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Biomedical subjects

T Chiba

Publications and source records attributed to T Chiba.

At least 235 records · Page 13Linked to original sources

Using helical CT to evaluate renal cell carcinoma in patients undergoing hemodialysis: value of early enhanced images.

OBJECTIVE: The purpose of this study was to evaluate early and delayed enhanced helical CT for revealing renal cell carcinoma in patients undergoing hemodialysis. MATERIALS AND METHODS: Over the course of 3 years, 630 chronic hemodialysis patients underwent early and delayed contrast-enhanced and unenhanced helical CT to detect renal cell carcinoma. Retrospective review showed that 23 of these patients later underwent either unilateral or bilateral nephrectomy. Two radiologists, unaware of the pathology results, independently reviewed these 23 examinations. The sensitivity and specificity of each early and delayed scan for revealing neoplasms were determined using pathology as the gold standard. The mean attenuation values of the neoplasms and parenchymas of end-stage kidneys on both early and delayed enhanced images were also compared. RESULTS: Helical CT revealed 225 lesions, 24 of which were found to be renal cell carcinomas at pathology. Delayed enhanced helical CT failed to detect one papillary carcinoma in an end-stage kidney with acquired cysts. Three nonpapillary carcinomas were not detected on delayed scans, and one was missed on an early scan of a patient without acquired cysts. The sensitivity and specificity of early enhanced CT for revealing renal cell carcinoma were 96% and 95%, respectively. In contrast, delayed enhanced CT achieved a sensitivity of 83% and a specificity of 94%. A significant difference in mean attenuation values between carcinomas and renal parenchymas was observed on the images with early enhancement but not on those with delayed enhancement (p < .0001). CONCLUSION: Early enhanced helical CT is superior to delayed enhanced helical CT for revealing renal cell carcinoma in end-stage kidneys.

Carcinoma, Renal Cell↗

Ultrasonographic arterial portography with second harmonic imaging: evaluation of hepatic parenchymal enhancement with portal venous flow.

Ultrasonographic arterial portography was evaluated with second harmonic and conventional gray scale imaging after the administration of 0.001 to 0.1 ml/kg of FS069 (Optison) in 10 dogs (four dogs with ligation of the portal vein branch) and two woodchucks with hepatocellular carcinomas. Harmonic imaging was required to obtain good liver parenchymal enhancement for ultrasonographic arterial portography to be useful. The tumors were visible as regions of greater enhancement after intravenous injection and as hypoechoic regions after superior mesenteric artery injection. The segments with portal vein ligation were not detected after intravenous injection but were clearly seen after superior mesenteric artery injection. Doppler signal measurement verified a significant difference between the portal vein and hepatic vein after superior mesenteric artery injection and in the femoral artery after intravenous versus superior mesenteric artery injection, demonstrating that minimal levels of FS069 pass through the liver.

Albumins↗

[Advances in endoscopic therapies for cancers of the digestive tract].

Endoscopic therapies for the treatment of cancers of the digestive tract have been improved. Today, some early cancers can be curatively treated by endoscopy (endoscopic polypectomy, endoscopic mucosal resection, heatprobe method, etc.). In addition, endoscopic local injection chemotherapy is performed for some advanced cancers as an adjuvant therapy. Recent progress in endoscopic therapies for cancer is reviewed in this paper, including their historical background. Improvements in these endoscopic treatment methods are expected to provide increased advantages for the treatment of patients with cancer in the near future.

Colonic Polyps↗

Hyperfunctional parathyroid glands with 99mTc-MIBI scan: semiquantitative analysis correlated with histologic findings.

UNLABELLED: The purpose of this study was to correlate the semiquantitative analysis of 99mTc-methoxyisobutyl isonitrile (MIBI) scan with histologic findings of hyperfunctional parathyroid glands. METHODS: Early and delayed cervical images of MIBI scans were reviewed in 31 patients who eventually underwent parathyroidectomies because of biochemically suspected hyperparathyroidism ([HPT], primary, n = 13; secondary, n = 18). The sensitivity of a scan for localizing the diseased glands was determined by comparing scan findings with pathologic findings, which were considered the gold standard. The average ratio of parathyroid-to-thyroid (P/T) count was compared between glands with large and small areas of whole gland, chief cell, oxyphil cell or cellular components. The mean areas of whole gland, chief cells and oxyphil cells were also compared between glands detected by MIBI scan and those that the scan missed. RESULTS: There were 99 resected lesions, including 9 parathyroid adenomas and 61 hyperplastic parathyroids. The sensitivity for localizing the diseased glands in patients with primary HPT (91%) was higher than that in patients with secondary HPT (83%). Significantly greater average P/T counts ratio on both early and delayed images was observed in the diseased glands with greater areas of whole gland, chief cells, oxyphil cells or cellular components. Fifty-nine MIBI-positive glands had significantly greater average areas of whole gland (P < 0.001) and chief cell (P = 0.002) than did 11 MIBI-negative glands. CONCLUSION: The uptake of MIBI in hyperfunctional parathyroid is dependent on gland size and the amount of cellular components, chief cells and oxyphil cells. However, the amount of oxyphil cells does not clearly affect the results of MIBI parathyroid scintigraphy, because it is small in most hyperfunctional glands.

Adenoma↗

Light-induced apoptosis in the neonatal mouse retina and superior colliculus.

UNLABELLED: PURPOSE. Apoptosis occurs naturally in the rodent retina and superior colliculus (SC) during the neonatal period. The authors used mice to demonstrate the dependency of this apoptosis on the light stimulation and the developmental period. METHODS: A number of apoptotic cells were counted in the retina and SC from a group of newborn mice reared in constant darkness (DD group), a group reared in normal light and dark conditions (LD group), and a group reared in constant darkness up to P7 and then transferred to normal condition (DD-to-LD group). Terminal deoxynucleotidyl transferase-mediated biotin-dUTP nick end labeling (TUNEL) was used for visualization of the apoptotic cells. RESULTS: In the LD group, apoptotic cells significantly increased in the retinal nuclear layers, including both the outer and inner nuclear layers, the retinal ganglion cell layer, and SC at postnatal day 1 (P1) and postnatal day 2 (P2). The number of apoptotic cells in the ganglion cell layer and SC reached the maximum level at P1. In contrast, in the DD group, an increase in the number of apoptotic cells was not observed. At P9, no significant increase in the number of apoptotic cells was observed in the outer nuclear layer, ganglion cell layer, and SC either in the LD, DD, or DD-to-LD groups, but the LD and DD-to-LD groups showed a significant increase in the inner nuclear layer compared to the DD group. CONCLUSIONS: Apoptosis during the neonatal period in the mouse visual system is induced by a light stimulus. This apoptosis was not induced after P7 in the retinal ganglion cell layer and SC, even if excessive cells survived.

Animals↗

Two cases of appendicitis in Kawasaki disease.

Two cases of appendicitis in Kawasaki disease (KD) are presented. Appendicitis in KD is very rare condition, and only a few cases have been previously reported. This report suggests the need to expand the differential diagnosis of abdominal pain in this group of patients.

Acute Disease↗

The ligation systems for ubiquitin and ubiquitin-like proteins.

Ubiquitin (Ub) is a highly conserved small protein present universally in eukaryotic cells, which is covalently attached to substrate proteins by a cascade system, consisting of activating (E1), conjugating (E2), and/or ligating (E3) enzymes. The modification of cellular proteins with Ub targets them for degradation by a large multisubunit protease, called the 26S proteasome. The unexpected existence of many genes encoding E2 and E3 reveals that a number of distinct Ub-ligating pathways operate for selective proteolysis in cells, implying its involvement in divergent biologically important processes. Currently, it becomes clear that a set of novel molecules with a structural similarity to Ub, called Ub-like proteins (Ubls), is present in various eukaryotic cells. They are divided into two subclasses: type-1 Ubls with small sizes, such as SUMO1 and NEDD8, that are ligated to target proteins in a fashion similar, but not identical, to the ubiquitination pathway, and another type-2 Ubls that contain Ub-like structure in a variety of different classes of large proteins having apparently distinct functions, such as Rad23, Elongin B, and Parkin. Ub and type-1 Ubls are central players consisting of a new type of post-translational protein-modifying system, although the significance of type-2 Ubl remains obscure.

Animals↗

The vagal origin of preganglionic fibers containing nitric oxide synthase in the guinea-pig heart.

The origin of nerve fibers projecting to the guinea pig heart that contain nitric oxide synthase (NOS) were studied by unilateral cervical vagotomy. Three kinds of NOS-immunoreactive (NOS-ir) nerve fibers are distributed in the control guinea pig heart: the sparse network covering the right atrium, the basket-like endings around intracardiac neuronal cell bodies in the small ganglia located in the left atrium and the interatrial septum, and the axons situated in the septal region. The sparse network in the right atrium did not change after vagotomy of right or left side. In the whole mount preparations of right atrium, we often traced labeled axons from the somata to join the network covering the right atrium. Therefore, most of this network of labeled fibers must be of intrinsic origin. Because the basket-like endings around neuronal cell bodies in the ganglia in the left atrium and the septum disappeared completely after vagotomy of left side, we conclude that they are parasympathetic preganglionic fibers originating from the left vagus nerve. NOS-ir cell bodies and the positive fibers in the atrioventricular nodal region survived after vagotomy. All of such nerve fibers were unmyelinated axons. Therefore, they seem to be the postganglionic fibers arising from the ganglia located in the left atrium or the septum.

Animals↗

A new NEDD8-ligating system for cullin-4A.

NEDD8 is a ubiquitin (Ub)-like protein. Here we report a novel ubiquitinylation-related pathway for modification by NEDD8. NEDD8 was activated by an E1 (Ub-activating enzyme)-like complex, consisting of APP-BP1 and hUba3 with high respective homologies to the amino- and carboxy-terminal regions of E1 and then linked to hUbc12 (a human homolog of yeast Ub-conjugating enzyme Ubc12p). The major target protein modified by NEDD8 was found to be Hs-cullin-4A (Cul-4A), a member of the family of human cullin/Cdc53 proteins functioning as an essential component of a multifunctional Ub-protein ligase E3 complex that has a critical role in Ub-mediated proteolysis.

Amino Acid Sequence↗

A target specific pathway from nitric oxide synthase immunoreactive preganglionic sympathetic to superior cervical ganglion neurons innervating the submandibular salivary gland.

The correlations between nitric oxide synthase (NOS)-immunoreactive (NOS-ir) preganglionic sympathetic neurons (PSNs) in the thoracic spinal cord and the neurons in the superior cervical ganglia (SCG) were studied with special reference to target specificity. NOS-ir neurons were distributed in the intermediate gray of the spinal cord and most numerous in the intermediolateral subnucleus of the PSNs. NOS-ir PSNs received direct synaptic contacts from tyrosine hydroxylase-ir, 5-hydroxytryptamine-ir, gamma-amino butyric acid-ir, and phosphate-activated glutaminase-ir axons. A majority of PSNs projecting to SCG were NOS-ir but some were NOS-negative. Large SCG neurons surrounded by a dense network of NOS-ir axons from PSNs projected to the submandibular salivary gland. NPY-ir small SCG neurons devoid of NOS-ir PSN innervation projected to blood vessels. SIF cells in the SCG were NOS-negative and provided with a meshwork of NOS-ir axons. The present results suggest a subpopulation of SCG neurons may be concerned with a distinct functional category in the rat under the influence of NOS-ir preganglionic sympathetic neurons.

Animals↗

Efferent projections of the nucleus accumbens in the rat with special reference to subdivision of the nucleus: biotinylated dextran amine study.

The nucleus accumbens (Acb) of the rat has been divided immunohistochemically into shell and core, and further, it was subdivided into several portions in relation to functional significance. In this report, the efferent projection of each subdivision of the Acb was examined using biotinylated dextran amine as an anterograde tracer. In rostral Acb, the dorsomedial shell mainly projected to the dorsomedial ventral pallidum (VP), lateral hypothalamus (LH) and substantia nigra pars compacta (SNc), while the ventromedial shell projected to the ventromedial VP, lateral preoptic area, LH and ventral tegmental area (VTA). The dorsal core of rostral Acb projected to the caudate putamen, dorsolateral VP, globus pallidus (GP), LH, and substantia nigra pars reticulata (SNr). In the middle to caudal Acb, the dorsomedial shell mainly projected to the dorsomedial VP, LH and VTA, the ventromedial shell projected to the ventromedial VP, substantia innominata, VTA, SNc and retrorubral area, and the ventrolateral shell projected to the ventrolateral VP and SNc. Furthermore, the ventromedial shell projected to the parabrachial nucleus (PB). The dorsomedial core projected to the dorsal VP, LH, SNc and SNr, and the ventral and lateral core sent axons to the dorsolateral VP, GP and SNc. From the point of view of projection patterns, shell and core are distinct throughout the rostro-caudal extent of the Acb. The ventrolateral shell at the caudal Acb was clearly differentiated. A direct projection from the ventromedial shell of the Acb to PB was also recognised.

Animals↗

Deficiency in protein L-isoaspartyl methyltransferase results in a fatal progressive epilepsy.

Protein L-isoaspartyl methyltransferase (PIMT) is suggested to play a role in the repair of aged protein spontaneously incorporated with isoaspartyl residues. We generated PIMT-deficient mice by targeted disruption of the PIMT gene to elucidate the biological role of the gene in vivo. PIMT-deficient mice died from progressive epileptic seizures with grand mal and myoclonus between 4 and 12 weeks of age. An anticonvulsive drug, dipropylacetic acid (DPA), improved their survival but failed to cure the fatal outcome. L-Isoaspartatate, the putative substrate for PIMT, was increased ninefold in the brains of PIMT-deficient mice. The brains of PIMT-deficient mice started to enlarge after 4 weeks of age when the apical dendrites of pyramidal neurons in cerebral cortices showed aberrant arborizations with disorganized microtubules. We conclude that methylation of modified proteins with isoaspartyl residues is essential for the maintenance of a mature CNS and that a deficiency in PIMT results in fatal progressive epilepsy in mice.

Animals↗

Transmission of hepatitis B virus from hepatitis B core antibody-positive donors in living related liver transplants.

BACKGROUND: In order to clarify the risk of hepatitis B virus (HBV) transmission from hepatitis B core antibody-positive (HBcAb(+)) donors and to evolve a new strategy to counter such a risk, we undertook a retrospective (1990-1995) and prospective (1995-1996) analysis of our experience with living related liver transplantation involving HBcAb(+) donors. METHODS: Between June 15, 1990, and June 30, 1995, HBcAb(+) individuals were not excluded as donor candidates at our institutions. For 171 liver transplants, 16 donors were HBcAb(+). Between July 1, 1995, and June 30, 1996, HBcAb(+) individuals were generally excluded as donor candidates; however, three recipients were given liver grafts from HBcAb(+) donors because other donor candidates presented even higher risks. In the latter period, recipients with transplants from HBcAb(+) donors underwent prophylactic passive immunization with hyperimmune hepatitis B immunoglobulin (HBIG). The serum of 10 HBcAb(+) donors was examined by nested polymerase chain reaction for the presence of HBV-DNA, but it was not detected in any of them. However, the same examination of the liver tissue of five such donors yielded positive results in all cases. RESULTS: In the first 5-year period, out of 16 recipients with HBcAb(+) donors, 15 became hepatitis B surface antigen-positive after transplant. The three recipients with HBcAb(+) donors during the second 1-year period, who were treated by prophylactic passive immunization with HBIG, remained hepatitis B surface antigen-negative and negative for serum HBV-DNA after transplant. CONCLUSIONS: HBV exists in the liver of healthy HBcAb(+) individuals, but not in the blood. Therefore, HBV is thought to be transmitted to recipients by liver grafts from the HBcAb(+) donors at a significantly high rate. The prevention of viral activation and clinical disease development by means of passive immunization with HBIG seems promising, although the follow-up period in our study may be too short for any definitive conclusions.

DNA, Viral↗

Percutaneous autotransplantation of parathyroid tissue into the forearm muscles.

We developed a simple and easy nonsurgical percutaneous method for autografting parathyroid tissue into the forearm muscles. This method was applied to 30 patients suffering from secondary hyperparathyroidism who were then refractory to medical treatment. The operative results were then compared with 16 patients who underwent treatment using Wells' method. The graft "take," judged by a significant intact parathyroid hormone (PTH) ratio (> 1.5) between grafted and nongrafted arm vein blood, was 82% for the percutaneous method group and 75% for the Wells' method group, respectively. The percentage of recurrent hyperparathyroidism necessitating a subtotal removal of the autograft was equal in the two groups. No complications were noted for either method. Wells' method can thus be replaced by this simple and easy nonoperative method.

Adult↗