Search PubMed⌕ Search

Biomedical subjects

S Nakata

Publications and source records attributed to S Nakata.

At least 91 records · Page 5Linked to original sources

[A case of pure leiomyoma of the prostate].

Pure leiomyoma of the prostate is very rare. A 67-year-old man was hospitalized with gross hematuria and urinary retention. Drip infusion pyelography revealed a defect of the urinary bladder. By radiological examinations, submucosal tumor of the bladder neck was diagnosed. Transrectal biopsy suggested a benign prostatic tumor histologically. Open resection of the tumor was performed. Histological findings were pure leiomyoma of the prostate. The postoperative course was good and urinary retention was improved remarkably.

Aged↗

[A case positive for the inhibitor for coagulation factor V].

We report a 71-year-old man who exhibited hepatocellular carcinoma and the inhibitor for coagulation factor V (FV). The inhibitor was found when his coagulation screening tests revealed an abnormally prolonged prothrombin time (71.1 sec) and activated partial thromboplastin time (more than 120 sec) but normal values of fibrinogen (241 mg/dl), the thrombo test (84%) and hepaplastin test (71%). In addition, FV-coagulation activity of the patient's plasma showed less than 1% of the pooled normal plasma and inhibitory activity for FV of his plasma was 32 Bethesda units. This inhibitory activity was neutralized by the addition of anti-human immunoglobulin-gamma-chain serum. The patient was treated with a fibrin sealant including human thrombin when he underwent an partial hepatectomy (32 months before onset) and received 2 doses of thrombin orally (5 months and 2 weeks before onset) to stop bleeding from phlebeurysm. Several studies have reported that the inhibitor for FV was produced after treatment with bovine thrombin containing FV as a contaminant. These findings suggest that our patient may produce an immunoglobulin specific for FV after similar stimulation of human thrombin containing FV.

Aged↗

Relationship of membrane curvature to the formation of pores by magainin 2.

Magainin 2, an antimicrobial peptide from the Xenopus skin, kills bacteria by permeabilizing the cell membranes. We have proposed that the peptide preferentially interacts with acidic phospholipids to form a peptide-lipid supramolecular complex pore, which allows mutually coupled transbilayer traffic of ions, lipids, and peptides, thus simultaneously dissipating transmembrane potential and lipid asymmetry [Matsuzaki, K., Murase, O., Fujii, N., and Miyajima, K. (1996) Biochemistry 35, 11361-11368]. In this paper, we examined the effect of membrane curvature strain on pore formation. Magainin effectively forms the pore only in phosphatidylglycerol bilayers at low peptide-to-lipid ratios, well below 1/100. In contrast, the permeabilization of phosphatidylserine, phosphatidic acid, or cardiolipin bilayers occurred at much higher peptide-to-lipid ratios (1/50 to 1/10) with some morphological change of the vesicles. The latter three classes of phospholipids are known to form hexagonal II structures under conditions of reduced interlipid electrostatic repulsions. Incorporation of phosphatidylethanolamine also inhibited the magainin-induced pore formation in the inhibitory order of dioleoylphosphatidylethanolamine > dielaidoylphosphatidylethanolamine. Addition of a small amount of palmitoyllysophosphatidylcholine enhanced the peptide-induced permeabilization of phosphatidylglycerol bilayers. Magainin greatly raised the bilayer to hexagonal II phase transition temperature of dipalmitoleoylphosphatidylethanolamine. These results suggest that the peptide imposes positive curvature strain, facilitating the formation of a torus-type pore, and that the presence of negative curvature-inducing lipids inhibits pore formation.

Amino Acid Sequence↗

Involvement of vascular endothelial growth factor and urokinase-type plasminogen activator receptor in microvessel invasion in human colorectal cancers.

To evaluate the association among known angiogenic growth factors or factors related to the plasminogen activation system and clinicopathological factors in patients with colorectal cancer, we examined the expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), transforming growth factor-alpha (TGF-alpha), urokinase-type plasminogen activator (u-PA), u-PA receptor (u-PA-R) and plasminogen activator inhibitor-1 (PAI-1) in clinical specimens of colorectal cancers by Northern blot analysis. In comparison with the expression of these angiogenesis-related genes in 7 paired samples of colorectal cancers and the adjacent normal mucosa, VEGF mRNA level was significantly higher in the cancer tissues than in the adjacent normal mucosa (p < 0.05). We analyzed expression of these genes in 44 cases of primary colorectal cancers. Among the 3 angiogenic growth factors we examined, VEGF mRNA expression was significantly higher in the cancer tissues with blood vessel invasion or with lymphatic vessel invasion than in those without, respectively (p < 0.05). On the other hand, u-PA-R mRNA expression was significantly higher in the cancers with blood vessel invasion than in those without (p < 0.05). In addition, there was a correlation between the expression levels of VEGF and u-PA-R mRNA in the cancer tissues we have examined. Using immunohistochemistry, strong staining of VEGF or u-PA-R was observed in the cancer cells invading the microvessels. Our findings suggest that malignant transformation might accompany the upregulation of VEGF expression in colorectal cancers and that VEGF and u-PA-R might contribute cooperatively to increase angiogenesis around the tumor as well as the metastasis via microvessels.

Adult↗

A novel vascular modulator, hepatocyte growth factor (HGF), as a potential index of the severity of hypertension.

HGF (hepatocyte growth factor), a member of endothelium-specific growth factors, might contribute to protection and/or repair of vascular endothelial cells injured by high blood pressure (BP). If so, serum HGF level might be elevated in response to endothelial cell damage. To test this hypothesis, we measured serum levels of HGF in hypertensive and normotensive patients. Serum HGF concentration in hypertensive patients without any complication was significantly higher than normal subjects (p < 0.001). Serum HGF concentration showed a significant positive correlation with BP (p < 0.01). Interestingly, serum HGF concentration in hypertensive patients with complications was significantly higher than that in hypertensive patients without complication and normotensive subjects (p < 0.01). Of importance, hypertensive patients treated with antihypertensive drugs showed the same level of serum HGF concentration as normotensive subjects (p < 0.001). The present study demonstrated that serum concentration of HGF is significantly elevated dependent on the severity of hypertension, suggesting that HGF may be a new index of the severity of hypertension.

Antihypertensive Agents↗

Multiple carcinoids of the duodenum accompanied by type I familial multiple endocrine neoplasia.

A case of multiple carcinoid tumors of the duodenum accompanied by familial multiple endocrine neoplasia is reported. A 46-year-old man with duodenal polyps discovered during a mass screening was followed up for 5 years. In August 1994, a histological examination revealed carcinoid tumors, and he was thus referred to our hospital for surgery. He underwent a parathyroidectomy and cholecystectomy for primary hyperparathyroidism and cholecystolithiasis, respectively. The patient's sister had also undergone a parathyroidectomy and distal pancreatectomy for primary hyperparathyroidism and insulinoma of the pancreas. In addition, his two children were also followed up for hypercalcemia. A serum examination of the patient revealed high levels of somatostatin and pancreatic polypeptide, but normal levels of gastrin and serotonin. In November 1994, a pancreaticoduodenectomy with a D2 lymph node dissection was performed. The macroscopic findings of the resected specimen showed multiple polypoid lesions with delles on the top, measuring 3 to 15 mm in size throughout the duodenum. A microscopic examination revealed the tumor to have infiltrated into the submucosa extensively, and an immunohistochemical analysis also demonstrated the tumor cells to be positive for somatostatin, but not for pancreatic polypeptide. After surgery, the serum level of somatostatin returned to normal but the pancreatic polypeptide remained high. The post-operative course was uneventful, and the patient remains in good health.

Carcinoid Tumor↗

Effects of effusion in the middle ear and perforation of the tympanic membrane on otoacoustic emissions in guinea pigs.

The influence of fluid in the middle ear and of perforation and closure of the tympanic membrane (TM) on otoacoustic emissions (OAEs) was evaluated in guinea pigs. Click-evoked otoacoustic emissions (CEOAEs) and distortion product otoacoustic emissions (DPOAEs) were measured after the auditory bulla was opened. Neither OAE level changed significantly when fluid filled only half the space in the bulla, but both OAE levels disappeared when fluid completely filled the bulla. These changes were reversible. Thus, the presence of fluid in the bulla influenced CEOAE and DPOAE levels only when its volume filled more than half the space of the bulla. Changes in both CEOAE and DPOAE levels were affected by the size of the perforation of the tympanic membrane. For the smallest perforation, the reduction in both CEOAE and DPOAE levels was restricted to the lower frequencies. However, as the size of the perforation increased, a decrease in high-frequency function occurred. Thus, the results indicate that the magnitude of both OAEs was proportional to the size of the perforation. Both OAE levels improved after the perforation was closed. Because CEOAEs were more sensitive than DPOAEs to perforation and closure of the TM, DPOAEs may be better suited for OAE measurement in ears with perforated TMs.

Acoustic Stimulation↗

CMDME (curved mesh diagram of mandibular excursion) method for visualization and diagnosis of mandibular movement.

The CMDME (curved mesh diagram of mandibular excursion) method was developed for easy visualization and diagnosis of mandibular movement. This method uses measured mandibular movement to produce a diagram of the range, shape, and inclination of mandibular excursion in three dimensions using any arbitrary landmark of the mandible. First, the mandibular movement of a subject was measured by an opto-electronic movement analysis system capable of measuring mandibular movement with six degrees-of-freedom at a sampling frequency of 100 Hz. For the measurement, the subject was initially instructed to perform four repetitions of mandibular excursion at will, with tooth contact, each lasting 30 s. A total of 12 000 positions of the mandible were thus obtained. Secondly, an attempt was made to match these positions to intersection points (0.1 mm apart) of a CMDME (i.e. mesh) for arbitrary mandibular landmarks with intercuspal position at the origin. The CMDME method can visualize mandibular excursion, and can be used to compare several landmarks, different subjects, or different times. This makes this method an effective diagnostic tool for mandibular movement.

Adult↗

A boy with fatal infectious mononucleosis suspected as the first Japanese case of X-linked lymphoproliferative syndrome.

We report a case of a 10-month-old boy who died of severe hepatic failure after a prolonged course of infectious mononucleosis. He also presented interstitial pneumonitis, meningoencephalitis and aplastic anaemia. Epstein-Barr virus (EBV)-specific cytotoxic T lymphocyte (CTL) activity had not been detected in his peripheral blood during the course of the illness. Studies of his mother revealed a severe reactivation pattern of anti-EBV antibodies and decreased EBV-specific CTL activity. An X-linked familial susceptibility to EBV infection such as X-linked lymphoproliferative syndrome (XLP) might be associated with his fatal EBV infection.

Cytotoxicity, Immunologic↗

Increased proliferation of myoblasts after cyclic plasma perfusion of tumor-bearing rabbits.

Rabbits implanted with VX2 carcinoma and treated by cyclic plasma perfusion showed lower weight loss and longer survival than untreated rabbits. The urinary 3-methylhistidine/creatine ratio was less elevated in the treated rabbits than in the untreated rabbits. Myoblasts from untreated rabbits with VX2 carcinoma showed lower proliferation than those from normal rabbits, while those from rabbits treated by cyclic plasma perfusion showed intermediate proliferation. Furthermore, the DNA synthesis rate of myoblasts from treated rabbits was much better maintained than in the case of untreated rabbits.

Animals↗

Familial prostate cancer in Japan.

BACKGROUND: Familial prostate cancer has been studied in Europe and the United States. This study was conducted to clarify the clinical features and incidence of the human leukocyte antigen (HLA) in familial prostate cancer in patients seen at hospitals in Japan. METHODS: The age at diagnosis, clinical stage, histologic differentiation, prognosis, cause of death and family history were compiled from 43 patients from 20 families with familial prostate cancer (group F) and compared in patients with sporadic prostate cancer (group S). In addition, HLA class II gene typing was performed in 17 patients from 11 families with familial prostate cancer (group F') and their healthy family members (15 males and 25 females). RESULTS: The age at diagnosis was significantly lower in group F patients (P< 0.001), but neither clinical stage nor prognosis differed between group F and group S, yet the incidence of moderately differentiated adenocarcinoma was significantly higher in group F (P< 0.01 ). There were no historical factors that were specific for group F patients. The frequency of HLA-DRB1 *0901 and *1201 alleles was significantly higher in group F' patients than in group J (the frequency of alleles in 1216 Japanese people attending the 11th Japan HLA Workshop), but not between group F' and their healthy male family members. CONCLUSION: There were no significant differences in clinical parameters between group F and group S, except that the age at diagnosis was lower in group F patients, and that the frequency of several HLA class 11 alleles was significantly higher in patients with prostate cancer. In men with a family history of prostate cancer, examinations for early detection of prostate cancer should begin at a young age.

Aged↗

Incidence of urogenital cancers in Gunma Prefecture, Japan: a 10-year summary.

BACKGROUND: Although the incidence of urogenital cancers in Japan is lower than that of other cancers, it is increasing steadily. Thus, an epidemiologic study was necessary to determine the measures that would decrease the mortality rate associated with these cancers. METHODS: The subjects were 4759 patients with urogenital cancer who were living in Gunma Prefecture and who were newly diagnosed between 1985 and 1994. The data were analyzed by year and by patients' ages. The incidence rates of each disease were expressed as the number of cases per 100,000/year, and age-adjusted rates were adjusted to the world population. RESULTS: The number of males and females afflicted by urogenital cancers increased over the 10-year period. The increase in age-adjusted incidence rates was sharpest for prostate, renal cell, and testicular cancers among males, and for renal cell, renal pelvic and ureter cancers among females. When age-specific rates were plotted against age on double logarithmic scales, the cancers were classified as type 1 (linear), type 2 (linear until a certain age, then flattening out or decreasing), or type 3 (irregular) based on the slope of the line. The magnitude of increase in the age-specific incidence rates of type 1 cancers with age was on the order of the 12th power for prostate cancer and the 5th power for bladder cancer. When the 10 years were divided into 2 periods (earlier and later), the age-specific incidence rates of prostate and renal cell cancers increased in all age groups, whereas the age-specific incidence rates of cancers that increased less sharply remained stable or even declined in some age groups. CONCLUSION: These epidemiologic data should be useful in reducing the mortality rates associated with these cancers.

Adult↗

Familial prostate cancer in four brothers.

We identified a family of 4 brothers with prostate cancer. The proband was the second son who was seen at the Department of Urology, Gunma University, Gunma, Japan, in May 1995, with a chief complaint of dysuria. The serum level of PSA was high, and a prostate needle biopsy revealed a moderately-differentiated adenocarcinoma. Subsequently, a total prostatectomy was performed. The family history revealed that the fourth son had been under treatment at the Saitama Cancer Center Hospital for prostate cancer since 1994. Therefore, the other 2 brothers became healthy male family members of the familial prostate cancer line, and their serum PSA levels were examined after obtaining their informed consent. Both had a high serum PSA level and biopsies revealed moderately-differentiated adenocarcinomas in both. Human leukocyte antigen class II gene typing was conducted on 3 of 4 brothers and 4 healthy family members who gave informed consent, and revealed the DRB1*0901-DQB1*0303 haplotype in the first, second and third sons. Familial prostate cancer is well documented in Europe and the US where the incidence of prostate cancer is high, but this is the first report of prostate cancer in 4 brothers in Japan.

Adenocarcinoma↗

Prevalence of human calicivirus infections in Kenya as determined by enzyme immunoassays for three genogroups of the virus.

An epidemiological survey on human calicivirus (HuCV) infections and associated gastroenteritis in infants was conducted to clarify the prevalence of HuCV infections in infants and adults in Kenya. Enzyme immunoassays (EIAs) for three genogroups of HuCVs, Norwalk virus (NV), Mexico virus (MXV), and Sapporo virus (SV), were used to detect antigen or antibody. We tested 1,431 stool samples obtained from children younger than 6 years old with acute gastroenteritis who visited outpatient clinics in three districts in Kenya from August 1991 to July 1994. Thirty-two (2.2%) of these stool samples were positive for SV antigen. Only one (0.1%) of 1,186 samples was positive for NV antigen and none of 246 samples was positive for MXV antigen. One hundred ninety-three serum samples were tested for antibodies to NV and MXV, and 64 of them were examined for antibody to SV. The pattern of the age-related prevalence of serum antibody to NV was different from that of antibodies to MXV and SV. The acquisition of serum antibodies to HuCVs in the three genogroups appeared in early childhood, at about 1 to 2 years of age. The prevalence of serum antibody to NV was low (about 60%) throughout adulthood compared with a high prevalence of antibody (approximately 80 to 90%) to MXV and SV. These data indicate that infections with viruses in the three genogroups of HuCVs are common in Kenya, and immunological responses to NV may be different from those to MXV and SV. The EIAs for the detection of NV and MXV antigens appear to be quite specific for prototype NV and MXV strains, respectively, so that they can detect only a few strains of HuCVs related to them. Alternatively, NV and MXV caused less severe infections that did not bring children to the outpatient clinics for gastroenteritis in Kenya.

Adolescent↗