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Biomedical subjects

J Chazal

Publications and source records attributed to J Chazal.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Mechanics of the characteristic geometry of the human spine undergoing vertical pressure].

Since MAGENDIE in 1816, it has been a common assertion in books of Anatomie that curves of the spine increase its strength. This increase in strength has been estimated by a formula attributed to EULER: R = nc2 + 1 in which R is the strength and nc2 stands for the square of the number of curves. Applying the actual law of Euler on the strength of beams submitted to a vertical effort, the authors conclude that strength is increased by about 30% and not multiplied by 10, 16 or even 17 as is often falsely written.

Biomechanical Phenomena↗
PubMed1989

[Ventricular subarachnoidal hydrocephalus of arachnoid villi origin].

In 102 infants (0.5 to 22 months), the C.T. scan performed for various neurological symptoms, was systematically reviewed with analysis of ventricular size, pericerebral space and interhemispheric fissure. In 70% of the cases, an increase of the intracranial volume of C.S.F. was noted, with a good correlation between the ventricular and pericerebral volume. The authors discuss the pathophysiological mechanism of this condition an evoke the possibility of an idiopathic disturbance of the C.S.F. reabsorption. In two cases, suffering from severe axial hypotonus, this fact was explored by four methods: continuous monitoring of intracranial pressure, intraventricular infusion test, isotopic cisternography through ventricular injection and venous phase of angiography. From these investigations showing no venous anomaly, and because of the lack of any pathological event able to induce a C.S.F. obstruction, we suggest a delay in the maturation of arachnoïd villi (normally ended at 18 months) to explain this condition.

Arachnoid↗
PubMed1987

[Congenital stenosis of the aqueduct of Sylvius transmitted in an autosomal recessive mode (5 cases in 2 families)].

The authors report 5 cases of congenital hydrocephalus due to isolated stenosis of the aqueduct of Sylvius. In the first three cases (2 brothers and 1 sister) ventriculograms showed apparent obstruction of the aqueduct. A valve shunting was necessary at 1 month of age in cases 1 and 2, at 3 years of age in case 3. In cases 4 and 5 (1 brother and 1 sister) ultrasonic prenatal diagnosis showed ventriculomegaly and pregnancies were interrupted respectively at 31 and 28 weeks of gestational age. The pedigree of the families suggests that the inheritance of this abnormality is autosomal recessive. Such an inheritance is very unusual and confirms the difficulty of genetic counseling facing the first occurrence of hydrocephalus with stenosis of the aqueduct of Sylvius in a family. The prenatal diagnosis is based on fetal ultrasonic examination and may be obtained late in the pregnancy leading to therapeutic and ethical tricky decisions.

Abortion, Therapeutic↗
PubMed1986

Transfer kinetics of pefloxacin into cerebro-spinal fluid after one hour i.v. infusion of 400 mg in man.

Nine subjects (5 women) aged between 17-66 years, with hydrocephalus were studied. An external ventricular drain was introduced for diagnostic purposes. Cerebro-spinal fluid (CSF) and plasma samples were obtained at suitable intervals after 1 h infusion of 400 mg pefloxacin. In plasma, pefloxacin Cmax was 8.54 +/- 1.53 (mean +/- S.E.M.) mg/l, at the end of infusion, whereas N-desmethyl pefloxacin concentration was 0.17 +/- 0.03 mg/l. The metabolite accounted for only 2% of plasma levels of pefloxacin. In CSF, pefloxacin Cmax was 2.97 +/- 0.32 mg/l, 5-6 h after the start of infusion, whereas N-desmethyl pefloxacin Cmax varied between 0.1-0.2 mg/l. Apart from the 1 h sample, the CSF/plasma ratio of pefloxacin was 60% which is similar to the unbound fraction of pefloxacin in plasma. The apparent half-life (T1/2) of transfer of pefloxacin from plasma to CSF was 1.26 +/- 0.18 h, assuming a first order process, while the apparent elimination T1/2 in CSF was 13.40 +/- 1.76 h, which is similar to the elimination T1/2 found previously in plasma, thus accumulation of pefloxacin in CSF is unlikely. With the present dosage regimen, CSF quickly attains therapeutic levels of pefloxacin.

Adolescent↗
PubMed1986

[Study of the innervation of the spinal ligaments at the lumbar level].

The authors studied the innervation of the human lumbar spinal ligaments on cadaver or surgical specimens. In the ligaments annexed to the neural arch and in the posterior longitudinal ligament were found free-ending fibers and amyelinic perivascular fibers. In the anterior longitudinal ligament, coexisting with perivascular fibers were found encapsulated corpuscular formations on the ventrolateral aspect of the junction between the intervertebral disc and vertebral body. These findings comfort the role of the anterior longitudinal ligament in proprioception essential both in static and dynamic function of the spine.

Humans↗
PubMed1986

[Prospective trial of treating aneurysmal meningeal hemorrhage by delayed operation under cover of antifibrinolytic therapy].

Seventy patients with subarachnoid haemorrhage due to ruptured intracranial aneurysms were managed by delayed intervention (third week) along with the prescription of antifibrinolytic drugs (tranexamic acid 6 g/daily). During the pre-operative period, 41 patients stayed in the same clinical status as on admission or improved, whereas 29 deteriorated due to rebleeding (4 cases), vasospasm (18 cases), large hematoma (4 cases), hydrocephalus (2 cases) and postarteriographic accident (1 case). Clipping the aneurysm was finally achieved in 42 patients only; with 3 deaths, 3 severe sequellae, 8 light handicaps, and 28 patients considered as cured with returning to previous occupations. As far as the whole series is concerned, these results yield a 38.5% rate of mortality, 20% morbidity, and 41.5% recovery. It is concluded that 1) Tranexamic acid was effective in reducing the risk or rebleeding, 2) Third week delayed intervention associated with this drug significantly reduced the operative mortality, but probably favoured vasospasm, and finally had no beneficial effect on the overall results concerning the entire series of patients.

Adult↗
PubMed1985

Dilatation of the subarachnoid pericerebral space and absorption of cerebrospinal fluid in the infant.

The authors investigated intracranial pressure, resistance to cerebrospinal fluid (CSF) absorption following ventricular infusion and radiopharmaceutical absorption of radionuclide injected into the ventricles in two infants with dilatation of the subarachnoid pericerebral space. The results of this study showed an increased resistance to CSF absorption. Intraspinal CSF absorption was seen to predominate, as shown by isotopic cisternography.

Cerebrospinal Fluid↗
PubMed1985

Biomechanical properties of spinal ligaments and a histological study of the supraspinal ligament in traction.

This paper reports the results of a biomechanical study of 43 human spinal ligaments from fresh cadavers and living subjects. Tensile tests were performed with an original testing machine. The tension load and relaxation were applied at the same constant slow rate (1 mm min-1) on entire ligaments. In order to avoid ligament injuries, fixation in the apparatus was on the bone held in clamps specifically designed for each bone, never the ligament itself or its bony attachments. All the load-deformation curves had a sigmoid shape and during load-unload cycles ligaments exhibited elastic properties. This was particularly evident for the ligamentum flavum. The intertransverse posterior longitudinal ligament and the ligamentum flavum were the most resistant. The elongation-tension curve pattern may be explained by the microscopic architectural change that was studied in supraspinous ligament.

Adult↗
PubMed1985

[Stereotaxic biopsies (SB) of intracranial neoplasms. Considerations apropos of 3,052 cases].

On May 12th 1984 a meeting on stereotactic biopsies of intraencephalic lesions has been held in Marseilles. All French Neurosurgeons and Neuropathologists involved with this technique were present. This report presents, in one hand, the result of an investigation on 3 052 BS and, in the other hand, the synthesis of discussions held on the limits and dangers of the BS, morphology of the biopsy instrument, means of the definition of the target and the microscopic histologic technics and results.

Biopsy, Needle↗
PubMed1984

[Plateau wave, unexpected cause of anoxo-ischemic syncope. Reflections on the pathogenesis of the plateau wave apropos of a case].

The case of a 56 year old female suffering from a carcinomatous meningitis with recurrent attacks of unconciousness is presented. The ischemic nature of the attacks was substantiated through a simultaneous recording of ICP, systemic arterial blood pressure, and EEG. Every syncope was clearly accompanied by 1) a typical ICP plateau-wave, 2) a systemic blood pressure wave of lower amplitude, 3) a considerable correlative diminution of the cerebral perfusion pressure and 4) a slowing down of the EEG. These phenomenons could be provoked by intraventricular injections of a few milliliters of artificial CSF, whereas a ventriculo-peritoneal shunting made them disappeared. The role played by the disturbances of the CSF flow in the production of the plateau waves is discussed.

Blood Pressure↗
PubMed1984

[X-ray computed tomography of intracranial fluid cavities in the infant (ventricles, the interhemispheric fissure and pericerebral spaces)].

The brain of 102 infants with an age range of 0,5-22 months was examined with computed tomography (C.T.). The main indications for C.T. investigations were psychomotor retardation or seizures. There were 70 infants with an increase of the volume of intracranial cerebrospinal fluid characterized by -a pericerebral effusion with a thickness from 1-14 mm -a dilatation of interhemispheric fissure -and most frequently an internal hydrocephalus. This phenomenon and his spontaneous remission suggested, that if arachnoïd will are observed in new-born infants, they increased in complexity with normal function as development proceeded.

Brain↗
PubMed1984

[Talo-calcaneal continuity. Myth or reality?].

On the basis of two separate biomechanical studies of talus and calcaneus, the authors show: the absolute continuity of the trabecular structure of these bones, the mechanical behaviour characterised as "fragile" for the talus and "intermediate" for the calcaneus, superficial strains underload: by photoelastic studies, they are show to be in reversed phases both on their lateral and medial sides. Authors conclude that these two bones act together as sectional across which collect dispach and absorb transmitted forces during gate.

Adult↗
PubMed1984

[Anatomical study of a human case of total celosomia].

The authors studied a human specimen delivered at 36 gestational weeks and presenting with a caelosomia. The various abnormalities could be classified as: superior caelosomia: ectocardia, diaphragmatic hernia; middle caelosomia: liver outside the abdominal cavity, mesenterium commune O, meso-hepato-cave; inferior caelosomia: cloacal extrophia. In addition to the forementioned abnormalities, a lumbosacral meningocele and multicystic kidneys were found. All these abnormalities are exceptionally found all together in one human specimen and this monster might be classified in the total caelosomia group.

Abdomen↗