Biomedical subjects

S Rajaram

Publications and source records attributed to S Rajaram.

At least 19 recordsLinked to original sources

PubMed2006

Role of the anterior cingulate and medial orbitofrontal cortex in processing drug cues in cocaine addiction.

Our goal in the current report was to design a new functional magnetic resonance imaging (fMRI) task to probe the role of the anterior cingulate cortex (ACC) and orbitofrontal cortex (OFC) in processing of salient symptom-related cues during the simultaneous performance of an unrelated task in drug-addicted persons. We used a novel fMRI color-word drug Stroop task in 14 individuals with cocaine use disorders; subjects had to press for color of drug vs. matched neutral words. Although there were no accuracy or speed differences between the drug and neutral conditions in the current sample of subjects, drug words were more negatively valenced than the matched neutral words. Further, consistent with prior reports in individuals with other psychopathologies using different Stroop fMRI paradigms, our more classical color-word Stroop design revealed bilateral activations in the caudal-dorsal anterior cingulate cortex (cdACC) and hypoactivations in the rostro-ventral anterior cingulate cortex/medial orbitofrontal cortex (rACC/mOFC). A trend for larger rACC/mOFC hypoactivations to the drug than neutral words did not survive whole-brain corrections. Nevertheless, correlation analyses indicated that (1) the more the cdACC drug-related activation, the more negative the valence attributed to the drug words (r=-0.86, P<0.0001) but not neutral words; and (2) the more the rACC/mOFC hypoactivation to drug minus neutral words, the more the errors committed specifically to the drug minus neutral words (r=0.85, P<0.0001). Taken together, results suggest that this newly developed drug Stroop fMRI task may be a sensitive biobehavioral assay of the functions recruited for the regulation of responses to salient symptom-related stimuli in drug-addicted individuals.

Adult↗

PubMed2006

A comparative study of body potassium content in males and females at Kalpakkam (India).

A group of 300 subjects of both sexes were measured for total body potassium content using a shadow shield whole-body counting system at Kalpakkam (India). The mean body potassium content for males was 1.7 +/- 0.5 g kg(-1) body weight and 1.5 +/- 0.5 g kg(-1) body weight for females. The body potassium content varies inversely with age as well as with the body weight for both the sexes. However, the total body potassium varies directly with body-build index for both males and females. The mean annual dose due to (40)K for males and females was found to be 149 +/- 44 and 132 +/- 41 uGy, respectively.

Adolescent↗

PubMed2005

Do individual and program factors matter in the utilization of maternal care services in rural India?: a theoretical approach.

Current studies on the utilization of maternal care services in India focus on individual factors. In the present study, we use the theoretical model developed by Andersen and Newman [1973. Societal and individual determinants of medical care utilization in the United States. Milbank Memorial Fund Quarterly, 51(1), 95-124] to understand the utilization of maternal care services in rural areas of India. This theoretical model uses individual and welfare program-or system factors-to study health care utilization. Data collected through the National Family Health Survey-2 are used in the present study. The results suggest that in addition to individual characteristics, program and system factors influence the utilization of maternal care in rural areas. Program factors, particularly educational activities promoting the benefits of maternal care services carried out through mahila mandal and anganwadi centers, are important in increasing the use of maternal care services in rural areas. Additionally, the results indicate that the mere presence of a private health care facility need not necessarily improve utilization. Increase in utilization is observed among households if the health worker visited these households during pregnancy. More state-specific studies incorporating both program and individual characteristics are recommended to further strengthen our understanding of the utilization of health care services in general and maternal care services specifically.

Adolescent↗

PubMed2005

Pregnancy in an achondroplastic dwarf: a case report.

Achondroplasia is a rare disorder occurring 1 in 1 5,000 to 1 in 40,000 live births. It is, however, the commonest cause of short-limbed dwarfism. It is a genetic disorder and inherited as an autosomal dominant trait but most cases (80%) are due to mutations of fibroblast growth factor receptor 3 (FGFR3). These individuals have normal mental and sexual development, and life span may be normal. Certain gynaecological problems like infertility, menorrhagia, dysmenorrhoea, leiomyomata and early menopause are more common in these patients. Information regarding obstetric behaviour in achondroplastic females is scarce in literature. However, problems such as pre-eclampsia, polyhydramnios, respiratory compromise, contracted pelvis necessitating lower section caesarean section, prematurity and foetal wastage, etc, have been reported. General anaesthesia is preferred to regional anaesthesia because of the spinal abnormalities. There is increased neonatal mortality due to hydrocephalus and thoracic cage abnormality. Such a patient is considered high risk in terms of anaesthesia and obstetric outcome and there is enough room for prenatal counselling and diagnosis. Here a case of achondroplasia with pregnancy is reported. The patient, an achondroplastic dwarf presented with 30 weeks pregnancy. She was prenatally screened with ultrasonography to rule out affection in baby. She had a caesarean section for contracted pelvis.

Achondroplasia↗

PubMed2004

A survey on current attitude of practicing physicians upon usage of antimicrobial agents in southern part of India.

CONTEXT: Antimicrobial resistance is a serious public health concern worldwide. Inappropriate prescribing, including the wrong drug, incorrect dose/duration, and poor compliance, contributes to it. OBJECTIVE: To identify factors determining the attitudes and practices of prescribers regarding antibiotic usage and to suggest measures that contain antibiotic resistance. DESIGN AND SETTING: With a convenient sample, general practitioners and specialists of both sexes from 5 districts of Tamilnadu state, India, were approached for the study. A slightly modified, self-administered, anonymous questionnaire of the Alliance for the Prudent Use of Antibiotics was used. The deciding factors to prescribe an antibiotic and the reasons for the attitude to prescribe a broad-spectrum antibiotic were elicited. RESULTS: Out of the 285 participants 120, 110, and 47 practiced at city, semiurban, and rural areas, respectively. The responses were graded with a total possible score of 150. There was no significant difference between men and women or between specialist and nonspecialists in scores. The majority believed that antibiotics are overprescribed. Purulent discharge (65%), antibiotic-resistance concerns (48%), fever (40%), and patient satisfaction (29%) were the strong influences to prescribe an antibiotic. Similar reasons were cited for the belief of prescribing a broad-spectrum antibiotic. The 3 most commonly prescribed antimicrobials were amoxicillin (21%), ciprofloxacin (18%), and co-trimoxazole (11%). About 42% used an antibiogram only to the extent of less than 10%. CONCLUSION: Patient requests/expectations, patient satisfaction, purulent discharge, and fever strongly pressurized practitioners to prescribe antibiotics. Patient and time pressures, diagnostic and treatment uncertainties, and the poor utilization and/or ill-affordable antibiogram facility all point to an urgent, multidimensional approach to contain antibiotic resistance.

Anti-Infective Agents↗

PubMed2003

An analysis of childhood malnutrition in Kerala and Goa.

Improved child health and survival are considered universal humanitarian goals. In this respect, understanding the nutritional status of children has far-reaching implications for the better development of future generations. The present study assessed, first, the nutritional status of children below 5 years using the three anthropometric measures weight-for-age, height-for-age and weight-for-height in two states of India, Kerala and Goa. Secondly, it examined the confounding factors that influence the nutritional status of children in these states. The NFHS-I data for Kerala and Goa were used. The results showed that the relative prevalence of underweight and wasting was high in Kerala, but the prevalence of stunting was medium. In Goa, on the other hand, the relative prevalence of wasting and underweight was very high, and that of stunting was high. Both socioeconomic and family planning variables were significantly associated with malnutrition in these states, but at varied levels. The study recommends more area-specific policies for the development of nutritional intervention programmes.

Anthropology↗

PubMed2001

Addiction changes orbitofrontal gyrus function: involvement in response inhibition.

We used the Stroop task as a measure of the ability to inhibit a prepotent response tendency and examined its association with relative glucose metabolism in selected prefrontal brain regions in cocaine addicts, alcoholics, and controls (17 per group). Results revealed that for the substance abusers, higher orbitofrontal gyrus (OFG) activation was associated with lower conflict (higher score; r = 0.32, p < 0.05). For the controls, higher OFG activation was associated with higher conflict (lower score; r = -0.42, p < 0.05). Thus, at baseline, increased relative activation of the OFG is associated with worse performance in controls and better performance in substance abusers on the Stroop task, suggesting reversal of the role of the OFG as a function of addiction.

Adult↗

PubMed2001

A monounsaturated fatty acid-rich pecan-enriched diet favorably alters the serum lipid profile of healthy men and women.

Frequent consumption of nuts is associated with decreased risk of cardiovascular disease. We investigated the effect of pecans rich in monounsaturated fat as an alternative to the Step 1 diet in modifying serum lipids and lipoproteins in men and women with normal to moderately high serum cholesterol. In a single-blind, randomized, controlled, crossover feeding study, we assigned 23 subjects (mean age: 38 y; 9 women, 14 men) to follow two diets, each for 4 wk: a Step I diet and a pecan-enriched diet (accomplished by proportionately reducing all food items in a Step I diet by one fifth for a 20% isoenergetic replacement with pecans). The percentage of energy from fat in the two diets was 28.3 and 39.6%, respectively. Both diets improved the lipid profile; however, the pecan-enriched diet decreased both serum total and LDL cholesterol by 0.32 mmol/L (6.7 and 10.4%, respectively) and triglyceride by 0.14 mmol/L (11.1%) beyond the Step I diet, while increasing HDL cholesterol by 0.06 mmol/L (2.5 mg/dL). Serum apolipoprotein B and lipoprotein(a) decreased by 11.6 and 11.1%, respectively, and apolipoprotein A1 increased by 2.2% when subjects consumed the pecan compared with the Step I diet. These differences were all significant (P < 0.05). A 20% isoenergetic replacement of a Step I diet with pecans favorably altered the serum lipid profile beyond the Step I diet, without increasing body weight. Nuts such as pecans that are rich in monounsaturated fat may therefore be recommended as part of prescribed cholesterol-lowering diet of patients or habitual diet of healthy individuals.

Cross-Over Studies↗

PubMed2001

The effects of attention on perceptual implicit memory.

Reports on the effects of dividing attention at study on subsequent perceptual priming suggest that perceptual priming is generally unaffected by attentional manipulations as long as word identity is processed. We tested this hypothesis in three experiments by using the implicit word fragment completion and word stem completion tasks. Division of attention was instantiated with the Stroop task in order to ensure the processing of word identity even when the participant's attention was directed to a stimulus attribute other than the word itself. Under these conditions, we found that even though perceptual priming was significant, it was significantly reduced in magnitude. A stem cued recall test in Experiment 2 confirmed a more deleterious effect of divided attention on explicit memory. Taken together, our findings delineate the relative contributions of perceptual analysis and attentional processes in mediating perceptual priming on two ubiquitously used tasks of word fragment completion and word stem completion.

Adult↗

PubMed2000

The sequence and associated null phenotype of a C. elegans neurocalcin-like gene.

The neuronal calcium sensor (NCS) proteins belong to a subfamily of the EF-hand calcium binding proteins. These proteins are primarily expressed in the nervous system and currently include more than 20 members across species [Nakayama et al., J Mol Evol 34:416-448, 1992]. Two homologues of the ncs genes, Ce-ncs-1 and Ce-ncs-2, have recently been identified in the nematode C. elegans. Here we report the cDNA sequence of a third C. elegans ncs homologue, Ce-ncs-3. We demonstrate that a null mutation in this gene caused by a large deletion in the locus does not confer a visible phenotype in C. elegans. This, in addition to the strong homology between Ce-NCS-3 and the other C. elegans NCS proteins, may indicate functional redundancy between the three genes.

Alleles↗

PubMed2000

Conceptual fluency selectively influences knowing.

Research shows that Remember and Know judgments are effective measures of recollective experience. This article shows that Know responses can be selectively affected by fluency of processing that is created using a conceptual manipulation. In a recognition test, studied and nonstudied words were preceded by semantically related or unrelated primes. Participants gave significantly more Know judgments to items with related primes than unrelated primes but Remember responses were unaffected. Know responses are discussed in terms of familiarity assumed to arise from fluency of processing which, in turn, may be created through various sources including conceptual processes.

Cognition↗

PubMed2000

Acquisition and transfer of new verbal information in amnesia: retrieval and neuroanatomical constraints.

Four experiments examined new associative learning in amnesia by contrasting the performance of 2 amnesic participants-1 (C.C.) with basal forebrain damage and the other (R.H.) with medial temporal lobe damage--and 3 controls. Both amnesic individuals were severely impaired on explicit memory measures but showed intact perceptual priming. On the new associations measures, only C.C., not R.H., exhibited learning by producing correct targets (HIJACKER) in the absence of perceptual cues for them (e.g., STAFF shot ???). When the perceptual cue (e.g., MEDICINE cured _I_C_P) was provided, both C.C. and R.H. showed learning. Transfer to information containing conceptually related targets (e.g., TERRORIST or BELCH) was reliably observed only in C.C. This finding was replicated with further reduction in perceptual overlap across original (LIGHTNING torched JUNGLE) and transfer (LIGHTNING burned WILDERNESS) sentences. Together, these findings delineate the role of experimental conditions, severity of amnesia, and different neuroanatomical structures in mediating new verbal learning in amnesia.

Adult↗

PubMed2000

On associations between computers and restaurants: rapid learning of new associations on a conceptual implicit memory test.

A novel event-based conceptual implicit memory test was designed to tap the development of new associations between objects and ad hoc categories. At study, participants were presented with a plausible story that linked an incongruous object (computer) with an ad hoc category (restaurant). At test, participants judged whether a given object was typically found in a restaurant. In Experiment 1, judgment time was significantly slower for the incongruous object (computer) when the story had previously linked the computer to the restaurant, relative to when it had not. Experiment 2 replicated this effect and ruled out the alternative interpretation that this interference effect was attributable to a general slowing of responses to all studied items. Unlike in prior studies, this demonstration of associative priming cannot be attributed to perceptual priming or to test awareness in memory-intact participants. The paradigm therefore offers a unique opportunity to study single-trial conceptual learning in memory-intact and memory-impaired populations.

Adult↗

PubMed1999

Anti-diarrhoeal evaluation of Clerodendrum phlomidis Linn. leaf extract in rats.

A study was undertaken to evaluate the effect of methanolic extract of leaves of Clerodendrum phlomidis Linn. (MECP) (Family: Verbenaceae) for its anti-diarrhoeal potential against several experimental models of diarrhoea in Wistar albino rats. MECP showed significant inhibitory activity against castor oil induced diarrhoea and PGE2 induced enteropooling in rats. The extract also showed a significant reduction in gastrointestinal motility in charcoal meal test in rats. The results obtained establish the efficacy and substantiated the folklore claim as an anti-diarrhoeal agent.

Animals↗

PubMed1999

A stomatin and a degenerin interact to control anesthetic sensitivity in Caenorhabditis elegans.

The mechanism of action of volatile anesthetics is unknown. In Caenorhabditis elegans, mutations in the gene unc-1 alter anesthetic sensitivity. The protein UNC-1 is a close homologue of the mammalian protein stomatin. Mammalian stomatin is thought to interact with an as-yet-unknown ion channel to control sodium flux. Using both reporter constructs and translational fusion constructs for UNC-1 and green fluorescent protein (GFP), we have shown that UNC-1 is expressed primarily within the nervous system. The expression pattern of UNC-1 is similar to that of UNC-8, a sodium channel homologue. We examined the interaction of multiple alleles of unc-1 and unc-8 with each other and with other genes affecting anesthetic sensitivity. The data indicate that the protein products of these genes interact, and that an UNC-1/UNC-8 complex is a possible anesthetic target. We propose that membrane-associated protein complexes may represent a general target for volatile anesthetics.

Anesthetics↗

PubMed1998

Control of anesthetic response in C. elegans.

We describe the use of the animal model C. elegans to understand how the volatile anesthetics work at the molecular level. Mutations in several different genes can profoundly change the behavior of this animal under volatile anesthetics. Protein products of two of these genes are discussed. One gene is an integral membrane protein thought to regulate ion channels. The other is a subunit of the first protein complex of the electron transport chain.

Anesthetics, Inhalation↗

PubMed1998

Unc-1: a stomatin homologue controls sensitivity to volatile anesthetics in Caenorhabditis elegans.

To identify sites of action of volatile anesthetics, we are studying genes in a functional pathway that controls sensitivity to volatile anesthetics in the nematode Caenorhabditis elegans. The unc-1 gene occupies a central position in this pathway. Different alleles of unc-1 have unique effects on sensitivity to the different volatile anesthetics. UNC-1 shows extensive homology to human stomatin, an integral membrane protein thought to regulate an associated ion channel. We postulate that UNC-1 has a direct effect on anesthetic sensitivity in C. elegans and may represent a molecular target for volatile anesthetics.

Amino Acid Sequence↗

PubMed1998

The phenomenology of false memories: episodic content and confidence.

Three experiments investigated the phenomenology of false memories in J. D. Bransford and J. J. Frank's (1971) semantic integration paradigm using Remember-Know judgments and confidence ratings. Findings included high rates of Remember false alarms that increased with greater integrative demands, a dissociation between Remember and Know judgments in the standard Bransford and Franks condition, and similar patterns of Remember and Know judgments in a condition where semantic integrative processes were weakened. Confidence ratings were consistently higher for Remember judgments except where integrative processes were greatest. These results are discussed in terms of the phenomenology of true and false memory for episodes.

Adult↗