Ultrastructural cerebrovascular changes in a model of subarachnoid hemorrhage in baboon based on triple cisternal blood injection

In a subarachnoid hemorrhage model in the baboon, achieved through three cisternal blood injections with 1-day intervals, the cerebral arteries were dissected out 7 days after the first blood injection for electron microscopy All the animals showed ultrastructural changes in the cerebral arteries: two with severe, one with moderate, and three with mild alterations in the vessel walls. The most constant findings were seen in the muscle cells of the media layer. Fragmentation of the nuclei was frequently observed together with cytoplasmic vacuoles. Scattered groups or single degenerated muscle cells were also noted. In the intima the changes included rounding of the nuclei along with the appearance of cytoplasmic vacuoles. Desquamation or flattening of the endothelium and loss of tight junctions were encountered in some vessel areas. Degenerating mitochondria were a common finding.     

Sympathetic denervation accelerates wound contraction but delays reepithelialization in rats

Participation of the peripheral nervous system in wound healing is not well understood. The aim of this study was to investigate the effects of sympathetic denervation on rat excisional cutaneous wound healing. Male rats were chemically denervated with intraperitoneal administration of 6-hydroxydopamine (6-OHDA) in 1% ascorbic acid. 6-OHDA or vehicle was administered twice a week until euthanasia, beginning 7 days before wounding. A full-thickness excisional lesion was performed and the lesion area measured to evaluate wound contraction. After euthanasia, the lesion and adjacent normal skin were formalin-fixed and paraffin-embedded. Sections were stained with hematoxylin and eosin or toluidine blue, or immunostained for alpha-smooth muscle actin. Animals treated with 6-OHDA showed acceleration in wound contraction, increase in myofibroblastic differentiation, reduction in mast cell migration, and a delay in reepithelialization. To investigate the effects of neurogenic inflammation, a group of animals was treated with 6-OHDA only after the acute inflammatory phase, and these animals showed delayed wound contraction 3 and 7 days after wounding when compared to those treated before the lesion. In conclusion, the present study shows that sympathetic denervation affects cutaneous wound healing, probably by a decrease in neurogenic inflammation during the initial phase of healing and the absence of catecholamines throughout the final phase.     

Ultrastructural evidence of arterial denervation following experimental subarachnoid hemorrhage

Loss of catecholamine histofluorescence, increased sensitivity to norepinephrine, and changes in alpha1 receptor binding have led to the proposal that denervation hypersensitivity may play a role in cerebrovascular spasm. Because the significance of these alterations has remained unclear, the present study was undertaken to determine whether there was direct ultrastructural evidence of arterial denervation following experimental subarachnoid hemorrhage. Under general anesthesia, adult cats were subjected to pre-pontine injection of blood or serum (5 to 7 ml) via a transclival approach. The animals were sacrificed 4, 7, or 10 days later and basilar artery segments were prepared for electron microscopy. Control vessels appeared normal, whereas those bathed in blood revealed unequivocal changes in neural and supporting elements, including: 1) disintegration of both clear- and dense-core vesicles; 2) fragmentation of varicosities; 3) loss of Schwann cell cytoplasm; and 4) axonal degeneration. These changes were most pronounced 7 days after instillation of blood, and correlated in time with maximal injury of the media and endothelium. Although the development of smooth-muscle hypersensitivity remains unsettled, this study indicates that prolonged exposure to blood can cause extensive denervation of cerebral arteries.     

Etiology of the disruption in blood-arterial wall barrier following experimental subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage is associated with a sudden rise in intracranial pressure, acute arterial hypertension, and subarachnoid blood. The role that each of these factors may play in the development of the acute barrier disruption of the major cerebral arteries following subarachnoid hemorrhage was investigated in 42 rabbits. Horseradish peroxidase was given intravenously to assess the integrity of the barrier by transmission electron microscopy. Permeation of the tracer into the vessel was noted only in animals with increased intracranial pressure. A sudden rise in intracranial pressure is suggested to trigger acute barrier disruption following subarachnoid hemorrhage.     

Clinicopathological studies of three cases of cerebral aneurysms associated with systemic lupus erythematosus

We report three cases of ruptured cerebral aneurysms associated with systemic lupus erythematosus (SLE). A 52-year-old woman (case 1) with a fifteen-year history of systemic lupus erythematosus suddenly lost consciousness. She was admitted in a state of deep coma. A computed tomography (CT) scan revealed acute hydrocephalus and diffuse subarachnoid hemorrhage in the basal, interhemispheric and bilateral Sylvian cisterns. Fifteen years prior to this admission, cerebral angiograms demonstrated no cerebral aneurysm. She underwent ventricular drainage immediately. Postoperatively, her condition did not improve, and she died on the 18th day. During the autopsy, two saccular cerebral aneurysms were found: one aneurysm was at the right middle cerebral artery bifurcation, and another one was on the anterior communicating artery, which had disruption of the internal elastic lamina and medial smooth muscle, and infiltration of inflammatory cells. In the major cerebral arteries, for example the bilateral internal carotid arteries, disruption or dissection of the internal elastic lamina, intimal fibrosis and transmural infiltration of inflammatory cells were observed. The second patient, a 36-year-old woman with a six-year history of SLE, was admitted to our hospital with sudden severe headache. A CT scan showed subarachnoid hemorrhage, and cerebral angiograms disclosed saccular cerebral aneurysms on the anterior communicating artery and the left superior cerebellar artery, and a fusiform one on the left posterior cerebral artery. Surgery was not recommended because of her multiple medical problems. Her consciousness improved gradually over 2 months. She was transferred to the department of internal medicine for treatment of renal failure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Enzyme activities in granulation tissue: Energy for collagen synthesis.

Sympathectomy was produced in 8 dogs by the intravenous administration of 6-hydroxydopamine (6-OHDA). The animals were studied at rest and during exercise, prior to and after administration of the drug. The hemodynamic patterns observed during this experiment are similar to the previously reported patterns obtained after extensive surgical denervation or cardiac transplantation.     

Arterial wall changes in cerebral vasospasm

A right-sided subarachnoid hemorrhage (SAH) was created in 12 monkeys. Only the right (clot-side) cerebral arteries developed angiographic vasospasm (VSP), which was maximal 7 days after SAH. Eight animals were killed at this time and the remainder at 14 days. At the time of killing the middle cerebral arteries (MCAs) were harvested, and four normal, left (non-clot-side) MCAs were vasoconstricted in vitro with prostaglandin F2 alpha. All MCAs were studied with scanning and transmission electron microscopy. Right MCAs in maximal VSP 7 days from SAH were undistinguishable on scanning electron microscopy from normal arteries vasoconstricted in vitro: both groups demonstrated a mean 57% reduction in vessel caliber and a 5-fold increase in vessel wall thickness compared to normal, nonvasoconstricted left MCAs. On transmission electron microscopy, however, arteries in SAH-induced VSP showed degenerative changes in the tunica intima and media. These changes were still evident at 14 days, despite considerable resolution of VSP. These findings, as well as those from other pathological studies of animal and human cerebral arteries in VSP, suggest that the arterial narrowing and vessel wall thickening seen within several weeks of SAH is due primarily to medial contraction, but unlike simple vasoconstriction, is associated with degenerative ultrastructural changes in the endothelium and vascular smooth muscle cells which may denote a temporarily irreversible state.     

Mechanism of action of balloon angioplasty in cerebral vasospasm.

Recent technical advances in interventional neuroradiology have made it possible to dilate cerebral arteries showing vasospasm after a subarachnoid hemorrhage. Although the reported effects of dilatation in clinical cases have been dramatic, few experimental studies of the mechanism of action have been performed. It also is still unclear why dilated arteries rarely show restenosis. Using the scanning electron microscope, we examined changes in the three-dimensional structure of connective tissues in vessel walls after balloon angioplasty. Femoral arteries from cats and middle cerebral arteries from human autopsies were studied. The vessels were dilated in situ with a balloon catheter until the intimal pressure reached 1.5 Wr 3 atm; then they were fixed and digested with 88% formic acid. The specimens were freeze dried and observed under the scanning electron microscope. Normal vessels without balloon dilatation were treated in the same manner and used as controls. The results showed that the normal structure of collagen fibers in the vessel walls was affected significantly by balloon dilatation. Stretched and torn fibers were observed frequently when 3 atm were applied. We concluded that the long-lasting effects of balloon dilatation may be caused by the disruption of connective tissues that proliferate in the vessel wall after a subarachnoid hemorrhage.     

Disturbance in the intramural circulation of the major cerebro-pial arteries after experimental subarachnoid haemorrhage

The intramural fluid circulation of the cerebral arterial wall was investigated using horseradish peroxidase (HRP) as a tracer which was injected intravenously or intracisternally in dogs with or without subarachnoid haemorrhage (SAH). In the control dogs, the endothelial barrier function was confirmed for intravenous HRP, whereas the intracisternal HRP passed freely through the interstitial spaces of the adventitia and media to reach the intima within a few minutes. However, on the 5th day after SAH the barrier function of the intima for intravenous HRP was lost. In addition, there was a marked decrease in the amount of HRP reaching the intima when injected intracisternally. The intercellular space appears to be the main route for leakage of HRP into the subendothelial layer from the arterial lumen. Obstruction of the interstitial space in the adventitia by blood elements may be the cause of the disturbed intramural circulation of cerebrospinal fluid. These results suggest that this disturbance in the intramural circulation of the cerebral arterial wall plays a role in the development and/or progression of delayed cerebro-arterial narrowing after SAH.     

Brain and systemic temperature in patients with severe subarachnoid hemorrhage

BACKGROUND: The significance of brain temperature (BT) in patients with severe brain damage remains unclear. This study investigated the relationships between BT, systemic temperature (ST), and clinical outcome in patients with severe subarachnoid hemorrhage. METHODS: Thirty-one comatose patients with severe subarachnoid hemorrhage underwent ventricular drainage immediately after admission. The ventricular catheter also allowed monitoring of BT. ST was continuously measured using a bladder catheter with thermistor probe. RESULTS: BT at the start of the monitoring was lower than ST in four patients, and all died of brain swelling. BT was higher than ST at first but later fell below ST ("temperature reversal") in 12 patients, who all died of acute brain swelling. BT was higher than ST throughout the monitoring in 15 patients. Five of these patients died of causes other than brain swelling such as rerupture of the cerebral aneurysm, multiple organ failure, or respiratory failure. The other 10 patients survived with various degrees of disability. CONCLUSIONS: Observation of BT and ST can predict the outcome of severe subarachnoid hemorrhage.     

Significance of acute cerebral swelling in patients with sylvian hematoma due to ruptured middle cerebral artery aneurysm, and its management

A retrospective study of 75 patients treated surgically for ruptured middle cerebral artery (MCA) aneurysm within 48 hours evaluated clinical grade at admission, secondary development and management of cerebral swelling associated with space-occupying hematoma, cerebral infarction caused by vasospasm, development of hydrocephalus, and clinical outcome. Clinical grade at admission was significantly better in patients without than in those with hematoma (p < 0.01). Twenty-seven patients with sylvian hematoma caused by ruptured MCA aneurysm often developed ipsilateral cerebral swelling in the early period after subarachnoid hemorrhage. Seventeen of these patients developed serious cerebral swelling and received barbiturate therapy. Nine of these 17 patients had good outcome, but six patients died of cerebral swelling. The incidence of hydrocephalus was significantly higher in patients with than in those without hematoma (p < 0.01). The incidence of infarction was more pronounced in patients with sylvian hematoma. Clinical outcome was significantly better in patients without than in those with sylvian hematoma (p < 0.01). Development of cerebral swelling in patients with sylvian hematoma due to ruptured MCA aneurysm has a significant effect on outcome, and improvements in management are required.     

Cerebrovascular responses to subarachnoid blood and serotonin in the monkey.

Preliminary in vitro experiments were performed to determine the serum concentration of serotonin in the monkey, and the ability of cyproheptadine to block serotonin and serum-induced contractions in monkey cerebral arteries. Thirty-four cynomolgus monkeys were subsequently used to study changes in regional cerebral blood flow (CBF) obtained by the intracartoid 133Xe technique, and in the angiographic cerebral arterial caliber resulting from subarachnoid injection of artificial cerebrospinal fluid (CSF), blood, and serotonin. Five animals in each injection group were given 1.0 mg/kg intravenous cyproheptadine (a serotonin-blocking agent) during the post-injection period. Subarachnoid injection of artificial CSF produced no change in CBF or arterial caliber. Post-injection administration of cyproheptadine also had no effect on these parameters. A subarachnoid injection of fresh autogenous blood produced a significant but transient (less than 1 hour) decrease in CBF and moderate vasospasm, which lasted at least 3 hours. This vasospasm was essentially unaffected by intravenous cyproheptadine. The CBF and arterial caliber were unchanged following a subarachnoid injection of serotonin at concentrations (5 x 10(-6)M) present in normal monkey serum. In contrast, 5 x 10(-6) M serotonin invariably produced near maximal contractions in the in vitro cerebral artery preparations. Higher (x10) serotonin concentrations caused a transient CBF response similar to that obtained with blood. However, the cerebral vasospasm induced was of shorter duration than that obtained with blood. These results do not support a major role for serotonin in the production of post-subarachnoid hemorrhage vasospasm. Moreover, our data indicate that in vitro experiments do not reflect the ability of serotonin to constrict cerebral arteries in the intact animal.     

Cerebral arterial responses to induced hypertension following subarachnoid hemorrhage in the monkey.

Regional cerebral blood flow (rCBF), angiographic cerebral arterial caliber, and cerebrospinal fluid (CSF) pressure were measured in rhesus monkeys to determine the effect of experimentally induced subarachnoid hemorrhage (SAH) on cerebral arterial responses to graded increases in blood pressure. These measurements were also performed in a control group of monkeys subjected to a mock SAH by injection of artificial CSF into the cerebral space. Before subarachnoid injection of blood or artificial CSF, graded increases in mean arterial blood pressure (MABP) to a level 40% to 50% above baseline values had no effect on rCBF. The major cerebral arteries constricted and CSF pressure remained unchanged. Similar responses were observed after injections of artificial CSF. When MABP was increased in animals that had been subjected to subarachnoid injection of blood, rCBF increased and was associated with dilatation of the major cerebral arteries and moderate increases in CSF pressure. These results demonstrate that cerebral arterial responses to increases in blood pressure may be abnormal in the presence of subarachnoid blood. The manner in which abnormal cerebral arterial reactivity, changes in blood pressure, and vasospasm combine to determine the level of cerebral perfusion following SAH is postulated.     

不同部位骨骼肌失神经支配后超微结构变化的实验研究

目的：探讨长期失神经支配后萎缩骨骼肌神经修复手术疗效欠佳的机制。方法：12例臂丛神经损伤后1、2、3、6、12和18个月患者，术中切取小指展肌和肱二头肌的失神经骨骼肌，以相同部位的正常骨骼肌作对照，观察失神经骨骼肌超微结构和计数肌卫星细胞数量变化。结果：失神经支配后2个月，骨骼肌细胞的超微结构基本正常，肌纤维周围无明显增生的胶原纤维，可见到运动终板，肌卫星细胞数量多；6个月，肌丝断裂，排列紊乱现象明显增多，细胞核体积变小，染色加深，细胞核固缩，肌纤维周边出现较多的成纤维细胞和脂肪细胞以及增生的胶原纤维；12个月后，未见类似运动终板的结构，肌卫星细胞体积缩小，数量减少，小指展肌较肱二头肌中肌卫星细胞含量下降速度快。结论：失神经经支配晚期骨骼肌纤维中运动终板消失和胶原增生以及肌卫星细胞含量的迅速下降可能是影响疗效的主要因素之一。     

Haemodynamic,intracranial pressure and electrocardiographic changes following subarachnoid haemorrhage in rats

Summary Experimental induction of subarachnoid haemorrhage in rats resulted in acute haemodynamic changes. Heart rate decreased concomitantly with a rise in arterial blood pressure. Intracranial pressure increased and consequently cerebral perfusion pressure dropped. These changes as well as the observed electrocardiographic (ECG) changes were comparable to those reported in patients. Apart from blood also saline, when introduced into the cisterna magna, was able to elicit such abnormalities. The haemodynamic and electrocardiographic changes, which result from subarachnoid haemorrhage, may even become aggravated, when repetitive injections of blood or saline are given into the cisterna magna and when cerebral angiography is performed prior to induction of the subarachnoid haemorrhage. Chronic intracranial pressure monitoring during the 48 hours following subarachnoid haemorrhage revealed no significant rise in pressure.A thorough control of the experimental conditions is thus of utmost importance in order to give a valid interpretation of the observed anomalies.     

The experimental study of the cerebral vasospasm--the micro-circulation on the hypothalamus and the brain stem (author's transl)]

The correlation between the cerebral vasospasm and the micro-circulation in the hypothalamus and brainstem was observed histologically and electronmicroscopically using the colloidal carbon infusion method through the right vertebral artery of dogs. The posterior communicating artery of the dog was ruptured with a fine needle, which resulted in subarachnoid hemorrhage. The colloidall infusion was done at 30 min., 48 hours, 1 week and 4 weeks after the subarachnoid hemorrhage. Results 1) The cerebral vasospasm was confirmed by vertebral angiography on all cases with 30 min., 48 hours, and 1 week after the subarachnoid hemorrhage., In 1 case out of 5 with 4 weeks after subarachnoid hemorrhage vasospasm was also observed. 2) In the period of early spasm, ischemic changes were observed in the anterior-hypothalamus especially in periventricular area of the 3rd ventricle, and supraoptic nucleus. 3) In the period of late spasm, the ischemic changes in the hypothalamus became more conspicous, and these changes propagated into the tectal region of the midbrain and the central gray substance of the aqueduct. 4) In cases of 4 weeks after subarachnoid hemorrhage the ischemic change similar to cases listed in 3) was observed in 1 case whose angiography showed vasospasm. Another 4 cases showed no ischemic lesion at all. 5) Electron microscopic study showed the vasogenic edema in the hypothalamus in the case with cerebral vasospasm. There might be the possibility that vasomoter mechanism in the hypothalamus and brainstem would be involved with the vasogenic edema produced by cerebral vasospasm, which in turn would give a bad influence upon the spasmogenic vessels.     

Subarachnoid hemorrhage and circulatory disturbance of cerebrospinal fluid--scanning electron microscopid study in clinical and autopsy cases (author's transl)]

The scanning electron microscopy (SEM) gives intersting information about the changes of the subarachnoid space. In this study, specimens from 16 patients (one during surgery and others at autopsy) were examined by SEM: 11 cases of subarachnoid hemorrhage, 2 of posterior fossa brain tumor operated and 3 of control cases without CNS diseases. In cases of subarachnoid hemorrhage, there seemed to be three stages of the obstruction in the subarachnoid space: a) obstruction by blood clots mainly consisted of red blood cells, b) obstruction by subarachnoid fibrosis with thickening of arachnoid, c) obstruction by arachnoid adhesion obliterating subarachnoid space. Specimens from parietal parasagittal area, lateral cerebral fissure and temporal base on both sides were systematically examined by SEM, and the degree of the obstructive changes of the subarachnoid space were classified into five grades: 0) no changes 1) minimal changes--slight thickening of arachnoid and perivascular fibrosis in subarachnoid space 2) moderate changes--thickening of arachnoid and fibrosis in subarachnoid space with patent meshwork 3) severe obstruction of subarachnoid meshwork 4) complete obstruction of subarachnoid space--no space for CSF circulation. We found high incidence of communicating hydrocephalus after SAH in those cases in which epicortical CSF circulation was obstructed more than grade 3 in the parasagittal area bilaterally.     

The effect of sensory denervation on rabbits' knee joints. A light and electron microscopic study.

Unilateral sensory denervation of the hind limb in a group of rabbits caused progressive atrophy of cells in all structures of the knee joint, whether or not the joint was protected by a plaster cast. Immobilization without denervation caused proliferative changes, first in the synovium and then in the articular cartilage. The initial changes in the articular cartilage following sensory denervation occurred in the middle layers, suggesting that nutritional deficiency was involved. In contrast, the first changes in the cartilage of intact immobilized limbs occurred in the superficial layers and were most likely of mechanical origin.     

A role of the central catecholamine neuron in cerebral circulation

The effect of the central catecholaminergic neurons on the cerebral microcirculation was investigated by means of a unilateral intracerebral injection of 6-hydroxydopamine (6-OHDA) which produced the degeneration of catecholamine (CA) nerve terminals. Subsequent observation with CA histofluorescence revealed an absence of CA fibers in the vicinity of the 6-OHDA injection site. A significant increase in regional cerebral blood flow (rCBF), measured by the hydrogen clearance method, was demonstrated in the CA-depleted cortex under normocapnia as compared with rCBF in the control cortex (CA-depleted cortex 47.0 +/- 2.8 ml/100 gm/min; control cortex 38.5 +/- 3.5 ml/100 gm/min; p less than 0.005). The increased rCBF in the cortex treated with 6-OHDA was suppressed by the iontophoretic replacement of noradrenaline (NA) to the CA-depleted cortex. An iontophoretic replacement of 10(-5) M dopamine (DA) mildly suppressed the increased rCBF in the 6-OHDA-treated cortex. The CO2 reactivity in the CA-depleted cortex was significantly lower than that of the control cortex (CA-depleted cortex 2.13% +/- 0.6%/mm Hg; control cortex 3.53% +/- 0.70%/mm Hg). No change was noticeable in the cerebral glucose metabolism in the CA-depleted cortex in an investigation based on tritiated (3H)-deoxyglucose uptake. It is suggested that the 6-OHDA-induced change in cerebral blood flow (CBF) is not secondary to alterations in cerebral metabolic rate, and that the central NA neuron system innervating intraparenchymal blood vessels regulates CBF through a direct vasoconstrictive effect on the cerebral blood vessels. The central DA neuron system may modulate the cerebral circulation as a mild vasoconstrictor.     

The protective effect of experimental subarachnoid haemorrhage on sodium dehydrocholate-induced blood-brain barrier disruption

Summary The potential interactive effects between subarachnoid hemorrhage (SAH) and blood brain barrier (BBB) disruption were studied in a rat model. Experimental subarachnoid hemorrhage was produced in twenty rats (experimental group) by the intracisternal injection of blood. In ten additional rats (control group), saline was administered in place of blood. Analysis of mean blood pressure (MBP), intracranial pressure (ICP) and cerebral perfusion pressure (CPP) demonstrated an increase in ICP and MBP and a drop in CPP in all animals following intracisternal injection. Subsequent infusion of the left internal carotid artery with sodium dehydrocholate resulted in blood-brain barrier (BBB) disruption in both groups as evidenced by Evans blue staining of the infused cortex. The extent of BBB disruption was significantly greater in the control group than the experimental group.Analysis of the experimental group demonstrated that animals with the lowest pre-SAH MBP and the lowest CPP during the maximum blood pressure response to SAH demonstrated the greatest resistance to experimental BBB disruption.The possibility of ischemia as a contributing factor in BBB protection subsequent to SAH is discussed.