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Biomedical subjects

L Lebel

Publications and source records attributed to L Lebel.

At least 19 recordsLinked to original sources
PubMed2000

Urinary calcium excretion in healthy Thai children.

The objective of this study was to determine age-specific reference values for urinary calcium/creatinine ratios (UCa/Cr) of children in southern Thailand. Non-fasting urine samples were collected from a random population of 488 healthy children (282 males, 206 females) ranging in age from 17 days to 15 years. Samples were divided into six groups by age. Subjects whose calcium levels exceeded the 95th percentile within each age group were classified as having hypercalciuria. Pyuria, hematuria, proteinuria, urinary sodium, and potassium levels in children with normal UCa/Cr were compared with levels in children with high UCa/Cr. The 95th percentiles for UCa/Cr (mg/mg) by age were: <6 months, 0.75; 6 months to <12 months, 0.64; 12 months to <2 years, 0.40; 2 years to <5 years, 0.38; 5 years to <10 years, 0.29; and 10 years to <15 years, 0.26. Pyuria, hematuria, and proteinuria were no more prevalent in the 22 children with hypercalciuria than in children with normal urinary calcium levels. Urinary sodium/creatinine ratios (UNa/Cr) and urinary sodium/potassium ratios (UNa/K) were correlated with UCa/Cr (r=0.41, P<0.0001 and r=0.24, P<0.0001, respectively). Urinary potassium/creatinine ratios (UK/Cr) were not (r=0.05, P>0.1)). Children with high UCa/Cr ratios also had higher UNa/Cr and UNa/K (5.6+/-7.1 vs. 2.6+/-1.5, P<0.001 and 5.4+/-2.3 vs. 2.5+/-0.23, P<0.05, respectively). The study established reference values for random, non-fasting UCa/Cr for healthy Thai children and indicated that urinalysis is not a good indicator of hypercalciuria.

Adolescent↗
PubMed1999

Sequence variants of the sarco(endo)plasmic reticulum Ca(2+)-transport ATPase 3 gene (SERCA3) in Caucasian type II diabetic patients (UK Prospective Diabetes Study 48).

AIMS/HYPOTHESIS: Type II (non-insulin-dependent) diabetes mellitus is a common heterogeneous metabolic disorder of largely unknown genetic aetiology. The sarco(endo)plasmic reticulum Ca(2+)-transport ATPase (SERCA) plays an important part in the glucose-activated beta-cell Ca(2+) signalling that regulates insulin secretion. Impaired function and expression of SERCA have been shown in islets of Langerhans from diabetic animal models and have also been associated with beta-cell apoptosis. Thus, the SERCA3 encoding gene is a plausible candidate for a primary pancreatic beta-cell defect. METHODS: In this study, the entire coding and the promoter regions of SERCA3 gene were screened by single-strand conformation polymorphism analysis in white Caucasian Type II diabetic patients. RESULTS: We found four rare missense mutations [Exon 4: Gln(108)-->His (CAG-->CAT), Exon 14: Val(648) -->Met (GTG-->ATG) and Arg(674)-->Cys (CGC--> TGC), and Exon 15: Ile(753)-->Leu (ATC-->CTC)]. The patients with Gln(108)-->His, Val(648)-->Met and Arg(674)-->Cys mutations, which may affect the E1P-E2P transition of SERCA3 during its enzyme cycle, had normal body weight with marked hyperglycaemia and beta-cell dysfunction. That is an unusual phenotype only found in 6 % of the Type II diabetic patients recruited for the UK Prospective Diabetes Study. In addition, five silent polymorphisms, six intron variants and two polymorphisms in the 3' untranslated region of exon 22 were found with similar frequency in diabetic and control subjects. CONCLUSION/INTERPRETATION: Our result suggests that in white Caucasians, the SERCA3 locus possibly contributes to the genetic susceptibility to Type II diabetes [Diabetologia (1999) 42: 1240-1243].

Calcium-Transporting ATPases↗
PubMed1999

School performance and weight status of children and young adolescents in a transitional society in Thailand.

OBJECTIVE: To study the association between current or previous weight status and school performance among children and young adolescents of Hat Yai municipality, southern Thailand. DESIGN: Cross-sectional and longitudinal study. SETTING: Primary and secondary schools of Hat Yai municipality, southern Thailand. SUBJECTS: 1207 grades 3-6 and 587 grades 7-9 students. MEASUREMENTS: Body mass index (BMI, kg/m2) calculated from weight and height measurement of subjects in 1992 and 1994; parental education level and occupation, and monthly income, by questionnaire performed in 1992; grade-point-average (GPA) and grades of mathematics and Thai language from the school records of final examinations in 1994. RESULTS: Overweight subjects (BMI value > 85th percentile of the NHANES-I data for age and gender) in grades 7-9 had a mean GPA 0.20 point (95% confidence internal (CI) = 0.04, 0.37) lower than that of the normal weight children after controlling for gender, age, school and grade. They were twice more likely to have low grades (lower than 2 on the scales of 0-4) of mathematics and Thai language than normal weight children. There were no associations between GPA or individual subject grades and previous BMI status in 1992. Children in grades 7-9 who became overweight over the two years, had a mean GPA of 0.48 point lower than those who did not become overweight (95% CI = 0.12, 0.84). In grades 3-6 subjects, however, becoming overweight had no effect on GPA and individual subject scores. CONCLUSIONS: Our study showed that being overweight and becoming overweight during adolescence (grades 7-9) was associated with poor school performance, whereas such an association did not exist in children (grades 3-6).

Adolescent↗
PubMed1997

Evaluation of various models of hyaluronan kinetics for assessment of liver function.

The purpose of this study of various models of hyaluronan kinetics has been to find the most appropriate model for estimation of parameters which characterize liver endothelial cell function. Five theoretical models for serum hyaluronan distribution and elimination were evaluated by computer analysis of serial measurements of the mass concentration of hyaluronan in serum following an intravenous bolus dose. Three of the models were based on one-compartment distribution of intravenously injected hyaluronan. Model 1A, with assumed first-order elimination, was found to be compatible with measured data and had identifiable parameters. Model 1B, with assumed non-linear Michaelis-Menten kinetics, was also found to be compatible but the Michaelis-Menten constant (K(m)) was not well determined. In model 1C, with non-linear Michaelis-Menten elimination kinetics, K(m) was set to a fixed value of 340 micrograms l-1, and the remaining parameters were well determined and the model was found to be compatible. Two models with an assumed two-compartment distribution of intravenously injected hyaluronan, were not acceptable due to unidentified parameters not discriminating between patients and healthy persons. In conclusion, model 1C, with one-compartment distribution and non-linear Michaelis-Menten kinetics, best fulfilled the criteria of validity and was accepted for further evaluation of clinical materials.

Adult↗
PubMed1997

Djenkol beans as a cause of hematuria in children.

BACKGROUND: Djenkolism is djenkol bean poisoning, characterized by acute renal failure, urinary obstruction and spasmodic pain. The effects of djenkol bean consumption on the urinary tract without overt symptoms and long-term outcome are not established. This paper examines the association between djenkol bean ingestion and urine abnormalities in school children. METHOD: 609 school children aged 7-11 years in five urban Hat-Yai schools were interviewed, and had their urine analyzed. All children included in the study had normal blood pressure for age, no illness (including respiratory tract symptoms) and were not taking medication. RESULTS: 78% of the children had a history of eating djenkol bean and of these 31% had done so in the past 24 h. Children with hematuria were almost four times (crude odds ratio = 3.7) as likely to have a history of eating djenkol beans as those with normal urine. Crystaluria and pyuria were not significantly more common among those eating the beans. The risk of having hematuria did not change with increasing consumption, or time since last eaten, or type of preparation even after adjustment for sex and age. CONCLUSION: Djenkol bean consumption may be defined as one of the probable causes of hematuria in the area where the djenkol tree grows.

Acute Kidney Injury↗
PubMed1996

Risk factors for cardiovascular disease in obese and normal school children: association of insulin with other cardiovascular risk factors.

OBJECTIVE: To investigate the level of insulin and other known cardiovascular risk factors in school children and their association with obesity. DESIGN: Cross-sectional study. SUBJECTS: 123 normal and 116 obese school children categorized by weight-for-height, mean age: 10.2 and 10.5 years old respectively. MEASUREMENTS: Family histories of diseases by questionnaires; blood pressure (BP) and waist and hip circumferences by measurements; fasting blood for glucose, insulin, total cholesterol, HDL-cholesterol and triglycerides. RESULTS: The numbers of boys in the normal and obese group were 65 and 58, those of the girls, 53 and 63 respectively. The obese group was more likely to have family histories of obesity, high blood pressure and diabetes; had significantly greater waist-hip-ratio (WHR), higher systolic and diastolic BP, lower HDL-cholesterol, higher triglyceride and fasting insulin levels (with fasting blood sugar in the normal range) than the normal weight group. In a crude analysis, insulin levels were positively correlated with obesity, systolic BP, WHR, age and triglycerides and negatively associated with male gender and HDL-cholesterol. After adjustment using multiple regression, only obesity status, age, gender and triglycerides still remained significantly associated with insulin level. Limitation of utilizing family disease history report for identification of children at risk was discussed. CONCLUSION: These findings suggest that risk to coronary heart disease and hypertension through insulin resistance already operates in school-aged children.

Analysis of Variance↗
PubMed1996

Incidence and risk factors for carbohydrate intolerance in Thai infants with acute diarrhea: an outpatient-based study.

Until recently, information concerning carbohydrate intolerance complicating acute infantile diarrhea of outpatients in Thailand has been lacking. This prospective study was undertaken to determine the incidence and risk factors of secondary carbohydrate intolerance in outpatients. Of 197 well-nourished infants with acute diarrhea who were seen at the outpatient department of Songklanagarind Hospital between July 1991 and June 1992, 62 infants (31.3%) had carbohydrate intolerance, and 7 of the 62 (3.5%) also had acquired monosaccharide intolerance. The clinical characteristics that predicted infants with carbohydrate intolerance were : a low bodyweight relative to the length, dehydration (OR 4.55, 95% CI 1.1.5-17.9), the presence of mucus in diarrheal stools (OR 2.79, 95% CI 1.23-6.32) and rotavirus infection (OR 3.49, 95% CI 1.20-10.18).

Carbohydrate Metabolism, Inborn Errors↗
PubMed1995

Hepatic extraction of hyaluronic acid in porcine peritonitis.

The hepatic extraction of hyaluronic acid (HA) was studied in porcine fecal peritonitis in two groups of animals given various amounts of volume substitution. There was a progressive decrease in hepatic blood flow (QH) and a corresponding increase in the plasma concentration of HA in arterial blood over a 5-hour observation period, less pronounced in animals given more volume substitution. While hepatic clearance of HA decreased, the extraction ratio over the liver was not altered. The extracted amount of HA, which at steady state reflects the turnover of HA, was also unchanged. There was a significant correlation between QH and arterial HA concentration (r = 0.57; p < 0.05). The data suggest that the arterial HA concentration in sepsis reflects QH rather than an altered ability of the liver to eliminate HA.

Animals↗
PubMed1995

Goiter in Thai schoolchildren: study in Hat Yai, southern Thailand.

Examination for goiter was performed in 6,035 schoolchildren (2,899 girls, 3,136 boys), aged 8-17 years, from primary and secondary schools in Hat-Yai municipality, Songkhla province. Goiter was detected in 355 children (combined prevalence 6%; 232 or 8% in girls, 123 or 4% in boys). Of the 355 children with goiter, 214 (60%; 148 girls, 66 boys) participated in the study, and had blood drawn for free thyroxine (FT4), triiodothyronine (T3), thyroid stimulating hormone (TSH), and thyroid antibodies. All had urine collected for iodine excretion. The diagnoses of goiter were as follows: simple goiter in 192 (89.8%; 129 girls, 63 boys); juvenile autoimmune thyroiditis in 18 (8.4%; 16 girls, 2 boys); Graves' disease in 2 girls (0.9%); thyroid adenoma in 1 boy (0.45%), and ectopic thyroid in 1 girl (0.45%). Acquired hypothyroidism was found in 4 out of 18 children with juvenile autoimmune thyroiditis (22.2%). Iodine deficiency disorder was not evident in children examined shown by high urinary iodine excretion of more than 50 mcg/gm creatinine (mean 298, range 70-630). In conclusion, simple goiter is a common occurrence in children and adolescents in Southern Thailand. Juvenile autoimmune thyroiditis should be identified and differentiated from simple goiter as it is the most common cause of acquired hypothyroidism. Iodine deficiency is not evident in Southern Thailand, at least in the urban areas of a large city.

Adolescent↗
PubMed1995

Ages at thelarche and menarche: study in southern Thai schoolgirls.

Ages at thelarche and menarche have been studied by a status quo method in 3,029 Thai schoolgirls in Hat Yai municipality. The median ages at thelarche and menarche estimated by probit analysis are 9 years 11 months, and 12 years 5 months, respectively. Declining in ages of thelarche and menarche is observed and can be explained by improvement in nutritional status and higher living standards.

Adolescent↗
PubMed1994

Kinetics of circulating hyaluronan in humans. 4.

The elimination of intravenously injected hyaluronan (HA) from the blood was investigated in 12 healthy volunteers. Three consecutive 30 min infusions of HA were given, separated by 90 min washout periods. Blood samples were taken before, during and after each infusion and the plasma HA concentration was determined. The deposition of HA was modelled according to a Michaelis-Menten kinetic model which included natural synthesis of HA. Km and Vmax was estimated to 0.34 +/- 0.13 microgram ml-1 and 3.48 +/- 0.97 microgram min-1 kg-1 b.w., respectively. The endogenous input was calculated to be 24 +/- 11 micrograms min-1 and was found to correlate to the age of the subjects (P < 0.05). As the baseline HA concentration was 0.031 +/- 0.21 microgram ml-1, the rate of elimination was linear in the normal concentration range. The calculated Vd was about 75% higher than a weight-estimated plasma volume. The total amount of HA excreted by the kidneys during the study period was 394 +/- 77 micrograms, which corresponded to approximately 1.7% of the total input of HA into the circulation during the experiment.

Adult↗
PubMed1991

Sodium hyaluronate increases vascular ingrowth in the rabbit ear chamber.

The rabbit ear-chamber model was used to study the effect of sodium hyaluronate (NaHe, Healon) on the rate of ingrowth of vascular structures of healing granulation tissue. The chamber area covered by granulation tissue was determined by in-vivo microscopy at regular intervals during a period of 32 days. Daily injections of 1% NaHe into the ear chamber, 50 microliters from day 0 to day 7 and 25 microliters from day 8 to day 21, significantly inhibited ingrowth as observed between days 20 and 26, compared with buffer-injected controls. There was no difference between the latter and non-injected chambers. Intermittent injections of 1% NaHe, 50 microliters on days 1 and 5 and 25 microliters on days 9, 13 and 22 significantly increased the ingrowth as observed between days 6 and 18. It was noted that wound macrophages internalized fluorescein-labelled NaHe. The inhibitory effect of daily injections on angiogenesis was probably due to physical hindrance caused by the NaHe. The stimulatory effect of intermittent administration of NaHe on angiogenesis may have several explanations, including activation of macrophages and their release of angiogenetic factors.

Animals↗
PubMed1989

A pharmacokinetic model of intravenously administered hyaluronan in sheep.

Hyaluronan (HA: hyaluronic acid) is produced in the interstitium and reaches the blood circulation through the lymph. It is rapidly eliminated by means of specific receptors on liver endothelium. The elimination characteristics of intravenously administered HA were studied in 10 conscious sheep at the normal plasma HA concentration by injection of a 3H-labeled tracer and at a very high concentration by an i.v. infusion of unlabeled HA and simultaneous injection of a tracer dose of 3H-labeled HA. At a normal plasma HA concentration (0.12 +/- 0.05 microgram/ml; range, 0.072-0.228 microgram/ml), the apparent T 1/2 of 3H-HA was 5.3 +/- 1.1 min (range, 3.3-6.5 min). At higher plasma concentrations (range, 1.83-3.35 micrograms/ml), the apparent T 1/2 was considerably prolonged (range, 18.2-43.5 min). A one-compartment, nonlinear model was fitted to data obtained from the bolus-infusion study of unlabeled HA. The Michaelis-Menten constant, Km, was 0.12 +/- 0.04 microgram/ml, indicating that a deviation from linear kinetics will occur when the normal plasma concentration is exceeded. The Vmax was 0.062 +/- 0.009 microgram/ml/min. Three-dimensional surface plots showed that the plasma HA concentration and the total hepatic plasma flow influence the apparent metabolic clearance, extraction ratio, turnover, and T 1/2 of intravenously injected hyaluronan. There was a high correlation between T 1/2 as measured by the injected 3H-HA and T 1/2 calculated from the model (r = 0.96).

Animals↗
PubMed1989

Increased lymphatic elimination of interstitial hyaluronan during E. coli sepsis in sheep.

The effect of septicemia on the elimination of hyaluronan (HA) from the lung interstitium was investigated in awake sheep with chronic lung lymph and thoracic duct fistulas. The result was compared with that after elevation of left atrial pressure (LAP). Lymph was sampled before and after a 20-min infusion of Escherichia coli (10(9) bacteria/kg body wt.), after elevation of LAP, or both. Infusion of E. coli caused an increased flux of HA in lung lymph and thoracic duct lymph. After an elevation of LAP, the HA flux in lung lymph was increased to a comparable extent. In animals subjected to an increase in LAP and subsequently to infusion of E. coli, no additive effect on HA flux was seen. The weight-average molecular weight of HA in lung lymph was increased both after sepsis and after elevation of LAP. The findings show that sepsis and elevated transvascular hydrostatic pressure result in increased mobilization of HA from the interstitium. This might partly explain the increased HA concentrations in plasma in clinical sepsis and may also lead to a change in the characteristics of the interstitial matrix in this condition.

Animals↗
PubMed1988

Effect of increased hydrostatic pressure on lymphatic elimination of hyaluronan from sheep lung.

The effects of increased hydrostatic pressure on the concentrations of hyaluronan (hyaluronic acid) in lung lymph and serum were investigated in awake sheep with a cannula in the efferent vessel from the caudal mediastinal lymph node. Lung lymph was sampled at base line [left atrial pressure (LAP) 6.5 +/- 1.7 mmHg] and after two increases of LAP to 25.7 +/- 2.2 mmHg (level 1) and 37.0 +/- 5.1 mmHg (level 2). The lung lymph flow increased from 1.9 +/- 0.5 at base line to 9.3 +/- 2.2 and 15.9 +/- 0.7 ml/30 min, and the lymph-to-plasma concentration ratio of total protein decreased from 0.63 +/- 0.02 to 0.32 +/- 0.04 and 0.32 +/- 0.05 at the two elevated levels of LAP, respectively. The hyaluronan concentration in lung lymph was unchanged, and there was a flow-dependent elimination of hyaluronan from the lung that increased from 23 +/- 8 to 87 +/- 19 and 137 +/- 37 micrograms/30 min, respectively. The lung concentration of hyaluronan was 167 +/- 28 micrograms/g fresh lung, and at base line it was calculated that slightly less than 2% of the lung hyaluronan was eliminated by the lymphatic route in 24 h. If extrapolated to 24 h, the elimination rate of hyaluronan seen during elevated LAP would result in lymphatic elimination of 18% of the lung hyaluronan over this time period. Since hyaluronan is responsible for part of the protein exclusion in the extracellular matrix, it is plausible that washout of interstitial hyaluronan contributes to the decrease in albumin exclusion from the interstitium that occurs after an elevation of LAP.

Animals↗
PubMed1986

Stimulation of wound healing by epidermal growth factor. A dose-dependent effect.

This work was undertaken to study the effects of various doses of locally applied epidermal growth factor (EGF) on developing granulation tissue in rats. Cylindrical hollow sponge implants were used as an inductive matrix for the growth of granulation tissue. In the test groups, the implants were injected daily with a solution containing 0.2, 1, or 5 micrograms of EGF in 0.1% albumin while the implants of the control group were treated correspondingly with the carrier solution only. Analyses of granulation tissue in the sponge cylinders were carried out 7 days after implantation. A stimulatory, dose-dependent effect of EGF on granulation tissue formation was observed: cellularity increased, as evidenced by the elevated amounts of nucleic acids, and accumulation of collagen and glycosaminoglycans was enhanced.

Animals↗
PubMed1984

The inflammatory reaction in healing wounds: the role of polymorphonuclear leucocytes.

The inflammatory process in granulation tissue in full-thickness skin wounds was studied and the role of polymorphonuclear leucocytes (PMNLs) in this process evaluated in an experimental model in the rat. The number of PMNLs in the wound, assessed by determination of the PMNL-specific enzyme myeloperoxidase (MPO) activity in wound exudate, increased from 0.45 U/ml on day 1 after wounding to 0.8 U/ml on day 2, and then remained constant throughout the five days of observation. The concentration of prostaglandin E2 (PGE2) in wound exudate increased progressively from 70 ng/ml on day 1 to 290 ng/ml on day 5. The lack of correlation between these two variables indicated that PMNLs were not the major source of PGE2. Blood flow and albumin extravasation in the granulation tissue were measured, and the relation between these two variables and PMNL accumulation was studied. Rats were rendered neutropenic with an antineutrophil serum, resulting in an 83% decrease in circulating PMNLs and a 61% decrease in granulation tissue MPO activity on day 5, as compared with rats treated with normal rabbit serum. These reductions did not, however, affect either blood flow or albumin extravasation, and no correlation was observed; but when inter-individual variations in the absolute levels of the variables measured were eliminated by calculating in each rat a left-to-right wound ratio, PMNL accumulation correlated well to both blood flow (R = 0.81) and albumin extravasation (R = 0.65). It is suggested that blood flow and albumin extravasation in the granulation tissue are influenced by local PMNL accumulation and, further, that the inflammatory response varies considerably between one animal and another.

Animals↗