Renal hypertension

The advances in our knowledge of renal hypertension over the last 75 years represents outstanding accomplishments in experimental and clinical medicine. A review of the highlights of this important investigation in hypertension should begin with Tigerstedt and Bergman\u27s work in Scandinavia which demonstrated in 1898, that extracts of kidney possessed a hypertensive action. They gave the name renin to the impure substance which produced this effect. For the next 30 years much work was done on the vasoconstrictor action of extracts of the adrenal medulla, the nervous system and the kidney

New Configurations of Silicone Passive Sampling Devices: Quantifying Feline and Firefighter Chemical Exposures

Silicone wristbands are passive sampling devices (PSD) that sequester bioavailable organic chemicals in the environment. In environmental health studies, silicone wristbands are easy to wear and can provide personal exposure data about complex chemical mixtures. This dissertation includes an overview of PSD technology, a literature review of current wristband research publications, and two original studies using new silicone PSD configurations to assess personal chemical exposures. For the first configuration, we designed the silicone pet tag for use on companion animals and demonstrated its use in a case-control study investigating feline hyperthyroidism. We determined that concentrations of the flame retardant tris(1,3-dichloro-2-isopropyl) phosphate (TDCIPP) were higher among pet tags worn by hyperthyroid compared to non-hyperthyroid cats, and we correlated TDCIPP pet tag concentrations with thyroid hormone levels in healthy cats. These results provided converging lines of evidence implicating TDCIPP flame retardant exposures as a risk factor for feline hyperthyroidism. For the second configuration, we developed the military-style silicone dog tag to wear around the neck and investigated occupational and non-occupational firefighter exposures to polycyclic aromatic hydrocarbons (PAHs), phthalates, and industrial-related chemicals. Of the 44 PAHs detected, this study was the first to identify personal firefighter exposures to 18 unique PAHs. We further determined that the dog tag concentrations were higher for the on- compared to off-duty samples and at the high compared to the low call volume fire department. PAH concentrations were strongly correlated with the number of fire attacks a firefighter participated in during the sampling period, compared to firefighter rank and years in the fire service. This suggested that quantitative data, rather than job descriptions and other surrogate data, should be employed for future firefighter chemical exposure assessments. This dissertation demonstrated that silicone wristbands and silicone PSDs can be applied to epidemiological studies to investigate the links between chemical exposures and adverse health outcomes

Determinants of pesticide concentrations in silicone wristbands worn by Latina adolescent girls in a California farmworker community: The COSECHA youth participatory action study

Personal exposure to pesticides has not been well characterized, especially among adolescents. We used silicone wristbands to assess pesticide exposure in 14 to 16 year old Latina girls (N = 97) living in the agricultural Salinas Valley, California, USA and enrolled in the COSECHA (CHAMACOS of Salinas Examining Chemicals in Homes and Agriculture) Study, a youth participatory action study in an agricultural region of California. We determined pesticide concentrations (ng/g/day) in silicone wristbands worn for one week using gas chromatography electron capture detection and employed gas chromatography mass spectrometry to determine the presence or absence of over 1500 chemicals. Predictors of pesticide detections and concentrations were identified using logistic regression, Wilcoxon rank sum tests, and Tobit regression models. The most frequently detected pesticides in wristbands were fipronil sulfide (87%), cypermethrin (56%), dichlorodiphenyldichloroethylene (DDE) (56%), dacthal (53%), and trans-permethrin (52%). Living within 100 m of active agricultural fields, having carpeting in the home, and having an exterminator treat the home in the past six months were associated with higher odds of detecting certain pesticides. Permethrin concentrations were lower for participants who cleaned their homes daily (GM: 1.9 vs. 6.8 ng/g/day, p = 0.01). In multivariable regression models, participants with doormats in the entryway of their home had lower concentrations (p < 0.05) of cypermethrin (87%), permethrin (99%), fipronil sulfide (69%) and DDE (75%). The results suggest that both nearby agricultural pesticide use and individual behaviors are associated with pesticide exposures