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Biomedical subjects

G N Reddy

Publications and source records attributed to G N Reddy.

At least 19 recordsLinked to original sources
PubMed2003

Development and validation of a liquid chromatographic method for monitoring of process-related synthetic organic impurities of profenofos in technical products.

A simple and rapid reversed-phase high-performance liquid chromatographic method for the monitoring of process-related synthetic organic impurities of profenofos (PFS) is developed. Impurities are separated and determined on a reversed-phase Hypersil C(18) column using gradient elution of 50 mM ammonium formate buffer-acetonitrile as a mobile phase and detection at 230 nm at ambient temperature. The method is validated with respect to accuracy, precision, linearity, and limits of detection and quantitation. The method is found to be suitable not only for monitoring the reactions involved in the process development of PFS, but also quality assurance, as it can detect impurities at the level of 1.5 x 10(-8) g.

Chromatography, High Pressure Liquid↗
PubMed1997

Massive osteolysis of the skull and upper cervical spine. Case report and review of the literature.

Massive osteolysis is a type of idiopathic osteolysis in which there is spontaneous onset of bone resorption. Almost any bone in the body can be affected. The authors present the case of a 62-year-old man diagnosed with massive osteolysis of the occipital bone and the upper two cervical vertebrae. Despite extensive pneumocephalus, no neurological sign or spinal instability was evident. In this case 4000 cGy of radiation in 200-cGy fractions was administered to the diseased area while the patient was kept in a Miami-J collar. At the 2-year follow-up examination, arrest of the disease process and new bone formation was evident on radiographic studies.

Cervical Vertebrae↗
PubMed1995

Functional roles of in vivo footprinted DNA motifs within an alpha-globin enhancer. Erythroid lineage and developmental stage specificities.

Transcriptional regulation of the human alpha-like globin genes, embryonic zeta 2 and adult alpha, during erythroid development is mediated by a distal enhancer, HS-40. Previous protein-DNA binding studies have shown that HS-40 consists of multiple nuclear factor binding motifs that are occupied in vivo in an erythroid lineage- and developmental stage-specific manner. We have systematically analyzed the functional roles of these factor binding motifs of HS-40 by site-directed mutagenesis and transient expression assay in erythroid cell cultures. Three of these HS-40 enhancer motifs, 5'NF-E2/AP1, GT II, and GATA-1(c), positively regulate the zeta 2-globin promoter activity in embryonic/fetal erythroid K562 cells and the adult alpha-globin promoter activity in adult erythroid MEL cells. On the other hand, the 3'NF-E2/AP1 motif is able to exert both positive and negative regulatory effects on the zeta 2-globin promoter activity in K562 cells, and this dual function appears to be modulated through differential binding of the ubiquitous AP1 factors and the erythroid-enriched NF-E2 factor. Mutation in the GATA-1(d) motif, which exhibits an adult erythroid-specific genomic footprint, decreases the HS-40 enhancer function in dimethyl sulfoxide-induced MEL cells but not in K562 cells. These studies have defined the regulatory roles of the different HS-40 motifs. The remarkable correlation between genomic footprinting data and the mutagenesis results also suggests that the erythroid lineage- and developmental stage-specific regulation of human alpha-like globin promoters is indeed modulated by stable binding of specific nuclear factors in vivo.

Adult↗
PubMed1995

Positron emission tomography in drug evaluation: influence of three different catechol-O-methyltransferase inhibitors on metabolism of [NCA] 6-[18F]fluoro-L-dopa in rhesus monkey.

We compared the influence of three different catechol-O-methyltransferase (COMT) inhibitors (CGP 28014, OR-611 and Ro 40-7592) on the metabolism of no-carrier-added (NCA) 6-[18F]fluoro-L-dopa (6-FDOPA) in one Rhesus monkey. All three COMT inhibitors improved 6-FDOPA availability in plasma, increased the specific uptake in the brain and thus improved 6-FDOPA uptake measurements using positron emission tomography (PET). Best results were obtained with Ro 40-7592.

Amidines↗
PubMed1994

Evaluation of osteoporosis in patients with fracture neck of femur using conventional radiography.

Osteoporosis was assessed at the hip (Singh's index) and calcaneus (calcaneal index) using conventional radiography in 80 patients (31 men, 49 women) with fracture neck of femur. Forty four patients had intracapsular fracture neck of femur (ICFN), and 36 extracapsular fracture neck of femur (ECFN). Fractures occurred more with increasing age in both groups, with female preponderance in the older age group. Osteoporosis was more severe as age advanced. Singh's index decreased from 5.2 to 3 (ICFN), and from 4.1 to 2.65 (ECFN) with age. Calcaneal index decreased from 4.4 to 2.9 (ICFN) and from 4.1 to 2.6 (ECFN) with age. In summary degree of osteoporosis, assessed at the hip and calcaneus, increased with increasing age. Other recent studies have shown that calcaneal bone density is a valid method to predict future risk of hip fracture.

Adult↗
PubMed1993

Quality assurance and quality control methods for animal and human applications of no-carrier-added 6-[18F]fluorodopa for PET investigations of dopaminergic systems.

No-Carrier-Added (NCA) 6-[18F]fluoro-L-dopa (6-FDOPA) is being produced routinely for PET investigations of dopaminergic systems at our Institute. We describe here in detail the quality assurance methods involved in its multi-step developmental stage as a radiopharmaceutical. A method to remove toxic copper ions to prepare an injectable solution is described. The stability and shelf-life of NCA 6-FDOPA was also examined and results are discussed. Quality control involved three major aspects: (a) chemical purity, (b) radiochemical purity and (c) enantiomeric excess. A method for quick quality control of individual batch preparations is described.

Animals↗
PubMed1989

Progressive unilateral hydrocephalus in adults.

Unilateral dilatation of the lateral ventricle in adults is rare. We report 2 cases of unilateral hydrocephalus with obstruction at the foramen of Monro. Both patients presented with symptoms of raised intracranial pressure.

Adult↗
PubMed1988

Evaluation of brainstem auditory evoked responses in congenital hydrocephalus.

Brainstem auditory evoked responses (BAER) were studied in 20 children with clinically diagnosed and CT-confirmed congenital hydrocephalus before and after shunt surgery. Ninety-five percent of the children showed abnormal responses preoperatively. Prolonged wave V latency was the most common abnormality, followed by increased interwave latencies. Total absence of evoked responses was more common in children with communicating hydrocephalus. Following shunt surgery 50% of cases returned to normal and 20% showed a significant improvement. Abnormalities persisted in 10% of cases. BAER abnormalities referrable to caudal brainstem dysfunction recovered first, following CSF diversion. Study of BAER is useful for identifying physiological brainstem abnormalities in hydrocephalic children and promises to be a sensitive non-invasive diagnostic tool for the detection of "non-infective complications" of shunt surgery, if performed serially during follow up.

Brain Stem↗
PubMed1987

Benign subarachnoid haemorrhage (subarachnoid haemorrhage of unknown aetiology).

Forty three patients of subarachnoid haemorrhage of unknown aetiology have been studied for their clinical presentation, rebleed rate, morbidity and mortality. The results have been compared with other similar studies. The present study and those of others indicate a very good prognosis in acute stage. The rebleed rate ranged between 0 and 7% over a period of two to three years. The mortality rate ranged between 0 and 5% during the same period of follow-up. Majority of the patients returned to their full working capacity. The benign nature of this subgroup as compared to the poor outcome of subarachnoid haemorrhage as a whole prompted us to call it "Benign subarachnoid haemorrhage".

Female↗
PubMed1984

Intraspinal arachnoid cysts.

Arachnoid cysts are rare lesions responsible for spinal cord compression. Five cases of congenital intraspinal arachnoid cysts are reported. Three cases of thoracic and two cases of thoracolumbar region were encountered. The clinical presentation was one of progressive spastic paraparesis. The characteristic radiological features are described. Surgery was successful in all cases.

Adolescent↗
PubMed1983

A variable pulse-burst electromagnetic generator for electrical stimulation of biological systems.

A variable frequency-burst type, electromagnetic pulse generator has been developed to optimize the effect of electrical stimulation on bone growth. Using a pair of coils, with 100 turns and 18-gauge wire, the instrument can generate a maximum magnetic field of 300 Gauss. Its pulse repetition frequency can be varied from 10 Hz to 2 KHz and the duty cycle, consisting of several short carrier frequency pulses, can be varied up to 95%. This design also permits the period of the carrier pulse to be changed.

Animals↗