Charles Feldman - Academia.edu (original) (raw)

Uploads

Papers by Charles Feldman

Journal of thoracic disease, 2017

determine the appropriate site of care, the extent of the microbiological work-up and the choice ... more determine the appropriate site of care, the extent of the microbiological work-up and the choice of initial empiric antibiotic treatment.  The CURB-65 score (CRB-65 for outpatients) is the recommended disease severity score for patients with CAP (A II).  Severity scoring systems should not be the sole basis for making decisions regarding site of care. Disease severity score should always be interpreted in conjunction with a thorough clinical assessment of the patient (A II). Site of care decisions Site of care decisions, such as outpatient vs. inpatient care or general ward vs. intensive care unit, are important areas for improvement of CAP care. Decisions should be based on the clinical condition of the patients, on the disease severity scoring, on the social circumstances of the patients and on available resources.  Patients with a CRB-65 score of 0 or a CURB-65 score of 0 or 1 are at low risk of death and may be considered for treatment at home (A II).  Patients with a CRB-65 score of 1 or 2 or a CURB-65 score of 2 are at increased risk of death, and should be referred to hospital (A II).  Patients with a CRB-65 score or CURB-65 score of 3 or more are at high risk of death and require urgent hospital admission and even consideration for possible admission to a high-care or intensive care unit (A II). Additional tests Blood-based biomarkers Blood-based biomarkers may be used to aid the diagnosis of CAP and to assist in severity assessment.  Routine measurement of CRP or PCT when the diagnosis is not in doubt is discouraged but may be used to measure response to therapy in the critically ill (A III).  Measurement of CRP, particularly in primary care settings and when CXR is unavailable, may aid the diagnosis of CAP (A II).  Measurement of CRP or PCT in emergency departments may be considered in patients with acute respiratory illness when the diagnosis of CAP is in doubt (B II).  Urea should be measured in all hospitalised patients with CAP to assist in severity scoring (A I). Microbiological tests  Blood cultures (BCs) should be taken prior to antibiotic therapy in all patients with CAP with a CURB-65 score of ≥2 (A II).  BCs should be considered in patients with lower CURB-65 scores, but who require hospitalisation for other reasons (B II).  BCs should not be performed on patients with CAP who are being treated as outpatients (A II).  A sputum sample or tracheal aspirate (collected at intubation) should be submitted for Gram stain and culture for all patients with CAP with a CURB-65 score of ≥2 (A II).  Sputum samples can be considered in patients with CURB-65 scores of <2 who require hospitalisation for reasons such as comorbidities (B II).  Sputum samples should not be submitted on patients with CAP who are being treated as outpatients (A II).  The use of the pneumococcal UAT is not routinely recommended for patients with CAP (B II).  The Legionella UAT should be considered, where available, for patients with severe CAP (B III).  The use of rapid antigen tests for influenza is not recommended (B II).  In patients with severe CAP during the influenza season (typically June to September) nasopharyngeal samples may be considered for detection of influenza (B II).  The routine use of molecular tests to detect additional pathogens is not recommended (B II).  Serology for 'atypical' pathogens should not be routinely performed (A II). Investigating for tuberculosis TB is a cause of CAP and clinical features are not reliable in distinguishing TB from other aetiologies. However, TB should be suspected in patients presenting with CAP who are co-infected with HIV, have a subacute history and in those who initially do not respond to antibiotics. Specific investigations for TB should be performed as indicated.  In the following high risk patient groups presenting with CAP there should be a low threshold for investigation for pulmonary TB: HIV-infected, diabetics, admission to ICU, subacute illness or those not responding to empiric antimicrobial therapy (A II).  A GeneXpert MTB/RIF TM (Cepheid, Sunnyvale, USA) assay performed on a single expectorated or induced sputum specimen is the preferred first line 1472 Boyles et al. South Africa CAP guideline

Journal of Infection, 2017

Highlights  Pneumolysin (Ply) activates production of PAF and thromboxane A 2 (TxA 2) by neutrop... more Highlights  Pneumolysin (Ply) activates production of PAF and thromboxane A 2 (TxA 2) by neutrophils.  Ply also promotes formation of pro-thrombotic neutrophil:platelet (NP) aggregates.  Ply-mediated aggregate formation is independent of PAF and TxA 2.  P-selectin (CD62P) and protease-activated receptor 1 are involved in Ply-induced NP aggregation.  Ply-mediated NP aggregate formation may contribute to pulmonary and myocardial injury.

Journal of Applied Physics, Aug 1, 1976

Investigations of switching parameters in amorphous boron thin films containing carbon have been ... more Investigations of switching parameters in amorphous boron thin films containing carbon have been conducted under rapid single-pulse voltage conditions. Measurements were compared with switching parameters determined from low-voltage long-duration signals. Single high-voltage pulses altered virgin samples more than similar samples previously examined under low-voltage (curve-tracer) signals. Delay times and switching times were considerably shorter under the high-voltage pulse condition. Film thickness had, as found previously, little effect on threshold voltage under curve-tracer or long-duration pulses, but had a large effect under rapid high-pulse conditions. At very high voltages and short pulse duration, the switching threshold became field dependent and the switching process became primarily electronic. The results are discussed in terms of an electrothermal model in which the switching process becomes less dominated by thermal effects as the duration of the applied voltage is decreased.

Le Journal De Physique Colloques, 1974

Southern African Journal of Infectious Diseases, Jun 5, 2010

Disseminated Klebsiella bacteraemic syndrome and cryptogenic invasive Klebsiella pneumoniae-assoc... more Disseminated Klebsiella bacteraemic syndrome and cryptogenic invasive Klebsiella pneumoniae-associated liver abscess (CIKPLA) have been well described in Taiwan. However, CIKPLA has never been described in patients in South Africa. The main aim of this case report is to describe the occurrence of this syndrome in a South African man, not of Asian descent, in order to highlight to clinicians the possibility of its occurrence in South Africa.

Circulation, Nov 25, 2014

Current Opinion in Lipidology, 2011

Low endothelial shear stress (ESS) plays an important role in the progression and severity of ath... more Low endothelial shear stress (ESS) plays an important role in the progression and severity of atherosclerotic lesions. As 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) appear to stabilize plaque, it would be valuable to understand how statins affect the nature of lesions in the proatherogenic and proinflammatory environment of low ESS and the effect of statins on that atherosclerotic process. The purpose of this review is to summarize the relationship among low ESS, high-risk plaque and statins. Low ESS is a critically important determinant of plaque development and progression to high-risk plaques with large necrotic lipid core, intensive inflammation and thin fibrous cap. In addition to the proatherogenic phenotypic switching in areas of low ESS, local LDL cholesterol concentrations are also increased in areas of low ESS, which exacerbates the local atherogenic process. In experimental models, statins appear to reduce the inflammation in lesions associated with low ESS and reduce the atherosclerotic phenotype even in these high-risk prone vascular areas. The relationship between low ESS and statins has not been fully investigated, but the available data underscore the vasculoprotective effect of statins. Understanding the mechanisms whereby statins reduce the atherogenic and inflammatory phenotype resulting from a low ESS environment would provide new insights to design strategies to prevent regional formation of high-risk, inflamed plaques likely to rupture and cause an adverse clinical event.

Circulation, Nov 20, 2012

ABSTRACT Fluids and Electrolytes: A Conceptual Approach. By E. Kinsey M. Smith, 1991, New York: C... more ABSTRACT Fluids and Electrolytes: A Conceptual Approach. By E. Kinsey M. Smith, 1991, New York: Churchill Livingstone, 19.75.MakingPresentations(Video)andMakingPresentations(Guidebook).EditedbyJaneWestbergandHilliardJason,1991,Boulder,CO:CenterforInstructionalSupport,19.75.Making Presentations (Video) and Making Presentations (Guidebook). Edited by Jane Westberg and Hilliard Jason, 1991, Boulder, CO: Center for Instructional Support, 19.75.MakingPresentations(Video)andMakingPresentations(Guidebook).EditedbyJaneWestbergandHilliardJason,1991,Boulder,CO:CenterforInstructionalSupport,150 (video), $15 (guidebook). Bulk rates are available for the guidebook.

Southern African Journal of Infectious Diseases, Aug 28, 2013

Circulation, Nov 23, 2010

J Amer Coll Cardiol, 2003

Southern African Journal of Infectious Diseases, Dec 11, 2012

Journal of Electrocardiology, 2003

To investigate the possibility of simplifying electrocardiogram (ECG) recording in children, we c... more To investigate the possibility of simplifying electrocardiogram (ECG) recording in children, we compared waveforms in conventional 12-lead ECGs to those derived from EASI leads in 221 children of various ages. The conventional 12-lead ECGs and the ECGs using EASI electrode positions were collected simultaneously. We developed and determined the value of agespecific transformation coefficients for use in deriving 12-lead ECGs from the signals recorded at the EASI sites. We compared the results of using agespecific coefficients to the results of using adult coefficients and studied the "goodness-of-fit" between the conventional and the derived 12-lead ECGs. The age-specific coefficients performed slightly better than the adult coefficients, and good agreement was usually attained between the conventional 12-lead ECG and the EASI-derived 12-lead ECG. Our conclusion is that EASI leads in children have the same high levels of "goodness-of-fit" to replicate conventional 12-lead ECG waveforms, as reported earlier in adults.

Journal of Electrocardiology, 2003

To investigate the possibility of simplifying electrocardiogram (ECG) recording in children, we c... more To investigate the possibility of simplifying electrocardiogram (ECG) recording in children, we compared waveforms in conventional 12-lead ECGs to those derived from EASI leads in 221 children of various ages. The conventional 12-lead ECGs and the ECGs using EASI electrode positions were collected simultaneously. We developed and determined the value of agespecific transformation coefficients for use in deriving 12-lead ECGs from the signals recorded at the EASI sites. We compared the results of using agespecific coefficients to the results of using adult coefficients and studied the "goodness-of-fit" between the conventional and the derived 12-lead ECGs. The age-specific coefficients performed slightly better than the adult coefficients, and good agreement was usually attained between the conventional 12-lead ECG and the EASI-derived 12-lead ECG. Our conclusion is that EASI leads in children have the same high levels of "goodness-of-fit" to replicate conventional 12-lead ECG waveforms, as reported earlier in adults.

Journal of thoracic disease, 2017

determine the appropriate site of care, the extent of the microbiological work-up and the choice ... more determine the appropriate site of care, the extent of the microbiological work-up and the choice of initial empiric antibiotic treatment.  The CURB-65 score (CRB-65 for outpatients) is the recommended disease severity score for patients with CAP (A II).  Severity scoring systems should not be the sole basis for making decisions regarding site of care. Disease severity score should always be interpreted in conjunction with a thorough clinical assessment of the patient (A II). Site of care decisions Site of care decisions, such as outpatient vs. inpatient care or general ward vs. intensive care unit, are important areas for improvement of CAP care. Decisions should be based on the clinical condition of the patients, on the disease severity scoring, on the social circumstances of the patients and on available resources.  Patients with a CRB-65 score of 0 or a CURB-65 score of 0 or 1 are at low risk of death and may be considered for treatment at home (A II).  Patients with a CRB-65 score of 1 or 2 or a CURB-65 score of 2 are at increased risk of death, and should be referred to hospital (A II).  Patients with a CRB-65 score or CURB-65 score of 3 or more are at high risk of death and require urgent hospital admission and even consideration for possible admission to a high-care or intensive care unit (A II). Additional tests Blood-based biomarkers Blood-based biomarkers may be used to aid the diagnosis of CAP and to assist in severity assessment.  Routine measurement of CRP or PCT when the diagnosis is not in doubt is discouraged but may be used to measure response to therapy in the critically ill (A III).  Measurement of CRP, particularly in primary care settings and when CXR is unavailable, may aid the diagnosis of CAP (A II).  Measurement of CRP or PCT in emergency departments may be considered in patients with acute respiratory illness when the diagnosis of CAP is in doubt (B II).  Urea should be measured in all hospitalised patients with CAP to assist in severity scoring (A I). Microbiological tests  Blood cultures (BCs) should be taken prior to antibiotic therapy in all patients with CAP with a CURB-65 score of ≥2 (A II).  BCs should be considered in patients with lower CURB-65 scores, but who require hospitalisation for other reasons (B II).  BCs should not be performed on patients with CAP who are being treated as outpatients (A II).  A sputum sample or tracheal aspirate (collected at intubation) should be submitted for Gram stain and culture for all patients with CAP with a CURB-65 score of ≥2 (A II).  Sputum samples can be considered in patients with CURB-65 scores of <2 who require hospitalisation for reasons such as comorbidities (B II).  Sputum samples should not be submitted on patients with CAP who are being treated as outpatients (A II).  The use of the pneumococcal UAT is not routinely recommended for patients with CAP (B II).  The Legionella UAT should be considered, where available, for patients with severe CAP (B III).  The use of rapid antigen tests for influenza is not recommended (B II).  In patients with severe CAP during the influenza season (typically June to September) nasopharyngeal samples may be considered for detection of influenza (B II).  The routine use of molecular tests to detect additional pathogens is not recommended (B II).  Serology for 'atypical' pathogens should not be routinely performed (A II). Investigating for tuberculosis TB is a cause of CAP and clinical features are not reliable in distinguishing TB from other aetiologies. However, TB should be suspected in patients presenting with CAP who are co-infected with HIV, have a subacute history and in those who initially do not respond to antibiotics. Specific investigations for TB should be performed as indicated.  In the following high risk patient groups presenting with CAP there should be a low threshold for investigation for pulmonary TB: HIV-infected, diabetics, admission to ICU, subacute illness or those not responding to empiric antimicrobial therapy (A II).  A GeneXpert MTB/RIF TM (Cepheid, Sunnyvale, USA) assay performed on a single expectorated or induced sputum specimen is the preferred first line 1472 Boyles et al. South Africa CAP guideline

Journal of Infection, 2017

Highlights  Pneumolysin (Ply) activates production of PAF and thromboxane A 2 (TxA 2) by neutrop... more Highlights  Pneumolysin (Ply) activates production of PAF and thromboxane A 2 (TxA 2) by neutrophils.  Ply also promotes formation of pro-thrombotic neutrophil:platelet (NP) aggregates.  Ply-mediated aggregate formation is independent of PAF and TxA 2.  P-selectin (CD62P) and protease-activated receptor 1 are involved in Ply-induced NP aggregation.  Ply-mediated NP aggregate formation may contribute to pulmonary and myocardial injury.

Journal of Applied Physics, Aug 1, 1976

Investigations of switching parameters in amorphous boron thin films containing carbon have been ... more Investigations of switching parameters in amorphous boron thin films containing carbon have been conducted under rapid single-pulse voltage conditions. Measurements were compared with switching parameters determined from low-voltage long-duration signals. Single high-voltage pulses altered virgin samples more than similar samples previously examined under low-voltage (curve-tracer) signals. Delay times and switching times were considerably shorter under the high-voltage pulse condition. Film thickness had, as found previously, little effect on threshold voltage under curve-tracer or long-duration pulses, but had a large effect under rapid high-pulse conditions. At very high voltages and short pulse duration, the switching threshold became field dependent and the switching process became primarily electronic. The results are discussed in terms of an electrothermal model in which the switching process becomes less dominated by thermal effects as the duration of the applied voltage is decreased.

Le Journal De Physique Colloques, 1974

Southern African Journal of Infectious Diseases, Jun 5, 2010

Disseminated Klebsiella bacteraemic syndrome and cryptogenic invasive Klebsiella pneumoniae-assoc... more Disseminated Klebsiella bacteraemic syndrome and cryptogenic invasive Klebsiella pneumoniae-associated liver abscess (CIKPLA) have been well described in Taiwan. However, CIKPLA has never been described in patients in South Africa. The main aim of this case report is to describe the occurrence of this syndrome in a South African man, not of Asian descent, in order to highlight to clinicians the possibility of its occurrence in South Africa.

Circulation, Nov 25, 2014

Current Opinion in Lipidology, 2011

Low endothelial shear stress (ESS) plays an important role in the progression and severity of ath... more Low endothelial shear stress (ESS) plays an important role in the progression and severity of atherosclerotic lesions. As 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) appear to stabilize plaque, it would be valuable to understand how statins affect the nature of lesions in the proatherogenic and proinflammatory environment of low ESS and the effect of statins on that atherosclerotic process. The purpose of this review is to summarize the relationship among low ESS, high-risk plaque and statins. Low ESS is a critically important determinant of plaque development and progression to high-risk plaques with large necrotic lipid core, intensive inflammation and thin fibrous cap. In addition to the proatherogenic phenotypic switching in areas of low ESS, local LDL cholesterol concentrations are also increased in areas of low ESS, which exacerbates the local atherogenic process. In experimental models, statins appear to reduce the inflammation in lesions associated with low ESS and reduce the atherosclerotic phenotype even in these high-risk prone vascular areas. The relationship between low ESS and statins has not been fully investigated, but the available data underscore the vasculoprotective effect of statins. Understanding the mechanisms whereby statins reduce the atherogenic and inflammatory phenotype resulting from a low ESS environment would provide new insights to design strategies to prevent regional formation of high-risk, inflamed plaques likely to rupture and cause an adverse clinical event.

Circulation, Nov 20, 2012

ABSTRACT Fluids and Electrolytes: A Conceptual Approach. By E. Kinsey M. Smith, 1991, New York: C... more ABSTRACT Fluids and Electrolytes: A Conceptual Approach. By E. Kinsey M. Smith, 1991, New York: Churchill Livingstone, 19.75.MakingPresentations(Video)andMakingPresentations(Guidebook).EditedbyJaneWestbergandHilliardJason,1991,Boulder,CO:CenterforInstructionalSupport,19.75.Making Presentations (Video) and Making Presentations (Guidebook). Edited by Jane Westberg and Hilliard Jason, 1991, Boulder, CO: Center for Instructional Support, 19.75.MakingPresentations(Video)andMakingPresentations(Guidebook).EditedbyJaneWestbergandHilliardJason,1991,Boulder,CO:CenterforInstructionalSupport,150 (video), $15 (guidebook). Bulk rates are available for the guidebook.

Southern African Journal of Infectious Diseases, Aug 28, 2013

Circulation, Nov 23, 2010

J Amer Coll Cardiol, 2003

Southern African Journal of Infectious Diseases, Dec 11, 2012

Journal of Electrocardiology, 2003

To investigate the possibility of simplifying electrocardiogram (ECG) recording in children, we c... more To investigate the possibility of simplifying electrocardiogram (ECG) recording in children, we compared waveforms in conventional 12-lead ECGs to those derived from EASI leads in 221 children of various ages. The conventional 12-lead ECGs and the ECGs using EASI electrode positions were collected simultaneously. We developed and determined the value of agespecific transformation coefficients for use in deriving 12-lead ECGs from the signals recorded at the EASI sites. We compared the results of using agespecific coefficients to the results of using adult coefficients and studied the "goodness-of-fit" between the conventional and the derived 12-lead ECGs. The age-specific coefficients performed slightly better than the adult coefficients, and good agreement was usually attained between the conventional 12-lead ECG and the EASI-derived 12-lead ECG. Our conclusion is that EASI leads in children have the same high levels of "goodness-of-fit" to replicate conventional 12-lead ECG waveforms, as reported earlier in adults.

Journal of Electrocardiology, 2003

To investigate the possibility of simplifying electrocardiogram (ECG) recording in children, we c... more To investigate the possibility of simplifying electrocardiogram (ECG) recording in children, we compared waveforms in conventional 12-lead ECGs to those derived from EASI leads in 221 children of various ages. The conventional 12-lead ECGs and the ECGs using EASI electrode positions were collected simultaneously. We developed and determined the value of agespecific transformation coefficients for use in deriving 12-lead ECGs from the signals recorded at the EASI sites. We compared the results of using agespecific coefficients to the results of using adult coefficients and studied the "goodness-of-fit" between the conventional and the derived 12-lead ECGs. The age-specific coefficients performed slightly better than the adult coefficients, and good agreement was usually attained between the conventional 12-lead ECG and the EASI-derived 12-lead ECG. Our conclusion is that EASI leads in children have the same high levels of "goodness-of-fit" to replicate conventional 12-lead ECG waveforms, as reported earlier in adults.