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Biomedical subjects

V Parmar

Publications and source records attributed to V Parmar.

At least 19 recordsLinked to original sources

Comparison of accuracy of lag screw placement in cephalocondylic nails and sliding hip screw plate fixation for extracapsular fractures of the neck of femur.

This study compared the accuracy of lag screw placement between extracapsular femoral fractures fixed with sliding hip screw plate systems and those fixed with cephalocondylic nails. It involved 75 retrospective radiographs of fractures fixed with either a cephalocondylic nail (32) or a sliding hip screw plate system (43). Postoperative anteroposterior and lateral radiographs of the hip were scanned using a digital X-ray scanner and measured using computer software. Measurements were conducted by two independent observers, and the radiographs were calibrated to correct for magnification. Accuracy of lag screw placement was determined by "tip apex distance," described by Baumgaertner et al., and by the ratio method described by Parker. The mean tip apex distance was 24.0 mm in sliding hip screw plate systems and 21.1 mm in cephalocondylic nails. This was found to be statistically significant. Lag screw placement through cephalocondylic nails is more accurate and therefore has less chance of cut-out compared with sliding hip screw plate systems. There was no statistically significant difference using Parker's ratio method because this method quantifies the direction of the screw rather than the depth of penetration.

Bone Nails↗

Surgical reconstruction for absence of sternum and pericardium in a newborn.

We report the surgical management of a 3 day old baby with absent sternum and pericardium with impending rupture of the skin cover. The repair described is innovative and may be used in place of primary repair by bringing the ribs together. Review of embryology and various modalities of closure are provided.

Abnormalities, Multiple↗

Aberrant subclavian artery causing difficulty in transhiatal esophageal dissection.

The right subclavian artery normally arises from the brachiocephalic artery. Anomalies in development may lead to peculiar problems during surgery. We report a patient with esophageal carcinoma who had an aberrant right subclavian artery, posing specific difficulties during a transhiatal esophagectomy, requiring conversion of the procedure into a transthoracic approach. The embryologic basis of this anomaly and the clinical significance are discussed.

Carcinoma, Squamous Cell↗

Perinatal tuberculosis.

Perinatal tuberculosis is insufficiently understood. Its early diagnosis is essential but often difficult as the initial manifestations may be delayed. Improved screening of women at risk and sensitivity of the medical community are necessary. A coherent system of cooperation between the hospital and community services and between pediatricians and adult physicians is indispensable to find the index adult case to break the chain of contagion as well as to offer prophylactic therapy to the children at risk. We hereby report a baby with perinatal tuberculosis who was not offered any prophylactic therapy inspite of the mother being diagnosed to have pulmonary tuberculosis.

Adult↗

Pseudohypoparathyroidism in a mother and son: phenotypic variability and associated disorder.

A 2-month-old infant with clinical features of hypothyroidism presented with hypocalcemic seizures. The maternal phenotypic features aroused the suspicion of pseudohypoparathyroidism which was confirmed in both by biochemical and endocrinological investigations. Though the child had clinical and radiological features to suggest hypothyroidism he had normal free thyroxine and only slightly elevated thyroid stimulating hormone levels. Special note is made of the intra and interpatient variability of this rare inherited disorder.

Adult↗

Neonatal parotitis.

Neonatal parotitis is a rare condition. Infection of the parotid glad is more common than that of the submandibular glad. Dehydration is the most important predisposing factor for this. Most common organism responsible for this condition is Staphylococcus aureus. Untreated condition can lead to various complications.

Humans↗

Hyperimmunoglobulin E syndrome.

Hyperimmunoglobulin E (HIE) syndrome is a primary immunodeficiency disorder characterized by recurrent bacterial infections in presence of very high serum Ig E levels. We are reporting a nine-year-old child with HIE syndrome and reviewing literature on this disease.

Bone Diseases, Metabolic↗

Mode of action of (R)-9-[4-hydroxy-2-(hydroxymethyl)butyl]guanine against herpesviruses.

The activity, metabolism, and mode of action of (R)-9-[4-hydroxy-2-(hydroxymethyl)butyl]guanine (H2G) against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) and varicella-zoster virus (VZV) were studied. Compared to acyclovir (ACV), H2G has superior activity against VZV (50% inhibitory concentration of 2.3 microM) and Epstein-Barr virus (50% inhibitory concentration of 0.9 microM), comparable activity against HSV-1, and weaker activity against HSV-2. The antiviral effect on HSV-1 showed persistence after removal of compound. H2G was metabolized to its mono-, di- and triphosphate derivatives in virus-infected cells, with H2G-triphosphate being the predominant product. Only small amounts of H2G-triphosphate were detected in uninfected cells (1 to 10 pmol/10(6) cells), whereas the level in HSV-1-infected cells reached 1,900 pmol/10(6) cells. H2G was a substrate for all three viral thymidine kinases and could also be phosphorylated by mitochondrial deoxyguanosine kinase. The intracellular half-life of H2G-triphosphate varied in uninfected (2.5 h) and infected (HSV-1, 14 h; VZV, 3.7 h) cells but was always longer than the half-life of ACV-triphosphate (1 to 2 h). H2G-triphosphate inhibited HSV-1, HSV-2, and VZV DNA polymerases competitively with dGTP (Ki of 2.8, 2.2, and 0.3 microM, respectively) but could not replace dGTP as a substrate in a polymerase assay. H2G was not an obligate chain terminator but would only support limited DNA chain extension. Only very small amounts of radioactivity, which were too low to be identified by high-performance liquid chromatography analysis of the digested DNA, could be detected in purified DNA from uninfected cells incubated with [3H]H2G. Thus, H2G acts as an anti-herpesvirus agent, particularly potent against VZV, by formation of high concentrations of relatively stable H2G-triphosphate, which is a potent inhibitor of the viral DNA polymerases.

Antiviral Agents↗

Rapid purification and characterisation of HIV-1 reverse transcriptase and RNaseH engineered to incorporate a C-terminal tripeptide alpha-tubulin epitope.

The C-termini of p66 and p51 forms of HIV-1 reverse transcriptase have been engineered to contain a Glu-Glu-Phe sequence recognized by a monoclonal antibody to alpha-tubulin, YL1/2. Mutated RTs were purified in a single step using peptide elution from columns of immobilized YL1/2. The known sequence requirements of the YL1/2 epitope are consistent with protein eluting from the column with an intact C-terminus. Kinetic parameters of these mutated RTs are essentially unchanged from wild-type enzyme. The p15 RNaseH domain has been purified using this method and shown to have low enzyme activity compared to the parental p66 subunit.

Amino Acid Sequence↗

Mutational analysis of two conserved sequence motifs in HIV-1 reverse transcriptase.

Two conserved sequence motifs, occurring in HIV-1 reverse transcriptase at residues 110-116 and 183-190, have been studied using site-directed mutagenesis of the cloned gene. In particular, aspartates at positions 185 and 186 have each been mutated to either asparagine or glutamate. The resulting mutant proteins were catalytically inactive but still able to bind the template-primer complex, poly rA-oligo dT. Other mutations in these regions resulted in reduced reverse trascriptase activity but the mutation of tyrosine-183 to serine caused a significant increase in the Km for dTTP and the Ki for inhibition by 3'-azidothymidine-triphosphate, 2',3'-dideoxythymidine-triphosphate and phosphonoformic acid.

Amino Acid Sequence↗

Gastric proteases in the human infant.

The electrophoretic mobilities of proteases present in gastric juice taken within 10 h of birth from 5 healthy, premature infants were compared with calf chymosin, pig pepsin A and human adult gastric juice. The juice from 2 infants contained predominantly a chymosin-like enzyme, another had almost exclusively pepsins similar to those of the adult juice, while the other two contained a mixture of both. The pepsins consisted of two elements, probably pepsin A (EC 3.4.23.1), and pepsin C (EC 3.4.23.3). Single radial immunodiffusion gave a definite reaction to calf anti-chymosin serum in five samples taken from a further 17 infants. These results indicate that some human infants secrete chymosin. The reaction in the immunodiffusion assay indicated a much lower enzyme activity than that implied from electrophoretic separations. It is suggested that species differences resulted in poor cross-reactivity of the antiserum.

Chymosin↗

Stool water in preterm neonates.

Data are presented on faecal water losses in 93 preterm infants being fed breast milk (72 infant days) or formula (280 days). Losses per kg increased to 4 weeks, when they amounted to 11% of water requirement in infants fed breast milk and 8% in infants fed formula.

Body Water↗