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Biomedical subjects

G Cheron

Publications and source records attributed to G Cheron.

At least 91 records · Page 5Linked to original sources
PubMed1987

[Treatment of reflex vagal hypertonia in infants. Role of diphemanil (apropos of 50 cases)].

For a period of 20 months, 50 consecutive infants (mean age: 11 months) were given Diphemanil (atropine like synthetic drug) for reflex symptomatic bradycardia of probable vagal origin. Treatment's results were evaluated with the study of oculo-cardiac reflex (OCR) and Holter monitoring performed before and 3 months after the beginning of Diphemanil. If tolerance was generally good, it was not possible to demonstrate the clinical efficacy of the treatment on the whole group. However, assertive success was seen on individual cases. Holter and OCR data improved statistically. The other therapeutical means aiming at warning possible complications of the hypertonic vagal reflex were reviewed: inserting a cardiac pace-maker does not always prevent sudden death; a nodal sinus surgical selective denervation might be justified in certain exceptional cases, because of the severity of the spontaneous evolution or of the resistance to medical treatment.

Bradycardia↗
PubMed1986

Lesions in the cat prepositus complex: effects on the vestibulo-ocular reflex and saccades.

The effects of bilateral electrolytic lesions within and around the prepositus hypoglossi (p.h.) nucleus on horizontal saccades in the dark and on the horizontal sinusoidal vestibulo-ocular reflex (v.o.r.) in the dark were studied. After p.h. lesion, including its rostral part between P 7 and P 8, the v.o.r. showed a phase lead as much as about 90 deg at 0.10 Hz. A significant gain reduction paralleled that phase lead at lower frequencies. A large post-saccadic drift was also observed, the time constant of which ranged from 0.3 to 0.6 s. After p.h. lesion extending from P 8 to P 11 (but sparing the rostral part of the p.h.), no significant gain or phase lead change was observed. Post-saccadic drift was either missing or weak. A bilateral medial vestibular nucleus (m.v.n.) lesion from P 7 to P 11 produced a marked gain decrease, paralleled by a marked phase advance. A post-saccadic drift was observed (tau = 0.6 s). A surgical mid-line lesion from P 7 to P 11 (depth: about 2 mm) was followed by no remarkable change in the gain and in the phase of the v.o.r. No post-saccadic drift was observed after such lesion. It was concluded that (i) both the horizontal v.o.r. integration processing, and the horizontal saccadic integration processing were destroyed when an electrolytic lesion was made 'in the region of' the rostral part of the p.h. nucleus, and that (ii) the posterior four-fifths of the p.h. was the location of neither the horizontal v.o.r. integrator nor the horizontal saccadic integrator.

Animals↗
PubMed1986

Lesions in the cat prepositus complex: effects on the optokinetic system.

The effects of bilateral lesions within and around the prepositus hypoglossi (p.h.) nuclei on the optokinetic system were studied. The pure optokinetic nystagmus (o.k.n.) was evoked by a step of velocity (60 deg/s, 30 s duration) of the surrounding. The visual-vestibular interaction was investigated by measuring the gain and phase of the vestibulo-ocular reflex (v.o.r.) as a function of frequency before and after lesion under three different conditions of testing: basic v.o.r. tested in the dark, v.o.r. tested in the light and v.o.r. suppressed by vision. The tested amplitude was +/- 20 deg. A posterior vermectomy was performed for controls in two cats. A bilateral electrolytic p.h. lesion including the rostral pole of this nucleus was added to the posterior vermectomy in three cats. A lesion similar but sparing the rostral pole of the nucleus was carried out in three other cats. In one cat a bilateral electrolytic lesion of the medial vestibular nuclei (m.v.n.) was combined with a posterior vermectomy. In two cats the medulla was cut on the mid line after a posterior vermectomy. The posterior vermectomy affected neither the optokinetic response nor the visual-vestibular interactions. In cats where p.h. lesion included its rostral pole and in the cat with m.v.n. lesion, all the tested optokinetic effects (step o.k.n., and visual-vestibular interactions) were abolished. In the three cats where p.h. lesion spared its rostral pole, the optokinetic effects were quite normal in one cat, mildly reduced in the second one, and seriously affected but not completely abolished in the third one. The surgical cut of the medulla on the mid line did not dramatically disturb the various optokinetic effects. The most marked deficit was the loss of the optokinetic after-nystagmus (o.k.a.n.). From the comparison of these results with the neuroanatomical data and with the Robinson's model concerning the optokinetic processing, it was suggested that: (a) the rostral p.h. could be the location of the o.k.n. integrator or could be an essential link on the o.k.n. pathway, (b) the posterior four-fifths of the p.h. could not be an essential relay on the o.k.n. pathway, (c) the loss of o.k.a.n. after mid-line lesion could be due to the interruption of the positive feed-back loop formed by the reciprocal inhibitory connexions between the two m.v.n.

Animals↗
PubMed1986

[Congenital hyperparathyroidism. 3 cases].

Hypotonia, neonatal respiratory distress with a chest wall deformity should arouse clinical suspicion to the diagnosis of primary hyperthyroidism. The most common signs at this age are hypercalcaemia, increased alkaline phosphatase, low TRPP and radiological changes especially in the hip. Radio-immunological assay of PTH and plasma concentrations of Vitamin D metabolites are important diagnostic aids but the interpretation of these results should take the clinical and familial context into consideration. Rapid bone structural changes, the resistance of the hypercalcaemia to usual therapeutic measures and the progression to rickets justify urgent surgical treatment. Nearly all cases are due to clear cell hyperplasia.

Alkaline Phosphatase↗
PubMed1986

[Blood pressure from 0 to 18 months. Use of an automatic measurement method].

A prospective study of blood pressure in 251 neonates and infants aged 0 to 18 months was undertaken with an automatic measurement method. Children of black race (n = 33) were taller (p less than 0.05), heavier (p less than 0.025) and older (p less than 0.001) than the rest of the sample, but had lower systolic (SAP) and diastolic arterial pressures (DAP), especially between 9 and 18 months (p less than 0.01). There was no significant difference according to race [North Africans (n = 50), white (n = 143) and the others (n = 25)], or to sex. For the sample (n = 218) of non black children, SAP and DAP increased with age (p less than 0.001), weight (p less than 0.001) and height (p less than 0.001). Percentiles were determined in each age class for SAP and DAP. Mean pressure figures increased from 86.8 mmHg (0-1 month) to 108 mmHg (9-12 months) for SAP and from 52.5 mmHg (0-1 month) to 65.5 mmHg (9-12 months) for DAP.

Age Factors↗
PubMed1985

Effects of applied vibration on triphasic electromyographic patterns in neurologically ballistic head movements.

Vibration of agonist or antagonist muscle tendon produced changes in the triphasic electromyographic pattern of neck muscles; EMG signals were rectified, averaged, and also integrated by planimetry. The triphasic EMG envelopes obtained during fast horizontal head rotation showed unmodified early agonist pulse, the action pulse (PA), under all conditions; increased antagonist pulse, the braking pulse (PB), only with antagonist muscle vibration; and increase of late agonist pulse, the clamping pulse (PC), only with agonist muscle vibration. Vibration experiments can be considered as a model for studying interactions between central and peripheral effects on control of normal movements.

Electromyography↗
PubMed1984

[Chronic septic granulomatosis. Disclosed by hepatic abscesses. Contribution of echography].

Skin infections and lymph node abscesses are the most common manifestations of chronic granulomatous disease (CGD) during the first year of life. Intra-hepatic abscesses occur later on. The case reported concerns a 4 month-old infant, in whom the disease presented initially with liver abscesses. Percutaneous needle aspiration of the liver under ultrasonographic control permitted the isolation of Staphylococcus aureus and allowed partial regression of the abscesses. Surgery was not required.

Granulomatous Disease, Chronic↗
PubMed1984

[Hypophosphatemic rickets in premature infants independent of vitamin D].

The etiology and prevention of rickets in prematures infants are still controversial: insufficient storage or intake in minerals and/or vitamin D, immature vitamin D metabolism, necessitating early vitamin supplementation, for some associated with calcium and phosphate supplementation. The authors report a case of rickets which could be related to an immaturity of the tubular mechanisms of phosphate reabsorption, with a favourable outcome following an increase in calcium and phosphate intake.

Calcium↗
PubMed1983

Spinal and far-field components of human somatosensory evoked potentials to posterior tibial nerve stimulation analysed with oesophageal derivations and non-cephalic reference recording.

Somatosensory evoked potentials (SEPs) were elicited by stimulation of the right posterior tibial nerve at the ankle in 20 experiments on 18 normal adults. A non-cephalic reference on the left knee was used throughout (with triggering of averaging cycles from the ECG), except for recording the peripheral nerve potentials. The responses were recorded along the spine, from oesophageal probes and from the scalp. The peripheral nerve volley propagated at a mean maximum conduction velocity (CV) of 59.2 m/sec served to identify the spinal entry time (mean 19.7 msec) at spinal segments S1-S3, under the D12 spine. This entry time coincided with the onset of the N21 component which was interpreted as the dorsal column volley and considered equivalent to the neck N11 of the median nerve SEP. The large voltage of the spinal response at the D12 spine probably results from summation of N21 with a fixed latency N24 potential that phase reverses at oesophageal recording sites into a P24. The N24-P24 reflects a horizontal dipole in the dorsal horn and is equivalent to the N13-P13 of the neck SEP to median nerve stimulation. Spinal conduction between D12-C7 spines was spuriously overestimated because the true length of the dorsal spinal cord is shorter by about 13% than the distance measured on the skin over the dorsal convexity. This correction should be applied routinely and it leads to a mean maximum spinal CV of 57 m/sec. Several positive far fields with widespread scalp distribution and stationary latencies have been identified. The P17 (over spine and head) reflects the peripheral nerve volley at the upper buttock. The P21 is synchronous with the N21 at the D12 spine and reflects the initial volley in the dorsal column. No far-field equivalent has been found for the N24-P24, due to the horizontal axis of the corresponding dipole. The P26 far field reflects the ascending volley at spinal levels D10-D4. The P31 reflects the initial volley in the medial lemniscus. The P40 at Cz represents the cortical response of the foot projection. Average central CVs were calculated and discussed.

Adult↗