Searching for a prognostic index in lupus nephritis.

BACKGROUND: Currently we do not have an ideal biomarker in lupus nephritis (LN) that should help us to identify those patients with SLE at risk of developing LN or to determine those patients at risk of renal progression. We aimed to evaluate the development of a prognostic index for LN, through the evaluation of clinical, analytical and histological factors used in a cohort of lupus. We have proposed to determine which factors, 6 months after the diagnosis of LN, could help us to define which patients will have a worse evolution of the disease and may be, more aggressive treatment and closer follow-up. METHODS: A retrospective study to identify prognostic factors was carried out. We have included patients over 18 years of age with a clinical diagnosis of systemic lupus erythematosus (SLE) and kidney involvement confirmed by biopsy, who are followed up in our centre during the last 20 years. A multi-step statistical approach will be used in order to obtain a limited set of parameters, optimally selected and weighted, that show a satisfactory ability to discriminate between patients with different levels of prognosis. RESULTS: We analysed 92 patients with LN, although only 73 have been able to be classified according to whether or not they have presented poor renal evolution. The age of onset (44 vs. 32; p = 0.024), the value of serum creatinine (1.41 vs. 1.04; p = 0.041), greater frequency of thrombocytopenia (30 vs. 7%; p = 0.038), higher score in the renal chronicity index (2.47 vs. 1.04; p = 0.015), proliferative histological type (100%) and higher frequency of interstitial fibrosis (67 vs. 32%; p = 0.017) and tubular atrophy (67 vs. 32%; p = 0.018) was observed between two groups. The multivariate analysis allowed us to select the best predictive model for poor outcome at 6 months based on different adjustment and discrimination parameters. CONCLUSION: We have developed a prognostic index of poor renal evolution in patients with LN that combines demographic, clinical, analytical and histopathological factors, easy to use in routine clinical practice and that could be an effective tool in the early detection and management.

Distribution patterns, carbon sources and niche partitioning in cave shrimps (Atyidae: Typhlatya).

Cave shrimps of the Typhlatya genus are common and widespread in fresh, brackish and marine groundwater throughout the Yucatan Peninsula (Mexico). These species are ideal models to test niche partitioning within sympatric species in oligotrophic systems. Nevertheless, their food sources remain unidentified, and despite their frequency and functional importance, distribution and abundance patterns of these species within caves have not been fully recognized. Here, we describe the abundance of three Typhlatya species in different temporal and spatial scales, investigate changes in water conditions, and potential sources of carbon as an indication of food origin. Species composition and abundance varied markedly in space and time revealing patterns that differed from one system to another and in relation to environmental parameters. Isotope analysis showed that each species reflects a particular δ13C and Δ14C fingerprint, suggesting they feed in different proportions from the available carbon sources. Overall, our findings suggest a niche partitioning of habitat and feeding sources amongst the three Typhlatya species investigated, where environmental characteristics and physiological differences could play an important role governing their distribution patterns.

FAK phosphorylation plays a central role in thrombin-induced RPE cell migration.

The migration of retinal pigment epithelial (RPE) cells is an important step in various pathologic conditions including subretinal neovascularization (SRN), proliferative vitreoretinopathy (PVR) and, importantly, as a consequence of retinal surgery. Therefore, the elucidation of the mechanisms underlying RPE trans-differentiation and migration is essential for devising effective treatments aimed to the prevention of these disorders. A common event in these pathologies is the alteration of the blood-retina barrier (BRB), which allows the interaction of RPE cells with thrombin, a pro-inflammatory protease contained in serum. Our previous work has demonstrated that thrombin induces RPE cell cytoskeletal remodeling and migration, hallmark processes in the development of PVR; however, the molecular mechanisms involved are still unclear. Cell migration requires the disassembly of focal adhesions induced by Focal Adhesion Kinase (FAK) phosphorylation, together with the formation of actin stress fibers. The aim of the present work was to identify thrombin-activated signaling pathways leading to FAK phosphorylation and to determine FAK participation in thrombin-induced RPE cell migration. Results demonstrate that the activation of PAR1 by thrombin induces FAK autophosphorylation at Y397 and the subsequent phosphorylation of Y576/577 within the activation loop. FAK phosphorylation was shown to be under the control of c/nPKC and PI3K/PKC-ζ, as well as by Rho/ROCK, since the inhibition of these pathways prevented thrombin-induced FAK phosphorylation and the consequent disassembly of focal adhesions, in parallel to FAK-dependent actin stress fiber formation and RPE cell migration. These findings demonstrate, for the first time, that thrombin stimulation of RPE cell transformation and migration are regulated by FAK tyrosine phosphorylation. Thus, targeting FAK phosphorylation may provide a strategical basis for PVR treatment.

Inflamación y síndrome metabólico por resistencia a la insulina-leptina en pacientes con psoriasis / Inflammation and metabolic syndrome due to insulin-leptin resistance in psoriatic patients

Resumen La psoriasis es una enfermedad inflamatoria crónica que se distingue por hiperproliferación recidivante de la piel, de causa y patogénesis multifactoriales. Afecta aproximadamente a 1-3% de la población en general. Durante los últimos diez años, en diversos estudios se ha encontrado que los pacientes con psoriasis tienen prevalencia elevada de factores de riesgo cardiovascular. Asimismo, esos estudios también sugieren una relación entre el síndrome metabólico y la psoriasis. El síndrome metabólico comprende una serie de condiciones fisiopatológicas relacionadas principalmente con aspectos metabólicos, como la resistencia y señalización a la insulina y leptina (Sx Met_RI-Lep). Es un grupo de factores de riesgo que incluye obesidad central, dislipidemia aterogénica, hipertensión arterial sistémica e intolerancia a la glucosa. Su importancia se debe a que duplica el riesgo de enfermedad cardiovascular y diabetes mellitus tipo 2, y aumenta la mortalidad incluso más que sus componentes por separado. La prevalencia mundial del síndrome varía en función del país y de los criterios utilizados para medirla; varía entre 15 y 47% de la población general. Las prevalencias publicadas también varían de acuerdo con las organizaciones que las emiten; tal es el caso de los criterios de la Organización Mundial de la Salud (OMS), que indican que la prevalencia en México es de 14%, y al aplicar los criterios ATP-III asciende a 27%. Existen, por tanto, 6.7 y 14.3 millones de mexicanos afectados, según los criterios de la Organización Mundial de la Salud y los ATP-III, respectivamente. La asociación de la psoriasis con otras enfermedades sistémicas podría deberse a diversas causas, como predisposición genética, factores ambientales (tabaco, alcohol, vida sedentaria) o tratamientos sistémicos prescritos. Cada vez son más los estudios que relacionan el síndrome metabólico por resistencia a la insulina-leptina con la psoriasis. En esta revisión bibliográfica se pretende sintetizar los mecanismos fisiopatológicos compartidos por ambos padecimientos, así como insistir en el cribado de los factores de riesgo cardiovasculares y del síndrome metabólico para prevenir o mejorar el tratamiento y pronóstico de los pacientes con psoriasis.

Abstract Psoriasis is a chronic inflammatory disease characterized by relapsing skin hyperproliferation, with multifactorial pathogenesis and causes. It affects approximately 1% to 3% of the general population. During the past ten years, several studies have found that patients with psoriasis have a high prevalence of cardiovascular risk factors. Likewise, such studies also suggest a link between metabolic syndrome and psoriasis. Metabolic syndrome comprises a number of pathophysiologic conditions that mainly involves the metabolic aspects concerning insulin-leptin resistance and signaling (Sx Met_RI-Lep). It is a group of risk factors including central obesity, atherogenic dyslipidemia, systemic hypertension and glucose intolerance. Its importance is due to its presence doubles the risk of cardiovascular disease, type 2 diabetes mellitus and increases mortality higher than its separate components. The worldwide prevalence of the syndrome varies depending on the country and the criteria used; between 15% and 47% of the general population. The prevalence published also vary according to the organizations that issue; such is the case of the criteria of the World Health Organization (WHO) to handle a prevalence in Mexico of 14% and applying the criteria ATP-III rises to 27%, so there are 6.7 and 14.3 million Mexicans affected, according to the criteria of the World Health Organization and the ATP-III, respectively. The association of psoriasis with other systemic diseases may be due to various causes such as genetic predisposition, environmental factors (smoking, alcohol, sedentary lifestyle) or be influenced by systemic treatments used against psoriasis. More and more studies link the Sx Met_RI-Lep with psoriasis. This paper summarizes the pathophysiological mechanisms shared by both pathologies, as well as emphasizes screening for cardiovascular risk factors and metabolic syndrome to improve treatment and prognosis of psoriasis.

Extended-release tacrolimus therapy in de novo kidney transplant recipients: single-center experience.

BACKGROUND: Available data for extended-release tacrolimus (Tac) except in clinical trials are limited. OBJECTIVE: To describe our initial experience with once-daily Tac in combination with corticosteroids and mycophenolate mofetil therapy in patients undergoing de novo renal transplantation. PATIENTS AND METHODS: In this retrospective, observational, single-center study, data were obtained for 49 adult recipients treated with extended-release Tac and 30 patients treated with standard-release Tac (control group). Mean (SD) follow-up in the 2 groups was 3.5 (2.5) months and 4.0 (2.6) months, respectively. The primary characteristics were comparable between the groups. RESULTS: The acute rejection rate in the extended-release group was 10%, and 13% in the standard-release group. Patient and graft survival rates were 98% and 96% vs 100% and 90%, respectively. Renal function in the 2 groups was comparable: serum creatinine concentration 1.3 (0.2) mg/dL vs 1.45 (0.4) mg/dL. At day 14 posttransplantation, Tac doses were 0.17 mg/kg/d vs 0.14 mg/kg/d, and blood concentrations were 9.0 ng/mL vs 14.0 ng/mL. In recipients older than 60 years, lower dosages of Tac resulted in blood concentrations similar to those in younger patients, with less variation in dosage. CONCLUSIONS: Short-term experience with extended-release Tac therapy in de novo renal recipients confirms its efficacy and safety. Adjusting blood concentrations in the immediate posttransplantation period is less difficult with extended-release Tac compared with the twice-daily formulation.

[The antiproteinuric effect of the blockage of the renin-angiotensin-aldosterone system (RAAS) in obese patients. Which treatment option is the most effective? ]. / Efecto antiproteinúrico del bloqueo del sistema renina-angiotensina-aldosterona (SRAA) en los pacientes obesos. ¿Cuál es la opción terapéutica más eficaz?

BACKGROUND: Obesity increases the risk of proteinuria and chronic renal insufficiency and hastens the progression of renal diseases. Increased activity of renin-angiotensin-aldosterone system and elevated levels of aldosterone are common in obese patients. No studies have compared the efficacy of the currently available antiproteinuric strategies (ACE inhibitors -ACEI-, angiotensin receptor blockers -ARB-, aldosterone antagonists) in obese patients with proteinuric renal diseases. METHODS: Single centre, prospective, randomized study. Twelve obese patients (body mass index > 30 Kg/m2) with proteinuria > 0.5 g/24 h were selected from our outpatient renal clinic. Patients were consecutively treated during 6 weeks with an ACEI (lisinopril 20 mg/day), combined therapy ACEI+ARB (lisinopril 10 mg/day + candesartan 16 mg/day) and eplerenone (25 mg/day) in random order. A drug washout period of 6 weeks was established between the different treatment periods. The primary outcome point was the change in 24-h proteinuria at the end of each treatment period and the number of patients showing a proteinuria reduction greater than 25% of baseline. RESULTS: The reduction in proteinuria induced by lisinopril (11.3+/-34.8%) was not statistically significant with respect to baseline, whereas that of lisinopril plus candesartan (26.9+/-30.6%) and eplerenone (28.4+/-31.6%) showed a statistically significant difference both with respect to baseline values and to lisinopril group. The number of patients who showed a greater than 25% proteinuria reduction was significantly higher with eplerenone (67%) and lisinopril+candesartan (67%) than with lisinopril (25%). CONCLUSIONS: Monotherapy with an aldosterone antagonist and combination therapy with ACEI+ARB were more effective than ACEI monotherapy to reduce proteinuria in obese patients with proteinuric renal diseases.

Human platelet-specific antigens frequencies in the Argentinean population.

The frequencies of several human platelet antigens (HPAs) vary between different populations and are a major determinant for the prevalence of HPA alloimmunization and its clinical associated entities. The aim of this study was to characterize the allele frequencies of seven HPA systems in two different ethnic groups from the Argentinean city of Rosario, the major population and a minority Amerindian group recently arrived from the north of the country, the Tobas. A total of 192 healthy unrelated individuals from blood donors and hospital staff from the Hospital Italiano Garibaldi and 27 unrelated Toba Amerindians were genotyped for HPA-1, -2, -3, -4, -5, -6 and -15 systems by polymerase chain reaction with sequence specific primers (PCR-SSP). The present data showed that the distribution of the HPA alleles among Argentineans from Rosario is quite similar to that reported among Europeans. The frequencies seen in Tobas, although limited by the small number of aboriginal samples studied, are similar to those reported for other Amerindians populations. Statistically significant differences were found for the genotype distribution of HPA-1, -3, -5 and -15 between both groups, indicating important differences in the potential risk of HPA alloimmunization associated to transfusion and pregnancy. The study of these polymorphisms represents the first step in the elucidation of pathological conditions that are underdiagnosed in our population. It allowed us to establish a panel of characterized blood donors necessary for the serological work out and as a source for compatible platelets transfusion.

HNA-1a, HNA-1b and HNA-1c gene frequencies in Argentineans.

Human neutrophil antigens (HNA) are polymorphic structures located in the neutrophil membrane. The neutrophil-specific antigens HNA-1a (NA1), 1b (NA2) and 1c (SH) are well-recognized allotypic forms of FcgammaRIIIb and the most frequent targets of neutrophil alloantibodies. The aim of this study was to determine the gene frequencies of the neutrophil-specific antigens belonging to the HNA-1 system in blood donors and Toba Amerindians from Rosario, Argentina. Two hundred and eighteen unrelated healthy Argentinean blood donors and Toba Amerindians from Rosario were typed for HNA-1a, HNA-1b and HNA-1c using polymerase chain reaction with sequence-specific primers. For the Argentinean blood donors, the HNA-1a and HNA-1b gene frequencies were 0.44 and 0.56 and for the Amerindians Toba were 0.77 and 0.23, respectively. The HNA-1c antigen is present in 4.7% (gene frequency=0.023) of the blood donors but in none of the Amerindian individuals. The present data showed that the HNA-1 allele frequencies in the major population and the Toba Amerindians from Rosario are similar to those described in European and others distant Amerindians populations, respectively.

The molecular genetics of Marfan syndrome and related disorders.

Marfan syndrome (MFS), a relatively common autosomal dominant hereditary disorder of connective tissue with prominent manifestations in the skeletal, ocular, and cardiovascular systems, is caused by mutations in the gene for fibrillin-1 (FBN1). The leading cause of premature death in untreated individuals with MFS is acute aortic dissection, which often follows a period of progressive dilatation of the ascending aorta. Recent research on the molecular physiology of fibrillin and the pathophysiology of MFS and related disorders has changed our understanding of this disorder by demonstrating changes in growth factor signalling and in matrix-cell interactions. The purpose of this review is to provide a comprehensive overview of recent advances in the molecular biology of fibrillin and fibrillin-rich microfibrils. Mutations in FBN1 and other genes found in MFS and related disorders will be discussed, and novel concepts concerning the complex and multiple mechanisms of the pathogenesis of MFS will be explained.

[Tansitional vesical cell carcinoma metastatizing to the sphenoid sinus]. / Metástasis esfenoidal de un carcinoma de células trancisionales de la vejiga.

Secundary tumors of the paranasal sinus are very uncommon with only one hundred cases reported in the literature up to 2001. The commonest site of the primary tumor is the kidney. The maxillary sinus is most often involved. The Sphenoid sinus is the rarest site. We report a rare case of metastasis to the sphenoid sinces from a transitional cell bladder tumor in a 69-year-old man who died after treatment with chemotherapy and we also review the liteature.

[Effect of short-term nonsteroidal antiinflammatory therapy on mean blood pressure. A prospective, randomized clinical trial]. / Efecto del tratamiento a corto plazo con antiinflamatorios no esteroideos en la presión arterial media. Un ensayo clínico aleatorizado.

Our objective was to evaluate the effect of short-term therapy with nonsteroidal antiinflammatory drugs (NSAID) on mean blood pressure (MBP). Two hundred thirty-three consecutive patients (185 women, 54 men; 53.9±13.5 years) requiring NSAID therapy were prospectively randomized to: indomethacin (21 patients), naproxen (33 patients), diclofenac (40 patients), sulindac (42 patients), meloxicam (35 patients) and celecoxib (40 patients) for 8.5±2 days. BP was measured at the beginning and end of follow-up using a Kenz OS22 monitor. At the end of follow-up, 211 (88%) patients were still available for evaluation. A slight posttreatment decrease in MBP (-1.4±9.0 mm Hg, 95%CI: -2.7 to -0.2) was found. No significant differences in posttreatment changes in MBP were found among the distinct NSAIDs evaluated. Fifty-five patients (23%; 95% CI: 18-29) showed a posttreatment increase in MBP of>5 mm Hg. This increase was not associated with hypertension, old age, or any specific NSAID. We conclude that, overall, shortterm NSAID therapy does not seem to have a clinically significant effect on MAP. However, 23% of patients undergoing this therapy showed an increase in MBP that, if persistent, could lead to a higher risk of cardiovascular disease. Further research is needed to identify whether this outcome persists in long-term NSAID therapy.

Development of a genome-wide anchored microsatellite map for common bean (Phaseolus vulgaris L.).

A total of 150 microsatellite markers developed for common bean ( Phaseolus vulgaris L.) were tested for parental polymorphism and used to determine the positions of 100 genetic loci on an integrated genetic map of the species. The value of these single-copy markers was evident in their ability to link two existing RFLP-based genetic maps with a base map developed for the Mesoamerican x Andean population, DOR364 x G19833. Two types of microsatellites were mapped, based respectively on gene-coding and anonymous genomic-sequences. Gene-based microsatellites proved to be less polymorphic (46.3%) than anonymous genomic microsatellites (64.3%) between the parents of two inter-genepool crosses. The majority of the microsatellites produced single bands and detected single loci, however four of the gene-based and three of the genomic microsatellites produced consistent double or multiple banding patterns and detected more than one locus. Microsatellite loci were found on each of the 11 chromosomes of common bean, the number per chromosome ranging from 5 to 17 with an average of ten microsatellites each. Total map length for the base map was 1,720 cM and the average chromosome length was 156.4 cM, with an average distance between microsatellite loci of 19.5 cM. The development of new microsatellites from sequences in the Genbank database and the implication of these results for genetic mapping, quantitative trait locus analysis and marker-assisted selection in common bean are described.

The possible macrophage role in seminal fluid.

The present report was designed to study the macrophage role and their association with percentage of spermatozoa showing DNA native, morphologically normal sperm and occurrence of antibody-coated spermatozoa. Human sperm samples from 31 patients were used in this study. All samples were evaluated for standard semen parameters according to World Health Organization criteria. The sperm heads with abnormal versus normal chromatin structure were specified as orange-red versus green by Acridine Orange method. Macrophage concentration was assessed with Neutral Red in Neubauer hemocytometer. The technique for the determination of sperm bound antisperm antibodies was sperm mixed antiglobulin reaction. In our study the presence of antisperm antibodies in associated to macrophages concentration (p < 0.05). The log of phagocytic cells were highly correlated with an increase of spermatozoa showing DNA denaturation (p < 0.05). The log of phagocytic cells were highly correlated with an increase of spermatozoa showing DNA denaturation (p < 0.05). There isn't significative association between the log macrophage concentration and morphologically normal sperm (p: 0.414). Thus, the present study further emphasizes the importance of immunosurveillance of the macrophages, and the contribution at the semen quality for the success of the fertilization.

Lamellar bodies as a diagnostic test of fetal lung maturity.

OBJECTIVES: To determine the number of lamellar bodies in the amniotic fluid indicating fetal lung maturity and to define the effectiveness of a diagnostic test in a healthy pregnant population. METHODS: The study took place at the Hospital General de Zona #16 Centro Médico Nacional del Instituto Mexicano del Seguro Social. Torreón, Coahuila, México, where 264 pregnant women were followed-up from August 1997 to October 1998. The women presented in labor between 26 and 41 weeks of gestation. Amniotic fluid was obtained during cesarean section or from the vaginal pool and lamellar bodies were counted without prior centrifugation in Cell-Dyn 3000's channel for blood platelets. Results were masked for neonatologists. RESULTS: The prevalence of respiratory distress syndrome (RDS) was found to be 14.9%. At the 8200/microl threshold, sensitivity was: 15.4% (95% CI=5.9-30.5%), specificity: 99.6% (95% CI=97.5-99.9%), positive predictive value (PPV): 85.7, negative predictive value (NPV): 87.1, likelihood ratio for a negative test (LR-): 0.85, and likelihood ratio for a positive test (LR+): 85.7. At the 57 000/microl level, sensitivity was: 92.3% (95% CI=79.1-98.3%), specificity: 70.9% (64.4-76.7%), PPV: 35.6, NPV: 98.1, LR-: 0.11, and LR+: 3.17. When the cut-off point was 79000/microl, sensitivity was: 100.0%, specificity: 43.0% (95% CI=36.5-49.8%), PPV: 23.5, NPV: 100.0, LR+: 34.3, and LR-: less than 0.001. CONCLUSIONS: Counting lamellar bodies is a quick, readily available, and very effective test.

[Correlation between ABH glycolipids in sperm and functional test]. / Correlación entre glicolipidos ABH en espermatozoides y test funcionales.

OBJECTIVE: To determine the association, if any, between the human spermatic membrane integrity test and normal or altered membrane ABH glycosphingolipids expression. METHODS: Semen samples from 50 patients who consulted at the infertility services of the Provincial del Centenario and Eva Peron de Granadero Belgorria teaching hospitals in Rosario (Argentina) were collected and analyzed in accordance with WHO guidelines. The percentage of dead sperm was analyzed by the eosin test while the percentage of swollen sperm was analyzed by the hypoosmotic test. They were classified according to their ABH expression, either diminished or absent (group 1) or normal (group 2), by applying the hemagglutination inhibition and specific antibody consumption technique. For the statistical analysis the two groups were compared with both spermatic viability tests using the non parametric Mann-Whitney technique for independent samples, since the assumptions for the application of the parametric test (test t) were not fulfilled. RESULTS: A significant difference was found in the percentage of dead sperm (eosin test) of both groups (p < 0.001). However, there was no significant difference in the percentage of swollen sperm (hypoosmotic test) of the two groups. CONCLUSIONS: Our results and the data published in the literature indicate a relationship between a reduced ABH expression and spermatozoid membrane integrity, especially at the level of the head, which leads us to consider that ABH glycosphingolipids are mainly located in this segment of the human spermatozoon involved in the spermatozoon-ovum interactions.

Regulation of limb patterning by extracellular microfibrils.

To elucidate the contribution of the extracellular microfibril-elastic fiber network to vertebrate organogenesis, we generated fibrillin 2 (Fbn2)-null mice by gene targeting and identified a limb-patterning defect in the form of bilateral syndactyly. Digit fusion involves both soft and hard tissues, and is associated with reduced apoptosis at affected sites. Two lines of evidence suggest that syndactily is primarily due to defective mesenchyme differentiation, rather than reduced apoptosis of interdigital tissue. First, fusion occurs before appearance of interdigital cell death; second, interdigital tissues having incomplete separation fail to respond to apoptotic clues from implanted BMP-4 beads. Syndactyly is associated with a disorganized matrix, but with normal BMP gene expression. On the other hand, mice double heterozygous for null Fbn2 and Bmp7 alleles display the combined digit phenotype of both nullizygotes. Together, these results imply functional interaction between Fbn2-rich microfibrils and BMP-7 signaling. As such, they uncover an unexpected relationship between the insoluble matrix and soluble factors during limb patterning. We also demonstrate that the Fbn2- null mutation is allelic to the recessive shaker-with-syndactyly (sy) locus on chromosome 18.

Effectiveness of terbinafine in the eradication of Microsporum canis from laboratory cats.

In this study, the coats of 20 cats with no dermatophytosis lesions were sampled for colonization by Microsporum canis, which was isolated in 45% of cases. All cats were treated with oral terbinafine for 3 weeks. The drug was administered orally at a daily dosage 8.25 mg kg-1. Mycologic status was assessed at the end of the treatment; and after follow-up at 2 days, and 4 and 9 weeks. The final evaluation revealed a complete mycologic cure of all cats by obtaining negative cultures, thereby demonstrating that terbinafine is an effective method of eradication of dermatophyte colonization.

[Typing of colorectal epithelium by lectin histochemistry: expression of T glycoepitope]. / Tipificación del epitelio colorrectal por lectinhistoquímica: expresión del glicotope T.

The current study deals with the setting up of a new tool that enables the benign versus the malignant nature of colorectal epithelium to be determined early and accurately. The objective is to determine a different biologic characteristic between normal and malignant colorectal tissue, which is the site and the level of expression of the T glycoepitope (Thomsen-Friedenreich antigen). It was characterized in a series of 62 colorectal samples, including 31 normal (without pathologic lesion) and 31 cancerous (mostly moderately or poorly differentiated) tissue sections. The glycoconjugate expression was demonstrated by lectin-histochemistry, using PNA lectin. The binding patterns of the lectin were determined in both columnar and goblet cells, from normal and malignant colorectal tissue. The results show that specific and different glycochemical staining patterns could be identified between benign and malignant epithelium. The data of the cytostructural localization were submitted to statistical analyses, which strongly suggested the association between the patterns of expression of the T antigen and the degree of the tissue differentiation. The methodology developed can be applied directly in routine diagnosis and it has an important prognostic value.