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The meniscus is divided into three zones according to its vascularity: an external vascularized red-red zone mainly comprising collagen I, a red-white interphase zone mainly comprising collagens I and II, and an internal white-white zone rich in collagen II. Known scaffolds used to treat meniscal injuries do not reflect the chemical composition of the vascular areas of the meniscus. Therefore, in this study, four composite zonal scaffolds (named A, B, C, and D) were developed and characterized; the developed scaffolds exhibited the main chemical components of the external (collagen I), interphase (collagens I/II), and internal (collagen II) zones of the meniscus. Noncomposite scaffolds were also produced (named E), which had the same shape as the composite scaffolds but were entirely made of collagen I. The composite zonal scaffolds were prepared using different concentrations of collagen I and the same concentration of collagen II and were either cross-linked with genipin or not cross-linked. Porous, biodegradable, and hydrophilic scaffolds with an expected chemical composition were obtained. Their pore size was smaller than the size reported for the meniscus substitutes; however, all scaffolds allowed the adhesion and proliferation of human adipose-derived stem cells (hADSCs) and were not cytotoxic. Data from enzymatic degradation and hADSC proliferation assays were considered for choosing the cross-linked composite scaffolds along with the collagen I scaffold and to test if composite zonal scaffolds seeded with hADSC and cultured with differentiation medium produced fibrocartilage-like tissue different from that formed in noncomposite scaffolds. After 21 days of culture, hADSCs seeded on composite scaffolds afforded an extracellular matrix with aggrecan, whereas hADSCs seeded on noncomposite collagen I scaffolds formed a matrix-like fibrocartilage without aggrecan.

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We report the case of a 54-year-old immunocompetent woman who presented with a primary T-cell/histiocyte-rich large B-cell lymphoma (TCHRLBCL) of the central nervous system without systemic involvement, diagnosed by means of a brain biopsy. She was treated with corticosteroids and we subsequently started chemotherapy with rituximab, methotrexate, ifosfamide and intrathecal cytarabine. The patient's symptoms gradually improved over the first weeks and we followed-up with autologous haematopoietic cell transplantation. The patient has been in complete remission for a year. Primary TCHRLBCL of the central nervous system in an immunocompetent patient is an extremely rare condition that requires a multidisciplinary approach. This case highlights the importance of undergoing a sequential work-up and establishing a treatment despite the absence of evidence-based guidelines.

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Abstract Primary hyperoxaluria (PH) is a very rare genetic disorder; it is characterized by total or partial deficiency of the enzymes related to the metabolism of glyoxylate, with an overproduction of calcium oxalate that is deposited in different organs, mainly the kidney, leading to recurrent lithiasis, nephrocalcinosis and end stage renal disease (ESRD). In patients with ESRD that receive kidney transplantation alone, the disease has a relapse of 100%, with graft loss in a high percentage of patients in the first 5 years of transplantation. Three molecular disorders have been described in PH: mutation of the gene alanin glioxalate aminotransferase (AGXT); glyoxalate reductase/hydroxy pyruvate reductase (GRHPR) and 4-OH-2-oxoglutarate aldolase (HOGA1). We present two cases of patients with a history of renal lithiasis who were diagnosed with primary hyperoxaluria in the post-transplant period, manifested by early graft failure, with evidence of calcium oxalate crystals in renal biopsy, hyperoxaluria, hyperoxalemia, and genetic test compatible; they were managed with proper diet, abundant oral liquids, pyridoxine, hydrochlorothiazide and potassium citrate; however, they had slow but progressive deterioration of their grafts function until they reached end-stage chronic renal disease.

Resumo A hiperoxalúria primária (HP) é um distúrbio genético muito raro, caracterizado por deficiência total ou parcial das enzimas relacionadas ao metabolismo do glioxilato, superprodução de oxalato de cálcio que se deposita em vários órgãos (principalmente os rins) resultando em litíase recorrente, nefrocalcinose e doença renal terminal (DRT). Nos pacientes com DRT que recebem transplante renal, a doença apresenta recidiva em 100% dos casos, com perda do enxerto nos primeiros cinco anos após o transplante num elevado percentual de pacientes. Três distúrbios moleculares foram descritos na HP: mutação dos genes da alanina-glioxilato aminotransferase (AGXT), glioxilato redutase/hidroxipiruvato redutase (GRHPR) e 4-OH-2-oxoglutarato aldolase (HOGA1). Apresentamos dois casos de pacientes com histórico de litíase renal diagnosticados com hiperoxalúria primária no período pós-transplante, manifestada na forma de perda precoce do enxerto com evidências de cristais de oxalato de cálcio na biópsia renal, hiperoxalúria, hiperoxalemia e testes genéticos compatíveis. Os pacientes foram tratados com abordagem nutricional, líquidos orais em abundância, piridoxina, hidroclorotiazida e citrato de potássio. Contudo, os pacientes apresentaram deterioração lenta e gradual da função do enxerto e evoluíram para doença renal terminal.

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Primary hyperoxaluria (PH) is a very rare genetic disorder; it is characterized by total or partial deficiency of the enzymes related to the metabolism of glyoxylate, with an overproduction of calcium oxalate that is deposited in different organs, mainly the kidney, leading to recurrent lithiasis, nephrocalcinosis and end stage renal disease (ESRD). In patients with ESRD that receive kidney transplantation alone, the disease has a relapse of 100%, with graft loss in a high percentage of patients in the first 5 years of transplantation. Three molecular disorders have been described in PH: mutation of the gene alanin glioxalate aminotransferase (AGXT); glyoxalate reductase/hydroxy pyruvate reductase (GRHPR) and 4-OH-2-oxoglutarate aldolase (HOGA1). We present two cases of patients with a history of renal lithiasis who were diagnosed with primary hyperoxaluria in the post-transplant period, manifested by early graft failure, with evidence of calcium oxalate crystals in renal biopsy, hyperoxaluria, hyperoxalemia, and genetic test compatible; they were managed with proper diet, abundant oral liquids, pyridoxine, hydrochlorothiazide and potassium citrate; however, they had slow but progressive deterioration of their grafts function until they reached end-stage chronic renal disease.

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Light chain-associated kidney compromise is frequent in patients with monoclonal gammopathies; it affects the glomeruli or the tubules, and its most common cause is multiple myeloma. It may develop after a kidney transplant due to recurrence of a preexisting multiple myeloma or it can be a de novo disease manifesting as graft dysfunction and proteinuria. A kidney biopsy is always necessary to confirm the diagnosis.We describe three cases of kidney graft dysfunction due to multiple myeloma in patients without presence of the disease before the transplant.

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La distrofia miotónica es una enfermedad hereditaria del sistema neuromuscular con afección cardiaca, se presenta fundamentalmente con alteraciones del ritmo y conducción auriculoventricular y rara vez insuficiencia cardiaca. Se expone el caso de un paciente de 37 años de edad que ingresa por falla cardiaca aguda y flutter auricular asociado a debilidad muscular progresiva de larga data en quien se realiza diagnóstico de distrofia miotónica tipo 1 luego de estudios complementarios. Se presenta una corta revisión de la literatura acerca de esta enfermedad y sus manifestaciones cardiacas.

Myotonic dystrophy is a hereditary disease of the neuromuscular system with cardiac impairment, mainly showing rhythm disturbances and atrioventricular conduction defects, and rarely heart failure. We report the case of a 37 year-old patient who was admitted for acute heart failure and atrial flutter associated with long standing progressive muscle weakness. A diagnosis of myotonic dystrophy type 1 was made after complementary studies. A short review of the literature about this pathology and the cardiac manifestations is presented.

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La nefropatía asociada a las gammapatías monoclonales es debida principalmente al depósito de cadenas ligeras. Las enfermedades renales paraproteinémicas son lesiones asociadas con depósito de inmunoglobulinas intactas o fragmentos de inmunoglobulinas (cadenas pesadas y cadenas ligeras). La enfermedad por depósito de cadenas ligeras es una condición rara, caracterizada por el depósito de cadenas ligeras monoclonales en muchos órganos y a nivel renal predominantemente en glomérulos y membranas basales tubulares. La enfermedad está frecuentemente asociada con desórdenes linfoproliferativos, y la mayoría de casos son causados por depósito de cadenas ligeras kappa. Aunque se presenta sobre todo en cuadros malignos, en ocasiones no se detecta patología hematológica y se denomina idiopática o "primaria". Suele manifestarse como una insuficiencia renal severa con proteinuria nefrótica, no tiene tratamiento claramente establecido y el pronóstico es malo. Se describen las características clínicas e histológicas del segundo caso informado en Colombia de nefropatía por depósito de cadenas ligeras diagnosticado en el contexto de una enfermedad renal paraproteinémica sin datos de malignidad. (Acta Med Colomb 2014; 39: 196-201).

Nephropathy associated with monoclonal gammopathies is mainly due to light chain deposition. The paraproteinemic kidney diseases are lesions associated with deposition of intact immunoglobulins or fragments of immunoglobulins (heavy and light chains). The disease due to deposition of light chains is a rare condition characterized by deposition of monoclonal light chains in many organs and as for the kidney, predominantly in glomeruli and tubular basement membranes. The disease is frequently associated with lymphoproliferative disorders and the majority of cases are caused by deposition of kappa light chains. Although presented primarily in clinical pictures of malignancy, sometimes no hematological pathology is detected and is called idiopathic or "primary". It usually manifests as severe renal failure with nephrotic proteinuria, has not a clearly established treatment and the prognosis is poor. The clinical and histological features of the second case reported in Colombia of a light chain deposition nephropathy diagnosed in the context of a kidney paraproteinemic disease without malignancy data, is presented. (Acta Med Colomb 2014; 39: 196-201).

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En esta segunda publicación sobre el uso de electrocardiograma de superficie como medio diagnóstico, se discutirán los principales hallazgos sobre las arritmias, específicamente las ubicadas en el plano supraventricular auricular

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En esta tercera publicación sobre el uso del electrocardiograma de superficie como medio diagnóstico, se discutirán los principales hallazgos sobre las arritmias, específicamente las ubicadas en el plano supraventricular nodal y en el plano ventricular

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