Efficacy of low-dose lung radiotherapy in the management of COVID-19 patients: a randomised, open-label study.

OBJECTIVE: Evaluate role of low-dose radiotherapy (LDRT) in COVID-19 pneumonia. METHODS: Sixty-five patients 40 years or older tested positive for COVID-19 reverse transcriptase-polymerase chain reaction with mild to moderate acute respiratory distress syndrome (ARDS), were randomised 1:1, from 4 June 2021, to either best standard of care (control arm) according to the Indian Council of Medical Research guidelines or a single dose of LDRT (LDRT-0.5Gy) to both lungs along with best standard of care (experimental arm). The primary outcome was either progression to severe disease (PaO2/FiO2 ratio <100 mmHg) within 28 days of randomisation or all-cause mortality at 28 days. If the primary outcome could have been prevented, it was considered "favourable"; if not, it was considered "unfavourable." RESULTS: Thirty-three patients were allocated to experimental arm, 32 to control arm. An intention to treat analysis was performed. Unfavourable outcome was seen in 5 (15.2%) patients in experimental arm, vs , 12 (37.5%) patients in control arm, odds of an unfavourable outcome in experimental arm were 0.3, 95% CI 0.09-0.97; two-sided p = 0.04. Four and five patients died in experimental and control arm, respectively. No radiation-induced toxicity was observed. CONCLUSION: LDRT reduced the number of patients with unfavourable outcome at 28 days. ADVANCES IN KNOWLEDGE: One of the few randomised studies showing reduced unfavourable outcome in mild to moderate ARDS COVID-19 patients receiving LDRT.CTRI/2021/06/034001, Clinical Trials Registry - India (ICMR-NIMS).

Molecular Characterization and Identification of Potential Inhibitors for 'E' Protein of Dengue Virus.

Dengue is an arthropod-borne acute febrile illness caused by Dengue Virus (DENV), a member of Flaviviridae. Severity of the infection ranges from mild self-limiting illness to severe life-threatening hemorrhagic fever (DHF) and dengue shock syndrome (DSS). To date, there is no specific antiviral therapy established to treat the infection. The current study reports the epidemiology of DENV infections and potential inhibitors of DENV 'E' protein. Among the various serotypes, DENV-2 serotype was observed more frequently, followed by DENV-4, DENV-1, and DENV-3. New variants of existing genotypes were observed in DENV-1, 2, and 4 serotypes. Predominantly, the severe form of dengue was attributable to DENV-2 infections, and the incidence was more common in males and pediatric populations. Both the incidence and the disease severity were more common among the residents of non-urban environments. Due to the predominantly self-limiting nature of primary dengue infection and folk medicine practices of non-urban populations, we observed a greater number of secondary dengue cases than primary dengue cases. Hemorrhagic manifestations were more in secondary dengue in particularly in the pediatric group. Through different computational methods, ligands RGBLD1, RGBLD2, RGBLD3, and RGBLD4 are proposed as potential inhibitors in silico against DENV-1, -2, -3, and -4 serotypes.

Spatial analysis of chronic obstructive pulmonary disease and its risk factors in an urban area of Trivandrum, Kerala, India.

Background: Chronic obstructive pulmonary disease (COPD) is the second leading cause of death in India. The objective of this study was to map COPD cases and its risk factors and to determine the association between them using geographic information system (GIS) in a semi-urban area of Trivandrum, South India. Materials and Methods: This community-based cross-sectional, descriptive study (n = 494) was conducted in a subcenter area of a primary health center. Location was mapped and COPD population screener questionnaire was administered to all the study subjects enrolled by census method. Lifetime firewood exposure (person-hours) and tobacco smoking were enquired and distance from road was mapped using portable differential global positioning system. The association with COPD was assessed by kriging and hotspot analysis using ArcGIS software. Results: The prevalence of COPD (6.5%) was comparable to national prevalence estimates. Spatial maps showed COPD case clustering in areas with higher firewood exposure, greater smoking exposure, and in households with closer proximity to local roads. A particular high-risk cluster was obtained which had a significant association with all the risk factors. Conclusion: GIS technology is useful in identification of spatial clustering of COPD cases and its environmental risk factors, making it an important tool for targeted interventions for COPD.

Serum procalcitonin as a biomarker of bloodstream infection & focal bacterial infection in febrile patients.

Background & objectives: Bacteraemia is a serious form of infection in patients presenting with fever, thus, there is a necessity for a biomarker for rapid diagnosis of bacteraemia in such patients to make better therapeutic decisions. This study was conducted to measure the serum procalcitonin (PCT) levels at the time of initial presentation as a biomarker for identifying bacteraemia and as a predictor of mortality in patients admitted with acute fever. Methods: Four hundred and eighty patients, who presented with acute fever requiring admission to a tertiary care teaching hospital in south India, were prospectively studied. All patients were evaluated with a detailed history, physical examination, laboratory and imaging studies. Baseline serum PCT was measured for each patient within six hours of admission. Results: Among patients with single infectious cause (n=275), significantly higher median serum PCT levels were evident in bacteraemia compared to leptospirosis (P=0.002), dengue (P <0.001), scrub typhus (P <0.001) and evident focus of infection without bacteraemia (P=0.036). By receiver-operator characteristic curve analysis, at a cut-off value of >3.2 ng/ml, the sensitivity and specificity of serum PCT levels in predicting bacteraemia were 81.1 and 63.3 per cent, respectively. As per the worst-case scenario analysis, 91 (18.9%) patients had a poor outcome and these had significantly higher median serum PCT levels compared to survivors (n=389) [9.46 (2.03-44.4) vs. 1.23 (0.34-7.645); P <0.001]. At a cut-off value of >3.74 ng/ml, serum PCT levels at initial presentation predicted in-hospital mortality with a sensitivity and specificity of 67 and 67.5 per cent, respectively. Interpretation & conclusions: Our observations suggest that serum PCT level may be a useful biomarker for identifying bacteraemia as well as predicting mortality in patients with acute fever requiring admission to hospital.

Impact of nicotine replacement therapy as an adjunct to anti-tuberculosis treatment and behaviour change counselling in newly diagnosed pulmonary tuberculosis patients: an open-label, randomised controlled trial.

We evaluated the impact of intensive smoking cessation activities as an adjunct to anti-tuberculosis treatment on patient-related treatment outcomes. In this open-label, randomised controlled trial, self-reporting smokers with pulmonary tuberculosis who initiated standard anti-tuberculosis treatment were randomised to either nicotine replacement therapy and behaviour change counselling (n = 400) or counselling alone (n = 400) provided at baseline and two follow-up visits. The primary outcomes were change in TBscore at 24-weeks and culture conversion at 8-weeks. Biochemical smoking quit rates defined as serum cotinine levels <10 ng/mL and/or exhaled carbon monoxide levels <6 ppm (47·8% vs 32·4%, p-value =< 0·001) and self-reported quit rates (69.3% vs 38·7%, p-value =< 0·001) were significantly higher in the intervention arm at 24-weeks. Though the TBscores at 24 weeks (95% CI) were lower in the intervention arm [2·07 (1·98, 2·17) versus 2.12 (2·02, 2·21)], the difference was not clinically meaningful. Patients in the control arm required treatment extension more often than intervention arm (6·4% vs 2·6%, p-value = 0·02). Combining nicotine replacement therapy with behaviour change counselling resulted in significantly higher quit rates and lower cotinine levels, however, impact on patient-related (TBscore) or microbiological outcomes (culture conversion) were not seen.

Outcome and management of spinal tuberculosis according to severity at a tertiary referral center.

OBJECTIVE: Anti-tuberculosis (TB) treatment remains the mainstay of treatment of spinal TB. There is a lack of consensus regarding the timing of interventional procedures and surgery in the patients with spinal TB. This study aims to prospectively study the clinical outcome and management in patients presenting with spinal TB at our tertiary referral center and teaching hospital. METHODS: Data were collected prospectively from 48 patients treated for spinal TB presenting to us from August 2011 to December 2012. All the patients were followed-up for the duration of anti-TB treatment. RESULTS: The categorization of patients into different management groups was based on the clinical and radiological findings at the time of diagnosis. The patients with mild disease (n = 23) were successfully managed with anti-TB treatment alone. The other 25 patients needed an intervention either in the form of pigtail catheter drainage of the paravertebral collection (n = 18) or an extensive surgical debridement followed by the fusion techniques (n = 7). All the patients responded well to the treatment, and there were no significant complications in any of the patients. It had been observed that various stages of spinal TB demand different approaches for the treatment in the form of either chemotherapy alone, chemotherapy with pigtail drainage of the paravertebral collection, or surgery in conjunction with chemotherapy. CONCLUSIONS: Judicious use of pigtail drainage and surgical intervention in addition to anti TB treatment can be rewarding in the patients with spinal TB.

Miliary Tuberculosis.

Miliary tuberculosis (TB) results from a massive lymphohematogenous dissemination of Mycobacterium tuberculosis bacilli and is characterized by tiny tubercles evident on gross pathology resembling millet seeds in size and appearance. The global HIV/AIDS pandemic and widespread use of immunosuppressive drugs and biologicals have altered the epidemiology of miliary TB. Considered to be predominantly a disease of infants and children in the pre-antibiotic era, miliary TB is increasingly being encountered in adults as well. The clinical manifestations of miliary TB are protean and nonspecific. Atypical clinical presentation often delays the diagnosis. Clinicians, therefore, should have a low threshold for suspecting miliary TB. Focused, systematic physical examination helps in identifying the organ system(s) involved, particularly early in TB meningitis, as this has therapeutic significance. Fundus examination for detecting choroid tubercles offers a valuable clinical clue for early diagnosis, as their presence is pathognomonic of miliary TB. Imaging modalities help in recognizing the miliary pattern, defining the extent of organ system involvement. Examination of sputum, body fluids, image-guided fine-needle aspiration cytology or biopsy from various organ sites, needle biopsy of the liver, bone marrow aspiration, and biopsy should be done to confirm the diagnosis. Cytopathological, histopathological, and molecular testing (e.g., Xpert MTB/RIF and line probe assay), mycobacterial culture, and drug susceptibility testing must be carried out as appropriate and feasible. Miliary TB is uniformly fatal if untreated; therefore, early initiation of specific anti-TB treatment can be lifesaving. Monitoring for complications, such as acute kidney injury, air leak syndromes, acute respiratory distress syndrome, adverse drug reactions such as drug-induced liver injury, and drug-drug interactions (especially in patients coinfected with HIV/AIDS), is warranted.

Evaluation of activity of hypothalamo-pituitary-gonadal axis in postmenopausal women suffering from severe acute illness.

BACKGROUND & OBJECTIVES: Postmenopausal women constitute an ideal model for studying the extent of hypothalamo-pituitary gonadal (HPG) axis suppression in critical illness as the gonadotropins are normally high and non-cyclical in them. The objective was to assess the impact of acute severe illness in postmenopausal women on the HPG axis and the activities of the hypothalamo-pituitary-adrenal (HPA), the hypothalamo- pituitary-thyroid (HPT) axes; and levels of serum prolactin, by comparison between critically ill postmenopausal women and otherwise healthy postmenopausal women. METHODS: Thirty five consecutive postmenopausal women older than 60 yr admitted to medical intensive care with a s0 implified a0 cute p0 hysiology s0 core II (SAPS II) more than 30 were included. On day five of their in-hospital stay, blood samples were collected for oestradiol, luteinizing hormone (LH), follicle stimulating hormone (FSH), cortisol, androstenedione, prolactin and thyroid profile. Thirty five apparently healthy postmenopausal women were selected as controls. RESULTS: Levels of LH, FSH, thyrotropin, free thyroxin (fT 4 ) and free tri-iodothyronine (fT 3 ) were lower while oestradiol, cortisol and dehydroepiandrosterone were higher among patients in comparison to healthy controls. Prolactin levels were similar in patients and controls. Among sick patients both FSH and fT 4 showed a negative correlation ( P<0.05) with the SAPS II score. INTERPRETATION & CONCLUSIONS: In critically ill postmenopausal women, paradoxically elevated oestrogen levels despite gonadotropin suppression suggests a non-ovarian origin. Prolactin remained unaltered in patients despite their illness, possibly reflecting atrophy of lactotrophs in menopause.

Miliary tuberculosis: A new look at an old foe.

Miliary tuberculosis (TB), is a fatal form of disseminated TB characterized by tiny tubercles evident on gross pathology similar to innumerable millet seeds in size and appearance. Global HIV/AIDS pandemic and increasing use of immunosuppressive drugs have altered the epidemiology of miliary TB. Keeping in mind its protean manifestations, clinicians should have a low threshold for suspecting miliary TB. Careful physical examination should focus on identifying organ system involvement early, particularly TB meningitis, as this has therapeutic significance. Fundus examination for detecting choroid tubercles can help in early diagnosis as their presence is pathognomonic of miliary TB. Imaging modalities help in recognizing the miliary pattern, define the extent of organ system involvement and facilitate image guided fine-needle aspiration cytology or biopsy from various organ sites. Sputum or BAL fluid examination, pleural, pericardial, peritoneal fluid and cerebrospinal fluid studies, fine needle aspiration cytology or biopsy of the lymph nodes, needle biopsy of the liver, bone marrow aspiration and biopsy, testing of body fluids must be carried out. GeneXpert MTB/RIF, line probe assay, mycobacterial culture and drug-susceptibility testing must be carried out as appropriate and feasible. Treatment of miliary TB should be started at the earliest as this can be life saving. Response to first-line anti-TB drugs is good. Screening and monitoring for complications like acute respiratory distress syndrome (ARDS), adverse drug reactions like drug-induced liver injury, drug-drug interactions, especially in patients co-infected with HIV/AIDS, are warranted. Sparse data are available from randomized controlled trials regarding optimum regimen and duration of anti-TB treatment.

Consensus and evidence-based Indian initiative on obstructive sleep apnea guidelines 2014 (first edition).

Obstructive sleep apnea (OSA) and obstructive sleep apnea syndrome (OSAS) are subsets of sleep-disordered breathing. Awareness about OSA and its consequences among the general public as well as the majority of primary care physicians across India is poor. This necessitated the development of the Indian initiative on obstructive sleep apnea (INOSA) guidelines under the auspices of Department of Health Research, Ministry of Health and Family Welfare, Government of India. OSA is the occurrence of an average five or more episodes of obstructive respiratory events per hour of sleep with either sleep-related symptoms or co-morbidities or ≥15 such episodes without any sleep-related symptoms or co-morbidities. OSAS is defined as OSA associated with daytime symptoms, most often excessive sleepiness. Patients undergoing routine health check-up with snoring, daytime sleepiness, obesity, hypertension, motor vehicular accidents, and high-risk cases should undergo a comprehensive sleep evaluation. Medical examiners evaluating drivers, air pilots, railway drivers, and heavy machinery workers should be educated about OSA and should comprehensively evaluate applicants for OSA. Those suspected to have OSA on comprehensive sleep evaluation should be referred for a sleep study. Supervised overnight polysomnography is the "gold standard" for evaluation of OSA. Positive airway pressure (PAP) therapy is the mainstay of treatment of OSA. Oral appliances (OA) are indicated for use in patients with mild to moderate OSA who prefer OA to PAP, or who do not respond to PAP or who fail treatment attempts with PAP or behavioral measures. Surgical treatment is recommended in patients who have failed or are intolerant to PAP therapy.

Consensus & evidence-based INOSA Guidelines 2014 (first edition).

Obstructive sleep apnoea (OSA) and obstructive sleep apnoea syndrome (OSAS) are subsets of sleep-disordered breathing. Awareness about OSA and its consequences amongst the general public as well as the majority of primary care physcians across India is poor. This necessiated the development of the INdian initiative on Obstructive sleep apnoea (INOSA) guidelines under the auspices of Department of Health Research, Ministry of Health & Family Welfare, Government of India. OSA is the occurrence of an average five or more episodes of obstructive respiratory events per hour of sleep with either sleep related symptoms or co-morbidities or ≥ 15 such episodes without any sleep related symptoms or co-morbidities. OSAS is defined as OSA associated with daytime symptoms, most often excessive sleepiness. Patients undergoing routine health check-up with snoring, daytime sleepiness, obesity, hypertension, motor vehicular accidents and high risk cases should undergo a comprehensive sleep evaluation. Medical examiners evaluating drivers, air pilots, railway drivers and heavy machinery workers should be educated about OSA and should comprehensively evaluate applicants for OSA. Those suspected to have OSA on comprehensive sleep evaluation should be referred for a sleep study. Supervised overnight polysomnography (PSG) is the "gold standard" for evaluation of OSA. Positive airway pressure (PAP) therapy is the mainstay of treatment of OSA. Oral appliances are indicated for use in patients with mild to moderate OSA who prefer oral appliances to PAP, or who do not respond to PAP or who fail treatment attempts with PAP or behavioural measures. Surgical treatment is recommended in patients who have failed or are intolerant to PAP therapy.

Challenges in the diagnosis & treatment of miliary tuberculosis.

Miliary tuberculosis (TB) is a potentially lethal disease if not diagnosed and treated early. Diagnosing miliary TB can be a challenge that can perplex even the most experienced clinicians. Clinical manifestations are nonspecific, typical chest radiograph findings may not be evident till late in the disease, high resolution computed tomography (HRCT) shows randomly distributed miliary nodules and is relatively more sensitive. Ultrasonography, CT and magnetic resonance imaging (MRI) are useful in discerning the extent of organ involvement by lesions of miliary TB in extra-pulmonary locations. Fundus examination for choroid tubercles, histopathological examination of tissue biopsy specimens, conventional and rapid culture methods for isolation of Mycobacterium tuberculosis, drug-susceptibility testing, along with use of molecular biology tools in sputum, body fluids, other body tissues are useful in confirming the diagnosis. Although several prognostic markers have been described which predict mortality, yet untreated miliary TB has a fatal outcome within one year. A high index of clinical suspicion and early diagnosis and timely institution of anti-tuberculosis treatment can be life-saving. Response to first-line anti-tuberculosis drugs is good but drug-induced hepatotoxicity and drug-drug interactions in human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) patients pose significant problems during treatment. However, sparse data are available from randomized controlled trials to define the optimum regimen and duration of treatment in patients with drug-sensitive as well as drug-resistant miliary TB, including those with HIV/AIDS.

Acute accidental exposure to chlorine gas: clinical presentation, pulmonary functions and outcomes.

BACKGROUND: To study the clinical presentation, pulmonary functions and outcomes in subjects who were accidentally exposed to chlorine gas. METHODS: Prospective observational study of 64 patients who sustained acute accidental exposure to chlorine gas during a leak in the chlorination system of the public bathing pool of a temple. RESULTS: The major presenting symptoms and signs included acute dyspnoea (100%), chest discomfort (100%), cough (97%), eye irritation (88%), giddiness (72%), vomiting (46%), and heaviness in the head (44%); tachycardia (100%), tachypnoea (96%) and polyphonic wheezing (28%). All patients were managed in the emergency room with humidified oxygen inhalation and beta-2 agonist nebulisation and 52 were discharged within six hours. Twelve patients were severely affected and required hospitalisation; three of them were admitted into the intensive care unit. Three patients developed pulmonary oedema six to eight hours following admission. Pulmonary function testing (n = 12) at presentation revealed obstructive defect in eight and mixed obstructive-cum-restrictive defect in four patients. The mean duration of hospital stay was 5.1 +/- 2.1 days. None of the patients died. Reactive airway dysfunction syndrome (RADS) was observed in three of the 12 hospitalised patients, who complained of manifested persistent cough that lasted for three months period following discharge. Serial pulmonary functions recovered to normal range by the end of the six months in all patients and remained so at one-year follow-up. CONCLUSION: Acute exposure to chlorine gas is an uncommon, but important public health hazard and can cause RADS, acute lung injury and pulmonary function abnormalities, which are reversible on prompt and appropriate management.

Fibreoptic bronchoscopy in the diagnosis of sputum smear-negative pulmonary tuberculosis: current status.

Sputum smear-negative pulmonary tuberculosis (SSN-PTB) is a common problem faced by clinicians. Performing fibreoptic bronchoscopy (FOB), and subjecting the bronchoscopic secretions/transbronchial lung biopsy (TBLB) material to conventional diagnostic methods of smear, mycobacterial culture and histopathology appears to be helpful in the diagnosis of SSN-PTB. Application of polymerase chain reaction (PCR) may be helpful as an adjunctive method in the appropriate clinical setting. The FOB facilitates rapid diagnosis and offers the additional advantage of the diagnosis of several conditions that may mimic PTB. However, FOB is an invasive procedure, and is associated with the risk of transmission of tuberculosis (TB) and other infections. It is costly, and is not widely available in the developing countries. In developed countries with no limitations on resources, early FOB seems to be the best course of action in a patient with suspected SSN-PTB. In resource-poor settings, where transmission of TB is high, sputum induction with hypertonic saline can be useful in adding to the diagnostic yield. If the TB suspect still remains induced sputum smear-negative, and if the pre-test probability of the patient having PTB is high, starting antituberculosis treatment (ATT) and closely monitoring the patient and reserving FOB to those patients who do not seem to improve/deteriorate or those who have a negative spontaneously expectorated/induced sputum culture (if performed and available) seems to be a practically useful approach. Proper precautions must be followed to disinfect the bronchoscope in between use so as to minimise the risk of nosocomial transmission of infection.

Myasthenic crisis-like syndrome due to Cleistanthus collinus poisoning.

Poisoning with Cleistanthus collinus frequently causes cardiac manifestations such as rhythm disturbances and also results in other manifestations such as metabolic acidosis and hypokalemia. We present the case of a patient who presented with a rare myasthenic crisis-like syndrome requiring assisted ventilation due to Cleistanthus collinus poisoning, which responded to treatment with neostigmine.

Aetiology of peripheral lymphadenopathy in adults: analysis of 1724 cases seen at a tertiary care teaching hospital in southern India.

BACKGROUND: In patients presenting with peripheral lymphadenopathy, excision biopsy of the most accessible lymph node provides material to establish an early diagnosis, and is important in the management of these patients. METHODS: A retrospective study was done of 1724 lymph node biopsy specimens obtained from adult patients and submitted for histopathological examination over a 12-year period. RESULTS: About one-third (n = 614; 35.6%) of these patients had non-specific lymphadenitis. This included a heterogeneous group of disorders comprising benign follicular hyperplasia, reactive hyperplasia, marked follicular hyperplasia and reactive sinus histiocytosis. Tuberculosis lymphadenitis (n = 540; 31.3%) and malignancy (n = 447; 25.9%) were the other common causes. Of the 540 patients with tuberculosis lymphadenitis, the human immunodeficiency virus (HIV) status was tested in 424 (78.5%) patients; of these, 34 patients (8%) were HIV-seropositive. Epithelioid granulomas with caseation necrosis were more frequently seen in HIV-seronegative patients compared with HIV-seropositive ones (chi2 = 54.66; p < 0.001 ). In HIV-seropositive patients, multiple sites of lymph node involvement (chi2 = 40.597; p < 0.001), suppurative type with adjacent necrosis and panniculitis (chi2 = 68.128; p < 0.001), and non-reactive histological types (chi2 = 109.234; p < 0.001) were more commonly seen compared with HIV-seronegative patients. Kikuchi-Fujimoto disease (n = 36), Kimura disease (n = 7), Rosai-Dorfman disease (n = 6), were rare aetiological causes that have been infrequently reported from India. CONCLUSION: Awareness of the characteristic histopathological findings and uncommon aetiological causes of peripheral lymphadenopathy may spare patients from unnecessary evaluation and treatment. In HIV-positive patients, lymph node tuberculosis may be histopathologically unusual and may be suppurative or non-reactive in nearly one-third of patients.

Lethal interaction: the colliding epidemics of tobacco and tuberculosis.

Tobacco consumption ranks high among the leading health risks and tuberculosis (TB) is a major public health issue in countries where the smoking problem has reached epidemic proportions. Given that both smoking and TB are major health concerns and are widely prevalent in several countries, it is surprising that the association between smoking and TB is still a matter of debate and controversy. Although several studies have evaluated the effect of smoking on TB, the association has been largely overlooked by the TB and public health communities at large. Three recent reviews, including two meta-analyses, have summarized a large body of published literature on the association between smoking and various TB outcomes. These reviews show that there is considerable evidence that tobacco smoking is associated with TB. The evidence is strong for TB disease but less strong for TB infection and mortality. Even if the effect is relatively modest, the population-attributable risk is likely to be substantial due to the widespread nature of tobacco exposure. TB control programs must begin to address tobacco control as a potential preventive intervention. Since tobacco control will have multiple health benefits, it is likely to be a highly cost-effective intervention from a societal perspective.

Study of thiobarbituric reactive substances and total reduced glutathione as indices of oxidative stress in chronic smokers with and without chronic obstructive pulmonary disease.

BACKGROUND: The imbalance between oxidants and antioxidants is thought to play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). METHODS: Biomarkers of lipid oxidation such as thiobarbituric reactive substances (TBARs), total reduced glutathione (GSH) were estimated in chronic smokers with and without COPD, and non-smokers. RESULTS: The following subjects (all males) were studied: (i) chronic smokers (32.5 +/- 8.6 pack years) with stable COPD (n = 20; mean age 47.2 +/- 7.8 years); (ii) chronic smokers (6.3 +/- 1.9 pack years) without COPD (n = 20; mean age 35.3 +/- 4.5 years); and (iii) non-smokers (n = 20; mean age 37.5 +/- 5.5 years). The mean TBARs levels (nmol of malondialdehyde per ml of plasma) were higher among smokers with COPD (5.72 +/- 1.02) when compared with smokers without COPD (4.85 +/- 0.97) and non-smokers (2.58 +/- 0.56) (p < 0.001). The mean GSH levels (micromol/mg of protein) were significantly higher in non-smokers (0.163 +/- 0.113) compared to smokers with COPD (0.083 +/- 0.05) and those without COPD (0.050 +/- 0.051) (p < 0.001). There was no statistically significant difference in the plasma GSH levels among smokers with and without COPD (p > 0.05). CONCLUSIONS: Our observations demonstrate increased lipid peroxidation because of oxidative stress due to smoking.