Biomedical subjects

Aki Ito

Publications and source records attributed to Aki Ito.

5 recordsLinked to original sources

PubMed2003

Distribution of rat organic anion transporting polypeptide-E (oatp-E) in the rat eye.

PURPOSE: To examine the protein and mRNA expression levels of the recently cloned rat multifunctional Na+-independent organic anion transporting polypeptide (rat oatp-E), which is involved in the transport of thyroid hormone in the rat, the distribution and function of this transporter were investigated in the retina. METHODS: Real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed with gene-specific primers for oatp-E in rat ocular tissues. Western blot analysis was performed by raising a specific antibody against oatp-E in rat ocular tissues. Immunohistochemistry was performed with a specific antibody for oatp-E in paraffin sections of rat eyes. The expression of oatp-E in isolated and cultured rat retinal pigment epithelial (RPE) cells was confirmed by RT-PCR, Western blot analysis, and immunohistochemistry. In addition, oatp-E function was analyzed in cultured rat RPE cells by measuring the uptake of triiodothyronine (T3), which is a known substrate for oatp-E. RESULTS: Using real-time quantitative RT-PCR, oatp-E mRNA was detected, in order of highest to lowest concentration, in the rat retina, cornea, and ciliary body-iris. A single band for oatp-E was observed by Western blot analysis in the rat brain, retina, cornea, and ciliary body-iris. oatp-E immunostaining was predominantly expressed in the corneal epithelium, in the pigmented and nonpigmented epithelium of the ciliary body, and in the iris of the rat eye. In the rat retina, intense immunostaining was detected in the RPE, inner and outer nuclear layers, ganglion cell layer, and nerve fiber layer. In addition, oatp-E immunoreactivity in cultured rat RPE cells was expressed in the cell membrane and cytoplasm of RPE cells, a finding that was also confirmed by RT-PCR and Western blot analysis. RPE cells, which were shown to express high levels of oatp-E, transported T3 in a saturable and dose-dependent manner. Moreover, this uptake was significantly inhibited by sulfobromophthalein (BSP), an inhibitor of oatp, suggesting that oatp-E may in part contribute to this uptake. CONCLUSIONS: Results from the present study revealed that rat oatp-E is localized mainly to the corneal epithelium, ciliary body, iris, and retina. Furthermore, the findings appear to suggest that transport of T3 in the RPE may have a functional role for organic anion (i.e., thyroid hormone) transport in the rat eye.

Animals↗

PubMed2003

Brainstem infarction presenting with neurogenic stuttering.

We reported a sixty-year-old man who developed acquired stuttering after a brainstem infarction. Infarctions were detected in the midbrain and upper pons. Neurogenic stuttering of this patients indicated that the midbrain and upper pons could be lesion sites responsible for acquired stuttering. We speculated that the reticular network extending from the brainstem to the frontal cortices, and the periaqueductal gray matter could be closely related regions generating neurogenic stuttering.

Brain Stem Infarctions↗

PubMed2002

Endotoxin removal by direct hemoperfusion with an adsorbent column using polymyxin B-immobilized fiber ameliorates systemic circulatory disturbance in patients with septic shock.

Direct hemoperfusion (DHP) with an adsorbent column using polymyxin B-immobilized fiber (PMX-F) has been shown to improve the state of shock in patients with septic shock. However, no evidence has been presented for a direct link between endotoxin removal by DHP with PMX-F and improvement in septic shock. We retrospectively analyzed clinical profiles of 24 patients with septic shock (16 patients, gram-negative; 8 patients, non-gram-negative septic shock) who underwent DHP with PMX-F. Patients with gram-negative septic shock were characterized by hyperdynamic circulation. DHP with PMX-F reduced blood endotoxin concentrations and ameliorated shock, with an improvement in hyperdynamic circulation in patients with gram-negative septic shock. Mean arterial pressure also was elevated after therapy in patients with non-gram-negative septic shock, but systemic hemodynamics were unaffected. Regardless of the causative microorganism, patients with endotoxemia (blood endotoxin level > 10 pg/mL) showed hyperdynamic shock, and DHP with PMX-F reduced blood endotoxin levels and ameliorated hyperdynamic circulation, whereas patients without endotoxemia showed features of shock without hyperdynamic circulation, and DHP with PMX-F ameliorated shock without affecting cardiac performance. In patients with gram-negative septic shock, blood endotoxin concentration correlated positively with cardiac output and negatively with systemic vascular resistance before DHP therapy. Reduction in blood endotoxin concentration by DHP therapy positively correlated with the reduction in cardiac output. Our findings indicate that the improvement in hyperdynamic circulation was related directly to endotoxin removal by the PMX-F column, and endotoxin has an important role in the development of hyperdynamic circulation in patients with gram-negative septic shock.

Adsorption↗

PubMed2002

Distribution of organic anion-transporting polypeptide 2 (oatp2) and oatp3 in the rat retina.

PURPOSE: To examine the expression of multifunctional Na(+)-independent organic anion-transporting polypeptides, termed oatp1, oatp2, and oatp3, involving the transport of thyroid hormone in the rat retina at the protein and mRNA levels. METHODS: Northern blot analysis was performed using oatp1, -2, and -3 cDNAs. Reverse transcription-polymerase chain reaction (RT-PCR) was also performed using gene-specific primers for oatp1, -2, and -3. mRNA distribution of these oatps in the rat retina was examined by in situ hybridization. Western blot analysis and immunohistochemistry were also performed by raising specific antibodies against oatp2 and -3. RESULTS: Northern blot analysis showed that the mRNAs for oatp2 and -3 were expressed in the rat retina and retinal pigment epithelium (RPE). Amplified cDNA products by RT-PCR for oatp2 and -3 were also detected in the rat retina-RPE. In contrast, no specific band for oatp1 was detected by Northern blot analysis or RT-PCR. By in situ hybridization, oatp2-specific mRNA signals were seen in the RPE and inner nuclear layer, whereas the oatp3 mRNA signal was localized to the ganglion cell. At the protein level, a single band for oatp2 and -3 proteins was detected in the rat retina-RPE by Western blot analysis. Immunohistochemistry revealed that oatp2 immunostaining was predominantly expressed at the apical surface of the RPE. Weak immunostaining for oatp2 was also seen in the inner nuclear layer and the ganglion cell layer. In contrast, apparent immunostaining for oatp3 was seen in the nerve fiber layer, ganglion cell layer, inner plexiform layer, and outer aspect of the inner nuclear layer. In addition, oatp3 immunostaining was detected predominantly in the optic nerve fiber. CONCLUSIONS: These results reveal that oatp2 is localized mainly in the RPE, suggesting a role for organic anion transport in this specialized ocular tissue. In contrast, oatp3 is localized mainly in optic nerve fibers, suggesting that oatp3 is a specific transporter in the visual nervous system. In conclusion, these data suggest that oatp2 and -3 may be involved in the transport of thyroid hormone in the rat retina.

Animals↗

PubMedDate not supplied

Clinical profiles and outcomes of end-stage renal failure patients with late initiation of renal replacement therapy based on uremic symptoms under intensive renoprotective therapies.

AIM: This study describes the clinical profiles and outcomes of renal failure patients with late initiation of renal replacement therapies (RRT) based on uremic symptoms under intensive treatment prior to the start of RRT (IT). METHODS: Thirteen patients (male 10, female 3) with end-stage renal disease who preferred to wait for the initiation of RRT until uremic symptoms appeared regardless of serum creatinine (s-Cr) and 24-hour creatinine clearance (24-hour Ccr) were chosen. All patients received IT including a low-protein diet, antihypertensive drugs including enalapril, erythropoietin and others to prevent and manage uremic states until the initiation of RRT. Clinical findings at the initiation of RRT and the outcomes after the start of RRT were examined. RESULTS: RRT was initiated 23.6 +/- 16.9 months after IT without any complication in all patients when mild uremic symptoms appeared. Uremic symptoms, blood pressure, serum albumin, potassium, calcium and urinary Cr excretion were well controlled except inorganic phosphate, hemoglobin and cardiac size. 24-hour Ccr and s-Cr were 3.4 +/- 0.7 ml/min and 17.4 +/- 3.8 mg/dl at initiation of RRT. The outcomes of all the patients were all well during chronic RRT. CONCLUSION: Intensive treatment prior to the start of RRT can diminish uremic symptoms and complications so that RRT might be initiated safely and with fewer problems, even in the face of lower 24-hour Ccr and markedly higher s-Cr.

Antihypertensive Agents↗