The 1-31 fragment of human PTH [hPTH-(1-31)NH2] has been shown, like hPTH-(1-34), to have anabolic effects on the skeletons of ovariectomized rats when given intermittently, but, unlike hPTH-(1-34), it does so without affecting serum calcium concentrations and does not activate the protein kinase C second messenger pathway in some target cells. To investigate the biochemical responses to hPTH-(1-31) in humans, we have directly compared it to hPTH-(1-34) during the course of slow infusions of each. Ten healthy adults, five men and five women, aged 26+/-5 yr (range, 22-37), each received 8-h continuous infusions of 8 pmol/kg.h hPTH-(1-34) and hPTH-(1-31) given in random order at least 2 weeks apart. During the infusions there were significant increases in both plasma and urinary cAMP (P < 0.05), but there were no differences in the responses between the two peptides (P = 0.362 for plasma; P = 0.987 for urine). There were also significant phosphaturic and natriuretic responses to the two peptides, which again were not different between peptides. During the infusion of hPTH-(1-34) serum ionized calcium (Ca2+) increased from 1.21+/-0.033 to 1.29+/-0.046 mmol/L (P < 0.01), and endogenous hPTH-(1-84) decreased from 29.6+/-9 to 15.0+/-5.7 pg/mL (P < 0.01), such that there was a negative correlation between them (r2 = 0.45). However, when hPTH-(1-31) was infused, neither serum Ca2+ (1.24+/-0.03 vs. 1.25+/-0.03) nor hPTH-(1-84) (26.8+/-5 vs. 30.7+/-12 pg/mL) was affected. Circulating concentrations of 1,25-dihydroxyvitamin D3 increased from 92+/-42 to 131+/-63 pmol/L (P < 0.05) during infusion of hPTH-(1-34) and from 92+/-27 to 110+/-42 pmol/L (P = NS) during hPTH-(1-31) infusion. There was also a significant increase in the urinary measure of type I collagen degradation of aminoterminal telopeptides from 78+/-45 to 101+/-51 nmol/mmol creatinine (P < 0.05) when hPTH-(1-34) was infused, but it was not affected (68+/-30 vs. 66+/-24 nmol/mmol creatinine) by hPTH-(1-31). Therefore, hPTH-(1-31) appears to be equivalent and equipotent to hPTH-(1-34) in the release of cAMP from target tissues and the renal handling of phosphate and sodium. However, at the doses employed, it does not increase serum calcium, is a weaker stimulator of the 25-hydroxyvitamin D-1alpha-hydroxylase, and does not induce rapid bone resorption.

Background: Indigenous communities in Canada and the US are disproportionately exposed to contaminated sites, often arising from industrial and waste disposal activities. For instance, ~34% of US EPA Superfund sites are of Native American interest, and ~29% of Canadian federal contaminated sites are on Indigenous reserve land. Contaminated sites pose unique challenges to many Indigenous peoples who consider the land as an integral part of food systems, culture, and the economy. Federal management of contaminated sites is challenged by epistemological differences, regulatory barriers, and minimal scientific research. Objectives: This scoping review aimed to identify and map information on contaminated sites and Indigenous peoples in Canada and the US, namely: 1) the relationship between contaminated sites and Indigenous people, and their land and food systems; 2) strategies, challenges, and successes for contaminated sites assessment and management on Indigenous land; and 3) Indigenous leadership and inclusion in contaminated site assessment and management. Methods: Three streams of data were retrieved from January to March 2022: a systematic literature search (key word groups: Indigenous people and contaminated sites); a grey literature search; and an analysis of federal contaminated site data (Canadian Federal Contaminated Sites Inventory and US EPA Superfund Database). Results: Our search yielded 49 peer-reviewed articles, 20 pieces of grey literature, and 8114 federal site records (1236 Superfund, 6878 FCSI), evidencing the contamination of the lands of 815 distinct Indigenous tribes and nations and the presence of 440 different contaminants or contaminant groups. Minimal information is available on the potential health and ecological effects, assessment and management of risks, and collaboration on contaminated site processes relative to the number of sites on or adjacent to Indigenous lands. Discussion: By integrating three diverse data streams we discovered a multi-disciplinary yet disparate body of information. The results point to a need to prioritize holism, efficiency, and Indigenous leadership in contaminated site assessment, management, and research. This should include a focus on community-specific approaches to site assessment and management; a re-conceptualization of risks related to sites that privileges Indigenous epistemologies; greater collaboration between networks such as the scientific community, Indigenous communities, and federal governments; and a re-evaluation of current management frameworks with Indigenous leadership at the forefront.

Parental preconception exposures to built and natural outdoor environments could influence pregnancy and birth outcomes either directly, or via a range of health-related behaviours and conditions. However, there is no existing review summarising the evidence linking natural and built characteristics, such as air and noise pollution, walkability, greenness with pregnancy and birth outcomes. Therefore, the planned scoping review aims to collate and map the published literature on parental preconception exposures to built and natural outdoor environments and adverse pregnancy and birth outcomes. We will search electronic databases (MEDLINE, EMBASE, Scopus) to identify studies for inclusion. Studies will be included if they empirically assess the relationship between maternal and paternal preconception exposures to physical natural and built environment features that occur outdoors in the residential neighbourhood and adverse pregnancy and birth outcomes. Two reviewers will independently screen titles and abstracts, and then the full text. Data extraction and assessment of study quality will be performed by one researcher and checked by a second researcher. Results will be summarised in a narrative synthesis, with additional summaries presented as tables and figures. The scoping review will be disseminated via a peer-reviewed publication, at academic conferences, and published on a website.