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Biomedical subjects

Y Eguchi

Publications and source records attributed to Y Eguchi.

At least 181 records · Page 10Linked to original sources
PubMed1988

Cleavage of bacteriophage phi 80 CI repressor by RecA protein.

We have purified the CI repressor protein of bacteriophage phi 80. Its N-terminal amino acid sequence and its amino acid composition agree with those predicted from the nucleotide sequence of the cI gene. The phi 80 CI repressor was cleaved at a Cys-Gly bond by the wildtype RecA protein in the presence of single-stranded DNA and ATP or its analogues. This cleavage site is different from other repressors such as LexA, lambda CI and P22 C2, which were cleaved at an Ala-Gly bond. The phi 80 CI repressor was cleaved at the same site by the RecA430 protein, but was not cleaved by the RecA1 protein. This effect of the bacterial recA mutations on cleavage is consistent with the fact that prophage phi 80 in recA430 cells can be induced by irradiation with ultraviolet light, while the prophage in recA1 cells cannot.

Amino Acid Sequence↗
PubMed1988

Lead levels in ancient and contemporary Japanese bones.

During the past few centuries, lead production, consumption and emissions, to our total environment have increased remarkably. We have determined the concentrations of lead in 41 well-preserved ancient and 11 contemporary rib bones of a mature age (40-60 y), with a view of historically evaluating lead exposure in humans. The oldest Japanese bones (1000-300 B.C.) were found to contain a mean of 0.58 microgram Pb/g dry wt and a mean molar ratio of lead to calcium of 0.6 x 10(-6), compared with 4.7-5.2 x 10(-6) in the bones of the Edo era (1600-1867 A.D.) and contemporary residents in Japan. The mean molar ratios of female bones were always higher than those of male bones for each era. From this fact we may assume that facial cosmetics were one of the main routes of lead exposure among the ancient Japanese, especially those who lived during the Edo era.

Adult↗
PubMed1988

Reverse phase high performance liquid chromatographic analysis of circulating insulin in the insulin autoimmune syndrome.

Some patients with the insulin autoimmune syndrome have circulating insulin that is heterogeneous. We used reverse phase high performance liquid chromatographic analysis to identify the forms of plasma insulin in patients with this syndrome and compared the results with those in patients with insulin-treated diabetes and patients with hyperinsulinism. Under acidic conditions, free insulin dissociated from insulin antibodies eluted from Bio-Gel P-30 columns as a single peak. When such insulin fractions were applied to reverse phase high performance liquid chromatography, a major insulin peak emerged with the same retention time as standard human insulin in all six patients with the syndrome. In addition, a minor insulin peak was consistently found at relatively high acetonitrile concentrations. However, this hydrophobic insulin also was found in two of four insulin-treated diabetic patients and in one of two hyperinsulinemic patients who did not have insulin antibodies. Preliminary characterization of the variant insulin revealed that it has a molecular size between those of proinsulin and insulin and retains the immunoreactivity of insulin, but not C-peptide. It may be an aggregate of insulin molecule or proinsulin intermediates. Since the variant insulin was not found only in patients with the insulin autoimmune syndrome, it seems unlikely that an altered endogenously produced insulin induces the generation of autoantibodies to insulin in this syndrome.

Adult↗
PubMed1988

Supraventricular tachycardia in a patient with Lown-Ganong-Levine syndrome associated with apical hypertrophic cardiomyopathy.

Electrophysiologic study of a 55-year-old patient with Lown-Ganong-Levine syndrome associated with apical hypertrophic cardiomyopathy is reported. The patient had a history of recurrent attacks of tachyarrhythmia and his electrocardiogram showed a short P-R interval (0.10 sec) with narrow QRS complex and left ventricular hypertrophy with giant negative T waves. His cineangiogram showed severe apical hypertrophy. An electrophysiologic study was performed. The results of programmed atrial pacing show the existence of the dual A-V nodal pathways. The A-H interval at rapid atrial pacing increased maximally by 103 msec. Atrial stimulation could depolarize parts of the atrium without altering the supraventricular tachycardia. These findings suggested that preferential rapidly conducting A-V nodal and intranodal reentry are the responsible mechanisms in this reciprocating tachycardia. We conclude that the short P-R interval was due to intranodal reentry through the dual A-V nodal pathways. To our knowledge, a case of Lown-Ganong-Levine syndrome with apical hypertrophic cardiomyopathy has not been previously described in the literature.

Cardiac Catheterization↗
PubMed1987

Effect of thyrotropin-releasing hormone on development of the pituitary-thyroid system in fetal rats in organ culture.

Six groups of thyroid glands from 18-day fetal rats were explanted to organ culture for 2 days. In one group, thyroid was cultured alone and in the remaining five groups thyroid was cocultured with pituitaries from fetuses ranging in age from 17 to 21 days. In each of the groups, half of the cultures had thyrotropin-releasing hormone (TRH) added to the medium. Histometric parameters of the thyroid follicle such as diameter and cell height were used as indicators of development of the thyroid gland. When 18-day thyroid was cultured alone, addition of TRH did not accelerate development. When either one 18-day or two 17-day pituitaries were cocultured with thyroid, a significant increase in diameter and cell height was seen. Addition of TRH to the medium induced little or no further change. When the thyroid was cultured with 19- to 21-day pituitaries, a marked increase in thyroid development was observed; and the addition of TRH caused further acceleration in thyroid development. These results suggest that, in organ culture, 17- to 18-day pituitary glands can release some thyrotropin (TSH) with or without additional TRH. Older pituitaries (19- to 21-day) apparently can release an amount of TSH in the presence of TRH that is greater than their own spontaneous TSH secretion.

Animals↗
PubMed1987

Quantifiable morphologic evaluation of paraquat pulmonary toxicity in rats.

The intent of this study was to detect paraquat (PQ)-induced, dose-dependent variations, in rat lungs, by analyzing several quantifiable morphologic parameters. Male Wistar rats (6-week old) received single doses (0, 7, 10, 25 or 40 mg/kg body weight) of PQ dichloride by sc injection. The parameters examined were number of alveolar type II cells, number of intra-alveolar free cells, total number of cells constituting the pulmonary interstitium, and alveolar wall thickness. Our maximum dose produced a marked decrease, 3 days post-injection, in the number of alveolar type II cells in contrast to the observed increases in all other dosage groups. These increases in other groups were inversely proportional to the increasing PQ dosages. All rats that received the maximum dose died within 4 days after injection and therefore could not be compared to the control group for our parameters after 6 days. After 9 days, the number of type II cells had decreased significantly in the 25 mg/kg group. The two highest dosage groups, on the third day, had significantly more intra-alveolar free cells. The total number of cells constituting the pulmonary interstitium in all groups increased in proportion to the increasing dosages from 3 to 9 days post-injection. In the 10 and 25 mg/kg groups, alveolar wall thickness was notably increased from days 6 to 9. PQ dosing produced dose-dependent variations in all of the parameters examined. This model of PQ-induced pulmonary toxicity may be useful in evaluating prophylactic or therapeutic agents.

Animals↗
PubMed1986

Differentiation and thyroid-stimulating hormone (TSH) sensitivity of the fetal rat thyroid in organ culture.

Thyroids from rat fetuses of different ages (from day 14 to day 19 of gestation) were transplanted to organ culture for 2 days, with or without added thyroid-stimulating hormone (TSH) in the medium. Thyroid tissue from 14-day fetuses that initially consisted of irregularly arranged cell cords did not form follicles when cultured in the presence or absence of TSH. Thyroids from 15- and 16-day fetuses initially consisted of epithelial cell masses. When cultured in the presence or absence of TSH they formed follicles, and a majority stored small amounts of colloid. In thyroid transplants from 17-day fetuses, the response to TSH appeared as a significant increase in the follicular diameter and cell height. Thereafter, in all transplants cultured in the presence of TSH, both the follicular diameter and the cell height were markedly greater than in the transplants cultured in the absence of added TSH. These results suggest that the initial formation of thyroid follicles is independent of TSH and that, once developed, follicles become able to respond to TSH.

Animals↗
PubMed1986

The sensitivity of the fetal rat adrenal gland to adrenocorticotropic hormone in vivo and in vitro.

Rat fetuses were treated with 1 IU ACTH on day 16 or 17 of gestation and autopsied on the next day. Other fetuses of the same litter were treated with saline alone. The adrenal glands of ACTH-treated fetuses were significantly heavier than those of saline-treated fetuses and of intact controls in every experimental period. These changes in the weight of fetal adrenal glands reflect histologically on changes in the size of adrenocortical cells which were enlarged in response to injected ACTH. Adrenal glands from rat fetuses of different ages were explanted to organ cultures for 2 days, in medium with or without ACTH added. The 13-day adrenal glands were not able to respond to ACTH, but the response appeared abruptly in the 14-day adrenal glands, judging from the increased cell size in histological sections. The overall results suggest that the fetal adrenal gland begins to respond to ACTH from day 14 of gestation.

Adrenal Glands↗