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Biomedical subjects

A Teramoto

Publications and source records attributed to A Teramoto.

At least 91 records · Page 5Linked to original sources
PubMed1999

Pit-1 positive alpha-subunit positive nonfunctioning human pituitary adenomas: a dedifferentiated GH cell lineage?

Pit-1 is a transcription factor which has been reported to regulate differentiation toward GH, PRL and TSH in the anterior pituitary glands. In the human pituitary adenomas, Pit-1 is highly expressed in GH secreting and TSH secreting adenomas as it can well be anticipated. Interestingly, human non-functioning pituitary adenomas also express Pit-1, especially it was expressed in all alpha SU positive nonfunctioning adenomas. The human anterior pituitary cells are special in comparison with rodents in a finding that alpha SU is frequently colocalized with GH. As alpha SU is the first hormone appearing during fetal development in the rodent pituitary glands, it may be postulated that alpha SU Pit-1 positive cells undergo differentiation in the GH cell lineage. From this background, this paper proposes that "alpha SU positive Pit-1 Positive" cells are the ones in the GH cell lineage, more specifically a dedifferentiated cell lineage toward alpha SU/GH/Pit-1.

Adenoma↗
PubMed1999

Ectopic corticotroph adenoma in the cavernous sinus: case report.

OBJECTIVE AND IMPORTANCE: Adrenocorticotropin (ACTH)-secreting pituitary adenomas causing Cushing's disease are often difficult to identify because of their variable locations and their small size. This report presents histological evidence of an ectopic ACTH-secreting adenoma located entirely within the cavernous sinus. CLINICAL PRESENTATION: A 62-year-old woman presented with central obesity, hypertension, and osteoporosis. Endocrinological evaluation suggested the presence of an ACTH-secreting pituitary adenoma; however, imaging studies, including dynamic magnetic resonance imaging, did not reveal any visible lesions in the pituitary gland. Bilateral cavernous sinus sampling demonstrated a large central/peripheral ACTH gradient, with a right/left ACTH gradient. The patient was treated as having pituitary-dependent Cushing's disease, until she died suddenly as a result of acute respiratory failure. INTERVENTION: In a postmortem histological examination, an ACTH-secreting adenoma was found in the right cavernous sinus, which was completely surrounded by dura mater and had no direct connection with the pituitary gland. CONCLUSION: Although they are rare, such adenomas located in the cavernous sinus should be recognized as one of the reasons for inaccurate cavernous sinus sampling and the failure of transsphenoidal surgery for patients with ACTH-dependent Cushing's syndrome.

ACTH Syndrome, Ectopic↗
PubMed1999

Heterozygous gsp mutation renders ion channels of human somatotroph adenoma cells unresponsive to growth hormone-releasing hormone.

Ionic mechanisms play an important role in the regulation of hormone secretion. The GHRH-induced GH release by human GH-secreting cells is transmitted through protein kinase A (PKA), which activates nonselective cation current (NSCC) and induces membrane depolarization, intracellular Ca2+ increase, and GH secretion. To evaluate whether ionic mechanisms have pathophysiological significance in GH oversecretion of GH-secreting pituitary adenomas, we examined four adenomas with constitutively active Gs alpha mutation (gsp mutation) and compared with three gsp-negative adenomas. In primary-cultured cells of gsp-positive adenomas, GHRH did not increase the NSCC under voltage-clamp experiments. Detailed examination showed that NSCC was maximally activated at the basal level and application of GHRH did not increase the current in these adenomas. Furthermore, by using single-cell RT-PCR method, we demonstrated for the first time at the single cell level that gsp mutation is heterozygous in GH-secreting pituitary adenomas. These indicate that heterozygous gsp mutation fully activates NSCC at the basal level, which may account for the GH oversecretion in gsp-positive GH-secreting pituitary adenomas.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1999

Serum concentration of 20K human growth hormone (20K hGH) measured by a specific enzyme-linked immunosorbent assay. Study Group of 20K hGH.

Several GH isoforms have been identified in pituitary and serum, the most abundant of which is the 22K human GH (hGH) isoform. The 20K hGH isoform is produced by alternative splicing of GH messenger ribonucleic acid and comprises approximately 10% of all GH in the pituitary. The physiological role of 20K hGH remains to be determined, partly because of the lack of a simple and specific assay. We have established sensitive enzyme-linked immunosorbent assays (ELISAs) specific to 20K and 22K hGH. To determine whether regulation of 20K hGH secretion is the same as that for 22K hGH, we measured serum concentrations of both species of hGH in normal subjects and patients with a variety of endocrine disorders. The serum levels of 20K hGH after overnight fasting was 118 +/- 178 pg/mL (n = 282) in normal women, significantly higher than that in normal men (64 +/- 170 pg/mL; n = 226). However, there was no difference in the proportion of 20K hGH to 20K plus 22K hGH between men (6.3 +/- 2.6%, mean +/- SD; n = 176) and women (6.3 +/- 2.1%; n = 263). No correlation was detected between the ratio of 20K hGH and age, body height, body weight, or body fat mass in normal subjects. The proportion of 20K hGH was significantly (P < 0.001) higher in patients with active acromegaly (9.2 +/- 2.2%; n = 33) and patients with anorexia nervosa (9.0 +/- 1.9; n = 8), both of which are characterized by chronic elevation of circulating GH levels. The proportion of 20K hGH in successfully treated acromegalic patients did not differ from that in normal subjects, suggesting that GH-producing pituitary tumors secrete a higher proportion of 20K hGH, or that a chronic excess of 22K hGH alters the MCR of 20K hGH. The values in patients with adult GH deficiency, hyperthyroidism, primary hypothyroidism, or GH-independent short stature did not differ from those in normal subjects. The 20K ratio did not change after acute GH provocative tests, such as the insulin tolerance test and the GHRH test. These results suggest that secretion of 20K hGH from the pituitary is under the same control as that of 22K hGH. This new assay may provide a tool for understanding the physiological or pathophysiological role of the 20K hGH isoform.

Acromegaly↗
PubMed1999

Ruptured aneurysm of the orbitofrontal artery associated with dural arteriovenous malformation in the anterior cranial fossa--case report.

A 27-year-old male presented with a rare association of a ruptured orbitofrontal artery aneurysm and a dural arteriovenous malformation (DAVM) fed by both ethmoidal arteries, manifestation as severe headache, nausea, and vomiting. Computed tomography revealed a hematoma within the right frontal lobe and diffuse subarachnoid hemorrhage. The aneurysm was clipped successfully and the hematoma was evacuated. After an uneventful postoperative course, the patient was referred for gamma knife radiosurgery to treat the DAVM. In this case, the DAVM was asymptomatic and pathogenetically unrelated to the aneurysm, which demanded urgent treatment.

Adult↗
PubMed1999

Three-dimensional computerized tomography angiography in patients with hyperacute intracerebral hemorrhage.

OBJECT: The authors confirm the usefulness of extravasation detected on three-dimensional computerized tomography (3D-CT) angiography in the diagnosis of continued hemorrhage and establishment of its cause in patients with acute intracerebral hemorrhage (ICH). METHODS: Thirty-one patients with acute ICH in whom noncontrast and 3D-CT angiography had been performed within 12 hours of the onset of hemorrhage and in whom conventional cerebral angiographic studies were obtained during the chronic stage were prospectively studied. Noncontrast CT scanning was repeated within 24 hours of the onset of ICH to evaluate hematoma enlargement. Findings indicating extravasation on 3D-CT angiography, including any abnormal area of high density on helical CT scanning, were observed in five patients; three of these demonstrated hematoma enlargement on follow-up CT studies. Thus, specificity was 60% (three correct predictions among five positives) and sensitivity was 100% (19 correct predictions among 19 negatives). Evidence of extravasation on 3D-CT angiography indicates that there is persistent hemorrhage and correlates with enlargement of the hematoma. Regarding the cause of hemorrhage, five cerebral aneurysms were visualized in four patients, and two diagnoses of moyamoya disease and one of unilateral moyamoya phenomenon were made with the aid of 3D-CT angiography. Emergency surgery was performed without conventional angiography in one patient who had an aneurysm, and it was clipped successfully. CONCLUSIONS: Overall, 3D-CT angiography was found to be valuable in the diagnosis of the cause of hemorrhage and in the detection of persistent hemorrhage in patients with acute ICH.

Acute Disease↗
PubMed1999

Expression of Rab3, a Ras-related GTP-binding protein, in human nontumorous pituitaries and pituitary adenomas.

Rab proteins are low molecular weight GTP-binding proteins. Among these proteins, the Rab3 isoforms are considered to be involved in the exocytosis of synaptic vesicles and secretory granules in the central nervous system and anterior pituitary gland. In recent reports, the expression of Rab3 isoforms in anterior pituitary glands of mammalian species was extensively investigated. In the present study, we investigated the localization of Rab3 protein in 5 human nontumorous pituitaries and 114 human pituitary adenomas using immunohistochemical methods. In five human nontumorous pituitaries, Rab3 protein was expressed in the cytoplasm of anterior pituitary cells. Double staining for anterior pituitary hormones revealed the expression of Rab3 in growth hormone-secreting cells, but rare expression was observed in the other anterior pituitary hormone-secreting cells. Among the pituitary adenomas, 71 (62.3%) of 114 pituitary adenomas were positive for Rab3. Among the different pituitary adenoma types, the incidence of Rab3 immunopositivity was highest in growth hormone-secreting adenomas (100%), followed by adrenocorticotropic hormone-secreting adenomas (71.4%), thyroid-stimulating hormone-secreting adenomas (57.1%), nonfunctioning adenomas (56.0%), and prolactin-secreting adenomas (33.3%). After an embedding immunoelectron microscopic study, Rab3 was localized along the limiting membrane of secretory granules in the Rab3-positive pituitary adenomas. Western blotting showed the molecular weight of Rab3 to be 25 kDa in the pituitary adenomas, which were immunohistochemically positive for Rab3 protein. These results suggested that Rab3 might be involved in regulating the exocytosis of secretory granules of the anterior pituitary cells, especially growth hormone-secreting ones, which are particularly characterized by densely granulated cytologic features.

Adenoma↗
PubMed1999

[Efficacy of three dimensional CT angiography (3D-CTA) for a first diagnosis of occlusive cerebrovascular disorders].

Patients with cerebrovascular disorders generally undergo computerized tomography (CT), even though magnetic resonance imaging (MRI) is available. We investigated the efficacy of three dimensional CT angiography (3D-CTA) for a first diagnosis of occlusive cerebrovascular disorders. Sixty-two patients, who were suspected of occlusive cerebrovascular disorder on the basis of neurological findings or initial plain CT findings, were reviewed. 3D-CTA was performed at the first medical examination. As a result, two patients were diagnosed with ICA (internal carotid artery) occlusion, nine with MCA (middle cerebral artery) occlusion, and one with BA (basilar artery) occlusion. All twelve patients underwent cerebral angiography immediately after those 3D-CTA in every case. Angiographical findings were the same as 3D-CTA. Interventional superselective thrombolytic therapy was performed in ten of the twelve patients, and recanalization resulted in four of them. 3D-CTA may also be able to determine whether the occlusive vessel is the chief cerebral artery or the perforating artery.

Adult↗
PubMed1999

[Occipital neuralgia caused by the compression of the fenestrated vertebral artery: a case report].

A case is presented of fenestration of the vertebral artery in a 36-year-old woman who had various neurological symptoms with Basedow's disease. We also review 7 cases from the literature. Our patient had had occipital neuralgia and numbness of the left side of the neck and left upper limb several weeks before admission. On admission she had hyperthyroidism. MRI, left vertebral angiography, and 3D-CT scans demonstrated a fenestrated vertebral artery compressing the upper cervical cord. The patient's symptoms gradually improved as her thyroid function was controlled. A possible explanation is that the fenestrated vertebral artery might have compressed the neural structures, resulting in her various symptoms. Occipital neuralgia was apparently caused by the fenestrated artery compressing the C1 and C2 sensory roots. A fenestrated vertebral artery is usually of no clinical significance. The reason for the late onset of symptoms in the present case is unknown, but it may have been due to hemodynamic stress caused by her hyperthyroidism. After her thyroid function was controlled, the hemodynamic stress presumably decreased and the symptoms resolved spontaneously.

Adult↗
PubMed1999

[Cerebral blood flow (CBF) before and after cranioplasty performed during the chronic stage after decompressive craniectomy evaluated by xenon-enhanced computerized tomography (Xe-CT) CBF scanning].

Patients who undergo decompressive craniectomy for the purpose of prevention of cerebral herniation sometimes improve neurologically or increase activity of daily life after cranioplasty during the chronic stage. We studied the effect which cranioplasty at the chronic stage had on intracranial environment by means of xenon-enhanced computerized tomography (Xe-CT) CBF scanning. Eight patients underwent decompressive craniectomy at the acute stage and cranioplasty at the chronic stage was reviewed. Xe-CT CBF scanning was performed before and after cranioplasty. On the slice of the basal ganglia. CBF of the symptomatic hemisphere increased in five patients and CBF of the other hemisphere increased in three patients after cranioplasty. On the slice 20 mm above the basal ganglia, CBF of the symptomatic hemisphere increased in five patients and CBF of the other hemisphere increased in four patients after cranioplasty. Cranioplasty after decompressive craniectomy may increase CBF of not only the symptomatic hemisphere but also the other hemisphere.

Aged↗
PubMed1999

[Moyamoya disease with intraventricular hemorrhage due to rupture of lateral posterior choroidal artery aneurysm: case report].

Intracranial aneurysms associated with moyamoya disease are often reviewed. Aneurysms not around the circle of Willis but on the collateral vessels are rare. A 71-year-old woman presented with sudden onset of severe headache and vomiting. CT scan showed an intraventricular hemorrhage from bilateral lateral ventricle to fourth ventricle. Cerebral angiography showed the occlusion of the terminal portion of the bilateral internal carotid artery with moyamoya vessels and three aneurysms at the distal portion of the left lateral posterior choroidal artery. Clinical symptoms improved day by day, but 17 days later, due to rebleeding of the aneurysms the patient fell into coma. The day after rebleeding, endovascular embolization was performed using liquid particle, and the left lateral posterior choroidal artery and the aneurysm were occluded. Brain infarction with massive brain edema of the left cerebral hemisphere resulted in the patient's death. The management of the aneurysms in the basal ganglia and on the collateral vessels associated with moyamoya disease is controversial. We suggest positive intervention during the acute stage for the peripheral artery aneurysms taking endovascular embolization into consideration to prevent rupture or rebleeding.

Aged↗
PubMed1999

[Use of fluid-attenuated inversion recovery (FLAIR) images in brain check-up].

Fluid-attenuated inversion recovery (FLAIR) images are magnetic resonance (MR) images obtained with an inversion recovery sequence having a long inversion time (T 1) and a long echo time (TE). The purpose of this study was to evaluate the utility of FLAIR images in brain check-up. 320 healthy adults (229 males, 91 females) were examined with FLAIR sequences of several types having repetitive time (TR) of 7000 msec, inversion times of 1700 msec and echo times (TE) of 110 msec. All studies were performed on a SHIMAZU MAGNEX 100 HP 1.0 T imaging system. FLAIR images were useful in detecting cortical and subcortical lesions near the brain surface, which were unclear in the conventional T 2 weighted images. FLAIR images were useful in evaluation of periventricular hyperintensity area (PVH). Frequency and degree of PVH were increased in aging. FLAIR images were useful in the differential diagnosis of lacuna and perivascular space. In conclusion, FLAIR images were very sensitive for the detection of brain lesions in brain check-up.

Adult↗
PubMed1998

Quantitative analysis of pro- and anti-inflammatory cytokine mRNA in neural graft rejection.

The central nervous system (CNS) has been considered an immunologically privileged site. However, this concept is now changing because rejection of histoincompatible neural grafts is commonly observed in the CNS. To be able to use neural transplantation as therapy for human diseases, it is important to determine factors that are related to brain-graft rejection. In the present study, we examined the phenotype of infiltrating T cells around grafts in the cerebra that had received xenogeneic (mouse to rat) neural transplants. Furthermore, the amount of pro- and anti-inflammatory cytokine mRNA was determined by competitive PCR at various time points after the neural transplantation. Immunohistochemical examination revealed that both CD4-positive and CD8-positive T cells infiltrated the CNS parenchyma. In competitive PCR analysis, levels of IFN-gamma and perforin in xenografts on days 10 and 13 post-transplantation (PT) were higher than those in isografts (rat to rat) at the same stage, whereas the levels of TNF-alpha, which was detected only on day 7 PT, were not significantly different between the two groups. With regard to anti-inflammatory cytokines, TGF-beta1 mRNA was recognized throughout the examination period, but there was no significant difference between xeno- and iso-grafts at most time points. These findings suggest that IFN-gamma and perforin secreted by infiltrating CD4-positive and CD8-positive T cells, respectively, play an important role in neural graft rejection. The responses of anti-inflammatory cytokines seem to be nonspecific reactions to grafts or surgical procedures.

Animals↗