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Biomedical subjects

H Suda

Publications and source records attributed to H Suda.

At least 163 records · Page 9Linked to original sources
PubMed1995

Plasma endotoxin in typhoid fever.

Plasma endotoxin contents of the patients with sepsis or typhoid fever were measured by two sophisticated chromogenic limulus tests; Endospecy and Toxicolor tests. Endospecy test is the endotoxin-specific test and Toxicolor is responsible for both endotoxin and (1,3)-beta-D-glucan. Plasma was pretreated by our new PCA method which resolved the problem as to the detection of a lesser amount of plasma endotoxin when pretreated by the conventional PCA method. Although Toxicolor values have been reported to exceed more than the Endospecy value, under complicated pathophysiological situations, almost all specimens of these patients had a similar value, except in one expired septic shock case. In 18 typhoid fever cases, Salmonella typhi was isolated only from the bile in 5 cases, however endotoxemia occurred in 11 cases (61.1%). Within the first 4 days, the incidence of endotoxemia was higher (10/14, 71.4%). These results suggest that endotoxin assay seemed to be a useful tool for the diagnosis of typhoid fever.

Bacteremia↗
PubMed1994

Experimental study and clinical observations on hypertrophy of vascularized bone grafts.

In order to understand the mechanisms involved in the hypertrophy of vascularized bone grafts, a series of animal experiments were carried out and 32 clinical cases were studied. A defect in the tibial shaft was created in puppies and the ipsilateral fibula was transferred into the medullary cavity of the tibia with the anterior tibial artery and vein. The same procedure was performed on a control group but without vessel supply. Radiologically, in the vascularized group mild hypertrophy in the fibula was seen at 2 weeks, became marked by 4 weeks, but in no case did the thickening (hypertrophy) of the graft ever exceed the diameter of the recipient tibia. The control group did not show hypertrophy but fracture callus formed in the recipient tibia at both ends of the graft. On histological evaluation no reactive bone formation was evident in the control group but some reactive bone formation was seen in the vascularized group just beneath the periosteum. There was no change in the periosteum itself. In the clinical cases 47% of patients showed hypertrophy. Hypertrophy was noted mainly in the fibulae but rarely in other bones such as ilium or rib. The important factors were age and good vascularity of the grafted bone. During the period of study, weight-bearing was eliminated, so that the effects of mechanical force did not explain hypertrophy. We conclude from these studies that true hypertrophy is an essentially different process from reactive callus which forms normally in response to fracture healing. Vascularized bone grafts show remarkable hypertrophy of the grafted bone, but the exact mechanism is ill defined.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Spinal cord protection: development of a paraplegia-preventive solution.

We present a clinically available method to protect the spinal cord against ischemic or reperfusion injury and to prevent paraplegia after cross-clamping of the aorta. We separated 35 rabbits into five equal groups and clamped each animal's abdominal aorta distal to the left renal artery. We also occluded the aortas 2 cm above the iliac bifurcation for 45 minutes with inflated 5F balloon catheters. Through the catheter port distal to each balloon one of four different solutions was infused at 3 degrees C for 3 minutes at a rate of 5 mL/min (group I, uninfused control; group II, lactated Ringer's solution; group III, lactated Ringer's solution + 30 mg/kg of methylprednisolone; group IV, lactated Ringer's solution+methylprednisolone + 3 mL of 20% mannitol; group V, lactated Ringer's solution+methylprednisolone+mannitol + 10 mg/kg of vitamins E and C). We assessed the neurologic status of the hind limbs on the second postoperative day using Tarlov's criteria. The neurologic status in groups III, IV, and V was significantly superior to that of group I (p < 0.05, groups III versus I; p < 0.01, groups IV and V versus I). Spastic paraplegia occurred in 71% of group I, in 43% of group II, in 29% of group III, in 14% of group IV, and not at all in group V. The infusion of our specially blended solution with several spinal cord neuroprotective properties (hypothermia, methylprednisolone, mannitol, and vitamins E and C) achieved the best spinal cord protection against ischemic or reperfusion injury and prevented postoperative paraplegia.

Animals↗
PubMed1994

Induction of oral tolerance after feeding of ragweed pollen extract in mice.

The induction of oral tolerance following the feeding of ragweed pollen and its extract was investigated in BALB/c mice. Antibody class-specific immune suppression could be observed, and the IgE response was specifically suppressed, depending on the amount of ragweed pollen extract fed when subsequently immunized with ragweed extract together with A1(OH)3 as an adjuvant. A multiple feeding was more effective than a single feeding of antigen, and the IgE response was completely suppressed when 20 mg of pollen extract was fed for 5 consecutive days. On the other hand, IgG production was not suppressed even though a large amount of ragweed pollen or its extract was fed. Furthermore, no secretion of antigen-specific IgA into saliva was observed in control animals or those fed ragweed pollen extract. Thus, pollen extract feeding may be potentially useful for the prophylaxis or therapy of allergic rhinitis induced by ragweed.

Administration, Oral↗
PubMed1994

Distribution of Ia antigen-expressing nonlymphoid cells in various stages of induced periapical lesions in rat molars.

Periapical lesions were experimentally produced in rat lower first molars by exposing the pulp to the oral environment for 1 to 56 days. Temporal changes in the number and distribution of la antigen-expressing nonlymphoid cells in the periapical tissue were examined immunohistochemically on decalcified cryostat sections using OX6, a monoclonal antibody against rat la antigen. Influx of la-positive exudative cells into the periapical tissue was observed from 1 day postoperatively. Between 14 and 28 days when expansion of the periapical lesion was most evident, numerous la-positive macrophage-like and dendritic cell-like cells of diverse morphologies were found in the periapical tissue. The number of these cells showed further increase at 56 days postoperatively, when the lesion expansion had ceased. These results suggest the involvement of la antigen-expressing nonlymphoid cells in the development and perpetuation of periapical pathosis. They may act primarily as antigen-presenting cells, which are essential for the initiation of antigen-specific immune defense.

Animals↗
PubMed1994

New electronic canal measuring device based on the ratio method.

The most striking disadvantage of most apex locators is that if there are electrolytes in the canal the meter shows a reading which is too short or sometimes the measurement itself becomes impossible. To overcome this drawback, a new concept for electrically measuring the root canal length has been developed. The device simultaneously measures two impedances of the canal using current sources with two different frequencies. Then the ratio between the two electric potentials proportional to each impedance is calculated. The quotient is shown on the device's meter and represents the position of a file tip in the canal. The present study found that the quotient was only negligibly influenced by the electrolyte present in the canal and decreased considerably as the file tip approached the apical foramen.

Dental Pulp Cavity↗
PubMed1994

Indirect longitudinal cytotoxicity of root canal sealers on L929 cells and human periodontal ligament fibroblasts.

The cytotoxicity of two root canal sealers was evaluated in vitro. The powder components of both sealers, mainly zinc, were the same. The liquid for one sealer, Canals, was clove oil (included eugenol in more than 80%) and other materials. For the other, Canals-N, the liquid was composed of higher fatty acids and glycol. The experiments included two cell lines, heteroploid L929 mouse fibroblasts and diploid human periodontal ligament fibroblasts. Cytotoxicity was assessed using the radiochromium release method with 4-h exposure time. The assay involved using insert chambers in multiwell arrays to produce indirect contact of materials with the cell monolayer at a controlled distance of approximately 1 mm. This model also allowed for the longitudinal study of the same material sample to assess time-dependent changes in toxicity. Freshly mixed Canals was highly toxic (p < 0.01) to both cell lines. On and after 24 h of setting no toxicity was detected. At no time could cytotoxicity be observed when experimenting with Canals-N. These results indicate that both materials have a low content of water diffusible toxic components. Substituting eugenol can further decrease the toxicity of the sealer.

Animals↗
PubMed1994

Inhibition of topoisomerase II by a novel antitumor cyclic depsipeptide, BE-22179.

BE-22179, a novel cyclic depsipeptide antibiotic having two 3-hydroxyquinoline moieties, inhibited the DNA-relaxing activity of L1210 topoisomerase II completely at 0.08 microM. This effect was far stronger than that of VP-16. However, it did not show any marked effect on topoisomerase II-mediated DNA cleavage. BE-22179 was ineffective in inhibiting the DNA relaxation by topoisomerase I at concentrations up to 10 microM, but showed DNA-intercalating ability (DNA unwinding) at 30 microM. The structure of BE-22179 is quite novel for a topoisomerase II inhibitor. Echinomycin, a quinoxaline antibiotic structurally related to BE-22179, interfered with DNA relaxation by topoisomerase II, though the effect was not due to inhibition of the catalytic activity of topoisomerase II but to conformational change of DNA based on its intercalation into DNA. Therefore, the potent inhibitory activity on topoisomerase II might not be a common activity of quinoxaline antibiotics, but might rather be specific to BE-22179. BE-22179 prevented DNA synthesis as well as RNA synthesis in L1210 cells and inhibited the growth of the cells. However, it remains unclear to what extent the topoisomerase II inhibition was responsible for the cytotoxicity of BE-22179.

Animals↗
PubMed1994

A new topoisomerase II inhibitor, BE-22179, produced by a streptomycete. I. Producing strain, fermentation, isolation and biological activity.

A new topoisomerase II inhibitor, designated BE-22179, was isolated from the culture broth of Streptomyces sp. A22179, which resembles "Streptomyces gangtokensis". The inhibitor was extracted from the mycelial cake of the culture broth with organic solvent and successively purified by silica gel chromatography. BE-22179 inhibited topoisomerase II strongly but not topoisomerase I and showed potent antitumor activity against various tumor cell lines both in vitro and in vivo.

Animals↗
PubMed1994

BE-23372M, a novel protein tyrosine kinase inhibitor. I. Producing organism, fermentation, isolation and biological activities.

BE-23372M, a novel protein tyrosine kinase inhibitor, was isolated from the culture broth of a fungus. The producing strain, F23372, was identified as Rhizoctonia solani, based on the cultural and morphological characteristics. The active principle was extracted from the mycelium with acetone and purified by solvent extraction, silica gel column chromatography and Sephadex LH-20 column chromatography. BE-23372M showed strong inhibitory activity against EGF receptor kinase with IC50 values of 0.02 and 0.03 microM on two different substrates, whereas IC50 values against protein kinase C and cAMP-dependent protein kinase were 4.5 and > 20 microM, respectively. The compound inhibited the growth of A431 human epidermoid carcinoma and MKN-7 human stomach cancer cell lines with IC50 values of 8 and 24 microM, respectively.

Amino Acid Sequence↗
PubMed1994

BE-23372M, a novel protein tyrosine kinase inhibitor. II. Physico-chemical properties and structure elucidation.

BE-23372M, a new protein tyrosine kinase inhibitor, has been obtained as a reddish orange solid. The compound, C17H12O6, HRFAB-MS: m/z 312.0625 (M)+, is an acidic substance, showing UV (MeOH) lambda max (epsilon) 266 (8,800), 426 nm (20,400), and IR (KBr)vmax 1752(C = O) and 3298(OH) cm-1. The structure of BE-23372M, (E)-3-(3,4-dihydroxybenzylidene)-5-(3,4-dihydroxyphenyl)-2(3H)-fur anone, has been elucidated by 1H and 13C NMR studies.

Chromatography, Thin Layer↗
PubMed1994

[Replacement of distal arch aneurysm: distal hemiarch replacement].

Among thoracic aortic aneurysm, operative result for distal arch aneurysm is poor. Approach auxiliary technique, and operative procedure are still controversial. We noticed that distal arch aneurysm frequently involve anterior lesser curvature of aortic arch, then we have designed "distal hemiarch replacement" that preserve branches of aortic arch and replace lesser curvature of arch sufficiently. Furthermore, we managed to prevent cerebral injury by atheromatous embolism using intraoperative echogram to detect atherosclerosis of aortic arch and the branches. Median approach, selective cerebral perfusion, and distal hemiarch replacement were performed consistently for seven distal arch aneurysm. As the result, all cases recovered without neurological deficit except one ruptured emergency case. Distal hemiarch replacement for distal arch aneurysm enabled sufficient essential removal and reconstruction of the thoracic aorta with minimal invasion. Intraoperative echogram could reduce operative cerebral injury and brought sufficient operative results.

Aged↗
PubMed1994

[A case of chronic traumatic thoracic aneurysm after an injury 18 years ago].

Chronic traumatic thoracic aneurysm which had passed over eighteen years since injury was reported. A 41-year-old man, who was involved in automobile accident 18 years before, complained back pain and was referred to our hospital for an aneurysm at the aortic isthmus. According to his history of trauma and location of aneurysm, it was diagnosed as chronic traumatic thoracic aneurysm. Graft replacement was performed under the left heart bypass by using the BioMedicus centrifugal pump. He has been doing well after the operation.

Adult↗
PubMed1994

[A successful case report of coronary artery bypass grafting under ventricular fibrillation with circulatory arrest].

Coronary artery bypass grafting in a 78-year-old female with severely calcified ascending aorta was performed successfully. Bilateral internal thoracic arteries and saphenous vein were anastomosed under ventricular fibrillation and hypothermia without aortic cross-clamping. Proxymal anastomosis of saphenous vein graft was performed directly under circulatory arrest in a normal part of ascending aorta which was confirmed by intraoperative ultrasonography. Weaning from ECC was easy and no neurological complication was observed after operation. Bypass grafts were patent on postoperative coronary angiogram and postoperative course was uneventful. We think the technique of circulatory arrest and intraoperative ultrasonography were useful in a patient with severely calcified ascending aorta.

Aged↗
PubMed1993

Intermolecular forces between the motor protein and the filament.

Intermolecular forces between motor proteins and filaments were evaluated on the basis of the experimental data of an in vitro motility assay by considering the molecular friction in the movement system. The molecular friction was caused by a different mechanism from that of the hydrodynamic drag. However, the molecular frictional forces apparently gave the same expression as the hydrodynamic frictional forces. The resulting equation was very effective in examining the physical properties of the weak interaction in the dynein-microtubules system from basic experiments carried out by Vale et al. (1989). From careful analysis of their experimental data, it was concluded that the hydrodynamic friction was not dominant, even in the weak binding state. The electrostatic interaction between dynein-heads and microtubules in the weak binding state was analyzed by applying the DLVO (Derjaguin-Landau-Verway-Overbeek) theory in colloid science through the ionic dependence of one-dimensional diffusion. The interacting distance between charges which took part in the weak adhesion was estimated to be 3 nm. In the present study, the molecular mechanism of the sliding velocity was also investigated for the myosin-actin filaments and the kinesin-microtubules systems by fitting the ATP-dependence and the ionic dependence in ATP-driven active sliding.

Adenosine Triphosphate↗
PubMed1993

Induction of topoisomerase I-mediated DNA cleavage by a new indolocarbazole, ED-110.

ED-110 is a new semisynthetic antitumor agent derived from a novel indolocarbazole antibiotic, BE-13793C, produced by an actinomycete. ED-110 induced topoisomerase I-mediated DNA cleavage in vitro as strongly as camptothecin, whereas topoisomerase II-mediated DNA cleavage was not induced by this agent. Exposure of P388 cells to ED-110 caused a typical topoisomerase toxicity, i.e.: formation of cleavable complexes; inhibition of nucleotide synthesis rather than protein synthesis; and cell cycle arrest in G2. ED-110 inhibited the growth of P388 cells, with a 50% growth-inhibitory concentration of 44 nM. ED-110 is distinguished from camptothecin by its very different structure and its ability to intercalate into double-stranded DNA. These results suggest that ED-110 has potential as a novel antitumor agent targeting topoisomerase I.

Animals↗
PubMed1993

Immunohistochemical detection of prostaglandin I2 synthase in various calcified tissue-forming cells in rat.

Localization of prostaglandin (PG) I2 synthase immunoreactivity was examined in demineralized sections of rat pulpal, periodontal and skeletal tissues using isn-1, a monoclonal antibody raised against the enzyme. Various calcified tissue-forming cells, i.e. odontoblasts, osteoblasts, osteocytes, cementoblasts, cementocytes and chondrocytes, were similarly immunoreactive for PGI2 synthase, suggesting that they are capable of producing PGI2. In odontoblasts and chondrocytes, the reactivity increased gradually with maturation. Weak immunoreactivity was also observed in endothelial cells and fibroblast-like cells in pulpal and periodontal tissues. However, no reactivity was seen in ameloblasts. These results suggest the possible involvement of PGI2 in the regulation of the metabolism of various calcified tissues. Monoclonal antibodies such as isn-1 may become useful markers of the maturation of calcified tissue-forming cells of mesenchymal origin.

Animals↗