Use of candles and risk of cardiovascular and respiratory events in a Danish cohort study

Burning candles at home emit small particles and gases that pollute indoor air. Exposure to fine particles in outdoor air has been convincingly linked to cardiovascular and respiratory events, while the associations with fine and ultrafine particles from candle burning remain unexplored. We examined the association between the use of candles and incident cardiovascular and respiratory events. We collected data on 6757 participants of the Copenhagen Aging and Midlife Biobank cohort recruited in 2009 and followed them up for the first hospital contact for incident cardiovascular and respiratory events until 2018. We investigated an association between the self-reported frequency of candle use in wintertime and cardiovascular and respiratory events, using Cox regression models adjusting for potential confounders. During follow-up, 1462 and 834 were admitted for cardiovascular and respiratory events, respectively. We found null associations between candle use and a hospital contact due to cardiovascular and respiratory events, with hazard ratios (HRs) and 95% confidence intervals (CI) of 0.97 (95% CI: 0.84, 1.11) and 0.98 (95% CI: 0.81, 1.18), respectively, among those using candles >4 times/week compared with <1 time/week. For cause-specific cardiovascular diseases, HRs were 1.10 (95% CI: 0.85, 1.43) for ischemic heart disease and 1.18 (95% CI: 0.77, 1.81) for myocardial infarction. For chronic obstructive pulmonary disease, HR was 1.26 (95% CI: 0.81, 1.97). We found no statistically significant associations between candle use and the risk of cardiovascular and respiratory events. Studies with improved exposure assessments are warranted.

Exposure to fine, ultrafine particles and black carbon in two preschools in nur-sultan city of kazakhstan

Children in preschools were studied as an exceptionally vulnerable group to lung diseases due to their immature immune system. Few data are available in the literature addressing the exposure of children in preschools to ultrafine (>10 nm) particles. Exposure of children to fine, ultrafine (10 nm-1 µm) particles and black carbon particles present inside and near two preschools in Nur-Sultan, Kazakhstan, during Fall 2019 was investigated. For Preschool I, the average daily (6 h) indoor (outdoor) PM₁ , PM_2.5 , and PM₁₀ concentrations over three-week measurements were 15.0 (SD 12.5) µg/m³ , 34.6 (SD 35.1) µg/m³ , and 47.2 (SD 45.2) µg/m³ , respectively. Average indoor UFP concentrations (>10.0 nm) including candle burning events were 5.20 × 10³ (SD 8.80 × 10³ ) particles/cm³ , with the background UFP concentration to be 3.30 × 10³ (SD 1.80 × 10³ ) particles/cm³ . In Preschool II, the average UFP concentration (>30.0 nm) in the morning and afternoon was 3.94 × 10³ (SD 5.34 × 10² ) and 3.36 × 10³ (SD 1.90 × 10³ ) particles/cm³ , respectively. Indoor black carbon (BC) concentrations were correlated with the outdoor smoking activity. The major sources of the indoor particles in the preschools were dust resuspension, candle burning, and infiltrated outdoor particles.

Axo-axonic structures in the medial prefrontal cortex of the rat: reduction by prenatal exposure to cocaine

The cognitive deficits associated with prenatal exposure to cocaine have been hypothesized to be the results of changes in the anatomy and function of the frontal cortex. In this study, pregnant dams were treated with cocaine (3 mg/kg i.v. twice a day) and the resulting adolescent (postnatal day, approximately 45) male offspring were killed for immunocytochemical determination of the total linear measure, number, location, and lengths of inhibitory GABA transporter-1 immunoreactive axo-axonic structures commonly called "candles" or "cartridges" in the medial prefrontal cortex. These inhibitory structures are the axon terminals of GABAergic cells that impinge on the initial axon segments of excitatory pyramidal neurons. We report that prenatal cocaine exposure decreased the number of these inhibitory candles. The greatest reduction of candles was observed in the ventral prelimbic cortex. Additionally, there was a subtle difference in the pattern of distribution of candles, namely the depth of the initial candle in the ventral portions of the prefrontal cortex was greater in rats exposed to prenatal cocaine. However, there was no overt change in the number of cells that were immunoreactive for the calcium-binding protein parvalbumin, an indicator of a subset of GABAergic interneurons that includes axo-axonic chandelier cells. We conclude that exposure to cocaine in utero disrupts the development of the axo-axonic cells in the prefrontal cortex and this disruption could contribute to the cognitive deficits reported with prenatal cocaine exposure.