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Biomedical subjects

S Pal

Publications and source records attributed to S Pal.

At least 19 recordsLinked to original sources
PubMed2006

Role of toxin and nutrient for the occurrence and termination of plankton bloom--results drawn from field observations and a mathematical model.

The termination of harmful algal blooms (HABs) and coexistence of phytoplankton-zooplankton populations are of great importance to human health, ecosystem, environment, tourism and fisheries. In this paper we propose a three-component model consisting of dissolved limiting nutrients (N) supplied at constant rate and partially recycled after the death of plankton by bacterial decomposition, phytoplankton (P) and zooplankton (Z), where the growth of zooplankton species reduce due to toxic chemicals released by phytoplankton species. Our analysis leads to different thresholds which are expressible in terms of model parameters and determine the existence and stability of various states of the system. We observe that phytoplankton-zooplankton persist if the maximal zooplankton ingestion rate exceeds a lower threshold value. It is shown that the coexistence equilibrium loses its stability when the dilution rate of the nutrient concentration passes through a critical value and Hopf bifurcation occurs that induces oscillations of the population. Our results indicate that the occurrence of bloom increases when the nutrient concentration is very high, and in that case toxin produced by the phytoplankton plays a very crucial role towards the termination of the planktonic bloom.

Algorithms↗
PubMed2006

The range and nature of sleep dysfunction in untreated Parkinson's disease (PD). A comparative controlled clinical study using the Parkinson's disease sleep scale and selective polysomnography.

In this study we have explored the nature and range of sleep dysfunction that occurs in untreated Parkinson's disease (PD) comparing data obtained from the use of the Parkinson's disease sleep scale (PDSS) in an untreated PD patient group compared to advanced PD and healthy controls. 25 untreated (drug-naive, DNPD) PD patients (mean age 66.9 years, range 53-80, 18 males) completed the validated Parkinson's disease sleep scale (PDSS), mean duration of PD was 2.1 years (1-10, up to 4 years in all except one patient with tremulous PD reporting tremor duration of 10 years) and mean Hoehn and Yahr score 1.9 (1-3). Data were compared to 34 advanced PD (mean age 70.2 years, range 51-88, 23 male), mean duration of PD 11 years (range 4-22), mean Hoehn and Yahr score 3.4 (3-5) and PDSS data obtained from 131 healthy controls (mean age 66.6 years, range 50-93, 56 males). Total PDSS scores and PDSS sub-items, except PDSS item 2, were highly significantly different (p<0.001) between DNPD, advanced PD and controls. Controls reported higher mean PDSS scores than both groups of patients, and advanced cases reported lower (mean+/-S.D.) PDSS scores (86.95+/-20.78) than drug-naive (105.72+/-21.5) (p<0.001). Logistic regression analysis showed that items PDSS8 (nocturia), PDSS11 (cramps), PDSS12 (dystonia), PDSS13 (tremor), and PDSS15 (daytime somnolence) were significantly impaired in DNPD compared to controls while PDSS7 (nighttime hallucinations) additionally separated advanced PD from DNPD. In a subgroup of 11 advanced PD cases (mean age 62 years, range=49-84 years, mean Hoehn and Yahr score 2.5, range=1-3) with high Epworth Sleepiness Scale (ESS) scores (mean 14.5), low item 15 PDSS score (mean 4.7) and complaints of severe daytime sleepiness, underwent detailed overnight polysomnography (PSG) studies, all showing abnormal sleep patterns. We conclude that nocturia, nighttime cramps, dystonia, tremor and daytime somnolence seem to be the important nocturnal disabilities in DNPD and some of these symptoms may be reminiscent of "off" period related symptoms even though patients are untreated. Furthermore, polysomnography in "sleepy" PD patients may help diagnose unrecognised conditions such as periodic limb movement of sleep (PLMS), obstructive sleep apnoea (OSA) and REM Sleep Behaviour Disorder.

Aged↗
PubMed2006

MRI-guided needle localization of suspicious breast lesions: results of a freehand technique.

Magnetic resonance imaging (MRI) can detect clinically and mammographically occult breast lesions. In this study we report the results of MRI-guided needle localization of suspicious breast lesions by using a freehand technique. Preoperative MRI-guided single-needle localization was performed in 220 patients with 304 MRI-only breast lesions at our hospital between January 1997 and July 2004. Procedures were performed in an open 0.5-T Signa-SP imager allowing real-time monitoring, with patient in prone position, by using a dedicated breast coil. MRI-compatible hookwires were placed in a noncompressed breast by using a freehand technique. MRI findings were correlated with pathology and follow-up. MRI-guided needle localization was performed for a single lesion in 150 patients, for two lesions in 56 patients, and for three lesions in 14 patients. Histopathologic analysis of these 304 lesions showed 104 (34%) malignant lesions, 51 (17%) high-risk lesions, and 149 (49%) benign lesions. The overall lesion size ranged from 2.0-65.0 mm (mean 11.2 mm). No direct complications occurred. Follow-up MRI in 54 patients showed that two (3.7%) lesions were missed by surgical biopsy. MRI-guided freehand needle localization is accurate and allows localization of lesions anterior in the breast, the axillary region, and near the chest wall.

Adult↗
PubMed2006

The effect of chronic consumption of red wine polyphenols on vascular function in postmenopausal women.

OBJECTIVE: To elucidate whether the chronic consumption of dealcoholised red wine (DRW) (polyphenol-rich component) and/or red wine (RW) improves vascular function in hypercholesterolaemic postmenopausal women. DESIGN, SUBJECTS AND INTERVENTION: A randomised parallel-arm study. Forty-five hypercholesterolaemic postmenopausal women were randomised into either water, DRW or RW group for 6 weeks following a 4 week washout. Fasting measures of central haemodynamic parameters, arterial wave reflection and endothelial nitric oxide were taken at 0 and 6 weeks. SETTING: Clinic in the School of Public Health, Curtin University. RESULTS: There were no significant between group differences in arterial stiffness as measured by augmentation index (AIx) and augmentation pressure (AP). However, a significant within group decrease in AIx (-9%, P=0.02) and AP (-12%, P=0.02) was observed following DRW consumption. No significant changes were observed in central haemodynamic parameters and endothelial nitric oxide levels following DRW and RW consumption, compared to water. CONCLUSIONS: Neither the chronic consumption of DRW nor RW improved markers of arterial stiffness, compared to control. However, the significant within group improvements in these indices following the consumption of DRW cannot be overlooked and warrant further investigation.

Aged↗
PubMed2006

Caspase-3 induced apoptosis in transgenic zebrafish.

Zebrafish is an attractive model organism for studying apoptosis development because of its genetic accessibility. Here we describe the induction of clonally derived apoptosis in transgenic zebrafish expressing mouse caspase-3 (CASP3) under control of the zebrafish beta-actin promoter (betap). Visualization of apoptotic cells, expressing a chimeric transgene encoding CASP3 fused to green fluorescent protein (GFP) gene, revealed that apoptosis arose in the thymus, spread locally into gill arches and retro-orbital soft tissue, and then disseminated into abdominal organs like testis, kidney. This transgenic model provides a platform for over-expression of caspase-3 induced extensive apoptosis in embryos and adult.

Actins↗
PubMed2006

Sleep-related problems of Parkinson's disease.

OBJECTIVE: To define the epidemiology, characteristics and aetiology of nocturnal symptoms and sleep disorders in patients with Parkinson's disease (PD) and evaluate the available methods for their diagnosis and management. METHODS: A review of the English-language literature pertaining to sleep disturbances associated with PD, using the Medline database and bibliographies in relevant articles. RESULTS: Sleep-related problems specific to PD may occur early and even predate the diagnosis of the disease but are generally more frequent and more severe in patients with advanced PD. These problems can seriously compromise patients' quality of life and lead to impaired functioning in daily activities. Scales designed specifically for the assessment of sleep problems in patients with PD have recently been developed. Evidence base for the treatment of sleep disturbances in PD is poor, and only nocturnal akinesia, excessive day-time sleepiness and rapid eye movement behaviour disorder have been partially addressed. CONCLUSIONS: Sleep disorders associated with PD are a common and under-recognised problem. The assessment of sleep should be part of the routine evaluation of patients with PD, and large-scale controlled therapeutic trials are necessary.

Humans↗
PubMed2006

Development of bioconcrete material using an enrichment culture of novel thermophilic anaerobic bacteria.

In the biosphere, bacteria can function as geo-chemical agents, promoting the dispersion, fractionation and/or concentration of materials. Microbial mineral precipitation is resulted from metabolic activities of microorganisms. Based on this biomineralogy concept, an attempt has been made to develop bioconcrete material incorporating of an enrichment culture of thermophilic and anaerobic bacteria within cement-sand mortar/concrete. The results showed a significant increase in compressive strength of both cement-sand mortar and concrete due to the development of filler material within the pores of cement sand matrix. Maximum strength was observed at concentration 10(5)cell/ml of water used in mortar/concrete. Addition of Escherichia coil or media composition on mortar showed no such improvement in strength.

Anaerobiosis↗
PubMed2005

Variability pattern and correlation studies in Silybum marianum Gaertn.

Phenotypic and genotypic coefficient of variability, heritability in broad sense and genetic advance were determined investigating the characters of 15 accessions of Silybum marianum. Seed yield/plant and number of capsules/plant had highest estimates of genotypic variation, heritability and genetic advance which suggest that direct selection for these traits is suitable for the improvement of this crop. Number of capsules/plant had a significant positive correlation with the number of branches/plant and leaf length (r=0.3398, 0.7547), whereas seed yield/plant had a positive significant correlation with leaf length, stem diameter, capsule diameter and silymarin content (r=0.6830, 0.3140, 0.3484, 0.2925).

Genetic Variation↗
PubMed2005

Role of two toxin-producing plankton and their effect on phytoplankton-zooplankton system--a mathematical study supported by experimental findings.

Plankton is the basis of the entire aquatic food chain. Phytoplankton, in particular, occupies the first trophic level. Plankton performs services for the Earth: it serves as food for marine life, gives off oxygen and also absorbs half of the carbon dioxide from the Earth's atmosphere. The dynamics of a rapid (or massive) increase or decrease of plankton populations is an important subject in marine plankton ecology and generally termed as a 'bloom'. Harmful algal blooms (HABs) have adverse effects on human health, fishery, tourism, and the environment. In recent years, considerable scientific attention has been given to HABs. Toxic substances released by harmful plankton play an important role in this context. In this paper, a mathematical model consisting of two harmful phytoplankton and zooplankton system will be discussed. The analytical findings will be verified through our experimental observations which were carried out on the eastern part of Bay of Bengal for the last three years.

Animals↗
PubMed2005

Effect of chitosan on lipid levels when administered concurrently with atorvastatin--a placebo controlled study.

In a placebo controlled trialthe lipid lowering effects of chitosan, a unique dietary fibre, was assessed when given along with atorvastatin 10 mg in patients with chronic coronary heart disease. Altogether 100 patients were studied. They were randomly allocated in two groups of 50 patients each. Patients of group A received atorvastatin 10 mg before dinner plus 2 g/day chitosan in two divided doses. The groupB patients received atorvastatin 10 mg plus placebo. Patients were followed up for a period of 6 weeks. There was significant reduction in mean body weight in group A patients (3.14% versus 1,29% of body weight, p<0.05). There was also a significant rise in HDL cholesterol value (3.8% versus 1.07%, p=0.02) in group A patients. However, there was no significant reduction in the mean values of total cholesterol, LDL cholesterol and triglyceride in the two groups, although group A patients showed marginally lower values.

Anticholesteremic Agents↗
PubMed2004

Polyphenolics and fat absorption.

OBJECTIVES: To elucidate whether the acute consumption of red wine polyphenolic compounds regulates lipid and lipoprotein metabolism in dyslipidemic postmenopausal women. DESIGN: Eight dyslipidemic postmenopausal women each consumed a mixed meal accompanied by either water, dealcoholized red wine or alcoholic red wine on three separate visits, in a random order, 2 weeks apart. One fasting and six hourly postmeal blood samples were taken and analyzed for plasma apolipoprotein B48 (apoB48; specific marker of chylomicrons (CM) and their remnants (CMR)); total-, LDL- and HDL-cholesterol; triglycerides (TAG); insulin and glucose at each time point. RESULTS: There was a decrease in postprandial apoB48 levels after alcoholic and nonalcoholic red wine consumption compared to water. CONCLUSION: Red wine attenuates postprandial CM and CMR levels in plasma, possibly by delaying the absorption of dietary fat, as suggested by a decrease in plasma apoB48 levels. The reduction of postprandial lipoproteins in circulation after red wine consumption may partly explain the low cardiovascular mortality rates among the French.

Apolipoprotein B-48↗
PubMed2004

Evaluation of the possible role of five enzymes in the metabolism of IBA in mustard aphid, Lipaphis erysimi (Kalt.).

The enzymatic activity of five enzymes viz. Glutathione S-transferases, Esterases, NADH dehydrogenase, NADH oxidase and Glutathione reductase were assessed under the influence of Indole butyric acid (IBA) (400 ppm) in the nymphs (48-52h old) of mustard aphid, Lipaphis erysimi fed on radish plants treated for 13, 25 and 37h. The activity of Glutathione S-transferases, Esterases and NADH dehydrogenase increased compared to that found in the control of the same age group of nymphs and it was concluded that these enzymes might be involved in the metabolism of IBA. The other two enzymes, NADH oxidase and Glutathione reductase showed no significant increase in their activity compared to that in the control of the same age group. It was hypothesized that the latter enzymes do not play any significant role in the metabolism of IBA.

Animals↗
PubMed2003

Dynamical scaling of surface growth in simple lattice models.

We present extensive simulations of the atomistic Edwards-Wilkinson (EW) and Restricted Edwards-Wilkinson (REW) models in 2+1 dimensions. Dynamic finite-size scaling analyses of the interfacial width and structure factor provide the estimates for the dynamic exponent z=1.65+/-0.05 for the EW model and z=2.0+/-0.1 for the REW model. The stochastic contribution to the interface velocity U due to the deposition and diffusion of particles is characterized for both the models using a blocking procedure. For the EW model the time-displaced temporal correlations in U show nonexponential decay, while the temporal correlations decay exponentially for the REW model. Dynamical scaling of the temporal correlation function for the EW model yields a value of z, which is consistent with the estimate obtained from finite-size scaling of the interfacial width and structure factor.

Journal Article↗
PubMed2003

Dynamics of nutrient-phytoplankton interaction in the presence of viral infection.

The present paper deals with the problem of a nutrient-phytoplankton (N-P) populations where phytoplankton population is divided into two groups, namely susceptible phytoplankton and infected phytoplankton. Conditions for coexistence or extinction of populations are derived taking into account general nutrient uptake functions and Holling type-II functional response as an example. It is observed that the three component systems persist when the infected phytoplankton population is not able to consume nutrient.

Biological Transport, Active↗
PubMed2002

Psychopharmacological studies on Tragia involucrata root extract.

The methanol fraction of the root extract of Tragia involucrata was investigated for psychopharmacological activity in rodents. It produced an alteration of behavioural pattern and a reduction in spontaneous motility. A significant potentiation of pentobarbitone-induced sleep, a decrease of body temperature, suppression of the aggressive behaviour pattern and of the conditioned avoidance response (CAR) were observed with the fraction. These suggest that the methanol fraction of the T. involucrata root extract possesses significant central nervous system depressant action.

Aggression↗