Stimulation of free radical generation in human leukocytes by various agents including tumor necrosis factor is a calmodulin dependent process

The mechanism(s) involved in the generation of free radicals in human leukocytes by phorbol myristate acetate (PMA), formyl-methionyl-leucyl-phenylalanine (FMP), lipopolysaccharide (LPS), arachidonic acid (AA), and recombinant-tumor necrosis factor-1-alpha (r-TNF-1 alpha) was investigated. Calmodulin antagonists, chlorpromazine and trifluoperazine, inhibited free radical generation in human leukocytes by these stimulants. Dexamethosone, an inhibitor of phospholipase A2, could also block free radical generation in human leukocytes induced by r-TNF 1 alpha. PMA, FMP, LPS and TNF can activate phospholipase A2 and induce the release of AA from the cell membrane lipid pool. AA induced free radical generation in human leukocytes can be inhibited by calmodulin antagonists. Hence, it is likely that calmodulin dependent events play a crucial role in the generation of free radicals by human leukocytes in response to various stimulants including TNF.     

Adult specific expression and induction of cytochrome P450tpr in house flies

Cytochrome P450_tpr is a xenobiotic metabolizing P450 that is found in house flies (Musca domestica). To better understand the regulation of cytochrome P450_tpr, the effects of 21 potential monooxygenase inducers were examined for their ability to induce total cytochromes P450 and cytochrome P450_tpr levels in adult flies. Six compounds caused induction of total cytochromes P450 per mg protein in adult susceptible (CS) house flies: ethanol (1.6-fold), phenobarbital in food (1.5-fold) or water (1.5-fold), naphthalene (1.3-fold), DDT (1.3-fold), xanthotoxin (1.4-fold), and α-pinene (1.2-fold). Six compounds were found to be inducers of cytochrome P450_tpr: piperonyl butoxide in food (1.9-fold), phenobarbital in food (1.4-fold) and water (3.4-fold), clofibrate (1.3-fold), xanthotoxin (1.3-fold), methohexital (1.3-fold), and isosafrole (1.3-fold). Comparison of our results with house fly P450 6A1 indicates that there are specific inducers for each of these individual P450s as well as compounds that induce both P450s. Total P450s were inducible by PB in CS house fly larvae, but not in LPR larvae. Immunoblotting revealed no detectable P450_tpr in control or PB-treated larvae in either strain. Thus, although total P450s are inducible in the susceptible strain larvae, P450_tpr does not appear to be normally present or inducible with PB in larvae of either strain. Northern blots of phenobarbital (in water) treated CS flies indicated that there was a 4.2-fold increase in the P450_tpr (i.e., CYP6D1) mRNA levels over the untreated flies. In the multiresistant LPR strain there was no apparent induction of CYP6D1 mRNA by phenobarbital. Following phenobarbital induction, the level of CYP6D1 mRNA in the CS strain was about half of the level in the LPR strain. © 1996 Wiley-Liss, Inc.     

Withanolide A series steroidal lactones from Eucalyptus globulus bark

A new steroidal lactone of the Withanolide A series has been isolated from the supercritical fluid extract of Eucalyptus globulus L. (bark) as a major component (I) along with a known structurally similar steroidal lactone as minor component (II). The structural identification of the new lactone was accomplished by different spectroscopic techniques viz. ¹H and ¹³C NMR, etc. The relative stereochemistry was unequivocally determined from the X-ray crystallography.     

Molecular dynamics simulation of drug uptake by polymer

Drug uptake by polymer was modeled using a molecular dynamics (MD) simulation technique. Three drugs—doxorubicin (water soluble), silymarin (sparingly water soluble) and gliclazide (water insoluble)—and six polymers with varied functional groups—alginic acid, sodium alginate, chitosan, Gantrez AN119 (methyl-vinyl–ether-co-malic acid based), Eudragit L100 and Eudragit RSPO (both acrylic acid based)—were selected for the study. The structures were modeled and minimized using molecular mechanics force field (MM+). MD simulation (Gromacs-forcefield, 300 ps, 300 K) of the drug in the vicinity of the polymer molecule in the presence of water molecules was performed, and the interaction energy (IE) between them was calculated. This energy was evaluated with respect to electric-dipole, van der Waals and hydrogen bond forces. A good linear correlation was observed between IE and our own previous data on drug uptake^* [R ² = 0.65, R_adj² = 0.65,R_pre² = 0.56, {\hbox{R}}_{\rm{adj}}^2 = 0.65,{\hbox{R}}_{\rm{pre}}^2 = 0.56, and a F ratio of 30.25, P < 0.001; Devarajan et al. (2005) J Biomed Nanotechnol 1:1–9]. Maximum drug uptake by the polymeric nanoparticles (NP) was achieved in water as the solvent environment. Hydrophilic interaction between NP and water was inversely correlated with drug uptake. The MD simulation method provides a reasonable approximation of drug uptake that will be useful in developing polymer-based drug delivery systems.     

Impact of specialist follow-up in outpatients with congestive heart failure

Background

There is uncertainty about whether physician specialty influences the outcomes of outpatients with congestive heart failure after adjustment for differences in case mix. Our objective was to determine the impact of physician specialty on outcomes in outpatients with new-onset congestive heart failure.

Methods

The study was a population-based retrospective cohort study involving patients with new-onset congestive heart failure discharged from 128 acute care hospitals in Alberta between Apr. 1, 1998, and July 1, 2000. Outcomes were resource utilization (clinic visits, emergency department visits and hospital admissions) and survival at 30 days and 1 year.

Results

A total of 3136 patients were discharged from hospital with a new diagnosis of congestive heart failure (median age 76 years, 50% men). Of these, 1062 (34%) received no follow-up visits for cardiovascular care, 738 (24%) were seen by a family physician (FP) alone, 29 (1%) by a specialist (cardiologist or general internist) alone and 1307 (42%) by both a specialist and an FP. Compared with patients who received no follow-up cardiovascular care, patients who received regular cardiovascular follow-up visits with a physician had fewer visits to the emergency department (38% v. 80%), fewer were admitted to hospital (13% v. 94%), and the adjusted 1-year mortality was lower (22% v. 37%) (all p < 0.001). Compared with patients who received combined specialist and FP care, patients cared for exclusively by FPs had fewer outpatient visits (median 9 v. 17 in the first year), fewer of these patients presented to the emergency department (24% v. 45% in the first year), and fewer were readmitted for cardiovascular care (7% v. 16%) (all p < 0.001). However, the adjusted mortality at 1 year was lower among patients treated with combined care (17% v. 28%, p < 0.001) despite a higher burden of comorbidities. In a multivariate model adjusting for comorbidities (with no cardiovascular follow-up visits as the reference category), the mortality was lower among patients followed on an outpatient basis by an FP alone (odds ratio [OR] 0.66, 95% confidence interval [CI] 0.53–0.82) or by an FP and a specialist (OR 0.34, 95% CI 0.28–0.42). In a proportional hazards model with time-dependent covariates (with adjustment for frequency of follow-up visits), the risk of all-cause mortality was reduced significantly (hazard ratio 0.98, 95% CI 0.97– 0.99) with each specialist visit compared with FP care alone.

Interpretation

Patients with congestive heart failure followed by both specialists and FPs had significantly better survival than those followed by FPs alone (or those who received no specific cardiovascular follow-up care). Methods to improve timely and appropriate access to specialists and to improve collaborative care structures are needed.Congestive heart failure (CHF) afflicts up to 2% of North American adults and, despite many advances in diagnosis and therapy, still portends a poor prognosis, with 1-year mortality of 30%–50%.^1,2,3,4,5 Although the prognosis of patients with CHF is poor even with optimal management, suboptimal diagnosis, investigation and treatment of heart failure and comorbidities (e.g., coronary artery disease) in community-dwelling patients contributes to poor survival.^6,7,8,9In previous studies hospital inpatients with CHF who were cared for by specialists received more evidence-based therapies and had better outcomes than those cared for by nonspecialists.^{8,10,11,12,13} However, none of these studies examined the care delivered after discharge from hospital. Although management in specialized multidisciplinary clinics is associated with better outcomes,¹⁴ it is unclear whether similar benefits can be expected when patients are cared for by specialist physicians operating outside the setting of a multidisciplinary clinic. Two recent studies from the United States that reported better outcomes with specialist care^7,15 were flawed, in that neither study adjusted for frequency of outpatient visits or the possibility of time-dependent bias¹⁶ (whereby some variables, including the number of visits, will change over time).To address this important public health issue, we sought to determine whether there is a relation between ambulatory care follow-up and outcomes in patients with new-onset CHF.