Biomedical subjects

Francesco Tomasello

Publications and source records attributed to Francesco Tomasello.

21 records · Page 2Linked to original sources

PubMed2002

Microsurgical anatomic features of the lamina terminalis.

OBJECTIVE: The lamina terminalis (LT) is a structure of considerable interest for microneurosurgery, and precise knowledge regarding its normal anatomic features and the variations thereof is required. The purpose of this study, which was based on microanatomic dissection of human cadaveric specimens, was to review the microsurgical anatomic features of the LT and its neurovascular relationships. The surgical implications of the morphometric data are discussed. METHODS: The region of the LT was examined in 10 human cadaveric heads, obtained from 8 fresh adult cadavers and 2 formalin-fixed adult cadavers, and in 10 formalin-fixed, isolated, adult brains. An operating microscope was used for all dissections and measurements. RESULTS: Assuming the LT to be a triangular structure, we performed measurements of the distance between the midportion of the upper edge of the chiasm and the lower edge of the anterior commissure (height), which averaged 8.25 mm. The distance between the medial edges of the optic tracts (base) averaged 12.81 mm. The area averaged 52.84 mm(2). A minimal amount of retraction was needed to fully expose the LT, and generally there was no need to mobilize the anterior cerebral artery-anterior communicating artery complex. Perforating branches to the hypothalamus and optic apparatus are laterally located and do not interfere with LT incision and/or fenestration. CONCLUSION: The LT constitutes a clearly identifiable microsurgical target. The allowable extent of LT opening is sufficient to provide wide access into and free cerebrospinal fluid flow from the third ventricle. Fenestration of the LT is a safe procedure, provided that the relevant anatomic landmarks are identified and respected.

Adult↗

PubMed2002

Assessment of human brain water content by cerebral bioelectrical impedance analysis: a new technique and its application to cerebral pathological conditions.

OBJECTIVE: Total brain water content changes in several cerebral pathological conditions and the measurement of brain water content are important for the selection of appropriate therapeutic procedures. We present a quantitative, in vivo, bioelectrical impedance analysis (BIA) method and propose its use for the accurate assessment of brain water content among human subjects. METHODS: Cerebral BIA is based on the conduction of an applied current in the brain parenchyma. Application of an excitatory current of 800 microA at 50 kHz, via two electrodes placed on the eyelids with the eyes closed, and detection of the voltage drop with two electrodes placed in the suboccipital region allow brain resistance and reactance to be measured. By means of an equation that considers cranial circumference and resistance, it is possible to quantify the total brain water content, expressed as the bioelectrical volume. Cerebral BIA was performed with a series of healthy volunteers (n = 100), for determination of average brain water content values. The method was then applied to 50 patients with brain tumors (n = 20), intracranial hemorrhage (n = 16), or hydrocephalus (n = 14), for assessment of changes in global brain water contents. Data were compared with those obtained for healthy volunteers. RESULTS: Statistically significant differences (P < 0.001) were observed between the two groups. Mean brain water content values (expressed as bioelectrical volume values) were 38.2 +/- 3.9 cm2/Omega for healthy volunteers and 67.7 +/- 13.1 cm2/Omega for patients with cerebral pathological conditions. Statistically significant differences (P < 0.05) were also observed among patients with cerebral pathological conditions. CONCLUSION: The results of this study suggest that BIA, applied to the cerebral parenchyma, is a valid method for the prediction of brain water contents under both normal and pathological conditions. However, further studies are needed to establish whether it is sensitive and reliable enough for future clinical applications.

Adolescent↗

PubMed2002

Does administration of recombinant human erythropoietin attenuate the increase of S-100 protein observed in cerebrospinal fluid after experimental subarachnoid hemorrhage?

OBJECT: Results of recent studies indicate that erythropoietin (EPO) produces a neuroprotective effect on experimental subarachnoid hemorrhage (SAH). It has been reported that S-100 protein levels increase in cerebrospinal fluid (CSF) after SAH, providing a highly prognostic indication of unfavorable outcome. This study was conducted to validate further the findings of S-100 protein as an index of brain damage and to assess whether treatment with recombinant human EPO (rhEPO) would limit the increase of S-100 protein level in CSF following experimental SAH. METHODS: Thirty-two rabbits were each assigned to one of four groups: Group 1, control; Group 2, SAH; Group 3, SAH plus placebo; and Group 4, SAH plus rhEPO (each group consisted of eight rabbits). The rhEPO and placebo were administered to the rabbits after SAH had been induced, and S-100 protein levels in the CSF of these animals were measured at 24, 48, and 72 hours after the experimental procedure. In each group of animals levels of S-100 protein were compared with the mortality rate, neurological outcome, and neuronal ischemic damage. High S-100 protein levels were found in rabbits in Groups 2 and 3, which exhibited poor neurological status and harbored a high number of damaged cortical neurons. Favorable neurological outcome and significant reductions in total numbers of damaged neurons were observed in animals in Group 4 in which there were significantly lower S-100 protein concentrations compared with animals in Groups 2 and 3 (p < 0.001). CONCLUSIONS: The results of this study support the concept that determination of the S-100 protein level in CSF has prognostic value after SAH. The findings also confirm that rhEPO acts as a neuroprotective agent during experimental SAH.

Animals↗