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T Toyoshima

Publications and source records attributed to T Toyoshima.

At least 19 recordsLinked to original sources
PubMed1998

Entactin-2: a new member of basement membrane protein with high homology to entactin/nidogen.

Using the new signal sequence trap (SST) method, we isolated several clones encoding secreted and transmembrane proteins from KUSA cells, a murine osteoblast-like cell line. One isolated novel clone, termed entactin-2, exhibited a high similarity to mouse entactin/nidogen, a basement membrane protein. Although deduction of the amino acid sequence of entactin-2 revealed only 27.4% homology to entactin, many structural similarities were seen between both proteins. Entactin-2 contains five EGF-like and two thyroglobulin-like motifs, which are both cysteine-rich. Comparison of both proteins clearly revealed that entactin-2 also contains related domain structures. The rod-like domain of entactin-2, containing the RGD integrin recognition sequence, fused to glutathione-S transferase (GST), revealed a cell surface-binding activity similar to that of entactin. In addition, the tissue distribution of entactin-2 mRNA resembled that of entactin. Furthermore, mRNA expression of both genes decreased as osteoblastic differentiation progressed. These results suggest that entactin-2 is a member of the entactin gene family, may have entactin-related functions, and might act as a basement membrane component.

Amino Acid Sequence↗
PubMed1998

Germ-cell degeneration in experimental unilateral cryptorchidism: role of apoptosis.

We investigated the possible involvement of apoptosis in the increased germ-cell degeneration in undescended testes (UDT). Experimental unilateral cryptorchidism was induced in 21-day-old rats, and both testes were removed for in-situ TUNEL staining of apoptotic cells at 1, 3, 7, 10, and 14 days postoperation. A gradual increase in the incidence of apoptosis was seen at 21-28 days of age in the control testes, followed by a decrease thereafter. After 10 days postoperation, the weight of the UDT was significantly lower than that of the contralateral descended testis (CDT) and the controls. However, the weight of scrotal testes in each group was similar. UDTs demonstrated a markedly increased incidence of apoptosis. By 7 days postoperation, the percentage of seminiferous tubules containing apoptotic germ cells significantly increased in UDTs compared with that in CDTs and controls (P < 0.001). Moreover, there was a significant difference in the percentage of seminiferous tubules containing apoptotic germ cells between CDTs and controls (P < 0.01). In addition, an increased incidence of seminiferous tubules containing 8-10 and >10 apoptotic germ cells from 7, 10, and 14 days postoperation in UDTs was detected. In-situ TUNEL analysis demonstrated spermatocytes to be the main type of germ cells affected in all groups. These findings suggest that spermatogenesis decreases not only in the UDT, but also in the CDT, and that the germ-cell degeneration in cryptorchidism took the form of apoptosis.

Animals↗
PubMed1998

Specific inhibition of apoptosis after cold-induced brain injury by moderate postinjury hypothermia.

OBJECTIVE: Apoptosis of neuronal cells plays a key role in many developmental and pathological processes of the central nervous system. Deoxyribonucleic acid (DNA) of cells undergoing apoptosis is cleaved by an endonuclease into oligonucleosoma-sized fragments. These fragments can be labeled using in situ terminal deoxynucleotidyl transferase so that the apoptotic cells can be visualized by in situ apoptotic staining. The model of cold-induced rat brain edema was used to further examine this hypothesis. The protective effect of hypothermia was also studied in this model of cold-induced brain injury. METHODS: Using a terminal deoxynucleotidyl transferase-mediated deoxyuridine 5'-triphosphate-biotin nick end labeling technique, the neuronal cells with DNA fragmentation in different regions of the brains of rats subjected to cold-induced brain injury were detected. The internucleosomal fragments of DNA in apoptotic cells were examined using agarose gel electrophoresis. The animals were randomly divided into three groups: 1) sham (n = 8); 2) cold-induced brain injury, killed at 12, 24, 48, 72, and 168 hours after cold lesion (n = 10 for each time point); 3) hypothermia, both mean temporalis and rectal temperatures were reduced by surface cooling to 32 degrees C (standard deviation, 0.1 degrees C) for 3, 6, and 12 hours (n = 10 for each time point) beginning 1 hour after cold-induced brain injury. RESULTS: The apoptotic cells were detectable for up to 72 hours after the initial brain injury and reached a peak at approximately 24 to 48 hours, with a mean peak value of 24.29 +/- 5.26, 15.37 +/- 4.10, 15.81 +/- 3.56, 13.94 +/- 2.48, 10.46 +/- 2.23, and 7.68 +/- 2.48% in the cortex, subcortex, white matter, CA1, CA3, and dentate gyrus, respectively, and had a significant increase, compared with the control value (mean +/- standard error, P < 0.01). Agarose gel electrophoresis of DNA extracted from cortex and hippocampus containing apoptotic cells revealed a "DNA ladder" at 180- to 200-base pair intervals. In animals subjected to the same brain injury that underwent 32 degrees C hypothermia, the numbers of apoptotic cells were reduced evidently and DNA fragmentation was inhibited. CONCLUSION: The data suggest that apoptosis occurs after cold-induced brain injury and that DNA fragmentation may be associated with apoptotic cell death. Moderate hypothermia shows specific effect on inhibition of apoptotic cell death and cellular DNA fragmentation after cold-induced brain injury in rats.

Animals↗
PubMed1998

Coronary flow velocity patterns immediately after reperfusion reflect the pathologic characteristics of reperfused myocardium in canine models of acute myocardial infarction.

BACKGROUND: It is difficult to evaluate the extent of myocardial injury after successful reperfusion following acute myocardial infarction (AMI). We investigated the relationship between the coronary flow velocity pattern immediately after reperfusion and pathologic characteristics after myocardial reperfusion injury in dogs. METHODS: We measured distal coronary flow velocity variables in the left circumflex coronary artery in a canine model of AMI (n = 12) 10 min after the release of a clamp (3-10 h clamp procedure) using a 0.35 mm Doppler guide-wire. Dogs were divided into two groups according to presence or absence of early systolic retrograde coronary flow. Hearts were excised 2 h after reperfusion and examined histopathologically. RESULTS: The clamping time tended to be longer in dogs with early systolic retrograde coronary flow. Neutrophil infiltration was observed in the myocardium of dogs without systolic retrograde flow (n = 9); hemorrhage was rarely detectable and the myocardium maintained a bundle form. However, the bundle form of the myocardium became rough, and the severity of the incidence of hemorrhage tended to increase as the ratio of the diastolic coronary flow velocity to systolic velocity (DSVR) decreased. Vacuolar degeneration of the myocardium was also observed in hearts with a relatively low DSVR. In the group with systolic retrograde flow (n = 3), hearts were characterized by coagulation necrosis, marked vacuolar degeneration of the myocardium and diffusely distributed red cells in the intermyocytes. Systolic antegrade flow velocity was much reduced in this group, resulting in a markedly increased DSVR. These findings appeared to be related to severe myocardial damage. CONCLUSIONS: Coronary flow velocity patterns immediately after successful reperfusion appear to reflect the pathologic characteristics of the reperfused myocardium in dogs with AMI.

Animals↗
PubMed1998

Neurotoxicity of Clostridium perfringens epsilon-toxin for the rat hippocampus via the glutamatergic system.

The neurotoxicity of epsilon-toxin, one of the major lethal toxins produced by Clostridium perfringens type B, was studied by histological examination of the rat brain. When the toxin was injected intravenously at a lethal dose (100 ng/kg), neuronal damage was observed in many areas of the brain. Injection of the toxin at a sublethal dose (50 ng/kg) caused neuronal damage predominantly in the hippocampus: pyramidal cells in the hippocampus showed marked shrinkage and karyopyknosis, or so-called dark cells. The dark cells lost the immunoreactivity to microtubule-associated protein-2, a postsynaptic somal and dendric marker, while acetylcholinesterase-positive fibers were not affected. Timm's zinc staining revealed that zinc ions were depleted in the mossy layers of the CA3 subfield containing glutamate as a synaptic transmitter. The cerebral blood flow in the hippocampus was not altered significantly before or after administration of the toxin, as measured by laser-Doppler flowmetry, excluding the possibility that the observed histological change was due to a secondary effect of ischemia in the hippocampus. Prior injection of either a glutamate release inhibitor or a glutamate receptor antagonist protected the hippocampus from the neuronal damage caused by epsilon-toxin. These results suggest that epsilon-toxin acts on the glutamatergic system and evokes excessive release of glutamate, leading to neuronal damage.

Animals↗
PubMed1997

Localization of calbindin-D28k in normal and incised mouse skin: immunohistochemical and immunoblot analysis.

The subcellular localization of the protein calbindin-D28k in normal and incised mouse skin was investigated by immunohistochemical staining and immunoblot analysis. In normal skin, the presence of calbindin-D28k was demonstrated in both the nucleus and the cytoplasm of epidermal keratinocytes. Higher levels of calbindin-D28k were detected in the nucleus than in the cytoplasm. Following incision, the levels of calbindin-D28k were significantly decreased in epidermal keratinocytes, particularly in the nucleus, compared with those in normal skin. The immunohistochemical staining and immunoblot analysis showed nuclear calbindin-D28k to be decreased or absent during a 10-day observation period following skin incision. Based on these findings, it is suggested that calbindin-D28k may be distributed in both the nucleus and cytoplasm of epidermal keratinocytes in mice, and this protein may be involved in active cell proliferation of the epidermis induced by skin incision.

Animals↗
PubMed1997

[Combination use of second generation cephem and isepamicin for the treatment of post-surgical infection of the lower digestive tract].

Effects of combination use of a second generation cephem and an aminoglycoside antibiotic isepamicin (ISP), for the treatment of post-surgical infections of the lower digestive tract were examined from a laboratory and clinical perspective. Thirty-three out of total 35 cases were included in the analysis of the test, while the other 2 cases did not meet the criteria for analysis. ISP was administered in combination with one of the second generation cephems among cefotiam (CTM), cefmetazole (CMZ), or cefuroxime (CXM) for 26 cases of wound infection and 7 cases of peritonitis. The overall efficacy rate was 88%; 92% in wound infection and 71% in peritonitis individually. There was no significant difference in efficacy among different groups. Bacteriological study showed the combination use of any one of the second generation cephems and ISP was very effective in all 14 cases of infections with a single species of bacterium, the efficacy rate was 100%. It was also effective in 9 out of 10 cases with mixed infections of 2 species of bacteria (90%), but effectiveness was diminished in only 6 out of 9 cases with mixed infections of 3 species (67%). Sixty-nine strains were isolated from the 35 cases, more than half of which (44 strains) were Gram-negative; 14 strains of E. coli (20%), 13 strains of E. faecalis (13%) and 6 strains of P. aeruginosa (9%). The MIC50 and MIC90 were, respectively, 1.56 micrograms/ml and 100 micrograms/ml for ISP, 6.25 micrograms/ml and 100 micrograms/ml for CTM, 12.5 micrograms/ml and 100 micrograms/ml for CMZ, and 25 micrograms/ml and 100 micrograms/ml for CXM. The MICs in any combination uses decreased synergistically according to ISP concentration. Adverse events were observed in 3 out of 35 cases, but they were not severe. The results indicated that the combination use of a second generation cephem and ISP was useful and should be one of the choices for the treatment of post-operative infections of the lower digestive tract.

Adult↗
PubMed1996

Expression of calbindin-D28K by reactive astrocytes in gerbil hippocampus after ischaemia.

Calbindin-D28K (Calbindin) is a member of the superfamily of calcium-binding proteins that is implicated in the regulation of intracellular calcium. In the adult mammalian brain, calbindin was thought to be present only in neurones, where it is believed to serve a neuroprotective role. We now report the expression of calbindin after ischaemia in reactive astrocytes in the CA1 subfield of the hippocampus. Since other calcium-binding proteins, such as S-100 and calmodulin, which induce transformation or proliferation of glia, occur in astrocytes, it is conceivable that the expression of calbindin after ischaemia might be an important part of the process of gliosis.

Animals↗
PubMed1996

A chronological study of the expression of glial fibrillary acidic protein and calbindin-D28 k by reactive astrocytes in the electrically lesioned rat brain.

Immunoreactivity of neuronal and glial marker proteins of reactive astrocytes around the electrically damaged pyramidal layer and stratum radiatum of the hippocampal CA1 region and corpus callosum was chronologically studied in electrically lesioned rat brains. A monoclonal antibody against calbindin-D28 k (CD28-Ab) and a polyclonal antibody against glial fibrillary acidic protein (GFAP-Ab) were used for immunostaining. Immunoreactivity of CD28 and GFAP in the reactive astrocytes was detected in brains 1-6 weeks post-lesion but not in non-lesioned brains. The number of immunohistochemically stained reactive astrocytes around the electrically damaged areas were counted and then compared with the number of those in the same areas of non-lesioned brains. The number of CD28- and GFAP-immunoreactive astrocytes began to increase around the lesion from 1-3 weeks following lesion in the pyramidal layer of the hippocampal CA1 region and from 1-4 weeks following lesion in the stratum radiatum of the hippocampal CA1 region and corpus callosum. These immunoreactive astrocytes could be observed for 6 weeks (the maximum survival time studies) in all areas of the lesioned brains studied. The increase in the number of reactive astrocytes might have been induced by the stimulatory effects of neurotrophic factors, or growth factors, produced around the lesioned site. The constancy in the number of reactive astrocytes after 3 and 4 weeks in the lesioned areas may have been due to the termination of the initial phase of the repair process, i.e. space-filling. Reactive astrocytes which were stained by GFAP-Ab were separated into two groups, based on the presence of CD28, i.e. CD28-positive and CD28-negative reactive astrocytes. The presence of CD28 might confer certain functions via calcium-mediated mechanisms on CD28-positive astrocytes in addition to the constructive role mediated by GFAP.

Animals↗
PubMed1996

Presence of hematopoietic stem cells in the adult liver.

Recently, cases have been reported in which a mixed chimeric state of blood cells is established after liver transplantation. Because the established chimerism may have aided in the induction of donor-specific tolerance, the mechanism responsible for this chimerism is of clinical importance. To establish this, we examined cells in adult mouse liver and identified the presence of c-kit+ Sca-1+ Lin(lo/-) cells. These cells were capable of forming in vivo as well as in vitro colonies. Furthermore, the cells could reconstitute bone marrow of lethally irradiated recipient mice for at least 12 months. These data obtained from the mouse study strongly suggest that hematopoietic stem cells residing in the donor liver are responsible for mixed chimerism and maintenance of tolerance after liver transplantation.

Animals↗
PubMed1996

[The effect of ACE inhibitors, beta blockers and calcium antagonists on the responses to pressor stress tests in the elderly hypertensive patients].

The purpose of the study was to elucidate the effects of antihypertensive drugs on the hemodynamics in elderly hypertensive patients. Forty-two elderly hypertensives (mean 72 +/- 5 years) were given either ACE inhibitors (A group: perindopril in 10 and captopril in 4 cases), beta blockers (B group: arotinolol in 15 cases) or calcium antagonists (C group: nifedipine in 3 and nitrendipine in 10 cases) for 8-12 weeks. The responses to handgrip and mental arithmetic stress and cardiac functional changes were determined by echocardiography before and after the medications. The decrease in blood pressure at rest and on the stress tests was similar among the three groups, though the hemodynamic responses to the stress tests showed some differences. In the A group, no hemodynamic changes were seen either at rest or on the stress tests after the medication. In the B group, the heart rate and the cardiac output were decreased at rest, and the increase of them on the stress tests were diminished after the medication. On the contrary, the heart rate and the cardiac output were increased, and showed exaggerated responses on the stress tests in the C group. In conclusion, in antihypertensive treatment of elderly hypertensive patients it is important to consider the effects of the antihypertensive drugs on the hemodynamics, although the comparable decrease in blood pressure is expected.

Adrenergic beta-Antagonists↗
PubMed1996

[Circadian variation in blood pressure in elderly hypertensive patients].

We studied circadian variation in blood pressure in elderly patients with hypertension, using three criteria for "non-dipper". Ambulatory blood pressure monitoring was done in 107 elderly outpatients whose average 24-hour systolic blood pressure was greater than 140 mmHg. Daytime was distinguished from nighttime by the level of physical activity as measured with an activity sensor and a questionnaire. The three criteria for "non-dipper" were as follows: 1. A nocturnal decline in systolic blood pressure that was less than 10% of the daytime average blood pressure. 2. A nocturnal decline in systolic blood pressure that was less than 10 mmHg. 3. A nighttime average systolic blood pressure that was greater than the daytime average systolic blood pressure. The nocturnal decrease in blood pressure was smaller in older patients than in younger patients. In patients over 80 years old, it was 6.0 mmHg (p < 0.05, as compared with patients aged 60-69 and with patients aged 70-79). The percentages of patients classified as "non-dippers" according to the criteria listed above were 53.3%, 37.4%, and 15.9%, respectively. Older patients were more likely than younger patients to be classified as "non-dippers". When defined according to criterion # 1, "non-dippers" made up 83.3% of those over 80 years old. These results was consistent with a continuous age-related decline in neuroendocrine regulation involving both peripheral and central nervous system.

Aged↗
PubMed1996

[The relationship between office and ambulatory blood pressure in elderly patients in a non-academic setting].

We investigated the relationship between clinic blood pressure (BP) and ambulatory blood pressure (ABP) in 297 elderly patients who underwent 24 hour ABP monitoring as a non-academic clinical references. Among 107 cases who were normotensive in office BP measurements, 33 cases (30.8%) proved to be hypertensive with more than 140 mmHg in ambulatory systolic BP. Those patients should be referred to as home hypertension or white coat normotension. On the other hand, among 187 patients who were hypertensive in the clinic, 78 cases (41.7%) turned out to be white coat hypertension with an ambulatory daytime systolic BP of less than 140 mmHg. Ambulatory systolic BP in white coat hypertension was comparable with that in the non-hypertensive group although their BP in the clinic was significantly higher than the latter (p < 0.02). Ambulatory systolic BP in the home hypertension group was significantly higher than that in the normotension but was comparable with that in true hypertension. The number of the antihypertensive drugs prescribed in the white coat hypertensive group tended to be greater than that in other groups although that in the home hypertensive group was similar to the other groups. The incidence of cerebro vascular disease in each group was similar.

Aged↗
PubMed1995

Plasmodium yoelii: 17-kDa hepatic and erythrocytic stage protein is the target of an inhibitory monoclonal antibody.

Infected hepatocytes are important targets for malaria vaccines. To identify Plasmodium yoelii proteins expressed in infected hepatocytes, we immunized BALB/c ByJ mice with P. yoelii liver stage schizonts and produced a panel of monoclonal antibodies (Mabs). An IgG1 Mab, navy yoelii liver stage 3 (NYLS3), had the strongest reactivity against liver stage parasites and was selected for further characterization. The Mab does not recognize P. yoelii sporozoites, but recognizes liver stage parasites within 6 hr of invasion of mouse hepatocytes and throughout the hepatic and asexual erythrocytic stages of the parasite life cycle as determined by the immunofluorescent antibody test. This Mab is species-specific, and it reacts with liver stages of P. yoelii but does not react with liver stages of other Plasmodium species. The protein recognized by this Mab is present on the parasitophorous vacuole membrane of infected hepatocytes and erythrocytes as demonstrated by immunoelectron microscopy and has a relative molecular weight of 17 kDa as demonstrated by immunoblot of an extract of infected erythrocytes. It is therefore designated P. yoelii hepatic and erythrocytic stage protein, 17 kDa or PyHEP17. When added to primary cultures of mouse hepatocytes 24 hr after inoculation with P. yoelii sporozoites, when all sporozoites have invaded hepatocytes, NYLS3 eliminates up to 98% of liver-stage parasites. Intravenous injection of NYLS3 into mice delays the onset and reduces the density of blood-stage parasitemia after sporozoite or blood-stage challenge. The P. falciparum and P. vivax homologs of PyHEP17 may therefore be important targets for vaccines designed to attack the hepatic and erythrocytic stages of the parasite life cycle.

Animals↗
PubMed1995

Urachal adenocarcinoma accompanied by a large spherical calcified mass.

We report a case of urachal adenocarcinoma, accompanied by a large spherical calcified mass adherent to the bladder dome of a 63-year-old man. The patient underwent partial cystectomy including en bloc resection of the urachus, and remains free from the disease after a 32-month follow-up period.

Adenocarcinoma↗
PubMed1994

Plasmodium falciparum: the Pf332 antigen is secreted from the parasite by a brefeldin A-dependent pathway and is translocated to the erythrocyte membrane via the Maurer's clefts.

The transport of the megadalton protein Pf332 was studied during the asexual bloodstage development of Plasmodium falciparum. Four mouse monoclonal antibodies, produced against a recombinant polypeptide derived from the Pf332 protein, were used to analyze the kinetics of synthesis, the subcellular location, and transport of this giant molecule to the erythrocyte membrane. After parasite invasion of a red blood cell, the Pf332 antigen is first detected in young trophozoites at the parasitophorous vacuole membrane or in the cytoplasm of the erythrocyte as large vesicle-like structures. The number of vesicles increases during maturation of the parasite and thus forms a rim-like immunofluorescence pattern between the erythrocyte membrane and the parasitophorous vacuole at very late stages. The various anti-Pf332 antibodies react with the surface of erythrocytes infected with very mature parasites (segmenter stage 42-46 hr postinvasion). Immunoelectron microscopic analysis shows that the Pf332 antigen is transported in association with Maurer's clefts in the cytoplasm of the erythrocyte. This transport could be completely blocked by Brefeldin A, resulting in the accumulation of the antigen within the parasite. These data strongly suggest that the Pf332 antigen is exported to the erythrocyte cytoplasm via the classical Golgi secretory pathway.

Animals↗