Biomedical subjects

M Yao

Publications and source records attributed to M Yao.

At least 199 records · Page 11Linked to original sources

PubMed1993

Mapping the Von Hippel-Lindau disease tumour suppressor gene: identification of germline deletions by pulsed field gel electrophoresis.

Von Hippel-Lindau (VHL) disease is a dominantly inherited familial cancer syndrome in which affected individuals have a greatly increased predisposition to the development of haemangioblastomas of the central nervous system and retina, renal cell carcinoma and phaeochromocytoma. The VHL gene has been mapped to chromosome 3p25-p26 by genetic linkage studies and we have previously demonstrated that the VHL gene is tightly linked to the D3S601 locus (Zmax = 18.86 at theta = 0.0) suggesting that D3S601 maps close to the VHL disease gene. We have constructed a long range physical map around D3S601 and screened 91 VHL patients from 80 kindreds for germline rearrangements using pulsed field gel electrophoresis. Two patients showed abnormal fragments in Mlul digested DNA probed with D3S601. Further analysis was consistent with both patients having germline deletions (approximately 120 kb and 50 kb) telomeric to D3S601. These results have (i) established the position of the VHL disease gene with respect to D3S601, (ii) refined the localisation of the VHL disease gene to a small region (approximately 50 kb) of chromosome 3p25-p26 and (iii) excluded the plasma membrane Ca(+)+-transporting ATPase isoform 2 (PMCA-2) gene as a candidate gene for VHL disease.

Chromosome Mapping↗

PubMed1993

[New salvage chemotherapy (cisplatin, adriamycin, bleomycin, methotrexate, etoposide) for advanced nonseminomatous testicular cancer: experience in three cases].

Three patients with advanced non-seminomatous testicular tumor were treated with a new salvage chemotherapy. All patients were refractory to prior PVB (cisplatinum, vinblastine, bleomycin) or VAB-6 (cisplatinum, bleomycin, vinblastine, dactinomycin, cyclophosphamide) therapy. They were treated with the following combination chemotherapy: Cisplatin 30 mg/body day 1-5; adriamycin 40 mg/body day 1; bleomycin 30 mg/body/day 1: methotrexate 400 mg/body day 1; etoposide 150 mg/body day 1-5 (CABME therapy). This treatment was repeated monthly and in total four courses were given. One complete response and one partial response were obtained. Especially, we achieved 65% and 63% remission of liver metastases and residual tumors could be resected. Myelosuppression was marked, but other toxicity was tolerable. Therefore, we postulated that CABME therapy played an important role for the refractory testicular tumors.

Adult↗

PubMed1993

[Clinical observations on bladder cancer--difference in clinical features with age].

Three hundred and ninety-four patients with transitional cell carcinoma of the bladder who initially visited Yokohama City University Hospital were reviewed according to age group. The patients were divided into four groups, group A (less than 49 years old), group B (from 50 to 64 years old), group C (from 65 to 79 years old) and group D (more than 80 years old). The clinical characteristics as follows were obtained by statistical analysis compared with these four groups. No statistical significance was obtained about frequency of macroscopic hematuria as chief complaint. However, the younger age groups (A and B) tended to visit hospital later after the first symptom of hematuria. The older age groups (C and D) had multiple and large tumor at the first cystoscopic examination. The older age groups (C and D) had high stage and high grade tumor at the first roentgenological examination and transurethral biopsy or resection. The 5-year recurrence free rate after transurethral resection of bladder tumor (TUR-BT) of the older age group (D group) was lower than that of the other groups. The 5-year survival rate of older age group was lower than that of the younger age group. However, no statistical significance between the age groups existed concerning high grade or high stage tumor and survival after total cystectomy. We clarified here that the clinical features of elderly patients who have bladder cancer were significantly different from those of younger patients. Otherwise the prognosis of patients who have high grade and/or high stage bladder cancer were demonstrated to be poor regardless of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Magnetic resonance imaging in preoperative localization of diseased parathyroid glands: a comparison with isotope scanning and ultrasonography.

The value of magnetic resonance imaging (MRI) in the preoperative localization of parathyroid glands was assessed through a comparison of the findings with those obtained by ultrasonography and isotope scanning. The localization findings in 37 patients with primary hyperparathyroidism were compared with the operative findings. The sensitivities of the three modalities as defined by the ability to detect a parathyroid adenoma were 67% (isotope scanning), 44% (ultrasonography) and 36% (MRI). The differences were not significant. The sensitivities as defined by the ability to predict the correct side of the lesion were 48% (isotope scanning) 33% (ultrasonography) and 36% (MRI). No correlation was found between the sensitivity of a given localization test and factors such as the presence of thyroid abnormalities, size of the lesion, type of lesion and preoperative calcium and parathormone levels. The low sensitivity and high cost of all three preoperative localization studies render them unnecessary in the management of uncomplicated parathyroid disease. However, if preoperative imaging is necessary, ultrasonography and isotope scanning are recommended, since MRI was not found to be superior.

Adult↗

PubMed1992

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↗

PubMed1992

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↗

PubMed1992