Comparison between Wright and Shukla formulas: which is better for the placement of umbilical catheters in newborns ≤ 1500 g?

BACKGROUND: Intravascular venous (VUC) or arterial (AUC) umbilical catheter placement is the most frequent invasive procedure in the neonatal intensive care unit (NICU). Either Wright's or Shukla's formula is used to introduce the catheters. However, Shukla's formula is associated with incorrect insertion, especially for newborns < 1500 g. This study aimed to determine by chest X-ray if Wright's formula is better than Shukla's formula for the correct placement of umbilical catheters in newborns ≤ 1500 g. METHODS: We included patients admitted to the NICU of a secondary-level hospital between 2021-2022 who received VUC or AUC through the Wright or Shukla formulas. RESULTS: A total of 129 newborns were included: 78 with VUC and 51 with AUC. In VUC, 50% with Wright and 36.8% with Shukla formulas had the correct location, (p = 0.24). In AUC, 56.6 % with Wright and 52.4% with Shukla formulas were placed correctly placed, (p = 0.76). VUC with weight < 1000 g were correctly placed in 36.4% with Wright and 33.3% with Shukla formulas (p = 0.58). VUC in newborns > 1000 g were correctly placed in 66.6% with Wright and 38.4% with Shukla formulas (p = 0.065). AUC in newborns < 1000 g were correctly placed in 45% using Wright and 42.9% Shukla formulas (p = 0.63). AUC in newborns > 1000 g were correctly placed in 80% using Wright and 57.1% Shukla formulas (p = 0.23). CONCLUSIONS: We found 13% more correctly placed VUC using Wright's formula. Moreover, Wright's formula was 29% above Shukla's VUC placement in neonates > 1000 g, although there was no significant difference due to the sample size.

INTRODUCCIÓN: La colocación de catéteres intravasculares venosos umbilicales (CVU) y arteriales (CAU) es el procedimiento invasivo más frecuente en la unidad de cuidados intensivos neonatales (UCIN). Para introducirlos se utilizan las fórmulas de Wright y de Shukla, aunque esta última podría estar asociada con una inserción incorrecta, especialmente en neonatos < 1500 g. El objetivo de este estudio fue determinar mediante radiografía de tórax cuál fórmula es mejor para la correcta colocación de catéteres umbilicales en recién nacidos ≤ 1500 g. MÉTODOS: Se incluyeron los pacientes ingresados en la UCIN de un hospital de segundo nivel entre 2021-2022 que recibieron CVU o CAU mediante las fórmulas de Wrigth o Shukla. RESULTADOS: Se incluyeron en total 129 recién nacidos: 78 CVU y 51 CAU. En CVU, Wright 50% y Shukla 36.8% tuvieron localización correcta, p = 0.24. En las CAU, Wright 56.6% y Shukla 52.4% tenían una ubicación correcta, p = 0.76. En CVU con peso < 1000 g, Wright 36.4% y Shukla 33.3% bien situados, p = 0.58. En CVU > 1000 g, Wright 66.6% y Shukla 38.4% bien situados, p = 0.065. En CAU < 1000 g, Wright 45% y Shukla 42.9%, p = 0.63. En CAU con peso > 1000 g, Wright 80% y Shukla 57.1%, p = 0.23. CONCLUSIONES: La colocación del CVU fue 13% mejor con la fórmula de Wright. La fórmula de Wright superó en el 29% la colocación del CVU en los neonatos > 1000 g en comparación con la de Shukla, aunque no hubo diferencia significativa debido al tamaño de la muestra.

Comparison between Wright and Shukla formulas: which is better for the placement of umbilical catheters in newborns ≤ 1500 g? / Comparación entre las fórmulas de Wright y de Shukla: ¿cuál es mejor para la colocación de catéteres umbilicales en recién nacidos ≤ 1500 g?

Abstract Background: Intravascular venous (VUC) or arterial (AUC) umbilical catheter placement is the most frequent invasive procedure in the neonatal intensive care unit (NICU). Either Wright's or Shukla's formula is used to introduce the catheters. However, Shukla's formula is associated with incorrect insertion, especially for newborns < 1500 g. This study aimed to determine by chest X-ray if Wright's formula is better than Shukla's formula for the correct placement of umbilical catheters in newborns ≤ 1500 g. Methods: We included patients admitted to the NICU of a secondary-level hospital between 2021-2022 who received VUC or AUC through the Wright or Shukla formulas. Results: A total of 129 newborns were included: 78 with VUC and 51 with AUC. In VUC, 50% with Wright and 36.8% with Shukla formulas had the correct location, (p = 0.24). In AUC, 56.6 % with Wright and 52.4% with Shukla formulas were placed correctly placed, (p = 0.76). VUC with weight < 1000 g were correctly placed in 36.4% with Wright and 33.3% with Shukla formulas (p = 0.58). VUC in newborns > 1000 g were correctly placed in 66.6% with Wright and 38.4% with Shukla formulas (p = 0.065). AUC in newborns < 1000 g were correctly placed in 45% using Wright and 42.9% Shukla formulas (p = 0.63). AUC in newborns > 1000 g were correctly placed in 80% using Wright and 57.1% Shukla formulas (p = 0.23). Conclusions: We found 13% more correctly placed VUC using Wright's formula. Moreover, Wright's formula was 29% above Shukla's VUC placement in neonates > 1000 g, although there was no significant difference due to the sample size.

Resumen Introducción: La colocación de catéteres intravasculares venosos umbilicales (CVU) y arteriales (CAU) es el procedimiento invasivo más frecuente en la unidad de cuidados intensivos neonatales (UCIN). Para introducirlos se utilizan las fórmulas de Wright y de Shukla, aunque esta última podría estar asociada con una inserción incorrecta, especialmente en neonatos < 1500 g. El objetivo de este estudio fue determinar mediante radiografía de tórax cuál fórmula es mejor para la correcta colocación de catéteres umbilicales en recién nacidos ≤ 1500 g. Métodos: Se incluyeron los pacientes ingresados en la UCIN de un hospital de segundo nivel entre 2021-2022 que recibieron CVU o CAU mediante las fórmulas de Wrigth o Shukla. Resultados: Se incluyeron en total 129 recién nacidos: 78 CVU y 51 CAU. En CVU, Wright 50% y Shukla 36.8% tuvieron localización correcta, p = 0.24. En las CAU, Wright 56.6% y Shukla 52.4% tenían una ubicación correcta, p = 0.76. En CVU con peso < 1000 g, Wright 36.4% y Shukla 33.3% bien situados, p = 0.58. En CVU > 1000 g, Wright 66.6% y Shukla 38.4% bien situados, p = 0.065. En CAU < 1000 g, Wright 45% y Shukla 42.9%, p = 0.63. En CAU con peso > 1000 g, Wright 80% y Shukla 57.1%, p = 0.23. Conclusiones: La colocación del CVU fue 13% mejor con la fórmula de Wright. La fórmula de Wright superó en el 29% la colocación del CVU en los neonatos > 1000 g en comparación con la de Shukla, aunque no hubo diferencia significativa debido al tamaño de la muestra.

Incidence of congenital and postnatal cytomegalovirus infection during the first year of life in Mexican preterm infants.

Cytomegalovirus infection occurs commonly during infancy. Postnatal infection in term infants is usually asymptomatic; however, infection in preterm infants can be associated with clinical manifestations during the neonatal period. Nevertheless, few studies to assess the frequency of cytomegalovirus infection in preterm infants have been performed outside of high-income countries. We analyzed the incidence of congenital and postnatal cytomegalovirus infection in a cohort of preterm infants. Cytomegalovirus infection was detected during the neonatal period in four of 178 infants; in three of them, the virus was detected during the first 3 weeks of life and, therefore, congenital infection was confirmed (1.7% incidence). Postnatal infection was detected in 44 (36.4%) of 121 infants who were assessed after discharge from the neonatal intensive care unit. Cytomegalovirus infection was significantly associated with the duration of breastfeeding. In addition, we characterized cytomegalovirus strains detected in infants together with sequences available at GenBank, based on sequences of the UL18 gene. Cytomegalovirus UL18-sequences clustered in five distinct clades (A-E), and sequences obtained from infants in our study were distributed in four of the five clades; 44.4% of these sequences were included in clade E. Breastfeeding duration was shorter on average (5.6 months) in infants with sequences in clade E compared to infants with sequences in the other three clades (8.2 months; p = .07). In conclusion, we provide information regarding the high incidence of cytomegalovirus infection in preterm infants. Further studies are warranted to assess if cytomegalovirus strain characteristics are associated with the risk of infection acquisition during infancy.

Changes in PPAR-γ Expression Are Associated with microRNA Profiles during Fetal Programming due to Maternal Overweight and Obesity.

BACKGROUND: There has been a global increase in the prevalence of obesity in pregnant women in recent years. Animal studies have shown that intrauterine environment associated with maternal obesity leads to epigenetic changes. However, the effects of epigenetic changes occurring before birth in response to maternal conditions have not been clearly characterized in humans. OBJECTIVE: The aim of the study was to analyze peroxisome proliferator-activated receptor (PPAR)-γ expression in cell cultures from newborns from mothers with overweight and obesity, in response to in vitro metabolic challenges and their relationship with microRNA profile and cytokine expression. Methods/Study design: The profile of circulating microRNAs from 72 mother-child pairs (including healthy infants born to normal weight [n = 35], overweight [n = 25], and obese [n = 12] mothers) was determined through real-time PCR, and the PPAR-γ expression in peripheral blood mononuclear cell cultures from offspring was analyzed after in vitro challenges. RESULTS: miR-146a, miR-155, and miR-378a were upregulated in overweight mothers, while miR-378a was upregulated in obese mothers compared to normal weight mothers. In children from overweight mothers, miR-155 and miR-221 were downregulated and miR-146a was upregulated, while offspring of mothers with obesity showed downregulation of miR-155, miR-221, and miR-1301. These microRNAs have direct or indirect relation with PPAR-γ expression. In vitro exposure to high triglyceride and exposure to miR-378a induced a higher expression of PPAR-γ in cells from offspring of mothers with overweight and obesity. In contrast, cells from offspring of mothers with obesity cultured with high glucose concentrations showed PPAR-γ downregulation. IL-1ß, IL-6, and TNF-α expression in cells of offspring of overweight and obese mothers differed from that of offspring of normal weight mothers. Limitation of our study is the small sample size. CONCLUSION: The blood microRNA profile, and in vitro PPAR-γ and inflammatory cytokine expression in cells of newborn infants are associated with maternal obesity indicating that epigenetic marks may be established during intrauterine development. Key Message: Neonatal microRNA profile is associated with maternal weight. Neonatal microRNA profile is independent of maternal microRNA profile. PPAR-γ expression in newborn cell cultures is affected by maternal weight.

Clinical impact and direct costs of nosocomial respiratory syncytial virus infections in the neonatal intensive care unit.

BACKGROUND: Nosocomial infections are a leading cause of morbidity, costs, and mortality in preterm newborns. Most reports regarding nosocomial infections in neonatal intensive care units (NICU) are focused on bacterial infections and there is limited information regarding the impact of nosocomial viruses. The objective of this study was to assess the impact of nosocomial respiratory syncytial virus (RSV) infections in a NICU. METHODS: This was a retrospective cohort design from a NICU in a general hospital in Mexico. We included 24 newborn infants with nosocomial RSV infection and 24 infants without RSV matched by gestational age, birth weight, and the period of time of hospitalization. RESULTS: Infants with nosocomial RSV infection had longer hospitalization duration (median 24 days vs. 13 days; P = .05), increased antibiotic use (45.8% vs. 8.3%; P = .003), more mechanical ventilation requirement (54.2% vs. 0.4%; P <.001), more frequent nosocomial infections (45.8% vs. 0%; P <.001), and higher hospitalization direct costs (median 3,587.20 USD vs. 1,123.60 USD; P = .001) after nosocomial RSV detection. CONCLUSIONS: Nosocomial RSV infections are associated to a significant increase of costs in infants hospitalized in the NICU. Evaluation of interventions that may reduce the incidence of nosocomial RSV infections in this setting is warranted.

Respiratory syncytial virus acute respiratory infection-associated hospitalizations in preterm Mexican infants: A cohort study.

BACKGROUND: Respiratory syncytial virus (RSV) is the leading cause of severe acute respiratory infections (ARI) in preterm infants. The incidence of RSV-associated hospitalizations has not been defined in Mexico. OBJECTIVES: To determine the incidence of ARI- and RSV-associated hospitalizations in preterm infants during the first year of life. METHODS: Prospective cohort study of 294 preterm infants followed up through monthly telephone calls and routine outpatient visits. Hospitalized children were identified through daily visits to pediatric wards of participating hospitals and through telephone calls. Respiratory samples were tested for RSV by RT-PCR. RESULTS: Mean gestational age of participating infants was 33 weeks. Ninety-six infants were diagnosed with bronchopulmonary dysplasia (BPD) and 17 with congenital heart disease (CHD); 11 had both conditions. There were 71 hospitalization episodes in 53 infants. Respiratory samples for RSV detection were available in 44 hospitalization episodes, and the result was positive in 16 (36.3%). At least one hospitalization for ARI was recorded in 33 of 96 participants with BPD, in seven of 17 with CHD, and 18 of 192 infants without these diagnoses. Five (71.4%) of CHD infants who required admission also had BPD. RSV-confirmed hospitalization rates were 9.4%, 5.9%, and 2.6% for infants with BPD, CHD, and otherwise healthy preterm infants, respectively. Attributable RSV admission frequencies were estimated to be 13.6%, 16.5%, and 4.1%, respectively. CONCLUSIONS: Mexican preterm infants, particularly those with BPD, have high rates of ARI- and RSVassociated hospitalizations. Specific interventions to reduce the incidence of severe infections in this highrisk group are required.

Correlation of perfusion index with patent ductus arteriosus repercussion in premature newborns.

Background: The ductus arteriosus is a necessary structure in fetal circulation, and its patency can produce hemodynamic alterations. The diagnostic gold standard is echocardiography, not always available. In the neonatal intensive care unit (NICU), they have pulse oximetry that measures perfusion index (PI), which could be used as a diagnostic tool in hemodynamically significant patent ductus arteriosus (HSPDA). Objective: The objective of the study was to correlate the PI increment (ΔPI) in 24 and 72 h after birth with HSPDA in premature newborns of NICU in a second-level hospital. Materials and methods: This is an analytic prospective study which included neonates of 26-34 weeks of gestational age, without comorbidities, who underwent echocardiography and measurement of PI in arm and leg, 24 and 72 h after birth. We did bivariate analysis with X2/exact Fisher's test and Student's t-test/Mann-Whitney U-test, besides Spearman correlation and linear regression for value prediction. Results: We included 39 premature newborns. We did not find significant differences between patients without and with HSPDA (median: 0.22 [0.06-0.58] vs. 0.03 [-0.27-0.2]; p = 0.09) at 24 h neither 72 h after birth (median: 0.2 [0-0.47] vs. 0.45 [-0.37-0.76]; p = 0.47). We found a positive correlation between ductus arteriosus diameter (DAD) and ΔPI (r: 0.78; confidence interval 95%: 0.6-0.88; p = 0.01). The prediction formula with linear regression is expressed this way: DAD = 1.31 + (2.05 × ΔIP). Conclusions: The PI does not allow us to discriminate between patient without and with HSPDA. The ΔPI could be a tool for the monitorization of DAD in neonates 72 h after birth.

Antecedentes: El conducto arterioso es una estructura necesaria en la circulación fetal, su persistencia puede provocar alteraciones hemodinámicas. El estándar de oro diagnóstico es la ecocardiografía, no siempre disponible. Las unidades de cuidados intensivos neonatales (UCIN) cuentan con oximetría de pulso, que mide el índice de perfusión (IP), el cual podría funcionar como auxiliar en el diagnóstico de persistencia del conducto arterioso hemodinámicamente significativo (PCAHs). Objetivo: Correlacionar el incremento del índice de perfusión (ΔIP) a las 24 y 72 h de vida extrauterina con PCAHs en recién nacidos prematuros de la UCIN de un hospital de segundo nivel. Materials y métodos: Estudio de cohorte analítico prospectivo donde se incluyeron neonatos de 26 a 34 semanas de gestación, sin comorbilidades, a quienes se les realizó ecocardiograma y medición de IP en brazo y pierna a las 24 y 72 h. Se efectuó análisis bivariante con Y2/prueba exacta de Fisher y t de Student/U de Mann-Whitney, además correlación de Spearman y regresión lineal para predicción de valores. Resultados: Se incluyeron 39 prematuros. No se encontró diferencia significativa entre los pacientes sin y con PCAHs (mediana: 0.22 [0.06, 0.58] vs. 0.03 [­0.27, 0.2]; p = 0.09) a las 24 h de vida y tampoco a las 72 h de vida (mediana: 0.2 [0, 0.47] vs. 0.45 [­0.37, 0.76], p = 0.47). Se encontró una correlación positiva entre el diámetro del conducto arterioso (DCA) y el ΔIP (r: 0.78; IC 95%: 0.60-0.88; p = 0.01). La fórmula de predicción por regresión lineal se expresa así: DCA = 1.31 + (2.05 x ΔIP). Conclusiones: El IP no permite discriminar entre pacientes sin y con PCAHs. El ΔIP podría ser una herramienta para la monitorización del diámetro del conducto en neonatos después de las 72 h de vida.

Correlación del índice de perfusión con la repercusión del conducto arterioso en prematuros.

Background: The ductus arteriosus is a necessary structure in fetal circulation, and its patency can produce hemodynamic alterations. The diagnostic gold standard is echocardiography, not always available. In the neonatal intensive care unit (NICU) they have pulse oximetry that measures perfusion index (PI), which could be used as a diagnostic tool in hemodynamic significant patent ductus arteriosus (HSPDA). Objective: To correlate the perfusion index increment (ΔPI) in 24 and 72 h after birth with HSPDA in premature newborns of NICU in a second level hospital. Materials and methods: This is an analytic prospective study which included neonates of 26-34 weeks of gestational age, without comorbidities, who underwent echocardiography and measurement of PI in arm and leg, 24 and 72 h after birth. We did bivariate analysis with Y2/exact Fisher test and Student t-test/Mann-Whitney U test, besides Spearman correlation and linear regression for value prediction. Results: We included 39 premature newborns. We did not find significant differences between patients without and with HSPDA (Median: 0.22 [0.06-0.58] vs. 0.03 [-0.27-0.2]; p = 0.09) at 24 h neither 72 h after birth (Median: 0.2 [0-0.47] vs. 0.45 [-0.37-0.76]; p = 0.47). We found a positive correlation between ductus arteriosus diameter (DAD) and ΔPI (r: 0.78; CI 95%: 0.6-0.88; p = 0.01). The prediction formula with linear regression is expressed this way: DAD = 1.31 + (2.05 x ΔIP). Conclusions: The PI doesn´t allow us to discriminate between patient without and with HSPDA. The ΔPI could be a tool for the monitorization of DAD in neonates 72 h after birth.

Antecedentes: El conducto arterioso es una estructura necesaria en la circulación fetal, su persistencia puede provocar alteraciones hemodinámicas. El estándar de oro diagnóstico es la ecocardiografía, no siempre disponible. Las unidades de cuidados intensivos neonatales (UCIN) cuentan con oximetría de pulso, que mide el índice de perfusión (IP), el cual podría funcionar como auxiliar en el diagnóstico de persistencia del conducto arterioso hemodinámicamente significativo (PCAHs). Objetivo: Correlacionar el incremento del índice de perfusión (ΔIP) a las 24 y 72 h de vida extrauterina con PCAHs en recién nacidos prematuros de la UCIN de un hospital de segundo nivel. Material y métodos: Estudio de cohorte analítico prospectivo donde se incluyeron neonatos de 26 a 34 semanas de gestación, sin comorbilidades, a quienes se les realizó ecocardiograma y medición de IP en brazo y pierna a las 24 y 72 h. Se efectuó análisis bivariante con Y2/prueba exacta de Fisher y t de Student/U de Mann-Whitney, además correlación de Spearman y regresión lineal para predicción de valores. Resultados: Se incluyeron 39 prematuros. No se encontró diferencia significativa entre los pacientes sin y con PCAHs (mediana: 0.22 [0.06, 0.58] vs. 0.03 [­0.27, 0.2]; p = 0.09) a las 24 h de vida y tampoco a las 72 h de vida (mediana: 0.2 [0, 0.47] vs. 0.45 [­0.37, 0.76], p = 0.47). Se encontró una correlación positiva entre el diámetro del conducto arterioso (DCA) y el ΔIP (r: 0.78; IC 95%: 0.60-0.88; p = 0.01). La fórmula de predicción por regresión lineal se expresa así: DCA = 1.31 + (2.05 x ΔIP). Conclusiones: El IP no permite discriminar entre pacientes sin y con PCAHs. El ΔIP podría ser una herramienta para la monitorización del diámetro del conducto en neonatos después de las 72 h de vida.

Correlación del índice de perfusión con la repercusión del conducto arterioso en prematuros / Correlation of perfusion index with patent ductus arteriosus repercussion in premature newborns

Resumen Antecedentes: El conducto arterioso es una estructura necesaria en la circulación fetal, su persistencia puede provocar alteraciones hemodinámicas. El estándar de oro diagnóstico es la ecocardiografía, no siempre disponible. Las unidades de cuidados intensivos neonatales (UCIN) cuentan con oximetría de pulso, que mide el índice de perfusión (IP), el cual podría funcionar como auxiliar en el diagnóstico de persistencia del conducto arterioso hemodinámicamente significativo (PCAHs). Objetivo: Correlacionar el incremento del índice de perfusión (ΔIP) a las 24 y 72 h de vida extrauterina con PCAHs en recién nacidos prematuros de la UCIN de un hospital de segundo nivel. Material y métodos: Estudio de cohorte analítico prospectivo donde se incluyeron neonatos de 26 a 34 semanas de gestación, sin comorbilidades, a quienes se les realizó ecocardiograma y medición de IP en brazo y pierna a las 24 y 72 h. Se efectuó análisis bivariante con Y2/prueba exacta de Fisher y t de Student/U de Mann-Whitney, además correlación de Spearman y regresión lineal para predicción de valores. Resultados: Se incluyeron 39 prematuros. No se encontró diferencia significativa entre los pacientes sin y con PCAHs (mediana: 0.22 [0.06, 0.58] vs. 0.03 [–0.27, 0.2]; p = 0.09) a las 24 h de vida y tampoco a las 72 h de vida (mediana: 0.2 [0, 0.47] vs. 0.45 [–0.37, 0.76], p = 0.47). Se encontró una correlación positiva entre el diámetro del conducto arterioso (DCA) y el ΔIP (r: 0.78; IC 95%: 0.60-0.88; p = 0.01). La fórmula de predicción por regresión lineal se expresa así: DCA = 1.31 + (2.05 x ΔIP). Conclusiones: El IP no permite discriminar entre pacientes sin y con PCAHs. El ΔIP podría ser una herramienta para la monitorización del diámetro del conducto en neonatos después de las 72 h de vida.

Abstract Background: The ductus arteriosus is a necessary structure in fetal circulation, and its patency can produce hemodynamic alterations. The diagnostic gold standard is echocardiography, not always available. In the neonatal intensive care unit (NICU) they have pulse oximetry that measures perfusion index (PI), which could be used as a diagnostic tool in hemodynamic significant patent ductus arteriosus (HSPDA). Objective: To correlate the perfusion index increment (ΔPI) in 24 and 72 h after birth with HSPDA in premature newborns of NICU in a second level hospital. Materials and methods: This is an analytic prospective study which included neonates of 26-34 weeks of gestational age, without comorbidities, who underwent echocardiography and measurement of PI in arm and leg, 24 and 72 h after birth. We did bivariate analysis with Y2/exact Fisher test and Student t-test/Mann-Whitney U test, besides Spearman correlation and linear regression for value prediction. Results: We included 39 premature newborns. We did not find significant differences between patients without and with HSPDA (Median: 0.22 [0.06-0.58] vs. 0.03 [–0.27-0.2]; p = 0.09) at 24 h neither 72 h after birth (Median: 0.2 [0-0.47] vs. 0.45 [–0.37-0.76]; p = 0.47). We found a positive correlation between ductus arteriosus diameter (DAD) and ΔPI (r: 0.78; CI 95%: 0.6-0.88; p = 0.01). The prediction formula with linear regression is expressed this way: DAD = 1.31 + (2.05 x ΔIP). Conclusions: The PI doesn´t allow us to discriminate between patient without and with HSPDA. The ΔPI could be a tool for the monitorization of DAD in neonates 72 h after birth.

Aluminum Contamination in Parenteral Nutrition Admixtures for Low-Birth-Weight Preterm Infants in Mexico.

BACKGROUND: Aluminum contamination from intravenous solutions still represents an unsolved clinical and biochemical problem. Increased aluminum intake constitutes a risk factor for the development to metabolic bone disease, anemia, cholestasis, and neurocognitive alterations. Low-birth-weight preterm infants (LBWPIs) are one of the most exposed populations for aluminum toxicity. METHODS: To determine the presence of aluminum in components employed in the preparation of parenteral nutrition (PN) admixtures in Mexico and compare with the maximal aluminum recommended intake from the Food and Drug Administration. RESULTS: Cysteine, trace elements, levocarnitine, phosphate, and calcium salts tested positive for aluminum contamination. All components analyzed were contained in glass vials. Total aluminum intake for 2 sample PN admixtures were calculated in basis to cover nutrition requirements of 2 hypothetical LBWPIs. Aluminum contents, stratified in micrograms per kilogram of weight, exceeded maximal aluminum recommendations, particularly for the very LBWPIs. Substituting sodium phosphate for potassium phosphate salts reduced aluminum intake by 52.7%. Calcium gluconate was the leading aluminum contamination source and confers the greatest risk for aluminum overdose, even with the salt substitution of potassium phosphate by sodium phosphate salts. Adding cysteine and trace elements might increase aluminum content in PN admixtures. CONCLUSION: Cysteine, trace elements, phosphate, and gluconate salts are the main sources of aluminum in PN prepared in Mexico. Substituting sodium phosphate for potassium phosphate salts reduces aluminum intake but does not resolve aluminum contamination risk. Mineral salts contained in plastic vials should be explored as an additional measure to reduce aluminum contamination.

NK cell immunophenotypic and genotypic analysis of infants with severe respiratory syncytial virus infection.

Respiratory syncytial virus (RSV) is the leading cause of severe lower respiratory tract infection in infants. Reduced numbers of NK cells have been reported in infants with severe RSV infection; however, the precise role of NK cells during acute RSV infection is unclear. In this study the NK and T cell phenotypes, LILRB1 gene polymorphisms and KIR genotypes of infants hospitalized with RSV infection were analyzed. Compared to controls, infants with acute RSV infection showed a higher proportion of LILRB1+ T cells; in addition, a subgroup of infants with RSV infection showed an increase in LILRB1+ NK cells. No differences in NKG2C, NKG2A, or CD161 expression between RSV infected infants and controls were observed. LILRB1 genotype distribution of the rs3760860 A>G, and rs3760861 A>G single nucleotide polymorphisms differed between infants with RSV infection and healthy donors, whereas no differences in any of the KIR genes were observed. Our results suggest that LILRB1 participates in the pathogenesis of RSV infection. Further studies are needed to define the role of LILRB1+ NK in response to RSV and to confirm an association between LILRB1 polymorphisms and the risk of severe RSV infection.

Epidemiology of Bordetella pertussis in San Luis Potosí, Mexico.

We analyzed data from 147 patients with suspected pertussis in San Luis Potosí, Mexico. Bordetella pertussis was detected by real-time polymerase chain reaction in 59 (40.1%) cases. The incidence of B. pertussis infection was 2.3 per 100,000 population. There were 6 deaths among the study patients. We conclude that the impact of pertussis in our state is significantly higher than previously estimated.