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.     

Nutritional dose of magnesium in hypertensive patients on beta blockers lowers systolic blood pressure: a double-blind,cross-over study

Abstract. Objectives. To evaluate if magnesium alters blood pressure in hypertensive patients treated with beta blockers and if such effect can be coupled to a change in potassium and magnesium levels in muscle, serum and urine. Design. A randomized double-blind, cross-over study with magnesium and placebo taken orally, each for 8 weeks. Setting. Outpatient clinic, University Hospital, Umeå, Sweden. Subjects. Thirty-nine patients aged 26–69 years with moderate essential hypertension, treated before entry and during the study with continuous, unchanged beta blockers completed the study. Interventions. Random allocation to receive magnesium aspartate or placebo. Daily magnesium dose was 15 mmol(365 mg) distributed three times a day over 8 weeks. Main outcome measures. Blood pressure, serum, urine and muscle magnesium and potassium. Measurements performed at the start, after 8 and 16 weeks. Results. Systolic supine and standing blood pressure significantly decreased when magnesium was supplemented following placebo but not when magnesium was given at start. When magnesium and placebo groups were independently compared there was no significant change in supine and standing systolic and diastolic pressure. Serum and urine magnesium and serum potassium were significantly higher after magnesium treatment, whilst no change was present in urine potassium or in muscle magnesium and potassium. Conclusions. This study showed that 15 mmol magnesium day^-1 given to mild to moderate hypertensive patients treated with beta blockers could be the cause of a significant decrease in supine and standing systolic blood pressure.     

Cardiovascular Risk Factors in the Northern Sweden MONICA Study

ABSTRACT In the WHO MONICA Study, determinants and trends in cardiovascular disease are monitored during a 10-year period in 40 centers in 27 countries. The Northern Sweden MONICA Center is located furthest to the north of all participating centers. In this report, baseline data on cardiovascular risk factors are presented. In the first population screening, 1625 of 2000 (81%) invited individuals participated. Diastolic blood pressure ≤90 mmHg was recorded in 19% and 9% were on drug treatment for hypertension. Median cholesterol level was 6.10 mmol/1 and the frequency of hypercholesterolemia was high. A body mass index of ≤30, indicating severe obesity, was observed in 9%, a lower proportion than in most other European populations. Among men, the total proportion of tobacco consumers was 49%, including 22% snuffers. Of the women, 31% were tobacco consumers, very few being snuffers. Women had, in general, a more favorable cardiovascular risk factor profile up to the age of 45. Thereafter, the two genders were similar. By international comparisons, the population in northern Sweden is characterized by high serum cholesterol levels, intermediate blood pressure levels, a relatively low prevalence of severe obesity and a high consumption of smokeless tobacco.     

In Vitro Percutaneous Absorption of Cadmium from Water and Soil into Human Skin

The objective was to determine percutaneous absorption of cadmiumas the chloride salt from water and soil into and through humanskin. Soil (Yolo County 65-California-57-8) was passed through10-, 20-, and 48-mesh sieves. Soil retained by 80 mesh was mixedwith radioactive cadmium-109 at 13 ppb. Water solutions of cadmium-109at 116 ppb were prepared for comparative analysis. Human cadaverskin was dermatomed to 500-µm, and used in glass diffusioncells with human plasma as the receptor fluid (3 ml/hr flowrate) for a 16-hr skin application time. Cadmium in water (5µ1/cm²) penetrated skin to concentrations of 8.8 ±0.6 and 12.7 ± 11.7% of the applied dose from two humanskin sources. Percentage doses absorbed into plasma were 0.5± 0.2 and 0.6 ± 0.6%, respectively. Cadmium fromsoil (0.04 g soil/cm²) penetrated skin at concentrations of0.06 ± 0.02 and 0.13 ± 0.05% for the two humanskin sources. Amounts absorbed into plasma were 0.01 ±0.01 and 0.07 ± 0.03%. Most of the non-absorbed cadmiumwas recovered in the soap and water skin surface wash. Bindingof cadmium from water to soil was greater than binding fromwater to powdered human stratum corneum, supporting the lowerabsorption from soil than from water. Short-term exposure ofcadmium in water to human skin for 30 min (bath or swim) resultedin skin uptake, which upon further perfusion (48 hr), absorbedinto the plasma receptor fluid (systemic). Cadmium in soil wasincreased from 6.5 to 65 ppb. Skin levels correspondently increased,but plasma receptor fluid levels remained constant. Soil capacitywas decreased from 40 to 4 mg/cm². Skin levels correspondinglydecreased, suggesting decreased skin contact, but plasma receptorfluid levels remained constant. The above suggest that, within vitro diffusion, the surface concentration of cadmium willinfluence skin cadmium concentration, but that absorption intoplasma receptor fluid is relatively independent of skin surfaceconcentrations. Calculations suggest that a daily whole bodyexposure to cadmium at 116 ppb with 0.5% absorption will resultin daily systemic intake of about 10 µg Cadmium.     

The cost-effectiveness of treating hypertension in elderly people—an analysis of the Swedish Trial in Old Patients with Hypertension (STOP Hypertension)

Abstract. Objectives. The aim of this study was to estimate the cost-effectiveness of antihypertensive treatment in elderly people based on the results of the Swedish Trial in Old Patients with Hypertension (STOP Hypertension). Design. The STOP Hypertension study was a randomized trial comparing active antihypertensive treatment with a placebo. The risk of stroke, cardiovascular disease and total mortality was significantly reduced in the actively treated group compared to placebo. Setting. One hundred and sixteen primary health care centres in Sweden. Subjects. A total of 1627 hypertensive patients aged 70–84. No patient was lost to follow-up. Interventions. Antihypertensive treatment with beta blockers and diuretics for a mean follow-up of 25 months. Main outcome measure. The cost-effectiveness ratio estimated as the net cost (the treatment cost minus saved costs of reduced cardiovascular morbidity) divided by the number of life-years gained (the increase in life expectancy from treatment). Results. The cost per life-year gained was estimated as SEK 5000 for men and SEK 15000 for women ($1 = SEK6; £1 = SEK10). The cost per life-year gained did not exceed SEK100000 in any of the sensitivity analyses. Conclusions. It is concluded that treatment of elderly hypertensive patients with beta blockers and/or diuretics is cost-effective according to the results of the STOP Hypertension study.