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Biomedical subjects

R A French

Publications and source records attributed to R A French.

At least 19 recordsLinked to original sources
PubMed2006

An evaluation of the GlideScope, a new video laryngoscope for difficult airways: a manikin study.

BACKGROUND AND OBJECTIVES: The GlideScope is a new video laryngoscope. The aim of our study was to assess its use compared to a Macintosh blade in airway scenarios on the Airman airway simulator. The scenarios were: 'normal' or resting state of the manikin, pharyngeal obstruction, cervical rigidity and tongue oedema. METHODS: Thirty anaesthetists from the Christchurch Anaesthetic Department attempted to pass a bougie or stylet through the vocal cords of the manikin with a size 3 Macintosh blade, then the GlideScope. View at laryngoscopy, ease of 'intubation' and whether they thought the GlideScope would be useful in clinical practice were recorded. RESULTS: Forty three percent (P = 0.02) found an improved view with the GlideScope in the pharyngeal obstruction scenario. In the other scenarios there was no significant difference in view. Reportage of ease of intubation showed no statistical difference in any scenarios. However, 93% of anaesthetists considered having the GlideScope would be useful if faced clinically with one or more of the studied scenarios. CONCLUSIONS: The GlideScope improved the view in one of three difficult airway situations when used by anaesthetists with no formal training in its use. No single airway device offers a solution to all scenarios, however, we consider that the GlideScope is a useful addition to the range of difficult airway devices available.

Airway Obstruction↗
PubMed2005

Mutation of E1 glycoprotein of classical swine fever virus affects viral virulence in swine.

Transposon linker insertion mutagenesis of a full-length infectious clone (IC) (pBIC) of the pathogenic classical swine fever virus (CSFV) strain Brescia was used to identify genetic determinants of CSFV virulence and host range. Here, we characterize a virus mutant, RB-C22v, possessing a 19-residue insertion at the carboxyl terminus of E1 glycoprotein. Although RB-C22v exhibited normal growth characteristics in primary porcine macrophage cell cultures, the major target cell of CSFV in vivo, it was markedly attenuated in swine. All RB-C22v-infected pigs survived infection remaining clinically normal in contrast to the 100% mortality observed for BICv-infected animals. Comparative pathogenesis studies demonstrated a delay in RB-C22v spread to, and decreased replication in the tonsils, a 10(2) to 10(7) log10 reduction in virus titers in lymphoid tissues and blood, and an overall delay in generalization of infection relative to BICv. Notably, RB-C22v-infected animals were protected from clinical disease when challenged with pathogenic BICv at 3, 5, 7, and 21 days post-RB-C22v inoculation. Viremia, viral replication in tissues, and oronasal shedding were reduced in animals challenged at 7 and 21 DPI. Notably BICv-specific RNA was not detected in tonsils of challenged animals. These results indicate that a carboxyl-terminal domain of E1 glycoprotein affects virulence of CSFV in swine, and they demonstrate that mutation of this domain provides the basis for a rationally designed and efficacious live-attenuated CSF vaccine.

Amino Acid Sequence↗
PubMed2005

Preclinical diagnosis of African swine fever in contact-exposed swine by a real-time PCR assay.

A fluorogenic probe hydrolysis (TaqMan) PCR assay for African swine fever virus (ASFV) was developed and evaluated in experimentally infected swine. This sensitive and specific one-step single-tube assay, which can be performed in 2 h or less, detected viral DNA in tonsil scraping samples 2 to 4 days prior to onset of clinical disease. Thus, the assay would have application for preclinical diagnosis of African swine fever and surveillance and/or emergency management of a disease outbreak.

African Swine Fever↗
PubMed2005

The E2 glycoprotein of classical swine fever virus is a virulence determinant in swine.

To identify genetic determinants of classical swine fever virus (CSFV) virulence and host range, chimeras of the highly pathogenic Brescia strain and the attenuated vaccine strain CS were constructed and evaluated for viral virulence in swine. Upon initial screening, only chimeras 138.8v and 337.14v, the only chimeras containing the E2 glycoprotein of CS, were attenuated in swine despite exhibiting unaltered growth characteristics in primary porcine macrophage cell cultures. Additional viral chimeras were constructed to confirm the role of E2 in virulence. Chimeric virus 319.1v, which contained only the CS E2 glycoprotein in the Brescia background, was markedly attenuated in pigs, exhibiting significantly decreased virus replication in tonsils, a transient viremia, limited generalization of infection, and decreased virus shedding. Chimeras encoding all Brescia structural proteins in a CS genetic background remained attenuated, indicating that additional mutations outside the structural region are important for CS vaccine virus attenuation. These results demonstrate that CS E2 alone is sufficient for attenuating Brescia, indicating a significant role for the CSFV E2 glycoprotein in swine virulence.

Animals↗
PubMed2001

Development of a multiplex PCR for the detection of Haplosporidium nelsoni, Haplosporidium costale and Perkinsus marinus in the eastern oyster (Crassostrea virginica, Gmelin, 1971).

Haplosporidium costale (SSO), Haplosporidium nelsoni (MSX) and Perkinsus marinus (Dermo) have caused oyster mortality on the North American east coast since the 1950s. Currently, the monitoring of oyster populations for these pathogens depends on histopathology for H. nelsoni, H. costale and the Ray/Mackin assay for P. marinus. In this study we describe the development and optimization of a multiplex polymerase chain reaction (MPCR) for the detection of H. nelsoni, H. costale and P. marinus. In addition, we determine its specificity and sensitivity. The MPCR clearly detects and differentiates the protozoan pathogens. There was no cross-reactivity between these species. The MPCR was able to detect DNA from H. nelsoni as low as 10 fg and P. marinus and H. costale as low as 1 pg. The MPCR allows for the detection of H. nelsoni, H. costale and P. marinus in a single PCR reaction.

Animals↗
PubMed2001

A breathing circuit disconnection detected by anesthetic agent monitoring.

PURPOSE: To describe a case involving a spontaneously breathing patient where a circuit disconnection was detected by a change in monitored anesthetic agent parameters. CLINICAL FEATURES: A patient undergoing shoulder surgery was breathing spontaneously from a circle type anesthesia circuit via a laryngeal mask. A disconnection occurred between the heat and moisture exchanger (HME) and the circle system's Y-piece. As the gas sampling port was integrated into the HME a near normal pattern of CO2 continued to be displayed. The disconnection was noted because of a change in the graphical display of the volatile agent concentration. CONCLUSIONS: Anesthetic circuit disconnection can be difficult to detect, especially in the spontaneously breathing patient. Capnometry may not detect a disconnection on the machine side of the gas sampling port. Changes in oxygen and volatile agent concentrations may provide an early indication of these types of disconnection.

Anesthesiology↗
PubMed2001

The West Nile virus: its recent emergence in North America.

West Nile fever emerged in New York in the summer of 1999 when seven people, several horses and thousands of wild birds died. It was soon established that the human disease and the mortality of birds were related. Continued surveillance detected West Nile virus in mosquitoes, birds, horses, small mammals, bats and humans, and has shown its spread to several northeastern states. These events confirm the establishment of West Nile virus endemically in the United States.

Aged↗
PubMed2000

Recovery and identification of West Nile virus from a hawk in winter.

West Nile virus was recovered from the brain of a red-tailed hawk that died in Westchester County, N.Y., in February 2000. Multiple foci of glial cells, lymphocytes, and a few pyknotic nuclei were observed in the brain. Three to 4 days after inoculation of Vero cells with brain homogenates, cytopathic changes were detected. The presence of West Nile virus antigen in fixed cells or cell lysates was revealed by fluorescent antibody testing or enzyme-linked immunosorbent assay, respectively. Furthermore, Reverse transcriptase-PCR with primers specific for the NS3 gene of West Nile virus resulted in an amplicon of the expected size (470 bp). Electron microscopy of thin sections of infected Vero cells revealed the presence of viral particles approximately 40 nm in diameter, within cytoplasmic vesicles. The demonstration of infection with the West Nile virus in the dead of the winter, long after mosquitoes ceased to be active, is significant in that it testifies to the survival of the virus in the region beyond mosquito season and suggests another route of transmission: in this case, prey to predator.

Animals↗
PubMed1999

Isolation of West Nile virus from mosquitoes, crows, and a Cooper's hawk in Connecticut.

West Nile (WN) virus, a mosquito-transmitted virus native to Africa, Asia, and Europe, was isolated from two species of mosquitoes, Culex pipiens and Aedes vexans, and from brain tissues of 28 American crows, Corvus brachyrhynchos, and one Cooper's hawk, Accipiter cooperii, in Connecticut. A portion of the genome of virus isolates from four different hosts was sequenced and analyzed by comparative phylogenetic analysis. Our isolates from Connecticut were similar to one another and most closely related to two WN isolates from Romania (2.8 and 3.6 percent difference). If established in North America, WN virus will likely have severe effects on human health and on the health of populations of birds.

Aedes↗
PubMed1999

Therapeutic vaccination with p24-VLP and zidovudine augments HIV-specific cytotoxic T lymphocyte activity in asymptomatic HIV-infected individuals.

This study evaluates the impact of therapeutic vaccination with p24-VLP and zidovudine on the induction or maintenance of HIV-specific cytotoxic lymphocyte activity in a cohort of asymptomatic patients with CD4 counts greater than 400 cells/microl. In a dummy, randomized, phase II clinical trial of the therapeutic vaccine, participants were randomized to one of three arms for 6 months: p24-VLP (500 microg) in alum monthly plus zidovudine 200 mg tds, alum adjuvant plus zidovudine, or p24-VLP plus placebo. Subjects were studied for a total of 52 weeks from baseline. Monitoring included viral load, CD4 and CD8 counts, markers of immune activation, delayed-type hypersensitivity (DTH) skin testing, and cytotoxic T lymphocyte (CTL) measurement. The nine subjects who received p24-VLP and zidovudine had an augmentation and/or broadening of their CTL response compared with baseline (p = 0.004). The eight subjects receiving p24-VLP and seven subjects receiving zidovudine did not have a statistically significant increase or broadening of CTL activity. The augmentation of the CTL response in the subjects who received p24-VLP and zidovudine was not associated with a decline in viral load or an increase in CD8 counts. This study suggests that HIV-specific CTL activity can be augmented in HIV-infected individuals receiving p24-VLP and zidovudine, supporting the hypothesis of therapeutic vaccination in the presence of antiretroviral therapy.

AIDS Vaccines↗
PubMed1999

Expression and localization of p80 and p68 interleukin-1 receptor proteins in the brain of adult mice.

The biological effects of interleukin-1 (IL-1) are mediated by two distinct receptors, the p80 type I IL-1 and p68 type II IL-1 receptor proteins (IL-1RI and IL-1RII, respectively), both of which have been recently co-localized to the growth hormone synthesizing cells of the adenohypophysis. Previous studies have shown that IL-1 can bind to specific structures in the central nervous system, but the distribution of IL-1RI and IL-1RII proteins in the adult mouse brain has not been reported. Here we have used immunohistochemistry to study the expression, distribution and cellular localization of both isoforms of the IL-1 receptor proteins in the adult mouse brain. Using a combination of processing techniques (AMeX fixation and cryosectioning), we have immunolabeled brain sections for each isoform of the IL-1R. Both isoforms are expressed in the CNS, particularly in neuronal soma of the granular layer of the dentate gyrus and pyramidal cells of fields CA1-CA4 of Ammon's horn of the hippocampus, in epithelial cells of the choroid plexus and ependymal layer, and in neuronal soma of Purkinje cells of the cerebellum. The IL-1RII isoform, but not IL-1RI, is expressed in specific neuronal soma and proximal cell processes of neurons of the paraventricular gray matter of the hypothalamus. These immunohistochemical data directly demonstrate the neuronal expression of both IL-1R proteins in situ. The distribution and cellular localization of IL-1R proteins in the CNS provide a molecular basis for understanding reciprocal interactions between the immune system and the brain.

Age Factors↗
PubMed1999

An "enigmatic" cause of back pain following regional anaesthesia for caesarean section: septic pelvic thrombophlebitis.

A case of septic pelvic thrombophlebitis is reported. This presented as back pain and leg weakness 18 days after regional anaesthesia for caesarean section. The patient was referred to the Department of Anaesthesia. Obstetric review of the patient at the request of the anaesthetist led to a CT scan that demonstrated the diagnosis. This condition may lead to fatal "on-table" pulmonary embolus if the thrombosed vein is handled during an exploratory laparotomy. Treatment should be conservative with antibiotics and anticoagulation. This case illustrates the need for awareness amongst anaesthetists of possible surgical causes for morbidity that may initially appear anaesthetic-related.

Adult↗
PubMed1998

Disconnect alarm failure in detection of common gas outlet disconnection.

This laboratory study was prompted by two paediatric cases where low pressure alarms and capnography failed to detect common gas outlet disconnection when using a T-piece pump ventilator. A carbon dioxide producing model lung was ventilated using the Clare ventilator (a T-piece pump type ventilator) via an Ayres T-piece. The T-piece used has 3 mm diameter fresh gas tubing. Common gas outlet disconnects were carried out using varying fresh gas flows and ventilatory patterns. At fresh gas flows of less than 8 l/min, the low pressure alarm of the Clare ventilator failed to sound following common gas outlet disconnection. Oxygraphy showed a rapid rise in inspired oxygen. End-tidal CO2 rose, whilst inspired CO2 remained at zero. This experiment demonstrates that the Clare ventilator's low pressure alarm detects common gas outlet disconnection poorly when used with an Ayres T-piece with narrow fresh gas tubing. Graphical representation of airway oxygen content has merit as an alerting monitor for common gas outlet disconnection.

Anesthesiology↗
PubMed1997

Mouse Moloney leukemia virus infects microglia but not neurons even though it induces motor neuron disease.

Motor neuron degeneration caused by ts1 MoMuLV occurs by an indirect mechanism and hypothetically appears associated with a two-cell or three-cell pathogenesis hypothesis. The first step in this hypothesis is associated with a small subset of resident microglial cells that serve as the principal target cells for ts1 MoMuLV infection. The second step is likely linked to trophic events, probably mediated by cytokines, that lead to hypertrophy and activation of a substantial number of additional microglial cells (autocrine effect) and adjacent astrocytes (paracrine effect). The third step in this hypothesis appears related to indirect neuronal degeneration mediated by cytotoxins produced by activated microglial cells and astrocytes. In this last step, motor neurons located within these foci of activated microglial cells and astrocytes are 'innocent bystander cells' and degenerate and die due to paracrine effects. The mechanism of motor neuron degeneration is poorly understood but is likely linked to a sequential cascade of trophic factors and cytokines resulting in a final common pathway for motor neuron death involving production of oxidative radicals, excitatory aminoacid neurotransmitter-like substances, prostaglandins, or nitric oxide.

Animals↗
PubMed1997

Neuronal vacuolation and spinocerebellar degeneration in young Rottweiler dogs.

With the recent epizootic of bovine spongiform encephalopathy in Europe, the differential diagnosis of neuronal vacuolation and spongiform change in other species has become critically important. Four Rottweiler puppies of both sexes, presented at 3-8 months of age, had clinical signs of generalized weakness and ataxia that started at 6 weeks of age. In all pups, neurologic examination detected an ataxia and tetraparesis, most severe in the pelvic limbs, and slowed proprioceptive placing reactions. Subsequently, there was rapid progressive neurologic deterioration, with severe placing deficits, knuckling, severe ataxia, and quadraparesis by 8 months of age. At necropsy, no gross lesions were observed. Microscopic lesions were restricted to the nervous system. The major lesion in all dogs was an intracytoplasmic neuronal vacuolation that was most prominent in the cerebellar roof nuclei and in nuclei of the extrapyramidal system. Similar vacuolation was found in neurons in both dorsal nerve root ganglia, myenteric plexus, and other ganglia of the autonomic nervous system. The single or multiple empty vacuoles were between 1 and 45 microm in diameter. A mild spongiform change was seen in the adjacent neuropil. Purkinje cell vacuolation and degeneration with segmental cell loss was seen in the oldest dog. In ventromedial and dorsolateral areas of the spinal cord white matter, there was mild bilaterally symmetrical axonal degeneration. Immunoblotting and immunocytochemical staining of the brain for protease-resistant scrapie prion protein was negative. All forms of vacuoles were negative for immunohistochemical staining with a variety of lectins. Ultrastructurally, the vacuoles were bound by a single membrane and contained granular material and sometimes membranous profiles. There was mild distension of the cytocavitary network but no unequivocal connection with the vacuoles was found. Axosomatic and axodendritic synapses in affected neurons were intact both ultrastructurally and with synaptophysin immunostaining. The clinicopathologic findings were different from those seen in the other neurologic diseases of Rottweilers. The age of the dogs, distribution and type of the lesions, ultrastructural findings, and negative immunoblotting most likely rule out the possibility of a scrapie agent-associated spongiform encephalopathy. However, the etiology of this new disease was not determined.

Animals↗
PubMed1996

Eosinophilic colitis and hepatitis in a horse with colonic intramucosal ciliated protozoa.

Tissues from a 9-year-old American Standardbred gelding with a history of anorexia, mild colic, and unexpected death were submitted to the Laboratories of Veterinary Diagnostic Medicine at the University of Illinois for histopathologic examination. Microscopic diagnoses were severe subacute, diffuse eosinophilic colitis with intralesional protozoa and a subacute to chronic eosinophilic portal hepatitis with granuloma formation. Two tissue-invading, ciliated protozoa were identified in large numbers within the colonic mucosa. The ciliates were Polymorphella ampulla and Cycloposthium sp., Phylum:Ciliophora. The eosinophilic colitis and portal hepatitis in association with the overpopulation and invasion by the ciliated protozoa suggests a causal etiology.

Animals↗
PubMed1996

Primary epitheliotropic alimentary T-cell lymphoma with hepatic involvement in a dog.

The anatomic forms of lymphoma are multicentric, alimentary, thymic, cutaneous, and leukemic. Correlations between cell type and topographic distribution of lymphomas is not well documented, but there are more plasmacytoid tumors in the gut, skin, and spleen, which suggests that these are areas of malignant transformation preceded by a period of benign immune hyperplasia. Alimentary forms of lymphoma can be preceded by lymphocytic-plasmacytic enteritis. In the present case, an epitheliotropic alimentary form of T-cell lymphoma with hepatic involvement and concomitant lymphocytic-plasmacytic enteritis was diagnosed in an 8-year-old male Labrador Retriever. The lymphoma was characterized by the accumulation of atypical lymphocytes in the lamina propria and mucosal epithelium of the jejunum. The lymphocytes were identified as T-cell lineage using a polyclonal rabbit antisera to the human pan-T-cell determinant CD-3. The "homing" nature of the neoplasm resembles the epidermotropic form of cutaneous T-cell lymphoma.

Animals↗