Claude Laflamme

Evidence-Based Guidelines for Prevention of Perioperative Hypothermia

Objective: To appraise the available evidence for patient monitoring, perioperative active warming methods, outcomes supporting the prevention of perioperative hypothermia, and implementation strategies for the prevention of perioperative hypothermia. Outcomes: Outcomes assessed included the precision and accuracy of thermometers, efficacy of warming devices including IV fluid warmers and forced-air devices, and surgical site infections and morbid cardiac events associated with PH. Evidence: MEDLINE, EMBASE, and the Cochrane Database were searched to identify randomized controlled trials of efficacy and prospective studies of diagnostic accuracy. Two authors reviewed the abstracts to identify articles for critical appraisal. The methods of the Canadian Task Force on Preventive Health Care were employed to grade study quality and level of evidence, as well as formulate the final recommendations. Recommendations: The evidence supports the use of esophageal temperature probes for temperature monitoring in all patients undergoing abdominal surgery while under general anaesthetic; awake patients and patients in recovery should have temperatures monitored using oral probes (Two studies, Level II-2 evidence, Grade B Recommendation). Active warming with IV fluid warmers and forced-air devices must be employed for all patients whose procedure is expected to last longer than 30 minutes (Eight studies, Level I Evidence, Grade B Recommendation) with a target temperature of >36°C. The prevention of PH with systemic warming measures is necessary to prevent surgical site infections in patients undergoing clean surgery (14% versus 6%, RR 2.39, 95%CI [1.08, 5.28], in a study of preoperative warming), and clean-contaminated surgery (19% versus 6%, RR 3.25, 95%CI [1.35, 7.85], in a study of intraoperative warming) (Two studies, Level I evidence, Grade A Recommendations) and

Consistency Results About Filters and the Number of Inequivalent Growth Types

We use models of set theory described in [2] and [3] to prove the consistency of several combinatorial principles, for example: If ℱ is any filter on N containing all the cofinite sets, then there is a finite-to-one function f : N → N such that f ( ℱ ) is either the filter of cofinite sets or an ultrafilter. As a consequence of our combinatorial principles, we also obtain the consistency of: The partial ordering P of slenderness classes of abelian groups, denned and studied in [4], is a four-element chain. In the remainder of this Introduction, we shall define our terminology and state the combinatorial principles to be considered. In §2, we shall establish some implications between these principles. In §3, we shall prove our consistency results by showing that the strongest of our principles holds in models of set theory constructed in [2] and [3]. A filter on N will always mean a proper filter containing all cofinite sets; in particular, an ultrafilter will necessarily be nonprincipal. We write N ↗ N for the set of nondecreasing functions from the set N of positive integers into itself. A subset ℐ of N ↗ N is called an ideal if it is closed downward (if f ( n ) ≤ g ( n ) for all n and if g ∈ ℐ , then f ∈ ℐ) and closed under binary maximum (if f ( n ) = max( g ( n ), h ( n )) for all n and if g, h ∈ ℐ then f ∈ ℐ ).

Effect of BMP-2 and BMP-7 homodimers and a mixture of BMP-2/BMP-7 homodimers on osteoblast adhesion and growth following culture on a collagen scaffold

In the present study, we studied the involvement of BMP-2 and BMP-7 as homodimers and as a mixture of homodimers in bone regeneration using an engineered bone model. The engineered bone model consisted of a collagen scaffold populated with osteoblasts that acted as a carrier for the BMPs. BMP-2, BMP-7 and a mixture of BMP-2/BMP-7 were used at final concentrations of 10 and 100 ng ml(-1). Osteoblasts seeded onto a collagen scaffold were cultured for 24 h before being stimulated with the BMPs. Four days later, osteoblast adhesion to and growth on the scaffold were assessed. Osteocalcin, IL-6, metalloproteinase (MMP-2 and MMP-9) and protease inhibitor (TIMP-1 and TIMP-2) mRNA and protein levels were measured. Our results showed that the BMP-2, BMP-7 and a mixture of BMP-2/BMP-7 all promoted osteoblast growth on the collagen scaffold, with the mixture of BMP-2/BMP-7 enhancing the most growth. BMP-2 and the mixture of BMP-2/BMP-7 enhanced osteocalcin (an osteoblast differentiation marker) mRNA expression and protein secretion, likely via the IL-6 pathway given that IL-6 secretion was upregulated by BMP-7 and a mixture of BMP-2/BMP-7. BMPs promote extracellular matrix production by inhibiting MMP-2 mRNA and increasing TIMP-1 and TIMP-2 mRNA expressions and protein secretions. BMP-2, BMP-7 and the mixture of BMP-2/BMP-7 could promote bone regeneration via different mechanisms involving IL-6 and MMP inhibitors.

Epidermal growth factor and bone morphogenetic proteins upregulate osteoblast proliferation and osteoblastic markers and inhibit bone nodule formation.

OBJECTIVE The aim of this study was to investigate the in vitro osteogenic activity of EGF in association with bone morphogenetic proteins BMP2 and BMP7. METHODS SaOS-2 (osteoblast-like cell line from human osteosarcoma) were cultured in the presence of EGF and BMPs for various culture periods to assess (a) cell proliferation by MTT assay, (b) Runx2, alkaline phosphatase (ALP) and osteocalcin (OC) mRNA expression using quantitative RT-PCR and ELISA, and (c) bone tissue mineralization using Alizarin Red staining. RESULTS EGF alone was able to stimulate osteoblast growth in a time-dependent manner. When mixed with BMP2, BMP7, and their combination, EGF greatly promoted osteoblast growth, compared to the BMP- and EGF-stimulated cells, suggesting a possible synergistic effect between EGF and BMPs on osteoblast growth. Stimulation with EGF, EGF/BMP2, and EGF/BMP2/BMP7 for 7 days upregulated Runx2 mRNA expression by the osteoblasts. EGF downregulated ALP mRNA expression, which was recovered when the BMP2/BMP7 combination was added to the osteoblast culture. Tested on OC mRNA expression, EGF had no effect and inhibited the enhancing effect of BMP2 and BMP7 on osteocalcin expression. The bone mineralization assay showed that EGF reduced both the number and size of the bone nodules. This reducing effect was observable even in the presence of BMP2 and BMP7. CONCLUSION This study demonstrated that EGF may act in the early phase to promote osteoblast growth and specific marker expression rather than the late phase involving cell differentiation/mineralization.

Forcing with filters and complete combinatorics

Abstract We study ultrafilters produced by forcing, obtaining different combinatorics and related Rudin-Keisler ordering; in particular we answer a question of Baumgartner and Taylor regarding tensor products of ultrafilters. Adapting a method of Blass and Mathias, we show that in most cases the combinatorics satisfied by the ultrafilters recapture the forcing notion in the Levy model.

An algebra and a logic for NC

Abstract Presented here are an algebra and a logic characterizing the complexity class NC1, which consists of functions computed by uniform families of polynomial size, log depth circuits. In both characterizations, NC1 functions are regarded as functions from one class of finite relational structures to another. In the algebraic characterization a recursion scheme called upward tree recursion is applied to a class of simple functions. In the logical characterization, first-order logic is augmented by an operator for defining relations by primitive recursion where it is assumed that every structure has an underlying relation BIT giving the binary representations of integers.

Models with second order properties V: A general principle

Abstract Shelah, S., C. Laflamme and B. Hart, Models with second order properties V: A general principle, Annals of Pure and Applied Logic 64 (1993) 169–194. We present a general framework for carrying out the construction in [2-10] and others of the same type. The unifying factor is a combinatorial principle which we present in terms of a game in which the first player challenges the second player to carry out constructions which would be much easier in a generic extension of the universe, and the second player cheats with the aid of ♦. Section 1 contains an axiomatic framework suitable for the description of a number of related constructions, and the statement of the main theorem 1.9 in terms of this framework. In Section 2 we illustrate the use of our combinatorial principle. The proof of the main result is then carried out in Sections 3–5.

Zapping small filters

We show two methods for diagonalizing filters of the form F σ , first without adding an unbounded real, the other while preserving P-points; the interest lies in an attempt at destroying maximal almost disjoint families with least damage

Canonical Partitions Of Universal Structures

Let