Submaximal heart and pulmonary evaluation: a novel noninvasive test to identify pulmonary hypertension in patients with systemic sclerosis

OBJECTIVE

Pulmonary hypertension (PH) is a leading cause of death in patients with systemic sclerosis (SSc; scleroderma). Although right-sided heart catheterization (RHC) is the gold standard for diagnosing PH, it is an invasive test with associated risks. The submaximal heart and pulmonary evaluation (step test) is a noninvasive, submaximal stress test that could be used to identify patients with PH. The purpose of this study is to assess the correlation between change in end tidal carbon dioxide (ΔPETCO2 ) from rest to end-exercise on the step test and mean pulmonary artery pressure (mPAP) on RHC in SSc patients.

METHODS

This is a retrospective cohort study of patients with limited or diffuse cutaneous SSc who were evaluated in an academic cardiology practice between November 2007 and November 2011 and underwent a step test and RHC. Statistical analysis was performed using Spearman's correlation test and multivariable linear regression.

RESULTS

A total of 679 charts were reviewed. Nineteen SSc patients who underwent a step test and RHC were included. ΔPETCO2 was negatively correlated with mPAP (r = -0.82, P < 0.0001). In a multivariable linear regression model evaluating the relationship between ΔPETCO2 and mPAP, controlling for age, sex, and time between and order of step test and RHC, ΔPETCO2 remained the only variable statistically significantly associated with mPAP (P < 0.001). The step test had a sensitivity of 100%, specificity of 75%, positive predictive value of 93.8%, and negative predictive value of 100% for the diagnosis of PH.

CONCLUSION

ΔPETCO2 on the step test has a strong, statistically significant negative correlation with mPAP on RHC.

Treatment of early diffuse systemic sclerosis skin disease

Diffuse systemic sclerosis carries a high morbidity and mortality. The Prospective Registry of Early Systemic Sclerosis (PRESS), a multicentre incident cohort study of patients with early diffuse cutaneous systemic sclerosis, has the goal of advancing the understanding of disease pathogenesis and identifying novel biomarkers. In this review, PRESS investigators discuss the evidence pertaining to the more commonly used treatments for early diffuse SSc skin disease including methotrexate, mycophenolate, cyclophosphamide, azathioprine, and intravenous immunoglobulin. This review highlights the unmet need for effective treatment in early diffuse SSc as well as its more rigorous study. Nonetheless, the PRESS investigators aim to decrease intra- and inter-institutional variability in prescribing in order to improve the understanding of the clinical course of early diffuse SSc skin disease.

Low prevalence of coeliac disease in patients with systemic sclerosis: a cross-sectional study of a registry cohort

OBJECTIVES

Two prior studies suggested that coeliac disease (CD) has a higher prevalence rate (8%) in SSc than in the general population (1%), but these studies were limited by small numbers and the use of traditional coeliac screening antibody tests, where newer ones with improved accuracy have since emerged. Our aim was to determine the prevalence of CD in a larger SSc population using a more modern serological approach to coeliac testing and to correlate coeliac antibody status with gastrointestinal symptoms.

METHODS

Stored sera from 72 SSc patients in the Scleroderma Registry at the Hospital for Special Surgery were tested for anti-tissue transglutaminase (traditional) and anti-deamidated gliadin peptide (novel) antibodies. If any of these antibodies were positive, anti-endomysial antibodies were tested and confirmatory small-bowel endoscopy and biopsy were obtained. Registry clinical data were used to determine whether antibody status correlated with gastrointestinal symptoms.

RESULTS

The prevalence of coeliac antibodies in our SSc population was 3/72 (4%). No significant differences with respect to gastrointestinal symptoms were seen in the coeliac antibody-positive compared with -negative SSc patients. No cases of confirmed CD were seen in our cohort.

CONCLUSION

Contrary to the only two previously published studies, the low prevalence of CD that we found does not suggest that concurrent CD is a common cause of gastrointestinal complaints in SSc patients.

Imatinib mesylate (Gleevec) in the treatment of diffuse cutaneous systemic sclerosis: results of a 1-year, phase IIa, single-arm, open-label clinical trial

Objective

To assess the safety and effectiveness of imatinib mesylate in the treatment of diffuse cutaneous systemic sclerosis (dcSSc).

Methods

In this phase IIa, open-label, single-arm clinical trial, 30 patients with dcSSc were treated with imatinib 400 mg daily. Patients were monitored monthly for safety assessments. Modified Rodnan skin scores (MRSS) were assessed every 3 months. Pulmonary function testing, chest radiography, echocardiography and skin biopsies were performed at baseline and after 12 months of treatment.

Results

Twenty-four patients completed 12 months of therapy. 171 adverse events (AE) with possible relation to imatinib were identified; 97.6% were grade 1 or 2. Twenty-four serious AE were identified, two of which were attributed to study medication. MRSS decreased by 6.6 points or 22.4% at 12 months (p=0.001). This change was evident starting at the 6-month time point (Δ=−4.5; p<0.001) and was seen in patients with both early and late-stage disease. Forced vital capacity (FVC) improved by 6.4% predicted (p=0.008), and the diffusion capacity remained stable. The improvement in FVC was significantly greater in patients without interstitial lung disease. Health-related quality of life measures improved or remained stable. Blinded dermatopathological analysis confirmed a significant decrease in skin thickness and improvement in skin morphology.

Conclusions

Treatment with imatinib was tolerated by most patients in this cohort. Although AE were common, most were mild to moderate. In this open-label experience, improvements in skin thickening and FVC were observed. Further investigation of tyrosine kinase inhibition for dcSSc in a double-blind randomised placebo controlled trial is warranted.

ClinicalTrials.gov, NCT00555581

Mutants that produce nitrogenase in the presence of ammonia

Mutants of Azotobacter vinelandii that fix N(2) in the presence of excess NH(4) (+) have been isolated. A mutant that was unable to synthesize component I and component II of nitrogenase was spontaneously reverted to the N(2)-fixing phenotype. Of 21 revertants picked, 7 revertants were not as sensitive as the wild type to repression. A derepressed mutant is as sensitive as the wild type to growth inhibition by 2-methylalanine in the presence of glucose.

Elevations of creatine kinase in patients treated with imatinib mesylate (Gleevec)

Imatinib mesylate is used with increasing frequency and duration for the treatment of chronic myelogenous leukemia (CML), gastrointestinal stromal tumor (GIST), and other neoplastic conditions. Although muscular complaints are common, elevations of creatine kinase (CK) are listed as <1% in the product label. We describe here a case of rhabdomyolysis likely related to imatinib as well as the results of a prospective evaluation of CK levels in a cohort of patients on imatinib for CML or GIST. We found a high prevalence of CK abnormalities in this group and believe that CKs should be monitored during therapy with imatinib.

Spontaneous aortic dissection and rupture in a patient with neurofibromatosis

Vascular involvement in neurofibromatosis type I is a well-recognized but rare feature of the disease. This case report is the first such describing acute aortic dissection and rupture in a patient who also had incidental aneurysms of his carotid and iliac arteries. A review of the literature about pathogenesis and management strategies is also presented.

The significance of early postoperative duplex studies following carotid endarterectomy

This study was conducted to evaluate the significance of duplex ultrasound performed soon after carotid endarterectomy. The records of patients with 150 carotid endarterectomies and postoperative duplex ultrasound within 24 h were reviewed. Eleven (7.3%) had abnormal studies with > or =50% stenosis. Two patients with abnormal studies sustained a perioperative stroke and three patients underwent reoperation for persistent lesions (P<0.0001). Preoperative and postoperative cerebral imaging studies (computed tomography (CT) or magnetic resonance imaging (MRI)) were performed on 114 patients. Seven of these demonstrated areas of infarction and all seven had abnormal duplex ultrasound studies. Twenty-six CT scans were performed with two positive for cerebral infarction in the two patients with clinical stroke. In the 88 MRI studies, five demonstrated small, subcortical focal areas of ischemia, which were clinically silent. The relationship of infarction on postoperative cerebral studies and abnormal postoperative duplex ultrasound was significant (P<0.0001). It was concluded that early postoperative duplex ultrasound studies of > or =50% stenosis demonstrate significant association with postoperative stroke or reoperation, as well as with ischemic changes on brain imaging studies. Earlier detection with intraoperative duplex would probably be more advantageous than postoperative duplex ultrasound.

Cerebral microembolism and ischemic changes associated with carotid endarterectomy

PURPOSE

The purpose of this study is to characterize microembolic signals (MS) that occur during the various phases of carotid endarterectomy (CEA) and to consider their relationship to postoperative changes on magnetic resonance imaging (MRI).

METHODS

This was a retrospective study of 76 patients who underwent 78 carotid endarterectomies at a referral center. Perioperative transcranial Doppler monitoring and MRI were performed before and after CEA. The types of MS that occurred during phases of surgery were analyzed and compared with MRI changes.

RESULTS

We observed a clinical stroke in one patient (1.3%) and ipsilateral small areas of silent ischemic change on seven postoperative MRI studies (9.0%). In 95% of CEAs, MS were detected. Only those MS observed in the recovery room that occurred at a rate of more than five per 15 minutes were associated with postoperative MRI ischemic changes (p < 0.0001).

CONCLUSIONS

Ischemic changes on MRI after CEA are related to postoperative MS.

Early outcome of in situ femorotibial reconstruction among patients with diabetes alone versus diabetes and end-stage renal failure: analysis of 83 limbs

PURPOSE

Both end-stage renal disease and diabetes have been demonstrated to have a negative effect on the outcome of infrainguinal arterial reconstruction, primarily because of increased perioperative morbidity and wound complications. This study was undertaken to determine whether the combination of these comorbid factors affects the outcome of distal arterial reconstruction.

METHODS

Eighty-three distal lower extremity arterial bypasses originating from the femoral artery and terminating at the peroneal, anterior, or posterior tibial artery were performed on 76 patients over a 5-year period at a tertiary care medical center. Autogenous greater saphenous vein was used as the bypass conduit in all instances. Combined inflow and composite vein procedures were excluded.

RESULTS

There was one perioperative death, for a mortality rate of 1.2%. The diabetes mellitus (DM) plus end-stage renal disease (DM+ESRD) cohort displayed a significantly lower 1-year primary patency rate compared with the diabetes mellitus cohort, 53% versus 82% (p < 0.02). However, the limb salvage rate for the DM+ESRD and DM cohorts during the same time interval were not significantly different, 63% versus 84% (p < 0.06). The 52% 1-year survival rate for the DM+ESRD cohort was strikingly lower than the 90% 1-year survival rate for the DM cohort (p < 0.002).

CONCLUSION

Despite the use of the optimal autogenous conduit, the combination of diabetes and end-stage renal disease can be expected to significantly decrease primary graft patency without affecting limb salvage. The greatest effect of these comorbid factors is on patient survival.

The ability of right- and left-hemisphere-damaged individuals to produce and interpret prosodic cues marking phrasal boundaries

Two experiments were conducted with the purpose of investigating the ability of right- and left-hemisphere-damaged individuals to produce and perceive the acoustic correlates to phrase boundaries. In the production experiment, the utterance pink and black and green was elicited in three different conditions corresponding to different arrangements of colored squares. Acoustic analyses revealed that both left- and right-hemisphere-damaged patients exhibited fewer of the expected acoustic patterns in their productions than did normal control subjects. The reduction in acoustic cues to phrase boundaries in the utterances of both patient groups was perceptually salient to three trained listeners. The perception experiment demonstrated a significant impairment in the ability of both left-hemisphere-damaged and right-hemisphere-damaged individuals to perceive phrasal groupings. Results are discussed in relation to current hypotheses concerning the cerebral lateralization of speech prosody.

Rhyme priming in aphasia: the role of phonology in lexical access

The present experiment was conducted to explore the facilitory effects of rhyme in lexical processing in brain-damaged individuals. Normal subjects and non-fluent and fluent aphasic subjects performed auditory lexical decision and rhyme judgement tasks, in which prime-target pairs were phonologically related (either identical or rhyming) or unrelated. Results revealed rhyme facilitation of lexical decisions to real-word targets for normal and non-fluent aphasic subjects; for fluent aphasic subjects, results were equivocal. In the rhyme judgement task, facilitory effects of rhyme were found for all three groups with real-word targets. None of the groups showed clear rhyme facilitation effects with non-word targets in either task. Findings are discussed with reference to the role of phonology in lexical processing in normal and aphasic populations.

Feedback inhibition of nitrogenase

No inhibition of nitrogenase activity by physiological levels of NH4+ or carbamyl phosphate was observed in extracts of Azotobacter vinelandii. All of the 15N2 reduced by cultures which received no NH4+ was found in the cells. By contrast, more than 95% of the 15N2 reduced by cultures which had been given NH4+ was found in the medium. Failure to examine the culture medium would lead to the erroneous conclusion that N2 fixation is inhibited by NH4+. Nitrogenase in a derepressed mutant strain of A. vinelandii was fully active in vivo in the presence of NH4+. The addition of NH4Cl to N2-fixing cultures resulted in no decrease in the N2-reducing activity of intact cells of Klebsiella pneumoniae or Clostridium pasteurianum and only a small (15%) decrease in A. vinelandii. Therefore, no significant inhibition of nitrogenase by NH4+ or metabolites derived from NH4+ exists in A. vinelandii, K. pneumoniae, or C. pasteurianum.

Ammonium and methylammonium transport by the nitrogen-fixing bacterium Azotobacter vinelandii

Azotobacter vinelandii, grown with NH4+ as nitrogen source, was shown to possess an active transport system which can take up NH4+ against a concentration gradient of 58-fold. The properties of the NH4+ uptake system were investigated with the NH4+ analog CH3NH3+. The use of this analog was justified on the basis of the conclusion that the uptake of NH4+ and CH3NH3 involves a common binding site, as shown by the competitive inhibition of CH3NH3+ uptake by NH4+ (Ki approximately 3 microM). A Lineweaver-Burk plot for CH3NH3+ uptake revealed a biphasic curve, suggesting the existence of two CH3NH3+ (NH4+) uptake systems with apparent Km's for CH3NH3+ equal to 61 microM and 661 microM. The uptake of CH3NH3+ was inhibited by arsenate, as well as by cyanide or carbonyl cyanide-m-chlorophenyl hydrazone, indicating that phosphate bond energy is required.

Biochemistry and genetics of Klebsiella pneumoniae mutant strains unable to fix N2

Selected mutant strains of Klebsiella pneumoniae that are unable to fix nitrogen have been characterized according to nitrogenase component activity as well as antigenic cross-reacting material. The lesions in these strains have been mapped by transduction, and the results indicate that there are at least five genes specifically responsible for nitrogen fixation in vivo. Besides genes that specify the structure of the two nitrogenase components, there is a gene for a factor that is required for component I activity and a gene that codes for a factor possibly involved in electron transport to component II. A mutation in another site does not allow the organism to produce either of the nitrogenase components. All of these genes are co-transducible with the gene that specifics the structure of histidinol dehydrogenase.

Removing substances from blood by affinity chromatography. I. Removing bilirubin and other albumin-bound substances from plasma and blood with albumin-conjugated agarose beads

Substances such as bilirubin that bind tightly to plasma proteins cannot readily be removed from blood. We describe here the use of affinity chromatography as a new approach to the removal of proteinbound metabolites and toxins from blood. Agarose beads were coupled via cyanogen bromide to human serum albumin so as to contain 30-50 mg of albumin/g wet wt. Such beads, when exposed to plasma from a patient with congenital nonhemolytic jaundice labeled with [(14)C]-bilirubin, bound more than 150 mug bilirubin/g of beads. The binding was saturable, concentration-dependent, relatively independent of flow rate, and reversible by elution with plasma, albumin, or 50% (vol/vol) ethanol. The beads could be repeatedly reused without loss of efficiency after ethanol elution and long storage in the cold. Salicylate, cortisol, and taurocholate, which bind weakly to albumin, were retarded by the beads but eluted with neutral buffer. Thyroxine, taurolithocholate, chenodeoxycholate, and digitoxin bound tightly but were eluted with 50% ethanol. Digoxin did not bind at all. When whole blood was passed over agarose-albumin beads, bilirubin was removed, calcium and magnesium fell slightly, but red cells, white cells, platelets, clotting factors, and a variety of electrolytes and proteins were substantially unchanged. Agarose-albumin beads may be useful for removing protein-bound substances from the blood of patients with liver failure, intoxication with protein-bound drugs, or specific metabolic deficits. Furthermore, it may be possible to make useful adsorbents by attaching other proteins to agarose or other polymer beads.

Amyloidosis induced in mice by Escherichia coli endotoxin

Amyloidosis was produced in mice by repeated subcutaneous injections of 0.5-or 0.005-milligram amounts of Escherichia coli endotoxin. Of the two strains of mice examined, amyloidosis was induced more readily in one than in the other. The ability of endotoxin to induce amyloidosis lends support to the view that stimulation of reticuloendothelial cells leads to amyloid formation.