Biomedical subjects

Machiko Arita

Publications and source records attributed to Machiko Arita.

7 recordsLinked to original sources

PubMed2006

A mouse model for Stickler's syndrome: ocular phenotype of mice carrying a targeted heterozygous inactivation of type II (pro)collagen gene (Col2a1).

The influences of targeted heterozygous inactivation of type II (pro)collagen gene (Col2a1) on eye structures in the 15-month-old C57BL/6JOlaHsd mouse was studied. The eyes were collected from C57BL mice heterozygous for a targeted inactivation of one allele of the Col2a1 gene (Col2a1(+/-) mice). The eyes of C57BL mice with normal gene alleles were used as controls (Col2a1(+/+) mice). Ocular histology was analyzed from tissue sections, stained with hematoxylin and eosin, toluidine blue and alcian blue. Type II collagen was localized by immunohistochemistry. Hyaluronan (HA) was stained utilizing the biotinylated complex of the hyaluronan-binding region of aggrecan and link protein (bHABC). The anterior segment of the eye was well-formed in both genotypes, but typical folding of ciliary processes was decreased, while increased stromal extracellular matrix vacuolization was seen in the Col2a1(+/-) mice. In the lens of these mice, subcapsular extracellular matrix changes were observed. Differences in retinal structures or the number of the eyes with retinal detachment were not detected between the genotypes. In Col2a1(+/-) mice, staining for type II collagen was weaker in cornea, ciliary body, iris, lens, vitreous, retina, choroid and sclera than in the control mice. HA staining was detected in the extraocular tissues, ciliary body, iris and the choroid of both genotypes. HA staining was observed only in the vitreous body of the control animals. Heterozygous inactivation of Col2a1 gene causes structural defects in the murine eye. The observed structural changes in the ciliary body, lens and vitreous of the Col2a1(+/-) mice may represent ocular features found in the human Stickler syndrome, where the abnormalities result from COL2A1 gene mutations which lead to functional haploinsufficiency.

Aggrecans↗

PubMed2004

A human COL2A1 gene with an Arg519Cys mutation causes osteochondrodysplasia in transgenic mice.

OBJECTIVE: An arginine-to-cysteine substitution at position 519 of the COL2A1 gene causes early generalized osteoarthritis with mild chondrodysplasia in humans. In this study, a human COL2A1 gene with the same mutation was introduced into a murine genome having 1 or no alleles of the murine Col2a1 gene, and the skeletal phenotypes of the transgenic mice were compared with those of control mice. METHODS: Mice with 1 allele of the normal murine Col2a1 gene and 1 allele of the mutated human COL2A1 gene (n = 10), those with no murine Col2a1 gene and 2 alleles of the mutated human COL2A1 gene (n = 13), those with no murine Col2a1 gene and only 1 allele of the mutated COL2A1 gene (n = 9), and normal control mice (n = 11) were studied for skeletal abnormalities, using radiographic imaging and light microscopic analyses of histologic sections. The collagen network of cartilage was also investigated with transmission electron microscopy. RESULTS: At 2 months of age, all transgenic mice had dysplastic changes in their long bones, flattened vertebral bodies, and osteoarthritic changes in their joints. The intervertebral discs of the transgenic animals were degenerated, and their histologic structure was disturbed. The changes were more severe in mice with no murine Col2a1 allele. CONCLUSION: The human COL2A1 gene with the Arg519Cys mutation causes osteochondrodysplasia in mice, as it does in humans.

Alleles↗

PubMed2004

A 3-year prospective study of a urinary antigen-detection test for Streptococcus pneumoniae in community-acquired pneumonia: utility and clinical impact on the reported etiology.

To evaluate the efficacy of a rapid immunochromatographic membrane test (ICT) for the detection of Streptococcus pneumoniae urinary antigen for diagnosing S. pneumoniae pneumonia, ICT was performed with urine samples using the Binax NOW Streptococcus pneumoniae kit at the time of admission. The results were compared with those from conventional microbiological studies. Three hundred and forty-nine adult patients with CAP who were admitted to the hospital were studied prospectively between February 2001 and January 2004. The ICT test was positive in 115 (33.0%) of 349 patients enrolled into the study and in 63 (75.9%) of 83 patients with pneumococcal pneumonia confirmed by conventional methods. The test revealed a sensitivity of 75.9% and a specificity of 94.0% with conventional microbiological criteria used as the reference standard. The positive predictive value was 91.3%, and the negative predictive value was 82.6%. The clinical features of 53 patients in whom ICT was positive and no pathogen was identified showed no significant difference from those of 83 patients who had pneumococcal pneumonia identified by conventional methods. The diagnostic yield of pneumococcal pneumonia was increased up to 38.9% using ICT combined with conventional methods. The Binax NOW ICT to detect S. pneumoniae urinary antigen is therefore a rapid and useful method for diagnosing pneumococcal pneumonia. Induction of ICT will prove the predominance of S. pneumoniae in the etiology of CAP.

Adolescent↗

PubMed2002

Hyper-IgM syndrome with systemic tuberculosis.

A 33-y-old man with Hyper-IgM syndrome developed a severe tuberculous disease complicated by pleuritis and spondylitis. An abnormally decreased CD4/CD8 ratio, decreased CD4 + T-cell count and depressed natural killer cell activity implicated a coexistent cell-mediated immunodeficiency. To our knowledge, this is the first detailed report of tuberculosis associated with Hyper-IgM syndrome.

Adult↗

PubMed2002

[An autopsied case of septicemia due to Vibrio vulnificus].

A 63-year-old male with liver cirrhosis due to type-C hepatitis virus was admitted on June 14, 1999 to our hospital with complaints of dyspnea, and blisters, swelling and purpuras on his legs. He had consumed raw fish one or two days before. He was already in a state of shock with sepsis and disseminated intravascular coagulation shortly after the admission. Although treatment with MEPM and MINO for sepsis, and daltepalin sodium, antithrombin III and gabexate mesilate for disseminated intravascular coagulation was begun within 12 hours, he died only 30 hours after admission. The causative organism was detected from the blood and the contents of blisters, and was determined as Vibrio vulnificus. On autopsy, Vibrio vulnificus was also detected from skin and muscular tissue of his legs, but necrotizing fasciitis were not apparently revealed. Coagulating necrosis and acute tubular necrosis were verified in intestine and kidneys respectively probably due to ischemic changes. Pseudolobuli were formed and a small hepatocellular carcinoma was detected in the liver. Vibrio vulnificus has two infection channels; one is oral intake and the other is an external wound. The former is said to become serious. It has a rather short period from the starting of the symptom to death, and is highly fatal. If this bacteria is suspected by the clinical coarse of the patients or the laboratory examinations, it is necessary to dose effective antibiotics in its early stage. And for prevention, susceptible patients must be informed of the existence of this disease and the necessity of adequately heating raw seafood.

Bacteremia↗

PubMed2002

Familial cases of psittacosis: possible person-to-person transmission.

A 29-year-old woman with primary myelofibrosis developed severe pneumonia, and 20 days later her 31-year-old sister also contracted pneumonia. The first patient had been in contact with parakeets but the second patient had not been in contact with any birds. Psittacosis was diagnosed in both cases by microplate immunofluorescence antibody technique. Person-to-person transmission between the sisters was suspected to have taken place.

Adult↗

PubMed2002

[Evaluation of community-acquired pneumonia guidelines of Japanese Respiratory Society: differentiation of atypical pneumonia and bacterial pneumonia].

To evaluate the usefulness of differentiation of atypical pneumonia and bacterial pneumonia in the community-acquired pneumonia guidelines of the Japanese Respiratory Society, we investigated 124 cases of three atypical pneumonias (Mycoplasma pneumonia, 62 cases; Chlamydia pneumoniae pneumonia, 46 cases; Chlamydia psittaci pneumonia, 13 cases) and 403 cases of bacterial pneumonia at our hospital over seven years. Overall, the sensitivity and specificity of the criteria in the guideline were 70.4% and 91.8%, respectively. High accordance was recognized in patients under 60 years old with atypical pneumonia. Items in the criteria that included subjective factors were considered inassessable. We found that the differentiation of pneumonias in the guideline is useful for the diagnosis of atypical pneumonia among younger patients, but it should be concise and objective. We therefore propose that the criteria would be more effective if they consisted of only 4 items: age under 60 years, no underlying disorders, presence of stubborn dry cough, and normal peripheral white blood cell count.

Adolescent↗