ABSTRACT
Microglia, the brain-resident immune cells, are highly ramified with dynamic processes transiently contacting synapses. These contacts have been reported to be activity-dependent, but this has not been thoroughly studied yet, especially in physiological conditions. Here we investigate neuron-microglia contacts and microglia morphodynamics in mice in an activity-dependent context such as the vigilance states. We report that microglial morphodynamics and microglia-spine contacts are regulated by spontaneous and evoked neuronal activity. We also found that sleep modulates microglial morphodynamics through Cx3cr1 signaling. At the synaptic level, microglial processes are attracted towards active spines during wake, and this relationship is hindered during sleep. Finally, microglial contact increases spine activity, mainly during NREM sleep. Altogether, these results indicate that microglial function at synapses is dependent on neuronal activity and the vigilance states, providing evidence that microglia could be important for synaptic homeostasis and plasticity.
Subject(s)
Microglia , Neurons , Animals , Mice , Microglia/physiology , Neurons/physiology , Synapses/physiology , Signal Transduction/physiology , Sleep , Neuronal Plasticity/physiologyABSTRACT
In recent years, several forensic laboratories have noted an increase in the number of sexual assault cases submitted for testing, often leading to longer turnaround times. In that context, forensic laboratories may be interested in reviewing their procedures to increase productivity. Here, we present two different strategies that were put in place in our laboratory. First, we changed the way sexual assault evidence kits (SAEK) are processed by implementing an optimized workflow that prioritizes the internal samples (vaginal, anal, and oral). This new procedure allowed for a drastic decrease in turnaround time, while maintaining a similar investigative power. Secondly, we used data from casework to target cases and samples that were likely to yield biological material from the perpetrator, in an attempt to avoid dedicating time and effort to cases for which there is a very low probability of obtaining foreign DNA evidence. Among other things, we looked at the likelihood of obtaining DNA from the perpetrator when the complainant reported the use of a condom, has showered after the assault or when the complainant has no memory of the assault. Results show that those circumstances do not dramatically decrease the probability of finding DNA from the perpetrator.
ABSTRACT
The current consensus concerning the prevalence of lytic and lysogenic phage life cycles in aquatic systems is that the host physiological state may influence viral strategies, lysogeny being favoured when hosts have reduced metabolic rates. We explored this hypothesis, by following phage cycle dynamics, host physiological state and metabolic activity over an annual cycle in three lakes subjected to strong seasonal fluctuations, including 4-5 months of ice cover. We observed marked seasonal dynamics of viral and bacterial communities, with low bulk and cell-specific bacterial metabolism in winter, and a dramatic increase in injured bacteria under the ice cover in all lakes. This period was accompanied by contrasting patterns in the proportion of lysogenic cells. In the eutrophic lake, times of low bacterial metabolic rates and high proportion of damaged cells corresponded to highest levels of lysogeny, supporting the notion that hosts are a 'refuge' for viruses. In the two unproductive lakes, peaks of injured cells corresponded to a minimum of lysogeny, suggesting an 'abandon the sinking ship' response, where the prophage replicates before the loss of genome. We suggest that these diverging responses to the host physiological state are not contradictory, but rather that there may be thresholds of cell stress and metabolic activity leading to one or the other response.
Subject(s)
Bacteria/virology , Bacterial Physiological Phenomena , Bacteriophages/physiology , Fresh Water , Seasons , Bacteriophages/pathogenicity , Ecosystem , Fresh Water/microbiology , Fresh Water/virology , Lysogeny/physiology , QuebecSubject(s)
Pancreatic Ducts/pathology , Pancreatitis/etiology , Acute Disease , Adenocarcinoma/secondary , Biopsy/adverse effects , Cholangiopancreatography, Magnetic Resonance , Colonic Neoplasms/pathology , Fatal Outcome , Female , Humans , Liver Neoplasms/secondary , Middle Aged , Pancreatic Pseudocyst/diagnostic imaging , Tomography, X-Ray ComputedABSTRACT
In psychiatric and neurological diseases, sleep is often perturbed. Moreover, recent works on humans and animals tend to show that sleep plays a strong role in memory processes. Reciprocally, sleep dynamics following a learning task is modified [Hubert, Nature (London) 02663, 1 (2004), Peigneux, Neuron 44, 535 (2004)]. However, sleep analysis in humans and animals is often limited to the total sleep and wake duration quantification. These two parameters are not fully able to characterize the sleep dynamics. In mammals sleep presents a complex organization with an alternation of slow wave sleep (SWS) and paradoxical sleep (PS) episodes. Moreover, it has been shown recently that these sleep episodes are frequently interrupted by micro-arousal (without awakening). We present here a detailed analysis of the basal sleep properties emerging from the mechanisms underlying the vigilance states alternation in an animal model. These properties present a self-organized critical system signature and reveal the existence of two W, two SWS, and a PS structure exhibiting a criticality as met in sand piles. We propose a theoretical model of the sleep dynamics based on several interacting neuronal populations. This new model of sleep dynamics presents the same properties as experimentally observed, and explains the variability of the collected data. This experimental and theoretical study suggests that sleep dynamics shares several common features with critical systems.
ABSTRACT
We investigated the dynamics and diversity of heterotrophic bacteria, autotrophic and heterotrophic flagellates, and ciliates from March to July 2002 in the surface waters (0-50 m) of Lake Bourget. The heterotrophic bacteria consisted mainly of "small" cocci, but filaments (>2 microm), commonly considered to be grazing-resistant forms under increased nanoflagellate grazing, were also detected. These elongated cells mainly belonged to the Cytophaga-Flavobacterium (CF) cluster, and were most abundant during spring and early summer, when mixotrophic or heterotrophic flagellates were the main bacterial predators. The CF group strongly dominated fluorescent in situ hybridization-detected cells from March to June, whereas clear changes were observed in early summer when Beta-proteobacteria and Alpha-proteobacteria increased concomitantly with maximal protist grazing pressures. The analysis of protist community structure revealed that the flagellates consisted mainly of cryptomonad forms. The dynamics of Cryptomonas sp. and Dinobryon sp. suggested the potential importance of mixotrophs as consumers of bacteria. This point was verified by an experimental approach based on fluorescent microbeads to assess the potential grazing impact of all protist taxa in the epilimnion. From the results, three distinct periods in the functioning of the epilimnetic microbial loop were identified. In early spring, mixotrophic and heterotrophic flagellates constituted the main bacterivores, and were regulated by the availability of their resources mainly during April (phase 1). Once the "clear water phase" was established, the predation pressure of metazooplankton represented a strong top-down force on all microbial compartments. During this period only mixotrophic flagellates occasionally exerted a significant bacterivory pressure (phase 2). Finally, the early summer was characterized by the highest protozoan grazing impact and by a rapid shift in the carbon pathway transfer, with a fast change-over of the main predators contribution, i.e., mixotrophic, heterotrophic flagellates and ciliates in bacterial mortality. The high abundance of ciliates during this period was consistent with the high densities of resources (heterotrophic nanoflagellates, algae, bacteria) in deep layers containing the most chlorophyll. Bacteria, as ciliates, responded clearly to increasing phytoplankton abundance, and although bacterial grazing impact could vary largely, bacterial abundance seemed to be primarily bottom-up regulated (phase 3).
Subject(s)
Bacteria , Ecosystem , Eukaryota , Fresh Water/microbiology , Fresh Water/parasitology , Animals , Bacteria/classification , Bacteria/isolation & purification , Bacterial Physiological Phenomena , Biodiversity , Biomass , Chlorophyll/analysis , Chlorophyll A , Colony Count, Microbial , Eukaryota/classification , Eukaryota/isolation & purification , Eukaryota/physiology , France , In Situ Hybridization, Fluorescence , PlanktonABSTRACT
We demonstrate the existence of exact discrete compact breather solutions in nonlinear Klein-Gordon systems, and complete the work of Tchofo Dinda and Remoissenet [Phys. Rev. E 60, 6218 (1999)], by showing that the breathers stability is related principally to the lattice boundary conditions, the coupling term, and the harmonicity parameter.
ABSTRACT
We show that by properly choosing the analytical form of a solitary wave solution of discrete phi(4) models we can calculate the parameters of the potential which allow the propagation of compact (kink and pulses) solutions. Our numerical simulations show that narrow kinks and pulses with finite extent can propagate freely, and that discrete breathers with finite but long lifetime, can emerge from their collisions. Moreover, our numerical simulations reveal that the propagation of two successive pulses at a relative distance of two lattice spacings propagate freely, i.e., without interaction.
ABSTRACT
We have explored the dynamics of two versions of a Burridge-Knopoff model: with linear or nonlinear interactions between adjacent blocks. We have shown that by properly choosing the analytical form of the discrete solitary wave solution of the model we can calculate analytically the form of the friction function. In both cases our analytical results show that the friction force naturally presents the behavior of a simple weakening friction law first introduced qualitatively by Burridge and Knopoff [Bull. Seismol. Soc. Am. 57, 3411 (1967)] and quantitatively by Carlson and Langer [Phys. Rev. Lett. 62, 2632 (1989)]. With such a force function the discrete solitonic or compactlike wave-front solutions are exact and stable solutions. In the case of linear coupling our numerical simulations show that an irregular initial state evolves into kink pairs (large-amplitude events), that can recombine or not, plus nonlinear localized modes and small linear oscillations (small-amplitude events) that disperse with time, owing to dispersion. For nonlinear coupling one observes compactlike kink pairs or shocks, and a background of robust incoherent nonlinear oscillations (small amplitude events) that persist with time. Our results show that discreteness is a necessary ingredient to observe a rich and complex dynamical behavior. Nonlinearity allows the existence of strictly localized shocks.
ABSTRACT
Wave front propagation failure is investigated in discrete bistable reaction-diffusion systems. We present a theoretical approach including dissipative effects and leading to an analytical expression of the critical coupling beyond which front propagation can occur as a function of the nonlinearity threshold parameter. Our theoretical predictions are confirmed by numerical simulations and experimental results on an equivalent electrical diffusive lattice.
ABSTRACT
PURPOSE: The aim of the study was to determine the predictive factors of complications, to evaluate the impact of customized treatment planning on late normal tissue effects per stage, and to report disease-free survival (DFS) and local control (LC) rates. METHODS AND MATERIALS: From 1970 to 1994, 642 patients were treated with radiotherapy alone for carcinoma of the intact uterine cervix. According to the International Federation of Gynecology and Obstetrics (FIGO) substaging, 34% were Stage I, 39% Stage II, and 27% Stage III. The analysis was divided into three periods: 1970-1978 (use of standard prescriptions),1979-1984 (implementation of individual adjustments), 1985-1994 (systematic individual adjustments). Five-year DFS, LC, and complications rates were calculated using the Kaplan-Meier method. Predictive factors of complications were determined by univariate analysis using frequency tables and nonparametric t-tests. Multivariate analysis consisted of a polychotomous stepwise regression. RESULTS: The comparison of the three time periods showed a significant reduction of the external radiation dose (dose above 40 Gy in 47% of patients before 1979 vs. 36% after 1984), of the use of parametrial boost (55% vs. 39%), of the use of vaginal cylinder (28% vs. 11.5%), and of the HWT volume (combined intracavitary and external irradiation) (842 cc vs. 503 cc on average). The total sequelae/complications rate, all toxicity grades, all stages, all organs was 51%. Five-year actuarial rate per toxicity grade was: G1, 42%; G2, 23.5%; G3, 10%; G4, 3%. The three main predictive factors for rectal and bladder sequelae/complications (all toxicity grades) taking into account time period were: the increase of external radiation dose, the high dose rate at reference points, and the whole vagina brachytherapy. No G4 occurred in the third period. The rate of G3 complications dropped from 16% to 6% over time: from 5% during the first period to 0% during the third period in Stage I, from 8% to 6% in Stage II, and from 23% to 12% in Stage III. G3 currently describes a variety of clinical situations with a different impact on quality of life which justifies further refinements of definitions of late effects. In our experience the severity of G3 markedly decreased: less than one-third of G3 had a real impact on quality of life in the last period compared to more than two-thirds in the first period. Meanwhile, 5-year LC rates remained stable in Stages I and II, 91% and 85% respectively. Conversely they fell from 75% to 55% in Stage III, thus raising the problem of underdosage and/or more accurate staging with time. CONCLUSIONS: Customized treatment planning eradicated lethal complications and provided a significant decrease of G3 in all stages while maintaining high cure rates in early stages. Dose reduction should be considered with caution in Stage III.
Subject(s)
Radiation Injuries/complications , Uterine Cervical Neoplasms/radiotherapy , Actuarial Analysis , Adult , Aged , Aged, 80 and over , Analysis of Variance , Brachytherapy/methods , Disease-Free Survival , Female , Follow-Up Studies , Humans , Middle Aged , Neoplasm Staging , Prospective Studies , Radiation Injuries/classification , Radiotherapy Dosage , Rectal Diseases/etiology , Severity of Illness Index , Treatment Outcome , Urinary Bladder Diseases/etiology , Uterine Cervical Neoplasms/pathologyABSTRACT
The use of tobacco plants as a novel expression system for the production of human homotrimeric collagen I is presented in this report. Constructs were engineered from cDNA encoding the human proalpha1(I) chain to generate transgenic tobacco plants expressing collagen I. The recombinant proalpha1(I) chains were expressed as disulfide-bonded trimers and were shown to fold into a stable homotrimeric triple helix. Moreover, the recombinant procollagen was subsequently processed to collagen as it occurs in animals. Large amounts of recombinant collagen were purified from field grown plant material. The data suggest that plants are a valuable alternative for the recombinant production of collagen for various medical and scientific purposes.
Subject(s)
Nicotiana/genetics , Plants, Toxic , Procollagen/genetics , Amino Acid Sequence , Circular Dichroism , Electrophoresis, Polyacrylamide Gel , Humans , Microscopy, Electron , Molecular Sequence Data , Plants, Genetically Modified , Procollagen/chemistry , Protein Conformation , Protein Denaturation , Protein Folding , Recombinant Proteins/chemistry , Recombinant Proteins/ultrastructure , TrypsinABSTRACT
We introduce a nonlinear Klein-Gordon lattice model with specific double-well on-site potential, additional constant external force and dissipation terms, which admits exact discrete kink or traveling wave fronts solutions. In the non-dissipative or conservative regime, our numerical simulations show that narrow kinks can propagate freely, and reveal that static or moving discrete breathers, with a finite but long lifetime, can emerge from kink-antikink collisions. In the general dissipative regime, the lifetime of these breathers depends on the importance of the dissipative effects. In the overdamped or diffusive regime, the general equation of motion reduces to a discrete reaction diffusion equation; our simulations show that, for a given potential shape, discrete wave fronts can travel without experiencing any propagation failure but their collisions are inelastic.
Subject(s)
Models, Theoretical , Base Pairing , Biophysical Phenomena , Biophysics , Calcium Signaling , DNA/chemistry , Hydrogen Bonding , Models, Biological , Nonlinear DynamicsABSTRACT
From 1970 to 1994, 642 patients with carcinomas of intact uterine cervix were treated with radiotherapy alone Univariate and multivariate analysis was carried out of predictive factors for: 1) pelvic control and survival rates; 2) complications using French-Italian Syllabus, combined with an evaluation of the impact of customized treatment planning policy (CTP) on G3-G4. According to Figo substaging 30% of patients were stage I, 42% stage II and 28% stage III/IV. Diameter of cervical disease was 3-5 cm in 38% of cases and > 5 cm in 15%. Nodal involvement from lymphangiogram was 21%. The distribution of sequelae and complications was: G1 23%, G2 18%, G3 6%, G4 2.5%. The distribution of G3-G4 per organ was: genitalia 6% (no G4), rectum 4%, colon 1.5%, bladder 1.2%, soft tissues 1%, small bowel 0.5%. Stage (RR ranging from 1.5 for stage IIb to 5 for stage III/IV), tumor size (RR = 1.5), nodal involvement (RR = 2) were significant predictive factors for survival and pelvic control rates (p < 0.0001). In univariate analysis the main factors influencing the risk of G3-G4 complications were: Figo substaging, external radiation dose over 40 Gy (ED), parametrium boost (PB), use of brachytherapy vaginal cylinders applicator (CA), high HWT and mean rectal dose rate for rectal complications. In multivariate analysis, CA remained the only predictive factor for G3-G4 bladder events (odds ratio OR = 10.8) while the increase of mean dose rate (OR = 1.1), use of CA (OR = 4.2) and ED > 40 Gy (OR = 4.4) were predictive of severe rectal sequelae. Prevention of complications based upon individual changes of treatment planning according to dosimetry parameters led to a sharp decrease in severe complications with time. No G4 occurred after 1983. G3 rates dropped from 5% before 1978 to 0% after 1983 in stage I, from 10% to 6% in stage II and from 23% to 12% in stages III/IV. Meanwhile 5-year LC rates remained stable in early stages, about 91% in stage I and 85% in stage II, conversely they fell from 75% to 55% in stages III/IV, thus raising the problem of underdosage and/or more reliable staging with time. It is concluded that radiotherapy prescriptions based upon tumor diameter per stage and delivered using CTP led to an eradication of lethal complications and provided significant decrease of G3 in all cases while maintaining high cure rates in early stages. Dose reduction should be considered with caution in stages III/IV.
Subject(s)
Uterine Cervical Neoplasms/radiotherapy , Brachytherapy , Female , Humans , Neoplasm Staging , Radiation Dosage , Radiation Injuries/classification , Survival Rate , Tissue Survival , Uterine Cervical Neoplasms/mortality , Uterine Cervical Neoplasms/pathologyABSTRACT
A large variety of cells adhere to and spread on specific regions within the triple helix of collagens, mainly via alpha 1 beta 1 and alpha 2 beta 1 integrins. Disruption of collagen triple helical integrity generally affects the efficiency of cell adhesion on different collagens including collagen V. This report addresses the question of the importance of the linear sequence of the constitutive alpha-chains versus the triple helical conformation in the recognition of collagen V binding sites. To investigate this question, in vitro renaturation of the isolated alpha 1 (V) and alpha 2 (V) chains was performed according to the annealing procedure and formation of the triple helix was monitored by rotary shadowing and by mild trypsin digestion followed by electrophoretic analysis. The results indicate that the alpha 1 (V) and alpha 2 (V) homotrimeric reassociation can occur up to a full-length triple helix but intermediate forms of 50-200 nm long rod-like segments are also observed. We have previously shown that alpha 1 beta 1 and alpha 2 beta 1 integrins, the major collagen receptors, are also involved in cell adhesion to native collagen V. Therefore we chose the following two different cell lines for this study: HT1080 (a human fibrosarcoma cell line) expressing alpha 2 beta 1 and HBL100 (a human mammary epithelial cell line) containing significant amounts of alpha 1 beta 1 and alpha 2 beta 1 integrins. We showed that both alpha 1 (V) and alpha 2(V) homotrimers induced cell adhesion but refolded alpha2(V) chains were more efficient and promoted cell adhesion as well as native collagen V. Thermal stability of refolded alpha-chains was monitored by adhesion promoting activity and showed that cell adhesion was dependent on triple helical conformation of the substrates. Adhesion in all cases was strongly Mg2+ and Mn(2+)-dependent and Ca2+ ions alone were ineffective. Antibodies against alpha 2 and beta 1 integrin subunits completely inhibited HT1080 cell adhesion to all substrates. Moreover, addition of cyclic RGD peptides, which had been shown to interact with alpha 2 beta 1, dramatically affected HT1080 cell adhesion to native collagen V and to the refolded alpha-chains. Antibody to beta 1 subunits abolished HBL100 cell adhesion to all substrates. A complete inhibition of HBL100 cell adhesion to native collagen V was achieved only by simultaneous addition of function-blocking specific monoclonal antibodies against alpha 1 and alpha 2 integrin subunits. However, only alpha 2 beta 1 was engaged obviously in HBL100 cell adhesion to refolded alpha-chains. These data indicate that triple helical conformation is particularly critical for alpha 2 beta 1- and alpha 1 beta 1-dependent adhesion and that the integrin alpha 2 beta 1 is a dominant functional receptor for refolded alpha-chains. We conclude that alpha 2 beta 1-dependent adhesion seems to involve multiple different conformational binding sites while alpha 1 beta 1-dependent adhesion is more restricted to the heterotrimeric native form of the molecule.
Subject(s)
Collagen/chemistry , Integrins/chemistry , Animals , Binding Sites , Cell Adhesion , Cell Line , Collagen/physiology , Humans , Integrin alpha1beta1 , Integrins/physiology , Protein Folding , Receptors, CollagenABSTRACT
As there are few recent reports concerning the structure and exact composition of the extracellular matrix from human normal and varicose veins, we carried out comparative immunohistochemical analysis of vessel wall using conventional and confocal laser scanning immunofluorescence techniques. The present report is a rapid review of the structure and function of the 19 known collagen types and our first results on the distribution of collagen types VI, XII and XIV and laminin (glycoprotein from basement membrane) in vein walls. Type VI collagen is concentrated in the sub-endothelium and widely distributed in the media and adventice. For the first time, we demonstrated that both FACIT (fibril-associated) collagens XII and XIV were present in the vein wall, but at different anatomic sites.
Subject(s)
Collagen/analysis , Extracellular Matrix/ultrastructure , Laminin/analysis , Varicose Veins/metabolism , Varicose Veins/pathology , Fluorescent Antibody Technique, Indirect , Humans , Microscopy, Confocal , Saphenous Vein/metabolism , Saphenous Vein/ultrastructureSubject(s)
Adenocarcinoma/radiotherapy , Uterine Cervical Neoplasms/radiotherapy , Adenocarcinoma/mortality , Adenocarcinoma/pathology , Brachytherapy/adverse effects , Brachytherapy/methods , Dose-Response Relationship, Radiation , Female , Follow-Up Studies , Humans , Neoplasm Metastasis , Neoplasm Recurrence, Local , Neoplasm Staging , Radiotherapy Dosage , Survival Rate , Treatment Outcome , Uterine Cervical Neoplasms/mortality , Uterine Cervical Neoplasms/pathologyABSTRACT
Schizosaccharomyces pombe yeast cells grown on either fermentable or respiratory media were efficiently converted to stable spheroplasts by the alpha-(1-->3)-glucanase Novozym 234 in the presence of 1.2 M sorbitol. Lysis of spheroplasts by gentle homogenization in dilute sorbitol resulted in the preparation of mitochondria with a structure similar to that observed within the starting yeast cells. The isolated mitochondria exhibited high oxidation rates with various respiratory substrates, NADH being the most efficient. The mitochondria appeared well coupled since the second State 4 rate observed after ADP consumption was identical to the initial one. The State 3 rate in the presence of ADP was completely inhibited by low oligomycin concentrations, similarly to the concomitant ATP synthesis of 900 nmol/min x mg protein. These NADH oxidation and dependent ATP-synthesis activities are much higher than those previously described for mitochondria isolated from Schizosaccharomyces pombe, and similar to the highest values reported for Saccharomyces cerevisiae.
Subject(s)
Adenosine Triphosphate/biosynthesis , Mitochondria/metabolism , Oxidative Phosphorylation , Schizosaccharomyces/ultrastructure , Adenosine Diphosphate/metabolism , Cell Fractionation/methods , Cell Wall/drug effects , Culture Media , Glycoside Hydrolases/pharmacology , NAD/metabolism , Oxidation-Reduction , Spheroplasts/ultrastructureABSTRACT
To improve our understanding of the beneficial effects of alkylxanthines in various disorders, two animal models were used. The biochemical modifications due to pentoxifylline and HWA 285 on mitochondrial maturation and protein biosynthesis during the neonatal period were determined simultaneously.
Subject(s)
Mitochondria, Liver/drug effects , Pentoxifylline/pharmacology , Protein Biosynthesis , Theobromine/analogs & derivatives , Xanthines/pharmacology , Animals , Animals, Newborn , Glucose/pharmacology , Liver/metabolism , Mitochondria, Liver/metabolism , Oxidative Phosphorylation/drug effects , RatsABSTRACT
The improvement in mitochondrial functions which normally occurs in newborn rat liver in vivo during the few hours following delivery is inhibited by a glucose injection at birth (Meister, R., Comte, J., Baggetto, L., G., Godinot, C. and Gautheron, D.C. (1983) Biochim. Biophys. Acta 722, 36-42). To test whether this improvement could be correlated to changes in cyclic nucleotides, the levels of cAMP and cGMP have been measured during the 2 h following birth. At birth, a short rise followed by a decrease of cAMP occurs, then a significant increase of cAMP level is observed between 45 min and 2 h. The cAMP level for animals injected at birth with glucose is lower than for control animals at each time studied. The cGMP level is not significantly affected in control animals, while in glucose-treated animals a significant decrease of cGMP is observed in the postnatal 2 h. The present work shows also that the glucose-induced inhibition of mitochondrial maturation is mimicked by injection at birth of either 8-Br-cGMP or nitroprusside. The latter transiently increases intracellular cGMP. In contrast, the glucose-induced inhibition is prevented by the injection at birth of either dbcAMP or alkylxanthines together with glucose (Comte, J., Meister, R., Baggetto, L.G., Godinot, C. and Gautheron, D.C. (1986) Biochem. Pharmacol. 35, 2411-2416). It is concluded that the postnatal improvement of mitochondrial functions is stimulated by cAMP and inhibited by cGMP, and that glucose-induced inhibition of the maturation is at least partly supported by a decrease in cAMP but not correlated to an increase in cGMP.