Urinary fluoride levels in children in a single school in Trinidad and Tobago: a preliminary investigation.

OBJECTIVE: To determine urinary fluoride levels in school children in a non-fluoridated area in Trinidad and Tobago. METHOD: Morning urine samples were requested from 750 children aged 5 to 14 years, attending a primary school in the area of St Joseph, north west Trinidad. Urine was collected at home and brought to school in labelled plastic bottles. Urinary fluoride concentration (ppm) was measured using an ion-specific electrode. RESULTS: Urine samples were available for 500 children (67%). Mean age was 8.5 years. Overall mean fluoride concentration was 0.5 ppm +/- standard deviation (SD) 0.27; males (n = 263) were 0.58 ppm +/- 0.28 and females (n = 237) 0.55 ppm +/- 0.27. Children in the 5 to 7-year age group had the highest levels (0.64 ppm +/- 0.33). CONCLUSION: Mean urinary fluoride levels in this sample of school children were low indicating a fluoride intake below the optimum level for caries prevention. Fluoridation programmes may need to be implemented to increase fluoride intake among school children in the study area.

Flow-injection analysis of serum urea using o-phthalaldehyde and naphthylethylenediamine.

An analytical procedure is developed for the determination of urea using flow injection analysis. The methodology is based on the color that develops (lambda(max), 517 nm) when urea reacts with o-phthalaldehyde in the presence of naphthylethylenediamine under acidic conditions. Calibration curves are found to be linear up to 51 mg urea N/dl when the FIA manifold is operated at 42 degrees , utilizing 90-mul samples and a flow-rate of 0.44 ml/min. By manual injection up to 40 samples can be analysed per hour. Recovery yields varied between 95-99%. The within day CV was 0.5-2.2% whereas the day to day CV was 2.1-3.9%. When applied to the analysis of urea in serum samples, excellent correlations (0.998) are obtained when the FIA results are compared with those obtained for the same serum samples analysed by the free urease/Berthelot's and the hospital method (employing the Abbot Bichromatic Analyser). Interferences are observed with sulphur compounds such as sulphanilamide (0.76 mg/dl) as well as with many amino acids but at relatively high concentrations (21 mg/dl).

Ataxia Telangiectasia. A case report.

The case of an eight year old girl with Ataxia Telangiectasia (AT) is described. She presented at seven years of age with gait problems and was found to have the neurological, dermatological and immunological features characteristic of AT along with a history of frequent sino-pulmonary infections. This report highlights the refractory nature of the disease, the difficulties in medical management, and the problems posed by late diagnosis which can compromise patient care. This is a rare inherited form of ataxia which has not been previously reported in West Indian literature.

Immobilization of linamarase and its use in the determination of bound cyanide in cassava using flow injection analysis.

Extracts from the tubers (cortex and parenchyma) and leaves of Manihot esculenta Crantz (cassava) were analyzed for their releasable cyanide content using flow injection analysis incorporating an immobilized linamarase bioreactor. Linamarase was immobilized under very mild conditions to an activated 2-fluoro-N-methylpyridinium Fractogel support. The released cyanide, which was monitored spectrophotometrically at 525 nm using an alkaline picrate reagent, was found to be highest in the cortex and lowest in the parenchyma.

Unusual protein-binding specificity and capacity of aza-arenophilic gels.

A number of synthetic aza-arenophilic gels have been synthesized from Sepharose CL-4B, 3,5-dichloro-2,4,6-trifluoropyridine and 4-dimethylaminopyridine. These show high binding capacities for immunoglobulins and enzymes. Under high-salt buffer binding conditions, IgG can be effectively eluted, essentially free of contamination by BSA, using acidic conditions (pH 2.5) or phosphate buffers (pH 7.4) containing nucleophiles. Enzymes can also be readily adsorbed and desorbed. Thus these gels can be reused as supports for the immobilization of enzymes.

Flow kinetics of beta-galactosidase chemically attached to nylon tubing.

Beta-Galactosidase (EC 3.2.1.23) has been attached covalently to the inner surface of nylon tubing. An experimental study has been made of the flow kinetics for the hydrolysis of o-nitrophenylgalactose, the substrate concentration and flow rate being varied. The results were analyzed in the light of the theoretical treatment of Kobayashi and Laidler, three different methods of analysis being employed. It is concluded that at the lower substrate concentrations and flow rates employed, the reactions are largely diffusion controlled; with increase in flow rate and substrate concentration the width of the Nernst diffusion layer decreases, and there is found to be less diffusion control. The values of Km(app) vary with flow rate VF, being linear in VF-1/3, and the value extrapolated to very high flow rate agrees well with the Km value for beta-galactosidase in free solution. The theory and results are shown to provide guidelines for the design of open tubular heterogeneous enzyme reactors for industrial, biomedical, and analytical applications.

Hydrolysis of D-galactosides in an open tubular lactase reactor.

Lactase (beta-galactosidase) was attached to the inner surface of nylon tubing. Tubes of various lengths were used to bring about the hydrolysis of o-nitrophenyl-beta-D-galactoside and of lactose in skim milk. The results with the former substrate were analyzed in the light of a theoretical treatment of Kobayashi and Laidler (Biotechnol. Bioeng., 16, 99, 1974), with the conclusion that the reaction is intermediate between diffusion-free and completely diffusion-controlled behavior. The results with skim milk show that with a single 46 m tube and continuous circulation, 90% of the lactose is removed within 20 hr. A battery of ten such tubes, with single passage, at a flow rate of 2 cm/sec, would remove more than 99% of the lactose in less than 40 min.

Flow injection analysis of serum urea using urease covalently immobilized on 2-fluoro-1-methylpyridinium salt-activated fractogel and fluorescence detection.

Serum samples were analyzed for their urea content using fluorescence flow injection analysis incorporating an immobilized urease bioreactor and a gas permeable separator. The urease was immobilized under mild and facile conditions to a hydrophilic 2-fluoro-1-methylpyridinium-activated support. The ammonia released as a result of urease-catalyzed urea hydrolysis diffused through a gas permeable membrane into a constant stream of o-phthaldehyde solution to form a highly fluorescent product with lambda ex at 340 nm and lambda em at 455 nm. Up to 25 serum samples can be analyzed per hour. The within-day coefficient of variation (CV) was 1.12% and the day-to-day CV was 1.25% for serum containing 10.50 mg urea nitrogen dl-1. The bioreactor shows excellent storage (at 4 degrees C) and operational stabilities (at 37 degrees C).

Flow injection analysis of lactose using covalently immobilized beta-galactosidase, mutarotase, and glucose oxidase/peroxidase on a 2-fluoro-1-methylpyridinium salt-activated Fractogel support.

Milk samples were analyzed for their lactose content using flow injection analysis and incorporating immobilized beta-galactosidase or beta-galactosidase/mutarotase and glucose oxidase/peroxidase bioreactors. These enzymes were immobilized, under mild conditions, on to a 2-fluoro-1-methylpyridinium salt-activated Fractogel support. The use of a phosphate buffer (0.15 M) was found to facilitate the rapid mutarotation of alpha-D-glucose and hence could obviate the need for the more expensive mutarotase. The chromogenic agents of choice for monitoring the reaction were 3-methyl-2-benzothiazolinone hydrazone and 3-dimethylaminobenzoic acid. Linearity was observed over the concentration range 16-160 micrograms/ml using lactose standards (r = 0.996). Between 30 and 40 milk samples/h can be analyzed. Comparisons are made with existing HPLC and alkaline methylamine methods for a range of milk matrices. The FIA method consistently gives the lowest standard deviations and coefficient of variation for the various milk matrices analyzed.

Enzyme microgels in packed-bed bioreactors with downstream amperometric detection using microfabricated interdigitated microsensor electrode arrays.

In this article, we describe the use of pH- responsive hydrogels as matrices for the immobilization of two enzymes, glucose oxidase (GOx) and glutamate oxidase (GlutOx). Spherical hydrogel beads were prepared by inverse suspension polymerization and the enzymes were immobilized by either physical entrapment or covalent immobilization within or on the hydrogel surface. Packed-bed bioreactors were prepared containing the bioactive hydrogels and these incorporated into flow injection (FI) systems for the quantitation of glucose and monosodium glutamate (MSG) respectively. The FI amperometric detector comprised a microfabricated interdigitated array within a thin-layer flow cell. For the FI manifold incorporating immobilized GOx, glucose response curves were found to be linear over the concentration range 1.8-280 mg dL(-1) (0.1-15.5 mM) with a detection limit of 1.4 mg dL(-1) (0.08 mM). Up to 20 samples can be manually analyzed per hour, with the hydrogel-GOx bioreactor exhibiting good within-day (0.19%) precision. The optimized FI manifold for MSG quantitation yielded a linear response range of up to 135 mg dL(-1) (8 mM) with a detection limit of 3.38 mg dL(-1) (0.2 mM) and a throughput of 30 samples h(-1). Analysis of commercially produced soup samples gave a within-day precision of 3.6%. Bioreactors containing these two physically entrapped enzymes retained > 60% of their initial activities after a storage period of up to 1 year.

Urinary fluoride levels in children in a single school in Trinidad and Tobago: a preliminary investigation

OBJECTIVE: To determine urinary fluoride levels in school children in a non-fluoridated area in Trinidad and Tobago. METHOD: Morning urine samples were requested from 750 children aged 5 to 14 years, attending a primary school in the area of St Joseph, north west Trinidad. Urine was collected at home and brought to school in labelled plastic bottles. Urinary fluoride concentration (ppm) was measured using an ion-specific electrode. RESULTS: Urine samples were available for 500 children (67). Mean age was 8.5 years. Overall mean fluoride concentration was 0.5 ppm +/- standard deviation (SD) 0.27; males (n = 263) were 0.58 ppm +/- 0.28 and females (n = 237) 0.55 ppm +/- 0.27. Children in the 5 to 7-year age group had the highest levels (0.64 ppm +/- 0.33). CONCLUSION: Mean urinary fluoride levels in this sample of school children were low indicating a fluoride intake below the optimum level for caries prevention. Fluoridation programmes may need to be implemented to increase fluoride intake among school children in the study area.

Ataxia Telangiectasia. A case report

The case of an eight year old girl with Ataxia Telangiectasia (AT) is described. She presented at seven years of age with gait problems and was found to have the neurological, dermatological and immunological features characteristic of AT along with a history of frequent sino-pulmonary infections. This report highlights the refractory nature of the disease, the difficulties in medical management, and the problems posed by late diagnosis which can compromise patient care. This is a rare inherited form of ataxia which has not been previously reported in West Indian literature.

Ataxia Telangiectasia: A case report

The case of an eight year old girl with Ataxia Telangiectasia (AT) is described. She presented at seven years of age with gait problems and was found to have the neurological, dermatological and immunological features characteristic of AT along with a history of frequent sino-pulmonary infections. This report highlights the refractory nature of the disease, the difficulties in medical management, and the problems posed by late diagnosis which can comprise patient care. This is a rare inherited form of ataxia which has not been previously reported in West Indian literature. (AU)

Dengue in Trinidad: a survey of knowledge, attitudes, practices and beliefs in two communities in Trinidad, West Indies

This study was conducted to test the Health Belief Model as it relates to dengue fever in two urban communities, namely Curepe and Woodbrook, Trinidad using a knowledge, attitude, practices and beliefs questionnaire and entomological investigations. The knowledge of dengue symptomatology, its prevention and control suggested a high level of awareness about dengue and its aetiological agents among residents of both commuities, but the connection between the vector Aedes aegypti (L.) and dengue fever transmission was poorly understood. The major determinants for cues to action were demographics, prevention of water treatment and garbage collection and disposal. Data from the present study gave clear indications of the need for health education programs, defining what garbage is and the further studies using the transtheoretical model of change (Prochaska Model). With these tools a holistic approach to vector control using community participation, health education and conventional vector control strategies may be adopted for the prevention and control of dengue and its vector. Ae. aegypti, on a sustained basis in Trinidad and, possibly, the Caribbean region.(AU)