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Biomedical subjects

Seema

Publications and source records attributed to Seema.

10 recordsLinked to original sources
PubMed2007

Ellagic acid peracetate is superior to ellagic acid in the prevention of genotoxicity due to aflatoxin B1 in bone marrow and lung cells.

Earlier observations carried out in our laboratory highlighted the mode of action of acetoxy 4-methylcoumarins and quercetin pentaacetate in preventing the genotoxicity of aflatoxin B1 (AFB1). We have extended the observation to an acetoxy biscoumarin i.e. ellagic acid peracetate (EAPA), which unlike ellagic acid (EA) has demonstrated time-dependent inhibition of liver microsomes catalysed AFB1-epoxidation as measured by AFB1 binding to DNA. EAPA was more potent than EA in preventing bone marrow and lung cells from AFB1-induced genotoxicity. EAPA was acted upon by microsomal acetoxy drug:protein transacetylase (TAase) leading to modulation of the catalytic activity of certain functional proteins (cytochrome P450, NADPH cytochrome c reductase and glutathione S-transferase), possibly by way of protein acetylation.

Acetyltransferases↗
PubMed2005

Acetoxy drug: protein transacetylase catalyzed activation of human platelet nitric oxide synthase by polyphenolic peracetates.

An enhanced intracellular level of Nitric oxide (NO) is essential to ameliorate several pathological conditions of heart and vasculature necessitating the activation of NOS. We have projected in this report the acetylation of eNOS by polyphenolic peracetates (PA) catalyzed by the novel enzyme acetoxy drug: protein transacetylase (TAase) discovered in our laboratory as an unambiguous way of activating NOS which results in the manifestation of physiological action. The human platelet was chosen as the experimental system in order to validate the aforementioned proposition. PA caused profound irreversible activation of platelet NADPH cytochrome c reductase mediated by TAase. The convincing biochemical evidences are presented to show that PA could cause acetylation of the reductase domain of NOS leading to the activation of eNOS in tune with their specificities to platelet TAase. As a result, the enhanced level of NO due to activation of platelet eNOS by PA was found to inhibit the ADP-induced platelet aggregation. The present studies highlight for the first time the role of PA as the novel potent agent for enhancing the intracellular NO levels.

Acetates↗
PubMed2005

Bacteriological study of paediatric and adult chronic suppurative otitis media.

Chronic suppurative otitis media (CSOM) is one of the commonest illnesses in ENT practice which requires medical attention all the more in children of poor socio-economic status having in past inadequate treatment and negligent medical care. The present study was conducted to find out the various aerobic and anaerobic microorganisms associated with CSOM in paediatric and adult cases and their current antimicrobial susceptibility pattern as a guide to therapy. Samples were collected from 109 clinically diagnosed cases of CSOM and processed according to standard protocols. Out of 74 paediatric CSOM cases, 72 (97.2%) were bacterial culture positive while out of 35 adult CSOM cases, 28 (80%) were culture positive. Bilateral CSOM was slightly more common in adults (25%) than paediatric (21.4%) age group. Polymicrobial nature of CSOM was noted in both paediatric (70.8%) and adult (71.4%) cases while number of organisms isolated per lesion was slightly higher in adults (2.5) as compared to paediatric (1.95) cases. In paediatric CSOM, Staphylococcus aureus was the commonest aerobic isolate while in adult CSOM, Pseudomonas aeruginosa was the commonest one. Among anaerobes Peptostreptococcus spp. was commonest in CSOM where as Prevotella melaninogenica in adult CSOM. Sensitivity of S. aureus to cefuroxime was 72.2% while that of gram negative bacilli was higher to cefotaxime (90 to 100%). Among anaerobes higher sensitivity was seen to metronidazole (98.6%), clindamycin (95.7%) and chloramphenicol (98.6%). In view of the polymicrobial etiology of CSOM, prompt appropriate antimicrobial therapy can effectively reverse the disease process thereby preventing longterm sequelae.

Adult↗
PubMed2004

Acetoxy drug: protein transacetylase of buffalo liver-characterization and mass spectrometry of the acetylated protein product.

The purification and characterization of the buffalo liver microsomal transacetylase (TAase) catalyzing the transfer of acetyl groups from a model acetoxy drug: 7,8-diacetoxy-4-methylcoumarin (DAMC) to GST3-3 has been described here. The enzyme was routinely assayed using DAMC and cytosolic GST as the substrates and was partially purified from microsomes of the buffalo liver. The enzyme was found to have approximate molecular of weight 65 kDa. The action of TAase and DAMC on liver cytosolic GST resulted in the formation of monoacetoxymonohydroxy-4-methylcoumarin (MAMHC) and 7,8-dihydroxy-4-methylcoumarin (DHMC), although the former was the major metabolite. The buffalo liver microsomal TAase exhibited hyperbolic kinetics and yielded K(m) (1667 microM) and V(max) (192 units) when the concentration of DAMC was varied keeping the concentration of GST constant. After having characterized the nature of the substrates and a product of the TAase-catalyzed reaction, we set out to identify the acetylated protein which is another product of the reaction. GST3-3 was used as a model protein substrate for the action of TAase using DAMC as the acetyl donor. The subunit of control and modified GST3-3 were separated by SDS-polyacrylamide gel electrophoresis (PAGE) and digested with trypsin. The tryptic peptides were extracted from the gel pieces and analyzed by matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOFMS). The data search for calibrated and labeled mass peaks of peptides was performed on the Matrix Science Server using the search engine Mascot. The peptide maps so obtained covered 97% of the GST3-3 sequence. On comparison of MALDI peptide maps of modified and control GST, seven new peaks were recognized corresponding to the potentially acetylated peptides in peptide map. The mass value of each of them was 42 Da higher than the theoretical mass of a non-modified GST3-3 tryptic peptide, strongly suggesting acetylation. By examining the fragmentation patterns and by comparing experimental and predicted values for MS/MS daughter ions, the identity of the seven acetylated GST tryptic peptides could be confirmed by the application of LC/MS/MS. In the modified GST, N-terminal proline and six lysines (Lys(51), Lys(82), Lys(123), Lsy(181), Lys(191) and Lys(210)) were found to be acetylated. The structure of acetylated GST revealed that the lysines that underwent acetylation were peripheral in positions.

Acetylation↗
PubMed2000

Spontaneous rupture of choledochal cyst.

Choledochal cyst in an uncommon congenital anomaly with classic presentation triad of abdominal pain, jaundice and right upper abdominal mass. Presentation due to biliary peritonitis following cyst rupture is extremely rare. One such case which was successfully treated is being reported.

Choledochal Cyst↗
PubMed1997

Relactation: an effective intervention to promote exclusive breastfeeding.

Fifty mothers of hospitalized infants less than 4 months old with partial or complete lactation failure (LF) were randomly assigned to two groups of 25 each for relactation. Majority of enrolled mothers (86 per cent) had complete LF and 14 per cent had partial LF. Relactation was attempted in both the groups with motivation, support, and repeated suckling. Group II mothers, in addition, were given metoclopramide. The characteristics of mothers and babies, and socio-economic background were comparable in both groups (P > 0.05). The primary outcome variables measured included the time of appearance of first breast milk secretion (in complete LF), time for partial and complete relactation. Relactation attempt was successful in 49 mothers (98 per cent), with complete relactation in 46 (92 per cent) and only partial relactation in three mothers (6 per cent). Nipple confusion and frustration of the baby (4 per cent) in complete LF, small/retracted nipples (8 per cent), and sore/fissured nipples (4 per cent), which influenced the initiation of relactation, were overcome with drop and drip method, lact-aid support and proper positioning of the baby. All the outcome variables of the two groups were comparable (P > 0.05). The pattern of weight gain, the rate of reduction in the amount of top milk and subsequent weight gain in the follow-up was also comparable in both the groups (P > 0.05). Maternal factors like breast conditions, nutrition, parity, feeding practices in previous babies, lactation gap, and infants' initial refusal to suck at the breast did not influence the outcome variables as long as repeated suckling was ensured. We conclude that relactation is possible in most of the mothers without the help of lactagogues. Apart from educating and motivating the mother for exclusive breastfeeding during first 4-6 months, a strong professional support by a skilled health worker is needed to overcome the initial problems during relactation.

Adult↗
PubMedDate not supplied

Serum TNF-alpha and free radical scavengers in neonatal septicemia.

Tumor necrosis factor-alpha (TNF-alpha) and free radicals have been implicated in the pathogenesis of neonatal septicemia and its complications. This case control study was conducted between November 1996 to July 1997 to determine the levels of TNF-alpha and free radical scavengers viz. superoxide dismutase (SOD) and glutathione peroxidase (GPX) in the serum of 30 septic neonates and 20 healthy controls. Patients with neonatal sepsis registered significantly higher levels of TNF-alpha, SOD and GPX in comparison to controls (p < 0.05). The neonates with septic shock had five fold increase in TNF-alpha levels (2262 +/- 605.8 pg/ml) as compared to those without shock (738.8 +/- 728.8 pg/ml). There was no statistically significant difference in levels of antioxidant enzymes between neonates with shock and without shock. The levels of TNF-alpha and antioxidant enzymes were not affected by the type of organism isolated in blood culture.

Case-Control Studies↗