Traumatic deltoid rupture caused by seatbelt during a traffic accident: a case report

A right-handed 53-year-old man presented with a subcutaneous bruise on his right shoulder caused by a seatbelt during a traffic accident. He had no history of shoulder pain or hydrocortisone injections. The contour of the anterior deltoid was deformed and its belly was retracted distally. The active range of movement of the shoulder was limited to 120 degrees and the strength weakened to 3/5. Magnetic resonance imaging demonstrated detachment of the anterior fibres of the deltoid. Surgical repair of the deltoid and supraspinatus tendon was performed 2 months later using a pull-out suture technique. After 12 months of follow-up, the patient had returned to work without any problems. Both the range of movement and muscle strength had recovered completely.

PAC1 receptor localization in a model nervous system: light and electron microscopic immunocytochemistry on the earthworm ventral nerve cord ganglia

The presence and pattern of pituitary adenylate cyclase activating polypeptide (PACAP) type I (PAC1) receptors were identified by means of pre- and post-embedding immunocytochemical methods in the ventral nerve cord ganglia (VNC) of the earthworm Eisenia fetida. Light and electron microscopic observations revealed the exact anatomical positions of labeled structures suggesting that PACAP mediates the activity of some interneurons, a few small motoneurons and certain sensory fibers that are located in ventrolateral, ventromedial and intermediomedial sensory longitudinal axon bundles of the VNC ganglia. No labeling was located on large interneuronal systems such as dorsal medial and lateral giant axon systems and ventral giant axons. At the ultrastructural level labeling was mainly restricted to endo- and plasma membranes showing characteristic unequal distribution in various neuron parts. An increasing abundance of PAC1 receptors located on both rough endoplasmic reticulum and plasma membranes was seen from perikarya to neural processes, indicating that intracellular membrane traffic might play a crucial role in the transportation of PAC1 receptors. High number of PAC1 receptors was found in both pre- and postsynaptic membranes in addition to extrasynaptic sites suggesting that PACAP acts as neurotransmitter and neuromodulator in the earthworm nervous system.

New scaffold for recombinant human bone morphogenetic protein-2

A bioactive and resorbable scaffold is necessary to exhibit the osteoinductive potency of recombinant human bone morphogenetic protein-2 (rhBMP-2). In a previous study, we found that synthetic octacalcium phosphate (OCP) enhances bone regeneration and is replaced by newly formed bone after it is resorbed. We hypothesized that OCP may be useful as an effective scaffold for rhBMP-2 to enhance bone regeneration. To test this hypothesis, the present study was designed to investigate whether an OCP/BMP composite implant could more effectively enhance bone regeneration. A critical-sized defect was made in a rat calvarium and 1. 15 mg of OCP combined with 10 microg of rhBMP-2 (OCP/BMP 10 microg), 2. 15 mg of OCP combined with 1 microg of rhBMP-2 (OCP/BMP 1 microg), or 3. OCP (OCP alone) was implanted into the defect and fixed at 4 or 8 weeks after implantation. The percentage of newly formed bone (n-Bone%) in the defect was determined by a histomorphometrical analysis. A statistical analysis showed that n-Bone% with OCP/BMP was significantly higher than that with OCP at both time points, whereas the difference in n-Bone% between OCP/BMP 10 microg and OCP/BMP 1 microg was not significant. The present results suggest that OCP can be used as an effective scaffold for rhBMP-2 and this OCP delivery system may be able to reduce the standard effective dose of rhBMP-2, which would be beneficial because low doses (<100 microg/g OCP) of rhBMP-2 enhance bone regeneration.

The activity ratio of the cytosolic MDH/LDH and the isoenzyme pattern of LDH in the peripheral leukocytes of dogs, cats and rabbits

The activities of malate dehydrogenase (MDH) and lactate dehydrogenase (LDH) and the pattern of the isoenzymes of LDH were determined in the peripheral blood leukocytes of dogs, rabbits and cats. Rabbits had significantly higher plasma glucose concentrations than dogs or cats. Feline leukocytes showed higher LDH and lower MDH activities than canine or rabbit leukocytes. The M/L ratio, defined as the MDH activity divided by the LDH activity in cytosolic fractions, was considered to be a good indicator with which to evaluate the metabolic state in animal tissues. The M/L ratio was highest in canine and lowest in feline leukocytes. LDH-2 and LDH-3 isoenzymes were dominant in canine leukocytes. LDH-1 and LDH-2 were dominant in rabbit leukocytes, whereas LDH-5 was dominant in feline leukocytes. It was evident that there were significant differences in energy metabolism between the leukocytes of dogs, rabbits and cats.

Implantation of octacalcium phosphate combined with transforming growth factor-beta1 enhances bone repair as well as resorption of the implant in rat skull defects

In our previous study, we reported that synthetic octacalcium phosphate (OCP) enhances bone repair if implanted in rat skull defects. We hypothesized that OCP can be used as an effective carrier for transforming growth factor-beta1 (TGF-beta1) to promote bone repair. We designed the present study to investigate histomorphometrically whether combination with recombinant human TGF-beta1 could promote bone repair caused by OCP per se (Control/OCP). A full-thickness standardized trephine defect was made in the rat parietal bone and OCP combined with recombinant human TGF-beta1 (TGF-beta1/OCP) or Control/OCP was implanted into the defect. Four rats from each group were fixed at 2, 4, and 8 weeks after implantation. Histomorphometrical analysis of the percentage of newly formed bone (n-Bone %) and remaining implants (r-Imp %) in the defect was performed. The statistical analysis showed the n-Bone % of TGF-beta1/OCP was significantly higher than that of the Control/OCP in week 4, whereas the r-Imp % of TGF-beta1/OCP was significantly lower than that of the Control/OCP. The present study demonstrated that OCP can be used as an effective carrier for TGF-beta1 and their combination enhances bone repair as well as resorption of the carrier OCP in the early stage of bone formation.

CRBP suppresses breast cancer cell survival and anchorage-independent growth

We showed earlier that cellular retinol-binding protein (CRBP) expression is downregulated in a subset of human breast cancers. We have now investigated the outcome of ectopic CRBP expression in MTSV1-7 cells, a SV40 T antigen-transformed human breast epithelial cell line devoid of endogenous CRBP expression. We found that: (i) CRBP did not inhibit adherent cell growth but suppressed foci formation in post-confluent cultures and colony formation in soft agar; (ii) this effect was due to CRBP inhibition of cell survival, as demonstrated by viability and TUNEL assays of cells in soft-agar or plated on polyHEMA-coated dishes; (iii) CRBP inhibited protein kinase B/Akt activation in cells in suspension but not in adherent cells and the CRBP suppression of anchorage-independent growth was mimicked by cell treatment with the phosphatidylinositol-3 kinase (PI3K) inhibitor LY294002; (iv) CRBP enhanced retinyl ester formation and storage but did not regulate retinoic acid synthesis or retinoic acid receptor activity. Ectopic CRBP-mediated inhibition of anchorage-independent cell survival and colony formation in the absence of significantly altered responses to either retinol or retinoic acid was also documented in T47D human breast cancer cells. In conclusion, the data suggest two novel and linked CRBP functions in mammary epithelial cells: inhibition of the PI3K/Akt survival pathway and suppression of anchorage-independent growth.

Expression of beta-synuclein in normal human astrocytes

Although alpha- and beta-synucleins are expressed predominantly in presynaptic nerve terminals, recent studies have demonstrated that alpha-synuclein is also expressed in cultured astrocytes and oligodendrocytes. We determined whether beta-synuclein might be expressed in astrocytes. Beta-synuclein mRNA and protein were detected in normal human astrocytes in culture, and immunofluorescent staining showed that beta-synuclein protein was expressed within the cytoplasm and nucleus. Furthermore, beta-synuclein immunoreactivity was present in astrocytes, but not in oligodendrocytes, in normal human brain tissues. Ultrastructurally, beta-synuclein immunoreactivity was found in the cytoplasm of astrocytes, in association with the plasma membrane, ribosomes, rough endoplasmic reticulum and the nuclear outer membrane. The novel expression of beta-synuclein in astrocytes may provide an important insight about the role of this protein.

Osteoblastic differentiation of periosteum-derived cells is promoted by the physical contact with the bone matrix in vivo

The periosteum contains osteoprogenitors that differentiate to osteoblasts in bone growth or repair. Our previous studies suggested the hypothesis that the physical contact of the periosteum with the bone matrix is requisite for the differentiation of osteoblasts. To test the hypothesis, the present study was designed to investigate how the contact between the periosteum and the bone matrix influences the osteoblastic differentiation of periosteal cells with establishing a new experimental model in vivo. Differentiation of osteoblasts was assessed by gene expression of type I collagen, osteocalcin and bone sialoprotein using in situ hybridization. A barrier was designed to prevent periosteal cells from contacting the bone matrix using the membrane filter. The membrane filter was inserted surgically between the surface of rat parietal bone and the periosteum after being punched out with pin holes. Periosteal cells were allowed to contact with the bone surface only through the pin holes. The pin hole was filled with cells derived from the periosteum 1 week after inserting the filter. Differentiation of osteoblasts in week 2 and noticeable bone formation in week 3 were identified on the bone surface only under the pin hole but not under the filter. The present study demonstrated that the physical contact with the bone matrix promotes osteoblastic differentiation of periosteum-derived cells in vivo.

Apoptosis induced by arsenic trioxide in leukemia U937 cells is dependent on activation of p38, inactivation of ERK and the Ca2+-dependent production of superoxide

The mechanism of the induction of apoptosis by arsenic trioxide (As2O3), which was demonstrated recently to be an effective inducer of apoptosis in patients with leukemia, was examined in detail in human leukemia U937 cells. Upon treatment of U937 cells with 50 microM of As2O3, complete inactivation of the kinases ERK1 and ERK2 was detected within 30 min. p38 was activated within 3 hr, and the maximum activity was detected at 6 hr, when DNA fragmentation remained undetectable. Experiments with transfected cells that expressed constitutively activated MEK1 and a specific inhibitor of p38 also suggested that inactivation of ERKs and activation of p38 might be associated with the induction of apoptosis by As2O3. In contrast to the inactivation of ERKs and the activation of p38, activation of JNK by As2O3 appeared to protect cells against the induction of apoptosis. Treatment of U937 cells with As2O3 also caused the Ca2+-dependent production of superoxide and intracellular acidification and a decrease in the mitochondrial membrane potential at the early stages of induction of apoptosis by As2O3. These changes preceded the release of cytochrome c from mitochondria and the activation of caspase-3. It should be possible to exploit the unusual characteristics of the mechanism of induction of apoptosis by As2O3 in U937 cells by making use of synergistic effects of this compound with other inducers of apoptosis.

Cosecretion of prolactin and growth hormone by dispersed pituitary cells of the adult bullfrog, Rana catesbeiana

The coexistence of prolactin (PRL) and growth hormone (GH) was previously demonstrated in newly hatched bullfrog (Rana catesbeiana) tadpoles, whereas in adult bullfrogs, there were no cells containing both PRL and GH. However, a cell blot assay with enzymatically dispersed adult pituitary cells demonstrated the existence of cells secreting both PRL and GH. The number of cells secreting both PRL and GH was reduced by a protein synthesis inhibitor, cycloheximide, but not by an RNA synthesis inhibitor, actinomycin D. In situ hybridization and immunostaining of intact pituitary glands revealed the existence of GH mRNA in some of the PRL-immunoreactive cells and of PRL mRNA in some of the GH-immunoreactive cells. We propose that dispersion of the pituitary cells triggered the translation of GH mRNA in the PRL cells and/or of PRL mRNA in the GH cells.

Postmortem absorption of dichloromethane: a case study and animal experiments

A case of accidental death after occupational exposure to an atmosphere containing dichloromethane (DCM) is reported. The concentrations of DCM in the blood and tissues of a 40-year-old man who died while observing an industrial washing machine filled with DCM vapour were blood 1660 mg/l, urine 247 mg/l, brain 87 mg/kg, heart muscle 199 mg/kg and lungs 103 mg/kg which are 3-7 times higher than previously reported fatal levels. The body was left undiscovered in the machine filled with DCM vapour for about 20 h. The present study was designed to determine whether all the DCM detected in the tissues and body fluids had been inhaled while alive using rats as the experimental model. The concentrations of DCM in the tissues and body fluids of a rat that died from DCM poisoning and was left for 20 h in a box containing DCM vapour were the same as those in the tissues and body fluids of a rat that had died from an injected overdose of barbiturates and had then been placed in the DCM box in a similar manner. Moreover, the concentrations of DCM in the tissues and body fluids of the carcasses that were exposed to the DCM vapour increased gradually throughout the period of exposure. These findings imply that DCM is able to penetrate the tissues and body fluids of rat carcasses through a route other than inhalation such as through the skin.

Functional significance of colocalization of PACAP and catecholamine in nerve terminals

Medullary neurons containing pituitary adenylate cyclase-activating polypeptide (PACAP) and noradrenalin (NA) project to the hypothalamus and they are involved in the regulation of arginine vasopressin (AVP) neurons. At the ultrastructural level, PACAP immunoreactivity was detected in the granular vesicles in catecholaminergic nerve terminals that made synaptic contact with AVP neurons. Both PACAP (at least 1 nM) and NA (at least 1 microM) induced large increases in the cytosolic Ca2+ concentration ([Ca2+]i) in isolated AVP cells. PACAP at 0.1 nM and NA at 0.1 microM had little effects, if any, on [Ca2+]i. However, when 0.1 nM PACAP and 0.1 microM NA were combined, they evoked large increase in [Ca2+]i in AVP neurons. An inhibitor of protein kinase A (PKA) completely inhibited the PACAP-induced increase in [Ca2+]i, but only partly inhibited the NA-induced increase in [Ca2+]i. In AVP cells that were prelabeled with quinacrine, PACAP and NA acted synergistically to induce a loss of quinacrine fluorescence, indicating secretion of neurosecretory granules in AVP neurons. The results suggest that PACAP and NA, coreleased from the same nerve terminals, act in synergy to evoke calcium signaling and secretion in AVP neurons, and that the synergism is mediated by the interaction between cAMP-PKA pathway an as yet unidentified factor "X" linked to L-type Ca2+ channels. The synergism between PACAP and NA may contribute to the regulation of AVP secretion under physiological conditions.

Atp-binding cassette transporter ABC2/ABCA2 in the rat brain: a novel mammalian lysosome-associated membrane protein and a specific marker for oligodendrocytes but not for myelin sheaths

We recently cloned a full-length cDNA of the rat ATP-binding cassette transporter 2 (ABC2, or ABCA2) protein, a member of the ABC1 (or ABCA) subfamily (-ABC1/ABCA1 is a causal gene for Tangier disease) and found it to be strongly expressed in the rat brain. In this study, we identified ABC2 as a lysosome-associated membrane protein that is being localized specifically in oligodendrocytes. The ABC2-immunolabeled cells were detected mainly in the white matter but were also scattered in gray matter throughout the whole brain. In addition, these cells were found to be colocalized with 2',3'-cyclic nucleotide-3'-phosphodiesterase (CNPase) immunoreactivity when the marker antibody for oligodendrocytes was used. However, no such colocalization was observed with markers for other kinds of glial cells. Unlike the CNP antibody, which also intensely stains myelin sheaths in the white matter, ABC2 immunoreactivity was detected only in the cell bodies of oligodendrocytes. At the ultrastructural level, ABC2 immunoreactivity was detected mostly around lysosome and partly in Golgi apparatus by electron microscopy. This was confirmed by immunocolocalization of ABC2 and lysosomal markers in a neuroblastoma cell line. Immunoblotting analysis of ABC2 from the whole brain and the ABC2-transfected cell line revealed bands at approximately 260 kDa. The result of in situ hybridization with a riboprobe for ABC2 matched the results obtained from immunostaining. These findings strongly suggest that ABC2 is a specific marker for oligodendrocytes but not for myelinsheaths and that it is as a novel mammalian lysosome-associated membrane protein involved in myelinization or other kinds of metabolism in the CNS.

Induction of drug metabolism-related enzymes by methylcholanthrene and phenobarbital in transgenic mice carrying human prototype c-Ha-ras gene and their wild type littermates

Transgenic mice hemizygously carrying human c-Ha-ras proto-oncogene, Tg-rasH2 show very sensitive and facilitated carcinogenicity to various carcinogens. In this study, activities of certain enzymes related to drug metabolism and energy metabolism were measured in microsome and cytosol fractions of livers of Tg-rasH2 mice and their wild type littermates with both sexes treated with 3-methylcholanthrene (MC) and phenobarbital (PB). Aminopyrine N-demethylase activities increased significantly in livers of all mice treated with PB. MC and PB treatments induced significant increases in activities of UDP-glucuronosyltransferase and S-adenosyl homocysteinase compared to those in the non-treated groups in microsome fractions from all mice. In cytosol fractions of livers of all mice, glutathione S-transferase activity was significantly induced in the PB treated groups. There were no significant differences in activities of lactate dehydrogenase, glucose 6-phosphate dehydrogenase, pyruvate kinase and glucose 6-phosphatase related to energy metabolism in livers and kidneys among all mice. Tg-rasH2 mice showed stable activities of enzymes related to drug detoxication and energy metabolism similar to those of non-transgenic mice. These results suggest that the human c-Ha-ras transgene may not affect drug metabolism-related enzymes, and the facilitated carcinogenic response in the Tg-rasH2 mouse is not due to these enzymatic disorders.

Effect of prolactin and androgen on the expression of the female-attracting pheromone silefrin in the abdominal gland of the newt, Cynops ensicauda

Silefrin is a sodefrin-like, female-attracting pheromone comprising 10 amino acids that was isolated from the abdominal gland of the sword-tailed newt, Cynops ensicauda. Hormonal effects on the silefrin precursor mRNA expression and silefrin content in the abdominal gland were investigated in the present study by using Northern blot analysis and radioimmunoassay, respectively. In the abdominal gland of newts treated with prolactin (PRL) plus testosterone propionate (TP), silefrin precursor mRNA expression was markedly enhanced as compared with that in the newts injected with saline, PRL, or TP. Values for radioimmunoassayable silefrin content in the abdominal gland paralleled those for the silefrin precursor mRNA levels. Moreover, silefrin precursor mRNA signals, as revealed by in situ hybridization, as well as stainability of immunoreactive silefrin were much more intense in the epithelial cells of the abdominal gland of the PRL-plus-TP-treated animals than in those of controls. We thus conclude that PRL and androgen are important factors for enhancing silefrin synthesis.

The mechanism of geranylgeraniol-induced apoptosis involves activation, by a caspase-3-like protease, of a c-jun N-terminal kinase signaling cascade and differs from mechanisms of apoptosis induced by conventional chemotherapeutic drugs

In the present study, we investigated the effects of geranylgeraniol (GGO), a potent inducer of apoptosis in various lines of human tumor cells, on signal transduction cascades involved in apoptosis in human leukemia cells. GGO strongly induced the activation of c-Jun N-terminal kinase (JNK/SAPK) within 2 h in U937 and K562 cells, while neither ERK nor p38 was activated to any considerable extent during GGO-induced apoptosis. Transient expression of a constitutively active mutant form of mitogen-activated protein kinase kinase 1 (MEKK1), deltaMEKK1, or of deltaMEKK1-green fluorescent protein (GFP) in K562 cells activated JNK, but not a caspase-3-like protease, and was insufficient to induce cell death but rendered cells susceptible to GGO-induced cell death. Stable expressions of deltaMEKK1-GFP in U937 cells gave similar results. In contrast to VP-16-induced apoptosis, GGO-induced activation of JNK was almost completely inhibited by benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethylketone (Z-DEVD) and by benzyloxycarbonyl-Asp-CH2OC[O]-2,6,-dichlorobenzene (Z-Asp), indicating that the JNK-activation step is located downstream of the caspase signaling pathway in GGO-induced apoptosis. Moreover, apoptosis induced by GGO was significantly inhibited in two lines of cells with a dominant-negative deletion mutation in c-Jun, indicating a requirement for JNK signaling. In addition, unlike the effects on other inducers of apoptosis, the activation of JNK and of the caspase-3-like protease by GGO was significantly delayed by 12-O-tetradecanoylphorbol-13-acetate (TPA), suggesting that the site of inhibition by TPA might be located upstream of the protease and JNK in the GGO-induced apoptotic signaling pathway.

Splice variants of PAC(1) receptor during early neural development of rats

The specific pituitary adenylate cyclase-activating polypeptide (PACAP) receptor, PAC(1)-R, consists of at least seven isoforms, and they are differentially coupled to signal transduction pathways by alternative splicing. We have found that the major splice variants of the PAC(1) receptor seen during development are the short splice isoform, PAC(1)-R-s (which does not contain either the "hip" or "hop" cassette), and another form, PAC(1)-R-hop (which contains the "hop" cassette). We also have applied an innovative molecular histochemical technique, in situ reverse transcription-polymerase chain reaction (RT-PCR), and determined that these two splice isoforms are colocalized in the neuroepithelia from the primitive streak stage.

Stromal cell-independent differentiation of human cord blood CD34+CD38- lymphohematopoietic progenitors toward B cell lineage

To study the cytokine regulation of early stages of human B-lymphopoiesis, we developed a stroma-free two-step culture system. Single human cord blood CD34+CD38- cells were individually cultured by micromanipulation with interleukin (IL)-3, stem cell factor (SCF), fIt3 ligand (FL), IL-6 and granulocyte colony-stimulating factor (G-CSF). About 10% of the cells formed primary colonies, which were individually tested for myeloid and B-lymphoid potentials by reculturing aliquots of the primary colony cells into secondary myeloid and B-lymphoid cultures. One third of the primary colonies proved capable of differentiation into CD19+IgM+ cells, as well as into myeloid lineage cells. RT-PCR analyses revealed that some cells in the primary culture had already matured to express B cell-specific transcripts. Thus, the combination of IL-3, SCF, FL, IL-6 and G-CSF supported the differentiation of CD34+CD38- lymphohematopoietic progenitors toward B cell lineage in addition to myeloid lineages. Screening of cytokines to identify the minimum requirement of cytokines in the primary culture revealed that IL-3 and SCF were essential and that the addition of FL, and to a lesser extent IL-6 or G-CSF, to the combination of IL3 and SCF remarkably enhanced the primary colony formation and the generation of CD19+ cells in the secondary B-lymphoid culture.

Serum total bile acid level as a sensitive indicator of hepatic histological improvement in chronic hepatitis C patients responding to interferon treatment

BACKGROUND AND METHODS

Serum total bile acid (TBA) levels are used clinically as a sensitive and reliable index of hepatobiliary diseases. In the present study, to assess the clinical usefulness of determining TBA in interferon (IFN)-treated patients, changes in liver function test values, including TBA and liver histology, were examined in 36 chronic hepatitis C patients for 3 years after a sustained response to IFN treatment.

RESULTS

Alanine aminotransferase and gamma-glutamyl transpeptidase values significantly decreased during the period of IFN treatment compared to the same measures before IFN treatment. Albumin, cholinesterase, total cholesterol and platelet count values temporarily decreased during IFN treatment, then increased significantly and reached a plateau 6-12 months after the end of IFN treatment. The zinc sulphate turbidity test and TBA values began to decrease during IFN treatment and continued to decrease during the 3-year follow-up period. The histological activity index of the liver (Knodell's score) significantly decreased, whereas the staging score was unchanged 1 year after the end of IFN treatment. In patients who had a TBA value > 10 micromol/L before IFN treatment, a significant correlation was observed between the decrease of TBA and liver histology grading score.

CONCLUSIONS

A decrease in serum TBA level reflected histological improvement in the liver more precisely than did changes in the other liver function test values following IFN therapy.

Cellular distribution of the splice variants of the receptor for pituitary adenylate cyclase-activating polypeptide (PAC(1)-R) in the rat brain by in situ RT-PCR

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a pleiotropic neuropeptide and its specific receptor (the PAC(1) receptor) is widely distributed in the rat brain. It has been reported that alternative splicing of the region encoding the third intracellular loop of the PAC(1) receptor generates six isoforms which are differentially coupled to signal transduction pathways, but the precise distribution and localization of these splice isoforms in the brain remain to be determined. Using the initial specific primer pairs which correspond to the 'hip' or 'hop' types of receptors for the solution-phase reverse transcription-polymerase chain reaction (RT-PCR), we demonstrated that the major splice variants of the PAC(1) receptor in various regions of the rat brain are the short splice isoform 'PAC(1)-R-s' which does not contain either the 'hip' or 'hop' cassette and the another splice isoform, 'PAC(1)-R-hop', which contains the 'hop' cassette. With an innovative molecular histochemical technique, in situ RT-PCR, we determined that these two splice isoforms are both intensely expressed in the mitral cells of the olfactory bulb, the Purkinje cells of the cerebellum, the pyramidal cells of the hippocampus and neocortex, and many neurons in the nuclei of hypothalamus and thalamus as well as other regions. The initial mapping of the cell type-specific expression of these two splice variants of the PAC(1) receptor provides the basis for a better understanding of the functional significance of the PAC(1)-R and its ligand PACAP in various brain regions.

Constitutive phosphorylation of the Parkinson's disease associated alpha-synuclein

alpha-Synuclein has been implicated in the pathogenesis of Parkinson's disease, since rare autosomal dominant mutations are associated with early onset of the disease and alpha-synuclein was found to be a major constituent of Lewy bodies. We have analyzed alpha-synuclein expression in transfected cell lines. In pulse-chase experiments alpha-synuclein appeared to be stable over long periods (t((1)/(2)) 54 h) and no endoproteolytic processing was observed. alpha-Synuclein was constitutively phosphorylated in human kidney 293 cells as well as in rat pheochromocytoma PC12 cells. In both cell lines phosphorylation was highly sensitive to phosphatases, since okadaic acid markedly stabilized phosphate incorporation. Phosphoamino acid analysis revealed that phosphorylation occurred predominantly on serine. Using site-directed mutagenesis we have identified a major phosphorylation site at serine 129 within the C-terminal domain of alpha-synuclein. An additional site, which was phosphorylated less efficiently, was mapped to serine 87. The major phosphorylation site was located within a consensus recognition sequence of casein kinase 1 (CK-1). In vitro experiments and two-dimensional phosphopeptide mapping provided further evidence that serine 129 was phosphorylated by CK-1 and CK-2. Moreover, phosphorylation of serine 129 was reduced in vivo upon inhibition of CK-1 or CK-2. These data demonstrate that alpha-synuclein is constitutively phosphorylated within its C terminus and may indicate that the function of alpha-synuclein is regulated by phosphorylation/dephosphorylation.

Analysis of caspases that are activated during apoptosis in leukemia U937 cells in response to geranylgeraniol

Affinity labeling showed that active caspases with molecular masses of 20 kDa, 19 kDa, and 17 kDa were formed upon treatment of human leukemia U937 cells with GGO. These caspases are quite similar to those activated by treatments with other apoptosis-inducers, such as VP16 and camptothecin, suggesting that similar caspases, such as caspases 3 and 6, are activated during apoptosis in U937 cells that is induced by a variety of apoptosis-inducing stimuli. An inhibitor of caspases, Z-Asp-CH2DCB, inhibited DNA fragmentation in response to GGO in vivo by blocking the cleavage of 20-kDa to 17-kDa peptides. This cleavage is catalyzed by caspase 3 itself or by a caspase-3-like protease. In contrast, other inhibitors of caspases such as Z-DEVD-FMK and Z-VAD-FMK, inhibited the processing of the caspase 3 precursor p32 to 20-kDa and 17-kDa peptides, a result which suggests that these inhibitors inhibited other upstream caspases. Treatment of U937 cells with GGO resulted in the release of cytochrome c from mitochondria prior to DNA fragmentation and the release of cytochrome c was inhibited by Zn2+ ions and by a chelator of Ca2+ ions but not by inhibitors of caspases such as Z-Asp-CH2DCB or Z-VAD-FMK. These results suggest that intracellular free Ca2+ ions, and some caspases that are inhibited by Zn2+ ions, but not by Z-Asp-CH2DCB or Z-VAD-FMK are necessary for the release of cytochrome c that is caused by the treatment with GGO.

Pituitary adenylate cyclase-activating polypeptide receptors during development: expression in the rat embryo at primitive streak stage

The distribution and localization of the pituitary adenylate cyclase-activating polypeptide (PACAP) receptor the PAC1 receptor (previously called the type 1 PACAP receptor or PVR1), which binds PACAP, but not vasoactive intestinal peptide, with high affinity] were first investigated in rats with in situ hybridization for its messenger RNA, and with immunohistochemical methods during prenatal and postnatal development. The expression of PACAP receptor messenger RNA was first detected in the rat embryo at the primitive streak stage as early as embryonic day 9, and it was intensely expressed in the neural plate. PACAP receptor messenger RNA was also intensely expressed in the neuroepithelia of the mesencephalon and rhombencephalon at embryonic day 11, and expressed in the basal telencephalon, hippocampal formation neuroepithelium, cortical neuroepithelium and cerebellar neuroepithelium after embryonic day 13. It was also expressed in the olfactory bulb neuroepithelium after embryonic day 16, and in mature regions of the older embryos. In postnatal developing brains, PACAP receptor messenger RNA was intensely expressed in the olfactory bulb, hippocampal formation, cerebellum and other scattered regions. The localization of PACAP receptor-like immunoreactivity coincided well with that of the gene transcripts. We also used reverse transcription-polymerase chain reaction methods to determine the expression of the splice variants of the PACAP receptor gene. At each ontogenetic stage of the rat from embryonic day 9 to postnatal day 60, two major products were detected with reverse transcription-polymerase chain reaction, a thick band (303 base pairs) corresponding to the short splice variant of the receptor that lacks both the "hip" and "hop" cassettes, and a thin band (387 base pairs) corresponding to the splice variant that contains one cassette of "hop" or "hip". There was no evidence for the other larger splice variants. Some of the amplified products were sequenced and found to have the exact sequences of "PACAP receptor" and "PACAP receptor-hopl", which are coupled to different signal transduction pathways. These results indicate that the PACAP receptor is actively expressed in different neuroepithelia from early developmental stages and expressed in various brain regions during prenatal and postnatal development, and that the major splice variants are "PACAP receptor" and "PACAP receptor-hopl". The initial mapping of ontogenetic localization of the PACAP receptor provides the basis for a better understanding of the functions of PACAP and its receptors during the development of the brain.

Induction of apoptosis by bufalin in human tumor cells is associated with a change of intracellular concentration of Na+ ions

In an attempt to characterize the mechanisms that are operative at the early stages of the induction of apoptosis by bufalin, a component of the traditional Chinese medicine chan'su, we examined the effects of bufalin on plasma membrane potential, as determined by monitoring the uptake by cells of rhodamine 123. Bufalin induced apoptosis in human monocytic leukemia THP-1 cells, in human lymphoblastic leukemia MOLT-3 cells, and in human colon adenocarcinoma COLO320DM cells but not in normal human leukocytes, for example, polymorphonuclear cells and lymphocytes, and not in murine leukemia P388D1 and M1 cells. Treatment for 3 h with bufalin at 10(-6) M caused a decrease in the plasma membrane potential in several lines of human tumor cells but not in murine leukemia cells. No changes in mitochondrial membrane potential, as monitored with the fluorescent dye JC-1, and no release of cytochrome c were observed within at least 6 h after the start of treatment with bufalin. Moreover, overexpression of bcl-2 in human leukemia HL60 cells that had been transfected with cDNA for bcl-2 prevented bufalin-induced apoptosis but had no significant effect on the change in plasma membrane potential induced by bufalin. Since bufalin specifically inhibits the Na+,K(+)-ATPase of human but not murine tumor cells, and since this inhibition leads to a change in intracellular concentration of Na+ ions, our findings suggest that bufalin induces apoptosis in human tumor cells selectively via inhibition of the Na+,K(+)-ATPase, which acts upstream of the bcl-2 protein.

Tiam1 is involved in the regulation of bufalin-induced apoptosis in human leukemia cells

Bufalin, a component of the Chinese medicine chan'su, induces apoptosis in various lines of human tumor cells, such as leukemia HL60 and U937 cells, by altering the expression of apoptosis-related genes, for example, bcl-2 and c-myc. In this study, we characterized a gene that is involved in bufalin-induced apoptosis by the differential display (DD) technique. The partial nucleotide sequence of one of the differentially expressed clones obtained after treatment with bufalin was identical to that of the human gene for Tiam1. When U937 cells were treated with 10(-7) M bufalin, expression of both Tiam1 mRNA and the protein was induced 1 h after the start of the treatment. The increase of Tiam1 mRNA was transient but the level of Tiam1 protein continued to increase at least for 6 h. In addition, the activities of Rac1 and p21-activated kinase (PAK) were also stimulated by bufalin treatment. To evaluate the role of Tiam1 in the apoptotic process, we examined the effects of the expression of sense and antisense RNA for Tiam1 in U937 cells. Apoptosis was strongly induced by bufalin in cells that expressed sense RNA for Tiam1 as compared to apoptosis in control cells treated with bufalin only. Cells expressing antisense RNA for Tiaml were significantly more resistant than the control bufalin-treated cells to induction of DNA fragmentation in response to bufalin. Moreover, sense transformants had elevated activities of PAK and c-Jun NH2-terminal kinase (JNK). These results suggest that Tiaml might play a critical role in bufalin-induced apoptosis through the activation of Rac1, PAK, and JNK pathway.

Delayed neuronal cell death in the rat hippocampus is mediated by the mitogen-activated protein kinase signal transduction pathway

Transient global ischemia caused by 5 min of cardiac arrest induced delayed neuronal cell death (apoptosis) in the CA1 region of the rat hippocampus. To characterize the molecular mechanisms that regulate apoptosis in vivo, the contributions to cell death of mitogen-activated protein kinase family members were examined in the hippocampal region after brain ischemia-reperfusion. Ischemia-reperfusion led to a strong activation of the JNK/SAPK (c-Jun NH2-terminal protein kinase/stress activated protein kinase), ERK (extracellular signal-regulated kinase), and p38 enzymes. These results with other previous studies suggest that the activation of JNK/SAPK in accordance with p38 contributes to the induction of apoptosis in CA1 neurons.

beta-hydroxyisovalerylshikonin inhibits the cell growth of various cancer cell lines and induces apoptosis in leukemia HL-60 cells through a mechanism different from those of Fas and etoposide

beta-Hydroxyisovalerylshikonin (beta-HIVS), which was isolated from the plant, Lithospermium radix, inhibited the growth of various lines of cancer cells derived from human solid tumors at low concentrations between 10(-8) and 10(-6) M. When HL-60 cells were treated with 10(-6) M beta-HIVS for 3 h, characteristic features of apoptosis, such as DNA fragmentation, nuclear fragmentation, and activation of caspase-3-like activity, were observed. The most characteristic features of the effect of beta-HIVS were the remarkable morphological changes induced upon treatment of HL-60 cells with beta-HIVS, as visualized on the staining of actin filaments with phalloidin labeled with tetramethylrhodamine B isothiocyanate. Moreover, activation of MAP kinases, such as ERK2, JNK and p38, was detected after treatment with 10(-6) M beta-HIVS preceding the appearance of the characteristics of apoptosis, and the features of the activation of these MAP kinases were quite different from those of Fas and anticancer drug-induced apoptosis. The activation of JNK by beta-HIVS was not inhibited by inhibitors of caspases, suggesting that JNK is located either upstream or independent of the caspase signaling pathway. beta-HIVS did not inhibit the activity of topoisomerase II. These results indicate that beta-HIVS induces apoptosis in HL-60 cells through a mechanism unlike those reported for anti-Fas antibodies and etoposide.

Boswellic acid acetate induces differentiation and apoptosis in leukemia cell lines

Boswellic acid acetate (BC-4), a compound isolated from the herb Boswellia carterii Birdw., can induce differentiation and apoptosis of leukemia cells. Based on cell morphology and NBT reduction, BC-4 induced monocytic differentiation of myeloid leukemia HL-60, U937 and ML-1 cells at a dose under 12.5 microg/ml (24.2 microM). BC-4 was a potent inducer, with 90% of the cells showing morphologic changes and 80-90% of the cells showing NBT reduction. Specific and non-specific esterase were also increased by BC-4. Based on benzidine staining assay, BC-4 failed to induce erythroid leukemia DS-19 and K562 cells differentiation. In contrast to its selective differentiation effect, BC-4 strongly inhibited growth of all cell lines tested. The growth inhibition effect was dose- and time-dependent. In HL-60 cells, 20 microg/ml (38.8 microM) of BC-4 decreased viable cell number by 60% at 24 h, whereas at 3 days there was virtually no viable cells. Morphologic and DNA fragmentation analysis proved that BC-4 induced cell apoptosis. The dual apoptotic and differentiation effects of BC-4 suggest that it may be a powerful agent in the treatment of leukemia.

PACAP protects hippocampal neurons against apoptosis: involvement of JNK/SAPK signaling pathway

We have demonstrated that the ischemia-induced apoptosis of neurons in the CA1 region of the rat hippocampus was prevented by either intracerebroventricular or intravenous infusion of pituitary adenylate cyclase-activating polypeptide (PACAP). However, the molecular mechanisms underlying the anti-apoptotic effect of PACAP remain to be determined. Within 3-6 h after ischemia, the activities of members of the mitogen-activated protein (MAP) kinase family, including extracellular signal-regulated kinase (ERK), Jun N-terminal kinase (JNK)/stress-activated protein kinase (SAPK), and p38 were increased in the hippocampus. The ischemic stress had a potent influence on the MAP kinase family, especially on JNK/SAPK. PACAP inhibited the activation of JNK/SAPK after ischemic stress. Secretion of interleukin-6 (IL-6) into the cerebrospinal fluid was intensely stimulated after PACAP infusion. IL-6 inhibited the activation of JNK/SAPK, while it activated ERK. These observations suggest that PACAP and IL-6 act to inhibit the JNK/SAPK signaling pathway, thereby protecting neurons against apoptosis.

Expression of the nicotinic acetylcholine receptor alpha4 subunit mRNA in the rat cerebellar cortex

In order to compare the previous immunohistochemical and immunocytochemical data on the distribution of nicotinic acetylcholine receptor alpha4 subunit-like immunoreactivity with the expression of alpha4 mRNA in the rat cerebellar cortex, the present study determined the cellular distribution of alpha4 mRNA in the rat cerebellar cortex. Northern blot analysis revealed two alpha4 mRNA bands in the rat cerebellum and three in the cerebral cortex, hippocampus, hypothalamus and striatum. The total level of these transcripts was lower in the cerebellum than in the other four regions. The expression of alpha4 mRNA was high in Purkinje cells and granular cells, whereas low expression was detected in the molecular layer. These results suggest that the expression of alpha4 mRNA is closely related to the alpha4-like immunoreactivity in the molecular and Purkinje cell layers. In the granular layer, alpha4 mRNA was very highly and broadly expressed in comparison with the alpha4-like immunoreactivity.

The expression of heme oxygenase-1 gene responded to oxidative stress produced by phorone, a glutathione depletor, in the rat liver; the relevance to activation of c-jun n-terminal kinase

Phorone, a glutathione (GSH) depletor, induces the expression of mRNAs of heme oxygenase-1 (HO-1) and c-jun by mediating the activation of activated protein-1 (AP-1) in rat livers. We have shown that phorone activates c-Jun N-terminal kinase (JNK), thus leading to c-Jun phosphorylation, and transactivation of AP-1 and HO-1 gene expression in the rat liver in response to oxidative stress. The in-gel kinase assay showed that phorone activated JNK1 predominantly in the rat liver nuclear extract. The JNK activation by phorone was slightly observed at 1 hr after administration and gradually increased with time. Ser73-phosphorylation of c-Jun catalyzed by JNK was significantly altered by changing hepatic GSH levels based on the results observed by the combined injection of buthionine sulfoximine (BSO) or GSH isopropyl ester (GIP) with phorone. Namely, BSO, an inhibitor of GSH biosynthesis, enhanced phorone-mediated c-Jun phosphorylation as well as AP-1 binding activity. However, GSH isopropyl ester prevented GSH depletion and abolished both c-Jun phosphorylation and the activation of AP-1 binding evoked by phorone. GSH isopropyl ester also suppressed phorone-produced HO-1 and c-jun gene expressions to 25 and 30% of the induced level. Perfluorodecanoic acid (PFDA) reduced GSH S-transferase activity, prevented phorone-mediated GSH depletion and abolished either HO-1 or c-jun mRNA induction by phorone. These results indicated that oxidative stress under GSH depletion produced by phorone could activate preferentially JNK and lead to the transcriptional activation of AP-1 and consequently to HO-1 gene expression. This study suggests that JNK activation could be one of the major signaling pathways to transmit intracellular events to the nuclei during oxidative stress via GSH depletion by phorone in rat livers.

Glial cytoplasmic inclusions in white matter oligodendrocytes of multiple system atrophy brains contain insoluble alpha-synuclein

Recently, alpha-synuclein was shown to be a structural component of the filaments in Lewy bodies (LBs) of Parkinson's disease (PD), dementia with LBs (DLB) as well as the LB variant of Alzheimer's disease, and this suggests that alpha-synuclein could play a mechanistic role in the pathogenesis of these disorders. To determine whether alpha-synuclein is a building block of inclusions in other neurodegenerative movement disorders, we examined brains from patients with multiple system atrophy (MSA) and detected alpha-synuclein, but not beta- or gamma-synuclein, in glial cytoplasmic inclusions (GCIs) throughout the MSA brain. In MSA white matter, alpha-synuclein-positive GCIs were restricted to oligodendrocytes, and alpha-synuclein was localized to the filaments in GCIs by immunoelectron microscopy. Finally, we demonstrated that insoluble alpha-synuclein accumulated selectively in MSA white matter with alpha-synuclein-positive GCIs. Taken together with evidence that LBs contain insoluble alpha-synuclein, our data suggest that a reduction in the solubility of alpha-synuclein may induce this protein to form filaments that aggregate into cytoplasmic inclusions, which contribute to the dysfunction or death of glial cells as well as neurons in neurodegenerative disorders with different phenotypes.

Zinc ions prevent processing of caspase-3 during apoptosis induced by geranylgeraniol in HL-60 cells

Geranylgeraniol (GGO) at 50 microM induces apoptosis in HL-60 cells. We examined the effects of Zn2+ ions on this process. Treatment of HL-60 cells with Zn2+ ions inhibited subsequent GGO-induced fragmentation of DNA. In a cell-free system that consisted of a specific substrate for caspase-3 and a lysate of HL-60 cells that had been treated with 50 microM GGO, Zn2+ ions at concentrations above 0.1 mM inhibited the activity of caspase-3. The effect of Zn2+ ions on the processing of caspase-3 during GGO-induced apoptosis was investigated by Western blotting, which revealed that an inactive 32-kDa precursor of caspase-3 was cleaved, in response to GGO, to yield an activated 17-kDa enzyme. Treatment of HL-60 cells with Zn2+ ions inhibited the cleavage of the precursor by a protease that was induced by treatment with GGO, and inhibition of this processing was well correlated with the inhibition by Zn2+ ions of caspase-3 activity in the cell-free system. In cell-extracted cytosols, Zn2+ ions inhibited the cleavage of the 32-kDa precursor by caspase-9 (Aapf-3) that was activated by addition of cytochrome c and dATP. These results indicate that inhibition of GGO-induced apoptosis in HL-60 cells by Zn2+ ions might be due to inhibition by Zn2+ ions of the processing of a precursor to caspase-3.

Distribution of PNP 14 (beta-synuclein) in neuroendocrine tissues: localization in Sertoli cells

Phosphoneuroprotein (PNP 14) is abundant in the central nervous system and is localized at nerve endings but not in synaptic vesicles. In this study, we examined the presence of PNP 14 in various endocrine tissues of the rat. PNP 14 was not detected in the endocrine cells of the intestine, testes, or adrenal gland, but it was present in axon terminals in both the medulla of the adrenal gland and the anterior pituitary gland. When testes were stained with PNP 14-specific antibodies by an indirect immunofluorescence method, PNP 14 was found in Sertoli cells of the testes, associated with fibrillar structures. PNP 14 was also detected in cultured Sertoli cells with a fibrillar pattern in the cytoplasm and around the nuclei. The fibrillar structure did not resemble actin stress fibers, microtubules, or intermediate filaments. The amount of PNP 14 in the testis changed with development. It increased markedly during the first 4 weeks after birth and then decreased. During the first 4 weeks after birth, spermatogonia undergo two rounds of meiosis. It is possible, therefore, that PNP 14 might be a factor related to meiosis.

Quality control of white cell-reduced red cells: white cell preservation and simplified counting

BACKGROUND

White cell (WBC) degradation restricts the interval between the filtration process and the assay for residual WBCs. Maintaining WBC integrity would permit extended sample storage for batching and/or shipment to centralized laboratories. The usual quality control assay for WBC-reduced red cell units requires determining the number of WBCs in the entire counting area of a Nageotte hemocytometer, which consists of 40 rows. Reducing the counting area would simplify the quality control procedure.

STUDY DESIGN AND METHODS

Adsol red cell units were prepared either on the day of collection (Day 0) or on Day 1 and WBC reduced by filtration on the same day. By using prefiltration and postfiltration red cells, samples containing WBC concentrations of 15, 10, and 3 WBCs per microL were prepared by serial dilution. Identical samples were treated with glutaraldehyde and stored at either 20 to 24 degrees C or 1 to 6 degrees C. All samples were assayed on the day of component preparation and on Days 7 and 14. The numbers of WBCs corresponding to 10- and 40-row areas of the Nageotte hemocytometer were determined.

RESULTS

For the conditions and WBC concentration range studied, no significant changes in WBC concentrations were observed through Day 14 for glutaraldehyde-treated samples stored at either temperature, although there were substantial decreases in untreated samples. A 10-row measurement was determined to be sufficient for identifying WBC-reduced red cell units passing the present limit of 5 x 10(6) residual WBCs.

CONCLUSION

Glutaraldehyde treatment can preserve WBCs in red cell samples at least up to Day 14, which provides increased efficiency in quality control for laboratories. Current red cell WBC-reduction filters produce components that, when assayed, contain fewer than 10 WBCs per full counting area. The simplified procedure would allow reduction of the counting area by 75 percent.

Aggregation of alpha-synuclein in Lewy bodies of sporadic Parkinson's disease and dementia with Lewy bodies

Lewy bodies (LBs) are hallmark lesions of degenerating neurons in the brains of patients with Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Recently, a point mutation in the gene encoding the presynaptic alpha-synuclein protein was identified in some autosomal-dominantly inherited familial PD pedigrees, and light microscopic studies demonstrated alpha-synuclein immunoreactivity in LBs of sporadic PD and DLB. To characterize alpha-synuclein in LBs, we raised monoclonal antibodies (MAbs) to LBs purified from DLB brains and obtained a MAb specific for alpha-synuclein that intensely labeled LBs. Light and electron microscopic immunocytochemical studies performed with this MAb as well as other antibodies to alpha-and beta-synuclein showed that alpha-synuclein, but not beta-synuclein, is a component of LBs in sporadic PD and DLB. Western blot analyses of highly purified LBs from DLB brains showed that full-length as well as partially truncated and insoluble aggregates of alpha-synuclein are deposited in LBs. Thus, these data strongly implicate alpha-synuclein in the formation of LBs and the selective degeneration of neurons in sporadic PD and DLB.

Vasopressin neuron activation and Fos expression by stimulation of the caudal ventrolateral medulla

The present study demonstrates that projections ascending from the caudal ventrolateral medulla have direct effects on the expression of the immediate early gene c-fos and of the arginine-vasopressin gene in neurosecretory cells of the hypothalamic supraoptic nucleus. Intense Fos-like immunoreactivity (Fos-LI) was observed in many magnocellular neurons of the supraoptic nucleus after electrical stimulation of the caudal ventrolateral medulla. In sham-operated rats, Fos-LI was absent or present in very few magnocellular neurons in the supraoptic nucleus. Fos-LI was visible in neurons expressing arginine-vasopressin, and was seen rarely in oxytocin neurons by double-immunostaining method. This study showed that 76% of all Fos-positive cells were arginine-vasopressin immunoreactive, whereas only 4% of them showed oxytocin immunoreactivity in the supraoptic nucleus. With in situ hybridization, a high level of arginine-vasopressin mRNA was noted in the supraoptic nucleus 3 h after stimulation of the caudal ventrolateral medulla; the expression was highest 6 h after the stimulation compared with the same region in sham-operated animals. These findings suggest that noradrenaline, released from the axon terminals originating from the caudal ventrolateral medulla, may participate in the regulation of gene transcription of arginine-vasopressin in response to physiological stimuli.

Immunohistochemical localization of leptin receptor in the rat brain

The distribution of leptin receptor in the rat brain was determined by immunocytochemistry and Western blotting. Strong leptin receptor immunoreactivity was detected in the arcuate, paraventricular and ventromedial nuclei of the hypothalamus, and lateral hypothalamic area. The olfactory bulb, neocortex, cerebellar cortex, dorsal raphe nucleus, inferior olive nucleus, nucleus of the solitary tract, dorsal motor nucleus of the vagus nerve also showed intense immunoreactivity. Western blotting analysis yielded a 120-kDa major band.

Activation of AP-1 is required for bufalin-induced apoptosis in human leukemia U937 cells

In a previous study, we demonstrated that bufalin caused apoptosis in human leukemia U937 cells by the anomalous activation of mitogen-activated protein kinase (MAPK) via a signaling pathway that included Ras, Raf-1 and MAPK kinase-1. We report here the effect of bufalin on c-Jun N-terminal protein kinase (JNK), a member of the MAPK family, and on the signaling pathway downstream of MAPKs in U937 cells. When U937 cells were treated with 10(-8) M bufalin, the activity of JNK1 was markedly elevated 3 h after the start of treatment and remained so for 9 h. This activation of JNK and the induction of apoptosis by bufalin were suppressed by expression of antisense mRNA for MAPK kinase-1. c-Jun was translocated from the cytoplasm to the nucleus after treatment of U937 cells with bufalin. The transcriptional activity of AP-1 was transiently enhanced by the treatment with bufalin and this activation was suppressed by the expression of antisense mRNA for MAPK kinase-1. Both curcumin (1,7-bis[4-hydroxy-3-methoxy-phenyl]-1,6-heptadiene-3,5-dione), an inhibitor of the biosynthesis of AP-1, and the expression of dominant negative c-Jun inhibited the activation of AP-1 and the induction of apoptosis by bufalin. Expression of a constitutively active mutant form of MAPK kinase-1 induced the activation of AP-1 and subsequent apoptosis in U937 cells. These results suggest that the activation of AP-1 via a MAPK cascade that includes JNK is required for the induction of apoptosis by bufalin in U937 cells.

Immunocytochemical localization of nicotinic acetylcholine receptor in the rat cerebellar cortex

Although nicotinic acetylcholine receptors (nAChRs) have been reported to function in the cerebellar cortex, nicotinic acetylcholine receptor subtypes contributing to nicotinic currents in the cortex have not been well characterized at the subcellular level. This study deals with immunocytochemical localization of the nicotinic acetylcholine receptor alpha4 subunit using a monoclonal antibody against the alpha4 subunit. Alpha4-LI (alpha4-like immunoreactivity) was detected in the cell bodies of molecular, Purkinje cell and granular layers. In particular, the cell bodies of Purkinje cells were extensively immunostained. In Purkinje cells, alpha4-LI was found in perikarya mainly associated with rough endoplasmic reticulum, plasma membrane, and cytoplasmic matrix. At higher magnification, the immunoreaction product was densely localized along with somatic plasma membranes at the axo-somatic synapse and the plasma membranes at extrasynaptic regions of cell bodies. Alpha4-LI was also found in the axon terminals which form synapses with Purkinje cells. In the granular layer, somatic cell membranes of granular cells were immunostained. These morphological observations suggest that alpha4-containing nAChRs contribute nicotinic currents reported in Purkinje cells, and that presynaptic alpha4-containing nAChRs regulate the release of neurotransmitters on the axon terminals found near Purkinje cells.

Neuronal nicotinic acetylcholine receptor in the hypothalamus: morphological diversity and neuroendocrine regulations

The subcellular localization and functional significance of neuronal nicotinic acetylcholine receptor alpha4-subunits were investigated in the rat hypothalamic supraoptic nucleus. A high level of alpha4 mRNA expression was found in the magnocellular neurons in the supraoptic nucleus. Strong immunoreactitivy for alpha4 in neurons of the supraoptic nucleus was detected in the rough endoplasmic reticulum and cytoplasmic matrix, although it was very weak in the Golgi apparatus, except for the transport vesicles. Immunoreactivity for alpha4 was detected in both the pre-synaptic axon terminals and post-synaptic axon terminals. A high level of signals for vasopressin mRNA was detected in the supraoptic nucleus after the animals were injected s.c. with nicotine. These findings suggest that alpha4-containing subtypes are synthesized in the rough endoplasmic reticulum and transported to the plasma membrane and serve as pre- and post-synaptic nicotinic acetylcholine receptors. Nicotine may up-regulate vasopressin gene expression in the supraoptic nucleus, acting through nicotinic acetylcholine receptors.

Bufalin reduces the level of topoisomerase II in human leukemia cells and affects the cytotoxicity of anticancer drugs

When human leukemia HL-60 cells were treated with 10(-7) M bufalin, the amounts of both topoisomerase (topo) II alpha and II beta and the activity of topo II decreased markedly and were almost undetectable 18 h after the start of treatment. The level of topo II mRNA started to decrease immediately after the start of treatment with bufalin, with a subsequent decrease in the amount of topo II alpha protein. These changes preceded the fragmentation of DNA, a typical feature of apoptosis. The results suggest that bufalin caused a marked decrease in the steady-state level of topo II alpha mRNA, which led to a decrease in the amount and activity of the enzyme and to the induction of apoptosis. A reduction in the level of topo II alpha by bufalin was also observed in other lines of human leukemia cells such as ML1 and U937. The results were exploited to potentiate the effects of cisplatin and retinoic acid (RA) on HL-60 cells: pretreatment of HL-60 cells with 10(-7) M bufalin for 6 h increased the inhibitory effects of cisplatin and RA on cell growth and enhanced the induction of cell death.