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Cryoreduction EPR/ENDOR/step-annealing measurements with substrate complexes of oxy-gsNOS (3; gsNOS is nitric oxide synthase from Geobacillus stearothermophilus) confirm that Compound I (6) is the reactive heme species that carries out the gsNOS-catalyzed (Stage I) oxidation of L-arginine to N-hydroxy-L-arginine (NOHA), whereas the active species in the (Stage II) oxidation of NOHA to citrulline and HNO/NO(-) is the hydroperoxy-ferric form (5). When 3 is reduced by tetrahydrobiopterin (BH4), instead of an externally supplied electron, the resulting BH4(+) radical oxidizes HNO/NO(-) to NO. In this report, radiolytic one-electron reduction of 3 and its complexes with Arg, Me-Arg, and NO(2)Arg was shown by EPR and (1)H and (14,15)N ENDOR spectroscopies to generate 5; in contrast, during cryoreduction of 3/NOHA, the peroxo-ferric-gsNOS intermediate (4/NOHA) was trapped. During annealing at 145 K, ENDOR shows that 5/Arg and 5/Me-Arg (but not 5/NO(2)Arg) generate a Stage I primary product species in which the OH group of the hydroxylated substrate is coordinated to Fe(III), characteristic of 6 as the active heme center. Analysis shows that hydroxylation of Arg and Me-Arg is quantitative. Annealing of 4/NOHA at 160 K converts it first to 5/NOHA and then to the Stage II primary enzymatic product. The latter contains Fe(III) coordinated by water, characteristic of 5 as the active heme center. It further contains quantitative amounts of citrulline and HNO/NO(-); the latter reacts with the ferriheme to form the NO-ferroheme upon further annealing. Stage I delivery of the first proton of catalysis to the (unobserved) 4 formed by cryoreduction of 3 involves a bound water that may convey a proton from L-Arg, while the second proton likely derives from the carboxyl side chain of Glu 248 or the heme carboxylates; the process also involves proton delivery by water(s). In the Stage II oxidation of NOHA, the proton that converts 4/NOHA to 5/NOHA likely is derived from NOHA itself, a conclusion supported by the pH invariance of the process. The present results illustrate how the substrate itself modulates the nature and reactivity of intermediates along the monooxygenase reaction pathway.

Photoinduced relaxation processes of five structurally characterized Pseudomonas aeruginosa Re(I)(CO)(3)(alpha-diimine)(HisX) (X = 83, 107, 109, 124, 126)Cu(II) azurins have been investigated by time-resolved (ps-ns) IR spectroscopy and emission spectroscopy. Crystal structures reveal the presence of Re-azurin dimers and trimers that in two cases (X = 107, 124) involve van der Waals interactions between interdigitated diimine aromatic rings. Time-dependent emission anisotropy measurements confirm that the proteins aggregate in mM solutions (D(2)O, KP(i) buffer, pD = 7.1). Excited-state DFT calculations show that extensive charge redistribution in the Re(I)(CO)(3) --> diimine (3)MLCT state occurs: excitation of this (3)MLCT state triggers several relaxation processes in Re-azurins whose kinetics strongly depend on the location of the metallolabel on the protein surface. Relaxation is manifested by dynamic blue shifts of excited-state nu(CO) IR bands that occur with triexponential kinetics: intramolecular vibrational redistribution together with vibrational and solvent relaxation give rise to subps, approximately 2, and 8-20 ps components, while the approximately 10(2) ps kinetics are attributed to displacement (reorientation) of the Re(I)(CO)(3)(phen)(im) unit relative to the peptide chain, which optimizes Coulombic interactions of the Re(I) excited-state electron density with solvated peptide groups. Evidence also suggests that additional segmental movements of Re-bearing beta-strands occur without perturbing the reaction field or interactions with the peptide. Our work demonstrates that time-resolved IR spectroscopy and emission anisotropy of Re(I) carbonyl-diimine complexes are powerful probes of molecular dynamics at or around the surfaces of proteins and protein-protein interfacial regions.

Nitric oxide synthases (NOSs) are heme-based monooxygenases that oxidize L-arginine to nitric oxide (NO), a signaling molecule and cytotoxic agent in higher organisms. Although NOS-like activity has been reported in many bacteria, only a few bacterial homologs of mammalian NOSs (mNOSs) have been characterized to date. In contrast to mNOSs, which possess both a catalytic and a reductase domain, the bacterial enzymes lack reductase domains and require the supply of suitable reductants to produce NO. A notable exception is a NOS from a gram-negative bacterium that contains a new type of reductase module. Remarkably, bacterial NOSs seem to have functions that differ from those of mNOSs, including nitration of different metabolites and protection against oxidative stress. Studies of bacterial NOSs will probably result in a better understanding of the mechanism of NO synthesis and unveil a variety of new functions for NO in microbes.

Carcinomatous transformation of ectopic thyroid elements within the thyroglossal tract is a rare entity. We report a case of primary papillary carcinoma of thyroid presenting within the thyroglossal duct cyst in a 23 year old gentleman. The patient presented to us, as a case of suprahyoid thyroglossal cyst with sub-lingual involvement and he underwent surgical excision of the entire thyroglossal tract by Sistrunk's approach. The post-operative histopathological diagnosis was of a papillary carcinoma within the thyroglossal duct cyst. Hence, the patient was evaluated for a malignant focus in the thyroid which proved negative. He was counseled regarding the possibility of developing Carcinoma in the thyroid gland and offered two options of further management viz., total thyroidectomy followed by life long thyroid suppression or watchful observation and follow up. As the patient belonged to the low risk group, he opted for the second option. He is presently kept under meticulous follow up and remains asymptomatic till date. We present the pre- and post-operative imaging, intra-operative findings, histo-pathological features and review the present world literature on this rare entity.

5-Styryl-4,5-cis-1,3-oxazole-2-one-4-carboxylic acid (CDRI-85/92) is a new proton pump inhibitor presently in advanced stage of preclinical trials as antiulcer pharmacophore. Since proton pump inhibitors are prodrugs requiring activation in acid environment, an ester prodrug of CDRI-85/92 was also synthesized. In view of the importance, a pharmacokinetic study of CDRI-85/92 and its ester prodrug was conducted after oral doses in rats. Following a 20 mg/kg oral dose of CDRI-85/92, the compound was detectable in the serum samples up to 24 h with a maximum serum concentration (C(max)) of 1838.40 +/- 101.16 ng/ml at 1.5 h and an elimination half-life of 4.96 h, whereas, multiple C(max) values of CDRI-85/92 were observed with oral doses (equivalent to 20 mg/kg of CDRI-85/92) of the ester prodrug of the compound. All the three C(max) values of the compound were lower than that after oral dose of CDRI-85/92. The compound was eliminated slowly from serum with an elimination half-life of 5.14 h. Moreover, the systemic availability of CDRI-85/92 also decreased from 6111 to 3463 ng x h/ml after the ester prodrug administration. The decrease in systemic availability of CDRI-85/92 could be due to its higher clearance after its ester prodrug administration.

A facile synthesis of 5,5'-(1,4-phenylene)bis(3-aryl-2-pyrazolines) 4a-g has been achieved by the cyclo-addition reaction of hydrazine hydrate with bis-substituted chalcones 3a-g, which in turn were prepared by the Clasien-Schmidt condensation of p-substituted acetophenones 1a-g with terephthaldehyde. Condensation of 4a-g with omega-bromoalkoxyphthalimides 5a-b afforded the titled compounds 6a-n, some of which exhibited significant antimalarial as well as antimicrobial activity.

Nitric oxide synthase (NOS) generates NO via a sequential two-step reaction [l-arginine (l-Arg) --> N-hydroxy-l-arginine (NOHA) --> l-citrulline + NO]. Each step of the reaction follows a distinct mechanism defined by the chemical environment introduced by each substrate bound to the heme active site. The dioxygen complex of the NOS enzyme from a thermophilic bacterium, Geobacillus stearothermophilus (gsNOS), is unusually stable; hence, it provides a unique model for the studies of the mechanistic differences between the two steps of the NOS reaction. By using CO as a structural probe, we found that gsNOS exhibits two conformations in the absence of substrate, as indicated by the presence of two sets of nu(Fe-CO)/nu(C-O) modes in the resonance Raman spectra. In the nu(Fe-CO) versus nu(C-O) inverse correlation plot, one set of data falls on the correlation line characterized by mammalian NOSs (mNOS), whereas the other set of data lies on a new correlation line defined by a bacterial NOS from Bacillus subtilis (bsNOS), reflecting a difference in the proximal Fe-Cys bond strength in the two conformers of gsNOS. The addition of l-Arg stabilizes the conformer associated with the mNOS correlation line, whereas NOHA stabilizes the conformer associated with the bsNOS correlation line, although both substrates introduce a positive electrostatic potential into the distal heme pocket. To assess how substrate binding affects Fe-Cys bond strength, the frequency of the Fe-Cys stretching mode of gsNOS was monitored by resonance Raman spectroscopy with 363.8 nm excitation. In the substrate-free form, the Fe-Cys stretching mode was detected at 342.5 cm(-1), similar to that of bsNOS. The binding of l-Arg and NOHA brings about a small decrease and increase in the Fe-Cys stretching frequency, respectively. The implication of these unique structural features with respect to the oxygen chemistry of NOS is discussed.

AtNOS1/AtNOA1 was identified as a nitric oxide-generating enzyme in plants, but that function has recently been questioned. To resolve issues surrounding AtNOA1 activity, we report the biochemical properties and a 2.36 A resolution crystal structure of a bacterial AtNOA1 ortholog (YqeH). Geobacillus YqeH fused to a putative AtNOA1 leader peptide complements growth and morphological defects of Atnoa1 mutant plants. YqeH does not synthesize nitric oxide from L-arginine but rather hydrolyzes GTP. The YqeH structure reveals a circularly permuted GTPase domain and an unusual C-terminal beta-domain. A small N-terminal domain, disordered in the structure, binds zinc. Structural homology among the C-terminal domain, the RNA-binding regulator TRAP, and the hypoxia factor pVHL define a recognition module for peptides and nucleic acids. TRAP residues important for RNA binding are conserved by the YqeH C-terminal domain, whose positioning is coupled to GTP hydrolysis. YqeH and AtNOA1 probably act as G-proteins that regulate nucleic acid recognition and not as nitric-oxide synthases.

Molecules and cellular mechanisms that regulate the process of cell division in malaria parasites remain poorly understood. In this study we isolate and characterize the four Plasmodium falciparum centrins (PfCENs) and, by growth complementation studies, provide evidence for their involvement in cell division. Centrins are cytoskeleton proteins with key roles in cell division, including centrosome duplication, and possess four Ca(2+)-binding EF hand domains. By means of phylogenetic analysis, we were able to decipher the evolutionary history of centrins in eukaryotes with particular emphasis on the situation in apicomplexans and other alveolates. Plasmodium possesses orthologs of four distinct centrin paralogs traceable to the ancestral alveolate, including two that are unique to alveolates. By real time PCR and/or immunofluorescence, we determined the expression of PfCEN mRNA or protein in sporozoites, asexual blood forms, gametocytes, and in the oocysts developing inside mosquito mid-gut. Immunoelectron microscopy studies showed that centrin is expressed in close proximity with the nucleus of sporozoites and asexual schizonts. Furthermore, confocal and widefield microscopy using the double staining with alpha-tubulin and centrin antibodies strongly suggested that centrin is associated with the parasite centrosome. Following the episomal expression of the four PfCENs in a centrin knock-out Leishmania donovani parasite line that exhibited a severe growth defect, one of the PfCENs was able to partially restore Leishmania growth rate and overcome the defect in cytokinesis in such mutant cell line. To our knowledge, this study is the first characterization of a Plasmodium molecule that is involved in the process of cell division. These results provide the opportunity to further explore the role of centrins in cell division in malaria parasites and suggest novel targets to construct genetically modified, live attenuated malaria vaccines.

Energy flow in biological structures often requires submillisecond charge transport over long molecular distances. Kinetics modeling suggests that charge-transfer rates can be greatly enhanced by multistep electron tunneling in which redox-active amino acid side chains act as intermediate donors or acceptors. We report transient optical and infrared spectroscopic experiments that quantify the extent to which an intervening tryptophan residue can facilitate electron transfer between distant metal redox centers in a mutant Pseudomonas aeruginosa azurin. Cu(I) oxidation by a photoexcited Re(I)-diimine at position 124 on a histidine(124)-glycine(123)-tryptophan(122)-methionine(121) beta strand occurs in a few nanoseconds, fully two orders of magnitude faster than documented for single-step electron tunneling at a 19 angstrom donor-acceptor distance.

CDRI-93/478 (1- [4-(4-fluorophenyl) piperazine-1-yl]-3-(2-oxopyrrolidin-1-yl) propane hydrochloride, an arylpiperazine derivative, is a potent anti-ischemic and anti-hypertensive agent and is in advanced stage of preclinical trials. In order to develop CDRI-93/478 into a clinical agent, the absorption, protein binding, pharmacokinetics, and excretion of the compound were investigated in male Sprague-Dawley rats. Oral absorption was evaluated in situ and in vivo, using the portal-venous concentration difference method. The compound showed negligible absorption (ka = 0.01 h(-1)) at pH 2.6. However, the rate of absorption of the compound at pH 7.4 was 0.6 h(-1) and was comparable to that observed in the in vivo study (ka, >0.58 h(-1)) in rats after a single 2 mg/kg oral dose. In vitro and in vivo protein binding studies using the ultrafiltration method showed that the compound was subject to low protein binding (<40%) and was independent of the substrate concentration over a range of 1-16 microg/ml. Pharmacokinetic parameters of the compound were determined after intravenous and oral administration of 0.6, 2 and 8 mg/kg doses using a model independent method. After oral administration, the compound showed the double-peak phenomenon, which could be due to the high water solubility (log P, 1.01 +/- 0.01), regional differences in the gastrointestinal absorption and enterohepatic recirculation effects. The absorption of CDRI-93/478 was rapid and showed a bioavailability of 69.9 +/- 5.1% (mean +/- S. D.) after 2 and 8 mg/kg oral dose. However, the pharmacokinetic parameters of the compound could not be determined after the 0.6 mg/kg oral dose due to insufficient data points. The studies following intravenous and oral administration demonstrated linear pharmacokinetics, low clearance and high volume of distribution over the dose range studied. The excretion studies after the 8 mg/kg oral dose indicated that the compound was not excreted through the feces and the urinary excretion was very low (<2%).

The Worldwide Protein Data Bank (wwPDB; wwpdb.org) is the international collaboration that manages the deposition, processing and distribution of the PDB archive. The online PDB archive at ftp://ftp.wwpdb.org is the repository for the coordinates and related information for more than 47 000 structures, including proteins, nucleic acids and large macromolecular complexes that have been determined using X-ray crystallography, NMR and electron microscopy techniques. The members of the wwPDB-RCSB PDB (USA), MSD-EBI (Europe), PDBj (Japan) and BMRB (USA)-have remediated this archive to address inconsistencies that have been introduced over the years. The scope and methods used in this project are presented.

A sensitive and reproducible high performance liquid chromatography (HPLC)-UV method for the determination of the novel anti-tuberculosis compound 1,2:5,6-di-O-isopropylidene-3-O-(phenyl cyclopropyl methanonyl)-alpha-D-glucofuranose (S-001-14) has been developed and validated in rat serum, urine and feces. Following extraction with hexane at alkaline pH, samples were separated on a reverse phase C18 column and quantified using UV detection at 267 nm. The mobile phase was 70% acetonitrile in ammonium acetate buffer (10 mmol/L, pH 6.0) with a flow rate of 1.0 ml/min. The method was used to determine the pharmacokinetics and excretion of S-001-14 after oral doses in rats. Linearity was satisfactory over the concentration range of 5-500 ng/ml (r2, > 0.99). Recoveries were > 90% and were consistent throughout the calibration range. The precision and accuracy were acceptable as indicated by relative standard deviation ranging from 2.72 to 9.54%, bias values ranging from 1.62 to 12.05%. Moreover, S-001-14 was stable in rat serum after being subjected to three freeze-thaw cycles and for 30 days on storage at - 60 degrees C. The method was used to determine the serum concentration-time profiles for S-001-14 after oral doses of 4, 100 and 200 mg/kg in rats. A linear pharmacokinetics was found in rats at 100 and 200 mg/kg doses with a long elimination half-life (approximately 24 h), wide distribution and bioavailability of approximately 13%. The excretion study after the 100 mg/kg oral dose revealed that S-001-14 was excreted in urine (0.002 +/- 0.001%) and feces (15.6 +/- 3.5%).

Gene function annotation remains a key challenge in modern biology. This is especially true for high-throughput techniques such as gene expression experiments. Vital information about genes is available electronically from biomedical literature in the form of full texts and abstracts. In addition, various publicly available databases (such as GenBank, Gene Ontology and Entrez) provide access to gene-related information at different levels of biological organization, granularity and data format. This information is being used to assess and interpret the results from high-throughput experiments. To improve keyword extraction for annotational clustering and other types of analyses, we have developed a novel text mining approach, which is based on keywords identified at the level of gene annotation sentences (in particular sentences characterizing biological function) instead of entire abstracts. Further, to improve the expressiveness and usefulness of gene annotation terms, we investigated the combination of sentence-level keywords with terms from the Medical Subject Headings (MeSH) and Gene Ontology (GO) resources. We find that sentence-level keywords combined with MeSH terms outperforms the typical 'baseline' set-up (term frequencies at the level of abstracts) by a significant margin, whereas the addition of GO terms improves matters only marginally. We validated our approach on the basis of a manually annotated corpus of 200 abstracts generated on the basis of 2 cancer categories and 10 genes per category. We applied the method in the context of three sets of differentially expressed genes obtained from pediatric brain tumor samples. This analysis suggests novel interpretations of discovered gene expression patterns.

Alveolar soft part sarcoma is a rare, aggressive malignancy of uncertain histologic origin and enigmatic clinical behaviour. It has a characteristic histopathological picture, with a propensity for vascular invasion and distant metastasis. We report a case of alveolar soft part sarcoma involving the tongue base in an adolescent female. She underwent laser assisted excision of the tongue base tumour followed by post-operative radiotherapy. The clinical presentation, histopathological picture, immunohistochemical & cytogenetic studies, radio-imaging, management protocols and prognosis of this tumor have been discussed.

Bulaquine (BQ) is a potent antirelapse antimalarial developed by CDRI, India. Bulaquine was rapidly absorbed in rats and rabbits with no distinct absorption phase while in monkeys a variable irregular absorption profile was observed. BQ was extensively converted to primaquine (PQ) after oral administration and the conversion was maximum in rats and minimum in rabbits, which is possibly due to the species difference. Clearance was higher in rats (3.2 l/h/kg) than in rabbits and monkeys (1.2 l/h/kg) and it was found be negligibly excreted in rat urine and feces. The elimination half-life in rats and rabbits was comparable after both oral and i.v. administration ( approximately 1.2 h). In all three species, PQ was resident in the body for a period longer than BQ. PQ, being the major active metabolite of BQ, might be responsible for the extended therapeutic effect of BQ. The oral bioavailability of BQ was 3.12%, 5.3% and 12% in rats, rabbits and monkeys, respectively, which could be mainly due to the high instability of BQ at acidic pH as demonstrated from a simulated gastric fluid stability study. Protein binding in various species was in the range 50-65% while the partition coefficient between RBCs and plasma (K(rbc/pl)) was between 0.75 and 1, indicating significant RBC uptake., (Copyright (c) 2007 John Wiley & Sons, Ltd.)

Lipomas are benign tumors, composed of fat cells of the adult type. While lipomas on the trunk and limbs are common, they are rare in the upper aerodigestive tract. Here we report a case of laryngeal lipoma presented with a complaint of change of voice.

Fungal infection of the larynx is a relatively uncommon condition. The lesions max be confined to the vocal folds or may involve various other sites in the larynx. There is, invariably, a risk factor that predisposes to fungal infection viz. immune deficiency, inhaled or systemic steroids, antibiotic usage, etc. These lesions may mimic malignancy or a premalignant condition. There have been very few cases of laryngeal thrush reported in the literature. Awareness of this entity is essential because the management depends on an accurate diagnosis. These lesions invariably respond to a course of oral antifungal therapy and correction of risk factors. We report 3 cases of laryngeal thrush.

Introduction: Centchroman (international nonproprietary name: ormeloxifene) is a nonsteroidal selective estrogen receptor modulator, oral contraceptive, anticancer and antiosteoporotic agent that is intended for long-term use by women. In view of the vast clinical applications and interactions of steroidal oral contraceptives with commonly used therapeutic agents, the interaction potential of certain concomitantly administered therapeutic agents was investigated in terms of postcoital contraceptive efficacy (pharmacological) and the pharmacokinetic profile of centchroman in female Sprague-Dawley rats. The coadministered drugs used in the study were ciprofloxacin, cefixime, amoxicillin, metronidazole, amlodipine, atenolol, theophylline, metformin, pioglitazone and glibenclamide., Materials and Methods: The pharmacological activity of centchroman was evaluated in sperm-positive female rats at 1.5 mg/kg, with or without coadministered drugs. Rats were sacrificed on Day 10 postcoitus, and autopsy was performed to check for the presence or absence of implantations. The estrogenic and antiestrogenic activities of centchroman were evaluated in immature ovariectomized rats. Pharmacokinetic interaction was studied in normal female rats with or without coadministered drugs. Serum samples were taken over 120 h and analyzed using a validated high-performance liquid chromatography method to generate the pharmacokinetic profile of centchroman. Pharmacokinetic parameters were estimated using noncompartmental analysis, and the results were compared., Results: In pharmacological interaction studies, centchroman alone showed a 100% success rate when given alone or in the presence of coadministered drugs. The only exception was amoxicillin coadministration, with 66% rats in the group showing resorbed implantations. Further investigation with amoxicillin in ovariectomized immature rats indicates no alteration in the estrogenic and antiestrogenic profiles of centchroman. In pharmacokinetic interaction studies, most of the therapeutic agents affected the rate and extent of absorption of centchroman. In other pharmacokinetic parameters, clearance (CL) remained unchanged; however, there was decrease in bioavailability (F) and volume of distribution (V(d)) in some situations., Conclusions: The results indicate that there is no direct link between the altered pharmacokinetics of centchroman and the failure of pharmacological effect. The pharmacological interaction with amoxicillin could not be explained on the basis of alteration in the estrogenic and antiestrogenic activities of centchroman, indicating that different mechanisms are involved. The findings, however, suggest that amoxicillin coadministration may result in pharmacological interaction with centchroman and that caution should be taken in clinical practice.

Cardiac troponin (cTn) is a key biomarker for the assessment of myocardial injury, but overutilization of this test has increased workload and costs. We developed and implemented an algorithm to eliminate excessive utilization. Significant reduction was observed after the implementation of the algorithm in total cTnI requests (29.9%; P = .007), requests from outpatient clinics (70.7%; P = .003), and other wards (42.8%; P = .003). Stat requests, the number of third requests, and more than 3 requests per patient were reduced significantly by 42.8% (P = .004), 35.8% (P = .003), and 49.4% (P = .008), respectively. The test and labor costs each were reduced by 29.9% (P = .007 for each). There was no significant change in cTnI orders from emergency and critical care departments. The cTnI testing algorithm reduced unnecessary orders for cTnI tests with no reduction in meeting patients'critical needs. Reduction in unnecessary and inappropriate requests reduces labor and test costs.

In an effort to generate more stable reaction intermediates involved in substrate oxidation by nitric-oxide synthases (NOSs), we have cloned, expressed, and characterized a thermostable NOS homolog from the thermophilic bacterium Geobacillus stearothermophilus (gsNOS). As expected, gsNOS forms nitric oxide (NO) from l-arginine via the stable intermediate N-hydroxy l-arginine (NOHA). The addition of oxygen to ferrous gsNOS results in long-lived heme-oxy complexes in the presence (Soret peak 427 nm) and absence (Soret peak 413 nm) of substrates l-arginine and NOHA. The substrate-induced red shift correlates with hydrogen bonding between substrate and heme-bound oxygen resulting in conversion to a ferric heme-superoxy species. In single turnover experiments with NOHA, NO forms only in the presence of H(4)B. The crystal structure of gsNOS at 3.2 AA of resolution reveals great similarity to other known bacterial NOS structures, with the exception of differences in the distal heme pocket, close to the oxygen binding site. In particular, a Lys-356 (Bacillus subtilis NOS) to Arg-365 (gsNOS) substitution alters the conformation of a conserved Asp carboxylate, resulting in movement of an Ile residue toward the heme. Thus, a more constrained heme pocket may slow ligand dissociation and increase the lifetime of heme-bound oxygen to seconds at 4 degrees C. Similarly, the ferric-heme NO complex is also stabilized in gsNOS. The slow kinetics of gsNOS offer promise for studying downstream intermediates involved in substrate oxidation.

Objective: The purpose of this series was to emphasize the varied presentations of midgut volvulus from neonatal life to well into adulthood and to evaluate the role of the whirlpool sign on sonography in diagnosing this condition., Methods: A retrospective search of all midgut volvulus cases diagnosed in the radiology department of a 1500-bed general hospital between February 2002 and July 2005 was done. Eight patients with surgically confirmed midgut volvulus were found, all of whom had undergone sonography as the initial screening investigation., Results: Eight patients, with ages ranging from 9 days to 32 years (mean age, 11.8 years), had undergone sonography for varied conditions, including bilious and nonbilious vomiting, vague abdominal pain, epigastric lumps, weight loss, features mimicking appendicitis, and pancreatitis. In all patients, the diagnosis of midgut volvulus was made on the basis of the clockwise whirlpool sign on sonography. Subsequently, 4 patients underwent upper gastrointestinal series, and contrast-enhanced computed tomography was done in 6 cases. Surgical confirmation of the diagnosis was obtained in all cases. Two patients were taken for surgery on the basis of only sonographic findings., Conclusions: Midgut volvulus can also appear much beyond the neonatal age group with a variety of clinical presentations, making the clinical diagnosis in such patients very difficult, if not impossible. Identification of the clockwise whirlpool sign on sonography is an accurate way of diagnosing this condition, which can preclude the need for further investigations and can allow prompt surgical intervention.

The present study was conducted to investigate the differences in the vitreous humor biochemical concentrations for vitreous electrolytes and calcium in the same pair of eyes at identical postmortem interval (PMI). The vitreous humor samples were collected independently in both eyes from 48 autopsies (PMI range, 4.5-84.3 hours) with documented time of death. The samples were analyzed for potassium, sodium, chloride, and calcium using a Beckman Coulter LX20 Automated Analyzer based on ion-selective electrode methodology. There were no statistically significant between-eye differences at identical postmortem interval. A significantly high correlation was observed between paired potassium concentrations of both the eyes. A highly significant linear correlation was observed between the individual eye and mean potassium concentrations of both the eyes with postmortem interval. The observed differences were not significantly correlated with postmortem interval. The results demonstrated that the between-eye differences for vitreous electrolytes and calcium are insignificant. Therefore, the utility of vitreous biochemistry, particularly potassium in postmortem interval estimation and other forensic applications, cannot be questioned solely on the basis of these differences.

Multichannel auditory brainstem implants (ABI) are currently indicated for patients with neurofibromatosis type II (NF2) involving both vestibulocochlear nerves. The ABI helps bypass the damaged cochlear nerves and restores a level of auditory sensation via the electrical stimulation of the cochlear nucleus. The implant is usually placed in the lateral recess of the fourth ventricle at the time of tumor resection to stimulate the cochlear nucleus. We report a case of ABI done on a 15-year-old girl with bilateral vestibular schwannomas.

The Institute of Medicine (IOM) report (1999) stated that the prevalence of medical errors is high in today's health care system. Some specialties in health care are more risky than others. A varying blunder/error rate of 0.1-9.3% in clinical diagnostic laboratories has been reported in the literature. Many of these errors occur in the preanalytical and postanalytical phases of testing. It has been suggested that the errors occurring in clinical diagnostic laboratories are smaller in number than those occurring elsewhere in a hospital setting. However, given the quantum of laboratory tests used in health care, even this small rate may reflect a large number of errors. The surgical specialties, emergency rooms, and intensive care units have been previously identified as areas of risk for patient safety. Though the nature of work in these specialties and their interdependence on clinical diagnostic laboratories presents abundant opportunities for error-generating behavior, many of these errors may be preventable. Appropriate attention to system factors involved in these errors and designing intelligent system approaches may help control and eliminate many of these errors in health care.

The issue of medical errors has received substantial attention in recent years. The Institute of Medicine (IOM) report released in 1999 has several implications for health care systems in all disciplines of medicine. Notwithstanding the plethora of available information on the subject, little, by way of substantive action, is done toward medical error reduction. A principal reason for this may be the stigma associated with medical errors. An educational program with a practical, informed, and longitudinal approach offers realistic solutions toward this end. Effective reporting systems need to be developed as a medium of learning from the errors and modifying behaviors appropriately. The presence of a strong leadership supported by organizational commitment is essential in driving these changes. A national, provincial or territorial quality care council dedicated solely for the purpose of enhancing patient safety and medical error reduction may be formed to oversee these efforts. The bioethical and emotional components associated with medical errors also deserve attention and focus.

The prevalence of medical errors in health care systems has generated immense interest in recent years. The research on adverse events in hospitalized populations has consistently revealed high rates of adverse events. Some of these adverse events result from medical errors and a majority of these errors may be preventable. These errors can occur anywhere and at anytime in health care processes. The consequences of these errors may vary from little or no harm to being ultimately fatal to the patients. It is important to recognize that a degree of error is inevitable in any human task and human fallibility in health care should be accepted. The underlying precursors for many of these human errors may primarily be attributed to latent systemic factors inherent in today's increasingly complex health care system. The focus of adverse event analyses on individual shortcomings without appropriate attention to system issues leads to ineffective solutions. The cognitive influence on medical decision-making and error generation is also significant and should not be discounted.

At present, the construction of chromatographic fingerprints of complex herbal preparations in combination with mass spectrometry plays an important role in their development and standardization as potential therapeutic agents. Picroliv, an extract from roots and rhizomes of Picrorhiza kurroa, is a herbal hepatoprotective developed by CDRI. We report for the first time pattern profiling of various constituents of picroliv along with a precise and accurate method to estimate relative concentration of major components in the preparation by liquid chromatography-tandem mass spectrometry. In total, 27 components could be detected in multiple reaction monitoring (MRM) mode out of which fourteen could be quantified in terms of their relative concentration. Seven components were structurally correlated and confirmed based on the fragmentation pattern and information available in literature. The detection was carried out using MRM in negative ionization mode with analytes quantified from the summed total ion value of their most intense molecular ion transitions. The separation of various components was achieved using a gradient elution on RP-18 column with acetonitrile and Milli-Q water as mobile phase at a flow rate of 1.0 ml/min. The method was validated in terms of linearity, accuracy and precision (within- and between-assay variation) for 5 days. Linearity range was different for various components depending upon their sensitivity and abundance in the herbal preparation. Within- and between-assay accuracy (%bias) and precision (%R.S.D.) were within acceptable limits. The method was successfully applied to detect and determine relative concentrations of various components in two different batches of picroliv.

CDRI 85/92, an anti-ulcer drug, is a new proton pump inhibitor, currently in an advanced stage of drug development. To know more about the drug it was our objective to delineate/identify the metabolic pathway as well as the enzymes responsible for the formation of metabolites. Metabolism of CDRI-85/92 (cis-5-styryl-2-oxazolidinone-4-carboxylic acid) was investigated in rat liver cellular fractions (S9, microsomes and cytosol) using reverse-phase HPLC and mass spectrometry techniques. Two major metabolites were produced by rat liver S9 fractions and reducing factor generating system from either untreated rats or phenobarbitone (PB)-pretreated rats. Incubation of CDRI-85/92 with postmitochondrial fraction (S9) for 24 h resulted in a cis to trans conversion (metabolite M2). Further cis-trans metabolizing capacity was measured separately in the cytosolic and microsomal fractions. Incubation with the cytosolic fraction resulted in an increased rate of cis-trans conversion, while the microsomal fraction showed no cis to trans conversion, thereby restricting the cis to trans conversion to Phase II enzymes, which are mainly located in the cytosol. Studies with PB-pretreated rat liver S9 fractions resulted in an increased rate of cis to trans conversion. Another metabolite was also present (M1) which was identified as an oxygenated metabolite by mass spectrometry. The major urinary metabolite from CDRI-85/92-treated Sprague-Dawley rats (20 mg/kg p.o.) was identified as M2. Studies using sulfobromophthalein and N-ethylmaleimide, as specific inhibitors of GST, showed a complete absence of metabolism, thus indicating the involvement of GST in the metabolism of CDRI-85/92. This study will be helpful in providing clues about factors influencing the bioavailability of CDRI-85/92 as well as drug-drug interactions.

A precise and reproducible HPLC assay has been developed and validated for simultaneous determination of bulaquine (BQ) and its metabolite primaquine (PQ) in rabbit plasma. The method, applicable to 0.5 ml plasma, involves double extraction of samples with n-hexane: isopropanol (98:2, v/v) containing dimethyl octylamine (DMOA) (0.1%, v/ v). Separations were accomplished by reversed-phase liquid chromatography using a Spheri-5 cyano column with a low pressure gradient with mobile phase consisting of ammonium acetate buffer (50 mM, pH 6.0) and acetonitrile with DMOA. The method was sensitive with a limit of quantitation of 20 ng ml(-1) in rabbit plasma for both BQ and PQ and the recoveries were > 85 and > 45%, respectively. Excellent linear relationships (r > 0.99) were obtained between the measured and added concentration ratios of the plasma concentrations over a range of 20-1000 ng ml(-1) for both the analytes. Precision and accuracy were acceptable as indicated by relative standard deviations from 1.8 to 15.1%, bias values ranging from -14.2 to 15.7%. Moreover, BQ was stable in rabbit plasma for 15 days of storage at -60 degrees C and after being subjected to three freeze-thaw cycles. The method was applied to determine the levels and pharmacokinetics of BQ in rabbits following a single 2.5 mg kg(-1) oral and intravenous dose. The BQ levels declined and the PQ levels increased with time. The PQ/BQ ratio after oral dose at 1 and 1.5 h were higher than that after intravenous dose. In the pilot preclinical pharmacokinetic study after a single 2.5 mg kg(-1) oral dose, BQ levels were determined up to 6 h (post-prandial) and 8 h (fasting). The plasma concentration versus time data were best fitted to a two-compartment open model with first-order absorption and elimination processes without lag time. The AUC(0-infinity) and the elimination t1/2 in fasted rabbit was higher than that in post-prandial rabbit indicating the effect of food on BQ pharmacokinetics.

Objectives: We aimed to investigate the effect of tetracycline coadministration, with and without lactic acid bacillus spores supplementation, on the pharmacokinetics of centchroman, a nonsteroidal oral contraceptive, in healthy female volunteers., Participants and Methods: The study was a single-centre, single-blinded, randomised, parallel treatment study in healthy female subjects of reproductive age randomised to two groups (11 subjects in each group). On day 1, subjects were given either a single oral dose of centchroman 30 mg with tetracycline 250 mg (group A) or a single dose of centchroman 30 mg, tetracycline 250 mg and one tablet containing 60 million lactic acid bacillus spores (group B). Tetracycline (250 mg three times daily) and lactic acid bacillus spores (one tablet three times daily) were continued for 3 days. Serial blood samples were collected and analysed by high performance liquid chromatography. The pharmacokinetic parameters were compared with the control data reported previously from this laboratory., Results: Coadministration of tetracycline yielded significantly higher maximum plasma concentrations (C(max)) [35%] and a shorter time to reach C(max) (t(max)) values for centchroman (42%) than those obtained in the control group of females (p < 0.05). Inclusion of lactic acid bacillus spores in the regimen resulted in similar effects with increased C(max) (47%) and area under the concentration-time curve from time zero to infinity (34%) of centchroman (p < 0.05) with a significant decrease in t(max). Other parameters such as half-life, apparent clearance, apparent volume of distribution and mean residence time of centchroman were not affected by either of the treatments., Conclusions: The apparent effects of either of the regimens on centchroman pharmacokinetics seem to be of little clinical relevance in terms of increased rate or extent of availability. It can be concluded that this tetracycline-containing regimen is unlikely to alter the contraceptive efficacy of centchroman in humans.

A high-performance liquid chromatographic (HPLC) method was developed for the analysis of N,N'-Dichlorobis (2,4,6-trichlorophenyl) urea (CC-2), a potent sulphur mustard decontaminant, in rat serum. The HPLC analysis, applicable to 0.5 ml volumes of serum, involved double extraction of serum samples with diethyl ether at alkaline pH followed by separation on a RP-18 column and the use of UV detector at 230 nm. The method was sensitive with a limit of quantitation of 10 ng ml(-1) in rat serum and the recovery was always >90%. Excellent linear relationships (r>0.99) were obtained between the measured and added concentration ratios of the serum concentrations over a range of 10-200 ng ml(-1). The precision and accuracy were acceptable as indicated by relative standard deviation ranging from 2.47 to 17.49%, bias values ranging from -4.35 to 13.21%. Moreover, CC-2 was found stable in rat serum even after 3 months of storage at -60 degrees C and being subjected to three freeze-thaw cycles. The assay was found to be sensitive, specific, accurate, precise, and reliable for use in pharmacokinetic studies.