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Biomedical subjects

H A Spence

Publications and source records attributed to H A Spence.

8 recordsLinked to original sources
PubMed1994

The effect of influenza C virus on the Purkinje cells of chick embryo cerebellum.

Intra-amniotic inoculation of influenza C virus resulted in observable and quantitatively measurable changes in the Purkinje cells of chick embryo cerebellum. Purkinje cells were visualized by the Golgi-Cox procedure and prepared for statistical and computer evaluation from camera lucida drawings. Four computer-generated measurements (the area of the dendritic arbor, the perimeter of the dendritic tree, and the height and width of the cell's arborization) and two manually counted measurements (total number of branches and the number of first order branches) were made. Analysis of Purkinje cells from influenza C virus-infected embryos showed disturbances in dendritic arborization patterns and misalignment in the arrangement of the cells in the Purkinje cell layer compared to control cells. Statistical evaluation of Purkinje cell arborization showed significant decreases in all measured parameters for the influenza C virus-infected members when compared with the members of the uninfected control group.

Animals↗
PubMed1989

Detection of influenza C virus by using an in situ esterase assay.

A variety of chemically defined compounds were tested to characterize the substrate specificity of the influenza C virus esterase and to determine whether a substrate could be found that would be useful in an assay to detect the virus. Two new substrates, alpha-naphthyl acetate and alpha-naphthyl propionate, were identified; alpha-naphthyl acetate was employed to develop an assay specific for influenza type C virus in MDCK cells. The assay was sufficiently sensitive to detect esterase activity in a single cell and distinguished influenza C virus infections from those of types A and B viruses. Infected cells could be detected as early as 8 h postinfection, with maximal enzyme detection occurring at 24 h. Assay of influenza C virus in the chorioallantoic or amniotic fluid of infected eggs was performed by applying fluids directly onto nitrocellulose strips and then incubating with alpha-naphthyl acetate. Both the cellular and nitrocellulose-bound assays are rapid, inexpensive, and easy to perform, offering advantages for use in clinical laboratories.

Animals↗
PubMed1985

Induction of chick embryo feather malformations by an influenza C virus.

The effect of influenza C virus, strain JJ/50, on the development of chicken embryos infected at 10 or 12 days was documented by microscopic techniques, as well as by gross observations of embryos or chicks at hatching. The infected, newly hatched chicks displayed marked abnormalities in their feathering. Such abnormalities were observed neither in mock-infected embryos nor in embryos injected with virus which had been previously treated with specific influenza C virus antibody. At a microscopic level, the abnormalities apparently are a result of hypertrophy and/or hyperplasia of the developing barb and barbule cells. Further, the additional development of integumental necrotic foci was correlated with the development of relatively high viral titers (greater than 256) as measured by hemagglutination (HA). Embryos infected after 12 instead of 10 days incubation showed normal feathering at hatching. Infection at 12 days, however, was correlated with the development of relatively low viral titers (HA = 4) and limited degeneration of the respiratory epithelium. The relationship of teratogenic effects to the site of viral replication in rapidly differentiating tissue is discussed.

Animals↗
PubMed1978

Credentialing in the clinical laboratory sciences.

There are essentially two types of credentialing. One recognizes the competence of educational programs to prepare personnel and is generally referred to as accreditation. The second recognizes the competence of individuals to deliver services and includes the processes of certification, licensure, and registration.

Accreditation↗