Search tips
Search criteria

Results 1-25 (34)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
1.  Association between Prevalence of Chloroquine Resistance and Unusual Mutation in pfmdr-I and pfcrt Genes in India 
This study deals with the underlying causes of failure of chloroquine in the treatment of Plasmodium falciparum infection in some malaria-endemic regions of India. Samples were collected from 141 patients in Purulia from March of 2007 to April of 2008. In vitro drug susceptibility tests, parasitic DNA isolation followed by polymerase chain reaction, and restriction fragment-length polymorphisms of different codons of the pfcrt gene (76) and pfmdr-I genes (86, 1042, and 1246) were assessed. The responses of 141 patients to chloroquine were determined. Prevalence of double pfmdr-I (58.16%) mutation (86Y+1246Y) and some (14.89%) single pfcrt mutations with triple pfmdr-I mutation (76T+86Y+1042D+1246Y) were found. Interestingly, double pfmdr-I mutation (86Y and 1246Y codons) was observed with the early treatment failure cases. These results show, for the first time in India that in vitro chloroquine resistance and in vivo chloroquine treatment failure were caused by double pfmdr-I (P < 0.001) mutation.
PMCID: PMC3752744  PMID: 23509121
3.  Pansclerotic morphea: A male child with hemiatrophy of lower limb 
Morphea is a variant of localized scleroderma in which lesions are usually limited to the skin and subcutaneous tissue. Pansclerotic morphea is a rare atrophying and sclerosing type of morphea. It can follow a comparatively benign course with spontaneous resolution of symptoms, or sometimes can lead to a variety of complications resulting in progressive disability. We report a case of Pansclerotic morphea in an 8-year-old male child involving one lower extremity with extension to the lower trunk. It was associated with deformity and hemiatrophy of that limb, leading to restriction of normal day-to-day activity. The case is being reported in view of its rare occurrence in conjunction with other rarer features.
PMCID: PMC4030347  PMID: 24860754
Pansclerotic morphea; contracture; hemiatrophy
4.  Evolutionary implications of a third lymphocyte lineage in lampreys 
Nature  2013;501(7467):435-438.
Jawed vertebrates (gnathostomes) and jawless vertebrates (cyclostomes) have different adaptive immune systems1,2. Gnathostomes use T- and B-cell antigen receptors belonging to the immunoglobulin superfamily3,4. Cyclostomes, the lampreys and hagfish, instead use leucine-rich repeat proteins to construct variable lymphocyte receptors (VLRs), two types of which, VLRA and VLRB, are reciprocally expressed by lymphocytes resembling gnathostome T and B cells5–7. Here we define another lineage of T-cell-like lymphocytes that express the recently identified VLRC receptors8,9. Both VLRC+ and VLRA+ lymphocytes express orthologues of genes that gnathostome γδ and αβ T cells use for their differentiation, undergo VLRC and VLRA assembly and repertoire diversification in the ‘thymoid’ gill region, and express their VLRs solely as cell-surface proteins. Our findings suggest that the genetic programmes for two primordial T-cell lineages and a prototypic B-cell lineage were already present in the last common vertebrate ancestor approximately 500 million years ago. We propose that functional specialization of distinct T-cell-like lineages was an ancient feature of a primordial immune system.
PMCID: PMC3901013  PMID: 23934109
5.  Antileukemic Efficacy of Monomeric Manganese-Based Metal Complex on KG-1A and K562 Cell Lines 
ISRN Oncology  2013;2013:709269.
Transitional metals and metal compounds have been used in versatile platforms for biomedical applications and therapeutic intervention. Severe side effects of anticancer drugs produce an urgent urge to develop new classes of anticancer agents with great potency as well as selectivity. In this background, recent studies demonstrate that monomeric manganese (MnII) thiocyanate complex (MMTC) holds great promise to exert effective antileukemic effects. MMTC was developed by a simple chemical reaction and characterized by elemental analyses, thermal analyses, and Fourier transform infrared (FTIR) spectroscopy. Anti-leukemic efficacy of the developed MMTC was estimated in KG-1A (AML) and K562 (CML) cell lines. Cell viability study, drug uptake assay, cellular redox balance (GSH and GSSG level), nitric oxide (NO) release level, reactive oxygen species (ROS) formation, alteration of mitochondrial membrane potential (MMP), and DNA fragmentation revealed that MMTC was able to produce significant antiproliferative effects on both cell lines at 25 μg mL−1 without showing any toxicological impact on normal lymphocytes. These findings will enlighten the biomedical application of manganese-based metal complexes as anti-leukemic agents.
PMCID: PMC3817708  PMID: 24223312
6.  Sequencing of the sea lamprey (Petromyzon marinus) genome provides insights into vertebrate evolution 
Nature genetics  2013;45(4):415-421e2.
Lampreys are representatives of an ancient vertebrate lineage that diverged from our own ~500 million years ago. By virtue of this deeply shared ancestry, the sea lamprey (P. marinus) genome is uniquely poised to provide insight into the ancestry of vertebrate genomes and the underlying principles of vertebrate biology. Here, we present the first lamprey whole-genome sequence and assembly. We note challenges faced owing to its high content of repetitive elements and GC bases, as well as the absence of broad-scale sequence information from closely related species. Analyses of the assembly indicate that two whole-genome duplications likely occurred before the divergence of ancestral lamprey and gnathostome lineages. Moreover, the results help define key evolutionary events within vertebrate lineages, including the origin of myelin-associated proteins and the development of appendages. The lamprey genome provides an important resource for reconstructing vertebrate origins and the evolutionary events that have shaped the genomes of extant organisms.
PMCID: PMC3709584  PMID: 23435085
7.  Symptomatic Infantile Hepatic Hemangioendothelioma Successfully Treated with Steroid 
Journal of Clinical Neonatology  2013;2(4):187-189.
A case of hepatic hemangioendothelioma presenting as congestive cardiac failure in a neonate is being reported which was managed successfully with oral prednisolone, resulting in improvement of symptoms and regression of tumor within 3 months.
PMCID: PMC3883215  PMID: 24404532
Congestive cardiac failure; congestive cardiac failure; hemangioendothelioma; liver tumor; prednisolone
8.  The Anaesthesia Gas Supply System 
Indian Journal of Anaesthesia  2013;57(5):489-499.
The anaesthesia gas supply system is designed to provide a safe, cost-effective and convenient system for the delivery of medical gases at the point of-use. The doctrine of the anaesthesia gas supply system is based on four essential principles: Identity, continuity, adequacy and quality. Knowledge about gas supply system is an integral component of safe anaesthetic practice. Mishaps involving the malfunction or misuse of medical gas supply to operating theatres have cost many lives. The medical gases used in anaesthesia and intensive care are oxygen, nitrous oxide, medical air, entonox, carbon dioxide and heliox. Oxygen is one of the most widely used gases for life-support and respiratory therapy besides anaesthetic procedures. In this article, an effort is made to describe the production, storage and delivery of anaesthetic gases. The design of anaesthesia equipment must take into account the local conditions such as climate, demand and power supply. The operational policy of the gas supply system should have a backup plan to cater to the emergency need of the hospital, in the event of the loss of the primary source of supply.
PMCID: PMC3821266  PMID: 24249882
Cylinders; manifolds; medical gases; pipelines; vacuum-insulated evaporators
9.  Bispectral index score and observer's assessment of awareness/sedation score may manifest divergence during onset of sedation: Study with midazolam and propofol 
Indian Journal of Anaesthesia  2013;57(4):351-357.
Correlation between the clinical and electroencephalogram-based monitoring has been documented sporadically during the onset of sedation. Propofol and midazolam have been studied individually using the observer's assessment of awareness/sedation (OAA/S) score and Bispectral index score (BIS). The present study was designed to compare the time to onset of sedation for propofol and midazolam using both BIS and OAA/S scores, and to find out any correlation.
A total of 46 patients (18-60 years, either sex, American Society of Anesthesiologists (ASA) I/II) posted for infraumbilical surgeries under spinal anaesthesia were randomly allocated to receive either injection propofol 1 mg/kg bolus followed by infusion 3 mg/kg/h (Group P, n=23) or injection midazolam 0.05 mg/kg bolus followed by infusion 0.06 mg/kg/h (Group M, n=23). Spinal anaesthesia was given with 2.5 ml to 3.0 ml of 0.5% bupivacaine heavy. When sensory block reached T6 level, sedation was initiated. The time to reach BIS score 70 and time to achieve OAA/S score 3 from the start of study drug were noted. OAA/S score at BIS score 70 was noted. Data from 43 patients were analyzed using SPSS 12 for Windows.
Time to reach BIS score 70 using propofol was significantly lower than using the midazolam (P<0.05). Time to achieve OAA/S score 3 using propofol was comparable with midazolam (P=0.358).
A divergence exists between the time to reach BIS score 70 and time to achieve OAA/S score 3 using midazolam, compared with propofol, during the onset of sedation.
PMCID: PMC3800326  PMID: 24163448
Bispectral index score; midazolam; observer's assessment of awareness/sedation score; propofol; sedation
10.  Comparative Genomics and Genome Evolution 
Current Genomics  2012;13(2):85.
PMCID: PMC3308328  PMID: 23024599
11.  Immune Related Genes Underpin the Evolution of Adaptive Immunity in Jawless Vertebrates 
Current Genomics  2012;13(2):86-94.
The study of immune related genes in lampreys and hagfish provides a unique perspective on the evolutionary genetic underpinnings of adaptive immunity and the evolution of vertebrate genomes. Separated from their jawed cousins at the stem of the vertebrate lineage, these jawless vertebrates have many of the gene families and gene regulatory networks associated with the defining morphological and physiological features of vertebrates. These include genes vital for innate immunity, inflammation, wound healing, protein degradation, and the development, signaling and trafficking of lymphocytes. Jawless vertebrates recognize antigen by using leucine-rich repeat (LRR) based variable lymphocyte receptors (VLRs), which are very different from the immunoglobulin (Ig) based T cell receptor (TCR) and B cell receptor (BCR) used for antigen recognition by jawed vertebrates. The somatically constructed VLR genes are expressed in monoallelic fashion by T-like and B-like lymphocytes. Jawless and jawed vertebrates thus share many of the genes that provide the molecular infrastructure and physiological context for adaptive immune responses, yet use entirely different genes and mechanisms of combinatorial assembly to generate diverse repertoires of antigen recognition receptors.
PMCID: PMC3308329  PMID: 23024600
Adaptive immunity; Antigen receptor; Evolution; Jawless vertebrate; Leucine-rich repeat; Phylogeny; Somatic diversification; Variable Lymphocyte Receptor.
12.  Evolutionary Genomics of Immunoglobulin-Encoding Loci in Vertebrates 
Current Genomics  2012;13(2):95-102.
Immunoglobulins (or antibodies) are an essential element of the jawed vertebrate adaptive immune response system. These molecules have evolved over the past 500 million years and generated highly specialized proteins that recognize an extraordinarily large number of diverse substances, collectively known as antigens. During vertebrate evolution the diversification of the immunoglobulin-encoding loci resulted in differences in the genomic organization, gene content, and ratio of functional genes and pseudogenes. The tinkering process in the immunoglobulin-encoding loci often gave rise to lineage-specific characteristics that were formed by selection to increase species adaptation and fitness. Immunoglobulin loci and their encoded antibodies have been shaped repeatedly by contrasting evolutionary forces, either to conserve the prototypic structure and mechanism of action or to generate alternative and diversified structures and modes of function. Moreover, evolution favored the development of multiple mechanisms of primary and secondary antibody diversification, which are used by different species to effectively generate an almost infinite collection of diverse antibody types. This review summarizes our current knowledge on the genomics and evolution of the immunoglobulin-encoding loci and their protein products in jawed vertebrates.
PMCID: PMC3308330  PMID: 23024601
Antibodies; gnathostomes; genomic organization; cladistic markers; microRNA; comparative genomics.
13.  Efficacy of intravenous dexamethasone to reduce incidence of postoperative sore throat: A prospective randomized controlled trial 
Sore throat and hoarseness are common complications of endotracheal intubation. It may be very distressing for the patient and may lead to sleep disturbances and unpleasant memories.
Materials and Methods:
This prospective double-blinded randomized control trial was aimed to determine the efficacy of prophylactic intravenous dexamethasone to reduce the incidence of postoperative sore throat at 1 hour after tracheal extubation. Ninety six patients of either sex aged between 18 to 60 years scheduled for elective surgeries needing general anesthesia with endotracheal intubation, were randomly allocated into two groups A and B. The patients received either intravenous 0.2 mg/kg dexamethasone (group A, n = 48) or normal saline (group B, n = 47) just before induction. Trachea was intubated with appropriate size disposable endotracheal tubes for securing the airway. Follow up for the incidence of sore throat, cough and hoarseness was done at 1, 6 and 24 hours post-extubation.
At 1 hour post-extubation, the incidence of sore throat in the control group was 48.9% compared with 18.8% in the dexamethasone group (P<0.002).
Prophylactic intravenous dexamethasone in a dose of 0.2 mg/kg can reduce the incidence of postoperative sore throat at 1 hour post-extubation by around 30%, with the efficacy being around 60%.
PMCID: PMC3511945  PMID: 23225928
Intravenous dexamethasone; Intubation; Postoperative sore throat
14.  Submental intubation: A journey over the last 25 years 
Airway management in patients with faciomaxillary injuries is challenging due to disruption of components of upper airway. The anesthesiologist has to share the airway with the surgeons. Oral and nasal routes for intubation are often not feasible. Most patients have associated nasal fractures, which precludes use of nasal route of intubation. Intermittent intraoperative dental occlusion is needed to check alignment of the fracture fragments, which contraindicates the use of orotracheal intubation. Tracheostomy in such situations is conventional and time-tested; however, it has life-threatening complications, it needs special postoperative care, lengthens hospital stay, and adds to expenses. Retromolar intubation may be an option, But the retromolar space may not be adequate in all adult patients. Submental intubation provides intraoperative airway control, avoids use of oral and nasal route, with minimal complications. Submental intubation allows intraoperative dental occlusion and is an acceptable option, especially when long-term postoperative ventilation is not planned. This technique has minimal complications and has better patients’ and surgeons’ acceptability. There have been several modifications of this technique with an expectation of an improved outcome. The limitations are longer time for preparation, inability to maintain long-term postoperative ventilation and unfamiliarity of the technique itself. The technique is an acceptable alternative to tracheostomy for the good per-operative airway access.
PMCID: PMC3409936  PMID: 22869933
Adult; intubation; intratracheal methods; maxillofacial injuries/surgery; oral/methods; surgery
15.  Intravenous infusion of ketamine-propofol can be an alternative to intravenous infusion of fentanyl-propofol for deep sedation and analgesia in paediatric patients undergoing emergency short surgical procedures 
Indian Journal of Anaesthesia  2012;56(2):145-150.
Paediatric patients often present with different painful conditions that require immediate surgical interventions. Despite a plethora of articles on the ketamine–propofol combination, comprehensive evidence regarding the suitable sedoanalgesia regime is lacking due to heterogeneity in study designs.
This prospective, randomized, double-blind, active–controlled trial was conducted in 100 children, of age 3–14 years, American Society of Anesthesiologist physical status IE-IIE, posted for emergency short surgical procedures. Patients were randomly allocated to receive either 2 mL of normal saline (pre-induction) plus calculated volume of drug from the 11 mL of ketamine–propofol solution for induction (group PK, n=50) or fentanyl 1.5 μg/kg diluted to 2 mL with normal saline (pre-induction) plus calculated volume of drug from the 11 mL of propofol solution for induction (group PF, n=50). In both the groups, the initial bolus propofol 1 mg/kg i.v. (assuming the syringes contained only propofol, for simplicity) was followed by adjusted infusion to achieve a Ramsay Sedation Scale score of six. Mean arterial pressure (MAP) was the primary outcome measurement.
Data from 48 patients in group PK and 44 patients in group PF were available for analysis. Hypotension was found in seven patients (14.6%) in group PK compared with 17 (38.6%) patients in group PF (P=0.009). Intraoperative MAP was significantly lower in group PF than group PK when compared with baseline.
The combination of low-dose ketamine and propofol is more effective and a safer sedoanalgesia regimen than the propofol–fentanyl combination in paediatric emergency short surgical procedures in terms of haemodynamic stability and lesser incidence of apnoea.
PMCID: PMC3371489  PMID: 22701205
Drug combinations; fentanyl; ketamine; paediatric emergency; procedural sedation; propofol
17.  Multiple-injection thoracic paravertebral block as an alternative to general anaesthesia for elective breast surgeries: A randomised controlled trial 
Indian Journal of Anaesthesia  2012;56(1):27-33.
General anaesthesia is currently the conventional technique used for surgical treatment of breast lump. Paravertebral block (PVB) has been used for unilateral procedures such as thoracotomy, breast surgery, chest wall trauma, hernia repair or renal surgery.
We compared unilateral thoracic PVB with general anaesthesia (GA) in 60 consenting ASA physical status I and II female patients of 18–65 years age, scheduled for unilateral breast surgery. Patients were randomly assigned into two groups, P (n=30) or G (n=30), to receive either PVB or GA, respectively.
The average time to first post-operative analgesic requirement at visual analogue scale score≥4 (primary endpoint) was significantly longer in group P (303.97±76.08 min) than in group G (131.33±21.36 min), P<0.001. Total rescue analgesic (Inj. Tramadol) requirements in the first 24 h were 105.17±20.46 mg in group P as compared with 176.67±52.08 mg in group G (P<0.001). Significant post-operative nausea and vomiting requiring treatment occurred in three (10.34%) patients of the PVB group and eight (26.67%) patients in the GA group.
The present study concludes that unilateral PVB is more efficacious in terms of prolonging post-operative analgesia and reducing morbidities in patients undergoing elective unilateral breast surgery.
PMCID: PMC3327066  PMID: 22529416
Unilateral breast surgery; anaesthetic technique; unilateral thoracic paravertebral block; general anaesthesia; post-operative analgesia; multiple-injection technique
18.  Alteration of some cellular function in amikacin resistant Pseudomonas aeruginosa transfected macrophages: a time dependent approach 
To evaluate the free radical generation and antioxidant enzymes status in murine peritoneal macrophage during in vitro amikacin resistant Pseudomonas aeruginosa (ARPA) treatment with different time interval.
Peritoneal macrophages were treated with 1×108 CFU/mL ARPA cell suspension in vitro for different time interval (1, 2, 3, 6, 12, and 24 h) and super oxide anion generation, NO generation, reduced glutathione level and antioxidant enzymes status were analyzed.
Super oxide anion generation and NO generation got peak at 12 h, indicating maximal free radical generation through activation of NADPH oxidase in murine peritoneal macrophages during ARPA transfection. Reduced glutathione level and antioxidant enzymes status were decreased significantly (P<0.05) with increasing time of ARPA transfection. All the changes in peritoneal macrophages after 12 h in vitro ARPA transfection had significant difference (P<0.05).
From this study, it may be summarized that in vitro ARPA infection not only generates excess free radical but also affects the antioxidant system and glutathione cycle in murine peritoneal macrophage.
PMCID: PMC3614218  PMID: 23569818
Antioxidant enzyme; ARPA; Oxidative stress; Peritoneal macrophage; Free radical generation
19.  A comparative study of infusions of phenylephrine, ephedrine and phenylephrine plus ephedrine on maternal haemodynamics in elective caesarean section 
Indian Journal of Anaesthesia  2011;55(6):578-583.
This randomized double blind study was started with an objective of management of spinal anaesthesia-induced hypotension in elective caesarean section by combining two commonly used vasopressors – ephedrine and phenylephrine in half of their usual doses with an expectation of reducing their foetomaternal side effects.
One hundred and thirty two patients were randomized into three groups to receive either 100 μg/ml phenylephrine (group-P, n=31) or 3 μg/ml ephedrine (group-E, n=33) or 50 mg phenylephrine plus 1.5 mg ephedrine/ml (group-PE, n=29). Immediately after spinal injection the study solution was started prophylactically in every patient at the rate of 40 ml/h. A predefined algorithm was used to adjust the infusion rate according to the systolic blood pressure (SBP).
Mean fall of SBP was significantly more in group-E than group-P (P=0.009) and group-PE (P=0.013). This was not significantly different when compared between group-P and group-PE (P=0.9). Episodes of hypotension and tachycardia were more in group-E than the other two groups. Statistically significant tachycardia was seen in Group-E than that in other two groups. Incidence of bradycardia and hypertension did not differ significantly among the groups. Maternal nausea and Apgar score were also comparable in three groups.
Current study claims that prophylactic phenylephrine 100 mg/ml is a better choice than ephedrine (3 mg/ml) or 50 mcg phenylephrine plus 1.5 mg ephedrine/ml in prevention of spinal anaesthesia-induced hypotension in elective caesarean section. Combination of two drugs in half the usual dose has no added advantage over phenylephrine, but this is better than ephedrine alone.
PMCID: PMC3249864  PMID: 22223901
Bradycardia; elective caesarean section; hypotension; spinal anaesthesia; vasopressors
20.  Comparative Genomics and Evolution of the Alpha-Defensin Multigene Family in Primates 
Molecular Biology and Evolution  2010;27(10):2333-2343.
Defensin genes encode small cationic antimicrobial peptides that form an important part of the innate immune system. They are divided into three families, alpha (α), beta (β), and theta (θ), according to arrangement of the disulfide bonding pattern between cysteine residues. Considering the functional importance of defensins, investigators have studied the evolution and the genomic organization of defensin genes. However, these studies have been restricted mainly to β-defensins. To understand the evolutionary dynamics of α-defensin genes among primates, we identified the α-defensin repertoires in human, chimpanzee, orangutan, macaque, and marmoset. The α-defensin genes in primates can be classified into three phylogenetic classes (class I, II, and III). The presence of all three classes in the marmoset indicates that their divergence occurred before the separation of New World and Old World monkeys. Comparative analysis of the α-defensin genomic clusters suggests that the makeup of the α-defensin gene repertoires between primates is quite different, as their genes have undergone dramatic birth-and-death evolution. Analysis of the encoded peptides of the α-defensin genes indicates that despite the overall high level of sequence divergence, certain amino acid residues or motifs are conserved within and between the three phylogenetic classes. The evolution of α-defensins in primates, therefore, appears to be governed by two opposing evolutionary forces. One force stabilizes specific amino acid residues and motifs to preserve the functional and structural integrity of the molecules and the other diversifies the sequences generating molecules with a wide range of activities against a large number of pathogens.
PMCID: PMC2981490  PMID: 20457584
alpha-defensin gene; primate evolution; innate immunity; comparative genomics; positive selection; birth-and-death evolution
21.  Internalization of Staphylococcus aureus in Lymphocytes Induces Oxidative Stress and DNA Fragmentation: Possible Ameliorative Role of Nanoconjugated Vancomycin 
Staphylococcus aureus is the most frequently isolated pathogen causing bloodstream infections, skin and soft tissue infections and pneumonia. Lymphocyte is an important immune cell. The aim of the present paper was to test the ameliorative role of nanoconjugated vancomycin against Vancomycin-sensitive Staphylococcus aureus (VSSA) and vancomycin-resistant Staphylococcus aureus (VRSA) infection-induced oxidative stress in lymphocytes. VSSA and VRSA infections were developed in Swiss mice by intraperitoneal injection of 5 × 106 CFU/mL bacterial solutions. Nanoconjugated vancomycin was adminstrated to VSSA- and VRSA-infected mice at its effective dose for 10 days. Vancomycin was adminstrated to VSSA- and VRSA-infected mice at a similar dose, respectively, for 10 days. Vancomycin and nanoconjugated vancomycin were adminstrated to normal mice at their effective doses for 10 days. The result of this study reveals that in vivo VSSA and VRSA infection significantly increases the level of lipid peroxidation, protein oxidation, oxidized glutathione level, nitrite generation, nitrite release, and DNA damage and decreases the level of reduced glutathione, antioxidant enzyme status, and glutathione-dependent enzymes as compared to control group, which were increased or decreased significantly near to normal in nanoconjugated vancomycin-treated group. These findings suggest the potential use and beneficial role of nanoconjugated vancomycin against VSSA and VRSA infection-induced oxidative stress in lymphocytes.
PMCID: PMC3175730  PMID: 21941607
22.  Authors’ reply 
Indian Journal of Anaesthesia  2011;55(5):547-548.
PMCID: PMC3237168  PMID: 22174485
23.  MicroRNA 125b inhibition of B cell differentiation in germinal centers 
International Immunology  2010;22(7):583-592.
MicroRNAs 125a and 125b are predicted to be able to bind to the B lymphocyte-induced maturation protein-1 (BLIMP-1) and IFN regulatory protein-4 (IRF-4) transcription factors, which are essential for plasma cell differentiation. A computational survey of the human and mouse genomes revealed that miR-125a and miR-125b are members of a multigene family located in paralogous clusters. The miR-125a cluster on chromosome 19 in humans includes miR-99b and let-7e, whereas the miR-125b cluster on chromosome 21 includes miR-99a and miR-let-7c. Our analysis of the expression profiles for these six miRs during B lineage differentiation indicated that mature miR-125a, miR-125b, miR-99b and let-7e transcripts are preferentially expressed by the actively dividing centroblasts in germinal centers (GC). However, miR-99b and let-7e are not predicted to bind BLIMP-1 or IRF-4 transcripts, and binding to the untranslated region of BLIMP-1 and IRF-4 messenger RNAs could be confirmed only for miR-125b. When the effect of miR-125b over-expression on terminal B cell differentiation was evaluated in an LPS-responsive B cell line, the induction of BLIMP-1 expression and IgM secretion was inhibited in this model system. Furthermore, miR-125b over-expression inhibited the differentiation of primary B cells and compromised the survival of cultured myeloma cells. These findings suggest that miR-125b promotes B lymphocyte diversification in GC by inhibiting premature utilization of essential transcription factors for plasma cell differentiation.
PMCID: PMC2892362  PMID: 20497960
BLIMP-1; centroblasts; gene regulation; IRF-4; MicroRNA; plasma cell differentiation
24.  Fibreoptic aided retrograde intubation in an oral cancer patient 
Indian Journal of Anaesthesia  2011;55(2):202-203.
PMCID: PMC3106402  PMID: 21712885
25.  Analysis of the Immunoglobulin Light Chain Genes in Zebra Finch: Evolutionary Implications 
Molecular Biology and Evolution  2009;27(1):113-120.
All jawed vertebrates produce immunoglobulins (IGs) as a defense mechanism against pathogens. Typically, IGs are composed of two identical heavy chains (IGH) and two identical light chains (IGL). Most tetrapod species encode more than one isotype of light chains. Chicken is the only representative of birds for which genomic information is currently available and is an exception to the above rule because it encodes only a single IGL isotype (i.e., lambda). Here, we show that the genome of zebra finch, another bird species, encodes a single IGL isotype, that is, lambda, like the chicken. These results strongly suggest that the second isotype (i.e., kappa) present in both reptiles and mammals was lost in a very early stage of bird evolution. Furthermore, we show that both chicken and zebra finch contain a single set of functional variable, joining, and constant region genes and multiple variable region pseudogenes. The latter finding suggests that this type of genomic organization was already present in the common ancestor of these bird species and remained unchanged over a long evolutionary time. This conservation is in contrast with the high levels of variation observed in the mammalian IGL loci. The presence of a single functional variable region gene followed by multiple variable pseudogenes in zebra finch suggest that this species may be generating antibody diversity by a gene conversion-like mechanism like the chicken.
PMCID: PMC2877555  PMID: 19744999
immunoglobulin genes; cladistic molecular markers; antibody diversity; gene conversion; comparative genomics; repetitive elements

Results 1-25 (34)