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Biomedical subjects

T Iijima

Publications and source records attributed to T Iijima.

At least 181 records · Page 10Linked to original sources
PubMed1998

High oxygen delivery and extraction by perfluorocarbon-primed extracorporeal membrane oxygenation do not prevent anaerobic metabolism in rabbits.

PURPOSE: This study was designed to evaluate the advantage of perfluorocarbon (PFC) emulsion priming for venoarterial extracorporeal membrane oxygenation (ECMO) by comparison with hydroxyethyl starch (HES) solution in rabbits (2.8 to 3.9 kg). RESULTS: ECMO initiation was accompanied by a profound decrease in hematocrit (from 40.1% to 14.9%) in both groups. The arterial and the right atrial oxygen contents in the PFC group (n = 4; 38.5 and 11.5 mL/dL) were greater than in the HES group (n = 5; 7.0 and 5.1 mL/dL). Right atrial oxygen tension in the PFC group increased at the beginning of ECMO (from 38.4 to 51.2 mm Hg; P = .031) and remained higher than in the HES group for 60 minutes. These results indicate that oxygen supply and extraction in the PFC group were much greater than in the HES group. However, plasma lactate increased progressively during the 120-minute ECMO procedure in both groups (from 1.8 to 14.5 in the HES group, and from 2.3 to 12.2 in the PFC group). CONCLUSION: Perfluorocarbon priming for ECMO, although providing high oxygen delivery and extraction, does not prevent anaerobic metabolism.

Anaerobiosis↗
PubMed1998

Relationships between glutamate release, blood flow and spreading depression: real-time monitoring using an electroenzymatic dialysis electrode.

Spreading depression (SD) in a flow-restricted area of the brain may be prolonged and may become potentially harmful by releasing glutamate. We induced SD in an oligemia model and examined the subsequent glutamate release. In 18 anesthetized male Fischer rats, a laser Doppler flowmeter, an electroenzymatic electrode for continuous measurement of glutamate, and a calomel electrode for measuring DC potential were placed through a cranial window positioned 3 mm away from a second window where KCl-soaked cotton was placed to initiate SD. The left carotid artery or both the common carotid arteries were ligated to suppress reactive hyperemia of SD. SD produced an increase in glutamate from 24.8 +/- 13.8 to 33.5 +/- 25.3 microM (peak value) (P < 0.0001). After ligation of both carotid arteries, the duration of SD increased from 1.5 +/- 0.6 min (before ligation) to 6.4 +/- 5.1 min (P < 0.05). Glutamate reached a peak level of 63.9 +/- 72.3 microM, then quickly returned to the control value. However, there was no positive correlation between the duration of SD and glutamate concentration. It is concluded that prolonged SD is not accompanied by a progressive increase in glutamate. Therefore, glutamate release induced by SD may not exert harmful effects on neurons.

Animals↗
PubMed1998

Macroscopic osseous changes in the temporomandibular joint related to dental attrition in Japanese macaque skull.

The purpose of this study was to investigate the relationship between osseous changes in the temporomandibular joint (TMJ) and dental attrition in the Japanese macaque. One hundred and thirty Japanese macaque skulls (54 male and 76 female) from animals which had been bred in the same environment, were randomly sampled from a collection at the Primate Research Institute of Kyoto University. The age at death had been recorded in all cases. TMJ osseous changes were independently evaluated by three examiners, and were defined as an irregular surface or a perforated compact bone layer with a markedly irregular surface on either the temporal or condylar components. Age was a significant factor in predicting TMJ osseous changes (P < 0.001). A strong relation was observed between age and dental attrition (P < 0.001), while dental attrition was not a significant factor in predicting TMJ osseous changes (P = 0.334). The prevalence TMJ osseous changes in male animals was slightly higher than in females (P = 0.057). The results of this study suggest that osseous changes in the macaque TMJ are mainly related to age, not to dental attrition.

Age Factors↗
PubMed1998

Spreading depression induces depletion of MAP2 in area CA3 of the hippocampus in a rat unilateral carotid artery occlusion model.

Traumatic brain injury (TBI) induces neuronal cell loss in area CA3 of the hippocampus. However, it has not yet been established why traumatic injury of the cortex induces neuronal damage in more remote areas. Spreading depression (SD) may be one potential mechanism for this pathophysiology. The present study evaluated whether SD on the cortex evokes a pathological change in the hippocampus. Forty-two Fisher rats were assigned to four groups: Group I: sham operation (n = 7), Group II: right carotid occlusion (UO) for 7 days (n = 7), Group III: repeated induction of SD by KCl application on dura for 7 days (n = 7), Group III' for 3 h (n = 7), Group IV: SD induction and UO for 7 days (n = 14) Group IV' for 3 h (n = 7). In 5 out of 7 animals in Groups III' and IV', cerebral blood flow (CBF) was monitored using laser Doppler flowmetry for 3 h during the passage of SD. The brains were processed for immunohistochemical analysis of microtubule-associated protein 2 (MAP2). Reactive hyperemia induced by SD was not significantly suppressed by right carotid occlusion (194 +/- 25% and 181 +/- 42% UO in Groups III and IV, respectively). In 6 out of 7 animals in a 7-day model of Group IV, and 3 animals in a 7-day model of Group III, MAP2 depletion in the CA3 area of the hippocampus (partly including CA2) was observed, although no change in the hippocampus was observed in other groups. In conclusion, SD in combination with UO yielded reproducible lesions in CA3. Neuronal injury in the hippocampus after brain trauma may be attributable to SD in combination with the blood flow restriction.

Animals↗
PubMed1998

Circulating blood volume measured by pulse dye-densitometry: comparison with (131)I-HSA analysis.

BACKGROUND: Pulse dye-densitometry (PDD) is a newly developed technique for monitoring the arterial concentration of indocyanine green. Using this method, circulating blood volume (CBV) can be calculated without using radioisotopes. In this study, the CBV value obtained by PDD was validated by comparison using the human serum albumin ((131)I-HSA) dilution method. METHODS: Eleven healthy volunteers underwent placement of cannulae into the radial artery and antecubital vein for withdrawal of blood samples and injection of indicator. Probes for PDD were attached to the right nostril and the right index finger. Indocyanine green (20 mg), dissolved in 4 ml water, and 25 microCi (131)I-HSA in 1 ml distilled water were injected simultaneously into the left antecubital vein. Blood samples were withdrawn 3, 6, 10, 20, 30, and 45 min after injection, then processed for spectrophotometric measurement of indocyanine green and scintillation counting. RESULTS: The blood dye concentration correlated well with the values obtained by PDD (r=0.986, imprecision 0.04+/-0.11 mg/l, 10.0+/-31%. The imprecision of the CBV value obtained by PDD (nose probe) and by the (131)I-HSA dilution method was 3.99+/-10.54%, 0.259+/-0.593 l. The imprecision of the CBV obtained by in vitro spectrophotometry compared with PDD was 2.47+/-9.00%, 0.100+/-0.446 l. CONCLUSIONS: This newly developed, less invasive method can measure CBV with an imprecision of 3.99+/-10.54%, 0.259+/-0.593 l (nose probe), and thus is also as accurate as the conventional radioisotope method.

Adult↗
PubMed1998

The implication of anthracosis in the development of pulmonary adenocarcinoma.

The relationship between anthracosis, which is the deposition of black dust matter in the lung parenchyma, and the development of pulmonary adenocarcinoma has not been fully characterized. In order to clarify whether background black dust matter deposition could be implicated in the development of pulmonary adenocarcinoma, we measured the level of anthracosis at autopsy in 47 patients who had died of pulmonary adenocarcinoma. Both lungs of all 47 cadavers were examined. Twenty-micrometer sections were cut from formalin-fixed, paraffin-embedded blocks of the largest cut surface of each lung. Black dust matter was extracted from the sections and blotted onto a nitrocellulose membrane. The density of the blotted black dust matter was then analyzed using an imaging densitometer. There were no significant differences in the density of black dust matter deposition between lungs affected by pulmonary adenocarcinoma and control lungs. However, well differentiated adenocarcinomas tended to develop more frequently than poorly differentiated ones in lungs showing less deposition. We found a very strong correlation between the degree of black dust matter deposition and smoking history. Patients with severe anthracosis tended to have a poorer prognosis than those with mild anthracosis.

Adenocarcinoma↗
PubMed1998

Interferon-gamma-producing cells and inducible nitric oxide synthase-producing cells in periapical granulomas.

Periapical granulomas contain a large number of T lymphocytes and monocytes/macrophages and a small number of B lymphocytes and polymorphonuclear leukocytes. Sections from eight periapical granulomas were stained by a variety of immunohistochemical methods. The vascular endothelial cells stained positively for intercellular adhesion molecule-1 and vascular cell adhesion molecule-1. Helper T cells were identified by immunostaining for CD4 and stained positively for interferon-gamma (IFN-gamma). However, CD4-positive T cells did not stain for interleukin-4 (IL-4). Monocytes/macrophages were identified by immunostaining for CD68 and stained positively for IL-1alpha or inducible nitric oxide synthase (iNOS). IL-1beta could not be detected in the same samples. No cytokine expression was observed in B cells identified by immunostaining for CD20. IFN-gamma- and iNOS-positive cells could not be detected in clinically healthy periodontal ligament being used as a negative control. These results suggest that the IFN-gamma-producing T cells and iNOS-positive cells may modulate the progress of disease in local inflammation sites such as in periapical granulomas.

Adult↗
PubMed1998

Prediction of postpartum onset of rheumatoid arthritis.

OBJECTIVE: To investigate the prediction of the postpartum onset of rheumatoid arthritis (RA). METHODS: Two thousand five hundred and forty seven healthy pregnant subjects were examined prospectively and the relation between serum rheumatoid factors (RF) and postpartum onset of RA was observed. Rheumatoid factors were measured in early pregnancy by the antihuman IgG latex agglutination test (Latex test) and antirabbit IgG haemagglutination test (RAHA test). RESULTS: Latex test and RAHA test were positive in 26 (1.0%) and 64 (2.5%) pregnant subjects, respectively. Four hundred and ten subjects of 2547 pregnant women could be followed up for one year after delivery. None of 401 subjects without RF, or with only one RF on either Latex test or RAHA test, developed RA after delivery. Two (22.2%) of nine subjects with both RFs developed RA at one and three months postpartum, respectively. Transient arthralgia was found within 12 months postpartum in three of nine (33.3%) subjects with both RFs and this prevalence was significantly higher than that in RF negative subjects (8.1%). CONCLUSION: Postpartum onset of RA was found in at least 2 of 2547 healthy subjects (0.08%) and onset was predicted by positive test for rheumatoid factors.

Adult↗
PubMed1998

Involvement of lymphocyte function-associated antigen-1 and intercellular adhesion molecule-1 in osteoclastogenesis: a possible role in direct interaction between osteoclast precursors.

In our search for molecules involved in the process of osteoclast differentiation, we examined the surface phenotypes of the preosteoclast-like cells and osteoclast-like multinucleated cells (MNCs) formed in bone marrow cultures, using monoclonal antibodies recognizing different antigen molecules expressed on hematopoietic cells. Among these cell surface antigens, lymphocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) were highly expressed on mononuclear cells in the cultures for forming preosteoclast-like mononuclear cells. The double detection of these two antigen molecules with osteoclast-specific antigen and with calcitonin receptor, using a fluorescence-activated cell sorter or autoradiography technique, revealed that LFA-1 and ICAM-1 were expressed on the preosteoclasts. The expression of ICAM-1 was detected on both preosteoclasts and osteoclast-like MNCs, whereas the expression of LFA-1 was restricted to preosteoclasts. We designed a peptide with the sequence of the binding site of ICAM-1 against the ligand LFA-1. In the whole bone marrow culture system for forming osteoclast-like MNCs, a significant inhibition of MNC formation was observed by the addition of this peptide. These results strongly suggest the involvement of an LFA-1/ICAM-1-interaction in osteoclastogenesis.

Animals↗
PubMed1998

Induction of abundant osteoclast-like multinucleated giant cells in adjuvant arthritic rats with accompanying disordered high bone turnover.

The development of an in vivo system for investigating osteoclast differentiation is important because molecular events occurring in vivo can be observed during the differentiation of the authentic osteoclasts. In adjuvant arthritic rats, an experimental model of human rheumatoid arthritis, extensive bone resorption is observed in the distal diaphysis of the tibia. In the area of extensive bone resorption, it is always accompanied with clusters of numerous multinucleated giant cells (MGCs) as well as bone-resorbing osteoclasts. Here we characterized the morphological properties of these MGCs with the use of enzymehistochemical and immunohistochemical techniques. Extensive destruction but also a marked formation of the inner and outer bone surfaces were the predominant features in the tibiae of such arthritic rats 4 weeks after the adjuvant injection. Numerous MGCs were frequently clustered in the bone marrow spaces located apart from the bone matrices. Although the MGCs lacked ruffled borders, these cells were rich in mitochondria and vacuoles. These multinucleated cells revealed a positive reaction for tartrate-resistant acid phosphatase but a negative reaction for non-specific esterase staining. Most of these MGCs expressed the Kat 1-antigen, an immunological marker specifically expressed on the cell surface of rat osteoclasts. In a dentin resorption experiment using a cluster of MGCs excised from the bone marrow tissues of the tibial distal diaphyses of rats with adjuvant arthritis, many resorption lacunae were formed on dentin slices after a 3-day culture. These results suggest that the majority of the MGCs are osteoclasts but not macrophage polykaryons.

Animals↗
PubMed1998

Coronary artery-pulmonary artery fistula originating from three major coronary branches associated with exertional chest pain and tachycardia-dependent left bundle branch block.

A 49-year-old male was admitted to our hospital because of chest pain. The pain occurred simultaneously with tachycardia-dependent left bundle branch block (LBBB) during exercise-stress and atropine-stress electrocardiogram (ECG) and on 24-h ambulatory ECG monitoring. Myocardial perfusion and metabolic scintigraphy with Tl-201 and I-123 BMIPP, respectively, showed no evidence of ischemia. Coronary arteriography revealed no atherosclerotic lesions, but did show a fistula between three major coronary arteries and the main pulmonary artery. The left-to-right shunt was undetectably small. Administration of diltiazem and metoprolol suppressed LBBB by attenuating the heart rate response to exercise, and reduced the chest pain. Therefore we presume that the exertional chest pain was not caused by myocardial ischemia but by the tachycardia-dependent LBBB. Coronary artery-pulmonary artery fistula is the most common type of coronary artery fistulae found incidentally in adulthood. Involvement of three major coronary branches is, however, rare. The case is discussed with a review of the literature.

Bundle-Branch Block↗
PubMed1998

Prolonged hepatic warm ischemia in non-heart-beating donors: protective effects of FK506 and a platelet activating factor antagonist in porcine liver transplantation.

BACKGROUND: Prolonged warm ischemic injury in non-heart-beating donors (NHBDs) significantly affects hepatic allograft function after liver transplantation (LTx). METHODS: The effects of FK506 and the platelet activating factor antagonist E5880 on postoperative function of hepatic allografts procured from NHBDs were evaluated in porcine orthotopic LTx. In donors, livers were subjected to 90 minutes of warm ischemia and a subsequent 4-hour cold preservation. Group 1 (n = 6) was the untreated control group. In group 2 (n = 4), donors were pretreated with FK506 (0.3 mg/kg). In group 3 (n = 4), donors and recipients were treated with E5880 (0.3 mg/kg). In group 4 (n = 6), pigs were treated with both FK506 and E5880. RESULTS: All of the recipients in group 1 died within 12 hours. In groups 2 and 3, half of the recipients survived more than 12 hours. In group 4, all of the recipients survived more than 2 days (p < 0.01 compared with group 1). The improved survival seen in group 4 was associated with a reduction in the serum concentrations of glutamic oxaloacetic transaminase and lactate, and a restoration of hepatic energy charge. CONCLUSIONS: The present study suggests that FK506 and E5880 can improve the function of hepatic allografts subjected to prolonged warm ischemia in NHBDs, and that the protective effects of the two drugs seem to be synergistic.

Adenosine Triphosphate↗
PubMed1998

[The pathophysiology of ischemic neuronal injury: an overview].

Despite the enormous scientific efforts that have been made to clarify the pathophysiology of ischemic neuronal injury, the mechanism responsible for neuronal cell death after ischemia remains unclear. Neuronal injury can be roughly classified into three categories: acute ischemic injury, delayed neuronal death and neuronal injury in the penumbra. Flow disturbance known as the noreflow phenomenon and postischemic hypoperfusion is the first limiting factor for neuronal resuscitation after an ischemic insult. Extracorporeal circulation has been tried in an attempt to prevent this blood flow disturbance, but it has become apparent that this is no more effective than conventional resuscitation. Delayed neuronal death seems to be triggered by short exposure to ischemia. Although a molecular mechanism including "glutamate excitotoxicity" has been proposed to explain this phenomenon, the details are still uncertain. The interventional point underlying the protective effect of hypothermia against delayed neuronal death may be the key to understanding its pathophysiology. Neuronal death in the penumbra seems to show deterioration through a mechanism of repeated depolarization "spreading depression", although spreading depression itself has no harmful effect on neurons. The pathophysiological mechanism of spreading depression in combination with flow restriction and other relevant factors related to ischemia remains to be investigated.

Animals↗
PubMed1997

Overexpression of resistance-related proteins (metallothioneins, glutathione-S-transferase pi, heat shock protein 27, and lung resistance-related protein) in osteosarcoma. Relationship with poor prognosis.

BACKGROUND: The prognosis for patients with osteosarcoma has improved over the past 20 years, mainly due to developments in chemotherapy. Some proteins have been reported to show drug resistance. Theoretically, overexpression of some of these proteins makes treatment difficult, leading to poorer outcome. METHODS: Specimens taken from conventional osteosarcomas of the extremity bones from 60 patients younger than 30 years were used. In all cases, preoperative oncostatic chemotherapy was undertaken after biopsy. If available, biopsy specimens were also used for sequential comparison. Among resistance-related proteins, expression of metallothioneins (MTs), glutathione-S-transferase pi (GST pi), heat shock protein 27 (Hsp27), and lung resistance-related protein (LRP) was evaluated immunohistochemically in paraffin sections. The log rank test was used for univariate analysis and the Cox regression model for multivariate analysis. RESULTS: At biopsy, only overexpression of Hsp27 was associated with poor prognosis. At surgery, a relationship was observed between poor prognosis and overexpression of GST pi, Hsp27, and LRP. Groups overexpressing one protein tended to overexpress another. Overexpression of these proteins in surgical specimens also correlated with histologic response to preoperative chemotherapy and clinical stage. In multivariate analysis, Hsp27 overexpression at biopsy was an independent prognostic factor. CONCLUSIONS: Inherent overexpression of Hsp27 is independently related to poor outcome in osteosarcoma patients. Overexpression of GST pi, Hsp27, and LRP at surgery might be associated with failure of preoperative chemotherapy. Control of the expression of these proteins may improve the outcome for patients with osteosarcoma.

Adolescent↗
PubMed1997

Hepatic allograft procurement from non-heart-beating donors: limits of warm ischemia in porcine liver transplantation.

To investigate the tolerance to warm ischemia of liver grafts from non-heart-beating donors, porcine orthotopic liver transplantation was performed using grafts obtained at various periods after cardiac arrest. Graft viability was investigated in relation to changes in hepatic adenine nucleotide metabolism. In donors, livers were divided into four groups according to warm ischemic time after cardiac arrest (group 1: 0 min, n=3; group 2: 30 min, n=3; group 3: 60 min, n=5; group 4: 90 min, n=4). Thereafter, the livers were flushed and preserved for 4 hr using 4 degrees C Euro-Collins solution. After surgery, all of the recipients in groups 1, 2, and 3 survived more than 4 days, except for one pig in group 3 that died of bleeding from an arterial catheter on day 2. By contrast, all of the recipients in group 4 died within 12 hr. The serum glutamic oxaloacetic transaminase concentration at 4 hr after reperfusion of the graft was significantly higher in group 4 (mean+/-SE, 2563+/-556 IU/L) than in groups 1, 2, and 3 (298+/-29 IU/L, 1226+/-222 IU/L, and 1181+/-174 IU/L, respectively). The adenylate energy charge of the liver graft recovered at 1 hr after reperfusion of the graft to 0.852+/-0.013, 0.845+/-0.003, and 0.842+/-0.003 in groups 1, 2, and 3, respectively. The recovery was significantly suppressed in group 4 (0.796+/-0.011). The hepatic adenosine triphosphate concentration also was significantly lower in group 4 compared with the other groups. The present study suggests that liver allografts can be used from non-heart-beating donors subjected to warm ischemia for less than 60 min. Postoperative survival is associated with prompt recovery of the adenylate energy charge of the liver graft.

Adenine Nucleotides↗
PubMed1997

Differential alteration of hippocampal synaptic strength induced by pituitary adenylate cyclase activating polypeptide-38 (PACAP-38).

We investigated the effect of pituitary adenylate cyclase activating polypeptide-38 (PACAP-38) on synaptic transmission in rat hippocampal slices using extracellular recordings. Brief bath application of PACAP-38 induced a long-lasting depression of transmission at the Schaffer collateral-CA1 synapse while at the same time causing enhancement of the perforant path-granule cell synapse in the dentate gyrus. Depression at the CA1 synapse was not occluded by low frequency-induced long-term depression (LTD), nor was enhancement at the granule cell synapse blocked by previous high frequency-induced long-term potentiation (LTP). Both actions of PACAP-38 could be elicited in the presence of an N-methyl-D-aspartate (NMDA) receptor antagonist, or in the presence of inhibitors of cyclic AMP- or Ca2+-dependent protein kinases, suggesting a novel mechanism of synaptic modulation.

Animals↗