PubMed Health⌕ Search

Biomedical subjects

R Rajesh

Publications and source records attributed to R Rajesh.

32 records · Page 2Linked to original sources
PubMed2003

Food restriction attenuates blood lipid peroxidation in carbon tetrachloride-intoxicated rats.

OBJECTIVE: We investigated whether food restriction offers protection against the toxicity of carbon tetrachloride (CCl(4)) and, if so, at what percentage of restriction. METHODS: The effects of food restriction (75% and 50% of food intake) and food restriction followed by CCl(4) treatment on lipid peroxidation and antioxidant enzymes were studied in female Wistar rats. A single dose of CCl(4) (3 mL/kg of body weight, subcutaneous) was administered at the end of the 30-d feeding period. RESULTS: The magnitude of increase in lipid peroxidation was less after CCl(4) treatment in food-restricted animals than in animals fed ad libitum (control), whereas alanine transaminase, aspartate transaminase, and alkaline phosphatase activities in plasma were enhanced due to CCl(4) treatment. The magnitude of increase in the marker enzymes was less in food-restricted animals than in control animals. Erythrocytes from food-restricted rats were more resistant to hydrogen peroxide-induced peroxidation than were those from control rats. The activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione-S-transferase were higher in food-restricted animals. CONCLUSIONS: The present results suggested that food restriction can minimize drug-related increases in peroxidation and protect the system against drug toxicity, presumably by induction of antioxidant potential.

Alanine Transaminase↗
PubMed2003

Pyridoxine-dependent seizures: a review.

Pyridoxine-dependent seizure is a rare autosomal recessive disorder that usually presents with neonatal intractable seizures. This syndrome results from an inborn abnormality of the enzyme glutamic acid decarboxylase, which results in reduced pyridazine-dependent synthesis of the inhibitory neurotransmitter gamma amino butyric acid. The full range of symptomatology is unknown; but can be associated with autism, breath holding and severe mental retardation, bilious vomiting, transient visual agnosia, severe articulatory apraxia motor dyspraxia, microcephaly and intrauterine seizures. Parenteral pyridine injection test is a highly effective and reproducible test in confirming the diagnosis. Pyridoxine should be administered as a diagnostic test in all cases of convulsive disorders of infancy in which no other diagnosis is evident. Epileptic seizure discharges subside within 2-6 minutes after the intravenous injection of 50-100 mg of pyridaoxine. Once the diagnosis is confirmed, maintenance therapy should be continued indefinitely and doses increased with age or intercurrent illnesses. The maintenance dose of Bg needed is still not clear. There is a relatively wide range for the daily B6 dose necessary to control the seizure i.e., 10-200 mg/day.

Child↗
PubMed2003

Intraoral actinomycotic lesion: a case report.

Actinomycosis often referred to, as the chameleon of the head and neck pathology is a rare disease, uncommon in children. This article refers to a case of intraoral actinomycotic lesion of the palate in a child following a rare aetiology, the relevant literature, clinical course and its successful resolution.

Actinomycosis↗
PubMed2003

Primary antiphospholipid antibody syndrome presenting as venous infarct and deep vein thrombosis.

We report the case of a young lady with primary antiphospholipid antibody syndrome, who had two spontaneous abortions and cerebral venous thrombosis and subsequently deep vein thrombosis of the leg veins. Three classes of antiphospholipid antibodies (IgG, IgM, IgA) were elevated. There was no clinical or laboratory evidence for other autoimmune or systemic illnesses. We are presenting the case due to the rarity of the same.

Abortion, Spontaneous↗
PubMed2002

Kang-Redner small-mass anomaly in cluster-cluster aggregation.

The large-time small-mass asymptotic behavior of the average mass distribution P(m,t) is studied in a d-dimensional system of diffusing aggregating particles for 1< or =d< or =2. By means of both a renormalization group computation as well as a direct resummation of leading terms in the small-reaction-rate expansion of the average mass distribution, it is shown that P(m,t) approximately (1/t(d))(m(1/d)/sqrt[t])(e(KR)) for m<<t(d/2), where e(KR)=epsilon+O(epsilon(2)) and epsilon=2-d. In two dimensions, it is shown that P(m,t) approximately ln(m)ln(t)/t(2) for m<<t/ln(t). Numerical simulations in two dimensions supporting the analytical results are also presented.

Journal Article↗
PubMed2002

Aggregate formation in a system of coagulating and fragmenting particles with mass-dependent diffusion rates.

The effect of introducing a mass-dependent diffusion rate approximately m(-alpha) in a model of coagulation with single-particle breakup is studied both analytically and numerically. The model with alpha=0 is known to undergo a nonequilibrium phase transition as the mass density in the system is varied from a phase with an exponential distribution of mass to a phase with a power-law distribution of masses in addition to a single infinite aggregate. This transition is shown to be curbed, at finite densities, for all alpha>0 in any dimension. However, a signature of this transition is seen in finite systems in the form of a large aggregate and the finite-size scaling implications of this are characterized. The exponents characterizing the steady-state probability that a randomly chosen site has mass m are calculated using scaling arguments. The full probability distribution is obtained within a mean-field approximation and found to compare well with the results from numerical simulations in one dimension.

Journal Article↗
PubMed2002

Effect of spatial bias on the nonequilibrium phase transition in a system of coagulating and fragmenting particles.

We examine the effect of spatial bias on a nonequilibrium system in which masses on a lattice evolve through the elementary moves of diffusion, coagulation, and fragmentation. When there is no preferred directionality in the motion of the masses, the model is known to exhibit a nonequilibrium phase transition between two different types of steady state, in all dimensions. We show analytically that introducing a preferred direction in the motion of the masses inhibits the occurrence of the phase transition in one dimension, in the thermodynamic limit. A finite-size system, however, continues to show a signature of the original transition, and we characterize the finite-size scaling implications of this. Our analysis is supported by numerical simulations. In two dimensions, bias is shown to be irrelevant.

Journal Article↗
PubMed2002

Adsorption and collapse transitions in a linear polymer chain near an attractive wall.

We deduce the qualitative phase diagram of a long flexible neutral polymer chain immersed in a poor solvent near an attracting surface using phenomenological arguments. The actual positions of the phase boundaries are estimated numerically from series expansion up to 19 sites of a self-attracting self-avoiding walk in three dimensions. In two dimensions, we calculate phase boundaries analytically in some cases for a partially directed model. Both the numerical and analytical results corroborate the proposed qualitative phase diagram.

Journal Article↗
PubMed2001

Exact tagged particle correlations in the random average process.

We study analytically the correlations between the positions of tagged particles in the random average process, an interacting particle system in one dimension. We show that in the steady state, the mean-squared autofluctuation of a tracer particle grows subdiffusively sigma(2)0(t) approximately t(1/2) for large time t in the absence of external bias but grows diffusively sigma(2)0(t) approximately t in the presence of a nonzero bias. The prefactors of the subdiffusive and diffusive growths, as well as the universal scaling function describing the crossover between them, are computed exactly. We also compute sigma(2)(r)(t), the mean-squared fluctuation in the position difference of two tagged particles separated by a fixed tag shift r in the steady state and show that the external bias has a dramatic effect on the time dependence of sigma(2)(r)(t). For fixed r,sigma(2)(r)(t) increases monotonically with t in the absence of bias, but has a nonmonotonic dependence on t in the presence of bias. Similarities and differences with the simple exclusion process are also discussed.

Journal Article↗
PubMed2001

Exact phase diagram of a model with aggregation and chipping.

We reexamine a simple lattice model of aggregation in which masses diffuse and coalesce upon contact with rate 1 and every nonzero mass chips off a single unit of mass and adds it to a randomly chosen neighbor with rate w. The dynamics conserves the average mass density rho and in the stationary state the system undergoes a nonequilibrium phase transition in the (rho-w) plane across a critical line rho(c)(w). In this paper, we show analytically that in arbitrary spatial dimensions rho(c)(w)=sqrt[w+1]-1 exactly and hence, remarkably, is independent of dimension. We also provide direct and indirect numerical evidence that strongly suggests that the mean field asymptotic results for the single site mass distribution function and the associated critical exponents are superuniversal, i.e., independent of dimension.

Journal Article↗
PubMed2000

Exact calculation of the spatiotemporal correlations in the takayasu model and in the q model of force fluctuations in bead packs

We calculate exactly the two point mass-mass correlations in arbitrary spatial dimensions in the aggregation model of Takayasu. In this model, masses diffuse on a lattice, coalesce upon contact, and adsorb unit mass from outside at a constant rate. Our exact calculation of the variance of mass at a given site proves explicitly, without making any assumption of scaling, that the upper critical dimension of the model is 2. We also extend our method to calculate the spatiotemporal correlations in a generalized class of models with aggregation, fragmentation, and injection, which include, in particular, the q model of force fluctuations in bead packs. We present explicit expressions for the spatiotemporal force-force correlation function in the q model. These can be used to test the applicability of the q model in experiments.

Journal Article↗
PubMed2000

A clinical profile to assess the potential risk factors for cleft lip and palate.

Cleft lip and palate is one of the most common malformations in man. Although the subject of a great deal of investigation, etiologic factors contributing to these congenital deformities remain largely unknown. Various factors like race, sex, parental age at the time of conception etc. have been listed as the exogenous factors. This article strives to project any significant relationship of these factors to cleft lip and cleft palate.

Adolescent↗
PubMedDate not supplied

Prenatal screening for neural tube defects.

Neural tube defects are common birth defects with a prevalence of 4-15 per 10000 live-births. Prenatal diagnosis of neural tube defects has implications in obstetric management and many countries have successfully reduced their incidence by adopting nationwide preventive programmes. It is generally accepted that failure of the neural tube to close causes these defects. Periconceptional use of antiepileptic drugs such as valproate and carbamazepine and deficiency of folate is associated with a high incidence of these defects. Procedures for prenatal diagnosis include: (i) assessment of serum markers such as maternal serum alpha-foetoprotein and acetylcholinesterase activity; (ii) prenatal ultrasonography; and (iii) amniocentesis in selected cases. The levels of these two serum markers are increased in neural tube defects and a value of more than two multiples of the median is considered significant. The optimal time for serum screening is 10-18 weeks. In the case of serum markers it is important to apply normative data standardized for a laboratory and the duration of gestation. Antenatal ultrasonography is a simple, non-invasive and widely available test which has a similar sensitivity with lower false positivity compared to serum markers. Early diagnosis by ultrasound demands skill and experience in the procedure. Levels of amniotic fluid alpha-foetoprotein and acetylcholinesterase activity are elevated in neural tube defects. However, increased iatrogenic foetal loss is a disadvantage of this technique. Detailed counselling of the couple needs to be an integral part of the prenatal screening programme.

Female↗