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Biomedical subjects

Richard W Light

Publications and source records attributed to Richard W Light.

At least 55 records · Page 3Linked to original sources
PubMed2004

A new radiologic appearance of pulmonary thromboembolism: multiloculated pleural effusions.

The objective of this study was to describe the clinical course and response to treatment of five patients who developed loculated pleural effusions as complications of pulmonary thromboembolism (PTE). The clinical charts of five patients who had loculated pleural effusions in the course of their PTE were reviewed, with special attention paid to the duration of symptoms before diagnosis, the pleural fluid analysis findings, and the response of the loculations to anticoagulant therapy. In a tertiary care academic medical center, the five patients described in the present study had multiple locules of pleural fluid seen on chest radiographs and thoracic CT scans. In all cases, the diagnosis of PTE had been delayed for at least 2 weeks after symptoms developed. The loculated pleural fluid had led to the mistaken diagnosis of empyema in three cases. The pleural fluid in all cases was exudative, with a predominance of lymphocytes. With anticoagulant therapy, the loculations largely disappeared within the first few days of therapy. Although most pleural effusions secondary to PTE are relatively small and free-flowing, this study demonstrates that PTE can lead to loculated pleural effusions. The loculations occurred in patients who had been symptomatic from their PTE for > 2 weeks. In each instance, the pleural fluid was a lymphocytic exudate. The effusions rapidly resolved with the institution of anticoagulant therapy. PTE should be included in the differential diagnosis of a loculated pleural effusion, particularly if the pleural fluid contains predominantly lymphocytes.

Adult↗
PubMed2004

Stability of adenosine deaminase during transportation.

STUDY OBJECTIVE: Measurement of pleural fluid adenosine deaminase (ADA) levels is useful in the differential diagnosis of pleural effusions. However, at ambient temperatures, the levels of this enzyme decline with time. The purpose of the present study was to identify, test, and optimize additives that stabilize ADA, consequently eliminating the need for dry ice or other cold specimen transport media. DESIGN: A preliminary screen of historically proven stabilizing agents for specific proteins demonstrated effectiveness of glycerol for maintenance of pleural fluid ADA levels. Systematic studies for exploitation of the glycerol effect included the following: (1) supplements to the glycerol of promising alternate compounds, (2) long-term stability studies at ambient and elevated temperatures, (3) a field test of an effective mixture as a means for reduction of specimen transport costs, (4) thermal stability studies for optimization of the agents for use at otherwise denaturing temperatures, and (5) inclusion of pleural fluids from patients with a variety of etiologies, including tuberculous pleurisy, in order to gauge the effectiveness of the stabilizing agents on both the high and low molecular weight forms of ADA. RESULTS: A mixture of glycerol and ethylene glycol, each at 5% concentration, maintained pleural fluid ADA levels for at least 21 days at both room temperatures and 37 degrees C. A field test of 32 pleural fluids found that ADA levels in specimens containing this mixture, sent to the laboratory by surface mail at ambient temperatures, were nearly identical to those in aliquots of the same fluids shipped over dry ice. The bias in the measurement was 0.49 IU/L, with a precision of 2.49 IU/L. The correlation coefficient between the two measurements was 0.97. Thermal stability studies found that tuberculous pleural fluids containing 10% glycerol and 0.10 mol/L sodium sulfate maintained constant ADA levels for at least 10 days at 45 degrees C, an otherwise denaturing temperature for nonstabilized specimens. CONCLUSION: The addition of stabilizing agents to pleural fluid specimens allows the transport of those specimens to distant laboratories at ambient temperatures without a decline in the ADA levels. Employment of those agents will decrease the cost of the test and facilitate its use in second- and third-world countries.

Adenosine Deaminase↗
PubMed2003

Eosinophilic pleural effusions.

Eosinophilic pleural effusions, defined as a pleural effusion that contains at least 10% eosinophils, may be caused by almost every condition that can cause pleural disease. Eosinophilic pleural effusion occurs most commonly during conditions associated with the presence of blood or air in the pleural space, infections, and malignancy. Drug-induced pleural effusions, pleural effusions accompanying pulmonary embolism, and benign asbestos pleural effusions are also among the common causes of eosinophilic pleural effusion. No etiology is found in as many as one third of patients. Because studies evaluating different diagnostic approaches with eosinophilic pleural effusions are lacking, the authors suggest that certain noninvasive and invasive diagnostic tools must be used based on the patient's clinical characteristics.

Eosinophilia↗
PubMed2003

Pleural space as a site of ectopic gene delivery: transfection of pleural mesothelial cells with systemic distribution of gene product.

STUDY OBJECTIVES: Successful ectopic gene therapy requires the transfection of the cells at the ectopic site, with local and systemic delivery of the gene product. This study aimed to evaluate the pleural mesothelial surface as a potential site for ectopic gene therapy. DESIGN: A secreted placental alkaline phosphatase (PALP) plasmid was injected bilaterally into the pleural spaces of seven rabbits via a chest tube, while an irrelevant reporter plasmid was injected into seven control rabbits. Blood was collected at baseline and at 24, 48, and 72 h after the injections. Pleural fluid was collected by lavage at 24, 48, and 72 h after the injections. The PALP level was measured by chemiluminesence. MEASUREMENTS AND RESULTS: Significant expressions of PALP proteins were observed in the serum of the treatment rabbits, with a threefold increase over baseline at 24 h, a ninefold increase at 48 h, and a twofold increase at 72 h. The serum PALP levels in the control rabbits remained at baseline levels at all time points. The pleural fluid PALP levels peaked at 24 h and decreased over the next 72 h. Mimicking the in vivo pattern, pleural mesothelial cells transfected in vitro demonstrated a similar increase in PALP levels. CONCLUSIONS: The results of the present short-term pilot study suggest that pleural mesothelial cells can be successfully transfected with plasmids, with increases in both the local and systemic levels of the gene product. The pleural space should be further evaluated for ectopic gene therapy.

Alkaline Phosphatase↗
PubMed2003

Ultrasound-guided thoracentesis: is it a safer method?

STUDY OBJECTIVES: The objectives of this study are as follows: (1) to determine the incidence of complications from thoracentesis performed under ultrasound guidance by interventional radiologists in a tertiary referral teaching hospital; (2) to evaluate the incidence of vasovagal events without the use of atropine prior to thoracentesis; and (3) to evaluate patient or radiographic factors that may contribute to, or be predictive of, the development of re-expansion pulmonary edema after ultrasound-guided thoracentesis. DESIGN: Prospective descriptive study. SETTING: Saint Thomas Hospital, a tertiary referral teaching hospital in Nashville, TN. PATIENTS: All patients referred to interventional radiology for diagnostic and/or therapeutic ultrasound-guided thoracentesis between August 1997 and September 2000. RESULTS: A total of 941 thoracenteses in 605 patients were performed during the study period. The following complications were recorded: pain (n = 25; 2.7%), pneumothorax (n = 24; 2.5%), shortness of breath (n = 9; 1.0%), cough (n = 8; 0.8%), vasovagal reaction (n = 6; 0.6%), bleeding (n = 2; 0.2%), hematoma (n = 2; 0.2%), and re-expansion pulmonary edema (n = 2; 0.2%). Eight patients with pneumothorax received tube thoracostomies (0.8%). When > 1,100 mL of fluid were removed, the incidence of pneumothorax requiring tube thoracostomy and pain was increased (p < 0.05). Fifty-seven percent of patients with shortness of breath during the procedure were noted to have pneumothorax on postprocedure radiographs, while 16% of patients with pain were noted to have pneumothorax on postprocedure radiographs. Vasovagal reactions occurred in 0.6% despite no administration of prophylactic atropine. Re-expansion pulmonary edema complicated 2 of 373 thoracenteses (0.5%) in which > 1,000 mL of pleural fluid were removed. CONCLUSIONS: The complication rate with thoracentesis performed by interventional radiologists under ultrasound guidance is lower than that reported for non-image-guided thoracentesis. Premedication with atropine is unnecessary given the low incidence of vasovagal reactions. Re-expansion pulmonary edema is uncommon even when > 1,000 mL of pleural fluid are removed, as long as the procedure is stopped when symptoms develop.

Chest Tubes↗
PubMed2003

Variations in pleural fluid WBC count and differential counts with different sample containers and different methods.

OBJECTIVE: To compare the results of pleural fluid analysis for WBC counts and differential cell counts as follows: (1) counting performed manually vs that performed by an automated cell counter; (2) cells collected in different types of specimen containers; and (3) cell counts performed at 4 and 24 h postthoracentesis. METHODS: Twenty-eight pleural fluid samples were each collected in five different containers (ie, ethylenediaminetetraacetic acid (EDTA)-treated glass, citrate-treated glass, heparinized glass, plain glass, and plain plastic tubes). The WBC counts and differential cell counts were obtained manually (on the EDTA tube) and with an automated counter on all tubes within 4 h of collection, and again after 24 h of refrigeration. RESULTS: There was a close correlation between the WBC counts obtained manually and those obtained with the automated counter from the pleural fluid samples collected in the EDTA tubes (r = 0.92). With the automated counter, the pleural fluid WBC counts were similar among the three tubes containing anticoagulants, but the counts obtained from the tubes without anticoagulants were significantly lower. The differential cell counts obtained manually and those obtained with the automated cell counter differed substantially. Although the percentage of lymphocytes was similar, the automated counter was inaccurate in differentiating neutrophils from large monocytes or mesothelial cells. The WBC counts obtained within 4 h of collection and 24 h after collection were virtually identical. CONCLUSIONS: The WBC counts obtained manually and with the automated counter from pleural fluid samples in EDTA tubes correlated very closely. The pleural fluid WBC count was lower if the pleural fluids had been collected in tubes without an anticoagulant. Automated WBC counts from pleural fluid specimens were inaccurate, possibly due to difficulty in separating neutrophils from monocyte/mesothelial cells. Refrigerated storage for up to 24 h had no significant effect on the total WBC count or on the WBC count differential regardless of the tube utilized.

Blood Specimen Collection↗
PubMed2003

Patient with bilateral pleural effusion: are the findings the same in each fluid?

STUDY OBJECTIVES: To determine whether, in patients with bilateral pleural effusions, the main cellular and biochemical features of the pleural fluid on the right side differ from or correlate with those on the left side. We examined lactate dehydrogenase (LDH), glucose, and total protein (TP) levels, RBC count, nucleated cell count (NCC), and differential cell count. PATIENTS AND METHODS: Twenty-seven patients with bilateral pleural effusions, including 13 patients with effusions after coronary artery bypass graft surgery, 12 patients with congestive heart failure, 1 patient with malignant pericarditis, and 1 patient with renal failure, were studied retrospectively. RESULTS: The right-sided and the left-sided pleural effusions did not differ in the mean TP (p = 0.38), glucose (p = 0.31), and LDH (p = 0.39) levels, RBC count (p = 0.31), NCC (p = 0.96), and the percentage of neutrophils (p = 0.22), lymphocytes (p = 0.73), mononuclear cells (MNCs) [p = 0.49], and eosinophils (p = 0.65). The bias +/- precision was 0.1 +/- 0.64 g/dL for TP, - 2.7 +/- 23 mg/dL for glucose, 41 +/- 362 IU/L for LDH, 6,100 +/- 62,900 cells/ micro L for RBC count, - 36 +/- 1,043 cells/ micro L for NCC, - 2.9 +/- 11.6% for the percentage of neutrophils, 1.15 +/- 17% for the percentage of lymphocytes, 2.3 +/- 17% for the percentage of the MNCs, and - 0.15 +/- 5.4% for the percentage of eosinophils. Moreover, there was a close correlation between the right-sided and the left-sided pleural effusions concerning TP level (r = 0.85, p < 0.001), glucose level (r = 0.78, p < 0.001), LDH level (r = 0.71, p < 0.001), RBC count (r = 0.66, p < 0.001), NCC (r = 0.60, p = 0.001), and the percentage of neutrophils (r = 0.77, p < 0.001), lymphocytes (r = 0.77, p < 0.001), MNCs (r = 0.74, p < 0.001), and eosinophils (r = 0.84, p < 0.001). CONCLUSION: Since the pleural fluid findings tend to be similar in both sides of patients with bilateral pleural effusion, we suggest that diagnostic thoracentesis may not need to be performed on both sides, unless there is a specific clinical indication.

Cell Count↗
PubMed2003

Pleurodesis practice for malignant pleural effusions in five English-speaking countries: survey of pulmonologists.

BACKGROUND: Pleurodesis is important in the management of malignant pleural effusions, but no consensus exists on the optimal agent or methods of pleurodesis. How pleurodesis is practiced worldwide has not been studied. OBJECTIVES: To identify variations in the clinical practice of pleurodesis in major English-speaking countries, and to quantify the experience of pulmonologists on the effectiveness and adverse effects of different pleurodesis agents worldwide. METHODS: Eight hundred fifty-nine pulmonologists practicing in the United States, United Kingdom, Canada, Australia, and New Zealand participated in a Web-based survey. RESULTS: The respondents collectively perform > 8,300 pleurodesis annually. Talc was the preferred agent by most respondents (slurry, 56%; poudrage, 12%), followed by tetracycline derivatives (26%), and bleomycin (7%). Differences were seen in pleurodesis practice patterns among practitioners among and within the surveyed countries. Physicians' overall satisfaction with the available pleurodesis agents was modest (5.0 out of 8), and the reported success rate averaged only 66%. Talc (both poudrage and slurry) was perceived as significantly more effective, but was associated with significantly more pain, nausea, and fever (p < 0.05). Respiratory failure occurred more commonly with talc poudrage than with other agents (p < 0.05), and had been observed by 70% and 54% of physicians who used talc poudrage and slurry, respectively. CONCLUSIONS: Significant variations exist in how pleurodesis is performed worldwide. Pleurodesis agents currently available are perceived as suboptimal. Talc poudrage and slurry were perceived to be more effective, but were associated with more complications, including respiratory failure.

Adult↗
PubMed2003

Assessing need for long-term oxygen therapy: a comparison of conventional evaluation and measures of ambulatory oximetry monitoring.

BACKGROUND: Appropriate identification of hypoxic patients with chronic obstructive pulmonary disease (COPD) is important because of the demonstrated survival benefit of long-term oxygen therapy (LTOT) and its associated cost. Resting oxygen saturation (measured via pulse oximetry [S(pO2)]) and lowest exercise S(pO2) (during a 6-min walk test) is the standard method of determining LTOT requirements, but that method does not measure the patient's oxygenation during sleep or activities of daily living. We hypothesized that values obtained via the standard method would correlate poorly with values obtained via ambulatory oximetry monitoring. METHODS: We conducted a prospective, cohort study in an out-patient pulmonary clinic in a tertiary care referral center, with 20 stable COPD patients who were being evaluated for LTOT with conventional evaluation versus 16-24 hours of ambulatory oximetry. RESULTS: The resting S(pO2) did not correlate well with mean ambulatory S(pO2) (r = 0.64) or the percent of monitored time spent with S(pO2) < 88% (r = 0.49). The lowest exercise S(pO2) also did not predict mean ambulatory S(pO2) (r = 0.39) or the percent of monitored time spent with S(pO2) < 88% (r = 0.32). Conventional evaluation overestimated LTOT requirements with 16 of the 20 patients developing an S(pO2) < 88%, most of them with exercise only (ie, most had normal resting S(pO2)). With ambulatory monitoring, however, only 3 of the 16 patients spent > 10% of the monitored time with S(pO2) < 88%. CONCLUSION: There was a poor relationship between the conventional oxygenation assessment method and continuous ambulatory oximetry during LTOT screening with COPD patients.

Activities of Daily Living↗
PubMed2003

Pleural fluid levels of vascular cell adhesion molecule-1 are elevated in eosinophilic pleural effusions.

STUDY OBJECTIVES: The mechanisms responsible for the accumulation of eosinophils in pleural fluid are not fully understood. The objective of the present study was to examine the relationship between pleural fluid eosinophilia and the levels of vascular cell adhesion molecule (VCAM)-1, eotaxin, RANTES (regulated upon activation, normal T-cell expressed and secreted), and interleukin (IL)-4 in pleural effusions. PATIENTS AND METHODS: Thirty-one patients with eosinophilic pleural effusion (EPE) [eosinophil percentage > 10% of the pleural fluid nucleated cells] and 10 patients without EPE were evaluated. VCAM-1, eotaxin, RANTES, and IL-4 in all pleural fluids were measured using enzyme-linked immunosorbent assay kits. IL-5 levels of the same fluids were measured in a previous study. RESULTS: VCAM-1, eotaxin, and RANTES but not IL-4 were detectable in the pleural fluids. The mean level of VCAM-1 in EPE (336 +/- 85 ng/mL) was significantly higher (p = 0.011) than that in the noneosinophilic effusions (260 +/- 34 ng/mL) [mean +/- SD]. VCAM-1 levels were significantly correlated with the eosinophil count and percentage in all pleural fluids (r = 0.43, p = 0.005, and r = 0.37, p = 0.019, respectively). Multiple linear regression analysis disclosed that both IL-5 (beta, 0.63; p < 0.001) and VCAM-1 (beta, 0.27, p = 0.025) are independent predictors of the number of eosinophils in all pleural fluids. RANTES and eotaxin did not differ significantly between EPEs and non-EPEs, and were not correlated with the number of pleural fluid eosinophils. CONCLUSION: The levels of VCAM-1 are increased in EPE, suggesting that VCAM-1 is important in the pathogenesis of EPE. Neither eotaxin nor RANTES is associated with pleural fluid eosinophilia.

Chemokine CCL11↗
PubMed2002

Prevalence and clinical course of pleural effusions at 30 days after coronary artery and cardiac surgery.

The present prospective study was designed to determine the prevalence of pleural effusion at approximately 28 days after cardiac surgery and their subsequent course. This consecutive case study included 389 patients; 312 had only coronary artery bypass graft surgery (CABG) surgery, 37 had both valve and CABG surgery, and 40 had only valve surgery. Chest radiographs were obtained approximately 28 days postoperatively. Patients were subsequently contacted by telephone 3, 6, and 12 months postoperatively and questioned about the presence of fluid in their chest and related symptoms. The prevalence of pleural effusions in the patients undergoing only CABG surgery (63%) or CABG surgery plus valve surgery (62%) was significantly (p = 0.05) higher than that in the patients undergoing valve surgery only (45%). The prevalence of effusions occupying more than 25% of the hemithorax was 9.7%. The primary symptom associated with these larger effusions was dyspnea. Chest pain and fever were uncommon. Over the 12-month follow-up, the effusions tended to resolve. In conclusion, the prevalence of pleural effusions occupying more than 25% of the hemithorax is approximately 10%, 28 days postoperatively. These larger pleural effusions produce dyspnea but not chest pain or fever, and most of the effusions disappear gradually over the subsequent months.

Coronary Artery Bypass↗
PubMed2002

Transforming growth factor beta induces vascular endothelial growth factor elaboration from pleural mesothelial cells in vivo and in vitro.

Vascular endothelial growth factor (VEGF) increases vascular permeability and is important in pleural effusion formation. In studies using transforming growth factor beta (TGF-beta) to produce pleurodesis, we observed that although TGF-beta was more effective than talc or doxycycline, it induced transient production of large pleural effusions. We hypothesized that TGF-beta stimulates VEGF production in pleural tissues in vivo, and by mesothelial cells in vitro. New Zealand White rabbits (n = 33) were given TGF-beta(2) (1.7 or 5.0 microg), talc (400 mg/kg), doxycycline (10 mg/kg), or buffer intrapleurally. Pleural fluid was collected at 24 h. Intrapleural injection of TGF-beta(2) induced a dose-dependent increase in VEGF production. The pleural fluid VEGF level was 2-fold higher in rabbits given 5.0 microg of TGF-beta(2) than in those given 1.7 microg of TGF-beta(2) and 3-fold higher than in those given buffer. VEGF levels were higher after the injection of TGF-beta(2) than after administration of talc or doxycycline. The pleural fluid VEGF correlated significantly with the volume of pleural effusions (r = 0.79, p < 0.00001). In vitro, TGF-beta(2) stimulated a dose-dependent increase in VEGF production from murine pleural mesothelial cells. At 4 and 24 h, TGF-beta(2), but not talc or doxycycline, induced a significant increase in VEGF, when compared with controls. The mesothelial cell VEGF production was significantly reduced by anti-TGF-beta antibody in the TGF-beta(2), talc, and control (buffer and medium) groups. In conclusion, mesothelial cells are an important source of VEGF. TGF-beta increases the VEGF production by mesothelial cells in vivo and in vitro.

Analysis of Variance↗
PubMed2002

Comparing transforming growth factor-beta2, talc and bleomycin as pleurodesing agents in sheep.

BACKGROUND: Transforming growth factor (TGF)-beta2 can produce effective pleurodesis in animals, but its efficacy has not been compared with commonly used pleurodesing agents in sheep, which have a thick pleura resembling that of humans. The acute physiological effects and the level of systemic TGF-beta absorption after its intrapleural administration have not been studied. The aims of the present study were to compare: (i) the effectiveness of TGF-beta2, talc and bleomycin in producing pleurodesis in sheep; (ii) the acute side-effects and systemic TGF-beta levels following the intrapleural administration of these agents; and (iii) histological changes after intrapleural injections of these agents. METHODOLOGY: Twelve sheep were divided into three groups and were given a single intrapleural dose of TGF-beta2 (0.25 microg/kg), talc slurry (5 g) or bleomycin (60 IU) via a chest tube. Saline or buffer was injected into the contralateral side, which served as the control. Arterial blood gases and respiratory and heart rates were monitored for the first 24 h. Plasma levels of TGF-beta1 and TGF-beta2 were measured. Pleurodesis was graded macroscopically from 1 (none) to 8 (symphysis > 50% of hemithorax) at day 14. RESULTS: At day 14, the pleurodesis score of the TGF-beta2 group (7.7+/-0.6) was similar to that of the talc (7.0+/-1.7) group and significantly higher than that of the bleomycin group (3.3+/-2.3; P < 0.05). No significant differences were seen in arterial blood gas analysis, vital signs and plasma TGF-beta1 and TGF-beta2 concentrations among the three groups. CONCLUSIONS: Transforming growth factor-beta2 was as effective as talc and more so than bleomycin in inducing pleurodesis in sheep. Intrapleural administration of TGF-beta2 appeared safe. No acute changes in gaseous exchange or macroscopic abnormalities were seen following intrapleural TGF-beta2. Importantly, there was no evidence of an increase in systemic TGF-beta levels following its intrapleural administration.

Analysis of Variance↗