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Biomedical subjects

H Nakata

Publications and source records attributed to H Nakata.

At least 55 records · Page 3Linked to original sources
PubMed2000

Acute aortic thrombosis after intra-aortic balloon pumping.

Acute aortic occlusion is a rare but devastating complication of intra-aortic balloon pumping. Prompt diagnosis of aortic occlusion and immediate therapeutic decision making are keys for saving patients in such cases. We describe a 72-year-old man who underwent emergency surgical removal of a thrombus and aortoiliac bifurcated grafting for acute aortic occlusion after withdrawal of the intra-aortic balloon pumping catheter. The presence of a small unrecognized abdominal aortic aneurysm was considered to be the cause of thrombosis in this patient. Ultrasonographic screening for an abdominal aortic aneurysm is recommended for patients who require intra-aortic balloon pumping support.

Acute Disease↗
PubMed2000

Minimally invasive direct coronary artery bypass grafting in a patient with brainstem infarction.

Brainstem infarction associated with the primitive trigeminal artery is rare. We describe the case of a 61-year-old man with an acute myocardial infarction as well as a brainstem infarction. The patient was referred for coronary artery bypass grafting. Minimally invasive direct coronary artery bypass grafting (left internal thoracic artery to the second diagonal branch anastomosis) could be safely performed 10 weeks after an episode of brainstem infarction.

Brain Stem↗
PubMed2000

Isomer-specific accumulation and toxic assessment of polychlorinated biphenyls, including coplanar congeners, in cetaceans from the North Pacific and Asian coastal waters.

To elucidate the global distribution and toxicological impacts of polychlorinated biphenyls (PCBs) on cetaceans, the present study determined the concentrations of individual PCB congeners, including toxic non-ortho (IUPAC Nos. 77, 126, 169) and mono-ortho (IUPAC Nos. 105, 118, 156) coplanar congeners, in the blubber of 10 species of adult male odontocetes collected from several locations in the North Pacific Ocean and along coastal waters of Japan, Hong Kong, the Philippines, and India during 1985-1997. Total PCB concentrations in cetaceans from temperate and cold waters were higher than those in cetaceans from tropical regions. Residue levels were found to be the highest in Fraser's dolphins collected off Kii Peninsula, Japan, and hump-backed dolphins from Hong Kong, reflecting serious marine pollution by PCBs in industrialized Asian countries. Penta- and hexa-chlorobiphenyls were the predominant PCB congeners, accounting for about 70% of the total PCBs. 2,3,7,8-Tetrachlorodibenzo-p-dioxin equivalents (TEQs) of non- and mono-ortho coplanar PCBs in the blubber of cetaceans ranged from 36 (in spinner dolphins from the Philippines) to 510 pg/g wet weight (in hump-backed dolphins from Hong Kong). Toxic evaluation of coplanar PCBs using the TEQ concept indicates an greater impact on cetaceans from mid-latitudes. Toxicity contribution of mono-ortho congener IUPAC 118 was prominent in species from high latitude oceans, such as the Bering Sea and the North Pacific, whereas non-ortho congener IUPAC 126 accounted for the highest contribution in cetaceans from lower latitude regions, such as the Philippines and India. The estimated TEQ concentrations in the blubber of some cetacean species, such as northern right whale dolphin and Pacific white-sided dolphin from the northern North Pacific, Dall's porpoise from the Japan Sea, striped dolphin off Sanriku and Fraser's dolphin off Kii Peninsula, Japan, hump-backed dolphin and finless porpoise from Hong Kong, exceeded the levels associated with immunosuppression in harbour seals.

Animals↗
PubMed2000

Mediastinal myelolipoma: CT and MRI appearances.

A 72-year-old man presented with a mediastinal mass on chest radiograph. Computed tomography and MR imaging showed that the mass consisted of both fatty and small nodular soft tissue components, highly suggestive of an extramedullary hematopoiesis or a myelolipoma. A CT-guided needle biopsy was next performed and confirmed the diagnosis. We discuss the CT and MR imaging appearances es of this tumor and usefulness of a CT-guided needle biopsy to avoid surgery in asymptomatic patients.

Aged↗
PubMed2000

Formation of the male-specific muscle in female Drosophila by ectopic fruitless expression.

The Drosophila fruitless (fru) gene product Fru has been postulated to be a neural sex-determination factor that directs the development of at least two male-specific characteristics, namely courtship behaviour and formation of the muscle of Lawrence (MOL). The fru gene encodes a putative transcription factor with a BTB domain and two zinc-finger motifs, and with consensus Tra-binding sequences. The binding of Tra to these sequences results in sex-specific alternative splicing of the fru mRNA, leading to production of the 'male-type' or 'female-type' Fru protein. We show here that the Fru protein is not detected in the female central nervous system (CNS), despite the similar level of expression of fru mRNA in both male and female CNS. As ectopic expression of both the 'male-type' (with the sequence for the amino-terminal extension) and 'female-type' (without the sequence for the amino-terminal extension) fru cDNA can induce formation of the MOL in females, the presence or absence of the Fru protein, and not its sex-specific structure, seems to be responsible for the sexually dimorphic actions of the fru gene.

Alleles↗
PubMed2000

Effectiveness of spray application of ACNU in the local control of malignant gliomas: report of two cases.

Malignant gliomas encompassing the eloquent areas cannot be removed totally and their surgical extirpation is followed by adjuvant therapy for the residual tumor. Recently, we have employed fibrin glue as a vehicle for the sustained release of ACNU (nimustine hydrochloride) by spray application following subtotal tumor removal in two patients with recurrent malignant gliomas. Follow-up MRI at six months demonstrated no neuroradiological evidence of tumor recurrence in the site of operation. We conclude, this novel mode of intra-operative local chemotherapy by spray application of fibrin glue containing antineoplastic agent is effective in the control of residual tumor progression and may also prevent local recurrence and hence suggests its possible role as an adjuvant therapy in the management of malignant gliomas.

Aerosols↗
PubMed2000

Cyclic nucleotide-gated channels colocalize with adenylyl cyclase in regions of restricted cAMP diffusion.

Cyclic AMP is a ubiquitous second messenger that coordinates diverse cellular functions. Current methods for measuring cAMP lack both temporal and spatial resolution, leading to the pervasive notion that, unlike Ca(2+), cAMP signals are simple and contain little information. Here we show the development of adenovirus-expressed cyclic nucleotide-gated channels as sensors for cAMP. Homomultimeric channels composed of the olfactory alpha subunit responded rapidly to jumps in cAMP concentration, and their cAMP sensitivity was measured to calibrate the sensor for intracellular measurements. We used these channels to detect cAMP, produced by either heterologously expressed or endogenous adenylyl cyclase, in both single cells and cell populations. After forskolin stimulation, the endogenous adenylyl cyclase in C6-2B glioma cells produced high concentrations of cAMP near the channels, yet the global cAMP concentration remained low. We found that rapid exchange of the bulk cytoplasm in whole-cell patch clamp experiments did not prevent the buildup of significant levels of cAMP near the channels in human embryonic kidney 293 (HEK-293) cells expressing an exogenous adenylyl cyclase. These results can be explained quantitatively by a cell compartment model in which cyclic nucleotide-gated channels colocalize with adenylyl cyclase in microdomains, and diffusion of cAMP between these domains and the bulk cytosol is significantly hindered. In agreement with the model, we measured a slow rate of cAMP diffusion from the whole-cell patch pipette to the channels (90% exchange in 194 s, compared with 22-56 s for substances that monitor exchange with the cytosol). Without a microdomain and restricted diffusional access to the cytosol, we are unable to account for all of the results. It is worth noting that in models of unrestricted diffusion, even in extreme proximity to adenylyl cyclase, cAMP does not reach high enough concentrations to substantially activate PKA or cyclic nucleotide-gated channels, unless the entire cell fills with cAMP. Thus, the microdomains should facilitate rapid and efficient activation of both PKA and cyclic nucleotide-gated channels, and allow for local feedback control of adenylyl cyclase. Localized cAMP signals should also facilitate the differential regulation of cellular targets.

Adenoviridae↗
PubMed2000

Synthesis and structure-activity relationships of selective ligands for P3 purinoceptor-like protein (P3LP).

We examined the structure-activity relationship of various 5'-N-substituted-carboxamidoadenosine derivatives toward P3 purinoceptor-like protein (P3LP), which has affinity for both adenine nucleosides and nucleotides. We discovered a hydrophobic binding region near the 5'-N-substituted-carboxamide group. From the linear alkyl N-substituted derivatives, 1-(adenin-9-yl)-1-deoxy-N-n-pentyl-beta-D-ribofuranuronamide (6) was found to be the most potent ligand. In the series of the N-cycloalkyl derivatives, 1-(adenin-9-yl)-1-deoxy-N-cyclohexyl-beta-D-ribofuranuronamide (8) was the strongest ligand. We also examined the receptor selectivity for the selected nucleosides 6 and 8 with 1 (HAK2701) and N-ethylcarboxamidoadenosine (NECA) versus P1 purinoceptor subtypes, such as adenosine A1, A2A, A2B, and A3 receptors and found 8 is the most selective ligand for P3LP.

Adenosine↗
PubMed2000

Scalp marking for a craniotomy using a laser pointer during preoperative computed tomographic imaging: technical note.

OBJECTIVE: The preoperative localization of superficial intracranial lesions is often necessary for accurate burr hole placement or craniotomy siting. It is not always easy, however, to localize the lesions over the scalp working only from computed tomographic images. We developed a simple method for such localization using a laser pointer during the preoperative computed tomographic examination. METHODS: The angle of incidence, extending from a point on the scalp to the center of the computed tomographic image, is measured by the software included with the scanner. In the gantry, at the same angle as on the image, a laser is beamed from a handmade projector onto the patient's scalp toward the center of the gantry. The point illuminated on the patient's head corresponds to that on the image. The device and the method are described in detail herein. RESULTS: We applied this technique to mark the area for the craniotomy before surgery in five patients with superficial brain tumors. At the time of surgery, it was confirmed that the tumors were circumscribed precisely. CONCLUSION: The technique is easy to perform and useful in the preoperative planning for a craniotomy. In addition, the device is easily constructed and inexpensive.

Brain Neoplasms↗
PubMed2000

Regulation of granulocyte colony-stimulating factor and parathyroid hormone-related protein production in lung carcinoma cell line OKa-C-1.

Previously we have established a clonal squamous cell carcinoma cell line OKa-C-1 derived from lung cancer of a patient with marked leukocytosis and hypercalcemia. OKa-C-1 cells simultaneously produce granulocyte colony-stimulating factor (G-CSF) and parathyroid hormone-related protein (PTHrP) at the single cell level and cause paraneoplastic syndromes in nude mice bearing the tumor. It is known that the production of G-CSF and PTHrP is individually regulated by inflammatory cytokines in various malignant cells. To investigate the common factors in the regulation of G-CSF and PTHrP production in OKa-C-1 cells, we examined the effects of some inflammatory agents [lipopolysaccharide (LPS), phorbol-12-myristate-13-acetate (PMA), tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1) beta and IL-6] on G-CSF and PTHrP production, by means of enzyme-linked immunosorbent assay (ELISA), immunoradiometric assay (IRMA) and quantitative reverse transcription-polymerase chain reaction (RT-PCR). TNF-alpha or IL-1beta induced both G-CSF and PTHrP production in the conditioned medium. TNF-alpha synergized with IL-1beta to significantly increase G-CSF production. In addition, TNF-alpha and IL-1beta strongly induced G-CSF mRNA with peaks at 2 and 6 h respectively. Although PTHrP production was also strongly induced by TNF-a PTHrP mRNA expression was more strongly induced by PMA than by TNF-alpha. Thus, TNF-alpha and IL-1beta could be common factors that individually and synergistically regulate G-CSF and PTHrP production in OKa-C-1 cells. Moreover, G-CSF and PTHrP production could be not only transcriptionally, but also posttranscriptionally regulated by other factors.

Animals↗
PubMed2000

Spontaneous coughing up of a polyp.

We report the case of an 18-year old female with right lower lobe atelectasis, who was admitted to our hospital because of a nonproductive cough. She underwent fiberoptic bronchoscopy that revealed a peduncular polyp in the right truncus intermedius or middle bronchus. Before admission for laser polypectomy, she spontaneously coughed up the tissue mass, and the right lower lobe atelectasis disappeared. We report a rare case of 'autopolypectomy' of a bronchial adenoma.

Adenoma↗
PubMed2000

Auto-induction of E5110 metabolism, a novel non-steroidal anti-inflammatory drug, during toxicokinetic studies in beagle dogs.

Following single-dose intravenous and oral studies to determine the absolute bioavailability of E5110 in beagle dogs, repeated dose pharmacokinetic studies were conducted as toxicokinetics in a subacute toxicity test. E5110 was administered orally once a day for 91 days at doses of 0, 1, 10, 50 and 250 mg/kg/day to dogs. On the first day during repeated administration, the Cmax and AUC values of E5110 in females were lower than those for males, and it seems that this may be due to a sex-related difference in the activity of cytochrome P450 (CYP) 3A. During repeated administration of E5110, the plasma levels of E5110 on day 15 and day 91 were markedly lower than those on the first day. On day 91, the AUCs for E5110 were 55.9%, 38.8%, 10.9% and 7.8% in males, and 76.2%, 80.3%, 10.5% and 11.9% in females on the first day, for doses of 1, 10, 50 and 250 mg/kg/day, respectively. Liver microsomes prepared after the last dose of E5110 showed increased activities of benzphetamine N-demethylase, p-nitroanisole O-demethylase, and aminopyrine N-demethylase, at doses of 1 mg/kg/day or more. A dose-dependent increase in P450 content was also observed. Furthermore, the capacity for 5-hydroxylate E5110 was increased, and Western blot analysis indicated an induction of CYP2B and 3A; therefore CYP3A may contribute to a main metabolic pathway of E5110. These results suggested that the decrease in plasma concentrations of E5110 that were observed during repeated administration represents a typical case of auto-induction of the phenobarbital type.

Animals↗
PubMed2000

Evolution of peripheral lung adenocarcinomas: CT findings correlated with histology and tumor doubling time.

OBJECTIVE: This study was performed to evaluate the evolution of peripheral lung adenocarcinomas using CT findings and histologic classification related to tumor doubling time. MATERIALS AND METHODS: The subjects were 34 patients, each with an adenocarcinoma smaller than 3 cm. All patients underwent chest radiography and 10 of them had previously undergone CT more than 6 months before surgery. Tumor doubling time was estimated by examining sequential radiographs using the method originally described by Schwartz. Tumor growth was also observed by studying the changes on CT in the 10 patients who had previously undergone CT. The histologic classification (types A-F) was evaluated according to the criteria of Noguchi et al. RESULTS: Five (83%) of the six adenocarcinomas with tumor types A or B showed localized ground-glass opacity on high-resolution CT. All six tumors had a tumor doubling time of more than 1 year. Fifteen (71%) of the 21 tumors with type C showed partial ground-glass opacity mixed with localized solid attenuation on high-resolution CT. Ten (48%) of these 21 type C tumors had a tumor doubling time of more than 1 year. In types B and C, the solid component or the development of pleural indentation and vascular convergence increased during observation before surgery. All seven tumors with types D, E, and F showed mostly solid attenuation, and the tumor doubling time was less than 1 year in six (87%) of the seven tumors. CONCLUSION: Two main types of peripheral lung adenocarcinoma exist. The first type appears on CT as a localized ground-glass opacity with slow growth, and the other appears as a solid attenuation with rapid growth.

Adenocarcinoma↗
PubMed2000

[Usefulness of temporal subtraction images of chest computed radiography for detection of metastatic pulmonary nodules].

Temporal subtraction is a technique by which a previous chest radiograph is subtracted from a current radiograph in order to enhance interval changes. Our purpose in this study was to evaluate the usefulness of temporal subtraction for the detection of metastatic pulmonary nodules. We examined 19 cases of metastatic nodules less than 15 mm in diameter (8.4 mm on average). Temporal subtraction images were created based on the matching of local lung areas in pairs of chest radiographs. By using the subtraction images, the detectability of nodules was clearly improved in 5 cases and moderately improved in 8 cases; there was no improvement in 6 cases. The subtraction images were especially useful for nodules superimposed over normal structures, such as rib, mediastinum, and diaphragm, as well as for small nodules. In 6 of the 19 cases, the nodules had been missed clinically; however, the temporal subtraction images clearly demonstrated half of missed small nodules. Temporal subtraction made it possible to enhance subtle interval changes and helped in detecting small pulmonary metastases. This technique seems promising for augmenting the capabilities of computed radiography of the chest.

Adult↗
PubMed2000

[Diagnosis--radiologic imaging].

One of the most important recent advances in imaging technology for the diagnosis of lung cancer is CT consisting of high-resolution and helical volumetric techniques. CT has made a detailed morphological analysis correlated with histopathology as well as the detection of small peripheral lung cancers possible. MRI still remains as a complementary role to CT, but MR angiography using fast gradient-echo technique has achieved a great progress. FDG-PET is the most encouraging development in nuclear medicine and is vigorously evaluated for its cost-effective clinical value in differentiating benign and malignant nodules as well as in staging of lung cancer. In chest radiography, the development of computer-aided diagnosis is underway and seems promising.

Humans↗
PubMed2000

Isolation of Pseudomonas aeruginosa from Ushubetsu River water in Hokkaido, Japan.

To provide information on the ecology of Pseudomonas aeruginosa in nature, bacteriological surveillance was performed in the defined area in Hokkaido, Japan. P. aeruginosa was isolated from water samples of Ushubetsu River in the down stream from the urban area of Asahikawa. P. aeruginosa was isolated from fecal samples of pigs but not from samples of soil of a tomato field, sand of sandboxes in vest-pocket parks, fresh vegetables, or feces of wild deer. The present results indicate that P. aeruginosa strains isolated from the river water is originated from the environment of human activity and not from wild life or domestic animals.

Animals↗
PubMed2000

[A case of ruptured aneurysm in a patient over 90 years of age, successfully treated by clipping with the use of a one-way ball valve for cisternal drainage].

The authors report a case of ruptured aneurysm in a patient in her 90's who was treated by clipping and returned to her independent life after discharge. A 91-year-old woman with a diagnosis of SAH of Hunt & Kosnik Grade III was treated using a conventional clipping operation with cisternal drainage. The cisternal drainage was assembled as a closed system using a newly developed one-way ball valve to regulate the CSF outflow. With this system the patient was able to take any posture and do any movement she wished, not being obligned to stay in bed. Early postoperative rehabilitation was able to be started to prevent pneumonia and muscular atrophy. The drainage was stopped on the 27th postoperative day when the CSF became clear. During the period of drainage, neither valve obstruction nor meningitis was noted. This valve system allows patients under cisternal drainage to move freely. It would be useful, especially when dealing with the elderly, to prevent unwanted complications often caused by postoperative restraint imposed by confinement to bed.

Aged↗