Rafael De Armas | Universidad de la República (Uruguay) (original) (raw)

Papers by Rafael De Armas

Clinical Biochemistry, Jul 1, 2010

Gliomas are tumors of the central nervous system derived from glial cells. They show cellular het... more Gliomas are tumors of the central nervous system derived from glial cells. They show cellular heterogeneity and lack specific diagnostic markers. Although a possible role for the eicosanoid cascade has been suggested in glioma tumorigenesis, the relationship between enzymes and receptors implicated in arachidonic acid metabolism, with histological tumor type has not yet been determined. Quantitative real-time reverse transcription-polymerase chain reaction was performed to measure and compare transcript levels of enzymes and receptors implicated in both lipoxygenase and cyclooxygenase pathways between oligodendrogliomas, astrocytomas, glioblastomas and mixed oligoastrocytomas. Arachidonic acid metabolism-related enzymes and receptor transcripts (i) were underexpressed in classical oligodendrogliomas compared to astrocytomas and/or glioblastomas, (ii) differed between astrocytomas and glioblastomas and (iii) had an intermediate expression in mixed oligoastrocytomas. mRNA levels of enzymes and receptors implicated both in lipoxygenase and cyclooxygenase pathways differed significantly in gliomas according to the histological type.

Journal of Cancer Science & Therapy, 2010

In view of the important oncogenic action of lipoxygenase (LOX) and cycloxygenase (COX) enzymatic... more In view of the important oncogenic action of lipoxygenase (LOX) and cycloxygenase (COX) enzymatic activities we investigated, by using real time PCR, their presence in human meningiomas. Results indicated the presence of 5-LOX, 12-LOX, 15-LOX1, 15-LOX2, COX-1, COX-2, prostaglandin E (PGE) synthase, prostacyclin (PGI) synthase and thromboxane (TX) synthase transcripts in meningiomas but without relation to the tumor grade, the subtype of meningiomas, the presence of inflammatory infiltrated cells, of an associated edema, mitosis, brain invasion, vascularisation or necrosis. Similar results were found for BLT1 and BLT2 transcripts (encoding LTB4 receptors) and for prostanoid receptor transcripts (EP 1-4 for PGE 2 , IP for PGI 2 and TP for TXA 2). In conclusion, genes encoding enzymatic activities implicated in the eicosanoid cascade are expressed in meningiomas. LOX-and COX-derived arachidonic acid metabolites might act on tumor growth not only by acting on cell growth but also by altering the local cytokine and/ or angiogenic networks.

Acta Neuropathologica, Jul 9, 2004

We report the case of an 11-year-old male who developed subacute diffuse polyradiculoneuropathy, ... more We report the case of an 11-year-old male who developed subacute diffuse polyradiculoneuropathy, associated with digestive symptoms and Epstein-Barr virus infection. Parental consanguinity was present. The laboratory findings including bone marrow smear were consistent with hemophagocytic lymphohistiocytosis (HLH). Electrophysiological study of peripheral nerves revealed an intense and diffuse demyelinating process. The histological nerve lesions were severe and purely demyelinating. Most axons were intact. There was a diffuse infiltration of the nerve parenchyma by mononuclear cells. Immuno-electron microscopic study evidenced entry of macrophages into Schwann cell cytoplasm with dissociation of myelin sheaths. This boy died several months after the onset of the neuropathic symptoms. HLH is a rare genetic or acquired disorder in childhood characterized by abnormal immune activation, which induces an uncontrolled inflammatory response with sustained hyperactivation of T lymphocytes and macrophages. Only very rare cases of peripheral nerve involvement have been described in HLH. This is the first case showing that peripheral nerves, as other viscera, may be destroyed by the macrophagic infiltration, which characterizes HLH.

American journal of biomedicine, Jan 3, 2020

Glioblastoma is the most common and malignant primary brain tumor but its occurrence in the cereb... more Glioblastoma is the most common and malignant primary brain tumor but its occurrence in the cerebellum is very rare. Giving its low occurrence the treatment modalities and outcome of this glioblastoma location are still poorly understood. We present the case of an adult woman with a cerebellar glioblastoma treated at the Clinical Hospital of Montevideo, and we perform a non-systematic review of the literature concerning the clinical, radiological and pathological features of this tumor, as well as its treatment modalities, prognostic factors and outcome.

Neuropathology and Applied Neurobiology, Dec 1, 2006

Meningiomas are common primary intracranial tumours. Platelet‐activating factor (PAF) is an infla... more Meningiomas are common primary intracranial tumours. Platelet‐activating factor (PAF) is an inflammatory and angiogenic lipid mediator involved in several types of cancer. The presence of PAF receptor (PAF‐R) transcripts, the levels of PAF, the phospholipase A2 activity (PLA2, the enzymatic activity implicated in PAF formation) and the PAF acetylhydrolase activity (AHA, the PAF degrading enzyme) were investigated in 49 human meningiomas. PAF‐R transcripts, PAF, PLA2 and AHA were detected in meningiomas. However, their levels did not correlate with biological parameters such as the tumour grade, the presence of associated oedema, necrosis, mitotic index as well as intensity of the neovascularization and chronic inflammatory response. In conclusion, PAF is present in meningiomas where it might act on tumour growth by altering the local angiogenic and/or cytokine networks as previously suggested for human breast and colorectal cancer.

Mediators of Inflammation, 2009

Mediators of Inflammation, 2006

The quantitative analysis of VEGF using ELISA in various subtypes of grade I meningiomas reported... more The quantitative analysis of VEGF using ELISA in various subtypes of grade I meningiomas reported higher VEGF contents in meningothelial (2.38 ± 0.62 pg/µg protein, n = 7), transitional (1.08 ± 0.21 pg/µg protein, n = 13), and microcystic meningiomas (1.98 ± 0.87 pg/µg protein, n = 5) as compared with fibrous ones (0.36 ± 0.09 pg/µg protein, n = 5). In contrast to VEGF, no difference in the concentrations of bFGF was detected. VEGF levels did not correlate with meningioma grade (1.47 ± 0.23 pg/µg versus 2.29 ± 0.58 pg/µg for 32 and 16 grade I and II, resp), vascularisation (1.53 ± 0.41 pg/µg versus 1.96 ± 0.28 pg/µg for 24 low and 24 high vascularisated tumours, resp), and brain invasion (2.32±0.59 pg/µg versus 1.46±0.27 pg/µg for 7 and 41 patients with and without invasion, resp). The ELISA procedure is, thus, an interesting tool to ensure VEGF and bFGF levels in meningiomas and to test putative correlations with clinical parameters. It is, thus, tempting to speculate that ELISA would also be valuable for the quantitative analysis of other angiogenic growth factors and cytokines in intracranial tumours.

Neurocirugía, May 1, 2020

Peripheral nerve tumours (PNT) are rare lesions that are generally categorised as soft tissue tum... more Peripheral nerve tumours (PNT) are rare lesions that are generally categorised as soft tissue tumours, so they are usually managed by a range of surgical disciplines such as plastic, orthopaedic and trauma surgery, dermatology, general surgery and neurosurgery. Appropriate knowledge of the therapeutic indication and surgical management are essential in order to avoid neurological deficit. This is a retrospective study of 66 tumour lesions in 64 patients, acquired from the joint experience of 2surgical teams specialised in peripheral nerve surgery. The most common location was the lower limb and upper limb with 48 tumour lesions. The most common pathological diagnosis was Schwannoma, accounting for 51.5%. Complete tumour resection was achieved in 81.8% of the lesions and always with neurophysiological stimulation and/or monitoring. The most common postsurgical complication was neuropathic pain and/or a transient sensory disorder in 15% of surgeries, with only one persistent motor deficit appearing in 2cases that required nerve graft reconstruction. Although the therapeutic management of benign tumours such as Schwannomas can be considered to be relatively simple thanks to the application of the basic concepts of peripheral nerve microsurgery, malignant tumors, despite being very rare, require multidisciplinary management. The option of pre-surgical biopsy remains a controversial issue and no consensus has been reached among the different authors. In our opinion, percutaneous biopsy is not necessary in most cases.

Acta Neuropathologica, 2004

We report the case of an 11-year-old male who developed subacute diffuse polyradiculoneuropathy, ... more We report the case of an 11-year-old male who developed subacute diffuse polyradiculoneuropathy, associated with digestive symptoms and Epstein-Barr virus infection. Parental consanguinity was present. The laboratory findings including bone marrow smear were consistent with hemophagocytic lymphohistiocytosis (HLH). Electrophysiological study of peripheral nerves revealed an intense and diffuse demyelinating process. The histological nerve lesions were severe and purely demyelinating. Most axons were intact. There was a diffuse infiltration of the nerve parenchyma by mononuclear cells. Immuno-electron microscopic study evidenced entry of macrophages into Schwann cell cytoplasm with dissociation of myelin sheaths. This boy died several months after the onset of the neuropathic symptoms. HLH is a rare genetic or acquired disorder in childhood characterized by abnormal immune activation, which induces an uncontrolled inflammatory response with sustained hyperactivation of T lymphocytes and macrophages. Only very rare cases of peripheral nerve involvement have been described in HLH. This is the first case showing that peripheral nerves, as other viscera, may be destroyed by the macrophagic infiltration, which characterizes HLH.

Neurocirugía (English Edition), 2020

Background/objectives: Peripheral nerve tumours (PNT) are rare lesions that are generally categor... more Background/objectives: Peripheral nerve tumours (PNT) are rare lesions that are generally categorised as soft tissue tumours, so they are usually managed by a range of surgical disciplines such as plastic, orthopaedic and trauma surgery, dermatology, general surgery and neurosurgery. Appropriate knowledge of the therapeutic indication and surgical management are essential in order to avoid neurological deficit. Materials and methods: This is a retrospective study of 66 tumour lesions in 64 patients, acquired from the joint experience of two surgical teams specialised in peripheral nerve surgery. Results: The most common location was the lower limb and upper limb with 48 tumour lesions. The most common pathological diagnosis was Schwannoma, accounting for 51.5 %. Complete tumour resection was achieved in 81.8 % of the lesions and always with neurophysiological stimulation and/or monitoring. The most common postsurgical complication was neuropathic pain and/or a transient sensory disorder in 15 % of surgeries, with only one persistent motor deficit appearing in two cases that required nerve graft reconstruction.

The quantitative analysis of VEGF using ELISA in various subtypes of grade I meningiomas reported... more The quantitative analysis of VEGF using ELISA in various subtypes of grade I meningiomas reported higher VEGF contents in meningothelial (2.38 ± 0.62 pg/µg protein, n = 7), transitional (1.08 ± 0.21 pg/µg protein, n = 13), and microcystic meningiomas (1.98 ± 0.87 pg/µg protein, n = 5) as compared with fibrous ones (0.36 ± 0.09 pg/µg protein, n = 5). In contrast to VEGF, no difference in the concentrations of bFGF was detected. VEGF levels did not correlate with meningioma grade (1.47 ± 0.23 pg/µg versus 2.29 ± 0.58 pg/µg for 32 and 16 grade I and II, resp), vascularisation (1.53 ± 0.41 pg/µgversus1.96 ± 0.28 pg/µgfor24low and 24 high vascularisated tumours, resp), and brain invasion (2.32±0.59 pg/µgversus1.46±0.27 pg/µg for 7 and 41 patients with and without invasion, resp). The ELISA procedure is, thus, an interesting tool to ensure VEGF and bFGF levels in meningiomas and to test putative correlations with clinical parameters. It is, thus, tempting to speculate that ELISA would als...

Neurocirugía, 2019

Resumen Antecedentes/objetivos Los tumores de los nervios perifericos son lesiones poco frecuente... more Resumen Antecedentes/objetivos Los tumores de los nervios perifericos son lesiones poco frecuentes que se categorizan en general dentro de los tumores de partes blandas, por lo que suelen ser manejados por diferentes disciplinas quirurgicas, como cirugia plastica, cirugia ortopedica y traumatologica, dermatologia, cirugia general y neurocirugia. Un conocimiento apropiado en cuanto a la indicacion terapeutica y el manejo quirurgico es fundamental de cara a evitar un deficit neurologico en el paciente. Materiales y metodos Estudio restrospectivo donde se presenta la experiencia conjunta de 2 equipos quirurgicos especializados en la cirugia de los nervios perifericos, 66 lesiones tumorales, en un total de 64 pacientes. Resultados La localizacion mas frecuente fue el miembro inferior y el miembro superior con 48 lesiones tumorales. El diagnostico anatomopatologico mas frecuente fue el de schwannoma, con un 51,5%. La reseccion tumoral completa se logro en el 81,8% de las lesiones y siempre con estimulacion o monitorizacion neurofisiologica. La complicacion posquirurgica mas frecuente fue el dolor neuropatico o un trastorno sensitivo transitorio en el 15% de las cirugias, apareciendo solo un deficit motor persistente en 2 casos que requirieron reconstruccion con injerto nervioso. Conclusiones Si bien el manejo terapeutico de los tumores benignos como los schwannomas puede considerarse relativamente sencillo aplicando los conceptos basicos en microcirugia de los nervios perifericos, los tumores malignos, si bien son muy infrecuentes, requieren de un manejo multidisciplinar. La opcion de la biopsia prequirurgica a dia de hoy sigue siendo un tema controvertido y sin acuerdo entre los diferentes autores; en nuestra opinion, no es necesaria su realizacion de forma percutanea en la mayoria de los casos.

american journal of biomedicine, 2016

Glioblastoma is the most common and malignant primary brain tumor but its occurrence in the cereb... more Glioblastoma is the most common and malignant primary brain tumor but its occurrence in the cerebellum is very rare. Giving its low occurrence the treatment modalities and outcome of this glioblastoma location are still poorly understood. We present the case of an adult woman with a cerebellar glioblastoma treated at the Clinical Hospital of Montevideo, and we perform a non-systematic review of the literature concerning the clinical, radiological and pathological features of this tumor, as well as its treatment modalities, prognostic factors and outcome.

Calcium and Cellular Metabolism, 1997

Acta Scientiarum. Animal Sciences, 2008

Key words: 16S rRNA, DGGE, rumen, microbial diversity.

Clinical Biochemistry, 2010

Background: Gliomas are tumors of the central nervous system derived from glial cells. They show ... more Background: Gliomas are tumors of the central nervous system derived from glial cells. They show cellular heterogeneity and lack specific diagnostic markers. Although a possible role for the eicosanoid cascade has been suggested in glioma tumorigenesis, the relationship between enzymes and receptors implicated in arachidonic acid metabolism, with histological tumor type has not yet been determined.

Journal of Muscle Research and Cell Motility, 1998

10 and 30mm 2,3-butanedione monoxime (BDM) applied extracellularly to voltage-clamped frog skelet... more 10 and 30mm 2,3-butanedione monoxime (BDM) applied extracellularly to voltage-clamped frog skeletal muscle twitch fibres suppressed both Ca2+ release flux and intramembranous charge movement. Both effects could be clearly separated. The early peak of the Ca2+ release flux was suppressed at every test voltage. The steady level attained at the end of a 100ms clamp depolarization was relatively spared for lower depolarizing pulses, but was as suppressed as the peak at voltages above −20mV. The intramembranous charge movement was affected mainly in the Iγ component. The drug had a distinct effect on the kinetics of the intramembranous charge movement current around the threshold for Ca2+ release. The three kinetic components of Iγ were simultaneously affected. For more positive depolarizations where the kinetic effect was not evident, the oxime had no significant effect on the charge moved. Under conditions in which Iγ was absent (i.e. stretched fibres, intracellular solutions containing 6 to 10mm BAPTA), treatment with 10mm BDM had a small, not significant suppressive effect on the maximum charge moved (Qmax), while it affected Ca2+ release significantly. When 10mm BDM was applied in the presence of 0.2mm tetracaine, the local anaesthetic-resistant Ca2+ release flux was not further suppressed by the oxime.

Journal of Muscle Research and Cell Motility, 1998

10 and 30mm 2,3-butanedione monoxime (BDM) applied extracellularly to voltage-clamped frog skelet... more 10 and 30mm 2,3-butanedione monoxime (BDM) applied extracellularly to voltage-clamped frog skeletal muscle twitch fibres suppressed both Ca2+ release flux and intramembranous charge movement. Both effects could be clearly separated. The early peak of the Ca2+ release flux was suppressed at every test voltage. The steady level attained at the end of a 100ms clamp depolarization was relatively spared for lower depolarizing pulses, but was as suppressed as the peak at voltages above −20mV. The intramembranous charge movement was affected mainly in the Iγ component. The drug had a distinct effect on the kinetics of the intramembranous charge movement current around the threshold for Ca2+ release. The three kinetic components of Iγ were simultaneously affected. For more positive depolarizations where the kinetic effect was not evident, the oxime had no significant effect on the charge moved. Under conditions in which Iγ was absent (i.e. stretched fibres, intracellular solutions containing 6 to 10mm BAPTA), treatment with 10mm BDM had a small, not significant suppressive effect on the maximum charge moved (Qmax), while it affected Ca2+ release significantly. When 10mm BDM was applied in the presence of 0.2mm tetracaine, the local anaesthetic-resistant Ca2+ release flux was not further suppressed by the oxime.

Clinical Biochemistry, Jul 1, 2010

Gliomas are tumors of the central nervous system derived from glial cells. They show cellular het... more Gliomas are tumors of the central nervous system derived from glial cells. They show cellular heterogeneity and lack specific diagnostic markers. Although a possible role for the eicosanoid cascade has been suggested in glioma tumorigenesis, the relationship between enzymes and receptors implicated in arachidonic acid metabolism, with histological tumor type has not yet been determined. Quantitative real-time reverse transcription-polymerase chain reaction was performed to measure and compare transcript levels of enzymes and receptors implicated in both lipoxygenase and cyclooxygenase pathways between oligodendrogliomas, astrocytomas, glioblastomas and mixed oligoastrocytomas. Arachidonic acid metabolism-related enzymes and receptor transcripts (i) were underexpressed in classical oligodendrogliomas compared to astrocytomas and/or glioblastomas, (ii) differed between astrocytomas and glioblastomas and (iii) had an intermediate expression in mixed oligoastrocytomas. mRNA levels of enzymes and receptors implicated both in lipoxygenase and cyclooxygenase pathways differed significantly in gliomas according to the histological type.

Journal of Cancer Science & Therapy, 2010

In view of the important oncogenic action of lipoxygenase (LOX) and cycloxygenase (COX) enzymatic... more In view of the important oncogenic action of lipoxygenase (LOX) and cycloxygenase (COX) enzymatic activities we investigated, by using real time PCR, their presence in human meningiomas. Results indicated the presence of 5-LOX, 12-LOX, 15-LOX1, 15-LOX2, COX-1, COX-2, prostaglandin E (PGE) synthase, prostacyclin (PGI) synthase and thromboxane (TX) synthase transcripts in meningiomas but without relation to the tumor grade, the subtype of meningiomas, the presence of inflammatory infiltrated cells, of an associated edema, mitosis, brain invasion, vascularisation or necrosis. Similar results were found for BLT1 and BLT2 transcripts (encoding LTB4 receptors) and for prostanoid receptor transcripts (EP 1-4 for PGE 2 , IP for PGI 2 and TP for TXA 2). In conclusion, genes encoding enzymatic activities implicated in the eicosanoid cascade are expressed in meningiomas. LOX-and COX-derived arachidonic acid metabolites might act on tumor growth not only by acting on cell growth but also by altering the local cytokine and/ or angiogenic networks.

Acta Neuropathologica, Jul 9, 2004

We report the case of an 11-year-old male who developed subacute diffuse polyradiculoneuropathy, ... more We report the case of an 11-year-old male who developed subacute diffuse polyradiculoneuropathy, associated with digestive symptoms and Epstein-Barr virus infection. Parental consanguinity was present. The laboratory findings including bone marrow smear were consistent with hemophagocytic lymphohistiocytosis (HLH). Electrophysiological study of peripheral nerves revealed an intense and diffuse demyelinating process. The histological nerve lesions were severe and purely demyelinating. Most axons were intact. There was a diffuse infiltration of the nerve parenchyma by mononuclear cells. Immuno-electron microscopic study evidenced entry of macrophages into Schwann cell cytoplasm with dissociation of myelin sheaths. This boy died several months after the onset of the neuropathic symptoms. HLH is a rare genetic or acquired disorder in childhood characterized by abnormal immune activation, which induces an uncontrolled inflammatory response with sustained hyperactivation of T lymphocytes and macrophages. Only very rare cases of peripheral nerve involvement have been described in HLH. This is the first case showing that peripheral nerves, as other viscera, may be destroyed by the macrophagic infiltration, which characterizes HLH.

American journal of biomedicine, Jan 3, 2020

Glioblastoma is the most common and malignant primary brain tumor but its occurrence in the cereb... more Glioblastoma is the most common and malignant primary brain tumor but its occurrence in the cerebellum is very rare. Giving its low occurrence the treatment modalities and outcome of this glioblastoma location are still poorly understood. We present the case of an adult woman with a cerebellar glioblastoma treated at the Clinical Hospital of Montevideo, and we perform a non-systematic review of the literature concerning the clinical, radiological and pathological features of this tumor, as well as its treatment modalities, prognostic factors and outcome.

Neuropathology and Applied Neurobiology, Dec 1, 2006

Meningiomas are common primary intracranial tumours. Platelet‐activating factor (PAF) is an infla... more Meningiomas are common primary intracranial tumours. Platelet‐activating factor (PAF) is an inflammatory and angiogenic lipid mediator involved in several types of cancer. The presence of PAF receptor (PAF‐R) transcripts, the levels of PAF, the phospholipase A2 activity (PLA2, the enzymatic activity implicated in PAF formation) and the PAF acetylhydrolase activity (AHA, the PAF degrading enzyme) were investigated in 49 human meningiomas. PAF‐R transcripts, PAF, PLA2 and AHA were detected in meningiomas. However, their levels did not correlate with biological parameters such as the tumour grade, the presence of associated oedema, necrosis, mitotic index as well as intensity of the neovascularization and chronic inflammatory response. In conclusion, PAF is present in meningiomas where it might act on tumour growth by altering the local angiogenic and/or cytokine networks as previously suggested for human breast and colorectal cancer.

Mediators of Inflammation, 2009

Mediators of Inflammation, 2006

The quantitative analysis of VEGF using ELISA in various subtypes of grade I meningiomas reported... more The quantitative analysis of VEGF using ELISA in various subtypes of grade I meningiomas reported higher VEGF contents in meningothelial (2.38 ± 0.62 pg/µg protein, n = 7), transitional (1.08 ± 0.21 pg/µg protein, n = 13), and microcystic meningiomas (1.98 ± 0.87 pg/µg protein, n = 5) as compared with fibrous ones (0.36 ± 0.09 pg/µg protein, n = 5). In contrast to VEGF, no difference in the concentrations of bFGF was detected. VEGF levels did not correlate with meningioma grade (1.47 ± 0.23 pg/µg versus 2.29 ± 0.58 pg/µg for 32 and 16 grade I and II, resp), vascularisation (1.53 ± 0.41 pg/µg versus 1.96 ± 0.28 pg/µg for 24 low and 24 high vascularisated tumours, resp), and brain invasion (2.32±0.59 pg/µg versus 1.46±0.27 pg/µg for 7 and 41 patients with and without invasion, resp). The ELISA procedure is, thus, an interesting tool to ensure VEGF and bFGF levels in meningiomas and to test putative correlations with clinical parameters. It is, thus, tempting to speculate that ELISA would also be valuable for the quantitative analysis of other angiogenic growth factors and cytokines in intracranial tumours.

Neurocirugía, May 1, 2020

Peripheral nerve tumours (PNT) are rare lesions that are generally categorised as soft tissue tum... more Peripheral nerve tumours (PNT) are rare lesions that are generally categorised as soft tissue tumours, so they are usually managed by a range of surgical disciplines such as plastic, orthopaedic and trauma surgery, dermatology, general surgery and neurosurgery. Appropriate knowledge of the therapeutic indication and surgical management are essential in order to avoid neurological deficit. This is a retrospective study of 66 tumour lesions in 64 patients, acquired from the joint experience of 2surgical teams specialised in peripheral nerve surgery. The most common location was the lower limb and upper limb with 48 tumour lesions. The most common pathological diagnosis was Schwannoma, accounting for 51.5%. Complete tumour resection was achieved in 81.8% of the lesions and always with neurophysiological stimulation and/or monitoring. The most common postsurgical complication was neuropathic pain and/or a transient sensory disorder in 15% of surgeries, with only one persistent motor deficit appearing in 2cases that required nerve graft reconstruction. Although the therapeutic management of benign tumours such as Schwannomas can be considered to be relatively simple thanks to the application of the basic concepts of peripheral nerve microsurgery, malignant tumors, despite being very rare, require multidisciplinary management. The option of pre-surgical biopsy remains a controversial issue and no consensus has been reached among the different authors. In our opinion, percutaneous biopsy is not necessary in most cases.

Acta Neuropathologica, 2004

We report the case of an 11-year-old male who developed subacute diffuse polyradiculoneuropathy, ... more We report the case of an 11-year-old male who developed subacute diffuse polyradiculoneuropathy, associated with digestive symptoms and Epstein-Barr virus infection. Parental consanguinity was present. The laboratory findings including bone marrow smear were consistent with hemophagocytic lymphohistiocytosis (HLH). Electrophysiological study of peripheral nerves revealed an intense and diffuse demyelinating process. The histological nerve lesions were severe and purely demyelinating. Most axons were intact. There was a diffuse infiltration of the nerve parenchyma by mononuclear cells. Immuno-electron microscopic study evidenced entry of macrophages into Schwann cell cytoplasm with dissociation of myelin sheaths. This boy died several months after the onset of the neuropathic symptoms. HLH is a rare genetic or acquired disorder in childhood characterized by abnormal immune activation, which induces an uncontrolled inflammatory response with sustained hyperactivation of T lymphocytes and macrophages. Only very rare cases of peripheral nerve involvement have been described in HLH. This is the first case showing that peripheral nerves, as other viscera, may be destroyed by the macrophagic infiltration, which characterizes HLH.

Neurocirugía (English Edition), 2020

Background/objectives: Peripheral nerve tumours (PNT) are rare lesions that are generally categor... more Background/objectives: Peripheral nerve tumours (PNT) are rare lesions that are generally categorised as soft tissue tumours, so they are usually managed by a range of surgical disciplines such as plastic, orthopaedic and trauma surgery, dermatology, general surgery and neurosurgery. Appropriate knowledge of the therapeutic indication and surgical management are essential in order to avoid neurological deficit. Materials and methods: This is a retrospective study of 66 tumour lesions in 64 patients, acquired from the joint experience of two surgical teams specialised in peripheral nerve surgery. Results: The most common location was the lower limb and upper limb with 48 tumour lesions. The most common pathological diagnosis was Schwannoma, accounting for 51.5 %. Complete tumour resection was achieved in 81.8 % of the lesions and always with neurophysiological stimulation and/or monitoring. The most common postsurgical complication was neuropathic pain and/or a transient sensory disorder in 15 % of surgeries, with only one persistent motor deficit appearing in two cases that required nerve graft reconstruction.

The quantitative analysis of VEGF using ELISA in various subtypes of grade I meningiomas reported... more The quantitative analysis of VEGF using ELISA in various subtypes of grade I meningiomas reported higher VEGF contents in meningothelial (2.38 ± 0.62 pg/µg protein, n = 7), transitional (1.08 ± 0.21 pg/µg protein, n = 13), and microcystic meningiomas (1.98 ± 0.87 pg/µg protein, n = 5) as compared with fibrous ones (0.36 ± 0.09 pg/µg protein, n = 5). In contrast to VEGF, no difference in the concentrations of bFGF was detected. VEGF levels did not correlate with meningioma grade (1.47 ± 0.23 pg/µg versus 2.29 ± 0.58 pg/µg for 32 and 16 grade I and II, resp), vascularisation (1.53 ± 0.41 pg/µgversus1.96 ± 0.28 pg/µgfor24low and 24 high vascularisated tumours, resp), and brain invasion (2.32±0.59 pg/µgversus1.46±0.27 pg/µg for 7 and 41 patients with and without invasion, resp). The ELISA procedure is, thus, an interesting tool to ensure VEGF and bFGF levels in meningiomas and to test putative correlations with clinical parameters. It is, thus, tempting to speculate that ELISA would als...

Neurocirugía, 2019

Resumen Antecedentes/objetivos Los tumores de los nervios perifericos son lesiones poco frecuente... more Resumen Antecedentes/objetivos Los tumores de los nervios perifericos son lesiones poco frecuentes que se categorizan en general dentro de los tumores de partes blandas, por lo que suelen ser manejados por diferentes disciplinas quirurgicas, como cirugia plastica, cirugia ortopedica y traumatologica, dermatologia, cirugia general y neurocirugia. Un conocimiento apropiado en cuanto a la indicacion terapeutica y el manejo quirurgico es fundamental de cara a evitar un deficit neurologico en el paciente. Materiales y metodos Estudio restrospectivo donde se presenta la experiencia conjunta de 2 equipos quirurgicos especializados en la cirugia de los nervios perifericos, 66 lesiones tumorales, en un total de 64 pacientes. Resultados La localizacion mas frecuente fue el miembro inferior y el miembro superior con 48 lesiones tumorales. El diagnostico anatomopatologico mas frecuente fue el de schwannoma, con un 51,5%. La reseccion tumoral completa se logro en el 81,8% de las lesiones y siempre con estimulacion o monitorizacion neurofisiologica. La complicacion posquirurgica mas frecuente fue el dolor neuropatico o un trastorno sensitivo transitorio en el 15% de las cirugias, apareciendo solo un deficit motor persistente en 2 casos que requirieron reconstruccion con injerto nervioso. Conclusiones Si bien el manejo terapeutico de los tumores benignos como los schwannomas puede considerarse relativamente sencillo aplicando los conceptos basicos en microcirugia de los nervios perifericos, los tumores malignos, si bien son muy infrecuentes, requieren de un manejo multidisciplinar. La opcion de la biopsia prequirurgica a dia de hoy sigue siendo un tema controvertido y sin acuerdo entre los diferentes autores; en nuestra opinion, no es necesaria su realizacion de forma percutanea en la mayoria de los casos.

american journal of biomedicine, 2016

Glioblastoma is the most common and malignant primary brain tumor but its occurrence in the cereb... more Glioblastoma is the most common and malignant primary brain tumor but its occurrence in the cerebellum is very rare. Giving its low occurrence the treatment modalities and outcome of this glioblastoma location are still poorly understood. We present the case of an adult woman with a cerebellar glioblastoma treated at the Clinical Hospital of Montevideo, and we perform a non-systematic review of the literature concerning the clinical, radiological and pathological features of this tumor, as well as its treatment modalities, prognostic factors and outcome.

Calcium and Cellular Metabolism, 1997

Acta Scientiarum. Animal Sciences, 2008

Key words: 16S rRNA, DGGE, rumen, microbial diversity.

Clinical Biochemistry, 2010

Background: Gliomas are tumors of the central nervous system derived from glial cells. They show ... more Background: Gliomas are tumors of the central nervous system derived from glial cells. They show cellular heterogeneity and lack specific diagnostic markers. Although a possible role for the eicosanoid cascade has been suggested in glioma tumorigenesis, the relationship between enzymes and receptors implicated in arachidonic acid metabolism, with histological tumor type has not yet been determined.

Journal of Muscle Research and Cell Motility, 1998

10 and 30mm 2,3-butanedione monoxime (BDM) applied extracellularly to voltage-clamped frog skelet... more 10 and 30mm 2,3-butanedione monoxime (BDM) applied extracellularly to voltage-clamped frog skeletal muscle twitch fibres suppressed both Ca2+ release flux and intramembranous charge movement. Both effects could be clearly separated. The early peak of the Ca2+ release flux was suppressed at every test voltage. The steady level attained at the end of a 100ms clamp depolarization was relatively spared for lower depolarizing pulses, but was as suppressed as the peak at voltages above −20mV. The intramembranous charge movement was affected mainly in the Iγ component. The drug had a distinct effect on the kinetics of the intramembranous charge movement current around the threshold for Ca2+ release. The three kinetic components of Iγ were simultaneously affected. For more positive depolarizations where the kinetic effect was not evident, the oxime had no significant effect on the charge moved. Under conditions in which Iγ was absent (i.e. stretched fibres, intracellular solutions containing 6 to 10mm BAPTA), treatment with 10mm BDM had a small, not significant suppressive effect on the maximum charge moved (Qmax), while it affected Ca2+ release significantly. When 10mm BDM was applied in the presence of 0.2mm tetracaine, the local anaesthetic-resistant Ca2+ release flux was not further suppressed by the oxime.

Journal of Muscle Research and Cell Motility, 1998

10 and 30mm 2,3-butanedione monoxime (BDM) applied extracellularly to voltage-clamped frog skelet... more 10 and 30mm 2,3-butanedione monoxime (BDM) applied extracellularly to voltage-clamped frog skeletal muscle twitch fibres suppressed both Ca2+ release flux and intramembranous charge movement. Both effects could be clearly separated. The early peak of the Ca2+ release flux was suppressed at every test voltage. The steady level attained at the end of a 100ms clamp depolarization was relatively spared for lower depolarizing pulses, but was as suppressed as the peak at voltages above −20mV. The intramembranous charge movement was affected mainly in the Iγ component. The drug had a distinct effect on the kinetics of the intramembranous charge movement current around the threshold for Ca2+ release. The three kinetic components of Iγ were simultaneously affected. For more positive depolarizations where the kinetic effect was not evident, the oxime had no significant effect on the charge moved. Under conditions in which Iγ was absent (i.e. stretched fibres, intracellular solutions containing 6 to 10mm BAPTA), treatment with 10mm BDM had a small, not significant suppressive effect on the maximum charge moved (Qmax), while it affected Ca2+ release significantly. When 10mm BDM was applied in the presence of 0.2mm tetracaine, the local anaesthetic-resistant Ca2+ release flux was not further suppressed by the oxime.