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Biomedical subjects

S Imai

Publications and source records attributed to S Imai.

At least 289 records · Page 16Linked to original sources
PubMed1994

Ventricular unloading and improvement in left ventricular function after angiotensin converting enzyme inhibition with enalapril in patients with chronic congestive heart failure.

To clarify how angiotensin converting enzyme inhibition affects left ventricular function through ventricular unloading, ventricular wall stress, ventricular volumes, and other cardiac indices and exercise tolerance were evaluated in 17 patients with mild to moderate chronic congestive heart failure before and after 3 months of treatment with enalapril. Echocardiographic examination revealed that treatment with this angiotensin converting enzyme inhibitor resulted in significant reductions in end-systolic wall stress (117 +/- 25 to 89 +/- 28 g/cm2, p < 0.01) and left ventricular volume indices (end-diastolic: 163 +/- 56 to 143 +/- 60; end-systolic 99 +/- 51 to 77 +/- 57 ml/m2 p < 0.01). Ejection fraction (42 +/- 11 to 48 +/- 13%, p < 0.01) and systolic blood pressure/end-systolic volume (SBP/ESV; 1.06 +/- 0.30 to 1.33 +/- 0.48 mmHg/ml, p < 0.01) were both increased. By radionuclide ventriculography, ejection fraction and peak ejection rate (2.30 +/- 0.74 to 2.80 +/- 0.76 EDV/sec, p < 0.01) were increased, while time to peak ejection, time to peak filling, and peak filling rate were unchanged. Heart rate and double product at exercise were decreased and delta EF was significantly increased (-1.4 +/- 4.1 to 1.6 +/- 4.4%, p < 0.02). The decrease in end-systolic wall stress was consistently related to both the increase in ejection fraction and SBP/ESV, while the decrease in end-diastolic volume was related only to SBP/ESV and not to ejection fraction. Furthermore, there was a direct relationship between the decrease in systolic wall stress and the decrease in end-diastolic volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Genetic control of the radiosensitivity of lymphoid cells for antibody formation ability in mice.

To analyze the genetic basis of the relationship between the radiosensitivity of the immune response and radiation lymphomagenesis, we examined the radiosensitivity of lymphoid cells for antibody formation in BALB/cHeA, STS/A, F1 hybrids, and their recombinant inbred mouse strains. The decrease in the number of plaque-forming spleen cells in BALB/cHeA mice exposed to 3 Gy X-irradiation was more than tenfold that in STS/A mice. The phenotype of radioresistance was dominant over sensitivity. The coincidence between the strain distribution patterns of the genetic markers and radiosensitivities of antibody formation in the various recombinant inbred strains was in the region with the Igh locus on chromosome 12. There was obvious difference between the patterns in the region containing the Ifa locus on chromosome 4 which has been shown to be related to the incidence of radiation-induced lymphomas. These results indicate that the region on chromosome 12 may contain major gene(s) related to radiosensitivity for antibody formation.

Animals↗
PubMed1994

Rumen ciliate composition and diversity of Japanese beef black cattle in comparison with those of Holstein-Friesian cattle.

The composition of ciliate protozoa in the rumen of 30 Japanese beef black cattle (Bos taurus taurus) fed in Yoron Island, Kagoshima, was compared with that of 125 Holstein-Friesian cattle (Bos taurus taurus) fed in Hokkaido. Thirteen genera including 44 species with 32 formae detected from Japanese beef black cattle and 15 genera including 48 species with 25 formae from Holstein-Friesian cattle were identified. Thirty-six species with 19 formae were common to both hosts. A new species was recognized from Japanese beef black cattle and named Entodinium yunnense n. sp. This new species was classified into such four formae as yunnense n.f., spinonucleatum n.f., acutonucleatum n.f. and spinolobum n.f. A new forma of Entodinium bifidum having only one caudal spine was also recognized from Japanese beef black cattle and named monospinosum n.f. The average ciliate density in Japanese beef black cattle, 18.7 x 10(4)/ml, was lower than 40.3 x 10(4)/ml in Holstein-Friesian cattle. The average number of ciliate species per head in Japanese beef black cattle, 14.4 was also lower than 17.8 in Holstein-Friesian cattle. The average value of diversity index was 1.789 in Japanese beef black cattle and 1.718 in Holstein-Friesian cattle. Both incidence and composition ratio of Entodinium rectangulatum and E. ovinum were significantly higher in Japanese beef black cattle than in Holstein-Friesian cattle. On the other hand, Charonina ventriculi, E. caudatum, E. rostratum, E. parvum, E. bursa, Metadinium affine and Ostracodinium mammosum showed a reverse relation.

Animals↗
PubMed1994

Pleural multicystic mesothelial proliferation.

We report a rare case of pleural multicystic mesothelial proliferation occurring in a 62-year-old Japanese woman. Macroscopically, the lesion consisted of multiple thin wall cysts containing clear serous fluid. Histologic studies, including hematoxin-eosin stain, as well as the immunohistochemical method, revealed that the lesion was mesothelial in origin and consistent with a reactive change.

Antigens↗
PubMed1994

Holter monitoring as a noninvasive indicator of cardiac involvement in sarcoidosis.

We investigated the usefulness of 24-h Holter monitoring for identification of myocardial involvement in 38 patients with sarcoidosis, including 12 patients with cardiac sarcoidosis, and 58 healthy controls. Ventricular ectopic beats (VEB) > or = 100 beats per day were detected in 8 (67 percent) of 12 patients with cardiac sarcoidosis, in 2 (8 percent) of 26 patients without cardiac sarcoidosis, and in 3 (5 percent) of 58 healthy controls. Holter monitoring was associated with a sensitivity of 67 percent and a specificity of 62 percent for cardiac sarcoidosis in the overall study population. In patients with sarcoidosis, specificity was 80 percent. Lown's grade 4 A and 4 B VEBs were detected in 8 (67 percent) of 12 patients with cardiac sarcoidosis, in 2 (8 percent) of 26 patients with sarcoidosis without cardiac involvement, and in 2 (3 percent) of 58 controls. Holter monitoring was associated with a sensitivity of 67 percent and a specificity of 80 percent for identification of cardiac involvement in patients with systemic sarcoidosis. Our findings suggest that 24-h Holter monitoring provides a convenient and inexpensive means of noninvasive screening for cardiac involvement in generalized sarcoidosis, even in patients and outpatients who are without symptoms.

Cardiac Complexes, Premature↗
PubMed1994

[A case of multiple nodular pulmonary amyloidosis associated with Sjögren's syndrome].

A 58-year-old female, who had complained of dryness of the conjunctiva and mouth for nine years, was admitted to our hospital because chest X-ray films revealed increases in both the size and the number of pulmonary nodules in comparison to four years earlier. Histological findings of the salivary gland biopsy confirmed a diagnosis of Sjögren's syndrome. An open lung biopsy was performed. Histologically, the pulmonary nodules consisted of homogeneous, acellular eosinophilic materials, which were identified as amyloid by Congo red staining. Immunohistochemical examination showed the amyloid to be composed of AA protein. There were no deposits in other organs. Peribronchial lymphocytic infiltration associated with Sjögren's syndrome was present. Nodular pulmonary amyloidosis with Sjögren's syndrome is very rare condition. To our knowledge, this case is only the ninth to be reported in the literature.

Female↗
PubMed1994

Comparative effects of milk, yogurt, butter, and margarine on mammary tumorigenesis induced by 7,12-dimethylbenz(a)anthracene in rats.

The effects of margarine and butter on mammary tumorigenesis were compared in the first experiment. Altering the levels of dietary margarine and butter influenced the development of mammary tumors induced with 7,12-dimethylbenz(a)anthracene (DMBA) in rats. Margarine enhanced tumorigenesis dose dependently in both the incidence and the number of mammary tumors. On the other hand, butter that was substituted for margarine did not show any enhancing effects. Inasmuch as butter is made from cow's milk, the effect of cow's milk was studied in the second experiment. It was expected that milk might inhibit mammary tumorigenesis. Contrary to our expectations, however, milk and yogurt did not inhibit but enhanced the DMBA-induced mammary tumorigenesis. It remains to be elucidated whether the enhancing effect was caused by some specific factors in milk or by the difference in energy or nutrient intakes.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1994

Cervical radiculomyelopathy due to deposition of calcium pyrophosphate dihydrate crystals in the ligamentum flavum: historical and histological evaluation of attendant inflammation.

Deposition of calcium pyrophosphate dihydrate (CPPD) crystals in the yellow ligament occasionally leads to neurological deficits through compression of the spinal cord. Although it is widely accepted that CPPD crystal induces severe inflammation in arthropathy, little attention has been paid to the acute inflammation that may accompany the CPPD crystals in the ligamentum flavum. The present study reviews eight patients with radiculomyelopathy due to calcification of the cervical yellow ligament. Acute inflammation of the yellow ligament accompanying the crystalline deposits, both with and without attendant granulation tissue-proliferation, was evaluated as contributing to cervical radiculomyelopathy. Three cases with attendant granulation tissue suffered from recurrent attacks of neck pain and fever with coincidental radicular pain in the upper arm. The local inflammation of the ligamentum flavum might have participated in the exacerbation of the cervical radiculopathy.

Aged↗
PubMed1994

[Bacteriological, pharmacokinetic and clinical studies on biapenem (L-627) in the pediatric field].

Antibacterial activities were determined and pharmacokinetics and a clinical studies were performed on biapenem (L-627), a novel parenteral carbapenem antibiotic, in infections in children. The following results were obtained: 1. MICs of L-627 against clinical isolates were as follows: Among Gram-positive bacteria, MICs were 0.78 microgram/ml to > 100 micrograms/ml against 3 strains of methicillin-resistant Staphylococcus aureus (MRSA), and 0.10 microgram/ml to 0.39 microgram/ml against 8 strains of methicillin-sensitive S. aureus (MSSA), MICs against 5 of them were similar to those of imipenem (IPM), and MICs against 3 of them were slightly higher than those of IPM. MICs were < or = 0.025 microgram/ml to 0.39 microgram/ml against 7 strains of Streptococcus pneumoniae, and were similar to those of IPM, and lower than those of ceftazidime (CAZ) and piperacillin (PIPC). Among Gram-negative bacteria, MICs were 0.78 microgram/ml and 3.13 micrograms/ml against 2 strains of Haemophilus influenzae, and were similar to those of IPM. 2. Maximum plasma concentrations determined by the bioassay method after intravenous infusion of L-627 over 30 minutes at doses of 6.0 and 12.0 mg/kg, respectively, in 2 different pairs of 2 children each (total 4 cases) were observed upon completion of the treatment. Maximum concentrations at a dose of 6.0 mg/kg were 28.8 micrograms/ml and 24.6 micrograms/ml, and at a dose of 12.0 mg/kg were 65.4 micrograms/ml and 39.6 micrograms/ml, exhibiting a dose response. Plasma half lives in the beta phase were 0.97 and 1.20 hours at 6.0 mg/kg, and 0.72 and 0.94 hour at 12.0 mg/kg. Plasma concentrations determined by the HPLC method were lower than those determined by the bioassay. 3. Urinary excretion rates in the first 5.5 hours after the 6.0 mg/kg dose were 81.4 and 75.3%, and after the 12.0 mg/kg dose were 91.0 and 73.8%, and these values were higher than those obtained using HPLC. 4. Concentrations of L-627 in cerebrospinal fluid were determined in 2 cases of purulent meningitis. In one case, 30.3 mg/kg of L-627 was infused intravenously over 30 minutes and concentrations on days 1, 3, 7 and 14 observed at 60, 60, 45 and 45 minutes after respective dosages were 7.60, 1.30, 1.42 and 0.38 microgram/ml. Cerebrospinal fluid-plasma concentration ratio was determined on days 7 and 14 to be 5.5 and 1.2% respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Bacterial Infections↗
PubMed1994

[Mechanical characteristics of the bovine choroid].

We studied the mechanical relationship between the tension and the length of stretch of bovine choroids. Longitudinal and circular choroidal strips (4 mm x 6 mm) were prepared at 3 different locations (I. ora serrata, II. anterior to the equator, III. posterior to the equator). Using a force transducer and a potentiometer, changes in the tension and the length of stretch were recorded simultaneously. At a tension of 600 mg, longitudinal strips stretched more than circular strips at all 3 locations (p < 0.05). Longitudinal strips all stretched to almost the same length (about 1.3 mm), but circular strips stretched less in the order of I, II and III. These results suggest that there are mechanical characteristics in the bovine choroid allowing it to stretch more in the longitudinal direction than in the circular direction.

Animals↗
PubMed1994

Etretinate-induced heterotopic bone formation about the hip joint. A case report including ultrastructural study.

Despite considerable documentation for retinoid-induced hyperostosis, sufficient knowledge regarding its management and histologic features is not available. In a 26-year-old man with etretinate-induced heterotopic bone formation about the hip joint, the use of etidronate disodium was unsuccessful. Surgical excision of the heterotopic bone dramatically improved restricted motion of the hip joint without initiating significant postoperative heterotopic ossification. Ultrastructural study showed abundant myofibroblasts in the fibrous tissue close to the heterotopic bone. Their role in local biologic events should be determined.

Adult↗
PubMed1994

Intracranial blood flow measured with single photon emission computer tomography (SPECT) during transient -6 degrees head-down tilt.

Regional cerebral blood flow (CBF) during a transient head-down tilt of -6 degrees (-6 degrees HDT) was measured with single photon emission computer tomography (SPECT). CBF was measured and averaged for both sides of the brain areas; e.g., the bilateral anterior cerebral artery (bACA) area, the middle cerebral artery (bMCA) area, the posterior cerebral artery (bPCA) area, bilateral basal ganglia, and the cerebellum. Among these areas, a significant increase in CBF was observed in the basal ganglia and the cerebellum during -6 degrees HDT compared to pre-HDT. When CBF was measured separately in the left or right brain area, these significances disappeared, although a trend of increase or decrease was still observable. A trend of increase was observed in the left anterior cerebral artery (IACA) area, the right middle cerebral artery (rMCA) area, the right posterior cerebral artery (rPCA) area, the left and right basal ganglia, and the cerebellum. In rACA, IMCA and IPCA areas, a slight decrease in CBF was observed. At the same time, cardiac parameters were measured. Heart rate (HR), stroke volume (SV) and cardiac output (CO) did not change significantly, although SV slightly increased and HR slightly decreased during -6 degrees HDT.

Adult↗
PubMed1993

Regulation of activity levels of glycolipid sulfotransferases by transforming growth factor alpha in renal cell carcinoma cells.

Accumulation of sulfolipids associated with markedly elevated levels of glycolipid sulfotransferase activities was previously demonstrated in human renal cell carcinoma cells. To explore the regulation mechanisms of sulfoglycolipid synthesis in renal cancer, effects of various growth factors on the metabolic enzymes of sulfoglycolipids were investigated by using a human renal cell carcinoma cell line, SMKT-R3. Among the growth factors tested, transforming growth factor alpha (TGF-alpha) and epidermal growth factor (EGF) were found to increase the sulfotransferase activity markedly (about 300%), but did not change that of arylsulfatase A, which hydrolyzes sulfoglycolipids. The augmented effects of TGF-alpha was abolished by cycloheximide. Since TGF-alpha is known to bind to the same receptor as EGF, SMKT-R3 cells were investigated for the EGF receptor by affinity cross-linking with 125I-EGF. A radiolabeled protein with a molecular mass of 175 kDa corresponding to the ligand-receptor complex was immunoprecipitated with a monoclonal anti-EGF receptor antibody. When production of the growth factors was examined immunochemically, the cells were found to secrete TGF-alpha at a low level and retain it in a membrane-bound form, whereas EGF was not detected. These observations suggest that the sulfotransferase activities are regulated through the autocrine, paracrine, and/or juxtacrine modes of intercellular stimulation by TGF-alpha in human renal cancer cells.

Carcinoma, Renal Cell↗
PubMed1993

Lidocaine suppresses the sodium current in Euhadra neurons which is mediated by cAMP-dependent protein phosphorylation.

The action of a local anesthetic, lidocaine, in association with the cyclic AMP (cAMP)-mediated intracellular biochemical process, was examined in identified Euhadra neurons. Lidocaine dose-dependently inhibited the inward current which was elicited by dibutyryl cAMP (db-cAMP) and isobutylmethylxanthine (IBMX). This inhibitory effect was transiently reversed by the intracellular injection of a catalytic subunit of a cAMP-dependent protein kinase. The inward current elicited by db-cAMP and IBMX was abolished by Na(+)-free saline but not by Ca(2+)-free saline. The data suggest that lidocaine is not acting directly on the Na+ channel, but acts at a level proximal to the catalytic subunit of cAMP-dependent protein kinase.

1-Methyl-3-isobutylxanthine↗
PubMed1993

Sphingosine activates cellular diacylglycerol kinase in intact Jurkat cells, a human T-cell line.

Sphingosine is known to regulate a variety of cellular functions through protein kinase C-dependent or independent pathways. In an attempt to investigate differential functions of diacylglycerol kinase (DGK) isozymes, we tested the effect of sphingosine on DGK operating in intact Jurkat cells, a human T-cell line. We found that phosphatidic acid (PA) synthesized from endogenous diacylglycerol (DG) and exogenously added short-chain DGs like dioctanoylglycerol were markedly enhanced by approx. 20 microM sphingosine. Further studies such as the use of protein kinase C down-regulated cells, mass measurements of cellular DGs, analysis of molecular species of PA and the effect of exogenous DG on the conversion of endogenous DG to PA suggested that sphingosine directly activated cellular DGK having a broad specificity toward DG molecular species.

Calcimycin↗
PubMed1993

Isolation and characterization of the human diacylglycerol kinase gene.

The 80 kDa diacylglycerol kinase (DGK) is abundantly expressed in oligodendrocytes and lymphocytes but not to a detectable extent in other cells such as neurons and hepatocytes. As an initial attempt to delineate the mechanism of the transcriptional control of the DGK gene, we have cloned from a human genomic library a 22 kb genomic fragment. The genomic clone consists of the 5'-flanking region and 17 exons coding for approx. 53% of the total exons of human DGK, including those encoding EF-hand and zinc-finger regions. The translation initiation site is located in the second exon. S1 nuclease mapping and primer extension analysis of the human DGK mRNA identified a major transcription initiation site (position +1) at 264 bp upstream from the initiator ATG. In the 5'-flanking sequence we detected a single GC box at -35 but no canonical TATA and CAAT sequences. However, the sequence starting from the cap site (AGTTCCTGCCA) is very similar to the initiator element that specifies the transcription initiation site of some housekeeping genes. In addition, the 5'-upstream region contains several putative cis-elements. Jurkat and HepG2 cells were transfected with various 5'-deletion mutants of the upstream region fused to the structural gene of chloramphenicol acetyltransferase (CAT). The CAT assay revealed that among constructs containing up to 3.4 kb of the 5'-flanking region, a fragment of 263 bp from the transcription initiation site contains a basic promoter that is active in both types of cells. Moreover, the region between -263 and -850 contains a negative element that is active in HepG2 but not in Jurkat cells. This negative element may, at least in part, be responsible for the cell type-specific expression of the DGK gene.

Animals↗