Protein synthesis inhibition induces cytoresistance in cultured human proximal tubular (HK-2) cells

After sublethal injury, proximal tubular cells acquire resistance to further attack. This study evaluated whether this could be a possible consequence of decreased protein synthesis, a potential correlate of cell damage. To this end, cultured human proximal tubular cells (HK-2) were subjected to 0-24 h of protein synthesis inhibition (> 98%), either by adding protein synthesis inhibitors [cycloheximide (CH) or verrucarin A] or by inducing sublethal ATP depletion (antimycin A + 2-deoxyglucose). After 24 h of these treatments, significant resistance to Ca2+ ionophore/ATP depletion-induced attack was noted (assessed by vital dye exclusion, compared with normal cells). That < or = 6 h of protein synthesis inhibition caused no cytoresistance implied the importance of evolving protein depletion rather than nonspecific drug effects or protein synthesis inhibition per se. CH plus ATP depletion did not induce additive benefits, suggesting a common mechanism. Cytoresistance was dissociated from the extent of free Ca2+ loading and ATP depletion but was associated with a decrease in membrane deacylation. CH removal promptly restored protein synthesis and cytoresistance was lost; conversely, ATP recovery did not restore protein synthesis and cytoresistance persisted. The emergence of cytoresistance correlated with the disappearance/dephosphorylation of an unidentified 130-kDa tyrosine-phosphorylated protein/protein complex (denoted pp-130). The functional significance of this change was suggested by the fact that tyrosine phosphatase inhibition with orthovanadate maintained pp-130 expression and prevented the cytoresistant state. We conclude that protein synthesis inhibition in HK-2 cells can induce a cytoresistant state. Suppression in phospholipase activity and altered tyrosine phosphorylation events may have functional significance in this regard.

Biological characteristics of neuroblastoma with spontaneous tumor reduction: a case report

The authors examined the biological characteristics of a neuroblastoma with spontaneous tumor reduction. A 6-month-old boy with a pelvic neuroblastoma underwent surgical extirpation of the tumor 1 month after diagnosis. The size of the tumor reduced spontaneously while he was awaiting operation. The low proliferative activity of the tumor cells and the presence of apoptosis in the tumor tissue were shown by an immunohistochemical method using anti-PCNA antibody and a DNA fragmentation analysis, respectively. These results suggest that the spontaneous tumor reduction seen in this patient may well be caused by the overwhelming apoptosis of tumor cells.

Properties of multiphase microspheres of poly(D,L-lactic-co-glycolic acid) prepared by a potentiometric dispersion technique

Multiphase microspheres of poly(D,L-lactic-co-glycolic acid) (PLGA) were prepared by a multiple emulsion potentiometric dispersion technique. Water-soluble compounds were dissolved in the aqueous phase (W) and emulsified in soybean oil (O) to form a stable emulsion. This primary emulsion was dispersed in a solution of PLGA and acetonitrile (O) to form a W/O/O emulsion. The W/O/O emulsion was then dispersed in a hardening solution of light mineral oil (O) using a potentiometric dispersion technique to produce microspheres of the W/O/O/O type with a very narrow and selective size distribution. The size of the microspheres was controlled by varying the internal diameter of the conductive infusion tube or by the variation of voltage applied to the conductive tube. Particle size analysis revealed a particle size distribution of 1-50 microns for microspheres made by this method as compared to a distribution of 50-500 microns for microspheres made by conventional agitation methods. Chlorpheniramine maleate was encapsulated with a loading efficiency of 88.9% with the potentiometric method as compared with a loading efficiency of 74.3% for the agitation method.

Cell-mediated catabolism of aggrecan. Evidence that cleavage at the "aggrecanase" site (Glu373-Ala374) is a primary event in proteolysis of the interglobular domain

A rat chondrosarcoma cell line and primary bovine chondrocytes have been used to study cell-mediated aggrecan catabolism. Addition of 1 microM retinoic acid to chondrosarcoma cultures resulted in aggrecan proteolysis with the release of greater than 90% of the cell layer aggrecan into the medium within 4 days. NH2-terminal sequencing of chondroitin sulfate-substituted catabolic products gave a single major NH2-terminal sequence of ARGNVILTXK, initiating at Ala374. This showed that the proteinase, commonly referred to as "aggrecanase," which cleaves the Glu373-Ala374 bond of the interglobular domain of aggrecan (Sandy, J. D., Neame, P. J., Boynton, R. E., and Flannery, C. R. (1990) J. Biol. Chem. 266, 8683-8685), is active in this cell system. Aggrecan G1 domain, generated by cleavage of the interglobular domain, was also liberated during catabolism and this was characterized with three antipeptide antisera. Anti-CDAGWL was used as a general probe for G1 domain. Anti-FVDIPEN was used to specifically detect G1 domain with COOH terminus of Asn341, the form which is readily generated by cleavage of aggrecan by a wide range of matrix metalloproteinases. Anti-NITEGE antiserum was used to specifically detect G1 domain with COOH terminus of Gln373, the form which is the expected product of "aggrecanase"-mediated cleavage of aggrecan. Western blot analysis indicated that a single form of G1 domain of about 60 kDa was formed. G1 domain of this size reacted with both anti-CDAGWL and anti-NITEGE but not with anti-FVDIPEN. Similar experiments with primary bovine chondrocyte cultures, treated with either retinoic acid or interleukin 1, showed that two forms of catabolic G1 domain, of about 62 and 66 kDa, were formed. Both of these forms reacted on Western blots with anti-CDAGWL and also with anti-NITEGE. It is suggested that cell-mediated catabolism of the aggrecan interglobular domain in these culture systems, whether promoted by retinoic acid or interleukin 1, primarily involves cleavage of the Glu373-Ala374 bond by aggrecanase. The accumulation of G1 domain with a COOH-terminal of Glu373 shows that such aggrecanase-mediated cleavage can occur independent of the cleavage of the Asn341-Phe342 bond by matrix metalloproteinases.

Signaling through CD40 rescues IgE but not IgG or IgA secretion in X-linked immunodeficiency with hyper-IgM

The ligand for CD40 (CD40L) is a membrane protein on activated T cells that induces B cell proliferation and differentiation. Several mutations of the CD40L gene were reported responsible for defective class switching of B cells in an X-linked immunodeficiency with hyper IgM (X-HIM). We studied four affected males from three families and found three independent mutations including new mutations of CD40L gene. In every X-HIM patient tested, however, anti-CD40 plus IL-10 did not induce class switching from IgM to IgG or IgA, even in the presence of Staphylococcus aureus Cowan I strain (SAC). CD4+ T cell clones, expressing CD40L on their surface, also did not rescue IgG or IgA induction by X-HIM peripheral blood B cells in vitro. But signaling through CD40 induced both B cell proliferation and IgE secretion when IL-4 was added to the culture. Taken together, these results show that in vitro signaling through CD40 rescues IgE but not IgG or IgA secretion by peripheral blood X-HIM B cells and suggest that in vivo CD40 and CD40L interaction might be necessary for IgG and IgA differentiation in X-HIM.

Structural organization of the gene for CD40 ligand: molecular analysis for diagnosis of X-linked hyper-IgM syndrome

CD40 ligand (CD40L) on activated T cells plays a crucial role for Ig heavy-chain class switching and the mutation of the gene for this ligand in the X-chromosome causes immunodeficiency with hyper-IgM (X-HIM). We isolated and characterized the human genomic clone for CD40 L to obtain information about the transcriptional regulatory regions of the gene and to develop a molecular diagnostic method for X-HIM patients. The genomic DNA isolated was over 12 kb long containing 5 exons that cover full sequence of mRNA for the ligand. DNA motif analysis based on transcription factor database revealed the presence of a GATA 1 box at around -265 bp. The typical TATA box, CAT site or GC rich region was not found in the 5' flanking region. However, two possible TATA like sequences were found at around -27 and -136 bp. Using the oligonucleotide primers corresponding to the introns, we performed a PCR-SSCP analysis of each exon from a patient with X-HIM syndrome and detected abnormality in exon 5. When sequenced, dinucleotide deletion in this exon was found in the patient and in one X allele of his mother as the only different sequence from that of the control gene. This procedure is simple and could be used for diagnosis of the X-HIM syndrome.

Evaluation of new medium with chromogenic substrates for members of the family Enterobacteriaceae in urine samples

A new medium containing 5-bromo-4-chloro-3-indolyl-beta-D-glucuronide cyclohexylammonium salt (Glu agar) for Escherichia coli and a new medium containing 5-bromo-3-indolyl-beta-D-galactoside (Gal agar) for beta-galactosidase-positive members of the family Enterobacteriaceae were compared with MacConkey agar in a diagnostic trial with 3,562 urine specimens. The isolation rates of E. coli and beta-galactosidase-positive Enterobacteriaceae were increased 8.4 and 19.5%, respectively. The sensitivities and specificities of Glu agar and Gal agar were 98.5 and 100% and 99.2 and 99.5%, respectively.

Direct antitumor effect of cepharanthin and combined effect with adriamycin against Ehrlich ascites tumor in mice

Direct antitumor effect of cepharanthin (CEP) and the combined effect with adriamycin (ADR), as well as the effect of CEP against body weight loss caused by treatment of ADR were evaluated using ICR mice bearing Ehrlich ascites tumor. Single administration of CEP reduced tumor growth compared to that of the untreated control, but not significantly. However, multiple administration of CEP reduced the tumor growth significantly compared to that of the untreated control (p < 0.001). Simultaneous administration of intratumoral CEP and intravenous ADR reduced the tumor growth significantly compared to that of ADR alone (p < 0.05). Further, CEP restored body weight loss caused by the treatment of ADR (p < 0.01). These findings indicate that the combined administration of CEP and ADR may be effective in cancer treatment.

Pathophysiology of dogs after 84% hepatectomy with emphasis on prostaglandin metabolites and the effect of a thromboxane A2 synthesis inhibitor and a prostaglandin I2 analog

The pathophysiological conditions following 84% hepatectomy were examined in terms of the changes in thromboxane A2 (TxA2) and prostaglandin I2 (PGI2) in a canine model. OKY-046, a TxA2 inhibitor, and OP-2507, a PGI2 analog, were administered to evaluate the possibility of extending hepatic resection. The 2-week survival rate following 84% hepatectomy significantly improved after the administration of OKY-046 and OP-2507, from 12.5% to 58.3% and 75.0%, respectively. Furthermore, OP-2507 significantly improved impaired hepatocyte and sinusoidal endothelial cell function after 84% hepatectomy, resulting in a satisfactory recovery to the preoperative levels. Within 24 h after 84% hepatectomy, the plasma levels of thromboxane B2 (TxB2) increased significantly, and the 6-keto-prostaglandin F1 alpha (6-KF) levels became slightly elevated. OKY-046 and OP-2507 decreased TxB2 and increased 6-KF in the plasma, resulting in the maintenance of sufficient blood flow in the portal vein and hepatic tissue and the mitigation of microcirculatory disorders. Moreover, the cytoprotective effects of the two drugs inhibited functional impairment of the residual liver. In conclusion, abnormal prostaglandin metabolites were produced after 84% hepatectomy, being involved in residual liver disorders. However, the administration of either an inhibitor of TxA2 synthesis or a PGI2 analog ameliorated the functional impairment of the residual liver, which suggests their potential value for extending the resectability of the liver from what is presently feasible.

An evaluation of renal tubular DNA laddering in response to oxygen deprivation and oxidant injury

It has recently been suggested that endonuclease activation and/or apoptosis, possibly triggered by oxidant stress, are important pathogenetic mechanisms in oxygen deprivation/reoxygenation-induced proximal tubular cell death. To explore this possibility, DNA "laddering," a characteristic feature of these processes, was sought in: (1) postischemic rat kidneys (25- or 40-min arterial clamping; 0, 1, 4, 8, 24, and 48 h and 6 days reflow); (2) posthypoxic isolate rat proximal tubular segments and (3) cultured human kidney proximal tubular cells (HK-2) subjected either to energy depletion plus Ca2+ overload (antimycin A plus 2-deoxyglucose plus Ca2+ ionophore A23187), or to H2O2-induced cell death. DNA was subsequently extracted, electrophoresed through agarose gels, and visualized with ethidium bromide or Southern blotting. To maximize ladder detection, DNA samples were also end-labeled with 32P dideoxyadenosine triphosphate with terminal deoxynucleotidyl transferase (tdt), followed by electrophoresis. None of the postischemic DNA samples demonstrated any laddering by either ethidium bromide staining or Southern analysis (apoptotic lymphocyte DNA was a positive control). However, trace laddering was apparent by the tat technique, commencing at 1 h of reflow, peaking at 24 h, and resolving slowly thereafter. This finding correlated with the morphologic expression of tubular necrosis, not apoptosis. Hypoxia/reoxygenation caused proximal tubular segment death (44 to 64%), and HK-2 cells were slowly killed by both the H2O2 and the energy depletion/Ca(2+)-loading protocols. However, neither protocol induced ethidium bromide- or tdt-detectable DNA laddering. It was concluded that: (1) minimal DNA laddering develops postischemia, and this change is reliably detected only by the tdt method; (2) it correlates with the morphologic expression of tubular necrosis, not apoptosis; and (3) in vitro oxidative- and energy depletion-mediated proximal tubular cell death can be dissociated from DNA ladder formation.

Human leukocyte antigen-class II-positive human corneal epithelial cells activate allogeneic T cells

PURPOSE

To achieve a better understanding of the mechanism of corneal immune diseases, including corneal allograft rejection, the authors examined the potential of human corneal epithelial (HCE) cells to activate allogeneic T lymphocytes.

METHODS

The mixed lymphocyte-HCE cell reaction (MLCER) was performed as follows: HCE cells from primary cultures, with or without treatment with interferon-gamma (IFN-gamma), were treated with mitomycin C and then mixed with peripheral blood lymphocytes (PBL) from normal volunteers. Triplicate cultures were incubated for 7 days. Interleukin-1-alpha (IL-1-alpha) was added to some cultures to examine its effect on MLCER: The lymphocyte responses were measured by 3H-thymidine uptake for the last 18 hours of incubation in MLCER:

RESULTS

IFN-gamma-treated, HLA-class-II-bearing HCE cells stimulated allogenic lymphocytes, whereas IFN-gamma nontreated, class-II-negative HCE cells did not. The stimulation by IFN-gamma-treated HCE cells was blocked by anti-HLA class II monoclonal antibody. In addition, exogenous IL-1-alpha reduced the lymphocyte response in MLCER: This effort was inhibited by indomethacin.

CONCLUSIONS

This study demonstrates that HLA-class-II-bearing HCE cells can activate allogeneic PBL by a major histocompatibility complex class II-dependent mechanism. In addition, HCE cells may regulate immune reactions, probably through prostaglandin production caused by IL-1.

The role of kinins and atrial natriuretic peptide on the renal effects of neutral endopeptidase inhibitor in rats

To further elucidate the natriuretic mechanisms of neutral endopeptidase 24.11 (NEP) inhibition, we employed a new specific NEP inhibitor, UK 73967 (UK), with or without a specific kinin receptor antagonist, Hoe 140 (Hoe), in Sprague-Dawley rats, and evaluated the renal NEP, kinins and plasma ANP simultaneously. There were no significant changes in urinary NEP, kinins, urine volume (UV) or urinary sodium excretion (UNaV) with vehicle treatment in anesthetized normotensive rats. Infused UK (10 mg/kg) significantly decreased NEP, and increased kinins, UV and UNaV. There was not a significant difference in plasma ANP between the vehicle and UK groups. Simultaneous administration of Hoe (20 nmol/kg) canceled the increases of UV and UNaV caused by UK. From these results, we conclude that inhibition of NEP may exaggerate the contribution of renal kinins to the renal water-sodium metabolism and overcome the contribution of ANP on that metabolism at least in normotensive rats.

[The correlation between the MICs deduced from Showa disk method and the MICs determined by micro-dilution method]

Disc diffusion technique is useful to routine drug susceptibility testing for bacteria in clinical laboratories because of the advantages on simplicity and cost. Kirby-Bauer (KB) method recommended by NCCLS is using widely as a standard method of disk diffusion test, and simply categorize microorganisms as being susceptible, moderately susceptible, intermediate or resistant to different antimicrobial agents by the use of break point. In the determination of breakpoints, the relationship between MICs and clinical results and pharmacokinetics parameters (Cmax, T1/2 and AUC) are significantly considered. However, there are variance of pharmacokinetics among a race, moreover, breakpoint is not yet established in Japan. In report to doctor from clinical laboratory, the MIC might be better than that by breakpoint since there are such problems of breakpoint. Showa disk was developed as mono-disk method being able to deduce MIC from the linear regression between MIC and zone diameter. Therefore, it is thought that Showa disk is one of valuable methods for the routine drug susceptibility testing for bacteria in Japan. There is one problem, which is that MIC deduced by Showa disk is based on the relationship with agar dilution method although the determination method of MIC is going to turn into micro-dilution method, so we compared the MICs deduced from zone diameter of Showa disk method with the MICs determined by broth micro-dilution method by using a challenge set of 110 gram-positive and gram-negative bacteria for 7 antimicrobial agents. The total agreement of MIC within 1-log2 dilution difference was 77% and the correlation coefficient was 0.929. As results, a good relationship was obtained except the results of tetracycline and ofloxacin for beta-lactamase non-producing H. influenzae, and ceftizoxime for E. coli, and K. pneumoniae.

[A case of sarcoidosis associated with severe cardiac conduction disturbances and unilateral pleural effusion]

A 23-year-old man was admitted to our hospital because of non-productive cough. Chest X-ray demonstrated bilateral hilar lymphadenopathy, bilateral infiltration shadows and right pleural effusion. ECG showed complete A-V block and sinus arrest. Transbronchial lung biopsy and pleural biopsy specimens showed non-necrotizing epithelioid cell granulomas. The patient was diagnosed as having sarcoidosis, and was treated with steroid and pacemaker. After steroid therapy, myocardial imaging with thallium-201 showed increase of uptake and the pleural effusion disappeared.

Gonadotropin releasing hormone (GnRH) neurons project to growth hormone and somatolactin cells in the steelhead trout

Analysis of gene expression using gonadotropin-releasing hormone (GnRH) antisense oligonucleotide confirmed by immunocytochemical localization the occurrence of GnRH neurons along the nervus terminalis in the steelhead trout (Oncorhynchus mykiss). Double-label immunocytochemistry revealed the distribution of mammalian (m), salmon (s) and chicken II (cII)-type GnRHs and various pituitary hormones. Both sGnRH and mGnRH appeared to be colocalized in the same cells of the nervus terminalis. Chicken GnRH II-immunoreactivity was found only in fibers and terminals. In the younger fish [73 and 186 days after fertilization (DAF)] GnRH neurons were seen rostral to the olfactory bulb. A novel GnRH ganglion, along the nervus terminalis, was found at the cribiform bone (gCB). A few non-immunoreactive rounded cells were seen among the GnRH neurons. A second smaller ganglion was seen at the most rostrally located part of the ventromedial olfactory bulb (gROB). In the older fish (850 DAF) GnRH neurons were also observed in the basal forebrain. A small group of neurons (2-3 cells), at the caudoventromedial border of the olfactory bulb, formed the ganglion terminale. Occasionally isolated GnRH-immunoreactive cells were seen at the base of the olfactory epithelium, along the ventromedial margins of the olfactory nerve. GnRH-immunoreactive and GnRH mRNA expressing neurons were absent from midbrain regions at the ages observed. GnRH-immunoreactive fibers were present only in older fish. The pattern of distribution of fibers that were immunoreactive to all three forms of GnRH was identical. Fibers were seen along the medial side of the olfactory nerve, throughout the brain and in the pituitary, associated with growth hormone and somatolactin cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium accumulation following middle cerebral artery occlusion in stroke-prone spontaneously hypertensive rats

Delayed neuronal damage in the ischemic region of the rat brain following middle cerebral artery (MCA) occlusion in stroke-prone spontaneously hypertensive rats was studied. The distribution of neuronal damage was determined by 45Ca autoradiography. Accumulation of 45Ca was observed in the corpus callosum and ipsilateral cerebral cortex immediately following MCA occlusion. After 3 days of occlusion, 45Ca had accumulated in the ipsilateral pyramidal tract, the ventral posterior nucleus of the thalamus, and the lateral portion of the striatum. Significant accumulation of 45Ca was observed in the same areas after 7 and 14 days of occlusion. Next the effect of MK-801 on accumulation of 45Ca after MCA occlusion was examined using the same technique. MK-801 (0.5-10 mg/kg i.v.) or saline was administered 15 min before MCA occlusion, and volumes of accumulation of 45Ca were calculated 1 week after ischemic insults. MK-801 significantly reduced 45Ca uptake in the cortex, striatum, and thalamus. Furthermore, there was a strong statistical correlation between the volume of accumulation of 45Ca in the cortex and that in the thalamus (r = 0.8974; p < 0.001; n = 25). We speculate that delayed neuronal damage in the corpus callosum, ipsilateral pyramidal tract, and thalamus may be caused by secondary neuronal degeneration. However, neuronal damage in the striatum, a segment not supplied by the MCA, may be related to excessive release of glutamate.