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Biomedical subjects

W D Cubitt

Publications and source records attributed to W D Cubitt.

At least 55 records · Page 3Linked to original sources
PubMed1990

Diagnosis of astrovirus gastroenteritis by antigen detection with monoclonal antibodies.

An enzyme-linked immunosorbent assay (ELISA), based on monoclonal antibodies to the astrovirus group antigen, was designed for the detection of astroviruses in stools of patients with gastroenteritis. Compared to immune electron microscopy used as the standard test, the sensitivity of the astrovirus ELISA was 91% (31/34) and the specificity was 96% (54/56). All five of the known astrovirus serotypes could be detected in 16 samples on which serotyping was done. In tests on 155 stools containing other enteric viruses, including adenoviruses, rotaviruses, caliciviruses, Hawaii virus, Snow Mountain virus, and Norwalk virus (30, 20, 70, 24, 4, and 7 samples, respectively), only 3 were positive in the astrovirus ELISA. The combined specificity for all astrovirus immune electron microscopy-negative samples was 98% (206/211). The results demonstrate that the new ELISA provides a sensitive and specific means for the diagnosis of astrovirus gastroenteritis.

Antibodies, Monoclonal↗
PubMed1989

Outbreaks of astrovirus type 1 and rotavirus gastroenteritis in a geriatric in-patient population.

Two outbreaks of viral gastroenteritis occurred in seven psychogeriatric wards of a 469-bed psychiatric hospital. The outbreaks occurred over an eight-week period; the first affected 30 people and rotavirus was detected in 12 of 14 persons from whom faecal specimens were available. The second affected 32 people (15 of whom were affected in the previous outbreak) and astrovirus was detected in 5 of the 24 people from whom specimens were available. Specific IgM to astrovirus was demonstrated in 3 patients. The rotavirus outbreak was characterised by a longer duration of illness (mean 4 days), and more severe symptoms; two elderly female patients had severe symptoms over a 14-15 day period but recovered. In the astrovirus outbreak the duration of illness was shorter and symptoms were milder although the attack rate was higher than that observed for rotavirus.

Adult↗
PubMed1989

Group C rotavirus infections in patients with diarrhea in Thailand, Nepal, and England.

Atypical rotavirus obtained from fecal specimens of six patients with diarrhea from Thailand, Nepal, and England were characterized by using polyacrylamide gel electrophoresis and immune electron microscopy. The electropherotypes were characteristic of the porcine reference group C rotavirus strain but demonstrated considerable strain-to-strain variation. Human convalescent group C sera had a high titer (1:320) when tested against the human isolates and a low titer (1:40) when tested against a porcine reference strain (Cowden). When porcine antiserum (Cowden) was tested against the human isolates, the titers ranged from 1:40 to 1:320, indicating significant antigenic diversity between strains. Group C rotavirus appears to have a worldwide distribution as an agent associated with diarrhea in children and adults.

Adult↗
PubMed1988

Systemic lymphoproliferative responses to rotavirus.

In comparison with healthy adults, elderly patients and patients who had received renal transplants had significantly lower lymphoproliferative responses to rotavirus (P = 0.04, P = 0.002, respectively) and phytohaemagglutinin (P = 0.001). However, following acute rotavirus infection, elderly persons mounted good lymphoproliferative and specific antibody responses to rotavirus. No lymphoproliferative response or specific antibody to rotavirus was detected in a child with cartilage hair hypoplasia. In cord blood samples, specific antibodies were detected in the absence of a lymphoproliferative response to rotavirus. Increases in lymphoproliferative responses as well as specific antibodies were not detected in immune adult recipients of a human rotavirus vaccine (RIT 4375), but a recipient of a bovine vaccine (RIT 4237) had an increase in lymphoproliferative response to rotavirus between 13 and 28 days postvaccination. Stimulation indices for both rotavirus and phytohaemagglutinin within the vaccine groups were comparable to the healthy laboratory personnel group.

Adult↗
PubMed1988

The development and evaluation of radioimmune assays for the detection of immune globulins M and G against astrovirus.

The development and evaluation of radioimmune assays for the detection of IgM and IgG antibodies to astrovirus are described. The test was shown to be sensitive and specific, and suitable for screening large numbers of sera. The use of the assays has established that astrovirus type 1 is prevalent in the United Kingdom and that not only infants but also schoolchildren and elderly patients are affected. Further evidence is given to support the view that Marin County Agent is antigenically related to astrovirus type 1.

Adult↗
PubMed1987

The candidate caliciviruses.

The Caliciviridae are a family of small (35-40 nm) RNA viruses with a characteristic cupped morphology. They are unique in possessing only a single major structural polypeptide, of Mr 60,000-71,000. The use of electron microscopy to investigate diarrhoeal diseases has revealed viral particles with the size and structure of the caliciviruses in the faeces of humans, domestic and farm animals, birds, reptiles and insects. In vivo experiments indicate that they are species specific and have confirmed that they replicate in the gut, which often results in the host developing diarrhoea and failing to thrive. Biochemical characterization of these agents has been hampered by a failure to produce sufficient yields of virus in vitro. However, fluorescence and radiolabelling experiments indicate that the human, canine and chicken viruses replicate in the cytoplasm and possess an RNA genome. A major structural polypeptide (Mr 60,000-71,000) has been identified in the human, canine and insect viruses. Diagnosis of the candidate caliciviruses is dependent on electron microscopy and fluorescence labelling, with the exception of the human agents, for which radioimmunoassays have been developed. There is little epidemiological information on these agents but there is increasing evidence that the human caliciviruses are a common cause of outbreaks of diarrhoea and vomiting in infants, adults and the elderly.

Animals↗
PubMed1987

Immunobiology of Norwalk virus.

Clinical immunity to Norwalk virus in inoculated human volunteers appears to be unusual for gastroenteritis viruses, as certain individuals are repeatedly ill on long-term virus rechallenge and others remain persistently well. In these volunteers there is a paradoxical inverse correlation between the prechallenge serum (and jejunal fluid) Norwalk antibody level (measured by radioimmunoassay) and resistance to illness, suggesting that non-immunological factors, perhaps genetic, may be important in determining resistance. Most reported naturally occurring Norwalk disease outbreaks in developed nations also show that humoral antibody fails to correlate with immunity to infection. The unusual pattern of clinical immunity to Norwalk virus indicates a need for caution in the development of vaccines against this agent as well as a need for additional information on its immunobiological characteristics. The virus is known to contain a single protein, like the caliciviruses. Recently we have found evidence for at least a one-way serological cross-relatedness between Norwalk virus and human calicivirus. Twelve of 20 paired sera from ill patients in outbreaks due to calicivirus strain UK4 seroconverted to Norwalk virus by radioimmunoassay and two of eight paired sera from UK2 outbreaks showed seroconversion. Future studies of outbreaks caused by various calicivirus strains should be designed to correlate acute-phase serum antibody titres to Norwalk virus with clinical susceptibility and immunity to infection.

Antibodies, Viral↗
PubMed1987

Seroepidemiological survey of the prevalence of antibodies to a strain of human calicivirus.

Batches of pooled immune globulins and sera were tested by immune electron microscopy (IEM) for the presence of antibodies to a strain of human calicivirus (HCV, UK1). The results show that this strain of HCV is prevalent throughout many parts of the world and that the majority of the population experience infection by the age of 12 years. The survey carried out in the United Kingdom indicates that the presence of maternal antibody correlates with some degree of protection during the first few weeks of life; the peak incidence of cases and acquisition of antibody occur between 3 months and 6 years. Tests on sera from Japan show a similar pattern of acquisition of antibodies and demonstrate that infection with more than one strain of HCV commonly occurs during childhood.

Adolescent↗
PubMed1987

An outbreak of gastroenteritis in a home for the elderly associated with astrovirus type 1 and human calicivirus.

We describe an outbreak of gastroenteritis, which lasted for 22 days in a residential home for the elderly. The outbreak was biphasic and affected 34/42 (80%) residents and 13/29 (44%) members of the staff. Calicivirus was associated with cases of illness during the first 9 days of the outbreak, and astrovirus type 1 with cases arising between days 16 to 22. Although the symptoms were generally mild, the resources required and the inconvenience caused were considerable.

Aged↗
PubMed1987

Antigenic relationships between human caliciviruses and Norwalk virus.

We investigated antigenic relationships between human calicivirus (HCV) strains and Norwalk virus by using immune electron microscopy (IEM) and radioimmunoassay (RIA). Three serologically distinct HCV strains, UK1, UK2, and Japan, were demonstrated by IEM, as was evidence for two additional strains, UK3 and UK4. Although HCV strains and Norwalk virus were distinct by IEM, 12 of 20 patients with gastroenteritis due to HCV UK4 and two of eight with gastroenteritis due to UK2 showed seroconversions to Norwalk virus by RIA. These naturally occurring antibody responses in humans, as detected by RIA, support the concept that Norwalk virus belongs to the family Caliciviridae. An RIA for HCV Japan antigen also detected HCV UK1, UK2, and UK4 and thus appears to identify a group-specific antigen for these viruses. An RIA for antibody to HCV Japan failed to identify seroconversions in 45 of 47 patients with gastroenteritis due to HCV UK. These results may reflect different reactivities of various immunologic tests for the identification of infections due to small gastroenteritis viruses.

Animals↗
PubMed1986

Aplastic and hypoplastic episodes in sickle cell disease and thalassaemia intermedia.

Aplastic and hypoplastic crises are well recognised complications of sickle cell disease. Recent evidence has shown that most of these crises are caused by parvovirus infection. Five cases of aplastic or hypoplastic crises in patients born and living in this country were studied. Three patients had clear evidence of parvovirus infection, while in two evidence of parvovirus infection was lacking. One patient had evidence of concurrent parvovirus and Mycoplasma pneumoniae infection. Recurrent crises may occur, and reticulocyte monitoring during infection in patients with chronic haemolytic states is therefore important.

Adolescent↗
PubMed1985

Characterization of a new calicivirus isolated from feces of a dog.

Canine calicivirus (CaCV), isolated from feces of a dog with diarrhea, was readily propagated in cultures of canine cells and in a dolphin cell line. Serologic evidence indicated many dogs in at least one geographic area had been infected with CaCV, but its role as an etiologic agent of disease was not established. In cell culture most CaCV virions were strongly cell-associated making purification difficult. CaCV was established as a member of the Caliciviridae by morphology and physicochemical properties of virions (density, sedimentation rate, single major polypeptide, RNA genome size), although some of the properties differed slightly from those of previously described caliciviruses; evidence was also obtained for caliciviral RNA species in infected cells. Based on tests with antisera to numerous caliciviruses and presumed caliciviruses, CaCV appeared to be not closely related to any previously described virus except the stunting syndrome agent of chickens.

Animals↗
PubMed1985

Propagation and preliminary characterization of a chicken candidate calicivirus.

The present paper reports the propagation and partial characterization of calici-like virus particles previously observed in gut homogenates obtained from stunted broiler chicks. Radiolabelling experiments with [3H]uridine showed that the virus possesses an RNA genome and that it can replicate in primary chick embryo fibroblasts in the presence of actinomycin D. In vivo studies showed that the virus can be serially passaged in specific pathogen-free chicks and virus particles can be recovered from the gut and excreta of infected birds. The morphological appearance and biophysical properties of the virus were similar to those of feline calicivirus, which supports the view that it should be tentatively classified as a member of the Caliciviridae.

Animals↗
PubMed1984

An outbreak of calicivirus associated gastroenteritis in an elderly persons home. A possible zoonosis?

An outbreak of gastroenteritis caused by calicivirus began amongst residents and staff of an old persons home 24 hours after the proprietor's dog had been sick. Serological evidence suggests that the calicivirus isolated from one of the cases may be capable of infecting dogs as well as man. The virus strain responsible for this outbreak differs antigenically from those associated with two other outbreaks in the U.K. and one in Japan. The characteristic morphology of calicivirus is lost if stool is stored at -70 degrees C.

Aged↗
PubMed1984

Defective interfering particles of Semliki Forest virus are smaller than particles of standard virus.

By electron microscopy, particles of defective interfering Semliki Forest virus (DI SFV) had a mean diameter of 46.8 nm compared with 55.9 nm for standard virus particles, a decrease of 16%. The difference was confirmed by measurements of the two-dimensional projected areas of DI and standard virus particles. We examined nine different DI virus preparations produced by four to 13 undiluted passages in BHK cells and all were found to contain a majority of the smaller type of particle. Calculation of the absolute number of small particles showed that there were 130 particles per interfering unit measured by the inhibition of virus RNA synthesis. However, a more sensitive assay based on interference with virus protein synthesis gave a particle: interference ratio of 6.5.

Defective Viruses↗
PubMed1984

Propagation of human candidate calicivirus in cell culture.

Evidence is presented for the first time that a human candidate calicivirus (HCV) replicates in human embryo kidney cells when trypsin is incorporated in the culture medium. The virus multiplies in the presence of actinomycin D and radiolabelling experiments with [3H]uridine indicate that it has an RNA genome. These observations provide further support for the view that HCV should be tentatively classified as a member of the Caliciviridae .

Caliciviridae↗