A new assay for the genetic study of general anesthesia in Drosophila melanogaster: use in analysis of mutations in the X-chromosomal 12E region

We describe a new measure of the influence of general anesthetics on Drosophila that uses the robust tendency of fruit flies to briskly walk upwards after being tapped down. We expose flies to a fixed concentration of anesthetic gas in a 50 ml tube for a period of up to 1 h and then test the distribution of flies in the tube shortly after tapping them to its bottom. By measuring the effect of a series of anesthetic concentrations on the fraction of flies that fail to climb, we derive quantitative descriptors of the potency of the drug. This "distribution test" is superior to previous assays of anesthetic potency in terms of ease and reliability. We have used the assay to further the genetic analysis of several mutations that cluster on the X chromosome and are known to influence both neural function and anesthesia sensitivity. The results establish complementation patterns between the mutations, refine their genetic map positions, and open the way for the molecular identification of the relevant gene(s).

[Kinetics of plasma membrane and mitochondrial alterations in HL-60 cells undergoing apoptosis]

In the present study, VP16, an inhibitor of topoisomerase II, and NaN3, a chemical toxic substance, were used to induce apoptosis and necrosis of HL-60 cells, respectively. Cells were examined by transmission electron microscopy and by fluorescence microscopy after staining with Hoechst 33258 at 0, 2, 4, 8, 16 and 24 h of culture. Alterations of fluorescent intensity produced by FDA, Rh 123 and PI were measured by flow cytometry, which reflects sequential changes on plasma membrane permeability and the potential of mitochondrial membrane. The results indicated that the nuclear morphologic alteration of cells treated with VP-16 began at 4 hour of culture and the cells with condensed nucleus culminated at 8 h of culture and then reduced with no drop in cell counts, while the percentage of cells with fragmented nuclei reached its maximum at 24 h of culture accounting for some 80%. The potential of mitochondrial membrane of of apoptotic cells decreased gradually from 8 h of culture and showed obvious decline at 16 h of culture. In necrotic cells, the potential decreased by 50% at 4 h of culture which indicates an earlier and more rapid decline than that in apoptotic cells. Alteration of plasma membrane permeability appeared at 8 h of culture and showed a steady increase over time. It was concluded that plasma membrane permeability and mitochondrial membrane potential could reflect the development and degree of apoptosis, and the combination of these two criteria with nuclear morphology revealed by staining with Hoechst 33258 would be a simple and reliable assay for apoptosis and its progression.

[Ethanol-induced apoptosis in human HL-60 cells]

The purpose of this study was to examine the effect of ethanol on apoptosis of human promyelocytic leukemia cell line HL-60 cells and search for a possible reason for reduced PMNs, monocytes, lymphocytes in the blood of alcoholics. Human promyelocytic leukemia cell line HL-60 cells was used as a model of apoptosis, with ethanol being the interfering factor. Qualitative and quantitative detection was done by both electron microscopy and flow cytometry. Compared with the control treatment of HL-60 cells with ethanol at 50, 100, 150, 200, 250 mmol/L for 3 days increased apoptotic cells significantly (P < 0.01), and apoptosis was dose-dependent for ethanol. It suggest that ethanol can induce apoptosis of HL-60 cells. So as far as reduced PMNs, monocytes, phagocytes and lymphocytes of alcoholics are concerned, ethanol-induced apoptosis may well be an important reason.

[The clinical application of the reverse island skin flap supplied by the superficial sural artery]

OBJECTIVE

To conform the reliability of the reverse island skin flap supplied by the superficial sural artery in clinical applications.

METHODS

The distally based superficial sural artery flap was designed on the posterior aspect of the leg. 15 patients were treated with this flap, who had soft-tissue shortage of the lower third of the leg, the foot or the heel. The size of the flap ranged from 10 cm x 8 cm to 5 cm x 4 cm.

RESULTS

All flaps survived. The results were satisfactory after 6 to 18 months' postoperative follow-up.

CONCLUSIONS

The blood supply of this flap is reliable without sacrificing the major arteries. Flap elevation is easy and quick. This flap may provide a new method in reconstructioning the soft-tissue shortage of the lower leg, the foot and the heel.

Both p38alpha(MAPK) and JNK/SAPK pathways are important for induction of nitric-oxide synthase by interleukin-1beta in rat glomerular mesangial cells

Interleukin 1beta (IL-1beta) induces expression of the inducible nitric-oxide synthase (iNOS) with concomitant release of nitric oxide (NO) from glomerular mesangial cells. These events are preceded by activation of the c-Jun NH(2)-terminal kinase/stress-activated protein kinase (JNK/SAPK) and p38(MAPK). Our current study demonstrates that overexpression of the dominant negative form of JNK1 or p54 SAPKbeta/JNK2 significantly reduces the iNOS protein expression and NO production induced by IL-1beta. Similarly, overexpression of the kinase-dead mutant form of p38alpha(MAPK) also inhibits IL-1beta-induced iNOS expression and NO production. In previous studies we demonstrated that IL-1beta can activate MKK4/SEK1, MKK3, and MKK6 in renal mesangial cells; therefore, we examined the role of these MAPK kinases in the modulation of iNOS induced by IL-1beta. Overexpression of the dominant negative form of MKK4/SEK1 decreases IL-1beta-induced iNOS expression and NO production with inhibition of both SAPK/JNK and p38(MAPK) phosphorylation. Overexpression of the kinase-dead mutant form of MKK3 or MKK6 demonstrated that either of these two mutant kinase inhibited IL-1beta-induced p38(MAPK) (but not JNK/SAPK) phosphorylation and iNOS expression. Interestingly overexpression of wild type MKK3/6 was associated with phosphorylation of p38(MAPK); however, in the absence of IL-1beta, iNOS expression was not enhanced. This study suggests that the activation of both SAPK/JNK and p38alpha(MAPK) signaling cascades are necessary for the IL-1beta-induced expression of iNOS and production of NO in renal mesangial cells.

Mechanisms through which PDGF alters intracellular calcium levels in U-1242 MG human glioma cells

PDGF-BB induces a rapid, sustained increase in intracellular calcium levels in U-1242 MG cells. We used several calcium channel blockers to identify the types of channels involved. L channel blockers (verapamil, nimodipine, nicardipine, nitrendipine and taicatoxin) had no effect on PDGF-BB induced alterations in intracellular calcium. Blockers of P, Q and N channels (omega-agatoxin-IVA, omega-conotoxin MVIIC and omega-conotoxin GVIA) also had no effect. This indicates that these channels play an insignificant role in supplying the Ca2+ necessary for PDGF stimulated events in U-1242 MG cells. However, a T channel blocker (NDGA) and the non-specific (NS) calcium channel blockers (FFA and SK&F 9365) abolished PDGF-induced increases in intracellular calcium. This indicates that PDGF causes calcium influx through both non-specific cationic channels and T channels. To study the participation of intracellular calcium stores in this process, we used thapsigargin, caffeine and ryanodine, all of which cause depletion of intracellular calcium stores. The PDGF effect was abolished using both thapsigargin and caffeine but not ryanodine. Collectively, these data indicate that in these human glioma cells PDGF-BB induces release of intracellular calcium from caffeine- and thapsigargin-sensitive calcium stores which in turn lead to further calcium influx through both NS and T channels.

The effects of classic antipsychotic haloperidol plus the extract of ginkgo biloba on superoxide dismutase in patients with chronic refractory schizophrenia

OBJECTIVES

To explore the association between schizophrenic symptoms and superoxide dismutase (SOD), and to investigate the effect of classic antipsychotic haloperidol plus the extract of Ginkgo biloba (EGb) on SOD.

METHODS

In 54 patients with chronic refractory schizophrenia, 27 were treated with haloperidol plus EGb (group 1), and the rest received haloperidol plus placebo (group 2). Superoxide dismutase (SOD) levels of these patients were measured before and after treatment and compared with the levels of 25 healthy volunteers. Therapeutic efficacy was equated with a change in clinical rating scores assessed by standardized measurement tools including the Scale for Assessment of Positive Symptoms (SAPS) and the Scale for Assessment of Negative Symptoms (SANS).

RESULTS

Patients in group 1 improved significantly as demonstrated by scores from both SAPS and SANS, while those in group 2 only by scores from SANS. Assessed by SAPS, the response of patients receiving haloperidol plus EGb was more significant than those receiving haloperidol only. SOD levels before treatment in all patients were significantly higher than those in normal controls. After treatment, SOD levels decreased significantly in group 1 but not in group 2. In addition, before treatment, SOD levels in all patients correlated significantly with SAPS score. The levels of SOD measured before treatment were also correlated with the improvement of patients as measured by SAPS and SANS after 12 weeks.

CONCLUSIONS

EGb may enhance the efficacy of classic antipsychotic haloperidol on schizophrenia, especially on positive symptoms. It may work through an antioxidant efficacy that is involved in the therapeutic mechanism.

Evaluation of the inhibition of other metalloproteinases by matrix metalloproteinase inhibitors

Two series of compounds synthesized as specific matrix metalloproteinase (MMP) inhibitors have been evaluated for their inhibition of non-MMPs. In a series of substituted succinyl hydroxamic acids, some were found to be significant (IC50 < 1 microM) inhibitors of leucine (microsomal) aminopeptidase, neprilysin (3.4.24.11), and thermolysin. Macrocyclic compounds in which the alpha carbon of the succinyl hydroxamate is linked to the side chain of the P2' amino acid were found to be good inhibitors of aminopeptidase, but not of neprilysin or thermolysin. Compounds of neither series were found to be significant inhibitors of angiotensin converting enzyme or carboxypeptidase A.

Depletion of hematogenous macrophages promotes partial hindlimb recovery and neuroanatomical repair after experimental spinal cord injury

Traumatic injury to the spinal cord initiates a series of destructive cellular processes which accentuate tissue damage at and beyond the original site of trauma. The cellular inflammatory response has been implicated as one mechanism of secondary degeneration. Of the various leukocytes present in the spinal cord after injury, macrophages predominate. Through the release of chemicals and enzymes involved in host defense, macrophages can damage neurons and glia. However, macrophages are also essential for the reconstruction of injured tissues. This apparent dichotomy in macrophage function is further complicated by the overlapping influences of resident microglial-derived macrophages and those phagocytes that are derived from peripheral sources. To clarify the role macrophages play in posttraumatic secondary degeneration, we selectively depleted peripheral macrophages in spinal-injured rats during a time when inflammation has been shown to be maximal. Standardized behavioral and neuropathological analyses (open-field locomotor function, morphometric analysis of the injured spinal cord) were used to evaluate the efficacy of this treatment. Beginning 24 h after injury and then again at days 3 and 6 postinjury, spinal cord-injured rats received intravenous injections of liposome-encapsulated clodronate to deplete peripheral macrophages. Within the spinal cords of rats treated in this fashion, macrophage infiltration was significantly reduced at the site of impact. These animals showed marked improvement in hindlimb usage during overground locomotion. Behavioral recovery was paralleled by a significant preservation of myelinated axons, decreased cavitation in the rostrocaudal axis of the spinal cord, and enhanced sprouting and/or regeneration of axons at the site of injury. These data implicate hematogenous (blood-derived) macrophages as effectors of acute secondary injury. Furthermore, given the selective nature of the depletion regimen and its proven efficacy when administered after injury, cell-specific immunomodulation may prove useful as an adjunct therapy after spinal cord injury.

Decrease and structural modifications of phosphatidylethanolamine plasmalogen in the brain with Alzheimer disease

Several lipid modifications, some of which were attributed to oxidative stress, have been reported in the brains of patients with Alzheimer disease (AD). To evaluate this possibility, all phospholipids and their ether subclasses from the frontal cortex, hippocampus, and the white matter of AD brain were analyzed by high performance liquid chromatography and gas chromatography. The total phospholipid in the frontal cortex and hippocampus decreased on a DNA basis by about 20% and this change was essentially explained by a selective decrease in phosphatidylethanolamine and phosphatidylcholine. The lower content of phosphatidylethanolamine was due to a specific decrease in the plasmalogen subclass. Phosphatidylethanolamine plasmalogen was also the only lipid exhibiting major structural modifications: a significant decrease in polyunsaturated fatty acids and oleic acid as well as a shift of the aldehyde pattern from 18:1 to 18:0. The only modification observed in the other phospholipids was a decrease in oleic acid in diacyl-phosphatidylethanolamine and diacyl-phosphatidylcholine. None of these changes were observed in the white matter. Both the vinyl ether bond of phosphatidylethanolamine plasmalogen and polyunsaturated fatty acids are major targets in oxidative stress; thus, these specific lipid modifications strongly support the involvement of free radicals in the pathogenesis of AD.

[Relationship between unhealthy dietary behavior and blood lipids and lipid peroxides in coronary heart disease patients]

The effects of unhealthy dietary behavior on blood lipids(TC, TG, HDL-C, LDL-C) and lipid peroxides (LPO) and the occurrence of coronary heart disease(CHD) were measured in 97 CHD patients and 97 controls without any clinical appearance of cardiovascular or cerebrovascular diseases. The results showed that the serum level of TC, TG, HDL-C, LDL-C and LPO were significantly higher in CHD group than control group. More unhealthy dietary behavior was observed in CHD group than in control group. The odds ratio of the population with more than 3 items of unhealthy dietary behavior was 3.88. The results of this study suggested that unhealthy dietary behavior might play an important role in increasing the risk of CHD.

[Study on relative factors in endoscopic sinus surgical procedure]

OBJECTIVE

In order to investigate the factors which affect the operative treatment effect of FESS.

METHOD

215 cases suffered functional endoscopic sinus surgery (FESS) from May 1994 to December 1997 were analysed.

RESULT

The clinical curative rate was 75.8% and the improving rate was 96.3%.

CONCLUSION

The effect shows that surgical procedure is closely related to following factors: mechanic of operation, drugs taken in pre-operation, kinds of anesthsia, clinical stage of chronic sinusitis, nasal poplys and skill of surgeons.

[Experimental study and preliminary clinical application of bacterial collagenase in catabolizing scars]

OBJECTIVE

To investigate the mechanism of collagenase in degradation of hypertrophic scars and observe the clinical effects of this therapy.

METHODS

Both animal experiment and clinical trial were conducted.

RESULTS

The injection of collagenase into the hypertrophic scar tissues in nude mice resulted in 86% volume reduction after two injections within two weeks, while the control tissues reduced only by 35% during the same time. Clinically, 13 cases were treated with intralesional injection of bacterial collagenase. The volume reduction rate was 46.92% in average within two weeks. The volume reduction in 4 of 13 cases was above 50%. Three to sixteen months' follow-up of five patients revealed that only one case of keloid recurred after treatment in the second month. Examinations of histological sections and TEM showed the dissolved collagen fiber clearly.

CONCLUSION

Collagenase can degrade collagen fiber directly. The prompt significant effects and the mild complications make it a prospective therapy.

[Study on the steroid constituents of soft coral Lobophytum microspiculatum]

The soft coral Lobophytum microspiculatum collected from Xisa Islands of the South China Sea was immersed in and extracted with ethyl alcohol and the extract was concentrated, and then partitioned between ethyl acetate and water. The portion soluble in ethyl acetate was subjected to column chromatography over Sillca H, eluted with a step gradient of EtOAc and petroleum ether. The sterols were obtained from 20% EtOAc-petroleum ether eluent portion. By means of GC/MS method, the sterols were identified to be: cholesta-26-methyl-ol; ergosta-8, 22-dien-3 beta-ol, 24-methyl; ergosta-5, 22-dien-3 beta-ol, 23, 24-dimethyl; cholesta-5,22(23)-dien-3 beta-ol, 22,24-dimethyl; cholesterol; ergosta-5,22-dien-3 beta-ol, 24-methyl; ergosta-5,22-dien-3 beta-ol, 22,24-dimethyl, 24-methyl-cholesterol; ergosta-7-en-3 beta-ol, 24-methyl; nor-ergosta-7-en-3 beta-ol and gorgosterol. Among them cholest-5,22(23)-3 beta-ol, 22,24-dimethyl (4) is a new compound which was found at the first time from the nature. This finding gave a further prove for the biogenesis path way of gorgosterol.

Chain walking: A new strategy to control polymer topology

Ethylene pressure has been used to control the competition between isomerization (chain walking) and monomer insertion processes for ethylene coordination polymerization catalyzed by a palladium-alpha-diimine catalyst. The topology of the polyethylene varies from linear with moderate branching to "hyperbranched" structures. Although the overall branching number and the distribution of short-chain branching change very slightly, the architecture or topology of the polyethylene changes from linear polyethylene with moderate branches at high ethylene pressures to a hyperbranched polyethylene at low pressures.

Gender differences in late positive components evoked by human faces

Event-related potentials (ERPs) were recorded in male and female participants in response to 32 male and 32 female faces. Participants were instructed to simply look carefully at each face; after ERP collection they were asked to rate each face on a 5-point attractiveness scale. A positive correlation between average rating and average P300 scores to opposite sex faces was observed in male (r = .40) and in preovulatory (r = .41) and postovulatory (r = .44) female subjects. Correlations to same sex faces were only found in postovulatory females (r = .61). Male participants showed a much larger average P300 than did female participants, and the P300 evoked in female participants was unexpectedly larger to female than to male faces. Neither task relevance nor stimulus probability is a plausible explanations for these findings because they were experimentally controlled. These results support the emotional value hypothesis, according to which classical P300 processes reflect an affective evaluation of the stimulus, which in turn produces context updating.

[Reinfusion of autologous shed blood after joint replacement]

OBJECTIVE

To evaluate the results of reinfusion of autologous shed blood after joint replacement.

METHODS

From February 1996 to March 1998, we selected 36 patients for 56 joint replacements. Apart from preoperative donation of autologous blood, all patients received transfusion of unwashed autologous drained blood from hips and knees after arthroplasty. The CBCIIConstaVac blood conservation system was used to salvage shed blood. Among the patients, 8 hips and 48 knees were involved. 12 patients had rheumatoid arthritis, 16 osteoarthritis, 5 ankylosing spondylitis, and 3 other arthritis.

RESULTS

36 patients received 24 260 ml (50%) autologous shed blood, 9 700 ml (20%) reserved autologous blood, and 14 600 ml (30%) allogenic blood. 15 patients experienced transient febrile reaction at the time of reinfusion, no other clinic abnormalities were discovered after reinfusion.

CONCLUSIONS

Reinfusion of autologous shed blood is a safe and effective to decrease the use of allogenic blood and avoid the complications of its transfusion.

The protective role of plasmalogens in iron-induced lipid peroxidation

The role of plasmalogens in iron-induced lipid peroxidation was investigated in two liposomal systems. The first consisted of total brain phospholipids with and without plasmalogens, and the second of phosphatidylethanolamine/phosphatidylcholine liposomes with either diacyl- or alkenylacyl-phosphatidylethanolamine. By measuring thiobarbituric acid reactive substances, oxygen consumption, fatty acids and aldehydes, we show that plasmalogens effectively protect polyunsaturated fatty acids from oxidative damage, and that the vinyl ether function of plasmalogens is consumed simultaneously. Furthermore, the lack of lag phase, the increased antioxidant efficiency with time, and the experiments with lipid- and water-soluble azo compounds, indicate that plasmalogens probably interfere with the propagation rather than the initiation of lipid peroxidation, and that the antioxidative effect cannot be related to iron chelation.

Assessment of the mechanism by which prolactin stimulates progesterone production by early corpora lutea of pigs

Previously, we reported that administration of prolactin (PRL) during the early luteal phase in sows increases plasma progesterone concentrations. In the current study, we searched for the mechanisms by which PRL exerts this luteotrophic effect. The objectives of the study were (1) to examine the effect of PRL and/or low-density lipoproteins (LDL) on progesterone production by porcine luteal cells derived from early corpora lutea, and (2) to assess the ability of PRL to activate phosphoinositide-specific phospholipase C (PI-PLC) and protein kinase C (PKC) in these luteal cells. Ovaries with early corpora lutea (day 1-2 of the oestrous cycle) were obtained from the slaughterhouse. Progesterone production by dispersed luteal cells was measured after treatment with PRL, phorbol 12-myristate 13-acetate or inhibitors of PKC in the presence or absence of LDL. LDL increased progesterone concentration in the incubation medium (304.5 vs 178.6 ng/ml in control, P<0.05). PRL augmented LDL-stimulated progesterone secretion by luteal cells (to 416 ng/ml, P<0.05), but PRL alone did not affect progesterone production (209.6 ng/ml, P>0.05). Staurosporine, a PKC inhibitor, inhibited progesterone secretion stimulated by the combined action of LDL and PRL; however, such inhibition was not demonstrated when cells were treated with the PKC inhibitor, H-7. PKC activation was assessed by measuring the specific association of [H]phorbol dibutyrate (H-PDBu) with luteal cells after treatment with PRL or ionomycin (a positive control). PRL and ionomycin increased H-PDBu-specific binding in early luteal cells by 28+/-5.5% (within 5 min) and 70.2+/-19.3% (within 2 min) over control binding respectively (P<0.05). In addition, PRL did not augment the LDL-stimulated progesterone production in PKC-deficient cells. In contrast with PKC, total inositol phosphate accumulation, as well as intracellular free calcium concentrations, were not affected by PRL in the current study. We conclude that PRL, in the presence of LDL, stimulates progesterone production by early corpora lutea in vitro. Moreover, PRL appears to activate PKC, but not PI-PLC, in these cells. Thus intracellular transduction of the PRL signal may involve activation of PKC that is not dependent on PI-PLC.

Brain-derived neurotrophic factor stimulates hindlimb stepping and sprouting of cholinergic fibers after spinal cord injury

Neurotrophic factors have been proposed as a therapeutic treatment for traumatic brain and spinal cord injury. The present study determined whether exogenous administration of one such factor, brain-derived neurotrophic factor (BDNF), could effect behavioral recovery and/or histopathological changes after spinal cord injury. Adult rats received a mild or moderate contusion injury or complete transection of the mid-thoracic spinal cord. Immediately thereafter, they were infused intrathecally with vehicle or BDNF for 28 days. Behavioral recovery was evaluated for 6 weeks after injury, at which time the rats were sacrificed and the spinal cord tissue was examined histologically. The infusion of BDNF resulted in acute stimulation of hindlimb activity. These effects included activation of alternating airstepping in injured rats when the hindlimbs were unloaded as well as slight improvements in the rate of recovery in open field locomotion score. BDNF infusion was also associated with enhanced growth of cholinergic fibers at the injury epicenter, but did not affect white matter sparing or density of serotonergic axons at or below the injury site. Based on immunohistochemical detection of BDNF protein distribution, these described effects are likely to be mediated by the activation of cells and axons within the central injury region and the along the peripheral rim of the spinal cord. Together, these findings demonstrate that the exogenous infusion of BDNF after spinal trauma can influence postinjury outcome through mechanisms that include acute stimulation of hindlimb activity and neuritogenesis at the injury site.

[Comparative study on biological characteristics and ultrastructure of the fibroblasts derived from normal skin, hypertrophic scar and keloidin in vitro culture]

OBJECTIVE

This study was to investigate the in vitro cultivation, biological characteristics and ultrastructure of the fibroblasts derived from normal skin, hypertrophic scar and keloid, to elucidate the value of their application.

METHOD

A comparative study was performed on cell proliferation, cell morphology, cytogenetic feature and cell ultrastructure of fibroblasts from normal skin, hypertrophic scar and keloid by means of the technique of in vitro culture.

RESULT

The results indicated that the fibroblasts isolated from normal skin, hypertrophic scar and keloid exhibited similar morphology and growth rates. The cytogenetic feature and cell ultrastructure were also alike.

CONCLUSION

According to our study and that of others, we conclude that it is entirely feasible to establish an in vitro culture model of fibroblasts from normal skin for investigation, prevention and treatment of scars.

Interleukin-1beta-induced cyclooxygenase-2 expression requires activation of both c-Jun NH2-terminal kinase and p38 MAPK signal pathways in rat renal mesangial cells

The inflammatory cytokine interleukin-1beta (IL-1beta) induces cyclooxygenase-2 (Cox-2) expression with a concomitant release of prostaglandins from glomerular mesangial cells. We reported previously that IL-1beta rapidly activates the c-Jun NH2-terminal/stress-activated protein kinases (JNK/SAPK) and p38 mitogen-activated protein kinase (MAPK) and also induces Cox-2 expression and prostaglandin E2 (PGE2) production. The current study demonstrates that overexpression of the dominant negative form of JNK1 or p54 JNK2/SAPKbeta reduces Cox-2 expression and PGE2 production stimulated by IL-1beta. Similarly, overexpression of the kinase-dead form of p38 MAPK also inhibits IL-1beta-induced Cox-2 expression and PGE2 production. These results suggest that activation of both JNK/SAPK and p38 MAPK is required for Cox-2 expression after IL-1beta activation. Furthermore, our experiments confirm that IL-1beta activates MAP kinase kinase-4 (MKK4)/SEK1, MKK3, and MKK6 in renal mesangial cells. Overexpression of the dominant negative form of MKK4/SEK1 decreases IL-1beta- induced Cox-2 expression with inhibition of both JNK/SAPK and p38 MAPK phosphorylation. Overexpression of the kinase-dead form of MKK3 or MKK6 demonstrated that either of these two mutant kinases inhibited IL-1beta-induced p38 MAPK phosphorylation and Cox-2 expression but not JNK/SAPK phosphorylation and activation. This study suggests that the activation of both JNK/SAPK and p38 MAPK signaling cascades is required for IL-1beta-induced Cox-2 expression and PGE2 synthesis.