[Decompression accident under apnea].
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Apnea↗
Biomedical subjects
B Grandjean
Publications and source records attributed to B Grandjean.
[Angiotensin-converting enzyme inhibitors and pregnancy. Apropos of 2 cases].
Angiotensin converting enzyme inhibitors do not have any teratogenic effect in man but their use during pregnancy has led to cases of hypotension and subsequent severe renal failure in the newborn. The authors report two cases, one involving a twin pregnancy which illustrate the variability of the foetal involvement. It is emphasized that the side effects of angiotensin converting enzyme inhibitors are not only reversible but also are not constantly found.
Adult↗
Long-term dysfunctions of neural stereoscopic mechanisms after unilateral extraocular muscle proprioceptive deafferentation.
1. Neural correlates of the permanent deficits in depth perception that occur when extraocular muscle proprioceptive (EMP) afferents are interrupted unilaterally in kittens were investigated by performing extracellular recordings in the primary visual cortex (area 17) in adulthood. Unilateral section of the ophthalmic branch of the trigeminal nerve (V1 nerve) were performed in 11 cats when they were between 5 and 12 weeks of age (uni-V1 group). Electrophysiological results were compared with those obtained in 17 normal adult cats (control group). 2. Binocular interactions were assessed by testing the sensitivity of cortical neurons to dichoptic presentations of moving sine-wave gratings whose interocular positional phase relationship was randomly varied. The amplitude modulation between the minimum and the maximum binocular responses defined the dynamic range. The degree of binocular suppression or facilitation was assessed by comparing these binocular response limits with the optimal monocular responses evoked through either eye at the best spatial frequency. The variability of both monocular and binocular responses was estimated by using the variation coefficient. 3. In uni-V1 cats, both the dynamic range and the degree of binocular suppression were significantly less pronounced than in controls, whereas binocular facilitation was not affected. The variability of the binocular responses was significantly increased, unlike monocular responses, whose variability was similar to control values. 4. From Fourier analysis of the poststimulus time histograms, two clear-cut categories of cells emerged that were differentially affected in the uni-V1 group. The "modulated" cells showed significantly less binocular suppression than in controls, and the "unmodulated" cells had binocular responses that were significantly more variable than in controls. Results from "simple" cells were similar to those of modulated cells, and results from "complex" cells were similar to those of unmodulated cells. However, in the unmodulated population, which was composed of both simple and complex cells, it was shown that the increase of variability was due to that of complex cells. 5. A nonparametric statistical test was applied on the interocular phase shift tuning curves to determine the minimum stimulus change necessary to elicit a significant change in the neural response. Two categories of cells were determined: the "discriminative" cells (80% in controls but 45% in uni-V1 cats) combined pronounced binocular suppression and dynamic range with relatively low variability. The reverse was true in the case of "nondiscriminative" cells (20% in controls and 55% in uni-V1 cats). 6. In uni-V1 cats, about half of the cells were monocularly activated.(ABSTRACT TRUNCATED AT 400 WORDS)
Afferent Pathways↗
[Cortical modulations of the fine temporal structures of impulse trains in the dorsal lateral geniculate body in cats].
In response to a visual stimulation, "replicated triplets" of impulses may appear in many spike trains recorded from the cat dorsal lateral geniculate nucleus (dLGN). The number and the temporal structure of these triplets depend upon the general organization of the geniculate impulse trains. In this study, we show that a pharmacological blockade of the corticothalamic activity, obtained through microinjection of GABA into area 17, affects the replicated triplet production and leads to an increase in the dispersal of their structure. These results suggest that the corticothalamic pathway closely influences the fine temporal organization of the geniculate messages.
Animals↗
[Prenatal diagnosis of neuroblastoma].
One of the prognostic factors for neuroblastoma is age at the time of diagnosis: neuroblastoma detected prenatally or in the first year of live have a more favorable outcome. Antenatal diagnosis is essential early management. Knowledge of local tumor extent is invaluable in determining the appropriate treatment, and MR imaging has proved to be the most useful procedure in this regard.
Female↗
[Pelvimetry by digitalized radiography].
We studied the ability of digital radiographs generated on a computed tomography scanner to replace conventional pelvimetry. Two digital radiograph's and one CT section permit us to measure the maternal pelvis. The anteroposterior digital radiograph allows measurement of the maximum transverse and median transverse diameters of the pelvic inlet. These two distances are corrected for magnification after reference to the lateral digital radiograph and to a graph determined owing to a phantom. The anteroposterior digital radiograph also permits to perform a CT section passing through the ischial spines with direct measurement of the inter spinous diameter. The lateral digital radiograph gives us the true values for the anteroposterior diameter of the pelvic inlet, the low sagittal diameter, the cord and the rise of the sacrum. The dosimetry studies demonstrated that maternal skin doses and fetal gonad doses were very low. Pelvimetry using digital radiography is a simple and rapid to perform procedure which offers the advantage of low radiation exposure to both fetus and mother and a high accuracy of measurement.
Female↗
[Perceptual deficits in the cat deprived of visual experience: psychometric functions established by the conditioned suppression method].
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Animals↗
Vestibular dysfunction in occupational chronic solvent intoxication.
Neurotoxic volatile organic solvents used by house and car painters may lead to professional toxic encephalopathy after several years of exposure. The symptoms are memory impairment, fatigue, personality changes, headache and dizziness. Vestibular dysfunction was found in 55% of 113 painters examined, mainly in the form of reduced caloric vestibular reactions. No correlation between vestibular dysfunction and the duration of exposure, cerebral atrophy or intellectual impairment could be demonstrated. Vestibular examination may be helpful in detecting early changes in exposed persons and in determining more accurate safety limits for harmful chemicals.
Adult↗
Influence of renal nerves on renin secretion in the conscious dog.
In order to evaluate the influence of renal nerves on renin secretion during changes in blood volume, we studied the mean arterial blood pressure (MAP) and the renal venous plasma renin activity (PRA) in 6 conscious dogs having one intact and one denervated kidney. After a passive head-up tilt PRA increased significantly in the vein of the intact kidney while it remained stable in the denervated one. The intravenous injection of Furosemide (3 mg/kg) induced a rapid elevation of PRA in both renal veins. The kinetics of the variations of renin secretion were similar in the two kidneys, but its magnitude was significantly lower in the denervated side. After a slow hemorrhage of 2, 4 and 6 ml/kg, MAP was unchanged and PRA increased in both renal veins but in a significantly lower degree in the denervated side. When blood loss reached 8 ml/kg, MAP decreased and PRA increased identically in the two renal veins. It was concluded that, in conscious dogs, the renal nerves could participate in the rapid adaptations of renin secretion during small changes in the circulating blood volume.
Animals↗
[Neuroleptic analgesia in the management of labor].
Neuroleptic analgesia, which is used for the major part of the conduct of labour, has the advantage of abolishing the pain of uterine contractions without altering the mother's state of consciousness. A study of the effects of droperidol together with phenoperidine on the mother and the child has been carried out. Clinical results, the parameters of the intra-uterine pressure curves and the fetal heart rates as well as of the acid base balance and the pO2 of the mother and infant during dilatation of the cervix and the two first hours of life have been monitored. The conclusion is that neuroleptic analgesia does not cause neonatal depression and can be used as a method for conducting labour so long as very strict monitoring conditions are applied.
Acid-Base Equilibrium↗
Effects of right atrial stretch on plasma renin activity.
In anaesthetized dog, right atrial stretch leads in the first five minutes to a decrease in plasma renin activity, when measured in inferior vena cava just above the renal veins. Bilateral cervical vagotomy increases plasma renin activity. After vagotomy, atrial stretch no longer has any effect on plasma renin activity. The results support the hypothesis of a control of renin secretion originating from atrial volume receptors.
Animals↗
[Primary management of labor using neuroleptic analgesia].
Within the limits granted, neuroleptanalgesia constitutes a very interesting technique in the major part of management of labour. In particular it has the advantage of preserving maternal consciousness. On the other hand, it allows analgesia of rather long duration, which renders early management of labour possible while still respecting its physiology. The institution of this technique demands the presence at the parturients bedside, not only of the obstetrician and the medwife but also that of a qualified anesthetist. As in all cases of major management of labour it engages the responsability of the obstetrical team which undertakes it and this is even more so, the earlier it is started. To us its indications seem comparable with those of Gamma OH: the early management of labour however has the advantage over the latter of preserving maternal consciouness. Moreover it proved to be particularly interesting in the management of breech presentations. But if its properties are an advantage in the indications which we have just mentioned, they can constitute an invonvenience and restrain its use under different circumstances: its slowness of induction, the absence of narcosis which limits the effect on cervical resistance means that one prefers the Toulouse method using pentothal for the management of labour after 7 centimeters of dilatation. In conclusion, it seems important to us to state that neuroleptanalgesia is not the ideal method for management of labour any more than is thiopental or Gamma-OH. Other techniques merit being studied. Their study must obey strict rules in order to specify the risks and therefore the indications and limits. It should cover different fields which are, pharmacology, the objective assessment, by quantitative criteria, of the effects on uterine contraction, on the mother's clinical and biological state as well as that of the fetus in utero, then that of the child in the first hours of live and up to the first years of his development.
Acid-Base Equilibrium↗
Neuronal stereoscopic processing following extraocular proprioception deafferentation.
In adult cats, after section of extraocular muscle proprioceptive (EOMP) afferents during the 'critical period', most cortical area 17 cells loose their ability to discriminate changes in binocular spatial disparity. After unilateral section this loss depends on whether or not cortical cells modulate their responses to the presentation of sinusoidal gratings linearly. For 'modulated cells', this loss is due to a reduction of binocular suppression while for 'unmodulated cells', it is due to a selective increase in the variability of the binocular response. These permanent neural dysfunctions show that balance in EOMP inflow plays a crucial role in cortical processing of binocular depth discrimination.
Animals↗
Nasal absorption of growth hormone in normal subjects: studies with four different formulations.
OBJECTIVE: Current growth hormone (GH) therapy with daily subcutaneous injections results in elevated serum concentrations of GH lasting for several hours, whereas physiologic GH secretion is characterized by a short-duration peak and low basal concentrations. A closer imitation of this pattern might be achieved by administering GH nasally. We studied the effect on the absorption of nasally administered human GH of increasing concentrations of the enhancer didecanoyl-L-alpha-phosphatidylcholine (DDPC). DESIGN: Four formulations of nasal GH containing the enhancer DDPC in the relative concentrations 0, 4, 8, and 16% w/w were administered in random order. SETTING: Participants were admitted to the hospital during the four study periods. INTERVENTIONS: On four occasions the subjects received GH 6 IU (2 mg) in each nostril. Blood was sampled frequently for four hours. Anterior rhinoscopy was performed at 0 and 4 h. During the study the subjects completed a questionnaire to record nasal symptoms. PATIENTS: Sixteen healthy subjects were examined at 0800 h after an overnight fast. MAIN OUTCOME MEASURES: Bioavailability of a nasal preparation of human GH: area under the curve (AUC), the maximum concentration (Cmax), and the time to reach maximum concentration (tmax). Scores for each nasal symptom were recorded as were the total scores. RESULTS: AUC, Cmax, and tmax were not significantly affected by increasing the DDPC concentration from 0 to 4 percent or from 8 to 16 percent. AUC and Cmax, however, increased significantly when the concentration of DDPC was changed from 4 to 8 percent. Mean (+/- SD) AUC (microgram.h/L) increased from 20.51 +/- 10.53 (4 percent) to 46.14 +/- 34.59 (8 percent), (p < 0.005). Mean (+/- SD) of Cmax (microgram/L) increased from 11.11 +/- 5.02 (4 percent) to 28.22 +/- 20.85 (8 percent), (p = 0.002). Mean (+/- SD) of tmax (min) was not significantly different on the four occasions (range 40.6 +/- 36.4 to 61.0 +/- 45.2 min, p = 0.13). The symptom scores (range 17.56-21.5, maximum 360) were not significantly different (p = 0.59). CONCLUSIONS: Increasing the relative concentration of the enhancer DDPC increases the absorption of nasally administered GH.
Absorption↗
[Value of the determination of fetal blood pH in acute fetal distress].
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Female↗