Spectroscopic studies of bound cytochrome c and an iron-sulfur center in a purified reaction center complex from the green sulfur bacterium Chlorobium tepidum

Flash-induced optical kinetics at room temperature of cytochrome (Cyt) c 551 and an Fe-S center (CFA/CFB) bound to a purified reaction center (RC) complex from the green sulfur photosynthetic bacterium Chlorobium tepidum were studied. At 551 nm, the flash-induced absorbance change decayed with a t 1/2 of several hundred ms, and the decay was accelerated by 1-methoxy-5-methylphenazinium methyl sulfate (mPMS). In the blue region, the absorbance change was composed of mPMS-dependent (Cyt) and mPMS-independent component (CFA/CFB) which decayed with a t 1/2 of ∼400-650 ms. Decay of the latter was effectively accelerated by benzyl viologen (Em -360 mV) and methyl viologen (-440 mV), and less effectively by triquat (-540 mV). The difference spectrum of Cyt c had negative peaks at 551, ∼520 and ∼420 nm, with a positive rise at ∼440 to ∼500 nm. The difference spectrum of CFA/CFB resembled P430 of PSI, and had a broad negative peak at 430∼435 nm.

Interferon and cyclosporin A in the treatment of fulminant viral hepatitis

The prognosis of fulminant hepatitis due to non-A, non-B virus infection and acute reactivation of hepatitis B virus in HB carriers is generally poor, and the treatment of choice in Western countries is recognized as liver transplantation. In countries such as Japan where liver transplantation is not readily available, however, these intractable types of fulminant hepatitis have to be treated medically. Based on the assumption that persistent replication of causal viruses and enhanced host immune responses, especially cellular immunity, to eradicate the viruses are the key mechanism in progressive liver cell destruction and the poor prognosis, we attempted a combination treatment with interferon and cyclosporin A for these types of fulminant viral hepatitis. Subjects in the present study consisted of 1 patient with acute severe hepatitis without coma and 13 patients with coma (13 with fulminant hepatic failure) due to non-A, non-B virus and acute reactivation of hepatitis B virus. The patients were given interferon-beta, 300 x 10(4) U daily, and cyclosporin A, at an initial dose of 3 mg/kg, with tapering. Fourteen patients with coma received artificial liver support that we devised. The patient with acute severe hepatitis survived, showing histologically remarkable liver regeneration. Eight of the 14 patients with hepatic coma, all of whom were indications for liver transplantation according to the criteria of the King's College group, survived. Decreased transaminase level, increased liver volume, and histological liver regeneration were observed in all the survivors. The combination of interferon and cyclosporin A is worth attempting in fulminant hepatitis caused by non-A, non-B virus and acute reactivation of hepatitis B virus in HB carriers.

Sequential changes in the distribution of type I and III collagens in the infarct zone: immunohistochemical study of experimental myocardial infarction in the rat

AIM

Ventricular remodeling following acute myocardial infarction is an important factor in prognosis. The healing process, involving changes in type I and III collagens, is one of the major factors in remodelling. We therefore examined sequential changes in type I and III collagens after experimental myocardial infarction.

MATERIALS AND METHODS

Hearts were excised from 1 day to 10 weeks after permanent left coronary ligation in rats. Immunohistochemical staining with a polyclonal antibody to each collagen was performed by the avidin-biotin-peroxidase method.

RESULTS

Type I collagen initially appeared in the peripheral zone of the infarct from 3 days after ligation, the extent of staining gradually increasing until it reached a maximal level on days 21-28, after which the distribution remained unchanged. Type III collagen appeared in the peripheral zone of the infarct from 3 days after ligation; the extent of staining reached the maximal level after 11-28 days, after which a slight decrease in the distribution was observed, although the staining did not entirely disappear.

CONCLUSIONS

Type I collagen was a major factor in collagen matrix formation, especially in the relatively late phase. Type III collagen, however, contributed particularly to collagen matrix formation in the relatively early phase. This study improves current understanding of the time-dependent alterations in type I and III collagens involved in the healing process after coronary artery occlusion.

Specific binding of a synthetic peptide derived from an antibody complementarity determining region to phosphatidylserine

We have established a series of monoclonal antibodies that bind to phosphatidylserine (PS). One mAb, PS4A7, showed a strict specificity for PS and distinguished the stereospecific configuration of its serine moiety. We determined the amino acid sequences of the heavy and light chain variable regions of PS4A7, and examined the reactivity of the synthetic peptides corresponding to the complementarity determining region (CDR) of the mAb with phospholipids. We found that a 12-amino acid synthetic peptide corresponding to the third CDR of the heavy chain (amino acid residues 93-102, referred to as CDR3-H) bound specifically to PS. Although the affinity of the peptide to PS was markedly lower, the peptide was shown to bind to 1,2-diacyl-sn-glycero-3-phospho-L-serine (PS), but not to 1,2-diacyl-sn-glycero-3-phospho-D-serine, showing a similar specificity to that of PS4A7. The specific binding of the CDR3-H peptide to PS was confirmed by ELISA and TLC-immunostaining assay. The interaction between the CDR3-H peptide and water-soluble PS-derivatives was investigated by inhibition of the ELISA. PS effectively inhibited the binding and phosphoserine showed a weak but significant inhibition, but no appreciable inhibition was observed with serine. These observations suggest that the CDR3-H peptide plays a major role in the interaction of PS4A7 with the phosphoserine residue of the PS molecule.

[A case of primary intracranial malignant lymphoma showing a spontaneous regression]

An eighty-year-old woman, who had been admitted with disorientation and gait disturbance, was revealed to have multiple intracranial tumors in the right temporal lobe and cerebellar vermis on CT and MRI. Following intravenous injection of dexamethasone (8 mg/day) for three days, isosorbide (90ml/day) was given in order to decrease brain edema, and the tumors increased in size rapidly in the next four months. However, most of the lesions disappeared or became markedly small without any specific therapy three months after the exacerbation of the disease. The brain tumors recurred one year thereafter, and the pathological diagnosis of primary intracranial malignant lymphoma, diffuse large B-cell type was done by autopsy examination. This patient was considered to have shown a spontaneous regression during the clinical course, and the clinicopathological descriptions of the case are presumed to present characteristic features of primary, intracranial malignant lymphoma.

D2 receptors in the ventrolateral striatum are involved in feeding behavior in rats

To study the role of dopamine D1 and D2 receptors in the ventrolateral striatum in feeding behavior, a D1 receptor agonist (CY 208-243), a D1 receptor antagonist (SCH 23390), a D2 receptor agonist (quinpirole), and a D2 receptor antagonist [(-)-sulpiride] were perfused via a microdialysis probe into the ventrolateral striatum of rats fasted for 22 h. Then the rats were allowed to feed freely for 6 h. Sulpiride perfusion at a high concentration suppressed food and water intake significantly, whereas dopamine release and the levels of DOPAC and HVA were increased at all concentrations. In contrast, quinpirole perfusion at a high concentration increased food intake by 41%. Dopamine release and the levels of DOPAC and HVA were decreased at all concentrations. On the other hand, neither CY 208-243 nor SCH 23390 changed food intake or dopamine release, but both drugs decreased water intake. These results suggest that D2 receptors in the ventrolateral striatum have a more important role than D1 receptors in the feeding behavior of rats.

Nonselective cation channels coupled with tachykinin receptors in rat sensory neurons

1. Effects of substance P (SP) and other tachykinins on membrane currents were investigated using whole cell voltage clamp in cultured sensory neurons isolated from rat dorsal root ganglia. 2. SP (100 nM) evoked an inward current in two-thirds of the cells at negative potentials. In most of the cells that generated the inward current in response to SP, capsaicin also activated an inward current. The SP-evoked inward current was not observed in cells loaded with 2 mM guanosine 5'-O-(2-thiodiphosphate) (GDP beta S). 3. Neurokinin A (NKA) or neurokinin B (NKB) also activated an inward current. At 100 nM of each agonist, the order was NKB > NKA > SP with respect to activated current amplitude. 4. The tachykinin-activated current was reversed around +10 mV with a standard extracellular solution containing 140 mM NaCl. The reversal potential became more negative when extracellular NaCl was reduced by substituting with sucrose. The inward current was also activated in cells bathed in an extracellular solution containing Cs+, tetraethylammonium (TEA) or N-methyl-D-glucamine (NMDG) as a major cation instead of Na+. The order of permeability, determined from the reversal potential of the current, was Cs+ not equal to Na+ > TEA > NMDG. The amplitude of the inward current activated by NKB was increased when extracellular Na+ was replaced with Cs+, TEA or NMDG. 5. Permeability of Ca2+ was tested using an extracellular solution containing Ca2+ as the only cation (111.8 mM Ca2+ outside). Under this condition, NKB evoked an inward current that reversed around +30 mV. 6. The results suggest that SP and other tachykinins activate nonselective cation channels, which are also permeable to Ca2+, through receptors which are more responsive to NKB than to SP or NKA. The channel activation may serve as a mechanism underlying tachykinin-mediated excitatory neurotransmission in sensory neurons.

Molecular characterization of proteins in protein-body membrane that disappear most rapidly during transformation of protein bodies into vacuoles

During the post-germination growth of seeds, protein bodies fuse with one another and are converted to a central vacuole. To investigate this transition, protein-body membranes from dry seeds of pumpkin (Cucurbita sp.) were prepared and their protein components characterized. Five major proteins (designated MP23, MP27, MP28, MP32 and MP73) were detected in the protein-body membranes. A cDNA clone encoding both MP27 and MP32 has been isolated. The deduced precursor polypeptide was composed of a hydrophobic signal sequence, MP27 and MP32, in that order. A putative site of cleavage between MP27 and MP32 was located on the COOH-terminal side of asparagine 278, an indication that the post-translational cleavage may occur by the action of a vacuolar processing enzyme that converts proprotein precursors of seed proteins into the mature forms. Immunoelectron microscopic analysis showed that MP27 and MP32 were associated with protein-body membrane of dry pumpkin seeds. Among the five membrane proteins, MP27 and MP32 disappeared most rapidly during seedling growth. The degradation of MP27 and MP32 starts just after seed germination and proceeds in parallel with the transformation of the protein bodies into a vacuole.

[ATP as a neurotransmitter in the brain: its possibility based upon recent findings]

We discuss here possible neurotransmitter roles of extracellular ATP in the central nervous system. Important findings concerning the effects of ATP on central neurons have been made in the last few years. A fast neurotransmitter role of ATP in rat medial habenula reported by Edwards et al (1992) may be the best example. In rat cultured hippocampal neurons, we have found that ATP evokes postsynaptic currents, and increases the intracellular Ca2+ concentration. In addition, ATP also produces a "long-term potentiation like effect" in these cells. Receptors for ATP are generally divided into two classes: one class is coupled with ion channels and the other class is coupled with GTP-binding proteins. In cultured hippocampal neurons, the GTP-binding protein-coupled receptors are present and promote the inhibition of K+ channels. Although the channel-coupled receptors have not been identified in the hippocampal neurons, these channels have been found in nucleus solitarii and locus coeruleus. Several types of ATP receptors have been cloned very recently. These cloned receptors, combined with molecular biological techniques, will allow great progress in this field.

Cloning and expression of a bovine glutamate transporter

We have isolated a 3845 base-pair cDNA (BNGLUAS) encoding a bovine glutamate transporter (bovine GLAST) by screening a bovine retina cDNA library with an oligonucleotide probe corresponding to conserved regions of known glutamate transporters. The cDNA sequence predicted a protein of 542 amino acids and displayed 96% and 97% amino acid identity with the rat GLAST/GluT-1 and human GLAST, respectively. Expression of the bovine GLAST in Xenopus oocytes revealed Na(+)-dependent [14C]L-glutamate uptake and electrogenic glutamate uptake.

Inhibition by suramin and reactive blue 2 of GABA and glutamate receptor channels in rat hippocampal neurons

Effects of suramin and reactive blue 2 (RB2), compounds known as antagonists at P2-purinoceptors, on ionic currents mediated through GABA and glutamate receptor channels were investigated in rat hippocampal neurons. Under whole-cell voltage-clamp, suramin (30 to 300 microM) and RB2 (10 to 100 microM) inhibited a current activated by 10 microM GABA in a concentration-dependent manner. Suramin (100 and 300 microM) and RB2 (10 and 30 microM) also inhibited an inward current activated by kainic acid (100 microM), an agonist at non-NMDA type glutamate receptor channels, and an inward current activated by N-methyl-D-aspartate (NMDA; 100 microM), an agonist at NMDA type glutamate receptor channels. The inhibition by suramin or RB2 did not exhibit voltage-dependence between -30 and -90 mV in the case of the GABA- or the kainate-evoked current. In contrast, the inhibition by these compounds of the NMDA-evoked current exhibited voltage-dependence and was enhanced by hyperpolarization. When the concentration of agonists was increased by 5- or 10-fold, the magnitude of the inhibition by suramin of the kainate-evoked current and the magnitude of the inhibition by RB2 of the NMDA-evoked current were attenuated. alpha,beta-Methylene ATP (100 microM) did not affect the GABA-, kainate- or NMDA-activated current. The results suggest that suramin and RB2 inhibit GABA receptor channels and glutamate receptor channels. The blockade of these channels must be taken into account when these compounds are used as pharmacological tools to examine an involvement of P2-purinoceptors, especially in preparations where GABAergic or glutamatergic neurotransmission is expected.

Ataxia with isolated vitamin E deficiency is caused by mutations in the alpha-tocopherol transfer protein

Ataxia with isolated vitamin E deficiency (AVED) is an autosomal recessive neurodegenerative disease which maps to chromosome 8q13. AVED patients have an impaired ability to incorporate alpha-tocopherol into lipoproteins secreted by the liver, a function putatively attributable to the alpha-tocopherol transfer protein (alpha-TTP). Here we report the identification of three frame-shift mutations in the alpha TTP gene. A 744delA mutation accounts for 68% of the mutant alleles in the 17 families analysed and appears to have spread in North Africa and Italy. This mutation correlates with a severe phenotype but alters only the C-terminal tenth of the protein. Two other mutations were found in single families. The finding of alpha TTP gene mutations in AVED patients substantiates the therapeutic role of vitamin E as a protective agent against neurological damage in this disease.

Chinese hamster ovary cells expressing a novel type of acetylated low density lipoprotein receptor. Isolation and characterization

Macrophage scavenger receptors mediate the recognition of a wide range of negatively charged macromolecules including acetylated low density lipoproteins (AcLDL). Chinese hamster ovary (CHO) cells were cultured in the presence of increasing concentrations of simvastatin, a cholesterol biosynthesis inhibitor, and AcLDL as the sole source of exogenous lipoproteins. The cells surviving under these conditions specifically bound 125I-labeled AcLDL with high affinity and degraded them via an endocytic pathway. Unexpectedly, the association and degradation of 125I-labeled AcLDL by these CHO cells were not inhibited by dextran sulfate, fucoidan, and polyinosinic acid, competitors of macrophage scavenger receptors, but were completely inhibited by maleylated bovine serum albumin. Furthermore, these cells effectively took up negatively charged liposomes containing acidic phospholipids such as phosphatidylserine and phosphatidic acid, whereas CHO cells expressing macrophage scavenger receptors did not. AcLDL and negatively charged liposomes were cross-competed with each other. Northern blot analysis using the cDNA for the macrophage scavenger receptor revealed that these CHO cells did not express this receptor. From these observations, we conclude that the isolated CHO cells express a novel type of AcLDL receptor, which is distinct from macrophage scavenger receptors with respect to ligand specificity and competitor sensitivity.

Lipoxygenase-catalyzed oxygenation of arachidonylethanolamide, a cannabinoid receptor agonist

Various purified lipoxygenases were incubated with [14C]arachidonylethanolamide which is an endogenous ligand for cannabinoid receptors. When radioactive products were analyzed by thin-layer chromatography, porcine leukocyte 12-lipoxygenase and rabbit reticulocyte and soybean 15-lipoxygenases produced polar compounds at about the same reaction rates as that of oxygenation of free arachidonic acid. In contrast, the reaction of human platelet 12-lipoxygenase proceeded at a much lower rate, and porcine leukocyte 5-lipoxygenase was totally inactive. The result indicated that the lipoxygenases, which had been shown previously to be capable of oxygenating esterified polyunsaturated fatty acids, were also active with the arachidonylethanolamide. High-performance liquid chromatography, ultraviolet and mass spectrometry and nuclear magnetic resonance spectroscopy identified the major product by leukocyte 12-lipoxygenase as 12-hydroperoxy-5,8,10,14-eicosatetraenoylethanolamide and that by 15-lipoxygenases as 15-hydroperoxy-5,8,11,13-eicosatetraenoylethanolamide. The 15-hydroxy derivative inhibited electrically-evoked contraction of mouse vas deferens with an IC50 of 0.63 microM as well as arachidonylethanolamide (0.17 microM), but the 12-hydroxy derivative was much less effective.

Isolation and in vitro phosphorylation of sensory transduction components controlling anaerobic induction of light harvesting and reaction center gene expression in Rhodobacter capsulatus

Anaerobic induction of light harvesting and reaction center gene expression involves two transacting factors termed RegA and RegB. Sequence and mutational analysis has indicated that RegA and RegB constitute cognate components of a prokaryotic sensory transduction cascade with RegB comprising a membrane-spanning sensor kinase and RegA a cytosolic response regulator. In this study we have purified RegA, as well as a truncated portion of RegB (RegB') and undertaken an in vitro analysis of autophosphorylation and phosphotransfer activities. Incubation of RegB' with [gamma-32P]ATP and MgCl2 resulted in phosphorylation of RegB' (RegB' approximately P) over a 20-min incubation period. Incubation of RegB' approximately P with RegA resulted in rapid transfer of the phosphate from RegB' to RegA. In analogy to other characterized prokaryotic sensory transduction components, mutational and chemical stability studies also indicate that RegB' is autophosphorylated at a conserved histidine and that RegA accepts the phosphate from RegB at a conserved aspartate.

Selective and competitive antagonism by suramin of ATP-stimulated catecholamine-secretion from PC12 phaeochromocytoma cells

1. Suramin, a putative P2-antagonist, (10 to 300 microM) inhibited the adenosine 5'-triphosphate (ATP)-stimulated secretion of [3H]-noradrenaline or endogenous dopamine from phaeochromocytoma PC12 cells in a concentration-dependent manner. Suramin (300 microM) did not affect the dopamine-secretion stimulated by high K+ or nicotine. 2. Suramin shifted the concentration-response curve for ATP to the right. The antagonism was competitive with a pA2 value of 4.52. 3. ATP also stimulated an increase in intracellular Ca2+ concentration as determined by fura-2 methods. Suramin antagonized this effect over the same concentration range that antagonized the ATP-stimulated catecholamine secretion. 4. These results suggest that suramin can be used as a selective and competitive antagonist of ATP in experiments concerning mechanisms of catecholamine-secretion.

Accentuation by pertussis toxin of the 5-hydroxytryptamine-induced potentiation of ATP-evoked responses in rat pheochromocytoma cells

We previously demonstrated that 5-hydroxytryptamine (5-HT) enhances the cationic current activated by extracellular ATP in rat pheochromocytoma PC12 cells. We report here that pertussis toxin (PTX) modulates this 5-HT-dependent enhancement in these cells. 5-HT potentiated ATP-evoked intracellular Ca2+ concentration ([Ca]i) rise and dopamine release over a concentration range from 1 to 100 microM. When cells were pre-treated with PTX, this potentiation was accentuated. Pretreatment with PTX also accentuated the 5-HT-dependent enhancement of the ATP-activated current. These results suggest that the enhancement by 5-HT of the ATP-evoked responses is negatively regulated by a mechanism mediated through PTX-sensitive GTP-binding protein.

Effects of cyclosporine and tacrolimus (FK 506) on acute pancreatitis in mice

OBJECTIVE

To use mice to examine the effects of cyclosporine and tacrolimus (FK 506) on two forms of acute pancreatitis often seen after clinical organ transplantation.

METHODS AND DESIGN

In the first experiment, male CD-1 mice received cyclosporine (10 mg/kg), tacrolimus (0.32 mg/kg), or saline solution (control) subcutaneously once a day for 10 days. On the 11th day, acute edematous pancreatitis was induced by ceruletide (cerulein). In the second experiment, female ICR mice were fed with a choline-deficient, ethionine-supplemented (CDE) diet for 72 hours to induce necrotizing pancreatitis. After 30 hours on the CDE diet, the mice received cyclosporine (10 mg/kg), tacrolimus (0.32 mg/kg), or saline solution (control) subcutaneously twice daily for 3 days.

RESULTS

The pancreatic dry-to-wet weight ratios after ceruletide injections significantly decreased in mice treated with cyclosporine but did not with tacrolimus. Cyclosporine also significantly increased serum amylase levels, but tacrolimus did not. Cyclosporine or tacrolimus alone did not produce pancreatitis. In the CDE diet groups there was a significant difference in survival among the cyclosporine-treated, the tacrolimus-treated, and the control groups.

CONCLUSIONS

Cyclosporine or tacrolimus given alone does not induce acute pancreatitis. In contrast, cyclosporine can adversely affect the course of acute edematous pancreatitis, and both immunosuppressants may worsen the survival of mice with acute hemorrhagic necrotizing pancreatitis. This study also demonstrated that the deteriorating effect of tacrolimus is less potent than that of cyclosporine.

Spontaneous rupture of the iliac vein: report of a case

We report a rare case of a spontaneous rupture of the iliac vein which was then surgically treated with good results. A 66-year-old woman was admitted complaining of leg swelling and lower abdominal pain. On the 3rd day after admission, an operation was performed because of a gradually increasing hematoma in the retroperitoneal space. Laparotomy revealed a 17 mm longitudinal tear on the anterior surface of the left external iliac vein with a thrombus inside the lumen. Most of the previously reported 14 cases of this nature have required emergency operations.

High-performance liquid chromatography and fluorometric detection of arachidonylethanolamide (anandamide) and its analogues, derivatized with 4-(N-chloroformylmethyl-N-methyl)amino-7-N,N-dimethylaminosulp honyl-2,1 ,3- benzoxadiazole (DBD-COCl)

The endogeneous ligand for the cannabinoid receptor, arachidonylethanolamide (anandamide) and its analogues, oleinylethanolamide, palmitylethanolamide and eicosapentaenoylethanolamide, were derivatized with a fluorogenic reagent, 4-(N-chloroformylmethyl-N-methyl)amino-7-N,N-dimethylaminsulpho ny1-2,1,3- benzoxadiazole (DBD-COCl). They were separated on a reversed phase HPLC with a mobile phase of acetonitrile:water. The fluorometric detection of the derivatives was made at 560 nm with excitation at 450 nm and the detection limits for anandamide was 20 fmol on column. The structures of DBD-CO-ethanolamides were confirmed by liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS).

Effect of oral multiple-dose administration of anti-inflammatory flurbiprofen chimera drug on gastric lesion, other toxicities and disposition kinetics

Flurbiprofen (FP) was esterified with a histamine H2-antagonist, PPA (N-[3-(3-(1-piperidinylmethyl)phenoxy)-propyl]-2-(2- hydroxyethylthio)acetamide), to yield a chimera drug, FP-PPA, and its protective effect toward gastric lesions, other toxicities and the disposition kinetics were investigated, as compared to those of FP, in multiple oral administration to rats for 2 weeks. FP-PPA scarcely formed any disorder of the gastric mucosa following multiple oral administration. The body weight changes and hematological and serum biochemical parameters were found to be similar to those in the control group. Some drug metabolizing enzyme activities tested were the same as those of the control group. Further, the pharmacokinetic parameters were found to be the same after both single and multiple oral administration. On the other hand, in the FP treated group, the inhibition of body weight increase and changes in serum biochemical and hematological parameters were observed due to malabsorption. The absorption rate constant was increased significantly after multiple administration as compared to that of single administration. It is suggested that these changes in the absorption process of FP are due to variations in gastrointestinal permeability derived from gastrointestinal damage. The results obtained here indicate clearly that the chimera drug FP-PPA scarcely forms any disorder of the gastric mucosa, even after multiple oral administration, and is thus a potential candidate for oral use.