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Biomedical subjects

A Takahashi

Publications and source records attributed to A Takahashi.

At least 19 recordsLinked to original sources
PubMed2006

Choroidal blood flow in the foveal region in eyes with rhegmatogenous retinal detachment and scleral buckling procedures.

AIMS: To investigate changes in choroidal blood flow (ChBF) in the foveal region of the human eye with rhegmatogenous retinal detachment induced by scleral buckling. METHODS: ChBF was measured in the foveal region using laser Doppler flowmetry in patients with a rhegmatogenous retinal detachment and no macular involvement before and after scleral buckling. The ChBF ratio was evaluated (ChBF of the affected eye to ChBF of the fellow control eye) to minimise individual variations. RESULTS: Retinal reattachment was confirmed by 2 weeks after scleral buckling in all patients. The ChBF in the foveal region of the affected eyes did not differ from the fellow eyes before scleral buckling. The ChBF ratio significantly (p<0.05) decreased 2 and 4 weeks after scleral buckling compared with that before scleral buckling and returned to baseline 12 weeks after scleral buckling. CONCLUSIONS: The results suggest that ChBF in the foveal region transiently decreases after scleral buckling and recovers to the baseline level within 12 weeks in patients with a retinal detachment and no macular involvement.

Adult↗
PubMed2006

Fatal hepatitis B virus reactivation in a chronic myeloid leukemia patient during imatinib mesylate treatment.

Reactivation of chronic hepatitis B virus (HBV) infection in patients undergoing chemotherapy is well-documented, but reactivation during imatinib mesylate treatment has not been reported. This study reports a 54-year-old man, without prior liver dysfunction but with chronic HBV infection, in whom fatal HBV reactivation occurred during treatment of chronic myeloid leukemia (CML) with imatinib mesylate. He developed fulminant hepatitis followed by marked elevation of HBV DNA polymerase, probably from the lymphocytopenic and immunosuppressive status induced by imatinib mesylate. Imatinib mesylate is widely used to treat CML patients. Although therapy with imatinib mesylate is generally well tolerated, the case presented here suggests that viral reactivation should be considered, even when using imatinib mesylate to treat CML.

Antineoplastic Agents↗
PubMed2006

[C-reactive protein, white blood cell and body temperature following cardiovascular surgery, as predicting factors of postoperative infection].

The aim of this study is to clarify the relationship between CRP and postoperative infection after cardiovascular surgery. We had 5 cases of surgical site infection, and 3 cases of infective endocarditis (IE) among 57 patients selected for this study out of 405 patients who had undergone cardiovascular surgery from May 1995 to March 2005. CRP, WBC and body temperature (BT) were evaluated during 1 week after the operation. Our results showed not only that the mean value of CRP level in the 49 non-infection patients attained the peak on the 2nd or 3rd day after the operation (18.2 +/- 4.7 and 17.7 +/- 5.7 mg/dl), but also that each patient in this group showed the same pattern of CRP sequence. CRP in the 5 cases of postoperative infection showed different patterns from that in the non-infection group. CRP in 3 cases of valve replacement for IE showed significantly higher level than that in 16 cases of valve replacement without IE through 1 week after the surgery. WBC level in the non-infection group reached the peak just after the operation (11.3 +/- 4.4 x 10(3)/microl) and then decreased gradually during 1 week after the operation. WBC in the 3 cases of valve replacement for IE, did not show different sequence pattern from that in the 16 cases of valve replacement without IE. WBC in a case of postoperative mediastinal infection showed a similar pattern of sequence to that in the non-infection group although it showed a remarkably high level of CRP sequence through 1 week after the surgery. BT in the non-infection group became the lowest just after the operation and reached the peak 8 hours after the operation. It then decreased gradually during 1 week after the operation. Our study demonstrates that CRP sequence after the surgery might be useful to detect postoperative infection after cardiovascular surgery.

Aged↗
PubMed2005

Chronic toxicity and carcinogenicity of dietary administered ammonium sulfate in F344 rats.

Chronic toxicity and carcinogenicity studies of ammonium sulfate, used as a food additive in fermentation, were performed in male and female Fisher 344 rats at dietary concentrations of 0%, 0.1%, 0.6% and 3.0% in a 52-week toxicity study and 0%, 1.5% and 3.0% in a 104-week carcinogenicity study. Treatment with ammonium sulfate caused significant increase in kidney and/or liver weights in males and females of the 3.0% diet group, but no effects were found on survival rate, body weights, and hematological, serum biochemical or histopathological parameters at any dose levels in the chronic toxicity study. Regarding carcinogenicity, ammonium sulfate did not exert any significant influence on the incidences of tumors in any of the organs and tissues examined. It was concluded that the no observed adverse effect level of ammonium sulfate was the 0.6% diet, which is equivalent to 256 and 284 mg/kg b.w./day in males and females, respectively, and the compound is non-carcinogenic under the conditions of the study.

Administration, Oral↗
PubMed2005

Incidentally detected parafalcine chondrosarcoma.

Parafalcine chondrosarcoma is extremely rare, and may be difficult to differentiate preoperatively from falx meningioma. An 18-year-old woman presented with a parafalcine chondrosarcoma incidentally detected as a small lesion 2 years before admission, suggesting falx meningioma. Brain computed tomography and magnetic resonance imaging just before admission revealed the parafalcine lesion had increased by about nine times in volume during the last 2 years. Single-photon emission computed tomography (SPECT) after intravenous administration of both thallium-201 chloride ((201)TlCl) and N-isopropyl-p-[(123)I]iodoamphetamine ((123)I-IMP) demonstrated no abnormal uptake of either tracer. Histological examination revealed classic low-grade chondrosarcoma. Parafalcine chondrosarcoma should be considered at this site if relatively rapid growth is observed. SPECT using (201)TlCl and (123)I-IMP may be useful to discriminate parafalcine low-grade chondrosarcoma from meningioma or other tumours originating in this region.

Adolescent↗
PubMed2005

Wave-like appearance of diffuse pachymeningeal enhancement associated with intracranial hypotension.

Diffuse pachymeningeal enhancement on magnetic resonance (MR) imaging is important in identifying spontaneous and secondary intracranial hypotension (IH) [cerebrospinal fluid (CSF) hypovolemia] in patients with postural headache, because CSF pressure at lumbar puncture is variable. We examined the pachymeningeal enhancement pattern in patients with IH. MR imaging findings of pachymeningeal enhancement were examined before and after treatment in seven consecutive patients with spontaneous IH and one patient with IH after lumbar puncture. Diffuse non-nodular dural enhancement was observed in all patients. Characteristic thick, uninterrupted, enhancement was observed, mainly in the dura of the frontal, temporal, and retroclival regions, and the tentorium. Thin and uninterrupted, or partially interrupted, enhancement was observed, mainly in the parieto-occipital region and cerebellar convexity. Curved linear enhancement was observed along the calvarium of all patients. A wave-like appearance, a clear pattern of dural unevenness parallel to the brain, was detected in the frontal and temporal regions, near the base, in all patients. A wave-like appearance, especially in the frontal and temporal base, may be a characteristic MR imaging indicator of IH.

Adult↗
PubMed2005

Apoptosis induced by high-LET radiations is not affected by cellular p53 gene status.

To learn more about the biological effects of high-linear energy transfer (LET) radiations, we examined radiation-induced apoptosis in response to high-LET radiations in cells with wild-type, mutated and null p53 gene. Three human lung cancer cell lines were used. These lines had identical genotypes, except for the p53 gene. Cells were exposed to X-rays or high-LET radiations (13 - 200 keV microm(-1)) using different nuclei ion beams. Cellular radiation sensitivities were determined with the use of colony-forming assays. Apoptosis was detected and quantified using Hoechst 33342 staining with fluorescence microscopy. It was found that (1) there was no significant difference in cellular sensitivity to high-LET radiation (>85 keV microm(-1)), although the sensitivity of wild-type p53 cells to X-rays was higher than that of mutated p53 or p53-null cells; (2) X-ray-induced apoptosis at higher frequencies in wild-type p53 cells when compared with mutated p53 and p53-null cells; and (3) Fe beams (200 keV microm(-1)) induced apoptosis in a p53-independent manner. The results indicate that high-LET radiations induces apoptosis in human lung cancer cells in a manner that does not seem to depend on the p53 gene status of the cells.

Apoptosis↗
PubMed2005

Serum prorenin levels and diabetic retinopathy in type 2 diabetes: new method to measure serum level of prorenin using antibody activating direct kinetic assay.

AIM: To investigate the serum levels of prorenin and its correlation with the severity of diabetic retinopathy (DR). METHODS: 248 patients with diabetes and 108 control subjects were divided into four groups: no-DR (n = 146), no proliferative diabetic retinopathy (no-PDR) (n = 78), PDR (n = 24), and controls (n = 108). Serum levels of prorenin from all subjects were measured using the new antibody activating direct kinetic (AAD-PR) assay. The serum prorenin levels were compared among the groups. RESULTS: The serum levels of prorenin in the control, no-DR, no-PDR, and PDR groups, respectively, were 109.1 (66.1), 194.6 (160.4), 271.5 (220.3), and 428.4 (358.4) pg/ml (mean (SD)). Prorenin in the PDR group was remarkably high compared with the control and no-DR groups (p<0.0001) and with the no-PDR group (p = 0.002). Serum levels of prorenin increased with increasingly severe retinopathy. No correlation was found between the prorenin level and the duration of disease or HbA(1c). CONCLUSIONS: The serum levels of prorenin in patients with PDR were found to be markedly high using the AAD-PR assay. Increased levels of prorenin in diabetes may have an important role in the pathogenesis of DR.

Antibodies↗
PubMed2005

Association of a polymorphism of the transforming growth factor-beta1 gene with cerebral amyloid angiopathy.

BACKGROUND: A recent study showed that transforming growth factor-beta1 (TGF-beta1) induces amyloid-beta deposition in cerebral blood vessels and meninges of a transgenic mouse model of Alzheimer's disease (AD), and that TGF-beta1 mRNA levels are correlated with cerebral amyloid angiopathy (CAA) in human AD brains. A T/C polymorphism at codon 10 in exon 1 of the TGF-beta1 gene has been reported to be associated with the serum TGF-beta1 concentration. We investigated whether the TGF-beta1 polymorphism is associated with the risk of CAA. METHODS: The association between the severity of CAA and the T/C polymorphism at codon 10 in exon 1 of the TGF-beta1 was investigated in 167 elderly Japanese autopsy cases, including 73 patients with AD. The apolipoprotein E (APOE) genotype was also determined. RESULTS: The genotypes (TT/ TC/ CC) were associated with the severity of CAA significantly in all patients (p = 0.0026), in non-AD patients (p = 0.011), and APOE non-epsilon4 carriers (p = 0.0099), but not in AD patients or APOE epsilon4 carriers. The number of the T alleles positively correlated with the severity of CAA in all patients (p = 0.0011), non-AD patients (p = 0.0026), and APOE non-epsilon4 carriers (p = 0.0028), but not in AD patients or APOE epsilon4 carriers. The polymorphism was not significantly associated with AD. CONCLUSIONS: Our results suggest that the polymorphism in TGF-beta1 is associated with the severity of CAA, especially in non-AD patients and APOE non-epsilon4 carriers.

Aged↗
PubMed2005

Osteoid osteoma treated with computed tomography-guided percutaneous radiofrequency ablation: a case series.

The nidi of osteoid osteoma are small and difficult to identify precisely; this can necessitate substantial resection of the surrounding normal bone. We applied percutaneous, image-guided radiofrequency ablation to treat 5 patients with osteoid osteoma. The precise location of each nidus was determined using a 3-mm-thick spiral computed tomographic scan. The most appropriate needle pathway was selected to avoid major neural and vascular structures. A 14-gauge core needle was introduced into the nidus and then exchanged for a 17-gauge straight rigid electrode with a 1-cm exposed tip to heat the lesion to 90 degrees centigrade for 5 minutes. Four of the 5 patients were discharged on the day after surgery without any external supports, and were pain-free after a few days. The remaining patient had a pes equinus contracture induced by the penetration of the calf muscles through a posterior approach but was fully recovered 6 days later. The mean follow-up period was 20.6 months. No recurrences or late complications were observed in this series. This case series shows that the computed tomography-guided percutaneous radiofrequency ablation is a simple, minimally invasive, and highly effective technique for the treatment of osteoid osteoma.

Adult↗
PubMed2005

Expression of prolactin-releasing peptide and prolactin in the euryhaline mudskippers (Periophthalmus modestus): prolactin-releasing peptide as a primary regulator of prolactin.

Prolactin (PRL)-releasing peptide (PrRP) is a strong candidate stimulator of pituitary PRL transcription and secretion in teleosts. However, the role in control of extrapituitary PRL expression is unclear even in mammals. To study the possible presence of PrRP-PRL axes not only in the brain-pituitary but also in peripheral organs, the expression patterns of PrRP, PRL and growth hormone (GH) were characterized in amphibious euryhaline mudskippers (Periophthalmus modestus). PrRP mRNA is abundantly expressed not only in the brain but also in the liver, gut and ovary, while less abundant expression was also detected in the skin and kidney. Corresponding to the distribution of PrRP mRNA, PRL mRNA was also detectable in these organs. During adaptation to different environments, the changes in mRNA levels of PrRP paralleled those in PRL in the brain-pituitary, liver and gut in an organ-specific manner. Brain PrRP mRNA and the pituitary PRL mRNA increased under freshwater and terrestrial conditions (P < 0.05); expression of PrRP and PRL in the gut of freshwater fish was higher (P < 0.05) than those in sea-water fish although there were no changes in fish kept out of water; no significant change was seen in the liver. Expressions of GH were not correlated with PrRP. In the gut, PrRP and PRL appear to be co-localized in the mucosal layer, especially in the mucous cells. Thus, PrRP may also be a local modulator of extrapituitary PRL expression and the PrRP-PRL axes in various organs may play an organ-specific role during environmental adaptation.

Animals↗
PubMed2005

Clinicopathological features and the prognosis of IgA nephropathy in Japanese children on long-term observation.

AIMS: Clinicopathological features were investigated to clarify the ultimate prognosis and prognostic indicators for patients with IgA nephropathy in Japanese children. METHODS: We evaluated the outcomes of 181 patients in whom IgA nephropathy was diagnosed before the age of 15 years since September 1979 and followed-up at least for three years with regard to clinical data at the onset of symptoms and renal histologic data. RESULTS: After mean follow-up of 7.3 years from onset, 91 patients of 181 (50.3%) were in clinical remission at the last examination, 24 (13.2%) had isolated hematuria, 59 (32.6%) had hematuria and proteinuria. Eighteen of 59 (9.9%) had proteinuria more than 1 g per 24 hours. Hypertension was observed in 12 cases and 7 (3.9%) developed end-stage renal disease. Except 7, no patient had reduced renal function and elevated serum creatinine at the final follow-up. Predicted renal survival rate from onset was 92.3% at 10 years and 89.1% at 20 years. In multivariable analysis, age at onset and chronic changes of tubulointerstitium were associated with poor outcome. CONCLUSIONS: Of 181 children with IgA nephropathy, 50% regressed, remaining 46% had hematuria and/or proteinuria and 4% of patients lapsed into end-stage renal disease. Our results indicate that childhood IgA nephropathy has a benign course and the risk for end-stage renal disease is lower than that of adults. Age at onset and tubulointerstitial lesions were the strong predictors of a progressive course of childhood IgA nephropathy.

Adolescent↗
PubMed2005

[Treatment results of pancoast tumor].

To study the clinical characteristics, treatment modalities, and outcome of patients with Pancoast tumors who underwent surgery over 11-year period. From January 1994 to May 2005, 13 patients (12 men, 1 woman) with Pancoast tumor and histology of non-small cell lung cancer underwent surgical resection. Nine patients were received induction therapy (8 chemoradiation, 1 radiation only), and there were no treatment-related deaths. Twelve lobectomies, 1 pneumonectomy, and none of wedge resections or partial resection were performed. The number of ribs resected ranged from 2-6 (median 2.8). Chest wall reconstruction was performed in 2 patients, total vertebrectomy in 2, bronchoplasty in 2, and pulmonary arterioplasty in 1. Twelve of 13 patients (92.3%) had a complete resection. Pathologic stages were IB, IIB, IIIA and IIIB in 1, 7, 2, and 1, respectively, and pathologic complete responses was noted in 1. After a median follow-up of 34 months, the 3-year survival was 78.6% for all 13 patients and 85.7% for patients who had a complete resection. It is thought that induction chemoradiation for Pancoast tumors have potential to be able to become the treatment strategy in the future.

Adult↗
PubMed2004

Penguin-mounted cameras glimpse underwater group behaviour.

Marine birds and mammals spend most of their lives in the open ocean far from human observation, which makes obtaining information about their foraging behaviour difficult. Here, we show, by use of a miniaturized digital camera system, the first direct evidence (to our knowledge) of underwater group behaviour in free-ranging penguins. Penguins swim closely accompanied by other bird(s) during 24% of their possible foraging dives. This finding confirms that such miniaturized camera technology has broad applicability for advancing our knowledge about the previously unknown social interactions of marine animals at depth.

Animals↗
PubMed2004

Basic characteristics of the radio imaging method for biomedical applications.

The radio imaging method (RIM), a technology used practically for geophysical surveys, was applied to biomedical measurements. The characteristics of a subject between a pair of simple loop antennas were measured by using a feeble electromagnetic wave of low frequency. Water distribution inside the human body was expected to be measured, as well as the original method imaged mineral distributions. In geophysical surveys, finer resolution is provided than a wavelength of the electromagnetic wave. This was also expected for biomedical measurements. An acrylic water tank was used as a phantom of the abdominal portion of the human body, and basic measurements were performed with the phantom. The inner tank of the phantom, whose cross section was 6 x 8 cm, was detected by the method when the frequency was 54 MHz or the wavelength was nearly 6 m in free space. The resolution provided by the experiment suggested that the proposed method was effective even if the wavelength was longer than the dimensions of the targeted area. The advantage of the method is simplicity, economy and safety. The authors are looking for specific applications for example, a urination sensor or a vital monitor for in-home care, where the strong points of the method are suitable.

Abdomen↗