Persistence of a multidrug-resistant Pseudomonas aeruginosa clone in an intensive care burn unit

Long-term colonization of various body sites with a multidrug-resistant Pseudomonas aeruginosa clone (resistant to piperacillin, cefoperazone, ceftazidime, aztreonam, imipenem, cefepime, cefpirome, ofloxacin, ciprofloxacin, minocycline, and aminoglycosides) with subsequent severe infections in burn patients has not been reported previously. Thirty-nine isolates of multidrug-resistant P. aeruginosa (resistant to ceftazidime and at least three of the agents listed above) recovered from various clinical samples from three patients in an intensive care burn unit from April 1997 to May 1997 and seven preserved isolates recovered from six patients in other medical wards at National Taiwan University Hospital from April 1996 to May 1997 were studied for their epidemiological relatedness. The epidemic could be attributed to a multidrug-resistant P. aeruginosa clone belonging to serogroup O:F (serogroup O:4) by means of antimicrobial susceptibility testing, O serogrouping, and analysis of the randomly amplified polymorphic DNA patterns generated by arbitrarily primed PCR of the isolates. The epidemic strain persisted in the three patients for weeks to months; in the meantime, these patients had received multiple antimicrobial agents for the management of intervening episodes of invasive infections (bacteremia, ventilator-associated pneumonia, and/or catheter-related sepsis) caused by this strain, as well as concomitant infections due to other organisms. The strain had been isolated only once previously, from a burn patient who was on the unit in December 1996. The present report, describing a small outbreak due to P. aeruginosa, documents the fact that a single clone of multidrug-resistant P. aeruginosa can cause long-term persistence in different body sites of burn patients and that the colonization can subsequently result in various severe infections.

Heparinization on pericardial substitutes can reduce adhesion and epicardial inflammation in the dog

OBJECTIVE

Primary concerns about currently available pericardial substitutes include adhesion and epicardial reaction. The purpose of this study is to evaluate host reaction to pericardial substitutes with and without incorporating slow heparin release.

METHODS

To avoid biologic variation among these pericardial patches, we made a composite of six membranes. The composite membrane consisted of epoxy-fixed patches with (1) or without (2) ionically bound heparin, a glutaraldehyde-fixed patch with (3) or without (4) ionically bound heparin, an expanded polytetrafluoroethylene patch (5), and a polyester polymeric patch (6). Ten recipient dogs weighing from 12 to 19 kg (mean 13.6 kg) were used to assess the composite membranes as pericardial substitutes. The implanted composite membranes were retrieved 1 week (one dog), 2 weeks (one dog), 4 weeks (one dog), 8 weeks (one dog), and 12 weeks (six dogs) after implantation.

RESULTS

Overall, the synthetic patches had a more notable inflammatory reaction than the biologic patches with or without ionically bound heparin. The heparin-bound patches caused significantly less inflammation than their nonheparinized counterparts. The heparinized porcine patches cross-linked with different compounds were found to have less fibrous formation than the nonheparinized patches and the synthetic patches.

CONCLUSIONS

Heparinized pericardial substitutes may cause less adhesion and inflammatory reaction than nonheparinized material.

Quantitative analysis of mRNA encoding MUC1, MUC2, and MUC5AC genes: a correlation between specific mucin gene expression and sialomucin expression in non-small cell lung cancer

The expression of mucins is important for tumor invasiveness and metastasis. In our previous report (Am. J. Respir. Crit. Care Med. 1997; 155:1419-1427), non-small cell lung cancers bearing sialomucin expression tended to relapse earlier than those without sialomucin. However, it remained unclear whether the expression of sialomucin in lung cancer is caused by an abnormal glycosylation process or by the expression of a specific mucin gene product. To address this problem, we established a modified quantitative competitive polymerase chain reaction (QC-PCR) analysis. RNA internal standards of MUC1, MUC2, and MUC5AC non-tandem repeat sequences were constructed, and known copy numbers of mucin RNA internal standards were introduced into reverse transcription-polymerase chain reactions (RT-PCR) for each mucin gene in order to compete with native mucin gene RNA during the reaction. The RNA of Gbeta-like gene (a housekeeping gene) was used as internal control for the RNA analysis. Twenty-five lung cancer tissues (13 adenocarcinomas and 12 squamous cell carcinomas) were used for analysis. Mann-Whitney rank sum test was applied to compare the expression amounts of different mucin genes in tissues. The results revealed that adenocarcinoma expressed higher amounts of MUC5AC gene than did squamous cell carcinoma (P = 0.03). The expression amount of MUC5AC correlated positively with the expression status of sialomucin (P = 0.012). Further studies are anticipated to elucidate the underlying mechanism contributing to this phenomenon.

PKC activation is required by EGF-stimulated Na(+)-H+ exchanger in human pleural mesothelial cells

Epidermal growth factor (EGF) stimulates the Na(+)-H+ exchanger, leading to enhanced cell proliferation. In human pleural mesothelial cells (PMCs), the intracellular signaling mechanism mediating the EGF-induced stimulation of the Na(+)-H+ exchanger has not yet been identified. Using a pH-sensitive fluorescent probe, 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, to measure changes in intracellular pH (pHi), we found that 1) EGF and 12-O-tetradecanoylphorbol 13-acetate (TPA; a phorbol ester) both stimulate the ethylisopropyl amiloride-sensitive Na(+)-H+ exchanger; 2) TPA-induced alkalosis can be blocked by protein kinase C (PKC) inhibitors (chelerythrine and staurosporine) or by PKC down-regulation, indicating that PKC activation is involved in the stimulation of the Na(+)-H+ exchanger. However, TPA-induced alkalosis is not blocked by tyrosine kinase inhibitors; and 3) the stimulatory effect of EGF on the Na(+)-H+ exchanger acts via stimulation of tyrosine kinase-receptor activity because it is inhibited by tyrosine kinase inhibitors (genistein, lavendustin A, and herbimycin A). It also involves PKC activation because EGF-induced alkalosis was blocked by PKC inhibitors. These results suggest that PKC activation is one of the downstream signals for EGF-induced activation of the Na(+)-H+ exchanger in primary cultures of human pleural mesothelial cells.

Recurrent catheter-related infection caused by a single clone of Mycobacterium chelonae with two colonial morphotypes

We describe herein a recurrent catheter-related (Port-A-Cath; Smiths Industries Medical Systems [SIMS] Deltec, Inc., St. Paul, Minn.) infection caused by multidrug-resistant Mycobacterium chelonae with two colonial morphotypes in a 53-year-old woman with gastric adenocarcinoma. Four isolates recovered from this patient within a 3-month period were found to belong to a single clone on the basis of the isolates' identical antibiotypes as determined by the E test and their identical random amplified polymorphic DNA patterns.

Indwelling device-related and recurrent infections due to Aeromonas species

From October 1995 to February 1997, 13 isolates of Aeromonas species were recovered from four patients treated at National Taiwan University Hospital (Taipei). One of the patients, a diabetic, had simultaneous Aeromonas veronii biotype veronii bacteremia and A. veronii biotype sobria urinary tract infection. Seven weeks after the episode, the patient had necrotizing fasciitis due to A. veronii biotype veronii. The other three patients all had underlying hepatobiliary malignancies complicated by obstructive jaundice, and all underwent percutaneous transhepatic cholangiographic drainage. These three patients had multiple isolates of Aeromonas species (A. hydrophila and/or A. caviae) recovered from samples of blood or bile or from catheter insertion sites. All isolates were identified on the basis of the results of extended biochemical tests as well as characteristic cellular fatty acid profiles. The results of genotyping generated by arbitrarily primed polymerase chain reaction and of susceptibility testing showed that these Aeromonas species were pathogens that caused indwelling device-related infections and that the organisms could persist for long periods, with subsequent recurrence of severe infection. Concomitant infection due to more than one Aeromonas species or caused by polyclonal A. hydrophila or A. veronii biotype veronii was also documented.

Nosocomial infections caused by Sphingomonas paucimobilis: clinical features and microbiological characteristics

From January 1995 to September 1996, 14 isolates of Sphingomonas paucimobilis, including 11 from clinical specimens from six patients with nosocomial infection and three from environmental sources, were collected. Two of the six patients had intravascular catheter-related bacteremia and one each had bacteremic biliary tract infection, urinary tract infection, ventilator-associated pneumonia, and wound infection. The S. paucimobilis isolates were identified according to biochemical profiles established with use of the API 20NE system and Vitek GNI card and the characteristic cellular fatty acid chromatogram. Ten biotypes, 11 antibiograms (by the Etest), and 12 random amplified polymorphic DNA (RAPD) patterns (by arbitrarily primed polymerase chain reaction) were identified. The identical biotype, antibiogram, and RAPD pattern of the two isolates (one each from blood and bile) from a patient with biliary tract infection indicated the invasiveness of the organism. Two patients with intravascular catheter-related bacteremia had isolates of this organism repeatedly recovered, and these isolates had heterogeneous RAPD patterns. The present study highlights the wide distribution in hospital environments of various clones of S. paucimobilis, which may cause recurrent infections by a single strain or several episodes of infection due to two or more clones of this organism in hospitalized patients.

Diagnosis of pulmonary sequestration by magnetic resonance imaging

Pulmonary sequestration, an uncommon congenital anomaly, is traditionally best diagnosed using arteriography; however, this is invasive and not without risk of morbidity and mortality. We report two patients with pulmonary sequestration diagnosed using magnetic imaging techniques. The first was a 22-year-old woman and the second a 17-year-old boy, both of whom presented with symptoms of cough and exertional dyspnea. Pulmonary sequestration was suspected from their chest radiographs. Magnetic resonance imaging and magnetic resonance angiography clearly demonstrated the aberrant artery arising from the aorta in a single noninvasive examination that did not require the use of contrast medium. We recommend magnetic resonance imaging as a safe, efficient, and noninvasive modality for the diagnosis of pulmonary sequestration.

Evaluation of an automatic polymerase chain reaction assay for identification of Mycobacterium tuberculosis in respiratory specimens

We evaluated the performance of an automatic polymerase chain reaction (PCR) detection system for identification of Mycobacterium tuberculosis in respiratory specimens. Six hundred and two respiratory specimens, including 557 sputa and 45 bronchial washing samples, were analyzed using the COBAS AMPLICOR Mycobacterium tuberculosis (MTB) test. The results were compared with those obtained from acid-fast microscopy, conventional culture, and clinical history. In cases of discrepancy between the results of the COBAS AMPLICOR MTB test and culture, the medical history of the patient was reviewed, the COBAS AMPLICOR MTB test was repeated, and the gene encoding M. tuberculosis superoxide dismutase was screened using PCR (SOD-PCR). Fourteen samples were excluded because the internal control test result was negative. Of 57 specimens that were culture positive for Mycobacterium species, 40 appeared to have growth of M. tuberculosis and 21 were smear positive for acid-fast bacteria. The sensitivity, specificity, and positive and negative predictive values for the COBAS AMPLICOR MTB test evaluated at our laboratory were 85.0% (34/40), 99.3% (544/548), 89.5% (34/38), and 98.9% (544/550), respectively. Three specimens that were culture positive for M. tuberculosis but negative by COBAS AMPLICOR MTB test were positive when rechecked by both COBAS AMPLICOR MTB test and SOD-PCR. Among the four specimens with positive reactions on both COBAS AMPLICOR MTB test and SOD-PCR that were culture negative, two were from patients who had been receiving antituberculosis treatment, one was from a patient who had been treated for tuberculosis for 1 year, and the other was from a patient who died of sepsis with adult respiratory distress syndrome. In more than 70% of smear-negative and culture-positive specimens and 86.4% of smear-positive specimens, M. tuberculosis was identified by the COBAS AMPLICOR MTB test within 10 hours after receipt of the specimens. Our data show that the COBAS AMPLICOR MTB test provides rapid and accurate detection of M. tuberculosis in respiratory specimens.

Pulmonary arteriovenous malformation: analysis of 10 cases

Pulmonary arteriovenous malformation (PAVM) is an uncommon but not rare disease. It is very often associated with hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu disease, OWRD). Both conditions may be readily diagnosed at the bedside when careful attention is given to clues from history taking and physical examination. Sometimes the clinical features may be neglected, delaying the diagnosis. The natural history of this disease is still incompletely understood because of the paucity of cases. This retrospective study was undertaken to evaluate the clinical manifestations and treatment options in patients with documented PAVM at the National Taiwan University Hospital between 1985 and 1997. Ten patients (4 men, 6 women) of documented PAVM were evaluated. Mean age at diagnosis was 37.8 years (range 22-63). Presenting symptoms included dyspnea on exertion, characteristics of OWRD, and major neurologic events. Six episodes of brain abscess occurred in three patients. The predominant location of PAVMs was the lower lobe. Solitary PAVM was more frequent in our patients (5/6) with OWRD than in other reports. The therapeutic options were: surgical resection (3 patients), embolotherapy (4), and no treatment (4). One patient, who refused treatment at first, developed a brain abscess later. There was no documented recurrence or growth of new PAVMs in patients who underwent surgical resection. Embolotherapy failed in one patient; no recanalization was found in the remaining patients. In conclusion, the diagnosis of PAVM may be subtle, but careful attention to historic clues and physical findings may lead to early diagnosis. Appropriate treatment is mandatory and may prevent the severe complications of PAVM. The debate about the preferred treatment seems likely to continue until more is known about the natural history of this disease.

Magnetic resonance angiography in the diagnosis of thoracic venous obstruction

The aims of this study were to evaluate the diagnostic value of orthogonal magnetic resonance angiography (MRA) and to compare the results of MRA with those of digital subtraction venography (DSV) in thoracic venous diseases. Ten normal volunteers were evaluated using two-dimensional time-of-flight MRA in three orthogonal planes to determine the image quality of each venous segment. Twelve consecutive patients suspected of having thoracic venous disease were studied with both MRA and DSV. In the normal subjects, the plane perpendicular to the target vein provided the most consistent visualization. Using three orthogonal MRA images, a diagnostic-quality image was obtained in 175 (83%) of 210 venous segments in normal volunteers. In patients with thoracic venous obstructive disease, MRA was more effective than DSV in detecting total (84 vs 54), patent (56 vs 36), stenotic (13 vs 10), and obstructive (15 vs 8) venous segments, poststenotic or postobstructive veins (15 vs 10), thrombosis of the internal jugular vein (7 vs 2), intraluminal thrombus (5 vs 3), and azygos veins (12 vs 2). Using venous segments visible on DVS (n = 54) as the standard, the sensitivity and specificity of MRA were 94% and 100%, respectively, in detecting venous patency, and 100% and 98% in detecting complete venous obstruction. In the shoulder region, the sensitivity and specificity of MRA were 93% and 100%, respectively, in detecting venous patency, and 100% and 97% in detecting venous obstruction. We conclude that MRA with three orthogonal planes can provide relatively complete and reliable venous mapping, without the need for contrast medium.

Susceptibilities of Chryseobacterium indologenes and Chryseobacterium meningosepticum to cefepime and cefpirome

In vitro activities of cefepime and cefpirome against 96 isolates of Chryseobacterium indologenes and 21 of C. meningosepticum were determined by the agar dilution method. Overall, cefepime was more active than cefpirome against C. indologenes (MIC at which 50% of the isolates were inhibited [MIC50] and MIC90, 4 and 16 microg/ml, respectively, for cefepime and 8 and 128 microg/ml, respectively, for cefpirome). Both agents had poor potency against C. meningosepticum (MIC50 and MIC90, 64 and >256 microg/ml, respectively, for cefepime and 128 and >256 microg/ml, respectively, for cefpirome).

Alteration of endogenous antioxidant enzymes in naturally occurring hypertrophic cardiomyopathy

We have recently developed a porcine model with naturally occurring hypertrophic cardiomyopathy (HCM). Similar to humans, occluded intramural coronary artery and damaged mitochondria are frequently observed in these animals in which the disease is thought to be associated with the local ischemia of myocardium. In view of antioxidant functions involved in the ischemic injury, we measured the expression of endogenous antioxidant enzymes in the tissues with and without HCM. The results showed a significant increase of Cu,Zn-superoxide dismutase (SOD), but not Mn-SOD, and decrease of catalase (CAT) activities in the various areas of HCM hearts. It was demonstrated that SOD/CAT ratios in the HCM hearts were significantly higher than those in normals and were found to be dramatically correlated with the severity of cardiac hypertrophy. The altered SOD/CAT ratio was also consistent with increase in lipid damage. We hypothesize that the elevated SOD combined with an inadequate amount of H2O2 scavenging enzyme may lead HCM heart at oxidative stress risk. However, the pathogenic role of imbalanced antioxidant enzyme needs to be further explored.

Sonographic imaging of the trachea

We evaluated the feasibility of ultrasonography for imaging of the trachea and its effectiveness in the diagnosis and follow-up of patients with tracheal stenosis due to various diseases. Twenty normal volunteers and six adult patients with tracheal stenosis were included in the study group. Subjects were examined with ultrasonography in a supine position with the neck hyperextended or in a sitting position. At the level of the thyroid isthmus, the anterior tracheal wall thicknesses imaged by ultrasonography were 1.54 +/- 0.22 mm (mean +/- SD) and 1.22 +/- 0.18 mm for normal male and female volunteers, respectively. Ultrasonography could reveal the intrinsic tracheal wall lesions and extrinsic lesions compressing the trachea in patients with tracheal stenosis. These ultrasonographic images correlated with CT images. In conclusion, ultrasonography may be useful in imaging of the trachea.

Empyema thoracis and lung abscess caused by viridans streptococci

We retrospectively studied the bacteriology and clinical features of empyema thoracis and lung abscess caused by viridans streptococci in 72 patients seen from January 1984 to September 1996. A total of 76 strains of viridans streptococci were isolated, of which the most common isolates were Streptococcus constellatus (21 strains), S. intermedius (17), and S. sanguis (10). Species belonging to the S. milleri group accounted for the majority (68%) of isolates. In 38 (53%) patients these organisms were recognized as the sole pathogens. Of the 72 patients, 53 had empyema, 14 had lung abscesses, and five had both empyema and lung abscess. Forty-six (64%) patients had underlying diseases. Of these, malignancies were the most common (17 patients), followed by diabetes mellitus (12 patients) and central nervous system diseases (10 patients). Of the 48 patients who underwent chest-tube drainage, 27 (56%) received further treatments, including intrapleural streptokinase (18 cases), surgery (9), and both intrapleural streptokinase and surgery (3). Two (14%) of the patients with lung abscess alone underwent surgical treatment. Although all viridans streptococcal isolates were susceptible to penicillin, the patients in the study had a high mortality (21%). Univariate and multivariate analysis of data for patients with empyema alone (n = 53) showed a significantly increased risk of death in those with underlying malignancy (OR = 16.0, p = 0.023) and those with non-S. milleri-group isolates (OR = 3.72, p = 0.030). These data imply a strong clinical significance of viridans streptococci in the pathogenesis of empyema and lung abscess, as well as the need for species identification of viridans streptococci in patients with pleuropulmonary diseases.

Elevated serum levels of mucin-associated antigen in patients with acute respiratory distress syndrome

Increased serum levels of mucin-associated antigen have been previously demonstrated in patients with cystic fibrosis (CF) and interstitial pneumonia, and in lung-transplant recipients. The present study assessed the serum airway mucin levels in patients with acute respiratory distress syndrome (ARDS). An enzyme-linked immunosorbent assay (ELISA) method with a human-airway-mucin-specific monoclonal antibody (17Q2) was used to measure serum mucin levels in normal subjects, chronic smokers, patients with chronic bronchitis and other pulmonary diseases, patients with acute cardiogenic lung edema, and patients with ARDS. The serum mucin levels measured 9.9 +/- 0.8 ng/ml (mean +/- SEM, n = 59) in normal subjects, 12.7 +/- 1.6 ng/ml (n = 29) in chronic smokers, 21.8 +/- 1.9 ng/ml (n = 28) in patients with chronic bronchitis and other pulmonary diseases, 9.0 +/- 3.1 ng/ml (n = 5) in patients with acute cardiogenic lung edema. The serum mucin level was 53.8 +/- 6.6 ng/ml (n = 13) in patients with ARDS (p < 0.05, as compared with the four other groups). Serial measurements of serum mucin levels were obtained in patients with ARDS. Statistical analysis showed an inverse correlation of serial measurements of serum mucin with static respiratory-system compliance (p = 0.021), an inverse correlation of sequential serum mucin levels and log(Pa(O2)/Fl(O2)) (p = 0.016), and a positive correlation of sequential serum mucin levels and lung injury score (LIS) (p = 0.019). Gel-filtration analysis showed that mucin-associated antigens in ARDS sera were polydispersed and smaller than the antigens in normal sera. This study indicates that an increasing amount of degraded mucin occurs in patients with ARDS.

Osteomyelitis and tenosynovitis due to Mycobacterium marinum in a fish dealer

Osteomyelitis caused by nontuberculous mycobacteria is rarely reported. We describe a case of tenosynovitis and osteomyelitis of the right middle finger and metacarpal bone caused by Mycobacterium marinum in a fish dealer. This 52-year-old woman suffered progressive pain, numbness, tenderness, and erythematous swelling of the right middle finger over a 2-month period. A radiograph of the right hand disclosed osteolytic lesions at the third metacarpal bone and the third proximal phalanx. She was treated successfully with repeated surgical debridement and antimicrobial agents, including clarithromycin, ethambutol, rifampin, and doxycycline for 1 month, followed by ethambutol and clarithromycin. Pathologic examination of the debrided tissue disclosed epithelioid granuloma, caseous necrosis, and numerous acid-fast bacilli, which were later identified as M. marinum using conventional biochemical tests and by the characteristic gas-liquid chromatogram of esterified cellular fatty acid. The wound healed completely after 7 months of treatment. The patient is still under treatment, and clarithromycin and ethambutol will be given for a total of 18 months.

Persistence of porcine reproductive and respiratory syndrome virus in intensive farrow-to-finish pig herds

An epidemiological study of porcine reproductive and respiratory syndrome (PRRS) within pig herds was conducted in 8 intensive farrow-to-finish pig farms. Persistence of PRRS virus (PRRSV) in pig herds was demonstrated by regular postmortem examination on 2 farms for a period of 2 y. Virus isolation and serum neutralization (SN) tests were performed on the sera collected from 9 groups of pigs (10 pigs/group) of various ages on 8 pig farms. Except for 1 farm, isolation rates of PRRSV reached the highest level of 70 to 100% of pigs 6 to 8 wk of age, which coincided with the lowest levels of maternal immunity. In 1 pig herd, sows (39 in total) with SN titers of < or = 1:2, 1:4-1:8, and > or = 1:16 were designated as groups 1, 2, and 3, respectively. Sera were obtained from their progeny (3 pigs randomly selected from each litter) at various ages from 0 to 22 weeks. A positive correlation (r = 0.377, P < 0.001) between the SN titers of sows and those of their progeny (1-week-old piglets) was observed. Pigs at the age of 6 wk, only 7.9% of group 1 pigs compared to 72.4% of group 3 pigs were seropositive. A significant difference (P < 0.01) in the percentage of pigs with PRRSV viremia among the 3 groups was observed, with the lowest level found in group 3 pigs. The isolation rates of PRRSV from serum reached the maximum at the age of 9 wk for all 3 groups. The results indicated that passively acquired serum antibodies conferred a protective effect for piglets; however, loss of passive immunity at various ages of pigs produced susceptible pigs that resulted in PRRSV persistence in the pig herds. Pigs 6 to 9 weeks old were the major reservoir for PRRSV in farrow-to-finish pig herds.

Intramural coronary artery disease in swine with naturally occurring hypertrophic cardiomyopathy

Intramural coronary artery disease (ICAD) has been reported in myocardium affected with hypertrophic cardiomyopathy (HCM), but has never been studied in detail with respect to the cell type or lipid infiltration involved in the wall-thickening. The lack of heart samples may be one of the rationales to hamper the progress in investigating this disease. Recently, the discovery of naturally occurring HCM in swine has provided an excellent opportunity for the study of ICAD because of the high prevalence of ICAD in this animal. The present study provides a detailed structure feature in the thickened arterial wall of ICAD by both histologic and electron microscopic means. Morphologically, the feature of ICAD is due primarily to the neointimal thickening. Smooth muscle cells (SMC) and extracellular matrix (collagen and elastic fibers) are the major components responsible for the thickened neointima. Fragmentation of the internal elastic membrane is associated with the migration and proliferation of SMC from the media to the intima. Therefore, pigs with HCM may be a potential animal model not only for the study of the mechanism by which SMC migrate and proliferate into intima, but also for the future investigation of interventions in coronary artery occlusion.

Ultrasound-guided transthoracic biopsy of peripheral lung, pleural, and chest-wall lesions

Ultrasound (US)-guided transthoracic biopsy is well suited for the sampling of those mediastinal, hilar, pleural, chest-wall, and peripheral lung lesions that provide an adequate acoustic window to the transducer. Chest-wall, pleural, and peripheral lung lesions are generally hypoechoic relative to their surrounding tissues. A special puncture transducer is used to perform US-guided biopsy with real-time visualization of the biopsy needle and the lesion. For vascular lesions and lesions adjacent to mediastinal vessels, a color Doppler puncture device is now available. The accuracy of US-guided biopsy of peripheral lung lesions or chest-wall lesions is 88% to 100%, with particular utility in the diagnosis of pulmonary masses with large necrotic centers. Other lung lesions amenable to US-guided biopsy diagnosis include those producing superior vena cava (SVC) syndrome, Pancoast's syndrome, or obstructive pneumonitis. Pulmonary consolidation, lung abscess, and parapneumonic effusions are easily sampled for microbiologic diagnosis. The peripheral nature of lesions accessed by US guidance accounts for a very low rate of complications. Although US-guided needle biopsy requires certain expertise, the technique is relatively easy to master and can be performed in many situations where computed tomography-guided biopsy would previously have been used.

Selection of invasive and metastatic subpopulations from a human lung adenocarcinoma cell line

To better understand the mechanism(s) underlying lung cancer invasion and metastasis, a Transwell invasion chamber was used to select progressively more invasive cancer cell populations from a clonal cell line of human lung adenocarcinoma, CL1. Five sublines with progressive invasiveness, designated CL1-1, CL1-2, CL1-3, CL1-4, and CL1-5, were obtained through this in vitro selection process. Their invasive abilities through basement membrane matrix showed a 4- to 6-fold increase over that of the parental cells. Moreover, the sublines manifested an increase in their colony-forming ability on soft agar, tumorigenicity, and metastatic potency in severe combined immunodeficiency (SCID) mice. Examining the phenotypes of the cell lines revealed increased expression of 92 kD gelatinase and an increase in the cell population stained with anti-keratin-8 and -18 antibodies. Clonal isolation of anti-keratin-18-antibody-positive and -negative cell populations demonstrated a correlated enhancement of the invasiveness of these cells and their expression of keratin-18. These results support the notion that the metastatic behavior of lung cancer cells can be characterized with this in vitro system, and that the properties of these progressively invasive cancer cells can be clonally studied.

Comparison of inflammatory cytokine concentration and physiologic parameters in septic shock

Cytokine-related systemic intravascular inflammation may represent a common pathogenic link between initial insult and multiple organ failure in septic shock patients. We conducted a prospective study with controls in the National Taiwan University Hospital intensive care unit to compare plasma levels of tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), and circulating intercellular adhesion molecule 1 (cICAM-1) with clinical physiologic parameters in the outcome of patients with septic shock. Healthy volunteers (n = 37) and patients with septic shock admitted to the unit from January to December 1994 (n = 31) were enrolled. Clinical data, APACHE (Acute Physiology and Chronic Health Evaluation) III scores, multiple organ failure scores, the presence of acute respiratory distress syndrome, and outcome were evaluated. The plasma levels of TNF-alpha, IL-6, and cICAM-1 were measured using enzyme-linked immunosorbent assay. Subgroups of survivors and nonsurvivors were compared for plasma levels of these factors or days 1, 2, 3, 7, and 14 after diagnosis of septic shock. Of the patients with septic shock, 20 survived and 11 died. The initial plasma levels of IL-6 were significantly higher in nonsurvivors (p < 0.05). There was a significant inverse correlation between plasma IL-6 level and survival in the first week (r = 0.4297-0.7242, p < 0.05). APACHE III score (r = 0.4335, p = 0.015), acute respiratory distress syndrome (r = 0.5913, p < 0.001), and multiple organ failure score (r = 0.736, p < 0.001) were more strongly (negatively) correlated with survival than the concentrations of TNF-alpha and cICAM-1 by Spearman's rank sum test. Our results showed that in patients with septic shock, of the inflammatory cytokines, only IL-6 showed significantly higher plasma levels in the nonsurvivor group. Inflammatory cytokine levels were not more strongly correlated with the outcome of patients with septic shock than physiologic parameters.

Rapid transepithelial antigen transport in rat jejunum: impact of sensitization and the hypersensitivity reaction

BACKGROUND & AIMS

Intestine from sensitized rats develops a rapid secretory response to luminal antigen challenge that depends on activation of subepithelial mast cells. The aim of this study was to determine the timing and route of the transepithelial protein antigen transport.

METHODS

Rats were sensitized to horseradish peroxidase (HRP). After 10-14 days, jejunal segments were resected, mounted in Ussing chambers, and challenged with HRP on the luminal side.

RESULTS

Electron microscopy of tissue specimens fixed at 2 minutes (before mast cell activation) showed enhanced endocytic uptake of HRP in enterocytes of HRP-sensitized rats compared with ovalbumin-sensitized or saline-injected controls. At this time, HRP was distributed throughout epithelial cells and was already evident in the lamina propria. In contrast, HRP was restricted to the apical region of enterocytes in controls. At 30 minutes (after mast cell activation), in HRP-sensitized rats only, HRP was also located within tight junctions and the paracellular region between epithelial cells. Tissue conductance was increased in HRP-sensitized rats beginning 30 minutes after HRP addition and correlated with the overall flux of HRP across the tissue.

CONCLUSIONS

The results show that specific sensitization enhances the initial uptake and transcytosis of antigen across intestinal epithelium. Subsequent to activation of mast cells, antigen transport is further enhanced by penetration through the paracellular pathway.

Serodiagnosis of tuberculosis. A study comparing three specific mycobacterial antigens

To compare the efficacy of different mycobacterial specific antigens and to assess the applicability of the combination of several different antigens in the diagnosis of tuberculosis, three ELISA tests derived by Antigen 60, 38kda, and Kp90 were evaluated in 594 Chinese patients (312 patients with active pulmonary tuberculosis and 282 control subjects). Quantified levels of sensitivity and specificity were compared with those in the nontuberculous control groups. Antigen 60 IgG (sensitivity and specificity, 80.77 and 88.4%) was more antigenic and more effective in its determination than was 38kda IgG (sensitivity and specificity, 64.21 and 80.74%) and Kp90 IgA (sensitivity and specificity, 62.58 and 66.3%). The clinical significance of the difference, however, was not striking: negative predictive value of Antigen 60, 38kda, and Kp90 was 93, 86 and 83%, respectively; positive predictive value of Antigen 60, 38kda, and Kp90 was 71, 54, and 39%, respectively. Combination of different antigens could improve the sensitivity and specificity by no more than 10%, with the sacrifice of the opposite parameter by no less than 20%. The same improvement in sensitivity could be easily achieved by adjusting the cutoff values in the ELISA test by a single antigen. We conclude that the sensitivity and specificity of presently available antigens for serodiagnosis of tuberculosis still remains limited at around 80%, which makes it a poor diagnostic tool for disease confirmation. In low incidence areas, its clinical value may be useful in disease exclusion. A combination of several different antigens provides no more improved diagnostic yield than what can be provided by cutoff value adjustment in a single antigen serologic test.