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Biomedical subjects

M Yao

Publications and source records attributed to M Yao.

At least 19 recordsLinked to original sources

Screening for von Hippel-Lindau disease by DNA polymorphism analysis.

OBJECTIVE: Von Hippel-Lindau (VHL) disease is a rare, inherited multisystem neoplastic disorder. There is no biochemical test available to distinguish VHL disease gene carriers from their healthy siblings. We evaluated DNA polymorphism analysis as a method for identifying disease gene carriers. DESIGN: Prospective comparison of the results of DNA analysis with a comprehensive clinical screening examination. SETTING: The Clinical Center of the National Institutes of Health. PATIENTS: Blood was collected from 182 members of 16 families with VHL disease. Forty-eight asymptomatic individuals, at risk of developing this hereditary illness (with an affected parent or sibling), were examined for occult disease at the Clinical Center of the National Institutes of Health and tested by DNA polymorphism analysis. RESULTS: DNA polymorphism analysis predicted nine disease gene carriers and 33 individuals with the wild-type (normal) allele among the 48 individuals at risk of developing VHL disease; the test was not informative in six individuals. All nine individuals predicted to carry the VHL gene had evidence of occult disease on clinical examination. There was no clinical evidence of VHL disease in 32 of 33 individuals predicted to carry the wild-type allele. CONCLUSIONS: DNA polymorphism analysis can identify individuals likely to carry the VHL disease gene among asymptomatic members of disease families. This technique serves to focus attention on those individuals who require periodic medical examination and may help to alleviate the morbidity and mortality associated with this disease.

DNA

Crystallization and preliminary X-ray structure analysis of pigeon egg-white lysozyme.

Calcium binding lysozyme from pigeon egg-white was crystallized by the hanging drop vapor diffusion technique using ammonium sulphate as a precipitant. The crystals belong to the orthorhombic system, space group P2(1)2(1)2(1), and have unit cell dimensions of a = 34.2 A, b = 34.8 A, and c = 99.4 A. One asymmetric unit contains one molecule of the pigeon lysozyme. The crystals diffract X-rays at least to 2.0 A resolution and are suitable for high resolution structure analysis. The diffraction data up to 3.0 A resolution were collected with a diffraction image processor, DIP100, using a Fuji imaging plate as an area detector. The structure was solved by the molecular replacement technique and refined to an R factor of 0.216. Least-squares fitting of the main-chains of pigeon egg-white lysozyme with those of chicken egg-white lysozyme and baboon alpha-lactalbumin showed that the main-chain folding of pigeon lysozyme is more similar to that of chicken lysozyme than that of alpha-lactalbumin. The largest differences between the pigeon and chicken lysozymes are in the surface loop regions.

Amino Acid Sequence

[Study of c-myc gene transfected T-24 human bladder cancer cells].

To investigate the roll of c-myc protooncogene in human bladder cancer, c-myc gene was transfected into T-24 human bladder cancer cells and the changes of cell characteristics were studied. C-myc gene transfection was performed, using the electroporation method described previously (J.J. Urology, 80, 1989). After electroporation, c-myc gene was transfected and neo cells were cloned in a neomycin containing medium. One typical cloned cell (myc-cl3) was obtained. And this cell clone was shown to contain more than 3 extra-copies of c-myc gene by Southern blotting analysis. Morphology and growth speed of the myc-cl3 cells were not significantly different from those of original T-24 cells. However, they easily made overlapped cell-layers in the confluent growth phase. In the soft-agarose semi-solid medium, myc-cl3 cells formed about 35 times more numerous colonies than T-24 cells. Myc-cl3 cells also formed tumors on nude-mice at a significantly higher rate than T-24 cells did. These results suggest that c-myc gene plays a key roll in clonal growth and tumor formation in human bladder cancer.

Animals

[Pyeloureteritis cystica diagnosed by using a ureteroscope: a case report].

We report a case diagnosed as pyeloureteritis cystica by ureteroscopic examination. A 70-year-old female was admitted to our hospital with microhematuria. Intravenous pyelography and retrograde pyelography demonstrated multiple filling defects in bilateral renal pelvis and ureters. Urinary cytology findings indicated class III on both side. Ureteroscope and cold cup biopsy were performed, and histological examination revealed chronic ureteritis. Forty-four Japanese cases including our case are herein reviewed.

Aged

[Carcinoma of the urinary bladder in a patient receiving cyclophosphamide for Wegener's granuloma: a case report].

We present a case report of cyclophosphamide-induced bladder tumor. The patient is a 31-year old male who had received 240 g of cyclophosphamide for 8 years because of the therapy for Wegener's granuloma. Transurethral resection of bladder tumor was performed and transitional cell carcinoma pT1G2 ascertained by histological examination. Forty-three foreign cases and nine Japanese cases including our case are herein reviewed.

Adult