Outcomes of flexor tendon repairs in zone 2 subzones with early active mobilization

We report on the outcomes of flexor tendon repair in zone 2 subzones with early active mobilization in 102 fingers in 88 consecutive patients. There were 28, 53, 15, and six fingers with repairs in zones 2A to 2D, respectively. Rupture of the repair occurred in four fingers, all in zone 2B. Excluding those with repair ruptures, the mean total active motion was 230° (range 143°-286°). Evaluated with Tang's criteria, the outcomes were ranked excellent in 39 fingers, good in 46, fair in ten, poor in three, and failure in four. The outcomes in zone 2C were significantly inferior to those in zones 2B and 2D ( p = 0.02). Our results suggest that the tendon laceration in the area covered by the A2 pulley (zone 2C) is the most difficult area to obtain satisfactory active digital motion and tendon repair in zone 2B is the area where the risk of rupture is highest.

LEVEL OF EVIDENCE

IV.

Three-dimensional charge density wave order in YBa2Cu3O6.67 at high magnetic fields

Charge density wave (CDW) correlations have been shown to universally exist in cuprate superconductors. However, their nature at high fields inferred from nuclear magnetic resonance is distinct from that measured with x-ray scattering at zero and low fields. We combined a pulsed magnet with an x-ray free-electron laser to characterize the CDW in YBa2Cu3O6.67 via x-ray scattering in fields of up to 28 tesla. While the zero-field CDW order, which develops at temperatures below ~150 kelvin, is essentially two dimensional, at lower temperature and beyond 15 tesla, another three-dimensionally ordered CDW emerges. The field-induced CDW appears around the zero-field superconducting transition temperature; in contrast, the incommensurate in-plane ordering vector is field-independent. This implies that the two forms of CDW and high-temperature superconductivity are intimately linked.

Ibudilast, a mixed PDE3/4 inhibitor, causes a selective and nitric oxide/cGMP-independent relaxation of the intracranial vertebrobasilar artery

Ibudilast, a mixed phosphodiesterase (PDE) 3/4 inhibitor, is a cerebral vasodilator widely used in Japan for treating post-stroke dizziness. However, little studies have been conducted on the vasorelaxant effects of PDE inhibitors in the vertebrobasilar artery associated with dizziness onset. The in vitro vasorelaxant properties of ibudilast were, therefore, investigated by comparing with known selective PDE inhibitors, using vertebrobasilar arteries. Vasorelaxant activities of PDE3, PDE4, PDE5 inhibitors, and ibudilast were assessed in 5-hydroxytryptamine precontracted ring preparations from rabbit intracranial and extracranial vertebrobasilar arteries. Ibudilast more selectively relaxed the intracranial than extracranial artery. Similarly, selective PDE3 and PDE4 inhibitors showed higher selectivity for intracranial arteries. Furthermore, like selective PDE4 inhibitor, the vasorelaxation by ibudilast accompanied by increase in cAMP levels was inhibited by the adenylyl cyclase inhibitor SQ22536 in intracranial arteries. Next, it was examined whether nitric oxide (NO)/cGMP signaling is involved in this vasorelaxation in intracranial arteries. The suppression of NO/cGMP signaling by an NO synthase inhibitor or a guanylyl cyclase inhibitor potentiated the vasorelaxion by a PDE3 inhibitor and reduced that by a PDE4 inhibitor, while either suppression of the signaling had little influence on that by ibudilast. These results suggest that ibudilast has the high vasoselectivity for intracranial artery based on a mixed PDE3 and PDE4-inhibition, and effectively relaxes intracranial arteries independently of NO/cGMP signaling because of its vasorelaxation compensated by either PDE3- or PDE4-inhibition depending on the state of NO/cGMP signaling change.

[Combined thoracoscopic and open chest approach of lobectomy with inferior chest wall resection for advanced lung cancer]

Patients with advanced non-small cell lung cancer invading a chest wall are surgical candidates if complete resection is possible. When a primary tumor locating the lower lobe invades an inferior chest wall, either a wide skin incision or double skin incisions to secure surgical views both for dissection of hilum and mediastinum and for inferior chest wall resection is necessary. Wider incision causes higher rate of wound necrosis and infection. We describe a combined approach of thoracoscopic and open chest surgery for lobectomy and inferior chest wall resection, respectively. Patient was a 68-year-old man with an advanced non-small cell lung cancer. Video-assisted thoracoscopic middle and lower lobectomies and mediastinal nodal dissection was completed via 5 ports. Chest wall resection including the posterior portion of the 9th and 10th ribs and the transverse process followed inferior postero-lateral thoracotomy. Postoperative course was uneventful. The present surgical approach can avoid a wide thoracotomy for an advanced lung cancer invading an inferior chest wall.

Pharmacological effects of imidafenacin (KRP-197/ONO-8025), a new bladder selective anti-cholinergic agent, in rats. Comparison of effects on urinary bladder capacity and contraction, salivary secretion and performance in the Morris water maze task

Imidafenacin (CAS 170105-16-5, KRP-197, ONO-8025) has been developed for the treatment of overactive bladder as a new anti-cholinergic with high affinities for muscarinic acetylcholine M3 and M1 receptors. The pharmacological profiles of imidafenacin on the urinary bladder function by determining carbamylcholine (CCh)-induced decrease in bladder capacity and distention-induced rhythmic bladder contraction in conscious rats were investigated. In addition, effects of imidafenacin on CCh-induced salivary secretion and performance in the Morris water maze task in rats were investigated to evaluate side effects, such as dry mouth and cognitive dysfunction in the central nervous system (CNS). Imidafenacin prevented the CCh-induced decrease in bladder capacity dose-dependently with an ID50 of 0.055 mg/kg. On the distention-induced rhythmic bladder contraction, imidafenacin, propiverine, tolterodine, oxybutynin and darifenacin showed inhibitory effects with ID30's of 0.17, 15, 3.0, 3.2 and 0.85 mg/kg, respectively. The rank order of inhibitory potency was: imidafenacin > darifenacin > tolterodine > or = oxybutynin > propiverine. Imidafenacin, propiverine, tolterodine, oxybutynin and darifenacin showed inhibitory effects on the CCh-stimulated salivary secretion with ID50's of 1.5, 14, 15, 4.4 and 1.2 mg/kg, respectively. The rank order of inhibitory potency was: darifenacin > or = imidafenacin > oxybutynin > propiverine > or = tolterodine. Imidafenacin at the doses of 1 and 10 mg/ kg did not affect the escape latencies in the Morris water maze task compared with those in vehicle controls. Oxybutynin at the dose of 100 mg/kg induced a significant increase in the escape latencies, but propiverine at the dose of 100 mg/kg did not induce significant changes. These results suggest that imidafenacin inhibits urinary bladder contraction to a greater extent than the salivary secretion (compared with the M3 receptor selective antagonist, darifenacin, and the non-selective antagonists, propiverine, tolterodine and oxybutynin) or the CNS functions, such as performance in the Morris water maze task (compared with oxybutynin). In conclusion, imidafenacin has organ selectivity for the bladder over the salivary gland, without influence on the central nervous system such as spatial learning and memory.

Effects of imidafenacin (KRP-197/ONO-8025), a new anti-cholinergic agent, on muscarinic acetylcholine receptors. High affinities for M3 and M1 receptor subtypes and selectivity for urinary bladder over salivary gland

Imidafenacin (CAS 170105-16-5, KRP-197, ONO-8025) is an antagonist for the muscarinic acetylcholine (ACh) receptor currently under development for the treatment of overactive bladder. Affinities of imidafenacin and other drugs for muscarinic ACh receptor subtypes were investigated by examining inhibitory effects on ACh release in the rat urinary bladder and K+ efflux in the rat salivary gland in functional and binding assays. In the functional assay, imidafenacin had higher affnities for M3 and M1 receptors than for the M2 receptor. In contrast, metabolites of imidafenacin (M-2, M-4 and M-9) had low affinities for muscarinic ACh receptor subtypes. Darifenacin had selectivity for the M3 receptor, while propiverine, tolterodine and oxybutynin had no selectivity for muscarinic ACh receptors. In carbamylcholine (CCh)-induced contraction in the urinary bladder, imidafenacin, propiverine, tolterodine and oxybutynin had affinities similar to those for the M3 receptor in the ileum. In the binding assay for human muscarinic ACh receptor subtypes, imidafenacin had higher affinities for m3 and m1 receptors than for m2 receptor, but tolterodine had no selectivity for m1, m2 and m3 receptors. In ACh release in the urinary bladder, inhibitory effects of imidafenacin, tolterodine, oxybutynin and darifenacin seemed to be partially mediated by the M1 receptor. In ACh-induced and electrical stimulation-induced K+ efflux from the salivary gland, inhibitory effects (IC50) of imidafenacin, propiverine, tolterodine, oxybutynin and darifenacin might be closely related to those for the M3 receptor in the ileum. These results suggest that imidafenacin more strongly antagonizes cholinomimetics on M3 and M1 receptors than on the M2 receptor. Moreover, imidafenacin seems to inhibit the contraction of the bladder smooth muscle by mediating antagonism to the M3 receptor and to regulate ACh release by mediating prejunctional facilitatory M1 receptor. Imidafenacin also inhibited K+ efflux from the salivary gland mainly by mediating the M3 receptor. Therefore, imidafenacin will have higher affinities for M3 and M1 receptors and higher selectivity for the urinary bladder than for the salivary gland.

The transcriptional landscape of the mammalian genome

This study describes comprehensive polling of transcription start and termination sites and analysis of previously unidentified full-length complementary DNAs derived from the mouse genome. We identify the 5' and 3' boundaries of 181,047 transcripts with extensive variation in transcripts arising from alternative promoter usage, splicing, and polyadenylation. There are 16,247 new mouse protein-coding transcripts, including 5154 encoding previously unidentified proteins. Genomic mapping of the transcriptome reveals transcriptional forests, with overlapping transcription on both strands, separated by deserts in which few transcripts are observed. The data provide a comprehensive platform for the comparative analysis of mammalian transcriptional regulation in differentiation and development.

Effects of carbocisteine on altered activities of glycosidase and glycosyltransferase and expression of Muc5ac in SO2-exposed rats

Carbocisteine is a mucoregulatory drug regulating fucose and sialic acid contents in mucus glycoprotein. To investigate the mechanism of carbocisteine action, we evaluated the effects of carbocisteine on the activity of fucosidase, sialidase, fucosyltransferase and sialyltransferase, and on the expression of Muc5ac mRNA in the airway epithelium of SO(2)-exposed rats. Wistar rats were repeatedly exposed to a 300-ppm SO(2) gas for 44 days. Carbocisteine (125 and 250 mg/kg x2/day) was administered for 25 days after 20 days of SO(2) gas exposure. These enzyme activities were measured by fluorogenic substrate or glycoproteinic exogenous acceptor method. The expression levels of Muc5ac mRNA and protein were determined with real-time reverse transcriptase-polymerase chain reaction (real-time RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Carbocisteine (250 mg/kg x2/day) inhibited all the changes in these enzyme activities and the expressions of Muc5ac mRNA and protein in the lung after repeated SO(2) exposure. These findings suggest that carbocisteine may normalize fucose and sialic acid contents in mucin glycoprotein through regulation of these enzyme activities, and inhibition of both Muc5ac mRNA and protein expressions in SO(2)-exposed rats.

Small cell carcinoma of the endometrium: report of three cases and literature review

BACKGROUND

Small cell carcinoma of the endometrium is extremely rare. Aim. We reported three cases of this rare tumor and reviewed the literature.

CASES

Case 1 was a 54-year-old woman and case 3 was a 58-year-old woman. Both patients presented with vaginal bleeding. Case 2, a 53-year-old woman, had no symptoms and had a vaginal-cervical smear suspicious for malignancy. All patients underwent surgery and their tumors originated in the endometrium. In all three cases, pathological examination revealed small cell carcinoma of endometrium, and immunohistochemical reactivity for one or more neuroendocrine markers was found in all cases. Under electron microscopy in case 2 and case 3, dense core granules in the cytoplasm of tumor cells were found only in case 3. Case 3 was stage IIIA and died of her disease 12 months after surgery. Both cases 1 and 2 were stage IB and alive with no evidence of disease for 28 months and 9 years, respectively.

CONCLUSION

Although the prognosis of small cell carcinoma of endometrium is poor, early detection of this disease may contribute to an improved prognosis.

Small cell carcinoma of the endometrium: report of three cases and literature review

Background

Small cell carcinoma of the endometrium is extremely rare.

Aim

We reported three cases of this rare tumor and reviewed the literature.

Cases

Case 1 was a 54-year-old woman and case 3 was a 58-year-old woman. Both patients presented with vaginal bleeding. Case 2, a 53-year-old woman, had no symptoms and had a vaginal-cervical smear suspicious for malignancy. All patients underwent surgery and their tumors originated in the endometrium. In all three cases, pathological examination revealed small cell carcinoma of endometrium, and immunohistochemical reactivity for one or more neuroendocrine markers was found in all cases. Under electron microscopy in case 2 and case 3, dense core granules in the cytoplasm of tumor cells were found only in case 3. Case 3 was stage IIIA and died of her disease 12 months after surgery. Both cases 1 and 2 were stage IB and alive with no evidence of disease for 28 months and 9 years, respectively.

Conclusion

Although the prognosis of small cell carcinoma of endometrium is poor, early detection of this disease may contribute to an improved prognosis.

Reduced airway inflammation and remodeling in parallel with mucin 5AC protein expression decreased by s-carboxymethylcysteine, a mucoregulant, in the airways of rats exposed to sulfur dioxide

BACKGROUND

Human obstructive airway diseases are histopathologically characterized by inflammatory cell infiltration, goblet cell hyperplasia, and mucus hypersecretion in airways. We prepared a rat model of airway injury by exposure of sulfur dioxide (SO2) and then evaluated the effects of S-carboxymethylcysteine (S-CMC), a mucoregulant.

METHODS

Rats were exposed to SO2 gas for 44 days and orally given S-CMC at 250 mg/kg, twice daily, from 21 to 44 days of exposure for histopathological and immunohistochemical evaluation.

RESULTS

SO2 exposure induced inflammatory cell infiltration and mucus cell increase in rat airways. S-CMC treatment significantly decreased this inflammatory cell infiltration in proximal and peripheral airways. Morphometrically, SO2 exposure significantly increased the number of Alcian blue (pH 2.5)- and periodic acid-Schiff (AB/PAS)-positive cells in rat airways (11.8 x 10(-2) cell/nuclear profiles per micrometer basement membrane) compared to normal rat airways (1.6 x 10(-2) cell/nuclear profiles per micrometer basement membrane). S-CMC treatment significantly decreased the number of AB/PAS-positive cells (4.4 x 10(-2) cell/nuclear profiles per micrometer basement membrane, p < 0.01 vs. SO2-exposed rats). Immunohistochemically, SO2 exposure increased the expression of mucin 5AC (MUC5AC) protein in the airway epithelium of rats, but S-CMC treatment inhibited the increase.

CONCLUSIONS

The increased mucus cells and MUC5AC protein expression seem associated with SO2-induced airway inflammation in rats. The fact that S-CMC suppresses airway inflammation and the increase in mucus cells and MUC5AC protein expression suggests that this mucoregulant may be advantageous in the treatment of inflammatory airway diseases with goblet cell hyperplasia.

[Psychological stress and rewarding effect of alcohol]

It has long been postulated that an interaction between ethanol and stress may play an important role in the etiology of alcoholism. In the present review, we focused on an interaction between ethanol and stress in the mechanism of psychological dependence on ethanol. Ethanol with conditioned fear stress (CFS), but not without the stress, induced a significant place preference. These results suggest that psychological stress may play an important role in the rewarding effect of ethanol. It has been hypothesized that activation of the mesolimbic dopamine system mediated by the endogenous opioid system may be particularly important in the rewarding mechanism of ethanol. It appeared that mu- and delta-opioid receptors might play critical roles in the development of the rewarding effect of ethanol under the stress. Under psychological stress, the rewarding effect of ethanol through the activation of mu- and/or delta-opioid receptors was found to results the activation of dopamine D1 and/or D2 receptors. Additionally, a subtype of serotonin (5-HT) receptors, 5-HT3 receptor, was shown to be involved in the rewarding mechanism of ethanol through the activation of mu- and delta-opioid receptors. In conclusion, psychological stress may be an important factor in the development of the rewarding effect of ethanol and may potentiate the rewarding mechanism. 5-HT3 receptor, is likely to be involved in the rewarding mechanism of ethanol under stress. Dopamine D1 and D2 receptors may also be implicated in the rewarding mechanism of ethanol under stress.

TUCAN, an antiapoptotic caspase-associated recruitment domain family protein overexpressed in cancer

Caspase-associated recruitment domains (CARDs) are protein interaction domains that participate in activation or suppression of CARD-carrying members of the caspase family of apoptosis-inducing proteases. A novel CARD-containing protein was identified that is overexpressed in some types of cancer and that binds and suppresses activation of procaspase-9, which we term TUCAN (tumor-up-regulated CARD-containing antagonist of caspase nine). The CARD domain of TUCAN selectively binds itself and procaspase-9. TUCAN interferes with binding of Apaf1 to procaspase-9 and suppresses caspase activation induced by the Apaf1 activator, cytochrome c. Overexpression of TUCAN in cells by stable or transient transfection inhibits apoptosis and caspase activation induced by Apaf1/caspase-9-dependent stimuli, including Bax, VP16, and staurosporine, but not by Apaf1/caspase-9-independent stimuli, Fas and granzyme B. High levels of endogenous TUCAN protein were detected in several tumor cell lines and in colon cancer specimens, correlating with shorter patient survival. Thus, TUCAN represents a new member of the CARD family that selectively suppresses apoptosis induced via the mitochondrial pathway for caspase activation.

Photolytic behavior of polycyclic aromatic hydrocarbons in diesel particulate matter deposited on the ground

To clarify the photolytic behavior of polycyclic aromatic hydrocarbons (PAHs) in diesel particulate matter (DPM) deposited on the ground, we determined the rate constants and half-lives for the photodegradation of benzo[a]pyrene (BaPy), phenanthrene (Phe), fluoranthene (Flrt), pyrene (Py), and chrysene (Ch) in air for three probable cases: (1) DPM is placed on an inert surface, (2) DPM is mixed with soil, and (3) PAHs are leached from DPM and adsorbed to soil. We found that BaPy and Phe degraded relatively quickly in case 1. However, in case 2, these PAHs degraded more slowly due to the effect of the presence of soil. Flrt, Py, and Ch were stable. In case 3, photodegradation of adsorbed PAHs in soil was strongly inhibited as a function of soil depth. Although these findings were obtained at extreme light intensities, they may occur under real world conditions. Conversion factors for obtaining rate constants and half-lives for PAHs on the ground under sunlight are presented. We conclude that under the average intensity of sunlight in Tokyo, photodegradation of PAHs in DPM deposited on an inert surface is very slow.

TRAF1 is a substrate of caspases activated during tumor necrosis factor receptor-alpha-induced apoptosis

TRAF family proteins are signal-transducing adapter proteins that interact with the cytosolic domains of tumor necrosis factor (TNF) family receptors. Here we show that TRAF1 (but not TRAF2-6) is cleaved by certain caspases in vitro and during TNF-alpha- and Fas-induced apoptosis in vivo. (160)LEVD(163) was identified as the caspase cleavage site within TRAF1, generating two distinct fragments. Significant enhancement of TNF receptor-1 (CD120a)- and, to a lesser extent, Fas (CD95)-mediated apoptosis was observed when overexpressing the C-terminal TRAF1 fragment in HEK293T and HT1080 cells. The same fragment was capable of potently suppressing TNF receptor-1- and TRAF2-mediated nuclear factor-kappaB activation in reporter gene assays, providing a potential mechanism for the enhancement of TNF-mediated apoptosis. Cell death induced by other death receptor-independent stimuli such as cisplatin, staurosporine, and UV irradiation did not result in cleavage of TRAF1, and overexpression of the C-terminal TRAF1 fragment did not enhance cell death in these cases. TRAF1 cleavage was markedly reduced in cells that contain little procaspase-8 protein, suggesting that this apical protease in the TNF/Fas death receptor pathway is largely responsible. These data identify TRAF1 as a specific target of caspases activated during TNF- and Fas-induced apoptosis and illustrate differences in the repertoire of protease substrates cleaved during activation of different apoptotic pathways.

New diagnostic approach for ocular tuberculosis by ELISA using the cord factor as antigen

BACKGROUND/AIMS

Diagnosis of ocular tuberculosis is difficult, particularly the retinal vasculitis type, because most cases occur without concurrent active pulmonary tuberculosis. Recently, it has been reported that detection of antibodies against purified cord factor (trehalose-6,6'-dimycolate, TDM), the best studied, most antigenic, and most abundant cell wall component of tubercule bacilli, is very useful for rapid serodiagnosis of pulmonary tuberculosis. In this study, an attempt was made to evaluate whether the detection of anticord factor antibody is also useful for diagnosis of ocular tuberculosis and the necessity of antituberculous therapy for tuberculous retinochoroiditis was discussed.

METHODS

Cases consisted of 15 patients with uveitis and retinal vasculitis, nine patients with presumed ocular tuberculosis, three patients with sarcoidosis, and three patients with Behçet's disease. IgG antibodies against purified cord factor prepared from Mycobacterium tuberculosis H37Rv were detected by enzyme linked immunosorbent assay.

RESULTS

All cases of clinically presumed ocular tuberculosis were positive, whereas all of the cases of sarcoidosis or Behçet's disease were negative for anticord factor antibodies. When the anticord factor antibody titres were compared on the basis of the presence or absence of previous antituberculosis chemotherapy, the mean anticord factor antibody titre of the untreated group showed a tendency to be higher than in the treated group, but not significantly (p=0.07).

CONCLUSIONS

The detection of anticord factor antibody may be useful to support the diagnosis of ocular tuberculosis. Additionally, a positive result for anticord factor antibody may indicate that tubercule bacilli are present in some organ(s) of the patient even in the absence of active systemic disease.

Dose and dose-rate effects of X rays and fission neutrons on lymphocyte apoptosis in p53(+/+) and p53(-/-) mice

Following the exposure of mice to X rays or fission neutrons, the frequency (F) of apoptosis was measured after 4 h, and the weight loss or lymphocyte content loss in the thymus and spleen was measured after 24 h. In p53(+/+) mice, F increased linearly with the dose (D (Gy)) and the induced rate per Gy of F (detected by TUNEL staining) was 0.05 and 0.23 for X rays and fission neutrons, respectively. Therefore, the RBE of fission neutrons was 4.6 for apoptosis induction. This indicates that radiation-induced apoptosis is mostly due to double strand breaks (DSBs) in DNA because we previously obtained almost the same RBE value of fission neutrons for the induction of crossover mutations in Drosophila melanogaster, which arise from the recombinational repair of DSBs. In p53(+/+) mice, decreases in the organ weight and the lymphocyte content were observed for the thymus and the spleen 24 h after X-irradiation. These atrophic changes in the thymus and the spleen quantitatively corresponded to the total apoptotic cell deaths occurring in them. However, in p53(-/-) mice, no vigorous apoptosis was induced after X-irradiation, and hyperplastic changes in the weight and the lymphocyte content appeared in the thymus and the spleen 24 h after X-irradiation. In p53(+/+) mice, there was no difference in the induced rate per Gy of reduction in the surviving fraction of lymphocytes between acute (0.4 Gy/min) and chronic (3 mGy/min) gamma-irradiations. Namely, radiation-induced apoptosis in lymphocytes is a dose-rate independent event.

p53 suppresses the c-Myb-induced activation of heat shock transcription factor 3

Expression of heat shock proteins (HSPs) is controlled by heat shock transcription factors (HSFs). Vertebrates express multiple HSFs whose activities may be regulated by distinct signals. HSF3 is specifically activated in unstressed proliferating cells by direct binding to the c-myb proto-oncogene product (c-Myb), which plays an important role in cellular proliferation. This suggests that the c-Myb-induced HSF3 activation may contribute to the growth-regulated expression of HSPs. Here we report that the p53 tumor suppressor protein directly binds to HSF3 and blocks the interaction between c-Myb and HSF3. In addition, p53 stimulates the degradation of c-Myb through a proteasome-dependent mechanism, which is, at least partly, mediated by induction of Siah in certain types of cells. Induction of p53 by a genotoxic reagent in DT40 cells disrupts the HSF3-c-Myb interaction and down-regulates the expression of certain HSPs. Mutated forms of p53 found in certain tumors did not inhibit c-Myb-induced HSF3 activation. The regulation of HSF3 activity by c-Myb and p53 sheds light on the molecular events that govern HSP expression during cellular proliferation and apoptosis.

The Drosophila tumor necrosis factor receptor-associated factor-1 (DTRAF1) interacts with Pelle and regulates NFkappaB activity

A member of the tumor necrosis factor (TNF) receptor-associated factor (TRAF) family was identified in Drosophila. DTRAF1 contains 7 zinc finger domains followed by a TRAF domain, similar to mammalian TRAFs and other members of the family identified in data bases from Caenorhabditis elegans, Arabidopsis, and Dictyostelium. Analysis of DTRAF1 binding to different members of the human TNF receptor family showed that this protein can interact through its TRAF domain with the p75 neurotrophin receptor and weakly with the lymphotoxin-beta receptor. DTRAF1 can also self-associate and binds to human TRAF1, TRAF2, and TRAF4. Interestingly, DTRAF1 interacts with human cIAP-1 and cIAP-2 but not with Drosophila DIAP-1 and -2. By itself, DTRAF1 did not induce significant NFkappaB activation when overexpressed in mammalian cells, although it specifically increased NFkappaB induction by TRAF6. In contrast, TRAF2-mediated NFkappaB induction was partially inhibited by DTRAF1. Mutants of DTRAF1 lacking the N-terminal region inhibited NFkappaB induction by either TRAF2 or TRAF6. DTRAF1 specifically associated with the regulatory N-terminal domain of Pelle, a Drosophila homolog of the human kinase interleukin-1 receptor-associated kinase (IRAK). Interestingly, though Pelle and DTRAF1 individually were unable to induce NFkappaB in a human cell line, co-expression of Pelle and DTRAF1 resulted in significant NFkappaB activity. Interactions of DTRAF1 with human TRAF-, TNF receptor-, and IAP-family proteins imply strong evolutionary conservation of TRAF protein structure and function throughout Metazoan evolution.

Involvement of mu-opioid receptor in the salsolinol-associated place preference in rats exposed to conditioned fear stress

BACKGROUND

Salsolinol, a condensation product of dopamine with acetaldehyde (the initial oxidation product of ethanol), has long been discussed as an endogenous opioid system-activating factor contributing to the etiology of alcoholism. Moreover, psychological stress has been considered to play an important role in the development of alcoholism.

METHODS

Male Sprague Dawley rats were subjected to conditioned fear stress (at 24 hr after electric footshock exposure), and then salsolinol or saline was injected intraperitoneally. For conditioning, rats were immediately confined to the nonpreferred compartment after salsolinol injection and to the preferred compartment after saline injection on alternate days. This conditioning session was repeated twice daily (for 8 days). Test session was carried out 1 day after the last conditioning session.

RESULTS

Salsolinol [10 mg/kg, but not 1, 3, or 30 mg/kg, intraperitoneally (ip)] without conditioned fear stress induced a slight, but significant, place preference. In contrast, salsolinol (1, 3, and 10 mg/kg, ip) with conditioned fear stress induced a marked and significant place preference. The nonselective opioid receptor antagonist naloxone hydrochloride (which can pass into the brain), but not the nonselective peripheral opioid receptor antagonist naloxone methiodide (which cannot pass into the brain), significantly attenuated the salsolinol (3 mg/kg, ip)-induced place preference under conditioned fear stress. Moreover, the selective mu-opioid receptor antagonist beta-funaltrexamine significantly attenuated the salsolinol-induced place preference. Furthermore, 0.3 mg/kg salsolinol (which produced no significant place preference) combined with the mu-opioid receptor agonist morphine [0.1 mg/kg, subcutaneously (sc)], at the dose which alone produced no significant place preference, produced a marked and significant place preference. Both naloxone hydrochloride and beta-funaltrexamine significantly attenuated the salsolinol plus morphine-induced place preference.

CONCLUSIONS

Salsolinol may have some rewarding effect, and its rewarding effect may be potentiated by psychological stress. In addition, the rewarding effect of salsolinol especially under psychological stress may involve the endogenous central opioid system, i.e., mu-opioid receptor.

A randomised control study of partial liquid ventilation after airway lavage with exogenous surfactant in a meconium aspiration syndrome animal model

AIMS

To test the hypothesis that lavage with exogenous surfactant before partial liquid ventilation in meconium aspiration syndrome (MAS) would improve debris removal, and therefore the effectiveness of partial liquid ventilation.

METHODS

12 newborn piglets were randomised into 4 groups, partial liquid ventilation or gas ventilation, with and without surfactant lavage. Physiological and blood gas data were compared between groups by analysis of variance.

RESULTS

Arterial oxygen pressure (PaO(2)) was improved in the group treated with surfactant lavage when compared with the group not receiving surfactant. PaO(2) in the group receiving surfactant lavage followed by partial liquid ventilation was further improved when compared with the group treated with surfactant lavage followed by gas ventilation and the group receiving partial liquid ventilation alone.

CONCLUSION

The effectiveness of partial liquid ventilation in MAS might be enhanced by pretreatment with exogenous surfactant bronchial lavage.

Ethanol, but not the anxiolytic drugs buspirone and diazepam, produces a conditioned place preference in rats exposed to conditioned fear stress

The present study was designed to investigate the role of an anxiolytic effect in the development of a drug-associated place preference in rats exposed to conditioned fear stress, using the conditioned place-preference paradigm. The administration of a low dose of ethanol (300 mg/kg, IP) and the anxiolytic drugs, buspirone (1 and 2 mg/kg, IP) and diazepam (1.25 and 2.5 mg/kg, IP), did not produce a place preference in rats that were not exposed to conditioned fear stress. In rats that were exposed to conditioned fear stress, ethanol produced a significant place preference, while buspirone and diazepam failed to produce a place preference. In addition, ethanol, buspirone, and diazepam produced no place preference in rats treated with an anxiogenic dose of pentylenetetrazole (20 mg/kg, IP). A significant decrease in locomotor activity was observed in rats exposed to conditioned fear stress. Ethanol, but not buspirone and diazepam, significantly recovered or increased locomotor activity in rats exposed to conditioned fear stress. Further, the locomotor-stimulating effect of ethanol was markedly enhanced by repeated exposure to conditioned fear stress. These results suggest that the stimulating effect may be strongly related to the development of the rewarding effect of a low dose of ethanol under psychological stress, and that the conditioned place preference paradigm with conditioned fear stress may be useful for studying the rewarding mechanism of ethanol with regard to the interaction between ethanol and psychological stress.

Differential requirements for tumor necrosis factor receptor-associated factor family proteins in CD40-mediated induction of NF-kappaB and Jun N-terminal kinase activation

CD40 is a member of the tumor necrosis factor receptor family that mediates a number of important signaling events in B-lymphocytes and some other types of cells through interaction of its cytoplasmic (ct) domain with tumor necrosis factor receptor-associated factor (TRAF) proteins. Alanine substitution and truncation mutants of the human CD40ct domain were generated, revealing residues critical for binding TRAF2, TRAF3, or both of these proteins. In contrast to TRAF2 and TRAF3, direct binding of TRAF1, TRAF4, TRAF5, or TRAF6 to CD40 was not detected. However, TRAF5 could be recruited to wild-type CD40 in a TRAF3-dependent manner but not to a CD40 mutant (Q263A) that selectively fails to bind TRAF3. CD40 mutants with impaired binding to TRAF2, TRAF3, or both of these proteins completely retained the ability to activate NF-kappaB and Jun N-terminal kinase (JNK), implying that CD40 can stimulate TRAF2- and TRAF3-independent pathways for NF-kappaB and JNK activation. A carboxyl-truncation mutant of CD40 lacking the last 32 amino acids required for TRAF2 and TRAF3 binding, CD40(Delta32), mediated NF-kappaB induction through a mechanism that was suppressible by co-expression of TRAF6(DeltaN), a dominant-negative version of TRAF6, but not by TRAF2(DeltaN), implying that while TRAF6 does not directly bind CD40, it can participate in CD40 signaling. In contrast, TRAF6(DeltaN) did not impair JNK activation by CD40(Delta32). Taken together, these findings reveal redundancy in the involvement of TRAF family proteins in CD40-mediated NF-kappaB induction and suggest that the membrane-proximal region of CD40 may stimulate the JNK pathway through a TRAF-independent mechanism.

Involvement of dopamine D(1) and D(2) receptors in the ethanol-associated place preference in rats exposed to conditioned fear stress

The present study was designed to investigate: (1) the involvement of dopamine D(1) and D(2) receptors, and (2) the roles of these receptors and endogenous opioid systems (endorphinergic and enkephalinergic systems) in the ethanol-induced place preference in rats exposed to conditioned fear stress using the conditioned place preference paradigm. The administration of ethanol (300 mg/kg, i.p.) induced a significant place preference. The selective D(1) receptor antagonist R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4, 5-tetrahydro-1H3-benzazepine)hydrochloride (SCH23390; 0.01 and 0.03 mg/kg, s.c.) and the selective D(2) receptor antagonist S(-)-5-(aminosulfonyl)-N-[(1-ethyl-2-pyrrolidinyl)-methyl]-2- methoxybenzamide (sulpiride; 20 and 40 mg/kg, s.c.) significantly attenuated the ethanol-induced place preference. The administration of ethanol (75 mg/kg, i.p.) tended to produce a place preference, but this effect was not significant. SCH23390 (0.03 mg/kg, s.c.) and sulpiride (40 mg/kg, s.c.) significantly attenuated the enhancement of the ethanol (75 mg/kg, i.p.)-induced place preference produced by the mu-opioid receptor agonist morphine (0.1 mg/kg, s.c.). In addition, SCH23390 (0.03 mg/kg, s.c.) also significantly attenuated the enhancement of the ethanol (75 mg/kg, i.p.)-induced place preference produced by the selective delta-opioid receptor agonist 2-methyl-4aalpha-(3-hydroxyphenyl)-1,2,3,4,4a,5,12, 12aalpha-octahydroquinolino[2,3,3,-g]isoquinoline (TAN-67; 20 mg/kg, s.c.). On the other hand, sulpiride (40 mg/kg) had no significant effect on the enhancement of the ethanol (75 mg/kg, i.p.)-induced place preference produced by TAN-67. These results suggest that D(1) and D(2) receptors may be involved in the rewarding mechanism of ethanol under psychological stress. In addition, D(1) receptors may participate in the rewarding effect of ethanol modulated by the activation of mu- and delta-opioid receptors, whereas D(2) receptors may participate in the rewarding effect of ethanol modulated by the activation of mu-opioid receptors, but not in that modulated by the activation of delta-opioid receptors.

Repeated acute hypoxia temporarily attenuates the ventilatory respiratory response to hypoxia in conscious newborn rats

We asked whether repeated hypoxic exposures during the early neonatal periods could affect the ventilatory control, such as the lung volume-dependent ventilatory inhibition (HBR), pulmonary ventilation (VE), and CO2 production (VCO2). Within each litter of rats, one group of pups (experimental group H) was exposed to 6% O2 (30-min duration twice a day from postnatal d 1 to 4). The other group (control group C) was exposed to air. At 5 d after birth, the HBR was triggered by lung inflation via negative body surface pressure (10 cm H2O). Measurements of VE and VCO2 were done by plethysmography and the inflow-outflow CO2 difference, respectively. At 2 wk of age, VE and VCO2 measurements were repeated by the barometric technique and the inflow-outflow CO2 difference, respectively. Each conscious pup was breathing normoxia (21% O2) and then hypoxia (10% O2). Results were as follows: 1) during normoxia, HBR was stronger and both VE and VCO2 were higher in H pups than in C pups; 2) during hypoxia, the HBR of C was as in normoxia, whereas that of H was increased above the normoxic value; 3) during hypoxia, C maintained VE, whereas H decreased it; 4) in hypoxia, VCO2 was reduced significantly in both groups; 5) at 2 wk of age, VE and VCO2 did not differ between H and C during normoxia or in response to 10% hypoxia. We conclude that in rat pups, repeated hypoxic episodes can modify the HBR and, at least temporarily, reduce the VE response to hypoxia with a decrease in VCO2. The findings are in agreement with the view that repeated hypoxic exposures in the neonatal period could interfere with the development of respiratory control and could possibly be involved in the mechanisms of neonatal apnea or sudden infant death syndrome.

Roles of 5-HT3 and opioid receptors in the ethanol-induced place preference in rats exposed to conditioned fear stress

The effect of the selective 5-HT3 receptor antagonist ondansetron on the ethanol-induced place preference in rats exposed to conditioned fear stress, which stimulates the release of endogenous opioid peptides (beta-endorphin and enkephalins), was investigated using the conditioned place preference paradigm. In addition, we also examined the effect of ondansetron on the ethanol-induced place preference enhanced by the administration of mu- and delta-opioid receptor agonists (exogenous opioids). The administration of ethanol (300 mg/kg, i.p.) induced a significant place preference in rats exposed to conditioned fear stress. Pretreatment with ondansetron (0.01 and 0.1 mg/kg, s.c.) effectively attenuated this ethanol-induced place preference. When the mu-opioid receptor agonist morphine (0.1 mg/kg, s.c.) or the selective delta-opioid receptor agonist 2-methyl-4a(alpha)-(3-hydroxyphenyl)-1,2,3,4,4a,5,12,12a(alpha)-octah ydroquinolino [2,3,3-g] isoquinoline (TAN-67; 20 mg/kg, s.c.) was administered in combination with 75 mg/kg ethanol (which tended to produce a place preference), the ethanol-induced place preference was significantly enhanced. The selective mu-opioid receptor antagonist beta-funaltrexamine at a dose of 10 mg/kg significantly attenuated the enhancement of the ethanol-induced place preference produced by morphine. Ondansetron (0.1 mg/kg, s.c.) also significantly attenuated the enhancement of the ethanol-induced place preference produced by morphine. Furthermore, the selective delta-opioid receptor antagonist naltrindole at a dose of 3 mg/kg significantly attenuated the enhancement of the ethanol-induced place preference produced by TAN-67. Ondansetron (0.1 mg/kg, s.c.) slightly, but significantly, attenuated the enhancement of the ethanol-induced place preference produced by TAN-67. These results suggest that 5-HT3 receptors may be involved in the rewarding mechanism of ethanol under psychological stress, and may play an important role in the rewarding effect of ethanol through the activation of mu- and delta-opioid receptors.

Different roles of mu-, delta- and kappa-opioid receptors in ethanol-associated place preference in rats exposed to conditioned fear stress

The present study was designed to investigate the role of the endogenous opioid system in the development of ethanol-induced place preference in rats exposed to conditioned fear stress (exposure to an environment paired previously with electric foot shock), using the conditioned place preference paradigm. The administration of ethanol (300 mg/kg, i.p.) with conditioned fear stress induced significant place preference. Naloxone (1 and 3 mg/kg, s.c.), a non-selective opioid receptor antagonist, significantly attenuated this ethanol-induced place preference. Moreover, the selective mu-opioid receptor antagonist beta-funaltrexamine (3 and 10 mg/kg, i.p.) and the selective delta-opioid receptor antagonist naltrindole (1 and 3 mg/kg, s.c.) significantly attenuated ethanol-induced place preference. In contrast, the selective kappa-opioid receptor antagonist nor-binaltorphimine (3 mg/kg, i.p.) significantly enhanced ethanol-induced place preference. Furthermore, 75 mg/kg ethanol (which tended to produce place preference) combined with the mu-opioid receptor agonist morphine (0.1 mg/kg, s.c.) or the selective delta-opioid receptor agonist 2-methyl-4aalpha-(3-hydroxyphenyl)-1,2,3,4,4a,5,12,12aalpha- octahydroquinolino [2,3,3,-g] isoquinoline (TAN-67; 20 mg/kg, s.c.), at doses which alone did not produce place preference, produced significant place preference. However, co-administration of the selective kappa-opioid receptor agonist trans-3,4-dichloro-N-(2-(1-pyrrolidinyl)cyclohexyl)benzenacetamide methanesulfonate (U50,488H; 0.3 and 1 mg/kg, s.c.) with ethanol (300 mg/kg, i.p.) dose dependently attenuated ethanol-induced place preference. Moreover, conditioned fear stress shifted the response curve for the aversive effect of U50,488H to the left. These results suggest that mu- and delta-opioid receptors may play critical roles in the rewarding mechanism of ethanol, and that kappa-opioid receptors may modulate the development of the rewarding effect of ethanol under psychological stress.

Thyrsiferyl 23-acetate and its derivatives induce apoptosis in various T- and B-leukemia cells

Thyrsiferyl 23-acetate (TF-23A), a cytotoxic compound from marine red alga, induced a rapid cell death in various leukemic T- and B-cell lines. During incubation of Jurkat cells with TF-23A, condensation and fragmentation of nuclei occurred and clusters composed of uneven small cellular particles were formed. Concentration- and time-dependent DNA fragmentation was also induced by the incubation of the cells with TF-23A. These results demonstrate that the TF-23A-induced cell death follows a typical apoptotic process. The TF-23A-induced apoptosis was prevented by fetal calf serum and insulin, but not by EGF or PDGF. TF-23A and its several analogous compounds showed apoptosis-inducing activity. However, only TF-23A out of these compounds showed an inhibitory activity for protein phosphatase 2A, PP2A. These results strongly suggest that a structure of TF-23A involved in induction of apoptosis is different from that involved in the PP2A inhibition.

Involvement of mu- and delta-opioid receptors in the ethanol-associated place preference in rats exposed to foot shock stress

The purpose of this study was to establish the ethanol-induced place preference in rats exposed to foot shock stress using the conditioned place preference paradigm. We also investigated the role of the endogenous opioid system in the development of the ethanol-induced place preference. The administration of ethanol (300 mg/kg, i.p.) with foot shock stress, but not without such stress, induced a marked and significant place preference. Naloxone (1 and 3 mg/kg, s.c.), a non-selective opioid receptor antagonist, significantly attenuated the ethanol-induced place preference. Moreover, the selective mu-opioid receptor antagonist beta-funaltrexamine (3 and 10 mg/kg, i.p.) and selective delta-opioid receptor antagonist naltrindole (1 and 3 mg/kg, s.c.), but not the selective kappa-opioid receptor antagonist nor-binaltorphimine (1 and 3 mg/kg, i.p.), significantly attenuated the ethanol-induced place preference. Furthermore, 150 mg/kg ethanol (which tended to produce a place preference, although not significantly) combined with each dose (that did not produce a place preference) of the mu-opioid receptor agonist morphine (0.1 mg/kg, s.c.) or selective delta-opioid receptor agonist 2-methyl-4aalpha-(3-hydroxyphenyl)-1,2,3,4,4a,5,12, 12aalpha-octahydroquinolino [2,3,3-g] isoquinoline (TAN-67; 20 mg/kg, s.c.), but not the selective kappa-opioid receptor agonist trans-3, 4-dichloro-N-(2-(1-pyrrolidinyl)cyclohexyl)benzenacetamide methanesulfonate (U50,488H; 1 mg/kg, s.c.), produced a significant place preference. These data indicate that stress may be important for development of the rewarding effect of ethanol, and that mu- and delta-opioid receptors may be involved in the rewarding mechanism of ethanol under stressful conditions.

p53-inducible human homologue of Drosophila seven in absentia (Siah) inhibits cell growth: suppression by BAG-1

The Drosophila seven in absentia (sina) gene is required for R7 photoreceptor cell formation during Drosophila eye development, where it functions within the Ras/Raf pathway and targets other proteins for degradation via associations with a ubiquitin-conjugating enzyme. Recently, a mammalian sina homologue was reported to be a p53-inducible gene in a myeloid leukemia cell line. To explore the function of human SINA-homologous (Siah) proteins, expression plasmids encoding Siah-1A were transiently transfected into 293 epithelial cells and GM701 fibroblast cells, resulting in growth arrest without induction of apoptosis. We discovered that BAG-1, a ubiquitin-like Hsp70/Hsc70-regulating protein, is a negative regulator of Siah-1A. Siah-1A was identified as a BAG-1-binding protein via yeast two-hybrid methods. Specific interaction of BAG-1 with Siah-1A was also demonstrated by in vitro binding experiments using glutathione S-transferase fusion proteins and co-immunoprecipitation studies. Siah-1A-induced growth arrest in 293 and GM701 cells was abolished by co-transfection of wild-type BAG-1 with Siah-1A but not by a C-terminal deletion mutant of BAG-1 that fails to bind Siah-1A. Over-expression of BAG-1 significantly inhibited p53-induced growth arrest in 293 cells without preventing p53 transactivation of reporter gene plasmids. BAG-1 also prevented growth arrest following UV-irradiation-induced genotoxic injury without interfering with accumulation of p53 protein or p21(waf-1) expression. BAG-1 functions downstream of p53-induced gene expression to inhibit p53-mediated suppression of cell growth, presumably by suppressing the actions of Siah-1A. We suggest that Siah-1A may be an important mediator of p53-dependent cell-cycle arrest and demonstrate that Siah-1A is directly inhibited by BAG-1.

Different moieties of tautomycin involved in protein phosphatase inhibition and induction of apoptosis

The effects of tautomycin and its derivatives on protein phosphatases PP1 and PP2A and their apoptosis-inducing activity toward human leukemia Jurkat cells were examined, and the relationship between chemical structure and function was discussed. Among the compounds we examined, tautomycin was the most potent inhibitor and the most effective inducer of apoptosis. It inhibited PP1 and PP2A enzymatic activity concentration-dependently with IC50 values of 20 and 75 pM, respectively, in the presence of 0.01% Brij-35, and an LC50 value of 1 microM. Esterification of the anhydride moiety of tautomycin markedly increased the IC50 for the protein phosphatases. The C1'-C7' fragment of tautomycin had no inhibitory effect, but the fragment containing the C22-C26 moiety was inhibitory. These results suggest that the C22-C26 moiety is essential for inhibition of protein phosphatase activity and that the anhydride moiety enhances the inhibition. However, the esterification of the anhydride did not decrease, nor did the inclusion of the C22-C26 moiety increase the apoptosis-inducing activity. On the other hand, the C1-C18 moiety of tautomycin was essential for induction of apoptosis, and the conformation and the arrangement of functionalities of the C18-C26 carbon chain affected the apoptosis activity. However, modification of C1-C18, C1-C21, or C1-C26 compounds had little effect on phosphatase inhibitory activity. Our results strongly suggest that different moieties of tautomycin are involved in protein phosphatase inhibition and induction of apoptosis.

Conditioned fear stress induces ethanol-associated place preference in rats

The purpose of the present study was to establish ethanol-induced place preference under conditioned fear stress (exposure to an environment paired previously with electric foot shock) in rats by using the conditioned place preference paradigm. The administration of ethanol (300 mg/kg, i.p.) with conditioned fear stress, but not without conditioned fear stress, induced a marked and significant place preference. Furthermore, additional exposure to conditioned fear stress immediately before the post-conditioning test further enhanced the development of ethanol-induced place preference. These results suggest that psychological stress may play an important role in the development of ethanol-induced place preference, and the present method may be useful for studying the mechanism of the rewarding effect of ethanol.

Alterations in type-1 serine/threonine protein phosphatase PP1alpha in response to B-cell receptor stimulation

In response to stimulation of B-cells through cell surface IgM, the activity of the serine/threonine protein phosphatase PP1, but not PP2A, was transiently decreased and reached a minimum 10-20 min after the stimulation. The decrease was more profound in the immature B-cell line WEHI-231, than in the mature B-cell line BAL-17. Under these conditions, PP1alpha, an isoform of PP1, showed unique alterations in the patterns of several spots with distinct isoelectic points in the Western blot after two-dimensional electrophoresis, whereas another isoform, PP1delta, did not show any alteration. PP1gamma1 and PP1gamma2 were not detected in B-cells. Similar alterations in these spots were observed in B-cells stimulated by PMA. When partially purified PP1 consisting of PP1alpha and PP1delta was incubated with [gamma-32P]ATP and PKC, radioactive spots of PP1alpha could be detected, but no spot of PP1delta was detected. Because differences in sequence among PP1 isoforms are mostly restricted to their C-terminals, phosphorylation rates of the C-terminal peptides containing the PKC-phosphorylation motif were compared. The C-terminal peptide of PP1alpha is a better substrate for PKC than those of PP1gamma1 and PP1gamma2, and is phosphorylated at the serine residue corresponding to Ser-325 of PP1alpha. The corresponding C-terminal region of PP1delta does not contain the phosphorylation site. On the other hand, there was a large difference in subcellular distribution of PP1delta, but not PP1alpha, between immature and mature B-cells. From these results, it was strongly suggested that PP1alpha is involved, via phosphorylation by PKC, in the regulation of signal transduction in response to the stimulation of B-cells through cell surface IgM.

BAG-1 modulates the chaperone activity of Hsp70/Hsc70

The 70 kDa heat shock family of molecular chaperones is essential to a variety of cellular processes, yet it is unclear how these proteins are regulated in vivo. We present evidence that the protein BAG-1 is a potential modulator of the molecular chaperones, Hsp70 and Hsc70. BAG-1 binds to the ATPase domain of Hsp70 and Hsc70, without requirement for their carboxy-terminal peptide-binding domain, and can be co-immunoprecipitated with Hsp/Hsc70 from cell lysates. Purified BAG-1 and Hsp/Hsc70 efficiently form heteromeric complexes in vitro. BAG-1 inhibits Hsp/Hsc70-mediated in vitro refolding of an unfolded protein substrate, whereas BAG-1 mutants that fail to bind Hsp/Hsc70 do not affect chaperone activity. The binding of BAG-1 to one of its known cellular targets, Bcl-2, in cell lysates was found to be dependent on ATP, consistent with the possible involvement of Hsp/Hsc70 in complex formation. Overexpression of BAG-1 also protected certain cell lines from heat shock-induced cell death. The identification of Hsp/Hsc70 as a partner protein for BAG-1 may explain the diverse interactions observed between BAG-1 and several other proteins, including Raf-1, steroid hormone receptors and certain tyrosine kinase growth factor receptors. The inhibitory effects of BAG-1 on Hsp/Hsc70 chaperone activity suggest that BAG-1 represents a novel type of chaperone regulatory proteins and thus suggest a link between cell signaling, cell death and the stress response.

The interconversion of protein phosphatase 2A between PP2A1 and PP2A0 during retinoic acid-induced granulocytic differentiation and a modification on the catalytic subunit in S phase of HL-60 cells

Alterations in protein phosphatase 2A (PP2A) during retinoic acid-induced differentiation of HL-60 cells have been investigated. PP2A activity of HL-60 cells for phosphorylated myelin basic protein showed a sharp and transient increase after 18-h treatment with 1 microM retinoic acid, which corresponded to G1/S boundary of the cell cycle. This PP2A of the 18-h treated cells was eluted from a DEAE-Sepharose column with 0.13 M NaCl, while PP2A from control cells was eluted with 0.23 M NaCl. The phosphorylase phosphatase activity of PP2A in the 0.13 M eluate was greatly enhanced in the presence of protamine compared with that of the later eluting PP2A. Immunoblot analyses with antisera against B' and B alpha subunits showed that the PP2A in the 0.13 M NaCl eluate from 18-h retinoic acid-treated cells was PP2A0 (AC-B'), whereas the PP2A eluted with 0.23 M NaCl from 24-h retinoic acid-treated cells and 0-, 18-, and 24-h control cells was PP2A1 (AC-B alpha). These results strongly suggest that PP2A undergoes a transient and reversible interconversion of holoenzyme forms during the initial stage of retinoic acid-induced granulocytic differentiation. PP2A activity assayed after dissociation of the catalytic subunit, for phosphorylase as substrate, showed a sharp and transient decrease in S phase of HL-60 cells irrespective of the presence or absence of retinoic acid. Immunoblot analyses with antisera against C-terminus and N-terminus of the catalytic subunit of PP2A suggested that a modification at the C-terminus is responsible for the decrease in PP2A activity. Immunoreactivity to the C-terminal antibody was restored after treatments of the S-phase extract with alkali or ethanol, the conditions which remove the methyl group from the C-terminus. These results suggest that the C-terminus of PP2A catalytic subunit is transiently methylated in S phase of HL-60 cells.

Gene expressions and activities of protein phosphatases 1 alpha, 2A and 2C in hepatocarcinogenesis and regeneration after partial hepatectomy

The mRNA levels of protein phosphatases (PP) 1 alpha, 2A, and 2C were determined both in hepatocarcinogenesis and in liver regeneration. In the precancerous stage and during regeneration, the mRNA levels of PP1 alpha, PP2A, and PP2C were markedly increased compared with those in normal livers. In primary hepatomas, all three of these mRNA levels were decreased to the control levels. In poorly differentiated hepatomas, however, only PP1 alpha mRNA was specifically increased, in contrast to PP2A and PP2C, which were at the control levels or below. While PP1 activity in the non-nuclear fraction of partially hepatectomized livers was nearly constant, the activity in nuclei was increased about 2.5-fold over control levels at 12 h after partial hepatectomy, the time that corresponds to the G1 to S transition in the cell cycle of hepatocytes. On the other hand, PP2A activity in both fractions was nearly constant throughout. These results appear to suggest some involvement of protein phosphatases in regulation of hepatocyte proliferation.