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Biomedical subjects

T K Chung

Publications and source records attributed to T K Chung.

101 records · Page 6Linked to original sources
PubMed1991

Safety of L-tryptophan for pigs.

Epidemic eosinophilia-myalgia syndrome (EMS) associated with excess L-tryptophan (Trp) consumption in humans has been declared a major public health problem. The EMS problem has not been observed in pigs, nor has comprehensive pathology associated with EMS in humans been described. Experiments were therefore conducted to evaluate the pathology and effects of excess dietary L-Trp for finishing (79 to 119 kg) pigs and to determine an LD50 of Trp for pigs. In Exp. 1, addition of .1 or 1% Trp to corn-soybean meal diets had no effect on growth performance or leukocyte and relative eosinophil counts or on plasma aspartate transferase, creatine phosphokinase, and lactate dehydrogenase activities. Likewise, untoward pathological effects of Trp feeding were not observed in the animals under study. In Exp. 2, supplementing the basal diet with 0, 2, and 4% Trp caused linear (P less than .05) decreases in weight gain, feed intake, and gain:feed ratio. Mortality could not be produced by acute oral dosing in the LD50 study (Exp. 3), wherein Trp doses between 2.00 and 5.71 g/kg of BW were administered by stomach tube. Vomiting occurred at oral doses greater than 5.71 g/kg of BW. These results suggest that oral ingestion of Trp in pigs is safe and that pigs can tolerate considerable excesses of Trp.

Administration, Oral↗
PubMed1990

L-2-oxothiazolidine-4-carboxylate as a cysteine precursor: efficacy for growth and hepatic glutathione synthesis in chicks and rats.

Chick and rat experiments were conducted to determine the efficacy of L-2-oxothiazolidine-4-carboxylate (OTC) as a cysteine (Cys) precursor for growth and hepatic glutathione (GSH) biosynthesis. Isosulfurous graded increments of OTC and Cys were added to Cys-free purified amino acid diets that were adequate in methionine. Curvilinear responses to both Cys and OTC for chicks and rats were obtained. Hepatic GSH accumulated in chicks only at dietary Cys levels above 0.10%. In rats, hepatic GSH increased linearly as dietary Cys content increased from deficient to adequate and from adequate to excessive. Utilization of OTC by chicks was as efficacious as isosulfurous levels of Cys for growth and hepatic GSH biosynthesis. In rats, OTC was slightly inferior to Cys for growth and hepatic GSH biosynthesis. Exponential regression slope-ratio growth efficacy values for OTC were 78.5% for chicks and 70.2% for rats; multiple linear regression slope-ratio GSH biosynthesis efficacy values were 80.3% for chicks and 83.7% for rats. It is concluded that orally administered OTC is active as a Cys precursor.

Administration, Oral↗
PubMed1990

Nutritive value of oat flour and oat bran.

Oat flour, the by-product resulting from commercial production of oat bran, was analyzed to contain 7.7% moisture, 11% CP, 6% crude fat, 8.8% NDF, 1.56% ash (.10% Ca, .23% P), 4,265 kcal/kg GE, .41% lysine, .36% threonine, .17% tryptophan, .21% methionine and .34% cystine. Chick bioassays revealed that lysine and threonine were the first- and second-limiting amino acids in oat flour. Slope-ratio protein quality assessment indicated that the protein quality of oat flour was similar to that of dehulled soybean meal. True ME (corrected for N retention, i.e., TMEn) of oat flour for adult cockerels was 3,726 kcal/kg. A P bioavailability assay with chicks indicated that the P in oat flour was 59.7% bioavailable relative to a KH2PO4 standard. Oat bran was analyzed to contain 9.7% moisture, 15% CP, 6.2% crude fat, 19.2% NDF, 2.33% ash (.12% Ca, .41% P), 4,316 kcal/kg GE, .59% lysine, .47% threonine, .18% tryptophan, .24% methionine and .44% cystine. Protein quality assessment in chicks indicated that the protein quality of oat bran was similar to that of dehulled soybean meal. True MEn of oat bran was found to be 3,449 kcal/kg. Of the .41% total phosphorus in oat bran, 42.2% was bioavailable, relative to the KH2PO4 standard.

Amino Acids↗
PubMed1990

Phosphorus utilization in chicks fed hydrated sodium calcium aluminosilicate.

Two experiments were conducted to evaluate the effects of hydrated Na Ca aluminosilicate (HSCAS) on P utilization of young broiler chicks. Phosphorus-deficient corn-soybean meal diets containing .36% (.134% available) P and 1% Ca were fortified with 0, .05 and .10% P provided as KH2PO4 (22.8% P) or feed-grade dicalcium phosphate (18.9% P). Diets were available ad libitum to chicks receiving 0, .50 or 1.0% HSCAS during the period 8 to 22 d posthatching. Weight of tibia ash, percentage of tibia ash and bone-breaking force were regressed on supplemental P intake to assess P utilization in the absence or presence of HSCAS. Tibia parameters (ash weight, percentage of ash and bone-breaking force) responded linearly (P less than .01) to P supplementation. Regardless of P source (KH2PO4 or dicalcium phosphate), .5% or 1.0% HSCAS had no effect (P greater than .1) on P utilization. With no supplemental P, tibia parameters also were not affected (P greater than .05) by HSCAS. Phosphorus utilization from dicalcium phosphate was estimated to be 87% as efficient as that observed for KH2PO4. The results suggest that dietary HSCAS does not impair utilization of either phytate or inorganic P.

Aluminum Silicates↗
PubMed1990

Riboflavin requirement of chicks fed purified amino acid and conventional corn-soybean meal diets.

Three experiments were conducted to determine the riboflavin requirement for maximal growth of young chicks. Graded levels of crystalline riboflavin were added to either riboflavin-free, purified amino acid diets or corn-soybean meal diets. Chick growth responses were obtained upon adding riboflavin to both diets. Chicks fed the purified diet required 1.8 mg of riboflavin per kg of diet, but those fed the corn-soybean meal diet required 2.63 mg of riboflavin per kg of diet. Retarded growth and leg paralysis, rather than curled-toe paralysis, were the predominant signs of riboflavin deficiency. Calculations suggested that riboflavin bioavailability in the corn-soybean meal diet was 59.1%.

Amino Acids, Essential↗
PubMed1990

Hydrated sodium calcium aluminosilicate: effects on zinc, manganese, vitamin A, and riboflavin utilization.

Three experiments were conducted to evaluate effects of hydrated sodium calcium aluminosilicate (HSCAS, a phyllosilicate) on Zn, Mn, vitamin A, and riboflavin utilization in young broiler chicks. In Experiment 1, addition of either .5% or 1.0% HSCAS to practical corn-soybean meal diets had no effect (P greater than .05) on total tibia Mn content or total liver vitamin A concentration. Total tibia Zn decreased slightly, but linearly (P less than .05), as level of HSCAS increased. Graded increments of riboflavin (0, .6 and 1.2 mg per kg of diet) were added to a riboflavin-free purified amino acid diet to assess riboflavin utilization as affected by HSCAS in Experiments 2 (.5% HSCAS) and 3 (1.0% HSCAS). Linear growth responses to riboflavin were obtained in the absence and presence of HSCAS. Common intercept multiple-linear regression indicated that riboflavin utilization was not affected (P greater than .05) by .5% or 1.0% HSCAS. The results suggest that .5% or 1.0% dietary HSCAS does not impair Mn, vitamin A, or riboflavin utilization, but that Zn utilization is reduced slightly as a result of HSCAS ingestion.

Aluminum Silicates↗
PubMed1989

Methionine requirement of the finishing pig.

Two pig experiments were conducted using a methionine (Met)-deficient feather meal-corn-soybean meal basal diet (13% CP; 3,400 kcal ME/kg diet, .126% Met, 456% cystine) supplemented with an amino acid mixture (lysine, tryptophan, histidine, threonine and phenylalanine) to determine the Met requirement of finishing pigs between 50 and 80 kg live weight. Using young chicks in a Met bioavailability growth assay and cecectomized adult cockerels in a Met digestibility assay, the Met-deficient basal diet was found to contain .115% bioavailable and .110% digestible Met. These results gave a bioavailability estimate (relative to DL-Met set at 100%) of 91.3 +/- 2.5% and a true digestibility estimate of 87.0 +/- 2.2% for Met in the basal pig diet. In Exp. 1, 21 crossbred pigs averaging 61 kg initially were individually fed diets containing .115, .165 or .215% bioavailable Met for 21 d. Average daily gain and gain:feed ratio increased quadratically (P less than .05) as level of Met increased. In Exp. 2, 30 crossbred pigs averaging 53 kg were individually fed diets containing .115, .135, .155, .175 or .195% bioavailable Met for 27 d. Daily gain and gain;feed ratio responded linearly (P less than .01) as Met level increased. Based on the results of Exp. 2, the bioavailable Met requirement of finishing pigs in the weight range 50 to 80 kg was estimated to be .182% of the diet. Assuming an 88% bioavailability of Met in commercial diets based on corn and soybean meal, the total Met level needed in practice would be .207%. If 55% of the finishing pig's sulfur amino acid need can be furnished by cystine, the total sulfur amino acid requirement would be .45% of the diet.

Analysis of Variance↗
PubMedDate not supplied

Screening psychiatric morbidity after miscarriage: application of the 30-item General Health Questionnaire and the Edinburgh Postnatal Depression Scale.

OBJECTIVE: Psychiatric morbidity affects 48% to 51% of women who have miscarried. This study evaluated the utility of two sample and brief self-report questionnaires in screening psychiatric morbidity after miscarriage. METHOD: One hundred fifty-six subjects completed the 30-item General Health Questionnaire (GHQ), the Edinburgh Postnatal Depression Scale (EPDS), and the Beck Depression Inventory (BDI) 6 weeks after miscarriage. Then there was a blind assessment using the Structured Clinical Interview for DSM-III-R (SCID) to establish psychiatric diagnosis. The criterion validity of GHQ and EPDS were tested against this yardstick diagnosis and the concurrent validity against the BDI scores. The internal consistency of the scales was measured by Cronbach's alpha-coefficient. RESULTS: Both GHQ and EPDS had good sensitivity and specificity in screening for psychiatric morbidity after miscarriage. The concurrent validity and the internal consistency of both scales were satisfactory. The EPDS could only identify those subjects with major depression. The GHQ was longer to perform, but was able to detect both anxiety and depressive disorders. Furthermore, the GHQ had better psychometric properties when compared with the EPDS. CONCLUSIONS: These scales will be particularly useful for nonpsychiatric medical personnel. We recommend routine application of the GHQ 6 to 8 weeks after miscarriage to identify women who may require psychiatric management.

Abortion, Spontaneous↗
PubMedDate not supplied

Screening for postnatal depression using the double-test strategy.

OBJECTIVE: Postnatal depression affects 10% to 15% of women after childbirth. Self-report rating instruments, such as the Edinburgh Postnatal Depression Scale (EPDS), have been developed and administered to postpartum women to facilitate early detection. Most postnatal depression screening scales, however, focus solely on depressive symptomatology. We hypothesized that applying two complementary rating scales of symptoms and functioning as a double test would significantly enhance the positive predictive value of screening. METHODS: A prospective cohort study was conducted at the postnatal clinic of a university teaching hospital. One hundred forty-five Chinese women completed the EPDS and 12-item General Health Questionnaire (GHQ) 6 weeks after delivery. They were then interviewed by a psychiatrist, who used the Structured Clinical Interview for third revised edition of the Diagnostic and Statistical Manual of Mental Disorders, nonpatient version (SCID-NP), to validate the diagnoses. RESULTS: The positive predictive value of the EPDS and GHQ, when administered independently, was 44% and 52%, respectively, at their respective optimal cutoff scores. When the EPDS-GHQ double test was administered, the positive predictive value was significantly increased to 78%. CONCLUSIONS: Simultaneous administration of the EPDS and GHQ can substantially improve identification of women with postnatal depression. This can potentially reduce unnecessary referrals to general practitioners and psychiatrists and may enhance the overall cost-effectiveness of population-wide screening.

Adolescent↗
PubMedDate not supplied

Antepartum depressive symptomatology is associated with adverse obstetric and neonatal outcomes.

OBJECTIVE: The purpose of this study was to examine if depressive symptomatology in pregnancy is associated with adverse obstetric and neonatal outcomes. METHOD: In a prospective observational study, 959 women were followed up longitudinally from early pregnancy to postpartum. The level of depression was measured at baseline (first antepartum visit) and in late pregnancy using the Beck Depression Inventory (BDI). Adverse obstetric and neonatal outcomes were recorded at delivery. RESULTS: Depression in late pregnancy was associated with increased risk of epidural analgesia (33% vs. 19%, p =.01, adjusted RR = 2.56, 95% CI 1.24-5.30), operative deliveries (caesarean sections and instrumental vaginal deliveries) (39% vs. 27%, p =.02, adjusted RR = 2.28, 95% CI 1.15-4.53), and admission to neonatal care unit (24% vs. 19%, p =.03, adjusted RR = 2.18, 95% CI 1.02-4.66). These effects remained significant even when controlled for potential confounders, such as antepartum complications. CONCLUSION: Previous studies have shown that antepartum anxiety or stress was associated with growth retardation, premature delivery, and epidural analgesia. Our findings add to this body of evidence, which together suggest an adverse impact of antepartum psychological morbidity on maternal and neonatal well-being.

Adolescent↗