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Papers by M. Chondronikola

Research paper thumbnail of A percutaneous needle biopsy technique for sampling the supraclavicular brown adipose tissue depot of humans

International journal of obesity (2005), Jan 29, 2015

Brown adipose tissue (BAT) has been proposed as a potential target tissue against obesity and its... more Brown adipose tissue (BAT) has been proposed as a potential target tissue against obesity and its related metabolic complications. Although the molecular and functional characteristics of BAT have been intensively studied in rodents, only a few studies have used human BAT specimens due to the difficulty of sampling human BAT deposits. We established a novel positron emission tomography and computed tomography-guided Bergström needle biopsy technique to acquire human BAT specimens from the supraclavicular area in human subjects. Forty-three biopsies were performed on 23 participants. The procedure was tolerated well by the majority of participants. No major complications were noted. Numbness (9.6%) and hematoma (2.3%) were the two minor complications noted, which fully resolved. Thus, the proposed biopsy technique can be considered safe with only minimal risk of adverse events. Adoption of the proposed method is expected to increase the sampling of the supraclavicular BAT depot for r...

Research paper thumbnail of Uncoupled skeletal muscle mitochondria contribute to hypermetabolism in severely burned adults

American journal of physiology. Endocrinology and metabolism, 2014

Elevated metabolic rate is a hallmark of the stress response to severe burn injury. This response... more Elevated metabolic rate is a hallmark of the stress response to severe burn injury. This response is mediated in part by adrenergic stress and is responsive to changes in ambient temperature. We hypothesize that uncoupling of oxidative phosphorylation in skeletal muscle mitochondria contributes to increased metabolic rate in burn survivors. Here, we determined skeletal muscle mitochondrial function in healthy and severely burned adults. Indirect calorimetry was used to estimate metabolic rate in burn patients. Quadriceps muscle biopsies were collected on two separate occasions (11 ± 5 and 21 ± 8 days postinjury) from six severely burned adults (68 ± 19% of total body surface area burned) and 12 healthy adults. Leak, coupled, and uncoupled mitochondrial respiration was determined in permeabilized myofiber bundles. Metabolic rate was significantly greater than predicted values for burn patients at both time points (P < 0.05). Skeletal muscle oxidative capacity, citrate synthase act...

Research paper thumbnail of Acute amino acid intake does not alter mitochondrial function in older adults

Research paper thumbnail of The effect of acute oral amino acid intake on fatty acid oxidation

Research paper thumbnail of Severe thermal trauma alters adipose tissue mitochondrial function in children

Research paper thumbnail of Brown Adipose Tissue Improves Whole-Body Glucose Homeostasis and Insulin Sensitivity in Humans

Diabetes, 2014

Brown adipose tissue (BAT) has attracted scientific interest as an antidiabetic tissue owing to i... more Brown adipose tissue (BAT) has attracted scientific interest as an antidiabetic tissue owing to its ability to dissipate energy as heat. Despite a plethora of data concerning the role of BAT in glucose metabolism in rodents, the role of BAT (if any) in glucose metabolism in humans remains unclear. To investigate whether BAT activation alters whole-body glucose homeostasis and insulin sensitivity in humans, we studied seven BAT-positive (BAT(+)) men and five BAT-negative (BAT(-)) men under thermoneutral conditions and after prolonged (5-8 h) cold exposure (CE). The two groups were similar in age, BMI, and adiposity. CE significantly increased resting energy expenditure, whole-body glucose disposal, plasma glucose oxidation, and insulin sensitivity in the BAT(+) group only. These results demonstrate a physiologically significant role of BAT in whole-body energy expenditure, glucose homeostasis, and insulin sensitivity in humans, and support the notion that BAT may function as an antidiabetic tissue in humans.

Research paper thumbnail of Dietary Intake in Asthma and Atopy: A Pediatric Case-Control Study

Journal of the American Dietetic Association, 2011

Learning Outcome: Participants will be able to advise clients looking for ergogenic aids to consu... more Learning Outcome: Participants will be able to advise clients looking for ergogenic aids to consume whole beetroot, a healthy nitrate source, to improve running velocity.

Research paper thumbnail of Impact of Obesity on Body Image Dissatisfaction and Social Integration Difficulty in Adolescent and Young Adult Burn Injury Survivors

Journal of Burn Care & Research, 2013

Burn injury deformities and obesity have been associated with social integration difficulty and b... more Burn injury deformities and obesity have been associated with social integration difficulty and body image dissatisfaction. However, the combined effects of obesity and burn injury on social integration difficulty and body image dissatisfaction are unknown. Adolescent and young adult burn injury survivors were categorized as normal weight (n = 47) or overweight and obese (n = 21). Burn-related and anthropometric information were obtained from patients' medical records, and validated questionnaires were used to assess the main outcomes and possible confounders. Analysis of covariance and multiple linear regressions were performed to evaluate the objectives of this study. Obese and overweight burn injury survivors did not experience increased body image dissatisfaction (12 ± 4.3 vs 13.1 ± 4.4; P = .57) or social integration difficulty (17.5 ± 6.9 vs 15.5 ± 5.7; P = .16) compared with normal weight burn injury survivors. Weight status was not a significant predictor of social integration difficulty or body image dissatisfaction (P = .19 and P = .24, respectively). However, mobility limitations predicted greater social integration difficulty (P = .005) and body image dissatisfaction (P < .001), whereas higher weight status at burn was a borderline significant predictor of body image dissatisfaction (P = .05). Obese and overweight adolescents and young adults, who sustained major burn injury as children, do not experience greater social integration difficulty and body image dissatisfaction compared with normal weight burn injury survivors. Mobility limitations and higher weight status at burn are likely more important factors affecting the long-term social integration difficulty and body image dissatisfaction of these young people. (J Burn Care Res 2013;34:102-108)

Research paper thumbnail of An Obesity-Preventive Lifestyle Score Is Negatively Associated with Physician-Diagnosed Asthma: Results from a Pediatric Case-Control Study

Journal of the Academy of Nutrition and Dietetics, 2013

Research paper thumbnail of A percutaneous needle biopsy technique for sampling the supraclavicular brown adipose tissue depot of humans

International journal of obesity (2005), Jan 29, 2015

Brown adipose tissue (BAT) has been proposed as a potential target tissue against obesity and its... more Brown adipose tissue (BAT) has been proposed as a potential target tissue against obesity and its related metabolic complications. Although the molecular and functional characteristics of BAT have been intensively studied in rodents, only a few studies have used human BAT specimens due to the difficulty of sampling human BAT deposits. We established a novel positron emission tomography and computed tomography-guided Bergström needle biopsy technique to acquire human BAT specimens from the supraclavicular area in human subjects. Forty-three biopsies were performed on 23 participants. The procedure was tolerated well by the majority of participants. No major complications were noted. Numbness (9.6%) and hematoma (2.3%) were the two minor complications noted, which fully resolved. Thus, the proposed biopsy technique can be considered safe with only minimal risk of adverse events. Adoption of the proposed method is expected to increase the sampling of the supraclavicular BAT depot for r...

Research paper thumbnail of Uncoupled skeletal muscle mitochondria contribute to hypermetabolism in severely burned adults

American journal of physiology. Endocrinology and metabolism, 2014

Elevated metabolic rate is a hallmark of the stress response to severe burn injury. This response... more Elevated metabolic rate is a hallmark of the stress response to severe burn injury. This response is mediated in part by adrenergic stress and is responsive to changes in ambient temperature. We hypothesize that uncoupling of oxidative phosphorylation in skeletal muscle mitochondria contributes to increased metabolic rate in burn survivors. Here, we determined skeletal muscle mitochondrial function in healthy and severely burned adults. Indirect calorimetry was used to estimate metabolic rate in burn patients. Quadriceps muscle biopsies were collected on two separate occasions (11 ± 5 and 21 ± 8 days postinjury) from six severely burned adults (68 ± 19% of total body surface area burned) and 12 healthy adults. Leak, coupled, and uncoupled mitochondrial respiration was determined in permeabilized myofiber bundles. Metabolic rate was significantly greater than predicted values for burn patients at both time points (P < 0.05). Skeletal muscle oxidative capacity, citrate synthase act...

Research paper thumbnail of Acute amino acid intake does not alter mitochondrial function in older adults

Research paper thumbnail of The effect of acute oral amino acid intake on fatty acid oxidation

Research paper thumbnail of Severe thermal trauma alters adipose tissue mitochondrial function in children

Research paper thumbnail of Brown Adipose Tissue Improves Whole-Body Glucose Homeostasis and Insulin Sensitivity in Humans

Diabetes, 2014

Brown adipose tissue (BAT) has attracted scientific interest as an antidiabetic tissue owing to i... more Brown adipose tissue (BAT) has attracted scientific interest as an antidiabetic tissue owing to its ability to dissipate energy as heat. Despite a plethora of data concerning the role of BAT in glucose metabolism in rodents, the role of BAT (if any) in glucose metabolism in humans remains unclear. To investigate whether BAT activation alters whole-body glucose homeostasis and insulin sensitivity in humans, we studied seven BAT-positive (BAT(+)) men and five BAT-negative (BAT(-)) men under thermoneutral conditions and after prolonged (5-8 h) cold exposure (CE). The two groups were similar in age, BMI, and adiposity. CE significantly increased resting energy expenditure, whole-body glucose disposal, plasma glucose oxidation, and insulin sensitivity in the BAT(+) group only. These results demonstrate a physiologically significant role of BAT in whole-body energy expenditure, glucose homeostasis, and insulin sensitivity in humans, and support the notion that BAT may function as an antidiabetic tissue in humans.

Research paper thumbnail of Dietary Intake in Asthma and Atopy: A Pediatric Case-Control Study

Journal of the American Dietetic Association, 2011

Learning Outcome: Participants will be able to advise clients looking for ergogenic aids to consu... more Learning Outcome: Participants will be able to advise clients looking for ergogenic aids to consume whole beetroot, a healthy nitrate source, to improve running velocity.

Research paper thumbnail of Impact of Obesity on Body Image Dissatisfaction and Social Integration Difficulty in Adolescent and Young Adult Burn Injury Survivors

Journal of Burn Care & Research, 2013

Burn injury deformities and obesity have been associated with social integration difficulty and b... more Burn injury deformities and obesity have been associated with social integration difficulty and body image dissatisfaction. However, the combined effects of obesity and burn injury on social integration difficulty and body image dissatisfaction are unknown. Adolescent and young adult burn injury survivors were categorized as normal weight (n = 47) or overweight and obese (n = 21). Burn-related and anthropometric information were obtained from patients' medical records, and validated questionnaires were used to assess the main outcomes and possible confounders. Analysis of covariance and multiple linear regressions were performed to evaluate the objectives of this study. Obese and overweight burn injury survivors did not experience increased body image dissatisfaction (12 ± 4.3 vs 13.1 ± 4.4; P = .57) or social integration difficulty (17.5 ± 6.9 vs 15.5 ± 5.7; P = .16) compared with normal weight burn injury survivors. Weight status was not a significant predictor of social integration difficulty or body image dissatisfaction (P = .19 and P = .24, respectively). However, mobility limitations predicted greater social integration difficulty (P = .005) and body image dissatisfaction (P < .001), whereas higher weight status at burn was a borderline significant predictor of body image dissatisfaction (P = .05). Obese and overweight adolescents and young adults, who sustained major burn injury as children, do not experience greater social integration difficulty and body image dissatisfaction compared with normal weight burn injury survivors. Mobility limitations and higher weight status at burn are likely more important factors affecting the long-term social integration difficulty and body image dissatisfaction of these young people. (J Burn Care Res 2013;34:102-108)

Research paper thumbnail of An Obesity-Preventive Lifestyle Score Is Negatively Associated with Physician-Diagnosed Asthma: Results from a Pediatric Case-Control Study

Journal of the Academy of Nutrition and Dietetics, 2013