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Biomedical subjects

S C Ling

Publications and source records attributed to S C Ling.

At least 19 recordsLinked to original sources

Linear and knemometric growth in the early phase of rehabilitation from severe malnutrition.

The relationship between ponderal, linear and lower leg growth in children recovering from severe malnutrition remains unclear. We report on the early growth of 141 severely malnourished Bangladeshi children aged 6 to 36 months of age who were followed for 90 d. Mean (sd) weight for height (WHZ) and height for age (HAZ) catch-up growth z scores over the 90 d were 1.6 (0.85) and 0.47 (0.325) respectively. Mean (sd) lower leg length growth was 10.35 (4.5) mm. Change in HAZ was significantly associated with initial WHZ, but linear growth occurred in the presence of severe wasting and no threshold WHZ score was identified. Lower leg length gain correlated throughout with ponderal indices but with change in HAZ score only after day 45. Only initial WHZ score and maternal height predicted for linear growth and only accounted for 20 % of total variance. We conclude that linear growth occurs early in severely malnourished children but that knemometry behaves as a ponderal index acutely.

Anthropometry↗

Liver disease does not affect lipolysis as measured with the 13C-mixed triacylglycerol breath test in children with cystic fibrosis.

BACKGROUND: Liver disease associated with cystic fibrosis may not only limit the solubilisation and absorption of the products of fat digestion, but also may depress the activity of pancreatic lipase. The purpose of this study was to measure the effect of liver disease on triacylglycerol lipolysis using the 13C-mixed triacylglycerol breath test. METHODS: Forty children with cystic fibrosis took 13C-mixed triacylglycerol with a standard breakfast and the child's normal pancreatic enzyme replacement therapy. Breath samples were collected before and every 30 minutes after ingestion for 6 hours. The cumulative percentage dose of 13C recovered at 6 hours was calculated from sequential measurements of 13C enrichment of breath CO2, measured by isotope ratio mass spectrometry. Liver abnormalities and portal hypertension were defined by ultrasound scan and clinical examination. RESULTS: Twenty-four children had liver abnormalities, including 5 with portal hypertension. No difference was found between cumulative percentage dose of 13C recovered at 6 hours in 16 children with no liver abnormality (mean, 21.4%+/-11.1%), 19 children with liver abnormalities (22.2%+/-10.0%) and 5 children with portal hypertension (20.9%+/-7.1%). CONCLUSION: Intestinal lipolysis is not reduced in cystic fibrosis liver disease when measured using the 13C mixed triacylglycerol breath test. These findings affirm the test's use as an indirect measure of fat digestion that is not affected by inadequate intraluminal bile salts or liver disease.

Adolescent↗

Nutrition in inflammatory bowel disease.

Recent developments concerning nutritional complications of inflammatory bowel disease include a better understanding of disease-associated anorexia and increasing recognition of the interaction of nutrition and cytokines in the pathogenesis of growth impairment of children. Decreased bone mineral density is a multifactorial complication and an increased focus of research. Enteral nutrition continues to play an important role in the therapy of Crohn's disease. The mechanisms whereby specific nutrients, such as n-3 fatty acids, antioxidants, and butyrate, ameliorate inflammation are being elucidated in in-vitro studies, but beneficial effects have yet to be translated into the clinical sphere.

Anorexia↗

The evolution of liver disease in cystic fibrosis.

OBJECTIVES: To describe prospectively the evolution of liver abnormalities in cystic fibrosis (CF), and to assess their impact on nutritional status. STUDY DESIGN: 124 children (61 boys) with CF (median age, 5.4 years; range, 0.1-13.9) were followed longitudinally for a median of four years. Annual clinical examination, biochemistry, and ultrasound assessment were performed. Chrispin-Norman score, anthropometry, and bacterial colonisation of airway secretions were measured at each assessment. RESULTS: At initial assessment, 45% of the patients had no liver abnormalities, 42% had biochemical abnormality, 35% ultrasound abnormality, and 6% had clinical abnormality of the liver. In this cross sectional analysis, abnormal biochemistry was present in 40% of children with ultrasound or clinical abnormalities, but when longitudinal follow up data were analysed, abnormal biochemistry preceded or coincided with abnormal ultrasound or clinical hepatosplenomegaly in three quarters of 53 children developing new abnormalities. Eighty four of 124 children (68%) showed ultrasound or clinical evidence of liver abnormality at some point during the four years of follow up. No association was found between liver disease and nutritional status. CONCLUSIONS: Hepatic abnormality was common in this group of children with CF, was often predicted by intermittent biochemical abnormalities, and was not associated with deterioration in nutritional status.

Adolescent↗

Characterization of granular particles isolated from postsynaptic densities.

We describe here the isolation and biochemical characterization of a population of protein aggregates from the postsynaptic density (PSD) prepared from pig cerebral cortex. The protein constituents of these aggregates are linked together primarily by disulfide bonds. Negative staining electron microscopy revealed that the isolated protein aggregates were granular objects with an average outside diameter of approximately 21 nm and with small protrusions on their surface. The major constituents of the isolated granular aggregates consist of tubulin and an unidentified protein of 70 kDa in size. Small amounts of the alpha subunit of calcium/calmodulin-dependent protein kinase II and subunits of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and NMDA subtypes of glutamate receptors were also detected by immunoblotting. Actin, however, was not found in these granular aggregates. We propose that these granular protein aggregates correspond to the approximately 20-nm-diameter granular particles of the PSD on the basis of their biochemical and morphological characteristics. The spatial arrangement of these granular aggregates relative to other components of the postsynaptic terminal is also postulated here.

Animals↗

Zinc and rehabilitation from severe protein-energy malnutrition: higher-dose regimens are associated with increased mortality.

A randomized, double-blind trial was undertaken to measure the effects of zinc supplementation on catch-up growth in severe protein-energy malnutrition, with particular reference to linear growth. One hundred forty-one children between the ages of 6 mo and 3 y were enrolled after admission to a nutritional rehabilitation unit in Dhaka, Bangladesh, and randomly assigned to receive elemental zinc by mouth, 1.5 mg/kg for 15 d, 6.0 mg/kg for 15 d, or 6.0 mg/kg for 30 d, and thereafter they were followed for a total of 90 d. Anthropometric outcome measures included change in knee-heel length, midupper arm circumference, subscapular and triceps skinfold thicknesses, and change in height-for-age, weight-for-age, and weight-for-height z scores. Higher zinc doses were not associated with significant change in any anthropometric measurement, but mortality was significantly greater in children who received high-dose zinc (6.0 mg/kg) initially as opposed to those who received low-dose zinc supplementation (1.5 mg/kg) (Yates-corrected chi-square P value of 0.033 and a risk ratio of 4.53; 95% CI: 1.09 < risk ratio < 18.8). We conclude that there is no benefit to using high-dose zinc supplementation regimens and that they could contribute to increased mortality in severely malnourished children.

Anthropometry↗

IGF-1.

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Celiac Disease↗

Ontogeny of hepatobiliary secretion: role of glutathione.

The ontogeny of hepatic synthesis and biliary secretion of glutathione was characterized and correlated with hepatic gamma glutamyl transpeptidase, bile flow rate, biliary bile acids and amino acids in Sprague-Dawley rats at 18 days of gestation and postnatally at ages 7, 14, 21, 28 and 54 days. Bile was collected by bile duct cannulation under intraperitoneal anesthesia with nembutal/ketamine. Glutathione, gamma glutamyl transpeptidase and bile acids were analyzed enzymatically and amino acids by high-performance liquid chromatography using established methods. Hepatic glutathione was low in the fetus, but increased to approximate adult levels by 7 days postnatally (2.77 mumol/gm liver). Hepatic gamma glutamyl transpeptidase activity, high in the fetus, declined to adult levels by day 7 (0.03 mumol/mg protein). In contrast, significant efflux of glutathione and its constituent amino acids into bile did not occur until weaning (21 days of age). During weaning, there was a fivefold increase in the biliary glutathione and with a twofold increase in bile flow rate. Biliary bile acids concentration remained constant throughout development, with only a 30% to 50% increase in its secretion rate. The data suggest that the developmentally related increase in bile flow rate was principally a result of the increase in bile acid independent flow from 1.1 microliters/(min.100 gm body wt) in the suckling to 4.3 microliters/(min.100 gm body wt) in the post-weanling animal.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗

Comparison of nonabsorbable markers Poly R-478 and [14C]PEG-4,000 for use in developmental absorption studies.

To determine the utility of Poly R-478, a stable, polymeric dye (MW, 40,000), as a nonabsorbable marker for studies in the developing small intestine, it was validated by comparison to carbon 14-labeled polyethylene glycol, MW 4,000 [( 14C]PEG-4,000) in rats from 14 to 40 days of age. The recovery and quantification of Poly R-478 from biological samples is simple and rapid compared to other nonradioactive nonabsorbable markers. In 40-day-old rats simultaneously given Poly R-478 and [14C]PEG, total recoveries were similar, the percentages of the Poly R-478 dose and the [14C]PEG dose recovered per segment were identical, and taurocholate absorption rates calculated using each marker were comparable. Recovery of Poly R-478 from flushed intestinal segments, determined by a one-step extraction, was equivalent to that of [14C]PEG in 40-day-old rats (96.5 +/- 3.7% versus 102.7 +/- 10.1%; NS) but was superior to that of [14C]PEG in 21-day-old rats (98.0 +/- 6.2% versus 63.4 +/- 5.5%; p less than 0.001) and 14-day-old rats (97.8 +/- 6.7% versus 56.7 +/- 12.6%; p less than 0.001). Within each age group, the distribution of Poly R-478 within the intestine was similar to that of [14C]PEG. In addition, total taurocholate absorption in the presence of Poly R-478 was comparable to that in the presence of [14C]PEG. Complete recovery of Poly R-478 from a suspension of liver particles and from mixtures with two commercial infant formulas was demonstrated in vitro, suggesting that Poly R-478 may be used when foods are present in the intestine.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

A study on the vascular supply of the supraspinatus tendon.

The vascular supply of the rotator cuff in 22 adult shoulders was studied by way of mixture infusion of gelatin and India ink and vascular cast, in combination with Scanning Electronic Microscopy of the vascular pattern in the supraspinatus tendon. It was found that the vessels of the supraspinatus tendon mainly derive from the anterior circumflex humeral and suprascapular arteries. Macroscopically, an avascular zone or critical zone could be seen on the surface of supraspinatus, and the mean distance of the external edge from the osteo-tendinous attachment was 7.8 mm. The area of the avascular zone increased with age.

Arteries↗

Taurocholate transport by brush-border membrane vesicles from the developing rabbit ileum: structure/function relationships.

To examine the ontogenesis of bile acid transport in the rabbit ileum, brush-border membrane vesicles (12- to 20-fold purified) were prepared from 14- to 49-day-old animals. Taurocholate uptake was characterized by the emergence of secondary active, Na(+)-dependent transport at the start of weaning (21 days). Transient intravesicular accumulation (overshoot) of taurocholate occurred at 5-10 s of incubation, and the overshoot maximum increased significantly from 21 days (349.2 +/- 22.4 nmol/mg protein) to 35 days (569.0 +/- 84.3 nmol/mg protein; p less than 0.001), without further increase at maturity (49 days, not equal to 607.6 +/- 136.7 nmol/mg protein). No significant taurocholate active uptake component was noted at 14 days; however, ileal vesicles from sucklings showed carrier-mediated, Na+ D-glucose cotransport. In greater than or equal to 35-day-old rabbits, osmolarity studies at 20 s of incubation showed that only approximately 12% of [14C]taurocholate uptake was secondary to bile acid-to-membrane binding. Conversely, at 20 min, greater than 95% of radiolabel incorporation represented solute bound to the external and/or internal membrane surface. Arrhenius plots establish brush-border membrane taurocholate uptake as an intrinsic, lipid-dependent process, with a slope discontinuity between 24 and 28 degrees C, similar to the membrane lipid thermotropic transition region. Steady-state fluorescence polarization studies (1,6-diphenyl-1,3,5-hexatriene) demonstrate a temporal association between the maturation of taurocholate uptake and age-related decreases in ileal brush-border membrane fluidity. These data indicate that maturation of bile acid secondary active transport in the rabbit ileum may be regulated, at least in part, by changes in brush-border membrane lipid dynamics.

Age Factors↗

Effects of ethinyl estradiol on intestinal membrane structure and function in the rabbit.

Structural and functional properties of the small intestinal microvillus membrane were evaluated in the rabbit after administration of ethinyl estradiol, a synthetic estrogen with a demonstrated propensity to alter hepatic membrane lipid fluidity, and promote cholestasis. In the jejunum, no estrogen-induced changes in microvillus membrane total lipid, cholesterol or phospholipid content were observed. However, the ileal microvillus membrane in estradiol-treated animals demonstrates significant reductions vs. controls (per mg protein) in total lipid (0.55 milligrams vs. 0.89 milligrams) [corrected] and phospholipid (206.7 micrograms vs. 304.91 micrograms) (p less than 0.001) content, as well as modifications in specific phospholipid species. The increase in the ileal microvillus membrane cholesterol: phospholipid molar ratio (0.65 vs. 0.51, p less than 0.05) was associated with a significant decrease in membrane lipid fluidity reflected by an increase in fluorescence anisotropy measurements utilizing diphenyl hexatriene as the fluorophore (r at 25 degrees C = 0.306 vs. 0.282, p less than 0.05). Thermotropic lipid phase transitions, assessed by Arrhenius plots of both fluorescence data and ileal microvillus membrane p-nitrophenylphosphatase activity demonstrate that phase changes occur between and 24 and 28 degrees C in both treated and untreated groups. Within the temperature range studied (40-10 degrees C) no differences from control were observed in microvillus membrane alkaline phosphatase activity following estrogen treatment. These data therefore indicate that ethinyl estradiol-induced effects on microvillus membrane lipid composition and physical properties occur predominantly in the ileum and appear to be related, in part, to specific alterations in the availability of phospholipid following estrogen treatment.

4-Nitrophenylphosphatase↗

Analysis of coronary flow fields in thoracotomized dogs.

A nonlinear theory of pulsatile flow was used to investigate the detailed flow field in the left circumflex coronary artery of anesthetized open-chest dogs. Studies were carried out under a wide range of blood pressures and flow rates induced by intravenous infusions of dipyridamole. The results indicated that (1) the flow profiles, although less blunt than those in the descending aorta, are still nonparabolic, (2) the wall shear in the coronary arteries maintains a high value through diastole, and (3) during intravenous infusions of dipyridamole both coronary flow and wall shear increase. The peak value of the shear stress during these infusions, which reached 360 dynes/cm2, can approach the yield stress value of 400 dynes/cm2 reported by Fry for endothelial cells.

Animals↗