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Biomedical subjects

S Tatsumi

Publications and source records attributed to S Tatsumi.

At least 19 recordsLinked to original sources
PubMed2003

Prospective randomized pilot trial of selective biliary cannulation using pancreatic guide-wire placement.

BACKGROUND AND STUDY AIMS: In difficult cases of selective bile duct cannulation, several expanded techniques are available which have only been partially evaluated in randomized studies. This study describes a prospective, randomized trial investigating a further technique for obtaining selective biliary access--pancreatic duct wire placement. PATIENTS AND METHODS: During a six-month study period, 107 consecutive patients required deep selective biliary cannulation. Accessing the bile duct using a catheter failed within 10 min in 53 of the patients, who were randomly assigned to either pre-insertion of a guide wire into the pancreatic duct or persistence with a conventional catheter. The success rate and complication rate were compared between these two groups. RESULTS: In the pancreatic duct-guide wire group (n=27), the success rate was significantly greater than in the conventional group (93% vs 58%). No pancreatitis complications occurred within either group. CONCLUSIONS: Inserting a guide wire into the pancreatic duct to facilitate deep selective bile duct cannulation is better than persisting with a conventional catheter. Further studies will be needed to confirm these results and to compare this method with other sophisticated techniques for obtaining selective access to the bile duct.

Adult↗
PubMed2000

A case report of FSH-producing nasal ectopic pituitary adenoma extending to the frontal cranial fossa.

We report the first case of an ectopic pituitary adenoma in the nasal cavity that produced follicle-stimulating hormone (FSH). A 60-year-old man complaining of left nasal bleeding had a polypoid tumor in the left nasal cavity. Findings of computed tomographic scanning and magnetic resonance imaging showed that the tumor originated from the olfactory cleft, occupied the nasal cavity, and extended to the frontal cranial fossa. Results of histologic examination suggested ectopic pituitary adenoma. Magnetic resonance imaging results showed the pituitary gland to be normal. Electron microscopy findings demonstrated a large number of secretory granules in the tumor cells that were positive for FSH on immunohistochemical analyses. Serum gonadotropin levels were normal, and no clinical signs of hypersecretory syndrome were noted. The above findings led us to establish the diagnosis of FSH-producing ectopic pituitary adenoma. The patient underwent craniofacial resection of the tumor followed by an uneventful recovery. The pathologic findings and clinical course of the case were comparable to those of FSH-producing adenomas arising from the pituitary gland.

Adenoma↗
PubMed2000

An autopsy case of a charred body which committed suicide after arson.

A severely burned body was found lying on its right side at the scene of the fire in a 2-story wooden apartment house. The presence of a ligature (an electrical cord) running horizontally around the neck aroused suspicion of arson after homicidal strangulation (murder-arson). The entire body was severely burned and partly charred. The head and neck were severely charred, and the left temporal bone had been consumed exposing the brain. Around the neck was looped an electrical cord, which ran horizontally and canted downward toward the nape, leaving a furrow resulting from the knot being tightened up. No other injuries or pathologic lesions suggestive of the cause of death were noted. No drug, poison or alcohol was detectable in the blood or urine. The peculiar method of making a noose of the ligature around the neck is called clove hitch, which makes the noose tighten further with increased load. The fallen curtain rod had a bend with an acute angle, which was considered to have been the point of suspension in hanging. In addition, a lighter was found under the corpse, which was presumably used to ignite the gasoline that the deceased sprinkled. We speculate, therefore, that the deceased hanged himself by placing the electrical cord around his neck (by clove hitch), suspending it from the curtain rod, sprinkling gasoline in his room, igniting it with a lighter, executing suicidal hanging after the start of the fire. Probably the body was wrapped in flames while dangling, then fell to the floor together with the collapsing curtain rod.

Journal Article↗
PubMed2000

Identification and functional analysis of three isoforms for the Na+-dependent phosphate co-transporter (NaPi-2) in rat kidney.

We have isolated three unique NaPi-2-related protein cDNAs (NaPi-2alpha, NaPi-2beta and NaPi-2gamma) from a rat kidney library. NaPi-2alpha cDNA encodes 337 amino acids which have high homology to the N-terminal half of NaPi-2 containing three transmembrane domains. NaPi-2beta encodes 327 amino acids which are identical to the N-terminal region of NaPi-2 containing four transmembrane domains, whereas the 146 amino acids in the C-terminal region are completely different. In contrast, NaPi-2gamma encodes 268 amino acids which are identical to the C-terminal half of NaPi-2. An analysis of phage and cosmid clones indicated that the three related proteins were produced by alternative splicing in the NaPi-2 gene. In a rabbit reticulocyte lysate system, NaPi-2alpha, beta and gamma were found to be 36, 36 and 29 kDa polypeptides, respectively. NaPi-2alpha and NaPi-2gamma were glycosylated and revealed to be 45 and 35 kDa proteins, respectively. A functional analysis demonstrated that NaPi-2gamma and alpha markedly inhibited NaPi-2 activity in Xenopus oocytes. The results suggest that these short isoforms may function as a dominant-negative inhibitor of the full-length transporter.

Animals↗
PubMed2000

[A case of isolated fourth ventricle in the early postoperative period of subarachnoid hemorrhage].

An adult case of isolated fourth ventricle which developed in the early postoperative period of SAH is reported. A 72-year-old male with Hunt & Kosnik Grade 4 subarachnoid hemorrhage (SAH) underwent emergent neck-clipping of an anterior communicating artery aneurysm along with setting of external ventricular drainage (EVD) and cisternal drainage (CD). The lamina terminalis (LT) was opened. Preoperative study had showed diffuse SAH with intraventricular hemorrhage (IVH), and mild dilatation of the whole ventricular system on CT scan (Fisher Group 4). Twelve hours after surgery, both of the drainages were opened with the pressure setting of 20 cm H2O for EVD and 10 cm H2O for CD. Although his neurological state had been improving, 2 hours after the opening of the drainages he suddenly fell into respiratory arrest and coma, when 20 ml of CFS through CD was drained. On CT scan, isolated fourth ventricle was recognized. The patient died on the ninth postoperative day. In case of severe SAH with diffuse IVH, we should be careful when setting the pressure of EVD or CD with the LT opened, because of the possibility of occlusion of the fourth ventricle outlet and aqueduct, that results in fourth ventricle isolation.

Aged↗
PubMed1999

Regulation of intestinal Na+-dependent phosphate co-transporters by a low-phosphate diet and 1,25-dihydroxyvitamin D3.

In a study of the rat intestinal P(i) transport system, an activator protein for rat Na/P(i) co-transport system (PiUS) was isolated and characterized. We also investigated the effects of restriction of vitamin D and P(i) (two of the most important physiological and pathophysiological regulators of P(i) absorption in the small intestine) on intestinal P(i) transport activity and the expression of Na/P(i) co-transporters that are expressed in rat small intestine. Rat PiUS encodes a 424-residue protein with a calculated molecular mass of 51463 Da. The microinjection of rat PiUS into Xenopus oocytes markedly stimulated Na(+)-dependent P(i) co-transport activity. In rats fed with a low-P(i) diet, Na(+)-dependent P(i) co-transport activity was increased approx. 2-fold compared with that of rats fed a normal P(i) diet. Kinetic studies demonstrated that this increased activity was due to an elevation of V(max) but not K(m). The PiUS mRNA levels showed an approximate doubling in the rats fed with the low-P(i) diet compared with those fed with the normal P(i) diet. In addition, after the administration of 1, 25-dihydroxyvitamin D(3) [1,25-(OH)(2)D(3)] to vitamin D-deficient animals, the P(i) uptake was significantly increased in the Na(+)-dependent component in the brush border membrane vesicle (BBMV) at 24 and 48 h. In addition, we found a further high-affinity Na/P(i) co-transport system in the BBMV isolated from the vitamin D-replete animals. The levels of type III Na/P(i) co-transporter PiT-2 mRNA were increased 24 and 48 h after 1,25-(OH)(2)D(3) administration to vitamin D-deficient animals, whereas PiUS and the type IIb Na/P(i) co-transporter mRNA levels were unchanged. In conclusion, we first cloned a rat activator protein, PiUS, and then studied its role along with that of other type III Na/P(i) co-transporters. PiUS and PiT-2 might be important components in the regulation of the intestinal P(i) transport system by P(i) restriction and 1,25-(OH)(2)D(3).

Amino Acid Sequence↗
PubMed1999

Presumption of a suspect based on the skin fragment attached the rope.

An eight-year-old girl (second-year of elementary school) was strangled in an irrigation canal near her house and was left unconscious. The body of a male who hanged himself to death was discovered on the next day. The hanging mark on the neck of the man and the ligature mark on the neck of the girl were caused by double nooses of a rope, the width of the rope mark was nearly the same, and similar Zwischenkammblutung (subcutaneous bleeding in the middle of the rope mark) was observed in both cases. Therefore, we evaluated whether the marks were caused by the same rope. As a result, the DNA type of the skin fragment (keratinized epithelial cells) attached to the rope used by the man to hang himself was identical to that of the girl. On the basis of this evidence, the man who hanged himself to death was presumed to be the suspect who strangled the girl.

Journal Article↗
PubMed1999

Estimation of age by epidermal image processing.

Small pieces of human precordial skin were obtained from 266 individuals during autopsy performed in Osaka Prefecture. The area from the stratum corneum to the stratum basale in a unit area of the epidermal cross-section was extracted as a segmented area of white image by image processing. The number of pixels surrounding this area was measured in individuals of various ages, and the age-associated changes were evaluated. The number of pixels around this binary image in the epidermal cross-section showed a strong correlation with age. The number tended to decrease with an increase in age in individuals aged 20 years and above, which could be closely approximated by an exponential function. A formula for estimating age was obtained as an inverse function of the number of pixels and age, and the accuracy of estimation using this formula was examined by comparing the estimated age with the actual age. Such age-associated changes in the epidermis were considered to be closely related with increased roughening of the stratum basale, flattening of dermal papillae, and a decreased percentage of the stratum granulosum per unit area of epidermis observed by light microscopy or scanning electron microscopy.

Journal Article↗
PubMed1999

Nicotinamide inhibits sodium-dependent phosphate cotransport activity in rat small intestine.

BACKGROUND: We recently reported that the administration of niceritorol (a nicotinic acid derivative which improves lipid metabolism and peripheral circulation, and is used for the treatment of hyperlipidaemia and impaired peripheral circulation) to patients with hyperphosphataemia undergoing dialysis decreased the serum phosphate (Pi) concentration. We found that this was due to an acceleration of faecal Pi excretion by niceritrol. METHODS: Intestinal brush border membrane vesicles (BBMVs) were prepared from rat jejunum, and the Na+-dependent and Na+-independent Pi transport activities in these vesicles were measured. In addition, the functional Pi transporter from rat small intestine was injected in Xenopus oocytes, and the effect of nicotinamide on the levels of its expression were measured by northern blotting. RESULTS: The Na+-dependent component was significantly decreased in the BBMVs isolated from rats treated with nicotinamide, while the Na+-independent component was not changed. Kinetic studies demonstrated that the decreased activity was due to reduction of the Vmax value and not an elevation of the Km values. When poly(A)+RNA from rats treated with nicotinamide was microinjected into Xenopus oocytes, the Pi transport activity was significantly decreased compared with that in the control animals. In addition, there were no significant changes in Na/Pi cotransporters and activators, but the vitamin D receptor mRNA level was reduced to 80% of the control level. CONCLUSIONS: These observations suggest that nicotinamide may regulate the expression of a major functional Na/Pi cotransporter in the rat small intestine.

Animals↗
PubMed1999

Regulation of PiT-1, a sodium-dependent phosphate co-transporter in rat parathyroid glands.

A cDNA encoding an Na+-Pi co-transporter, termed rat PiT-1, has now been isolated from rat parathyroid. Expression of rat PiT-1 in Xenopus oocytes revealed that it possesses Na+-dependent Pi co-transport activity. The amount of PiT-1 mRNA in the parathyroid of vitamin D-deficient rats was reduced compared with that in normal animals, and increased markedly after administration of 1,25-dihydroxyvitamin D3. Furthermore, the abundance of PiT-1 mRNA in the parathyroid was much greater in rats fed a low-Pi diet than in those fed a high-Pi diet. Thus, rat PiT-1 may contribute to the effects of Pi and vitamin D on parathyroid function.

Animals↗
PubMed1998

Identification of three isoforms for the Na+-dependent phosphate cotransporter (NaPi-2) in rat kidney.

We have isolated three unique NaPi-2-related protein cDNAs (NaPi-2alpha, NaPi-2beta, and NaPi-2gamma) from a rat kidney library. NaPi-2alpha cDNA encodes 337 amino acids which have high homology to the N-terminal half of NaPi-2 containing 3 transmembrane domains. NaPi-2beta encodes 327 amino acids which are identical to the N-terminal region of NaPi-2 containing 4 transmembrane domains, whereas the 146 amino acids in the C-terminal region are completely different. In contrast, NaPi-2gamma encodes 268 amino acids which are identical to the C-terminal half of NaPi-2. An analysis of phage and cosmid clones indicated that the three related proteins were produced by alternative splicing in the NaPi-2 gene. In a rabbit reticulocyte lysate system, NaPi-2 alpha, beta, and gamma were found to be 36, 36, and 29 kDa amino acid polypeptides, respectively. NaPi-2alpha and NaPi-2gamma were glycosylated and revealed to be 45- and 35-kDa proteins, respectively. In isolated brush-border membrane vesicles, an N-terminal antibody was reacted with 45- and 40-kDa, and a C-terminal antibody was reacted with 37-kDa protein. The sizes of these proteins corresponded to those in glycosylated forms. A functional analysis demonstrated that NaPi-2gamma and -2alpha markedly inhibited NaPi-2 activity in Xenopus oocytes. The results suggest that these short isoforms may function as a dominant negative inhibitor of the full-length transporter.

Amino Acid Sequence↗
PubMed1998

Effects of dietary Pi on the renal Na+-dependent Pi transporter NaPi-2 in thyroparathyroidectomized rats.

Dietary Pi and parathyroid hormone (PTH) are two most important physiological and pathophysiological regulators of Pi re-absorption in the renal proximal tubule. Effects of dietary Pi on Na+/Pi co-transporter NaPi-2 were investigated in thyroparathyroidectomized (TPTX) rats. NaPi-2 protein and mRNA in the kidney cortex of TPTX rats were increased approximately 3.8- and 2.4-fold in amount respectively compared with those in the sham-operated animals. Administration of PTH to the TPTX rats resulted in a decrease in the amount of NaPi-2 protein, but not in the abundance of NaPi-2 mRNA. Deprivation of dietary Pi in the TPTX rats did not affect the amount of NaPi-2 mRNA and protein. In the Pi-deprived TPTX rats, feeding of a high-Pi diet resulted in marked decreases in Pi transport activity and the amount of NaPi-2 protein in the superficial nephrons. Immunohistochemical analysis demonstrated that administration of PTH to TPTX rats resulted in a decrease in NaPi-2 immunoreactivity from both superficial and juxtamedullary nephrons within 4 h. Switching TPTX animals from a low-Pi diet to the high-Pi diet decreased NaPi-2 immunoreactivity from superficial nephrons, but not from juxtamedullary nephrons, within 4 h. These results suggest that dietary Pi could regulate the amount of NaPi-2 protein in the superficial nephrons in a PTH-independent manner.

Animals↗
PubMed1998

Regulation of type II renal Na+-dependent inorganic phosphate transporters by 1,25-dihydroxyvitamin D3. Identification of a vitamin D-responsive element in the human NAPi-3 gene.

Vitamin D is an important regulator of phosphate homeostasis. The effects of vitamin D on the expression of renal Na+-dependent inorganic phosphate (Pi) transporters (types I and II) were investigated. In vitamin D-deficient rats, the amounts of type II Na+-dependent Pi transporter (NaPi-2) protein and mRNA were decreased in the juxtamedullary kidney cortex, but not in the superficial cortex, compared with control rats. The administration of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) to vitamin D-deficient rats increased the initial rate of Pi uptake as well as the amounts of NaPi-2 mRNA and protein in the juxtamedullary cortex. The transcriptional activity of a luciferase reporter plasmid containing the promoter region of the human type II Na+-dependent Pi transporter NaPi-3 gene was increased markedly by 1,25-(OH)2D3 in COS-7 cells expressing the human vitamin D receptor. A deletion and mutation analysis of the NaPi-3 gene promoter identified the vitamin D-responsive element as the sequence 5'-GGGGCAGCAAGGGCA-3' nucleotides -1977 to -1963 relative to the transcription start site. This element bound a heterodimer of the vitamin D receptor and retinoid X receptor, and it enhanced the basal transcriptional activity of the promoter of the herpes simplex virus thymidine kinase gene in an orientation-independent manner. Thus, one mechanism by which vitamin D regulates Pi homeostasis is through the modulation of the expression of type II Na+-dependent Pi transporter genes in the juxtamedullary kidney cortex.

Animals↗
PubMed1998

Characterization of the 5' flanking region of the human NPT-1 Na+/phosphate cotransporter gene.

To elucidate the expression and regulation of the human type I Na+/phosphate transporter gene (NPT-1), the 5' flanking region of the NPT-1 gene was cloned, and its nucleotide sequence and function were determined. A genomic clone that contained approximately 14.0 kb of the 5'-flanking region of the NPT-1 gene was isolated. A single transcription start site was located 104 base pairs (bp) upstream of the 3' end of exon 1. In addition to the sequence of the 5'-flanking region contained a sequence weakly homologous to a TATA box at position -41 to -36 and many transcriptional regulatory elements. Transient expression revealed that a 45-bp region of proximal to exon 1, which contained TATA-like sequence, was sufficient for promoting luciferase expression in OK-cells derived from opossum kidney proximal tubule.

Carrier Proteins↗
PubMed1998

A novel Na+/Ca2+ channel blocker, NS-7, suppresses hypoxic injury in rat cerebrocortical slices.

The substance 4-(4-fluorophenyl)-2-methyl-6-(5-piperidinopentyloxy) pyrimidine hydrochloride (NS-7) has been developed recently as a cerebroprotective compound with Na+ and Ca2+ channel blocking action. In the present study, the effect of NS-7 in an in vitro model of hypoxic injury was examined and the possible involvement of Na+ and Ca2+ channels in the hypoxic injury subsequently determined. When slices of rat cerebral cortex were exposed to hypoxia/glucose deprivation followed by reoxygenation and restoration of the glucose supply, marked leakage of lactate dehydrogenase (LDH) occurred 3-6 h after reoxygenation. This hypoxia/reoxygenation-induced injury was blocked almost completely by the removal of extracellular Ca2+ or by chelating intracellular Ca2+ with 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl)ester (BAPTA/AM). In addition, combined treatment with the N-type Ca2+ channel blocker omega-conotoxin GVIA and the P/Q-type Ca2+ channel blocker omega-agatoxin IVA significantly reduced LDH leakage, although neither of these Ca2+ channel blockers alone, nor nimodipine, an L-type Ca2+ channel blocker, was effective. On the other hand, several Na+ channel blockers, including tetrodotoxin, local anaesthetics and antiepileptics, significantly reduced the hypoxic injury. NS-7 (3-30 microM) concentration-dependently inhibited LDH leakage caused by hypoxia/reoxygenation, but had no influence on the reduction of tissue ATP content and energy charge during hypoxia and glucose deprivation. It is suggested that blockade of Na+ and Ca2+ channels is implicated in the cerebroprotective action of NS-7.

Adenosine Triphosphate↗
PubMed1998

Inhibition of depolarization-induced nitric oxide synthase activation by NS-7, a phenylpyrimidine derivative, in primary neuronal culture.

Neuronal nitric oxide synthase (NOS) is considered to be involved in the pathogenesis of ischemic brain damage. In the present study, the effect of a novel neuroprotective phenylpyrimidine derivative, 4-(4-fluorophenyl)-2-methyl-6-(5-piperidinopentyloxy)pyrimidine hydrochloride (NS-7), on depolarization-stimulated NOS activity was examined in cultured neurons of mouse cerebral cortex. Various depolarizing stimuli such as veratridine, KCl, and N-methyl-D-aspartate increased the NOS activity determined by cyclic GMP formation. NS-7 concentration-dependently inhibited both the veratridine- and KCl-induced NOS activation with IC50 values of 9.3 and 9.6 microM, respectively. The reversal of KCl-evoked NOS activity by NS-7 was also observed under blockade of both ionotropic glutamate receptors and the Na+ channel with MK-801, 6-cyano-7-nitroquinoxaline-2,3-dione, and tetrodotoxin. In contrast, NS-7, even at 100 microM, did not affect N-methyl-D-aspartate-stimulated NOS activity, nor did it have any influence on NOS activity determined in the soluble fraction of rat hippocampus. Because NS-7 has already been shown to block both Na+ and Ca2+ channels, the present findings suggest that this compound inhibits depolarization-induced NOS activation by reducing Ca2+ influx through blockade of Na+ and Ca2+ channels in primary neuronal culture.

Animals↗