Biomedical subjects
Publications and source records attributed to K Nagarajan.
INTRODUCTION: Canavan disease is a megalencephalic leukodystrophy due to deficiency of the enzyme aspartoacylase. Proton MR spectroscopy finding of elevated N-acetyl-L: -aspartate is considered diagnostic of Canavan disease. CASE REPORT: We report a case of Canavan disease, which showed restricted diffusion in diffusion-weighted imaging and discuss the cause of it.
BACKGROUND AND AIMS: Tuberculous meningitis (TBM) is a debilitating form of CNS tuberculosis with a high morbidity and mortality in spite of treatment. The diagnosis is based on clinical, radiological and laboratory features. The classical CT features of basal exudates, hydrocephalus, infarcts and granulomas have been mostly reported in younger individuals. Our aim was to study imaging features of TB meningitis in adults over the age of 50 years. MATERIALS AND METHODS: Clinical, imaging and laboratory features of 53 adult patients over the age of 50 years (sixth to eighth decades) were studied retrospectively. Diagnosis of TBM was based on clinical and laboratory features. RESULTS: Imaging features were the conspicuous absence of typical features of TBM (ie, basal meningeal enhancement, hydrocephalus, infarcts/granulomas were seen in only a minority of patients). CONCLUSIONS: CT features of TBM in elderly patients were few, atypical and non-contributory for diagnosis, probably because of age related immune senescence. Strong clinical suspicion and correlation with laboratory findings is necessary for early diagnosis.
Abscesses involving the cavum septum pellucidum are rare and, owing to their location, detection may be difficult with routine conventional computed tomography (CT). Only a few isolated cases have been reported and mostly in children. We report a case of abscess involving the cavum septum pellucidum in an adult and its appearance on multi-slice spiral CT.
The crystal structures of 1-(4-fluorophenyl)-2-phenyl-4,5,6,7-tetrahydro-1H-indole, C20H18FN, and 1-(4-fluorophenyl)-6,6-dimethyl-2-phenyl-4,5,6,7-tetrahydro-1H-indole, C22H22FN, have been determined in order to study the role of 'organic fluorine' in crystal engineering. These molecules pack in the crystal structure via different types of molecular motifs utilizing weak C-H...F and C-H...pi interactions.
The crystal and molecular structures of the three 4-ketotetrahydroindoles 2-(4-chlorophenyl)-1-(4-fluorophenyl)-6,6-dimethyl-4,5,6,7-tetrahydro-1H-indol-4-one (C22H19ClFNO), (I), 1-(4-fluorophenyl)-2-(4-methoxyphenyl)-6,6-dimethyl-4,5,6,7-tetrahydro-1H-indol-4-one (C23H22FNO2), (II), and 6,6-dimethyl-1,2-diphenyl-4,5,6,7-tetrahydro-1H-indol-4-one (C22H21NO), (III), have been determined via single-crystal X-ray diffraction in order to study the intermolecular interactions therein. All three structures are stabilized via intermolecular C-H...O and C-H...pi interactions, generating different molecular motifs.
pH dependent reactivity differences of dimethylsulfite towards the title complex 1 demonstrate the crucial need of oxo-anionic coordination of sulfite to the molybdenum centre of 1 in the model reductive half reaction of sulfite oxidase.
A two-channel FM biopotential recording system fabricated on a foldable, lightweight, polyimide substrate is presented. Each channel consists of a biopotential amplifier followed by a Colpitts oscillator with operating frequency tunable in the 88-108 MHz commercial FM band. The overall system measures 10 mm X 10 mm X 3 mm, weighs 0.74 g, uses two 1.5-V batteries, dissipates about 2 mW, and has a transmission range of 2 m. Using this system, electromyogram signals have been recorded from the dorsal ventral muscle and the dorsal longitudinal muscle of a giant sphinx moth (manduca sexta).
The title compound (C17H25NO3) is a perhydroindoleacetic acid which exhibits hypoglycemic activity. The cyclohexyl ring adopts a sofa conformation. The molecule contains an intramolecular O-H...O hydrogen bond.
Nimesulide 1 is a novel nonsteroidal antiinflammatory drug which inhibits the enzyme cyclooxygenase 2 (COX-2) more selectively than cyclooxygenase 1 (COX-1). Molecular modelling studies have been carried out on complexes of 1 with COX-1 and with mutants of COX-1 simulating COX-2. These indicate that the mutations I523V and S516A largely contribute to the selectivity. A comparative study with SC-558 2 has also been performed.
We prospectively studied the efficacy of peribulbar anesthesia in 76 consecutive patients who underwent vitreoretinal surgery. The mean duration of anesthesia was 124.74 +/- 50.17 minutes, and the mean duration of akinesia, 151.5 +/- 54.45 minutes. Adequate anesthesia and akinesia, independent of the duration of surgery, was obtained in 26 of 33 (78.8%) patients who underwent vitrectomy; 9 of 32 (28.1%) who underwent scleral buckling; and 2 of 11 (18.2%) who underwent vitrectomy combined with scleral buckling. In all, topical and systemic supplementation of drugs for inadequate anesthesia or akinesia allowed 32 of the 33 (97%) vitrectomies, 30 of the 32 (94%) scleral buckling procedures, and all 11 of the combined surgeries to be completed as planned. Three (4%) patients vomited, moved, or were restless, resulting in an operative complication or postponement of surgery. Fifty-eight (76%) said they would desire similar anesthesia if subsequent surgery was needed in the same or fellow eye. We conclude that peribulbar anesthesia should be considered primarily for patients requiring vitreous surgery alone, and as an alternative for patients requiring scleral buckling or combined surgery for whom general anesthesia is contraindicated.
A large number of nitroimidazoles have been examined for in vitro activity against three anaerobes - Bacteroides fragilis (Bf), a strain of Bf resistant to metronidazole (16a) and Clostridium perfringens and many found to be active. Among these may be mentioned 1-methyl-5-nitroimidazoles carrying N - bound hetetocycles at position 2, such as satranidazole 1a, 1b, 1c, 1k, 1n and 1v which are at least twice as active as metronidazole (16a), ornidazole (16b) and tinidazole (16c). Even more active are 5-nitroimidazolyl benzimidazole 5d, -thiazolidinone 6b and thiadiazolidine dioxide 8a. Many other types of compounds derived from 1-methyl-2-amino-5-nitroimidazole are feebly active. Among 5-nitroimidazoles with a carbon substituent at position 2, 16a, 16b and 16c are equiactive while dimetridazole 14f is more active than 16a against Bf. Some 2-vinyl derivatives are very potent, with 18f and 18i being outstanding. Activity better than that of metronidazole is seen for nitroimidazooxazepines, e.g. 29d. 5-Nitroimidazoles are more active against anaerobes than 4-nitro isomers. Antianaerobic and antiamoebic activities generally run parallel in these classes of compounds. The study has led to the elaboration of the antianaerobic profile of satranidazole 1a.
Condensation of beta-acetyl-2-hydroxy-4,4-dimethyl-6-oxo-1-cyclohexene-1-propionic acid (3) with n-butyl and isobutylamines affords the title acids 4 and 5, respectively, which show good oral hypoglycemic activity in normal rats. Acids 4 and 5, are also active in streptozocin-induced diabetic rats. Results of extensive pharmacological and acute toxicity tests are reported.
The frozen-section Ca45 uptake procedure of Mabuchi and Sreter has been applied to 51 frozen human muscle biopsies previously tested for halothane and for caffeine contracture responses. In preliminary tests with cat muscle, uptake varied with skeletal muscle fiber type, was absent from smooth muscle, and was blocked by agents which damage or extract sarcoplasmic reticulum. In the human biopsies, however, the calcium uptake values showed no significant correlation with any of the following parameters: time of frozen-biopsy storage up to 5 yr; fiber type distribution; positive versus negative response in the halothane contracture test; positive versus negative response in the caffeine contracture test; positive versus negative response in the combined halothane/caffeine contracture test; and presence of a documented clinical episode of malignant hyperthermia. In contrast, a positive halothane or caffeine contracture test each correlated highly with the presence of a prior clinical episode. We conclude that the evidence fails to support the use of the Ca45 uptake procedure in frozen sections of skeletal muscle biopsies as a valid indicator of malignant hyperthermia susceptibility.
4-hour in vitro growth curves of a type III group B streptococcus (GBS) and Escherichia coli were examined in sterile term human amniotic fluid specimens. Both bacterial strains proliferated despite ratios of phosphate to elemental zinc in the range reportedly inhibitory for E. coli. After 4 h of incubation, despite comparable inocula, GBS numbers exceeded those of E. coli by 10-fold. The strikingly rapid growth of some GBS strains in amniotic fluid may represent yet another factor responsible for perinatal GBS infection of the human neonate.
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In the present study the comparative in-vitro and in-vivo efficacy of Go 10213 was compared with those of metronidazole, secnidazole, tinidazole, ornidazole and nimorazole against a metronidazole-resistant strain of T. vaginalis. Go 10213 was found to be superior in activity. It appears more promising than the drugs mentioned above on the basis of the evidence presented.
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CG 10213-Go, a 5-nitroimidazole derivative synthesized at the CIBA-Geigy Research Centre, Bombay, proved superior to such currently used 5-nitroimidazole derivatives as metronidazole, ornidazole, secnidazole, tinidazole and nimorazole, against experimental amoebic infections of the liver and caecum in a golden hamster model. CG 10213-Go is now undergoing clinical trials.