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Biomedical subjects

G Suresh

Publications and source records attributed to G Suresh.

At least 19 recordsLinked to original sources
PubMed2005

The isomeric compounds nimbolide and isonimbolide.

Nimbolide [systematic name: (4alpha,5alpha,6alpha,7alpha,15beta,17alpha)-7,15:21,23-diepoxy-6-hydroxy-4,8-dimethyl-1-oxo-18,24-dinor-11,12-secochola-2,13,20,22-tetraene-4,11-dicarboxylic acid gamma-lactone methyl ester], C27H30O7, was isolated from the leaves of Azadirachta indica, and its isomer, isonimbolide [systematic name: (4alpha,5alpha,6alpha,7alpha,15alpha)-7,15:21,23-diepoxy-6-hydroxy-4,8-dimethyl-1-oxo-18,24-dinor-11,12-secochola-2,16,20,22-tetraene-4,11-dicarboxylic acid gamma-lactone methyl ester], was prepared from a novel rearrangement reaction of nimbolide, using boron trifluoride etherate and tetrabutylammonium bromide. The reaction conditions are probably responsible for the ether cleavage, double-bond rearrangement and reformation of the ether linkage. As a result, there are conformational changes in two cyclopentane rings and the side-chain -CH2COOMe group. In isonimbolide, an R(4)(4)(24) hydrogen-bond motif is observed.

Azadirachta↗
PubMed2005

Isolated intraperitoneal bladder rupture following minor trauma after alcohol ingestion.

The authors describe a case of intraperitoneal bladder rupture in a 41-year-old male caused by trauma from a fall after alcohol ingestion. The patient presented on the day following the fall with signs of acute urinary retention, and 500 mL of urine was drained after catheterization. Signs of peritonitis appeared on the following day, and emergency computed tomography revealed intraperitoneal rupture. Laparotomy revealed a laceration of the bladder in the fundus.

Accidental Falls↗
PubMed2004

Electrochemical study of potassium isobutyl xanthate at a mercury electrode.

Polarographic studies of potassium isobutyl xanthate at a mercury electrode reveal that the product of an anodic reaction is strongly adsorbed at the mercury surface, as indicated by a prewave. The adsorbed film greatly affects the characteristics of the anodic wave of xanthate in an aqeous medium. The current of total wave is proportional to the concentration of xanthate from 0.32 to 1.6 mM.

Journal Article↗
PubMed2003

Samaderin B and C from Samadera indica.

Samaderin B, or (1R,2S,5R,5aR,7aS,11S,11aS,11bR,14S)-1,7,7a,11,11a,11b-hexahydro-1,11-dihydroxy-8,11a,14-trimethyl-2H-5a,2,5-(methanoxymetheno)naphth[1,2-d]oxepine-4,6,10(5H)-trione, C(19)H(22)O(7), and samaderin C, or (1R,2S,5R,5aR,7aS,10S,11S,11aS,11bR,14S)-7,7a,10,11,11a,11b-hexahydro-1,10,11-trihydroxy-8,11a,14-trimethyl-2H-5a,2,5-(methanoxymetheno)naphth[1,2-d]oxepine-4,6(1H,5H)-dione, C(19)H(24)O(7), were isolated from the seed kernels of Samadera indica and were shown to exhibit antifeedant activity against Spodoptera litura third-instar larvae. The replacement of the carbonyl group in samaderin B by a hydroxy group in samaderin C causes conformational changes at the substitution site, but the overall conformation is not affected; however, the compounds pack differently in the crystal lattice.

Crystallography, X-Ray↗
PubMed2002

Azadirachtol, a tetranortriterpenoid from neem kernels.

The title compound, dimethyl (-)-(2aR,3R,4R,4aS,5R,7aS,8R,10S,10aR)-3,8,10-trihydroxy-4-[(2R,6R)-2-hydroxy-11-methyl-5,7,10-trioxatetracyclo[6.3.1.0(2,6)0(9,11)]dodec-3-en-9-yl]-4-methylperhydroisobenzofurano[5,4,3a-cd]isobenzofuran-5,10a-diacetate, C(28)H(36)O(13), which exhibits higher antifeedant activity than azadirachtin-A, a known potent antifeedant, was isolated from neem kernels. The asymmetric unit of the structure contains two independent molecules, which differ in the conformations of their functional groups and also in the conformations of some of the rings. The relative orientation between the decalin and furanyl moieties is similar to that observed in the majority of azadirachtin structures, but is different from that in azadirachtin-A. The two symmetry-independent molecules are linked into dimeric units by intermolecular O-H.O hydrogen bonds.

Azadirachta↗
PubMed2002

2',3'-Dehydrosalannol.

The title compound, methyl (2aS,3R,5R,5aS,6S,6aS,8R,9aS,10aR,10bR,10cS)-8-(3-furyl)-2a,4,5,5a,6,6a,8,9,9a,10a,10b,10c-dodecahydro-3-hydroxy-2a,5a,6a,7-tetramethyl-5-(3-methylbut-2-enoyloxy)-2H,3H-cyclopenta[4',5']furo[2',3':6,5]benzo[cd]isobenzofuran-6-acetate, C(32)H(42)O(8), was isolated from uncrushed green leaves of Azadirachta indica A. Juss (neem) and has been found to possess antifeedant activity against Spodptera litura. The conformations of the functional groups are similar to those of 3-desacetylsalannin, which was isolated from neem kernels. The molecules are linked into chains by intermolecular O-H.O hydrogen bonds.

Journal Article↗
PubMed2002

Insect antifeedant activity of tetranortriterpenoids from the Rutales. A perusal of structural relations.

Structure-related insect antifeedant relationship of 56 limonoids (both natural and modified) from the plants belonging to the order Rutales was attempted considering substitution patterns, oxidation states, and hydrophobicity, as well as distant geometry derived through conformational analysis on molecular modeling. Orientation of the furan and hydroxylation at specific carbon sites have been shown to influence the antifeedancy against the fall armyworm, Spodoptera litura.

Animals↗
PubMed2002

Review of augmentation 'clam' cystoplasy in a district general hospital setting.

Eighteen patients underwent augmentation 'clam' cystoplasty over a three-year period. All patients had urodynamic proven detrusor instability, which was refractory to conservative management. Fifteen of the patients are dry and appliance free. We performed more operations than have been reported in previous studies from other hospitals serving a similar population. Clam cystoplasty is an operation with an excellent outcome, which should be offered to patients with detrusor instability refractory to conservative management.

Adult↗
PubMed2001

Neurodegeneration in Niemann-Pick type C disease mice.

Niemann-Pick disease type C (NP-C) is an inherited neurodegenerative disorder associated with intracellular cholesterol and glycolipid trafficking defects. Two separate genes, NPC1 and NPC2, have been linked to NP-C. NPC1 encodes a polytopic membrane-bound protein with a putative sterol-sensing domain. NPC2 has been recently identified as epididymal secretory glycoprotein 1. The NPC1 protein functions in the vesicular redistribution of endocytosed lysosomal cargo, but how its inactivation leads to neurodegeneration is not known. The neurological symptoms of NP-C typically appear after a period of normal early development and reflect progressive degeneration of widespread brain regions. Here we have delineated the pattern of neurodegeneration in NP-C mice, whose genetic defect has been shown to be an inactivating mutation of the mouse NPC1 gene. The results reveal a spatially and temporally specific pattern of degeneration of nerve fibers followed by degeneration of neuronal cell bodies beginning as early as day 9 and continuing throughout life. We have recently showed that in the primate brain, the NPC1 protein is localized predominantly within perisynaptic astrocytic processes. The present observations suggest that a functional disturbance in NPC1 could disrupt vesicular transport of cholesterol, glycolipids and possibly other endocytic cargo in glia, which is critical for maintaining the integrity of neurons.

Aging↗
PubMed2001

Insect antifeedant and growth regulating activities of quassinoids from Samadera indica.

Four quassinoids, indaquassin C (1), samaderins C (2), B (3) and A (4), isolated from the seeds and bark of Samadera indica, were tested for insect antifeedant and growth regulatory activities against the tobacco cutworm, Spodoptera litura. Indaquassin C was the most effective antifeedant. Samaderin C increased pupal duration and induced pupal mortality.

Animals↗
PubMed2001

Video-EEG in the diagnosis of paroxysmal events in children with mental retardation and in children with normal intelligence.

Video-EEG monitoring was performed to evaluate 193 children (91 females, 102 males; mean age 9.6 years, SD 5.7) who presented with paroxysmal events of uncertain etiology. Diagnosis of the type of event, i.e. epileptic or non-epileptic, was successfully established in 130 of 193 patients (67.3%). Seventy children (36%) had mental retardation* (MR). Children with MR were more likely (p<0.05) than children without MR to have events during the studies. Children with and without MR had strikingly similar frequencies of epileptic and non-epileptic events. In participants who had events recorded and characterized, epileptic seizures were identified in 67 children (51.5%), non-epileptic events in 54 children (41.5%), and both epileptic and non-epileptic events in nine children (7%). Improved diagnosis prompted appropriate management. This should encourage more frequent use of video-EEG in children, especially in those with MR, to differentiate epilepsy from behavioral disturbances so that specific treatment can be provided.

Adolescent↗
PubMed2000

Antifungal activity of some tetranortriterpenoids.

Natural tetranortriterpenoids such as cedrelone from Toona ciliata, azadiradione from Azadirachta indica, limonin, limonol and nomilinic acid from Citrus medica, along with some cedrelone derivatives were tested for their antifungal activity against Puccinia arachidis, a groundnut rust pathogen. Results show that cedrelone was the most effective in reducing rust pustule emergence. Replacement of functional groups or modification of the A or the B ring in cedrelone reduced the effectiveness indicating the importance of specific structural features for activity.

Antifungal Agents↗
PubMed1998

Repeated isolation stress in the neonatal rat: relation to brain dopamine systems in the 10-day-old rat.

Isolation of the rat pup from the nest and dam for one hour per day from PN 2-9 is a useful paradigm for producing stress in the neonate. These previously isolated rats respond to an amphetamine challenge with alterations in activity at the juvenile stage or as adults. Furthermore, when dopamine release is measured in the nucleus accumbens, juveniles release 3 times more dopamine after amphetamine than do controls. This study describes changes in behavior and brain dopamine systems at PN 10. Experiment 1 determined an appropriate amphetamine dose that could be used for behavioral activation at PN 10. Experiment 2 produced significant evidence of enhanced behavioral activation after the isolation paradigm and indicated that brain regions innervated by the mesolimbic dopamine system, septum, and hypothalamus display increased dopamine turnover and that the nigrostriatal pathway is less active. Likewise, in Experiment 3, in vivo microdialysis of the nucleus accumbens indicated that previously isolated pups respond to an amphetamine challenge with a several-fold increase in dopamine release over a 4-hour session.

Animals↗