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Biomedical subjects

A Ray

Publications and source records attributed to A Ray.

At least 91 records · Page 5Linked to original sources

Rhinovirus stimulation of interleukin-6 in vivo and in vitro. Evidence for nuclear factor kappa B-dependent transcriptional activation.

To further understand the biology of rhinovirus (RV), we determined whether IL-6 was produced during RV infections and characterized the mechanism by which RV stimulates lung cell IL-6 production. In contrast to normals and minimally symptomatic volunteers, IL-6 was detected in the nasal washings from patients who developed colds after RV challenge. RV14 and RV1A, major and minor receptor group RVs, respectively, were potent stimulators of IL-6 protein production in vitro. These effects were associated with significant increases in IL-6 mRNA accumulation and gene transcription. RV was also a potent stimulator of IL-6 promoter-driven luciferase activity. This stimulation was modestly decreased by mutation of the nuclear factor (NF)-IL-6 site and abrogated by mutation of the NF-kappa B site in this promoter. An NF-kappa B-DNA binding activity, mediated by p65, p50, and p52 NF-kappa B moieties, was rapidly induced in RV-infected cells. Activator protein 1-DNA binding was not similarly altered. These studies demonstrate that IL-6 is produced during symptomatic RV infections, that RVs are potent stimulators of IL-6 elaboration, and that RV stimulation IL-6 production is mediated by an NF-kappa B-dependent transcriptional stimulation pathway. IL-6 may play an important role in the pathogenesis of RV infection, and NF-kappa B activation is likely to be an important event in RV-induced pathologies.

Adult↗

A mutant of Pseudomonas aeruginosa that lacks c-type cytochromes has a functional cyanide-insensitive oxidase.

Using transposon mutagenesis and screening for the loss of the ability to oxidise the artificial electron donor N,N,N',N'-tetramethyl-p-phenylenediamine, we have isolated a mutant of Pseudomonas aeruginosa that lacks all c-type cytochromes. This mutant is unable to grow anaerobically with nitrate as a terminal electron acceptor. Analysis of its respiratory function indicates that the mutant has lost its cytochrome c oxidase-terminated respiratory pathway but the cyanide-insensitive oxidase-terminated branch remains functional. Complementation of the mutant by in vivo cloning led to recovery of the wild-type characteristics. These data are consistent with the idea that the cyanide-insensitive respiratory pathway does not contain haem c and that the pathway's terminal oxidase is a quinol oxidase.

Electron Transport Complex IV↗

Regulation of NFIL-6 and IL-6 expression by basic fibroblast growth factor in osteoblasts.

We determined whether basic fibroblast growth factor (bFGF) regulated the expression of IL-6 and NFIL-6 in osteoblasts. In mouse osteoblastic MC3T3-E1 cells, bFGF (10(-8) M) increased NFIL-6 mRNA 2-fold at 30 minutes and 3-fold at 2 h. IL-6 mRNA was increased by bFGF 10(-8) M after 1 h. IL-6 protein was detectable in control cultures but was significantly increased by bFGF (10(-8) M) at 4 h. Immunofluorescence analysis of MC3T3-E1 cells showed primarily cytoplasmic and perinuclear NFIL-6 staining in control cultures while bFGF-treated cells showed increased NFIL-6 staining at 2 and 4 h. Western blotting revealed that bFGF increased NFIL-6 protein at 2 h. In calvarial mouse osteoblasts, bFGF 10(-8) M induced IL-6 mRNA as early as 1 h and significantly increased IL-6 protein levels as early as 2 h. In conclusion, bFGF stimulates IL-6 and NFIL-6 mRNA in osteoblasts. The increase in NFIL-6 mRNA was associated with increased NFIL-6 protein. The increase in IL-6 mRNA was also associated with increased IL-6 protein. We propose that activations of NFIL-6 and IL-6 may be important mediators of the effects of bFGF on bone cells.

Animals↗

Critical cooling and warming rates to avoid ice crystallization in small pieces of mammalian organs permeated with cryoprotective agents.

Measurements were made by differential scanning calorimetry on small pieces of rabbit kidney permeated with 2, 3-butanediol containing mainly the levo- and dextro-isomers. The critical cooling rates necessary to vitrify the pieces of organ, and the corresponding critical warming rates which are required to avoid crystallization in the vitrified samples, were determined. The dynamic method used for these determinations is described. The glass-forming tendency and the stability of the amorphous state were both greater in the kidney tissue samples than in the bulk cryoprotective solution. This result is discussed in the context of the lowering of the freezing point of water in emulsions and the promotion of supercooling in hydrogels and porous materials. In corresponding experiments with rat hearts impregnated with 1,2-propanediol, only the critical warming rate was reduced.

Animals↗

Prevalence of serum antibodies to synthetic peptides to HPV16 epitopes among Indian women with cervical neoplasia.

Serum samples from 38 Indian women with cervical intraepithelial neoplasia (CIN) and cancer along with 20 control women were analysed for IgG antibodies against a panel of four synthetic peptides derived from early and late gene open reading frames of HPV16. The cervical tissue samples from these patients were also subjected to PCR in order to detect the presence of human papilloma viruses (HPVs) type 6, 11 and 16 DNA, using a set of primers for the E6 open reading frames in order to establish the acquisition of HPV infection. E2, E6 and L1 peptides of HPV16 were found to be highly reactive with the patients' sera, and a significant prevalence of antibodies to E6, E2 and L1 (P < 0.01) was observed among women with CIN, while antibodies to E6 peptide were only significantly elevated (P < 0.01) among women with cervical invasive carcinoma. Furthermore, there was good agreement between the development of the E6 antibody response and the presence of HPV16 E6 DNA among women with CIN and cervical invasive carcinoma as shown by high values of the kappa coefficient (0.7-1.0). The study clearly revealed a strong agreement between two assay methods defining unambiguous immunogenic B-cell epitopes on synthetic peptides to early and late gene open reading frames of HPV16 which could be used in HPV peptide serology. As such, single or combination of peptides in HPV peptide serology can be used as a screening tool to identify HPV-associated cervical lesions.

Amino Acid Sequence↗

SCATPLOT: a computer program for determination of binding parameters of non-linear non-cooperative ligand-substrate interactions.

The importance of computer-assisted analysis of a non-linear binding phenomenon through Scatchard equation has been widely acknowledged. While several user-friendly softwares [LIGAND, SCTFIT, ALLFIT] are available for determining the binding parameters of nonlinear Scatchard phenomenon, there is no easily available software covering the class of phenomena described by the McGhee and von Hippel formalism [J. Mol. Biol. 86, 469-489 (1974)]. We report here user-friendly software, SCATPLOT, developed in Turbo BASIC, for the numerical estimation of binding parameters of a non-cooperative ligand-substrate interaction doing best fit to the experimental data on the basis of McGhee and von Hippel equation for a nonlinear Scatchard plot. A new parameter has also been incorporated to guide the process of least square analysis and subsequent determination of binding parameters.

Algorithms↗

Enhancement of somatic intrachromosomal homologous recombination in Arabidopsis by the HO endonuclease.

The HO endonuclease promotes gene conversion between mating-type alleles in yeast by a DNA double-strand break at the site of conversion (the MAT-Y/Z site). As a first step toward understanding the molecular basis of homologous recombination in higher plants, we demonstrate that expression of HO in Arabidopsis enhances intrachromosomal recombination between inverted repeats of two defective beta-glucuronidase (gus) genes (GUS- test construct). One of these genes has the Y/Z site. The two genes share 2.5 kb of DNA sequence homology around the HO cut site. Somatic recombination between the two repeats was determined by using a histochemical assay of GUS activity. The frequency of Gus+ sectors in leaves of F1 plants from a cross between parents homozygous for the GUS- test construct and HO, respectively, was 10-fold higher than in F1 plants from a cross between the same plant containing the GUS- test construct and a wild-type parent. Polymerase chain reaction analysis showed restoration of the 5' end of the GUS gene in recombinant sectors. The induction of intrachromosomal gene conversion in Arabidopsis by HO reveals the general utility of site-specific DNA endonucleases in producing targeted homologous recombination in plant genomes.

Arabidopsis↗

A novel cis-acting element is essential for cytokine-mediated transcriptional induction of the serum amyloid A gene in nonhepatic cells.

Serum amyloid A (SAA) is a plasma protein which has been associated with several diseases, including amyloidosis, arthritis, and atherosclerosis, and its abnormal expression, particularly in nonhepatic cells, is implicated in the pathogenesis of these diseases. Transfection and DNA-binding studies were performed to investigate the mechanism controlling cytokine-induced, nonhepatic expression of the SAA gene. We have identified a novel promoter, located between positions -280 and 224, that confers interleukin-6 (IL-6) inducibility to an SAA-chloramphenicol acetyltransferase reporter gene in both nonhepatic and hepatic cells. DNase I protection assays revealed, within this region, three homologous highly pyrimidine rich octanucleotide sequence motifs, termed SAA-activating sequences (SAS). Specific mutations within these three SAS motifs severely reduced IL-6-mediated induction of the reporter gene in transfected nonhepatic cells but not in liver cells. A nuclear factor activated by IL-6 in both hepatic and nonhepatic cells efficiently interacts with the SAS. The induction kinetics and cycloheximide sensitivity of this SAS-binding factor (SAF) suggested that de novo synthesis of this factor itself or an activator protein is essential. Loss of DNA-binding ability as a result of in vitro dephosphorylation, induction of SAA-chloramphenicol acetyltransferase reporter gene activity in the presence of genistein, a protein kinase inhibitor, further indicate that a phosphorylation step is necessary for the activation of SAF. Our results suggest that SAF is a key regulator of cytokine-mediated SAA gene expression in some nonhepatic cells.

Animals↗

SHORT INTEGUMENT (SIN1), a gene required for ovule development in Arabidopsis, also controls flowering time.

The short integument (sin1) mutation causes a female-specific infertility, and a defect in the control of time to flowering in Arabidopsis. Female sterility of Sin- plants is due to abnormal ovule integument development and aberrant differentiation of the megagametophyte in a subset of ovules. An additional defect of sin1 mutants is the production of an increased number of vegetative leaf and inflorescence primordia leading to delayed flowering. The delayed flowering phenotype of sin1-1 is not due to a defect in the perception of day length periodicity or in gibberellic acid metabolism. Phenotypes of double mutant combinations of sin1 with terminalflower (tfl1) indicate that SIN1 activity is required for precocious floral induction typical in a tfl1 mutant. Unexpectedly, sin1-1 tfl1-1 plants do not make pollen, thus revealing a novel role for TFL1 in the anther. Early flowers of sin1-1 ap1-1 double mutants are transformed to long inflorescence-like shoots. A genetic model for the role of SIN1 in flowering time control is proposed.

Adaptor Protein Complex 1↗

[15 years survival of the Mac-Kee Farrar metal hip prosthesis. Apropos of 58 cases and 4 explanted cups].

PURPOSE OF THE STUDY: Despite a high percentage of loosening (femoral, iliac or both), many surgeons have been surprised by some excellents results of Mac Kee Farrar prosthesis after 15, or even 20 years follow-up. MATERIALS AND METHODS: 37 patients (on 58) were reviewed with a follow-up of more than 15 years (48 hips). Among 17 cases followed for more than 20 years, with very good results (clinical and radiological), only one femoral loosening was observed. A part, 4 paired explanted implants (loosening at 18 years for 3 and at 21 years for one) were examined for a dimensional and metallurgic study. RESULTS: The results showed: no wear, very good bearing surface statement and sphericity, We never observed agressive granulomatous lesions with metallic particles (metallosis), nor wear concerning the cup. CONCLUSION: The peripheric design appears able to give a very good pressure repartition from cup to bone, allowing a homogeneous coat of cement with an equal thickness, and avoids loosening. Finally, we think that the progressive polar cavity in the cup, could have a great importance on lubrification, as an hydrokinetic reserve and micropump for synovial fluid.

Adult↗

A comparative evaluation of immunotoxicity of DDT and its metabolites in rats.

Effects of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its metabolites, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethene (DDE), 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD) and 2,2-bis(p-chlorophenyl) acetic acid (DDA) were comparatively evaluated on humoral and cell mediated immune (CMI) responses in rats. Rats were given a diet containing 200 ppm of the various test compounds for 6 weeks and were subsequently immunized with ovalbumin. DDT, DDE and DDD, all induced differential degrees of humoral and cellular immune suppression. There were (a) increases in albumin/globulin ratios, (b) suppression of IgM and IgG levels, and (c) attenuations in ovalbumin induced antibody responses. In CMI studies, there were marked inhibitions of (a) leucocyte and macrophage migration factors, and (b) delayed type hypersensitivity (DTH) reaction. Whereas, these effects were most marked with DDE and DDD, DDA did not elicit such immunomodulatory effects. It is inferred that suppression of immune responses by immediate DDT metabolites, DDE (and DDD and not DDA) is an important determinant of the toxicity of DDT (DDE > DDD > DDT) and the influence of this environmental pollutant in health and disease.

Animals↗

Bioenergetic effects of repeated +Gz acceleration on rat heart: a 31P-NMR study on isolated hearts.

This investigation was designed to determine whether repeated exposure to high sustained +Gz acceleration induces persisting changes in the myocardial energetic metabolism. Rats were exposed to three plateaus of 30 s at 10 +Gz, four times a week, for 4 weeks. Myocardial concentrations of high-energy phosphorylated compounds were evaluated by 31P-nuclear magnetic resonance (NMR) spectroscopy on isolated hearts submitted to isovolumic aortic perfusion. Heart performances were recorded using the intraventricular balloon method. Compared to the hearts of control rats (n = 5), the hearts of centrifuged rats (n = 5) had higher concentrations of inorganic phosphate (Pi:1.40 +/- 0.33 nM vs. 0.36 +/- 0.07 mM; p < 0.01), decreased phosphocreatine concentrations (PC:15 +/- 0.39 mM vs. 15.69 +/- 0.19 mM; p < 0.01), and a lower left ventricular developed pressure (LVDP) (21 +/- 1 mmHg vs. 34 +/- 2 mmHg; p < 0.01). The workload was increased by sequential augmentation of calcium in the perfusion medium. The relationship between LVDP and the Pi/PC ratio showed that the cost of the cardiac work was greater for the centrifuged rats.

Animals↗

Difficulties in obstetric practice in a hill subdivision.

The present study includes 2249 cases of delivery over a period of 4 years. Difficulties faced, complications and their management were highlighted. Teen-age pregnancy was 14.98% while 52.33% cases were in the age group of 20-25 years. A total of 26.30% cases were booked. There were 53.66% primigravida cases, 43.88% cases from gravida II to gravida IV and 2.44% were grande multipara. Noted complications were pre-eclampsia 7.4%, eclampsia 0.4% and pulmonary tuberculosis 3.7%. All the patients were anaemic. Severe anaemia was noted in 3% cases, moderate in 21% cases and mild in 76% cases. Abortion cases both spontaneous and induced or criminal were 17.02%. While considering the total number of pregnancy cases, caesarean section was performed in 4.22%. Male babies were 51.30% whereas 48.68% were females. Majority (41.48%) of the babies weighed between 2.1 and 2.5 kg range. Fresh and macerated stillbirths were 7.4%.

Adolescent↗

Effects of some psychotropic agents on cognitive functions in rats.

The effects of some psychotropic agents were evaluated on cognitive function in rats. Acute administration of antipsychotic agents chlorpromazine, haloperidol or pimozide-all inhibited the active avoidance response as elicited by pole climbing test-the least effect being seen with pimozide. The antianxiety benzodiazepines, lorazepam and alprazolam, also attenuated active avoidance learning with the latter showing lesser effects. Maze task performance was differentially affected by these psychotropic drugs with maze traversing time being increased significantly after all drug treatment, except alprazolam.

Animals↗

Immunotoxicity of pesticides: perspectives and trends.

In recent years, great concern has been expressed about genotoxic potential of pesticide chemicals. These toxic chemicals have become an integral part of the ecosystem and the human health effects of these agents are yet to be satisfactorily defined. The objectives of this review is to examine the sources of information available; evaluation of experimental protocols employed for assessment of immunological effects; and to study specific cellular and molecular locus which could be responsible for impaired immune responsiveness. It is emphasized that threshold level for the pesticide effect below which no effect would be seen, depends on the animal species, the method of testing for immune responses and type of antigen used. A comparative assessment of immune responses using different antigens is, therefore, an important aspect of pesticide immunotoxicity. In view of widespread use, distribution and stability of some of these compounds in the environment, pesticide exposure may play a greater role in suspected fragile immune system, and may result in altered disease susceptibility. An understanding of these risks depends, to a great extent, upon cellular and molecular events underlying pesticide-induced immune alterations in experimental animals. It is, therefore, proposed that pesticide chemicals may influence humoral immunity while having no detectable effect on cell-mediated immunity (CMI); immune dysfunction is related to dose and duration of pesticide exposure; a single assay of immune function may not be appropriate to detect pesticide-induced immune dysfunction; since many immune responses are genetically controlled, alterations in responsiveness to one challenge in a given animal model may not hold true in second one; although it has been established that pesticide chemicals can alter immune function, the mechanisms of action have yet to be determined. This paper also reviews the effects of pesticide on lymphocyte function and suggests that lymphocyte dysfunction may be an integral part of pesticide-induced immunosuppression and presents an approach which may serve to delineate the possible mechanisms of action. It is quite clear that pesticide-induced immunomodulation endangers humans and animals. This hazard should, therefore, not to be underestimated in evaluation of toxicity of these chemicals. However, additional research is needed in basic mechanism of immunotoxicity and identification of susceptibility factors which predispose to these reactions.

Animals↗

Modulation of humoral and cell-mediated immune responses by Azadirachta indica (Neem) in mice.

The effects of A. indica (AI, Neem) were evaluated on tests of humoral and cell-mediated immune responses after 3 weeks of oral AI (leaf extract) treatment in ovalbumin immunized mice. At the dose levels tested, AI (10, 30 or 100 mg/kg), had no appreciable influence on different organ (liver, spleen, thymus)/body weight indices, when compared to controls. In tests for humoral immune responses, AI (100 mg/kg) treated mice had higher (1) IgM and IgG levels, and (b) anti-ovalbumin antibody titres, when compared to the vehicle treated group. In tests for cell-mediated immune responses, there was an enhancement (%) of (a) macrophage migration inhibition, and (b) footpad thickness after AI (100 mg/kg) treatment. These results are discussed in light of the possible immunopotentiating effects of AI.

Administration, Oral↗

Influence of subchronic exposure to lindane on humoral immunity in mice.

Lindane suppressed both primary and secondary antibody responses to sheep red blood cell (SRBC) in albino mice, the effects being more pronounced on the secondary than the primary response. However, a longer duration of pesticide exposure induced similar degrees of immunosuppression on both responses. The sequential study of plaque forming cells (PFC) kinetics revealed that suppression of plaque formation not only occurred at peak days but also on pre and post peak days, and there was no delay in peak antibody formation. Moreover, reduction in the primary PFC was not associated with decrease in the antibody response to SRBC. The results indicate that lindane suppresses both primary and secondary humoral immune responses in a time and dose dependent manner, and suggest a threshold susceptibility to exposure.

Animals↗