Percutaneous transluminal angioplasty for intracranial arteriosclerotic lesions

We report 17 cases of intracranial arterial stenosis treated by percutaneous transluminal angioplasty (PTA), including 9 on the intracranial internal carotid (ICA), 4 on the middle cerebral (MCA), and 4 on vertebrobasilar artery (VBA) system. All patients had ischaemic brain symptoms and stenoses of more than 60% (calculated angiographically). We treated four patients by PTA for residual stenoses after thrombolysis for acute occlusion. We used PTA balloon catheters 2.0-3.5 mm in diameter for all procedures. As a rule, the balloon was inflated for 1 min at 6 atm. All arteries were successfully dilated (stenosis less than 50%) except for one treated by PTA for residual MCA stenosis after thrombolysis. The patient died of a massive infarct due to MCA reocclusion caused by arterial dissection. Stenosis recurred in 4 of 16 patients. Repeat PTA was successfully carried out in these cases. However, stenosis recurred in one of these patients 3 months after PTA, but the patient is being followed because he is asymptomatic. PTA of intracranial arteries is effective, but its indications should be based strictly on potential risks, such as acute occlusion derived from arterial dissection.

Carotid endarterectomy and simultaneous percutaneous transluminal angioplasty for tandem internal carotid stenoses

We treated three patients with tandem internal carotid stenoses in single procedures including carotid endarterectomy (CEA) for the proximal stenosis and percutaneous transluminal angioplasty (PTA) for the distal stenosis. We devised a Y-shaped shunt tube for the CEA, through which a balloon catheter was introduced to perform PTA guided by mobile digital subtraction angiography. No cerebrovascular events occurred during follow-up. Our approach avoids the risk of a second procedure while effectively treating tandem stenoses.

Percutaneous Transluminal Angioplasty for Bilateral ICA Occlusive Lesions

SUMMARY

We performed Percutaneous Transluminal Angioplasty (PTA) in 50 patients with internal carotid artery (ICA) stenosis. Fifteen of these patients also showed signs of contralateral ICA occlusive lesions. Various neurological symptoms, such as hemiparesis or convulsions, frequently appeared in these patients with contralateral lesions during PTA. The balloon inflation time was restricted in 2 patients who experienced convulsions during PTA, resulting in an unsuccessful dilatation in one case. No permanent neurological deficits appeared as a result of PTA in these cases. The treatment for these cases is discussed in this report.

Endovascular Treatment for Tandem Internal Carotid Stenosis. Development of a New Shunt Tube for PTA

SUMMARY

Three patients with tandem internal carotid stenoses were treated in one operation including carotid endarterectomy (CEA) for the proximal stenosis and percutaneous transluminal angioplasty (PTA) for the distal stenosis. We devised a Y-shaped shunt tube which we used for CEA, while a PTA balloon catheter was introduced via the tube to perform PTA guided by portable digital subtraction angiography (DSA). No cerebrovascular events occurred during follow-up. Our approach avoids the risk of a second procedure while effectively treating tandem stenoses.

p16INK4 expression is associated with the increased sensitivity of human non-small cell lung cancer cells to DNA topoisomerase I inhibitors

Inactivation of p16INK4, an inhibitor of cyclin-dependent kinases 4 (CDK4) and 6 (CDK6), may be essential for oncogenesis in non-small cell lung cancer (NSCLC). We examined the sensitivity of two clones of p16INK4-transfected NSCLC cell line with homozygous deletion of p16INK4, A549/p16-1 and 2, to DNA topoisomerase I (topo I) inhibitors. A549/p16-1 and -2 showed 7.7- and 9.1-fold increases in sensitivity to CPT-11 (11,7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin ), respectively, compared with A549 cells. Ectopic p16INK4-expressing cells also showed approximately 4.0-fold increase in sensitivity to SN-38 (7-ethyl-10-hydroxycamptothecin), the active metabolite of CPT-11, compared to the parent cells. The topo I-mediated DNA relaxation activities of ectopic p16INK4-expressing cells were approximately 5 times higher than those of the parent cells. Northern and western blot analyses indicate that these increased topo I activities of ectopic p16INK4-expressing cells were due to an elevated topo I mRNA level and an increase in topo I protein. The chemosensitivity to topo I inhibitors, topo I mRNA level, protein content and activity of a p16INK4 revertant, lacking functional p16INK4, tended to be restored toward those of the parental phenotype to some extent. These results suggest that p16INK4 expression is closely associated with the increased sensitivity of ectopic p16INK4-expressing NSCLC cells to topo I inhibitors. The up-regulation of topo I mRNA level, protein content and activity may be responsible for this hypersensitivity.

Circumvention of glutathione-mediated mitomycin C resistance by a novel mitomycin C analogue, KW-2149

A novel antitumor antibiotic 7-N-[2-[[2-(gamma-L-glutamylamino)ethyl]dithio]ethyl] mitomycin C (KW-2149), an analogue of mitomycin C (MMC), is activated by thiol molecules, such as glutathione (GSH). To clarify the relationship between cellular GSH levels and the cytotoxicity of KW-2149, a murine fibroblast cell line (NIH/3T3) was transfected with human gamma-glutamylcysteine synthetase (gamma-GCS) cDNA, which codes a rate-limiting enzyme of GSH synthesis. Transfected cells (3T3/GCS) displayed increased gamma-GCS mRNA levels, gamma-GCS activity and GSH content, compared with NIH/3T3 cells. 3T3/GCS cells exhibited a 4.4-fold resistance to MMC, but not to KW-2149 (x 0.69), using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, suggesting that the increased cellular GSH levels did not affect the growth-inhibitory effect of KW-2149. KW-2149 exerted a greater growth-inhibitory effect than MMC on cisplatin- and doxorubicin-resistant cells with cross-resistance to MMC. KW-2149 exhibited a greater growth inhibitory effect than MMC not only on cells with GSH-mediated MMC resistance but also on cells with acquired resistance. We thus conclude that KW-2149 might be a clinically useful drug.

Subdural and meaningful involvement related to Wegener's granulomatosis: case report

OBJECTIVE AND IMPORTANCE

The first case of Wegener's granulomatosis associated with subdural empyema is presented.

CLINICAL PRESENTATION

A 37-year-old man was admitted to our hospital for treatment of bilateral subdural masses. Magnetic resonance imaging demonstrated strong bilateral subdural and meningeal enhancement. The patient was treated with subdural drainage, based on the diagnosis of bilateral subdural hematoma or empyema as revealed by magnetic resonance imaging. Even after surgery, he developed systemic symptoms that are typical for Wegener's granulomatosis, including hemosputum, papules, peripheral nervous disorders, hematuria, myalgia, and joint pain. A diagnosis of Wegener's granulomatosis was confirmed by positive circulating antineutrophil cytoplasmic antibodies and histological findings from the skin and nasal mucosa. We diagnosed the subdural masses as Wegener's granulomatosis from the laboratory and neuroimaging studies, retrospectively.

INTERVENTION

Pus-like fluid containing hematoma with negative micro-organism was evacuated by surgery.

CONCLUSION

Wegener's granulomatosis should be suspected in young patients with pulmonary symptoms and subdural hematoma without head injury. This is the first case of Wegener's granulomatosis associated with subdural masses.

Effect of glutathione depletion on cisplatin resistance in cancer cells transfected with the gamma-glutamylcysteine synthetase gene

Overexpression of the human gamma-glutamylcysteine (gamma-GCS) gene resulted in cisplatin resistance with an increased glutathione (GSH) content, increased ATP-dependent glutathione S-conjugate export pump (GS-X pump) activity and decreased platinum accumulation in human lung cancer cells transfected with a gamma-GCS cDNA expression vector, as we previously reported. In this study, we examined the effects of buthionine sulfoximine (BSO), a specific inhibitor of gamma-GCS, to determine whether GSH depletion alters cisplatin resistance in a gamma-GCS-transfected cell line, SBC-3/GCS. In the presence of 10 microM BSO for 4 days, SBC-3/GCS still showed resistance to cisplatin, although it was partially reversed. Under these conditions, GS-X pump activity remained up-regulated in spite of low GSH content, and the platinum content was decreased. These data suggest that the GS-X pump itself influences cisplatin resistance, as well as cellular GSH content.

The effect of endovascular therapy for cerebral arterial spasm, its limitation and pitfalls

PURPOSE

The effect of endovascular treatment for vasospasm was investigated by analysing the results of patients treated in Wakayama City in 1994.

MATERIALS AND METHODS

Ninety nine patients with ruptured cerebral aneurysms, who survived more than one week and were treated in Wakayama City in 1994, were studied. Twenty five patients caused symptomatic vasospasm and 25 were treated by endovascular therapy, percutaneous transluminal angioplasty (PTA) and/or intra-arterial papaverine infusion (IAP). PTA was performed for proximal vasospasm which located in the main arterial trunk, such as ICA, M1, BA (n = 3). IAP was chosen for distal vasospasm which located mainly in the M2, A1, A2 (n = 12). PTA and/or IAP was performed for diffuse vasospasm which located in proximal and distal arteries (n = 10).

RESULTS

In the proximal vasospasm group, all patients were good to moderately disabled on the Glasgow outcome scale (GOS). In the distal vasospasm group, 8 patients were good to moderately disabled, and 4 patients were severely disabled. The overall results were as follows: 17 (68%), good to moderately disabled, 4 (16%), severely disabled, 4 (16%), dead. The morbidity and mortality rate was 8/25 (32%) in symptomatic spasm group.

CONCLUSION

PTA was very effective especially for proximal vasospasm, but IAP was not always effective for distal or diffuse vasospasm. Diffuse vasospasm revealed a high mortality rate in spite of the endovascular therapy.

Antitumor effects of butyrolactone I, a selective cdc2 kinase inhibitor, on human lung cancer cell lines

Butyrolactone I, which is a naturally occurring specific inhibitor of the cdc2 kinase family, showed antitumor effects on several non-small- and small-cell-lung cancer cell lines with IC50 values the order of 50 micrograms/ml on the former. No cross-resistance of several drug-resistant cell lines, including those with the multidrug-resistant phenotype and five cisplatin-resistant cell lines to butyrolactone I was observed. The cdc2 kinase activity of PC-14 cells was inhibited by treatment with 20 micrograms/ml butyrolactone I, a concentration comparable to the IC50 value, for 2 hours. Longer exposure to butyrolactone I (> 24 hours) reduced the cdc2 kinase protein level. Butyrolactone I arrested the cells at the G2/M phase in a concentration dependent manner. These results suggest that butyrolactone I actually acts on cdc2 kinase, rather than other cdk kinases, in PC-14 cells. Inhibition of DNA synthesis, determined by measuring thymidine uptake, occurred earlier (2 hours) after initiating exposure than the decrease in the cdc2 protein level and was concentration dependent, suggesting that butyrolactone I inhibited DN4 synthesis. Cell permeabilization by digitonin enhanced DN4 synthesis inhibition by butyrolactone I, suggesting that the permeability of the membrane to this agent was the limiting factor for its growth inhibitory effect. Many anticancer agents, such as alkylating agents and cisplatin, cause cells to accumulate at the G2/M phase of the cell cycle. We investigated whether butyrolactone I had any modulatory effect on the antitumor effects of several anticancer drugs in vitro. Butyrolactone I showed no modulatory effects on vindesine, paclitaxel, or etoposide, but exposure of PC-9 and PC-14 cells to butyrolactone I together with or prior to treatment with cisplatin reduced the cytotoxicity of the latter. Thin-layer chromatographic analysis revealed that butyrolactone I bound to cisplatin, which was a possible cause of the reduced cisplatin cytotoxicity in the presence of bytyrolactone I.

Clinical use of mechanical detachable coils for dural arteriovenous fistula

Seven dural arteriovenous fistulas were successfully embolized with mechanical detachable coils. Two lesions were located in the transverse-sigmoid sinus, four in the cavernous sinus, and one in the marginal sinus. All lesions were completely occluded on postembolization angiography. No recurrent symptoms appeared during a mean follow-up period of 11 months. Owing to the length and retrievability of the mechanical detachable coils, embolization was quicker and safer, and coils were packed more densely, than is possible with conventional coils. Coil migration was avoided because coils of the appropriate size were chosen before they were placed.

Transluminal angioplasty for arteriosclerotic disease of the distal vertebral and basilar arteries

OBJECTIVE

Percutaneous transluminal angioplasty (PTA) for the distal vertebral and basilar artery is now being performed in selected patients with haemodynamically significant lesions of the posterior cerebral circulation. Its effect and overall results were examined.

PATIENTS AND METHODS

A balloon dilatation catheter specifically developed for these procedures, with a 2.0-3.5 mm balloon diameter, at 6 atmospheres of pressure, was used. Angioplasty was performed in 12 patients (including six whose initial results have been reported) with angiographically documented stenotic lesions involving either the intracranial vertebral artery (C1-C2 portion) or the basilar artery, and satisfying the following criteria: (1) clinical symptoms suggestive or consistent with a transient ischaemic attack refractory to medical treatment, or small infarction of the posterior circulation; and (2) angiographically documented stenosis greater than 70%. Two of 12 patients had complete thrombosis of the distal vertebral and basilar artery and PTA was performed after successful intra-arterial thrombolysis.

RESULTS

Successful results, without complications, were obtained in eight patients, with complete resolution of vertebrobasilar ischaemic symptoms. Immediate complications occurred in four patients including two with vessel dissection, and two with thromboembolism. The two patients with acute arterial dissection were reoperated but developed small infarctions with permanent neurological deficits. The two patients with thromboembolic complication showed transient neurological deficit. The overall stenosis ratio decreased from a mean of 84% pretreatment to 44% after the angioplasty procedure. Restenosis occurred in two patients. Long term clinical follow up in 11 patients who survived more than six months showed resolution of ischaemic symptoms after PTA in all except for one with a restenosis who had recurrent transient ischaemic attacks.

CONCLUSION

Transluminal angioplasty may be an effective procedure to treat vertebrobasilar ischaemia secondary to high grade arteriosclerotic disease affecting either the distal vertebral or basilar artery regions that do not respond to medical treatment.

Preoperative embolization of meningiomas fed by ophthalmic branch arteries

BACKGROUND

The efficacy of preoperative embolization for hypervascular meningiomas mainly fed by the branches of the ophthalmic arteries was examined.

CASES AND METHODS

Five hypervascular meningiomas mainly fed by the branches of the ophthalmic arteries, four posterior ethmoidal arteries, one anterior falx artery, and one recurrent middle meningeal artery were embolized with Gel-foam powder, polyvinyl alcohol (PVA) particles, and/or microcoils as a preoperative treatment using a microcatheter.

RESULTS

Catheterization of the ophthalmic and tumor feeding artery was possible and feeding arteries and lesion embolization were effective to reduce the bleeding during surgery in all cases. In three cases, visual acuity and visual field were preserved. However, in one case, visual acuity and visual field defect appeared due to the migration of Gelfoam powder (Upjohn, Kalamazoo, MI) into the retinal artery. In another case, the retinal artery was embolized with the feeding arteries since the patient was already blind.

CONCLUSION

Embolization of hypervascular meningioma feeding vessels arising from the ophthalmic artery is possible and effective with preservation of vision, if embolic agents are injected gently enough not to reflux into the central retinal artery.

[The effect on higher cortical dysfunction of percutaneous transluminal angioplasty for internal carotid artery stenosis]

Seven patients with internal carotid artery (ICA) stenosis with higher cortical dysfunction due to hemodynamic ischemia were treated by percutaneous transluminal angioplasty (PTA). The patients ranged from 49 to 71 years of age, and included five males and two females. Neuropsychological tests were evaluated before and after PTA. Higher cortical dysfunction improved in all cases after PTA. It is concluded that PTA is effective to improve higher cortical dysfunction in patients who have ICA stenosis associated with hemodynamic compromise, if the ICA is satisfactorily dilated.

Stenotic kinking of the cavernous internal carotid artery with a giant intra-cavernous aneurysm: case report

We report a giant aneurysm of the cavernous internal carotid artery with proximal internal carotid stenosis. The stenosis showed two typical features: a kink at the stenosis and location at the exit from the carotid canal. We believe that the cavernous portion of the internal carotid artery is compressed medially by the giant aneurysm and a kink occurs at the point where the artery leaves the bony carotid canal.

Tissue plasminogen activator thrombolysis and transluminal angioplasty in the treatment of basilar artery thrombosis: case report

A 61-year-old man with basilar artery thrombotic occlusion was successfully treated by a combination of local infusion of tissue plasminogen activator (t-PA) followed by percutaneous transluminal angioplasty (PTA). t-PA superselective infusion combined with the mechanical destruction of the clot by the guide wire was effective for recanalization. A Stealth dilation catheter, with a 2.5-mm balloon diameter and 10-mm length, was used for PTA. A balloon inflation time of 60 seconds with 4 atmospheres of pressure was delivered for successful dilation of the basilar artery. It was confirmed to be widely patent on follow-up angiography 40 days after the combined procedure with no further ischemic attacks apparent on clinical examination at 6 months.

[Newly developed blocking balloon catheter for PTA of internal carotid artery]

We have developed a new blocking balloon system for percutaneous transluminal angioplasty (PTA) of the internal carotid artery (ICA). A latex balloon (BALT) is attached on the top of a Superselector infusion-type catheter (TORAY) which is used as a blocking balloon catheter. It can be navigated into the distal part of the ICA under torque control as well as flow control by withdrawing the core wire. Our PTA procedure is as follows, 1) insert the sheath catheter 8-9 F in size, 2) insert the PTA balloon catheter (Accent balloon, Cook) with a blocking balloon catheter through the sheath catheter, 3) navigate the blocking balloon into the distal part of the ICA, 4) introduce the PTA balloon to the stenotic portion after occlusion of the distal ICA by the blocking balloon, 5) PTA, 6) wash the lumen of the ICA with saline, 7) deflate the blocking balloon and withdraw the system. We performed PTA for 5 ICA lesions in 4 cases and got successful dilatations for all of them without complications. Our blocking balloon system is useful for performing the PTA of the ICA safely.

Complex occipital arteriovenous fistula associated with neurofibromatosis treated by embolization and surgery. Case report

It is well known that neurofibromatosis is associated with various types of arteriovenous fistulas (AVF), but association with an occipital AVF has not been reported. We are reporting this case which was successfully treated with a combination of embolization and surgery. Superselective angiography defines the anatomic details of the fistula and intraoperative digital subtraction angiography (DSA) facilitates the surgery to cure the fistula. It is important to identify the best therapeutic options using angiographic information to treat a complex arteriovenous fistula.

Autotransplantation of peripheral cholinergic neurons into the brains of Alzheimer model rats

Current hypotheses regarding Alzheimer's disease implicate cholinergic function. In this study, peripheral cholinergic neurons in the vagal nodosal ganglion were transplanted into the brains of Alzheimer model rats. Eighteen Sprague-Dawley strain rats were divided into three groups: 1) unoperated control rats, 2) rats that had undergone bilateral destruction of the nucleus basalis of Meynert (NBM) (Alzheimer model), and 3) the transplantation group in which the vagal nodosal ganglion was transplanted into the cerebral neocortex one week after the bilateral destruction of the Meynert nucleus. Seven weeks after the transplantation rat behaviour was assessed using psychological tests (spontaneous activity, passive avoidance response and the Hebb-Williams maze test). The Alzheimer model rats had a statistically significant increase in spontaneous activity in comparison with controls (P less than 0.01). The transplant rats showed some amelioration of this abnormal increase in spontaneous activity observed in the Alzheimer model rats. All of the control rats showed conditioned passive avoidance responses, while only one Alzheimer model rat retained is shocked-conditions behaviour before 24 hours (P less than 0.01). Three of the six transplanted rats showed complete improvement in the passive avoidance response test. In the Hebb-Williams maze test, the rats with NMB lesions made more errors than the control rats. The transplanted rats had a lower number of errors than NBM-lesioned rats but still more than the controls. Histological examination revealed many cholinergic cells in the transplanted tissue, especially in the area adjacent to the cerebral cortical surface. The present results indicate that autotransplantation of peripheral cholinergic cells ameliorates abnormal behaviour in Alzheimer model rats.

Meningeal melanocytoma: magnetic resonance imaging characteristics and pathological features. Case report

A case of meningeal melanocytoma at the foramen magnum is reported in a 62-year-old man. Magnetic resonance (MR) imaging revealed characteristic signal patterns: homogeneous high intensity on the T1-weighted image and low intensity on the T2-weighted image. Light microscopy showed a histological appearance similar to that of melanotic meningioma. The ultrastructural features of the neoplastic cells were compatible with those of melanocytes, but they contained no features of arachnoidal cells. Immunohistochemical bromodeoxyuridine study revealed low proliferative activity among the neoplastic cells. The MR appearance and pathological features in this rare case of meningeal melanocytoma are demonstrated and discussed.

A possible involvement of central atrial natriuretic peptide in cerebral cortical microcirculation

The possible involvement of atrial natriuretic peptide (ANP) in cerebral cortical microcirculation was investigated in rats by means of laser-Doppler flowmetry and immunohistochemistry. In the laser-Doppler study, local cerebral blood flow (LCBF) changes after the administration of 10(-6) to 10(-8) mol/LANP solution or vehicle (saline solution) as an intracortical injection for 5 minutes were continuously monitored throughout the 30 minutes of the study and were expressed as percentages of preinjection values represented as 0%. The administration of 10(-6) to 10(-8) mol/LANP caused a significant decrease in LCBF; the onset of LCBF responses occurred within a few minutes after the start of the injection and the decrease in LCBF reached the maximum level within 7 to 10 minutes after the completion of the administration, after which LCBF gradually recovered. In the immunohistochemical study, no specific ANP immunoreactivity was found associated with the intraparenchymal blood vessels; however, ANP-immunoreactive neurons were observed primarily in the hypothalamus and septum, in which high concentrations of ANP-containing neurons have been identified. The data from the laser-Doppler study suggest that central ANP may produce a vasoconstriction of the intraparenchymal blood vessels, regardless of whether through direct action on these vessels or through the mediation by some system in the central nervous system. Because there is no evidence for ANP-containing nerves around these vessels, the role of central ANP in the cerebral circulation must await identification of the source of perivascular ANP.

[Selective vulnerability of peptide-containing neurons in cerebral ischemia; immunohistochemical study]

Histochemical changes in peptidergic and catecholaminergic neurons during ischemia were investigated in the cerebral neocortex of the gerbil. Catecholaminergic fibers were observed by catecholamine histofluorescence with glyoxylic acid solution, and peptidergic neuron systems such as vasoactive intestinal polypeptide (VIP), somatostatin (SOM), and neuropeptide Y (NPY) were observed by immunohistochemistry. Two hours after unilateral occlusion of the internal carotid artery, catecholaminergic fibers disappeared in the neocortex on the occlusion side, while peptidergic nerve fibers except for NPY fibers were intact after 2 hours of ischemia. NPY fibers had decreased in number on the occlusion side 2 hours after ischemia. VIP-, SOM-, and NPY-immunoreactive neurons showed a decrease of 60% six hours after ischemia, and these neurons completely disappeared in the cerebral neocortex 24 hours after ischemia. These results suggest that catecholaminergic neuron system is more vulnerable than the peptidergic one in ischemic event.

[Dynamics of extracellular acetylcholine of the gerbil striatum during cerebral ischemia monitored by intracerebral microdialysis]

Neurons in the hippocampus and striatum are vulnerable to the ischemic insult. In the present study we focused on the vulnerability of acetylcholine (ACh)-containing neurons in the striatum. To determine the change of ACh content in the striatum, we employed a simple sensitive brain microdialysis method with high performance liquid chromatography electrochemical detection. Morphological change of cholinergic neurons was studied by ACh-esterase staining during ischemic insult. After bilateral carotid artery occlusion, local cerebral flow decreased less than 5 ml/min/100 g in the striatum. Ach content in dialysate for 20 min after the occlusion was elevated to 135% of the control. ACh content decreased to 15% of the control 2hs after the ischemia. Density of Cholinergic fibers and cell bodies was reduced 10 min after the ischemia and further decreased 20 min after the occlusion. Our study suggests that the transient elevation of ACh content was probably due to diffusion of ACh from destruction cholinergic terminals after the ischemic insult. The increase of ACh immediately after arterial occlusion may affect severity of ischemic damage in the brain by its excitatory effect.

Effect of atrial natriuretic peptide on ischemic brain edema: changes in brain water and electrolytes

The effects of intraventricularly administered atrial natriuretic peptide (ANP) on the brain water, sodium, and potassium contents in ischemic brain edema were investigated. By use of a three-vessel occlusion model, ischemic brain edema was produced in the rat brain by 15 minutes of global ischemia followed by recirculation. Water content was measured by means of a drying/weighing method; sodium and potassium contents were measured by means of flame photometry. The effects of intraventricular administration of ANP were evaluated by a comparison between the groups given 2 and 5 micrograms of atriopeptin II (treated) and those given 0.9% NaCl (sham-treated). The treated groups showed significant decreases in brain water (P less than 0.02) and sodium (P less than 0.01) contents at 15 and 30 minutes after recirculation, whereas the brain potassium contents remained unaltered. Before ischemia and immediately after 15 minutes of ischemia, intraventricularly administered ANP did not significantly change the brain water, sodium, or potassium contents. There was no significant difference in the effect on the amount of brain water and sodium between the two doses (2 and 5 micrograms). These effects of ANP were thought not to be mediated by primary changes in serum osmolality and sodium and potassium concentrations, because intraventricular administration of ANP did not change them significantly. The present results reveal that, in ischemic brain edema, ANP may act directly on the central nervous system to inhibit brain water and sodium accumulation.