Biomedical subjects
Publications and source records attributed to C Testa.
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Low specific-activity scales consisting of alkaline earth metal carbonates and sulfates are often present in some gaseous and liquid hydrocarbon plants. These scales contain a certain concentration of radium, uranium, and thorium which can cause a risk of gamma irradiation and internal radiocontamination when they must be mechanically removed. The gamma dose rates and the 238U, 232Th, 226Ra concentrations were determined in sludges, scales, and waters of some gas and oil hydrocarbon plants located in Italy, Congo, and Tunisia. 238U and 232Th concentrations were were low. The isotopes 238U and 234U resulted in radioactive equilibrium, while 232Th and 228Th were not always equilibrium. A rough correlation was found between the gamma dose rate and the 226Ra concentration. Some considerations and conclusions about radiation protection problems are pointed out.
The appropriate time to perform surgery for posterior circulation aneurysms is debated. Controversy exists secondary to the lack of information regarding the overall management and outcome, as well as difficulties with their surgical treatment and infrequent occurrence. The present study examines the results of 46 patients with ruptured vertebro-basilar aneurysms treated with a delayed surgical protocol. Twenty-four were Hunt-Hess grade I/II on admission, 13 were grade III, and 9 grade IV/V. Nineteen patients (40%) (4 grade I/II, 6 grade III, and the 9 grade IV/V on admission) died before meeting the required conditions for surgery. Causes of death were vasospasm (8 cases), direct effect of the initial bleeding (7 cases), and rebleeding (4 cases). Surgical results were excellent/good in 87% of the patients. Surgical mortality was 8% (2 out of 24). In this study, despite encouraging surgical results, overall mortality was disappointingly high. We suggest that as more experience is gained in treating vertebrobasilar aneurysms, early surgery should be performed in selected cases. Early surgery is prophylactic for rebleeding and allows for more aggressive treatment of cerebral vasospasm.
Intact aneurysms of the carotid siphon at the point of take-off of the posterior communicating artery may exhibit orbital pain, whether associated with oculomotor palsy or not as a warning symptom prior to rupture. In order to explain this symptom the hypothesis of a sensory pathway within the third cranial nerve, which is liable to compression by the enlarging aneurysm sac, has been investigated. Data from human autopsy material show evidence of sensory ganglion cells within the rootlets of the oculomotor nerve; furthermore, studies in animals prove that the third nerve contains sensory fibers which run proximally along the nerve bundles, enter the brainstem and reach the spinal trigeminal nucleus. These fibers come from the ophthalmic division of the fifth nerve and join the third nerve at the level of the lateral wall of the cavernous sinus. Although a number of questions remain to be solved, the presence of a sensory pattern within the third nerve could account for fronto-orbital pain from enlarging aneurysms impinging on the third nerve itself.
We have examined the anticonvulsant properties of propofol in high doses in two experimental models of status epilepticus: generalized pentylenetetrazol (PTZ)-induced seizures and partial, cortically applied penicillin G-induced seizures. Propofol was administered either as a single bolus injection or as a bolus injection followed by an infusion for 1 h. When administered as a single bolus injection, propofol 12 mg kg-1 suppressed electrical and clinical seizures in PTZ generalized epileptic status, and an infusion of 50 mg kg-1 h-1 prevented the reappearance of electrical and clinical signs. In focal epileptic status, the single dose stopped paroxysmal activity and the associated clonic jerks for a few seconds. When the bolus dose was followed by an infusion, the firing bursts were replaced by isolated spikes, and contralateral jerks became sporadic and feeble. The greater efficacy of propofol against PTZ convulsions may be a reflection of the opposite action of the two drugs on neural membrane conductance: PTZ induces paroxysmal neural discharge by enhancing membrane conductance while propofol appears to decrease membrane conductance, thus suppressing paroxysmal discharge. There was no close relationship between blood concentration of the anaesthetic and its clinical effects, at least after a short-term infusion, as used in the present experiments. We suggest that propofol may be a potentially useful drug in status epilepticus in patients in whom benzodiazepines, barbiturates and phenytoin have failed.
Etiology and long-term prognosis were prospectively investigated in 155 consecutive patients (96 men and 59 women), aged 16 to 45 years, referred to our Neurosurgical Unit with cerebral transient ischemic attacks or infarction during the period 1978-1988. All patients underwent neurological and medical-cardiological evaluation, cerebral computerized tomography scanning, electrocardiogram, and laboratory tests. Two-dimensional echocardiography was performed in 123 cases (79%), cerebral angiography in 147 (95%). Atherosclerosis was the leading etiology occurring in 48 patients (31%). A cardioembolic disorder was considered the probable cause of ischemia in 8 cases (5.1%). Further possible etiologies were contraceptive pill assumption (5.8% of the total, but 15.3% within the female group), spontaneous arterial dissection (4.5%), migraine (4%), puerperium (2.6%), cervical trauma (2.6%), and other, more uncommon conditions. Despite extensive evaluation, the cause of cerebral ischemia remained unknown in 40% of cases. All patients received antiplatelet medication and 16 underwent surgery. The long-term outcome at a mean follow-up of 5.8 years was favorable: 91% of subjects resumed their work on a full or part-time basis.
Sixty-one consecutive patients, less than or equal to 40 years old, were hospitalized for cerebral infarction between 1977 and 1985. Evaluation included computed tomographic brain scan, arteriography, echocardiography, and blood tests. A probable migrainous infarction was diagnosed in six patients (10%) (all women with a history of migraine) who survived the initial stroke and were followed-up for an average of four years. In five patients the stroke occurred during a common migraine attack and in one patient during a classic migraine attack. The site of infarction was invariably the occipital lobe. During the follow-up, no subject had a further stroke. All six women had a permanent hemianopic deficit.
The results obtained in 304 consecutive patients with spontaneous subarachnoid hemorrhage are described, the majority of whom (86%) were admitted while in acute condition. Only 46% of the patients in this series were in good condition at admission. The initial management was standardized for all patients, but the protocol of "delayed surgery" was applied to patients with subarachnoid hemorrhage from aneurysmal rupture. Two hundred and twenty-two patients (73%) had intracranial aneurysms. Of these, 20 (9%) were moribund and died shortly after admission; nine (4%) underwent emergency surgery due to the coexistence of a life-threatening cerebral hematoma; seven (3%) were operated upon within 3 days of admission; 78 (35%) died after rebleeding or after steady deterioration of the patient's condition due to vasospasm while awaiting surgery. Of the remaining 108 patients ready for delayed surgery, 12 (11%) (operation refused, elderly patients in poor general condition, spontaneous thrombosis of the aneurysm) were treated conservatively, and 96 (89%), who were in various clinical conditions, were actually operated on. Of these 96 patients, 79 (82%) exhibited excellent or good results, 5 (5%) were disabled, and 12 (12%) died. In the authors' experience, the overall management of intracranial aneurysms in unselected patients according to the protocol of delayed surgery results in significant loss of patients awaiting surgery, and good surgical results in the survivors.
Two sisters harbouring an intracranial aneurysm are described. Rather than merely adding new cases to the records of familial aneurysms, this communication reports clinical and radiological findings supporting the hypothesis of inheritance: same anatomical location with involvement of the anterior communicating artery (ACoA), which is uncommon when dealing with familial aneurysms, and similar morphology of the lesions; identical haemodynamic pattern; similar timing of haemorrhage, occurring in both cases during the sixth decade.
The reduction of an intracranial arteriovenous malformation (AVM) by conventional radiation therapy is described in a patient who refused surgery. The 2-year follow-up angiogram documented nearly complete obliteration of the nidus of the AVM, accompanied by progressive narrowing of the arteries supplying the lesion. The scanty literature dealing with this form of treatment is summarized.
Seventy patients who had developed occlusion of the middle cerebral artery confirmed by angiography between 1970 and 1980 were followed up after an average of six years. Fourteen patients had died in the acute stage of the initial stroke. In the remaining 56 patients actuarial analysis showed that the observed incidence of survival for five years was 81.8% compared with an incidence of 94.1% in a matched normal population. Six patients sustained new strokes, four of which were ipsilateral to the middle cerebral artery occlusion. The observed cumulative incidence of subsequent strokes was 2% a year for the first five years of follow up. Twelve patients developed epileptic seizures.
Angiography is indispensable for the selection of appropriate candidates for extra-intracranial arterial bypass (E.I.A.B.). It allows the visualization of ICA and/or MCA occlusion or inaccessible stenosis which are considered indications for E.I.A.B. Complete angiographic study also gives information about other vascular lesions and the morphology of ECA and its branches as well as collateral circulation. Moreover angiography evaluates the result of bypass. The methods of the preoperative and postoperative angiography are described.
A technically adequate four-vessel cerebral angiogram was normal on the first day after a typical episode of subarachnoid hemorrhage. The study was repeated 40 days later showing a large aneurysm of the basilar bifurcation. Hypothetically, the first attempt to visualize the aneurysm was negative due to early transitory thrombosis of the aneurysmal sac. In some cases of subarachnoid hemorrhage it is beneficial to repeat previously normal angiographic studies.
Failure of unilateral carotid angiography to opacify a saccular aneurysm of the anterior communicating artery was observed; this occurred despite excellent visualization of the parent artery with spontaneous cross-filling and adequate demonstration of the intracranial carotid system bilaterally. In the absence of thrombosis of the aneurysm (which was discounted by contralateral carotid angiograms), vasospasm, and hypoplasia of the afferent arteries, a hemodynamic mechanism involving velocity of blood flow and intravascular turbulence is considered.
A giant fusiform aneurysm of the right middle cerebral artery was treated with extracranial-intracranial arterial bypass followed by controlled occlusion of the proximal parent artery using a Drake tourniquet. Thrombosis of the aneurysm is documented, with the distal extremity of the lesion being smoothly contrasted in a retrograde fashion by the hypertrophied bypass. The low risk as well as effectiveness of this combined approach to inaccessible intracranial aneurysms is confirmed.
Two cases of intracranial saccular aneurysm related to an arteriovenous malformation (AVM) are illustrated, in which a remarkable growth of the sac over the years was demonstrated angiographically. According to the relevant literature, aneurysm enlargement is correlated to the flow toward the AVM, increasing the intrasaccular turbulence and stress on the wall to which "solitary" aneurysms are usually subjected. The presence of bilateral infundibular widening at the origin of the posterior communicating artery is noted in one of the cases. This finding possibly confirms further the effects of hemodynamic stress.
The clinical course of 100 consecutive patients with angiographically proven carotid occlusion was reviewed. Ninety-three patients had been hospitalised for early stroke appropriate to the occlusion, and seven for transient ischaemic attacks. 68 patients were followed up from 1.5 to 5.9 years. The observed five year survival rate on an actuarial basis was 62.3%, compared to the expected rate of 90% in a matched normal population. The observed rate of recurrent stroke was 4.8% at 1 year. 12.2% at 3 years, 17.1% at 5 years. Among survivors, six patients (11.3%) developed seizures.