Biomedical subjects

C Wood

Publications and source records attributed to C Wood.

At least 109 records · Page 6Linked to original sources

PubMed1998

Cytomegalovirus and human herpesvirus-6 trans-activate the HIV-1 long terminal repeat via multiple response regions in human fetal astrocytes.

Cytomegalovirus (CMV) and human herpesvirus-6 (HHV-6) infection stimulated HIV-1 replication and trans-activated the HIV-1 promoter (the long terminal repeat or LTR) to a similar extent in transfected, nonimmortalized, human fetal astrocytes. CMV infection increased basal LTR expression by approximately sevenfold, while HHV-6 infection increased basal LTR expression by fourfold. This enhancing effect required cell-cell contact between CMV-infected or HHV-6-infected and LTR-containing cells. To determine the target regions on the HIV promoter that respond to CMV and HHV-6 trans-activation, several modified LTR-reporter gene constructs were tested. Loss of functional NFkappaB, Sp1, or upstream modulatory sites on the LTR caused significant reduction ofbasal LTR expression in astrocytes. These elements also mediated the trans-activation events during HHV-6 or CMV infection in astrocytes, though to varying degrees. Electrophoretic mobility shift assays (EMSA) indicated that core, enhancer, and upstream modulatory regions of the LTR interacted specifically with nuclear proteins from both uninfected and CMV- or HHV-6-infected human fetal astrocytes. CMV or HHV-6 infection did not appear to induce unique, LTR-specific nuclear binding proteins, but rather enhanced the relative proportion of some of the existing protein complexes, in particular, the complexes formed with the AP-1 binding sites on the HIV-1 LTR (nt - 354 to - 316). Our data suggest that CMV or HHV-6 trans-activation of HIV LTR activity in human fetal astrocytes proceeds via intracellular molecular interactions involving herpesviral gene products, cellular proteins, and multiple sites on the LTR upstream of the TATA box. The pattern of LTR activity in astrocytes suggests that host cell factors modulating HIV expression may differ from those dominant in T-cells or immortalized astroglia, and this could contribute to differences in the astrocyte's ability to support HIV replication.

Astrocytes↗

PubMed1997

Detection of proviral DNA of bovine immunodeficiency virus in bovine tissues by polymerase chain reaction (PCR) and PCR in situ hybridization.

In this study, experiments were designed to investigate the distribution of bovine immunodeficiency virus (BIV) proviral DNA in the tissues and cells of infected calves by solution-phase polymerase chain reaction (SP-PCR) and PCR in situ hybridization (PCR-ISH). Total DNA samples extracted from tissues of 10 BIV-infected and 5 uninfected calves were amplified by SP-PCR with the primers directed to the BIV conserved pol gene segment. The identity of the SP-PCR product was confirmed by Southern hybridization with a BIV pol gene cDNA probe. SP-PCR results demonstrated that BIV proviral DNA was present predominantly in neural tissues and some lymphoid tissues in BIV-infected calves. It also was detected frequently in other tissues including lung, heart, esophagus, and pancreas. Further investigation on cell location of BIV proviral DNA was performed by in situ amplification of DNA on formalin-fixed tissue sections. The amplified DNA was subjected to in situ hybridization with an internal biotinylated probe and detected with streptavidin-gold followed by silver enhancement. Specific BIV proviral DNA signals were observed in neurons, microglial cells, lymphocytes, septal macrophages, smooth muscle cells, and endothelial cells. On the basis of these results, we conclude that BIV replicates in a variety of bovine tissues in vivo and has a broad cell tropism.

Animals↗

PubMed1997

p110delta, a novel phosphatidylinositol 3-kinase catalytic subunit that associates with p85 and is expressed predominantly in leukocytes.

We have identified a novel p110 isoform of phosphatidylinositol 3-kinase from human leukocytes that we have termed p110delta. In addition, we have independently isolated p110delta from a mouse embryo library on the basis of its ability to interact with Ha-RasV12 in the yeast two-hybrid system. This unique isoform contains all of the conserved structural features characteristic of the p110 family. Recombinant p110delta phosphorylates phosphatidylinositol and coimmunoprecipitates with p85. However, in contrast to previously described p110 subunits, p110delta is expressed in a tissue-restricted fashion; it is expressed at high levels in lymphocytes and lymphoid tissues and may therefore play a role in phosphatidylinositol 3-kinase-mediated signaling in the immune system.

Amino Acid Sequence↗

PubMed1997

Activation of HHV-8 by HIV-1 tat.

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Cell Line↗

PubMed1997

Efficiency of the OVATEC unit for estrus detection and calf sex control in beef cows.

Seventy five spring calving Gelbvieh and Angus cows were utilized over a three year period to evaluate the usefulness of the OVATEC intravaginal probe for indicating the onset of estrus and providing the possibility to influence the sex of the offspring by choosing a breeding time in relation to critical changes in cervical mucus conductivity. Cows were randomly assigned by breed each year into one of four treatments: (1) probed and inseminated when impedance values declined, creating conditions expected to favor X-bearing sperm and with it an increase in the conception of females (PF); (2) probed and inseminated when impedance values were rebounding, expected to favor Y-bearing sperms and with it an increase in the conception of males (PB); (3) standing estrus (AI); or (4) natural service by bull (NS). Cows grazed or were fed hay from tall fescue-legume pastures. Lutalyse was used to synchronize estrus in a two injection scheme. Vaginal probe readings were taken at first injection, second injection and every 12 h thereafter for 6 days. Visual observations for estrus were obtained for PF, PB and AI every 12 h postsecond injection. Rectal palpations of ovaries were obtained at standing heat in all but NS treatments. In cycling cows, probe readings increased prediction of estrus onset (P < 0.10) compared to visual observations and were similar (P > 0.95) to rectal palpations in all probed cows. PF cows delivered heifer calves at greater rates (P < 0.025) than all other treatments whereas PB cows delivered bulls at greater rates (P < 0.05) than all other treatments. Heifer to bull ratios were not different (P > 0.95) for AI or NS treatments. The results of this study indicate that the potential exists for increasing female offspring conceptions utilizing cervical mucus conductivity as a gauge for insemination times.

Administration, Intravaginal↗

PubMed1997

Immunogenicity of DNA damaged by reactive oxygen species--implications for anti-DNA antibodies in lupus.

Reactive oxygen species (ROS) are implicated in the inflammatory, autoimmune, connective tissue disease, systemic lupus erythematosus (SLE), particularly in respect of processes leading to the formation of pathological anti-DNA antibodies. Exposure to ROS increases the antigenicity of DNA for SLE antibodies, but data on the immunogenicity of ROS-DNA are not conclusive. In this study, we have examined the immunogenicity in rabbits, of DNA modified by three hydroxyl radical generating systems. Additionally, we investigated the antigenicity of UVA, UVB, and UVC irradiated DNA for lupus anti-DNA antibodies. Modification of DNA by both ROS and far UV dramatically increased its immunogenicity; the Fe2+ and H2O2 system resulted in antibodies that recognized both native and modified DNA. In our ELISA system, none of the UV antigens showed any antigenicity above native DNA for SLE sera. The data suggested that different profiles of antigenicity and immunogenicity arise dependent on the method of ROS production, but also that ROS-DNA may be a factor in antigen-driven immune complex formation in SLE.

Adult↗

PubMed1997

[Value and limits of selective bronchial obstruction in neonatal unilateral interstitial emphysema].

BACKGROUND: Two methods of selective ventilation have been used for treating severe localized pulmonary emphysema in the neonates: controlateral selective intubation and selective bronchial obstruction. CASE REPORTS: Three neonates with acute respiratory distress required respiratory support that was complicated by development of severe localized pulmonary interstitial emphysema of the right lobe (two cases) and the middle lobe (one case). Selective bronchial obstruction with a Swann Ganz catheter SF was tentatively made: in one case, improvement was moderate and transitory, requiring middle lobectomy. The localized emphysema disappeared within 3 days in the two other cases but a localized emphysema appeared in the controlateral lung in one of them, requiring left inferior lobectomy because the ineffectiveness of selective intubation or selective obstruction. CONCLUSION: Selective bronchial obstruction may fail but this easy and well tolerated method should be tried in severe localized emphysema, specially in those patients who cannot be ventilated with high-frequency oscillation.

Bronchi↗

PubMed1997

Laparoscopic hysterectomy.

The terminology of laparoscopically-assisted hysterectomies needs to be simplified and clarified. Laparoscopic hysterectomy should be used as a general term, whereas operative laparoscopy before hysterectomy, laparovaginal, laparoscopic total and subtotal hysterectomy should be used to describe the types of laparoscopic hysterectomy. The complication rates from laparoscopic hysterectomy, abdominal hysterectomy and vaginal hysterectomy are similar. The lower febrile morbidity after laparoscopic hysterectomy may be due to improved pelvic visualization compared to vaginal and abdominal hysterectomy. Controlled trials show that laparoscopic hysterectomy has advantages over abdominal hysterectomy which include reduced pain, reduced hospitalization time and earlier return to work. Most abdominal hysterectomies can be replaced by laparoscopic or vaginal hysterectomies. Whether this happens will depend upon adequate training facilities.

Controlled Clinical Trials as Topic↗

PubMed1997

Molecular modelling of the nicotinic acetylcholine receptor transmembrane region in the open state.

A model of the nicotinic acetylcholine receptor transmembrane region has been constructed which may represent the channel in its open-state. The positions of helices flanking the ion channel match those observed by electron microscopy and previously reported by others. Residues labelled, mutated or by other means known to have a strong influence on ion flux are each accessible from the lumen of the modelled channel. The model provides new insights into our current understanding of the ion channel structure, and suggests some novel explanations for the results of labelling and mutation studies such as those involving ion channel blockers and residue-dependent changes in ion selectivity.

Amino Acid Sequence↗

PubMed1997

Attention-deficit hyperactivity disorder: a category or a continuum? Genetic analysis of a large-scale twin study.

OBJECTIVE: To investigate heritability and continuum versus categorical approaches to attention-deficit hyperactivity disorder (ADHD), using a large-scale twin sample. METHOD: A cohort of 1,938 families with twins and siblings aged 4 to 12 years, recruited from the Australian National Health and Medical Research Council Twin Registry, was assessed for ADHD using a DSM-III-R-based maternal rating scale. Probandwise concordance rates and correlations in monozygotic and dizygotic twins and siblings were calculated, and heritability was examined using the De Fries and Fulker regression technique. RESULTS: There was a narrow (additive) heritability of 0.75 to 0.91 which was robust across familial relationships (twin, sibling, and twin-sibling) and across definitions of ADHD as part of a continuum or as a disorder with various symptom cutoffs. There was no evidence for nonadditive genetic variation or for shared family environmental effects. CONCLUSIONS: These findings suggest that ADHD is best viewed as the extreme of a behavior that varies genetically throughout the entire population rather than as a disorder with discrete determinants. This has implications for the classification of ADHD and for the identification of genes for this behavior, as well as implications for diagnosis and treatment.

Attention Deficit Disorder with Hyperactivity↗

PubMed1997

Psychological distress among female sex workers.

The prevalence and correlates of psychological distress were examined in a sample of 171 female sex workers in Queensland. It was found that 28 per cent were above the GHQ-28 threshold for mild psychiatric morbidity, a rate that is not appreciably different from that of women in the general community. The sample included only eight street sex workers, all of whom reported significant distress. Logistic regression analyses showed that a history of injecting drug use, an early age at leaving home and wanting to leave the sex industry were independent predictors of poor mental health. Distressed sex workers reported fewer sexual health examinations and less consistent condom use with their clients than those who were not distressed.

Adult↗

PubMed1997

Bleeding associated with vaginal hysterectomy.

The increased use of blood transfusion, ultrasound evidence of postsurgical haematoma, the frequency of postoperative febrile morbidity of unknown cause and reports of these complications in large series which contain both abdominal and vaginal hysterectomy over the last 25 years, suggests that bleeding may be more common after vaginal hysterectomy. We performed laparoscopy routinely after vaginal hysterectomy in 50 patients. The frequency of bleeding was 48%, consistent with other studies ranging from 30 to 98%. Arterial bleeding from a branch of the uterine or vaginal artery occurred in 20%. The frequency of bleeding was not related to uterine size, ranging from normal to that equivalent in size to that of a pregnancy of 18 weeks' gestation. The most common site of bleeding was the vaginal vault. Liberal definitions of haemorrhage, possible emphasis in speed in performing hysterectomy, and difficulty in visualizing and ligating major and minor blood vessels, may have contributed to the increased frequency of bleeding reported after vaginal hysterectomy. Haemostasis is more easily obtained at laparoscopic surgery because of magnification, close inspection, routine use of suction irrigation and bipolar electrocoagulation. Routine laparoscopy at the completion of vaginal hysterectomy is recommended. New and improved methods of vessel closure are also required. Attitudes to haemorrhage during hysterectomy require change to further reduce the use of blood transfusion.

Blood Loss, Surgical↗

PubMed1997

Immune suppression in calves with bovine immunodeficiency virus.

The present study was designed to evaluate the effect of bovine immunodeficiency virus (BIV) infection on immune functions and possible interactions between BIV and other bovine viruses in calves. Ten calves were inoculated intravenously with BIV, and five served as controls. An increased lymphocyte proliferation to BIV gag protein was demonstrated 2 to 6 weeks after BIV inoculation (P < 0.05). Lymphocyte subset differentiation revealed a decreased CD4/CD8 ratio (P < 0.05) during weeks 2 to 7, suggesting a possible immune dysfunction in BIV-infected calves. When the calves were inoculated with bovine herpesvirus type 1 (BHV-1), the antibody response to BHV-1 in BIV-infected calves was delayed and the antibody titers were significantly lower (P < 0.05). Injection of bovine viral diarrhea virus vaccine also elicited a lower neutralizing antibody response in BIV-infected calves. The results indicated that immune suppression occurred in BIV-infected calves.

Animals↗

PubMed1997

Transcriptional patterns of the pCD41 (U27) locus of human herpesvirus 6.

Human herpesvirus 6 (HHV-6) is a lymphotropic herpesvirus, and in vitro, it can productively infect many of the same cell types that human immunodeficiency virus (HIV) infects. Simultaneous infection of T cells by HIV and HHV-6 can lead to both activation of the HIV promoter and acceleration of the cytopathic effects. Several HHV-6 genes have been demonstrated to activate HIV promoter expression. Among them is a cDNA clone, pCD41 (U27), which codes for the HHV-6 DNA polymerase accessory protein. We have now further characterized the transcription pattern in the pCD41 locus and identified at least six RNA species, ranging in size from 1.2 to 4.5 kb. Northern (RNA) blot analyses showed no significant difference in RNA patterns between the HHV-6 variant A (GS) and variant B (Z29) viruses. All the RNA species detected by pCD41 are polyadenylated and polyribosome associated, suggesting that they may be actively engaged in protein synthesis. Cycloheximide and phosphonoacetic acid inhibition assay results indicate that all the pCD41 RNA species belong to the herpesviral early-late family. Using primer extension and S1 mapping techniques, the 5' and 3' ends of each transcript were mapped to different positions, and no splicing was observed.

Chromosome Mapping↗

PubMed1997

Detection of bovine immunodeficiency virus antibodies in cattle by western blot assay with recombinant gag protein.

A western blot assay using purified recombinant bovine immunodeficiency virus gag protein has been developed for detection of bovine immunodeficiency virus antibodies in bovine serum samples. The test was standardized with known bovine immunodeficiency virus positive and negative bovine serum samples and the monoclonal antibody to gag protein. Both naturally and experimentally infected cattle sera demonstrated positive test results. The result of western blot assay was compared with polymerase chain reaction test results in 134 blood samples collected from Kansas. Twenty-six samples tested positive for bovine immunodeficiency virus DNA with polymerase chain reaction (18.7%) and 25 were positive for the antibody to gag protein by western blot analysis (17.9%). Of 26 cattle testing positive using the polymerase chain reaction assay, 24 were antibody-positive by western blot assay, thus establishing a strong correlation between the two tests. The sensitivity and specificity of western blot relative to polymerase chain reaction are 0.92 and 0.99, respectively. The western blot assay proved to be a specific and sensitive test.

Animals↗

PubMed1997

Extracellular carbonic anhydrase and an acid-base disequilibrium in the blood of the dogfish Squalus acanthias

The electrometric [Delta]pH method and an in vitro radioisotopic HCO3- dehydration assay were used to demonstrate the presence of true extracellular carbonic anhydrase (CA) activity in the blood of the Pacific spiny dogfish Squalus acanthias. An extracorporeal circulation and stopflow technique were then used to characterise the acidbase disequilibrium in the arterial (postbranchial) blood. During the stopflow period, arterial pH (pHa) decreased by 0.028±0.003 units (mean ± s.e.m., N=27), in contrast to the increase in pHa of 0.029±0.006 units (mean ± s.e.m., N=6) observed in seawater-acclimated rainbow trout Oncorhynchus mykiss under similar conditions. The negative disequilibrium in dogfish blood was abolished by the addition of bovine CA to the circulation, while inhibition by benzolamide of extracellular and gill membrane-bound CA activities reversed the direction of the acidbase disequilibrium such that pHa increased by 0.059±0.016 units (mean ± s.e.m., N=6) during the stopflow period. When the CA activity of red blood cells (rbcs) was additionally inhibited using acetazolamide, the magnitude of the negative disequilibrium was increased significantly to -0.045±0.007 units (mean ± s.e.m., N=6). Blockage of the rbc Cl-/HCO3- exchanger using 4,4'-diisothiocyanostilbene-2,2'-disulphonic acid (DIDS) also increased the magnitude of the negative disequilibrium, in this case to -0.089±0.008 units (mean ± s.e.m., N=6). Exposure of dogfish to hypercapnia had no effect on the disequilibrium, whereas the disequilibrium was significantly larger under hypoxic conditions, at -0.049±0.008 units (mean ± s.e.m., N=6). The results are interpreted within a framework in which the absence of a positive CO2 excretion disequilibrium in the arterial blood of the spiny dogfish is attributed to the membrane-bound and extracellular CA activities. The negative disequilibrium may arise from the continuation of Cl-/HCO3- exchange in the postbranchial blood and/or the hydration of CO2 added to the plasma postbranchially. Two possible sources of this CO2 are discussed; rbc CO2 production or the admixture of blood having 'low' and 'high' CO2 tensions, i.e. the mixing of postbranchial blood with blood which has bypassed the respiratory exchange surface.

Journal Article↗

PubMed1997

The interactive effects of feeding and exercise on oxygen consumption, swimming performance and protein usage in juvenile rainbow trout (Oncorhynchus mykiss)

The impacts of feeding on the rate of O2 consumption (O2), aerobic swimming performance, nitrogenous waste excretion (ammonia-N and urea-N) and protein utilization as an aerobic fuel were investigated in juvenile rainbow trout. Feeding trout to satiation (in groups of 120) resulted in rapid growth and elevated routine O2 by 68% relative to fasted fish and by 30% relative to trout fed a maintenance ration of 1% of body mass daily. This in-tank O2 of satiation-fed trout was approximately 70% of the O2max observed at the critical swimming speed (UCrit) when trials were performed on individual trout in swimming respirometers. Feeding increased O2 at all swimming speeds; the absolute elevation (specific dynamic action or SDA effect) was dependent on ration but independent of swimming velocity. There was no difference in O2max at UCrit amongst different ration treatments, but UCrit was significantly reduced by 15% in satiation-fed fish relative to fasted fish. These results suggest that the irreducible SDA load reduces swimming performance and that O2max is limited by the capacity to take up O2 at the gills and/or to deliver O2 through the circulatory system rather than by the capacity to consume O2 at the tissues. Ammonia-N and urea-N excretion increased with protein intake, resulting in a 6.5-fold elevation in absolute protein use and a fourfold elevation in percentage use of protein as an aerobic fuel for routine metabolism in satiation-fed trout (50-70%) relative to fasted fish (15%). Urea-N excretion increased greatly with swimming speed in all treatments, but remained a minor component of overall nitrogen excretion. However, even in satiation-fed fish, ammonia-N excretion remained constant as swimming speed increased, and protein did not become more important as a fuel source during exercise. These results suggest that the reliance on protein as a fuel is greatly dependent on feeding quantity (protein intake) and that protein is not a primary fuel for exercise as suggested by some previous studies.

Journal Article↗

PubMed1997

Pulsatile urea excretion in the toadfish (Opsanus beta) is due to a pulsatile excretion mechanism, not a pulsatile production mechanism

When subjected to a crowding/confinement protocol in the laboratory, toadfish become facultatively ureotelic, excreting approximately 90 % of their nitrogenous waste as urea-nitrogen (urea-N). The great majority of this excretion occurs via large, irregular pulses from the head region which occur on average once per day, with a duration of 3 h or less. Pulses measured chemically by the appearance of urea-N in the external water were identical to those measured by assaying [14C]urea appearance in the water from the blood plasma. Individual toadfish maintained plasma urea concentrations over widely differing ranges (660039 890 µmol-N l-1). However, independent of absolute levels, both [14C]urea and total urea were distributed at ratios close to unity between the blood plasma and the water compartments of liver and white muscle. At times of pulsatile excretion, plasma urea concentration fell sharply. These decreases, distributed throughout the tissues of the whole body, closely matched the sizes of the measured excretion pulses. Between pulses, plasma urea concentration increased steadily at a much slower rate; the rate of rise, when distributed throughout the tissues of the whole body, corresponded to the time-averaged excretion rate over the whole day. Infusion of a typical pulse amount of urea immediately after the end of a natural pulse event raised plasma urea concentration slightly above the pre-pulse level, but did not induce another pulse event. Plasma cortisol levels declined by approximately 60 % over the 4 h period prior to a natural pulse event and then rose quickly again once the pulse had occurred. These results indicate that urea pulses are due to activation of an excretion mechanism that rapidly clears urea from the blood plasma, thereby lowering stores throughout the whole body. Metabolic production of urea is continuous and is not responsible for pulsatile excretion. The pulse event is not triggered by a specific plasma urea threshold, but may involve the hypothalamointerrenal axis.

Journal Article↗