Biomedical subjects

A Ishida

Publications and source records attributed to A Ishida.

At least 55 records · Page 3Linked to original sources

PubMed2001

[Immunohistochemical study of KL-6 in pulmonary tuberculosis].

KL-6 is a glycoprotein antigen derived from the cell line of human lung adenocarcinoma. Although KL-6 is known to be a serum marker of interstitial pneumonia, elevated KL-6 serum levels have also been reported in some cases of pulmonary tuberculosis. To elucidate the mechanism of KL-6 elevation in pulmonary tuberculosis, we stained pulmonary tissue samples from five clinical cases for immunohistochemical analyses. In the two cases showing productive changes, KL-6 immunoreactivity was localized in the area of type II pneumocytes showing strong interstitial changes surrounding caseous necrosis. In the two cases showing exudative changes, KL-6 immunoreaction was observed not only to surround caseous necrosis but also to appear within it, particularly in the remaining alveolar lumen septa. On the other hand, the one patient with old pulmonary tuberculosis that showed slight interstitial changes presented with weak KL-6 immunoreactivity on the surface of the alveolar lumen surrounding the tuberculotic region. These results suggest that serum elevation of KL-6 in pulmonary tuberculosis originates from the proliferation of type II pneumocytes along with interstitial changes that surround the tuberculous region.

Antigens↗

PubMed2001

[Behavior of drinking alcoholic beverages among junior and senior high school students in the area covered with Wakkanai Health Center of Hokkaido, Japan].

We conducted a survey on behavior of drinking alcoholic beverages among students in November, 2000 in the area covered with Wakkanai Health Center of Hokkaido, Japan. A questionnaire was completed by 743 junior high school students (88.9% of the study subjects) and 791 senior high school students (76.3% of the study subjects). As a result, the proportion of the students who drank more than once per month was higher in this area than in other places of Japan. For example, 90.2% and 87.9% in the male and female senior high school students of the third grade drank more than once per month. Their frequent drinking was not related to their early onset of drinking. They often drank alone or only with their friends. Frequent drinkers among the students tended to get alcohol beverages from various roots, including face-to-face salespersons in package stores, convenience stores, or bars. Frequent drinkers among the students tended to have more experienced the problems associated with drinking such as blackout and vomiting. A large proportion of the students in this area had relatively poor knowledge about harmfulness of drinking. It has been suggested that people in this area are permissive to drinking among youngsters, as compared to other places in Japan. We think that it is indispensable to communicate or educate harmfulness of drinking during adolescence for students as well as for their parents, especially, in this area.

Adolescent↗

PubMed2000

Apoptosis has a prolonged role in the neurodegeneration after hypoxic ischemia in the newborn rat.

Birth asphyxia can cause moderate to severe brain injury. It is unclear to what degree apoptotic or necrotic mechanisms of cell death account for damage after neonatal hypoxia-ischemia (HI). In a 7-d-old rat HI model, we determined the contributions of apoptosis and necrosis to neuronal injury in adjacent Nissl-stained, hematoxylin and eosin-stained, and terminal deoxynucleotidyl transferase-mediated UTP nick end-labeled sections. We found an apoptotic-necrotic continuum in the morphology of injured neurons in all regions examined. Eosinophilic necrotic neurons, typical in adult models, were rarely observed in neonatal HI. Electron microscopic analysis showed "classic" apoptotic and necrotic neurons and "hybrid" cells with intermediate characteristics. The time course of apoptotic injury varied regionally. In CA3, dentate gyrus, medial habenula, and laterodorsal thalamus, the density of apoptotic cells was highest at 24-72 hr after HI and then declined. In contrast, densities remained elevated from 12 hr to 7 d after HI in most cortical areas and in the basal ganglia. Temporal and regional patterns of neuronal death were compared with expression of caspase-3, a cysteine protease involved in the execution phase of apoptosis. Immunocytochemical and Western blot analyses showed increased caspase-3 expression in damaged hemispheres 24 hr to 7 d after HI. A p17 peptide fragment, which results from the proteolytic activation of the caspase-3 precursor, was detected in hippocampus, thalamus, and striatum but not in cerebral cortex. The continued expression of activated caspase-3 and the persistence of cells with an apoptotic morphology for days after HI suggests a prolonged role for apoptosis in neonatal hypoxic ischemic brain injury.

Animals↗

PubMed2000

Induction of the urokinase plasminogen activator system by oncostatin M promotes endothelial migration.

Oncostatin M (OSM) is an inflammatory cytokine produced by activated macrophages and T-lymphocytes. We have previously demonstrated that OSM-induced endothelial cell migration, unlike endothelial cell proliferation and spindle formation, is independent of basic fibroblast growth factor expression (Wijelath et al. [1997] J. Cell. Sci. 110:871-879). To better understand the mechanism of OSM-induced endothelial cell migration, this study examined the potential role of the plasminogen activator system in promoting OSM mediated endothelial cell migration. OSM stimulated increased mRNA levels of urokinase-plasminogen activator (uPA) and urokinase-plasminogen activator receptor (uPAR) in a time and dose-dependent manner. Transcriptional run-off and mRNA stability analysis demonstrated that the increase in uPA and uPAR mRNA levels was due to both increased gene transcription and mRNA stability. The increase in mRNA correlated with increased protein levels of both uPA and uPAR. This increase was reflected in elevated levels of membrane-bound plasmin activity. OSM-induced endothelial cell migration was only partially dependent on plasmin activity since incubating endothelial cells without plasminogen or, in the presence of aprotinin, resulted in suppression of endothelial cell migration, indicating that OSM promoted endothelial cell migration through both a plasmin-dependent and -independent mechanism. Our results imply a role for OSM in promoting endothelial cell migration via a plasmin-dependent pathway and a uPAR-mediated pathway. Together, these and other recent studies support a role for OSM in modulating the different phases of angiogenesis.

Cells, Cultured↗

PubMed2000

Linkage between alpha(1) adrenergic receptor and the Jak/STAT signaling pathway in vascular smooth muscle cells.

The Jak/STAT pathway is activated following stimulation of the type I angiotensin II receptor. To examine whether this pathway is shared among other G-protein-coupled receptors, we studied the linkage between the alpha(1) adrenergic receptor and this pathway. The alpha(1) agonist phenylephrine induced tyrosine phosphorylation of Jak2, Tyk2, and STAT1 in vascular smooth muscle cells. The phosphorylation of Jak2 was prevented by the alpha(1) receptor antagonists prazosin and chloroethylclonidine, but not by WB4101, and that of STAT1 was inhibited by prazosin and the Jak2 inhibitor AG490. After stimulation with phenylephrine, Jak2 and STAT1 were found to associate with alpha(1B) receptor. Phenylephrine stimulated the DNA binding activity of STAT1. Protein synthesis promoted by phenylephrine was inhibited by prazosin, AG490, and the introduction of a decoy oligonucleotide for STAT1. These results suggested that alpha(1) receptor is linked to the Jak/STAT pathway and that this pathway mediates alpha(1) agonist-induced smooth muscle hypertrophy.

Adrenergic alpha-Agonists↗

PubMed2000

Enhanced endothelialization and microvessel formation in polyester grafts seeded with CD34(+) bone marrow cells.

The authors have shown accelerated endothelialization on polyethylene terephthalate (PET) grafts preclotted with autologous bone marrow. Bone marrow cells have a subset of early progenitor cells that express the CD34 antigen on their surfaces. A recent in vitro study has shown that CD34(+) cells can differentiate into endothelial cells. The current study was designed to determine whether CD34(+) progenitor cells would enhance vascular graft healing in a canine model. The authors used composite grafts implanted in the dog's descending thoracic aorta (DTA) for 4 weeks. The 8-mm x 12-cm composite grafts had a 4-cm PET graft in the center and 4-cm standard ePTFE grafts at each end. The entire composite was coated with silicone rubber to make it impervious; thus, the PET segment was shielded from perigraft and pannus ingrowth. There were 5 study grafts and 5 control grafts. On the day before surgery, 120 mL bone marrow was aspirated, and CD34(+) cells were enriched using an immunomagnetic bead technique, yielding an average of 11.4 +/- 5. 3 x 10(6). During surgery, these cells were mixed with venous blood and seeded onto the PET segment of composite study grafts; the control grafts were treated with venous blood only. Hematoxylin and eosin, immunocytochemical, and AgNO(3 )staining demonstrated significant increases of surface endothelialization on the seeded grafts (92% +/- 3.4% vs 26.6% +/- 7.6%; P =.0001) with markedly increased microvessels in the neointima, graft wall, and external area compared with controls. In dogs, CD34(+) cell seeding enhances vascular graft endothelialization; this suggests practical therapeutic applications. (Blood. 2000;95:581-585)

Animals↗

PubMed2000

Dynamic Changes of Smooth Muscle and Endothelial Markers in the Early Healing Process of Dacron Vascular Grafts in the Dog, Using RT-PCR.

Previous studies of neointima formation on Dacron vascular grafts mainly focused on the late stages using immunohistochemistry staining for von Willebrand factor (vWF) and smooth muscle (SM) alpha-actin. However, it is impossible to use immunohistochemistry to study the early events of neointima formation, because graft samples lack sufficient cellular material. Therefore, we used reverse transcriptase-polymerase chain reaction (RT-PCR) to demonstrate dynamic changes of SM and endothelial markers during the early stages of neointima formation. Preclotted Dacron grafts were implanted in the descending thoracic aorta of 14 mongrel dogs. Specimens were retrieved at 1-4 weeks. Total RNAs were extracted from mid-portion of graft flow surfaces, and RT-PCR for vWF, SM myosin heavy chain (MHC), and SM alpha-actin were performed and expressed as a ratio to the ribosome s17 signal. SM MHC and vWF mRNA expression was low at 1-2 weeks but elevated at 3-4 weeks (P < 0.05). However, SM alpha-actin mRNA levels were expressed consistently throughout the study period. At 3-4 weeks, vWF mRNA expression was inversely correlated to thrombus formation on the graft flow surface. Increased expressions of SM MHC and vWF mRNA corresponded to the formation of neointima and an endothelial layer at the later stages. However, SM alpha-actin mRNA expression did not vary during the healing process. The application of RT-PCR should permit further studies of gene regulation in the early vascular graft healing process in vivo. This model can also be used to study the molecular events that are involved in SM cell differentiation.

Journal Article↗

PubMed2000

Up-regulation of galectin-3 in acute renal failure of the rat.

Galectin-3, a multifunctional beta-galactoside-binding lectin, is known to participate in development, oncogenesis, cell-to-cell attachment, and inflammation. We studied to determine whether galectin-3 is associated with cell injury and regeneration in two types of acute renal failure (ARF), namely ischemic and toxic ARF. In ischemia/reperfusion renal injury in rats (bilateral renal pedicles clamped for 40 minutes), galectin-3 mRNA began to increase at 2 hours and extended by 6.2-fold at 48 hours (P: < 0.01 versus normal control rats), and then decreased by 28 days after injury. In addition, a significant negative correlation between galectin-3 mRNA expression and serum reciprocal creatinine was shown at 48 hours after injury (n = 13, r = -0.94, P: < 0.0001). In folic acid-induced ARF, galectin-3 mRNA was found to be up-regulated at 2 hours after injury and increased levels continued until at least 7 days post-injury. In immunohistochemistry, at 2 hours following reperfusion, galectin-3 began to develop in proximal convoluted tubules. From 6 hours up to 48 hours, galectin-3 was also found in proximal straight tubules, distal tubules, thick ascending limbs, and collecting ducts. In later stages of regeneration, galectin-3 expressions were found in macrophages. In conclusion, we demonstrated that galectin-3 expressions were markedly up-regulated in both ischemic and toxic types of ARF. Galectin-3 may play an important role in acute tubular injury and the following regeneration stage.

Acute Kidney Injury↗

PubMed2000

Approach to ex vivo gene therapy in the treatment of Parkinson's disease.

Approaches to ex vivo gene therapy hold great promise for the treatment of central nervous system disorders where there is currently no care or enough treatment for suffering patients. In this review we have focused on the application of ex vivo gene therapy techniques in Parkinson's disease models, however, the issues and approaches are applicable to other neurodegenerative disorders. In utilizing the ex vivo strategy two considerations are critical for delivery of therapeutic levels of transgene product to the target organ: (i) the vector system and (ii) the cell type for grafting. We describe different vector systems that are currently available and review the various cell types that have been genetically modified and grafting into the striatum of animal models with experimental Parkinson's disease. The strategies for application of gene therapy techniques to the treatment for Parkinson's disease have expanded beyond the classical dopamine replacement toward the use of neurotrophic factors in enhancing cell function or preventing cell death. In addition, we explore the utility of autologus primary skin fibroblasts as alternative cell type for ex vivo gene therapy in the animal model of Parkinson's disease. These results have general implications for the application of ex vivo gene therapy to human neurological diseases and specific implications for Parkinson's disease.

Animals↗

PubMed2000

Effect of antagonistic voluntary contraction on motor responses in the forearm.

OBJECTIVE: We investigated the effects of voluntary contraction of agonist and antagonist muscles on motor evoked potentials (MEP) and on myoelectric activities in the target (agonist) muscle following transcranial magnetic stimulation (TMS). METHODS: The left extensor carpi radialis (ECR) and flexor carpi radialis (FCR) muscles were studied in 16 healthy subjects. H reflexes, MEP induced by TMS, and background electromyographic (EMG) activity were recorded using surface electrodes at rest and during voluntary contraction of either agonist or antagonist muscles. RESULTS: Voluntary contraction of antagonist muscles (at 10% of maximum contraction) enhanced the amplitudes of MEP for both muscles. The H reflex of the FCR muscle was inhibited by contraction (10% of maximum) of the ECR muscle. Background EMG activity did not differ between H-reflex trials and TMS trials. Enhancement of MEP amplitudes and background EMG activity during voluntary antagonist contraction was comparable in the two muscles. Appearance rate of MEP recorded by needle electrodes in response to subthreshold TMS was increased by antagonistic voluntary contraction. CONCLUSION: Facilitation occurs during voluntary contraction of antagonist muscles. Differences between the effects of voluntary contraction of the ECR muscle for the MEP and the H reflex of the FCR suggest that cortical facilitatory spread occurs between agonist and antagonist muscles.

Adult↗

PubMed2000

Diagnostic sensitivity of predicted F-wave latency by age, height, and MCV.

OBJECTIVES: The aim was to investigate whether minimum F-wave latency (Fmin) predicted by a multiple regression equation utilizing age, height, and motor nerve conduction velocity (MCV) (3-factor method) was clinically useful to detect Fmin abnormality in diabetic polyneuropathy (DP) and lumbosacral monoradiculopathy (RAD). MATERIALS AND METHODS: Thirty-one DP patients (ulnar, tibial, and peroneal nerves) and 66 RAD patients (peroneal nerve) were investigated. The specificity and sensitivity of the 3-factor method were compared to those obtained by a univariate (height) regression method (1-factor method) and another multivariate (height and age) regression method (2-factor method). RESULTS: In general satisfactory specificity was obtained with all three methods. In DP patients the tibial 3-factor method showed statistically lower sensitivity than the other two methods. There were no significant differences in diagnostic sensitivity among the three methods in two other nerves of the DP patients and the peroneal nerve of the RAD patients. CONCLUSION: The 3-factor method was useful to estimate Fmin in normal subjects, but it was of little value in increasing the diagnostic sensitivity in DP and RAD patients. The 2-factor method was more appropriate for detecting DP.

Adolescent↗

PubMed2000

Risk-adapted pre-emptive therapy for cytomegalovirus disease in patients undergoing allogeneic bone marrow transplantation.

We prospectively evaluated a risk-adapted pre-emptive treatment with ganciclovir for CMV diseases in patients undergoing allogeneic bone marrow transplantation (BMT). High-level CMV antigenemia (10 or more positive cells on two slides) or CMV antigenemia at any level in patients with grade II-IV acute graft-versus-host disease (aGVHD) were chosen as risk factors. We also retrospectively evaluated virus reactivation in plasma using quantitative real-time polymerase chain reaction (PCR). Fifty patients were evaluable. None of the 27 patients with or without grade I aGVHD developed high-level CMV antigenemia or CMV disease. Among the 23 patients with grade II-IV aGVHD, 12 patients (52%) developed CMV antigenemia and were treated pre-emptively, of whom two developed CMV gastroenteritis or retinitis in spite of therapy. Six of the remaining 11 patients developed CMV gastroenteritis before CMV antigenemia was detectable. All of the eight patients with CMV diseases were successfully treated with ganciclovir and no deaths directly related to CMV disease occurred. In four of the seven evaluable patients with CMV gastroenteritis, real-time PCR was able to detect virus reactivation earlier than CMV antigenemia. Although our risk-adapted pre-emptive therapy effectively reduced CMV-related mortality, further refinements of this approach, particularly in the prevention of CMV gastroenteritis, may be achieved by incorporating real-time PCR.

Adolescent↗

PubMed2000

Changes in patterns of left ventricular hypertrophy after aortic valve replacement for aortic stenosis and regurgitation with St. Jude Medical cardiac valves.

In this study, we analyzed the extent and pattern of regression of left ventricular (LV) hypertrophy after aortic valve replacement in patients with aortic stenosis (AS) and compared the results with those of another group of patients with aortic regurgitation (AR). Seventy patients who underwent isolated aortic valve replacement were divided into 2 groups. Group 1 was comprised of 29 patients who underwent aortic valve replacement for aortic stenosis, and Group 2 of 41 patients who underwent aortic valve replacement for aortic regurgitation. A third group of 10 healthy subjects served as a healthy control group. Echocardiographic studies were done before the operation and 5 years postoperatively. At follow-up, a significant reduction in the left ventricular mass was found in both groups, but it remained significantly greater than in the healthy control group. The ratio of LV wall thickness to radius (th/r) in Group 1 decreased significantly, and at follow-up it was within the normal value. In Group 2, the th/r ratio increased, and at follow-up it was within the normal value. After aortic valve replacement, the wall thickness remained significantly greater than normal for patients with AS, and the chamber radius remained significantly greater than normal for patients with AR. For these reasons, LV hypertrophy still existed in both groups at postoperative follow-up. The actuarial survival rate was 85.3% at 16 years for Group 1 and 83.4% at 18 years for Group 2. There was no significant difference in the long-term survival rates between the 2 groups. Actuarial freedom from valve-related events was 91.9% at 16 years for Group 1 and 82% at 18 years for Group 2. There was no significant difference in the valve-related event free curves between groups. After 5 years of follow-up, th/r reached normal for both groups, indicating remodeling of the LV geometry after aortic valve replacement.

Adult↗

PubMed2000

Novel treatments after experimental brain injury.

Perinatal hypoxic-ischaemic encephalopathy(HIE) is being studied in laboratory models that allow the delayed cascade of events triggered by the energetic insult to be examined in detail. The concept of the 'excitotoxic cascade' provides a conceptual framework for thinking about the pathogenesis of HIE. Major events in the cascade triggered by hypoxia-ischaemia include overstimulation of N-methyl-D-aspartate type glutamate receptors, calcium entry into cells, activation of calcium-sensitive enzymes such as nitric oxide synthase, production of oxygen free radicals, injury to mitochondria, leading in turn to necrosis or apoptosis. New experimental approaches to salvaging brain tissue from the effects of HIE include inhibition of neuronal nitric oxide synthase, administration of neuronal growth factors, and inhibition of the caspase enzymes that execute apoptosis. Recent experimental work suggests that these approaches may be effective during a longer 'therapeutic window' after the insult, because they are acting on events that are relatively delayed. Application of modest hypothermia may allow these agents to be neuroprotective at even longer intervals after hypoxia-ischaemia.

Animals↗

PubMed2000

[Experiences with the alloplastic joint prosthesis of the interphalangeal joint].

The replacement of finger joints, especially of the proximal interphalangeal joint (PIP), remains an unsolved problem. Long-term results of conventional reconstructive procedures as well as previously available artificial joint implants have been disappointing. In a controlled study, 12 PIP-joints were replaced by a new type of total endoprosthesis as an alternative to joint fusion. The cementless prosthesis is unhinged and consists of metal joint surfaces. After a follow-up of 18 months, implantation of this metal prosthesis resulted in almost complete pain relief and an active range of movement of 58 degrees. The absolute gain in mobility, however, was only 6 degrees. A swan-neck deformity was found in nine out of 12 cases but corrective surgery was not required. The proximal half of the implant had to be exchanged in two cases due to loosening. All patients were satisfied with the result. The disparity between subjective acceptance by the patients, who clearly prefer joint replacement to fusion, and objective results demonstrates the necessity for further development in this field. The type of prosthesis used in this study seems to be a useful baseline tool which could be turned into a ingenious PIP-joint replacement by further development aiming at reduced abrasion, increased initial stability, a more individual configuration, to name just a few goals.

Equipment Failure Analysis↗

PubMed2000

Microvascular anastomoses using an Nd-YAG laser.

The authors performed anastomoses of small vessels with the Nd-YAG laser, comparing these with conventional suture anastomoses. Some arteries were sutured with 10-0 nylon with about eight suture sites, and others were held by stay sutures at three points with laser irradiation performed between them. Two surgeons performed the anastomoses in the same way. The first was well-trained and experienced, and the second was technically inexperienced. The authors evaluated clamping time, patency rate, and endoscopic and histologic findings. The patency rate of the first surgeon was 100 percent (30/30) in the suture anastomoses and was 97 percent (29/30) in the laser anastomoses. For the second surgeon, the rates were 60 percent (18/30) in the suture group and 80 percent (24/30) in the laser group. On histologic examination, the suture group showed inflammatory cells around the suture site at the fourth week after the operation. In the laser group, an inflammatory reaction around the suture material was observed, but the other areas recovered. For the experienced surgeon, the patency rate and clamping time of the laser anastomosis provided no statistically significant difference to those of the suture anastomosis. On the other hand, for the inexperienced surgeon, the patency rate of the laser anastomosis was superior to that of the suture anastomosis, and the clamping time of the laser anastomosis was shorter than that of the suture anastomosis. Therefore, the authors concluded that the Nd-YAG laser anastomosis is useful for small vessels.

Anastomosis, Surgical↗

PubMed2000

Administration of granulocyte colony-stimulating factor enhances endothelialization and microvessel formation in small-caliber synthetic vascular grafts.

OBJECTIVE: The purpose of this study was to determine whether systemic administration of granulocyte colony-stimulating factor (G-CSF) would promote endothelialization for small-caliber Dacron vascular grafts. METHODS: We implanted 4-mm preclotted Dacron grafts in both carotids of 12 dogs. For a fair comparison, all dogs had a comparable platelet aggregation profile with platelet aggregation scores less than 30. Five dogs served as controls, and the others were given 7-day subcutaneous injections of G-CSF (10 microg/kg per day), starting on the seventh postoperative day. The effect of G-CSF was evaluated by white blood cell count, which showed a 3.7-fold (+/- 2.7-fold) increase at the end of treatment. Grafts were harvested at 4 weeks. All G-CSF grafts were patent, and one control occluded. Endothelial-like cell coverage averaged 80.8% on G-CSF grafts, but only 35.6% for control grafts (P <.0004). With the exclusion of the anastomotic pannus healing factor, the difference in endothelial-like cell coverage was even greater (68.5% vs 9.8%; P <.0001). Immunocytochemical staining and electron microscopy studies demonstrated endothelial cells. Light microscopy also showed that there were more microvessels on and in the G-CSF grafts than in the control grafts. This study suggests that G-CSF can enhance early endothelialization of small-caliber vascular grafts. Further studies to determine the proper dosage and timing are needed before clinical application can be recommended.

Animals↗

PubMed2000

Acclimation of leaf characteristics of Fagus species to previous-year and current-year solar irradiances.

To examine the effects of different solar irradiances on leaf characteristics at the leaf primordium and expansion stages, we shaded parts of branches in the upper canopies of two adult beech trees, Fagus crenata Blume and Fagus japonica Maxim., for 4 years. The treatments during the leaf primordium and leaf expansion stages, respectively, were: (1) high light and high light (H, control), (2) high light and low light (HL), (3) low light and low light (LL), and (4) low light and high light (LH). Both number of cell layers in palisade tissue and individual leaf area were affected by the previous-year irradiance, whereas cell length of palisade tissue was larger in LH leaves than in LL leaves, suggesting determination by current-year irradiance. Lamina chlorophyll/nitrogen ratio was higher in HL and LL leaves than in LH leaves, suggesting determination by current-year irradiance. Diurnal minimum values of leaf water potential measured under sunlit conditions were lower in H and LH leaves than in HL and LL leaves. Effective osmotic adjustment was found in H and LH leaves, suggesting that leaf water relations were affected by current-year irradiance. Net photosynthetic rate and stomatal conductance measured under sunlight conditions were higher in H and LH leaves than in HL and LL leaves. Thus, effects of current-year irradiance had a greater effect on leaf-area-based daily carbon gain than previous-year irradiance.

Acclimatization↗