Prevalence and socioeconomic determinants of dental sealant use among schoolchildren in Saudi Arabia.

There are no published research reports on the prevalence of dental sealant use in children in Saudi Arabia. This study determined the prevalence and socioeconomic indicators of dental sealant use on the permanent molars of a stratified random sample of schoolchildren in Jeddah. A basic oral screening survey of students was conducted by dentists and a self-administered questionnaire was completed by parents. The prevalence of dental sealant use among 1668 3rd and 8th grade students was 9.0%. Students who attended public schools and those who had fathers with lowerthan high-school education were less likely to have sealants. A stepwise logistic regression model showed that socioeconomic status of school district, family's monthly income, family's type of home, having medical insurance and receiving government financial support were significantly associated with sealant use. Efforts to increase sealant use and to reduce socioeconomic disparities appear warranted in the light of high rates of dental disease.

Prevalence and socioeconomic determinants of dental sealant use among schoolchildren in Saudi Arabia

There are no published research reports on the prevalence of dental sealant use in children in Saudi Arabia. This study determined the prevalence and socioeconomic indicators of dental sealant use on the permanent molars of a stratified random sample of schoolchildren in Jeddah. A basic oral screening survey of students was conducted by dentists and a self-administered questionnaire was completed by parents. The prevalence of dental sealant use among 1668 3rd and 8th grade students was 9.0%. Students who attended public schools and those who had fathers with lower than high-school education were less likely to have sealants. A stepwise logistic regression model showed that socioeconomic status of school district, family's monthly income, family's type of home, having medical insurance and receiving government financial support were significantly associated with sealant use. Efforts to increase sealant use and to reduce socioeconomic disparities appear warranted in the light of high rates of dental disease

Invasive meningococcal disease in adolescents and young adults.

CONTEXT: Incidence of invasive meningococcal disease has increased recently in persons aged 15 through 24 years. OBJECTIVE: To characterize meningococcal infection in adolescents and young adults in Maryland during the 1990s. DESIGN AND SETTING: Population-based surveillance study for meningococcal disease from January 1, 1990, through December 31, 1999, in Maryland. PATIENTS: Maryland residents diagnosed as having invasive meningococcal disease. MAIN OUTCOME MEASURE: Invasive meningococcal infection. RESULTS: Of 295 total cases, 71 (24.1%) occurred among persons aged 15 through 24 years. Sixteen (22.5%) of these cases were fatal. The annual incidence rate increased from 0.9 to 2.1 cases per 100 000 among 15 through 24 year olds (P =.01). The proportion of all disease increased from 16.0% to 28.9% (P =.03). The incidence and proportion of cases subsequently decreased to 1.0 and 16.4% in 1998 through 1999, respectively. Infection in 15 through 24 year olds was more likely to be fatal than infection in those younger than age 15 years (22.5% vs 4.6%; P =.001). Infection in 15 through 24 year olds, compared with those aged 25 years or older, was more likely to be associated with male sex (66.2% vs 34.8%; P<.001) and serogroup C infection (46.9% vs 20.2%; P<.001), respectively. Infections were potentially preventable with the licensed meningococcal vaccine in 82.8% of 15 through 24 year olds, 68.1% of those younger than 15 years, and 76.8% of adults aged 25 years or older. CONCLUSIONS: Incidence of meningococcal infection in 15 through 24 year olds in Maryland increased and then declined during the 1990s. Infection in this age group was associated with an unusually high case-fatality ratio, and the vast majority of cases were potentially vaccine preventable.

Pharmacokinetics and metabolic effects of triamcinolone acetonide and their possible relationships to glucocorticoid-induced laminitis in horses.

Experiments were performed to establish the pharmacokinetics of triamcinolone acetonide and the effects of the glucocorticoid on glucose metabolism in horses. The pharmacokinetics after intravenous (i.v.) dosing was best described by a three-compartment open model. There was rapid distribution from the central compartment followed by two phases of elimination. The half-life of the rapid elimination phase was 83.5 min and of the slower phase was 12 h. The term (Vss/Vc)-1was 12.3 indicating extensive distribution into the tissues. Triamcinolone acetonide given i.v. or intramuscularly (i.m. ) induced a prolonged period of hyperglycaemia, hyperinsulinaemia and hypertriglyceridaemia. Significant changes in plasma glucagon and serum non-esterified fatty acids were not observed. These observations suggest that the hyperglycaemia was a result of decreased glucose utilization by tissues and increased gluconeogenesis. The effects on glucose metabolism persisted for 3-4 days after triamcinolone was given i.m. at 0.05 mg/kg, the upper limit of the recommended dose range, and for 8 days when given at 0. 2 mg/kg. These observations, together with recent evidence implicating inhibition of glucose metabolism in the pathogenesis of equine laminitis, indicated that triamcinolone-induced laminitis may be associated with the long duration of action of the glucocorticoid when higher than recommended doses or when repeated doses are given.

Multiplex PCRs for identification of Escherichia coli virulence genes.

PCRs were developed to detect 11 Escherichia coli virulence genes. Primers amplified the respective genes without cross-reaction with other genes. Specificity was maintained in multiplex reactions; excellent amplification of target genes was possible with a minimum of four multiplex reactions. These reactions successfully identified genes in E. coli from the feces of four dogs.

Analysis of the amino acid indospicine in biological samples by high performance liquid chromatography.

Indospicine is a hepatotoxic amino acid that accumulates in the meat of horses that consume the legume Indigofera linnaei. A method to determine indospicine concentration in biological samples using an amino acid analyser has been reported, but the analysis time is long and therefore not suited to the analysis of large numbers of samples. A rapid and reliable method was developed for the analysis of indospicine in horsemeat and serum using High Performance Liquid Chromatography. Horsemeat and serum were extracted with either water or 0.01 N hydrochloric acid, respectively, and deproteinized by ultrafiltration. Precolumn derivatization of samples with phenylisothiocyanate was followed by separation of indospicine from other amino acids on a Pico-Tag C 18 column and UV detection at 254 nm. The calibration curves for indospicine in horsemeat extract were linear over the concentration range 0.4 microg ml(-1) to 20 microg ml(-1), while for indospicine in serum, the linear range was from 0.17 microg ml(-1) to 16.67 microg ml(-1). The mean recovery of indospicine in horsemeat extract was 87.2 +/- 6.8% and in serum was 97.3 +/- 9.9%. Analysis time for indospicine in horsemeat samples was 31 min and in serum samples was 36 min.

Cerebrospinal angiostrongyliasis in five captive tamarins (Sanguinus spp).

Four cotton-top tamarins (Sanguinus oedipus oedipus) and one emperor tamarin (S imperator subgrisescens) housed in a zoo became depressed, anorexic, paraparetic and eventually paralysed. The animals died within 5 days to 18 months of the appearance of clinical signs. Histological examination showed nonsuppurative and eosinophilic meningoencephalitis, and metastrongyle nematode larvae were found within subarachnoid spaces of all animals and within the spinal cord of one. Intact larvae with features consistent with Angiostrongylus cantonensis were recovered from the brain of one animal. This parasite is the classical cause of eosinophilic meningoencephalitis in many parts of the world and the diagnosis can be strongly suspected on clinical grounds. In endemic areas like south-east Queensland, protection of captive animals against infection with A cantonensis is a difficult balance between providing a stimulating, natural setting and eliminating potentially infectious definitive, intermediate and paratenic hosts. This is the first report of cerebrospinal angiostrongyliasis in tamarins and nonhuman primates in Australia.

Batimastat (BB-94) inhibits matrix metalloproteinases of equine laminitis.

A method for culturing explants of lamellar hoof was developed to investigate the process of lamellar separation that occurs in laminitis. Explants, consisting of hoof wall, dermal and epidermal lamellae and the adjacent sub-lamellar connective tissue remained intact when cultured in tissue culture medium for 2 days. However, when cultured in the presence of the matrix metalloproteinase (MMP) activator aminophenylmercuric acetate (APMA), the lamellae separated when tension was applied by pulling the hoof wall in an opposite direction to the connective tissue. The separation occurred between the epidermal basal cells and the basement membrane therefore mimicking the lesion of laminitis. Electrophoresis of culture medium from control hoof explants into gradient polyacrylamide gels co-polymerised with gelatin revealed that the explants had produced 2 gelatinases of molecular weight 92 and 72 kDa corresponding to EqMMP-9 and EqMMP-2 respectively. Minor bands of lower molecular weight were the active forms of these enzymes. The zymograms of culture medium from APMA treated explants revealed an increase in the amount of active MMPs. Equine polymorphs cultured for 2 days produced only EqMMP-9. Lamellar explant medium from horses with acute laminitis contained increased amounts of zymogen and active EqMMP-2 and EqMMP-9 particularly in explants from the fore hooves. Zymography of homogenates of normal lamellar hoof tissue revealed only EqMMP-2 and a minor active band. However, homogenates of lamellar tissue from horses with laminitis showed that EqMMP-9 was present as well as increased EqMMP-2 in both zymogen and active forms. Addition of the MMP inhibitor batimastat (BB-94) to the culture medium of APMA treated explants prevented lamellar separation. BB-94 incubated with polyacrylamide strips containing the MMPs from laminitis affected lamellar explants inhibited enzymatic activity at a concentration of 1 mmol/l. It is concluded that activation of MMPs may be responsible for the lamellar separation seen in laminitis and that MMP inhibitors may be useful clinically for preventing this process.

Decreased glucose metabolism causes separation of hoof lamellae in vitro: a trigger for laminitis?

Explants of horses' hooves remained intact for up to 8 days when incubated in Dulbecco's modified Eagle medium (D-MEM) containing 25 mmol/l glucose but separated within 36 h when incubated in saline. The separation occurred between the basal epidermal cells and their basement membrane which is characteristic of the hoof separation that occurs in laminitis. Separation of hoof explants was prevented by addition of glucose to saline and was induced by adding 2-deoxyglucose or aminophenylmercuric acetate to D-MEM. Glucose consumption by the hoof explants was inhibited by 2-deoxyglucose and aminophenylmercuric acetate. The explants consumed relatively large amounts of glucose during the first 2 days of incubation and then little over the next 6 days. Despite the reduced glucose consumption, the hoof explants did not separate over 8 days of incubation. The results indicated that the integrity of the hoof explants was initially dependent on consumption of glucose and provide a possible explanation for the development of laminitis caused by conditions such as carbohydrate overload, acute inflammatory conditions, corticosteroid therapy and hyperlipidaemia. It would be expected that these conditions would induce a major hormonally-mediated metabolic shift away from glucose consumption by many peripheral tissues. It is suggested, therefore, that if the metabolic change occurred faster than the hoof tissue could adapt to an alternative energy substrate, then hoof separation and laminitis would occur.

Inhibitory effects of short intravascular infusions of propionate on reticulo-rumen motility in the sheep.

The effect of short infusions into the hepatic portal vein of propionate on reticulo-rumen motility was examined in conscious sheep. Infusions of 10 min duration of propionate at 1-6 mmol.min-1 into the portal vein reduced the frequency and amplitude of reticulum and rumen contractions, especially the amplitude of rumen contractions. Inhibitory effects were not confined to the portal route and were also obtained via the jugular vein, carotid artery, coeliac artery and anterior mesenteric artery. Butyrate was also effective, but acetate much less so and NaCl almost without effect. The inhibitory responses remained after section of nerves to the liver. It appears unlikely the effects reflexly originate from the liver or are derived centrally.

Collaborative needs assessment and systems development in Alabama: Process and products.

This article describes the implementation of a collaborative project and its results, involving a department of maternal and child health (DMCH) in a school of public health and a state department of public health. The state received a federal grant to enhance systems development for women and children. Adequate information regarding the existing system of health care was lacking. The state contracted with the DMCH for assistance in designing and conducting a needs assessment, whose purpose was to (1) identify strengths and weaknesses in the state system of care, (2) provide baseline information for targeting resources and measuring change, and (3) initiate an on-going process of assessment and evaluation of need. The DMCH collected data about financial and nonfinancial barriers to care from state-level health agency and organization experts, county-level service personnel, and consumers. The contributions to understanding the needs of the state offered by the information garnered in the three surveys helped the state in setting immediate and long-range objectives. The presence of the school of public health and the focus of its particular DMCH on assisting state agencies provided an atmosphere in which the state could ask for assistance and the university could respond in a way that was useful and relevant to the state's needs. Medical Subject Headings (MeSH): assessment, health planning, health priorities, interprofessional relations, program planning, public health.

Effects of the naturally occurring arginine analogues indospicine and canavanine on nitric oxide mediated functions in aortic endothelium and peritoneal macrophages.

The ability of the naturally occurring non-protein toxic amino acids indospicine and canavanine to inhibit nitric oxide synthesis was tested in isolated rat aorta and cultured rat peritoneal macrophages. Both compounds inhibited acetylcholine induced relaxation of rat aorta contracted with noradrenaline, a process mediated by nitric oxide generated in vascular endothelium. Nitric oxide is generated in vascular endothelium from arginine by a constitutive nitric oxide synthase. Indospicine and canavanine also increased superoxide mediated reduction of cytochrome c by phorbol myristate acetate stimulated rat peritoneal macrophages. The increase in superoxide under these conditions was due to decreased nitric oxide synthesis. Macrophage synthesis of nitric oxide is mediated by an inducible form of nitric oxide synthase. It is concluded that indospicine and canavanine are inhibitors of constitutive and inducible nitric oxide synthases and it is suggested that the toxicity associated with these compounds could be related to this activity.

Pharmacokinetics and metabolism of amitraz in ponies and sheep.

Amitraz and its active metabolite BTS27271 were given intravenously to ponies and sheep at equimolar doses of 1 mg/kg and 0.68 mg/kg, respectively, and the plasma concentrations of amitraz and BTS27271 estimated at various times thereafter. Amitraz was hydrolysed to BTS27271 in both species. Amitraz was undetectable in sheep plasma after approximately 5 min but persisted in the plasma of ponies for at least 90 min. The persistence of unmetabolized amitraz in ponies may have implications for the toxicity of amitraz in that species. The primary and secondary disposition half-lives of amitraz in ponies were 2 and 39 min, respectively. BTS27271 was distributed rapidly outside the plasma in both species with a primary disposition half-life of 4.4 min in sheep and 5.9 min in ponies. The secondary disposition half-lives were 51 and 55 min, respectively. The secondary phase of the disposition of BTS27271 was similar whether BTS27271 was given directly or derived by hydrolysis from amitraz. However, significant differences were evident in the primary phase of the disposition of BTS27271. Sheep demonstrated a larger apparent volume of distribution of BTS27271 than ponies and more rapid body clearance.

3-Nitropropionic acid toxicity in cultured murine embryonal carcinoma cells.

The morphologic and histochemical effects of 3-nitropropionic acid (NPA) were examined in cultured murine embryonal carcinoma cells. NPA caused a dose-dependent inhibition of cell proliferation of cultured murine embryonal carcinoma cells at concentrations above 1.05 mM and was lethal at 4.2 mM. Morphologic changes included gross swelling of the cells, swelling of mitochondria and accumulation of organellar debris within the cytoplasm. NPA inhibited the activity of succinate dehydrogenase but not of malate, isocitrate or glucose-6-phosphate dehydrogenases, resulting in a decrease in intracellular ATP. Although succinate dehydrogenase activity was decreased by NPA, propionic acid and its mercapto-, 2-chloro-, and 3-chloro- derivates did not affect enzyme activity. 3-Nitropropanol also inhibited succinate dehydrogenase but only at a much higher concentration than was required with NPA. The results provide evidence that cytotoxicity caused by NPA results from inhibition of succinate dehydrogenase activity leading to depression of ATP synthesis. Loss of cellular integrity is probably a direct consequence of failure of energy-dependent cell homeostatic mechanisms such as the plasma membrane Na+/K+ pump, resulting in swelling and ultimately lysis of the cell.

Pharmacokinetics and absolute bioavailability of cyclosporin following intravenous and abomasal administration to sheep.

Cyclosporin A pharmacokinetics were studied following intravenous and abomasal dosing in an open, crossover study in healthy, merino ewes. Five different doses of cyclosporin A were dispersed in milk and administered into the abomasum through a surgically inserted fistula which simulates oral administration. Cyclosporin A was well tolerated. Whole blood concentrations of cyclosporin A were measured by HPLC and mean clearance (0.45 +/- 0.05 L h-1 kg-1), distribution volume (4.4 +/- 2.0 L kg-1), mean residence time (9.6 +/- 4.1 h) and half-life (12.1 +/- 3.1 h) were calculated cyclosporin A was excreted in urine or bile. Area under the curve increased proportionally with doses up to 26.3 mg kg-1, but was curvilinear above this dose. Abomasal bioavailability at 6.4 mg kg-1 was 0.26 +/- 0.09, and mean absorption time was 4.7 +/- 11.1 h. Considerable pharmacokinetic variability was observed, particularly after abomasal administration. Cyclosporin A pharmacokinetics in sheep lie within the values reported in man after renal, bone marrow and cardiac transplantation.

Chlamydial infection and sexual behavior in young pregnant teenagers.

Chlamydia trachomatis infection is one of the most common sexually transmitted diseases (STD) among adolescents and is one of the most common causes of perinatal infection. We have screened 267 young nulliparous adolescent girls (12-17 years old) for cervical C. trachomatis infection during their pregnancy using tissue culture methods. The population was a cohort of pregnant teenagers who had limited sexual exposure (mean duration of sexual activity, 14.3 months, mean number of lifetime partners, 2.0 +/- 1.5). The initial screening was done at enrollment to a prenatal care clinic, and the third trimester examination at 32 to 36 weeks of gestation. According to clinical indications, additional interim STD examinations were carried out. The cervical C. trachomatis infection rate was 18.7% (50/267) at intake and 7.9% (14/178) in the third trimester. Three of the 40 interim STD examinations also were positive for cervical C. trachomatis infection. Prenatally, 64 of 267 (24.0%) girls were positive for C. trachomatis at one or more times. The repeat culture positive rate for C. trachomatis was 7.8% (17/218), and 14 of those that were negative on the initial screening were positive on the subsequent screening. One or more types of treatable STDs (chlamydial, gonorrhea, syphilis, or trichomonal) were identified in 38.6% (103/267) of the study population during pregnancy. These findings suggest that high-risk sexual behavior may continue in teen pregnancy, and repeated prenatal chlamydial and other STD screening and counseling are indicated in this population.

Comparative pharmacokinetics of amoxicillin administered intravenously to sheep and goats.

The pharmacokinetic behavior of sodium amoxicillin was studied after intravenous administration to six sheep and five goats to determine if there are species differences in disposition. The plasma drug concentrations vs. time following intravenous administration of 10 mg/kg were best described by the biexponential equations Cp = 42.9e-0.077.t + 3.68e-0.0134.t for goats, and Cp = 53.5e-0.06.t + 1.69e-0.015.t for sheep. The terminal disposition half-lives for sheep and goats were 46.3 and 66.9 min respectively and were not significantly different. Amoxicillin clearance for sheep and goats were 10.1 and 11.4 ml/min.kg respectively. There were no significant differences between any of the pharmacokinetic parameters measured in sheep and goats.

Effect of amitraz and its metabolites on intestinal motility.

1. Amitraz was rapidly metabolised to BTS27271 after intravenous administration to sheep. 2. Amitraz and BTS27271 had significant H1-histamine antagonist activity on isolated guinea-pig ileum. BTS27271 was approximately 3.3 times as potent as amitraz. 3. Intravenous injection of amitraz and its metabolite BTS27271 caused an immediate cessation of caecal motility in sheep, which persisted for 74-245 min. 4. Caecal stasis induced by amitraz was reversed by yohimbine but only partially reversed by 2-pyridylethylamine. 5. The results suggest that despite the significant antihistamine activity of amitraz and BTS27271 in vitro, it is probably the alpha-2-adrenergic agonist activity that is the most important in causing large intestinal stasis in vivo.