Gustavo Michel - Academia.edu (original) (raw)

Papers by Gustavo Michel

American journal of physiology. Regulatory, integrative and comparative physiology, 2006

The locus coeruleus (LC) has been suggested as a CO2 chemoreceptor site in mammals. This nucleus ... more The locus coeruleus (LC) has been suggested as a CO2 chemoreceptor site in mammals. This nucleus is a mesencephalic structure of the amphibian brain and is probably homologous to the LC in mammals. There are no data available for the role of LC in the central chemoreception of amphibians. Thus the present study was designed to investigate whether LC of toads (Bufo schneideri) is a CO2/H+ chemoreceptor site. Fos immunoreactivity was used to verify whether the nucleus is activated by hypercarbia (5% CO2 in air). In addition, we assessed the role of noradrenergic LC neurons on respiratory and cardiovascular responses to hypercarbia by using 6-hydroxydopamine lesion. To further explore the role of LC in central chemosensitivity, we examined the effects of microinjection of solutions with different pH values (7.2, 7.4, 7.6, 7.8, and 8.0) into the nucleus. Our main findings were that 1) a marked increase in c-fos-positive cells in the LC was induced after 3 h of breathing a hypercarbic ga...

AJP: Regulatory, Integrative and Comparative Physiology, 2006

The locus coeruleus (LC) has been suggested as a CO2 chemoreceptor site in mammals. This nucleus ... more The locus coeruleus (LC) has been suggested as a CO2 chemoreceptor site in mammals. This nucleus is a mesencephalic structure of the amphibian brain and is probably homologous to the LC in mammals. There are no data available for the role of LC in the central chemoreception of amphibians. Thus the present study was designed to investigate whether LC of toads (Bufo schneideri) is a CO2/H+ chemoreceptor site. Fos immunoreactivity was used to verify whether the nucleus is activated by hypercarbia (5% CO2 in air). In addition, we assessed the role of noradrenergic LC neurons on respiratory and cardiovascular responses to hypercarbia by using 6-hydroxydopamine lesion. To further explore the role of LC in central chemosensitivity, we examined the effects of microinjection of solutions with different pH values (7.2, 7.4, 7.6, 7.8, and 8.0) into the nucleus. Our main findings were that 1) a marked increase in c-fos-positive cells in the LC was induced after 3 h of breathing a hypercarbic gas mixture; 2) chemical lesions in the LC attenuated the increase of the ventilatory response to hypercarbia but did not affect ventilation under resting conditions; and 3) microinjection with acid solutions (pH = 7.2, 7.4, and 7.6) into the LC elicited an increased ventilation, indicating that the LC of toads participates in the central chemoreception.

Mycopathologia, Mar 1, 2011

Paracoccidioidomycosis (PCM) is a systemic mycosis caused by Paracoccidioides brasiliensis, which... more Paracoccidioidomycosis (PCM) is a systemic mycosis caused by Paracoccidioides brasiliensis, which is endemic in many regions of Latin America. We describe the case of a 60-year-old man from a region endemic for PCM who presented with a long history of left hip pain. He had been treated over the past 3 years with immunosuppressive drugs (methotrexate, leflunomide, and adalimumab) for rheumatoid arthritis (RA). A hip radiograph showed lytic bone lesions, and a chest radiograph showed an expansive excavated lesion in the left lung, suggestive of a lung cancer with bone metastases. A left hip joint biopsy was inconclusive, but histological analysis of a surgical lung biopsy specimen was consistent with P. brasiliensis infection. Treatment with intravenous amphotericin B (50 mg/day) and hydrocortisone (25 mg/day) was initiated. However, increasing hip pain resulted in the amputation of the left lower limb, and the analysis of the surgical specimen revealed a diagnosis of bone sarcoma. Postoperatively, the patient developed sepsis and died approximately 1 month later. To our knowledge, this is the first report of PCM in a patient with RA who had been treated with immunosuppressive drugs, in particular TNF-α blocking agents. The atypical presentation (left hip pain alone) emphasizes the importance of considering PCM in the differential diagnosis of patients with pulmonary lesions and osteolytic lesions who live in a region endemic for PCM. This case report also demonstrates that health professionals in these regions must pay close attention to patients receiving immunosuppressive drugs because of the possibility of reactivating quiescent P. brasiliensis lesions.

Mycopathologia, 1998

A case of paracoccidioidomycosis presenting as a solitary pulmonary nodular lesion in a patient w... more A case of paracoccidioidomycosis presenting as a solitary pulmonary nodular lesion in a patient with acquired immunodeficiency syndrome (AIDS) is presented. This case illustrates that restricted lung lesions can also be found and diagnosed in immunodeficient patients.

Jornal De Pneumologia, 2003

Jornal Brasileiro de Pneumologia

Microscopic Polyangiitis is a form of Anti-Neutrophil Cytoplasmic Antibody (ANCA)-associated smal... more Microscopic Polyangiitis is a form of Anti-Neutrophil Cytoplasmic Antibody (ANCA)-associated small-vessel vasculitis that preferentially involves venules, capillaries and arterioles and may also involve arteries and veins. It is one of the most common primary systemic ...

Mycopathologia, 1998

A case of paracoccidioidomycosis presenting as a solitary pulmonary nodular lesion in a patient w... more A case of paracoccidioidomycosis presenting as a solitary pulmonary nodular lesion in a patient with acquired immunodeficiency syndrome (AIDS) is presented. This case illustrates that restricted lung lesions can also be found and diagnosed in immunodeficient patients.

Mycopathologia, 1997

A case of solitary pulmonary paracoccidioidal lesion-paracoccidioidoma-is related. It is the firs... more A case of solitary pulmonary paracoccidioidal lesion-paracoccidioidoma-is related. It is the first reported case in Brazil. The literature on spontaneously regressive lesion of paracoccidioidomycosis is commented upon.

Jornal brasileiro de pneumologia : publicaça̋o oficial da Sociedade Brasileira de Pneumologia e Tisilogia, 2009

Community-acquired pneumonia continues to be the acute infectious disease that has the greatest m... more Community-acquired pneumonia continues to be the acute infectious disease that has the greatest medical and social impact regarding morbidity and treatment costs. Children and the elderly are more susceptible to severe complications, thereby justifying the fact that the prevention measures adopted have focused on these age brackets. Despite the advances in the knowledge of etiology and physiopathology, as well as the improvement in preliminary clinical and therapeutic methods, various questions merit further investigation. This is due to the clinical, social, demographical and structural diversity, which cannot be fully predicted. Consequently, guidelines are published in order to compile the most recent knowledge in a systematic way and to promote the rational use of that knowledge in medical practice. Therefore, guidelines are not a rigid set of rules that must be followed, but first and foremost a tool to be used in a critical way, bearing in mind the variability of biological an...

Jornal Brasileiro de Pneumologia, 2012

Objective: Staphylococcal pneumonia typically presents high rates of morbidity and mortality. It ... more Objective: Staphylococcal pneumonia typically presents high rates of morbidity and mortality. It typically occurs in cases of influenza (airborne transmission) or during episodes of bacteremia (blood-borne transmission). Methods: A retrospective and descriptive study was conducted in patients admitted to our hospital between January of 1992 and December of 2003. All of he patients included had been diagnosed with community-acquired pneumonia

Jornal de Pneumologia, 2003

... Enderece para correspondencia-José Wellington Alves dos Santos, Rúa Venancio Aires, 2.020/403... more ... Enderece para correspondencia-José Wellington Alves dos Santos, Rúa Venancio Aires, 2.020/403-97010-004-Santa Maria, RS, Brasil. ... 2. Ortiz-Saracho J, Vidal R, Delgado E, Fogue L, Perez-Rodriguez E. Bronchocentric granulomatosis in a nonasthmatic patient without etio ...

Jornal Brasileiro de Pneumologia, 2004

Poliangeíte microscópica é uma forma de vasculite sistêmica de pequenos vasos, associada aos anti... more Poliangeíte microscópica é uma forma de vasculite sistêmica de pequenos vasos, associada aos anticorpos anticitoplasma de neutrófilos, que preferencialmente acomete vênulas, capilares e arteríolas, e que pode, entretanto, envolver artérias e veias. Está entre as vasculites ...

Jornal Brasileiro de Pneumologia, 2009

Paciente feminina, 69 anos, natural e proce-dente de São Sepé (RS), dona-de-casa, tabagista (30 a... more Paciente feminina, 69 anos, natural e proce-dente de São Sepé (RS), dona-de-casa, tabagista (30 anos-maço), submetida à tireoidectomia há 20 anos e portadora de artrite reumatoide há 14 anos. Não havia história epidemiológica clara quanto à possível exposição fúngica. ...

Jornal brasileiro de pneumologia : publicaça̋o oficial da Sociedade Brasileira de Pneumologia e Tisilogia, 2008

Staphylococcal pneumonia typically presents high rates of morbidity and mortality. It typically o... more Staphylococcal pneumonia typically presents high rates of morbidity and mortality. It typically occurs in cases of influenza (airborne transmission) or during episodes of bacteremia (blood-borne transmission). A retrospective and descriptive study was conducted in patients admitted to our hospital between January of 1992 and December of 2003. All of he patients included had been diagnosed with community-acquired pneumonia caused by Staphylococcus aureus. All were older than 14 years of age, and none were intravenous drug users. Community-acquired pneumonia was identified in 332 cases, of which 24 (7.3%) were identified as cases of staphylococcal pneumonia. Age ranged from 14 to 89 years. Fifteen patients were male, and nine were female. Twelve patients met the criteria for severe pneumonia. Chest X-rays showed unilateral consolidation in 14 cases, bilateral consolidation in 10, pleural effusion in 15, rapid radiological progression of pulmonary lesions in 14, cavitation in 6 and pne...

Jornal brasileiro de pneumologia : publicaça̋o oficial da Sociedade Brasileira de Pneumologia e Tisilogia, 2009

Histoplasmosis is a systemic mycosis caused by the thermally dimorphic fungus Histoplasma capsula... more Histoplasmosis is a systemic mycosis caused by the thermally dimorphic fungus Histoplasma capsulatum, which can be isolated from soil contaminated with droppings from birds or bats. Chronic cavitary pulmonary histoplasmosis is one of the rarest clinical presentations of this disease. The differential diagnosis with tuberculosis should be made in patients presenting with cavitated lesions in upper lung segments. We report the case of a female patient with chronic cavitary pulmonary histoplasmosis who had presented with progressive dyspnea and worsening of the radiological pattern over a four-year period.

Journal of Bronchology, 2005

ABSTRACT

Respiratory Medicine, 2004

Mycopathologia, 2011

Paracoccidioidomycosis (PCM) is a systemic mycosis caused by Paracoccidioides brasiliensis, which... more Paracoccidioidomycosis (PCM) is a systemic mycosis caused by Paracoccidioides brasiliensis, which is endemic in many regions of Latin America. We describe the case of a 60-year-old man from a region endemic for PCM who presented with a long history of left hip pain. He had been treated over the past 3 years with immunosuppressive drugs (methotrexate, leflunomide, and adalimumab) for rheumatoid arthritis (RA). A hip radiograph showed lytic bone lesions, and a chest radiograph showed an expansive excavated lesion in the left lung, suggestive of a lung cancer with bone metastases. A left hip joint biopsy was inconclusive, but histological analysis of a surgical lung biopsy specimen was consistent with P. brasiliensis infection. Treatment with intravenous amphotericin B (50 mg/day) and hydrocortisone (25 mg/day) was initiated. However, increasing hip pain resulted in the amputation of the left lower limb, and the analysis of the surgical specimen revealed a diagnosis of bone sarcoma. Postoperatively, the patient developed sepsis and died approximately 1 month later. To our knowledge, this is the first report of PCM in a patient with RA who had been treated with immunosuppressive drugs, in particular TNF-α blocking agents. The atypical presentation (left hip pain alone) emphasizes the importance of considering PCM in the differential diagnosis of patients with pulmonary lesions and osteolytic lesions who live in a region endemic for PCM. This case report also demonstrates that health professionals in these regions must pay close attention to patients receiving immunosuppressive drugs because of the possibility of reactivating quiescent P. brasiliensis lesions.

Mycopathologia, 2000

Asymptomatic presentations of chronic pulmonary paracoccidiodomycosis have been reported since 19... more Asymptomatic presentations of chronic pulmonary paracoccidiodomycosis have been reported since 1959, usually published in case series of paracoccidiodomycosis. Incidental radiographic findings on chest roentgenogram led to diagnostic evaluation in these cases. An unusual case in a female patient is described, and 24 previously reported cases are reviewed.

American journal of physiology. Regulatory, integrative and comparative physiology, 2006

The locus coeruleus (LC) has been suggested as a CO2 chemoreceptor site in mammals. This nucleus ... more The locus coeruleus (LC) has been suggested as a CO2 chemoreceptor site in mammals. This nucleus is a mesencephalic structure of the amphibian brain and is probably homologous to the LC in mammals. There are no data available for the role of LC in the central chemoreception of amphibians. Thus the present study was designed to investigate whether LC of toads (Bufo schneideri) is a CO2/H+ chemoreceptor site. Fos immunoreactivity was used to verify whether the nucleus is activated by hypercarbia (5% CO2 in air). In addition, we assessed the role of noradrenergic LC neurons on respiratory and cardiovascular responses to hypercarbia by using 6-hydroxydopamine lesion. To further explore the role of LC in central chemosensitivity, we examined the effects of microinjection of solutions with different pH values (7.2, 7.4, 7.6, 7.8, and 8.0) into the nucleus. Our main findings were that 1) a marked increase in c-fos-positive cells in the LC was induced after 3 h of breathing a hypercarbic ga...

AJP: Regulatory, Integrative and Comparative Physiology, 2006

The locus coeruleus (LC) has been suggested as a CO2 chemoreceptor site in mammals. This nucleus ... more The locus coeruleus (LC) has been suggested as a CO2 chemoreceptor site in mammals. This nucleus is a mesencephalic structure of the amphibian brain and is probably homologous to the LC in mammals. There are no data available for the role of LC in the central chemoreception of amphibians. Thus the present study was designed to investigate whether LC of toads (Bufo schneideri) is a CO2/H+ chemoreceptor site. Fos immunoreactivity was used to verify whether the nucleus is activated by hypercarbia (5% CO2 in air). In addition, we assessed the role of noradrenergic LC neurons on respiratory and cardiovascular responses to hypercarbia by using 6-hydroxydopamine lesion. To further explore the role of LC in central chemosensitivity, we examined the effects of microinjection of solutions with different pH values (7.2, 7.4, 7.6, 7.8, and 8.0) into the nucleus. Our main findings were that 1) a marked increase in c-fos-positive cells in the LC was induced after 3 h of breathing a hypercarbic gas mixture; 2) chemical lesions in the LC attenuated the increase of the ventilatory response to hypercarbia but did not affect ventilation under resting conditions; and 3) microinjection with acid solutions (pH = 7.2, 7.4, and 7.6) into the LC elicited an increased ventilation, indicating that the LC of toads participates in the central chemoreception.

Mycopathologia, Mar 1, 2011

Paracoccidioidomycosis (PCM) is a systemic mycosis caused by Paracoccidioides brasiliensis, which... more Paracoccidioidomycosis (PCM) is a systemic mycosis caused by Paracoccidioides brasiliensis, which is endemic in many regions of Latin America. We describe the case of a 60-year-old man from a region endemic for PCM who presented with a long history of left hip pain. He had been treated over the past 3 years with immunosuppressive drugs (methotrexate, leflunomide, and adalimumab) for rheumatoid arthritis (RA). A hip radiograph showed lytic bone lesions, and a chest radiograph showed an expansive excavated lesion in the left lung, suggestive of a lung cancer with bone metastases. A left hip joint biopsy was inconclusive, but histological analysis of a surgical lung biopsy specimen was consistent with P. brasiliensis infection. Treatment with intravenous amphotericin B (50 mg/day) and hydrocortisone (25 mg/day) was initiated. However, increasing hip pain resulted in the amputation of the left lower limb, and the analysis of the surgical specimen revealed a diagnosis of bone sarcoma. Postoperatively, the patient developed sepsis and died approximately 1 month later. To our knowledge, this is the first report of PCM in a patient with RA who had been treated with immunosuppressive drugs, in particular TNF-α blocking agents. The atypical presentation (left hip pain alone) emphasizes the importance of considering PCM in the differential diagnosis of patients with pulmonary lesions and osteolytic lesions who live in a region endemic for PCM. This case report also demonstrates that health professionals in these regions must pay close attention to patients receiving immunosuppressive drugs because of the possibility of reactivating quiescent P. brasiliensis lesions.

Mycopathologia, 1998

A case of paracoccidioidomycosis presenting as a solitary pulmonary nodular lesion in a patient w... more A case of paracoccidioidomycosis presenting as a solitary pulmonary nodular lesion in a patient with acquired immunodeficiency syndrome (AIDS) is presented. This case illustrates that restricted lung lesions can also be found and diagnosed in immunodeficient patients.

Jornal De Pneumologia, 2003

Jornal Brasileiro de Pneumologia

Microscopic Polyangiitis is a form of Anti-Neutrophil Cytoplasmic Antibody (ANCA)-associated smal... more Microscopic Polyangiitis is a form of Anti-Neutrophil Cytoplasmic Antibody (ANCA)-associated small-vessel vasculitis that preferentially involves venules, capillaries and arterioles and may also involve arteries and veins. It is one of the most common primary systemic ...

Mycopathologia, 1998

A case of paracoccidioidomycosis presenting as a solitary pulmonary nodular lesion in a patient w... more A case of paracoccidioidomycosis presenting as a solitary pulmonary nodular lesion in a patient with acquired immunodeficiency syndrome (AIDS) is presented. This case illustrates that restricted lung lesions can also be found and diagnosed in immunodeficient patients.

Mycopathologia, 1997

A case of solitary pulmonary paracoccidioidal lesion-paracoccidioidoma-is related. It is the firs... more A case of solitary pulmonary paracoccidioidal lesion-paracoccidioidoma-is related. It is the first reported case in Brazil. The literature on spontaneously regressive lesion of paracoccidioidomycosis is commented upon.

Jornal brasileiro de pneumologia : publicaça̋o oficial da Sociedade Brasileira de Pneumologia e Tisilogia, 2009

Community-acquired pneumonia continues to be the acute infectious disease that has the greatest m... more Community-acquired pneumonia continues to be the acute infectious disease that has the greatest medical and social impact regarding morbidity and treatment costs. Children and the elderly are more susceptible to severe complications, thereby justifying the fact that the prevention measures adopted have focused on these age brackets. Despite the advances in the knowledge of etiology and physiopathology, as well as the improvement in preliminary clinical and therapeutic methods, various questions merit further investigation. This is due to the clinical, social, demographical and structural diversity, which cannot be fully predicted. Consequently, guidelines are published in order to compile the most recent knowledge in a systematic way and to promote the rational use of that knowledge in medical practice. Therefore, guidelines are not a rigid set of rules that must be followed, but first and foremost a tool to be used in a critical way, bearing in mind the variability of biological an...

Jornal Brasileiro de Pneumologia, 2012

Objective: Staphylococcal pneumonia typically presents high rates of morbidity and mortality. It ... more Objective: Staphylococcal pneumonia typically presents high rates of morbidity and mortality. It typically occurs in cases of influenza (airborne transmission) or during episodes of bacteremia (blood-borne transmission). Methods: A retrospective and descriptive study was conducted in patients admitted to our hospital between January of 1992 and December of 2003. All of he patients included had been diagnosed with community-acquired pneumonia

Jornal de Pneumologia, 2003

... Enderece para correspondencia-José Wellington Alves dos Santos, Rúa Venancio Aires, 2.020/403... more ... Enderece para correspondencia-José Wellington Alves dos Santos, Rúa Venancio Aires, 2.020/403-97010-004-Santa Maria, RS, Brasil. ... 2. Ortiz-Saracho J, Vidal R, Delgado E, Fogue L, Perez-Rodriguez E. Bronchocentric granulomatosis in a nonasthmatic patient without etio ...

Jornal Brasileiro de Pneumologia, 2004

Poliangeíte microscópica é uma forma de vasculite sistêmica de pequenos vasos, associada aos anti... more Poliangeíte microscópica é uma forma de vasculite sistêmica de pequenos vasos, associada aos anticorpos anticitoplasma de neutrófilos, que preferencialmente acomete vênulas, capilares e arteríolas, e que pode, entretanto, envolver artérias e veias. Está entre as vasculites ...

Jornal Brasileiro de Pneumologia, 2009

Paciente feminina, 69 anos, natural e proce-dente de São Sepé (RS), dona-de-casa, tabagista (30 a... more Paciente feminina, 69 anos, natural e proce-dente de São Sepé (RS), dona-de-casa, tabagista (30 anos-maço), submetida à tireoidectomia há 20 anos e portadora de artrite reumatoide há 14 anos. Não havia história epidemiológica clara quanto à possível exposição fúngica. ...

Jornal brasileiro de pneumologia : publicaça̋o oficial da Sociedade Brasileira de Pneumologia e Tisilogia, 2008

Staphylococcal pneumonia typically presents high rates of morbidity and mortality. It typically o... more Staphylococcal pneumonia typically presents high rates of morbidity and mortality. It typically occurs in cases of influenza (airborne transmission) or during episodes of bacteremia (blood-borne transmission). A retrospective and descriptive study was conducted in patients admitted to our hospital between January of 1992 and December of 2003. All of he patients included had been diagnosed with community-acquired pneumonia caused by Staphylococcus aureus. All were older than 14 years of age, and none were intravenous drug users. Community-acquired pneumonia was identified in 332 cases, of which 24 (7.3%) were identified as cases of staphylococcal pneumonia. Age ranged from 14 to 89 years. Fifteen patients were male, and nine were female. Twelve patients met the criteria for severe pneumonia. Chest X-rays showed unilateral consolidation in 14 cases, bilateral consolidation in 10, pleural effusion in 15, rapid radiological progression of pulmonary lesions in 14, cavitation in 6 and pne...

Jornal brasileiro de pneumologia : publicaça̋o oficial da Sociedade Brasileira de Pneumologia e Tisilogia, 2009

Histoplasmosis is a systemic mycosis caused by the thermally dimorphic fungus Histoplasma capsula... more Histoplasmosis is a systemic mycosis caused by the thermally dimorphic fungus Histoplasma capsulatum, which can be isolated from soil contaminated with droppings from birds or bats. Chronic cavitary pulmonary histoplasmosis is one of the rarest clinical presentations of this disease. The differential diagnosis with tuberculosis should be made in patients presenting with cavitated lesions in upper lung segments. We report the case of a female patient with chronic cavitary pulmonary histoplasmosis who had presented with progressive dyspnea and worsening of the radiological pattern over a four-year period.

Journal of Bronchology, 2005

ABSTRACT

Respiratory Medicine, 2004

Mycopathologia, 2011

Paracoccidioidomycosis (PCM) is a systemic mycosis caused by Paracoccidioides brasiliensis, which... more Paracoccidioidomycosis (PCM) is a systemic mycosis caused by Paracoccidioides brasiliensis, which is endemic in many regions of Latin America. We describe the case of a 60-year-old man from a region endemic for PCM who presented with a long history of left hip pain. He had been treated over the past 3 years with immunosuppressive drugs (methotrexate, leflunomide, and adalimumab) for rheumatoid arthritis (RA). A hip radiograph showed lytic bone lesions, and a chest radiograph showed an expansive excavated lesion in the left lung, suggestive of a lung cancer with bone metastases. A left hip joint biopsy was inconclusive, but histological analysis of a surgical lung biopsy specimen was consistent with P. brasiliensis infection. Treatment with intravenous amphotericin B (50 mg/day) and hydrocortisone (25 mg/day) was initiated. However, increasing hip pain resulted in the amputation of the left lower limb, and the analysis of the surgical specimen revealed a diagnosis of bone sarcoma. Postoperatively, the patient developed sepsis and died approximately 1 month later. To our knowledge, this is the first report of PCM in a patient with RA who had been treated with immunosuppressive drugs, in particular TNF-α blocking agents. The atypical presentation (left hip pain alone) emphasizes the importance of considering PCM in the differential diagnosis of patients with pulmonary lesions and osteolytic lesions who live in a region endemic for PCM. This case report also demonstrates that health professionals in these regions must pay close attention to patients receiving immunosuppressive drugs because of the possibility of reactivating quiescent P. brasiliensis lesions.

Mycopathologia, 2000

Asymptomatic presentations of chronic pulmonary paracoccidiodomycosis have been reported since 19... more Asymptomatic presentations of chronic pulmonary paracoccidiodomycosis have been reported since 1959, usually published in case series of paracoccidiodomycosis. Incidental radiographic findings on chest roentgenogram led to diagnostic evaluation in these cases. An unusual case in a female patient is described, and 24 previously reported cases are reviewed.