Comparison of polymerase chain reaction with adenosine deaminase activity in pericardial fluid for the diagnosis of tuberculous pericarditis

Diagnostic accuracy of tests for tuberculous pericarditis: A network meta-analysis

Tuberculous pericarditis (TBP) is a relatively uncommon but potentially fatal extrapulmonary manifestation of tuberculosis. Despite its severity, there is no universally accepted gold standard diagnostic test for TBP currently. The objective of this study is to compare the diagnostic accuracy of the most commonly used tests in terms of specificity, sensitivity, negative predictive value (NPV), and positive predictive value (PPV), and provide a summary of their diagnostic accuracies. A comprehensive literature review was performed using Scopus, MEDLINE, and Cochrane central register of controlled trials, encompassing studies published from start to April 2022. Studies that compared Interferon Gamma Release Assay (IGRA), Xpert MTB/RIF, Adenosine Deaminase levels (ADA), and Smear Microscopy (SM) were included in the analysis. Bayesian random-effects model was used for statistical analysis and mean and standard deviation (SD) with 95% confidence intervals were calculated using the absolute risk (AR) and odds ratio (OR). Rank probability and heterogeneity were determined using risk difference and Cochran Q test, respectively. Sensitivity and specificity were evaluated using true negative, true positive, false positive, and false negative rates. Area under the receiver operating characteristic (AUROC) was calculated for mean and standard error. A total of seven studies comprising 16 arms and 618 patients were included in the analysis. IGRA exhibited the highest mean (SD) sensitivity of 0.934 (0.049), with a high rank probability of 87.5% for being the best diagnostic test, and the AUROC was found to be 94.8 (0.36). On the other hand, SM demonstrated the highest mean (SD) specificity of 0.999 (0.011), with a rank probability of 99.5%, but a leave-one-out analysis excluding SM studies revealed that Xpert MTB/RIF ranked highest for specificity, with a mean (SD) of 0.962 (0.064). The diagnostic tests compared in our study exhibited similar high NPV, while ADA was found to have the lowest PPV among the evaluated methods. Further research, including comparative studies, should be conducted using a standardized cutoff value for both ADA levels and IGRA to mitigate the risk of threshold effect and minimize bias and heterogeneity in data analysis.

Detection of drug-resistant Mycobacterium tuberculosis in pericardial fluid culture and its correlation with cartridge based nucleic acid amplification test and adenosine deaminase activity

BACKGROUND

Pericardial effusion is the accumulation of fluid in the pericardial cavity. In nations with high tuberculosis (TB) load, TB is the most common cause of pericardial effusion. 1-2% of patients with pulmonary TB develop Pericardial TB worldwide. Multi-drug-resistant (MDR) TB, including extrapulmonary TB (EPTB) cases, are rising in number. Adenosine Deaminase (ADA) is an enzyme in lymphocytes and myeloid cells, which has certain immune functions in the body. ADA levels are increased in inflammatory conditions, like pleural, pericardial, or joint effusions, of bacterial etiology, granulomatous conditions, neoplasms, and autoimmune pathologies. TB is the only lymphocytosis involving disease with increased ADA levels. MDR EPTB is rare, but cases are on the rise, and tuberculous pericardial effusion is one such example. Hence, it is important to know the percentage of cases detected by a culture that can be identified by cartridge-based nucleic acid amplification test (CBNAAT), their resistance patterns, and to identify potential markers like ADA, which can help in early identification of cases. The objectives of this study were to identify the Mycobacterium tuberculosis (MTB) bacilli in culture, and correlate them with cartridge-based nucleic acid amplification test (CBNAAT) results and their drug-resistance, in the Pericardial tubercular effusion, and to find if Adenosine Deaminase (ADA) levels can be used as a predictor of the presence of MTB in pericardial fluid.

METHODOLOGY

We enrolled 52 patients with moderate to large tuberculous pericardial effusion, based on pericardial fluid analysis, CBNAAT, and culture methods, between January 2021 and December 2021.

RESULTS

The mean age of the patients was 41.85 + 17.88 years, with a median of 38 years. Males made up 57.7% of the total patients. MTB was detected in 16 (30.8%) patients in the CBNAAT evaluations. 14 (87.5%) of the CBNAAT-positive TB patients were sensitive to Rifampicin, whereas the remaining 2 (12.5%) were resistant to Rifampicin on CBNAAT. MTB was found to be growing in 8 (15.38%) drug sensitivity test cultures. Out of these 8, 6 were sensitive to first-line drugs, whereas 2 were resistant to both Isoniazid and Rifampicin. The presence of cough was found to have a significant difference between CBNAAT-detected MTB positive and negative patients (p = 0.020), whereas an insignificant difference was found for the presence of hypertension, diabetes mellitus, obesity, dyspnea, or fever. There was also an insignificant difference between the number of patients positive for the Tuberculin skin test, between the two groups. ADA was significantly higher in the MTB-detected CBNAAT group (85.91 + 37.60U/L vs 39.78 + 24.31U/L, p = 0.005), whereas the total leukocyte count, lymphocytes, neutrophils, random blood sugar levels, and serum protein levels had no significant difference. The area under the Receiver Operator Curve (CBNAAT positive: dependent variable; ADA: test result variable) was 0.854 (null hypothesis rejected), with a standard error of 0.078.

CONCLUSIONS

Culture is the gold standard method to diagnose tuberculosis. Detection of MTB on pericardial fluid culture is very uncommon, though in our study, culture came out positive in 16% of patients, and 4% were resistant to rifampicin and isoniazid. Higher ADA levels in pericardial fluid are an indicator of tuberculous pericardial effusion.

Tuberculous Pericarditis—Own Experiences and Recent Recommendations

Tuberculous pericarditis (TBP) accounts for 1% of all forms of tuberculosis and for 1–2% of extrapulmonary tuberculosis. In endemic regions, TBP accounts for 50–90% of effusive pericarditis; in non-endemic, it only accounts for 4%. In the absence of prompt and effective treatment, TBP can lead to very serious sequelae, such as cardiac tamponade, constrictive pericarditis, and death. Early diagnosis of TBP is a cornerstone of effective treatment. The present article summarises the authors’ own experiences and highlights the current status of knowledge concerning the diagnostic and therapeutic algorithm of TBP. Special attention is drawn to new, emerging molecular methods used for confirmation of M. tuberculosis infection as a cause of pericarditis.

An overview of human pericardial space and pericardial fluid

The pericardium is a double-layered fibro-serous sac that envelops the majority of the surface of the heart as well as the great vessels. Pericardial fluid is also contained within the pericardial space. Together, the pericardium and pericardial fluid contribute to a homeostatic environment that facilitates normal cardiac function. Different diseases and procedural interventions may disrupt this homeostatic space causing an imbalance in the composition of immune mediators or by mechanical stress. Inflammatory cells, cytokines, and chemokines are present in the pericardial space. How these specific mediators contribute to different diseases is the subject of debate and research. With the advent of highly specialized assays that can identify and quantify various mediators we can potentially establish specific and sensitive biomarkers that can be used to differentiate pathologies, and aid clinicians in improving clinical outcomes for patients.

Chronic massive pericardial effusion: a case report and literature review

Chronic massive pericardial effusion without cardiac tamponade is relatively rare. Nearly half of all patients with chronic large pericardial effusion are asymptomatic. We report a case of a 77-year-old man who presented with an asymptomatic chronic massive pericardial effusion, with no evidence of cardiac tamponade or pericardial constriction during a 10-year follow-up. The patient had a complex history of lymph node tuberculosis, hypertension, hypothyroidism, and polycythemia vera, as well as high-dose ³¹P radiation exposure 45 years ago. There was no evidence of tuberculosis infection, hypothyroidism, malignant tumor, severe heart failure, uremia, trauma, severe bacterial or fungal infection, chronic myeloid leukemia, or bone marrow fibrosis after admission. The patient underwent pericardiocentesis twice. The pericardial effusion comprised exudate fluid with a high proportion of monocytes. The patient refused indwelling catheter drainage or pericardiectomy. The likely final diagnosis was recurrent chronic large idiopathic pericardial effusion.

Overview of Optimal Techniques for Pericardiocentesis in Contemporary Practice

PURPOSE OF REVIEW

This review summarizes the optimal techniques for the performance of pericardiocentesis in contemporary practice, highlighting the indications, contraindications, and techniques used. Routine pericardial catheter management and the diagnostic role of pericardial fluid analysis are described.

RECENT FINDINGS

Echocardiographic-guided pericardiocentesis should be considered the therapy of choice in current clinical practice and may be performed safely despite the presence of coagulopathy and thrombocytopenia in the hands of expert operators. Computed tomography (CT)-guided techniques may provide a useful adjunctive tool in patients with poor acoustic windows or complex loculated effusions. Conservative management utilizing pericardiocentesis may be considered in select patients with device lead and interventional-related pericardial effusions. Echocardiographic-guided pericardiocentesis with extended pericardial drainage (goal output < 50 mL/24 h) should be considered the standard of care in contemporary practice. Pericardial fluid analysis should be tailored based on the clinical history and appearances of the pericardial fluid.

Diagnostic performance of interferon-gamma release assay for diagnosis of tuberculous pericarditis: A meta-analysis

BACKGROUND

The diagnosis of tuberculous pericarditis is difficult to set, not only for its non-specific clinical presentation, but also for the lack of useful diagnostic tests. We comprehensively evaluate the overall diagnostic accuracy of Interferon-gamma release assays (IGRA) upon tuberculous pericarditis by meta-analysis.

METHODS

We searched PubMed, Embase and Cochrane Library database from the earliest available date of indexing through April 30, 2019. The study quality was evaluated using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS2) checklist. We determined the sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-) and constructed summary receiver operating characteristic curves parameters.

RESULTS

Across six results from five studies (415 patients), the pooled sensitivity for IGRA methods was 0.94 (95% confidence interval [CI]; 0.87-0.98) with heterogeneity (χ²  = 69.9, P = .01) and a pooled specificity of 0.94 (95% CI; 0.75-0.94) without heterogeneity (χ²  = 41.1, P = .13). Likelihood ratio (LR) syntheses gave an overall positive likelihood ratio (LR+) of 16.8 (95% CI; 8.0-35.4) and negative likelihood ratio (LR-) of 0.06 (95% CI; 0.03-0.13). The pooled diagnostic odds ratio was 278 (95% CI; 114-6806).

CONCLUSIONS

Interferon-gamma release assays demonstrated good sensitivity and specificity for diagnosis of tuberculous pericarditis. At present, the literature regarding remains the use of IGRA for diagnosis of tuberculous pericarditis still limited; thus, further large multicenter studies would be necessary to substantiate the diagnostic accuracy of IGRA test for the diagnosis of tuberculous pericarditis.

The critically ill patient with tuberculosis in intensive care: Clinical presentations, management and infection control

Tuberculosis (TB) is one of the top ten causes of death worldwide. In 2016, there were 490,000 cases of multi-drug resistant TB globally. Over 2 billion people have asymptomatic latent Mycobacterium tuberculosis infection. TB represents an important, but neglected management issue in patients presenting to intensive care units. Tuberculosis in intensive care settings may present as the primary diagnosis (active drug sensitive or resistant TB disease). In other patients TB may be an incidental co-morbid finding as previously undiagnosed sub-clinical or latent TB which may re-activate under conditions of stress and immunosuppression. In Sub-Saharan Africa, where co-infection with the human immunodeficiency virus and other communicable diseases is highly prevalent, TB is one of the most frequent clinical management issues in all healthcare settings. Acute respiratory failure, septic shock and multi-organ dysfunction are the most common reasons for intensive care unit admission of patients with pulmonary or extrapulmonary TB. Poor absorption of anti-TB drugs occurs in critically ill patients and worsens survival. The mortality of patients requiring intensive care is high. The majority of early TB deaths result from acute cardiorespiratory failure or septic shock. Important clinical presentations, management and infection control issues regarding TB in intensive care settings are reviewed.

Pyopericardium with Cardiac Tamponade in a Nigerian Child with Acute Osteomyelitis

In pyopericardium, pus accumulates in the pericardial space as a result of infection by pyogenic organisms, most common of which are Staphylococcus aureus and Mycobacterium tuberculosis. These patients are at risk of cardiac tamponade. Apart from pericardiocentesis in the management of these patients, definitive drug treatment may pose a formidable challenge in a setting of coinfection as in patients with tuberculosis who are predisposed to secondary bacterial infections. This was the case of our patient. We here highlight the challenges faced with etiologic diagnosis in resource-limited settings.

Rapid diagnosis of tuberculous pericarditis by ELISPOT assay

We describe a case in which the rapid diagnosis of tuberculous pericarditis was made using the Mycobacterium tuberculosis (MTB)-specific enzyme-linked immunospot (ELISPOT) assay on pericardial effusion mononuclear cells (PEMCs). The analysis of MTB-specific T-cells in PEMCs by ELISPOT may be useful for rapid decision-making in anti-tuberculous treatment.

[New possibilities of diagnostics and therapy of pericarditis]

Pericarditis is an inflammatory disorder of the pericardium with or without an associated pericardial effusion. The diagnosis is based on the clinical manifestations and typical ECG changes. Echocardiography is essential to reveal the size of the pericardial effusion and to determine its hemodynamic significance. The precise etiology of pericarditis may be established by pericardiocentesis, pericardioscopy and targeted biopsy and consecutive pericardial fluid and biopsy analysis by molecular biology, cytology, microbiology and immunological techniques. Non steroidal anti-inflammatory drugs and/or colchicine are the mainstay of anti-inflammatory treatment of pericarditis. Systemic corticoid treatment should be restricted to patients with associated autoimmune disorder, relapsing pericarditis and as a complementary therapy in tuberculous pericarditis. In autoreactive pericarditis intrapericardial instillation of triamcinolone is effective with few side effects. In malignant pericarditis the intrapericardial administration of cisplatin prevents early recurrences.

Molecular detection of invasive aspergillosis in hematologic malignancies

BACKGROUND

Aspergillus species are the most frequent causes of invasive mold infections in immunocompromised patients, particularly those who underwent chemotherapy for hematologic malignancies. The aim of this study was to determine the incidence and efficiency of the PCR-enzyme linked immunosorbent assay method (PCR-ELISA) for early detection of Aspergillus species in patients with hematologic malignancies.

PATIENTS AND METHODS

From 2004 to 2006, 194 patients with hematologic malignancies (who received chemotherapy) were evaluated for invasive aspergillosis (IA) in Shiraz, southern Iran. Ethylenediaminetetraacetic acid anticoagulant whole blood samples were collected prospectively once a week and stored at -20 degrees C until examination. All collected blood samples were assayed for the presence of the bands on ethidium bromide stained gel and for hybridization.

RESULTS

The female-to-male ratio was 61:133, the mean age of patients was 33.7 years, and mean of hospitalization period was 21.2 days. PCR-ELISA was positive in 14 (7.2%) patients who exhibited clinical and radiologic signs of IA. The etiologic agents were Aspergillus flavus (11 cases) and Aspergillus fumigatus (three cases). The mean time of positivity of PCR-ELISA in the blood before the appearance of clinical signs was 12.6 days. PCR was found to be the earliest indicator of IA preceding nonspecific clinical and radiologic findings. The sensitivity, specificity, positive, and negative predictive values of PCR-ELISA to detect DNA-specific for Aspergillus species in patients with proven and probable IA were 66%, 96%, 62.5%, and 97%, respectively. In case patients were treated with antifungal drugs, and the treatment was successful, fungal PCR assay became negative after 14 days and if the treatment failed, assay was positive until death.

CONCLUSIONS

We demonstrated, in the present study, the incidence of IA in leukemic patients and the usefulness of molecular assay for early diagnosis and monitoring of the treatment of IA.

Proteomic analysis of pericardial effusion: Characteristics of tuberculosis-related proteins

The aim of this study has been designed to identify the tuberculosis (TB)-related proteins in pericardial effusion by proteomic approaches. TB is one of the major infectious diseases causing pericardial effusion. This study details protein profiles in pericardial effusion from three TB patients and three heart failure patients. Pericardial effusions were analyzed using 2-DE combined with the nano-HPLC-ESI-MS/MS. Eleven protein spots with differential expression in pericardial effusion were identified between the two groups of TB and heart failure patients (the control group). Seven protein spots were upregulated and four were downregulated. The composition of the pericardial effusion proteome may reflect the pathophysiological conditions affecting the progression of tuberculous pericarditis. The proteins in the tuberculous pericardial effusion with differential expression may serve as new and direct indicators of drug treatment. A possible conclusion is indicated that fibrinogen may play an important role for fibrin assembly in tuberculous pericardial effusion.

A modern approach to tuberculous pericarditis

The human immunodeficiency virus (HIV) epidemic has been associated with an increase in all forms of extrapulmonary tuberculosis including tuberculous pericarditis. Tuberculosis is responsible for approximately 70% of cases of large pericardial effusion and most cases of constrictive pericarditis in developing countries, where most of the world's population live. However, in industrialized countries, tuberculosis accounts for only 4% of cases of pericardial effusion and an even smaller proportion of instances of constrictive pericarditis. Tuberculous pericarditis is a dangerous disease with a mortality of 17% to 40%; constriction occurs in a similar proportion of cases after tuberculous pericardial effusion. Early diagnosis and institution of appropriate therapy are critical to prevent mortality. A definite or proven diagnosis is based on demonstration of tubercle bacilli in pericardial fluid or on histologic section of the pericardium. A probable or presumed diagnosis is based on proof of tuberculosis elsewhere in a patient with otherwise unexplained pericarditis, a lymphocytic pericardial exudate with elevated biomarkers of tuberculous infection, and/or appropriate response to a trial of antituberculosis chemotherapy. Treatment consists of 4-drug therapy (isoniazid, rifampicin, pyrazinamide, and ethambutol) for 2 months followed by 2 drugs (isoniazid and rifampicin) for 4 months regardless of HIV status. It is uncertain whether adjunctive corticosteroids are effective in reducing mortality or pericardial constriction, and their safety in HIV-infected patients has not been established conclusively. Surgical resection of the pericardium is indicated for those with calcific constrictive pericarditis or with persistent signs of constriction after a 6 to 8 week trial of antituberculosis treatment in patients with noncalcific constrictive pericarditis.

The usefulness of adenosine deaminase in the diagnosis of tuberculous pericarditis

The objective of this study was to evaluate the adenosine deaminase (ADA) activity usefulness in the diagnosis of tuberculous pericarditis (TP), comparing its value with pericardial effusions (PE) caused by other pericardial diseases. A retrospective case-control study was conducted with nine cases of TP and 39 other than TP diseases (12 neoplastic, 11 septic and 16 unknown origin). Every patient included in this study had PE samples submitted to ADA activity measures and microbiological analysis, and then had pericardial tissue samples submitted to microbiological and histopathological examination. Considering the value of 40 U/L as the cut-off for the diagnosis of TP, the specificity and sensitivity were respectively of 72% and 89%. The specificity of ADA activity for the TP was best applied in the differential diagnosis from PE of unknown origin. The present study demonstrates the clinical value of the measurement of ADA activity in PE in the diagnosis of TP.

Adenosine deaminase and tuberculous pericarditis--a systematic review with meta-analysis

BACKGROUND

Adenosine deaminase (ADA) activity in pericardial fluid is a valuable aid in the diagnosis of tuberculous pericarditis (TP), but there is no systematic review performed to evaluate the benefits of ADA activity as an adjunctive test for TP diagnosis. The objective of this systematic review was to evaluate the utility of ADA activity as a diagnostic marker of TP on patients presenting with pericardial effusion.

METHODS

MEDLINE, LILACS and Cochrane Library databases (1980-2005) searches to identify articles related to adenosine deaminase activity on TP diagnosis. Articles with patients with at least one TP diagnostic criteria were included. The controls were patients with other pericardial diseases with moderate or large pericardial effusion. To calculate the sensitivity, specificity, as well as positive and negative likelihood ratios we extracted the total number of confirmed TP cases over all patients with pericardial effusion as well as the number of cases with ADA activity values of 40 U/L and over.

RESULTS

Thirty one studies met our initial inclusion criteria and five articles were selected. The heterogeneity limited the specificity analysis (p=0.004). The method yielded a sensitivity and specificity of 88% and 83%, respectively. The SROC curve presented an area with a tendency towards 1 (value of 0.9539) and corroborates the diagnostic value of ADA activity.

CONCLUSIONS

The present study confirms the clinical value of ADA activity as adjunctive diagnostic marker of TP among other causes of pericardial effusion.

Bacterial pericarditis: diagnosis and management

Bacterial pericarditis occurs by direct infection during trauma, thoracic surgery, or catheter drainage, by spread from an intrathoracic, myocardial, or subdiaphragmatic focus, and by hematogenous dissemination. The frequent causes are Staphylococcus and Streptococcus (rheumatic pancarditis), Haemophilus, and M. tuberculosis. In AIDS pericarditis, the incidence of bacterial infection is much higher than in the general population, with a high proportion of Mycobacterium avium-intracellulare infection. Purulent pericarditis is the most serious manifestation of bacterial pericarditis, characterized by gross pus in the pericardium or microscopically purulent effusion. It is an acute, fulminant illness with fever in virtually all patients. Chest pain is uncommon. Purulent pericarditis is always fatal if untreated. The mortality rate in treated patients is 40%, and death is mostly due to cardiac tamponade, systemic toxicity, cardiac decompensation, and constriction. Tuberculous infection may present as acute pericarditis, cardiac tamponade, silent (often large) relapsing pericardial effusion, effusive-constrictive pericarditis, toxic symptoms with persistent fever, and acute, subacute, or chronic constriction. The mortality in untreated patients approaches 85%. Urgent pericardial drainage, combined with intravenous antibacterial therapy (e.g. vancomycin 1g twice daily, ceftriaxone 1-2g twice daily, and ciprofloxacin 400 mg/day) is mandatory in purulent pericarditis. Irrigation with urokinase or streptokinase, using large catheters, may liquify the purulent exudate, but open surgical drainage is preferable. The initial treatment of tuberculous pericarditis should include isoniazid 300 mg/day, rifampin 600 mg/day, pyrazinamide 15-30 mg/kg/day, and ethambutol 15-25 mg/kg/day. Prednisone 1-2 mg/kg/day is given for 5-7 days and progressively reduced to discontinuation in 6-8 weeks. Drug sensitivity testing is essential. Pericardiectomy is reserved for recurrent effusions or continued elevation of central venous pressure after 4-6 weeks of antituberculous and corticosteroid therapy.

Tuberculous pericarditis

BACKGROUND

The incidence of tuberculous pericarditis is increasing in Africa as a result of the human immunodeficiency virus (HIV) epidemic. The primary objective of this article was to review and summarize the literature on the pathogenesis, diagnosis, and management of tuberculous pericarditis.

METHODS AND RESULTS

We searched MEDLINE (January 1966 to May 2005) and the Cochrane Library (Issue 1, 2005) for information on relevant references. A "definite" diagnosis of tuberculous pericarditis is based on the demonstration of tubercle bacilli in pericardial fluid or on a histological section of the pericardium; "probable" tuberculous pericarditis is based on the proof of tuberculosis elsewhere in a patient with otherwise unexplained pericarditis, a lymphocytic pericardial exudate with elevated adenosine deaminase levels, and/or appropriate response to a trial of antituberculosis chemotherapy. Treatment consists of the standard 4-drug antituberculosis regimen for 6 months. It is uncertain whether adjunctive corticosteroids are effective in reducing mortality or progression to constriction. Surgical resection of the pericardium remains the appropriate treatment for constrictive pericarditis. The timing of surgical intervention is controversial, but many experts recommend a trial of medical therapy for noncalcific pericardial constriction, and pericardiectomy in nonresponders after 4 to 8 weeks of antituberculosis chemotherapy.

CONCLUSIONS

Research is needed to improve the diagnosis, assess the effectiveness of adjunctive steroids, and determine the impact of HIV infection on the outcome of tuberculous pericarditis.

A review of tuberculosis: reflections on the past, present and future of a global epidemic disease

Tuberculosis remains the leading cause of death worldwide from a single infectious organism. Approximately 32% of the world's population is infected and an estimated two million people die annually from this treatable disease. Over the past 50 years, with medical treatment and standard public health practices, tuberculosis diminished in developed countries and resulted in a loss of interest and funding for research in improving diagnostic and treatment options. In developing countries, efforts including BCG vaccination have failed to control tuberculosis and the disease continues to spread as the world becomes more globalized. At the same time, multidrug resistant tuberculosis has emerged, challenging even the most advance treatment centers. Better diagnostic techniques, control measures and treatment options are desperately needed but advances require worldwide commitment to battle this age-old disease.

Housekeeping gene variability in normal and cancerous colorectal, pancreatic, esophageal, gastric and hepatic tissues

Careful normalization is essential for the accurate quantitation of mRNA levels in biopsy-sized tissue samples. Commonly, normalization of the target gene with an endogenous standard, mainly housekeeping genes (HKGs), is applied. However, differences in the expression levels of endogenous reference genes have been reported between different tissues and pathological states. Therefore, we were challenged to identify a set of endogenous reference genes whose mRNA expression levels would not change significantly between normal and cancerous tissues. Quantitative real-time PCR (Q-RT-PCR) analysis was applied to evaluate the variability in gene expression among 21 classical housekeeping genes in colorectal, pancreatic, esophageal and gastric cancer as well as in liver metastases in comparison to the corresponding normal tissue. Our results indicated that some housekeeping genes were candidates with relatively stable gene expression in several of the investigated tissues but for most of the HKGs under investigation our data have revealed distinct differences in the extent of variability in gene expression between the different tissues and pathological states. However, for each of the five tissues investigated we found a group of genes that were expressed at a constant level thus representing a panel of candidates that we can recommend as housekeeping genes in the respective tissue types. In summary, our results can be used as guidance for other scientists studying various carcinomas for tissue-specific selection of the optimal housekeeping gene (HKG) to be used in normalizing target gene expression.

Diagnosis of tuberculous aetiology in pericardial effusions

The diagnosis of tuberculous aetiology in pericardial effusions is important since the prognosis is excellent with specific treatment. The clinical features may not be distinctive and the diagnosis could be missed particularly with tamponade. With the spread of HIV infection the incidence has increased. The diagnosis largely depends on histopathology of the pericardial tissue or culture of Mycobacterium tuberculosis from this tissue or fluid, but patients without haemodynamic compromise do not require pericardiocentesis. Histopathology may, however, show non-specific findings in a significant number. This review is an update on the diagnostic difficulties, current research, and criteria for diagnosis.

The common and distinct target genes of the p53 family transcription factors

p53 is the most commonly mutated gene in human cancer. After activation by cellular stresses such as DNA damage or oncogene activation, p53, a sequence-specific DNA-binding protein, induces the expression of target genes which mediate tumor suppression. Two recently identified p53 homologues, p63 and p73, appear to function similarly to p53, that is, they both activate target gene expression and suppress cell growth when overexpressed; however, the p63 and p73 genes are rarely mutated in human cancer and do not adhere to Knudson's classical model of a tumor suppressor gene. Recently, exciting observations suggest nonoverlapping functions for the family members. Herein, we outline the recent literatures identifying and characterizing both the common and distinct target genes of the p53 family transcription factors in relation to their signaling pathways.