Outcomes after tongue-lip adhesion or mandibular distraction osteogenesis in infants with Pierre Robin sequence and severe airway obstruction.

The objective was to review and compare outcomes after tongue-lip adhesion (TLA) and mandibular distraction osteogenesis (MDO) in infants with severe breathing difficulties related to Pierre Robin sequence (PRS). A single-centre retrospective (2002-2012) study was carried out; 18 infants with severe breathing difficulties related to PRS resistant to conservative treatment, who underwent TLA or MDO to correct airway obstruction, were enrolled. The primary outcome measures were successful weaning from respiratory support and resumption of full oral feeding. Nine underwent TLA and nine MDO. Eight of the nine infants who underwent MDO and all those treated with TLA were successfully weaned from respiratory support. After discharge, residual respiratory distress was diagnosed more commonly after TLA than after MDO (6/9 vs 1/9, P=0.050). Infants resumed oral feeding sooner after MDO than after TLA (mean days after surgery to full oral feeds 44±24 vs 217±134, P<0.003). The length of hospital stay was longer for infants treated with MDO than for those treated with TLA. The rate of complications was similar. Infants with severe airway obstruction related to PRS can benefit safely from either TLA or MDO. Although MDO lengthens the time to discharge, this option stabilizes airway patency of infants with PRS more efficiently and achieves full oral feeding more rapidly than TLA.

[Ventilatory care]. / L'assistenza ventilatoria.

Mechanical ventilation is considered a supportive, nontherapeutic technology used to perform the work of breathing for patients who are unable to do so on their own. In neonatology, mechanical ventilation is often used for premature neonates who are unable to sustain ventilation because of reduced functional residual capacity due to surfactant deficiency. Mechanical ventilation is thus an attempt to mimic the respiratory system's physiological function of gas exchange until the respiratory system reaches maturation. In pediatrics, mechanical ventilation is rarely used for acute respiratory distress syndrome as shown by Dahlem et al. in 2003 who found that only 9.9% of cases of respiratory failure in PICU was caused by ARDS. For this reason, ventilatory techniques in PICU are very heterogenous from the assisted to the most aggressive controlled modes associated with ventilator maneuvers. There are no specific guidelines for the use of mechanical ventilation in children and the low number of infants with ARDS in PICU makes it difficult to run randomized controlled trials in this population. Thus the algorithms are based on the results of either adult or neonatal studies. The advantage of extrapolating data from the neonatal evidence relates mainly to the prevention of ventilator induced lung injury (e.g., CPAP, HFOV, NIV, permissive hypercapnia, surfattant), of which neonatologists are particularly expert.

Transcranial Doppler for brain death in infants: the role of the fontanelles.

OBJECTIVE: Transcranial Doppler (TCD) is a sensitive technique for circulatory arrest diagnosis in brain death when patterns such as reverberant flow and short systolic spikes are observed. In infants, the nonossified fontanelles compensate for intracranial hypertension. We describe TCD patterns in infants with brain death, different from adults, with the hemodynamic modifications induced by anterior fontanelle compression. METHOD: TCD was performed in 2 infants with diagnosed brain death admitted to the neonatal intensive care unit. RESULTS: TCD showed a large peak 'reverberant' flow, with a high peak systolic velocity and a consistent retrograde component, away from the brain. Compression of the anterior fontanelle induced, at first, a reduction in systolic flow with the subsequent appearance of the characteristic short systolic spikes. Upon compression removal, a brief increase in the systolic flow was observed before the prompt reappearance of the reverberant flow. CONCLUSION: TCD for brain death diagnosis should be done cautiously in infants. In these cases, reverberating flow may be indicative of circulatory arrest even if with a large peak and with a high peak systolic velocity. Heavy fontanelle compression may reproduce the classical adult TCD patterns of brain death, thus supporting the diagnosis of cerebral circulatory arrest.

In vitro proliferation of achondroplastic and normal mouse chondrocytes, before and after basic fibroblast growth factor stimulation.

Achondroplasia in mice is a recessive genetic disorder, characterized by disproportionate dwarfism with reduced bone growth. The cause of this chondrodystrophy is unknown. In this study normal and achondroplastic mouse chondrocytes were cultured in monolayer primary culture, their differentiation was verified by immunofluorescence and their growth was compared. The results showed that achondroplastic cells exhibited a higher proliferative activity than control cells of the same age, confirmed also by a thymidine incorporation assay. Furthermore, basic fibroblast growth factor treatment was found to induce a strong increase in growth of normal mouse chondrocytes, while it did not stimulate statistically significant proliferation of achondroplastic mouse cells. We suppose that this different growth rate could play a role in achondroplastic phenotype development.

Induction of micronuclei in bone marrow by two pesticides and their differentiation with CREST staining: an in vivo study in mice.

Two pesticides, organophosphate phosphamidon (PHO) and organochlorine dieldrin (DED) were assayed by the mouse bone marrow micronucleus test, to ascertain whether they showed genotoxic activity in vivo. Two doses, sub-lethal (PHO=3 mg/kg b.wt.; DED=60 mg/kg b.wt.) and lethal (PHO=5 mg/kg b.wt.; DED=90 mg/kg b.wt.), of each substance were administered intraperitoneally to 9-10-week old CBA male mice, in acute and repeated exposure. The sub-lethal dose was also administered at two different times and twice at 24-h intervals. Both PHO and DED proved able to induce a dose-dependent increase of micronucleated polychromatic erythrocytes (PCE). The two pesticides also showed a different detoxification time. Furthermore, the CREST staining with antikinetochore antibodies allowed us to conclude that the two chemicals are clastogens.

The 'natural' hybrid haemoglobin from mule. Interrelationships with its parent haemoglobins from horse and donkey.

The equilibrium O2-binding properties of the hybrid haemoglobin (Hb) present in vivo in erythrocytes from mule and of its parent Hbs from horse and donkey were compared with special reference to the effect of heterotropic ligands such as Cl-, D-glycerate 2,3-bisphosphate (DPG) and inositol hexakisphosphate. All these Hbs display a decreased effect by polyphosphates, confirming that what has been observed for horse Hb [Giardina, Brix, Clementi, Scatena, Nicoletti, Cicchetti, Argentin & Condò (1990) Biochem. J. 266, 897-900] is common to other equine species, at least from a qualitative standpoint. However, different quantitative aspects can be detected, which can be accounted for by a different role for the two types of chain in characterizing the binding free energy for the various heterotropic effectors. In particular, it is shown that the binding mode of DPG and inositol hexakisphosphate displays different features since long-range effects can be observed clearly for inositol hexakisphosphate but not for DPG. In general terms, in spite of a different intrinsic O2 affinity, the modulation of functional properties by third ligands leads these Hbs to behave, under physiological conditions, similarly to human HbA. It might represent an interesting example of how different species with similar functional needs find different ways to produce a similar functional behaviour.

Investigations on the PGM (phosphoglucomutase) polymorphism by isoelectric focusing in Drosophila melanogaster.

Pgm allele frequencies of 383 individuals were determined in a sample of Drosophila melanogaster from three laboratory Sardinian populations, using the techniques of standard electrophoresis, heat denaturation, and isoelectric focusing. The analysis of the progeny obtained from informative crosses showed that the isoelectric focusing patterns segregate in a Mendelian way. The Pgm1.00 and Pgm0.70 electrophoretic alleles displayed different isoelectric points, whereas the Pgm1.00,tr and Pgm1.00,ts isoelectrophoretic alleles could not be differentiated when tested by isoelectric focusing. Moreover, the Pgm0.70,ts allele was split into two classes, with isoelectric points of pH 6.4 and pH 6.6.

Differences between horse and human haemoglobins in effects of organic and inorganic anions on oxygen binding.

Despite the fact that the horse is one of the more common domesticated animals, there are few reports dealing with the properties of its blood, and no comprehensive study has been performed on the reactivity of horse haemoglobin towards organic and inorganic ions. Here we report data on the effects of the organic phosphates D-glycerate-2,3-bisphosphate (2,3-DPG) and InsP6, and of chloride on the properties of horse haemoglobin. Thus the effect of saturating concentrations of 2,3-DPG on the oxygen affinity of horse haemoglobin is about 60% lower than with human adult haemoglobin under the same experimental conditions. The same applies also to InsP6, whose effect on oxygen binding to horse haemoglobin is decreased by about 55% compared with human adult haemoglobin. On the whole, horse haemoglobin appears to be much less sensitive to organic phosphates than previously believed. These results are discussed in the light of the primary structure of the molecule.

The segregation distortion (SD) phenomenon in wild populations of Drosophila melanogaster: interaction between chromosomes 3 and SD chromosomes 2.

The Segregation Distortion (SD) phenomenon is a typical case of non-Mendelian segregation in Drosophila melanogaster, due to the dysfunction of sperm bearing a non-SD homologous chromosome. In nature, several factors involved in the expression of the SD phenomenon have been described; among these, a genetic modifier carried by chromosome 3, which enhances the distortion effect of the SD chromosomes. The analysis of natural Sardinian populations, carried out in order to evaluate the presence of chromosome 3 bearing these enhancer factors, has enabled us to ascertain that (a) also in these populations chromosomes 3 with enhancer factors are present, although with frequencies lower than those previously reported in other publications; (b) among these enhancer chromosomes 3, some increase the k of certain chromosomes 2 from values of chromosomes considered non-distorting (k less than or equal to 0.66) to value typical of SD chromosomes. The data obtained also allow us to put forward some considerations regarding the dynamics of the SD phenomenon in Sardinian populations, where the frequency of SD chromosomes is fairly elevated.

Analysis of an SD second chromosome from a natural population of Drosophila melanogaster.

The second chromosome Co-122 (Corato-122) extracted from a natural population of Drosophila melanogaster caught in Corato (Apulia) and maintained in the laboratory over the SM5 balancer chromosome, proved to carry: (1) a Segregation distorter factor, named SdCo; (2) a recessive lethal mutation, termed mle-Co (maleless-Corato), which causes the lethality of only males; (3) another recessive lethal mutation, l(2)Co (lethal (2) Corato), probably arisen in the laboratory by mutation. This mutation accounts for the diminished recovery of homozygous females observed in the stock. The genetic features and the cytological analysis of the SD chromosome are reported, as well as the genetic localization of mle-Co and 1(2)Co and their cytogenetic mapping. An allelism test has ascertained that mle-Co is allelic to mle, a male-specific mutation described by Fukunaga et al., 1975. The tight linkage of mle-Co and l(2)Co with Sd is discussed from the standpoint of population genetics.

Biological parameters and the segregation distortion (SD) phenomenon in Drosophila melanogaster.

The relationship between some biological parameters (mortality, longevity, fertility, fecundity and sex ratio) and segregation of second chromosomes in heterozygous and homozygous SD males has been analyzed. The results obtained in SD/SD+ heterozygous males show: (1) their reduced fertility with respect to that of control males, (2) an alteration in the sex ratio in the SD+ progeny only, and (3) inversely related sex-ratio and segregation distortion values. In SDi/SDj combinations: (1) surprisingly, fertility is intermediate between that of SD/SD+ heterozygous males and that of control males, (2) the segregation ratios of the second chromosomes are normal (0.50), and (3) the sex ratio = 0.50 in both classes of SD progeny. The relationship between mortality (and therefore longevity) and fertility of the different genotypes and fecundity per male indicates that the total productivity of heterozygous males is less than that so far claimed. Indeed, their productivity depends not only on the mechanism of nonformation of the SD+ sperm, but also on their reduced longevity. The k = 0.50 and the high fecundity of SDi/SDj combinations indicated that in these males the SD phenomenon is partially suppressed, the SD chromosomes being insensitive to each other, thus implying that particular Rsp alleles are sensitive to given Sd alleles. The complementation pattern for male fertility of SD homozygous males again supports previous evidence that Sd factors from natural populations are, in effect, different Sd genes.

Cytogenetic Analysis of an SD Chromosome from a Natural Population of DROSOPHILA MELANOGASTER.

The discovery and the cytogenetic characterization of a new SD (Segregation Distorter) chromosome 2 from a natural population in Ranna (Sicily, Italy), SD(Ra), are reported. The main features of this chromosome are as follows: (a) it contains an Sd(Ra) gene with a moderate degree of segregation distortion (k = 0.72), (b) a recessive female sterile gene, fs(2)(TLM), responsible for modifications of the morphology and structure of the tests and ovaries is located at 89.7, (c) SD(Ra)/SD(Ra) males and females are viable but sterile, the females due to homozygosis of fs(2)(TLM) and the males because of homozygosis of a region containing the Sd locus, and (d) SDi/SDj combinations are fertile, thus suggesting that the different Sd factors found in natural populations constitute a multiple allelic series.-These data may indicate that each population containing SD chromosomes has evolved its own genetic architecture for the complex SD system, with specific modifiers and perhaps different Sd genes. The possibility of reconstructing the evolutionary pattern of the SD(Ra) chromosome in the natural Ranna population after the model of Charlesworth and Hartl (1978) and Crow (1979) is considered.

Dynamics of phosphoglucomutase heat sensitivity polymorphism in Culicidae.

In 6 species of mosquitoes of the genera Aedes and Culiseta (Culicidae, Diptera) the frequency of phosphoglucomutase (PGM) heat sensitivity alleles is inversely correlated with the temperature of the environment where larvae develop. These data suggest that different selective values are associated with the PGM thermoresistant and thermosensitive genotypes in the different habitats.

Nonelectrophoretic genetic variability in mosquitoes: polymorphism for temperature-resistant and temperature-sensitive phosphoglucomutase alleles in Culex pipiens.

Homogenates of single individuals of two natural populations and five laboratory populations of Culex pipiens were examined by combining electrophoresis and heat denaturation studies on phosphoglucomutase (PGM). All populations showed a high degree of polymorphism for isoelectrophoretic temperature-resistant (tr) and temperature-sensitive (ts) alleles. Formal genetic data on the heat stability differences of the PGM are given. If both electrophoretic and isoelectrophoretic alleles are taken into account, the mean increase in the degree of heterozygosity is quite remarkable, i.e., about 65%.--The data are considered in relation to the biological significance that this new type of variability of structural genes could have in natural populations.

A simple approach for discovering common nonelectrophoretic enzyme variability: a heat denaturation study in Drosophila melanogaster.

A simple procedure is described to detect genetic heterogeneity within electrophoretic classes at a locus in Drosophila, based on electrophoresis and heat denaturation studies. Temperature-resistant (tr) and temperature-sensitive (ts) isoelectrophoretic alleles at the phosphoglucomutase locus (Pgm) are present at polymorphic frequencies in natural and in laboratory populations of Drosophila melanogaster.