Comparative Analysis of Stereotactic Radiation Therapy and Conventional Radiation Therapy in Cancer Pain Control: A Systematic Review and Meta-Analysis.

AIMS: Approximately 55% of patients diagnosed with primary or metastatic cancer endure pain directly attributable to the disease. Consequently, it becomes imperative to address pain management through a comparative analysis of stereotactic radiotherapy (SRT) and conventional radiation therapy (CRT), especially in light of the less efficacious improvement achieved solely through pharmacological interventions. MATERIALS AND METHODS: A systematic exploration was undertaken on PubMed, the Cochrane Library, and Elsevier's ScienceDirect databases to identify studies that compare Stereotactic Radiotherapy to Conventional radiation therapy for pain management in individuals with metastatic bone cancer. The analyses were executed utilizing the random-effects model. RESULTS: A cohort of 1152 participants with metastatic bone cancer was analyzed, demonstrating significantly higher complete pain relief in the Stereotactic Radiotherapy group during both early and late follow-up (RR: 1.61; 95% CI: 1.17, 2.23, p-value: 0.004; I2: 0%). Stereotactic Radiotherapy also showed a non-significant increase in the incidence of partial pain relief (RR: 1.07; 95% CI: 0.85, 1.34, p-value: 0.56; I2: 18%). Furthermore, Stereotactic Radiotherapy was associated with a significantly reduced risk of stationary pain throughout follow-up (RR: 0.61; 95%CI: 0.48, 0.76, p-value: <0.0001; I2: 0. The incidence of progressive pain was non-significantly reduced with Stereotactic Radiotherapy during both early and late follow-up (RR: 0.77; 95% CI: 0.50, 1.17, p-value: 0.22; I2: 0%). Secondary outcomes exhibited a non-significant trend favoring Stereotactic Radiotherapy for dysphagia, esophagitis, pain, and radiodermatitis, while a non-significant increase was observed for nausea, fatigue, and vertebral compression fracture. CONCLUSION: In summary, stereotactic radiation therapy (SRT) has improved in achieving complete pain relief while exhibiting a decreased probability of delivering stationary pain compared to conventional radiation therapy (CRT). Nevertheless, it is crucial in future research to address a noteworthy limitation, specifically, the risk of vertebral compression fracture.

Ethnicity in polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is the commonest gynecological endocrinopathy. Little is known about the exact etiopathogenesis and cardiometabolic mortality and morbidity in women with PCOS. PCOS is beyond the cosmetic concerns of an adolescent and fertility concerns of an adult and can cause serious unhealthy consequences in perimenopausal and postmenopausal age. This area needs to be assessed and addressed since the majority of these patients are lost to follow-up after completion of their families. Good evidence suggests that there are significant racial and ethnic differences in prevalence, insulin resistance, metabolic syndrome, hyperandrogenemia and the related cardiometabolic risk in women with PCOS.

Hepcidin-to-ferritin ratio: A potential novel index to predict iron overload-liver fibrosis in ß-thalassemia major.

OBJECTIVES: We aimed to determine a threshold cutoff for hepcidin, ferritin, and the hepcidin-to-ferritin ratio in the diagnosis of liver fibrosis caused by iron overload in chronic hepatitis C virus (HCV)-free ß-thalassemia major patients . METHODS: This 1:1-matched case-control study included 102 individuals (3-30 yr.); 51 ß-thalassemia major patients with iron overload , and 51 apparently healthy individuals. RESULTS: The highest areas under the receiver operating characteristic curves (AUC-ROCs) for the diagnosis of patients vs. controls had overlapping 95% confidence intervals (CIs): serum hepcidin (0.758; 0.64-0.87; P Ë‚ 0.001), serum ferritin (1.000; 1.00-1.00; P˂0.001), and the hepcidin/ferritin ratio (1.000; 1.00-1.00; P˂0.001). For differentiation of patients with liver fibrosis stages of F0-F1 vs. F2-F4 and F0-F1 vs. F3-F4, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) with P-values˂0.001 were the only statistically significant parameters, while the AUC-ROCs of the hepcidin/ferritin ratio (0.631, P=0.188 and 0.684, P=0.098) exhibited 90% and 89.5% sensitivity, respectively, in staging liver fibrosis. CONCLUSION: Our results showed that the hepcidin/ferritin ratio is as effective as the APRI and maybe a better predictor for the diagnosis of liver fibrosis and discriminating its stages, with excellent sensitivity and specificity compared to its components.

Maintenance of photosynthesis and the antioxidant defence systems have key roles for survival of Halopeplis perfoliata (Amaranthaceae) in a saline environment.

Coastal salt marsh plants employ various combinations of morphological and physiological adaptations to survive under saline conditions. Little information is available on salinity tolerance mechanisms of Halopeplis perfoliata, a C3 stem succulent halophyte. We investigated the growth, photosynthesis and antioxidant defence mechanisms of H. perfoliata under saline conditions (0, 150, 300 and 600 mM NaCl) in an open greenhouse. Optimal shoot succulence, projected shoot area and relative growth rate were obtained in the low (150 mm NaCl) salinity treatment, while growth was inhibited at the highest salinity (600 mm NaCl). The CO2 compensation point and carbon isotope composition of biomass confirmed C3 photosynthesis. Increases in salinity did not affect the photosynthetic pigment content or maximum quantum efficiency of PSII of H. perfoliata. Assimilation of CO2 (A) also remained unaffected by salinity. A modest effect on some gas exchange and photochemistry parameters was observed at 600 mm NaCl. With increasing salinity, there was a continual increase in respiration, suggesting utilisation of energy to cope with saline conditions. Under 300 and 600 mm NaCl, there was an increase in H2 O2 and MDA with a concomitant rise in AsA, GR content and CAT activity. Hence, H. perfoliata appears to be an obligate halophyte that can grow up to seawater salinities by modulating photosynthetic gas exchange, photochemistry and the antioxidant defence systems.

The futile case of the aging ovary: is it mission impossible? A focused review.

Despite immense and impressive progress in the field of reproductive medicine, little has been achieved in terms of replenishing aged ovaries and improving their reproductive outcome. Age causes irreversible damage to human eggs in terms of quantity as well as quality. Nature probably designed women to reproduce best in their twenties and thirties. However, due to social, personal, career, educational and financial pressures, women delay pregnancies until their late thirties, by which time the chance of becoming pregnant is compromised by low fecundity rates and an increased risk of miscarriage. Age, unfortunately, is the most detrimental prognostic factor for success of fertility treatment. We have seen an increasing population of older women seeking fertility treatment. The existing evidence does not offer any clear-cut guidelines for the clinical handling of older women seeking fertility treatment. Various strategies have been tried to improve the fertility outcome of such women, but none has met with significant success. This review focuses on what can and what cannot be done in terms of improving fertility rates in older women.

Detection of Mycobacterium avium subsp. paratuberculosis in bovine faecal samples by Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) TaqMan Assay.

Mycobacterium avium subsp. paratuberculosis, the causative agent of Johne's disease is a degenerative chronic granulomatous disease of bovines. In the present study, quantitative real time polymerase chain reaction (qRT-PCR) using TaqMan chemistry targeting the IS900 sequence of Mycobacterium avium subsp. paratuberculosis (MAP) was employed for the molecular diagnosis of the disease in bovine faecal samples. Out of 200 bovine faecal samples processed, 7 samples were tested as positive by IS900 qRT-PCR. The sensitivity limit of detection of MAP DNA in faecal samples by qRT-PCR TaqMan assay was found to be 0.05pg. No amplification was observed in other Mycobacterial spp. viz. M. phlei, M. smegmatis, M. intracellulare and M. kansasii.

Polycystic ovary syndrome and metabolic syndrome: the worrisome twosome?

By virtue of insulin resistance being the common etiology for polycystic ovary syndrome (PCOS) and metabolic syndrome, the cardiometabolic risks of these two syndromes are shared. The usual concerns of a PCOS patient are cosmetic or reproductive. However, there are more serious concerns past the reproductive age. Early treatment of insulin resistance, hypertension and hyperlipidemia reduces the long-term risk. This review highlights the unhealthy association of metabolic syndrome with PCOS and emphasizes the importance of early diagnosis, patient education and long-term follow-up beyond the reproductive age into menopause to prevent the long-term serious co-morbidities.

Early accumulation of intracellular fibrillar oligomers and late congophilic amyloid angiopathy in mice expressing the Osaka intra-Aß APP mutation.

Pathogenic amyloid-ß peptide precursor (APP) mutations clustered around position 693 of APP-position 22 of the Aß sequence--are commonly associated with congophilic amyloid angiopathy (CAA) and intracerebral hemorrhages. In contrast, the Osaka (E693Δ) intra-Aß APP mutation shows a recessive pattern of inheritance that leads to AD-like dementia despite low brain amyloid on in vivo positron emission tomography imaging. Here, we investigated the effects of the Osaka APP mutation on Aß accumulation and deposition in vivo using a newly generated APP transgenic mouse model (E22ΔAß) expressing the Osaka mutation together with the Swedish (K670N/M671L) double mutation. E22ΔAß mice exhibited reduced α-processing of APP and early accumulation of intraneuronal fibrillar Aß oligomers associated with cognitive deficits. In line with our in vitro findings that recombinant E22Δ-mutated Aß peptides form amyloid fibrils, aged E22ΔAß mice showed extracellular CAA deposits in leptomeningeal cerebellar and cortical vessels. In vitro results from thioflavin T aggregation assays with recombinant Aß peptides revealed a yet unknown antiamyloidogenic property of the E693Δ mutation in the heterozygous state and an inhibitory effect of E22Δ Aß42 on E22Δ Aß40 fibrillogenesis. Moreover, E22Δ Aß42 showed a unique aggregation kinetics lacking exponential fibril growth and poor seeding effects on wild-type Aß aggregation. These results provide a possible explanation for the recessive trait of inheritance of the Osaka APP mutation and the apparent lack of amyloid deposition in E693Δ mutation carriers.

Maslinic acid protects against isoproterenol-induced cardiotoxicity in albino Wistar rats.

The present study aimed to evaluate the protective effect of maslinic acid (MA) on body weight, heart weight, lipids, lipoproteins, lipid peroxidation (LPO), cardiac marker enzymes, and paraoxonase (PON) in normal control and isoproterenol (ISO)-induced myocardial infarcted albino Wistar rats. After treatment with MA (15 mg/kg) for 7 days, myocardial infarction was induced by subcutaneous injection of ISO (85 mg/kg) for two consecutive days. ISO caused a considerable decrease in body weight and increased the heart weight. The concentrations of total cholesterol, triglycerides, very low-density lipoprotein-cholesterol, and low-density lipoprotein-cholesterol were higher, whereas that of high-density lipoprotein-cholesterol was lower, in the serum of ISO-administered rats. The activities of the cardiac marker enzymes creatine kinase, alanine transaminase, aspartate transaminase, and γ-glutamyl transferase and levels of malondialdehyde were elevated in the serum of ISO-treated rats. ISO-administered rats also exhibited a decline in the activity of PON. Pretreatment of rats with MA reduced the effects of ISO on all parameters tested. This is the first report of the protective effect of MA on ISO-induced cardiotoxicity and of an association between PON status and MA supplementation. The observed cardioprotective effects may be due to the antihyperlipidemic potential of MA, inhibition of LPO, and antioxidant activity.

Prediction of mortality 1 year after hospital admission.

OBJECTIVE: Hospital admission, especially for the elderly, can be a seminal event as many patients die within a year. This study reports the prediction of death within a year of admission to hospital of the Simple Clinical Score (SCS) and ECG dispersion mapping (ECG-DM). ECG-DM is a novel technique that analyzes low-amplitude ECG oscillations and reports them as the myocardial micro-alternation index (MMI). METHODS: a convenient sample of 430 acutely ill medical patients (mean age 67.9 ± 16.6 years) was followed up for 1 year after their last admission to hospital. RESULTS: Seventy-four (16.3%) patients died within a year-all but seven had a SCS ≥5 and 40% of those with an MMI ≥50% died. Only six of variables were found by logistic regression to be independent predictors of mortality (i.e. age, MMI, SCS, a discharge diagnosis of cancer, hemoglobin <11 gm% and prior illness that required the patient to spend >50% of daytime in bed). The SCS and MMI plus age were comparable predictors of 1-year mortality: SCS ≥12 predicted 1-year mortality with the highest odds (16.1, chi square 79.09, p < 0.0001) and a score of age plus MMI >104 had an odds ratio of 9.4 (chi square 73.50, p < 0.0001), identified 69% of deaths, and 43% of the 119 patients who exceeded this score were dead within a year. CONCLUSION: SCS and ECG-DM plus age are clinically useful for long-term prognostication. ECG-DM is inexpensive, only takes a few seconds to perform and requires no skill to interpret.

ECG dispersion mapping predicts clinical deterioration, measured by increase in the Simple Clinical Score.

OBJECTIVE: ECG dispersion mapping (ECG-DM) is a novel technique that reports abnormal ECG microalternations. We report the ability of ECG-DM to predict clinical deterioration of acutely ill medical patients, as measured by an increase in the Simple Clinical Score (SCS) the day after admission to hospital. METHODS: 453 acutely ill medical patients (mean age 69.7 +/- 14.0 years) had the SCS recorded and ECGDM performed immediately after admission to hospital. RESULTS: 46 patients had an SCS increase 20.8 +/- 7.6 hours after admission. Abnormal micro-alternations during left ventricular re-polarization had the highest association with SCS increase (p=0.0005). Logistic regression showed that only nursing home residence and abnormal micro-alternations during re-polarization of the left ventricle were independent predictors of SCS increase with an odds ratio of 2.84 and 3.01, respectively. CONCLUSION: ECG-DM changes during left ventricular re-polarization are independent predictors of clinical deterioration the day after hospital admission.

Cardioprotective effect of HPLC standardized ethanolic extract of Terminalia pallida fruits against isoproterenol-induced myocardial infarction in albino rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Terminalia pallida is an evergreen endemic tree, mentioned in Ayurveda as the fruits of Terminalia pallida are excellent in cardioprotective property. Tribal people use Terminalia pallida fruit for the treatment of diabetes and this plant widely used in many other disorders. AIM OF STUDY: The present investigation was to evaluate the antioxidant, biochemical profile and histological studies of qualitatively standardized ethanolic extract of Terminalia pallida fruits (TpFE) against isoproterenol-induced myocardial infarction in rats. MATERIALS AND METHODS: TpFE was standardized by high performance liquid chromatography (HPLC) and mass spectroscopy (MS). Rats were pretreated orally with different doses of TpFE (100, 300, and 500mgkg(-1) body weight) and cardioprotective positive control gallic acid (GA) for 30 days prior to isoproterenol (ISO) induced myocardial infarction. The rats were sacrificed, hearts were collected and homogenized for biochemical analysis. The effects on total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein cholesterol (VLDL-C), high density lipoprotein cholesterol (HDL-C), lipid peroxidation (LPO) marker, malondialdehyde (MDA), creatine kinase (CK), lactate dehydrogenase (LDH), alanine transaminase (ALT), aspartate transaminase (AST), catalase (CAT), glutathione peroxidase (GPx), sodium potassium (Na(+)/K(+)), calcium (Ca(2+)) and magnesium (Mg(2+)) adenosine triphosphatases (ATPases) were estimated in heart tissue homogenate. RESULTS: Rats administered with ISO showed a significant increase in TC, TG, LDL-C, VLDL-C, and MDA and a significant decrease in HDL-C, cardiac marker enzymes - CK, LDH, ALT and AST. ISO significantly reduced antioxidants - CAT, GPx, and membrane bound enzymes - Na(+)/K(+), Ca(2+) and Mg(2+) ATPases. Pretreatment with TpFE (100, 300, and 500mgkg(-1) bw) and GA (15mgkg(-1) bw) for a period of 30 days significantly inhibited the effects of ISO. Moreover, biochemical findings were supported by histopathological observations. CONCLUSION: The present study provide evidence for the first time, that TpFE pretreatment ameliorated myocardial injury in ISO-induced myocardial infarcted rats and exhibited cardioprotective activity.

Color Doppler findings of post-biopsy arteriovenous fistula in renal transplant.

Post biopsy arterio-venous fistula in renal transplant range in incidence from 15-16%. Spontaneous resolution of 75% A-V fistulas is seen within four weeks. We report a patient with post biopsy arterio-venous fistula who had developed unexplained hypertension with no definite feature of rejection on biopsy. Doppler application revealed an arterio-venous fistula which showed spontaneous resolution in six weeks.

Antibacterial activity directed isolation of compounds from Punica granatum.

Chemical investigation of the methanolic extract of pomegranate fruit following antibacterial activity directed isolation led to the isolation of pelargonidin-3-galactose, cyanidin-3-glucose, gallic acid, quercetin, and myricetin. All these compounds exhibited substantial activity against species of corynebacteria, staphylococci, streptococci, Bacillus subtilis, Shigella, Salmonella, Vibrio cholera, and Escherichia coli. However, all these compounds were more active against Gram-positive species. On comparing the activity of all the isolated pure compounds, it was found that gallic acid showed the highest antibacterial activity against all the tested sensitive strains and the activity of the remaining pure compounds was almost same due to the structural similarities of the compounds. The reason for antibacterial activity of all pure compounds was attributed to their phenolic structure.

Mucormycosis in patients with complicated cirrhosis.

INTRODUCTION: Rhino-orbito-cerebral mucormycosis is a rapidly progressive and fatal disease that mostly occurs in patients with diabetes mellitus and immunocompromised status. Antifungal therapy with surgical debridement is the standard of care. Patients with cirrhosis of liver are more prone to develop different infections. Many of these also show glucose intolerance or frank diabetes mellitus. Little is known about the clinical presentation and outcome of mucormycosis in patients with cirrhosis. Treatment is difficult due to underlying coagulopathy and hepatic dysfunction. METHODS: Medical records of the past five years were searched for the cirrhotic patients admitted with associated diagnosis of mucormycosis or fungal infection. Six patients with mucormycosis were identified. RESULTS: Out of six patients, five were male. Age range was 15-57 years. Cause of cirrhosis was hepatitis C in four patients, hepatitis B in one patient and autoimmune hepatitis in one patient. Two patients had hepatocellular carcinoma. Four patients had diabetes mellitus, of which one patient was also on steroids for the autoimmune liver disease. Four patients had spontaneous bacterial peritonitis at the time of admission. All six patients presented with rhino-orbitocerebral mucormycosis with nasal discharge and upper motor neuron signs. Diagnosis of mucormycosis was made by culture of biopsy and scrapings taken from the palate and nasal sinuses. These patients received amphotericin B. Four patients died while in the hospital, while two patients died within next few days after discharge. CONCLUSION: Mucormycosis in cirrhosis is not very common and has a poor prognosis. Patients with advanced cirrhosis and diabetes mellitus are at risk of developing infection.

An evaluation of molecular markers for improved detection of breast cancer metastases in sentinel nodes.

BACKGROUND AND OBJECTIVES: In patients with breast cancer (BC), the sentinel node (SN) is the first node in the axillary basin that receives the primary lymphatic flow and can be used to accurately assess the axillary nodal status without removal of the axillary contents. Currently, histology and/or immunohistochemistry are the routine methods of SN analysis. The primary objective of this study was to develop a reproducible reverse transcription (RT) PCR assay, with emphasis on achieving high specificity for accurate detection of BC micrometastases in the SN. To correct for the heterogeneity of BC cells, a multimarker approach was followed, with the further aim of improving the detection rate of the assay. METHODS: In total, 73 markers were evaluated, of which 7 were breast epithelial markers and 66 were either cancer testis or tumour associated antigens. Twelve BC cell lines and 30 SNs (from 30 patients) were analysed using RT-PCR to determine the in vitro and in vivo detection rates for each of the markers. In addition, 20 axillary nodes obtained from a patient with brain death were used as controls to optimise the PCR cycle numbers for all the markers. RESULTS: Of the 30 SNs, 37% (11/30) were positive on haematoxylin and eosin analysis. Extensive immunohistochemical (IHC) analyses of the haematoxylin and eosin negative nodes confirmed the presence of very small numbers of BC cells in an additional 40% (12/30) of SNs. Molecular analysis with the hMAM-A alone identified metastases in 70% (21/30) of SNs. Using MAGE-A3 in combination with hMAM-A identified metastases in 90% (27/30) of patients. Seven SNs (23%) were negative for micrometastases (with haematoxylin and eosin and IHC) but RT-PCR positive for either hMAM-A or MAGE-A3. CONCLUSIONS: As IHC analysis resulted in a 77% detection rate compared with 37% for haematoxylin and eosin analysis, we consider that IHC is essential in order not to miss SN micrometastases. Molecular analysis with hMAM-A and MAGE-A3 allows detection of BC micrometastases with a 90% detection rate. However, the clinical value of histologically negative but RT-PCR positive SNs can only be determined with long term follow up.

Oral candidal species among smokers and non-smokers.

OBJECTIVE: To determine the various oral Candidal species among healthy Malaysian adults. DESIGN: Case-control study. PLACE AND DURATION OF STUDY: This study was collaborated between the Department of Medical Microbiology, Faculty of Medicine and Department of Oral Pathology, Oral Medicine and Periodontology, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia, between September 2002 till January 2004. PATIENTS AND METHODS: One hundred adults (50 smokers and 50 non-smokers), aged between 40 and 70 years were studied. Swabs and carbohydrate assimilation (Saboraud Dextrose Agar, Corn Meal Agar, API 20C AUX System) were performed. Specimens were collected from dorsum of the tongue, buccal mucosa and commissures (right and left each). Colony forms were established by positive colony forming units, on SDA medium (24-48 hours). Germ tube test for (true/pseudohyphae) growth was done on Corn Meal Agar Medium. Candida biotypes were evaluated by API 20C AUX system, which had a numerical 7 digit profile, added to evaluate a definite Candida species. RESULTS: Thirty-five percent of Malaysian adults harbored Candida intraorally. Candidal species identified among 100 subjects had C. albicans (27) 77%, C. glabrata (3) 8%, C. famata, C. tropicalis, C. krusei, C. lusitaniae and C. guilliermondii (1) 3% each. Thirty-three positive cases comprised of 35 species i.e. two cases had two species each. Fifty seven percent of these were smokers and 43% non-smokers. These included 40% Chinese, 36% Malays and 24% Indians. Species were, however, not specified according to intra-oral sites i.e. buccal, commissural mucosa and dorsum of tongue. CONCLUSION: On this series C. albicans is the most common species found in the oral cavity of Malaysian adults. It is equally frequent in smokers and non-smokers, but showed a predilection for the ethnic Chinese group.

Source identification of Indian opium based on chromatographic fingerprinting of amino acids.

Total and free pool of amino acids was determined in Indian opium samples using liquid chromatography (LC) with post-column opthalaldehyde derivatization followed by its fluorimetric detection. The limit of detection (LOD) was found to be in the range of 2-10 pmol with a signal to noise ratio of 3:1 and limit of quantitation (LOQ) was found to be in the range of 7-31 pmol with a signal to noise ratio of 10:1. The recovery of amino acids was found to be in the range of 86-103%. A total of 124 Indian opium samples were collected from the states of Madhya Pradesh (MP), Uttar Pradesh (UP) and Rajasthan (Raj), covering 14 licit opium growing divisions of India were chromatographically fingerprinted for the presence of various amino acids. The amino acids identified in sample hydrosylate included D, T, S, S, G, A, V, I, L, Y, F, H, K and R, while the analysis of free pool of amino acids (80% aqueous ethanol extract) indicated the presence of D, T, S, E, A, V, I, L, Y, H, K respectively. Multiple discriminant analysis was applied to the quantitative total amino acid data to determine an optimal classifier in order to evaluate the source of Indian opium. The foremost amino acid variables that accounted for the true discrimination were identified as D, E, G, A, F and K in evaluating the geographical origin of Indian opium and the predictive value based on the discriminant analysis was found to be 90% in relation to the source of opium samples. Chemometrics performed with amino acid analytical data was used successfully in discriminating the licit opium growing divisions of India into three major groups, viz. groups I, II and III. The methodology developed may find wide application in forensic analysis.

Production, purification and some properties of Bac201, a bacteriocin-like inhibitory substance produced by Staphylococcus aureus AB201.

Staphylococcus aureus AB201, a clinical isolate from wound pus, produced a bacteriocin-like inhibitory substance termed as Bac201, that was inhibitory to Streptococcus agalactiae, Enterococcus faecalis, Acinetobacter calcoaceticus, Neisseria meningitidis and a number of staphylococcal species. It was purified to homogeneity by ammonium sulfate precipitation, gel filtration (BioSil-SEC-125), and reversed-phase high performance liquid chromatography (Vydac C4). The native Bac201 was sized at approximately 170-kDa as determined by GF HPLC. Fraction-I (native Bac201), having antibacterial activity was also examined by transmission electron microscopy and appeared as globular structure showing resemblance with phage-like objects. The purification of Bac201 resulted in 466-fold increase in specific activity and recovery of 0.94% of total antibacterial activity. The purified Bac201 migrated as single band on SDS-PAGE with an estimated molecular mass of about 41-kDa. Bac201 was sensitive to proteolytic enzymes, resistant to heat and organic solvents, and active over a wide range of pH (2.5-10). The amino acid composition revealed a general resemblance with other reported high molecular mass bacteriocins and predominance of glycine (39%), proline (13%) and alanine (8%) residues. Further results showed that Bac201 has a bactericidal effect on sensitive cells which is not produced by either cell lysis or apparent loss of membrane permeability.