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Biomedical subjects

K Araki

Publications and source records attributed to K Araki.

At least 127 records · Page 7Linked to original sources
PubMed1998

Rotavirus encephalitis mimicking afebrile benign convulsions in infants.

A 2-year-old-boy had rotavirus gastroenteritis and demonstrated afebrile partial seizures with secondary generalization. The presence of rotavirus genome and anti-rotavirus IgG was detected in the cerebrospinal fluid. The genotype of VP4 was P8 and that of VP7 was G4. The imaging analysis by computed tomography and single photon emission computed tomography implied encephalitis. The seizures were well controlled by standard antiepileptic therapy, and the child experienced normal development with neither physical nor neurologic sequelae, which appeared to mimic benign infantile partial epilepsy.

Child, Preschool↗
PubMed1998

Region-specific expression of murine Hox genes implies the Hox code-mediated patterning of the digestive tract.

BACKGROUND: Hox genes encode transcription factors which are involved in the establishment of regional identities along the anteroposterior (AP) body axis. To elucidate the AP patterning of the digestive tract, we have systematically examined the expression patterns of Hox genes belonging to paralogue groups 6, 7, 8 and 9 by whole-mount in situ hybridization and by section in situ hybridization analyses. RESULTS: The expression patterns of these genes showed co-linearity along the wall of the digestive tract, thereby yielding the Hox code of the gut. The expression boundaries of the Hox genes at later stages (12.5 d.p.c.) corresponded to the morphological boundaries of individual gut subdomains. CONCLUSIONS: The visceral mesoderm-restricted expression suggested that the Hox code primarily functions in the mesenchymal specification which eventually leads to the regional differentiation of gut subdomains as the result of epithelial-mesenchymal interactions. Overlapping expression patterns were found among the paralogous Hox genes, indicating that the paralogues may have redundant functions in the specification of the gut.

Animals↗
PubMed1998

In vitro performance of a centrifugal, a mixed flow, and an axial flow blood pump.

We specially devised 3 types of turbo pumps, a centrifugal pump (CFP), a mixed flow pump (MFP), and an axial flow pump (AFP), and analyzed their in vitro performance. The common structural design elements were an impeller diameter of 20 mm and sealless magnet couple driving. In vitro tests were carried out using heparinized fresh bovine blood. The hemolysis was comprehensively evaluated at 7-16 points by changing the flow rate and pressure head (mapping of hemolytic property). The maximum efficiency (motor output to pump output) was 44.9% at 7,000 rpm, 3.17 L/min, 191 mm Hg in the CFP; 66.3% at 7,000 rpm, 6.9 L/min, 136 mm Hg in the MFP; and 20.6% at 9,000 rpm, 5.54 L/min, 74 mm Hg in the AFP, respectively. The minimum normalized index of hemolysis (NIH) (g/100 L) was 0.038 at 5,000 rpm, 4.60 L/min, 38 mm Hg in the CFP; 0.010 at 7,000 rpm, 8.22 L/min, 100 mm Hg in the MFP; and 0.033 at 7,000 rpm, 2.84 L/min, 48 mm Hg in the AFP, respectively. The best efficiency and NIH were achieved in the MFP.

Animals↗
PubMed1998

The nature of psychiatric problems among disaster victims.

One-quarter of the residents (about 52,000) in the disaster area around the volcanic eruption area of Mt Unzen-Fugen have been forced to evacuate over a 3 year period. We conducted a psychological controlled study using the GHQ-30 for evacuees. As a result, the percentage of people with a high score over 8 points was 67% of evacuees, markedly higher than 10% of the control group. Some mental support activities, such as counseling by community nurses and crisis intervention/medication by psychiatrists and others, have been promoted. Subjects who received a psychiatric intervention had good outcome as a whole. The nature of psychiatric problems among disaster evacuees and the necessity of long-term support are discussed in this paper.

Adolescent↗
PubMed1998

[Prevalence of human astrovirus serotypes in Shizuoka 1991-96].

A latex agglutination test (LA) for astrovirus types 1-4 detection and typing was used on rotavirus- and adenovirus-negative stool samples from children with diarrhea between 1991 and 1996. Of the 478 samples tested, 30 were identified as astrovirus-positive. Most of the patients with astrovirus infections were under 2 years old. Astrovirus type 1 was the most prevalent serotype; 20/30 (66.7%), followed by type 4 (16.7%), type 3 (13.3%), and type 2 (3.3%). A prevalence of astrovirus-associated diarrhea was observed between January and June each year.

Adolescent↗
PubMed1998

[Analysis of transmission of Burkholderia cepacia isolates in an intrahospital by randomly amplified polymorphic DNA-PCR method].

Strains of Burkholderia cepacia isolated in our hospital from November 1995 to September 1996 were classified with randomly amplified polymorphic DNA-PCR (RAPD-PCR) and conventional biochemical tests (ID test.NF-18, API20NE, and Neg Combo 4J kit), and intrahospital isolates of B. cepacia were analysed. During the period 28 strains from inpatients and 2 from medical apparatus were isolated. Twenty four of 28 (85.7%) were from sputum. In 1996 from January to February, 20 strains were detected from 8 inpatients, and two strains were from the nebulizers at the Trauma and Critical Care Center (TCC). With typing of B. cepacia by conventional methods no epidemiological relations among isolates were found. However, DNA patterns of original isolates from the nebulizers at TCC by RAPD-PCR were identical with those of isolates in sputa from patients in other wards who had stayed at TCC, indicating that TCC was an initial source of transmission and the strain was transmitted with the patients to the wards. These results suggest that RAPD-PCR method might be a useful tool to analyse an epidemiological survey for intrahospital transmission of isolate.

Burkholderia Infections↗
PubMed1998

Eosinophilic proliferative pylephlebitis in the liver of Japanese beef cattle with fascioliasis.

Intrahepatic pylephlebitis was detected in 17 Japanese beef cattle. Grossly, the intrahepatic vessels in the caudate lobe and/or in the periphery of the other hepatic lobes were thickened and protruded above the lobar surface. The vessel lumina were packed with white to red, waste thread-like contents. A few immature flukes were found in the bile ducts in 3 of the 7 cases with biliary thickening. Foci of hepatic necrosis and hemorrhage were scattered around the thickened vessels in 8 cases. Histologically, the interlobular veins were thickened due to severe intimal hyperplasia with endothelial proliferation and eosinophilic accumulation and medial hypertrophy, accompanied by fibrosis and eosinophilic infiltration in the portal areas. Hepatic tissues with necrosis and hemorrhage were surrounded by eosinophils and histiocytes including a granulomatous reaction. One immature fluke was detected in one of these regions of necrosis. Immunoperoxidase staining revealed that the small fluke, Kupffer cells, and histiocytes in the liver of all cases were positively stained with anti-Japanese Fasciola sp. antiserum. Enzyme-linked immunosorbent assay of the sera of 15 cases revealed that all were positive for the anti-Fasciola antibody. On the basis of these findings, the present cases were regarded as an atypical form of fascioliasis, characterized by eosinophilic proliferative pylephlebitis of the liver.

Animals↗
PubMed1998

An electron microscopic study of Helicobacter pylori in the surface mucous gel layer.

This study describes the distribution of spiral and coccoid forms of Helicobacter (H.) pylori within the surface mucous gel layer (SMGL) on human gastric mucosae. Gastric mucosae infected with H. pylori were obtained from surgically removed stomachs of 14 cases of gastric cancer. The glycocalyx of the spiral and coccoid forms of H. pylori was examined for specific lectin labeling. Coccoid forms were identified in 11 of these cases (78.6%). The SMGL, which was from 50 to 100 microns in thickness, contained H. pylori throughout its entire thickness. Variously-sized vacuole-like clear areas were present near H. pylori. The glycocalyx on both the spiral and coccoid forms was similar in its staining with the 8 types of lectins tested. However, the staining pattern of the lectins varied among different samples. The numerous fibrillae-like filaments radiated from the surface of the bacteria and appeared to link the bacteria to the surface mucous cells or the surrounding mucus. These fibrillae-like filaments were not specifically stained by the lectin reactions, suggesting absence of sugar molecules.

Adult↗
PubMed1998

Indications for peripartum aortic pressure monitoring in Takayasu's disease. A patient with past history of intrapartum cerebral hemorrhage.

We describe a successful delivery by prophylactic cesarean section in a patient with Takayasu's disease who had a previous history of intrapartum cerebral hemorrhage during vaginal delivery. Aortography showed occlusion of the common carotid, subclavian and vertebral arteries on the left side, severe narrowing of the right subclavian artery, and moderate narrowing of the entire abdominal aorta. Blood pressure was managed by monitoring central aortic pressure at the thoracic aorta. During the peripartum course, we recommend monitoring the central aortic pressure in patients with Takayasu's disease in whom accurate blood pressure readings can not be obtained in any extremity.

Adult↗
PubMed1998

Localization of cytoskeletal filaments during membrane rearrangement in rat parietal cells stimulated with gastrin.

When stomachs are stimulated to secrete acid, the intracellular canaliculi of the parietal cell increase and there is a concomitant depletion of the cytoplasmic tubulovesicular system. This change is believed to occur through the transformation of tubulovesicular membranes into intracellular canaliculi. This study was undertaken to examine the distribution of the cytoskeletons in rat gastric parietal cells during this process. In the resting parietal cells, actin filaments decorated with heavy meromyosin (HMM) were found in the cores of microvilli, extending from the apex of microvilli into the pericanalicular cytoplasm and forming radial networks. In some cases, these actin filaments were also associated with the tubulovesicles. Moreover, tubulovesicular membranes were rare in the 300 nm zone around intracellular canaliculi but numerous actin filaments were seen in this region. Soon after stimulation of the parietal cells by gastrin, tubulovesicles were closely associated with the intracellular canaliculi, while actin filaments networks adjacent to the canaliculi diminished and their labeling with HMM seemed less orderly. By immunocytochemistry, immunogold particles indicating ezrin were associated with microvillous membranes in the resting as well as stimulated parietal cells but were absent on the tubulovesicular membranes. When intermediate filaments were immunocytochemically investigated using anti-cytokeratin immunogold particles clearly labeled filamentous bundles present around the intracellular canaliculi, perinuclear spaces and under the basolateral cell membrane. Their localization was not changed after stimulation. These results suggest that actin filaments in the cytoplasm around the intracellular canaliculi may play a key role in the translocation of the tubulovesicles toward the intracellular canaliculi during the acid secreting process.

Actins↗
PubMed1998

[Intraoperative local infusion chemotherapy (ILIC) for gastric cancer].

In order to provide a high dose of cis-diammine dichloro platinum (CDDP) into the regional lymph nodes and surrounding organs during operation, "intraoperative local infusion chemotherapy (ILIC)" was devised and has been applied to advanced gastric cancer patients. The aims of this method are 1) to reduce the possibility of metastasis by affecting the cancer cells before flowing out; 2) to administer drugs to the cancer cells which evade surgical resection; 3) to administer drugs to the lymphatic flow; and 4) to reduce the systemic side effects. After the laparotomy, the part of the stomach for gastrectomy was isolated from the blood supply, applying clamps to the proximal and distal parts of the stomach and hemostats to feeding blood vessels. Through a feeding artery to the tumor, 50 mg of CDDP was injected. Twenty-four patients underwent ILIC from June 1986 to December 1993. The 5-year survival rate was significantly better in the ILIC group compared to the control group which was selected by the matched pair method. The newly devised ILIC chemotherapy is a promising way to improve the prognosis of advanced gastric cancer patients. A randomized prospective study should be undertaken.

Animals↗
PubMed1998

Supramolecular cationic tetraruthenated porphyrin and light-induced decomposition of 2'-deoxyguanosine predominantly via a singlet oxygen-mediated mechanism.

The tetraruthenated porphyrin, mu-[meso-5,10,15,20-tetra(pyridyl)porphyrin]tetrakis[bis-(bipyridine) chloride ruthenium(II)] (TRP) is a supramolecular cationic species. The aim of the present investigation was to evaluate the photodynamic properties of TRP and Zn-TRP to damage DNA with emphasis on the mechanistic aspects. The ability for tetraruthenated porphyrin derivatives to induce photosensitization reactions has been determined using 2'-deoxyguanosine as a DNA model compound. The main photooxidation products of the targeted nucleoside were identified and classified according to their mechanisms of formation, involving either a radical pathway (type I) or a singlet oxygen-mediated mechanism (type II). Quantification of the different oxidation products provides a means to evaluate the relative contribution of type I and type II pathways associated with the oxidative photosensitization of 2'-deoxyguanosine by tetraruthenated porphyrin derivatives. Results indicate that 1O2 plays a major role in the mechanism of photooxidation mediated by these porphyrin derivatives. In addition an increase of the photosensitizing effect in the presence of zinc is observed. For each sensitizer, the ratio between type II and type I photoproducts has been calculated and compared to that of other known dyes such as methylene blue and riboflavin.

DNA Damage↗
PubMed1997

An early and massive wave of germinal cell apoptosis is required for the development of functional spermatogenesis.

Transgenic mice expressing high levels of the BclxL or Bcl2 proteins in the male germinal cells show a highly abnormal adult spermatogenesis accompanied by sterility. This appears to result from the prevention of an early and massive wave of apoptosis in the testis, which occurs among germinal cells during the first round of spermatogenesis. In contrast, sporadic apoptosis among spermatogonia, which occurs in normal adult testis, is not prevented in adult transgenic mice. The physiological early apoptotic wave in the testis is coincident, in timing and localization, with a temporary high expression of the apoptosis-promoting protein Bax, which disappears at sexual maturity. The critical role played by the intracellular balance, probably hormonally controlled, of the BclxL and Bax proteins (Bcl2 is apparently not expressed in normal mouse testis) in this early apoptotic wave is shown by the occurrence of a comparable testicular syndrome in mice defective in the bax gene. The apoptotic wave appears necessary for normal mature spermatogenesis to develop, probably because it maintains a critical cell number ratio between some germinal cell stages and Sertoli cells, whose normal functions and differentiation involve an elaborate network of communication.

Animals↗
PubMed1997

Mouse vaginal opening is an apoptosis-dependent process which can be prevented by the overexpression of Bcl2.

In the mouse, opening of the vaginal cavity to the skin is a late event, occurring around the fifth week of life; it can be induced in sexually immature mice by beta-estradiol injections. We have generated two lines of transgenic mice expressing the human Bcl2 protein in a variety of tissues. The vaginal cavity of the transgenic females remained permanently closed, a condition completely resistant to beta-estradiol injections; this was accompanied by a considerable distension of the genital tract. Histologic studies of vaginal sections at the time of opening to the skin in normal mice showed, by the TUNEL method which detects nuclei with fragmented DNA characteristic of apoptosis, that this event coincides with extensive apoptosis in the lower part of the vaginal mucosa, a process prevented in the bcl2 transgenic mice, which express Bcl2 in suprabasal epithelial cells and in subepithelial cells of the vaginal mucosa. In contrast, two lines of mice bearing a Bcl2 transgene placed under the control of a K10 keratin promoter, whose expression is restricted to the suprabasal layers of the epidermis, had a normal phenotype. Eyelids' formation and opening of the external ear canals, which also occur after birth in the mouse, were not altered in any of these transgenic lines; histological study of eye and ear sections at the time of these events failed to detect apoptosis. In conclusion, the tissue remodeling required to complete maturation of the mouse female genital tract at the time of puberty is an hormonally triggered apoptosis-dependent process.

Animals↗
PubMed1997

Targeted integration of DNA using mutant lox sites in embryonic stem cells.

Site-directed DNA integration has been achieved by using a pair of mutant lox sites, a right element (RE) mutant lox site and a left element (LE) mutant lox site [Albertet al. (1995)Plant J., 7, 649-659], in mouse embryonic stem (ES) cells. We established ES cell lines carrying a single copy of the wild-type lox Por LE mutant lox site as a target and examined the frequency of site-specific integration of a targeting vector carrying a loxP or RE mutant lox site induced by Cre transient expression. Since our targeting vector contains a complete neo gene, random integrants can form colonies as in the case of a gene targeting event through homologous recombination. With our system, the frequency of site-specific integration via the mutant lox sites reached a maximum of 16%. In contrast, the wild-type loxP sites yielded very low frequencies (<0.5%) of site-specific integration events. This mutatedloxsystem will be useful for 'knock-in' integration of DNA in ES cells.

Animals↗
PubMed1997

Ultra-high-resolution scanning electron microscopy of the sarcoplasmic reticulum of the rat atrial myocardial cells.

BACKGROUND: The sarcoplasmic reticulum (SR) of mammalian ventricular and atrial muscles share common features but also differ because T-tubules are rare and extended junctional SR is exclusively seen in the atrium. This scanning electron microscope (SEM) study was undertaken to clarify the three-dimensional organization of the rat atrial SR system. Specific preparations were examined with an ultra-high-resolution SEM. METHODS: Fixed right rat atria were frozen, fractured, and macerated by the aldehyde-osmium-DMSO-osmium method to remove myofibrils and cytoplasmic matrix. Left exposed were mitochondria, SR, and sarcolemma. Dried specimens were then impregnated by osmium-hydrazine and examined without metal coating. RESULTS: In place of conventional T-tubules, a prominent type of sarcotubules, Z-tubules, were found at the Z-line level. Branches from these tubules joined the cisternal SR, which was 100-300 nm in diameter and localized near the Z-line, and formed extensive SR meshworks and polygonal patches. Bulbous swellings, the corbular SR, were also evident. Sarcotubular reticulum completely surrounded each myofibril. The intermyofibrillar SR, especially Z-tubules, joined the peripheral subsarcolemmal SR, which was also arranged as a meshwork and was closely apposed to the sarcolemma. CONCLUSIONS: These SEM observations confirm the organization of the rat atrial SR system and present new, detailed, three-dimensional images of Z-tubules, cisternal SR, extended junctional SR, and peripheral SR, which provide further structural insight.

Animals↗