The significance of computer-assisted surgery in avoiding double-barrel fibula grafts in reconstruction of the horizontal mandibular ramus.

It is recognized that the mandibular reconstruction with free flap allows for both functional and aesthetic restoration. The flap must be used for reconstruction of a smooth lower mandibular contour and also the alveolar bone to allow dental rehabilitation. The double-barrel fibula free flap does respond well to these imperatives, but it increases risk of vascular complications. To overcome these risks, we propose a single-barrel fibula free flap, positioned at the alveolar level and a customized 3D implant, designed by computer-assisted surgery, at the basilar level. The interest of the single-barrel fibula associated with a customized 3D implant compared to the double-barrel fibula free flap is twofold: it decreases the vascular risks associated with the plication of the second pedicle and allows patients to have a pedicle of greater length. It also allows them to have a good cortical bone placed in the alveolar bone to rehabilitate the mastication function.

Differences in prefrontal cortex GABA/glutamate ratio after acute restraint stress in rats are associated with specific behavioral and neurobiological patterns.

In patients suffering from stress-related pathologies and depression, frontal cortex GABA and glutamate contents are reported to decrease and increase, respectively. This suggests that the GABA and/or glutamate content may participate in pathological phenotype expression. Whether differences in frontal cortex GABA and glutamate contents would be associated with specific behavioral and neurobiological patterns remains unclear, especially in the event of exposure to moderate stress. We hypothesized that an increase in prefrontal cortex GABA/glutamate ratio would be associated with a blunted prefrontal cortex activation, an enhanced hypothalamo-pituitary-adrenocortical (HPA) axis activation and changes in behavior. Rats being restrained for 1-h were then tested in an open-field test in order to assess their behavior while under stress, and were sacrificed immediately afterward. The GABA/glutamate ratio was assessed by (1)H high-resolution magic angle spinning magnetic resonance spectroscopy ((1)H-HRMAS-MRS). The neurobiological response was evaluated through prefrontal cortex mRNA expression and plasma corticosterone levels. The stressed rats were distributed into two subgroups according to their high (H-G/g) or low (L-G/g) GABA/glutamate ratio. Compared to the L-G/g rats, the H-G/g rats exhibited a decrease in c-fos, Arc, Npas4, Nr4a2 mRNA expression suggesting blunted prefrontal cortex activation. They also showed a more pronounced stress with an enhanced rise in corticosterone, alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), creatine kinase (CK) and lactate dehydrogenase (LDH) levels, as well as behavioral disturbances with decreased locomotion speed. These changes were independent from prefrontal cortex energetic status as mammalian target of rapamycin (mTOR) and adenosine monophosphate-activated protein kinase (AMPK) pathway activities were similar in both subpopulations. The differences in GABA/glutamate ratio in the frontal cortex observed in the stressed animals may participate in shaping individual differences in psychophysiological reactions.

NitroScape: a model to integrate nitrogen transfers and transformations in rural landscapes.

Modelling nitrogen transfer and transformation at the landscape scale is relevant to estimate the mobility of the reactive forms of nitrogen (N(r)) and the associated threats to the environment. Here we describe the development of a spatially and temporally explicit model to integrate N(r) transfer and transformation at the landscape scale. The model couples four existing models, to simulate atmospheric, farm, agro-ecosystem and hydrological N(r) fluxes and transformations within a landscape. Simulations were carried out on a theoretical landscape consisting of pig-crop farms interspersed with unmanaged ecosystems. Simulation results illustrated the effect of spatial interactions between landscape elements on N(r) fluxes and losses to the environment. More than 10% of the total N(2)O emissions were due to indirect emissions. The nitrogen budgets and transformations of the unmanaged ecosystems varied considerably, depending on their location within the landscape. The model represents a new tool for assessing the effect of changes in landscape structure on N(r) fluxes.

Effects of farm heterogeneity and methods for upscaling on modelled nitrogen losses in agricultural landscapes.

The aim of this study is to illustrate the importance of farm scale heterogeneity on nitrogen (N) losses in agricultural landscapes. Results are exemplified with a chain of N models calculating farm-N balances and distributing the N-surplus to N-losses (volatilisation, denitrification, leaching) and soil-N accumulation/release in a Danish landscape. Possible non-linearities in upscaling are assessed by comparing average model results based on (i) individual farm level calculations and (ii) averaged inputs at landscape level. Effects of the non-linearities that appear when scaling up from farm to landscape are demonstrated. Especially in relation to ammonia losses the non-linearity between livestock density and N-loss is significant (p > 0.999), with around 20-30% difference compared to a scaling procedure not taking this non-linearity into account. A significant effect of farm type on soil N accumulation (p > 0.95) was also identified and needs to be included when modelling landscape level N-fluxes and greenhouse gas emissions.

Sensitivity analysis for models of greenhouse gas emissions at farm level. Case study of N(2)O emissions simulated by the CERES-EGC model.

Modelling complex systems such as farms often requires quantification of a large number of input factors. Sensitivity analyses are useful to reduce the number of input factors that are required to be measured or estimated accurately. Three methods of sensitivity analysis (the Morris method, the rank regression and correlation method and the Extended Fourier Amplitude Sensitivity Test method) were compared in the case of the CERES-EGC model applied to crops of a dairy farm. The qualitative Morris method provided a screening of the input factors. The two other quantitative methods were used to investigate more thoroughly the effects of input factors on output variables. Despite differences in terms of concepts and assumptions, the three methods provided similar results. Among the 44 factors under study, N(2)O emissions were mainly sensitive to the fraction of N(2)O emitted during denitrification, the maximum rate of nitrification, the soil bulk density and the cropland area.

Effect of 3D nitrogen, dry mass per area and local irradiance on canopy photosynthesis within leaves of contrasted heterogeneous maize crops.

BACKGROUND AND AIMS: Nitrogen partitioning within stands has been described fairly comprehensively, especially for C(3) plants in dense stands where the horizontal heterogeneity of foliage distribution is relatively small. Nitrogen has been shown to be distributed vertically and in parallel to light, maximizing carbon assimilation and stand productivity. Conversely, row crops such as maize (C(4) plants) are characterized by strong horizontal heterogeneity of foliage distribution, and a three-dimensional (3D) approach is required to investigate the combined effect of spatial distribution of nitrogen and light on canopy photosynthesis. MODEL: The 3D geometry of maize canopies was modelled with varying densities and at different developmental stages using plant digitizing under field conditions. For lamina parts, photosynthesis was measured and nitrogen content per unit area (N(a)) was described from analysis of nitrogen content per unit mass (N(m)) and dry mass per unit area (M(a)). Hyperbolic relationships between photosynthesis at irradiance saturation (P(max)) and N(a) were established as well as a linear relationship between dark respiration (R(d)) and N(a), whereas quantum efficiency (alpha) was found to be independent of N(a). KEY RESULTS AND CONCLUSIONS: N(m), M(a) and N(a) were shown to change over time vertically (i.e. between laminae), which has been largely reported previously, and horizontally (i.e. within laminae), which has scarcely been described previously. Even if M(a) played a major role in N(a), a strong relationship between N(a) and M(a) could not be demonstrated, whereas several previous studies have found that N(a) was essentially related to M(a) rather than N(m). From simulations of radiative exchange using a 3D volume-based approach and lamina photosynthesis using a hyperbola, it was shown that real patterns of N(a) partitioning could increase daily crop photosynthesis by up to 8 % compared with uniform patterns of N(a), especially for the earliest stages of stand development.

A novel supraclavicular approach to brachial plexus block.

We describe a novel supraclavicular approach to the brachial plexus. Designated as the intersternocleidomastoid technique, this new approach was tested in unembalmed cadavers. It was then applied for evaluation to 150 ASA grade I or II patients scheduled for elective surgery or physiotherapy of the upper limb or for treatment of reflex sympathetic dystrophy associated with painful shoulder. The new approach was easy to master because of a very simple surface landmark, i.e., the triangle formed by the sternocleidomastoid heads, which were visible and palpable in most patients studied (90%). The procedure was effective intraoperatively, providing satisfactory anesthesia in 140 patients (93%), partially satisfactory blocks in 6 (4%), and unsatisfactory blocks in only 4 (3%). The catheter entry point is cephalad enough not to obscure the surgical field on the shoulder. Catheter insertion was successful in 63 of 70 patients. Postoperative analgesia was provided for 48 h or more in 45 patients and for 24 h in 18 patients. Only minor complications were observed: asymptomatic phrenic nerve block in 89 patients (60%), transient Horner's syndrome in 15 (10%), transient recurrent laryngeal nerve blockade in 2, and misplacement of the catheter into the subclavian vein in 1 patient. No pneumothorax was observed.

Oxygen-induced modifications of benzodiazepine receptors and D2 dopamine receptors in the rat under hyperoxia.

Peripheral-type benzodiazepine Receptors (PBR) in the kidney and Central-type Benzodiazepine Receptors (CBR) in the cerebral cortex were not affected in rats exposed to chronic hyperoxia (85% O2, ATA, 6 days). Nevertheless, cortical CBR showed a significant decrease (29%) after hyperbaric hyperoxia (100% O2, 3.5 ATA, 2 h) in rats at a preconvulsive stage, with no concomitant alteration of kidney PBR. A similar down-regulation of striatal D2 dopamine receptors was noticed (27%)--after hyperbaric hyperoxia--without any modification of cortical PBR. On the contrary, an up regulation of liver PBR was obtained in the same conditions (20%). It is likely that receptors implicated in neurotransmission are particularly down regulated or altered under hyperbaric hyperoxia.

Additive effects of dihydralazine during enflurane or isoflurane hypotensive anaesthesia for spinal fusion.

Sixteen patients (13-38 yr) undergoing spinal fusion for scoliosis under controlled hypotension were studied to determine the haemodynamic and neuroendocrine responses to IV dihydralazine (1.0 mg.kg-1) followed by 0.5 and 1 MAC of enflurane or isoflurane. Twenty minutes after dihydralazine administration mean arterial pressure (-20 per cent) and systemic vascular resistance (-50 per cent) decreased, and cardiac index (+57 per cent), heart rate (+37 per cent) and intrapulmonary shunt increased. Plasma renin activity and aldosterone and norepinephrine levels increased. Further decreases in mean arterial pressure and in systemic vascular resistance were observed when 0.5 MAC enflurane or isoflurane were added. With 1 MAC anaesthetic levels a further decrease in mean arterial pressure was observed in both groups, but pressure fell to a lower level with isoflurane than with enflurane (p less than 0.01). The reduction of arterial blood pressure to a level of 50-60 mmHg for three to four hours was easy to control and was free of complications. The preliminary IV administration of dihydralazine allowed a reduced volatile agent concentration which attenuated undesirable haemodynamic effects, in spite of renin and norepinephrine release, and permitted a rapid intraoperative awakening.

[In vitro evaluation and study of the survival of erythrocytes preserved in a saline-adenine-glucose-mannitol medium for 35 days]. / Evaluation in vitro et étude de survie in vivo des globules rouges conservés en milieu saline-adenine-glucose-mannitol pendant 35 jours.

The saline-adenine-glucose-mannitol (SAGM) solution for resuspension of red cells was evaluated on 30 blood units tested over 42 days and compared to 5 red cell concentrates collected on the conventional CPD medium. Total and extra-cellular hemoglobin, potassium, pH, ATP and DPG concentrations, osmotic fragility, schizocyte formation, and red cell antigenicity were studied through the storage period. Chromium survival studies of autologous donated red cells were performed in 10 donors. Red cell concentrates resuspended in SAGM solution showed at the 35th day of conservation at 4 degrees C, a mean storage hemolysis of only 0.66%, an ATP concentration of 67% of the initial value, a schizocyte proportion of less than 1.5%, a mean 24 hour posttransfusion viability of 88.33% and a mean red cell T 1/2 survival of 25 days 10 hours. No alteration of common blood group antigens could be found after storage of red cells for 42 days.

[Various characteristics of intravenous polyvalent immunoglobulins]. / A propos de certaines caractéristiques des immunoglobulines polyvalentes intraveineuses (GVP).

Polyvalent human immunoglobulins for intravenous use (GVP) are obtained by fractionating human plasma with ethanol, according to a method in which traces of pepsin at pH4 eliminate any anticomplementary activity. All the analytical tests have come within official requirements. Results of extended tests concerning specificity, potency, immunoglobulin subclass distribution, biological half-life and opsonic function are presented. Since their official release for clinical use on July 1st, 1983, almost 15,000 therapeutic units of 2.5 g of immunoglobulins have been consumed without any reported major side effects. Multicenter clinical trials are being carried out with adults and children. Available results confirm very good tolerance, and, as expected, effectiveness for well known and codified indications.

Production of high specific activity 123I for protein iodination for medical use.

Iodine-123 is produced via xenon-133 by irradiation of a sodium iodide target with 108 MeV deuterons from the synchrocyclotron of IPN. The on-line production method is described. The specific activity of the iodine is determined by neutron activation analysis and by a radioimmunological method. The conditions labelling different proteins (insulin, angiotensin) are given and also the purification method to obtain a product ready for injection to patients.

Blood donors positive for HBsAg and negative for anti-HBc antibody.

From January 1980 to December 1983, 989,907 blood donations were screened for HBsAg. A total of 1,345 was found HBsAg positive; 33 of whom were negative for anti-HBc (2.45%); in 10 cases HBeAg was present at a low level along with HBsAg. 2 of the 33 subjects were lost to follow-up. Late serum samples were available for 28 blood donors, and clinical and biological data only were known for the 3 others. An evolution of HBV markers was observed in each case; anti-HBc antibody became positive in 24 subjects (the 4 remaining subjects had a very short follow-up); HBeAg was positive at a high titer in 18 subjects and seroconversion to anti-HBe was observed in 7 individuals; HBsAg concentration increased in 21 subjects from 2 to 4,000 times and decreased in the 7 others. Seroconversion to anti-HBs was observed in 8 individuals. According to these serological, biological and clinical findings, different outcomes were observed: in 6 subjects too short a follow-up was available to allow appropriate classification, but there was evidence to suggest all probably developed clinical hepatitis; in 6 subjects asymptomatic hepatitis with rapid loss of HBsAg occurred; in 2 subjects asymptomatic hepatitis with the persistence of HBsAg at a low level and seroconversion to anti-HBe occurred; and in 17 subjects clinical hepatitis developed. These observations establish that most of the 33 blood donors were infectious at the time of their blood donation, and that anti-HBc antibody screening must not replace HBsAg screening for blood donations.

[Parvovirus (serum-parvovirus-like-virus) and Aurillac antigen. A study of 18 cases]. / Parvovirus (SPLV) et antigène Aurillac. Etude de 18 observations.

Two cases of parvovirus viraemia were observed in 1972 by screening of blood donors for HBs Ag by counter-electrophoresis. This virus was named "Aurillac" from the town in which the first case originated. In London, a virus found in the same circumstances in 1975, was found identical to the Aurillac Ag. The authors named it "serum parvovirus-like virus" (SPLV) or parvovirus B 19. Since 1972, 16 additional cases have been observed in Paris. Among these 18 cases, 11 were blood donors, 4 were hospital staff and 3 were patients. Second serum samples were available for 13 of the 18 cases. Seroconversion has been detected in all except one, a patient with lymphosarcoma. Antibody could be observed within few days. Anti-Aurillac antibody was found by CEP in 25,3% of blood donors. Examination of antigen positive sera by immune electron microscopy using a late serum sample showed aggregates of spherical particles measuring 20 nm in diameter. The antigen banded in caesium chloride at a density of 1.38. Ten of the 15 healthy adults could be interviewed: 7 appeared symptomless, 1 had a fever up to 39 degrees C for one day, 2 had erythema (as well as 3 subjects who had been in contact with these 2 persons). These cases are discussed and compared to the British literature showing that this virus could provoke the fifth disease or erythema infectiosum and aplastic crisis in chronic hemolytic syndromes. This virus could contaminate clotting factors.

Effect of whole-body irradiation on phagocytic activity of rat alveolar macrophages.

The phagocytic activity of rat alveolar macrophages was studied in vitro for up to six weeks after whole-body gamma irradiation (7.5 Gy). Ingestion of fluorescent latex microspheres was evaluated using both microscopic examination and flow cytometric quantitation. After a transient decrease on first day post-irradiation, a slight increase in the phagocytic ability was observed from day 14 to day 28, with a maximum on day 21. From day 35 onwards, phagocytic capacities returned approximately to those of the controls. The percentage of phagocytic cells (cells having ingested one microsphere or more) increased by 75 per cent on day 21 after irradiation and the phagocytic index (percentage of phagocytic cells X the average number of ingested microspheres per cell) increased by 250 per cent while at the same time, the number of recovered alveolar cells decreased by 37 per cent. The augmentation of phagocytic capacities after irradiation was particularly characterized by an increase in the percentage of cells ingesting more than five microspheres. Flow cytometric studies showed a significant increase in mean cell size on day 21 post-irradiation. The augmentation of the phagocytic activity was not found when macrophages from control rats were incubated with serum or alveolar lavage fluid from an irradiated donor. Augmentation of phagocytic capacity was also observed after 8.5 Gy but no effect could be observed after 6.5 Gy.