Biomedical subjects

T Kondo

Publications and source records attributed to T Kondo.

At least 541 records · Page 30Linked to original sources

PubMed1997

Early detection of successful coronary reperfusion based on serum concentration of human heart-type cytoplasmic fatty acid-binding protein.

Both human heart-type cytoplasmic fatty acid-binding protein (H-FABPc) and myoglobin are low molecular weight proteins that are abundant in the cytoplasm of myocardial cells. Unlike myoglobin, H-FABPc content in the skeletal muscle is less than in cardiac muscle. To investigate the usefulness of the serum concentration of H-FABPc in the early detection of successful coronary reperfusion, we measured serum concentrations of H-FABPc and myoglobin in 45 patients with acute myocardial infarction treated with intracoronary thrombolysis or direct percutaneous transluminal coronary angioplasty. Coronary angiography was performed every 5 min for reperfusion therapy to identify the onset of reperfusion. Reperfusion, defined as a TIMI grade 2 or 3, was achieved within 60 min of the initiation of reperfusion therapy in 30 patients (the reperfused group), but was not achieved in 15 patients (the non-reperfused group). Blood samples were obtained before initiation of treatment and 15, 30 and 60 min after initiation of treatment in the non-reperfused group. In the reperfused group, samples were obtained before reperfusion and 15, 30 and 60 min after reperfusion. The H-FABPc ratio (the ratio of value after to value before the initiation of treatment or reperfusion) increased sharply after the onset of reperfusion, peaking at 41 +/- 18 min, and decreased rapidly thereafter. The predictive accuracy of an H-FABPc ratio of > 1.8 for the detection of reperfusion within 60 min of the initiation of treatment was 93% at 15 min after reperfusion, 98% at 30 min, and 100% at 60 min. Similar rates of predictive accuracy were observed for a myoglobin ratio > 2.4. The H-FABPc ratio detected successful reperfusion as early as 15 min after the onset of reperfusion and was highly accurate in detecting reperfusion within 60 min of the onset of reperfusion. The predictive accuracy of the H-FABPc ratio was similar to that of the myoglobin ratio for the early detection of successful coronary reperfusion.

Adult↗

PubMed1997

Expression of chemokine genes during rejection and long-term acceptance of cardiac allografts.

Chemokines are cytokines with chemoattractant properties for leukocytes. They may play a critical role in directing leukocytes to graft sites and in amplifying intragraft inflammation during rejection. Previous studies have tested the intragraft expression of chemokine genes during the rejection of allogeneic skin grafts in mice. In the current study, we used a heterotopic heart transplant model in mice to test the intragraft expression of these genes in nonrejecting cardiac isografts, rejecting cardiac allografts, and cardiac allografts that were accepted due to immunosuppression with gallium nitrate. With the exception of low levels of interleukin-1beta and JE, intragraft expression of the the proinflammatory cytokine genes was not observed in either isografts or native heart. Two distinct patterns of chemokine mRNA were observed in the rejecting cardiac allografts. Intra-allograft expression of interleukin-1beta, interferon-gamma-inducible protein, JE, and KC was prominent by day 3 after transplantation. The expression of macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and regulated upon activation, normal T cell expressed and secreted (RANTES) was at low or undetectable levels at day 3 after transplantation but at high levels by day 8 after transplantation. Sixty days after transplantation, intra-allograft expression of chemokines in hearts from gallium nitrate-treated recipients indicated low levels of MIP-1alpha, MIP-1beta, and KC but high levels of interferon-gamma-inducible protein and RANTES.

Animals↗

PubMed1997

Reduction of CuZn-superoxide dismutase activity exacerbates neuronal cell injury and edema formation after transient focal cerebral ischemia.

Apoptotic neuronal cell death has recently been associated with the development of infarction after cerebral ischemia. In a variety of studies, CuZn-superoxide dismutase (CuZn-SOD) has been shown to protect the brain from ischemic injury. A possible role for CuZn-SOD-related modulation of neuronal viability is suggested by the finding that CuZn-SOD inhibits apoptotic neuronal cell death in response to some forms of cellular damage. We evaluated this possibility in the model of transient focal cerebral ischemia in mice bearing a disruption of the CuZn-SOD gene (Sod1). Homozygous mutant (Sod1 -/-) mice had no detectable CuZn-SOD activity, and heterozygous mutants (Sod1 +/-) showed a 50% decrease compared with wild-type mice. Sod1 -/- mice showed a high level of blood-brain barrier disruption soon after 1 hr of middle cerebral artery occlusion and 100% mortality at 24 hr after ischemia. Sod1 +/- mice showed 30% mortality at 24 hr after ischemia, and neurological deficits were exacerbated compared with wild-type controls. The Sod1 +/- animals also had increased infarct volume and brain swelling, accompanied by increased apoptotic neuronal cell death as indicated by the in situ nick-end labeling technique to detect DNA fragmentation and morphological criteria. These results suggest that oxygen-free radicals, especially superoxide anions, are an important factor for the development of infarction by brain edema formation and apoptotic neuronal cell death after focal cerebral ischemia and reperfusion.

Animals↗

PubMed1997

Cytoplasmic gene expression system enhances the efficiency of cationic liposome-mediated in vivo gene transfer into mouse brain.

Development of methodologies for gene transfer into the central nervous system (CNS) is important for fundamental research as well as clinical studies for gene therapy. Cationic liposomes (CL) are attractive vectors because of their safety and ease of use. However, to date only low rates of success have been reported. We succeeded in obtaining high transfection efficiencies into the newborn mouse brain in vivo by CL and a cytoplasmic gene expression system based on T7 RNA polymerase and T7 RNA polymerase- and the luciferase-gene with the T7 promoter sequence. This system showed an efficiency rate 2 orders of magnitude higher than the standard system, which used CL and luciferase genes with a Rous sarcoma virus promoter, pRSVL. In addition, in vitro experiments using LLCMK2 cells showed that cytoplasmic gene expression occurred rapidly (within 6 h) after transfection. In contrast, pRSVL required 24-48 h for induction of luciferase expression. Our results suggest that the cytoplasmic gene expression system is useful for gene delivery into the CNS.

Animals↗

PubMed1997

Identification and characterization of receptor for cytokine-induced neutrophil chemoattractant-3 on rat neutrophils.

Cytokine-induced neutrophil chemoattractants (CINCs), members of alpha-chemokines, are considered to be major neutrophil chemotactic factors in rats. Recombinant CINC-3/rat macrophage inflammatory protein-2 (MIP-2) having an additional tyrosine residue at the carboxyl terminus (CINC-3-Tyr) was constructed, purified, radiolabeled with 125I, and used for binding studies. The specific binding of 125I-labeled CINC-3-Tyr (125I-CINC-3-Tyr) to rat neutrophils reached a plateau after approximately 60 min at 4 degrees C. This binding of 125I-CINC-3-Tyr could be reversed by adding an excess amount of unlabeled CINC-3-Tyr. Scatchard analysis revealed approximately 12,000 binding sites per cell on rat neutrophils with an apparent Kd value of 120 pM. Chemical cross-linking experiments suggested that the rat neutrophil CINC-3 receptor is a mass of approximately 69 kDa. Taken together, our results strongly suggest that rat neutrophils express a high affinity receptor for CINC-3.

Animals↗

PubMed1997

T cell-dependent acceleration of chemoattractant cytokine gene expression during secondary rejection of allogeneic skin grafts.

Chemoattractant cytokines, chemokines, are likely to play a critical role in directing leukocytes to graft sites and in amplifying intragraft inflammation during rejection. Since second-set graft rejection occurs at an accelerated rate, we hypothesized that chemokine genes would be expressed earlier during secondary allograft rejection than during rejection of primary allografts. We have tested this hypothesis by using Northern blot analysis to compare intragraft expression levels of genes encoding interleukin (IL) 1beta and six chemokines during rejection of C57BL/6 skin grafts on naive and C57BL/6-sensitized BALB/c recipients. Expression levels of IL-1beta, interferon-gamma inducible protein, macrophage inflammatory protein-1 (MIP-1) alpha, and MIP-1beta genes were 10- to 17-fold higher on day 5 after transplantation in C57BL/6 grafts on C57BL/6-presensitized recipients than in C57BL/6 grafts on unprimed recipients. Intragraft expression of the chemokines regulated upon activation, normal T cell expressed and secreted (RANTES), during primary C57BL/6 graft rejection was virtually undetectable at day 7 after primary transplantation, but was expressed at high levels by day 5 after secondary transplantation. In third-party CBA/Ca allografts on unsensitized and C57BL/6-presensitized BALB/c mice, similar levels of IL-1beta, MIP-1alpha, and MIP-1beta expression were observed. High levels of RANTES and interferon-gamma inducible protein expression, however, were observed at day 5 after transplantation in CBA/Ca grafts on C57BL/6-presensitized recipients and correlated with accelerated rejection of the third-party grafts. Although T cells from C57BL/6-presensitized recipients did not express increased reactivity to CBA/Ca stimulator cells in vitro, serum antibodies from these recipients demonstrated reactivity to cells from CBA/Ca and A/J mice. When compared with transfer of unprimed cells, transfer of C57BL/6-primed lymphoid cells to sublethally irradiated BALB/c mice engrafted with C57BL/6 grafts resulted in increased intragraft proinflammatory cytokine gene expression. Deletion of T cells before transfer abrogated the increased intragraft expression of proinflammatory cytokine genes. Collectively, these results indicate that the accelerated expression of chemokine genes during second-set rejection of allogeneic skin grafts is mediated by immune T cells.

Animals↗

PubMed1997

Reperfusion following focal cerebral ischemia alters distribution of neuronal cells with DNA fragmentation in mice.

To clarify the role of reperfusion in DNA damage following focal cerebral ischemia, we determined the distribution of cells with DNA fragmentation following permanent or transient focal ischemia. Less DNA-damaged cells were observed in the permanent than in the transient group in the ischemic core, but there was no difference in the boundary zone. We conclude that reperfusion following transient ischemia may exacerbate neuronal death following DNA damage.

Animals↗

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↗

PubMed1997

Apoptosis in the striatum of rats following intraperitoneal injection of 3-nitropropionic acid.

The present study investigated the mechanism of cellular degeneration within the striatum following administration of the mitochondrial toxin, 3-nitropropionic (3-NP) acid. Internucleosomal fragmentation typical of apoptosis was present in the DNA of cells from the striatum of 3-NP-treated rats. DNA fragmentation was also evident in this region by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling. The data suggest that striatal cells die by apoptosis following administration of 3-NP.

Animals↗

PubMed1997

Circadian rhythms in rapidly dividing cyanobacteria.

The long-standing supposition that the biological clock cannot function in cells that divide more rapidly than the circadian cycle was investigated. During exponential growth in which the generation time was 10 hours, the profile of bioluminescence from a reporter strain of the cyanobacterium Synechococcus (species PCC 7942) matched a model based on the assumption that cells proliferate exponentially and the bioluminescence of each cell oscillates in a cosine fashion. Some messenger RNAs showed a circadian rhythm in abundance during continuous exponential growth with a doubling time of 5 to 6 hours. Thus, the cyanobacterial circadian clock functions in cells that divide three or more times during one circadian cycle.

Cell Division↗

PubMed1997

Transformation of normal human fibroblasts into immortalized cells with the mutant p53 gene and X-rays.

In vitro cell transformation is a valuable approach for studying the mechanisms of multistep carcinogenesis of human cells. Since immortalization is an essential step for in vitro neoplastic transformation of human cells, this study addresses the question of whether mutant p53 contributes to the immortalization process of human cells. The mutant p53 gene (mp53: codon273Arg-His) was introduced into normal human fibroblasts (OUMS-24 line) and a G418-resistant clone, OUMS-24/P6 line, was obtained. This clone showed an extended life span and chromosome abnormalities, but senesced at the 79th population doubling level (PDL). When these cells were subjected to intermittent X-ray treatment, they became an immortalized cell line (OUMS-24/P6X). Although these immortalized cells showed chromosome abnormalities, they were not tumorigenic. On the other hand, normal OUMS-24 cells into which mp53 had not been introduced were not immortalized by the same X-ray treatment. These results indicate that introduction and expression of mp53 alone were not sufficient for immortalization of human cells, and that mutations of the remaining wild-type p53 or other genes may have been necessary for immortalization. In fact, no expression of the wild-type p53 was detected in the immortalized cells by RT-PCR. Expression of p21, which is located downstream of p53, was remarkably reduced in the immortalized cells, resulting in an increase in cdk2 and cdc2 kinase activity. These findings indicate that the p53-p21 cascade may play some role in the immortalization of human cells. On the other hand, there was no significant difference in expression of proteins such as Rb, p16, cdk4, cdk6, cyclin A and cyclin D1 between the normal and immortalized human fibroblasts.

Cell Transformation, Neoplastic↗

PubMed1997

Primary structures of sperm-specific basic nuclear proteins and gene expression in Japanese newt, Cynops pyrrhogaster.

Electrophoretic analyses of acid extracts from mature sperm of newt, Cynops pyrrhogaster, on acid/urea/Triton X-100 polyacrylamide gel showed the exclusive occurrence of sperm-specific nuclear basic proteins (SBPs), which moved faster than somatic histones on the gel. These SBPs were eluted separately by reversed phase-high-performance liquid chromatography as two large peaks and a few small peaks. Of these, only the small peaks disappeared with treatment of the acid extracts with alkaline phosphatase before they were injected into the column, so that there were only two distinct components: NP1 and NP2. Determination of amino acid sequences by the Edman method as well as by sequencing of cDNA for both components indicated that each protein consisted of 43 (NP1) or 48 (NP2) amino acid residues, rich in arginine residues (53.5% in NP1; 47.9% in NP2), forming the clusters. They had molecular masses of 5,386 Da (NP1) and 5,748 Da (NP2), respectively. Northern blot analysis using cDNAs as probes indicated that mRNAs for both NP1 and NP2 occurred not in primary spermatocytes but in round spermatids. In situ hybridization analyses using antisense RNA for NP1 as a probe clearly showed the first appearance of NP1 mRNA at the late stage of round spermatid.

Amino Acid Sequence↗

PubMed1997

Respiratory mechanics during mechanical ventilation: a model study on the effects of leak around a tracheal tube.

Air leak around a tracheal tube (TT) during mechanical ventilation is likely to occur during the inspiratory phase because airway pressure is high for a prolonged period. The presence of a leak may introduce errors in measurements of respiratory mechanics made at the airway opening. If so, respiratory mechanics can be measured more accurately when data are collected during the expiratory phase of ventilation. We examined this phenomenon in a lung model. When a leak was introduced into the model, simulating a leak around the TT, the leak occurred predominantly during the inspiratory phase of respiration. As the magnitude of the leak increased, the overestimation of resistance progressively increased, when calculated from pressure and flow measured at the airway opening. A large leak (38%) resulted in an overestimation of respiratory system resistance by 51% and an underestimation of elastance (Ers) by 23% when calculated from the entire ventilatory cycle. However, there was no under- or overestimation in Rrs when calculated from the expiratory phase only, and ERS was overestimated by only 6.1%. Varying peak inspiratory pressure, end-expiratory pressure, and expiratory time did influence the effect of leak, however, respiratory mechanics could still be calculated accurately from the expiratory phase under these conditions. We conclude that measurements of lung mechanics from the expiratory phase is a promising approach to dealing with the problem of measuring respiratory mechanics in mechanically ventilated infants with leaks around the tracheal tube.

Airway Resistance↗

PubMed1997

Immediate and chronic results of cutting balloon angioplasty: a matched comparison with conventional angioplasty.

BACKGROUND: At the initial stages of percutaneous transluminal coronary angioplasty (PTCA), several studies reported on the feasibility of coronary artery incision and dilatation leading to the extension of the PTCA technique. HYPOTHESIS: This study was designed to determine the immediate and chronic results of cutting balloon (CB) angioplasty. METHODS: This procedure was performed on 127 lesions in 110 patients (male 83%, age 61.8 +/- 9.3 years). RESULTS: The overall procedural success rates for the CB were 93.7% (119 lesions) and 92.7% (102 patients), while solitary CB without pre- and/or postdilatation was 76.4% (91 lesions). There was one major in-hospital complication (Q-wave myocardial infarction, 0.9%), but there were no deaths or emergency coronary artery bypass graftings. Significant angiographic dissections (> or = grade C) occurred in four patients, and coronary perforation occurred in one. The successfully treated CB group (95 lesions) was matched with the successful conventional angioplasty group (PTCA group) for chronic result assessment in regard to reference vessel size and lesion characteristics. In the CB group, postprocedural minimal luminal diameters were significantly larger and the percentage of stenosis at the stenotic site was significantly lower compared with the PTCA group. Restenosis occurred in 22 lesions (23.1%). This showed a significantly lower restenosis rate compared with the PTCA group (42.1%). In addition, the restenosis rate of the CB without inclusion of the pre- and/or postdilatation-treated lesions was 19.7%. CONCLUSIONS: (1) Cutting balloon angioplasty procedures can be performed with high success rates with few major inhospital events. (2) The restenosis rate in the CB group was significantly lower compared with the PTCA group.

Angioplasty, Balloon, Coronary↗

PubMed1997

Edema formation exacerbates neurological and histological outcomes after focal cerebral ischemia in CuZn-superoxide dismutase gene knockout mutant mice.

In a variety of studies. CuZn-superoxide dismutase (CuZn-SOD) has been shown to protect against ischemic brain injury. A possible role for CuZn-SOD-related modulation of neuronal viability has been suggested by the finding that CuZn-SOD inhibits brain edema formation following various kinds of neurological insults. We have evaluated the role of CuZn-SOD on brain edema formation following focal cerebral ischemia in mice bearing a disruption of the CuZn-SOD gene (Sod1). Homozygous mutants (Sod1-/-) had no detectable CuZn-SOD activity and heterozygous mutants (Sod1+/-) showed a 50% decrease compared to wild-type mice. Sod1-/- mice showed a high level of blood-brain barrier (BBB) disruption shortly after 1 hr of middle cerebral artery occlusion and 100% mortality at 24 hr following ischemia. Sod1+/- mice showed a moderate level of BBB disruption and 30% mortality. The Sod1+/- animals had increased infarct volume and brain swelling, accompanying exacerbated neurological deficits at 24 hr following ischemia. These results indicate the important role of superoxide anions in the development of brain edema after focal cerebral ischemia and suggest the possibility that brain edema formation may contribute to the exacerbation of ischemic brain injury and neurological deficits in knockout mutant mice.

Animals↗

PubMed1997

The mechanism of reversible osmotic opening of the blood-brain barrier: role of intracellular calcium ion in capillary endothelial cells.

Despite clinical and experimental interest in the osmotic opening of the blood-brain barrier (BBB), the mechanism underlying the phenomenon remain undetermined. The aim of this study is to investigate the mechanism of intracellular Ca2+ change in brain microvascular endothelial cells subjected to hyperosmotic stress. Cultured rat brain capillary endothelial cells were obtained by two-step enzymatic purification. Intracellular Ca2+ was measured by a confocal laser scanning microscope. After exposing the endothelial cells to 1.4 M mannitol for 30 seconds, the change of intracellular Ca2+ concentration was monitored. Intracellular Ca2+ concentration increased rapidly and reached its peak value within 10 seconds after the application of mannitol. The Ca2+ concentration returned to the basal level within 200 seconds. A calcium channel blocker nifedipine (100 microM, 10 microM) did not block the increase. A specific blocker (KB-R7943) of Na+/Ca2+ exchange did not affect the rapid elevation of intracellular Ca2+. However, it blocked the return phase almost completely. The results indicated that the Na+/Ca2+ exchanger pumped out the increased intracellular Ca2+ during the return phase. Reversible osmotic disruption and reconstruction of the BBB is not due to simple mechanical shrinkage of the endothelial cells but is due to the intracellular Ca(2+)-activated complex mechanism. The manipulation of the reconstruction phase, which depends on Na+/Ca2+ exchanger, may have clinical implications.

Animals↗

PubMed1997

Blood-brain barrier disruption, edema formation, and apoptotic neuronal death following cold injury.

The temporal pattern of brain edema and apoptosis following cold injury was investigated. Extravasation of Evans blue from the disrupted blood-brain barrier (BBB) maximized immediately after injury and returned to the control level at 24 h. However, water content increased up to 24 h and was maintained at a higher level than the control at 72 h. Apoptotic cells as detected by in situ end labeling were observed in the entire lesion at 24 h. At 72 h after injury, these apoptotic cells were observed in the margin of the lesion, but not in the core. These results suggest that apoptosis contributes to neuronal damage following cold injury and may result from the development of vasogenic edema.

Animals↗

PubMed1997

Blood-brain barrier disruption, HSP70 expression and apoptosis due to 3-nitropropionic acid, a mitochondrial toxin.

3-Nitropropionic acid (3-NP), a mitochondrial toxin, induces apoptosis in the striatum. We wanted to determine if there was a relationship between mitochondrial dysfunction, disruption of the blood-brain barrier (BBB), and apoptosis. BBB disruption following intrastriatal injection of 3-NP was assessed by Evans blue leakage, brain water content, and by the expression of the 70 kDa heat shock protein (HSP70) and mRNA. Apoptosis was assessed by in situ terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end labeling (TUNEL) and gel electrophoresis to detect internucleosomal DNA fragmentation. Microscopic evidence of Evans blue leakage due to 3-NP was present only 3 hr after injection. Both internucleosomal DNA fragmentation and TUNEL-labeling did not appear until 24 hr after injection. HSP70 (protein and mRNA) was also elevated by 24 hr. There was a quantitative increase in Evans blue leakage and brain water content due to 3-NP by 3 days after injection. Our results suggest that BBB disruption is an early event followed by increased HSP70 expression and apoptosis. We speculate that 3-NP damages endothelial cells, leading to vasogenic edema and apoptosis.

Animals↗