Kosin Amatayakul
Chiang Mai University
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Featured researches published by Kosin Amatayakul.
The Journal of Pediatrics | 1978
Raymond L. Hintz; Robert M. Suskind; Kosin Amatayakul; Ousa Thanangkul; Robert E. Olson
This study was undertaken to define the interrelationships of somatomedin, growth hormone, and an inhibitor of SM in protein-calorie malnutrition. Twenty-seven patients, eight to 60 months of age, were studied. Twenty-one well-nourished children acted as controls. SM was significantly depressed at Days 2 and 8 (p less than 0.01) but was not different from controls at Day 29 and 50. In ten out of 27 Day 2 samples and six out of 27 Day 8 samples an inhibitor was identified. When SM values were compared to simultaneous hGH levels, there was an inverse relationship. The low SM levels in the face of markedly elevated hGH levels suggests a functional block in the synthesis and/or release of SM.
Contraception | 1980
Kosin Amatayakul; Boonlong Sivasomboon; Ousa Thanangkul
Twelve non-lactating Thai women using the injectable contraceptive medroxyprogesterone acetate (DMPA) were studied in order to elucidate the mechanism of weight gain frequently seen among DMPA users. The study design included repeated estimations of body fluid compartments (total, extracellular and intravascular) and of nitrogen metabolism, as well as anthropometric measurements. The mean weight remained constant in this group of women after one year of treatment. But 25% of them demonstrated a mean weight gain of 6.05 kilograms, while another 25% showed a mean weight loss of 3.50 kilograms. None of the subjects (including those who gained and lost weight) showed significant changes in her fluid compartmental size, creatinine excretion rate, or nitrogen metabolism. However, skin-fold thicknesses were positively correlated to body weight changes. It can be concluded that medroxyprogesterone acetate when used as injectable contraceptive does not appear to have significant anabolic or fluid retaining properties, and that weight gain appears to be associated mainly with fat deposition.
British Journal of Nutrition | 1992
D.A. Jackson; Stella M. Imong; Lumduan Wongsawasdii; Adung Silprasert; Sakda Preunglampoo; Posri Leelapat; Robert Drewett; Kosin Amatayakul; J. D. Baum
Current infant feeding guidelines recommend exclusive breast-feeding until the infant is about 4 months old to reduce the risks of early termination of breast-feeding, undernutrition and infection. In many societies, however, supplementary foods are given well before 4 months of age. The present paper describes weaning practices, factors associated with early supplementation and the effects of supplementation on duration of breast-feeding in a random sample of sixty northern Thai breast-fed infants studied prospectively from birth to 2 years of age. Composition of supplementary foods, energy and protein intake from supplements and changes in the supplementary diet with increasing infant age are also described. Rice-based foods were given from soon after birth; 81% of the sample had received supplements by 6 weeks of age. Early supplementary feeding was significantly associated with rural residence, large household size, maternal employment in agriculture and maternal age. Girls and infants with lower birth weights tended to be supplemented earlier. Despite early feeding of supplements, breast-feeding was prolonged, with median duration of 12 months. Early introduction of supplements and quantity of supplements consumed in the first 3 months were not associated with duration of breast-feeding. However, mothers who gave infant formula as the first supplementary food stopped breast-feeding slightly earlier, as did younger mothers living in households with more children.
Contraception | 1980
Kosin Amatayakul; Boonlong Sivassomboon; Ratree Singkamani
Proteins (total, albumin, globulin and their subfractions), carbohydrate (intravenous glucose tolerance test), lipids (serum cholesterol, triglycerides and phospholipids), and liver function tests (alkaline phosphatase, lactic dehydrogenase and aspartate aminotransferase activities in the serum, bromsulphathalein retention test and serum bilirubin) were studied in 12 non-lactating healthy Thai subjects before, and subsequently at 3 weeks and 3, 6, 9 and 12 months after the initiation of treatment with injectable medroxyprogesterone acetate (150 mg I.M. every 90 days). Serum protein and lipid levels, and the results of liver function and I.V. glucose tolerance tests, remained unchanged in all subjects throughout the one-year study period. However, a significant and persistent increased insulin level was noted in all subjects, after initiation of the hormone treatment, during the first thirty minutes of intravenous glucose load. It is concluded that injectable medroxyprogesterone acetate used as a contraceptive agent does not interfere with glucose tolerance, lipid and protein metabolism, and that the liver function remains normal during its administration.
British Journal of Nutrition | 1988
Dorothy A. Jackson; Stella M. Imong; A. Silprasert; S. Preunglumpoo; Posri Leelapat; Y. Yootabootr; Kosin Amatayakul; J. D. Baum
1. The present study assesses the accuracy with which mean 24 h breast-milk composition can be estimated if milk samples can only be collected during the daytime. 2. Twenty-five northern Thai mothers, feeding their infants on demand, were studied in their homes for 24 h. All feeds were test-weighed and 0.5 ml pre- and post-feed expressed milk samples taken at each feed. 3. If daytime sampling was restricted to two breast-feeds, it was found that the best estimate of 24 h fat concentration was given by two randomly chosen daytime feeds, predicting 24 h fat concentration with 95% confidence limits of +/- 7.0 g/l (equivalent to 21% of mean 24 h fat concentration). 4. Alternative sampling methods using the mean fat concentration of the feed after 08.00 hours and after 18.00 hours, or the first two feeds after 12.00 hours, predicted fat concentration with 95% confidence limits of +/- 9.7 g/l and +/- 8.9 g/l (28 and 26% of mean 24 h fat concentration) respectively. 5. If well-tolerated by mothers, it would be preferable to sample all daytime feeds, since this reduces the 95% confidence limits to +/- 3.3 g/l, equivalent to 10% of the mean 24 h fat concentration.
Acta Obstetricia et Gynecologica Scandinavica | 1987
Kosin Amatayakul; Teraporn Vutyavanich; Orasri Tanthayaphinant; Sodsai Tovanabutra; Yupadee Yutabootr; Robert Drewett
Plasma prolactin and cortisol levels were measured in mothers breast feeding with or without the use of a thin latex nipple shield, and in mothers wearing a nipple shield but who were not nursing. Suckling duration and milk transfer were also recorded. Suckling duration ranged between 6 and 31 min, being significantly correlated with prolactin levels 40 to 120 min after the feed started. At the latter time, baseline prolactin level and time spent nursing accounted together for most of the variance in prolactin levels: R2 was 0.79 and 0.82 at 90 min and 120 min respectively. Prolactin was released as usual when the shield was in place: levels were not significantly different from levels without the shield. Suckling duration was also unaffected by the shield, but milk transfer was significantly reduced. Cortisol was not released by using the shield, and the shield alone (without suckling) did not release prolactin. The thin latex nipple shield has therefore no untoward effect on the release of these hormones during nursing.
Early Human Development | 1989
Robert Drewett; M.W. Woolridge; D.A. Jackson; Stella M. Imong; Ampica Mangklabruks; Lumduan Wongsawasdii; Pien Chiowanich; Kosin Amatayakul; J.D. Baum
Relationships between nursing patterns, supplementary food intake and breast-milk intake were examined in a group of 52 Thai babies under 1 year of age. All data were collected over two consecutive days, 24 h/day. Total sucking time (min/day) and supplementary food intake (kcal/day) were significant predictors of breast-milk intake after allowing for the age of the baby: R-squared is 0.32 for sucking time and 0.39 for supplementary food intake. The two variables were themselves correlated (r is -0.47). The number of breastfeeds per day and their mean duration was determined for each case, counting each episode of attachment to the breast as a separate feed. Number and mean duration of breastfeeds were then evaluated as predictor variables. The duration of feeds had no predictive power. Number of feeds was linearly related to milk intake and combined with age was as good a predictor of milk intake as total sucking time (with R-squared 0.34). These results suggest that a simple count of breastfeeds is as valuable as more complex measures of sucking duration in predicting to breast-milk intake.
Early Human Development | 1987
Dorothy A. Jackson; M. W. Woolridge; Stella M. Imong; C.N. McLeod; Y. Yutabootr; L. Wongsawat; Kosin Amatayakul; J. D. Baum
The automatic sampling shield uses the negative pressure exerted by the breast-feeding baby during sucking to withdraw a series of small samples from the milk stream. Shield performance was studied at four feeds for each of 13 babies. Acceptance of the shield was good (96% of feeds) and samples were obtained in 88% of feeds. Sample weight was large enough for micro-biochemical analysis of composition (median weight 1.3 g), without depriving the baby of important amounts of milk (median percentage of weight of milk intake was 4.3% and sample weight was less than 5 g in all cases). The shield should sample a constant proportion throughout the feed, in order to obtain a sample that is representative of the infants nutrient intake. Fractional test-weighing of feeds showed a tendency for a larger proportion of the feed to be collected at slower flow rates. Modelling on the basis of the observed flow profiles in conjunction with a theoretical fat concentration profile showed that the observed disproportionality would have over-estimated fat intake by a mean of 2.6% per feed (S.D.9.1 range -18.9% to + 16.9%). Using the shield in random sequence at two out of the first four feeds after 0800 h, showed that an infants mean milk intake with the shield was on average 32% less than on control feeds. Allowing for possible compensation by the infant when control feeds followed low shield intakes, mean milk intakes with the shield were 17% smaller than without the shield.
Journal of Pediatric Gastroenterology and Nutrition | 1989
Stella M. Imong; Dorothy A. Jackson; Lumduan Wongsawasdii; Somsri Ruckphaophunt; Antika Tansuhaj; Pien Chiowanich; M. W. Woolridge; Robert Drewett; J. D. Baum; Kosin Amatayakul
A random sample of 52 mothers and infants from a rural area of Northern Thailand were studied in their homes for 48 h. Infants were breast fed on demand. Daytime feeds were test weighed with electronic averaging balances and nighttime intake estimated using a new method, Indirect Test Weighing (23,24). All feeds, both day and night, were timed to the nearest minute. Other variables measured by direct observation were infant weight, and supplementary food and water intake. Mean 24-h breast milk intake was 579 g (range 78–1,011 g) with a median between day coefficient of variation of 8.8%. The proportion of 24-h breast milk intake consumed at night ranged from 8 to 91%, and increased with increasing infant age. Significant positive associations were found between breast milk intake, and sucking time and infant weight. There were significant negative associations between breast milk intake and age, and supplementary food and water intake.
Contraception | 1984
Kosin Amatayakul; Chumnong Uttaravichai; Ratree Singkamani; Somsri Ruckphaopunt
The effect of combined oral contraceptives containing 158 micrograms of levonorgestrel and 38 micrograms of ethinyl estradiol on vitamin B-1, B-2, B-6, B-12, folates, vitamin A, carotenoids, vitamin E and tryptophan load test was studied in a group of 34 healthy non-lactating women. This was compared to an identical study conducted in another group of 19 subjects who used IUCDs for contraception, and also in two other groups of subjects who were given an additional multivitamin preparation on a daily basis (33 subjects) and on the days when OC was not taken (29 subjects). Assessments were made prior to, and during the third week of the 4th, 7th and the 13th cycles of OC treatment. Urinary xanthurenic acid excretion (XA), plasma vitamin A and the folate content of the sera and red blood cells were significantly increased by OC treatment, although this excessive XA excretion was adequately corrected with 18 mg of daily vitamin B-6 supplementation. The metabolism of the rest of the vitamins was not significantly altered by OC usage. This suggests that a routine use of multivitamin supplement may not be necessary.