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Biomedical subjects

B K Rath

Publications and source records attributed to B K Rath.

10 recordsLinked to original sources
PubMed2004

Randomized control trial of quinine and artesunate in complicated malaria.

OBJECTIVE: To study the comparative efficacy of the quinine and artesunate in complicated malaria in children. METHODS: All cases admitted to the Pediatrics ward of our hospital with clinical features of complicated malaria (WHO criteria) having asexual forms of P. falciparum in the peripheral smear, were included in the study. Relevant investigations were carried out for confirmation of diagnosis and to assess the prognosis. The patients were sub-grouped into 6 categories as per clinical presentations and each subgroup received alternatively either quinine or artesunate by systematic random sample method. Every odd number received quinine (Group-1) and every even number received artesunate (Group-2). 40 cases in each group were considered for the study and the data obtained were compiled and analyzed by suitable statistical tests. RESULTS: 80 children with complicated malaria enrolled in the present study, of which 48 were boys and 32 were girls. The mean age was 7.93+3.56 years. The most common presentations were fever, splenomegaly and altered sensorium. The CRT, FCT and PCT were significantly less in the artesunate group (50.4 +/- 31.49 hrs; 43.55 +/- 20.12 hrs, and 41.67 +/- 16.78 hrs respectively) as compared to the quinine group (70.15 +/- 17.56 hrs, 62.23 +/- 16.99 hrs, and 52.24 +/- 12.69 hrs respectively) ( p<0.05) No side effects were observed in the artesunate treated group. CONCLUSION: Artesunate is a much better drug than quinine in complicated malaria in terms of rapid coma resolution, fever clearance, parasite clearance and better tolerability.

Adolescent↗
PubMed2002

Electron tomography of frozen-hydrated isolated triad junctions.

Cryoelectron microscopy and tomography have been applied for the first time to isolated, frozen-hydrated skeletal muscle triad junctions (triads) and terminal cisternae (TC) vesicles derived from sarcoplasmic reticulum. Isolated triads were selected on the basis of their appearance as two spherical TC vesicles attached to opposite sides of a flattened vesicle derived from a transverse tubule (TT). Foot structures (ryanodine receptors) were resolved within the gap between the TC vesicles and TT vesicles, and some residual ordering of the receptors into arrays was apparent. Organized dense layers, apparently containing the calcium-binding protein calsequestrin, were found in the lumen of TC vesicles underlying the foot structures. The lamellar regions did not directly contact the sarcoplasmic reticulum membrane, thereby creating an approximately 5-nm-thick zone that potentially constitutes a subcompartment for achieving locally elevated [Ca(2+) ] in the immediate vicinity of the Ca(2+)-conducting ryanodine receptors. The lumen of the TT vesicles contained globular mass densities of unknown origin, some of which form cross-bridges that may be responsible for the flattened appearance of the transverse tubules when viewed in cross-section. The spatial relationships among the TT membrane, ryanodine receptors, and calsequestrin-containing assemblage are revealed under conditions that do not use dehydration, heavy-metal staining, or chemical fixation, thus exemplifying the potential of cryoelectron microscopy and tomography to reveal structural detail of complex subcellular structures.

Animals↗
PubMed1998

Electron microscopic tomography of rat-liver mitochondria and their interaction with the endoplasmic reticulum.

Electron microscopic tomography can provide a complete three-dimensional range of information about subcellular structures. Applied to mitochondria, it has shown that the conventional textbook model of this organelle is incorrect. The infoldings of the inner membrane (called cristae) are connected by narrow tubular regions to each other and to the outside, suggesting that internal diffusion of ions, metabolites and proteins may be restricted. Tomographic reconstruction of mitochondria in situ indicates these organelles may occur in clusters with stacks of endoplasmic reticulum, forming extended structures that may be involved in [Ca++] regulation.

Animals↗
PubMed1997

Low-dose automated electron tomography: a recent implementation.

Low-dose automated tomography has been implemented on a 400-kV JEOL intermediate voltage electron microscope. Instrumentation and procedures for automatic tomographic series data collection are described. Difficulties encountered and ways to overcome them are discussed. A low-dose tomographic projection series of a triad junction of frog sartorius muscle was semiautomatically collected and a 3-D reconstruction of this organelle was made.

Animals↗
PubMedDate not supplied

Fast 3D motif search of EM density maps using a locally normalized cross-correlation function.

Three-dimensional motif search is becoming increasingly important both in the search for molecular signatures within a tomographic reconstruction, at low resolution, and in the search for atomic structures within high-resolution cryo-EM maps of macromolecular complexes. The present work describes the implementation of a fast local correlation algorithm suitable for template matching in the SPIDER environment. Two examples are given, one in each of the areas of application: (i). within a 7.8A single-particle reconstruction of the Escherichia coli ribosome, four proteins and one RNA structure were located with high accuracy; (ii). within a cryo-tomogram of sarcoplasmic reticulum vesicles, ryanodine receptors were located in positions that agreed with expert knowledge.

Algorithms↗
PubMedDate not supplied

Fast automatic particle picking from cryo-electron micrographs using a locally normalized cross-correlation function: a case study.

Recent progress in single-particle reconstruction methods and cryo-EM techniques has led to the determination of macromolecular structures with unprecedented resolution. The number of particles that goes into the reconstruction is a key determinant in achieving high resolution. Interactive manual picking of particles from an electron micrograph is a very time-consuming, tedious, and inefficient process. We have implemented a fast automatic particle picking procedure in the SPIDER environment. The procedure makes use of template matching schemes and employs a recently developed locally normalized correlation algorithm based on Fourier techniques. As a test, we have used this procedure to pick 70S Escherichia coli ribosomes from a cryo-electron micrograph. Different search strategies including use of a circular mask and asymmetric masks for different orientations of the particle have been explored, and their relative efficiencies are discussed. The results indicate that the procedure can be optimally used to pick ribosomes in a fully automatic way within the limit of selecting less than 10% false positives while missing about 15% of true positives.

Algorithms↗