Search PubMed⌕ Search

Biomedical subjects

T Imai

Publications and source records attributed to T Imai.

At least 523 records · Page 29Linked to original sources
PubMed1994

Gastric and small intestinal lesions after partial stomach resection with Billroth II or Roux-en-Y reconstruction in the rat.

The evolution and phenotypic expression of mucosal lesions of the gastric stump were investigated in male rats submitted to gastric resection with reconstruction by the Billroth II technique (BII with biliopancreatic reflux, BPR) or by the Roux-en-Y procedure (without BPR). Animals were studied at 24, 36, 54 and 64 weeks after surgery and the phenotypic expression of lesions analysed using routine hematoxylin and eosin staining, immunohistochemical staining for pepsinogen isoenzyme 1 and histochemical procedures for mucins (paradoxical concanavalin A, galactose oxidase Schiff (GOS) and sialidase GOS reactions). BPR was found to be responsible for the formation of adenomatous hyperplasia (AH), increasing in incidence and size with time, since the Roux-en-Y procedure failed to induce the gastric stump lesions observed after BII reconstruction. AHs always occurred in the transition of the gastrojejunal junction, a site offering special conditions for BPR influence, and were classified as gastric (G), intestinal (I) and G+I types according to their phenotypic expression. No pure I type AH was diagnosed at any time point. The G and G+I types developed at approximately equal incidences (i.e., G type 7/17, G+I type 10/17 at the 64th week). It was suggested that both gastric and intestinal mucosal elements were stimulated to proliferate by BPR, with the gastric mucosa tending to demonstrate AH. Intestinal type components of AH were found adjacent to the jejunum and not at the stomach margin, indicating an origin from intestinal mucosa. No metaplasia of the gastric mucosa was observed in any animal after partial gastric resection. In 101 rats submitted to the BII procedure, 5 mucinous adenocarcinomas were eventually diagnosed, mostly located in the subserosa of the gastrojejunal junction. All carcinomas expressed the phenotype of cells of the small intestine. Evidence of malignant transformation within the gastric components of AH was not observed even at the 64th week. In conclusion, all lesions induced by BPR in the rat remnant stomach are benign, and the few true cancers that arise in association are derived from the small intestine.

Animals↗
PubMed1994

Recent translocation of variable and diversity segments of the human immunoglobulin heavy chain from chromosome 14 to chromosomes 15 and 16.

We studied the organization and origin of three orphon regions, VH-F, D5-a, and D5-b, of the human immunoglobulin heavy-chain gene using yeast artificial chromosomes. VH-F and two D5 regions were mapped to chromosome bands 16p11 and 15q11-q12, respectively, by using human/rodent somatic cell hybrids and fluorescence in situ hybridization. No D5 segments were found on chromosome 14, in contradiction to previous reports. The VH-F region consists of 7 VH segments and encompasses 160 kb of DNA. A cluster of VH segments homologous to the VH-F region orphons was found in the region 245-430 kb (V2-26 to V3-11) upstream of the JH cluster on chromosome 14. Comparison of VH sequences between the VH-F and the chromosome 14 loci indicates that the translocation of the VH-F region took place, at the earliest, 20 x 10(6) years ago. The D5-a and D5-b regions were obtained in two independent contigs. The former contains only D segments in 140 kb of DNA, while the latter carries 3 VH segments downstream of D segments in 110 kb of DNA. V54, one of these VH orphon segments, is about 95% homologous to V1-18, which is located within the putative ancestor of the VH-F region on chromosome 14. Furthermore, the region detected by two DNA probes flanking the V54 segment was found only in the proximity of V1-18 within the 0.8-Mb VH region on chromosome 14. These results suggest that the two orphon loci on chromosomes 15 and 16 may have been translocated simultaneously.

Animals↗
PubMed1994

Efficacy of inhaled nitric oxide in a porcine model of adult respiratory distress syndrome.

OBJECTIVE: To assess the efficacy of inhaled nitric oxide (NO) in reducing pulmonary hypertension in a porcine model of adult respiratory distress syndrome. DESIGN: Nonrandomized, controlled experiment without blinding. SETTING: Surgical research laboratory. PARTICIPANTS: Twelve pigs, matched equally for body weight. INTERVENTION: Acute lung injury was induced by intravenous injection of oleic acid. Animals were then divided into either a control group, for monitoring without any further intervention, or a NO-treatment group, in which NO was administered at concentrations of 10 to 80 ppm, with each step separated by a NO-free interval to assess duration of effect. MAIN OUTCOME MEASURES: Pulmonary artery pressure, systemic blood pressure, PaO2, intrapulmonary shunt fraction, and extravascular lung water. Nitrosylated hemoglobin, arterial methemoglobin, and plasma nitrite and nitrate concentrations. RESULTS: All animals responded to oleic acid injection with rapid development of pulmonary hypertension and deterioration of PaO2 and intrapulmonary shunt fraction. Inhaled NO reversed these changes in a concentration-dependent manner. Cessation of NO administration led to a prompt return of pulmonary hypertension. A small but significant drop in systemic blood pressure was observed only at the highest concentration of NO administered (80 ppm). Extravascular lung water almost doubled following oleic acid injury. This increase was sustained in all animals for the remainder of the experiment. Significant increases in circulating methemoglobin and plasma nitrite and nitrate concentrations were measured during NO inhalation. CONCLUSION: Inhaled NO appears to be a selective pulmonary vasodilator and may prove to be useful in improving gas exchange in adult respiratory distress syndrome.

Administration, Inhalation↗
PubMed1994

Stereoselective hydrolysis of O-isovaleryl propranolol and its influence on the clearance of propranolol after oral administration.

The stereoselective hydrolysis of O-isovaleryl propranolol (isovaleryl-PL) was studied using phosphate and Tris-HCl buffers (pH 7.4), dog plasma, and liver preparations. The 10000g supernatant, microsomes, and cytosol were prepared from the liver homogenate. The hydrolysis rate of isovaleryl-PL was accelerated in the order Tris buffer < plasma = phosphate buffer << 10000g supernatant of liver = liver cytosol < liver microsomes. The high plasma protein binding of the prodrug brought about the extremely slow hydrolysis rate of isovaleryl-PL in plasma. No difference was observed in the hydrolysis rate between the isomers of isovaleryl-PL in buffers. The hydrolysis rate was 2-3 times faster with the (R)-isomer than with the (S)-isomer using racemate in dog plasma and liver preparations. The hydrolysis of each enantiomer was inhibited by the other enantiomer. For hydrolysis in microsomes the Km values of (R)- and (S)-isomers were same, and the Vmax of the (R)-isomer was 3 times greater than that of the (S)-isomer. These data suggested the mutual interaction of (R)- and (S)-isomers during the hydrolysis process and the rapid hydrolysis of isovaleryl-PL in liver after absorption. The AUC of PL enantiomers after oral administration of racemic isovaleryl-PL was about 2 times higher compared to 2 mg/kg equivalent molar dose of racemic PL in beagle dogs, and the corresponding plasma levels were not stereoselective from both PL and prodrug. The amount of (R)-PL absorbed after administration of a 5 mg/kg dose of racemic PL was 2-fold greater than (S)-PL, because of the stereoselective oxidation and glucronidation of (S)-PL.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1994

Discrepancy between PNMT presence and relative lack of adrenaline production in extra-adrenal pheochromocytoma.

Among catecholamine synthesizing enzymes, phenylethanolamine-N-methyltransferase (PNMT) exists only in adrenal and extra-adrenal pheochromocytoma has been believed not to produce adrenaline. However, adrenaline production is clinically active in some extra-adrenal cases. To investigate this controversy, the localization of catecholamine synthesizing enzymes was studied by immunohistochemical staining in extra-adrenal and adrenal cases. The results showed that PNMT was expressed not only in many cases of adrenal pheochromocytoma, but also in extra-adrenal pheochromocytoma. It is suspected that little adrenaline production in extra-adrenal cases is attributable to a lack of a good environment for the activation of PNMT by a high concentration of glucocorticoids.

Adrenal Gland Neoplasms↗
PubMed1994

Mouse homologue of C33 antigen (CD82), a member of the transmembrane 4 superfamily: complementary DNA, genomic structure, and expression.

C33 Ag (CD82) is a member of the transmembrane 4 superfamily (TM4SF) and an activation Ag of T-cells. Recent studies have shown that CD82 associates with CD4 or CD8 and delivers costimulatory signals for the TCR/CD3 pathway. We have isolated cDNA and genomic clones of mouse CD82. Mouse CD82 has 266 amino acid residues with 76% identity to human CD82. The mouse CD82 gene consists of nine exons and spans more than 20 kb of genomic DNA. The genomic organization of CD82 is quite similar to that of three other TM4SF members whose genomic structures were described, i.e., Tapa-1 (CD81), CD53, and CD63. By mapping the 5' end of CD82 transcripts, we found a single major transcription initiation site 144 bp upstream of the ATG initiation codon. We also determined the sequence of the 5' flanking region of CD82 gene for about 2 kb. The 5' flanking sequence has a housekeeping promoter with potential binding motifs for various transcriptional factors. Northern blot analysis showed quite variable expression of the CD82 gene among different organs. The highest expression was seen in the spleen and the kidney. The expression was low in skeletal muscle and hardly detectable in the heart. Northern blot analysis was also carried out for CD81, CD53, and CD63. The expression of the CD81 gene was ubiquitous and similar among different organs, while that of CD53 was seen only in the spleen. The expression of the CD63 gene was ubiquitous, with the highest expression in the kidney. These results together with the comparison of the structures of 5' flanking sequences of these genes indicate distinct regulations of gene expression for these four members of TM4SF.

Amino Acid Sequence↗
PubMed1994

Genetic linkage analyses of Romano-Ward syndrome (RWS) in 13 Japanese families.

Romano-Ward syndrome (RWS) is an autosomal dominant disorder characterized by prolongation of the electrocardiographic QT interval, with clinical manifestations that include recurrent syncope and sudden death from ventricular arrhythmias. Presymptomatic diagnosis is difficult because of the variability in these signs among carriers, but it is important for clinical management to prevent sudden cardiac death. To find an LQT (long QT) locus in Japanese patients and to identify DNA markers useful for presymptomatic diagnosis, linkage analyses were undertaken in 13 Japanese families with RWS patients by means of two DNA markers located on 11p15.5. One of these marker loci, HRAS, was previously reported to be tightly linked to the LQT locus in another ethnic group. Our analyses of homogeneity suggest evidence for genetic heterogeneity of RWS within the Japanese population.

Adult↗
PubMed1994

Cloning of a new kinesin-related gene located at the centromeric end of the human MHC region.

We previously reported the presence of a new gene (HSET) with an unknown function, in the centromeric side of the class II gene region of the human major histocompatibility complex (MHC). cDNA clones corresponding to the HSET gene were isolated from a human testis cDNA library. A 2.4 kilobase transcript from the HSET gene was abundantly expressed in testis, B-cell, T-cell, and ovary cell lines but was not detected in lung or stomach. Analysis of the nucleotide sequence of the HSET cDNA clones revealed significant similarity to kinesin-related proteins in yeast, Drosophila, and human. Its predicted amino acid sequence contains a domain with strong sequence similarity to the ATP-binding and motor domains of a plus end-directed microtubule motor protein, kinesin, which might be involved in mitotic chromosome segregation, suggesting that the HSET gene encodes a novel kinesin-related protein.

Amino Acid Sequence↗
PubMed1994

Surgical treatment of hepatocellular carcinoma.

The effect of surgical treatment for hepatocellular carcinoma (HCC) was evaluated in 149 resected cases, 83.2% of which were associated with liver cirrhosis. The 3- and 5-year survival rates were 60.1% and 39.4%, respectively. The mortality rate was 4.1%. In patients aged over 70 years, liver cirrhosis was found in 53.3% of cases and the mortality rate was 6.7%. The 3- and 5-year survival rates were 50.8% and 33.9%, respectively. Factors that significantly affected survival for more than 5 years were a tumor size of less than 3 cm, Stage I disease, vp(-), IMo, and diploid type. The 5-year survival rate for patients with a single tumor of 3 cm or less was 54.2%, regardless of the surgical procedure. All 15 patients with a solitary tumor of 2 cm or less (Stage I, small liver tumor) were alive with a 5-year survival rate of 100%. The problem is the treatment of patients with a tumor measuring 3-5 cm in diameter and associated liver cirrhosis, because their prognosis after surgery is the worst. HrS (subsegmentectomy) is the minimal procedure of limited hepatectomy for these cases with postoperative multidisciplinary therapy.

Adult↗
PubMed1994

Synaptic pathology of spinal anterior horn cells in amyotrophic lateral sclerosis: an immunohistochemical study.

We have applied immunohistochemical techniques to study synaptic alterations of the spinal anterior horn in amyotrophic lateral sclerosis (ALS), and other disorders involving upper or lower motor neurons. A monoclonal antibody to synaptophysin was used. Spinal cord tissues from normal individuals served as controls. As compared to these, a decrease in synaptophysin immunoreactivity was evident in the neuropil in the spinal anterior horn of ALS patients. However, synaptophysin expression in the perikarya and dendrites of remaining normal-appearing neurons in these patients was not decreased and occasionally it was even higher than in control neurons. Similar results were obtained with specimens from patients with lower motor neuron disease. Synaptophysin immunoreactivity in the neuropil and perikarya of the cases with focal spinal cord lesions with bilateral descending tract degeneration was similar to normal controls. Our data suggest that the alterations in synaptophysin expression occurring in ALS are mainly associated with the loss of lower motor neurons, and that the occasional increased perikaryal expression may be due to the neuronal atrophy, compensatory accumulation or abnormal synaptic vesicle degradation.

Aged↗
PubMed1994

Experience with 17 cases of laparoscopic adrenalectomy: use of ultrasonic aspirator and argon beam coagulator.

Between January 17, 1992 and July 31, 1993, 11 patients with primary aldosteronism, 3 with Cushing's syndrome and 3 with a nonfunctioning adrenal tumor underwent laparoscopic adrenalectomy at our university hospital. In every patient adrenal tumor was removed successfully with adjacent normal adrenal tissue. The initial 10 operations were performed without use of an ultrasonic aspirator or argon beam coagulator, and the subsequent 7 procedures were done with those items. There was no difference between the groups in intraoperative blood loss or operative time. However, the tumors in the former group were significantly smaller than those of the latter group (mean 6.70 gm. versus 13.43 gm., respectively, p < 0.05, t test). For right tumors the argon beam coagulator was useful to resect or coagulate the liver, since adrenal tumors were sometimes tightly attached to the liver and upward retraction sometimes caused liver laceration. In obese patients or those with Cushing's syndrome the ultrasonic aspirator was useful to remove retroperitoneal fat surrounding the adrenal tumor without injury to the small vessels. The mean hospital stay for these 17 patients (11.63 days) was significantly shorter than that of 16 patients with corresponding adrenal tumors undergoing open removal during the last 5 years (17.32 days, p < 0.05 t test). In conclusion, laparoscopic adrenalectomy is feasible for the surgical treatment of primary aldosteronism, Cushing's syndrome and nonfunctioning adrenal tumors. The ultrasonic aspirator and argon beam coagulator may be useful for laparoscopic adrenalectomy.

Adrenal Gland Neoplasms↗
PubMed1994

The controlled release of prednisolone using alginate gel.

In a release study of alginate gel beads, swelling and erosion of the beads were observed at pH 6.8, whereas no swelling occurred at pH 1.2. The amount of released prednisolone (PL) was greater at pH 6.8 than at pH 1.2. The lower the ratio of mannuronic acid block to guluronic acid block in alginate, the slower the release of PL. An increase in loaded PL in the beads resulted in a slower release of PL. The decrease in bead size caused a rapid release of PL. The addition of sodium alginate propylene glycol ester elevated the extent of PL release. The plasma profile of PL showed sustained-release behavior after the oral administration of the beads to beagles. Furthermore, the correlation between in vitro release and in vivo absorption of PL for various alginate gel beads was evaluated using deconvolution and convolution methods. The in vivo absorption of PL was correlated with the PL release at pH 1.2, and it differed from that at pH 6.8. The release of PL from alginate gel beads in vivo appeared to occur under conditions that cause little swelling.

Absorption↗
PubMed1994

Isolation and characterization of a novel gene encoding nuclear protein at a locus (D11S636) tightly linked to multiple endocrine neoplasia type 1 (MEN1).

To identify a gene responsible for multiple endocrine neoplasia type 1 (MEN1), we attempted to isolate potentially transcribable fragments from cosmid clones derived from a region on chromosome 11q13 where genetic linkage studies and analyses of loss of heterozygosity in MEN1-associated tumors have localized the MEN1 gene. By an exon-amplification method, we recovered three exon-like sequences from one of these clones, cCI11-367, and using these sequences as probes we were able to isolate new clones from cerebrum, cerebellum, and fetal-liver cDNA libraries. Sequence analysis of these cDNA clones revealed that the transcribed gene, designated ZFM1, encodes a novel 623-amino-acid protein containing domains with interesting structural properties including a nuclear transport domain, a metal binding motif, and glutamine- and proline-rich regions. Analysis by the reverse-transcriptase polymerase chain reaction (RT-PCR) indicated that this gene is expressed in various tissues including endocrine organs such as thyroid gland, pancreas, adrenal gland, and ovary. These data suggest that ZFM1 might be a candidate for mutations that cause MEN1.

Amino Acid Sequence↗
PubMed1994

Factor-XIIIa-positive cells in normal peripheral nerves and cutaneous neurofibromas of type-1 neurofibromatosis.

Cutaneous neurofibromas consist of heterogenous cell populations including Schwann cells, perineurial cells, and fibroblastlike cells. However, the histogenesis of neurofibromas, particularly the origin and nature of the fibroblastlike cells, is still controversial. Recently, cells containing blood coagulation factor XIIIa have been reported in cutaneous neurofibromas, although their identity is uncertain. In this report, by the combination of double immunohistochemical staining and immunoelectron microscopy, we demonstrate that factor-XIIIa-positive cells are distinct from Schwann cells, perineurial cells, endothelial cells, mast cells, and conventional macrophages, but correspond to the fibroblastlike cells in cutaneous neurofibromas. Such factor-XIIIa-positive cells in cutaneous neurofibromas, however, differ from conventional fibroblasts in the strong expression of HLA-DR antigen and lack of prolyl 4-hydroxylase. Similarly, so-called endoneurial fibroblasts and, occasionally, connective tissue cells within perineurium and epineurium in normal peripheral nerve fibers express factor XIIIa as well as HLA-DR antigen. The results suggest that fibroblastlike cells in cutaneous neurofibromas are probably derived from factor-XIIIa- and HLA-DR antigen-positive connective tissue cells in peripheral nerves. The role of such factor-XIIIa-positive cells in the growth and development of cutaneous neurofibromas is discussed.

Actins↗
PubMed1994

An adult case of histiocytosis X with a vulvar ulcer and multiple bone lesions.

A 62-year-old female with histiocytosis X presented with a vulvar ulcer. Multiple osteolytic lesions were later detected. Histological examination of the ulcerated skin showed diffuse proliferation of histiocytic cells with folded nuclei and pale eosinophilic cytoplasm. Immunohistochemistry revealed S100 protein and vimentin as well as CD1a, CD4, and HLA-DR antigens in the proliferating cells. Electron microscopy demonstrated Birbeck granules in the cytoplasm of the cells. The patient was successfully treated by complete surgical excision of the ulcer followed by radiotherapy for recurrent vulvar erythema.

Female↗