Infrared Spectrophotometry Studies on Cerebral Tumor s-RNAs

Deuterated s-RNAs prepared from a medulloblastoma, a glioblastoma and a frontal lobe show a different relative intensity in the 1680 cm–1 band. The phenomenon can be related to the frequency in the base pairings; it may depend either on a proportionally different content of t-RNAs and/or on qualitative variations in the primary and secondary structure of the polynucleotides. Irrespective of the kind of variation and its causes, the finding once more proves the existence of chemical differences between neuroectodermal tumors, with an undifferentiated and those with an atypical cellular component.

Gunshot wounds to the head in the 16th century

DEVELOPMENT OF FIREARMS in the 16 century produced profound changes in the art of warfare and raised new problems for the physician-surgeons. Old assumptions and wrong interpretations delayed the rational approach to the head injuries inflicted by missiles. Evolution of thought and increased experience over the century ultimately led to a surgical practice that can be regarded as the best possible solution allowed by contemporary knowledge and technology.

The spinal cord and its roots according to Galen

Galen's methodological approach to medicine anticipated modern rules. His experiments on the spinal cord contributed greatly to our knowledge of this structure by reporting the variegated pattern of neurological impairment after sectioning at different levels. His approach to injuries of the spinal roots and peripheral nerves documents both diagnostic skill and intellectual honesty.

Return to Galen

AT THE BEGINNING of the previous century, the English editor of a minor work by Galen called for a return to that ancient scholar after centuries of neglect. The appeal did not meet with success. Galen's reputation is currently based on renown arising from tradition, rather than an awareness of his actual contributions to medical science. His methodological approach to experimental medicine seems to have fallen into obscurity, although it anticipated modern principles. This report reviews the rise and fall in popularity of Galen's medical works, in an attempt to highlight the circumstances that still prevent a full appreciation of those writings.

Immunoscintigraphic detection of the ED-B domain of fibronectin, a marker of angiogenesis, in patients with cancer

PURPOSE

ED-B fibronectin is expressed only during angiogenic processes and in tissues undergoing growth and/or extensive remodeling. We demonstrated previously the possibility to target and selectively deliver therapeutic substances to tumor vasculature in experimental animal models using a human recombinant antibody fragment, L19, specific for the ED-B domain of fibronectin. Here we evaluate the possibility of targeting primary tumors and metastatic lesions in cancer patients through immunoscintigraphy using (123)I-labeled dimeric L19 [L19(scFv)(2)].

EXPERIMENTAL DESIGN

Twenty patients (34-79 years of age) with lung, colorectal, or brain cancer, whose tumors had been confirmed by imaging techniques and/or histologically, were admitted to the immunoscintigraphic investigation.

RESULTS

The dimeric L19 antibody selectively localized in tumor lesions in aggressive types of lung cancer and colorectal cancer. Because ED-B fibronectin is expressed only during angiogenic processes and in tissues undergoing growth and/or extensive remodeling, L19(scFv)(2) is able to distinguish between quiescent and actively growing lesions. No side effects were observed.

CONCLUSIONS

The ability of L19(scFv)(2) to target tumors in patients provides the foundations for new therapeutic applications, in which the L19 antibody is engineered to selectively deliver bioactive molecules to primary tumors as well as to metastases.

Differentiation between high- and low-grade astrocytoma using a human recombinant antibody to the extra domain-B of fibronectin

Different fibronectin (FN) isoforms are generated by the alternative splicing of the primary FN transcript. We previously demonstrated that the isoform containing the extra domain B sequence of fibronectin (B-FN), a complete type-III-homology repeat, is a marker of angiogenesis that accumulates around neovasculature only during angiogenic processes. We produced a single-chain human recombinant antibody (scFv), L19, which reacts specifically with B-FN and selectively targets tumor vasculature in vivo. We used this scFv and an antibody against a pan-endothelial marker (Factor VIII) in a double-staining procedure on specimens of low- and high-grade astrocytomas to determine the percentage of B-FN-positive vessels, (denominating the resulting value angiogenic index [AI]). Compared to vascular density and proliferative activity (evaluated using antibodies to Factor VIII and Ki67, respectively), AI correlated better with tumor grade (1.6 +/- 2.6% and 92.0 +/- 8.7% of B-FN-positive vessels in low- and high-grade astrocytomas, respectively) and was a more precise diagnostic tool than either of the two conventional methods. In fact, discriminating analysis using these three parameters showed that only AI accurately classified 100% of the cases studied, compared to 64% and 89% correctly diagnosed by vascular density and of proliferating cells, respectively.

A craniocerebral infectious disease: case report on the traces of Hippocrates

A modern case of complicated sinusitis, with osteitis of the cranium and intraorbital-intracranial empyema, closely corresponds to descriptions reported in the Hippocratic treatise Diseases II. The therapeutic measures suggested in that work can be regarded as suitable according to modern practice. An ancient physician who followed the Hippocratic doctrine probably would have been able to recognize this complicated disease and possibly save the patient.

Occurrence of a glioblastoma-associated tenascin-C isoform in cerebral cavernomas and neighboring vessels

OBJECTIVE

Regrowth of cerebral cavernomas after apparently complete excision, de novo occurrence, and evidence of proliferation-related patterns raise the question as to their intrinsic growth potential. A particular isoform (Type III repeat c) of the glycoprotein tenascin-C (TN-C), typically associated with the vessels of anaplastic gliomas, is regarded as a marker of vascular proliferation in lesions growing within brain tissue. This study sought to ascertain whether this isoform is expressed in cerebral cavernomas to gain further insight into the growth potential of these lesions.

METHODS

Sixteen cerebral cavernomas and three fragments of normal brain underwent immunohistochemical examinations via two antibody fragments obtained by phage display technology. Previous characterization demonstrated that the fragment TN-12 recognizes the epidermal growth factor-like repeat, common to all TN-C isoforms. On the contrary, the fragment TN-11 was found to be highly specific for the Type III repeat c isoform.

RESULTS

Accumulation of total TN-C was found in the vascular walls and in the interspaces between the blood cavities of all examined cavernomas. When the antibody fragment TN-11 was used, staining of the subendothelial layers occurred in both the bulk of the cavernomas and vessels of the white matter surrounding the lesions, but staining was absent in the control specimens.

CONCLUSION

The distribution of the Type III repeat c isoform of TN-C, a putative marker of vascular proliferation, within cerebral cavernomas is consistent with the hypothesis of a growth potential of cerebral cavernomas. Enlargement of these lesions might involve recruitment of neighboring vasculature, which is possibly dependent on environmental conditions.

The subchoroidal approach to the third ventricle: surgical anatomy according to Galen

THE SUBCHOROIDAL APPROACH has taken its place among the surgical access routes to the third ventricle. Eighteen centuries ago, in his major anatomic work, Galen detailed with astonishing accuracy the anatomy of the structures around the third ventricle and the procedure for exposing this cavity by entering the lateral ventricles and elevating its roof. Even more surprising is Galen's pioneering description of surgical maneuvers of the third ventricle in living animals in a way that anticipated the modern subchoroidal approach.

The fatal wound of Hector, according to a drawing by Peter Paul Rubens designed for tapestry weaving

According to the Iliad(Chapter XXII, Verses 322-329), Hector, while fighting his last duel, was almost entirely protected by bronze armor, with only a small area "where the clavicle marks the boundary between neck and thorax" exposed. It was precisely into this area, "the shorter way to death," that Achilles thrust his lance. This fatal wound, although covering Hector with blood, allowed the victim to pronounce a few words. In designing the Story of Achilles, his fourth and last series of drawings especially designed for tapestry weaving, Rubens depicted Achilles stabbing Hector near the midline of his neck. There is evidence that Rubens was always well acquainted with the literary sources of his pictures. It is also likely that he became familiar with contemporary editions of the Iliad that were enhanced with commentaries. Realizing that the wound depicted in his original drawing should have prevented Hector from speaking, Rubens altered the scene, then showing the lance piercing the cervical vascular bundle. The careful scrutiny for literary accuracy that was typical of Rubens' artistic behavior did not prevent an additional minor imprecision in the final tapestry. Nevertheless, his outstanding expressive power enabled him to give form to a gigantic baroque representation of the death of Hector in masterly fashion.

Autoregulation of cortical blood flow during surgery for ruptured intracranial aneurysms

BACKGROUND

Little information is available about the extent and the time course of possible impairment of cerebral circulation occurring after aneurysmal subarachnoid haemorrhage (SAH). The aim of this study was to correlate cerebral autoregulation, neurological impairment at surgery and timing of surgery in patients with ruptured intracerebral aneurysms.

METHODS

Cortical blood flow (CoBF) was measured intraoperatively by a thermal diffusion probe in 77 patients during surgery for ruptured supratentorial aneurysms, who were operated on at different time intervals after bleeding. An autoregulation index (AI), expressed as the ratio between the change in CoBF and the change of mean arterial blood pressure at the time of rising the systemic blood pressure after occlusion of the aneurysm(s), was determined in each case.

RESULTS

Among good-grade patients (WFNS grade I-II), those operated on days 0-2 after SAH had a significantly better autoregulatory response, compared either with patients who underwent surgery on days 3-7 after bleeding (p<0.01), or with those whose aneurysm was occluded more than 7 days after rupture (p<0.03). The mean AI of poor-grade patients (WFNS grade IV-V), who received surgery on days 0-2 after SAH, was significantly higher (p<0.01) compared with the corresponding value of good-grade patients. No significant difference was found between the mean AIs of patients who subsequently did, or did not, develop symptomatic vasospasm.

CONCLUSIONS

It is concluded that good-grade patients operated on within 48 hours after bleeding take advantage of a preserved autoregulatory function during controlled hypotension.

Evaluating the cost effectiveness of newer psychotropic medications

With the introduction of newer, more expensive psychotropic medications, pharmacists must consider the cost-effectiveness issues related to the use of these drugs. In general, the newer agents are more effective than conventional drugs, have improved side-effect profiles, and are associated with a lower rate of recidivism. However, because of cost constraints, not every patient who needs a newer psychotropic drug has the opportunity to receive it. To provide these patients with the medication they need, we must look beyond the acquisition cost of the drug and focus on the global impact of the medication on the total mental health budget at a facility. Data from this point of view can justify the greater expense of the medication, and more importantly, the patient can be better served. Cost-effectiveness data from one's own institution may be more convincing to formulary committee members than data from academic centers and can help make newer, more expensive agents available to the patients who need them. Designing and implementing a retrospective study is one means of obtaining these cost-effectiveness data.

Postero-lateral microsurgical approach to orbital tumors

A modification of the lateral orbitotomy is reported for the microsurgical approach to tumors located in the posterior intraconal space. The orbital apex is entered through a small bone opening on the orbital and temporal portions of the greater wing of the sphenoid, with the lesser sphenoidal wing, the orbital plate of the frontal bone, and the lateral orbital rim being left intact. This surgical technique was employed in 8 cases of pure apical tumors, out of a consecutive series of 103 orbital growths. It proved to be reliable with regard to either adequate exposure and radical excision of the lesions or low rate of operative morbility.

Tenascin distribution in human brain tumours

Using a monoclonal antibody specific for human tenascin (TN), 180 intracranial growths were immunohistochemically studied. In 69 cases of meningioma, neoplastic cells were negative, with some positivity being observed only in the perivascular and the supporting stroma, especially in anaplastic meningiomas. In 57 cases of glioma different degrees of reactivity occurred in both the cellular conglomerates and the stromal components of the tumours. A higher variability in reactivity was observed in anaplastic astrocytomas and glioblastomas. The most constant finding of the study was the staining of the stroma, which was observed in all types of growths, including metastasis, abscess and tuberculoma. The results are consistent with the hypothesis that tenascin is a stromal marker rather than a true marker of malignant tumours. The heterogeneous distribution of TN in anaplastic gliomas may be a factor in the variable response to treatment with radiolabelled anti-TN monoclonal antibodies.

Delayed worsening of the surgical correction of angular and axial deformity consequent to burst fractures of the thoracolumbar or lumbar spine

Forty-one patients with burst fractures of the thoracolumbar junction, or the lumbar spine (T12 to L5), were followed for 6-48 months (mean follow-up = 19.9 months) after early surgery (usually within 24 hours). Preoperative, early postoperative, and late postoperative degrees of kyphosis, as well as percent reduction of the height of the vertebral body were calculated and compared. Early postoperative radiologic evaluations showed a statistically significant difference (p < 0.0001) between the mean values of both parameters calculated respectively before and after surgery. The decrease of the surgical correction, from the initial postoperative radiographs to follow-up, was statistically significant (p < 0.0001). However, the final values were better when compared with the preoperative features (p < 0.003 and p < 0.0001, respectively for degree of kyphosis and reduction in vertebral height.

Longitudinal study of cerebral blood flow following early or delayed surgery for ruptured intracranial aneurysms

Out of a series of 43 cases operated on for ruptured intracranial aneurysms over a 12-month-period, 32 patients were followed up to 12 months postoperatively with repeated evaluations of cerebral blood flow, using the Xenon133 inhalation technique. No statistically significant differences in cerebral perfusion were detected between the subgroups of good-grade patients, who were submitted respectively to early, or delayed surgery. Depression of flow in the affected hemisphere of poor-grade patients was principally related to the preoperative occurrence of an intracerebral haematoma. The overall results were not consistent with the hypothesis that early surgical intervention results in long-lasting effects on the cerebral circulation.

Infratentorial ischaemia following experimental cerebellar haemorrhage in the rat

Early changes of cerebellar and cerebral blood flow, as well as subsequent infratentorial ischaemia, were evaluated in an experimental model of cerebellar haemorrhage. Eight anaesthetized male adult Sprague-Dawley rats received an injection of autologous arterial blood (50 microliters) into the right cerebellar hemisphere. Eight animals were sham-operated and served as controls. Cerebellar blood flow, measured at regular time intervals in the hemispheric cortex ipsilateral to the lesion by the hydrogen clearance method, was significantly depressed in the experimental group as compared with the control animals. This drop in cerebellar blood flow was evident 5, 30, 60, 90, and 120 min postoperatively, with a return to pre-injection values recorded 180 min after surgery. No significant difference in supratentorial blood flow was detected over the entire period examined between the two groups of animals. Enzyme histochemistry demonstrated areas of ischaemia around the clot and within the brain stem in animals with an intracerebellar haemorrhage at the end of the experiment. These results provided evidence of ischaemic damage within the infratentorial compartment after the induction of experimental cerebellar haemorrhage.

Cortical blood flow recorded during early or delayed surgery for ruptured intracranial aneurysms

Forty-three patients were operated on for ruptured intracranial aneurysms during a 12-month-period. Intraoperative evaluation of cortical blood flow by means of a thermal diffusion probe was performed in 23 out of the 41 patients who were operated on for aneurysms of the anterior circulation. The autoregulation index was determined at the time of raising the systemic blood pressure after clipping of the aneurysm(s). No statistically significant difference was found between the averages of the autoregulation indexes calculated in the subgroups of patients submitted respectively to early or delayed surgery. There was no correlation of both cortical blood flow and autoregulation with either age of the patients, or preoperative neurological grade. On the contrary, the autoregulation index showed a statistically significant correlation with outcome.

Transpedicular decompression and stabilization of burst fractures of the lumbar spine

Twenty-seven consecutive patients with neurological impairment due to burst fractures of the lumbar spine were operated upon, via the postero-lateral route, over a 38-month-period. Transpedicular fixation devices [posterior segmental fixator (PSF) or variable screw placement system (VSP)] were applied in all cases, in order to achieve short-segment fusion of the fractured spinal segment. Return to useful motor power or neurological normality (median follow-up: 18.7 months) occurred in 22 cases (81% of the whole series), with this outcome resulting in all but one of the cases with preoperative incomplete neurological deficit. Postoperative encroachment of the spinal canal, degree of kyphotic deformity, and reduction of the vertebral height showed statistically significant differences compared with the corresponding preoperative values.

Subsequent bleeding from ruptured intracranial aneurysms treated by wrapping or coating: a review of the long-term results in 47 cases

Forty-seven patients, who underwent surgery over a 34-year period by the wrapping or coating of ruptured intracranial aneurysms, have been retrospectively evaluated. The following materials were used in the surgical procedures: muscle with gelatin sponge (7 cases), gauze (2 cases), oxidized cellulose with Biobond (28 cases), Histoacryl with gauze or fascia (10 cases). The patients were monitored for up to 37 years (mean, 13.7 +/- 8.2 yr). One or more subsequent bleedings occurred in eight patients (17%). Three patients had additional bleeding and died in the early postoperative phase (within 1 mo after surgery). In five patients, the subsequent bleeding occurred between 1 and 15 years postoperatively, with two fatalities. One patient experienced two recurrences. Therefore, the mortality rate for postoperative bleedings was 10.6% (five patients) in the whole series, and the incidence of early (within 1 mo after surgery) fatal bleedings was 6.4%. After the first month from the initial hemorrhage, the global risk of subsequent bleeding was 0.93%/yr. Among the nine patients whose aneurysms were wrapped with muscle, gelatin sponge, or gauze, four additional bleedings occurred, whereas four relapses were observed among the 38 cases treated by employing bioadhesive agents (P < 0.04; Fisher's exact test). The rate of further bleeding was higher (25%) in patients undergoing surgery in the premicrosurgical era compared with that (8.7%) recorded in patients treated by microsurgery (difference statistically not significant).

Near-anatomical reduction and stabilization of burst fractures of the lower thoracic or lumbar spine

Thirty-one consecutive symptomatic patients with burst fractures of the lower thoracic or lumbar spine (T 11-L4) were treated by early surgery in a 36-month period, with near-anatomical reduction being achieved via the postero-lateral route. Fusion and reconstruction of the vertebral body was done by using autologous or processed bovine bone. Correction of the kyphotic deformity was obtained by using distraction rods or transpedicular devices. The post-operative mean degree of kyphosis, percent vertebral height, and percent canal stenosis showed statistically significant differences, compared with the corresponding pre-operative mean values. All but one of the 25 patients with incomplete paraplegia exhibited neurological improvement, with complete recovery occurring in 20 cases (median follow-up: 16 months) irrespective of the location of the lesion at the thoraco-lumbar junction (T 11-L1) or the lower lumbar segment (L2-L4). Out of the 6 patients with pre-operative complete paraplegia, useful motor power returned in one case with a lesion below L1. The results confirm the suitability of the postero-lateral route and are consistent with the assumption that early near-anatomical reduction and stabilization favours maximum neurological recovery in symptomatic patients.

Muscle basal lamina as a grafting material for elongation of axons from rat brain

Autografts of peripheral nerve or allografts of muscle basal lamina were inserted into the putamen-caudate complex of rats, with the outer end of the implant being sutured to the temporalis muscle. Elongation of central axons within the grafts, as revealed by the horseradish peroxidase retrograde labelling technique, did occur in the presence of basal lamina implants. With both types of grafting materials stained neurones exhibited a comparable distribution, being mainly found in the proximity of the central tip of the grafts. However, labelled cells in the presence of basal lamina were limited in number, compared with peripheral nerve autografts. Therefore, the usefulness of implants of muscle basal lamina into the central nervous system, in order to direct regenerating central axons toward distant target regions, is limited. This material might be suitable, as an alternative grafting material, in experimental models where avoidance of neurological impairment or size and length of the graft are crucial factors.

Penetrating craniocerebral missile injuries in civilians: a retrospective analysis of 314 cases

Analysis of 314 cases of penetrating craniocerebral missile injuries in civilians revealed a high rate of early mortality, with 228 victims having died at the scene and a further 38 dead within 3 hours. Surgery was performed in 44 patients who had a preoperative Glasgow Coma Score of at least 4. Out of the 26 survivors, all operated upon, 19 had an adequate recovery (score of 0-3 on the expanded Glasgow Outcome Scale). Vigorous resuscitation and early surgery often resulted in useful survivals and occasionally in spectacular recoveries. However, the high mortality rate on the scene or soon after the injury restricted the possibility of effective management to a minority of cases.

Changes in infratentorial blood flow following experimental cerebellar haemorrhage. A preliminary report

The temporal progression of changes in blood flow within the hemispheric cerebellar cortex, following an experimental cerebellar ipsilateral haemorrhage, was investigated in rats by using the hydrogen clearance technique. Stereotactical injection of 50 microliters of fresh autologous blood into the paramedian white matter was found to produce an early drop of cerebellar blood flow, with subsequent rise toward higher values. An increase of the intracranial pressure only occurred at the time of injection of blood. Arterial blood gases, mean arterial blood pressure and blood glucose levels did not exhibit significant changes. Histochemical evaluations of glycogen phosphorylase showed a posthaemorrhagic pattern of enzyme depletion, consistent with the occurrence of an ischaemic damage in both the cerebellum and the brain stem.

On the predictive value of radiological signs for the presence of dural lacerations related to fractures of the lower thoracic or lumbar spine

The predictive value of radiological signs for the presence of lacerations of the thoracolumbar dura in spine-injured patients could represent an important adjunct to the rationale for the optimal management, owing to the possible onset of early or delayed complications of these lesions. Occurrence of signs assumed to be related to dural tears, such as separation of the pedicles, fractures of the laminae, and encroachment of the spinal canal, was analyzed in a consecutive series of 25 patients submitted to surgical reduction and stabilization of the fractured lower thoracic or lumbar spine in a 24-month period. No statistically significant correlation was found between dural lacerations and any of the examined signs. Leaks of cerebrospinal fluid through traumatic breachs of the meninges were found in 16 of the 25 cases. The high rate of occurrence of dural lesions associated with fractures of the lower thoracic or lumbar spine adds a further argument to the aggressive approach to these injuries.

Regional cerebral blood flow after omental transposition to the ischaemic brain in man. A five year follow-up study

Regional cerebral blood flow, recorded by the 133Xenon inhalation method, was measured preoperatively and over a five years postoperative period in six patients with completed stroke and stabilized neurological deficits, who had undergone omental transposition for revascularization of the ischaemic brain. Comparisons of the preoperative blood flow values with those recorded following surgery demonstrate a postoperative increase of blood flow in five patients, with a high statistical degree of significance in four of them at the final examination. The flow increase was noted over the infarcted areas of the brain, upon which the omentum had been placed, as well as areas of the ischaemic hemisphere without omental placement and the contralateral hemisphere. Out of the five patients who demonstrated preoperative flow values below the expected norm for age, four showed final postoperative cerebral blood flow within the normal limits for their age. The results are consistent with the assumption that the transposed omentum played a role in postoperative blood flow increase, by adding collateral circulation to the ischaemic brain.

A plea for postero-lateral orbitotomy for microsurgical removal of tumours of the orbital apex

Lateral orbitotomy including the lateral rim of the orbit allows adequate surgical exposure for most intraorbital tumours. However, by dealing with intraconal lesions located deep at the orbital apex, the control of the posterior aspect of the growth is often less than optimal. The postero-lateral route, with bone removal mainly confined to the greater sphenoidal wing, allows a more direct approach to the posterior portion of these lesions along a plane tangential to the lateral aspect of the temporal pole. A modified surgical technique is reported, which in three consecutive cases allowed radical removal of pure apical tumours without added neurological deficits.

Gunshot wounds of the brain in civilians

A consecutive series of 178 civilians with gunshot wounds of the brain was retrospectively analyzed. The overall mortality was 93%, with 88% of the victims having succumbed within 3 hours. Surgery was performed in 21 cases, all with a Glasgow Coma Score of 6 or more. Out of the 12 survivors, 9 exhibited minor neurological signs at the time of discharge. Good outcome occasionally resulted in patients with lesions crossing the midline, or affecting two lobes of a single hemisphere. Although spectacular recoveries in individual patients with apparently devastating injuries can be regarded as a sufficient basis for an aggressive approach, including vigorous resuscitation and early surgery, bleak possibilities still exist as to the management of civilian gunshot wounds, owing to the high mortality rate on the scene, or soon after the injury.

Axonal elongation into peripheral nerve grafts between thalamus and somatosensory cortex of the rat. An experimental model

After destruction of the thalamocortical projections of one side in 12 adult rats, the ipsilateral thalamic ventrobasal nucleus was connected with the contralateral somatosensory cortex through an autologous peripheral nerve graft. Three months after the implanting procedure, horseradish peroxidase was applied to the transected nerve. Retrograde labeling of cells occurred in all examined animals. Evidence of newly formed thalamocortical connections provides the experimental basis to a model suitable for functional evaluations.

Computed tomography and magnetic resonance imaging of cerebral coenurosis

A case of Coenurus cerebralis involving both cerebral hemispheres and the interpeduncular cistern is presented to illustrate the computed tomography (CT) and magnetic resonance imaging (MRI) features. In CT scans viable cysts appear as lucent lesions surrounded by a contrast-enhanced peripheral rim. By using multiple echo sequences the cyst content is characterized in magnetic resonance images by a cerebrospinal fluid-like intensity pattern.

Computed tomography and magnetic resonance imaging in spinal hydatidosis

Computed tomography and magnetic resonance imaging in patients with spinal hydatidosis provide comprehensive evaluation of the actual extent of the disease. Paravertebral uncalcified cysts, hardly recognizable by conventional radiologic examinations, are clearly shown by both methods. Initial involvement of the spongy bone is evident in computed tomography scans, in contrast to what usually appears to be normal in plain films or tomograms. Occurrence of cysts within the spinal canal is revealed by both types of computed scans, with magnetic resonance imaging being able to provide further information on the involvement of the spinal cord.

[Anatomo-surgical classification and surgical treatment of arteriovenous malformations in the posterior cranial fossa]

An increasing number of arteriovenous malformations of the posterior cranial fossa can be radically extirpated with good functional results, by using microsurgical techniques. Extensive involvement of the brain stem represents the limit for effective surgery. An anatomo-surgical classification of these lesions is presented, and the surgical indications are discussed.

Long-term results of surgical treatment for redundant roots of the cauda equina

Seven patients with redundant roots of the cauda equina were followed 2 1/2-10 years after surgical decompression. Improvement of signs and symptoms occurred in all patients. However, none of them was neurologically intact at the time of the last physical examination, although persistence of minimal neurological signs and/or occasional pain did not prevent a useful occupational activity.

Omental transposition or transplantation to the brain and superficial temporal artery--middle cerebral artery anastomosis in preventing experimental cerebral ischaemia

Transposition of lengthened omentum to the brain surface, transplantation of an omental graft, or superficial temporal artery--middle cerebral artery anastomosis were performed in dogs prior to transcranial occlusion of the ipsilateral middle cerebral artery at its origin, including the bifurcation of the internal carotid artery. Both omentum and by-pass were able to reduce the changes in cerebral blood flow, somatosensory evoked responses, cerebral water and electrolyte content, consequent to the ischaemic insult. In the experimental conditions adopted in this study, the effect of omental transposition in maintaining high levels of flow throughout the entire occluded hemisphere was more marked compared to that resulting from the other methods, while the onset of ischaemic cerebral oedema was affected approximately at the same degree by all procedures. The results point to the role of the transposed omentum in providing an effective collateral circulation to the ischaemic brain.

Redundant nerve roots of the cauda equina

Four cases of redundant nerve roots of the cauda equina are reported, and the pertinent literature is reviewed. This disorder mainly affects males. The clinical history ranges from months to decades. The illness often starts with low back pain or sciatica, or both. Motor and sensory impairment of the legs dominate the further course of the disease. Serpentine filling defects in the column of contrast are a characteristic (but inconstant) feature on myelograms. Abatement of signs and symptoms occurs following adequate decompression of the redundant roots.

Angiomas of the cerebellopontine angle

Angiomas situated within the pontocerebellar cistern lie superficially on the ventrolateral aspect of the brain stem. Occasionally, minor extensions penetrate into the adjacent nervous structures. Five patients bearing such lesions were operated upon, using a microsurgical technique. Radical excision was performed in all cases. Within 2 to 12 months the patients had returned to their previous occupations, being fully able to work or attend school. There is increasing evidence for the effectiveness of surgical treatment of angiomas of the ventrolateral aspect of the brain stem and the cerebellopontine angle. The illness usually presents with hemorrhages of varying severity, ranging from mild to devastating. Impairment of consciousness, contralateral hemiparesis and ipsilateral cranial nerve palsies are the most frequent neurological signs after bleeding. The outcome following excision is primarily related to the preoperative condition. No additional deficits or only minor further impairment can be expected from surgical interference. Exploration is advisable whenever the malformation appears to lie on the surface rather than within the brain stem.

Surgical removal of striate arteriovenous malformations

Some arteriovenous malformations fed by the striate arteries and lying within the claustrolenticular region can be excised by using microsurgical techniques. Three patients operated on with successful removal of the malformation are discussed here.

Cerebral water and electrolytes in experimental ischaemia following omental transposition to the brain

Occlusion of the middle cerebral artery induces a local decrease in percentage of tissue dry weight in rabbit brain, associated with flux of sodium and potassium in reciprocal directions. Cortical swelling occurs also in remote non-ischaemic areas. Previous transposition of the omentum majus to the brain minimizes the onset of oedema consequent on occlusion of a major cerebral artery. Increasing experimental evidence points to the role of omental transposition in providing an effective source of collateral circulation, thus strongly affecting the threshold for infarction.

Aminoacid incorporation into polyribosomes of ischaemic and reperfused gerbil brain

Aminoacid incorporation into polyribosomes from the gerbil brain in a cellfree system is strongly affected by experimental ischaemia. Progression of the impairment of the protein synthesis in vitro occurs even following early reperfusion.

Effect of omental transposition to the brain on protein synthesis in experimental cerebral ischaemia

Occlusion of the middle cerebral artery severely affects the uptake of labelled leucine into various subcellular fractions from rabbit brain. Previous transposition of pedicled omentum to the cerebral surface maintains to a large extent the protein synthetic activity of the brain following arterial occlusion. The role of the transposed omentum in providing an effective collateral circulation and minimizing the occurrence of irreversible ischaemic lesions is stressed.

The subchoroid approach to the third ventricle

Surgical exposure of the third ventricle can be obtained by elevating the choroid plexus from the floor of the lateral ventricle and displacing it, together with the tela choroidea and the fornix. The operative technique for the subchoroidal approach to the third ventricle is reported.

Local cerebral blood flow after middle cerebral artery occlusion in rabbits following transposition of omentum to the brain

Transposition of pedicled omental grafts to the brain has been shown to minimize the effects of cerebral infarction in dogs and monkeys. An experimental study in which pedicled omental grafts and free non-revascularized omental grafts were placed on the brains of rabbits is reported. With the use of a modified inhaled hydrogen clearance technique to measure blood flow in the brain tissue, it was determined that the pedicled omental graft minimized the effects of middle cerebral artery occlusion by maintaining a collateral blood supply and limiting the decline of local cerebral flow. Super-position of free omental grafts on the brain had no effect on the threshold for infarction.

Surgical treatment of arteriovenous malformations of the posterior fossa

Nine cases of arteriovenous malformations of the posterior fossa were operated upon, using microsurgical techniques. The excision was radical in eight patients. Seven of them, as well as the sole patient who had a partial removal of the malformation, returned to their previous occupations without neurological signs. In one case the preoperative deficit was unchanged. Some lesions that appear to penetrate the brain stem actually lie on its surface and can be dissected through an extrapial plane of cleavage. Extension of the malformation into the cerebellar peduncles requires dissection of the tangle and opening of the IVth ventricle.

Effect of reperfusion on the uptake of [3H] uridine in the gerbil brain after prolonged ischaemia

The uptake of labelled uridine is reduced in the whole ischaemic hemispheres of gerbils subjected to unilateral carotid artery occlusion. Following circulatory restoration, brain structures that had an ischaemic insult of moderate intensity exhibit a progressively increased uptake. However, during reperfusion there is a tendency towards a clear cut definition of dead zones. This progression of the lesions seems to be related to a maturation phenomenon occurring in areas with an irreversible damage at the end of the ischaemic period.