History of parvovirus B19 infection is associated with silent cerebral infarcts

BACKGROUND

The relationship between silent cerebral infarcts (SCIs) and history of parvovirus B19 (B19V) has not been systematically evaluated. As an ancillary study from the Silent Cerebral Infarct Trial (SIT) (NCT00072761), we tested the hypothesis that a history of B19V infection is associated with an increased prevalence of SCIs in children with sickle cell anemia.

PROCEDURE

We used a retrospective cross-sectional cohort study design; each participant underwent a brain magnetic resonance imaging (MRI) scan and medical record review for prior B19V infection (n = 958).

RESULTS

SCI was present in 30% (287 of 958) of participants and 17% (165 of 958) had a history of B19V infection. Based on prior evidence that low baseline hemoglobin (Hgb) levels are associated with increased odds of SCI, Hgb levels were divided into tertiles (<7.6 g/dl, ≥7.6-≤8.5 g/dl, ≥8.6 g/dl) and multivariable analysis was used to determine the relationship between the joint effect of prior B19V infection, Hgb levels, and SCI. Prior B19V infection and the lowest Hgb tertile were associated with increased risk of SCI (odds ratio [OR] 2.12; 95% CI, 1.17-3.84; P = 0.013); no prior B19V infection and the highest Hgb tertile were associated with a decreased risk (OR 0.56; 95% CI, 0.38-0.84; P = 0.004).

CONCLUSIONS

Efforts to decrease the incidence of B19V infection, such as the development of a B19V vaccine, may decrease SCI prevalence.

Enablers and barriers in delivery of a cancer exercise program: the Canadian experience

BACKGROUND

Exercise is an important therapy to improve well-being after a cancer diagnosis. Accordingly, cancer-exercise programs have been developed to enhance clinical care; however, few programs exist in Canada. Expansion of cancer-exercise programming depends on an understanding of the process of program implementation, as well as enablers and barriers to program success. Gaining knowledge from current professionals in cancer-exercise programs could serve to facilitate the necessary understanding.

METHODS

Key personnel from Canadian cancer-exercise programs (n = 14) participated in semistructured interviews about program development and delivery.

RESULTS

Content analysis revealed 13 categories and 15 subcategories, which were grouped by three organizing domains: Program Implementation, Program Enablers, and Program Barriers. ■ Program Implementation (5 categories, 8 subcategories) included Program Initiation (clinical care extension, research project expansion, program champion), Funding, Participant Intake (avenues of awareness, health and safety assessment), Active Programming (monitoring patient exercise progress, health care practitioner involvement, program composition), and Discharge and Follow-up Plan.■ Program Enablers (4 categories, 4 subcategories) included Patient Participation (personalized care, supportive network, personal control, awareness of benefits), Partnerships, Advocacy and Support, and Program Characteristics.■ Program Barriers (4 categories, 3 subcategories) included Lack of Funding, Lack of Physician Support, Deterrents to Participation (fear and shame, program location, competing interests), and Disease Progression and Treatment.

CONCLUSIONS

Interview results provided insight into the development and delivery of cancer-exercise programs in Canada and could be used to guide future program development and expansion in Canada.

Risk perception and psychological morbidity in men at elevated risk for prostate cancer

OBJECTIVE

As prostate-specific antigen (psa) makes prostate cancer (pca) screening more accessible, more men are being identified with conditions that indicate high risk for developing pca, such as elevated psa and high-grade intraepithelial neoplasia (hgpin). In the present study, we assessed psychological well-being and risk perception in individuals with those high-risk conditions.

METHODS

A questionnaire consisting of a psychological symptom survey, a trait risk-aversion survey, and a cancer-specific risk perception survey was administered to 168 patients with early-stage localized pca and 69 patients at high risk for pca (n = 16 hgpin, n = 53 psa > 4 ng/mL). Analysis of variance was used to examine differences in psychological well-being and appraisal of risk between the groups.

RESULTS

Compared with the pca group, the high-risk group perceived their risk of dying from something other than pca to be significantly lower (p = 0.007). However, pca patients reported significantly more clinically important psychological symptoms.

CONCLUSIONS

The identification of prostate conditions that predict progression to cancer might not result in the psychological symptoms commonly experienced by pca patients, but does appear to be related to a distorted perception of the disease's mortal risk. Patients with pca experience reduced psychological well-being, but better understand the risks of pca recurrence and death. Education on the risks and outcomes of pca can help at-risk men to view health assessments with reduced worry.

Marginal zinc deficiency in older adults: responsiveness of zinc status indicators

OBJECTIVE

Suspicions that mild zinc deficiency is common among the elderly cannot be confirmed or refuted because definitive indicators of zinc status are lacking. The goal of this study was to document the clinical responsiveness of parameters of zinc status in a group of older adults consuming a carefully controlled diet: first moderately low in zinc (3.97 mg/day for 15 days) and then high in zinc (28.19 mg/day for 6 days).

METHODS

Fifteen older adults (mean age = 66.6 yrs) volunteered to consume a marginally zinc-deficient diet for 15 days followed by 6 days of zinc repletion. Plasma concentrations of erythrocyte metallothionein and the enzyme 5'-nucleotidase, as well as levels of zinc, alkaline phosphatase, copper and ceruloplasmin were measured before and after zinc depletion and repletion.

RESULTS

Plasma zinc levels were not altered during the study. Alkaline phosphatase (AP) values did not change in the expected direction, although a small decrease in AP following zinc repletion was statistically significant. Erythrocyte metallothionein results followed a pattern similar to that of alkaline phosphatase, little change, but a small, statistically significant drop after zinc repletion. As expected, there were no diet-associated changes in plasma copper and ceruloplasmin levels. In contrast, plasma concentrations of the enzyme 5'-nucleotidase decreased (p < 0.01) from 2.7 +/- 0.5 to 1.1 +/- 0.5 U during zinc depletion and increased (p < 0.05) to 2.2 +/- 0.4 U after 6 days of repletion.

CONCLUSIONS

Mild zinc deficiency is difficult to detect. In this study, traditional indicators such as plasma zinc and alkaline phosphatase did not change as would be expected in response to alterations in zinc intake. Likewise, erythrocyte metallothionein did not respond to altered zinc intakes as expected but this factor may reflect long-standing or more severe zinc depletion and thus requires additional study. Activity of the enzyme 5'-nucleotidase appears responsive to acute changes in zinc intake; however, more work is needed to define how well these activities will reflect zinc intake in other types of subjects.

Cyclosporin-A increases synthesis of 1,25-dihydroxyvitamin D3 in the rat and mouse

We have previously observed elevated serum 1,25-dihydroxyvitamin D3 [1,25-(OH)2D] levels in male rats treated with oral cyclosporin-A (CsA). This elevation was independent of changes in PTH, ionized calcium, or phosphate. This paper investigates the potential sources and mechanisms for this increase in both rats and mice. Kidney homogenates from rats treated for 14 days with (15 mg/kg) had a significant increase in 25-hydroxyvitamin D (25OHD)-24-hydroxylase (24-hydroxylase) activity (149 +/- 20 vs. 89 +/- 16 fmol/mg.min; P less than 0.05), but nonsignificant increases in 25OHD-1 alpha-hydroxylase (1 alpha-hydroxylase) activity compared to controls. Kidney homogenates from C57b16J mice after the administration of 30-50 mg/kg CsA for 3 days revealed a linear dose-related increase in renal 1 alpha-hydroxylase (r = 0.96; P less than 0.05), which became significant with doses of 30 mg/kg CsA or more (P less than 0.05). To investigate the source of this 1,25-(OH)2D production, serum 1,25-(OH)2D was measured before and 48 h after bilateral nephrectomy in rats receiving CsA for 16 days. The percent decrease in serum 1,25-(OH)2D values was not significantly different in CsA-treated and untreated rats (33.9 +/- 4.9% vs. 47.5 +/- 4.9%), indicating little or no contribution from nonrenal sources. Studies of MCRs and production rates (PRs) revealed that the elevated 1,25-(OH)2D values were due to enhanced production and not altered clearance (PR, 12.4 +/- 1.2 vs. 19.1 +/- 1.9 fmol/mg.min; P less than 0.01). CsA increases 1 alpha-hydroxylase activity and produces significant elevations in serum 1,25-(OH)2D levels in both rats and mice. This increase may have an impact on bone mineral metabolism and immune modulation in postorgan transplantation patients.

Concentrations of diazinon, chlorpyrifos, and bendiocarb after application in offices

Airborne and surface concentrations of diazinon, chlorpyrifos (Dursban), and bendiocarb (Ficam) were measured at intervals up to 10 days after broadcast spray application onto the floors of seven offices. Results from this work can provide information to evaluate health hazards for workers and others entering treated buildings and can assist public agencies in setting guidelines or regulations. Diazinon and chlorpyrifos airborne concentrations peaked 4 hr after application at 163 and 27 micrograms/m3 of air sampled, respectively. The highest level of bendiocarb (2.7 micrograms/m3) was measured during treatment. Airborne concentrations measured for diazinon indicate that building occupants should not enter unventilated rooms for at least 2 days after spraying. Reentry into unventilated rooms 1 day after treatment with chlorpyrifos or bendiocarb would appear to be safe, however. Residues on aluminum plates and furniture were examined at intervals of up to 48 hr after spraying. In many cases, surface concentrations were higher at 24 or 48 hr than at 1 hr. Concentrations of residues removed from wood and painted metal furniture generally were higher than those on the aluminum plates. Peak residue concentrations were diazinon, 38 ng/cm2 of surface area sampled at 48 hr; chlorpyrifos, 5.9 ng/cm2 at 48 hr; and bendiocarb, 25 ng/cm2 at 1 and 24 hr. Workers who must enter buildings after insecticide application often are unaware of treatment plans and, therefore, are unable to take precautions to minimize their exposure. Inhalation and skin contact with insecticides can be reduced by providing office workers and building occupants with information on treatment times, health effects of insecticide overexposure, steps to take to reduce contact, and the perceived health risk. It is essential that treated areas be ventilated adequately before workers return to their offices.