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Biomedical subjects

Ram Singh

Publications and source records attributed to Ram Singh.

At least 19 recordsLinked to original sources
PubMed2006

Remission of rheumatoid arthritis after acute disseminated varicella-zoster infection.

A 65-year-old immunocompetent male presented with symmetric polyarthritis of 12 weeks and paresthesias in the distribution of the left median nerve distribution of 4 weeks duration. He had tender joint count of 20 and swollen joint count of 12. He was positive for rheumatoid factor and his erythrocyte sedimentation rate was 52 mm. Nerve conduction study demonstrated polyneuropathy. Radiographs showed severe juxta articular osteopenia at the wrist and the metacarpophalangeal joints. He received methotrexate of 10 mg/week and prednisolone of 0.15 mg/kg/day along with nonsteroidal antiinflammatory drugs (NSAIDs) with a diagnosis of seropositive rheumatoid arthritis (RA). Thirteen weeks after therapy, he presented to the outpatient clinic with disseminated vesicular eruptions all over his body with erythematous base and pneumonia involving the left upper lobe. Tzanck smear from the lesions and serology (IgG) for varicella-virus infection were positive. A diagnosis of acute disseminated varicella zoster with pneumonia was made. The patient improved on parenteral acyclovir and broad-spectrum antibiotics. With the improvement in rash and pneumonia after 2 weeks, the patient noticed a marked improvement in the joint symptoms. Arthritis remained in remission without the need for any disease-modifying drug or NSAID for next the 24 months and continued to be so until the last follow-up. Our case presents a unique phenomenon of RA remission after disseminated varicella-zoster infection in an immunocompetent individual.

Aged↗
PubMed2006

Nitrilase and its application as a 'green' catalyst.

Hydrolase-catalyzed reactions have been widely applied in organic synthesis. Nitrilases are an important class of hydrolase that converts naturally occurring, as well as xenobiotically derived, nitriles to the corresponding carboxylic acids and ammonia. Because of their inherent enantio- and regioselectivities and other benefits, nitrilases are attractive as 'green', mild, and selective catalysts for setting stereogenic centers in fine-chemical synthesis and enantiospecific synthesis of a variety of carboxylic acid derivatives. In this review, the literature has been surveyed to provide a comprehensive coverage of the application of nitrilases in organic synthesis. Literature has also been cited to describe the isolation and/or characterization of nitrilases and related enzymes.

Aminohydrolases↗
PubMed2006

Fatal cerebral edema from late-onset ornithine transcarbamylase deficiency in a juvenile male patient receiving valproic acid.

OBJECTIVES: The aims of this report are to 1) present a rare case of fatal cerebral edema associated with late-onset ornithine transcarbamylase (OTC) deficiency in a juvenile male patient receiving valproic acid and 2) review the neuropathologic changes associated with the hyperammonemia. DESIGN: Case report. SETTING: A community hospital and a tertiary pediatric critical care unit. INTERVENTIONS: Carbohydrate administration, intravenous nitrogen excretion cocktail, and high-flux hemodialysis. MEASUREMENTS AND MAIN RESULTS: Despite aggressive therapy for presumed late-onset OTC deficiency, the patient rapidly developed fatal cerebral edema with tonsillar herniation. A liver biopsy confirmed OTC deficiency with approximately 3% of residual hepatic enzyme activity. Chromosomal analysis showed a normal male karyotype. A thorough molecular analysis of the coding region in the OTC gene Xp21.1 was completed, but mutations were not identified, suggesting an upstream or downstream abnormality. Severe brain swelling was evident on neuropathology, and histopathology showed Alzheimer type II astrocytes, neuronal cytoplasmic changes, and hypertrophy and eosinophilia of the small arterial walls. CONCLUSIONS: OTC deficiency is the most common urea cycle defect causing hyperammonemia. Late-onset presentations of OTC are infrequent, primarily affecting female patients. We present a rare case of a late-onset OTC deficiency in a juvenile male patient receiving valproic acid therapy who developed fatal cerebral edema. Valproic acid exacerbates acute elevations in ammonia and may contribute synergistically with ammonia to cerebral mitochondrial dysfunction.

Adolescent↗
PubMed2006

Transcriptional response to the neuroleptic-like compound Ampullosporin A in the rat ketamine model.

Psychotic disorders affecting up to 1% of the human population represent pathological changes to the metabolic homeostasis of the brain. Increasing evidence in the literature suggests complex biochemical and/or transcriptional alterations accompanying schizophrenia-like phenomena. Sub-chronic treatment with sub-anaesthetic doses of ketamine induces schizophrenia-related psychotic alterations that can be used as an animal model in the study of this disorder. Ampullosporin A belongs to a specific group of pore-forming fungal peptides, peptaibols. We focused on the analysis of molecular events occurring in the brain of ketamine-pre-treated rats after administration of Ampullosporin A with neuroleptic-like activity. The complex experimental approach allowed us to correlate the use of low molecular weight substances with a transcriptome fingerprint in the prefrontal cortex. We found 63 genes to be up-regulated and 22 genes suppressed, with transthyretin, syndecan-1 and NeuroD1 showing the highest degree of up-regulation. Our results suggest the possibility that Ampullosporin A belongs to the group of neuroleptic-like compounds, inducing massive changes in neurotransmitter receptor composition, calcium signalling cascades and second messenger systems, and leading to the plastic reorganization of brain tissue, metabolic pathways and synapses.

Animals↗
PubMed2006

Influence of cytoplasmic male sterility on expression of different mechanisms of resistance in sorghum to Atherigona soccata (Diptera: Muscidae).

Atherigona soccata (Rondani) (Diptera: Muscidae) is one of the most important pests of sorghum, Sorghum bicolor (L.) Moench, in Asia, Africa, and the Mediterranean Europe. Exploitation of cytoplasmic male sterility (CMS) for hybrid production has resulted in considerable narrowing of the genetic base and may increase the vulnerability of this crop to insect pests. Therefore, we studied the expression of different mechanisms of resistance in sorghum to A. soccata in CMS (A) and maintainer (B) lines of 12 genotypes under field and greenhouse conditions. The CMS lines of A. soccata-resistant genotypes were preferred for oviposition (78.5 versus 71.5% plants with eggs) and suffered greater deadheart incidence (47.6 versus 41.6%) than the corresponding maintainer lines, whereas such differences were not apparent in CMS lines belonging to the susceptible genotypes (92.7 versus 92.3% plants with eggs and 75.6 versus 74.6% deadhearts) under multichoice field conditions. Similar differences also were observed under controlled conditions in the greenhouse. The larval period (9.0 versus 8.8 d) and pupal mortality (18.4 versus 13.4%) were greater on maintainer lines than that on the CMS lines in the resistant group. The male and female pupal weights, fecundity, and antibiosis index were greater on the CMS than on the maintainer lines. The maintainer lines showed better recovery resistance than the CMS lines, but no such differences were observed in tiller deadhearts. The differences in susceptibility to A. soccata were greater in the A. soccata resistant CMS and maintainer lines than in the CMS and maintainer lines belonging to susceptible genotypes. Conversion of A. soccata-resistant genotypes into alternate less susceptible cytoplasmic backgrounds may be undertaken for developing sorghum hybrids with stable resistance to A. soccata.

Animals↗
PubMed2006

Accidental poisoning due to motor vehicle exhaust.

Motor vehicle exhaust contains a mixture of poisonous gases mainly the carbon monoxide. Exposure to this exhaust can be lethal in a closed space. One such case occurring in a young male is described.

Adult↗
PubMed2005

The melon fruit fly, Bactrocera cucurbitae: a review of its biology and management.

The melon fruit fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae) is distributed widely in temperate, tropical, and sub-tropical regions of the world. It has been reported to damage 81 host plants and is a major pest of cucurbitaceous vegetables, particularly the bitter gourd (Momordica charantia), muskmelon (Cucumis melo), snap melon (C. melo var. momordica), and snake gourd (Trichosanthes anguina). The extent of losses vary between 30 to 100%, depending on the cucurbit species and the season. Its abundance increases when the temperatures fall below 32 degrees C, and the relative humidity ranges between 60 to 70%. It prefers to infest young, green, soft-skinned fruits. It inserts the eggs 2 to 4 mm deep in the fruit tissues, and the maggots feed inside the fruit. Pupation occurs in the soil at 0.5 to 15 cm below the soil surface. Keeping in view the importance of the pest and crop, melon fruit fly management could be done using local area management and wide area management. The melon fruit fly can successfully be managed over a local area by bagging fruits, field sanitation, protein baits, cue-lure traps, growing fruit fly-resistant genotypes, augmentation of biocontrol agents, and soft insecticides. The wide area management program involves the coordination of different characteristics of an insect eradication program (including local area options) over an entire area within a defensible perimeter, and subsequently protected against reinvasion by quarantine controls. Although, the sterile insect technique has been successfully used in wide area approaches, this approach needs to use more sophisticated and powerful technologies in eradication programs such as insect transgenesis and geographical information systems, which could be deployed over a wide area. Various other options for the management of fruit fly are also discussed in relation to their bio-efficacy and economics for effective management of this pest.

Animals↗
PubMed2005

Remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome: ultrasonography as a diagnostic tool.

Remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome is characterized by symmetrical synovitis and swelling of both the upper and lower extremities. The anatomical determinant of RS3PE is predominantly extensor tenosynovitis as revealed by magnetic resonance imaging (MRI). Given the cost constraints, time, and expertise required in carrying out MRI and ease in diagnosing tenosynovitis by ultrasound, we utilized high-frequency ultrasonography (USG) for evidence of tenosynovitis of the distal tendons in patients with RS3PE. Diagnosis of tenosynovitis was made on the basis of anechoic or hypoechoic signals around the tendon sheaths in both transverse and longitudinal planes. Flexor and extensor tendons at the wrist and metacarpal heads and extensor digitorum longus (EDL) tendons at the ankle were evaluated with a 7.5-10-MHz linear probe. There were ten patients (seven males) with a mean age of 59.5 years (range: 52-78 years) and mean disease duration of 6.1 months (range: 1.5-12 months). Disease onset was acute in all of the cases. Pitting edema of the hands was present in all except two patients whereas four patients, in addition, had edema of the feet. Edema was symmetrical in seven patients. Inability to make a complete fist was noted in all. Tenosynovitis of extensor and flexor tendons at the wrist and the metacarpal heads was documented in all patients with edema of the hands. In seven cases extensor tendon tenosynovitis was more prominent compared to the flexor tendons. Tenosynovitis of EDL tendons was detected in six cases. Dramatic relief with low-dose prednisolone was noted in all patients within 6 weeks of therapy. At a mean follow-up of 10.1 months all patients had marked relief in edema of extremities and improvement in the grip strength. Our study confirms that tenosynovitis of both flexor and extensor tendons at the wrist and extensor tendons of the feet is the hallmark of RS3PE syndrome. USG is a reliable and cost-effective modality for evaluation of patients with suspected RS3PE.

Aged↗
PubMed2005

Exploring the mechanisms of molecular recognition by flavins.

The design and development of chemical models for enzymes depends on the fundamental principles observed in biological systems. Molecular recognition of flavins by various receptors has attracted attention due to their applications as chemical models for flavoenzymes. The area of molecular recognition is being investigated through research at the interface of chemistry and biology. In this review, the literature has been surveyed to provide comprehensive coverage of the synthetic methodology of different flavins and receptors and their molecular-recognition studies. Various applications of flavin-receptor complexes have also been highlighted.

Flavins↗
PubMed2004

9,10-Anthraquinones and other biologically active compounds from the genus Rubia.

The secondary metabolites isolated from Rubia species, their biological activities, and colouration properties have been reviewed. Over 150 chemical constituents belonging to different classes of bioactive compounds such as anthraquinones and their glycosides, naphthoquinones and glycosides, terpenes, bicyclic hexapeptides, iridoids, and carbohydrates are listed together with their source(s) and corresponding references.

Anthraquinones↗
PubMed2004

Electron transfer in natural and unnatural flavoporphyrins.

The development of chemical models for enzymes and their chemical and physical studies constitutes an important area of research from a scientific as well as an industrial point of view. Covalently linked flavin and porphyrin (flavoporphyrins) have attracted attention due to their applications as chemical models for flavoproteins and related enzymes. In this review, the literature has been surveyed to provide a comprehensive coverage of the synthetic methodology and characterization techniques of various types of synthetic flavoporphyrins.

Amides↗
PubMed2004

Pediatric trauma in southwestern Ontario: linking data with injury prevention initiatives.

BACKGROUND: Our objective was to provide an epidemiologic description of pediatric trauma in SW Ontario using multiple data sets. Injury prevention (IP) initiatives were linked with predominant injury mechanisms to determine whether IP programs were supported by data. METHODS: Descriptive analysis was undertaken for five pediatric age groups (<1 year, 1-4 years, 5-9 years, 10-14 years, 15-19 years) using the Ontario Trauma Registry's Death Data Set, Comprehensive Data Set (Lead Trauma Hospitals [LTH] patients), and Minimal Data Set (hospital admissions), 1999-2000, for all pediatric patients residing in SW Ontario. National Ambulatory Care Reporting System (NACRS) data from the Children's Hospital of Western Ontario/London Health Sciences Centre were used to capture the Emergency Room (ER) injury data. Information on IP initiatives for children and youth was gathered through an Internet search, supplemented by a survey. RESULTS: Injury in SW Ontario resulted in 13,197 ER visits, 1,616 hospital admissions, 70 severe trauma (ISS > 12) cases treated at a LTH and 47 deaths to children and youth. More males than females were injured, with the sex differential more pronounced as age increased. Falls were the leading mechanism for ER visits (37%) and hospital admissions (26%). Recreational injuries represented approximately 30% of injuries to the 10-14 yr age group. As ISS increased, MVCs emerged as an important mechanism, representing 71% of LTH cases and 53% of pediatric injury deaths in SW Ontario. There were 61 pediatric IP programs identified in SW Ontario. Eighty-four percent of programs (51/61) were supported by data, and were related to one of the predominant injury mechanisms. CONCLUSIONS: Injury is a serious problem for children in SW Ontario. Data can be used to identify modifiable risk factors to develop and implement new IP initiatives with the goal of reducing childhood injury and death. There is a need to integrate and link IP programs in SW Ontario for full coverage of all injury mechanisms.

Accident Prevention↗
PubMed2004

Isolated nocardial subcapsular and perinephric abscess.

We report a rare presentation of Nocardia infection in a 60 years old diabetic and cirrhotic patient who had perinephric and subcapsular renal abscess. This localized type of infection was successfully treated with oral cotrimoxazole.

Abscess↗
PubMed2003

Cerebral fat embolism as a rare possible complication of traumatic pancreatitis.

CONTEXT: Neurological complications following an acute attack of pancreatitis have been described. They are mainly in the form of encephalopathy, retinopathy and rarely polyneuropathy. Cerebral infarction following an acute attack of pancreatitis is very rare. CASE REPORT: We report the case of a 25 year old male, who developed multiple cerebral infarcts (both hemorrhagic and non-hemorrhagic) as a complication of acute pancreatitis. CONCLUSION: This is probably the first case report where a cerebral fat embolism during the course of acute pancreatitis has been hypothesized as a cause of cerebral infarction leading to hemiplegia.

Acute Disease↗
PubMed2002

Severe angioedema induced by angiotensin converting enzyme inhibitors: role of precipitating factors.

Angiotensin converting enzyme inhibitors like captopril, enalapril, lisinopril, trandopril and ramipril may rarely induce a life threatening angioedema. We present two cases of severe angioedema induced by enalapril and ramipril along with possible precipitating factors observed in these patients. The importance of prompt recognition and early management of such cases is emphasized.

Aged↗