In Vivo and in Vitro Percutaneous Absorption and Skin Decontamination of Arsenic from Water and Soil

The objective was to determine the percutaneous absorption ofarsenic-73 as H₃A_sO₄ from water and soil. Soil (Yolo County65-California-57-8) was passed through 10-, 20-, and 48-meshsieves. Soil retained by 80 mesh was mixed with radioactivearsenic-73 at a low (trace) level of 0.0004 µg/cm² (microgramsarsenic per square centimeter skin surface area) and a higherdose of 0.6 µg/cm². Water solutions of arsenic-73 at alow (trace) level of 0.000024 µg/cm² and a higher doseof 2.1 µg/cm² were prepared for comparative analysis.In vivo in Rhesus monkey a total of 80.1 ± 6.7% (SD)intravenous arsenic-73 dose was recovered in urine over 7 days;the majority of the dose was excreted in the first day. Withtopical administration for 24 hr, absorption of the low dosefrom water was 6.4 ± 3.9% and 2.0 ± 1.2% fromthe high dose. In vitro percutaneous absorption of the low dosefrom water with human skin resulted in 24-hr receptor fluid(phosphate-buffered saline) accumulation of 0.93 ± 1.1%dose and skin concentration (after washing) of 0.98 ±0.96%. Combining receptor fluid accumulation and skin concentrationgave a combined amount of 1.9%, a value less than that in vivo(6.4%) in the Rhesus monkey. From soil, receptor fluid accumulationwas 0.43 ± 0.54% and skin concentration was 0.33 ±0.25%. Combining receptor fluid plus skin concentrations gavean absorption value of 0.8%, an amount less than that with invivo absorption (4.5%) in the Rhesus. These absorption valuesdid not match current EPA default assumptions. Washing withsoap and water readily removed residual skin surface arsenic,both in vitro and in vivo. The partition coefficient of arsenicin water to powdered human stratum corneum was 1.1 x 10⁴andfrom water to soil it was 2.5 x 10⁴. This relative similarityin arsenic binding to powdered human stratum corneum and soilmay indicate why arsenic absorption was similar from water andsoil. This powdered human stratum corneum partition coefficientmodel may provide a facile method for such predictions.     

Prevalence of dental fluorosis in children taking part in an oral health programme including fluoride tablet supplements from the age of 2 years

International Journal of Paediatric Dentistry 2010; 20: 347–352 Aim. To investigate the prevalence of dental fluorosis in children who had participated in an oral health programme between the ages 2–5 years, including fluoride tablets from the age of 2 years. Design. The study group consisted of 135 10‐ to 11‐year‐old children who had participated in the programme, including parent education, tooth‐brushing instruction and prescribed fluoride tablets (0.25 mg NaF) (2–3 years: 1 tablet/day; 3–5 years: 2 tablets/day). The prevalence of dental fluorosis in the study group was compared with that in a nonintervention reference group consisting of 129 children of the same ages. The analysis was based on photos of the permanent maxillary front teeth using the Thylstrup & Fejerskov (TF) Index. Results. No statistically significant difference in prevalence of dental fluorosis was seen between the two groups. Forty‐three percent of the children in the study group and 38% in the reference group had fluorosis, the majority of a mild nature (TF‐score 1). None had a TF score above 2. The pattern was the same after correction for parent reported intake of tablets at 3 and 5 years of age. Conclusion. Introduction of fluoride tablets at the age of 2 years did not result in increased prevalence of dental fluorosis.     

Self-Reported Health Status and Use of Medical Care by 3500 Adolescents in Western Sweden. I

ABSTRACT. Some 3500 adolescents answered a questionnaire anonymously. The sample represented 85 % of the students between the ages 13 to 16 and 65 % of the students between 17 to 18 in the three communities studied. The students all had middle class backgrounds. Self-reported illness differed considerably from data found in epidemiological surveys. The self-reported medical panorama was dominated by concerns about acne, tiredness, headaches, stomach pains, sports injuries and allergic disorders. One quarter to one third of the students reported such problems. Overall, 85% of the students reported that they were "completely healthy", at the same time as they also reported an average of 3.1 medical complaints. Self-initiated appointments with physicians were reported with an average of 5.5 during the last year, which is high. About 40% of the students had one complaint for which they wanted to see a physician. About 15% reported that they had had suicidal thoughts.     

Dose-Dependent Cytotoxicity of Chlorinated Hydrocarbons in Isolated Rat Hepatocytes

Dose-Dependent Cytotoxicity of Chlorinated Hydrocarbons in IsolatedRat Hepatocytes. DAHLSTROM-KJNG, L., COUTURE, J., LAMOUREUX,C, VAILLANCOURT, T., AND PLAA, G. L. (1990). Fundam. Appl. Toxicol.14, 833–841. The aim was to determine if isolated suspendedhepatocytes could differentiate between the effects of fourchlorinated hydrocarbons that are hepatotoxic In vivo and fourthat are not. Membrane integrity was assessed by measuring alanineaminotransferase (ALT) release after 30- to 180-min incubationsin vitro. From the results, the chlorinated hydrocarbons fellinto three groups: tetrachloroethylene and 1,1,2,2-tetrachloroeth-anewere the most potent cytotoxicants; CCl₄, 1,1,2-trichloroethane,and trichloroethylene exhibited intermediate cytotoxicity; andlow cytotoxicity was observed with CHCl₃, 1,1,1 -trichlo-roethane,and 1,1-dichloroethylene. Cytotoxicity ranking correlated poorlywith the reported In vivo hepatotoxicity of these agents. Theeffect of adding SKF-525A on the cytotoxicity of tetrachloroethyleneand CCI4 was also assessed. In addition, hepatocytes from ratspretreated with 2,5-hexanedione were used to determine if theywere more susceptible to the effects of CHCl₃, CCl₄ or tetrachloroethylene.SKF-525A decreased the cytotoxicity of both CO, and tetrachloroethylene,whereas pretreatment with 2,5-hexanedione enhanced their effect.The effects of both SKF-525A and 2,5-hexanedione on CCl in vitroare consistent with In vivo findings. However, tetrachloroethyleneis not hepatotoxic In vivo, suggesting that SKF-525A might actby stabilizing plasma membranes rendering the hepatocyte moreresistant to lysis. Overall, the results cast doubts on theuse of ALT release from isolated hepatocytes as an appropriatein vitro model for assessing hepatotoxic properties of chlorinatedhydrocarbons.     

Long-term-effects of two principally different antidepressant drugs on saliva secretion and composition

Abstract – In a double-blind, controlled, cross-over trial on 10 healthy volunteers, the effects of daily doses of maprotiline (75 mg) and zimelidine (100 mg) over a 14-day period were tested on saliva secretion rate and saliva composition. Based on current knowledge of salivary gland physiology and the difference in specificity between the two drugs, differences in salivary gland response could be expected. Since both drugs have anticholinergic effects which influence saliva secretion rate, the measured component concentrations had to be recalculated with regard to dependencies of secretion rate. Maprotiline, but not zimelidine, caused strong inhibition of secretion rate and accommodation ability. Maprotiline consistently caused around 50% increases in concentrations of the following saliva components: protein, amylase, fucose, hexose, sialic acid and potassium. The effects of zimelidine were less pronounced and resulted in initial increases of most organic components. 14 and 18 h after the intake of the drug these increases had disappeared and some of the components instead showed decreased concentrations. The results are consistent with current theories about facilitated serotoninergic and noradrenergic transmissions during treatment with antidepressants.     

Fermentation in ileostomy bags: Control of excessive gas with diet, pH and antibiotics

The composition of early morning gas from the bags of 10 ileostomates was determined using gas chromatography. Seven of the 10 had a predominance of gases attributable to bacterial fermentation (H₂ and CO₂, 70 ± 12%). The remaining three contained mainly atmospheric gases, N₂ and O₂, with only small amounts of fermentation gases (7 ± 3%).
When a controlled low fibre (0.7 g) dinner was substituted for a high fibre (13.5 g) evening meal, there was a corresponding decrease in the volume of fermentation gas in the ileostomy bag the next morning ( P < 0.05).
Gas production from ileostomy effluent was inhibited in vitro by 10 < pH < 5 and by antimicrobial agents. The most effective were metronidazole, chloramphenicol, tetracycline, erythromycin and chlorhexidine. These reduced fermentation gas by more than 95%.
It was concluded that the majority of the gas produced by ileostomates is formed by bacterial fermentation of the faecal waste in their ileostomy bag and that this may be controlled by careful manipulation of their diet.     

Studies of Plasma Fe59 Disappearance--A Manifestation of Ineffective Erythropoiesis and of Hemolysis

1. Studies of the plasma radioiron disappearance data have revealed arelative "elevation" of plasma radioactivity after the second day in normalsubjects, and after the first day in patients with hemolytic anemia, megaloblastic anemia and thalassemia. This elevation in plasma radioactivity in normal subjects may be interpreted as due to the return to plasma of radioironfrom those cells that are "ineffectively" produced and are hemolyzed in themarrow. Other interpretations are also presented.

2. Dyspoieses involving ineffective red cell economy, but not detectably affecting iron economy are contrasted with disorders involving ineffectiveutilization of iron and of pigment alone.

3. After the first day plasma radioiron activity shows a diurnal variationsimilar to the diurnal variation in plasma iron concentration.

Submitted on July 17, 1964 Accepted on September 29, 1964     

An in vivo method for microhardness measurements on human teeth

A non-destructive, in vivo method of measuring the enamel hardness directly on patients is described. Normal values on 39 students arc given and compared with those of five patients, one of whom suffered from abnormal oral acid concentration, and the others from the effects of various degrees of hyposialosis caused by radiologic treatment of tumors in head and neck. The difference between the two groups was significant below the 0.1% level. It was suggested that the method may be used to test the degree of salivary gland inactivation after radiologic treatment and the efficiency of different saliva substitutes used to alleviate the effects of hyposialosis.