Eye dominance modulates visuospatial attention

Visuospatial attention has an inherent asymmetry: the leftward bias called pseudoneglect. In typical line bisection tasks, healthy individuals tend to judge the center of a line leftward of the true center, an effect attributed to the right hemisphere dominance in visuospatial attention. Since it has been shown that information perceived by the dominant eye strongly activates the ipsilateral visual cortex, we hypothesized that eye dominance may modulate visuospatial attention bias. Because activation of the left hemisphere induced by left eye dominance should mitigate the right hemisphere dominance in attention, we predicted that right-handed individuals with left dominant eye would show smaller amount of pseudoneglect than right-handed individuals with right dominant eye. We compared the performance at both the perceptual (Landmark) and manual line bisection task of forty right-handed healthy individuals, half of whom had a right dominant eye and the other half a left dominant eye. As predicted, the left eyed dominant group showed smaller, actually not significant pseudoneglect, which was thus greater in the right eye dominant group. The influence of eye dominance on visuospatial attention was present in the Landmark but not the manual line bisection task, in which the amount of visuospatial bias correlated with participants' degree of (right) handedness. This is the first report of the effect of eye dominance on visuospatial attention within a right-handed population. This finding, by showing the influence of eye dominance on visuospatial cognition, not only helps in better defining intact visuospatial cognition mechanism but also encourages further research to pinpoint the neural basis of such interaction.

[Partial nephrectomy for renal masses >7cm: Morbidity, oncological and functional outcomes (UroCCR-7 study)]

OBJECTIVES

To describe the morbidity, mortality, oncological and functional results of Partial nephrectomy (PN) for the treatment of renal tumors of more than 7cm.

MATERIAL AND METHODS

Thirty-seven partial nephrectomies for tumors larger than 7cm operated in a single center between 1987 and 2016 were analyzed retrospectively. The pre, per and postoperative clinico-biological data were collected within the UroCCR database. The GFR was assessed at day 5, 1 month and last follow-up. Intraoperative and postoperative surgical complications, the recurrence rate and the overall and specific mortality were collected.

RESULTS

The mean age of the patients was 57 years (44-68). The preoperative GFR and the median tumor size were 80mL/min and 8cm, respectively. The indication for surgery was elective in 21 cases (60%) and 19 tumors (54%) were malignant. Postoperative complications occurred in 24,3 cases (24.3%). The median post-operative GFR was respectively 77mL/min, 80mL/min and 77mL/min at day 5, 1month and at last follow-up. With a median follow up of 31 months [1-168], 5 patients (26,3%) had metastatic progression of whom 1 (5.3%) had a concomitant local recurrence and 3 (15.8%) had died from cancer.

CONCLUSION

This study confirms the feasibility of PN for large tumors with acceptable morbidity, limited risk of local recurrence and excellent functional results.

LEVEL OF EVIDENCE

4.

Preservation of fertility in surgery of benign and borderline malignant ovarian tumors

Benign ovarian tumors occur in 7% of women during their procreative years and involve both organic and functional tumors. The average age of onset for borderline ovarian tumors is ten years younger than that for ovarian cancers. Women with benign and borderline malignant ovarian tumors are therefore more likely to be affected by fertility issues. The causal link between infertility and benign ovarian tumor stems more from the therapeutic strategies adopted than from the histological nature of the benign ovarian tumor. The question of fertility preservation must therefore be addressed in the management of these patients through respect for "correct" surgical indications, through gestures centered around ovarian preservation, and finally, if necessary, by recourse to fertility preservation techniques.

What are the likely IVF/ICSI outcomes if there is a discrepancy between serum AMH and FSH levels? A multicenter retrospective study

OBJECTIVE

The principal outcome was to assess the ovarian response to controlled hyperstimulation during in vitro fertilization (IVF) with or without micro-injection (ICSI) in patients whom ovarian reserve testing revealed a discrepancy between the serum levels of FSH and AMH. The secondary outcome was to determine whether AMH and FSH profiles could predict the IVF/ICSI response.

STUDY DESIGN

This was a multicenter, retrospective study analysing all controlled ovarian hyperstimulation cycles with attempted fresh embryo transfer(s) carried out during IVF/ICSI treatment and in which the AMH level had been assayed between January 01, 2008 and December 31, 2011. This enabled us to form 2 control groups (NOR, normal ovarian reserve: normal AMH and FSH and DOR, diminished ovarian reserve: diminished AMH, increased FSH) and 2 study groups (DAMH: diminished AMH, normal FSH and NAMH: normal AMH, increased FSH). The principal assessment criterion was quantitative ovarian response to stimulation defined by the mean number of oocytes punctured, the secondary assessment criterion the qualitative response to stimulation defined by the pregnancy rate per cycle.

RESULTS

We were able to analyse 1803 stimulation cycles. The mean number of oocytes punctured was significantly reduced in the DAMH and DOR groups compared to the NAMH and NOR groups (5.2±3.9 and 4.1±3.3 vs. 11.5±7 and 9.5±5.6, respectively [P<0.01]). The pregnancy rate per initiated cycle was significantly reduced in the DAMH and DOR groups compared to the NAMH and NOR groups (20% and 24% vs. 32 and 35%, respectively [P<0.01]). Live birth rates did not differ between the groups however. Multivariate analysis with logistic regression revealed that AMH, FSH and age independently had an effect on the number of oocytes punctured, although the effect exerted by AMH seemed to be preponderant (OR: 2.75: 95%CI [2.39-3.19]). AMH appeared to be the sole factor independently predictive of pregnancy per cycle.

CONCLUSION

The serum AMH level appears to provide an additional item of discriminatory information, which should not be overlooked. Ovarian reserve work-up should include routine AMH assay.

[Patient's experience of topical anesthesia by lidocaine vaginal gel for oocyte retrieval]

A recent adverse effect of a paracervical block (cardiac arrest) occurred during an oocyte retrieval (OR), forcing us to reconsider our pain management during OR. Since then, we decided to use intravaginal lidocaine gel as analgesia during OR.

OBJECTIVES

To evaluate the pain during OR after intravaginal lidocaine gel analgesia and to evaluate the motivations of women choosing this technique.

METHODS

A monocentric observational study was performed on 200 patients. Pain was measured using a numeric pain scale during and after oocyte retrieval. The tolerance of the procedure was evaluated through a patient questionnaire.

RESULTS

Median maximal pain was 5±2.3 (0-10) per-retrieval and 3±2.2 (0-10) post-retrieval. The procedure was considered bearable by 85.5% of the patients and 81.5% of them would choose this method in case of new oocyte retrieval. No adverse effect occurred during the study.

CONCLUSION

The use of intravaginal lidocaine gel seems an acceptable analgesia alternative during oocyte retrieval.

Preoperative localization of an insulinoma: selective arterial calcium stimulation test performance

PURPOSE

Preoperative localization of an insulinoma is recommended to improve the cure rate, but non-invasive procedures can fail to detect the tumour. The objective of the study was to assess the performance of a selective arterial calcium stimulation test in the preoperative localization of insulinomas that were not detected by conventional imaging procedures.

METHODS

We conducted a monocenter retrospective case review of 13 patients who had endogenous hyperinsulinism and were treated between 1994 and 2013. Patients were selected on the basis of negative or doubtful non-invasive preoperative imaging. A selective arterial calcium stimulation test was performed by pancreatic and hepatic arteriography with selective intra-arterial calcium stimulation and hepatic venous sampling in order to obtain the plasma insulin measurement. We evaluated the efficacy of the test by comparing the results with an endoscopic ultrasound.

RESULTS

Twelve of the 13 patients underwent surgery, and the presence of an insulinoma was proven in 11 patients by pathological analysis of the tumour. An endoscopic ultrasound was consistent with surgery in 71.4 % of cases, while selective arterial calcium stimulation was consistent with surgery in 90.9 % and allowed detection of an insulinoma in two additional patients with a negative endoscopic ultrasound. One false-negative and one false-positive arterial calcium test were observed. No adverse events were recorded except transient skin flush following calcium injection in one patient.

CONCLUSION

The selective arterial calcium stimulation test is a sensitive diagnostic procedure for localizing insulinomas and may be considered when non-invasive radiological imaging does not allow the detection of an occult insulinoma.

[MRI-guided breast microbiospy or macrobiopsy: which is the best option for a small tumor?]

The choice of the optimum therapeutic strategy for breast cancer depends on the histological diagnosis of the sample obtained by biopsy. The microbiopsy is the preferred method as it provides an accurate diagnosis of the histological type as well as the main prognostic factors, whilst being simple, fast and inexepensive. However, some infraclinic breast tumors are not accessible by conventional guidance due to excessive depth inside the breast, their small size or technical inability to image them by mammography or ultrasonography. In those cases, the MRI guidance may help to perform the biopsy. Most MRI biopsies are made by large-core needle that are known to alter the histological structure of the tumor and to disturb the anatomopatholgical analysis (size and surgical margin). Those are very important elements to know before treatment. Our case report details an original technique of MRI microbiopsy of a deep 4mm opacity found on the occasion of a patient's mammography. The operative specimen revealed an invasive ductal carcinoma of 4mm diameter which scored III on the Elston and Ellis scale (oestrogen and progesterone receptors tested negative and HER-2 was over-expressed). It was associated with a high grade in situ ductal carcinoma. No systemic treatment was prescribed due to the small size of the carcinoma. The development of partially or totally amagnetic microbiopsy pistols would help perform microbiopses guided by MRI.

[Breast cancer after Hodgkin disease]

Secondary breast cancer represents 6 to 9% of secondary neoplasia after treatments for Hodgkin Disease (HD). Mostly, they appear 10 years after the end of treatments for HD. The most important risk factors are mantle field irradiation and the young age. The means of screening and treatments are still in discussion. We report a case of bilateral intraductal and invasive carcinoma that occurred 16 years after treatments for HD, developing its particularities in diagnosis and treatment, particularly place of conservative treatments and sentinel lymph node biopsy.

[Pregnancy-related deaths. Genesis of the concept and methodological aspects]

Within the past 10 years, the outlook on the causes underlying maternal deaths has evolved, with the advent in the last "International classification of diseases" of the concepts of late maternal mortality and pregnancy-related mortality. Those concepts have led to an enlargement of the field, in terms of the range of causes as well as of the length of the time period at risk. Causes of death traditionally considered as "fortuitous" are now included in the count, given that the notion of pregnancy-related mortality covers all deaths occurring during pregnancy or at the latest one year after pregnancy termination, whatever the cause. Given this background, we critically review the definitions and classification systems of deaths of pregnant or post-partum women, and discuss the philosophy underlying these conceptual changes, and their consequences in terms of data collection and measurement issues.

Eimeria tenella microneme protein EtMIC3: identification, localisation and role in host cell infection

The gene coding for Eimeria tenella protein EtMIC3 was cloned by screening a sporozoite cDNA library with two independent monoclonal antibodies raised against the oocyst stage. The deduced sequence of EtMIC3 is 988 amino acids long. The protein presents seven repeats in tandem, with four highly conserved internal repeats and three more divergent external repeats. Each repeat is characterised by a tyrosine kinase phosphorylation site, WRCY, and a reminiscent motif of the thrombospondin1 (TSP1)-type I domain, CXXXCG. The protein EtMIC3 is localised at the apex of free parasite stages. It is not detected in the early intracellular parasite stage but is synthesised in mature schizonts. Secretion of the protein is induced when sporozoites are incubated in complete medium at 41 degrees C. Strangely enough, the two independent mAb that allow cloning of EtMIC3 interfere with parasitic growth in different ways. One is able to inhibit parasite invasion whereas the other inhibits development. Expression and localisation of the protein EtMIC3 are consistent with a protein involved in the invasion process as is expected for a microneme protein.

Peripheral blood stem cell collection in 24 low-weight infants: experience of a single centre

Peripheral blood stem cells (PBSC) harvest may be difficult in young children. Extracorporeal separator line priming by red blood cells is usually required to improve haemodynamic tolerance and efficacy of collection. We present our experience with 24 children weighing less than 15 kg treated between January 1997 and September 1999, in whom we tried to avoid systematic blood priming. The median age and weight at the time of apheresis were 2.4 years and 12 kg, respectively. A total of 48 PBSC were performed. When haemoglobin was less than 12 g/dl, packed red cells were transfused before collection (40% of aphereses). The median cell yield per apheresis was 7.1 (2.2-30.6)x10(6)/kg CD34(+) cells and 16.0 (3.3-44.3)x10(5) CFU-GM/kg. Initial collection failed in three cases. Four children required an additional haematopoietic progenitor mobilization. This procedure allowed PBSC collection without transfusion in 37.5% of children, and was safe (two serious and five mild transient side effects) and effective (median CD34(+) cells collected per child: 7.1 x 10(6)/kg (4.6-30.6) and CFU-GM: 15.1 x 10(5)/kg (4.7-44.3)). Despite their low weight, insertion of a femoral catheter was avoided in 43% of children.

[Imaging of skull base tumors in adults]

The skull base is divided into three parts: anterior, central and posterior. Numerous foramina are located in the skull base and transmit important neurovascular structures. Numerous types of tumor can be observed at the skull base. They are classified as anterior, central and posterior skull base tumors. They are also divided into three groups according to their origin: tumors arising from the skull base itself, intracranial tumors and extracranial tumors invading the skull base. Imaging is very important for diagnosis, treatment and follow-up of patients with skull base tumors. Magnetic resonance imaging is the most useful modality as it visualizes the lesion on different planes and permits the planning of therapy. Computed tomography depicts the osseous lesions more precisely and may be necessary before surgery. Catheter angiography is now in most cases replaced by magnetic resonance angiography. Interventional neuroradiology is necessary if the lesion is highly vascularized or if a vessel is encased in the tumor.

Early head movements elicited by visual stimuli or collicular electrical stimulation in the cat

During the course of previous recordings of visually-triggered gaze shifts in the head-unrestrained cat, we occasionally observed small head movements which preceded the initiation of the saccadic eye/head gaze shift toward a visual target. These early head movements (EHMs) were directed toward the target and occurred with a probability varying between animals from 0.4% to 16.4% (mean=5.2%, n=11 animals). The amplitude of EHM ranged from 0.4 degrees to 8.3 degrees (mean=1.9 degrees ), their latency from 66 to 270 ms (median=133 ms) and the delay from EHM onset to gaze shift onset averaged 183+/-108 ms (n=240). Their occurrence did not depend on visual target eccentricity in the studied range (7-35 degrees ), but influenced the metrics and dynamics of the ensuing gaze shifts (gain and velocity reduced). We also found in the two tested cats that low intensity microstimulation of the superior colliculus deeper layers elicited a head movement preceding the gaze shift. Altogether, these results suggest that the presentation of a visual target can elicit a head movement without triggering a saccadic eye/head gaze shift. The visuomotor pathways triggering these early head movements can involve the deep superior colliculus.

Gaze shifts evoked by electrical stimulation of the superior colliculus in the head-unrestrained cat. II. Effect of muscimol inactivation of the caudal fastigial nucleus

The medioposterior cerebellum [vermian lobules VI and VII and caudal fastigial nucleus (cFN)] is known to play a major role in the control of saccadic gaze shifts toward a visual target. To determine the relative contribution of the cFN efferent pathways to the brainstem reticular formation and to the superior colliculus (SC), we recorded in the head-unrestrained cat the effects of cFN unilateral inactivation on gaze shifts evoked by electrical microstimulation of the deeper SC layers. Gaze shifts evoked after muscimol injection still exhibited the typical qualitative features of normal saccadic gaze shifts. Nevertheless, consistent modifications in amplitude and latency were observed. For ipsiversive movements (evoked by the SC contralateral to the inactivated cFN), these changes depended on the locus of stimulation on the motor map: for the anterior 2/3 of the SC, amplitude increased and latency tended to decrease; for the posterior 1/3 of the SC, amplitude decreased and latency increased. For the contraversive direction, amplitude moderately decreased and latency tended to increase for all but the caudal-most stimulated SC site. These modifications of SC-evoked gaze shifts during cFN inactivation differed from the ipsiversive hypermetria/contraversive hypometria pattern observed for visually triggered gaze shifts recorded during the same recording sessions. We conclude that (i) the topographical organization of gaze shift amplitude in the deeper SC layers is influenced by the cerebellum and is either severely distorted or demonstrates an amplitude reduction during inactivation of the contralateral or ipsilateral cFN, respectively; (ii) gaze shifts evoked by SC microstimulation and visually triggered gaze shifts either rely on distinct cerebellar-dependent control processes or differ by the location of the caudal-most active SC population. We present a functional scheme providing several predictions regarding the modulatory influence of the cerebellum on SC neuronal activities and on the topographical organization of fastigial-SC projections.

Gaze shifts evoked by electrical stimulation of the superior colliculus in the head-unrestrained cat. I. Effect of the locus and of the parameters of stimulation

Several studies have suggested that the pattern of neuronal activity in the superior colliculus (SC) interacts with the well-known topographical coding of saccades (motor map). To further describe this interaction, we recorded gaze saccades evoked by electrical microstimulation of SC deeper layers in the head-unrestrained cat and systematically varied the collicular locus (25 sites) and parameters (intensity, frequency) of the stimulation. Long stimulation trains were used to avoid saccade truncation. We found that the direction and amplitude of evoked gaze shifts were related to the stimulation locus, describing a gaze shift map. For 18 out of 20 sites the amplitude, but not the direction, also strongly depended on stimulation strength. Indeed, gaze amplitude continuously increased when raising current intensity up to several times the threshold value T (the largest intensity tested was 6 x T), whereas varying pulse frequency from 150 to 750 pulses per second (p.p.s.) revealed an optimal frequency range (300 and 500 p.p.s.) eliciting the largest gaze shifts. Moreover, the intensity effect on amplitude increased in an orderly fashion with the rostro-caudal stimulation locus. Gaze shift amplitude was not related to the number of delivered stimulation pulses. Concerning movement initiation, increasing either intensity or frequency led to an exponential decrease in gaze latency until minimal values near 30 ms were reached, but the number of pulses delivered during the corresponding latency period remained constant within a 300-500 p.p.s. frequency range. These findings indicate that the pattern of collicular discharge evoked by electrical stimulation strongly interacts with the gaze shift map and provide evidence for a summation of collicular activities by downstream premotor neurons.

Production of amarogentin in root cultures of Swertia chirata

Conventional and Agrobacterium rhizogenes-transformed root cultures were studied with respect to growth and amarogentin content following cultivation in various growth media. The fastest growth rate was observed using Nitsch medium. The best amarogentin content was obtained after cultivation in root culture (RC) medium for which the slowest growth rate was noticed. Addition of sucrose at 6% and 9% (w/v), respectively, also resulted in better growth rates and increased total but unaltered relative amarogentin content compared to 3% (w/v) sucrose. No change in amarogentin content was observed upon addition of elicitors, putative precursors of amarogentin biosynthesis, and plant growth hormones with the exception of salicylic acid and chitosan: at 100 mM salicylic acid a reduction and at 25 mg/L chitosan an increase of amarogentin were observed at significant levels. The cultivation of S. chirata roots in a 2-L stirred-tank bioreactor was successful only with a stainless-steel mesh fitted inside the culture vessel for immobilization of the roots. A 15-fold enhancement of amarogentin content in the medium was achieved by a root permeabilisation treatment using Tween 20 at 1.3% (v/v) final concentration in the bioreactor.

Identification of linear viscoelastic constitutive models

Accelerations induce in the brain mechanical stresses that may explain the loss of consciousness feared by fighter pilots. In this study, the brain is modelled as a multi-domain structure and a finite element method is used to identify the constitutive law parameters of each domain and then to analyse the stress level in the brain. The loading and observed strain rates induced by hypergravity seem to indicate a quasi-static behaviour of the brain structure. A general procedure has been developed to characterise the behaviour of a structure including several domains. Each of them is assumed to be isotropic and homogeneous with a linear viscoelastic behaviour. These constitutive laws were identified using only the displacements of several nodes on the envelope discarding the displacements between domains at the interaction surfaces. These interfaces may be buried inside the structure and not connected with the external surface. Two validation examples are proposed to show the reliability and effectiveness of the method.

Altered visuo-motor behavior during inactivation of the caudal fastigial nucleus in the cat

It is known that the medio-posterior cerebellar lobules VI/VII of the vermis and caudal part of the fastigial nucleus (cFN) are involved in the control of saccadic displacements of the visual axis in space (gaze). We have recently shown in the head-unrestrained cat that inactivation of the cFN severely impairs the accuracy of orienting gaze shifts toward visual targets by altering the amplitude of both eye and head components. In the present paper, we report additional data that indicate that the deficits induced by cFN inactivation are not restricted to saccadic gaze shifts but extend to the forward reaching movement of the whole body toward a visual target. Indeed, the path followed by the animal walking toward a visible food target was systematically curved toward the inactivated side. This deficit could largely be accounted for by an angular bias in the heading direction used by the animal to reach the target. These data suggest that pharmacological inactivation of the cFN leads to a general deficit in spatial orientation.

Evaluation of cerebral stresses under acceleration taking into account the lateral ventricles

In certain flight configurations, fighter pilots are exposed to high Gz acceleration that may induce inflight loss of consciousness (LOC). That LOC is usually preceded by visual prodromes as greyout and blackout. The pathophysiological cause of these phenomena is used to be related to the effects of accelerations on the vascular system (Burton, 1988; Whinnery, 1990). However technological advances have created aircraft generating high accelerations with rapid onset rates (1-6 Gs-1). The symptomatology of inflight LOC has changed and prodromes no longer appear. Pilots also reported a lacunar amnesia of the LOC. In order to evaluate the potentially adverse effect of acceleration on the brain tissue, it was important to study its mechanical behavior under hypergravity. An approximation of the cerebral stresses was obtained by coupling an 'ex vivo' experiment (Guillaume et al., 1997) with a numerical simulation. Firstly, the calculations have been realized considering the brain as homogeneous. Secondly, the cerebral ventricles have been individualized. The results of these two approaches were compared.

[Anaphylactic shock caused by fibrin glue]

We observed a case of anaphylactic shock in a 68-year-old woman after a nasal intramucosal injection of fibrin glue for telangiectasies therapy. The tests showed an allergy to aprotinin contained in the glue. In the previous years, glue and aprotinin had been administered to the patient several times for nasal bleeding.

Compensation for gaze perturbation during inactivation of the caudal fastigial nucleus in the head-unrestrained cat

Muscimol injection in the caudal part of the fastigial nucleus (cFN) leads, in the head-unrestrained cat, to a characteristic dysmetria of saccadic gaze shifts toward visual targets. The goal of the current study was to test whether this pharmacological cFN inactivation impaired the ability to compensate for unexpected perturbations in gaze position during the latency period of the saccadic response. Such perturbations consisted of moving gaze away from the target by a transient electrical microstimulation in the deep layers of the superior colliculus simultaneously with extinction of the visual target. After injection of muscimol in the cFN, targets located in the contralesional hemifield elicited gaze shifts that fell short of the target in both "perturbed" and "unperturbed" trials. The amplitude of the compensatory contraversive gaze shifts in perturbed trials coincided with the predicted amplitude of unperturbed responses starting from the same position. Targets located in the opposite hemifield elicited hypermetric gaze shifts in both trial types, and the error of compensatory responses was not statistically different from that of unperturbed gaze shifts. These results indicate that inactivation of the cFN does not interfere with the ability of the head-unrestrained cat to compensate for ipsiversive or contraversive perturbations in gaze position. Thus the gaze-related feedback signals that are used to compute a reference signal of desired gaze displacement are not impaired by cFN inactivation.

Contribution of the rostral fastigial nucleus to the control of orienting gaze shifts in the head-unrestrained cat

The implication of the caudal part of the fastigial nucleus (cFN) in the control of saccadic shifts of the visual axis is now well established. In contrast a possible involvement of the rostral part of the fastigial nuceus (rFN) remains unknown. In the current study we investigated in the head-unrestrained cat the contribution of the rFN to the control of visually triggered saccadic gaze shifts by measuring the deficits after unilateral muscimol injection in the rFN. A typical gaze dysmetria was observed: gaze saccades directed toward the inactivated side were hypermetric, whereas those with an opposite direction were hypometric. For both movement directions, gaze dysmetria was proportional to target retinal eccentricity and could be described as a modified gain in the translation of visual signals into eye and head motor commands. Correction saccades were triggered when the target remained visible and reduced the gaze fixation error to 2.7 +/- 1.3 degrees (mean +/- SD) on average. The hypermetria of ipsiversive gaze shifts resulted predominantly from a hypermetric response of the eyes, whereas the hypometria of contraversive gaze shifts resulted from hypometric responses of both eye and head. However, even in this latter case, the eye saccade was more affected than the motion of the head. As a consequence, for both directions of gaze shift the relative contributions of the eye and head to the overall gaze displacement were altered by muscimol injection. This was revealed by a decreased contribution of the head for ipsiversive gaze shifts and an increased head contribution for contraversive movements. These modifications were associated with slight changes in the delay between eye and head movement onsets. Inactivation of the rFN also affected the initiation of eye and head movements. Indeed, the latency of ipsiversive gaze and head movements decreased to 88 and 92% of normal, respectively, whereas the latency of contraversive ones increased to 149 and 145%. The deficits induced by rFN inactivation were then compared with those obtained after muscimol injection in the cFN of the same animals. Several deficits differed according to the site of injection within the fastigial nucleus (tonic orbital eye rotation, hypermetria of ipsiversive gaze shifts and fixation offset, relationship between dysmetria and latency of contraversive gaze shifts, postural deficit). In conclusion, the present study demonstrates that the rFN is involved in the initiation and the control of combined eye-head gaze shifts. In addition our findings support a functional distinction between the rFN and cFN for the control of orienting gaze shifts. This distinction is discussed with respect to the segregated fastigiofugal projections arising from the rFN and cFN.

Orienting gaze shifts during muscimol inactivation of caudal fastigial nucleus in the cat. II. Dynamics and eye-head coupling

We have shown in the companion paper that muscimol injection in the caudal part of the fastigial nucleus (cFN) consistently leads to dysmetria of visually triggered gaze shifts that depends on movement direction. Based on the observations of a constant error and misdirected movements toward the inactivated side, we have proposed that the cFN contributes to the specification of the goal of the impending ipsiversive gaze shift. To test this hypothesis and also to better define the nature of the hypometria that affects contraversive gaze shifts, we report in this paper on various aspects of movement dynamics and of eye/head coordination patterns. Unilateral muscimol injection in cFN leads to a slight modification in the dynamics of both ipsiversive and contraversive gaze shifts (average velocity decrease = 55 degrees/s). This slowing in gaze displacements results from changes in both eye and head. In some experiments, a larger gaze velocity decrease is observed for ipsiversive gaze shifts as compared with contraversive ones, and this change is restricted to the deceleration phase. For two particular experiments testing the effect of visual feedback, we have observed a dramatic decrease in the velocity of ipsiversive gaze shifts after the animal had received visual information about its inaccurate gaze responses; but virtually no change in hypermetria was noted. These observations suggest that there is no obvious causal relationship between changes in dynamics and in accuracy of gaze shifts after muscimol injection in the cFN. Eye and head both contribute to the dysmetria of gaze. Indeed, muscimol injection leads to parallel changes in amplitude of both ocular and cephalic components. As a global result, the relative contribution of eye and head to the amplitude of ipsiversive gaze shifts remains statistically indistinguishable from that of control responses, and a small (1.6 degrees) increase in the head contribution to contraversive gaze shifts is found. The delay between eye and head movement onsets is increased by 7.3 +/- 7.4 ms for contraversive and decreased by 8.3 +/- 10.1 ms for ipsiversive gaze shifts, corresponding respectively to an increased or decreased lead time of head movement initiation. The modest changes in gaze dynamics, the absence of a link between eventual dynamics changes and dysmetria, and a similar pattern of eye-head coordination to that of control responses, altogether are compatible with the hypothesis that the hypermetria of ipsiversive gaze shifts results from an impaired specification of the metrics of the impending gaze shift. Regarding contraversive gaze shifts, the weak changes in head contribution do not seem to reflect a pathological coordination between eye and head but would rather result from the tonic deviations of gaze and head toward the inactivated side. Hence, our data suggest that the hypometria of contraversive gaze shifts also might result largely from an alteration of processes that specify the goal rather than the on-going trajectory, of saccadic gaze shifts.

Effects of perfusion on the mechanical behavior of the brain-exposed to hypergravity

In certain flight configurations, fighter pilots are exposed to high Gz acceleration which may induce inflight loss of consciousness (G-LOC). In order to study the mechanical effects induced by these accelerations on the cerebral structures, an experimental model has been developed in vitro. Fresh bovine brains were excised and placed in a transparent mold modeling the inside of the skull. Half of these brains were perfused during the experiment. This assembly was placed into the gondola of a centrifuge, in front of a camera lens. Displacements and deformations of the brains were filmed and recorded at different onset rates. Measurements were made after off-line digitalization of images. Experimental data were incorporated into a finite element calculation code whose mesh represented the brain. The applied behavior law was elastic, the structure being considered as homogeneous and isotropic. The first results concerned the elastic properties of the brains under hypergravity. The mean value of the Young's modulus of the nonperfused brain was 46.8 kPa, which corresponded to the values published in reference literature. For the perfused brains, the mean value of the Young's modulus was higher. The mean value of the equivalent Poisson's ratio was 0.35. In fact, contrary to impacts, the mechanical stimulation is long enough to allow fluid displacements. The mean value of the equivalent Poisson's ratio calculated in the present study should probably be increased since this study was performed post mortem.

[Delayed low back pain after spinal anesthesia]

A 50-year-old man had an inguinal hernia repair under spinal anaesthesia with bupivacaine. On the 2nd postoperative day, he complained of backache and paresis at the posterior part of the lower extremities, well relieved by non-steroidal anti-inflammatory drugs. On the 6th postoperative day, he came back to hospital, because of low back pain associated with a heavy feet sensation. The hypothesis of a neurological complication of the spinal anaesthesia was considered. The interview of the patient revealed a history of lumbar disk disease, not reported during the preoperative visit. After an in depth clinical examination, two causes seemed possible: subarachnoid haematoma and lumbar disk protusion. Against the first diagnosis were the initial clinical signs. However, in many cases, objective neurological deficit arise too late to allow efficient neurosurgical treatment. Thus, a MRI examination was performed which is non invasive in comparison with a computed tomography myelogram. In our patient, it did not detect a true lumbar disk protusion, but a simple degenerative disease of the L5-S1 disk. In suppressing the lumbar lordosis, spinal anaesthesia probably allowed a distension of spinal capsules and tendons, responsible for the troubles.

[Measurement of tympanic temperature by infrared and thermocouple thermometry. A comparative study]

OBJECTIVE

To compare tympanic temperatures obtained with an infrared thermometer Core Check 2090A (IVAC), non in contact with the tympanic membrane, to values obtained with a thermocouple thermometer Mon-A-Therm (Mallinckrodt) in contact with it, and to assess whether the differences depend on the person measuring the temperature.

STUDY DESIGN

Prospective comparative open study.

PATIENTS

The study included 150 adults in whom the tympanic temperatures were measured at their admission to recovery room by 10 nurse anaesthetists.

METHODS

Each thermometer was inserted in the same patient into an external acoustic meatus. The median and range of the temperature differences were used to assess the bias and the accuracy of the measures. Their reliability was analyzed with consideration of the measuring person and the presence of irrelevant values, defined as a temperature difference over 0.3 degrees C.

RESULTS

The temperatures obtained with both devices were similar (36.2 +/- 0.7 degrees C with IVAC thermometer vs 36.2 +/- 0.8 degrees C with Mallinckrodt thermometer). The median value of the differences was 0 degrees C, with a range of 2.5 degrees C (maximum value + 1.5 degrees C, minimum value: -1 degree C). Nineteen patients could be qualified as hypothermic (temperature < 36.5 degrees C) with one thermometer and normothermic (temperature > or = 36.5 degrees C) with the other. Among them, only 9 (6%) had temperature differences above 0.3 degrees C. The temperature differences were not different according to the measuring nurse. Nevertheless two of them obtained major differences or irrelevant figures.

CONCLUSIONS

As compared to the thermocouple thermometry, infrared thermometry has no bias but a low precision. The measurement error does not allow the recognition of hypothermia in 6% of patients. The error may be made by the measuring person and/or related to the anatomy and the patency of the external acoustic meatus. Tympanic infrared thermometry seems to be a convenient method for temperature measurements at short time intervals in the recovery room, provided its limitations are kept in mind.

[Therapeutic strategy in 46 cases of radiation injury of the intestine]

Our expérience in the treatment of 46 cases with radiation enteritis (RE) permitted to summarize 5 key points in the Surgical Strategy: laparotomy incision, enterolysis technique, small bowel and colon preservation, anastomosis technic and parenteral nutritional support. Surgery is imposed most of the time in digestive and nutritional Insufficiencies due to radiation enteritis. 46 patients aged to 33-81 years (mean age = 59) were included for possible surgery. The first clinical digestive symptoms were occlusion (n = 39) and/or digestive fistula (n = 7) and/or perforation (n = 3). These abnormalities were often associated with severe malnutrition (weight loss > or = 20% of usual weight) inducing surgery preparation with pre-operative parenteral nutrition (8 to 350 days). 3 patients were not operated because of general problems and lived 1 to 7 months after the beginning of parenteral nutrition. For operated patients (n = 43), 12 underwent 2 operations (resection and/or enteral liberation) and one patient underwent 4 surgical interventions because of digestive fistula. In 35 cases, small bowel resection was performed leaving 135.4 +/- 62.6 cm of intestine (0 to 225 cm of jejunum and/or ileum) and in 13 cases, complete enterolysis was achieved. All the patients received a post-operative parenteral nutrition during 1 to 23 months (median = 6.2 +/- 5.3 months). 31 patients received home parenteral nutrition during the pre and/or post-operative phase for a median duration of 6.3 +/- 3.2 months (range: 1-23 months). 4 patients died during the immediate post-operative phase and among them, 3 died after the second surgery. 12 deaths were observed due to the primary cancer and 6 due to the evolution of radiation lesions. Median survival of patients without cancer evolution reach 180 months with a 5-year survival rate of 94% (Kaplan-Meier method). In patients with radiation enteritis, the pre and post-operative nutritional support associated with radical surgery allows to obtain prolonged survival in non cancer patients.

Modeling and numerical simulation of the cerebral blood flow under acceleration

When fighter aircrafts change directions, the pilots are subject to a centrifuge force. This force can be enough to induce the pilot loss of consciousness (LOC). The physiological cause of this LOC is a brain hypoxia which results from the increase of the hydrostatic pressure. Under gradual onset rate + Gz acceleration (GOR+Gz), the brain hypoxia occurs with visual prodromes familiar to fighter pilots. In this case, they feel a reduction of the peripheral vision (Grey-out), followed by a loss of the central vision (Black-out). The useful time of consciousness can be prolonged by using anti-G suit. Under rapid onset rate +Gz acceleration, a new symptomatology of the LOC, characterized by the absence of a grey or black-out, has been observed. The objective of this theoretical study is a better understanding of mechanisms which cause fighter pilot inflight LOC. A physical model has been developed. It allows to take into account the influence of the rate of change in acceleration on the cerebrovascular system behavior.

[Acute respiratory distress caused by a mediastinal pancreatic pseudocyst]

The pseudocyst of the pancreas is a frequent complication of acute pancreatitis. However to intrathoracic localization remains exceptional. A case of acute respiratory insufficiency in a 66-year-old man in whom artificial ventilation was required for such a complication is reported. This case stresses the difficulty often encountered for the differential diagnosis of these liquid tumors. The clinical signs are variable and non specific, especially in case of absence of any history of pancreatitis. The radiographic studies, in particular ultrasonography and CT-scanner defines its liquid nature and its connections. Endoscopy examination confirms its retro-oesophageal extension due to the migration through the oesophageal hiatus. Only the percutaneous needle aspiration of a collection or an associated pleural effusion confirms the diagnosis by the high content of amylases. The treatment of this type of localisation is surgical and essentially consists of an internal derivation.