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Biomedical subjects

R Yanagihara

Publications and source records attributed to R Yanagihara.

At least 163 records · Page 9Linked to original sources
PubMed1985

Serological evidence of Hantaan virus infection in the United States.

We found low titers of fluorescent antibodies against Hantaan virus, the etiologic agent of Korean hemorrhagic fever, in sera from 7 of 1,035 patients with febrile illnesses of unknown origin and from 6 of 664 blood donors in the United States. All but 1 of these individuals possessed neutralizing antibodies against Hantaan virus. This was a 31-year-old research technician who had worked with laboratory rodents with virus-induced tumors, but had not traveled abroad, suggesting that infection with Hantaan virus or a closely related agent was locally acquired. However, the precise source of his infection remains unclear.

Adult↗
PubMed1984

Cortical bone loss and measurements of the second metacarpal bone: II. Hypodense bone in postwar Guamanian children.

Hand-wrist radiographs from 326 Guamanian children (180 boys and 146 girls) were evaluated for total width, medullary width, length, and combined cortical thickness of the second metacarpal. Bone measurements as well as standing height and weight were compared to similar published data from U.S. mainland black, white, and Mexican-American children. The results demonstrated that the second metacarpal bones of Guamanian boys and girls of all age groups (5-17 years) have narrower width and shorter length with less combined cortical thickness than any of the other groups. Guamanian children also weighed less and were of shorter stature than their black, white, or Mexican-American counterparts. These results agree closely with those comparisons between Guamanian and U.S. mainland white adults published earlier. It is not possible from the present data to ascertain whether these differences were due to genetic variability or nutritional deficiency.

Adolescent↗
PubMed1984

Calcium and vitamin D metabolism in Guamanian Chamorros with amyotrophic lateral sclerosis and parkinsonism-dementia.

We evaluated 16 Guamanian Chamorros with amyotrophic lateral sclerosis and 33 patients with parkinsonism-dementia for disturbances of calcium and vitamin D metabolism. The serum immunoreactive parathyroid hormone level was mildly elevated in 6 patients with amyotrophic lateral sclerosis and in 5 patients with parkinsonism-dementia. There were significant positive correlations between serum immunoreactive parathyroid levels and duration of illness in male patients with motor neuron disease, but not in female patients or in patients with parkinsonism-dementia. Intestinal absorption of calcium, as assessed by serum and urinary activity of calcium 47 following oral administration, was decreased in 2 patients with amyotrophic lateral sclerosis and in 4 patients with parkinsonism-dementia, all of whom had low levels of serum 1,25-dihydroxyvitamin D. Reductions in cortical bone mass were striking in patients with motor neuron disease. A significant negative correlation was found between the percentage of cortical area of the second metacarpal bone and muscle atrophy and weakness, and significant positive correlations were found between degree of immobility and ratio of urinary hydroxyproline to creatinine in patients with amyotrophic lateral sclerosis and parkinsonism-dementia. In general, abnormalities in calcium metabolism were subtle. Thus, if the demonstrated deposition of metals, particularly calcium and aluminum, in central nervous system tissues of Guamanians with these two conditions is a cause of the diseases and of the early appearance of neurofibrillary tangles in neurons, the accumulation has apparently occurred long before onset of symptoms, and detectable abnormalities of calcium and vitamin D metabolism may already have been corrected.

Adult↗
PubMed1984

Imaging of calcium and aluminum in neurofibrillary tangle-bearing neurons in parkinsonism-dementia of Guam.

We report the distribution and imaging of calcium and aluminum in neurofibrillary tangle (NFT)-bearing neurons within Sommer's sector of the hippocampus in Guamanian patients with parkinsonism-dementia, using a method of computer-controlled electron beam x-ray micro-analysis and wavelength dispersive spectrometry. Calcium and aluminum were distributed in cell bodies and axonal processes of NFT-bearing neurons. The elemental images show that both calcium and aluminum deposits occur within the same NFT-bearing hippocampal neuron in this dementing disease, suggesting that these elements are involved in NFT formation. No prominent concentrations of calcium and aluminum were imaged in non-NFT-containing regions within the pyramidal cell layer of the parkinsonism-dementia cases or in the control cases. These findings support the hypothesis that secondary hyperparathyroidism resulting from low environmental calcium and magnesium in the high-incidence focus of amyotrophic lateral sclerosis and parkinsonism-dementia on Guam had led to abnormal deposition of calcium and aluminum in the central nervous system.

Aged↗
PubMed1984

Isolation and propagation of nephropathia epidemica virus in bank voles.

Three strains of nephropathia epidemica (NE) virus were isolated from lung tissues of bank voles (Clethrionomys glareolus) and a grey-sided vole (C. rufocanus) trapped in Västerbotten county, Sweden. Two of these isolates were serially passaged in seronegative laboratory-bred bank voles. Experimentally infected animals developed a subclinical infection characterized by virus persistence, particularly in lung tissue. Attempts to infect other species of colonized rodents with NE virus and to isolate NE virus from acute phase patient blood were unsuccessful. The serial propagation of NE virus in colonized bank voles provides opportunities to study experimental infection in its reservoir rodent host.

Animals↗
PubMed1980

Secretory immunological response in infants and children to parainfluenza virus types 1 and 2.

The secretory immunological responses to natural infection with parainfluenza viruses ae not well defined. Nasopharyngeal secretion specimens from 20 infants and children naturally infected with parainfluenza virus type 1 or type 2 were examined for class-specific antibody and virus-neutralizing activity. There was a marked discordance in individual secretions between immunoglobulin A (IgA) antibody (as measured by indirect immunofluorescence) and neutralizing activity (as determined by either hemadsorption plaque or 50% tissue culture infective dose reduction) to the infecting parainfluenza virus type. Many secretions contained neutralizing activity in the absence of detectable IgA antibody; conversely, secretions with measureable IgA antibody frequently lacked neutralizing activity. Moreover, there was no relationship between neutralizing activity and the course of illness. All 11 patients with serial secretion specimens showed a fourfold or greater titer rise in IgA antibody to the homologous parainfluenza virus type. Antibody usually appeared 7 to 10 days after the onset of symptoms and peaked at about 2 weeks. This response did not appear to be related to age or to severity of illness. in general, the secretory responses resembled those seen in infants infected with respiratory syncytial virus.

Antibodies, Heterophile↗
PubMed1980

Cryopreservation of virus-infected cells for use in the fluorescent antibody to membrane antigen test.

Tissue culture cells infected with varicella-zoster, respiratory syncytial, para-influenza types 1, 2, and 3, and influenza A/Texas/1/77 and A/USSR/90/77 viruses were exposed to ultraviolet light and frozen in the presence of a final concentration of 20% glycerol. These cells were quick thawed at 37 degrees C and compared with freshly prepared, living infected tissue culture cells in assays of fluorescence antibodies to membrane antigens of the infecting agents in serum, nasal wash secretions, colostrum, and breast milk. Frozen cells performed as efficiently as fresh cells as targets and retained their activity for long periods of time. Cryopreservation combined with photoinactivation of infected target cells allows this useful antibody test to be performed in routine serology laboratories.

Antigens, Viral↗
PubMed1977

Treatment of systemic lupus erythematosus with the T-cell immunopotentiator levamisole: a follow-up report of 16 patients under treatment for a minimum period of four months.

Treatment of 16 SLE patients with levamisole resulted in significant reduction of a variety of clinical parameters of the disease. Clinical improvement was both subjective and objective. Thus, levamisole may represent a possible alternative or adjunctive approach to SLE therapy. Although proper assessment of its actual quantitative importance in the treatment of Lupus must await large scale studies under double-blind conditions, nevertheless, these preliminary results are very encouraging.

Antibodies, Antinuclear↗
PubMedDate not supplied

Genetic and phylogenetic analyses of human T-cell lymphotropic virus type I variants from Melanesians with and without spastic myelopathy.

Molecular variants of human T-cell lymphotropic virus type I (HTLV-I) have been isolated recently from lifelong residents of remote Melanesian populations, including a Solomon Islander with tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM) or HTLV-I myeloneuropathy. To clarify the genetic heterogeneity and molecular epidemiology of disease-associated strains of HTLV-I, we enzymatically amplified, then directly sequenced representative regions of the gag, pol, env, and pX genes of HTLV-I strains from Melanesians with and without TSP/HAM, and aligned and compared these sequences with those of HTLV-I strains from patients with TSP/HAM or adult T-cell leukemia/lymphoma and from asymptomatic carriers from widely separated and culturally disparate populations. Overall, the HTLV-I variant from the Solomon Islander with TSP/HAM, like HTLV-I strains from asymptomatically infected Melanesians, diverged by approx 7% from cosmopolitan HTLV-I strain. No disease-specific viral sequences were found. Gene phylogenies, as determined by the unweighted pair-group method of assortment and by the maximum parsimony method, indicated that the Melanesian and cosmopolitan strains of HTLV-I have evolved along separate geographically dependent lineages, one comprised of HTLV-I strains from Papua New Guinea and the Solomon Islands, and the other composed of virus strains from Japan, India, the Caribbean, Polynesia, the Americas, and Africa. The total absence of nonhuman primates in Papua New Guinea and the Solomon Islands precludes any possibility that the Melanesian HTLV-I strains have evolved recently from the simian homolog of HTLV-I.

Adult↗
PubMedDate not supplied

Establishment and characterization of 13 cell lines from a green turtle (Chelonia mydas) with fibropapillomas.

Thirteen cell lines were established and characterized from brain, kidney, lung, spleen, heart, liver, gall bladder, urinary bladder, pancreas, testis, skin, and periorbital and tumor tissues of an immature male green turtle (Chelonia mydas) with fibropapillomas. Cell lines were optimally maintained at 30 degrees C in RPMI 1640 medium supplemented with 10% fetal bovine serum. Propagation of the turtle cell lines was serum dependent, and plating efficiencies ranged from 13 to 37%. The cell lines, which have been subcultivated more than 20 times, had a doubling time of approximately 30 to 36 h. When tested for their sensitivity to several fish viruses, most of the cell lines were susceptible to a rhabdovirus, spring viremia carp virus, but refractory to channel catfish virus (a herpesvirus), infectious pancreatic necrosis virus (a birnavirus), and two other fish rhabdoviruses, infectious hematopoietic necrosis virus and viral hemorrhagic septicemia virus. During in vitro subcultivation, tumor-like cell aggregates appeared in cell lines derived from lungs, testis, and periorbital and tumor tissues, and small, naked intranuclear virus particles were detected by thin-section electron microscopy. These cell lines are currently being used in attempts to isolate the putative etiologic virus of green turtle fibropapilloma.

Animals↗
PubMedDate not supplied

Hantavirus infections in humans and commensal rodents in Singapore.

To determine the extent of hantavirus infection in Singapore, serological studies using the indirect immunofluorescent antibody (IFA) test were conducted on commensal rodents and on human patients in 4 diagnostic groups. Virus isolation using a Vero E6 cell line was performed on hantaviral antigen-positive rodent lung tissue. Of 142 rodents and 3 insectivores studied, 37 (26%) were seropositive for IFA. Rattus norvegicus was the predominant species captured, with the highest species-specific seropositive rate of 32% (36 of 113). A hantavirus strain, R36, was isolated from one R. norvegicus. Seropositive rates for human patients were: 8% respectively for dengue haemorrhagic fever suspects and for non-A non-B hepatitis patients, 3% for leptospirosis suspects and 2% for acute nephritis patients. 2 patients had marked liver dysfunction but mild renal involvement. This hepatitis-like manifestation appears to be a clinical variant of hantavirus infection.

Adult↗