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Biomedical subjects

K Ichihara

Publications and source records attributed to K Ichihara.

At least 91 records · Page 5Linked to original sources
PubMed1997

Determination of reference intervals for 13 plasma proteins based on IFCC international reference preparation (CRM470) and NCCLS proposed guideline (C28-P, 1992): a strategy for partitioning reference individuals with validation based on multivariate analysis.

In our recent project of establishing reference intervals for 13 plasma proteins following the NCCLS proposed guideline (C28-P, 1992), confounding and interacting relationships were found among criteria for partitioning reference individuals. Therefore, we found it necessary to test for the validity of the criterion by multivariate analysis so that such relationships could be revealed. Meanwhile, to find difference appropriate for the partition, sex- and age-related differences were examined in common screening tests whose reference intervals (RI) were conventionally set for each subgroup. The result led to our standard for partitioning when the difference between subgroups exceed 10% of the span of a RI derived without partitioning. Among the 13 plasma proteins, the multivariate analyses and the standard indicated gender-based RI was for IgM, alpha 1 acid glycoprotein, alpha 2 macroglobulin, and transferrin, transthyretin. None of the age-related differences were large enough. In serum IgM, ceruloplasmin, and transferrin, however, females tended to have larger differences between ages, exemplifying interaction of gender on age-related changes of the analytes. Smoking-related differences were > 10% in IgG and transthyretin. However, differences in the latter proved to be spurious multivariately. These results suggest a necessity for additional descriptions on the validity of the partitioning criterion in the NCCLS proposed guideline.

Adult↗
PubMed1997

[Simplification of on-line connection of analyzers and standardization problems].

On-line connection of automated analyzers to laboratory information system (LIS) reduces mistakes in inputing data for each samples. It also makes reporting faster in clinical laboratory. Moreover, connection of these instruments with sample transporting system enables analyses without touching samples directly. It, however, costs extremely high to construct such a system. It is because every automated analyzer uses different connecting protocol, so that we have to make a different program for each machine. For solving this problem, we have to make a standard for connecting protocol. It is very difficult to make a standard protocol fitting on all of the analyzers, considering its cost and other things. Furthermore, it must take a few decades to spreading the standard through the end users. ICCLS and NCCLS has been taking a central role for this problem since 1996, with a five-year plan to make an international standard. Until the standard will be laid, each clinical laboratories have to pay high costs to construct their systems, connecting different manufacturers' analyzers each other. Thus, we have developed a novel system which enables us to construct a laboratory automation system in a shorter time. For realizing this new system, we have reduced the number of connecting protocols for analyzers. Moreover, we have corrected the flow of laboratory works in order. Each programs are put together into a system as parts, or modules. This software system is now in operation in the clinical laboratory of Kochi Medical School. In this report, we describe the construction of this novel software system, and the effect obtained by using this system. Furthermore, we would show problems and things to be improved for making international standards for communication protocols between host and analyzing instruments.

Automation↗
PubMed1997

Improvement of impaired glucose tolerance by oral administration of vanadyl sulfate by gavage in streptozotocin-induced diabetic rats.

We examined the effect of oral administration of vanadyl sulfate by gavage on the levels of blood glucose and plasma insulin during oral glucose tolerance test (OGTT) in diabetic rats. Diabetes was induced by intravenous injection of streptozotocin at the dose of 32 mg/kg. Nondiabetic control animals were injected with an equal volume of saline. Vanadyl sulfate at a dose of 25, 50, or 75 mg/kg was given orally by gavage for 2 weeks, starting 12 hours after streptozotocin injection. When vanadyl sulfate was given twice a day, half of the one-day-dosage was given in the morning and the remaining half in the evening. Glucose tolerance test with 5 g/kg of glucose was carried out 2 weeks after administration of vanadyl sulfate. The fasting the blood glucose level in the diabetic rats was higher than that in the non-diabetic rats, whereas the plasma insulin level in the diabetic rats was lower. An increase in blood glucose seen in the glucose tolerance test was significantly greater in the diabetic rats than in the non-diabetic rats. The level of plasma insulin was increased by glucose tolerance test in the non-diabetic rats, while it was not changed in diabetic rats. Oral administration of vanadyl sulfate by gavage significantly improved the impaired glucose tolerance in the the diabetic rats in a dose-dependent manner without any change in plasma insulin level. In conclusion, oral administration of vanadyl sulfate by gavage is effective on impaired glucose tolerance in streptozotocin-induced diabetic rats.

Animals↗
PubMed1996

Direct involvement of hydrogen peroxide in bacterial alpha-hydroxylation of fatty acid.

We have reported that fatty-acid alpha-hydroxylase partially purified from Sphingomonas paucimobilis required NADH and molecular oxygen. In this study, we found that the reaction was greatly inhibited by catalase. Glutathione and glutathione peroxidase also inhibited alpha-hydroxylation, but superoxide dismutase and mannitol did not. Replacement of NADH and molecular oxygen by hydrogen peroxide increased the alpha-hydroxylation activity. In the presence of hydrogen peroxide, molecular oxygen was not required for the activity. These findings suggest that hydrogen peroxide was essential for bacterial alpha-hydroxylase.

Catalase↗
PubMed1996

Determination of reference intervals for 13 plasma proteins based on IFCC international reference preparation (CRM470) and NCCLS proposed guideline (C28-P,1992): trial to select reference individuals by results of screening tests and application of maximal likelihood method.

By using a new international reference preparation for the plasma proteins (CRM470) prepared by IFCC, we launched a project to determine reference intervals for 13 plasma proteins (immunoglobulins, compliment components, transferrin, alpha 1antitrypsin, alpha 1acid glycoprotein, haptoglobin, alpha 2macroglobulin, ceruloplasmin, albumin, transthyretin) in accordance with the guideline proposed by NCCLS. As reference individuals, 999 subjects were first selected through medical examination and a health-check questionnaire. However, there were many who had "abnormal" values in some of the 25 screening tests results measured simultaneously (serum enzymes, lipids, blood counts, etc.). Therefore, we adopted a criterion that those individuals who had "abnormal" values (beyond 99% confidence intervals) in the 25 tests would be excluded. The exclusion resulted in appreciable narrowing of the distributions in all 13 plasma proteins. This implied that "apparent" normality of major screening tests results may be used as a criterion to select truly relevant reference individuals. A parametric approach using a modified Box-Cox power transformation formula and the maximal likelihood estimation led to almost perfect normalization of the reference distributions on all the items tested. Since the nonparametric method proposed by the NCCLS guideline gave less reproducible results in our simulation study, the parametric method appears to be a method of choice for the calculation.

Blood Chemical Analysis↗
PubMed1996

An improved method for rapid analysis of the fatty acids of glycerolipids.

An improved rapid procedure to determine the fatty acid composition of glycerolipids is described. The procedure includes KOH-catalyzed transesterification and high-speed gas chromatography. Glycerolipids (20-40 mg) were mixed with 2 mL of hexane and 0.2 mL of 2 M methanolic KOH at room temperature for 1-2 min. The fatty acid methyl esters in the hexane layer were analyzed by gas chromatography on 10% SP-2340 at 240 degrees C. Methyl linolenate and docosahexaenoate eluted within 2 and 5 min, respectively. Analysis was thus completed within 5 min for common vegetable oils and 8 min for fish oils.

Cholesterol Esters↗
PubMed1996

Effects of thoracic epidural anesthesia on changes in ischemic myocardial metabolism induced by intracoronary injection of endothelin in dogs.

OBJECTIVE: Thoracic epidural anesthesia (TEA) has been reported to alleviate ischemic damage to the myocardium. Endothelin, an endothelium-derived peptide and a potent coronary vasoconstrictor, may contribute to poor cardiac perfusion and ischemia. The objective was to examine regional myocardial metabolism during ischemia caused by intracoronary injection of endothelin with and without TEA. DESIGN: The three experimental groups and three treatments were randomized. SETTING: All studies were conducted in a university research laboratory. PARTICIPANTS: Thirty anesthetized dogs comprised the study groups. INTERVENTIONS: Study animals were divided into three groups of 10 animals each identified as normal saline (NS); TEA; and TEA + blood pressure controlled (TEA + BPC). The NS group had 0.5 mL/kg of normal saline injected into the T4-5 epidural space. The TEA group had 0.5 mL/kg of saline containing 1% lidocaine injected into the T4-5 space. The TEA + BPC group had blood pressure and heart rate maintained at pre-epidural injection values by partially occluding the descending aorta and by atrial pacing. Endothelin (15 pmol/kg) was bolus injected into the left anterior descending (LAD) artery of each heart. Systolic and diastolic blood pressure, heart rate, and LAD coronary blood flow (CBF) were monitored. Three minutes after injection of endothelin, myocardial tissue was sampled from the distribution of the LAD artery and from the control, left circumflex (LCx) artery. ATP, ADP, AMP, lactate, and pyruvate were measured by enzymatic methods. MEASUREMENTS AND MAIN RESULTS: It was found that in each group endothelin consistently decreased LAD CBF, but the decrease was less in the TEA + BPC group. In the tissue distribution of the LAD, the levels of ATP and energy charge potential were lower, and the level of lactate was higher in the NS group than in the TEA or the TEA + BPC groups (p < 0.01). CONCLUSIONS: These results confirm that (1) endothelin injected into the LAD artery decreases CBF and causes selective myocardial ischemia in a fashion similar to intravascular stenosis of the LAD rather than to mechanical occlusion and (2) TEA, with or without pressure support, lessens the degree of regional ischemia induced by injection of endothelin in the LAD.

Adenosine Triphosphate↗
PubMed1996

Effects of adenine nucleotide analogues on myocardial dysfunction during reperfusion after ischemia in dogs.

We examined effects of adenine nucleotide on ischemic myocardial stunning in dogs. Pentobarbitalanesthetized open-chest dogs were subjected to 20-min ligation of the left anterior descending coronary artery (LAD), followed by reperfusion for 30 min. Either saline, 5 mM 8-bromo-5'-AMP (tributyryl-AMP), or 30 mM N6, 2', 3'-tributyryl-5'-AMP (tributyryl-AMP), 5 mM 5-amino-4-imidazole carboxamide riboside (AICAr) as a positive reference, was infused at 0.1 ml/kg/min in the left femoral vein throughout the experiment. The myocardial contractile function was measured by ultrasonometry. The tissue levels of high-energy phosphates in the reperfused heart were determined. Myocardial contractile function assessed by % segment shortening (%SS) in the saline-infused group decreased during ischemia and returned toward the preischemic level during reperfusion but incompletely. A significant improvement in the %SS during reperfusion was observed in the 8-bromo-AMP- and AICAr-infused groups but not in the tributyryl-AMP-infused group. The magnitude of the protective effect of the drugs on myocardial contractility during reperfusion was 8-bromo-AMP > AICAr > tributyryl-AMP = saline. Only in the 8-bromo-AMP-infused group were the levels of ATP, ADP, and total adenine nucleotides in the reperfused heart significantly higher than those in the saline-infused group. The present result indicates that 8-bromo-AMP improves the ability of the heart to recover from ischemia and reperfusion associated with a significant restoration of ATP.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1996

Effects of BIBR-277, an angiotensin II type 1 receptor antagonist, on stunned myocardium in dogs.

BACKGROUND: Angiotensin converting enzyme inhibitors can protect the myocardium from ischaemic damage. We examined the effect of BIBR-277, an angiotensin II receptor type 1 antagonist, on myocardial stunning in dogs. METHODS: Pentobarbital-anaesthetized open-chest dogs were subjected to 20 min ligation of the left anterior descending coronary artery, followed by reperfusion for 60 min. Saline or 0.3, 1 or 3 mg/kg body weight BIBR-277 was injected intravenously 10 min before coronary ligation. The myocardial contractile function was measured by ultrasonometry. The tissue levels of energy metabolites in the 60 min reperfused heart were determined. RESULTS: Myocardial contractile function assessed in terms of percentage segment-shortening in the saline-treated group decreased during ischaemia and returned towards the pre-ischaemic level during reperfusion but incompletely (myocardial stunning). A significant and dose-dependent improvement in the percentage segment-shortening during reperfusion was observed in the BIBR-277-treated groups. The levels of ATP, ADP and AMP in the reperfused heart were not modified by BIBR-277 treatment compared with those in the saline-treated group. CONCLUSION: BIBR-277 ameliorates the myocardial contractile dysfunction during reperfusion after ischaemia, although it did not bring about any improvement in the high-energy phosphate levels in the reperfused heart.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1996

Diagnosis of lymphoma in paraffin wax sections by nested PCR and immunohistochemistry.

AIMS: To investigate whether nested polymerase chain reaction (PCR) and immunohistochemistry can be used to diagnose malignant lymphoma. METHODS: Paraffin wax embedded tissue sections from 31 patients with malignant lymphoma were analysed by nested PCR and immunohistochemistry using standard protocols. RESULTS: Nested PCR amplification of 1 pg DNA confirmed monoclonality in B cell lymphoma; PCR amplification of 10 pg DNA confirmed monoclonality in T cell lymphoma. Twenty seven (87%) samples were diagnosed as malignant lymphoma by nested PCR, and 24 (77%) by immunohistochemistry. Seven samples were diagnosed as malignant lymphoma by nested PCR, but not by immunohistochemistry, whereas the use of both procedures gave a diagnosis of malignant lymphoma in all 31 samples. CONCLUSIONS: A combination of immunohistochemistry and nested PCR can be used to diagnose malignant lymphoma in routine paraffin wax embedded sections.

Adult↗
PubMed1996

Efonidipine, a long-acting dihydropyridine derivative, attenuates coronary vasoconstriction induced by endothelin-1 in dogs.

Effect of efonidipine, a long-acting dihydropyridine derivative, on the endothelin-1 (ET-1)-induced coronary vasoconstriction was studied in open-chest anesthetized dogs. Efonidipine (0.03 or 0.1 mg/kg) was administered i.v. 10 min before an intracoronary injection of ET-1 (30 pmol/kg). An intracoronary injection of ET-1 decreased coronary blood flow (CBF) that was measured by a flow probe. The ET-1-induced decrease in CBF was sustained for more than 30 min without significant changes in blood pressure and heart rate. Pretreatment with efonidipine attenuated the decrease in CBF induced by ET-1 significantly and dose-dependently. ET-1 also reduced coronary diameter for more than 30 min as evaluated by the coronary angiography technique. Pretreatment with efonidipine also attenuated the reduction in coronary diameter induced by ET-1 significantly and dose-dependently. These effects of efonidipine were sustained for at least 30 min after the ET-1 administration. It is concluded that efonidipine attenuates the ET-1-induced vasoconstriction, and therefore the drug would be useful for some patients with variant angina, in which ET-1 is involved in the genesis of coronary vasoconstriction.

Animals↗
PubMed1996

K-7259, a novel dilazep derivative, and d-propranolol attenuate H2O2-induced cell damage.

We studied the effects of dilazep, K-7259 (a novel derivative of dilazep) and d-propranolol on the change in cell shape and accumulation of nonesterified fatty acids (NEFA) induced by hydrogen peroxide (H2O2) in isolated rat cardiac myocytes. Myocytes were incubated in a Krebs-Ringer bicarbonate buffer containing 2 mM diethyltriamine pentaacetic acid (DETAPAC) and 2mM FeSO4 for 10 min, and then treated with 2mM H2O2 for 50 min. Before the treatment with H2O2, the percentage of the number of rod-shaped cells to that of total cells was 66 +/- 2%, and decreased to 35 +/- 3%, 25 +/- 4% and 14 +/- 2%, after 30, 40 and 50 min of the H2O2 treatment, respectively. The levels of NEFA (lauric, myristic, palmitoleic, arachidonic, linoleic, palmitic, oleic and stearic acids) increased after the treatment with H2O2. In the absence of FeSO4 and DETAPAC, however, H2O2 did not have these effects, and therefore all the experiments with drugs were performed in the presence of Fe2SO4 and DETAPAC. K-7259 (30 microM) and d-propranolol (50 microM) attenuated both the changes in cell shape and accumulation of NEFA induced by H2O2, whereas dilazep (30 or 50 microM) did not. N-(2-mercaptopropionyl)glycine (2 mM), an .OH scavenger, inhibited the H2O2-induced changes completely. These results suggest that K-7259 and d-propranolol attenuate the H2O2-induced changes in cell shape and accumulation of NEFA, probably because of their .OH-scavenging effect.

Animals↗
PubMed1996

[Establishment of reference intervals and physiological parameters for 13 serum proteins in healthy Japanese adults].

Using a nephelometry with a new calibrator in which values were assigned from EU/CRM470, a new international reference preparation, we have established for the first time the reference intervals of 13 different serum proteins in Japanese adults. Based on the NCCLS guideline C28-P, a new statistical and concrete procedure was revised and used for this study. It is clearly shown here that standardisation of serum proteins can be possible under the qualified assay system, making it possible to share the reference intervals among laboratories under well-controlled quality assurance. New aspects of serum protein variations were discovered in relation to physiologic changes and life styles.

Adult↗
PubMed1996

[Intra-individual and seasonal variations of thyroid function tests in healthy subjects].

We report intra-individual and seasonal variations of thyroid function tests in healthy subjects. Blood samples were obtained from thirteen healthy males and seven healthy females every two weeks over a period of one year, and totally 25 samplings of each were made. Serum thyrotropin (TSH), free thyroxine (FT4) and free triiodothyronine (FT3) were measured after the completion of the sampling. The 25 samples from each subject were always assayed with the same assay run. Variations of FT4 and FT3 in each subject were narrow and approximately one-third of normal reference ranges. The magnitude of individual variation of TSH values was proportional to the average of TSH in each individual. Serum TSH and FT3 values during winter were significantly higher than those during summer, but such change was not observed on serum FT4.

Adult↗
PubMed1996

[Derivation of latent reference intervals from routine laboratory database: its principle, validity and methodological implications for laboratory informatics].

A new method to derive reference from routine laboratory database intervals was developed. It depends on (1) availability of multiple screening tests results, (2) initial estimates for the reference intervals (RI) and (3) exclusion of data with multiple abnormalities in "related" test items. We designated those data which remained after exclusion as "latent reference values". RI was calculated from them parametrically employing a modified Box-Cox power transformation and maximal likelihood method. After RI were derived for all the items, they were used as a new set of RI estimates and the series of exclusion/calculation procedures were repeated for 7 times. The validity of the latent reference intervals (LRI) derived from routine biochemical screening test results were evaluated in three ways, by comparing them (1) with RIs determined conventionally from healthy individuals, and (2) with LRIs derived from qusi-normal individuals (blood donors), and (3) with LRIs obtained from a simulated healthy population which was generated as multivariate normal random values.

Adult↗