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Biomedical subjects

K Sunami

Publications and source records attributed to K Sunami.

At least 19 recordsLinked to original sources
PubMed2003

MRI of ectopic posterior pituitary bright spot with large adenomas: appearances and relationship to transient postoperative diabetes insipidus.

MRI of large pituitary adenomas has revealed that a posterior pituitary bright spot (PPBS), comprising ADH-containing neurosecretory granules, is commonly ectopic before surgery and attached to the tip of the pituitary stalk late after surgery. Although the PPBS indicates functional integrity of the posterior lobe, transient diabetes insipidus (DI), caused by deficiency of ADH, is frequent early after surgery. We attempted to clarify how the shape, signal intensity and site of the PPBS before surgery are related to transient DI in the early postoperative period. We carried out MRI on 15 patients with a large adenoma and an ectopic PPBS before surgery and then within 1 week (early), 1-2 months (intermediate) and 6 or more months (late) after the operation. There were nine who had transient DI, which subsided by the intermediate study; none had permanent DI. Regardless of transient DI, the PPBS was visible, and its signal intensity was similar, on all postoperative studies. Although 11 did not change in shape, four showed a remarkable change from a flat shape before surgery to a rounded one postoperatively. On the intermediate MRI, the PPBS had descended to the level of the diaphragma as mass effect disappeared.

Adenoma↗
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

Demonstration of the optic pathway in large pituitary adenoma on heavily T2 weighted MR images.

The objective of the investigation was to understand preoperatively the detailed anatomical relationship of large pituitary adenomas to surrounding structures, using the heavily T2-weighted reversed (T2R) MR images. This study consisted of 28 patients with pituitary adenoma, presenting with visual disturbance. The MRI scanner used was a Gyroscan ACSNT 1.5T and the slice thickness of the image was 3 mm with 0.5 mm interslice gap. The relation of pituitary adenoma to optic pathway and to the degree of visual field defect was assessed. Relations of the optic chiasm to adenoma were classified into three types: anterior, superior and posterior. The optic chiasm was directly visualized and identifiable in all patients studied. It was located anterior in four cases, superior in 22 and posterior in two in relation to the adenoma. Its location was further confirmed by the anatomical delineation of surrounding structures such as anterior commissure and lamina terminalis. Optic nerve or tract was unidentifiable in one case, for each category. Detectability of each optic component was higher on T2R images than on conventional T1-weighted images. The adenoma extended into and in front of the third ventricle in anterior and posterior types, respectively. The anterior communicating artery complex and the optic pathway were relocated together in anterior and superior types, and were separated in the posterior type. In a case of the posterior type, the complex was sectioned to obtain a wider surgical field during anterior interhemispheric approach. While degrees of visual field defect were proportional to tumour size in the superior type, they were unrelated in the anterior and posterior types. On choosing a transcranial approach, the transcallosal route is unsuitable for an adenoma of posterior type, which extends in front of the third ventricle. This preoperative MRI information makes it possible to visualize directly the optic pathway even in huge adenomas, and is useful in predicting surgical anatomy and selecting a proper surgical approach.

Adenoma↗
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

Administration of granulocyte colony-stimulating factor induces hyporesponsiveness to lipopolysaccharide and impairs antigen-presenting function of peripheral blood monocytes.

OBJECTIVE: The incidence and severity of acute graft-vs-host disease after allogeneic transplantation of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood stem cells (PBSC) are not greater than those after conventional bone marrow transplantation despite infusion of more than one log greater number of donor T cells in PBSC. It has been postulated that monocytes from G-CSF-mobilized donors suppress alloreactivity of donor T cells. MATERIALS AND METHODS: We investigated the phenotype and function of monocytes in normal individuals receiving 10 microg/kg of G-CSF for 4 days. RESULTS: Monocytes were phenotypically and functionally different after G-CSF administration from steady-state monocytes. They were characterized by an increased CD14(+)CD16(+) subpopulation, reduced expression of HLA-DR, and diminished ability to produce tumor necrosis factor-alpha and interleukin-10 to lipopolysaccharide, compared with steady-state monocytes. These alterations were not replicated by culturing monocytes with G-CSF in vitro, suggesting an indirect effect of G-CSF. In addition, the antigen-presenting function of G-CSF-mobilized monocytes was impaired. CONCLUSION: Hyporesponsiveness of G-CSF-treated monocytes to lipopolysaccharide with regard to tumor necrosis factor-alpha production, together with impaired antigen-presenting function, may be responsible for the unexpectedly low incidence of graft-vs-host disease after G-CSF-mobilized PBSC transplantation.

Antigen Presentation↗
PubMed2001

Hepatic graft-versus-host disease presenting as an acute hepatitis after allogeneic peripheral blood stem cell transplantation.

Hepatic graft-versus-host disease (GVHD) generally presents as cholestatic jaundice, and increased serum alkaline phosphatase (ALP) is followed by hyperbilirubinemia and clinical jaundice. Currently accepted standards for evaluating the clinical severity of GVHD are based not on serum aminotransferase levels but on the serum bilirubin level. We describe a 17-year-old Japanese female who had increased aminotransferases without cholestasis on day 23 after allogeneic peripheral blood stem cell transplantation (allo-PBSCT). Liver biopsy revealed lymphocytic infiltration of the portal tracts and pericentral necrosis of the lobuli. The limiting plates were not clearly defined due to cellular infiltrates. There was periductal lymphocytic infiltration and vacuolization of the biliary epithelial cells with exocytosis, compatible with GVHD of cholangiohepatitic type. These findings indicate that acute hepatic GVHD may present as acute hepatitis and this should be included in the differential diagnosis for patients with increased aminotransferases after allogeneic stem cell transplantation.

Acute Disease↗
PubMed2001

Temporal profiles of the levels of endogenous antioxidants after four-vessel occlusion in rats.

Although it is known that development of lipid peroxidation after ischemia occurs predominantly in vulnerable regions, temporal profiles of antioxidants after ischemia have not been regionally elucidated. After reperfusion periods of 0, 3, 24, and 72 hours following 20 minutes of four-vessel occlusion (n = 6 in each group), the concentration of total glutathione (GSH) and the activities of superoxide dismutase (SOD), catalase, and glutathione peroxidase (GSH-Px) were assayed in the hippocampus, parietal cortex, striatum, thalamus, and brain stem. The levels of all antioxidants were unchanged in all regions without reperfusion; however, the concentration of total GSH significantly decreased in the hippocampus at 3 hours after the onset of reperfusion, and showed a maximum decrease in the hippocampus (68% of the sham-control level), parietal cortex (78% of the sham-control level), and striatum (76% of the sham-control level) after 24 hours of reperfusion. After 72 hours of reperfusion, these regions and the thalamus showed restoration and an increase in the total GSH concentration, respectively. The activities of SOD, GSH-Px, and catalase were stable during the reperfusion period, but the hippocampus showed significant increases in these enzyme activities and the parietal cortex and striatum showed significant increases in SOD activities at 72 hours after the onset of reperfusion. These results indicate that endogenous antioxidants take 72 hours for restoration in vulnerable regions after 20 minutes of four-vessel occlusion in rats.

Animals↗
PubMed2001

Heavily T2-weighted MR imaging of white matter tracts in the hypothalamus: normal and pathologic demonstrations.

BACKGROUND AND PURPOSE: The MR appearance of white matter tracts in the hypothalamus and the role of the hypothalamus as a memory mechanism have not been sufficiently described in clinical settings. Heavily T2-weighted black-and-white reversed (T2R) images were assessed to reveal their visualization and clinical significance. METHODS: One hundred healthy subjects and three patients with hypothalamic lesions underwent fast spin-echo MR imaging to reveal the postcommissural fornix (PF) and mammillothalamic tract (MT). RESULTS: The PF was identifiable in axial and/or coronal sections in all healthy subjects. No remarkable asymmetry of its size or course was evident. Both anteroposterior and vertical dimensions ranged from 10.5 to 14 mm. The MT was visible in one or two axial sections above the mammillary body in 64% of healthy subjects and in a coronal section in 36%. Two patients with glioblastoma multiforme and lacunar infarct at the hypothalamus presented with anterograde amnesia; T2R imaging revealed involvement of both the PF and MT. The third patient had a suprasellar craniopharyngioma with PF injury sparing the MT resulting from surgical manipulation and was free of memory deficit. Anterograde amnesia was evident only when both the PF and MT were injured. CONCLUSION: T2R images have made a high rate of detection of the PF and MT possible and could provide a more detailed correlation of hypothalamic neuroanatomy and memory mechanism in clinical settings.

Adolescent↗
PubMed2000

Neuroradiological characteristics of pineocytoma and pineoblastoma.

We reviewed neuroradiological images in two histologically proven cases of pineocytoma and three of pineoblastoma to delineate the characteristic features of these rare tumours. CT revealed isodense or slightly hyperdense masses with central or peripheral calcification; enhancement with contrast medium tended to be homogeneous in pineocytomas and heterogeneous in pineoblastomas. In the pineocytomas, T1-weighted images revealed rounded, sometimes or slightly lobulated low-signal masses with strong, homogeneous contrast enhancement. Their margin was clear, without invasion of adjacent structures. In the pineoblastomas, however, T1-weighted images revealed multilobulated tumours with heterogeneous contrast enhancement. All three pineoblastomas had poorly defined margins with adjacent structures such as the posterior thalamus or corpus callosum, suggesting a more invasive nature. T2-weighted images revealed nonspecific high signal lesions in all five cases.

Adult↗
PubMed2000

G-CSF reduces IFN-gamma and IL-4 production by T cells after allogeneic stimulation by indirectly modulating monocyte function.

Despite a 10-fold increase of T cell dose, the incidence and severity of acute GVHD following allogeneic transplantation of G-CSF-mobilized PBSC is not increased compared to BMT. Experimental murine studies demonstrate that G-CSF polarizes donor T cells toward a type 2 cytokine response. To determine whether G-CSF alters T cell cytokine responses, we investigated the effects of G-CSF administration on T cell proliferative and cytokine responses to alloantigen and Con A in nonadherent PBMC (NAC) and CD3+ T cells obtained from normal individuals before and after G-CSF administration (10 microg/kg x 4 days). Although T cell proliferative and cytokine (IFN-gamma and IL-4) responses to alloantigen stimulation and Con A were significantly reduced in post-G-CSF NAC, they were restored by the removal of non-T cells from post-G-CSF NAC. Furthermore, there was less T cell alloreactivity in MLR in the presence of autologous post-G-CSF monocytes than in the presence of pre-G-CSF monocytes. This alteration was not replicated in vitro by culturing PBMC with G-CSF. These results suggest that G-CSF administration suppresses T cell proliferative and cytokine (IFN-gamma and IL-4) responses to allogeneic stimulation by indirectly modulating monocyte function. Bone Marrow Transplantation (2000).

Adult↗
PubMed2000

Allogeneic peripheral blood stem cell transplantation for the treatment of chronic active Epstein-Barr virus infection.

The prognosis of chronic active Epstein-Barr virus infection (CAEBV) is very poor. We describe a 24-year-old male with severe CAEBV who was treated with allogeneic peripheral blood stem cell transplantation (allo-PBSCT). On admission, EBER-1 in lymphocytes infiltrating the liver, EBV-DNA in peripheral blood mononuclear cells (PBMC) and monoclonal NK cell proliferation were confirmed. After unsuccessful chemotherapy, he received an allo-PBSCT from his HLA-identical sister. Although he died of pulmonary hemorrhage on day +19, EBV-DNA was undetectable by PCR in PBMC, and the post-mortem liver showed no EBER-1-positive lymphocytes. This experience suggests that EBV-positive lymphocytes in CAEBV may be eradicated by allo-PBSCT, thereby raising the possibility of a new treatment modality. Bone Marrow Transplantation (2000) 26, 805-808.

Adult↗
PubMed2000

Growth hormone secreting adenoma with unusual extension: coexisting pituitary cyst and its clinical significance.

A 58 year old man showed acromegalic features. The serum growth hormone (GH) level was 7.3 ng/ml and SMC (somatomedin-C) 637 U/ml. Triple stimulation test showed abnormal response compatible with a GH secreting tumour. The conventional enhanced MRI revealed a less enhanced hemisphere-shaped lesion at the right corner of the sella turcica. In addition, dynamic MRI demonstrated an elongated lesion extending to the left beyond the midline. The patient underwent transsphenoidal surgery. Besides the soft and suckable tumour at the right corner, we entered into a small cavity loosely filled with the tumour, which was subsequently also removed. The operative finding corresponded to the lesion shown in dynamic MRI. Postoperative GH and SMC levels became 2.3 ng/ml and 326 U/ml respectively. Incidental pituitary cystic lesions in autopsied cases have been reported to be 6-33%. This case had a GH secreting adenoma with coexisting pituitary cyst. The coexisting pituitary cyst supposedly influenced the unusual shape and extension of the pituitary adenoma. Coexistence of such lesion should be kept in mind for microadenoma on neuroradiological evaluation and on intraoperative inspection surrounding the tumour.

Adenoma↗
PubMed2000

Rathke's cleft cyst with large frontal extension: unusual shape and pathomechanism of its formation.

The patient was a 62 year old woman who presented with a visual field defect. Magnetic resonance images showed an intra-and supra-sellar low intensity mass on T1 weighted images. The preoperative diagnosis was craniopharyngioma, Rathke's cleft cyst (RCC) or arachnoid cyst. The patient underwent transsphenoidal surgery & the pathological diagnosis was RCC. We conclude that although RCC has a round, ovoid or dumb-bell shaped configuration, it may present a unusual shape in cases with preconditions, as were seen in our patient.

Central Nervous System Cysts↗
PubMed2000

Hyperbaric oxygen reduces infarct volume in rats by increasing oxygen supply to the ischemic periphery.

OBJECTIVE: Hyperbaric oxygen (HBO) increases oxygen supply to anoxic areas. To examine the therapeutic effect of HBO on ischemic stroke, we measured infarct volume as well as cerebral blood flow (CBF), oxygen supply, and lipid peroxidation in the ischemic periphery. DESIGN: Prospective experimental study in rats. SETTING: Experimental laboratory in a university teaching hospital. SUBJECTS: Thirty-eight adult rats. INTERVENTION: The rats were anesthetized (1% halothane) and intubated. Focal ischemia was induced by ligating the right middle cerebral and right common carotid arteries. Nineteen animals were exposed to 2 hrs of HBO (100% oxygen, 3 atmospheres absolute), initiated 10 mins after the onset of ischemia. The remaining animals were kept at ambient pressure and used as controls. MEASUREMENTS AND MAIN RESULTS: At the initiation of ischemia, CBF measured by a laser-Doppler flow probe placed in the ischemic periphery was reduced to 47%+/-11% and 51%+/-15% of normal levels in animals exposed or not to HBO, respectively. These altered values were not affected further by administration of HBO and remained stable throughout a 2-hr observation period. Arterial oxygen pressure and content were significantly increased to 1571+/-130 torr (209.41+/-17.32 kPa; p < .0001) and 1.03+/-0.04 mmol/dL (p < 0.0001), respectively, in HBO-treated animals compared with nontreated animals (139+/-14 torr [18.53+/-1.87 kPa] and 0.86+/-0.04 mmol/dL, respectively). The calculated increase in the oxygen supply to the ischemic periphery was 20%. The infarct volume of HBO-treated animals measured 24 hrs after the onset of focal cerebral ischemia was significantly reduced by 18% (HBO-treated, 132+/-13 mm3 vs. nontreated, 161+/-29 mm3; p = .02). Lipid peroxidation was unchanged after 120 mins of HBO administration in the cerebral cortex where the laser-Doppler flow probe was placed. CONCLUSIONS: HBO at 3 atmospheres absolute reduced infarct volume by increasing oxygen supply to the ischemic periphery without aggravating lipid peroxidation, suggesting that HBO can be useful in treating stroke victims.

Animals↗
PubMed2000

Bilateral ptosis with pupil sparing because of a discrete midbrain lesion: magnetic resonance imaging evidence of topographic arrangement within the oculomotor nerve.

The topographic arrangement within the midbrain oculomotor nerve is not adequately elucidated in humans. Two patients with a partial oculomotor palsy because of a localized infarction or hematoma were treated. Both patients had bilateral ptosis, impaired adduction, and supraduction. One patient had impaired infraduction and pupillary involvement on one side. Results of computed tomography and magnetic resonance imaging revealed discrete lesions at the dorsal midbrain tegmentum that spared the rostral midbrain. The authors' cases elucidate that pupillary components take the most rostral course. This report provides indirect magnetic resonance imaging evidence to prove the course of pupillary fibers. Based on the different neuro-ophthalmologic findings in the authors' cases (sparing or affecting pupillary component and infraduction), the nerves of the inferior rectus and inferior oblique for infraduction pass more rostrally than those of medial rectus, superior rectus, and levator palpebrae. The nuclear and fascicular arrangement within the midbrain oculomotor nerve is speculated to be pupillary, extraocular, and eyelid elevation in the rostro-caudal order, based on the neuro-ophthalmologic impairment and magnetic resonance imaging findings in the authors' patients and in previous animal experiments. Knowing the fascicular and nuclear arrangement within the midbrain in detail will offer diagnostic clues for differentiation of causes for partial oculomotor palsy.

Aged↗
PubMed2000

Incidence of malignant tumors in patients with acromegaly.

Neoplasms may be one of the systemic complications to which we attribute high mortality in acromegaly. The present study was designed to investigate the incidence of malignant tumors in patients with acromegaly in the Japanese population. In this report, 44 patients (25 men and 19 women) with biochemically proven acromegaly were studied retrospectively and had a total 670 patient years of the duration of acromegaly. We investigated the incidence of malignant tumors. There were 5 patients with malignant tumors (5 in men) in this study (11%). Male patients with acromegaly had nearly a 3.5 times higher ratio of malignancy than expected and this increased cancer incidence was considered significant (P=0.01). There was no significant increase in cancer incidence of either the total patient population or female patients. The malignant tumors were two thyroid cancers and one colon, one gastric and one bladder cancer. It is of note that the colon cancer of one patient was diagnosed 2 years after transsphenoidal surgery even though the levels of serum GH and insulin-like growth factor (IGF-1) were reduced to normal after operation. This preliminary study has suggested that male patients with acromegaly might have a high risk of malignancy and that careful screening for tumors is needed both before and after surgical and medical treatment, even in patients with normalized serum GH and IGF-1 levels.

Acromegaly↗
PubMed2000

Bone CT evaluation of nasal cavity of acromegalics--its morphological and surgical implication in comparison to non-acromegalics.

PURPOSE: In order to numerically compare the morphological differences of the nasal cavity and nasal sinus between acromegalics and non-acromegalics, bone window CT scans sliced parallel to the transsphenoidal surgical route were performed. MATERIAL AND CASES: Acromegalic patients had small or large macroadenomas and were 13 (7 men and 6 women) in number, aged 53.2 +/- 16.1 years. Non-acromegalic patients had pituitary tumors and were 44 (21 men and 23 women) in number, aged 52.1 +/- 12.5 years. RESULTS: The results of acromegalics are described in comparison to non-acromegalics in parentheses. a) The width of the surgical corridor: piriform aperture, 27.6 +/- 2.7 (25.9 +/- 2.6) mm; origin of inferior nasal concha, 29.4 +/- 9.4 (26.6 +/- 4.0) mm; and origin of middle nasal concha, 29.8 +/- 3.2 (26.2 +/- 4.2) mm. b) The depth of the surgical corridor: the upper lip thickness, 18.1 +/- 2.7 (13.3 +/- 1.4) mm; the distances between piriform aperture and sphenoid wall, 52.9 +/- 4.6 (49 +/- 4.2) mm; sphenoid wall and sellar floor, 17.3 +/- 4.1 (18.7 +/- 4.1) mm; and sellar floor to dorsum sellae, 17.6 +/- 3.4 (15.6 +/- 4.0) mm. c) Marked carotid prominence: 7/13=53.4% (8/44=18.25%). d) Sinusitis: 8/13=61.5% (12/44=27.3%). DISCUSSION & CONCLUSION: The data presented above show that morphological differences in bony nasal cavity and soft tissue may be responsible for a deeper and narrower surgical field for acromegalics. Acromegalics had a marked carotid prominence more frequently, which needs special attention to avoid carotid injury, when enlarging the surgical field. Knowing these morphological differences will provide useful information for peri- and intra-operative care.

Acromegaly↗