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Biomedical subjects

N Kanai

Publications and source records attributed to N Kanai.

At least 55 records · Page 3Linked to original sources
PubMed1996

Immunologic distribution of an organic anion transport protein in rat liver and kidney.

A Na(+)-independent organic anion transport protein was recently cloned from rat liver using a Xenopus laevis oocyte expression system [E. Jacquemin, B. Hagenbuch, B. Stieger, A.W. Wolkoff, and P.J. Meier, Proc. Natl. Acad. Sci. USA 91: 133-137, 1994]. Although expression of this protein is sufficient for cells to transport the organic anion bromosulfophthalein, little is known about its cell biology or biochemical characteristics. Northern blot analysis performed under high-stringency conditions revealed hybridization with RNA only from liver and kidney; transcripts appeared the same in these two organs. Within kidney, hybridization was greatest when RNA extracted from the outer medulla was used. Immunoblot analysis revealed that in liver, the transporter was enriched in 0.1 M Na2CO3-extracted membranes and sinusoidal plasma membrane preparations, consistent with its being an integral membrane protein. This 80-kDa protein migrated as a 65-kDa protein after treatment with N-glycanase. Immunomorphological examination of liver revealed basolateral plasma membrane localization. In 0.1 M Na2CO3-extracted membranes of kidney, the transporter migrated as an 83-kDa protein on nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). On reduction, it resolved into peptides of 33 and 37 kDa. SDS-PAGE migration of the liver protein was unaffected by reduction. Immunomorphological examination of kidney revealed apical plasma membrane localization in the S3 segment of the proximal tubule of the outer medulla. Differential processing and trafficking of this transporter in liver and kidney may have important functional and regulatory consequences.

Adenosine Triphosphate↗
PubMed1996

Transient expression of oatp organic anion transporter in mammalian cells: identification of candidate substrates.

The cDNA for the rat liver organic anion-transporting polypeptide "oatp" has been shown to encode transport of bromosulfophthalein (BSP) and bile salts in Xenopus oocytes (E. Jacquemin, B. Hagenbuch, B. Stieger, A. W. Wolkoff, and P. J. Meier. Proc. Natl. Acad. Sci. USA 91: 133-137, 1994). Because oatp mRNA is expressed strongly in the kidney, we sought to determine whether renal oatp might play a role in the known secretion of a large variety of organic anions by the kidney. We transiently expressed a full-length oatp cDNA, cloned in pSPORT, in HeLa cell monolayers using the recombinant vaccinia virus vtf7-3. We tested an array of organic anions as candidate substrates by determining their ability to compete with tracer BSP for transport. HeLa cell monolayers transfected with the oatp cDNA transported tracer BSP and taurocholate at rates substantially higher than monolayers transfected with a control plasmid. Thus good expression can be obtained with the vaccinia-HeLa system using a standard plasmid cloning vector. BSP transport varied as a function of the medium albumin, ionic conditions, and pH in a fashion similar to that in Xenopus oocytes. Several organic anions known to be secreted by the classic secretory pathway, including p-aminohippurate (PAH), phenol red, and indigo carmine (10 microM) failed to inhibit oatp-mediated BSP transport. Direct testing using tracers revealed no oatp-mediated transport of sulfate, urate, PAH, several eicosanoids, or unconjugated or conjugated bilirubin. On the other hand, BSP transport was inhibited by approximately 50% by 10 microM corticosterone sulfate, spironolactone, and several other steroids. We conclude that the functional properties of oatp expressed in the HeLa cell/vaccinia transient expression system are comparable to those following expression in Xenopus oocytes and that steroids are likely to represent high-affinity endogenous oatp substrates. The latter hypothesis is addressed in greater detail in a companion paper.

Anion Transport Proteins↗
PubMed1996

Estradiol 17 beta-D-glucuronide is a high-affinity substrate for oatp organic anion transporter.

Although substantial evidence indicates that estradiol-17 beta (E2) is conjugated to the glucuronide in the kidney and then excreted by a direct tubular secretory route and that the liver transports E2 glucuronides via carrier-mediated mechanisms, the transporters involved in these processes have not been identified. The so-called "organic anion-transporting polypeptide" (i.e., oatp) has a number of known substrates, including bromosulfophthalein (BSP) and taurocholic acid (TCA) (E. Jacquemin, B. Hagenbuch, B. Stieger, A. W. Wolkoff, and P. J. Meier. Proc. Natl. Acad. Sci. USA 91: 133-137, 1994). In a companion study, we determined that steroid hormones represent a class of hormones that interact strongly with oatp when the latter is transiently expressed in vitro. Here, we studied more extensively steroids and steroid anion conjugates as candidate oatp substrates. In HeLa cell monolayers transfected with a full-length oatp cDNA, [3H]estradiol 17 beta-D-glucuronide ([3H]E2-17G) was transported with a signal-to-noise ratio of 15:1 over that of monolayers transfected with a control plasmid. The affinity of oatp for [3H]E2-17G was significantly higher than that for TCA (K(m) of 3 microM vs. 27 microM, respectively). In contrast to E2-17G, unconjugated estradiol (E2) was not significantly transported by oatp. Several unconjugated steroids and anionic steroid conjugates were tested for their ability to compete with tracer E2-17G for oatp-mediated transport. Conjugation at the 17 or 3 position with the anion of a strong acid (sulfate) resulted in a greater degree of inhibition of tracer E2-17G transport than did conjugation at the 17 or 3 position with an uncharged group (acetate), suggesting that the strength of the negative charge at these positions is an important determinant of the affinity of a given steroid conjugate for oatp. We conclude that the preferred substrates for oatp are steroids with a strong 17- or 3-position anionic group. Since steroid sulfotransferases and glucuronosyltransferases are expressed in the proximal tubule, as is oatp, the transporter may serve as an apical exit pathway for steroids following their conjugation within the tubule cell.

Anion Transport Proteins↗
PubMed1996

Regulation of renal oatp mRNA expression by testosterone.

A recently cloned cDNA encodes the so-called "organic anion-transporting polypeptide" (i.e., oatp), which is expressed in rat liver and in the kidney S3 proximal tubule. functional characterization of the cloned transporter indicates that estradiol 17 beta-D-glucuronide is a major substrate. Because the urinary excretion of glucuronidated steroids differs between males and females, we hypothesized that renal oatp expression may be under sex hormone control. Total RNA was isolated from male or female kidneys and probed with a digoxigenin-labeled oatp antisense riboprobe. Expression of oatp mRNA expression was quantitated by densitometry from Northern blots. Male kidneys expressed at least six distinct oatp transcripts (approximately 4.0, 3.2, 2.9, 2.6, 1.7, and 1.2 kb). Of these, the 3.2-kb band was consistently the strongest. In female rats, renal oatp mRNA expression was markedly less, such that only the 3.2-kb band was consistently detectable. Administering testosterone to female rats increased, and administering estradiol (E2) to male rats decreased, the steady-state levels of renal oatp mRNA. Gonadectomized male and female rats, as well as adrenalectomized male rats, were given pharmacological hormone replacement (testosterone, E2, or dexamethasone, respectively) by subcutaneous osmotic minipump. Castration of male rats produced a dramatic drop in the steady-state level of all six renal oatp transcripts. These were returned to normal by testosterone replacement. In contrast, there was no regulation of hepatic oatp mRNA expression by testosterone. Renal oatp mRNA expression in female rats was mildly increased by oophorectomy. Administration of E2 to oophorectomized females moderately suppressed renal oatp mRNA expression. Adrenalectomy produced a small decrease in oatp expression, but dexamethasone replacement failed to return expression to normal. We conclude that renal oatp mRNA expression is under strong (stimulatory) testosterone control and perhaps weaker (inhibitory) estrogen control. We speculate that this regulation of renal oatp expression is important in modulating the renal tubular secretion of conjugated E2.

Adrenalectomy↗
PubMed1996

Craniospinal arachnoid cyst: case report.

We encountered a rare case of craniospinal arachnoid cyst. A 54-year-old woman was admitted to our clinic for headache, posterior nuchal pain, and vomiting, which had started one month before. On admission she was drowsy, and neurological examination revealed papilledema and prompt deep tendon reflexes bilaterally. T1 weighted images of MRI revealed a homogeneous, round, low density mass in the left cerebellar hemisphere which extended down on the dorsal side of the spinal cord to the level of C2. It was high intensity on T2 weighted images and was not enhanced by Gd-DTPA. The fourth ventricle was compressed and obstructed and hydrocephalus was observed. An operation was performed via a left suboccipital craniectomy with C1 laminectomy. A large cyst was located in the left cerebellar hemisphere, and it extended into the spinal canal down to the C2 level where the cyst compressed the spinal cord right-anteriorly. The content of the cyst was xanthochromic fluid. After the removal of as much of the cyst as possible, the flattened tonsil was seen just dorsal to the medulla. The cyst extended into the cerebellar hemisphere via the widened fissura secunda. The arachnoid of the cisterna magna was incised and communication between the cisterna magna and the cyst was made. The cyst was markedly reduced on the following day, and disappeared on the 50th postoperative day. The patient was discharged without neurological deficit. Pathological diagnosis of the cyst wall in the cerebellum was that the molecular layer of the cerebellar cortex was covered by arachnoid membrane, which indicated arachnoid cyst. Five such cases have been reported apart from this one. The therapy is the extirpation of the cyst wall and making communication between the arachnoid cyst and the subarachnoid space. The etiology of craniospinal arachnoid cyst is not well known but postoperative prognosis is good.

Arachnoid Cysts↗
PubMed1996

[Tonoko pneumoconiosis with deposition of titanium].

A 56-year-old man had worked as a furniture painter and had been exposed to tonoko polishing powder for 30 years. He had complained of dyspnea on exertion for 7 years, and was admitted to our hospital in 1991. A chest X-ray film revealed large opacities and emphysematous changes in both lung fields. Tonoko pneumoconiosis was diagnosed after transbronchial lung biopsy. Home oxygen therapy was given because of progressive hypoxemia, but the patient died of respiratory failure. At autopsy, examination of the lungs showed severe emphysematous changes, and collapse of alveoli. Many gray masses resembling coating cement were seen especially in the upper lobes. Microscopical examination showed that the large opacities were composed of hyaline nodules, similar to silicotic nodules, with anthracosis. Scanning electron microscopy with X-ray microanalysis revealed a high concentration of titanium in the gray mass. A low dose of titanium would not be expected to induce fibrotic changes in the lung, but a high dose and long-term exposure might have that effect. Titanium contained in paint might have exacerbated tonoko pneumoconiosis in this patient.

Dust↗
PubMed1995

Identification and characterization of a prostaglandin transporter.

Carrier-mediated prostaglandin transport has been postulated to occur in many tissues. On the basis of sequence homology, the protein of unknown function encoded by the rat matrin F/G complementary DNA was predicted to be an organic anion transporter. Expression of the matrin F/G complementary DNA in HeLa cells or Xenopus oocytes conferred the property of specific transport of prostaglandins. The tissue distribution of matrin F/G messenger RNA and the sensitivity of matrin F/G-induced prostaglandin transport to inhibitors were similar to those of endogenous prostaglandin transport. The protein encoded by the matrin F/G complementary DNA is thus preferably called PGT because it is likely to function as a prostaglandin transporter.

Amino Acid Sequence↗
PubMed1995

Proliferative activity of mast cells in allergic nasal mucosa.

The proliferative activity of mast cells in the nasal mucosae of allergic (n = 14) and non-allergic (n = 18) rhinopathic patients was studied by a sequential double immunohistochemistry using anti-proliferating cell nuclear antigen (PCNA) and anti-tryptase antibodies. Two hundred to 300 tryptase-positive cells (mast cells) were studied in each allergic nasal epithelium. In case of non-allergic nasal mucosa, only a few mast cells existed in the epithelial layer. The total number of mast cells which we could detect in all patients was 168 cells. One of these cells contained PCNA. Three hundred to 500 mast cells were studied in each subepithelial layer and deep layer of lamina propria of both diseases. PCNA-positive mast cells were observed in the nasal epithelia of 10 allergic patients. In the subepithelial layer, PCNA-positive mast cells were observed eight allergic patients and four non-allergic patients, respectively. In the deep lamina propria, PCNA-positive mast cells were observed in a few patients with both diseases. The percentage of PCNA-positive mast cells of all mast cells each area ranged from 0 to 1.7%. The incidence of PCNA-positive mast cells was statistically higher in the allergic epithelium and subepithelial layer than in the deep layer of lamina propria. Moreover, that of PCNA-positive mast cells in the subepithelial layer was higher in allergic than in non-allergic nasal mucosa. Our results suggest that mast cell proliferation may contribute to the number of mast cells in the nasal epithelium and subepithelial layer of allergic patients.

Adolescent↗
PubMed1995

p53 mutation in carcinomas arising in ovarian cystic teratomas.

Carcinomas arising in mature cystic teratomas of the ovaries from nine women were examined for the presence of p53 mutations. The nine tumors comprised six squamous cell carcinomas, one squamous cell carcinoma in situ, one undifferentiated small cell carcinoma, and one mucoepidermoid carcinoma. Abnormal nuclear accumulation of the p53 protein was observed in four of the tumors. Genomic DNA was extracted from formalin-fixed, paraffin-embedded tissue blocks and subjected to polymerase chain reaction (PCR) for specific amplification of the p53 gene exons 5-8, followed by direct chemiluminescence sequencing analysis. A frameshift mutation in exon 8 (codon 278, CCT > del T; stop at codon 344) was detected in one poorly differentiated squamous cell carcinoma. The samples were also evaluated for the possible association of 'benign' and 'malignant' types of human papillomavirus (HPV) by PCR using universal primer sets. None of the samples contained detectable HPV genome. These data suggest that p53 mutations are relatively uncommon in secondary carcinomas developing in ovarian dermoid cysts, although the number of samples studied was admittedly small.

Adult↗
PubMed1995

[A case of intracranial malignant meningioma with extraneural metastases].

A case of intracranial malignant meningioma with remote metastases to the bones is reported. A 66-year-old man with regrowth of right sphenoid ridge meningioma, whose meningioma had partially been removed 15 years before, was admitted to our clinic. The tumor was large enough to protrude into the lateral and third ventricles, and involved the right internal carotid, middle cerebral, anterior cerebral artery and optic nerve. The tumor had irregular contour, and was heterogeneously enhanced by Gd-DTPA on MRI. An operation was performed, but a part of the tumor around these main arteries could not be removed. Histopathological examination revealed anaplastic meningioma, resulting from malignant change. Radiotherapy was performed postoperatively and the patient was discharged. Seven months after the operation he complained of posterior nuchal, back, and lumbar pain. Radiological examination revealed multiple punched-out lesions in the ribs and vertebrae, which were histologically demonstrated to be metastases of intracranial anaplastic meningioma. Radiotherapy was carried out for the cervical vertebrae, but his symptoms persisted. He died of pneumonia 10 months after the operation.

Aged↗
PubMed1995

[TSH-secreting fibrous pituitary adenoma showing calcification: a case report].

TSH-secreting pituitary adenoma with calcification and proliferation of the collagen fibers was presented. A 42-year-old man had shown general fatigue and thyroid hypertrophy caused by hyperthyroidism for 3 years. CT and MRI revealed pituitary adenoma with calcification extending into the cavernous sinus and sphenoid sinus. The patient was operated on using the transsphenoidal route twice, but the tumor was not able to be removed totally, partly due to the hardness of the tumor. The tumor in- and around the left cavernous sinus as well as the hardest part of the tumor itself due to the calcification could not be removed. Histopathological examination revealed chromophobe adenoma with proliferation of the collagen fibers. Immunohistological and electronmicroscopic examination demonstrated TSH-secreting adenoma. Postoperatively, thyroid function improved and the patient's symptoms due to hyperthyroidism disappeared.

Adenoma, Chromophobe↗
PubMed1994

Tissue density and state of activation of eosinophils in the nasal mucosa of allergic and nonallergic rhinopathic patients.

The tissue density of eosinophils and the degree of activation of eosinophils in the nasal mucosa of allergic and nonallergic rhinopathic patients were studied by a combination of the immunogold method, which uses EG2 antibody which binds to the secreted form of eosinophils, and the Luna method. The tissue density of eosinophils and the degree of EG2-positivity were higher in the allergic nasal mucosa than in the nonallergic nasal mucosa. The eosinophils in the tissue were mainly EG2-positive in contrast with those in the vessels. Epithelial shedding was rarely observed and was not related to the tissue density of eosinophils or EG2-positivity. Our results suggest that the eosinophils in the allergic nasal mucosa are activated in the tissue, not in the vessel.

Adolescent↗
PubMed1994

Rapid and simple method for preparation of genomic DNA from easily obtainable clotted blood.

A method was developed for the preparation of genomic DNA from clotted blood that is usually discarded after extraction, for other laboratory tests. The method, which involves proteinase K digestion, salt/chloroform extraction and 90% ethanol precipitation of DNA from clotted blood, is rapid, simple, and easy because it does not impose an extra burden on the patient.

DNA↗
PubMed1994

Nasal polyp inflammation. Effect of topical nasal steroid.

Topical nasal corticosteroid therapy produces clinical improvement in patients with nasal polyposis. To examine the mechanisms of steroid effect, we quantified the number of inflammatory cell types as well as the expression of relevant cell markers in nasal polyps from steroid treated patients (n = 11) and polyps from untreated patients (n = 10) judged to require polypectomy for symptomatic relief. We found that the majority of eosinophils in these tissues were in the stromal layers, and that the proportion of activated eosinophils (EG2+ versus total eosinophil count) was significantly lower in polyps from patients treated with the topical nasal steroid budesonide, 200 to 400 micrograms/d for 1 mo, than in polyps from untreated patients. We also found that in polyps from treated patients, the superficial stromal layer (SSL) and deep stromal layer (DSL) both contained a significantly lower tissue density of lymphocytes of CD3, CD4, and CD8 subsets. Treatment was also associated with a lower, albeit nonsignificant, expression of ICAM-1 and HLA-DR in the epithelium. The tissue density of CD14+ cells (monocyte/macrophage) and of tryptase+ cells (mast cells) was the same in the two groups. These findings demonstrate tissue effects of topical corticosteroid treatment which may point to the mechanisms of therapeutic benefit. In addition, these observations illustrate the value of markers that indicate cell functional activity rather than just cell numbers.

Administration, Intranasal↗
PubMed1993

Steroid-induced depletion of mucosal mast cells and eosinophils in intestine of athymic nude rats.

In conventional rats, we have previously demonstrated that corticosteroid treatment caused macrophage engulfment and destruction of intestinal mucosal mast cells and eosinophils by 24 h without evidence of local tissue destruction, inflammation or secretion of rat mast cell protease II. As the growth and survival of these cells appear to be dependent on factors derived from T lymphocytes, we examined the response in congenitally athymic rnu/rnu rats and euthymic rnu/+ rats 35 days after parasitic infection. Rats were injected intraperitoneally with 1 mg dexamethasone and sections of jejunum were examined at 0, 7, 13 and 24 h. The numbers of mucosal mast cells significantly decreased in both groups and became less than 30% of the original values at 24 h. Tissue mast cell protease decreased similarly. However, protease in serum did not increase and there were no inflammatory changes at any time. The numbers of eosinophils also rapidly decreased and became less than 20% at 24 h in both rnu/rnu and rnu/+ rats. By electron microscopy, we saw granular changes (fusion) in mast cells and nuclear changes (apoptosis) in eosinophils by 7 h after corticosteroid in athymic rats. Macrophage engulfment of these cells was observed at 7 and 13 h. Our results suggest that inflammatory cell depletion by macrophages is not dependent on suppression of typical thymus-derived T lymphocytes, and may be due either to direct effects of steroids on the cells themselves, or indirectly upon cells other than T cells which normally supply maintenance and growth factors for them.

Animals↗
PubMed1993

[Giant plasmacytoma of the skull which appeared in the clinical course of multiple myeloma--a case report].

A 51-year-old woman with large plasmacytoma occurring from the temporal bone is presented. She has a history of multiple myeloma for 9 years. She manifested marked swelling in the left temporal area with tenderness. Neurological examination revealed no abnormality. She showed monoclonal free light chain (lambda type) in the serum and urine, and had multiple osteolytic lesions in her general bones. T1 WI of MRI exhibited a huge mass showing slightly high intensity in the left middle fossa and infratemporal fossa, and a part of the mass protruded into the extracranial space. The mass was markedly enhanced by Gd-DTPA. Angiography showed a hypervascular mass supplied by the external carotid artery. Biopsy disclosed plasmacytoma. She underwent local irradiation of 30 Gy and chemotherapy of Ranimustine (100 mg) and Cyclophosphamide (400 mg). The tumor reduced its size, and tenderness in her temporal area disappeared.

Cerebral Angiography↗