Task Force on Catastrophic Antiphospholipid Syndrome (APS) and Non-criteria APS Manifestations (I): catastrophic APS, APS nephropathy and heart valve lesions.

The objectives of the 'Task Force on Catastrophic Antiphospholipid Syndrome (APS) and Non-criteria APS Manifestations' were to assess the clinical utility of the international consensus statement on classification criteria and treatment guidelines for the catastrophic APS, to identify and grade the studies that analyse the relationship between the antiphospholipid antibodies and the non-criteria APS manifestations and to present the current evidence regarding the accuracy of these non-criteria APS manifestations for the detection of patients with APS. This article summarizes the studies analysed on the catastrophic APS, APS nephropathy and heart valve lesions, and presents the recommendations elaborated by the Task Force after this analysis.

Task Force on Catastrophic Antiphospholipid Syndrome (APS) and Non-criteria APS Manifestations (II): thrombocytopenia and skin manifestations.

The objectives of the 'Task Force on Catastrophic Antiphospholipid Syndrome (APS) and Non-criteria APS Manifestations' were to assess the clinical utility of the international consensus statement on classification criteria and treatment guidelines for the catastrophic APS, to identify and grade the studies that analyze the relationship between the antiphospholipid antibodies and the non-criteria APS manifestations, and to present the current evidence regarding the accuracy of these non-criteria APS manifestations for the detection of patients with APS. This article summarizes the studies analyzed on thrombocytopenia and skin manifestations, and presents the recommendations elaborated by the Task Force after this analysis.

Raman spectrum of layered tilkerodeite (Pd2HgSe3) topological insulator: the palladium analogue of jacutingaite (Pt2HgSe3).

The layered mineral tilkerodeite (Pd2HgSe3), the palladium analogue of jacutingaite (Pt2HgSe3), is a promising quantum spin hall insulator for low-power nanospintronics. In this context, a fast and reliable assessment of its structure is key for exploring fundamental properties and architecture of new Pd2HgSe3-based devices. Here, we investigate the first-order Raman spectrum in high-quality, single-crystal bulk tilkerodeite, and analyze the wavenumber relation to its isostructural jacutingaite analogue. By using polarized Raman spectroscopy, symmetry analysis, and first-principles calculations, we assigned all the Raman-active phonons in tilkerodeite, unveiling their wavenumbers, atomic displacement patterns, and symmetries. Our calculations used several exchange-correlation functionals within the density functional perturbation theory framework, reproducing both structure and Raman-active phonon wavenumbers in excellent agreement with experiments. Also, it was found that the influence of the spin-orbit coupling can be neglected in the study of these properties. Finally, we compared the wavenumber and atomic displacement patterns of corresponding Raman-active modes in tilkerodeite and jacutingaite, and found that the effect of the Pd and Pt masses can be neglected on reasoning their wavenumber differences. From this analysis, tilkerodeite is found to be mechanically weaker than jacutingaite against the atomic displacement patterns of these modes. Our findings advance the understanding of the structural properties of a recently discovered layered topological insulator, fundamental to further exploring its electronic, optical, thermal, and mechanical properties, and for device fabrication.

Osteoarthritis and rheumatoid arthritis pannus have similar qualitative metabolic characteristics and pro-inflammatory cytokine response.

OBJECTIVE: Pannus in osteoarthritis (OA) has only recently been characterized. Little is known, however, regarding the behavior of OA pannus in vitro compared to rheumatoid arthritis (RA) pannus. The purpose of our study was to compare OA with RA pannus. METHODS: Pannus and synovial tissue co-cultures from 5 patients with OA and 5 patients with RA obtained during arthroplasty were studied. Pannus was defined as the microscopic invasive granulation tissue covering the articular surface. Tissues were cultured for 7 days and stained with Alcian Blue technique. Interleukin-1beta (IL-1beta), IL-8, IL-10, IL-12, tumor necrosis factor-alpha (TNF-alpha), and interferon gamma (IFN-gamma) were also determined in supernatants by ELISA. Cartilage oligomeric matrix protein (COMP), type II collagen, TNF-alpha, IL-10 and Ki-67 expression were also detected by immunohistochemistry. RESULTS: All patients had vascular or fibrous pannus. Synovial proliferation, inflammatory infiltrates and a decrease of extracellular matrix proteins were observed in all tissue samples. Chondrocyte proliferation was lower in OA than RA cartilage. OA synovial tissue expressed lower levels of proteoglycans than RA synoyium. Type II collagen levels were lower in OA than in RA cartilage. Significantly higher levels of IL-1beta were found in the supernatants of RA pannus compared to OA pannus (p<0.05). High but similar levels of TNF-alpha, IL-8 and TIMP-1 were detected in OA and RA pannus supernatants. IL-10, IL-12 and IFN-gamma were undetectable. CONCLUSION: RA and OA pannus had similar pro-inflammatory and anti-inflammatory cytokine profile expression. OA cartilage, synovial tissue and pannus had lower production of proteoglycans, type II collagen and IL-1beta. It remains to be elucidated why OA pannus invades the cartilage surface but does not cause the marginal erosions typically seen in RA.

Glucose and acetate metabolism in bovine intramuscular and subcutaneous adipose tissues from steers infused with glucose, propionate, or acetate.

We hypothesized that abomasal infusion of glucose would promote de novo fatty acid biosynthesis from glucose in vitro in bovine intramuscular (i.m.) and subcutaneous (s.c.) adipose tissues to a greater extent than ruminal infusion of acetate, propionate, or glucose. Angus crossbred steers (n = 24), 22 mo of age, were fitted with ruminal cannulas, and steers were adapted to another corn/sorghum finishing diet over a 2-wk period while recovering from the placement of the cannulas. After the adaptation period, the steers were fed the second finishing diet at 130% of their voluntary intake and were infused with isocaloric amounts (3.76 Mcal/d) of glucose, propionate, or acetate for 35 d. Glucose was infused either into the rumen or into the abomasum, whereas propionate and acetate were infused into the rumen. Acetate infusion decreased DM and DE intakes (P < 0.05). The 5th to 8th longissimus muscle section was removed immediately and transported to the laboratory within 10 min post-exsanguination in 38 °C, oxygenated Krebs Henseleit buffer containing 5 mM glucose and 5 mM acetate. Intramuscular and s.c. adipose tissues were dissected from the muscle and incubated in vitro in 5 mM glucose plus 5 mM acetate (containing [U-14C]glucose or [1-14C]acetate). Lipid content was lower (P = 0.04) in i.m. adipose tissue of the acetate-infused steers than in the other treatment groups, and i.m. adipocytes from acetate-infused steers were smaller (P = 0.01) than those from propionate-infused steers. The rate of incorporation of acetate into glyceride-fatty acids (GFA) in i.m. and s.c. adipose tissues was greater (P < 0.03) in steers receiving ruminal or abomasal infusions of glucose than in adipose tissues from steers infused with acetate. The greatest rates of GFA synthesis were observed in s.c. adipose tissue from steers infused ruminally with propionate or abomasally infused with glucose (P < 0.001). In i.m. and s.c. adipose tissues, the proportion of acetyl units from acetate incorporated into GFA was greater in steers receiving glucose infusion in the rumen or abomasum than in steers receiving acetate or propionate infusion (P < 0.05). Contrary to our hypothesis, abomasal glucose infusion did not promote greater fatty acid biosynthesis from glucose in i.m. adipose tissue than ruminal glucose infusion. However, glucose infusion caused the greatest production of acetyl units from acetate in i.m. and s.c. adipose tissues.

Tween 20 detaches cardiolipin from ELISA plates and makes anticardiolipin antibodies undetectable regardless of the presence of beta 2-glycoprotein-I.

We investigated the effects of polyoxyethylene sorbitan monolaurate (Tween 20) in the detection of IgG anticardiolipin antibodies (aCL) by the CL-beta 2-glycoprotein-I and the standard aCL solid-phase immunoassays. We found that Tween 20 disengages cardiolipin from a variety of microtiter wells rendering aCL undetectable by both methods. Our results agree with a previous report but are discordant with others. We offer rationale that may explain some of the discrepancies. Based in our findings, we do not recommend the use of Tween 20 for the detection of aCL.

The antiphospholipid/cofactor syndromes: a primary variant with antibodies to beta 2-glycoprotein-I but no antibodies detectable in standard antiphospholipid assays.

BACKGROUND: Most systemic lupus erythematosus (SLE) patients with two or more clinical manifestations of the antiphospholipid syndrome (APS) and negative antiphospholipid antibodies (aPL) have antibodies to beta 2-glycoprotein-I (a beta 2 GP-I). Herein we describe a similar set of circumstances, but in patients without evidence of SLE. PATIENTS AND METHODS: We studied 6 patients with recurrent venous and/or arterial thromboses without aPL as detected by routine assays nor clinical or serological evidence of other autoimmune disease. Immunoglobin (Ig) G and IgM antibodies to bovine and human phospholipid-free beta 2 GP-I were studied by Western blot test and by enzyme-linked immunosorbent assay (ELISA) utilizing radiated and nonirradiated plates. We also tested antibodies to cardiolipin, phosphatidylserine, and phosphatidylethanolamine by ELISA. As controls, 54 normal sera were studied. RESULTS: All 6 patients had recurrent arterial and/or venous thromboses. Three also had thrombocytopenia, 1 had livedo reticularis, and 2 had valvular heart disease. None of the patients had aPL, but all had serum IgG reactivity against human and bovine beta 2 GP-I (P < 0.001 versus controls for both). Titers of anti-bovine beta 2 GP-I were higher when studied in irradiated plates but were also higher than normal in nonirradiated plates (P < 0.001). These antibodies did not recognize human or bovine beta 2 GP-I bound to cardiolipin in solid phase. We confirmed by Western blot that these autoantibodies recognize human beta 2 GP-I. We found no IgM a beta 2 GP-I. CONCLUSIONS: We describe a primary condition akin to the antiphospholipid syndrome with negative aPL, but with serum IgG antibodies to human and bovine beta 2 GP-I. These antibodies recognize beta 2 GP-I epitopes that are not accessible when beta 2 GP-I is bound to cardiolipin.

Decrease in serum antiphospholipid antibody levels upon development of nephrotic syndrome in patients with systemic lupus erythematosus: relationship to urinary loss of IgG and other factors.

PURPOSE: Having observed a decrease in antiphospholipid antibodies (aPL) upon the development of nephrotic syndrome, as well as a negative association between nephrotic syndrome and secondary antiphospholipid syndrome, in patients with systemic lupus erythematosus (SLE), we sought to determine if this could be due to urinary loss of aPL and/or other factors. SUBJECTS AND METHODS: IgG and IgM aPL as well as other autoantibodies were studied by enzyme-linked immunosorbent assay with cardiolipin as antigen in serum and urine from six patients with SLE who had elevated serum aPL levels and developed nephrotic syndrome (cases). For controls, we studied: (1) three SLE patients with nephrotic syndrome but low aPL levels; (2) three patients with non-SLE nephrotic syndrome; (3) three SLE patients with high-titer aPL but no proteinuria; and (4) 10 healthy volunteers. RESULTS: We found urinary IgG, but no IgM, aPL in all cases and in one control from Group 2. Serum IgG aPL had gradually decreased after the development of nephrotic syndrome and had become normal. IgM aPL had also decreased in the four patients who had elevated levels, having reached normal levels at the time of the study in two. There was an apparent correlation between serum and urine IgG aPL levels but not between urinary IgG aPL and total proteinuria. By Farr's method, we found no urinary anti-DNA despite high serum titers in three cases. The two cases and one of the controls in Group 1 who had serum antibodies to extractable antigens also had these antibodies in the urine. CONCLUSION: Urinary loss of IgG aPL during nephrotic syndrome does not completely explain the reduction in serum aPL, since IgM also decreases. There could also be decreased synthesis and/or increased catabolism of immunoglobulins.

Serum anti-beta2-glycoprotein-I and anticardiolipin antibodies during thrombosis in systemic lupus erythematosus patients.

PURPOSE: Antibodies to beta2-glycoprotein-I are more strongly associated with clinical antiphospholipid syndrome than are anticardiolipin antibodies. We previously found a decrease in anticardiolipin antibodies at the time of thrombosis in 6 patients with systemic lupus erythematosus (SLE). We therefore sought to determine the prevalence and levels of antibodies to beta2-glycoprotein-I and to cardiolipin before, during, and after thrombosis in patients with SLE, and to compare them with patients who did not have thrombosis. METHODS: We studied 24 patients with SLE who had at least one episode of thrombosis and 102 patients with SLE without thrombosis. Serum anticardiolipin antibodies were measured by conventional enzyme-linked immunosorbent assay (ELISA) using newborn calf serum as the blocking agent. Serum anti-beta2-glycoprotein-I antibodies were measured by ELISA on nonirradiated plates, using purified human beta2-glycoprotein-I without phospholipid. RESULTS: All patients with thrombosis had anti-beta2-glycoprotein-I antibodies, compared with only 17% of controls (P <0.0001). We observed a significant decrease in serum anti-beta2-glycoprotein-I levels at the time of thrombosis, as compared with previous and subsequent samples. The prevalence and levels of IgG and IgM anticardiolipin antibodies were similar in patients with and without thrombosis. A decrease in IgG or IgM anticardiolipin titers occurred during thrombosis in 6 patients. Anticoagulant, corticosteroid, and immunosuppressive treatments did not appear to affect anti-beta2-glycoprotein-I levels at the time of thrombosis. CONCLUSION: Anti-beta2-glycoprotein-I antibodies are strongly associated with thrombosis in patients with SLE. The decrease of anti-beta2-glycoprotein-I levels at the time of thrombosis may indicate a pathogenic role. This antibody may also be a marker of predisposition for thrombosis in these patients.

Antiphospholipid antibodies in patients with idiopathic autoimmune haemolytic anemia.

Isolated cases of anti-phospholipid antibody (aPL)-associated idiopathic autoimmune haemolytic anemia (IAHA) have been recently described. To assess the significances of this association, we studied by ELISA the presence of aPL in sera from 18 patients with IAHA and 14 patients with non-autoimmune haemolysis (NON-AH). Four IAHA cases and none of the NON-AH controls showed IgM anticardiolipin antibodies (aCL) that crossreacted extensively with zwitterionic as well as with other anionic phospholipids. IgG aCL were detected in 6 patients with IAHA and in 1 patient with NON-AH; there was little cross-reactivity with other phospholipids. Our results suggest that antiphospholipid antibodies are present in a substantial number of patients with IAHA. This humoral response does not seem to be secondary to the haemolysis proper. The potential pathogenic significance of this finding is discussed.

Identification of four subpopulations of IgG anticardiolipin antibodies in patients with primary antiphospholipid syndrome on the basis of their requirement for beta 2-glycoprotein-I and their unmasking by heat.

Heat-treatment of normal human serum (NHS) results in positive seroconversion of IgG anticardiolipin antibodies (aCL) that do not depend on beta 2-glycoprotein-I (beta 2GP-I) for their detection in vitro as do some IgG aCL from patients with primary antiphospholipid syndrome (PAPS). Other IgC aCL from PAPS depend on beta 2GP-I for phospholipid binding. Here, we studied heat-unmasked aCL from 22 PAPS sera and from eight normal individuals. IgG aCL were detected in standard (using new born calf serum [NBCS] that contains beta 2GP-I as blocking agent and to dilute samples) and in a modified ELISA (using beta 2GP-I-free-bovine serum albumin instead of NBCS). Overt and heat-unmasked IgC aCL were purified from CL micelles alone or mixed with purified beta 2GP-I. NHS had no overt IgG aCL. In contrast, aCL titers increased almost ten-fold after heat-inactivation of NHS, a result which was equally detectable in both assay conditions. As expected, PAPS patients had one population of overt beta 2GP-I-dependent IgG aCL. After heat-treatment of all PAPS sera, we detected IgG aCL in both standard and modified aCL ELISA with an approximately three-fold increase in IgG aCL titers when tested in the standard assay. Two PAPS patients also had a second population of beta 2GP-I-independent overt IgG aCL. Purified IgG from these PAPS sera retained both reactivities.(ABSTRACT TRUNCATED AT 250 WORDS)

Anaerobic biodegradation of an organic by-products leachate by interaction with different mine tailings.

Deinking by-products from paper recycling have been used as cover materials on acid-producing tailings. Due to residual cellulose, anaerobic degradation leads to the production of an organic-rich leachate, which may percolate through the tailings. This study aims at describing the influence of the tailings' characteristics on the attenuation of organic matter in leachate and at discussing the degradation mechanisms. To this end, leachate was mixed with different types of tailings, including three unoxidized tailings with varying acid generation potentials and one tailing in three states of oxidation. Regularly, selected biochemical parameters were analyzed to access the evolution of organic components. The results show that when leachate from deinking by-products was placed in contact with tailings, phase and acid-base balance reactions took place in the beginning. Subsequently, oxidation-reduction reactions dominated the chemistry of the system. The type, the constituents, and the state of oxidation of the mine tailings condition the mechanisms of biodegradation of organic components. Methanogenesis was predominant in the control sample (pure organic leachate) but was absent in all leachate-tailings mixtures. No biodegradation was observed in the liquid phase for oxidized tailings and the organic concentration remained constant for unoxidized tailings, independently of the acid-generation potential. The biodegradation efficiency was optimal when the leachate was in contact with a mixture of oxidized and unoxidized tailings due to sulfate-reduction.

[New molecular and clinical information about collagens]. / Novedades moleculares y clínicas de las colágenas.

Collagen is one of the most abundant proteins in human tissues. Together with other connective tissue components (non-collagenous glycoproteins, proteoglycans, laminins, thrombospondins, entactin and tenascin), collagen promotes cellular adhesion, activates intracellular signals, and regulates the biological activities of growth factors and other proteins. During the past 20 years at least 19 genetically different collagenous proteins coded by 30 distinct genes have been identified. Here, we review some new aspects of the collagens that form fibrils, sheets, or beaded filaments, and of the so-called multiplexin collagens. Whenever possible, we give insights regarding the association of the structural abnormalities of these proteins as they relate with human disease(s).

[Current concepts on cartilage collagens and their association with disease]. / Conceptos actuales sobre colágenas de cartílago y su asociación con enfermedades.

The main functional role of the collagenous cartilage fibers is to form a stable network to counteract the hydrodynamic pressure generated by the highly hydrodynamic proteoglycan aggregates. The main collagen present in human cartilage is type II, but other proteins such as type IV, VI, IX, X, XI and XIV are also found albeit in small quantities. Several transgenic mice have been developed to study the structural abnormalities as they relate to human disease. Similarly, the study of these structural abnormalities has renewed the interest regarding their pathogenetic role in some hereditary and acquired diseases of cartilage in humans. It is hoped that gene therapy will help correct these abnormalities. We review here these topics.

Clinical, histopathological, immunological and fibroblast studies in 30 patients with subcutaneous injections of modelants including silicone and mineral oils.

OBJECTIVE: To study patients with side effects secondary to the injection of modelants. METHODS: We studied their clinical, serological, histopathological, radiographic, immunoregulatory and fibroblast culture features by standard methods. We studied thirty patients, 24 women, mean age: 38.2 years. Patients had received either mineral oil, guayacol, silicone or a mixture of these substances; some had received unknown material(s). RESULTS: The mean time between the injection and the onset of symptoms was six years (range: 0.1-24 years). All patients had sclerodermatous skin changes, subcutaneous nodules, edema and/or hyperpigmentation at the site(s) of injection(s); five individuals also had skin changes at sites remote from the injection. Thirteen patients had clinical features of an autoimmune disease. Eleven patients gave a history of arthralgias including four that had symmetrical non-erosive polyarthritis. Twenty of 28 patients (71%) had positive anti-nuclear antibodies. We found intracellular spontaneous production of IL-1 (interleukin-1) by patients' macrophages which was almost absent in normal cells (p < 0.001). Silica-stimulated monocytes from patients also secreted more IL-1 than those from normal subjects (p < 0.001) in autologous mixed lymphocyte reaction. Twelve patients had an early proliferative response. At day seven, a decreased proliferative response was seen in 12/19 patients (p < 0.001). Skin fibroblasts from 3/3 patients synthesized 3-to-5-fold more 3H-hyaluronic acid than normal control cells (p < 0.001). CONCLUSIONS: This report confirms the association between the injection of modelants and the development of autoimmune disease (human adjuvant disease, HAD). Our results implicate IL-1 in the amplification of the disease process. The similarities between primary scleroderma and human adjuvant disease now include immunological and connective tissue data. The study of these patients may help to understand the etiopathogenesis of some autoimmune diseases.

Reduction of odours in pilot-scale landfill biocovers.

Unpleasant odours generated from waste management facilities represent an environmental and societal concern. This multi-year study documented odour and total reduced sulfur (TRS) abatement in four experimental landfill biocovers installed on the final cover of the Saint-Nicéphore landfill (Canada). Performance was evaluated based on the reduction in odour and TRS concentrations between the raw biogas collected from a dedicated well and the emitted gases at the surface. Odour analyses were carried out by the sensorial technique of olfactometry, whereas TRS analyses followed the pulse fluorescence technique. The large difference of 2-5 orders of magnitude between raw biogas (average odour concentration=2,100,000OUm(-3)) and emitted gases resulted in odour removal efficiencies of close to 100% for all observations. With respect to TRS concentrations, abatement efficiencies were all greater than 95%, with values averaging 21,000ppb of eq. SO2 in the raw biogas. The influence of water infiltration on odour concentrations was documented and showed that lower odour values were obtained when the 48-h accumulated precipitation prior to sampling was higher.

Utilização da técnica in vitro semiautomática de produção de gases na avaliação da fermentação microbiana do ceco de suínos / Use of the semi-automatic in vitro gas production technique for the evaluation of swine cecal microbial fermentation

O presente estudo teve como objetivo avaliar o os padrões de fermentação microbiana do ceco de suínos, utilizando-se um modelo aplicado na técnica in vitro de produção de gases para ruminantes. Três tipos de inóculo foram utilizados: ceco de suínos criados ao ar livre (CSF), ceco de suínos criados confinados (CSC) e líquido ruminal de bovino (LRB). Os substratos utilizados derivaram de uma dieta de suínos à base de farelo de soja e de grãos de milho, atendendo as exigências nutricionais dos suínos. Para composição dos substratos, foram estabelecidos diferentes níveis de substituição da dieta basal pela torta da amêndoa da Acrocomia aculeata (AA), coproduto da produção do biodiesel, sendo: BAS - 100% de dieta basal; M10 - 90% de dieta basal e 10% AA; M20 - 80% de dieta basal e 20% AA e o TF - feno de Tifton 85 (Cynodon spp.). A produção de gases foi avaliada nos tempos zero, três, seis, nove, 12, 16, 24, 48, 72 e 96 horas após a incubação. Foram analisados o potencial máximo de produção de gás (A) e o tempo de colonização (L). O delineamento experimental utilizado foi inteiramente ao acaso, em arranjo fatorial 4 x 3. Os dados de A e L foram submetidos à análise de variância, e as médias comparadas pelo teste de Tukey a 5%. Comparando os inóculos para A (mL/gMS), LRB e CSF apresentaram valores similares, diferindo apenas para TF. O tempo de colonização (L) entre inóculos, o CSC e o CSF apresentaram os menores tempos de colonização quando a ração foi BAS. Com os substratos M10 e M20, o inóculo LRB apresentou o menor tempo, CSF o maior tempo e CSC não diferiu de ambos. Não houve diferença significativa entre os inóculos para o substrato TF. A técnica de produção de gases utilizada para o ceco de suínos apresentou resultados semelhantes aos encontrados para ruminantes. O modelo matemático usado foi adequado para descrever a curva de fermentação no ceco de suínos, mostrando semelhanças entre as microbiotas do ceco e do rúmen.(AU)

This study aimed to evaluate the microbial fermentation patterns of the pig ceca using the technique of in vitro gas production for ruminants. Three types of inoculums were used: swine ceca raised in a free range system (CSF), swine ceca raised in a conventional confined system (CSC) and bovine rumen fluid (LRB). The substrates used were derived from pig's diet with soybean meal and corn grits, according to the nutritional requirements of swine. The substrates were composed by different set levels of substitution of basal diet by meal almond Acrocomia aculeata (AA), as: BAS - 100% of basal diet; M10 - 90% of basal diet and 10% AA (M10); M20 - 80% of basal diet and 20% AA (M20) and TF - Tifton 85 hay (Cynodon spp.).The gas production was evaluated at times 0, 3, 6, 9, 12, 16, 24, 48, 72 and 96 hours after incubation. The study analyzed the maximum potential of gas production (A) and lag time (L). The experimental design was completely randomized in a 4 x 3 factorial arrangement. The A and L data were submitted to analysis of variance and the averages compared by Tukey 5% test. Comparing the inoculum for A (ml / gDM), LRB, and CS, they showed similar values, differing only for TF. The lag time (L) between inoculum, the CSC and CSF had the lowest colonization times when the meal was BAS. With M10 and M20 substrates, the LRB inoculum showed the lowest time, CSF had the longest time and CSC did not differ from both. There was no significant difference between the inoculum for TF substrate. The gas production technique used for the ceca of pigs showed similar results to those for ruminants. The mathematical model used was adequate to describe the fermentation curve in the ceca of pigs, showing similarities between the microbiota of the ceca and the rumen.(AU)