Neuroprotection by PlGF gene-modified human mesenchymal stem cells after cerebral ischaemia

Intravenous delivery of mesenchymal stem cells (MSCs) prepared from adult bone marrow reduces infarction size and ameliorates functional deficits in rat cerebral ischaemia models. Placental growth factor (PlGF) is angiogenic to impaired non-neural tissue. To test the hypothesis that PlGF contributes to the therapeutic benefits of MSC delivery in cerebral ischaemia, we compared the efficacy of systemic delivery of human MSCs (hMSCs) and hMSCs transfected with a fibre-mutant F/RGD adenovirus vector with a PlGF gene (PlGF-hMSCs). A permanent middle cerebral artery occlusion (MCAO) was induced by intraluminal vascular occlusion with a microfilament. hMSCs and PlGF-hMSCs were intravenously injected into the rats 3 h after MCAO. Lesion size was assessed at 3 and 6 h, and 1, 3, 4 and 7 days using MR imaging and histology. Functional outcome was assessed using the limb placement test and the treadmill stress test. Both hMSCs and PlGF-hMSCs reduced lesion volume, induced angiogenesis and elicited functional improvement compared with the control sham group, but the effect was greater in the PlGF-hMSC group. Enzyme-linked immunosorbent assay of the infarcted hemisphere revealed an increase in PlGF in both hMSC groups, but a greater increase in the PlGF-hMSC group. These data support the hypothesis that PlGF contributes to neuroprotection and angiogenesis in cerebral ischaemia, and cellular delivery of PlGF to the brain can be achieved by intravenous delivery of hMSCs.

Intravenous infusion of immortalized human mesenchymal stem cells protects against injury in a cerebral ischemia model in adult rat

Intravenous infusion of bone marrow cells has demonstrated therapeutic efficacy in animal models of cerebral ischemia and spinal cord injury. We intravenously delivered human mesenchymal stem cells (SH2+, SH3+, CD34-, and CD45-) immortalized with a human-telomerase gene (hTERT-MSCs) and transfected with eGFP or LacZ into rats 12 h after induction of transient middle cerebral artery occlusion (MCAO), to study their potential therapeutic benefit. hTERT-MSCs were delivered at 12 h after lesion induction. Lesion size was assessed using MR imaging and spectroscopy, and histological methods. Functional outcome was assessed using the Morris water maze and a treadmill test. Intravenous delivery of hTERT-MSCs reduced lesion volume and the magnitude of the reduction and functional improvement was positively correlated with the number of cells injected. The reduction of lesion size could be assessed in vivo with MRI and MRS and was correlated with subsequent histological examination of the brain. This work demonstrates that highly purified hTERT-MSCs reduce cerebral infarction volume and improve functional outcome.

Antitumor effect of genetically engineered mesenchymal stem cells in a rat glioma model

The prognosis of patients with malignant glioma is extremely poor, despite the extensive surgical treatment that they receive and recent improvements in adjuvant radio- and chemotherapy. In the present study, we propose the use of gene-modified mesenchymal stem cells (MSCs) as a new tool for gene therapy of malignant brain neoplasms. Primary MSCs isolated from Fischer 344 rats possessed excellent migratory ability and exerted inhibitory effects on the proliferation of 9L glioma cell in vitro. We also confirmed the migratory capacity of MSCs in vivo and showed that when they were inoculated into the contralateral hemisphere, they migrated towards 9L glioma cells through the corpus callosum. MSCs implanted directly into the tumor localized mainly at the border between the 9L tumor cells and normal brain parenchyma, and also infiltrated into the tumor bed. Intratumoral injection of MSCs caused significant inhibition of 9L tumor growth and increased the survival of 9L glioma-bearing rats. Gene-modification of MSCs by infection with an adenoviral vector encoding human interleukin-2 (IL-2) clearly augmented the antitumor effect and further prolonged the survival of tumor-bearing rats. Thus, gene therapy employing MSCs as a targeting vehicle would be promising as a new therapeutic approach for refractory brain tumor.

Differential gene expression screening between parental and highly metastatic pancreatic cancer variants using a DNA microarray

To clarify the difference in genes expressed in hematogenous metastasis and peritoneal dissemination, a broad analysis of differential gene expression analysis between parental cell lines and established metastatic sublines was performed. Using an oligonucleotide array (Gene Chip, Affymetrix), approximately 2,000 genes involved in cancer were analyzed for each of the cell lines. HPC-4H4 (highly metastatic lines to the liver) compared with HPC-4 (low metastatic parental lines), in which 20 overexpressed genes and 5 underexpressed genes were recognized. HPC-4P4a (highly metastatic to the peritoneum) compared with HPC-4, in which 12 overexpressed genes and 15 underexpressed genes were also recognized. Analysis of HPC-4H4 and HPC-4P4a showed comparative up-regulation of 20 genes and down-regulation of 13 in the former, HPC-4H4. Further studies are needed to validate our hypothesis that some of the resulting differentially expressed genes might be implicated in the development of metastasis in pancreatic cancer. In conclusion, this genome-wide expression analysis will help to clarify the molecular mechanisms of cancer metastasis and of the different levels of gene expression in a variety of metastatic potentials in pancreatic cancer.

Transplantation of clonal neural precursor cells derived from adult human brain establishes functional peripheral myelin in the rat spinal cord

We examined the myelin repair potential of transplanted neural precursor cells derived from the adult human brain from tissue removed during surgery. Sections of removed brain indicated that nestin-positive cells were found predominantly in the subventricular zone around the anterior horns of the lateral ventricle and in the dentate nucleus. Neurospheres were established and the nestin-positive cells were clonally expanded in EGF and bFGF. Upon mitogen withdrawal in vitro, the cells differentiated into neuron- and glia-like cells as distinguished by antigenic profiles; the majority of cells in culture showed neuronal and astrocytic properties with a small number of cells showing properties of oligodendrocytes and Schwann cells. When transplanted into the demyelinated adult rat spinal cord immediately upon mitogen withdrawal, the cells elicited extensive remyelination with a peripheral myelin pattern similar to Schwann cell myelination characterized by large cytoplasmic and nuclear regions, a basement membrane, and P0 immunoreactivity. The remyelinated axons conducted impulses at near normal conduction velocities. This suggests that a common neural progenitor cell for CNS and PNS previously described for embryonic neuroepithelial cells may be present in the adult human brain and that transplantation of these cells into the demyelinated spinal cord results in functional remyelination.

[A case of tentorial meningioma presented with pure word deafness]

It has been known that an isolation of Wernicke's area from auditory input results in pure word deafness. In this report, a 73-year-old female case with tentorial meningioma suffering from pure word deafness is reported. The patient initially presented with hydrocephalus, and was treated with a ventriculo-peritoneal(V-P) shunt. A year after the V-P shunt, she suffered from a symptom of deafness. On admission, her repetition and auditory comprehension were severely impaired, while reading and visual comprehension were almost normal. Auditory brain stem response(ABR) revealed normal latency between wave I and V, while wave VI and VII was disappeared. Middle latency response(MLR) showed no wave peak. On MRI, tentorial meningioma compressed bilateral medial geniculate bodies, but not auditory radiation or temporal lobe. 99mTc-HMPAO single photon emission computed tomography(SPECT) showed hypoperfusion in the left temporal lobe, considered as a diaschisis resulting from the isolation of left temporal lobe from auditory input via bilateral medial geniculate bodies.

[Characteristic improvement of the function following Schwann cell transplantation for demyelinated spinal cord]

Transplantation of Schwann cells (SCs) induced remyelination of demyelinated rat dorsal column (DC) axons and improved conduction. To investigate the difference between oligodendrocyte (OL) and SC myelination in conductive functions of axons, we compared normal DCs, demyelinated DCs, demyelinated DCs remyelinated by SC transplantation, and normal dorsal roots. All of the axons was originated from dorsal root ganglion neurons. Dorsal roots of adult rats were demyelinated at T11 by X-ray irradiation and ethidium bromide, and transplanted with SCs (3 x 10(4)) of adult rats. Three weeks later, the spinal cord was removed and pinned in a recording chamber and compound action potentials (CAPs) were recorded, to investigate conduction properties (conduction velocity and response after high frequency stimulation). Normal DCs or dorsal roots were recorded in same manner. Following transplantation of SCs, histological examination revealed SC-like patterns of remyelination in demyelinated DCs. SC transplantation improved significantly conduction properties compared to demyelinated axons, but less than normal DC. Moreover, remyelinated axons by SC transplantation showed as low amplitude of CAP as dorsal roots, but lower conduction velocity than dorsal roots. Though anatomical difference and/or time after transplantation influenced the conduction, these result suggested that SC myelination resulted in lower amplitude of CAP than OL, and SC remyelination might be insufficient for conduction velocity.

Excitability changes of dorsal root axons following nerve injury: implications for injury-induced changes in axonal Na(+) channels

Electrophysiological recordings were obtained from rat dorsal roots in a sucrose gap chamber to study changes in Na(+) currents following nerve injury. Application of 4-aminopyridine unmasks a prominent and well-characterized depolarization (delayed depolarization) following the action potential. In our previous studies, this potential, which is only present in cutaneous afferent axons, has been shown to correlate with activation of a slow Na(+) current. The delayed depolarization in the dorsal root was reduced 1 week after sciatic nerve ligation, suggesting a reduction in the kinetically slow Na(+) currents on dorsal root axons [control: 44. 2+/-7.3% (n=5); injury: 7.3+/-4.7% (n=5), P<0.001]. The refractory period of the action potential was reduced following nerve injury, in agreement with biophysical studies indicating faster "repriming" of fast Na(+) currents on cutaneous afferent cell bodies. Dorsal root ligation near the spinal cord also results in a reduction in the delayed depolarization. These results indicate that changes in Na(+) channel organization occur on dorsal root axons following either central or peripheral target disconnection, suggesting trophic support can be derived from either the CNS or the PNS.

The delayed depolarization in rat cutaneous afferent axons is reduced following nerve transection and ligation, but not crush: implications for injury-induced axonal Na+ channel reorganization

Two distinct populations of Na+ channels (kinetically fast and slow) are present on the cell bodies and axons of cutaneous afferent neurons; the fast current is increased and the slow current reduced in amplitude following nerve injury. The present study was undertaken to determine if similar changes occur on the axons of these neurons following peripheral nerve injury. The compound action potentials from rat sural nerves were recorded in a sucrose gap chamber. Following application of 4-aminopyridine, a prominent and well-characterized depolarization (the delayed depolarization) followed the action potential. This potential, only present on cutaneous afferent axons, has been correlated with activation of a slow Na+ current. The delayed depolarization was reduced after nerve transection. The refractory period of transmission of the action potential was shortened in the transected nerves, but that of the delayed depolarization was prolonged. The changes were largest when the sural nerve was cut and ligated [control: 38.1 +/- 1.7% (n = 5); injury: 24.5 +/- 2.8% (n = 5), P < 0.05], which prevented reconnection to its peripheral target. When the nerve was crushed and allowed to reestablish peripheral target connections, the delayed depolarization was minimally effected. These results indicate that the changes in Na+ channel organization following peripheral target disconnection observed on cutaneous afferent cell bodies also occur on their axons.

Pathogenesis of hyponatremia following subarachnoid hemorrhage due to ruptured cerebral aneurysm

BACKGROUND

Hyponatremia following subarachnoid hemorrhage (SAH) occurs due to the inappropriate secretion of antidiuretic hormone (SIADH). However, this condition is also sometimes associated with certain dehydration states.

METHODS

To clarify the pathogenesis, daily values of urine volume, water balance, and sodium balance (Na Bal) were correlated with plasma levels of atrial natriuretic peptide (ANP), antidiuretic hormone (ADH), and plasma renin activity (PRA) in 31 cases of SAH.

RESULTS

Na Bal was markedly negative on days 2 and 3. Cumulative Na Bal showed continuous negative values until day 10 following SAH. ANP values showed a consistent elevation, while ADH showed only an initial surge. PRA, as the gross indicator of circulatory volume, showed a lack of suppression, indicating no increase in the circulatory volume.

CONCLUSION

Hyponatremia following SAH therefore appears to be the result of increased natriuresis, due to the inappropriate elevation of ANP rather than SIADH. In this situation, water restriction should not be recommended, since the circulatory volume is decreased.

Restoration of normal conduction properties in demyelinated spinal cord axons in the adult rat by transplantation of exogenous Schwann cells

Although remyelination of demyelinated CNS axons is known to occur after transplantation of exogenous glial cells, previous studies have not determined whether cell transplantation can restore the conduction properties of demyelinated axons in the adult CNS. To examine this issue, the dorsal columns of the adult rat spinal cord were demyelinated by x-irradiation and intraspinal injections of ethidium bromide. Cell suspensions of cultured astrocytes and Schwann cells derived from neonatal rats transfected with the (beta-galactosidase) reporter gene were injected into the glial-free lesion site. After 3-4 weeks nearly all of the demyelinated axons were remyelinated by the transplanted Schwann cells. The dorsal columns were removed and maintained in an in vitro recording chamber; conduction properties were studied using field potential and intra-axonal recording techniques. The demyelinated axons exhibited conduction slowing and block, and a reduction in their ability to follow high-frequency stimulation. Axons remyelinated by transplantation of cultured Schwann cells exhibited restoration of conduction through the lesion, with reestablishment of normal conduction velocity. The axons remyelinated after transplantation showed enhanced impulse recovery to paired-pulse stimulation and greater frequency-following capability as compared with both demyelinated and control axons. These results demonstrate the functional repair of demyelinated axons in the adult CNS by transplantation of cultured myelin-forming cells from the peripheral nervous system in combination with astrocytes.

The anticonvulsant gabapentin enhances promoted release of GABA in hippocampus: a field potential analysis

The mechanism of action of the recently developed anticonvulsant gabapentin (GBP) used for treatment of partial seizures [12] is largely unknown. Rat hippocampal slices were maintained in vitro and the effects of microapplication of nipecotic acid (NPA), which promotes the release and blocks uptake of GABA, on the synaptically-evoked population excitatory postsynaptic potential (EPSP) were assessed before and after 1 h bath application of GBP. GBP treatment did not alter the population EPSP amplitude to paired or multiple stimuli, but nearly doubled the shunting effects of NPA on the EPSP with no effect on the presynaptic volley. The NPA-induced shunting of the EPSP was bicuculline-sensitive, indicating its mediation by GABAA receptor activation. These results suggest that GBP may increase free GABA levels in hippocampal cells, the release of which may be enhanced under conditions of promoted GABA release. Moreover, the study presents a methodology to electrophysiologically assess relative free GABA levels using field potential analysis in the adult rat brain.

Gabapentin potentiates the conductance increase induced by nipecotic acid in CA1 pyramidal neurons in vitro

The anticonvulsant gabapentin (1-(aminomethyl)cyclohexane acetic acid) has been found to be effective for treatment of partial seizures, but the mechanism of action is unknown. Recent evidence from the rat optic nerve suggests that gabapentin may enhance promoted release of GABA, which is thought to be due to reverse operation of the GABA transporter. We have used whole-cell patch clamp recordings from CA1 pyramidal neurons in hippocampal slices to directly measure currents induced by nipecotic acid (NPA) during exposure to gabapentin. Under control conditions, pressure microejection of NPA increased whole-cell conductance with a reversal potential equal to the chloride equilibrium potential. This response was mimicked by GABA application, and blocked by bicuculline. The response to NPA was also present after blockade of synaptic transmission in the presence of calcium-free solution. These results are consistent with NPA promoting nonvesicular release of GABA from neighboring neurons or glia via reverse operation of the GABA uptake system, which then activated GABAA receptors on the recorded neurons. In control solution, the response to NPA slowly decreased over 45 min to approximately 50% of the initial response, consistent with GABAA receptor 'rundown'. However, in the presence of gabapentin there was a slow increase in the response, reaching approximately 170% of the control level after 45 min of gabapentin exposure. These results demonstrate that gabapentin enhances the promoted release of GABA by more than three-fold. The potentiation of the NPA response may be due to gabapentin increasing cytosolic GABA in neighboring cells via a delayed metabolic effect, and would have the functional effect of increasing neuronal inhibition during periods of hyperexcitability.

Norepinephrine modulates excitability of neonatal rat optic nerves through calcium-mediated mechanisms

We report that norepinephrine markedly increases excitability of neonatal rat optic nerves. To investigate the mechanisms of the norepinephrine-induced excitability increase, we studied isolated optic nerves from 42 neonatal (< three days old) and five adult (> three months old) Long-Evan's hooded rats. Norepinephrine (10(-6), 10(-5) and 10(-4) M) rapidly and reversibly increased the amplitude (mean +/- S.D.: 3.5 +/- 1.7%, 12.1 +/- 2.8% and 35.6 +/- 8.4%) of compound action potentials elicited by submaximal stimulation of neonatal optic nerves. The beta-1 adrenoceptor antagonist atenolol (10(-5) M) blocked the norepinephrine-induced increase in excitability but the alpha antagonist phentolamine (10(-5) M) did not. The beta agonist isoproterenol (10(-5) and 10(-4) M) increased response amplitudes (8.7 +/- 4.1% and 25.8 +/- 4.6%) but the alpha-1 agonist methoxamine and alpha-2 agonist clonidine did not. The beta antagonist propranolol blocked the isoproterenol effect. Replacing Ca2+ with Mg2+ or adding 0.8 mM of Cd2+ reversibly blocked the norepinephrine effects. Extracellular K+ concentrations did not change in optic nerves during norepinephrine application. Blockade of K+ channels with apamin (10(-6) M) or tetraethylammonium (10(-3) M) did not prevent the excitatory effects of norepinephrine. Adult rat optic nerves were insensitive to both norepinephrine (10(-4) M) and isoproterenol (10(-4) M). Our results indicate that norepinephrine increases neonatal optic axonal excitability through Ca(2+)-dependent mechanisms. The data suggest that the adrenoceptors are situated on the axons, that the excitability changes are not due to changes in extracellular K+ concentration or K+ channels sensitive to apamin or tetraethylammonium. The sensitivity of rat optic nerves to norepinephrine declined with age. Axonal adrenoceptors may play a role in optic axonal development and injury.

Delayed depolarization and slow sodium currents in cutaneous afferents

1. Intraaxonal recordings were obtained in vitro from the sural nerve (SN), the muscle branch of the anterior tibial nerve (ATN), or the deafferented ATN (dATN) in 5- to 7-wk-old rats. Whole-nerve sucrose gap recordings were obtained from the SN and the ATN. This allowed study of cutaneous (SN), mixed motor and muscle afferent (ATN), and isolated muscle afferent (dATN) axons. 2. Application of the potassium channel blocking agent 4-aminopyridine (4-AP) to ATN or dATN resulted in a slight prolongation of the action potential. In contrast, a distinct delayed depolarization followed the axonal action potential in cutaneous afferents (SN) exposed to 4-AP. The delayed depolarization could be induced by a single whole-nerve stimulus or by injection of constant-current depolarizing pulses into individual axons. The delayed depolarization often gave rise to bursts of action potentials and was followed by a prominent afterhyperpolarization (AHP). 3. In paired-pulse experiments on single SN axons, the recovery time (half-amplitude of the action potential) was 3.06 +/- 1.82 (SE) ms (n = 12). After exposure to 4-AP the recovery time of the delayed depolarization was considerably longer (half-recovery time: 99.0 +/- 28.3 ms; n = 15) than that of the action potential (18.8 +/- 9.1 ms; n = 16). 4. Application of tetraethylammonium (TEA) to cutaneous or muscle afferents alone had little effect on single action potential waveform. However, TEA reduced the amplitude of the AHP elicited by a single stimulus in cutaneous afferent axons after exposure to 4-AP and resulted in repetitive spike discharge. 5. The delayed depolarization and spike burst activity induced by 4-AP in SN was present in Ca(2+)-free solutions containing 1 mM ethylene glycol-bis (beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid and was not blocked by Cd2+ (1.0 mM). 6. We obtained whole-cell patch-clamp recordings to study Na+ currents from either randomly selected dorsal root ganglion neurons or cutaneous afferent neurons identified by retrograde labeling with Fluoro-Gold. The majority of the randomly selected neurons had a singular kinetically fast Na+ current. In contrast, no identified cutaneous afferent neurons had a singular fast Na+ current. Rather, they had a combination of kinetically separable fast and slow currents or a singular relatively slow Na+ current.(ABSTRACT TRUNCATED AT 400 WORDS)

Gabapentin increases GABA-induced depolarization in rat neonatal optic nerve

Membrane potential changes of rat neonatal optic nerves were studied in a sucrose-gap chamber. Nipecotic acid (NPA), which blocks uptake and promotes release of GABA, resulted in a bicuculline-sensitive depolarization (3.08 +/- 0.3 mV, n = 5). Pretreatment of the nerves with the anticonvulsant gabapentin (100 microM for 1 h) resulted in a near doubling of the NPA-induced depolarization (6.64 +/- 0.54 mV, n = 5). Gabapentin itself did not alter membrane potential, nor did brief applications of gabapentin enhance the NPA- or GABA-induced depolarization. Thus, gabapentin appears to enhance the releasable pool of GABA in this CNS neural system. These results have implications for the mechanism of the anticonvulsant properties of gabapentin.

[Technical tactics to preserve cortical venous drainage in interhemispheric approach for anterior communicating artery aneurysms]

The interhemispheric approach has been selected for clipping of the anterior communicating artery aneurysm located high above the sphenoidal plate, and in a posterior direction. However, this approach is sometimes complicated with postoperative hemorrhagic infarction due to excess brain retraction combined with damages of the cortical bridging veins. We have devised a modification in this approach to eliminate these complications. Our newly devised methods include the following; 1) Small bifrontal craniotomy performed, 2) Continuous ventricular drainage performed to minimize the effect of compression by the spatula during resection of interhemispheric fissure, 3) Bifrontal dural incision made along the frontal skull base, 4) Mobilization of the major cortical vein in the operated field, if necessary, by resection of the overlying arachnoid membrane with or without sacrificing its small tributaries, 5) Gradual dissection of the olfactory nerves according to the process of operation. We analysed the incidence of operative complications in thirteen consecutive cases with this approach. Major frontal ascending veins were carefully preserved in all cases. None showed hemorrhagic infarction, regardless of the cortical venous drainage patterns. The degree of smell preserved in 10% of the examined 11 cases was more than unilateral. In conclusion, this method is useful for the elimination of perioperative complications even in the acute stage of subarachnoid hemorrhage.

GABA and potassium effects on corticospinal and primary afferent tracts of neonatal rat spinal dorsal columns

The neurotransmitter GABA markedly depresses action potential conduction in neonatal rat spinal dorsal columns. However, GABA sensitivity of the dorsal columns declines with maturation and myelination. At seven to 14 days after birth, the corticospinal tract component of the dorsal columns is immature and unmyelinated compared to the cuneate-gracilis fasciculi. GABA and isoguvacine (a GABAA receptor agonist) were applied to isolated neonatal (seven to 14 days old) dorsal columns during recordings of conducted cuneate-gracilis fasciculi and corticospinal tract action potentials. GABA (10(-4) to 10(-3) M) significantly reduced amplitudes (-28.9% to -69.7%) and increased latencies (+4.8% to +23.9%) of cuneate-gracilis fasciculi responses but had less effect on corticospinal tract response amplitudes (-1.1% to -14.7%) and latencies (+0.9% to +6.2%). Likewise, isoguvacine (10(-5) to 10(-4) M) reduced amplitudes (-26.7% to -37.5%) and increased latencies (+11.2% and +24.0%) of cuneate-gracilis fasciculi responses but had little or no effect on corticospinal tract response amplitudes (-6.2% to -3.8%) or latencies (-0.8% to +1.5%). At 10(-4) and 10(-3) M, GABA rapidly increased extracellular K+([K+]e) from baseline levels of 3.0 mM to 3.7 +/- 0.4 and 6.6 +/- 1.4 mM in cuneate-gracilis fasciculi and increased corticospinal tract [K+]e to 3.9 +/- 0.4 and 4.4 +/- 0.4 mM (mean +/- S.D.). [K+]e declined during drug application and fell below baseline after drug washout. Cuneate-gracilis fasciculi responses, however, did not recover until several minutes after [K+]e returned to baseline. In separate experiments, increasing bath [K+]e concentrations to 3.7 and 6.6 mM reduced cuneate-gracilis fasciculi response amplitudes by only -7.6% and -29.6%. Latencies increased by +1.3% and +3.6% respectively. The results indicate that the cuneate-gracilis fasciculi are more sensitive to GABA than the corticospinal tract and that the GABA effect is not entirely due to [K+]e changes.

[Ventriculoperitoneal shunt using a continuously variable-resistance valve for management of hydrocephalus, especially for cases mimicking simple brain atrophy]

Twenty-two hydrocephalic patients with a ventriculoperitoneal shunt using a continuously variable flow resistance valve (Orbis-Sigma valve system; Cordis Corporation, USA) were reviewed to discuss usefulness of the shunt system. We divided the cases into two groups according to the demonstration of the cortical sulci in computed tomography (CT) as follows; A: progressive hydrocephalic cases mimicking simple brain atrophy, B: acute or subacute hydrocephalic cases with evidence of increased intracranial pressure. Patients in Group A had begun to present slowly progressive loss of activity, dementia and gait disturbance of various degrees after a long quiescent period following primary central nervous system injury. CT findings of these cases showed they were mimicking simple brain atrophy. Although the period of their deterioration was very long, ranging from 1 month to nine years, clinical signs improved in all cases after the shunt. None showed complications. Group B cases consisted of those with signs of increased intracranial pressure such as consciousness disturbance, nausea and vomiting. These cases showed poor demonstration of the cortical sulci in CT. Eleven out of thirteen cases showed satisfactory clinical improvement, though the size of the ventricle showed a slight decrease following shunt procedure. Only one case showed unilateral subdural effusion. In conclusion, this shunt system is useful for the management of ventricular enlarged cases mimicking simple brain atrophy as well as acute hydrocephalic cases. Troublesome consequences such as subdural effusion and hemorrhage rarely occur even in cases with low cerebrospinal pressure.

Successful removal of intracavernous neurinoma originating from the oculomotor nerve--case report

An oculomotor neurinoma was confirmed intraoperatively to be located in the lateral wall of the cavernous sinus in a 55-year-old male. By protruding into the true venous cavity, it caused obliteration of the blood flow in the cavernous sinus. The tumor was totally removed without entering the true venous cavity of the cavernous sinus. The cavernous sinus was closed by suturing the dural membrane to the thin fibrous membrane, preventing intraoperative bleeding.

[Significance of plasma atrial natriuretic peptide measurement during the management of hyponatremia in neurosurgical patients]

We have examined the total number of admitted cases to clarify the pathogenesis of hyponatremia during the management of neurosurgical patients. We experienced 32 cases of hyponatremia during the past year by measuring the sodium balance and atrial natriuretic peptide (ANP) level. According to these two factors, we divided the cases into three groups. The first group shows normal ANP levels in spite of hyponatremia. Low administration of the sodium was thought to be the cause in these cases. The second group shows the elevated ANP levels with a positive sodium balance. Elevated circulatory volume due to the inadequate level of antidiuretic hormone and mild heart and/or kidney failures cause these conditions. Water restriction and/or diuresis were effective methods in the management of the cases. The last group shows the elevated ANP levels with a negative sodium balance. There is a statistically significant negative correlation between sodium balance and the ANP level. Marked natriuresis due to the elevated ANP causes the decrement of the circulatory volume in these cases. Pathogenesis of the last group is very important in the management of neurosurgical patients in an acute state, especially in subarachnoid hemorrhage cases. The decrement of the systemic circulatory volume would jeopardize the patient's neurological condition. In this group, water restriction that has been commonly recommended is contraindicated. Satisfactory water and sodium replenishment seems to be the best recommended treatment for this group.

[A case presenting a severe paralytic ileus during the continuous intravenous injection of nicardipine hydrochloride]

We report on a case of hypertensive intracerebral hematoma associated with a severe paralytic ileus during a continuous injection of nicardipine hydrochloride. The patient (63 year-old male) had been admitted with a left hemiparesis. On the second day of admission, the patient received a continuous intravenous injection of nicardipine hydrochloride following the failure to get a constant reduction of systemic blood pressure. The initial dose of the drug was 2 micrograms/kg/min. It was administered for 22 days and the average daily dosage was 187mg. On the eighth day following the beginning of the drug administration, he complained of abdominal distention. Abdominal X-ray photogram revealed a marked air collection in the colon. Despite various forms of treatments, the abdominal distention continued for 20 days until cessation of the drug administration. The paralytic ileus in this case was most likely caused by the following; 1) a relatively large amount of the drug was administered via the continuous intravenous route, 2) unexpected accumulation of the drug in the digestive tract may occur due to the dysfunction of the liver and the kidney, 3) clearance of the drug in humans may be lower than the expected value obtained from animal experiments.