An observational cohort study on antimicrobial usage on dairy farms in Quebec, Canada.

Quantification of antimicrobial usage (AMU) is crucial to measure the effect of intervention programs, to determine associations between usage and resistance, to compare populations, and for benchmarking purposes. The primary objective of the study was to describe quantitatively the AMU on Quebec dairy farms over 1 yr: (1) the total AMU, (2) the AMU per administration route (intramammary, injectable, oral, intrauterine), and (3) the AMU per antimicrobial class and according to the categorizations of Health Canada and the World Health Organization. The secondary objective was to assess the effect of several characteristics (herd size, level of milk production, and incidence rate of common infectious diseases) on AMU rate. The AMU data were obtained for 101 dairy farms randomly selected in 3 important Quebec dairy regions by collecting and recording all empty drug packaging and invoices for medicated feed (spring 2017 to spring 2018). The AMU rate was reported in number of Canadian defined course doses for cattle per 100 cow-years. The average herd size was 67 cows per farm, and 2/101 farms were certified organic. Overall, an estimated mean of 537 Canadian defined course doses for cattle/100 cow-years was observed. The intramammary route during lactation was the most frequently observed, followed, in decreasing order of usage, by oral route in the feed, intramammary route at drying-off, and injectable route. Oral (other than in animal feed) and intrauterine formulations were infrequently collected from the garbage cans. The 5 most frequently observed antimicrobial classes were, by decreasing order of usage, ionophores, penicillins, aminocoumarins, aminoglycosides, and polymyxins. Highest priority critically important antimicrobials as defined by the World Health Organization were mainly collected from intramammary formulations during lactation followed by injectable and drying-off intramammary formulations. The herd size was positively associated with the total AMU rate but not with the usage rate of highest priority critically important antimicrobials. Incidence of diseases along with preventive use of antimicrobials (drying-off and medicated feed with antimicrobials) explained 48% of the variance in total AMU rate.

Colonization pressure as a risk factor of ICU-acquired multidrug resistant bacteria: a prospective observational study.

The primary objective of this study was to evaluate the impact of colonization pressure on intensive care unit (ICU)-acquired multidrug resistant bacteria (MDRB). All patients hospitalized for more than 48 h in the ICU were included in this prospective observational study. MDRB were defined as methicillin resistant Staphylococcus aureus, Pseudomonas aeruginosa resistant to ceftazidime or imipenem, Gram-negative bacilli producing extended-spectrum beta-lactamases (ESBL), and all strains of Acinetobacter baumannii and Stenotrophomonas maltophilia. Colonization pressure was daily calculated in the three participating ICUs. Univariate and multivariate analyses were used to determine risk factors for ICU-acquired MDRB. Two hundreds and four (34%) of the 593 included patients acquired an MDRB during their ICU stay. Multivariate analysis identified colonization pressure as an independent risk factor for ICU-acquired MDRB (OR (95% CI) 4.18 (1.03-17.01), p = 0.046). Other independent risk factors for ICU-acquired MDRB were mechanical ventilation (3.08 (1.28-7.38), p = 0.012), and arterial catheter use (OR, 3.04 (1.38-6.68), p = 0.006). ICU-acquired MDRB were associated with increased mortality, duration of mechanical ventilation, and ICU stay. However, ICU-acquired MDRB was not independently associated with ICU-mortality. Colonization pressure is an independent risk factor for acquiring MDRB in the ICU.

Screening for pre-eclampsia early in pregnancy: performance of a multivariable model combining clinical characteristics and biochemical markers.

OBJECTIVE: To investigate the performance of a multivariable model combining a priori clinical characteristics and biomarkers to detect, early in pregnancy, women at higher risk of developing pre-eclampsia (PE). DESIGN: Nested case-control study. SETTING: University medical centre, Quebec, Canada (CHU de Québec). POPULATION: A total of 7929 pregnant women recruited between 10 and 18 weeks of gestation. In all, 350 developed hypertensive disorders of pregnancy (HDP)-of which 139 had PE, comprising 68 with severe PE and 47 with preterm PE-and were matched with two women with a normal pregnancy. METHODS: We selected a priori clinical characteristics and promising markers to create multivariable logistic regression models: body mass index (BMI), mean arterial pressure (MAP), placental growth factor, soluble Fms-like tyrosine kinase-1, pregnancy-associated plasma protein A and inhibin A. MAIN OUTCOME MEASURES: PE, severe PE, preterm PE, HDP. RESULTS: At false-positive rates of 5 and 10%, the estimated detection rates were between 15% (5-29%) and 32% (25-39%), and between 39% (19-59%) and 50% (34-66%), respectively. Considering the low prevalence of PE in this population, the positive predictive values were 7% (5-9%) to 10% (7-13%) for PE and 2% (1-4%) to 4% (3-6%) in the preterm and severe PE subgroups. The multivariable model yielded areas under the receiver operating characteristics curves (AUC) between 0.72 (0.61-0.81) and 0.78 (0.68-0.88). When only BMI and MAP were included in the model, the AUC were similar to those of the a priori model. CONCLUSIONS: In a population with a low prevalence of preterm PE, a multivariable risk algorithm using an a priori combination of clinical characteristics and biochemical markers did not reach a performance justifying clinical implementation as screening test early in pregnancy.

Co-designing a Canadian adaptation of a lifestyle-oriented intervention aimed to improve daily functioning of individuals living with chronic pain: a multi-method study protocol of REVEAL(OT) Canada.

Background: Living with chronic pain (CP) often implies major lifestyle changes, including modifications of daily routines and work. Surprisingly, few validated and effective interventions specifically target functional outcomes in this population. Redesign your Everyday Activities and Lifestyle with Occupational Therapy [REVEAL(OT)] is a lifestyle-oriented intervention led by occupational therapists that directly targets the daily functional challenges of living with CP. The intervention was initially developed and studied as an add-on to standard treatment delivered by Danish multidisciplinary specialized pain clinics. Adapting, implementing, and evaluating REVEAL(OT) within the Canadian healthcare system will contribute to broadening the scope of treatments offered in specialized pain clinics that do not yet include occupational therapy. Objective: The proposed study aims to define and refine REVEAL(OT)/CA with partners (authors of original intervention, people with lived experience, clinicians, managers). Methods: This participatory action research will use a multi-method design and follow the ORBIT model for developing behavioral treatments for chronic diseases. A process of co-construction with partners and an advisory committee will take place in two Montreal specialized pain clinics. It consists of two related work packages (WPs). In WP1, a first series of focus groups with partners (n = 86) and workshops with the advisory committee will be conducted to co-develop the hypothetical pathway describing intervention components and their potential mechanisms of action on targeted outcomes, as well as the first version of the adapted intervention manual. WP2 will co-refine REVEAL(OT)/CA by exploring its acceptability, feasibility and mechanisms of action through intervention deliveries (at least twice in each of two specialized pain clinics; n ≥ 60 patients) and focus groups and/or individual interviews with participating patients and partners. At the end of this study, the intervention manual will be generated both in French and English. Discussion: This study will set the stage for subsequent implementation and effectiveness assessment projects and be an important step towards the deployment of interventions aiming to improve engagement in meaningful daily activities among adults living with CP. Registration: OSF Registries, osf.io/8gksa. Registered 3 August 2023, https://osf.io/8gksa.

Pilot Study of French-Canadian Lifestyle Redesign® for Chronic Pain Management.

As chronic pain (CP) interferes with an individual's lifestyle by limiting meaningful activities and health-related quality of life (HRQoL), occupational therapy (OT) plays an important role in CP management interventions. This pilot study aimed to explore the influence of a 13-week French-Canadian Lifestyle Redesign® for CP. A mixed-methods research design including a preexperimental quantitative component pre-/posttest was used with 15 participants with fibromyalgia. Although pain remained unchanged after the intervention, improvements were observed in participants' engagement in meaningful activities (p < .01), life balance (p < .01), mental components of HRQoL (p < .01), depressive symptoms (p = .047), and pain self-efficacy (p < .01). After the intervention, phone interviews (n = 6) highlighted the participants' appreciation of the focus being placed on their daily routines and the development of a sense of belonging throughout the intervention. This study suggests the potential feasibility and benefits of an occupation-based approach in CP management.

Review: Climate Finance readiness of the animal protein sector: overview of experience in linking the sector to Climate Finance, and options to address bottlenecks.

Despite the importance of the role of Climate Finance to comply with the United Nations Framework Convention on Climate Change 1.5°C objective, there is no consensus on the definition of Climate Finance and the estimated assessment of its aggregated flows and effects remains challenging. Despite being a major emitter and having a significant and cost-effective mitigation potential, the livestock sector has so far only received a marginal share of Climate Finance. As demand for animal protein products continues to increase (68% between 2010 and 2050), there is a compelling case for channeling more Climate Finance investments into the sector to incentivize greenhouse gas emissions reduction at scale. Bottlenecks in linking the livestock sector to Climate Finance include the insufficient capacity to assess the cost-benefit of projects, high upfront cost and risk perception of investors, the informality of the sector, non-existence of Climate Finance instruments dedicated to the livestock sector and lack of cost-efficient Monitoring, Reporting and Verification systems. Nevertheless, recent developments provide avenues to increase the access of the animal protein sector to Climate Finance.

Data on soil physicochemical properties and chemical composition of rainfall and of throughfall and stemflow generated by Turkey oak trees (Quercus cerris L.) in acid and sub-alkaline soils.

We report data on the physicochemical properties of soils collected in two adjacent areas, one acid and one sub-alkaline, both developed on sequential beds of Plio-pleistocene marine sediments, and on the chemical composition of ecological solutions (rainfall, throughfall and stemflow) separately collected in the two areas. Throughfall and stemflow were generated by Turkey oak trees (Quercus cerris L.), which was the dominant tree species in both study areas. These data are related to the original article "Soil affects throughfall and stemflow under Turkey oak (Quercus cerris L.)" (Corti et al., 2019) [1].

Uptake of plasma fibrinogen into the alpha granules of human megakaryocytes and platelets.

The origin of platelet alpha-granule fibrinogen (Fg), whether from endogeneous synthesis or exogeneous derivation, remains unknown. Although Fg biosynthesis by megakaryocytes (MK) has been suggested, recent studies have demonstrated that certain alpha-granular proteins originate primarily from plasma. To study the origin of alpha-granule Fg, platelet-associated Fg was measured by ELISA and Western blotting, and localized by immunofluorescence and immunoelectron microscopy in a patient with symptomatic congenital afibrinogenemia before and after replacement therapy with cryoprecipitate. alpha-Granule Fg was detected in the majority of platelets as early as 24 h postinfusion, suggesting that direct platelet uptake was occurring. Platelet Fg reached a maximum value of 42.5% of normal values at 3 d postinfusion and was localized in the alpha-granules, while plasma levels followed a typical half-life profile. Significant alpha-granule Fg was still detectable at 13 d postinfusion, with plasma Fg virtually absent. Studies on cultured CFU-MKs from the patient also confirmed that MKs can incorporate exogeneous Fg into alpha-granules. These results indicate that platelet alpha-granule Fg can be derived from the circulating plasma pool and that Fg uptake can occur in both platelets and MKs.

Lentivirus degradation and DC-SIGN expression by human platelets and megakaryocytes.

BACKGROUND AND AIM: As platelets are able to endocytose human immunodeficiency virus (HIV), we have investigated the fate of lentiviruses when endocytosed by human platelets and megakaryocytes (MK), and have characterized a specific receptor directly involved in this function. METHODS: Genetically modified (non-replicative) lentiviruses with an HIV envelope (HIV-e) or with a vesicular stomatitis virus protein G envelope (VSV-e) were alternatively used and their interaction with platelets and MK analyzed by electron microscopy (EM) and immunoEM. RESULTS: When incubated with platelets, HIV-e and VSV-e lentiviruses were internalized in specific endocytic vesicles and trafficked to the surface connected canalicular system (SCCS). Double immunolabeling for the viral P24 core protein and alpha-granule markers showed that lentiviruses were degraded in the SCCS after contact with alpha-granule proteins. In culture MK, lentiviruses were found in endocytic vesicles and accumulated in acid phosphatase-containing multivesicular bodies (MVB). The expression of the pathogen receptor dendritic cell-specific ICAM-grabbing non-integrin (DC-SIGN) was then demonstrated in platelets by flow cytometry, immunoEM and Western blot. Anti-DC-SIGN antibodies decreased HIV-e lentivirus internalization by platelets, showing that the receptor is functional. Specific signals for DC-SIGN protein and mRNA were also found in MK. CONCLUSION: This study indicates that platelets and MK can internalize lentiviruses in a pathway, which either provide a shelter to lentiviral particles or alternatively disrupts viral integrity. The receptor DC-SIGN is involved in this function.

Calcineurin links Ca2+ dysregulation with brain aging.

Brain aging is associated with altered Ca(2+) regulation. However, many Ca(2+) signal transduction mechanisms have not been explored in the aged brain. Here, we report that cytosolic expression and activity of the Ca(2+)-dependent protein phosphatase calcineurin (CaN) increases in the hippocampus during aging. CaN changes were paralleled by increased activation, but not expression, of CaN-regulated protein phosphatase 1 and a reduction in the phosphorylation state of CaN substrates involved in cell survival (i.e., Bcl-2-associated death protein and cAMP response element-binding protein). The age-related increase in CaN activity was not attributable to the inability of CaN to translocate to the membrane and was reduced by blocking L-type Ca(2+) channels. Finally, increased CaN activity correlated with memory function as measured with the Morris water escape task. The results suggest that altered regulation of CaN is one of the processes that could link Ca(2+) dyshomeostasis to age-related changes in neural function and cognition.

Molecular study of the hematopoietic zinc finger gene in three unrelated families with gray platelet syndrome.

Hematopoietic zinc finger (HZF) null mice have features reminiscent of patients with gray platelet syndrome (GPS), a rare inherited bleeding disorder. This similarity has suggested that HZF deregulation might be involved in the human disease. The sequence of the eight exons of the HZF gene as well as the study of its expression in blood samples from five patients belonging to three different families did not reveal any modifications when compared with healthy donors. This study indicates that HZF is unlikely to be responsible for GPS.

The expression of prion protein (PrP(C)) in the megakaryocyte lineage.

BACKGROUND: Cellular prion protein (PrP(C)) is a naturally occurring protein in normal individuals which adopts an abnormal conformation, termed scrapie prion protein (PrP(Sc)) that is associated with disease. There is great concern that clinically asymptomatic variant Creutzfeldt-Jacob disease (vCJD) may transmit PrP(Sc) in blood transfusion products. PrP(C) is widely expressed and has been found in human blood. The majority of cellular borne PrP(C) is associated with platelets (84%). Although PrP(C) mRNA has been demonstrated in platelets, the quantity is unknown and may not reflect the total PrP(C) present. OBJECTIVE: To investigate the expression of PrP(C) in the megakaryocyte lineage. METHODS: The expression of PrP(C) was studied in CD34+ cells, cultured megakaryocytes and platelets using electron microscopy, flow cytometry, semi-quantitative RT-PCR and immunofluorescence confocal microscopy. RESULTS AND CONCLUSIONS: The expression of PrP(C) appeared to increase with differentiation and polyploidization in the megakaryocyte lineage. PrP(C) was located within platelet alpha-granules and its source is likely to be from megakaryocyte precursors. If PrP(Sc) has a similar distribution, these results have implications for the selection of blood donors and preparation of cell-depleted blood products.

Multicenter evaluation of the Glucometer Elite XL meter, an instrument specifically designed for use with neonates.

OBJECTIVE: To evaluate the clinical performance of the Glucometer Elite XL Diabetes Care System in neonatal settings using a multicenter study RESEARCH DESIGN AND METHODS: A total of 388 blood specimens from 333 neonates were included in the study. A capillary or arterial sample was analyzed for determination of glucose with the Glucometer Elite XL system by an attending trained nurse. Through the same sampling site, a specimen was collected and sent to the laboratory for measurement of plasma glucose, bilirubin, and hematocrit. RESULTS: The regression analysis between the results of the Glucometer Elite XL system and comparative methods resulted in the following: Glucometer Elite XL meter = 1.01 x laboratory method + 0.02 mmol/l (n = 388). For the 1.1-4.0 mmol/l plasma glucose range, the regression was Glucometer Elite XL meter = 1.07 x laboratory method + 0.12 mmol/l (n = 150). A difference plot indicated a mean bias of 0.04 mmol/l (95% CI -0.01 to 0.10). No relationship was found between meter glucose biases and hematocrit levels (r = 0.10, P = 0.14). Although a statistically significant correlation existed between bilirubin levels and the glucose meter biases (r = 0.14, P = 0.005), the predicted mean biases were of little clinical significance. CONCLUSIONS: The Glucometer Elite XL system showed a good performance when used in neonatal settings.

Of mice and men: comparison of the ultrastructure of megakaryocytes and platelets.

OBJECTIVE: Mice provide an excellent model for studying platelet and megakaryocyte (Mk) biology in vivo. Given the increasing use of transgenic and knockout mice, it is important that any similarities and differences between murine and human platelet/Mk biology be well defined. Therefore the objective of this study was to compare and contrast in detail any significant morphological differences between Mks, platelets, and mechanisms of thrombopoiesis in humans and mice. METHODS: The distinctive structural and ultrastructural features of murine and human platelets and Mks are reviewed. Several platelet and Mk glycoproteins were also localized in murine cells by immunoelectron microscopy using polyclonal antibodies directed against human platelet proteins and compared to existing human data. Finally, the ultrastructure of maturing murine and human Mks in culture and bone marrow were examined in detail to facilitate a comparison of either in vivo or in vitro platelet production. RESULTS: Human and murine platelets exhibit significant but well-established morphological differences. Murine platelets are smaller and more numerous and display much greater granule heterogeneity than their human counterparts. Immunoelectron microscopy also demonstrated that murine platelet alpha-granules are highly compartmentalized. In fact, they are remarkably similar to human alpha-granules, with asymmetrical distribution of von Willebrand factor (vWF), and labeling of alpha(IIb)beta(3) and P-selectin (CD62P) in the granule limiting membrane. In vivo, murine but not human Mks are also consistently localized within the spleen. Subcellular events accompanying platelet formation and release by murine Mks are presented for the first time, and compared to human. Consistent differences were found in the pathway of redistribution of demarcation membranes preceding platelet formation, which may be important for the clarification of the mechanism of platelet release. CONCLUSION: Human and murine platelets and Mks display several characteristic ultrastructural differences (size, number, histological distribution, platelet shedding) which have been emphasized and analyzed in this report. Nevertheless, since there are also many close similarities (organelle and glycoprotein subcellular distribution) mice offer an excellent in vivo model to study various aspects of human Mk and platelet biology.

Nitric oxide-dependent and independent effects on human platelets treated with peroxynitrite.

OBJECTIVE: Peroxynitrite (ONOO-) is an oxidant formed from the rapid reaction of superoxide and nitric oxide (NO) at sites of inflammation. The literature reports conflicting data on the effects of ONOO- in biological systems, with both NO- and oxidant-dependent effects having been demonstrated. The aim of this study was to investigate these distinct mechanisms through examining molecular aspects of the effects of ONOO- on human platelets, a system in which we have previously shown that ONOO- has both pro- and anti-aggregatory effects. METHODS: Platelet function was assessed by measuring platelet P-selectin expression flow cytometrically, intraplatelet Ca2+ concentrations, and by light aggregometry. A colorimetric method was used to measure extracellular platelet membrane thiols. The contribution of NO and cGMP to the pharmacological effects of ONOO- was investigated using an inhibitor of the soluble guanylate cyclase (sGC), 1H-[1,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one (ODQ), and the NO scavenger oxy-haemoglobin. RESULTS: Peroxynitrite (50-400 microM) caused a concentration-dependent increase in the number of platelets expressing P-selectin, an increase in intraplatelet Ca2+ concentrations and a decrease in platelet membrane thiols. Peroxynitrite-induced P-selectin expression was augmented by ODQ. In contrast, when P-selectin expression was elicited by collagen, ONOO- acted as an inhibitor of this process, an effect that was further enhanced by the addition of 1% plasma, ODQ or oxy-haemoglobin abolished this inhibitory effect. Finally, low concentrations (50-100 microM) of ONOO- inhibited collagen-induced platelet aggregation, an effect that was reversed by oxy-haemoglobin. CONCLUSIONS: Peroxynitrite exerts dual effects on platelets, which are either activating or inhibitory due to the conversion of ONOO- to NO or NO donors. Peroxynitrite-induced platelet activation seems to be due to thiol oxidation and an increase in intracellular Ca2+. It is important to note that inhibitory, NO-dependent effects occur at lower concentrations than the activating effects. These data are then consistent with the conflicting literature, showing both damaging and cytoprotective effects of ONOO- in biological systems. We hypothesize that the conversion of ONOO- to NO is the critical factor determining the outcome of ONOO- exposure in vivo.

The P-selectin cytoplasmic domain directs the cellular storage of a recombinant chimeric factor IX.

Hemophilia B was recognized as a good candidate for gene therapy. Several strategies have been attempted and gave promising results in hemophilic animals but failed to achieve corrective levels in humans. To overcome this inconvenience we aimed to generate intracellular pools of factor (F)IX in cells that are implicated in the hemostatic response, e.g. endothelial cells and platelets. Upon stimulation, these cells release their granule content, which in this case would result in an increase in local FIX concentration, and could locally produce an effective hemostasis. In an attempt to produce an intracellular pool of releasable coagulation FIX, the cytoplasmic domain of the P-selectin (pselCT) molecule was fused to the carboxy-terminal extremity of the human FIX protein. The properties of this chimeric molecule (FIX-pselCT) were studied in AtT20, a cell line which possesses storage granules. As previously shown for transmembrane molecules but not for a soluble protein such as FIX, the pselCT fragment induces the storage of FIX-pselCT. The coagulant activity of FIX-pselCT was not affected by the addition of the pselCT tail. The treatment of AtT20 cells with different inhibitors revealed that FIX-pselCT was not submitted to intracellular degradation and that the half-life of the chimeric molecule was at least two times longer than that of FIX-WT. An immunoelectron microscopic analysis demonstrated a specific localization of FIX-pselCT within the ACTH-containing granules. Cell stimulation using Phorbol Myristrate Acetate (PMA), ionophore A-23187 or 8-Br-cAMP induced efficient release of an active FIX-pselCT. These data demonstrate that the addition of the cytoplasmic domain of P-selectin to FIX modifies the cellular fate of the FIX molecule by directing the recombinant protein toward regulated-secretory granules without altering its coagulant activity.

Three months of chronic ethanol administration and the behavioral outcome of rats after lateral fluid percussion brain injury.

This study examined the effects of 3 months of chronic ethanol administration (CEAn) on the behavioral outcome in rats after lateral fluid percussion (FP) brain injury. Rats were given either an ethanol liquid diet (ethanol diet groups) or a pair-fed isocaloric sucrose control diet (control diet groups) for 3 months. Then, rats from both diet groups were subjected to either lateral FP brain injury of moderate severity (1.8 atm) or to sham operation. Postinjury behavioral measurements revealed that brain injury caused significant spatial learning disability in both diet groups. There were no significant differences in spatial learning ability in the sham or brain-injured animals between the control and ethanol diets. However, a trend towards cognitive impairment in the sham animals and a trend towards reduced deficits in the brain-injured animals were observed in the ethanol diet group. Histologic analysis of injured animals from both diet groups revealed similar extents of ipsilateral cortical and hippocampal CA3 damage. These results, in general, suggest that 3 months of CEAn does not significantly alter the behavioral and morphologic outcome of experimental brain injury.

Microalbumin as a marker of premature delivery.

OBJECTIVE: To determine if microalbumin excretion can predict the development of premature delivery. METHODS: The possibility of predicting, early in pregnancy, the development of a preterm delivery using urinary albumin was investigated in 1422 nulliparous women recruited prospectively. A first morning urine sample was collected at three occasions during pregnancy (8-14, 15-24, 25-34 weeks' gestation) for the determination of urinary albumin excretion. RESULTS: No significant correlation was found between gestational age and urinary albumin (absolute concentration, albumin-creatinine ratio, or relative clearance of albumin) at either visit (r ranging from -0.043 to 0.036; P > .1). The incidence of preterm birth was similar for the first and fourth quartiles of the urinary albumin-creatine ratio for the second visit (5.8 and 5.7%, respectively). CONCLUSION: Urinary albumin is not a useful marker of preterm birth in a low-risk general population.

Platelet angiotensin II binding sites and early detection of preeclampsia.

OBJECTIVE: To determine if platelet angiotensin II binding density during the second or third trimester of pregnancy can be used as a marker for early detection of women who will develop preeclampsia. METHODS: We collected blood samples from 412 nulliparous pregnant women during their second or third trimesters. They were classified in four groups after delivery: normotensive (n=297), transient hypertensive (n=54), preeclamptic (n=39), and chronic hypertensive (n=22). We also studied 35 nonpregnant women and 122 women in the peripartum period. The binding capacity of platelet angiotensin II receptors was analyzed in each patient. RESULTS: In normotensive pregnancies, there was a significant decrease in mean (+/-standard error of the mean [SEM]) platelet binding in the second trimester (1.6+/-0.2 fmol/10(9) cells) compared with nonpregnant women (3.3+/-0.7 fmol/10[9] cells). No statistical differences were observed in the mean (+/-SEM) number of platelet angiotensin II binding sites between the groups studied in the third trimester (normal: 1.7+/-0.1 fmol/10(9) cells; transient hypertensive: 2.3+/-0.4 fmol/10(9) cells; preeclamptic: 1.6+/-0.4 fmol/10(9) cells, and chronic hypertensive: 1.6+/-0.6 fmol/10(9) cells), nor were any significant differences found in second-trimester values. At cutoff levels providing identical sensitivities, angiotensin II binding showed significantly lower positive predictive values than mean arterial pressure (P < .05). With this study's sample size, we could have demonstrated an improvement in positive predictive values of 20% with a statistical power (1-beta) of 90%. CONCLUSION: The measurement of platelet angiotensin II receptor density cannot be recommended for the early detection of preeclampsia.

HCCCH experiment for through-bond correlation of thymine resonances in 13C-labeled DNA oligonucleotides.

Application of heteronuclear magnetic resonance pulse methods to 13C, 15N-labeled nucleic acids is important for the accurate structure determination of larger RNA and DNA oligonucleotides and protein-nucleic acid complexes. These methods have been applied primarily to RNA, due to the availability of labeled samples. The two major differences between DNA and RNA are at the C2' of the ribose and deoxyribose and the additional methyl group on thymine versus uracil. We have enzymatically synthesized a 13C,15N-labeled 32 base DNA oligonucleotide that folds to form an intramolecular triplex. We present two- and three-dimensional versions of a new HCCCH-TOCSY experiment that provides intraresidue correlation between the thymine H6 and methyl resonances via the intervening carbons (H6-C6-C5-Cme-Hme).