PubMed Health⌕ Search

Biomedical subjects

D Moyes

Publications and source records attributed to D Moyes.

At least 19 recordsLinked to original sources
PubMed2002

[Fiber-optic bronchoscopic biopsy of bronchial smooth muscle. Efficacy of the technique in individuals with normal lung function and patients with COPD].

BACKGROUND AND OBJECTIVES: The epithelium and airway smooth muscles of patients with chronic obstructive pulmonary disease (COPD) or bronchial asthma undergo certain structural changes that are probably related to increased expression of inflammatory molecules and cell growth factors. Studying the relation between disease and changes in bronchial smooth muscle is difficult if investigation is restricted to samples from autopsies or thoracotomies. This study was designed to evaluate the probability of obtaining bronchial smooth muscle by endoscopic bronchial biopsy in patients with COPD and from individuals with normal lung function, the relation of disease to bronchial epithelial histology, and the potential usefulness of studying airway muscle remodeling events. METHODS: Forty-two patients undergoing diagnostic fiberoptic bronchoscopy were enrolled. Bronchial biopsies were taken systematically from the lobar and segmental dividing ridges. The epithelial structure was analyzed by conventional histology. The smooth muscle was identified by immunohistochemistry (anti-desmin antibody assay) and Western-blot analysis (anti-desmin, actin and myosin antibodies). RESULTS: Sixty-nine percent of the biopsies contained bronchial smooth muscle. The probability of obtaining smooth muscle was higher in segmental than in lobar biopsies (72 vs 30%, p < 0.05). This probability was unrelated to the presence of COPD or to signs of epithelial inflammation. The fragments allowed us to use electrophoresis to identify protein structures (myosin, actin, desmin) involved in muscle remodeling processes. CONCLUSIONS: Endoscopic biopsy of the bronchi allows us to obtain bronchial smooth muscle samples in a large percentage of patients, particularly when performed on segmental bronchi. The technique may be useful for future studies examining the processes of airway smooth muscle remodeling.

Aged↗
PubMed2000

An epithelial cell line that can stimulate alloproliferation of resting CD4+ T cells, but not after IFN-gamma stimulation.

It has previously been shown that IFN-gamma-induced up-regulation of HLA class II on the surface of epithelial cells is not sufficient to induce proliferation of allospecific CD4+ T cells in vitro. To further investigate this phenomenon, a human epithelial bladder carcinoma, T24, was induced to constitutively express HLA class II without IFN-gamma stimulation, by permanent transfection with the full-length class II transactivator (CIITA) gene. Proliferation of allospecific T cells to transfected and wild-type cells with and without prior activation with saturating levels of IFN-gamma for 4 days was examined. IFN-gamma-activated T24 did not induce any response from CD4+ T cells. However, T24.CIITA induced significant levels of alloproliferation, which could be abrogated by pretreatment of T24.CIITA with a mAb to LFA-3. Prestimulation of T24. CIITA with saturating levels of IFN-gamma for 4 days also prevented allospecific CD4+ T cell proliferation. These findings suggest that epithelial cells may be intrinsically able to process and present alloantigen and provide adequate costimulation. We propose that IFN-gamma has a secondary, as yet unidentified, effect that acts to negatively regulate this response, at least in some epithelial cells.

CD4-Positive T-Lymphocytes↗
PubMed2000

Contact activation in shock caused by invasive group A Streptococcus pyogenes.

OBJECTIVES: The aim of this study was to characterize abnormalities of coagulation in mice with experimental, invasive group A, streptococcal shock, in an attempt to explain the prolongation of the activated partial thromboplastin time identified in patients with streptococcal toxic shock syndrome. DESIGN: A longitudinal descriptive animal model study of coagulation times and single coagulation factors in mice infected with Streptococcus pyogenes. This was followed by an experimental study to determine whether streptococci or streptococcal products could activate the human contact system in vitro. SETTING: University infectious diseases and hemostasis molecular biology laboratories. SUBJECTS: CD1 outbred mice. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Coagulation times, single factor assays, and bradykinin assays were conducted on murine plasma at different times after streptococcal infection and compared with uninfected mice. In experiments in which streptococcal products were co-incubated with human plasma, we compared coagulation times, single factor assays, and activities against a range of chromogenic substrates with control plasma. In a murine model of streptococcal necrotizing fasciitis, the activated partial thromboplastin times were significantly prolonged in infected mice compared with controls, whereas prothrombin times were normal, suggesting an isolated abnormality of the intrinsic pathway. Bleeding was not seen. Prolongation of activated partial thromboplastin time was associated with reduced factor XII and prekallikrein, whereas levels of factors VIII, IX, XI, and high molecular weight kininogen were elevated. In vitro studies suggested that streptococcal supernatants can activate prekallikrein, in addition to causing plasminogen activation through the action of streptokinase. CONCLUSIONS: Prolongation of activated partial thromboplastin time in streptococcal toxic shock syndrome is associated with activation of the contact system, possibly contributing to the profound shock associated with streptococcal toxic shock syndrome.

Animals↗
PubMed1999

Core temperature changes during open and laparoscopic colorectal surgery.

BACKGROUND: Perioperative hypothermia increases the morbidity of surgery. However, the true incidence of hypothermia during prolonged laparoscopic surgery is still unknown. To investigate this issue, we compared the temperature change between patients undergoing open and laparoscopic colorectal surgery. METHODS: Sixty consecutive patients who were undergoing laparoscopic (33) or open (27) colorectal surgery had a transesophageal temperature probe placed after induction of anesthesia. Core temperature values were measured at 15-min intervals. RESULTS: The groups were not statistically different with respect to age, sex, body surface area, or initial transesophageal temperature. The type of surgical access (open or laparoscopic) caused no difference in the incidence of hypothermia. The use of a forced-air warming device produced significantly less hypothermia during laparoscopic surgery. Men showed significantly less variability in temperature change than women. CONCLUSIONS: The incidence of hypothermia in open and laparoscopic colorectal surgery is similar. Forced-air warming devices are of value in prolonged laparoscopic surgery. A gender difference in the response to a hypothermic situation has not been previously reported. This finding warrants further investigation.

Adult↗
PubMed1997

The role of nitric oxide in experimental murine sepsis due to pyrogenic exotoxin A-producing Streptococcus pyogenes.

Nitric oxide (NO) produced by inducible NO synthase (iNOS) mediates hypotension in endotoxemia. In this study, NO induction by a toxin-producing Streptococcus pyogenes isolate, H250, and by recombinant streptococcal pyrogenic exotoxin A (rSPEA) has been examined, both in vitro and in vivo. Streptococcal supernatants, but not rSPEA, induce production of nitrite by murine macrophages when both are coincubated with gamma interferon. Intraperitoneal injection of rSPEA did not cause significant production of NO. However, an elevated level of nitrate in serum was detected in a model of streptococcal fasciitis due to live H250. iNOS was localized to Kupffer cells, hepatocytes, and renal tubular cells by immunostaining. Administration of a NOS inhibitor, N(G)-monomethyl-L-arginine (L-NMMA), reduced peak concentrations of nitrate in serum but did not affect survival. NO is induced by H250, both in vitro and in vivo, mainly via SPEA-independent mechanisms. In this model, iNOS is expressed predominantly in the liver. Furthermore, in this model L-NMMA is not protective.

Animals↗
PubMed1996

Lymphotoxin-alpha (TNF-beta) during sepsis.

T cell release of lymphotoxin-alpha (LT-alpha, or TNF-beta) is stimulated by pyrogenic exotoxins of Gram-positive bacteria and mitogens. In contrast to TNF-alpha, it is unknown whether LT-alpha plays any role in the pathogenesis of sepsis and, in particular, the pathogenesis of Gram-positive sepsis. Sera from patients with sepsis were examined for LT-alpha and compared with normal volunteers and pregnant women. LT-alpha was detected in 33% of sepsis sera (mean 608.4 pg/ml SE 306), 16% of normal sera (mean 167 pg/ml SE 87) and 23% of sera from pregnant women (mean 714 pg/ml SE 191). These differences were not significant and there were no differences within sepsis sera when grouped by the type of causative organism, or disease severity. LT-alpha detected by immunoassay in serum was not bioactive, in contrast to that produced in cell culture. Recombinant soluble TNF receptors (rSTNFR) neutralized the bioactivity of recombinant LT-alpha at rSTNFR concentrations which did not interfere with immunoreactivity and which are known to prevail in vivo. Hence, LT-alpha is unlikely to have a critical role in the pathogenesis of sepsis. Much of the potential bioactivity of this lymphokine may be abrogated by TNFR in serum.

Animals↗
PubMed1996

Streptococcal pyrogenic exotoxin A release, distribution, and role in a murine model of fasciitis and multiorgan failure due to Streptococcus pyogenes.

The role of streptococcal pyrogenic exotoxin A (SPEA) was evaluated in a murine model of fasciitis and multiorgan failure due to a toxigenic strain of Streptococcus pyogenes. Increased serum levels of SPEA at 15 and 21 h were associated with a survival time of <24 h. Levels of SPEA correlated with interleukin-6 levels. Immunostaining showed SPEA localized to renal and hepatic cells. Neutralizing rabbit antibody to SPEA was administered to mice challenged with S. pyogenes, but no effect on survival was observed. Vaccination of mice with recombinant SPEA enhanced mortality due to streptococcal infection, despite the development of neutralizing immunity to the toxin prior to infection. Hence, SPEA is produced systemically during S. pyogenes soft-tissue infection, and increased levels are associated with reduced survival. In this model, however, SPEA did not appear to play a dominant role in pathogenesis; passive immunization against SPEA was not protective, and active immunization enhanced mortality.

Animals↗
PubMed1995

Differences in the shedding of soluble TNF receptors between endotoxin-sensitive and endotoxin-resistant mice in response to lipopolysaccharide or live bacterial challenge.

TNF-alpha plays a pivotal role in the pathogenesis of septic shock. It exerts its effects by binding two cell surface receptors, designated TNF-R I and II, also referred to as the p55 and p75 receptors, respectively. TNF-Rs are transmembrane proteins, which on cleavage of their extracellular domains, result in the release of soluble fragments (sTNF-R). sTNF-R levels increase markedly during infection, and may serve to modulate TNF-alpha bioactivity. The mechanisms regulating this process are uncertain. To investigate this, we measured sTNF-R release in endotoxin-sensitive C3H/HeN and endotoxin-resistant C3H/HeJ mice given LPS or live Gram-negative bacteria. In C3H/HeN mice, there was a rapid early response during the first 4 h, and a second peak at 8 h, particularly noticeable in the case of the p75 receptor. Prior administration of neutralizing Abs to TNF-alpha or IFN-gamma had no effect on receptor shedding. Surprisingly, C3H/HeJ mice also responded to both bacterial challenge and to LPS by shedding sTNF-R; the magnitude and duration of the early response was not substantially different from C3H/HeN mice, although the second peak was absent. Peritoneal macrophages from C3H/HeN mice responded promptly (5 h) when stimulated with LPS in vitro, and by 22 h levels had increased five- to 10-fold. In contrast, cells from C3H/HeJ mice demonstrated only a very modest response at 22 h following maximal stimulation. The data suggest that there may be at least two separately regulated pathways that control sTNF-R shedding in these mice.

Animals↗
PubMed1995

Protective effects of a recombinant amino-terminal fragment of human bactericidal/permeability-increasing protein in an animal model of gram-negative sepsis.

Bactericidal/permeability-increasing protein (BPI) has bactericidal properties and also binds lipopolysaccharide (LPS). The ability of a recombinant amino-terminal fragment of BPI to protect mice from death after challenge with a number of different strains of Escherichia coli was tested. BPI prevented death in animals challenged with the J5 rough strain but not with smooth strains O111:B4 and O7K1. Protection was associated with a reduction in serum LPS and tumor necrosis factor-alpha levels but not with reduction in blood bacterial counts. BPI was effective at protecting against death in mice injected with purified O111:B4 LPS. Lack of protection after injection with live O111:B4 and O7K1 may be due to production by these models of approximately 1000-fold higher blood bacterial count compared with J5. Thus, BPI is a promising therapy in the treatment of gram-negative septic shock, although the range of organisms against which it is effective remains to be determined.

Animals↗
PubMed1995

A double-blind randomized prospective study comparing ondansetron with droperidol in the prevention of emesis following strabismus surgery.

A prospective double-blind study was conducted to compare the anti-emetic efficacy of ondansetron and droperidol in preventing postoperative emesis following strabismus surgery. A sample size of 213 patients was divided into three equal groups to receive ondansetron 150 micrograms/kg (Group A), ondansetron 75 micrograms/kg (Group B), or droperidol 75 micrograms/kg (Group C). All patients received a standardized anaesthetic technique. All episodes of emesis, recovery time, and time to tolerating oral fluids were recorded. The incidence of emesis during 24 hours was Groups A and B 19.7%, and Group C 28.2%. The lower incidence of emesis recorded by the ondansetron groups compared with the droperidol group was not statistically significant. Ondansetron at 75 micrograms/kg was as effective as 150 micrograms/kg in reducing emesis when compared with droperidol. Mean time to discharge from the recovery room was 75.3 minutes (Group A), 44.4 minutes (Group B), and 41.0 minutes (Group C). The mean time to tolerating oral fluids was 356.5 minutes (Group A), 402.8 minutes (Group B), and 378.1 minutes (Group C). There was no statistical difference in discharge times from recovery or time to tolerating oral fluids in any of the three groups.

Adult↗
PubMed1994

Protective effect of 55- but not 75-kD soluble tumor necrosis factor receptor-immunoglobulin G fusion proteins in an animal model of gram-negative sepsis.

The aim of this study was to compare the ability of both a 55- and 75-kD soluble tumor necrosis factor receptor immunoglobulin G fusion protein (sTNFR-IgG) in protecting against death in a murine model of gram-negative sepsis. Pretreatment with 250 micrograms of the p75 construct delayed but did not avert death in this model, reducing peak bioactive TNF-alpha levels after infection from 76.4 ng ml-1 in control mice to 4.7 ng ml-1 in the treated group (p < 0.05, two-sample t test). However, these low levels of bioactive TNF-alpha persisted in the p75 fusion protein-treated animals compared with the controls and were sufficient to mediate delayed death. In contrast, pretreatment with 200 micrograms of the p55 sTNFR-IgG gave excellent protection against death with complete neutralization of circulating TNF. Studies of the binding of TNF-alpha with the soluble TNFR fusion proteins showed that the p75 fusion construct exchanges bound TNF-alpha about 50-100-fold faster than the p55 fusion protein. Thus, although both fusion proteins in equilibrium bind TNF-alpha with high affinity, the TNF-alpha p55 fusion protein complex is kinetically more stable than the p75 fusion construct, which thus acts as a TNF carrier. The persistent release of TNF-alpha from the p75 fusion construct limits its therapeutic effect in this model of sepsis.

Animals↗
PubMed1993

High-dose adrenaline in adult in-hospital asystolic cardiopulmonary resuscitation: a double-blind randomised trial.

Forty intensive care unit patients requiring cardiopulmonary resuscitation were randomised to receive either the standard dose of adrenaline (1 mg every five minutes) or high-dose adrenaline (10 mg every five minutes). In the majority of patients, overwhelming sepsis was the major contributing factor leading to cardiac arrest. In this group of patients no difference could be detected in response to high-dose adrenaline compared with the standard dose. Although no side-effects were noted with this high dose of adrenaline, more investigation is required prior to its routine use in cardiopulmonary resuscitation.

Adult↗
PubMed1983

Effects of low intermittent concentrations of nitrous oxide on the developing rat fetus.

Five groups of 12 gravid female rats were exposed, during their entire gestation, intermittently for 6 h a day, 5 days per week, to 0.5% (5000 p.p.m.), 0.1% (1000 p.p.m.), 0.05% (500 p.p.m.) and 0.025% (250 p.p.m.) nitrous oxide-air mixtures (v/v), respectively. After killing the gravid rats on the 19th day of their pregnancies the numbers of corpora lutea of pregnancy were counted. Each uterus was examined for placentation sites and embryonic remnants and a detailed examination of the fetuses was undertaken. A significant reduction in mean litter size occurred only in the group exposed to 0.5% nitrous oxide in air (v/v). The mean litter sizes of the control and other exposed groups were comparable. No signs of fetal resorption or skeletal malformation were found in any group. The threshold of pollution for reduction in litter size has been shown in this study to lie between 0.1% and 0.5% nitrous oxide in air (v/v). A previous study on continuous exposure reported the threshold pollution to lie between 0.05% and 0.1% nitrous oxide in air (v/v). This investigation confirms that intermittent exposure to nitrous oxide-air mixtures increases the threshold for reproductive effects in rats.

Abnormalities, Drug-Induced↗
PubMed1983

Effects of intermittent 0.5% nitrous oxide/air (v/v) on the fertility of male rats and the post-natal growth of their offspring.

In a study of male rat fertility male Wistar albino rats were exposed to 0.5% nitrous oxide/air mixtures (v/v) for 30 days and control rats were exposed to oil-free air for the same time period. Thereafter each male was mated with three nulliparous female rats and mated again with three more nulliparous rats after a 6-month recovery period. The offspring were weighed and measured for 8 weeks postnatally. There was a significant reduction in mean litter size of the female rats mated with the male rats directly after the nitrous oxide exposure period. The offspring from the female rats mated with the males directly after the exposure period were significantly smaller in size than the control group. These results show a reversible reduction in male Wistar rat fertility, after exposure to 0.5% nitrous oxide in air (v/v), as well as a postnatal growth depression.

Animals↗
PubMed1981

Comparison of three anaesthetic scavenging devices using cuffed and noncuffed nasal endotracheal tubes during dental anaesthesia.

During maxillofacial and oral surgery the effect of three anaesthetic scavenging devices used with cuffed and non-cuffed endotracheal tubes was investigated. All the devices produced reductions in nitrous oxide concentrations in the breathing zone and peripheral air, ranging from 36% to 76%. Of the three devices evaluated, the Stellenbosch valve produced the greatest reduction in pollution compared with the control.

Air Pollution↗
PubMed1981

A simple air sampling technique for monitoring nitrous oxide pollution.

A simple, inexpensive device for the continuous low-flow sampling of air was devised to permit monitoring of pollution by gaseous anaesthetics. The device consisted of a water-filled Perspex cylinder in which a double-walled flexible-film gas sample collection bag was suspended. Air samples could be aspirated into the collection bag at flow rates of as low as 1 ml min-1 by allowing the water to drain from the cylinder at a controlled rate. The maintenance of sample integrity with aspiration and storage of samples of nitrous oxide in air at concentrations of 1000, 100 and 30 p.p.m. v/v was examined using gas chromatography. The sample bags retained a mean 94% of the nitrous oxide in air samples containing nitrous oxide 25 p.p.m. over a 72-h storage period.

Air Pollutants↗
PubMed1980

Early and late scavenging of anaesthetic gases.

The effectiveness of two waste gas scavenger devices, the Carstens box and the Ventex apparatus, with regard to nitrous oxide pollution was studied under comparable conditions in an operating theatre. The scavengers were brought into use in the early and late stages of induction of anesthesia, and nitrous oxide concentrations in the breathing zone and theatre peripheral air were measured. Both scavengers reduced nitrous oxide pollution at the sampling points. Similar reductions in nitrous oxide pollution in the breathing zone were obtained with both scavengers, but the Carstens box was more effective in reducing nitrous oxide pollution in the peripheral air.

Air Pollution↗