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Kenji Nishida

Publications and source records attributed to Kenji Nishida.

8 recordsLinked to original sources
PubMed2006

Single-molecule analysis of epidermal growth factor binding on the surface of living cells.

Global cellular responses induced by epidermal growth factor (EGF) receptor (EGFR) occur immediately with a less than 1% occupancy among tens of thousands of EGFR molecules on single cell surface. Activation of EGFR requires the formation of a signaling dimer of EGFR bound with a single ligand to each molecule. How sufficient numbers of signaling dimers are formed at such low occupancy rate is still not known. Here, we have analyzed the kinetics of EGF binding and the formation of the signaling dimer using single-molecule imaging and mathematical modeling. A small number of EGFR on the cell surface formed dimeric binding sites, which bound EGF two orders of magnitude faster than the monomeric binding sites. There was a positive cooperative binding of EGF to the dimeric binding sites through a newly discovered kinetic intermediate. These two mechanisms facilitate the formation of signaling dimers of EGF/EGFR complexes.

Binding Sites↗
PubMed2005

Noninsulinoma pancreatogenous hypoglycemia syndrome: a rare case of adult-onset nesidioblastosis.

The most common cause of hyperinsulinemic hypoglycemia in adults is insulinoma. Nesidioblastosis is a rare, but well-recognized disorder of persistent hyperinsulinemic hypoglycemia in infancy, but adult-onset nesidioblastosis associated with hyperinsulinemic hypoglycemia, termed noninsulinoma pancreatogenous hypoglycemic syndrome (NIPHS), has been reported. Here, we describe an extremely rare case of NIPHS in an elderly man. A 78-year-old man was admitted to our hospital due to hypoglycemic coma. During the previous 3 months, he noticed excessive sweating at midafternoon. His low fasting plasma glucose level (27 mg/dl) and high immunoreactive insulin level (11.1 muU/ml) were consistent with the possible presence of insulinoma. Localizing studies including computed tomography of the abdomen and celiac arteriography were negative, but selective arterial calcium infusion (SACI) test suggested the presence of insulinoma in the body and tail of the pancreas. Surgical exploration by palpation and intraoperative ultrasonography failed to detect any mass in the pancreas, and 60% distal pancreatectomy was performed. Postoperatively, his hypoglycemic episodes completely disappeared. Histological examination of the resected pancreas revealed diffuse islet cell hyperplasia consistent with a pathological diagnosis of nesidioblastosis. Thus, our case is a very rare case of NIPHS, or adult-onset nesidioblastosis, in which SACI test was proven to be a useful diagnostic tool for localization of the pancreatic lesion.

Age of Onset↗
PubMed2004

High molecular weight form insulin-like growth factor II-producing mesenteric sarcoma causing hypoglycemia.

An 81-year-old woman presented with frequent episodes of hypoglycemia. Her serum level of insulin was normal, but her serum insulin-like growth factor (IGF)-II level was high. She was found to have a spindle cell sarcoma originated from the mesentery of the sigmoid colon, which was completely resected. Postoperatively, hypoglycemia ameliorated with concomitant reduction in serum IGF-II levels. Immunohistochemical study revealed positive immunostaining for IGF-II in tumor cells, and the abundant expression of IGF-II mRNA was demonstrated by RT-PCR. The presence of high molecular weight (HMW) form IGF-II in patient's serum was confirmed by immunoblotting. This is the first report of a patient with HMW form IGF-II-producing mesenteric sarcoma causing hypoglycemia.

Aged↗
PubMed2003

Grazing exit electron probe microanalysis of submicrometer inclusions in metallic materials.

Grazing exit electron probe microanalysis (GE-EPMA) is a new method of EPMA in which characteristic X-rays emitted from only near-surface regions of a specimen are detected at extremely low exit angles near 0 degrees (the grazing exit condition). This technique requires the analytical objects exist on a flat surface. Therefore, the GE-EPMA analysis has been used only for the analysis of particles or a thin film on a flat substrate so that there were only few applications for practical analysis. As a new application, we have carried out GE-EPMA analysis of approximately 0.2-microm inclusions on stainless steel, which appeared to be a projection on the specimen surface with chemical etching. The GE-EPMA quantitative results were in excellent agreement with those of inclusions that were extracted from the stainless steel and analyzed by EPMA with conventional exit condition (30 degrees). This method could be, therefore, applied to the analysis of the submicrometer inclusion in a wide variety of metallic materials if the inclusion appears to be a projection with chemical etching treatment.

Journal Article↗
PubMed2003

Development of a new method for measuring total urinary protein using acid violet 6B pigment.

We have developed a new method for measuring total urinary protein using acid violet 6B (AV6B) pigment. Nine purified components of human urinary proteins and urine samples collected randomly from 123 diabetic outpatients were used. There were 62, 36, and 25 cases of prenephropathy, early nephropathy, and overt nephropathy, respectively. All samples were measured by Coomassie brilliant blue G 250 (CBB), pyrogallol red-molybdate (PRM), and AV6B methods using an optical photometer. In healthy subjects, the major components of urinary proteins, such as gamma-globulins, IgG, IgA Tamm-Horsfall protein, and transferrin, the reactivity values of the AV6B and PRM methods were similar. The CBB method was the least sensitive of the three methods. In the urine samples from diabetic patients, the urinary protein values measured by the AV6B method were higher than those measured by the CBB method in the prenephropathy stage. The values obtained by the AV6B method (y) correlated well with those from the CBB method (x) (y=1.243x+3.61, r=0.904). When the values from the AV6B method (y) were compared to those from the PRM method (x), correlation was low (y=1.406x-29.15, r=0.786). In conclusion, the AV6B method was more useful than the CBB and PRM methods for low levels of urinary protein.

Adult↗
PubMed2003

Life history of Manataria maculata (Lepidoptera: Satyrinae) from Costa Rica.

The life history and early stages of the satyrine butterfly Manataria maculata are described and illustrated from Costa Rica. Eggs are laid on Lasiacis sp. (Panicoideae), a new non-bamboo host plant for the genus Manataria. The larval stage varied from 23 to 28 days, and the pupal duration was approximately 12 days when reared on Bambusa vulgaris and Guadua angustifolia in captivity at 23-24 degrees C.

Animals↗
PubMed2002

A new species of Pediobius (Hymenoptera: Eulophidae) from Epilachna (Coleoptera: Coccinellidae) in Costa Rica.

A new and morphologically very distinct species of Pediobius from Costa Rica is described. The new species (P. nishidai) is unique among New World species of Pediobius in having the propodeum elongated and extended backwards (i.e. with an elongated nucha). The entire type series (15 females, two males) was reared from a single prepupa of Epilachna mexicana and it has been concluded that the new Pediobius species is a gregarious endoparasitoid that pupates inside its host. The possible use of this new species as a biological control agent against "the Mexican bean beetle" (E. varivestis) should be tested.

Animals↗