RESUMO
The environmental impact of natural occurrences of asbestos (NOA) and asbestos-like minerals is a growing concern for environmental protection agencies. The lack of shared sampling and analytical procedures hinders effectively addressing this issue. To investigate the hazard posed by NOA, a multidisciplinary approach that encompasses geology, mineralogy, chemistry, and toxicology is proposed and demonstrated here, on a natural occurrence of antigorite from a site in Varenna Valley, Italy. Antigorite is, together with chrysotile asbestos, one of the serpentine polymorphs and its toxicological profile is still under debate. We described field and petrographic analyses required to sample a vein and to evaluate the NOA-hazard. A combination of standardized mechanical stress and automated morphometrical analyses on milled samples allowed to quantify the asbestos-like morphology. The low congruent solubility in acidic simulated body fluid, together with the toxicity-relevant surface reactivity due to iron speciation, signalled a bio-activity similar or even greater to that of chrysotile. Structural information on the genetic mechanism of antigorite asbestos-like fibres in nature were provided. Overall, the NOA site was reported to contain veins of asbestos-like antigorite and should be regarded as source of potentially toxic fibres during hazard assessment procedure.
RESUMO
BACKGROUND: Arterial hypertension is very common in chronic kidney disease (CKD) patients and its prevalence increases with lowering estimated glomerular filtration rate (eGFR). Blood pressure (BP) control is a cornerstone in the treatment of CKD patients but still most treatment decisions are based on office BP measurement (OBPM). The aim of this cross-sectional, retrospective study is to investigate the prevalence of hypertension phenotypes in CKD patients and whether different home (HBPM) or OBPM are associated with a different CKD stage and cardiovascular comorbidities. METHODS: We analyzed 560 consecutive patients (359 men, age 70±13 years), affected by stage 3-5 CKD, who performed HBPM recording; OBPM during a single visit was also assessed. Uncontrolled hypertension was defined as OBPM values ≥140/90 mmHg and HBPM values ≥135/85 mmHg, respectively. RESULTS: Systolic and diastolic HBPM values were lower than OBPM values. A white coat effect (systolic BP +18±12 mmHg) was detected in 62.5%, while a masked effect (systolic BP -14±10 mmHg) was detected in 22.7%. No relationship was found between BP differences and body weight, CKD stage, eGFR or presence of diabetes. Based on OBPM, 18.6% of patients showed controlled systolic and diastolic BP, whereas 37.8% had sustained hypertension. White-coat hypertension was detected in 23.4% and Masked hypertension in 12.1%. The multiple logistic regression model showed that masked uncontrolled hypertensive patients showed a higher probability of having ischemic heart disease (OR=2.54 [1.02-6.36]), while sustained hypertension was associated with an increased prevalence of stroke in comparison to normotensive or true control BP group (OR=4.72 [1.30-17.07]). Age, gender, diabetes or CKD stage, were not different among the four hypertension phenotypes. CONCLUSIONS: We observed a quite high rate of masked uncontrolled hypertension and of white coat hypertension in stage 3-5ND CKD patients. Office BP measurement, as a single tool, is an inadequate diagnostic procedure in the clinical management of CKD patients. HBPM should be routinely implemented for identifying hypertensive phenotypes and then for avoiding misdiagnosis and mistreatment of pre-dialysis CKD patients in a tertiary care setting.
