Purpose
Parathyroid hormone (PTH) concentrations are routinely measured in the diagnosis and management of bone and kidney diseases, but reference ranges can be overestimated if determined in ...otherwise healthy individuals for whom vitamin D deficiency was not evaluated. We establish PTH reference ranges in apparently healthy, normocalcemic, normophosphatemic individuals categorized by 25-hydroxyvitamin D (25(OH)D) status using the Elecsys
®
PTH (
cobas e
601) and Elecsys
®
Vitamin D total II electrochemiluminescence immunoassays (
cobas e
411).
Methods
This prospective, non-interventional study measured PTH in serum from 653 apparently healthy adults 56.7% female; 68.2% white/Caucasian; 28.6% African American; median age 44 years (range 21–83) from three diverse geographic sites across the USA during summer and winter months. Subjects were classified by concomitant vitamin D sufficiency (≥ 30 ng/mL), insufficiency (> 20 to < 30 ng/mL) or deficiency (≤ 20 ng/mL).
Results
In vitamin D sufficiency, median PTH was 31.9 pg/mL range (2.5th–97.5th percentile) 17.9–58.6 compared with 35.5 pg/mL (17.0–60.4) for insufficiency, and 39.8 pg/mL (19.5–86.4) for deficiency. A significant inverse relationship was found between PTH and 25(OH)D (
P
< 0.001). After accounting for vitamin D, potential effects of race or season as covariates were relatively small or absent.
Conclusions
Upper reference limits (URL) for PTH in vitamin D sufficiency/insufficiency were similar and lower than current values. Clinically important PTH elevations were observed in vitamin D deficiency, where revised reference ranges with a higher URL may be appropriate. These data may help to distinguish vitamin D-related PTH elevations from other causes e.g., primary (normocalcemic) or secondary hyperparathyroidism.
Purpose
To assess estradiol (E
2
) and progesterone levels during ovarian stimulation determined by third-generation (Gen III) and second-generation (Gen II) Elecsys
®
immunoassays.
Methods
E
2
and ...progesterone concentrations were measured using Elecsys
®
Gen III and Gen II immunoassays, and progesterone concentrations on the day of ovulation triggering were determined by LC–MS/MS. This was a retrospective, non-interventional study conducted at European tertiary referral infertility clinics in women aged 18–45 years, with a body mass index 18–35 kg/m
2
, regular menses, and both ovaries.
Results
Serum samples were obtained from 230 women classified by oocyte retrieval as poor (33.0%; 0–3 oocytes), normal (40.9%; 4–15 oocytes), or high (26.1%; > 15 oocytes) responders. E
2
and progesterone levels increased during ovarian stimulation, with greatest increases observed in high responders. Elecsys
®
Gen III and Gen II assay results were highly correlated for E
2
(Pearson’s
r
= 0.99) and progesterone (
r
= 0.89); Gen III results were lower than Gen II for both E
2
and progesterone. On the day of triggering, Gen III E
2
and progesterone levels showed a difference of − 15.0% and − 27.9%, respectively. Progesterone levels (on day of triggering) measured by LC–MS/MS correlated better with Gen III (0.98) than Gen II (0.90). Mean relative differences for Gen III and Gen II assays versus LC–MS/MS were 14.6% and 62.8%, respectively.
Conclusion
E
2
and progesterone levels determined with Elecsys
®
Gen II and III assays were highly correlated; results were lower for Gen III versus Gen II. Differences observed for progesterone on the day of triggering may be clinically relevant.
The article “EStradiol and PRogesterone in In vitro ferTilization (ESPRIT): a multicenter study evaluating third‑ versus second‑generation estradiol and progesterone immunoassays.
Both terrestrial and fresh or marine forces drive underground fluid flows in the coastal zone. Hydraulic gradients on land result in groundwater seepage near shore and may contribute to flows from ...confined aquifers further out on the shelf. The terrestrial and oceanic forces overlap spatially, so measured fluid advection through coastal sediments may be a result of composite forcing. “Subsurface/submarine groundwater discharge” (SGWD) can be defined as any and all flow of water on continental margins from the seabed to the coast, regardless of fluid composition or driving force. SGWD is typically characterized by low specific flow rates, making detection and quantification difficult. However, because such flows occur over very large areas, the total flux is significant. Discharging fluids, whether derived from land or composed of re-circulated seawater, will react with sediment components. These reactions may substantially increase the concentrations of nutrients, carbon, and metals in the fluids. These fluids are thus a source of biogeochemically important constituents to the coast. Terrestrially derived fluids represent a pathway for the flux of new material to the coast. This may result in diffuse pollution in areas where the discharge of contaminated groundwater occurs. This review presents an historical context of SGWD studies, defines the process in a form that is consistent with our current understanding of the driving forces as well as our assessment techniques, and reviews the estimated global fluxes and biogeochemical implications. This review concludes that, to fully characterize marine geochemical budgets, one must give due consideration to SGWD. New methodologies, technologies, and modeling approaches are required to discriminate among the various forces that drive SGWD, pollutants to evaluate these fluxes more precisely to Canadian coast.
In recent years global problems such as climatic change, acid rain, and water pollution in surface and subsurface environments dominate discussions of world environmental problems. In this paper, the ...roles of hydrologic processes and hydrogeochemical processes are investigated through development, modification, and application of mathematical models for addressing point and non-point source water quality modelling of receiving waters: surface water, subsurface water and lake water. The paper describes the use of models to simulate the movements of pollutants and water: subsurface water, surface water and lake sediments. A hydrological model was applied to Northeast Pond River watershed to understand climate change effects in the watershed. Four watershed acidification models were applied to compute hydrogen ion, alkalinity and sulphate concentrations from Turkey Lakes watershed, Canada. The computed hydrogen ion was used to estimate acidic events, magnitude of hydrogen ion, and duration using a stochastic model. There exist uncertainties in environmental models due to imperfect knowledge of processes controlling water quality parameters as well as errors in data. Monte Carlo, first order, and inverse method analyses were used to assess uncertainty in models. SUTRA (saturated–unsaturated transport) and SUTRA
−1 models were applied to Lambton county, Ontario, Canada to locate groundwater discharge areas for St. Clair River, calculate discharge rates, and hydrogeologic parameters. A sediment contamination model was developed and applied to Great Lakes sediment data to estimate transport parameters by
210Pb data. It was then coupled with fatty acid data and results were compared with observed data. A contaminant transport model was developed and applied to two North American streams to compute stream water concentration. The computed data was compared with observed data using a simple statistical method. A hydrological model was coupled with water quality models and RAISON (regional analysis by intelligent systems on) expert system and applied to Canadian watersheds. Digital satellite data was used to locate groundwater discharge and recharge areas in the watershed. This data is useful as observed data for hydrological modelling and GIS (Geographical Information System) system.
The effects of human activities and sea-level changes on the spatial and temporal behaviour of the coupled mechanism of salt-water and freshwater flow through the Godavari Delta of India were ...analysed. The density driven salt-water intrusion process was simulated with the use of a SUTRA (Saturated-Unsaturated TRAnsport) model. Physical parameters, initial heads, and boundary conditions of the delta were defined on the basis of available field data, and an areal, steady-state groundwater model was constructed to calibrate the observed head values corresponding to the initial development phase of the aquifer. Initial and boundary conditions determined from the areal calibration were used to evaluate steady-state, hydraulic heads. Consequently, the initial position of the hydraulic head distribution was calibrated under steady-state conditions. The changes of initial hydraulic distribution, under discharge and recharge conditions, were calculated, and the present-day position of the interface was predicted. The present-day distribution of hydraulic head was estimated via a 20-year simulation. The results indicate that a considerable advance in seawater intrusion can be expected in the coastal aquifer if current rates of groundwater exploitation continue and an important part of the freshwater from the river is channelled from the reservoir for irrigation, industrial and domestic purposes.
The synthesis and photophysical characterisation are reported of a series of cationic, neutral and anionic europium and terbium complexes based on structurally related, nonadentate ligands based on ...the cyclen macrocycle. Each complex incorporates a tetraazatriphenylene moiety and overall absolute emission quantum yields are in the range 15-40% in aerated aqueous media. Dynamic quenching of the lanthanide excited state occurs with electron-rich donors, e.g. iodide, ascorbate and urate, and a mechanistic interpretation is put forward involving an electron transfer process. The cationic lanthanide complexes are taken up by NlH/3T3 cells and tend to localise inside the cell nucleus.
The interaction of q = 0 delta- and lambda-Tb and Eu complexes with poly(dAdT), poly(dGdC) and calf-thymus DNA has been examined by absorption, emission and chiroptical spectroscopy and is sensitive ...to complex helicity, base-pair type and the nature of the lanthanide excited state.
Abstract
The
1
H and
17
O NMR relaxometric properties of two cationic complexes formed by Gd
III
with a macrocyclic heptadentate triamide ligand, L
1
, and its Nmethylated analogue, L
2
, have been ...investigated in aqueous media as a function of pH, temperature and magnetic field strength. The complexes possess two water molecules in their inner coordination sphere for which the rate of exchange has been found to be sensibly faster for the Nmethylated derivative and explained in terms of electronic effects (decrease of the charge density at the metal center) and perturbation of the network of hydrogen‐bonded water molecules in the outer hydration sphere. The proton relaxivity shows a marked dependence from pH and decreases of about six units in the pH range 6.5 to 9.0. This has been accounted for by the displacement of the two water molecules by dissolved carbonate which acts as a chelating anion. The formation of ternary complexes with lactate, malonate, citrate, acetate, fluoride and hydrogenphosphate has been monitored by
1
H NMR relaxometric titrations at 20 MHz and pH 6.3 and the value of the affinity constant,
K
, and of the relaxivity of the adducts could be obtained. Lactate, malonate and citrate interact strongly with the complexes (log
K
≥3.7) and coordinate in a bidendate mode by displacing both water molecules. Larger affinity constants have been measured for GdL
2
. Acetate, fluoride and hydrogenphosphate form monoaqua ternary complexes which were investigated in detail with regard to their relaxometric properties. The NMR dispersion (NMRD) profiles indicate a large contribution to the relaxivity of the adducts from water molecules belonging to the second hydration shell of the complexes and hydrogen‐bonded to the anion. A VT
17
O NMR study has shown a marked increase of the rate of water exchange upon binding which is explained by coordination of the anion in an equatorial site, thus leaving the water molecule in an apical position, more accessible for interactions with the solvent molecules of the second hydration shell which facilitate the exchange process.
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