Avry Chagnac - Academia.edu (original) (raw)

Papers by Avry Chagnac

Research paper thumbnail of Orthostatic hypotension in the elderly: are the diagnostic criteria adequate?

Journal of Human Hypertension, 2004

Orthostatic hypotension (OH) is a common finding in the elderly. OH is defined as a fall of at le... more Orthostatic hypotension (OH) is a common finding in the elderly. OH is defined as a fall of at least 20 mmHg in systolic blood pressure (BP) and/or 10 mmHg in diastolic BP upon assuming an upright posture. Some patients exhibit a fall in BP of less than the defined OH upon standing. The aim of this study was to estimate the prevalence of BP changes not defined as OH among elderly in-patients and to assess the relationship between these changes in the morning and the occurrence of OH during the day. Postural BP measurements were performed in 502 in-patients; in the morning, early afternoon, and in the evening. We defined intermediate postural drop (ID) in BP as a decrease of 10-19 mmHg in systolic BP and/or of 5-9 mmHg in diastolic BP. We observed that OH and ID occurred in 39.2 and 18.5% of the measurements in the morning, respectively. The prevalence of OH and ID was lower in the evening than in the morning (Po0.05) and afternoon (Po0.005). Postural BP changes in the morning correlated with those occurring later in the day. Patients who had ID in the morning had a 57% probability of having OH later during the day. In conclusions, ID is prevalent in elderly in-patients. ID in the morning predicts OH later in the day. Thus, postural BP drops below the OH range may be an important finding in the geriatric population.

Research paper thumbnail of An open-label study of lamivudine for chronic hepatitis B in six patients with chronic renal failure before and after kidney transplantation

The American journal of gastroenterology, 2000

The course of hepatitis B virus (HBV) infection after kidney transplantation is aggressive, with ... more The course of hepatitis B virus (HBV) infection after kidney transplantation is aggressive, with a high mortality rate from liver disease mainly in patients who were serum hepatitis B e antigen (HBeAg) or HBV DNA-positive before transplantation. Lamivudine has been shown to be a potent inhibitor of HBV replication. The aim of the study was to examine the efficacy and safety of lamivudine therapy in patients with chronic renal failure and chronic HBV infection. The study population consisted of six potential candidates for kidney or combined kidney and liver transplantation aged 25-49 yr (four patients had already undergone a kidney transplantation and developed chronic rejection). All were serum HBeAg and/or HBV DNA-positive and had been maintained on hemodialysis for 3 months to 3 yr. The duration of HBV infection was 7 months to 14 yr. Serum alanine aminotransferase (ALT) levels ranged from 72 to 610 U/L (median, 158 U/L). Liver histological evaluation showed mild to moderate chro...

Research paper thumbnail of The effects of weight loss on renal function in patients with severe obesity

Journal of the …, 2003

Severe obesity is associated with increased renal plasma flow (RPF) and glomerular filtration rat... more Severe obesity is associated with increased renal plasma flow (RPF) and glomerular filtration rate (GFR). The aim of the present study was to examine whether weight loss may reverse glomerular dysfunction in obese subjects without overt renal disease. Renal glomerular function was studied in eight subjects with severe obesity (body mass index [BMI] 48.0 Ϯ 2.4) before and after weight loss. Nine healthy subjects served as controls. GFR and RPF were determined by measuring inulin and PAH clearance. In the obese group, GFR (145 Ϯ 14 ml/min) and RPF (803 Ϯ 39 ml/min) exceeded the control value by 61% (90 Ϯ 5 ml/min, P ϭ 0.001) and 32% (610 Ϯ 41 ml/min, P Ͻ 0.005), respectively. Consequently, filtration fraction was increased.

Research paper thumbnail of Acute Phosphate Nephropathy—An Emerging Threat

The American Journal of the Medical Sciences, 2008

Acute phosphate nephropathy (APN) is a clinicopathological entity causing renal failure, after in... more Acute phosphate nephropathy (APN) is a clinicopathological entity causing renal failure, after ingestion of oral sodium phosphate solution (OSPS). Approximately 25 cases have been described, but OSPS is still widely used. This study reports a further 5 cases and discusses the ever-growing significance of APN. Five cases of APN were included, 3 retrospectively whereas 2 were diagnosed prospectively. In all, use of OSPS was established, and other causes of nephrocalcinosis were excluded. Average age was 67.4 +/- 7.0 years, with a female preponderance (4:1). All patients had hypertension. Baseline serum creatinine: 0.7 to 1.2 mg/dL (creatinine clearance: 52 to 77 mL/min). Time from colonoscopy to presentation was 56 +/- 36 days. Serum creatinine levels at presentation: 1.4 to 3.6 mg/dL. Time from colonoscopy to renal biopsy was 123 +/- 88 days. Urinalysis showed minimal proteinuria, leucocyturia, and hematuria. One patient had renal glucosuria. All patients were anemic (hemoglobin 8.8-11.4 gr/dL). Serum calcium and phosphate were normal. One required hemodialysis. Mean follow-up was 36 +/- 17 months. Serum creatinine levels at end of follow-up were 1.3 to 3.1 mg/dL. Renal function did not recover completely in any patient. Four required long-term erythropoietin treatment. The prominent histopathological findings were calcium-phosphate tubular depositions (100%), interstitial fibrosis (80%), hypertensive changes (80%), and acute tubular degenerative and regenerative changes (60%). APN is a serious, irreversible renal complication of OSPS. It is probably under-recognized. Risk factors include female gender, older age, hypertension, and renal failure, although it may occur with preexisting normal renal function.

Research paper thumbnail of Effect of obesity-induced hyperfiltration on renal peritubular capillary oncotic pressure

Studies in animals and humans have shown that salt retention may be involved in the pathogenesis ... more Studies in animals and humans have shown that salt retention may be involved in the pathogenesis of obesity-induced hypertension. One of the factors which may theoretically promote renal salt reabsorption is an elevated peritubular capillary oncotic pressure. Obesity is associated with elevated filtration fraction (FF) and high glomerular filtration rate (GFR). An increased FF is predicted to elevate the renal peritubular capillary oncotic pressure (⌸ PT), thus promoting salt reabsorption. We have previously reported the effects of weight loss on GFR and RPF in subjects with severe obesity (Chagnac et al, J Am Soc Nephrol, 2003). The aim of the present study is to estimate the effect of weight loss on the ⌸ PT of obese subjects. Eight subjects with severe obesity (BMI 38 to 61) underwent renal function tests before and after weight loss. GFR and renal plasma flow (RPF) were measured as inulin and amino-hippurate clearance respectively. FF was calculated as GFR/RPF. The afferent arteriolar oncotic pressure (⌸ A) was estimated from the plasma protein concentration. ⌸ PT was calculated as ⌸ PT ϭ ⌸ A /(1-FF). Following weight loss, BMI decreased from 48Ϯ2.4 to 32.1Ϯ1.5 (Pϭ0.001). Systolic blood pressure decreased from 143Ϯ6 to 133Ϯ6 mm Hg (PϽ0.005). GFR decreased from 145Ϯ14 to 110Ϯ7 ml/min (Pϭ0.01). RPF decreased from 732Ϯ35 to 628Ϯ37 ml/min (PϽ0.02). FF was 0.18Ϯ 0.01 before and 0.16Ϯ0.01 after weight loss (Pϭ0.07). ⌸ A was 25.8Ϯ1.1 mm Hg before and 24.5Ϯ1.0 mm Hg after weight loss (P NS). ⌸ PT decreased from 31.5Ϯ1.4 to 29.2 Ϯ 1.3 mm Hg following weight loss (PϽ 0.05). This study shows that ⌸ PT decreases following weight loss. This finding suggests that obesity-induced hyperfiltration results in an increased ⌸ PT. The increased ⌸ PT may play a role in the pathogenesis of obesity-associated hypertension.

Research paper thumbnail of Angiotensin-converting enzyme inhibition and ventricular remodeling after myocardial infarction

Annual review of physiology

Despite the trend for a decrease in fatality rates due to coronary heart disease, hospitalization... more Despite the trend for a decrease in fatality rates due to coronary heart disease, hospitalizations for acute myocardial infarction and its long-term sequelae have remained high. In the United States, approximately 675,000 ...

Research paper thumbnail of Orthostatic hypotension in the elderly: are the diagnostic criteria adequate?

Journal of Human Hypertension, 2004

Orthostatic hypotension (OH) is a common finding in the elderly. OH is defined as a fall of at le... more Orthostatic hypotension (OH) is a common finding in the elderly. OH is defined as a fall of at least 20 mmHg in systolic blood pressure (BP) and/or 10 mmHg in diastolic BP upon assuming an upright posture. Some patients exhibit a fall in BP of less than the defined OH upon standing. The aim of this study was to estimate the prevalence of BP changes not defined as OH among elderly in-patients and to assess the relationship between these changes in the morning and the occurrence of OH during the day. Postural BP measurements were performed in 502 in-patients; in the morning, early afternoon, and in the evening. We defined intermediate postural drop (ID) in BP as a decrease of 10-19 mmHg in systolic BP and/or of 5-9 mmHg in diastolic BP. We observed that OH and ID occurred in 39.2 and 18.5% of the measurements in the morning, respectively. The prevalence of OH and ID was lower in the evening than in the morning (Po0.05) and afternoon (Po0.005). Postural BP changes in the morning correlated with those occurring later in the day. Patients who had ID in the morning had a 57% probability of having OH later during the day. In conclusions, ID is prevalent in elderly in-patients. ID in the morning predicts OH later in the day. Thus, postural BP drops below the OH range may be an important finding in the geriatric population.

Research paper thumbnail of An open-label study of lamivudine for chronic hepatitis B in six patients with chronic renal failure before and after kidney transplantation

The American journal of gastroenterology, 2000

The course of hepatitis B virus (HBV) infection after kidney transplantation is aggressive, with ... more The course of hepatitis B virus (HBV) infection after kidney transplantation is aggressive, with a high mortality rate from liver disease mainly in patients who were serum hepatitis B e antigen (HBeAg) or HBV DNA-positive before transplantation. Lamivudine has been shown to be a potent inhibitor of HBV replication. The aim of the study was to examine the efficacy and safety of lamivudine therapy in patients with chronic renal failure and chronic HBV infection. The study population consisted of six potential candidates for kidney or combined kidney and liver transplantation aged 25-49 yr (four patients had already undergone a kidney transplantation and developed chronic rejection). All were serum HBeAg and/or HBV DNA-positive and had been maintained on hemodialysis for 3 months to 3 yr. The duration of HBV infection was 7 months to 14 yr. Serum alanine aminotransferase (ALT) levels ranged from 72 to 610 U/L (median, 158 U/L). Liver histological evaluation showed mild to moderate chro...

Research paper thumbnail of The effects of weight loss on renal function in patients with severe obesity

Journal of the …, 2003

Severe obesity is associated with increased renal plasma flow (RPF) and glomerular filtration rat... more Severe obesity is associated with increased renal plasma flow (RPF) and glomerular filtration rate (GFR). The aim of the present study was to examine whether weight loss may reverse glomerular dysfunction in obese subjects without overt renal disease. Renal glomerular function was studied in eight subjects with severe obesity (body mass index [BMI] 48.0 Ϯ 2.4) before and after weight loss. Nine healthy subjects served as controls. GFR and RPF were determined by measuring inulin and PAH clearance. In the obese group, GFR (145 Ϯ 14 ml/min) and RPF (803 Ϯ 39 ml/min) exceeded the control value by 61% (90 Ϯ 5 ml/min, P ϭ 0.001) and 32% (610 Ϯ 41 ml/min, P Ͻ 0.005), respectively. Consequently, filtration fraction was increased.

Research paper thumbnail of Acute Phosphate Nephropathy—An Emerging Threat

The American Journal of the Medical Sciences, 2008

Acute phosphate nephropathy (APN) is a clinicopathological entity causing renal failure, after in... more Acute phosphate nephropathy (APN) is a clinicopathological entity causing renal failure, after ingestion of oral sodium phosphate solution (OSPS). Approximately 25 cases have been described, but OSPS is still widely used. This study reports a further 5 cases and discusses the ever-growing significance of APN. Five cases of APN were included, 3 retrospectively whereas 2 were diagnosed prospectively. In all, use of OSPS was established, and other causes of nephrocalcinosis were excluded. Average age was 67.4 +/- 7.0 years, with a female preponderance (4:1). All patients had hypertension. Baseline serum creatinine: 0.7 to 1.2 mg/dL (creatinine clearance: 52 to 77 mL/min). Time from colonoscopy to presentation was 56 +/- 36 days. Serum creatinine levels at presentation: 1.4 to 3.6 mg/dL. Time from colonoscopy to renal biopsy was 123 +/- 88 days. Urinalysis showed minimal proteinuria, leucocyturia, and hematuria. One patient had renal glucosuria. All patients were anemic (hemoglobin 8.8-11.4 gr/dL). Serum calcium and phosphate were normal. One required hemodialysis. Mean follow-up was 36 +/- 17 months. Serum creatinine levels at end of follow-up were 1.3 to 3.1 mg/dL. Renal function did not recover completely in any patient. Four required long-term erythropoietin treatment. The prominent histopathological findings were calcium-phosphate tubular depositions (100%), interstitial fibrosis (80%), hypertensive changes (80%), and acute tubular degenerative and regenerative changes (60%). APN is a serious, irreversible renal complication of OSPS. It is probably under-recognized. Risk factors include female gender, older age, hypertension, and renal failure, although it may occur with preexisting normal renal function.

Research paper thumbnail of Effect of obesity-induced hyperfiltration on renal peritubular capillary oncotic pressure

Studies in animals and humans have shown that salt retention may be involved in the pathogenesis ... more Studies in animals and humans have shown that salt retention may be involved in the pathogenesis of obesity-induced hypertension. One of the factors which may theoretically promote renal salt reabsorption is an elevated peritubular capillary oncotic pressure. Obesity is associated with elevated filtration fraction (FF) and high glomerular filtration rate (GFR). An increased FF is predicted to elevate the renal peritubular capillary oncotic pressure (⌸ PT), thus promoting salt reabsorption. We have previously reported the effects of weight loss on GFR and RPF in subjects with severe obesity (Chagnac et al, J Am Soc Nephrol, 2003). The aim of the present study is to estimate the effect of weight loss on the ⌸ PT of obese subjects. Eight subjects with severe obesity (BMI 38 to 61) underwent renal function tests before and after weight loss. GFR and renal plasma flow (RPF) were measured as inulin and amino-hippurate clearance respectively. FF was calculated as GFR/RPF. The afferent arteriolar oncotic pressure (⌸ A) was estimated from the plasma protein concentration. ⌸ PT was calculated as ⌸ PT ϭ ⌸ A /(1-FF). Following weight loss, BMI decreased from 48Ϯ2.4 to 32.1Ϯ1.5 (Pϭ0.001). Systolic blood pressure decreased from 143Ϯ6 to 133Ϯ6 mm Hg (PϽ0.005). GFR decreased from 145Ϯ14 to 110Ϯ7 ml/min (Pϭ0.01). RPF decreased from 732Ϯ35 to 628Ϯ37 ml/min (PϽ0.02). FF was 0.18Ϯ 0.01 before and 0.16Ϯ0.01 after weight loss (Pϭ0.07). ⌸ A was 25.8Ϯ1.1 mm Hg before and 24.5Ϯ1.0 mm Hg after weight loss (P NS). ⌸ PT decreased from 31.5Ϯ1.4 to 29.2 Ϯ 1.3 mm Hg following weight loss (PϽ 0.05). This study shows that ⌸ PT decreases following weight loss. This finding suggests that obesity-induced hyperfiltration results in an increased ⌸ PT. The increased ⌸ PT may play a role in the pathogenesis of obesity-associated hypertension.

Research paper thumbnail of Angiotensin-converting enzyme inhibition and ventricular remodeling after myocardial infarction

Annual review of physiology

Despite the trend for a decrease in fatality rates due to coronary heart disease, hospitalization... more Despite the trend for a decrease in fatality rates due to coronary heart disease, hospitalizations for acute myocardial infarction and its long-term sequelae have remained high. In the United States, approximately 675,000 ...