Predictors of mortality in connective tissue disease-associated pulmonary arterial hypertension: a cohort study

Introduction

Pulmonary arterial hypertension (PAH) is a major cause of mortality in connective tissue disease (CTD). We sought to quantify survival and determine factors predictive of mortality in a cohort of patients with CTD-associated PAH (CTD-PAH) in the current era of advanced PAH therapy.

Methods

Patients with right heart catheter proven CTD-PAH were recruited from six specialised PAH treatment centres across Australia and followed prospectively. Using survival methods including Cox proportional hazards regression, we modelled for all-cause mortality. Independent variables included demographic, clinical and hemodynamic data.

Results

Among 117 patients (104 (94.9%) with systemic sclerosis), during 2.6 ± 1.8 (mean ± SD) years of follow-up from PAH diagnosis, there were 32 (27.4%) deaths. One-, two- and three-year survivals were 94%, 89% and 73%, respectively. In multiple regression analysis, higher mean right atrial pressure (mRAP) at diagnosis (hazard ratio (HR) = 1.13, 95% CI: 1.04 to 1.24, P = 0.007), lower baseline six-minute walk distance (HR = 0.64, 95% CI: 0.43 to 0.97, P = 0.04), higher baseline World Health Organization functional class (HR = 3.42, 95% CI: 1.25 to 9.36, P = 0.04) and presence of a pericardial effusion (HR = 3.39, 95% CI: 1.07 to 10.68, P = 0.04) were predictive of mortality. Warfarin (HR = 0.20, 95% CI: 0.05 to 0.78, P = 0.02) and combination PAH therapy (HR = 0.20, 95% CI: 0.05 to 0.83, P = 0.03) were protective.

Conclusions

In this cohort of CTD-PAH patients, three-year survival was 73%. Independent therapeutic predictors of survival included warfarin and combination PAH therapy. Our findings suggest that anticoagulation and combination PAH therapy may improve survival in CTD-PAH. This observation merits further evaluation in randomised controlled trials.     

Aldose reductase modulates cardiac glycogen synthase kinase-3β phosphorylation during ischemia-reperfusion

Earlier studies have demonstrated that aldose reductase (AR) plays a key role in mediating ischemia-reperfusion (I/R) injury. Our objective was to investigate if AR mediates I/R injury by influencing phosphorylation of glycogen synthase kinase-3β (p-GSK3β). To investigate this issue, we used three separate models to study the effects of stress injury on the heart. Hearts isolated from wild-type (WT), human expressing AR transgenic (ARTg), and AR knockout (ARKO) mice were perfused with/without GSK3β inhibitors (SB-216763 and LiCl) and subjected to I/R. Ad-human AR (Ad-hAR)-expressing HL-1 cardiac cells were exposed to hypoxia (0.5% O(2)) and reoxygenation (20.9% O(2)) conditions. I/R in a murine model of transient occlusion and reperfusion of the left anterior descending coronary artery (LAD) was used to study if p-GSK3β was affected through increased AR flux. Lactate dehydrogenase (LDH) release and left ventricular developed pressure (LVDP) were measured. LVDP was decreased in hearts from ARTg mice compared with WT and ARKO after I/R, whereas LDH release and apoptotic markers were increased (P < 0.05). p-GSK3β was decreased in ARTg hearts compared with WT and ARKO (P < 0.05). In ARKO, p-GSK3β and apoptotic markers were decreased compared with WT (P < 0.05). WT and ARTg hearts perfused with GSK3β inhibitors improved p-GSK3β expression and LVDP and exhibited decreased LDH release, apoptosis, and mitochondrial pore opening (P < 0.05). Ad-hAR-expressing HL-1 cardiac cells, exposed to hypoxia (0.5% O(2)) and reoxygenation (20.9% O(2)), had greater LDH release compared with control HL-1 cells (P < 0.05). p-GSK3β was decreased and correlated with increased apoptotic markers in Ad-hAR HL-1 cells (P < 0.05). Treatment with phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) inhibitor increased injury demonstrated by increased LDH release in ARTg, WT, and ARKO hearts and in Ad-hAR-expressing HL-1 cells. Cells treated with protein kinase C (PKC) α/β inhibitor displayed significant increases in p-Akt and p-GSK3β expression, and resulted in decreased LDH release. In summary, AR mediates changes in p-GSK3β, in part, via PKCα/β and Akt during I/R.     

First detection of a human astrovirus type 8 in a child with diarrhea in Belém, Brazil: comparison with other strains worldwide and identification of possible three lineages

This study describes the genetic relationships of the first human astrovirus type-8 (HAstV-8) detected in Belém-Brazil, during a public hospital-based study. This strain was compared with other HAstV-8 strains identified elsewhere which have sequences available at GeneBank. The regions ORF1a (primers Mon348/Mon340) and ORF2 (primers Mon269/Mon270) were analyzed by nucleotide sequencing and a high similarity rate was observed among the Belém strain and other HAstV-8 strains. In ORF1a, homology values of 93-100% were detected, and in ORF2 96-99%. Considering the sequence variation (7%) observed in ORF2 region, it was suggested that HAstV-8 strains could be divided in three different lineages.     

The Biosynthetic Pathway of Astaxanthin in a Green Alga Haematococcus pluvialis as Indicated by Inhibition with Diphenylamine

The effect of diphenylamine on astaxanthin biosynthesis in Haematococcuspluvialis was studied. Cultures induced to produce astaxanthinaccumulated rß-carotene in the presence of the inhibitor.It was found that 30 µM diphenylamine specifically inhibitsthe biosynthesis of astaxanthin at the step of conversion ofrß-carotene to echinenone and canthaxanthin. The resultsimply that these two compounds are genuine intermediates inthe pathway of astaxanthin biosynthesis in H. pluvialis. (Received June 26, 1995; Accepted September 7, 1995)     

Expression of human aldose and aldehyde reductases. Site-directed mutagenesis of a critical lysine 262.

Human aldose reductase (EC 1.1.1.21) and aldehyde reductase (EC 1.1.1.2) are implicated in the development of diabetic complications by a variety of mechanisms, and a number of drugs to inhibit these enzymes have been proposed for the therapy and prevention of these complications. To probe the structure and function of these two enzymes, we used site-directed mutagenesis in the cDNAs of both enzymes to replace lysine 262 with methionine. Wild-type and mutant enzymes were overexpressed in Escherichia coli and purified by anion exchange and affinity chromatography. N-terminal sequence analysis, Western blots, and kinetic studies confirmed the identity of the recombinant wild-type enzymes with the native human placental and liver enzymes. Recombinant aldose reductase (hAR) and aldehyde reductase (hGR) have apparent kinetic constants virtually identical to their respective native enzymes. The mutant aldose reductase (hARK262 greater than M) shows a 66-fold increase in Km for NADPH with respect to the wild type (1.9 +/- 0.4 microM versus 125 +/- 14 microM), whereas the Km for DL-glyceraldehyde increased 35-fold (20 +/- 2 versus 693 +/- 41 microM). The same constants for the mutant aldehyde reductase (hGRK262 greater than M) increased 97- and 86-fold, respectively (from 2.0 +/- 0.4 to 194 +/- 16 microM and from 1.6 +/- 0.4 to 137 +/- 3 mM). These results indicate that lysine 262 in aldose reductase and aldehyde reductase is crucial to their catalytic activity by affecting co-factor binding.     

What did audit achieve? Lessons from preliminary evaluation of a year's medical audit.

OBJECTIVE--To evaluate the experience of a year''s audit of care of medical inpatients. DESIGN--Audit of physicians by monthly review of two randomly selected sets of patients'' notes by 12 reviewers using a detailed questionnaire dedicated to standards of medical records and to clinical management. Data were entered into a database and summary statistics presented quarterly at audit meetings. Assessment by improvement in questionnaire scores and by interviewing physicians. SETTING--1 District general hospital. PARTICIPANTS--About 40 consultant physicians, senior registrars, and junior staff dealing with 140 inpatient records. MAIN OUTCOME MEASURES--Median scores (range 1 to 9) for each item in the questionnaire; two sets of notes were discussed monthly at "general" audit meetings and clinical management of selected common conditions at separate monthly meetings. RESULTS--A significant overall increase in median scores for questions on record keeping occurred after the start of the audit (p less than 0.01), but interobserver variation was high. The parallel audit meetings on clinical management proved to be more successful than the general audits in auditing medical care and were also considered to be more useful by junior staff. CONCLUSIONS AND ACTION--Medical audit apparently resulted in appreciable improvements in aspects of care such as clerking and record keeping. Analysis of the scores of the general audits has led to the introduction of agreed standards that can be objectively measured and are being used in a further audit, and from the results of the audits of clinical management have been developed explicit guidelines, which are being further developed for criterion based audit.     

Atypical rotavirus among diarrhoeic children living in Belém, Brazil

Atypical rotaviruses were detected in faeces from two diarrhoeic children living in Belém, Pará, Brazil. Rotavirus particles were detected by electron microscopy and the RNA electrophoresis showed patterns which were compatible with group C rotaviruses. Tests for the presence of group A antigen by enzyme-linked-immunosorbent assay (ELISA) were negative. The two children had three successive rotavirus infections and in both cases the atypical strains were excreted at the time of the third infection, causing a mild and short-lasting disease.     

Primary amines do not prevent the endocytosis of epidermal growth factor into 3T3 fibroblasts

Various amines block the degradation of endocytosed epidermal growth factor (EGF) without affecting the binding of the hormone to its surface receptors. However, studies based on fluorescence microscopy demonstrate that amines block the internalization of alpha 2-macroglobulin and EGF by preventing it from clustering in clathrin coated pits. In order to resolve this controversy we have studied in detail the effect of various amines on the localization and processing of fluorescent and radiolabelled EGF. We have explored the effect of amines on EGF binding and localization, receptor mobility, membrane fluidity, receptor down regulation, hormone degradation and release of degradative products as a function of time and temperature. Our conclusions are as follows. 1. Primary amines prevent the formation of visible patches of fluorescent EGF and alpha 2-macroglobulin on the cell surface at least for 15 min, thus increasing the diffusion coefficients and the mobile fraction of EGF-receptor complexes on the cell surface. 2. Amines do not block the endocytosis of EGF and alpha 2-macroglobulin. On most cells fluorescent EGF and alpha 2-macroglobulin are clustered and endocytosed within 30-45 min at 37 degrees C. 3. Amines do not effect the internalization of 125I-labelled-EGF and the down regulation of EGF receptors. 4. Amines block the degradation of the endocytosed EGF.