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T Hosono

Publications and source records attributed to T Hosono.

At least 37 records · Page 2Linked to original sources
PubMed2001

Invasive pulmonary aspergillosis in a puerperant with drug-induced agranulocytosis.

Invasive pulmonary aspergillosis (IPA) is an acute infection of Aspergillus species to the lungs. It generally occurs in immunocompromised hosts, especially with neutropenia. We report a 30-year-old puerperant, who developed IPA from agranulocytosis. She had been treated for threatened labor with ritodrine and cefepime, one of which induced agranulocytosis. After vaginal delivery of twins, pneumonia emerged in the right lower lobe. She was diagnosed to have IPA according to the halo sign on computed tomography (CT) and positive circulating antibody against Aspergillus, and was treated successfully with oral itraconazole followed by surgical resection. It is important to note that IPA might arise in otherwise immunocompetent hosts when neutropenia is long-standing.

Adult↗
PubMed2001

Hypothalamic region facilitating shivering in rats.

Although the posterior part of the hypothalamus has long been considered important for thermoregulatory shivering, it is unknown whether the neurons there or the passing fibers are implicated in the response. Exposure of urethane-anesthetized rats to cold (15-21 degrees C) elicits shivering. An injection of muscimol (0.5 mM), a GABA(A) receptor agonist, into the medial part of the hypothalamus, including the dorsomedial and posterior nuclei, suppressed the cold-induced shivering. This result suggests that neurons having an excitatory effect on shivering are in this region of the hypothalamus.

Animals↗
PubMed2000

Long-term replication of Epstein-Barr virus-derived episomal vectors in the rodent cells.

Plasmids containing the origin of replication, oriP, of the Epstein-Barr virus (EBV) and EBV nuclear antigen-1 genes replicate extrachromosomally in primate cells. However, these plasmids have been believed not to replicate in rodent cells. We demonstrate here that these plasmids can replicate in some types of rodent cells over a long period. This result should offer not only the new insight into the mechanisms of species-specific replication of EBV, but also the possibility that an EBV-based vector can be used for gene transfer experiments in non-primate cells and an animal experiment regarding human gene therapy.

3T3 Cells↗
PubMed2000

Neuron-independent Ca(2+) signaling in glial cells of snail's brain.

To directly monitor the glial activity in the CNS of the pond snail, Lymnaea stagnalis, we optically measured the electrical responses in the cerebral ganglion and median lip nerve to electrical stimulation of the distal end of the median lip nerve. Using a voltage-sensitive dye, RH155, we detected a composite depolarizing response in the cerebral ganglion, which consisted of a fast transient depolarizing response corresponding to a compound action potential and a slow depolarizing response. The slow depolarizing response was observed more clearly in an isolated median lip nerve and also detected by extracellular recording. In the median lip nerve preparation, the slow depolarizing response was suppressed by an L-type Ca(2+) channel blocker, nifedipine, and was resistant to tetrodotoxin and Na(+)-free conditions. Together with the fact that a delay from the compound action potential to the slow depolarizing response was not constant, these results suggested that the slow depolarizing response was not a postsynaptic response. Because the signals of the action potentials appeared on the saturated slow depolarizing responses during repetitive stimulation, the slow depolarizing response was suggested to originate from glial cells. The contribution of the L-type Ca(2+) current to the slow depolarizing response was confirmed by optical recording in the presence of Ba(2+) and also supported by intracellular Ca(2+) measurement. Our results suggested that electrical stimulation directly triggers glial Ca(2+) entry through L-type Ca(2+) channels, providing evidence for the generation of glial depolarization independent of neuronal activity in invertebrates.

Animals↗
PubMed2000

Effects of food deprivation on daily changes in body temperature and behavioral thermoregulation in rats.

Homeothermic animals regulate body temperature (T(b)) by using both autonomic and behavioral mechanisms. In the latter process, animals seek out cooler or warmer places when they are exposed to excessively hot or cold environments. Thermoregulation is affected by the state of energy reserves in the body. In the present study, we examine the effects of 4-day food deprivation on circadian changes in T(b) and on cold-escape and heat-escape behaviors in rats. Continuous measurement of T(b) during food deprivation indicated that the peak T(b) amplitude was not different from baseline values, but the trough amplitude continuously decreased after the onset of food deprivation. Cold-escape behavior was facilitated by food deprivation, whereas heat-escape behavior was unchanged. After the termination of food deprivation, the lowered T(b) returned to normal on the first day. However, cold-escape behavior was still facilitated on the third day after food reintroduction. Autonomic and behavioral thermoregulatory effectors are modulated in the face of food shortage so as to maintain optimal performance during the active period, whereas increasing energy conservation occurs during the quiescent phase.

Animals↗
PubMed2000

[PL granule-induced pneumonia requiring mechanical ventilation].

PL granule is one of the most common forms of composite medicine for colds in Japan, including acetaminophen. We report a case of PL granule-induced pneumonia that required mechanical ventilation. A 72-year old man who had been prescribed amiodarone for more than one year before for arrhythmogenic right ventricular dystrophy, repeatedly took PL granules at one-week intervals because of sneezing and fever. He then underwent acute respiratory failure. He needed mechanical ventilation for severe hypoxemia, but recovered with glucocorticoid pulse therapy. Because the blastoid transformation test using his peripheral blood lymphocytes was positive on stimulation with PL granules, but negative on amiodarone stimulation, he was diagnosed as having drug (PL granule)-induced pneumonia. Only one case of PL granule-induced pneumonia and seven of acetaminophen-induced pneumonia have been reported. None of these patients needed mechanical ventilation. PL granule-induced pneumonia should be treated cautiously because of possible acute exacerbation.

Aged↗
PubMed2000

Pulmonary nocardiosis during immunosuppressive therapy for idiopathic pulmonary fibrosis.

Nocardiosis is a subacute or chronic suppurative infection caused by Nocardia species. Although it is more common in immunocompromised hosts, idiopathic pulmonary fibrosis (IPF) has not been recognized as a predisposing factor for nocardial infection. We report a case of IPF, in which pulmonary nocardiosis developed during treatment with prednisolone and cyclophosphamide. The risk of pulmonary nocardiosis may be increased in cases of IPF on immunosuppressive therapy. Since IPF often accompanies lung carcinoma, it is important to correctly differentiate nocardiosis from carcinoma.

Aged↗
PubMed1999

Structure and distribution of rat menin mRNA.

Menin is a protein product of a tumor suppressor gene MEN1, mutations of which are responsible for multiple endocrine neoplasia type 1, an autosomal dominant familial cancer syndrome. We isolated rat menin cDNA clones from a fetal rat brain cDNA library. We also determined the nucleotide sequence of the protein coding region of mouse menin cDNA, which was partly registered in the expressed sequence tag (EST) database. Deduced amino acid sequences of rat and mouse menin are highly homologous to human menin. All of the previously reported disease-associated missense mutations and single amino acid deletions were observed at the residues that are conserved among these three species. Rat MEN1 transcripts were detected not only in the endocrine tissues but also in the tissues of the nervous, digestive, reproductive and immune systems. The MEN1 transcripts were abundantly expressed in the developing rat brain on day 14-18 of gestation. Immunoblotting and immunocytochemical analysis of the COS-7 cells transfected with a rat menin-expression vector revealed that the translated product has a molecular mass of approximately 70 kDa, and is localized mainly in the nucleus. These findings are consistent with those reported on human menin.

Amino Acid Sequence↗
PubMed1999

An isoform of Nurr1 functions as a negative inhibitor of the NGFI-B family signaling.

NGFI-B, Nurr1 and NOR-1 constitute a distinct subfamily within the nuclear receptor superfamily. To clarify the transcriptional regulation by the NGFI-B family, we searched for other components that can bind to the NBRE response element, a known target sequence for these transcription factors. By low stringency hybridization using the DNA binding domain of NOR-1 as a probe, a C-terminal truncated Nurr1 isoform, named Nurr2, was isolated from a mouse MC3T3-E1 cell cDNA library. Nurr2 had a novel cryptic exon located upstream in the Nurr1 promoter region, and was generated by alternative splicing at exons 1, 2 and 6. The C-terminal region was encoded by frame-shifted exon 6, and so Nurr2 lacked the C-terminal sequences corresponding to the putative ligand binding domain or dimerization domain. Quantitative reverse transcriptase-PCR experiments confirmed the presence of the Nurr2 isoform in mouse, rat and human. It was, like Nurr1, highly expressed in the pituitary and the cerebral cortex. Nurr2 and Nurr1 were also concomitantly induced by forskolin in NIH3T3 cells. Functional analysis using a reporter gene, containing NBRE response elements, indicated that while the isoform was inactive by itself, it could inhibit transactivation by the members of the NGFI-B family. These results indicate that the C-terminal truncated isoform, Nurr2, may act as a negative regulator of the NGFI-B family signaling.

3T3 Cells↗
PubMed1999

Neuronal actions of oxytocin on the subfornical organ of male rats.

The aim of this study was to investigate effects of oxytocin (OT) on electrical neuronal activities in rat subfornical organ (SFO) and compare its action with the well-described excitatory effects of blood-borne angiotensin II (ANG II) on the same SFO neurons. With the use of extracellular recordings from spontaneously active neurons in slice preparations of the SFO of male rats, 11.7% of tested neurons (n = 206) were excited and 9.7% were inhibited by superfusion with 10(-6) M OT. Both excitatory and inhibitory effects of OT were dose dependent with similar threshold concentrations and were blocked by a specific OT-receptor antagonist but not by a vasopressin receptor antagonist. Blocking synaptic transmission with low calcium medium suppressed only inhibitory effects of OT. All but one of the OT-sensitive neurons were also excited by superfusion with ANG II at a concentration much lower than required for OT, suggesting that synaptically released OT rather than blood-borne OT alters the activity of SFO neurons in vivo. The results support the hypothesis that neurally released OT may modulate SFO-mediated functions by acting on OT-sensitive neurons.

Angiotensin II↗
PubMed1999

HPLC profile analysis of hepatoprotective oleanene-glucuronides in Puerariae Flos.

In order to confirm the constitution of hepatoprotective oleanene glucuronide (OG), HPLC profile analyses of the total OG fractions of both Puerariae Thomsonii Flos (the flowers of Pueraria thomsonii) and Puerariae Lobatae Flos (the flowers of P. lobata) were performed. No remarkable difference in the HPLC profiles with respect to OGs in the flowers was shown, in contrast to those of the roots. By repeated chromatography of the total OG fraction of Puerariae Thomsonii Flos, soyasaponin I (1), kaikasaponin III (2) and kakkasaponin I (3), which had been already isolated from Puerariae Lobatae Flos, were obtained. The hepatoprotective activity of 2 towards immunologically induced liver injury was significantly more effective than that of 1. This information supported previously obtained structure-hepatoprotective relationship data which was measured on another model. The structure-activity relationship information which suggested that the hydroxymethyl group of the galactosyl unit would enhance the hepatoprotective activity was also substantiated.

Animals↗
PubMed1998

Efferent projection from the preoptic area for the control of non-shivering thermogenesis in rats.

1. To investigate the characteristics of efferent projections from the preoptic area for the control of non-shivering thermogenesis, we tested the effects of thermal or chemical stimulation, and transections of the preoptic area on the activity of interscapular brown adipose tissue in cold-acclimated and non-acclimated anaesthetized rats. 2. Electrical stimulation of the ventromedial hypothalamic nucleus (VMH) elicited non-shivering thermogenesis in the brown adipose tissue (BAT); warming the preoptic area to 41.5 C completely suppressed the thermogenic response. 3. Injections of d, l-homocysteic acid (DLH; 0.5 mM, 0.3 microliter) into the preoptic area also significantly attenuated BAT thermogenesis, whereas injections of control vehicle had no effect. 4. Transections of the whole hypothalamus in the coronal plane at the level of the paraventricular nucleus induced rapid and large rises in BAT and rectal temperatures. This response was not blocked by pretreatment with indomethacin. The high rectal and BAT temperatures were sustained more than 1 h, till the end of the experiment. Bilateral knife cuts that included the medial forebrain bundle but not the paraventricular nuclei elicited similar rises in BAT and rectal temperatures. Medial knife cuts had no effect. 5. These results suggest that warm-sensitive neurones in the preoptic area contribute a larger efferent signal for non-shivering thermogenesis than do cold-sensitive neurones, and that the preoptic area contributes a tonic inhibitory input to loci involved with non-shivering thermogenesis. This efferent inhibitory signal passes via lateral, but not medial, hypothalamic pathways.

Acclimatization↗
PubMed1998

New apparatus for studying behavioral thermoregulation in rats.

The operant system described here contains a box that can be convectively heated or cooled. A rat moves freely in the box. Its location is monitored photoelectrically while its deep body temperature is monitored by a telemetry system. In heat-escape experiments, hot air (40 degrees C) flows through the box. When the rat enters a reward zone the air source is switched and cold air (0 degrees C) flows through the box for a given period (30 s). Conversely, in cold-escape experiments cold air flows through the box and when the rat enters the reward zone the air source is switched to a warm one. Experiments show that rats quickly learn to stay near the reward zone and move in and out of it periodically. This system is based on behavior more natural than the frequently used lever-pressing response, and has many advantages for use in studies involving behavioral thermoregulation.

Animals↗
PubMed1998

The NGFI-B subfamily of the nuclear receptor superfamily (review).

NGFI-B, Nurr1 and NOR-1 have structural features of ligand-activated transcriptional regulators and constitute the NGFI-B subfamily within the nuclear receptor superfamily. Since specific ligands for these molecules have not yet been identified, they are often called orphan nuclear receptors. Genes of the NGFI-B subfamily are classified as immediate-early genes that are induced rapidly but transiently by a variety of stimuli. Evidence accumulated over the past decade suggests this subfamily is involved in important physiological processes and cancer development. In this communication, we summarize and discuss their structural features, gene expression, physiological roles and oncological significance.

Animals↗
PubMed1997

Effect of midbrain stimulations on thermoregulatory vasomotor responses in rats.

1. Efferent projections eliciting vasodilatation when the preoptic area is warmed were investigated by monitoring tail vasomotor responses of ketamine-anaesthetized rats when brain areas were stimulated electrically (0.2 mA, 200 microseconds, 30 Hz) or with the excitatory amino acid D,L-homocysteic acid (1 mM, 0.3 microliter). 2. Both stimulations elicited vasodilatation when applied within a region extending from the most caudal part of the lateral hypothalamus to the ventrolateral periaqueductal grey matter (PAG) and the reticular formation ventrolateral to the PAG. 3. Vasodilatation elicited by preoptic warming was suppressed when either stimulation was applied within the rostral part of the ventral tegmental area (VTA). 4. Sustained vasodilatation was elicited by knife cuts caudal to the VTA, and vasodilatation elicited by preoptic warming was suppressed by cuts either rostral to the VTA or in the region including the PAG and the reticular formation ventrolateral to it. 5. These results, together with the results of earlier physiological and histological studies, suggest that warm-sensitive neurones in the preoptic area send excitatory signals to vasodilatative neurones in the caudal part of the lateral hypothalamus, ventrolateral PAG and reticular formation, and send inhibitory signals to vasoconstrictive neurones in the rostral part of the VTA.

Animals↗
PubMed1997

Effect of gonadotropin releasing hormone on thermoregulatory vasomotor activity in ovariectomized female rats.

To investigate the effect of gonadotropin releasing hormone (GnRH) on thermoregulatory skin vasomotion, we injected GnRH into various brain regions in both anesthetized and unanesthetized ovariectomized female rats. Local warming of preoptic area (PO) elicited skin vasodilation in anesthetized rats. Injection of 2 microg GnRH into the septal area lowered the threshold hypothalamic temperature for skin vasodilation at least for 2 h. Similar injections of 2 microg GnRH into the lateral ventricle (LV) and PO were ineffective. Although this vasodilative effect was also obtained after the injection of 20 ng GnRH into the septal area, injections of 2 ng GnRH were without effect. Not only injections of 20 ng Antide, a potent GnRH antagonist, but also injections of the mixed solution of 20 ng GnRH and 20 ng Antide were also without effect. In unanesthetized and unrestrained rats at an ambient temperature of 17 degrees C, injections of 20 ng GnRH into the septal area elicited tail vasodilation lasting for 30 minutes, whereas vehicle injections were ineffective. Injections of 20 ng GnRH into LV and PO were also ineffective. These results indicate that GnRH can elicit thermoregulatory skin vasomotion by acting on GnRH receptors in the septal area. This thermoregulatory vasodilative effect of GnRH might be possibly related to the etiology of climacteric hot flush.

Animals↗