Biomedical subjects

P Srinivas

Publications and source records attributed to P Srinivas.

At least 19 recordsLinked to original sources

PubMed2006

Sorption of copper(II) ion from aqueous solution by Tectona grandis l.f. (teak leaves powder).

Studies on a batch sorption system using Tectona grandis l.f. as adsorbent was investigated to remove copper(II) from aqueous solutions. The adsorption experiments were performed under various conditions such as different initial concentrations, pH, adsorbent dosage and adsorbent particle size. The data showed that 0.1 g of Tectona grandis l.f. was found to remove 71.66% of 20 mg/L copper(II) from 30 mL aqueous solution in 180 min. The experimental equilibrium data were adjusted by the adsorption isotherms from Langmuir and Freundlich models and their equilibrium parameters were determined. The best-adjusted model to the experimental equilibrium data for Tectona grandis l.f. was the Langmuir model. Using the Langmuir model equation, the monolayer sorption capacity of Tectona grandis l.f. was evaluated and found to be 95.40 mg/g. The optimum pH value was found to be 5.5. The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data. The dynamic data fitted the pseudo-second-order kinetic model.

Adsorption↗

PubMed2006

Compensator-based intensity-modulated radiotherapy in head and neck cancer: our experience in achieving dosimetric parameters and their clinical correlation.

AIMS: To review the Batra Hospital and Medical Research Centre experience of using compensator-based intensity-modulated radiotherapy (IMRT) to treat head and neck cancer. MATERIALS AND METHODS: Between October 2003 and August 2004, 18 patients underwent IMRT for head and neck cancer at our institution. IMRT was delivered using partial transmission high-resolution compensator blocks. RESULTS: With a median follow-up of 13.3 months, two patients had residual disease and two failed in the gross tumour volume (GTV). The complete response rate after surgical salvage was 94.5%. Both the locoregional relapse-free and disease-free survival rates were 81.8%. The target coverage in terms of average maximum, mean and minimum dose (in Gy) delivered was 78.6, 73.5 and 58.4 to the GTV-planning target volume, 82.3, 70.9 and 47.3 to clinical target volume 1 (CTV1) and 82.9, 66.2 and 29.6 to CTV2. The dose constraint of 30 Gy to less than 50% of the contralateral parotid volume was achieved in 12 (66.7%) patients. If the dose constraint was revised to 35 Gy, at least 50% of the parotid volume was spared in 17 (94.5%) patients. On average, 75% of the contralateral parotid volume received a dose less than 35 Gy in 13 (72.3%) patients with grade I xerostomia, whereas this was 49.3% in five (27.7%) patients with grade II xerostomia, and the difference was statistically significant (P = 0.001). CONCLUSIONS: In our initial experience, compensator-based IMRT is feasible with regard to target coverage and parotid volume sparing. The parotid volume dose has significant clinical implications on the grade of xerostomia. Our results invoke rethinking into the issues of the parotid volume dose constraint in our subpopulation.

Carcinoma, Squamous Cell↗

PubMed2005

Immune cascade of Spodoptera litura: cloning, expression, and characterization of inducible prophenol oxidase.

Haemolymph associated phenol oxidase is a critical component of invertebrate immune reaction and cuticle sclerotization. Phenol oxidase catalyses the conversion of mono-phenols to diphenols and quinones which finally leads to melanin formation. We have cloned the c-DNA encoding phenol oxidase from the haemocytes of Spodoptera litura and expressed it in Escherichia coli. The encoding gene is 2452bp with an open reading frame of 2091 bp translating into a 697 amino acid protein. Multiple alignment analysis of the predicted protein sequence shows close homology to other lepidopeteran PPOII type genes. The transcription of the gene is induced upon microbial challenge of 6th instar larvae with E. coli and is unresponsive to injury. Cloning of the ORF of SLPPO in-frame in the E. coli expression vector pQE30 resulted in its expression. Enzymatic analysis of the recombinant protein reveals that the recombinant protein is catalytically active on 4-methyl pyrocatechol upon activation by cetyl pyridinium chloride.

Amino Acid Sequence↗

PubMed2003

Direct conversion of tert-beta-bromo alcohols to ketones with zinc sulfide and DMSO.

tert-Beta-bromo alcohols, derived from simple monoterpene hydrocarbons, react with zinc sulfide in dimethyl sulfoxide to afford saturated ketones as the major and hydroxy ketones as the minor products. The reaction involves initial nucleophilic attack by DMSO on the carbon attached to the halogen, which is assisted by electrophilic zinc sulfide. Subsequent Kornblum type oxidation yields the alpha-hydroxy ketone. On the other hand, abstraction of proton beta to the hydroxyl group followed by an attack of the neighboring hydroxyl moiety on the sulfur of the dimethylsulfoxonium intermediate and its subsequent collapse yields an enol, which tautomerizes to a saturated ketone. The latter pathway is predominantly followed.

Journal Article↗

PubMed2002

Apoptotic index: use in predicting recurrence in breast cancer patients.

Apoptosis maintains tissue homeostasis through its ability to control cell population and has been extensively studied in human cancers. Relation of apoptosis to prognosis is still controversial. In this study, we analyzed the prognostic significance of apoptotic and mitotic indices (AI & MI) using hematoxylin and eosin stained slides by light microscopy in breast cancer patients. In our study, apoptotic index was significantly associated with predicting relapse free survival (RFS), distant recurrence free survival (DRFS) and overall survival (OS) with lesions having higher apoptotic index showing poor prognosis. Our results also point out that quantitation of apoptotic index by simple light microscopy as a routine practice along with histological diagnosis, could provide additional prognostic information in patients who are at high risk of developing recurrence with breast cancers.

Adenocarcinoma, Mucinous↗

PubMed2002

Nm23H1 and p53 proteins are differentially correlated to metastasis in breast carcinoma.

The prognostic significance of nm23H1 and p53 proteins as predictors of nodal involvement and distant recurrence was evaluated in 63 cancer and 47 benign lesions of the breast. Assessment was carried out by immunohistochemical staining using nm23H1 and p53 antibodies. Results show no relation of nm23H1 either to the malignant nature when compared to benign lesions or to the nodal status. P53 protein, on the other hand, showed significantly increased expression in malignant lesions (p=0.001) and correlated well with nodal positivity (p=0.03). A follow-up study of 5 years showed that among the cases showing recurrence, those with positive mn23H1 showed a shorter distant recurrence free survival (DRFS, p=0.01), while p53 expression had no effect. This result did not agree with the previous reports showing nm23H1 as an antimetastatic gene. This is the first report of positive correlation between nm231-11 and distant recurrence in breast cancers, though such a correlation was reported earlier in certain other cancers. Since nm23H1 is an NDP kinase, having more involvement in signal transduction of cell proliferation, it is not difficult to comprehend such a role for nm23H1 during recurrence. Combining the expression of both proteins, lesions positive for both p53 and nm23H1 had significantly reduced distant recurrence free survival (DRFS), when compared to those negative for both proteins (p=0.0006). It can be concluded that nni23H1 alteration has a potential in predicting DRFS, while p53 alteration has the potential to predict lymph node involvement.

Breast Neoplasms↗

PubMed2001

Cross-resistance and resistance longevity as induced by bean leaf beetle, Cerotoma trifurcata and soybean looper, Pseudoplusia includens herbivory on soybean.

Cross-resistance, and longevity of resistance, induced by the bean leaf beetle, Cerotoma trifurcata, was studied IN the soybean PI 227687 that exhibited induced response in earlier studies. Bean leaf beetle adults and soybean looper, Pseudoplusia includens, larvae were used to induce resistance and to determine beetle feeding preference. Beetles were collected from soybean fields 2 to 5 days prior to the feeding preference test. The level of cross-resistance induced by soybean looper herbivory to subsequent bean leaf beetle feeding was higher when compared to cross-resistance induced by bean leaf beetle herbivory against subsequent feeding by soybean looper. Further, herbivory by the bean leaf beetle also induced resistance against soybean looper feeding. In the longevity study, leaflets from treated plants were collected 5, 10, 12, 14, 16, 20 and 25 days after initiation of feeding. Pairwise comparisons of leaflets from plants treated by bean leaf beetle herbivory with untreated plants revealed that induced responses were highest 14 and lowest 25 days after initiation of feeding. On other sampling days, levels of induced response varied with the sampling day.

Animals↗

PubMed2001

Cadherins as predictive markers of nodal metastasis in breast cancer.

Adhesion molecules, particularly cadherins play a pivotal role in cancer invasion and metastasis. Because the therapeutic management of tumors with and without nodal metastasis differs considerably, our idea was to identify tumors with metastatic potential. We studied the expression of E-cadherin and P-cadherin immunohistochemically in 51 cases of breast cancer that included 29 node-negative and 22 node-positive cases. Expression of the cadherins was mainly membranous, with cytoplasmic staining in a few lesions. Both E-cadherin and P-cadherin showed significant down-regulation of their expression in node-positive tumors in comparison to node-negative tumors. Logistic regression analysis revealed that the positive expression of E-cadherin and P-cadherin showed low odds ratios of 0.1 and 0.2, respectively, and were statistically significant. On multivariate analysis, both the cadherins were found to be of independent prognostic value. This suggests that cadherin expression could be a marker of nodal metastasis. An observation of interest was that the expression of E-cadherin and P-cadherin were highly correlated (correlation coefficient = 0.5873), which requires further evaluation for confirmation of a common regulatory pathway that could be activated in the early onset of nodal metastasis.

Adenocarcinoma↗

PubMed2001

Synthesis of new arylaminoquinoxalines and their antimalarial activity in mice.

2-Arylaminoquinoxalines were prepared by the condensation of 2-chloroquinoxaline with the appropriate Mannich bases in the presence of HCl. To synthesize the Mannich bases, 4-acetamidophenol was reacted with formaldehyde and dialkylamine to yield 3-[(dialkylamino) methyl]-4-hydroxyacetanilide, followed by hydrolysis. Antimalarial activities of the new arylaminoquinoxalines were evaluated against the rodent malaria parasite Plasmodium yoelii at a dose of 75 mg kg(-1). Three compounds synthesized (2-[3-[(diethylamino) methyl]-4-hydroxyanilino]-quinoxaline dihydrochloride (2b), 2-[3-[(pyrrolidinyl) methyl]-4-hydroxyanilino]-quinoxaline dihydrochloride (2f), and 2-[3-[(piperidinyl) methyl]-4-hydroxyanilino]-quinoxaline dihydrochloride (2g)) showed moderate antimalarial activity.

Animals↗

PubMed2000

Genetic and transcriptional analysis of a regulatory region in streptococcal conjugative transposon Tn5252.

In an attempt to increase our understanding of the mechanisms of conjugal transposition among gram-positive bacteria, we analyzed the genetic and structural properties of a 1.2-kb DNA fragment at the left end of the streptococcal conjugative transposon Tn5252. The sequence data revealed four short open reading frames. Polypeptides likely to correspond to two of these genes were identified. Transcriptional start sites and the promoter sequences of three transfer-related genes in the left terminal region of the element were identified. The deduced amino acid sequence of one of these, ORF3, was found to be similar to that of several prokaryotic transcriptional regulator proteins. Insertion mutagenesis at this locus reduced the transfer of the element by three orders of magnitude. The presence of a multicopy plasmid carrying ORF3 in a donor cell carrying Tn5252 with a mutated copy of ORF3 or an unaltered element also reduced the transfer frequency of the element similarly. Gel mobility shift assays showed that the ORF3 protein was capable of binding to not only other discrete sites at the left end of the element but also its own promoter, suggesting autoregulation. These results indicate that the ORF3 protein is involved in the regulation of the conjugative transposition of the element.

Amino Acid Sequence↗

PubMed2000

Localised nodular pulmonary amyloidosis in a patient with sicca syndrome.

A 52 year old Chinese woman with a 25 year history of sicca syndrome (primary Sjogrens syndrome) was investigated for 3 episodes of haemoptysis. Clinical examination was unremarkable except for the presence of dry eyes and xerostomia. Computed tomography of the chest revealed a lobulated mass in the posterior basal segment of the left lower lobe. Histopathological examination of this resected nodule confirmed the diagnosis of nodular amyloidosis. The normal radiolabelled serum amyloid P component scintigraphy and the absence of monoclonal plasma cell dyscrasia in the bone marrow strongly support the diagnosis of localised nodular pulmonary AL amyloidosis in this patient. Nodular pulmonary amyloidosis can be associated with sicca syndrome and often simulates bronchogenic carcinoma, bronchiectasis or pulmonary tuberculosis.

Amyloidosis↗

PubMed1999

Synthesis and preliminary pharmacological investigations of 1-(1,2-dihydro-2-acenaphthylenyl)piperazine derivatives as potential atypical antipsychotic agents in mice.

In research towards the development of new atypical antipsychotic agents, one strategy is that the dopaminergic system can be modulated through manipulation of the serotonergic system. The synthesis and preliminary pharmacological evaluation of a series of potential atypical antipsychotic agents based on the structure of 1-(1,2-dihydro-2-acenaphthylenyl)piperazine (7) is described. Compound 7e, 5-{2-[4-(1,2-dihydro-2-acenaphthylenyl)piperazinyl]ethyl}-2,3-dihy dro-1H- indol-2-one, from this series showed significant affinities at the 5-HT1A and 5-HT2A receptors and moderate affinity at the D2 receptor. 7e exhibits a high reversal of catalepsy induced by haloperidol indicating its atypical antipsychotic nature.

Animals↗

PubMed1999

Cervical osteoarthropathy: an unusual cause of dysphagia.

PRESENTATION: A 72-year-old man complained of progressive dysphagia for solids associated with a sensation of foreign body in his throat for 2 years. A barium swallow showed a bridging osteophyte between C4 and C5 vertebrae indenting the oesophagus posteriorly and displacing it anteriorly. OUTCOME: He refused surgical intervention and was given dietary advice. After 6 months, his weight was steady and he was able to swallow semi-solid food without difficulty.

Aged↗

PubMed1999

Peak expiratory flow rate in elderly Malaysians.

An epidemiological survey was conducted among 1,414 healthy ambulatory elderly persons aged 55 years and above in the Kuala Langat district, Selangor. The relationship between peak expiratory flow rate (PEFR), demographic variables, socioeconomic status, smoking, alcohol use and respiratory symptoms were examined. The peak expiratory flow declined with age and were lower in women of all ages. Smoking had a modest effect on PEFR in men but not on PEFR in women. The combination of respiratory symptoms of cough, phlegm and wheeze were related to lower PEFR values. Prediction equations are presented derived from the population sample which may be of assistance in assessing observed to expected ratios among elderly people in Malaysia.

Aged↗

PubMed1999

Diagnosis and management of Alzheimer's disease--an update.

Alzheimer's disease (AD) has become recognised as a major cause of morbidity and mortality in the ageing population worldwide. Over 20 million people worldwide are affected by AD, which ensures that the disease imposes a major economic burden. Alzheimer's disease is a progressive neurodegenerative disorder with characteristic clinical and neuropathological features. Neurofibrillary tangles, neuritic plaques and amyloid angiopathy occur in varying severity in brains of patient's with Alzheimer's disease. Biological markers of AD allowing an early definitive premorbid diagnoses are currently not available. Memory loss for recent events is invariable and often the earliest prominent symptom. Language disorders, difficulties with complex tasks, depression, psychotic symptoms and behavioral changes are other common manifestations of AD. Diagnosis involves the early detection of cognitive decline and ruling out other causes of dementia like vascular dementia, Lewy body dementia, fronto-temporal degeneration or reversible causes like hypothyroidism. Acetylcholinesterase inhibitors have shown to be effective in mild to moderate AD in improving the cognitive function of patients in clinical trials. Caregiver intervention programs have considerable potential to improve both the caregiver and patient quality of life.

Alzheimer Disease↗

PubMed1998

Detection of Mycobacterium tuberculosis in bronchoalveolar lavage from patients with sputum smear-negative pulmonary tuberculosis using a polymerase chain reaction assay.

The objective of this study was to evaluate the utility of a polymerase chain reaction (PCR) assay in detecting Mycobacterium tuberculosis in bronchoalveolar lavage (BAL) specimens of patients suspected of having active pulmonary tuberculosis (TB) but who were sputum smear-negative. Patients undergoing investigation for suspected pulmonary TB at the University Hospital, Kuala Lumpur, and who were sputum smear-negative underwent fibreoptic bronchoscopy and BAL. One portion of each lavage specimen was submitted for smear examination for acid-fast bacilli and mycobacterial culture and the other portion assayed by PCR for the presence of a 562-base pair DNA segment belonging to the insertion sequence IS986, unique to the M. tuberculosis complex. As controls, lavage specimens from patients with other lung lesions were also similarly tested. The PCR assay gave a positivity rate of 80.9% (55 of 68) compared with 8.8% of smear examination and 7.4% of culture for detecting M. tuberculosis in BAL specimens. The assay was positive in two of 45 BAL specimens from 35 control subjects. The PCR assay was more sensitive than smear and culture in detecting M. tuberculosis in BAL specimens of patients with sputum smear-negative pulmonary TB.

Acute Disease↗

PubMed1998

Common fears of patients undergoing bronchoscopy.

In the world of medical literature, little has been reported about the fears of patients undergoing bronchoscopy. The aim of this study was to identify the common fears of patients undergoing fibreoptic bronchoscopy and to determine whether any factors might contribute to reducing these fears. One hundred and four consecutive patients undergoing bronchoscopy were interviewed. Sixty one patients expressed fear about the procedure, as follows: afraid of pain (33); afraid of breathing difficulties (11); afraid of oropharyngeal irritation (5); afraid of the bronchoscopy findings (2); afraid of sedation, cross-infection and nasal lignocaine spray, respectively (3); and unable to be specific (7). There was no difference between the "no fear" and "fearful" groups in ethnicity, source of referral, education, previous endoscopy, doctors' explanation and the patients' understanding of the procedure and its indication. "Fearful" patients were significantly younger (t=2.082, p=0.037) and female (chi2=4.180, p=0.038). Doctors were more likely to explain the indication for bronchoscopy than how it would be performed (chi2=6.403; p=0.011), and patients were more likely to understand why they needed a bronchoscopy than how it would be performed (chi2=21.505; p<0.001). Fear preceding bronchoscopy is independent of patients' demographic features except for age and gender. Doctors tend to explain "why" but not "how" the procedure is performed. Provision of detailed information about sensations that are likely to be experienced in bronchoscopy could be used to allay some of these common fears.

Attitude to Health↗

PubMed1998

A profile of hypertension among rural elderly Malaysians.

The main objective of this study was to survey the prevalence of hypertension in Malaysians aged 55 years and above who responded to a public health screening campaign in Kuala Langat district, Selangor, Malaysia. The relationship between the detection, treatment and control in the study population was also examined. An epidemiological survey of the elderly was conducted in Kuala Langat, a rural district in Malaysia for a consecutive period of six weeks. The survey was conducted using a standardized questionnaire and interview by trained research assistants. The medical students and nurses were trained on the correct protocol of measuring blood pressure based on the recommendations of the British Hypertension Society. Newly detected persons with blood pressure readings 160/95 mmHg and above, were given a green card to return to the nearest health center for a further 2 visits to check his/her blood pressure. A total of 1,392 people with a mean age of 65 years and comprising of 53.1% males and 46.9% females responded to the health survey. Based on the history 335 (24.1%) of the respondents were known hypertensives and 82.1% of this hypertensive group were on regular treatment. However good control of hypertension was achieved only in 161 (48.1%) of them. Newly detected hypertension was found in 204 (14.6%) of the respondents. The overall prevalence of hypertension in our sample of respondents was 25.6%. There was no significant difference between the sexes and the races in terms of their detection, treatment and control. However there was a significant difference between the persons aged less than 65 years of age and those older than 65 years. There was a large proportion of previously known hypertensives among the survey population. Of those detected, not all were on regular medications and the majority on medications were not well controlled. Education of the public through intensive public health campaigns is vital to improve their knowledge on hypertension and the need for effective control. More community studies are needed to formulate better methods in the detection, treatment and control of hypertension.

Age Distribution↗