Masendu Kalenga

Protein Deficiency and the Growing Rat Lung. I. Nutritional Findings and Related Lung Volumes

ABSTRACT: We investigated the consequences of early malnutrition on milk production by dams and on body weight and structural lung growth of young rats using two models of protein restriction. Dams of the early restriction group were fed an 8% casein diet starting at parturition. Those of the delayed restriction group received a 12% casein diet from lactation d 8–14 and thereafter the 8% diet. After weaning, early restriction and delayed restriction group rats were maintained on low protein until d 49, then refed the control diet (18% casein) up to d 126. Milk was analyzed on d 12. Animals were killed at d 21, 49, and 126 for lung fixation in situ. In this report, we show that protein restriction lowered milk yield to 38% of normal. Milk lipid per gram of dry weight tended to be increased, whereas lactose and protein were significantly decreased. Pups from protein-restricted dams grew less and had lower lung volumes, effects being more serious at d 49. However, specific lung volumes (in milliliters per 100 g body weight) were constantly increased. This means that lung was either less affected than body mass or overdistended due to less connective tissue. After refeeding, both groups showed a remarkable catch-up in growth with restoration of the normal allometric relationship between lung volume and body weight. Thus, even after an early onset of protein restriction to total body, the lung is still capable to substantially recover from growth retardation.

Protein deficiency and the growing rat lung. II: Morphometric analysis and morphology

ABSTRACT: Effects of protein deficiency during the whole period of postnatal development and intensive growth were studied in the rat lung parenchyma. Dams received a low protein diet as follows: early restriction, 8% casein diet from parturition, and delayed restriction, 12% then 8% casein diet from lactation d 8. After weaning (d 21), early restriction and delayed restriction group rats were maintained on the 8% casein diet until d 49, wherefrom they were returned to normal food (18% casein) for 11 wk. Lungs were processed for light and electron microscopic morphometry on d 21, 49, and 126. The diffusion capacity of the lung for O2 (DLO2) was also determined from the morphologic parameters. Volume and surface densities of the parenchymal components of malnourished rats did not consistently differ from controls. Because of lower lung volumes, absolute values, including DLO2, were all significantly decreased. Further, although lung volume growth was less impaired than body growth and thus deviated from the normal allometric relationship, most morphometric parameters paralleled body weight changes. Visually, we detected minor morphologic alterations at d 21 and 49, not necessarily reflected by morphometric data. But, importantly, lung parenchyma appeared mature at weaning despite the growth retardation. Normal refeeding resulted in a striking regrowth of the lung parenchyma. Although early restriction rats did not fully catch up in lung volume, most parenchymal parameters and DLO2 were largely restored in both refed groups.

Protein Deprivation from the Neonatal Period Impairs Lung Development in the Rat

ABSTRACT: The effects of early protein-deficiency on lung development were studied in the rat. Newborn male rats were nursed in groups of eight. Control dams and pups received a 15% protein diet during the whole experiment. Test mothers only received 12 and 8% proteins from the 7th and the 14th day of lactation. Test rats fed a diet of 8% protein were weaned at 21 days and maintained on the low protein diet for 1 month. This caused a marked decrease in body weight gain, but lung/body weight ratio was not affected. Lung DNA and protein content, lung protein concentration, but not lung DNA concentration were decreased, suggesting the presence of fewer and smaller cells than in control lungs. Volume-pressure curves were performed on excised lungs. With air-filling, the curve obtained in rats fed a diet with 8% proteins was shifted downward and to the right, even when expressed as percent of maximal volume. Its exponential analysis assessed a decrease in lung compliance. In contrast, with saline-filling, the recoil pressure was decreased in rats fed a diet with 8% proteins. Both with air and saline-filling, the pressure at lung rupture was increased in malnourished rats. It is concluded that protein-deficiency from the neonatal period increases surface forces, decreases tissue elastic forces, and augments resistance of the lung to rupture.

Nutritional Aspects of Lung Development

The relationship between nutrition and the respiratory system has been extensively explored during the last two decades, especially the potentially deleteri-ous effects of inadequate nutrition on lung structure and function. It is of special concern that in several clinical conditions undernutrition occurs during the most critical periods of normal lung restructuring. Nutritional perturbations are likely to interfere with cellular and extracellular functions, which in turn may impair lung growth and development and may eventually predispose to chronic lung diseases. Conversely, pulmonary diseases may increase nutritional requirements and also impede adequate nutrition supply.

Automated detection and classification of basic shapes of newborn cry melody

Abstract The study of newborn cry is a promising non-intrusive and cheap approach to support the early diagnosis of neurodevelopmental disorders. Specifically, cry melody, the trend of the fundamental frequency (f0) over time, could add relevant information to the acoustical analysis of infant crying. To date, the cry analysis is mainly performed by paediatricians/neurologists through a perceptual examination based on listening to the cry and visually inspecting the f0 shape. Therefore, this approach is not widespread as the procedure is operator-dependent and requires a considerable amount of time often prohibitive in daily clinical practice. This paper aims at providing a support to the perceptual analysis through a fully automated method for assessing the melodic shape of newborn cry. Cry units are detected within each recording, even of long duration, and their classification is performed according to five basic melodic shapes (falling, rising, symmetrical, plateau, and complex). The method is tested on synthesized signals and applied to recordings coming from at term healthy newborns. Results are compared to the perceptual analysis performed by trained raters with up to 98% matching. Being contact-less and cheap, this method is well suited for routinely clinical applications and could be effectively related to other clinical parameters for early detection of possible brain injuries or neuro-developmental disorders.

Mathematical bias in assessment of placental residual blood volume

We read with interest the randomized controlled trial by Mercer et al. Their study adds valuable information to the debated question of the ideal timing to clamp the cord for term infants. However, in their description of early outcomes, we consider that the formula used to evaluate the relative placental residual blood volume (rPRBV) is prone to ‘mathematical’ bias: as delayed cord clamping allows blood to be transfused from the placenta to the baby, the birth weight (BW) is increased by the intervention, as found in their report and previous studies. Therefore, using an intervention dependant-BW as a denominator to compute rPRBV (rPRBV= PRBV/BW) will amplify differences between immediate and delayed cord clamping groups. The sum of BW and absolute PRBV would not be affected by the timing of cord clamping; this sum could then be used as the fraction’s denominator (rPRBV = PRBV/(PRBV+BW)) to allow a more robust estimation of rPRBV difference. CONFLICT OF INTEREST

early respiratory changes after surfactant therapy in premature infants assisted by primary high frequency oscillatory ventilation (HFOV)

Early Respiratory changes after Surfactant Therapy in Premature Infants assisted by Primary High Frequency Oscillatory Ventilation (HFOV). 1684

The Once-Daily Concept of Aminoglycoside Administration adapted in Neonatology: The case for Amikacin 1455

Background:The bactericidal efficacy of Aminoglycosides (Ags) is directly related to peak (P) serum concentrations (C), particularly the first one. Transitory high C of Ags do not result in such a high-drug uptake by renal and cochlear tissues because of the saturation of cell binding sites. In most clinical practice using conventional schedule of Ags administration in sick neonates (N), pharmacokinetic profiles remain inadequate (low P and too elevated trough (T) C), which diminishs efficacy, increases risks of toxicity and emergence of bacterial resistance. Objective: Prospective evaluation of a new dosing-chart of Amikacin (Ak),based on a previous pharmacokinetic population study, in high risk N suspected of infection within the 2 first days of life. Study Design: 177 N (69 females and 108 males); mean gestational age (GA) ±1SD: 33.6 ± 4.1 Weeks (W) received Ak regimen dosage according to the following dosing-chart: Group (Gr) 1a GA 0.05) between the treated Gr and the corresponding non-treated control Gr. While the primary aim was not to test the bactericidal efficacy of this new regimen, the recovery was excellent in 37 N with proven or highly suspected infection. Conclusion:The proposed scheme of Ak Administration, even in high-risk N, allows to achieve adequate Ak P and T serum C (whatever the GA at birth), while drug-induced renal and cochlear toxicity is kept minimal. These serum C would allow for a P-Minimal Inhibitory Concentration (MIC) ratio ≥ 8 to be easily reached, which is now considered as optimal for Ags treatment.

high frequency oscillatory ventilation (HFOV) in neonatal respiratory distresse syndrome (RDS): effects of early lung volume optimization (LVO)

High Frequency Oscillatory Ventilation (HFOV) in Neonatal Respiratory Distress Syndrome (RDS): effects of early Lung Volume Optimization(LVO). 1522