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Biomedical subjects

P J Middleton

Publications and source records attributed to P J Middleton.

At least 19 recordsLinked to original sources
PubMed1990

Rapid immunoblot method for diagnosis of acute Mycoplasma pneumoniae infection.

A rapid immunoblotting technique based on the IgM response to a major immunogenic protein is described for the diagnosis of Mycoplasma pneumoniae infection. Using results of the complement fixation test as the criterion for diagnosis, the rapid immunoblot method was positive in 95.7% of patients. The sensitivity was reduced to 81.9% if the test was performed on either single sera or acute sera only from serum pairs. Although the few sera that failed to demonstrate a positive IgM response were more likely to be from older patients, there was a consistent IgM response recorded for both younger (less than 20 years) and older (greater than or equal to 20 years) patients.

Antibodies, Bacterial↗
PubMed1990

Time-resolved fluoroimmunoassay for enteric adenoviruses using the europium chelator 4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid.

A time-resolved fluoroimmunoassay (TR FIA) was developed for the direct detection of adenovirus types 40 (Ad40) and 41 (Ad41) in stool specimens by using a monoclonal antibody (5D8/2C2) which recognizes both Ad40 and Ad41 but does not cross-react with other adenovirus serotypes. In this assay, the detector antibody is biotinylated directly rather than labeled with europium, and the fluorescent signal is generated on a solid phase in the presence of excess europium (Eu3+). The strength of the signal is dependent on the amount of a Eu3+ chelator [4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid (BCPDA)]-streptavidin complex bound by the biotinylated detector antibody (5D8/2C2). In a pilot study with 41 specimens, this TR FIA demonstrated a maximum sensitivity and specificity of 88% compared with SmaI restriction analysis of adenovirus isolates from the same specimens. TR FIA using the europium chelator BCPDA represents a feasible approach for the direct identification of specific adenovirus serotypes in stool specimens.

Adenoviridae↗
PubMed1990

Clinical features of adenovirus enteritis: a review of 127 cases.

We retrospectively analyzed the clinical features of 127 hospitalized pediatric patients whose fecal samples were positive for adenovirus (Ad) by electron microscopy during an 18-month period. Serotyping results obtained by microneutralization tests and restriction endonuclease analysis were available for 105 of 127 cases. There were 69 males and 58 females and 94% of patients were less than 4 years of age. The average body temperature was 38 degrees C rectal (range, 36.2-40.8 degrees C) with an average duration of fever of 1.6 days. The average duration of clinical illness was 8.8 days (range, 1 to 32 days). Although Ad 40 and Ad 41 were isolated in the majority of cases (59 of 105 (56%], Ad 31 was associated with 18 of 105 cases (17%). Of the 18 cases associated with Ad 31, 14 were nosocomial and associated with diarrhea. Our survey confirms the importance of fastidious enteric Ad in infantile diarrhea (Ad 40, Ad 41) and suggests that Ad 31 produces a clinical syndrome indistinguishable from that caused by Ad 40 and Ad 41. The occurrence of Ad enteritis in patients admitted for unrelated illnesses well after initial hospitalization suggests that Ad is also an important cause of nosocomial enteritis in our hospital.

Adenovirus Infections, Human↗
PubMed1989

Mycoplasma pneumoniae associated arthropathy: confirmation of the association by determination of the antipolypeptide IgM response.

The association of Mycoplasma pneumoniae with arthropathy in children and young adults has been established essentially on the basis of complement fixation (CF) serology. Because the CF test may be nonspecific for M. pneumoniae, we have confirmed the association by determination of IgM ELISA and IgM and IgG immunoblotting responses in 2 children. Mycoplasma pneumoniae should be considered in any patient with acute respiratory illness who subsequently develops arthropathy.

Antigens, Bacterial↗
PubMed1979

Influenza A virus associated with acute encephalopathy.

During the period of February 1972 until February 1976, we documented six cases of influenza A-associated acute encephalopathy. The illnesses occurred during periods of influenza A activity in our community. The encephalopathy was invariably preceded by an upper respiratory tract infection, and, thereafter, patients soon became confused, vomited, and showed noticeable restlessness. Patients then followed either of two courses, some becoming comatose within 24 hours and others improving rapidly within three days or less. None of these patients exhibited the hepatic and biochemical abnormalities associated with Reye's syndrome. All patients survived but some had sequelae. The syndrome of influenza-associated acute encephalopathy deserves wider recognition.

Adolescent↗
PubMed1979

Hepatitis B-associated membranous glomerulonephritis in a child.

This appears to be the first reported case of membranous glomerulonephritis in a pediatric asymptomatic carrier of hepatitis B virus in North America. Routine immunofluorescent methods were used to identify the hepatitis B surface antigen in glomeruli. In addition, the glomerular immune deposits were searched for the known ultrastructural forms of the virus.

Biopsy↗
PubMed1979

Counterimmunoelectrophoresis assay for detection of adenovirus antigen.

A rapid, sensitive counterimmunoelectrophoresis assay was developed to detect adenovirus in stools of patients with gastroenteritis. The parameters of the assay were optimized, and its sensitivity and efficiency was examined. The assay promises to be a useful alternative to conventional techniques of cell culture isolation or electron microscopy for the detection of adenovirus in stool specimens.

Adenovirus Infections, Human↗
PubMed1979

Detection of adenovirus antibody by counterimmunoelectrophoresis.

Counterimmunoelectrophoresis was adapted as a rapid, sensitive assay for detection of adenovirus group-specific antibody. This assay was six times more sensitive than the complement fixation test and was successfully adapted for use with microliter quantities of serum or whole blood.

Adenoviruses, Human↗
PubMed1979

Enteric adenoviruses: detection, replication, and significance.

Adenoviruses can be demonstrated readily in the stools of pediatric gastroenteritis patients by electron microscopy or counterimmunoelectrophoresis, but in 45% of these cases the virus will not grow in cell culture. Indirect immunofluorescence microscopy can be used to detect nongrowing strains of adenovirus; these strains have a unique single-cell fluorescence pattern. Hematoxylin and eosin staining reveals adenovirus-like inclusion bodies in the same distribution as fluorescent cells. Pretreatment of nongrowing adenovirus with convalescent-phase patient serum neutralized its ability to infect the cell culture and produce fluorescent cells. Indirect immunofluorescence microscopy compared favorably with electron microscopy in demonstrating virus in the stools of patients.

Acute Disease↗
PubMed1978

Fatal rotavirus gastroenteritis: an analysis of 21 cases.

During the period of May 1972 to March 1977, twenty-one fatal cases of rotavirus acute gastroenteritis were recorded in the city of Toronto. The mean age of these subjects was approximately 1 year. Boys outnumbered girls by 12 to 9. Death occurred within three days of onset of symptoms in all cases. Sixteen of the subjects were profoundly dehydrated and had sodium levels (serum or vitreous humor) in excess of 150 mEq/liter. In 11 subjects, sodium values were greater than 160 mEq/liter. Although a physician was contacted in 16 instances, these infants still perished. We suggest that both language difficulties and the rapid rate of fluid depletion contributed significantly to the fatal outcome. At autopsy the bowel was often dilated and filled with fluid. Postmortem autolysis precluded an accurate histological assessment of the small bowel mucosa.

Acute Disease↗
PubMed1978

Lapine rotavirus: preliminary studies on epizoology and transmission.

Antibody to rotavirus was found in sera of domestic rabbits, wild cottontail rabbits and Snowshoe hares. Eight out of 187 stools from a rabbitry contained rotavirus, though no clinical symptoms were apparent. The virus extracted from one such stool infected a five week old seronegative rabbit and led to distention and congestion of the colon, excretion of virus in the stool and a serological response to virus. Human and Simian rotaviruses did not replicate in the rabbits.

Animals↗
PubMed1977

Guide to the management of rubella problems.

Despite the availability of rubella vaccine the incidence of the congenital rubella syndrome has been increasing in certain regions of Canada. Perhaps this is not surprising in view of the known irregular cyclic activity of rubella virus in a community and the fact that the percentage of seropositive women of childbearing age has not changed appreciable since the vaccine was introduced. Clearly vaccine is not being administered to sufficient numbers of women at risk. Until a much higher percentage of women of childbearing age possess rubella antibody, the costly problem of congenital rubella syndrome is likely to be with us. Common rubella problems relate to four categories: the exposed pregnant woman, laboratory diagnosis, the infant with suspected congenital rubella and the vaccine. One of the most common questions about the vaccine is the following: Can recently vaccinated individuals disseminate vaccine and infect seronegative contact? The answer is No.

Adult↗
PubMed1977

Viruses associated with acute gastroenteritis in young children.

Conventional virologic investigations generally failed to implicate viruses as a cause of acute gastroenteritis in young children. When negative-contrast stain electron microscopy was used for the examination of stool samples from affected patients, several candidate etiologic agents were discovered. Rotavirus (otherwise known as orbivirus, reo-like agent, and infantile gastroenteritis virus) emerged as an important causative agent. In a considerable number of patients, however, no causative agent was identified. Several other candidate etiologic viruses now "stand in the wings" awaiting additional evidence as to their role in the pathogenesis of acute gastroenteritis. In a study period of 12 months, 669 patients were found to be shedding virus in association with symptoms of diarrhea, vomiting, and temperature elevation. Approximately one third of these patients acquired their infection in hospital.

Acute Disease↗
PubMed1977

Solid-phase radioimmunoassay for the detection of rotavirus.

A solid-phase radioimmunoassay method has been developed for the detection of rotavirus in the form of a purified antigen and in stool. The parameters of the radioimmunoassay were examined and optimized to give high sensitivity and same-day results. Compared with electron microscopy, the assay is up to 10 times as sensitive for detection of the virus in stool and up to 128 times as sensitive for detection of a purified virus antigen. In a field study on stool specimens it was at least as efficient as electron microscopy.

Antibodies, Viral↗
PubMed1976

Viral gastroenteritis: recent progress, remaining problems.

Infants and young children are particularly susceptible to a recently identified viral enteritis which is highly contagious and seems both common and universal. In this disease, virus invades the upper intestinal epithelium, causing acute diarrhoea with early fever and vomiting. We studied a similar disease in pigs, infecting three-week-old animals with transmissible gastroenteritis virus (TGE), which also invades the upper intestinal epithelium. In this model, diarrhoea is massive 16-40 hours after infection, when stools contain increased electrolytes but no excess of sugar. In the jejunum of intact pigs at the 40-hour stage we found altered Na+ and water flux, decreased mucosal activities of disaccharidases and Na+, K+-ATPase, but normal adenylate cyclase activity. At the same stage the response of Na+ flux to glucose was blunted in jejunal epithelium studied in Ussing short-circuit chambers and in suspensions of villous cells; Cl- flux responded normally to theophylline, and thymidine kinase and sucrase activities of cells isolated from jejunal villi were similar to those found in crypt cells. Probably by 40 hours after infection most virus has been shed from the mucosa. Viral diarrhoea clearly differs from enterotoxigenic diarrhoea. Consideration of its pathogenesis must take into account the dynamic nature of the mucosal epithelium and the factors governing differentiation of enterocytes as they migrate from crypt to villus. Sufficient information is available now to characterize one specific and apparently prevalent viral enteritis in man and to identify additional viral enteritides. There is hope that preventative therapy can be developed. Our understanding of the mechanisms of viral diarrhoea is limited, but the availability of an animal model and the promise of others makes us optimistic that these deficiencies can be remedied. Greater understanding of the pathogenesis of viral diarrhoea should better the active therapy of affected infants and children.

Animals↗