A fast survey on recent developments in designing colorimetric and fluorescent sensors for the selective detection of essential amino acids.

Owing to the biological significance of various amino acids, developing accurate and cost-effective sensing techniques for the selective detection of amino acids has recently attracted growing interest. This review discusses the recent advancements of chemosensors in the selective detection of only essential amino acids out of a total of twenty amino acids, which have been applied in chemosensing research, and the mechanism of their action. The focus is directed towards the detection of the most important essential amino acids, like leucine, threonine, lysine, histidine, tryptophan and methionine, since isoleucine and valine are yet to be explored in regard to chemosensing. According to their chemical and fluorescence properties, different sensing techniques, such as the reaction-based approach, DNA-based sensors, nanoparticle formation, coordination ligand binding, host-guest chemistry, the fluorescence indicator displacement (FID) approach, electrochemical sensors, carbon dot-based sensors, MOF-based sensors and metal-based techniques, have been described.

Brown tumor of the knee as the first presentation of primary hyperparathyroidism caused by parathyroid adenoma: A case report.

Brown tumor of the knee is a focal benign cystic lesion of bone. The etiopathogenesis of brown tumor is believed to be abnormal bone metabolism in patients with hyperparathyroidism. We present a case of a 32-year-old male with recurrent knee pain, weakness of the lower limb and a nodular mass on left inferior lobe of thyroid. Timely identification of the underlying cause and localization of lesion(s) is important because the management and prognosis vary based on the etiology. The diagnosis of a brown tumor is the result of the sum of the medical history of patients with clinical, radiographic imaging, histopathological, hematological, and biochemical laboratory investigations.

Translocation of gut flora and its role in sepsis.

Bacterial translocation is the invasion of indigenous intestinal bacteria through the gut mucosa to normally sterile tissues and the internal organs. Sometimes instead of bacteria, inflammatory compounds are responsible for clinical symptoms as in systemic inflammatory response syndrome (SIRS). The difference between sepsis and SIRS is that pathogenic bacteria are isolated from patients with sepsis but not with those of SIRS. Bacterial translocation occurs more frequently in patients with intestinal obstruction and in immunocompromised patients and is the cause of subsequent sepsis. Factors that can trigger bacterial translocation from the gut are host immune deficiencies and immunosuppression, disturbances in normal ecological balance of gut, mucosal barrier permeability, obstructive jaundice, stress, etc. Bacterial translocation occurs through the transcellular and the paracellular pathways and can be measured both directly by culture of mesenteric lymph nodes and indirectly by using labeled bacteria, peripheral blood culture, detection of microbial DNA or endotoxin and urinary excretion of non-metabolisable sugars. Bacterial translocation may be a normal phenomenon occurring on frequent basis in healthy individuals without any deleterious consequences. But when the immune system is challenged extensively, it breaks down and results in septic complications at different sites away from the main focus. The factors released from the gut and carried in the mesenteric lymphatics but not in the portal blood are enough to cause multi-organ failure. Thus, bacterial translocation may be a promoter of sepsis but not the initiator. This paper reviews literature on the translocation of gut flora and its role in causing sepsis.

Anti-ganglioside antibodies in patients with Guillain Barré syndrome and other neurological disorders.

A study was performed on 59 Guillain-Barré syndrome (GBS) cases, 58 neurological controls (NC) and 60 non-neurological controls (NNC) to investigate the association of anti-ganglioside antibodies in GBS and other neurological disorders. Campylobacter jejuni was isolated from 5.7% of GBS patients. Anti-ganglioside immunoglobulin G was present in 82% and immunoglobulin M in 46% in acute inflammatory demyelinating polyneuropathy patients, 70% and 44% respectively in acute motor axonal neuropathy subgroup and 38% each in acute motor sensory axonal neuropathy subgroup. Though high intensity of anti-gangliosides was present in the GBS patients, the NC patients also had adequate anti-gangliosides compared with the NNC group.

Effect of biotherapeutics on antitoxin IgG in experimentally induced Clostridium difficile infection.

PURPOSE: Recurrent diarrhoea after successful treatment of primary Clostridium difficile associated disease (CDAD) occurs due to bowel flora alterations and failure to mount an effective antibody response. Apart from antibiotics, risk factors include immunosuppressive and acid-suppressive drug administration. Biotherapeutics such as probiotic and epidermal growth factor (EGF) may offer potential effective therapy for CDAD. MATERIALS AND METHODS: The effect of biotherapeutics in mounting an antibody response against C. difficile toxins was studied in BALB/c mice challenged with C. difficile after pre-treatment with ampicillin, lansoprazole or cyclosporin. Sera from sacrificed animals were estimated for antitoxin IgG by enzyme linked immunosorbent assay. RESULTS: Antitoxin IgG was significantly higher (P<0.05) in C. difficile challenged groups compared to unchallenged controls, but insignificant (P>0.05) in animals in which C. difficile was given after pre-treatment with cyclosporin compared to those without any pre-treatment, or pre-treatment with antibiotic or lansoprazole. In inter-subgroup comparisons also significant anomaly in production of antitoxin IgG was found. The antitoxin IgG levels were raised in animals administered C. difficile after pre-treatment with ampicillin, but lower in animals administered cyclosporin. High levels of antitoxin IgG were also found in the serum samples of animals receiving lansoprazole and C. difficile. CONCLUSIONS: Probiotics showed their beneficial effect by boosting the immune response as seen by production of antitoxin IgG. Oral administration of EGF did not affect the immune response to C. difficile toxins as significant increase was not observed in the serum antitoxin IgG levels in any of the groups investigated.

Preliminary investigation of environmental prevalence of Clostridium difficile affecting inpatients in a north Indian hospital.

A preliminary study was conducted to see the prevalence of Clostridium difficile in patients and their environment in a tertiary care hospital. Seventy-nine fecal specimens from hospitalized patients, 176 swab samples from beds and 48 from hands of hospital personnel were investigated. Sixty-three patients received antibiotics and 14 proton pump inhibitors. Abdominal pain was observed in 16 patients with fever in 15 of them. C. difficile culture was positive in 12.6% patients at initial sampling but none were toxin-positive. Eight patients developed diarrhea and five were both culture and toxin-positive. Fifty-one percent of bed swab samples and 62.5% of hand swab samples were culture positive. Similarly 8.5% of bed swab samples and 4.2% of hand swab samples were positive for toxins A and B. The environmental cross-infection between patients and carriage by hospital personnel are plausible sources of C. difficile infection and spread in our hospital.

Campylobacter jejuni infection in Guillain-Barré syndrome: a prospective case control study in a tertiary care hospital.

BACKGROUND: Guillain-Barré syndrome (GBS), is a common post-infectious polyradiculoneuropathy worldwide. The commonest implicated causative organism the world over is Campylobacter jejuni (C. jejuni). This study was carried out to determine the relationship between C. jejuni infection and GBS in an Indian setting. MATERIALS AND METHODS: This prospective study was carried out on a cohort of 50 patients with GBS who were treated in a tertiary care hospital in India. Based on electrophysiological findings the patients were divided into various subtypes. Serology for C. jejuni (Immunoglogulin G, IgG and Immunoglogulin, IgM) using an enzyme-linked immunosorbent assay method (ELISA) was done both in patients and 40 age, sex and geographically matched controls. RESULTS: Evidence of recent C. jejuni infection was present in 30% of GBS patients compared to 8% of controls (15/50 vs. 3/40 P<0.005). Eight (47%) C. jejuni-positive patients reported symptoms of gastroenteritis 4-30 days (mean 13 days) prior to onset of GBS. Of the 15 patients with evidence of C. jejuni infection, 10 (67%) patients had axonal type of GBS. Axonal variety of GBS presented in a younger age group compared to acute inflammatory demyelinating polyradiculoneuropathy (AIDP) patients (mean age: axonal vs. AIDP: 30.11 + 13.73 vs. 40.2 + 18.77). C. jejuni-positive patients presented mainly in spring and winter and had a similar age and sex incidence as compared to the rest of the GBS patients. CONCLUSIONS: Preceding C. jejuni infection is common among GBS patients and is often associated with the axonal variety of GBS. Axonal variety of GBS generally presents in a younger age group as compared to AIDP.

Treatment of endodontically induced periapical lesions using hydroxyapatite, platelet-rich plasma, and a combination of both: An in vivo study.

AIM AND OBJECTIVES: To evaluate bone regeneration in endodontically induced periapical lesions using Hydroxyapatite, Platelet-Rich Plasma (PRP), and a combination of Hydroxyapatite and Platelet-Rich Plasma for a period of one year. MATERIALS AND METHODS: Twenty systemically healthy patients of both genders between the ages 20 and 40 years were included. To qualify, the patient had to have a tooth where non-surgical root canal therapy had failed, periapical radiolucency was present, and periapical root end surgery was required. The bony defect had to be confined to the apical area, with the bone covering the entire root surface coronally, with an intact lingual cortical plate. Patients were randomly divided into four groups, with five patients each, as follows: Group I - Replacement with Hydroxyapatite, Group II - Replacement with PRP, Group III - Replacement with PRP and Hydroxyapatite, and Group IV - Control group with no substitutes. The patients were evaluated both clinically and radiographically. RESULTS: The radiographic evaluation revealed that Group I patients showed complete bone regeneration with evidence of a trabecular pattern, at the end of one year, Group II patients showed complete bone regeneration at the end of nine months, Group III patients showed complete bone regeneration at the end of six months, and Group IV patients showed bone regeneration, which was not satisfactory even after one year. CONCLUSIONS: The PRP and Hydroxyapatite combination facilitated better and faster bone regeneration when compared to PRP alone.

An affinity-based genome walking method to find transgene integration loci in transgenic genome.

Identifying a good transgenic event from the pool of putative transgenics is crucial for further characterization. In transgenic plants, the transgene can integrate in either single or multiple locations by disrupting the endogenes and/or in heterochromatin regions causing the positional effect. Apart from this, to protect the unauthorized use of transgenic plants, the signature of transgene integration for every commercial transgenic event needs to be characterized. Here we show an affinity-based genome walking method, named locus-finding (LF) PCR (polymerase chain reaction), to determine the transgene flanking sequences of rice plants transformed by Agrobacterium tumefaciens. LF PCR includes a primary PCR by a degenerated primer and transfer DNA (T-DNA)-specific primer, a nested PCR, and a method of enriching the desired amplicons by using a biotin-tagged primer that is complementary to the T-DNA. This enrichment technique separates the single strands of desired amplicons from the off-target amplicons, reducing the template complexity by several orders of magnitude. We analyzed eight transgenic rice plants and found the transgene integration loci in three different chromosomes. The characteristic illegitimate recombination of the Agrobacterium sp. was also observed from the sequenced integration loci. We believe that the LF PCR should be an indispensable technique in transgenic analysis.

Cost-effective screening of pooled faecal specimens from patients with nosocomial diarrhoea for Clostridium perfringens enterotoxin.

PURPOSE: Clostridium perfringens is a significant cause of nosocomial AAD. The prevalence of C. perfringens enterotoxin (CPE)-positive stool specimens in hospitalised patients is very low in the Indian setting making the diagnostics very expensive. Therefore, a cost-effective diagnostic approach to screen faecal specimens for CPE was devised. MATERIALS AND METHODS: Faecal specimens from 540 hospitalised patients with various ailments and from 340 healthy subjects were investigated for CPE. An aliquot of pooled faecal supernatants was made by mixing 100 µl each of 10 specimens to be tested. Each aliquot was investigated for the presence of CPE by an enzyme immunoassay. A repetition of the assay was done with individual specimens of the pooled aliquots from each positive well as seen visually by colour development. RESULTS: Of the 540 patient specimens tested, 405 (75%) patients were on antibiotics, the predominant ones being cephalosporins, penicillin, quinolones, aminoglycosides, etc. During the time of sampling, diarrhoea was present in 481 (89%), abdomen pain in 203 (37.6%) and fever in 242 (44.8%) patients. C. perfringens enterotoxin was positive in nine wells of the 540 pooled test specimens whereas all of the pooled 340 control samples were negative. Repeat of individual specimens comprising the nine wells with positive samples helped to identify the individual patients positive for CPE. CONCLUSION: Only two CPE kits were needed for a total of 880 faecal specimens tested. The cost-effective diagnostic approach to screen faecal specimens for CPE, as described herein will help to save institutional resources.

Molecular characterization and expression of a gene encoding cytosolic Hsp90 from Pennisetum glaucum and its role in abiotic stress adaptation.

Heat shock protein 90 (Hsp90) is an abundant and highly conserved molecular chaperone that is essential for viability in eukaryotes. They have a crucial role in the folding of a set of proteins involved in the regulation of many essential cellular pathways and also re-folding of stress-denatured polypeptides. However, their exact function is still not clearly elucidated. In this study the full-length cDNA encoding for Hsp90 polypeptide and its corresponding gene was isolated from Pennisetum glaucum (designated PgHsp90). PgHsp90 cDNA encoded for a polypeptide of 698 amino acids with a predicted molecular mass of 80.3kDa and shared a high sequence homology (97-81%) to other plant cytosolic Hsp90s and shared less sequence homology (40-45%) to organelle and endoplasmic reticulum specific Hsp90 isoforms. A deduced amino acid sequence possessed three structural domains: N-terminus (1-211) ATP binding domain, middle (281-540) client protein interacting domain and C-terminus (541-698) dimerization domain; the N-terminus and middle domain is linked by a charged linker domain (212-280). It possesses the five-conserved amino acid signature sequence motifs characteristic of the Hsp90 family and a C-terminus MEEVD penta-peptide characteristic of the cytosolic Hsp90 isoform. The predicted quaternary architecture generated for PgHsp90 through molecular modeling was globally akin to that of yeast Hsp90. The PgHsp90 gene consists of 3 exons and 2 introns. The position and phasing of these introns were conserved in other plant cytosolic Hsp90 genes. Recombinant PgHsp90 protein was expressed in E. coli and purified to homogeneity, which possessed in vitro chaperone activity. E. coli expressing PgHsp90 protein showed enhanced tolerance to heat, salt and dehydration stresses. The quantitative up-regulation of PgHsp90 gene expression positively correlates in response to different stresses to meet the additional demand for protein folding support. Cumulatively, the in vivo and in vitro experiments indicated that PgHsp90 plays an adaptive or protective role to counter the stress induced protein damage.

Comparison of the fracture toughness and wear resistance of indirect composites cured by conventional post curing methods and electron beam irradiation.

AIM: To compare the fracture toughness and wear resistance of indirect composites cured by conventional post curing methods and electron beam irradiation. MATERIALS AND METHODS: Forty specimens were randomly assigned into four groups of ten each and were subjected to various post curing methods. Fracture toughness and wear resistance tests were performed and the results were tabulated and analyzed statistically using Kruskal Wallis and Mann-Whitney U test. RESULTS: It was found that Inlay system showed higher values followed by electron beam irradiation. CONCLUSION: Electron beam irradiation of dental composites gives comparable mechanical properties to other post curing systems. It can be concluded that further studies with increased radiation dose should be performed to improve the mechanical properties of indirect composites.

Endodontic microbiology.

Root canal therapy has been practiced ever since 1928 and the success rate has tremendously increased over the years owing to various advancements in the field. One main reason is the complete understanding of the microbiology involved in the endodontic pathology. This has helped us to modify the conventional treatment plans and effectively combat the microorganisms. Now, studies are aiming to explore the characteristics of the "most" resistant organism and the methods to eliminate them. This article gives an insight of the microbiology involved in endodontic pathology and discusses its role in our treatment procedure. Information from original reviews listed in PubMed, published from 1995 to 2010, has been mainly included in this review.

Established and potential risk factors for Clostridum difficile infection.

Clostridium difficile is the aetiological agent for almost all cases of pseudo membranous colitis and 15-25% of antibiotic associated diarrhoea. In recent years, C. difficile associated disease (CDAD) has been increasing in frequency and severity due to the emergence of virulent strains. Severe cases of toxic mega colon may be associated with mortality rates of 24-38%. The prevalence of CDAD is global and the incidence varies considerably from place to place. In the initial stages of its discovery, C. difficile infection was regarded mainly as an outcome of antibiotic intake and not as a life threatening disease. Intervention by man has produced conditions making C. difficile a significant cause of morbidity and mortality. The recent outbreak of CDAD in Quebec has sent the alarm bells ringing. Apart from a threefold increase in the incidence of CDAD, clinicians have also reported a higher number of cases involving toxic mega colon, colectomy or death. Among all the risk factors, inclusive of the host and the environmental factors, antibiotics are the most important ones. Surgical patients comprise 55-75% of all patients with CDAD due to the fact that perioperative prophylaxis requires the use of antibiotics. However, other drugs such as immunosuppressants and proton pump inhibitors are also important risk factors. Thus CDAD is a growing nosocomial and public health challenge. Additionally, the recognition of community acquired CDAD signals the presence of several risk factors. In this review, the established and potential risk factors of CDAD, along with the epidemiology, diagnostic modalities, management and preventive measures of the disease have been elaborated.

Bacterial profile of dairy products sold in Chandigarh.

Gastrointestinal infections are known to occur due to bacterial contamination of dairy products. A total of 141 dairy products viz. kulfi, ice cream and softy samples were investigated bacteriologically. Staphylococcus was the predominant organism isolated followed by Klebsiella pneumoniae, Escherichia coli and Campylobacter. Two of the samples also yielded Yersinia. The total bacterial counts obtained ranged from 2 x 10(1) to 5.2 x 10(11) colony forming units per ml (CFU/ml) for kulfi, 4 x 10(1) to 9 x 10(9) CFU/ml for ice cream and 2 x 10(1) to 2 x 10(10) CFU/ml for softy samples. The high degree of bacterial contamination seen indicates poor hygienic conditions and faults in manufacturing/handling of dairy products during and after processing and production.

Faecal excretion of brush border membrane enzymes in patients with Clostridium difficile diarrhoea.

PURPOSE: To look for the presence of intestinal brush border membrane (BBM) enzymes in the faecal samples of patients with Clostridium difficile association. METHODS: One hundred faecal samples were investigated for C.difficile toxin (CDT). Simultaneous assays for faecal excretion of intestinal BBM enzymes viz., disaccharidases, alkaline phosphatase (AP) and leucine aminopeptidase (LAP) were also done. RESULTS: C. difficile toxin was detected in 25 (25%) of the samples with a titre ranging from 10 to 160. No significant difference (p>0.05) was seen between the CDT positive and negative groups with any of the disaccharidases studied. However, significant increase (p< 0.05) in the AP excretion was observed in the CDT positive patients compared to the CDT negative group. In contrast to this, a significant decrease (p< 0.001) in the LAP enzyme excretion was observed in the latter group. CONCLUSIONS: The results of this study suggest that there is a significant disturbance in the intestinal BBM enzymes in patients with C. difficile diarrhoea.