Delayed efficient anticoagulation with heparin in patients with a weight of 110 kg and more treated for acute coronary syndrome.

OBJECTIVE: The use of a weight-based nomogram is considered as standard care for prescribing appropriate doses of unfractionated heparin (UFH). Because of the need for multiple other medications that may affect bleeding and that clinical data have relied on similar dosing algorithms, maximum initial bolus and infusion rates have been suggested (capped initial dose). Whether these weight-based heparin nomograms properly address therapeutic dosing in obese patients remains questionable. DESIGN AND METHODS: Thirty patients treated for acute coronary syndrome and weighing ≥110 kg were retrospectively compared with 90 controls (three groups of 30 patients, weighting 50-69.9, 70-89.9, or 90-109.9 kg), all treated with UFH, July 2008 to April 2009. The primary end point was the time required to obtain a threshold activated partial thromboplastin time (aPTT). RESULTS: Mean time to achieve threshold aPTT was longer for obese patients weighing ≥110 kg than for controls (31.47 vs. 12.89 hours; P < 0.0001). At 24 hours, 63% of obese patients weighing ≥110 kg had not reached threshold aPTT vs. 7% of controls (P < 0.0001). However, threshold infusion rate did not differ between weight categories (13.0 vs. 13.1 U/kg/h; P = NS) and approximated the initial infusion rate recommended by nomograms without applying the dose cap (12 U/kg/h). CONCLUSIONS: Adequate anticoagulation time doubled in patients weighing ≥110 kg, suggesting that these patients were not receiving appropriate heparin doses initially to achieve threshold aPTT rapidly. Using initial infusion rate recommended by a nomogram without capping for total body weight is suggested as acceptable in this study. This approach should be further evaluated in a prospective study.

Degradation of thyroid hormone receptor beta 1: existence of stable and unstable forms.

BACKGROUND: The degradation of many nuclear receptors is controlled by ligand-binding and mediated by the ubiquitin-proteasome pathway. However, the mechanisms implicated in thyroid hormone receptor (TR) degradation remain unclear. Our objective was to define the kinetics, mechanisms, and sub-cellular fractions involved in TRs degradation. METHODS: We used pulse-chase analyses, time-course experiments carried out in presence of cycloheximide (to inhibit new protein synthesis), and biochemical fractionation with Western blot analyses to determine the kinetics of the degradation of the TRß isoform, TRß1, in transiently transfected QBI-HEK 293A cells. RESULTS: We observed that TRß1 degradation is mediated by the proteasome pathway. Also, the kinetics of TRß1 degradation is atypical due to the co-existence of more than one TRß1 population, located in different cellular compartments and having different stability profiles. Moreover, TRß1 degradation was unaffected by a mutation in its putative PEST motif, which confers turnover of other proteins. CONCLUSION: Our findings introduce novel evidence suggesting that stable and unstable forms of TRß1, which might have distinct functions, co-exist in cells.

Evaluation of bleeding risk in patients exposed to therapeutic unfractionated or low-molecular-weight heparin: a cohort study in the context of a quality improvement initiative.

BACKGROUND: Bleeding associated with the use of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) can be a serious complication of health-care management and should be the focus of quality improvement initiatives by institutions. OBJECTIVE: To measure the incidence of bleeding with UFH and LMWH and evaluate associated risk factors. METHODS: An observational cohort study was conducted at a secondary and tertiary care hospital in Canada. All adults receiving therapeutic doses of UFH or LMWH between April 2006 and March 2007, with the exception of cardiac surgery patients, were included. Bleeding episodes were classified per the GUSTO scale. RESULTS: Of 3066 hospitalizations, the incidence of moderate or severe bleeding was 3.5%. Advanced age (OR 1.02, 95% CI 1.01 to 1.04; p < 0.001), female sex (OR 1.80, 95% CI 1.21 to 2.66; p = 0.003), UFH instead of LMWH (OR 4.72, 95% CI 2.17 to 10.30; p < 0.001), creatinine clearance (CrCl) (OR 0.89, 95% CI 0.84 to 0.95; p < 0.001, for a difference of 10 mL/min in CrCl), and supratherapeutic activated partial thromboplastin time (aPTT) (OR 3.88, 95% CI 2.25 to 6.69; p < 0.001 for >180 vs <90 seconds) were associated with a higher risk of bleeding in univariate analysis. In a multivariate model without aPTT, CrCl (OR 0.90, 95% CI 0.85 to 0.96; p < 0.001, for a difference of 10 mL/min in CrCl) and UFH (OR 2.35, 95% CI 1.11 to 4.98; p = 0.005) were significant predictors of bleeding. Among the bleeding episodes, 31% were in a postoperative context and 15% were following a puncture. CONCLUSIONS: Our findings show that CrCl and aPTT values, as well as the type of heparin used, are significant predictors of bleeding in patients receiving UFH or LMWH and that dosages should be adjusted to patient weight. The reason for all supratherapeutic aPTT levels should be sought and corrective measures taken immediately.

Low-density lipoprotein receptor-related protein 8 (LRP8) is upregulated in granulosa cells of bovine dominant follicle: molecular characterization and spatio-temporal expression studies.

The low-density lipoprotein (LDL) receptor-related protein 8 (LRP8) is a member of the LDL receptor family that participates in endocytosis and signal transduction. We cloned the full-length bovine LRP8 cDNA in granulosa cells (GC) of the dominant follicle (DF) as well as several LRP8 mRNA splicing variants, including a variant that contains a proline-rich cytoplasmic insert (A759-K817) that is involved in intracellular signaling. Expression of the A759-K817 variant was analyzed in the GC of follicles at different developmental stages: the small follicle (SF; 2-4 mm), the DF at Day 5 (D5) of the estrus cycle, ovulatory follicles (OF) 24 h after hCG injection, and corpora lutea (CL) at D5. RT-PCR analysis showed that expression was predominant in the GC of DF compared to other follicles and CL (P<0.0001), whereas the expression of other related receptors, such as LDLR and VLDLR, did not show differences. Temporal analyses of follicular walls from the OF following hCG treatment revealed a decrease in LRP8 mRNA expression starting 12 h post-hCG treatment (P<0.0001). LRP8 protein was exclusively localized to the GC, with higher levels in the DF than in the SF (P<0.05). RELN mRNA, which encodes an LRP8 ligand, was highly expressed in the theca of the DF as compared to the OF (P<0.004), whereas MAPK8IP1 mRNA, which encodes an LRP8 intracellular interacting partner, is expressed in the GC of the DF. These results demonstrate the differential expression patterns of LRP8, RELN, and MAPK8IP1 mRNAs during final follicular growth and ovulation, and suggest that a RELN/LRP8/MAPK8IP1 paracrine interaction regulates follicular growth.

Identification of downregulated messenger RNAs in bovine granulosa cells of dominant follicles following stimulation with human chorionic gonadotropin.

Molecular determinants and mechanisms involved in ovarian follicular growth, ovulation, and luteinization are not well understood. The objective of this study was to identify genes expressed in bovine granulosa cells (GC) of dominant follicles (DF) and downregulated after hCG-induced ovulation, using the suppression subtractive hybridization (SSH). GC were collected from DF at Day 5 of the estrous cycle and from ovulatory follicles (OF) obtained 23 h following injection of hCG. A subtracted cDNA library (DF-OF) was generated and screened using unsubtracted (DF, OF) and subtracted (DF-OF, OF-DF) cDNAs as complex (32)P-probes. A total of 32 nonredundant cDNAs were identified: 23 cDNAs matched with sequences of known biological function and 9 cDNAs with complete or partial sequences of undefined biological function. Detection of genes known to be downregulated during the periovulatory period in the bovine species, such as CPD, CYP11A1, CYP19A1, FSHR, LRP8/ ApoER2, and SERPINE2, validated the physiological model and analytical techniques used. For a subset of genes, such as ARFGAP3, CYP11A1, CYP19A1, FSHR, FST, GJA1, IDH3, INHBA, LHCGR, LHCGR lacking exon 10, PRC1, PRG1, RPA2, SCD, and TRIB2, gene expression profiles were compared by virtual Northern blot or reverse transcriptase-polymerase chain reaction from follicles obtained at different developmental stages. Results confirmed a downregulation of the respective mRNAs in GC of OF compared with that of DF. We conclude that we have identified novel genes that are downregulated by hCG in bovine GC of DF during the periovulatory period, which may contribute to follicular growth, ovulation, and/or luteinization.

Gene expression profiling of differentially expressed genes in granulosa cells of bovine dominant follicles using suppression subtractive hybridization.

Development of antral follicles beyond 3 to 4 mm in cattle appears as a wave pattern that occurs two to three times during the estrous cycle. Each wave presents a cyclic recruitment of multiple follicles at the 3- to 4-mm stage, followed by the selection of a single follicle that becomes the dominant follicle (DF). The molecular determinants involved in the follicular dominance process remain poorly understood. The objective of the current study was to compare gene expression in granulosa cells (GCs) between growing dominant follicles from Day 5 of the estrous cycle and nonselected small follicles (