation between episodes of bio LH and immuno LH. Mean B/I ratio over the 24 h study periods as well as over the 2 h study periods were significantly higher during the luteal phase than during either the follicular phase (p less than 0.002) or the mid cycle (p less than 0.02).

Female↗
PubMed1989

Prolactin concentrations during the normal menstrual cycle: rhythms within rhythms.

Prolactin concentrations were measured in frequent blood samples collected over a 2 h period randomly distributed during day and night, during the follicular and the luteal phases of the normal menstrual cycle in women. Episodic fluctuations in prolactin concentrations were observed throughout the 24 h period and the pattern of these fluctuations appeared to vary depending on the time, and sleep wake state. Thus a changing pattern of the 'primary pulse' of prolactin may be responsible for the time related and sleep related changes in prolactin during the 24 h period.

Circadian Rhythm↗
PubMed1985

Early evening prolactin rise in women with regular cycles.

Prolactin concentrations were measured in hourly integrated blood samples collected over 24 h in normally cyclic women during the follicular (N = 8) and the luteal (N = 7) phases of the menstrual cycle. Prolactin concentrations were increased during the evening in all the subjects when compared with the rest of the day-time wake-period. This rise was unrelated to sleep, and peak concentrations were seen at 20:00 h. During the luteal phase the magnitude of this evening rise of prolactin was significantly greater (P less than 0.02 at 19:00 h and P less than 0.001 at 20:00 h) when compared with the follicular phase, and was only slightly smaller than the magnitude of the sleep-induced prolactin rise. It is therefore suggested that there may be an intrinsic rhythm in prolactin secretion apart from the sleep-induced rise.

Adult↗
PubMedDate not supplied

Serum FSH, LH, and testosterone concentrations in presumably fertile men: effect of age.

OBJECTIVE: Delineation of change in male hormone and gonadotropin levels from age 21 to 85. SUBJECTS: Healthy married volunteers with one or more children. METHODS: A 5-mL venous blood sample, serum separated within one hour; testosterone measured by direct RIA, FSH and LH by immunoradiometric assay and magnetic separation. RESULTS: FSH significantly higher from 6th decade, LH from 7th decade; testosterone lower from 6th decade. CONCLUSIONS: Apparently, a rise in FSH and reduction in testosterone precede a rise in LH concentration.

Adult↗