Skeletal muscle adaptations to interval training in patients with advanced COPD

STUDY OBJECTIVES

To investigate the response to interval exercise (IE) training by looking at changes in morphologic and biochemical characteristics of the vastus lateralis muscle, and to compare these changes to those incurred after constant-load exercise (CLE) training.

DESIGN

Randomized, controlled, parallel, two-group study (IE vs CLE training).

SETTING

Multidisciplinary, outpatient, hospital-based, pulmonary rehabilitation program.

PATIENTS

Nineteen patients with stable advanced COPD (mean +/- SEM FEV1, 40 +/- 4% predicted).

INTERVENTIONS

Patients (n = 10) assigned to IE training exercised at a mean intensity of 124 +/- 15% of baseline peak exercise capacity (peak work rate [Wpeak]) with 30-s work periods interspersed with 30-s rest periods for 45 min/d. Patients (n = 9) allocated to CLE training exercised at a mean intensity of 75 +/- 5% Wpeak for 30 min/d. Patients exercised 3 d/wk for 10 weeks.

MEASUREMENTS AND RESULTS

Needle biopsies of the right vastus lateralis muscle were performed before and after rehabilitation. After IE training, the cross-sectional areas of type I and IIa fibers were significantly increased (type I before, 3,972 +/- 455 microm2; after, 4,934 +/- 467 microm2 [p = 0.004]; type IIa before, 3,695 +/- 372 microm2; after, 4,486 +/- 346 microm2 [p = 0.008]), whereas the capillary-to-fiber ratio was significantly enlarged (from 1.13 +/- 0.08 to 1.24 +/- 0.07 [p = 0.013]). Citrate synthase activity increased (from 14.3 +/- 1.4 to 20.5 +/- 4.2 micromol/min/g), albeit not significantly (p = 0.097). There was also a significant improvement in Wpeak (by 19 +/- 5%; p = 0.04) and in lactate threshold (by 17 +/- 5%; p = 0.02). The magnitude of changes in all the above variables was not significantly different compared to that incurred after CLE training. During training sessions, however, ratings of dyspnea and leg discomfort, expressed as fraction of values achieved at baseline Wpeak, were significantly lower (p < 0.05) for IE training (73 +/- 9% and 60 +/- 8%, respectively) compared to CLE training (83 +/- 10% and 87 +/- 13%, respectively).

CONCLUSIONS

High-intensity IE training is equally effective to moderately intense CLE training in inducing peripheral muscle adaptations; however, IE is associated with fewer training symptoms.

Effect of percutaneous endoscopic gastrostomy on gastro-esophageal reflux in mechanically-ventilated patients

AIM: To investigate the effect of percutaneous endoscopic gastrostomy (PEG) on gastroesophageal reflux (GER) in mechanically-ventilated patients.

METHODS: In a prospective, randomized, controlled study 36 patients with recurrent or persistent ventilator-associated pneumonia (VAP) and GER > 6% were divided into PEG group (n = 16) or non-PEG group (n  = 20). Another 11 ventilated patients without reflux (GER < 3%) served as control group. Esophageal pH-metry was performed by the “pull through” method at baseline, 2 and 7 d after PEG. Patients were strictly followed up for semi-recumbent position and control of gastric nutrient residue.

RESULTS: A significant decrease of median (range) reflux was observed in PEG group from 7.8 (6.2 - 15.6) at baseline to 2.7 (0 - 10.4) on d 7 post-gastrostomy (P < 0.01), while the reflux increased from 9 (6.2 - 22) to 10.8 (6.3 - 36.6) (P < 0.01) in non-PEG group. A significant correlation between GER (%) and the stay of nasogastric tube was detected (r = 0.56, P < 0.01).

CONCLUSION: Gastrostomy when combined with semi-recumbent position and absence of nutrient gastric residue reduces the gastroesophageal reflux in ventilated patients.

Sex chromosome abnormalities in bladder cancer: Y polysomies are linked to PT1-grade III transitional cell carcinoma

BACKGROUND

Bladder cancer is a heterogeneous group of tumors from both the biological and clinical points of view. Conventional cytogenetics and molecular genetic techniques have shown non-random aberrations in bladder cancer, while certain chromosomal changes have been found to be highly correlated with tumor grade or stage. The aim of this study was to evaluate, by fluorescence in situ hybridization (FISH), the numerical aberrations of chromosomes X and Y in bladder cancer, comparing the incidence of nuclei with aneusomies in different grades or histological stages of the tumors.

MATERIALS AND METHODS

The FISH technique, using DNA probes specific for chromosomes X and Y, was applied to 35 male bladder tumor specimens directly processed for cytogenetic study.

RESULTS

Polysomies of chromosome X were observed in 25 out of the 35 cases examined (71.43%), while numerical aberrations of chromosome Y were observed in 22 out of the 35 cases (62.86%). Of those cases with numerical aberrations of chromosome Y, 13 had polysomy (37.14%), while in 9 cases, loss of Y was observed (25.71%). Statistical analysis showed that numerical aberrations on chromosomes X or Y were not linked to histological stage, while a probable correlation was observed between aneusomies X or Y and tumor grade. Comparing the results of PT1-grade III tumors with those of PT1-grade II, statistical analysis showed that aneusomies Y and, especially, polysomy Y were correlated with PT1-grade III tumors, p = 0.023 and p = 0.010, respectively. An uncertain correlation between polysomy X and PT1-grade III tumors was found, p = 0.070.

CONCLUSION

Our results may suggest that the genetic instability associated with PT1-grade III tumors may account for the considerable potential for aggression of these tumors. However, to draw definite conclusions, a large number of cases must be studied.

Does soluble triggering receptor expressed on myeloid cells-1 play any role in the pathogenesis of septic shock?

In order to define the significance of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) upon progression from sepsis or severe sepsis to septic shock a prospective study was designed with 90 enrolled patients with septic syndrome due to ventilator-associated pneumonia. Blood was sampled on seven consecutive days upon initiation of symptoms and concentrations of tumour necrosis factor-alpha (TNFalpha), interleukin-6 (IL-6), IL-8 and sTREM-1 were estimated in serum by an enzymeimmunoassay. No differences in concentrations of TNFalpha, IL-6 and IL-8 were found between patients with sepsis, severe sepsis and septic shock on the first day of presentation of symptoms. Patients presenting with septic shock had concentrations of sTREM-1 significantly higher than both patients with sepsis and severe sepsis on the first day; no difference was found between patients with sepsis and severe sepsis. A positive correlation was detected between sTREM-1 and the white blood cell count. Serum levels of sTREM-1 were significantly lower in patients where VAP resolved compared to those where VAP did not resolve; similar findings were noted between patients who eventually survived and those who died. IL-6 followed the kinetics of sTREM-1 in correlation to patients's prognosis; levels of TNFalpha and IL-8 were unrelated to prognosis. It is concluded that sTREM-1 is particularly increased upon evolution from sepsis or severe sepsis to septic shock. Its sustained increase is an indication of poor outcome. The underlined pathophysiological role of sTREM-1 for the transition from sepsis or severe sepsis to septic shock might constitute a novel target for immunomodulatory therapy.

Relationship of BAL and lung tissue CD4+ and CD8+ T lymphocytes, and their ratio in idiopathic pulmonary fibrosis

BACKGROUND

Surgical biopsy specimens have shown that T lymphocytes (TLs) infiltrate lung parenchyma in patients with idiopathic pulmonary fibrosis (IPF) and might play a pathogenetic role. BAL, a far less invasive technique, has also been used for the investigation of IPF pathogenesis. However, controversy exists whether the BAL fluid cellular profile reflects the cellular composition of the lung parenchyma.

STUDY OBJECTIVE

To compare infiltrating TLs subpopulations (CD4+, CD8+, and CD4+/CD8+ ratio) in lung tissue and BAL fluid.

PATIENTS AND METHODS

Immunohistochemistry was performed according to the streptavidin-biotin method on the surgical biopsy specimens of 12 untreated patients with IPF. The number of CD3+, CD4+, and CD8+ TLs was determined by observer-interactive computerized image analysis (SAMBA microscopic image processor; Meylan, France). In BAL fluid, the same TLs subpopulations were evaluated by flow cytometry.

RESULTS

In lung tissue, CD3+ TLs accounted for a mean (+/- SEM) of 28.8 +/- 7% of total cells, CD4+ TLs accounted for 14.5 +/- 4% of total cells (50.1 +/- 4% of CD3+ TLs), and CD8+ TLs accounted for 13.8 +/- 4% of total cells (47.4 +/- 4% of CD3+ TLs). In BAL fluid, lymphocytes accounted for 9.8 +/- 2.5% of total cells, CD4+ TLs accounted for 51.8 +/- 4% of CD3+ TLs, and CD8+ TLs accounted for 42.2 +/- 4% of CD3+ TLs. Tissue CD4+ and CD8+ TLs (expressed as a percentage of CD3+ TLs) correlated significantly with the number of CD4+ and CD8+ TLs in BAL fluid (r = 0.846 and p = 0.001 vs r = 0.692 and p = 0.013, respectively). A significant positive correlation was also found between the mean CD4+/CD8+ ratio found in tissue and BAL fluid (1.05 +/- 0.21 and 1.5 +/- 0.27, respectively; r = 0.832; p = 0.01).

CONCLUSION

The results suggest that in patients with IPF, the TL subpopulations in BAL fluid reflect the pattern of lymphocytic infiltration in pulmonary parenchyma.

Static pressure volume curves and body posture in acute respiratory failure

OBJECTIVE

In acute respiratory distress syndrome the body posture effects on pressure-volume (PV) curves are still unclear. We examined the effects of prone position on inflation PV curves and their potential relationships with postural alterations in gas exchange.

DESIGN AND SETTING

Prospective study with patients serving as their own controls in a university-affiliated 30-bed intensive care unit.

PATIENTS AND PARTICIPANTS

Thirteen anesthetized, paralyzed, semirecumbent, mechanically ventilated patients with early/severe/diffuse ARDS.

INTERVENTIONS

Sequential body posture changes: preprone semirecumbent, prone, and postprone semirecumbent.

MEASUREMENTS AND RESULTS

In each posture hemodynamics, gas exchange, and lung volumes were determined before/during removal and after restoration of positive end-expiratory pressure (PEEP=10.2+/-0.6 cmH2O). At zero PEEP PV curves of respiratory system, lung, and chest wall were constructed. Prone position vs. preprone semirecumbent resulted in significantly reduced pressure at lower inflection point of lung PV curve (2.2+/-0.2 vs. 3.7+/-0.5 cmH2O) and increased volume at upper inflection point (0.87+/-0.03 vs. 0.69+/-0.05 l). Postural reduction in lower inflection point pressure of lung PV curve was the sole independent predictor of pronation-induced increases in PaO2/FIO2 (R2=0.76). PaO2/FIO2 increases were also significantly related with increases in functional residual capacity (R2=0.60).

CONCLUSIONS

In early/severe/diffuse ARDS prone position reduces lower inflection point pressure and increases upper inflection point UIP volume of the lung PV curve. Lower inflection point pressure reductions explain oxygenation improvements, which are also associated with a postural increase in functional residual capacity.

Differential cardiovascular responses during weaning failure: effects on tissue oxygenation and lactate

OBJECTIVE

To test the following two hypotheses during weaning failure: (a) mixed venous oxygen saturation (SvO2) does not decrease in patients whose oxygen consumption does not increase, and (b) blood lactate may increase in patients who demonstrate substantial decreases in SvO2.

DESIGN AND SETTING

A prospective observational and physiological study in a 30-bed university intensive care unit.

PATIENTS AND PARTICIPANTS

18 patients who failed weaning and 12 patients who succeeded weaning (controls).

MEASUREMENTS AND RESULTS

Hemodynamics, global tissue oxygenation, cardiovascular response (cardiac index/oxygen extraction diagram), and blood lactate were measured in ventilator-supported patients undergoing a spontaneous breathing trial. In patients who failed without having increased their oxygen consumption (n=9) the increase in oxygen delivery was accompanied by a decrease in oxygen extraction (by 15+/-4%). In patients who failed (n=9) having increased their oxygen consumption (by>10%) this increase was met mainly by an increase in oxygen extraction (by 30+/-7%). SvO2 increased by 2+/-1% in the former patients, whereas it decreased by 20+/-5% in the latter. Arterial lactate increased (range 2.3-3.1 mM/l) in only three patients who failed to have increased oxygen consumption and exhibited heart failure and the highest decreases in SvO2 (by 12-39%).

CONCLUSIONS

Patients whose SvO2 does not decrease during weaning failure do not have increased oxygen consumption probably due to respiratory center depression in some of them. Patients whose SvO2 decreases have increased oxygen consumption.

The effects of nebulized salbutamol, external positive end-expiratory pressure, and their combination on respiratory mechanics, hemodynamics, and gas exchange in mechanically ventilated chronic obstructive pulmonary disease patients

We hypothesized that combined salbutamol and external positive end-expiratory pressure (PEEPe) may present additive benefits in chronic obstructive pulmonary disease (COPD) exacerbation. In 10 anesthetized, mechanically ventilated, and bronchodilator-responsive COPD patients exhibiting moderate intrinsic PEEP (PEEPi), we assessed respiratory system (rs) mechanics, hemodynamics, and gas exchange at (a) baseline (zero PEEPe [ZEEPe]), (b) 30 min after 5 mg of nebulized salbutamol administration (ZEEPe-S), (c) 30 min after setting PEEPe at baseline PEEPi level (PEEPe), and (d) 30 min after 5 mg of nebulized salbutamol administration with PEEPe maintained unchanged (PEEPe-S). Return of determined variable values to baseline values was confirmed before PEEPe application. Relative to ZEEPe, (a) at ZEEP-S, PEEPi (4.8 +/- 0.7 versus 7.0 +/- 1.1 cm H(2)O), functional residual capacity change (115.6 +/- 23.1 versus 202.1 +/- 46.0 mL), minimal rs (airway) resistance (9.3 +/- 1.4 versus 11.8 +/- 2.2 cm H(2)O.L(-1).s(-1)), and additional rs resistance (5.2 +/- 1.4 versus 7.2 +/- 1.3 cm H(2)O.L(-1).s(-1)) were reduced (P < 0.01), and hemodynamics were improved; (b) at PEEPe, PEEPi (3.7 +/- 1.3 cm H(2)O) was reduced (P < 0.01), and gas exchange was improved; and (c) at PEEPe-S, PEEPi (2.0 +/- 1.2 cm H(2)O) was minimized, and rs mechanics (static rs elastance included), hemodynamics, and gas exchange were improved. Conclusively, in carefully preselected COPD patients, bronchodilation/PEEPe exhibits additive benefits.

Soluble guanylyl cyclase expression is reduced in allergic asthma

Soluble guanylyl cyclase (sGC) is an enzyme highly expressed in the lung that generates cGMP contributing to airway smooth muscle relaxation. To determine whether the bronchoconstriction observed in asthma is accompanied by changes in sGC expression, we used a well-established murine model of allergic asthma. Histological and biochemical analyses confirmed the presence of inflammation in the lungs of mice sensitized and challenged with ovalbumin (OVA). Moreover, mice sensitized and challenged with OVA exhibited airway hyperreactivity to methacholine inhalation. Steady-state mRNA levels for all sGC subunits (alpha1, alpha2, and beta1) were reduced in the lungs of mice with allergic asthma by 60-80%, as estimated by real-time PCR. These changes in mRNA were paralleled by changes at the protein level: alpha1, alpha2, and beta1 expression was reduced by 50-80% as determined by Western blotting. Reduced alpha1 and beta1 expression in bronchial smooth muscle cells was demonstrated by immunohistochemistry. To study if sGC inhibition mimics the airway hyperreactivity seen in asthma, we treated naïve mice with a selective sGC inhibitor. Indeed, in mice receiving ODQ the methacholine dose response was shifted to the left. We conclude that sGC expression is reduced in experimental asthma contributing to the observed airway hyperreactivity.

CD8+ T lymphocytes in lung tissue from patients with idiopathic pulmonary fibrosis

Background

Several studies have implicated a role of inflammation in the pathogenesis of lung damage in idiopathic pulmonary fibrosis (IPF). Parenchymal lung damage leads to defects in mechanics and gas exchange and clinically manifests with exertional dyspnea. Investigations of inflammatory cells in IPF have shown that eosinophils, neutrophils and CD₈₊ TLs may be associated with worse prognosis. We wished to investigate by quantitative immunohistochemistry infiltrating macrophages, neutrophils and T lymphocytes (TLs) subpopulations (CD₃₊, CD₄₊ and CD₈₊) in lung tissue of patients with IPF and their correlation with lung function indices and grade of dyspnoea.

Methods

Surgical biopsies of 12 patients with IPF were immunohistochemically stained with mouse monoclonal antibodies (anti-CD₆₈ for macrophages, anti-elastase for neutrophils, and anti-CD₃, anti-CD₄, anti-CD₈ for CD₃₊TLs, CD₄₊TLs, and CD₈₊TLs respectively). The number of positively stained cells was determined by observer-interactive computerized image analysis (SAMBA microscopic image processor). Cell numbers were expressed in percentage of immunopositive nuclear surface in relation to the total nuclear surface of infiltrative cells within the tissue (labeling Index). Correlations were performed between cell numbers and physiological indices [FEV₁, FVC, TLC, DLCO, PaO₂, PaCO₂ and P(A-a)O₂)] as well as dyspnoea scores assessed by the Medical Research Council (MRC) scale.

Results

Elastase positive cells accounted for the 7.04% ± 1.1 of total cells, CD₆₈₊ cells for the 16.6% ± 2, CD₃₊ TLs for the 28.8% ± 7, CD₄₊ TLs for the 14.5 ± 4 and CD₈₊ TLs for the 13.8 ± 4. CD₈₊TLs correlated inversely with FVC % predicted (r_s = -0.67, p = 0.01), TLC % predicted (r_s = -0.68, p = 0.01), DLCO % predicted (r_s = -0.61, p = 0.04), and PaO₂ (r_s = -0.60, p = 0.04). Positive correlations were found between CD₈₊TLs and P(A-a)O₂ (r_s = 0.65, p = 0.02) and CD₈₊TLs and MRC score (r_s = 0.63, p = 0.02). Additionally, CD₆₈₊ cells presented negative correlations with both FVC % predicted (r_s = -0.80, p = 0.002) and FEV₁ % predicted (r_s = -0.68, p = 0.01).

Conclusion

In UIP/IPF tissue infiltrating mononuclear cells and especially CD₈₊ TLs are associated with the grade of dyspnoea and functional parameters of disease severity implicating that they might play a role in its pathogenesis.

Interaction between the 90-kDa heat shock protein and soluble guanylyl cyclase: physiological significance and mapping of the domains mediating binding

The 90-kDa heat shock protein (hsp90) regulates the stability and function of many client proteins, including members of the NO-cGMP signaling pathway. Soluble guanylyl cyclase (sGC), an NO receptor, was recently reported to be an hsp90-interacting partner. In the present study, we show that hsp90 binds to both subunits of the most common sGC form (alpha(1)beta(1)) when these are expressed individually but only interacts with beta(1) in the heterodimeric form of the enzyme. Characterization of the region of hsp90 required to bind each subunit in immunoprecipitation experiments revealed that residues 310 to 456 of hsp90 interact with the sGC subunits. The region of beta(1) responsible for binding to hsp90beta was mapped using in vitro binding assays and immunoprecipitation experiments and was found to lie in the regulatory domain. The physiological importance of the hsp90/sGC interaction was investigated by treating rat smooth muscle cells with the hsp90 inhibitors radicicol and geldanamycin (GA) and determining both sGC activity and protein levels. Long-term (24 or 48 h) inhibition of hsp90 resulted in a strong decrease of both alpha(1) and beta(1) protein levels and sGC activity. Moreover, incubation of smooth muscle cells with the proteasome inhibitor N-benzoyloxycarbonyl (Z)-Leu-Leu-leucinal (MG132) blocked the GA-induced down-regulation of sGC. We conclude that the N-terminal region of the beta(1) subunit mediates binding of the heterodimeric form of sGC to hsp90 and that this interaction involves the M domain of hsp90. Hsp90 binding to sGC regulates the pool of active enzymes by affecting the protein levels of the two subunits.

Prone position reduces lung stress and strain in severe acute respiratory distress syndrome

The present authors hypothesised that in severe acute respiratory distress syndrome (ARDS), pronation may reduce ventilator-induced overall stress (i.e. transpulmonary pressure (P(L))) and strain of lung parenchyma (i.e. tidal volume (V(T))/end-expiratory lung volume (EELV) ratio), which constitute major ventilator-induced lung injury determinants. The authors sought to determine whether potential pronation benefits are maintained in post-prone semirecumbent (SR(PP)) posture under pressure-volume curve-dependent optimisation of positive end-expiratory pressure (PEEP). A total of 10 anesthetised/paralysed, mechanically ventilated (V(T) = 9.0+/-0.9 mL.kg(-1) predicted body weight; flow = 0.91+/-0.04 L.s(-1); PEEP = 9.4+/-1.3 cmH(2)O) patients with early/severe ARDS were studied in pre-prone semirecumbent (SR(BAS)), prone, and SR(PP) positions. Partitioned respiratory mechanics were determined during iso-flow (0.91 L.s(-1)) experiments (V(T) varied within 0.2-1.0 L), along with haemodynamics, gas exchange, and EELV. Compared with SR(BAS), pronation/SR(PP) resulted in reduced peak/plateau P(L) at V(T)s> or =0.6 L; static lung elastance and additional lung resistance decreased and chest wall elastance (in prone position) increased; EELV increased (23-33%); V(T)/EELV decreased (27-33%); arterial oxygen tension/inspiratory oxygen fraction and arterial carbon dioxide tension improved (21-43/10-14%, respectively), and shunt fraction/physiological dead space decreased (21-50/20-47%, respectively). In early/severe acute respiratory distress syndrome, pronation under positive end-expiratory pressure optimisation may reduce ventilator-induced lung injury risk. Pronation benefits may be maintained in post-prone semirecumbent position.

Non-random structural chromosomal changes in primary gastric cancer

Gastric cancer is of major importance world-wide representing the second most common cause of cancer related death in the world. Data concerning the chromosomal changes in gastric cancer are limited and no specific change has been identified to date. We have studied cytogenetically 15 cases of primary gastric cancer by direct culture of tumors cells and G-banding technique. We focused on structural aberrations observed in order to identify non-random aberrations presenting common chromosomal breakpoints. Chromosomes most commonly involved were according to frequency 1,11,14,7,17,6,8 and 13. Chromosome 11 was involved as add(11)(p15), while the pericentromeric area of chromosome 14 was constantly participated in aberrations. Isochromosomes i(1q), i(8q), i(13q), i(14q) and i(17q) were constantly found. Furthermore translocations t(1;7), t(7;14), t(6;17) and t(5;14) were identified. Conventional cytogenetics continues to be valuable in cancer study detecting genomic areas potentially candidate for the isolation of genes related to carcinogenesis.

Patterns of dynamic hyperinflation during exercise and recovery in patients with severe chronic obstructive pulmonary disease

BACKGROUND

Not all patients with severe chronic obstructive pulmonary disease (COPD) progressively hyperinflate during symptom limited exercise. The pattern of change in chest wall volumes (Vcw) was investigated in patients with severe COPD who progressively hyperinflate during exercise and those who do not.

METHODS

Twenty patients with forced expiratory volume in 1 second (FEV(1)) 35 (2)% predicted were studied during a ramp incremental cycling test to the limit of tolerance (Wpeak). Changes in Vcw at the end of expiration (EEVcw), end of inspiration (EIVcw), and at total lung capacity (TLCVcw) were computed by optoelectronic plethysmography (OEP) during exercise and recovery.

RESULTS

Two significantly different patterns of change in EEVcw were observed during exercise. Twelve patients had a progressive significant increase in EEVcw during exercise (early hyperinflators, EH) amounting to 750 (90) ml at Wpeak. In contrast, in all eight remaining patients EEVcw remained unchanged up to 66% Wpeak but increased significantly by 210 (80) ml at Wpeak (late hyperinflators, LH). Although at the limit of tolerance the increase in EEVcw was significantly greater in EH, both groups reached similar Wpeak and breathed with a tidal EIVcw that closely approached TLCVcw (EIVcw/TLCVcw 93 (1)% and 93 (3)%, respectively). EEVcw was increased by 254 (130) ml above baseline 3 minutes after exercise only in EH.

CONCLUSIONS

Patients with severe COPD exhibit two patterns during exercise: early and late hyperinflation. In those who hyperinflate early, it may take several minutes before the hyperinflation is fully reversed after termination of exercise.