Furanodictine A and B: amino sugar analogues produced by cellular slime mold Dictyostelium discoideum showing neuronal differentiation activity

We investigated the constituents of Dictyostelium discoideum to clarify the diversity of secondary metabolites of Dictyostelium cellular slime molds and to explore biologically active substances that could be useful in the development of novel drugs. From a methanol extract of the multicellular fruit body of D. discoideum, we isolated two novel amino sugar analogues, furanodictine A (1) and B (2). They are the first 3,6-anhydrosugars to be isolated from natural sources. Their relative structures were elucidated by spectral means, and the absolute configurations were confirmed by asymmetric syntheses of 1 and 2. These furanodictines potently induce neuronal differentiation of rat pheochromocytoma (PC-12) cells.

Recognition of mitochondrial protein precursor lacking arginine at position -2 by mitochondrial processing peptidase: processing of bovine cytochrome P450(SCC) precursor

Mitochondrial processing peptidase (MPP) specifically cleaves off the N-terminal presequence of the mitochondrial protein precursor. Previous studies demonstrated that Arg at position -2 from the cleavage site, which is found among many precursors, plays a critical role in recognition by MPP. We analyzed the structural elements of bovine cytochrome P450 side-chain cleavage enzyme precursor [pre-P450(SCC)], which has Ala at position -2, for recognition by MPP. Replacement of Ala position -2 of pre-P450(SCC) with Arg resulted in an increase in the cleavage rate. Replacement with Gly caused a reduction in the cleavage rate and the appearance of an additional cleavage site downstream of the authentic site. A pre-P450(SCC) mutant with Met at position -2 retained cleavage efficiency equal to that of the wild type. These results indicate that -2 Ala of pre-P450(SCC) is recognized by MPP as a determinant for precise cleavage, and that the amino acid at -2 is required to have a straight methylene chain for interaction with the S(2) site. The preference for distal basic residues, a hydrophobic residue at +1, and hydroxyl residues at +2 and +3, was almost the same as those of the precursors with Arg at -2, indicating that the recognition mechanism of pre-P450(SCC) by MPP is essentially the same as that of the precursors with Arg at position -2.

Increased expression of a nucleolar Nop5/Sik family member in metastatic melanoma cells: evidence for its role in nucleolar sizing and function

F10 and BL6 cells of B16 mouse melanoma cells are metastatic after intravenous injection, but only BL6 cells can metastasize to lungs after subcutaneous injection. Differences in gene expression between the two cell lines were examined, and a greater expression of the Sik-similar protein (Sik-SP) gene was found in BL6 cells. Structurally, Sik-SP belongs to the nucleolar Nop5/Sik family whose members play central roles in ribosome biogenesis; however, the function of Sik-SP has not been examined. Cytology with green fluorescent protein-fused proteins showed that Sik-SP was localized to the nucleolus. To examine whether Sik-SP is involved in ribosome biogenesis, two parameters were measured: magnitude of ribosomal RNA synthesis per nucleus and magnitude of protein production from the same amount of mRNA of an exogenous luciferase gene. Both values and, in addition, nucleolar size were larger in COS-7 monkey kidney cells overexpressing Sik-SP and BL6 cells than in mock-transfected COS-7 and F10 cells, respectively. Sik-SP seemed to promote ribosome biogenesis in the nucleolus. Furthermore, the expression of Sik-SP seemed to confer a greater cell growth response to serum, because such a response was greater in BL6 cells and F10 cells overexpressing Sik-SP than in untreated and mock-transfected F10 cells. Sik-SP may render melanoma cells more competent to survive through augmenting the activity of nucleolus.

Enhanced GM3 expression, associated with decreased invasiveness, is induced by brefeldin A in bladder cancer cells

We reported previously that non-invasive bladder cancer expresses high level of GM3 ganglioside, whereas invasive tumors have low levels. Since glycosphingolipid synthesis in Golgi is modified greatly by a macrocyclic lactone isolated from fungi, brefeldin A (BFA), we studied effects of BFA on expression of glycosphingolipids and on invasiveness of bladder cancer cell lines. Only GM3 synthesis in invasive tumors was greatly enhanced upon treatment with BFA; synthesis of other glycosphingolipids with lacto-series type 2 or globo-series structure in both invasive and non-invasive tumors was not changed. Invasiveness of bladder cancer cells was greatly decreased in association with the great increase of GM3 synthesis induced by BFA treatment. Level of sialyl-Lex expressed in invasive cell line YTS1, which provides the adhesive property of the cells to E-selectin, was unchanged upon BFA treatment. All the bladder cancer cell lines, regardless of invasiveness, highly express tetraspanin CD9. GM3 has been implicated as a co-factor of CD9 in control of tumor cell motility. Down-regulation of CD9 is associated with metastatic properties of tumor cells and survival of patients with colonic cancer. Therefore, enhanced synthesis of GM3 induced by BFA, causing decrease of invasiveness in bladder cancer, is ascribable to the capability of GM3 to interconnect integrin with CD9, in analogy to colonic cancer and perhaps many other types of cancer.

Epidermal growth factor and 1alpha,25-dihydroxyvitamin D3 suppress lipogenesis in hamster sebaceous gland cells in vitro

We have previously reported the establishment of a culture system of hamster auricular sebocytes. Although their morphologic and biochemical properties are very similar to those of human sebocytes, the regulation of lipogenesis is not clear. Therefore, we investigated the effect of epidermal growth factor, all-trans retinoic acid, 1alpha,25-dihydroxyvitamin D3, and androgens such as testosterone and 5alpha-dihydrotestosterone on lipogenesis in cultured hamster sebocytes. Intracellular lipid droplets detected with Oil-Red-O staining were observed in 5 d cultures and increased in a time-dependent manner; 40.7% +/- 1.11% of 2 wk cultured cells tested lipid-positive by flow cytometric analysis. When the hamster sebocytes were cultured in the presence of epidermal growth factor, all-trans retinoic acid, or 1alpha,25-dihydroxyvitamin D3, the intracellular lipid droplets were diminished by all-trans retinoic acid and epidermal growth factor, and slightly by 1alpha,25-dihydroxyvitamin D3. The intracellular lipid droplets consisted mainly of triglycerides (71.8%) and, as minor components, cholesterol (18.0%), wax esters (3.6%), and free fatty acids (6.6%). Epidermal growth factor and all-trans retinoic acid decreased the intracellular accumulation of triglycerides (92.6% and 96.1% inhibition, respectively) and free fatty acids (54.3% and 62.6% inhibition, respectively) in the sebocytes. In addition, 1alpha,25-dihydroxyvitamin D3 decreased the triglyceride level (34.3% inhibition), but augmented the accumulation of wax esters (30% increase). There was no difference in the level of cholesterol as a result of these treatments, however. In contrast, 5alpha-dihydrotestosterone augmented the formation of intracellular lipid droplets along with an increase in the accumulation of triglycerides in hamster sebocytes. Our findings that regulation of lipogenesis by all-trans retinoic acid and androgen in hamster sebocytes is identical to regulation in humans suggest that hamster sebocytes are useful for the elucidation of sebaceous function at the cellular level. Furthermore, this is the first evidence that epidermal growth factor and 1alpha,25-dihydroxyvitamin D3 may act as suppressors in the regulation of lipogenesis in hamster sebocytes in vitro.

[An epidemiological study regarding the hearing acuity of residents in the area with high level of aircraft noise: results of hearing tests conducted in the vicinity of Kadena Air Base]

Hearing tests, primary and secondary, were conducted in two communities vicinal to Kadena US Air Base in Okinawa from May 1996 to July 1998. The noise exposure expressed in WECPNL as designated by the Defense Facilities Administration Agency ranged from 85 to 95 and above. A total of 2035 subjects aged between 25 and 69 years inclusive were considered eligible for inclusion in this study and among them 137 males and 206 females underwent the primary test. Before the test, subjects were asked about hearing difficulty, tinnitus, otological anamnesis and past experience of noise exposure at work and/or hobbies. The primary test was a pure tone audiometry using the ascending method of limits with 5 dB step at 7 test frequencies of 0.5 to 8 kHz. Forty individuals who were judged to have possible noise induced hearing loss were sent to Okinawa Chubu Hospital as subjects for the secondary test. The secondary test consisted of pure tone audiometry with 1 dB step at 9 test frequencies with the addition of 3 kHz and 6 kHz to the primary test frequencies, a Short Increment Sensitivity Index (SISI), test, tympanometry and audioscan audiometry. Based on test findings 12 subjects were considered to have noise induced hearing loss. The examiners interviewed the 12 subjects again to confirm that they had not experienced habitual or repeated intense noise exposure other than aircraft noise exposure around their homes. The geographical distribution of the subject's residences showed their proximity to the airfield, which strongly suggests that the cause of hearing loss may be exposure to aircraft noise from Kadena Air Base.

Nitric oxide increases matrix metalloproteinase-1 production in human uterine cervical fibroblast cells

Since uterine cervical ripening is an active biochemical process similar in part to an inflammatory reaction, nitric oxide (NO) has been proposed as a key mediator of this event. However, the mechanism by which NO modulates human cervical ripening has not been fully elucidated. In the present study we investigated the presence of NO synthases in human uterine cervix by immunohistochemistry and reverse transcriptase-polymerase chain reaction analysis. Furthermore, we examined the presence of NO-mediated regulation of matrix metalloproteinase-1 (MMP-1) production in cultured human uterine cervical fibroblast cells using enzyme-linked immunosorbent assay and Northern blot analysis. Endothelial and inducible NO synthases were detected in the form of mRNA and protein expression in pregnant uterine cervix. Interleukin-1alpha (IL-1alpha) increased the expression of inducible NO synthase mRNA in cultured human uterine cervical fibroblast cells. IL-1alpha also increased MMP-1 secretion from the cultured cervical fibroblast cells. This IL-1alpha-augmented MMP-1 secretion was partially but significantly blocked by an NO synthase inhibitor, N(G)-nitro-L-arginine methyl ester. On the other hand, NO donors increased MMP-1 production in the cultured cervical fibroblast cells. These findings together suggest that NO contributes to the process of cervical ripening via enhancement of MMP-1 production, and that IL-1alpha increases MMP-1 secretion from cervical fibroblasts at least in part via NO synthesis.

Glu(191) and Asp(195) in rat mitochondrial processing peptidase beta subunit are involved in effective cleavage of precursor protein through interaction with the proximal arginine

Mitochondrial processing peptidase (MPP), consisting of alpha and beta subunits, recognizes a large variety of N-terminal extension peptides of mitochondrial precursor proteins, and generally cleaves a single site of the peptide including arginine at the -2 position (P(2)). We obtained evidence that Glu(191) and Asp(195) of rat beta subunit interact with P(2) arginine of precursor protein through ionic and hydrogen bonds, respectively, using recombinant MPP. Mutation to alanines at Glu(191) and Asp(195) reduced processing activity toward precursors with P(2) arginine, but resulted in no loss of activity toward P(2) alanine precursors. Charge-complementary mutation demonstrated that MPP variants with beta Arg(191) exhibited compensatory processing activity for the precursor with acidic residue at the P(2) position. Thus, Glu(191) and Asp(195) are substrate-binding sites required for cleavage of extension peptides through interaction with P(2) arginine.

The modular nature of histone deacetylase HDAC4 confers phosphorylation-dependent intracellular trafficking

In C2C12 myoblasts, endogenous histone deacetylase HDAC4 shuttles between cytoplasmic and nuclear compartments, supporting the hypothesis that its subcellular localization is dynamically regulated. However, upon differentiation, this dynamic equilibrium is disturbed and we find that HDAC4 accumulates in the nuclei of myotubes, suggesting a positive role of nuclear HDAC4 in muscle differentiation. Consistent with the notion of regulation of HDAC4 intracellular trafficking, we reveal that HDAC4 contains a modular structure consisting of a C-terminal autonomous nuclear export domain, which, in conjunction with an internal regulatory domain responsive to calcium/calmodulin-dependent protein kinase IV (CaMKIV), determines its subcellular localization. CaMKIV phosphorylates HDAC4 in vitro and promotes its nuclear-cytoplasmic shuttling in vivo. However, although 14-3-3 binding of HDAC4 has been proposed to be important for its cytoplasmic retention, we find this interaction to be independent of CaMKIV. Rather, the HDAC4.14-3-3 complex exists in the nucleus and is required to confer CaMKIV responsiveness. Our results suggest that the subcellular localization of HDAC4 is regulated by sequential phosphorylation events. The first event is catalyzed by a yet to be identified protein kinase that promotes 14-3-3 binding, and the second event, involving protein kinases such as CaMKIV, leads to efficient nuclear export of the HDAC4.14-3-3 complex.

Heat-inducible TNF-alpha gene therapy combined with hyperthermia using magnetic nanoparticles as a novel tumor-targeted therapy

Heat-induced therapeutic gene expression is highly desired for gene therapy to minimize side effects. Furthermore, if the gene expression is triggered by heat stress, combined therapeutic effects of hyperthermia and gene therapy may be possible. We combined TNF-alpha gene therapy driven by the stress-inducible promoter, gadd 153, with hyperthermia using magnetite cationic liposomes (MCLs). In nude mice, MCLs induced cell death throughout much of the tumor area on heating under an alternating magnetic field. This heat stress also resulted in a 3-fold increase in TNF-alpha gene expression driven by the gadd 153 promoter as compared with that of nonheated tumor. TNF-alpha gene expression was also observed in the peripheral area where the hyperthermic effect was not enough to cause cell death. The combined treatment strongly arrested tumor growth in nude mice over a 30-day period, suggesting potential for cancer treatment.

Triptolide, a novel diterpenoid triepoxide from Tripterygium wilfordii Hook. f., suppresses the production and gene expression of pro-matrix metalloproteinases 1 and 3 and augments those of tissue inhibitors of metalloproteinases 1 and 2 in human synovial fibroblasts

OBJECTIVE

Various extracts of the Chinese herbal remedy Tripterygium wilfordii Hook. f. (TWHF) have been reported to be therapeutically efficacious in rheumatoid arthritis (RA) in China, but their mechanism of action remains unclear. We investigated the effect of triptolide, a diterpenoid triepoxide from TWHF, on the production of pro-matrix metalloproteinase 1 (proMMP-1; or procollagenase 1 or pro-interstitial collagenase 1), proMMP-3 (or prostromelysin 1), tissue inhibitors of metalloproteinases (TIMPs), and proinflammatory cytokines in human synovial fibroblasts and J774A.1 mouse macrophages.

METHODS

Human synovial fibroblasts and mouse macrophages were cultured with interleukin-1alpha (IL-1alpha) or lipopolysaccharide (LPS) in the presence or absence of triptolide. The production of proMMPs 1 and 3, TIMPs 1 and 2, cyclooxygenase 1 (COX-1) and COX-2, prostaglandin E2 (PGE2), IL-1beta, and IL-6 was assayed by Western blot analysis and enzyme-linked immunosorbent assay. Gene expression of proMMPs 1 and 3, TIMPs 1 and 2, COX-1 and COX-2, IL-1alpha, IL-1beta, tumor necrosis factor alpha (TNFalpha), and IL-6 was also monitored by Northern blot analysis and reverse transcriptase-polymerase chain reaction.

RESULTS

Triptolide suppressed the IL-1alpha-induced production of proMMPs 1 and 3 and decreased their messenger RNA levels in human synovial fibroblasts. In contrast, the IL-1alpha-induced gene expression and production of TIMPs 1 and 2 were further augmented by triptolide in the synovial cells. Triptolide also inhibited the IL-1alpha-induced production of PGE2 by selectively suppressing the gene expression and production of COX-2, but not those of COX-1. In addition, triptolide suppressed the LPS-induced production of PGE2 in mouse macrophages. Furthermore, the gene expression of IL-1alpha, IL-1beta, TNFalpha, and IL-6, as well as the production of IL-1beta and IL-6, were inhibited by triptolide in the LPS-treated mouse macrophages.

CONCLUSION

We have demonstrated for the first time that the therapeutic effects of TWHF in RA are due in part to the novel chondroprotective effect of triptolide via the direct suppression of the production of proMMPs 1 and 3 and the simultaneous up-regulation of TIMPs in IL-1-treated synovial fibroblasts. Triptolide's interference with gene expression of proinflammatory cytokines and its known inhibitory effects on PGE2 production are also probably very effective.

Renin-angiotensin system is involved in the mechanism of increased serum asymmetric dimethylarginine in essential hypertension

Endothelium-dependent/nitric oxide (NO)-mediated vasodilation is impaired in hypertensive individuals. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthase, is synthesized by many types of cells including vascular endothelial cells. The serum level of ADMA is elevated in patients with essential hypertension, but the mechanism for this increase is unknown. Therefore, the present study examined whether the renin-angiotensin system (RAS) is involved. Patients with essential hypertension [systolic blood pressure (BP) > 160 mmHg and/or diastolic BP > 95 mmHg] were randomized to an angiotensin-converting enzyme (ACE) inhibitor treatment group (perindopril, 4mg/day for 4 weeks, n = 7), an angiotensin II type 1 (AT1) receptor antagonist treatment group (losartan, 50 mg/day for 4 weeks, n = 7) or a beta-blocker treatment group (bisoprolol, 5 mg/day for 4 weeks, n = 7). Before and after the treatment, BP, serum concentration of ADMA and plasma concentration of von Willebrand factor (vWF, a biological marker of endothelial injury) were measured. Perindopril, losartan and bisoprolol decreased BP to a similar extent, and either perindopril or losartan, but not bisoprolol, significantly decreased serum ADMA and plasma vWF. These findings suggest that the RAS may contribute to the mechanism of increased serum ADMA as well as to the endothelial injury observed in hypertensive patients. The vasculoprotective actions of ACE inhibitors or AT1 receptor antagonists may be explained at least in part by amelioration of the endothelial injury through a decrease in the serum ADMA concentration.

Inhibition of neuronal nitric oxide synthase ameliorates renal hyperfiltration in streptozotocin-induced diabetic rat

Systemic inhibition of nitric oxide synthase (NOS) in streptozotocin-induced (STZ-induced) diabetic rats results in decreases in glomerular filtration rate (GFR) and renal plasma flow (RPF) and an increase in renal vascular resistance (RVR). However, the exact isoform of NOS involved in diabetic renal hyperfiltration has not been determined. This study was conducted to clarify whether NO derived from neuronal NOS is involved in diabetic renal hyperfiltration when using a selective inhibitor of neuronal NOS, 7-nitro indazole (7-NI). Continuous infusion of NG-nitro-L -arginine methyl ester (L-NAME) at 5 microg/kg/min ameliorated renal hyperfiltration, decreased RPF, and increased RVR in diabetic rats without affecting the mean arterial pressure (MAP). 7-NI administered intraperitoneally in diabetic rats significantly reduced GFR without affecting MAP, but the renal hyperfiltration was still observed after the administration of 7-NI. The combined administration of L-NAME after 7-NI caused a further decrease in GFR in diabetic rats and ultimately resulted in normalization of GFR. 7-NI did not change any parameters of renal hemodynamics in control rats. Urinary excretion of nitrite/nitrate and cyclic guanosine monophosphate was significantly increased in diabetic rats over values found in control rats. Our results suggested that a local inhibition of NO in the kidney was involved in the amelioration of diabetic renal hyperfiltration and that NO derived from neuronal NOS is involved, at least in part, in renal hyperfiltration in STZ-induced diabetic rats.

Improved preparation of sulfur substituted 3-vinylpyrrole and its application to the syntheses of chuangxinmycin derivatives

Sulfur substituted 3-vinylpyrrole 10 was prepared from 3-thio-acetylpyrrole 9 by alkylation with alkyl halide in the presence of propylene oxide. Functionalized 4-alkylthioindoles were made by Diels-Alder reaction of the 3-vinylpyrrole 10 with dienophiles. Chuangxinmycin analogues were synthesized by using some of the functionalized 4-alkylthioindoles as key intermediates.

[Isolated cerebral and myocardial perfusion during aortic arch repair in neonates]

OBJECTIVES

To prevent possible neurologic injury after hypothermic circulatory arrest, aortic arch obstruction with cardiac defects is repaired in one stage using isolated cerebral and myocardial perfusion (ICMP). This study investigated serum S-100 protein(S-100) levels in neonates undergoing ICMP.

METHODS

Between February 2000 and January 2001, 19 neonate patients underwent repair of critical congenital heart defects. Seven of these patients with aortic coarctation(n = 3) or interrupted aortic arch (n = 4) with ventricular septal defect(ICMP group) underwent primary total repair. An arterial cannula was inserted either into the ascending aorta or into a polytetrafluoroethylene graft which was anastomosed to the innominate artery. During arch repair, a cross-clamp was placed between the innominate and left carotid arteries, and an end-to-end arch anastomosis was performed with cerebral perfusion and heart beating. During ICMP the flow was reduced to maintain a radial artery pressure of 30-45 mmHg. The remaining 12 patients underwent complete transposition of great arteries(n = 9) or total anomalous pulmonary venous connection(n = 3) using a cardiopulmonary bypass(CPB) with flow of 150-180 ml/kg/min(control group). Sequential blood samples for S-100 determinations were taken after induction of anesthesia, 30 min after aortic declamping(post-ACC), 30 min after CPB, and 24 hr after CPB.

RESULTS

There were no early and late deaths. Neurologic symptoms were not observed in any patients. Mean ICMP time in ICMP group was 17 +/- 4 min. In all patients, S-100 showed the highest value post-ACC and then declined with time. There were no differences in S-100 between the groups at any other time point.

CONCLUSIONS

Selective cerebral perfusion through the innominate artery may be able to maintain brain circulation.

[Anti-nociceptive effect of calcitonin on chronic pain associated with osteoporosis]

Calcitonin is widely used clinically for alleviating hyperalgesia as well as recovering bone mass associated with osteoporosis. However, it's analgesic mechanism is not clear, although involvement of serotonergic system is suggested. We investigated a mechanism of calcitonin actions using ovariectomized rats which exhibit hyperalgesia. Whole-cell patch-clamp recording was employed to test an effect of calcitonin on synaptic transmission in the dorsal horn. In normal rats, transmitter release from fine myelinated Adelta and unmyelinated C afferents was depressed by serotonin, while the effect of 5-HT on C afferents was disappeared in OVX rats. This elimination of the 5-HT action was reversed by administration of calcitonin.

Binding specificity of siglec7 to disialogangliosides of renal cell carcinoma: possible role of disialogangliosides in tumor progression

Previous studies indicate that expression of higher gangliosides in renal cell carcinoma (RCC) is correlated with metastatic potential, particularly in the lung. Out of five major gangliosides in RCC, three disialogangliosides (disialogalactosylgloboside, IV(3)NeuAcIII(6)NeuAcLc(4), and IV(4)GalNAcIV(3)NeuAcIII(6)NeuAcLc(4)) bind strongly to siglec7, which is expressed highly in monocytes and natural killer cells. Out of other gangliosides tested, 2-->6 sialylparagloboside, GD3, GD2, and GT1b, but not other lacto- or ganglio-series gangliosides, showed clear binding to siglec7. In view of preferential metastasis of RCC to the lung, and binding of RCC cell line TOS-1 to lung tissue sections as shown in our previous study, we examined expression of siglec7 in the lung. siglec7 is expressed highly in resident blood cells, but not in parenchymatous cells. TOS-1 cells aggregate together strongly through adhesion with peripheral blood mononuclear cells to form large clumps. This suggests the possibility that such aggregates may form embolisms of microvasculature, particularly in the lung, which initiate metastasis. Other possible roles of higher gangliosides in RCC in promoting metastasis and tumor progression are discussed.

Differential roles of cytokine receptors in the development of epidermal gamma delta T cells

IL-7 and IL-15 play important roles in gammadelta T cell development. These receptors transmit proliferation and/or survival signals in gammadelta T cells. In addition, the IL-7R promotes recombination and transcription in the TCR gamma locus. To clarify the role of the cytokine receptors in the development of epidermal gammadelta T cells, we introduced a Vgamma3/Vdelta1 TCR transgene, derived from Thy-1+ dendritic epidermal T cells (DETC), into IL-7Ralpha-deficient mice, and we found that they partly rescued gammadelta T cells in the adult thymus but not in the spleen. Introduction of an additional Bcl-2 transgene had a minimal effect on gammadelta T cells in the adult thymus of these mice. In contrast to the adult thymus, the introduction of the Vgamma3/Vdelta1 TCR transgene into IL-7Ralpha-/- mice completely restored Vgamma3+ T cells in the fetal thymus and DETC in the adult skin. On the contrary, the same Vgamma3/Vdelta1 TCR transgene failed to rescue DETC in the skin of IL-2Rbeta-deficient mice, even with the additional Bcl-2 transgene. These results suggest that the IL-2/IL-15R, rather than the IL-7R, plays an essential role in proliferation and survival of DETC in the fetal thymus and the skin. In contrast, the IL-7R is probably essential in the induction of V-J recombination of TCRgamma genes. Thus, this study proves that IL-7R and IL-2/IL-15R serve differential functions in epidermal gammadelta T cell development.

[Bacterial contamination of salvaged blood in open heart surgery: is that an airborne contamination or a normal skin flora contamination?]

We investigated sources of bacterial contamination of intraoperative salvaged blood producted by autologous transfusions device (CS; CELL SAVER 5, Heamonetics Corp., Braintree, MA). Eleven patients undergone open heart surgeries including 2 emergency operations with a median sternotomy enrolled in this study. Blood samples were drawn from salvaged blood bags. Airborne contaminants (AB) were collected by a blood agar plate put besides the operation bed for 30 minutes. The median wounds samples were collected by a swab. Bacterial growth was detected in 81.8% of salvaged blood samples. Twenty-nine bacterium were isolated from CS, 72.4% of those were Staphylococci. 9.1% of sample was positive in wound swabs. Forty bacterium were isolated from plate cultures. 65% of them were Staphylococci. Staphylococcus epidermidis and coagulase negative Staphylococcus isolated both CS and AB in the 2 cases had the same identify codes, and incubated from several AB cultures. Corynebacterium sp. is also isolated from both CS and AB cultures in other 2 same cases. In 7 out of 8 cases (87.5%), from which Staphylococci isolated in CS, the Staphylococci were cultured from AB in not the same but the other cases. In conclusion, highly incidence of the identification in identical code of Staphylococci indicated that the main source of CS contamination was highly suspected to AB.

Suppression by estrogen receptor beta of AP-1 mediated transactivation through estrogen receptor alpha

The estrogen receptor (ER) is known to mediate gene transcription from AP-1 enhancer elements as well as the well-documented estrogen responsive elements (EREs). Investigations of AP-1 mediated transactivation through ER have been performed with rather complex promoters such as insulin like growth factor 1 (IGF-1) and collagenase promoters. In the present study, we investigated AP-1 mediated transactivation through ERalpha and ERbeta with a less complicated reporter consisting of only consensus AP-1 motifs. NIH 3T3 cells were transiently transfected with human ERalpha and ERbeta expression plasmids and AP-1-luc and ERE-luc reporters. 17beta-Estradiol failed to activate ERbeta-AP-1 responses while activating ERalpha-AP-1, ERalpha-ERE, ERbeta-ERE mediated transcription. On the other hand, antiestrogens such as tamoxifen enhanced AP-1 mediated transactivation through both ERalpha and ERbeta. An ERalpha positive human breast cancel cell line, MCF-7, also showed the same manner of AP-1 mediated transactivation through ERalpha. When NIH 3T3 with ERalpha and MCF-7 were co-transfected with ERbeta, E2 dependent AP-1 responses decreased in both cell lines depending on the amount of the ERbeta expression plasmid. These results suggest that ERalpha and ERbeta may function in opposition with ERbeta actually suppressing the function of ERalpha in AP-1 mediated transactivation.

Crystal structures of mitochondrial processing peptidase reveal the mode for specific cleavage of import signal sequences

BACKGROUND

Mitochondrial processing peptidase (MPP) is a metalloendopeptidase that cleaves the N-terminal signal sequences of nuclear-encoded proteins targeted for transport from the cytosol to the mitochondria. Mitochondrial signal sequences vary in length and sequence, but each is cleaved at a single specific site by MPP. The cleavage sites typically contain an arginine at position -2 (in the N-terminal portion) from the scissile peptide bond in addition to other distal basic residues, and an aromatic residue at position +1. Mitochondrial import machinery recognizes amphiphilic helical conformations in signal sequences. However, it is unclear how MPP specifically recognizes diverse presequence substrates.

RESULTS

The crystal structures of recombinant yeast MPP and a cleavage-deficient mutant of MPP complexed with synthetic signal peptides have been determined. MPP is a heterodimer; its alpha and beta subunits are homologous to the core II and core I proteins, respectively, of the ubiquinol-cytochrome c oxidoreductase complex. Crystal structures of two different synthetic substrate peptides cocrystallized with the mutant MPP each show the peptide bound in an extended conformation at the active site. Recognition sites for the arginine at position -2 and the +1 aromatic residue are observed.

CONCLUSIONS

MPP bound two mitochondrial import presequence peptides in extended conformations in a large polar cavity. The presequence conformations differ from the amphiphilic helical conformation recognized by mitochondrial import components. Our findings suggest that the presequences adopt context-dependent conformations through mitochondrial import and processing, helical for recognition by mitochondrial import machinery and extended for cleavage by the main processing component.

Light microscopic observations of infraciliature and morphogenesis in six species of rumen Ostracodinium ciliates

Infraciliature and morphogenesis of six rumen ciliates, Ostracodinium mammosum, O. munham, O. dilobum, O. rugoloricatum, O. iwawoi, and O. tiete are described from pyridinated silver carbonate-impregnated specimens. These six Ostracodinium have a similar polybrachykinety arrangement, distinct from that of other ophryoscolecid ciliates and intermediate between those of O. gracile and 0. damaliscus. Buccal infraciliature is composed of three polybrachykineties, a kinety loop, and paralabial kineties. Small dorso-adoral polybrachykinety, slender vestibular polybrachykinety, and kinety loop are characteristic. Dorsal infraciliature consists of the dorsal polybrachykinety that extends laterally along the dorsal side of the body. Morphogenesis is different from that of O. gracile, because the right end of ventral primordium extends dorsally to grow into a right primordium without separation.

Estrogen treatment down-regulates TNF-alpha production and reduces the severity of experimental autoimmune encephalomyelitis in cytokine knockout mice

A shift toward Th2 cytokine production has been demonstrated during pregnancy and high dose estrogen therapy and is thought to be the primary mechanism by which estrogen suppresses the development of experimental autoimmune encephalomyelitis. However, low dose estrogen treatment is equally protective in the absence of a significant shift in cytokine production. In this study cytokine-deficient mice were treated with estrogen to determine whether a shift in Th2 cytokine production was required for the protective effects of hormone therapy. Estrogen effectively suppressed the development of experimental autoimmune encephalomyelitis in IL-4 and IL-10 knockout mice and in wild type littermate mice with a similar potency of protection. Significant disease suppression was also seen in IFN-gamma-deficient mice. The decrease in disease severity was accompanied by a concomitant reduction in the number of proinflammatory cytokine- and chemokine-producing cells in the CNS. Although there was no apparent increase in compensatory Th2 cytokine production in cytokine-deficient mice, there was a profound decrease in the frequency of TNF-alpha-producing cells in the CNS and the periphery. Therefore, we propose that one mechanism by which estrogen protects females from the development of cell-mediated autoimmunity is through a hormone-dependent regulation of TNF-alpha production.

[Susceptibilities of bacteria isolated from patients with lower respiratory infectious diseases to antibiotics (1999)]

From October 1999 to September 2000, we collected the specimen from 430 patients with lower respiratory tract infections in 17 institutions in Japan, and investigated the susceptibilities of isolated bacteria to various antibacterial agents and antibiotics and patients' characteristics. Of 515 strains that were isolated from specimen (mainly from sputum) and assumed to be bacteria causing in inflammation, 506 strains were investigated. The breakdown of the isolated bacteria were: Staphylococcus aureus 78, Streptococcus pneumoniae 101, Haemophilus influenzae 104, Pseudomonas aeruginosa (non-mucoid) 58, P. aeruginosa (mucoid) 11, Moraxella subgenus Branhamella catarrhalis 41, Klebsiella pneumoniae 18, etc. Of 78 S. aureus strains, those with 4 micrograms/ml or above of MIC of oxacillin (methicillin-resistant S. aureus: MRSA) occupied 57.7%. Vancomycin and arbekacin showed the most potent activities against MRSA without detection of ABK-resistant strain (MIC: 64 micrograms/ml) and decrease of VCM-sensitive strains those were found in 1998. The frequency of S. pneumoniae exhibiting low sensitivity to penicillin (penicillin-intermediate S. pneumoniae: PISP + penicillin-resistant S. pneumoniae: PRSP) decreased to 34.7% from 46.0% in 1998. The frequency of PRSP was 3.0%, being the least number after 1991. Carbapenems showed strong activities against S. pneumoniae. Especially, panipenem inhibited the growth of all 101 strains with MIC of 0.063 microgram/ml. Generally, all drugs showed strong activities against H. influenzae with MIC80s of 4 micrograms/ml or below. MICs of ofloxacin ranged between 0.063 microgram/ml and 4 micrograms/ml in 1998, however, those were 0.125 microgram/ml or below in all H. influenzae in 1999 showing the strongest activity. Tobramycin and ciprofloxacin showed strong activities against P. aeruginosa (both mucoid and non-mucoid) with MIC80s of 1 microgram/ml. Number of isolated P. aeruginosa (mucoid) was little as 11, however, the susceptibilities to all drugs were better than P. aeruginosa (non-mucoid). K. pneumoniae showed good susceptibilities to all drugs except for ampicillin with decreasing of low-sensitive strains compared to those detected in 1998. Also, all drugs generally showed strong activities against M. (B.) catarrhalis. MIC80s of all drugs were 2 micrograms/ml or below. The drug which showed the strongest activity was imipenem inhibiting all 41 strains with MIC of 0.063 microgram/ml. On the patients' characteristics, the number of patients aged 80 years or older who had been increased was decreased in 1999 in the distribution by age. The percentage of the elderly patients aged 70 years or older was 47.0%, which occupied almost a half number of the total patients as in the last year. As for the incidence by disease, bacterial pneumonia and chronic bronchitis were the highest. They were noted in 37.9% and 30.5% of the patients, respectively. In 1999, bronchial asthma was frequently observed as compared in recent years. It was noted in about 10% of the patients which is the same % as in bronchiectasis. We examined the number of strains from these patients with infections before and after administration of antibiotics. In patients with bacterial pneumonia, the number of isolated strains was almost the same between those before and after administration. However, in patients with chronic bronchitis, the number of strains remarkably decreased to less than the half of the total after administration of antibiotics in the last year, but it decreased to 2/3 of the total in 1999. On the administration of antibiotics and isolated bacteria by the day of administration, the bacteria which were isolated more before administration were H. influenzae in 28.4%, S. pneumoniae in 25.7%, M. (B.) catarrhalis in 12.0% and S. aureus in 10.6%. The frequency of S. aureus after administration over 15 days was almost the same as that before administration, but the frequency of P. aeruginosa (both mucoid and non-mucoid) was 36.8% which was higher than that before administration. The frequency of isolated S. pneumoniae was decreased after administration and none of them was isolated after completion of administration. However, that of H. influenzae was decreased to 7.1% after administration within 3 days, and many H. influenzae were isolated after completion of administration as 21.4%.

Recent advances in US diagnosis of pancreatic cancer

Recent years have seen dramatic developments in extracorporeal ultrasonography: Color, including-power Doppler ultrasonography, ultrasonography angiography, harmonic imaging (tissue harmonic imaging and contrast harmonic imaging) and 3-dimensional ultrasonography (including virtual endoscopy). In this report, we describe the present situation and the prospective outlook for these new diagnostic modalities mainly on the basis of our own experiences.

Neutral liposome-mediated delivery process of fluorescein-modified oligonucleotides in cultured human keratinocytes

We propose a model of the intracellular delivery process in which fluorescein-labeled natural oligonucleotides (F-DNA) are transferred into the nuclei of cultured human keratinocytes. By encapsulation in neutral multilamellar lecithin liposomes, the F-DNA appeared to be protected against intracellular interactions with cellular materials and nuclease attacks in the cytoplasm during the process. The intracellular behavior of F-DNA and fluorescent phospholipid-labeled liposomes was observed by means of fluorescence analysis. Results showed that: F-DNA encapsulated in neutral multilamellar liposomes reached the cellular nuclei more efficiently than either free F-DNA, or F-DNA in unilamellar liposomes; the liposomal membranes appeared to be left in the cytoplasm. The reaction of F-DNA with complementary DNA was suggested by a rapid quenching of the fluorescence in the nucleus. In addition, the fluorescence decrease was evidently suppressed in the cytoplasm, indicating a protective effect of the neutral multilamellar liposomes against the interaction of F-DNA with cytoplasmic materials. The application of these findings to 'photo'-antisense studies has been discussed, where suppression of a gene expression is attempted by using oligonucleotide-attached fluorescein with the aid of a photo-induced covalent binding property.

Opacification of isolated rat lenses intoxicated with diethylmaleate: relation to lens membrane dysfunction

We examined whether opacification of rat lenses treated with diethylmaleate (DEM), a depletor of reduced glutathione (GSH), is associated with membrane dysfunction. When isolated rat lenses were incubated with 2 mM DEM for 1, 6, and 24 h, a cortical opacity appeared at 6 h and was more pronounced at 24 h. This opacification was accompanied by decreases in GSH and vitamin E (Vit. E) content and Na+,K+-ATPase activity, and an increase in water content, but not by a change in the content of thiobarbituric acid reactive substances (TBARS), an index of lipid peroxidation. Vit. E co-treatment caused a partial prevention of opacification, a complete recovery of decreased Vit. E content, attenuation of decreased Na+,K+-ATPase activity, and a decrease in TBARS content in rat lenses treated with 2 mM DEM for 24 h. Neither opacity formation nor changes in Vit. E, TBARS, and water content and Na+,K+-ATPase activity occurred in rat lenses treated for 48 h with 2 mM l-buthionine-(S,R)-sulfoximine, an inhibitor of glutathione synthesis, although a marked GSH depletion was observed. These results suggest that opacification of isolated rat lenses treated with DEM could be associated with impairment of Na+,K+-ATPase rather than GSH depletion.

Binding specificity of siglec7 to disialogangliosides of renal cell carcinoma: possible role of disialogangliosides in tumor progression

Previous studies indicate that expression of higher gangliosides in renal cell carcinoma (RCC) is correlated with metastatic potential, particularly in the lung. Out of five major gangliosides in RCC, three disialogangliosides (disialogalactosylgloboside, IV(3)NeuAcIII(6)NeuAcLc(4), and IV(4)GalNAcIV(3)NeuAcIII(6)NeuAcLc(4)) bind strongly to siglec7, which is expressed highly in monocytes and natural killer cells. Out of other gangliosides tested, 2-->6 sialylparagloboside, GD3, GD2, and GT1b, but not other lacto- or ganglio-series gangliosides, showed clear binding to siglec7. In view of preferential metastasis of RCC to the lung, and binding of RCC cell line TOS-1 to lung tissue sections as shown in our previous study, we examined expression of siglec7 in the lung. siglec7 is expressed highly in resident blood cells, but not in parenchymatous cells. TOS-1 cells aggregate together strongly through adhesion with peripheral blood mononuclear cells to form large clumps. This suggests the possibility that such aggregates may form embolisms of microvasculature, particularly in the lung, which initiate metastasis. Other possible roles of higher gangliosides in RCC in promoting metastasis and tumor progression are discussed.

Monoclonal antibody (5F3) defining renal cell carcinoma-associated antigen disialosyl globopentaosylceramide (V3NeuAcIV6NeuAcGb5), and distribution pattern of the antigen in tumor and normal tissues

Renal cell carcinoma (RCC) has been characterized by high expression of three types of disialogangliosides: two based on lacto-series type 1 structure (disialosyl Lc(4), GalNAc disialosyl Lc(4)), the other based on globo-series structure (disialosyl globopentaosylceramide; disialosyl Gb5). The present study established a mAb, 5F3, directed to disialosyl Gb5. 5F3 was established after immunization with RCC cell line ACHN. The major disialoganglioside antigen isolated from ACHN cells, showing specific reactivity with 5F3, was characterized unequivocally as disialosyl Gb5 (V(3)NeuAcIV(6)NeuAcGb5) by identification of the core structure as globopentaosylceramide (Gb5) after enzymatic and acid hydrolysis, and by 2-dimensional (1)H-NMR spectroscopy. 5F3 does not react with monosialosyl Gb5 (V(3)NeuAcGb5), Gb5, or any lacto-series structures. 5F3 strongly stained 19 of 41 cases of primary RCC tissue. It reacted with proximal tubules (but not distal tubules) of kidney, microglial cells of cerebrum and cerebellum, goblet cells of stomach and intestine, smooth muscle of various organs. It did not react with parenchymatous cells of various organs, except for kidney epithelia and prostate stroma. Immunostaining of RCC tissue by mAb 5F3, in combination with staining by other antibodies directed to globo-series and lacto-series structures, has prognostic significance in defining metastatic potential of RCC.

Cyclin G1 is involved in G2/M arrest in response to DNA damage and in growth control after damage recovery

Cyclin G1 is one of the target genes of the transcription factor p53, and is induced in a p53-dependent manner in response to DNA damage. Although cyclin G1 has been implicated in a range of biological phenomena, its precise function remains unclear. Here we present an analysis of the physiological role of cyclin G1 using mice homozygous for a targeted disruption of the cyclin G1 gene. In order to clarify the role of cyclin G1 in the p53 pathway, downstream events such as apoptosis, cell growth and cell cycle checkpoint control were analysed in thymocytes and embryonic fibroblasts derived from cyclin G1-disrupted mice. No difference was detected in induction of apoptosis between mouse embryo fibroblasts (MEFs) derived from cyclin G1+/+ and cyclin G1-/- mice. Following irradiation, cyclin G1-/- MEFs proliferated more slowly and reached lower cell densities in culture dishes than cyclin G1+/+ MEFs. Analysis of cell survival showed that cyclin G1-/- MEFs were about twice as sensitive as cyclin G1+/+ MEFs to gamma radiation or UV radiation. Cyclin G1-/- mice were more sensitive to gamma radiation than wild-type mice. Flow cytometeric analysis revealed that the number of cyclin G1-/- MEFs in G2/M phase after irradiation was reduced by 50% relative to cyclin G1+/+ MEFs. Our results demonstrate that cyclin G1 plays roles in G2/M arrest, damage recovery and growth promotion after cellular stress.

A novel ganglioside isolated from renal cell carcinoma

In renal cell carcinoma (RCC), the level of higher gangliosides is correlated with degree of metastatic potential, and cell lines derived from metastatic deposits of RCC are characterized by high expression of disialogangliosides (Saito, S., Orikasa, S., Ohyama, C., Satoh, M., and Fukushi, Y. (1991) Int. J. Cancer 49, 329-334 and Saito, S., Orikasa, S., Satoh, M., Ohyama, C., Ito, A., and Takahashi, T. (1997) Jpn. J. Cancer Res. (Gann) 88, 652-659). We now report two disialogangliosides, G1 and G2, found in the RCC cell line TOS-1. G1 from TOS-1 cells was characterized as having a novel hybrid structure between ganglio-series (region I as in Structure; same as the terminal structure of ganglioside GM2), and the lacto-series type 1 (region II). The characterization was based on reactivity with various monoclonal antibodies (mAbs) with defined epitope specificity, as well as monosaccharide and fatty acid component analysis, (1)H NMR spectroscopy, and electrospray ionization mass spectrometry of the intact compound. G1 showed strong reactivity with mAb RM2, raised originally against TOS-1 cells, and weak cross-reactivity with anti-GM2 mAb MK-1-8. The antigen is hereby termed GalNAc disialosyl Lc4Cer (IV4GalNAcIV3NeuAcIII6NeuAcLc4; abbreviated GalNAcDSLc4). G2 was identified by 1H NMR and mass spectrometry as having a structure similar to Structure but without the GalNAcbeta1-->4 substitution and showed strong reactivity with mAb FH9 reported previously to be specific for disialosyl lacto-series type 1 (disialosyl Lc(4)) having vicinal alpha2-->3 and alpha2-->6 sialosyl residues, an antigen associated with human colonic cancer. Clinicopathological studies indicate that expression of these disialoganglioside antigens in RCC tissue is correlated with the metastatic potential of RCC.

Risk factors for development of postoperative hypertension

One hundred and eighty-nine patients who underwent digestive tract surgery were studied to investigate risk factors for the development of postoperative hypertension. We examined factors related to maximum postoperative systolic blood pressure and postoperative hypertensive urgency, a sign of postoperative hypertension. Data collected included blood pressure, age, sex, body mass index (BMI), medical history, total water balance and grade of surgical stress. Maximum postoperative systolic blood pressure and incidence of postoperative hypertensive urgency were the dependent variables. Mean preoperative systolic blood pressure, age and BMI were significantly related to maximum postoperative systolic blood pressure and postoperative hypertensive urgency. In addition, the grade of surgical stress was significantly related to maximum postoperative systolic blood pressure. In analyses of multiple variables, the adjusted odds ratio for postoperative hypertensive urgency was 1.16 for every 1 mmHg increase in mean preoperative systolic blood pressure, 1.05 for every 1 year increase in age and 0.82 for every 1 kg/m2 increase in BMI. These findings may have important clinical implications for the prevention of postoperative hypertension.

Immunodiagnostic differentiation of alveolar and cystic echinococcosis using ELISA test with 18-kDa antigen extracted from Echinococcus protoscoleces

Immunoblotting analysis was carried out using crude extracts of Echinococccus multilocularis and E. granulosus. A total of 214 serum samples were examined for the detection of antibody responses against 18-kDa polypeptides (Eg18 and Em18). Of 44 sera from patients with alveolar echinococcosis (AE) 91% were positive against both Eg18 and Em18, compared with 10% and 13%, respectively, of 70 cystic echinococcosis (CE) samples and 13% and 17% of 29 cysticercosis samples. A relatively purified 18-kDa antigen was extracted from E. granulosus protoscoleces and an 18-kDa-ELISA test which is simple, fast and highly sensitive and specific has been established. A comparative ELISA analysis, using the purified 18-kDa antigen and pooled AE and CE serum, indicated that there are significant differences in antibody levels between AE and CE sera. The maximum ratio for the evaluation of AE to CE was 2.26. The 18-kDa-ELISA was positive for 91% (40/44) and 11% (8/70) of AE and CE sera, respectively, and there was no cross-reactivity with cysticercosis sera or healthy controls. The overall diagnostic values of 18-kDa-ELISA for AE sera were sensitivity 91%, specificity 94%, positive predictive value 83% and negative predictive value 97%. We conclude that (i) the 18-kDa antigenic component may not be species specific but (ii) levels of antibody to the 18-kDa antigen are significantly different between AE and CE sera. Therefore, the 18-kDa antigen can be a reliable serological marker for differentiation of AE from CE.

Discovery of novel inducers of cellular differentiation using HL-60 promyelocytic cells

Non-physiological inducers of terminal differentiation have been used as novel therapies for the prevention and therapy of cancer. We have used cultured HL-60 promyelocytic cells to monitor differentiation, proliferation and cell death events as induced by a large set of extracts derived from plants. Screening of more than 1400 extracts led to the discovery of 34 with potent activity (ED50 <8 mg/ml). Bioassay-guided fractionation led to the isolation of zapotin and 2',5,6-trimethoxyflavone as active principles from Casimiroa edulis, dibenzyltrisulfide and 2-[(phenylmethyl)dithio]ethanol as active principles from Petiveria alliacea, and desmethylrocaglamide from Aglaia ponapensis. Zapotin demonstrated the most favorable biological profile in that induction of differentiation correlated with proliferation arrest, and a lack of cytotoxicity. We conclude that the HL-60 cell model is a useful system for the discovery of novel pharmacophores with potential to suppress the process of carcinogenesis, and that flavonoids may be especially useful in this capacity.

Heat shock-mediated transient increase in intracellular 3',5'-cyclic AMP results in tumor specific suppression of membrane type 1-matrix metalloproteinase production and progelatinase A activation

We have previously reported that heat shock suppresses the production and gene expression of membrane type 1-matrix metalloproteinase (MT1-MMP) and thereby inhibits the activation of progelatinase A/proMMP-2 in human fibrosarcoma HT-1080 cells and human squamous carcinoma A431 cells and SAS cells (Sato et al. Biochem Biophys Res Commun 1999; 265: 189-93). In an effort to clarify the heat shock-mediated signal transduction pathways, an intracellular cAMP level was found to be transiently augmented in the heat shocked HT-1080 cells. When HT-1080 cells were pretreated with cAMP elevating reagents, forskolin and dibutyryl cAMP for 4 h instead of heat shock and then maintained in a fresh medium, the production and gene expression of MT1-MMP were similarly suppressed. The MT1-MMP-mediated activation of proMMP-2 was also inhibited in the forskolin- and dibutyryl cAMP-treated HT-1080 cells. Furthermore, the transiently augmented cAMP by forskolin as well as heat shock interfered with in vitro invasive activity of HT-1080 cells. In contrast, in normal human fibroblasts neither heat shock nor cAMP elevating reagents altered the concanavalin A-augmented MT1-MMP production and proMMP-2 activation. These results suggest that a transient increase in intracellular cAMP is a critical signal for heat shock to induce tumor specific-suppression of MT1-MMP production and proMMP-2 activation.

Inhibitory effect on natural killer activity of microphthalmia transcription factor encoded by the mutant mi allele of mice

The mouse mi locus encodes a basic-helix-loop-helix-leucine zipper-type transcription factor, microphthalmia transcription factor (MITF). Mice of mi/mi genotype express a mutant form of MITF (mi-MITF), whereas mice of tg/tg genotype have a transgene in the 5' flanking region of the mi gene and do not express MITF. Although the mi/mi mouse is deficient in natural killer (NK) activity, it was found that the tg/tg mouse was normal in this respect. To know the cause, spleen cells of both genotypes were compared. Although the proportion of spleen cells expressing an NK cell marker, NK1.1, was comparable in both mice, the proportion of large granular lymphocytes decreased only in mi/mi mice. The difference between mi/mi and tg/tg mice was reproducible in the culture supplemented with interleukin-2. Moreover, the perforin gene expression was reduced in mi/mi-cultured spleen cells. Wild-type (+) MITF transactivated, but mi-MITF suppressed, the perforin gene promoter through the NF-P motif, a strong cis-acting element. However, neither +-MITF nor mi-MITF bound the NF-P motif. Instead, 2 nuclear factors that bound the NF-P motif were retained in the cytoplasm of mi/mi-cultured spleen cells. In addition, overexpression of mi-MITF resulted in cytoplasmic retention of the 2 NF-P motif-binding factors in cytotoxic T lymphocytes. The presence of mi-MITF rather than the absence of +-MITF appeared to lead to poor transactivation of the NF-P motif by intercepting NF-P motif-binding factors. This inhibitory effect of mi-MITF may cause the deficient cytotoxicity of NK cells in mi/mi mice. (Blood. 2001;97:2075-2083)

Importance of leucine zipper domain of mi transcription factor (MITF) for differentiation of mast cells demonstrated using mi(ce)/mi(ce) mutant mice of which MITF lacks the zipper domain

The mi transcription factor (MITF) is a basic helix-loop-helix leucine zipper (bHLH-Zip) transcription factor that is important for the development of mast cells. Mast cells of mi/mi genotype express normal amount of abnormal MITF (mi-MITF), whereas mast cells of tg/tg genotype do not express any MITFs. Mast cells of mi/mi mice show more severe abnormalities than those of tg/tg mice, indicating that the mi-MITF possesses the inhibitory function. The MITF encoded by the mi(ce) mutant allele (ce-MITF) lacks the Zip domain. We examined the importance of the Zip domain using mi(ce)/mi(ce) mice. The amounts of c-kit, granzyme B (Gr B), and tryptophan hydroxylase (TPH) messenger RNAs decreased in mast cells of mi(ce)/mi(ce) mice to levels comparable to those of tg/tg mice, and the amounts were intermediate between those of +/+ mice and those of mi/mi mice. Gr B mediates the cytotoxic activity of mast cells, and TPH is a rate-limiting enzyme for the synthesis of serotonin. The cytotoxic activity and serotonin content of mi(ce)/mi(ce) mast cells were comparable to those of tg/tg mast cells and were significantly higher than those of mi/mi mast cells. The phenotype of mi(ce)/mi(ce) mast cells was similar to that of tg/tg mast cells rather than to that of mi/mi mast cells, suggesting that the ce-MITF had no functions. The Zip domain of MITF appeared to be important for the development of mast cells. (Blood. 2001;97:2038-2044)

Rhein, an active metabolite of diacerein, down-regulates the production of pro-matrix metalloproteinases-1, -3, -9 and -13 and up-regulates the production of tissue inhibitor of metalloproteinase-1 in cultured rabbit articular chondrocytes

OBJECTIVE

Diacerein has proved to be effective in the treatment of osteoarthritis (OA). However, the precise action mechanism of diacerein on OA is not yet fully understood. Therefore, we investigated the effects of rhein, an active metabolite of diacerein, on the production of promatrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinase-1 (TIMP-1) in rabbit articular chondrocytes.

DESIGN

Confluent rabbit chondrocytes were treated for 24 or 48 h with rhein, naproxen or dexamethasone in the presence of recombinant human IL-1alpha (rhIL-1alpha). ProMMP-9/progelatinase B in the culture medium was monitored by gelatin zymography, and proMMP-1/procollagenase 1, proMMP-3/prostromelysin 1, proMMP-13/procollagenase 3 and TIMP-1 were analysed by Western blot analysis. The steady-state levels of proMMP mRNAs were examined by Northern blot analysis. Total MMPs activity was also determined using FITC-labeled casein.

RESULTS

Rhein suppressed the rhIL-1alpha-induced production of proMMPs-1, -3, -9 and -13 in a dose-dependent manner (0.1-30 microM). The suppressed production of proMMPs-1 and -3 was accompanied by a decrease in the steady-state levels of their mRNAs. Interestingly, rhein increased the production of TIMP-1. These observations were further supported by the fact that rhein decreased the apparent total activity of MMPs in the culture medium.

CONCLUSION

We have demonstrated that rhein, an active metabolite of diacerein down-regulates the gene-expression and production of proMMPs and up-regulates the TIMP-1 production. The therapeutic effects of diacerein on OA may be due, at least in part, to the chondroprotective effect of rhein, its active metabolite.

Hormonal regulation of PGE2 and COX-2 production in rabbit uterine cervical fibroblasts

Prostaglandins (PGs) cause uterine contraction to initiate labor at term. We investigated the effect of progesterone and 17beta-estradiol on the production of PGE2 in rabbit uterine cervical fibroblasts. When the cervical fibroblasts were treated with interleukin-1alpha (IL-1alpha), the level of PGE2 was augmented in a time- and dose-dependent manner. The IL-1alpha-augmented PGE2 level was almost completely suppressed by progesterone and 17beta-estradiol at the physiological concentration (0.01 microM), whereas a slight decrease in the basal level of PGE2 was observed in the cervical fibroblasts treated with both hormones at a pharmacological concentration (1 microM). In addition, the level of PGE2 augmented by IL-1alpha was due to the increase of cyclooxygenase (COX) activity, which was inhibited by progesterone and 17beta-estradiol as well as by indomethacin and a specific COX-2 inhibitor, NS-398, but not by the well-known COX-1 inhibitor, aspirin. Furthermore, progesterone and 17beta-estradiol suppressed the IL-1alpha-augmented COX-2 production but not the constitutive production of COX-1 in rabbit uterine cervical fibroblasts. These results suggest that progesterone and 17beta-estradiol prevent the initiation of labor by inhibiting PGE2 production after the suppression of COX-2 production during pregnancy in the rabbit.

Effect of myopia on frequency-doubling perimetry

PURPOSE

To examine the effect of myopia, occasionally associated with glaucomatous eyes, on the results obtained by frequency-doubling perimetry (FDP).

METHODS

Sixty emmetropic or myopic normal volunteers (mean age, 26.2 +/- 0.35 years, mean +/- SEM; range, 19-34) with good visual acuity and without glaucoma were divided into three groups. The groups were emmetropia to low-myopia (mean refractive error, -1.16 +/- 0.23 D), intermediate-myopia (-4.95 +/- 0.17 D), and high-myopia (-8.12 +/- 0.36 D; n = 20 each). All subjects were tested on the FDP full-threshold C-20 program and the Humphrey Field Analyzer (HFA; Humphrey, Dublin, CA) full-threshold program on one randomly selected eye. FDP and the HFA test were conducted with the subjects wearing their full distance correction and with their distance correction with appropriate additional correction for near, respectively. The calculated mean sensitivity (MS), mean deviation (MD), pattern standard deviation (PSD), and test durations for FDP and the HFA test for the three groups were compared using one-way analysis of variance. The relationship between the refractive error and MS, MD, or PSD was also analyzed by simple regression analysis.

RESULTS

The MS and MD for the fields determined by the HFA decreased significantly as the refractive errors increased, but there were no significant differences in the MS, MD, and PSD for FDP between the three groups. There were no significant differences in the test durations between the three groups for both FDP and HFA testing. The refractive error was correlated with both MS and MD only for the fields determined by the HFA.

CONCLUSIONS

The results showed that lens-corrected myopia does not alter the visual fields obtained by FDP, and FDP can therefore be used regardless of the presence of myopia.

Seroprevalence of antibodies to Chlamydia spp. in human immunodeficiency virus-infected subjects in Japan

To evaluate the seropositivity of Chlamydia spp. in human immunodeficiency virus (HIV)-infected subjects in Japan, Chlamydia-specific antibodies in sera collected from 106 HIV-infected subjects were measured by the microimmunofluorescence test. The prevalence of C. pneumoniae-specific IgA, C. trachomatis-specific IgG and IgA and mean titers were significantly higher in the homosexual and heterosexual HIV-infected subjects than in the hemophilic patients and HIV-negative controls. These data indicate that the higher C. pneumoniae and C. trachomatis seroprevalence among HIV-infected subjects is probably due to an HIV risk factor, such as promiscuous sexual behavior, rather than to HIV infection itself.

Generation of hepatitis C virus-specific cytotoxic T lymphocytes from healthy individuals with peptide-pulsed dendritic cells

BACKGROUND AND AIMS

In hepatitis C virus (HCV) infection, cytotoxic T lymphocytes (CTL) are involved in liver inflammation and contribute to the reduction of viral load. Antibodies for HCV-CTL precursor frequencies (CTLpf) are relatively low in chronic hepatitis C, and this may be related to the poor CTL response in vivo. The aim of this study was to assess the efficacy of dendritic cells (DC) as antigen-presenting cells in CTL generation from low CTLpf.

METHODS

To confirm the rationale of using DC to prime naive T cells, five HCV-uninfected individuals were enrolled in the study. We obtained DC by maturation from peripheral progenitors under stimulation with granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-4 and IL-1alpha. Autologous T cells were cultured with DC or concanavalin-A-induced blasts loaded with four HCV-derived peptides bearing human leukocyte antigen (HLA)-A*0201 or -A24 motifs for 28 days under IL-7 and IL-2 stimulation. The lytic activity against peptide-pulsed targets was assessed by using a [51Cr]-releasing assay.

RESULTS

The DC strongly expressed HLA class I, II, B7-1 and B7-2, but not phenotypic markers of T-, B-, natural killer (NK)-cells or monocytes. The CD8-positive, HLA-class I-restricted and HCV peptide-specific CTL were generated with DC from HLA-A antigen-matched subjects, whereas no CTL activity was detected with concavalin (Con-A) blasts. We were thus able to generate HCV specific CTL from naive precursors with peptide-pulsed DC.

CONCLUSIONS

This DC-based system can be used to generate CTL of desired antigen specificity, even from a source with low CTLpf.

Evaluation of accumulated mucopolysaccharides in the brain of patients with mucopolysaccharidoses by (1)H-magnetic resonance spectroscopy before and after bone marrow transplantation

In seven patients with mucopolysaccharidoses (1 Hurler, 1 Hurler-Scheie, 4 Hunter, 1 Sly), cranial (1)H-magnetic resonance spectroscopy was performed to evaluate the accumulation of mucopolysaccharides and biochemical changes in the CNS in vivo before and after bone marrow transplantation (BMT). In two of seven patients, (1)H-magnetic resonance spectroscopy was performed before and after BMT. Nuclear magnetic resonance spectra of dermatan sulfate and chondroitin sulfate-C and magnetic resonance spectroscopy of chondroitin sulfate-C and urine from patients with mucopolysaccharidoses showed resonance higher than the chemical shift of myoinositol in the brain (3.7 ppm). The resonance was considered to contain signals from mucopolysaccharide molecules. The resonance was measured as presumptive mucopolysaccharides (pMPS). In white matter lesions detected by magnetic resonance imaging, pMPS/creatine ratios and choline/creatine ratios were consistently higher than control ratios. In white matter without lesions, choline/creatine ratios were higher than control ratios. Patients with higher developmental quotient or intelligence quotient tended to show higher N:-acetylaspartate/creatine ratios and lower pMPS/creatine ratios in basal ganglia. After BMT, the pMPS/creatine ratio in white matter lesions of patient 3, with Hunter syndrome, was slightly decreased, but in none of the patients was the ratio ever below the control ratios, even 7 y after BMT. In white matter without lesions, the pMPS/creatine ratio in patient 3 was decreased to the control ratios after BMT, but although the choline/creatine ratios were gradually decreased, they remained higher than the control ratio, 2 y after BMT. These results suggest that evaluation of pMPS, choline, and N:-acetylaspartate by (1)H-magnetic resonance spectroscopy is an important technique that may provide useful biochemical information in vivo on the neurologic process and the efficacy of BMT in patients with mucopolysaccharidoses.

Apoptosis induced by hypertonicity in Madin Darley canine kidney cells: protective effect of betaine

BACKGROUND

In mammals, the renal medulla is in a hypertonic environment related to the renal concentrating mechanism. Renal cells accumulate osmolytes such as betaine to protect cells from the perturbing effect of high concentration of electrolytes. Hypertonicity-induced cell death and the effect of betaine were investigated in Madin Darby canine kidney (MDCK) cells.

METHODS

Cell viability was detected by 3-(4,5-dimethylthiazo-2-yl)-2,5-diphenyl tetrazolium bromide assay. DNA fragmentation was determined by FACS analysis, terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) staining and agarose gel electrophoresis. Activities of caspase-1, -3, -8, and -9 were measured.

RESULT

When the cells were exposed to 700 mOsm medium for 24 h, 40% of the cells were detached. TUNEL staining showed that about 20% of detached cells were apoptotic, indicating that both necrosis and apoptosis contributed to the hypertonicity-induced cell death in MDCK cells. DNA laddering was demonstrated in hypertonic cells. Caspase-3, -8, and -9 activities of the adherent cells exposed to 700 mOsm for 24 h increased approximately 20-, 3-, and 4-fold the value of isotonic cells, respectively. However, there was no significant change in caspase-1 activity. Addition of 1 mM betaine into the medium protected the cells against the hypertonicity-induced cytotoxicity and apoptosis. Betaine prevented the induction of caspase-3, -8, and -9 activities after hypertonic exposure to about 50%.

CONCLUSIONS

The present study demonstrates that (i) apoptosis is involved in the hypertonicity-induced cell death in MDCK cells; (ii) caspase-3, -8, and -9 may contribute to the apoptosis; and (iii) betaine has protective effect on the hypertonicity-induced apoptosis.