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Biomedical subjects

J M Fuentes

Publications and source records attributed to J M Fuentes.

At least 37 records · Page 2Linked to original sources
PubMed1992

Lumbar posterior marginal node (LPMN) in adults. Report of fifteen cases.

This report concerns 15 adults (nine men and six women) who experienced lumbar and sciatic pain associated with an unusual defect of the edges of the vertebral bodies together with a small bony ridge protruding into the spinal canal. This lesion was well demonstrated by computed tomography and easily differentiated from the posterior longitudinal ligament or herniated disc calcifications, as well as from posterior degenerative ridge osteophytes. This lesion looked like the so-called lumbar posterior marginal node. First described in adolescents, this entity was considered as a traumatic fracture of the posterior ring apophysis. Recently, identical cases were noted in young adults in the absence of previous trauma, which were a particular type of marginal cartilaginous node. In the cases reported here, the computed tomographic scans suggested several mechanisms of formation of the vertebral lesion: a variant of marginal cartilaginous nodes; traumatic avulsion; avulsion related to disc herniation; and fusion of the avulsed bony fragment with the vertebral body.

Adult↗
PubMed1991

Physico-chemical properties of hepatocyte plasma-membrane-bound arginase.

Rat liver plasma-membrane-bound arginase was investigated in order to obtain data regarding its physico-chemical properties. Arginase bound to plasma membrane presented a specific activity of 0.74 +/- 0.09 IU/mg for the fully-activated enzyme, the pH of maximum activity being 9.8. Maximum stability was recorded at two pH values, 7 and 10.5 respectively. Mn2+ activated the enzyme, while Cu2+ and Zn2+, and to a lesser extend Co2+, showed a strong inhibitory effect. Ca2+ and Mg2+ had no effect at the concentrations assayed. The influence of temperature was studied in the presence and in the absence of Mn2+. The enzyme was stable up to 65 degrees C in both cases. Membrane- bound arginase showed an activation energy of 11.5 +/- 1.4 Kcal/mol between 20 and 40 degrees C, and 13.3 +/- 2.5 Kcal/mol between 40 and 60 degrees C. The Q10 for the same temperature ranges were 1.78 and 1.9 respectively. The membrane-bound enzyme presented two different Michaelis constants, one with high affinity (2.05 +/- 0.73 mM) and the other with low affinity for arginine (130 +/- 27.2 mM). Solubilized arginase showed very similar values. Among all the structural analogous assayed, only L-canavanine proved to be substrate for arginase, with and L-arginine/L-canavanine hydrolysis ratio of 5.8 +/- 0.28. No reactivity was found between plasma-membrane-bound arginase and anti-rat liver arginase antibodies raised in rabbits.

Animals↗
PubMed1990

[Intraspinal paraganglioma. Apropos of 3 cases with a review of the literature].

The authors present three cases of paraganglioma located in the cauda equina. In all cases pre-operative diagnosis was neurinoma of the cauda equina and only the histology permitted correct identification. All were intradural extramedullary tumors and in two cases the presenting and dominant symptom was low back pain and sciatica. The remaining third case experimented a paraparesis with urinary and fecal incontinence. The follow-up (range of 4 months-4 years) after total excision was uneventful in two cases and showed in the third case with preoperative paraparesis, some persistent urinary incontinence (follow-up: 3 years) with good motor recovery. The light microscopic features were a Zellballen pattern of cells containing argyrophil granules. Electron microscopy was not performed. The most likely theory regarding the embryogenesis of cauda equina paragangliomas is that they arise from pre-existing paraganglia, possibly of the visceral-autonomic group. The prognosis after complete excision appears to be good. The literature is thoroughly reviewed.

Adult↗
PubMed1989

[Pharyngo-esophageal risk of surgery of the cervical spine using an anterior approach].

The authors report six cases of pharyngo-oesophageal damage associated with fractures of the cervical spine treated by osteo-synthesis via the anterior route. These complications, not previously described, may have life threatening (especially mediastinitis) and functional consequences. They discuss the relative responsibility of: the initial trauma, which should be better defined by an initial endoscopic assessment. the surgical approach, the principles of which and its dangers and preventive aspects are discussed, early or late fixation failure justifying careful surveillance of the osteosynthesis material and in certain cases its systematic removal.

Adult↗
PubMed1989

[Strategy of the surgical treatment of primary tumors of the spine].

The surgical treatment of the primary spinal tumors is started after the analysis of the following data: --location of the tumor, --pathological identification after the biopsy examination, --staging of the lesion according to Enneking. In case of benign tumors it is possible to realize: a total resection by morcellement until healthy margins in case of chondroma or osteochondroma, intralesional excision until healthy borders in case of osteoid osteoma, total excision by partial anterior or posterior vertebrectomy (with previously embolization) according to the location (body or neural arch resection) in case of giant cells tumour or aneurysmal bone cyst. In case of malignant tumors, the total resection is an absolute goal when the feasability occurs (total vertebrectomy), in case of chordoma, chondrosarcoma and malignant giant cells tumours; the stabilization surgery is indicated without attempt of total tumor removal because others means are availables and/or accurates (radio and/or chemotherapy) in cases of Ewing's sarcoma, plasmocytoma and lymphoma.

Humans↗
PubMed1989

[Surgery of the craniocervical junction in primary tumors of the spine].

Tumors of the cranio-cervical junction can be surgically approached either anteriorly or posteriorly. The main anterior (transoral, transcervical or lateral) and posterior routes are described. Posterior approach is used for localization on the posterior arch and for anthrodesis. Anterior approach is proposed for extra-dural lesions of the anterior part of C1 and the foramen magnum.

Humans↗
PubMed1989

[Tumor surgery of the thoracolumbar vertebrae (mobile spine)].

Three main techniques can be discussed for surgery of spinal tumor at the thoraco-lumbar level: posterior stabilization, partial vertebrectomy (lamina or body) and total vertebrectomy. Surgical principles to realize these 3 techniques are described according to the tumoral level: upper thoracic (C7-T3), midthoracic (T4-T10), thoraco-lumbar (T11-L2), upper lumbar (L2-L4) and lower lumber (L5-S1).

Humans↗
PubMed1989

[Primary tumors of the spine. A multicenter cooperative study].

This chapter incorporates 206 observations from the different neurosurgery units which replied to the questionnaires on primary tumours of the vertebral column. A homogeneous data bank, analysed and processed using the Excel database, was established by retranscribing each observation into 32 sections. The majority of the sample population (fig. 1) was male and included 42 observations of subjects under the age of 18 years, thereby constituting one of the largest series in this age range. The global histological distribution demonstrates a predominance of malignant tumors in the adult (65%) with no sexual bias. In children, malignant (19 cases) and benign (23 cases) tumours are more homogeneously distributed (fig. 3 and 4). The different histological types encountered are listed in table I in order of frequency. In order to make it easier to read the following tables, the numerical code given to each histological type is indicated in table II. Chordomas (code 14), which most authors classified among the malignant tumours, are situated in a transitional zone between benign tumours (from 1 to 13) and malignant tumours (from 15 to 37) on the various graphs. Histological distribution in adults (fig. 5) demonstrates the existence of two peaks in the malignant tumor zone: the highest peak correspond to the chordomas, the other to solitary myelomas. In children (fig. 6), distribution is different: the benign osteoblastoma and the aneurysmal bone cyst are the most common benign tumors, and the most common malignant tumor observed is Ewing's sarcoma. The different tumor sites along the spinal axis are reported in figures 7, 8, 9, 10 and 11.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

[Technic of the peroperative use of Doppler in neurosurgery].

Intraoperative Doppler exploration during neurosurgery was used during treatment of intracranial aneurysms, arteriovenous malformations (AVM) and cerebral revascularization by extra-intra cranial anastomosis (EICA). It was also employed to study behavior of cortical arteries under different conditions. During treatment of aneurysms, Doppler can show, prior to clipping, whether blood flow through. The flow is regular--spasm of supply artery provokes acceleration of blood rate. After clipping it is possible to evaluate whether artery is still permeable without stenosis or torsion. In AVM, Doppler detects direction of blood. Flow and, in case of intraoperative embolization, confirms good exclusion of angiomatous nidus. Flow rate in cortical arteries was determined to verify reality of operative trauma under automatic retractors used in standard surgery. In EICA, Doppler provides precise data on exact localization of cutaneous incision centered on superficial temporal artery (STA) (longitudinal incision) and identifies its parietal branch. The artery in the cortical vessels with the lowest flow rate can be selected. After EICA it is possible to identify whether the donor artery is under spasm from the proximal clamp and whether or not the anastomosis is patent. When functioning is correct it can be defined whether there exists a preferential direction or a regular laminar distribution in T. In tumoral pathology, Doppler serves to identify arteries enclosed in lesion and therefore whether conservation is essential.

Cerebral Revascularization↗
PubMed1988

[Aneurysmal bone cyst of C5. Complete 2-stage excision].

A case of aneurysmal bone cyst of the fifth cervical vertebra was unusual in that it occurred in a 35 year old man treated initially by radiotherapy (3,800 rads), within 3 years, worsening of clinical and radiologic signs led to a complete two-stage exeresis because of extension of lesion to body and posterior arch of C5. This male patient was 35 years old at diagnosis and 38 at time of surgery (respectively 1.2 and 2.5% of cases in the Hay series and 1.9% in the Ruiter series), this lesion affecting mainly age groups under 20 years. Aneurysmal bone cyst (ABC) constitutes 1.4% of primary bone tumors (Dahlin), and spinal localizations 3% (Biesecker), 14% (Reiter) or 20% (Tillman) of total ABC. The cervical lesion represents 13% (Reiter) or 22% (Hay) of spinal localizations, C5 being affected twice in the 17 cases reported by Ameli, and fills, according to Hay, 3.3% of all spinal column lesions and 15% of cervical lesions. Initial treatment applied in another center was by radiotherapy alone at the dose of 3,800 rads (the recommended dose-level in the literature being 20 to 30 Grays). Neither clinical nor radiologic improvement was reported. The recurrence rate after all types of treatment for ABC was 12.6%, and after radiotherapy alone was 11% in the Hay series, MacCarty reporting only one recurrence among 9 patients treated with irradiation alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Experimental paraplegia].

In this review of spinal cord injury research, the authors have selected contributions including their own research in electrophysiological changes after impact, which in their opinion best represent modern experimental concepts regarding the physiopathological mechanism of spinal cord injuries. The discrepancy between immediate electrophysiological changes and progressive hemorrhagic necrosis of the spinal cord could offer a rational treatment at the acute stage of spinal cord injury.

Animals↗
PubMed1986

[Fracture-separation of the articular process of the lower cervical spine. Its relation to fracture-dislocation in hyperextension].

The authors have seen 13 cases of fracture-separation of the articular processes in the lower cervical spine with horizontal facets. This type of lesion was caused by trauma in hyperextension, compression and rotation. The mechanism appears to be similar to that of dislocations in hyperextension. Four types are defined according to the displacement and the association of disc and ligamentous lesions. Most of the cases were unstable and had to be fixed surgically. Eleven cases were treated in this way, twice by a posterior approach, 6 times by an anterior approach and 3 times by a combined anterior and posterior approach.

Adult↗
PubMed1986

[Panmedullary ependymoma with complete excision in several stages. Apropos of a case].

Treatment of a panmedullary ependymoma involved a three-stage operation with total excision under microscopic control and the use of the Cavitron. The patient, a 22 year old woman, presented with a three-year history, with clinical onset of staged spinal pain and cervicobrachial neuralgia, of spasmodic paraparesis with sensory and sphincter disturbances. The extent of the lesion from C3 to L2 was determined from data from conventional myelography with Iopamiron, a CT scan with intrathecal contrast and nuclear magnetic resonance imaging of sagittal and frontal sections. The tumor, a grade I ependymoma, was treated by three-stage laminectomies (L2-T12, T12-T3, T3-C3), total excision being obtained by ultrasound fragmentation (Cavitron). Gross pathology showed a heterogeneous appearance with two cysts, one capping the tumor from the bulbospinal junction to C3, the other attached to the medullary cone. Hemorrhagic cavities were noted at cervicothoracic region and multiple microcysts in the dorsal expansion. The postoperative course was uneventful with recovery of walking wearing a bivalve acrylic corset, the most disturbing functional complication being the posterior cord syndrome responsible for an ataxia.

Adult↗
PubMed1985

Radiation necrosis of the brain: time of onset and incidence related to total dose and fractionation of radiation.

Clinical deterioration during or after brain irradiation may be due to progression of neoplasm or radiation induced necrosis of the neoplasm and/or of normal brain tissues, or a combination of all. Eight patients with histologically documented radiation induced lesions of the brain are included in this study. The radiation therapy included the fractional schedule, group A, who received 280 to 300 rads daily, to a total dose of 4500 to 5000 rads and weekly exposure did not exceed 900 rads. Group B patients were exposed to 850 rads, daily dose on day 1, 3, 21 and 23 to a total dose of 3400 rads. The incidence of radiation induced lesions of brain was 3.4% in patients group A and 8.7% in group B patients (without statistical significance). The median time of onset of these lesions after completion of radiation therapy was significantly shorter in group B patients (8.5 months) as opposed to group A patients (21 months).

Brain↗
PubMed1985

[Series of 17 cases of giant intracranial aneurysms. Long-term surgical follow-up and hemodynamic effects of arterial occlusions].

The authors report their experience of 17 cases of giant intracranial aneurysms some of them with particular forms and localisations: Giant serpentine aneurysms in 17.6%, carotid cavernous, carotid, Willis Circle and vertebral branches. 8 cases were operated, 2 by direct neck occlusion and 6 others by carotid or vertebral interruption. For the nine non operated cases 5 were in a very bad clinical condition and 4 had refused the operation. Aneurysmal neck occlusion gave uneventful results lasting more than 4 and 10 years. Carotid or vertebral branches occlusion showed 16.6% mortality. In one case, the post operative death happened after 8 days of well tolerated carotid occlusion and in spite of a functional extra-intra-cranial anastomosis. Very good surgical outcome was seen in the other cases for over 3 and 22 years. Arterial occlusion in giant aneurysm surgery can bring multiple complications as in one case iatrogenic aneurysmal formation like in experimental Hassler and Hashimoto's descriptions. Curiously in the same way can be explained the ruptured intra cranial aneurysmal formation in some ischemic cerebral disease like Moyamoya syndrome or Takayashu disease.

Adult↗
PubMed1985

[Osteosynthesis of the low lumbar spine and spondylolisthesis. Modification of the Scholner plate and pedicular screwing].

A modification of Roy Camille's Technic for better screw location into the pedicle of vertebra of the low lumbar column and lumbo-sacral junction is reported. A small 5 millimeters resection of the inferior articular process allows a more cranial drill-hole which is more steadily in the pedicle of the vertebra as confirmed by X rays controls and anatomic specimens. A 10 degree slope to a caudal direction is needed at the L5 level and a 30 degree slope to a caudal direction is required at S1 level. 50 millimeters length screw can be used for adult patients. Some modification of Scholner's plate are proposed in spondylolisthesis surgery.

Bone Plates↗