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Biomedical subjects

M Nakatani

Publications and source records attributed to M Nakatani.

At least 55 records · Page 3Linked to original sources
PubMed1996

S-methylmethionine sulfonium in fruits of citrus hybrids.

The S-methylmethionine sulfonium (MMS) concentrations in fruits of citrus hybrids were measured, and found to increase during ripening of the fruit. However, there of eleven hybrids of 'Seto unshiu' crossed with 'Morita ponkan' and four of 9 hybrids of 'Murcott' tangor crossed with 'Seto unshiu' had low MMS concentrations even at late harvest stage. Crossbreeding is useful in producing new citrus fruits that have juices with the desirable characteristics of their parents without formation of dimethyl sulfide which is an off-flavor.

Citrus↗
PubMed1996

Death in a dish: controls of apoptosis within the developing retinal tissue.

Studies of programmed cell death in the developing retina in vitro are currently reviewed. The results of inhibiting protein synthesis in retinal explants indicate two mechanisms of apoptosis. One mechanism depends on the synthesis of positive modulators ('killer proteins'), while a distinct, latent mechanism appears to be continuously blocked by negative modulators. Extracellular modulators of apoptosis include the neurotrophic factors NT-4 and BDNF, while glutamate may have either a positive or a negative modulatory action on apoptosis. Several protein kinases selectively modulate apoptosis in distinct retinal layers. Calcium and nitric oxide were also shown to affect apoptosis in the developing retinal tissue. The protein c-Jun was found associated with apoptosis in various circumstances, while p53 seems to be selectively expressed in some instances of apoptosis. The results indicate that the sensitivity of each retinal cell to apoptosis is controlled by multiple, interactive, cell type- and context-specific mechanisms. Apoptosis in the retina depends on a critical interplay of extracellular signals delivered through neurotrophic factors, neurotransmitters and neuromodulators, several signal transduction pathways, and the expression of a variety of genes.

Animals↗
PubMed1995

Chemical stability of polyacrylamide-coating on fused silica capillary.

The chemical stability of polyacrylamide coatings on a fused silica capillary for capillary electrophoresis was investigated with respect to temperature of capillary and pH as well as salt concentration of running buffer solution by evaluating their effects on electroosmotic mobility. The capillary covalently bonded to linear polyacrylamide through Si-C linkage was stable in buffer solutions of pH 2.3-8.0 at 30 degrees C for 30 days, whereas the capillary bonded through Si-O-Si-C linkage was damaged at pH above 4.6. The electroosmotic mobility observed in both capillaries increased with increasing temperature, though the degree of increase was smaller in the Si-C linked capillary than in the Si-O-Si-C linked capillary. The increase in the buffer concentration resulted in increased electroosmotic mobility in the Si-O-Si-C linked capillary, but no effect was observed for the Si-C linked capillary.

Acrylic Resins↗
PubMed1995

Role of basic and acidic fragments in delicious peptides (Lys-Gly-Asp-Glu-Glu-Ser-Leu-Ala) and the taste behavior of sodium and potassium salts in acidic oligopeptides.

The role of the acidic fragment (Asp-Glu-Glu) in delicious peptides was investigated in detail by using the Na+ or K+ salts of acidic oligopeptides so that amount of Na+ or K+ intake of peptides composed of acidic amino acids could be varied by changing their sequences. The taste of these peptides was confirmed to vary with Na+ or K+ intake. Additionally, in order to study the role of basic (Lys-Gly) and acidic (Asp-Glu-Glu) fragments in delicious peptides for producing the taste, five delicious peptide analogs, Ser-Leu-Ala-Lys-Gly-Asp-Glu-Glu, Ser-Leu-Ala-Asp-Glu-Glu-Lys-Gly, Lys-Gly-Ser-Leu-Ala-Asp-Glu-Glu, Lys-Gly-Asp-Glu-Glu, and Glu-Glu-Asp-Gly-Lys, were synthesized. The intensity of the umami and/or salty taste of these peptides and their Na salts was almost the same, despite their chemical structures being different. These results indicate that the acidic fragment as well as the basic fragment plays an important role in the taste production and intensity of delicious peptides, and that an umami or salty taste can be produced by the localization of the cation of the basic fragment and the anion of the acidic fragment.

Amino Acid Sequence↗
PubMed1995

Cultural differences in attitudes, values, and beliefs about osteoporosis in first and second generation Japanese-American women.

This study examines attitudinal differences related to osteoporosis between first and second generation Japanese-American women. In an interview, the women completed a battery of tests assessing their attitudes, values, and beliefs about the diagnosis, treatment, and follow-up care of osteoporosis. The groups differed in their general knowledge of osteoporosis, perceptions of the disease, attributions of its causes, anticipated and preferred support mechanisms for care, and anticipated areas of concern for self-or other-care. There were also considerable differences in treatment compliance and feelings toward physicians. The findings were discussed in relation to the effects of culture on health-care attitudes and behaviors.

Acculturation↗
PubMed1995

[The influence of electrical time interval indices and aging on the left atrial systolic time intervals].

The influence of aging and heart rate on left ventricular systolic time intervals is well known, but the effects on left atrial systolic time intervals, a new index of left atrial function, remain unknown. The influence of aging and heart rate on left atrial systolic time intervals was investigated in 43 normal subjects (13-72 years of age) by Doppler echocardiography. Atrial pre-ejection period, atrial ejection time, and corrected atrial pre-ejection period were obtained by transmitral Doppler echocardiography. Simple regression analysis showed atrial pre-ejection period significantly correlated with P wave duration (PP; r = 0.78), and PR interval (PR; r = 0.60), but not with RR interval (RR). However, multiple regression analysis showed atrial pre-ejection period significantly correlated only with PP. Simple regression analysis found atrial ejection time significantly correlated with PP (r = 0.38), and PR (r = 0.39), but not with RR. However, multiple regression analysis found atrial ejection time did not correlate with any factor significantly. Aging was significantly correlated with corrected atrial pre-ejection period (r = -0.37), but not with corrected atrial ejection time and atrial pre-ejection period. Atrial ejection time significantly correlated with corrected atrial pre-ejection period (r = -0.37), but not with atrial pre-ejection period. Corrected atrial pre-ejection period is a clinically useful index of left atrial systolic function.

Adolescent↗
PubMed1994

High-performance capillary electrophoresis of SDS-proteins using pullulan solution as separation matrix.

Sodium dodecyl sulphate (SDS) capillary electrophoresis using pullulan solution as a separation matrix was developed for the separation and molecular mass determination of proteins. The silanol functions on the inner surface of a fused-silica capillary were deactivated by coating with linear polyacrylamide through Si-C linkages, into which the pullulan solution was filled. The stability of the coating was examined by exposure to an alkaline buffer solution (pH 9.2) for up to 30 days. Compared with conventional coatings with linear polyacrylamide through siloxane linkages, the present capillary was more stable even under alkaline conditions and markedly reduced electroosmotic flow. Thus, polymer solutions of low viscosity such as pullulan solution could be stabilized in the capillary, resulting in a prolonged life-span of the capillary and improved reproducibility of separations. An excellent linear relationship was obtained between the mobility and the logarithm of the molecular mass of SDS-proteins. The relative standard deviation of migration times was below 0.5% when the pullulan solution was refilled in each analysis (n = 10). The calibration plots of the integrated peak areas at 214 nm vs. concentration of standard proteins were linear in the range 5 micrograms/ml-0.1 mg/ml.

Electrophoresis, Polyacrylamide Gel↗
PubMed1994

Preparation and characterization of a stable polyacrylamide sieving matrix-filled capillary for high-performance capillary electrophoresis.

A stable sieving matrix of polyacrylamide filled in a capillary was developed. The inner wall of a fused-silica capillary was covalently bonded with a linear polyacrylamide through Si-C linkages, in which cross-linked polyacrylamide gel or linear polyacrylamide solution was filled. The stability of the coating was examined by exposure of the capillaries to alkaline buffer (pH 8) for up to 30 days. Compared with the coatings with linear polyacrylamide bonded through siloxane linkages, the present capillary markedly reduced the electroosmotic flow. Thus, the sieving matrix in the capillary was stabilized, resulting in a prolonged lifetime of the capillary and good reproducibility of separations. The migration behaviours of oligonucleotides were compared for the cross-linked gel and linear polyacrylamide solution at the same concentration.

Base Sequence↗
PubMed1993

Sodium dodecyl sulfate-polyacrylamide solution-filled capillary electrophoresis of proteins using stable linear polyacrylamide-coated capillary.

Sodium dodecyl sulfate (SDS)-linear polyacrylamide solution-filled capillary electrophoresis using a stable coated fused silica capillary has been developed for the separation and molecular weight determination of proteins. A fused silica capillary was coated with linear polyacrylamide through Si-C bond which suppressed the electro-osmotic flow and reduced the adsorption of proteins. Acrylamide solution containing SDS was filled into the coated capillary and polymerized. Compared with a conventional fused silica capillary coated with 3-methacryloxypropyltrimethoxysilane through siloxane linkage (Si-O-Si-C), the developed capillary was much more stable, even in the alkaline condition. Consequently, the durability of the polymer matrices and the reproducibility of separation were markedly improved. An excellent linear relationship was obtained between the mobility and the logarithm of the protein molecular weight. The relative standard deviation of migration times was below 1%.

Electrophoresis, Polyacrylamide Gel↗
PubMed1993

A new treatment for dialysis-related amyloidosis with beta 2-microglobulin adsorbent column.

Dialysis-related amyloidosis (DRA) is characterized by the presence of beta 2-microglobulin (beta 2-m) in the plasma. In order to eliminate beta 2-m from the circulating blood, the beta 2-m selective adsorbent for direct hemoperfusion (DHP) was developed. A DHP column (BM-01), containing 350 ml of the adsorbent, was subjected to clinical trials. The column was connected with a PAN (AN69) membrane dialyzer in series and used 3 times a week for 1 week (11 patients), 4 weeks (5 patients), 6 months (1 patient) and 12 months (2 patients). The percent reduction (%) of beta 2-m was for 16 patients (for 1 or 4 weeks), more than 65, and for 3 patients (for more than 6 months), 76.5 +/- 4.9, 73.5 +/- 5.7, 72.2 +/- 6.2. At the end of each session, beta 2-m plasma levels were found to be below 10 mg/L, with 3.4 mg/L being the lowest. The total amounts of beta 2-m removed were 172.5 +/- 22.3, 257.0 +/- 75.6, 157.6 +/- 32.2 and 429.8 mg/session at max. Two out of these three patients had a favorable effect on joint symptoms and ocular fundus. It can be concluded that this selective adsorption therapy may delay the progression of DRA, and is worth considering for wide application.

Adsorption↗
PubMed1992

Aspartic acid-66 is the only essential negatively charged residue in the putative hydrophilic loop region of the metal-tetracycline/H+ antiporter encoded by transposon Tn10 of Escherichia coli.

Of the 16 acidic amino acid residues located in the hydrophilic region of the metal-tetracycline/H+ antiporter of transposon Tn10, five glutamic acids and three aspartic acids are conserved among the tetracycline/H+ antiporters of Gram-negative bacteria. When these conserved acidic residues were each replaced by a neutral polar residue, glutamine or asparagine, only the Asp66 substitution mutants completely lost their transport activity. The substitution of Glu274, Asp120, Glu181, or Asp38 caused significant reduction of the transport activity, whereas the substitution of the other three residues had no detectable effect on the activity. These findings led to the conclusion that only Asp66 is essential for the transport function.

Amino Acid Sequence↗
PubMed1992

Metal-tetracycline/H+ antiporter of Escherichia coli encoded by transposon Tn10. Roles of the aspartyl residues located in the putative transmembrane helices.

Three conserved aspartyl residues located in the putative transmembrane helices in the Tn10-encoded metal-tetracycline/H+ antiporter were replaced by Asn, Lys, or Glu with oligonucleotide-directed site-specific mutagenesis. Replacement of Asp84 or Asp15 by Asn or Lys caused a severe defect in tetracycline transport activity, however, the Glu84 and Glu15 mutants retained 150 and 40% of the wild type activity, respectively, indicating the critical role of the negative charge. The increase in the activity of the Glu84 mutant was due to an increase in the affinity for the substrate. H+/tetracycline coupling was intact in these mutants, including Asn and Lys mutants. On the other hand, all of the Asp285-substitution mutants showed a severe defect in tetracycline transport activity and a complete lack of tetracycline-coupled H+ transport. However, since in vivo tests showed the tetracycline resistance for the Glu285 mutant, a negative charge in position 285 plays some role in maintaining the possible down-hill and/or low affinity efflux of accumulated tetracycline from intact cells. Similar work was done for Asp365, and here the Asn and Glu mutants showed decreased but high activity, while the Lys mutant was only marginally active (5%), indicating that a negative charge is not so demanding in position 365, possibly because it is not in the membrane.

Amino Acid Sequence↗
PubMed1992

Adenomyomatosis of the gallbladder: a clinical survey of 30 surgically treated patients.

Thirty patients with adenomyomatosis of the gallbladder (AMG) were operated on between January 1983 and June 1990. They were made up 3.3% of patients who underwent cholecystectomy during the same interval. Of the 30 patients, ages ranged from 22 to 77 years (mean 52.3 years) and the male-to-female ratio was 8:7. Among the macroscopic types, 10 cases of generalized, 12 of segmental (S) and 8 of fundal (F) were noted, and the size of the affected portion in type S (0.8 +/- 0.2 cm, mean +/- SD) was significantly thinner than in other two types (p less than 0.05). Although the main symptom was abdominal pain, the majority of patients with type F had no complaints. Twenty patients (27%) were accompanied by gallstones including cholesterol stones in 60% of cases, and all six cases showing microbes in the bile had gallstones. Only six patients were diagnosed as AMG by preoperative imaging techniques. Other diagnoses comprised 15 of chronic cholecystitis and 3 of suspected gallbladder carcinoma. To identify the expanded Rokitansky-Aschoff sinuses, endoscopic retrograde cholangiography and/or ultrasonography of the abdomen were most useful. No preponderant coexistent lesion other than gallstones was noted. Levels of carcinoembryonic antigen in gallbladder bile in cases of AMG (2.5 +/- 1.5 ng/ml, mean +/- SD) were significantly lower than in gallbladder carcinoma (p less than 0.01). All the patients were easily treated with cholecystectomy, and 24 patients who have been followed up after surgery are doing well.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Left atrial ejection performance in heart failure as assessed by transesophageal Doppler echocardiography].

To investigate the left atrial ejection performance in heart failure, we observed both the transmitral (TMF) and pulmonary venous flow waves (PVF) by transesophageal Doppler echocardiography in 20 patients with heart failure (16 males, 4 females, 56 +/- 13 years old). In 7 of 20 patients, pulmonary capillary wedge pressures (PC) were also obtained within 72 hours after the transesophageal Doppler echocardiographic examinations. A reversal flow on PVF during atrial systole (atrial backward ejection flow) was observed in all of the 20 patients. Corrected atrial pre-ejection period correlated significantly with PC (r = -0.76, p < 0.05), indicating that the period was shortened in accordance with left atrial Starling's law. This period correlated significantly with both the duration and the time velocity integral of atrial backward flow (r = -0.72, p < 0.005; r = -0.55, p < 0.05, respectively), but not with the atrial ejection time nor with the time velocity integral of atrial systole. These results suggest that in some cases of heart failure, left atrial contractile function is preserved despite the marked augmentation of left atrial afterload, resulting in a decrease of the left atrial forward ejection and an increase of the left atrial backward ejection. Thus, the observations of TMF and PVF by transesophageal Doppler echocardiography are useful for assessing the left atrial ejection performance in patients with heart failure.

Adult↗
PubMed1992

[Clinical and echocardiographic evaluation of the effects of atrial defibrillation in patients with idiopathic cardiomyopathy].

To elucidate the effects of atrial defibrillation in patients with idiopathic cardiomyopathy, we clinically and echocardiographically assessed 6 patients with hypertrophic cardiomyopathy (HCM) and 7 patients with dilated cardiomyopathy (DCM). Their mean age was 57 +/- 14 years and the mean duration of their atrial fibrillation (Af) was 47 +/- 29 days. There were no differences in age and the duration of Af between the HCM and DCM groups. We assessed the effects of defibrillation on the NYHA functional classification, heart rate (HR), systolic blood pressure (S-BP), M-mode echocardiographic data (LVDd, LVDs, %FS, LAD) and transmitral pulsed Doppler echocardiographic findings (peak velocity, time-velocity integral of rapid and atrial filling waves). These indices were obtained before and 52 +/- 22 days after defibrillation, and were compared with each other. 1. HR decreased (HCM: 87 +/- 16-->58 +/- 7/min, DCM: 93 +/- 19-->70 +/- 14/min) and total left ventricular filling increased (HCM: 6 +/- 1-->11 +/- 4 cm, DCM: 6 +/- 1-->10 +/- 2 cm) after defibrillation, and the increment of %FS (HCM: 36 +/- 6-->41 +/- 6%, DCM: 16 +/- 6-->25 +/- 11%) was observed. Four of 6 HCM patients and 5 of 7 DCM patients also improved with regard to the NYHA classification. 2. After defibrillation, LVDd increased in HCM (42 +/- 4-->47 +/- 4 mm), but not in DCM. However, LVDs decreased in DCM (52 +/- 9-->44 +/- 12 mm), but not in HCM. We concluded that atrial defibrillation had a beneficial effect on the recovery of the left ventricular function both in HCM and DCM due to the reduction in HR and increase in left ventricular filling. The mode of LV functional improvement after defibrillation varied depending on the state of patient's basal pathophysiology .

Adult↗
PubMed1992

[Blood leukotriene B4 response to endotoxin in fish oil fed rats].

Six-week-old male Wistar rats were given a low fat diet containing 15% cod liver oil (FO; n = 30) or 15% safflower oil (SO; n = 30) for 6 weeks. In the polymorphonuclear leukocytes, arachidonic acid (AA) was significantly lower in the FO group than in the SO group (p < 0.001), and eicosapentaenoic acid (EPA) in the FO group was present in large amounts showing the EPA/AA ratio of 1.76. When lipopolysaccharide (LPS; 10mg/kg) was intraperitoneally injected, white blood cell counts in the blood significantly decreased in both groups (p < 0.001) compared to the controls 2 hours later, and at 4 hours, the counts in the SO group (2,033 +/- 151/mm3) were lower than in the FO group (3,189 +/- 624/mm3), (p < 0.01). In both groups, leukotriene B4 (LTB4) in the whole blood increased at 4 hours following LPS-administration compared to the controls (1,219 +/- 167.3pg/ml in the SO group and 600.0 +/- 109.0pg/ml in the FO group, p < 0.001). It should be noted that the level of LTB4 in the SO group was significantly higher than in the FO group (p < 0.001). Changes of the metabolites including decreased LTB4 production in the arachidonic cascade related to the increase of EPA may play a role in the inhibition of the decrease in white blood cell counts.

Administration, Oral↗