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Biomedical subjects

R Puri

Publications and source records attributed to R Puri.

At least 19 recordsLinked to original sources
PubMed1999

Examining the immune response in sentinel lymph nodes of mice and men.

Recently, it was recognized that an immune response develops along one of two major pathways. One leads to a destructive immune response (type 1), while the alternative leads to a nondestructive immune response (type 2). Our studies in animal models suggest that therapeutic vaccines induce a tumor-specific type 1 immune response while ineffective vaccines induce a type 2 response. These results have led us to examine the immune response in sentinel lymph nodes draining tumor vaccines of patients entered onto clinical trials for melanoma, breast and renal cell cancer.

Animals↗
PubMed1998

Substitution of transpedicular screws by hook claws in a vertebrectomy model.

At times one pedicle screw cannot be used in a posterior construct because of morphometric reasons or when the pedicle is fractured intraoperatively. It is not clear from the literature whether and to what extent a construct's stability is compromised by substituting a hook claw for one pedicle screw. A synthetic vertebra model using a hook claw in lieu of a pedicle screw in a compressive and torsional mechanical study is evaluated. Isola screw-based constructs varying in the number of pedicle screws and hook claws were used. To recreate a realistic clinical scenario, transverse connectors and a Harms cage were used as well. In compression, substituting screws with claws did not substantially change the stiffness, whereas substituting one or two pedicle screws with one or two hook claws significantly reduced torsional stiffness. We conclude that using one or two hook claws is a viable alternative for pedicle screws when the latter cannot be used in a clinical situation, especially as an adjunct when the anterior column is reconstructed.

Bone Screws↗
PubMed1997

Regulation of male fertility by pyrimethamine in adult mice.

Studies were carried out to determine the antifertility and reversibility effect of pyrimethamine (PYR) in adult male mice. The parameters mainly included sperm count and motility, fertility, histoarchitecture of testis and testicular cell kinetics quantitatively following oral administration of PYR (50 mg/kg body weight per day) for 30 days. The same parameters were also studied in PYR-treated animals which were allowed to recover for 45 days (recovery group). The results suggest that sperm motility as well as counts were significantly decreased in PYR-treated animals, and the fertility rate fell to zero. Testicular histology as well as germ cell kinetics were altered. However, in the animals of the recovery group, all the parameters studied were more or less similar to those of control animals. The study demonstrates the antifertility as well as reversible efficacy of PYR.

Animals↗
PubMed1996

Ehretianone, a novel quinonoid xanthene from Ehretia buxifolia with antisnake venom activity.

Ehretianone (1), a new quinonoid xanthene, together with known sterols, was isolated from a MeOH extract of the root bark of Ehretia buxifolia. The structure of ehretianone was elucidated as 7-hydroxy-9a alpha-(3-methylbut-2-enyl)-4a alpha,9 alpha-(2-methylprop-2-enyl)-4a, 9a-dihydro-1,4-dioxoxanthene on the basis of spectroscopic data and X-ray crystallographic analysis. The antisnake venom activity of ehretianone against Echis carinatus venom in mice is also reported.

Animals↗
PubMed1995

Differing autonomic response to dobutamine in the presence and absence of ischemia: implications for the autonomic contribution to positive inotropic intervention.

Although it is well recognized that dobutamine is a powerful positive inotropic agent mediating increased myocardial contractility through direct beta-adrenergic stimulation, the mechanism of its overall circulatory effects appears more complex than that which may be ascribed solely to this direct action on the myocardium. Previous investigations have implied that reflex alterations in autonomic balance may contribute significantly to the response to this agent, but direct evidence describing such a response has not been reported. The objective of this investigation was to assess changes in autonomic tone induced by dobutamine in the presence and absence of ischemia through the measurement of heart rate variability in patients undergoing dobutamine stress echocardiography. Of 25 consecutive patients undergoing dobutamine stress echocardiography, 16 were found to have unequivocal evidence for or against the presence of ischemia during dobutamine infusion. Heart rate data from these 16 patients were submitted for spectral analysis of heart rate variability and quantification of parasympathetically governed high-frequency heart rate variability and sympathetically influenced low-frequency heart rate variability. Of the 16 patients nine were not found to have evidence for ischemia (group 1), and seven were found to have echocardiographic findings consistent with dobutamine-induced ischemia (group 2). The two groups significantly differed (p = 0.04) in the change in parasympathetic tone associated with dobutamine with a significant (p = 0.04) increase in parasympathetic tone in group 1 and a numeric decrease in group 2. A significant (p = 0.04) decrease in sympathetic tone was noted in group 1 as reflected by low-frequency heart rate variability with a numeric increase in this measure in group 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Cotrel Dubousset and Wisconsin segmental spine instrumentation: comparison of results in adolescents with idiopathic scoliosis King Type II.

When introduced, the Wisconsin segmental spine instrumentation (WSSI) and the Cotrel Dubousset instrumentation (CDI) were promoted as technical advances for the correction of spinal deformities. Both systems provide acceptable correction and greatly reduce the need for postoperative immobilization. A retrospective study of a homogeneous group of 53 adolescent patients with idiopathic scoliosis with King Type II curves who had reached skeletal maturity at follow-up was conducted to compare and analyze the results of these two systems. Thirty-six of these patients had been operated on using WSSI and 17 had been operated on using CDI. CDI and WSSI were found to be equally effective in treating King Type II curves. No difference was found between the two groups in the fusion rates, spinal balance, time required for surgery, or amount of curve correction. The answer to the question of which system is "better" depends on the surgeon's experience and familiarity with the equipment.

Adolescent↗
PubMed1995

Impact of nutritional supplements on hematological profile of pregnant women.

Eighty one pregnant women (20 +/- 2 weeks of gestation) were assessed for their nutritional status. They were divided into three groups; Group I women (n = 30) were given 200 mg ferrous sulphate (FeSO4) tablet per day for 15 weeks, Group II women (n = 25) were given FeSO4 tablets along with 2,000,000 IU of vitamin A as single dose in beginning of study; and Group III women (n = 26) were not given any supplements and served as controls. To study impact of supplements on hematological profile of pregnant women, Hb, PCV, RBC, TS%, TIBC and serum levels of iron, zinc, copper, manganese and vitamin A were assessed at 20 +/- 2 weeks and 36 +/- 2 weeks of gestation by standard techniques. Pregnant women in Group I (Fe suppl) and group II (Fe + vitamin A suppl) had significantly (p < 0.01) higher Hb, PCV, RBC, TS% and serum iron levels than the controls. Group II had significantly (p < 0.05) higher values of these indices as compared to Group I. Levels of serum zinc, copper, manganese were not affected by supplements. Iron supplements improved the hematological profile of pregnant mothers but Fe + vitamin A supplements were more beneficial.

Drug Therapy, Combination↗
PubMed1994

1H- and 13C-nmr assignments and structural determination of a novel glycoalkaloid from Solanum platanifolium.

Four steroidal glycoalkaloids, solasonine [2], solamargine [3], khasianine [4], and ravifoline [5], with solasodine [1] as the aglycone moiety, have been isolated from Solanum platanifolium. The present study involved the characterization of the novel compound 5 by one- and two-dimensional nmr techniques and has also led to the unambiguous and total 13C- and 1H-nmr assignments of all of these steroidal glycoalkaloids and the direct elucidation of their glycosidic linkages.

Carbohydrate Sequence↗
PubMed1994

Impact of nutrition and health education on rural pre-school children.

Pre-school children (n = 155) belonging to low socio-economic group from eight creches in villages around Chandigarh, were imparted nutrition and health education (NHE) for one year. Appropriate teaching material in the form of songs, rhymes and roleplays were scientifically developed for the purpose. For impact evaluation, objective tools in the form of checklists were formulated and used. NHE on three aspects, i.e., personal hygiene (PH), food hygiene (FH) and recognition of foods (RF) was imparted by Balsevikas (BSs) incharge of the creches, daily in a non-formal manner, for one year and evaluated periodically. On PH only, children of the lowest income group improved significantly. On FH and RF, all children registered significant improvement as these two aspects, were under the direct control of BSs who enthused and involved the children by providing an interacting and stimulating environment. The results are encouraging and indicate the pre-school children are educable in NHE provided participatory and appropriate material and methods are used.

Child Nutrition Sciences↗
PubMed1993

The logic of imaging in spine surgery.

Spinal imaging has rapidly evolved into a complex diagnostic field requiring specialized expertise. While many imaging modalities reveal portions of a topographic map of the spine necessary for surgery, only magnetic resonance imaging emerges as the imaging modality of widest and most efficacious first choice. With the increasing high-technology sophistication of modern imaging modalities, the spine surgeon must become completely conversant with the radiologic data produced by these imaging techniques. The authors present a logical approach to spinal imaging--an algorithm--based on etiologic classification and aimed at conserving medical resources and developing an optimal diagnostic pathway for spine injury and disease. Spine surgeons are urged to incorporate the interpretative insights of radiologists into the diagnostic process.

Algorithms↗
PubMed1992

Clopidogrel inhibits the binding of ADP analogues to the receptor mediating inhibition of platelet adenylate cyclase.

Clopidogrel, like the homologous thienopyridine derivative ticlopidine, selectively inhibits platelet aggregation induced by ADP. We have previously described two nucleotide-binding sites on platelets related to ADP-mediated platelet responses. The first is a high-affinity binding site for 2-methylthio-ADP (2-MeSADP) that is linked to the inhibition of stimulated adenylate cyclase. The second is the 100-kd exofacial membrane protein aggregin, which is labeled by the reactive ADP analogue 5'-p-fluorosulfonylbenzoyl adenosine (FSBA) that is related to shape change and aggregation. We set out to determine if either of these sites is blocked in vivo by clopidogrel or its active metabolite. Six subjects were given clopidogrel (75 mg/day for 10 days) in a double-blind crossover experiment. All of the subjects developed prolonged bleeding times while taking the drug. The rate of onset of the effect on bleeding time varied among subjects. Platelet aggregation induced by ADP or thrombin was significantly impaired by the drug treatment, but no effect was detected on shape change. The incorporation of [3H]FSBA into aggregin was also unaffected. Inhibition of adenylate cyclase by ADP or by 2-MeSADP was greatly reduced in all subjects, and in the case of 2-MeSADP, there was evidence for a noncompetitive effect. Inhibition of adenylate cyclase by epinephrine was unaffected. In the three subjects for whom binding measurements were made, the number of binding sites for [32P]2-MeSADP was reduced from 534 +/- 44 molecules per platelet during control and placebo periods (11 determinations) to 199 +/- 78 molecules per platelet during drug treatment (three determinations). There was no consistent change in the binding affinity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1991

Taste sensitivity in pregnancy.

Taste sensitivity to Phenyl-thio-Carbamide (PTC) and glucose were studied in 150 females during the 3 trimesters of their pregnancy periods. The taste sensitivity to PTC was determined by Harris and Kalmus method. For taste intensity and hedonic evaluation, 7 concentrations of glucose solutions were used. Taste sensitivity to both PTC and glucose increases during the 1st trimester of pregnancy. In comparison to non-pregnant females (from previous study) taste thresholds and hedonics decreases in pregnancy.

Female↗
PubMed1990

In vitro and in vivo antitumor properties of a T-cell clone generated from murine tumor-infiltrating lymphocytes.

We have shown that a T-cell clone derived from murine tumor-infiltrating lymphocytes (TILs) can be established that mediates in vitro and in vivo antitumor effects. Utilizing this clone as a model, we examined the effect of cytokines on T-cell antitumor effector mechanisms in vitro and in vivo. This clone, termed BF-1, was generated by limiting dilution culture of a freshly excised MC-38 tumor, growing it in low levels of interleukin-2 (IL-2), and has been maintained for over 600 days. This clone became specifically cytotoxic for the MC-38 tumor during its first 100 days of culture. Pretreatment of the parental MC-38 tumor cell line with tumor necrosis factor (TNF) and interferon-gamma (IFN-gamma) increased its susceptibility to lysis by the BF-1 TIL line, but not to lysis by lymphokine-activated killer cells, in in vitro cytotoxicity assays. This increased susceptibility of the cytokine-pretreated targets was restricted to the parental tumor (MC-38), since similar pretreatment of MCA-102, MCA-105, or MCA-106 tumors did not render them susceptible to lysis by BF-1 TILs. This increased sensitivity to lysis in vitro was not the result of a change in the expression of major histocompatibility complex class I molecules. In experiments testing the ability of TILs to treat established lung metastases, the combination of TNF, IFN-gamma, IL-2, and TILs was shown to increase significantly the antitumor properties of this therapy when compared to TILs and IL-2. This result demonstrates that combinations of lymphokines, which when administered alone do not affect micrometastatic tumor burdens (TNF, IFN-gamma), can synergize with cellular immunotherapy in the treatment of established tumor burdens and may have applicabilities to the treatment of cancer in humans.

Adenocarcinoma↗
PubMed1987

Hypothalamic control of nocireceptive and other neurons in the marginal layer of the dorsal horn of the medulla (trigeminal nucleus caudalis) in the rat.

The effect of electrical stimulation of the preoptic area of the hypothalamus on the discharge of neurones in the marginal layer (lamina I) of the trigeminal nucleus caudalis was studied in the anaesthetised rat. There was a powerful suppression of the discharge evoked by noxious thermal stimuli in 49/49 specific nociceptor driven (nocireceptive) neurones. The inhibitory effect increased with graded increases in the intensity of preoptic stimulation. Stimulation, however, produced only a small reduction in the discharge of 14/17 cold receptive neurones. Thresholds for producing suppression of cold receptive neurones were generally higher than those for nocireceptive neurones. There was no effect on the activity of 12/12 low threshold mechanoreceptive neurones. The inhibitory action generated on the activity of nocireceptive neurones was reduced by electrolytic lesions in the nucleus raphe magnus (NRM) or the nucleus paragigantocellularis lateralis (PGCL) or the dorsolateral and ventrolateral periaqueductal gray matter (PAG). Lesions made in the ventral or dorsal aspect of PAG were, however, ineffective in reducing the suppression. It is suggested that the powerful descending inhibitory control of nociceptive transmission in the trigeminal nucleus caudalis is one of the neuronal mechanisms mediating analgesia from the preoptic area of the hypothalamus.

Action Potentials↗