Coastline Kriging: A Bayesian Approach

Statistical interpolation of chemical concentrations at new locations is an important step in assessing a worker's exposure level. When measurements are available from coastlines, as is the case in coastal clean-up operations in oil spills, one may need a mechanism to carry out spatial interpolation at new locations along the coast. In this paper we present a simple model for analyzing spatial data that is observed over a coastline. We demonstrate four different models using two different representations of the coast using curves. The four models were demonstrated on simulated data and one of them was also demonstrated on a dataset from the GuLF STUDY. Our contribution here is to offer practicing hygienists and exposure assessors with a simple and easy method to implement Bayesian hierarchical models for analyzing and interpolating coastal chemical concentrations

Disposition of uric acid upon administration of ofloxacin alone and in combination with other anti-tuberculosis drugs

Disposition of uric acid upon administration of ofloxacin (O) alone and in combination with other anti-tuberculosis drugs, rifampicin (R), isoniazid (H) and pyrazinamide (Z) was studied. Twelve male healthy volunteers were investigated on four different occasions with the four drugs alone or in combinations. A partially balanced incomplete block design was adopted and the subjects were randomly allocated to each group. Uric acid concentration in urine samples excreted over 0-8 hr, were determined after coding the samples. There was significant decrease in the group receiving Z when compared to other groups. Though there was a decrease in uric acid excretion in the group receiving O, it was not statistically significant. Rifampicin and H seem to increase the uric acid excretion. The incidence of arthralgia was mainly due to Z and not due to either O or other drugs in the treatment of pulmonary tuberculosis

Ofloxacin pharmacokinetics in saliva

Objective: To study the pharmacokinetics of ofloxacin using salivary drug concentration when administered alone or in combination with rifampicin (R), isoniazid (H) and pyrazinamide (Z) and also to assess the saliva to plasma concentration ratio. Material and Methods: Twelve healthy male volunteers were investigated on four different occasions with an interval of at least one week between occasions. They were administered ofloxacin, either alone or in combination with R, H and Z. A partially balanced incomplete block design was adopted and the subjects were randomly allocated to each group. Salivary and plasma concentrations of ofloxacin were measured at 1, 2, 3, 6 and 8 h after drug(s) administration using validated methods. Results: There were no significant differences between various pharmacokinetic parameters when ofloxacin was administered alone or in combination with R, H and Z. The mean saliva to plasma ratio of ofloxacin concentration was around 0.6. The bioavailability indices of ofloxacin in the saliva and plasma were similar in all the groups. Conclusion: Several pharmacokinetic parameters could be calculated using salivary concentrations of ofloxacin. The determination of ofloxacin levels in saliva may be useful in therapeutic drug monitoring and pharmacokinetic studies

Dose related pharmacokinetics of ofloxacin in healthy volunteers

OBJECTIVE: To evaluate the pharmacokinetic profile of ofloxacin in healthy volunteers after single oral doses of 600 and 800 mg. DESIGN: Seven healthy volunteers were administered 600 and 800 mg of ofloxacin on two occasions with an interval of one week. Paired samples of blood and saliva were collected after 1, 2, 3, 6, 9, 12, 24, 32 and 48 hours post-dose. Urine samples were collected over a period of 0–6, 6–12 and 12–24 hours. Concentrations of ofloxacin in plasma, saliva and urine were assayed by high performance liquid chromatography. RESULTS: Increases of 22% in peak plasma concentration (Cmax) and 40% in area under the concentrationtime curve (AUC0–24) were observed with the 800 mg dose. The other parameters, namely time to attain Cmax, half-life, the apparent volume of distribution, plasma and renal clearance and percentage of dose excreted in urine over 24 hours were independent of doses. The mean ratios of the concentration in saliva to the concentration in plasma ranged from 0.4–0.6, and the correlation coefficient was 0.94. CONCLUSIONS: Dose proportionality was observed in Cmax and AUC0–24 when 600 and 800 mg doses of ofloxacin were given. Ofloxacin determined in saliva seems to be suitable for therapeutic drug monitoring

Assay of ethambutol in pharmaceutical preparations

Ethambutol tablets of 200 and 400 mg denominations were assayed by the standard non-aqueous titration method and a simpler calorimetric method. With the titrimetric method, assay values, appreciably higher than the stated content (117% or more), were obtained with the products of 4 companies, while all the values were within 6% of the stated content by the calorimetric method. Rifampicin and pyrazinamide interfered with the estimation of ethambutol by both methods: isoniazid, however, caused an overestimation with the titrimetric method only

Pregnancy associated plasma protein-A (PAPP-A) as an early marker for the diagnosis of acute coronary syndrome.

Aims and objectives Pregnancy associated plasma protein-A (PAPP-A), a metalloproteinase plays a pivotal role in the pathogenesis of atherosclerosis. Recent studies have reported that elevated levels of PAPP-A, signal the onset of acute coronary syndrome (ACS). We, therefore, proposed to study the analytical competence of PAPP-A in patients admitted to the emergency department with chest pain and finally diagnosed as ACS. Methods and results Pregnancy associated plasma protein-A was measured using enzyme-linked immunosorbent assay (ELISA) in 485 patients admitted to emergency care unit, of which 89 patients were diagnosed as Non-cardiac chest pain (NCCP). Elevated levels of PAPP-A were observed in patients diagnosed as ACS on comparison with the controls. Receiver operator characteristic (ROC) curve analysis showed PAPP-A to be a good discriminator between ischaemic and non-ischaemic patients. The area under the curve was found to be 0.904, 95% CI (0.874–0.929) with 90% sensitivity and 85% specificity (P< 0.0001). The cut-off value from the ROC curve was 0.55 μg/mL above which PAPP-A was considered to be positive. Conclusion Pregnancy associated plasma protein-A seems to be a promising biomarker for identification and risk stratification for patients with ACS

The Pharmacokinetics of ofloxacin, rifampicin, isoniazid and pyrazinmide when administered alone and in combination

The present study assesses the bioavailability of Ofloxacin (O) following single oral administration of the drug along with Rifampicin (R), or Isoniazid (H), or Pyrazinamide (Z) or a combination of three drugs. Information on the pharmacokinetics of O in the presence of R, H and Z based on the blood concentrations upto 8 hours, on the proportions of the doses of the drugs and their metabolites excreted in urine upto 8 hours and also the effect of O on the other antituberculosis (TB) drugs in terms of absorption and interactions are extensively studied. The bioavailability indices of these drugs are assessed. The investigation was undertaken in a total of 12 male healthy volunteers and each volunteer was investigated on four different occasions at weekly intervals. A partially balanced incomplete block design was employed and the allocation of O or the drug combinations was at random. Plasma concentrations of O, R, H and Z were determined. Urinary excretion of these drugs, together with their primary metabolites was also determined. Various pharmacokinetic parameters were calculated. The results have shown that the bioavailability of O is not impaired when administered with other antituberculosis drugs like R, H and Z and does not exercise any therapeutic penalty. The bioavailability of other anti-TB drugs like R, H and Z does not get affected when administered along with O. Human bioavailability studies, in general, provide direct straightforward information on the degree of absorption and biotransformation of drugs. The results of the present study indicate that the pharmacokinetic properties of O, R, H and Z as assessed after individual and combined administration of these drugs do not get affected or altered. Since there are no interactions among these drugs, the use of 0 in the treatment of pulmonary tuberculosis is justified