A novel missense mutation affecting the same amino acid as the recurrent PACS1 mutation in Schuurs-Hoeijmakers syndrome

A novel causative variant (c.608G>A, p.Arg203Gln) in PACS1.

Deletion of NKX2.1 gene encoding thyroid transcription factor-1 in two siblings with hypothyroidism and respiratory failure

Thyroid transcription factor-1 encoded by the NKX2.1 gene is a candidate regulator of thyroid and lung morphogenesis and function in humans. We report 2 female siblings with congenital thyroid dysfunction and recurrent acute respiratory distress carrying a heterozygous deletion of chromosome 14q12-13.3, resulting in haploinsufficiency for the NKX2.1 gene. This observation further supports a physiologic role for thyroid transcription factor-1 in early human thyroid and pulmonary function.

Growth hormone advances spermatogenesis in premature rats treated with gonadotropin-releasing hormone agonist

To clarify the effect of GH on the development of seminiferous tubules in premature male rats, we investigated whether GH accelerates spermatogenesis under the condition of gonadotropin deprivation. Male Wistar rats aged three weeks were divided into three groups and subjected to administration of either long-acting GnRH agonist (GnRHa) or a combination of GnRHa and rat GH, with normal saline solution as control. After the 4-week treatment, sperm density and motility in the right epididymis were measured and seminiferous tubules of right testes were histologically examined. Sperm density and motility were significantly higher in GnRHa+GH-treated rats than in GnRHa-treated rats. In histological examination, the numbers of germ cells in various stages were increased in GnRHa+GH-treated rats compared with GnRHa-treated rats, with the number of mature spermatid being noticeably higher in GnRHa+GH-treated rats. These results suggest that administration of GH decreases loss of germ cells at various stages of spermatogenesis under the condition of gonadotropin withdrawal.

Production of platelet-activating factor during focal cerebral ischemia and reperfusion in the rat

Platelet-activating factor (PAF) is a phospholipid mediator implicated in a diverse range of pathological processes. Beneficial effects of PAF antagonists have been shown in various models of central nervous system ischemia. In this study, we evaluated the production of PAF during focal cerebral ischemia and reperfusion in the rat. Ischemia was induced by occlusion of the middle cerebral artery with a thread. Quantification of PAF was performed with the radioimmunoassay technique. PAF was detected in the brain under normal conditions. Tissue PAF level in the ischemic cerebral hemisphere significantly decreased by prolonged ischemia (P<.05). Conversely, the decreased tissue PAF level during ischemia was significantly increased again by reperfusion (P<.05), but was still low compared with the control. This study indicates that the production of PAF in the brain tissue decreased by prolonged ischemia, and suggests the role of PAF in the reperfusion phase rather than during ischemia in the pathophysiology of ischemic brain injury.

Glucoregulatory disorders in school refusal students

OBJECTIVES

Our previous studies demonstrated autonomic nervous system disorders and cerebral blood hypoperfusion in school refusal students with underlying emotional distress due to fear or anxiety associated with school attendance. Because severe stress is known to affect glucoregulatory metabolism, this study used the oral glucose tolerance test (OGTT) to measure glucose metabolism in school refusal students.

DESIGN

A three-hour OGTT was performed. In preparation for the test, students fasted overnight. After a fasting blood sample was drawn, students were given solutions containing a predetermined amount of glucose based on their body weight (1.75 g/kg to a maximum 75 g). After glucose ingestion, blood samples were drawn at 30, 60, 90, 120, 150, and 180 mm to measure blood glucose (BG), immunoreactive insulin (IRI), pancreatic glucagon (IRG) and growth hormone (GH) levels. BG levels, IRI response, cumulative BG (sigma BG), cumulative IRI (sigma IRI), insulin/glucose ratio (delta IRI/delta BG), and insulinogenic index (sigma IRI/sigma BG) were then compared to previously reported normal control data. As an index of emotional difficulties, the self-rating depressive scale (SDS) was carried out.

PATIENTS

Eighty-one school refusal students (40 males and 41 females), 11-19 years of age (14.8 +/- 2.1), were studied. Their school refusal periods ranged from one month to eight years. All students were within -15 to +20% (-0.04 +/- 8.6) of ideal body weight.

MEASUREMENTS

BG levels were determined using a glucose oxidase reaction method. Serum hormones were measured by radioimmunoassay.

RESULTS

BG levels at all OGTT time intervals and sigma BG were significantly higher in school refusal students than the normal control data (sigma BG: 39.5 +/- 4.4 vs 33.3 +/- 3.4 mmol/l P < 0.001). Although the insulin response was abnormally low relative to the prevailing hyperglycaemia (sigma IRI/ sigma BG: subjects vs control = 232 +/- 129 vs 375 +/- 271, P < 0.01), normal beta cell secretory ability was speculated (sigma IRI: subjects vs controls = 2805 +/- 1274 vs 2523 +/- 1219 pmol/l). This suggests a relative suppression of insulin secretion. A paradoxical increase of GH was observed in 19 students after glucose ingestion.

CONCLUSIONS

Glucoregulatory disorders observed in school refusal students may be caused by emotional distress. Multiple factors including autonomic nervous system disorders, derangement of neuropeptides in the hypothalamus, and hormonal imbalances may also affect glucoregulatory metabolism, predisposing these students to hyperglycaemia. We speculate that the glucoregulatory system compensates for decreased blood flow to the brain by increasing blood glucose concentrations, thereby providing sufficient glucose as the primary energy source used during normal brain metabolism.

Glioblastoma multiforme in the left frontal lobe subsequent to malignant lymphoma in the right orbit

A 62-year-old male presented with glioblastoma multiforme in the left frontal lobe manifesting as motor aphasia, subsequent to a malignant lymphoma in the right orbit. He underwent subtotal removal of the right orbital mass presenting as right exophthalmos which was shown by histological examination to be non-Hodgkin's lymphoma. He received 30 Gy Lineac irradiation to the right orbit. His post-operative course was satisfactory. Magnetic resonance (MR) imaging with gadolinium-diethylenetriaminepenta-acetic acid (Gd-DTPA) 7 months later demonstrated a small spotty enhanced lesion in the left frontal lobe. He developed motor aphasia 1 year after irradiation. MR imaging disclosed an enhanced mass in the left frontal lobe, which was totally removed. Histological examination revealed glioblastoma multiforme. Patients with malignant lymphoma may develop a subsequent second malignant tumor. MR imaging with Gd-DTPA is quite useful for early detection of a second brain tumor.

[Role of arachidonic acid metabolites on development of ischemic cerebral edema in rat middle cerebral artery occlusion]

The products resulting from arachidonic acid metabolism of the both cyclo-oxygenase and lipoxygenase pathways possess strong physiological activities, such as vasoconstriction and the enhancement of vascular permeability. Therefore, it is likely that these metabolites are involved in cerebral circulatory disturbance and the formation of brain edema in cerebral ischemia. It is reported that intracerebral injection of leukotriene B4, C4, and E4 increased blood-brain barrier permeability. Thus, it is suggested that leukotrienes may induce vasogenic cerebral edema. We examined role of the products resulting from arachidonic acid of the cyclo-oxygenase and lipoxygenase pathways on the formation of ischemic cerebral edema in rats with focal cerebral ischemia. Focal cerebral ischemia was induced by the occlusion of right middle cerebral artery. Acyclo-oxygenase inhibitor, indomethacin (4mg/kg), was given intravenously 30 minutes before the occlusion of the middle cerebral artery. Also, azerastine hydrochloride (8mg/kg), which has an inhibitory effect on the production and release of leukotrienes from human neutrophil as well as an antagonistic action on leukotrienes and another inhibitory effect on the production of superoxide anion, was given intravenously 5 minutes prior to occlusion. Concentrations of prostaglandin E2 (PGE2), thromboxane B2 (TxB2), 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and leukotriene C4 (LTC4) measured by radioimmunoassay. The percent water content of a cerebral hemisphere was determined by the wet-dry weight method. In the occluded hemisphere, PGE2, 6-keto-PGF1 alpha, TxB2 and LTC4 significantly increased at 2, 6, 12 hours respectively, following the MCA occlusion as compared to the control levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Dopamine has inhibitory and accelerating effects on ischemia-induced neuronal cell damage in the rat striatum

Dopaminergic (DAergic) influence on ischemic neuronal cell damage in the dorsolateral striatum was studied. Intact and 6-hydroxydopamine (6-OHDA) lesioned rats, with and without pretreatment by D1 and D2 DA antagonists, were subjected to 20 min forebrain ischemia. Extracellular DA and glutamate (Glu) were measured using microdialysis technique. Histological examination was performed on the dorsolateral striatum and the hippocampal CA1 area 24 h after ischemia. DA increased 400-500 times the control level during ischemia among the groups except the 6-OHDA lesioned group. No significant changes were observed in the concentration of 3,4-dihydroxyphenylacetic acid (DOPAC), but a transient decrease was seen in homovanillic acid (HVA). Due to ischemia, Glu increased up to about 5 times the control level among the groups. Neuronal damage in the dorsolateral striatum was slightly attenuated by 6-OHDA lesion. Treatment by spiperone (D2 antagonist, 7 micrograms/kg IP) alone attenuated the damage strongly. Treatment by SCH23390 (D1 antagonist, 2.5 mg/kg IP) alone or both D1 and D2 antagonists had no effects. Data suggest that excessive Glu and DA are involved in neuronal cell damage. DA might enhance the damage via D2 but inhibit via D1 receptor.

Striatal grafts in infarct striatopallidum increase GABA release, reorganize GABAA receptor and improve water-maze learning in the rat

We grafted fetal striatal cells in ischemic rat models, and investigated graft survival/growth, GABA release, GABAA receptor reorganization and functional recovery. One hour intraluminal occlusion of the middle cerebral artery (MCA) induced ischemic infarct in the lateral part of the striatum and adjacent cortex. In ischemic rats, the acquisition of Morris' water-maze learning was significantly slower than that of control rats. In these animals GABA level in the globus pallidus, detected by microdialysis, was about the half of that of controls. However, after the grafts of fetal striatal cells in the striatopallidum, the acquisition was improved, thus no difference was observed in the time course of learning curves in control and grafted animals. GABA level recovered to almost normal level by the graft. It further increased by the treatment of a GABA uptake blocker (nipecotic acids) in the perfusion. In the grafts, GABAA receptor organization detected by autoradiography using [3H] labeled SR95531 was restored for more than 1 year after the graft. Data suggest that fetal striatal cell grafts in infarct striatum may partially reconstruct striatopallidal GABA projection and reorganize GABAA receptor. This might be a basis of improvement of function.

A phospholipase C inhibitor ameliorates postischemic neuronal damage in rats

BACKGROUND AND PURPOSE

The hypothesis of calcium-induced neuronal damage has been proposed regarding brain ischemia. Phospholipase C is an enzyme that catalyzes the phosphodiesteratic cleavage of phosphatidylinositol. The cleavage of phosphatidylinositol 4,5-bisphosphate by phospholipase C yields 1,4,5-inositol triphosphate, which mediates intracellular release of calcium, and 1,2-diacylglycerol, which is an activator of protein kinase C. We examined the effect of phenylmethylsulfonyl fluoride, a phospholipase C inhibitor, on delayed neuronal damage after transient forebrain ischemia in the hippocampal CA1 subfield in rats to assess the role of phospholipase C in postischemic neuronal damage.

METHODS

Twenty-minute forebrain ischemia was induced using the method of Pulsinelli and Brierley. We measured the neuronal density of the hippocampal CA1 subfield 7 days after reperfusion. The effect of phenylmethylsulfonyl fluoride was tested in both pretreatment and posttreatment groups.

RESULTS

In the vehicle treatment group (n = 13), neuronal density was 51 +/- 42/mm (mean +/- SD). The neuronal densities in the 50-mg/kg (n = 12) and 100-mg/kg (n = 14) phenylmethylsulfonyl fluoride pretreatment groups and the 100-mg/kg (n = 10) phenylmethylsulfonyl fluoride posttreatment group were 99 +/- 50, 150 +/- 55, and 143 +/- 63/mm, respectively. These values were significantly higher than that of the vehicle treatment group (p less than 0.05, p less than 0.01, and p less than 0.01, respectively).

CONCLUSIONS

It is suggested that the activation of phospholipase C has an important role in postischemic delayed neuronal damage.

[A case of extraneural metastasis of medulloblastoma successfully treated with cisplatin and etoposide]

A patient who had been treated for cerebellar medulloblastoma presented progressive abdominal distension and tachypnea. Metastases of the tumor in the abdominal and thoracic cavity were confirmed by cytology. The authors treated the metastasis with a combination of intravenous administration of 20 mg/m2/day cisplatin and 60 mg/m2/day etoposide for two 5-day cycles. After chemotherapy, the patient recovered fully with time and follow-up radiological studies demonstrated no evidence of tumor recurrence. Combination chemotherapy with cisplatin and etoposide is to be considered effective for extraneural metastasis of medulloblastoma.

Action of phospholipases A2 and C on free fatty acid release during complete ischemia in rat neocortex. Effect of phospholipase C inhibitor and N-methyl-D-aspartate antagonist

The levels of brain free fatty acids rapidly increase after the onset of ischemia. The purpose of this study was to investigate the action of phospholipases A2 and C during complete ischemia based on the effects of a phospholipase C inhibitor (phenylmethylsulfonyl fluoride) and the N-methyl-D-aspartate antagonist MK-801 on the release of free fatty acids in rat neocortex. Complete brain ischemia was induced in rats with cardiac arrest by intracardiac injection of KCl. Free fatty acid levels in the neocortex were measured 0, 2, 4, and 8 minutes after cardiac arrest. Phenylmethylsulfonyl fluoride inhibited the release of free fatty acids primarily from phosphatidylinositol during the first 2 minutes of ischemia and from phosphatidylcholine and phosphatidylethanolamine at 4 to 8 minutes of ischemia. Conversely, MK-801 inhibited free fatty acid release mainly from phosphatidylcholine and phosphatidylethanolamine at 2 to 4 minutes of ischemia. These results indicate that the release of free fatty acids during the first 2 minutes of ischemia can be attributed mostly to the action of phospholipase C, and that the activation of phospholipase C further influences the activation of phospholipase A2 in the subsequent course, while phospholipase A2 predominantly acts after 2 minutes of ischemia.

Atypical Moyamoya disease associated with brain tumor

A 4-year-old boy with right retinal hemorrhage, mental retardation, and multiple minor anomalies was referred to our hospital. Computed tomography scanning revealed a cystic brain tumor at the vermis. Angiography showed stenosis of both internal carotid arteries at the supraclinoid portion and the Moyamoya vessels. The right ophthalmic artery was dilated as wide as the internal carotid artery. Stenosis of the basilar artery was also observed. Collateral circulation via the posterior inferior cerebellar artery and Moyamoya vessels in the area of the posterior cerebral artery was observed.

[Effect of occlusion and reperfusion on free fatty acid levels and eicosanoid metabolism in a rat model of focal ischemia]

Focal brain ischemia was induced in rats by inserting a silicone rubber cylinder attached to a nylon surgical thread from the common carotid artery into the middle cerebral artery bifurcation. Reperfusion was achieved by removing the cylinder. In the ischemic area, free fatty acids were measured. Arachidonic acid lipoxygenase metabolites: leukotriene C4 (LTC4), and cyclooxygenase metabolites: thromboxane B2 (TXB2), prostaglandin E2 (PGE2) and 6-keto-prostaglandin-F1 alpha (6-keto-PGF1 alpha) were measured during ischemia and after reperfusion. There were five ischemia groups. The rats in these groups were killed 1, 2, 3, 4 or 6 hours after occlusion. In the reperfusion group, rats exposed to 1, 2, 3 and 4 hours of ischemia were killed 5, 4, 3 and 2 hours after reperfusion, respectively. The free fatty acids, which had increased due to occlusion, decreased after reperfusion from 1 hour of ischemia. With 2 or more hours of ischemia, however, the free fatty acids increased after reperfusion, indicating cell membrane destruction. Eicosanoids showed almost the same changes in all groups. The eicosanoid level was high only after 1 hour of ischemia and it stayed low if the ischemia time exceeded 2 hours and after reperfusion. Therefore, we suggested that eicosanoids are not a main cause of tissue damage in the ischemic area after 2 or more hours of ischemia.

Serum neuron-specific enolase levels after subarachnoid hemorrhage

We examined serum levels of neuron-specific enolase by enzyme immunoassay in 29 patients with subarachnoid hemorrhage due to ruptured cerebral aneurysm. Serum neuron-specific enolase levels were significantly higher in patients with a poor neurological status than in patients with a good neurological status on admission, and the greater the amount of subarachnoid blood, the higher the serum neuron-specific enolase level. Patients with a good outcome had low serum neuron-specific enolase levels throughout their courses. Serum neuron-specific enolase levels increased with development of delayed ischemic neurological deficits and, especially in poor outcome patients, high levels persisted until 3 weeks after the subarachnoid hemorrhage.

Cerebral blood flow after ventriculoperitoneal shunt in children with hydrocephalus

Fourteen hydrocephalic children were studied who were between the ages of 6 months and 14 years. Regional cerebral blood flow (rCBF) was measured by the 133Xe intravenous injection method after ventriculoperitoneal shunting. There was a negative correlation between slow flow and preoperative ventricular size (r = -0.718, P < 0.02), but there was no correlation between fast flow and preoperative ventricular size. There was also no correlation between rCBF and postoperative ventricular size. Postoperative IQ or development quotient showed a positive correlation with slow flow (r = 0.813, P < 0.01), but not with fast flow. It is suggested that in hydrocephalic children there is impairment of white-matter communicating fibres and secondary reduction in higher intellectual activity.

Role of brain tissue leukotriene in brain oedema following cerebral ischaemia: effect of a 5-lipoxygenase inhibitor, AA-861

It has been postulated that lipoxygenase metabolites of arachidonic acid play a role in the pathogenesis of cerebral ischaemia. Severe forebrain ischaemia in rats was induced by four-vessel occlusion with mild hypotension. After 30 min of ischaemia, circulation was restored by removing the arterial clamps and increasing blood pressure to preischaemic levels. During 30 min of cerebral ischaemia, free arachidonic acid increased by approximately 8.5 times compared with the preischaemic level. This accumulation was reversed within 60 min of reperfusion. The concentration of leukotriene C4 in brain tissue increased significantly during reperfusion: treatment with a 5-lipoxygenase inhibitor, AA-861, decreased the increase of brain water content associated with reperfusion. This study demonstrated that the increased arachidonic acid resulting from cerebral ischaemia in rats is metabolized to leukotrienes via the lipoxygenase pathway once circulation is restored, and these leukotrienes may play some role in the development of postischaemic cerebral oedema.

Changes in epidural pulse pressure in brain oedema following experimental focal ischaemia

This study was carried out to clarify the changes of pulse pressure of the intracranial pressure pulse wave in ischaemic brain oedema. Intracranial pressure and PP were measured in two groups of anaesthetized dogs; 1) increased volume of cerebrospinal fluid by cisternal saline injection (control group), 2) brain oedema caused by focal ischaemia (oedema group). Ischaemia was induced by 2 hours of occlusion of the anterior, middle cerebral and internal carotid arteries. The canine focal ischaemic model showed consistent ischaemic damage in the caudate nucleus and produced brain oedema successfully. PP increased linearly with rising ICP to 35 mm Hg, and PP in the oedema group was significantly smaller than that in the control group at the same ICP value. The slopes of the regression equation of ICP and PP were significantly different between the oedema and control group (oedema: 0.057 +/- 0.029, control: 0.106 +/- 0.009), mean +/- SD, P less than 0.005). These results suggest that PP is easily affected by ischaemic brain oedema, which indicates increase of the brain tissue in the cranium. We conclude that PP is affected even at the same ICP value when intracranial components have altered.

[Brain tissue leukotrienes in cerebral ischemia and the effect of inhibitor of SRS-A release on postischemic cerebral edema]

Arachidonic acid metabolites are postulated to play a role in the pathogenesis of cerebral ischemia. In order to test the development of lipoxygenase metabolites of arachidonic acid in cerebral ischemia, we measured free arachidonic acid and slow reacting substance of anaphylaxis (SRS-A) and leukotriene C4 in the brain tissue. Moreover, we studied the influence of inhibitor of SRS-A release on postischemic cerebral edema. Severe forebrain ischemia in rats was induced by the modification of the method described by Pulsinelli and Brierley. Both vertebral arteries were electrocauterized through the alar foramen and then bilateral common carotid arteries were clamped by aneurysmal clips and mean arterial pressure was reduced to 80-90 mmHg. EEG activity was isoelectric throughout the period of carotid clamping. After forebrain ischemia had been maintained for 30 minutes, recirculation was started by removal of the arterial clamps and by increasing blood pressure to the preischemic level. Following the desired ischemic or postischemic periods, the brains were frozen in situ with liquid nitrogen. The brains were then chiselled out during irrigation with liquid nitrogen and stored at -80 degrees C until analysis. The brain extracts were analysed by high performance liquid chromatography for free arachidonic acid, by bioassay using the ileum of guinea pig for SRS-A and by radioimmunoassay for leukotriene C4. Brain water content was calculated with dry weight method. Inhibitor of SRS-A release, tranilast, was given intraperitoneally, 100 mg/kg 30 minutes before induction of ischemia and 50 mg/kg immediately before recirculation.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effects of FO-1561 on postischemic cerebral functional and metabolic recovery in experimental cerebral ischemia]

Effects of S-adenosyl-L-methionine sulfate tosylate (FO-1561) on postischemic cerebral functional and metabolic recovery in experimental cerebral ischemia were investigated. Severe bilateral forebrain ischemia in rats was induced by four-vessel occlusion with reducing the mean arterial pressure to 100-110 mmHg. After forebrain ischemia had been maintained for 30 minutes, recirculation was started by removal of the arterial clamps of bilateral common carotid arteries and by increasing systemic arterial pressure to the preischemic level. The EEG was continuously recorded from gold-coated screws inserted bilaterally in the parietal bones with the tips in extradural position, against a reference inserted prefrontal bone. Analysis of power spectrum of EEG activity was done by Berg Fourier Analyser. The brains were frozen in situ with liquid nitrogen before, during and after ischemia and then chiselled out during irrigation with liquid nitrogen. Concentrations of ATP in brain tissue were determined with high performance liquid chromatography. FO-1561, 100 mg/kg, was given intravenously, immediately after recirculation. After recirculation there was a tendency that EEG power spectrum in FO-1561-treated animals contained higher percentage of beta wave compared to that in control animals, while delta wave was lesser in FO-1561-treated animals. At 90 minutes following recirculation, ATP level in control animals was 2.17 +/- 0.05 mumol/g (mean +/- SE) and 2.42 +/- 0.03 mumol/g (mean +/- SE) in FO-1561-treated animals. Thus, recovery of ATP level was significantly better in FO-1561-treated animals than in control animals (p less than 0.01).

Effect of nimodipine on cerebral functional and metabolic recovery following ischemia in the rat brain

Whether the calcium entry blocker, nimodipine, prevents the increase in the concentration of free fatty acids and metabolic disturbances during ischemia and promotes functional and metabolic recovery after recirculation were examined. Severe forebrain ischemia in rats was induced by four-vessel occlusion with mild hypotension. After 30 minutes of ischemia, recirculation was started by removal of the arterial clamps and by increasing blood pressure to the preischemic level. Recovery of EEG activity following recirculation was better in the nimodipine-treated group than in the control group. During the ischemic period, there were no significant differences in accumulation of free fatty acids or in depletion of ATP between treated and control groups. At 120 minutes following recirculation, recovery of the ATP level was significantly better in the treated group than in the control group. Therefore, the promotion of functional and metabolic recovery by nimodipine-treatment is suggested to be not due to the prevention of an accumulation of free fatty acids nor to the depletion of ATP during the ischemic period, but to either improvement of postischemic hypoperfusion or a direct action on metabolic processes during reperfusion period.

[Effect of calcium entry blocker, nimodipine, on the cerebral function and metabolic recovery following experimental cerebral ischemia]

Ischemic deporalization of cell membranes is associated with a precipitous influx of calcium from the extracellular to the intracellular compartment, and it is suggested that increased intracellular calcium in ischemic brain leads to an activation of phospholipase and to increase of the concentration of free fatty acids, in particular arachidonic acid, with energy depletion. The objective of the present study is to test whether calcium entry blocker, nimodipine, prevent increase of free fatty acids and metabolic disturbances during ischemic period, and promote functional and metabolic recovery after recirculation. Severe forebrain ischemia in rats was induced by four-vessel occlusion with reducing the systolic arterial pressure to 100 mmHg. After forebrain ischemia had been maintained for 30 minutes, recirculation was started by removal of the arterial clamps of bilateral common carotid arteries and by increasing systemic blood pressure to the preischemic level. The EEG was continuously recorded from gold-coated screws inserted bilaterally in the parietal bones with the tips in extradural position, against a reference inserted prefrontal bone. Analysis of power spectrum of EEG activity was done by Berg Fourier Analyser. The brain were frozen in situ with liquid nitrogen before, during and after ischemia and then chiselled out during irrigation with liquid nitrogen. Concentrations of ATP, ADP, AMP and free fatty acids in brain tissue were determined with high performance liquid chromatography. Nimodipine, 10 micrograms/kg, was given intravenously 2-3 minutes before induction of ischemia, and an infusion of 1 microgram/kg/min was continued during ischemic and postischemic periods.(ABSTRACT TRUNCATED AT 250 WORDS)

Models for studying long-term recovery following forebrain ischemia in the rat. 1. Circulatory and functional effects of 4-vessel occlusion

The article describes findings obtained by the application of the Pulsinelli-Brierley 4-vessel occlusion ischemic model in 2 rat strains. In one, a high incidence of respiratory arrest was observed after carotid occlusion. In the other, no such problems were encountered but a large fraction of the animals failed to lose consciousness upon arterial occlusion. In these "stuporous" animals, CBF values of major forebrain structures, as measured by a tissue sampling 14C-iodoantipyrine technique, showed considerable scatter with some values approaching 75% of control. However, even in animals which became comatose, flow was variable and occasionally approached 50% of control, the variability being especially pronounced in the hippocampus and the thalamus. It is concluded that the variability in ischemic flow rates must be taken into account when the model is used for studies of pathophysiological events and therapeutic interventions.

Intracellular pH in the brain following transient ischemia

The objective of the present study was to discover whether or not intracellular alkalosis develops in the brain in the recovery period following transient ischemia. Forebrain ischemia of 15-min duration was induced by four-vessel occlusion in rats, with recovery periods of 15, 60, and 180 min. Intracellular pH was derived both by the HCO3- -H2CO3 method and from the creatine kinase equilibrium. The ischemia was associated with energy failure and marked accumulation of lactic acid in the cerebral cortex. Recirculation brought about rapid rephosphorylation of adenine nucleotides and gradual normalization of lactic acid levels. After 15 min of recovery, the HCO3- -H2CO3 method indicated persisting acidosis, but the creatine kinase reaction did not. After 60 min, a shift of pH in the alkaline direction was demonstrated in both methods. This alkalosis had disappeared after 3 h of recovery. It is concluded that resumption of ATP production after ischemia is followed by a rapid rise in intracellular pH, which transiently increases above normal.

[Correlation between local cerebral blood flow and EEG in experimental cerebral ischemia]

Varying degrees of cerebral ischemia were produced in adult Wistar rats by clipping of bilateral common carotid arteries with or without induced hypotension. Local cerebral blood flow was measured from bilateral caudate nuclei and parietal cortices using the hydrogen clearance method. EEG was recorded from the same electrode as used for the hydrogen clearance method. The delta power of EEG increased along with decreasing local cerebral blood flow. There was an inverse correlation between the delta power of EEG and local CBF values, ranging from normal to extremely low (10 ml/100 g/min). When local CBF was reduced below 6-8 ml/100 g/min, EEG became isoelectric. Continuous EEG recording might contribute to predict rCBF value in the ischemic lesion.

[The role of sympathetic nerve and vasoactive amines in experimental cerebral vasospasm in dogs (author's transl)]

In order to study the role of sympathetic nervous system and vasoactive amines in cerebral arterial spasm, the following experiments were performed in dogs. In the first experiment, two weeks after bilateral removal of the superior cervical ganglion subarachnoid hemorrhage was produced by the puncture of the posterior communicating artery in six dogs. Second, the arterial blood of non-reserpinized dog was injected into the cisterna magna of another six reserpinized dogs. Diameter changes of the cerebral basal arteries before and after the experimental subarachnoid hemorrhage were observed utilizing the magnified vertebral angiography. Vasoconstriction 30 minutes after the puncture of the artery in the sympathectomized dogs was milder than that seen in the non-sympathectomized dogs, while vasoconstriction 24 hours after the subarachnoidal hemorrhage was induced similarly in degree in both groups. In reserpinized dogs, vasconstriction 30 minutes after the experimental subarachnoidal hemorrhage was somewhat milder than that seen in control dogs, and angiograms taken 24 hours after the hemorrhage showed that vasoconstriction was remarkably milder than in control dogs. Noradrenergic fluorescence of the arterial wall after the puncture of the posterior communicating artery was examined using Falck's fluorescence histochemical method. Noradrenergic fluorescence in the arterial wall did not disappear 15 minutes, 24 hours and three weeks after the experimental subarachnoid hemorrhage. From these experimental results, it was suggested that the sympathetic innervation to cerebral arteries might contribute to induce early spasm, but not to late spasm. Moreover, it was speculated that vasoactive amines released from the damaged brain tissue might play a role in inducing late spasm.

Spontaneous disappearance of a cerebral arteriovenous malformation in infancy. Case report

The authors report a case of the disappearance of an arteriovenous malformation in infancy, demostrated by follow-up angiography performed 7 months after the original angiograms. Some possible mechansims whereby a cerebral arteriovenous anomaly is thrombosed are discussed.

Experimental cerebral vasospasm. Part 2: effects of vasoactive drugs and sympathectomy on early and late spasm

The authors report the effects of vasoactive drugs and sympathectomy on experimental spasm using vertebral angiography. Papaverine and isoxsuprine injections into the vertebral artery released both early and late spasm. The antiserotonin agent, methysergide, adn the alpha adrenergic blocking agent, phentolamine, released early but not late spasm. In sympathathectomized dogs, early spasm was milder than in untreated dogs; however, late spasm was the same as in untreated dogs. The authors discuss an etiological difference between early and late spasm.

Experimental cerebral vasospasm. 1: Factors contributing to early spasm

✓The authors describe a model for making an experimental subarachnoid hemorrhage that closely simulates human aneurysmal rupture. A needle previously inserted into the posterior communicating artery is subsequently withdrawn by traction on a thread. Using this model they demonstrate biphasic spasm by measurement of cerebral blood flow and angiography after rupture of the artery; the early spasm lasted 60 minutes and the late spasm began 3 or 4 hours after subarachnoid hemorrhage and continued for several days. The authors discuss the pathogenesis of early and late spasm.