Anatomical mapping of the cerebral nervi vasorum in the human brain

Cervical Ganglion Sympathectomy to Treat Cerebral Vasospasm in Subarachnoid Hemorrhage

Delayed cerebral ischemia (DCI) is still a significant cause of death and disability after aneurysmal subarachnoid hemorrhage. Cerebral vasospasm represents one of the most reported mechanisms associated with DCI. The management of DCI-related vasospasm remains a significant challenge for clinicians; induced hypertension, intraarterial vasodilators, and/or intracranial vessel angioplasty-particularly in refractory or recurrent cases-are the most used therapies. Because an essential role in the pathophysiology of cerebral vasospasm has been attributed to the adrenergic sympathetic nerves, a "sympatholytic" intervention, consisting of a temporary interruption of the sympathetic pathways using local anesthetics, has been advocated to minimize the vascular narrowing and reverse the consequences of cerebral vasospasm on tissue perfusion. In this review, we have analyzed the existing literature on the block of the cervical ganglions, particularly the stellate ganglion, in managing refractory cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage. These findings could help clinicians to understand the potential role of such intervention and to develop future interventional trials in this setting.

Innervation of the brain, intracerebral Schwann cells and intracerebral and intraventricular schwannomas

The cerebral vasculature and the choroid plexus are innervated by peripheral nerves. The anatomy of the vascular supply to the brain and its related perivascular nerves is reviewed. Intracerebral and intraventricular schwannomas most likely come from neoplastic transformation of Schwann cells investing the perivascular nerves and nerves within the choroid plexus.

The influence of noradrenergic blockade on vasospasm and the quantity of cerebral dopamine ß-hydroxylase following subarachnoid haemorrhage in rabbits

BACKGROUND

The aim of this study of experimental subarachnoid haemorrhage (SAH) and exclusion of the sympathetic nervous system (SNS) in rabbits was to find out if changes in the central noradrenergic areas of the hypothalamus and brain stem could be ascertained, in parallel with measurement of the intensity of chronic cerebral vasospasm in the basilar arteries.

METHODS

Histologic specimens were prepared by perfusion fixation on day 8 after the SAH. The spastic effect of experimentally induced SAH in New Zealand rabbits was investigated: firstly, using our previously developed method for measuring the corrugation coefficient (CC) of the vessel intima on precisely defined locations of the basilar artery (BA) with the aid of computer image analysis; and secondly, by immunohistochemical assessment of the concentration and localization of dopamine beta-hydroxylase (DBH), using anti-DBH, at precisely defined sites of the hypothalamus and brain stem of the same rabbit.

RESULTS

The intima of the BA, assessed by CC, was significantly less corrugated and had significantly less DBH in group A (the control group without SAH and without additional interventions; mean CC = 1.192, P = 0.004; median DBH = 0.50, P = 0.044), in group C (SAH and alpha-blocker phenoxybenzamine; mean CC = 1.142, P = 0.000; median DBH = 0.75, P = 0.001), and in group D (SAH and cervical gangliectomy; mean CC = 1.210, P = 0.003; median DBH = 0.50, P = 0.002) compared with group B (rabbits with SAH and without medication). Group B showed a significantly more intensive accumulation of DBH (median DBH = 1.15) and, according to the CC (mean CC = 1.369), more intensive corrugation of the intima of BA than all other groups. The correlation between CC and DBH for all the rabbits (groups A, B, C and D together) was significantly positive (Spearman Rho = 0.470; p = 0.010).

CONCLUSIONS

The results of this study demonstrated: firstly, an intensive excitatory influence of SAH on the quantity of DBH in central noradrenergic areas in the hypothalamus and brain stem; secondly, a very effective influence of peripheral and systemic sympathetic exclusion on lowering the quantity of central sympathetic DBH; thirdly, that the changes in the BA of individual rabbits occur simultaneously with corresponding changes in DBH-containing neurons, thus suggesting the likelihood of SNS involvement in the pathogenesis of post-SAH vasospasm in rabbits.

Predominant involvement of ipsilateral anterior and posterior circulations in moyamoya disease

BACKGROUND AND PURPOSE

We encountered several patients with childhood onset of moyamoya disease in whom the ipsilateral anterior and posterior circulations were predominantly involved. This study investigated whether this is an angiographic characteristic of this disease.

METHODS

We evaluated steno-occlusive lesions on angiograms of 85 patients with pediatric onset of moyamoya disease, using two 4-stage angiographic classification scales for the internal carotid artery and posterior cerebral artery systems (ICA and PCA staging, respectively) and determined whether lesions with more advanced ICA and PCA stages were on ipsilateral sides.

RESULTS

When positive laterality was defined as the presence of a difference by > or =1 stage between the stages on both sides, lateralities in the ICA stages and in the PCA stages were present in 40 (47%) and 27 patients (32%), respectively. Lesions with more advanced ICA and PCA stages were on the same side, with significant probability (P=0.024, Fisher's exact test). Lateralities in both ICA and PCA lesions were found in 17 patients. In 14 (82%) of the 17 patients, the more advanced side of ICA lesions was the same as that of PCA lesions, while it was contralateral in 3 patients (18%).

CONCLUSIONS

In pediatric-onset moyamoya disease, asymmetrical involvement of bilateral ICAs and PCAs was common, and the ipsilateral ICA and PCA tended to be predominantly involved.

Evaluation of functional response of cerebral arteries by a new morphometric technique

The contractile response of the rabbit basilar artery under four conditions was determined: (1) response in a resting condition without exclusion of the sympathetic nervous system (control group I); (2) response in a resting condition with alpha-adrenoceptor blockade (group II); (3) response to subarachnoid haemorrhage (SAH) (group III); and (4) response to SAH with alpha-adrenoceptor blockade (group IV). It was also ascertained whether it was possible to measure contractile response using a new morphometric method. Vessels were prepared by intracardial perfusion fixation, stained by haematoxylin and eosin, and the length of the intimal corrugations were measured by computer image analysis. Two procedures were followed in order to express the intensity of intimal corrugation, indicating the contractibility of the basilar arteries: (1) the corrugation coefficient (CC) of the basilar artery intima was estimated by dividing the precisely measured length of the intimal corrugations by the length of the measured vessel wall section of the vessel cross-sections (obtained histologically); (2) the lumen reduction coefficient (LRC) of the basilar artery was determined by dividing the "ideal" luminal area (calculated from the total length of the intimal circumference) by the real luminal cross-section area. The results of CC measurements revealed the smoothest intima (mean CC = 1.146, P = 0.00) and the least reduction of lumen (mean LRC = 0.26, P = 0.000) in group II (rabbits without SAH but with alpha-blocker phenoxybenzamine), and in group IV (SAH group of rabbits with alpha-blocker phenoxybenzamine) where the mean CC was 1.141 (P = 0.001) and the mean LRC was 0.33 (P = 0.002) in comparison with the SAH-only group III, pointing out the effectiveness of alpha-blockade even against SAH vasospastic stimuli. Control group I (without SAH and without treatment) showed a greater degree of corrugation in the intima and an increased reduction in the lumina than in groups II and IV, but still significantly less than in group III (mean CC = 1.197, P = 0.001, and mean LRC = 0.40, P = 0.028), thus demonstrating a certain resting tone of the basilar arteries (in an ideal situation, without any tone at all, the CC and LRC would be equal one). The highest degree of intimal corrugation and the greatest lumina reduction were discovered in the SAH-only group III (mean CC = 1.374 and mean LRC = 0.60). The differences among groups I, II and IV were insignificant. The results of this study suggest four conclusions: (i) the possibility of evaluating the functional response of rabbit cerebral arteries using this new morphometric technique; (ii) the adrenergic influence on resting tone of these arteries; (iii) the likely preventive role of an alpha-blockade on post-SAH vasospasm of basilar arteries in rabbits; and (iv) good comparability of the results of CC and LRC measurements with the angiographically estimated vessel diameters of other similar studies.

Cerebral blood flow in moyamoya disease. Part 2: Autoregulation and CO2 response

In order to clarify the cerebrovascular response in Moyamoya disease, the autoregulation and CO2 response was investigated using the 81mKr continuous cerebral blood flow (CBF) measurement technique. A total of 32 measurements were made over the anterior and posterior circulation in 16 Moyamoya patients (seven adults, nine children). CBF measurements were made during four loading trials (hypertension, hypotension, CO2 inhalation and hyperventilation). Study was then made of the vascular response of the frontal lobe, perfused by the internal carotid artery (ICA), and the occipital lobe and cerebellum, perfused by the vertebral artery (VA). Deficits of autoregulation were more severe among the juvenile cases in response to hypotension than to hypertension in both the ICA and VA regions, but the deficits were mild. The CO2 response to hypercapnea in the juvenile cases tended to be abnormal in both the ICA and VA regions. Both adult and juvenile patients showed deficits in the ICA region in response to hyperventilation, some of whom exhibited paradoxial responses. Notable differences in the severity of the deficits of the vascular response in adult and juvenile cases were seen, with the deficits in the response being more severe among the juvenile cases. Moreover, significant regional differences in the deficits were also found.

Contractile and relaxant responses of the canine isolated spinal artery to vasoactive substances

1. Effects of vasoactive substances were investigated in the canine isolated spinal branch of the intercostal artery (SBICA). 2. Addition of angiotensin II (AII), vasopressin, noradrenaline (NA), adrenaline, 5-hydroxytryptamine (5-HT), and dopamine each produced concentration-dependent contraction in the SBICA, whereas prostaglandin F2 alpha, histamine, and tyramine caused only slight contraction. The decreasing order of the potency of contractile agents was AII much greater than vasopressin = NA greater than 5-HT greater than adrenaline much greater than dopamine. 3. Although the pD2 value for phenylephrine (5.31 +/- 0.36) was smaller than that for NA (6.48 +/- 0.13), there was no significant difference in Emax value between these two agonists in the SBICA. On the other hand, xylazine produced only a slight contraction, the pD2 value being 3.59 +/- 0.08. Phentolamine (10(-8)-10(-6) M) and prazosin (10(-8)-10(-6) M) competitively inhibited the NA-induced contraction, while yohimbine (10(-8)-10(-6) M) did not. 4. Acetylcholine (ACh), sodium nitroprusside (SNP), ATP, ADP, and adenosine caused concentration-dependent relaxations in SBICA following contraction with NA. On the other hand, isoprenaline up to 10(-4) M did not produce any relaxation. The decreasing order of potency of the relaxant agents was ACh greater than SNP much greater than ATP = ADP = adenosine. 5. The ACh-induced relaxation was competitively inhibited by atropine and was abolished by mechanical removal of the endothelium. Aspirin (5 x 10(-5) M) did not affect the relaxant response to ACh, while oxyhaemoglobin (10(-5) M) and methylene blue (10(-5) M) produced significant attenuation. 6. These results suggest that NA produces contraction of the isolated canine SBICA which is mainly mediated via alpha 1-adrenoceptors and that ACh causes a relaxation of the SBICA due to release of endothelium-derived relaxing factor (EDRF) from the endothelial cells.

Concentrations of putative neurovascular transmitters in major cerebral arteries and small pial vessels of various species

The levels of noradrenaline, neuropeptide Y, 5-hydroxytryptamine, and substance P were measured and compared between the large arteries of the circle of Willis and the small cerebral vessels of the pia mater in the rat, rabbit, cat, and monkey. In all species, noradrenaline and neuropeptide Y concentrations were greater in the larger arteries than in small pial vessels. Noradrenaline concentrations were dramatically reduced following cervical sympathectomy, with the extent of diminution differing greatly in the various species; the effects of cervical ganglionectomy on neuropeptide Y concentrations were less pronounced. 5-Hydroxytryptamine concentrations in rats, cats, and rabbits were significantly greater in the small pial vessels, although measurable concentrations existed in the circle of Willis. In cats and monkeys, substance P was found in major arteries, but was not detectable at the level of the small pial vessels. The differences in the regional distribution of the various neurotransmitter candidates in the cerebrovascular bed may reflect their physiological significance.

Histochemical studies of the adrenergic innervation of canine cerebral arteries

The glyoxylic acid method was used to examine the adrenergic innervation of the major cerebral arteries of the circle of Willis in dogs. Fluorescent nerve fibers were observed in whole-mount preparations of the part of the internal carotid artery lying in the cavernosus sinus, the anterior, middle and posterior cerebral arteries, the posterior communicating artery and the basilar artery. Adrenergic nerve fibers were most abundant in the proximal portions of the anterior, middle and posterior cerebral arteries as well as in the posterior communicating artery. The distal smaller arteries were less densely innervated than larger ones. The basilar artery contained a moderate number of fluorescent fibers while the internal carotid artery lying in the cavernosus sinus had a very sparse innervation. The peak wavelengths of the excitation and emission spectra of the fluorescence were analyzed by means of a microepifluorescence spectrophotometer and were about 415 and 465 nm, respectively. These values suggest that the fluorescent fibers are adrenergic ones containing norepinephrine.

Bifrontal interhemispheric approach to aneurysms of the anterior communicating artery

The authors review their experience with the bifrontal interhemispheric approach in 603 cases of single anterior communicating artery (ACoA) aneurysms and describe the operative technique. With this approach, the olfactory tracts are dissected, and both A1 segments of the anterior cerebral arteries are identified subfrontally. The interhemispheric fissure is then dissected and A2 segments are followed from the distal portion toward the ACoA complex. Following the administration of a combination of mannitol, vitamin E, and dexamethasone, a temporary clip is placed on at least the dominant A1 segment prior to dissection of the aneurysm itself. Once the aneurysm has been completely freed from the surrounding structures, the neck is ligated and clipped. If the aneurysm ruptures during surgery, temporary clips are placed on both A1 and A2 segments bilaterally and the operation proceeds in a completely dry field. With this method, it is possible to occlude any of the intracranial vessels for up to 40 minutes within 100 minutes of drug administration. To prevent the possibility of rerupture and the development of vasospasm in the period before aneurysm surgery, the authors have adopted a policy of performing ultra-early operations within 48 hours of the onset of symptoms. Among the 257 cases operated on during the 9 years since 1975, one-fifth have been operated on within 48 hours of rupture, and the in-hospital mortality rate has been only 4.3% (11 cases). Follow-up studies have shown that 87% of the 246 surviving patients have returned to useful lives.

The relationship of free and conjugated catecholamines in plasma and cerebrospinal fluid in cerebral and meningeal disease

The concentration of free and conjugated norepinephrine (NE), epinephrine (E) and dopamine (DA) were measured by a modified radio-enzymatic assay in the plasma and in the cerebrospinal fluid (CSF) of 45 patients with normal and in 21 patients with disturbed blood-CSF barriers. In patients with an undisturbed blood-CSF barrier the free NE and E in CSF were 128 +/- 45 ng/l and 27 +/- 20 ng/l (mean values +/- S.E.), respectively, and represented about 50% of the average plasma values. Mean DA was not different in plasma (47 +/- 22 ng/l) and in CSF (41 +/- 19 ng/l). Both in plasma and in CSF, considerable higher free catecholamine (CA) levels were measured in patients with dysfunction of the blood-CSF barrier. In one patient with bacterial meningitis twofold higher concentrations of free NE and DA in CSF as compared with plasma were detectable. Sulfate conjugates of catecholamines are predominant in plasma and CSF. The contribution of conjugated CA to total CA in plasma from patients with normal blood-CSF barrier averaged 69.7%, 63.1% and 98.1% for NE, E and DA, respectively and was significantly lower in the CSF (p less than 0.001). In patients with disturbed blood-CSF barrier, the increases of conjugated CA were more pronounced in CSF than in plasma. Further, the contribution of conjugated NE and E to total NE and E in CSF was not only increased in patients with bacterial meningitis, but also in patients with renal insufficiency compared to the "control" patients (p less than 0.02 and p less than 0.001 resp.). Free and conjugated NE, E and DA in the plasma and CSF were related significantly (p less than 0.01 resp.) with stronger correlation for conjugated CA (p less than 0.001 resp.). These results together with findings in the literature, suggest that there is little or no rostral-caudal gradient in CSF CA conjugate concentrations and that even in patients with intact blood-CSF barrier plasma conjugated CA concentrations influence those in CSF. Thus only free CA levels in CSF may reflect the central adrenergic activity.

Innervation of brain intraparenchymal vessels in subhuman primates: ultrastructural observations

Sympathetic innervation of intraparenchymal blood vessels in the basal ganglia was demonstrated by transmission electron microscopy in arteries, arterioles, and capillaries of the subhuman primate brain. Small arteries (40-120 micron) and some arterioles (12-40 micron) are innervated only at branching sites. However, arterioles occasionally may be innervated at points distal to their origin. Capillary innervation was very infrequently observed.

Surgical treatment of middle cerebral artery aneurysms

The authors report their experience with the surgical therapy of middle cerebral artery (MCA) aneurysms in 413 cases, and describe their technique. After the M1 portion of the MCA is identified, the Sylvian fissure is opened. During the administration of 20% mannitol, temporary occluding clips are applied to the feeding and draining vessels of the aneurysm. The aneurysm is freed from all surrounding tissue, and the aneurysm neck is treated by ligation, clipping, or wrapping. Analysis of surgical results in 91 cases operated on after the surgical approach had become standardized indicates that more than 94% of patients have returned to useful social lives by the time of follow-up evaluation. Twenty-four percent of these patients were operated on within 48 hours after subarachnoid hemorrhage.

Trigeminal projections to supratentorial pial and dural blood vessels in cats demonstrated by horseradish peroxidase histochemistry

Anatomical and clinical observations suggest that supratentorial vascular structures contain afferent projections from the trigeminal ganglia. To characterize this innervation, horseradish peroxidase (HRP) and HRP conjugated to wheat germ agglutinin were applied to the pial and dural arteries and sinuses of 33 cats. HRP was restricted to the site of interest by applying it dissolved in a viscous polymer, polyvinyl alcohol (PVA), to achieve slow release and minimize diffusion. The ganglia of cranial nerves V, VII, IX, and X and the superior cervical ganglia (SCGs) were examined bilaterally for the presence of retrogradely transported protein. Horseradish peroxidase applied to the proximal middle cerebral artery was located in cell bodies occupying the portion of the ipsilateral trigeminal ganglion corresponding to the ophthalmic division and throughout both SCGs. When the tracer was applied to the right anterior or posterior superior sagittal sinus, HRP-positive cells were present as above, predominantly in the ipsilateral trigeminal ganglia corresponding to the ophthalmic division and throughout both SCG. When applied to the right middle meningeal artery, HRP was observed within neurons of ipsilateral SCG and in the ophthalmic division of trigeminal ganglia; a few enzyme-containing cells were present in ipsilateral regions corresponding to the second and third divisions. These observations support the concept that supratentorial vascular structures receive afferent nervous projections from trigeminal neurons.

Electron microscopic studies of ruptured arteries in hypertensive intracerebral hemorrhage

Eleven freshly removed brains and 20 lenticulostriate arteries (collected at emergency surgery for intracerebral hemorrhage) were examined by electron microscopy in a search for the mechanism of arterial rupture in hypertensive intracerebral hemorrhage. Forty-six of 48 ruptured arteries examined showed severe arteriosclerosis including degenerative changes of the media at or near bifurcations. Atrophy and fragmentation of smooth muscle cells gave them a moth-eaten appearance. Material resembling basement membrane and cell debris was also present in the arterial walls. The above findings were restricted to the middle and distal portions of the perforating arteries. Rupture from a miliary aneurysm was observed in only 2 of the 48 specimens examined. These resembled saccular aneurysms, ultrastructurally. They seemingly formed at a cavity which we strongly felt may have been formed by complete or incomplete subclinical hemorrhages; reabsorption of the hemorrhage from the dissection resulted in the aneurysms seen. Degeneration of smooth muscle cells may be the result of prolonged tension or spasm of the arterial wall as a result of longstanding hypertension.

Existence and localization of adrenergic neurons in meninges from human adults and fetuses

✓ The cerebral and cerebellar pia mater and arachnoid of 90 adults and 15 fetuses have been studied in order to determine whether the number of arachnoidal neural elements is sufficiently high to dismiss the possibility of their being purely heterotopic or displaced structures. With the aid of various histological techniques and formaldehyde (noradrenaline)-induced fluorescence, the presence of a reticulum composed of many short adrenergic neurons was demonstrated, intimately associated with the sympathetic perivascular innervation. Although this network seems to participate in some aspects of peripheral neuroendocrine function, its possible role in physiologically or pathologically regulating cerebral blood flow is as yet unsettled.

Effect of chronic sodium depletion on cerebrospinal fluid and plasma catecholamines

To test the role of central neurogenic factors in sodium-depleted states, cerebrospinal fluid (CSF) norepinephrine, epinephrine, and dopamine were measured in mongrel dogs first on a normal sodium intake (65 mEq sodium/day) and then on a 21-day regime of low sodium diet (4 mEq/day combined with diuretics). Plasma catecholamines were measured in the same group of dogs. Three weeks of sodium depletion supplemented with diuretics caused a 24-fold increase in plasma renin activity, hemoconcentration, and elevated serum protein concentration. Both plasma and CSF sodium decreased significantly. After sodium depletion, plasma norepinephrine rose 76% but epinephrine and dopamine did not change. The same pattern was observed whether samples were obtained in conscious or anesthetized animals. In CSF, norepinephrine rose 44% during sodium depletion, while epinephrine and dopamine remained unchanged. The CSF norepinephrine was related inversely to the CSF sodium concentration and directly to plasma renin activity. These observations support the view that the combined procedure of restricted dietary sodium intake and diuretic therapy causes alterations in CSF norepinephrine in a direction compatible with possible overactivity of central noradrenergic neurons.

Localization of adrenergic neurons in human and cat meninges

In human and cat meninges the presence of adrenergic neurons was studied. The human meninges were obtained from 10 adult individuals 1-3 hours postmortem and the 6 cats meninges, one pretreated 7 days before the experiment with 5 mg of 6-OHDopamine intracisternally. In human and cat meninges, adrenergic granulations, located in fibers that form a reticulum around the arterial, arteriolar and small vein vessels were observed. These adrenergic fibers appeared forming a very dense reticulum in the adventitia of the small calibre arteries and in arterioles. In addition, in some vascular sectors, a considerable number of triangular or elongated cells, whose cytoplasm is full of adrenergic granulations can be observed isolated or in close vicinity to the adrenergic reticulum. In the meninges of the cat treated with 6-OH-Dopamine there was no adrenergic granulation. Furthermore, the radioenzymatic determination of noradrenaline content in 3 human meninges shows the existence of this amine. The number of cellular elements with adrenergic granulations is notable and permits one to suspect that this cellular system can play an important role in the autoregulation on the cerebral circulation together with the perivascular adrenergic reticulum.

Correlation with superior cervical sympathetic ganglion and sympathetic nerve innervation of intracranial artery-electron microscopical studies

When the superior cervical ganglion was resected in dogs, nerve degeneration in arterial walls began after about 28 h and marked degenerative substance was shown after 40-48 h; after 4 days the small cored vesicles of adrenergic axons disappeared. The same condition was seen after 3 months, but after 6 months the small cored vesicles were again visible. When the middle cerebral artery was examined by separating it into the perforating artery near to the internal carotid artery and the peripheral portion of the middle cerebral artery, degeneration of the nerve fibers of the arterial walls occurred earlier in the more proximal portion. The distribution of adrenergic nerve fibers from the superior cervical ganglion is bilateral in the anterior cerebral artery from the anterior communicating artery to the peripheral region, basilar artery, and vertebral artery, but ipsilateral only in the anterior cerebral artery as far as the anterior communicating artery, middle cerebral artery, posterior communicating artery, posterior cerebral artery and superior cerebellar artery. Degeneration of nerve fibers of the walls of these cerebral arteries was not seen ever after stellate ganglionectomy in both sides.

Experimental cerebral vasospasm after subarachnoid hemorrhage. Participation of adrenergic nerves in cerebral vessel wall

Distribution and morphology of nerves in basilar-artery-induced vasospasm were investigated electronmicroscopically. Small cored vesicles were transformed, decreased and disappeared gradually after development of vasospasm induced by blood-CSF mixture incubated 5--10 days. These changes were not induced by fresh arterial blood, lysed platelets in saline and mechanical stimulation. In the portion with severe vasospasm induced by incubated blood-CSF mixture, nerve distribution was rich and uniform in all portions of the adventitia. In the portion with slight vasospasm, nerves were extremely scanty in the innermost area of the adventitia, within 10 mu from the outer edge of the media. The severity of experimental vasospasm became definitely lighter and the duration shorter after bilateral cervical sympathectomy. These findings indicate that nerves, especially the adrenergic axon in the innermost area of the adventitia, may play an important role on the genesis of late vasospasm. The difference in nerve distribution may be a factor influencing individual differences in frequency or severity of vasospasm.

Vasoconstriction of external carotid arteries after rupture of intracranial aneurysms

Vasoconstriction of the external carotid arteries, which has not been previously reported, was investigated angiographically in 23 patients who had intracranial vasospasm after aneurysm rupture. In about 50% of these patients vasoconstrictive change in the external carotid arteries was also found. These changes were not seen in control cases without intracranial vasospasm. Pathogenesis of the vasoconstriction of the external carotid arteries was discussed with particular emphasis on the relationship with sympathetic nerves.

Intercellular granules and vesicles in prolonged cerebral vasospasm

Prolonged vasospasm was produced in the dog basilar arteries by introduction of fresh arterial blood or norepinephrine into the chiasmatic cistern. Myonecrosis was limited to a small number of smooth-muscle cells, and a large number of muscle cells appeared intact. The most characteristic change was the appearance of aggregated granules and vesicles in the widened extracellular space between smooth-muscle cells, particularly near the adventitia and the elastic lamina. The granules were spherical, 50 to 100 nm in diameter, often surrounded by a single membrane, and contained a dense osmiophilic core, about 40 to 90 nm in diameter. In addition, the elastic lamina often became loose and corrugated or broken.

Non-penetrating trauma to the carotid artery with secondary thrombosis and embolism: treatment by thrombolysin

A case of partially occluding post-traumatic thrombosis of the internal carotid artery and secondary embolism of the middle cerebral artery is reported. The patient was treated with Thrombolysin with coincident resolution of clinical symptoms and signs and clearing of the lesions on arteriography. This may have been fortuitous. The subject of traumatic carotid artery thrombosis is reviewed in detail, and its pathophysiology is discussed, especially in relation to facts known about occlusive vascular disease secondary to atherosclerosis and related embolic phenomena. Suggestions are made concerning the treatment of this condition, especially with regard to developing rational criteria for opening vascular beds through evaluation of collateral cerebral blood flow. The uses of microvascular surgical techniques and thrombolytic therapy are considered.

Adrenergic blockade in subarachnoid haemorrhage

Over the last 15 years progressive interest has developed in the relationship between subarachnoid haemorrhage, sympathetic nervous system over-activity and the genesis of cerebral artery spasm. Following on from earlier work, vide infra, suggesting that adrenergic blockade might influence the course and prognosis of patients with subarachnoid haemorrhage, two double blind trials have recently been completed in Southampton. The first trial attempted to establish whether or not a single intracarotid injection of phenoxybenzamine improved the mortality and late morbidity of patients with subarachnoid haemorrhage. Results suggested that it did not. The second trial, comprising two groups of 50 patients each, attempted to assess the influence of prolonged treatment with propranolol on the course and prognosis of these subarachnoid haemorrhage patients. Early results suggest that, as with the alpha-blocker, the mortality and severe morbidity was not improved by beta-adrenergic blockade.