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Biomedical subjects

L Rao

Publications and source records attributed to L Rao.

At least 19 recordsLinked to original sources
PubMed2007

Vibrational spectroscopy studies of formalin-fixed cervix tissues.

Optical histopathology is fast emerging as a potential tool in cancer diagnosis. Fresh tissues in saline are ideal samples for optical histopathology. However, evaluation of suitability of ex vivo handled tissues is necessitated because of severe constraints in sample procurement, handling, and other associated problems with fresh tissues. Among these methods, formalin-fixed samples are shown to be suitable for optical histopathology. However, it is necessary to further evaluate this method from the point of view discriminating tissues with minute biochemical variations. A pilot Raman and Fourier transform infrared (FTIR) microspectroscopic studies of formalin-fixed tissues normal, malignant, and after-2-fractions of radiotherapy from the same malignant cervix subjects were carried out, with an aim to explore the feasibility of discriminating these tissues, especially the tissues after-2-fractions of radiotherapy from other two groups. Raman and FTIR spectra exhibit large differences for normal and malignant tissues and subtle differences are seen between malignant and after-2-fractions of radiotherapy tissues. Spectral data were analyzed by principal component analysis (PCA) and it provided good discrimination of normal and malignant tissues. PCA of data of three tissues, normal, malignant, and 2-fractions after radiotherapy, gave two clusters corresponding to normal and malignant + after-2-fractions of radiotherapy tissues. A second step of PCA was required to achieve discrimination between malignant and after-2-fractions of radiotherapy tissues. Hence, this study not only further supports the use of formalin-fixed tissues in optical histopathology, especially from Raman spectroscopy point of view, it also indicates feasibility of discriminating tissues with minute biochemical differences such as malignant and after-2-fractions of radiotherapy.

Cervix Uteri↗
PubMed2006

Genotypic analysis of invasive Streptococcus pneumoniae from Mali, Africa, by semiautomated repetitive-element PCR and pulsed-field gel electrophoresis.

As part of a large, ongoing study of invasive infections in pediatric patients in Bamako, Mali, 106 cases of invasive pneumococcal disease were identified from June 2002 to July 2003 (J. D. Campbell et al., Pediatr. Infect. Dis. J. 23:642-649, 2004). Of the 12 serotypes present, the majority of isolates were not contained in PCV7 (the 7-valent pneumococcal conjugate vaccine), including 1 isolate that was serotype 1, 12 isolates that were serotype 2, 58 isolates that were serotype 5, 7 isolates that were serotype 7F, and 1 isolate that was serotype 12F. To determine whether clonal dissemination of the predominant serotypes had taken place, genotyping was performed on 100 S. pneumoniae isolates by using two methods: pulsed-field gel electrophoresis (PFGE) of SmaI-digested genomic DNA, and the Bacterial Barcodes repetitive-element PCR (rep-PCR) method. Criteria for delineating rep-PCR genotypes were established such that isolates of different serotypes were generally not grouped together. The two methods were equally discriminatory within a given pneumococcal serotype. PFGE separated the isolates into 15 genotypes and 7 subtypes; rep-PCR separated isolates into 15 genotypes and 6 subtypes. Using either method, isolates within serotypes 2, 5, and 7 formed three large, separate clusters containing 1 genotype each. Both methods further distinguished related subtypes within serotypes 2 and 5. Interestingly, one of the PFGE subtypes of serotype 5 is indistinguishable from the Columbia(5)-19 clone circulating in Latin America since 1994. The data support that serotypes 2 and 5 were likely to be the result of dissemination of particular clones, some of which are responsible for invasive disease over a broad population range.

Adolescent↗
PubMed2004

Autofluorescence of oral tissue for optical pathology in oral malignancy.

Pulsed laser-induced-fluorescence studies of pathologically certified oral tissues are carried out at different excitations and time delays. Among the several excitations used, 325 nm produced noticeably different spectral profile for normal and malignant tissues. Extensive curve analysis was carried out in order to understand changes in biochemical composition of tissue based on spectral profiles. Curve resolution and principal component analysis (PCA) show that the fluorescence intensity changes from normal to malignant tissue samples are not completely explained in terms of simple collagen and NAD(P)H intensity changes. The spectra require at least five components to be fully accounted for. Several discrimination methodologies based on PCA and intensity differences between different emission peaks (resultant peaks of curve analysis) were also evaluated. The results obtained indicate PCA using Mahalanobis distance and spectral residual as discrimination parameters provides best discrimination and can be used for matching unknown samples to standard calibration sets. Intensity ratio of bound NAD(P)H to collagen seems to be more suitable for discrimination between normal and malignant oral tissue, compared to ratio of collagen to total intensity of all the other components together.

Fluorescence↗
PubMed2004

Effect of raloxifene and its interaction with human PTH on bone formation.

We studied the of effects raloxifene alone or in combination with human PTH (hPTH) 1-34 in mineralizing cultures of SaOS-2 cells. Raloxifene (10(-8)-10(-6) M) increased bone nodule formation in cultures of SaOS-2 cells when added intermittently from day 8 to day 17. A single 24-h treatment with 10(-8) M hPTH (1-34) at day 8 reduced the nodule area by 75.6% at day 17, and raloxifene added concomitantly with hPTH (1-34) reduced this inhibitory effect in a dose-dependent manner. Raloxifene also reduced the hPTH (1-34)-induced inhibition of alkaline phosphatase (ALP) activity. The 10-fold stimulation of c-fos mRNA expression by hPTH (1-34) was not influenced by raloxifene co-treatment. The protein kinase A (PKA) inhibitor 6-22 amide (1.7 nM) and the protein kinase C (PKC) inhibitor-bisindolylmaleimide 1 (10 nM) did not influence the separate effects of PTH and raloxifene on mineralized bone nodule formation. This is the first report on the interaction of PTH and raloxifene in an osteoblast culture system.

Alkaline Phosphatase↗
PubMed2002

Chromatographic separation and characterization of hydrolyzed Cr(III) species.

Both macroscale and microscale methods to separate hydrolyzed Cr(III) species from acidic to near-neutral pH solutions have been developed. The macroscale approach is based on ion exchange, and involves separating monomeric, dimeric, trimeric, tetrameric, and higher order Cr(III) oligomers from such solutions using a gradient elution with increasing cationic charge. With this approach, the concentration of a given fraction can be maximized, and complete resolution between these species can be achieved. In addition, complete recovery of Cr(III) from the column is achievable. For the microscale approach, capillary electrophoresis with indirect detection is used to isolate and uniquely identify the same smaller oligomers and a fraction of larger Cr(III) species that are not uniquely identified. Capillary electrophoresis also provides indirect structural information for the Cr(III) trimer, suggesting that it exists in a triangular configuration rather than as a linear species. These methods are described in detail, and possible applications are discussed.

Journal Article↗
PubMed2001

EXAFS studies of americium (III)-benzimidazole complex in ethanol.

The local structures of Am, Nd and Er-Benzimidazole (Biz) in solution were determined by EXAFS. The BIZ molecule coordinated to Am and Nd through two nitrogen atoms in a bidentate fashion. Two nitrogen atoms of BIZ ligated to Am and Nd with the bond distances R(Am-n) N=2.63A and R(Nd-N) = 2.65 A, respectively. The total coordination number of the Am BIZ complexes (at a molar ratio of metal ion to ligand of 1:20) was approximately 10 but that of Nd BIZ complex was approximately 9.

Journal Article↗
PubMed2001

Congenital cervical bronchogenic cyst.

A bronchogenic cyst is a rare developmental aberration that occurs in the paediatric age group. Over 50 cases of bronchogenic cysts have been reported in the literature. There is still a possibility of clinically misdiagnosing this condition as a more common congenital neck cyst like a branchial cyst. We report here the case of a 12-year-old female presenting with a neck swelling since birth who was diagnosed to have a bronchogenic cyst based on characteristic clinical and histopathological findings.

Bronchogenic Cyst↗
PubMed2001

Gene expression profiling of low selenium status in the mouse intestine: transcriptional activation of genes linked to DNA damage, cell cycle control and oxidative stress.

The essential trace mineral selenium (Se) has been shown previously to inhibit intestinal, prostate, lung and liver tumor development and associated mortality in both experimental animals and humans. Although Se is likely to be one of the most powerful cancer chemopreventive agents in the human diet, its mechanism of action is unknown. To better understand the biological consequences of alterations in Se status, the gene expression profile associated with low Se status in the intestine of C57Bl/6J mice was analyzed. Mice were fed either a high fat (14%), torula yeast-based, Se-deficient diet (<0.01 mg/kg) or the same diet supplemented with a high level of dietary Se (1 mg/kg, as seleno-L-methionine) for 90 d. Use of high density oligonucleotide arrays representing 6347 genes revealed that low Se status results in a differential gene expression pattern indicative of activation of genes involved in DNA damage, oxidative stress and cell cycle control, and a decrease in the expression of genes involved in detoxification. These results suggest that suboptimal intake of a single trace mineral can have broad effects on gene expression patterns, providing a framework for understanding the multiple beneficial effects of Se in cancer chemoprevention and human health.

Animals↗
PubMed2001

Global comparisons between contact and noncontact mapping techniques in the right atrium: role of cavitary probe size.

In the right atrium (RA) we globally investigated: (1) the properties of noncontact electrograms measured by multielectrode cavitary probes, (2) the features of endocardial electrograms computed from the noncontact probe electrograms, and (3) the impact of the probe size on both the noncontact and the computed electrograms. We deployed a custom catheter in the dog RA, which consisted of a cylindrical probe with 64 electrodes on its surface, for measuring noncontact cavitary electrograms, and a concentric endocardial basket carrying an additional array of 64 electrodes, for measuring contact endocardial electrograms (the "gold standard"). Both a 5-mm- and a 10-mm-diam probe (P5 and P10, respectively) were sequentially tested in the same RA of one dog. Unipolar electrograms from both the probe and the basket were simultaneously acquired during normal as well as during paced rhythms (n > or =24 protocols per probe). Boundary element method and numeric regularization were applied to compute endocardial electrograms at the basket electrode locations. We found that noncontact electrograms were attenuated and smoothed, and this effect was exaggerated with the small probe. Computed endocardial electrograms more accurately reconstructed important amplitude distribution and morphological features; peak-to-peak amplitude error, 35% for P5 and 34% for P10. Activation and spatial errors of computed endocardial electrograms were 8.8+/-6.8 ms and 5.1+/-6.1 mm for P5, respectively, and 6.0+/-5.5 ms and 3.2+/-4.4 mm for P10, respectively. In conclusion, global RA activation may be delineated directly from noncontact cavitary electrograms alone, but may be affected by volume attenuation, smoothing, and probe size. Accurate endocardial electrograms, however, can be successfully computed from noncontact electrograms acquired with small probes and be used to reconstruct both electrogram amplitude and detailed morphology.

Animals↗
PubMed2000

[Study of spontaneous echo contrast in patients with rheumatic mitral stenosis by transesophageal echocardiography].

Spontaneous echo contrast (SEC) is common in the areas of slow blood flow. This study was conducted to examine the correlation of SEC and left atrial appendage function, atrial fibrillation (Af) and thrombus in patients with rheumatic mitral stenosis. The transthoracic and multiplane transesophageal echocardiograms were performed on 117 patients(mean age 42.22 +/- 10.79 years). Left atrial size, left atrial appendage area, mitral valve area, left atrial appendage flow peak emphatic velocity and full velocity were measured. The presence of SEC and thrombus in the left atrium and appendage was noted. The results showed that among the patients, 57 had normal sinus rhythm, 60 had Af; 19 had thrombus, 98 had no thrombus; 71 had SEC and 46 had no SEC. Compared with the patients without SEC, the patients with SEC showed greater incidence of thrombus (28.76% vs 0, P < 0.05), higher rate of Af (69.01% vs 23.91%, P < 0.05), larger LAD (46.93 +/- 0.85 mm vs. 41.76 +/- 1.05 mm, P < 0.05), larger LAA area (8.06 +/- 0.32 cm2 vs 6.92 +/- 0.31 cm2, P < 0.05), smaller MVA area (1.07 +/- 0.23 cm2 vs 1.32 +/- 0.35 cm2, P < 0.05), lower LAA flow peak emphatic velocity (0.17 +/- 0.01 m/s vs 0.32 +/- 0.02 m/s, P < 0.05), and lower LAA full velocity (0.18 +/- 0.01 m/s vs 0.31 +/- 0.03 m/s, P < 0.05). These findings indicate that the presence of SEC is associated with significantly greater incidence of thrombus, higher rate of Af, larger LAD and LAA area, smaller MVA area, lower LAA flow peak emphatic velocity and full velocity. Atrial fibrillation, the diameter of left atrium and the area of mitral valve are independent predictors of SEC. SEC is significantly associated with LAA function and thrombus formation.

Adolescent↗
PubMed2000

[Transthoracic three-dimensional echocardiography for determination of left ventricular mass in patients with dilated cardiomyopathy].

This study was performed to compare left ventricular mass (LVM) measurement by one- (1D), two- (2D) and 3D echocardiography with magnetic resonance imaging (MRI) in patients with dilated cardiomyopathy (DCM). 36 patients with DCM underwent imaging by conventional 1D and 2D echocardiography as well as transthoracic 3D echocardiographic data acquisition. Also patients were imaged with cardiac MRI. LVM was determined. There was no significant correlation (r = 0.42, P > 0.05) for measuring LVM between 1D echocardiography and MRI in patients with DCM. A significant correlation was obtained between 2D echocardiography and MRI (r = 0.64, P < 0.01) and between 3D and MRI (r = 0.78, P < 0.01) in determination of LVM. Compared with 1D and 2D echocardiography, the 3D analysis achieved a significantly higher agreement with the MRI results (1D; 399.2 g, 2D: 285.9 g, 3D: 172.6 g versus MRI: 199.1 g). Interobserver variability was 5.1% for measuring LVM by 3D echocardiography. These results suggest that LVM of patients with DCM can be accurately determined by transthoracic 3D echocardiography and this method could be used in clinical practice.

Adolescent↗
PubMed1999

Parapharyngeal space mesenchymal chondrosarcoma in childhood.

A case of extra osseous mesenchymal chondrosarcoma occuring in the parapharyngeal space in a 7-year-old girl, is being presented for its rarity. It is a slow growing, locally aggressive tumour with a high incidence of local recurrence as well as distant metastasis. It is rare in the pediatric age group and rarer in the parapharyngeal space. It has a poor prognosis, the 5-year survival rate varies between 30 and 50%. Radical surgery is the treatment of choice. Radiotherapy and chemotherapy have an adjuvant role. More experience with this tumour is required to evaluate the most effective treatment. Current literature on this subject has been reviewed.

Child↗
PubMed1999

[Left ventricular remodeling after aortic valve replacement].

The aim of the study was the assessment of left ventricular (LV) systolic function and left ventricular mass following aortic valve replacement (AVR) due to aortic valve stenosis as well as the influence of regression of LV hypertrophy in patients with normal and impaired LV systolic function prior to surgery. 74 patients with severe aortic valve stenosis (29 female, 45 male, mean age 66 +/- 18 years) were divided into 2 groups according to LV ejection fraction (EF): Group 1 with EF > 50% (n = 40); Group 2 with EF < or = 50% (n = 34). Furthermore, patients were differentiated into a group A without (n = 53) and a group B with aortic regurgitation (< or = II degrees, n = 21). All patients were examined by transthoracic echocardiography before and 1 month after surgery. There was a significant decrease of LV enddiastolic and endsystolic volume indices following AVR in group 2 and group B. Patients with preoperatively lower EF (group 2) showed an increase in LV ejection fraction from 39 +/- 10% before AVR to 47 +/- 11% after AVR (p < 0.001), whereas patients with preoperative normal EF (group 1) showed a significant decrease in EF (from 62 +/- 8% to 57 +/- 10%, p < 0.05). Also patients with combined aortic valve disease before AVR had an increase of EF after surgery (from 45 +/- 14% to 56 +/- 14%, p < 0.03). There were significant decreases of interventricular septum thickness and LV posterior wall thickness in group 1 and group A, whereas a significant decrease of LV enddiastolic diameter index was noted only in group B. Improvement of the NYHA functional class could be demonstrated in group 2 from 2.8 +/- 0.7 before to 2.2 +/- 0.6 after AVR, as well as in group B from 2.9 +/- 0.7 before to 1.9 +/- 0.7 after surgery. In conclusion, patients with impaired LV function or combined aortic valve disease showed a significant improvement of left ventricular systolic function after AVR, while patients with normal LV function presented a slight decrease of EF. There was a significant regression of left ventricular muscle mass in all groups independent of the left ventricular functional status.

Adult↗
PubMed1999

[Determination of left ventricular mass by transthoracic three-dimensional echocardiography in patients with dilated cardiomyopathy].

Conventional echocardiographic methods of measuring left ventricular mass (LVM) are limited by assumptions of ventricular geometry and image plane positioning. Three-dimensional (3D) echocardiography offers a promising new approach for more accurate determination of LVM. This study was performed to compare LVM measurement by one- (1D), two- (2D), and 3D echocardiography with magnetic resonance imaging (MRI) in patients (pts) with dilated cardiomyopathy (DCM). 36 pts (age 18-74) with DCM underwent imaging by conventional 1D and 2D echocardiography as well as transthoracic 3D echocardiographic data acquisition. Also, pts were imaged with cardiac MRI. Due to echocardiographic and MRI quality and because of exclusion criteria's for MRI, it was not possible to accomplish each LVM determination method for each patient. LVM was determined by Devereux and area-length algorithm for the conventional echocardiography. 3D echocardiographic data was calculated after manual delineation of endo- and epicardial boundaries--slice by slice (5 mm)--in 3 perpendicular cut planes. LVM was determined by multiplying the myocardial volume by the specific density of the myocardium. To determine LVM in MRI, the even summation of slices method for myocardial volume measurement was used defined by the endo- and epicardium in short axis images. There was no significant correlation (r = 0.42) for measuring LVM between 1D echocardiography and MRI in pts with DCM. A significant correlation was obtained between 2D (r = 0.64, p < 0.01) echocardiography and MRI as well between 3D (r = 0.78, p < 0.01) and MRI in determination of LVM. Compared with 1D and 2D echocardiography, the 3D analysis achieved a significantly higher agreement with the results of the MRI (1D: 399.2 g, 2D: 285.9 g, 3D: 172.6 g versus MRI: 199.1 g). Interobserver variability was 5.1% for measuring LVM by 3D echocardiography (1D: 11.2%, 2D: 9.1%). In conclusion, in pts with DCM the determination of LVM was incompletely characterized by 1D and 2D echocardiography compared with results of MRI. The best correlation and high agreement for determination of LVM was obtained with 3D echocardiography compared with MRI.

Adolescent↗
PubMed1999

Influence of plant growth stage on the essential oil content and composition in Davana (Artemisia pallens wall.).

The influence of three plant growth stages (full emergence of flower heads, anthesis, and initiation of seed set) on the essential oil content and composition in Davana (Artemisia pallens Wall) was investigated over two successive seasons. The essential oil content was found to be higher at the full emergence of flower heads than at anthesis and initiation of seed set stages. The contents of davanone, the major constituent of davana oil, and linalool decreased while those of (Z)- and (E)-methyl cinnamate, (E)-ethyl cinnamate, bicyclogermacrene, davana ether, 2-hydroxyisodavanone, and farnesol increased from flower heads emergence stage to the initiation of seed set stage. These results support the general practice of harvesting the crop at full bloom stage. Five compounds, viz., (Z)- and (E)-methyl cinnamates, (Z)- and (E)-ethyl cinnamates, and geranyl acetate, were identified for the first time in davana oil.

Artemisia↗
PubMed1997

The E1B 19K protein associates with lamins in vivo and its proper localization is required for inhibition of apoptosis.

Expression of the E1B 19K protein is required to inhibit apoptosis induced by E1A during adenovirus infection and transformation. E1B 19K is homologous to Bcl-2 in function and the two proteins also share limited amino acid sequence homology. Consequently, the E1B 19K and Bcl-2 proteins bind to and inhibit the cellular death-inducing proteins Bax, Bak and Nbk/Bik. Both E1B 19K and Bcl-2 localize to membranes of the nucleus and the endoplasmic reticulum. In addition to membrane association, and unlike Bcl-2, the E1B 19K protein is found associated with intermediate filament proteins in the cytoplasm and the nuclear lamina and copurifies with the lamins both during infection and transformation. While a membrane targeting domain at the C-terminus of Bcl-2 ensures its proper localization, the mechanism by which the E1B 19K protein localizes is unknown. Not surprisingly, lamin A fragments were cloned from a yeast two-hybrid screen for E1B 19K-interacting proteins. The interaction was demonstrated in yeast and mammalian cells in vivo and in vitro and was unique and specific to E1B 19K, with no interaction evident between Bcl-2 and lamin A. Mutants of lamin A/C which localized inappropriately in the cytoplasm or nucleus but retained E1B 19K binding, interfered with the nuclear envelope and cytoplasmic membrane targeting of the E1B 19K protein. Improper localization impaired the ability of the E1B 19K protein to inhibit apoptosis. Thus, proper localization of the E1B 19K protein is required for its function and the interaction of the E1B 19K protein with lamin A/C may represent a means for nuclear envelope localization.

Adenovirus E1B Proteins↗
PubMed1997

Nasal endoscopy in chronic/recurring sinusitis.

One hundred cases of chronic/recurring sinusitis cases were studied endoscopically with 0 degree (4 mm) rigid endoscopes in combination with conventional X-ray and computed tomography to reveal the exact nature of pathology which were sometimes not possible by our routine examination. After identification of the cause, functional endoscopic sinus surgery (FESS) was performed for cure and relief of symptoms. Messerklinger's technique was followed with good results and with minimum surgical trauma. Their results were correlated. Complications with possible management and long term results were discussed.

Chronic Disease↗