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Biomedical subjects

H Mikami

Publications and source records attributed to H Mikami.

At least 73 records · Page 4Linked to original sources
PubMed1996

Efficient oligonucleotide delivery using the HVJ-liposome method in the central nervous system.

We examined the efficiency and intracellular fate of oligodeoxy-nucleotides (ODN) in the central nervous system (CNS) after delivery with a hemagglutinating virus of Japan (HVJ)-liposome vector in vivo and in vitro. In primary cultured granular cells of the rat cerebellum, application of fluorescein isothiocyanate (FITC)-labeled ODN complexed with HVJ-liposomes in vitro resulted in strong fluorescence localized in nuclei that persisted for > or = 2 wk, in contrast to 3 days with ODN alone. In vivo ODN transfer was attempted by different approaches: infusions into the paraventricular nuclei of the hypothalamus and the lateral cerebroventricle. Injection of FITC-labeled ODN into the hypothalamus by the HVJ-liposome method produced a higher concentration and more persistent fluorescence than did injection of ODN alone. Administration of ODN into the lateral cerebroventricle with HVJ-liposomes yielded more conspicuous and prolonged fluorescence in the periventricular layer, predominantly in cell nuclei. Furthermore, the distribution of fluorescent cells was broader with the HVJ-liposome method. These results indicate that the HVJ-liposome method prolongs the half-life of ODN and concentrates them in cell nuclei. Thus it is an efficient method for ODN transfer and holds promise as a gene delivery method in the CNS.

Animals↗
PubMed1996

Current status of antihypertensive therapy for elderly patients in Japan.

To assess how elderly Japanese hypertensive patients are treated by specialists, we conducted a cross-sectional survey. A total of 1,163 outpatients aged 50 years or older were studied. Hypertension was diagnosed in 939 of these patients, and 827 were receiving drug therapy. The average blood pressure during therapy was 143 +/- 16/81 +/- 10 mmHg. In patients aged 70 years or older, systolic blood pressure during antihypertensive therapy was significantly higher (p < 0.01) and diastolic blood pressure was significantly lower (p < 0.01) than the corresponding values in those aged 50 to 59 years or 60 to 69 years. The calculated mean blood pressures were similar in the different age groups. The rate of monotherapy in the patients aged 70 years or older was 58.8%, which was significantly higher (p < 0.01) than the rates of monotherapy in the other age groups. Calcium channel blockers were prescribed in about 80% of patients, irrespective of age or comorbidity. Of the patients receiving calcium channel blockers, 43.5% were treated with monotherapy. This rate significantly (p < 0.01) increased with advancing age. Diastolic blood pressures were significantly lower (p < 0.05) in patients with stroke and in those with ischemic heart disease, diabetes mellitus, or dyslipidemia, as compared with patients with no comorbidity. Among patients aged 70 years or older, the difference in systolic blood pressure between those with ischemic heart disease and those with no comorbidity was not significant. Blood pressure in elderly hypertensive patients was reduced to a level similar to that in younger patients. The target blood pressure was influenced by the presence of comorbidity. Furthermore, specialists showed a high preference for the use of calcium channel blockers in the management of hypertension.

Activities of Daily Living↗
PubMed1996

[Guidelines on treatment of hypertension in the elderly, 1995--a tentative plan for comprehensive research projects on aging and health-- Members of the Research Group for "Guidelines on Treatment of Hypertension in the Elderly", Comprehensive Research Projects on Aging and Health, the Ministry of Health and Welfare of Japan].

We propose the following guidelines for treatment of hypertension in the elderly. 1. Indications for Treatment. 1) Age: Lifestyle modification is recommended for patients aged 85 years and older. Antihypertensive therapy should be limited to patients in whom the merit of the treatment is obvious. 2) Blood pressure: Systolic BP > 160 mmHg, diastolic BP > 90 approximately 10 mmHg. Systolic BP < age + 100 mmHg for those aged 70 years and older. Patients with mild hypertension (140-160/ 90-95 mmHg) associated with cardiovascular disease should be considered for antihypertensive drug therapy. 2. Goal of Therapy for BP: The goal BP in elderly patients is higher than that in younger patients (BP reduction of 10-20 mmHg for systolic BP and 5-10 mmHg for diastolic BP). In general, 140-160/< 90 mmHg is recommended as the goal. However, lowering the BP below 150/85 should be done with caution. 3. Rate of Lowering BP: Start with half the usual dose, observe at the same dose for at least four weeks, and reach the target BP over two months. Increasing the dose of antihypertensive drugs should be done very slowly. 4. Lifestyle Modification: 1) Dietary modification: (1) Reduction of sodium intake is highly effective in elderly patients due to their high salt-sensitivity. NaCl intake of less than 10 g/day is recommended. Serum Na+ should be occasionally measured. (2) Potassium supplementation is recommended, but with caution in patients with renal insufficiency. (3) Sufficient intake of calcium and magnesium is recommended. (4) Reduce saturated fatty acids. Intake of fish is recommended. (2) Regular physical activity: Recommended exercise for patients aged 60 years and older: peak heart rate 110/minute, for 30-40 minutes a day, 3-5 days a week. (3) Weight reduction. (4) Moderation of alcohol intake, smoking cessation. 5. Pharmacologic Treatment: 1) Initial drug therapy. First choice: Long-acting (once or twice a day) Ca antagonists or ACE inhibitors. Second choice: Thiazide diuretics (combined with potassium-sparing diuretic). 2) Combination therapy. (1) For patients without complications, either of the following is recommended. i) Ca antagoinst + ACE inhibitor, ii) ACE inhibitor + Ca antagonist (or low-dose diuretics), iii) diuretic + Ca antagonist (or ACE inhibitor), iv) beta-blockers, alpha 1-blockers, alpha + beta blockers can be used according to the patho-physiological state of the patient. (2) For patients with complications. Drug(s) should be selected according to each complication. 3) Relatively contraindicated drugs. beta-Blockers and alpha 1-blockers are relatively contraindicated in elderly patients with hypertension in Japan. Centrally acting agents such as reserpine, methyldopa and clonidine are also relatively contraindicated beta-Blockers are contraindicated in patients with congestive heart failure, arteriosclerosis obliterans, chronic obstructive pulmonary disease, diabetes mellitus (or glucose intolerance), or bradycardia. These conditions are often present in elderly subjects. Elderly subjects are susceptible to alpha 1-blocker-induced orthostatic hypotension, since their baroreceptor reflex is diminished. Orthostatic hypotension may cause falls and bone fractures in the elderly.

Aged↗
PubMed1995

Identification of a genetic mutation in a family with fructose-1,6- bisphosphatase deficiency.

Fructose-1,6-bisphosphatase deficiency is an inheritable disorder of gluconeogenesis. Sequence analysis of the cDNA of the fructose-1,6-bisphosphatase mRNA isolated from monocytes from a girl with this disease and her consanguineous parents revealed that the patient and her parents were a homozygote and heterozygotes for an insertion of one G residue at G957GGGG961, respectively. This mutation resulted in translation of a truncated enzyme protein, and the mutant protein showed no fructose-1,6- bisphosphatase activity in an overexpression experiment in Escherichia coli. However, this mutation is located in a region of the amino acid sequence which is not well conserved among mammals. A mutagenized clone was prepared from the normal clone. The extents of substitutions and deletions of the amino acid sequence were predicted to be less in the mutagenized protein than in the mutant protein. This mutagenized clone also expressed no fructose-1,6-bisphosphatase activity, although both of two normal clones from control monocytes and a control liver sample expressed an apparently normal level of fructose-1,6-bisphosphatase activity. Thus, this mutation is concluded to be responsible for fructose-1,6-bisphosphatase deficiency in this patient.

Amino Acid Sequence↗
PubMed1995

Laparoscopic repair of an abdominal hernia using an expanded polytetrafluoroethylene patch secured by a four-corner tacking technique.

An improved technique for performing laparoscopic repair of an abdominal hernia is described herein. To ensure a successful repair, it is most important that adequate tension of the expanded-polytetrafluoroethylene (e-PTFE) patch be achieved, and that the defect be completely covered and securely stapled. Our technique involves tacking the four corners of the patch to the abdominal wall with a 2-0 nylon suture using a straight needle, then stapling it to the anterior abdominal wall over the defect with a laparoscopic stapler. We believe that this technique is a safe and reliable method which will prove useful for laparoscopic surgery.

Hernia, Ventral↗
PubMed1995

Prenatal diagnosis and therapy for a patient with vitamin B12-responsive methylmalonic acidaemia.

The prenatal therapy is described of a patient with vitamin B12-responsive methylmalonic acidaemia during the last 10 days of gestation with oral administration of vitamin B12 (20 mg/day) given to a mother did not normalize her urinary excretion of methylmalonic acid (MMA), which was 14.5 mmol/mol creatinine at 32 weeks of gestation. Before delivery, the mother was excreting 18.9 +/- 3.3 mmol MMA/mol creatinine (mean value at 7 days after vitamin B12 therapy), as well as at 32-37 weeks of gestation with no therapy. After birth, the level of MMA in the infant's urine was remarkably elevated (500-700 mmol/mol creatinine); the level of MMA in maternal urine decreased dramatically after delivery. Compared with two previous reports, the length of administration was not sufficient to reduce maternal MMA excretion. In future, the length of the therapy, route of administration and total dose of vitamin B12 to maintain an efficient level of vitamin B12 in an affected fetus should be considered.

Female↗
PubMed1995

Amino acids in the medulla oblongata contribute to baroreflex modulation by angiotensin II.

We investigated the underlying mechanisms of baroreflex alteration produced by intravenous angiotensin II (ANG II) by monitoring the release of amino acids from the rostral ventrolateral medulla (VLM) using a brain microdialysis technique. Reflex changes in heart rate were elicited by bolus intravenous injection of phenylephrine (2-40 micrograms/kg) before and 120 min after the initiation of administration of a subpressor dose of ANG II (5.4 pmol/kg/min) or vehicle. The slope of the regression line obtained from changes in mean arterial pressure and heart rate elicited by phenylephrine was used as an index of baroreceptor reflex sensitivity. ANG II administration for 120 min significantly attenuated the baroreflex sensitivity (from -0.59 +/- 0.10 to -0.30 +/- 0.08 bpm/mmHg). This attenuation was accompanied with an increase in the release of glutamate and glycine from the VLM (+40% and +20%, respectively) at 120 min. Glycine perfusion into this area resulted in an attenuation of baroreflex sensitivity with a magnitude similar to that obtained with infusion of a subpressor dose of ANG II, whereas glutamate perfusion caused a resetting of baroreflex. These results suggest that glycine and glutamate are involved in cardiovascular regulation in the VLM. Furthermore, the augmented releases of these amino acids may account for the underlying mechanism of ANG II-induced attenuation of baroreflex function.

Amino Acids↗
PubMed1995

Enhancement of insulin sensitivity by troglitazone lowers blood pressure in diabetic hypertensives.

The association of hypertension with insulin resistance has been reported. Troglitazone (CS-045) is a newly developed antidiabetic agent that enhances insulin sensitivity. Its antidiabetic effects have been confirmed in diabetic animals and patients. The present study was performed to evaluate whether the amelioration of hyperinsulinemia by troglitazone lowers blood pressure in essential hypertensives. Troglitazone was administered orally to 18 outpatients with essential hypertension complicated by mild diabetes at a dose of 200 mg twice a day for 8 weeks. Blood pressure was decreased from 164 +/- 3/94 +/- 2 mm Hg to 146 +/- 3 (P < .001)/82 +/- 3 (P < .05) mm Hg at 8 weeks of the treatment period. Pulse rate did not change. Fasting plasma glucose changed from 159 +/- 10 mg/dL to 144 +/- 14 mg/dL at 8 weeks (P < .05). Plasma insulin (IRI) levels changes from 9.1 +/- 1.2 microU/mL to 6.3 +/- 0.8 microU/mL at the endpoint of treatment (P < .1). Decrease in mean blood pressure from the control period to the endpoint of the treatment correlated significantly with decrease in IRI (r = 0.59, P < .05). In summary, troglitazone treatment induces improvement in both glucose metabolism and blood pressure control in essential hypertensive patients with diabetes mellitus. These results suggest that insulin resistance or plasma insulin level plays a role in the pathogenesis of essential hypertension.

Aged↗
PubMed1995

Persistent inhibition of the pressor and aldosterone responses to angiotensin-II by TCV-116 in normotensive subjects.

TCV-116 is an orally active, nonpeptide antagonist of angiotensin-II type-1 receptor. The angiotensin-II antagonistic potency of TCV-116 was evaluated in normal volunteers. TCV-116 was administered at single doses of 1, 2.5, and 5 mg orally on separated days. Before, and 4, 8, and 24 h after the drug administration, angiotensin-II was infused intravenously at the rate of 2.5 to 40 ng/kg/min for 5 min each. At 2.5 mg of TCV-116, the pressor response to angiotensin-II was significantly suppressed at 4 and 8 hours after drug administration. TCV-116 at 5 mg produced a reduction of basal blood pressure and a suppression of pressor response to angiotensin-II, which persisted for 24 h. Aldosterone response to exogenous angiotensin-II was suppressed to 10% at 8 h after 5 mg of TCV-116 administration and remained suppressed to 48% until 24 h. These results suggest that TCV-116 is a highly potent and long-lasting antagonist of angiotensin-II receptor in man. The renin-angiotensin system may play a role in the regulation of blood pressure even in normotensive subjects.

Administration, Oral↗
PubMed1995

Assignment of the uteroferrin gene (ACP5) to swine chromosome 2q12-->q21 by fluorescence in situ hybridization.

A cosmid clone containing the uteroferrin gene (ACP5) was selected from a cosmid library of swine genomic fragments by colony hybridization using uteroferrin cDNA as a probe. The genomic fragment thus cloned was examined by Southern blot and sequence analysis which demonstrated that it contained at least a part of the uteroferrin gene. The cosmid clone DNA was labeled with biotin, and used a probe for in situ hybridization to swine chromosomes. Hybridization was visualized by the FITC-labeled streptavidin/biotinylated antistreptavidin system together with R-banding of chromosomes. The hybridization signals revealed that the uteroferrin gene (ACP5) is located on swine chromosome 2q12-->q21.

Acid Phosphatase↗
PubMed1995

Enhanced predictability of myocardial infarction in Japanese by combined genotype analysis.

To explore the genes responsible for myocardial infarction and restenosis after percutaneous transluminal coronary angioplasty, we performed association studies of the polymorphisms of the angiotensinogen and angiotensin-converting enzyme (ACE) genes. In the first study, normotensive myocardial infarction patients (n = 103) and control subjects (n = 103), who were matched for established risk factors with the myocardial infarction patients, were randomly selected. The angiotensinogen-TT genotype (T indicates threonine instead of methionine at position 235) was more frequent in the myocardial infarction group than in the control group (P < .05). The ACE-DD genotype (D indicates a deletion polymorphism in intron 16) was also more frequent in the myocardial infarction group (P < .0001). The odds ratio estimated by the combined analysis of the angiotensinogen-TT and ACE-DD genotypes (11.2) was markedly increased compared with that estimated separately from the angiotensinogen-TT (1.75) or ACE-DD (4.43) genotype. In the second study, we investigated 91 consecutive patients with acute myocardial infarction who underwent successful direct angioplasty. Combined analysis showed that the angiotensinogen-TT genotype did not enhance the predictability of myocardial infarction from the ACE-DD genotype. In conclusion, the angiotensinogen-TT genotype is a predictor for myocardial infarction, as well as the ACE-DD genotype, and the combined analysis of the angiotensinogen-TT and ACE-DD genotypes further enhanced the predictability of myocardial infarction in Japanese, suggesting its future clinical usefulness.

Angioplasty, Balloon, Coronary↗
PubMed1995

Transient decrease in high blood pressure by in vivo transfer of antisense oligodeoxynucleotides against rat angiotensinogen.

The renin-angiotensin system plays an important role in blood pressure regulation. Angiotensinogen, which is mainly produced in the liver, is a unique component of the renin-angiotensin system, because angiotensinogen is only known as a substrate for angiotensin I generation. It is unclear whether circulating angiotensinogen is a rate-limiting step in blood pressure regulation. Recent findings of genetic studies and analyses suggest that the angiotensinogen gene may be a candidate as a determinant of hypertension. To test the hypothesis that angiotensinogen may modulate blood pressure, we transfected antisense oligonucleotides against rat angiotensinogen into the rat liver via the portal vein using liposomes that contain viral agglutinins to promote fusion with target cells, a technique that has been reported to be highly efficient. Transfection of antisense oligonucleotides resulted in a transient decrease in plasma angiotensinogen levels in spontaneously hypertensive rats from day 1 to day 7 after the injection, consistent with the reduction of hepatic angiotensinogen mRNA. Plasma angiotensin II concentration was also decreased in rats transfected with antisense oligonucleotides. Moreover, a transient decrease in blood pressure from day 1 to day 4 was observed, whereas transfection of sense and scrambled oligonucleotides did not result in any changes in plasma angiotensinogen level, blood pressure, or angiotensinogen mRNA level. Overall, our results demonstrate that transfection of antisense oligonucleotides against rat angiotensinogen resulted in a transient decrease in the high blood pressure of spontaneously hypertensive rats, accompanied by a decrease in angiotensinogen and angiotensin II levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1995

Gap junction protein locus on chromosome 18 cosegregates with body weight in the spontaneously hypertensive rat.

To detect genetic predisposing factors for hypertension, we screened the genome of the spontaneously hypertensive rat (SHR). We determined the genotypes of all F2 rats at polymorphic sites between the two strains, using the DNA of F2 rats derived from mating of SHR and Wistar-Kyoto rats (WKY). Cosegregation analysis was conducted to assess whether the genotypes of polymorphic markers associate with any phenotypic parameters such as directly measured blood pressure, heart rate or body weight. All measurements in F2 rats were performed at 15 weeks of age. Two polymorphic markers on chromosome 18 cosegregated with body weight. Gap junction protein (heart connexin 43) gene showed the most significant association with body weight as a recessive trait, but no association was noted with other parameters. We conclude that the gap junction protein locus is a new candidate for the determinant gene of body weight in SHR.

Analysis of Variance↗
PubMed1995

Hormonal mechanisms in blood pressure reduction during hemodialysis in patients with chronic renal failure.

To elucidate the hormonal mechanisms of blood pressure (BP) reduction during hemodialysis in patients with chronic renal failure (CRF), we performed this study using 7 normotensive (NT) and 17 hypertensive (HT) patients who were strictly matched in age, body weight, body weight gain from the last HD, and duration of HD. Blood pressure, pulse rate, plasma norepinephrine (NE), and plasma dopamine levels were used as indices of sympathetic nerve activity, before, at 50% of hemodialysis (HD) and at 100% of HD (at the end of HD) on the third day after the last HD. As hemodialytic BP reduction was defined as BP decline of more than 10% in pre-HD mean BP, in normotensive patients with CRF, hemodialytic BP reduction was recognized in 0/7 (0%) at 50% of HD and 4/7 (57%) at 100% of HD, and in hypertensive patients it was recognized in 3/17 (18%) at 50% of HD and 4/17 (24%) at 100% of HD. Percentile changes in plasma NE levels increased slightly following hemodialysis in normotensive patients with hemodialytic BP reduction and in hypertensives without BP reduction, while those in normotensives without BP reduction and in hypertensives with BP reduction did not change. However, percentage changes in plasma dopamine (DA) levels decreased significantly at the end of HD (NT; p < 0.05, HT; p < 0.01) following hemodialysis in both normotensive and hypertensive patients with hemodialytic BP reduction, while changes in patients without BP reduction, percentage changes in DA did not change (patients with BP reduction vs. patients without BP reduction). In conclusion, hemodialytic BP reduction may be predisposed by abnormal sympathetic nerve responsiveness.

Adult↗
PubMed1995

[Perceived quality of life and social factors in elderly hypertensive patients].

We conducted a cross-sectional study of elderly outpatients with hypertension to examine the relationship between quality of life (QOL) scores and social background factors. The subjects consisted of 516 outpatients (267 females), age of 60 or over, at nine clinics of major hospitals which participated in the National Cardiovascular Center Research Project. The perceived QOL was evaluated by the QOL scale originally based on Japanese patients with cardiovascular diseases. The scale consisted of the following 5 subscales; difficulty due to disease, psychological stability, independence, satisfaction in daily living and vitality. The background factors included family structure, socioeconomic factors and work status, and physical activity of daily living (ADL). After adjusting for age, sex, administered drugs and complicating conditions such as ischemic heart disease and/or apoplexy, a significant odds ratio of a low score of difficulty due to disease, psychological stability, satisfaction in daily living and vitality was found in the impaired physical ADL group with low socioeconomic class, and a significant odds ratio of low score of independence were found in the impaired physical ADL group who had lost jobs due to illness and had no children.

Aged↗
PubMed1995

[Age estimation by appearance of gray hair in pubic hair].

The pubic hair of Japanese males aged 12-90 years old (n = 123) and females 14-85 ys. (n = 80) autopsied during 1984-1993 was investigated to determine its appearance age and possible appearance age of gray hair. As the appearance degree of gray hair in pubic hair 5 stages were applied to samples to establish a criterion for age estimation. Stage 0; no gray hair, 1; 1-3 gray hairs, 2; a few-10, 3; 10 gray hairs-2/3 of the entire pubic hair, 4; more than 3/4. The appearance age of gray hair with appearance rate 100% (75%) was more than 65 (55) ys. in both sex. The possible appearance age was more than 30 ys. in males and 36 ys. in females, practically younger than "45 years old" which had been described in texts. The age range with a hit rate 100% is at stage 0; less than 62 ys. in males, less than 59 ys. in females, at stage 1; 30-64 ys. in males, 36-60 ys. in females, at stage 2; 43-72 ys., 39-85 ys. and at stage 3; 49-77 ys,--.

Adolescent↗
PubMed1995

[Relationship among "kenshi" (inquest), "kenshi" (postmortem examination) and "ken-an" (postmortem inspection) in Japan].

Inquest ([symbol: see text]) and postmortem examination ([symbol: see text]) have the same pronunciation of "kenshi" in Japan. So we are inclined to use these terms with confusion or substitution. We discussed the differences among three "kenshis" adding to postmortem inspection ([symbol: see text]; "ken-an") with investigating references. Many forensic scientists described that inquests were done by public prosecutors and inspections by medical doctors. But there were various interpretations of postmortem examination, e.g. "postmortem examination is done by public prosecutors or police", "it is the same as inspection by medical doctor", "it is one of the aids of inquest", "it is also including forensic autopsy". Although being no differences between the two kenshis written by two kinds of different Chinese characters ([symbol: see text]). This is caused an only problem in writing Japanese languages, it happens especially when we have to use Chinese characters for everyday use. In order to define this postmortem examination in Japan, we paid attention to corpse procedures. We made a figure to include each interpretation and to understand that postmortem examination had several meanings from a narrow sense to a wide sense. We suggested that the most confident definition was of the widest sense which meant the inspection and autopsy by doctors and the inspection by public prosecutors or police.

Forensic Medicine↗