The effects of ambient and hypothalamic temperatures on the hyperthermic responses to prostaglandins E1 and E2

Summary The effects of ambient and hypothalamic temperatures were studied on the hyperthermic responses to prostaglandins E₁ and E₂ (PGE₁ and PGE₂) injected intraventricularly in the unanesthetized rabbit. Hyperthermic responses to PGE₁ observed at different thermal environments were approximately equal in magnitude and time course. However, the prevailing ambient temperature influenced the thermoregulatory mechanisms by which the hyperthermia was achieved. In a hot environment, PGE₁-hyperthermia was brought about by suppression of heat loss mechanism with little change in heat production. During cold exposure body temperature was raised mainly by an increase in heat production without a significant change in heat loss. PGEs-hyperthermias were attenuated by warming and enhanced by cooling the anterior hypothalamus. These changes in the hyperthermic responses to PGE₁ and PGE₂ are in contrast to those obtained with intraventricular injection of noradrenaline at different ambient temperatures and during hypothalamic heating and cooling. It is therefore unlikely that noradrenaline is involved in the hyperthermic responses to PGEs. On the other hand, the results support the view that prostaglandins may be mediators of pyrogen-induced fever.     

Aromatase as a cellular marker of testosterone action in the preoptic area.

We recently showed, using a new immunocytochemical technique, that aromatase-immunoreactive neurons are a specific marker for the sexually dimorphic medial preoptic nucleus (POM) in quail and that the number of these immunoreactive cells is markedly increased by a systemic treatment with testosterone (T). Since the POM is a key site for the activation of copulatory behavior by T and this androgen must be converted into estrogen by local aromatization within the POM before it can exert its behavioral effects, we used aromatase immunocytochemistry to map, at a cellular level of resolution, the areas that are destroyed by electrolytic lesions or that are stimulated by the stereotaxic implantation of T in the preoptic area (POA). These measures of the cellular action of T in the preoptic area were then correlated with the behavior of the animals to identify the parts of the POA that are critical in the activation of behavior. The electrolytic lesions of the POA disrupted the activation of male sexual behavior by T only if they destroyed a significant part of the POM. All lesions reduced the volume of the dimorphic nucleus and the absolute number of its aromatase-immunoreactive neurons, but the density of these cells in the remaining POM was not affected, suggesting that the volume change in the nucleus reflected a centripetal displacement of its boundaries rather than an overall shrinkage of the structure. Stereotaxic T implants in or close to POM activated male copulatory behavior and increased the volume of the POM and the number of its aromatase-immunoreactive cells. These neuroanatomical effects were more prominent on the side of the implant, but they were also detected on the contralateral side. Correlative analyses suggested that a part of the POM just rostral to the anterior commissure is critical for the activation of copulatory behavior. The best correlations between the behavioral deficits induced by electrolytic lesions and the size of the lesions were indeed observed in this area. In addition, high correlations were also observed between the behavior activated by T implants and the POM size or number of aromatase-immunoreactive cells that were induced by T in this area. Aromatase immunocytochemistry therefore appears as a useful tool to map the brain areas in which T action is presumably critical for the activation of male sexual behavior. It has allowed us to identify in the present studies a small part of the sexually dimorphic POM that is closely associated with behavior.(ABSTRACT TRUNCATED AT 400 WORDS)     

Establishment of dental epithelial cell line (HAT-7) and the cell differentiation dependent on Notch signaling pathway

Rat incisors grow continuously throughout life. Producing a variety of dental epithelial cells is performed by stem cells located in the cervical loop of the incisor apex. To study the mechanisms for cell differentiation, we established a dental epithelial cell line (HAT-7) originating from a cervical loop epithelium of a rat incisor. Immunochemical studies showed that HAT-7 produced the cells expressing amelogenin, ameloblastin, or alkaline phosphatase (ALP). To illustrate a role of Notch signaling in the determinant of the cell fate, we examined expression patterns of Notch1 and Jagged1 in HAT-7 density dependently. At lower cell density, Notch1- or Jagged1-expressing cells were not seen. However, when they were fully confluent, cells began to express Notch1 or Jagged1 strongly. Some ALP-positive cells were almost consistent with Notch1-expressing cells but not Jagged1-expressing cells. These results suggested that the determinant of direction of differentiation was associated with Notch signaling pathway.     

Minimally invasive therapy under image guidance--emphasizing MRI-guided cryotherapy

Cryotherapy may provide a method for the focal destruction of cancerous tissue while preserving most of the surrounding normal tissue. The mechanisms of tissue injury in cryotherapy are 1) intracellular ice formation, 2) dehydration of cells, and 3) stagnation of microcirculation. MR images were superior to CT and ultrasound in monitoring interstitial cryotherapy, because the very short T2 relaxation time of ice affords excellent contrast between the ice and surrounding tissue, allowing an accurate depiction of the entire extent of the iceball. MR imaging demonstrates the iceball as sharply marginated regions of signal loss that expanded and engulfed the renal and hepatic masses with clear contrast between the iceball and surrounding tissue. Recently, a fast Joule-Thomson cryocycling device for MR-compatible cryotherapy application was developed and clinical trials under MRI-guided monitoring were performed in several sites of the body. In our series, cryotherapy was performed in 14 cases of renal tumor and 4 cases of hepatic malignancy under the guidance of a horizontal open MR system. Fourteen of the 18 cases were discharged a day after cryotherapy. One of the residual tumors at the margin of a renal cancer required re-cryoablation. All cryoablated tumors resolved and there were no serious complications and no clinically significant changes-during the follow-up study.     

De novo interstitial deletion of 1p (pter----p34.1::p32.3----qter).

We report a case of a 9 month old girl with a de novo interstitial deletion of 1p, karyotype 46,XX, del(1)(pter----p34.1::p32.3----qter). She had dysmorphic features including upward slanting palpebral fissures, a bulbous nose, a long philtrum, low set and malformed ears, a short neck, hypoplastic nails on both index fingers, widened interdigital spaces between the toes, dilated lateral ventricles, right hydronephrosis, a dilated right ureter, mental and motor developmental delay, and generalised hypotonia.     

Acanthamoeba-specific human T-cell clones isolated from healthy individuals

T-cell responses to pathogenic free-living amoebae,Acanthamoeba sp., were analyzed in healthy Japanese individuals. Of 20 healthy subjects, 10 (50%) showed significant proliferative responses of peripheral blood mononuclear cells to the soluble amoebic antigens in vitro. The antigens used were not mitogenic, and no evidence of amoebic superantigens was available. We established human T-cell clones reactive toAcanthamoeba, all of which were CD3- and CD4-positive, CD8-negative, and TCR--positive. We isolated two strains ofAcanthamoeba from two patients, one from a patient with meningoencephalitis (CSF strain) and the other from a patient with keratitis (K strain). Of 13 clones, 11 were reactive to the K-strain as well as to the CSF-strain antigen under human leukocyte antigen (HLA)-DR restriction, whereas the other two were specific for the K-strain antigen. All but one clone tested showed TH1-equivalent functions because these cells produced interferon (IFN)- in response to the amoebic antigen but produced no detectable level of interleukin 4 (IL-4). These results suggest that immunocompetent hosts might have acquired protective immunity mediated byAcanthamoeba-specific T-cells during natural sensitization.     

Ras homolog gene family H (RhoH) deficiency induces psoriasis-like chronic dermatitis by promoting TH17 cell polarization

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