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Biomedical subjects

L Spence

Publications and source records attributed to L Spence.

At least 55 records · Page 3Linked to original sources
PubMed1977

Rotavirus isolation and cultivation in the presence of trypsin.

Rotaviruses are generally difficult to isolate and culture in vitro; therefore, virus isolation has not been used as a method of diagnosing this group of agents. The present report describes a simple procedure for isolating bovine rotaviruses directly from feces after pretreatment of fecal samples with trypsin. This procedure resulted in virus isolation from five of five samples that contained virus particles, as demonstrated by electron microscopy, and four of seven samples where virus particles could not be observed but were considered positive by the presence of immunofluorescent-staining cells in feces. Virus could not be isolated from "normal" feces. If the virus was not passaged in the presence of trypsin, the infectivity was gradually lost, but infectivity could be restored again if trypsin was added, resulting in increased virus spread and concomitant increase in virus yield. The application of this technique as a diagnostic tool for bovine and other rotaviruses is briefly discussed.

Cell Line↗
PubMed1977

Immune electron microscopy of arboviruses.

Representative members of four arbovirus taxons were studied by immune electron microscopy (IEM) in an attempt to determine whether the technique can be applied to the specific identification of arboviruses. Alphavirus, flavivirus, bunyavirus, and rhabdovirus antigens were prepared by propagation in tissue culture. The viruses were used to titrate homologous antibody and test heterologous antibody in the IEM test. Specific clumping together with visualization of antibody attachment was observed for all homologous systems studied. For the alphaviruses, titers of antibody, as determined by IEM, were comparable with the titers obtained by hemagglutination inhibition. Alphavirus cross-reactions were observed at low antibody dilutions by IEM. However, further dilution of antibody resulted in specific clumping only of homologous virus, allowing specific identification of alphavirus unknowns. For all viruses studied, positive IEM reactions were obtained with homologous grouping ascitic fluids but not with heterologous grouping fluids.

Antibodies, Viral↗
PubMed1976

Detection of core antibody in hepatitis B infection.

Hepatitis B core antigen (HBcAg) is found on the decoated Dane particle and on a morphologically similar particle detected mainly in the nucleus of hepatocytes of patients with hepatitis B. HBcAg prepared from the liver of a chimpanzee infected with hepatitis B virus was used to test human serum for core antibody (anti-HBc) by complement fixation. Anti-HBc was found in serum collected from patients with hepatitis B in both the acute and convalescent stages, from carriers of hepatitis B surface antigen (HBsAg) and from patients with chronic liver or renal disease who were carriers of HBsAg. It was not found in patients with hepatitis A or infectious mononucleosis, or in healthy persons who were not carriers of HBsAg.

Adult↗
PubMed1975

An outbreak of severe pneumonia due to respiratory syncytial virus in isolated Arctic populations.

A rapidly developing outbreak of pneumonia in young infants was documented in two isolated Artic populations in May 1972. These were studied virologically, serologically and clinically. In addition to the two stricken communities, one apparently unaffected with serious clinical illness and a fourth, in which are located the major hospital and airport in the eastern Arctic, were also studied. One hundred and twenty-four patients were studied serologically and 81 respiratory and other specimens were obtained for virus isolation from 40 of these patients. Clinical records were kept of the outbreak in each area and a detailed questionnaire was filled out for 140 children and their families. Respiratory syncytial irus (RSV) was cultured from eight ill children. Electron microscopy provided the first evidence of RSV infection. A seroconversion rate of approximately 50% was seen in both affected communities as well as in the clinically unaffected one. The epidemic in the first two communities was characterized by severe pneumonia and frequent hospitalization but no cases of bronchiolitis were seen. No evidence for other causes of this outbreak could be obtained by testing for antibodies to influenza A and B, parainfluenza 1, 2 and 3, adenovirus and herpes simplex viruses. Unusual features of this epidemic of RSV infection include the high attack rate, severe morbidity, illness manifest almost exclusively as pneumonia rather than bronchiolitis and the difference between the expression of disease in different communities. Historical data and clinical observations were inadequate to explain these unusual features.

Adult↗
PubMed1975

Preparation of a dane core (hepatitis B) antigen from human plasma.

Hepatitis B surface antigen (HBsAg) positive plasma, obtained from blood donors, was used to prepare an antigen (HBcAg) from the inner core of the Dane particle, the larger of the two spherical particles found in the blood in hepatitis B infection. The antigen was prepared by a series of centrifugation procedures on caesium chloride and sucrose gradients. Dane particle-rich fractions obtained from these gradients and concentrated by centrifugation were treated with Tween 80 to remove the outer coats from the particles. The remaining Dane particle cores were recovered by velocity sedimentation on a sucrose gradient. Preparations containing the Dane cores were used as antigens in the immune electron microscopy and complement fixation tests to demonstrate the specificity of HBcAg and lack of fross relationship with HBsAg. HBcAg will be used for the study of hepatitis B infections in man.

Animals↗
PubMed1973

An outbreak of adenovirus type 7 infection in children in Montreal.

Thirteen infants and children with adenovirus type 7 infection proved by virus isolation are described. High fever, cough and dyspnea were the most frequent findings; in infants under 1 year of age wheezing was common. Four patients required artificial ventilation. Lobar collapse, consolidation and hyperinflation were frequent radiologic findings. None of the symptoms responded to antibiotic therapy or bronchodilator drugs. Three patients died (mortality rate of 23%). Pathologic findings were compatible with adenovirus type 7 pneumonia, and were characterized by a necrotizing bronchitis and bronchiolitis, patchy alveolar fibrinopurulent exudate and hyaline membrane formation. Some intra-alveolar epithelial cells showed strikingly abnormal nuclei and rare typical halo-outlined intranuclear inclusions were seen. Only one of eight survivors had evidence of significant chronic chest disease.

Adenoviridae Infections↗
PubMed1973

Hepatitis with Australia antigenemia following renal transplantation.

Over a seven-year period 18 of 125 patients who underwent renal transplantation developed hepatitis. Acute hepatic necrosis occurred in two, chronic aggressive hepatitis progressing to posthepatitic cirrhosis in eight, chronic persistent hepatitis in five, acute hepatitis with recovery in two and cholestatic hepatitis in one. Hepatic failure was the cause of death in four and a major contributing factor in three. Fifteen of the 18 were of blood Group A. After renal transplantation Australia antigen (Au) was present in the blood of 12 of the 15 patients with hepatitis who were tested and in one of 38 patients without clinical evidence of liver disease. Once present, Au persisted in all patients but one. Particles measuring 210 to 250 A, characteristic of Au, were seen in liver cells by electronmicroscopy in nine of the 10 patients examined who had hepatitis with Australia antigenemia, but they were not seen in the two patients studied with Au-negative hepatitis.

Acute Disease↗
PubMed1971

Aseptic meningitis, Montreal, 1969: a clinical and laboratory study.

During the summer and fall of 1969 an outbreak of aseptic meningitis occurred in Montreal and its environs. Forty-four patients were admitted to the infectious disease ward of The Montreal Children's Hospital in August, September and October. Half of the patients were in the age group 6 to 10 years. The ratio of males to females was two to one. Patients showed the typical signs and symptoms of aseptic meningitis, namely fever, vomiting, headache, neck stiffness and pleocytosis of the cerebrospinal fluid.Viruses were recovered from 19 (43%) of the 44 cases. The predominant virus in the outbreak was a non-hemagglutinating strain of echovirus 6. Other virus types isolated in the outbreak were echovirus 7, coxsackievirus A9 and coxsackievirus B4. Serological investigations confirmed the validity of the echovirus isolations and identified additional cases.

Age Factors↗