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Biomedical subjects

K Iwata

Publications and source records attributed to K Iwata.

At least 199 records · Page 11Linked to original sources

Expression of a hybrid complement regulatory protein, membrane cofactor protein decay accelerating factor on Chinese hamster ovary. Comparison of its regulatory effect with those of decay accelerating factor and membrane cofactor protein.

C activation on the cell surface is supposedly regulated by membrane cofactor protein (MCP) and decay accelerating factor (DAF). These are complementary in function: MCP acts as a cofactor in factor I-mediated C3b and C4b inactivation, thus preventing the assembly of C3 convertases, whereas DAF accelerates spontaneous decay of the assembled C3 convertase. In this report, a hybrid MCP-DAF was expressed on Chinese hamster ovary cells by transfecting cDNA, and its regulatory activity was compared with those of MCP and DAF transfectants and with a transfectant expressing both MCP and DAF (MCP + DAF). The C3 deposition on sensitized CHO cells through activation of the classical pathway was blocked to a different degree with these transfectants, the order being MCP + DAF > DAF > hybrid MCP-DAF > MCP. Likewise, the C3 deposition via the alternative pathway was blocked efficiently in the order hybrid > MCP + DAF > MCP. The C-mediated cytolysis of CHO cells virtually reflected the degree of C3 fragment deposition. The MCP-DAF transfectant acquired additive protective activity against alternative pathway-mediated C3 deposition and cytolysis but was less potent in circumventing classical pathway attack than cells that expressed DAF alone or DAF + MCP. Hybrid MCP-DAF may be useful for alleviating C-mediated cell damage, especially via the alternative pathway.

Animals↗

Multisample analysis using an array of microreactors for an alternating-current field-enhanced latex immunoassay.

To develop a rapid and multisample analysis system for latex immunoassay with submicroliters of sample, an array of microreactors were fabricated using micromachining techniques including photolithography, anisotropic etching, and thin gold film deposition. The chamber volume for immunoreactions of a single well was 0.4 microL. An alternating-current (ac) field was used to enhance the rate of the latex agglutination reaction. By applying an ac field for 1 min, alpha-fetoprotein in several samples could be determined simultaneously. The detection limit in this system was approximately 10 pg/mL.

Female↗

Effect of interstimulus interval on perceived sensation and intradental nerve activity during thermal tooth stimulation in man.

The effect of interstimulus interval on nerve responses and subjective sensory ratings evoked by thermal stimulation of the teeth were studied in man. A total of 30 unitary discharges during heat stimulation of the lower incisor teeth were recorded from the inferior alveolar nerves using microneurographic technique. Fifteen of them had threshold sensory ratings above 3 (pain related-units) and 15 had ratings of less than 2 (non-pain-related units). Repetitive heat stimulation was applied to the teeth with interstimulus intervals of 180 s (ISI 180) and 30 s (ISI 30). Repetitive (ISI 180 and ISI 30) non-painful heat stimulation of the teeth did not alter either the intensity ratings or unitary discharge activities of non-pain-related units (P > 0.05). Repetitive painful heat stimulation of the teeth with ISI 180 did not alter the intensity ratings of pain-related units (P > 0.05), whereas that with ISI 30 significantly reduced the intensity ratings of pain-related units during a second session of heat trials (P < 0.05). On the other hand, repetitive heat stimulation of the teeth with ISI 180 caused a slight reduction in the firing frequency of pain-related units (P > 0.05). Repetitive painful heat stimulation with ISI 30 significantly reduced the firing frequency of pain-related units (P < 0.05).

Adult↗

Sulfated proteoglycans in the lamina cribrosa of normal monkey eyes and monkey eyes with laser-induced glaucoma.

The distribution of the sulfated proteoglycans in the lamina cribrosa of normal monkey eyes and monkey eyes with laser-induced glaucoma were analysed by electron microscopy after cuprolinic blue dye binding. Three types of cuprolinic blue-positive filaments, CB-1, CB-2 and CB-3, were identified in the laminar beams of normal monkey eyes. CB-1 and CB-2 were both small filaments representing chondroitin and dermatan sulfate proteoglycan copolymers. The former lined up perpendicularly to the long axis of collagen fibrils, whereas the latter ran axially parallel to collagen fibrils. The large CB-3 filaments, representing chondrotin sulfate proteoglycans, were located around collagen bundles or in loose spaces within the beams. In addition, small CB-4 filaments or punctate structures representing heparan sulfate proteoglycans were found aligned on the basal laminae of blood vessels and glial cells. In the glaucomatous eyes, accumulation and enlargement of collagen-associated proteoglycan filaments were seen, accompanied by the destruction of collagenous beams. Accumulation of chondroitin sulfate proteoglycans was most evident. Prominent filamentous heparan sulfate/heparin proteoglycans were also noted in thickened astrocytic and vascular basal laminae. These may be alterations secondary to the destruction of collagen bundles. They may also represent cellular responses related to intraocular pressure elevation.

Animals↗

Nonanastomotic aneurysm formation in a Dacron arterial graft: report of a case.

Dacron prostheses are the most widely used grafts in replacement procedures for abdominal aortic aneurysms, having been proven as the most reliable substitute for arterial replacement. However, we present herein the rare case of an 82-year-old woman in whom nonanastomotic aneurysm formation occurred in the graft as a complication associated with a Dacron prosthesis. The patient presented with a pulsatile mass in the right inguinal region. She had undergone surgery 13 years earlier for an abdominal aortic aneurysm, at which time an aortobifemoral graft reconstruction had been performed with a double-velour knitted Dacron prosthesis. The pulsatile mass was found to be a nonanastomotic aneurysm of the right limb of the bifurcated graft with an intact distal anastomosis. In this case, the development of the graft aneurysm seemed to result from deterioration of the Dacron prosthesis itself due to mechanical fatigue caused by the inguinal band.

Aged↗

Identification of tissue inhibitor of metalloproteinases-1 (TIMP-1) in human teeth and its distribution in cementum and dentine.

An inhibitory activity toward matrix metalloproteinases such as interstitial collagenase, 72-kDa gelatinase/type IV collagenase, and stromelysin-1 was detected in an EDTA extract of pulverized roots of human teeth, and identified as TIMP-1 by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and immunoblotting. Distribution of TIMP-1 in human cementum and dentine was investigated by a sandwich enzyme immunoassay in combination with an abrasive microsampling technique. TIMP-1 could not be detected in cementum from some teeth but in others decreased from a fairly low value at the surface towards the cementodentinal junction. TIMP-1 concentrations in the dentine increased consistently from the cementodentinal junction toward the predentine. The average TIMP-1 concentration in the dentine (54.1 +/- 18.5 pg/mg +/- SE) was significantly (P < 0.05) higher than that (9.6 +/- 6.0 pg/mg +/- SE) in the cementum.

Adolescent↗

MRI findings in spinal cord injury patients who have respiratory distress.

The present study is an attempt to determine the prognostic capability of magnetic resonance imaging (MRI) in patients with a spinal cord injury (SCI) in the acute phase. The overall management of SCI patients is a prime consideration, and special precautions are required when the patient has respiratory distress. Twelve patients with a complete cervical injury accompanied by respiratory distress were examined by MRI, and a correlation of the MRI findings and the respiratory problems were investigated. In three cases with severe respiratory distress, the SCI was present above the C4-5 level, and MRI showed a high signal intensity at the upper C3. The severity of the respiratory failure was well correlated with the upper margin of the high signal intensity on T2-weighted images.

Adolescent↗

Mortality among inhabitants of an HTLV-I endemic area in Japan.

A community-based cohort study was conducted to clarify the risk of human T-cell leukemia virus type I (HTLV-I) infection for cause-specific deaths. A total of 1,997 individuals (751 men and 1,246 women) aged 30 or older in A-Island, Nagasaki Prefecture, Japan who had voluntarily attended annual mass health examinations, including serum HTLV-I antibody test, were followed up for a mean period of 5.3 years. In a Cox proportional hazards analysis adjusted for age at baseline, the HTLV-I seropositivity was found to be associated with mortality from all causes in men (hazard ratio (HR) 1.89; 95% confidence interval (CI) 1.01-3.54) and women (HR 1.94; 95% CI 1.16-3.22). When the effects of 2 deaths (1 man and 1 woman) from adult T-cell leukemia/lymphoma (ATL) were excluded, the mortality risk decreased slightly but was still significantly or marginally significantly greater than 1 in both men (HR 1.77; 95% CI 0.93-3.37) and women (HR 1.87; 95% CI 1.12-3.12). Further analysis of cause-specific deaths revealed a significant increase in the risk for non-neoplastic diseases but not for neoplasms excluding ATL. These findings suggest that long-term HTLV-I infection represents a health hazard greater than just that for the development of ATL. It was difficult, however, to draw a conclusion regarding the association between HTLV-I infection and cancer risk, because the number of cancer deaths was small and the incidence of cancer was not investigated.

Adult↗

Collagenase activity and tissue inhibitor of metalloproteinases-1 (TIMP-1) content in human whole saliva from clinically healthy and periodontally diseased subjects.

Total TIMP-1 concentration in whole saliva of periodontally diseased subjects, 137 +/- 67 ng/ml (mean +/- SD), was clearly lower (p < 0.001) than that of clinically healthy subjects, 273 +/- 145, and that of edentulous subjects, 332 +/- 121. On the contrary, both active [1.58 +/- 0.35 units/ml (mean +/- SD)] and total (2.08 +/- 0.25) collagenase activities in TIMP-1-free whole saliva of diseased subjects were significantly higher than the activities (0.14 +/- 0.14 and 0.50 +/- 0.27, respectively) in TIMP-1-free whole saliva of healthy subjects. Most of the total collagenase in whole saliva of healthy subjects consisted of procollagenase, while mainly active collagenase was present in whole saliva from patients with periodontal diseases. Significant reciprocal changes of TIMP-1 and collagenase levels, that is, increase in TIMP-1 concentration and decrease in collagenase activity, were observed after the initial therapy of periodontitis patients.

Adolescent↗

[Purpura fulminans complicating pneumococcal sepsis: a case report].

An unusual case of a 67-year-old man is reported with fulminant pneumococcal sepsis. He had been healthy before, and the identified predisposing factors were only that he was a chronic alcohol drinker and was a HCV carrier. He presented signs of acute renal failure, liver dysfunction, adult respiratory distress syndrome and disseminated intravascular coagulation. Subsequently purpura fulminans (symmetrical peripheral gangrene) with major extremity involvement developed. He finally survived with amputation of both legs, right forearm and two fingers of left hand. Purpura fulminans is a rare catastrophic disease, with initial hemorrhagic skin lesions that progress to gangrene. It usually follows an infectious illness, and although it most commonly occurs in children, it can occur in adults with predisposing factors such as alcoholic, asplenia, AIDS and so on. In adults, pneumococcus and meningococcus are microorganisms that have been reported most frequently as caused agents in Europe and America. But in Japan the previously reported adult case was the only one complicating Xanthomonas maltophilia sepsis, and none accompanying pneumococcal sepsis. Congenital protein C deficiency is recognized to be able to cause purpura fulminans especially in patients with risk factors. In our case, protein C antigen was decreased in the acute stage but gradually increased later toward normal, so this decrease was thought to be concomitant with the initial disseminated intravascular coagulation rather than compatible with protein C deficiency.

Aged↗

Morphology of primary somatosensory cortical neurons receiving input from the tooth pulp.

1. To elucidate the morphological and electrophysiological characteristics of tooth pulp-driven neurons (TPNs) in the primary somatosensory cortex (SI), we injected neurobiotin into TPNs whose electrophysiological characteristics had been identified. 2. TPNs, responsive to electrical stimulation of the tooth pulp, were recorded intracellularly and injected from areas 3a and 3b of SI. A total of 58 TPNs in SI were successfully injected and reconstructed. Nineteen of these TPNs were located in area 3a and 39 in area 3b. Three area 3a TPNs were identified in lamina II, eight in lamina III, seven in lamina V, and one in lamina VI. Five 3b TPNs were identified in lamina II, 19 in lamina III, 7 in lamina IV, 7 in lamina V, and 1 in lamina VI. 3. Thalamic and tooth pulp latencies of lamina III and IV TPNs were shorter than those of lamina II and V TPNs. On the other hand, lingual and masseteric nerve latencies of TPNs were not consistent with thalamic and tooth pulp latencies. 4. Three of 19 area 3a TPNs and 7 of 39 area 3b TPNs were classified as pulp-specific TPNs, which received only tooth pulp input. Thirteen of 19 area 3a TPNs and 24 of 32 area 3b TPNs were classified as low-threshold mechanoreceptive TPNs, which responded to nonnoxious mechanical stimulation of the receptive field, and only 2 area 3b TPNs were classified as wide-dynamic range TPNs. Six of the area 3a TPNs and 14 of the area 3b TPNs responded to electrical stimulation of the lingual and/or masseteric nerves. Nociceptive-specific TPNs were not recorded in this study. 5. Lamina II TPNs in areas 3a and 3b had small somata, and those in area 3a had dendrites spreading into laminae I-II. Two TPNs in area 3a had axon collaterals extending into area 4. In contrast, area 3b TPNs in lamina II have dendrites spreading into laminae I-III. Their axons did not extend deeply into the subcortical regions, and the axon collaterals reached into area 3a. 6. Lamina III TPNs were classified according to their morphological characteristics as pyramidal or nonpyramidal stellate TPNs. Pyramidal lamina III TPNs had typical pyramidal somata, like those of lamina V pyramidal cells. Furthermore, those in areas 3a and 3b had dendrites with numerous spines spreading into laminae I-III, and some of the area 3a TPNs have axons with collaterals projecting into area 4. Lamina III area 3b TPNs had morphological properties similar to those in area 3a.(ABSTRACT TRUNCATED AT 400 WORDS)

Afferent Pathways↗

The collagen fibrillar network in the human pial septa.

The three-dimensional organization of the collagen fibrils in the human pial septa was studied by transmission electron microscopy and by scanning electron microscopy after cell maceration with sodium hydroxide. The collagen fibrils along the nerve fibers were loosely distributed thin filaments with a diameter ranging from 25 to 40 nm (mean, 32 +/- 6 nm). Most fibrils were oriented perpendicularly to the long axis of the nerve fiber. In the deeper stroma of the pial septa, collagen fibrils were well packed and the diameter was 40 +/- 6 nm (range, 35 to 50 nm). The scanning electron microscopic study demonstrated a smooth, fabric-like structure formed by wavy and loosely interwoven thin collagen fibrils. Under high magnification, multiple collagenous sheets were observed in the pial septa by scanning electron microscopy. In addition to the structure of loosely arranged thin fibrils on the surface layer adjacent to the nerve fibers, two distinct patterns of collagen fibril network were demonstrated in the deeper stroma. One exhibited fibrils with random distribution, and the other showed well-packed, undirectionally oriented collagen. Small openings corresponding to elastic tissues were also observed. This collagen architecture may contribute to the flexibility and tensile strength of the pial septa required in the intraorbital portion of the optic nerve.

Adult↗

[Deterioration of liver function following endoscopic injection sclerotherapy of esophageal varices--significance of a new index for liver function "delta TB"].

Changes of liver functions associated with endoscopic injection sclerotherapy (EIS) in which less than 6 ml of 5% ethanolamin oleate was used were investigated in 50 patients with remarkable esophageal varices. The index used for evaluating hepatic reserve was the difference of total bilirubin in serum between immediately and 15 hours after EIS and was tentatively named as "delta TB" (normal range < or = 0.1). In the patients classified as Child-Pugh A (n = 25), Child-Pugh B (n = 19) and Child-Pugh C (n = 6), delta TB was 0.04 +/- 0.30, 0.23 +/- 0.41, and 0.54 +/- 0.21, respectively. One month after the entire sessions of EIS, the changes of liver function tests before and after EIS were compared in 45 cases. It was disclosed that delta TB was elevated in parallel with the severity of their liver dysfunction before EIS. Also, delta TB seems to reflect the prognosis of the patients treated by EIS for some extent, since the survival period of the cases treated by EIS were correlative with delta TB (r = -0.734, p < 0.01), and delta TB of 20 cases who survived for longer than 5 years after EIS was 0.04 +/- 0.32. Therefore, delta TB seems to be a useful marker for estimating the influence of EIS on liver function.

Adult↗

[Results of annual health examination for the aged provided by the law that are predictive of increased mortality risk].

Possible risk factors associated with mortality were studied in a community using data derived from annual mass health examinations for the aged mandated by law. A total of 1,804 adults (685 men and 1,119 women) aged 40 or older in A-town, located on Tsushima Island, Nagasaki Prefecture, Japan who had participated in annual health examinations at least once between 1984 and 1990, were followed for a mean period of 4.9 years. After adjustment for age using Cox proportional hazards models, in men liver dysfunction (aspartate aminotransferase > 40 U/l or alanine aminotransferase > 35 U/l), fasting blood glucose > or = 110 mg/dl and glucosuria, and in women serum creatinine > or = 1.2 mg/dl, fasting blood glucose > or = 110 mg/dl and proteinuria were found to be associated with a significantly increased risk of total mortality. In multivariate analysis using all independent variables that were significantly associated with mortality in age-adjusted bivariate analysis, in men liver dysfunction and hyperglycemia, and in women hypercreatininemia and hyperglycemia, were significant predictors of mortality. These independent variables remained significant or marginally significant predictors of total mortality even after excluding the effects of 3 pancreatic cancer cases with liver dysfunction or hyperglycemia or 12 deaths within the first year of follow-up, being associated with at least two-fold increased hazard rate ratios. From these results, it is recommended that persons with these risk factors be followed intensively and counseled by public health personnel to modify risk factors.

Adult↗

[Intraoperative fluorescein angiography with an ultrasensitive imaging tube].

Fluorescein angiographic examination may be prevented by vitreous hemorrhage or opacities in vitreoretinal diseases before vitrectomy. We performed intraoperative fluorescein angiography for such cases, using a conventional light source and an ultrasensitive video camera equipped with a silicone intensifier target tube to avoid retinal phototoxicity. Intraoperative fluorescein angiograms allowed evaluation of neovascular vessels, proliferative tissues, and avascular areas associated with diabetic retinopathy. Indentation of the pars plicata enabled us to also record fluorescein images of the area. This device may aid intraoperative assessment of vitreoretinal diseases including diabetic retinopathy.

Fluorescein Angiography↗