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Biomedical subjects

T Hironaka

Publications and source records attributed to T Hironaka.

At least 37 records · Page 2Linked to original sources
PubMed1992

Increased sensitivity for detection of human cytomegalovirus in urine by removal of inhibitors for the polymerase chain reaction.

The presence of inhibitors in urine interferes with the enzymatic reaction of the polymerase chain reaction (PCR) for detection of human cytomegalovirus (HCMV). To remove inhibitors, HCMV virions in urine were precipitated with polyethylene glycol, or DNA was extracted from urine by the use of glass powder and subjected to PCR followed by Southern blot hybridization with alkaline phosphatase-linked oligonucleotide probes. These simple, rapid methods increased significantly the sensitivity of PCR for detection of HCMV in urine.

Base Sequence↗
PubMed1992

Poly(ADP ribose) polymerase-defective mutant cell clone of mouse L1210 cells.

By a sequential mutation and selection utilizing N-methyl-N'-nitro-N-nitrosoguanidine as a mutagen, we succeeded in separating a poly(ADP ribose) polymerase-defective mutant clone (Cl-3527) from a mouse L1210 cell clone (Cl-3). The enzyme activity per cell in Cl-3527 cells was only 8% of that in wild type L1210 (CCL 219) cells. Immunoblot analysis of the enzyme protein in crude extracts of the mutant and wild type cells revealed that the enzyme defect was manifested as the loss of a 113-kDa wild type enzyme band in Cl-3527. Further analysis of partially purified enzyme from Cl-3527 by immunoblotting revealed that the molecular size of the enzyme in Cl-3527 was 108 kDa and that the amount of the mutant enzyme protein was markedly decreased in Cl-3527. The mutant enzyme was much more heat-labile than the wild type enzyme but the Km for NAD+, requirements for Mg2+ and nicked DNA, and the inhibition by 3-aminobenzamide, a potent inhibitor of the enzyme, however, were not so different from those of wild type enzyme. The mutant cells showed prolonged doubling time, increased temperature-sensitivity, increased percentage of active enzyme on a treatment of cells at high temperature, and increased expression of plasma membrane NADase, compared to wild type cells. Introduction of wild type ADPR pol gene into Cl-3527 cells partially restored the ADPR pol activity and the heat-resistance.

Animals↗
PubMed1991

Acute erythroleukemia with t(3;5) accompanied by hepatocellular carcinoma.

A female patient in whom acute nonlymphocytic leukemia (ANLL, FAB-M6) developed during treatment of hepatocellular carcinoma (HCC) is described. Two years after partial hepatectomy and subsequent chemotherapy, leukemia developed following a 2 month preleukemic stage. Chromosomal analysis revealed an abnormal karyotype, 46,XX,-5, + der(5)t(3;5)(q25;q31). The balanced translocation t(3;5) has been observed in all types of ANLL and MDS except for ANLL M3 subtype. We summarize patients with ANLL M6 and t(3;5).

Aclarubicin↗
PubMed1990

Ontological study of calbindin-D28k-like and parvalbumin-like immunoreactivities in rat spinal cord and dorsal root ganglia.

The calcium ion plays an important role in some critical developmental events in the nervous system, such as neurulation and neurite elongation. Therefore, as the intracellular calcium-binding proteins calbindin-D28k (CaB) and parvalbumin (PV) may be expressed in these developmental events. Accordingly, the ontological expression of CaB and PV was examined immunocytochemically in the spinal cord and dorsal root ganglia (DRG) of the rat, in order to evaluate the relationship between CaB and PV expression, and other important developmental events. During the ontogenesis of the spinal cord, the CaB-like immunoreactivity was mainly observed in the cell somata. The immunoreactive cells in the ventral horn of the cervical and thoracic, lumbar, and sacral segments first appeared at embryonic day (E)-12, E-13, and E-14, respectively. However, these cells were not detected in the intermediate gray matter of the same segments at E-14, E-15, and E-16, respectively, and in the dorsal horn at E-14-E-15, E-16, and E-17, respectively. The peak of immunoreactive cells, both as to number and intensity, occurred in the perinatal period. However, from postnatal day (P)-14 on, the number and intensity of the positive cells decreased, the adult levels being reached at P-35. The PV-like immunoreactivity was mainly detected in the fibers and punctata during the ontogenesis of the spinal cord. The immunoreactive fibers first appeared on the surface of the dorsal horn in the cervical and thoracic segments at E-14, then entered the dorsal horn at E-15, and reached the intermediate gray matter and ventral horn at E-16. The first appearance of these fibers in the same areas of the lumbar and sacral segments occurred 1 day later than in the cervical and thoracic segments. During the perinatal period, the maximum content of PV-like immunoreactive fibers, together with many punctata, was seen in the gray matter. However, between P-14 and P-17, most of them lost immunoreactivity rapidly, with the exception of the medial region of the intermediate gray matter, where the PV-immunoreactive punctata remained up to the adult stage. In DRG neurons, both CaB and PV was expressed, but in different neurons. Neurons labeled with anti-CaB and anti-PV sera were first detected at E-16 and E-14, respectively. These neurons were large or medium-sized in the prenatal period.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Postnatal development of preproenkephalin mRNA containing neurons in the rat lower brainstem.

Postnatal developmental changes of preproenkephalin (PPE) gene expression in rat brainstem neurons were studied by in situ hybridization histochemistry. On the basis of PPE mRNA expression, brainstem neurons were categorized into three types: 1) type I neurons were characterized by constant or increasing expression of PPE mRNA during postnatal development; 2) type II neurons started to express PPE mRNA several days after birth and continued to do so thereafter; and 3) type III neurons showed transient expression of PPE mRNA or stopped expressing the mRNA during early postnatal development. Type I PPE neurons were observed in diverse brainstem structures including the mesencephalic and pontine central gray matter, various reticular and raphe nuclei, the ventral tegmental area of Tsai, the interpeduncular nucleus, the nucleus of the brachium of the inferior colliculus, the ventral and dorsal tegmental nuclei of Gudden, the sphenoid nucleus, the laterodorsal tegmental nucleus, Barrington's nucleus, the parabrachial region, the lateral lemniscus and its related nuclei, the trapezoid nucleus, the rostral and ventromedial periolivary nuclei, the mesencephalic trigeminal and principal sensory trigeminal nuclei, the locus coeruleus, the subcoeruleus nucleus, the medial and spinal vestibular nuclei, the dorsal and ventral cochlear nuclei, the medial and lateral cerebellar nuclei, the Roller nucleus, and the intermedius nucleus of the medulla. Type II PPE neurons were found in the superior colliculus, the inferior colliculus, the central part of the dorsal tegmental nucleus, and as Golgi neurons in the granular layer of the cerebellum. Type III PPE neurons were located in the substantia nigra, the red nucleus, the superior olive, the motor trigeminal nucleus, the facial nucleus, the inferior olive, the dorsal motor nucleus of the vagus, and the hypoglossal nucleus. Such region-specific expression of the PPE gene during postnatal ontogeny suggests that rat brainstem PPE neurons may be involved in a variety of developmental events, such as cell proliferation, differentiation, and migration.

Aging↗
PubMed1990

Energetic recovery from hypothermic preservation in the rat liver.

Changes in energy metabolism induced by norepinephrine were observed in liver perfused immediately after dissection and in liver stored in Euro-Collins solution at 0 degrees C for 24 hr. Oxygen consumption, glucose output, ATP content, and tissue pH were measured in isolated perfused rat liver at 37 degrees C. In fresh liver, a two-fold increase in glucose output and oxygen consumption was induced by norepinephrine (1 microM), while changes in ATP content and tissue pH were minimal. In stored liver, the cumulative increments in glucose output and oxygen consumption induced by norepinephrine were 30 and 27% those of fresh liver, respectively. ATP content of the unstimulated liver was 76% that of the fresh liver, then decreased to 50% during stimulation. A transient decrease in tissue pH (0.14 pH unit) was significant compared with that of fresh liver. These results suggest that norepinephrine stimulation is useful for assessing energetic and functional recovery of reperfused liver following hypothermic storage.

Adenosine Triphosphate↗
PubMed1990

Localization of GABAA-receptor alpha 1 subunit mRNA-containing neurons in the lower brainstem of the rat.

The localization of gamma-aminobutyric acid-A (GABAA) receptors (GABAA-R) in the lower brainstem of the rat was examined by means of in situ hybridization histochemistry using an oligonucleotide probe to the sequence of the alpha 1 subunit (GABAA-R alpha 1). Strongly labeled neurons were found in the cranial motor nuclei, the dorsal motor nucleus of the vagus, reticular formation (large neurons), lateral vestibular nucleus, dorsal nucleus of the lateral lemniscus, central nucleus of the inferior colliculus, intermediate and white layers of the superior colliculus, red nucleus and substantia nigra. In addition, moderately labeled cells were abundant in the nucleus of the solitary tract, medial and inferior vestibular nuclei, parabrachial area, dorsal and ventral tegmental nuclei of Gudden, central gray matter, ventral nucleus of the lateral lemniscus, and reticular formation (small neurons). This study has therefore revealed some of the target neurons of GABA-containing fibers in the lower brainstem.

Animals↗
PubMed1989

Effects of valinomycin on calcium mobilization in vascular smooth muscle cells induced by angiotensin II.

The effect of the specific potassium (K+) ionophore valinomycin on increase in intracellular calcium concentration [( Ca2+]i) was studied in vascular smooth muscle cells (VSMC). Valinomycin at more than 10(-9) M dose-dependently suppressed phasic increase in [Ca2+]i in VSMC induced by angiotensin II (AII) in both control and Ca2+-free solution, indicating that it suppressed the release of Ca2+ from intracellular Ca2+ stores. Nicorandil and cromakalim, which are both K+ channel openers, also suppressed the increases in [Ca2+]i induced by AII in the Ca2+ free solution. However, valinomycin did not suppress AII-induced production of inositol 1,4,5-trisphosphate (IP3), which is known to mediate the release of Ca2+. These results indicate that decrease of intracellular K+ induced by valinomycin suppressed the release of Ca2+ from intracellular Ca2+ stores induced by IP3.

Angiotensin II↗
PubMed1989

Association of increased intracellular free Ca2+ by platelet-derived growth factor with mitogenesis but not with proteoglycan synthesis in chondrocytes--effect of suramin.

The effects of platelet-derived growth factor (PDGF) on the intracellular free Ca2+ concentration [( Ca2+]i) in chondrocytes were studied with a fluorescent Ca2+ indicator, fura 2, and compared with the effects of PDGF on mitogenesis and proteoglycan synthesis. PDGF evoked phasic and then tonic increase in [Ca2+]i dose-dependently in quiescent cultures of chondrocytes, and it also stimulated both DNA and proteoglycan syntheses dose-dependently similar to somatomedins. Suramin, which inhibits the interaction of PDGF with its receptors, caused dose-dependent inhibition of both the PDGF-evoked increase in [Ca2+]i and stimulation of DNA synthesis by PDGF. However, suramin rather enhanced the proteoglycan synthesis induced by PDGF without affecting the basal level of proteoglycan synthesis directly. These results suggest that [Ca2+]i may be an important signal for the action of PDGF on cell proliferation in chondrocytes, and that the initial signal for proteoglycan synthesis is different from that for DNA synthesis induced by PDGF after the activation of PDGF receptor.

Animals↗
PubMed1989

Relationship between the number of sperms and the rate of implantation in bitches inseminated into unilateral uterine horn.

Studies were made on the number of sperms required for fertilization of ova ovulated from the bilateral ovaries in bitches. The experiment was carried out with 44 female beagles, which were divided into four groups of seven to eleven bitches each. The four groups were inseminated with 40 X 10(6) sperms/0.2 ml, 20 X 10(6) sperms/0.1 ml, 10 X 10(6) sperms/0.1 ml, and 3-5 X 10(6) sperms/0.1 ml, respectively. All the bitches were laparotomized at an optimum time for mating and inseminated at the tip of the horn of an unilateral uterus. In the four groups conception took place at a rate of 7/7, 8/8, 10/11, and 2/7, respectively. The number of puppies exceeded the number of ova ovulated on the inseminated side at a rate of 5/7, 6/8, 0/10, and 0/2 in the four groups, respectively. Therefore, it was clarified that when more than 20 X 10(6) sperms/0.1 ml were inseminated in the ipsilateral uterine horn, ova ovulated on the contralateral side were fertilized also. Then a unilateral ovary was ovariectomized in 11 bitches, which were inseminated with 10 X 10(6) sperms/0.1 ml in the ipsilateral uterine horn. As a result, only one bitch became conceptive and gave birth to only one puppy. From these results, it was considered that 10 X 10(6) sperms/0.1 ml may be most adequate for the ova on the side of insemination alone to be fertilized.

Animals↗
PubMed1988

[Immunoreactive parathyroid hormones in the circulation and cerebrospinal fluid from patients with renal failure: possible restriction of parathyroid hormone by the blood-brain barrier].

There are reports that patients with renal failure have elevated circulating concentrations of parathyroid hormone (PTH), which is suspected to be a causal factor of the cerebral symptoms of these patients. A positive correlation between the circulating level of immunoreactive PTH and the extent of abnormality in the electroencephalogram (EEG) in humans has been reported. Moreover, in uremic dogs normalization of the EEG was observed after parathyroidectomy, and increased abnormality of the EEG was observed on infusion of PTH. If PTH is really a causal factor of uremic encephalopathy and abnormality of the EEG in patients with renal failure, the question arises as to whether PTH acts on the brain after penetrating through the blood-brain barrier or in some other way. In this work, we measured PTH by both C-terminal-specific RIA (C-PTH) and N-terminal-specific RIA (N-PTH) in the circulation and cerebrospinal fluid (CSF) of normal subjects and patients with renal failure. Blood and CSF samples were obtained from 7 normal volunteers (31 approximately 81 years old: 4 males and 3 females) and 22 patients with chronic renal failure (25 approximately 87 years old: 12 males and 10 females). No patients had a psychotic disease or endocrinopathy other than secondary hyperparathyroidism. Samples of venous blood were collected from the subjects after an overnight fast at the time of lumbar puncture for CSF sampling. C-terminal-specific RIA for measurement of the plasma and CSF concentrations of C-PTH was carried out using a commercially available RIA kit (Eiken Laboratory Inc., Tokyo, Japan).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Purification and properties of a specific primase-stimulating factor of bovine thymus.

The DNA replicase activity of the complex between bovine thymus DNA polymerase alpha and RNA primase was markedly decreased after the purification by ssDNA-cellulose column chromatography. In an attempt to restore the activity by supplementing some fractions eliminated from the purified enzyme, we found that a fraction eluted from the column by increasing salt concentration and 30% ammonium sulfate precipitates of the phosphocellulose-step enzyme possessed a high ability to restore the replicase activity. Thus, the factors were purified to near homogeneity from the two sources and the properties were examined. Both factors were heat-labile and trypsin-sensitive, possessed a native molecular mass of approximately 150-200 kDa as judged by Sephacryl S-200 column chromatography, and were composed of two polypeptides of 146 kDa and 47 kDa on SDS/polyacrylamide gel electrophoresis, indicating that they were an identical protein. The factor, which did not show any DNA polymerase or primase activities by itself, stimulated approximately 20-fold the replicase activity of purified DNA-polymerase-alpha-primase at a very low concentration (10 ng/50 microliter). The factor did not affect the deoxyribonucleotide polymerizing activity of the enzyme complex at all, but specifically stimulated the primase activity only. Thus, we designated the factor as primase-stimulating factor. Although varying the template concentration did not significantly affect the mode of stimulation, increasing the concentration of substrate for primer synthesis (ATP) markedly decreased the extent of stimulation. Thus, the stimulating factor seems to decrease the substrate concentration required for the primase reaction as well as increasing threefold the maximum activity attained by varying the substrate concentration. So far, no ATPase activity has been detected in the factor.

Animals↗
PubMed1988

1,25-Dihydroxyvitamin D3 binds specifically to rat vascular smooth muscle cells and stimulates their proliferation in vitro.

Cultured vascular smooth muscle cells (VSMC) derived from rat aorta were found to contain a specific receptor for 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]. Its Kd (5.0 x 10(-11) M) and capacity (22.9 fmol/mg of cytosol protein) for 1,25-(OH)2D3, its sedimentation coefficient on a sucrose density gradient (3.2 S), its relative affinities for various vitamin D3 metabolites [1,25-(OH)2D3 greater than 25-hydroxyvitamin D3 greater than 24,25-dihydroxyvitamin D3 greater than vitamin D3] and its affinity for DNA-cellulose were similar to those reported for the 1,25-(OH)2D3 receptor in other tissues. 1,25-(OH)2D3 at concentrations of more than 10(-10) M caused dose-dependent enhancement of the proliferation of VSMC in DMEM with 10% FCS. 25-Hydroxyvitamin D3 stimulated the proliferation of VSMC only at its highest concentration tested (10(-6) M). These data show that 1,25-(OH)2D3 stimulates the proliferation of VSMC after its binding to a cytoplasmic receptor of the cells in vitro, and support the possibility that VSMC are target cells of the hormone.

Animals↗
PubMed1988

Effect of estrogens on renal responsiveness to parathyroid hormone in elderly female subjects.

The effect of estrogens on the renal responsiveness to parathyroid hormone (PTH) was examined by PTH loading tests with synthetic human-PTH (1-34) in 8 normal elderly females (mean +/- SD age, 81.0 +/- 7.1 yr) before and after administration of estrogen (Premarin 1.25 mg/day for 4 weeks). Basal urinary adenosine cyclic 3', 5'-monophosphate (cAMP) excretion showed a tendency to increase after estrogen administration (5.47 +/- 1.68 vs 6.60 +/- 2.67 nmol/100 ml GFR) and the theoretical renal phosphorous threshold showed a tendency to decrease from 3.22 +/- 0.98 to 2.73 +/- 0.56 mg/dl. The blood ionized calcium concentration did not change after estrogen administration (4.44 +/- 0.16 vs 4.32 +/- 0.20 mg/dl) and serum phosphorous (P) decreased significantly (3.65 +/- 0.47 vs 3.01 +/- 0.42 mg/dl, p less than 0.05). There was no increase in mean serum immunoreactive PTH (0.34 +/- 0.10 vs 0.34 +/- 0.05 ngeq/ml). The urinary excretions of cAMP in response to PTH loading [100 U of human-PTH (1-34), intravenously] significantly (p less than 0.05) increased (94.8 +/- 57.0 vs 196.7 +/- 118.3 nmol/100 ml GFR/h) after estrogen administration. Moreover the changes in urinary excretion of cAMP (r = 0.698, p less than 0.01) and P (r = 0.555, p less than 0.05) induced by the PTH loading were positively correlated with serum estradiol in elderly females, assessed as groups before and after estrogen administration. These results suggest that estrogens may enhance the renal responsiveness to exogenous PTH administration.

Adult↗
PubMed1988

A patient with hypogonadotropic hypogonadism successfully treated by long-term pulsatile administration of luteinizing hormone-releasing hormone.

A male patient with hypogonadotropic hypogonadism has been treated by pulsatile administration lf luteinizing hormone-releasing hormone (LHRH) (20-25 micrograms, every 2 hours, sc) for 4 years 6 months. His plasma testosterone (T) concentration began to increase after 4 weeks of treatment and reached the normal range in week 5. He showed complete secondary sexual development after 1 year of treatment. His sperm count was normalized after 1 year of treatment. He was married after 29 months of therapy, and has a healthy male child. Blood type tests showed his paternity of the child. During the long duration of pulsatile LHRH therapy, his gonadotropin secretion has been stimulated by LHRH and his T level has been maintained with no observable side effects. There are no other reports of patients treated by pulsatile LHRH injection for such a long duration, but finding in this patient indicated that long-term pulsatile LHRH therapy is a useful and safe method for treatment of hypothalamic hypogonadotropic hypogonadism.

Adult↗