Surface immobilization of bone morphogenetic protein 2 via a self-assembled monolayer formation induces cell differentiation

Bone extracellular matrix consists of a network of proteins in which growth factors, like bone morphogenetic protein 2 (BMP-2), are embedded and released upon matrix turnover and degradation. Recombinant human (rh)BMP-2 shows promise in enhancing bone fracture repair, although issues regarding finding a suitable delivery system still limit its extensive clinical use. The aim of this study is to determine which cell activities are triggered by the presentation of immobilized rhBMP-2. For this purpose gold surfaces were first decorated with a self-assembled monolayer consisting of a hetero-bifunctional linker. rhBMP-2 was covalently bound to the surfaces via this linker and used to investigate the cellular responses of C2C12 myoblasts. We show that covalently immobilized rhBMP-2 (iBMP-2) initiates short-term signaling events. Using a BMP-responsive reporter gene assay and western blotting to monitor phosphorylation of Smad1/5/8 we prove that iBMP-2 activates BMP-dependent signal transduction. Furthermore, we demonstrate that iBMP-2 suppresses myotube formation and promotes the osteoblast phenotype in C2C12 cells. The bioactivity of surface-bound rhBMP-2 presented in this study is not due to its release into the medium. As such, our simple approach paves the way for the controlled local presentation of immobilized growth factors, limiting degradation while still maintaining biological activity.     

The APACHE III prognostic system. Risk prediction of hospital mortality for critically ill hospitalized adults

The objective of this study was to refine the APACHE (Acute Physiology, Age, Chronic Health Evaluation) methodology in order to more accurately predict hospital mortality risk for critically ill hospitalized adults. We prospectively collected data on 17,440 unselected adult medical/surgical intensive care unit (ICU) admissions at 40 US hospitals (14 volunteer tertiary-care institutions and 26 hospitals randomly chosen to represent intensive care services nationwide). We analyzed the relationship between the patient's likelihood of surviving to hospital discharge and the following predictive variables: major medical and surgical disease categories, acute physiologic abnormalities, age, preexisting functional limitations, major comorbidities, and treatment location immediately prior to ICU admission. The APACHE III prognostic system consists of two options: (1) an APACHE III score, which can provide initial risk stratification for severely ill hospitalized patients within independently defined patient groups; and (2) an APACHE III predictive equation, which uses APACHE III score and reference data on major disease categories and treatment location immediately prior to ICU admission to provide risk estimates for hospital mortality for individual ICU patients. A five-point increase in APACHE III score (range, 0 to 299) is independently associated with a statistically significant increase in the relative risk of hospital death (odds ratio, 1.10 to 1.78) within each of 78 major medical and surgical disease categories. The overall predictive accuracy of the first-day APACHE III equation was such that, within 24 h of ICU admission, 95 percent of ICU admissions could be given a risk estimate for hospital death that was within 3 percent of that actually observed (r2 = 0.41; receiver operating characteristic = 0.90). Recording changes in the APACHE III score on each subsequent day of ICU therapy provided daily updates in these risk estimates. When applied across the individual ICUs, the first-day APACHE III equation accounted for the majority of variation in observed death rates (r2 = 0.90, p less than 0.0001).     

Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. The ACCP/SCCM Consensus Conference Committee. American College of Chest Physicians/Society of Critical Care Medicine.

An American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference was held in Northbrook in August 1991 with the goal of agreeing on a set of definitions that could be applied to patients with sepsis and its sequelae. New definitions were offered for some terms, while others were discarded. Broad definitions of sepsis and the systemic inflammatory response syndrome were proposed, along with detailed physiologic parameters by which a patient may be categorized. Definitions for severe sepsis, septic shock, hypotension, and multiple organ dysfunction syndrome were also offered. The use of severity scoring methods when dealing with septic patients was recommended as an adjunctive tool to assess mortality. Appropriate methods and applications for the use and testing of new therapies were recommended. The use of these terms and techniques should assist clinicians and researchers who deal with sepsis and its sequelae.     

Human pharmacology studies with a new, orally active stimulant of cardiac adrenergic beta-receptors.

The effects of single oral doses of 5, 10, and 20 mg. of a new cardioselective β-stimulant, preparation C $\text{50,005}\text{A-Ba}$, were tested and compared with the response to placebo in eight healthy volunteers (four aged 23 to 26 years and four aged 49 to 55 years). The compound induced a doserelated increase in myocardial contractility (reduction of 17 to 24 msec. in PEP_c) and in heart rate, which was accelerated by 8 to 20 beats/minute by comparison with the placebo values. The rise in systolic pressure observed in response to C $\text{50,005}\text{A-Ba}$ was both dose-related and dependent on the age of the subjects; in the younger group there was an increase of 16 to 31 mm. Hg and in the older group an increase of 7 to 21 mm. Hg. A slight decrease in diastolic pressure was noted, which was likewise more prominent in the younger subjects. These changes were ascribed to a decrease due to aging in the responsiveness of the adrenergic β-receptors to stimulation. The effects of the compound set in quickly, reached their maximum within 30 to 60 minutes, and persisted for about 4 hours. The only side effects observed were slight palpitations. Depression of the ST segment was noted in one 55-year-old subject and was interpreted as a manifestation of latent coronary disease. In view of this finding, it seems possible that the preparation could be used as a diagnostic agent for a simple test of coronary function. Continuous E.C.G. recordings over a period of $\text{5}\text{3}\text{4}\text{hours}$, including three ergometer tests at submaximum effort, showed that by comparison with placebo, C $\text{50,005}\text{A-Ba}$ caused a slight increase in the frequency of isolated ventricular and supraventricular premature contractions, and also in the incidence and intensity of sinus arrhythmias not due to respiration. Essentially the same changes in cardiac rhythm were observed in four young volunteers during continuous E.C.G. recordings over a period of 9 hours in response to the repeated administration of C $\text{50,005}\text{A-Ba}$ in a dosage of 15 mg. three times a day on two consecutive days. The differences from the corresponding placebo values were, however, not statistically significant.C $\text{50,005}\text{A-Ba}$ is thus an orally active cardiostimulant agent with a high degree of β₁-receptor selectivity and with only a very slight arrhythmogenic potential. It is well tolerated and could afford beneficial effects in the treatment of heart failure or as a countermeasure in therapy with β-blockers.