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Biomedical subjects

E de Oliveira

Publications and source records attributed to E de Oliveira.

At least 19 recordsLinked to original sources
PubMed2005

Microsurgical considerations of the anterior spinal and the anterior-ventral spinal arteries.

BACKGROUND: There are few data describing the microanatomy of the anterior-ventral spinal (AVSA) and anterior spinal arteries (ASA) and discussing their clinical and surgical implications. We describe the anatomical features of this arterial complex, and highlight their use when planning and performing surgical approaches to lesions involving the ventral aspect of the medulla and the foramen magnum. METHOD: The microsurgical anatomy and branching pattern of the AVSA and the ASA from fifty human cadaver brain stems is described using a surgical microscope. RESULTS: We found one anterior-ventral spinal artery at each side in 30 of the brain stems (60%). The ASA was a direct branch emerging from the left vertebral artery (VA) in 15 (30%), from the right VA in 4 (8%), and from the basilar artery (BA) in one brain stem (2%). The previously described as "typical pattern" of the junction of the AVS arteries from both sides, was observed only in 9 brain stems (18%). The anterior communicating spinal artery (ACoSA) was observed in 15 brain stems (30%). Also multiple ACoS arteries were described in one brain stem. Both, the AVSA and the ASA were observed to send long circumferential branches that supplied irrigation to the olive in 42 (84%) brain stems. CONCLUSIONS: This anatomical study gives important information for a better understanding of the clinical picture of ischemic lesions of the brain stem, such as the medial medullary syndrome, and highlights the remarkable role of the AVSA and ASA as anatomical landmarks during the surgical approaches to lesions involving the ventral aspect of the medulla and the foramen magnum.

Basilar Artery↗
PubMed2003

Clinical and histopathological changes of the nasal mucosa induced by occupational exposure to sulphuric acid mists.

AIMS: To assess potential alterations of the nasal mucosa by clinical and histopathological evaluation of workers exposed to sulphuric acid mists at anodising plants, correlating the findings with duration of exposure and sulphuric acid concentrations in the air, and comparing them with a control group. METHODS: Fifty two workers from five plants underwent a clinical evaluation (standard questionnaire, clinical, and ear, nose, and throat examination including nasal endoscopy). For the histopathological study, 20 of the 52 subjects (study group) were randomly selected, as well as 11 unexposed subjects (control group), matched by sex, age, and smoking habits. Nasal biopsy specimens were obtained from the anterior septum mucosa and the anterior curvature of the middle turbinate in each individual. A total of 56 nasal mucosa specimens (37 in the study group and 19 in the control group) were evaluated with regard to normal respiratory epithelium or metaplastic epithelium, atypia or dysplasia, and alterations of the lamina propria. RESULTS: The histopathological study revealed squamous metaplasia in 29 (79%) and atypia in 13 (35%) of the 37 study group samples. No association was found between exposure duration and the clinical and histopathological variables, but a significant association was found between sulphuric acid concentrations higher than 200 micro g/m(3) and pale mucosal patches and ulcerations in the exposed subjects. Logistic regression analysis showed that the exposed subjects had a fivefold risk of developing atypia compared with the unexposed subjects. CONCLUSIONS: Workers exposed to sulphuric acid mists presented with a high incidence of nasal symptoms, and macroscopic and microscopic changes of the nasal mucosa, including squamous atypia and dysplasia. The risk for these histopthological lesions increased with higher sulphuric acid concentrations in the air, revealing an exposure-response relation.

Adult↗
PubMed2001

Life cycle of the tick Ixodes uriae in penguin colonies: relationships with host breeding activity.

A survey of the temporal pattern of population structure and feeding activity of the seabird tick Ixodes uriae was conducted for the first time in two host species colonies: King penguin (Aptenodytes patagonicus halli) and Macaroni penguin (Eudyptes chrysolophus chrysolophus). The life cycle of the tick was investigated over 3 years in a King penguin colony and 2 years in a Macaroni penguin colony at Possession Island (Crozet Archipelago). There was a marked seasonal feeding activity pattern of ticks in both host species, connected with the presence of birds during the breeding season. Although the King penguin colonies were occupied throughout the year by birds, the favourable period for engorgement was limited to 3.5-4.5 months, and almost all the ticks overwintered in the unengorged state. Consequently, I. uriae probably completed its life cycle over 3 years in King penguin colonies. In contrast, this life cycle could be shortened to 2 years in Macaroni penguin colonies, as a result of a different timetable of the presence of birds for breeding and moulting. The relationships between such plasticity and the host behaviour and subantarctic climatic conditions are discussed.

Animals↗
PubMed2001

Conformationally restricted PACAP27 analogues incorporating type II/II' IBTM beta-turn mimetics. Synthesis, NMR structure determination, and binding affinity.

To probe the importance of a proposed beta-turn within residues S9-R12 of PACAP for recognition by VIP/PACAP receptors, compounds 1 and 2, two conformationally restricted analogues of PACAP27 incorporating respectively (S)- or (R)-IBTM as type II or II' beta-turn dipeptide mimetic at the Y10-S11 position, were synthesized. According to 1H NMR conformational analyses in aqueous solution and 30% TFE, both PACAP27 and the [S-IBTM(10,11)]PACAP27 analogue 1 adopt similar ordered structures. PACAP27 shows an N-terminal disordered region (residues H1-F6) and an alpha-helical conformation within segment T7-L27. For residues S9-R12, our data seem more compatible with a segment of the alpha-helix than with the beta-turn previously proposed for this fragment. In compound 1 the alpha-helix, also spanning T7-L27 residues, appears slightly distorted at the N-terminus relative to the native peptide. Although this distortion could lead to the marked decrease in binding affinity of this compound at the VIP/PACAP receptors, the lack of the Y10 side chain in analogues 1 and 2 could also significantly affect the binding of these compounds.

Amino Acid Sequence↗
PubMed2001

[Study of mineral content of natural or fruits yogurts commercialized in São Paulo, Brazil].

The contents of the macrominerals Na, K, Ca, Mg, and P and the microminerals Fe, Zn, Cu, Mn, Sn and Ni, present in 44 samples of natural or fruits yogurts, of 9 different brands, available in the commerce of São Paulo State, Brazil, were evaluated. Acid digestion assisted by microwave and the determination of the elements by inductively coupled argon plasma atomic emission spectrometry (ICP-OES) were employed. The results showed that the yogurts are good sources of Ca, P and K, reasonable sources of Na, Mg and Fe, and poor sources of Zn and Cu. The multivariate analysis showed non-significant differences among the brands and the flavors studied.

Brazil↗
PubMed2000

The pretemporal transcavernous approach to the interpeduncular and prepontine cisterns: microsurgical anatomy and technique application.

OBJECTIVE: To illustrate in a stepwise fashion the microsurgical anatomy of the transcavernous approach to the interpeduncular and prepontine cisterns and to discuss our initial results with 15 basilar tip aneurysms managed through that approach. METHODS: Using 10 embalmed cadaveric heads perfused with colored silicon, we performed bilateral stepwise dissections of the transcavernous approach via an orbitozygomatic pretemporal craniotomy. Measurements of the exposure of the basilar artery obtained along the dorsum sellae and upper clivus were taken. Our clinical data were derived from a series of 15 patients with large basilar tip aneurysms treated surgically via the transcavernous approach between 1997 and 1999. Indications for surgery were based on the size of the aneurysm (all were large) and its position in relation to the dorsum sellae (eight were more than 5 mm below the level of the dorsum sellae). RESULTS: Good exposure of the neurovascular structures of the interpeduncular and prepontine cisterns (namely, the basilar artery) was obtained in all cases as compared with other well-established approaches to the area. All patients in our surgical series did well except that all incurred an expected third nerve palsy, caused by surgical manipulation, which resolved over the course of 2 weeks to 3 months. CONCLUSION: Although technically difficult, the transcavernous approach provides better exposure of the interpeduncular and prepontine cisterns relative to that afforded by other, more conventional approaches. The satisfactory results obtained in our preliminary series of patients greatly support the use of this approach for complex basilar tip aneurysms.

Angiography, Digital Subtraction↗
PubMed2000

Persistent trigeminal artery: a unique anatomic specimen--analysis and therapeutic implications.

OBJECTIVE: Persistent primitive carotid-basilar artery anastomoses are uncommon, and are usually seen on an angiogram or discovered at autopsy. The most frequent type of anastomosis is the persistent trigeminal artery. METHODS: A single case of a medial variation of the persistent trigeminal artery, as seen in a well-preserved human adult anatomic specimen injected with red latex, is presented, and the anatomy of this uncommon anastomosis is discussed. RESULTS: This specimen is unique in its clear preservation of the artery, which arises from the medial portion of the right intracavernous carotid artery and gives rise to two branches, the inferior hypophyseal artery and the dorsal meningeal artery to the clivus. CONCLUSION: A new variation of the persistent trigeminal artery is described, which is important to support the possibility that more than one variety of carotid-basilar anastomosis exists in this region.

Basilar Artery↗
PubMed1999

Microsurgical anatomy of the temporal lobe: part 1: mesial temporal lobe anatomy and its vascular relationships as applied to amygdalohippocampectomy.

OBJECTIVE: We review the anatomy of the mesial temporal lobe region, establishing the relationships among the intraventricular, extraventricular, and surrounding vascular structures and their angiographic characterization. We also demonstrate the clinical application of these anatomic landmarks in an anatomic temporal lobectomy plus amygdalohippocampectomy. METHODS: Fifty-two adult cadaveric hemispheres and 12 adult cadaveric heads were studied, using a magnification ranging from 3x to 40x, after perfusion of the arteries and veins with colored latex. RESULTS: The intraventricular elements are the hippocampus, fimbria, amygdala, and choroidal fissure; the extraventricular elements are the uncus and parahippocampal and dentate gyri. The uncus has an anterior segment, an apex, and a posterior segment that has an inferior and a posteromedial surface; the uncus is related medially to cisternal elements and laterally to intraventricular elements. The anterior segment is related to the proximal sylvian fissure, internal carotid artery, proximal M1 segment of the middle cerebral artery, proximal cisternal anterior choroidal artery, and amygdala. The apex is related to the oculomotor nerve, uncal recess, and amygdala; the posteromedial surface is related to the P2A segment of the posterior cerebral artery inferiorly, to the distal cisternal anterior choroidal artery superiorly, and to the head of the hippocampus and amygdala intraventricularly. The choroidal fissure is located between the thalamus and fimbria; it begins at the inferior choroidal point behind the head of the hippocampus and constitutes the medial wall of the posterior two-thirds of the temporal horn. CONCLUSION: Not only is the knowledge of these relations useful to angiographically characterize the mesial temporal region, but it has also proven to be of extreme value during microsurgeries involving this region.

Adult↗
PubMed1998

Comprehensive management of arteriovenous malformations.

The treatment of arteriovenous malformations depends on the efforts of a multidisciplinary team whose ultimate goal is to achieve better results when compared to the natural history of the pathology. The role of adjuvant treatment modalities such as radiosurgery and endovascular embolization is discussed. Treatment strategies and surgical results from a personal series of 344 patients operated in a ten-year period are reviewed. The Spetzler and Martin classification was modified to include subgroups IIIA (large size grade III AVMs) and IIIB (small grade III AVMs in eloquent areas) to assist the surgical resection criteria. The treatment strategy followed was surgery for grades I and II, embolization plus surgery for grades IIIA, radiosurgery for grades IIIB, and conservative for grades IV and V. According to the new proposed classification 45 (13%) patients were grade I, 96 (28%) were grade II, 44 (13%) grade IIIA, 97 (28%) grade IIIB, 45 (13%) grade IV, and 17 (5%) were grade V. As for surgical results 85.8% of the patients had a good outcome (no additional neurological deficit), 12.5% had a fair outcome (minor neurological deficit), 0.6% had a bad outcome (major neurological deficit), and 1.2% died. These figures indicate that the treatment of arteriovenous malformations can achieve better results compared to the natural history if managed by a well trained group of specialists led by an experienced neurosurgeon.

Brain↗
PubMed1998

Microsurgical anatomy of the dural collar (carotid collar) and rings around the clinoid segment of the internal carotid artery.

OBJECTIVE: To examine the relationship of the clinoid segment of the internal carotid artery to the structures in the roof of the cavernous sinus and to determine whether this segment is neither intradural nor intracavernous, as recently proposed. METHODS: The region of the roof of the cavernous sinus was dissected and examined using 3 to 40x magnification and micro-operative techniques. RESULTS: The clinoid segment was located within a collar formed by the dura lining the medial surface of the anterior clinoid process, the posterior surface of the optic strut, and the upper part of the carotid sulcus. The clinoid segment and the collar were defined above by the upper ring formed by the dura extending medially from the upper surface of the anterior clinoid process to surround the artery and below by the lower ring formed by the dura extending medially from the lower surface of the anterior clinoid process. The upper ring was adherent to the wall of the artery, but the lower dural ring was separated from the lower margin of the clinoid segment by a narrow space that admitted venous tributaries of the cavernous sinus, called the clinoid venous plexus. This venous plexus narrowed as the upper ring was approached and became wider at the lower ring, where the plexus communicated with the venous channels of the cavernous sinus. The upper and lower dural rings were best defined along the lateral and anterior margins of the artery, were less distinct medially, and disappeared posteriorly, where the dura forming the upper and lower rings came together. CONCLUSION: The clinoid segment is intracavernous, being located within a collar of dura in which venous tributaries of the cavernous sinus course. The implications of these findings for surgery are reviewed.

Carotid Artery, Internal↗
PubMed1998

Transchoroidal approach to the third ventricle: an anatomic study of the choroidal fissure and its clinical application.

OBJECTIVE: We review the anatomic features of the lateral ventricle, the foramen of Monro, the third ventricle, and the choroidal fissure, and we describe the transchoroidal approach to the third ventricle. This approach consists of opening the taenia fornicis of the choroidal fissure in the body of the lateral ventricle and approaching the third ventricle between the two internal cerebral veins. This route allows further posterior enlargement of the foramen of Monro without sacrificing any neural structures. When necessary, the anterior septal vein can be sacrificed. METHODS: Twenty adult cadaveric brains and four adult cadaveric heads were studied, using a magnification ranging from 3 times to 40 times, after perfusion of the arteries and veins with colored latex. RESULTS: The choroidal fissure is a natural cleft between the thalamus and the fornix, and it is identified by following the choroid plexus in the lateral ventricle. The choroid plexus in the body of the lateral ventricle originates from the tela choroidea of the roof of the third ventricle and is apparently attached to the fornix by the taenia fornicis and to the thalamus by the taenia choroidea. The taenia is actually the ependyma that covers the internal wall of the ventricular cavity and the choroid plexus. CONCLUSION: An understanding of the choroidal fissure is fundamental for use of the transchoroidal approach. Unlike transforaminal, subchoroidal, subforniceal, and interforniceal approaches to the third ventricle, which sacrifice some neural or vascular structures, the transchoroidal approach follows a natural route, and certainly it is one of the options to be considered when entry into the third ventricle is required.

Cadaver↗
PubMed1998

Multidisciplinary approach to arteriovenous malformations.

The treatment of arteriovenous malformations (AVMs) depends on the efforts of a multidisciplinary team whose ultimate goal is to achieve better results when compared to the natural history of the pathology. The role of adjuvant treatment modalities such as radiosurgery and endovascular embolization is discussed. Treatment strategies and surgical results from a personal series of 344 patients operated in a 10-year period are reviewed. The Spetzler and Martin classification was modified to include subgroups IIIA (large size grade III AVMs) and IIIB (small grade III AVMs in eloquent areas) to assist the surgical resection criteria. The treatment strategy followed was surgery for grades I and II, embolization plus surgery for grade IIIA, radiosurgery for grade IIIB, and conservative for grades IV and V. According to the new proposed classification 45 (13%) patients were grade I, 96 (28%) were grade II, 44 (13%) grade IIIA, 97 (28%) grade IIIB, 45 (13%) grade IV, and 17 (5%) were grade V. As for surgical results 85.8% of the patients had a good outcome (no additional neurological deficit), 12.5% had a fair outcome (minor neurological deficit), 0.6% had a bad outcome (major neurological deficit), and 1.2% died. These figures indicate that the treatment of AVMs can achieve better results compared to the natural history if managed by a well trained group of specialists led by an experienced neurosurgeon.

Arteriovenous Malformations↗
PubMed1997

Management strategies for posterior cerebral artery aneurysms: a proposed new surgical classification.

In a period of 10 years fifteen patients bearing sixteen aneurysms arising at the posterior cerebral artery were operated at our institution. Based on the approaches selected for each location a division of the posterior cerebral artery into three surgical segments is proposed. The first segment (S1), or anterior extends from the basilar artery bifurcation to the point where the artery reaches the level of the most lateral edge of the cerebral peduncle, the second segment (S2), or middle extends from the posterior limit of S1 to a point located just before the most medial extent of the artery in the quadrigeminal cistern (collicular point), and the third segment (S3), or posterior corresponds to the collicular point and to the portions of the posterior cerebral artery distal to it. Utilizing the concept of surgical segments all aneurysms in our series were satisfactorily exposed. Those arising at the S1 segment (8 cases) were operated either through a pterional or a pretemporal approaches; those from the S2 segment (6 cases) were operated either via the subtemporal or the subtemporal transventricular routes; and that arising from the S3 segment (1 case) was managed through the occipital interhemispheric approach. Among the aneurysms eleven were small, one was large, and four were large or giant. Ten of these aneurysms were surgically clipped, two coagulated, three treated by trapping and in one case the aneurysm was resected and the posterior cerebral artery was reconstructed by a termino-terminal anastomosis. The surgical results were considered good in all cases but one, where the patient died due to clinical complications three months after surgery. It is our belief that the use of this classification can provide the means to best select the most appropriate surgical approach to treat aneurysms arising at the posterior cerebral artery.

Adolescent↗
PubMed1997

Arteriovenous malformations of the basal ganglia region: rationale for surgical management.

Surgical indications for arteriovenous malformations (AVMs) arising at the region of the basal ganglia are questionable and the majority of cases are considered inoperable. Albeit not free from risks of morbidity and mortality, the treatment of choice is usually radiosurgery for small lesions, and embolization plus radiosurgery for larger lesions. Nevertheless, some lesions may be amenable for surgical resection due to their favorable location. Eighteen cases of such AVMs were selected for a direct approach in our series. Seventeen cases were classified as Spetzler and Martin [22] grade III, and one case was a grade V. Ten patients were males and eight females. The mean age was 28.3 years (ranged from 2 to 43 years). Sixteen patients had had previous hemorrhagic events prior to hospital admission. Eleven patients had pre-operative well established neurological deficits, and seven patients although symptomatic had a normal neurological exam at admission. Fifteen patients had their AVMs completely resected. Among the eleven patients with previous neurological deficits nine had no change in their pre-operative condition and two experienced postoperative neurological worsening. In the long-term follow-up six patients had a complete recovery and five recovered only partially. Among the seven patients whose neurological examination was normal pre-operatively five remained unchanged, one had a transient motor deficit, and one died due to a thalamic venous infarction and massive bleeding into the thalamus. The anatomical knowledge and the precise localization of the arteriovenous malformation through the aid of neuroimage studies has provided the means to classify these AVMs and plan operative strategies for some small selected cases with relatively low morbidity.

Adolescent↗
PubMed1997

Microsurgical anatomy of the transcondylar, supracondylar, and paracondylar extensions of the far-lateral approach.

Despite a large number of reports of the use of the far-lateral approach, some of the basic detail that is important in safely completing this exposure has not been defined or remains poorly understood. The basic far-lateral exposure provides access for the following approaches: 1) the transcondylar approach directed through the occipital condyle or the adjoining portions of the occipital and atlantal condyles; 2) the supracondylar approach directed through the area above the occipital condyle; and 3) the paracondylar exposure directed through the area lateral to the occipital condyle. The transcondylar approach provides access to the lower clivus and premedullary area. The supracondylar approach provides access to the region of, and medial to, the hypoglossal canal and jugular tubercle. The paracondylar approach, which includes drilling of the jugular process of the occipital bone in the area lateral to the occipital condyle, provides access to the posterior portion of the jugular foramen and to the mastoid on the lateral side of the jugular foramen. In this study, the anatomy important to completing the far-lateral approach and these modifications was examined in 12 cadaveric specimens. In the standard posterior and posterolateral approaches, an understanding of the individual suboccipital muscles is not essential. However, these muscles provide important landmarks for the far-lateral approach and its modifications. Other important considerations include the relationship of the occipital condyle to the foramen magnum, hypoglossal canal, jugular tubercle, the jugular process of the occipital bone, the mastoid, and the facial canal. These and other relationships important to completing these exposures were examined in this study.

Adult↗
PubMed1996

Anatomical and technical aspects of the contralateral approach for multiple aneurysms.

Microsurgery of multiple aneurysms is still a controversial subject. In order to avoid the risk of rebleeding and the consequent increase in morbidity in such cases all aneurysms or at least as many aneurysms as possible should be treated in the first operative procedure. To reach that goal aneurysms located on the contralateral side should also be considered for clipping during the first operation. Between 1984 and 1994 a series of 51 patients harboring multiple aneurysms of which 55 aneurysms were located on the contralateral side of the craniotomy were operated at our institution. No mortality or morbidity could be directly ascribed to the aneurysm that was clipped contralaterally. Based on that series we have described the anatomical features, technical aspects and surgical difficulties of approaching bilateral aneurysms through the same craniotomy.

Aneurysm, Ruptured↗
PubMed1995

The pretemporal approach to the interpeduncular and petroclival regions.

A pretemporal approach to the interpeduncular and petroclival regions is described. Through a frontotemporal craniotomy based very low in the middle fossa the temporal lobe is completely exposed. The Sylvian, carotid, chiasmatic, and lamina terminalis cisterns are widely opened. The arachnoid fibers between the uncus and the frontal lobe, as well as those binding the temporal lobe to the tentorial edge and to the oculomotor nerve are also separated. The bridging veins from the temporal pole to the spheno-parietal sinus are usually coagulated and sacrificed allowing for posterior displacement of the temporal lobe. The approach combines the advantages of both the classical pterional and subtemporal approaches providing unhindered exposure of the anterior portion of the tentorial incisura in dealing with vascular and tumoural lesions arising at the sellar, parasellar, and interpeduncular regions, and at the superior aspect of the petroclival region.

Basilar Artery↗