Water-Stable, Eight-electron Acceptor Drives Anion∙∙∙Water Assisted Tunable Ionic Self-Assembly and Proton Conduction.

Organic π-scaffolds are being envisaged for new-age electron- and ion-responsive materials that can accumulate electrons as well as transport proton. However, such systems are extremely rare as electron-deficient scaffolds are unstable in aqueous solution. Here we detail the synthesis of a water-stable core-naphthalenediimide-nitrobenzyl-viologen based tetra-cation, which accumulates up to eight-electrons within an exceptionally narrow potential window of +0.05 V and -1.12 V. The supramolecular interactions and the ensuing ionic framework are tunable based on the three anions, e.g., Cl-, Br- and PF6-, that are investigated in this work. The ionic framework is formed and supported by a range of H-bonds, in which, the nitro benzyl groups act as pillars connecting the 1D water-tapes and the halide anions. The water molecules are hydrogen-bonded with the halide anions and bestow a facile pathway for the proton conduction, with proton conductivity up to 3.19 x 10-3 S cm-1. In contrast, the ionic assembly formed by the lipophilic PF6- anions do not host the water tapes and consequently the proton conductivity is found to be four orders of magnitude lower. This is a unique example, whereby proton conductivity is realized and is tunable within a highly electron-deficient, eight-electron acceptor, water-stable ionic supramolecular system.

A novel diterpenic derivative produced by Streptomyces chrestomyceticus ADP4 is a potent inhibitor of biofilm and virulence factors in Candida albicans and C. auris.

AIM: Isolation, identification, structural and functional characterization of potent anti-Candida compound with specific antagonistic activities against significant human pathogens, Candida albicans and C. auris. METHODS AND RESULTS: The compound (55B3) was purified from the metabolites produced by Streptomyces chrestomyceticus ADP4 by employing column chromatography. The structure of 55B3 was determined from the analyses of spectral data that included LCMS, nuclear magnetic resonance, FTIR, and UV spectroscopies. It was identified as a novel derivative of diterpenic aromatic acid, 3-(dictyotin-11'-oate-15'α, 19'ß-olide)-4-(dictyotin-11'-oate-15″α, 19″ß-olide)-protocatechoic acid. The compound displayed potent antifungal and anti-biofilm activities against C. albicans ATCC 10231 (Minimum Inhibitory Concentration, MIC90:14.94 ± 0.17 µgmL-1 and MBIC90: 16.03 ± 1.1 µgmL-1) and against C. auris CBS 12372 (MIC90: 21.75 ± 1.5 µgmL-1 and Minimum Biofilm Inhibitory Concentration, MBIC90: 18.38 ± 1.78 µgmL-1). Further, pronounced inhibition of important virulence attributes of Candida spp., e.g. yeast-to-hyphae transition, secretory aspartyl proteinase and phospholipase B by 55B3 was noted at subinhibitory concentrations. A plausible mechanism of anti-Candida action of the compound appeared to be the inhibition of ergosterol biosynthesis, which was inhibited by 64 ± 3% at the MIC90 value. The non-cytotoxic attribute of the compound was noted in the liver cell line (HepG2 cells). CONCLUSION: The present work led to the discovery of a novel diterpenic derivative produced by S. chrestomyceticus ADP4. The compound displayed potent anti-Candida activity, particularly against the two most significant human pathogens, C. albicans and C. auris, which underlined its significance as a potential drug candidate for infections involving these pathogens.

Halogen-Bonded Assemblies of Arylene Imides and Diimides: Insight from Electronic, Structural, and Computational Studies.

Halogen-bonding interactions in electron-deficient π scaffolds have largely been underexplored. Herein, the halogen-bonding properties of arylene imide/diimide-based electron-deficient scaffolds were studied. The influence of scaffold size, from small (phthalimide) to moderately sized (pyromellitic diimide or naphthalenediimides) to large (perylenediimide), axial-group modification, and number of halo substituents on the halogen bonding and its self-assembly was probed in a set of nine compounds. The structural modification leads to tunable optical and redox properties. The first reduction potential E 1 / 2 1 ranges between -1.09 and -0.17 V (vs. SCE). Two of the compounds, that is, 6 and 9, have deep-lying LUMOs with values reaching -4.2 eV. Single crystals of all nine systems were obtained, which showed Br⋅⋅⋅O, Br⋅⋅⋅Br, or Br⋅⋅⋅π halogen-bonding interactions, and a few systems are capable of forming all three types. These interactions lead to halogen-bonded rings (up to 12-membered), which propagate to form stacked 1D, 2D, or corrugated sheets. A few outliers were also identified, for example, molecules that prefer C-H⋅⋅⋅O hydrogen bonding over halogen bonding, or noncentrosymmetric rather than centrosymmetric organization. Computational studies based on Atoms in Molecules and Natural Bond Orbital analysis provided further insight into the halogen-bonding interactions. This study can lead to a predictive design tool-box to further explore related systems on surfaces reinforced by these weak directional forces.

Emergence of human West Nile Virus infection among pediatric population in Madhya Pradesh, India.

Human infections caused by West Nile virus (WNV) mostly remain subclinical and self-limited. However, nearly 20% infected people suffer from febrile illness and very few of them (<1%) may get neuroinvasive illness. Mortality has been reported among children. India somehow has reported very less number of WNV cases in the past. We collected cerebrospinal fluid (CSF) samples from 75 pediatric age group patients clinically suffering from acute encephalitis syndrome. Three of these samples were positive by reverse transcriptase polymerase chain reaction using pan flavivirus primers. On sequencing of the 212 bp long-amplified fragment, it was found to be WNV belonging to lineage 1. This is probably the first report of WNV causing encephalitis from this central part of India.

Ionic Assembly, Anion-π, Magnetic, and Electronic Attributes of Ambient Stable Naphthalenediimide Radical Ions.

Organic spin-based molecular materials are considered to be attractive for the generation of functional materials with emergent optoelectronic, magnetic, or magneto-conductive properties. However, the major limitations to the utilization of organic spin-based systems are their high reactivity, instability, and propensity for dimerization. Herein, we report the synthesis, characterization, and magnetic and electronic studies of three ambient stable radical ions (1 a.+ , 1 b.+ , and 1 c.+ ). The radical ions 1 b.+ and 1 c.+ with BPh4 - and BF4 - counter anions, respectively, were synthesized in excellent yields by means of anion metathesis of 1 a.+ with Br- as its counter anion. Notably, synthesis of 1 a.+ was achieved in an ecofriendly, solvent-free protocol. The radical ions were characterized by means of single-crystal X-ray diffraction studies, which revealed the discrete nature of the radical ions and extensive hydrogen-bonding interactions within the radical ions and with the counter anions. Thus, radical ions can be organized to form infinite supramolecular arrays using weak noncovalent interactions. In addition, the Br- , BF4 - , and BPh4 - anions formed diverse types of anion-π interactions with the naphthalene and imide rings of the radical ions. The radical ions were characterized by means of X-band electron paramagnetic resonance (EPR) spectroscopy in solution and in the solid state. Magnetic studies revealed their paramagnetic nature in the range of 10 to 300 K. The radical ions exhibited high resistivity approaching the gigaohm (GΩ) scale. In addition, the radical ions exhibited panchromism.

Molecular diagnosis and ocular imaging of West Nile virus retinitis and neuroretinitis.

PURPOSE: To describe the ocular features of West Nile virus (WNV) infection proven by serology and molecular diagnostic techniques. DESIGN: Prospective case series. PARTICIPANTS: Fifty-two patients who presented to the uveitis clinic with ocular inflammatory signs and history of fever preceding ocular symptoms between January 2010 and January 2012 were enrolled for laboratory diagnosis. Serum samples were collected from 30 healthy controls from the same geographic area. METHODS: Patients were tested for all endemic infectious diseases that can cause ocular inflammation by serology or molecular diagnostics. When patients had positive antibodies for WNV, serum/plasma samples were tested by real-time reverse transcription (RT) polymerase chain reaction (PCR) and RT loop-mediated isothermal gene amplification assays. The PCR product was subjected to nucleotide sequencing. Fundus fluorescence angiography (FFA), optical coherence tomography (OCT), and indocyanine green angiography were performed. Visual prognosis was analyzed. MAIN OUTCOME MEASURES: Clinical signs (retinitis, neuroretinitis, and choroiditis) and ocular complications (decrease in vision). RESULTS: A total of 37 of 52 patients (71%) showed positive results for at least 2 laboratory tests for WNV. Fundus examination revealed discrete, superficial, white retinitis; arteritis; phlebitis; and retinal hemorrhages with or without macular star. The FFA revealed areas of retinal inflammation with indistinct borders, vascular and optic disc leakage, vessel wall staining, or capillary nonperfusion. Indocyanine green angiography confirmed choroidal inflammation in 1 of the patients who was diabetic. The OCT scan of the macula revealed inner retinal layer edema in active inflammation and retinal atrophy in late stage. At the final visit, 43% of patients had visual acuity better than 6/12. CONCLUSIONS: In addition to previously reported clinical signs, retinitis, neuroretinitis, and retinal vasculitis were seen in this population. Atrophy of the inner retinal layer was seen on OCT after resolution of inflammation. Visual prognosis was good in patients with focal retinitis and poor in patients with occlusive vasculitis. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Aza-Dipyrrinate Stabilized Compounds with a Low-Valent Main Group Element.

The possibility of using aza-dipyrromethene (a-DPM) ligands to stabilize compounds containing low-valent main group elements is demonstrated through the isolation of germylenes, a-DPM(p-tol)GeCl (2), a-DPM(Naph)GeCl (6), and a-DPM(Naph)GeN(TMS)2 (7) (tol=tolyl, Naph=naphthyl). Because of the presence of the a-DPM ligand, these germylenes exhibit an absorption maximum at around 640 nm, a highly red-shifted value previously unknown for germylenes.

Phylogeny and evolution of SARS-CoV-2 during Delta and Omicron variant waves in India.

SARS-CoV-2 evolution has continued to generate variants, responsible for new pandemic waves locally and globally. Varying disease presentation and severity has been ascribed to inherent variant characteristics and vaccine immunity. This study analyzed genomic data from 305 whole genome sequences from SARS-CoV-2 patients before and through the third wave in India. Delta variant was reported in patients without comorbidity (97%), while Omicron BA.2 was reported in patients with comorbidity (77%). Tissue adaptation studies brought forth higher propensity of Omicron variants to bronchial tissue than lung, contrary to observation in Delta variants from Delhi. Study of codon usage pattern distinguished the prevalent variants, clustering them separately, Omicron BA.2 isolated in February grouped away from December strains, and all BA.2 after December acquired a new mutation S959P in ORF1b (44.3% of BA.2 in the study) indicating ongoing evolution. Loss of critical spike mutations in Omicron BA.2 and gain of immune evasion mutations including G142D, reported in Delta but absent in BA.1, and S371F instead of S371L in BA.1 could explain very brief period of BA.1 in December 2021, followed by complete replacement by BA.2. Higher propensity of Omicron variants to bronchial tissue, probably ensured increased transmission while Omicron BA.2 became the prevalent variant possibly due to evolutionary trade-off. Virus evolution continues to shape the epidemic and its culmination.Communicated by Ramaswamy H. Sarma.

Differential immunotoxic effects of ethanol on murine EL-4 lymphoma and normal lymphocytes is mediated through increased ROS production and activation of p38MAPK.

Ethanol has been used to achieve thymic depletion in myasthenia gravis patients. Ethanol (95%) has also been used widely in the therapy of many tumors including hepatocellular carcinoma. In light of these findings, we delineated the differential immunotoxic behavior and mechanism of lower concentration of ethanol towards murine EL-4 lymphoma and its normal counterpart lymphocytes. EL-4 lymphoma and normal lymphocytes were cultured with ethanol (0%-5%) for 6 h and cytotoxicity was measured by various methods. EL-4 cells treated with ethanol showed concentration-dependent loss of viability at 2%-5% ethanol concentration and exhibit proliferative arrest at preG1 stage. Acridine-orange and ethidium-bromide staining indicated that ethanol induced death in EL-4 cells, by induction of both apoptosis and necrosis which was further supported by findings of DNA-fragmentation and trypan blue dye exclusion test. However, treatment of lymphocytes with similar concentration of ethanol did not show any death-associated parameters. Furthermore, ethanol induced significantly higher ROS generation in EL-4 cells as compared to lymphocytes and caused PARP cleavage and activation of apoptotic proteins like p53 and Bax, in EL-4 cells and not in normal lymphocytes. In addition, ethanol exposure to EL-4 cells led to phosphorylation of p38MAPK, and upregulation of death receptor Fas (CD95). Taken together, these results suggest that ethanol upto a concentration of 5% caused no significant immunotoxicity towards normal lymphocytes and induced cell death in EL-4 cells via phosphorylation of p38MAPK and regulation of p53 leading to further activation of both extrinsic (Fas) and intrinsic (Bax) apoptotic markers.

Spectrum of Inherited Bleeding Disorder with Special Reference to von Willebrand Disease in Eastern India.

Background The objective of this study is to study the prevalence, clinical spectrum, and hematological profile of inherited bleeding disorder with special reference to von Willebrand disease in eastern India. Materials and Methods This prospective study was done in a tertiary care center in the eastern part of India over 2 years. Detailed history and clinical findings were noted in a proforma. Laboratory analysis included prothrombin time, activated partial thromboplastin time, bleeding time, and fibrinogen assay along with tests related to specific factor assay. Results One hundred and five patients were diagnosed as suffering with the inherited bleeding disorder out of a total of 1,204 patients. The age of patients ranged from 13 days to 35 years. The most common presenting clinical feature was prolonged bleeding after cut (76.19%). Out of 105 patients, 97 patients (92.38%) had coagulation defect, 5 patients (4.76%) had von Willebrand disease (vWD), and 3 patients (2.85%) had platelet defect. Most common coagulation defect was hemophilia A (84 cases), followed by hemophilia B (8 cases). Other rare congenital factor deficiencies were seen in five cases (5.15%). Only platelet defect was Glanzmann's thrombasthenia (GT). The age of vWD patients ranged from 4.5 years to 24 years. Forty percent patients with vWD disease were type 1 followed by 40% of type 2N and 20% of type 3 vWD. Conclusion vWD was not so common in eastern India. vWD was present only in 4.76% cases in this study. The most common coagulation defect was hemophilia A (86.59%) in our study. GT was present in only 2.85% cases.

Synthesis of a Highly Electron-Deficient, Water-Stable, Large Ionic Box: Multielectron Accumulation and Proton Conductivity.

π-acidic boxes exhibiting electron reservoir and proton conduction are unprecedented because of their instability in water. We present the synthesis of one of the strongest electron-deficient ionic boxes showing e- uptake as well as proton conductivity. Two large anions fit in the box to form anion-π interactions and form infinite anion-solvent wires. The box with NO3-···water wires confers high proton conductivity and presents the first example that manifests redox and ionic functionality in an organic electron-deficient macrocycle.

Repositioning of tubocurarine as analgesic and anti-inflammatory agent: Exploring beyond myorelaxant activity.

BACKGROUND AND PURPOSE: Tubocurarine (d-TC), a non-depolarizing competitive blocker of nicotinic acetylcholine receptors is extensively utilized for the relaxation of skeletal muscles. Drug repositioning is a forthright approach to reduce the cost and speed up drug development process. Herein, we have attempted to evaluate the analgesic and anti-inflammatory activity of d-TC for its possible repurposing in pain and inflammation-related issues. EXPERIMENTAL APPROACH: We examined the soluble epoxide hydrolase inhibitory (sEHI) activity of d-TC employing in silico high throughput screening protocols, in vitro cell-free sEH inhibitory assay, and in in vivo rodent models for its repositioning in pain and inflammation-related disorders. KEY RESULTS: In molecular docking study, d-TC displayed impressive hydrogen bonding interactions within the cavity of sEH enzyme with good docking score. d-TC also exhibited notable sEH inhibitory activity (IC50 3.72 nm) at the in vitro assay. Oral absorption capability of d-TC (0.1 and 0.2 mg/mL) was determined using an in vitro everted intestinal sac model employing rat ileum tissue that revealed significant oral absorption of d-TC. Besides, in vivo studies revealed that oral administration of d-TC (0.1 and 0.2 mg/kg) in rodents significantly attenuated hyperalgesia (cold plate test, tail immersion test and formalin test) and inflammation (estimation of rectal temperature, acetic acid induced pleurisy test and cotton pellet-induced granuloma test) induced in robust preclinical models. Conclusion and implications These findings are novel and warrant immediate efforts to reposition d-TC as a new therapeutic candidate in the management of hyperalgesia, inflammation, and associated conditions.

Comparative complete genome analysis of dengue virus type 3 circulating in India between 2003 and 2008.

Dengue is endemic in most parts of the tropics including India. So far, complete genome information for Indian dengue isolates is not available. In the present study, we characterized the genome of three dengue type 3 viruses isolated from India. The genomes of all three viruses were found to be 10,707 bp long with an ORF encoding 3390 aa. Extensive molecular phylogenetic analysis based on comparison of the complete genome and envelope gene classified the recent Indian viruses into genotype III (lineage III), revealing a shift of lineage from lineage V. The sequence analysis revealed several non-conservative changes in major structural proteins. This study clearly indicates that the genotype III (lineage III) dengue type 3 viruses have been continuously circulating in major parts of India since 2003 and are responsible for the recent major outbreaks all over India. This is the first extensive study on complete genome analysis of dengue type 3 viruses in India.

Molecular epidemiology of novel swine origin influenza virus (S-OIV) from Gwalior, India, 2009.

BACKGROUND: The H1N1pandemic virus is a newly emergent human influenza A virus that is closely related to a number of currently circulating pig viruses in the 'classic North American' and 'Eurasian' swine influenza virus lineages and thus referred as S-OIV. Since the first reports of the virus in humans in April 2009, H1N1 virus has spread to 168 countries and overseas territories. India also witnessed severe H1N1 pandemic virus epidemic with considerable morbidity and mortality in different parts starting from May 2009. FINDINGS: The suspected swine flu outbreak from Gwalior India during October- December 2009 was confirmed through S-OIV HA gene specific RT-LAMP and real time RT-PCR. Positive samples through CDC real time and Lamp assay were further processed for isolation of the virus. Full HA gene sequencing of the H1N1 isolates of Gwalior, India revealed 99% homology with California and other circulating novel swine flu viruses. Three major changes were observed at nucleotide level, while two major amino acid shifts were observed at the position C9W and I30M corresponding to the ORF with prototype strain. The HA gene sequence phylogeny revealed the circulation of two genetically distinct lineages belonging to Clade VII and Clade I of S-OIV. CONCLUSIONS: Our findings also supported the earlier report about circulation of mixed genogroups of S-OIV in India. Therefore continuous monitoring of the genetic makeup of this newly emergent virus is essential to understand its evolution within the country.

Development of a simple fed-batch process for the high-yield production of recombinant Japanese encephalitis virus protein.

Japanese encephalitis (JE) is one of the leading causes of acute encephalopathy affecting children and adolescents in the tropics. Optimization of media was carried out for enhanced production of recombinant JE virus envelope domain III (EDIII) protein in Escherichia coli. Furthermore, batch and fed-batch cultivation process in E. coli was also developed in optimized medium. Expression of this protein in E. coli was induced with 1 mM isopropyl-beta-thiogalactoside and yielded an insoluble protein aggregating to form inclusion bodies. The inclusion bodies were solubilized in 8 M urea, and the protein was purified under denaturing conditions using Ni-NTA affinity chromatography. After fed-batch cultivation, the recombinant E. coli resulted in cell dry weight and purified protein about 36.45 g l(-1) and 720 mg l(-1) of culture, respectively. The purity of the recombinant JE virus EDIII protein was checked by sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis, and reactivity of this protein was determined by Western blotting and ELISA with JE virus-infected human serum samples. These results establish the application of this protein to be used for the diagnosis of JE virus infection or for further studies in vaccine development. This process may also be suitable for the high-yield production of other recombinant viral proteins.

Synthesis of Stable, High-SOMO Zwitterionic Radicals: Enabling Intermolecular Electron Transfer between Naphthalenediimides.

Synthesis to enhance the electron donor ability of organic radicals has not been attempted due to reactivity challenges. Herein, naphthalenediimide-based (NDI•±) zwitterionic radicals are synthesized and isolated bestowing SOMO levels up to -4.04 eV. As a result, reduction of the NDI is realized with NDI•± radicals in their ground states. Notably, reduction of the NDI unit applying a π-electron donor is unprecedented and has been limited to inorganic/organometallic reagents or by light-driven excited states.

Molecular and Supramolecular Multiredox Systems.

The design and synthesis of molecular and supramolecular multiredox systems have been summarized. These systems are of great importance as they can be employed in the next generation of materials for energy storage, energy transport, and solar fuel production. Nature provides guiding pathways and insights to judiciously incorporate and tune the various molecular and supramolecular design aspects that result in the formation of complex and efficient systems. In this review, we have classified molecular multiredox systems into organic and organic-inorganic hybrid systems. The organic multiredox systems are further classified into multielectron acceptors, multielectron donors and ambipolar molecules. Synthetic chemists have integrated different electron donating and electron withdrawing groups to realize these complex molecular systems. Further, we have reviewed supramolecular multiredox systems, redox-active host-guest recognition, including mechanically interlocked systems. Finally, the review provides a discussion on the diverse applications, e. g. in artificial photosynthesis, water splitting, dynamic random access memory, etc. that can be realized from these artificial molecular or supramolecular multiredox systems.

Interleukin 6 and disease transformation in chronic myeloid leukemia: A Northeast Indian population study.

BACKGROUND: Interleukin 6 (IL6) has been suggested to be a valuable prognostic marker in chronic myeloid leukemia (CML). IL6 is a pleiotropic cytokine and plays an important role in immune response, hematopoiesis, and acute phase response. IL6 is regarded as a prominent target for clinical interventions. OBJECTIVE: The aim of the present study was to investigate the serum levels of IL6 in CML to provide greater insight to their role in disease transformation in Indian patients. MATERIALS AND METHODS: A total of 50 CML cases and 10 acute lymphocytic leukemia (ALL) cases along with 20 healthy controls were included in the study between 2015 and 2016. About 4 mL blood samples were collected from all cases in plain vial and serum was separated. Levels of IL6 were determined in all cases by enzyme-linked immunosorbent assay. RESULTS: The study suggests that both ALL and CML are associated with significantly elevated serum IL6 level than the healthy control group. Mean levels of serum IL6 are 223.4 ± 53.403 pg/mL in CML, 71.020 ± 29.549 pg/mL in ALL, and 5.360 ± 0.467 pg/mL in healthy control group. Serum IL6 correlated with different phases of CML. Mean IL6 levels are 50.93 ± 29.37 pg/mL in chronic phase (CP), 69.02 ± 22.60 pg/mL in accelerated phase (AP), and 652.77 ± 124.62 pg/mL in blast crisis (BC) phase of CML. In compared to CP and AP, in BC, IL-6 is significantly elevated ( P = 0.00 and 0.00, respectively); however, we did not find a significant difference in IL-6 serum levels between CP and AP ( P = 0.703). CONCLUSION: Study suggests that the detection of IL6 level in newly diagnosed patient can predict the severity of the disease. There might be association of level of IL6 with the disease transformation.

L-Arginine reverses radiation-induced immune dysfunction: the need for optimum treatment window.

The aim of the present study was to investigate the protective efficacy of l-arginine in mitigating the injury induced by 2 Gy of total-body gamma radiation (TBI). Mice exposed to radiation (TBI group) had significantly decreased spleen weight, splenocyte numbers and bone marrow cellularity. Administration of l-arginine 2 h after TBI (TBI + l-arginine group) was effective in reducing the radiation-induced depletion of spleen and bone marrow cellularity but was not effective when administered before TBI (l-arginine + TBI group). The radiation-induced decrease in Con A-induced spleen cell proliferation, specific antibody response of spleen B cells to sheep red blood cells, and spleen RNA content was reversed in mice in the TBI + l-arginine group. The radiation-induced increase in serum TNF-alpha levels, serum nitrate/nitrite (NOx) levels, spleen DNA fragmentation, spleen nitric oxide synthase (NOS) activity, spleen inducible NOS (iNOS) activity, and hepatic iNOS activity was reversed in mice in the TBI + l-arginine group. l-Arginine administered before TBI could not reverse these changes. Mice in the TBI + l-arginine group had significantly increased spleen arginase activity compared to mice from either the TBI or l-arginine + TBI group. The results suggest the importance of the time of administration of l-arginine and the l-arginine pathway in mitigating the radiation-induced host immune dysfunction.

Activated protein C resistance in deep venous thrombosis.

Several risk factors for deep venous thrombosis (DVT) have been identified, and inherited thrombophilias constitute a significant proportion of them. The most common inherited thrombophilia is activated protein C (APC) resistance, and factor V Leiden is the most common cause of APC resistance. The high prevalence of APC resistance in Caucasians is established, and the prevalence among persons of Asian and African descent has been shown to be low in previous studies. Twenty-three patients with lower limb DVT were included in the study. Diagnosis was confirmed by duplex ultrasonography. Patients were tested for APC resistance with use of the STA Staclot APC-R system (Diagnostica Stago, Asnieres, France), as per the manufacturer's guidelines. Ten patients (43.5%) tested positive for APC resistance, while 13 (56.5%) tested negative. APC resistance, although considered a rarity, has been found to have a high prevalence in patients with DVT from the northeastern region of India. APC resistance estimation should be done for all patients with DVT.