Altered microRNA Transcriptome in Cultured Human Liver Cells upon Infection with Ebola Virus

Ebola virus (EBOV) is a virulent pathogen, notorious for inducing life-threatening hemorrhagic fever, that has been responsible for several outbreaks in Africa and remains a public health threat. Yet, its pathogenesis is still not completely understood. Although there have been numerous studies on host transcriptional response to EBOV, with an emphasis on the clinical features, the impact of EBOV infection on post-transcriptional regulatory elements, such as microRNAs (miRNAs), remains largely unexplored. MiRNAs are involved in inflammation and immunity and are believed to be important modulators of the host response to viral infection. Here, we have used small RNA sequencing (sRNA-Seq), qPCR and functional analyses to obtain the first comparative miRNA transcriptome (miRNome) of a human liver cell line (Huh7) infected with one of the following three EBOV strains: Mayinga (responsible for the first Zaire outbreak in 1976), Makona (responsible for the West Africa outbreak in 2013–2016) and the epizootic Reston (presumably innocuous to humans). Our results highlight specific miRNA-based immunity pathways and substantial differences between the strains beyond their clinical manifestation and pathogenicity. These analyses shed new light into the molecular signature of liver cells upon EBOV infection and reveal new insights into miRNA-based virus attack and host defense strategy.

Platelet Pathogen Reduction Technologies Alter the MicroRNA Profile of Platelet-Derived Microparticles

Despite improvements in donor screening and increasing efforts to avoid contamination and the spread of pathogens in clinical platelet concentrates (PCs), the risks of transfusion-transmitted infections remain important. Relying on an ultraviolet photo activation system, pathogen reduction technologies (PRTs), such as Intercept and Mirasol, utilize amotosalen, and riboflavin (vitamin B2), respectively, to mediate inactivation of pathogen nucleic acids. Although they are expected to increase the safety and prolong the shelf life of clinical PCs, these PRTs might affect the quality and function of platelets, as recently reported. Upon activation, platelets release microparticles (MPs), which are involved in intercellular communications and regulation of gene expression, thereby mediating critical cellular functions. Here, we have used small RNA sequencing (RNA-Seq) to document the effect of PRT treatment on the microRNA profiles of platelets and derived MPs. PRT treatment did not affect the microRNA profile of platelets. However, we observed a specific loading of certain microRNAs into platelet MPs, which was impaired by treatment with Intercept or its Additive solution (SSP+). Whereas, Intercept had an impact on the microRNA profile of platelet-derived MPs, Mirasol did not impact the microRNA profile of platelets and derived MPs, compared to non-treated control. Considering that platelet MPs are able to transfer their microRNA content to recipient cells, and that this content may exert biological activities, those findings suggest that PRT treatment of clinical PCs may modify the bioactivity of the platelets and MPs to be transfused and argue for further investigations into PRT-induced changes in clinical PC content and function.

Complexity of the microRNA transcriptome of cow milk and milk-derived extracellular vesicles isolated via differential ultracentrifugation

MicroRNAs (miRNAs) are small gene-regulatory noncoding RNA that are highly enriched in cow milk. They are encapsulated in different extracellular vesicle (EV) subsets that protect them from the extracellular milieu and the harsh conditions of the gastrointestinal tract during digestion. Here, we isolated pellets enriched in 4 different EV subsets, via differential ultracentrifugation of commercial cow milk: 12,000 × g (P12K), 35,000 × g (P35K), 70,000 × g (P70K), and 100,000 × g (P100K). Small RNA sequencing (sRNA-Seq) analyses revealed an unprecedented level of diversity in the complete miRNA repertoire and features of unfractionated cow milk and derived EV subsets. Although 5 miRNA sequences represented more than 50% of all miRNAs, milk EV exhibited heterogeneous content of miRNAs and isomeric variants (termed isomiR): P100K EV were enriched in reference miRNA sequences, and P12K and P35K EV in related isomiR. Incubation of milk EV with human cultured HeLa cells led to cellular enrichment in miRNA miR-223, which was concomitant with decreased expression of a reporter gene placed under the control of miR-223, thereby demonstrating the functionality of miR-223. These results suggest that cow milk EV may transfer their miRNAs to human cells and regulate recipient cell gene expression programming in a manner as complex as that of their miRNA transcriptome. The biological activity and relevance of the different milk EV subsets and bioactive mediators, including small noncoding RNA, in health and disease, warrants further investigation.

MiR-483-5p and miR-139-5p promote aggressiveness by targeting N-myc downstream-regulated gene family members in adrenocortical cancer

Adrenocortical carcinoma (ACC) is a tumor with poor prognosis in which overexpression of a panel of microRNAs has been associated with malignancy but a very limited number of investigations on their role in ACC pathogenesis have been conducted. We examined the involvement of miR-483-5p and miR-139-5p in adrenocortical cancer aggressiveness. Using bioinformatics predictions and mRNA/miRNA expression profiles, we performed an integrated analysis to identify inversely correlated miRNA-mRNA pairs in ACC. We identified N-myc downstream-regulated gene family members 2 and 4 (NDRG2 and NDRG4) as targets of miR-483-5p and miR-139-5p, respectively. NDRG2 and NDRG4 expressions were inversely correlated respectively with miR-483-5p and miR-139-5p levels in aggressive ACC samples from two independent cohorts of 20 and 44 ACC. Moreover, upregulation of miR-139-5p and downregulation of NDRG4 demonstrated a striking prognostic value. A direct interaction between miR-483-5p or miR-139-5p and their targets was demonstrated in reporter assays. Downregulation of miR-483-5p or miR-139-5p in the ACC cell lines NCI-H295R and SW13 increased NDRG2 or NDRG4 mRNA and protein expression, compromised adrenocortical cancer cell invasiveness and anchorage-independent growth. MiR-483-5p or miR-139-5p overexpression and NDRG2 or NDRG4 inhibition produce similar changes, which are rescued by NDRG2 or NDRG4 ectopic expression. We established that key factors mediating epithelial-to-mesenchymal transition are downstream effectors of miR-483-5p/NDRG2 and miR-139-5p/NDRG4 pathways. Collectively, our data show for the first time that miR-483-5p/NDRG2 and miR-139-5p/NDRG4 axes promote ACC aggressiveness, with potential implications for prognosis and therapeutic interventions in adrenocortical malignancies.

A subset of extracellular vesicles carries the bulk of microRNAs in commercial dairy cow's milk

MicroRNAs are small gene-regulatory RNAs that are found in various biological fluids, including milk, where they are often contained inside extracellular vesicles (EVs), like exosomes. In a previous study, we reported that commercial dairy cow's milk microRNAs resisted simulated digestion and were not exclusively associated with canonical exosomes. Here, we report the characterization of a milk EV subset that sediments at lower ultracentrifugation speeds and that contains the bulk of microRNAs. Milk EVs were isolated by differential ultracentrifugation and Iodixanol density gradient (IDG), and analysed for (1) microRNA enrichment by reverse transcription and quantitative polymerase chain reaction (RT-qPCR), and (2) EV-associated proteins by Western blot. Milk EVs were characterized further by dynamic light scattering (DLS), density measurements, fluorescent DiR and RNA labelling, high-sensitivity flow cytometry (HS-FCM), transmission electron microscopy (TEM), proteinase K and RNase A assay, and liquid chromatography tandem-mass spectrometry (LC-MS/MS). We found that the bulk of milk microRNAs (e.g., bta-miR-125b, bta-miR-148a, etc.) sediment at 12,000 g and 35,000 g. Their distribution pattern was different from that of exosome-enriched proteins, but similar to that of several proteins commonly found in milk fat globule membranes (MFGM), including xanthine dehydrogenase (XDH). These low-speed ultracentrifugation pellets contained cytoplasm-enclosing phospholipid bilayered membrane vesicles of a density comprised between 1.11 and 1.14 g/mL in Iodixanol. This milk EV subset of ~100 nm in diameter/~200 nm hydrodynamic size resisted to proteinase K digestion and protected their microRNA content from RNase A digestion. Our results support the existence of a milk EV subset pelleting at low ultracentrifugations speeds, with a protein coating comparable with MFGM, which contains and protects the bulk of milk microRNAs from degradation. This milk EV subset may represent a new EV population of interest, whose content in microRNAs and proteins supports its potential bioactivity.

Pathogen reduction technologies: The pros and cons for platelet transfusion

The transfusion of platelets is essential for diverse pathological conditions associated with thrombocytopenia or platelet disorders. To maintain optimal platelet quality and functions, platelets are stored as platelet concentrates (PCs) at room temperature under continuous agitation-conditions that are permissive for microbial proliferation. In order to reduce these contaminants, pathogen reduction technologies (PRTs) were developed by the pharmaceutical industry and subsequently implemented by blood banks. PRTs rely on chemically induced cross-linking and inactivation of nucleic acids. These technologies were initially introduced for the treatment of plasma and, more recently, for PCs given the absence of a nucleus in platelets. Several studies verified the effectiveness of PRTs to inactivate a broad array of bacteria, viruses, and parasites. However, the safety of PRT-treated platelets has been questioned in other studies, which focused on the impact of PRTs on platelet quality and functions. In this article, we review the literature regarding PRTs, and present the advantages and disadvantages related to their application in platelet transfusion medicine.

Commercial Dairy Cow Milk microRNAs Resist Digestion under Simulated Gastrointestinal Tract Conditions

BACKGROUND

MicroRNAs are small, gene-regulatory noncoding RNA species present in large amounts in milk, where they seem to be protected against degradative conditions, presumably because of their association with exosomes.

OBJECTIVE

We monitored the relative stability of commercial dairy cow milk microRNAs during digestion and examined their associations with extracellular vesicles (EVs).

METHODS

We used a computer-controlled, in vitro, gastrointestinal model TNO intestinal model-1 (TIM-1) and analyzed, by quantitative polymerase chain reaction, the concentration of 2 microRNAs within gastrointestinal tract compartments at different points in time. EVs within TIM-1 digested and nondigested samples were studied by immunoblotting, dynamic light scattering, quantitative polymerase chain reaction, and density measurements.

RESULTS

A large quantity of dairy milk Bos taurus microRNA-223 (bta-miR-223) and bta-miR-125b (∼10⁹-10¹⁰ copies/300 mL milk) withstood digestion under simulated gastrointestinal tract conditions, with the stomach causing the most important decrease in microRNA amounts. A large quantity of these 2 microRNAs (∼10⁸-10⁹ copies/300 mL milk) was detected in the upper small intestine compartments, which supports their potential bioaccessibility. A protocol optimized for the enrichment of dairy milk exosomes yielded a 100,000 × g pellet fraction that was positive for the exosomal markers tumor susceptibility gene-101 (TSG101), apoptosis-linked gene 2-interacting protein X (ALIX), and heat shock protein 70 (HSP70) and containing bta-miR-223 and bta-miR-125b. This approach, based on successive ultracentrifugation steps, also revealed the existence of ALIX^-, HSP70^-/low, and TSG101^-/low EVs larger than exosomes and 2-6 times more enriched in bta-miR-223 and bta-miR-125b (P < 0.05).

CONCLUSIONS

Our findings indicate that commercial dairy cow milk contains numerous microRNAs that can resist digestion and are associated mostly with ALIX^-, HSP70^-/low, and TSG101^-/low EVs. Our results support the existence of interspecies transfer of microRNAs mediated by milk consumption and challenge our current view of exosomes as the sole carriers of milk-derived microRNAs.

Prevention of Candida colonization prevents infection in a neonatal unit

This study represents a 1-year surveillance period using our epidemiology-based principles published and successfully followed since 1979: weekly culture for yeasts of oral and anal swabs, treatment with oral nystatin of all colonized newborns, and good hygiene/handwashing. Colonization was demonstrated in 23 out of 791 newborns admitted from October 1998 to September 1999. Twenty-two strains of Candida were identified: 16 C. albicans, 2 C. parapsilosis, 3 C. glabrata, and 1 C. tropicalis. Symptoms were erythema of the buttocks in 6 colonized newborns. No other culture positive for Candida could be found. Previous contamination was the main source (previous stay in an intensive care unit, rarely maternal origin). Contamination in the unit was unlikely. Eradication of Candida could be observed within 1 week. These good results, controversial in the literature, were obtained following epidemiological conclusions and support our guidelines.

Spread of Stenotrophomonas maltophilia colonization in a pediatric intensive care unit detected by monitoring tracheal bacterial carriage and molecular typing

In our pediatric intensive care unit in Tours (France), intubated and ventilated inpatients are systematically monitored for tracheal bacterial colonization twice a week. This led us to detect five patients colonized with Stenotrophomonas maltophilia over a 4-month period. Molecular typing of the isolates using random amplified polymorphism DNA (RAPD) and pulsed-field gel electrophoresis (PFGE) confirmed that four of the five isolates were genetically related. The strict isolation of carriers and improvements in hygiene measures stopped the spread. This systematic strategy prevented pulmonary nosocomial infections or allowed their early detection. Moreover, it has made it possible to assess the efficiency of care practices continuously.

Comparison of Fecal Flora following Administration of Two Antibiotic Protocols for Suspected Maternofetal Infection

Two protocols are used by French neonatologists for the treatment of suspected maternofetal infection (SMFI). Three groups of premature and term neonates were included to study the impact of antibiotics on fecal flora: 10 infants with SMFI treated with amoxicillin and netilmicin (group BI), 10 infants with SMFI treated with amoxicillin, cefotoxime and netilmicin (group TRI) and 10 infants without antibiotic therapy as controls (group C). Group BI samples were colonized with Klebsiella oxytoca and Escherichia coli resistant to amoxicillin and by Eneterococcus faecium and coagulase-negative staphylococci. In group TRI biodiversity of the intestinal flora was low, with rapid growth of staphyloccoci and occurrence of Candida spp. These modifications of the intestinal flora should encourage us to use antibiotic treatment as targeted as possible.

Étude de la corrélation entre les prescriptions d’antibiotiques et les recommandations dans une unité de soins intensifs néonatals

The increasing use of wide spectrum antibiotics has been reported to be associated with a greater prevalence of multi-resistant bacteria.

OBJECTIVES

The aims of this study were to survey the use of antibiotics and to evaluate the correlations between patterns of prescription of antibiotics and prescription guidelines in a neonatal intensive care unit.

MATERIAL AND METHODS

In this 6-month study, all newborns admitted to the NICU and treated with antibiotics were included. Data regarding criteria of antibiotic prescription, length of treatment, and criteria of withdrawing treatment were collected. The correlation between prescriptions and guidelines was evaluated a posteriori by a non-prescriber physician. One hundred and sixteen newborns were included, of whom nine had received antibiotics on more than one occasion. Mean gestational age was 33.5 weeks. In 82% of cases, the reason for hospitalisation was respiratory distress syndrome.

RESULTS

Patients received systemic antibiotics for primary infection (78%), nosocomial infection (17%) and postsurgical prophylaxis (5%). Suspected foeto-maternal infections (SFMI) were the dominant features of primary infection (96%). In 49% of cases, suspected infection was not proven and justified withdrawal of treatment within 3 days. Sixty percent of nosocomial infections occurred in newborns with gestational ages of less than 28 weeks. Bacterial criteria were decision-making factors only in nosocomial infections. An absence of observance of guidelines occurred in 9% of treated newborns, and in most cases involved excessive length of treatment.

CONCLUSION

These results show: (1) the majority of antibiotic prescriptions were for not proven SMFI; (2) a low rate of nosocomial infections; (3) the predominance of nosocomial infections in premature newborns; (4) less than 10% of non-observance of guidelines. It appears necessary to develop more precise guidelines to limit antibiotic use and to evaluate them regularly.

[Staphylococcal pneumonia in a premature neonate: unusual transmission of nosocomial infection]

Late onset of neonatal infection could have been transmitted in prenatal period, but it is usually secondary to a postnatal transmission.

CASE REPORT

A premature neonate developed staphylococcal pneumonia at 18 days of life. Genomic typing of the strains of Staphylococcus aureus obtained from the patient and from his mother (found in the endocervix culture 48 h before delivery) was identical. These strains were different from those isolated in other neonates colonised by S. aureus in the unit during at that moment.

CONCLUSION

The observed case of staphylococcal pneumonia may correspond to a nosocomial infection secondary to a pre- or postnatal transmission of the agent by the mother.

[Medical, cognitive and affective status of four-year-old very premature babies without severe disability. A case-control study]

AIM

To determine cognitive performances and affective development of a cohort of very premature babies at the age of 4 years.

POPULATION AND METHODS

Longitudinal case-control study. Newborns less than 33 weeks gestation were included from 1992 to 1994 and were matched with two full-term newborns. At 4 years of age, they have been evaluated for medical status, cognitive functions with the K-ABC test and affective condition with the PSA and Conners' tests.

RESULTS

The preterm group was significantly different from the controls for: a smaller height, (P < 0.01), a lower socioeconomic level (P = 0.027), a lower nursery school level (44% versus 27,6%, P = 0.05), the incapacity to draw "a bonhomme" (55,3% versus 93%, P < 0.001), lower performances for the K-ABC and PSA tests, a pathologic Conners score (20.4% versus 2.4%, P < 0.001). Multivariate analysis by logistic regression showed a similar neuropsychological results: a lower score of K-ABC (< 80, P = 0.0006, odds-ratio = 33.2), and a lower social competence score of PSA (< 45, P = 0.004, odds-ratio = 35.9).

CONCLUSION

Follow-up of premature babies is required, and measures to prevent or minimize cognitive and social disabilities are mandatory.

[Necrotizing enterocolitis and apnoeas-bradycardias of the preterm newborn]

We conducted a case control study during six and a half years with the objective to analyse the risk factors for NEC.

POPULATION AND METHODS

All cases of confirmed NEC matched to controls for identical gestational age and period of hospitalization; apnoeas-bradycardias prospectively counted.

RESULTS

Forty-five cases were compared to 89 controls. The isolated risk factors were: an intra-uterine growth retardation (OR = 3,65, 95% confidence interval [CI] 95%: 1,54-8,63); a birth weight < 1000 g (OR = 8,16, CI 95%: 1,17-56,62), compared to a weight >/= 1500 g; a triple antibiotherapy (OR = 6,15, CI 95%: 1,16-32,45); an umbilical venous catheterization (OR = 2,64, CI 95%: 1,09-6,44); a number of simple apnoeas-bradycardias >/= 3rd tercile (n = 27) (OR = 4,54, CI 95%: 1,29-15,93), or severe (stimulated or with hypoxia) apnoeas-bradycardias >/= 3rd tercile (n = 8) (OR = 6,15, CI 95%: 1,59-23,75); an haemoglobin level lower than the 1(st) tercile (95 g/L) (OR = 5,90, CI 95%: 1,20-20,13); and milk thickening by Gumilk (OR = 2,78, CI 95%: 1,11-6,90).

CONCLUSION

In the present practices, anoxo-ischemic factors during the first week of life do not represent an important risk of NEC; a great vigilance must be exercised for indications of the triple antibiotherapy and the treatment of apnoeas-bradycardias.

Incidence of Reye's syndrome in France: a hospital-based survey

At the time of the study no information was available in France about the incidence of Reye's Syndrome (RS) and no warnings about RS and aspirin. The objective was to evaluate the incidence of RS in France by a hospital-based study. For a period of 1 year from November 1995 to November 1996, all French paediatric departments were required to report any child under 15 years with unexplained noninflammatory encephalopathy (i.e., CDC consciousness level stage I or deeper with normal CSF) and a threefold (or greater) increase in serum aminotransferase and/or ammonia. All suspected cases were classified by a panel of experts as probable RS or excluded RS. In 10% of randomly selected paediatric departments we checked that every suspected case had been reported. Forty-six suspected cases were reported during the year of the survey, of which 14 were classified as RS. Five of these 14 cases had a metabolic disorder. Nine children were definitively diagnosed as having RS (i.e., an estimated incidence of RS of 0.79/1,000,000 children, i.e., below 15/year). Eight children had been exposed to aspirin, four to aspirin alone and four to aspirin and acetaminophen. On the basis of these results the incidence of RS in France in 1996-1997 was not substantially different from that of countries where warning labels were already in use, but it was higher than in the US after 1994. This was probably due to the reduction in aspirin prescription in France because of warnings in Europe and the US and also because many cases of RS are now identified as metabolic disease. On the basis of these results and because the relationship between aspirin and RS has already been proved, public and professional warnings concerning RS on aspirin-containing products in cases of varicella and viral febrile illness have been adopted by the French Drugs Agency.

mRNA D(2) dopaminergic receptor expression after hypoxia-ischemia in rat immature brain

Previous studies have shown a reduction of dopaminergic D(2) receptors (D(2)R) in the striatum after hypoxia-ischemia in newborn rats. We show here an early and transient reduction of mRNA D(2)R in nonatrophic brains following hypoxia-ischemia. The left carotid artery of P7 rats was ligated followed by hypoxia for 2 h. The rats were sacrificed after 24 h, 48 h and 14 days. D(2)R mRNA was studied by in situ hybridization, the cell number by conventional histology, and neuronal and astrocyte differentiation by immunohistochemistry. A 20% reduction of striatal mRNA D(2)R occurred 24 h after hypoxia-ischemia, whereas no reduction was observed after 48 h and 14 days. There were no differences in total cell number and in the expression of neuronal (MAP-1, MAP-2) and astrocyte (GFAP) markers between both brain hemispheres nor between control and hypoxia-ischemia animals. The early decrease in mRNA D(2)R could explain the delayed reduced D(2)R after neonatal hypoxia-ischemia.

Novel square planar copper(II) complexes with imino or nitronyl nitroxide radicals exhibiting large ferro- and antiferromagnetic interactions

This paper reports the synthesis, crystal structures, and magnetic properties of two copper(II) complexes (1, 2) of general formula Cu(tfac)2(radical)2 (tfac = trifluoroacetate; radical = (1) 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (NITPh) or (2) 2-phenyl-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazoline-1- oxyl (IMPh)). They crystallize in the monoclinic P2(1)/n space group with the following parameters: (1) a = 13.212(2) A, b = 9.136(1) A, c = 15.587(2) A, beta = 114.61(1) degrees, Z = 2; (2) a = 11.059(2) A, b = 15.289(1) A, c = 10.694(2) A, beta = 114.20(1) degrees, Z = 2. In both complexes the copper(II) ion is coordinated to two radicals in a slightly distorted square planar surrounding. The copper(II)-radical exchange couplings are antiferromagnetic for the nitronyl nitroxide (NITPh) complex (1) and ferromagnetic in the case of the imino nitroxide (IMPh) analogue (2). The ground state has been found to be a spin-doublet for 1 and the spin-quartet for 2. No thermal population of the highest states has been observed, indicating copper(II)-radical couplings of magnitude of J > 500 cm-1.

[Medical and psychological status of one-year-old premature babies without severe disability. Case-control prospective study]

BACKGROUND

This case-control prospective study was conducted to determine whether and how medical, psychological and affective development differs from premature to full-term newborns without severe disability.

POPULATION AND METHODS

Newborns under or at 33 weeks gestation (W) were included from December 1992 to January 1994 and were matched with two controls. The same examiners evaluated each infant at the effective postnatal age of nine to ten months.

RESULTS

Fifty premature babies (average gestational age [GA] = 30.7 W) were compared to 100 controls. The main problems were bronchopulmonary (P = 0.03) and sleep (P = 0.027) disorders. Motor disability was suspected in 9% of the cases and none control (P = 0.00003, OR = 3.44). By multivariate analysis, cases differed from the controls by infant-mother relation disturbances (OR = 13.3), motherhood anxiety (OR = 13.3), poor expressiveness (OR = 5.6), peripheral tonus anomalies (OR = 39.5) and sleep troubles (OR = 5.8).

CONCLUSION

Premature newborns had risks for the child-mother relation but not for psychoaffective development disturbances.

Consequences of pulmonary inflations (sighs) on cerebral haemodynamics in neonates ventilated by high-frequency oscillation

High-frequency oscillation (HFO) is a technique frequently used in neonatal resuscitation, but which has yet to be evaluated. The use of intrathoracic pressures may have an effect on the cerebral circulation of immature neonates. The aim of this study was to examine the variations in cerebral blood velocity and oxygenation during brief pulmonary inflations (sighs), by focusing on alveolar recruitment. In this prospective study performed in 13 intubated and ventilated neonates (alpha = 5%; 1-beta = 80%), mean blood velocity and Doppler Resistance Index were measured, and variations in chromophores concentrations were evaluated by near infrared spectroscopy. Brief inflations at 4 cm H2O above the mean regulated intra-thoracic pressure did not cause any variation in the parameters measured. An explanation for this discordance with animal studies may be the level of pressure chosen, which could be more appropriate for the pulmonary compliance of neonates.

Congenital neonatal myotonic dystrophy with persistent pulmonary hypertension and coma: a difficult diagnosis

The fulminant forms of congenital myotonic dystrophy, which rapidly lead to death, are difficult to diagnose. The case described illustrates the roles of persistent pulmonary hypertension in such a fatal form.

[Emergency electroencephalography during perinatal cerebral intensive care: indications and results]

The main contribution of EEG during intensive care in infants with hypoxic-ischemic encephalopathy is i) to help determine whether infants with subtle clinical manifestations present with epileptic seizures, ii) to determine whether paralyzed or heavily sedated infants present with convulsive phenomena, iii) to assess the therapeutical response to anticonvulsants, 4) to contribute, in combination with ultrasound scanning, to diagnostic evaluation of the severity of lesions, and to provide valuable prognostic informations via the analysis of the background activity, as normal EEG is highly predictive of normal outcome, whereas various abnormal EEG features are constantly associated with subsequent major neurological abnormalities or death. These EEG features are readily available from a very early stage and may both precede and be prognostically more sensitive than information obtained from ultrasound. Recording of neonatal electroencephalogram requires awareness of the normal development of electroencephalographic features in the newborn, skilled technicians, and experienced readers of EEG tracings.

[Circulation and cerebral metabolism in neonatal hypoxia-ischemia]

The basic physiological variable in hypoxic-ischaemic brain injury is cerebral oxygen delivery. When oxygen delivery becomes insufficient to meet the cellular demands for oxygen, a sequence of biochemical events will be triggered leading to cell death. High levels of CBF following severe birth asphyxia is now well documented by Doppler ultrasound which has been shown to be a useful prognostic indicator following birth asphyxia. Near infrared spectroscopy (NIRS) is of great potential value since it may be used at the bed-sid and allows to measure the cerebral blood volume and the concentrations of cytochrome aa3. Magnetic resonance spectroscopy (MRS) allows noninvasive assessment of cerebral metabolism in asphyxiated neonates. 31P MRS has demonstrated that birth asphyxia leads to delayed impairment of cerebral energy metabolism and is predictive of later neurodevelopmental outcome. 1H MRS has shown lactate accumulation and a later decline in N-acetyl aspartate concentration.

In vivo sensitivity of murine haemopoietic progenitor cell populations to mixed gamma-rays - neutron irradiation at different gamma/n ratios

Changes in mice haemopoietic cellular populations and in the radiosensitivity of CFU-C and BFUe progenitors cells were determined in vivo for mixed field radiations composed of a gamma-ray component and a neutron component. Five Dgamma/Dtotal ratios (gamma-rays over total dose ratios, quoted as tau in this report) were obtained (tau = 0.95, 0.83, 0.67, 0.33 and 0.09). Myelogram changes were enlarged with the increase of the neutron component. Radiosensitivity of the two progenitor cell lineages were increased with lower tau values (excess of neutrons). The radiosensitivity of haemopoietic progenitor cells exposed in vivo varies with the ratio of the high- and low-LET components in the mixture. The D0 value varied from 3.3 +/- 0.22 to 0.85 +/- 0.04 Gy with the decrease of tau for CFU-C and from 2.08 +/- 0.22 to 0.64 +/- 0.07 Gy for BFUe. The obtained relative biologic efficiency (RBE) varied from 1.2 +/- 0.08 to 4.7 +/- 0.24 for CFU-C and from 1.1 +/- 0.1 to 3.6 +/- 0.16 for the BFUe. The relation between RBE and tau could be somewhat non-linear for CFU-C and seems to be close to linear for BFUe. The higher is the neutron component, the higher is the radiosensitivity. These results indicate that variations of the quality of the mixed field in the haemopoietic local territory are of great importance in terms of radiation damage and cell killing as well as in terms of the ability to restore the haemopoietic system.