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Biomedical subjects

M Kubota

Publications and source records attributed to M Kubota.

At least 37 records · Page 2Linked to original sources
PubMed2003

Micro X-ray computed tomography analysis for the evaluation of asymmetrical condylar growth in the rat.

OBJECTIVES: To investigate the influence of forced lateral bite on mandibular growth, micro X-ray computed tomography (CT) was used for the purpose evaluating condylar cartilage and cancellous bone formation in 10 male Wister rats (3 weeks of age). SETTINGS AND SAMPLE POPULATION: The rats were divided into two groups--experimental and control. In experimental group, an inclined crown was cemented onto the maxillary incisors to produce 2.5 mm shift toward the left side during mastication. Right-left differences in whole mandibular length, mandibular height, condylar size, trabecular structure of the condylar head and three-dimensional (3-D) finite element analysis were assessed using 3-D images reconstructed from micro X-ray CT scans when the mice had reached 21 weeks. MEASUREMENTS AND RESULTS: Asymmetrical growth was found in the experimental group, in which the left condylar head became thicker and shorter than the right condylar head during development. When comparing the left and right condyles of the experimental animals, histomorphometric analysis from micro X-ray CT showed that the bone volume (BV) of the cancellous bone, the surface area of the cancellous bone (BS), the BS/BV ratio, the BV fraction (BV/TV), and the trabecular thickness and trabecular number were less for the right condyle than for the left condyle. CONCLUSIONS: These findings suggested that artificial changes in the mastication do influence the growth of condylar head, condylar bone trabecular structure, and mineralization.

Animals↗
PubMed2002

Heavily T2 weighted MR images of anterior optic pathways in patients with sellar and parasellar tumours - prediction of surgical anatomy.

OBJECTIVE: Location of anterior optic pathways in sellar and parasellar tumours was preoperatively evaluated, by use of heavily T2 weighted MR images. METHODS: Heavily T2 and conventional T1 weighted images were studied in 20 patients with sellar and parasellar tumours who underwent craniotomy. Pathology revealed pituitary adenoma in 5 patients, craniopharyngioma in 8 and parasellar meningioma in 7. Maximum sizes ranged from 15 mm to 58 mm. Sequence parameters of TR/TE for heavily T2 weighted and T1 weighted images were 5800/220 msec and 600/20 msec, respectively, and slice thickness was 3 mm for both. RESULTS: The anterior optic pathway was detected in 95% on heavily T2 weighted images and 50% on T1 weighted images. All preoperative heavily T2 weighted images were compatible with operative findings. The optic chiasms were most commonly supero-posterior in pituitary adenomas, anterior (prefixed) in craniopharyngiomas and posterior in meningiomas. The optic nerves were commonly located superior or lateral to the tumours. However, parasellar meningiomas, off the midline, revealed the optic nerves in various locations, depending on the tumour origin. In such tumours, heavily T2 weighted images provided surgical information on the width of the working space through prechiasmal and/or optico-carotid spaces in the pterional approach. Spatial relation of the tumours to the lamina terminalis, anterior commissure and anterior communicating artery complex was clearly shown in craniopharyngioma patients, who underwent the anterior interhemispheric approach. CONCLUSION: Heavily T2 weighted MR images are useful in determining the location of optic pathways and surgical approach and in individual prediction of the anatomy for even large sellar and parasellar tumours.

Adenoma↗
PubMed2002

A case of retropharyngeal abscess caused by penicillin-resistant Streptococcus pneumoniae.

We report here a case of a 1-year-old girl with retropharyngeal abscess caused by penicillin-resistant Streptococcus pneumoniae (PRSP). Computed tomography disclosed a retropharyngeal mass lesion (4 cm x 3 cm in diameter), and the diagnosis was confirmed by needle aspiration of the retropharyngeal space, which yielded PRSP. To our knowledge, this is the first report of a young subject in whom retropharyngeal abscess was caused by this organism. Retropharyngeal abscess is most common in children younger than 3 or 4 years of age, during which period a high carriage rate of PRSP is also shown. This patient was successfully treated with panipenem/betamipron.

Abscess↗
PubMed2001

Structure of human holocarboxylase synthetase gene and mutation spectrum of holocarboxylase synthetase deficiency.

Holocarboxylase synthetase (HLCS) is an enzyme that catalyzes the incorporation of biotin into apo-carboxylases, and its deficiency causes biotin-responsive multiple carboxylase deficiency. The reported sequences of cDNA for human HLCS from liver, lymphocyte, and KG-1 myeloid cell lines differ at their 5' regions. To elucidate variations of the human HLCS mRNA and longer 5' cDNA ends, we performed screening of the human liver cDNA library and rapid amplification of the cDNA ends (RACE). Our results suggest the existence of three types of HLCS mRNA that start at different exons. The first type starts at exon 1, and the second type starts at exon 3, and both are found in various human tissues. The third type, corresponding to the cDNA from the KG-1 cell, starts at exon 2 of the HLCS gene. Various splicing patterns from exons 3-6 were also observed. None of the variations of cDNA found created a new initiation codon. Mutation screening from exons 6-14, therefore, was sufficient to detect amino acid changes in HLCS in patients. Our direct sequencing strategy for screening mutations in the HLCS gene revealed mutations in five Japanese patients and seven non-Japanese patients. Our analyses involving 12 Japanese and 13 non-Japanese patients and studies by others indicate that (1) there is no panethnically prevalent mutation; (2) the Arg508Trp, Gly581Ser, and Val550Met mutations are found in both Japanese and non-Japanese populations; (3) the IVS10+5G-->A mutation is predominant and probably a founder mutation in European patients; (4) the 655-656insA, Leu237Pro, and 780delG mutations are unique in Japanese patients; (5) the spectrum of the mutations in the HLCS gene may vary substantially among different ethnic groups.

Base Sequence↗
PubMed2001

Rewarming eliminates the protective effect of cooling against delayed neuronal death.

Mild intra-ischemic hypothermia provides neuroprotection against delayed neuronal death in the hippocampal CA1. It has recently been reported that reduction in the metabolic rate of arachidonic acid (AA) liberated during ischemia might contribute to this neuroprotection. To examine whether rewarming during the early period of recirculation accelerates AA consumption and eliminates the neuroprotection, we measured the levels of AA in the hippocampus after various recirculation times under normothermia and hypothermia with or without rewarming. The tendency for AA to disappear was significantly different between each pair of groups. Histological examination 7 days after ischemia revealed no protection in the rewarmed group. These results suggest that neuronal injury during rewarming after hypothermia may be attributed to the rate of AA metabolism.

Animals↗
PubMed2001

Regional distribution of ethanolamine plasmalogen in the hippocampal CA1 and CA3 regions and cerebral cortex of the gerbil.

Although ethanolamine plasmalogens (EtnPm) are the predominant phospholipids in neural tissue, their physiological role has not been clarified. The biophysical conformation of EtnPm in the proteoliposome enhances the activity of the sodium-calcium exchanger, which has been proposed to induce intracellular calcium ion accumulation during ischemia and early reperfusion. The levels of EtnPm in the areas of the gerbil brain selectively vulnerable to ischemia, namely the hippocampal CA1 and CA3 regions and the cerebral cortex, were measured by high-performance thin-layer chromatography and gas-liquid chromatography. The concentration of EtnPm in the CA1 region, which is the most vulnerable to ischemic and anoxic stress, was 2.6- and 2.7-fold higher than that in the CA3 region and cerebral cortex, respectively. The significantly higher concentration of EtnPm in the hippocampal CA1 region may enhance sodium-calcium exchanger activity and play an important role in the vulnerability of this region to ischemia.

Animals↗
PubMed2001

Intact LTP and fear memory but impaired spatial memory in mice lacking Ca(v)2.3 (alpha(IE)) channel.

To investigate the functional roles of the Ca(v)2.3 (alpha(1E)) channel in hippocampal CA1 pyramidal neurons, we studied in vitro synaptic properties and in vivo behaviors of the Ca(v)2.3 gene deficient mice. The Ca(v)2.3 channel mRNA was identified in the hippocampal formation of the wild-type mouse by in situ hybridization. The basic excitatory synaptic transmission and long-term potentiation by theta-burst stimulation were intact in CA1 region of Ca(v)2.3-/- mice. We performed two forms of behavioral tests to examine the hippocampus-dependent function, i.e., emotional and spatial learning tests. The Ca(v)2.3-/- mice were able to establish and maintain fear memories. Although general improvement in the performance of Morris water maze test was seen in Ca(v)2.3-/- mice, they displayed an obvious impairment in the probe test. These results suggest that the Ca(v)2.3 channel plays some role in formation of the accurate spatial memory but not of the fear memory.

Animals↗
PubMed2001

Unusual presentation of measles giant cell pneumonia in a patient with acquired immunodeficiency syndrome.

The typical clinical presentation of measles in a normal immunocompetent host includes cough, coryza, conjunctivitis, Koplik's spots, and rash. However, in an immunocompromised host, measles may have an atypical clinical presentation and may be commonly associated with severe pneumonia or encephalitis. We report a fatal case of measles pneumonia without any clinical features that suggest measles in a patient with acquired immunodeficiency syndrome.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Infiltration of cervical lymph nodes by B- and T-cell non-Hodgkin's lymphoma and Hodgkin's lymphoma: preliminary ultrasonic findings.

Ultrasonography has been used in the evaluation of enlarged lymph nodes in patients with malignant lymphoma, which comprises a variety of histopathological subtypes. We assessed ultrasonic findings of infiltration in cervical lymph nodes of 47 patients with previously untreated malignant lymphoma and correlated them with histopathological subtypes. Common findings among various histopathological subtypes were hypoechoic masses, spot and/or line echoes, involvement of multiple nodes, and posterior enhancement. In addition, each histopathological subtype showed characteristic findings: Hodgkin's disease had a contour with a lobular pattern (9/10 cases), septum-like echo (9/10 cases), and tubular structure (9/10 cases) in the internal echo, reflecting histopathologically fibrous connective tissue surrounding lymph nodes and small vessels. In B-cell lymphoma, there was characteristically a tendency for lymph node fusion (19/28 cases) and spot and/or line echoes (17/28 cases), reflecting histopathological replacement and destruction of the structure of lymph node and capsule by proliferation of lymphocytes. These findings were strengthened in diffuse large B-cell lymphoma. T-cell lymphoma was distinguished from other types of lymphoma by the presence of a hilum-like echo (6/9 cases), reflecting histopathologically prominent vascularization in lymph nodes accompanied by a dilated hilum area. In summary, this preliminary study suggests that ultrasonic findings of infiltration of cervical lymph nodes in major subtypes of malignant lymphoma could reflect characteristic histopathological structures, therefore providing information helpful for differentiating them.

Adult↗
PubMed2001

Clinical development of trastuzumab in breast cancer.

The HER-2/neu protein is thought to be a unique and useful target for antibody therapy of cancers overexpressing the HER-2/neu gene. The recombinant humanized anti-HER-2 monoclonal antibody, trastuzumab (Herceptin) is now available for clinical use in the U.S.A. It is also expected to be available in Japan in the near future. In this paper, the details of this novel biologic agent are reviewed in conjunction with a phase I study performed in Japan.

Animals↗
PubMed2001

Compassionate use of humanized anti-HER2/neu protein, trastuzumab for metastatic breast cancer in Japan.

The HER-2/neu protein is thought to be a unique and useful target for antibody therapy of cancers overexpressing the HER-2/neu gene. The recombinant humanized anti-HER-2 monoclonal antibody, trastuzumab (Herceptin) was approved for clinical use in the US in 1998. In Japan, it was approved and later became available in June, 2001. We have treated 41 patients with metastatic breast cancer with trastuzumab purchased from the US. In this paper, the details of the patients we experienced are reviewed.

Adult↗
PubMed2001

Repetitious appearance and disappearance of different kinds of clonal cytogenetic abnormalities after allogeneic bone marrow transplantation.

We report a childhood case that showed the repeated appearance and disappearance of various kinds of cytogenetic abnormalities (CA) for 5.5 years after allogeneic bone marrow transplantation (BMT). The patient underwent allogeneic BMT from an HLA-matched unrelated donor during the second complete remission of acute lymphoblastic leukemia. The conditioning regimen for BMT consisted of etoposide, cyclophosphamide, anti-human thymocyte immunoglobulin, and total body irradiation. There were no leukemic relapses or secondary acute myeloid leukemia/myelodysplastic syndrome (AML/MDS) since the BMT. The CA occurred from residual recipient cells, which were damaged by chemotherapy or radiation prior to BMT. Although previous studies about post-BMT CA had reported the continuous emergence of identical clones, the present case showed the appearance of one different type of clone after another. Although the appearance of different types of CA may mean that these clones did not obtain any growth advantages, it may be a sign of genomic instability, which is probably a risk factor for the development of secondary AML/MDS.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Optimum treatment strategy for superficial esophageal cancer: endoscopic mucosal resection versus radical esophagectomy.

This study was designed to determine the optimum treatment for a superficial esophageal cancer involving the mucosal or submucosal layer of the esophagus. The subjects were 150 patients with a superficial esophageal cancer who underwent endoscopic mucosal resection (EMR) or esophagectomy in Kurume University Hospital from 1981 to 1997. The mortality and morbidity rates, survival rate, and recurrence rate were retrospectively compared for (1) 35 patients who underwent EMR and 37 patients who underwent esophagectomy for a mucosal esophageal cancer and (2) 45 patients who underwent extended radical esophagectomy and 33 patients who underwent less radical esophagectomy for a submucosal esophageal cancer. Among the 72 patients with a mucosal cancer, lymph node metastasis/recurrence was observed in only one (1%); whereas of 78 patients with a submucosal cancer it was observed in 30 (38%). Among patients with a mucosal cancer the mortality and morbidity rates after EMR were lower than for those after esophagectomy. The survival rate after EMR was the same as that after esophagectomy. No recurrence was observed after either treatment modality. Among the patients with a submucosal cancer, the survival rate was higher and the recurrence rate lower after extended radical esophagectomy; than after less radical esophagectomy; the mortality and morbidity rates after extended radical esophagectomy were the same as those after less radical esophagectomy. Multivariate analysis demonstrated that the treatment modality (EMR versus esophagectomy) did not influence the survival of patients with a mucosal esophageal cancer, whereas it strongly influenced the survival of patients with a submucosal esophageal cancer. We concluded that EMR was the mainstay of treatment for a mucosal esophageal cancer, and extended radical esophagectomy was the mainstay of treatment for a submucosal esophageal cancer.

Aged↗
PubMed2001

Funnel chest: treatment strategy and follow-up.

Although funnel chest is the most frequently seen deformity of the anterior chest wall in children, there is still considerable controversy regarding three major aspects, namely, the frequency of such deformities, their physiological importance, and the methods available for treatment. We retrospectively analyzed our experience with the 154 patients managed in our department. In 81 of these an operation was performed (OP), and the clinical findings for this group were compared with the 73 patients in whom an operation was not performed (NOP). Evaluation included subjective findings, especially the views of the patients' parents, and objective findings, including chest radiographs, computed tomography (CT), spirogram, electrocardiography, and echocardiography. In all patients the assessment included postoperative respiratory symptoms, appearance of the chest, and psychological aspects related to the deformity. Post-operatively, respiratory symptoms almost invariably subsided. The cosmetic result could initially be regarded as satisfactory or fair during the first 10 years following surgery, but over time there was frequently increasing concern regarding the scar. The NOP patients showed significantly less severity of the funnel index compared with OP patients. However, there was no spontaneous improvement in the deformity in older patients; most of the NOP patients continued to show a cosmetic deformity and 26.7% had psychological problems. This retrospective study confirms that our treatment strategy of objective criteria for operation (functional compression index > 0.2, % vital capacity <80, and CT index less than 0.25) and timing of operation (between 4 and 6 years of age) provides good results. Based on the analysis of long-term follow-up, surgery is considered indicated in patients with severe deformity. However, in the interest of psychological development, the indications for surgery may be extended.

Abnormalities, Multiple↗
PubMed2001

Heavily T2 weighted MR assessment of fornical injury after anterior interhemispheric approach for large suprasellar tumors.

Fornical injury in transforaminal approach is well known. Its injury in the anterior interhemispheric approach (AIA) has been rarely highlighted. We report 2 cases with a large suprasellar tumor who underwent AIA. Postoperative heavily T2 weighted reversed (T2R) MR images demonstrated its unilateral injury. The clinical significance of symptom-free fornical injury after AIA is discussed. Cases 1 and 2 were a 15 year-old girl with a meningioma and a 49-year-old woman with a craniopharyngioma, respectively. They underwent AIA. Postoperative T2R images revealed unilateral fornical crus atrophy. They did not present associated memory deficits. Case 1 had the injury of both fornical column and anterior commissure. They were speculatively torn by intra-operative lateral retraction of the frontal lobes. Case 2 had unilateral atrophy of the mammillary body and postcommissural fornix, which were probably caused by ischemic damage related to surgical manipulation, since case 2 had an associated anterior thalamic infarct. During the operation for large suprasellar tumors, excessive laterally directed brain retraction should be avoided, since such manipulation may easily tear the overstretched anterior commissure and fornical column. Once we notice or suspect fornical injury on MR studies in cases of re-operation, we have to choose a surgical approach and operative manipulation to preserve an intact fornix. The MR evaluation of fornix should be included in the perioperative radiological assessment, since patients with unilateral fornical injury were free of memory disturbance, and T2R imaging is a useful MR sequence for depicting the anatomy related to the fornix.

Adolescent↗
PubMed2001

Influences of venous involvement on postoperative brain damage following the anterior interhemispheric approach.

BACKGROUND: The anterior interhemispheric approach offers us an excellent surgical view for suprasellar lesions. Following this approach, we occasionally encounter postoperative brain damage in the frontal lobes. To assess the determinants of such a complication, we undertook a clinical study. METHOD: Potential causes for such brain damage were evaluated in 28 consecutive patients with suprasellar tumours extirpated using this approach. We focused particularly on the influences of venous involvement during surgery. The draining territory index (DTI) was originally devised for estimating the extent of the draining area of the sacrificed bridging veins. FINDINGS: CT evident brain damage was observed in five of 28 patients (17.8%), but only one patient (3.6%) showed clinically significant postoperative deficits. The patient's age, tumour pathology, tumour character, tumour size, duration of surgery, and radicality of the surgery did not affect the incidence of the brain damage. Of the twelve patients whose bridging veins were sacrificed during surgery, four (33.3%) showed brain damage in the frontal lobes. In contrast, such damage was observed in only one patient out of 16 (6.3%) whose bridging veins were preserved. Among the brain-damaged group, the average DTI of the sacrificed veins was significantly higher than that among the non-brain-damaged group. INTERPRETATION: Venous involvement during surgery significantly aggravated postoperative brain damage following the anterior interhemispheric approach. The DTI was useful in predicting the risk of brain damage, and a large bridging vein with a DTI over 50% should not be sacrificed during surgery.

Adult↗