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Biomedical subjects

A Imai

Publications and source records attributed to A Imai.

At least 55 records · Page 3Linked to original sources
PubMed2000

Differential efficacy of gonadotropin-releasing hormone (GnRH) agonist treatment on pedunculated and degenerated myomas: a retrospective study of 630 women.

This study was designed to compare the anatomical location of myomas (submucous, intramural, subserous, or cervical), whether pedunculated or non-pedunculated if degenerated or undegenerated and relating these findings to myoma volume reduction in women treated with gonadotropin-releasing hormone agonist (GnRHa). Our retrospective study group included 630 patients with symptoms attributed to fibroids. They were treated with a single GnRH agonist for 20 weeks and the size of the myoma was monitored by magnetic resonance imaging and/or ultrasonographic scan. During a 20 week-treatment, submucous, intramural, or subserous fibroids showed an overall reduction of 63% (P<0.01) with little variation between these types. No reduction in size was seen in cases of pedunculated, degenerated, or cervical myomas. These data suggest that GnRH agonist therapy might be used primarily for non-pedunculated and undegenerated myomas.

Journal Article↗
PubMed2000

A gonadotropin-releasing hormone-responsive phosphatase hydrolyses lysophosphatidic acid within the plasma membrane of ovarian cancer cells.

Lysophosphatidic acid (LPA) mediates pleomorphic effects on multiple cell lineages, including an increased proliferative response of ovarian cancer cells both in vitro and in vivo, at least in part through the novel expression of LPA receptors. Thus, LPA hydrolysis is necessary to limit the duration of LPA's action on multiple cell types, including ovarian cancer cells. We determined the principal mechanism of LPA hydrolysis by ovarian cancer cells and its regulation by GnRH, which is known to have antiproliferative actions on ovarian carcinomas. LPA-hydrolyzing activity in cell membranes of ovarian cancer specimens was assessed by measuring the conversion of exogenous [3H-oleoyl]LPA to [3H]oleic acid or mono[3H-oleoyl]glycerol. Approximately 98% of LPA hydrolysis could be accounted for by the dephosphorylation of LPA to yield monoglyceride, with the deacylation reaction accounting for less than 1% of LPA hydrolysis. The phosphatase activity in the plasma membrane ovarian cancer cells was approximately 2.5- and 8-fold higher than those in microsome and homogenate fractions, respectively. The membrane phosphatase was Mg2+ independent and insensitive to inhibition by N-ethylmaleimide, characteristics suggestive of phosphatidic acid phosphatase activity. Incubation of membranes from GnRH receptor-positive ovarian cancer specimens with the GnRH agonist, buserelin, induced a dose-dependent increase in LPA phosphatase activity, with a half-maximal effect occurring with 30 nmol/L buserelin. The stimulatory action of buserelin could be neutralized by displacement of GnRH from its receptor by the GnRH antagonist, antide. The plasma membranes from GnRH receptor-negative ovarian cancer specimens did not respond to GnRH stimulation. LPA phosphatase activity was also increased when the ovarian cancer cell line Caov-3 was exposed to GnRH agonist in intact cells before assay of cell membranes. These data demonstrate that LPA is hydrolyzed in the plasma membrane of ovarian cancer cells by the action of LPA phosphatase and provide initial evidence for functional coupling of LPA phosphatase to GnRH receptor occupancy.

Adenocarcinoma, Clear Cell↗
PubMed2000

Difference by instructional set in stabilometry.

There is no standard for the awareness of standing posture in stabilometry, yet little research addressing the matter has been carried out. In the present study, we evaluated the influence of different instructional sets during a test on stabilometry. Stabilometry was performed on 349 male subjects. Two different instructions were prepared for the subjects regarding the awareness of their standing posture. These instructions were a) "Please relax when you stand" (R-standing), and b) "Please make an effort to minimize your body sway" (E-standing). Subjects were classified into four groups according to the combination of these instructions they received. For the five body sway parameters, a comparison between R-standing and E-standing was performed, controlling for possible confounders such as age, height, body weight, educational history, alcohol consumption, and smoking status. The sway length in E-standing was larger than that in R-standing, even after the adjustment for possible confounders. Our results indicate that the difference in the instructional set caused a significant measurement bias. Thorough-going unification of instructions for the stabilometry should be recommended when stabilometry is performed in an epidemiological investigation.

Adult↗
PubMed2000

Serum leptin correlates with serum uric acid but not serum testosterone in non-obese male adolescents.

To identify the serum factors that affect circulating leptin levels, we measured the serum concentrations of leptin, testosterone (T), estradiol (E), serum alanine aminotransferase, total cholesterol and uric acid (UA) in healthy male adolescents (age, 18.3 +/- 0.1 years, n=96). We also measured body mass index (BMI), percent body fat and thickness of skin fold to assess the effect of body constitution on serum leptin level. Since serum concentration of leptin significantly correlated with BMI (r=0.820, p<0.001), we analyzed the relation-ship between leptin/BMI ratio (L/BMI) and serum parameters. Analysis of data of subjects with normal serum T level showed a significant inverse correlation between L/BMI and serum T levels (n=96, r=-0.294, p<0.005), but no such correlation was present among non-obese subjects (n=70) with BMI of +/-20% of normal (22 kg/m2). There was no correlation between L/BMI and serum E level. Serum UA level significantly correlated with L/BMI in both the test group (n=96, r=0.520, p<0.001) and non-obese subjects (r=0.369, p<0.005). Stepwise multiple regression analysis showed that UA independently and significantly influenced serum leptin levels in both the test and control groups. Our results demonstrate that T weakly influences serum leptin concentration, and that UA concentrations strongly influences serum leptin in healthy male adolescents independent of their obesity level.

Adolescent↗
PubMed1999

Radiotherapy of early tongue cancer in patients less than 40 years old.

PURPOSE: To evaluate the results of treatment for early mobile tongue cancer in patients less than 40 years. METHODS AND MATERIALS: Between January 1967 and September 1992, 70 patients less than 40 years old (young age group) with early tongue cancer (T1-2N0M0) were treated with low-dose-rate (LDR) interstitial radiotherapy at the Osaka University Hospital (OUH). All patients had a minimum 2-year follow-up (median: 13 years). External radiotherapy (median: 30 Gy) was combined in 25 cases. The treatment results were compared with those for two older age groups (middle age: 40-64 years old; old age: 65 years old or more). RESULTS: The 5-year probability of cause-specific survival (CSS) rate for the young age group was 80%, which was not significantly different from the two older groups: 81% for middle age and 71% for old age. However, male patients of young age showed significantly worse rates than those of middle and old age (p = 0.02). The 5-year local control rate for the young age group was 78%. It was not significantly different from the two older groups: 81% for middle age and 70% for old age. The incidence of regional lymph node metastasis was 32% for T1, 48% for T2, 56% for males, and 24% for females. The regional failure rate of young males was significantly higher than those of the two older groups: 32% for middle and 22% for old age (p = 0.001). CONCLUSION: The overall treatment results for patients with early tongue cancer less than 40 years old were not worse than those of older age groups. However, male gender was a risk factor for lymph node metastasis and CSS.

Adult↗
PubMed1999

Perioperative fractionated high-dose rate brachytherapy for malignant bone and soft tissue tumors.

PURPOSE: To investigate the viability of perioperative fractionated HDR brachytherapy for malignant bone and soft tissue tumors, analyzing the influence of surgical margin. METHODS AND MATERIALS: From July 1992 through May 1996, 16 lesions of 14 patients with malignant bone and soft tissue tumors (3 liposarcomas, 3 MFHs, 2 malignant schwannomas, 2 chordomas, 1 osteosarcoma, 1 leiomyosarcoma, 1 epithelioid sarcoma, and 1 synovial sarcoma) were treated at the Osaka University Hospital. The patients' ages ranged from 14 to 72 years (median: 39 years). Treatment sites were the pelvis in 6 lesions, the upper limbs in 5, the neck in 4, and a lower limb in 1. The resection margins were classified as intracapsular in 5 lesions, marginal in 5, and wide in 6. Postoperative fractionated HDR brachytherapy was started on the 4th-13th day after surgery (median: 6th day). The total dose was 40-50 Gy/7-10 fr/4-7 day (bid) at 5 or 10 mm from the source. Follow-up periods were between 19 and 46 months (median: 30 months). RESULTS: Local control rates were 75% at 1 year and 48% in 2 years, and ultimate local control was achieved in 8 (50%) of 16 lesions. Of the 8 uncontrolled lesions, 5 (63%) had intracapsular (macroscopically positive) resection margins, and all the 8 controlled lesions (100%) had marginal (microscopically positive) or wide (negative) margins. Of the total, 3 patients died of both tumor and metastasis, 3 of metastasis alone, 1 of tumor alone, and 7 showed no evidence of disease. Peripheral nerve palsy was seen in one case after this procedure, but no infection or delayed wound healing caused by tubing or irradiation has occurred. CONCLUSION: Perioperative fractionated HDR brachytherapy is safe, well tolerated, and applicable to marginal or wide surgical margin cases.

Adolescent↗
PubMed1999

A kuroko-type polymetallic sulfide deposit in a submarine silicic caldera

Manned submersible studies have delineated a large and actively growing Kuroko-type volcanogenic massive sulfide deposit 400 kilometers south of Tokyo in Myojin Knoll submarine caldera. The sulfide body is located on the caldera floor at a depth of 1210 to 1360 meters, has an area of 400 by 400 by 30 meters, and is notably rich in gold and silver. The discovery of a large Kuroko-type polymetallic sulfide deposit in this arc-front caldera raises the possibility that the numerous unexplored submarine silicic calderas elsewhere might have similar deposits.

Journal Article↗
PubMed1999

A novel sex-determining region on Y (SRY) nonsense mutation identified in a 45,X/47,XYY female.

OBJECTIVE: To determine whether an SRY mutation participated in the phenotypic outcome in the case of a 45,X/47,XYY female. DESIGN: Analysis of genomic DNA for mutations in SRY. SETTING: An academic teaching hospital. PATIENT(S): A family that included one phenotypic female with 45,X/47,XYY mosaicism. INTERVENTION(S): Extraction of DNA, polymerase chain reaction analysis, nucleotide sequencing, and restriction enzyme analysis. MAIN OUTCOME MEASURE(S): Comparison of control and subject DNA sequences. RESULT(S): The patient demonstrated one nucleotide (thymine, T) deletion at position 422, leading to a frame-shift mutation. This mutation changes the codon for Tyr (TAT) to a stop codon (TAG) within the open reading frame just upstream of a conserved DNA-binding motif. Neither other mutations nor nucleotide mosaicisms were found in the remaining regions of the gene. This mutation was not present in the patient's normal father. CONCLUSION(S): The mutant SRY may be assumed to induce a nonfunctional SRY-coded protein that lacks a DNA-binding motif. These results explain the phenotypic female and the gonadal dysgenesis in the 45,X/ 47,XYY sex-reversed offspring.

Amino Acid Sequence↗
PubMed1999

IgE reactivity to alpha1 and alpha2 chains of bovine type 1 collagen in children with bovine gelatin allergy.

BACKGROUND: Anaphylactic reactions to measles, mumps, and rubella vaccines, including gelatin as a stabilizer, have been reported. It had been found that most of these reactions to live vaccines are caused by the bovine gelatin included in these vaccines. Gelatin mainly includes denatured type I collagen, which consists of alpha1 and alpha2 chains. OBJECTIVE: The current study was designed to investigate the IgE reactivity to alpha1 and alpha2 chains of bovine type I collagen in gelatin-sensitive children. METHODS: Serum samples were taken from 10 children who had anaphylaxis to the vaccines and high levels of specific IgE to bovine gelatin. Bovine type I collagen was isolated from bovine skin and then separated to alpha1 and alpha2 chains by column chromatography. IgE reactivity to denatured type I collagen and its alpha1 and alpha2 chains was analyzed by immunoblotting, ELISA, and histamine release from the mast cells passive sensitized with IgE antibodies in pooled serum of the children. RESULTS: All children had specific IgE to bovine type I collagen. Furthermore, IgE antibodies in their sera reacted with the alpha;2 chain but not with the alpha1 chain. Similarly, the mast cells sensitized with pooled sera in the children showed alpha2 chain-specific histamine release but not alpha1 chain-specific histamine release. CONCLUSION: In gelatin allergy denatured bovine type I collagen is a major allergen and IgE-binding sites exist in the alpha2 chain of type I collagen.

Anaphylaxis↗
PubMed1999

Brain metastasis as first manifestation of ovarian cancer.

Brain metastasis from ovarian cancer, a rare and highly dismal event, develops mostly during or after postoperative chemotherapy. This report documents the clinical findings and magnetic resonance imaging of an uncommon case who presented signs of increased intracranial pressure as a first manifestation. Histologic examination of removed brain lesion demonstrated ovarian origin, while no evidence of a locally invasive lesion was found at exploratory laparotomy ('tentative' surgical stage Ia). The possibility of ovarian origin should be always considered in a woman with brain involvement.

Adult↗
PubMed1999

Comparison of phosphodiesterase isozymes in rodent parotid glands.

We investigated phosphodiesterase (PDE) isozymes, which hydrolyze cAMP, in rodent parotid glands (mouse, hamster and guinea pig) in order to clarify the effects of cGMP and Ca/calmodulin on the regulation of cellular cAMP and compared them with those of the rat. More than 80% of the activities were in the supernatant fractions except for the hamster. The isozymes were fractionated using Mono Q ion-exchange column. The mouse parotid PDEs consisted of PDE1 (Ca/calmodulin-dependent), PDE2 (cGMP-stimulated), PDE3 (cGMP-inhibited) and PDE4 (cAMP-specific) similar to those of the rat. PDE3 was not detected in the hamster, and PDE4 was not detected in the guinea pig. PDE activities in the supernatant of the mouse and the hamster were stimulated by cGMP, and that of the guinea pig was stimulated by Ca/calmodulin. These results suggest that various PDE isozymes are present in the parotid gland of several species of order Rodentia. There seems to be differences among the species with regard to the PDE isozymes.

Animals↗
PubMed1999

Relationship between serum leptin and fatty liver in Japanese male adolescent university students.

OBJECTIVE: The aim of this study was to elucidate the relationship between serum leptin levels and fatty liver in male adolescents. METHODS: We investigated the relationship between the concentration of circulating leptin and fatty liver by measuring the serum concentration of leptin in 284 male students who received the matriculation health examination in Okayama University in 1996 (n = 197; age, 18-20 yr) or 1997 (n = 87; age, 18-20 yr). RESULTS: Serum leptin levels correlated positively with body mass index (BMI), percent body fat (%FAT), thickness of skin fold (TSF), and serum concentration of ALT in 197 subjects. Examination of serum leptin in 67 subjects with BMI > or = 24.2 but < 28.6 kg/m2 showed a progressively higher levels in subjects with high serum ALT. Serum leptin levels in subjects with abnormally high serum ALT (> or = 37 IU/L) were significantly higher (p < 0.05) than in subjects with normal serum ALT, independent of BMI, %FAT, and TSF. Serum leptin levels were also significantly higher in subjects with fatty liver (detected by abdominal ultrasonography), independent of BMI and %FAT, compared with subjects without fatty liver. Stepwise multiple regression analysis showed that serum leptin level was an independent risk factor for fatty liver. In addition, serum leptin levels correlated with serum ALT (r = 0.518; p < 0.0005) and cholinesterase (r = 0.511; p < 0.0005) levels in 48 subjects with fatty liver. CONCLUSIONS: Our results demonstrated that serum leptin concentrations are high in male adolescents with simple obesity and are associated with high serum ALT or fatty liver, independent of BMI and %FAT, suggesting that the concentration of circulating leptin correlates with fatty liver caused by accumulation of visceral fat.

Adipose Tissue↗
PubMed1999

A mild transient decrease of peripheral red blood cell counts induced by a suprapharmacological dose of pegylated human megakaryocyte growth and development factor in rats.

Previous studies have shown that pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) at suprapharmacological dose induces a mild transient decrease of red blood cell counts according to thrombopoiesis in normal mice. To unravel the mechanism underlying this mild transient decrease of red blood cells, we have studied the effect of PEG-rHuMGDF on the circulating plasma and blood volume, and the serum biochemical parameters of anaemia and splenectomy. Also, we have performed histological studies of the bone marrow and the spleen of PEG-rHuMGDF-treated rats. PEG-rHuMGDF (300 microg kg(-1)]) or vehicle was subcutaneously administered to rats once a day for up to five days. From day 6 after the start of PEG-rHuMGDF administration, the platelet counts and plateletcrit levels were significantly increased, reaching peak values on day 10, and recovering to normal by day 20. The red blood cell counts and the haematocrit levels were significantly decreased on day 6 to 13. The decreases in red blood cell levels and haematocrit produced by PEG-rHuMGDF treatment were mild and had recovered by day 15. The plasma and blood volumes were significantly increased on day 10 in PEG-rHuMGDF-treated rats. No alteration of the serum biochemical parameters for anaemia, iron or total bilirubin, were observed on day 10. The histological examination on day 10 revealed a marked increase in megakaryocytes and a slight decrease in erythropoiesis in the bone marrow of rats that received PEG-rHuMGDF (300 microg kg(-1)). There was also a slight increase in splenic megakaryocytes and erythropoiesis. The decrease of red blood cells by PEG-rHuMGDF was not affected by splenectomy. These results suggest that the mild transient decrease of red blood cells induced by PEG-rHuMGDF treatment for up to five days is based mainly on the increases in the plasma and blood volume. These events are secondary changes due to the regulation of the excess production of megakaryocytes in the marrow and the peripheral platelets.

Anemia↗
PubMed1999

A novel sex-determining region on Y (SRY) missense mutation identified in a 46,XY female and also in the father.

Mutations in the sex-determining gene SR Y previously identified occur in the 46, XY females. In this study, we investigated whether the SR Y mutation participates in the onset of XY sex reversal. Genomic deoxyribonucleic acids (DNA) from five XY sex-reversed females were analyzed for mutations in SR Y using polymerase-chain reaction (PCR) amplification and subsequent DNA sequencing. One of the 46, XY females suffered a novel missense mutation at position 306 of SR Y gene, wherein cytosine was replaced by adenine (CGC-->AGC), resulting in a substitution of serine for arginine at amino acid position 76 of SR Y protein. This mutation was located in Helix I of the high-mobility-group (HMG) domain. No other mutations were found in the remaining regions of the gene. Analysis of the SR Y gene in her father revealed that he carried the identical mutation version. This substitution introduces a large basic for a small polar uncharged amino acid residue in the HMG box. The fact that the father transmits the mutant SR Y copy to his offspring implies that SR Y mutations do not always occur in association with sex reversal, even when the ionic environment is altered.

Adult↗
PubMed1999

Pancreatic phospholipase A2 induces bacterial translocation in rats.

The importance of pancreatic enzymes, particularly phospholipase A2 (PLA2), for bacterial translocation, which is considered to be one of the aggravating causes of acute pancreatitis, was investigated. Male rats were administered an intraperitoneal or intravenous injection of normal saline, PLA2, or amylase. Four days later, the mesenteric lymph nodes (MLNs) and portal blood of the animals were cultured. None of the animals had a positive portal blood culture. The MLNs contained enteric bacteria in 78% of the animals given 50 mg/kg of PLA2 intraperitoneally. 5 mg/kg of PLA2 intraperitoneally, 50 mg/kg of amylase intraperitoneally, or 50 mg/kg of PLA2 intravenously showed positive cultures in 25%, 20%, and 11%, respectively. None of the animals given intraperitoneal or intravenous normal saline had positive cultures of their MLNs. Intraperitoneal injection of 25 mg/kg of nafamostat mesilate just before intraperitoneal PLA2 (50 mg/kg) resulted in a reduction of positive MLNs from 70% to 30%. The cecal myeroperoxidase (MPO) activity of animals administered 50 mg/kg of PLA2 intraperitoneally was significantly higher compared with animals administered saline intraperitoneally. These results indicate that intraperitoneal leakage of PLA2 plays an important role in bacterial translocation during acute pancreatitis and that administration of a protease inhibitor may be effective against the bacterial translocation.

Acute Disease↗
PubMed1999

PEG-rHuMGDF ameliorates thrombocytopenia in carboplatin-treated rats without inducing myelofibrosis.

We examined the effects of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) on carboplatin-induced thrombocytopenia in rats. The focus was on whether myelofibrosis is associated with the PEG-rHuMGDF treatment in this chemotherapy model. After a single injection of carboplatin, rats received subcutaneous PEG-rHuMGDF at pharmacologic doses (1,3, or 30 micrograms/kg) or a vehicle daily for 7 days. PEG-rHuMGDF at more than 3 micrograms/kg ameliorated the thrombocytopenia at day 10. Histologically, no myelofibrosis was detected in the rats treated with PEG-rHuMGDF or vehicle. Subsequently, PEG-rHuMGDF at a suprapharmacologic dose (100 micrograms/kg) was subcutaneously administered to normal and to carboplatin-treated rats daily for 7 days. Histological analysis revealed that the treatment with PEG-rHuMGDF induced myelofibrosis in the normal rats but not in the carboplatin-treated rats. Additionally, the transforming growth factor-beta 1 (TGF-beta 1) levels in the extracellular fluid and the whole extract of the bone marrow were increased to a much lesser degree in the carboplatin-treated rats compared to the normal rats. These findings suggest that PEG-rHuMGDF is effective for carboplatin-induced thrombocytopenia. Proper control of platelet counts and TGF-beta 1 levels is essential so that myelofibrosis is not induced in clinical use.

Animals↗
PubMed1999

[A case of AIDS-associated primary CNS lymphoma difficult to differentiate from toxoplasmic encephalitis by clinical symptoms, neuroimages, and therapeutic responses].

We reported a 24-year-old Thai woman who developed primary CNS lymphoma (PCNSL) associated with acquired immunodeficency syndrome. It was difficult to distinguish PCNSL from toxoplamic encephalitis in this case by clinical symptoms, findings of CT and MRI, and therapeutic responses for toxoplasmosis. It is important to make a definite diagnosis of PCNSL by brain biopsy to treat appropriately, because this disorder could be fatal if it is not treated by corticosteroid, radiation, or other proper methods.

Adult↗