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Biomedical subjects

R Prasad

Publications and source records attributed to R Prasad.

At least 19 recordsLinked to original sources
PubMed2006

Effect of DC/mDC iontophoresis and terpenes on transdermal permeation of methotrexate: in vitro study.

The systemic toxicity caused by methotrexate limits its use and transdermal delivery would be a possible alternative. Transdermal permeation of methotrexate loaded into polyacrylamide-based hydrogel patch, across mice skin was studied in vitro after pretreatment with terpenes and ethanol, alone or in combination with iontophoresis (DC/mDC). Polyacrylamide patches gave the maximum flux as compared to the copolymers of acrylamide and acrylic acid. Of the terpenes used, pure menthol showed maximum enhancement (38%), whereas pure limonene elicited a minimum of 9.9% enhancement. Binary combination of menthol and ethanol increased the permeation to 54.9%, which was further enhanced to 93.69% and 117% when used in combination with DC and square wave (mDC) iontophoresis, respectively. ATR-FTIR of the stratum corneum treated with terpenes showed a split in the asymmetric C-H stretching vibrations along with decrease in peak heights and areas of asymmetric, symmetric C-H stretching, C=O stretching and amide bands. A split in amide II band was observed with iontophoresis. ATR-FTIR studies suggest conformational changes in the lipid-protein domains thereby increasing permeation. Histopathological studies on treated skin samples, gave an insight about the anatomical changes brought by the application of various enhancers. Binary mixture of menthol and ethanol in combination with square wave gave best results.

Acrylic Resins↗
PubMed2006

Molecular cloning and functional characterization of novel zinc transporter rZip10 (Slc39a10) involved in zinc uptake across rat renal brush-border membrane.

Previously, in our laboratory a 40-kDa zinc transporter protein was purified and functionally reconstituted in proteoliposomes (Kumar R, Prasad R. Biochim Biophys Acta 1419: 23-32, 1999). Furthermore, we now report the identification of Slc39a10 cDNA encoding the 40-kDa zinc transporter protein by isolating a cloned DNA complementary to zinc transporter mRNA. cDNA was constructed from immunoenriched mRNA encoding the zinc transporter. cDNA was inserted into pBR322 using poly(dC)- poly(dG) tailing. Escherichia coli DH5alpha cells were transformed, and colonies were screened for zinc transporter cDNA by insertional inactivation. Plasmid DNA was purified from the ampicillin-sensitive clones, and the cDNA was sequenced from both strands. A basic local alignment research tool (BLAST) search of cDNA revealed that it belongs to the Slc39 gene family of zinc transporters and was designated as Slc39a10. Zinc transporter protein deduced on the basis of cDNA sequence was named rZip10 and consists of 385 amino acids with 9 predicted transmembrane domains. The Slc39a10 gene was abundantly expressed in both rat and human tissues. Increased extracellular zinc concentration resulted in upregulation of Slc39a10 in LLC-PK(1) cells expressing rZip10, which was downregulated at higher zinc concentrations. These cells accumulated more zinc than control cells. rZip10-mediated zinc uptake activity was time-, temperature-, and concentration-dependent and saturable which followed Michaelis-Menten kinetics with a K(m) of 19.2 microM and V(max) of 50 pmol x min(-1) x mg protein(-1). This activity was competitively inhibited by cadmium with K(i) of 91 microM. rZip10-mediated zinc uptake was inhibited by COOH group-modifying agents such as DCC. Immunofluorescence studies showed that rZip10 localizes to the plasma membrane of LLC-PK(1) cells.

Amino Acid Sequence↗
PubMed2006

Evaluation of polymerase chain reaction and adenosine deaminase assay for the diagnosis of tuberculous effusions in children.

AIM: To evaluate and compare the utility of polymerase chain reaction (PCR) for the diagnosis of tuberculous effusions in children. METHODS: PCR, adenosine deaminase (ADA) activity and absolute lymphocyte count (ALC) were evaluated in the fluid of 31 tuberculous (20 pleural, 8 ascites and 3 pericardial) and 24 non-tuberculous (10 transudtative ascites, 8 empyema thoracis, 3 malignant pleural and 3 pyopericardium) effusions. RESULTS: Fluid PCR for Mycobacterium tuberculosis was positive in 74% of tuberculous effusions, whereas it was falsely positive in 13% of the non-tuberculous group. The mean fluid ADA and ALC values were significantly higher in tuberculous effusions than in non-tuberculous effusions (p<0.001). The sensitivity and specificity of PCR, ADA (> or =38 IU/l) and ALC (> or =275/mm3) were 74% and 88%, 81% and 75%, and 90% and 83%, respectively, in diagnosing tuberculous effusions. The sensitivity of PCR, ADA and ALC was 100%, 100% and 88%, respectively, for confirmed tuberculous effusions. When the two tests were combined (either/or positive), the sensitivity increased (90-100%) at the expense of specificity. When both the tests were positive, then the specificity markedly increased (92-96%), but sensitivity of the tests decreased. CONCLUSION: Fluid PCR alone should not be relied on as a single test; rather, combined analysis with either ADA or ALC could be more useful in the diagnosis of tuberculous effusions in children.

Adenosine Deaminase↗
PubMed2006

Effect of inclusion of tree leaves in feed on nutrient utilization and rumen fermentation in sheep.

The effect of inclusion of tree leaves in mustard (Brassica campestris) straw (MS) based complete feed blocks (CFB) on nutrient utilization and rumen fermentation was studied in adult male sheep. Four types of CFB diets (Roughage:Concentrate:Molasses, 70:25:5) were prepared. The compaction process increased bulk density (g/cm(3)) of MSB, MSNL, MSSL and MSAL by 2.9, 1.79, 2.40 and 2.26 times, respectively. The dry matter intake (g/day) was higher (P<0.05) in MSSL and MSAL than in MSB. Digestibility coefficients of crude protein and hemicellulose increased (P<0.05) due to inclusion of tree leaves, while digestibility of dry matter and organic matter showed small improvement. However, inclusion of tree leaves did not affect digestibility of neutral detergent fibre, cellulose and energy. The concentration of total volatile fatty acids in rumen was significantly higher in MSAL than in MSB or MSSL. Blood bio-chemical parameters were within the normal physiological range in all the groups.

Animal Feed↗
PubMed2006

Bipaddle pectoralis major myocutaneous flap in reconstructing full thickness defects of cheek: a review of 47 cases.

We present a series of reconstruction of 47 patients with large full thickness cheek defects secondary to cancer ablative surgery. All patients were reconstructed primarily by bipaddle pectoralis major myocutaneous (PMMC) flap. The age of patients ranged from 25 to 85 years (mean 49.5 years). All patients were male. The size of the paddle used for mucosal defect repair ranged from 5 x 3 to 9 x 7 cm and the size of the paddle used for skin cover ranged from 4 x 4 to 9 x 8 cm. The total flap size ranged from 10 x 5 to 17 x 7 cm. One patient had complete loss of flap (2.12%). Sixteen patients had minor complications all of which settled with conservative management. The follow up period varied from 1 month to 4 years. The modification adopted in bipaddling the flap was based on anatomical location of perforators to ensure good blood supply to both paddles of flap. Placing the flap horizontally with inclusion of nipple and areola increased the reach and size of available flap. We found the technique to be anatomically sound, technically easy and reliable. Precautions taken included proper assessment of reach of the paddle, placing not more than one-third of the paddle outside the muscle and securing the skin paddle to the muscle to avoid shearing of perforators during flap raising. We conclude that this technique is a useful alternative where microsurgical free tissue transfer is not possible or as a salvage procedure in selected large full thickness oral cavity lesions. However, the disadvantages of this method include loss of nipple and areola and technical difficulty in obese patients and females.

Adult↗
PubMed2006

Anti-dsDNA and anti-Sm antibodies do not predict damage in systemic lupus erythematosus.

We aimed to determine whether anti-dsDNA and anti-Sm antibodies predict damage in systemic lupus erythematosus (SLE). Five-hundred inception patients from the University of Toronto Lupus Clinic were studied. Predictors assessed for the entire study period were: (1) raised anti-dsDNA on two consecutive occasions; (2) anti-dsDNA levels (normal, mildly or highly elevated); (3) presence of antiSm on any occasion. To account for disease duration, the following were assessed at three years post-inception: raised anti-dsDNA on two consecutive occasions; anti-dsDNA levels. These predictors were correlated with the following outcomes: (1) overall SLICC/ACR Damage Index (SDI) at the end of the study period; (2) frequency of damage in the cardiovascular, neuropsychiatric, musculoskeletal and renal components of SDI; ((3) SDI at five years for the predictors assessed at three years post-inception. In the multivariate analysis, presence of anti-DNA antibodies or of anti-SM were non-significant but sex, age at SLE diagnosis, disease duration, corticosteroid use and cumulative dose were strong predictors of damage. Raised anti-dsDNA on two occasions or anti-dsDNA levels in the three years post-inception patients did not predict damage at five years. The presence and levels of anti-dsDNA and anti-Sm antibodies do not predict damage in SLE.

Adrenal Cortex Hormones↗
PubMed2006

Efflux pumps in drug resistance of Candida.

The incidences of human pathogenic yeast Candida albicans and its related species acquiring resistance to antifungals have increased considerably, which poses serious problems towards its successful chemotherapy. The resistance of these pathogenic fungi is not restricted to the commonly used triazole compounds but is even encountered, though not often, with polyene derivatives as well. The efflux pump proteins belonging to ABC (ATP Binding Cassette) and MFS (Major Facilitators) super family are the most prominent contributors of multidrug resistance (MDR) in yeasts. The abundance of the drug transporters and their wider specificity suggest that these transporters may not be exclusively drug exporters in yeasts and may have other cellular functions. In this article we focus on some of the recent advances on the structure and function, evolution and transcriptional control of drug efflux proteins of Candida. A short discussion on the physiological relevance of drug transporters is also included.

ATP-Binding Cassette Transporters↗
PubMed2005

Ectopic expression of alkaline phosphatase in proximal tubular brush border membrane of human renal cell carcinoma.

The present study was conducted to find out any alteration in the expression and activity of alkaline phosphatase in the brush border membrane (BBM) from renal cell carcinoma (RCC) in comparison to normal renal BBM. The specific activity of alkaline phosphatase was drastically reduced in homogenate as well as BBM from RCC kidney when compared to ALP activity in BBM of normal kidney. Kinetic studies revealed that diminished activity of alkaline phosphatase in BBM isolated from RCC was fraternized with decrease in maximal velocity (V(max)) and increase in affinity constant (K(m)) of the enzyme. SDS-PAGE studies showed that the BBM proteins having molecular weights ranging from 95 to 170 kDa were poorly expressed in RCC BBM in relative to normal kidney BBM. Incubation of SDS-PAGE gel with BCIP/NBT dye clearly showed that the expression of ALP in tumor renal BBM was markedly reduced as compared to normal kidney. Further, Western blot analysis using anti-alkaline phosphatase antibody also confirmed the reduced expression of ALP in tumor renal BBM. Lipid composition in reference to phospholipids, glycolipids and cholesterol in tumor renal BBM was altered to that of normal renal BBM, indicating alteration in membrane fluidity of tumor renal BBM.

Adult↗
PubMed2005

Fatal haemothorax following large-bore percutaneous cannulation before liver transplantation.

Percutaneous bypass catheters are routinely used for veno-venous bypass (VVBP) during orthotopic liver transplantation (OLT). The recognized risks include bleeding, injury of vascular and nerve structures and lymphatic leakage. We describe a case where there were difficulties during catheterization and the patient suffered a cardiac arrest on commencing VVBP. Post-mortem examination revealed the bypass catheter tip in the pleural space and a large right haemothorax. Possible mechanisms of vascular perforation and preventative measures are discussed.

Catheterization, Central Venous↗
PubMed2005

Two-year experience with minimally invasive herniorrhaphy in children.

BACKGROUND: Laparoscopic herniorrhaphy in pediatrics is rarely performed. We evaluated our 2-year experience of minimally invasive inguinal herniorrhaphy in children. METHODS: All procedures were performed under general anesthesia using <2-mm instruments and scopes and a surgical awl to accomplish high ligation of the hernia sac under direct vision. RESULTS: A total of 90 consecutive children (76 males and 14 females) older than the age of 6 months underwent a minimally invasive herniorrhaphy (60 unilateral and 30 bilateral; total of 120 hernias repaired). Seventeen children underwent herniorrhaphy in conjunction with another procedure. All children who underwent herniorrhaphy alone were discharged immediately and allowed unrestricted activity. Only four patients requested a narcotic analgesic. There was one recurrence early in the series (0.83%), prompting a change in technique. CONCLUSIONS: Minimally invasive inguinal herniorrhaphy in children is a safe alternative for the experienced pediatric laparoscopist. There is a similar recurrence rate as that of the traditional open approach with a superior cosmetic result.

Adolescent↗
PubMed2005

Thyroid hormones increase Na+-Pi co-transport activity in intestinal brush border membrane: role of membrane lipid composition and fluidity.

In the present study, we documented the promising role of thyroid hormones status in animals in modulation of Na+-Pi transport activity in intestinal brush border membrane vesicles (BBMV) which was accompanied with alterations in BBM lipid composition and fluidity. Augmentation of net Pi balance in hyperthyroid (Hyper-T) rats was fraternized with accretion of Pi transport across BBMV isolated from intestine of Hyper-T rats as compared to hypothyroid (Hypo-T) and euthyroid (Eu-T) rats while Na+-Pi transport across BBMV was decreased in Hypo-T rats relative to Eu-T rats. Increment in Na+-Pi transport in intestinal BBMV isolated from Hyper-T rats was manifested as an increase in the maximal velocity (Vmax) of Na+-Pi transport system. Furthermore, BBMV lipid composition profile in intestinal BBM from Hyper-T was altered to that of Hypo-T rats and Eu-T rats. The molar ratio of cholesterol/phospholipids was higher in intestinal BBM from Hypo-T rats. Fluorescence anistropy of diphenyl hexatriene (rDPH) and microviscosity were significantly decreased in the intestinal BBM of Hyper-T rats and decreased in Hypo-T rats as compared to Eu-T rats which corroborated with the alteration in membrane fluidity in response to thyroid hormone status of animals. Therefore, thyroid hormone mediated change in membrane fluidity might play an important role in modulating Na+-Pi transport activity of intestinal BBM.

Animals↗
PubMed2005

Phospholipase-C sensitive GPI-anchored proteins of goat sperm: possible role in sperm protection.

The role of glycosylphosphatidylinositol (GPI)-anchored sperm proteins in reproduction has been investigated. SDS-polyacrylamide gels (PAGE) analysis of goat sperm (Capra indica) indicated that several GPI-anchored proteins were released by phosphatidylinositol-specific phospholipase-C (PI-PLC) treatment. The distribution of this category of PI-PLC-sensitive GPI-anchored proteins on the surface of sperm was examined by indirect immunofluorescence. The fluorescence microscopic study clearly demonstrated that the PI-PLC-sensitive GPI-anchored proteins are confined predominantly to the head region of goat sperm. Further experiments were conducted on intact and PI-PLC treated sperm in order to decipher the function of GPI proteins. Co-incubation of sperm with peritoneal macrophages led to the enhanced phagocytosis of PI-PLC treated sperm by macrophages compared with the untreated intact sperm. Transmission electron micrographs of the macrophages acquired from the phagocytosis assay are provided to corroborate the same. From the results obtained it is inferred that one or more of the PI-PLC-sensitive GPI-anchored proteins on the sperm surface could act as protection factor(s) that shield the sperm from macrophages.

Animals↗
PubMed2005

Measurement and analysis of cross sections for (p,n) reactions in 51V and 113In.

Excitation functions (EFs) for the reactions 51V(p,n)51Cr up to 15 MeV and 113In(p,n)113Sn up to 20 MeV from threshold have been measured employing the stacked foil activation technique. To the best of our knowledge EF for the reaction 113In(p,n)113Sn has been reported for the first time. The theoretical analysis of the EFs has been done employing both the semi-classical as well as quantum mechanical codes which include compound nucleus and pre-equilibrium (PE) emission into consideration. In general, theoretical calculations agree well with the experimental data. Effect of various free parameters used in the calculations have also been discussed. A significant contribution of pre-equilibrium component has been observed at these energies.

Journal Article↗
PubMed2005

Membrane raft lipid constituents affect drug susceptibilities of Candida albicans.

By exploiting the biosynthetic pathways of raft lipid constituents, in this study we demonstrate that fluctuations in either sphingolipid or ergosterol levels result in increased drug sensitivity and morphological defects in Candida albicans cells. We show that any change in either ergosterol composition by conditionally disrupting ERG1 or in sphingolipid composition by homozygously disrupting its biosynthetic gene IPT1 leads to improper surface localization of a major ABC (ATP-binding cassette) drug efflux protein, Cdr1p. Results suggest that sterol/sphingolipid-rich membrane microdomains play an important role in positioning and functional maintenance of the integral efflux protein. The impaired ability of erg1/ipt1 mutant cells to efflux drugs mediated through Cdr1p appears to be the main cause of increased drug sensitivity of Candida cells.

Antifungal Agents↗
PubMed2004

COX-2 expression is associated with an aggressive phenotype in ductal carcinoma in situ.

Cyclooxygenase type-2 (COX-2) is overexpressed in malignant tumours including breast cancers, though the mechanism of upregulation is unclear. This study aimed to determine COX-2 expression in ductal carcinoma in situ (DCIS) in comparison to invasive breast cancer (IBC) and normal breast, and also to investigate the relationship of COX-2 expression with HER-2 expression, oestrogen receptor (ER), tumour grade and cellular proliferation (Ki67) in DCIS. Cyclooxygenase type-2, HER-2, ER and Ki67 expression were determined by immunohistochemistry on paraffin tissue sections of DCIS (n=187), IBC (n=65) and normal breast reduction tissue (n=60). Cyclooxygenase type-2 expression in DCIS (67%, P<0.001) and IBC (63%, P<0.001) was significantly greater than in normal breast (23%). There was no difference in COX-2 expression level between DCIS and IBC (P=0.87) or between normal breast from reduction mammoplasty tissue and normal breast ducts around DCIS (22%, P=0.29). In DCIS, COX-2 expression was associated with higher cellular proliferation rates (P<0.0001), nuclear grade (P=0.003), with ER negativity (P=0.003) and with HER-2 positivity (P<0.0001). Cyclooxygenase type-2 expression is upregulated in in situ breast cancer and is associated with surrogate markers of an aggressive DCIS phenotype including nonoestrogen-regulated signalling pathways. Cyclooxygenase type-2 inhibition may potentially prevent the development of ER-positive and ER-negative breast cancers.

Adult↗
PubMed2003

Biological response to hormonal manipulation in oestrogen receptor positive ductal carcinoma in situ of the breast.

Adjuvant antioestrogen therapy with tamoxifen is recommended for all women following breast-conserving surgery for ductal carcinoma in situ (DCIS) to reduce local recurrence, despite 50% of lesions being oestrogen receptor (OR) negative. We have investigated the response to hormone manipulation in DCIS by studying changes in epithelial proliferation and progesterone receptor (PR) expression as surrogate molecular markers of treatment effects in DCIS of known OR status. Women were identified who had undergone diagnostic core biopsy followed by surgery for DCIS 14-41 days later. Ki67 (a measure of epithelial cell proliferation) and PR expression were determined by immunohistochemistry on paired paraffin sections of the core biopsy and operative specimens for each patient, with OR and HER-2 measured on the operative specimen. Women were divided into three groups according to whether they had changed hormone therapy (stopped hormone replacement therapy (HRT), group 1), continued taking HRT (group 2) or were not taking HRT (group 3) between core biopsy and surgery. In OR-positive (but not in OR-negative) DCIS after oestrogen withdrawal (group 1), a fall in the mean cell proliferation (P&<0.01) was observed. A fall in PR expression between core biopsy and surgery was also seen in this group (P=0.02). No change in either mean cell proliferation or PR expression was seen in the other two groups in OR-positive or -negative DCIS. The fall in proliferation and PR expression occurred regardless of HER-2 status. In conclusion, a biological response to hormone manipulation is only seen in OR-positive DCIS tumours. Any clinical value of antioestrogen therapy is likely to be restricted to this group.

Adult↗
PubMed2003

Diagnostic evaluation of pulmonary tuberculosis: what do doctors of modern medicine do in India?

SETTING: Out- and in-patient services of the Department of Tuberculosis and Chest Diseases, King George's Medical College, Lucknow, India. OBJECTIVE: To analyse diagnostic practices for pulmonary tuberculosis (PTB) among doctors of modern medicine and to estimate their association with diagnostic accuracy. DESIGN: A consecutive case series. The diagnostic practices of 518 doctors who had prescribed treatment for PTB to 270 patients were analysed. RESULTS: Almost all of the doctors (99.8%, 95% CI 98.9-100.0) used chest X-ray, while 49.2% (95% CI 44.8-53.6) advised chest X-ray alone for diagnosis of PTB. On the other hand, 50.6% (95% CI 46.2-55.0) performed sputum microscopy while none used it without chest X-ray. Sputum microscopy was used three times more frequently by chest specialists compared with non-chest specialists (81.9% vs. 25.8%, P = 0.0000). Non-utilisation of sputum microscopy was associated with a significantly higher probability of prescribing anti-tuberculosis treatment for PTB in patients with non-tuberculous conditions (odds ratio 5.0; 95% CI 2.72-9.83). CONCLUSION: Non-utilisation of sputum smear microscopy and continued reliance on chest X-ray only by up to 49% of practitioners of modern medicine might have serious public health implications. Strategies for their continued medical education and audit of their practices should be implemented without delay.

Humans↗