Shimon Barak - Academia.edu (original) (raw)

Papers by Shimon Barak

Research paper thumbnail of Entrustable Professional Activities for the Training of Postgraduate Primary Care Pediatricians

Research paper thumbnail of Absence seizures associated with bicarbonate therapy and normal serum pH

JAMA: The Journal of the American Medical Association, 1989

To the Editor.— Renal tubular acidosis is known to cause failure to thrive. 1,2 We found that tre... more To the Editor.— Renal tubular acidosis is known to cause failure to thrive. 1,2 We found that treating children with this condition by oral administration of sodium bicarbonate is both beneficial and benign. Report of a Case.— A 2 1/2-year-old girl with failure to thrive and weight and height below the third percentile for her age was referred to our department. Extensive investigation revealed metabolic acidosis (pH, 7.3 to 7.33), with hypocarbonemia of 16 to 18 mEq/L and hyperchloremia of 116 to 117 mmol/L. After excluding other causes, a presumptive diagnosis of renal tubular acidosis was made and oral therapy with 4 mEq/kg per day of sodium bicarbonate was instituted. This raised her blood pH level to 7.41 to 7.43 and enabled the child to attain the 10th percentile of weight and height for her age. A month later, the child experienced four episodes of absencelike seizures. There was no

Research paper thumbnail of SARS-CoV-2 Vaccination in Children and Adolescents—A Joint Statement of the European Academy of Paediatrics and the European Confederation for Primary Care Paediatricians

Frontiers in Pediatrics, 2021

Stopping the COVID-19 pandemic and its socio-economic consequences is only possible with a multif... more Stopping the COVID-19 pandemic and its socio-economic consequences is only possible with a multifaceted strategy, including mass vaccination. Studies have been conducted mainly in adults, and data on the pediatric population is relatively limited. However, it appears that vaccination in children and adolescents is highly effective and safe. Despite the apparent benefits of vaccinating this age group, there are some medical and ethical concerns. Based on the above considerations, the European Academy of Paediatrics (EAP) and the European Confederation of Primary Care Pediatricians (ECPCP) assessed the current situation and presented recommendations for international and national authorities, pediatricians, and pediatric societies regarding vaccination against SARS-CoV-2 in children and adolescents.

Research paper thumbnail of Fat Content in Human Milk According to Duration of Lactation: In Reply

Pediatrics, 2006

weight of the infants. The macronutrient content of 2554 milk samples was measured by infrared an... more weight of the infants. The macronutrient content of 2554 milk samples was measured by infrared analysis. In Fig 1, the fat content according to the duration of lactation is presented. The data support the results of Mandel et al, because the mean fat content decreased from 37.3 g/L in the first month to 33.7 g/L in the fourth month, followed by an increase to 48.0 g/L in the 17th month. This is equivalent to the relative increase in the mean values of fat content between short and long durations of lactation reported by Mandel et al. In addition, after 17 months of lactation, we found that the fat content of the milk continued to increase. However, these measurements were performed on smaller numbers of milk samples that originated from only 11 mothers, and it should be noted that 87% of the samples came from 3 mothers. Apart from the positive association between the fat content of milk and the duration of lactation, for which we have no explanation, we also found that the fat content increased significantly with increasing maternal BMI and with the volume of milk delivered to the milk bank. Mandel et al did not observe the positive association between maternal BMI and fat content in breast milk. The mechanism underlying the association between BMI and fat content could be that the magnitude of fat stores in mothers with a high milk production influenced the fat content of the milk. In addition, in another study,3 we also identified a significant positive association between the fat content of breast milk 4 months after delivery and weight gain during pregnancy. Furthermore, this difference was even larger 5 months after delivery. We speculate that the size of the fat stores built up during pregnancy as energy depots to support lactation can affect the fat concentration in breast milk. We do not know if this can also explain the increase in fat content observed during late lactation.

Research paper thumbnail of Fat and Energy Contents of Expressed Human Breast Milk in Prolonged Lactation

PEDIATRICS, 2005

Objective. To estimate fat and energy contents of human milk during prolonged lactation. Methods.... more Objective. To estimate fat and energy contents of human milk during prolonged lactation. Methods. Thirty-four mothers, of term, healthy, growing children, who had been lactating for >1 year (12–39 months) were recruited. Control subjects were 27 mothers, of term infants, who had been lactating for 2 to 6 months. Fat contents of the milk samples were estimated as creamatocrit (CMT) levels. Energy contents of the milk were measured with a bomb calorimeter. Results. The groups did not differ in terms of maternal height and diet, infant birth weight, gestational age, or breastfeeding frequency. They differed significantly in terms of maternal age, maternal weight, and BMI. The mean CMT levels were 7.36 ± 2.65% in the short-duration group and 10.65 ± 5.07% in the long-lactation group. The mean energy contents were 3103.7 ± 863.2 kJ/L in the short-duration group and 3683.2 ± 1032.2 kJ/L in the long-duration group. The mean CMT levels and mean energy contents were correlated significant...

Research paper thumbnail of Improve the primary pediatric care in Europe

Research paper thumbnail of Lactation Fat and Energy Contents of Expressed Human Breast Milk in Prolonged Fat and Energy Contents of Expressed Human Breast Milk in Prolonged Lactation Laboratory Methods

ABSTRACT. Objective. To estimate fat and energy contents of human milk during prolonged lactation... more ABSTRACT. Objective. To estimate fat and energy contents of human milk during prolonged lactation. Methods. Thirty-four mothers, of term, healthy, growing children, who had been lactating for >1 year (12-39 months) were recruited. Control subjects were 27 mothers, of term infants, who had been lactating for 2 to 6 months. Fat contents of the milk samples were estimated as creamatocrit (CMT) levels. Energy contents of the milk were measured with a bomb calorimeter. Results. The groups did not differ in terms of maternal height and diet, infant birth weight, gestational age, or breastfeeding frequency. They differed significantly in terms of maternal age, maternal weight, and BMI. The mean CMT levels were 7.36 ؎ 2.65% in the short-duration group and 10.65 ؎ 5.07% in the long-lactation group. The mean energy contents were 3103.7 ؎ 863.2 kJ/L in the short-duration group and 3683.2 ؎ 1032.2 kJ/L in the long-duration group. The mean CMT levels and mean energy contents were correlated s...

Research paper thumbnail of EAP and ECPCP Statement Risks for Children's Health During the COVID-19 Pandemic and a Call for Maintenance of Essential Pediatric Services

Frontiers in Pediatrics

The COVID-19 pandemic and global lockdown have had drastic socioeconomic and psychological effect... more The COVID-19 pandemic and global lockdown have had drastic socioeconomic and psychological effects on countries and people, respectively. There has been limited access to health care and education. These negative consequences have had a significant impact on the well-being of children and adolescents. Therefore, the EAP and the ECPCP are requesting state, health, and education authorities as well as European pediatric societies and the healthcare professionals that special attention be given to this population and the problems they face as a result of the pandemic.

Research paper thumbnail of A Benign Cause of Intermittent Bradycardia of Prematurity

American Journal of Diseases of Children, Mar 1, 1989

Research paper thumbnail of A Benign Cause of Intermittent Bradycardia of Prematurity

American Journal of Diseases of Children, Mar 1, 1989

Research paper thumbnail of European Pediatricians: Speaking with One Voice to Advocate for Children and Their Health

The Journal of Pediatrics

Research paper thumbnail of Improving paediatric care in the community

Research paper thumbnail of On the Mechanism of Sphingomyelin Interaction with Solubilized Membrane Proteins

Molecular Membrane Biology, 1987

Studies on the high-affinity receptor for IgE from rat basophilic leukemia cells (RBL-2H3) have s... more Studies on the high-affinity receptor for IgE from rat basophilic leukemia cells (RBL-2H3) have shown that the phospholipid sphingomyelin remains attached to the protein complex during washing of the affinity immobilized complex under solubilizing conditions. Here we extended these findings and compared the species distribution patterns in sphingomyelin and phosphatidylcholine of the receptor-bound lipids to those of the plasma membrane lipids. FC epsilon-receptor-bound sphingomyelin but not phosphatidylcholine was enriched in long-chain fatty acids. We then examined other membrane proteins with respect to sphingomyelin enrichment. RBL-2H3 cell surface proteins, immobilized on concanavalin A-Sepharose and washed under solubilizing conditions, also showed a two- to six-fold enrichment in the associated sphingomyelin. Similar observations were also derived from other cell types, such as the mouse fibroblast cell line A-9 and the pig kidney epithelial cell line PK-1. Since this has been observed in all the three cell sources, it was suggested that sphingomyelin enrichment in FC epsilon-receptor preparations, although reproducible, was not specific for this protein. That this phenomenon was not specific for a particular protein might also be concluded from experiments that have shown nonhomogenous distribution of sphingomyelin in protein-free lipid-detergent mixtures. These results are compatible with a model whereby the interaction between sphingomyelin and soluble membrane proteins results from preference to nonmicellar phases or to structures with extended hydrophobic domains, probably due to the imperfect fitness of the detergent micelles to properly accomodate these lipids. This feature makes long-chain sphingomyelin a plausible candidate for the lipid responsible for the stabilizing effect that crude lipid preparations exert on the structural and functional properties of some membrane protein, e.g., FC epsilon R.

Research paper thumbnail of Antenatal Diagnosis of Bilateral Congenital Chylothorax with Pericardial Effusion

Acta Obstetricia et Gynecologica Scandinavica, 1985

... CASE REPORT ANTENATAL DIAGNOSIS OF BILATERAL CONGENITAL CHYLOTHORAX WITH PERICARDIAL EFFUSION... more ... CASE REPORT ANTENATAL DIAGNOSIS OF BILATERAL CONGENITAL CHYLOTHORAX WITH PERICARDIAL EFFUSION Ariel J. Jaffa, Shimon Barak, Nehemia Kaysar and M. Reuben Peyser ... JAMA 1982;248: 1360. Randolph JG, Gross RE. Congenital chylothorax. ...

Research paper thumbnail of Fat and Energy Contents of Expressed Human Breast Milk in Prolonged Lactation

PEDIATRICS, 2005

To estimate fat and energy contents of human milk during prolonged lactation. Thirty-four mothers... more To estimate fat and energy contents of human milk during prolonged lactation. Thirty-four mothers, of term, healthy, growing children, who had been lactating for >1 year (12-39 months) were recruited. Control subjects were 27 mothers, of term infants, who had been lactating for 2 to 6 months. Fat contents of the milk samples were estimated as creamatocrit (CMT) levels. Energy contents of the milk were measured with a bomb calorimeter. The groups did not differ in terms of maternal height and diet, infant birth weight, gestational age, or breastfeeding frequency. They differed significantly in terms of maternal age, maternal weight, and BMI. The mean CMT levels were 7.36 +/- 2.65% in the short-duration group and 10.65 +/- 5.07% in the long-lactation group. The mean energy contents were 3103.7 +/- 863.2 kJ/L in the short-duration group and 3683.2 +/- 1032.2 kJ/L in the long-duration group. The mean CMT levels and mean energy contents were correlated significantly with the duration of lactation (R2 = 0.22 and R2 = 0.23, respectively). In multivariate regression analysis, CMT levels (or energy contents) were not influenced by maternal age, diet, BMI, or number of daily feedings but remained significantly influenced by the duration of lactation. Human milk expressed by mothers who have been lactating for >1 year has significantly increased fat and energy contents, compared with milk expressed by women who have been lactating for shorter periods. During prolonged lactation, the fat energy contribution of breast milk to the infant diet might be significant.

Research paper thumbnail of Entrustable Professional Activities for the Training of Postgraduate Primary Care Pediatricians

Research paper thumbnail of Absence seizures associated with bicarbonate therapy and normal serum pH

JAMA: The Journal of the American Medical Association, 1989

To the Editor.— Renal tubular acidosis is known to cause failure to thrive. 1,2 We found that tre... more To the Editor.— Renal tubular acidosis is known to cause failure to thrive. 1,2 We found that treating children with this condition by oral administration of sodium bicarbonate is both beneficial and benign. Report of a Case.— A 2 1/2-year-old girl with failure to thrive and weight and height below the third percentile for her age was referred to our department. Extensive investigation revealed metabolic acidosis (pH, 7.3 to 7.33), with hypocarbonemia of 16 to 18 mEq/L and hyperchloremia of 116 to 117 mmol/L. After excluding other causes, a presumptive diagnosis of renal tubular acidosis was made and oral therapy with 4 mEq/kg per day of sodium bicarbonate was instituted. This raised her blood pH level to 7.41 to 7.43 and enabled the child to attain the 10th percentile of weight and height for her age. A month later, the child experienced four episodes of absencelike seizures. There was no

Research paper thumbnail of SARS-CoV-2 Vaccination in Children and Adolescents—A Joint Statement of the European Academy of Paediatrics and the European Confederation for Primary Care Paediatricians

Frontiers in Pediatrics, 2021

Stopping the COVID-19 pandemic and its socio-economic consequences is only possible with a multif... more Stopping the COVID-19 pandemic and its socio-economic consequences is only possible with a multifaceted strategy, including mass vaccination. Studies have been conducted mainly in adults, and data on the pediatric population is relatively limited. However, it appears that vaccination in children and adolescents is highly effective and safe. Despite the apparent benefits of vaccinating this age group, there are some medical and ethical concerns. Based on the above considerations, the European Academy of Paediatrics (EAP) and the European Confederation of Primary Care Pediatricians (ECPCP) assessed the current situation and presented recommendations for international and national authorities, pediatricians, and pediatric societies regarding vaccination against SARS-CoV-2 in children and adolescents.

Research paper thumbnail of Fat Content in Human Milk According to Duration of Lactation: In Reply

Pediatrics, 2006

weight of the infants. The macronutrient content of 2554 milk samples was measured by infrared an... more weight of the infants. The macronutrient content of 2554 milk samples was measured by infrared analysis. In Fig 1, the fat content according to the duration of lactation is presented. The data support the results of Mandel et al, because the mean fat content decreased from 37.3 g/L in the first month to 33.7 g/L in the fourth month, followed by an increase to 48.0 g/L in the 17th month. This is equivalent to the relative increase in the mean values of fat content between short and long durations of lactation reported by Mandel et al. In addition, after 17 months of lactation, we found that the fat content of the milk continued to increase. However, these measurements were performed on smaller numbers of milk samples that originated from only 11 mothers, and it should be noted that 87% of the samples came from 3 mothers. Apart from the positive association between the fat content of milk and the duration of lactation, for which we have no explanation, we also found that the fat content increased significantly with increasing maternal BMI and with the volume of milk delivered to the milk bank. Mandel et al did not observe the positive association between maternal BMI and fat content in breast milk. The mechanism underlying the association between BMI and fat content could be that the magnitude of fat stores in mothers with a high milk production influenced the fat content of the milk. In addition, in another study,3 we also identified a significant positive association between the fat content of breast milk 4 months after delivery and weight gain during pregnancy. Furthermore, this difference was even larger 5 months after delivery. We speculate that the size of the fat stores built up during pregnancy as energy depots to support lactation can affect the fat concentration in breast milk. We do not know if this can also explain the increase in fat content observed during late lactation.

Research paper thumbnail of Fat and Energy Contents of Expressed Human Breast Milk in Prolonged Lactation

PEDIATRICS, 2005

Objective. To estimate fat and energy contents of human milk during prolonged lactation. Methods.... more Objective. To estimate fat and energy contents of human milk during prolonged lactation. Methods. Thirty-four mothers, of term, healthy, growing children, who had been lactating for >1 year (12–39 months) were recruited. Control subjects were 27 mothers, of term infants, who had been lactating for 2 to 6 months. Fat contents of the milk samples were estimated as creamatocrit (CMT) levels. Energy contents of the milk were measured with a bomb calorimeter. Results. The groups did not differ in terms of maternal height and diet, infant birth weight, gestational age, or breastfeeding frequency. They differed significantly in terms of maternal age, maternal weight, and BMI. The mean CMT levels were 7.36 ± 2.65% in the short-duration group and 10.65 ± 5.07% in the long-lactation group. The mean energy contents were 3103.7 ± 863.2 kJ/L in the short-duration group and 3683.2 ± 1032.2 kJ/L in the long-duration group. The mean CMT levels and mean energy contents were correlated significant...

Research paper thumbnail of Improve the primary pediatric care in Europe

Research paper thumbnail of Lactation Fat and Energy Contents of Expressed Human Breast Milk in Prolonged Fat and Energy Contents of Expressed Human Breast Milk in Prolonged Lactation Laboratory Methods

ABSTRACT. Objective. To estimate fat and energy contents of human milk during prolonged lactation... more ABSTRACT. Objective. To estimate fat and energy contents of human milk during prolonged lactation. Methods. Thirty-four mothers, of term, healthy, growing children, who had been lactating for >1 year (12-39 months) were recruited. Control subjects were 27 mothers, of term infants, who had been lactating for 2 to 6 months. Fat contents of the milk samples were estimated as creamatocrit (CMT) levels. Energy contents of the milk were measured with a bomb calorimeter. Results. The groups did not differ in terms of maternal height and diet, infant birth weight, gestational age, or breastfeeding frequency. They differed significantly in terms of maternal age, maternal weight, and BMI. The mean CMT levels were 7.36 ؎ 2.65% in the short-duration group and 10.65 ؎ 5.07% in the long-lactation group. The mean energy contents were 3103.7 ؎ 863.2 kJ/L in the short-duration group and 3683.2 ؎ 1032.2 kJ/L in the long-duration group. The mean CMT levels and mean energy contents were correlated s...

Research paper thumbnail of EAP and ECPCP Statement Risks for Children's Health During the COVID-19 Pandemic and a Call for Maintenance of Essential Pediatric Services

Frontiers in Pediatrics

The COVID-19 pandemic and global lockdown have had drastic socioeconomic and psychological effect... more The COVID-19 pandemic and global lockdown have had drastic socioeconomic and psychological effects on countries and people, respectively. There has been limited access to health care and education. These negative consequences have had a significant impact on the well-being of children and adolescents. Therefore, the EAP and the ECPCP are requesting state, health, and education authorities as well as European pediatric societies and the healthcare professionals that special attention be given to this population and the problems they face as a result of the pandemic.

Research paper thumbnail of A Benign Cause of Intermittent Bradycardia of Prematurity

American Journal of Diseases of Children, Mar 1, 1989

Research paper thumbnail of A Benign Cause of Intermittent Bradycardia of Prematurity

American Journal of Diseases of Children, Mar 1, 1989

Research paper thumbnail of European Pediatricians: Speaking with One Voice to Advocate for Children and Their Health

The Journal of Pediatrics

Research paper thumbnail of Improving paediatric care in the community

Research paper thumbnail of On the Mechanism of Sphingomyelin Interaction with Solubilized Membrane Proteins

Molecular Membrane Biology, 1987

Studies on the high-affinity receptor for IgE from rat basophilic leukemia cells (RBL-2H3) have s... more Studies on the high-affinity receptor for IgE from rat basophilic leukemia cells (RBL-2H3) have shown that the phospholipid sphingomyelin remains attached to the protein complex during washing of the affinity immobilized complex under solubilizing conditions. Here we extended these findings and compared the species distribution patterns in sphingomyelin and phosphatidylcholine of the receptor-bound lipids to those of the plasma membrane lipids. FC epsilon-receptor-bound sphingomyelin but not phosphatidylcholine was enriched in long-chain fatty acids. We then examined other membrane proteins with respect to sphingomyelin enrichment. RBL-2H3 cell surface proteins, immobilized on concanavalin A-Sepharose and washed under solubilizing conditions, also showed a two- to six-fold enrichment in the associated sphingomyelin. Similar observations were also derived from other cell types, such as the mouse fibroblast cell line A-9 and the pig kidney epithelial cell line PK-1. Since this has been observed in all the three cell sources, it was suggested that sphingomyelin enrichment in FC epsilon-receptor preparations, although reproducible, was not specific for this protein. That this phenomenon was not specific for a particular protein might also be concluded from experiments that have shown nonhomogenous distribution of sphingomyelin in protein-free lipid-detergent mixtures. These results are compatible with a model whereby the interaction between sphingomyelin and soluble membrane proteins results from preference to nonmicellar phases or to structures with extended hydrophobic domains, probably due to the imperfect fitness of the detergent micelles to properly accomodate these lipids. This feature makes long-chain sphingomyelin a plausible candidate for the lipid responsible for the stabilizing effect that crude lipid preparations exert on the structural and functional properties of some membrane protein, e.g., FC epsilon R.

Research paper thumbnail of Antenatal Diagnosis of Bilateral Congenital Chylothorax with Pericardial Effusion

Acta Obstetricia et Gynecologica Scandinavica, 1985

... CASE REPORT ANTENATAL DIAGNOSIS OF BILATERAL CONGENITAL CHYLOTHORAX WITH PERICARDIAL EFFUSION... more ... CASE REPORT ANTENATAL DIAGNOSIS OF BILATERAL CONGENITAL CHYLOTHORAX WITH PERICARDIAL EFFUSION Ariel J. Jaffa, Shimon Barak, Nehemia Kaysar and M. Reuben Peyser ... JAMA 1982;248: 1360. Randolph JG, Gross RE. Congenital chylothorax. ...

Research paper thumbnail of Fat and Energy Contents of Expressed Human Breast Milk in Prolonged Lactation

PEDIATRICS, 2005

To estimate fat and energy contents of human milk during prolonged lactation. Thirty-four mothers... more To estimate fat and energy contents of human milk during prolonged lactation. Thirty-four mothers, of term, healthy, growing children, who had been lactating for >1 year (12-39 months) were recruited. Control subjects were 27 mothers, of term infants, who had been lactating for 2 to 6 months. Fat contents of the milk samples were estimated as creamatocrit (CMT) levels. Energy contents of the milk were measured with a bomb calorimeter. The groups did not differ in terms of maternal height and diet, infant birth weight, gestational age, or breastfeeding frequency. They differed significantly in terms of maternal age, maternal weight, and BMI. The mean CMT levels were 7.36 +/- 2.65% in the short-duration group and 10.65 +/- 5.07% in the long-lactation group. The mean energy contents were 3103.7 +/- 863.2 kJ/L in the short-duration group and 3683.2 +/- 1032.2 kJ/L in the long-duration group. The mean CMT levels and mean energy contents were correlated significantly with the duration of lactation (R2 = 0.22 and R2 = 0.23, respectively). In multivariate regression analysis, CMT levels (or energy contents) were not influenced by maternal age, diet, BMI, or number of daily feedings but remained significantly influenced by the duration of lactation. Human milk expressed by mothers who have been lactating for >1 year has significantly increased fat and energy contents, compared with milk expressed by women who have been lactating for shorter periods. During prolonged lactation, the fat energy contribution of breast milk to the infant diet might be significant.