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Biomedical subjects

M Furukawa

Publications and source records attributed to M Furukawa.

At least 199 records · Page 11Linked to original sources
PubMed1996

Distribution of Ca2+ channels on cochlear outer hair cells revealed by fluorescent dihydropyridines.

Physiological evidence has shown that cochlear outer hair cells (OHC) possess L-type voltage-dependent Ca2+ channels through which Ca2+ enters the OHC during depolarization. Their subcellular distribution has, however, remained unclear. In this study, the distribution of L-type Ca2+ channels on the basolateral plasma membrane of OHC has been demonstrated by the use of a laser scanning confocal microscope (LSCM) and a fluorescent probe DMBODIPY-DHP. The fluorescent staining pattern on the basolateral wall is nonuniform, suggesting a heterogeneous distribution of the channels in the plasma membrane. Direct imaging of intracellular Ca2+ visualized in real time by means of the LSCM and the fluorescent Ca2+ probe fluo 3 revealed temporal and spatial integration of Ca2+ movements and Ca2+ channel distribution. Exposure to high-K+ solution induced heterogeneity in the subcellular increase in the intracellular Ca2+ concentration. These results suggest that the heterogeneous distribution of L-type Ca2+ channels on the basolateral membrane might induce heterogeneous intracellular Ca2+ distribution during electrical activity in the OHC.

Animals↗
PubMed1996

Culture and characterization of human nasal gland cells.

To study the regulation of ion transport by human nasal gland (HNG) cells, we developed a system for culturing HNG cells isolated by enzymatic digestion from human nasal polyps. When plated on flasks in media containing. Ultroser G serum substitute and a variety of growth factors, the HNG cells became confluent after 5-7 days. Cells were collected by trypsinization and replated at 10(6) cells/cm2 on porous filters. Confluent monolayers formed on days 3-5 after replating and were studied on days 5-7. Transepithelial resistance and short-circuit current (Isc) were 177 +/- 15 omega.cm2 and 12.2 +/- 1.3 microA/cm2 (means +/- SE, n = 35). Acetylcholine (ACh, 10(-5) M) induced a transient increase in Isc by 4.4 +/- 1.0 microA/cm2 when added to both apical and basolateral sides and returned to baseline levels within 5 min. Diphenylamine-2-carboxylate (10(-3) M) decreased baseline Isc by 30.2 +/- 1.7% (n = 6) and inhibited Isc responses induced by ACh. Amiloride also decreased baseline Isc by 12.3 +/- 3.4% (n = 6) but failed to inhibit ACh-induced Isc responses. ACh (10(-5) M) also induced an increase in intracellular Ca2+ concentration measured by fura 2-AM from 60.5 +/- 16.3 to 248.3 +/- 45.3 nM (n = 4). These findings suggest that gland cells from human nasal polyps can be grown in culture to produce epithelial cell sheets of high resistance, which secrete Cl- in response to cholinergic agent via an increase in intracellular Ca2+ concentration.

Adolescent↗
PubMed1996

Squamous cell carcinoma of the scrotum.

A patient with psoriasis was found to have a large skin tumor on his scrotum. He had received psoralen and ultraviolet A radiation therapy to control psoriasis. Histopathologic study revealed that the tumor was a well-differentiated squamous cell carcinoma. We present this rare case and suggest that the genitalia be shielded during ultraviolet therapy.

Aged↗
PubMed1996

Clinical evaluation of extracorporeal shock wave lithotripsy for salivary stones.

The treatment of sialolithiasis is discussed in this report. Generally, stones within the distal salivary duct are easily removed by transoral ductotomy, although proximal stones are usually treated by excision of the salivary gland and its duct. Since 1980, extracorporeal shock wave lithotripsy (ESWL) has been in clinical use for the treatment of renal and gallbladder stones. We used this technique as a treatment for sialolithiasis. We undertook ESWL on 14 submandibular gland stone patients and 1 parotid gland stone patient, clinical symptoms such as pain and swelling disappeared without excision of the affected salivary gland. Stones larger than 10 mm seem to have a tendency to form Steinstrassen. Although computed tomography findings correlate with success in breaking up gallstones, they did not predict success for salivary stones. We conclude that sialolithiasis is treated successfully without adverse effects by ESWL in selected patients.

Adolescent↗
PubMed1996

[Cochlear implant in a child with acquired deafness].

The auditory training course of a 3-year-5-month-old child with acquired deafness who received a Nucleus 22 channel implant is reported. Soon after switching it on, her response was not very clear. There was good subsequent progress in auditory discrimination, whereas the patient's major communication strategy preoperatively had been manual, lip-reading, and written language. Her vowel discrimination score reached 100% in 8 months. The patient's articulation and speech intonation has also improved, and her auditory reception of environmental sounds has also shown relative improvement.

Child, Preschool↗
PubMed1996

[Neuroendocrine carcinomas of the head and neck].

Neuroendocrine carcinomas (NECs) of the head and neck are rare. Between 1980 and 1995, only 163 cases of laryngeal and 30 cases of sinonasal NEC had been reported worldwide. We report two cases of sinonasal NEC. Case 1: A 49-year-old man complaining of left nasal obstruction was admitted to our hospital. A tumor with a tendency to bleed was seen in the left nasal cavity. CT scanning revealed an enhanced mass in the left nasal cavity and both maxillary and ethmoid sinuses. An open biopsy was performed to determine the diagnosis. The diagnosis of NEC was based on light microscopic and immunohistochemical findings. Chemotherapy and radiation were performed, but bone, liver and brain metastasis occurred 15 months after diagnosis and the patient died. Case 2: A 59-year-old man, complaining of right forehead swelling visited our department. CT scanning and MRI revealed that the right ethmoid sinus was filled by a tumor which had invaded the base of the skull. An open biopsy was performed. From the results of light microscopic and immunohistochemical investigations, NEC was highly suspected. Chemotherapy and radiation were performed, but the patient died 6 months after diagnosis. This study shows that there are aggressive types of nasal NEC, although these sinonasal carcinomas were reported in the literature to be not very lethal. The diagnosis, histopathological classification, treatment, and prognosis of sinonasal and laryngeal NECs were reviewed.

Carcinoma, Neuroendocrine↗
PubMed1996

[Clinical review of 105 cases of adrenal tumor, with special reference to incidental tumor].

We reviewed 105 patients with adrenal tumor diagnosed at our institute from January 1984 to December 1993. In 74 patients tumors were symptomatically diagnosed (the symptomatic group), while in the remaining 31 patients tumors were incidentally detected (the incidental group). In 5 cases of the incidental group, tumors were found at a routine health examination, whereas in the remaining 26 cases tumors were found during the examination or treatment for unrelated diseases. On both the incidental group and symptomatic group, higher right-to-left side ratio was noted in the laterality of tumors detected by ultrasound scanning. The size of tumors in the incidental group was significantly larger than that in the symptomatic group, but there was no significant difference in size between the tumors detected by ultrasound and those detected by CT scan in either the symptomatic group or in the incidental group. In the symptomatic group 71 patients (95.9%) were found to have functioning tumor, where the most common diagnosis was primary aldosteronism (44 cases), and 68 of the 71 patients received adrenalectomy. While in the incidental group 12 patients (38.7%) were found to have functioning tumor, where the most common diagnosis was pheochromocytoma (7 cases), followed by Cushing's syndrome (3 cases) including one case with so-called pre-Cushing's syndrome, and all of the 12 patients received adrenalectomy. Of 16 primary incidental adrenal tumors which did not have any hormonal functions, 5 tumors larger than 30 mm in diameter were resected and the remaining 11 tumors were followed up without operation. Since the incidence of incidental adrenal tumor may increase in the future, careful diagnosis and decision of indication for surgery are required.

Adolescent↗
PubMed1996

Elevated interleukin-8 levels in the urine of children with renal scarring and/or vesicoureteral reflux.

PURPOSE: Elevation of urinary levels of interleukin-6 and 8 has been observed in patients with acute urinary tract infections. However, to our knowledge there have been no studies concerning the secretion of interleukin-6 and 8 into the urine after acute inflammation has resolved and renal scarring has occurred. On the other hand, it is well known that cytokines are variously related to glomerular diseases and, thus, it is possible that the progression of reflux nephropathy depends on interleukin-6 or 8. Therefore, we assessed urinary levels of interleukin-6 and 8 in children with vesicoureteral reflux and/or renal scarring. MATERIALS AND METHODS: We evaluated interleukin-6 and interleukin-8 levels in the urine of 32 children without a urinary tract infection who presented or were admitted to our hospital because of vesicoureteral reflux between April and December 1994. Interleukin-6 and 8 were determined using a commercially available human enzyme-linked immunosorbent assay kit and the 2-step sandwich method. RESULTS: Urinary interleukin-6 levels were below the lower detection limit (less than 10 pg./ml.) in all samples. There were statistically significant differences between urinary interleukin-8 levels in children with and without renal scarring (p = 0.001), and with and without vesicoureteral reflux (p = 0.0246). CONCLUSIONS: Urinary interleukin-8 is an effective marker for renal scarring and vesicoureteral reflux.

Adolescent↗
PubMed1996

[Interaction between Epstein-Barr virus (EBV) gene expression and antibodies to EBV in nasopharyngeal carcinomas].

In situ hybridization using EBERs and BHLF oligonucleotide probes and immunohistochemistry using monoclonal antibodies against LMP1, EBNA2, BZLF1 protein, p53 protein and bcl-2 protein were performed on 56 primary nasopharyngeal carcinomas. EBERs was detected in 46 cases (82%), and LMP in 17 cases (30%), but EBNA2 was not detected. While 30 of 32 cases (94%) in differentiated non-keratinizing carcinoma (NKC) and 16 of 17 cases (94%) in undifferentiated carcinoma (UNPC) showed EBERs, neither 5 cases of squamous cell carcinoma (SCC) nor 2 cases of adenocarcinoma showed EBERs. This finding confirms latent infection of EBV, especially phenotypical latency II, in NKC and UNPC but not in SCC. Bcl-2 protein was positive in 50 cases (89%), but its expression did not depend on expression of LMP1, which did not demonstrate induction of bcl-2 by LMP1 as seen in vitro. Cytoplasmic BZLF1 expression was detected in 18 cases (32%) whereas BHLF was positive only in 6 cases (11%). This suggests dysfunction of BZLF1, which disrupts viral latency despite its expression. p53 protein was positive in 31 cases (55%), and there was a distinct correlation between expression of BZLF1 and p53 protein (p < 0.001). This suggests that the interaction between BZLF1 protein and p53 protein, which inactivate each other, is one of the tumorigenic factors in NPC.

Adolescent↗
PubMed1996

HLA-DR8 subtyping by polymerase chain reaction (PCR)-DNA conformation polymorphism (DCP) analysis: a simple and practical genotyping method.

Two hundred Japanese panels were serologically typed for human leukocyte antigen (HLA) - DR to assign 65 HLA-DR8 haplotypes, which were then subdivided into two genotypes, i.e., DRB1*0802 and DRB1*0803, by a polymerase chain reaction (PCR)--based, simple, and practical method. The panels possessing DR8 specificity were firstly subjected to PCR with a couple of primers specifically to amplify their DR52 associated group--DRB1 genes. PCR products were then denatured in the presence of formamide, electrophoresed in a non-denaturing polyacrylamide gel, and visualized by silver staining. The same DRB1 products of these samples were also mixed with the DRB1*1302, and simultaneously analyzed by the same procedure. Electrophoretic mobilities of the samples were compared with those of the typing standards to genotype their DR8--DRB1 alleles by using the characteristic polymorphism in the single-stranded DNAs and the heteroduplexes. This method, designated PCR--DNA conformation polymorphism (DCP) analysis, allowed for genotyping of the DR8-DRB1 alleles without using sequence-specific oligonucleotide probes (SSOP) or restriction endonucleases. The entire process after PCR was completed within a few hours. The tested panels were also genotyped for DRB1 gene by the PCR-SSOP method for comparison with results obtained by the PCR-DCP method. Satisfactory coincidence was achieved and it represented how accurately the new system genotyped DRB1*0802 and DRB1*0803. PCR-DCP analysis was thus shown to be practical and useful for subtyping of serologically defined DR8 specificities.

Base Sequence↗
PubMed1996

Detection of cytokine expression in human palatine tonsils.

We investigated cytokine mRNA expression in human palatine tonsils from 20 patients. Expression of TNF-alpha mRNA was detected in 11 of 20 patients. IL- 1 alpha mRNA was detected in 2 patients and IL-2 mRNA in one patient. No expression of IL-4, IL-6 and interferon-gamma was detected in any of the 20 patients. TNF-alpha may play an important role in tonsillar diseases.

Cytokines↗
PubMed1995

Cloning, characterization, and tissue distribution of porcine SPAI, a protein with a transglutaminase substrate domain and the WAP motif.

The primary and gene structures and tissue distribution of porcine SPAI-2, a protein that belongs to the WAP protein superfamily and has a sodium-potassium ATPase inhibitory activity, were determined by molecular cloning and Northern analysis. A full-length cDNA clone was isolated from a porcine duodenum cDNA library. The cDNA insert encoded a polypeptide of 187 amino acids, which is composed of three domains: a hydrophobic presequence of 21 amino acids, a prosegment of 105 amino acids ending with Asp126, and the mature SPAI-2 sequence of 61 amino acids beginning with Pro127. The prosegment contained 16 repeats of a hexapeptide that is highly homologous to the repetitive sequence found in the transglutaminase domain of the human elafin, an elastase-specific inhibitor that also belongs to the WAP superfamily. The repetitive sequence was demonstrated to be a good substrate of transglutaminase using a recombinant preparation produced in Escherichia coli. A porcine genomic library was then screened for the SPAI gene. Characterization and sequencing of positive clones indicated that the gene is similar to the elafin gene, having 3 exons encoding the 5'-untranslated region and signal sequence, proSPAI, and 3'-untranslated region, respectively. Northern blot analysis revealed intestine-specific expression of SPAI mRNA; the message was especially abundant in the small intestine. ProSPAI was also found in the circulation. The similarity of proSPAI to elafin in the domain structure, the acid-labile nature of the cleavage site (Asp126-Pro127), and the fact that the major form of SPAI in the plasma is proSPAI strongly suggest that proSPAI is not the precursor but rather it is the native form of SPAI. Like elafin, therefore, SPAI appears to be a new type of biologically active substance with a transglutaminase substrate domain that acts as an anchoring sequence.

Amino Acid Sequence↗
PubMed1995

Initiation of insulin secretion in glucose-free medium by activin A.

Activin A is a multifunctional protein known to stimulate insulin secretion (Yasuda H et al., (1993) Endocrinology 133, 624-630). The present study was conducted to determine whether activin A augments insulin secretion in the absence of ambient glucose. In the presence of 2.7 mM glucose, and 1.25 mM calcium, activin A induced a biphasic secretory response of insulin. In the absence of glucose in perifusate, activin A induced a small but significant release of insulin. The effect of activin A was monophasic in the absence of glucose. In contrast, glucagon-like peptide-1 (GLP-1) had no effect on insulin secretion under the same conditions. However, GLP-1 could enhance insulin secretion induced by activin A in glucose-free medium. Activin A induced a transient increase in cytoplasmic-free calcium concentration, [Ca2+]c, in a fura-2-loaded islet superfused with glucose-free buffer. Again, GLP-1 was without effect on [Ca2+]c by itself in glucose-free buffer. In the presence of activin A, however, GLP-1 could induce an elevation of [Ca2+]c. Finally, GLP-1, but not activin A, increased cAMP content in islets incubated in glucose-free medium. These results indicate that activin A, but not GLP-1, induces insulin secretion in glucose-free medium. Activin A is able to reproduce partly the effect of glucose to support the action of GLP-1 in glucose-free medium.

Activins↗