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Objective: To study the age and sex influence on bone and blood lead concentrations in a cohort of the general population living in Toronto. Approach: A 109Cd K x-ray fluorescence (KXRF) measurement system was used from 2009 to 2011 in a study that measured the bone lead (Pb) concentration of 263 environmentally exposed individuals residing in Toronto, Ontario, Canada. Tibia (cortical bone) and calcaneus (trabecular bone) lead contents were measured in 134 males and 129 females between 1 and 82 years of age. Whole blood Pb concentration was measured by TIMS (thermal ionization mass spectrometer). Tibia (Ti) and calcaneus (Cal) Pb were examined versus the age of participants, taking into account uncertainties in bone Pb measurement values. Main results: No significant sex differences were observed in any of the age categories. Participants older than 50 years of age demonstrated the highest concentrations of Pb in their blood, tibia, and calcaneus bones. Significance: In most of the previous publications, uncertainty was not considered in the regression model of bone Pb and age. However, in this paper, we adjusted the bone Pb values for the uncertainty level. This had a significant influence in regression models of bone Pb and thus we recommend that uncertainty be considered in future studies.

BACKGROUND/OBJECTIVES: Little is known about the dermoscopic features of atypical fibroxanthoma. METHODS: This was a case-control study. Atypical fibroxanthoma lesions were compared with a control group with non-melanoma skin cancer. RESULTS: Altogether 40 atypical fibroxanthoma were collected. Most developed in men (93%), appearing mainly as nodular (63%), amelanotic (93%) and ulcerated (78%) lesions. Most lesions were located on the scalp (55%) and the ears (13%). Dermoscopically, most atypical fibroxanthoma displayed red (83%) and white (70%) structureless areas and irregular linear vessels (43%). A series of features achieved statistical significance when comparing atypical fibroxanthoma with non-melanoma skin cancer. The presence of red and white structureless areas and white lines, and the absence of yellowish-white opaque scales, hairpin vessels and arborising vessels were predictive of atypical fibroxanthoma in univariate analysis. However, when squamous cell carcinoma was excluded from the analysis, none of the criteria achieved statistical significance. When basal cell carcinoma was excluded, three variables achieved statistical significance in predicting atypical fibroxanthoma: red, structureless areas, the absence of opaque yellowish-white scales and absence of white circles. CONCLUSIONS: Atypical fibroxanthomas seem to be barely distinguishable from basal cell carcinoma dermoscopically, but they are more easily distinguishable from a well to moderately differentiated squamous cell carcinoma. A histopathological examination is needed for the final diagnosis.

Manganese (Mn) is an essential element for humans, animals, and plants and is required for growth, development, and maintenance of health. Studies show that Mn metabolism is similar to that of iron, therefore, increased Mn levels in humans could interfere with the absorption of dietary iron leading to anemia. Also, excess exposure to Mn dust, leads to nervous system disorders similar to Parkinson's disease. Higher exposure to Mn is essentially related to industrial pollution. Thus, there is a benefit in developing a clean non-invasive technique for monitoring such increased levels of Mn in order to understand the risk of disease and development of appropriate treatments. To this end, the feasibility of Mn measurements with their minimum detection limits (MDL) has been reported earlier from the McMaster group. This work presents improvement to Mn assessment using an upgraded system and optimized times of irradiation and counting for induced gamma activity of Mn. The technique utilizes the high proton current Tandetron accelerator producing neutrons via the (7)Li(p,n)(7)Be reaction at McMaster University and an array of nine NaI (Tl) detectors in a 4 π geometry for delayed counting of gamma rays. The neutron irradiation of a set of phantoms was performed with protocols having different proton energy, current and time of irradiation. The improved MDLs estimated using the upgraded set up and constrained timings are reported as 0.67 μgMn/gCa for 2.3 MeV protons and 0.71 μgMn/gCa for 2.0 MeV protons. These are a factor of about 2.3 times better than previous measurements done at McMaster University using the in vivo set-up. Also, because of lower dose-equivalent and a relatively close MDL, the combination of: 2.0 MeV; 300 μA; 3 min protocol is recommended as compared to 2.3 MeV; 400 μA; 45 s protocol for further measurements of Mn in vivo.

We present a case report of a microcystic adnexal carcinoma on the cheek of a 67-year-old man. Clinical, dermatoscopic and dermatopathologic images are presented. A search of the literature has not discovered any previously published dermatoscopy images of microcystic adenexal carcinoma.

Several studies with animals have shown that even low and medium prenatal and postnatal exposure to methylmercury (MeHg) can result in locomotor, motor coordination and learning deficits. However, some behavioural effects of MeHg remain controversial and the methods to model human MeHg exposure in animal still remain to be optimized. We investigated the neurobehavioral effects of two different patterns of MeHg exposure. MeHg was given mixed in palatable food that mice readily ate. For the first pattern (chronic group), C57BL/6 mice dams were given 1.4 microg/g body weight (BW)/day (n=20) throughout gestation mixed in palatable food. For the second pattern (bolus) dams were given 6.0 microg/g BW/day mixed in palatable food on gestation day 12 and 16 together with a lower chronic dose of 0.85 microg/g BW/day mixed in palatable food on all remaining gestation days (n=20). Day 12 and 16 were chosen because neuron proliferation and the start of migration for many brain regions occur during that period. Behavioural testing on weanling animals started at 8 weeks. Both the chronic and bolus groups showed an impairment of working memory and visual spatial ability in the radial arm maze task. Other tests did not provide clear evidence that methylmercury exposure had significant adverse effects on locomotor activity, motor coordination or emotional reactivity. However, the chronic groups had a tendency for lower performance in most tests including activity in Skinner box and open field trials, as well as a higher number of anxiety-like behaviors. Chronic exposure to lower levels of MeHg combined to acute exposure with high levels of a few days during gestation appears to be less damaging than chronic exposure to slightly higher levels without acute MeHg exposure even though, equal amounts were administered during gestation. Possibly, as indicated by preliminary data, the relatively larger impact of chronic administration of a higher daily dose could be the consequence of a higher brain MeHg burden in pups compared to brain MeHg levels in the pups from dams receiving a smaller daily dose with 2 large doses on gestation day 12 and 16. Alternatively, bolus MeHg could have had a larger impact if administered on different gestation days when some neural development processes are more sensitive to MeHg.

The Canadian population is currently subject to low, chronic lead exposure and an understanding of its effects is of great significance to the population's health. Such low exposure is difficult to measure directly; approximation by physiologically based modeling may provide a preferable approach to population analysis. The O'Flaherty model of lead kinetics is based on an age-dependent approach to human growth and development and devotes special attention to bone turnover rates. Because lead is a bone-seeking element, the model was deemed ideal for such an analysis. Sample from 263 individuals of various ages from the Greater Toronto Area were selected to evaluate the applicability of the current version of the O'Flaherty model to populations with low lead exposure. For each individual, the input value of lead exposure was calibrated to match the output value of cortical bone lead to the individual's measured tibia lead concentration; the outputs for trabecular bone, blood, and plasma lead concentrations obtained from these calibrations were then compared with the subjects' measured calcaneus, blood, and serum lead concentrations, respectively. This indicated a need for revision of the model parameters; those for lead binding in blood and lead clearance from blood to bone were adjusted and new outputs were obtained in the same fashion as before. Model predictions of trabecular lead concentration did not agree with measurements in the calcaneus. The outputs for blood and plasma lead concentrations were highly scattered and, on an individual level, inconsistent with corresponding measurements; however, the general trends of the outputs matched those of the measurements reasonably well, which indicates that the revised blood lead binding and lead clearance parameters may be useful in future studies. Overall, the analysis showed that with the revisions to the model discussed here, the model should be a useful tool in the analysis of human lead kinetics and body burden in populations characterized by low, chronic exposure to lead from the general environment.

We present a case of a clonal nevus arising from a previously banal melanocytic nevus over a 15-month period on the central back of a 30-year-old woman in a primary care skin cancer practice in Melbourne, Australia. Clinical, dermatoscopic and dermatopathologic images are presented. A search of the literature has discovered no previously published dermatoscopy images of an evolving clonal nevus.

A 109Cd K X-ray fluorescence (KXRF) measurement system consisting of four detectors in clover-leaf geometry is a non-invasive, low-radiation-dose method of measuring bone lead concentration. Its high precision in estimating the bone lead content makes it a promising tool for the determination of the low levels of lead currently found in the general population. After developing the clover-leaf geometry system, the system was used for the first time in a major survey in 2008 to measure the lead levels of 497 smelter employees (an occupationally exposed group with high lead levels). Since the delivered effective dose of the bone lead system in clover-leaf geometry is small (on the order of nSv), the technique can be used to measure the bone lead of sensitive populations such as the elderly and children. This detector system was used from 2009 to 2011, in a pilot study that measured the bone lead concentration of 263 environmentally exposed individuals (termed the EG group) residing in Toronto, Ontario, Canada. In this paper, the factors that influence uncertainties in lead content in tibia (cortical bone) and calcaneus (trabecular bone) are discussed based on gender, age, and body mass index (BMI) by using analysis of variance (ANOVA) and multiple linear regression models. Results from the two study groups (the EG group versus the occupationally exposed smelter employees) are compared where appropriate (i.e. for males older than 20). Results from univariate analyses showed that females have higher tibia uncertainty compared to males. We observed significant differences for both calcaneus and tibia uncertainty measures (p < 0.0005) among different age groups, where the uncertainties were highest in the lowest age group (

We present a case report of an atypical fibroxanthoma on the cheek of a 73-year-old man. Clinical, dermatoscopic and dermatopathologic images are presented.

Fluorine is an element that can be either beneficial or harmful, depending on the total amount accumulated in the teeth or bones. In our laboratory, we have developed a non-invasive technique for the in vivo measurement of fluoride in bone using neutron activation analysis and performed the first pilot human study. Fluoride in humans is quantified by comparing the γ-ray signal from a person to the γ-ray signal obtained from appropriate anthropomorphic calibration phantoms. An identified problem with existing fluoride phantoms is contamination with aluminum. Aluminum creates an interfering γ-ray signal which, although it can be subtracted out, increases the uncertainty in the measurement and worsens the detection limit. This paper outlines a series of studies undertaken to develop a better calibration phantom for fluorine measurement, which does not have aluminum contamination.