Time dependent changes in CRF and its mRNA in the neurons of the inferior olive following surgical transection of the olivocerebellar tract in the rat.

Changes in corticotropin-releasing factor (CRF) immunostaining and CRF mRNA in neurons of the inferior olive were compared following unilateral surgical transections of the olivocerebellar tract. Alterations in CRF immunoreactivity could not be observed earlier than 24 h after surgery. The difference--an accumulation in the contralateral side--was most pronounced at 3 days, and disappeared by the 7th postoperative day. On the other hand, changes in mRNA could be observed as early as 5-30 min after the transection. The most significant accumulation was present at 3 h after the cut and no difference could be observed from the 3rd day following surgery. The results suggest that changes in mRNA levels by axotomy may occur at an earlier time point than previously thought.     

Pyridoxine Deficiency and Ethanol-induced Liver Injury

It has been suggested that pyridoxine deficiency may potentiate ethanol-induced liver injury. Our purpose was to clarify the effect of pyridoxine deficiency on ethanol-associated liver injury by comparing liver histology, serum liver enzymes, and the viability of cultured hepatocytes from pyridoxine-deficient and pyridoxine-sufficient rats that had been chronically fed ethanol-enriched diets. Our data fail to substantiate that pyridoxine-deficient animals are more susceptible to the hepatotoxic effects of ethanol than pair-fed pyridoxine-sufficient controls. Furthermore, the addition of pyridoxine to hepatocyte cultures fails to prevent in vitro cytotoxicity of added ethanol. Pyridoxine deficiency may augment ethanol-induced enhancement of hepatic urea synthesis. These data suggest that pyridoxine deficiency may contribute to the abnormal plasma amino acid profiles and nitrogen balance of chronic alcoholics, but that it does not potentiate ethanol-induced liver injury.     

Connective tissue metabolism in children with chronic renal failure

To assess the characteristics of connective tissue metabolism in chronic renal failure (CRF), urinary excretion of glycosaminoglycan (GAG) fractions and hydroxyproline (HYP) was determined in ten patients with CRF and in ten age-matched healthy children. CRF was found to be associated with elevated free HYP (19.9±6.1 vs 9.8±3.6 mol/day,P<0.05) and depressed peptide HYP excretion (33.1±13.5 vs 225.2±17.7 mol/day,P<0.01), a low rate of total GAG excretion (7.0±2.4 vs 16.1±1.9 mol uronic acid/day,P<0.05) with low chondroitin 4 — sulphate + chondroitin 6 — sulphate (Ch-Ss) (14.0±9.9 vs 65.0±22.1%) and a high proportion of non-sulphated or under-sulphated fractions, i.e. hyaluronic acid + chondroitin + heparan sulphate (HA+Ch+HS) (75.3±11.4 vs 31.5±5.7%). Urinary 3-methyl-histidine (3-met-HIS) excretion and plasma essential free amino acids did not differ in the two groups. In response to haemodialysis no consistent change occurred in urinary excretion of 3-met-HIS, peptide-bound HYP, total GAG or percentage distribution of individual GAG fractions. After haemodialysis all plasma amino acids decreased significantly, and there was a significant increase in urinary excretion of free HYP (P<0.05). We conclude that the alterations in urinary excretion of total and individual GAGs observed in CRF may reflect disturbed connective tissue metabolism which does not appear to be accounted for by protein malnutrition or enhanced protein breakdown and remains uninfluenced by haemodialysis therapy.     

Analysis of the genetic variability of the 1st (CCC/ACC,P52T) and the 10th exons (bp 1012–1704) of the TSH receptor gene in Graves’ disease

We determined the genetic variability of the 1st (CCC/ACC, P52T polymorphic variant) and 10th exons (bp 1012–1704) of the TSH receptor (TSHR) gene in Graves’ disease. A total of 101 Graves’ patients and 163 control subjects were screened. The A253 mutant allele was carried by nine patients with Graves’ disease (8.91%) and 13 control subjects (7.98%) in heterozygous genotype. No significant difference in the frequency of the mutant allele was found between Graves’ patients and control subjects. These results provide evidence that the A253 polymorphism has no genetic relevance in Graves’ disease. Moreover, the DNA nucleotide sequence of 693 bp of the 10th exon (bp 1012–1704) of the TSHR gene was determined in 15 Graves’ patients. Six patients were homozygous for the wild‐type allele and nine were heterozygous for the mutant allele at the 253rd nucleotide of the first exon. No polymorphism was found in the DNA sequences obtained from leukocytes of Graves’ patients, similarly to the sequences obtained from the nine control subjects. None of the nine patients carrying the A253 polymorphism in the 1st exon of the TSHR had polymorphism in the examined part of the 10th exon, including two additional patients whose thyroid tissue was directly analysed. In all likelihood, the polymorphisms of the examined regions of either the 1st or the 10th exon of the THSR gene do not contribute to the genetic susceptibility to Graves’ disease.     

Retinoids induce Fas(CD95) ligand cell surface expression via RARgamma and nur77 in T cells

Cells from the CD4+ murine T hybridoma line IP-12-7 enter the apoptotic suicide program via the Fas ligand (FasL)/Fas-mediated pathway upon TCR stimulation. This stimulus regulates the sensitization of the Fas death pathway and the cell surface appearance of preformed FasL. The apoptosis is dependent on new mRNA and protein synthesis and involves up-regulation of nur77.Two groups of nuclear receptors for retinoic acids (RA) have been identified: retinoic acid receptors (RAR) and retinoid X receptors. IP-12-7 cells express RARalpha and RARgamma. Here we show that,in the IP-12-7 T cells, RA also induced the expression and DNA binding of nur77, and the cell surface appearance of FasL. The induction was mediated via RARgamma. Despite the induced expression of cell surface FasL, only two structurally related RARgamma-selective compounds, CD437 and CD2325, initiated apoptosis in these cells. The lack of apoptosis induction by natural RA was related to the inability of RARgamma to sensitize the Fas death-pathway. Cell surface FasL, however, was able to induce cell death in Fas-bearing target cells. Natural RA also induced the expression of FasL in phytohemagglutinin-activated peripheral murine T cells. It is proposed that therapeutically administered RA might induce apoptosis in Fas-sensitive cells via induction of FasL expression in activated Tcells.     

"Tissue" transglutaminase in AIDS

Apoptosis or programmed cell death (PCD) is an active process of cellular self-destruction, essential for embryonic development and maintenance of homeostasis of multicellular organisms. Programmed cell death induction can serve as a defence mechanism of the host against intracellular microbes. Virus infections trigger host cell apoptosis, which can either limit virus production or contribute directly to viral pathogenesis.Several independent laboratories have identified "tissue" transglutaminase (tTG) as a potentially important player of the cell death program(s). This gene is specifically expressed in cells dying during mammalian development as well as in those undergoing apoptosis in various patho-physiological and experimental settings [Eur. J. Cell Biol. 56 (1991) 170; Piacentini, M., Davies, P.J.A., Fesus, L., 1994. Tissue transglutaminase in cells undergoing apoptosis. In: Tomei, L.D., Cope, F.O. (Eds.), Apoptosis II: The molecular basis of apoptosis in disease. Cold Spring Harbor Lab. Press, pp. 143-165.]. This chapter reviews recent studies concerning the expression and the possible role of "tissue" transglutaminase (tTG) in apoptotic cells; particular emphasis is given to its expression in the cell death pathways associated with HIV infection in the immune system.We propose here that the induction of the tTG gene in cells of the immune system, as well as the detection of the isodipeptide epsilon(gamma-glutamyl)lysine in plasma, are useful markers of apoptosis and might make it possible to monitor disease progression in HIV-infected individuals.     

Dexamethasone suppression and multiple hormonal responses (TSH,prolactin and growth hormone) to TRH in some psychiatric disorders

Summary Baseline and TRH-induced changes of thyroid stimulating hormone (TSH), prolactin (PRL), and growth hormone (GH) were measured in 15 healthy control subjects and 63 psychiatric inpatients with DSM-III diagnoses of major depression (n = 19), schizophrenic disorder (n = 20), alcohol dependence (n = 10), and adjustment disorder (n = 14); baseline and postdexamethasone cortisol (CS) were also determined 3–6 days after the TRH-challenge. All patients and controls were women of similar mean age, weight, height, and they were free from interfering illness or drugs.Baseline TSH and PRL were lower in depression, TRH-induced TSH and PRL responses were lower in the whole patient group, but most markedly in depression and alcohol dependence. Postdexamethasone CS was significantly higher in depression, schizophrenia and alcohol dependence. Basal GH did not differentiate the subgroups; TRH-induced pathological GH responses were sometimes found in the patient groups. The differences were most marked quantitatively in major depression: a multivariate analysis of variance showed that TSH, postdexamethasone CS and PRL were the most important variables in separating patients from controls. A discriminant function derived from these variables classified all controls and 18 of 19 depressed patients correctly; however, 25 of the 44 other patients were also classified with depression.It was confirmed that psychiatric patients show significantly more endocrine disturbances than controls, and this was seen not only in major depression but also in at least three other conditions. Further work is needed to identify other neuroendocrine patterns more specific to depressive disorder.