Observation of Coulomb-Assisted Nuclear Bound State of Ξ^{-}-^{14}N System

In an emulsion-counter hybrid experiment performed at J-PARC, a Ξ^{-} absorption event was observed which decayed into twin single-Λ hypernuclei. Kinematic calculations enabled a unique identification of the reaction process as Ξ^{-}+^{14}N→_{Λ}^{10}Be+_{Λ}^{5}He. For the binding energy of the Ξ^{-} hyperon in the Ξ^{-}-^{14}N system a value of 1.27±0.21  MeV was deduced. The energy level of Ξ^{-} is likely a nuclear 1p state which indicates a weak ΞN-ΛΛ coupling.

Use of a Latent Topic Model for Characteristic Extraction from Health Checkup Questionnaire Data

OBJECTIVES

When patients complete questionnaires during health checkups, many of their responses are subjective, making topic extraction difficult. Therefore, the purpose of this study was to develop a model capable of extracting appropriate topics from subjective data in questionnaires conducted during health checkups.

METHODS

We employed a latent topic model to group the lifestyle habits of the study participants and represented their responses to items on health checkup questionnaires as a probability model. For the probability model, we used latent Dirichlet allocation to extract 30 topics from the questionnaires. According to the model parameters, a total of 4381 study participants were then divided into groups based on these topics. Results from laboratory tests, including blood glucose level, triglycerides, and estimated glomerular filtration rate, were compared between each group, and these results were then compared with those obtained by hierarchical clustering.

RESULTS

If a significant (p < 0.05) difference was observed in any of the laboratory measurements between groups, it was considered to indicate a questionnaire response pattern corresponding to the value of the test result. A comparison between the latent topic model and hierarchical clustering grouping revealed that, in the latent topic model method, a small group of participants who reported having subjective signs of urinary disorder were allocated to a single group.

CONCLUSIONS

The latent topic model is useful for extracting characteristics from a small number of groups from questionnaires with a large number of items. These results show that, in addition to chief complaints and history of past illness, questionnaire data obtained during medical checkups can serve as useful judgment criteria for assessing the conditions of patients.

Cytoplasmic fine network and mitochondria in normal and abnormal cultured keratinocytes: an electron microscopic study using whole-cell observation technique

The cytoplasmic fine structures of both normal human cultured keratinocytes (NHK) and squamous cell carcinoma cells (HSC) were examined by electron microscopy using the whole-cell preparation method and stereo-viewing techniques. The presence of cytoplasmic fine network (CFN) was confirmed in both NHK and HSC, but the structures of the two were found to be radically different. In particular, the mitochondria showed a number of distinct morphological differences. The introduction of cytochalasin B and colchicine into HSC partially destroyed the CFN, and, as a result, the morphology of the HSC mitochondria changed to become similar to those of NHK. It seems that the CFN may have an important role in determining the shape of the cell organelles, such as mitochondria, and that the shape of the mitochondria may perhaps be used as an indication of cell malignancy.

Surgical treatment of patients with unruptured intracranial aneurysms

We present our experience with elective microsurgical clipping of unruptured intracranial aneurysms (UIA) and analyze this management. A total of 150 patients with UIA were reviewed and data were collected with regard to age, sex, presence of symptoms, location and size of the aneurysms, surgical complications and postoperative 1 year outcomes. Aneurysm size was assessed either by three-dimensional CT angiography or digital subtraction angiogram. Glasgow Outcome Scale was used to assess clinical outcomes. One hundred and fifty patients with 165 aneurysms were treated in this series. The mean size of the UIA was 5.6mm. Eighty aneurysms (48.5%) were less than 5mm in size, and 73 (44.2%) were from 5 to 10mm. Ten (6.1%) of the aneurysms were large and two (1.2%) were giant. One hundred and forty-three were asymptomatic and seven were symptomatic before surgery. The outcome was good in 147 patients (98%), and only three patients (2%) had a treatment-related unfavorable outcome. Five patients experienced transient neurological deficits and one patient experienced permanent neurological deficits. Overall 98.7% of the treated aneurysms were satisfactorily obliterated. Wound complications were seen only in three patients. In conclusion, UIA pose a significant challenge for neurosurgeons, where a delicate balance between benefits and possible risks must be weighed. If the requisite expertise is available, they can be treated surgically with low morbidity and a good outcome at specialized neurovascular centers.

Prediction model for glucose metabolism based on lipid metabolism

OBJECTIVES

We developed a robust, long-term clinical prediction model to predict conditions leading to early diabetes using laboratory values other than blood glucose and insulin levels. Our model protects against missing data and noise that occur during long-term analysis.

METHODS

RESULTS of a 75-g oral glucose tolerance test (OGTT) were divided into three groups: diabetes, impaired glucose tolerance (IGT), and normal (n = 114, 235, and 325, respectively). For glucose metabolic and lipid metabolic parameters, near 30-day mean values and 10-year integrated values were compared. The relation between high-density lipoprotein cholesterol (HDL-C) and variations in HbA1c was analyzed in 158 patients. We also constructed a state space model consisting of an observation model (HDL-C and HbA1c) and an internal model (disorders of lipid metabolism and glucose metabolism) and applied this model to 116 cases.

RESULTS

The root mean square error between the observed HbA1c and predicted HbA1c was 0.25.

CONCLUSIONS

In the observation model, HDL-C levels were useful for prediction of increases in HbA1c. Even with numerous missing values over time, as occurs in clinical practice, clinically valid predictions can be made using this state space model.

Preliminary evaluation of the role of surgical microscope-integrated intraoperative FLOW 800 colored indocyanine fluorescence angiography in arteriovenous malformation surgery

OBJECTIVE

To discuss the role of FLOW 800 innovative software for analytical color visualization and objective evaluation of fluorescence videos obtained by microscope-integrated intraoperative indocyanine green (ICG) fluorescence angiography in arteriovenous malformations (AVM) surgery.

MATERIALS AND METHODS

Microscope-integrated intraoperative FLOW 800 was used and evaluated in three consecutive AVM surgeries over a period of two months. The role of FLOW 800 to distinguish feeding arteries from arterialized veins and other arteries was evaluated. Its advantages and limitations over conventional intraoperative ICG angiography were evaluated.

RESULTS

This software was found to be useful in identifying arterial feeders, arterialized veins and other arteries in all the three patients and it gives additional information on the status of AVM before and after clipping suspected feeders which is sometimes difficult to interpret on conventional ICG angiography.

CONCLUSION

Flow 800 is a reliable and useful addition to microscope-integrated color ICG video angiography. Although its role is limited in deep-seated AVMs, if properly dissected and exposed it can give useful information which can be easily interpretable and reproducible.

Intraoperative near-infrared indocyanine green-videoangiography (ICG-VA) and graphic analysis of fluorescence intensity in cerebral aneurysm surgery

We present our preliminary experience with intraoperative near-infrared indocyanine green-videoangiography (ICG-VA) and analysis of blood flow dynamics using fluorescence intensity assessment in cerebral aneurysm clipping surgery. Thirty-nine patients with 43 intracranial aneurysms underwent microsurgical clipping. Intraoperative ICG-VA was performed before and after clip application. An infrared fluorescence module integrated into a surgical microscope was used to visualize fluorescence in the surgical field and we recorded the emitted fluorescent light. An integrated analytical visualization tool simultaneously analyzed the video sequence and converted it into an intensity diagram, which allowed an objective evaluation of the results rather than the subjective assessment of fluorescence using ICG-VA. Overall, ICG-VA was performed 137 times. Incomplete clipping was detected in four patients, which allowed suitable adjustment to completely obliterate the aneurysm. In 12 patients, perforators arising close to, or from, the aneurysmal neck were identified in the surgical field. In three patients, the ICG-VA intensity diagram provided valuable information leading to modification of the primary surgical maneuver. ICG-VA provides high resolution images allowing real-time assessment of the blood flow in the parent artery and arterial branches, including the perforators. The intensity diagram is useful for providing a more objective record of the hemodynamics than the traditional ICG-VA, which relies more on subjective assessment and may allow interobserver variability. We conclude that ICG-VA, combined with the intensity diagram, can reduce the morbidity and complications associated with aneurysm clipping and improve patient outcomes.

The application of intraoperative near-infrared indocyanine green videoangiography and analysis of fluorescence intensity in cerebrovascular surgery

OBJECTIVE

To evaluate the usefulness and limitations of the intraoperative near-infrared (NIR) indocyanine green videoangiography (ICG-VA) and analysis of fluorescence intensity in cerebrovascular surgery.

METHODS

Forty-eight patients received ICG-VA during various surgical procedures from May 2010 to August 2010. Included among them were 45 cases of cerebral aneurysms and 3 cases of cerebral arteriovenous malformations (AVMs). The infrared fluorescence module integrated into the surgical microscope was used to visualize fluorescent areas in the surgical field. An integrated analytical visualization tool constantly analyzed the fluorescence video sequence and generated it in the form of an intensity diagram for objective interpretation.

RESULTS

Overall, the procedure of ICG VA was done 158 times in 48 patients. There was no adverse effect of ICG dye. In cerebral aneurysm cases, the images obtained were of high resolution. In 4 cases, incomplete clipping was detected by ICG-VA and allowed suitable adjustment to completely obliterate the aneurysm. In 3 aneurysm cases, the intensity diagram of ICG VA provided valuable information. ICG-VA identified the feeding arteries, the draining veins, and nidus in all 3 AVM cases, which was confirmed by an immediate analysis of fluorescence intensity.

CONCLUSIONS

ICG-VA provides high resolution images allowing real-time assessment of the blood flow in surgical field. The intensity analysis function, in addition, is a useful adjunct to improve the accuracy of the clipping and decrease the complication rates in cerebral aneurysm cases. In cerebral AVM cases, with the help of color map and intensity diagram function, the superficial feeders, drainers, and nidus can be identified easily.

Spontaneous spinal epidural haematoma in association with Kasabach-Merritt syndrome

The authors report a case of spontaneous spinal epidural haematoma causing paraplegia secondary to thrombocytopaenia and consumptive coagulopathy from Kasabach-Merritt syndrome. The patient had long-standing multiple subcutaneous and visceral haemangiomas from childhood and developed lumbago and subsequent paraplegia. Evacuation of a spinal epidural haematoma was performed, however, the patient's neurological symptoms did not improve significantly. This case describes the potential risk of bleeding in the spinal column in patients with Kasabach-Merritt syndrome. Prompt diagnosis and management are crucial for an optimal outcome.

A Classification of Unruptured Middle Cerebral Artery Bifurcation Aneurysms that can Help in Choice of Clipping Technique

Middle cerebral artery (MCA) aneurysms comprise 20-25% of all intracranial aneurysms. The majority of middle cerebral artery aneurysms are treated by microsurgical clipping. Most of the classifications of aneurysms at present are based on size, location or pathology which are effective for the description but are less useful in preoperative planning and also in deciding on the technique or type of clip application. The aim of our study was to examine the morphological features of unruptured MCA bifurcation aneurysms which influence the techniques of clipping of these aneurysms and to attempt to subclassify unruptured middle cerebral artery aneurysms based on their preoperative 3D CTA and intraoperative characteristics so as to help in the intraoperative choice of technique and clip application, respectively. Preoperative 3D CT angiography and intraoperative images along with the record of technique and type of clips used for 141 unruptured MCA aneurysms operated at our center were studied retrospectively. Unruptured MCA bifurcation aneurysms could be subclassified into 5 types based on the similarities in their morphological features which influenced the techniques of clipping as recorded from their preoperative 3D CTA and intraoperative view. These types and the distinctive feature of each type are described. The various techniques of clipping are discussed based on these subgroups. The groups outlined make possible the establishment of a common technical approach to clipping within the groups. This classification, based on preoperative 3D CTA and intraoperative morphological features of the aneurysm and parent vessels, helps in the intraoperative choice of technique and type of clip application to tackle these lesions.

CYP3A4 and CYP2D6 inhibitory activities of Indonesian medicinal plants

Thirty samples of Indonesian medicinal plants were analyzed for their capacity to inhibit in vitro metabolism by human cytochrome P450 3A4 (CYP3A4) and CYP2D6 with a radiometric assay. The MeOH-soluble fractions of 25 samples, prepared from water extracts, demonstrated inhibitory activity more than 50% on the metabolism mediated by CYP3A4, and 21 samples on the metabolism mediated by CYP2D6. Among the MeOH-soluble fractions, Piper nigrum leaf showed the highest inhibitory activity against CYP3A4 (91.7%), and Punica granatum against CYP2D6 (98.1%). The water extracts of which MeOH-soluble fraction showed inhibitory activity more than 70% were fractionated with EtOAc. From the EtOAc-soluble fractions, Curcuma heyneana (67.0%), Pi. cubeba (75.0%), Pi. nigrum fruit (84.0%), Pi. nigrum leaf (85.8%), and Zingiber aromaticum (75.3%) demonstrated inhibitory activity more than 50% on the metabolism mediated by CYP3A4, but only Pi. nigrum fruit (72.8%) and Pi. nigrum leaf (69.1%) showed strong inhibitory activity against CYP2D6. For samples that showed more than 70% inhibition, their IC(50) values were determined. The most potent inhibitory activity against CYP3A4 (IC(50) value of 25 microg/ml) was found for the extract of Pi. nigrum leaf, while that of Catharanthus roseus showed the most potent inhibitory effect against CYP2D6 (IC(50) value of 11 microg/ml). These results should indicate once more the possibility of potential medicinal plant-drug interactions.

Combined anterior and posterior instrumentation in severe fracture-dislocation of the lower cervical spine with help of navigation: a case report

The authors report a case of severe fracture-dislocation of C6-C7 with dural and spinal cord damage causing quadriplegia. The patient was treated surgically with circumferential stabilisation. Intense spinal instrumentation with pedicle screw fixation in addition to anterior decompression and plate fixation was essential for restoring the original vertebral column. This technique of internal fixation provided a more rigid anchor, however the risk to the neurovascular structures could not be completely eliminated. Therefore, the combined anterior and posterior stabilisation assisted with a navigation system was a safer and reasonable surgical treatment for this patient with severe cervical injuries.

(S)-preferential detoxification of 4-hydroxy-2(E)-nonenal enantiomers by hepatic glutathione S-transferase isoforms in guinea-pigs and rats

In guinea-pig liver cytosol, racemic 4-hydroxy-2(E)-nonenal (HNE), a reactive and highly toxic product released from biomembranes by lipid peroxidation, was detoxified (S)-preferentially by GSH conjugation mediated by glutathione S-transferases (GSTs) and (R)-preferentially by NAD(+)-dependent oxidation mediated by aldehyde dehydrogenase (ALDH). The GST-mediated detoxification of the HNE enantiomers proceeded at much higher rates than that mediated by ALDH in guinea-pig liver cytosol. All the major guinea-pig GSTs, A1-1, M1-1, M1-2 and M1-3*, isolated from guinea-pig liver cytosol also catalysed the (S)-preferential conjugation of the HNE enantiomers. The liver and other major tissues of guinea-pigs had no immunologically detectable level of a putative GSTA4-4 orthologue, which exists as a minor GST protein in rat, mouse and human livers and exhibits extremely high catalytic activity towards HNE. All the hepatic rat GSTs, A1-1(2), A1-3, A4-4, M1-1, M1-2 and M2-2, also catalysed the (S)-preferential conjugation of HNE enantiomers.

Giant basilar bifurcation aneurysm presenting as a third ventricular mass with unilateral obstructive hydrocephalus: case report

We report a rare case of a non-ruptured basilar bifurcation aneurysm presenting as a third ventricular mass producing unilateral obstructive hydrocephalus. This is the first reported case of its kind. A 70 year old woman presented with a giant basilar bifurcation aneurysm in which the aneurysm protruded into the third ventricle as a mass causing unilateral left hydrocephalus. The patient gradually became disoriented and developed a right hemiparesis and global aphasia. The right vertebral artery was occluded by placing coils intravascularly followed by an endoscopic septostomy. The patient's neurological state dramatically improved immediately. One month after the septostomy, however, the aneurysm ruptured and the patient eventually died. Treatment of the hydrocephalus only was selected instead of direct surgery or an intravascular procedure on the aneurysm, which eventually ruptured. The mechanisms for the unilateral hydrocephalus and the rupture of the aneurysm are described. The treatment strategy for these lesions is also discussed.

Anatomical variants in the floor of the third ventricle; implications for endoscopic third ventriculostomy

Longstanding hydrocephalus and raised intracranial pressure can lead to unusual anatomical variants in the floor of the third ventricle, which may be important when performing endoscopic third ventriculostomy. Two middle aged patients with symptomatic longstanding hydrocephalus had scans that showed ventricular hydrocephalus, an empty sella, and a dilated infundibular recess which herniated into the sella turcica. Endoscopic third ventriculostomy confirmed that instead of the tuber cinerum and infundibular recess, the anterior inferior floor of the third ventricle was hanging down ventral to the pons into the sellar floor. Third ventriculostomy to the prepontine cistern was made on the dorsal wall of the dilated infundibular recess to the area surrounded by the dorsum sellae, the basilar artery trunk, and the left superior cerebellar artery, with good symptomatic control. Association of the empty sella and persistence of the infundibular recess must be carefully evaluated by MRI before attempting endoscopic third ventriculostomy. Herniation of the anterior inferior floor of the third ventricle into the empty sella can lead to loss of anatomical landmarks that require special attention during third ventriculostomy.

Surgical resection of cerebral arteriovenous malformation combined with pre-operative embolisation

To assess the importance of pre-operative embolisation, 27 cases of cerebral artriovenous malformation (AVM) treated in this institute between July 1994 and October 1998 were analysed. The patients' ages ranged from 3 to 70 years (average 36.9) with a follow-up period of 1-41 months (average 19.2). The patient presented with haemorrhage in 21 cases and seizure in five. In 21 of 27 cases, surgical resection of a nidus was performed, gamma knife therapy was applied in three and conservative therapy was chosen in three. Of 21 cases treated surgically, total removal was achieved in 19 cases and a residual nidus was seen in one (a large basal ganglia AVM). In the remaining case, postoperative angiography was not available. Pre-operative embolisation followed by surgical resection of the nidus was performed in seven cases in which there was a large AVM. A volume index was calculated to indicate the size of the nidus using X x Y x Z, where X is the maximum diameter (cm) of the nidus on the lateral angiogram, Y is the diameter (cm) perpendicular to X and Z is the maximum diameter (cm) on the anteroposter or angiogram. The index averaged 45.9 for the cases in which pre-operative embolisation was performed, while it was 5.6 in the cases without embolisation. Pre-operative embolisation was performed to reduce the nidus flow as much as possible, to prevent overload to the surrounding structures. At surgery, the nidus was resected from the surrounding tissue and care was taken not to enter the nidus. Postoperatively, the systolic blood pressure was maintained at 90-100 mmHg for several days in the intensive care unit. The results were excellent in 15 cases, good in three (hemiparesis due to the initial haemorrhage remained in all three), fair in one (a patient with a severe subarachnoid haemorrhage). Two patients died (acute pulmonary oedema and severe meningitis). Minor postoperative bleeding or oozing was seen in three cases. In conclusion, reducing the shunt flow through a nidus in a step-wise fashion with pre-operative embolisation of a large AVM seems to be quite helpful in preventing postoperative haemodynamic overload to the surrounding brain. It is also important not to enter the nidus when it is removed at surgery. This helps to prevent intraoperative and/or postoperative bleeding, and led to successful total removal of the nidus with a good postoperative course.

Xlim-1 and LIM domain binding protein 1 cooperate with various transcription factors in the regulation of the goosecoid promoter

The homeobox genes Xlim-1 and goosecoid (gsc) are coexpressed in the Spemann organizer and later in the prechordal plate that acts as head organizer. Based on our previous finding that gsc is a possible target gene for Xlim-1, we studied the regulation of gsc transcription by Xlim-1 and other regulatory genes expressed at gastrula stages, by using gsc-luciferase reporter constructs injected into animal explants. A 492-bp upstream region of the gsc promoter responds to Xlim-1/3m, an activated form of Xlim-1, and to a combination of wild-type Xlim-1 and Ldb1, a LIM domain binding protein, supporting the view that gsc is a direct target of Xlim-1. Footprint and electrophoretic mobility shift assays with GST-homeodomain fusion proteins and embryo extracts overexpressing FLAG-tagged full-length proteins showed that the Xlim-1 homeodomain or Xlim-1/Ldb1 complex recognize several TAATXY core elements in the 492-bp upstream region, where XY is TA, TG, CA, or GG. Some of these elements are also bound by the ventral factor PV.1, whereas a TAATCT element did not bind Xlim-1 or PV.1 but did bind the anterior factors Otx2 and Gsc. These proteins modulate the activity of the gsc reporter in animal caps: Otx2 activates the reporter synergistically with Xlim-1 plus Ldb1, whereas Gsc and PV.1 strongly repress reporter activity. We show further, using animal cap assays, that the endogenous gsc gene was synergistically activated by Xlim-1, Ldb1, and Otx2 and that the endogenous otx2 gene was activated by Xlim-1/3m, and this activation was suppressed by the posterior factor Xbra. Based on these data, we propose a model for gene interactions in the specification of dorsoventral and anteroposterior differences in the mesoderm during gastrulation.

4-Hydroxy-2(E)-nonenal enantiomers: (S)-selective inactivation of glyceraldehyde-3-phosphate dehydrogenase and detoxification by rat glutathione S-transferase A4-4

The glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase was irreversibly and (S)-selectively inactivated by the enantiomers of racemic 4-hydroxy-2(E)-nonenal (HNE), a reactive product released from biomembranes by lipid peroxidation in cells. Rates of the enzyme inactivations were 1.7, 3.0, and 6.0 M(-1).s(-1) for (R)-, racemic and (S)-HNEs respectively. In rat liver cytosol the HNE was detoxified 2.5-fold more (S)-selectively by GSH conjugation and 2. 4-fold more (R)-selectively by NADH-dependent reduction mediated by alcohol dehydrogenase (ADH) than the opposite enantiomers. However, in the cytosol the GSH conjugation of (R)-HNE proceeded at a much higher rate than did its ADH-mediated reduction. The minor glutathione S-transferase (GST) isoform, A4-4, in the rat (r) liver had a major role in the cytosolic (S)-selective GSH conjugation. The catalytic efficiency, k(cat)/K(m), of purified rGSTA4-4 was 4-fold higher for (S)-HNE than for (R)-HNE; the K(m) was 3-fold higher for (R)-HNE than for (S)-HNE. (S)-HNE was preferentially detoxified to (R)-HNE by rGSTA4-4 when racemic HNE was used as a substrate.

Non-ruptured large dorsal internal carotid artery aneurysm presenting with temporal quadrantanopsia

A 63-year-old woman presenting with temporal lower quadrantanopsia of the right eye was found to have a large dorsal internal carotid artery aneurysm. Large dorsal aneurysms of the internal carotid artery are rare. Lateral compression of the optic nerve by the aneurysm might damage the optic nerve at the medial side of the right optic foramen. Direct clipping surgery was performed uneventfully. Since the dome of the aneurysm was buried in the frontal lobe and also attached to the anterior skull base, a careful approach to the aneurysm with removal of the anterior clinoid process and drilling into the planum sphenoidale around the aneurysm dome was needed. The surgical strategy is discussed.

Mechanism-based inactivation of human dihydropyrimidine dehydrogenase by (E)-5-(2-bromovinyl)uracil in the presence of NADPH

Purified recombinant human dihydropyrimidine dehydrogenase (hDPD) was incubated with (14)C-labeled (E)-5-(2-bromovinyl)uracil ([(14)C]BVU) in the presence of NADPH to investigate a possible mechanism in the 18 patient deaths caused by interactions of 5-fluorouracil prodrugs with the new oral antiviral drug, sorivudine. BVU is formed from sorivudine by gut flora and absorbed through intestinal membrane. hDPD, a rate-limiting enzyme for the catabolism of 5-fluorouracil and endogenous pyrimidines in the human, was NADPH dependently radiolabeled and inactivated by [(14)C]BVU. Two radioactive tryptic fragments, I and II, isolated from radiolabeled hDPD were found by complete amino acid sequencing to originate from a common regional amino acid sequence located at positions 656 (Lys) to 678 (Arg) for I and positions 657 (Ser) to 678 (Arg) for II. However, only Cys(671), which should be present in the peptides, was not identified by amino acid sequencing. Mass spectrometric analysis of the tryptic fragments indicated that the sulfhydryl group of Cys(671) in the hDPD was modified with 5, 6-dihydro-5-(2-bromoethylydenyl)uracil (BEDU), a putative allyl bromide type of reactive molecule, to form a sulfide bond with loss of hydrogen bromide. The Cys(671) sulfide bearing the debrominated BEDU had a 5,6-dihydrouracil ring highly strained by the exocyclic double bond at the 5-position, so that it underwent facile hydrolytic ring fission with alkali and heated acid treatments. A new proposal is also made for the amino acid sequence of the pyrimidine-binding domain, including Cys(671), of DPD in the human and other species.

Prediction of in vivo drug-drug interactions based on mechanism-based inhibition from in vitro data: inhibition of 5-fluorouracil metabolism by (E)-5-(2-Bromovinyl)uracil

The fatal drug-drug interaction between sorivudine, an antiviral drug, and 5-fluorouracil (5-FU) has been shown to be caused by a mechanism-based inhibition. In this interaction, sorivudine is converted by gut flora to (E)-5-(2-bromovinyl)uracil (BVU), which is metabolically activated by dihydropyrimidine dehydrogenase (DPD), and the activated BVU irreversibly binds to DPD itself, thereby inactivating it. In an attempt to predict this interaction in vivo from in vitro data, inhibition of 5-FU metabolism by BVU was investigated by using rat and human hepatic cytosol and human recombinant DPD. Whichever enzyme was used, increased inhibition was observed that depended on the preincubation time of BVU and enzyme in the presence of NADPH and BVU concentration. The kinetic parameters obtained for inactivation represented by k(inact) and K'(app) were 2.05 +/- 1.52 min(-1), 69.2 +/- 60.8 microM (rat hepatic cytosol), 2.39 +/- 0.13 min(-1), 48.6 +/- 11.8 microM (human hepatic cytosol), and 0.574 +/- 0.121 min(-1), 2.20 +/- 0.57 microM (human recombinant DPD). The drug-drug interaction in vivo was predicted quantitatively based on a physiologically based pharmacokinetic model, using pharmacokinetic parameters obtained from the literature and kinetic parameters for the enzyme inactivation obtained in the in vitro studies. In rats, DPD was predicted to be completely inactivated by administration of BVU and the area under the curve of 5-FU was predicted to increase 11-fold, which agreed well with the reported data. In humans, a 5-fold increase in the area under the curve of 5-FU was predicted after administration of sorivudine, 150 mg/day for 5 days. Mechanism-based inhibition of drug metabolism is supposed to be very dangerous. We propose that such in vitro studies should be carried out during the drug-developing phase so that in vivo drug-drug interactions can be predicted.

Coamplification of prostate stem cell antigen (PSCA) and MYC in locally advanced prostate cancer

Gain of sequences on chromosome arm 8q is a common feature of prostate cancer that may correlate with metastatic and androgen-independent progression. The target gene(s) for this gain is not known, although MYC is amplified in a subset of advanced tumors and is one potential candidate. Prostate stem cell antigen (PSCA) is a prostate-specific cell surface protein that maps to chromosome region 8q24.2 and is overexpressed in prostate cancer. Our aim in this study was to test the hypothesis that PSCA overexpression may result from overrepresentation of chromosome arm 8q. Twenty locally advanced prostate cancers were analyzed by dual-probe fluorescence in situ hybridization (FISH) for alterations of MYC and PSCA. Extra copies of MYC were found in 12/20 (60%) tumors, including 5 (25%) with simple gain (no increase in MYC copy number relative to the chromosome 8 centromere) and 7 (35%) with an additional increase (AI or overrepresentation) in MYC copy number relative to the centromere. In the five cases with simple gain of MYC, there was a concomitant gain of PSCA. PSCA was overrepresented in 5/7 (71%) cases with AI of MYC. Immunohistochemical staining of the 20 tumors with monoclonal antibodies specific for PSCA showed a high degree of correlation between PSCA gene overrepresentation and protein overexpression. Four of 5 tumors with AI of PSCA overexpressed PSCA protein, compared with only 2/15 tumors with a normal PSCA copy number or simple gain of PSCA (P = 0.014). These results demonstrate that PSCA is co-overrepresented with MYC in a majority of cases, but may not be a necessary part of the 8q amplicon. PSCA protein overexpression can result from AI of PSCA and might be useful as a cell surface marker on prostate cancer cells with 8q overrepresentation. Genes Chromosomes Cancer 27:95-103, 2000.

[Table-moving contrast-enhanced MR angiography of abdominal aortic aneurysm]

Table-moving contrast-enhanced MR angiography (MRA) was performed in 14 cases of abdominal aortic aneurysm to evaluate its clinical usefulness. In all cases, aneurysms were clearly demonstrated and image quality was clinically acceptable. Findings of reconstructed MRA were highly consistent with those of DSA, and thrombosed areas were confirmed on source images. Main aortic branches including renal arteries, common iliac arteries, and internal and external iliac arteries were readily identified on reconstructed MRA and/or source images. Additional findings such as thoracic aortic aneurysm (n = 1), common iliac aneurysm (n = 6), external iliac aneurysm (n = 1), internal iliac aneurysm (n = 1), femoral arterial obstruction (n = 2), and femoral arterial stenosis (n = 4) were also detected. Although table-moving MRA may have disadvantages like reduced blood signal and limited spatial resolution compared with the conventional contrast-enhanced technique, the images that were obtained provided sufficient contrast and resolution for preoperative evaluation. Because abdominal aortic aneurysm is accompanied by various arterial abnormalities in many of the large arteries, table-moving MRA was considered a suitable technique for comprehensive assessment.

Cholesterol 7-hydroperoxides in rat skin as a marker for lipid peroxidation

Concentrations of cholesterol 7alpha- and 7beta-hydroperoxides (Ch 7-OOHs) in the skin of rats were determined by HPLC with a chemiluminescence detector. We demonstrated that (a) the concentrations of Ch 7-OOHs in rat skin were highly correlated with rat age (r = 0.929; N = 51, 1 to 55 weeks old), (b) the concentrations of Ch 7-OOHs in the skin of rats in an ambient light room were not significantly different from those found in rats kept in a dark room for 12 weeks, and (c) lipid peroxidation in vitro induced by ADP-Fe2+ caused an increase in the concentrations of Ch 7-OOHs in homogenates of rat skin. These results indicated that levels of Ch 7-OOHs in skin might be a good marker for aging of rats and might be independent of housing illumination, thus a good marker for endogenous lipid peroxidation. Furthermore, we observed that ultraviolet light B (UVB) irradiation markedly enhanced the concentrations of Ch 7-OOHs in the skin of rats in vivo depending on the duration of the irradiation, and the increases in Ch 7-OOHs were inhibited by radical scavengers, i.e. tocopherols. Therefore, it was suggested that the levels of Ch 7-OOHs in the skin could also be a good marker for UVB-dependent lipid peroxidation.

Photogeneration of 3beta-hydroxy-5alpha-cholest-6-ene-5-hydroperoxide in rat skin: evidence for occurrence of singlet oxygen in vivo

We identified singlet oxygen adduct of cholesterol, 3beta-hydroxy-5alpha-cholest-6-ene-5-hydroperoxide (5alpha-OOH), in skin of rats pretreated with oral doses of pheophorbide a and subsequent visible irradiation, that have been known to induce photosensitive diseases in animals and humans. In a living animal body, this is the first demonstration of presence of 5alpha-OOH, that is known to be formed exclusively by reaction in vitro between singlet oxygen and cholesterol. By the quantitative determination with high performance liquid chromatography equipped with a chemiluminescence detector, we observed time-dependent increase in concentrations of 5alpha-OOH in skin of rats pretreated with oral doses of pheophorbide a and subsequent visible irradiation, suggesting the occurrence of a labile activated oxygen species, singlet oxygen, in this system.

Marked expression of glutathione S-transferase A4-4 detoxifying 4-hydroxy-2(E)-nonenal in the skin of rats irradiated by ultraviolet B-band light (UVB)

Enzyme, Western blot, and immunohistochemical analyses indicated that rat skin cytosol contained no detectable level of the homodimeric, alpha-class glutathione S-transferase (rGST) A4-4 which catalyzes the GSH conjugation of the toxic product, 4-hydroxy-2(E)-nonenal (HNE), nonenzymatically formed from n-6 polyunsaturated fatty acid residues of lipids by lipid peroxidation. Rats irradiated by single doses (4000-24,000 mJ/cm(2)) of ultraviolet B-band light (UVB, 200 mJ/cm(2)/min) markedly expressed rGSTA4-4 in the skin at a level one-fifth that of the liver in apparent specific activity toward HNE at a single dose of 24,000 mJ/cm(2). Skin rGSTA4-4 was isolated, purified to homogeneity, and identified with hepatic rGSTA4-4 by reverse-phase partition HPLC and by amino acid sequence analysis of its CNBr fission peptides. Immunohistochemistry with polyclonal antibody raised against rGSTA4-4 demonstrated the selective expression of rGSTA4-4 in epidermis and sebaceous glands localized in dermis after UVB irradiation.

Development and evaluation of regional health database systems

We have developed information systems for regional public health in some areas. These systems have the following functions: (1) to register results of examinations, life style, follow-up data, diseases, (2) to output some reports and statistics for daily jobs, (3) to make a personal health database, (4) to display stored data by character, trend graph, radar chart or bar chart, (5) to analyze regional health problems, (6) to extract dada about persons with some conditions, (7) to compare data among some examinations, (8) to analyze risk factors. Each database can be transferred to mini-notebook type personal computers. So, they can be used anywhere and any time. Some access controls are performed for security. The systems are used in routine works, health consultation for persons and health education for groups. We have evaluated the systems and got some useful results. Using the systems, daily jobs can be performed with good accuracy and less labor, each subject can understand one's health status easily and clearly, grasps of health problems can be made quantitatively and health projects can be planned by scientific methods.

Dihydropyrimidine dehydrogenase activity and fluorouracil pharmacokinetics with liver damage induced by bile duct ligation in rats

Hepatic metabolism is the main determinant in the pharmacokinetics of 5-fluorouracil (5-FU). Its disposition might be affected with liver dysfunction. In the present study, the influence of liver damage induced by bile duct ligation on dihydropyrimidine dehydrogenase (DPD), a rate-limiting enzyme in 5-FU catabolism, CYP2B, and 5-FU pharmacokinetics were compared in male Sprague-Dawley rats. After 3 weeks of the ligation in two different groups of animals for in vitro and pharmacokinetic experiments, significant increases in serum bilirubin level and spleen weight were found in both groups. No significant differences were noted in bilirubin level or spleen weight of the bile duct ligation group between the two experiment groups. In the in vitro experiment, DPD activity and protein levels determined by Western blot analysis in the bile duct ligation group were slightly but significantly greater than those of a sham-operated group, whereas CYP2B activity and protein level were significantly reduced. These findings were supported by mRNA levels of CYP2B and DPD. When 40 mg/kg 5-FU was administered i.v. in the pharmacokinetic experiment, no significant differences in pharmacokinetic parameters were found between the bile duct ligation and sham-operated groups. These results suggested that DPD activity and protein level were maintained and that 5-FU pharmacokinetics was not altered in the presence of liver damage accompanied by a significant reduction in CYP2B activity and protein level, supporting previous clinical studies showing that mild to moderate liver dysfunction does not affect 5-FU disposition.

Increases in cholesterol 7-hydroperoxides in lipids of human skin by sunlight exposure

Free and ester forms of cholesterol 7alpha- and 7beta-hydroperoxides (Ch 7-OOHs) in skin lipids of humans were separated and determined by high performance liquid chromatography with a chemiluminescence detector. We first demonstrated the presence of Ch 7-OOHs in lipids of human skin. The levels of Ch 7-OOHs found in skin lipids of healthy Japanese volunteers (n = 5) ranged from 2.78 to 25.2 pmol/cm2 skin, indicating large inter-individual differences. However, the intra-individual differences of Ch 7-OOHs levels in skin lipids between right and left arms were less than 25% (-16.4% to 24.0%). Inter-day differences of Ch 7-OOHs in 5 subjects at 1 week interval were also small (-36.7% to 47.7%). Additionally, we investigated effects of sunlight exposure on the levels of Ch 7-OOHs in skin lipids of healthy Japanese volunteers (n = 24). The levels of Ch 7-OOHs in skin lipids significantly increased from 10.0+/-6.7 to 38.9+/-38.0 pmol/cm2 skin by sunlight exposure (10-40 mJ/cm2/min) for 3 h. Therefore, natural sunlight exposure causes lipid peroxidation in skin lipids of humans. These results suggest that the level of Ch 7-OOHs is a good marker for lipid peroxidation in human skin.

Aldehyde oxidase-dependent marked species difference in hepatic metabolism of the sedative-hypnotic, zaleplon, between monkeys and rats

A marked difference in hepatic activity of aldehyde oxidase between rats and monkeys was found to be responsible for the previously reported marked species difference in the metabolism of Zaleplon in vivo. In the postmitochondrial fractions, S-9s, from liver homogenates of these animals, Zaleplon was transformed in the presence of NADPH into the side chain oxidation product, N-desethyl-Zaleplon, and the aromatic ring oxidation product, 5-oxo-Zaleplon. In the rat S-9, N-desethyl-Zaleplon and 5-oxo-Zaleplon were a major and a very minor metabolites, respectively. However, in the monkey S-9, Zaleplon was transformed into 5-oxo-Zaleplon at a much higher rate than that for N-desethyl-Zaleplon formation. N-Desethyl-Zaleplon was formed in the monkey S-9 at a rate almost equal to that in the rat S-9. N-Desethyl-5-oxo-Zaleplon was formed at a minor rate only in the monkey S-9 through N-desethyl-Zaleplon as an obligatory intermediate. The hepatic activity for the formation of 5-oxo-Zaleplon in the monkey and rat was localized in cytosol and did not require NADPH. Sensitivity to various inhibitors and requirement of water as oxygen source, using H218O, strongly suggested that the hepatic cytosolic formation of 5-oxo-Zaleplon was mediated by aldehyde oxidase. N-Desethyl-Zaleplon was formed in the presence of NADPH by microsomes from the liver of rats and monkeys, and its formation was strongly suggested using various cytochrome P-450 inhibitors to be mediated by a number of cytochrome P-450 isoforms, such as 3A, 2C, and 2D subfamilies.

A possible mechanism of eighteen patient deaths caused by interactions of sorivudine, a new antiviral drug, with oral 5-fluorouracil prodrugs

A toxicokinetic study was performed using rats to investigate the possible mechanism of 18 acute deaths in Japanese patients with cancer and herpes zoster by interactions of the new oral antiviral drug, sorivudine (SRV), with one of the oral 5-fluorouracil (5-FU) prodrugs within 40 days after approval of the use of SRV. Tegafur, an anticancer 5-FU prodrug suggested to be used by most of the patients who died, and SRV were orally administered to rats simultaneously once daily. All of these rats died within 10 days, whereas rats given SRV or tegafur alone under the same dosage conditions showed no appreciable change over 20 days compared with controls. In the rats given both drugs, bone marrow and intestinal membrane mucosa were greatly damaged at an early stage of the coadministration, and before death, the animals showed marked decreases in white blood cell and platelet counts, diarrhea with bloody flux, and severe anorexia, as was also manifested by the patients who subsequently died. In the rats given both drugs for 6 days, extremely enhanced 5-FU levels were observed from the first day of administration in plasma and in all tissues examined, including bone marrow and intestines. The extreme enhancement of the tissue 5-FU levels was attributable to the facile inactivation by (E)-5-(2-bromovinyl)uracil (BVU) of hepatic dihydropyrimidine dehydrogenase (DPD), a key enzyme regulating the systemic 5-FU level in the rat and human. BVU, a major metabolite formed from SRV by gut flora, was found at considerable levels in the liver of rats orally administered SRV alone or SRV and tegafur, and there was a marked decrease in hepatic DPD activity. In the presence of NADPH, DPD purified from rat liver cytosol was rapidly and irreversibly inactivated by [14C]BVU as a suicide inhibitor with concomitant incorporation of the radioactivity into the enzyme protein, although SRV showed no inhibitory effect on DPD under the same conditions. Human liver DPD was recently demonstrated by us to be inactivated with BVU in a manner very similar to rat DPD.

The Ets-1 and Ets-2 transcription factors activate the promoters for invasion-associated urokinase and collagenase genes in response to epidermal growth factor

Urokinase plasminogen activator (uPA) has been associated with invasion and metastasis in breast cancer. The expression of uPA and 92 kDa type IV collagenase (gelatinase B/MMP-9) is regulated by growth factors, receptor-type tyrosine kinases and cytoplasmic oncoproteins. Here, we have identified transcriptional requirements for the induction of uPA and 92 kDa type IV collagenase by epidermal growth factor (EGF). EGF stimulates the motile and invasive activities specifically in the ErbB-2-overexpressing SK-BR-3 cells. Expression of extracellular matrix-degrading proteases including type I collagenase/MMP-1, 92 kDa type IV collagenase/MMP-9, uPA and uPA receptor were induced. EGF also transiently stimulated expression of the transcription factors Ets-1 and Ets-2. Reporter transfection assays revealed the activation of uPA and MMP-9 collagenase promoters by EGF and the requirement of each of the composite Ets and AP-1 transcription factor binding sites for an EGF response. Most notably, transfections with the Ets-1 and Ets-2 expression vectors potentiated uPA and MMP-9 promoter activation in response to EGF. Mutation of the threonine 75 residue of chicken Ets-2 conserved in the Pointed group of the Ets family proteins abrogated the ability of Ets-2 to collaborate with EGF. Ets-1 and Ets-2 were highly expressed in invasive breast tumor cell lines. Our results suggest that Ets-1 and Ets-2 provide the link connecting EGF stimuli with activation of uPA and 92 kDa type IV collagenase promoters and may contribute to invasion phenotypes.

A case of extrahepatic portal vein aneurysm with massive thrombosis: diagnosis with reconstruction images from helical CT scans

A patient with extrahepatic portal vein aneurysm with massive thrombosis, congenital in nature, is reported. Reconstructed images using curved reformation software and three-dimensional images from helical CT were useful to delineate the shape of the portal vein aneurysm and extension of the thrombi.

Guinea pig liver Mu-class glutathione S-transferase M1-2 cross-reacts with antibodies to both rat Mu- and theta-class glutathione S-transferases

Two novel major heterodimeric Mu-class glutathione (GSH) S-transferases (GSTs), designated M1-2 and M1-3*, were isolated from guinea pig (gp) liver cytosol and purified to homogeneity together with a known major homodimeric Mu-class gpGSTM1-1 (reported as GST b by R. Oshino, K. Kamei, M. Nishioka, and M. Shin, 1990, J. Biochem. 107, 105-110). These three gpGSTs were quantitatively retained on an S-hexyl-GSH affinity column and separated as homogeneous proteins by chromatofocusing. Subunits of the heterodimers were inseparable on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, but could be completely separated by reverse-phase partition high-performance liquid chromatography. A molecular cloning study demonstrated that the gpGST subunit M2 consisted of 217 amino acid residues with a calculated molecular mass of 25,562 and shared 84% identity in overall amino acid sequence with gpGSTM1-1. N-terminal amino acid sequences of peptides from the gpGST subunit M3* with a blocked N-terminus strongly suggested that it should belong to the Mu class. Western blot analysis using antisera raised against purified rat (r) GSTsA1-2 (Alpha), M1-1, P1-1 (Pi), and T2-2 (Theta) indicated that gpGSTsM1-1 and M1-3* cross-reacted only with anti-rGSTM1 antibody. However, gpGSTM1-2 cross-reacted intensely to almost the same extent with antibodies to both rGSTsM1-1 and T2-2. A homodimeric gpGSTM2-2, artificially constructed from native gpGSTM1-2 by treatment with guanidine hydrochloride followed by dialysis, intensely cross-reacted with antibodies to both the rat Mu- and Theta-class GSTs. Thus, the gpGST subunit M2 provided the first evidence for the double immuno-cross-reaction of a GST with polyclonal antibodies to two different classes of GSTs.

[Normal sternal bone marrow MRI using STIR]

The MR signal of sternal bone marrow was examined in 21 normal volunteers using a sagittal STIR sequence. Craniocaudal phase-encoding with a hand-made positioning device effectively eliminated artifacts due to cardiac pulsation. The sternal bone marrow signal could be classified into three patterns based on the signal distribution. The superior segment of the manubrium showed characteristic age-related changes. This method provided high spatial resolution and excellent bone marrow imaging. Knowledge of a normal marrow signal pattern may be useful for the evaluation of hematological disorders.

Prostate stem cell antigen: a cell surface marker overexpressed in prostate cancer

The identification of cell surface antigens is critical to the development of new diagnostic and therapeutic modalities for the management of prostate cancer. Prostate stem cell antigen (PSCA) is a prostate-specific gene with 30% homology to stem cell antigen 2, a member of the Thy-1/Ly-6 family of glycosylphosphatidylinositol (GPI)-anchored cell surface antigens. PSCA encodes a 123-aa protein with an amino-terminal signal sequence, a carboxyl-terminal GPI-anchoring sequence, and multiple N-glycosylation sites. PSCA mRNA expression is prostate-specific in normal male tissues and is highly up-regulated in both androgen-dependent and -independent prostate cancer xenografts. In situ mRNA analysis localizes PSCA expression in normal prostate to the basal cell epithelium, the putative stem cell compartment of the prostate. There is moderate to strong PSCA expression in 111 of 126 (88%) prostate cancer specimens examined by in situ analysis, including high-grade prostatic intraepithelial neoplasia and androgen-dependent and androgen-independent tumors. Flow cytometric analysis demonstrates that PSCA is expressed predominantly on the cell surface and is anchored by a GPI linkage. Fluorescent in situ hybridization analysis localizes the PSCA gene to chromosome 8q24.2, a region of allelic gain in more than 80% of prostate cancers. A mouse homologue with 70% amino acid identity and similar genomic organization to human PSCA has also been identified. These results support PSCA as a target for prostate cancer diagnosis and therapy.

Suicidal inactivation of human dihydropyrimidine dehydrogenase by (E)-5-(2-bromovinyl)uracil derived from the antiviral, sorivudine

An enzymatic study was performed to clarify the mechanism of 18 acute deaths in patients who had received the new oral antiviral drug, sorivudine (SRV), during anticancer chemotherapy with 5-fluorouracil (5-FU) prodrugs. Human dihydropyrimidine dehydrogenase (hDPD), playing a key role in the liver as the rate-limiting enzyme in catabolism of 5-FU, was expressed in E. coli, purified and incubated in the presence of NADPH with SRV or (E)-5-(2-bromovinyl)uracil (BVU), a metabolite of SRV produced by human gut flora. hDPD was rapidly and irreversibly inactivated by BVU, but not by SRV. Radioactivity of [14C]BVU was incorporated into hDPD in the presence of NADPH in a manner reciprocal to the enzyme inactivation. In the absence of NADPH, hDPD was not inactivated by BVU, nor radiolabeled with [14C]BVU. Thus, as we demonstrated previously with studies using the rat, the acute deaths were strongly suggested to be attributable to markedly elevated tissue 5-FU levels which were responsible for irreversible inhibition of hDPD by covalent binding of a reduced form of BVU as a suicide inactivator.

Cellular interpretation of multiple TGF-beta signals: intracellular antagonism between activin/BVg1 and BMP-2/4 signaling mediated by Smads

During early embryogenesis of Xenopus, dorsoventral polarity of the mesoderm is established by dorsalizing and ventralizing agents, which are presumably mediated by the activity of an activin/BVg1-like protein and Bone Morphogenetic Proteins (BMP), respectively. Interestingly, these two TGF-beta subfamilies are found in overlapping regions during mesoderm patterning. This raises the question of how the presumptive mesodermal cells recognize the multiple TGF-beta signals and differentially interpret this information to assign a particular cell fate. In this study, we have exploited the well characterized model of Xenopus mesoderm induction to determine the intracellular interactions between BMP-2/4 and activin/BVg1 signaling cascades. Using a constitutively active BMP-2/4 receptor that transduces BMP-2/4 signals in a ligand-independent fashion, we demonstrate that signals provided by activin/BVg1 and BMP modulate each other's activity and that this crosstalk occurs through intracellular mechanisms. In assays using BMP-2/4 and activin/BVg1-specific reporters, we determined that the specificity of BMP-2/4 and activin/BVg1 signaling is mediated by Smad1 and Smad2, respectively. These Smads should be considered as the mediators of the intracellular antagonism between BMP-2/4 and activin/BVg1 signaling possibly through sequestration of a limited pool of Smad4. Consistent with such a mechanism, Smad4 interacts functionally with both Smad1 and −2 to potentiate their signaling activities, and a dominant negative variant of Smad4 can inhibit both activin/BVg1 and BMP-2/4 mediated signaling Finally, we demonstrate that an activin/BVg1-dependent transcriptional complex contains both Smad2 and Smad4 and thereby provides a physical basis for the functional involvement of both Smads in TGF-beta-dependent transcriptional regulation. Thus, Smad4 plays a central role in synergistically activating activin/BVg1 and BMP-dependent transcription and functions as an intracellular sensor for TGF-beta-related signals.

[Lethal drug interactions of the new antiviral, sorivudine, with anticancer prodrugs of 5-fluorouracil]

In 1993 eighteen Japanese patients with cancer and herpes zoster, a viral disease, died from interactions of the new oral antiviral drug, sorivudine (SRV: 1-beta-D-arabinofuranosyl-(E)-5-(2-bromovinyl)uracil), with oral anticancer prodrugs of 5-fluorouracil (5-FU) within 40 d after SRV was approved by the Japanese government and began to be used clinically. Before the death, most of these patients had severe symptoms of toxicity, including diarrhea with bloody flux and marked decreases in white blood cell and platelet counts. All of these patients received SRV daily for several days while being administered long-term anticancer chemotherapy with one of the oral 5-FU prodrugs. There was no acute toxic symptom in patients who received SRV alone or SRV and the other types of anticancer drugs. A toxicokinetic study was carried out using rats to investigate the mechanism of the acute death in the patients caused by drug interactions between SRV and 5-FU prodrugs. Rats were orally coadministered SRV with tegafur (FT: 1-(2-tetrahydrofuryl)-5-fluorouracil), a 5-FU prodrug that most of the patients were considered to receive before the death. All the rats receiving SRV and FT once daily showed extremely elevated levels of 5-FU in the plasma and tissues, including bone marrow and small intestines, and died within 10 d, while the animals given the same repeated dose of SRV or FT alone were still alive over 20 d without any appreciable toxic symptom. Before their death, there were a marked damage of bone marrow, a marked atrophy of intestinal membrane mucosa, marked decreases in white blood cells and platelets, diarrhea with bloody flux, and severe anorexia as reported for the patients. Data obtained by in vivo and in vitro studies indicated that (E)-5-(2-bromovinyl)uracil (BVU), generated from SRV by the gut flora and absorbed through the intestinal membrane, was reduced in the presence of NADPH to a reactive form by hepatic dihydropyrimidine dehydrogenase (DPD), a key enzyme regulating the tissue 5-FU levels from FT, bound covalently to DPD as a suicide inhibitor, and markedly retarded the catabolism of 5-FU. An irreversible inactivation by BVU of rat and human DPDs, expressed in E. coli for the latter, was observed in the presence of NADPH with their purified preparations in a manner reciprocal to radiolabelling of the enzyme proteins with [14C]BVU. SRV showed no inhibitory effect on the rat and human DPDs in the presence of NADPH.

Rat liver theta-class glutathione S-transferases T1-1 and T2-2: their chromatographic, electrophoretic, immunochemical, and functional properties

A method was established for simultaneously isolating Theta-class glutathione (GSH) S-transferases (GSTs) T1-1 and T2-2 as homogeneous proteins from rat (r) liver cytosol. The established method of using an 8-aminooctyl Sepharose 4B column to separate rGSTT1-1 from rGSTT2-2 at the final stage of their purification was a modification of the method previously reported for the isolation of rGSTT2-2 (Hiratsuka et al., J. Biol. Chem., 265, 11973-11981, 1990). Specific substrates used for purification of the Theta-class rGSTs were dichloromethane for T1-1 and 5-sulfoxymethylchrysene for T2-2. rGSTsT1-1 and T2-2 existed at a ratio of 1:7 at a total concentration of 0.5% of that of the cytosolic protein. Purified rGSTsT1-1 and T2-2 were separated as single bands at 28 and 26.5 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and as single peaks at retention times of 36 and 34 min, respectively, by reverse-phase partition high-performance liquid chromatography on a microBondasphere column eluted with a linear gradient of acetonitrile in water containing trifluoroacetic acid. Western blot analysis indicated that rabbit antisera raised against rGSTsT1-1 and T2-2 intensely reacted with the corresponding antigens, but showed no detectable reactivity with the different isoforms of Theta-class rGSTs as well as with representative hepatic rGSTs of other classes. The Theta-class rGSTs showed higher GSH peroxidase activity than rGSTA1-2 toward hydroperoxides of cumene, arachidonic acid, and linoleic acid. Cumene hydroperoxide was a better substrate for rGST T1-1 than for rGST T2-2, while the fatty acid hydroperoxides were the better substrates for rGST T2-2 than for rGST T1-1.

Changes in the hepatic glutathione peroxidase redox system produced by coplanar polychlorinated biphenyls in Ah-responsive and -less-responsive strains of mice: mechanism and implications for toxicity

The alteration in hepatic glutathione peroxidase (GPx) produced by polychlorinated biphenyls (PCBs) was studied in vivo in aryl hydrocarbon (Ah)-responsive C57BL and -less-responsive DBA strains of mice. 3,3',4,4',5-Pentachlorobiphenyl (PCB 126), one of the high-affinity ligands for the Ah receptor, significantly reduced Se-dependent GPx activity in C57BL mice, but not in DBA mice. A reduction in activity in C57BL mice was also observed following treatment with a high dose of 3,3',4,4'-tetrachlorobiphenyl with lesser affinity for the Ah receptor than PCB 126, but not by 2,2',5,5'-tetrachlorobiphenyl, a low-affinity ligand. To assess the effects on GPx in the liver, the content of reduced glutathione (GSH), an obligate co-factor for GPx, and the activity of two enzymes, γ-glutamyl transpeptidase (γ-GTP) and glutathione reductase (GR), which play a role in supplying GSH were determined after PCB treatment. The results showed that although the hepatic activity of γ-GTP and GR was affected differently by PCB 126, the content of GSH was slightly increased rather than reduced in both strains of mice. The activity of non-Se-dependent GPx, which is due to the catalysis by some isozymes of glutathione S-transferase (GST), was significantly increased only in C57BL mice by PCB 126 treatment. Immunoblot analysis demonstrated that the induction of the class θ GST, which is a potent reducer of peroxides (Hiratsuka et al., 1995. Biochem. Biophys. Res. Commun. 212, 743) reflects the enhancement of the above activity. These results suggest that (i) the PCB-induced reduction in Se-dependent GPx activity is mediated by a mechanism involving the Ah receptor; and (ii) a concomitant increase in the class θ GST partially rescues the Ah-responsive mice from coplanar PCB-induced oxidative stress.

[Magnetization transfer MR of cerebrovascular disorders using calculated images]

This study applied a magnetization transfer contrast method to patients with cerebrovascular disorders. A 1.5T superconducting MR unit was used, and magnetization transfer ratio (MTR) images were calculated by evaluating two paired images before and after off-resonance gradient echo pulse sequences. The normal white matter showed the highest MTRs, CSF the lowest, and gray matter, intermediate. Cerebral ischemic patients showed two patterns according to the chronological stage of the affected area. Lesions in the acute and subacute stages revealed higher transfer rates than those in the chronic stage. Patients with cerebral hemorrhage were divided into three groups: the hyperacute group showed a low transfer pattern; the acute group presented inhomogeneous high transfer rates; and the subacute group showed remarkably low transfer rates. In the acute and subacute ischemic stages, increased macromolecules caused higher MTRs than in the chronic stage. In hemorrhagic groups, low MTRs in subacute hemorrhage reflected the transfer of methemoglobin. High MTRs in acute hemorrhage with rich deoxyhemoglobin suggested increased fibrin, plasma, and serum components of macromolecules. The MTC method provided new chronological information on cerebral hemorrhage, adding to that provided by routine MR images.