Possible role of oestrogen in pubertal increase of Kiss1/kisspeptin expression in discrete hypothalamic areas of female rats.

Kisspeptin, a peptide encoded by the Kiss1 gene, has been considered as a potential candidate for a factor triggering the onset of puberty, and its expression in the hypothalamus was found to increase during peripubertal period in rodent models. The present study aimed to clarify the oestrogenic regulation of peripubertal changes in Kiss1 mRNA expression in the anteroventral periventricular nucleus (AVPV) and hypothalamic arcuate nucleus (ARC), and to determine which population of kisspeptin neurones shows a change in kisspeptin expression parallel to that in luteinising hormone (LH) pulses at the peripubertal period. Quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry revealed an apparent increase in the ARC Kiss1 mRNA expression and kisspeptin immunoreactivity around the time of vaginal opening in intact female rats. The AVPV Kiss1 mRNA levels also increased at day 26, but decreased at day 31, and then increased at day 36/41. In ovariectomised (OVX) rats, ARC Kiss1 mRNA expression did not show peripubertal changes and was kept at a high level throughout peripubertal periods. Apparent LH pulses were found in these prepubertal OVX rats. Oestradiol replacement suppressed ARC Kiss1 mRNA expression in OVX prepubertal rats, but not in adults. Similarly, LH pulses were suppressed by oestradiol in the prepubertal period (days 21 and 26), but regular pulses were found in adulthood. The present study suggests that a pubertal increase of Kiss1/kisspeptin expression both in the ARC and AVPV is involved in the onset of puberty. These results also suggest that both LH pulses and ARC Kiss1 expression are more negatively regulated by oestrogen in prepubertal female rats compared to adult rats.

Increased distribution of carboplatin, an anti-cancer agent, to rat brains with the aid of hyperbaric oxygenation.

1. The distribution of an anti-cancer agent carboplatin to brains was investigated in combination with hyperbaric oxygenation treatment in rats. 2. After intravenous administration of carboplatin (30 mg kg(-1)) to male Wistar rats, elimination curves of plasma drug concentrations plotted against a time of 45 min were not different with or without hyperbaric oxygenation (at 0.20-0.25 MPa for last 20 min) treatments. 3. Carboplatin concentrations of livers, lungs and kidneys in each group were similar at the endpoint of hyperbaric oxygenation treatment. 4. Under these atmosphere conditions (at 0.10 MPa), carboplatin concentration was at an undetectable level in rat brains (<0.1 microg g(-1) tissue, n = 6). On the contrary, carboplatin was detected in all brains tested at the levels of 0.5 +/- 0.3 microg g(-1) tissue (mean and standard deviation (SD), n = 6), 0.8 +/- 0.5 microg g(-1) tissue, and 0.4 +/- 0.2 microg g(-1) tissue in combination with hyperbaric oxygenation at 0.20, 0.22, and 0.25 MPa, respectively, at the endpoint of hyperbaric oxygenation treatment. 5. The results suggest that carboplatin could be uptaken into rat brains at the detectable levels by the aid of hyperbaric oxygenation, consistently with the reported findings of enhanced transendothelial permeability and improved clinical efficacy of carboplatin combined hyperbaric oxygenation therapy.

Increased transendothelial permeability of anti-cancer agent carboplatin with the aid of hyperbaric oxygenation.

1. The objective was to investigate the transport of an anticancer agent carboplatin across the blood-brain barrier in combination with hyperbaric oxygenation treatment. An in vitro well-validated model of bovine brain capillary endothelial cells was used. 2. A transendothelial transport of doxorubicin, a known P-glycoprotein substrate, was enhanced 1.5-fold by verapamil for 2-h incubation at 37 degrees C. A transendothelial permeability coefficient of carboplatin (1.29 x 10(-3)cm min-1) was also increased 1.8-fold by verapamil. 3. Under the hyperbaric oxygenation conditions (at 0.2 MPa for the first 10 min), the transendothelial transport for 2 h of doxorubicin and carboplatin were increased 1.3- to 1.8-fold by hyperbaric oxygenation, like the suppressive effects of verapamil on P-gp function, without increase of the transport of lucifer yellow, a non P-glycoprotein substrate. 4. Combination of hyperbaric oxygenation treatment and verapamil could not further increase the permeability coefficients of these drugs that were already enhanced by either treatment, implying the P-glycoprotein-mediated carboplatin efflux transport similarly as doxorubicin. 5. Together with our reported high efficacy of carboplatin combined with hyperbaric oxygenation therapy on brain tumours, the present results suggest that carboplatin could be transported by P-glycoprotein, but that this efflux mechanism would be reduced by the hyperbaric oxygenation with the consequences of clinical efficacy.

Attenuation by dietary taurine of dextran sulfate sodium-induced colitis in mice and of THP-1-induced damage to intestinal Caco-2 cell monolayers.

The effects of dietary taurine on the experimental colitis induced by dextran sulfate sodium (DSS) in mice were evaluated. C57BL/6 female mice were given 3% DSS in drinking water for 5 d to induce acute colitis. Taurine at 2% was added to the drinking water 5 d before and during the DSS-treatment to investigate its preventive effect. Taurine supplementation significantly attenuated the weight decrease, diarrhea severity, colon shortening, and the increase in the colonic tissue myeloperoxidase activity induced by DSS. Taurine also significantly inhibited the increase in the expression of a pro-inflammatory chemokine, macrophage inflammatory protein 2 (MIP-2), but not of interleukin (IL)-1beta or tumor necrosis factor (TNF)-alpha mRNA. Furthermore, taurine significantly protected the intestinal Caco-2 cell monolayers from the damage by macrophage-like THP-1 cells in an in vitro coculture system. These results suggest that taurine prevented DSS-induced colitis partly in association with (1) its inhibitory effects on the secretion of MIP-2 from the intestinal epithelial cells and on the infiltration of such inflammatory cells as neutrophils and (2) its cytoprotective functions on the epithelial barrier from the direct toxicity of DSS and from the inflammatory cell-induced injury.

Anti-ulcerogenic activity of the aerial parts of Lithraea molleoides.

The hydro-alcoholic extract of the aerial parts of Lithraea molleoides, given orally at a dose of 1000 mg/kg, showed significant anti-ulcerogenic activity on ulcer induced by indomethacin and absolute alcohol in rats.

Chemical composition and antimicrobial activity of the essential oil of Cordiaverbenacea D.C.

Cordiaverbenacea D.C. (Boraginaceae) is found along the coastal regions of Brazil, from the Amazon basin to the southernmost state of Rio Grande do Sul. The aerial parts of this plant have been used in folk medicine since colonial times for their anti-rheumatic, anti-inflammatory, analgesic and healing properties. The objectives of this study were: the extraction of the essential oil of the aerial parts of this species and quantification of the yield thereof; the identification and quantification of the principal components of the essential oil; and the determination of its antimicrobial activity by plate diffusion method. The yield of essential oil was 0.19% (v/w) in relation to the fresh flowering aerial parts and 0.23% (v/w) of the leaves. The main constituents of the essential oil, identified by gas chromatography/mass spectrometry (GC/MS), were alpha-pinene (29.69%), trans-caryophyllene (25.27%) and aloaromadendrene (9.99%). The Gram-positive bacteria and yeast tested were sensitive to the essential oil of Cordiaverbenacea D.C., but most of the Gram-negative bacteria were resistant.

Polymorphisms in ADAM33 are associated with allergic rhinitis due to Japanese cedar pollen.

BACKGROUND: A recent report provided evidence that a disintegrin and metalloprotease domain 33 (ADAM33), a member of the ADAM family, is a novel susceptibility gene in asthma linked to bronchial hyper-responsiveness. However, there has been no investigation of the genetic role of ADAM33 variants in nasal allergy. OBJECTIVE: The purpose of this study was to test the association between ADAM33 polymorphisms and Japanese cedar pollinosis (JCPsis), a most common seasonal allergic rhinitis in Japan. METHODS: We conducted a case-control association study among a Japanese population, involving 95 adult individuals with JCPsis and 95 normal healthy controls. A total of 22 single-nucleotide polymorphisms (SNPs) in ADAM33 were genotyped using PCR-based molecular methods. RESULTS: Six SNPs of ADAM33 gene, three in introns (7575G/A, 9073G/A and 12540C/T) and three in the coding region (10918G/C, 12433T/C and 12462C/T), were strongly associated with JCPsis (P = 0.0002-0.022 for absolute allele frequencies) and most of the SNPs were in linkage disequilibrium with each other. A higher frequency of the common alleles of these SNPs was noted for the subjects with JCPsis in comparison with healthy controls. We also identified a haplotype associated with the disease susceptibility. In addition, associations were found between ADAM33 polymorphisms and various cedar pollinosis phenotypes including clinical severity, eosinophil counts in nasal secretion and allergen-specific IgE levels in sera, but not total serum IgE levels. CONCLUSION: These results indicate that polymorphisms in the ADAM33 gene are associated with susceptibility to allergic rhinitis due to Japanese cedar pollen, but the functional relationship still needs clarification.

Effect of alumina femoral heads on polyethylene wear in cemented total hip arthroplasty. Old versus current alumina.

We examined the behaviour of alumina ceramic heads in 156 cemented total hip arthroplasties, at a minimum follow-up of eight years. They were divided into three groups according to the size of the femoral head; 22, 26, and 28 mm. We measured polyethylene wear radiologically using a computer-aided technique. The linear wear rate of polyethylene sockets for the 28 mm heads was high (0.156 mm/year), whereas those for the 22 and 26 mm heads were relatively low (0.090 and 0.098 mm/year, respectively). Moreover, the surface roughness data of retrieved femoral heads clearly showed maintenance of an excellent surface finish of the current alumina. We conclude that the alumina ceramic femoral heads currently used are associated with a reduced rate of polyethylene wear.

Comparative study of in vitro methods used to analyse the activity of propolis extracts with different compositions against species of Candida.

AIMS: Propolis is known for its activity against micro-organisms and different in vitro assays have been used to evaluate this activity, frequently with contradictory results. METHODS AND RESULTS: Brazilian propolis from the state of São Paulo was extracted by maceration using different concentrations of ethanol and water. The resultant extracts were analysed by chromatographic methods. Several microbiological methods were compared to determine which one best evaluated the activity of the propolis extracts against species of Candida, with average minimal inhibitory concentration values between 6 and 12 mg ml(-1). CONCLUSIONS: Agar dilution in plates showed the clearest results. These were in agreement with the chromatographic analyses, which also identified the active substances. SIGNIFICANCE AND IMPACT OF THE STUDY: Although the active substances identified in this sample are typical of Brazilian propolis, their activity against Candida had not been recognized previously, demonstrating the importance of standardizing the correct combination of microbiological and chromatographic analyses.

Chemoprevention of azoxymethane-induced rat aberrant crypt foci by dietary zerumbone isolated from Zingiber zerumbet.

The modifying effects of dietary feeding of zerumbone isolated from Zingiber zerumbet on the development of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) were investigated in male F344 rats. Expression of cyclooxygenase (COX)-2 in colonic mucosa exposed to AOM and/or zerumbone was also assayed. In addition, we assessed the effects of zerumbone on cell proliferation activity of crypts by counting silver-stained nucleolar organizer regions protein (AgNORs) in colonic cryptal cell nuclei. To induce ACF rats were given three weekly subcutaneous injections of AOM (15 mg/kg body weight). They were also fed the experimental diet containing 0.01% or 0.05% zerumbone for 5 weeks, starting one week before the first dosing of AOM. AOM exposure produced 84+/-13 ACF/rat at the end of the study (week 5). Dietary administration of zerumbone caused reduction in the frequency of ACF: 72+/-17 (14% reduction) at a dose of 0.01% and 45+/-18 (46% reduction, p<0.001) at a dose of 0.05%. Feeding of zerumbone significantly reduced expression of COX-2 and prostaglandins in colonic mucosa. Zerumbone feeding significantly lowered the number of AgNORs in colonic crypt cell nuclei. These findings might suggest possible chemopreventive ability of zerumbone, through suppression of COX-2 expression, cell proliferating activity of colonic mucosa, and induction of phase II detoxification enzymes in the development of carcinogen-induced ACF.

Marked potentiation of activity of beta-lactams against methicillin-resistant Staphylococcus aureus by corilagin.

We found that an extract of Arctostaphylos uva-ursi markedly reduced the MICs of beta-lactam antibiotics, such as oxacillin and cefmetazole, against methicillin-resistant Staphylococcus aureus. We isolated the effective compound and identified it as corilagin. Corilagin reduced the MICs of various beta-lactams by 100- to 2,000-fold but not the MICs of other antimicrobial agents tested. The effect of corilagin and oxacillin was synergistic. Corilagin showed a bactericidal action when added to the growth medium in combination with oxacillin.

Two configurations of static magnetic fields for treating rheumatoid arthritis of the knee: a double-blind clinical trial.

OBJECTIVE: To assess the efficacy of a nonpharmacologic, noninvasive static magnetic device as adjunctive therapy for knee pain in patients with rheumatoid arthritis (RA). DESIGN: Randomized, double-blind, controlled, multisite clinical trial. SETTING: An American and a Japanese academic medical center as well as 4 community rheumatology and orthopedics practices. PATIENTS: Cohort of 64 patients over age 18 years with rheumatoid arthritis and persistent knee pain, rated greater than 40/100mm, despite appropriate use of medications. INTERVENTION: Four blinded MagnaBloc (with 4 steep field gradients) or control devices (with 1 steep field gradient) were taped to a knee of each subject for 1 week. MAIN OUTCOME MEASURES: The American College of Rheumatology recommended core set of disease activity measures for RA clinical trials and subjects' assessment of treatment outcome. RESULTS: Subjects randomly assigned to the MagnaBloc (n = 38) and control treatment groups (n = 26) reported baseline pain levels of 63/100mm and 61/100mm, respectively. A greater reduction in reported pain in the MagnaBloc group was sustained through the 1-week follow-up (40.4% vs 25.9%) and corroborated by twice daily pain diary results (p < .0001 for each vs baseline). However, comparison between the 2 groups demonstrated a statistically insignificant difference (p < .23). Subjects in the MagnaBloc group reported an average decrease in their global assessment of disease activity of 33% over 1 week, as compared with a 2% decline in the control group (p < .01). After 1 week, 68% of the MagnaBloc treatment group reported feeling better or much better, compared with 27% of the control group, and 29% and 65%, respectively, reported feeling the same as before treatment (p < .01). CONCLUSIONS: Both devices demonstrated statistically significant pain reduction in comparison to baseline, with concordance across multiple indices. However, a significant difference was not observed between the 2 treatment groups (p < .23). In future studies, the MagnaBloc treatment should be compared with a nonmagnetic placebo treatment to characterize further its therapeutic potential for treating RA. This study did elucidate methods for conducting clinical trials with magnetic devices.

Possibility of sialographic sonography: a Doppler phantom study.

OBJECTIVES: The purpose of this study was to develop a new diagnostic method that has the merits of both sialography and sonography. STUDY DESIGN: Saline solution and various contrast media (Urografin 76%; 100%, 90%, and 67% Lipiodol Ultra-Fluide; 5% and 1% barium sulfate; and Levovist) were injected into thin tubes at a rate of approximately 0.001 to 0.1 mL/s. The relationship between the Doppler signal intensity and the kind, concentration, and velocity of the fluid was analyzed. RESULTS: Levovist, 90% and 67% Lipiodol Ultra-Fluide, and the barium sulfate solutions produced Doppler signals. The mixture of Lipiodol Ultra-Fluide and saline solution produced high signals at any concentration, in contrast with the barium sulfate solutions. Signals could be observed at any speed, from the speed of normal sialography down to 0.001 mL/s, and there was a proportional relationship between signal intensity and velocity for all fluids producing signals. CONCLUSION: The fact that we could obtain high signals with several fluids indicates potential clinical diagnostic usefulness of sialographic sonography.

Acute effects of ovariectomy on wound healing of alveolar bone after maxillary molar extraction in aged rats.

Acute effects of ovariectomy on the bone wound healing processes after maxillary molar extraction in aged rats were examined by means of quantitative scanning electron microscopy (SEM), backscattered electron image (BSE) analysis and energy-dispersive X-ray (EDX) microanalysis. Six-month-old female rats underwent either sham operation or bilateral ovariectomy, and 7 days postoperatively, the maxillary first molars were extracted. On post-extraction days 7, 30 and 60, the dissected maxillary bone surfaces were examined by SEM to reveal the bone formative and resorptive areas around the extracted alveolar sockets. In addition, the resin-embedded maxillae were micromilled in the transverse direction through the extracted alveolar sockets, and the newly-formed bone mass on the buccal bone surfaces and within the extracted sockets was examined by BSE analysis. Compared with sham-operated controls, the extent of newly-formed bone mass on the buccal bone surfaces in OVX rats was significantly decreased, due to increased bone resorption. On the other hand, new bone formation within the extracted sockets was similar in the experimental groups. In EDX microanalysis of these newly-formed bone matrices, both Ca and P weight % and Ca/P molar ratio were similar in the experimental groups. Our results suggest that 1) acute estrogen deficiency induced by ovariectomy stimulates sustained bone resorption, but has less effect on bone formation, and 2) bone wound healing after maxillary molar extraction within extracted alveolar sockets is not significantly delayed by ovariectomy, but bony support by newly-formed bone mass on the maxillary bone surfaces at the buccal side of the extracted sockets is significantly decreased, due to increased bone resorption.

Effects of albumin infusion therapy on total and unbound bilirubin values in term infants with intensive phototherapy.

BACKGROUND: The purpose of the present study was to evaluate the effect of intravenous albumin administration on the serum total and unbound bilirubin values in term non-hemolytic hyperbilirubinemic neonates during intensive phototherapy. METHODS: Fifty-eight infants (gestational age 39.4 +/- 1.4 weeks; birth weight 3,245 +/- 435 g) were given phototherapy with similar light energy. Twenty infants (control group) received only phototherapy, while 38 others (albumin-treated group) were also given human albumin at 1 g/kg bodyweight, i.v., during the first 2 h of phototherapy. RESULTS: When comparing changes in total and unbound bilirubin values 0, 2, 6 and 24 h after entering the study between the albumin-treated group and the control group, there was a significant reduction in the serum unbound bilirubin values at the end of albumin treatment and at 6 and 24 h. However, there was no significant reduction in total serum bilirubin values during the study period. In the albumin-treated group, the mean serum unbound bilirubin reduction from the baseline level at the end of albumin treatment and at 6 and 24 h was 0.40 +/- 0.19, 0.41 +/- 0.20 and 0.43 +/- 0.20 microg/dL, respectively. CONCLUSIONS: The results suggest that albumin priming may be effective for an immediate reduction in serum unbound bilirubin values, the fraction that is potentially neurotoxic.

Antifungal activity of propolis on different species of Candida.

Propolis is a resinous material collected by bees from the buds or other parts of plants. It is known for its biological properties, having antibacterial, antifungal and healing properties. The antifungal activity of propolis was studied in sensitivity tests on 80 strains of Candida yeasts: 20 strains of Candida albicans, 20 strains of Candida tropicalis, 20 strains of Candida krusei and 15 strains of Candida guilliermondii. The yeasts showed a clear antifungal activity with the following order of sensitivity: C. albicans > C. tropicalis > C. krusei > C. guilliermondii. Patients with full dentures who used a hydroalcoholic propolis extract showed a decrease in the number of Candida.

Green tea polyphenols inhibit the sodium-dependent glucose transporter of intestinal epithelial cells by a competitive mechanism.

Intestinal glucose uptake is mainly performed by the sodium-dependent glucose transporter, SGLT1. The transport activity of SGLT1 was markedly inhibited by green tea polyphenols, this inhibitory activity being most pronounced in polyphenols having galloyl residues such as epicatechin gallate (ECg) and epigallocatechin gallate (EGCg). Experiments using brush-border membrane vesicles obtained from the rabbit small intestine demonstrated that ECg inhibited SGLT1 in a competitive manner, although ECg itself was not transported via SGLT1. The present results suggest that tea polyphenols such as ECg interact with SGLT1 as antagonist-like molecules, possibly playing a role in controlling the dietary glucose uptake in the intestinal tract.

In vitro culture of bovine preantral follicles.

Bovine preantral follicles (40-100 microm diameter at collection) were collected from ovaries of slaughtered cows and cultured in vitro with one of the four treatments: follicle stimulating hormone (FSH; 100 ng/ml) alone; FSH plus epidermal growth factor (EGF; 100 ng/ml); FSH plus insulin-transferrin-selenium (ITS; +1%) or FSH plus hypoxanthine (4 mM) in tissue culture medium (TCM 199) supplemented with 10% fetal calf serum (FCS), 0.1 mg/ml sodium pyruvate, 100 IU/ml of penicillin and 100 microg/ml streptomycin. The control culture medium was TCM 199 with supplements without any treatments. Follicles of each size were cultured separately in groups of one to three in 24-well multidishes each containing 500 microl of the appropriate culture medium. Culture commenced at follicle recovery (day 1) and continued for 10 days (harvested on day 11). In each case, half the medium was removed and replaced by fresh medium every third day. Follicle diameters were recorded on days 1, 5 and 11 of the experiment. At the end of the 10-day culture period, half of the follicles were stained with trypan blue to assess their potential viability and half were stained with bisbenzimide plus propidium iodine to estimate various morphological features of the follicles. Follicles of all initial sizes, on all culture treatments, increased in diameter during in vitro cultures with the greatest increases, both in absolute and proportional size, occurring between days 1 and 5 of culture. All of the culture medium supplements caused greater increases in follicle diameters than control medium at both days 5 and 11 of culture for all initial sizes of follicles (p<0.01). The most effective culture supplements for follicles of 40-, 60- and 80-microm initial diameter were FSH alone and FSH+EGF. The size of these follicles at both days 5 and 11 of culture on both the treatments was significantly larger (p<0.01) than follicles cultured in the presence of the other two supplementary treatments. The growth of follicles of 100-microm initial diameter did not differ between culture medium supplements. None of the culture media caused follicle size to increase to the initial diameters of the next larger size category during the 10 days of culture although follicles of 100-microm diameter achieved a diameter of 120 microm, after 4 days of culture. The overall follicular viability and morphology were better with treatments than the controls in all cases; however, there was no significant difference (p>0.05) among them. From this experiment, FSH and FSH plus EGF may be recommended for in vitro culture of smaller (40, 60 and 80 microm) follicles.

Identification of a taurine transport inhibitory substance in sesame seeds.

An ethanol extract from sesame seeds inhibited the taurine uptake in human intestinal epithelial Caco-2 cells. The uptake of such alpha-amino acids as leucine and glutamic acid was not inhibited by the extract, indicating that this inhibition is specific to the taurine uptake. The unknown inhibitor in the sesame extract was purifled by reversed-phase HPLC by monitoring the inhibitory effect on taurine uptake. The isolated substance was identified as lysophosphatidylcholine, linoleoyl (Lyso-PC), by NMR and MS analysis. Lyso-PC inhibited the taurine uptake in a dose-dependent manner with an IC50 value of approximately 200 microM. Although Lyso-PC is known to be a surface active and cell lytic compound, neither damage nor loss of integrity of the Caco2 cell monolayer was apparent after treating with 200 microM Lyso-PC. Inhibition was observed by incubating cells with Lyso-PC for only 1 min prior to the uptake experiments. These results suggest the direct effect of Lyso-PC on the cell membrane to be the main mechanism for this inhibition. Lyso-PC may play a role in the regulation of certain intestinal transporters.

Unresponsiveness of intrahepatic lymphocytes to bacterial superantigen: rapid development of suppressive Mac-1(high) cells in the mouse liver.

We previously found that a small dose (2 microg per mouse) of staphylococcal enterotoxin B (SEB) induced early emerging unresponsiveness in intrahepatic-lymphocyte populations (IHLs). The purpose of this study was to reveal the inducing role of accessory cells involved in IHLs in this phenomenon. IHLs prepared at 3 to 24 hours after SEB injection failed to proliferate in response not only to SEB but also to SEA, representing ligand-nonspecific unresponsiveness, whereas spleen cells (SPCs) and mesenteric lymph-node cells showed transient proliferation. Unresponsiveness in IHLs was related to a deficit of their accessory cell function as measured by coculture of irradiated IHLs and antigen-specific, type 1 T-helper (Th1) clone cells. High levels of nitrite were detected in the culture supernatant. Supplement of N(G)-monomethyl-L-arginine lowered nitrite levels and concurrently restored the proliferative response of Th1 cells, indicating the involvement of nitric oxide in suppression. Adherent cells prepared from IHLs well reproduced these results. As shown by flow cytometry, Mac-1(high) Ia(+) cells, which mainly included F4/80(+) cells (macrophages) and a minor population of CD11c(+) cells (dendritic cells), increased in proportion in IHLs but not in SPCs at 6 to 24 hours. Depletion of Mac-1(high) cells from IHLs with antibody-coated magnetic beads recovered the proliferative response. Depleted Mac-1(high) cells had a monocytoid appearance. In immunostained sections, Kupffer cells came to highly express both Mac-1 and Ia at 12 hours. These results indicate that Mac-1(high)Ia(+) adherent cells, largely Kupffer cells activated by SEB, nonspecifically suppress the proliferation of Th1 cells via nitric oxide production before manifestation of ligand-specific unresponsiveness.