Diffuse cerebral ischemia in the cat: III. Neuropathological sequelae of severe ischemia

The neuropathological consequences of sever diffuse cerebral ischemia were investigated in an animal model in which postischemic alterations of regional brain blood flow and energy metabolism had been previously characterized. Pentobarbital-anesthetized cats received either 15 or 30 minutes of ischemia produced by basilar artery and bilateral carotid artery occlusions plus mild hypotension; this was followed by 60 to 90 minutes of normotensive recirculation. The brains were perfusion-fixed for light microscopy. Both insult durations resulted in unequivocal ischemic cell change affecting neurons of the cerebral neocortex, striatum, thalamus, and hippocampus and portions of the rostral brainstem. Animals with 30 minutes of prior ischemia differed from those with 15 minutes of ischemia in showing a more apparent regional accentuation of ischemic change in the parasagittal cortical gyri--the sites of previously documented focal postischemic heterogeneities of blood flow and metabolism. In other respects, however, the overall distribution and spectrum of severity of the ischemic alterations were similar for the two insult durations. These data support the view that significant permanent neuronal injury may result from a period of cerebral ischemia as brief as 15 minutes.

Computerised tomography after recent severe head injury in patients without acute intracranial haematoma

Sixty patients with severe head injury who did not have an acute intracranial haematoma on CAT scanning are reviewed. The scans are correlated with the level of consciousness at the time of scanning and with the outcome six months after injury. The initial scan was interpreted as being normal in 38% of the cases. In the remainder the most common abnormalities were small ventricles and areas of mixed increased and decreased density interpreted as contusions. All the patients with small ventricles were under 20 years of age. Postmortem examinations were undertaken on 15 of the 19 fatal cases. There was evidence of a high intracranial pressure in 12, cerebral contusions were absent or minimal in 10, there was diffuse immediate impact damage to white matter in six, and there was moderate or severe hypoxic damage in four.

Glial fibrillary acidic protein (GFAP): purification from human fibrillary astrocytoma, development and validation of a radioimmunoassay for GFAP-like immunoactivity

The extraction and purification of glial fibrillary acidic protein (GFAP) from human fibrillary cerebellar astrocytoma is described. Using an immunoperoxidase method, antisera raised to the protein showed specific staining of astrocytes in normal spinal cord and in tumours of astrocytic origin. A double antibody radioimmunoassay for GFAP in tissue extract was developed, the detection limit of the assay being 360 pg. Extracts of tissues other than brain or spinal cord did not cross-react significantly in the assay, neither did purified preparations of myelin basic and S-100 proteins. Levels of GFAP in normal CNS tissue were higest in spinal cord (1370 microgram/g wet weight) but a level of 3050 microgram/g wet weight was detected in a fibrillary astrocytoma.

Effects of increasing arterial pressure on cerebral blood flow in the baboon: influence of the sympathetic nervous system

The influence of stimulation of the cervical sympathetic chain on the response of cerebral blood flow to hypertension induced by the intravenous infusion of angiotensin was studied in anaesthetised baboons. Cerebral blood flow was measured by the intracarotid 133Xenon injection technique. Possible lesions of the blood-brain barrier were studied by injecting Evans blue towards the end of the experiment and ischaemic brain damage was assessed following perfusion fixation. In a control group of five baboons blood flow increased by 53 +/- 9% (mean +/- S.E.) from the base line values in the arterial pressure range 130-159 mm Hg. In four baboons subjected to unilateral sympathetic stimulation flow increased by 16 +/- 4% in the same pressure range. In three baboons subjected to bilateral sympathetic stimulation there were no significant increases in flow until the arterial pressure had increased above 159 mm Hg. Disruption of the blood-brain barrier in the parietooccipital regions was only seen in the control animals but not in the stimulated baboons. Ischaemic brain damage was not observed with the exception of one small lesion in a single stimulated baboon. These findings provide strong support for the observations of Bill and Linder (1976) that activation of the cervical sympathetic can modify the level at which breakthrough of cerebral blood flow occurs in association with systemic hypertension.

Brain damage complicating septic shock: acute haemorrhagic leucoencephalitis as a complication of the generalised Shwartzman reaction

The neuropathological findings in six patients who developed neurological signs after the onset of "septic shock" caused by Gram-negative septicaemia are described. The changes in the brains were characteristic of acute haemorrhagic leucoencephalitis, and there was evidence, particularly in the kidneys, of disseminated intravascular coagulation with tubular necrosis and, in some, appearances indistinguishable from membrano-proliferative glomerulonephritis. It is agreed that acute haemorrhagic leucoencephalitis is another manifestation of a generalised Shwartzman reaction, and it is suggested that activation of complement is the final common pathway that produces tissue damage in the brain and kidney.

Ischaemic brain damage in fatal non-missile head injuries

The incidence and distribution of ischaemic brain damage in a consecutive series of 151 patients who died as a result of a non-missile head injury in the Institute of Neurological Sciences was determined on the basis of a comprehensive neuropathological and neurohistological examination. Ischaemic damage was identified in 138 cases (91%) even after excluding cases who only had necrosis and infarction related to contusions or fat embolism, and infarction in the brain stem of the type conventionally associated with raised intracranial pressure. The ischaemic damage was assessed as severe in 37 (27%), moderately severe in 59 (43%) and mild in 42 (30%), and in the 138 cases with ischaemic brain damage it was found more frequently in the hippocampus (122 cases; 81%), and in the basal ganglia (119 cases; 79%) than in the cerebral cortex (70 cases; 46%) and in the cerebellum (67 cases; 44%). There were statistically significant correlations between ischaemic brain damage and either an episode of hypoxia or of raised intracranial pressure. From the nature of the brain damage it seems likely that much of it was due to a reduction in the cerebral perfusion pressure. This study has shown that ischaemic brain damage is common after head injury, that at least a proportion of it is probably avoidable, and that it is more important as a cause of mortality and morbidity after head injury than has been hitherto realised.

Remote metastases from intracranial tumours

A review of the primary tumours of the nervous system encountered over the past 16 years from the population of the west of Scotland uncovered only three tumours in which remote extracranial metastases had developed. In all three, there had been surgical intervention before the appearance of metastases. The findings in these patients are compared with those in other published accounts of this unusual complication.

Correlation between angiographic findings and the ischaemia of head injury

The carotid angiograms of 96 patients who had died from non-missile head injury were reviewed and assessed for evidence of arterial spasm, slowing of the cerebral circulation, and the presence of intracranial haemotoma. As bilateral angiography had been done in 44 cases the results are based on a correlation between the angiographic appearances and the presence or absence of ischaemic brain damage in the cortex of 140 cerebral hemispheres. There was a significant relationship between spasm alone, the presence of intracranial haematoma alone, or their combination, and ischaemic damage in the ipsilateral cortex. Apart from an association between the more severe grades of spasm and slowing of circulation in the group with ischaemia within arterial territories, there was none between slowing of the circulation or the combination of slowing with either spasm or haematoma and ischaemic brain damage.

Effects of hypotension induced by halothane, on the cerebral circulation in baboons with experimental renovascular hypertension

The effect of graded, progressive hypotension on the autoregulation of cerebral blood flow was studied in anaesthetized baboons with experimental renovascular hypertension. Graded hypotension was induced over a period of 5-6 h by the administration of increasing concentrations of halothane. In these chronically hypertensive animals cerebral blood flow remained constant until the mean arterial pressure had decreased to approximately 90 mm Hg. At mean arterial pressures of less than this value cerebral blood flow was pressure passive. At the completion of the investigation the brains were fixed by perfusion and submitted to neuropathological examination. Evidence of chronic hypertension and of ischaemic brain damage was found in every animal.

The smear technique in the diagnosis of neurosurgical biopsies

This paper reviews 216 consecutive neurosurgical biopsies examined by the immediate smear technique, and the smear diagnoses are compared with the final diagnoses made on paraffin processed sections of the same material. Ninety three percent (93%) of the diagnoses were correct. The majority of errors were due to the incorrect classification of malignant tumours. The diagnosis of malignancy, however, was clearly established in all of these cases. The smear technique is suitable for application to material obtained at craniectomy, laminectomy, and also the small, soft pieces of tissue obtained by needle biopsy through a burr hole.

Diffuse brain damage of immediate impact type. Its relationship to 'primary brain-stem damage' in head injury

In a neuropathological analysis of 151 fatal non-missile head injuries, there were 19 cases with focal lesions in the dorsolateral quadrant of the brain-stem in the corpus callosum, and histological evidence of diffuse damage to white matter. Eight of these cases had not experienced a high intracranial pressure during life. All 19 cases had been rendered unconscious at the moment of impact and had remained so or in the persistent vegetative state until death. It is therefore concluded that diffuse damage to white matter may occur as a primary event at the moment of impact, that is, it is one type of immediate impact damage to the brain. It is also concluded that this type of damage is the pathological basis of 'primary brain-stem injury' since in no patient thought clinically to have sustained 'primary brain-stem injury' were abnormalities confined to the brain-stem. Since no patient with this type of brain damage recovered consciousness after injury, it is probable that diffuse damage to white matter is the most important single factor governing the outcome in a patient who sustains a non-missile head injury.

Effects of dexamethasone and betamethasone on in vitro cultures from human astrocytoma

Cultures of human astrocytoma have been derived by collagenase digestion and are presumed, from their aneuploid karyotypes, to be predominantly neoplastic. Early passage cultures in proliferative phase have been cloned in the presence of dexamethasone and betamethasone, both commonly used in management of patients with brain tumours. These steroids raise both the cloning efficiency and the proliferative capacity of cells within each clone. Inhibition was detected only in very high steroid concentrations (25-50 microng/ml). Since these concentrations are unlikely to be attained in vivo it is concluded that anticipated physiological levels of these steroids enhance cell survival at low densities in culture. The significance of this in vivo is discussed.

Pathology of hypoxic brain damage in man

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Effects of acutely induced hypertension in cats on pial arteriolar caliber, local cerebral blood flow, and the blood-brain barrier

Acute hypertension was induced in 19 anesthetized cats by the intravenous administration of angiotensin. The caliber of pial arteries was measured by a television image-splitting technique and local cerebral blood flow by the hydrogen clearance technique. As the blood pressure was increased, pail arterioles constricted and cerebral blood flow remained relatively constant, showing that autoregulation of cerebral blood flow was intact. At mean arterial pressures of more than 170 mm Hg arteriolar dilation appeared. In smaller arterioles (initial diameter less than 100 mum) a segmental dilation (the "sausage'string" phenomenon) frequently preceded uniform dilation. This arteriolar dilation was associated with a marked increase in local cerebral blood flow indicating that the upper level of autoregulation had been breached. In no cat was vasospasm or a decrease in blood flow observed during induced hypertension. Hypertension also caused dysfunction of the bloodbrain barrier since, in 17 out of 19 of the cats examined, there was extravasation of protein-bound Evans blue into brain tissue. In only one of the 19 cats subjected to neuropathological analysis was ischemic brain damage identified and this was restricted to minimal ischemic cell change. The results indicate that severe, induced hypertension in cats produces cerebral arteriolar dilation, an increase of cerebral blood flow, and dysfunction of the blood-brain barrier. These observations may be of importance in understanding the pathogenesis of hypertensive encephalopathy.

Melanotic tumours (Blue Naevi) of spinal nerve roots

Four cases interpreted as intraspinal blue naevi are reported. The patients were adults females with an age range between 22 and 60 yr. In three there was a single tumour arising from the cervical posterior nerve roots and in the fourth there were multiple tumours arising from the posterior nerve roots of the spinal cord and occurring within the cerebello--pontine angle. The histological appearances of the tumours were similar in every way to those of dermal blue naevi. One was of the more common spindle-celled type and three of the cellular variant. The tumours contained melanin-pigment, and spindle cells with dendritic bipolar processes of the type described in dermal blue naevi. One was of the more common spindle-celled type and three of the cellular variant. The tumours contained melanin pigment, and spindle cells with dendritic bipolar processes of the type described in dermal blue naevi. Definite evidence of malignant tranformation was found in two cases and in a third, the appearances were suggestive for early malignant change. Therefore, unlike their dermal equivalents, intraspinal blue naevi appear to have a greater propensity for malignant transformation. In each case a careful clinical examination failed to reveal any evidence of a primary malignant melanoma. In the one case who died and on whom necropsy was performed, the failure to identify a primary cutaneous, mucosal or ocular melanoma substantiated our contention that these tumours were primary.

Triethyltin sulfate-induced neuropathy in rats. Electrophysiologic, morphologic, and biochemical studies

Adult rats given high orally administered doses of triethyltin (TET) sulfate lost weight, developed hind limb wasting, and became paraplegic or quadriplegic within three weeks of intoxication. A 33% reduction in the motor nerve conduction velocity (MNCV) of the sciatic nerve in the absence of significant demyelination was observed. There was observed, however, intramyelinic edema formation and an increased number of axonal neurofilaments and neurotubules; changes that paralleled the decrease in MNCV during the period of intoxication. Although the animals became asymptomatic and the MNCV normalized within two to three weeks of discontinuing the TET intoxication, the intramyelinic vacuoles and the increased numbers of neurofilaments and neurotubules persisted.

Core formation in the muscles of rats intoxicated with triethyltin sulfate

Young adult Osbourne-Mendel rats intoxicated for up to 23 days with triethyltin sulfate (TET) at a dose of 20 mg/liter of drinking water given ad libitum, developed core-like structures in type 1 extrafusal fibers of the soleus muscles. Frozen sections revealed an absence of oxidative enzyme activity (NADH-tetrazolium reductase) and diminished or absent myosin ATPase (pH 9.4) in the core regions. The main electron microscopic features within the cores were loss of mitochondria and streaming of the Z-disks. The histochemical and electron microscopic similarities and differences between the TET-induced cores, other core models, and those reported in some human neuromuscular disorders are discussed. The present experiments do not clarify whether the cores are produced from a direct effect of TET upon skeletal muscle or upon the neural component of the motor unit.

Alterations in behavior, brain electrical activity, cerebral blood flow, and intracranial pressure produced by triethyl tin sulfate induced cerebral edema

The interrelationships between cerebral edema, intracranial pressure (ICP), and cerebral blood flow (CBF) were studied in acute and chronic triethyl tin sulfate treated rats. Prior to pentobarbital anesthesia behavioral observations were made. ICP and regional CBF were measured under steady state conditions and brain water content was determined by vacuum drying of the right cerebral hemisphere. Control and chronic animals were neurologically normal. There were two distinct acute groups: (1) acute low pressure (ALP) animals - alert but tetraperetic, and (2) acute high pressure (AHP) animals - deeply stuporous, with minimal pain response and gross EEG slowing. ICP was significantly elevated only in AHP animals. Hemispheric CBF was significantly reduced in AHP and chronic animals. The interaction of increased pressure and edema (AHP) produced the greatest decrease in CBF, although deep white flows were significantly affected in all experimental groups. Chronic animals had significantly lower flow in four of seven regions compared to ALP animals despite no significant difference in ICP. Water content was significantly increased in all experimental groups with the greatest increase in the chronic animals. In the absence of any significant increase in ICP, cerebral edema appears to cause a significant reduction in cerebral blood flow and this reduction corresponds with the magnitude and location of the edema.

Experimental cerebral oligemia and ischemia produced by intracranial hypertension. Part 1: Pathophysiology, electroencephalography, cerebral blood flow, blood-brain barrier, and neurological function

Cerebral blood flow, electrical activity, and neurological function were studied in rabbits subjected to either 15 minutes of oligemia (20 torr cerebral perfusion pressure) or complete cerebral ischemia produced by cisterna magna infusion. During oligemia, flow was reduced from 68.4 +/- 4.2 ml/100 gm/min to 26.3 +/- 4.4 (p less than .01), and during ischemia animals had no proven flow. By 5 minutes after oligemia or ischemia significant symmetrical hyperemia occurred and there was no evidence of the no-reflow phenomenon. The electroencephalogram became isoelectric significantly later and returned significantly sooner in oligemia than in ischemia. Oligemic animals had earlier and better return of neurological function than their ischemic counterparts, although postinsult hypocapnia improved functional recovery in both groups. These experiments do not support the concept that oligemia is a more severe insult than complete ischemia. In intracranial hypertension produced by this model, the no-reflow phenomenon does not occur.

Experimental cerebral oligemia and ischemia produced by intracranial hypertension. Part 3: Brain energy metabolism

The authors studied the effect on cortical metabolites of intracranial hypertension produced by the infusion of mock cerebrospinal fluid into the cisterna magna in rabbits subjected to 15 minutes of cerebral oligemia (20 torr) or 15 minutes of complete ischemia. In both groups high-energy metabolites were exhausted within the first 5 minutes of the 15-minute insult. Significant recovery of the high-energy intermediates occurred within 15 minutes of reperfusion, well before return of electroencephalogram (EEG) activity. Continued reperfusion, during which electrical activity and function were returning, brought only moderate improvement in energy metabolites. In contrast, severe lactic acidosis persisted at least 15 minutes after insult, but was reduced by the time EEG activity returned. At no time were there striking differences in metabolites between the oligemic and ischemic groups. These results indicate that recovery in general, and the significantly earlier recovery of oligemic as compared to ischemic animals, cannot be explained on the basis of energy supply. Whether the persistence of lactic acidosis is an important factor limiting return of function requires further study.

The neurotoxic effects of triethyltin (TET) sulfate on myelinating cultures of mouse spinal cord

Well myelinated cultures of mouse spinal cord, exposed to varying concentrations of triethyltin sulfate, were examined at different time intervals by light and electron microscopy. At a high concentration of TET (10(-6)M) for 1-2 hours, the myelin sheaths and cells showed marked degenerative changes. At lower concentrations of TET (10(-7)-10(-9) M) intramyelinic and other types of vacuole formation were seen; however, these lesions were always accompanied by changes in the perikarya, dendrites and axons of neurons and in the astrocytes. Also, there was an apparent increased number of neurofilaments and neurotubules in many axons. The findings are discussed in relation to the lesions induced in the experimental animal by alkyl tin intoxication.

Experimental cerebral oligemia and ischemia produced by intracranial hypertension. Part 2: Brain morphology

The authors studied the morphological sequelae of 15 minutes of cerebral oligemia (20 torr cerebral perfusion pressure) and complete cerebral ischemia produced by raised intracranial pressure in rabbits. Ischemic cell change was present in five of seven ischemic animals; it was most extensive in the striatum and hippocampus, with only a few ischemic nerve cells in the thalamus and neocortex. The brains of control and oligemic animals were normal. These results indicate the following: 1) ischemia is a more severe insult than oligemia; 2) compression ischemia results in a pattern of damage that differs from that produced by other types of ischemia; and 3) the method used to reduce cerebral perfusion pressure is an important factor in determining the pattern and extent of brain damage produced.

Patients with head injury who talk and die

Of 66 patients with head injuries who had talked at some time after injury, 25% did not have intracranial haematoma at necropsy. Most of these had raised intracranial pressure (I.C.P.), and the commonest finding was local swelling related to contusions. Almost half of the non-haematoma cases had ischaemic or hypoxic brain damage, usually without contusions; 3 were children who had had status epilepticus. Fatality without raised I.C.P. was most often due to meningitis. In deteriorating patients without haematoma mortality and morbidity might be reduced by more diagnosis and treatment, particularly of raised I.C.P.

The undifferentiated and extended forms of C1300 murine neuroblastoma. An ultrastructural study and detection of concanavalin A binding sites on the plasma membrane

Mouse neuroblastoma cells (clone neuro-2A) in the undifferentiated and "differentiated" form were compared by light and electron microscopy. "Cytodifferentiation" was induced in monolayer cultures by the addition of dibutyryl-cyclic AMP. The pattern of concanavalin A binding sites was studied after coupling with horseradish peroxidase. The following major differences were observed. The differentiated cells are characterized by numerous and long neurites, aggregation of ribosomes into polysomes, an extensive network of neurofilaments and microtubules, many dense-core neurosecretory-like vesicles, a discontinuous pattern of concanavalin A binding sites on the plasma membrane, and an increase of the specific activities of acetylcholinesterase, choline acetylase and tyrosine hydroxylase. In contrast, the undifferentiated cells grown in suspension culture lack neurites, contain dispersed ribosomes, infrequent neurofilaments and microtubules and dense-core neurosecretory-like vesicles, and exhibit a continuous pattern of concanavalin A binding sites. In addition, the specific activities of the above mentioned enzymes are significantly lower.

Arterial spasm and slowing of the cerebral circulation in the ischaemia of head injury

Carotid angiograms of 33 patients who had died during 1968 and 1969 from blunt head injury were reviewed and assessed for evidence of arterial spasm and slowing of the cerebral circulation. Spasm was found in 57·5%, a prolonged circulation time in 57·5%, and a combination of both features in 42·4% of cases. In the same group of patients there was also a high incidence of ischaemic brain damage. There appeared to be some correlation between arterial spasm and ischaemic damage in the cerebral cortex, but none in the basal ganglia or in the white matter. There was no apparent correlation between a prolonged cerebral circulation time and ischaemic brain damage.

The histological accuracy of the smear technique for neurosurgical biopsies

✓ The preparation of smears from neurosurgical biopsy material is one technique by which a rapid diagnosis may be made available to the neurosurgeon. This technique is particularly appropriate for the small soft pieces of tissue obtained by needle biopsy. The 190 consecutive smear biopsies examined in this Institute during 1971 were reviewed and compared with subsequent paraffin sections of the same biopsies. In 94% of cases the correct diagnosis was obtained from the smears. Most of the errors stemmed from failure to distinguish between different types of malignant tumor. It is suggested that the smear technique is the most appropriate available for rapid neurosurgical diagnosis.

Fat embolism and cerebral infarction after use of methylmethacrylic cement

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Intradural spinal ossifying schwannoma. Case report

✓ A case of solitary intradural spinal ossifying schwannoma is presented in a patient whose symptoms and signs indicated a lesion at the level of the cauda equina.

"Idiopathic" thrombosis in the vertebrobasilar arterial system in young men

Two young men died as a result of cerebellar infarction due to thrombosis in the vertebrobasilar arterial system in the absence of atheromatous stenosis, other identifiable intrinsic arterial disease, or embolism. In each case the swollen cerebellar infarct had produced tonsillar herniation and hydrocephalus.

Effects of large doses of colistin sulphomethate sodium on renal function

High doses of colistin were used in the treatment of severely ill patients with refractory klebsiella chest and urinary tract infections. At the same time renal function was monitored to determine possible nephrotoxicity. In all patients it produced acute renal failure and in some acute tubular necrosis. Though renal failure contributed to the final cause of death in some cases, in the majority death was due to the primary neurological illness.

Acquired hepatocerebral degeneration: report of an atypical case

A case of acquired hepatocerebral degeneration secondary to biliary cirrhosis is described. It differs from the conventional type because of the clinical predominance of cerebellar symptomatology and because the principal neuropathological abnormalities were restricted to the pallidum and to the cerebellum.

Fat embolism

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