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J M Fuentes

Publications and source records attributed to J M Fuentes.

At least 19 recordsLinked to original sources
PubMed1996

[Anterior and anterolateral surgery of the lower cervical spine (25 years after H. Verbiest). I: Technical bases].

The anterior approach to the cervical spine is currently a worldwide traditional surgical technique used by neurosurgeons or orthopedists in the treatment of traumatic, degenerative or tumoral cervical spinal lesions. Many original rules of these techniques were raised by pioneers as R. Cloward and H. Verbiest, and are still valid. Advances in the surgical armentarium and in bio-materials markedly improved the original technique and subsequently improved the clinical results. The present course was organized for the neurosurgery trainees by the French Speaking Neurosurgical Society, and was helded during the winter meeting in December 1995. The aim of this course is to recall the basic technical principles of the microsurgical anterior cervical approach, and to discuss the main indications of this surgical treatment. Many theoretical points are strengthened by the author's personal experience and comments. Part I presents the different anterior or antero-lateral approaches which any surgeon involved in cervical spine surgery actually needs to know. Secondly, the materials and technical basis needed to achieve an interbody graft or fusion or fixation are described. Lastly, some practical applications are detailed as a microdiscectomy, a medial or lateral cervical spine decompression, and the use of acrylic plastic or prothesis for a cervical vertebral replacement.

Bone Transplantation↗
PubMed1996

[Anterior and antero-lateral surgery of the lower cervical spine (25 years after H. Verbiest). 2: Indications, results, complications)].

The present course on the anterior and antero-lateral surgical approach of the lower cervical spine was organized for the neurosurgery trainees by the French Speaking Neurosurgical Society, and was held during the winter meeting in December 1995. The aim of this course was to recall the basic technical principles of the microsurgical anterior cervical approach, and to discuss the main indications of this surgical treatment. Many theoretical points were strengthened by the author's personal experience and comments. In Part I, the technical bases of the different anterior or antero-lateral approaches were presented (1996, 42 : 105-122). In the present Part II, the main indications of the anterior surgical approach to the cervical disk or the vertebral body are detailed, and the requirement of a bone graft and/or an osteosynthesis are discussed with their consequences on the final results. Secondly, variants of the surgical technics in use in case of cervical spinal instability are commented. Then various approaches to the cervical spinal tumors and to the vertebral artery are detailed and commented. Lastly, general and specific complications of the anterior cervical approach are listed with their rate of occurrence, and their prevention and management are discussed.

Cervical Vertebrae↗
PubMed1994

Kinetics of manganese reconstitution and thiol group exposition in dialyzed rat mammary gland arginase.

1. Rat mammary gland arginase is a metallo-enzyme dependent on Mn2+, which can be only partially substituted by Cd2+. 2. Reconstitution of the activity of dialyzed arginase by manganese is a two-phase process; the second phase is independent of the cation concentration, with a half-time recovery (t1/2) of 10.77 min. 3. The apparent Km for Mn2+ is 280 microM and 10.5 microM for enzyme dialyzed for 24 and 72 hr, respectively. 4. Treatment with 5 mM EDTA at pH 6 totally inhibits enzyme activity, which is reconstituted by Mn2+. 5. Results obtained with iodoacetamide treatment suggest the existence of sulphydryl groups accessible only when the enzyme is dialyzed.

Animals↗
PubMed1994

Immunological identity of the two different molecular mass constitutive subunits of liver arginase.

A detailed understanding of the regulatory mechanisms of arginase in the cell will depend on the clarification of the origin of the two different molecular mass subunits and on the arrangements of them to constitute the native enzyme. Here, we show the immunological recognition of the 39.5 and 37.0 kDa subunits of arginase by antibodies against both subunits. We also find that the subunit stoichiometry (39.5 kDa: 37.0 kDa) present in purified arginase preparations as well as in fresh isolated microsomes and cytoplasm corresponds to 3:1, indicating high prevalence of a constant arrangement of the constitutive subunits of arginase. These findings represent evidence for a limited posttranscriptional or posttranslational modification of only a fraction of the synthesized arginase in liver.

Animals↗
PubMed1993

Parallel induction of nitric oxide and glucose-6-phosphate dehydrogenase in activated bone marrow derived macrophages.

The production of nitric oxide (NO.) and the induction of glucose-6-phosphate dehydrogenase by lipopolysaccharides (LPS) from different sources was studied in bone marrow derived macrophages (BMM phi). NO. production was found to be linked to the induction of glucose-6-phosphate dehydrogenase, suggesting the possible involvement of this enzyme in the cytotoxic mechanism resulting from the release of NO. by activated macrophages.

Animals↗
PubMed1992

Unfolding and trypsin inactivation studies reveal a conformation drift of glucose-6-phosphate dehydrogenase upon binding of NADP.

Binding of NADP to glucose-6-phosphate dehydrogenase (G6PD) from Dicentrarchus labrax liver has stabilized its native structure against thermal inactivation, guanidine hydrochloride unfolding and inactivation by tryptic digestion. The time-course of G6PD inactivation by guanidine hydrochloride in the presence of NADP has provided experimental evidence in favor of a conformational drift upon NADP binding to the bass enzyme. Based on the inactivation patterns obtained when the enzyme was treated with guanidine hydrochloride and trypsin, it is proposed that the enzyme conformation induced upon NADP binding is in slow equilibrium with the conformation stabilized in the absence of NADP. FPLC studies have shown that micromolar concentrations of NADP induced oligomerization of G6PD. In addition, the different K0.5 values of NADP binding to the enzyme, ranging from 1-2 microM (from trypsin inactivation) to 90 microM (from titration of the intrinsic fluorescence), suggest a step-wise binding of NADP to the oligomer, with negative cooperativity in the saturation process.

Animals↗
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↗