Visual patterns of breast attenuation artifacts in women and men with an upright and supine cadmiun-zinc-telluride camera.

BACKGROUND: Breast attenuation artifacts occurring with upright cadmium-zinc-telluride (CZT) cardiac imaging systems have not been well characterized. METHODS: 216 consecutive patients with Single Photon Emission Computerized Tomography myocardial perfusion imaging and no angiographically significant obstructive coronary artery disease were identified. All upright and supine SPECT images as well as coronary angiograms were reviewed and analyzed in blinded fashion. RESULTS: In women imaged upright, more visual false positive defects were noted in the inferior wall compared to the anterior wall (26 vs. 10 at rest, p = 0.006, and 33 vs. 13 at stress, p < 0.001). Visual inferior wall defects were more common in the upright than supine position at stress (33 vs. 23, p = 0.018) and rest (26 vs. 14, p = 0.011), and most apparent in non-obese women (13 vs. 8, at stress, p = 0.059 and 11 vs. 5, at rest, p = 0.014). CONCLUSIONS: With upright CZT myocardial perfusion imaging, women often have visible inferior wall attenuation artifact defects, likely from pendant breast tissue. These inferior wall attenuation artifacts may be seen in non-obese female patients.

Effects of gender and defect reversibility on detection of coronary disease with an upright and supine cadmium-zinc-telluride camera.

BACKGROUND: Limited data address the roles of gender, perfusion defect reversibility, and imaging position in interpretation of images acquired on an upright/supine cadmium-zinc-telluride (CZT) cardiac imaging system. METHODS AND RESULTS: From a consecutive cohort of patients imaged on an upright/supine CZT camera, 260 patients with coronary angiograms were studied. Multivariable models identified gender as a significant effect modifier for imaging variables of CAD. For males, a supine summed stress score (SSS) ≥ 3 provided high accuracy (sensitivity 70.7%, specificity 72.2%), and highest contribution to multivariable models. In females, supine SSS ≥ 2 provided the best cut-off for defect size and severity (sensitivity 90%, specificity 35.9%), but specificity was improved substantially to 53.3% with decrease in sensitivity to 80% by also requiring quantitative identification of perfusion defect reversibility in the supine position. Eight variables, accurate for predicting coronary disease, were more accurate with supine than upright imaging. CONCLUSIONS: Perfusion defect reversibility improved specificity in female patients for detection of coronary disease compared to perfusion defect size and extent alone. Supine images provided superior accuracy for detection of coronary disease compared to upright images.

Synthesis of Novel N-Acylhydrazones and Their C-N/N-N Bond Conformational Characterization by NMR Spectroscopy.

In this article, a synthesis of N'-(benzylidene)-2-(6-methyl-1H-pyrazolo[3,4-b]quinolin-1-yl)acetohydrazides and their structural interpretation by NMR experiments is described in an attempt to explain the duplication of some peaks in their 1H- and 13C-NMR spectra. Twenty new 6-methyl-1H-pyrazolo[3,4-b]quinoline substituted N-acylhydrazones 6(a-t) were synthesized from 2-chloro-6-methylquinoline-3-carbaldehyde (1) in four steps. 2-Chloro-6-methylquinoline-3-carbaldehyde (1) afforded 6-methyl-1H-pyrazolo[3,4-b]quinoline (2), which upon N-alkylation yielded 2-(6-methyl-1H-pyrazolo[3,4-b]quinolin-1-yl)acetate (3). The hydrazinolysis of 3 followed by the condensation of resulting 2-(6-methyl-1H-pyrazolo[3,4-b]quinolin-1-yl)acetohydrazide (4) with aromatic aldehydes gave N-acylhydrazones 6(a-t). Structures of the synthesized compounds were established by readily available techniques such as FT-IR, NMR and mass spectral studies. The stereochemical behavior of 6(a-t) was studied in dimethyl sulfoxide-d6 solvent by means of 1H NMR and 13C NMR techniques at room temperature. NMR spectra revealed the presence of N'-(benzylidene)-2-(6-methyl-1H-pyrazolo[3,4-b]quinolin-1-yl)acetohydrazides as a mixture of two conformers, i.e., E(C=N)(N-N) synperiplanar and E(C=N)(N-N)antiperiplanar at room temperature in DMSO-d6. The ratio of both conformers was also calculated and E(C=N) (N-N) syn-periplanar conformer was established to be in higher percentage in equilibrium with the E(C=N) (N-N)anti-periplanar form.

Microwave-Assisted Synthesis of (Piperidin-1-yl)quinolin-3-yl)methylene)hydrazinecarbothioamides as Potent Inhibitors of Cholinesterases: A Biochemical and In Silico Approach.

Alzheimer's disease (AD), a progressive neurodegenerative disorder, characterized by central cognitive dysfunction, memory loss, and intellectual decline poses a major public health problem affecting millions of people around the globe. Despite several clinically approved drugs and development of anti-Alzheimer's heterocyclic structural leads, the treatment of AD requires safer hybrid therapeutics with characteristic structural and biochemical properties. In this endeavor, we herein report a microwave-assisted synthesis of a library of quinoline thiosemicarbazones endowed with a piperidine moiety, achieved via the condensation of 6/8-methyl-2-(piperidin-1-yl)quinoline-3-carbaldehydes and (un)substituted thiosemicarbazides. The target N-heterocyclic products were isolated in excellent yields. The structures of all the synthesized compounds were fully established using readily available spectroscopic techniques (FTIR, 1H- and 13C-NMR). Anti-Alzheimer potential of the synthesized heterocyclic compounds was evaluated using acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. The in vitro biochemical assay results revealed several compounds as potent inhibitors of both enzymes. Among them, five compounds exhibited IC50 values less than 20 µM. N-(3-chlorophenyl)-2-((8-methyl-2-(piperidin-1-yl)quinolin-3-yl)methylene)hydrazine carbothioamide emerged as the most potent dual inhibitor of AChE and BChE with IC50 values of 9.68 and 11.59 µM, respectively. Various informative structure-activity relationship (SAR) analyses were also concluded indicating the critical role of substitution pattern on the inhibitory efficacy of the tested derivatives. In vitro results were further validated through molecular docking analysis where interactive behavior of the potent inhibitors within the active pocket of enzymes was established. Quinoline thiosemicarbazones were also tested for their cytotoxicity using MTT assay against HepG2 cells. Among the 26 novel compounds, there were five cytotoxical and 18 showed proliferative properties.

Crimean-Congo Hemorrhagic Fever Virus in Humans and Livestock, Pakistan, 2015-2017.

We detected Crimean-Congo hemorrhagic fever virus infections in 4 provinces of Pakistan during 2017-2018. Overall, seroprevalence was 2.7% in humans and 36.2% in domestic livestock. Antibody prevalence in humans was highest in rural areas, where increased contact with animals is likely.

Serologic Evidence of Severe Fever with Thrombocytopenia Syndrome Virus and Related Viruses in Pakistan.

We describe the seroprevalence of severe fever with thrombocytopenia syndrome virus (SFTSV) and the association of antibody occurrence with location, sex, and age among the human population in Pakistan. Our results indicate substantial activity of SFTSV and SFTSV-related viruses in this country.

Dissecting microbial community structure in sewage treatment plant for pathogens' detection using metagenomic sequencing technology.

Continuous observation of wastewater treatment plants is very crucial to keep them safe for proper use and protection from pathogenic contamination. Illumina sequencing technology was used for microbiome structuring from various samples taken from different portions of the wastewater treatment plant, including influent, activated, return sludge and effluent, where different microbial compositions were found. The effluent section was found to have pathogenic microbes such as viruses, Alpha- and deltaproteobacteria, Actinobacteria, Bacteroidetes, clostridia, and bacilli in various concentrations. The presence of viruses, Mycobacterium sp., Mycobacterium fortuitum, bacteroidia, and bacilli was investigated. The species Mycobacterium was found to be higher in quantity in the effluent section. Viruses, including hepatitis A and E, were detected in higher quantity in the effluent part of the sludge in comparison with the influent part of the plant. Our discovery reveals the significance and observation of wastewater treatment plants for the existence of water-borne pathogens in the effluent, principally due to the effect on humans while reusing the water.

High yield expression, characterization, and biological activity of IFNα2-Tα1 fusion protein.

The use of interferon α-2 in combination with thymosin α-1 shows higher anti-cancer effect in comparison when both are used individually because of their synergistic effects. In this study we produced an important human interferon α-2-thymosin α-1 (IFNα2-Tα1) fusion protein with probable pharmaceutical properties coupled to its high-level expression, characterization, and study of its biological activity. The IFNα2-Tα1 fusion gene was constructed by over-lap extension PCR and expressed in Escherichia coli expression system. The expression of IFNα2-Tα1 fusion protein was optimized to higher level and its maximum expression was obtained in modified terrific broth medium when lactose was used as inducer. The fusion protein was refolded into its native biologically active form with maximum yield of 83.14% followed by purification with ∼98% purity and 69% final yield. A band of purified IFNα2-Tα1 fusion protein equal to ∼23 kDa was observed on 12 % SDS-PAGE gel. The integrity of IFNα2-Tα1 fusion protein was confirmed by western blot analysis and secondary structure was assessed by CD spectroscopy. When IFNα2-Tα1 fusion protein was subjected to its biological activity analysis it was observed that it exhibits both IFNα2 & Tα1 activities as well as significantly higher anticancer activity as compared to IFNα-2 alone.

Rapid Identification of Clinically Relevant Mycobacterium Species by Multicolor Melting Curve Analysis.

The sustained increase in the incidence of nontuberculous mycobacterial (NTM) infection and the difficulty in distinguishing these infections from tuberculosis constitute an urgent need for NTM species-level identification. The MeltPro Myco assay is the first diagnostic system that identifies 19 clinically relevant mycobacteria in a single reaction based on multicolor melting curve analysis run on a real-time PCR platform. The assay was comprehensively evaluated regarding its analytical and clinical performances. The MeltPro Myco assay accurately identified 51 reference mycobacterial strains to the species/genus level and showed no cross-reactivity with 16 nonmycobacterial strains. The limit of detection was 300 bacilli/ml, and 1% of the minor species was detected in the case of mixed infections. Clinical studies using 1,163 isolates collected from five geographically distinct health care units showed that the MeltPro Myco assay correctly identified 1,159 (99.7%) samples. Further testing with 94 smear-positive sputum samples showed that all samples were correctly identified. Additionally, the entire assay can be performed within 3 h. The results of this study confirmed the efficacy of this assay in the reliable identification of mycobacteria, suggesting that it might potentially be used as a screening tool in regions endemic for tuberculosis.

Modulative effect of a new hydrazide derivative on wheat-induced pulmonary inflammation in rats.

NEW FINDINGS: What is the central question of this study? What is the mechanism of wheat-induced pulmonary inflammation and how does a hydrazide derivative modulate it? What is the main finding and its importance? A hydrazide derivative significantly reduced wheat-induced pulmonary inflammation in a rat model mainly by down-regulating inflammatory cell infiltration, pathological lesions in the lungs and the level of pro-inflammatory cytokines, COX-1, COX-2 and T-cell proliferation. ABSTRACT: We investigated the ameliorative anti-inflammatory effect of a previously synthesized hydrazide derivative (N'-(4-methoxybenzylidene)-6-(4-chlorophenyl)-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridine-4-carbohydrazide; MD) as an immunomodulator in a newly developed allergen-induced pulmonary inflammation (AIPI) rat model. Wheat and thresher dust were used as allergens to induce pulmonary inflammation while MD was used to reverse the inflammatory response. Blood and bronchoalveolar lavage fluid (BALF) were collected after killing the rats and inflammatory cells were counted. Histological analysis of lung airways was carried out by haematoxylin and eosin and periodic acid-Schiff staining while the level of total serum IgE, interleukin (IL)-4, IL-5 and cyclooxygenase (COX)-1 in BALF and in vitro T-cell proliferation in spleen were measured through enzyme-linked immunosorbent assay. mRNA expression level of IL-4, IL-5, IL-13, transforming growth factor ß (TGF-ß), interferon-γ, tumour necrosis factor α, COX-1 and COX-2 was evaluated by qRT-PCR. A liver and kidney function test was used to observe any toxic impact of MD. The results indicated that 2 mg of wheat and thresher dust led to higher levels of inflammatory cytokines in the blood, BALF and lung airways of rats. MD potentially down-regulated the inflammatory cell infiltration in BALF and pathological lesions in the lung airways of AIPI rats. MD significantly suppressed the elevated total serum IgE, along with IL-4, IL-5, IL-13, TGF-ß, COX-1 and COX-2 mRNA expression and T-cell proliferation in spleen. In conclusion, MD at 10 mg kg-1 exhibited a significant reduction in all the markers in both wheat- and thresher dust-induced pulmonary inflammation mainly by inhibiting pro-inflammatory cytokine production and T-cell proliferation. The data suggest that inhibition of the T-cell response may be responsible for the modulative effect of MD in an AIPI rat model.

Acquired Von Willebrand Syndrome (AVWS) in cardiovascular disease: a state of the art review for clinicians.

Von Willebrand Factor (vWF) is a large glycoprotein with a broad range of physiological and pathological functions in health and disease. While vWF is critical for normal hemostasis, vascular integrity and repair, quantitative and qualitative abnormalities in the molecule can predispose to serious bleeding and thrombosis. The heritable form of von Willebrand Disease was first described nearly a century ago, but more recently, recognition of an acquired condition known as acquired von Willebrand Syndrome (AVWF) has emerged in persons with hematological, endocrine and cardiovascular diseases, disorders and conditions. An in-depth understanding of the causes, diagnostic approach and management of AVWS is important for practicing clinicians.

Stability Indicating UHPLC-PDA Assay for Simultaneous Determination of Antazoline Hydrochloride and Naphazoline Hydrochloride in Ophthalmic Formulations.

In the present study, a newly developed method based on ultrahigh performance liquid chromatography (UHPLC) was optimized for the simultaneous determination of antazoline hydrochloride (ANZ) and naphazoline hydrochloride (NFZ) in ophthalmic formulations. Isocratic separation of ANZ and NFZ was performed at 40 °C with an ACE Excel 2 C18-PFP column (2 µm, 2.1 × 100 mm) at a flow rate of 0.6 mL min-1 whereas the mobile phase consisted of acetonitrile/phosphate buffer (60:40, v/v, pH 3.0) containing 0.5% triethylamine. Both analytes were detected at a wavelength of 285 nm and the injection volume was 1.0 µL. The overall run time per sample was 4.5 min with retention time of 0.92 and 1.86 min for NFZ and ANZ, respectively. The calibration curve was linear from 0.500-100 µg mL-1 for ANZ and NFZ with a correlation coefficient ≥ 0.9981 while repeatability and reproducibility (expressed as relative standard deviation) were lower than 1.28 and 2.14%, respectively. In comparison with high-performance liquid chromatography (HPLC), the developed UHPLC method had remarkable advantages over HPLC as the run time was significantly reduced by 3.4-fold with a 5-fold decreased solvent consumption. Forced degradation studies indicated a complete separation of the analytes in the presence of their degradation products providing high degree of method specificity. The proposed UHPLC method was demonstrated to be simple and rapid for the determination of ANZ and NFZ in commercially available ophthalmic formulations providing recoveries between 99.6 and 100.4%.

Detection of Anti-Hepatitis B Virus Drug Resistance Mutations Based on Multicolor Melting Curve Analysis.

Detection of anti-hepatitis B virus (HBV) drug resistance mutations is critical for therapeutic decisions for chronic hepatitis B virus infection. We describe a real-time PCR-based assay using multicolor melting curve analysis (MMCA) that could accurately detect 24 HBV nucleotide mutations at 10 amino acid positions in the reverse transcriptase region of the HBV polymerase gene. The two-reaction assay had a limit of detection of 5 copies per reaction and could detect a minor mutant population (5% of the total population) with the reverse transcriptase M204V amino acid mutation in the presence of the major wild-type population when the overall concentration was 104 copies/µl. The assay could be finished within 3 h, and the cost of materials for each sample was less than $10. Clinical validation studies using three groups of samples from both nucleos(t)ide analog-treated and -untreated patients showed that the results for 99.3% (840/846) of the samples and 99.9% (8,454/8,460) of the amino acids were concordant with those of Sanger sequencing of the PCR amplicon from the HBV reverse transcriptase region (PCR Sanger sequencing). HBV DNA in six samples with mixed infections consisting of minor mutant subpopulations was undetected by the PCR Sanger sequencing method but was detected by MMCA, and the results were confirmed by coamplification at a lower denaturation temperature-PCR Sanger sequencing. Among the treated patients, 48.6% (103/212) harbored viruses that displayed lamivudine monoresistance, adefovir monoresistance, entecavir resistance, or lamivudine and adefovir resistance. Among the untreated patients, the Chinese group had more mutation-containing samples than did the Pakistani group (3.3% versus 0.56%). Because of its accuracy, rapidness, wide-range coverage, and cost-effectiveness, the real-time PCR assay could be a robust tool for the detection if anti-HBV drug resistance mutations in resource-limited countries.

Risk management and loss prevention strategies for fertilizer industries.

Various toxic and flammable gases exist in the fertilizer industry whose release quantification is very important regarding emergency preparedness, planning and response, and well-being of the community. ALOHA threat zones and threat at a point coupled with MARPLOT are evaluated for ammonia, methane, carbon dioxide and hydrogen release, and outdoor and indoor concentrations of these gases in nearby residences and highways calculated. These footprints are calculated using ALOHA which requires inputs such as site data, site location, building type, gas name, atmospheric inputs, release source information and dispersion model to display the threat zone, which can then be shown on MARPLOT. Potential impact of these releases on the community is mitigated through releasing equipment isolations, water sprays for dilutions, dilutions through steam or air and emergency sirens for information. This article covers hazards in the fertilizer industry, and provides general guidelines for operational staff of any industry to mitigate hazards.

Genotypic analysis of hepatitis E virus (HEV) from sporadic symptomatic cases in Pakistan.

Pakistan is the fifth most populous nation in the world and faces several challenges, including devastating floods, sub-optimal sanitary conditions, clustered accommodations, and unregulated cross-border movements. These drastic population shifts make it vulnerable to the efficient spread of the Hepatitis E virus (HEV). The current study analyzed the genotypic characteristics and variants of the Hepatitis E virus circulating in the population of Pakistan. A total of 75 ELISA-IgM positive samples were collected from three metropolitan cities: Lahore, Peshawar, and Karachi, and subjected to viral RNA extraction. The amplification of the HEV RNA-dependent RNA polymerase (RdRp) region was done using Nested PCR and degenerate primers. Out of the total, 40% of the samples were positive for HEV RNA. Sequencing and phylogenetic analysis identified the new HEV isolates as Subtype 1 g, a subtype within an existing HEV genotype 1. This shift warrants investigation into its impact on clinical manifestation and disease severity. Importantly, this study marks the first HEV subtype analysis in Pakistan, contributing valuable insights into subtype diversity and prevalence in the region.

Risk of infection with arboviruses in a healthy population in Pakistan based on seroprevalence.

Infectious diseases caused by arboviruses are a public health concern in Pakistan. However, studies on data prevalence and threats posed by arboviruses are limited. This study investigated the seroprevalence of arboviruses in a healthy population in Pakistan, including severe fever with thrombocytopenia syndrome virus (SFTSV), Crimean-Congo hemorrhagic fever virus (CCHFV), Tamdy virus (TAMV), and Karshi virus (KSIV) based on a newly established luciferase immunoprecipitation system (LIPS) assays, and Zika virus (ZIKV) by enzyme-linked immunosorbent assays (ELISA). Neutralizing activities against these arboviruses were further examined from the antibody positive samples. The results showed that the seroprevalence of SFTSV, CCHFV, TAMV, KSIV, and ZIKV was 17.37%, 7.58%, 4.41%, 1.10%, and 6.48%, respectively, and neutralizing to SFTSV (1.79%), CCHFV (2.62%), and ZIKV (0.69%) were identified, as well as to the SFTSV-related Guertu virus (GTV, 0.83%). Risk factors associated with the incidence of exposure and levels of antibody response were analyzed. Moreover, co-exposure to different arboviruses was demonstrated, as thirty-seven individuals were having antibodies against multiple viruses and thirteen showed neutralizing activity. Males, individuals aged ≤40 years, and outdoor workers had a high risk of exposure to arboviruses. All these results reveal the substantial risks of infection with arboviruses in Pakistan, and indicate the threat from co-exposure to multiple arboviruses. The findings raise the need for further epidemiologic investigation in expanded regions and populations and the necessity to improve health surveillance in Pakistan.

Phytochemical, toxicological and antimicrobial evaluation of Lawsonia inermis extracts against clinical isolates of pathogenic bacteria.

BACKGROUND: The emerging resistance of pathogen against the currently available antimicrobial agents demands the search of new antimicrobial agents. The use of medicinal plants as natural substitute is the paramount area of research to overwhelm the drug resistance of infectious agents. Scientists have not made enough effort on the evaluation of safety of medicinal plant yet. METHODS: In the present study antimicrobial activity of Lawsonia inermis is investigated against clinical isolates of seven bacteria including four Gram negative (Escherichia coli, Salmonella typhi, Klebsiella spp., Shigella sonnei) and three Gram positive (Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis) using disc diffusion method. Four types of Lawsonia inermis extracts were prepared using methanol, chloroform, acetone and water as extraction solvents, while DMSO (Dimethyl sulfoxide) and water as dissolution solvents. The rate and extent of bacterial killing was estimated by time-kill kinetic assay at 1× MIC of each bacterial isolate. The overall safety of Lawsonia inermis extracts was assessed in mice. RESULTS: Lawsonia inermis displayed noteworthy antimicrobial activity against both gram positive and gram negative bacterial strains used in the study. The minimum value of MIC for different bacterial strains ranged from 2.31 mg/ml to 9.27 mg/ml. At 1x MIC of each bacterial isolate, 3log10 decrease in CFU was recorded after 6 hours of drug exposure and no growth was observed in almost all tested bacteria after 24 hours of exposure. No sign of toxidrome were observed during in vivo toxicity evaluation in mice at 300 mg/kg concentration. CONCLUSION: In conclusion, the present study provides the scientific rational for medicinal use of Lawsonia inermis. The use of Lawsonia inermis extracts is of great significance as substitute antimicrobial agent in therapeutics.

Determination of affected brain regions at various stages of Alzheimer's disease.

The objective of study was to explore those brain areas that were affected at each stage during the progression of Alzheimer's disease (AD). Six affected brain areas were explored at mild cognitive impairment, four at first stage and six at each of second and third stage of Alzheimer's disease. The common brain regions among these stages were cuneus, precuneus, calcarine cortex, middle frontal gyrus, superior frontal gyrus, and frontal superior medial gyrus. The fMRI data at the resting state of 18 AD patients who were converted from MCI to stage 3 of Alzheimer's were taken from ADNI public source database. Among these patients, there were ten males and eight females. Independent component analysis was used to explore affected brain regions and an algorithm based on deep learning convolutional neural network was proposed for binary classification among the stages of Alzheimer's disease. The proposed CNN model delivered 94.6 % accuracy for separating stage 1 of Alzheimer's disease from mild cognitive impairment. 96.7 % accuracy was acquired to distinguish stage 2 of Alzheimer's disease from mild cognitive impairment, and stage 3 of Alzheimer's disease was separated from mild cognitive impairment with an accuracy of 97.8 %.

Behavior-based safety program for process industries.

Objectives. This article describes the reduction of unsafe behaviors observed at a fertilizer complex by implementation of a behavior-based safety (BBS) program via a behavior observation form developed by a multidisciplinary team. Methods. Six observation categories, i.e., position of people, reaction of people, personal protective equipment (PPE), tools used, operating procedures and housekeeping, are used to monitor safe and unsafe behaviors for a period of 18 months. Results. Safe behaviors increased from 57 to 70% and unsafe behaviors reduced from 40 to 26%. Behaviors of employees working in various sections of fertilizer complex such as ammonia, urea, utility, bagging/shipping and workshop were also observed. Non-compliance with PPE, housekeeping and standard operating procedures was also monitored in individual sections. Non-operational areas including the administration block, housing colony, maintenance workshop, warehouse, fire station and electrical substation were also observed. Among these, the maximum unsafe behaviors are for the housing colony and minimum for the electrical substation. Conclusion. It has been concluded that working on the housing colony, administration block and fire station areas will address 74% unsafe behaviors of non-operational areas. For practical applications, worldwide industries can implement this BBS program to enhance BBS, thus reducing unsafe behaviors and increasing employee morale.

Identification and purification of antigenic 34 kDa outer membrane protein of Salmonella typhi.

BACKGROUND: Salmonella Typhi is a pathogenic bacterium that causes a number of infectious diseases such as gastroenteritis and typhoid fever. In this study, an antigenic (34 kDa) protein was identified, purified, and characterized from outer membrane of Salmonella typhi. METHODS: Immunoblot analysis was used to screen antigenic proteins from outer membrane of Salmonella Typhi. Proteins from outer membrane were isolated and resolved on SDS-PAGE. In immunoblot analysis, four proteins with the following molecular weights of 60 kDa, 54 kDa, 34 kDa, and 26 kDa were identified as highly antigenic against the serum of patients suffering from typhoid fever. One of these outer membrane proteins, with a molecular mass of 34 kDa, was selected for this study. The 34 kDa protein was purified and characterized by a combination of anion exchange chromatography and gel permeation chromatography. The molecular weight of 34 kDa was determined using SDS-PAGE electrophoresis. The antigenic nature of the purified 34 kDa protein was determined by ELISA against serum proteins of patients suffering from typhoid fever and finally confirmed by immunoblot analysis. Antisera against the purified 34 kDa outer membrane protein of Salmonella typhi was produced and was used to recognize the epitope on the surface of an intact Salmonella typhi bacterium. RESULTS: The antigenic 34 kDa protein from the outer membrane of Salmonella typhi was identified, purified and characterized. The antigenecity of purified protein was confirmed by using antibodies present in serum of patient suffering from typhoid fever. It was also observed that antibody against 34 kDa outer membrane protein recognizes intact Salmonella typhi cells. CONCLUSIONS: It is established from the study that 34 kDa protein is antigenic in nature and antibody against this protein can also recognize epitopes on intact Salmonella typhi cells. Furthermore, this protein can be a good source material to produce vaccine against typhoid fever.