Biomedical subjects
Publications and source records attributed to E Yoshikawa.
The antibiotic susceptibilities of 43 strains of Escherichia coli O157:H7 identified in the summer of 1996 in Japan were investigated. Growth of 90% of O157 strains was inhibited at a concentration of < or = 0.5 micro/ml by several agents including fosfomycin with glucose-6-phosphate.
OBJECTIVE: To evaluate the relevance of hypometabolism in the hippocampal head to the pathophysiology of memory impairment. BACKGROUND: Neurofunctional imaging studies with an image reslicing technique provided by using software suggest that dysfunction of the amygdalohippocampal system causes memory impairment. However, metabolic and morphologic profiles of the whole hippocampal formation have not been evaluated in detail. METHODS: By tilting the gantry of a high-resolution PET scanner in a plane parallel to the hippocampal longitudinal axis determined beforehand by MRI, we performed quantitative measurement of glucose metabolism in the subdivisions of the hippocampal formation (head, body, tail) in 10 patients of normal intelligence with pure amnesia, in eight patients with AD, and in eight normal subjects. RESULTS: Although the volumes of the amygdala and hippocampal formation in pure amnesics were not different significantly from those of normal subjects, glucose metabolism in the head of the hippocampus was significantly lower in pure amnesics. In patients with AD, marked hypometabolism was found extending to the amygdala, the hippocampal head, and the parietotemporal cortex, along with amygdalohippocampal atrophy. CONCLUSION: Hippocampal head dysfunction plays an important role in memory impairment in amnesic patients. Further metabolic impairment over the amygdalohippocampal system and the surrounding association cortex reflects the pathophysiology of AD.
Among recent clinical isolates in Japan, strain CU264 was discovered which formed unusual colonies. This strain was identified as Rahnella aquatilis which is usually found in water. The antibiotic susceptibilities against tetracycline, carbenicillin, chloramphenicol, streptomycin, kanamycin, gentamicin, sulphonamide, neomycin, fosfomycin, rifampicin, norfloxacin and nalidixic acid, were investigated. The result demonstrated that the strain was highly resistant to fosfomycin only. It was further shown that this resistance was transmissible with low frequency to Serratia marcescens whereas it was not transmissible to Escherichia coli.
Positron emission tomography (PET) was used to measure changes in the regional cerebral blood flow (rCBF) of rhesus monkeys performing visual discrimination tasks. In comparison with both position and brightness discrimination tasks, the color discrimination task activated the posterior inferior temporal cortex and a ventromedial occipital region, which is located along the anterior one-third of the calcarine sulcus. In contrast, the position task activated the middle temporal area and intraparietal cortex as compared with the color task. These results confirm the segregation of visual pathways and delineate the visual areas involved in color vision. This approach might bridge the gap between invasive studies in animals and functional imaging studies in humans.
This study was designed to evaluate the ability of cementum-impregnated gelatine membranes (CGM) to stimulate regeneration of periodontal ligament following surgery. Three monkeys with no periodontal disease were used. Following flap elevation, recession type defects were created on the buccal side of maxillary lateral incisors and second premolars, and roots were subsequently planed. Experimental sites received CGM at approximately 2-3 mm below the cementoenamel junction while control sites received gelatine membrane (GM) free of cementum. Wounds were allowed to heal for 3 weeks, during which time daily plaque control measures were maintained. Tissues prepared from sacrificed animals revealed that experimental specimens exhibited formation of new cementum, new bone, and periodontal ligament. Control specimens exhibited connective tissue adhesion without either new cementum or significant new bone formation. Histometric analysis showed that the average vertical growth of cementum (NC) and bone (NB) at experimental sites were 3.48 +/- 0.29 and 0.64 +/- 0.43 mm, respectively. At the control sites the corresponding results were NC = 0.09 +/- 0.03 and NB = 0.06 +/- 0.28. It was concluded that placement of CGM resulted in significantly greater postsurgical cementum and bone formation than that of GM alone.
The purpose of this study was to investigate the initial healing response of surgically flapped periodontal tissues in the presence of gelatine membrane compounded with particles of cementum. Four monkeys with no periodontal disease were used in this experiment. Full thickness flaps were raised and recession type defects were created on the buccal side of the maxillary lateral incisors and second premolars. Exposed root surfaces were thoroughly curetted, and composite cementum-impregnated membranes placed directly onto planed root surfaces. Flaps were then sutured back to the original position. Animals were sacrificed at 2, 4, 7 and 10 post-surgical days, and block specimens including the tooth, gingiva and bone were subsequently processed for light and electron microscopy. The resultant analysis revealed that gelatine membranes were partially resorbed at 2 days post-surgery and completely resorbed by 10 postoperative days. In the early stages of gelatine resorption, most liberated cementum particles accumulated on planed dentin surface but some became demineralized within the surgical wound. Cementoblast-like cells with well-developed rough endoplasmic reticulum appeared on the root surface 7 days following surgery. Newly synthesized collagen fibrils aligned parallel to the root surface were seen at 10 post-surgical days. The results suggest that the newly developed composite membrane enhances the formation of new periodontal attachment.
A system for the measurement of brain activity in conscious monkeys by positron emission tomography (PET) was established in the present study. The signal/noise ratio was maximal around 40 s for data acquisition in the PET scan with 15O-labeled water. When the monkey was stimulated by vibration and subtraction images of the data sets from regional cerebral blood flow (rCBF) changes in paired stimulation and control were superimposed on magnetic resonance images obtained from the same specimens, a somatotopic map corresponding to the sites stimulated was clearly demonstrated. Visual stimulation with a photic stimulator activated the corresponding regions of the primary visual cortex. Comparison of the activated sites and extents under the conscious state with those under anesthesia assured that the study is controllable; there was little unpredictable activation due to unlimited subject movement or to psychological effects.
A case of fatal hematemesis due to an aberrant right subclavian artery-esophageal fistula is presented. The patient was a 9-year-old male child with complex congenital heart disease and developed the fistula by prolonged tracheal and nasogastric intubation after Fontan type operation. To avoid this unusual but serious complication, aberrant subclavian artery should be treated surgically before repair of complex cardiac anomaly.
Explore the source record for details and available documents.
Pretreatment for 3 days with oral ofloxacin or norfloxacin had no significant effect on the disposition of a single i.v. dose the theophylline in healthy volunteers.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.