Prediction of exercise respiratory limitation from pulmonary function tests

BACKGROUND

Evaluation of unexplained exercise intolerance is best resolved by cardiopulmonary exercise testing (CPET) which enables the determination of the exercise limiting system in most cases. Traditionally, pulmonary function tests (PFTs) at rest are not used for the prediction of a respiratory limitation on CPET.

OBJECTIVE

We sought cut-off values on PFTs that might, a priori, rule-in or rule-out a respiratory limitation in CPET.

METHODS

Patients who underwent CPET in our institute were divided into two groups according to spirometry: obstructive and non-obstructive. Each group was randomly divided 2:1 into derivation and validation cohorts respectively. We analyzed selected PFTs parameters in the derivation groups in order to establish maximal and minimal cut-off values for which a respiratory limitation could be ruled-in or ruled-out. We then validated these values in the validation cohorts.

RESULTS

Of 593 patients who underwent a CPET, 126 were in the obstructive and 467 in the non-obstructive group. In patients with obstructive lung disease, forced expiratory volume in 1 second (FEV1) ≥ 61% predicted could rule out a respiratory limitation, while FEV1 ≤ 33% predicted was always associated with a respiratory limitation. For patients with non-obstructive spirometry, FEV1 of ≥ 73% predicted could rule-out a respiratory limitation. Application of this algorithm might have saved up to 47% and 71% of CPETs in our obstructive and non-obstructive groups, respectively.

CONCLUSION

Presence or absence of a respiratory limitation on CPET can be predicted in some cases based on a PFTs performed at rest.

Tube thoracostomy during allogeneic stem cell transplantation does not carry an increased risk for infections or bleeding

BACKGROUND

Candidates for stem cell transplantation may occasionally suffer from massive pleural effusions related to their disease and require tube thoracostomy. The additional risk of this procedure during allogeneic transplantation procedure is not known.

METHODS

Four high-risk patients transplanted in our institution during a 2-yr period had chest drainage by tube thoracostomy. The characteristics of the fluid, the clinical course, and the outcome were assessed.

RESULTS

A total of nine chest drains were inserted (range 1-5). No bleeding complications related to the procedure were noted. None of the patients developed any clinical signs of local infection at the tube insertion site or within the pleural fluid. All cultures taken from the drained fluid or from the insertion wound were negative.

CONCLUSIONS

Tube thoracostomy in itself does not seem to pose additional risks in the transplant procedure, despite all patients in this series being considered to be at high-risk for complications.

Time course of bleomycin-induced lung fibrosis

Intratracheal instillation (IT) of bleomycin is a widely used experimental model for lung fibrosis. In this study we describe the time-course of bleomycin-induced lung fibrosis in mice using computer-assisted morphometry. C57Bl/6J mice were treated with a single IT dose of bleomycin or control saline. Animals were killed 3, 6, 14 and 21 days post-IT. Lung injury was evaluated by analysis of bronchoalveolar lavage (BAL) fluid, hydroxyproline concentration in the lung, routine light microscopic examination resulting in a semiquantitative morphological index (SMI) of lung injury, and quantitative morphological measurements (fibrosis fraction and alveolar wall area fraction) aided by optimas image analysis software. Changes in BAL fluid attributed to bleomycin treatment include increased total cell count (days 14 and 21), and increased percentage of neutrophils (days 3 and 6) followed by a sustained increase in lymphocytes (days 6, 14 and 21). Hydroxyproline levels increased in bleomycin-treated mice on days 14 and 21. Median SMI grades were significantly elevated on days 3, 14 and 21. Computer-assisted morphometry demonstrated a 3-fold increase in fibrosis fraction and a 1.3-fold increase in wall area fraction in bleomycin-treated mice on day 14, with no further increase on day 21. These data also demonstrate that the most suitable time point for assessing lung fibrosis in this model is 14 days after IT instillation of bleomycin, based on the observation that at 14 days the animals developed extensive fibrosis, but had less variability in the fibrotic response and lower mortality than later at 21 days. Computer-assisted morphometry provides objective and quantitative measurements that are a useful tool for the evaluation of bleomycin-induced lung injury.

All-trans-retinoic acid (ATRA) is of no benefit in bleomycin-induced lung injury

All-trans-retinoic acid (ATRA) has anti-fibrotic and antiinflammatory properties, and may be useful as a therapeutic agent in lung fibrosis. To test this hypothesis we investigated the effect of ATRA on bleomycin-induced lung fibrosis in Sprague-Dawley rats. Treatment groups included: (1) a single intratracheal (i.t.) instillation of bleomycin and daily intraperitoneal (i.p.) injection of 0.5 mg/kg per day ATRA; (2) i.t. bleomycin and i.p. ATRA, 2 mg/kg per day, (3) i.t. bleomycin and i.p. diluent (cottonseed oil); (4) i.t. saline and i.p. ATRA, 0.5 mg/kg per day, (5) i.t. saline and i.p. ATRA, 2 mg/kg per day; and (6) i.t. saline and i.p. diluent. Animals were studied 14 days after i.t. instillation. Lung injury was evaluated by total and differential cell count in bronchoalveolar lavage fluid, by a semi-quantitative morphological index of lung injury, and by biochemical analysis of lung hydroxyproline content. Overt signs of lung injury were apparent in bleomycin-treated rats by all measures. These changes were not affected by treatment with ATRA at either dose. This study does not support the use of ATRA to prevent or ameliorate lung fibrosis.

Lymphokines in bleomycin-induced lung injury in bleomycin-sensitive C57BL/6 and -resistant BALB/c mice

To study the pattern of lymphokines in bleomycin-induced lung injury, T cells were isolated from lung interstitial tissue (LIL), peribronchial lymphatic tissue (PBLT), and bronchoalveolar lavage (BAL) fluid of bleomycin-"sensitive" C57Bl/6 and bleomycin-"resistant" BALB/c mice at 3, 6, and 14 days following intratracheal instillation of bleomycin or saline. After 48 hours in culture, conditioned media were collected and assayed with specific enzyme-linked immunosorbent assay (ELISA) for interferon (IFN)-gamma, interleukin (IL)-2, IL-4 and IL-5. In bleomycin-treated C57B1/6 mice, IFN-gamma production was increased up to 20-fold at 3 and 6 days in LIL, and at 3 days in PBLT lymphocytes. IL-4 production was slightly decreased in LIL and PBLT lymphocytes at 14 days. IL-2 and IL-5 were not changed by bleomycin. In BALB/c mice, IFN-gamma production was increased 5-fold at 14 days, and IL-2 production at 6 days, in LIL but not PBLT. IL-4 and IL-5 were not significantly changed. The increase in IFN-gamma may play a role in the pathogenesis of bleomycin-induced lung injury. Differences in the cytokine pattern between the strains of mice may contribute to the variable strain susceptibility in bleomycin-induced lung injury.

Geographic variance in the frequency of the t(14;18) translocation in follicular lymphoma: an Israeli series compared to the world

It has been suggested that differences in the frequency of the t(14;18) translocation in follicular lymphoma might explain ethno-geographic variation in the incidence of these tumors. We tested Israeli follicular lymphoma patients for the frequency of the t(14;18) translocation, and reviewed the published literature, comparing the frequency in our series with data from different parts of the world. Tissue specimens from 36 Israeli follicular lymphoma patients were tested for presence of the translocation by PCR amplification of the MBR breakpoint. Twenty-two of the 36 patients (61%) tested positive. A systematic search of the literature yielded 35 papers reporting the frequency of the t(14;18) translocation in follicular lymphoma. We analyzed cytogenetic data and molecular data separately. For each method, data were pooled from all studies within each of three geographical regions - USA, East Asia and Europe. Pooled data from cytogenetic studies show a low frequency of the translocation in the Far East (38%) compared to the USA (71%), with an intermediate frequency found in Europe (61%). Molecular studies show a similar frequency of the translocation in the Far East and Europe, significantly lower than the frequency in pooled data from American studies. The frequency in our Israeli series is relatively high, comparable to that detected in the USA. We suggest that the apparent geographical differences we describe are unlikely to be caused by a difference in the biology of the tumor, and are more likely due to technical and methodological factors. We conclude that it is unlikely that differences in the frequency of the t(14;18) translocation explain the difference in the epidemiology of lymphoma between East and West.