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Biomedical subjects

Y Ichihara

Publications and source records attributed to Y Ichihara.

At least 19 recordsLinked to original sources
PubMed1996

Newly developed ST-T abnormalities on the electrocardiogram and chronologic changes in cardiovascular risk factors.

An ST-T abnormality on an electrocardiogram (ECG) is known to independently predict subsequent morbidity and mortality from cardiovascular diseases. But how ST-T abnormality develops in relation to chronologic changes in cardiovascular risk factors has not been fully discussed. Sixty-eight men whose ECG had been initially normal but who exhibited ST-T abnormality later (ST-T subjects) were identified among 21,579 apparently healthy adults who had undergone comprehensive health examinations for > 10 years. Echocardiography proved that 26 of 29 examinees among ST-T subjects had left ventricular hypertrophy. Antihypertensive drugs were given to 26 of the ST-T subjects. Their cardiovascular risk factors were chronologically reviewed from 10 years before the onset of definite ST-T abnormality, and were compared with those of 68 men whose ECG had remained consistently normal for 10 years (controls). Mean values of systolic and diastolic blood pressure gradually increased over 10 years (from 127/78 to 144/84 mm Hg) among ST-T subjects, but showed little change (from 122/76 to 124/77 mm Hg) during the same period in controls. The time course of blood pressure over 10 years was similar in ST-T subjects, irrespective of final blood pressure level. Mean serum cholesterol and glucose increased over 10 years in both ST-T and control subjects. Uric acid decreased over 10 years (from 6.1 to 5.6 mg/dl) only in ST-T subjects. Multivariate analysis revealed that blood pressure and uric acid before onset of ST-T abnormality were chronologically changed independent of other risk factors. The time course of risk factors may be of great importance in the development of cardiovascular disorders.

Blood Pressure↗
PubMed1996

Body surface distribution of significant changes in QRST time-integral values after radiofrequency catheter ablation in patients with Wolff-Parkinson-White syndrome.

We analyzed 87-lead body surface QRST time-integral values (QRST values) in 29 patients with Wolff-Parkinson-White syndrome (group A, 17 patients with manifest left-sided accessory pathway; group B, 6 patients with manifest right-sided accessory pathway; and group C, 6 patients with concealed left-sided accessory pathway), before, 1 day after, and 1 week after radiofrequency catheter ablation (RCA). The number of leads with abnormal QRST values was significantly lower 1 week after RCA compared with those before RCA and 1 day after RCA in groups A and B (p < 0.05); there was no significant difference in QRST values before and 1 day after RCA in groups A and B. The QRST values over areas with preexisting repolarization abnormalities were significantly altered 1 week after RCA compared with before and 1 day after RCA in groups A and B (p < 0.01). However, there was no significant difference in the QRST values over areas without preexisting abnormalities before RCA. In group C, there were no significant differences in the QRST values or the number of leads with abnormal QRST values before, 1 day and 1 week after RCA. In conclusion, RCA did not significantly influence repolarization properties over areas without preexisting abnormalities, but gradually reduced preexisting repolarization abnormalities, which were closely related to the location of the accessory pathway in patients with manifest Wolff-Parkinson-White syndrome. Our results suggest that body surface QRST values are useful for assessment of repolarization abnormalities during the periablation period.

Adolescent↗
PubMed1995

Evaluation of QRST isointegral maps in detecting posterior myocardial infarction with and without conduction disturbance.

We investigated the usefulness of QRST isointegral maps (I-maps) for detecting posterior myocardial infarction (MI) with and without conduction disturbance. The I-maps were recorded during sinus rhythm and right ventricular (RV) pacing, which simulated left bundle-branch block (LBBB) in 19 patients with and in 20 patients without MI. Data on 608 normal subjects were used as controls. The "-2 SD area," where the QRST integral value was less than the lower limit of the normal range, was assessed by sigma DM (sum of QRST integral values below the normal range). Posterior MI was diagnosed with a sensitivity of 84%, a specificity of 90%, and a diagnostic accuracy of 87%, assuming that MI was present if sigma DM exceeded 50 mVms. During simulated LBBB, when the criterion sigma DM more than 250 mVms was used, the sensitivity, specificity, and diagnostic accuracy were 79, 75, and 77%, respectively. Thus, I-maps may be useful in detecting posterior MI in patients with and without an intraventricular conduction disturbance.

Adult↗
PubMed1995

Antineoplastic agents, 325. Isolation and structure of the human cancer cell growth inhibitory cyclic octapeptides phakellistatin 10 and 11 from Phakellia sp.

The two new marine sponge (Phakellia sp., western Pacific Ocean) constituents, phakellistatin 10 [1] and 11 [2], were found to be cyclic octapeptides that significantly inhibited growth of the murine P-388 lymphocytic leukemia (ED50 values of 2.1 and 0.20 micrograms/ml, respectively) and human cancer cell lines. The structures were established based on results of extensive tandem ms/ms and high-field (500-MHz) 2D 1H- and 13C-nmr analyses. All of the amino acid units (except Trp, not determined) were found to correspond to the (S)-configuration.

Amino Acid Sequence↗
PubMed1995

[Lifestyles and renal damage--association of smoking, drinking and physical activity with subsequent proteinuria].

To examine the role of lifestyles in the subsequent development of renal damage, the association of smoking, drinking and physical activity with subsequent proteinuria was investigated utilizing a longitudinal study. The subjects were 7,701 males aged 20-84 years, who participated in health examinations at Aichi Prefectural Center of Health Care, Nagoya, Japan, both in 1989-1990 and 1992-1993, and who showed no proteinuria at the first examination. Lifestyles at the first examination were compared between 140 men with, and 7,561 men without, newly developed proteinuria at the second examination. Age-adjusted odds ratios (ORs) of lifestyle factors for proteinuria were computed, and further the ORs were adjusted for age, systolic blood pressure, fasting plasma glucose level and other covariates obtained using multiple logistic regression analysis. Major significant findings which emerged from the present study were as follows. (a) The greater the consumption of alcohol per day, the higher the risk of subsequent proteinuria (trend p = 0.003). Heavy drinkers who consumed more than 58 g of alcohol per day experienced an increased risk (OR relative to non-drinker: 2.52). (b) Those who exercised less than once a week, and those who avoided walking even a short distance were at an increased risk (OR: 1.46, 1.55, respectively). Heavy drinking and low physical activity were found to be significantly associated with an increased risk of subsequent proteinuria even after adjusting for the covariates. An increasing risk of subsequent proteinuria with number of cigarette smoked per day was observed by univariate and multivariate analysis but without statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Isopotential map].

Isopotential map, constructed from ECGs of many body surface electrodes, is an expression of body surface distribution of cardiac potentials at a moment. This ECG mapping technique, providing far more information than the conventional 12-lead ECG recordings, has proved moving multiple dipoles of the heart as electric power generator, and has clarified break through minimum indicative of the right ventricular epicardial depolarization. It is also utilized for diagnosis of right ventricular or posterior myocardial infarction, left ventricular hypertrophy, localization of accessory pathway in WPW syndrome, indication for intervention in acute myocardial infarction, identification of responsible coronary artery in angina pectoris, risk of ventricular tachycardia etc. Further information on the heart will be expected through this mapping technique.

Body Surface Potential Mapping↗
PubMed1995

Spatial ventricular gradient in patients with Wolff-Parkinson-White syndrome in comparison with normal subjects: vectorcardiographic evidence for significant repolarization changes due to preexcitation.

We investigated the use of the spatial ventricular gradient (VG) from vectorcardiogram (VCG) to determine whether significant repolarization differences were present in patients with WPW syndrome compared with normal subjects and also examined which VG parameter (i.e., elevation, azimuth, and magnitude) reflected the differences in repolarization properties during preexcitation. VG was calculated in 49 patients of Wolff-Parkinson-White (WPW) syndrome (group A: left-sided accessory pathway, n = 29; group B: right-sided, n = 20). Group N consisted of 607 normal subjects. In group A, the azimuth of VG was significantly (p < 0.01) greater than in groups B and N. In group B, the elevation of VG was significantly (p < 0.01) greater than in groups A and N. There were no significant differences in the magnitude of VG among groups. QRS duration was significantly (p < 0.01) related with the elevation of VG in group B. These findings suggested that VG is useful for spatial evaluation of repolarization abnormalities during preexcitation, which are related to the site of the accessory pathway.

Adolescent↗
PubMed1994

Evidence for defects in V(D)J rearrangements in patients with severe combined immunodeficiency.

We investigated the patterns of DNA rearrangements at loci for Ig JH genes in patients with severe combined immunodeficiency (SCID). Four SCID patients without B cells (B- SCID) and four SCID patients with B cells (B+ SCID) were examined. Bone marrow cells of these patients were transformed with EBV. The majority of the transformed cells from three B- SCID patients had the germline configuration at their JH gene loci. The rearranged fragments from one patient were analyzed extensively. The rearranged regions in all of the fragments had a common structure wherein two fragments derived from the JH-S mu region were connected inversely. The possible presence of rearranged forms of VHDJH and DHQ52JH sequences in bone marrow cells of two B- SCID patients were examined directly by the polymerase chain reaction (PCR) method. In one patient, we found neither a VHDJH sequence nor a DHQ52JH sequence within the range of sensitivity of the PCR method. In another patient, we found a VHDJH sequence at an extremely low level and DHQ52JH sequences at a relatively low level. Either RAG-1 or RAG-2 gene was not expressed in the B- SCID-derived cell lines. B+ SCID patients did not show any abnormalities in terms of VHDJH rearrangements. These results indicate that B- SCID may be caused by defects in factors involved in V(D)J rearrangements.

Base Sequence↗
PubMed1994

[Significance of phrenic nerve block in the anesthetic management of laparoscopic cholecystectomy].

The significance of phrenic nerve block was studied in the anesthetic management of laparoscopic cholecystectomy. Right phrenic nerve block with 1% mepivacaine 10 ml was performed after the patients were epidurally catheterized and anesthetized with isoflurane and nitrous oxide in oxygen. Intraoperative anesthetic requirement and postoperative shoulder pain incidence in patients with this block were compared with those in patients without block. Addition of the phrenic nerve block to general and epidural anesthesia did not reduce the intraoperative dosage of isoflurane, but it significantly prevented occurrence of postoperative right shoulder pain. It is known that phrenic nerve contains sensory element and that laparoscopic procedures of gall bladder elicit noxious stimuli which cannot be blocked by ordinary epidural anesthesia for abdominal surgery. Also, shoulder pain is said to be phrenic nerve-mediated referred pain. Our study suggests that blockade of these stimuli is effective in preventing postoperative event rather than intraoperative.

Adult↗
PubMed1993

Construction of new T vectors for direct cloning of PCR products.

More than half of the products of PCR contain an extra A residue at the 3' end, which is the result of the template-independent activity of Taq polymerase. To facilitate cloning of the products of PCR without modification, T vectors, which have a single overhanging T residue at the 3' end, have been developed. In the present study, we constructed new T vectors which can be prepared in the laboratory by simple digestion with the restriction enzymes AspEI or Eam1 105I.

Amino Acid Sequence↗
PubMed1993

The gene loci for immunoglobulin heavy chains in precursor B cell lines from a patient with severe combined immunodeficiency appear able to participate in DNA rearrangement but have a germ-line configuration.

In a previous study (Immunogenetics 1988. 27:330) with Epstein-Barr virus, we established lines of precursor B cells from bone marrow cells of a patient with severe combined immunodeficiency in whom the numbers of B cells and T cells were markedly reduced. Although based on their surface markers these cell lines appeared to be at an early stage of B cell differentiation, the gene loci for immunoglobulin heavy chains (IgH) retained the germ-line configuration on both chromosomes in almost all the transformants. In this study, we found that the enhancer sequence, located between the JH and mu genes, was hypomethylated and an abundance of the germ-line Cmu transcript was detected in these cell lines by Northern hybridization. These results suggest that the chromatin structure of the IgH gene locus in these cell lines is accessible to VDJ recombinase and is able to participate fully in DNA rearrangement. By contrast, we did not detect transcripts of the RAG-1 and RAG-2 genes, which are required for V(D)J recombination at gene loci for immunoglobulin and T cell receptors. Thus, it seems likely that these cell lines fail to initiate the V(D)J recombination process because of some deficiency in the formation of VDJ recombinase, which includes the inability to express RAG genes.

B-Lymphocytes↗
PubMed1993

Estimation of anterior infarct size with body surface QRST integral maps in the presence of abnormal ventricular activation sequence in dogs.

The possibility of estimating infarct size with body surface QRST integral (IQRST) maps was investigated in dogs. IQRST maps were constructed from 87-lead body surface ECGs, which were recorded 1 week after the production of anterior myocardial infarction during artificial pacing that simulated normal conduction, left bundle branch block, and Wolff-Parkinson-White syndrome in 11 dogs. Small differences were observed between the IQRST maps of the normal conduction and left bundle branch block models (r = 0.93, root mean square difference = 8.71 mVmsec) and between the normal conduction and Wolff-Parkinson-White models (r = 0.96, root mean square difference = 6.03 mVmsec). Summation of the QRST integral values over the body surface leads (QRST index) inversely correlated with infarct size in all three conductions models: r = 0.91 (p < 0.001) in the normal conduction model; r = -0.81 (p < 0.001) in the left bundle branch block model; and r = -0.86 (p < 0.001) in the Wolff-Parkinson-White model. These results show that IQRST maps permit noninvasive estimation of infarct size, even in the presence of abnormal activation sequences.

Animals↗
PubMed1993

Correlation between various parameters derived from body surface maps and ejection fraction in patients with anterior myocardial infarction.

To determine the best map parameter to predict cardiac function, various map parameters were correlated with the left ventricular ejection fraction (EF) in patients with a previous (between 3 months and 1 year) anterior myocardial infarction, but without overt congestive heart failure or ventricular dyssynergy. From 300 consecutive patients with a previous myocardial infarction, 82 patients with only an anterior infarction and who underwent cardiac catheterization and body surface mapping were selected for this study. The maps from 100 healthy subjects were used as normal controls. Body surface maps using 87 unipolar electrodes were recorded and various parameters were derived from the Q map, the QRS departure maps, the QRS isointegral (IQRS) map, and the QRST isointegral (IQRST) maps. They were compared with the angiographically determined EF. The EF was correlated with nQ (r = -0.72), four parameters derived from the QRS departure map (r ranged from -0.73 to -0.79), two parameters derived from the IQRS map (r = -0.90 and -0.86), and two parameters derived from the IQRST map (r = -0.84 and -0.85). Some parameters derived from body surface maps were found to have a very high correlation with the EF in patients who had a previous anterior myocardial infarction.

Electrocardiography↗
PubMed1993

Comparison of nucleotide sequences from upstream of the DQ52 gene to the S mu region of immunoglobulin heavy-chain gene loci between Suncus murinus, mouse and human.

The nucleotide sequence of a 4621 base pair fragment of DNA, from a position upstream of DSQ52 to the S mu region within immunoglobulin heavy-chain gene loci of Suncus murinus was determined. The sequence contained one D gene, three JH genes and an enhancer. Suncus murinus is an insectivore and is one of the most primitive mammals. Both primates and rodents are thought to have originated from insectivores and to have evolved separately. We also determined the nucleotide sequence of a region between human JH genes and the enhancer which has not previously been reported. Thus, the sequences of the entire region from each of the three species, Suncus murinus, human and mouse are now available. Comparison of the nucleotide sequence of this region between these three species indicated that D and JH genes, consisting of coding and signal regions, are highly conserved. Moreover, although extensive sequence homology in the region between JH and S mu was observed between mouse and human, only core portions of the enhancer region of Suncus murinus exhibited homology to those of mouse and human. Sequence conservation of JH genes in Suncus murinus, mouse and human was observed not only at the amino-acid level, but also at the nucleotide level, including the third letters of the codons. It is suggested that JH genes may play a role in the metabolism of the DNA and/or RNA.

Algorithms↗
PubMed1993

The ability of QRST isointegral maps to detect myocardial infarction in the presence of simulated left bundle branch block.

The clinical value of QRST isointegral maps (I-maps) for the detection of myocardial infarction (MI) in the presence of left bundle branch block (LBBB) was investigated. We recorded I-maps during sinus rhythm and right ventricular (RV) pacing, which simulated LBBB, in 62 patients with MI (42 patients had at least one akinetic segment and the remaining 20 patients had only hypokinesis or normal contraction) and 26 patients without MI. An abnormal decrease in the QRST value of the I-map was assessed by the difference map (D-map), which indicated a '-2SD area', where the QRST integral value was less than the lower limit of the normal range (mean -2SD) calculated from 608 normal individuals. The I-maps recorded during the two activation sequences were similar to each other in patients with and without MI (r = 0.87 and 0.92, respectively). The '-2SD area' was located over the left anterior chest in patients with an anterior MI and over the lower torso in patients with an inferior MI during each activation sequence. We were able to diagnose MI during simulated LBBB with a sensitivity of 84%, a specificity of 81% and a diagnostic accuracy of 83% when we used the criterion that MI is present if the sum of QRST integral values below the normal range (sigma DM) exceeds 100 mV.ms. We were able to diagnose an akinesis with a sensitivity of 81%, a specificity of 85% and a diagnostic accuracy of 83% when we used the criterion that akinesis is present if sigma DM exceeds 500 mV.ms during simulated LBBB.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Effects of right ventricular pacing on QRST isointegral maps in patients with and without myocardial infarction: body surface distribution of significant changes in QRST area compared to supraventricular complex.

To assess the effects of right ventricular (RV) pacing on body surface QRST distributions, we recorded QRST isointegral maps (I-maps) during sinus rhythm and RV pacing in 25 patients with anterior myocardial infarction (MI), 19 with inferior MI, and 14 without MI. The QRST values at each lead point recorded during sinus rhythm and RV pacing with an 87-lead system were analyzed with a paired t-test in each patient. An abnormal decrease in the QRST value of the I-map was assessed by the difference map, which indicated a "-2SD area," where the QRST integral value was less than the normal range (mean - 2SD) calculated from 608 normal individuals. The I-maps were similar during the two activation sequences in patients with and without MI. However, during RV pacing, QRST values significantly decreased over the upper right anterior chest and increased over the lower left anterior chest and back. The sigma DMs (sum of QRST integral values below the normal range) for both activation sequences were strongly correlated in patients with anterior MI and with inferior MI (r = 0.91 and r = 0.92, respectively; P < 0.001). Although small but significant changes in QRST values were detected, the distribution of the "-2SD area" and the sigma DM were similar during both activation sequences in patients with prior MI. Thus, these findings demonstrate that an altered activation sequence produces small but significant changes in QRST values but that I-maps still provide information that is useful for the diagnosis of MI during RV pacing.

Adult↗
PubMed1992

Effects of simulated left bundle branch block on QRST time-integral values of 12-lead electrocardiograms in patients with and without prior anterior wall myocardial infarction.

The effects of right ventricular pacing, which simulated left bundle branch block (BBB), on QRST time-integral values of 12-lead electrocardiograms (ECGs) were examined, and the clinical usefulness of QRST values for estimating the severity of left ventricular wall motion abnormalities due to a prior anterior wall myocardial infarction (MI) in the setting of left BBB were evaluated. Digitized ECGs were recorded during normal sinus rhythm and simulated left BBB in 38 patients (24 with and 14 without prior anterior wall MI). QRST values were calculated in each lead point of 12-lead ECGs. Data from 608 normal subjects were used as control values; the mean +/- 2 SD of these values was regarded as the normal range. The parameter sigma DE was defined as the sum of the differences between the normal mean QRST value and the QRST values of a given patient in leads where the QRST value was less than the normal range. The correlation coefficient of sigma DE for the 2 activation sequences was highly significant. Although small but significant changes were seen in QRST values in leads I, II, III, aVR, aVF and V1 during simulated left BBB, left precordial leads showed no significant changes in QRST values. A criterion of sigma DE > 40 mV.ms for detecting an anterior wall MI showed a sensitivity of 88%, a specificity of 93%, and a diagnostic accuracy of 89%. The sigma DE was significantly (p < 0.001) correlated with the asynergy index calculated from left ventriculograms.(ABSTRACT TRUNCATED AT 250 WORDS)

Bundle-Branch Block↗