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Biomedical subjects

M Shimizu

Publications and source records attributed to M Shimizu.

At least 181 records · Page 10Linked to original sources
PubMed2001

[Whole blood flow cytometry for detection of activated platelets. I. Platelet identification, blood collection and storage].

In order to assess platelet activation by flow cytometry and activation-dependent monoclonal antibodies, a minute volume(2.5 microliters) of citrated whole blood was mixed for 15 minutes with a cocktail of monoclonal antibodies(MoAb), including PAC1, (a MoAb specific for fibrinogen receptors), and a MoAb against CD62P, (an alpha-granule membrane protein which associates with platelet surface membranes when platelets are activated). After fixation with 1% formaldehyde, the percentage of platelets positive for PAC1 and/or MoAb-CD62P was measured by flow cytometry. Even in resting platelets without stimulation, about 15% of platelets were found to be PAC1-positive and 0.6% of platelets were CD62P-positive. If there was a one-minute delay after needle puncture and before blood collection, the number of PAC1-positive platelets was increased compared to that of blood obtained immediately after puncture. If blood was allowed to stand at room temperature, there was a gradual increase in the number of PAC1-positive platelets, and after 60 minutes, this increase became statistically significant. The addition of Iloprost, (a prostacyclin analogue), immediately after venipuncture did not completely prevent the increase in PAC1-positive platelets after 60 minutes. If the inhibitor was added after first incubating for 60 minutes, however, the percentage of PAC1-positive platelets was reduced to preincubation value. Although flow cytometry is a simple and powerful tool to assess platelet activation, there remain several methodological problems to be resolved before this method may be employed in routine clinical use.

Adult↗
PubMed2001

Effect of prolonged low-dose methylprednisolone therapy in acute exacerbation of idiopathic pulmonary fibrosis.

We report on a 74-year-old man with an acute exacerbation of idiopathic pulmonary fibrosis (IPF) who was successfully treated with prolonged low-dose methylprednisolone, initiated at a loading dose of 2 mg/kg, followed by 2 mg/kg per day for 14 days. The dose was then tapered. The exacerbation observed on the chest radiograph and high-resolution computed tomography was found to have abated after the treatment. This successful case suggests the feasibility of this methylprednisolone treatment protocol for patients with IPF accompanied by accelerated deterioration. Furthermore, this case suggests possible similarities between acute exacerbation of IPF and late acute respiratory distress syndrome, as the same treatment protocol was previously proved to be beneficial for patients with late acute respiratory distress syndrome.

Acute Disease↗
PubMed2001

[Changes in serum malondialdehyde-modified low-density lipoprotein in patients with acute myocardial infarction and stable angina pectoris treated by coronary angioplasty].

OBJECTIVES: Serum malondialdehyde-modified low-density lipoprotein(MDA-LDL) was measured as a marker of oxidative stress, and the changes in serum MDA-LDL compared in patients with acute myocardial infarction and stable angina pectoris treated by percutaneous transluminal coronary angioplasty (PTCA). METHODS: Forty-one patients with acute myocardial infarction or stable angina pectoris were admitted to our hospitals between January 2000 and June 2000. Direct PTCA was performed in 17 patients(MI group) and elective PTCA in 24 patients(AP group). Coronary angiography was performed in nine control subjects(control group). Serum MDA-LDL was measured in the peripheral venous blood before and immediately after procedures in each group(normal range 20-80 U/l). RESULTS: There were no significant differences in patient characteristics, except age, between the MI group and AP group. Serum MDA-LDL was elevated above the normal range before the procedure in both groups(MI group 104.7 +/- 52.0 U/l, AP group 99.7 +/- 42.8 U/l), and significantly decreased immediately after the procedure(MI group 61.3 +/- 25.6 U/l, AP group 62.0 +/- 29.6 U/l), but there were no significant differences between the two groups. Serum MDA-LDL was elevated before the procedure (99.3 +/- 48.9 U/l) in the control group and significantly decreased immediately after the procedure(61.7 +/- 26.2 U/l). However, these values did not differ from the values before and immediately after the procedure in the MI group and the AP group. The percentage changes in serum MDA-LDL before and immediately after the procedure were -38 +/- 16% in the MI group, -37 +/- 17% in the AP group and -36 +/- 20% in the control group, and there were no significant differences between the three groups. CONCLUSIONS: No significant difference in the changes in serum MDA-LDL was observed between patients with acute myocardial infarction and stable angina pectoris treated by PTCA. However, anticoagulants may affect the MDA-LDL measurements directly, because similar changes in serum MDA-LDL were observed in control subjects after only coronary angiography.

Age Factors↗
PubMed2001

[Follow-up study of myasthenia gravis: evaluation of thymectomy in 300 patients].

From June 1975 to March 1999, 300 patients of myasthenia gravis(MG) have undergone thymectomy. Among these patients, 69 cases were classified as ocular type of MG(including 15 cases with thymoma), and 231 were generalized type of MG(including 86 cases with thymoma). The efficacy of the treatment was investigated by evaluating current patients' life activity, which is classified in 6 groups(Remission, Much Improved, Improved, Unchanged, Worse, and Died). Among the 214 cases without thymoma, Remission was 75, Much Improved was 56, and Improved was 55, namely 86.9% of these cases showed Improved or better. Among 86 cases with thymoma, Remission was 14, Much Improved was 21, and Improved was 32, namely 77.9% of these cases showed Improved or better. We concluded that post-operative outcome of these patients regardless of thymoma were generally satisfactory, but it was necessary to carry out long term careful follow-up.

Adolescent↗
PubMed2001

The Native Hawaiian Health Professions Scholarship program's impact on the community of Ko'olau Loa: a program report.

The Native Hawaiian Health Professions Scholarship was established as one component of the Native Hawaiian Health Care Act of 1988, which was later reauthorized as the Native Hawaiian Health Care Improvement Act of 1992. The Scholarship program was designed to develop Native Hawaiian primary health care professionals who would return to work in Native Hawaiian communities. To ensure this, scholarship recipients fulfill their scholarship agreement by working in medically unserved and underserved communities throughout Hawai'i. Since 1991, 121 scholarships have been awarded to Native Hawaiians training in different primary care professions including medicine, dentistry, nursing, midwifery, social work, and public health. Although the service obligation is attached to the scholarship as a means of "paying back," the intent is to provide an opportunity for graduates to establish a sense of social responsibility for the communities most in need. One of the communities benefiting from this program is Ko'olau Loa, a community that spans from Ka'a'awa to Pupukea on Windward O'ahu. Native Hawaiian Health Scholarship recipients, Kehau Santiago, Michele Shimizu, and Stephany Vaioleti live and continue to serve in the very community in which they fulfilled their service obligations. This article focuses on how the Native Hawaiian Health Scholarship Program--in particular, the three scholars--affected Ko'olau Loa.

Education, Professional↗
PubMed2001

[Osteoporotic limb fractures].

Osteoporotic limb fractures often result in inadequate reduction, delayed bone union, and joint contracture with reduced patients' activity of daily living (ADL), since they usually occur at the metaphysis. To treat comminuted fractures in patients with severe osteoporosis is difficult. Intramedullary nail and external fixation are used for the treatment of those fractures. Recently calcium phosphate bone cement is available for the fracture treatment.

English Abstract↗
PubMed2000

Particle control of emulsion by membrane emulsification and its applications.

Particle-size control of emulsion is very important for maintaining stability and giving emulsions new functional roles. Porous glass membrane, prepared by phase separation of a glass composition, is available as an emulsifying element, from which, one can obtain monodispersed emulsion with different particle sizes, and useful water/oil/water (W/O/W) emulsion in very high yield. The authors have called this new technology 'membrane emulsification'. Applications of membrane emulsification technology to drug delivery systems were carried out under cooperative research with Miyazaki Medical College. It was found that the clinical administration of a W/O/W drug emulsion that encapsulated an anticancer drug in its inner droplets was surprisingly effective for both terminal and multiple nodules of hepatocellular carcinoma when the drug was injected to damaged liver through a catheter inserted in the hepatic artery. Other applications have been tried and developed elsewhere.

Animals↗
PubMed2000

Factors associated with preventable out-of-hospital nontraumatic cardiac arrest.

To identify ways to decrease the risk of out-of-hospital cardiac arrest (CA) caused by an acute coronary syndrome, we examined factors associated with the development of CA > or = 1 hour after symptom onset. Multivariate analysis revealed that a low level of physical activity, a history of diabetes mellitus, and a history of unstable angina are associated with out-of-hospital CA occurring > or = hour after symptom onset.

Adult↗
PubMed2000

In vitro culture of bovine preantral follicles.

Bovine preantral follicles (40-100 microm diameter at collection) were collected from ovaries of slaughtered cows and cultured in vitro with one of the four treatments: follicle stimulating hormone (FSH; 100 ng/ml) alone; FSH plus epidermal growth factor (EGF; 100 ng/ml); FSH plus insulin-transferrin-selenium (ITS; +1%) or FSH plus hypoxanthine (4 mM) in tissue culture medium (TCM 199) supplemented with 10% fetal calf serum (FCS), 0.1 mg/ml sodium pyruvate, 100 IU/ml of penicillin and 100 microg/ml streptomycin. The control culture medium was TCM 199 with supplements without any treatments. Follicles of each size were cultured separately in groups of one to three in 24-well multidishes each containing 500 microl of the appropriate culture medium. Culture commenced at follicle recovery (day 1) and continued for 10 days (harvested on day 11). In each case, half the medium was removed and replaced by fresh medium every third day. Follicle diameters were recorded on days 1, 5 and 11 of the experiment. At the end of the 10-day culture period, half of the follicles were stained with trypan blue to assess their potential viability and half were stained with bisbenzimide plus propidium iodine to estimate various morphological features of the follicles. Follicles of all initial sizes, on all culture treatments, increased in diameter during in vitro cultures with the greatest increases, both in absolute and proportional size, occurring between days 1 and 5 of culture. All of the culture medium supplements caused greater increases in follicle diameters than control medium at both days 5 and 11 of culture for all initial sizes of follicles (p<0.01). The most effective culture supplements for follicles of 40-, 60- and 80-microm initial diameter were FSH alone and FSH+EGF. The size of these follicles at both days 5 and 11 of culture on both the treatments was significantly larger (p<0.01) than follicles cultured in the presence of the other two supplementary treatments. The growth of follicles of 100-microm initial diameter did not differ between culture medium supplements. None of the culture media caused follicle size to increase to the initial diameters of the next larger size category during the 10 days of culture although follicles of 100-microm diameter achieved a diameter of 120 microm, after 4 days of culture. The overall follicular viability and morphology were better with treatments than the controls in all cases; however, there was no significant difference (p>0.05) among them. From this experiment, FSH and FSH plus EGF may be recommended for in vitro culture of smaller (40, 60 and 80 microm) follicles.

Animals↗
PubMed2000

Factors affecting the survivability of bovine oocytes vitrified in droplets.

Vitrification of bovine oocytes performed using the traditional, in straw system has not given satisfactory results. Although an alternative approach based on minimizing the volume of the vitrified sample has recently resulted in a much more promising survival rate of vitrified oocytes, we attempted to examine some additional factors influencing the survival and subsequent fertilization and development rates of bovine oocytes subjected to vitrification according to the minimum drop size approach. In total, 748 bovine, in vitro matured oocytes were vitrified using VS14 vitrification solution, containing 5.5-M ethylene glycol and 1.0-M sucrose after different pre-equilibration and equilibration protocols performed at 35 degrees to 37 degrees C. Experiment 1 showed no significant toxic effect during pre-equilibration treatments of oocytes in 2%, 4% or 6% ethylene glycol solutions, except the lower cleavage rate of oocytes exposed to 6% ethylene glycol (77.2% vs. 93.9% in control, P< 0.05). In Experiment 2, 12 to 15 min of pre-equilibration treatments in 0%, 1% or 2% ethylene glycol solutions were tested, followed by 30 or 45 sec of equilibration in VS 14 solution and vitrification in droplets of medium dropped directly into liquid nitrogen. The development rate of vitrified oocytes to the blastocyst stage tended to be higher after 30-sec equilibration treatment (9.5%, 13.9% and 13.8% in groups of oocytes pre-equilibrated in 0%, 1% or 2% ethylene glycol solutions, respectively). Experiment 3 tested pre-equilibration treatments in 0%, 1%, 2%, 3%, 4%, 5% or 6% ethylene glycol solutions, followed by 30-sec equilibration and vitrification in droplets. The highest cleavage, blastocyst and hatched blastocyst rates, which were not significantly different from control, were achieved in a group of oocytes pre-equilibrated in 3% ethylene glycol solution (76%, 30% and 15% vs. 89%, 42% and 21% in control, respectively). A healthy calf was born on Feb 22 1999, after transfer of 4 morula/blastocyst stage embryos developed from oocytes vitrified in droplets after pre-equilibration in 3% ethylene glycol solution. We conclude that gentle pre-equilibration of bovine oocytes in diluted, 3% ethylene glycol solution is an important factor improving the effectiveness of vitrification in droplets of bovine oocytes.

Animals↗
PubMed2000

Modifying effects of ferulic acid on azoxymethane-induced colon carcinogenesis in F344 rats.

The modifying effects of dietary administration of ferulic acid (FA) on azoxymethane (AOM)-induced colon carcinogenesis were examined in three experiments with male 344 rats. In the first experiment, the modifying effect of FA on AOM (15 mg/kg body weight, once a week, for 3 weeks)-induced formation of aberrant crypt foci (ACF) was examined in five groups. Numbers of ACF/colon of groups 2 (AOM+250 ppm FA) and 3 (AOM+500 ppm FA) at the termination (5 weeks after the start) were smaller than of group 1 (AOM alone). Those of ACF/cm(2) of group 3 were also smaller than of group 1 (P<0.05). In the second experiment, a long-term assay for the effects of FA was conducted with seven groups. At the termination (35 weeks), groups 2 and 3 which were given FA during the initiation phase at doses of 250 and 500 ppm, respectively, had lower incidences of colonic carcinomas (23 and 27%, respectively) than group 1 which was given AOM alone (59%; P<0.05). In the third experiment, to determine whether FA could modify the activities of phase II detoxifying enzymes, glutathione S-transferase (GST) and quinone reductase (QR) in liver and colon, 60 rats were gavaged with FA at four doses (0, 25, 50, 100 mg/kg body weight). Dosing of 100 mg/kg significantly elevated GST activity in liver (P<0.03), and QR activities in liver and colonic mucosa (P<0.01 and P<0.02, respectively), suggesting that detoxifying enzymes are related to the blocking effect of FA on AOM-induced colon carcinogenesis.

Animals↗
PubMed2000

Clinical features of hypertrophic cardiomyopathy caused by a Lys183 deletion mutation in the cardiac troponin I gene.

BACKGROUND: Mutations that cause hypertrophic cardiomyopathy (HCM) have been identified in 9 genes that code proteins in the sarcomere. Previous reports have demonstrated that cardiac troponin I (cTnI) gene mutations may account for familial HCM; however, the clinical characteristics and prognosis of patients with HCM caused by cTnI gene mutations are not known. METHODS AND RESULTS: We analyzed cTnI gene mutations in 130 unrelated probands with HCM and their families to clarify the genotype-phenotype correlations. We identified 25 individuals in 7 families with a Lys183 deletion (Lys183 del) mutation in exon 7 of the cTnI gene. The disease penetrance in subjects aged >20 years was 88% by echocardiography and 96% by ECG. Sudden death occurred in 7 individuals of 4 families at any age. Overall, 7 (43.8%) of 16 individuals aged >40 years had left ventricular systolic dysfunction, and 3 (18.8%) displayed dilated cardiomyopathy-like features. Of affected individuals, 4 of 5 individuals aged >40 years followed by echocardiography showed septal thinning and decreased fractional shortening during >5 years of follow-up. CONCLUSIONS: The Lys183 del mutation in the cTnI gene in patients with HCM is associated with variable clinical features and outcomes. HCM caused by the Lys183 del mutation has a significant disease penetrance. This mutation is associated with sudden death at any age and dilated cardiomyopathy-like features in those aged >40 years. However, it remains unclear whether screening of families with HCM for this mutation will be useful in patient management and counseling.

Adolescent↗
PubMed2000

Minimization of parathyroid hormone. Novel amino-terminal parathyroid hormone fragments with enhanced potency in activating the type-1 parathyroid hormone receptor.

The amino-terminal and carboxyl-terminal portions of the 1-34 fragment of parathyroid hormone (PTH) contain the major determinants of receptor activation and receptor binding, respectively. We investigated how the amino-terminal signaling portion of PTH interacts with the receptor by utilizing analogs of the weakly active fragment, rat (r) PTH(1-14)NH(2), and cells transfected with the wild-type human PTH-1 receptor (hP1R-WT) or a truncated PTH-1 receptor which lacked most of the amino-terminal extracellular domain (hP1R-delNt). Of 132 mono-substituted PTH(1-14) analogs, most having substitutions in the (1-9) region were inactive in assays of cAMP formation in LLC-PK1 cells stably expressing hP1R-WT, whereas most having substitutions in the (10-14) region were active. Several substitutions (e.g. Ser(3) --> Ala, Asn(10) --> Ala or Gln, Leu(11) --> Arg, Gly(12) --> Ala, His(14) --> Trp) enhanced activity 2-10-fold. These effects were additive, as [Ala(3),(10,12),Arg(11), Trp(14)] rPTH(1-14)NH(2) was 220-fold more potent than rPTH(1-14)NH(2) (EC(50) = 0.6 +/- 0.1 and 133 +/- 16 micrometer, respectively). Native rPTH(1-11) was inactive, but [Ala(3,10), Arg(11)]rPTH(1-11)NH(2) achieved maximal cAMP stimulation (EC(50) = 17 micrometer). The modified PTH fragments induced cAMP formation with hP1R-delNt in COS-7 cells as potently as they did with hP1R-WT; PTH(1-34) was 6,000-fold weaker with hP1R-delNt than with hP1R-WT. The most potent analog, [Ala(3,10,12),Arg(11), Trp(14)]rPTH(1-14)NH(2), stimulated inositol phosphate production with hP1R-WT. The results show that short NH(2)-terminal peptides of PTH can be optimized for considerable gains in signaling potency through modification of interactions involving the regions of the receptor containing the transmembrane domains and extracellular loops.

Animals↗