[Anuria due to bilateral renal artery spasm during hysterectomy and oophorectomy]

A decrease in urinary volume during surgery is often encountered. Usually it can be treated with intravenous fluid or diuretics. We here report a rare case of intraoperative anuria in which renal blood flow ceased totally. The patient was 36 year old female (166 cm 50 kg), who was admitted for a investigations of long-term severe hypertension of unknown origin. Radiographic examination showed no adrenal tumor but a right ovarian cyst was found and suspected to be malignant, for which oophorectomy was indicated. After epidural catheterization, general anesthesia was induced by intravenous propofol and vecuronium, and maintained with epidural lidocaine and the inhalation of isoflurane and nitrous oxide mixed with oxygen. During surgery, urinary outflow decreased gradually leading to total anuria, which was resistant to intravenous fluid and furosemide. Intraoperative pyelography was performed and both kidneys and urinary tracts were not visualized. After the surgery, when the patient returned to the ward, urine began to flow. Postoperative pathological examination of the removed ovary showed a presence of renin excreting tumor cells. The anuria was considered to be the result of transient spastic obstruction of bilateral renal arteries, presumably in response to a high level of plasma renin.

[Remission due to CYVADIC chemotherapy of primary leiomyosarcoma derived from mesentelium of the sigmoid colon: a case report]

We report a case of leiomyosarcoma of mesenthelium origin, which was successfully treated with a combination of cyclophosphamide, vincristine, adriamycin and dacarbazine (CYVADIC). A 56-year-old woman received three courses of adjuvant CYVADIC chemotherapy after initial surgery consisting of tumorectomy, sigmoidectomy, descending colostomy, cystectomy and ureterostomy. A six-month disease-free period was attained obtained. A recurrent tumor showed remarkable reduction after three courses of CYVADIC chemotherapy. This case may be the first report of successful chemotherapy against a leiomyosarcoma of mesenthelium origin in Japan.

Detection of bikunin mRNA in limited portions of rat brain

Tissue distribution of bikunin mRNA, which encodes a Kunitz-type serine protease inhibitor of the inter-alpha-inhibitor family (IalphaI), was studied in rats and mice by the reverse-transcripsion polymerase chain reaction (RT-PCR). We found that the liver as well as other tissues, such as the kidney, testis and adrenal gland, expressed bikunin mRNA. Although signals of bikunin mRNA were faint in the whole brain of rats and mice, distinct signals were found in limited portions of rat brain, such as the hippocampus, cerebral cortex and pituitary, but undetectable in cerebellum, medulla oblongata, hypothalamus, striatum, midbrain and choroid plexus. In three distinct types of cells, such as neurons, astrocytes and meningeal cells, in primary cultures isolated from the cerebral cortex and meninges of 1-day-old newborn rats, only neurons positively expressed bikunin mRNA. These results suggest that, in addition to peripheral tissues, neurons in the hippocampus and cerebral cortex produce bikunin, suggesting a potential role of bikunin/IalphaI family in these brain regions.

[The enhancement of formalin induced agitation behavior by intrathecal administration of prostaglandin E1]

The spinal action of pro-inflammatory agent, prostaglandin E1 (PGE1) was investigated in rats, using formalin test. Sprague-Dawley rats were implanted with chronic intrathecal catheters. PGE1 0.25 microgram or 2.5 micrograms injected intrathecally. Ten minutes later, 5% formalin 50 microliters was injected to the dorsum of one hindpaw. For the time-response analysis, the total number of flinches were counted and expressed as responses per minute for each rat. For the dose response analysis, the cumulative responses per minute over the first 5 min (phase 1) and the interval 10-60 min (phase 2) following the formalin injection were calculated for each rat. PGE1 2.5 micrograms produced a significant increase of flinching in both phase 1 and phase 2. Dose dependent increase of flinching was seen only in the phase 2. Touch evoked allodynia was observed after the injection of PGE1 2.5 micrograms, which lasted about 50 minutes. The enhanced flinches induced by intrathecal PGE1 were antagonized by the coadministration of MK-801, hemoglobin or methylene blue. Allodynia was antagonized only by coadministration of methylene blue. These results indicate that hyperalgesia induced by spinal PGE1 in both phase 1 and phase 2 of the formalin test involves an increased release of glutamate and the activation of NMDA receptor in the spinal cord. The mechanism of allodynia observed in the rats given high dose of PGE1 differs from that of hyperalgesia.

Effects of aluminum on plasma membrane as revealed by analysis of alkaline band formation in internodal cells of Chara corallina

To study the mechanism of aluminum toxicity in plant cells, the effects of aluminum on alkaline band formation were analyzed in the internodal cells of Chara. After cells were treated with AlCl3, they were examined for their capacity to develop alkaline bands. Treating cells with AlCl3 medium at pH 4.5 completely inhibited alkaline band formation. When either CaCl2 or malic acid was added to the AlCl3 medium (pH 4.5), it did not produce an ameliorative effect, whereas addition of both CaCl2 and malic acid induced a significant ameliorative effect. It was found that treatment at pH 4.5 in the absence of AlCl3 strongly inhibited alkaline band formation. This inhibition by the low pH (4.5) treatment was effectively ameliorated by CaCl2. At higher pH (5.0), malic acid alone produced a significant ameliorative effect on aluminum inhibition of alkaline band formation, but CaCl2 did not. Recovery from aluminum inhibition was also studied. When cells treated with AlCl3 at pH 4.5 were incubated in artificial pond water, they could not recover the capacity to develop alkaline band. When either malic acid or CaCl2 was added to artificial pond water, cells recovered their alkaline band formation. It was concluded that one of the primary targets of aluminum is the plasma membrane and that aluminum affects the plasma membrane from the cell exterior at the beginning of the treatment (within 24 h). It was also suggested that the aluminum treatment impairs the HCO3- influx mechanism but not the OH- efflux mechanism.

Molecular characterization of the hyperpolarization-activated cation channel in rabbit heart sinoatrial node

We cloned a cDNA (HAC4) that encodes the hyperpolarization-activated cation channel (If or Ih) by screening a rabbit sinoatrial (SA) node cDNA library using a fragment of rat brain If cDNA. HAC4 is composed of 1150 amino acid residues, and its cytoplasmic N- and C-terminal regions are longer than those of HAC1-3. The transmembrane region of HAC4 was most homologous to partially cloned mouse If BCNG-3 (96%), whereas the C-terminal region of HAC4 showed low homology to all HAC family members so far cloned. Northern blotting revealed that HAC4 mRNA was the most highly expressed in the SA node among the rabbit cardiac tissues examined. The electrophysiological properties of HAC4 were examined using the whole cell patch-clamp technique. In COS-7 cells transfected with HAC4 cDNA, hyperpolarizing voltage steps activated slowly developing inward currents. The half-maximal activation was obtained at -87.2 +/- 2.8 mV under control conditions and at -64.4 +/- 2.6 mV in the presence of intracellular 0.3 mM cAMP. The reversal potential was -34.2 +/- 0.9 mV in 140 mM Na+o and 5 mM K+o versus 10 mM Na+i and 145 mM K+i. These results indicate that HAC4 forms If in rabbit heart SA node.

Transport of rhodamine 123, a P-glycoprotein substrate, across rat intestine and Caco-2 cell monolayers in the presence of cytochrome P-450 3A-related compounds

Effects of cytochrome P-450 3A- and P-glycoprotein (P-gp)-related compounds, erythromycin, midazolam, ketoconazole, verapamil, and quinidine, on transport of rhodamine 123 (Rho-123), a P-gp substrate, were studied in rat intestine and in Caco-2 cells. Ileum was mainly used in rat studies because this segment showed greater P-gp-mediated Rho-123 transport. In an in vitro everted rat ileum, all the compounds examined significantly inhibited the transport of Rho-123 from serosal to mucosal surfaces across the intestine, with different inhibitory potencies among these compounds. In an in vivo rat study, the exsorption of Rho-123 from blood to the intestinal lumen, which was evaluated as exsorption clearance of Rho-123 under a steady-state plasma concentration of Rho-123, was also inhibited when these compounds were added to the intestinal lumen. Similarly, transepithelial transport of Rho-123 from the basolateral to apical side across Caco-2 cell monolayers was inhibited by these compounds. A linear relationship was observed in their inhibitory potencies on Rho-123 transport between in vitro and in vivo studies using rat ileum and between studies with rat ileum and Caco-2 cells. P-gp-mediated transport across the intestine was found to be inhibited not only by P-gp-related but also by all the cytochrome P-450 3A-related compounds examined. Within experimental error, the relative inhibitory potencies were the same between the studies with rat ileum (in vivo, in vitro) and those with Caco-2 cells. Thus, it is suggested that the function of P-gp and its sensitivity to these drugs may be similar in rat intestine and Caco-2 cells.

Tissue response of a small saccular aneurysm after incomplete occlusion with a Guglielmi detachable coil

A 49-year-old woman had a small saccular aneurysm that was incompletely occluded with a Guglielmi detachable coil (GDC). She died from rupture of another aneurysm 42 days after the treatment. Autopsy for the embolized aneurysm revealed no neoendothelium at the aneurysmal neck, but an organized thrombus was observed limited to the periphery of the aneurysmal lumen. Although isolation of the aneurysm was not apparent, loose embolization with this method may help to reinforce the aneurysmal wall.

In-vivo and in-vitro metabolic clearance of midazolam, a cytochrome P450 3A substrate, by the liver under normal and increased enzyme activity in rats

The metabolic clearance of midazolam, a cytochrome P450 (CYP) 3A substrate, by the liver under normal and increased enzyme activity in rats was determined in-vivo and in-vitro to elucidate the reproducibility of the in-vivo hepatic extraction ratio of midazolam from the in-vitro study. The hepatic enzyme activity was modified by pretreating rats with a CYP inducer such as dexamethasone and clotrimazole. The in-vivo hepatic extraction ratio (ERh,obs) of midazolam under a steady-state plasma concentration (approx. 3 nmolmL(-1)) in untreated (control) rats was 0.864. This value increased to 0.984 in dexamethasone-pretreated rats and to 0.964 in clotrimazole-pretreated rats. The in-vitro hepatic intrinsic clearance (CL(int,in-vitro)), expressed as mLmin(-1) (mg microsomal protein)(-1), of midazolam was estimated as Vmax (Km)(-1) by in-vitro metabolism studies using liver microsomes. The CL(int,in-vitro) value was converted to the CL(int,cal) value, expressed as mLmin(-1)kg(-1), by considering the microsomal protein content (g liver)(-1) and the microsomal protein content (g liver)(-1)kg(-1). The estimated CL(int,cal) value was then converted to the ERh value (ER(h,cal)) according to the well-stirred, the parallel-tube and the dispersion models. The ERh(h,cal) values obtained by the parallel-tube model were in good agreement with corresponding in-vivo ERh(h,obs) values. In conclusion, it was demonstrated that high hepatic clearances of midazolam under normal and increased CYP3A activity were reasonably predicted from in-vitro metabolism studies using liver microsomes.

Role of P-glycoprotein in distribution of rhodamine 123 into aqueous humor in rabbits

PURPOSE

Examination of the contribution of functional P-glycoprotein (P-gp), an ATP-dependent efflux pump, in blood-aqueous barrier in rabbits.

METHODS

Rhodamine-123 (Rho-123), a P-gp substrate, was administered intravenously via the marginal ear vein of rabbits. Rhodamine B (Rho-B), an analogue of Rho-123, was also injected with the same dose, as a reference compound. Quinidine at different concentrations was applied topically to the corneal surface by eye drops prior to the intravenous administration of a Rho compound. The aqueous distribution (a ratio of concentration in aqueous humor to that in plasma) of these Rho compounds was analyzed in relation to the aqueous concentration of quinidine. Transport study across Caco-2 cell monolayers was carried out to examine the involvement of P-gp in Rho-B transport.

RESULTS

It was proved that Rho-B is not a P-gp substrate by a transport study across Caco-2 cell monolayers, in contrast to Rho-123 (a P-gp substrate). The aqueous distribution of Rho-123 given intravenously was significantly lower than that of Rho-B. Topical quinidine (a P-gp inhibitor) markedly increased the aqueous distribution of Rho-123, depending on the aqueous concentrations of quinidine, though it did not affect the aqueous distribution of Rho-B.

CONCLUSIONS

The contribution of functional P-gp in blood-aqueous barrier was clearly demonstrated by analyzing the aqueous distribution of Rho-123 in the presence or absence of quinidine. These experiments only allow us to address one part of the blood-aqueous barrier, the capillary endothelium, and, to do so by using different substrates for P-gp, a sort of chemical analogy with the presumed blood-aqueous barrier across capillary endothelia. The alteration of P-gp function by pharmacotherapy or in pathological state should be considered in the ophthalmic medical treatment.

Endoxyloglucan transferase cDNA isolated from pea roots and its fluctuating expression in hydrotropically responding roots

We isolated an endoxyloglucan transferase cDNA (Ps-EXGT1) from the roots of an agravitropic pea mutant, ageotropum. The putative product of the cDNA was 34.1 kDa and consisted of 293 amino acid residues. The predicted amino acid sequence was 75.1-88.6% identical to those of EXGT genes in other plants. The Ps-EXGT1 cDNA was strongly expressed in elongating roots and stems but not in either mature stems or young leaves. In roots, the transcription level of Ps-EXGT1 was most abundant in the rapidly growing region. When root elongation was inhibited by a water stress, Ps-EXGT1 transcription was repressed. The roots curved hydrotropically due to differential growth of the cortical cells in the elongation zone when the root cap was exposed to a gradient of water potential; the length of the cells on the side of lower water potential was much longer than those on the side of higher water potential. The expression pattern of Ps-EXGT1 in the hydrotropically responding roots fluctuated between the side of the higher water potential and that of the lower water potential in the elongation zone. In other words, the accumulation of Ps-EXGT1 mRNA was much greater on the side of lower water potential than on that of higher potential just prior to the commencement of positive hydrotropism. When the roots started to curve slightly away from the side of higher water potential causing a rhythmic oscillatory movement [Takano et al. (1995) Planta 197: 410], there was more transcription of Ps-EXGT1 on the side of higher water potential. These results suggest that the transcription of Ps-EXGT1 is involved in cell growth and that this regulation of transcription plays a role in the differential growth of hydrotropically responding roots.

Wortmannin, an inhibitor of phosphatidylinositol kinases, blocks the MgATP-dependent recovery of Kir6.2/SUR2A channels

1. In order to investigate the mechanism underlying MgATP-dependent recovery of ATP-sensitive potassium (KATP) channels, we expressed Kir6.2/SUR2A (inwardly rectifying K+ channel subunit/sulfonylurea receptor) or C-terminal-truncated Kir6.2 (Kir6.2DeltaC26) in COS7 cells (Green monkey kidney cells), and carried out inside-out patch clamp experiments. 2. After patch excision in ATP-free internal solution, the activity of Kir6.2/SUR2A channels could be maximally recovered by the application of 5 mM MgATP. Subsequent application of 100 microM Ca2+ induced a rapid decay of Kir6.2/SUR2A activity to 11.6 +/- 1.1 % (mean +/- s.e.m.) of the control level (Ca2+-induced run-down; n = 64). 3. MgATP (5 mM) recovered 99.4 +/- 4.2 % (n = 13) of the Ca2+-induced run-down. Protein kinase inhibitors such as W-7, H-7, H-8 and genistein did not inhibit this reaction. However, wortmannin, an inhibitor of phosphatidylinositol 3- and 4-kinases, blocked the MgATP-dependent recovery in a concentration-dependent manner; the magnitudes of recovery were 35.7 +/- 7.2 % (10 microM) and 4.3 +/- 2.5 % (100 microM) of the Ca2+-induced run-down. 4. MgUDP (10 mM) reversed the Ca2+-induced run-down of Kir6.2/SUR2A channels by 60.4 +/- 7.6 % (n = 5). Wortmannin failed to modify this reaction. 5. Kir6.2DeltaC26 channels, which opened in the absence of SUR2A, were less sensitive to Ca2+; Kir6.2DeltaC26 channels were inactivated to 44.8 +/- 4.4 % (n = 14) by 100 microM Ca2+. MgATP recovered the Ca2+-induced run-down of Kir6.2DeltaC26 by 89.8 +/- 7. 7 % (n = 9), and 100 microM wortmannin inhibited this reaction (1.8 +/- 2 %, n = 7). 6. Application of 10 microM phosphatidylinositol-4, 5-bisphosphate (PI-4,5-P2) recovered the activity of Kir6.2/SUR2A channels after Ca2+-induced run-down (104.3 +/- 6.4 %, n = 10). Even after the MgATP-dependent recovery was blocked by 100 microM wortmannin, PI-4,5-P2 reactivated the channels (102.3 +/- 8.6 %, n = 5). Similar results were obtained with Kir6.2DeltaC26. 7. These results suggest that the entity of MgATP-dependent recovery may be membrane lipid phosphorylation rather than protein phosphorylation, and that synthesis of PI-4,5-P2 or phosphatidylinositol-3,4, 5-trisphosphate may upregulate Kir6.2 channels.

Thermostability reinforcement through a combination of thermostability-related mutations of N-carbamyl-D-amino acid amidohydrolase

For the improvement of N-carbamyl-D-amino acid amidohydrolase (DCase), which can be used for the industrial production of D-amino acids, the stability of DCase from Agrobacterium sp. KNK712 was improved through various combinations of thermostability-related mutations. The thermostable temperature (defined as the temperature on heat treatment for 10 min that caused a decrease in the DCase activity of 50%) of the enzyme which had three amino acids, H57Y, P203E, and V236A, replaced was increased by about 19 degrees C. The mutant DCase, designated as 455M, was purified and its enzymatic properties were studied. The enzyme had highly increased stability against not only temperature but also pH, the optimal temperature of the enzyme being about 75 degrees C. The substrate specificity of the enzyme for various N-carbamyl-D-amino acids was changed little in comparison with that of the native enzyme. Enzymochemical parameters were also measured.

Neurotoxic effects of phenytoin on postnatal mouse brain development following neonatal administration

Phenytoin (PHT) is a commonly used anticonvulsant drug. It has been reported that children exposed prenatally to PHT have brain malformations and psychomotor dysfunction. The neonatal development of the central nervous system (CNS) in mice corresponds to the last trimester in humans. To examine the neurotoxic effects of PHT on postnatal brain development, we administered PHT at doses of 10, 17.5, 25, or 35 mg/kg to newborn mice once a day during postnatal days (PD) 2-4. These dose levels result in plasma levels corresponding to the therapeutic ranges in humans. We measured the weight of total brain, cerebrum, cerebellum, and brain stem on PD 5 through 21, and examined early motor functions including head elevation, elevation of pelvis, pivoting, crawling, and righting reflex . Total brain weight, cerebral weight, and cerebellar weight in the group treated with 25 or 35 mg/kg were significantly reduced compared to controls from PD 5 to 21. Mice treated with PHT at 25 or 35 mg/kg showed decreased locomotor abilities and righting reflex on PD 5. In all phenytoin treatment groups, phenytoin levels in the brain were higher than those in the plasma on the third day of PHT treatment. We thus observed neurotoxic effects of PHT on postnatal brain development in mice. Our present data may provide useful implications for the management of PHT-induced developmental neurotoxicity and evaluation of psychomotor development in children exposed to PHT during the late fetal period.

Agravitropic mutant for the study of hydrotropism in seedling roots

Roots have been shown to respond to a moisture gradient by positive hydrotropism. Agravitropic mutant plants are useful for the study of the hydrotropism in roots because on Earth hydrotropism is obviously altered by the gravity response in the roots of normally gravitropic plants. The roots are able to sense water potential gradient as small as 0.5 MPa mm(-1). The root cap includes the sensing apparatus that causes a differential growth at the elongation region of roots. A gradient in apoplastic calcium and calcium influx through plasmamembrane in the root cap is somehow involved in the signal transduction mechanism in hydrotropism, which may cause a differential change in cell wall extensibility at the elongation region. We have isolated an endoxy loglucan transferase (EXGT) gene that is strongly expressed in pea roots and appears to be involved in the differential growth in hydrotropically responding roots. Thus, it is now possible to study hydrotropism in roots by comparing with or separate from gravitropism. These results also imply that microgravity conditions in space are useful for the study of hydrotropism and its interaction with gravitropism.

[The effect of midazolam on the memory during cesarean section and the modulation by flumazenil]

In 30 patients (ASA-1) for elective Cesarean section who had given informed consent, characteristics of amnesia induced by midazolam (M) and their modulation by flumazenil (F) were examined. Spinal anesthesia was performed with dibucaine. After the delivery, the baby was shown to the mother. Then 21 patients were given bolus intravenous injection of M until the patient got into sleep and the inhalation of nitrous oxide mixed with oxygen was started. At the end of surgery bolus injection of F 0.1 mg was cumulatively repeated until the patient awoke. Nine patients were given only nitrous oxide and oxygen inhalation after the delivery. The remembrance of the baby face and the doses of M and F were compared. In group given M, 14 patients recalled their baby's face whereas 7 did not. The average doses of M and F in patients with memory were 69 micrograms.kg-1 and 2.5 micrograms.kg-1, respectively, whereas the average dose of M and F in patients without memory were 94 micrograms.kg-1 and 4.2 micrograms.kg-1, respectively. In the patients without M injection, all could recall the face of the baby. These results suggest that M could produce retrograde amnesia, when combined with nitrous oxide inhalation, which is not reversed by F.

Characterization of biosynthetic enzymes for ectoine as a compatible solute in a moderately halophilic eubacterium, Halomonas elongata

1,4,5,6-Tetrahydro-2-methyl-4-pyrimidinecarboxylic acid (ectoine) is an excellent osmoprotectant. The biosynthetic pathway of ectoine from aspartic beta-semialdehyde (ASA), in Halomonas elongata, was elucidated by purification and characterization of each enzyme involved. 2,4-Diaminobutyrate (DABA) aminotransferase catalyzed reversively the first step of the pathway, conversion of ASA to DABA by transamination with L-glutamate. This enzyme required pyridoxal 5'-phosphate and potassium ions for its activity and stability. The gel filtration estimated an apparent molecular mass of 260 kDa, whereas molecular mass measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was 44 kDa. This enzyme exhibited an optimum pH of 8.6 and an optimum temperature of 25 degreesC and had Kms of 9.1 mM for L-glutamate and 4.5 mM for DL-ASA. DABA acetyltransferase catalyzed acetylation of DABA to gamma-N-acetyl-alpha,gamma-diaminobutyric acid (ADABA) with acetyl coenzyme A and exhibited an optimum pH of 8.2 and an optimum temperature of 20 degreesC in the presence of 0.4 M NaCl. The molecular mass was 45 kDa by gel filtration. Ectoine synthase catalyzed circularization of ADABA to ectoine and exhibited an optimum pH of 8.5 to 9.0 and an optimum temperature of 15 degreesC in the presence of 0.5 M NaCl. This enzyme had an apparent molecular mass of 19 kDa by SDS-PAGE and a Km of 8.4 mM in the presence of 0. 77 M NaCl. DABA acetyltransferase and ectoine synthase were stabilized in the presence of NaCl (>2 M) and DABA (100 mM) at temperatures below 30 degreesC.

Dose-dependent intestinal and hepatic first-pass metabolism of midazolam, a cytochrome P450 3A substrate with differently modulated enzyme activity in rats

The dose-dependent first-pass metabolism of midazolam, a cytochrome P450 (CYP) 3A substrate, was separately estimated in the intestine and liver after administration into a jejunal loop of rats with differently modulated enzyme activity. Modulation of CYP3A enzyme activity of Sprague-Dawley rats was performed by pretreating the rats with inducers such as dexamethasone or by co-administering ketoconazole (an inhibitor) with midazolam. Bioavailabilities of midazolam administered into the jejunal loop at a dose of 10 micromol were 12% in untreated (control) rats, and 2% in dexamethasone-pretreated rats. Co-administered ketoconazole (2 micromol) significantly increased the bioavailability to 53% and 7%, respectively, in these rats. The intestinal first-pass metabolism of midazolam administered into the jejunal loop at a dose of 50 nmol in untreated and dexamethasone-pretreated rats, estimated by the mesenteric blood-collecting method in-situ, was 25% and 49% of absorbed amount, respectively. The intestinal first-pass metabolism of midazolam was reduced when ketoconazole (0.5 micromol) was co-administered or when the dose of midazolam was increased to 0.5 micrommol in these rats. Assuming that the contribution of intestinal first-pass metabolism could be negligible when midazolam was administered at a much higher dose of 10 micromol, the estimated hepatic first-pass metabolism of midazolam at a dose of 10 micromol in untreated rats, dexamethasone-pretreated rats, untreated rats given ketoconazole, and dexamethasone-pretreated rats given ketoconazole was, respectively, 86, 97, 46, and 92% of the amounts absorbed. In conclusion, the dose-dependent intestinal first-pass metabolism and the hepatic first-pass metabolism of midazolam in rats with differently modulated CYP3A activities was quantitatively estimated by in-vivo and in-situ absorption studies.

Expression analysis of the autolysin gene (atl) of Staphylococcus aureus

The bifunctional autolysin gene (atl) of Staphylococcus aureus was transcribed into a 4.1-kb transcript. The transcription initiation site was located at an adenine residue 33-nt upstream from the putative atl start codon. Analysis using a promoter-reporter plasmid showed that promoter activity increased during the exponential growth phase. The Tn551 insertion site of the autolysis-deficient mutant S. aureus RUSAL2 was located in the putative catalytic region of the glucosaminidase domain.

Rice has two distinct classes of protein kinase genes related to SNF1 of Saccharomyces cerevisiae, which are differently regulated in early seed development

We have isolated five cDNA clones (osk1-5) for protein kinases from rice which are related to SNF1 protein kinase of Saccharomyces cerevisiae. Based on the sequence homology, these cDNAs can be classified into two groups, group 1 (osk1) and group 2 (osk2-5). The products of these genes were demonstrated to be functional SNF1-related protein kinases by in vitro and in vivo experiments. Recombinant proteins expressed from both groups of genes were fully active as protein kinases and could phosphorylate SAMS peptide, a substrate specific for the SNF1/AMPK family, as well as themselves (autophosphorylation). Moreover, expression of osk3 cDNA in yeast snf1 mutants restored SNF1 function. Northern blot analyses showed differential expression of these two gene groups; group 1 is expressed uniformly in growing tissues (young roots, young shoots, flowers, and immature seeds), whereas group 2 is strongly expressed in immature seeds. SNF1-related protein kinases have been reported from different plant species, such as rye, barley, Arabidopsis, tobacco, and potato, while the type of gene strongly expressed in immature seeds is known only in cereals such as rye, barley, and, from our findings, in rice. Expression levels of the group 2 genes were further analyzed in seeds during seed maturation. Expression is transiently increased in the early stages of seed maturation and then decreases. The expression peak precedes those of the sbe1 and waxy genes, which are involved in starch synthesis in rice. Taken together, these findings suggest that group 2 OSK genes play important roles in the early stages of endosperm development in rice seeds.

A long-term survivor case of malignant mesothelioma treated by recombinant tumor necrosis factor-SAM2 (TNF-alpha mutein) and 5-fluorouracil (5-FU): a new therapeutic approach based on host-tumor relationship

BACKGROUND

The prognosis of mesothelioma is very poor, and there is no established method to suppress tumor growth. Immunological approaches have recently been thought to be effective for mesothelioma and several studies using cytokines have been performed. We used a novel recombinant tumor necrosis factor-alpha (rTNF-alpha) we called rTNF-SAM2, in the treatment of a patient with this disease.

PATIENT AND METHOD

A 48-year old male patient with ascites was diagnosed with malignant mesothelioma by cytological examination. TNF-SAM2 in an amount of 264 to 576 micrograms (1 to 2.2 x 10(6) U) was injected via a catheter several times. Five hundred mg of 5 fluorouracil (5-FU) was also given via catheter once a week and 5-FU derivative was given orally every day.

RESULTS

No apparent tumor progression was observed for 6 years and 6 months and the patient led a normal life. During the therapy, the malignancy of tumor cells from the ascites changed from class V to class VI.

CONCLUSION

TNF based therapy may be promising treatment for the suppression of malignant mesothelioma.

The antiarrhythmic agent cibenzoline inhibits KATP channels by binding to Kir6.2

We reported previously that cibenzoline, an antiarrhythmic agent, inhibits the ATP-sensitive K+ (KATP) channels of pancreatic beta-cells through a binding site distinct from that for glibenclamide. In the present study, we have determined the locus of the action of cibenzoline on KATP channels reconstituted with mutant Kir6.2 and SUR1. We expressed a C-terminal truncated Kir6.2 (Kir6. 2DeltaC26) with and without SUR1 in COS7 cells. Both Kir6.2DeltaC26 and Kir6.2DeltaC26 + SUR1 formed functional KATP channels. Glibenclamide inhibited Kir6.2DeltaC26 + SUR1 channels but failed to inhibit Kir6.2DeltaC26. In contrast, cibenzoline inhibited equally Kir6.2DeltaC26 and Kir6.2DeltaC26 + SUR1 channels, in a dose-dependent manner, the half-maximal concentrations of channel inhibition being 22.2 +/- 6.1 and 30.9 +/- 9.4 microM, respectively. Furthermore, we determined also that [3H]cibenzoline bound to Kir6. 2DeltaC26. These findings confirm that cibenzoline inhibits KATP channels by a novel inhibitory mechanism in which cibenzoline directly affects the pore-forming Kir6.2 subunit rather than the SUR1 subunit.

Cytoplasmic terminus domains of Kir6.x confer different nucleotide-dependent gating on the ATP-sensitive K+ channel

1. In order to investigate the structural basis for the nucleotide-dependent gating of ATP-sensitive K+ channels (KATP), Kir6.1 (uKATP-1), Kir6.2 (BIR1) and chimeric channels were co-expressed with a common subtype of sulphonylurea receptor, SUR1, in COS7 cells. Representing the amino terminal domain-transmembrane domain-carboxyl-terminal domain of Kir6.1 as 1-1-1 and of Kir6.2 as 2-2-2, chimeric Kir6.x channels were constructed by swapping the amino and/or carboxyl terminal domains between Kir6.1 and Kir6.2 to give the chimeric x-1-x channels 1-1-2, 2-1-1 and 2-1-2, and the chimeric x-2-x channels 2-2-1, 1-2-2 and 1-2-1. 2. Inside-out patch clamp experiments revealed that both wild-type Kir6.1 and Kir6.2 formed inwardly rectifying K+ channels. Single-channel conductances were 36.3 and 66.1 pS, respectively. Chimeric x-1-x channels, whose transmembrane domain was that of Kir6.1, showed similar ion-pore properties to wild-type Kir6.1. Likewise, chimeric x-2-x channels had similar ion-pore properties to wild-type Kir6.2. 3. Wild-type Kir6.1 and Kir6.2 possessed distinct gating properties towards intracellular nucleotides. The activity of Kir6.1 was entirely dependent on Mg2+ and nucleotide diphosphates (NDPs) such as UDP. In contrast, Kir6.2 was activated upon excision of patch membrane. When Kir6.2 underwent rundown, UDP reactivated the channel. 4. In order to eliminate UDP dependence from Kir6.1, it was necessary to replace both N- and C-termini; chimera 2-1-2 opened in UDP-free conditions. With Kir6.2, substitution of the N-terminus with that of Kir6.1 conferred UDP dependence on chimeras 1-2-2 and 1-2-1. Chimera 2-2-1 opened in UDP-free conditions, but UDP potentiated the channel activity by > 20-fold. 5. The kinetics of UDP-dependent activation were significantly different between Kir6.1 and Kir6.2. Kir6.1 maximally activated by UDP was sensitive to intracellular ATP, although its ATP sensitivity was significantly lower than that of Kir6.2 measured in identical conditions. The kinetics of UDP-dependent activation and ATP sensitivity could be transferred between Kir6.1 and Kir6.2 only when both N- and C-termini were replaced. We therefore concluded that nucleotide-dependent gating was regulated by the N- and C-terminal domains irrespective of the transmembrane domains.

Interaction with P-glycoprotein and transport of erythromycin, midazolam and ketoconazole in Caco-2 cells

The effect of cytochrome P-450 3A (CYP3A) substrates (erythromycin, midazolam) and an inhibitor (ketoconazole) on P-glycoprotein-mediated transport was studied in Caco-2, the human colon adenocarcinoma cell line expressing various functions of differentiated intestinal epithelial cells. The involvement of P-glycoprotein in the transport of these drugs was also examined. The basal-to-apical transport of rhodamine 123, a P-glycoprotein substrate, was inhibited by erythromycin, midazolam and ketoconazole, as well as by P-glycoprotein inhibitors such as verapamil. The apical-to-basal transport of rhodamine 123 was increased by these drugs. The transepithelial transport of erythromycin and midazolam, but not of ketoconazole, was much greater from the basal to apical side than from the apical to basal side. The inhibitory effect of verapamil was observed on the basal to apical transport of erythromycin, but not on midazolam and ketoconazole transport. In conclusion, erythromycin, midazolam and ketoconazole could interact with P-glycoprotein-mediated transport, and P-glycoprotein could be, at least in part, involved in the transport of erythromycin, but not of midazolam and ketoconazole, in the intestinal epithelia.

Immobilization of N-carbamyl-D-amino acid amidohydrolase

N-Carbamyl-D-amino acid amidohydrolase (DCase), produced with recombinant Escherichia coli cells using a cloned gene from Agrobacterium sp. strain KNK712, has been immobilized for use in the production of D-amino acids. The porous polymers, Duolite A-568 and Chitopearl 3003, were much better than other resins for the activity and stability of the adsorbed enzyme. The activity of DCase expressed on Duolite A-568 and Chitopearl 3003 amounted to 96 units/g-wet-resin and 91 units/g-wet-resin, respectively. DCase immobilized on Duolite A-568 was found to be most stable at about pH 7, and it was further stabilized by reductants such as dithiothreitol, L-cysteine, cysteamine, and sodium hydrosulfite. The stability during the repeated batch reactions was greatly improved when dithiothreitol was in the reaction mixture, and the higher crosslinking degree with glutaraldehyde also stabilized the immobilized enzyme. After 14 times repeated reactions, the remaining activity of the immobilized enzyme cross-linked with 0.1% and 0.2% of glutaraldehyde, and 0.2% of glutaraldehyde with dithiothreitol in the reaction mixture was 12%, 18%, and 63%, respectively. DCase produced with Pseudomonas sp. strain KNK003A and Pseudomonas sp. strain KNK505, which are thermotolerant soil bacteria, and that with Agrobacterium sp. strain KNK712 were also immobilized on Duolite A-568. The stability of the enzymes of thermotolerant bacteria during reactions was superior to that of Agrobacterium sp. strain KNK712, though the activity was lower than that of strain KNK712.

[Effect of CDDP/5'-DFUR combination chemotherapy for advanced or recurrent gastric cancer]

CDDP/5'-DFUR combination chemotherapy was performed on 17 patients with non-resected and recurrent gastric cancer (clinical stage were IVb in all patients). They were treated with 1,400 mg/m2 of 5'-DFUR on days 1-4 orally following by withdrawal 10 days, every 2 weeks repeatedly and 80 mg/m2 of CDDP (c. i. v., on day 5, every 4 weeks). This chemotherapy was performed for at least 2 courses on all patients. Eight of 17 patients achieved a partial response and the overall response rate was 47.1% (differentiated type 57.1%, undifferentiated type 45.5%). Response rates of each lesion were as follows: primary foci 42.9%, abdominal lymph nodes 57.1%, hepatic metastasis 60.0% and ascites 33.3%, respectively. Improvement of performance status was seen in 12 of 17 patients (70.6%). The overall median survival time was 227 days. The median outpatient period was 113 days. There was no high-grade toxicity over grade 2. Therapeutic toxicity of grade 2 was manifested as renal dysfunction (23.5%), nausea/vomiting (17.6%), leukopenia (5.9%) and anemia (5.9%). We evaluated the therapeutic effect by visual examination after completion of the second course. However, poor effect and high incidence of renal dysfunction were found in patients treated with this therapy over four times. Therefore, the maximum effect seemed to be revealed after completion of the fourth course. From the present study, CDDP/5'-DFUR combination chemotherapy seems to be effective for patients with high-grade advanced gastric cancer and improved their quality of life.

Renal excretion of rhodamine 123, a P-glycoprotein substrate, in rats with glycerol-induced acute renal failure

To clarify renal handling of rhodamine 123, a substrate for P-glycoprotein, in normal and diseased states, in-vivo clearance studies were performed with normal rats and rats with glycerol-induced acute renal failure. For normal rats the excretion ratio of unbound rhodamine 123-to-inulin was 3.25, indicating the presence of the renal tubular secretion of rhodamine 123. Co-administration of cyclosporin, a P-glycoprotein inhibitor, significantly reduced tubular secretion of rhodamine 123. Administration of glycerol induced both an increase in blood urea nitrogen and a reduction in the glomerular filtration rate, confirming the induction of acute renal failure. Total plasma, renal, and tubular secretory clearances of rhodamine 123 were significantly lower for rats with acute renal failure than for control rats. There was no difference between the ATP content of the renal cortex in control rats and those with acute renal failure. In addition to the decrease in renal clearance, a decrease in the biliary clearance of rhodamine 123 was also observed in rats with acute renal failure. These results imply that rhodamine 123 is secreted via P-glycoprotein in renal tubules and that the renal secretory clearance of rhodamine 123 was reduced after acute renal failure, probably because of impairment of P-glycoprotein.

Kininogen expression by rat vascular smooth muscle cells: stimulation by lipopolysaccharide and angiotensin II

To identify the presence of a local kallikrein-kinin system in vascular wall, we have studied whether rat vascular smooth muscle cells (VSMC) express kininogen in vitro and in vivo. Western blots using anti-T-kininogen antibody revealed the presence of T-kininogen in conditioned medium of cultured VSMC. T-Kininogen secretion by VSMC was markedly enhanced by the addition of lipopolysaccharide (LPS), angiotensin II (AII) and phorbol 12-myristate 13-acetate (PMA) to the culture. Experiments using specific inhibitors for protein kinases and on the PMA-induced down-regulation of protein kinase C suggested that a protein kinase C-dependent or unidentified pathway is involved in AII or LPS action, respectively. The intravenous injection of LPS (0.5 mg/kg) resulted in an increase in T-kininogen mRNA levels in the vascular smooth muscle of rat aorta, peaking at 16 h. Polyacrylamide gel electrophoresis of cDNA products generated by reverse transcription-polymerase chain reaction (RT-PCR) from aortic mRNA using primers specific for either T- or low-molecular-weight kininogen revealed that rat vascular smooth muscle expressed T-kininogen gene but not low-molecular-weight kininogen gene, and that LPS exclusively stimulated T-kininogen expression. The mRNA for high-molecular-weight kininogen was undetectable in either aortic smooth muscle or cultured VSMC by means of RT-PCR analysis. RT-PCR using specific primers for rat tissue kallikrein genes showed that aortic smooth muscle expressed KLK1 (true kallikrein) mRNA, but not KLK10 (T-kininogenase) mRNA. These results demonstrated that rat VSMC are a source of T-kininogen but not of low-molecular-weight- or high-molecular-weight kininogen, in contrast to the expression of true kallikrein but not of T-kininogenase by these cells.

Prostaglandin E2 protects against liver injury after Escherichia coli infection but hampers the resolution of the infection in mice

cAMP-increasing agents such as prostaglandin E2 (PGE2) are known to protect against LPS-induced liver injury by downregulating the production of inflammatory cytokines such as TNF-alpha. However, the effects of such reagents on host defense against bacterial infection remain unknown. We show here that in vivo administration of PGE2 significantly protected mice against liver injury after Escherichia coli infection but hampered the resolution of the infection. PGE2 significantly suppressed circulating TNF-alpha and IL-12 levels but increased the IL-10 production after E. coli challenge. PGE2 inhibited the emergence of gammadelta T cells in the peritoneal cavity, which are important for host defense against E. coli, and deteriorated bacterial exclusion in the peritoneal cavity after E. coli challenge. These results suggested that PGE2 affects host defense mechanisms against E. coli infection through modulation of cytokine production and gammadelta T cell accumulation.

Clinical and neuroimaging features of Chiari type I malformations with and without associated syringomyelia

The clinical and neuroimaging characteristics of 22 consecutive patients with Chiari type I malformations were evaluated to investigate the pathogenesis of syrinx formation. All patients underwent magnetic resonance imaging and x-ray tomography before surgery. The electric manometric Queckenstedt test was performed on 16 patients pre- and postoperatively. Syringomyelia was present in 17 patients and absent in five patients. All patients without syringomyelia suffered from foramen magnum compression syndrome, with a wider basal angle, more acute clivo-axial angle, shorter clivus, and more prominent tonsillar ectopia than patients with syringomyelia. Low brain stem position, basilar impression, and beaking of the cervicomedullary junction were also more prominent in patients without syringomyelia. Marked to complete block with the neck in flexed position by Queckenstedt test was present in all patients except one. Patients with Chiari malformation not associated with syringomyelia have more pronounced compression of the brain stem at the foramen magnum. Therefore, despite a block of the cerebrospinal fluid pathway at the foramen magnum, syrinx formation may be prevented by severe compression.

Increase in thermostability of N-carbamyl-D-amino acid amidohydrolase on amino acid substitutions

To improve the production of D-amino acids using an immobilized N-carbamyl-D-amino acid amidohydrolase, the enzyme gene of Agrobacterium sp. KNK712 was mutagenized randomly to increase its thermostability. The gene was inserted into M13mp19, mutagenized with hydroxylamine, ligated into pUC19 after restriction endonuclease digestion, and then used to transform Escherichia coli. The resultant transformants were screened by a newly developed colorimetric enzyme assay method, and the candidate colonies corresponding to red spots were separated from the master plates. Using cell-free extracts of these clones, the properties of the enzymes produced were investigated, it being proved that these enzymes had almost the same activity and improved thermostability by about 5 degrees C compared with those of the native enzyme. As found on enzyme gene analysis of these mutants, the 57th amino acid, histidine, of the enzyme was changed to tyrosine, or the 203rd amino acid, proline, to leucine or serine.

Relationship between an increase in thermostability and amino acid substitutions in N-carbamyl-D-amino acid amidohydrolase

For the production of D-amino acids using stable N-carbamyl-D-amino acid amidohydrolase (DCase) in an immobilized form, the DCase gene of Agrobacterium sp. KNK712 was mutagenized to increase its enzymatic thermostability. In a search for thermostability-related amino acid sites besides the two known sites of DCase, i.e., the 57th and 203rd amino acids, the new mutant enzyme found, in which the 236th amino acid, valine, had been changed to alanine, showed a 10 degrees C increase in thermostability. These known three thermostability-related amino acids were changed to other amino acids by the PCR technique, and it was proved that the thermostability of the DCase increased when the 57th amino acid of DCase, histidine, was changed to leucine, the 203rd amino acid, proline, to asparagine, glutamate, alanine, isoleucine, histidine, or threonine, and the 236th amino acid, valine, to threonine or serine, in addition to the known mutations.

Preservation of metastatic ability of colorectal tumor cells stratified by inducibility of endogenous tumor necrosis factor after orthotopic transplantation in nude mice

BACKGROUND

Inducibility of endogenous tumor necrosis factor (TNF) by colorectal tumor cells can be regarded as a novel prognostic factor in terms of distant metastasis or local recurrence following curative operation, especially at Duke's stage C. In this study, the metastatic ability of human colorectal tumor cells stratified by inducibility of endogenous TNF was analyzed by orthotopic transplantation in nude mouse.

METHODS

Fifty three cases of freshly resected colorectal tumor specimens cut into about 50mg pieces were inoculated into the cecum wall of nude mice. Two to nine months after transplantation, tumor growth on this wall and metastases to the peritoneal wall as well as to the liver were assessed.

RESULTS

Of forty one evaluable cases, successful transplantation was observed in twenty nine (70%), and metastases to the peritoneal wall or to the liver was found in thirteen (32%), or eight cases (20%), respectively. In the twenty nine cases with local tumor growth, incidence of the liver metastases in nude mice when tumor specimens from patients with liver metastases (4/8) were used was significantly higher than that from patients without liver metastases (4/21) (P = 0.096). Inducibility of endogenous TNF was separately analyzed in fourteen of the evaluable twenty nine cases. Seven cases belonged to the high group and seven to the low group in terms of the amount of endogenous TNF secreted by tumor cells. Incidence of metastases in mice was 1/7 in the high group and 6/7 in the low group, and there was a statistically significant difference between liver metastases in mice and inducibility of endogenous TNF by colorectal tumor cells (p = 0.0057).

CONCLUSION

From these results, it is strongly suggested that inducibility of endogenous TNF by colorectal tumor cells can affect a patient's prognosis since it regulates metastatic ability to the liver.

Veins of the lumbar spinal ganglia in human adults and fetuses

To obtain a fundamental knowledge of the morphological relationship between nerve root symptoms and circulatory disorders, the distribution pattern of the veins in the lumbar spinal ganglia from the first to fifth vertebrae was investigated in 5 adult human cadavers (mean age 69.6 years) and 5 human fetuses (mean age 6.6 months). The following results were obtained: 1) In the adults the veins perforating from the outer surface of the fifth lumbar spinal ganglion were smaller in number than those perforating from the first to fourth ganglia. In contrast, in the fetuses the number of such veins was increased in the lower lumbar spinal ganglia. In each of the ganglia, the number of veins emerging through the dorsal side was much higher than the number perforating from the outer surface of the ventral sides. The veins perforating through the outer surface of the ganglion formed weak venous networks (periganglionic venous plexus) surrounding the dorsal ramus of the spinal nerve. 2) The veins communicating with the tributaries from the periganglionic venous plexus were classified into three types. Type 1 veins flowed into the intervertebral veins (the frequency ranged from 9.2 to 18.2 in the adults and from 22.4 to 37.0 in the fetuses). Type 2 veins coursed in the spinal cord along the dorsal root fibers and penetrated the dura mater on the way (the frequency ranged from 0.4 to 4.8 in the adults and from 1.2 to 2.2 in the fetuses). Type 3 veins opened directly into the internal vertebral plexus (the frequency ranged from 0.4 to 1.8 in the adults and from 0 to 0.4 in the fetuses). Type 1 veins were the most frequent among the three types of veins in both adults and fetuses. Few type 3 veins were observed in either group. 3) In the first and second lumbar vertebrae in the adults, three-quarters of each spinal ganglion was situated in the vertebral canal. In the lower lumbar region (L3-L5), three quarters of each spinal ganglion lay on the outside of the vertebral canal. In the fetuses, approximately one half to three-quarters of each lumbar spinal ganglion was located in the vertebral canal.

Distinct characteristics of transcellular transport between nicotine and tetraethylammonium in LLC-PK1 cells

To clarify the mechanisms of the renal tubular secretion of nicotine, we studied transport of nicotine in the kidney epithelial cell line LLC-PK1. The transcellular transport of nicotine from the basolateral side to the apical side of the LLC-PK1 monolayers grown on membrane filters was much greater than that of tetraethylammonium. The basolateral-to-apical transport of nicotine was stimulated by lowering the pH of the apical side, accompanied by a decrease in the accumulation of nicotine. The accumulation of nicotine from the basolateral side was inhibited by unlabeled nicotine, cotinine, tetraethylammonium, cimetidine and quinidine. The uptake of nicotine across the apical membrane was inhibited by unlabeled nicotine and quinidine but not by tetraethylammonium or cimetidine. Pretreatment with p-chloromercuribenzene sulfonate caused a decrease in the transcellular transport of tetraethylammonium but not of nicotine. These results suggest that nicotine undergoes vectorial transport from basolateral side to the apical side of LLC-PK1 monolayers in a H+ gradient-dependent manner, corresponding to the secretion in the renal tubules. Nicotine transport in LLC-PK1 cells could be mediated by a transport system that is distinct from the transport system for tetraethylammonium.

[Exercises on a bicycle ergometer in a family of diabetes mellitus associated with a mutation of mitochondrial DNA]

The serum pyruvate and lactate levels were studied after exercise on a bicycle ergometer in a family of diabetes mellitus (DM) associated with a mutation at nucleotide 3243 in the mitochondrial gene. A 56-year-old Japanese woman with the mutation at a percentage of 5% in the blood had insulin-dependent DM and sensory hearing loss without muscle symptoms. Her serum lactate and pyruvate levels increased markedly during and after exercise on a bicycle ergometer. Two of her sons were found to have the same mutation at a percentage of 17% and 18%, respectively. Her 26-year-old son was found to have borderline DM after oral glucose loading, although he showed no abnormalities of the metabolism of pyruvate and lactate. Her 31-year-old son showed no abnormalities after oral glucose loading and after exercise on a bicycle ergometer. Although the same mutation causes more severe MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes), little is known about whether these diabetic patients are subclinically involved with myopathy. The noninvasive ergometer exercise with determination of serum pyruvate and lactate may be useful in evaluating the severity of myopathy in these patients.

Protective roles of gamma delta T cells and interleukin-15 in Escherichia coli infection in mice

The number of gamma delta T cells in the peritoneal cavity was increased after an intraperitoneal (i.p.) infection with Escherichia coli in lipopolysaccharide (LPS)-responsive C3H/HeN mice but not in LPS-hyporesponsive C3H/HeJ mice. The gamma delta T cells preferentially expressed invariant Vgamma6 and Vdelta1 chains and proliferated to produce a large amount of gamma interferon in the presence of LPS. Mice depleted of gamma delta T cells by T-cell receptor delta gene mutation showed impaired resistance against E. coli as assessed by bacterial growth. Macrophages from C3H/HeN mice infected with E. coli expressed higher levels of interleukin-15 (IL-15) mRNA than those from the infected C3H/HeJ mice. Administration of anti-IL-15 monoclonal antibody inhibited, albeit partially, the appearance of gamma delta T cells in C3H/HeN mice after E. coli infection and diminished the host defense against the infection. These results suggest that LPS-stimulated gamma delta T cells play an important role in the host defense against E. coli infection and that IL-15 may be partly involved in the protection via an increase in the gamma delta T cells.

Expression of low-molecular-weight kininogen in mouse vascular smooth muscle cells

To determine the existence of the kallikrein-kinin system in vascular wall, the expression of low-molecular-weight (LMW) kininogen, a precursor protein of kinins, was studied in mouse aortic smooth muscle in vivo or in cultured vascular smooth muscle cells (VSMC) derived from mouse aorta in vitro. Although LMW-kininogen mRNA was undetectable in aortic smooth muscle of untreated mice using either Northern blotting or reverse transcription-polymerase chain reactions (RT-PCR) followed by Southern blotting, administration of lipopolysaccharide (LPS; 1 mg/kg, i.v.) induced the expression of LMW-kininogen mRNA at levels detectable by RT-PCR within 12 h. Cultured VSMC not only expressed LMW-kininogen mRNA at levels easily detectable by RT-PCR, but also secreted LMW-kininogen-like protein that was immunoreactive to anti-mouse LMW-kininogen antibody. These results demonstrate that VSMC are a source of LMW-kininogen in the mouse, and suggest the presence of a local kallikrein-kinin system in vascular tissue. LPS-induced up-regulation of LMW-kininogen expression suggests a role for vascular LMW-kininogen in tissue trauma or inflammation.

Dibutyryl cyclic adenosine monophosphate protects mice against tumor necrosis factor-alpha-induced hepatocyte apoptosis accompanied by increased heat shock protein 70 expression

Liver injury accompanied by apoptosis of hepatocytes was provoked in mice by an intravenous injection of recombinant tumor necrosis factor-alpha (rTNF-alpha) (1.0 microg/kg) together with an intraperitoneal injection of D-galactosamine (D-gal) (500 mg/kg). Injection of various doses of dibutyryl cAMP (DBcAMP) protected mice from TNF-alpha/D-gal-induced liver injury as assessed by serum alanine aminotransferase (ALT) levels, histological examination and DNA fragmentation. DBcAMP significantly enhanced the Hsp70 expression in the hepatocytes of D-gal/TNF-alpha-injected mice in close correlation with suppression of liver injury. DBcAMP induced Hsp70 expression in the hepatocyte in vitro. These results suggest that increase in Hsp70 expression by DBcAMP is involved in protective mechanisms by DBcAMP against TNF-alpha-induced liver injury in D-gal-sensitized mice.

In-vivo calibration of microdialysis probe by use of endogenous glucose as an internal recovery marker: measurement of skin distribution of tranilast in rats

To estimate the absolute concentration of substrates surrounding a microdialysis probe in-vivo, we developed a simple calibration method using endogenous glucose as an internal recovery marker and determined the skin distribution of tranilast (N-(3,4-dimethoxy-cinnamoyl)anthranic acid), an anti-allergic agent, in rats. This calibration method was based on the assumption that the concentration of glucose in the extracellular fluid of skin tissues is the same as that in plasma and that the in-vivo recovery ratio of glucose to tranilast by microdialysis is the same as that estimated in-vitro. Based on these assumptions, the dialysate concentrations of tranilast and glucose recovered from cutaneous microdialysis, glucose concentration in plasma, and in-vitro recovery ratio of tranilast to glucose by microdialysis were determined for the estimation of absolute unbound concentration of tranilast in the extracellular fluid of skin tissues. In an in-vitro study employing plasma containing tranilast, the unbound concentration of tranilast in plasma estimated from the dialysate concentration was just comparable with that determined by ultrafiltration methods. Also in an in-vivo study under steady-state plasma concentration of tranilast in rats, the estimated concentration of tranilast in the skin extracellular fluid was the same level as the unbound concentration of tranilast in plasma. Using the present calibration method, the skin distribution of tranilast administered into the intestinal loop or transdermally was continuously monitored in a quantitative manner.

Screening, characterization, and cloning of the gene for N-carbamyl-D-amino acid amidohydrolase from thermotolerant soil bacteria

For the production of D-amino acids, thermotolerant bacteria producing N-carbamyl-D-amino acid amidohydrolase were isolated from soil by enrichment culture at 45 degrees C with N-carbamyl-D-amino acids as the sole nitrogen source. The enzyme activities and substrate specificities of these strains were examined by the resting cells reaction. One of the enzymes, produced by Pseudomonas sp. strain KNK003A, was purified and characterized, and the amino acids of its N-terminal region were sequenced. A DNA fragment containing the gene for a thermostable N-carbamyl-D-amino acid amidohydrolase was then cloned into Escherichia coli. The gene encoded a peptide of 312 amino acids, with a calculated molecular weight of 35,000. The similarity of the deduced amino acid sequences of this enzyme and a related enzyme from a mesophile, Agrobacterium sp. strain KNK712, was 60%. A database was searched for similar sequences.

Ambient but not incremental oxidant generation effects intercellular adhesion molecule 1 induction by tumour necrosis factor alpha in endothelium

Proinflammatory cytokines upregulate endothelial adhesion molecule expression, thereby initiating the microvascular inflammatory response. We re-evaluated the reported role of reactive oxygen metabolites (ROMs) in signalling upregulation of intercellular adhesion molecule 1 (ICAM-1) on endothelial cells by tumour necrosis factor alpha (TNF-alpha) in vitro. TNF-alpha upregulation of endothelial-cell ICAM-1 expression was inhibited by the cell-permeable antioxidants, or by the adenovirus-mediated intracellular overexpression of Cu,Zn-superoxide dismutase, but not by the exogenous (extracellular) administration of the cell-impermeable antioxidants, superoxide dismutase and/or catalase. This ICAM-1 upregulation was also inhibited by inhibitors of NADH dehydrogenase, cytochrome bc1 complex and NADPH oxidase. However, a measurable increase in net cellular ROM generation in response to TNF-alpha was not seen using four disparate sensitive ROM assays. Moreover, the stimulation of exogenous or endogenous ROM generation did not upregulate ICAM-1, nor enhance ICAM-1 upregulation by TNF-alpha. These findings suggest that an ambient background flux of ROMs, generated intracellularly, but not their net incremental generation, is necessary for TNF-alpha to induce ICAM-1 expression in endothelium in vitro.

Efflux of intracellular alpha-ketoglutarate via p-aminohippurate/dicarboxylate exchange in OK kidney epithelial cells

The involvement of intracellular alpha-ketoglutarate (alpha-KG) in p-aminohippurate (PAH) transport was investigated in OK kidney epithelial cells. Efflux of intracellular alpha-KG from the OK cells to the basolateral side was increased by applying PAH to the basolateral side of the cells. In contrast, the intracellular alpha-KG concentration was not influenced by the addition of PAH. The alpha-KG efflux across the basolateral membrane induced by PAH was higher than that across the apical membrane. Probenecid inhibited the PAH-dependent alpha-KG efflux. The alpha-KG efflux to the basolateral side was saturable with increasing concentration of PAH in the basolateral medium. Antimycin A, a metabolic inhibitor, inhibited [14C]PAH uptake across the basolateral membrane of OK cells in a dose-dependent manner. In addition, both the alpha-KG efflux induced by PAH and the intracellular alpha-KG concentration were decreased by antimycin A dose-dependently. These results directly show that alpha-KG generated by intracellular metabolism is effluxed via PAH/dicarboxylate exchange in the basolateral membrane of OK cells.

Isolation of Agrobacterium sp. strain KNK712 that produces N-carbamyl-D-amino acid amidohydrolase, cloning of the gene for this enzyme, and properties of the enzyme

Agrobacterium sp. strain KNK712, which produced N-carbamyl-D-amino acid amidohydrolase (DCase) was isolated from soil. The bacterium had D-specific hydantoinase activity also. Both enzymes are suitable for use in the production of D-amino acids. The DCase gene from Agrobacterium sp. strain KNK712 was cloned into Escherichia coli. The cloned DNA fragment contained one open reading frame, predicted to encode a peptide of 304 amino acids, with a calculated molecular weight of 34,285. The DCase gene was overexpressed under the control of the lac promoter, and DCase accounted for 50% of the soluble protein in the cells. The enzyme was purified and some properties were investigated. Both the optimum pH and the pH that gave greatest stability were about pH 7.0. The optimum temperature was 65 degrees C, and the enzyme was stable at 55 degrees C. The enzyme had strict specificity toward N-carbamyl-D-amino acids, and was inhibited by thiol reagents, Cu2+, Hg2+, Ag+, and ammonia.

Hepatic clearance of ONO-5046, a novel neutrophil elastase inhibitor, in rats and in the rat perfused liver

The hepatic clearance of ONO-5046 (N-[2-[4-(2,2-dimethylpropionyloxy)phenylsulphonylamino]benz oyl]aminoacetic acid), a low-molecular-weight neutrophil elastase inhibitor, has been investigated in rats and in the rat perfused liver. This ester was easily hydrolysed to its inactive metabolite EI-601 (N-[2-[(4-hydroxyphenyl)sulphonylamino]benzoyl]aminoacetic acid) in liver homogenate and in erythrocytes suspension in-vitro. On the other hand, it was stable in biological media such as plasma and whole blood, which contain plasma proteins. Scatchard plot analysis of ONO-5046 binding to bovine serum albumin (BSA) in-vitro indicated that the association constant (K) and number of binding sites (n) were 6.91 x 10(4) (M(-1)) and 4.33, respectively. Thus, ONO-5046 (100 microM) would bind to plasma proteins to an extent >99% at physiological plasma-protein concentrations. The total plasma clearance of ONO-5046 in rats was constant (approximately 9 mL min(-1) kg(-1)) under different steady-state plasma concentrations (5-50 microM) a value equivalent to the hepatic clearance. In the rat perfused liver, the hepatic extraction ratio of ONO-5046 was significantly reduced by adding BSA to the dosing solution. Thus, the relatively low hepatic clearance of ONO-5046, which has an ester linkage in its structure and is naturally susceptible to enzymatic hydrolysis, was found to be because of the extremely high protein-binding of the compound.

Pharmacokinetics and pharmacodynamics of acetazolamide in patients with transient intraocular pressure elevation

OBJECTIVE

To characterize the pharmacokinetics and pharmacodynamics of acetazolamide in patients with transient intraocular pressure (IOP) elevation and to provide individual patients with the optimal dosage regimen for this drug.

METHODS

We studied 17 patients with transient IOP elevation, who were given 62.5-500 mg acetazolamide orally as single or repetitive doses. Plasma acetazolamide concentration and IOP were measured at approximately 1, 3, 5, and 9 h after the last acetazolamide administration. Pharmacokinetics and pharmacodynamics were analyzed by nonlinear mixed-effect modeling using the program NONMEM.

RESULTS

The plasma concentration profile of acetazolamide was characterized by a one-compartment model with first-order absorption. The apparent oral clearance was related to the creatine clearance (CCR) which was estimated by the Cockcroft and Gault equation, as follows: 0.0468 x CCR1 x h(-1). The estimated apparent oral volume of distribution, first-order absorption rate constant, and absorption lag time were 0.231 l x kg(-1), 0.821 x h(-1), and 0.497 h, respectively. IOP after oral acetazolamide administration was characterized by an Emax model. The maximal effect in lowering the IOP (Emax) was 7.2 mmHg, and the concentration corresponding to 50% of the maximal effect (EC50) was 1.64 microg x ml(-1). As 70% of Emax was achieved at a plasma concentration of 4 microg x ml(-1), this concentration was considered satisfactory for lowering IOP. The recommended dosage was calculated so that the minimum plasma concentration at steady state exceeded this target concentration; 250 mg t.i.d., 125 mg t.i.d., 125 mg b.i.d., and 125 mg once daily for the patients with CCR values of 70, 50, 30, and 10 ml min(-1), respectively.

CONCLUSION

Measuring plasma concentrations of acetazolamide and subsequent pharmacokinetic and pharmacodynamic analyses are useful for estimating its concentration-dependent effectiveness in lowering the IOP in individual patients. The dosage regimen presented in this study is expected to improve the benefits of acetazolamide pharmacotherapy in most elderly patients with transient rises in IOP following intraocular surgery.

The inhibitory effect of propranolol on ATP-sensitive potassium channels in neonatal rat heart

1. Whole cell and single channel recordings of ATP-sensitive K+ current (I(K,ATP)) were carried out in ventricular myocytes isolated from neonatal rat hearts. 2. (+/-)-Propranolol, a commonly used beta-blocker, inhibited the whole cell I(K,ATP) in a concentration-dependent manner with a half-maximal concentration (IC50) of 6.7 +/- 1.4 microM, whereas it blocked the inward rectifier K+ current (I(K,I)) only at much higher concentrations (IC50 = 102.4 +/- 20.2 microM). The inhibition was time- and voltage-independent. 3. In the outside-out patch configuration, (+/-)-propranolol inhibited I(K,ATP) (IC50 = 9.8 +/- 2.9 microM) by decreasing the open probability of the channel without inducing additional noise in the open-channel current or a decrease of single channel conductance. The single channel current of I(K,I) was also blocked by (+/-)-propranolol in the same way as I(K,ATP). 4. (+)-Propranolol, an optic isomer having no beta-blocking effect, inhibited I(K,ATP) (IC50 = 5.8 +/- 1.0 microM), whilst atenolol, a selective beta1-blocker had no effect. Neither GDPbetaS (1 mM) nor GTPgammaS (200 microM) included in the pipette solution modulated the inhibitory effect of (+/-)-propranolol. 5. We concluded that the inhibitory effect of (+/-)-propranolol was not via the beta-adrenergic signal transduction pathway, but by direct inhibition of I(K,ATP) channels.

Clinical features of ovarian cancer in Japanese women with germ-line mutations of BRCA1

We analyzed the clinical features of 25 ovarian cancer patients who were associated with germ-line mutations of BRCA1 from four site-specific ovarian cancer families and seven breast-ovarian cancer families in Japan. The average age at diagnosis was 51.1 years (range, 38-77 years). Histological examination revealed 24 serous cyst adenocarcinomas in 25 patients. In 23 patients with clear clinical records, 3 patients had stage I disease, 17 had stage III disease, and 3 had stage IV disease. Thirteen patients with stage III disease who were treated with cisplatin-containing chemotherapy following tumor reduction surgery showed more favorable outcomes in both the survival rate and disease-free intervals, compared with age- and treatment course-matched controls (5-year survival rate, 0.786 versus 0.303; median disease-free interval, 91.43 versus 40.92 months; P < 0.05 for both, by logarithmic rank test). Our statistical model for the inheritance of susceptibility to ovarian cancer was derived from the analysis of 26 patients and 19 healthy carriers of 12 families. The expected lifetime risk of ovarian cancer is about 80% for women with mutations of BRCA1. These results suggest that the clinical outcome of ovarian cancer with germ-line mutations of BRCA1 appears to be more favorable than that with sporadic cases and that the disease penetrance among pedigrees with germ-line mutations of the BRCA1 gene is substantially high.

Myocardial ischemia induces differential regulation of KATP channel gene expression in rat hearts

The cardiac ATP-sensitive potassium (KATP) channel is thought to be a complex composed of an inward rectifier potassium channel (Kir6.1 and/or Kir6.2) subunit and the sulfonylurea receptor (SUR2). This channel is activated during myocardial ischemia and protects the heart from ischemic injury. We examined the transcriptional expression of these genes in rats with myocardial ischemia. 60 min of myocardial regional ischemia followed by 24-72 h, but not 3-6 h, of reperfusion specifically upregulated Kir6.1 mRNA not only in the ischemic (approximately 2.7-3.1-fold) but also in the nonischemic (approximately 2.0-2.6-fold) region of the left ventricle. 24 h of continuous ischemia without reperfusion also induced an increase in Kir6.1 mRNA in both regions, whereas 15-30 min of ischemia followed by 24 h of reperfusion did not induce such expression. In contrast, mRNAs for Kir6.2 and SUR2 remained unchanged under these ischemic procedures. Western blotting demonstrated similar increases in the Kir6.1 protein level both in the ischemic (2.4-fold) and the nonischemic (2.2-fold) region of rat hearts subjected to 60 min of ischemia followed by 24 h of reperfusion. Thus, prolonged myocardial ischemia rather than reperfusion induces delayed and differential regulation of cardiac KATP channel gene expression.