Influence of disease site and activity on peripheral neutrophil function in inflammatory bowel disease.

Reactive oxygen species, released by phagocytes, are involved in tissue injury in inflammatory bowel diseases. The aim of our study was to evaluate peripheral neutrophil function in patients with ulcerative colitis (N = 66) and Crohn's disease (N = 62) with respect to disease activity and extent, using chemiluminometry after three stimuli. Twenty-seven healthy subjects were enrolled as controls. Neutrophils from ulcerative colitis and Crohn's disease patients had a significantly higher response than those from controls following phorbol myristate acetate (86.6 +/- 6.5, 173.8 +/- 11.9, 167.5 +/- 12.2 mV, P < 0.0001), formyl-methionyl-leucyl-phenylalanine (39.5 +/- 3.4, 41.3 +/- 2.7, 58.6 +/- 4.7 mV, P < 0.001), and zymosan (142.6 +/- 10.4, 223.7 +/- 8.9, 231.2 +/- 9.5 mV, P < 0.0001) administration. The increased response was observed during both active disease and remission. The highest chemiluminescence values were found in patients with active ulcerative pancolitis and ileal Crohn's disease. The activation of circulating neutrophils may indicate persistent intestinal inflammation or may be triggered by luminal factors even in the absence of symptoms.

Structural and functional evidence that a B chromosome in the characid fish Astyanax scabripinnis is an isochromosome.

Astyanax scabripinnis possesses a widespread polymorphism for metacentric B chromosomes as large as the largest chromosome pair in the A complement. On the basis of C-banding pattern, it was hypothesized that these B chromosomes are isochromosomes that have arisen by means of centromere misdivision and chromatid nondisjunction. In the present paper we test this hypothesis by analysing (i) the localization of a repetitive DNA sequence on both B chromosome arms, and (ii) synaptonemal complex formation, in order to test the functional homology of both arms. Genomic DNA digested with KpnI and analysed by gel electrophoresis showed fragments in a ladder-like pattern typical of tandemly repetitive DNA. These fragments were cloned and their tandem organization in the genome was confirmed. A 51-bp long consensus sequence, which was AT-rich (59%) and contained a variable region and two imperfect reverse sequences, was obtained. Fluorescence in situ hybridization (FISH) localized this repetitive DNA into noncentromeric constitutive heterochromatin which encompasses the terminal region of some acrocentric chromosomes, the NOR region, and interstitial polymorphic heterochromatin in chromosome 24. Most remarkably, tandem repeats were almost symmetrically placed in the two arms of the B chromosome, with the exception of two additional small clusters proximally located on the slightly longer arm. Synaptonemal complex (SC) analysis showed 26 completely paired SCs in males with 1B. The ring configuration of the B univalent persisting until metaphase I suggests that the two arms formed chiasmata. All these data provided strong support for the hypothesis that the B chromosome is an isochromosome.

Accentuated polymorphism of heterochromatin and nucleolar organizer regions in Astyanax scabripinnis (Pisces, Characidae): tools for understanding karyotypic evolution.

Astyanax scabripinnis has been considered a species complex because it presents high karyotypic and morphological variability among its populations. In this work, individuals of two A. scabripinnis populations from different streams in the same hydrographic basin were analyzed through C-banding and AgNOR. Although they present distinct diploid numbers, they show meta and submetacentric chromosome groups highly conserved (numerically and morphologically). Other chromosomal characteristics are also shared by both populations, as the pattern of constitutive heterochromatin distribution (large blocks in the telomeric regions of subtelocentric and acrocentric chromosomes) and some nucleolar chromosomes. Inter-individual variations both in the number and size of heterochromatic blocks, and in the number and localization of NORs were verified in the studied populations, characterizing them as polymorphics for these regions. The mechanisms involved in the dispersion of heterochromatin and NORs through the karyotypes, as well as the possible events related to the generation of polymorphism of those regions are discussed. Furthermore, relationships between these populations and within the context of the scabripinnis complex are also approached.

Intestinal permeability test as a predictor of clinical course in Crohn's disease.

OBJECTIVE: The clinical course of Crohn's disease is often unpredictable. The aim of this study was to select the most useful parameters able to predict clinical relapses. METHODS: One hundred-thirty Crohn's disease patients in clinical remission were followed every 4 months for 2 yr or until clinical relapse. Demographic and clinical data were recorded and intestinal permeability (lactulose/mannitol [L/M] test) and biochemical tests (white blood cell count, erythrocyte sedimentation rate, C-reactive protein, alpha1 acid glycoprotein, and serum iron) were performed at study entry. A subgroup of 54 patients had clinical follow-up and repeated tests every 4 months. RESULTS: Fifty-two patients (40%) relapsed during the 2-yr follow-up. A significant correlation was found between relapse and gender (p = 0.030) but not between relapse and age, extent and type of disease, previous surgery, or therapy. Increased L/M test (p = 0.0001) and decreased serum iron level (p = 0.0057) were associated with clinical relapse. Time-dependent analysis, performed on patients receiving serial evaluation, showed that L/M test alteration was the only variable that could predict a relapse (RR 8.84, 95% confidence interval [CI] 1.41-53.37; p < 0.05). CONCLUSIONS: The L/M test identifies Crohn's disease patients in apparent remission, but with a high risk of clinical relapse, better than clinical and biochemical indices. Different treatment strategies might be suggested for this subgroup of patients.

Effect of moderate exercise on Crohn's disease patients in remission.

BACKGROUND: Physical exercise may exacerbate the disturbed homeostasis of Crohn's disease patients. AIM: To examine the effect of moderate physical exercise on gastrointestinal function in a group of Crohn's disease patients in remission. PATIENTS AND METHODS: The effect of one-hour's exercise at a maximum of 60% oxygen consumption was evaluated in six males with ileal Crohn's disease in remission on orocaecal transit time (breath test to lactulose), intestinal permeability (6-hours' urinary excretion of a sugar mixture of lactulose/mannitol), polymorphonuclear leucocytes function (peripheral blood chemiluminescence), lipoperoxidation (plasma malondialdehyde) and antioxidant trace elements (urinary and plasma zinc and copper concentrations). Six healthy age-matched subjects served as controls. RESULTS: Exercise did not elicit subjective symptoms or changes in intestinal permeability and lipoperoxidation. Orocaecal transit time increased after exercise in Crohn's disease patients (72 min +/- 30 vs 100 min +/- 34) with no significant difference from controls (77 min +/- 20 vs 83 min +/- 23). Neutrophils, primed pre-exercise in Crohn's disease patients showed an increased post-exercise chemiluminescence similar to controls. Zinc urinary output significantly increased after exercise in Crohn's disease patients and remained unchanged in control subjects. CONCLUSIONS: Moderate aerobic exercise has no significant effect on the gastrointestinal parameters examined. However, basal neutrophil activation and exercise in Crohn's disease patients may trigger an excessive production of oxygen metabolites. Moreover, exercise may contribute to an increased risk of zinc deficiency.

Zinc therapy increases duodenal concentrations of metallothionein and iron in Wilson's disease patients.

OBJECTIVE: Wilson's disease is effectively treated by zinc administration which, in vitro, increases metallothionein concentrations. To ascertain whether the latter also occurs in humans we measured metallothionein and trace element concentrations in the duodenal mucosa of 15 Wilson's disease patients: 12 treated with zinc sulphate, two treated with penicillamine, and one not yet on treatment. The control group consisted of 17 patients with dyspepsia, who underwent the same study protocol. METHODS: Metallothionein and trace element concentrations were measured in duodenal mucosa biopsies according to the silver-saturation hemolysate method and atomic absorption spectrophotometry. RESULTS: Metallothionein concentrations increased by 1500% after zinc and 150% after penicillamine in Wilson's disease patients, with respect to controls who had negative endoscopy and Wilson's disease patients who were not treated. A significant correlation was found between metallothionein and duodenal zinc concentrations. Mucosal iron concentration increased in Wilson's disease patients whether they were treated with zinc or penicillamine. Duodenum with duodenitis also had significantly increased iron levels compared with normal duodenum. CONCLUSIONS: Zinc administration increases intestinal metallothionein in Wilson's disease patients. The blockade of copper absorption and its elimination in the stools on desquamation of the intestinal cells probably explains one of the mechanisms underlying the effect of zinc treatment. Despite normal endoscopy, Wilson's disease patients present increased mucosal iron concentrations similar to those in controls with duodenitis. Metallothionein may therefore prevent oxidative damage caused by metal toxicity.

Altered plasma and mucosal concentrations of trace elements and antioxidants in active ulcerative colitis.

BACKGROUND: The production of free radicals is increased in inflammatory bowel disease, and trace elements are crucial components of several antioxidants. Trace elements deficiency may therefore compromise the defense against oxidative damage. The aims of this study were to measure plasma and tissue concentration of trace elements and antioxidants and to relate this to disease activity. METHODS: A 10-ml blood sample and six colonic biopsy specimens were obtained from 24 patients with either active ulcerative colitis or in remission and 10 patients with irritable bowel syndrome for measurement of trace elements and trace element-dependent enzymes. RESULTS: Patients with moderately active disease had significantly lower plasma iron, selenium, and glutathione peroxidase levels than patients in remission and controls, whereas no significant differences were found between the zinc and copper values of patients and controls. Mucosal concentrations of zinc and metallothionein were reduced, whereas iron and glutathione peroxidase concentrations were increased in patients with endoscopically active disease as compared with controls and patients in remission. CONCLUSIONS: Patients with ulcerative colitis have altered plasma and tissue levels of trace elements and antioxidant-related enzymes. The resulting reduced protection against free radicals may contribute to the inflammatory process.

The X1X2Y sex chromosome system in the fish Hoplias malabaricus. II. Meiotic analyses.

The neotropical fish Hoplias malabaricus shows diversified cytotypes and may represent a group of distinct species. One of these cytotypes is characterized by 2n = 40 and 2n = 39 chromosomes in females and males, respectively, with a multiple sex chromosome system of the X1X1X2X2/X1X2Y type. The Y, representing a large chromosome in male karyotype, is derived from a translocation event between two biarmed chromosomes: one of them similar to X1 chromosome (no. 6) and another one similar to X2 chromosome (probably no. 20). Meiotic data (standard and synaptonemal complexes analyses) show 18 bivalents and one characteristic trivalent in pachytene and metaphase I spermatocytes, as well as two kinds of metaphase II cells with 19 and 20 chromosomes. The trivalent is formed by the Y, X1 and X2 chromosomes and usually presents a complete pairing in pachytene. However, trivalents with partially or fully asynapsed segments are also observed. These segments are assumed to be non-homologous regions of the X1 and X2 chromosomes without correspondence with the Y chromosome, which can heterosynapse. This behaviour of the sex trivalent leading to a fully paired structure, taken together with the close frequencies of the two spermatocyte types at metaphase II, suggests a normal pattern for male H. malabaricus meiosis, representing a stabilized multiple sex chromosome system in this species.

Effect of zinc supplementation on metallothionein, copper, and zinc concentration in various tissues of copper-loaded rats.

The present study was designed to investigate the effects of Zn administration on metallothionein concentrations in the liver, kidney, and intestine of copper-loaded rats. Male CD rats were fed a diet containing 12 mg Cu and 67 mg Zn/kg body wt. They were divided into either acute or chronic experimental protocols. Rats undergoing acute experiments received daily ip injections of either Cu (3 mg/kg body wt) or Zn (10 mg/kg body wt) for 3 d. Chronic experiments were carried out on rats receiving Cu ip injections on d 1, 2, 3, 10, 17, and 24, Cu injections plus a Zn-supplemented diet containing 5 g Zn/kg solid diet, or a Zn-supplemented diet alone. Rats injected Zn or Cu had increased MT concentrations in liver and kidney. Zn produced the most important effects and the liver was the most responsive organ. Rats fed a Zn-supplemented diet had significantly higher MT concentrations in liver and intestine with respect to controls. Increased MT synthesis in the liver may contribute to copper detoxification; the hypothesis of copper entrapment in enterocytes cannot be confirmed.

Chromosome banding and synaptonemal complexes in Leporinus lacustris (Pisces, Anostomidae): analysis of a sex system.

Leporinus lacustris had been studied previously, and shows 2n = 54 metacentric and submetacentric chromosomes, including an XX/XY system described on the basis of Giemsa-stained preparations. However, there was some doubt regarding the identification of the sex chromosomes, because of the relative homogeneity of this species karyotype. Thus, the main goal of the present study was to find new evidence of heteromorphic sex chromosomes in these fish through chromosome banding and synaptonemal complex analyses. In fact, the data obtained do not support the presence of sexual heteromorphism. The importance of these methodologies in the study of fish sex chromosomes is discussed.

Post-zygotic modifications and intra- and inter-individual nucleolar organizing region variations in fish: report of a case involving Leporinus friderici.

Silver nitrate staining, a rapid and efficient method, has proven to be excellent for nucleolar organizing region (NOR) studies in fish. Some fish appear to have only two NOR-bearing chromosomes in their karyotype, whereas others probably have several. In the present study we analyzed the NORs of Leporinus friderici, a species that, on the basis of previous studies, has been considered as representative of species with NORs carried by a single chromosome pair. The analyses were performed by a combination of three methods, i.e. silver nitrate staining, staining with the GC-specific fluorochrome chromomycin A3, and in situ hybridization with digoxigenin-labeled probes. The results showed that, although more frequent and conspicuous in a single chromosome pair, the NORs of this species are present in multiple chromosomes. Intra- and inter-individual variations observed by the three methods strongly suggest the occurrence of post-zygotic modifications involving NORs. NOR identification in fish, almost exclusively performed by the silver nitrate method, is currently being re-evaluated by methods such as chromomycin A3 staining and in situ hybridization, which may provide important information leading to a better understanding of chromosome evolution in these animals.

Regulation of the ribosomal-RNA gene-expression in fibroblasts isolated from different human or murine tissues.

Ag-NOR stainings of the fibroblastic cultures derived from skin, lung and kidney of mice and humans have shown differential regulation of rRNA gene expression. Ag-NOR activities were found to be highest in the fibroblasts derived from the lung and the lowest in the skin-derived metaphases from both mice and humans and they were intermediate in the fibroblasts of kidney from both these species. Our observations indicate further that fibroblasts derived from different tissues are different not only in producing organ-specific growth factors but also in differential expression of ribosomal cistrons. This difference can also explain why orthotopic implantation of human tumor cells into nude mice is preferential compared with ectopic implantation in tumor take and metastasis.

Clonal expansion of cells with trisomy of chromosomes 12 and X in an EBV-transformed lymphoblastoid cell line and establishment of a tumorigenic monoclonal cell line (48,XX,+X,+12).

Clonal expansion of cells with a certain abnormal chromosome constitution has been demonstrated in EBV-transformed lymphoblastoid cell lines, and a new monoclonal tumorigenic cell line (48,XX,+X,+12) has been established. Based on these data and our previous hypothesis that predisposition to tumor development could be associated with inherited susceptibility of certain chromosomes and chromosome regions to breakage, we emphasize that cytogenetic analysis of immortalized cell populations established from normal individuals and cancer patients might be of great importance for predicting development of different primary and secondary malignancies.

Heterochromatin and karyotype reorganization in fish of the family Anostomidae (Characiformes).

Mitotic chromosomes of four fish species of the family Anostomidae, belonging to the genera Leporinus, Leporellus, and Schizodon, were studied. With 2n = 54 meta- and sub-metacentric chromosomes, this family appears to be characterized by marked karyotypic stability. Although perceptible differences exist, mainly in the amount of constitutive heterochromatin present in the chromosomes of these species, these differences do not affect the structure and/or size of these chromosomes. Chromatin substitutions and/or modifications may have led, in one direction, to an increase in heterochromatin in some species and, in the opposite direction, to heterochromatin reduction in others. Whether these changes are accompanied by changes in the amount of euchromatin in the chromosomes is an open question. The nucleolar organizer regions, which may be located on different chromosomes in the various species, may also be indicators of reorganization of these karyotypes.