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Biomedical subjects

K Aoyagi

Publications and source records attributed to K Aoyagi.

At least 271 records · Page 15Linked to original sources
PubMed1984

Pyruvate orthophosphate dikinase of c(3) seeds and leaves as compared to the enzyme from maize.

Pyruvate orthophosphate dikinase (PPDK) was found in various immature seeds of C(3) plants (wheat, pea, green bean, plum, and castor bean), in some C(3) leaves (tobacco, spinach, sunflower, and wheat), and in C(4) (maize) kernels. The enzyme in the C(3) plants cross-reacts with rabbit antiserum against maize PPDK. Based on protein blot analysis, the apparent subunit size of PPDK from wheat seeds and leaves and from sunflower leaves is about 94 kdaltons, the same as that of the enzyme from maize, but is slightly less (about 90 kdaltons) for the enzyme from spinach and tobacco leaves. The amount of this enzyme per mg of soluble protein in C(3) seeds and leaves is much less than in C(4) leaves. PPDK is present in kernels of the C(4) plant, Zea mays in amounts comparable to those in C(4) leaves.Regulatory properties of the enzyme from C(3) tissues (wheat) are similar to those of the enzyme from C(4) leaves with respect to in vivo light activation and dark inactivation (in leaves) and in vivo cold lability (seeds and leaves).Following incorporation of (14)CO(2) by illuminated wheat pericarp and adjoining tissue for a few seconds, the labeled metabolites were predominantly products resulting from carboxylation of phosphoenolpyruvate, with lesser labeling of compounds formed by carboxylation of ribulose 1,5-bisphosphate and operation of the reductive pentose phosphate cycle of photosynthesis. PPDK may be involved in mechanisms of amino acid interconversions during seed development.

Journal Article↗
PubMed1984

Pyruvate orthophosphate dikinase gene expression in developing wheat seeds.

The amount of pyruvate orthophosphate dikinase (PPDK) (EC 2.7.9.1) protein in wheat (Triticum aestivum L. var Cheyenne) grains was determined at different stages of development by the protein blot method. The variation in PPDK protein with time in developing wheat grains was similar to that of the enzyme's activity reported by Meyer et al. (1982 Plant Physiol 69: 7-10). The variation in levels of PPDK mRNA with seed development was determined by analysis of polypeptides immunoprecipitated by anti-PPDK serum from in vitro translation products of extracted seed RNA. This mRNA variation was similar to that of the in vivo enzyme levels and the correlation is consistent with the regulation of PPDK gene expression by the level of its mRNA.The highest level of PPDK in developing wheat seeds occurs later than the highest levels of both ribulose bisphosphate carboxylase (EC 4.1.1.39) and of chlorophyll, which are located in the green pericarp tissue. PPDK was located in both endosperm and pericarp tissue of the seeds. The tissue location and developmental profile of seed PPDK are consistent with a metabolic role of providing phosphoenolpyruvate as a substrate for recapturing respiratory CO(2) in the seed, and possibly for amino acid interconversions during development.

Journal Article↗
PubMed1984

Pyruvate orthophosphate dikinase mRNA organ specificity in wheat and maize.

Polyadenylated RNA was isolated from leaves and seeds of a C(3) plant (Triticum aestivum L. cv Cheyenne, CI 8885) and from a C(4) plant (Zea mays L. cv Golden bantam). Each polyadenylated RNA preparation was translated in vitro with micrococcal nuclease-treated reticulocyte lysate. When the in vitro translation products were probed with antibodies to pyruvate orthophosphate dikinase (PPDK) (EC 2.7.9.1), two sizes of polypeptide were identified. A 110 kilodalton polypeptide was found in the in vitro translation products of mRNA isolated exclusively from leaves of both wheat and maize. A 94 kilodalton polypeptide, similar to the PPDK polypeptide which can be extracted after in vivo synthesis in maize and wheat leaves and seeds, was found in the in vitro translation products obtained from wheat seeds and maize kernels.These results indicate that the mRNAs for PPDK polypeptides are organ-specific in both a C(4) and a C(3) plant. Hague et al. (1983 Nucleic Acids Res 11: 4853-4865) proposed that the larger size polypeptide of the in vitro translation polypeptide from maize leaf RNA contains a ;transit sequence' which permits entry into the chloroplasts of a polypeptide synthesized in vivo in maize leaf cell cytoplasm. It appears that in wheat leaves also the transit of synthesized PPDK polypeptide through an intracellular membrane may be required, while such a transit sequence seems not to be required within cells of wheat and maize seeds.

Journal Article↗
PubMed1984

A case of adult T-cell leukemia initiated with central nervous system symptoms.

We treated a 52-year-old Japanese woman with adult T-cell leukemia (ATL) initiated with central nervous system (CNS) symptoms. Her chief complaints were paraplegia and left facial palsy. CNS-ATL was diagnosed because of the following three features. 1) Various sized lymphoid cells with marked nuclear convolution were numerous in her cerebrospinal fluid. 2) These cells were a monoclonal proliferation of T lymphocytes with OKT 4 marker. 3) The patient's serum was positive for anti-ATL associated antigen (ATLA). Although the neurological signs and symptoms improved markedly after intrathecal administration of combined chemotherapy (methotrexate, cytarabine and corticosteroid), these ATL cells were highly resistant to radiation therapy. The abdominal mass which developed in the course of the disease was diagnosed as a tumor formed of ATL cells, and VEPA (vincristine, endoxan, prednisolone and adriamycin) was administered with marked success.

Antigens, Neoplasm↗
PubMed1983

[Serum type III procollagen peptide in patients with pneumoconiosis].

Early diagnosis of lung fibrosis has been hampered by the lack of a simple, convenient and specific method. Recently Rohde et al. developed an assay method for Type III procollagen peptide. Type III procollagen peptide, an extension peptide released during the biosynthesis of collagen Type III, has been known as a good marker for hepatic fibrosis. Therefore, we applied this assay to the patients with idiopathic pulmonary fibrosis, lung fibrosis in collagen disease and silicosis. And also we measured the serum level of the peptide in the healthy workers being exposed to silica. Normal value of the peptide in adults was 8.3 +/- 2.6 (mean +/- SD; n = 32) ng/ml. The upper value over mean + 2SD, 13.4 ng/ml, was regarded as abnormal value. Six patients with idiopathic pulmonary fibrosis, and lung fibrosis in collagen disease showed a significant increased level of 19.0 +/- 9.6 ng/ml (P less than 0.02). Four of 6 patients had abnormal high values. On the other hand, the patients with silicosis had not so high levels of peptide (12.6 +/- 6.5 ng/ml; n = 24; P less than 0.01), but 25% of the patients showed abnormal values. There were 2 cases among 19 healthy workers being exposed to silica who revealed slight abnormal values, 15.6 and 16.7 ng/ml. These observations suggest that the assay has a prognostic value for lung fibrosis and also is useful for the early detection of active lung fibrosis in the workers, even though Type III procollagen biosynthesis is already low in the late stages of silicosis.

Adult↗
PubMed1983

[Fasting serum gastrin, motilin and secretin in treated and untreated hyperthyroidism].

To study the gastrointestinal hormones involved in hyperthyroidism and the interrelationship with the thyroid hormones, the preprandial serum concentrations of gastrin, motilin and secretin were measured by radioimmunoassay in 33 normal subjects and in 104 patients before and after treatment. The following results were obtained. 1) Serum gastrin concentrations in hyperthyroid patients were significantly higher than that of the control, and when the patients reached euthyroidism or hypothyroidism after treatment, the gastrin concentrations in the serum decreased to the normal level. There was a positive correlation between thyroid hormones and serum gastrin. 2) The changes in serum motilin concentrations in hyperthyroidism before and after treatment did not show any significant differences from that of the control. There was a slightly negative relationship between motilin and gastrin and also between T4 and motilin. 3) The mean serum secretin level rose significantly in hypothyroid patients after treatment for hyperthyroidism, but there was no individual correlation between serum secretin and thyroid hormone.

Adult↗
PubMed1983

Hormonal response to insulin-induced hypoglycemia in patients with Shy-Drager syndrome.

We examined the response of plasma glucose concentration and glucose counterregulatory factors (eg, glucagon, epinephrine, growth hormone, cortisol, and norepinephrine) to insulin-induced hypoglycemia in four patients with Shy-Drager syndrome and in five control subjects to determine if glucose counterregulation occurred in the patients with sympathetic and parasympathetic nervous system defects. The recovery of plasma glucose from hypoglycemia in a slower phase in the patients appeared to be almost similar to that in the control subjects, along with the absence of an initial rapid recovery phase; that is, there was no significant difference in the plasma glucose levels observed at any point between the patients and the control subjects. Although the insulin-induced hypoglycemia in the control subjects provoked a rapid release of epinephrine, followed by an increase in the plasma glucagon, growth hormone, and cortisol levels, it did not cause a significant increase in any of the glucose counterregulatory factors in the patients. Our findings that the restoration of normoglycemia after insulin-induced hypoglycemia occurred despite no significant increase in the counterregulatory hormonal factors suggest that other glucose counterregulatory mechanisms (eg, increased glucose release from the liver by the intrinsic effect of hypoglycemia on the liver) than the hormonal glucose counterregulatory factors might play an important role in the recovery of plasma glucose from insulin-induced hypoglycemia in a state of chronic deficiency of hormonal factors.

Autonomic Nervous System Diseases↗
PubMed1983

Pituitary-adrenocortical system in patients with Shy-Drager syndrome.

We examined ACTH responses to the three main mechanisms of ACTH secretion, i.e., stress, negative feedback and circadian rhythm, in six patients with Shy-Drager syndrome and in six control subjects to determine whether or not injury to the central autonomic nervous system provokes some disturbances in ACTH secretion. The patients showed a poor cortisol response to the stress of insulin induced hypoglycemia along with a normal ACTH and urinary 17-OHCS response to metyrapone and a normal cortisol circadian rhythm. The discrepancy between the above-mentioned functional tests of ACTH secretion is rare to our knowledge. These findings suggested the existence of a glucoreceptor defect in such patients, or the possibility that the stress of insulin induced hypoglycemia stimulates ACTH secretion by way of the autonomic nervous system.

Adrenocorticotropic Hormone↗
PubMed1983

The mechanism of aldosterone response to furosemide test in patients with Shy-Drager syndrome.

We examined the renin-angiotensin-aldosterone system in seven patients with Shy-Drager syndrome by studying their response to the stimulation of 1 mg/kg furosemide injection followed by sitting for 1 hour. Six of the seven patients showed a low response of plasma renin activity to the stimulation. However, in five of the low responders, the plasma aldosterone levels after stimulation were observed to be similar to those of the control subjects; in addition, an increment in the plasma cortisol level appeared although no such increment was observed in normal subjects. Next, we studied the aldosterone response to angiotensin II. The five patients who showed a low plasma renin activity response and a normal aldosterone response to furosemide administration also showed low plasma aldosterone response to angiotensin II. Furthermore, in the patients who demonstrated a low plasma renin activity response and a normal aldosterone response to furosemide administration, the pretreatment with 2 mg dexamethasone for 2 days caused a marked inhibition of aldosterone response to the stimulation. These findings suggested that in most patients with Shy-Drager syndrome, the plasma aldosterone response to the stimulation of furosemide injection followed by sitting for 1 hour might be controlled by ACTH but not by plasma renin activity.

Adult↗
PubMed1983

Pyruvate orthophosphate dikinase in wheat leaves.

Pyruvate orthophosphate dikinase (PPDK) was found in wheat (Triticum aestivum L. cv Cheyenne [CI 8885]) leaves both by activity assays and by the protein blot method. The specific activity of the wheat enzyme is comparable to that of PPDK from maize leaves. Of the total soluble protein in wheat leaves, about 0.05% was PPDK, comparable to the amount in the immature wheat seed and about 1/70th the amount found in mesophyll cells of maize. Immunoprecipitation of wheat PPDK with maize enzyme antiserum indicates partial identity, and the apparent subunit molecular weight is the same based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Journal Article↗
PubMed1983

Renin-angiotensin system and plasma aldosterone in Cushing's syndrome.

The renin-angiotensin system was studied in eight patients with Cushing's syndrome (four with adrenal adenoma and four with adrenal hyperplasia) and in five normal controls. Basal plasma renin activity (PRA) and aldosterone concentration (PAC) were similar in supine position among Cushing's syndrome due to adrenal adenoma (PRA; 1.0 +/- 0.3 ng/ml/h, PAC; 7.4 +/- 1.0 ng/dl, mean +/- SE), those due to adrenal hyperplasia (1.0 +/- 0.2, 6.9 +/- 0.8) and the controls (0.8 +/- 0.1, 6.4 +/- 0.4). The PRA after furosemide (1 mg/kg i.v.) and 120 min. upright posture stimulation was similar among Cushing's syndrome due to adrenal adenoma (2.2 +/- 0.7 ng/ml/h), those due to adrenal hyperplasia (2.6 +/- 1.7) and the controls (2.5 +/- 1.2). However, the PAC response after the stimulation in Cushing's syndrome due to adrenal hyperplasia (7.1 +/- 1.2 ng/dl) was significantly lower than that in the controls (17.5 +/- 2.1) (p less than 0.01), although there was no significant difference between the PAC response in Cushing's syndrome due to adrenal adenoma (12.6 +/- 1.0) and the controls. These results indicate that PAC response to furosemide and upright pasture stimulation might be suppressed in Cushing's syndrome due to adrenal hyperplasia.

Adenoma↗