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Biomedical subjects

T Nagaya

Publications and source records attributed to T Nagaya.

At least 91 records · Page 5Linked to original sources
PubMed1989

Sister chromatid exchange analysis in lymphocytes of workers exposed to hexavalent chromium.

To investigate the usefulness of sister chromatid exchange (SCE) analysis in lymphocytes as an indicator for mutagenic effects after in vivo exposure to hexavalent chromium (Cr), SCE frequency was analysed in lymphocytes of 44 Cr platers occupationally exposed to hexavalent Cr and 47 controls. Although urinary Cr analysis confirmed that the Cr platers were exposed to Cr, no effects of the exposure on SCE frequency were found. Smokers, both Cr platers and controls, had a significantly higher SCE frequency than non-smokers. These results suggest that SCE analysis in human lymphocytes is not a good indicator of possible mutagenic effects of exposure to hexavalent Cr.

Adult↗
PubMed1989

Vectorcardiographic criteria for diagnosis of high lateral infarction--supplement for Chou's criteria.

The concept of high lateral myocardial infarction (HLMI) has not been clearly defined, so criteria for its vectorcardiographic (VCG) diagnosis have had no firm basis. However, we have reported that HLMI, expressed as abnormal Q waves in lead aVL on the electrocardiogram, corresponds to necrosis of the area usually supplied by the diagonal branches of the left anterior descending coronary artery. Here, we evaluated conventional VCG criteria for the diagnosis of HLMI on the basis of angiographic findings, and selected the criteria of Chou as typical. The frontal plane VCG was analyzed in 46 patients with HLMI on angiograms; other subjects were 233 healthy controls and 194 patients with left ventricular hypertrophy. Chou's criteria had good specificity, but sensitivity was unsatisfactory (32/46, or 70%). Accordingly, we examined various parameters of the QRS and T loops and found that the addition of four new criteria to Chou's improved sensitivity (46/46, or 100%) without impairment of specificity. The additional criteria are; 1) initial counterclockwise rotation of the QRS loop, 2) the ratio of the maximal QRS magnitude to the maximal T magnitude less than 4.5, 3) direction of the maximal T between +60 degrees and +180 degrees, 4) the QRS-T angle between 40 degrees and 135 degrees, all in the frontal plane.

Adult↗
PubMed1988

Microdeletion associated with the integration process of hepatitis B virus DNA.

Hepatitis B virus (HBV) DNA is often found in integrated form in hepatocellular carcinomas (HCC) and in non-cancerous liver cells of chronic carriers of HBV. However, the process of integration has not been well understood. Analyses of integrant DNA was expected to give clues. However, the majority of the integrants are products of multistep rearrangements following integrations, and analysis of randomly selected samples do not give clues for understanding the process of primary integrant formation. Therefore, one must select an appropriate integrant(s) that has a simple structure. We surveyed a collection of integrants prepared from many HCC's, and found one integrant that has the simplest structure so far studied: The viral genome is almost complete, is joined to cellular DNA using the cohesive end of the viral DNA, and furthermore, the "left" and "right" flanking cellular DNA's are almost contiguous. Analysis of the unoccupied sites in cellular DNA showed that, although almost contiguous, it has generated a microdeletion (15 base pairs) in the target sequence. This target sequence has a short region of homology to the sequence in the viral genome located close to the junction. One integrant with strikingly similar features has been reported independently. Two similar, but not identical cases from literatures could be added to this category. Therefore, the integrants with these properties may represent a unique category among those prepared from hepatocellular carcinomas. Based on these findings, we propose that this integrant represents the primary product of integration, and discuss the intermediate acting in the process of integration.

Base Sequence↗
PubMed1988

Relationship between abnormal Q waves in lead aVL and angiographic findings--a study to redefine "high lateral" infarction.

To re-evaluate the concept of "high lateral" myocardial infarction, angiographic findings were analysed in 29 patients with remote infarction and abnormal Q waves in lead I or aVL but no abnormal Q waves in other leads and no prominent R wave in lead V1. All patients except one showed asynergy in the anterior segment on right anterior oblique left ventriculogram. Asynergies in other segments were, if present, mild or small. Critical narrowing was present in the diagonal branches or in their "parent" arteries (that is, the left anterior descending artery or left main trunk) in 28 patients but in the circumflex artery in only 3 patients. Thus, the traditional concept that a "high lateral" infarction is myocardial necrosis of the basal aspect of the left ventricle, receiving its blood supply from the circumflex artery, needs correction. "High lateral infarction" corresponds to necrosis of the area between the obtuse margin and the interventricular groove ordinarily supplied by the diagonal branches of the left anterior descending artery. Such infarctions are expressed by asynergy of the anterior segment rather than the posterior segment.

Coronary Angiography↗
PubMed1988

Efficacy and tolerance of tiaprofenic acid during long term administration to rheumatoid arthritis patients.

In a multicentre trial, tiaprofenic acid was administered in a dosage of 600 mg/day for 12 months to 109 patients with rheumatoid arthritis. The results in 79 patients, who did not receive any other non-steroidal anti-inflammatory drugs concomitantly, were assessed. Of the 79 patients, 11 withdrew from the study within one year. The reasons for withdrawal were personal reasons in 4 cases, side effects or abnormal laboratory values in 2, no change or aggravation of symptoms in 2, improvement of symptoms in 2, and identification of systemic lupus erythematosus in one. Overall improvement was definite in 27 patients (34.2%) and slight in 21 patients (26.6%). Overall usefulness was definite in 30 patients (38%) and slight in 27 patients (34.2%). The duration of morning stiffness, joint index and Lansbury activity index showed significant improvement after 6 months' administration. Side effects were observed in 2 cases (2.5%) and abnormal laboratory results were seen in 3 (3.8%). These disappeared on either continuation or discontinuation of treatment.

Adult↗
PubMed1988

Detection of mRNA of prolactin and ACTH in clinically nonfunctioning pituitary adenomas.

Clinically nonfunctioning pituitary adenomas have been thought to synthesize some pituitary hormones as shown by studies involving cell culture, immunocytochemistry, or measurement of hormone levels in tumor homogenates. Nevertheless, they are not associated with hypersecretion of pituitary hormones. To further clarify hormone synthesis in such pituitary adenomas, the presence of messenger ribonucleic acid (mRNA) of prolactin (PRL) growth hormone, and adrenocorticotropic hormone (ACTH) in the cytoplasm of 16 nonfunctioning adenomas was determined by means of a hybridization technique, and compared to the immunocytochemical findings. In three adenomas (19%) PRL mRNA was detected and in one case (6%) ACTH mRNA was detected. The hybridization technique appears to be more sensitive than immunohistochemistry for detection of specific mRNA's in assigning the hormone synthesis potential to clinically nonfunctioning tumors. The results suggest that PRL and ACTH are synthesized in some cases of clinically nonfunctioning pituitary adenomas and that hybridization techniques are useful to investigate hormone synthesis in pituitary adenomas. The ability to demonstrate PRL mRNA in tumor tissues allowed differentiation between hyperprolactinemia caused by synthesis of PRL in the tumor and that due to hypersecretion from the adjacent normal pituitary.

Adenoma↗
PubMed1987

The mode of hepatitis B virus DNA integration in chromosomes of human hepatocellular carcinoma.

Nineteen DNA samples that carry integrated hepatitis B virus (HBV) DNA were isolated from seven independent human hepatomas by molecular cloning, and their structures were determined. The results, combined with reported data, were analyzed so that one can obtain insights into the mechanisms of integration of this virus DNA and possible rearrangements that occur subsequently. The distribution of DNA junctions along the virus genome suggests that there are recombination-proficient regions. Thus, about half of the integrants were the Coh type, viz., one of their virus-cell DNA junctions fell within the so-called cohesive end region that lies between two 11-bp direct repeats (DR1 and DR2) in the virus genome where transcription and replication of the genome are initiated. All the integrated virus genomes were defective at least in one site around the cohesive end region, particularly within the X gene. The recombination-proficient regions are used not only for formation of virus-cell but also of virus-virus junctions. Neither virus nor cell DNA show unique sequences at the junctions, and targets for integration lie on many different chromosomes.

Base Sequence↗
PubMed1987

Chromosomal translocation and inverted duplication associated with integrated hepatitis B virus in hepatocellular carcinomas.

Integrated hepatitis B virus (HBV) DNA is found in hepatocellular carcinomas which develop in HBV carriers. Presented here are the results of analyses of four integrants that show chromosomal rearrangements associated with the integrated HBV DNA. Two clones (p4 and C15) were found to have large inverted repeating structures, each consisting of HBV genome along with flanking cellular sequences. The structure must have arisen by duplication of the primary integrant, including the flanking cellular DNA, followed by recombination within the viral DNA. One of the two viral arms in each clone joins to the other viral arm at the "cohesive end region." Two clones (DA2-2 and DA2-6) were found to have integrated HBV sequences, each flanked by cellular DNAs from different chromosomes (chromosome X joined to 17 and chromosome 5 joined to 9). They must be the products of cellular DNA translocations using the integrated HBV DNA as the switch point. The viral DNA in each clone is a continuous stretch of a single virus genome with one end in the cohesive end region. These complex structures seem to have been produced by activation of the cohesive end of an integrant viral genome, followed by its recombination with another chromosomal DNA.

Base Sequence↗
PubMed1987

Bilateral middle cranial fossa arachnoid cysts.

A rare case of bilateral arachnoid cysts of the middle cranial fossa in a child successfully treated by partial excision of their walls is reported. Patients with bilateral arachnoid cysts are usually severely disabled, presumably due to primary dysgenesis of the operculum; however, in our case no primary dysgenesis was noted and the operative result was excellent.

Arachnoid↗
PubMed1987

A case with spasm of a saphenous vein graft.

A 54-year-old man developed angina pectoris 18 months after a successful aortocoronary bypass graft. The angiogram demonstrated patent grafts and no significant changes in the native coronary vessels. However, ergonovine maleate provoked spasm in a saphenous vein graft.

Coronary Angiography↗
PubMed1987

[Papillary muscle infarction: echocardiographic features and genetic factors].

To study the pathogenesis of papillary muscle infarction, its echocardiographic features were examined in 60 patients with old inferior infarction. Sixty-three healthy elderly persons served as the controls. 1. The papillary muscles were echocardiographically classified as fingerlike and non-fingerlike in configuration whose frequencies were 43% and 57%, respectively. In healthy subjects, the papillary muscles were less echogenic than the left ventricular wall. 2. In five patients, the posteromedial papillary muscle exhibited enhanced echo intensity and no contraction. The papillary muscles in two of these five patients were histologically examined and the diagnosis of papillary muscle infarction was verified. In these five patients, the papillary muscles were echocardiographically classified as fingerlike, and left ventricular infarction was observed to involve the attachment of the posteromedial papillary muscle. All five patients had mitral valve prolapse; posterior in four and anterior in one. Inferior infarction extended to the region just beneath the mitral annulus in the former four patients, but not in the latter one. 3. The echocardiographic features of papillary muscle infarction consisted of enhanced echo intensity of the papillary muscle and mitral valve prolapse, especially that of the posterior leaflet at the posteromedial commissural side, and extension of the asynergy region to the attachment portion of the papillary muscle. The fingerlike morphology of the papillary muscle and involvement of the attachment within the infarcted region are predispositions to the development of papillary muscle infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

No increase in sister-chromatid exchange frequency in lymphocytes of chromium platers.

To detect mutagenic effects of hexavalent chromium (Cr) in vivo, sister-chromatid exchange (SCE) frequency was analyzed in lymphocytes of 24 Cr platers occupationally exposed to hexavalent Cr and 24 matched controls. There were no significant differences in SCE frequency between the two groups. Smokers, both Cr platers and controls, had a significantly higher SCE frequency than non-smokers.

Adult↗
PubMed1986

Spontaneous and induced sister chromatid exchanges in lymphocytes of healthy persons.

Spontaneous and mitomycin C-induced sister chromatid exchanges (SCEs) in lymphocytes were analyzed in 46 healthy persons. Our results suggest that the frequency of spontaneous SCE in lymphocytes is useful for evaluation of the biological effects of environmental mutagens, and that the induced-SCE test with a mutagen and lymphocytes may be used to detect persons with a high sensitivity to the mutagen.

Adult↗
PubMed1986

T loop in posterior myocardial infarction: a useful clue to vectorcardiographic diagnosis.

In order to differentiate posterior (posterolateral) myocardial infarction (PMI) from the anterior shift of the QRS loop in "normal variant" cases using a vectorcardiogram, the T loop as well as the QRS loop in the transverse plane (TP) were analyzed in 34 elderly Japanese males with angiographically-proven PMI and in 197 elderly Japanese males with normal coronary arteries and ventricles. T loops in the TP were longer, narrower and more anterior in PMI cases. After this analysis, we propose new criteria for PMI: (A and B) A: maximal T vector equal or anterior to 60 degrees in TP B: at least two of the following three: maximal QRS voltage/maximal T voltage in TP equal to or less than 3.0; QRS-T angle equal to or less than 75 degrees in TP; width/length of T equal to or less than 0.15 in TP. These new criteria for PMI are more specific (p less than 0.01) and more sensitive (p less than 0.05) than Hoffman's criteria.

Adult↗
PubMed1986

Analysis of the evolution of coronary artery disease--evaluation of 227 cases by restudy of coronary arteriography.

Some 227 patients who showed a 50% or greater narrowing of at least one major coronary artery in the first study underwent recatheterization at a mean interval of 35.6 months. Coronary arterial lesions and the degree of narrowing [i.e., normal (absent), 25%, 50%, 75%, 90%, 99% and complete occlusion (100%)] were classified in accordance with the AHA reporting system. When the lesions in the second study showed a change of equal or more than 2 in the above 7 stages in comparison with the first study, either progression or regression was determined. Of the 227 patients, progression occurred in 73 (32%) and regression was found in 7 (3%). In the aggravated group in symptom, progression was noted in 58%, and even in the stabilized group, progression was observed in 22%. As a result of the second study, 15 (21%) out of 73 patients showing progression underwent surgical treatment, and more than half of these cases (9/15) were constituted by the stabilized group. During the above follow-up periods, myocardial infarction occurred subsequently in 14 (19%) out of 73 patients showing progression. Up to the present time, sudden deaths occurred in 8 patients, and 5 out of 8 patients were also of the stabilized group. The authors wish to emphasize from these findings the necessity of aggressively pursuing restudy even in stabilized cases showing symptoms of ischemic heart disease.

Adult↗
PubMed1986

Is it possible to rule out extensive anterior myocardial infarction in the absence of abnormal Q waves in lead I and aVL? Effect of infero-apical extension of infarction over apex.

To determine whether abnormal Q wave in lead I or aVL may be of use to estimate the size of an extensive anterior myocardial infarction, electrocardiographic and left ventriculographic findings were analyzed in 45 patients with old extensive anterior infarction. All 45 patients had a significant narrowing in the proximal segment of left anterior descending coronary artery (LAD) and severe asynergy in anterolateral segment. The patients were divided into two groups; Group I consisted of 35 cases with less involvement of the inferoapical segment and Group II of 10 cases with remarkable extension of the anterolateral infarction into the inferoapical segment due to occlusion of very long LAD supplying the anterior half of posterior interventricular groove. There were no statistical differences in the extent of anterolateral asynergy, number of abnormal Q waves in precordial leads and left ventricular ejection fraction between the two groups. While abnormal Q wave in lead I or aVL was present in 28 cases (80%) of Group I, it was observed in only 3 cases (30%) of Group II (p less than 0.01). Thus, we can't rule out extensive anterior myocardial infarction even if abnormal Q waves are absent in lead I or aVL, in which abnormal Q waves may be cancelled by loss of electromotive force of inferoapical segment due to extension of the anterior infarction over the apex in cases with extraordinarily long LAD.

Electrocardiography↗