Expression of CD44 variant isoforms, CD44v3 and CD44v6, are associated with prognosis in nasopharyngeal carcinoma.

OBJECTIVE: The clinical and prognostic significance of CD44 variant isoform expression in nasopharyngeal carcinoma is not well known. This study aimed to clarify whether CD44 variant isoform expression serves as a prognostic factor in nasopharyngeal carcinoma. METHODS: Forty-two nasopharyngeal carcinoma patients, who underwent concurrent chemoradiotherapy as the initial treatment, were the subjects of investigation. Expression of CD44 variant isoforms, CD44v3, CD44v4, CD44v5, CD44v6 and CD44v7, in nasopharyngeal carcinoma was assessed in relation to concurrent chemoradiotherapy resistance and disease-specific survival of the patients. RESULTS AND CONCLUSION: The patients with CD44v6 high expression showed a clinically incomplete response to concurrent chemoradiotherapy at the primary site. The disease-specific survival rate was lower in patients with high expression of CD44v3 than in those with low expression. These results suggest that analysis of CD44v6 and CD44v3 expression is useful in estimating prognosis and determining effective treatment strategies in nasopharyngeal carcinoma.

Consecutive national surveys of ABO-incompatible blood transfusion in Japan.

BACKGROUND AND OBJECTIVES: Morbidity and mortality from ABO-incompatible transfusion persist as consequences of human error. Even so, insufficient attention has been given to improving transfusion safety within the hospital. MATERIALS AND METHODS: National surveys of ABO-incompatible blood transfusions were conducted by the Japanese Society of Blood Transfusion, with support from the Ministry of Health, Labor and Welfare. Surveys concluded in 2000 and 2005 analysed ABO-incompatible transfusion data from the previous 5 years (January 1995 to December 1999 and January 2000 to December 2004, respectively). The first survey targeted 777 hospitals and the second, 1355 hospitals. Data were collected through anonymous questionnaires. RESULTS: The first survey achieved a 77.4% response rate (578 of 777 hospitals). The second survey collected data from 251 more hospitals, but with a lower response rate (61.2%, or 829 of 1355 hospitals). The first survey analysed 166 incidents from 578 hospitals, vs. 60 incidents from 829 hospitals in the second survey. The main cause of ABO-incompatible transfusion was identification error between patient and blood product: 55% (91 of 166) in the first survey and 45% (27 of 60) in the second. Patient outcomes included nine preventable deaths from 1995 to 1999, and eight preventable deaths from 2000 to 2004. CONCLUSION: Misidentification at the bedside persists as the main cause of ABO-incompatible transfusion.

Immunohistochemical staining of cutaneous tumours with G-81, a monoclonal antibody to dermcidin.

BACKGROUND: Recently, the novel antimicrobial peptide named dermcidin (DCD) was reported in human eccrine sweat glands. OBJECTIVES: We investigated the expression of DCD in a variety of cutaneous tumours in order to assess the usefulness of the monoclonal antibody (G-81), which recognizes a fragment of DCD. PATIENTS/METHODS: We studied the immunoreactivity of the G-81 antibody on 197 cutaneous tumours. RESULTS: A total of 13 of 26 cutaneous mixed tumours showed substantial immunoreactivity. In contrast all the following cases were completely unreactive: (i) epithelial tumours (seborrhoeic keratosis, squamous cell carcinoma, Bowen's disease, actinic keratosis, genital Paget's disease); (ii) follicular tumours (basal cell carcinoma, trichilemmoma, trichoepithelioma, trichoblastoma, keratoacanthoma, proliferating trichilemmal tumour, pilomatricoma); (iii) melanocytic tumours (malignant melanoma, naevus cell naevus, Spitz naevus, blue naevus); (iv) neural tumours (schwannoma, neurofibroma, Merkel cell neoplasm); (v) mesenchymal tumours (soft fibroma, dermatofibroma, dermatofibrosarcoma protuberans, vascular leiomyoma, leiomyosarcoma, lipoma, juvenile xanthogranuloma, angiomyoma); and (vi) other sweat gland tumours (poroid neoplasms, syringoma, cylindroma, clear cell hidradenoma, spiradenoma, syringoid eccrine carcinoma, mucinous carcinoma, apocrine cystadenoma, syringocystadenoma papilliferum, apocrine adenocarcinoma). Twenty-six cutaneous mixed tumours were considered from histopathological findings to be the apocrine type, but 13 of 26 mixed tumours contained some DCD-immunopositive cells that possibly differentiate into eccrine secretory glands. CONCLUSIONS: We found the expression of DCD in tubular structures of 50% of cutaneous mixed tumours with apocrine differentiation. These results suggest that a number of cutaneous mixed tumours show both eccrine and apocrine differentiation in the same neoplasm.

Ride quality evaluation of an actively-controlled stretcher for an ambulance.

This study considers the subjective evaluation of ride quality during ambulance transportation using an actively-controlled stretcher (ACS). The ride quality of a conventional stretcher and an assistant driver's seat is also compared. Braking during ambulance transportation generates negative foot-to-head acceleration in patients and causes blood pressure to rise in the patient's head. The ACS absorbs the foot-to-head acceleration by changing the angle of the stretcher, thus reducing the blood pressure variation. However, the ride quality of the ACS should be investigated further because the movement of the ACS may cause motion sickness and nausea. Experiments of ambulance transportation, including rapid acceleration and deceleration, are performed to evaluate the effect of differences in posture of the transported subject on the ride quality; the semantic differential method and factor analysis are used in the investigations. Subjects are transported using a conventional stretcher with head forward, a conventional stretcher with head backward, the ACS, and an assistant driver's seat for comparison with transportation using a stretcher. Experimental results show that the ACS gives the most comfortable transportation when using a stretcher. Moreover, the reduction of the negative foot-to-head acceleration at frequencies below 0.2 Hz and the small variation of the foot-to-head acceleration result in more comfortable transportation. Conventional transportation with the head forward causes the worst transportation, although the characteristics of the vibration of the conventional stretcher seem to be superior to that of the ACS.

Efficacy of common antiseptics against multidrug-resistant Mycobacterium tuberculosis.

OBJECTIVES: The incidence of infections caused by multidrug-resistant strains of Mycobacterium tuberculosis (MDR-TB) has been increasing. Antiseptics are frequently used to prevent mycobacterial infection. The aim of this study was to determine those antiseptics that are useful against MDR-TB. DESIGN: We evaluated bactericidal activity against clinical isolates of MDR-TB in vitro. METHOD: Thirteen strains of MDR-TB were tested against povidone-iodine (PVP-I), cresol, akyldiaminoethyl glycine hydrocloride (AEG), and glutaraldehyde. After bacilli were exposed to the antiseptic solution with 2% human serum, the disinfectant was inactivated by addition of neutraliser. RESULTS: PVP-1 at a final concentration of 0.2% killed all of the strains within 120 seconds, and PVP-I at 0.1% killed 99.9% or more bacilli within 60 seconds. Most strains were killed after exposure to 0.5% cresol at 300 seconds and to 1.0% cresol at 60 seconds; 3.0% cresol killed all bacilli within 120 seconds, while 0.1%, 0.2%, and 0.5% AEG all required 60 minutes to kill 99.9% or more of the bacilli; 2.0% glutaraldehyde required 10 minutes to kill all bacilli. CONCLUSION: The bactericidal activities of antiseptics for MDR-TB were similar to those for drug-sensitive M. tuberculosis strains. PVP-I would be a useful antiseptic against MDR-TB. The bactericidal activities of glutaraldehyde are effective against MDR-TB as an antiseptic for medical equipment.

Bactericidal activities of commonly used antiseptics against multidrug-resistant mycobacterium tuberculosis.

Seventeen clinical isolates of Mycobacterium tuberculosis were selected in order to study the bactericidal activities against drug-resistant M. tuberculosis. The effects of different antiseptics against multidrug-resistant M. tuberculosis (MDR-TB) were examined. Each of the test strains was cultured on the surface of an agar slant containing Löwenstein-Jensen medium. 0.05 ml of the bacillary suspension was poured into a test tube, and 0.45 ml of various antiseptics was added. After the bacilli had been exposed to the antiseptic solution with 2% human serum for various periods of incubation time, the antiseptic was inactivated by addition of 0.45 ml neutralizer, a mixture containing 10% Tween 80, 3% soybean lecithin and 0.5% sodium thiosulfate. As the results, povidone-iodine (PVP-I) at a concentration of 0.2% killed 99.9% or more of all strains tested within 30 s. All of the strains tested with PVP-I were killed almost completely within 60 s. There was no difference in bactericidal activities of PVP-I between standard strain H37Rv and MDR-TB. 99.9% or more of all strains tested were killed after exposure to 1.0% cresol for 60 s. In the case of cresol however, the exposure time of 30 s was not enough to get satisfactory effects. 2.0% glutaraldehyde needed 5 min to kill 99.99% or more of the bacilli tested, and 0.2% alkyldiaminoethylglycine hydrochloride required 60 min to do so. The results of bactericidal activities of common antiseptics against MDR-TB were similar to those against H37Rv. We conclude that the commercially available PVP-I product is a useful antiseptic against MDR-TB similar to other M. tuberculosis.

Spectral luminous efficiency as a function of age.

Spectral luminous efficiency function for a 2-deg field at a photopic level (100 Td) was measured for 91 observers by flicker photometry (FP) and for 97 observers by direct brightness matching (DBM), to find age-related change in the efficiency function as well as to obtain a reliable data set to be used in photometry. Observers ranged in age from 11 to 78 years. A gradual reduction of luminous efficiency with age was observed for both functions by FP and by DBM in the short-wave region, which was expected because of the age-related increase of optical density of eye lens. A similar age-related reduction of efficiency was observed in the long-wave region for the function obtained by DBM; this reduction was regarded as being due to reduced chromatic contribution to brightness with age. Principal components analysis on the spectral efficiency data and an analysis of the efficiency difference between the data obtained by DBM and FP confirmed this conclusion. Assuming a log-linear change in efficiency with age for any wavelength throughout the life span, spectral luminous efficiency function at any age was derived for photometric use.

Novel low molecular weight spirodiketopiperazine derivatives potently inhibit R5 HIV-1 infection through their antagonistic effects on CCR5.

Novel low molecular weight spirodiketopiperazine derivatives which potently inhibit R5 human immunodeficiency virus type 1 (HIV-1) infection through their antagonistic effects on CCR5 were identified. One such compound E913 (M(r) 484) specifically blocked the binding of macrophage inflammatory protein-1alpha (MIP-1alpha) to CCR5 (IC(50) 0.002 microm) and MIP-1alpha-elicited cellular Ca(2+) mobilization (IC(50) approximately 0.02 microm). E913 potently inhibited the replication of laboratory and primary R5 HIV-1 strains as well as various multidrug-resistant monocyte/macrophage tropic (R5) HIV-1 at IC(50) values of 0.03 to 0.06 microm. E913 was inactive against T cell tropic (X4) HIV-1; however, when combined with a CXCR4 antagonist AMD-3100, E913 potently and synergistically inhibited the replication of dualtropic HIV-1 and a 50:50 mixture of R5 and X4 HIV-1. Antagonism in anti-HIV-1 activity was not seen when E913 was combined with the reverse transcriptase inhibitor zidovudine or protease inhibitors. E913 proved to compete with the binding of antibodies to CCR5 which recognize the C-terminal half of the second extracellular loop (ECL2B) of CCR5. E913 and its analogs are acid-resistant and orally bioavailable in rodents. These data warrant that spirodiketopiperazine derivatives be further developed as potential therapeutics for HIV-1 infection.

Design and synthesis of a highly selective EP2-receptor agonist.

EP2-receptor selective agonist 3 was identified by the structural hybridization of butaprost 1a and PGE(2) 2a. Based on this information, a chemically more stabilized 4 was discovered as another highly selective EP2-receptor agonist, iv administration of which to anesthetized rats suppressed uterine motility, while PGE(2) 2a stimulated uterine motility.

The functional interactions between CD98, beta1-integrins, and CD147 in the induction of U937 homotypic aggregation.

CD98 is expressed on both hematopoietic and nonhematopoietic cells and has been implicated in a variety of different aspects of cell physiology and immunobiology. In this study, the functional interactions between CD98 and other adhesion molecules on the surface of the promonocyte line U937 are examined by means of a quantitative assay of cell aggregation. Several of the CD98 antibodies induced homotypic aggregation of these cells without affecting cellular viability or growth. Aggregation induced by CD98 antibodies could be distinguished from that induced by beta1-integrin (CD29) ligation by lack of sensitivity to EDTA and by increased sensitivity to deoxyglucose. Aggregation induced via CD98 and CD29 could also be distinguished by the pattern of protein tyrosine phosphorylation induced. Some CD29 antibodies partially inhibited CD98-induced aggregation, and these antibodies were neither agonistic for aggregation nor inhibitors of beta1-integrin binding to substrates. Conversely, some CD98 antibodies were potent inhibitors of CD29-induced aggregation. Antibodies to beta2 integrins also partially inhibited CD98-induced aggregation. Unexpectedly, 2 antibodies to CD147, an immunoglobulin superfamily member whose function has remained unclear, were also potent inhibitors of both the aggregation and the protein tyrosine phosphorylation induced via CD98 ligation. The results of this study support a central role for CD98 within a multimolecular unit that regulates cell aggregation.

[Clinical laboratory data and reference intervals standardized in Fukuoka].

In Fukuoka whose population is approximately five million inhabitants, surveys on the accuracy of laboratory data have been performed by the Fukuoka Prefecture Medical Association for the last 30 years. We have been attempting to evaluate the data for routine use since 1988, and it has become possible to share laboratory data between all institutions in Fukuoka prefectures. As a result, reference intervals for 23 clinical chemistry analytes were established in 1995, to which were added in 1996 five serum protein constituents that have been utilized for clinical examinations. Methods for documentations and monitorings the data obtained in the prefecture were also established, standardization of the above analytes extended to 97% of the institutions in the prefecture. Results for 14 of the 23 clinical chemistry analytes have become highly reliable and clinically useful as differences between institutions in terms of results have narrowed. Standardization of other analytes is now in progress.

Response of the stroke volume and blood pressure of young patients with nonobstructive hypertrophic cardiomyopathy to exercise.

Stroke volume (SV), cardiac output (CO) and systolic blood pressure (SBP) were measured during maximal symptom-limited bicycle exercise testing in 13 young patients (age, 11-26 years) with nonobstructive hypertrophic cardiomyopathy (HCM). SV was measured by impedance plethysmocardiography; %SVend, %COend, and %SBPend represent the ratio of the value at termination of the exercise to the respective value at rest. In all patients of HCM-I (the Cardiac Event Group, 3 patients) and 3 of HCM-II (the Non-Cardiac Event Group, 10 patients), the %SVend was less than 100%. The %SVend of HCM-I was significantly lower than the respective values of the HCM-II and Control groups. The %COend values of the HCM-I and HCM-II groups were each significantly lower than that of the Control. The %SBPend values of the HCM-I and HCM-II groups were each significantly lower than that of the Control. Among the HCM patients, the %SVend value was positively correlated with the %SBPend value. The patients who had more severe HCM had poorer exercise-induced increases in SV and SBP. These results suggest that sudden cardiac death in young HCM patients is associated with inhibition of the increase in SV upon exercise.

Activation of purified cardiac ryanodine receptors by dihydropyridine agonists.

Prior observations have raised the possibility that dihydropyridine (DHP) agonists directly affect the sarcoplasmic reticulum (SR) cardiac Ca(2+) release channel [i.e., ryanodine receptor (RyR)]. In single-channel recordings of purified canine cardiac RyR, both DHP agonists (-)-BAY K 8644 and (+)-SDZ202-791 increased the open probability of the RyR when added to the cytoplasmic face of the channel. Importantly, the DHP antagonists nifedipine and (-)-SDZ202-791 had no competitive blocking effects either alone or after channel activation with agonist. Thus there is a stereospecific effect of SDZ202-791, such that the agonist activates the channel, whereas the antagonist has little effect on channel activity. Further experiments showed that DHP agonists changed RyR activation by suppressing Ca(2+)-induced inactivation of the channel. We concluded that DHP agonists can also influence RyR single-channel activity directly at a unique allosteric site located on the cytoplasmic face of the channel. Similar results were obtained in human purified cardiac RyR. An implication of these data is that RyR activation by DHP agonists is likely to cause a loss of Ca(2+) from the SR and to contribute to the negative inotropic effects of these agents reported by other investigators. Our results support this notion that the negative inotropic effects of DHP agonists result in part from direct alteration in the activity of RyRs.

Beta,gamma-methylene ATP-induced cAMP formation in C6Bu-1 cells: involvement of local metabolism and subsequent stimulation of adenosine A2B receptor.

The mechanism underlying beta,gamma-methylene ATP (beta,gamma-MeATP)-induced cAMP elevation was investigated in rat glioma C6Bu-1 cells. Beta,gamma-MeATP increased forskolin-stimulated cAMP formation in a manner sensitive to both the P1 antagonist xanthine amine congener (XAC) and the P2 antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS). Adenosine deaminase (ADA; 1 U/mL), which abolished the adenosine-induced response, did not eliminate the beta,gamma-MeATP-induced response. However, combination of ADA with alpha,beta-methylene ADP (alpha,beta-MeADP), an ecto-5'-nucleotidase inhibitor, blocked the beta,gamma-MeATP-induced response. AMP, the substrate for ecto-5'-nucleotidase, also induced cAMP formation in a manner sensitive to XAC and alpha,beta-MeADP inhibition. However, the AMP-induced response was not blocked by PPADS. HPLC analyses revealed that adenosine was generated from beta,gamma-MeATP and AMP. In addition, alpha,beta-MeADP inhibited the conversion of beta,gamma-MeATP and AMP to adenosine, whereas PPADS blocked adenosine formation from beta,gamma-MeATP but not from AMP. [3H]Adenosine generated from [3H]AMP was preserved on the cell surface environment even in the presence of ADA. The mRNAs for ecto-phosphodiesterase/pyrophosphatase 1 (EC 3.1.4.1), ecto-5'-nucleotidase (EC 3.1.3.5) and adenosine A2B receptor were detected by RT-PCR. These results suggest that C6Bu-1 cells possess ecto-enzymes converting beta,gamma-MeATP to adenosine, and the locally accumulated adenosine in this mechanism efficiently stimulates A2B receptors in a manner resistant to exogenous ADA.

Soluble Fas ligand and soluble Fas in ocular fluid of patients with uveitis.

AIMS: To investigate the presence of soluble Fas ligand (sFasL) and soluble Fas (sFas) in ocular fluid of patients with uveitis. METHODS: Samples of aqueous humour (AH, n=17), vitreous fluid (n=9), and serum (n=60) were collected from patients with uveitis which included Behçet's disease, Vogt-Koyanagi-Harada disease, sarcoidosis, human T lymphotropic virus type 1 (HTLV-I) uveitis, sympathetic ophthalmia, HLA-B27 associated acute anterior uveitis, and ocular toxoplasmosis. The AH of patients with age related cataract without uveitis obtained during cataract surgery was used as controls (n=20). The amounts of sFasL and sFas were measured by enzyme linked immunosorbent assay. RESULTS: Significant amounts of sFasL were detected in AH of patients with age related cataract (non-uveitis group). sFasL was also detected in AH of patients with uveitis, though the amounts were slightly lower than those in the non-uveitis group. On the other hand, the levels of sFas in AH of patients with uveitis were significantly higher than those in controls. As for the disease activity, the levels of sFasL and sFas in the vitreous fluid of patients with active uveitis were significantly higher than those in inactive uveitis. sFasL in the serum of healthy donors and patients with uveitis was below detectable levels, except for patients with HTLV-I uveitis who had significant amounts of sFasL in the serum. The levels of sFas in the serum of patients with Behçet's disease, sarcoidosis, and HTLV-I uveitis were significantly higher than those of healthy donors. CONCLUSIONS: sFasL is present in the AH of non-uveitic eyes with age related cataract. Intraocular levels of sFasL and sFas are significantly increased in uveitis, particularly in active uveitis. These data suggest that intraocular sFasL and sFas may have a regulatory role in uveitis.

Hormonal regulation of sodium/sulfate co-transport in renal epithelial cells.

Serum sulfate concentrations are elevated in infants, young children, and pregnant women due, at least in part, to increased renal sulfate reabsorption. Little is known about the effects of hormones, particularly those involved in growth, development, and pregnancy, on renal sulfate reabsorption. The objective of this investigation was to examine the effects of growth hormone (GH), insulin-like growth factor 1 (IGF-1), progesterone (PG), and 17beta-estradiol (EST) on renal sodium/sulfate co-transport. 35S-sulfate uptake was determined in Madin-Darby canine kidney (MDCK)/NaSi-1 cells (MDCK cells that have been stably transfected with rat sodium/sulfate co-transporter (NaSi-1) cDNA) and in opossum kidney (OK) cells. NaSi-1 mRNA was determined by RT-PCR and protein levels by ELISA. GH (0.1 nM) significantly increased the sodium/sulfate co-transport in MDCK/NaSi-1 cells up to 35%. IGF-1 induced a concentration-related stimulation of the sodium/sulfate co-transport with a maximal response observed at 1000 nM (59% increase). Sodium-dependent sulfate uptake was significantly increased when cells were preincubated with 10 nM PG, 10 nM EST, or 10 nM PG/10 nM EST up to 41%, 46%, or 39%, respectively. OK cells exhibited endogenous sodium-dependent sulfate transport; significantly increased sodium/sulfate co-transport was also observed in OK cells that were preincubated with GH, IGF-1, and PG/EST, although not with EST alone. The NaSi-1 mRNA and NaSi-1 protein levels were significantly increased in MDCK/NaSi-1 cells treated with 0.1 nM GH, 100 nM IGF-1, 10 nM PG, and/or 10 nM EST compared with control. These results suggest that the increased renal sulfate reabsorption that occurs in neonates, young and pregnant humans, and animals could be mediated by the increased steady-state levels of NaSi-1 mRNA produced by the higher plasma concentrations of GH, IGF-1, or PG/EST.

HIV-Nef enhances interleukin-2 production and phosphatidylinositol 3-kinase activity in a human T cell line.

OBJECTIVE: The Nef protein has a major influence on disease pathogenesis in HIV-infected individuals. The objective of the present study was to examine the effects of Nef on T lymphocyte activation and associated signalling events. DESIGN: A recombinant vaccinia expression system was used to express Nef in a human T cell line. Stimulation of these cells with anti-CD28 antibody, and either phorbol 12-myristate 13-acetate (PMA) or anti-CD3, activates signal transduction pathways and results in IL-2 production and IL-2 receptor alpha-chain (CD25) expression. Cellular responses were examined in cells expressing either Nef or an irrelevant control protein. METHODS: Activation of signalling was assessed by immunoblot analysis, or by in-vitro phosphatidylinositol 3-kinase (PI3K) assays. IL-2 production was measured by enzyme-linked immunosorbent assay, and CD25 cell surface expression was examined using flow cytometry. RESULTS: Infection of cells with recombinant vaccinia expressing HIV-nef resulted in a marked increase in the production of IL-2 when cells were activated. The enhanced IL-2 response was accompanied by an increase in the level of PI3K activity. IL-2 production remained sensitive to inhibition with the PI3K competitive inhibitor Ly294002, and to the fungal macrolide, rapamycin. In contrast, CD25 expression was not affected, and there were no measurable changes to nuclear factor kappaB (NFkappaB) activation pathways. CONCLUSION: Enhanced IL-2 production in stimulated T cells expressing HIV-Nef is associated with increased activation of PI3K-dependent signalling pathways. The results support a model in which Nef affects HIV disease progression by distorting T cell responses.

Molecular mechanisms of renal sulfate regulation.

Inorganic sulfate is an important physiological anion that is a required cofactor for sulfate conjugation reactions of both endogenous and exogenous compounds. It is necessary for the detoxification of xenobiotics and endogenous compounds (catecholamines, steroids, bile acids), for the synthesis of structural components of membranes and tissues (sulfated glycosaminoglycans), and for the biologic activity of endogenous compounds (heparin and cholecystokinin). Inorganic sulfate homeostasis is largely maintained by reabsorption in the renal proximal tubule. Sodium-dependent sulfate cotransport in the brush border membrane is of primary importance in the regulation of plasma inorganic sulfate concentrations. Altered renal reabsorption of sulfate has been observed under different physiological (age, pregnancy, low dietary intake), pathological (hypothyroidism, trace metal excess), and pharmacological conditions (treatment with nonsteroidal antiinflammatory agents). The recent identification of the sulfate transporter genes has allowed the investigation of the molecular mechanisms of altered sulfate transport. Although the regulation of sulfate homeostasis is not fully understood, recent investigations have explored the cellular mechanisms of some of these alterations. In this review, the physiological importance of inorganic sulfate, the availability of this anion, and the regulation of sulfate homeostasis are discussed.

Glucocorticoid-induced alterations of renal sulfate transport.

Glucocorticoid administration decreases renal sodium/phosphate cotransport in the proximal tubule due to a down-regulation of the sodium/phosphate cotransporter but has no effect on the sodium-dependent transport of glucose or proline. The objectives of the present investigation were to determine the effects of the glucocorticoid methylprednisolone (MPL) on 1) inorganic sulfate renal clearance in rats in vivo, 2) sodium/sulfate cotransport in kidney cortex membrane vesicles, and 3) the cellular mechanism of the MPL-induced alterations in sulfate renal transport. Male adrenalectomized Wistar rats received an i.v. dose of 50 mg/kg MPL or the vehicle. Urine samples were collected for 12 h after the administration of MPL, and blood samples were collected at the midpoint of the urine collection. Other animals were sacrificed at 4, 6, and 12 h after MPL administration, and the kidney cortex was removed for RNA or membrane preparations. Kidney cortex sodium/sulfate cotransporter (NaSi-1) mRNA levels were determined by reverse transcription-polymerase chain reaction and NaSi-1 protein levels were determined by enzyme-linked immunosorbent assay. The urinary excretion rate and renal clearance of sulfate were significantly increased in MPL-treated animals (144.0 +/- 27.0 versus 65.3 +/- 21.3 micromol/12 h/kg and 0.208 +/- 0.038 versus 0. 078 +/- 0.025 ml/min/kg, mean +/- S.E., n = 9-12 in treated versus control). The V(max) value for sodium-dependent sulfate transport in brush border membrane vesicles (representing reabsorption in the proximal tubules) was significantly decreased in MPL-treated animals compared with controls (0.68 +/- 0.07 versus 0.88 +/- 0.05 nmol/mg of protein/10 s, mean +/- S.E.). There was no change in the K(m) value for sodium/sulfate cotransport in brush-border membrane and no change in sulfate/anion exchange in basolateral membrane vesicles. Membrane fluidity in brush border membrane and basolateral membrane vesicles, determined by the fluorescence polarization of 1, 6-diphenyl-1,3,5-hexatriene was unaltered by MPL treatment. NaSi-1 mRNA levels were significantly decreased at 4 and 6 h, but not 12 h, after MPL administration, whereas NaSi-1 protein expression was significantly decreased at 4, 6, and 12 h. Therefore, MPL treatment increases the renal clearance of inorganic sulfate, at least in part, due to down-regulation of NaSi-1 mRNA and protein expression in the kidney.

Novel molecular mechanisms of dendritic cell-induced T cell activation.

In this study we have re-examined the molecular mechanisms involved in activation of T cells by dendritic cells (DC). Human peripheral blood DC (PBDC) were derived by 2 h adhesion followed by 7 day culture in a combination of granulocyte macrophage colony stimulating factor and IL-4, and depletion of residual T and B cells. These PBDC were used to induce autologous T cell proliferation in a CD3-dependent response, and antibodies against CD11a/18 and CD86 were used as control inhibitors of accessory function. Antibodies against five of the cell surface molecules that we have recently identified on the surface of DC, CD13, CD87, CD98, CD147 and CD148, and an antibody which recognizes a molecule that has not as yet been identified, all inhibited the CD3-induced T cell proliferation. These findings were observed not only when antibodies were present throughout the culture, but also when they were prepulsed on to the surface of the DC, suggesting the inhibition was mediated via the antigen-presenting cells rather than the T cell. The same set of antibodies also inhibited an allospecific mixed lymphocyte reaction, confirming that the inhibitory effect was not dependent on the use of a CD3 antibody as the stimulating agent. All the antibodies of known specificity inhibited both CD4 and CD8 T cells equally. Unlike CD87, CD98 and CD147 antibodies, which inhibited activation of both CD45RA (naive) T cells and CD45RO (memory) T cells, CD13 and CD148 appeared to be involved in activation of naive cells only. The molecules identified in this study have not previously been demonstrated to play a role as accessory molecules on DC, the cells that are pivotal for immune induction. Therefore they may provide new potential targets for modulation of the immune response at the APC level.