Cysteine 10 is a key residue in amyloidogenesis of human transthyretin Val30Met

Type I familial amyloidotic polyneuropathy (FAP), a systemic amyloidosis, is characterized by aggregation of variant transthyretin (TTR Val30Met) into stable, insoluble fibrils. This aggregation is caused by genetic and environmental factors. Genetic factors have been studied extensively. However, little is known about environmental or physiological factors involved in the disease process, and their identification may be important for development of effective treatment. X-ray crystallography of normal and amyloidogenic human TTR Val30Met in type I FAP showed that the -SH side chain of cysteine at position 10 (Cys10) forms a hydrogen bond with Gly57 in normal TTR but not in TTR Val30Met. This result suggests a crucial role for the free Cys10 residue and possible involvement of physiological factors affecting Cys residue reactivity in TTR amyloidogenesis. To analyze amyloidogenesis in vivo, our group generated murine FAP models by transgenic technology, with human TTR Val30Met. The three lines of transgenic mice expressed amyloidogenic mutant TTR (Cys10/Met30), wild-type TTR (Cys10/Val30), and artificial Cys-free mutant TTR (Ser10/Met30). Histochemical investigation showed deposition of amyloid derived from human TTR only in amyloidogenic mutant TTR (Cys10/Met30) mice. Thus, the -SH residue in Cys10 plays a crucial role in TTR Val30Met amyloidogenesis in vivo. These data suggest the possibility of innovative treatment via physiological factors modulating Cys10 residue reactivity.

The shape parameter of liposomes and DNA-lipid complexes determined by viscometry utilizing small sample volumes

A minicapillary viscometer utilizing <0.5 ml of sample at a volume fraction of <0.1% is described. The calculated a/b of DPPC/DPPG multilamellar liposome was 1.14 as prolate ellipsoids and a/b of dioleoylpropyltrimethyl ammonium methylsulfate-DNA complex at a charge ratio of 4:1 (+/-) was 3.7 as prolate ellipsoids or 4.9 as oblate ellipsoids. The deviation of shape from perfect sphere is thus expressed quantitatively in more than two significant figures. In these measurement, the necessary amount of DNA is <0.5 mg.

Delayed rupture of traumatic intracranial pseudoaneurysm in a child following gunshot wound to the head

BACKGROUND AND OBJECTIVES

Traumatic intracranial aneurysms (TICAs) are highly unstable lesions that may rupture within minutes after formation or remain quiescent for several weeks and manifest with delayed hemorrhage and neurologic deterioration. Mortality following a rupture may be 30% to 40%. Among all cerebral aneurysms, the incidence of TICAs is less than 1%; 20% to 30% of TICAs occur in children.

METHODS AND MATERIALS

A child with a low-caliber craniocerebral gunshot wound deteriorated neurologically 12 days after the initial injury and emergency evacuation of an intracranial hematoma. A new massive left frontal hematoma was discovered, caused by the rupture of an unsuspected left pericallosal artery pseudoaneurysm. The new hematoma was evacuated, and the aneurysm was trapped using microsurgical techniques.

RESULTS AND/OR CONCLUSIONS

A high index of suspicion should be maintained for delayed pseudoaneurysm genesis and rupture. A cerebral arteriogram should be obtained when significant subarachnoid hemorrhage or intraparenchymal hematomas are present, when missiles traverse major arteries, or when the pterional or cranioorbitofacial regions are violated. Treatment should be prompt.

Effects of phospholipid unsaturation on the membrane/water interface: a molecular simulation study

Molecular dynamics (MD) simulations of fully hydrated bilayers in the liquid-crystalline state made of 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) or 1-palmitoyl-2-elaidoyl-phosphatidylcholine (PEPC) were carried out to investigate the effect of the incorporation of a double bond in the phosphatidylcholine (PC) beta-chain (cis or trans) on the membrane/water interface. The bilayers reached thermal equilibrium after 3 and 1 ns of MD simulations, respectively, and productive runs were carried out for 3 ns for each bilayer. As reference systems, the 1,2-dimyristoyl-phosphatidylcholine (DMPC) bilayer (M. Pasenkiewicz-Gierula, Y. Takaoka, H. Miyagawa, K. Kitamura, and A. Kusumi, 1999, Biophys. J. 76:1228-1240) and DMPC-cholesterol (Chol) bilayer containing 22 mol % Chol (M. Pasenkiewicz-Gierula, T. Róg, K. Kitamura, A. and Kusumi, 2000, Biophys. J. 78:1376-1389) were used. The study shows that at the interface of POPC, PEPC, and DMPC-Chol bilayers, average numbers of PC-water and PC-PC interactions are similar and, respectively, greater and smaller than in the DMPC bilayer. The average area/PC in mono-unsaturated bilayers is approximately 4 A(2) larger than in the DMPC bilayer; nevertheless, a strong correlation was found between a single molecular area (SMA) of a PC and the number of interactions this PC makes; i.e., PCs (either saturated or unsaturated) with the same SMA form similar numbers of intermolecular links. The numbers and corresponding SMAs are distributed about averages pertinent to each bilayer. No significant difference between cis and trans bonds was found.

Fast lipid disorientation at the onset of membrane fusion revealed by molecular dynamics simulations

Membrane fusion is a key event in vesicular trafficking in every cell, and many fusion-related proteins have been identified. However, how the actual fusion event occurs has not been elucidated. By using molecular dynamics simulations we found that when even a small region of two membranes is closely apposed such that only a limited number of water molecules remain in the apposed area (e.g., by a fusogenic protein and thermal membrane fluctuations), dramatic lipid disorientation results within 100 ps-2 ns, which might initiate membrane fusion. Up to 12% of phospholipid molecules in the apposing layers had their alkyl chains outside the hydrophobic region, lying almost parallel to the membrane surface or protruding out of the bilayer by 2 ns after two membranes were closely apposed.

Molecular dynamics generation of nonarbitrary membrane models reveals lipid orientational correlations

This report addresses the following problems associated with the generation of computer models of phospholipid bilayer membranes using molecular dynamics simulations: arbitrary initial structures and short equilibration periods, an Ewald-induced strong coupling of phospholipids, uncertainty regarding which value should be used for surface tension to alleviate the problem of the small size of the membrane, and simultaneous realization of both order parameters and the surface area. We generated a computer model of the liquid-crystalline L-alpha-dimyristoylphosphatidylcholine (DMPC) bilayer, starting from a configuration based on a crystal structure (rather than from an arbitrary structure). To break the crystalline structure, a 20-ps high-temperature pulse of 510 K (but not 450 or 480 K) was effective. The system finally obtained is an all-atom model, with Ewald summation to evaluate Coulombic interactions and a constant surface tension of 35 dynes/cm/water-membrane interface, equilibrated for 12 ns (over 50 ns total calculation time), which reproduces all of the experimentally observed parameters examined in this work. Furthermore, this model shows the presence of significant orientational correlations between neighboring alkyl chains and between shoulder vectors (which show the orientations of the lipids about their long axes) of neighboring DMPCs.

Effect of selective IL-6 inhibitor Am-80 on experimental autoimmune encephalomyelitis in DA rats

AIM

To observe the role of interleukin (IL)-6 in the development of experimental autoimmune encephalomyelitis (EAE).

METHODS

DA rats were immunized by injecting bovine myelin basic protein (MBP). mRNA of cytokines, such as IL-6, IL-10, TNF-alpha, TGF-beta 1, IFN-gamma, and iNOS, were detected by RT-PCR. MBP was injected into ear to induce delayed type cutaneous hypersensitivity response (DTH). Histological studies were performed on the spinal cord with HE staining. Nitric oxide (NO) production from cultured murine macrophage clones was stimulated with LPS plus IFN-gamma.

RESULTS

DA rats developed EAE disease with a peak of severity on d 13 and d 14. Am-80 (1.0, 3.0 mg/kg), a selective IL-6 inhibitor, inhibited the symptoms in terms of deterioration as observed by the clinical score, body weight and histological findings, in a dose-related manner. A high dose of Am-80 (3.0 mg/kg for 12 d) did not completely inhibit the disease, but delayed the symptoms and enhanced the delayed response. By prolonging the duration of treatment (18 d), Am-80 inhibited the onset of EAE during administration, but the symptoms of EAE appeared after the administration was stopped. Am-80 administerd for 12 d inhibited the DTH response on d 11 but not on d 22. RT-PCR studies demonstrated a strong expression of IFN-gamma, IL-6, IL-10, TGF-beta 1, TNF-alpha, and iNOS mRNA in spinal cord 13 d after immunization. However IFN-gamma, IL-10, TNF-alpha, and iNOS mRNA expression (on d 13) was suppressed by Am-80, except in the case of IL-6, hence the effect of Am-80 on the expression of IL-6 mRNA was examined in additional experiments. After Am-80 was administered for 12 d or 18 d, the expression of IL-6 mRNA was inhibited on d 12 or d 18, but increased on d 13 or d 19, respectively.

CONCLUSION

These findings suggest that inhibition of EAE by Am-80 is initiated by inhibition of IL-6 production.

Antibody-catalyzed removal of the p-nitrobenzyl ester protecting group: the molecular basis of broad substrate specificity

Antibody catalysts for the removal of the p-nitrobenzyl ester protecting group have been generated to accommodate a broad range of substrates. Antibody 7B9, which was elicited against p-nitrobenzyl phosphonate 1, catalyzed the hydrolyses of p-nitrobenzyl monoesters of nonsubstituted, and beta- and gamma-substituted glutaric acids with almost identical Km and kcat values. In addition, 7B9 displayed substrate tolerance towards the a-substituents and accepted the p-nitrobenzyl esters of Leu, Norleu, and Phe. To define the molecular basis of the broad substrate tolerance, we have cloned and sequenced the antibody and constructed a model of the active-site-hapten complex. The model showed a relatively shallow pocket of the antigen-combining site that accommodates the p-nitrobenzyl moiety, and this is consistent with the observed substrate specificity. Thus, in the antibody-catalyzed reaction, the alpha-, beta-, and gamma-substituents of the substrates should be outside the combining site and ignored by the antibody recognition. A structural comparison of 7B9 with antibody D2.3, elicited against the structurally similar haptenic phosphonate, suggests the significance of the linker moiety in hapten design, which endows antibody catalysts with broad substrate specificity. These investigations provide new strategies for the generation of catalytic antibodies that accept a broad range of substrates for practical applications in organic synthetic chemistry.

Molecular dynamics simulations of bovine cathepsin B and its complex with CA074

To promote our better understanding of the dynamic stability of the bovine cathepsin B structure, which is characterized by an extra disulfide bond at Cys148-Cys252 from the other species, and of the binding stability of CA074 (a cathepsin B-specific inhibitor), molecular dynamics (MD) simulations were performed for the enzyme and its CA074 complex, assuming a system in aqueous solution at 300 K. The MD simulation covering 400 ps indicated that the existence of a Cys148-Cys252 disulfide bond increases the conformational flexibility of the occluding loop, although the conformational stability of the overall structure is little affected. The structural characteristics of the complex elucidated by X-ray analysis were suggested to be also intrinsic and stable in the dynamic state; the hydrogen bonding/electrostatic interactions between the main and side chains of CA074 and the Sn and Sn' subsites of the enzyme were maintained throughout the MD simulation. Furthermore, the simulation made clear that the binding of CA074 significantly restricted the conformational flexibility of the substrate binding region, especially the occluding loop, of cathepsin B. Statistical analyses during the simulation suggest that the selectivity of CA074 for cathepsin B stems from the tight P1'-S1' and P2'-S2' interactions, assisted in particular by double hydrogen bonds between the carboxyl two oxygens of the CA074 C-terminus and the imidazole NH groups of His110 and His111 residues.

Interleukin-1beta induces interleukin-6 production through the production of prostaglandin E(2) in human osteoblasts, MG-63 cells

This study was conducted to investigate the mechanism of interleukin-1beta (IL-1beta)-induced IL-6 production in human osteoblasts (MG-63 cells). Stimulation with IL-1beta resulted in the production of IL-6 and prostaglandin E(2) (PGE(2)). IL-6 production gradually increased and peaked 96 h after stimulation. IL-6 mRNA was detected between 4 and 72 h after IL-1beta stimulation. The patterns of PGE(2) production and the expression of cyclooxygenase-2 (COX-2) mRNA were biphasic after stimulation. Actinomycin D, cycloheximide, indomethacin, and NS-398 (COX-2 inhibitor) suppressed the production of IL-6 and PGE(2). Anti-PGE(2) antibody markedly reduced the production of IL-6. In addition, stimulation with 17-phenyl-PGE(2), a PGE receptor-1 (EP-1 receptor) agonist, led to the expression of IL-6 mRNA after pretreatment with IL-1beta. These findings indicate that IL-1beta-induced IL-6 production in MG-63 cells involves the following sequence of steps: IL-1beta-induced COX-2 activation, PGE(2) production, and EP-1 receptor signaling prior to IL-6 production.

The effect of mesoporphyrin on the production of cytokines by inflammatory cells in vitro

This study was conducted to investigate a mechanism of the anti-inflammatory action of mesoporphyrin, especially the effect on the production of cytokines by some cultured inflammatory cells. Mesoporphyrin had no effect on lipopolysaccharide-induced tumor necrosis factor-alpha production by RAW 264.7 cells (murine macrophage-like cells). Mesoporphyrin inhibited interferon-gamma production by 1E10.H2 cells (murine T helper-1 cells), but not interleukin-4 production by D10.G4.1 cells (murine T helper-2 cells). Mesoporphyrin inhibited interleukin-6 production by human osteoblast-like MG-63 cells. This inhibition of interleukin-6 production is closely related to the suppression of prostaglandin E2 generation by interfering cyclooxygenase 1 and 2 enzyme activities. These data suggest that the inhibition of cytokine production is one of the anti-inflammatory mechanisms of mesoporphyrin.

Charge pairing of headgroups in phosphatidylcholine membranes: A molecular dynamics simulation study

Molecular dynamics simulation of the hydrated dimyristoylphosphatidylcholine (DMPC) bilayer membrane in the liquid-crystalline phase was carried out for 5 ns to study the interaction among DMPC headgroups in the membrane/water interface region. The phosphatidylcholine headgroup contains a positively charged choline group and negatively charged phosphate and carbonyl groups, although it is a neutral molecule as a whole. Our previous study (Pasenkiewicz-Gierula, M., Y. Takaoka, H. Miyagawa, K. Kitamura, and A. Kusumi. 1997. J. Phys. Chem. 101:3677-3691) showed the formation of water cross-bridges between negatively charged groups in which a water molecule is simultaneously hydrogen bonded to two DMPC molecules. Water bridges link 76% of DMPC molecules in the membrane. In the present study we show that relatively stable charge associations (charge pairs) are formed between the positively and negatively charged groups of two DMPC molecules. Charge pairs link 93% of DMPC molecules in the membrane. Water bridges and charge pairs together form an extended network of interactions among DMPC headgroups linking 98% of all membrane phospholipids. The average lifetimes of DMPC-DMPC associations via charge pairs, water bridges and both, are at least 730, 1400, and over 1500 ps, respectively. However, these associations are dynamic states and they break and re-form several times during their lifetime.

Effect of Am-80, a synthetic derivative of retinoid, on experimental arthritis in mice

Am-80 is a newly snythesized retinoid with the structure of one aromatic amide among retinobenzoic acids. It exhibits specific biological activities of retinoic acid such as the activation of cellular differentiation and proliferation. We investigated the effect of Am-80 on collagen-induced arthritis (CIA) in mice and the immunopharmacological action on the production of several cytokines in the in vitro and in vivo models. Am-80, at doses of 0.3, 1 and 3 mg/kg, significantly inhibited the severity and development of the arthritis index, progression of foot pad swelling, bone damage and histopathological alterations. Am-80 also inhibited the production of anti-type II collagen (CII) IgG antibody, but did not affect the delayed-type hypersensitivity (DTH) response in arthritic mice. To determine the inhibitory mechanism of Am-80, we studied the effect of Am-80 on the production of cytokines. Am-80 did not affect the production of IFN-gamma by Th1 cells (1E10.H2 cells) and IL-4 by Th2 cells (D10.G4.1 cells), respectively. Am-80 selectively inhibited bacterial lipopolysaccharide (LPS)-induced IL-6, but not TNF-alpha and IL-1beta, production in mice. Moreover Am-80 inhibited IL-1beta induced IL-6 production and IL-6 mRNA expression in human osteoblast-like cells (MG-63). The inhibition of IL-6 production by Am-80 was due to downregulation of the pretranscription or the transcription of IL-6 in MG 63 cells. These findings suggest that the inhibitory effect of Am-80 on CIA is partially by modulating the production of the proinflammatory cytokine, IL-6.

The clinical efficacy of low-dose step-up follicle stimulating hormone administration for treatment of unexplained infertility

The present study was designed to compare the clinical efficacy of low-dose step-up follicle stimulating hormone (FSH) administration with conventional FSH protocol (FSH was injected daily starting with a dose of 150 IU), both combined with intrauterine insemination (IUI), for the treatment of unexplained infertility. A total of 97 unexplained infertility couples was randomly assigned to one or other of the two treatment groups, either conventional FSH with IUI (48 patients) or low-dose step-up FSH with IUI (49 patients), and only the first treatment cycle was evaluated in each protocol. The difference in pregnancy rates per cycle was not statistically significant between the low-dose FSH group and the conventional group [seven of 49 (14.3%) and seven of 48 (14.6%) respectively]. A significant reduction in the incidence of ovarian hyperstimulation syndrome (OHSS) was observed in the low-dose group (8.3% versus 27.1%, P < 0.05). The incidence of moderate OHSS requiring hospitalization was reduced significantly in the low-dose group (low-dose 0% versus conventional 16.7%, P < 0.01). However, the low-dose protocol did not completely prevent multiple pregnancies. Our results suggest that the low-dose step-up FSH treatment appeared to be useful for the treatment of unexplained infertility because of the high pregnancy rates and the significant decrease in the incidence of OHSS.

Requirement of sperm-oocyte plasma membrane fusion for establishment of the plasma membrane block to polyspermy in human pronuclear oocytes

We investigated whether the incorporation of the sperm membrane into the oolemma contributes to the human plasma membrane block to polyspermy. We used zona pellucida-free oocytes fertilized by intracytoplasmic sperm injection (ICSI) or activated by parthenogenetic activation. Only two of the 35 pronuclear oocytes fertilized by spermatozoa (control) demonstrated one single penetrating spermatozoa. In contrast, the majority of ICSI and parthenogenetically activated pronuclear oocytes were penetrated with an average of three spermatozoa per oocyte. The number of fused and binding spermatozoa of ICSI and parthenogenetically activated oocytes were significantly higher than in control oocytes (3.5+/-0.6 and 4.3+/-0.6 for ICSI; 3.0+/-0.3 and 3.8+/-0.4 for activated and 0.2+/-0.1 and 0.6+/-0.2 for controls, respectively, P < 0.01). Furthermore, the cortical granules were released from the cortex of ICSI and calcium ionophore-puromycin-activated pronuclear oocytes to the same extent as that of pronuclear oocytes fertilized by spermatozoa. These results suggest that the establishment of the plasma membrane block to sperm penetration in the human oocyte may require a fusion process between sperm and oocyte plasma membranes.

Expression of a foreign gene in Chlamydomonas reinhardtii chloroplast

Chimeric genes for expression of a foreign gene in the Chlamydomonas reinhardtii chloroplast were constructed. These chimeric genes are composed of the promoter from chloroplast genes, rbcL, psbA, and atpA, 5'- and 3'-untranslated regions, and the Escherichia coli beta-glucuronidase (GUS) structural gene (uidA) as a foreign gene. Three types of chloroplast transformants (RG, PG, and AG), which contained the rbcL-uidA, psbA-uidA, and atpA-uidA chimeric genes integrated in the chloroplast genome, were generated by particle bombardment. The AG transformant grown under photoautotrophic conditions showed the highest GUS activity (130 nmol/min/mg protein) so far reported in C. reinhardtii, and the accumulated GUS protein accounted for 0.08% of the total soluble proteins. GUS activity in RG was 12% of that in AG, and no activity was detected in PG. We also measured the GUS activity from transformants grown under heterotrophic conditions, but the culture conditions made little difference in activity levels. The difference in the amount of accumulated GUS protein in the transformants was paralleled by the difference in the level of transcripts, and the pattern of gene expression was not the same as that of the endogenous genes in the chloroplast.

Cloning and expression of a cDNA encoding a new neurocalcin isoform (neurocalcin alpha) from bovine brain

Neurocalcin (NC), a neuron-specific EF-hand Ca2+-binding protein, purified from bovine brain [Terasawa, Nakano, Kobayashi and Hidaka (1992) J. Biol. Chem. 267, 19596-19599] contains multiple isoforms. We previously cloned NCdelta from bovine brain and showed high expression in neuronal tissues [Okazaki, Watanabe, Ando, Hagiwara, Terasawa and Hidaka (1992) Biochem. Biophys. Res. Commun. 185, 147-153]. We report here the molecular cloning and expression of a cDNA encoding bovine brain NCalpha. The translated bovine protein is 191 amino acids long and shares 69.1% of its amino acid sequence with NCdelta. Recombinant NCalpha migrates as a single 23 kDa band and exhibits a Ca2+-dependent mobility shift on SDS/PAGE. Analysis of fluorescence emission spectra showed the Ca2+-induced peak at 337 nm. Interestingly, the mobility shift and the fluorescence intensity at 337 nm were larger for NCalpha than for NCdelta. In Ca2+-overlay experiments, however, the apparent affinity of NCalpha for 45Ca2+ was similar to that of NCdelta. Immunohistochemical analysis revealed NCalpha expression in the granular layer of the rat cerebellar cortex whereas NCdelta was found in the Purkinje cell layer. In the rat olfactory bulb, NCalpha was located in external tufted cells, and NCdelta was found in the periglomerular cells. These data demonstrate that NC isoforms differ in their tissue distribution and conformational changes induced by Ca2+ binding. Thus differential regulation of the two NC isoforms may be involved in control of neuron function.

Cyclosporin A and FK-506 inhibit development of superantigen-potentiated collagen-induced arthritis in mice

1. Staphylococcal enterotoxine B (SEB; superantigen) accelerated the onset of arthritis in mice preimmunized with type II collagen (SEB-potentiated collagen-induced arthritis). Cyclosporin A and FK-506 inhibited the induction and development of clinical signs and histopathological changes of SEB-potentiated collagen-induced arthritis in mice. 2. Simultaneously, both cyclosporin A and FK-506 inhibited the development of humoral and cellular immunity to type II collagen. 3. The expression of IL-2 receptor (CD25) by SEB on splenocyte T cells from collagen-preimmunized mice was inhibited by both agents in ex vivo experimentation.

Molecular cloning of the cDNA encoding A + U-rich element RNA binding factor

Using the differential display method, a new cDNA clone, termed laAUF1, encoding the human A + U-rich RNA-binding motif was isolated and sequenced. Analysis of the protein sequence of laAUF1 indicates 73% homology between the deduced polypeptide sequences of laAUF1 and AUF1 in the region encoding a consensus motif for two non-identical RNA recognition motifs (RRMs) and Gln-rich motif. We suggest that the similar affinities of laAUF1 and AUF1 for particular A + U-rich elements (ARE) sequences are related to their potencies as mRNA destabilizers.

Effects of low concentrations of nitric oxide on the zona pellucida binding ability of human spermatozoa

OBJECTIVE

To investigate the direct effects of sodium nitroprusside, a nitric oxide donor, on the fertilizing ability of human spermatozoa in vitro.

DESIGN

Prospective, controlled in vitro study.

SETTING

IVF Unit, Medical College Hospital.

PATIENT(S)

Women undergoing conventional IVF.

INTERVENTION(S)

Human spermatozoa samples were incubated with a nitric oxide donor and a nitric oxide quencher, carboxy-imidazolineoxyl N-oxides.

MAIN OUTCOME MEASURE(S)

The capacitation and the acrosome reaction rates were determined by chlortetracycline assay. Sperm zona pellucida binding and sperm penetration into oocytes were determined using the hemizona assay and the human aged zona-free oocyte sperm penetration assay.

RESULT(S)

High concentrations of sodium nitroprusside (10(-3) and 10(-5) M) inhibited sperm motility and viability. In contrast, low concentrations of sodium nitroprusside (10(-7) and 10(-8) M) did not affect motility and resulted in increased capacitation (47 +/- 6% at 10(-7) M, 42 +/- 6% at 10(-8) M, and 24 +/- 4% in controls, respectively, P < 0.01). A twofold increase in the hemizona index occurred compared to the matched control. However, low levels of sodium nitroprusside treatment did not affect the acrosome reaction and human zona-free oocyte sperm penetration rates.

CONCLUSION(S)

Low concentrations of nitric oxide may have some physiologic role in fertilization through the enhancement of capacitation and zona pellucida binding but not by the induction of the acrosome reaction or the facilitation of penetration into oocytes.

Immunopharmacological studies on experimental allergic encephalomyelitis in DA rats

The immunopharmacological profile of experimental allergic encephalomyelitis (EAE) in DA rats was compared to that in Lewis rats, which are commonly used for the study of EAE. DA rats showed higher susceptibility to EAE than Lewis rats. The immunological studies indicate that DA rats showed higher humoral and cellular immune response to myelin basic protein (MBP) than Lewis rats. This is probably due to the susceptible T cells to mitogen and autoreactive T cells to MBP in DA rats. In pharmacological studies, cyclosporin A, FK-506 and prednisolone suppressed the development of EAE in both strains in a similar manner. These results suggest the existence of two different types of T cells with respect to the onset of EAE in DA rats: one is highly reactive to mitogen and MBP; the other is regulated by cyclosporin A and FK-506.

The effect of TRK-530 on experimental arthritis in mice

TRK-530 is a newly synthesized diphosphonate derivative. We investigated the effect of TRK-530 on type II collagen-induced arthritis (CIA) in mice in comparison to that of prednisolone and indomethacin. TRK-530 at a dose of 25 mg/kg showed a tendency to inhibit CIA. TRK-530 at a dose of 50 mg/kg inhibited the development of the CIA in terms of the progression of footpad swelling, bone damage and histopathological changes. TRK-530 at a dose of 50 mg/kg also significantly inhibited the delayed type hypersensitivity (DTH) response to type II collagen, but not the production of anti-type II collagen IgG antibody in arthritic mice. To investigate the inhibitory mechanism of TRK-530, the type of effect of TRK-530 on the production of IL-1 beta in vitro was studied. TRK-530 at a concentration of 10(-4) M inhibited LPS-induced IL-1 beta production from J774.1 cells. In conclusion, TRK-530 inhibited CIA in mice. The inhibition of the DTH reaction to type II collagen and the inhibition of IL-1 beta production may partly participate the anti-rheumatoid action of TRK-530.

Immunopharmacological studies on collagen-induced arthritis in dark Agouti (DA) rats

Dark Agouti (DA) and Lewis rat strains were tested for susceptibility to collagen-induced arthritis (CIA) and for development of cellular and humoral immune responses to type II collagen (CII). All of the DA rats developed arthritis following a single intradermal injection of more than 20 microg of CII (130-150 microg/kg rat weight) and showed a swelling rate of more than 100% in the hind paws. The swelling rate showed little deviation among the animals. There was a strong correlation between the severity of the arthritis and the strength of the immune response to CII in DA rats with CIA. Following immunization with even 800 microg of CII (3.8-4.2 mg/kg rat weight), Lewis rats showed a maximum rate of hind paw swelling of only 45%. In the pharmacological studies, prednisolone, indomethacin, FK-506 and mizoribine all suppressed arthritis in DA rats. These findings suggest that DA rats are more susceptible to CIA than Lewis rats and that CIA in DA rats as well as in Lewis rats is serviceable as an experimental animal model of rheumatoid arthritis.