Ethanol suppresses L-arginine-induced relaxation response of rat aorta stimulated with bacterial lipopolysaccharide

Using isolated rat aortic strips without endothelium, we investigated the effect of ethanol on L-arginine-induced relaxation. L-Arginine (10(-5)-10(-3) M) produced a relaxation response in vascular strips incubated for 6 hr with bacterial lipopolysaccharide (1 microgram/ml). The relaxation was either abolished by cycloheximide (10(-5) M) and actinomycin D (10(-5) M) or diminished by polymyxin B (10 micrograms/ml), dexamethasone (10(-5) M) and nitro-L-arginine (10(-4) M) under conditions in which these inhibitors were coincubated with lipopolysaccharide. Also, L-arginine-induced relaxation was significantly inhibited when ethanol (200, 400 mM) was present together with lipopolysaccharide during the 6-hr incubation. However, when ethanol was added to the organ bath after 6-hr incubation with lipopolysaccharide, it did not inhibit the relaxation. These results suggest that the relaxation response to L-arginine is mediated by an inducible type of nitric oxide synthase, which can be induced by lipopolysaccharide, and that ethanol may attenuate this nitric oxide-mediated relaxation by inhibiting expression of inducible nitric oxide synthase.

A 6-day intracerebroventricular infusion of the growth hormone-releasing peptide KP-102 stimulates food intake in both non-stressed and intermittently-stressed rats

The effects of a 6-day intracerebroventricular (i.c.v.) infusion of KP-102, a growth hormone-releasing peptide (GHRP), on food intake and body weight gain were observed in free-feeding rats that were or were not subjected to intermittent electric footshock stress during the 6 days. Food intake and body weight were significantly lower in rats exposed to a 60-min period of footshock twice a day for 6 days compared to non-stressed rats. A 6-day, i.c.v. infusion of KP-102 significantly and steadily increased food intake and body weight in free-feeding non-stressed rats compared to control rats receiving saline i.c.v. In rats exposed to intermittent footshock stress during the 6-day infusion, KP-102 treatment stimulated feeding behavior and resulted in significantly higher body weight compared to stressed rats that received i.c.v. infusion of saline. These results indicate that during a 6-day continuous i.c.v. infusion of GHRP, KP-102, food intake and body weight steadily increased without attenuation of the GHRP effect in both non-stressed rats and those subjected to intermittent stress.

Inhibitory effects of aclarubicin on nitric oxide production in aortic smooth muscle cells and macrophages

The effects of aclaruhicin (ACR), an anthracycline antibiotic, on inducible nitric oxide (NO) synthesis was investigated in rat aortic smooth muscle cells (RASMCs) and RAW macrophages. ACR at concentrations as low as 0.1 microM significantly inhibited NO production induced by interleukin-1beta in RASMCs. About 5- to 10-fold higher concentrations of ACR were required for inhibition of interferon-gamma and lipopolipopolysaccharide-induced NO production in RAW cells. When ACR was subsequently administered to inducible NO synthase (iNOS) induction, the NO production was barely suppressed in RASMCs. Moreover, ACR (up to 10 microM) lacked direct inhibitory effects on iNOS activity in homogenates of these cells. ACR (0.1 microM) inhibited the expression of iNOS protein and mRNA in RASMCs without concomitant cytotoxic effects. ACR (>0.5 microM)-induced inhibition of NO production in RAW cells was associated with substantial cytotoxic effects as shown by measurement of lactate dehydrogenase release. These results suggest that ACR is a potent inhibitor of iNOS induction in vascular smooth muscle, but inhibits iNOS induction in macrophage only at high cytotoxic

Psychological stress increased corticotropin-releasing hormone mRNA and content in the central nucleus of the amygdala but not in the hypothalamic paraventricular nucleus in the rat

The central administration of corticotropin-releasing hormone (CRH) to experimental animals sets into motion a coordinated series of physiological and behavioral events that promote survival during threatening situation. A large body of evidence suggest that CRH in the central nucleus of the amygdala (CEA) induces fear-related behaviors and is essential to fear conditioning; however, evidence of CRH-mediated activation of the amygdala under physiological situation is still limited. We report here a study of the impact of a psychological stressor on hypothalamic and amygdala CRH systems in the rat. Non-footshocked rats placed in a floored compartment surrounded by footshocked rats were defined as the psychological stress group. Rats were exposed to psychological stress for 15 min, and then sacrificed 1.5 and 3 h after cessation of stress. We found that our psychological stressor induced an increase in both CRH mRNA levels, as assessed by in situ hybridization histochemistry, and CRH content, as assessed by micropunch RIA, in the CEA. Exposure to the psychological stressor also caused a significant increase in CRH mRNA levels with a trend for an increase in CRH content in the dorsolateral subdivision of the bed nucleus of the stria terminalis (BNST) which is anatomically associated with the CEA. In contrast, psychological stress induced a small, but significant increase in type-1 CRH receptor (CRHR-1) mRNA in the hypothalamic paraventricular nucleus (PVN), while it failed to elevate either PVN CRH mRNA levels or content, CRH content in the median eminence (ME), or levels of plasma ACTH or corticosterone (CORT). Thus, in the context of a psychological stressor, the activation of the amygdala CRH system can occur without robust activation of the hypothalamic CRH system. In the light of previous data that the psychological stress-induced loss of sleep was reversed by the central administration of a CRH antagonist, these data suggest that CRH in the CEA may contribute to the psychological stress-evoked fear-related behavior such as hyperarousal. These data also indicate that in response to a psychological stressor, the amygdala CRH system is much more sensitive than is the CRH system emanating from the PVN.

Effect of insulin-like growth factor-I on growth hormone-releasing factor receptor expression in primary rat anterior pituitary cell culture

We examined the effect of insulin-like growth factor-I (IGF-I) on GH-releasing factor (GRF) receptor expression in the primary rat anterior pituitary cell culture. The levels of GRF receptor mRNA were dose-dependently reduced by IGF-I treatment for 24 h. To clarify whether altered levels of GRF receptor mRNA contribute to GRF receptor concentrations, we examined the GH response to GRF in vitro. There was no difference in basal GH secretion between control and IGF-I pretreated cells, while GRF-stimulated GH secretion in cells pretreated with IGF-I for 24 h was significantly lower than that in control cells. Moreover, specific [125I] Tyr10-human GRF binding to pituitary cells was reduced significantly by IGF-I treatment. These results suggest that IGF-I acts directly on the pituitary and participates in the regulation of GRF receptor expression.

Ectopic corticotroph adenoma in the cavernous sinus: case report

OBJECTIVE AND IMPORTANCE

Adrenocorticotropin (ACTH)-secreting pituitary adenomas causing Cushing's disease are often difficult to identify because of their variable locations and their small size. This report presents histological evidence of an ectopic ACTH-secreting adenoma located entirely within the cavernous sinus.

CLINICAL PRESENTATION

A 62-year-old woman presented with central obesity, hypertension, and osteoporosis. Endocrinological evaluation suggested the presence of an ACTH-secreting pituitary adenoma; however, imaging studies, including dynamic magnetic resonance imaging, did not reveal any visible lesions in the pituitary gland. Bilateral cavernous sinus sampling demonstrated a large central/peripheral ACTH gradient, with a right/left ACTH gradient. The patient was treated as having pituitary-dependent Cushing's disease, until she died suddenly as a result of acute respiratory failure.

INTERVENTION

In a postmortem histological examination, an ACTH-secreting adenoma was found in the right cavernous sinus, which was completely surrounded by dura mater and had no direct connection with the pituitary gland.

CONCLUSION

Although they are rare, such adenomas located in the cavernous sinus should be recognized as one of the reasons for inaccurate cavernous sinus sampling and the failure of transsphenoidal surgery for patients with ACTH-dependent Cushing's syndrome.

Intraosseous ganglion of the metatarsal bone

We describe a rare case of intraosseous ganglion arising in the metatarsal bone. Radiographs revealed an osteolytic lesion with a fracture in the third metatarsal bone. A biopsied specimen exhibited hyaline fibrous tissue with marked myxoid change. Gadolinium-enhanced MRI, which revealed the network-like enhancement of the rim of the lesion and polycystic lesions adjacent to the joint, was helpful in making a diagnosis of intraosseous ganglion.

Effects of antitumor agents on inducible prostacyclin production in vascular smooth muscle

The effects of various antitumor agents were examined on prostacyclin production induced by interleukin-1beta in rat aortic smooth muscle cells. Stimulation of the cells with interleukin-1beta (2.5 ng/ml) resulted in a great increase of prostacyclin production, which was abolished by indomethacin (1 microM) or cycloheximide (2 microM). Daunorubicin at 0.1-1 microM inhibited the inducible prostacyclin production in a concentration-dependent manner. However, other antitumor agents (cyclophosphamide at 1-100 microM, 5-fluorouracil at 1-100 microM and vincristine at 1-100 nM) tested did not significantly affect it. Protein expression of cyclooxygenase-2 induced by interleukin-1beta was inhibited by daunorubicin at 0.1-1 microM, but was not affected by other antitumor agents. These results suggest that daunorubicin inhibits induction of cyclooxygenase-2 and subsequent prostacyclin production in rat aortic smooth muscle cells.

Reduced growth hormone receptor messenger ribonucleic acid in an aged man with chronic malnutrition and growth hormone resistance

A severely malnourished 87-yr-old man presented with hypoglycemia. Serum GH levels were elevated, and serum levels of insulin-like growth factor I (IGF-I), IGF-binding protein-3, and GH-binding protein were extremely reduced. The patient's GH was biologically active. Administration of GH for 4 consecutive days resulted in a slight increment in serum IGF-I levels, but no elevation of serum IGF-binding protein-3. The expression of GH receptor messenger ribonucleic acid in the liver was greatly reduced. An autopsy revealed a Rathke's cleft cyst confined to the sella turcica. Immunohistochemical studies for GH showed that there was nothing to suggest a tumor overproducing GH. In addition, TSH levels were elevated in the presence of normal thyroid hormone levels, and there was a cluster of cells showing strong immunohistochemical staining for the TSH beta-subunit in the pituitary. In this patient, the decreased expression of GH receptor messenger ribonucleic acid in the liver may have been responsible for the GH resistance, which was probably caused by malnutrition.

Inhibitory effects of baicalein and wogonin on lipopolysaccharide-induced nitric oxide production in macrophages

In order to elucidate the mechanism of the antiinflammatory action of baicalein and wogonin, flavonoids from the root of Scutellaria baicalensis, the effects of these compounds were investigated on lipopolysaccharide-induced nitric oxide production in a macrophage-derived cell line, RAW 264.7. Baicalein (5-25 microM) and wogonin (5-50 microM) inhibited lipopolysaccharide-induced nitric oxide generation in a concentration-dependent manner. The inhibitory effect of these compounds was observed only when they were added at the start of cell incubation soon after the stimulation with lipopolysaccharide. Baicalein (25 microM) and wogonin (25 microM) also inhibited protein expression of inducible nitric oxide synthase. This inhibitory effect of wogonin was stronger than that of baicalein, which agrees with the result that wogonin showed stronger inhibition of nitric oxide production than baicalein. These results suggest that baicalein and wogonin attenuate lipopolysaccharide-stimulated nitric oxide synthase induction in macrophages and thus may help to explain the antiinflammatory action of these flavonoid compounds.

Growth hormone-releasing hormone receptor (GHRH-R) and growth hormone secretagogue receptor (GHS-R) mRNA levels during postnatal development in male and female rats

Experimental evidence suggests that differential pituitary sensitivity to hypothalamic signals exerts a role in mediating both age and sex dependent patterns of growth hormone (GH) release and synthesis. One mechanism by which pituitary sensitivity to hypothalamic GH regulators could be modified is by the differential synthesis of their pituitary receptors. In the present report we therefore studied the age and sex dependency of the expression of receptors for two known stimulators of GH release, growth hormone-releasing hormone (GHRH) and the synthetic peptidyl and non-peptidyl GH secretagogues (GHSs). Pituitary GHRH receptor (GHRH-R) and GHS receptor (GHS-R) mRNA levels were measured by reverse transcriptase-polymerase chain reaction (RT-PCR) in male and female rats at postnatal day 1, 10, 30 and 75. We also examined the age- and sex-dependent expression of the GHS-R in whole hypothalamic extracts, since the GHS-R is also expressed in a variety of nuclei within the hypothalamus and has been linked to central regulation of the GH-axis. Pituitary GHRH-R mRNA concentrations were age-dependent; the highest levels were observed in d1 pituitaries and then declined with age, reaching a nadir by d30. These results are in concordance with the age-related decline in pituitary GHRH sensitivity. In contrast, the ontogenic pattern of GHS-R expression was bimodal; GHS-R mRNA concentrations in dl and d30 pituitaries were approximately twice those at d10 and d75. These results mirror the transient increase in GHS sensitivity observed around the onset of puberty, suggesting that gonadal steroids mediate GHS-R expression. GHRH-R mRNA levels were comparable in males and females within each age while GHS-R mRNA levels were gender dependent. At d30, male GHS-R mRNA levels were 30% greater than in their female counterparts. This was reversed at d75, when females had 89% more GHS-R mRNA per pituitary and 65% more per somatotrope than did age-matched males. These sexual differences further support a role for gonadal steroids in the modulation of pituitary GHS-R synthesis. The ontogenic and gender-specific pattern of hypothalamic GHS-R expression differed from that observed for the pituitary. Hypothalamic GHS-R mRNA levels increased with age but exhibited no significant sex difference at each age tested. Taken together, these data demonstrate that changes in the levels of pituitary GHS-R mRNA, but not GHRH-R mRNA, are associated with changes in the gonadal steroid environment, thereby implicating the GHS/GHS-R signalling system as a control point in the establishment and maintenance of sexually dimorphic patterns of GH secretion.

Overexpression of fibroblast growth factor receptor 3 in a human thyroid carcinoma cell line results in overgrowth of the confluent cultures

Recent reports indicate that a gain-of-function mutation in fibroblast growth factor receptor 3 (FGFR-3) inhibits cell growth in the cartilaginous growth plates. These results suggest that FGFR-3 may be the receptor transducing growth inhibitory signals. Using reverse transcription-PCR we examined seven papillary thyroid carcinomas to determine FGFR-3 expression. Six out of the seven papillary carcinomas expressed FGFR-3. To clarify the role of FGFR-3 in thyroid carcinoma, FGFR-3 was overexpressed in an established human papillary thyroid carcinoma cell line. High levels of FGFR-3 protein were identified in cells stably transfected with the vector containing FGFR-3 cDNA. The specific binding of 125I-FGF-2 of these cells was threefold higher than that of control cells. Growth rates of cells overexpressing FGFR-3 were similar to those of control cells. However, cells overexpressing FGFR-3 continued to grow beyond the density at which control cells stopped proliferating. These results suggest that FGFR-3 in thyroid carcinoma is not involved strongly in the cell proliferation mechanism but may contribute to the malignant extension of some of the carcinomas by modifying cell contact signaling.

[Mechanism of inhibitory effects of ethanol on gallbladder contraction: differences in cases of histamine- and acetylcholine-induced contraction]

We investigated the effects of different concentrations of ethanol on contraction of gallbladder isolated from guinea pig. Ethanol at 25 mM significantly inhibited the contraction induced by histamine, but not those by KCl and acetylcholine. A higher concentration (100 mM) of ethanol inhibited both histamine-, acetylcholine- and KCl- induced contractions. The inhibitory effect of the lower concentration (25 mM) of ethanol was not observed in the presence of verapamil, an antagonist of L-type Ca2+ channel or staurosporine, a selective inhibitor of protein kinase C. Verapamil and staurosporine significantly inhibited both histamine- and acetylcholine-induced contractile responses: the inhibitory effect was more potent for the histamine contraction. Our recent study has demonstrated that contraction caused by protein kinase C activation is completely dependent on Ca2+ influx through the L-type Ca2+ channel in gallbladder smooth muscle of guinea pig. Therefore, the difference in 25 mM ethanol effect on histamine- and acetylcholine-induced contractions may be due to different degree of involvement of protein kinase C activation in the agonist-induced contraction. On the other hands, the higher concentration (100 mM) of ethanol inhibits the common pathway of contraction in gallbladder smooth muscle cells.

Low vitamin K intake effects on glucose tolerance in rats

To investigate the effects of vitamin K (VK) on pancreatic function, intravenous glucose tolerance tests were performed in rats fed with and without low VK diet (including less than 20% required vitamin K1). Plasma glucose and immuno-reactive insulin (IRI) were determined. It was found that at 0 min., plasma glucose and IRI levels in low VK group were slightly less than in the control (glucose, 204.5 +/- 21.7 vs. 229 +/- 19.6 mg/dl, IRI, 6.6 +/- 1.3 vs. 9.3 +/- 1.8 ng/ml mean +/- SEM). At 3 min. after glucose administration, plasma glucose was higher (391.8 +/- 25.6 vs. 371.8 +/- 18.7 mg/dl) and IRI, lower (11.8 +/- 2.1 vs. 18.2 +/- 3.6 ng/ml) in the low VK group. The disappearance rate of plasma glucose in the low VK group at 5-10 min. was significantly less than in the control (6.7 +/- 2.2 vs. 11.9 +/- 1.8 mg/dl/min.). Incremental IRI area at 0 to 5 min. in the low VK group is less than in the control (15.2 +/- 4.4 vs. 25.0 +/- 9.1 ng/ml/min.), but at 5-60 min. and 0-60 min., it was found to be significantly higher compared to the control (210.3 +/- 55.2 vs. 32.5 +/- 47.1 ng/ml/min. at 5-60 min.). Dietary low VK intake would thus appear to induce a tendency of poor early insulin response, and late hyperinsulinemia to the glucose load in rats.

Growth hormone-dependent regulation of pituitary GH secretagogue receptor (GHS-R) mRNA levels in the spontaneous dwarf Rat

Growth hormone secretagogues (GHSs) are synthetic peptidyl and nonpeptidyl compounds that are believed to stimulate the release of GH by a direct effect on the pituitary somatotrope and by stimulation of growth hormone-releasing hormone (GHRH) release and the suppression of somatostatin (SRIH) tone. Recently, the receptor for these pharmacologic agents was cloned and its expression localized to the pituitary and hypothalamus. The elucidation of an unique GHS receptor (GHS-R) suggests there is a yet to be identified endogenous ligand which could exert an important role in regulation of GH secretion. It is clearly established that GH acts to regulate its own production by feeding back at the level of the hypothalamus to downregulate GHRH and upregulate SRIH synthesis and by induction of IGF-I, which acts at the pituitary to block somatotrope responsiveness to GHRH. If the endogenous GHS/GHS-R signaling system is important in regulating GH release, it might be reasoned that changes in circulating GH concentrations would also directly or indirectly (via generation of IGF-I) modify GHS-R production. To test this hypothesis we used RT-PCR to examined pituitary and hypothalamic GHS-R mRNA levels in the spontaneous dwarf rat (SDR), an animal model characterized by the absence of GH due to a point mutation in the GH gene. In the absence of GH feedback regulation, SDR pituitary GHS-R mRNA levels were 385 +/- 61% greater (p < 0.01) than those observed in normal controls while SDR hypothalamic GHS-R mRNA levels were not significantly different from those in normal rats. Three-day subcutaneous infusion of rat GH by osmotic pump reduced SDR pituitary GHS-R mRNA levels to 55 +/- 9% of vehicle-treated controls (p < 0.05) but did not significantly alter hypothalamic GHS-R mRNA levels. To test if the changes in GHS-R mRNA levels observed following GH treatment were due to elevation of circulating IGF-I concentrations, SDRs were infused with recombinant human IGF-I. Replacement of IGF-I did not significantly alter either pituitary or hypothalamic GHS-R mRNA levels, indicating that GH acts independent of circulating IGF-I to regulate pituitary GHS-R expression in the SDR model.

[Analysis of air pollution and prevalence rate of allergic diseases among elementary school children in Kawaguchi and Hatogaya city]

Kawaguchi and Hatogaya City are located on the northern edge of Tokyo. We analysed between air pollution and prevalence rate of allergic diseases among elementary school children in this area. A prevalence rate of allergic diseases in 1996 May and June was as follows; bronchial asthma 13.5%, atopic dermatitis 24.5%, allergic rhinitis and/or conjunctivitis 22.8%, urticaria 12.4%, food allergy 7.8% and drug allergy 2.2%, respectively. Air pollution of this area was analysed to check the levels of nitrogen dioxide (NO2), sulfur dioxide (SO2) and suspended particulate matters (SPM). NO2 pollution was relatively high in urban area, and SPM pollution was especially high around the highways. SO2 pollution was lower than the environmental standard. No relationship was found between the prevalence rate of bronchial asthma, atopic dermatitis, allergic rhinitis and/or conjunctivitis and air pollution, but it was found that these diseases are slightly related to population density (p < 0.1, p < 0.01, p < 0.1, respectively).

Brain vasopressin is involved in stress-induced suppression of immune function in the rat

The possibility that vasopressin (VP) is involved in stress-induced suppression of immune function was examined in rats. Intermittent electrical footshock for 60 min suppressed the proliferative response of splenic T cells to the mitogen concanavalin A as well as natural killer (NK) cytotoxicity, and the former change was partially, and the latter was completely, blocked by intracerebroventricular (i.c.v.) preadministration of a V1 receptor antagonist. The footshock-induced suppression of the T cell proliferative response was completely abolished by coadministration of a corticotropin-releasing hormone (CRH) receptor antagonist and the V1 receptor antagonist. The i.c.v. administration of VP suppressed the proliferative response of splenic T cells and NK cytotoxicity in an adrenal-independent manner. These effects were completely reversed by i.c.v. preadministration of the V1 receptor antagonist. These results suggest that brain VP, in conjunction with CRH, suppresses immune function through the V1 receptor in rats under stress.

The growth hormone secretagogue KP-102-induced stimulation of food intake is modified by fasting, restraint stress, and somatostatin in rats

The effects of fasting, restraint stress, and intracerebroventricular (i.c.v.) injection of somatostatin on the growth hormone secretagogue, KP-102-induced stimulation of food intake were examined in rats. KP-102-induced stimulation of food intake was observed in freely-fed rats but not in 24-h starved rats. A 90 min period of restraint stress decreased food intake, and i.c.v. administration of KP-102 counteracted the suppressive effect of restraint on food intake. I.c.v. administration of somatostatin partially attenuated the KP-102-induced stimulation of food intake in freely-fed rats, while somatostatin itself did not change food intake. These results suggest that the stimulatory effect of KP-102 on feeding behavior is evident in freely-fed rats but not in starved rats, and that the effect of KP-102 is counteracted or attenuated by stress or somatostatin.

Serum sialic acid and ankle versus brachial arterial-pressure ratio in NIDDM

Serum sialic acid is related to mortality from cardiovascular disease and is increased in patients with diabetic microangiopathies. The purpose of this study was to examine whether serum sialic acid is associated with ischemic disease of the lower extremities, using the ankle versus brachial arterial-pressure ratio. The subjects were NIDDM patients attending diabetic clinics. They received a questionnaire on smoking and duration of diabetes, and physical examinations including measurement of blood pressure of upper and lower extremities. Fasting blood was taken for measurement of sialic acid, total and HDL cholesterol, and HbA1c. Serum sialic acid was significantly correlated with ankle versus brachial arterial-pressure ratio (r = -0.32) and HbA1c (r=0.45). The correlation with ankle versus brachial arterial-pressure ratio was evident in the patients with low ankle versus brachial arterial-pressure ratios (r = -0.66), but was not significant in those with normal ankle versus brachial arterial-pressure ratios (r=0.16). The correlation with HbA1c was significant independently of ankle versus brachial arterial-pressure ratios. Mean serum sialic acid was higher in patients with very low ankle versus brachial arterial-pressure ratios (< 0.9) than in those with normal ankle versus brachial arterial-pressure ratios (> or = 1.0) or slightly low ankle versus brachial arterial-pressure ratios (0.9 approximately 1.0). These results suggest that serum sialic acid reflects the status of blood glucose control and the progression of ischemic disease of the lower extremities in NIDDM patients.

Ethanol inhibits intra- and extracellular Ca(2+)-dependent contraction of rat aorta by different mechanisms

The mechanism of the inhibitory action of ethanol on vasoconstriction was studied by examining ethanol effects on vascular responses to different vasoconstrictive stimulants using isolated rat aorta. Ethanol pretreatment of aortic strips at 200 and 400 mM significantly inhibited contractile responses to KCl and 5-hydroxytryptamine in the standard medium. This inhibitory effect on vasoconstriction was observed whether or not the endothelium was present. Pretreatment with ethanol (400 mM) caused significant decrease of 45Ca2+ uptake induced by KCl when compared to the control. This pretreatment also significantly inhibited the contractile response to 5-hydroxytryptamine in the medium without Ca2+, decreased 5-hydroxytryptamine-stimulated inositol monophosphate accumulation, and significantly inhibited a transient contraction induced by 20 mM caffeine. Ethanol (400 mM) inhibited phorbol 12, 13-dibutyrate (PDBu)-induced contraction when Ca2+ was present in medium, but not when it was absent. These results suggest that ethanol acts on different sites of the signal transduction pathway of rat aortic smooth muscle, causing inhibition of transmembraneous Ca2+ influx through voltage-dependent Ca2+ channels, phosphoinositide hydrolysis and Ca(2+)-induced Ca2+ release. However, the cytoskeletal contractile apparatus may remain intact after ethanol treatment.

Fibroblast growth factor-2 free from extracellular matrix is increased in papillary thyroid carcinomas and Graves' thyroids

Fibroblast growth factor (FGF)-2 is stored in the extracellular matrix (ECM). We hypothesized that FGF-2 is mobilized from the ECM and binds to receptors on the surface of FGF-2 responsive cells during thyroid enlargement. To test this hypothesis, we estimated levels of FGF-2 free from ECM in thyroids by comparing the efficiency of two methods for FGF-2 extraction (low salt and high salt). Because the high salt concentration (more than 1.5 M NaCl) is necessary to release FGF-2 from the normal ECM, FGF-2 extracted by low salt is indicative of ECM-free FGF-2. Human papillary thyroid carcinomas, normal part thyroid, and Graves' thyroid tissues were homogenized separately in an extraction buffer containing either 0 M NaCl (low salt) or 2.0 M NaCl (high salt), and the concentration of FGF-2 in the extracts was measured by enzyme-linked immunosorbent assay (ELISA). The yields of low and high salt extracts of immunoreactive (ir)FGF-2 from papillary carcinomas (low salt: 40.0 +/- 7.5, high salt: 233 +/- 53 ng/g tissue, mean +/- SE) were significantly higher than those of normal thyroid tissues extracted by the corresponding salt concentration (low salt: 14.6 +/- 1.8, high salt: 123 +/- 12 ng/g tissue). On the other hand, the extractable irFGF-2 from Graves' thyroid tissues (low salt: 25.2 +/- 2.5, high salt: 135 +/- 24 ng/g tissue) were not significantly different from that of normal thyroid tissues. However, the ratio of the extractable irFGF from carcinomas and Graves' thyroids by low salt to that by high salt (0 M/2 M ratio = 0.206 +/- 0.051, 0.209 +/- 0.025) were significantly higher than that of normal thyroids (0.120 +/- 0.014) (p < 0.05). These results suggest that intratissue ECM-free FGF-2 is increased in papillary thyroid carcinomas and Graves' thyroid tissues, and therefore a greater amount of FGF-2 may be available for stimulation of FGF-2 responsive cells.

Growth hormone inhibits its own secretion by acting on the hypothalamus through its receptors on neuropeptide Y neurons in the arcuate nucleus and somatostatin neurons in the periventricular nucleus

GH secretion is regulated by hypothalamic somatostatin and GH-releasing factor. It has been postulated that GH feeds back on the hypothalamus and regulates its own secretion. We focused our attention on the action of GH in the hypothalamus in relation to GH secretion. Adult male rats were used throughout the studies, and the observation was made in conscious rats. Systemic administration of human GH induced c-fos gene expression, a marker of neuronal activity, in the hypothalamic arcuate nucleus (ARC) and the periventricular nucleus (PeV) in hypophysectomized male rats. The major cells in which c-fos gene expression was induced were neuropeptide Y (NPY) neurons in the ARC and somatostatin neurons in the PeV. GH receptor mRNA was demonstrated to be present in these neurons by in situ hybridization. The injection of a small dose of rat GH into the ARC or PeV inhibited GH secretion, whereas microinjection of IGF-I into these nuclei did not. Intracerebroventricular injection of NPY suppressed GH secretion, and this effect was abolished by anterolateral deafferentation of the medial basal hypothalamus (MBH), a procedure which disrupts the somatostatinergic input to the MBH. Taken together, these findings suggest that GH acts on NPY neurons in the ARC and somatostatin neurons in the PeV through GH receptor, and the activation of these neurons augments somatostatin release and inhibits GH secretion.

Genotype configuration in a case of primary gastric lymphoma with T-cell phenotype

T-cell malignant lymphoma of the gastrointestinal tract is rare. The genotype of gastric T-cell lymphoma remains unclear. The aim of this study was to elucidate the pathogenesis of a case of primary gastric T-cell lymphoma by using cytogenetics and molecular biology. Gastric biopsy specimens and lymphoma cells in the ascites were examined by immunocytology, cytogenetic analysis, and Southern blot analysis. The histological diagnosis of the gastric lymphoma was diffuse large cell type. T-cell markers were positive in immunocytochemistry of the gastric lymphoma cells and in FACS analysis of lymphoma cells in the ascites. All lymphoma cells in the ascites had complex abnormal karyotypes containing t(8;14)(q24;q32). Southern blot analysis revealed rearrangement of the IgH and C-MYC genes of the lymphoma cells in both the stomach and the ascites, but no comigration of the C-MYC with the JH locus could be detected. The TCR-beta and -gamma genes were in their germ-line configurations. In this patient, although the phenotype was T-cell lymphoma, the karyotype t(8;14)(q24;q32) and genotype had the characteristics of B-cell lymphoma. The unique B-cell genotype configuration and the C-MYC activation suggested that the cellular origin of this rare case of malignant lymphoma with a T-cell phenotype was quite immature lymphocytes.

Preferential inhibition by ethanol of phorbol ester-induced smooth muscle contraction of guinea pig gallbladder

In order to investigate how ethanol inhibits the contractility of gallbladder smooth muscle, the effects of different ethanol concentrations were examined on gallbladder contractile responses to stimulants which act on the smooth muscle by different mechanisms. A low concentration (25 mM) of ethanol significantly inhibited the contractile response to phorbol-12,13-dibutyrate (PDBu), but not that to KCl. It also did not significantly affect contractile response to Ca2+ ionophore A23187 in the presence of verapamil or that to Ba2+ in a medium without Ca2+. On the other hand, a higher concentration (200 mM) of ethanol significantly inhibited the contractile responses to PDBu, KCl, Ca2+ ionophore A23187 and BaCl2. These results together with our recent finding that PDBu-induced contraction of guinea pig gallbladder is completely dependent on activation of the voltage-dependent Ca2+ channel suggest that low concentrations of ethanol selectively inhibit the signal transduction of gallbladder smooth muscle cells in the pathway from activation of protein kinase C to that of the voltage-dependent Ca2+ channel, while high concentrations of ethanol inhibit the intracellular common pathway (probably in the cytoskeletal apparatus).

Interleukin-1beta administered intracerebroventricularly stimulates the release of noradrenaline in the hypothalamic paraventricular nucleus via prostaglandin in the rat

We evaluated the effect of intracerebroventricular (i.c.v.) administration of interleukin (IL)-1beta on the rectal temperature and the release of noradrenaline (NA) in the hypothalamic paraventricular nucleus (PVN) of the rat. IL-1beta increased rectal temperature at doses ranging from 300 pg to 300 ng, whereas it, at doses ranging from 3 ng to 300 ng, significantly stimulated the release of NA in the PVN measured by intracerebral microdialysis. The stimulatory effect of IL-1beta on the release of NA was blocked by the subcutaneous injection of indomethacin. These findings suggest that IL-1beta stimulates the release of NA in the PVN via prostaglandin, and that the release of NA in the PVN is not necessarily related to the increase in body temperature.