Biomedical subjects

Naoki Kato

Publications and source records attributed to Naoki Kato.

At least 19 recordsLinked to original sources

PubMed2007

[A case of infected subdural hematoma].

A 87-year old male was admitted to our hospital due to generalized convulsion with loss of consiousness. He was afebrile and his blood sampling was not infectious. Computed tomography scan suspected left chronic subdural hematoma. Burr hole drainage was performed to remove the hematoma, but the abscess was aspirated in the subdural space. Infected subdural hematoma is rare. We discuss the clinical presentation, diagnosis and. treatment, and also briefly review the literature.

Aged, 80 and over↗

PubMed2006

Biosynthesis of malonylated flavonoid glycosides on the basis of malonyltransferase activity in the petals of Clitoria ternatea.

The crude malonyltransferase from the petals of Clitoria ternatea was characterized enzymatically to investigate its role on the biosynthetic pathways of anthocyanins and flavonol glycosides. In C. ternatea, a blue flower cultivars (DB) and mauve flower variety (WM) accumulate polyacylated anthocyanins (ternatins) and delphinidin 3-O-(6''-O-malonyl)-beta-glucoside which is one of the precursors of ternatins, respectively. Moreover, WM accumulates minor delphinidin glycosides - 3-O-beta-glucoside, 3-O-(2''-O-alpha-rhamnosyl)-beta-glucoside, 3-O-(2''-O-alpha-rhamnosyl-6''-O-malonyl)-beta-glucoside of delphinidin. These glycosidic patterns for minor anthocyanins in WM are also found among the minor flavonol glycosides in all the varieties including a white flower variety (WW) although the major flavonol glycosides are 3-O-(2''-O-alpha-rhamnosyl)-beta-glucoside, 3-O-(6''-O-alpha-rhamnosyl)-beta-glucoside, 3-O-(2'',6''-di-O-alpha-rhamnosyl)-beta-glucoside of kaempferol, quercetin, and myricetin. How do the enzymatic characteristics affect the variety of glycosidic patterns in the flavonoid glycoside biosynthesis among these varieties? While the enzyme from DB highly preferred delphinidin 3-O-beta-glucoside in the presence of malonyl-CoA, it also has a preference for other anthocyanidin 3-O-beta-glucosides. It could use flavonol 3-O-beta-glucosides in much lower specific activities than anthocyanins; however, it could not utilize 3-O-(2''-O-alpha-rhamnosyl)-beta-glucosides of anthocyanins and flavonols, and 3,3'-di- and 3,3',5'-tri-O-beta-glucoside of delphinidin - other possible precursors in ternatins biosynthesis. It highly preferred malonyl-CoA as an acyl donor in the presence of delphinidin 3-O-beta-glucoside. The crude enzymes prepared from WM and WW had the same enzymatic characteristics. These results suggested that 3-O-(2''-O-alpha-rhamnosyl-6''-O-malonyl)-beta-glucosides of flavonoids were synthesized via 3-O-(6''-O-malonyl)-beta-glucosides rather than via 3-O-(2''-O-alpha-rhamnosyl)-beta-glucosides, and that malonylation proceeded prior to glucosylation at the B-ring of delphinidin in the early biosynthetic steps towards ternatins. It seemed that the substrate specificities largely affected the difference in the accumulated amount of malonylated glycosides between anthocyanins and flavonols although they are not simply proportional to the accumulation ratio. This enzyme might join in the production of both malonylanthocyanins and flavonol malonylglycosides as a result of broad substrate specificities towards flavonoid 3-O-beta-glucosides.

Acyltransferases↗

PubMed2006

Peripheral nerve palsies associated with closed fractures and dislocations.

We have studied 178 consecutive cases of 203 patients admitted to this unit between 1999 and 2003 with diagnosis of peripheral nerve palsies associated with closed fractures and dislocations in the upper and lower limbs. Fifty-one nerves were explored, 25 of which were found partly or completely transected. Indications for surgery were high-energy transfer injury, severe neuropathic pain, failure to progress and a static Tinel's sign. Spontaneous recovery was good in only 25 of the 51 non-operated cases of high-energy transfer injury to the circumflex, radial and common peroneal nerves. Good spontaneous recovery is closely related to low-energy transfer injury, and is associated with an advancing Tinel's sign. Absence of the Tinel's sign indicates conduction block; neurophysiological investigation confirms it. We stress the particular value of the Tinel's sign, and note that severe neuropathic pain indicates continuing damage to the nerve and gives a strong reason for operation.

Adolescent↗

PubMed2006

[Trends in the incidence of stroke in Yamagata, Japan].

The purpose of this study was to clarify the incidence and features of acute cerebrovascular diseases in Yamagata Prefecture, by comparing with those in other prefectures reported in previous studies. Consecutive 13,639 cases of acute stroke were prospectively registered to Yamagata Society in Treatment for Cerebral Stroke (YSTCS) between January 1, 1998 and December 31, 2002. Cerebral infarction (CI), intracerebral hemorrhage (CH), subarachnoid hemorrhage (SAH) and transient ischemic attack (TIA) were observed in 58.4%, 25.8%, 11.4% and 4.4% of the patients, respectively. The frequencies of CH and SAH (37.2%) in Yamagata Prefecture were higher than those reported in other studies (p < 0.01). In addition, time from onset to admission in Yamagata Prefecture was longer than that reported in others(p< 0.01). This study was one of the largest stroke registration studies in Japan enrolling 13,639 patients. In addition, computed tomography (CT) and/or magnetic resonance image (MRI) was performed on admission in all patients. Diagnosis was made by a neurologist or a neurosurgeon based on CT and/or MRI findings. Our results might accurately reflect current status of stroke patients in Yamagata Prefecture.

Adult↗

PubMed2005

Sequential changes of nitric oxide levels in the temporal lobes of kainic acid-treated mice following application of nitric oxide synthase inhibitors and phenobarbital.

Although studies have indicated a close relationship between nitric oxide (NO) and kainic acid (KA)-induced seizures, the role of NO in seizures is not fully understood. Here, we quantified NO levels in the brain of KA-treated mice using EPR spectrometry to elucidate the role of NO in KA-induced seizures. KA was administered to mice with or without pretreatment with one of the following: N(G)-nitro-l-arginine methyl ester (l-NAME), an NO synthase (NOS) inhibitor that acts on both endothelial NOS (eNOS) and neuronal NOS (nNOS); 7-nitroindazole (7-NI), which acts more selectively on nNOS in vivo; or the anti-epileptic drug, phenobarbital. To accurately assess NO production during seizure activity, we directly measured KA-induced NO levels in the temporal lobe using an electron paramagnetic resonance NO trapping technique. Our results revealed that the both dose- and time-dependent changes of NO levels in the temporal lobe of KA-treated mice were closely related to the development of seizure activity. l-NAME mediated suppression of the KA-induced NO generation led to enhanced severity of KA-induced seizures. In contrast, 7-NI induced only about 50% suppression and had little effect on seizure severity; while phenobarbital markedly reduced both NO production and seizure severity. These results show that KA-induced neuroexcitation leads to profound increases in NO release to the temporal lobe of KA-treated mice and that NO generation from eNOS exerts an anti-convulsant effect.

Animals↗

PubMed2005

Nonviral HVJ (hemagglutinating virus of Japan) liposome-mediated retrograde gene transfer of human hepatocyte growth factor into rat nervous system promotes functional and histological recovery of the crushed nerve.

Hepatocyte growth factor (HGF) is well known to be involved in many biological functions, such as organ regeneration and angiogenesis, and to exert neurotrophic effects on motor, sensory, and parasympathetic neurons. In this study, we gave repeated intramuscular injections of the human HGF gene, using nonviral HVJ (hemagglutinating virus of Japan) liposome method, to examine whether transfection of the rat nervous system with this gene is able to exert neurotrophic effects facilitating recovery of a crushed nerve. The expression of HGF protein and HGF mRNA indicated that gene transfer into the nervous system did occur via retrograde axonal transport. At 4 weeks after crush, electrophysiological examination of the crushed nerve showed a significantly shorter mean latency and a significantly greater mean maximum M-wave amplitude with repeated injections of HGF gene. Furthermore, histological findings showed that the mean diameter of the axons, the axon number and the axon population were significantly larger in the group with repeated injections of HGF gene. The above results show that repeated human HGF gene transfer into the rat nervous system is able to promote crushed-nerve recovery, both electrophysiologically and histologically, and suggest that HGF gene transfer has potential for the treatment of crushed nerve.

Analysis of Variance↗

PubMed2005

Interstitial magnetic resonance lymphography using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid in rabbits with lymph node metastasis.

RATIONALE AND OBJECTIVES: To investigate the dose dependency of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) for interstitial magnetic resonance (MR) lymphography and the detection of lymph node metastasis in rabbits. METHODS: Eighteen VX2 tumor-bearing rabbits were subjected to MR lymphography using clinical MRI equipment. The enhancement of popliteal lymph nodes was studied in these rabbits before and at 2.5 to 10 minutes after the subcutaneous administration of 4, 8, or 17 micromol Gd/kg of Gd-EOB-DTPA in TSE and 3D-FLASH (n = 6). Signal-to-noise ratio and contrast-to-noise ratio were statistically compared between each group by the Tukey test. After MR imaging, the popliteal lymph nodes were removed, and sections were prepared for microscopic examination. RESULTS: In the histologic findings, all metastases (3-12 mm) in the popliteal lymph nodes were detected by 3D-FLASH images. Gd-EOB-DTPA-enhanced T1WI showed a hypointense region for metastasis and a hyperintense region for nontumor regions, although the lymph nodes containing metastasis were detected as a hyperintense region by conventional PDWI and T2WI. Signal enhancement of the nontumor regions and contrast between the nontumor regions and metastasis showed dose dependency and reached a plateau at 8 micromol Gd/kg on T1WI (signal-to-noise ratio: 13.9 +/- 1.6; contrast-to-noise ratio: -12.7 +/- 1.7). CONCLUSIONS: This study showed that interstitial MR lymphography with Gd-EOB-DTPA can detect metastasis and that the optimal dose in rabbits is 8 micromol Gd/kg as a subcutaneous application.

Animals↗

PubMed2005

Potential of superparamagnetic iron oxide in the differential diagnosis of metastasis and inflammation in bone marrow: experimental study.

RATIONALE AND OBJECTIVES: The utility of ferucarbotran for the diagnosis of bone metastases was investigated using tumor-implanted rabbits. The potential of ferucarbotran in the differential diagnosis of metastasis and inflammation was also investigated. METHODS: Twelve rabbits were divided into 2 groups (tumor and inflammation groups). Six rabbits of tumor group were inoculated with VX2 tumor cell suspension, and the 6 rabbits of the inflammation group were inoculated with 10% croton oil in the bone marrow of the right femur. All rabbits were imaged using a clinical MRI system. Signal intensity in the bone marrow of the right femur was measured in each rabbit before and after the intravenous injection of 8 micromol Fe/kg of ferucarbotran. As a control, the signal intensity in the bone marrow of the left femur (the normal, intact femur) was measured in each rabbit. The change in signal intensity of each group was compared statistically. After MRI imaging, the femora were removed, and sections were prepared for microscopic examination. RESULTS: Signal intensity in the right femur of the tumor group did not change after injection, although that of the inflammation group and the control group decreased. In the histologic findings, tumors were widely spread in the right femur of the tumor group. The infiltration of pseudoeosinocytes was induced in the right femur of the inflammation group. CONCLUSIONS: This animal study showed that ferucarbotran was useful to detect bone marrow tumors. In addition, ferucarbotran may have potential in the differential diagnosis of bone metastasis and some kinds of inflammation.

Animals↗

PubMed2005

Nonviral gene transfer of human hepatocyte growth factor improves streptozotocin-induced diabetic neuropathy in rats.

Peripheral neuropathy is common and ultimately accounts for significant morbidity in diabetes. Recently, several neurotrophic factors have been used to prevent progression of diabetic neuropathy. In this study, we gave repeated intramuscular injections of the human hepatocyte growth factor (HGF) gene percutaneously, using liposomes containing the hemagglutinating virus of Japan (HVJ), to examine therapeutic efficacy of nonviral gene transfer of HGF for experimental diabetic sensorimotor neuropathy in rats. Experimental diabetes induced by intraperitoneal injection of streptozotocin resulted in a marked tactile allodynia (but not in a thermal hyperalgesia), in a reduction of both the conduction velocity and the amplitude, and in a decreased laser Doppler flux of the nerve and the muscle at 6 weeks after the induction. All these changes were significantly reversed by repeated gene transfer of HGF. Furthermore, we analyzed the density of endoneurial capillaries and morphometrical changes of the nerve. The density of endoneurial capillaries, disclosing marked reduction in diabetic rats, was also reversed significantly by repeated gene transfer of HGF; however, no considerable differences were observed morphometrically in either myelinated or unmyelinated axons. These results suggest that nonviral HVJ liposome-mediated gene transfer of human HGF has potential for the safe effective treatment of diabetic sensorimotor neuropathy.

Animals↗

PubMed2005

[Serum S-100B protein and neuron-specific enolase after traumatic brain injury].

OBJECTIVE: The aim of this study was to investigate S-100B protein and NSE as a serum marker of brain cell damage after traumatic brain injury. MATERIAL AND METHODS: Forty-one patients with traumatic brain injury were included in this prospective study. Venous blood samples for S-100B protein and NSE were taken after admission and on the next day. Serum levels of S-100 protein and NSE were compared with Glasgow Coma Scale score, computed tomographic findings and outcome after 3 months. RESULTS: Serum S-100B protein and NSE were significantly correlated with Glasgow Coma Scale score and outcome after 3 months. The significant correlation was found between the initial S-100B and NSE (P < 0.001). In patients without parenchymal injuries on computed tomographic scan such as epidural hematoma and concussion, the elevation of S-100B protein and NSE was observed. The initial values of S-100B and NSE in acute subdural hematomas with unfavorable outcome were significantly higher than in those with favorable outcome. Secondary increase of serum markers was associated with the presence of secondary insult such as hypoxia or hypotension, and was found to have an unfavorable outcome. CONCLUSIONS: Serum concentration and kinetics of S-100B protein and NSE provide the clinical assessment of the primary brain damage and have a predictive value for outcome after traumatic brain injury.

Analysis of Variance↗

PubMed2004

Identification of delphinidin 3-O-(6''-O-malonyl)-beta-glucoside-3'-O-beta-glucoside, a postulated intermediate in the biosynthesis of ternatin C5 in the blue petals of Clitoria ternatea (butterfly pea).

Ternatins are blue anthocyanins found in the petals of Clitoria ternata (butterfly pea). Among them, ternatin C5 (delphinidin 3-O-(6''-O-malonyl)-beta-glucoside-3',5'-di-O-beta-glucoside; 2) has the structure common to all the ternatins, which is characterized by its glucosylation pattern: a 3,3',5'-triglucosylated anthocyanidin. In the course of studying biosynthetic pathways of ternatins, the key enzymatic activities to produce ternatin C5 were discovered in a crude enzyme preparation from the petals of a blue petal line of C. ternatea. When this preparation was tested for activity against several delphinidin glycosides, delphinidin 3-O-(6''-O-malonyl)-beta-glucoside-3'-O-beta-glucoside (6), a postulated intermediate, was found in the reaction mixture, together with three known anthocyanins, which were spectroscopically structurally identified. As a result of structural identification, the following enzymatic activities were identified: UDP-glucose :delphinidin 3-O-(6''-O-malonyl)-beta-glucoside-3'-O-beta-glucoside 5'-O-glucosyltransferase (5'GT), UDP-glucose :delphinidin 3-O-(6''-O-malonyl)-beta-glucoside 3'-O-glucosyltransferase (3'GT), UDP-glucose :delphinidin 3-O-glucosyltransferase, and malonyl-CoA :delphinidin 3-O-beta-glucoside 6''-malonyltransferase. In a mauve petal line, which did not accumulate ternatins but delphinidin 3-O-(6''-O-malonyl)-beta-glucoside in its petal, there were neither 5'GT nor 3'GT activities. Thus, the early biosynthetic pathway of ternatins may be characterized by the stepwise transfer of two glucose residues to 3'- and 5'-position of delphinidin 3-O-(6''-O-malonyl)-beta-glucoside (1; Scheme) from UDP-glucose.

Anthocyanins↗

PubMed2004

Enterovirus-related type 1 diabetes mellitus and antibodies to glutamic acid decarboxylase in Japan.

OBJECTIVES: In order to clarify the relationship between enteroviruses and type 1 diabetes mellitus in Japan we investigated enteroviral RNA in serum from children with type 1 diabetes mellitus. METHODS: We investigated enteroviral RNA in serum from children with type 1 diabetes mellitus by using highly sensitive RT-PCR. Additionally the sequences and viral loads were determined and compared with anti-coxsackie virus antibodies and anti-glutamic acid decarboxylase (GAD) antibodies. RESULTS: RT-PCR for enterovirus was positive in 23 (37.7%) from 61 samples. The positivity had no disparity of age, but decreased by aging after the occurrence of type 1 diabetes mellitus. The sequences of the positives were similar as those of coxsackie B4. The viral loads revealed that there was no positive patient with high titers of anti-GAD antibodies. CONCLUSION: In Japan there is some correlation with type 1 diabetes mellitus and enterovirus. The pathophysiology of type 1 diabetes mellitus seems to consist of a direct destruction by persistent coxsackie virus and the autoimmune mechanism through autoantibodies against beta-cells.

Adolescent↗

PubMed2004

The effect of hyperbaric oxygen therapy on the bout of treatment for soft tissue infections.

OBJECTIVES: Hyperbaric oxygen (HBO) therapy is often combined with antibiotic therapy for infections such as gas gangrene and osteomyelitis. Although numerous investigations have been undertaken to assess the effect of adjunctive HBO therapy on the treatment of infections, the bout of treatment has not been referred in the previous investigations. The purpose of this retrospective study was to evaluate the efficacy of HBO therapy on the bout of treatment for soft tissue infections. PATIENTS AND METHODS: In the period between 1994 and 2001, we treated 23 patients with soft tissue infections. Nine patients were treated with antibiotic chemotherapy alone, and 14 patients were treated with a combination of antibiotic chemotherapy and HBO therapy. The mean bout of treatment was compared between these two groups. RESULTS: The mean bout treated with a combination of antibiotic and HBO was significantly shorter than that with antibiotic alone. CONCLUSION: Our result indicates that HBO therapy combined with antibiotic therapy is able to shorten the bout of treatment for soft tissue infections. Therefore, we recommend HBO therapy combined with antibiotic therapy for soft tissue infections.

Adult↗

PubMed2004

Potential for differential diagnosis with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging in experimental hepatic tumors.

RATIONALE AND OBJECTIVES: To investigate whether dynamic and delayed magnetic resonance imaging (MRI) with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA), a hepatobiliary MRI contrast agent, has potential for the differential diagnosis of experimental hepatic tumors. METHODS: Twelve male rats received N-nitrosomorpholine solution as drinking water to induce hepatic tumors. After injection of Gd-EOB-DTPA, rats were subjected to dynamic and delayed MRI. The relative enhancement (RE) was calculated, and the time of the maximum RE (Tmax) was evaluated. After MRI, liver was histologically analyzed. RESULTS: One hundred sixty-three hepatic tumors 3-12 mm in diameter were induced after 18 weeks of treatment with 0.01 wt/vol% of N-nitrosomorpholine, and 81 of them were evaluated. The RE in hyperplastic nodules (HPNs) was significantly higher than that in moderately or poorly differentiated hepatocellular carcinomas (HCCs) in the late phase, whereas there was no significant difference in RE between well-differentiated HCCs and HPNs. The average Tmax in HPNs was about 13 minutes, whereas that of each differentiated HCCs was about 1 minute. CONCLUSIONS: It was possible to differentiate benign HPNs and malignant HCCs (especially well-differentiated HCCs) by evaluating the change of RE or comparison of Tmax with Gd-EOB-DTPA-enhanced MRI.

Animals↗

PubMed2004

[An outbreak of diarrheal disease caused by enterotoxigenic Clostridium perfringens following exposure to a contaminated environment in a nursing home].

We herein report an outbreak of non-food-borne diarrhea which occurred in a nursing home due to enterotoxigenic Clostridium perfringens. The regional public health center in Gifu, Japan, recognized 7 patients with diarrhea in a nursing home, suspecting a food-borne illness. Bacteriological and epidemiological studies indicated that enterotoxigenic C. perfringens was the causative agent. However, suspected foods, the kitchen and the cooks carried no enteropathogenic bacteria, indicating that this outbreak was a non-food-borne diarrhea. The swab specimens obtained from the residential area of the nursing home were found to have enterotoxigenic C. perfringens. Isolates from the stool specimens of patients and environment were all serotype TW47, showing susceptibilities to ampicillin, levofloxacin, and clindamycin very similar to each other, and had banding patterns identical to each other by pulsed-field gel electrophoresis. These results strongly supported the existence of monoclonal spread of an enterotoxigenic C. perfringens among the environment of the nursing home and the residents. During 3 weeks 14 residents were involved in this outbreak. The extensive effort of keeping the residential area clean led to a prompt cease of this outbreak.

Aged↗

PubMed2003

Influence of peripheral inflammation on growth-associated phosphoprotein (GAP-43) expression in dorsal root ganglia and on nerve recovery after crush injury.

An experimental study was performed to investigate the influence of the inflammation in peripheral target tissue on growth-associated phosphoprotein (GAP-43) expression in dorsal root ganglia (DRG) and on recovery of crushed nerve. Fifty-four male Wistar rats were used for this study. The sciatic nerve was operatively crushed unilaterally with an aneurysm clip. Inflammation in peripheral target tissue was induced by injection of complete Freund's adjuvant (CFA) at 1 week before crush. In crushed or crushed with arthritis rats DRGs were examined in immunohistochemistry for GAP-43 and the sciatic nerves were observed in Epon embedded sections with toluidine blue stain. In addition, electrophysiological studies of the nerves were performed to evaluate the recovery of function. Immunohistochemical studies showed the ratio of GAP-43 immunopositive cells in crushed with arthritis rats was significantly lower than that in crushed rats at 1 week after crush (P<0.01). Electrophysiological studies at 4 weeks after crush showed functional nerve recovery in crushed with arthritis rats was significantly suppressed compared with that in crushed rats (P<0.01). Histological studies showed the mean diameter of the axons in crushed with arthritis rats was significantly smaller than that in crushed rats (P<0.01). All these findings indicate that inflammation in peripheral target tissue suppresses GAP-43 expression in DRG and eventually suppresses functional and morphological recovery of the crushed nerve.

Animals↗

PubMed2003

Efficient gene transfer from innervated muscle into rat peripheral and central nervous systems using a non-viral haemagglutinating virus of Japan (HVJ)-liposome method.

We evaluated the feasibility of gene delivery into the peripheral and central nervous systems via retrograde axonal transport following injection of a haemagglutinating virus of Japan (HVJ)-liposome-DNA complex vector into an innervated muscle. Transfection efficiency was assessed by measuring luciferase activity, and was compared statistically with that achieved using a liposome-DNA control vector. High luciferase activity was observed in the injected muscle, the ipsilateral sciatic nerve, and the ipsilateral dorsal root ganglia on day 1 after gene transfer. The spinal cord also showed luciferase activity, although this was lower than in the other tissues. However, no activity was observed in the contralateral sciatic nerve or the contralateral dorsal root ganglia. In addition, we performed gene transfer twice, with a 1-week interval, to evaluate the feasibility of repeated therapeutic gene delivery. Again, a high transfection efficiency was observed immediately, even after the second gene transfer, and transfection efficiency was significantly higher at each defined time-point using the HVJ-liposome complex vector than using a control vector. These results indicate that this method could be used for repeated therapeutic gene delivery into muscle, nerve, dorsal root ganglia, and possibly spinal cord, without the need for a surgical approach, making it well suited to clinical applications.

Animals↗

PubMed2003

Primary repair of the collateral ligament of the proximal interphalangeal joint using a suture anchor.

Ten out of 12 complete ruptures of the collateral ligament of the proximal interphalangeal joint were repaired primarily using a suture anchor. Active finger exercise was started gently by taping the injured finger to adjacent one one week postoperatively. All patients returned to their original occupation or sports activities within seven weeks of operation. No patients complained of pain on the involved finger at rest or during movement. There was no instability of the proximal interphalangeal joint on manual lateral stress test postoperatively.

Adolescent↗