Biomedical subjects

M Shimizu

Publications and source records attributed to M Shimizu.

At least 739 records · Page 41Linked to original sources

PubMed1995

Transfer of rheumatoid arthritis into severe combined immunodeficient mice. The pathogenetic implications of T cell populations oligoclonally expanding in the rheumatoid joints.

To investigate the pathogenicity of T cells infiltrating in the rheumatoid joints, mononuclear cells (MNC), predominantly T cells, isolated from either synovial fluid or synovial tissues of the patients with RA were transferred into severe combined immunodeficient (SCID) mice by intraarticular injections. According to our observations in this experimental system, patients with RA could be classified into at least two groups. In one group of patients, the infiltrating MNC induced synovial hyperplasia in the recipient SCID mice (the positive group). Whereas, in the other group no synovial hyperplasia was observed (the negative group). The induction of synovial hyperplasia observed in the positive group was prevented by an anti-human CD3 antibody (OKT3), indicating T cell mediation. Analysis of T cell receptor (TCR) V beta usage by reverse transcriptase polymerase chain reaction in the infiltrating MNC transferred into SCID mice revealed a marked skew towards the preferential use of certain V beta genes, which was not seen in the peripheral blood MNC, in only the positive group. The patterns of TCR/V beta skew were not uniform among the patients. The analysis of the PCR-amplified genes of such skewed TCR/ V beta by single strand conformational polymorphism showed distinct bands, indicating that the T cell populations expanding in rheumatoid joints of the positive group were oligoclonal. Furthermore, the enrichment of the T cell populations expressing such skewed TCR/V beta by in vitro stimulation of peripheral blood MNC of the patients with the relevant superantigen enabled the induction of synovial hyperplasia in the SCID mice. These results suggest that the pathogenic T cells could be activated locally in rheumatoid joints by certain antigens in some, but not in all patients with RA.

Animals↗

PubMed1995

Panax ginseng extract improves the performance of aged Fischer 344 rats in radial maze task but not in operant brightness discrimination task.

The effect of Panax ginseng extract on the learning performance of aged Fischer 344 rats using the 8-arm radial maze task and the operant discrimination task was examined. Aged rats showed significantly impaired learning performance in both tasks. Daily administration of ginseng extract (8 g/kg/d, p.o. for 12-33 d) ameliorated the impairment of learning performance in the radial maze task but not in the operant discrimination task. These results suggest that subchronic treatment with ginseng extract improves spatial cognitive impairment in aged rats.

Aging↗

PubMed1995

The binding specificity and affinity of E. coli integration host factor (IHF) are influenced by the flexibility of flanking regions of its recognition sites.

To understand the roles of the 5'-flanking region of the recognition sites in binding specificity and the affinity of integration host factor (IHF), a variety of DNA fragments with a 13-bp consensus sequence, 5'-WATCAAN4TTR-3'[Friedman, Cell, 55, 545 (1988)], but with different 5'-flanking sequences were investigated by gel retardation and methylation interference assays. It has been well-established that the putative A/T rich element distal from the 5'-end of the consensus made a significant contributions to the binding of IHF. However, many of the DNA fragments used here revealed specific binding to IHF without such an A/T element. Several bases neighboring to the 5'-end of the consensus sequence had significant effects on the binding specificity as well as its affinity, and these results indicate that the sequence-directed bendability of the flanking region plays an important role in the specific recognition by IHF.

Autoradiography↗

PubMed1995

Panax ginseng extract improves the scopolamine-induced disruption of 8-arm radial maze performance in rats.

The effects of Panax ginseng ethanol extract and its water (WSF)- and lipid-soluble (LSF) fractions on the scopolamine-induced disruption of radial maze performance in rats were examined. Ginseng root was refluxed with ethanol, and WSF and LSF were prepared from this ethanol extract. Scopolamine (0.075-0.3 mg/kg, i.p.) dose-dependently impaired the maze performance. However, the oral administration of Panax ginseng ethanol extract and WSF (2-8 g dried root/kg) 90 min before testing improved the maze performance disrupted by scopolamine (0.3 mg/kg) in a dose-dependent manner, but LSF failed to attenuate the disruption. These data suggest that ginseng extract possesses a beneficial effect regarding spatial cognitive impairment and that the water-soluble fraction of ginseng extract mainly contributes to the effect of the ethanol extract.

Animals↗

PubMed1995

[New fluorogenic dienophile: synthesis, reaction with vitamin D, vitamin A and microcystins, and application to fluorometric assays].

We designed and synthesized a new sensitive and highly reactive fluorogenic reagent (1a, DMEQ-TAD) targeting a conjugated diene. DMEQ-TAD reacted quantitatively with major vitamin D metabolites and synthetic analogs under a variety of conditions to yield the corresponding 6,19-cycloadducts as a mixture of the C(6) epimers. The stereochemistry of the adducts was determined by their CD spectra on the basis of the exciton chirality method. The fluorescent products can be quantified linearly down to 10 fmol by HPLC. The new fluorometric method was successfully used in the assays of 25-OHD3, 24,25-(OH)2D3 and 25,26-(OH)2D3 in the human plasma. The method was proved to be reliable and precise compared with the HPLC-UV assay method. Reactions of DMEQ-TAD with retinoic acid (21a) and its geometrical isomers (21b-d) having a conjugated pentaene system afforded 7,10-adducts (24a-d) as major products together with 5,8-adducts (26a-d) in about 9:1 ratio (70-95% yield) except for the 9Z-isomer (21e) which gave only a 5,8,11,14-bis-adduct (27). DMEQ-TAD reacted with microcystins LR, YR and RR, at the conjugated diene part to yield 4,7-cycloadducts as a pair of epimers in good yield.

Fluorescent Dyes↗

PubMed1995

Effects of angiotensin-converting enzyme inhibitor and aldosterone antagonist on myocardial collagen in cardiomyopathic hamsters.

To examine the effects of angiotensin-converting enzyme (ACE) inhibitor and aldosterone antagonist on myocardial collagen in the cardiomyopathic hamster, the collagen concentration was measured by determining the hydroxyproline concentration, and the ratio of type I to type III collagen (type I/III ratio) was measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Five-week-old Bio14.6 cardiomyopathic hamsters were treated with the ACE inhibitor captopril (20 mg/kg per day) or the aldosterone antagonist K-canrenoate (20 mg/kg per day) in drinking water for 20 weeks, and the collagen concentration and type I/III ratio at 25 weeks were compared with those in 25-week-old untreated Bio14.6 and normal F1b hamsters. The collagen concentration markedly increased and the type I/III ratio significantly decreased (ie, type III collagen dominant) in untreated Bio14.6 compared with F1b at 25 weeks. Captopril and K-canrenoate treatment significantly reduced the collagen concentration and reversed the changes in the type I/III ratio in cardiomyopathic hamster. These results suggest that ACE inhibitor and aldosterone antagonist improve myocardial collagen in the cardiomyopathic hamster, not only quantitatively but also qualitatively, and that the mechanism of this improvement may be related to the cardiac renin-angiotensin-aldosterone system.

Aging↗

PubMed1995

A case of right atrial myxoma--effect of large myxoma in the right atrium studied by M-mode and Doppler echocardiography.

Doppler profiles are rarely used to assess cardiac function that has been partially impaired by a sizeable myxoma in the right atrium or to evaluate the improvement caused by extirpation of the tumor. In a 54-year-old man with a large right atrial myxoma (6.5 x 5.5 x 4.0 cm) along with first-degree atrioventricular (AV) block, M-mode and pulsed Doppler echocardiography were used to evaluate the left ventricular systolic and diastolic function before and 1 month after surgical removal of the myxoma. End-diastolic left ventricular (LV) and left atrial diameters increased postsurgically from 47 to 51 mm and from 38 to 41 mm, respectively, while end-systolic LV remained unchanged. In the LV inflow pattern, peak early filling velocity (E) increased substantially (preoperative 31, postoperative 58 cm/sec), with no change in peak late filling velocity (A) (53 cm/sec), which gave a favorable E/A ratio (from 0.58 to 1.09). First-degree AV block resolved after tumor resection (PR interval: 0.23 vs 0.20 sec). Improved LV diastolic function associated with natural recovery from the myxoma was ascribed to the restoration of preload and recovery of systolic function. The results of this study show that removal of a large myxoma in the right atrium is important not only for preventing possible obstruction of the tricuspid orifice, eliminating pulmonary emboli, and maintaining systolic function, but also for restoring LV diastolic function.

Diastole↗

PubMed1995

Detection of high-molecular weight mucin-like glycoprotein-A (HMGP-A) of human milk by chicken egg yolk antibody.

Two high-M(r) mucin-like glycoproteins similar to each other, HMGP-A and C, have been discovered in human milk [Shimizu et al., Biochem. J., 233, 725 (1986)]. To characterize the properties of HMGP-A, specific antibody which is not reactive to HMGP-C was prepared by immunizing hens with HMGP-A. The HMGP-A-specific antibody (IgY) prepared by affinity-purification seems to be useful to distinguish HMGP-A-related antigens in milk and blood sera.

Animals↗

PubMed1995

Stabilization of the tight junction of the intestinal Caco-2 cell monolayer by milk whey proteins.

The tight junction (TJ) of the human intestinal Caco-2-SF monolayer was shown not to have been stably formed. TJ was stabilized by incubating the cell monolayer with beta-lactoglobulin (beta-Lg) and bovine serum albumin (BSA). Thus, the Caco-2-SF cell-culture system will provide a useful model for studying the factors which stabilize TJ and for investigating the mechanism of TJ regulation.

Animals↗

PubMed1995

Effects of freezing on the proteolysis of beef during storage at 4 degrees C.

The effects of freezing on the proteolysis of beef during storage at 4 degrees C after being thawed was investigated. A sarcoplasmic 32-kDa protein in frozen as well as unfrozen beef decreased rapidly during storage at 4 degrees C, and a more than 100-kDa protein appeared in both beef samples. And the increment of peptides in the frozen beef during the storage at 4 degrees C was larger than that in the unfrozen beef, suggesting that the proteolysis was faster during the storage of the former than the latter. However, its increment in the frozen beef for 10 weeks during the storage at 4 degrees C became smaller than that of the one frozen for less than 5 weeks. To discover an indicator for evaluation of the conditioning of frozen and unfrozen beef, peptides produced during the storage of beef at 4 degrees C were surveyed. A peptide, APPPPAEVPEVHEEV, was detected and seemed to be available as an indicator in the conditioning of beef.

Amino Acid Sequence↗

PubMed1995

Synthesis of a peptide emulsifier with an amphiphilic structure.

Three kinds of peptides (H, S, and R) with 16 amino acid residues were synthesized, and their secondary structure and emulsifying properties (emulsifying activity and oil-binding property) were investigated to clarify the effects of conformational amphiphilicity. The amino acid compositions of the three peptides were the same (8 Leu and 8 Glu residues) but their sequences were different. Circular dichroism analysis showed that peptide H contained an alpha-helix at pH 5.5 but took a random structure at pH 7.0. Peptide S also contained an alpha-helix at pH 5.5, while a beta-sheet structure was predominant at pH 7.0. Peptide R took mainly a random structure at both pH 5.5 and pH 7.0. The helical properties of peptide H and peptide S were different; the alpha-helix of peptide H was amphiphilic, while that of peptide S was not. Under conditions where peptide H formed an amphiphilic alpha-helix, both the emulsifying activity and oil-binding property of the peptide significantly increased. The emulsifying properties of peptide S, which formed an amphiphilic beta-sheet at pH 7.0, were also good at that pH. We conclude that a peptide with an amphiphilic alpha-helix or beta-sheet structure has better emulsifying properties, hence a good peptide emulsifier could be designed by incorporating such a structure.

Adsorption↗

PubMed1995

Encapsulation of biologically active proteins in a multiple emulsion.

To improve the stability of IgY antibody in oral administration, encapsulation of IgY in a W/O/W emulsion was attempted. A stable W/O/W emulsion containing 1% IgY was prepared by using polyglyceryl condensed ricinolate (PGCR) and dextran-casein conjugate as the primary and secondary emulsifier, respectively. However, the activity of IgY antibody was reduced to less than 20% by encapsulation, suggesting that denaturation/inactivation of IgY had occurred at the oil/water interface. Adsorption of IgY to the inner water droplet surface was observed by electron microscopy. Rabbit IgG, alpha-amylase, and lysozyme also lost their activity after being encapsulated, although the rate of inactivation was lower than that of IgY. Molecular characterization of these proteins suggested that the rate of inactivation after encapsulation is likely to be dependent on the surface hydrophobicity and molecular stability of each protein.

Adsorption↗

PubMed1995

A canine case of discoid lupus erythematosus with circulating autoantibody.

A nine-year-old Shetland sheepdog was diagnosed as discoid lupus erythematosus by clinical features, histopathologic findings, positive direct immunofluorescence, negative antinuclear antigen test and the absence of multisystemic diseases. The indirect immunofluorescence test of this patient dog with the salt split skin showed the deposition at the bottom of the cleft at basement membrane zone (BMZ). Western immunoblotting revealed the 120 kDa and the 85 kDa proteins targeted by the autoantibody. These proteins did not correspond with the known BMZ component.

Animals↗

PubMed1995

Short-term oral treatment of canine benign prostatic hypertrophy with chlormadinone acetate.

Ten beagle dogs (4-8 years of age) with benign prostatic hypertrophy were treated daily for 7 or 14 days by a daily oral administration of chlormadinone acetate (CMA), an anti-androgenic preparation, at a dose of 0.5 or 2.0 mg/kg/day. The groups of dogs treated with CMA at a dose of 2.0 mg/kg showed a greater reduction of the prostatic volume during 7 or 14 days of treatment than the group treated with 0.5 mg/kg of CMA. At 56 and 84 days after the start of CMA treatment, prostate volume was reduced to 63 and 79% of the pre-administration volume, respectively. No marked decrease in plasma LH or testosterone was found after the CMA treatment. These results indicate that the therapeutic effects of 7-day oral treatment with CMA at 2.0 mg/kg/day in dogs with BPH last for about three months or longer without side effects.

Administration, Oral↗

PubMed1995

Effect of chlormadinone acetate-pellet implantation on the volume of prostate, peripheral blood levels of sex hormones and semen quality in the dog.

Chlormadinone acetate (GS implant, CMA) pellet, a synthetic luteal hormone preparation, was subcutaneously implanted at 5, 10 and 20 mg/kg in four normal male dogs ranging in age from 3 to 10 years to determine the changes in the prostatic volume, peripheral plasma levels of sex hormones and semen quality. The plasma levels of CMA, LH, testosterone (T) and 5 alpha-dihydrotestosterone (DHT) were measured by radioimmunoassay. The prostatic volume was measured by computed tomography. The semen was collected by digital manipulation. The pellet was removed 26 weeks after implantation. The effects of CMA pellet implantation were examined during implantation and until 22 weeks after removal. The prostatic volume was reduced to 61 +/- 3 (mean +/- S.E., n = 4), 52 +/- 5 (n = 4) and 53 +/- 9 (n = 4)% of the preimplantation volumes in the 5, 10 and 20 mg/kg groups, respectively. The plasma CMA levels in the 10 mg/kg and 20 mg/kg groups peaked at 2 weeks, but were gradually decreased. At 22 weeks after removal of the pellet, the prostatic volume returned to 74-85% of the preimplantation volumes. The plasma LH levels tended to increase after implantation in all groups. The plasma T and DHT levels were slightly decreased in all groups. In the 10 and 20 mg/kg groups, the number of sperm and motility sperm was reduced, and the rate of abnormal sperm increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1995

Increased expression of a regenerating (reg) gene protein in neonatal rat pancreas treated with streptozotocin.

We examined the expression of reg protein in neonatal rat pancreas treated with streptozotocin (STZ) by means of the immunohistochemical technique and northern blotting. Seven days after STZ injection, the plasma glucose levels in STZ-treated neonatal rats were significantly higher than those in control rats. Scattered distribution of reg protein in pancreatic islet cells was clearly observed in STZ-treated rats, but not in control rats. On the other hand, reg proteins was positively stained in the exocrine cells in both groups of rats. Northern blot analyses revealed that the expression of insulin mRNA markedly decreased in STZ-treated rat pancreas, but a significant increase in reg mRNA expression was recognized in the STZ-treated rat pancreas compared with that of control rats. Rats treated with STZ during the neonatal period have been used as a model of non-insulin-dependent diabetes mellitus (NIDDM) and beta cell regeneration. Thus, the increased reg gene expression in neonatal STZ-treated rat pancreas was therefore described for the first time, and thus would be a useful model for studying the relationship between NIDDM and beta cell regeneration or reg gene protein.

Animals↗

PubMed1995

Dilated cardiomyopathy defines serum autoantibodies against G-protein-coupled cardiovascular receptors.

In order further to identify the prevalence of anti-receptor autoantibodies in the sera of patients with dilated cardiomyopathy (DCM), we attempted to detect autoantibodies against a series of G-protein-coupled cardiovascular receptors in a well-defined population of DCM patients from Japan. Peptides corresponding to the sequences of the second extracellular loops of the human beta 1 and beta 2 adrenoceptors, alpha 1 adrenoceptors, M2 muscarinic acetylcholine receptors and angiotensin II-1 (AT1) receptors were used as antigens in an enzyme immunoassay to screen the sera from patients with DCM (n = 28). Nine sera from patients with DCM (32%) and 2 sera from healthy subjects (9%) recognized the beta 1 adrenoceptor peptide. Ten sera from patients (36%) and 3 sera from healthy subjects (13%) recognized the M2 receptor peptide. Thirty-six per cent of the patients with autoantibody against the beta 1 adrenoceptor peptide. Ten sera from patients (36%) and 3 sera from healthy subjects (13%) recognized the M2 receptor peptide. Thirty-six per cent of the patients with autoantibody against the beta 1 adrenoceptor had autoantibody against the M2 receptor. However, no significantly high frequencies of autoantibodies against the beta 2 adrenoceptor, alpha 1 adrenoceptor and AT1 receptor were found in DCM patients. Our results demonstrate that a subgroup of patients with DCM have a specific spectrum of autoantibodies which are specifically directed against the second extracellular loops of the beta 1 adrenoceptors and M2 muscarinic receptors rather than other cardiovascular receptors.

Adult↗

PubMed1995

Differentiation of Langerhans cells from interdigitating cells using CD1a and S-100 protein antibodies.

The present study shows that Langerhans cells can be differentiated from interdigitating cells at the light microscopic level. Superficial lymph nodes and skin taken from necropsies and the lymph nodes of dermatopathic lymphadenopathy (DPL) were used for this experiment. Sections of lymph node and skin were embedded using the acetone, methyl benzoate and xylene (AMeX) method and dendritic cells were immunostained with anti S-100 protein antibody (S-100, and OKT-6 (CD1a) using the restaining method. Langerhans cells in the skin were positive for both CD1a and S-100. Dendritic cells positive for both CD1a and S-100, and dendritic cells positive for S-100, but not for CD1a were observed in superficial lymph nodes. In normal superficial lymph nodes, there were more interdigitating cells than Langerhans cells. The majority of the dendritic cells in the DPL were Langerhans cells. We conclude that the S-100 and CD1a positive cells are Langerhans cells, and the S-100 positive-CD1a negative cells are interdigitating cells.

Antigens, CD1↗