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Biomedical subjects

Rajesh Patel

Publications and source records attributed to Rajesh Patel.

14 recordsLinked to original sources
PubMed2006

Sodium valproate vs phenytoin in status epilepticus: a pilot study.

Sixty-eight patients with convulsive status epilepticus (SE) were randomly assigned to two groups to study the efficacy of sodium valproate (VPA) and phenytoin (PHT). Seizures were aborted in 66% in the VPA group and 42% in the PHT group. As a second choice in refractory patients, VPA was effective in 79% and PHT was effective in 25%. The side effects in the two groups did not differ. Sodium valproate may be preferred in convulsive SE because of its higher efficacy.

Adolescent↗
PubMed2006

Appropriate use of pagers in a New Zealand tertiary hospital.

AIMS: To identify the appropriateness of calls to on-call house officers in a major tertiary teaching hospital. METHODS: A prospective observational study was conducted at Auckland City Hospital over the months of June, July, and August 2004. Fourteen house officers from a range of medical and surgical services categorised calls received while on-call after-hours into one of three groups: 'appropriate and urgent'; 'appropriate but not urgent'; and 'inappropriate'. RESULTS: 844 calls were recorded and categorised, with approximately even distribution between medical services (431 calls) and surgical services (413 calls); 30% of calls were deemed clinically appropriate and required a response within 1 hour; 53% of calls were deemed clinically appropriate but did not require a response within an hour; while 17% of calls were deemed inappropriate. CONCLUSIONS: The most important function an on-call house officer performs is responding to urgent medical situations. Frequent interruptions mean that house officers may become less efficient and more prone to making mistakes. The majority of calls received by on-call house officers did not need immediate responses and would have been better communicated via a less intrusive system such as text-messaging or the keeping of a non-urgent jobs list. If house officers were paged more appropriately then they would be interrupted less frequently and would be able to provide safer, more efficient, and timelier patient care.

Health Knowledge, Attitudes, Practice↗
PubMed2006

Experimental evidence of zero forward scattering by magnetic spheres.

Magnetically induced diffraction patterns by micron sized magnetic spheres dispersed in a ferrofluid disappear at a certain critical magnetic field. This critical field is found to depend on the concentration of the ferrofluid and on the volume of the magnetic spheres. We attribute this effect to the zero forward scattering by magnetic spheres as predicted by Kerker, Wang, and Giles [J. Opt. Soc. Am. 73, 765 (1983)]. We suggest that such a dispersion can be used to study the optical analogues of localization of electrons in condensed matter, the Hall effect, and the anisotropic diffusion, etc. The combination of the micron sized magnetic spheres and the ferrofluid will also be useful to design magnetically tunable photonic devices.

Journal Article↗
PubMed2006

A comparative study of sperm morphology, cytology and activation in Caenorhabditis elegans, Caenorhabditis remanei and Caenorhabditis briggsae.

Studies of sterile mutants in Caenorhabditis elegans have uncovered new insights into fundamental aspects of gamete cell biology, development, and function at fertilization. The genome sequences of C. elegans, Caenorhabditis briggsae and Caenorhabditis remanei allow for informative comparative studies among these three species. Towards that end, we have examined wild-type sperm morphology and activation (spermiogenesis) in each. Light and electron microscopy studies reveal that general sperm morphology, organization, and ultrastructure are similar in all three species, and activation techniques developed for C. elegans were found to work well in both C. briggsae and C. remanei. Despite important differences in the reproductive mode between C. remanei and the other two species, most genes required for spermiogenesis are conserved in all three. Finally, we have also examined the subcellular distribution of sperm epitopes in C. briggsae and C. remanei that cross-react with anti-sera directed against C. elegans sperm proteins. The baseline data in this study will prove useful for the future analysis and interpretation of sperm gene function across nematode species.

Amino Acid Sequence↗
PubMed2006

Impact of formulation excipients on human intestinal transit.

The accelerating effect of polyethylene glycol 400 on small intestinal transit has been previously reported. The aim of this study was to investigate the influence of other solubility-enhancing excipient, propylene glycol, D-alpha-tocopheryl-polyethylene glycol-1,000 succinate (VitE-TPGS) and Capmul MCM, on human intestinal transit. A 5-g dose of each excipient was administered to seven healthy male subjects. Propylene glycol and VitE-TPGS were administered dissolved in 150 mL water. Capmul MCM was administered in the form of four 000 hard gelatin capsules to mask its taste and then given with 150 mL water. On a separate occasion, 150 mL water was administered as the control. Each formulation was radiolabelled with technetium-99 m to follow its transit using a gamma camera. The mean small intestinal transit times were 234, 207, 241 and 209 min for the control, propylene glycol, VitE-TPGS and Capmul MCM treatments, respectively. Although there were differences in the small intestinal transit times for the excipients investigated compared with the control, none of the results were statistically significant. Unlike polyethylene glycol 400 at the same dose of 5 g, the excipients tested (propylene glycol, VitE-TPGS and Capmul MCM) had little or no impact on small intestinal transit.

Adult↗
PubMed2006

Molecular classification of human cancers using a 92-gene real-time quantitative polymerase chain reaction assay.

CONTEXT: Correct diagnosis of the tissue origin of a metastatic cancer is the first step in disease management, but it is frequently difficult using standard pathologic methods. Microarray-based gene expression profiling has shown great promise as a new tool to address this challenge. OBJECTIVE: Adoption of microarray technologies in the clinic remains limited. We aimed to bridge this technological gap by developing a real-time quantitative polymerase chain reaction (RT-PCR) assay. DESIGN: We constructed a microarray database of 466 frozen and 112 formalin-fixed, paraffin-embedded (FFPE) samples of both primary and metastatic tumors, measuring expression of 22,000 genes. From the microarray database, we used a genetic algorithm to search for gene combinations optimal for multitumor classification. A 92-gene RT-PCR assay was then designed and used to generate a database for 481 frozen and 119 FFPE tumor samples. RESULTS: The microarray-based K-nearest neighbor classifier demonstrated 84% accuracy in classifying 39 tumor types via cross-validation and 82% accuracy in predicting 112 independent FFPE samples. We successfully translated the microarray database to the RT-PCR platform, which allowed an overall success rate of 87% in classifying 32 different tumor classes in the validation set of 119 FFPE tumor samples. CONCLUSIONS: The RT-PCR-based expression assay involving 92 genes represents a powerful tool for accurately and objectively identifying the site of origin for metastatic tumors, especially in the cases of cancer of unknown primary. The assay uses RT-PCR and routine FFPE samples, making it suitable for rapid clinical adoption.

Algorithms↗
PubMed2005

West Nile Virus: a case report with flaccid paralysis and cervical spinal cord: MR imaging findings.

We present a case of serologically proved West Nile virus (WNV) flaccid paralysis of the right upper extremity. Radiologic correlation revealed striking T2 hyperintensities in the anterior horns of the cervical spinal cord, similar to those seen in cases of poliomyelitis. Recognition of the MR imaging findings in cases of WNV flaccid paralysis can provide early evidence of infection.

Anterior Horn Cells↗
PubMed2004

Magneto-optical effects in temperature-sensitive ferrofluids.

A temperature-dependent magneto-optical study of three different temperature-sensitive fluids was carried out. The changes in transmitted intensity as a function of applied magnetic field and temperature are recorded. The study provides an alternative technique for determining the Curie temperature of such fluids, and it is also feasible for the monitoring of temperature changes of such fluids optically within a limited time span.

Journal Article↗
PubMed2004

An evaluation of the United Kingdom National Osteoporosis Society position statement on the use of peripheral dual-energy X-ray absorptiometry.

A recent position statement issued by the UK National Osteoporosis Society recommends a triage approach to the use of peripheral dual-energy X-ray absorptiometry (pDXA) devices. Patients with a forearm T-score greater than -1 or less than -2.5 are regarded as normal or osteoporotic, respectively, while those with a T-score between -1 and -2.5 are sent for further assessment with spine and hip DXA. We have evaluated the NOS pDXA algorithm by comparing it with the alternative strategies of relying on forearm BMD alone, or performing spine and hip DXA in every patient. The evaluation was carried out using a mathematical model, and the predictions were compared with in vivo data obtained in patients referred for investigation by their general practitioner. In the model the population distribution of spine, hip, and forearm BMD was described by a trivariant Gaussian function. Relative risks of fracture were taken from a meta-analysis. The three strategies were compared using receiver operating characteristic (ROC) curves in which the percentage of future fracture cases identified was plotted against the percentage of the whole population found to have osteoporosis. ROC curves plotted for the discrimination of hip, vertebral, and Colles fracture risk and the risk of a fracture at any skeletal site were similar for all three strategies, with the curves for the NOS pDXA algorithm nearly identical to those for spine and hip DXA. For the case of hip fracture, vertebral fracture, or a fracture at any site, forearm BMD was slightly inferior to the NOS algorithm, but the reverse was true for Colles fracture. The small difference between the ROC curves suggests that forearm BMD used alone can reproduce clinical decision-making with the NOS pDXA algorithm provided that a T-score threshold of T=-2.1 is used for the diagnosis of osteoporosis, instead of the conventional figure of T=-2.5. Results from the in vivo study were in good agreement with the predictions of the model, although some differences were observed that were explained by inaccuracies in the forearm reference data. We conclude that use of forearm BMD alone with a modified T-score threshold of -2.1 would save the need for spine and hip DXA scans and identify only slightly fewer fracture cases for treatment.

Absorptiometry, Photon↗
PubMed2004

cAMP-dependent protein kinase of Manduca sexta phosphorylates but does not activate the fat body triglyceride lipase.

cAMP-dependent-protein kinase (PKA) is a central player of the adipokinetic signal that controls the mobilization of stored lipids in the fat body. Previous studies showed that adipokinetic hormone (AKH) rapidly activates PKA from the fat body of Manduca sexta (Arrese et al. (J. Lipid. Res. 40(3): 556)). As a part of our investigation on lipolysis in insects, here we report the purification and characterization of the catalytic subunit of PKA from the fat body of M. sexta and its role in the direct activation of the TG lipase in vitro. PKA was purified to apparent homogeneity and the identity of the protein was confirmed by MALDI-TOF and Western blot analysis. The enzyme showed a high affinity for Mg-ATP (Km = 39 microM) and Kemptide (Km = 31 microM) and was strongly inhibited by the PKA specific inhibitors PKI 5-24 and H89. Manduca sexta PKA only recognized serine residues as phosphate acceptor; theronine or tyrosine containing peptides were not phosphorylated. Purified fat body TG-lipase proved to be a good substrate of the purified kinase. However, phosphorylation of the lipase did not enhance the lipolytic activity of the enzyme in vitro. These results suggest that, besides lipase phosphorylation, the mechanism of AKH-induced activation of the lipolysis requires the involvement of other proteins and/or signals.

Amino Acid Sequence↗
PubMed2003

Potent small molecule inhibitors of spleen tyrosine kinase (Syk).

A series of oxindoles demonstrating inhibition of the phosphorylation of biotinylated substrates of Syk and IgE/Fc epsilon RI triggered basophil cell degranulation has been identified. A study of the SAR around sulfonamide 31 (IC(50)=5 nM, EC(50)=1400 nM) is discussed. The modest cellular activity representative of the sulfonamide series was overcome when the Polar Surface Area was lowered to <110 A(2), leading to the identification of amide 32 (IC(50)=145 nM, EC(50)=100 nM).

Animals↗
PubMed2003

Does the combination of two BMD measurements improve fracture discrimination?

UNLABELLED: Combining information from different types of BMD measurement should improve the evaluation of patients' risk of fracture. This study used a bivariate gaussian model to examine the effect of combining two different BMD measurements. The results show that, in practice, there is little benefit unless the measurements are completely unrelated. INTRODUCTION: Intuitively, the combination of information from two or more different types of bone densitometry investigation should improve our ability to identify patients at high risk of fracture. However, the best way to combine measurements and the resulting gain in fracture discrimination are not known. MATERIALS AND METHODS: In this study, we used a bivariate gaussian model to investigate the effect of combining two different types of bone densitometry measurements. The measurements had individual relative risk values RR1 and RR2 and a correlation coefficient r between their Z-scores. Different approaches to the combination of the two measurements were compared by calculating the area under the curve (AUC) for the receiver operating characteristic (ROC) curve, which was obtained by plotting the percentage of fracture patients against the percentage of the whole population with a Z-score below some chosen threshold. ROC curves were calculated for three cases: (1) one type of measurement only; (2) two different types of measurements combined using their mean Z-score weighted according to the theoretical optimum weighting factors predicted by the bivariate gaussian model; and (3) two different types of measurements combined using the conventional World Health Organization (WHO) approach, where one or other measurement is below a set threshold. The theoretical model was tested using measurements of speed of sound (SOS) in the radius, phalanx, and metatarsal in patients with vertebral and Colles' fractures. RESULTS: Results were calculated for RR values of 1.5, 2.0, and 2.5 and r = 0, 0.5, and 0.7. Although a significant improvement in fracture discrimination was obtained when r = 0 and RR1 = RR2, the improvements obtained when r > or = 0.5 or RR1 double dagger RR2 were relatively modest. Slightly better fracture discrimination was obtained using the weighted mean Z-score approach compared with the WHO approach, although the differences were small. The results of the in vivo study in Colles' and vertebral fracture patients showed close agreement with the predictions of the bivariate gaussian model. CONCLUSION: In practice, from a theoretical point of view, there is unlikely to be any benefit from combining information from different types of bone densitometry measurements unless they are completely unrelated.

Bone Density↗
PubMed2002

Development of grain threshers based on ergonomic design criteria.

Threshers are used extensively on Indian farms for threshing grains, but are involved in a significant proportion of limb crush injuries. International safety standards are somewhat difficult to enforce because manufacture of machines is done at widely dispersed local workshops. Locally made machines are used for crop production and post-harvesting operations, with a great deal of manual work. This technical note reports the results of a study to develop a cost effective, improved design for safe operation of threshers based on ergonomic principles.

Accidents, Occupational↗