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P Padmanabhan

Publications and source records attributed to P Padmanabhan.

At least 19 recordsLinked to original sources
PubMed2006

Going to scale with professional skilled care.

Because most women prefer professionally provided maternity care when they have access to it, and since the needed clinical interventions are well known, we discuss in their paper what is needed to move forward from apparent global stagnation in provision and use of maternal health care where maternal mortality is high. The main obstacles to the expansion of care are the dire scarcity of skilled providers and health-system infrastructure, substandard quality of care, and women's reluctance to use maternity care where there are high costs and poorly attuned services. To increase the supply of professional skilled birthing care, strategic decisions must be made in three areas: training, deployment, and retention of health workers. Based on results from simulations, teams of midwives and midwife assistants working in facilities could increase coverage of maternity care by up to 40% by 2015. Teams of providers are the efficient option, creating the possibility of scaling up as much as 10 times more quickly than would be the case with deployment of solo health workers in home deliveries with dedicated or multipurpose workers.

Africa South of the Sahara↗
PubMed2005

Study on Staphylococcus aureus strain HPC-250 for associated antibacterial property.

We isolated a Staphylococcus aureus strain HPC-250 producing antibacterial agent against Paenibacillus strain HPC-251. Both strains were isolated from the same environmental niche. The bacteria were identified using the partial sequencing of their TA-cloned 16S rDNA. Spectrum of the antibacterial agent was also tested against routine observed bacteria with drinking water contamination such as Escherichia coli, Salmonella, Pseudomonas, and Vibrio and these were found to be sensitive. Bacteria like Acinetobacter and Burkholderia were found to be resistant. The differential antibacterial activity of the HPC-250 was observed for the genus Bacillus where B. subtilis remained resistant although B. sphaericus was sensitive.

Acinetobacter↗
PubMed2005

Tin foil as bolus material for therapeutic electron beams from the Varian Clinac 2100C/D.

Tin foils of sub-millimetre thickness have been investigated as bolus material for therapeutic electron beams from the Varian Clinac 2100C/D linear accelerator. Measurements with ionisation chamber and radiographic film in Plastic Water or water were performed under tin foil bolus to determine surface dose, therapeutic ranges, output factor correction, penumbra and dose outside the field edge. Appropriate thicknesses of tin foil for 90% dose at the surface were found to be approximately 0.3 mm for 6 MeV, and 0.4 mm for 9 MeV and 12 MeV. Enhanced therapeutic interval with tin foil bolus over water-equivalent bolus has previously been reported, but was found not to be evident for 12 MeV and for a small (4 x 4 cm2) 9 MeV field. The penumbra width of fields with tin foil and water-equivalent bolus were found to be within 2 mm, while the doses at 1 cm outside the field edge were within 1.5% of peak dose. Output factor corrections for fields with tin foil were measured as within 2% of unity. Air gaps between the tin foil and phantom surface up to 5 mm were observed to have minimal effect on output correction factor, relative surface dose, and therapeutic range.

Dose-Response Relationship, Radiation↗
PubMed2003

Discovery of a bacterium, with distinctive dioxygenase, that is responsible for in situ biodegradation in contaminated sediment.

Microorganisms maintain the biosphere by catalyzing biogeochemical processes, including biodegradation of organic chemical pollutants. Yet seldom have the responsible agents and their respective genes been identified. Here we used field-based stable isotopic probing (SIP) to discover a group of bacteria responsible for in situ metabolism of an environmental pollutant, naphthalene. We released 13C-labeled naphthalene in a contaminated study site to trace the flow of pollutant carbon into the naturally occurring microbial community. Using GC/MS, molecular biology, and classical microbiological techniques we documented 13CO2 evolution (2.3% of the dose in 8 h), created a library of 16S rRNA gene clones from 13C labeled sediment DNA, identified a taxonomic cluster (92 of 95 clones) from the microbial community involved in metabolism of the added naphthalene, and isolated a previously undescribed bacterium (strain CJ2) from site sediment whose 16S rRNA gene matched that of the dominant member (48%) of the clone library. Strain CJ2 is a beta proteobacterium closely related to Polaromonas vacuolata. Moreover, strain CJ2 hosts the sequence of a naphthalene dioxygenase gene, prevalent in site sediment, detected before only in environmental DNA. This investigative strategy may have general application for elucidating the bases of many biogeochemical processes, hence for advancing knowledge and management of ecological and industrial systems that rely on microorganisms.

Bacteria↗
PubMed2003

Respiration of 13C-labeled substrates added to soil in the field and subsequent 16S rRNA gene analysis of 13C-labeled soil DNA.

Our goal was to develop a field soil biodegradation assay using (13)C-labeled compounds and identify the active microorganisms by analyzing 16S rRNA genes in soil-derived (13)C-labeled DNA. Our biodegradation approach sought to minimize microbiological artifacts caused by physical and/or nutritional disturbance of soil associated with sampling and laboratory incubation. The new field-based assay involved the release of (13)C-labeled compounds (glucose, phenol, caffeine, and naphthalene) to soil plots, installation of open-bottom glass chambers that covered the soil, and analysis of samples of headspace gases for (13)CO(2) respiration by gas chromatography/mass spectrometry (GC/MS). We verified that the GC/MS procedure was capable of assessing respiration of the four substrates added (50 ppm) to 5 g of soil in sealed laboratory incubations. Next, we determined background levels of (13)CO(2) emitted from naturally occurring soil organic matter to chambers inserted into our field soil test plots. We found that the conservative tracer, SF(6), that was injected into the headspace rapidly diffused out of the soil chamber and thus would be of little value for computing the efficiency of retaining respired (13)CO(2). Field respiration assays using all four compounds were completed. Background respiration from soil organic matter interfered with the documentation of in situ respiration of the slowly metabolized (caffeine) and sparingly soluble (naphthalene) compounds. Nonetheless, transient peaks of (13)CO(2) released in excess of background were found in glucose- and phenol-treated soil within 8 h. Cesium-chloride separation of (13)C-labeled soil DNA was followed by PCR amplification and sequencing of 16S rRNA genes from microbial populations involved with (13)C-substrate metabolism. A total of 29 full sequences revealed that active populations included relatives of Arthrobacter, Pseudomonas, Acinetobacter, Massilia, Flavobacterium, and Pedobacter spp. for glucose; Pseudomonas, Pantoea, Acinetobacter, Enterobacter, Stenotrophomonas, and Alcaligenes spp. for phenol; Pseudomonas, Acinetobacter, and Variovorax spp. for naphthalene; and Acinetobacter, Enterobacter, Stenotrophomonas, and Pantoea spp. for caffeine.

Bacteria↗
PubMed2002

Geochemical and physiological evidence for mixed aerobic and anaerobic field biodegradation of coal tar waste by subsurface microbial communities.

We used geochemical analyses of groundwater and laboratory-incubated microcosms to investigate the physiological responses of naturally occurring microorganisms to coal-tar-waste constituents in a contaminated aquifer. Waters were sampled from wells along a natural hydrologic gradient extending from uncontaminated (1 well) into contaminated (3 wells) zones. Groundwater analyses determined the concentrations of carbon and energy sources (pollutants or total organic carbon), final electron acceptors (oxygen, nitrate, sulfate), and metabolic byproducts (dissolved inorganic carbon [DIC], alkalinity, methane, ferrous iron, sulfide, Mn2+). In the contaminated zone of the study site, concentrations of methane, hydrogen, alkalinity, and DIC were enhanced, while dissolved oxygen and nitrate were depleted. Field-initiated biodegradation assays using headspace-free serum bottle microcosms filled with groundwater examined metabolism of the ambient organic contaminants (naphthalene, 2-methylnaphthalene, benzothiophene, and indene) by the native microbial communities. Unamended microcosms from the contaminated zone demonstrated the simultaneous degradation of several coal-tar-waste constituents at the in situ temperature (10 degrees C). Lag phases prior to the onset of biodegradation indicated the prevalence of both aerobic and anaerobic conditions in situ. Electron acceptor-amended microcosms from the most contaminated well waters demonstrated only aerobic naphthalene degradation. Collectively, the geochemical and microbial evidence show that biodegradation of coal-tar-waste constituents occurs via both aerobic and anaerobic terminal electron accepting processes at this site.

Bacteria, Aerobic↗
PubMed2002

Corneal topography and Schirmer testing in eyes with the Hudson-Stahli line.

PURPOSE: To evaluate corneal topographic features and tear secretion in eyes with the Hudson-Stahli line. METHODS: Keratometry, computerized videokeratography and Schirmer testing were performed in 50 cases with bilateral Hudson-Stahli line, and 55 controls without the Hudson-Stahli line. Similar tests were performed in 21 subjects with unilateral Hudson-Stahli line. RESULTS: Corneal topographic features and keratometry in the horizontal meridian were similar in cases and controls, and in fellow eyes of subjects with unilateral Hudson-Stahli line. Keratometry in the vertical meridian in cases (43.01 +/- 2.01) was significantly lesser than in controls (43.94 +/- 1.77) (P = 0.01). This value was not different in fellow eyes of patients with unilateral Hudson-Stahli line. Schirmer testing revealed significantly greater tear secretion in cases (16.72 +/- 4.99 mm) compared to controls (12.57 +/- 3.62 mm) (P < 0.01). In subjects with unilateral Hudson-Stahli line, mean Schirmer values in the eye with the line (17.52 +/- 6.86 mm) were significantly greater than in eyes without (13.67 +/- 4.64 mm) (P = 0.04). CONCLUSION: Formation of the Hudson-Stahli line may be dependent on the presence of normal tear secretion in the eye.

Adult↗
PubMed2001

Interface fluid after laser in situ keratomileusis.

We report a case in which raised intraocular pressure (IOP) was associated with interface fluid after uneventful bilateral laser in situ keratomileusis (LASIK). The patient presented with diffuse lamellar keratitis in both eyes 3 weeks postoperatively that was treated aggressively with topical corticosteroids. A steroid-induced rise in IOP resulted in interface fluid accumulation and microcystic edema. Measurements with the Goldmann tonometer revealed an IOP of 3.0 mm Hg in both eyes. However, Schiotz tonometry recorded a pressure of 54.7 mm Hg in both eyes. Reduction in the dosage of topical corticosteroid and medical treatment of the raised IOP resulted in resolution of the microcystic edema and interface fluid accumulation. This case highlights the inaccuracies of IOP measurement after LASIK and the resulting complications.

Administration, Topical↗
PubMed2000

In situ tumbling of the AcrySof intraocular lens.

The small incision through which foldable acrylic intraocular lenses (IOLs) are implanted does not allow easy explantation of the lens in the event of intraoperative complications. Reversal of the IOL optic during insertion, although rare, can predispose to postoperative complications such as pupillary capture of the IOL, capsule bag distension syndrome, and refractive problems. Explanting the IOL can damage it, the cataract wound, or both. We describe a technique of in situ tumbling of the AcrySof IOL to correct reversed-optic implantation that preserves the integrity of the IOL and anterior segment structures.

Acrylic Resins↗
PubMed2000

Bilateral corneal infiltrates after excimer laser photorefractive keratectomy.

A 26-year-old man developed painless inferior subepithelial infiltrates away from the site of ablation in both eyes after excimer laser photorefractive keratectomy (PRK) for myopia. Clinical characteristics of the corneal infiltrates resembled staphylococcal-immune infiltrates. The condition responded to treatment with topical diluted steroids and antibiotics. There was no residual corneal scarring. The infiltrates did not affect the refractive outcome of the surgery. Recognition of this rare entity will help clinicians avoid aggressive investigative and treatment modalities that can affect the results of PRK.

Adult↗
PubMed2000

Duplex RT-PCR for simultaneous detection of hepatitis A and hepatitis E virus isolated from drinking water samples.

A duplex reverse transcription polymerase chain reaction (RT-PCR) protocol for simultaneous detection of hepatitis A virus (HAV) and hepatitis E virus (HEV) in water samples has been developed and demonstrated. Both HAV and HEV were concentrated from drinking water samples through a one-step concentration protocol. Different cDNA could be produced in the RT step carried out with a random primer in a single reaction tube. Two different sets of primers specific for HAV-cDNA and HEV-cDNA were used for PCR amplification. Amplified DNA products representing HAV and HEV were identified by gel electrophoresis at 247 and 327 bp (base pair) sequences, respectively. Specific sets of primers amplified a single type of virus and no cross-reactivity of the primers was noticed in duplex RT-PCR. The protocol was used for direct isolation and detection of HAV and HEV from 23 water samples in urban areas of Chennai city. Out of these, nine water samples were positive for HAV, and three for HEV. All three samples positive for HEV were also positive for HAV. The test provides a rapid and economical means of water quality surveillance to specifically detect HAV and HEV.

Cities↗
PubMed2000

Corneal endothelial cell density and morphology in normal Indian eyes.

PURPOSE: To describe corneal endothelial cell density and morphology in the Indian population and to compare endothelial cell characteristics in the Indian population with data available in literature for American and Japanese populations. METHODS: Specular microscopy and corneal pachymetry were performed in both eyes of 537 normal Indian volunteers, aged 20-87 years. Parameters studied included endothelial cell density, cell area, coefficient of variation (CV) in cell area and hexagonality. RESULTS: Mean endothelial cell density in the study population was 2,525 +/- 337 cells/mm2. There was a statistically significant decrease in endothelial cell density with age (p < 0.001, correlation -0.387) and the rate of cell loss was 0.3% per year. There was also a statistically significant increase in mean cell area (p < 0.001, correlation 0.362) and CV (p = 0.02, correlation 0.096), and decrease in percentage of hexagonal cells (p = 0.01, correlation -0.127) with increasing age. There was no significant difference in these parameters between fellow eyes of subjects. In all age groups, the mean endothelial cell density was significantly lower than values reported previously in the Japanese population. The values were less than those described in the American population, but the differences were statistically significant only in the 20-30 and 41-50 year age groups. CONCLUSION: Normative data for the endothelium in the Indian population are reported. Endothelial cell density in Indian eyes is less than the values described in the Japanese and American populations.

Adult↗
PubMed2000

Understanding corneal topography.

With the increase in corneal laser refractive surgery, there is a greater need for precise evaluation of the corneal surface. Articles published in the past year have reported possible use of confocal scanning laser technology-based devices to image the cornea. Other studies have compared existing instruments and software in an effort to determine if data from different instruments are comparable. Topographic evaluation also has served to highlight long-term complications of procedures like radial keratotomy and the promise of newer surgical procedures like the intrastromal corneal ring segments. Studies of the corneal surface have helped refine surgical procedures like photorefractive keratectomy, laser in situ keratomileusis, penetrating keratoplasty, and cataract surgery. Topographic measures that serve as direct correlates of ocular visual performance, however, still remain elusive. Studies in the past year have confirmed that corneal topographic evaluation may be a powerful tool in the search for a genetic basis of keratoconus. Important areas for future research include precise determination of the power of the postrefractive surgery cornea to allow precise estimation of intraocular lens power in these eyes. Detecting the presence of past corneal refractive surgery in donor eyes also is likely to be a challenge. Despite the numerous advances in the field of corneal topography in the past year, there is still a need to present the data in a standardized format that is universal to all instruments and technologies.

Cornea↗