Biomedical subjects

Yoshitaka Tamura

Publications and source records attributed to Yoshitaka Tamura.

At least 19 recordsLinked to original sources

PubMed2007

Prediction of aortic peak enhancement in monophasic contrast injection protocols at multidetector CT: phantom and patient studies.

PURPOSE: The aim of this study was to investigate whether it is possible to predict aortic peak enhancement (APE) from the contrast dose and injection rate. MATERIALS AND METHODS: We first undertook an experimental study using a flow phantom that simulates the human circulation. We delivered 90-150 ml of iomeprol-350 at various injection rates and measured the APE values of the simulated aorta. In our clinical study we randomized 20 patients into four groups. In groups A, B, and C the iodine dose per kilogram of body weight (BW) ranged from 450 to 600 mg, and the injection duration was fixed at 30 s; group D received 450 mg/kg over 25 s. We then measured APE in all patients at the whole aorta, averaged the three highest values, and took the result as APE. RESULTS: In the phantom study, the decision coefficient for the best-fit equation obtained by multiple regression analysis of the relation between the iodine dose and injection rate and the simulated APE was high (0.93). In the patient study, the predicted APE values almost corresponded with the averaged APE values when we applied the fitness equation. CONCLUSION: Using our fitness equation, APE on contrast-enhanced computed tomography can be predicted from the iodine dose and the contrast injection rate per patient weight.

Adult↗

PubMed2006

Hemorrhage into pancreatic pseudocyst.

We report a patient whose upper abdominal pain was due to an alcoholic pancreatic pseudocyst with hemorrhage. CT showed a gradually enhancing pancreatic pseudocyst about 6 cm in diameter. It exhibited hyposignal intensity on T2-weighted images and hypersignal intensity on T1-weighted images. Enlargement of the pancreatic pseudocyst was thought to be attributable to hemorrhage into the pancreatic pseudocyst. Angiography revealed a pseudoaneurysm in the anterior superior pancreaticoduodenal (ASPD) artery. Selective transcatheter arterial embolization (TAE) of the ASPD artery stopped the bleeding and his abdominal pain lessened. After 1 month, the diameter of the pseudocyst was reduced to about 3 cm and it showed hypersignal intensity on T2-weighted images and hyposignal intensity on T1-weighted images. TAE was considered to be a minimally invasive, highly effective treatment in this patient with hemorrhage into a pancreatic pseudocyst.

Aneurysm, False↗

PubMed2006

Ectopic cervical thymus in an infant.

We report a case of accessory cervical thymus presenting as a unilateral neck mass in a 2-month-old boy. Ultrasonography (US) showed a mass isoechogenic to muscle in the left neck. Computed tomography (CT) revealed a well-defined, mildly enhanced mass located anterior to the sternocleidomastoid muscle, anterolateral to the carotid sheath, and posterior to the submandibular gland. On magnetic resonance imaging (MRI), the mass was isointense to muscle on T1-weighted images and hyperintense to muscle on T2-weighted images. Diffusion-weighted images showed relatively low apparent diffusion coefficient (ADC) values, and the mass was slightly enhanced after administration of contrast material. We suspected ectopic thymus, but we could not exclude the possibility of a malignant lesion. Therefore, the tumor was surgically resected. The histological diagnosis was ectopic cervical thymus. Ectopic thymus should be included in the differential diagnosis of a submandibular or cervical mass in infants. US and MRI can provide useful information for the diagnosis of ectopic cervical thymus.

Biomarkers, Tumor↗

PubMed2006

Oral administration of lactoferrin increases NK cell activity in mice via increased production of IL-18 and type I IFN in the small intestine.

Evidence that lactoferrin (LF) influences various immune functions is now accumulating. Recent reports have shown that bovine LF (BoLF) enhances antimicrobial, antiviral, and antitumor immune activities when orally administered. Here, we report that orally administered BoLF increases natural killer (NK) cell populations in peripheral blood and spleen in a dose-dependent manner and enhances interferon-gamma (IFN-gamma) production by NK cells. Using intraperitoneal (i.p.) injection of poly(I:C) to induce NK cell trafficking into the peritoneum, oral BoLF increased NK cell migration. Oral BoLF also produced an immediate increase in the levels of interleukin-18 (IL-18) in the portal circulation. In IL-18 knockout (KO) mice, BoLF did not increase the numbers of NK cells, although NK cell cytotoxic activity and poly(I:C)-induced trafficking activity were both enhanced by oral BoLF, even in IL-18 KO mice. Furthermore, oral BoLF increased the expression of IFN-alpha and IFN-beta in Peyer's patches (PP) and mesenteric lymph nodes (MLN). Oral administration of 2- chloroadenosine selectively depleted the PP cells and blocked the ability of oral BoLF to increase NK cell accumulation in the peritoneum following poly(I:C) i.p. injection. Collectively, these results demonstrate that orally administered BoLF stimulates intestine-associated immune functions, including the production of IL- 18 and type I IFNs and increased NK cell activity.

Administration, Oral↗

PubMed2006

Modulation of immunity-related gene expression in small intestines of mice by oral administration of lactoferrin.

Oral administration of lactoferrin (LF), an antimicrobial and immunomodulatory protein, shows a protective effect against infectious diseases, possibly via immunomodulation of the host. Initially, we confirmed an immunomodulatory effect of LF by observing changes in the number of cells in the leukocyte subsets in the peripheral blood and spleens of mice 1 day after oral administration of LF. Then we developed a quantitative reverse transcription-PCR method for 20 immunity-related genes of antimicrobial proteins, pattern recognition receptors, cytokines, and lymphocyte mobilization-related proteins, and we assessed the expression of these genes in the small intestines of mice 2 h after administration of water, bovine serum albumin (BSA), or LF. Expression of the LF gene was lower in mice administered LF than in mice administered water or BSA, implying a negative-feedback control. Expression of gamma interferon (IFN-gamma) and interleukin-10 (IL-10) was lower in both BSA- and LF-administered mice than in water administered mice, suggesting a nonspecific effect of protein ingestion. Expression of NOD2, IFN-beta, and IL-12p40 was higher with LF administration than with water or BSA administration. The expression levels of these three genes were correlated. This study indicated that oral administration of LF modulates the small intestinal expression of genes closely related to the host defense in a specific or a nonspecific manner.

Administration, Oral↗

PubMed2006

16-MDCT aortography with a low-dose contrast material protocol.

OBJECTIVE: The objective of our study was to evaluate whether a low-dose contrast material (CM) protocol with a saline flush might provide sufficient contrast enhancement in aortoiliac 16-MDCT angiography. SUBJECTS AND METHODS: Forty-five patients were divided into two groups on the basis of the CM (300 mg I/mL) administration protocol: group 1 (23 patients) received 100 mL of CM at 3.0 mL/sec; and group 2 (22 patients), 50 mL of CM at 3.0 mL/sec followed by a 20-mL saline flush at 3.0 mL/sec. All patients underwent 16-MDCT angiography of the entire aortoiliac region. Seven regions of interest (ROIs) were drawn from the ascending aorta (ROI 1) to the external iliac artery (ROI 7). Quantitative analysis was performed by calculating the mean aortoiliac attenuation and the mean difference between the maximum and minimum attenuation values. Vascular enhancement of the renal arteries was visually assessed using 2D and 3D postprocessing techniques. RESULTS: The mean aortoiliac attenuation in group 1 was 314.3 +/- 45.9 H and that in group 2 was 306.1 +/- 35.0 H. The difference was not statistically significant. Adequate mean aortoiliac attenuation was achieved in 95.7% (22/23) and 95.5% (21/22) of patients in groups 1 and 2, respectively. The difference was not statistically significant. The mean difference between the maximum and minimum attenuation values was significantly smaller in group 1 (41.3 +/- 16.8 H) than in group 2 (57.2 +/- 25.3 H). The renal arteries were assessable in all patients in both groups. CONCLUSION: This protocol of 50 mL of CM with a saline flush provides attenuation comparable to that obtained with the 100 mL of CM in aortoiliac 16-MDCT angiography.

Aged↗

PubMed2006

Lower tube voltage reduces contrast material and radiation doses on 16-MDCT aortography.

OBJECTIVE: The purpose of our study was to compare aortic CT angiography performed at a low tube voltage and reduced dose of contrast material with standard-voltage, standard-contrast-dose CT angiography. SUBJECTS AND METHODS: We evaluated 74 patients for aortic disease on MDCT angiography (collimation, 16 x 1.5 mm; beam pitch, 0.9). In 36 patients, we used the standard tube voltage (120 kVp) and a contrast dose of 100 mL (300 mg I/mL) (protocol 1), and in the remaining 38 patients we applied a reduced tube voltage (90 kVp) and a contrast dose of 40 mL (300 mg I/mL) (protocol 2). The patients' weights, CT attenuation of the aorta, visualization of the celiac axis and renal artery, and graininess and streak artifacts on transverse CT scans were evaluated and recorded for each data set. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were also measured. For statistical analysis, we used the two-tailed Student's t test and logistic regression; agreement between measurements recorded independently by two blinded reviewers was assessed using Cohen kappa statistics. RESULTS: In both protocols a negative correlation was seen between patient weight and CT attenuation. In three protocol 1 patients weighing more than 70 kg, CT attenuation was less than 200 H. No difference was seen between the two protocols with respect to mean attenuation of the aorta (p = 0.13) or visualization of the celiac axis and renal artery (p = 0.35 and 0.60, respectively). Although the SNR and CNR were significantly higher in protocol 1 than in protocol 2, qualitative evaluation of graininess and streak artifacts showed no statistically significant difference (p = 0.15 and 0.48, respectively). Interobserver agreement for quality assessments was within an acceptable range (kappa = 0.42-0.80). CONCLUSION: Low-contrast and low-voltage scans are appropriate for lighter patients (< 70 kg in body weight) with aortic disease. Moreover, this method is particularly valuable for follow-up studies of heavier patients (> 70 kg) with renal dysfunction.

Adult↗

PubMed2006

[Molecular epidemiology of tuberculosis by the use of IS6110 restriction fragment length polymorphism: a study from 2001 to 2003].

OBJECTIVE: To analyze the situation of tuberculosis infection by DNA fingerprinting in the middle and eastern part of Osaka, Japan. DESIGN: We performed IS6110 restriction fragment length polymorphism (RFLP) on 1200 isolates from tuberculosis patients who visited our hospital from January 2001 to December 2003. A cluster was defined as a series of isolates with more than 90% similarity by IS6110 RFLP and those with the same drug-susceptibility pattern. The isolates with fewer than six copies of IS6110 were considered to be clustered if the IS6110 RFLP patterns and the variable numbers of tandem repeats with 16 regions of ETR and MIRU "allele profile" were identical. RESULTS: The number of samples in incremental study periods was 422 in 2001, 817 between 2001 and 2002 and 1200 between 2001 and 2003. The percentage of clustered cases was 27.8% in 2001, 19.1% in 2002 and 19.5% in 2003. The cumulative percentage of clustered cases was 27.8% in the first year, 29.7% over two years and 32.6% over three years. The percentage of clustered cases of isolates with a drug resistance was significantly lower (25.0%) than that of drug susceptible isolates (33.7%). Next, we investigated the clustered cases by gender and age. The percentage of clustered cases with isolates from young males and females (0-19 years old) was 23.8%. In contrast, the percentage of clustered cases with isolates from 20-59 year-old females gradually decreased from 14.7% to 4.4%. Conversely, the percentage of clustered cases from young and middle aged male (20-59 years old) was higher (20.2%-32.4%) than that of females. CONCLUSION: The sharp increase in the cumulative cluster formation rate was curbed by the decline in the tuberculosis incidence rate in Osaka, Japan, after the first year of examination. We thought that this phenomenon suggests the success of the anti-tuberculosis measure in Japan.

Adult↗

PubMed2006

[Treatment outcome of patients with multidrug-resistant pulmonary tuberculosis during pregnancy].

PURPOSE: To know the treatment outcome of patients with multidrug-resistant tuberculosis (MDR-TB) during gestation. METHOD: Retrospective study of 3 cases of pregnant women, who were treated for MDR-TB with a regimen including pyrazinamide, ethambutol, para-aminosalicylic acid, cycloserine and amoxicillin-clavulanic acid. RESULT: All patients showed a good response to anti-tuberculosis chemotherapy without any serious adverse effect, and were culture-negative at the time of delivery. Two patients delivered vaginally at weeks 40, and one patient delivered surgically at weeks 38. All newborns were healthy, and their tuberculin skin tests and placental tissue examinations were negative for tuberculosis. CONCLUSION: MDR-TB can be successfully treated during pregnancy by using a regimen including effective second-line anti-tuberculosis drugs.

Adult↗

PubMed2005

Bovine lactoferrin is effective to suppress Helicobacter pylori colonization in the human stomach: a randomized, double-blind, placebo-controlled study.

Bovine lactoferrin (bLF) has antibacterial activity against Helicobacter pylori in vitro and is effective to suppress bacterial colonization in mice. The aim of our study was to evaluate the efficacy of orally administered bLF on H. pylori colonization in humans by a randomized, double-blind, placebo-controlled study. Fifty-nine healthy subjects positive for H. pylori infection were recruited. Subjects were randomized into two groups. The bLF group received bLF tablets at a dosage of 200 mg b.i.d. for a period of 12 weeks, and the control group received placebo tablets without bLF. The (13)C-urea breath test (UBT) was performed before, during, and at the end of administration, and again 4 weeks after administration. Positive response was defined as more than 50% decrease of the UBT value at the end of administration. Positive response was observed in 10 of 31 bLF-treated subjects (32.3%) and 1 of 28 control subjects (3.6%), indicating that the rate of positive response in the bLF group was significantly higher than that in the control group (bLF vs. control, P < 0.01). These results suggested that bLF administration is effective to suppress H. pylori colonization.

Adolescent↗

PubMed2005

Effects of orally administered bovine lactoferrin and lactoperoxidase on influenza virus infection in mice.

Milk contains a wide variety of host protective factors against infectious microbes. Among these protective factors, lactoferrin (LF) and lactoperoxidase (LPO) have been reported to exhibit antiviral activities as well as immuno-modulatory effects. In the present study, the effects of orally administered LF and LPO were assessed in a mouse influenza virus infection model. BALB/c mice were intranasally infected with 6.6x10(2) p.f.u. of influenza virus A/PR/8/34(H1N1). Bovine LF or LPO was administered once daily at a dose of 62.5 mg per mouse by gavage, starting 1 day before infection. Mice given LF or LPO showed a significantly lower lung consolidation score on day 6 after infection compared with the control mice that were given water instead. Concurrently, the number of infiltrated leukocytes recovered from bronchoalveolar lavage fluid (BALF) on day 6 was significantly lower in mice given LF or LPO. However, the virus yield in the BALF was not affected by these treatments. The serum level of IL-6, a pro-inflammatory cytokine, positively correlated with the lung consolidation score in each group and was significantly lower on day 6 in the mice given LPO. These results suggest the potential of oral administration of LF or LPO to attenuate pneumonia in influenza-virus-infected mice through the suppression of infiltration of inflammatory cells in the lung.

Administration, Oral↗

PubMed2005

Polymerase chain reaction--restriction fragment length polymorphism analysis of clarithromycin-resistant Helicobacter pylori infection in children using stool sample.

BACKGROUND: To analyze clarithromycin-resistant Helicobacter pylori infection in children, we developed a method of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis using stool samples. MATERIALS AND METHODS: Twenty-three children without significant upper abdominal symptoms were included (mean age 7.0 years). Of these, 18 and five were diagnosed as H. pylori-positive and -negative, respectively, by the H. pylori stool antigen test (HpSA). The DNA from the stool samples was purified using the QIAamp DNA Stool Minikit (QIAGEN). The PCR was performed on the purified DNA using oligonucleotide primers designed to amplify the 23S rRNA gene of H. pylori. The PCR products were reacted with restriction enzymes MboII, BceAI, and BsaI to detect mutations A2142G, A2142C, and A2143G, respectively. RESULTS: Sixteen of the 18 HpSA-positive samples were PCR-positive, and all five HpSA-negative samples were PCR-negative. Thus, the PCR had 89% sensitivity and 100% specificity, with 91% accuracy in reference to HpSA. Of the 16 PCR-positive samples, one and four were digested with MboII and BsaI, respectively, indicating 31% prevalence of CAM-resistance. CONCLUSIONS: We conclude that the PCR-RFLP using stool samples is a rapid and reliable method to noninvasively detect clarithromycin-resistant H. pylori infection in children. It may be useful before choosing regimens of H. pylori eradication.

Adolescent↗

PubMed2004

Administration of macrophage colony-stimulating factor mobilized both CD11b+CD11c+ cells and NK1.1+ cells into peripheral blood.

We attempted the phenotypic characterization of peripheral blood (PB) cells after daily administration of macrophage colony-stimulating factor (M-CSF) in mice. The number of CD11b+ cells was increased by M-CSF treatment (2- and 5-day injections). Notably, CD11bbrightCD11cdim, CD11b+CD11c+ and CD11b+CD80+ cells were significantly increased by 2-day treatment of M-CSF. On the other hand, the number of NK1.1+ cells was not changed by the 2-day treatment, but it was significantly increased by the 5-day treatment. However, the numbers of CD3+ and NK1.1+CD3+ cells were not changed by M-CSF treatment. Then, mononuclear cells (MNCs) were separated from the PB of mice treated with saline or M-CSF, and they were incubated with GM-CSF + IL-4 or IL-2. Compared with the saline-treated one (S-MNCs), the MNCs of M-CSF-treated mice (M-MNCs) showed strong proliferation by the GM-CSF + IL-4 stimulation. The MNCs could stimulate proliferation of allo-T cells in the mixed lymphocyte reaction (MLR), especially the M-MNCs showed strong reaction. On the other hand, the stimulation by IL-2 induced strong cell growth of MNCs. And M-CSF treatment enhanced this response. Furthermore, the M-MNCs (stimulated by IL-2 in vitro) exhibited greater cytotoxicity against Yac-1 cells than the S-MNCs. In conclusion, we found that administration of M-CSF mobilized CD11b+, CD11b+CD11c+, CD11b+CD80+, and NK1.1+cells into PB. And the injection of M-CSF facilitates the generation of dendritic and natural killer cells from PB cells in vitro. These results suggest that the mobilized cells may provide for application of immunotherapy.

Animals↗

PubMed2004

Protection against infections by oral lactoferrin: evaluation in animal models.

It has been reported previously that oral administration of lactoferrin (LF) provides some host-protective effects against infections, cancers, and inflammations. In this review, we focus on the effect of oral LF on various infectious diseases and discuss the mechanism as elucidated in animal models. In the case of infections occurring at sites other than the digestive canal, it is unclear whether oral LF is absorbed from the intestine and exerts its protective effect at the site of infection. In preterm human infants, neonatal pigs, and rats with colitis, it was reported that LF is detectable in various body fluids after oral administration. We could not detect the transport of oral bovine LF into the blood of adult rats without gastrointestinal illness using several techniques, suggesting that there is an extremely low level of transport of LF, if any. Orally administered LF may act at the oro-gastro-intestinal mucosa and aid the defense system against infections through a network of mucosal immunity and systemic immunity. Indeed, it is reported that oral LF increases the number of cells in the leukocyte subset and cytokine (IFN-gamma and IL-18) production in the intestinal mucosa of mice. Regarding systemic immunity, we have observed an increase of leukocyte number, cytokine (IFN-gamma, TNF-alpha, IL-12, and IL-18) production, and effector activity of macrophages in response to LF administration in several animal models. These enhanced immune responses may contribute to eradication of the pathogen, resolution of the symptoms, and maintenance of the homeostasis during infectious diseases.

Administration, Oral↗

PubMed2004

Effect of orally administered bovine lactoferrin on the immune response in the oral candidiasis murine model.

Therapeutic activity against oral candidiasis of orally administered bovine lactoferrin (LF), a multifunctional milk protein, was shown in a previous report using an immunosuppressed murine model. In the present study, the influence of orally administered LF on immune responses relevant to this therapeutic effect was examined. Because mice were immunosuppressed with prednisolone 1 day before and 3 days after the infection with Candida, the numbers of peripheral blood leukocytes (PBL) and cervical lymph node (CLN) cells were reduced. LF feeding prevented the reduction in the numbers of PBL on day 1 and CLN cells on days 1, 5 and 6 in the Candida-infected mice. The number of CLN cells of individual mice on days 5 and 6 was inversely correlated with the Candida c.f.u. in the oral cavity. Increased production of IFN-gamma and TNF-alpha by CLN cells stimulated with heat-killed Candida albicans on day 6 was observed in LF-treated mice compared with non-treated mice. Concanavalin A (ConA)-stimulated CLN cells from LF-treated mice also showed a significant increase in the production of IFN-gamma and IL12 on day 5 and a tendency for increased production of IFN-gamma and TNF-alpha on day 6. The levels of cytokine production by ConA-stimulated CLN cells on day 6 were inversely correlated with the Candida c.f.u. in the oral cavity. In conclusion, the alleviation of oral candidiasis by LF feeding in this model may correlate with the enhancement of the number of leukocytes and their cytokine responses in regional lymph nodes against Candida infection.

Adjuvants, Immunologic↗

PubMed2004

Oral lactoferrin prevents body weight loss and increases cytokine responses during herpes simplex virus type 1 infection of mice.

Lactoferrin (LF), a multifunctional milk protein, is known to inhibit in vitro infection by viruses such as herpes simplex virus type 1 (HSV-1). We evaluated the influence of LF feeding on the HSV-1 cutaneous infection of mice. Bovine LF was administered to mice and, after 10 d, the mice were infected with HSV-1. LF administration did not affect the viral clearance in the skin, but inhibited the appearance of skin lesions. LF prevented body weight loss and the decrease of splenocyte number associated with HSV-1 infection. LF increased the serum interleukin (IL)-18 level and splenocyte production of interferon-gamma and IL-12. These results suggest that LF feeding was not effective for eradication of the virus, but may contribute to the maintenance of homeostasis and the concomitant increases of cytokine responses during HSV-1 infection.

Administration, Oral↗

PubMed2004

No detectable transfer of dietary lactoferrin or its functional fragments to portal blood in healthy adult rats.

We investigated the transfer of dietary bovine lactoferrin (LF) and its functional lactoferricin (LFcin) B-containing fragments to the portal blood of healthy adult rats by using several techniques. After a single administration of (125)I-labeled LF, radioactive bands were detected in autoradioluminograms of the portal blood, but similar bands were also observed after the administration of [(125)I]NaI. Although ovalbumin was detected by ELISA at 3-18 ng/ml in the portal blood plasma after an overnight administration, no LF was detected (< or =1.5 ng/ml). The antibody-captured ovalbumin fragments, but not the LF fragments, were detected in the plasma by surface-enhanced laser desorption/ionization affinity mass spectrometry (SELDI affinity MS). We finally attempted to detect the LFcin B-containing fragments by SELDI affinity MS with on-chip LFcin B-conversion, but could not detect them (< or =1 ng/ml) in the portal blood after the LF ingestion. The level of LF or its functional fragments transferred to the portal blood was therefore extremely low, if any.

Aging↗

PubMed2004

The characteristics of people requesting HIV antibody tests at public health centers in Japan.

BACKGROUND: The epidemiologic features of those who requested to undergo the human immunodeficiency virus (HIV) antibody test at public health centers in Japan are still ambiguous, although as a group, they are probably at a high risk to be infected. METHODS: Between April 2001 and March 2002, 14,900 persons visited 131 public health centers that cooperated with this study in relation to the HIV antibody tests. A questionnaire was given to 8,972 persons who agreed to participate in the survey and 5,079 (56.6%) returned the form. Excluding those filled out by persons whose true intent in undergoing the test was the diagnosis of hepatitis C, 4,102 questionnaires were analyzed, individual characteristics examined, and first time visitors and repeaters were compared to assess their behavior and the reasons for of undergoing the test. RESULTS: There were 2,515 (61.3%) males and 1,587 (38.7%) females. The largest age group was composed of 25 to 29 year-olds. Repeaters accounted for 27.2% of all the males and 21.3% of all the females. Their main reason for undergoing the test was anxiety about having contracted an HIV infection through sexual contact with a person of the opposite sex. The proportion of those having sexual contact with males was significantly higher among male repeaters (14.1%) than first timers (8.0%). Among females, the proportion of those who had experience of sexual contact with many and unspecified males was significantly higher for repeaters (39.6%) than first timers (27.3%). CONCLUSION: It was evident from this study that repeaters exist among those who seek to be examined for possible contraction of HIV: they are characterized by risk-taking behavior in contracting an HIV infection through sexual contact.

AIDS Serodiagnosis↗