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PubMed1994

Sample preparation technique for iodine determination in urine and water samples.

A simple method for iodine determination in urine and water samples is presented. After digestion of the sample with chromic acid, the iodate produced was converted to iodide by the addition of a strong solution of sodium sulphite. The iodide was then precipitated as palladium iodide using a solution of palladium chloride. The precipitate was filtered through membrane filter paper, air-dried and analyzed using the Energy Dispersive X-Ray Fluorescence (EDXRF) method.

Humans↗
PubMedDate not supplied

[Presence of Toxocara spp eggs in public squares of Uberlandia city, Minas Gerais, Brazil].

The objective of this study was to verify the presence of Toxocara spp eggs in the public squares ground in Uberlândia, region of Triângulo Mineiro, from October 1991 to January 1992. The city has 89 squares distributed in 39 boroughs. In order to have an outline of the parasite's occurrence, ground and sand (when existent) samples were collected from one square per boroughors. The squares were determined by draw. The homogenized ground samples of distinct points of the 39 squares, were collected in plastic flasks and analysed by the methods of fluctuation in sodium chloride saturated solution and magnesium sulphate saturated solution which contained 5% of potassium iodate. Both methods were executed twice for each sample. The results showed that the ground of 9 squares (23.07%) was contaminated, 6 of which were located near downtown. The execution of more than one laboratorial method permitted the agent's identification in a greater percentage of squares.

Animals↗
PubMed1993

[Thyroid nodule disease in a previously endemic goiter area].

We conducted a 6-year study of 110 patients with thyroid nodular disease in a previously goitrogenic area. The aim of the present work was to establish its incidence, to determine if multinodular goiter and autonomous thyroid nodule have the same analytical and clinical behaviour and to verify if the iodation campaign had resulted in the development of thyrotoxicosis induced by iodine. The results demonstrated an incidence of 0.4 per 1,000 population and per year. The two modalities of thyroid nodular disease did not present any clinical and analytical differences. 58.2% of the patients had hyperthyroidism, 53.1% of which were T-4 thyrotoxicosis, 12.5% T-3 thyrotoxicosis and 34.4%, subclinical hyperthyroidism. 8.2% of the patients under study had hyperthyroidism induced by iodine (Jod Basedow), with iodide excretion values higher that 3 standard deviations with respect to the population average (> 220 micrograms/g creatinine).

Adult↗
PubMed1994

[Dynamic single-slice computed tomography in the pretreatment evaluation of hepatocarcinoma in cirrhosis].

Hepatocellular carcinomas (HCCs) are currently treated with surgery, transcatheter chemoembolization and percutaneous alcoholization; all methods require accurate in vivo anatomopathology of the lesion. The authors report their personal experience with 58 HCCs on cirrhosis which were studied with dynamic single-slice CT after the injection of water-soluble iodate contrast medium with automatic injector in a peripheral vein. Three semiologic patterns were identified according to lesion density on pre- and post-contrast images. The active portion of the lesion could be differentiated from the necrotic one in 100% of cases. Moreover, the necrotic lesion was differentiated from possible still viable tumor portions but with vacuolar degeneration phenomena. These findings allowed the authors to calculate the growth rate and the infiltrative capability of the single neoplastic masses. Finally, the dynamic evaluation of parenchymal enhancement allowed abnormal tissue vascularization due to arterioportal communication to be demonstrated in 7 cases. The authors conclude the dynamic single-slice CT allows the accurate assessment of HCC foci, of tumor tissue vascularization and of perilesional liver parenchyma. Therefore, dynamic single-slice CT is suggested as the technique of choice to study small HCCs before treatment.

Adult↗
PubMedDate not supplied

[The evaluation of a digital system for the automatic analysis of the density of abdominal radiograms].

This paper reports the results of the evaluation of an automatic system developed to analyze radiographic densities. This system, called RADEN, has been implemented at the Institute for Information Processing of the Italian National Research Council in Pisa. Forty-three pairs of abdominal X-ray films were obtained before and after the administration of ionic iodate contrast medium (i.i.c.m.) during urographic examinations. The 86 X-ray films were acquired and digitized using a computer-controlled optoelectronic device with a sampling step ranging 125 microns to 250 microns. The resulting images were arrays of 512 x 512 pixels, each one quantified on a byte (256 gray levels). The computing system included a high-performance personal computer equipped with a video RAM board having built-in facilities for image processing and with an optical disk to archive the images. Automatic and semi-automatic procedures were developed to segment, recognize and classify the images and to characterize three homogeneous regions--i.e., bone, water and air. The output data were compared with the area values of the air densities computed directly on the X-ray films by a radiologist. Furthermore, both data sets were compared with the scores given in a blind study by four observers. The subsequent statistic analysis showed the increase in air density areas after i.i.c.m. administration and the applicability of the implemented system to the automatic examination of abdominal radiographic densities. The results encourage to believe that the proposed approach could be employed as a first step for the development of quite a more complex system oriented to X-ray image understanding and to assisted diagnosis.

Contrast Media↗
PubMed1996

[Relationship between properties of 131I therapy and radioiodine kinetics].

AIM: The reason of unreproducible data under diagnosis and therapy with radioiodine should be elucidated. METHODS: The iodine content of the capsules was tested by a colorimetric method and by activation analysis. Radiochemical purity was determined by HPLC and by electrophoresis. Solubility of the capsules was investigated under different conditions. RESULTS: The iodine content of the capsules varied between 0.8 and appr. 100 micrograms/capsule. The radiochemical purity of the capsule iodine varied between 75% and 99.5% (main contamination: iodate). The solubility of the capsules differed. CONCLUSION: Additional non-radioactive iodine in the therapy capsules could be one reason of the reduced radioiodine-uptake under therapy.

Capsules↗
PubMed1996

[Computerized tomography of osteochondral diseases of the talus dome].

The definition "osteochondritis dissecans" of the talus improperly includes a variety of diseases involving the chondral surface of the talus dome and the relative subchondral bone. To investigate the CT diagnostic potentials in the study of these conditions, 35 patients complaining of a "painful ankle" were examined with plain radiography and axial and direct paracoronal CT over a 2-year period. Twelve patients were then examined with double contrast CT arthrography with air and iodated contrast agents. CT diagnostic accuracy was assessed evaluating the following parameters: the presence and extent of the subchondral bone fragment, the presence of residual bone fragment attachment at the lesion base or its intraarticular dislocation, the presence of subchondral bone cysts, of chondral surface lesions and, finally, of capsular and ligamentous damage. All the patients with CT findings of osteochondral conditions of the talus dome were submitted to arthroscopic examination/treatment and/or surgical arthrotomy. Baseline CT exams accurately depicted all the lesions, except for early (grade I) lesions. Moreover, the administration of intraarticular contrast agent (CT arthrography) increased the diagnostic accuracy in articular cartilage studies. Therefore, the authors believe baseline CT on the orthogonal planes to represent an effective tool for the staging of osteochondral talar lesions and for accurate treatment planning.

Adolescent↗
PubMedDate not supplied

Kinetic method for the assay of levodopa in pharmaceutical preparations.

A simple, rapid and accurate method for the analysis of levodopa using integral method, is described. The spectrophotometric measurements were recorded by measuring the increase in absorbance at 470 nm, when L-dopa was reacted with potassium iodate at room temperature. The kinetic parameters were calculated. The concentration range was valid from 60-700 ppm. The proposed kinetic method has been applied successfully to pharmaceutical preparations.

Kinetics↗
PubMed2004

Iodine supplementation for preventing iodine deficiency disorders in children.

BACKGROUND: Iodine deficiency is the main cause of potentially preventable mental retardation in childhood, as well as causing goitre and hypothyroidism in people of all ages. It is still prevalent in large parts of the world. OBJECTIVES: To assess the effects of iodine supplementation overall, and of different forms and dosages of iodine supplementation separately, in the prevention of iodine deficiency disorders in children. SEARCH STRATEGY: The Cochrane Library, MEDLINE, EMBASE and reference lists, databases of ongoing trials and the Internet were searched. Date of latest search: October 2003. SELECTION CRITERIA: We included randomised controlled trials and prospective controlled trials not using randomisation of iodine supplementation in children living in areas of iodine deficiency. DATA COLLECTION AND ANALYSIS: Two reviewers did the initial data selection and quality assessment of trials independently. As the studies identified were not sufficiently similar and not of sufficient quality, we did not do a meta-analysis but summarised the data in a narrative format. MAIN RESULTS: Twenty-six prospective controlled trials were related to our question, assessing a total of 29613 children. Twenty of them were classified as being of low quality, six of moderate quality. Most studies used iodised oil as a supplement, but other supplements were also used. The intervention groups were compared to a non-supplemented control group, different doses or different forms of iodine supplementation. There was a clear tendency towards goitre reduction with iodine supplementation; this was significant in several studies. Significant differences in physical development were not seen, except in one study. Results for differences in cognitive and psychomotor measures were mixed, with only few studies showing a positive intervention effect. One study suggested that infant mortality was lowered after iodine supplementation. Most studies showed a significant increase in urinary iodine excretion and levels recommended by the WHO were reached in most cases after supplementation. Thyroid-stimulating hormone (TSH) levels were significantly reduced in one study. In 1.8% of the children investigated, adverse effects were found, most of them were minor and transient. REVIEWERS' CONCLUSIONS: Despite most of the included studies being of low quality, the results suggest that iodine supplementation, especially iodised oil, is an effective means of decreasing goitre rates and improving iodine status in children. Indications of positive effects on physical and mental development and mortality were seen, although results were not always significant. Adverse effects were generally minor and transient. Insufficient evidence was available on non-oil supplements. High quality controlled studies investigating relevant long term outcome measures are needed to address the question of the best form of iodine supplementation in different population groups and settings.

Child↗
PubMed1998

Capillary electrophoresis of anions at high salt concentrations.

It is commonly thought that even a moderately high ionic concentration in the background electrolyte (BGE) would lead to Joule heating and serious peak distortion. However, we obtained very satisfactory separations of both inorganic and organic anions in electrolyte solutions as high as 5 M sodium chloride using direct photometric detection. Samples containing a 0.5 M concentration of a salt can be analyzed directly by making the BGE concentration of the same salt even higher to obtain electrostacking. The temperature in the center of the capillary was calculated to be 49 degrees C when the current is at its maximum of 280 microA. The effect of various salts on electrophoretic and electroosmotic mobility is discussed. Several examples are given of capillary electrophoresis under high-salt conditions.

Anions↗
PubMed1995

Müller cell involvement in methanol-induced retinal toxicity.

Methanol is an ocular toxicant which causes visual dysfunction often leading to blindness after acute exposure. The physiological and biochemical changes responsible for this toxicity are poorly understood. Previously, we reported that the folate-reduced (FR) rat is an animal model which mimics the characteristic human methanol toxicities. The present study examines the hypothesis that depletion of ATP after methanol administration is the initiating event in methanol-induced retinal toxicity. ATP is reduced in retinae of methanol-treated FR rats to the same extent as is seen in retinae of FR and folate-sufficient (FS) rats treated with the Müller cell (retinal glial cell) toxin alpha-aminoadipic acid. Changes in the electroretinogram and the response of Müller cells to a potassium stimulus are also similarly eliminated in methanol-treated FR rats and alpha-aminoadipic acid-treated FR and FS rats. These results suggest that the Müller cell may be the initial target in methanol-induced visual system toxicity.

2-Aminoadipic Acid↗
PubMed1984

Distinctly different rates of benzocaine action on sodium channels of Ranvier nodes kept open by chloramine-T and veratridine.

Single myelinated nerve fibres of the frog, Rana esculenta, were voltage clamped in a fast-exchange chamber in the presence of 10 mM TEA to block potassium channels. After treatment with 0.6 mM chloramine-T for 1-4 min a sizeable INa component persisted even during a 14-s depolarizing impulse. Changing the perfusate to Ringer solution + 1 mM benzocaine resulted in a fast reduction (half time ca. 0.06 s) of the persistent INa, comparable to the rate of block of peak INa during a series of short impulses before chloramine-T. In the presence of 60 microM veratridine the peak INa was followed by a slow exponential (tau s) reincrease of inward current, Is, that did not appreciably inactivate. Application of 0.25 mM benzocaine during a 14-s depolarizing impulse caused Is to decrease exponentially with a large time constant, tau on of 4.3 s. Recovery on washout proceeded with tau off = 3.4s. Tau on was little dependent on benzocaine concentration and was 4.5 s on the average in 1 mM. Tau on in 25 microM was insignificantly (15%) larger than in 1 mM if tested on the same fibre. After equilibration in 25 microM, 0.25 mM and 1 microM, Is(t = 14s) was reduced to 0.69, 0.30, and 0.10, respectively, of the value without anaesthetic. Cooling by only 4-5 degrees C reduced Is and much increased tau s. tau on (1 mM benzocaine) increased almost in proportion to tau s. Tail currents during a series of pulses (1.1 s every 2.5 s) were reduced by 0.25 mM benzocaine clearly faster (tau on = 1.3 s) than Is during a long pulse of the same amplitude.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Voltage-dependent effect of a scorpion toxin on sodium current inactivation.

In voltage clamped nodes of Ranvier inactivation of the sodium permeability is slowed by toxin V from the scorpion Centruroides sculpturatus, by sea anemone toxin ATX II or by internally applied KIO3. The slow decay of the Na inward current is markedly accelerated if the test pulse is preceded by a depolarizing conditioning pulse followed by a 10-500 ms pause. This phenomenon was studied in detail, using conditioning pulses of varying amplitude and up to 15 s duration. In nodes treated with toxin V a 20 ms conditioning pulse to positive potentials was sufficient to produce a clear acceleration of the decay of the Na current and a reduction of the inward current remaining at the end of a 50 ms test pulse, i.e. a weakening of the toxin effect. In nodes treated with ATX II or internal KIO3 longer conditioning pulses were required. A similar effect of conditioning pulses on the decaying phase of the Na current was also observed in untreated fibres. To study the phenomenon quantitatively we fitted the decaying phase of the inward Na current with the equation INa = A exp(-t/tau 1) + B exp(-t/tau 2) + C. The effect of depolarizing conditioning pulses could be described as an increase of A, a decrease of B and C and a reduction of the time constants tau 1 and tau 2. I50/Ipeak, the normalised inward current remaining at the end of a 50 ms test pulse, decreased exponentially with increasing duration of the conditioning pulse to a steady-state value. The time constant tau and the steady-state value depended on the potential during the conditioning pulse. For nodes treated with toxin V, tau was 0.24 s at 0 mV and 12 degrees C and half inhibition occurred at -42 mV. The time constant tau was larger for nodes treated with ATX II or internal KIO3. At positive potentials, I50 was reduced to 20% of the control value in toxin V-treated nodes, but only to 70% in KIO3-treated nodes. Recovery from the effect of the conditioning pulse was studied by varying the pause between conditioning pulse and test pulse; recovery was 66-100% complete after 500 ms. The results are interpreted by assuming that a depolarizing conditioning pulse (a) accelerates inactivation of the sodium permeability and (b) causes dissociation of the toxin-receptor complex or transition into an inactive state. The latter effect occurs in toxin V-treated fibres but not in those treated with ATX II or KIO3.

Animals↗