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Biomedical subjects

P S Rao

Publications and source records attributed to P S Rao.

At least 19 recordsLinked to original sources
PubMed2005

Total percutaneous correction of a tetralogy of Fallot variant with dominant pulmonary valve stenosis.

OBJECTIVE: To study the feasibility, efficacy, and safety of total percutaneous correction of a tetralogy of Fallot variant with dominant pulmonary valve stenosis. DESIGN: Percutaneous correction of a variant of tetralogy of Fallot with dominant pulmonary valve stenosis, on the basis that there are transcatheter methods for the correction of malalignment-type ventricular septal defect (VSD) (transcatheter patch) and valvar pulmonary stenosis (balloon valvoplasty). PATIENTS: Two patients with tetralogy of Fallot, 4 and 7 years old, were admitted for percutaneous correction. Their aortic saturations were 72% and 88%. Both had severe right ventricular outflow obstruction with dominant valvar pulmonary stenosis with total gradients of 120 and 70 mm Hg. Large malalignment subaortic VSDs, 14 and 16 mm in diameter, were present. The first patient had a previous percutaneous correction of a small atrial septal defect and an aortopulmonary collateral. INTERVENTIONS: Balloon valvoplasty was first performed, followed by balloon test occlusion of the VSD and double balloon patch occlusion. Forty eight hours after implantation the supporting balloons were extracted, releasing the patches. RESULTS: Both patients became acyanotic with oxygen saturations of 96%. There was mild residual infundibular stenosis with 40 and 30 mm Hg gradients. Both VSDs were effectively occluded with only trivial residual shunts. One patient developed mild haemolysis, which resolved spontaneously in a few days. Both patients were doing well at six and 12 months' follow up visits. CONCLUSIONS: Total percutaneous correction of the tetralogy of Fallot variants with dominant pulmonary valve stenosis is feasible and successful. Larger clinical trials are required to further assess effectiveness and safety.

Catheterization↗
PubMed2005

Inhibition of bacterial adhesion by subinhibitory concentrations of antibiotics.

BACKGROUND: Urinary Tract Infections (UTIs) due to Escherichia coli is one of the most common diseases encountered in clinical practice. Most common recognised pathogenic factor in E.coli is adhesion. There is accumulating evidence that through subinhibitory concentrations (sub-MICs) of many antibiotics do not kill bacteria, they are able to interfere with some important aspects of bacterial cell function. MATERIALS AND METHODS: A study was conducted to investigate the effect of sub MICs (1/2-1/8 MIC) of ciprofloxacin, ceftazidime, gentamicin, ampicillin and co-trimoxazole on E. coli adhesiveness to human vaginal epithelial cells using three strains ATCC 25922, MTCC 729 and U 105. RESULTS: The 1/2 MIC of all the antibiotics tested produced the greatest inhibition of bacterial adhesion. Morphological changes were observed with ciprofloxacin, ceftazidime and ampicillin at 1/2 MIC and to a lesser extent at 1/4 and 1/8 MIC. Co-trimoxazole caused the greatest suppression of adhesion at 1/2 MIC of E. coli strain MTCC 729 when compared with the controls, followed by ceftazidime. CONCLUSION: These results suggest that co-trimoxazole is the most effective antibiotic in the treatment of urinary tract infections caused by uropathogenic E. coli.

Anti-Bacterial Agents↗
PubMed2005

Survey of Staphylococcus isolates among hospital personnel, environment and their antibiogram with special emphasis on methicillin resistance.

The objective of this study was to find the prevalence of Staphylococcus spp. carriage among hospital personnel and hospital environment and their antibiogram with special emphasis on methicillin resistance. A total of 205 samples from hospital personnel and environment were collected from casualty, oncology and multidisciplinary cardiac unit ward of Kasturba Medical College Hospital, Manipal. Samples were collected using sterile cotton wool swabs and inoculated into brain heart infusion broth. Subcultures were done onto blood agar and MacConkey's agar. Isolates were identified by standard methods up to species level. Antimicrobial susceptibility test was performed according to standardized disc diffusion Kirby-Bauer method. Each of the isolates was screened for methicillin resistance using oxacillin disc on Mueller Hinton agar plate followed by MIC for methicillin and cefoxitin susceptibility test by disc diffusion method. Sixty five out of 205 strains (31.7%) were Staphylococcus spp. and all of them were coagulase negative. Most of the strains belonged to S.epidermidis 49.23% (32/65) followed by S. saprophyticus 26.15% (17/65). Maximum isolates of S.epidermidis were from anterior nares 28.12% (9/32 strains of S.epidermidis). Highest number of methicillin resistant coagulase negative strains (3/9, 33.33%) were isolated from stethoscope of multidisciplinary cardiac unit ward followed by carriers in the anterior nares (2/9, 22.22%). Methicillin resistant coagulase negative staphylococci are prevalent in anterior nares of hospital personnel and in the hospital environment thereby providing a definite source for hospital acquired infection. All isolates were sensitive to vancomycin, ciprofloxacin and amikacin.

Anti-Bacterial Agents↗
PubMed2004

Single crystal EPR studies of paramagnetic ions doped zinc potassium phosphate hexahydrate; Part III: Mn(II)-a case of rhombic distortion.

Single crystal electron paramagnetic resonance (EPR) studies of Mn(II) doped zinc potassium phosphate hexahydrate have been carried out at room temperature. Single crystal rotations along the three orthogonal axes indicate orthorhombic symmetry with spin-Hamiltonian parameters as: g(xx) = 1.9997; g(yy) = 1.9538; g(zz) = 1.9524, D(xx) = 15.49 mT; D(yy) = 0.22 mT; D(zz) = -15.71 mT, A(xx) = 11.70 mT; A(yy) = 10.53 mT; A(zz) = 10.42 mT and a = 0.8 x 10(-4) cm(-1). A large E term indicates considerable distortion from axial symmetry. The impurity is found to enter the lattice substitutionally. The distortion axis for the impurity has been identified along one of the Zn-O bond directions in the crystal.

Electron Spin Resonance Spectroscopy↗
PubMed2004

Short-term physical training alters cardiovascular autonomic response amplitude and latencies.

This study reports the results of 15 days of exercise training in 25 adult males on cardiovascular autonomic response amplitude and latencies. A standard battery of autonomic function tests including both activity (tone) and reactivity was used. Parasympathetic activity as evaluated from Heart rate variability (HRV) showed no statistically significant change in both time and frequency domain measures, similarly Sympathetic activity as measured by QT/QS2 ratio showed no statistically significant change, but there was a trend of a decrease in sympathetic activity and an increase in parasympathetic activity. There were no changes in the parameters measuring parasympathetic reactivity. Sympathetic reactivity as evaluated by diastolic blood pressure responses to hand grip test (HGT) and cold pressor test (CPT) showed significant decreases. Time domain assessment of autonomic responses was done by measuring tachycardia and bradycardia latencies during Valsalva maneuver (VM) and lying to standing test (LST). Physical training resulted in a decrease in tachycardia latency during LST and a decrease in bradycardia latency during VM. We conclude from the present study that 15 days of physical training is not enough to alter autonomic activity and PNS reactivity but can result in changes in SNS reactivity and latency parameters. We hypothesize that a decrease in bradycardia latency during VM signifies a faster recovery of heart rate during VM and a decrease in tachycardia latency during LST denotes a delayed activation of the system both of which are favorable cardiovascular responses.

Adult↗
PubMed2003

Optical and EPR studies of iron bearing phosphate minerals: satterlyite and gormanite from Yukon Territory, Canada.

The iron phosphate minerals satterlyite and gormanite have been investigated by EPR and optical absorption studies. The optical results indicate the presence of ferrous and ferric ions in both minerals. In gormanite the site symmetry of Fe(III) is near octahedral whereas in satterlyite it is tetragonally distorted. On the other hand, the Fe(II) ions are in tetragonally distorted octahedral site in both minerals. In satterlyite the EPR results indicate the presence of the ferric ion in a tetragonally distorted state together with a small percentage of Mn(II). Crystal field (Dq) and interelectronic parameters (B and C) are evaluated.

Iron↗
PubMed2003

Optical absorption and EPR spectra of fuchsite.

Chromium containing mica is called fuchsite. Fuchsite originating from the Nellore district of India containing 3.37 wt.% of chromium is used in the present study. Optical absorption and EPR studies were carried out at room temperature (RT). The optical absorption spectrum gives energies at 14925, 15070, 15715, 16400, 17730 and 21740 cm(-1), which are attributed to spin-allowed transitions for Cr(3+) in an octahedral symmetry. EPR spectra show a strong resonance with g=1.98 along with two sets of weak resonances which are attributed to two sets of chromium in the sample. The zero field splitting parameter (D) is almost zero. These spectra are due to Cr(3+) in the mineral. The NIR spectrum is due to hydroxyl ions in the sample.

Aluminum Silicates↗
PubMed2003

99mTc-peptide-peptide nucleic acid probes for imaging oncogene mRNAs in tumours.

Imaging oncogene mRNA in tumours would provide a powerful tool for the early detection of occult malignant lesions. The goal was to prepare a chimera consisting of a dodecamer antisense peptide nucleic acid (PNA) specific for c-MYC oncogene overexpressed in human breast cancer cells and a chelating moiety that facilitates quantitative radiolabelling with 99mTc and evaluate it for hybridization and tissue distribution in laboratory animals. The pentapeptide chelator-PNA dodecamer specific for c-MYC mRNA was extended from a solid support by 9-fluorenylmethyloxycarbonyl (Fmoc) coupling. Similarly, a chelator-PNA chimera with four central mismatches was also prepared which served as a control. The chimeras were purified, characterized and evaluated for hybridization to c-MYC mRNA by fluorescent, real-time polymerase chain reaction (RT-PCR). The chimeras were labelled with 99mTc and their tissue distribution was examined in athymic nude mice bearing experimental human breast tumours. 99mTc radiolabelling was quantitative and presented a single peak in reversed phase liquid chromatography. Fluorescent real-time polymerase chain reactions using primer and fluorescent probe sets previously calculated for c-MYC mRNA demonstrated inhibition of reverse transcription by the c-MYC specific chimera as compared to that of the control. Tissue distribution studies of antisense and mismatch chimeras at 4 h and 24 h after administration displayed modest accumulation in the liver, and appreciable levels in tumours. These observations suggest that 99mTc-peptide-PNA probes might be useful for imaging gene expression in tumours, and the approach is worthy of further investigation.

Animals↗
PubMed2001

Gaseous transport of volatile organic chemicals in unsaturated porous media: effect of water-partitioning and air-water interfacial adsorption.

Laboratory experiments were conducted employing gas chromatographic techniques to evaluate the gaseous transport of volatile organic chemicals (VOCs) in water-unsaturated soil columns as influenced by interfacial (air-water) adsorption and water partitioning. VOCs [methylene chloride, tetrachloroethene (PCE), 1,1,1-trichloroethane (TCA), ethyl-benzene, p-xylene, chlorobenzene] with different water-partitioning and interfacial adsorption coefficients (air-water) were used to evaluate the theoretical basis of using these coefficients to predict the retardation factors (Rt) observed during gaseous transport. A loamy sand from Dover Air Force Base, DE, and a commercial sand were used as the column packing material to assess the effect of grain size on the air-water interfacial area (ai) and retardation at different water saturations (Sw). The ai were measured using n-alkanes. At low Sw, interfacial adsorption contributed most to the retardation for all VOCs during gaseous transport in the Dover soil which has little sorption capacity for the VOCs. As Sw increased, the fraction of Rt attributed to interfacial adsorption decreased, while that due to water partitioning increased for all of the VOCs used for this study. For the sand, with a more uniform grain-size distribution than the Dover soil, the contribution of air-water interfacial adsorption to the Rt of a VOC (p-xylene) was not as significant as that for the Dover soil due to small ai. The fractions of Rt attributed to interfacial adsorption and water partitioning were quantified. The observed Rt for the VOCs agreed well with those predicted based on the sorption coefficients and the quantities of sorption domains (Sw, ai).

Adsorption↗
PubMed2001

Coil occlusion of patent ductus arteriosus associated with right aortic arch.

Two children with patent ductus arteriosus and associated right aortic arch underwent successful transcatheter coil occlusion. Recognition of ductal anatomy and ensuring that no symptomatic vascular ring is present are important prior to embarking on ductal occlusion. It is concluded that coil occlusion of patent ductus arteriosus in association with right aortic arch is feasible, safe, and effective.

Abnormalities, Multiple↗
PubMed2001

Platypnea-orthodeoxia: management by transcatheter buttoned device implantation.

Dyspnea and arterial desaturation on upright position in elderly subjects is described as platypnea-orthodeoxia syndrome (POS) and in some patients it is due to right-to-left shunt across the atrial septal defect (ASD)/patent foramen ovale (PFO). Surgical closure of ASD/PFO has been the only available treatment option. Buttoned device has been used for occlusion of ostium secundum ASD, PFO associated with presumed paradoxical embolism and cerebrovascular accidents and ASD/PFO in association with other congenital heart defects causing right-to-left shunt. The objective of this article is to describe the use of buttoned device in effectively occluding ASD/PFO to relieve hypoxemia of POS. During a 4-year period ending January 2000, 10 patients, ages 71 +/- 9 (range 60-83) years with POS underwent buttoned device closure of their ASD/PFO. Echocardiographic and balloon-stretched atrial defect sizes were 8 +/- 3 mm and 12 +/- 3 mm, respectively. The ASD/PFO were occluded with devices ranging in size from 25 to 40 mm delivered via 9 French, long, blue Cook sheaths; eight had an additional 25- or 35-mm occluder placed on the right atrial side. The oxygen saturation increased (P < 0.001) from 76 +/- 7% (range 69-86%) to 95 +/- 2% (range 92-98%). No complications were encountered. Relief of symptoms was seen in all patients. Follow-up of 1-36 months (median 12 months) revealed persistent improvement of symptoms. Buttoned device occlusion of ASD/PFO to relieve hypoxemia of POS is feasible, safe, and effective and is an excellent alternative to surgery. Cathet Cardiovasc Intervent 2001;54:77-82.

Aged↗
PubMed2001

Achalasia in siblings in infancy.

Achalasia is rare in children, more so familial. We report two siblings with familial achalasia who presented in their infancy with vomiting and failure to thrive. Achalasia can be misdiagnosed as upper gastrointestinal obstruction as happened in one of our siblings. Esophageal contrast roentgenography is diagnostic. Both the children were treated successfully by transabdominal esophagomyotomy with fundoplication.

Esophageal Achalasia↗
PubMed2001

99mTc labeled VIP analog: evaluation for imaging colorectal cancer.

Early and reliable diagnosis of colorectal cancer continues to be demanding and challenging. Colorectal cancer cells express Vasoactive Intestinal Peptide (VIP) receptors in high density. We have prepared a VIP analog (TP3654), labeled it with (99m)Tc, and evaluated it in experimental animals as an agent for imaging colorectal cancer. The tissue distribution of (99m)Tc-TP3654 has been compared with that of (111)In-DTPA-Octreotide and (99m)Tc-anti-CEA scan in nude mice bearing human colorectal cancer LS174T. Finally, pharmacokinetic and tissue distribution studies of (99m)Tc-TP3654 have been performed in four normal human volunteers. Data suggest that (99m)Tc-TP3654 can be prepared efficiently without loss of its receptor specificity and biological activity. Although the 24 hr tumor uptake of (99m)Tc-TP3654 in the animal model used was modest (0.21 +/- 0.07% I.D./g), the tissue distribution profile was more favorable than that of (111)In-DTPA-Octreotide or (99m)Tc-anti-CEA scan. Human studies indicated that (99m)Tc-TP3654 had no adverse effect in any subject. Within 24 hours, approximately 70% of the injected dose cleared through the kidneys, and approximately 20% through the hepatobiliary system. In these non-fasting volunteers hepatobiliary clearance was slow and in cancer patients tumor uptake was rapid. Data suggest that (99m)Tc-TP3654 is a promising agent for imaging colorectal cancer.

Colorectal Neoplasms↗