Biomedical subjects

S Hori

Publications and source records attributed to S Hori.

At least 145 records · Page 8Linked to original sources

PubMed1998

A novel anti-platelet monoclonal antibody induces mouse platelet aggregation through an Fc receptor-independent mechanism.

Platelets are nonproliferative and terminally differentiated cells. Platelets offer an attractive model system to study the various biochemical events leading to structural and functional alterations in activated cells. When platelets are exposed to stimuli, they are activated, undergo a dramatic shape change, adhere to each other, and aggregate. Several monoclonal antibodies (mAbs) that recognize CD9, GPIIb/IIIa (alpha IIb beta 3 intergrins), or GPIV are known to stimulate human platelet aggregation. However, no mAbs able to induce aggregation of mouse platelets have been reported. We have established an anti-mouse platelet mAb (AIP21) that can promote mouse platelet aggregation by itself. Because mouse platelets did not express the Fc receptor (FcR, CD32) on their surfaces and because AIP21 is an IgM subclass, AIP21 might promote platelet aggregation through an FcR-independent mechanism. We could not identify the antigen recognized by AIP21, but flow cytometric analysis revealed that it was not identical to CD9, GPIV, or integrins (i.e., alpha IIb, alpha v, alpha 5, alpha 6, beta 1, and beta 3 integrins). During the aggregation of mouse platelets mediated by AIP21, several 50-68-kDa proteins are rapidly phosphorylated at tyrosine residues. This phosphorylation by AIP21 was dose-dependent and did not require plasma components. We identified the 52-kDa phosphorylated protein as Shc. These results indicate that AIP21 could be useful for investigating the mechanisms of mouse platelet aggregation.

Animals↗

PubMed1998

Conduction pathways of motor evoked potentials following transcranial magnetic stimulation: a rodent study using a "figure-8" coil.

We have examined the conduction pathways of motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation, and their correlation with locomotor function in rats. MEPs were concomitantly recorded from the spinal cord (sMEPs) and the limb muscles (mMEPs) before and after various spinal tract ablations. Motor function was also examined using an inclined plane test. sMEPs were composed of four negative peaks (N1-N4) and mMEPs of high-voltage, biphasic waves. Ventral funiculus transection reduced the N1-N3 peaks and abolished mMEPs. Contrarily, dorsal funiculus transection including the pyramidal tract did not alter these MEPs. Motor performance on an inclined plane was worse after ventral funiculus transection than after other transections. These findings indicate that, in rats, the N1-N3 peaks of magnetic sMEPs conduct ventral funiculus activity, and that magnetic mMEPs mainly reflect extrapyramidal activities and are correlated with locomotor function.

Animals↗

PubMed1998

Involvement of gp130-mediated signaling in pressure overload-induced activation of the JAK/STAT pathway in rodent heart.

Previously, we showed that the JAK/STAT pathway was activated in pressure-overloaded rat heart, and that angiotensin II was partially involved in this activation. The present study was designed to investigate whether gp130-mediated signaling is involved in this activation, and if so, which interleukin (IL)-6 family cytokine is involved. Pressure overload was produced by ligation of the abdominal aorta of Wistar rats or ICR mice. IP-Western blot was performed to detect tyrosine phosphorylation of STATs, gp130, and the association of gp130 with JAK kinases. The serum concentration of IL-6 was measured by enzyme-linked immunosorbent assay. Expression of IL-6, IL-11, leukemia inhibitory factor (LIF), ciliary neurotrophic factor (CNTF), oncostatin M (OSM), and cardiotrophin-1 (CT-1) mRNA was quantitated. After pressure overload, rapid phosphorylation of STAT1 and STAT3 was observed at 5 min, STAT1 was rephosphorylated at 60 min, and intense phosphorylation of STAT3 was observed at 60 min. Both the phosphorylation of gp130 and the association of gp130 with JAK1 and JAK2 were increased after pressure overload. IL-6 was significantly increased by two-fold in the pressure-overloaded rats. Only CT-1 mRNA expression could be detected by Northern blot, and it increased after pressure overload. Reverse transcription-polymerase chain reaction revealed that IL-6 mRNA expression was increased 9.5-fold. IL-11, LIF, CNTF, and OSM expression were unaffected by pressure overload. These results suggested that gp130-mediated signaling was involved in the pressure overload-induced activation of the JAK/STAT pathway, and that IL-6 and CT-1 might be involved in this activation.

Animals↗

PubMed1998

Pharmacokinetics of nimustine, methotrexate, and cytosine arabinoside during cerebrospinal fluid perfusion chemotherapy in patients with disseminated brain tumors.

OBJECTIVE: This study was conducted to evaluate the pharmacokinetics of anticancer drugs in cerebrospinal fluid (CSF) perfusion chemotherapy. METHODS: We administered CSF perfusion chemotherapy with nimustine (ACNU), methotrexate (MTX), and cytosine arabinoside (Ara-C) to three patients with disseminated malignant brain disease. The drugs were infused via Ommaya's reservoirs to the lateral ventricle and removed by drainage from the temporal lobe or lumbar spine. CSF and plasma concentrations of the anticancer drugs were determined by high-performance liquid chromatography and fluorescence polarization immunoassay. RESULTS: The concentrations of anticancer drugs in the discharged CSF peaked about 40 min after the start of a 1-h CSF perfusion. After the perfusion, the drug level in CSF decreased exponentially in a monophasic manner. ACNU and Ara-C were not detectable in the discharged CSF in the temporal lobe at 6 h and 48 h after perfusion, respectively, but MTX was detectable at 48 h. The maximum concentration ratio of anticancer drugs and the duration of perfusion were inversely correlated. The plasma concentrations of anticancer drugs were much lower than those in CSF. The half-life of ACNU was very short (0.2-1.1 h), whereas the half-lives of MTX and Ara-C were relatively long (2.81-13.5 h and 1.84 6.25 h, respectively). The half-lives of the anticancer drugs in CSF tended to decrease with repeated CSF perfusion chemotherapy. CONCLUSION: Results suggest that CSF perfusion chemotherapy enables a high concentration of anticancer drug to be administered for dissemination in the spinal cord within a short period of time, with minimal adverse effects.

Adult↗

PubMed1998

Effects of decreased plasma glutamine concentrations on peripheral lymphocyte proliferation in rats.

The relationship between exercise-induced lowering of plasma glutamine concentrations and proliferation of peripheral lymphocytes was investigated in male Wistar rats. The T-lymphocyte proliferative responses to the mitogen, concanavalin A, were determined by incorporation of radiolabelled thymidine into the DNA in vitro. The rats ran 2 h x day(-1), 6 days x week(-1) for 4 weeks. Analysis immediately after the final period of exercise showed T-lymphocyte proliferation to be significantly depressed, together with a marked decrease in plasma glutamine concentrations. There were also significant increases in serum corticosterone concentrations immediately after exercise. However, following 24-h recovery, this exercise-induced immunosuppression was not statistically significant when compared with the age-matched control group. In the second experiment, in order to clarify the importance of glutamine for immunological function in vivo, methionine sulfoximine, an effective inhibitor of glutamine synthetase was injected intraperitoneally (12.5 mg x kg body mass[-1]). Plasma glutamine concentrations were decreased 4 h after the injection, compared with the placebo control group, and this resulted in a significant decrease in the rate of T-lymphocyte proliferation. This treatment had no effects on serum corticosterone concentrations. These results would suggest that the chronic exercise-induced reduction in proliferation of peripheral T-lymphocytes is a transient reversible phenomenon, which returns to normal levels within 24 h of the final training period. It is also conceivable that this exercise-induced immunosuppression is associated with a decrease in circulating glutamine concentrations.

Amino Acids↗

PubMed1998

Effects of the endothelin receptor antagonist TAK-044 on hepatocyte element alterations in the ischemic-reperfused liver in Beagle dogs.

BACKGROUND/AIMS: This study was designed to investigate elemental alterations of subcellular organelles (cytoplasm, nucleus, mitochondria) after ischemia of the liver, and the effects of the pre-ischemic administration of an endothelin ETA/ETB receptor antagonist (TAK-044) on subcellular elements. METHODS: We determined serial changes in subcellular elements by X-ray microanalysis using liver biopsy specimens, and we compared the liver functions of a control and a TAK-044-treated group of Beagle dogs, before and after 70% partial ischemia (60 min). TAK-044 was given intravenously at a dose of 3 mg/kg before ischemia. RESULTS: In the control, the Ca concentration in the cytoplasm showed a slight increase after ischemia and a marked increase immediately after reperfusion. It returned to approximately pre-ischemic levels at 6 h after reperfusion. In contrast, in the TAK-044 group, the increase was significantly suppressed. The changes in Na and Cl, which increased in parallel with Ca, were also suppressed in the TAK-044 group. The alterations in K were opposite to those Ca. These changes were also suppressed to a significant degree in the TAK-044 group. Elemental alterations in the nucleus and mitochondria were similar to those in the cytoplasm in both the control and TAK-044 groups. The changes in the liver functions and the electron microscopic findings supported the differences in serial changes in subcellular elements between the two groups. CONCLUSIONS: TAK-044 exhibited a hepatoprotective effect on ischemia-reperfusion injury from the aspect of subcellular elemental dynamics and liver functional and morphologic changes.

Animals↗

PubMed1998

Effectiveness of kampo medicine (sai-boku-to) in treatment of patients with glossodynia.

OBJECTIVE: The purpose of this study was to evaluate the usefulness of a Kampo medicine (Sai-boku-to) for treatment of patients with glossodynia. STUDY DESIGN: Sai-boku-to or an antianxiety drug (diazepam) with vitamin B complex was administered orally for 3 months to each of 200 patients with glossodynia. Clinical examination evaluated the following subjective symptoms: pain, burning sensation, and discomfort. Effectiveness was evaluated as follows: "markedly effective," all 3 symptoms disappeared; "effective," pain improved; "ineffective," no improvement in pain. RESULTS: The effective rates were 70% after 1 month, 85% after 2 months, and 92% after 3 months of administration of Sai-boku-to (the Kampo group) and 74% after 1 month, 71% after 2 months, and 69% after 3 months of administration of the antianxiety drug with vitamin B complex (the control group). No significant side effect was noted in the Kampo group, but sleepiness was recorded in 33 cases in the control group. CONCLUSIONS: The results indicate that Sai-boku-to may be a clinically useful medicine for the long-term treatment of patients with glossodynia.

Adult↗

PubMed1998

Effect of serotonin on ouabain-sensitive, K+-dependent, p-nitrophenylphosphatase activity in strial marginal cells of normal and reserpinized guinea pigs.

Na+,K+-ATPase activity is abundant on the basolateral infoldings of the strial marginal cells and contributes to the maintenance of the characteristic electrolyte composition of the endolymph. However, the stria vascularis of the cochlea is known not to be innervated. In order to clarify its humoral regulation by serotonin, the K+-p-nitrophenylphosphatase activity of strial marginal cells was investigated with a cerium-based method in normal guinea pigs and in guinea pigs treated with reserpine, 5-hydroxytryptamine or reserpine plus 5-hydroxytryptamine. K+-p-nitrophenylphosphatase activity was almost completely depressed 3-20 days after reserpine administration. Ten days after reserpinization, followed by repeated 5-hydroxytryptamine treatment, the enzyme activity was detectable. These results suggest that 5-hydroxytryptamine increases the phosphatase activity. Thus, the function of the stria vascularis in producing cochlear endolymph may be regulated by 5-hydroxytryptamine.

4-Nitrophenylphosphatase↗

PubMed1998

Expression of multidrug resistance protein gene in patients with glioma after chemotherapy.

Two different ATP-binding membrane glycoproteins, the 170 kDa P-glycoprotein (P-gp) and the 190 kDa multidrug resistance protein (MRP), are involved in the acquisition of multidrug resistance phenotypes in cancer cells. Overexpression of P-gp is often observed in various human tumors when treated with anticancer agents. In this study, we asked whether MRP was overexpressed in human gliomas after cancer chemotherapy. We investigated expression of MRP and P-gp before and after chemotherapy in tumor samples from patients with glioma. MRP expression was observed in 16 (70%) of 23 untreated patients, and the proportion of MRP-positive cells in the whole cell population ranged from 3 to 32% in the 16 MRP-positive patients. P-gp-positive tumors were observed in 4 (18%) of 23 patients, and the proportional rates of P-gp-positive cells in the whole cell population ranged from 4 to 23%. The proportional rate of MRP-positive or P-gp-positive glioma cells increased after chemotherapy when compared with that before chemotherapy in all patients examined. We could observe no statistically significant correlation between expression of MRP or P-gp and tumor grade. These results suggest that MRP as well as P-gp may be involved in acquired or intrinsic drug resistance in human glioma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1998

Determination of N-methylcarbamate pesticides in foods using an accelerated solvent extraction with a mini-column cleanup.

Residual N-methylcarbamate pesticides in food were determined by accelerated solvent extraction (ASE) and HPLC with post-column fluorescence. Pesticides were extracted with acetonitrile at 100 degrees C under 2000 psi pressure in less than 20 min. Extracts were cleaned-up with a carboxylic acid mini-column eluted with 10% or 30% acetone in hexane. Eight foods were spiked with 17 pesticides at 0.2 ppm. The average recoveries of these pesticides were 70-100% and the relative standard deviations were < 10%. These results suggested that ASE can be used to extract residues of N-methylcarbamate pesticides in foods.

Carbamates↗

PubMed1998

Motor discoordination and increased susceptibility to cerebellar injury in GLAST mutant mice.

To study the function of GLAST, a glutamate transporter highly expressed in the cerebellar Bergmann astrocytes, the mouse GLAST gene was inactivated. GLAST-deficient mice developed normally and could manage simple coordinated tasks, such as staying on a stationary or a slowly rotating rod, but failed more challenging task such as staying on a quickly rotating rod. Electrophysiological examination revealed that Purkinje cells in the mutant mice remained to be multiply innervated by climbing fibres even at the adult stage. We also found that oedema volumes in the mutant mice increased significantly after cerebellar injury. These results indicate that GLAST plays active roles both in the cerebellar climbing fibre synapse formation and in preventing excitotoxic cerebellar damage after acute brain injury.

ATP-Binding Cassette Transporters↗

PubMed1998

Purification and characterization of myonase from X-chromosome linked muscular dystrophic mouse skeletal muscle.

A chymotrypsin-like proteinase, designated myonase, was successfully purified to homogeneity from X-chromosome linked muscular dystrophic mouse skeletal muscle by affinity chromatography on agarose conjugated with lima bean trypsin inhibitor as ligand. The molecular mass of the purified myonase was determined to be 26 kDa by SDS-PAGE and to be 25,187 Da by mass spectrometry. The native enzyme is a single chain molecule and a monomeric protein without sugar side-chains. The nucleotide sequence of myonase mRNA is similar to mouse mast cell proteinase 4 (MMCP-4) cDNA. This is the first report of a native enzyme whose amino acid sequence closely corresponds to MMCP-4 cDNA. Myonase has chymotrypsin-like activities and hydrolyzes the amide bonds of synthetic substrates having Tyr and Phe residues at the P1 position. Myonase is most active at pH 9 and at high concentration of salts. Myonase preferentially hydrolyzes the Tyr4-Ile5 bond of angiotensin I and the Phe20-Ala21 bond of amyloid beta-protein, and it is less active towards the Phe8-His9 bond of angiotensin I and the Phe4-Ala5 and Tyr10-Glu11 bonds of amyloid beta-protein. Myonase is completely inhibited by such serine proteinase inhibitors as chymostatin, diisopropylfluorophosphate and phenylmethylsulfonyl fluoride, but not by p-tosyl-L-phenylalanine chloromethyl ketone, p-tosyl-L-lysine chloromethyl ketone, pepstatin, E-64, EDTA, and o-phenanthroline. It is also inhibited by lima bean trypsin inhibitor, soy bean trypsin inhibitor, and human plasma alpha1-antichymotrysin. These properties match those of chymase, but unlike chymase, myonase does not interact with heparin in the regulation of its activity. Myonase was immunohistochemically localized in myocytes, but not in mast cells.

Amino Acid Sequence↗

PubMed1998

Immunoreactive endothelin levels in the vitreous fluid are decreased in diabetic patients with proliferative retinopathy.

Endothelin (ET) plays an important role in the pathogenesis of various cardiovascular lesions. To elucidate the pathophysiologic significance of ET in the development of diabetic retinopathy, we determined immunoreactive ET levels in the vitreous fluid collected during vitrectomy in seven patients with non-insulin dependent diabetes mellitus with proliferative diabetic retinopathy and in 10 nondiabetic subjects as controls. Immunoreactive vitreous ET levels in diabetic patients with proliferative retinopathy (7.5 +/- 3.4 pg/ml, mean +/- SD) were significantly lower than those in the nondiabetic subjects (55.0 +/- 38.1 pg/ml; p < 0.005). The decreased rather than increased immunoreactive ET levels may simply reflect severe endothelial injury to the retinal vessels caused by diabetic microangiopathy rather than an important role in diabetic retinopathy.

Blood Pressure↗

PubMed1998

Inhibition of nitric oxide synthesis aggravates myocardial ischemia in hemorrhagic shock in constant pressure model.

In hemorrhagic shock (HS), nitric oxide synthase (NOS) inhibitor is known to increase blood pressure and prolong survival time. On the other hand, NOS inhibitor decreases coronary flow and worsens myocardial ischemia. Therefore, we hypothesized that the beneficial effect of NOS inhibitor is attributable to the increased coronary perfusion pressure and that it outcompetes the coronary vasodilating effects of nitric oxide. To investigate the direct effect of NOS inhibitor on the regulation of coronary circulation and the induction of myocardial ischemia in HS, we used a canine model at a constant aortic pressure of 40 mmHg with an aortic reservoir. In seven dogs, intravenous administration of Nomega-nitro-L-arginine methyl ester (L-NAME, 30 mg/kg) at 10 min after induction of HS increased both systemic and coronary vascular resistances and further increased the serum catecholamine concentration at 10 min after L-NAME. In another 14 dogs, the beating hearts were rapidly cross-sectioned (120 ms) and freeze clamped (-190 degrees C) by a specially developed sampling device after 10 min of HS. Transmurally distributed myocardial ischemia was visualized by the enhanced reduced nicotinamide adenine dinucleotide fluorescence, which was significantly increased with L-NAME (n=7). Chemical analysis revealed a decrease in the myocardial ATP concentration with L-NAME in the subendocardial ischemic region in HS. In conclusion, with the use of an aortic reservoir to keep the aortic pressure constant in HS, NOS blockade significantly worsened myocardial ischemia by decreasing coronary flow and augmenting the serum catecholamine concentration.

Adenosine Triphosphate↗

PubMed1998

Clinical efficacy of the FLUTTER device for airway mucus clearance in patients with diffuse panbronchiolitis.

Expectoration of mucus is important in preventing the development of airway inflammation in patients with diffuse panbronchiolitis (DPB). To evaluate the clinical efficacy of the FLUTTER device in clearing mucus from the airways of patients with DPB who have difficulty expectorating, we assessed pulmonary function and symptoms in patients treated with FLUTTER. Eight patients in a stable clinical condition with DPB were included in the study. The study was divided into two consecutive, 1-week periods. The initial week was an observation week. During the following week, patients used FLUTTER four times daily. Expectorated sputum was collected in a container and weighed every day during 2 weeks. Pulmonary function, partial oxygen pressure and partial carbon dioxide pressure in arterial blood were measured in all patients on the last day of the observation week and the FLUTTER treatment week. A symptom score for difficulty of expectoration was determined by questionnaire. A pneumothorax developed in one patient during using FLUTTER. The mean daily sputum weight and peak expiratory flow rate increased significantly after treatment with FLUTTER ( P< 0.04 and P< 0.02, respectively). Symptom score improved significantly after using FLUTTER ( P< 0.02). We conclude that the use of FLUTTER is effective in clearing mucus from the airways. However, the development of a pneumothorax may complicate use of the procedure in some cases.

Adult↗

PubMed1998

Both ET(A) and ET(B) receptors are involved in mitogen-activated protein kinase activation and DNA synthesis of astrocytes: study using ET(B) receptor-deficient rats (aganglionosis rats).

Endothelin (ET) is known to be a potent mitogen in astrocytes. However, the contribution and signalling pathway of ET(A) and/or ET(B) receptor to the proliferation of astrocytes remain unclear. We investigated ET-induced DNA synthesis in astrocytes using ET(B) receptor-deficient mutant rats (aganglionosis rats: sl/sl). Western blotting with anti-ET receptor subtype-specific antibodies and Scatchard analysis of binding revealed that ET(B) receptor expression in astrocytes depended on gene dosage (+/+: sl/+: sl/sl=2: 1:0), whereas ET(A) receptor expression was unchanged among the three genotypes. ET-1 (10 nM) stimulated [3H]thymidine incorporation and mitogen-activated protein kinase (MAP kinase) activity not only in +/+ via both ET(A) and ET(B) receptors, but also in sl/sl astrocytes via ET(A) receptor with about half the extent of those observed in +/+ astrocytes. Treatment with pertussis toxin (PTX) suppressed the ET-1-induced increases in the incorporation and MAP kinase activity in +/+, but not sl/sl astrocytes, indicating that the ET(B) receptor-, but not the ET(A) receptor-, mediated pathway to DNA synthesis involves PTX-sensitive G proteins, e.g. Gi and/or Go (Gi/o). In +/+ astrocytes, ET-1 (1 nM) stimulated cAMP accumulation, and the ET(B) receptor-selective agonist IRL 1620 (1 nM) suppressed 10 microM forskolin-induced cAMP accumulation, suggesting Gs coupling to the ET(A) receptor and Gi/o coupling to the ET(B) receptor. On the other hand, ET-1 did not increase cAMP accumulation in sl/sl astrocytes, although ET-1 (1 nM) suppressed the forskolin-induced response, suggesting Gi/o coupling to the ET(A) receptor. Our results suggest the possibility that the selectivity of G protein for ET(A) receptor is changed from Gs to Gi/o in ET(B) receptor-deficient astrocytes.

Amino Acid Sequence↗

PubMed1998

Antibacterial activity of gatifloxacin (AM-1155, CG5501, BMS-206584), a newly developed fluoroquinolone, against sequentially acquired quinolone-resistant mutants and the norA transformant of Staphylococcus aureus.

Alternate mutations in the grlA and gyrA genes were observed through the first- to fourth-step mutants which were obtained from four Staphylococcus aureus strains by sequential selection with several fluoroquinolones. The increases in the MICs of gatifloxacin accompanying those mutational steps suggest that primary targets of gatifloxacin in the wild type and the first-, second-, and third-step mutants are wild-type topoisomerase IV (topo IV), wild-type DNA gyrase, singly mutated topo IV, and singly mutated DNA gyrase, respectively. Gatifloxacin had activity equal to that of tosufloxacin and activity more potent than those of norfloxacin, ofloxacin, ciprofloxacin, and sparfloxacin against the second-step mutants (grlA gyrA; gatifloxacin MIC range, 1.56 to 3.13 microg/ml) and had the most potent activity against the third-step mutants (grlA gyrA grlA; gatifloxacin MIC range, 1.56 to 6.25 microg/ml), suggesting that gatifloxacin possesses the most potent inhibitory activity against singly mutated topo IV and singly mutated DNA gyrase among the quinolones tested. Moreover, gatifloxacin selected resistant mutants from wild-type and the second-step mutants at a low frequency. Gatifloxacin possessed potent activity (MIC, 0.39 microg/ml) against the NorA-overproducing strain S. aureus NY12, the norA transformant, which was slightly lower than that against the parent strain SA113. The increases in the MICs of the quinolones tested against NY12 were negatively correlated with the hydrophobicity of the quinolones (correlation coefficient, -0.93; P < 0.01). Therefore, this slight decrease in the activity of gatifloxacin is attributable to its high hydrophobicity. Those properties of gatifloxacin likely explain its good activity against quinolone-resistant clinical isolates of S. aureus harboring the grlA, gyrA, and/or norA mutations.

Anti-Infective Agents↗

PubMed1998

Pharmacokinetics of intra-arterially administered pirarubicin in plasma and cerebrospinal fluid of patients with glioma.

The present paper investigates the pharmacokinetics of pirarubicin (THP) in the plasma and cerebrospinal fluid (CSF) of two patients with glioma during hyperosmotic disruption of the blood-brain barrier (HODBBB) and intra-arterial combination chemotherapy. A 42-year-old Japanese man (patient A) with glioblastoma and a 21-year-old Japanese woman (patient B) with astrocytoma received a course of HODBBB and intra-arterial combination chemotherapy with THP, methotrexate, peplomycin, and vindesine. Patient A was initially administered mannitol, followed by the infusion of anticancer drugs into the right internal carotid artery. Patient B was initially administered mannitol, followed by the infusion of anticancer drugs into the right internal carotid artery and, immediately thereafter, into the right vertebral artery. Samples of blood and of CSF in the brain ventricle were obtained. THP concentration was measured by HPLC, and the pharmacokinetic parameters of this drug were estimated in plasma and CSF. In both patients, the plasma concentration of THP peaked at the end of infusion, then decreased in a bi-exponential decay pattern during the remainder of the treatment period. THP was detectable in CSF beginning 1.0 h after the initiation of infusion, then was slowly eliminated from the ventricle. The maximum CSF concentration of THP was 0.97% of plasma in patient A and 0.89% in patient B. The CSF AUC of THP was 28.4% of plasma in patient A and 13.1% in patient B.

Adult↗