Virulent and attenuated canine distemper virus infects multiple dog brain cell types in vitro.

Canine Distemper Virus (CDV) produces an encephalitis in dogs that varies with viral strain. We have studied the cell tropisms of two virulent strains (CDV-SH and CDV A75-17) and an attenuated strain, Rockborn (CDV-RO), in cultured canine brain cells. Infected cell types were identified by double immunofluorescent labeling of specific cell markers and viral antigens. All viral strains studied produced infection in astrocytes, fibroblasts, and macrophages. Neurons were not infected by CDV A75-17 but were rapidly infected by CDV-SH and CDV-RO. Multipolar oligodendrocytes were very rarely infected by any of the virus strains. In contrast, a morphologically distinct subset of bipolar oligodendrocytes were commonly infected by CDV-SH and CDV-RO. The kinetics of infection in the astrocytes, oligodendrocytes, neurons, and macrophages varied between strains. Both CDV-SH and CDV-RO rapidly infected bipolar oligodendrocytes, astrocytes, neurons, and macrophages by 14 days post infection while infection by CDV A75-17 was delayed until after 28-35 days post infection. The differences in the growth kinetics and cell tropisms for some brain cells, exhibited by the three viral strains examined in this in vitro study, may relate to the different CNS symptoms that these strains produce in vivo.     

Multivariate flow cytometric characterization and enrichment of murine megakaryocyte progenitors (CFU-Meg)

Multivariate flow cytometric analysis and sorting of mouse bone marrow cells viably stained with Hoechst 33342 (HO) was utilized to obtain a subpopulation enriched at least 30- to 60-fold for clonogenic megakaryocyte precursors (CFU-Meg). HO fluorescence intensity, forward light scatter, and perpendicular light scatter were measured on each HO-stained bone marrow cell as it passed through a dual beam flow cytometer. Cells were sorted on the basis of their light scattering and HO fluorescence intensity properties. The sorting region which included cells with high forward light scatter, low perpendicular light scatter, and low (0.1-0.65 times the modal channel) HO fluorescence intensity contained approximately 0.6% CFU-Meg. Of all CFU-Meg, 75% were contained in the light scatter gate, and 56% of all CFU-Meg were in the low HO-sorting region. This technique offers a simple, one-step procedure to obtain preparations enriched in murine clonogenic megakaryocyte precursors.     

Electrohydraulic shock wave lithotripsy (ESWL) fragmentation of retained common duct stones

Retained or recurrent stones in the common bile duct remain a clinical problem in 2% to 5% of patients undergoing cholecystectomy. Nonoperative extraction via the T tube tract or endoscopic sphincterotomy is successful in 85% to 95% of patients; however, the remainder require reoperation. This study evaluates the efficacy of electrohydraulic shock wave lithotripsy therapy of common duct stones too large to be extracted endoscopically or by T tube. Six patients were entered into the study. Ages ranged from 62 to 93 years. All patients either had severe preexisting systemic disorders or were of an advanced age. Stones ranged in size from 10 to 41 mm, with a mean largest dimension of 22 mm. In all patients either extraction by traditional nonoperative means failed or there was a stone that was considered to be too large to be extracted successfully. Patients were treated with 1200 to 2400 shocks at 16 to 20 kV. Five of six patients were treated with local anesthesia and sedation. Stones were successfully fragmented in all but one patient. Five patients required extraction of the remaining fragments either through the T tube tract (one patient) or via endoscopic sphincterotomy. All patients were free of stones at discharge, with the exception of one patient with severe cirrhosis who had an intrahepatic stone behind a right hepatic duct stricture. This stone had been successfully fragmented but an endoscopic retrograde cholangio-pancreatogram revealed some residual fragments despite normal alkaline phosphatase and bilirubin values. There were no hospital deaths, although the patient with the intrahepatic stone died of bleeding varices several months later. Electrohydraulic shock wave lithotripsy seems to be an effective adjuvant treatment in clearing the bile duct of stones that would otherwise require reoperation.     

Cognitive deficits in progressive supranuclear palsy, Parkinson's disease, and multiple system atrophy in tests sensitive to frontal lobe dysfunction.

Groups of patients with idiopathic Parkinson's disease, multiple system atrophy, and progressive supranuclear palsy or Steele-Richardson-Olszewski syndrome, matched for overall clinical disability, were compared using three computerised cognitive tests previously shown to be sensitive to frontal lobe dysfunction. On a test of planning based on the Tower of London task, all three groups were impaired, but in different ways. The groups with palsy and Parkinson's disease were slower in the measure of initial thinking time, whereas the group with multiple system atrophy was only slower in a measure of thinking time subsequent to the first move, resembling patients with frontal lobe damage. On a test of spatial working memory, each group showed deficits relative to their matched control groups, but the three groups differed in their strategy for dealing with this task. On a test of attentional set shifting, each group was again impaired, mainly at the extradimensional shifting stage, but the group with Steele-Richardson-Olszewski syndrome exhibited the greatest deficit. The results are compared with previous findings in patients with Alzheimer's disease or frontal lobe damage. It is concluded that these basal ganglia disorders share a distinctive pattern of cognitive deficits on tests of frontal lobe dysfunction, but there are differences in the exact nature of the impairments, in comparison not only with frontal lobe damage but also with one another.     

Serotonin metabolism in directly developing frog embryos during paternal care

Central serotonin (5-HT) metabolism during embryogenesis and a 3-day post-hatching period was analyzed using high performance liquid chromatography in the directly developing frog, Eleutherodactylus coqui. This anuran bypasses the free-swimming larval stage and embryos hatch as miniature frogs in the adult phenotype. During embryogenesis and for a short time immediately after hatching, male E. coqui provide paternal care by brooding and guarding eggs/embryos to prevent desiccation and predation. Serotonin and its catabolite, 5-HIAA, were measured from whole brain during embryogenesis and at 3 days post-hatch to identify critical periods in 5-HT development and to determine the relationship between 5-HT and life history events such as hatching and frog dispersal from the nest site. Serotonergic activity was highest during the early-mid embryonic stages as indicated by the ratio of 5-HIAA/5-HT, a general indicator of turnover and metabolism. There were significant increases in tissue concentrations of 5-HT during the latest or terminal embryonic stage, just prior to hatching, and also at 3 days post-hatch, shortly before neonates disperse into the rainforest. These two increases probably represent different functional requirements during development. The first may occur as a result of the surge of development in the 5-HT system during late embryogenesis that occurs in E. coqui and the second may be from the increase demand in sensory and motor neural development required before dispersal from the nest site.     

Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability

X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG repeat expansion in the first exon of the androgen receptor (AR) gene. Disease-associated alleles (37-66 CAGs) change in length when transmitted from parents to offspring, with a significantly greater tendency to shift size when inherited paternally. As transgenic mice carrying human AR cDNAs with 45 and 66 CAG repeats do not display repeat instability, we attempted to model trinucleotide repeat instability by generating transgenic mice with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions in their genomic context. Studies of independent lines of AR YAC transgenic mice with CAG 45 alleles reveal intergenerational instability at an overall rate of approximately 10%. We also find that the 45 CAG repeat tracts are significantly more unstable with maternal transmission and as the transmitting mother ages. Of all the CAG/CTG repeat transgenic mice produced to date the AR YAC CAG 45 mice are unstable with the smallest trinucleotide repeat mutations, suggesting that the length threshold for repeat instability in the mouse may be lowered by including the appropriate flanking human DNA sequences. By sequence-tagged site content analysis and long range mapping we determined that one unstable transgenic line has integrated an approximately 70 kb segment of the AR locus due to fragmentation of the AR YAC. Identification of the cis - acting elements that permit CAG tract instability and the trans -acting factors that modulate repeat instability in the AR YAC CAG 45 mice may provide insights into the molecular basis of trinucleotide repeat instability in humans.      

Five year study of prenatal testing for Huntington''s disease: demand, attitudes, and psychological assessment.

Adult predictive and prenatal testing programmes for Huntington's disease (HD) in Canada have been available since 1986. However, the demand for prenatal testing and the reasons why some people choose not to have the prenatal test for this late onset disorder have not been well documented. In addition, the knowledge and attitudes of adult predictive testing candidates and their partners about prenatal testing are not well known nor are the psychological effects of prenatal testing well understood. As of September 1991, 425 subjects had entered the Canadian Collaborative Study of Predictive Testing and, of these, 47 subjects or their partners had become pregnant. Of this group, 14 (30%) couples requested prenatal testing, 24 (51%) couples did not want prenatal testing, and nine (19%) at risk subjects had already received a decreased risk through adult predictive testing and, therefore, were not eligible for the prenatal test. Of the 14 couples who initially requested prenatal testing, seven withdrew. Thus, demand for the prenatal test by eligible candidates was 7/38 or 18%, which is much lower than the 32 to 65% expected based on early survey data. The most frequently cited reason for declining prenatal testing was the hope that a cure would be found in time for their children. While the majority of adult predictive testing candidates (71%) in our study had accurate information about definitive prenatal testing, many (63%) did not have a correct understanding of exclusion prenatal testing. Although no serious adverse events such as suicide planning or admission to psychiatric hospital have occurred, a particular need for careful counselling was identified for those at risk candidates and their partners who have one prenatal test and feel compelled to use the test again in future pregnancies. Even though prenatal testing for HD is not requested as often originally expected, it still remains a desired option for some at risk persons and their partners.     

Hepatitis A virus hemagglutination and a test for hemagglutination inhibition antibodies.

Like enteroviruses, hepatitis A virus (HAV) hemagglutinated various species of erythrocytes under similar conditions. HAV-specific antibodies in both acute- and convalescent-phase sera were found to inhibit hemagglutination. The HAV hemagglutination inhibition test can be used for diagnosis, epidemiological surveillance, and vaccine assessment.