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Biomedical subjects

F Kishi

Publications and source records attributed to F Kishi.

At least 109 records · Page 6Linked to original sources
PubMed1987

Isolation and characterization of two types of cDNA for mitochondrial adenylate kinase and their expression in Escherichia coli.

Two cDNA clones for mitochondrial adenylate kinase were isolated from a cDNA library of bovine liver poly(A)+ RNA by using synthetic oligodeoxynucleotides as probes. The clone containing a 0.9-kilobase insert had the reading frame for a 241-residue protein (AK2A), while the other clone containing a 1.6-kilobase insert had the frame for a 234-residue protein (AK2B). Nucleotide sequences of these two clones were the same in the 5' portion up to the coding sequence for the 233rd residue, but different in the remaining 3' portions. The reported amino acid sequence of mitochondrial adenylate kinase from bovine heart corresponded to AK2A. Neither AK2A nor AK2B had a cleavable NH2-terminal presequence as that found in other imported mitochondrial proteins. RNA blot analysis of poly(A)+ RNAs from bovine liver and heart revealed three species of mRNA with approximate sizes of 0.9, 1.4, and 1.7 kilobases. The 1.7- and 1.4-kilobase species were specific for AK2B, whereas the 0.9-kilobase species was specific for AK2A. In the liver, the 1.7-kilobase mRNA was more abundant, whereas in the heart the 0.9-kilobase mRNA was predominant. The 1.4-kilobase mRNA was present only in the heart. The AK2A- and AK2B-coding sequences were expressed in Escherichia coli cells under the control of trc promoter. Both the products reverted the temperature-sensitive phenotype of the adenylate kinase mutant of E. coli.

Adenylate Kinase↗
PubMed1987

Isolation of a novel cDNA clone for human tyrosine hydroxylase: alternative RNA splicing produces four kinds of mRNA from a single gene.

Human tyrosine hydroxylase (TH) cDNA was isolated by molecular cloning. Lambda gt 11 cDNA library constructed from human pheochromocytoma was screened with a synthetic 23-mer oligonucleotide complementary to rat TH mRNA. We found a novel type of cDNA clone whose N-terminal sequence is similar to but clearly distinct from each of the three types (type 1, 2 and 3) of TH cDNA reported by Grima et al. [Nature (1987) 326, 707-711]. It contains both the 12-bp insert characteristic of type 2 cDNA and the 81-bp sequence of type 3. This novel cDNA clone was designated as type 4. Southern blot analysis of human genomic DNA indicated that TH is encoded by a single gene. This suggests that the four different forms of TH mRNA are produced by alternative RNA splicing from a single primary transcript.

Adrenal Gland Neoplasms↗
PubMed1987

High level expression of chicken muscle adenylate kinase in Escherichia coli.

Chicken muscle adenylate kinase was produced in a large amount in Escherichia coli cells harboring an expression plasmid, pKK-cAKl-1. The plasmid was constructed by placing the cDNA sequence for chicken muscle adenylate kinase after the tac promoter. After induction by isopropyl-beta-D-thiogalactopyranoside, the enzyme protein amounted to about 10% of the bacterial proteins. The enzyme was readily purified in two steps by using phosphocellulose and Sephadex G-100 columns. The apparent molecular weight of the enzyme produced in E. coli was estimated to be 22,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, in agreement with the value deduced from the cDNA sequence. Ten amino acids in the NH2-terminal region were determined, and were identical with the sequence deduced from the cDNA sequence except that the terminal methionine was absent. Michaelis constants for ATP, ADP, and AMP of the enzyme thus synthesized were essentially identical to those determined with the enzyme in crude extracts of chicken skeletal muscle.

Adenylate Kinase↗
PubMed1987

Effect of brain blood flow on hypoxic ventilatory response in humans.

To assess the effect of brain blood flow on hypoxic ventilatory response, we measured arterial and internal jugular venous blood gases and ventilation simultaneously and repeatedly in eight healthy male humans in two settings: 1) progressive and subsequent sustained hypoxia, and 2) stepwise and progressive hypercapnia. Ventilatory response to progressive isocapnic hypoxia [arterial O2 partial pressure 155.9 +/- 4.0 (SE) to 46.7 +/- 1.5 Torr] was expressed as change in minute ventilation per change in arterial O2 saturation and varied from -0.16 to -1.88 [0.67 +/- 0.19 (SE)] l/min per % among subjects. In the meanwhile, jugular venous PCO2 (PjCO2) decreased significantly from 51.0 +/- 1.1 to 47.3 +/- 1.0 Torr (P less than 0.01), probably due to the increase in brain blood flow, and stayed at the same level during 15 min of sustained hypoxia. Based on the assumption that PjCO2 reflects the brain tissue PCO2, we evaluated the depressant effect of fall in PjCO2 on hypoxic ventilatory response, using a slope for ventilation-PjCO2 line which was determined in the second set of experiments. Hypoxic ventilatory response corrected with this factor was -1.31 +/- 0.33 l/min per %, indicating that this factor modulated hypoxic ventilatory response in humans. The ventilatory response to progressive isocapnic hypoxia did not correlate with this factor but significantly correlated with the withdrawal test (modified transient O2 test), which was performed on a separate day. Accordingly we conclude that an increase in brain blood flow during exposure to moderate hypoxia may substantially attenuate the ventilatory response but that it is unlikely to be the major factor of the interindividual variation of progressive isocapnic hypoxic ventilatory response in humans.

Carbon Dioxide↗
PubMed1987

Relationship between the ability to detect added resistance at rest and breathlessness during bronchoconstriction in asthmatics.

The ability to detect added resistance at rest was compared to the magnitude of breathlessness (evaluated by a modified Borg scale) during bronchoconstriction in 27 stable asthmatics. Threshold for resistive load detection was analyzed in terms of the Weber fraction (delta R/R0) and mouth pressure (P) at the threshold. Bronchoconstriction was induced by inhalation of aerosolized acetylcholine. Both delta R/R0 and P correlated inversely with the Borg score during bronchoconstriction (r = -0.537 and r = -0.689, respectively; p less than 0.01). On the other hand, during bronchoconstriction the Borg score did not correlate with increased lung volume, acute changes in arterial blood gas composition and drive and timing component of ventilation during bronchoconstriction, although bronchoconstriction caused significant changes in these variables. These results indicate that central processing of afferent stimuli rather than peripheral sensor contribute both to the ability to detect added resistance at rest and to the magnitude of breathlessness during bronchoconstriction in asthmatics.

Acetylcholine↗
PubMed1986

Isolation and characterization of cDNA for chicken muscle adenylate kinase.

A cDNA clone for muscle adenylate kinase was isolated from a cDNA library of chick skeletal muscle poly(A)+ RNA, and the DNA sequence was determined. The cDNA insert had 854 nucleotides, which consisted of the 5'-untranslated sequence of 57 nucleotides, the sequence of 582 nucleotides coding for 194 amino acids, and the 3'-untranslated sequence of 163 nucleotides and the poly(A) tail of 52 nucleotides. The amino acid sequence predicted from the nucleotide sequence was highly homologous with the reported sequences of human, calf, porcine, and rabbit muscle adenylate kinases. RNA blot analysis of poly(A)+ RNA from various chicken tissues revealed a single species of mRNA of approximately 850 nucleotides and its tissue-specific distribution. The induction of muscle adenylate kinase mRNA synthesis during the chick embryogenesis was also demonstrated by the blot analysis. Southern blot analysis indicated a single gene for muscle adenylate kinase in the chicken genome.

Adenylate Kinase↗
PubMed1985

Development of myokinase mRNA during embryogenesis of the chick.

During chick embryogenesis, the mRNA for myokinase, as determined by in vitro translation, appears on the 16th day. The mRNA levels do not change drastically in succeeding stages and increase immediately after hatching. In contrast, myokinase activity and its protein gradually increase from the 16th day. Thus, myokinase mRNA that is translatable in vitro seems to accumulate transiently in the late stage of embryogenesis. In sucrose density gradient centrifugation, the mRNA sedimented as one peak with a coefficient of 10S.

Adenylate Kinase↗
PubMed1985

Acute inhalation of cigarette smoke augments hypoxic chemosensitivity in humans.

Hypoxic and hypercapnic ventilatory responses were measured after two levels of acute inhalation of cigarette smoke, minimum-level nicotine smoke (smoke 1) and nicotine-containing smoke (smoke 2), in 10 normal men. Chemosensitivity to hypoxia and hypercapnia was assessed both in terms of slope factors for ventilation-alveolar PO2 curve (A) and ventilation-alveolar PCO2 line (S) and of absolute levels of minute ventilation (VE) at hypoxia or hypercapnia. Ventilatory response to hypoxia and absolute level of VE at hypoxia significantly increased from 23.5 +/- 22.6 (SD) to 38.6 +/- 31.3 l . min-1 . Torr and from 10.6 +/- 2.5 to 12.6 +/- 3.5 l . min-1, respectively, during inhalation of cigarette smoke 2 (P less than 0.05). Inhalation of cigarette smoke 2 tended to increase the ventilatory response to hypercapnia, and the absolute level of VE at hypercapnia rose from 1.42 +/- 0.75 to 1.65 +/- 0.58 l . min-1 . Torr-1 and from 23.7 +/- 4.9 to 25.5 +/- 5.9 l . min-1, respectively, but these changes did not attain significant levels. Cigarette smoke 2 inhalation induced an increase in heart rate from 64.7 +/- 5.7 to 66.4 +/- 6.3 beats . min-1 (P less than 0.05) during room air breathing, whereas resting ventilation and specific airway conductance did not change significantly. On the other hand, acute inhalation of cigarette smoke 1 changed none of these variables. These results indicate that hypoxic chemosensitivity is augmented after cigarette smoke and that nicotine is presumed to act on peripheral chemoreceptors.

Adult↗
PubMed1984

[Mechanisms of high hemoglobin A1 in alcohol drinkers].

Hemoglobin A1 (HbA1) levels were significantly higher in healthy alcohol drinkers (HbA1 = 7.50%, n = 11) than in normal non-drinkers (HbA1 = 6.62%, n = 13). Ethanol was not able to change HbA1 level when ethanol was added to human whole blood in vitro. Acetaldehyde (AcCHO), although, markedly increased it. Glucose utilization in erythrocytes was stimulated by AcCHO. While it was completely blocked by sodium fluoride in the presence of AcCHO in the incubation medium, but sodium fluoride did not affect the formation of HbA1. AcCHO formed HbA1 with human purified hemoglobin in vitro. The level of HbA1 formed by AcCHO was significantly low when purified human hemoglobin used as a substrate in comparison with the use of whole blood. AcCHO and dihydroxyacetone phosphate reacted in the presence of aldolase. The reacted product, 5-deoxy-D-xylulose-1-phosphate, increased HhA1 level of human purified hemoglobin. It is suggested, the high level of HbA1 in healthy drinkers was caused by AcCHO, the first metabolite of ethanol. AcCHO formed addicts with human hemoglobin directly, and there might be other mechanisms of HbA1 formation due to AcCHO, such as 5-deoxy-D-xylulose-1-phosphate, which is the reacted product of AcCHO.

Acetaldehyde↗