Synthesis and antitumor activity of 1-[2-(chloroethyl)-3-(2-substituted-10H-phenothiazin-10-yl)alkyl- 1-urea s as potent anticancer agents

10-[N-(Phthalimido)alkyl]-2-substituted-10H-phenothiazines and 1-(2-chloroethyl)-3-(2-substituted-10H-phenothiazin-10-yl)alkyl-1- ureas were synthesized and found to have antiproliferative effects on human HEp-2 and L5178Y cell cultures. The multi-drug resistant subline of mouse lymphoma was sensitive to the reversal effects of some 10-[N-(phthalimido)alkyl]-2-substituted-10H-phenothiazines, while 1-(2-chloro-ethyl)-3-(2-substituted-10H-phenothiazin-10-yl)alkyl-1 -ureas were less effective but had a similar degree of antiproliferative effect on both cell lines.

Crystal structure of L-2-haloacid dehalogenase from Pseudomonas sp. YL. An alpha/beta hydrolase structure that is different from the alpha/beta hydrolase fold

L-2-Haloacid dehalogenase catalyzes the hydrolytic dehalogenation of L-2-haloalkanoic acids to yield the corresponding D-2-hydroxyalkanoic acids. The crystal structure of the homodimeric enzyme from Pseudomonas sp. YL has been determined by a multiple isomorphous replacement method and refined at 2.5 A resolution to a crystallographic R-factor of 19.5%. The subunit consists of two structurally distinct domains: the core domain and the subdomain. The core domain has an alpha/beta structure formed by a six-stranded parallel beta-sheet flanked by five alpha-helices. The subdomain inserted into the core domain has a four helix bundle structure providing the greater part of the interface for dimer formation. There is an active site cavity between the domains. An experimentally identified nucleophilic residue, Asp-10, is located on a loop following the amino-terminal beta-strand in the core domain, and other functional residues, Thr-14, Arg-41, Ser-118, Lys-151, Tyr-157, Ser-175, Asn-177, and Asp-180, detected by a site-directed mutagenesis experiment, are arranged around the nucleophile in the active site. Although the enzyme is an alpha/beta-type hydrolase, it does not belong to the alpha/beta hydrolase fold family, from the viewpoint of the topological feature and the position of the nucleophile.

The excitatory and inhibitory modulation of primary afferent fibre-evoked responses of ventral roots in the neonatal rat spinal cord exerted by nitric oxide

1. We investigated the role of nitric oxide (NO) in modulating spinal synaptic responses evoked by electrical and noxious sensory stimuli in the neonatal rat spinal cord in vitro. 2. Potentials were recorded extracellularly from a ventral root (L3-L5) of the isolated spinal cord preparation or spinal cord-saphenous nerve-skin preparation of 0- to 2-day-old rats. Spinal reflexes were elicited by electrical stimulation of the ipsilateral dorsal root or by noxious skin stimulation. 3. In the spinal cord preparation, single shock stimulation of a dorsal root at C-fibre strength induced mono-synaptic reflex followed by a slow depolarizing response lasting about 30 s (slow ventral root potential; slow VRP) in the ipsilateral ventral root of the same segment. Bath-application of NO gas-containing medium (10(-4)- 10(-2) dilution of saturated medium) and NO donors, 1-hydroxy-2-oxo-3-(N-ethyl-2-aminoethyl)-3-ethyl-1-triazene (NOC12, 3-300 microM), S-nitroso-N-acetyl-D,L-penicillamine (SNAP, 3-300 microM) and S-nitroso-L-glutathione (GSNO, 3-300 microM), produced an inhibition of the slow VRP and a depolarization of ventral roots. Another NO donor, 3-morpholinosydononimine (SIN-1, 30-300 microM), also depressed the slow VRP but did not depolarize ventral roots. These agents did not affect the mono-synaptic reflex. 4. In the spinal cord-saphenous nerve-skin preparation, application of capsaicin (0.1-0.2 microM) to skin evoked a slow depolarizing response of the L3 ventral root. This slow VRP was depressed by NOC12 (10-300 microM) and SIN-1 (100-300 microM). When the concentration of NOC12 was increased to 1 mM, spontaneous synaptic activities were augmented and the depressant effect of NOC12 on the slow VRP became less pronounced. 5. A NO-scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide( carboxy- PTIO, 100-300 microM) prevented the depressant effect on the dorsal root-evoked slow VRP and ventral root depolarizing effects of NO donors. Carboxy-PTIO increased spontaneous synaptic activities and markedly potentiated the slow VRP. A NO synthase (NOS) inhibitor, N omega-nitro-L-arginine methyl ester (L-NAME, 0.03-1 microM), but not D-NAME (0.03-1 microM), also markedly potentiated the slow VRP and this effect was reversed by L-arginine (300 microM). 6. 8-Bromo-cyclic guanosine 3': 5'-monophosphate (8-Br-cyclic GMP, 100-300 microM) produced both an inhibition of the slow VRP and a depolarization of ventral roots. A cyclic GMP-dependent protein kinase inhibitor, KT5823 (0.3 microM), partly inhibited the depressant effects of NO donors and 8-Br-cyclic GMP on the dorsal root-evoked slow VRP. In contrast, KT5823 did not inhibit the depolarizing effects of NO donors. 7. Perfusion of the spinal cord with medium containing tetrodotoxin (0.3 microM) and/or low Ca2+ (0.1 mM)-high Mg2+ (10 mM) markedly potentiated the depolarizing effect of NO donors. The SNAP-evoked depolarization in the tetrodotoxin-containing low Ca(2+)-high Mg2+ medium was significantly inhibited by excitatory amino acid receptor antagonists D-(-)-2-amino-5-phosphonovaleric acid (30 microM) and 6-cyano-7-nitroquinoxaline-2,3-dione (10 microM). 8. The present study suggests that inhibitory and excitatory mechanisms meditated by the NO-cyclic GMP cascade are involved in the primary afferent fibre-evoked nociceptive transmission in the neonatal rat spinal cord. The inhibitory mechanism, but not the excitatory mechanism, appears to be partly mediated by cyclic GMP-dependent protein kinase. It is also suggested that Ca(2+)-independent release of excitatory amino acid neurotransmitters contributes to the depolarizing response to NO of ventral roots.

[Regional left ventricular contraction kinetics in patients with hypertrophic cardiomyopathy: investigation by ECG-gated myocardial SPECT with 99mTc-MIBI]

To investigate the regional left ventricular (LV) contraction kinetics in patients with hypertrophic cardiomyopathy (HCM), we performed ECG gated myocardial tomography (gated-SPECT) with 99mTc methoxy-2-isobutyl isonitrile (MIBI) at rest in 11 patients with HCM and 13 normal subjects. In order to evaluate regional LV contraction kinetics, multi-plane long axial tomograms were constructed and LV was divided into 17 segments. From the time activity curve of myocardial count, percent change during systole (%CC) was calculated in each segment. Normal range of %CC in each segment was derived from normal files. Systolic asynchrony in each patient was expressed as SD (standard deviation) of R-wave to peak count (R-PC) intervals of 17 segments. Decreased %CC was observed in 87 of 187 segments (47%) in HCM (8 +/- 5 segments/patient, range; 2-14 segments/patient). SD in patients with HCM was significantly greater than that in normal subjects (5.9 +/- 1.3 vs. 3.5 +/- 0.6, p < 0.01). The extent of decreased %CC in patients with HCM correlated well with global 123I-BMIPP (BMIPP) uptake and the extent of regional abnormality of BMIPP (Defect Score) (r = -0.79, r = 0.88 each, p < 0.01). On the other hand, SD correlated well with left ventricular (LV) filling rate during early diastole (r = -0.66, p < 0.01). Patients with HCM were divided into 2 groups whether LV ejection fraction (EF) increased (Group 1) or decreased (Group 2) by exercise stress. SD in Group 2 was significantly greater than that in Group 1. In segments with decreased %CC, the distribution of R-PC interval was different with that in segments with normal %CC. These results suggested that indexes which were derived from gated-SPECT with MIBI could bring several informations which were important to assess the pathologic condition of HCM.

Cloning and functional expression of mCCR2, a murine receptor for the C-C chemokines JE and FIC

The C-C chemokines human monocyte chemoattractant protein-1 and -3 (MCP-1 and MCP-3) and mouse JE and FIC are potent activators of monocytes. Several receptors for MCP-1 and MCP-3 have been cloned from human monocytic cell lines, and one of these receptors, CCR2B, binds both MCP-l and MCP-3. Thus far, no murine receptors for JE or FIC have been reported. We have cloned a novel murine C-C chemokine receptor, designated mouse CCR2 (mCCR2), from the mouse monocyte cell line WEHI265.1. The predicted 373-amino acid sequence of mCCR2 shows highest identity (80%) with CCR2B. When stably expressed in human embryonic kidney 293 cells, mCCR2 specifically bound 125I-JE with high affinity. FIC was less potent than JE in competing 125I-JE binding to mCCR2-expressing cells, while three other mouse chemokines, MIP-1alpha, C10, and N51/KC, did not compete. mccr2 mRNA expression was detected in elicited peritoneal macrophages as well as in several mouse organs. The cloning of mCCR2 provides an important tool to investigate monocyte/macrophage responses to JE and FIC, to identify other targets for their action, and potentially to study models of CCR2 function in the mouse.

Meisenheimer rearrangement of azetopyridoindoles. VIII. Synthesis and antiviral activities of 12-carbaeudistomin analogs

Eudistomins, isolated from the colonial tunicate Eudistoma olivaceum, have been a synthetic target due to their strong antiviral activity against Herpes simplex virus (HSV-1) and activities against certain types of tumors in vivo. In order to examine the structure-activity relationship of eudistomins, 12-carbaeudistomin analogs were synthesized and their activities against influenza A and B virus, HSV-1, HSV-2 and human cytomegalovirus were investigated. Among them, racemic 6-methoxy-12-carbaeudistomin showed similar activity to (-)-debromoeudistomin K, synthesized as a control compound.

Crystallization and preliminary x-ray crystallographic studies of L-2-haloacid dehalogenase from Pseudomonas sp. YL

The dimeric L-2-haloacid dehalogenase from Pseudomonas sp. YL, (subunit mass, 26179 Da), has been crystallized by vapor diffusion, supplemented by repetitive seeding, against a 50 mM potassium dihydrogenphosphate solution (pH 4.5) containing 15% (w/v) polyethylene glycol 8,000 and 1% (v/v) n-propanol. The crystals belong to the monoclinic space group C2 with unit cell dimensions of a = 92.21 angstrom, b = 62.78 angstrom, c = 50.84 angstrom, and beta = 122.4 degrees, and contain two dehalogenase dimers in the unit cell. They are of good quality and diffract up to 1.5 angstrom resolution.

Relationship between resonance energy per pi-electron and carcinogenicity in arenes

The resonance energy per pi-electron of various arenes was calculated using Aihara's TRE theory. There seemed to be a correlation between the resonance energy volume per pi-electron of the cation species (lacking a carbon atom) with the highest approximate superdelocalizability (Sr'(E)) from the parent skeleton and carcinogenicity, i.e. the induction of cancer by arenes (three-ring, four-ring, five-ring, six-ring and seven-ring) seems to be dependent on the resonance energy per pi-electron in they contain).

[Myocardial sympathetic activity and characteristics in hypertrophic cardiomyopathy: comparison with hypertensive hypertrophy]

The characteristics of myocardial sympathetic activity were studied using myocardial imaging with I-123-metaiodobenzylguanidine (MIBG) in 16 patients with hypertrophic cardiomyopathy (HCM), 12 patients with essential hypertension and left ventricular hypertrophy (HT) and 10 normal subjects. Myocardial imaging with MIBG and thallium-201 (T1) was performed at rest on a separate day. The index of myocardial MIBG uptake, "uptake ratio", was calculated from the percentage uptake of MIBG and T1. Reduction of myocardial MIBG during 3 hours (percentage washout) was also calculated. The extent of the defect was quantitatively assessed (defect score) from the bull's eye map. Global "uptake ratio" of the delayed image decreased in the order of normal subjects, patients with HT and those with HCM (p < 0.01). Defects in MIBG images were observed in all patients with HCM and 92% in those with HT. The defects were located in the inferior and lateral segments in patients with HT, but around the entire left ventricle in patients with HCM. Both groups had smaller regional "uptake ratio" than normal subjects, but HT and HCM demonstrated different behaviors: reduced in the inferior and lateral segments as compared with other segments in HT, but distributed equally in all segments in HCM. In patients with HCM, percentage washout was significantly accelerated in comparison with patients with HT and normal subjects in both global and regional analyses, but there was no difference between the latter two groups. Disturbance of myocardial sympathetic activity observed in patients with HCM by MIBG uptake and washout differed from that caused by HT.

Partial purification and characterization of a protein kinase that is activated by nuclear localization signal peptides

A nuclear localization signal (NLS) is required for the transport of karyophilic proteins from the cytoplasm to the nucleus. In this study, NLS was examined in terms of its effect on diverse cellular functions such as protein phosphorylation reactions. When synthetic peptides containing the NLS of SV40 T-antigen were injected into the cytoplasm of Xenopus oocytes, and the oocytes incubated with [32P]phosphorous-containing medium, a 32 kDa protein was found to be preferentially phosphorylated in an NLS-dependent manner. The incubation of fractionated cytosolic extracts prepared from mouse Ehrlich ascites tumor cells with [gamma-32P]ATP in the presence of the NLS peptides, results in the stimulation of the phosphorylation of several proteins. Similar in vitro stimulation was observed by other functional NLS peptides such as those of polyoma virus T-antigen and nucleoplasmin. Little or no stimulation, however, was detected for peptides of mutant type and reverse type NLS of SV40 T-antigen, and the C-terminal portion of lamin B. Using an in vitro assay, the phosphorylation activity was fractionated chromatographically and a fraction was obtained which contained a high level of activity. The fraction was found to contain three major proteins having molecular masses of 95, 70, and 43 kDa. The in vivo and in vitro results are consistent with the existence of a protein kinase, called NLS kinase, that is specifically activated by NLS peptides.

[Assessment of left ventricular contraction kinetics by ECG-gated myocardial SPECT with 99mTc-MIBI: a new attempt with multi-plane long axial tomography]

To investigate left ventricular (LV) contraction kinetics, we performed ECG gated myocardial tomography (gated-SPECT) with 99mTc-MIBI (99mTc methoxy-2-isobutyl isonitrile) at rest. Data were obtained from 32 views and R-R interval was divided into 16. To clarify whether myocardial count change during systole (%CC) reflected LV wall thickening (%WT), we compared septal and posterior %CC in short axis image with %WT which were obtained by echocardiography. And %CC correlated well with %WT (r = 0.86, p < 0.01). In order to assess myocardial contraction kinetics in various parts of LV, multi-plane long axial tomograms were constructed in 10 normal subjects and 9 patients with myocardial infarction (MI). By multi-plane long axial tomography, LV was divided into 17 segments. In each segment %CC was calculated from time activity curves of myocardial count of 99mTc-MIBI. And the disparity of the appearance of peak count in each segment was also observed. In normal subjects %CC was greatest at apex and they decreased from apex to cardiac base. Besides %CC at lateral segments was greater than that in septal segments. Normal range of %CC was determined segment by segment. In normal subjects the intervals from ECG R-wave to peak count were not different in each segment. But in patients with MI they distributed in wide range and prolonged intervals were observed in segments with rest perfusion defect (infarcted segment). In patients with MI decreased %CC was observed in 91% of infarcted segments, in 83% of the segments with exercise induced ischemia and in 89% of the segments with 123I-BMIPP defects. These results indicated decreased %CC represented viable but compromised myocardium as well as necrotic myocardium. In gated-SPECT we obtained useful informations in addition to myocardial perfusion. But it took more than 30 minutes to perform. More experience will be necessary to ascertain the value of this technique.

Growth regulation of endothelial cells by tissue fragments: analysis on mechanism of rapid endothelialization of tissue-seeded vascular prosthesis in a three-dimensional culture system

Rapid endothelialization of the inner surface was reported in an autologous tissue-seeded vascular prosthesis. We applied a three-dimensional in vitro culture system to elucidate the precise mechanism of rapid endothelial coverage of a tissue-seeded vascular prosthesis. Human venous, omental, adipose and striated muscle tissue fragments were harvested from surgical specimens. They were embedded in collagen gel, and 2.0 x 10(5) bovine aortic endothelial cells (BAECs) were seeded on the gel. The number of BAECs was counted on Days 2 and 7. Growth rate of BAECs was facilitated on the collagen gel with omental and striated muscle tissue fragments (p < 0.05). Factor VIII-negative spindle cells migrated around tissue fragments, especially around the omental and striated muscle tissue fragments. Rapid endothelialization of a tissue-seeded vascular prosthesis may result from facilitation of EC proliferation by viable tissue fragments and migrated cells. These results confirm tissue fragments regulate EC growth, and are useful as bioengineering tools.

Purification and properties of a plant beta-D-glucuronidase form Scutellaria root

beta-D-Glucuronidase (baicalinase, GUS [EC 3.2.1.31]) activity in the crude drug, Scutellaria root, was assayed in line with the quality control standards of Kampo (Japanese Herbal) medicines. GUS was purified to homogeneity in the purification steps including DEAE-Sepharose Fast Flow and chromatofocusing used PBETM94 and Polybuffer 74. These results suggest that the Scutellaria GUS is composed of 55kDa active subunits and that the isoelectric point of this enzyme is pH 5.4. Optimal catalytic activity was found at pH 4.7 in the pH range 3.6--6.2 in 50 mM Na-citrate buffer. The purified enzyme hydrolyzed baicalin and wogonin glucuronide, but did not hydrolyze glycyrrhizin or some beta-glucosides found in other crude drugs. GUS activity in several crude drugs is also described.

Overexpression and feasible purification of thermostable L-2-halo acid dehalogenase of Pseudomonas sp. YL

The gene encoding thermostable L-2-halo acid dehalogenase of Pseudomonas sp. YL was isolated, and its overexpression system was constructed. Gene library was prepared from Sau3AI fragments of total DNA from Ps. sp. YL, pUC118 as a vector and Escherichia coli JM109 as a host. The recombinant cells resistant to bromoacetate, a germicide, were isolated and shown to produce L-2-halo acid dehalogenase. Subsequently, subcloning was carried out with pKK223-3 as a vector, and the length of DNA inserted was reduced to 1.1 kbp. One of the subclones showed very high activity, and the amount of the dehalogenase produced corresponded to about 30% of the soluble protein. From 5 g (wet weight) of cells, 105 mg of dehalogenase was efficiently purified by heat treatment and DEAE-Toyopearl chromatography. This overexpression system provides a large amount of the thermostable enzyme to enable us to study the properties, structure and application of the enzyme.

Reaction mechanism of L-2-haloacid dehalogenase of Pseudomonas sp. YL. Identification of Asp10 as the active site nucleophile by 18O incorporation experiments

L-2-Haloacid dehalogenase (EC 3.8.1.2) catalyzes the hydrolytic dehalogenation of L-2-haloacids to produce the corresponding D-2-hydroxy acids. We have analyzed the reaction mechanism of the enzyme from Pseudomonas sp. YL and found that Asp10 is the active site nucleophile. When the multiple turnover enzyme reaction was carried out in H2(18)O with L-2-chloropropionate as a substrate, lactate produced was labeled with 18O. However, when the single turnover enzyme reaction was carried out by use of a large excess of the enzyme, the product was not labeled. This suggests that an oxygen atom of the solvent water is first incorporated into the enzyme and then transferred to the product. After the multiple turnover reaction in H2(18)O, the enzyme was digested with lysyl endopeptidase, and the molecular masses of the peptide fragments formed were measured by an ionspray mass spectrometer. Two 18O atoms were shown to be incorporated into a hexapeptide, Gly6-Lys11. Tandem mass spectrometric analysis of this peptide revealed that Asp10 was labeled with two 18O atoms. Our previous site-directed mutagenesis experiment showed that the replacement of Asp10 led to a significant loss in the enzyme activity. These results indicate that Asp10 acts as a nucleophile on the alpha-carbon of the substrate leading to the formation of an ester intermediate, which is hydrolyzed by nucleophilic attack of a water molecule on the carbonyl carbon atom.

Free snuff-box flap for reconstruction of the wrap-around flap donor site

The big toe donor site of the wrap-around flap has been reconstructed immediately after elevation of the flap with a snuff-box flap from the dorsum of the recipient hand in 6 patients. Rapid wound healing and a satisfactory appearance were achieved.

Use of NK1 receptor antagonists in the exploration of physiological functions of substance P and neurokinin A

Tachykinin NK1 receptor antagonists were used to explore the physiological functions of substance P (SP) and neurokinin A (NKA). Pharmacological profiles of three NK1 receptor antagonists, GR71251, GR82334, and RP 67580, were examined in the isolated spinal cord preparation of the neonatal rat. These tachykinin receptor antagonists exhibited considerable specificities and antagonized the actions of both SP and NKA to induce the depolarization of ventral roots. Electrical stimulation of the saphenous nerve with C-fiber strength evoked a depolarization lasting about 30 s of the ipsilateral L3 ventral root. This response, which is referred to as saphenous-nerve-evoked slow ventral root potential (VRP), was depressed by these NK1 receptor antagonists. In contrast, the saphenous-nerve-evoked slow VRP was potentiated by application of a mixture of peptidase inhibitors, including thiorphan, actinonin, and captopril in the presence of naloxone, but not after further addition of GR71251. Likewise, in the isolated coeliac ganglion of the guinea pig, electrical stimulation of the mesenteric nerves evoked in some ganglionic cells slow excitatory postsynaptic potentials (EPSPs), which were depressed by GR71251 and potentiated by peptidase inhibitors. These results further support the notion that SP and NKA serve as neurotransmitters producing slow EPSPs in the neonatal rat spinal cord and guinea pig prevertebral ganglia.

[A case of advanced gastric cancer successfully treated with combination chemotherapy using THP, 5'-DFUR and CDDP, followed by surgical resection]

We reported a patient with advanced gastric cancer and a liver metastasis, who responded remarkably to combination chemotherapy using THP, 5'-DFUR and CDDP. The patient was administered four courses of THP (15 mg/m2/day, on day 1, iv), 5'-DFUR (1400 mg/m2/day, on days 1-4 and 15-18, orally), and CDDP (80 mg/m2/day, on day 5, iv) every 4 weeks. As a result, both the primary and metastatic tumors decreased remarkably in size at more than 19 weeks (PR) and we performed curative total resection of the stomach and partial resection of the liver. Histologically, the effects of chemotherapy on gastric focus were evaluated as grade 1a and the liver metastasis completely disappeared. This combination therapy proved useful to treat advanced gastric cancer in this patient.

Tachykininergic slow depolarization of motoneurones evoked by descending fibres in the neonatal rat spinal cord

1. In the isolated spinal cord of the neonatal rat, repetitive electrical stimulation of the upper cervical region elicited a prolonged depolarization of lumbar motoneurones (L3-5) lasting 1-2 min, which was recorded extracellularly from ventral roots, or intracellularly. 2. This depolarizing response was markedly depressed by the excitatory amino acid receptor antagonists D-(-)-2-amino-5-phosphonovaleric acid (D-APV, 30 microM) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10 microM). The remaining response was further depressed by a 5-hydroxytryptamine (5-HT) receptor antagonist, ketanserin (3 microM). 3. In the presence of these antagonists, a small part of the depolarizing response of slow time course remained, and this response was partially blocked by the tachykinin NK1 receptor antagonists GR71251 (0.3-5 microM) and RP67580 (0.3-1 microM). In contrast, RP68651 (0.3-1 microM), the inactive enantiomer of RP67580, had no effect on the depolarizing response. 4. The slow depolarizing response in the presence of D-APV, CNQX and ketanserin was markedly potentiated by a peptidase inhibitor, thiorphan (1 microM). 5. This descending fibre-evoked slow depolarization became smaller after prolonged treatment (5-7 h) with 5,7-dihydroxytryptamine (10 microM), a neurotoxin for 5-HT neurones. Under such conditions, the effects of thiorphan and GR71251 on the slow depolarization were virtually absent. 6. Under the action of D-APV, CNQX and ketanserin, applications of tachykinins, substance P and neurokinin A produced depolarizing responses of lumbar motoneurones, and the responses were depressed by GR71251 and potentiated by thiorphan. 7. These results suggest that tachykinins contained in serotonergic fibres serve as neurotransmitters mediating the descending fibre-evoked slow excitatory postsynaptic potentials in motoneurones.

Comprehensive site-directed mutagenesis of L-2-halo acid dehalogenase to probe catalytic amino acid residues

L-2-Halo acid dehalogenase catalyzes the stereospecific hydrolytic dehalogenation of L-2-halo acids, with inversion of the C2-configuration. Seven L-2-halo acid dehalogenases from various bacterial strains are significantly similar to one another in their amino acid sequences (36-70% identity), and they are supposed to catalyze the reaction through the same mechanism. To identify catalytically important residues, we mutated all the 36 highly conserved charged and polar amino acid residues of L-2-halo acid dehalogenase from Pseudomonas sp. YL, which consists of 232 amino acid residues, by replacement of D by N, E by Q, R by K, and vice versa, S and T by A, Y and W by F, M by L, and H by N. We found that the replacement of D10, K151, S175, D180, R41, S118, T14, Y157, and N177 led to a significant loss in the enzyme activity or an increase in the Km value for the substrate, showing their involvement in the catalysis. The roles of these residues are discussed.

[Fatty acid metabolism in patients with idiopathic dilated cardiomyopathy: characteristics and prognostic implications]

The characteristics of myocardial fatty acid metabolism in patients with idiopathic dilated cardiomyopathy (DCM) were investigated by myocardial imaging with beta-methyl-p-[123I]iodophenyl-pentadecanoic acid (BMIPP) in 16 patients with DCM, 8 patients with hypertensive heart failure (HHF), and 11 normal subjects. Rest myocardial imaging with BMIPP and 201Tl was performed on another day. The index of myocardial BMIPP uptake, or uptake ratio, was calculated from the percentage uptakes of BMIPP and 201Tl. The index of inhomogeneity of intramyocardial isotope distribution was calculated as the coefficient of variation of BMIPP and 201Tl. The uptake ratio was significantly lower in DCM and HHF patients than in normal subjects (p < 0.01). Uptake ratio correlated well with fractional shortening (r = 0.76, p < 0.01), and left ventricular ejection fraction (r = 0.58, p < 0.01). Although uptake ratio was not different between DCM and HHF patients, defects in BMIPP imaging appeared more frequently in DCM (69%) than in HHF (38%) patients. Furthermore, the extent of the defect in BMIPP imaging in DCM patients was larger than that in 201Tl imaging (p < 0.05), but in HHF patients the extent of the defects in both methods was similar. The coefficient of variation of BMIPP in DCM patients was greater than those in HHF patients and in normal subjects, but those of 201Tl were not different between the three groups. The coefficient of variation of BMIPP in DCM patients correlated well with serum norepinephrine level (r = 0.57, p < 0.01) and atrial natriuretic peptide (r = 0.77, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Ischemic and hemorrhagic brain stem lesions mimicking diabetic ophthalmoplegia

Two patients with diabetes mellitus, one of them with an isolated third cranial nerve palsy and the other with an isolated sixth cranial nerve palsy, are presented. MRI investigations including diffusion-weighted MRI revealed a small ischemic brain stem lesion in the former and a small hemorrhagic brain stem lesion in the latter. In the former case wallerian degeneration of the nerve fascicle within the mesencephalon was also detected. These cases indicate that vascular accidents of the brain stem may masquerade as fascicular or infranuclear disturbance of the oculomotor or abducens nerve; therefore, it is important to include brain stem lesions into the differential diagnosis of isolated ophthalmoplegia. Thorough investigation by MRI including diffusion-weighted MRI is helpful for correct diagnosis.