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Biomedical subjects

K Kurisu

Publications and source records attributed to K Kurisu.

At least 109 records · Page 6Linked to original sources
PubMed1998

Trans-sellar color Doppler ultrasonography during transsphenoidal surgery.

OBJECTIVE: To improve the safety and efficacy of transsphenoidal pituitary adenoma surgery, we investigated transsphenoidal intraoperative color Doppler ultrasonography using a biplane transducer system. METHODS: We studied 23 patients with pituitary adenomas (18 patients with macroadenomas and 5 patients with microadenomas) who underwent transsphenoidal surgery. The Hitachi EUB555 color Doppler ultrasound system (Hitachi Medical, Tokyo, Japan) was used with a pediatric biplane transesophageal echo cardiography probe (EUP-ES533, 7.5 MHz, biplane phased array sector probe, 9.8-mm tip). The probe was inserted into the saline-filled sphenoid sinus after the sellar floor was opened. Intra- and suprasellar images were obtained just before dural incision and after the tumor removal was thought to have been accomplished. RESULTS: In all patients, the tumor was depicted as a slightly hyperechoic mass, as compared with the cerebrum. Using color Doppler imaging, major cerebral arteries were depicted clearly in 74% of patients. The pituitary glands, pituitary stalks, and optic chiasms were observed in patients with small adenomas, but not when large adenomas were present. Cavernous sinus invasion, concomitant aneurysm, and residual tumor were clearly visualized. In patients with large adenomas, the end point of surgery was decided when there was an ultrasonographically demonstrated collapsed tumor capsule, subcapsular total vacancy, and reappearance of the optic chiasm. CONCLUSION: Trans-sellar color Doppler ultrasonography seems to be a useful intraoperative guiding system that may improve the safety and efficacy of transsphenoidal surgery.

Adenoma↗
PubMed1998

Developmental role of PTHrP in murine molars.

Although PTHrP is produced in multiple fetal tissues, its precise physiological functions have yet to be clearly elucidated. The present study was undertaken to elucidate the biological role of PTHrP in the development of tooth. In rat tooth germs, the PTHrP and its receptor genes were expressed in the enamel organ and dental mesenchyme, respectively. When mouse tooth explants were cultured with antisense oligodeoxyribonucleotides (ODN) against mouse PTHrP mRNA in serum-free medium, an invasion of bone tissue was observed in the tooth germs. On the other hand, the explants cultured without ODN or with sense ODN showed normal histological structures similar to those observed in vivo. These results suggest that PTHrP is essential for tooth development and for the protection of tooth germs from the invasion of bone tissue.

Animals↗
PubMed1998

Immunohistochemical study of the innervation of the boundary area of the hard and soft palates of the rat.

The palatal mucosa plays an important role for patients using full dentures. The posterior ridge of the denture is designed to fit on the border between the hard and soft palates; accordingly, this boundary area is of importance when the outline of the denture is designed. In the present study, a rich supply of nerve fibers was found in the mucosa of the boundary area of the hard and soft palates of the rat. An immunocytochemical examination revealed nerve fibers containing protein gene product 9.5 (PGP 9.5), calcitonin gene-related peptide (CGRP), substance P (SP), pituitary adenylate cyclase-activating peptide, vasoactive intestinal polypeptide (VIP), C-terminal flanking peptide of neuropeptide Y (c-PON), or nitric oxide synthase (NOS). Thin nerve fibers with PGP 9.5, CGRP, or SP penetrated into the epithelium, reaching beneath the cornified layer and terminated as free nerve endings. VIP-, c-PON- and NOS-containing nerve fibers were distributed in the connective tissue. Many of the VIP- and c-PON-containing nerve fibers were associated with blood vessels. In addition, nerve fibers containing PGP 9.5, CGRP, SP and c-PON were observed around, and penetrating into, the taste buds in the boundary area.

Animals↗
PubMed1998

Effects of successful adenomectomy on body composition in acromegaly.

The purpose of the present study was to investigate postsurgical change in body composition in patients who have undergone surgery for acromegaly. Eight patients with acromegaly had determination of serum GH, insulin-like growth factor-I (IGF-I), height, body weight, and bioelectric impedance before surgery and at 2 weeks, 1 month, 3 months, and 6 months after surgery. Body composition was analyzed by bioelectric impedance analysis (BIA). We analyzed body fat (BF), body lean mass (BLM), body cell mass (BCM), total body water (TBW), intracellular water (ICW) and extracellular water (ECW). The serum GH concentration and IGF-I had decreased significantly 2 weeks after surgery. Body weight had decreased significantly 1 month after surgery and recovered 3 months after surgery. BIA showed that TBW and BCM had decreased significantly 2 weeks after surgery. BF gradually increased up to 1 month after surgery and was increased significantly at 3 months after surgery. The percent ratio of TBW/body weight decreased and the percent ratio of BF/body weight increased during the 6 months after surgery. The percent ratio of ECW/TBW did not change during the 6 months following surgery. In conclusion, the rapid body weight loss which occurred within 2 weeks after surgery was caused by decreases in TBW and BCM. The recovery of body weight, which was seen later than 1 month after surgery, was caused by an increase in BF. The postoperative change in body composition in acromegaly ceased 3 months after surgery.

Acromegaly↗
PubMed1998

Immunohistochemical localization of pleiotrophin and midkine in the lingual epithelium of the adult rat.

Distribution of two heparin-binding molecules, pleiotrophin (PTN) and midkine (MK), was investigated by immunohistochemistry in the lingual epithelium of the adult rat. In the lingual epithelium, both PTN- and MK-like immunoreactivities were observed in its basal cell layers, showing a mesh-like appearance. These molecules were also found along the surface of the taste bud cells; an intense immunoreaction was detected at the base of the taste buds in the circumvallate and foliate papillae. At the electron microscope level, the immunoreactive products were localized on the cell surface and basement membrane at the base of the taste buds. The immunoreactivity for PTN was distributed more diffusely than that for MK. It was suggested that these molecules may be involved in the differentiation and maintenance of taste bud cells, possible via their trophic effect upon approaching nerves.

Animals↗
PubMed1998

Subsidence of seizure induced by stereotactic radiation in a patient with hypothalamic hamartoma. Case report.

The authors report on a patient who exhibited intractable epilepsy due to an inaccessible hypothalamic hamartoma and subsequently underwent stereotactic radiosurgery. This 25-year-old man had a 24-year history of intractable gelastic and tonic-clonic seizures. Magnetic resonance (MR) imaging performed at examination as well as that performed 30 months earlier demonstrated a nonenhancing and nonprogressive spherical mass, approximately 10 mm in diameter, located on the patient's right side at the floor of the third ventricle. Focal radiation treatment performed with a gamma knife unit administered 36 Gy to the center and 18 Gy to the periphery of the lesion. This treatment resulted in an improvement in seizure control. Before the patient underwent radiosurgery, he suffered from three to six generalized seizures per month in spite of attentive compliance with an anticonvulsant medication regimen. After irradiation of the harmatoma, the frequency of the seizures transiently increased and then subsided 3 months posttreatment. The patient has been free of seizures for the last 21 months, with no neurological or endocrinological complications. Magnetic resonance imaging performed 12 months posttreatment demonstrated complete disappearance of the lesion.

Adult↗
PubMed1998

[Multivariate analysis of intentional temporary vessel occlusion in aneurysmal surgery].

Temporary vessel occlusion (TO) for aneurysmal clipping is an effective technique to facilitate dissection between aneurysm and parent vessels, and to place a permanent clip at the aneurysmal neck precisely. However, several unsolved problems remain regarding the overall safety and risk resulting from this technique. The authors examined a series of patients in whom mannitol 500 ml, tocopherol acetate 500 mg, and phenytoin 500 mg were administered intravenously as ischemic protection during TO for the aneurysmal clipping. The study comprises a nonconcurrent retrospective analysis of 144 consecutive aneurysm clippings performed with the aid of intentional TO at the Hiroshima Prefectural Hospital from 1985 to 1995. To identify technical and patient-specific risk factors for perioperative stroke, factors studied included duration, location of the temporary clip application, number of occlusive episodes, patient sex, age, and preoperative neurological status, timing of operation, as well as postoperative, temporary or permanent, neurological deficits (ND) due to TO were used. Overall frequency of postoperative ND due to TO manifested clinically and radiologically were 9.0% and 9.7%, respectively. In both univariate and multivariate analysis there were no significant factors relevant to the ND. However, duration of the temporary occlusion time over 20 minutes was the factor most influential on the ND due to TO. Duration of the temporary occlusion time was shown to have no link with outcome. Based on our findings the authors conclude that temporary vessel occlusion within 20 minutes with anti-ischemic drugs is a relatively safe adjunct to aneurysmal surgery.

Adult↗
PubMed1998

[A case of neurofibromatosis type I associated with basal meningocele and abnormal vessels].

A 21-year-old man with neurofibromatosis type 1 (NF 1) had many widespread cutaneous neurofibroma on his right face. Magnetic resonance imaging (MRI) revealed basal meningocele due to dysplasia of the skull base. Carotid and vertebral angiograms revealed occlusion of the right internal carotid artery, persistent primitive trigeminal artery. We have reviewed the clinical and radiographic features of this case of neurofibromatosis, meningocele and cerebral arterial abnormalities. NF associated with both intracranial vascular malformation and meningocele is very rare, and in our case both were thought to arise congenitally as a manifestation of mesodermal dysplasia. Careful follow up using MRI and MR angiography should be performed for such patients.

Adult↗
PubMed1998

[Hereditary diseases with tooth anomalies and their causal genes].

In this review, we describe the current knowledge and the advances in research on human genes whose defect leads to dental anomalies. Recently, it was demonstrated that a missense mutation of a human homeobox MSX1 gene causes autosomal dominant agenesis of second premolars and third molars. X-linked anhidrotic ectodermal dysplasia (EDA), characterized by abnormal hair, teeth, and sweat glands, was demonstrated to be caused by a mutation in a novel transmembrane protein gene that is expressed in epithelial cells and in other adult and fetal tissues. The autosomal dominant Rieger syndrome (RS) manifests hypodontia, adontia, iridogoniodysgenesis and umbilical anomalies. Recently, a novel homeobox gene, RIEG, of Otx family was cloned as a causal gene of RS. The several mutations have been reported on the genes causing hypophosphatasia, which is characterized by defective mineralization of the skeletal and dental structures. An autosomal dominant dentinogenesis imperfecta (DI) is mostly associated with osteogenesis imperfecta (OI). Most patients with DI have mutations in either the COL1A1 or COL1A2 genes of type I collagen. Amelogenesis imperfecta (AI) is a diverse group of hereditary disorders characterized by a variety of developmental enamel defects including hypoplasia and hypomineralization, some of which have been revealed to be associated with defective amelogenin genes.

Alkaline Phosphatase↗
PubMed1998

Ameloblast-lineage cells of rat tooth germs proliferate and scatter in response to hepatocyte growth factor in culture.

Hepatocyte growth factor (HGF) is considered to be one of the mediators of epithelial-mesenchymal interactions during early organogenesis and to be involved in the development of murine molars. In this study, the immunohistochemical localization of HGF and of its receptor, c-Met, revealed that HGF was distributed in the proliferating mesenchymal cells in the dental papillae and that c-Met was continuously expressed in the epithelial cells during the development of rat incisors. These observations confirmed the involvement of HGF in the development of rat incisors, as demonstrated previously in molars. We then used a primary culture of ameloblast-lineage cells, prepared from mandibular incisors of young rats, to examine the direct effects of HGF on the growth and differentiation of ameloblasts. We found that HGF at 2-20 ng/ml induced a marked increase in the number of ameloblast-lineage cells and in the scattering of such cells. Our results suggest that HGF promotes the proliferation and scattering of ameloblast-lineage cells simultaneously.

Ameloblasts↗
PubMed1997

Induction of osteogenic differentiation by hedgehog proteins.

In this study we asked whether members of the hedgehog gene family are involved in osteogenesis. C3H10T1/2 cells and MC3T3-E1 cells expressed the putative hedgehog receptor patched (Ptc) gene. Medium conditioned by chicken embryo fibroblast cultures expressing either Indian hedgehog or Sonic hedgehog stimulated alkaline phosphatase (APase) activity in cultures of the mouse mesenchymal cell line C3H10T1/2 and the osteoblastic cell line MC3T3-E1. These stimulatory effects were synergistically enhanced by bone morphogenetic protein-2 (BMP-2). Treatment with the amino-terminal portion of recombinant Sonic hedgehog proteins (rShh-N) up-regulated the expression of the Ptc gene within 12 h and increased production of APase in C3H10T1/2. rShh-N and BMP-2 also synergistically stimulated APase activity. rShh-N treatment did not affect the expression levels of Bmp-2, -4, -5, -6 and -7 genes. These findings indicate that hedgehog proteins directly act on osteogenic precursor cells and osteoblasts and stimulate osteogenic differentiation of these cells in co-operation with BMPs.

3T3 Cells↗
PubMed1997

Molecular targeting of mitomycin C chemotherapy.

In 10 human cancer cell lines, the activity of mitomycin C (MMC) was found to be determined by an interplay between activation by DT-diaphorase (DTD) and inactivation by glutathione S-transferase (GST). NADPH/cytochrome P-450 reductase was not responsible for MMC activation and expression of MDRI (Mr 170,000 P-glycoprotein), and MRP (multidrug resistance-associated protein) genes did not relate to MMC resistance. Gene expression analysis for NQO1 (DTD gene) and GSTpi predicted which enzyme activity predominated in a cell line, except K562 and K562/DOX. For tumors with DTD activity only, MMC given by itself was most active. In cell lines in which DTD action was predominant, tumor selectivity was achieved by enhancing DTD-mediated activation with m-iodobenzylguanidine and hyperglycemia, which reduced the intra-tumoral pH. KW2149, a novel MMC analogue activated by glutathione, was most active against tumors in which GSTpi predominated. These various enzyme-specific effects could be observed even in cell lines derived from tumors with multidrug resistance. Such MMC treatment based on cell enzymology may enhance significantly MMC efficacy, helping to overcome multidrug resistance.

Animals↗
PubMed1997

Regeneration of periodontal primary afferents of the rat incisor following injury of the inferior alveolar nerve with special reference to neuropeptide Y-like immunoreactive primary afferents.

Regeneration of primary afferents and the expression of neuropeptide Y (NPY) in the lingual periodontal ligament of the rat incisor were examined following different types of injury (resection or crush) of the inferior alveolar nerve (IAN) combined with superior cervical ganglionectomy. In normal animals, protein gene product 9.5 (PGP 9.5)-like immunoreactivity (-LI) was localized in the middle areas of the alveolus-related part of lingual periodontal ligament; some of these nerve fibers showed terminal ramification and morphologies resembling those of the periodontal Ruffini endings, and very few thin varicose NPY-like immunoreactive (-IR) nerve fibers were detected around the blood vessels. Three days following crush injury of the IAN, the number of PGP 9.5-IR nerve fibers decreased, then increased to the normal levels around 10-15 days following injury. NPY-IR primary afferents first appeared around 5 days following crush injury, increased in number gradually, reaching a peak around 14 days, and then decreased. No NPY-IR primary afferents were detected 56 days following crush injury of the IAN. The terminal morphology of NPY-IR primary afferents observed around 10-14 days following injury was similar to that of PGP 9.5-IR nerve fibers in the normal animals, but less expanded. The changes in distribution of PGP 9.5-IR and NPY-IR nerve fibers following resection were similar to those observed following crush injury but regeneration was slightly delayed. The present results suggest that injury-evoked NPY is closely associated with the regeneration process of mechanoreceptors in the periodontal ligament following injury of the IAN.

Animals↗
PubMed1997

Usefulness of three-dimensional phase contrast MR angiography on arteriovenous malformations.

Prospective three-dimensional phase contrast (3D-PC) MR angiography was obtained in 34 patients with arteriovenous malformations (AVM) and comparison was made between digital substraction angiography (DSA) and three-dimensional time-of-flight (3D-TOF) methods. Velocity encoding (VENC) for 3D-PC was adjusted to 60 and 10 cm/sec., and was changed only when adequate information was not obtained. VENC 60 cm/sec, demonstrated the main feeders in 100% of cases and the nidus in 86% of cases whereas VENC 10 cm/sec. showed the draining vein in 78% of cases. The detection rate of feeder, nidus and drainer was 60%, 40% and 13% respectively by the TOF technique. The mean size of the nidus as compared with DSA as standard was 130% with MRI, 108% with 3D-PC and 92% with the TOF technique and this difference was not statistically significant. 3D-PC was clearly superior in detecting AVM in the presence of hemosiderin, hematoma or surgical clips. It also showed gradual disappearance of the lesion after radiosurgery. We found 3D-PC superior to 3D-TOF in the diagnosis, therapeutic planning and follow-up of AVM.

Adolescent↗
PubMed1997

Usefulness of two-dimensional time-of-flight MR angiography combined with surface anatomy scanning for convexity lesions.

Thirty-eight patients with convexity lesions were studied prospectively with the two-dimensional time-of-flight (2D-TOF) magnetic resonance angiography (MRA) method. Of these 21 cases had additional surface anatomy scanning (SAS) and 7 cases had three-dimensional phase contrast (3D-PC) MRA. The findings were compared during surgery and the predictability of 2D-TOF evaluated. 2D-TOF was obtained with 2 mm slice thickness after the administration of contrast media for routine magnetic resonance imaging (MRI). Cortical veins were visualized with a good resolution with a scan time of only 5 minutes. The tumor was also visible in the background, due to enhancement, and thus the tumor-vessels relation was shown. Slow-flow vessels were also adequately seen. SAS was done at the same sitting with fast spin echo (FSE) with a scan time of 3 minutes. Once both images were incorporated, information on gyri and their relation to the lesions and vasculature could be obtained from a single image. We found 2D-TOF alone, or at times in combination with SAS, useful for planning of operation for convexity lesions.

Adolescent↗
PubMed1997

Incidence of intracranial aneurysm associated with pituitary adenoma.

The incidence of intracranial aneurysm associated with pituitary adenoma is not definitely established although reported higher than in general population. This study was designed to find the existence of such association in a large series of pituitary adenoma cases. A retrospective study of 467 cases of pituitary adenoma (mean age: 41 +/- 15 years) was done. All patients underwent cerebral angiography at least of anterior circulation, detailed hormonal study, and 155 cases had additional magnetic resonance (MR) angiography. Twenty-five cases (5.4%) of pituitary adenoma (mean age 52 years) had intracranial aneurysm, 97% on anterior circulation, and 12% had multiple aneurysms. Two cases presented with aneurysmal rupture and the rest were incidental. Aneurysm was more frequently seen with increasing age (p < 0.001) and the age distribution resembled that of aneurysm among general population. Although the combination was most frequent among nonfunctioning adenoma (8.8%), and least frequent among prolactinoma (2.4%), this association was again due to age factor. There was no association between hormone secretion, size and invasive nature of the tumor. The results showed no association between intracranial aneurysm and pituitary adenoma. Our speculation is that such occurrence is merely a chance factor and the risk is no greater than that among general population.

Adenoma↗
PubMed1997

MIB1 immunopositivity is associated with rapid regrowth of pituitary adenomas.

Pituitary adenomas are generally regarded as benign tumours, but they may recur. We identified eight patients with pituitary adenomas that showed rapid regrowth within 2 years of initial surgery. We estimated the percentage of cells in each specimen that showed positive immunostaining for MIB1 (a novel anti-Ki-67) and compared the values to those of 40 adenomas that showed no regrowth. The mean MIB1 index for 40 adenomas that showed no evidence of regrowth was 0.19 +/- 0.06%. This was significantly (p < 0.0001) lower than that for adenomas that showed rapid regrowth (1.27 +/- 0.31%), based on the initial resected specimens. Immediately after detection of rapid regrowth and in adenomas that were resistant to bromocriptine or irradiation, the MIB1 index was always greater than 1.0%. Most patients with rapidly regrowing adenomas were well controlled by radiation therapy. Our results suggest that a MIB1 index greater than 1.0% may be a useful predictor of rapid regrowth of pituitary adenomas and may be useful for planning of therapy.

Adenoma↗