Biomedical subjects

R Imai

Publications and source records attributed to R Imai.

At least 19 recordsLinked to original sources

PubMed2006

Insulin resistance and impaired myocardial fatty acid metabolism in dialysis patients with normal coronary arteries.

We investigated whether insulin resistance is associated with impaired cardiac fatty acid metabolism in maintenance hemodialysis patients without coronary artery disease. We studied 55 nondiabetic (63+/-11 years old) and 51 diabetic (61+/-10 years old) hemodialysis patients with normal coronary arteries, using single-photon emission computed tomography (SPECT) with an iodinated fatty acid analogue, iodine-123-beta-methyl iodophenyl-pentadecanoic acid ((123)I-BMIPP), to evaluate cardiac fatty acid metabolism. SPECT imaging was graded regionally from 0 (normal) to 4 (absence of tracer) to calculate a summed score for 17 left ventricular segments. Insulin resistance was determined using the homeostasis model assessment index of insulin resistance (HOMA-IR). HOMA-IR correlated with summed BMIPP score in nondiabetic and diabetic patients. Stepwise multiple regression analysis showed that HOMA-IR was independently associated with BMIPP summed score in nondiabetic (beta=0.774, t=9.218, P=0.0001) and diabetic patients (beta=0.792, t=9.079, P=0.0001). Left ventricular ejection fraction was lower in nondiabetic subjects with BMIPP summed score of at least 6 plus HOMA-IR of at least 4 than in others with lower values for both assessments (53.1+/-13.8%, n=20 vs 67.7+/-9.1%, n=23, P=0.0002); this was also true in diabetic subjects (50.9+/-15.2%, n=24 vs 71.0+/-13.6%, n=11, P=0.0007). Association between insulin resistance and impaired cardiac fatty acid metabolism may contribute to left ventricular dysfunction in patients with maintenance hemodialysis without coronary diseases.

Aged↗

PubMed2003

Delimitation of the fertility restorer locus Rfk1 to a 43-kb contig in Kosena radish (Raphanus sativus L.).

We are pursuing a positional cloning strategy to isolate the fertility restoration gene Rfk1 from radish. Random polymorphic DNA-sequence-tagged site (RAPD-STS) markers tightly linked to the gene in radish were isolated, and a RAPD map surrounding the Rfk1 locus was constructed. We surveyed 948 F2 plants with adjacent RAPD-STS markers to isolate recombinants for bulk segregant analysis. This analysis was effective in isolating tightly linked amplification fragment length polymorphism (AFLP) markers surrounding the gene of interest. Ten tightly linked AFLP markers were obtained and used to construct a high-resolution map of the region. The closest AFLP-STS markers flanking Rfk1 were 0.1 cM and 0.2 cM away. Using the four adjacent AFLP markers, we screened lambda and cosmid libraries. The lambda and cosmid clones were aligned by examination of end sequences and restriction fragment length polymorphism (RFLP) patterns for each clone, and by hybridization to the DNA isolated from recombinants. Finally, we constructed a 198-kb contig encompassing the Rfk1 gene and comprising 20 lambda and two cosmid clones. By analysis of the breakpoints in recombinants with the rfk1/rfk1 or Rfk1/- genotype, the Rfk1 locus could be assigned to a 43-kb region comprising four lambda clones and one cosmid clone. This pinpoint localization in the radish genome has made it possible for us to identify the gene by sequence analysis and genetic transformation of cytoplasmic male-sterile Brassica napus plants.

Blotting, Southern↗

PubMed2002

Therapeutic effects of milnacipran, a serotonin and noradrenaline reuptake inhibitor, on post-stroke depression.

Depression is common after stroke. While several reports have been published on the use of antidepressants such as selective serotonin reuptake inhibitors and tricyclics for the treatment of post-stroke depression (PSD), no previous study has examined the use of a selective serotonin and noradrenaline reuptake inhibitor (SNRI) for this condition. The present study investigated the efficacy and safety of milnacipran, a SNRI, for the treatment of PSD. A 6-week open study was conducted in 12 patients (two males and 10 females) aged 53-88 years. All patients were diagnosed with major or minor depressive disorder according to DSM-IV, where onset was subsequent to a cerebral infarction or haemorrhage (stroke). Severity of depression was assessed using the 21-item Hamilton rating scale for depression (HAM-D). The maximum total daily dose of milnacipran was in the range of 30-75 mg b.i.d. Three patients experienced side-effects, but none of the side-effects were serious. Two patients dropped out of the study. At the end of the study, 58.3% (7/12) of the total patient population and 70% (7/10) of the patients completing the study were in remission (a final HAM-D score of less than 7 and no longer meeting criteria for major or minor depression). These results suggest that milnacipran may be an effective treatment for PSD.

Administration, Oral↗

PubMed2001

Analysis of recurrence of squamous cell carcinoma of the uterine cervix after definitive radiation therapy alone: patterns of recurrence, latent periods, and prognosis.

PURPOSE: A retrospective analysis was performed with emphasis on the patterns of recurrence, latent period, and prognosis in patients with cervical squamous cell carcinoma of the uterus treated with definitive radiation therapy alone. Late recurrence, which was observed more than 5 years after the initial radiation therapy, was finally focused on and discussed. MATERIALS AND METHODS: Between 1976 and 1994, 256 patients with squamous cell carcinoma of the uterine cervix without hematogenous metastasis were treated with definitive radiation therapy alone. The patients were staged as follows according to the FIGO classification: 26 in Stage I, 56 in Stage II, 124 in Stage III, 28 in Stage IVa, and 22 in Stage IVb. All the patients were treated with external beam irradiation and low-dose-rate intracavitary brachytherapy. RESULTS: A total of 74 patients had recurrence. The recurrence appeared in 67 cases (90.5%) within 5 years. Metastasis to para-aortic and/or supraclavicular nodes developed later than other types of recurrence. Among patients with lymphogenous metastasis, there were more 5-year survivors after recurrence than with other types of recurrence. Patients with early recurrence, within 2 years of the initial therapy, had a worse prognosis than those with recurrence more than 2 years after treatment. Seven patients (2.7%) in all developed late recurrence more than 5 years after the treatment. The first site of recurrence was an abdominal para-aortic or supraclavicular node in all patients, excluding one patient who developed intrapelvic lymph node metastasis. Six patients had pelvic node metastasis detected with lymphangiography at the initial treatment. Median survival after late recurrence was 16.0 months. Two of 7 patients survived more than 3 years after secondary radiation therapy, and the remainder died of recurrent disease. CONCLUSION: Patients with para-aortic and/or supraclavicular node metastasis that developed late after the initial treatment are more likely to survive due to secondary radiation therapy. Careful follow-up is emphasized for long-term survivors.

Aged↗

PubMed2001

Multiple mechanisms regulate expression of low temperature responsive (LOT) genes in Saccharomyces cerevisiae.

Using cDNA subtraction screening, we identified five Saccharomyces cerevisiae genes whose expressions is up-regulated when culture temperature was down-shifted from 30 to 10 degrees C. Among these LOT (low temperature-responsive) genes, three (LOT1, LOT2, and LOT3) were identical to FBA1, RPL2B, and NOP1, encoding a fructose biphosphate aldolase, a ribosomal protein L2B, and a nucleolar protein for rRNA processing, respectively. No functions were assigned for LOT5 and LOT6, which are identical to YKL183w and YLR011w, respectively. Northern hybridization analysis revealed that these genes are not uniformly regulated in response to the change of growth temperature. In addition, all the LOT genes, except for LOT1/FBA1, were induced by a low concentration of cycloheximide. The data indicate that multiple mechanisms, including translational functionality may be involved in the regulation of LOT gene expression in yeast.

Base Sequence↗

PubMed2001

Small cell lung cancer with a brain metastasis controlled for 5 years: a case report.

We report a case of small cell lung cancer whose initial presentation was a solitary brain metastasis. On chest radiography the primary tumor was unclear and only detected by bronchofiberscopy. A small single pulmonary metastasis was noted in the right lower lobe. Subtotal resection and external irradiation were applied to the brain tumor and external irradiation was applied to the lung. Concurrently one course of systemic chemotherapy was administered. The tumors in the brain and lung had disappeared by the end of the treatment. The patient has been alive and well for 5 years without recurrence.

Brain Neoplasms↗

PubMed2001

Acute canine model for drug-induced Torsades de Pointes in drug safety evaluation-influences of anesthesia and validation with quinidine and astemizole.

An acute in vivo model for drug-induced torsades de pointes (TdP) for use in safety evaluation of drugs was developed using dogs with acute complete atrioventricular (AV) block. In order to study the effects of anesthetic agents on the inducibility of TdP, arrhythmias were induced by programmed electrical stimulation (PES) before and after cumulative intravenous administration of quinidine under anesthesia with sodium pentobarbital, halothane, or isoflurane. Both prolongation of the QTc and the incidence of TdP were greatest in dogs anesthetized with halothane and were smallest in those given pentobarbital, suggesting that halothane is the most suitable anesthetic for this TdP model. To further validate this model, astemizole was administered intravenously to other dogs under halothane anesthesia. Astemizole at 0.3 mg/kg caused slight prolongation of the QT interval but did not induce any arrhythmias. At 1 mg/kg, however, TdP were induced in 5 of 10 animals and in an additional 2 animals at 3 mg/kg. Single and multiple ectopic beats preceded the induction of TdP, and the ectopic beats were observed in a dose-dependent manner. The plasma concentrations of quinidine in dogs with TdP were equivalent to or less than quinidine levels in humans with TdP, while those of astemizole were higher in dogs. In conclusion, this acute canine model of TdP with halothane anesthesia, complete AV block, PES, and simultaneous measurements of plasma drug concentration would be valuable for assessing the risk of drugs, especially I(Kr) blockers, to induce TdP in humans.

Acute Disease↗

PubMed2001

Amino acid sequence and characterization of a rice bran ribonuclease.

A base-nonspecific and acid ribonuclease (RNase Os) belonging to the RNase T2 family was purified from rice bran to a homogeneous state by SDS-PAGE. The primary structure of RNase Os was determined by protein chemistry and molecular cloning. The RNase Os was a simple protein and consisted of 205 amino acid residues. Its molecular weight was 22578 and its amino acid sequence showed that it was most similar to barley RNase among the known RNase T2 family enzymes having 157 amino acid residues identical with barley RNase. However, its N-terminus was blocked by a gamma-pyroglutamyl residue. The optimal pH of RNase Os was around 5.5. The base preference at the B1 and B2 site of RNase Os was estimated from the rates of hydrolysis of 16 dinucleoside phosphates, to be guanine as the case of RNase LE from tomato. RNase Os was successfully expressed from yeast cells using the E. coli yeast expression vector pYE-RNAP.

Amino Acid Sequence↗

PubMed2000

Bombelli's valgus-extension osteotomy for osteoarthritis due to acetabular dysplasia: results at 10 to 14 years.

Severe osteoarthritis due to acetabular dysplasia (n = 17) was treated with valgus-extension osteotomy, and the patients' clinical outcomes 10-14 years after operation were evaluated according to clinical factors (Japanese Orthopaedic Association hip score; JOA score) and by roentgenography. The mean JOA score 10 years or later had improved by 22 points compared with the preoperative score. On roentgenography, joints which had preoperative roof osteophyte had better postoperative formation of roof osteophyte. The JOA score was higher in the 12 joints which had osteophyte 5 mm or longer than in those joints with osteophyte that was 5 mm or shorter. Postoperative joint space widening occurred in 15 joints (88.2%) 3-6 months postoperatively, and it reached the maximum at 3-5 years. In patients who had a large bone cyst in the femoral head preoperatively, the cyst collapsed, and deformation of femoral head occurred after operation, but remodeling of the joint surface occurred naturally and the congruity improved. In the 6 joints in which the preoperative acetabular head index was less than 60% and the acetabular angle was larger than 30 degrees, the JOA score at 10 years or later was lower than that of the other joints. Based on these findings, valgus-extension osteotomy was evaluated as a useful surgical method for advanced or terminal osteoarthritis in young or middle-aged patients. Predictive factors for long-term prognosis would be the preoperative length of roof osteophyte, joint space widening, and the degree of femoral head covering.

Adolescent↗

PubMed2000

Expression of plant group 2 and group 3 lea genes in Saccharomyces cerevisiae revealed functional divergence among LEA proteins.

To study functions of late embryogenesis abundant (LEA) proteins, which accumulate in plant cells under water deficit conditions, in vivo functional analyses were carried out using a yeast (Saccharomyces cerevisiae) heterologous expression system. Two lea genes, tomato le4 (group 2) and barley HVA1 (group 3), were expressed under the GAL1 promoter, and the gene products were detected using specific antisera. The growth of the transformants was scored and compared with a control strain to analyze the effect of these proteins on yeast cells under stress conditions. The yeast cells expressing HVA1 showed shorter lag period when transferred to a medium containing 1.2 M NaCl as compared to a control strain, while the cells expressing le4 did not show improved growth. Attenuated growth inhibition in a medium containing 1.2 M KCl was observed in the yeast cells expressing le4 and HVA1. No obvious growth improvement was observed in a high sorbitol medium in the cells expressing either le4 or HVA1. Increased freezing tolerance was observed in both lea-expressing cells, while no effect on heat tolerance was observed. These results support the hypothesis that different LEA proteins play a distinctive role in the protection against cellular dehydration.

Freezing↗

PubMed2000

Plasma soluble interleukin-2 receptor levels during and after upper abdominal surgery.

Soluble interleukin-2 (IL-2) receptor (sIL-2R) is reported to be up-regulated in inflammatory disorders. Although sIL-2R may modulate perioperative inflammatory responses, it remains unclear whether upper abdominal surgery affects plasma sIL-2R levels. We evaluated the influence of major abdominal surgery on plasma sIL-2R levels. Ten patients scheduled for upper abdominal surgery received anaesthesia with isoflurane, nitrous oxide, and epidural block. Plasma sIL-2R and IL-6 levels were determined at pre-anaesthesia, 0, 2, and 4 hours during surgery, and on postoperative days 1 (POD1) and 3 (POD3). The plasma levels of sIL-2R decreased significantly and achieved their minimum value at 4 hours (677.0 +/- 125.3 pg/ml, P < 0.01 compared to pre-anaesthesia value; 924.5 +/- 178.8 pg/ml, 95% confidence interval = 122.2-550.4). The plasma sIL-2R levels increased on POD1 (1336.5 +/- 174.0 pg/ml) and POD3 (1629.0 +/- 262.8 pg/ml), and reached a level significantly higher than the baseline (P < 0.05 and P < 0.001, 95% confidence interval = 93.4-730.6 and 402.8-1006.2, respectively). The plasma sIL-2R levels on POD3 significantly correlated with the peak IL-6 levels (r = 0.67, P < 0.05). The plasma sIL-2R levels on POD3 correlated with the amount of intraoperative bleeding (r = 0.66, P < 0.05). In conclusion, we found that major abdominal surgery induces characteristic changes in plasma soluble IL-2 receptor levels.

Abdomen↗

PubMed1999

Regulation of gibberellin biosynthesis genes during flower and early fruit development of tomato.

Gibberellins (GAs) are essential for the development of fertile flowers in tomato, and may also be required immediately after fertilization. In the GA-biosynthetic pathway, the reactions catalyzed by GA 20-oxidases have been implicated as site of regulation. To study the regulation of GA biosynthesis in flower and early fruit development, we isolated three tomato GA 20-oxidase cDNA clones, Le20ox-1, -2 and -3. The three genes showed different organ-specific patterns of mRNA accumulation. Analysis of the transcript levels of the three GA 20-oxidase genes, as well as those of copalyl diphosphate synthase (LeCPS) and GA 3 beta-hydroxylase (Le3OH-2) during flower bud and early fruit development, revealed temporally distinct patterns of mRNA accumulation. Up until anthesis, transcripts were observed for LeCPS, Le20ox-1, -2 and Le3OH-2, with an accumulation of Le20ox-1 mRNA. In contrast to the high level of Le3OH-2 transcripts in the fully open flower, mRNA levels of Le20ox-1, -2 and LeCPS were reduced at this stage. After anthesis, LeCPS and Le20ox-1 transcripts increased again. In addition, Le20ox-3transcripts increased whereas the transcripts of Le3OH-2 decreased to an undetectable level. In situ hybridization results demonstrated that during early stages of bud development, Le20ox-2 transcripts were localized in the tapetum and placenta. The presented results supply novel data about localization of GA biosynthesis gene transcripts, and indicate that transcript levels of GA biosynthesis genes are all highly regulated during flower bud development.

Alkyl and Aryl Transferases↗

PubMed1999

The coupling of differential display and AFLP approaches for nonradioactive mRNA fingerprinting.

We have modified the differential display of 3'-end restriction fragments of cDNA technique by combining it with the amplified fragment length polymorphism (AFLP) approach and silver staining. Modified oligo-dT primers were used for a reverse transcription step. ds cDNA was digested with the Mse I restriction enzyme and then ligated with an AFLP adapter. The modified template was amplified with oligo-dT primers in a preamplification step (asymmetric PCR) that enriched the template for 3'-end sequences; subsequently, the enriched template was amplified with an AFLP primer having a selective extension and an anchored oligo-dT primer (conventional PCR step). We demonstrated that the asymmetric preamplification step facilitates the preferential amplification of 3'-end fragments and the resulting PCR products can be clear resolved on silver-stained gel. The presented procedure takes advantages of silver-stained gels, generates reproducible display patterns, and allows reliable reamplification of isolated fragments which contain both upstream and downstream primer sequences.

Blotting, Northern↗

PubMed1998

[Intraoperative transient incomplete left bundle branch block in a patient with left axis deviation in pre-anesthetic electrocardiogram].

We encountered a case of transient incomplete left bundle branch block (TILBBB) during standard mastectomy under general anesthesia. The patient was a 40 year-old female (70 kg, 164 cm) without any abnormalities on preanesthetic examinations except -61 degrees left axis deviation in exercise electrocardiogram. Adriamycin 20 mg was administered preoperatively. After the skin incision, heart rate increased from 104 min-1 to 130 min-1 and the cardiac axis gradually rotated leftward with increasing Q wave depth on leads I and aVL. We diagnosed this as blockade of the anterior branch in the left bundle branch. After the administration of fentanyl (0.2 mg) and sevoflurane (3%), the heart rate decreased to 105 min-1 and the electrocardiogram returned to the initial wave form. This anesthetic course indicated that adriamycin had slightly damaged the cardiac muscle and inadequate anesthesia had caused tachycardia and transient left bundle branch block. Left axis deviation on preoperative exercise electrocardiogram suggests that the left bundle branch can easily be blocked with an increasing heart rate. Adequate depth of anesthesia would have prevented the increase in heart rate and abnormality in the cardiac conduction process.

Adult↗

PubMed1997

Ent-kaurene synthase from the fungus Phaeosphaeria sp. L487. cDNA isolation, characterization, and bacterial expression of a bifunctional diterpene cyclase in fungal gibberellin biosynthesis.

ent-Kaurene is the first cyclic diterpene intermediate of gibberellin biosynthesis in both plants and fungi. In plants, ent-kaurene is synthesized from geranylgeranyl diphosphate via copalyl diphosphate in a two-step cyclization catalyzed by copalyl diphosphate synthase and ent-kaurene synthase. A cell-free system of the fungus Phaeosphaeria sp. L487 converted labeled geranylgeranyl diphosphate to ent-kaurene. A cDNA fragment, which possibly encodes copalyl diphosphate synthase, was isolated by reverse transcription-polymerase chain reaction using degenerate primers based on the consensus motifs of plant enzymes. Translation of a full-length cDNA sequence isolated from the fungal cDNA library revealed an open reading frame for a 106-kDa polypeptide. The deduced amino acid sequence shared 24 and 21% identity with maize copalyl diphosphate synthase and pumpkin ent-kaurene synthase, respectively. A fusion protein produced by expression of the cDNA in Escherichia coli catalyzed the two-step cyclization of geranylgeranyl diphosphate to ent-kaurene. Amo-1618 completely inhibited the copalyl diphosphate synthase activity of the enzyme at 10(-6) M, whereas it did not inhibit the ent-kaurene synthase activity even at 10(-4) M. These results indicate that the fungus has a bifunctional diterpene cyclase that can convert geranylgeranyl diphosphate into ent-kaurene. They may be separate catalytic sites for the two cyclization reactions.

Alkyl and Aryl Transferases↗

PubMed1997

[A procedure for electroretinogram (ERG) recording in mice--effect of monoiodoacetic acid on the ERG in pigmented mice].

A procedure for recording the electroretinogram (ERG) in pigmented mice, C57BL, based on the ERG recording technique reported previously in albino mice, ICR, and giving careful consideration to the influence of anesthetics and dark-adaptation, was developed in order to examine retinal toxicity. Pigmented mice were given a single i.v. injection of monoiodoacetic acid (IAA), a known retinotoxic compound, via a tail vein at a dose of 30, 45 or 60 mg/kg, and the ERG was recorded periodically over the next 14 days. In addition, the retinas were examined histopathologically on day 15. The results were as follows. 1. The oscillatory potentials were not distinct in the ERGs from mice anesthetized with pentobarbital as compared to the ERGs from non-anesthetized mice. ERG waveforms obtained from mice anesthetized with a mixture of urethane, xylazine and ketamine or xylazine and ketamine were almost the same as those obtained from non-anesthetized mice. Therefore, the ERGs were recorded under mixed anesthesia, ketamine and xylazine, in the following study. Stable ERGs could be recorded after 40 min of dark-adaptation. 2. IAA at doses of 30 and 45 mg/kg caused slight depression of the amplitudes of the a-, b- and c-waves; however, these changes were no longer observed 7 days after dosing. At a dose of 60 mg/kg, the ERG waves were markedly depressed 1 day after dosing, and recovery was not observed until day 14. 3. Upon histopathologic examination of the retinas, a remarkable decrease in visual cells and thinning of the rod and cone layers and outer plexiform layer were observed with IAA at a dose of 60 mg/kg. 4. Using this newly developed recording technique, it was confirmed that stable ERGs could be recorded from pigmented mice repeatedly for 14 days, and the effects of IAA on the ERG could be detected. Histopathological abnormalities in the retinas correlated well with the changes in the ERGs. These results indicate that the newly developed ERG recording procedure is useful for evaluating retinal toxicity in pigmented mice.

Anesthesia↗

PubMed1997

[Liver metastases from breast cancer 14 years after radical mastectomy; successful treatment with hepatic arterial infusion chemotherapy and systemic endocrine therapy--a case report].

The patient was a 73-year-old woman who was admitted to our hospital for epigastric discomfort and body weight loss. She had undergone radical right mastectomy in March 1982. Ultrasonography and computed tomography revealed multiple tumors in the liver. Three of the tumor markers (CA-125, CA 19-9, and CA 15-3) were positive. US-guided fine needle aspiration biopsy of the liver tumor showed small atypical cells with solid cell nests. Immunohistochemical tests revealed estrogen receptor was positive. We diagnosed the patient as recurrent breast cancer metastatic to liver, 14 years postoperatively. The liver tumors were successfully controlled with the combination of intra-arterial infusion chemotherapy (5-fluorouracil, epirubicin, and mitomycin C) along with systemic endocrine therapy (medroxyprogesterone acetate and fadrozole hydrochloride hydrate).

Aged↗

PubMed1996

A lea-class gene of tomato confers salt and freezing tolerance when expressed in Saccharomyces cerevisiae.

During periods of water deficit, plants accumulate late embryogenesis-abundant (LEA) proteins which are thought to protect cells from stresses associated with dehydration. One of these genes, le25, is expressed in tomato leaves and roots in response to water deficit and abscisic acid accumulation. To study the function of this protein and to test the effect of overproduction of the LE25 protein in Saccharomyces cerevisiae (Sc), a recombinant plasmid in which le25 is expressed under the control of the GAL1 promoter was constructed. The content of LE25 was high in Sc cells transformed with the recombinant plasmid. The transformant exhibited several stress-tolerant phenotypes. Growth of the transformant in a medium with 1.2 M NaCl was improved, as compared to a control strain. While the control strain showed a long lag phase of 40 h, le25-expressing cells showed a shortened lag phase of 10 h. However, no growth improvement was observed in a medium with 2 M sorbitol. In addition, the transformant had an increased survival rate after freezing stress, but not after high-temperature stress. These results, together with its predicted secondary structure, may indicate that LE25 functions as an ion scavenger.

Culture Media↗