Bone morphogenetic protein type IB receptor is progressively expressed in malignant glioma tumours

The distribution of bone morphogenetic protein (BMP) type I receptors and the activin type I receptor (ActR-I) was investigated in 16 cases of human glioma and five cases of non-tumourous gliosis tissue by immunohistochemical technique. Both BMP type IA (BMPR-IA) and the type IB (BMPR-IB) receptors were detected in human glioma cells. A significant increase in BMPR-IB in tumour cells was observed in malignant glioma compared with both low-grade astrocytomas (n=16, P<0.005) and gliosis (n=13, P<0.001). However, enhancement of BMPR-IA staining was moderate and ActR-I staining was only weakly expressed in the malignant glioma tumours. Osteogenic protein (OP)-1/BMP-7, which is known to bind BMPR-IA, BMPR-IB and ActR-I, was expressed in nervous tissue and was also detected in anaplastic areas of malignant glioma. In contrast to the tissue materials, BMPR-IA was expressed to a stronger degree than BMPR-IB in human glioma cell lines; the growth of these cells was suppressed by OP-1. These results suggest the presence of BMP receptors and a functional role for BMPs in malignant glioma.

Expression of TGF-beta type I and type II receptors in rat eyes

Transforming growth factor beta (TGF-beta) transduces signals through mediation of type I and type II serine/threonine kinase receptors. The expression of TGF-beta type I (T beta R-I) and II (T beta R-II) receptors in rat eyes was investigated immunohistochemically. T beta R-I and T beta R-II immunoreactivity was detected in corneal and conjunctival epithelial cells, corneal endothelial cells, ciliary epithelial cells, lens epithelial cells, retinal pigment epithelial cells, and choroidal vessels. This co-expression of T beta R-I and T beta R-II indicates that the above cells respond to TGF-beta and, because TGF-beta is reported to be produced in ocular tissues, that it may have important autocrine and/or paracrine roles in the growth and metabolism of ocular tissues in situ.

Atrophic changes of gastric mucosa are caused by Helicobacter pylori infection rather than aging: studies in asymptomatic Japanese adults

BACKGROUND

The current study was designed to evaluate the effect of aging and Helicobacter pylori infection on the gastric mucosa in asymptomatic Japanese adults.

MATERIALS AND METHODS

Eighty-five asymptomatic healthy adults were recruited from a health-screening center in Sapporo. All subjects underwent endoscopy and gastric biopsy, and serum was obtained for IgG antibodies to H. pylori, serum gastrin, and pepsinogen levels.

RESULTS

The prevalence of atrophic change of the gastric mucosa assessed by pathological findings increased with age (49% in the 30- to 39-year-old group compared to 89% in those 60 years and older, p < .001). The frequency of intestinal metaplasia also increased with age (38% in the 30- to 39-year-old group compared to 82% in those 60 years and older, p < .001). In contrast, the frequency of atrophic gastritis and intestinal metaplasia was extremely low in the H. pylori seronegative group regardless of age. Mean serum gastrin level in H. pylori-positive adults was significantly greater than in those who were H. pylori-negative (114.3 +/- 11.2 compared to 65.8 +/- 6.5 pg/ml, p < .03). The serum pepsinogen I-II ratio was significantly lower in those with H. pylori infection than in those without (3.1 compared to 6.6, p < .0001).

CONCLUSIONS

These results suggest that the chronological changes in the gastric mucosa in Japanese individuals are either entirely related to H. pylori infection or the process is greatly accelerated by H. pylori infection.

Postprandial responses of liver blood flow prior to and following hepatectomy in conscious dogs

The responses of the portal and hepatic arterial blood flows to various diets and nutrients were measured simultaneously in conscious dogs prior to and following hepatic resection. Prior to hepatectomy, the increase in the portal blood flow was significantly larger in response to an elemental diet, fats, or amino acids than to glucose or water. The peak increase was 60.2 +/- 14.4 ml for water, 144.7 +/- 22.1 ml for a 150-cal elemental diet, 168.5 +/- 16.1 ml for a 300-cal elemental diet, 86.7 +/- 14.0 ml for a glucose solution, 159.3 +/- 16.7 ml for an amino acid meal, and 188.5 +/- 25.3 ml for a fat meal. Following partial hepatectomy, fats and amino acids induced an increase in the portal blood flow similar to that prior to hepatectomy. Glucose and the elemental diet, on the other hand, induced a significantly larger increase in portal blood flow following the surgery although water did not. The peak increase was 144.4 +/- 27.8 ml for glucose (166% of the peak increase prior to hepatectomy) and 221.8 +/- 32.5 ml for the 300-cal elemental diet (132%). The postprandial response of the hepatic artery to every diet was quite different among the dogs and there were no significant changes both prior to and following surgery. The different response of the portal flow to intraluminal glucose following partial hepatectomy may be due to alterations in glucose metabolism following hepatectomy. We have shown that the postprandial response of the portal blood flow varies with the type of nutrient, and it can be altered by hepatectomy.

[Pulmonary lymphangiomyomatosis with tuberous sclerosis and endolymphatic stromal myosis of the uterus]

Pulmonary lymphangiomyomatosis is a rare disorder that affects only women of reproductive age. The lung shows numerous cystic changes and striking proliferation of smooth muscle around the airways, blood vessels, and lymphatic channels. We encountered a patient with pulmonary lymphangiomyomatosis who had repeated pneumothorax and bloody sputum over 10 years. The patient also had other lesions, including intracranial calcification, renal angiomyolipoma and endolymphatic stromal myosis of the uterus. The first two findings are known as tuberous sclerosis, and lymphangiomyomatosis is considered to be a form fruste of tuberous sclerosis. However, we know of no previous reports of uterine lesions in this disease. Lymphangiomyomatosis may be a systemic disorder of smooth muscle.

Cloning of cDNA encoding for a novel isozyme of fructose 6-phosphate, 2-kinase/fructose 2,6-bisphosphatase from human placenta

Two independent cDNA clones encoding fructose 6-phosphate, 2-kinase/fructose 2,6-bisphosphatase were isolated from a human placental cDNA library. The deduced amino acid sequences showed that one of the clones, 2K-1, was almost identical to the rat testis isozyme and the other, 2K-3, was different from any known isozymes expressed in mammalian tissues. The results of Southern blot analysis suggested that clones 2K-1 and 2K-3 were encoded as single copy genes and located in different parts of the genome. Since open reading frames of the cDNA clones were not complete, we obtained the 5'-end of the clone 2K-3 cDNA using the 5'-rapid amplification of cDNA end method. The entire cDNA (HP; 1,756 bp) had a coding capacity of 519 amino acids (M(r) = 59,410), and putative phosphorylation sites for protein kinases A and C on the C terminus. Northern blot analysis using a fragment of the HP as a probe showed that a major band of 5.4 kb, significantly different in size from known isozyme mRNAs such as liver (2.1 kb), muscle (1.9 kb), heart (4.0 kb), and testis (2.0 kb), was present in poly(A)+RNA preparations of human first trimester and term placentae. These results strongly suggested that this 5.4 kb mRNA codes a novel isozyme of fructose 6-phosphate,2-kinase/fructose 2,6-bisphosphatase.

A classical strain of Vibrio cholerae with diminished ability to process the proteolytically sensitive site in the A subunit of cholera toxin

Vibrio cholerae O1, No. 31, a strain isolated from a patient with mild diarrhea, produced mainly the unnicked cholera toxin. The amount of toxin that had accumulated in the cells was approximately 200 times lower than that secreted into the culture medium. When the unnicked toxin was purified by three successive column chromatographies and then extracted from the polyacrylamide gel, the unnicked toxin showed two bands corresponding to the A and B subunits by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the A1 fragment was detected by trypsinization. Biological and enzymatic activities of the purified toxin with trypsinization were identical to those of cholera toxin from V. cholerae 569B as seen in the rabbit skin permeability test and the NAD:agmatine ADP-ribosyltransferase assay. DNA sequences of the A and B subunits were identical to those of the A- and B-subunit genes from the El Tor 2125 and classical 0395 strains, respectively. These data suggest that the wild V. cholerae strain, No. 31, produces a toxin identical to toxins previously reported in the literature and secretes it without accumulation in the cell, as is the case with other strains. However, strain No. 31's ability to nick the toxin is diminished compared with such abilities of other strains.

Human VEPs to isoluminant chromatic and achromatic sinusoidal gratings: separation of parvocellular components

To extract the responses specific to the parvocellular system (color vision and form perception) in humans, visual evoked potentials (VEPs) in response to the onset of isoluminant chromatic (red-green) and achromatic (black-white) sinusoidal gratings were recorded in 15 young adults. Chromatic stimulation evoked a characteristic negative wave (N1) with peak latencies around 120 msec. The amplitude resembled an inverse U-shaped function against the spatial frequency with a peak at 2 c/deg. In contrast, VEPs to achromatic gratings showed different spatial frequency characteristics with a peak at 5.3 c/deg. With variations in the luminous intensity ratio between the red and green gratings, N1 was seen to respond maximally to isoluminant stimulation. These results indicate that the combined use of isoluminant chromatic and achromatic patterns could stimulate the parvocellular system selectively in humans.

Improvement of hemolysis in muscle phosphofructokinase deficiency by restriction of exercise

A 29-year-old woman with muscle phosphofructokinase (PFK) deficiency had exercise intolerance, painful cramps, elevation of muscle enzyme levels in the serum and compensated hemolysis. After the restriction of exercise, the creatine kinase level and indirect bilirubin level decreased, and the reticulocyte count and haptoglobin level were normalized. It is suggested that the hemolysis which was accelerated by exercise was improved by restriction of exercise.

Value of three-dimensional spiral CT hepatic angiography

OBJECTIVE

The aim of this study was to compare with conventional angiography images the diagnostic utility of three-dimensional CT hepatic angiography (CTHA) images reconstructed from spiral CT images obtained during direct injection of contrast material into hepatic arteries.

MATERIALS AND METHODS

Three-dimensional CTHA images were reconstructed from spiral CTHA images obtained during direct hepatic arterial contrast material injection in 22 patients. We used maximum-intensity-projection (MIP) and shaded-surface-display (SSD) techniques. We compared matched pairs of MIP CTHA images and SSD CTHA images with conventional angiograms for depiction of peripheral (segmental to subsegmental order branches) and proximal (common to proper) hepatic arteries as well as for conspicuity of the entire hepatic arterial tree in 22 patients and for conspicuity of tumors, recognition of tumor sites, and depiction of tumor-feeding arteries in 21 patients with malignant liver tumors. Our evaluations were performed in a blinded fashion by two experienced radiologists, who reached a consensus. (These radiologists also counted the number of tumors depicted by each method in the 21 patients with malignant liver tumors.)

RESULTS

Depiction of peripheral and proximal hepatic arteries and conspicuity of the entire hepatic arterial tree were significantly better on conventional angiograms than on MIP CTHA images and SSD CTHA images. Conspicuity of tumors and recognition of tumor sites were significantly better on MIP CTHA images and SSD CTHA images than on conventional angiograms. Depiction of tumor-feeding arteries was significantly better on MIP CTHA images than on SSD CTHA images and conventional angiograms. For 47 malignant liver tumors, MIP CTHA images showed 40 (85%), SSD CTHA images showed 34 (72%), and conventional angiograms showed 20 (43%).

CONCLUSION

MIP CTHA images showed liver tumors, tumor sites, and tumor-feeding arteries better than conventional angiograms. MIP was the preferred method for three-dimensional CTHA analysis.

Distribution of transforming growth factor-beta and its receptors in gastric carcinoma tissue

The distribution of the three mammalian isoforms of transforming growth factor (TGF)-beta (TGF-beta 1, -beta 2, and -beta 3) as well as their signaling receptors, TGF-beta type I and type II receptors (T beta R-I and T beta R-II, respectively), in gastric carcinoma tissue was examined by immunohistochemistry using specific antibodies. Tissue specimens were obtained from 25 cases of gastric carcinoma, which were classified into two groups according to Lauren's classification, i.e. 15 cases of diffuse carcinoma and 10 cases of intestinal carcinoma. In normal gastric mucosa apart from carcinoma nests, all of TGF-beta 1, -beta 2, -beta 3, T beta R-I and T beta R-II were clearly demonstrated in fundic glands. In sharp contrast, none of them was detectable in surface mucous cells. In carcinoma cells, strong staining for TGF-beta 1, -beta 2 and -beta 3 was obtained only in diffuse-type carcinoma. In particular, carcinoma cells scattered as single cells or small nests had a tendency to show strong staining for TGF-betas. The receptors tended to be distributed concomitantly with the ligands, and diffuse-type carcinoma showed stronger receptor staining than intestinal-type carcinoma. In cancer stroma, TGF-betas and receptors were detected in both diffuse and intestinal types, but the area with positive staining was wider and more dispersed in diffuse-type carcinoma than in intestinal carcinoma. These results suggest that TGF-beta may contribute in part to the variety of histogenesis and mode of progression of gastric carcinoma.

Purification and characterization of new trehalose-producing enzymes isolated from the hyperthermophilic archae, Sulfolobus solfataricus KM1

Amylolytic activity that converts soluble starch to alpha, alpha-trehalose (trehalose), was found in the cell homogenate of the hyperthermophilic acidophilic archae, Sulfolobus solfataricus KM1. DEAE chromatography of the homogenate as well as other new reliable assay methods showed two enzymes to be essential for this activity. These enzymes, a glycosyltransferase and an amylase, were purified to homogeneity and characterized. Their molecular masses were 76 kDa and 61 kDa and activities were maximal at 70-80 degrees C and 70-85 degrees C, respectively. High thermostability was noted for each. The reaction products by the two enzymes on maltooligosaccharides were identified by 1H- and 13C-NMR spectra and HPLC analysis. The cooperative mechanism of the two enzymes was used in a new enzymatic pathway for trehalose synthesis from starch.

Differential localization of TGF-beta-precursor isotypes in psoriatic human skin

Transforming growth factor-beta (TGF-beta) can act as a multi-functional regulator of both cell growth and differentiation. Three isoforms of TGF-betas, namely TGF-beta 1 TGF-beta 2 and TGF-beta 3, have been identified in human tissues. Previously we reported the expression of TGF-beta isoforms in normal human skin. However little is known about the role of TGF-beta isoforms in the pathogenesis of psoriasis. Using the TGF-beta precursor-specific antibodies to strengthen the specificity, we studied the immunohistochemical distribution of TGF-betas 1-3 in psoriatic skin. TGF-beta 2, which was found in the intercellular space of all the layers of the epidermis in normal human skin, was decreased in the psoriatic epidermis. The intensity of immunoreactivity has the tendency to decrease in the lower epidermis rather than in the upper epidermis of the transitional lesion. In contrast, TGF-beta 3 was present in the subepidermal area of the psoriatic skin as in the normal human skin. TGF-beta 1 was observed in neither epidermis nor dermis in both normal and psoriatic skin. Since TGF-beta is a potent growth inhibitor for human keratinocytes, the decrease of TGF-beta 2 in the epidermis of psoriatic skin may contribute to epidermal hyperplasia, a hallmark of psoriasis.

Effects of pancreastatin and somatostatin on secretagogues-induced rise in intracellular free calcium in single rat pancreatic islet cells

Pancreastatin (PST) is known to inhibit glucose-stimulated insulin release both in vivo and in vitro, but it has not been determined whether PST acts directly on pancreatic B-cells and no study has been reported on the effect of PST on the intracellular free Ca2+ concentration ([Ca2+]i) in pancreatic islet cells. In the present study, by using the dissociated rat pancreatic B-cells, we examined the effects of PST on the increase in [Ca2+]i induced by several insulin secretagogues, and compared them with those of somatostatin (SRIF). PST (1-100 nM) dose-dependently inhibited the glucose-induced rise in [Ca2+]i in single pancreatic islet cells. SRIF (10 nM) also suppressed the glucose-induced rise in [Ca2+]i. These demonstrated direct inhibitory actions of PST and SRIF on the pancreatic B-cells. Acetylcholine (ACh, 10 microM) with 5.5 mM glucose induced a biphasic increase in [Ca2+]i in single islet cells. SRIF (10 nM) suppressed the second phase in [Ca2+]i increase without affecting the first phase. In contrast, PST (100 nM) had no effect on the ACh-induced response. Gastric inhibitory polypeptide (100 nM) with 5.5 mM glucose induced a rise in [Ca2+]i in single islet cells. SRIF inhibited this increase, but PST did not. Both PST and SRIF failed to affect the sustained rise in [Ca2+]i evoked by excess K+. These results suggest that PST and SRIF suppress the glucose-induced insulin secretion at least partly by inhibiting the rise in [Ca2+]i in pancreatic B-cells. Furthermore, PST may suppress the glucose-induced rise in [Ca2+]i via a mechanism different from that of SRIF.

Oral biological activities of spontaneous nitric oxide releasers are accounted for by their nitric oxide-releasing rates and oral absorption manners

We examined whether p.o. biological activities of (+/-)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (FK409), a spontaneous nitric oxide (NO) releaser, and the derivatives, i.e., (+/-)-[(E)-4-ethyl-3-[(Z)-hydroxyimino]-5-nitro-3-hexenyl]-3 - pyridinecarboxamide (FR144420) and (+/-)-N-[(E)-4-ethyl-3-[(Z)-hydroxyimino]-6-methyl-5- nitro-3-heptenyl]-3-pyridinecarboxamide (FR146801), could be accounted for by their NO-releasing rates and p.o. absorption manners. These compounds spontaneously released NO with the rates in the rank order of FK409 > FR144420 > FR146801. Total contribution of these drugs as NO donors in vivo was almost the same from the determination of urinary nitrite/nitrate (NOx) levels after p.o. administration of the compounds at 10 mg/kg to rats. Plasma NOx level after p.o. administration of FK409 at 10 mg/kg to rats reached maximal level at 120 min, and decreased gradually. On the other hand, plasma NOx levels time-dependently increased during 360 min after p.o. administration of FR144420 and FR146801 at the same dose. FK409 and FR144420 showed hypotensive effects immediately after p.o. administration at 10 mg/kg to rats, and the maximum response of FR144420 was less and the duration of the effect was longer than those of FK409, respectively. On the other hand, FR146801, which is most stable in solution, did not show any significant hypotensive effect during 240 min after p.o. administration at the same dose. In conclusion, the response and the duration of biological activity after p.o. administration of three spontaneous NO releasers can be closely accounted for by their NO-releasing rates and p.o. absorption manners.

Inflammatory cytokine production induced by an analogue of muramyl dipeptide MDP-Lys(L18) in rat macrophage cultures and dog synovial fluid

To examine the involvement of cytokines in the mechanisms of N2-[(N-acetylmuramoyl)-L-alanyl-D-isoglutaminyl]-N6-stearoyl-L-lysine, MDP-Lys(L18)-induced arthritis, we analyzed interleukin-1 (IL-1), tumor necrosis factor (TNF), colony-stimulating factor (CSF), and neutrophil chemotactic factor (NCF) by bioassays in the rat macrophage-conditioned medium (Mluminal diameter-CM) stimulated by MDP-Lys(L18) in vitro and the synovial fluid from dogs treated subcutaneously with MDP-Lys(L18) for 14 days in vivo. The dog showed arthritis characterized by swelling of the knee joint, increased synovial fluid and thickened synovial membrane, and a single subcutaneous injection of MDP-Lys(L18) was previously shown to induced synovitis in rat tarsal joint. IL-1, TNF, CSF, and NCF activities in Mluminal diameter-CM were increased by MDP-Lys(L18), while only NCF activity was detected in the dog synovial fluid. Partial purification procedures revealed that NCF in Mluminal diameter-CM was not leukotriene B4 but a protein having heparin-affinity, and, in addition, immuno-reactive IL-8 was evident to be in Mluminal diameter-CM. The NCF activity in the dog synovial fluid was not inhibited by dialysis, showing that NCF is a protein substance, possibly a chemokine. These results suggest that MDP-Lys(L18) produces a chemokine, such as IL-8, which recruits neutrophils to the synovial membrane for subsequent development of synovitis in rats and dogs.

Amount of pollen has an effect on the systemic and local levels of soluble ICAM-1 in patients with seasonal allergic rhinitis

We investigated whether the amount of antigen has an effect on the systemic and local levels of soluble ICAM-1 (sICAM-1) in patients with pollinosis, and assessed its biologic significance. The levels of subjective symptoms and sICAM-1 in sera and nasal epithelial lining fluids (ELF) from 14 subjects with pollinosis (allergic group) and eight healthy subjects (control group) were measured from pre- to postseason in 1993 (total pollen count: 10,854/cm2) and 1994 (total pollen count: 415/cm2), and the results were compared with each other among the four groups. The levels of subjective symptoms and sICAM-1 in ELF from the allergic group significantly increased during the season in both 1993 and 1994. However, there was a significant difference (P < 0.01) between the levels of those in 1993 and those in 1994 during the season. The levels of sICAM-1 in sera from the allergic group were significantly upregulated during the seasons and postseasons only in 1993, and there was a significant difference (P < 0.05) between the levels in 1993 and those in 1994 during the postseason. We conclude that amount of pollen has an influence on the local and systemic levels of sICAM-1, as well as the scores of subjective symptoms, in patients with seasonal allergic rhinitis.

Applicability of monoclonal antibody Fab fragments as a carrier of neocarzinostatin in targeting chemotherapy

Two types of fragments of MAb A7 were produced to improve the efficacy and safety in targeting chemotherapy with neocarzinostatin. In this study, 125I-labeled F(ab')2 and Fab fragments of MAb A7 and 125I-labeled MAb A7 were injected intravenously into mice with pancreatic carcinoma xenografts, and the accumulation of each antibody in the tumors was compared. A greater amount of the 125I-labeled Fab fragments of MAb A7 localized in the tumor 2 h following the injection than was observed with the other probes. Relatively less 125I-labeled MAb A7 localized in the tumor 2 h following the injection than was observed with the other two probes. Moreover, reaction of rabbit antimouse IgC with the Fc portion, which is the most immunopotent region of the Fab and F(ab')2 fragments of MAb A7 and MAb A7, was determined by ELISA; the weakest reaction was observed with the Fab fragments of MAb A7. These results suggest that the Fab fragments of MAb A7 may be more suitable carriers of an anticancer drug that is inactivated rapidly in the blood, such as NCS, in targeting chemotherapy than either intact MAb A7 or the F(ab')2 fragments of MAb A7.

Impaired endothelium-dependent vasodilation of coronary resistance vessels in hypercholesterolemic patients

To determine the relationship between hypercholesterolemia and the endothelial function of coronary resistance vessels, we studied the changes in coronary blood flow (CBF) in response to acetylcholine, an endothelium-dependent vasodilator, and adenosine, an endothelium-independent vasodilator, in patients with hypercholesterolemia (n = 17) and in control patients (n = 17). All patients had normal epicardial coronary arteries. Serial 2-min infusions of acetylcholine, at 3 micrograms/min and 30 micrograms/min, caused a dose-dependent increase in CBF in each group. The acetylcholine-induced maximal increases in CBF were inversely correlated with the serum cholesterol level (r = -0.55, p < 0.01), and were significantly smaller in the hypercholesterolemic patients than in control patients. However, the adenosine-induced increases in CBF were similar in the two groups. These results suggest that the endothelium-dependent vasodilation of resistance vessels is lessened in patients with hypercholesterolemia even before the formation of atherosclerotic stenotic lesions in epicardial coronary arteries, and that hypercholesterolemia impairs endothelium-dependent vasodilation of coronary resistance vessels.

Effect of bile duct ligation and unilateral nephrectomy on brain concentration and convulsant potential of the quinolone antibacterial agent levofloxacin in rats

To mimic the excretion route of the quinolone antibacterial agent levofloxacin (LVFX) in humans, we produced an excretion-limited (EL) model in male Sprague-Dawley rats by bile duct ligation and unilateral nephrectomy. We then examined the relationship between brain levels of LVFX and its convulsant effects in control and EL animals. Serum concentrations of LVFX in EL animals (EL + LVFX) were 2.38- and 1.59-fold and brain concentrations were 1.33- and 1.19-fold those of the controls (control + LVFX) at 30 min after a single intravenous injection of 10 and 100 mg/kg LVFX, respectively. Furthermore EL animals became more susceptible to the convulsant effect of LVFX with a 1.28-fold decrease in convulsion-inducing dose. In combination with oral pretreatment with 400 mg/kg 4-biphenylacetic acid (BPAA), convulsion-inducing doses in the control (control + LVFX + BPAA) and EL (EL + LVFX + BPAA) groups were markedly decreased by 2.25 and 9 times that of the control + LVFX group. EL operation and BPAA pretreatment slowed the elimination of LVFX in the serum and brain 4 hr later in the following order: EL + LVFX + BPAA, control + LVFX + BPAA, EL + LVFX, and control + LVFX groups. This order reflects that for the convulsion-inducing doses. These results suggest that EL rats may be a useful model for humans and that the convulsant effect of LVFX with or without BPAA arises not only from the attainment of maximum brain concentration but also from delayed disappearance from the brain.