Laparoscope-assisted Hassab's operation for esophagogastric varices after living donor liver transplantation: a case report.

This is the first successful report of a laparoscope-assisted Hassab's operation for esophagogastric varices after living donor liver transplantation (LDLT). A 35-year-old man underwent LDLT using a right lobe graft as an aid for primary sclerosing cholangitis (PSC) in 2005. Follow-up endoscopic and computed tomography (CT) examinations showed esophagogastric varices with splenomegaly in 2009 that increased (esophageal varices [EV]: locus superior [Ls], moderator enlarged, beady varices [F2], medium in number and intermediate between localized and circumferential red color signs [RC2]; gastric varices [GV]: extension from the cardiac orifice to the fornix [Lg-cf], moderator enlarged, beady varices [F2], absent red color signs [RC0]). A portal venous flow to the esophagogastric varices through a large left gastric vein was also confirmed. Preoperative Child-Pugh was grade B and score was 9. Because these esophagogastric varices had a high risk of variceal bleeding, we proceeded with a laparoscope-assisted Hassab's operation. Operative time was 464 minutes. Blood loss was 1660 mL. A graft liver biopsy was also performed and recurrence of PSC was confirmed histologically. It was suggested that portal hypertension and esophagogastric varices were caused by recurrence of PSC. Postoperative complications were massive ascites and enteritis. Both of them were treated successfully. This patient was discharged on postoperative day 43. Follow-up endoscopic study showed improvement in the esophagogastric varices (esophageal varices [EV]: locus superior [Ls], no varicose appearance [F0], absent red color signs [RC0], gastric varices [GV]: adjacent to the cardiac orifice [Lg-c], no varicose appearance [F0], absent red color signs [RC0]) at 6 months after the operation. We also confirmed the improvement of esophagogastric varices by serial examinations of CT.

Rapid induction of the growth hormone gene transcription by glucocorticoids in vitro: possible involvement of membrane glucocorticoid receptors and phosphatidylinositol 3-kinase activation.

The regulation of transcription of the growth hormone (GH) gene by glucocorticoids was studied in MtT/S cells, a cell line derived from an oestrogen-induced mammotrophic tumour in the rat, and in the primary culture of the anterior pituitary gland of adult mice. The levels of the GH heteronuclear RNA (GH hnRNA), which are mainly determined by the transcription rate, increased by 25-fold during 24 h in response to dexamethasone (DEX; 1 µM) in MtT/S cells that were cultured in the medium containing charcoal-stripped serum for 7 days. The stimulatory effect of DEX on the GH hnRNA levels was detectable as early as 30 min. This rapid effect of DEX did not require on-going protein synthesis, whereas it was considered that DEX requires the presence of unknown cellular proteins produced independently of DEX stimulation. By contrast, on-going protein synthesis was required for DEX action when incubated for 6 h, as has been observed in the previous studies. The specific inhibitor of glucocorticoid receptor, RU486, inhibited both rapid (30 min) and delayed (6 h) the effects of glucocorticoids on GH hnRNA levels. Membrane impermeable glucocorticoid, corticosterone-bovine serum albumin conjugate (CSBSA), was found to have effects similar to those of DEX and free corticosterone (CS), suggesting that glucocorticoids regulate GH gene transcription at least in part through the membrane bound receptors. From pharmacological studies, it was suggested that phosphatidylinositol 3-kinase (PI3K) activation is involved in the rapid effects but not in the delayed effects of glucocorticoids. This also suggests that the delayed effects of glucocorticoids depend on mechanisms other than the activation of PI3-kinase. Finally, both rapid and delayed effects of CS and CSBSA were observed not only in MtT/S cells, but also in the mouse pituitary cells in primary culture. Therefore, it is possible that the membrane initiated action of glucocorticoids is involved in the regulation of GH transcription in normal pituitary cells, as well as in pituitary tumour cells.

Epidermal growth factor-activated extracellular signal-regulated kinase suppresses growth hormone expression and stimulates proliferation in MtT/ E cells.

The mechanism for the inhibition of growth hormone (GH) expression by the epidermal growth factor (EGF) was examined in two clonal cell lines, MtT/E and MtT/S. The former has a negligible basal level of GH, whereas the latter has a high basal GH. The treatment of MtT/E cells with retinoic acid resulted in a significant increase in GH mRNA and subsequently GH. This stimulatory response to retinoic acid was strongly suppressed by EGF. This suppression was associated with an increase in the phosphorylation of extracellular signal-regulated kinase 1 and 2 (Erk1/2). The MEK [mitogen-activated protein kinase (MAPK) kinases that activate ERK1 and ERK2] inhibitor, PD98059, clearly inhibited the phosphorylation of Erk1/2 and restored the stimulatory effects of retinoic acid. These results suggest that the inhibitory effects of EGF on GH expression are mediated by MAPK activation in these cells. By contrast to the GH-producing clones examined previously, EGF showed a marked stimulation of proliferation of the MtT/E cells through a mechanism dependent on MAPK activation. On the other hand, the inhibitory effect of EGF on GH expression was less pronounced and the stimulation of cellular proliferation was not seen in MtT/S cells, even though it induced Erk-phosphorylation similar to that seen in MtT/E. The distinct difference in the response to EGF between these two GH cell lines appears to be attributed to differences in the function of MAPK cascade in each cell line. This may reflect the developmental stage of the cells from which MtT/E and MtT/S are derived.

The ontogenic expressions of multiple vesicular glutamate transporters during postnatal development of rat pineal gland.

The pineal gland expresses vesicular glutamate transporters 1 and 2 (VGLUT1 and VGLUT2), which are thought to transport glutamate into synaptic-like microvesicles in the pinealocytes. Recently, we reported that the rat pineal gland also expresses VGLUT1v which is a novel variant of VGLUT1 during the perinatal period. To explore the biological significance of these VGLUT expressions in pineal development, we studied the ontogeny of VGLUT in this gland by in situ hybridization, immunohistochemistry and quantitative reverse transcription-polymerase chain reaction (RT-PCR) using rats. Histological analysis revealed that intensities of VGLUT1 hybridization signal and immunostaining drastically increase by postnatal day (P) 7, whereas VGLUT2 expression exhibits high levels of mRNA and protein at birth and decreases gradually from P7 onward. Quantitative RT-PCR analysis supported these histological observations, showing that expressions of VGLUT1 and VGLUT2 exhibit opposite patterns to each other. Coinciding with VGLUT1-upregulation, RT-PCR data showed that expressions of dynamin 1 and endophilin 1, which are factors predictably involved in the endocytotic recovery of VGLUT1-associated vesicle, are also increased by P7. Quantitative RT-PCR analysis of VGLUT1v demonstrated that its mRNA expression is upregulated by P7, kept at the same level until P14, and apparently decreased at P21, suggesting its functional property required for a certain developmental event. Moreover, a comparison of mRNA expressions at daytime and nighttime revealed that neither VGLUT1 nor VGLUT1v shows any difference in both P7 and P21 glands, whereas VGLUT2 is significantly lower at daytime than at nighttime at P21 but not P7, the time point at which the melatonin rhythm is not yet generated. The present study shows that expressions of these VGLUT types are differentially regulated during postnatal pineal development, each presumably participating in physiologically distinct glutamatergic functions.

Region-specific expression and hormonal regulation of the first exon variants of rat prolactin receptor mRNA in rat brain and anterior pituitary gland.

Recent studies have revealed the occurrence of five first exon variants of the rat prolactin receptor mRNA, suggesting that multiple promoters direct prolactin receptor transcription in response to different regulatory factors. In the present study, regional expression of these first exon variants, as well as two prolactin receptor subtypes generated by alternative splicing, was examined in the brains and anterior pituitary glands of female rats. Expression of the long-form was detected in the choroid plexus, hypothalamus, hippocampus, cerebral cortex and anterior pituitary gland, whereas the short form was detected only in the choroid plexus. E1-3 mRNA, a first exon variant, was detected in the choroid plexus, hypothalamus, and anterior pituitary gland, whereas E1-4 was detected only in the choroid plexus. Other variants were not detectable by the polymerase chain reaction protocol employed in this study. Ovariectomy increased the short form in the choroid plexus and the E1-3 expression in the choroid plexus and pituitary gland, but changes in the long-form and E1-4 expression were minimal. Replacement of oestrogens and prolactin suggest that oestrogens down-regulate E1-3 expression in the choroid plexus and pituitary gland, and that the negative effect of oestrogen is mediated by prolactin in the pituitary gland. The present results revealed the region-specific promoter usage in prolactin receptor mRNA transcription, as well as the involvement of oestrogens in the regulation of E1-3 mRNA expression in the brain and pituitary gland.

Dependence of fragmentation behavior of colloidal aggregates on their fractal structure.

The fragmentation dynamics of aggregate of non-Brownian particles in shear flow is investigated numerically. The breakup behaviors of aggregates having the same connectivity but the different space-filling properties are examined. The Lagrangian particle simulation in a linear flow field is performed. The effect of surrounding fluid on the motion of multiple particles is estimated by Stokesian dynamics approach. The inter-particle force is calculated from the retarded van der Waals potential based on the Lifshitz theory. The results obtained in this work indicate that the fragmentation behavior of colloidal aggregates depends on their fractal structure. However, if the resultant aggregate size is smaller than the critical one, the fragmentation behavior shows the universality regardless of their original structure. Furthermore, the restructuring of aggregate in shear flow and its effect on the fragmentation process are also discussed.

Cigarette nicotine yields and nicotine intake among Japanese male workers.

OBJECTIVES: To analyse brand nicotine yield including "ultra low" brands (that is, cigarettes yielding less-than-or-equal 0.1 mg of nicotine by Federal Trade Commission (FTC) methods) in relation to nicotine intake (urinary nicotine, cotinine and trans-3'-hydroxycotinine) among 246 Japanese male smokers. DESIGN: Cross sectional study. SETTING: Two companies in Osaka, Japan. SUBJECTS: 130 Japanese male workers selected randomly during their annual regular health check up and 116 Japanese male volunteers taking part in a smoking cessation programme. MAIN OUTCOME MEASUREMENTS: Subjects answered a questionnaire about smoking habits. Following the interview, each participant was asked to smoke his own cigarette and, after extinguishing it, to blow expired air into an apparatus for measuring carbon monoxide concentration. Urine was also collected for the assays of nicotine metabolites. RESULTS: We found wide variation in urinary nicotine metabolite concentrations at any given nicotine yield. Based on one way analysis of variance (ANOVA), the urinary nicotine metabolite concentrations of ultra low yield cigarette smokers were significantly lower compared to smokers of high (p = 0.002) and medium yield cigarettes (p = 0.017). On the other hand, the estimated nicotine intake per ultra low yield cigarette smoked (0.59 mg) was much higher than the 0.1 mg indicated by machine. CONCLUSIONS: In this study of Japanese male smokers, actual levels of nicotine intake bore little relation to advertised nicotine yield levels. Our study reinforces the need to warn consumers of inappropriate advertisements of nicotine yields, especially low yield brands.

Effects of diethylstilbestrol on the cytogenesis of prolactin cells in the pars distalis of the pituitary gland of the mouse.

This study was carried out to examine the developmental stage when prolactin cells differentiate in mice and to examine the effects of diethylstilbestrol on the development of prolactin cells in the fetal and neonatal pituitary glands. A small number of immunoreactive prolactin cells appeared first on embryonic day 15 in control (injected with oil) pituitary glands, whereas they did not increase in number until postnatal day 2. In diethylstilbestrol-treated mice (5 mg/kg body weight, 24 h before killing), a small number of immunoreactive prolactin cells were detectable as early as embryonic day 14, but not on day 13. They increased in number on embryonic days 15 and 16, and decreased markedly on days 17 and 18, followed by a rapid increase after birth. This transient reduction in the response to diethylstilbestrol was partially restored by treatment with metyrapone, a specific inhibitor of corticosteroid production. These results suggest that in the mouse: (1) differentiation of prolactin cells occurs between embryonic days 13 and 14, (2) prolactin gene expression is suppressed in the nascent prolactin cells presumably due to the presence of high levels of estrogen-binding protein, alpha-fetoprotein, and (3) prolactin gene expression is also suppressed by elevation of circulating glucocorticoids during the perinatal period. The present results suggest that, in the mouse, at least a proportion of prolactin cells are not derived from growth hormone cells, because the diethylstilbestrol-induced prolactin cells appear earlier than growth hormone gene expression.

Heat moisture treatment of high amylose cornstarch increases its resistant starch content but not its physiologic effects in rats.

To examine whether the physiologic effects of high amylose cornstarch (HACS) are affected by gelatinization or heat moisture treatment, male rats were fed for 21 d a fiber-free purified diet containing 40 g/100 g gelatinized normal cornstarch (G-CS), HACS, gelatinized high amylose cornstarch (G-HACS) or heat moisture-treated HACS (HMCS). Dietary fiber (DF) content in G-HACS was 87% lower than that in HACS. The apparent starch and protein digestibilities were higher in the G-HACS group than in the HACS group. Fecal wet weight and fecal bile acid excretion were lower in the G-HACS group than in the HACS group. The cecal tissue weight, cecal surface area, cecal content weight and cecal pH were lower in the G-HACS group than in the HACS group. The cecal n-butyric acid and succinic acid concentrations were higher and lower, respectively, in the G-HACS group than in the HACS group. The plasma cholesterol and triacylglycerol concentrations did not differ between the G-HACS group and the HACS group. On the other hand, the DF content in HMCS was 330% higher than that in HACS, but the HMCS and HACS groups generally did not differ except in cecal surface area. Dietary starch did not affect fecal moisture, fecal neutral sterol (cholesterol + coprostanol) excretion, liver cholesterol level, total short-chain fatty acid (SCFA) concentration or apparent Ca, Fe, Mg and Zn absorptions. These results show that the heat moisture treatment of HACS for the most part does not alter its physiologic effects despite the greater DF content.

Differential localization and colocalization of two neuron-types of sodium-dependent inorganic phosphate cotransporters in rat forebrain.

We studied by immunohistochemistry the distribution of differentiation-associated sodium-dependent inorganic phosphate (Pi) cotransporter (DNPI) in the rat forebrain, in comparison with brain-specific cotransporter (BNPI). DNPI-staining was principally seen in axonal synaptic terminals which showed a widespread but discrete pattern of distribution different from that of the BNPI-staining. In the diencephalon, marked DNPI-staining was seen in the dorsal lateral geniculate, medial geniculate, ventral posterolateral, ventral posteromedial, anterior, and reticular thalamic nuclei without the colocalization with BNPI-staining. DNPI-staining showed a strong mosaical pattern and overlapped well the BNPI-staining in the medial habenular nucleus. DNPI-staining was moderate over the hypothalamus and notably localized in neurosecretory terminals containing corticotropin-releasing hormone in the median eminence. In contrast, the BNPI-staining was region-related and strong in the ventromedial and mammillary nuclei. In the telencephalon, laminar DNPI-staining was seen over the neocortex, corresponding to the thalamocortical termination, and also found in the retrosplenial cortex and the striatum, with the highest intensity in the accumbens nucleus shell. The present results suggest that DNPI serves as a dominant Pi transport system in synaptic terminals of diencephalic neurons including thalamocortical and thalamostriatal pathways as well as the hypothalamic neuroendocrine system in the rat forebrain.

Retinoic acids and thyroid hormone act synergistically with dexamethasone to increase growth hormone-releasing hormone receptor messenger ribonucleic acid expression.

The effects of all-trans-retinoic acid (RA), 9-cis-retinoic acid (9cRA), and thyroid hormone (T3) on GH-releasing hormone receptor (GHRH-R) messenger RNA (mRNA) expression were studied using ribonuclease protection assay in the fetal rat pituitary gland and in MtT/S cells, a clonal GH cell line derived from an estrogen-induced somatotropic tumor in the rat. Although RA (1 microM), 9cRA (1 microM), or T3 (1 nM) alone showed little effect on GHRH-R mRNA expression in the MtT/S cells, each of these substances was found to act synergistically with dexamethasone (DEX; 500 nM) to increase GHRH-R mRNA expression. The effects of RAs and T3 were dose dependent, with maximum effects observed at 1 microM and 1 nM, respectively. The maximum effect of RAs or T3 was not further augmented by the addition of T3 or RAs, respectively. No apparent differences were observed in this study between the actions of RA and 9cRA. The Northern analyses showed that MtT/S cells express retinoic acid receptor alpha2 mRNA and thyroid hormone receptor beta2 mRNA, and DEX did not affect the levels of these mRNAs. This suggests that the role of DEX in enabling RAs or T3 to up-regulate GHRH-R mRNA levels is not an induction of the expression of each specific receptor for RAs and T3. The similar enhancement of DEX induction of GHRH-R mRNA by RAs or T3 was also observed in the fetal rat pituitary gland in culture, suggesting that RA and/or T3 is involved in the mechanisms responsible for the developmentally regulated expression of GHRH-R mRNA.

[The relationship between stages and biochemical markers of smoking. Workplace-based cross-sectional and longitudinal studies].

In order to clarify smokers' characteristics by "Stages of Change" based on Prochaska's transtheoretical model, we conducted cross-sectional and logitudinal studies with biochemical markers of smoking and smoking habits. In a workplace-based sample of 277 male smokers, we examined cross-sectionally the relationships between stages and biochemical markers of smoking which include expired carbon monoxide concentrations and urinary nicotine metabolite concentrations, and smoking habits which include the number of cigarettes smoked per day, yields of cigarettes, inhalation patterns, time to first morning cigarette, and quit attempts in the past. Additionally we examined longitudinally the relationship between stages and expired carbon monoxide concentrations, the number of cigarettes, and yields of cigarettes. In the cross-sectional study there were significant differences among stages on expired carbon monoxide concentrations (P = 0.006), urinary nicotine metabolite concentrations (P = 0.049), the number of cigarettes smoked per day (P = 0.001), and yields of cigarettes (P = 0.042) using analyses of variance. There were also significant differences among stages on time to first morning cigarette (P = 0.018) and quit attempts in the past (P < 0.001) using chi-square tests. In the longitudinal study for each level of elevation in stage during a one-year period, expired carbon monoxide concentrations decreased on an average of 2.3 ppm (P = 0.125) and the number of cigarettes smoked per day decreased on an average of 2.8 cigarettes per day (P = 0.07). However, the yields of cigarettes did not change during the one-year period.

Regional expression of a gene encoding a neuron-specific Na(+)-dependent inorganic phosphate cotransporter (DNPI) in the rat forebrain.

We have analyzed expression of a gene encoding a brain-specific Na(+)-dependent inorganic phosphate cotransporter (DNPI), which was recently cloned from human brain, in rat forebrain using in situ hybridization. The expression of DNPI mRNA showed a widespread but highly heterogeneous pattern of distribution in the forebrain, where hybridization signals were observed in neurons but not in any other types of cells. Neurons expressing the mRNA were far more numerous in the diencephalon than in the telencephalon. In the thalamus, a number of neurons with high levels of signals were localized to all nuclei of the dorsal thalamus, habenular nuclei and subthalamic nucleus, but not the reticular nucleus and zona incerta. Moderate signal levels were seen in many neurons throughout the hypothalamus, particularly the ventromedial, paraventricular, supraoptic and arcuate nuclei, lateral hypothalamic area and mammillary complex. In contrast, expression of DNPI mRNA in the telencephalon was generally at a low level and occurred locally in some restricted regions within the neocortex, retrosplenial cortex, piriform cortex, olfactory regions, hippocampal formation and medial amygdaloid nucleus. The present results suggest that DNPI functions in heterogeneous neuron populations as a neuron-specific Na(+)-dependent inorganic phosphate cotransport system predominantly expressed in the diencephalon of the rat.

Congenital balloon digits in two neonates caused by constriction rings.

Balloon digits were found in two neonates with congenital constriction ring syndrome. The affected digits were the right long finger and right great toe. They were surgically treated at the age of 10 and 9 days, respectively. Morphologic improvement was dramatic after surgery. In cases with extensive enlargement, severe cyanosis, redness, and no subsidence of edema within several days after birth, early operative treatment may be necessary to maintain digit viability and prevent autoamputation due to circulatory embarrassment. It can also be helpful to prevent fibrosis of the subcutaneous tissue. Pathologic examination revealed marked proliferation of fibrous tissue and lymphatic vessels.

Up-regulation of galectin-3 in acute renal failure of the rat.

Galectin-3, a multifunctional beta-galactoside-binding lectin, is known to participate in development, oncogenesis, cell-to-cell attachment, and inflammation. We studied to determine whether galectin-3 is associated with cell injury and regeneration in two types of acute renal failure (ARF), namely ischemic and toxic ARF. In ischemia/reperfusion renal injury in rats (bilateral renal pedicles clamped for 40 minutes), galectin-3 mRNA began to increase at 2 hours and extended by 6.2-fold at 48 hours (P: < 0.01 versus normal control rats), and then decreased by 28 days after injury. In addition, a significant negative correlation between galectin-3 mRNA expression and serum reciprocal creatinine was shown at 48 hours after injury (n = 13, r = -0.94, P: < 0.0001). In folic acid-induced ARF, galectin-3 mRNA was found to be up-regulated at 2 hours after injury and increased levels continued until at least 7 days post-injury. In immunohistochemistry, at 2 hours following reperfusion, galectin-3 began to develop in proximal convoluted tubules. From 6 hours up to 48 hours, galectin-3 was also found in proximal straight tubules, distal tubules, thick ascending limbs, and collecting ducts. In later stages of regeneration, galectin-3 expressions were found in macrophages. In conclusion, we demonstrated that galectin-3 expressions were markedly up-regulated in both ischemic and toxic types of ARF. Galectin-3 may play an important role in acute tubular injury and the following regeneration stage.

A RUNX2/PEBP2alpha A/CBFA1 mutation displaying impaired transactivation and Smad interaction in cleidocranial dysplasia.

Cleidocranial dysplasia (CCD), an autosomal-dominant human bone disease, is thought to be caused by heterozygous mutations in runt-related gene 2 (RUNX2)/polyomavirus enhancer binding protein 2alphaA (PEBP2alphaA)/core-binding factor A1 (CBFA1). To understand the mechanism underlying the pathogenesis of CCD, we studied a novel mutant of RUNX2, CCDalphaA376, originally identified in a CCD patient. The nonsense mutation, which resulted in a truncated RUNX2 protein, severely impaired RUNX2 transactivation activity. We show that signal transducers of transforming growth factor beta superfamily receptors, Smads, interact with RUNX2 in vivo and in vitro and enhance the transactivation ability of this factor. The truncated RUNX2 protein failed to interact with and respond to Smads and was unable to induce the osteoblast-like phenotype in C2C12 myoblasts on stimulation by bone morphogenetic protein. Therefore, the pathogenesis of CCD may be related to the impaired Smad signaling of transforming growth factor beta/bone morphogenetic protein pathways that target the activity of RUNX2 during bone formation.

Neutrophil elastase inhibitor, ONO-5046 suppresses ozone-induced airway mucus hypersecretion in guinea pigs.

To investigate the role of neutrophil elastase in ozone-induced airway hypersecretion, we measured goblet cell secretion by using a semiquantitative morphometric technique in guinea pigs. The magnitude of mucus discharge was estimated from the mucus score, which is inversely related to the degree of mucus discharge in histological sections of trachea stained for mucus glycoprotein with periodic acid Schiff/Alcian blue. Mucus hypersecretion of goblet cells was induced by ozone exposure and persisted for up to 5 h after exposure. Pretreatment with N-[2-¿4-(2,2-dimethyl-propionyloxy) phenyl-sulfonylamino¿ benzoyl] aminoacetic acid (ONO-5046), a specific neutrophil elastase inhibitor (200 mg/kg, intraperitoneally), significantly inhibited goblet cell hypersecretion both just after and 5 h after ozone-exposure, but the latter inhibition was not complete. In bronchoalveolar lavage fluid, ozone exposure significantly increased the number of neutrophils just after and 5 h after exposure, while ONO-5046 significantly inhibited the increase in neutrophils only 5 h after ozone-exposure. These results indicate that neutrophil elastase may play an important role in the ozone-induced tracheal goblet cell hypersecretion and influx of neutrophils.

PEBP2alphaA/CBFA1 mutations in Japanese cleidocranial dysplasia patients.

Cleidocranial dysplasia (CCD) is an autosomal dominant human bone disease whose genetic locus has been located on chromosome 6p21, where the PEBP2alphaA/CBFA1 gene essential for osteogenesis also maps. Previously, several heterozygous mutations in PEBP2alphaA/CBFA1 were found in CCD patients. In this study, we identified six different types of mutations in PEBP2alphaA/CBFA1 in Japanese CCD patients. Four cases were similar to those reported previously: two were nonsense mutations in the Runt domain, one was a hemizygous deletion, and the other was a missense mutation in the Runt domain which abolished the DNA-binding activity of Runx2/PEBP2alphaA/CBFA1. The remaining two mutations were novel: one had a heterozygous gt-to-tt mutation at the splice donor site (gt) between the exon3-intron junction, which resulted in abnormal exon3 skipping, and the other had a mutation in exon7, which led to the introduction of a translational stop codon in the middle of the transactivation domain. Thus, defects in either the DNA-binding domain or transactivation domain of Runx2/PEBP2alphaA/CBFA1 can cause CCD. The results not only provide a strong genetic evidence that mutations involving in PEBP2alphaA/CBFA1 contribute to CCD, but also provide a useful tool to study how Runx2/PEBP2alphaA/CBFA1 plays its pivotal role during osteoblastic differentiation.

Developmentally and regionally regulated expression of growth hormone secretagogue receptor mRNA in rat brain and pituitary gland.

Distribution and development of growth hormone secretagogue receptor (GHS-R) mRNA expression in rat brain and pituitary gland were examined using ribonuclease protection assay. In adult male rats, GHS-R mRNA levels were highest in the pituitary gland, whereas those in the hypothalamus and hippocampus were 57 and 30% of those in the pituitary gland, respectively. Less abundant but detectable levels of GHS-R mRNA were found in the midbrain, pons, and medulla oblongata, but expression was barely detectable in the cerebellum and cerebral cortex. The expression of GHS-R mRNA was detected at late gestation (embryonic day 19) in the pituitary gland, hypothalamus, and brainstem. The mRNA levels increased with age in the pituitary gland, and decreased postnatally in the brainstem, while they remained constant in the hypothalamus during development. In contrast, GHS-R mRNA was not detectable in the hippocampus during the fetal period, but was first detected on postnatal day 7. Expression of GHS-R mRNA was also examined in the spontaneous dwarf rat (SDR), a model for isolated GH deficiency, to examine alterations in GHS-R mRNA expression in a GH-deficient state. GHS-R mRNA levels in the pituitary gland of SDRs were higher than those of control rats, suggesting negative regulation of GHS-R mRNA by GH in this region. GHS-R mRNA levels increased in the hypothalamus of female, but not in male SDRs. In contrast, GHS-R mRNA levels were not affected by GH in the brainstem and hippocampus. These results indicate that region-specific, developmentally regulated expression of GHS-R mRNA may reflect divergent physiological roles of GHS/GHS-R in distinct regions of the central nervous system and the pituitary gland.