Cerebral revascularization using omental transplantation for childhood moyamoya disease

Between January, 1986, and October, 1990, 30 children with moyamoya disease, aged from 2 to 17 years, underwent omental transplantation to either the anterior or the posterior cerebral artery territory. The mean follow-up period was 3.8 years, ranging from 1.6 to 6.4 years. Seventeen patients had symptoms of monoparesis, paraparesis, and/or urinary incontinence and were treated using unilateral or bilateral omental transplantation to the anterior cerebral artery territory. Eleven patients had visual symptoms and were treated with unilateral or bilateral omental transplantation to the posterior cerebral artery territory. Two patients had symptoms associated with both the anterior and the posterior cerebral arteries, and were treated with dual omental transplantations. All 19 patients treated with omental transplantation to the anterior cerebral artery and 11 (84.6%) of the 13 treated with omental transplantation to the posterior cerebral artery showed improvement in their neurological state. Patients with more collateral vessels via the omentum had more rapid and complete improvement in their neurological state. Patients with severe preoperative neurological deficits associated with the posterior cerebral artery had persistence of their symptoms.

Stability of liposomes in vitro and their uptake by rat Peyer's patches following oral administration

To evaluate the usefulness of liposomes as a carrier for the targeted delivery of antigens to gut-associated lymphoid tissue, liposomal stability and uptake by rat Peyer's patches were investigated. Liposomes composed of distearoylphosphatidylcholine, phosphatidylserine, and cholesterol (DSPC-liposome), or dipalmitoylphosphatidylcholine, phosphatidylserine, and cholesterol were stable in acidic solution (pH 2.0), diluted bile, and pancreatin solution. Following the oral administration of liposomes to rats, rhodamine B-PE incorporated in the lipid phase of DSPC-liposomes was preferentially taken up by Peyer's patches in the lower ileum. The uptake of rhodamine B-PE from DSPC-liposomes larger than 374 nm in mean diameter was high. Orally administered DSPC-liposomes of a large diameter thus appear to serve effectively as a vehicle for delivering antigens to Peyer's patches.

Supratentorial low-grade astrocytoma. Correlation of computed tomography findings with effect of radiation therapy and prognostic variables

BACKGROUND

In supratentorial low-grade astrocytoma, radiation therapy effects and prognostic factors, especially with respect to computed tomography (CT) findings, are not yet well established. A retrospective analysis of 119 patients with this disease (histologically confirmed ordinary astrocytoma) therefore was conducted.

METHODS

Between 1965 and 1989, 101 patients received postoperative radiation therapy, whereas 18 patients received surgery alone. Radiation was directed to the tumor plus a 1- to 3-cm margin in almost all cases; the dose range was 41 to 66 Gy (mean, 57 Gy). CT scan was performed before treatment on 74 patients. Postoperative survival rates were compared by both univariate and multivariate analyses.

RESULTS

The 5- and 10-year survival rates for the irradiated group were 60% and 41%, respectively, which were significantly better than those for the surgery-alone group (37% and 11%, P = 0.048). Among various potential prognostic factors for the irradiated patients, only a lower age was associated with a better prognosis. Sex, tumor site (deep-seated or not), extent of surgery, radiation dose and field, and adjuvant chemotherapy did not influence the prognosis significantly. Among various CT findings, a clear tumor margin, a maximum tumor area less than 25 cm2, presence of a cyst, and lack of mass effect were associated with a better prognosis on univariate analysis (P = 0.02-0.12), but contrast enhancement was not related to prognosis. On multivariate analysis, however, mass effect was the only significant factor.

CONCLUSIONS

Radiation therapy appears definitely to be effective in improving the prognosis for low-grade astrocytoma. Younger age, and the absence of mass effect determined by CT, were associated significantly with a better prognosis.

Ischemic tolerance due to the induction of HSP70 in a rat ischemic recirculation model

Various studies have demonstrated an increase in heat shock protein 70 (HSP70) synthesis in the brain following transiently induced ischemia, suggesting a protective role for HSP70 against ischemic insult. In this study, we determined the time course of HSP70 mRNA and protein induction in rat hippocampus following ischemia using Pulsinelli's four-vessel occlusion model, and suggested a protective role for HSP70 induction in limiting ischemic damage to neurons and delayed neuronal death. In Northern blotting analysis using human HSP70 DNA as a probe, the accumulation of HSP70 mRNA after 5 min ischemia became evident at 4 h, and continued until 16 h, while after 30 min ischemia, HSP70 mRNA appeared at 2 h, and continued above control level until 24 h after treatment. In immunoblot analysis using anti-HSP70 antibody, induction of HSP70 protein appeared 24 h and reached a maximum 48 h after 5 min ischemia. In immunohistochemical analysis using anti-HSP70 antibody, staining was not detected in CA1 neurons until 16 h after 5 min ischemia, but staining in CA1 gradually increased 1 day after ischemia and reached a maximum level 2 days after ischemia. Similar time profiles in the staining pattern of HSP70 protein were observed in CA3 and CA4 neuronal cells following 30 min ischemia. When rats pretreated with 5 min ischemia (non-lethal for CA1 pyramidal neurons) were exposed to a 30 min, lethal period of ischemia, 2 days after pretreatment, considerable staining of HSP70 was observed. Pretreated rats had much less neuronal damage in the CA1 sector than did rats subjected to lethal, 30 min ischemia alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Glucose consumption in recurrent gliomas

In order to investigate the clinical significance of glucose consumption (GC) in recurrent gliomas, positron emission tomography with 18F-labeled fluorodeoxyglucose was measured in 18 cases of histologically verified recurrent gliomas. The GC of the tumors were categorized into four groups. Five tumors were in Group IV, the highest GC, four were in Group III, eight were in Group II, and one was in Group I. Masses in Groups III and IV were clearly defined as a hot spot higher than or similar to the GC of the contralateral cortex. Half of the recurrent gliomas showed the lower GC of Group I or II, but two thirds of these were histologically high-grade gliomas. Although GC in the recurrent gliomas did not always increase as expected, a focal increase of GC, even mild and small, in the area of previous surgery is diagnostically important. Tumors with high GC showed high histological malignancy, irrespective of tissue damage. Patients with tumors of low GC had longer survival rates than those with high GC, although statistical significance was not obtained. Thus, positron emission tomography with 18F-labeled fluorodeoxyglucose was useful for detecting the recurrence of gliomas and suggesting their histological malignancy and prognosis. Care should be taken because viable tumor cells could be present in areas of low GC and small recurrent masses could be missed because of the poor spatial resolution of positron emission tomography.

Analysis of secretion and expression of platelet-derived growth factor in cultured endothelial cells from stroke-prone spontaneously hypertensive rat

1. We characterized the endothelial cell-derived growth factors of SHRSP and Wistar Kyoto rats (WKY), respectively and found that platelet-derived growth factor (PDGF)-B chain related growth factor constituted a major portion of the mitogenic activity of the conditioned media of endothelial cells from both animals. There were no remarkable qualitative differences between the endothelial cell-derived growth factors of SHRSP and WKY. 2. Northern analysis revealed that the expression of PDGF-B chain was 2-4-fold enhanced in cultured aortic endothelial cells of SHRSP. This enhanced expression of PDGF-B chain, which may be induced under chronic hypertensive conditions, is suggested to contribute to the increase in endothelial cell-derived growth factors reported in this animal.

Supratentorial low-grade astrocytoma. Correlation of computed tomography findings with effect of radiation therapy and prognostic variables

BACKGROUND

In supratentorial low-grade astrocytoma, radiation therapy effects and prognostic factors, especially with respect to computed tomography (CT) findings, are not yet well established. A retrospective analysis of 119 patients with this disease (histologically confirmed ordinary astrocytoma) therefore was conducted.

METHODS

Between 1965 and 1989, 101 patients received postoperative radiation therapy, whereas 18 patients received surgery alone. Radiation was directed to the tumor plus a 1- to 3-cm margin in almost all cases; the dose range was 41 to 66 Gy (mean, 57 Gy). CT scan was performed before treatment on 74 patients. Postoperative survival rates were compared by both univariate and multivariate analyses.

RESULTS

The 5- and 10-year survival rates for the irradiated group were 60% and 41%, respectively, which were significantly better than those for the surgery-alone group (37% and 11%, P = 0.048). Among various potential prognostic factors for the irradiated patients, only a lower age was associated with a better prognosis. Sex, tumor site (deep-seated or not), extent of surgery, radiation dose and field, and adjuvant chemotherapy did not influence the prognosis significantly. Among various CT findings, a clear tumor margin, a maximum tumor area less than 25 cm2, presence of a cyst, and lack of mass effect were associated with a better prognosis on univariate analysis (P = 0.02-0.12), but contrast enhancement was not related to prognosis. On multivariate analysis, however, mass effect was the only significant factor.

CONCLUSIONS

Radiation therapy appears definitely to be effective in improving the prognosis for low-grade astrocytoma. Younger age, and the absence of mass effect determined by CT, were associated significantly with a better prognosis.

[Effects of interferon-gamma on cytotoxicity of murine activated macrophages against murine glioma cells]

We studied the effects of mouse IFN-gamma on the cytotoxic activity of murine activated macrophages (M phi) against mouse VM-Glioma cells (H-2b). Activated M phi were obtained from peritoneal exudate cells of mice from four strains, C57BL/6 (H-2b), C3H/He(H-2k), DBA/2 (H-2d), and BALB/c (H-2d), following intraperitoneal injection of (1) LPS 200 micrograms, (2) BCG 200 micrograms, (3) C. parvum 200 micrograms, or (4) MDP 350 micrograms 7 days prior to 20-hr 51Cr release-assay. Of the various combination of mouse strains and activating agents tested, that of activated M phi of the C3H/He mouse with induction by LPS had the most tumoricidal effect against the glioma cells, which was not MHC restricted. Although LPS-activated M phi underwent marked loss of cytotoxicity following initiation of in vitro culture, this 24 hr pretreatment with IFN-gamma inhibited this reduction in tumoricidal effects in a dose-dependent fashion. On the other hand, 24 hr pretreatment of target cells with IFN-gamma did not increase their susceptibility to lysis by activated M phi. These findings suggest that IFN-gamma augments the in vitro tumoricidal activation of M phi; This effect appears to be unrelated to any influence of IFN-gamma on target sensitivity to lysis by macrophages.

[Delayed cerebral dysautoregulation after recirculation of cerebral ischemia]

Sequential changes of cerebral autoregulation were studied in 20 cats after recirculation of cerebral ischemia. The cerebral autoregulation was evaluated by autoregulation index (A.I.), calculating % delta cerebral blood flow (CBF)/delta cerebral perfusion pressure (CPP), with changing the mean arterial blood pressure (MABP) within 80-130 mmHg. Duration of ischemic insult was 15 min after disappearance of direct cortical response (DCR). Following recovery of cerebral circulation, MABP, CBF and intracranial pressure (ICP) were observed sequentially for at least 48 hours. In 6 of 20 cats the autoregulation was disturbed early after recirculation, and the ICP was increased, resulting in no cerebral blood flow (early deteriorated group). In the other 14 cats the autoregulation was restored immediately, but in 7 of the 14 cats it was disturbed again after 24 hours following recirculation (delayed deteriorated group), finally the ICP was elevated and the CBF became 0 as same as early deteriorated group. In another 7 cats it was not disturbed until 5 days. The changes in CBF following insult were five patterns. These were classified into type A (Gradual decrease), type B (Transient increase), type C (Constant maintenance), type D (Relatively rapid decrease) and type E (Rapid decrease). The delayed cerebral dysautoregulation occurred in the types except for type A and type E. These results suggested there was close relation between delayed dysautoregulation and delayed neuronal dysfunction that we reported previously. Moreover, we considered the delayed dysautoregulation could be speculated from the value of ICP/CBF immediately after recirculation and the pattern of the changes in CBF during ischemic insult.

[Identification of Mycobacterium tuberculosis complex and Mycobacterium avium-intracellulare complex by using nonisotopic DNA probes]

A total of 31 clinical isolates of mycobacteria consisting of 21 strains of M. avium-intracellulare complex (ten strains each of M. avium and M. intracellulare identified by specific 125I-labeled DNA probes and one strain of M. avium-intracellulare complex identified by conventional biochemical tests) and 10 strains of M. tuberculosis (identified by a specific 125I-labeled DNA probe) were subjected to identification by hybridization protection assay (HPA) with an acridinium-ester (AE) labeled DNA probe. The results thus obtained were in complete agreement with those obtained by 125I-labeled DNA probes (30 strains) or by conventional biochemical tests (one strain). HPA by the AE-labeled DNA probe is safe, simple and rapid, and can be done with ease in any clinical laboratory.

A simple and efficacious criterion based on serum LH levels to time hCG administration for human in vitro fertilization

OBJECTIVE

To test the efficacy of a simple criterion--LH level--for administration of hCG in an IVF program.

DESIGN

Prospective, with retrospective analysis of other criteria for hCG administration.

SETTING

University hospital IVF program.

PATIENTS AND INTERVENTIONS

Eighty-four patients, in 110 cycles, were given 150-300 IU at 10-11 A.M. daily beginning on day 3 of the cycle. Serum LH measured daily 8:30-9:30 A.M., hCG administered on night of day LH level first exceeded J, defined as minimum value + (day 3 value-minimum) x 1/3.

OUTCOME MEASURES

Pregnancy (after IVF + ET); serum concentrations of estradiol and LH.

RESULTS

Total and ongoing pregnancy per cycle: 35% and 27% respectively. If hCG is administered one day early or late by the J criterion, the pregnancy rate is reduced.

CONCLUSIONS

Pregnancies occurred over wide follicle diameter (14-21 mm) and estradiol level (229-2,050 pg/mL) ranges. LH is recommended for timing hCG administration.

[A large vertebrobasilar junction aneurysm grown at the proximal end of basilar artery fenestration--usefulness of balloon occlusion test with 99mTc-HMPAO SPECT under induced hypotension and consideration in therapeutic strategies]

A 48-year-old lady suffered a transient loss of consciousness. CT and MRI revealed a large vascular lesion compressing the left lower pons. Angiography revealed a large aneurysm at vertebro-basilar junction, dome of which projected anteriorly and left to midline. Her previous vertebral angiogram taken 10 years ago when she suffered a subarachnoid hemorrhage from the left MCA aneurysm, had showed a fenestration of lower basilar artery without apparent aneurysm. Bilateral super-selective vertebral angiograms revealed that the aneurysm arose at the proximal end of the fenestration, and vertebrobasilar junction was incorporated into the aneurysm indicating broad neck aneurysm. The left posterior communicating artery was well developed. Balloon test occlusion (BTO) of bilateral vertebral artery was performed under normotension and induced hypotension. 99mHM-PAO SPECT was used to examine cerebral blood flow (CBF) during hypotensive BTO. The patient tolerated the test and CBF imaging showed insignificant sight decrease in bilateral cerebellar hemispheres. Exploration of the aneurysm was carried out by the right far lateral suboccipital approach. Bilateral vertebral arteries and the right segment of the basilar artery fenestration were identified. Neck clipping of the aneurysm with reconstruction of the parent vessels were tried with fenestrate clip. However, narrow operative field and large dome of the aneurysm made it hard to identify the left segment of the fenestration. Neck clipping was given up and clipping of bilateral vertebral arteries were performed distal to posterior inferior cerebellar artery with three body clippings. The patient showed moderate postoperative left lower nerve palsy, which was gradually improved in several weeks. Follow-up angiography revealed no opacification of the aneurysm.(ABSTRACT TRUNCATED AT 250 WORDS)

Uptake of phosphatidylserine liposomes by rat Peyer's patches following intraluminal administration

Uptake of the nonabsorbable marker 6-carboxyfluorescein was investigated both free and encapsulated in liposomes as a function of their surface charge and hydrodynamic diameter in rat Peyer's patch and nonpatch tissue. Significant uptake of the marker occurred only when encapsulated in liposomes consisting of at least 25 mol% phosphatidylserine and was highest in Peyer's patches. 6-Carboxyfluorescein encapsulated in liposomes equal to or greater than 374 nm was preferentially taken up by Peyer's patches. There was a trend to higher uptake in lower intestinal segments. These findings were supported by fluorescence microscopic observations. Uptake by Peyer's patches was specific for negatively charged liposomes as judged from competition studies.

Role of histocompatibility antigen gene and protooncogene expressions in intracerebral tumorigenicity of mouse neuroblastoma

The role of N-myc, c-src, and major histocompatibility complex (MHC, H-2 in the mouse) class I antigen gene expressions in dimethyl sulfoxide (DMSO)-induced differentiation and intracerebral tumorigenicity was examined using a mouse MNB85 neuroblastoma cell line. A fluorescence-activated cell sorter disclosed cell-surface MHC enhancement by DMSO, causing an increase in cytotoxic T-lymphocyte sensitivity. Southern blot analysis verified a single copy of the proto-oncogenes and MHC deoxyribonucleic acids in both untreated and DMSO-treated MNB85 cells. Northern blot analysis indicated that DMSO treatment induced a decrease in N-myc and an increase in c-src and MHC messenger ribonucleic acids. Nuclear run-off transcription assay revealed down-regulation of N-myc at a posttranscriptional level, contrasted with primary up-regulation of c-src at a transcriptional level. Immunoprecipitation after treatment with enzyme endo-beta-N-acetyl-glycoseamidase H proved that the terminal glycosylation of MHC heavy-chain gene products normally occurs in the Golgi apparatus of MNB85 cells. Intracerebral tumorigenicity assay showed that cells highly MHC-expressed by DMSO were less tumorigenic than untreated cells in association with DMSO-augmented cytotoxic T-lymphocyte susceptibility. These results suggest that proto-oncogenes may be linked to cellular differentiation, while cell-surface MHC gene expression influences intracerebral immunosurveillance.

Enhancement of systemic and mucosal immune responses following oral administration of liposomes

The effects of liposomes on the systemic and mucosal immune response were investigated using bovine serum albumin (BSA) in BALB/c mice. Following three oral administrations of varied formulations at 1-week intervals, serum BSA-specific IgG levels were increased significantly by BSA encapsulated in liposomes and moderately by a mixture of liposomes and BSA. Serum and salivary BSA-specific IgA levels were elevated by BSA-encapsulating liposomes only. Liposomes thus activate not only the systemic immune response but also the mucosal immune response following their oral administration. However, no increase in salivary IgA levels was observed by intraperitoneal or subcutaneous injection of BSA-encapsulating liposomes. The production of IgA is closely related to the oral administration of liposomes encapsulating antigens. Liposomes thus function as carriers of oral vaccines against various infections of the mucosal surface.

Developmental expression of trkB and low-affinity NGF receptor in the rat retina

Brain-derived neurotrophic factor (BDNF) promotes the survival of retinal ganglion cells, but these effects are dependent on the developmental stages, and a number of retinal ganglion cells are eliminated during pre- and neonatal stages. We have examined the expression of BDNF receptors, trkB and low-affinity nerve growth factor receptor (LNGFR), in the rat retina during these period using Northern blot analysis. The expression of trkB and LNGFR displayed two peaks during embryonic day 17 (E17) through postnatal day 1 (P1), and during P14-P17, indicating that it may play an important role in neuronal development and neuronal cell death.

Novel antibodies specific for proteolyzed forms of protein kinase C: production of anti-peptide antibodies available for in situ analysis of intracellular limited proteolysis

We show here a novel method for the in situ analysis of proteolyzed proteins in a cell. As a model, we focused on protein kinase C (PKC) beta, which is cleaved at a specific site between the catalytic and regulatory domains by calpain, the intracellular calcium-activated neutral proteinase. To detect proteolyzed PKC beta 'cleavage-site-directed antibodies', which specifically recognize the amino-terminal region of the catalytic fragment but do not cross-react with the unproteolyzed enzymes, were raised using synthetic peptide. The synthetic peptide used in this study was QGTKVPEEKTT, corresponding to the amino-terminal region of the catalytic fragment from human PKC beta generated by calpain. Rabbits were immunized with the synthetic peptide after conjugation with a carrier protein. Antibodies obtained reacted with the 46-kDa catalytic fragment of PKC beta, whereas they did not cross-react with unproteolyzed enzyme nor other fragments with different amino-termini. Thus, our antibody is specific to the amino-terminal sequence QGTKVPEEKTT, but does not recognize the same sequence located internally in native PKC beta. When human monoblast U937 cells were treated with calcium ionophore, the catalytic fragment of PKC beta was detected in the cytosol by immunoblotting with the antibody. However, this antibody did not bind unproteolyzed 80-kDa PKC beta, although this form was dominant in the cytosol of the calcium ionophore-treated cells. We could also detect comparable amounts of catalytic fragment in the calcium ionophore-treated cells by immunocytochemical staining with the same antibody. Our method was applied to examine the proteolysis of PKC beta in neutrophils stimulated with various reagents.

Degenerative changes in the internal elastic lamina relating to the development of saccular cerebral aneurysms in rats

In order to investigate the developmental mechanism of saccular cerebral aneurysms, changes in the internal elastic lamina at the junction of the anterior cerebral artery and the olfactory artery were electronmicroscopically studied in 6 control and 6 experimental rats undergoing ligation of the left carotid artery and branches of both renal arteries. In the control group, spontaneous destructive changes occurred on the luminal side of the internal elastic lamina and progressed from the luminal towards the abluminal side as the elastic lamina advanced to the apex. Close to the apex, these changes invaded and disrupted the whole elastic lamina. The elastic lamina was replaced by sparsely lined up lumps of elastic tissue in the walls of early aneurysmal alterations, and was atrophied and disappeared totally in the walls of aneurysmal alterations that had reached an advanced stage. These spontaneous changes were in agreement with reports in the literature and our own previous investigations. From the findings in the experimental rats it becomes likely that the aneurysmal changes in the elastic lamina are exaggerated forms of the normal catabolic metabolism. Therefore its synthesis on the abluminal side no longer balances with the catabolism on the luminal side. It is strongly suggested that aneurysmal alterations progress from the luminal towards the abluminal side of arterial walls and that the lytic process of elastase might play a role in the degenerative changes in aneurysmal development.

A point mutation found in the WT1 gene in a sporadic Wilms' tumor without genitourinary abnormalities is identical with the most frequent point mutation in Denys-Drash syndrome

We have analyzed exon 9 of the WT1 gene of 18 non-familial/sporadic unilateral Wilms' tumors (WTs) from Japanese patients, by the polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) method. After screening these WTs, a nucleotide alternation, which was present on both alleles, was found in only one case. Furthermore, PCR-SSCP analysis of the constitutional DNA revealed that this patient carried the mutation on only one allele in the germline. Sequence analysis showed that the tumor carried a point mutation (C-1180 to T-1180) in WT1 exon 9 of both alleles, resulting in an Arg-394 to Trp-394 amino acid substitution within the third zinc finger domain of the WT1 product. Interestingly, this mutation is identical with the most frequent point mutation associated with the Denys-Drash syndrome. However, the classical triad of Denys-Drash syndrome does not apply to this patient. This is in the first report of the point mutation in the zinc finger domain of both WT1 alleles in a sporadic unilateral WT without genitourinary abnormalities, and the mutation suggests that some sporadic WTs carry the Denys-Drash WT1 mutations.

[Identification of Mycobacterium avium-intracellulare complex in Tohoku district of Japan by using DNA probes]

Attempts were made to identify Mycobacterium avium and Mycobacterium intracellulare in the M. avium-intracellulare complex (MAC) isolated in the Tohoku district of Japan by using DNA probes (Gen-Probe; Rapid Diagnostic System) which are specific for M. avium, M. intracellulare and M. tuberculosis complex, respectively. In the Tohoku district, the ratio of M. avium isolates (80%) exceeded that of M. intracellulare isolates. It was thus shown that, in the Tohoku district where no data concerning the ratio of M. avium to M. intracellulare isolates had been available, the ratio of M. avium by far exceeded that of M. intracellulare.

A new approach to the integrity of dual blood-brain barrier functions of global ischemic rats. Barrier and carrier functions

BACKGROUND AND PURPOSE

We studied the influence of reperfusion on carrier and barrier functions of the blood-brain barrier after transient global ischemia in rats.

METHODS

We used iodine-125-labeled 3-iodo-alpha-methyl-L-tyrosine and carbon-14-labeled sucrose as tracers for studying carrier and barrier functions of the blood-brain barrier, respectively. Brain uptakes of these two tracers were measured in Wistar rats subjected to either 15- or 30-minute four-vessel occlusion developed by Pulsinelli and Brierly before recirculation for 3, 6, 24, 48, and 72 hours. Tracer (5 microCi) was injected intravenously in each rat 30 minutes before killing the animal.

RESULTS

Following 15- or 30-minute ischemia, [14C]sucrose uptakes were significantly higher at 3 and 6 hours of reperfusion before recovery to control values after reperfusing for 24 to 48 hours in almost all brain regions. However, a rebound in radioligand uptake was significantly manifested in some sites at 72 hours after reperfusion (p < 0.05 to p < 0.01). Uptakes of 125I-3-iodo-alpha-methyl-L-tyrosine were brain site-dependent: significantly (p < 0.05) higher in cortex (3 and 48 hours after reperfusion) and thalamus (3, 6, and 48 hours after reperfusion) but significantly (p < 0.05 to p < 0.01) lower in striatum, cortex (72 hours after reperfusion), and midbrain (6, 24, and 72 hours after reperfusion). Because the [14C]sucrose uptake in brain was 10% lower than that of 125I-3-iodo-alpha-methyl-L-tyrosine, the change in absolute transport of the latter tracer was approximated to its brain uptake.

CONCLUSIONS

The carrier and barrier functions of the blood-brain barrier should be evaluated separately. The radioligand 125I-3-iodo-alpha-methyl-L-tyrosine may serve as a useful tool to evaluate the carrier function of the blood-brain barrier after transient cerebral ischemia in rats.

Extension of optic nerve fibers on genetically modified cells producing brain-derived neurotrophic factor

Since brain-derived neurotrophic factor (BDNF) promotes the survival of retinal ganglion cells (RGCs), we transfected a rat BDNF cDNA into rat fibroblasts, and retinal fragments of rat embryos were cultured on cell monolayers of these cells. Retinal fragments showed enhanced neurite extension on BDNF-transfected cells compared with that on control cells. The degree of the neurite extension, however, decreased depending upon the embryonic stages. These results suggest that fibroblasts genetically modified to produce BDNF might be a promoter of neurite extension by RGCs, but this does not apply to the RGCs of late embryonic stages.