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Featured researches published by M. Namiki.


The Journal of Urology | 1988

Surgical repair of varicocele at puberty: preventive treatment for fertility improvement.

Akihiko Okuyama; Motoyuki Nakamura; M. Namiki; Masami Takeyama; Masato Utsunomiya; Fujioka H; Hiroaki Itatani; Minoru Matsuda; Kunio Matsumoto; Takao Sonoda

In 40 pubertal boys with a varicocele a comparative followup study was performed to evaluate the efficacy of surgical correction of the varicocele in this age group in regard to improvement of fertility after completion of sexual maturation. The varicocele was corrected surgically in 24 patients and it was left uncorrected in 16. Testicular atrophy was noted in all cases at the initial visit and after followup. Of the 24 corrected patients 16 had atrophy of at least 1 testis before surgical treatment, whereas only 7 demonstrated atrophy after followup. Of the 16 uncorrected patients testicular atrophy was noted in 8 at the initial visit but 12 had atrophy after followup. Semen examination of 23 patients who had completed sexual maturation demonstrated a higher quality of routine seminal parameters, for example sperm density, sperm motility and percentage of morphologically normal spermatozoa, in the corrected group than in the uncorrected group.


Hormone Research in Paediatrics | 1996

The Y Chromosome Region Essential for Spermatogenesis

Yutaka Nakahori; Yoko Kuroki; Rie Komaki; Kondoh N; M. Namiki; Teruaki Iwamoto; Tatsushi Toda; Kazuhiro Kobayashi

We analyzed DNA from 153 Japanese men with azoospermia or severe oligozoospermia whose Y chromosomes were cytogenetically normal. A total of 23 loci on the Y chromosome were examined: 15 loci within interval 6 including YRRM1 and DAZ, and 8 loci outside interval 6. Microdeletions were observed in 20 individuals. All deletions involved at least one locus within interval 6. The YRRM1 gene deletion was found in 4 patients, of whom 2 also lacked the SMCY gene. The remaining 16 individuals shared the absence of 10 loci between DYS7C and DYS239 including the DAZ gene. Among them, 13 were azoospermic while 3 showed a little sperm production, indicating that the common deletion resulted in phenotypic diversity. Since there is no region commonly deleted in all patients, azoospermia caused by deletion of the Y chromosome long arm may be genetically heterogeneous.


Urologia Internationalis | 1987

Secondary Involvement of Genitourinary Organs in Malignant Lymphoma

Osamu Miyake; M. Namiki; Takao Sonoda; Hajime Kitamura

We examined 322 patients who had died of malignant lymphoma at our institute between 1958 and 1985 in order to study secondary involvement of genitourinary organs (GUO). Secondary involvement of GUO was more common in non-Hodgkin lymphoma (NHL) than in Hodgkins disease. The most commonly affected GUO was the kidney, which was secondarily involved in 121 out of 322 patients (37.6%). The adrenal gland was the second most commonly affected organ: 58 cases (18%) were affected by the disease and 40 of them were associated with renal involvement. Third and fourth were the urinary bladder (8.4%) and the testis (5.9%). Secondary involvement of the bladder in NHL was often accompanied with that of other GUO. Next, the relationship between metastases and histological characteristics in NHL was investigated. However, no significant correlation proved to exist between histological grade and metastases to the GUO.


Archives of Andrology | 1987

Temperature Sensitivity of Human Spermatogonia and Spermatocytes in Vitro

Motoyuki Nakamura; M. Namiki; Akihiko Okuyama; T. Matsui; Y. Doi; Masami Takeyama; Fujioka H; Yoshitake Nishimune; Keishi Matsumoto; Takao Sonoda

To study the effect of temperature on human spermatogenesis, both the number and DNA synthesis of germ cells were investigated in tissue fragments of human testes cultured for 22 h at 31 degrees C and 37 degrees C. The number of differentiated germ cells such as spermatids and spermatozoa cultured at 37 degrees C was significantly smaller than that cultured at 31 degrees C. The number of spermatogonia and resting primary spermatocytes was not significantly different between these two temperatures, but the functional ability of DNA synthesis in these cells was significantly lower at 37 degrees C than at 31 degrees C. It seems that in normal body temperature (37 degrees C) differentiated germ cells such as spermatids and spermatozoa are fragile and the DNA synthesis of spermatogonia and resting primary spermatocytes is retarded.


Human Genetics | 1992

DNA analyses of XX and XX-hypospadiac males

Hironao Numabe; Shigeo Nagafuchi; Yutaka Nakahori; Takashi Tamura; Hiromichi Kiuchi; M. Namiki; Naoya Kohda; Yoshimitsu Fukushima; Hideki Fuse; Motoyasu Kusano; Takayuki Arai; Yutaka Matsuzaki; Keiko Fukutani; Koichiro Isurugi; Yoshikazu Kuroki; Tatsuro Ikeuchi; Masahiko Yoshida; Shigeru Minowada; Yasuo Nakagome

Fourteen 46,XX “males” were analyzed by Southern blot hybridization with seventeen different Y chromosome-derived DNA probes and by the polymerase chain reaction for an additional two sites on the short arm of Y. Eight 46,XX males possessed various segments of the short arm of the Y chromosome, including the sex determining region. The detected segments ranged from the two most distal loci to nearly the entire length of the short arm, viz., 10 out of 11 loci. None of the eight patients had hypospadia. Five out of the six remaining cases had hypospadia and no Y sequence was detected, suggesting the presence of a causative difference between hypospadiac and non-hypospadiac groups.


Transplant International | 1996

Serum HGF levels in acute renal rejection after living related renal transplantation

Shingo Takada; M. Namiki; Shiro Takahara; Kiyomi Matsumiya; Kondoh N; Yukito Kokado; Kunio Matsumoto; Toshikazu Nakamura; Akihiko Okuyama

Hepatocyte growth factor (HGF), a long sought-after hepatotrophic factor, has recently been shown to act as a renotrophic factor in regeneration of the kidney. We investigated serum HGF levels in 16 renal transplant patients. In patients with acute rejection, the serum HGF level was markedly increased (over 1 ng/ml), and its elevation was accompanied by an increase in serum creatinine and blood urea nitrogen (BUN). In contrast, serum HGF levels were continuously low in patients without rejection. We conclude that serum HGF may become a clinically useful marker for the assessment of acute renal rejection.


The Journal of Urology | 1993

Significance of Subclinical Varicocele Detected by Scrotal Sonography in Male Infertility: A Preliminary Report

Kondoh N; Norio Meguro; Kiyomi Matsumiya; M. Namiki; Hisakazu Kiyohara; Akihiko Okuyama

To assess the clinical significance of subclinical right varicocele, we used scrotal sonography for a prospective study of 68 infertile patients with a clinical left varicocele. A significant difference was found in the improvement in postoperative semen characteristics between sonographically diagnosed bilateral and unilateral groups. We conclude that a subclinical right varicocele is also detrimental for spermatogenesis in patients with a clinical left varicocele.


Journal of Reproductive Immunology | 1997

Possible association of infertility with sperm-specific abnormality of CD46.

Masaya Kitamura; Kiyomi Matsumiya; Masaki Yamanaka; Siroh Takahara; Tomoko Hara; Misako Matsumoto; M. Namiki; Akihiko Okuyama; Tsukasa Seya

Three infertile patients fulfilling normal or subnormal criteria on routine semen analysis showed abnormal sperm CD46 (membrane cofactor protein of complement) by SDS-PAGE/immunoblotting analysis using a panel of monoclonal antibodies. The sperm CD46 isoform has been reported to be associated with sperm-egg interaction. These three patients expressed normal CD46 isoforms on their lymphocytes and granulocytes. Sperm-specific abnormalities in these proteins thus parallel male infertility, suggesting a new category of infertility, probably due to aberrations in the molecules related to sperm-egg interaction.


Journal of Steroid Biochemistry | 1984

Augmentation of aromatase activity by FSH in ovaries of fetal and neonatal mice in organ culture

Nobuyuki Terada; Hideya Kuroda; M. Namiki; Yukihiko Kitamura; Keishi Matsumoto

The stimulative effect of FSH on aromatase activity was investigated in ovaries of fetal (on days 17 and 18 of gestation) and neonatal mice (on days 0, 3, 6 and 9 after birth). Two to six ovaries, were cultured for 48 h in 2 ml of Medium 199 supplemented with insulin (5 micrograms/ml) and [1 alpha, 2 alpha, 6 alpha, 7 alpha, beta-3H]4-androstene-3,17-dione (0.35 microM) in the presence or absence of porcine FSH (0.5 units/ml) and the amount of [3H]oestradiol-17 beta and [3H]oestrone produced was estimated. In the presence of FSH, aromatase activity per ovary, which was found in all fetal and neonatal ovaries examined, increased with age. In the absence of FSH, however, the production of oestrogens could be demonstrated only in ovaries from 3- to 9-day old mice. FSH increased the aromatase activity by up to 10-fold. In spite of the stimulative effect of FSH on aromatase activity, FSH exerted no significant effect on DNA synthesis of the ovaries. The formation of primordial follicles could not be observed histologically in ovaries of fetal mice on day 17 of gestation, although the ovaries of 6- and 9-day old mice contained multilayered follicles. These results show that FSH stimulates the aromatase activity of the mouse ovary even before the formation of primordial follicles and that the stimulative effect of FSH on ovarian aromatase is not due to the proliferation of ovarian cells.


The Journal of Urology | 1982

Clinical Manifestations of Calcium Oxalate Monohydrate and Dihydrate Urolithiasis

Takuo Koide; Hiroaki Itatani; Toshiaki Yoshioka; Hiroshi Ito; M. Namiki; Etsuji Nakano; Akihiko Okuyama; Masato Takemoto; Takao Sonoda

We studied retrospectively 155 patients with calcium oxalate urolithiasis. The patients were divided into 3 groups: 1) those with calcium oxalate monohydrate, 2) those with calcium oxalate dihydrate and 3) those with mixed calcium oxalate monohydrate and dihydrate. Various differences were noted between patients with calcium oxalate monohydrate and those with calcium oxalate dihydrate, with respect to stone characteristics, spontaneous passage of stones, stone recurrence and multiple occurrence. Most important, we noted that patients with calcium oxalate dihydrate had more stone recurrences than patients with calcium oxalate monohydrate.

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