Effects of a valved infant-bottle with ergonomic teat on the coordination of sucking, swallowing, and respiration in late-preterm infants. The Safe Oral Feeding randomized Trial

Introduction

Breastfeeding naturally enables the coordination of sucking, swallowing, and respiration patterns for safe feeding. When breastfeeding is not possible a feeding device that releases milk in response to intra-oral vacuum could potentially offer improved coordination of sucking, swallowing, and breathing patterns compared to conventional devices. The aim of the study is to evaluate the effect of a valved infant-bottle with an ergonomic teat compared to a standard infant-bottle.

Methods

This unblinded randomized controlled trial focused on late preterm infants fed by bottle for at least three meals over the day, admitted to the Neonatal Unit of Sant'Anna Hospital (Turin, Italy). Infants were randomized to be fed with a valved infant-bottle with an ergonomic teat (B-EXP arm) or with a standard infant-bottle (B-STD arm). Monitoring included a simultaneous synchronized recording of sucking, swallowing and respiration. The main outcome was the swallowing/breathing ratio.

Results

Forty infants (20 B-EXP arm; 20 B-STD arm) with a median gestational age of 35.0 weeks (IQR 35.0-36.0 weeks) completed the study. Four infants were censored for the presence of artifacts in the polygraphic traces. The median swallowing/breathing ratio was 1.11 (1.03-1.23) in the B-EXP arm and 1.75 (1.21-2.06) in the B-STD (p = .003). A lower frequency of swallowing events during the inspiratory phase of breathing was observed in B-EXP arm compared with B-STD arm (p = 0.013).

Discussion

The valved infant-bottle with an ergonomic teat improves the coordination of sucking-swallowing-respiration and limits the risk of inhalation reducing the frequency of swallowing during the inspiratory phase.

Twinning as a risk factor for neonatal acute intestinal diseases: a case-control study

Introduction

Acute intestinal diseases (AID), including necrotizing enterocolitis and spontaneous intestinal perforation, are a group of conditions that typically present in preterm infants, and are associated with an elevated mortality and morbidity rate. The risk factors for these diseases remain largely unknown. The aim of the study is to identify the correlation between twinning and the development of AID.

Methods

A single-center retrospective case-control study was conducted. We recruited all infants with a diagnosis of AID, confirmed by anatomopathology, recovered in NICU between 2010 and 2020. Considering the rarity of the outcome, 4 matched controls for each subject were randomly chosen from the overall population of newborns. Odds Ratio (OR) and 95% Confidence Interval (CI) were calculated using a conditional logistic regression model and a multivariate model by the creation of a Directed Acyclic Graph (www.dagitty.net).

Results

The study population resulted in 65 cases and 260 controls. The two groups present similar median gestational age and mean birthweight in grams. The cases have a higher frequency of neonatal pathology (defined as at least one of patent ductus arteriosus, early or late sepsis, severe respiratory distress) (84.6% vs. 51.9%), medically assisted procreation (33.8% vs. 18.8%) and periventricular leukomalacia (10.8% vs. 2.7%), and a lower frequency of steroids prophylaxis (67.7% vs. 86.9%). About 50% of cases needed surgery. The OR for the direct effect were difference from one using logistic regression booth without and with repeated measures statements: from 1.14 to 4.21 (p = .019) and from 1.16 to 4.29 (p = .016), respectively.

Conclusions

Our study suggests that twinning may be a risk factor for the development of AID. Due to the small number of cases observed, further studies on larger populations are needed.

Quality of life and long-term results in patients operated on for Esophageal Atresia

BACKGROUND

Esophageal atresia (EA) with or without tracheoesophageal fistula (TEF) represents the most severe entity among the foregut malformations, with patients at risk of chronic morbidity. This study aims to investigate on health-related quality of life (QoL) and long-term results in patients with EA.

METHODS

50 patients (30M, 20F, mean age: 14-year-old), among 82 patients operated from January 1995 to December 2005, answered the questionnaire. Two groups where compared: 8-12 years (A), 12-18 years (B). The survey investigated on 5 itmes: dysphagia; GERD; pulmonary affections (asthma, bronchitis, episodes of chronic cough during a year); growth and nutritional status (BMI); QoL scores. A control group of 50 healthy children was used.

RESULTS

42 type III AE (3 long-gap and 1 VACTER association). Median BMI was 18,72 (SD 3,38) (range: 30,52-12,80). In 22 pts BMI < 18,5. 19 pts were positive for dysphagia (EAT-10 score > = 3). A correlation was found between dysphagia and low BMI (Pearson 0,37). Dysphagia and low BMI were more diffuse in the younger population, while decreased in group B. 15 pts treated in their life for GERD (8 with medical therapy; 7 fundoplication). GerdQ test data showed only 4 pts with score > 6. GERD and dysphagia: 11 pts with GERD presented EAT-10 test > 3 (Pearson value confirmed this correlation: 0,59). Respiratory pathologies: 26 pts with positive anamnesis for chronic pulmonary affections (recurrent bronchitis in 21 pts; chronic cough in 15; the association of both in 12; 11 pts with asthma). PedsQL 4.0 median value was 15,4 (SD 10,1), control group value was 15,6 (SD 7,6); difference between the 2 groups was not statistically significant (p-value: 0,11). Correlation test for comparing high value of PedsQL and long-term complication in AE: the strongest association was with the dysphagia (Pearson: 0,55).

CONCLUSIONS

Dysphagia resulted the most disabling symptom in group A but swallowing function slightly improved with the growth. Generally, AE seems not heavily influence patients' QoL.

Dissecting Mechanoenzymatic Properties of Processive Myosins with Ultrafast Force-Clamp Spectroscopy

Ultrafast force-clamp spectroscopy (UFFCS) is a single molecule technique based on laser tweezers that allows the investigation of the chemomechanics of both conventional and unconventional myosins under load with unprecedented time resolution. In particular, the possibility to probe myosin motors under constant force right after the actin-myosin bond formation, together with the high rate of the force feedback (200 kHz), has shown UFFCS to be a valuable tool to study the load dependence of fast dynamics such as the myosin working stroke. Moreover, UFFCS enables the study of how processive and non-processive myosin-actin interactions are influenced by the intensity and direction of the applied force. By following this protocol, it will be possible to perform ultrafast force-clamp experiments on processive myosin-5 motors and on a variety of unconventional myosins. By some adjustments, the protocol could also be easily extended to the study of other classes of processive motors such as kinesins and dyneins. The protocol includes all the necessary steps, from the setup of the experimental apparatus to sample preparation, calibration procedures, data acquisition and analysis.

Gastrostomy Intraperitoneal Bumper Migration in a Three-Year-Old Child: A Rare Complication following Gastrostomy Tube Replacement

Feeding gastrostomy is used worldwide for adults and children with feeding impairment to obtain long-term enteral nutrition. Percutaneous endoscopic gastrostomy insertion is considered the gold standard, but after the first months requires gastrostomy tube replacement with a low-profile button. The replacement is known as an easy procedure, but several minor and major complications may occur during and after the manoeuvre. We describe intraperitoneal bumper migration in a 3-year-old boy, a rare complication following gastrostomy tube replacement, and we discuss the recent literature regarding similar cases.

An integrated in vitro and in situ study of kinetics of myosin II from frog skeletal muscle

A new efficient protocol for extraction and conservation of myosin II from frog skeletal muscle made it possible to preserve the myosin functionality for a week and apply single molecule techniques to the molecular motor that has been best characterized for its mechanical, structural and energetic parameters in situ.With the in vitro motility assay, we estimated the sliding velocity of actin on frog myosin II (VF) and its modulation by pH, myosin density, temperature (range 4-30◦C) and substrate concentration. VF was 8.88 ± 0.26 μms⁻¹ at 30.6◦C and decreased to 1.60 ± 0.09 μms⁻¹ at 4.5◦C. The in vitro mechanical and kinetic parameters were integrated with the in situ parameters of frog muscle myosin working in arrays in each half-sarcomere. By comparing VF with the shortening velocities determined in intact frog muscle fibres under different loads and their dependence on temperature, we found that VF is 40-50% less than the fibre unloaded shortening velocity (V0) at the same temperature and we determined the load that explains the reduced value of VF. With this integrated approach we could define fundamental kinetic steps of the acto-myosin ATPase cycle in situ and their relation with mechanical steps. In particular we found that at 5◦C the rate of ADP release calculated using the step size estimated from in situ experiments accounts for the rate of detachment of motors during steady shortening under low loads.

New techniques in linear and non-linear laser optics in muscle research

This review proposes a brief summary of two applications of lasers to muscle research. The first application (laser tweezers), is now a well-established technique in the field, adopted by several laboratories in the world and producing a constant stream of original data, fundamental for our improved understanding of muscle contraction at the level of detail that only single molecule measurements can provide. As an example of the power of this technique, here we focus on some recent results, revealing the performance of the working stroke in at least two distinct steps also in skeletal muscle myosin. A second laser-based technique described here is second-harmonic generation; the application of this technique to muscle research is very recent. We describe the main results obtained thus far in this area and the potentially remarkable impact that this technology may have in muscle research.

Two independent mechanical events in the interaction cycle of skeletal muscle myosin with actin

During skeletal muscle contraction, regular arrays of actin and myosin filaments slide past each other driven by the cyclic ATP-dependent interaction of the motor protein myosin II (the cross-bridge) with actin. The rate of the cross-bridge cycle and its load-dependence, defining shortening velocity and energy consumption at the molecular level, vary widely among different isoforms of myosin II. However, the underlying mechanisms remain poorly understood. We have addressed this question by applying a single-molecule approach to rapidly ( approximately 300 mus) and precisely ( approximately 0.1 nm) detect acto-myosin interactions of two myosin isoforms having large differences in shortening velocity. We show that skeletal myosin propels actin filaments, performing its conformational change (working stroke) in two steps. The first step ( approximately 3.4-5.2 nm) occurs immediately after myosin binding and is followed by a smaller step ( approximately 1.0-1.3 nm), which occurs much faster in the fast myosin isoform than in the slow one, independently of ATP concentration. On the other hand, the rate of the second phase of the working stroke, from development of the latter step to dissociation of the acto-myosin complex, is very similar in the two isoforms and depends linearly on ATP concentration. The finding of a second mechanical event in the working stroke of skeletal muscle myosin provides the molecular basis for a simple model of actomyosin interaction. This model can account for the variation, in different fiber types, of the rate of the cross-bridge cycle and provides a common scheme for the chemo-mechanical transduction within the myosin family.

Exploring molecular motors and switches at the single-molecule level

Single-molecule techniques have propelled an impressive number of biophysical studies during the last decade. From relatively simple video-microscopy techniques, to sophisticated manipulation and detection apparata, single-molecule techniques are capable of tracking the movements and the reaction trajectories of single enzymatic units. By observing microspheres attached to biomolecules it is possible to follow the motion of molecular motors, or to detect conformational "switching" induced by regulatory proteins. Micromanipulation tools like optical tweezers have been widely applied to understand the mechanisms of linear molecular motors, and have allowed the measurement of the elementary steps and the forces produced by several motor proteins, including myosin, kinesin, and dynein. New experimental assays based on magnetic or optical "wrenches," which are able to apply and detect torques on rotary motors and biopolymers, are opening new possibilities in this field. Here, established and emerging magneto-optical manipulation and video-tracking techniques are reviewed, in the perspective of single molecular motors and regulatory proteins studies.

Three-dimensional magneto-optic trap for micro-object manipulation

A magneto-optic trap for micro-objects is described. Magnetic beads were trapped by optical tweezers while being rotated by a new integrated magnetic manipulator. Rotation was achieved with eight electromagnets with tip-pole geometry. The time orbital potential technique was used to achieve rotation of magnetic beads. Trapping in three dimensions and rotation of magnetic beads on three axes are demonstrated with forces up to 230 pN and force momenta of up to 10(-16)N m . A position-detection apparatus based on an interferometric scheme provides nanometer sensitivities in a few milliseconds.

In progressive nephropathies, overload of tubular cells with filtered proteins translates glomerular permeability dysfunction into cellular signals of interstitial inflammation

Progression to end-stage renal failure is the final common pathway of many forms of glomerular disease, independent of the type of initial insult. Progressive glomerulopathies have in common persistently high levels of urinary protein excretion and tubulointerstitial lesions at biopsy. Among the cellular mechanisms that may determine progression regardless of etiology, the traffic of excess proteins filtered from glomerulus in renal tubule may have functional importance by initiating interstitial inflammation in the early phase of parenchymal injury. This study analyzes the time course and sites of protein accumulation and interstitial cellular infiltration in two different models of proteinuric nephropathies. In remnant kidneys after 5/6 renal mass ablation, albumin and IgG accumulation by proximal tubular cells was visualized in the early stage, preceding interstitial infiltration of MHC-II-positive cells and macrophages. By double-staining, infiltrates developed at or near tubules containing intracellular IgG or luminal casts. This relationship persisted thereafter despite more irregular distribution of infiltrate. Similar patterns were found in an immune model (passive Heymann nephritis), indicating that the interstitial inflammatory reaction develops at the sites of protein overload, regardless of the type of glomerular injury. Osteopontin was detectable in cells of proximal tubules congested with protein in both models at sites of interstitial infiltration, and by virtue of its chemoattractive action this is likely mediator of a proximal tubule-dependent inflammatory pathway in response to protein load. Protein overload of tubules is a key candidate process translating glomerular protein leakage into cellular signals of interstitial inflammation. Mechanisms underlying the proinflammatory response of tubular cells to protein challenge in diseased kidney should be explored, as well as ways of limiting protein reabsorption/deposition to prevent consequent inflammation and progressive disease.

Pharmacologic control of angiotensin II ameliorates renal disease while reducing renal TGF-beta in experimental mesangioproliferative glomerulonephritis

We evaluated the effect of blocking angiotensin II (AngII) on the development of proteinuria and glomerular injury in antithymocyte serum (ATS) glomerulonephritis. Disease was induced in Sprague-Dawley rats by a single intravenous injection of rabbit ATS. Three groups of rats were considered: group 1 (n = 13), ATS rats with no therapy; group 2 (n = 13), ATS rats treated with angiotensin-converting enzyme inhibitor (40 mg/L lisinopril in the drinking water); and group 3 (n = 13), ATS rats treated with AngII receptor antagonist (50 mg/L L-158,809 in the drinking water). Treatment started 3 hours after ATS injection and lasted 4 days. An additional group of control rats (group 4, n = 13) received preimmune serum. At day 4, ATS rats developed proteinuria (46+/-5 mg/d v control 12+/-1 mg/d; P < 0.01), which was prevented by both lisinopril and L-158,809 (14+/-0.2 mg/d and 15+/-1.6 mg/d, respectively, P < 0.01 v ATS). Systolic blood pressure was comparable in ATS rats and in controls (119+/-4 mm Hg v 120+/-2 mm Hg). Systolic blood pressure values were significantly decreased after either lisinopril or L-158,809 (104+/-3 mm Hg and 101+/-5 mm Hg, respectively; P < 0.01 v ATS). Serum creatinine levels were similar in all groups. Quantitation of proliferating cells and macrophages by analysis of proliferating cell nuclear antigen-positive and ED1-positive cells/glomerular cross-section showed a marked increase in proliferating cell nuclear antigen-positive cells in glomeruli of ATS rats over controls (12.6+/-0.5 cells/glomerular cross-section v 1.9+/-0.2 cells/glomerular cross-section; P < 0.01), which was significantly (P < 0.01) prevented by both treatments (lisinopril, 5.7+/-1.0 cells/glomerular cross-section; L-158,809, 4.8+/-1.5 cells/glomerular cross-section). The increase in ED1-positive cells (10+/-0.7 cells/glomerular cross-section v controls, 1.8+/-0.2 cells/glomerular cross-section; P < 0.01) was also significantly (P < 0.01) reduced by lisinopril and L-158,809 (4.1+/-0.7 cells/glomerular cross-sections and 2.6+/-0.6 cells/glomerular cross-section, respectively). Blocking of AngII activity prevented almost completely the formation of microaneurysms in ATS rats (percent of glomeruli with microaneurysms: ATS, 11.5%+/-3.5%; ATS + lisinopril, 0.4%+/-0.2%; ATS + L-158,809, 0.8%+/-0.8%; controls, 0%). Because AngII is a potent inducer of renal transforming growth factor-beta (TGF-beta), a cytokine involved in the regulation of cell proliferation, matrix deposition, and monocyte migration (which is overexpressed in the kidney of ATS rats), we then evaluated the effect of AngII inhibitors on renal gene expression of TGF-beta1 and on urinary TGF-beta1. TGF-beta1 mRNA levels in kidneys of ATS rats were 3.6-fold higher than those of controls and were reduced by 46% and 32% after treatment with lisinopril and L-158,809, respectively. Urinary TGF-beta1 excretion increased in ATS (37.3+/-6.0 ng/d v controls, 13.8+/-3.4 ng/d; P< 0.01) but was normalized by lisinopril and L-158,809 (7.6+/-1.9 ng/d and 6.4+/-0.4 ng/d, respectively; P < 0.01). Thus, in ATS, blocking AngII synthesis prevents proteinuria and reduces glomerular cell proliferation and inflammatory cell infiltration, possibly by reducing excessive renal TGF-beta synthesis. These findings may be relevant for future strategies in the treatment of human mesangioproliferative glomerulonephritis.

High mitochondrial sequence diversity in linguistic isolates of the Alps

Segment I of the control region of mtDNA (360 bases) was sequenced in seven samples, each of 10 individuals inhabiting villages in the eastern Italian Alps (South Tyrol and Trentino). Three linguistic groups, German, Italian, and Ladin, were represented by two samples each; the seventh sample comes from an isolated group of German origin, the Mocheni, who are linguistically distinct and geographically separated from the bulk of the German speakers. Seventy-four polymorphic sites were identified, defining 63 different haplotypes. Mocheni and Ladin speakers tend to form two clusters in the evolutionary trees inferred from sequences. Analysis of molecular variance shows significant differentiation within samples, among them, and among linguistic groups. Genetic differences between the Ladins and the other groups are not much smaller than between Europeans and some Africans; variation is large within groups, as well, with the exception of only the Mocheni. In the evolutionary trees where the four alpine groups are compared with other European populations, Mocheni and especially Ladins appear as clear outliers. Romansch-speaking Swiss, who are linguistically related to Ladins, are not genetically similar to them, for this segment of DNA. Because the time elapsed since colonization of the Alps (< or = 12,000 years) is short in mutational terms, the only model accounting for the observed relationships between mtDNA variation and linguistic identity seems one in which a population ancestral to Ladin speakers was already differentiated long before the Alps were settled and the current linguistic affiliations were established. For the Mocheni, the results are consistent with a simpler episode of allele loss, from an original genetic pool common to the ancestors of the current German speakers.

Survival of an infant with pulmonary hypoplasia treated with dexamethasone

Pulmonary hypoplasia is lethal in its most severe form; in less severe cases the clinical course is protracted, usually resulting in chronic lung disease. A case of unexpected survival of an infant with clinical and radiologic evidence of pulmonary hypoplasia, in whom dexamethasone was administered, is presented. Possible mechanisms of dexamethasone's influence on outcome are discussed.

Postoperative evaluation of complex congenital heart disease by magnetic resonance imaging

This study suggests that the use of MRI together with echocardiography may reduce the need for serial cardiac catheterizations in the postoperative care of children with complex congenital heart disease.