Total body iron overload in welder's siderosis

Welder's siderosis occurs as a consequence of the inhalation of iron dust. The iron overload of welder's siderosis is usually considered to be confined to the lungs. Here we present three proven cases of welder's siderosis associated with evidence of increased total systemic iron stores, as evidenced by increased serum ferritin levels. Multiple investigations including molecular genotyping for the common mutations found in genetic haemochromatosis failed to prove this was due to haemochromatosis, nor was there any evidence of any other recognised cause of systemic iron overload. Thus the systemic iron overload described seems likely to be due to either occupational exposure, an uncharacterised genetic haemochromatosis, or a combination of both.     

Meeting calcium recommendations during middle childhood reflects mother-daughter beverage choices and predicts bone mineral status

BACKGROUND: Longitudinal data regarding the influence of beverage intakes on calcium adequacy are lacking. OBJECTIVE: This study evaluated calcium intake from ages 5 to 9 y as a function of mother-daughter beverage choices and as a predictor of bone mineral status. DESIGN: Intakes of energy, calcium, milk, sweetened beverages, fruit juices, and non-energy-containing beverages were measured with the use of three 24-h dietary recalls in 192 non-Hispanic white girls aged 5, 7, and 9 y and their mothers. Calcium intakes from ages 5 to 9 y were categorized as either meeting or falling below recommended adequate intakes (AIs). The girls' bone mineral status was assessed with dual-energy X-ray absorptiometry at age 9 y. RESULTS: The mean 5-y calcium intake was related to bone mineral density at age 9 y (beta = 0.27, P < 0.001). The girls who met the AI for calcium were not heavier (P = 0.83) but had higher energy intakes (P < 0.0001) than did the girls who consumed less than the AI. Compared with the girls who consumed less than the AI, the girls who met the AI consumed, on average, almost twice as much milk (P < 0.0001), had smaller decreases in milk intake (P < 0.01), and consumed 18% less sweetened beverages (P < 0.01) from ages 5 to 9 y; the 2 groups did not differ significantly in juice and non-energy-containing beverage intakes. The girls who met the AI were also served milk more frequently than were the girls who consumed less than the AI (P < 0.0001) and had mothers who drank milk more frequently (P < 0.01) than did the mothers of the girls who consumed less than the AI. CONCLUSIONS: These findings provide new longitudinal evidence that calcium intake predicts bone mineral status during middle childhood and reflects mother-daughter beverage choice patterns that are established well before the rapid growth and bone mineralization observed in adolescence.     

Pharmacokinetics of remifentanil and its major metabolite, remifentanil acid, in ICU patients with renal impairment

Background. The pharmacokinetics of remifentanil, an opioidanalgesic metabolized by non-specific esterases, and its principalmetabolite, remifentanil acid (RA), which is excreted via thekidneys, were assessed as part of an open-label safety studyin intensive care unit (ICU) patients with varying degrees ofrenal impairment. Methods. Forty adult ICU patients with normal/mildly impairedrenal function (creatinine clearance [CL_cr] 62.9 (SD) 14.5 mlmin^–1; n=10) or moderate/severe renal impairment (CL_cr14.7 (15.7) ml min^–1; n=30) were included. Remifentanilwas infused for up to 72 h, at a starting rate of 6–9µg kg^–1 h^–1 titrated to achieve a target sedationlevel, with additional propofol (0.5 mg kg^–1 h^–1)if required. Intensive arterial sampling was performed for upto 72 h after infusion. Pharmacokinetic parameters obtainedby simultaneous modelling of remifentanil and RA data were statisticallycompared between the two groups. Results. Remifentanil pharmacokinetics were not significantlyaffected by renal status. RA clearance in the moderate/severegroup was reduced to about 25% that of the normal/mild group(41 (29) vs 176 (49) ml kg^–1 h^–1, P<0.0001).Metabolic ratio, a predictor of the ratio of RA to remifentanilconcentrations at steady state, was approximately eight-foldhigher in the moderate/severe group relative to the normal/mildgroup (116 (110) vs 15 (4), P<0.0001). Maximum RA levelsapproached 700 ng ml^–1 in the moderate/severe group. Conclusions. Although RA accumulates in patients with moderate/severerenal impairment, pharmacokinetic modelling predicts that RAconcentrations during a 9 µg kg^–1 h^–1 remifentanilinfusion for up to 15 days would not exceed those reported inthe present study, for which no associated prolongation of µ-opioideffects was observed. Br J Anaesth 2004; 92: 493–503     

The Effects of Sieving and Spatial Variability of Estuarine Sediment Toxicity Samples on Sediment Chemistry

In 1998, we conducted a field-validation study of the chronic 28-day whole-sediment toxicity test with Leptocheirus plumulosus in Baltimore Harbor, MD, an area where this amphipod is indigenous. This study included an evaluation of the effect of sieving on sediment chemical concentrations and the use of field replicates, or separate grabs from the same site, which provided an estimation of within-site chemical and toxicologic variability. Six stations in Baltimore Harbor, MD, were included in this evaluation. Chemical analysis of two separate unsieved field replicates from the six sites indicated that, overall, the chemical concentrations of replicates within each site were similar, especially for metals. Organic contaminants particularly total PCBs, had the highest variability between replicates. Chemical variability did not appear to be related to differences in organic carbon content or grain size or to variability in toxicologic end points. Results supported the use of composite samples in sediment toxicity tests. In addition, in most cases, sieving had little effect on sediment chemistry. For the metals and trace elements, only selenium showed a substantial change after sieving, with some samples increasing after sieving and others decreasing. Concentrations of acid-volatile sulfide (AVS) increased 194.6% at one station after sieving, although in most other cases, AVS and simultaneously extracted metals remained relatively unchanged. As expected, concentrations of organics generally decreased after sieving, but in the majority of cases this decrease was small (i.e., coefficient of variation 25%). Total benzene hexachloride and total chlordanes had the greatest changes, whereas polychlorinated biphenyl concentrations decreased at only two stations after sieving. Concentrations of polyaromatic hydrocarbons showed little change after sieving. These changes in sediment chemistry due to sieving must be viewed in the larger context of the potentially confounding effects that indigenous organisms may have on the interpretation of test results from whole-sediment toxicity tests.     

Femur fractures in infants and young children

Using an administrative database, we determined rates of femur fracture by year of age for children younger than 6 years and by month of age. The highest rate of femur fracture was in children younger than 1 year and in 2-year-olds; the greatest number of fractures occurred during the third month of life. While femur fractures in children are often due to accidental injury, the reasons for the peak in the first year and the subsequent decline are not clear.     

Increased awareness, knowledge and utilization of preconceptional folic acid in Israel following a national campaign

BACKGROUND: To decrease the risk of neural tube defects (NTDs), the Israeli Ministry of Health (MOH) issued guidelines in August 2000 recommending daily folic acid (FA) supplementation for women in their childbearing age, and concurrently launched a national FA campaign. Campaign effects were assessed by comparing the results of a survey done in 2002 with a baseline survey done in June 2000. METHODS: Both surveys were done within the network of the Public Health Services' Mother and Child Health Clinics (MCHC). Nursing staff conducted structured interviews of pregnant women and mothers of newborn infants. RESULTS: In the 2002 survey (n = 1661), awareness was 85%, correct knowledge was 77.7% and 30.5% utilized FA preconceptionally. Ratios of awareness, knowledge and utilization were highest among women with post-university education (93%, 84%, 46%), and awareness and utilization were significantly higher in the 25-29 year age bracket (90%, 35%). In the baseline 2000 survey (n = 1719), FA awareness had been 54.6%, knowledge of the benefits of FA was 17.6% and preconceptional utilization was reported by a mere 5.2%. CONCLUSIONS: A national periconceptional FA campaign in Israel resulted in significant increases in awareness and correct knowledge, and a sixfold increase in its intake.     

The effects of carbon monoxide on respiratory chemoreflexes in humans

As protection against low-oxygen and high-carbon-dioxide environments, the respiratory chemoreceptors reflexly increase breathing. Since CO is also frequently present in such environments, it is important to know whether CO affects the respiratory chemoreflexes responsiveness. Although the peripheral chemoreceptors fail to detect hypoxia produced by CO poisoning, whether CO affects the respiratory chemoreflex responsiveness to carbon dioxide is unknown. The responsiveness of 10 healthy male volunteers were assessed before and after inhalation of approximately 1200 ppm CO in air using two iso-oxic rebreathing tests; hypoxic, to emphasize the peripheral chemoreflex, and hyperoxic, to emphasize the central chemoreflex. Although mean (SEM) COHb values of 10.2 (0.2)% were achieved, no statistically significant effects of CO were observed. The average differences between pre- and post-CO values for ventilation response threshold and sensitivity were -0.5 (0.9) mmHg and 0.8 (0.3) L/min/mmHg, respectively, for hyperoxia, and 0.7 (1.1) mmHg and 1.2 (0.8) L/min/mmHg, respectively, for hypoxia. The 95% confidence intervals for the effect of CO were small. We conclude that environments with low levels of CO do not have a clinically significant effect acutely on either the central or the peripheral chemoreflex responsiveness to carbon dioxide.