PubMed Health⌕ Search

Biomedical subjects

R Raghunathan

Publications and source records attributed to R Raghunathan.

At least 19 recordsLinked to original sources
PubMed2005

Effect of polymeric black tea polyphenols on benzo(a)pyrene [B(a)P]-induced cytochrome P4501A1 and 1A2 in mice.

The chemopreventive activity of green tea polyphenols (GTPs) is, in part, due to modulation of cytochrome P450s (CYPs). To investigate the enzyme modulatory properties of major black tea polyphenols, the effect of decaffeinated black tea extract (DBTE) or polymeric black tea polyphenol (PBP) mix was studied on CYP1A1 and CYP1A2 in mouse tissues. Animals receiving 2.5% DBTE or 1% PBP mix or drinking water (15 days) were challenged with single oral benzo(a)pyrene (B(a)P) (1 mg/mouse) treatment on the 14th day. Liver and lung microsomes isolated after 24 h were analysed for CYP1A1 and CYP1A2, using biochemical substrate(s) and Western blot analysis. Treatment with 2.5% DBTE or 1% PBP mix did not significantly alter the basal activity and level of CYP1A1 and CYP1A2, whereas pretreatment with 2.5% DBTE or 1% PBP mix resulted in a significant decrease in both the activity and the level of B(a)P-induced CYP1A1 and CYP1A2 in liver and lungs. The PBP mix possesses enzyme modulatory properties exhibited by monomeric GTPs.

Administration, Oral↗
PubMed2003

Synthesis, antimicrobial and antifungal activity of a new class of spiro pyrrolidines.

A new class of spiro pyrrolidines, dispiro[oxindole-cyclohexanone]pyrrolidines, dispiro[oxindole-tetrahydronaphthalen-1-one]pyrrolidines, dispiro[oxindole-arylidene-cyclohexanone]pyrrolidines, dispiro[oxindole-hexahydro-indazole]pyrrolidines, and spiro[butenolide]pyrrolidines, have been screened for their antibacterial and antifungal activity against ten human pathogenic bacteria and four dermatophytic fungi. They were found to have antimicrobial and antifungal activity compounds against various pathogens except Bacillus subtilis. The spiro pyrrolidinines were synthesized by the regioselective 1,3-dipolar cycloaddition reaction of azomethine ylides generated either from isatin and sarcosine or from aziridine. The azomethine ylide so generated reacted with various dipolarophiles such as 2-arylidene-cyclohexanones, 2-arylidene-tetrahydronapthalen-1-ones, 2,6-bis(arylmethylidene)cyclohexanones and 3-arylidene-5-phenyl- butenolides.

Anti-Bacterial Agents↗
PubMed2002

Cancer-related anemia in a rat model: alpha2-macroglobulin from Yoshida sarcoma shortens erythrocyte survival.

Implantation of Yoshida ascites sarcoma in rats was found to lead to a reduction in the hemoglobin content, the erythrocyte count and the packed cell volume of blood to 30% of normal in 4 d; however, there was no decrease in the mean cell hemoglobin, the mean cell volume and the mean corpuscular hemoglobin concentration, or suppression of erythropoiesis. The red cells from the circulation of tumor-bearing animals, tagged with (51)Cr and injected intravenously in normal rats, showed significantly faster clearance than normal. The erythrocytes contaminating the tumor ascites exhibited extremely short survival, suggesting that one or more secreted tumor product(s) may be responsible for the effect. Incubation of red cells from normal rats in the cell-free ascites fluid, or with an isoform of alpha2-macroglobulin purified from it, also led to reduction in the survival; but the ascites fluid depleted specifically of alpha2-macroglobulin was without any effect. The erythrocytes exhibiting reduced survival showed a proportionate decrease in their cellular deformability. The study identifies a tumor product that is directly responsible for the causation of anemia in the host, and the mechanism by which it does so.

Anemia↗
PubMed2001

3',4'-Bis(4-chlorophenyl)spiro[chroman-3,5'(4'H)-isoxazol]-4-one.

The title compound, C(23)H(15)Cl(2)NO(3), crystallizes with two independent molecules in the asymmetric unit. The chromanone moiety consists of a benzene ring fused with a six-membered heterocyclic ring which adopts a sofa conformation. The five-membered spiroisoxazoline ring is in an envelope conformation. The p-chlorophenyl rings bridged by the five-membered ring are nearly perpendicular to each other. The chromanone moiety of one molecule packs into the cavity formed by the p-chlorophenyl rings of a second molecule through the formation of C-H.pi interactions. The structure is stabilized by weak C-H.O, C-H.Cl and C-H.pi interactions.

Journal Article↗
PubMed2000

Thoracoscopy versus open lung biopsy in the diagnosis of interstitial lung disease: a randomised controlled trial.

BACKGROUND: Some patients with diffuse lung disease require a lung biopsy for diagnosis. This study is aimed to compare the clinical results and the efficacy of video-assisted thoracoscopic lung biopsy with the open lung biopsy method for the diagnosis of interstitial lung disease. From January 1996 to December 1998, 61 patients were referred for diagnostic lung biopsy. Thirty two patients were randomly allocated to have a thoracoscopic lung biopsy and twenty nine had an open lung biopsy. Subsequently, various factors were analyzed and compared in both groups. RESULTS: There was no difference between the groups in age and pulmonary function test. Median operative time was 45 minutes for the thoracoscopic biopsies and 60 minutes for the open biopsies (P = 0.009). Median amount of analgesia (Demerol) in the first 24 hours postoperatively was 75 mg. for thoracoscopic biopsies and 150 mg. for open biopsies (P < 0.001). Median duration of insertion of a chest tube in days and 24 hours of pleural drainage was not statistically significant between the two groups. Duration of hospital stay was significantly less for the thoracoscopic biopsy (3 days) compared with an open biopsy (5 days) (P < 0.001). The diagnostic yield of each method was comparable (thoracoscopic biopsy 31/32; open biopsy 27/29) (P = 0.3). Complications occurred in 6/29 of patients undergoing open biopsies and 3/32 patients undergoing thoracoscopic lung biopsies (p = 0.28). There were 2 deaths among patients who had an open lung biopsy. CONCLUSION: Thoracoscopic lung biopsy has some clinical advantages over open biopsy. These findings suggest that thoracoscopic lung biopsy is an acceptable alternative to open lung biopsy for the diagnosis of diffuse interstitial lung diseases.

Adult↗
PubMed1999

All Negative Moods Are Not Equal: Motivational Influences of Anxiety and Sadness on Decision Making.

Affective states of the same valence may have distinct, yet predictable, influences on decision processes. Results from three experiments show that, in gambling decisions, as well as in job-selection decisions, sad individuals are biased in favor of high-risk/high-reward options, whereas anxious individuals are biased in favor of low-risk/low-reward options. We argue that these biases occur because anxiety and sadness convey distinct types of information to the decision-maker and prime different goals. While anxiety primes an implicit goal of uncertainty reduction, sadness primes an implicit goal of reward replacement. We offer that these motivational influences operate through an active process of feeling monitoring, whereby anxious or sad individuals think about the options and ask themselves, "What would I feel better about ellipsis?" Copyright 1999 Academic Press.

Journal Article↗
PubMed1997

Proton resonance imaging and relaxation in raw and cooked hen eggs.

In-vivo proton magnetic resonance imaging and relaxation time measurements were carried out on raw and cooked eggs. The relaxation time measurements revealed several interesting results. While there was very little change in the T1 values between the raw and cooked egg white, the T2 values followed the decreasing trend expected of water becoming bound. However, both the CH2 and CH3 moieties of the yolk lipids registered a statistically significant increase in their relaxation times. The T2 of the CH2 group, in particular, increased by 113% in the cooked egg. No striking changes, however, were observed between the proton images of the raw and cooked eggs.

Animals↗
PubMed1986

Ontogeny of neutrophil chemotaxis in fetal lambs.

Ontogeny of neutrophil chemotactic response using endotoxin activated adult sheep plasma as a source of complement derived chemotactic factor was examined in fetal lambs of gestational age 120-150 days. (Gestational period in sheep is approximately 150 days.) Neutrophils from fetal lambs of gestational age 120-130 days failed to respond to this chemotactic factor whereas neutrophils from fetal lambs above 131 days of gestational age responded at levels comparable to adult values. Examination of neutrophil chemotaxis in older fetuses using a different chemotactic factor derived from mitogen stimulated adult mononuclear cells revealed a selective failure of fetal neutrophils to respond to lymphocyte-derived chemotactic factor in the presence of a normal response to complement derived chemotactic factor. Among prematurely delivered twin fetuses alterations in comparison with the first twin or age-matched controls in peripheral neutrophil count (increase) and in chemotaxis (increase or decrease) were noted in second of twins delivered greater than or equal to 20 min after the first lamb, suggesting an extreme sensitivity of neutrophil functions to a variety of influences, similar to that seen in humans.

Animals↗
PubMed1985

Allogeneic leukocyte and germ cell-induced murine immunodeficiency.

Immune deficiency, as defined by significant decreases in lymphocyte Con A and allo-reactivity and in natural killer (NK) function, was induced in normal adult mice by i.p. injections of combinations of allogeneic testicular germ cells and splenic leukocytes over 3 wk. This immune deficiency was evident at 8 wk after initial injection, and profound by 12 wk. Neither leukocytes nor testicular cells, given alone, were able to induce similar immune deficiency. These findings suggest the possibility that allogeneic germ cells and leukocytes of semen, on repeated administration, may induce immune deficiency and may act as co-factors to viral agents in the development of clinical AIDS in humans.

Animals↗
PubMed1984

Ontogeny of the immune system: fetal lamb as a model.

We examined adult sheep lymphocytes for the following surface markers: Surface membrane immunoglobulin, antigen identified by anti-sheep thymocyte globulin and complement receptors. We quantitated sheep peripheral blood mononuclear leukocyte proliferative responses to mitogens and alloantigens, and demonstrated a neutrophil-directed chemotactic factor (N-LDCF) liberated by mitogen-stimulated sheep mononuclear cells. A comparison of adult and fetal sheep from 120-150 d of gestation demonstrated that 1) fetal sheep had adult proportions of surface membrane Ig+ and T+ lymphocytes but a significant decrease in FcIgG receptor+ lymphocytes, 2) proliferative responses of fetal sheep blood mononuclear cells to mitogens and alloantigens were comparable to adult responses, and 3) fetal mononuclear leukocytes failed to produce the lymphokine, N-LDCF, in response to mitogen stimulation.

Age Factors↗
PubMed1982

Phagocyte chemotaxis in the perinatal period.

Cross-sectional and limited sequential studies of neutrophil and monocyte chemotaxis were done using cells isolated from cord blood and peripheral blood of 2- to 6-day-old neonates and infants at 4 and 6 months of age. These studies show that cord blood phagocyte chemotaxis is comparable to adult values, whereas phagocyte chemotaxis at 2-6 days of age is significantly lower than adult (P less than 0.01) or cord (P less 0.01) chemotaxis values. At 6 months of age, phagocyte chemotaxis is still low compared to adult values (P less than 0.01).

Adult↗
PubMed1982

Isolation of ovine lymphocytes, granulocytes, and monocytes by counterflow centrifugation elutriation.

A simple, brief 1-step counterflow centrifugation elutriation technique is described for the recovery of highly purified populations of lymphocytes and granulocytes from adult and fetal ovine peripheral blood. Monocytes are obtained as an enriched population. Lymphocyte and granulocyte recoveries average 80%, higher than with routine gradient centrifugation procedures. In this described technique, inexpensive medium is used, and it is completed in about 90 minutes. The individual blood cellular populations, when tested appropriately, demonstrated normal functional responses.

Animals↗
PubMed1981

Phosphoenolpyruvate carboxykinase activity in human amniotic fluid.

Amniotic fluid samples obtained from normal pregnancies during gestation were used to quantitate the levels of phosphoenolpyruvate carboxykinase (PEPCK) activity. It is concluded that: (1) PEPCK activity was highest in the amniotic fluid cells of midtrimester pregnancies as compared to those of pregnancies close to term; (2) the activity of PEPCK seen in the amniotic fluid supernatant was about one fourth to one half of that seen in the amniotic cells; (3) the amniotic fluid supernatant PEPCK activity fluctuated very little during the entire gestation.

Amniotic Fluid↗
PubMed1981

Reduced concanavalin A capping of neonatal polymorphonuclear leukocytes (PMNs).

Neonatal polymorphonuclear leukocytes (PMNs) have previously been shown to be chemotactically deficient. To probe the mechanism(s) responsible for this deficiency, we have investigated the phenomenon of concanavalin A-induced capping in neonatal PMNs. PMNs from cord blood of 17 healthy, full-term infants and 17 normal adult volunteers were isolated by standard Ficoll-Hypaque and dextran sedimentation. After incubation with and without colchicine, the cells were reincubated with fluorescein isothiocyanate-Con A, fixed, and prepared in wet mounts. Using a fluorescence microscope, PMNs were identified, and percentage of the capped cells was counted. Upon treatment with colchicine, adult PMNs showed a significant increase in the percentage of capped cells. By contrast, the cord blood PMNs showed no significant increase in capping after colchicine treatment. The difference between percentage of PMNs showing colchicine-induced capping in adult and cord blood was highly significant (P less than 0.01; Student's t test).

Adult↗