Activation of specific glutamate receptor subtypes increases C-fos proto-oncogene expression in primary cultures of neonatal rat cerebellar granule cells.

In primary cultures of rat cerebellar granule cells the activation of excitatory amino acid receptors by 1-glutamate enhances the steady state level of c-fos proto-oncogene messenger RNA. This effect is blocked by magnesium (1mM) as well as by the glutamate receptor antagonist 2-amino-5-phosphono-valerate (APV). Among the other excitatory amino acid agonists N-methyl-D-Aspartate (NMDA) and quisqualate also increased c-fos mRNA content, the latter however to a significantly lesser extent, while kainate failed to modify the basal level of c-fos expression. The addition of the muscarinic agonist carbachol or of the inhibitory neurotransmitter GABA did not affect the basal level of c-fos mRNA. This data demonstrate for the first time that activation of signal transduction at a specific excitatory amino acid receptor subtype can increase the steady state level of c-fos proto-oncogene mRNA in primary culture of cerebellar neurons.

Portal hypertension after bile duct obstruction: effect of bile diversion on portal pressure in the rat.

Biliary obstruction of 14 and 28 days induced in the rat an increase of portal pressure (PP) and wedge hepatic vein pressure (WHVP); the higher these were, the longer was the obstruction. Occurrence of portal hypertension seemed related to portal and periportal fibrosis. Relief of obstruction after 14 days by bilioduodenal anastomosis brought back to normal PP and WHVP. In rats with longer obstruction periods, bilioduodenal anastomosis failed to lower PP and WHPV although biological signs of cholestasis returned to normal levels. These results suggest that portal hypertension may arise very shortly after biliary obstruction in rats and that it may persist in animals with a prolonged biliary obstruction despite an efficient bile drainage. In clinical conditions, such results would favor early treatment of lesions that usually cause prolonged bile duct obstruction, such as postoperative bile duct stenosis.

Temporary liver transplantation in acute liver failure.

The ability of a heterotopic graft to prolong life in animals dying in hepatic coma due to liver necrosis has never been definitely established. Acute hepatic failure was produced in 15 dogs by an hour of total interruption of the hepatic blood supply. Nine dogs received an intrathoracic hepatic homograft concurrently. Nontransplanted dogs died within 21 hours in hepatic coma, while transplanted dogs survived significantly longer (P less than .001). In all transplanted dogs, biological signs of hepatic failure were corrected in 24 hours. In four animals, the graft was removed on the fifth postoperative day. Two of those survived for 10 and 15 days respectively with normal hepatic function. These results demonstrate that a temporary heterotopic liver transplant is able to support life during the acute, normally lethal phase in dogs with massive liver necrosis.

Alterations of biological parameters in mice chronically exposed to low-frequency (50 Hz) electromagnetic fields.

In an experimental study we measured changes in hematological, biochemical and cortisol parameters in 6-week-old Swiss mice continuously exposed to ELF generated by a transformer station and high current bus bars. Mean daily exposure of 5.0 microT was maintained for 350 days. Hematological parameters were compared to those of control mice (n=12) exposed to a field level lower than 0.1 microT. Serum biochemical parameters (sodium, potassium, chloride, calcium, magnesium, phosphorus, amylase, creatine phosphokinase, and lactate dehydrogenase) were measured after 28 days of exposure and serum cortisol after 90 and 190 days. Granulocyte/macrophage colony-forming cells (GM-CFC) were counted at the end of the 350-day exposure. On day 20, exposed animals showed a significant decrease in leukocyte, erythrocyte, lymphocyte and monocyte counts and in hemoglobin and hematocrit values, while MCV increased. On days 43 and 63 no significant difference was observed in leukocyte and erythrocyte values, as if hemopoiesis had recovered. On day 90, a significant fall in the leukocyte, polynuclear neutrophil and eosinophil counts was observed in the exposed animals. No significant difference was noted in the biochemical parameters studied. On day 190, exposed animals had neutropenia and a decrease in the cortisol value. On day 350, no significant difference in hematological parameters was noted. Individual differences in sensitivity were observed, as 8 mice in the exposed group showed a significant decrease in the leukocyte, polymorphonuclear neutrophil and GM-CFC counts, while in two mice there was a significant increase in these same values compared to those unexposed mice.

Human T-cell lymphotropic virus-1-positive T-cell leukemia/lymphoma in a child. Report of a case and review of the literature.

Adult T-cell leukemia/lymphoma is a monoclonal T-cell neoplasm associated with human T-cell lymphotropic virus-1 (HTLV-1) that occurs almost exclusively in adults. This report concerns a Romanian girl who had recurrent skin eruptions since infancy, subcutaneous tumors in childhood, and peripheral blood lymphocytosis, which initially developed at the age of 12 years. The circulating lymphocytes were of helper T-cell immunophenotype. Serologic studies demonstrated a number of HTLV-1 antigens in the child and her mother, and molecular analyses revealed monoclonal T-cell-receptor gamma gene rearrangement and detectable HTLV-1 proviral DNA. Conventional cytogenetic studies revealed a t(3;6)(q23;q27) chromosome translocation in most of the neoplastic cells. The patient initially responded well to interferon alfa therapy and showed regression of skin lesions and diminished lymphocytosis, but 4 years later, she developed massive lymphadenopathy and leukemic infiltration of the breast. At last clinical follow-up, at the age of 17 years, the patient had stable low-level peripheral lymphocytosis and subcutaneous tumors while being continuously treated with interferon alfa. Our review of the literature revealed six additional children with HTLV-1-associated T-cell leukemia/lymphoma, including one case with a similar clinical presentation and ethnic background. To our knowledge, the t(3;6)(q23;q27) translocation identified in this patient's neoplasm has not been previously reported in adult T-cell leukemia/lymphoma cases and may explain the early onset of disease. Although adult T-cell leukemia/lymphoma is rare in Romania, the identification of healthy carriers and vertical transmission raise the possibility that Romania might be an endemic region for HTLV-1 infection.

[Adenoma of the liver in man]. / L'adénome du foie chez l'homme.

The authors report the case of a 28-year-old man with a solitary adenoma of the liver. The tumor was detected because of a raised erythrocyte sedimentation rate and serum fibrinogen. Review of the literature shows that adenoma of the liver is an uncommon tumor in man since only 30 other cases have been reported. The tumor is often multiple (55 p. 100) and the clinical manifestations are quite different from those observed in women: the adenoma is often asymptomatic (45 p. 100) and rupture is rare (10 p. 100). Androgens seem to be implicated in the development of adenoma in man since 8 out of 31 patients had received androgens for a long period of time; androgens also seem to favor the tumor's rupture.

[Hepatocellular carcinoma in a non-cirrhotic liver. Anatomo-clinical study of 22 cases of hepatectomy. Histo-prognostic factors]. / Carcinome hépato-cellulaire sur foie non cirrhotique. Etude anatomo-clinique de 22 cas d'hépatectomies. Facteurs histo-pronostiques.

The present clinicopathological study concerns 22 cases of hepatocellular carcinoma in non cirrhotic liver; they all underwent hepatectomy performed in the same surgical unit, and this group is clinically homogeneous. This cancer shows higher frequency in males (17/22), and in ages between 40 and 72. No etiologic relevance is shown. An abdominal mass is detected as first clinical symptom. Macroscopically: the tumor most often appears as a chief nodule 2-4 cm in diameter surrounded by smaller ones, always in close proximity. Histologically: the tumors are usually well or rather well differentiated hepatocarcinomas; 4 of them are fibrolamellar. Because of these macroscopical features and because of the absence of metastasis at the time of laparotomy even in case of recurrence, partial hepatectomy seems justified. A rich reticulin framework and its even distribution seem to be the best morphological signs indicating good prognosis. Long lasting survival, exceeding 11 years for one patient, concerns chiefly fibrolamellar tumors.

Transcriptional and posttranscriptional mechanisms involved in the interleukin-1, steroid, and protein kinase C regulation of nerve growth factor in cortical astrocytes.

Neonatal rat cortical astrocytes in primary culture synthesize and secrete nerve growth factor (NGF). Treatment of astrocytes with interleukin-1 beta (IL-1) or the protein kinase C (PKC) activator 12-O-tetradecanoylphorbol 13-acetate (TPA) increased NGF mRNA content by six- to 10-fold, followed in time by increases in cell content and cell secretion of NGF. Dexamethasone potently inhibited the effects of IL-1 and TPA on astroglial cell NGF expression. The action of IL-1 was not mediated by PKC because treatment of cells with maximal concentrations of both IL-1 and TPA gave an additive increase in NGF mRNA content and NGF secretion, and because down-regulating PKC activity failed to inhibit the stimulatory effects of IL-1. Moreover, both agents increased NGF gene transcription in nuclear run-on assays, but only IL-1 significantly stabilized the NGF mRNA. An analysis of the effects of IL-1 and TPA on immediate early gene expression indicated that IL-1 preferentially induced c-jun gene expression, whereas TPA greatly increased c-fos and zif/268 gene expression. These results suggest that IL-1 activates c-jun and NGF gene expression, and NGF mRNA stabilization in astrocytes by a distinct PKC-independent signaling pathway.

Effect of a protracted antidepressant treatment on signal transduction and [3H](-)-baclofen binding at GABAB receptors.

In membranes prepared from frontal cortex of rats receiving desmethylimipramine (10 mg/kg i.p. twice daily) or imipramine (7.5 mg/kg i.p. twice daily) for 3 weeks, the density of high-affinity gamma-aminobutyric acid (GABA)B recognition sites is increased when measured by [3H]GABA binding in the presence of an excess of bicuculline, but it is unchanged when measured by [3H](-)-baclofen binding. When the atypical antidepressant maprotiline was administered (10 mg/kg i.p. twice daily for 3 weeks), no change in the density of GABAB recognition sites was observed using either [3H]GABA or [3H](-)-baclofen as ligands. In addition, a protracted treatment with imipramine, desmethylimipramine and maprotiline failed to change GABAB receptor-coupled signal transduction as monitored by the ability of (-)-baclofen to inhibit the forskolin-stimulated adenylate cyclase activity in membranes prepared from frontal cortex and hippocampus or the cyclic AMP formation in slices from frontal cortex. Hence, after protracted antidepressant treatment, the increase of [3H]GABA binding may not reflect changes in the characteristics of the recognition sites of the GABAB receptors subclass coupled to the adenylate cyclase through a guanine nucleotide binding protein inhibitory (Ni).

Enhancement of Aflatoxin B1 induced liver carcinogenesis by portal diversion in the rat.

Conflicting results have been reported on the influence of portacaval anastomosis on liver carcinogenesis. The purpose of this investigation was to study the effect of portal diversion on liver carcinogenesis induced in the rat by a potent chemical liver carcinogen, Aflatoxin B1 (AFB1). Liver tumors appeared earlier and were significantly bigger in rats with shunts than in sham-operated controls. Portal diversion also induced in rats fed AFB1 a splenic atrophy with nearly complete disappearance of Malpighian corpuscles suggesting a profound immunodepression. This might be responsible for the enhancement of liver cancer by portacaval anastomosis in the rats fed AFB1. Thus, the influence of portal diversion on liver cancers appears to be multifactorial.

Transcriptional program coordination by N-methyl-D-aspartate-sensitive glutamate receptor stimulation in primary cultures of cerebellar neurons.

In primary cultures of rat cerebellar neurons, a brief stimulation of glutamate receptors results in coordinated activation of a programmed early gene response involving increases in the amount of c-fos, c-jun, jun-B, and zif/268 mRNAs. Each of these genes was induced to a different extent and showed a temporal pattern characterized by either a monophasic "early" response, occurring within 30 min of glutamate addition, or a biphasic response (c-jun), lasting for up to 6 to 8 hr after the initial stimulus. The early phase of the glutamate-induced gene expression was prevented by 3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid, a highly selective isosteric antagonist of the N-methyl-D-aspartate (NMDA)-sensitive glutamate receptor (NMDA receptor). The second phase of the c-jun response was not blocked when the NMDA receptors were completely inhibited after the initial pulse of agonist or when the quisqualate-kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione was added, suggesting that a brief NMDA receptor stimulation triggers a cascade of events critical for the manifestation of the delayed c-jun expression. Furthermore, gel retardation assays demonstrated that NMDA receptor activation results in a prolonged increase in nuclear DNA-binding activity specific for the AP-1 transcriptional regulatory element. Protein immunoblot analysis showed that the composition of this nucleoprotein complex changes as a function of time, reflecting a cascade that involves an increased translation of Fos and several Fos-related proteins. The coordinated induction of several different transcription factors and the variations in transcriptional complex formation initiated by NMDA receptor stimulation may be a key mechanism in the orchestration of specific target gene expression that underlies various aspects of neuronal function, including plasticity responses.

Werner protein recruits DNA polymerase delta to the nucleolus.

Werner syndrome is a Mendelian disorder of man that produces a number of manifestations resembling human aging. This disorder is caused by inactivation of the wrn gene, a member of the RecQ family of DNA helicases. The helicase and exonuclease activities of the Werner protein (WRN) suggest that it functions in DNA transactions, but the physiological function of WRN remains elusive. We present several lines of evidence that WRN interacts specifically with the p50 subunit of polymerase delta, the major DNA polymerase required for chromosomal DNA replication. P50, identified by yeast two-hybrid screening, interacts physically with the C terminus of WRN. Native WRN protein coimmunoprecipitates with p50 in a cellular fraction enriched in nucleolar proteins, and this immunocomplex also includes p125, the catalytic subunit of polymerase delta. In subcellular localization studies of cells transfected with WRN, p50 and p125 redistribute to the nucleolus and colocalize with WRN. These results suggest that one of the functions of WRN protein is to directly modify DNA replication via its interaction with p50 and abet dynamic relocalization of the DNA polymerase delta complexes within the nucleus.