[Rapidly progressive crescentic glomerulonephritis in the elderly]. / Glomerulonefritis rápidamente progresiva en ancianos.

Rapidly progressive glomerulonephritis (RPGN) is a syndrome characterized by glomerular lesions giving rise to acute renal injury that develops within a brief period of time, usually days or a few months. It is classified according to the underlying mechanism of injury and the immunofluorescence findings into four main disorders. In the last decade, nephrologists have witnessed a steady rise in the mean age of the patients diagnosed with RPGN. This observation may reflect an increase in the incidence of this entity and also a more timely diagnosis. We present 3 cases of RPGN in elderly patients, diagnosed within a 3 month period at our institution which illustrates the spectrum of these conditions.

N-terminal PAX8 polyclonal antibody shows cross-reactivity with N-terminal region of PAX5 and is responsible for reports of PAX8 positivity in malignant lymphomas.

Recently, reports using immunohistochemistry and a polyclonal antibody directed against the N-terminal region of PAX8 describe PAX8 expression in malignant lymphomas. As the N-terminal regions of PAX family members, including the B-cell transcription factor PAX5, have high sequence homology, we investigated PAX8 positivity in malignant lymphomas. Comparative sequence analysis between the N- and C-terminal regions of PAX8 and PAX5 proteins confirmed homologies of 70% and 39%, respectively. We then compared the results using N-terminal (high homology) and C-terminal (lower homology) anti-PAX8 antibodies to assess PAX8 expression in reactive tissues, diffuse large B-cell lymphoma and classical Hodgkin lymphoma, using routine immunohistochemical methods. Expression of PAX8 was also assessed in diffuse large B-cell lymphoma and classical Hodgkin lymphoma cell lines using real-time qRT-PCR methods. Our results show that reactive and neoplastic B-cells are positive for PAX8 using the N-terminal antibody, but negative for PAX8 when the C-terminal antibody was used. PAX8 mRNA levels were not detected in any of the B-cell lymphoma cell lines studied. These results indicate that benign and malignant B-cells do not express PAX8. We conclude that positivity for PAX8 reported by others in B-cell lymphomas is likely due to cross-reactivity between the N-terminal regions of PAX8 and PAX5, due to the high sequence homology of these two regions.

Severe neutropenia in a renal transplant patient suggesting an interaction between mycophenolate and fenofibrate.

OBJECTIVE: To describe a patient in whom initiation of micronized fenofibrate precipitated mycophenolate induced neutropenia. CASE SUMMARY: A 57-year-old man was admitted to the hospital because of febrile neutropenia. He had undergone kidney transplantation seventeen years ago. The patient's immunosuppressive maintenance regimen consisted of mycophenolate mofetil (MMF) 500 mg three times a day, and meprednisone 4 mg daily. His medical history included, hypertension treated with losartan 50mg daily, and dyslipidemia treated with ezetimibe 10mg /simvastatin 20mg for four years (until 2 weeks before admission when micronized fenofibrate 200 mg per day was started because of persistently elevated triglycerides levels. On presentation temperature was 37.8°C and initial laboratory tests showed 3130 White Blood Cell Count(WBC)/µL with neutropenia (absolute neutrophil count (ANC) 313/µL) Fenofibrate and mycophenolate mofetil were discontinued, piperacillin tazobactam 4.5gr three times a day and granulocyte stimulation factor 300 µg/day were started. Three days after admission WBC was 7280/µL, neutrophils: 22%, ANC: 1160/mm(3). Mycophenolate mofetil was restarted and granulocyte stimulation factor was discontinued. One month after discharge his WBC was 4480/µL and ANC 1926/µL. DISCUSSION: The initiation of fenofibrate in a patient on stable and therapeutic doses of mycophenolate may have precipitated mycophenolate induced neutropenia, a well described, dose dependent phenomenon. Mycophenolic acid (MPA) displays a complex pharmacokinetic profile susceptible to potential significant interactions with fenofibrate. Since approximately 99% of MPA and fenofibrate bind to albumin, displacement may occur, leading to increased free MPA. Second competition of fenofibric acid for UGT1A9 an enzyme implicated in conjugation of MPA may have decreased its metabolism. The combination of these two effects may increase the risk of dose dependent neutropenia. Using the Interaction Probability Scale (DIPS), the interaction was designated as probable. CONCLUSIONS: Until further evidence is available, when fenofibrate is started in a renal transplant patient on mycophenolate careful monitoring should be considered to avoid potentially fatal complications.

Glomerulonefritis rápidamente progresiva en ancianos / Rapidly progressive crescentic glomerulonephritis in the elderly

La glomerulonefritis rápidamente progresiva (GNRP) es un síndrome clínico que se caracteriza por la presencia de signos urinarios de enfermedad glomerular e insuficiencia renal de desarrollo en un lapso de días a pocos meses. La inmunofluorescencia permite clasificar a las GNRP en cuatro tipos según se identifiquen o no depósitos inmunes y, si están presentes, de acuerdo con su naturaleza. En la última década se ha demostrado un aumento constante en el promedio de edad de los pacientes con GNRP. Este fenómeno podría reflejar tanto una mayor incidencia de la enfermedad, como un incremento en la tasa de diagnóstico. Se presentan 3 casos de GNRP en adultos mayores de 65 años, diagnosticados en un periodo de 3 meses en nuestra institución.

Rapidly progressive glomerulonephritis (RPGN) is a syndrome characterized by glomerular lesions giving rise to acute renal injury that develops within a brief period of time, usually days or a few months. It is classified according to the underlying mechanism of injury and the immunofluorescence findings into four main disorders. In the last decade, nephrologists have witnessed a steady rise in the mean age of the patients diagnosed with RPGN. This observation may reflect an increase in the incidence of this entity and also a more timely diagnosis. We present 3 cases of RPGN in elderly patients, diagnosed within a 3-month period at our institution which illustrates the spectrum of these conditions.

Estudio fenotípico de inestabilidad microsatelital en cáncer colorrectal. Correlación con parámetros histológicos y clínicos / Immunohistochemical study of microsatellite instability in colorectal cancer. Correlation with histological and clinical parameters

La detección de proteínas de reparación del ADN por inmunohistoquímica (IHQ) ha demostrado ser útil para determinar inestabilidad de microsatélites (IM). Las guías de Bethesda revisadas y el MsPath Score permiten detectar pacientes de alto riesgo. Se analizaron criterios histológicos sugestivos de IM en 115 pacientes con cáncer colorrectal (CCR). Se efectúo el MsPath Score e IHQ para la demostración de proteínas de reparación del ADN (MMR): MLH1 MSH2, MSH6 y PMS2. La distribución por sexos fue de 66 varones y 49 mujeres, con un rango etario de 16 a 78 años. Cincuenta y tres casos tuvieron rasgos morfológicos de IM: linfocitos intraepiteliales (n = 31), infiltrados tipo Crohn (n = 17), morfología mucinosa/células en anillo de sello (n = 32) y/o pobre diferenciación (n = 12) en forma simultánea o aisladamente. Se observó patrón aberrante para MMR en 16 casos: ausencia de expresión de MLH1/PMS2 (n = 11), MSH2/MSH6 (n = 3), MLH1 (n = 1) y PMS2 (n = 1). Los adenocarcinomas con rasgos morfológicos convencionales no mostraron alteraciones en las MMR (n = 62) (AU)

The detection of mismatch repair proteins (MMR) by immunohistochemistry (IHC) is a useful tool in the identification of microsatellital inestability (MI). The revised Bethesda guidelines and MsPath score allow the detection of patients at high-risk for MI. We studied 115 patients with colorectal cancer (CRC) and evaluated the histological criteria of MI. Detection of MMR: MLH1, MSH2, MSH6 and PMS2 were analyzed by IHC. Sixty-six male and 49 female patients (age range 16-78). Histological picture of MI was observed in 53 cases: intraepithelial lymphocytosis (n = 31), Crohn like infiltrates (n = 17), mucinous or ringed cell histology (n = 32) and/or poorly differentiated histology (n = 12). Aberrant immunostaining pattern of MMR was observed in 16 cases: negative MLH1/PMS2 (n = 11), negative MSH2/MSH6 (n = 3), negative MLH1 (n = 1) and negative PMS2 (n = 1). The 62 cases with conventional histology had normal immunostaining. Conventional histology (n = 62) did not show any alterations in MMR (AU)