Biomedical subjects

R Ramos-Zúñiga

Publications and source records attributed to R Ramos-Zúñiga.

3 recordsLinked to original sources

PubMed1999

The trans-supraorbital approach.

The trans-supraorbital approach represents the advantage of combining the keyhole principle and skull base surgery. In cadaveric work the author shows the anatomic fields visualized with this procedure, advantages and potential surgical applications. The experimental surgical procedure was performed on 8 adult skulls and on 3 cadavers with intact cerebral structures. First, a 2 cm supraorbital approach for endoscopic exploration was used. The basic anatomic landmarks and corresponding dimensions of the microsurgical field were recorded and then compared with those from the trans-supraorbital approach, after removing the orbital arch and other parts of the orbital ceiling. This technique offers a 0.5 cm average increase in surgical field from the craniotomy. The surgical distance that results is shorter (about 2 cm), as well as the length of the surgical instruments required. A better microscope illumination in the deep fields, and the possibility of access to the intraorbital region, the superior orbital fissure, the optic foramen, and the cavernous sinus through the clinoid space are also obtained, with minimal cerebral retraction and similar advantages as through the pterional trans-sylvian approach. The author concludes that by extending the craniotomy and decreasing the surgical distance, the microsurgical field is more convenient for microscope-assisted surgery without totally relying on the endoscope, and with minimal brain retraction. It also provides multiple options to approach vascular and tumor lesions found in these microsurgical corridors, combining principles of minimal invasion and skull-base surgery.

Adult↗

PubMed1998

Neuroprotection in selective focal ischemia in rats by nitrates, an alternative redox manipulation on nitric oxide: experimental model.

The recent advances in the histopathology of ischemia have set forth new proposals, particularly in regard to excitotoxicity by the glutamate receptor, NMDA. The participation of the nitric oxide (NO) in normal and pathological conditions and its relationship with toxicity in ischemia, suggest new alternatives for the modulation of the NMDA receptor REDOX site through its pharmacologic manipulation. This event would potentially limit the consequences of the activation-calcium flow and the production of peroxoinitrite during the ischemic phenomenon. The present work delivers two proposals: 1) A modified technique to the ones that have been described, of endovascular, without craniectomy, for experimental cerebral ischemia in Wistar rats, and with particular harmful effect upon the hippocampus. 2) It promotes the use of nitrates as an additional alternative to other elements, in order to restrict excitotoxicity in the described experimental cerebral ischemia, and paying attention to CA1-CA2 of the hippocampus. This area, specially sensitive to hypoxia-ischemia, offers an excellent study option for focal, experimental, cerebral ischemia associated with toxicity mediated by excitatory amino acids, since it stores an important concentration of NMDA receptors (R1/R2 A) as well as endothelial nitric oxide synthase. Our parameters are supported by quantitative-qualitative cell analysis, and not by the extension of the stroke which offers a more objective perspective upon the assessment of the focal ischemic event. By means of this technique, these results confirm the extent of the ischemic injury to the cell at the level of the hippocampus compared to a control/basal group, P = 0.0006. Furthermore, it suggests a neuroprotective effect of isosorbide dinitrate since it preserves the viable cells, and limits the appearance of hypoxic-ischemic cells at the hippocampus when the middle cerebral artery (MCA) is occluded endovascularly, as compared to the animals with no treatment P = 0.0080. However, other research lines are needed to compare the efficacy of this present work with other therapeutic proposals.

Animals↗

PubMedDate not supplied

[Cerebral death and bioethics].

INTRODUCTION: Brain death has been a topic of great interest for clinicians throughout the history of Neurosciences. There are so many different ideas about this topic that it has been necessary to constantly define further the criteria and medical decisions applicable in this field. Also about this matter there are a set of cultural, philosophical and religious aspects as well as autonomous principles in the people involved in such an event. Questions and dilemmas are still present in the individuality of every case and especially in terms of management of information and circumstances that define brain death. DEVELOPMENT: This essay tries to analyze the medical and historical issues around death and its relation to the context of brain death as such. There are also a series of reflections supported by the current bioethical thoughts that are identified with a cultural framework that is crucial to acknowledge the way in which the doctor, the family and society approach an event such as brain death. In spite of all the development of diagnostic technology and the extremes of the futility and extreme cruelty of treatments; there are still open questions that require to be looked into with objective criteria and scientific rigor. CONCLUSION: We should not put aside bioethical principles that are inherent to human quality and dignity that touch the sensitivity of those who give out the information and those who receive it within this process of interaction between the medical staff and the family.

Bioethics↗