Effects of dizocilpine pretreatment on parvalbumin immunoreactivity and Fos expression after cerebral ischemia in the hippocampus of the Mongolian gerbil

The mechanisms of ischemic neuronal death have been focused on glutamate receptor activation and subsequent elevation of intracellular Ca2+ concentration. The purpose of this study was to evaluate the effects of dizocilpine, an NMDA receptor antagonist, pretreatment on Fos expression and parvalbumin (PV, calcium binding protein) immunoreactivity in the hippocampus of the mongolian gerbil after global ischemic insults. The number of PV-immunoreactive (PV-ir) neurons in CA1 were significantly decreased from 1 day after cerebral ischemia, while dizocilpine pretreatment completely suppressed the loss of PV-ir neurons in CA1. Dizocilpine pretreatment also protected the structural loss of microtubule-associated protein 2 immunoreactivity in CA1 after ischemic insults. In addition, dizocilpine pretreatment increased Fos expression in both hippocampal CA3 and CA4 after 3 hr ischemic reperfusion as compared to that of the saline pretreated group. Subsequently, the Fos-defined cellular activity of PV-ir neurons was slightly increased by dizocilpine pretreatment in the hippocampal area. This study demonstrated that NMDA receptor mediated calcium influx was associated with the loss of PV-ir neurons in CA1 hippocampal region, and that dizocilpine pretreatment increased Fos expression and the neuronal activity of PV-ir neurons in the non-vulnerable region of hippocampus after cerebral ischemia. Based on this data, we conclude that the protective effect of dizocilpine may be induced by the regulation of calcium overload, or by the upregulation of a neuroregenerative initiator such as Fos protein.

Ca2+ influx mediates apoptosis induced by 4-aminopyridine, a K+ channel blocker, in HepG2 human hepatoblastoma cells

Apoptosis appears to be implicated in the pathogenesis and therapeutic applications of cancer. In this study we investigated the induction of apoptosis by 4-aminopyridine (4-AP), a K(+) channel blocker, and its mechanism in HepG2 human hepatoblastoma cells. 4-AP reduced cell viability and induced DNA fragmentation, a hallmark of apoptosis, in a dose-dependent manner. In addition, 4-AP induced a sustained increase in intracellular Ca(2+) concentration, which was completely inhibited by the extracellular Ca(2+) chelation with EGTA. 4-AP also induced Mn(2+) influx, indicating that the 4-AP-induced increased intracellular Ca(2+) levels were due to activation of Ca(2+) influx pathway. 4-AP also depolarized membrane potential that was measured by using di-O-C(5)(3), a voltage-sensitive fluorescent dye. 4-AP-induced Ca(2+) influx was significantly inhibited not by voltage-operative Ca(2+) channel blockers (nifedipine or verapamil), but by flufenamic acid (FA), a known nonselective cation channel blocker. Quantitative analysis of apoptosis by the flow cytometry revealed that treatment with either FA or BAPTA, an intracellular Ca(2+) chelator, significantly inhibited the 4-AP-induced apoptosis. Taken together, these results suggest that the observed 4-AP-induced apoptosis in the HepG2 cells may result from Ca(2+) influx through the activation of voltage-sensitive Ca(2+)-permeable non-selective cation channels. These results further suggest that membrane potential change by modulation of K(+) channel activity may be involved in the mechanism of apoptosis in human hepatoma cells.

Modulation of lysophosphatidic acid-induced Cl- currents by protein kinases A and C in the Xenopus oocyte

The roles of protein kinase C (PKC) and protein kinase A (PKA) in the regulation of lysophosphatidic acid (LPA)-induced Cl- currents in Xenopus oocytes were examined. PKC activation by phorbol 12-myristate 13-acetate (PMA) treatment completely blocked LPA-induced Cl- currents by inhibiting inositol 1,4,5-trisphosphate (IP3) elevation. This inhibitory effect of PMA on the LPA response was blocked by pretreatment of oocytes with staurosporine and 3-[N-(dimethylamino)propyl-3-indiolyll-4-[3-indolyl]maleimide (GF109203X), PKC inhibitors. In addition, treatment of oocytes with GF109203X enhanced the LPA response by increasing IP3 production. Elevation of the intracellular adenosine 3',5'-cyclic monophosphate (cAMP) concentration by treating oocytes with either forskolin (FK) plus isobutylmethylxanthine (IBMX) or 2'-O-dibutyryl-cAMP (dB-cAMP) reduced LPA-induced Cl- currents. The effect of activation of the cAMP pathway appears to be mediated by PKA, since treatment of oocytes with FK plus IBMX or dB-cAMP enhanced PKA activity. Furthermore, the inhibitory effect of dB-cAMP on the LPA response was blocked by treatment of oocytes with N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulframide-2 HCl (H-89), a selective inhibitor of PKA. Both FK plus IBMX and dB-cAMP treatment reduced IP3 generation in response to LPA stimulation. Inhibition of PKA activity with H-89 or Rp-cyclic 3',5'-hydrogen phosphorothioate adenosine triethylammonium had no effect on LPA-induced Cl- currents. Finally, inhibition of the LPA response by activation of PKA was independent of extracellular Ca2+. These results demonstrate that both PKC and PKA play active roles in modulating the LPA-induced signaling pathway.

Cloning and functional characterization of a Caenorhabditis elegans muscarinic acetylcholine receptor

A cDNA clone encoding a muscarinic acetylcholine receptor (mAChR) has been isolated from the nematode Caenorhabditis elegans. The nematode mAChR, consisted of 585 amino acids, displays a high degree of amino acid sequence homology to other invertebrate and vertebrate mAChRs. Excluding a highly variable middle portion of the third intracellular loop, the C. elegans mAChR shares about 51% amino acid sequence identity with a Drosophila mAChR and 42-44% identity with human m1-m5 mAChR subtypes. Comparison of the cDNA sequence with the corresponding genomic sequence reveals that the C. elegans mAChR gene contains ten introns, eight of them in the coding region. Pharmacological profiles of the C. elegans mAChR expressed in Chinese hamster ovary (CHO) cells were shown to be similar to those of mammalian counterparts, indicating that ligand binding domains of the receptor have been conserved during evolution. When this cloned receptor was expressed in Xenopus oocytes, acetylcholine evoked a transient Cl- current. Furthermore, activation of the receptor with oxotremorine, acetylcholine or carbachol resulted in the stimulation of phosphatidylinositol metabolism in CHO cells, suggesting that the receptor is coupled to phospholipase C activation.

Systemic mononuclear inflammatory vasculopathy associated with Sjögren's syndrome in a patient with primary biliary cirrhosis

We report a 46-year-old woman with primary biliary cirrhosis (PBC) presenting with Sjögren's syndrome and systemic mononuclear inflammatory vasculopathy. Biopsy specimens of sural nerve showed findings consistent with vasculitic neuropathy. Perivascular inflammatory mononuclear cell infiltration was observed on muscle biopsy specimen. The findings of abdominal computed tomography and brain magnetic resonance imaging were suggestive of vasculitis. Clinical manifestations and radiologic findings were improved after high dose prednisolone therapy.

Usefulness of MR imaging for diseases of the small intestine: comparison with CT

OBJECTIVE

To evaluate the usefulness of MR imaging for diseases of the small intestine, emphasizing a comparison with CT.

MATERIALS AND METHODS

Thirty-four patients who underwent both CT and MR imaging using FLASH 2D and HASTE sequences were analyzed. All patients had various small bowel diseases with variable association of peritoneal lesions. We compared the detectabilities of CT and MR imaging using different MR pulse sequences. The capability for analyzing the characteristics of small intestinal disease was also compared.

RESULTS

MR imaging was nearly equal to CT for detecting intraluminal or peritoneal masses, lesions in the bowel and mesentery, and small bowel obstruction, but was definitely inferior for detecting omental lesions. The most successful MR imaging sequence was HASTE for demonstrating bowel wall thickening, coronal FLASH 2D for mesenteric lesions, and axial FLASH 2D for omental lesions. MR imaging yielded greater information than CT in six of 12 inflammatory bowel diseases, while it was equal to CT in six of seven neoplasms and inferior in five of seven mesenteric ischemia. In determining the primary causes of 15 intestinal obstructions, MR imaging was correct in 11 (73%) and CT in nine (60%) patients.

CONCLUSION

MR imaging can serve as an alternative diagnostic tool for patients with suspected inflammatory bowel disease, small intestinal neoplasm or obstruction.

Superoxide dismutase gene expression and activity in the brain of spontaneously hypertensive rats and normotensive rats

OBJECTIVE

To determine if changes in superoxide dismutase (SOD) in the brain occur in the hypertensive state.

METHODS

We compared the levels of the two main subtypes of this enzyme in spontaneously hypertensive rats (SHR) with age-matched normotensive Wistar Kyoto (WKY) rats using enzyme activity estimation, Western blotting for enzyme contents, and Northern blotting of mRNA level. Five discrete brain regions, cerebrocortex, hypothalamus, hippocampus, the remaining non-cortex cerebrum (NCC area), and cerebellum, were employed for comparison in 30-31 weeks old rats.

RESULTS

A lower level of both Mn-SOD activity and Mn-SOD mRNA expression was found in all areas of the brain of SHR as compared with WKY rats. Also, the mRNA levels of Cu, Zn-SOD in the brain of SHR differed from WKY rats in parallel to the enzyme activities. The activity and mRNA expression of Cu, Zn-SOD were lower in the hypothalamus and cerebellum of SHR but the mRNA level and the activity in hippocampus were significantly higher in the SHR compared to WKY rats. No differences for Cu, Zn-SOD were observed in cerebrocortex or NCC area in the two species. However, the amount of SOD enzyme subtypes, determined by Western blotting analysis, was not different between SHR and WKY rats.

CONCLUSIONS

The results indicate a lower gene expression and less activity of Mn-SOD in SHR brain. This alternation of SOD may be one of the important factors for the vulnerability of the brain from oxygen free radicals or may be related to the pathogenesis of hypertension in this species.

The effects of various intensities and durations of exercise with and without glucose in milk ingestion on postexercise oxygen consumption

BACKGROUND

The purpose of this study was to compare the 2-hr excess postexercise oxygen consumption (EPOC), respiratory exchange ratio (RER), and rectal temperature (RT) after four-exercise bouts of varying intensity and duration, with and without glucose in milk (GM) ingestion.

METHODS

EXPERIMENTAL DESIGN

subjects completed the exercise tests in random order 4 times on the same weekday. The four experimental exercise conditions were low intensity, long duration with GM (LL & GM), low intensity, long duration without GM (LL & NGM), high intensity, short duration with GM (HS & GM), and high intensity, short duration without GM (HS & NGM).

PARTICIPANTS

ten male college students (20.8 +/- 0.6) yrs participated voluntarily. Measures. Two-way repeated measures ANOVA (exercise condition x time) was used to compare the variables.

RESULTS

Mean EPOC for the 2-hr postexercise period for HS & GM (211.5 ml O2/kg) was significantly greater than EPOC for HS & NGM (154.8 ml O2/kg), LL & GM (140.4 ml O2/kg) and LL & NGM (125.2 ml O2/kg). Mean recovery oxygen uptakes were 6.4, 5.7, 4.5, and 4.2 ml/min/kg with HS & GM, HS & NGM, LL & GM and LL & NGM, respectively. Mean RERs for high intensity exercises were significantly lower than RERs for low intensity exercises during the recovery period. Mean RT for HS & GM (37.60 degrees C) and HS & NGM (37.43 degrees C) were significantly higher than RT for LL & GM (37.19 degrees C) and LL & NGM (37.15 degrees C) during the recovery period.

CONCLUSION

These results suggest that preexercise intake of GM increases EPOC above that observed in the fasting condition, and high intensity short duration exercise increases fat oxidation during recovery period more than low intensity long duration exercise.

Involvement of Ca2+ influx in the mechanism of tamoxifen-induced apoptosis in HepG2 human hepatoblastoma cells

The signaling mechanism of tamoxifen (TAM)-induced apoptosis was investigated in HepG2 human hepatoblastoma cells which do not express the estrogen receptor (ER). TAM induced cytotoxicity and DNA fragmentation, a hallmark of apoptosis, in a dose-dependent manner. TAM increased the intracellular concentration of Ca2+. This effect was completely inhibited by the extracellular Ca2+ chelation with EGTA. TAM also induced a Mn2+ influx, indicating that TAM activated Ca2+ influx pathways. This action of TAM was significantly inhibited by flufenamic acid (FA), a known non-selective cation channel blocker. Quantitative analysis of apoptosis by flow cytometry revealed that treatment with either FA or BAPTA, an intracellular Ca2+ chelator, significantly inhibited TAM-induced apoptosis. These results suggest that intracellular Ca2+ signals may play a central role in the mechanism of the TAM-induced apoptotic cell death in ER-negative HepG2 cells.

Detection of tumor cell contamination in peripheral blood by RT-PCR in gastrointestinal cancer patients

We analyzed the peripheral blood of patients with gastrointestinal tract cancer at different stages to assess the presence of carcinoembryonic antigen (CEA) mRNA by reverse transcriptase-polymerase chain reaction (RT-PCR), which we used as an indicator for micrometastatic malignant cells. A total of 35 gastric, 24 colorectal, 4 esophageal and 4 biliary tract cancer patients and nine normal healthy subjects were studied. No CEA mRNA was detected in the nine normal healthy volunteers. CEA mRNA was detected in 100% (10/10) of metastatic, 33.3% (3/9) of early gastric cancer (EGC), and 18.8% (3/16) resectable gastric cancer patients, respectively. In colorectal cancer, 55.6% (5/9) of metastatic cancers were positive for CEA mRNA, and 26.7% (4/15) Duke stage B/C showed positive. One patient with stage III gastric cancer who was negative CEA mRNA initially and turned positive during follow-up, developed multiple bone metastasis one month later. Another stage III patient, who was positive for CEA mRNA, preoperatively revealed early relapse in two months. These results suggest that the identification of circulating tumor cells using RT-PCR for the detection of CEA mRNA is feasible and this analysis may be a promising tool for early detection of micrometastatic circulating malignant cells in patients with gastrointestinal tract cancer.

Pharmacological and functional characterization of bradykinin receptors in rat cultured vascular smooth muscle cells

The pharmacological properties of bradykinin receptors were characterized in rat cultured vascular smooth muscle cells (VSMCs) using [3H]-bradykinin as a ligand. Analysis of binding isotherms gave an apparent equilibrium dissociation constant (K(D)) of 1.2 +/- 0.2 nM and a maximum receptor density (Bmax) of 47.3 +/- 4.4 fmol/mg protein. The specific binding of [3H]-bradykinin to VSMCs was inhibited by the B2 receptor-selective agonists (bradykinin and kallidin) and antagonists ([D-Arg0, Hyp3, Thi5, D-Tic7, Oic8]-bradykinin (Hoe 140) and [D-Arg0, Hyp3, Thi(5,8), D-Phe7]-bradykinin) with an order of potency as kallidin = bradykinin = Hoe 140 > [D-Arg0, Hyp3, Thi(5,8), D-Phe7]-bradykinin, but not by a B1 receptor-selective agonist (des-Arg9-bradykinin) and antagonist ([Leu8, des-Arg9]-bradykinin). Stimulation of VSMCs by bradykinin produced a concentration-dependent inositol phosphate (IP) accumulation, and initial transient peak of [Ca2+]i with half-maximal responses (pEC50) were 7.53 and 7.69, respectively. B2 receptor-selective antagonists (Hoe 140 and [D-Arg0, Hyp3, Thi(5,8), D-Phe7]-bradykinin) significantly antagonized the bradykinin-induced responses with pK(B) values of 8.3-8.7 and 7.2-7.9, respectively. Pretreatment of VSMCs with pertussis toxin (100 ng/ml, 24 h) did not alter the bradykinin-induced inositol phosphate accumulation and [Ca2+]i changes in VSMCs. Removal of external Ca2+ led to a significant attenuation of responses induced by bradykinin. Influx of external Ca2+ was required for the bradykinin-induced responses, since Ca2+-channel blockers, nifedipine, verapamil, and Ni2+, partially inhibited the bradykinin-induced IP accumulation and Ca2+ mobilization. These results demonstrate that bradykinin stimulates phosphoinositide hydrolysis and Ca2+ mobilization via a pertussis toxin-insensitive G-protein in rat VSMCs. Bradykinin B2 receptors may be predominantly mediating IP accumulation and subsequently induction of Ca2+ mobilization may function as the transducing mechanism for bradykinin-stimulated contraction of vascular smooth muscle.

Regulatory mechanism of polarized membrane transport by glucocorticoid in renal proximal tubule cells: involvement of [Ca2+]i

We examined the effect of glucocorticoids on brush border membrane transporters and, furthermore, the involvement of Ca2+ in its action in the primary cultured rabbit renal proximal tubule cells (PTCs). Dexamethasone (DEX, 10(-9) M) decreased Pi uptake by 17%; whereas DEX affected neither alpha-methyl-glucopyranoside (alpha-MG) uptake nor Na+ uptake. The DEX-induced inhibition of Pi uptake was due to a decrease of V(max). In contrast, other steroid hormones such as progesterone, testosterone, and 17beta-estradiol (10(-9) M) did not induce inhibition of Pi uptake. In order to examine the involvement of Ca2+ in DEX-induced inhibition of Pi uptake, PTCs were treated with A 23187 (10(-6) M, Ca2+ ionophore). A 23187 also inhibited Pi uptake, mimicking DEX action in Pi uptake. Treatments with W-7 (10(-4) M, calmodulin dependent kinase inhibitor), KN-62 (10(-6) M, Ca2+/calmodulin-dependent protein kinase II inhibitor), and BAPTA/AM (10(-6) M) or TMB-8 (10(-4) M) (intracellular Ca2+ mobilization blockers) blocked the DEX-induced inhibition of Pi uptake. However, nifedifine, methoxyverapamil (10(-6) M, L-type Ca2+ channel blockers), and EGTA (1 mM, extracellular Ca2+ chelator) did not block it. In conclusion, DEX inhibited Pi uptake via, in part, Ca2+/calmodulin pathway mediated by intracellular Ca2+ mobilization in the PTCs.

PhoB-dependent transcriptional activation of the iciA gene during starvation for phosphate in Escherichia coli

The IciA protein from Escherichia coli has been shown specifically to inhibit the in vitro initiation of chromosomal DNA replication. However, the in vivo role of IciA has not yet been established. In order to investigate the in vivo function of this protein, expression of the iciA gene was studied by monitoring the beta-galactosidase activity specified by an iciA promoter-lacZ fusion inserted into the chromosome. Among the conditions tested (carbon starvation, the stringent response, phosphate starvation, and the SOS response), only phosphate depletion increased iciA expression. Supplementation of phosphate-depleted cultures with inorganic phosphate reduced the beta-galactosidase activity to basal levels. Enhanced expression of iciA-lacZ was dependent upon the PhoB protein. PhoB is known to be a transcriptional activator of the Pho regulon, expression of which is activated during phosphate starvation. It was also found that the iciA promoter contains a PhoB protein-binding sequence, termed the Pho box, which is necessary for the activation of genes of the Pho regulon. These results suggest that the iciA gene is a member of the Pho regulon.

A convergent liquid-phase synthesis of salmon calcitonin

Salmon calcitonin (sCT) was prepared in good yield and high purity by the condensation of Nalpha-Boc-cyclic decapeptide, Boc-C1SNLSTC7VLG-OH (1,7-disulfide), with protected docosapeptide (Psc)LSQE(OPse)LHK(Psc)LQTYPRTNTGSGTP-NH2 x 3TFA, followed by deprotection of Boc with trifluoroacetic acid and Psc/Pse with piperidine. The 2-(phenylsulfonyl)ethoxycarbonyl (Psc) and 2-(phenylsulfonyl)ethyl (Pse) protecting groups were recently developed. The two peptides were built up by stepwise and fragment condensation using appropriate Nalpha-Boc-amino acids and subsequent deprotection in solution. The synthetic sCT exhibited hypocalcemic potency of more than 4000 IU/mg in rats.

Malignant ectopic thymoma in the neck: a case report

We report a case of malignant ectopic thymoma in the neck. Contrast-enhanced CT of the neck showed a well-defined inhomogeneously enhancing mass in the left jugulodigastric chain. One year after surgery, the mass had metastasized to the tongue base, and CT of the neck showed an ill-defined densely enhancing mass with lymphadenopathy.

Inhibition of activation of nuclear factor kappaB is responsible for inhibition of inducible nitric oxide synthase expression by higenamine, an active component of aconite root

Effects of higenamine on nitric oxide (NO) production and inducible NO synthase (iNOS) mRNA expression (RAW 264.7 cells), on vascular reactivity in vitro and in vivo (rats), and on survival rates (mice) and serum nitrite/nitrate levels (rats) were investigated by using last lipopolysaccharide (LPS) plus interferon (IFN)-gamma. Higenamine concentration-dependently inhibited NO production and inducible NO synthase mRNA in RAW 264.7 cells, in which the IC(50) was 53 microM. Higenamine (10 mg/kg i.p.) administered 90 min before LPS (5 mg/kg i.v.) prevented not only LPS-induced hypotension but also pressor response to norepinephrine (1 microgram/kg) in rats. Incubation of thoracic aorta with LPS (300 ng/ml) for 8 h in vitro resulted in suppression of the vasoconstrictor effects to phenylephrine, which was prevented by coincubation with higenamine. The survival rate to endotoxin in mice was significantly (P <.01) increased by the presence of higenamine in the LPS-treated group up to 48 h. Serum nitrite/nitrate levels were significantly (P <.05) reduced by higenamine in LPS-treated rats. Finally, higenamine inhibited the activation of nuclear factor kappaB in RAW 264.7 cells due to LPS + IFN-gamma by mobility shift assays. Taken together, these data strongly suggest that higenamine inhibits iNOS expression by inhibiting nuclear factor kappaB activation by LPS + IFN-gamma, which may be beneficial in inflammatory diseases in which enhanced formation of NO is the main causative factor. Furthermore, due to positive inotropic action, higenamine may be more effective in a condition where myocardial contractility is likely to depress, such as in septic shock and/or endotoxin-induced inflammatory disorders.

c-Ki-ras mutations in colorectal adenocarcinomas from a country with a rapidly changing colorectal cancer incidence

We have examined the incidence of mutation of the c-Ki-ras proto-oncogene in colorectal adenocarcinomas from two different time periods, namely 1962-1966 and 1994-1996. The first cohort of samples consisted of formalin-fixed, archival paraffin block and represent the oldest colorectal cancer samples for which ras mutation has been examined, while the second cohort of tumours were fresh, flash-frozen samples representative of genetic events occurring in contemporary times. Analysis of mutation status was undertaken by a mismatch-specific oligonucleotide hybridization analysis of exon 1 of the c-Ki-ras proto-oncogene after amplification by the polymerase chain reaction. Mutations in codon 12 or 13 of c-Ki-ras were detected in 28% (14/50) of contemporary samples, a figure consistent with locally established mutation rates. In contrast no mutation was detected in any of the 18 samples from the earlier period, a result that is statistically significant (P = 0.007). Age-standardized rates of colorectal cancer in Singapore have seen a marked increase over the last 30 years, and for the first time we have shown that such an increase in colorectal cancer is associated, at least in part with an increase in incidence of a specific mutagenic change.

Chondroblastoma: MR characteristics with pathologic correlation

PURPOSE

The purpose of this study was to describe the MR findings of chondroblastoma with pathologic correlation.

METHOD

In 22 patients with pathologically proven chondroblastoma, MR signal characteristics were correlated with pathological findings.

RESULTS

On T2-weighted images, 12 (55%) lesions were hyperintense with hypointense areas in 9 lesions, whereas 10 (45%) were hypointense. Therefore, 19 of 22 (86%) lesions with pathologic correlation had hypointense areas entirely (n = 10) or partly (n = 9) on T2-weighted images. On gadolinium-enhanced images, 13 (59%) lesions showed lobular enhancement and 9 (41%) showed marginal and septal enhancement. Low signal intensity on T2-weighted MR images was most strongly associated with an abundance of immature chondroid matrix, hypercellularity of the chondroblasts, calcifications, and hemosiderin on histology.

CONCLUSION

Chondroblastoma was found to show hypointense portions on T2-weighted images. Signal intensity on T1- and T2-weighted MR images in chondroblastoma was dependent on the amounts of histopathological components.

Radiation augments a sequential program of differentiation in PKC inhibitor- pretreated mouse epidermal cells

The aim of this study was to determine whether gamma-rays affect differentiation in mouse epidermal cells. After a pre-treatment with the PKC inhibitor staurosporin (STS) or 1-(5-isoquinolinesulfomyl)-2-methylpiperazine (H7), gamma-rays were irradiated with or without an elevation of 0.12 mM Ca2+ and expressions of differentiation markers and each PKC isozyme were examined in normal primary and v-rasHa transformed mouse keratinocytes. Gamma-rays induced the expressions of differentiation markers of keratin 1 and 10 (K1 and 10), filaggrin, loricrin and SPR-1 in normal keratinocytes when the Ca2+ concentration was increased, and these phenomena were augmented in H7 pretreated cells. Similar results were obtained in STS pretreated cells; in this case, gamma-rays enhanced the expressions of the differentiation markers even without an elevated Ca2+ concentration. In v-rasHa transformed cells, gamma-rays induced the expression of differentiation markers not only at 0.05 mM Ca2+, but in 0.12 mM Ca(2+)-shifted cells, and in H7 pretreated cells, these phenomena were augmented. The translocation of PKC alpha to the particulate fraction was seen in H7 pretreated normal keratinocytes. Radiation also induced PKC alpha expression in STS pretreated cells, independent of Ca(2+)-shift, as well as altered expressions of PKC delta and -eta, while expressions of PKC alpha, -delta, -epsilon, and -eta were enhanced in v-rasHa transformed cells. In conclusion, gamma-rays augmented the expressions of both spinous and granular differentiation markers in normal and v-rasHa transformed keratinocytes and this effect was augmented when PKC inhibitors were used, which may be mediated by the cellular redistribution of PKC isozymes.

Interaction of radicicol with members of the heat shock protein 90 family of molecular chaperones

The Hsp90 family of proteins in mammalian cells consists of Hsp90 alpha and beta, Grp94, and Trap-1 (Hsp75). Radicicol, an antifungal antibiotic that inhibits various signal transduction proteins such as v-src, ras, Raf-1, and mos, was found to bind to Hsp90, thus making it the prototype of a second class of Hsp90 inhibitors, distinct from the chemically unrelated benzoquinone ansamycins. We have used two novel methods to immobilize radicicol, allowing for detailed analyses of drug-protein interactions. Using these two approaches, we have studied binding of the drug to N-terminal Hsp90 point mutants expressed by in vitro translation. The results point to important drug contacts with amino acids inside the N-terminal ATP/ADP-binding pocket region and show subtle differences when compared with geldanamycin binding. Radicicol binds more strongly to Hsp90 than to Grp94, the Hsp90 homolog that resides in the endoplasmic reticulum. In contrast to Hsp90, binding of radicicol to Grp94 requires both the N-terminal ATP/ADP-binding domain as well as the adjacent negatively charged region. Radicicol also specifically binds to yeast Hsp90, Escherichia coli HtpG, and a newly described tumor necrosis factor receptor-interacting protein, Trap-1, with greater homology to bacterial HtpG than to Hsp90. Thus, the radicicol-binding site appears to be specific to and is conserved in all members of the Hsp90 family of molecular chaperones from bacteria to mammals, but is not present in other molecular chaperones with nucleotide-binding domains.

CT features of abdominal manifestations of primary antiphospholipid syndrome

PURPOSE

The purpose of this work was to evaluate the CT features of the abdominal manifestations of primary antiphospholipid syndrome (PAPS).

METHOD

Of the 32 patients who were confirmed to have PAPS among 751 patients with elevated antiphospholipid antibodies during a 2 year period, we retrospectively reviewed the 14 patients who underwent abdominal CT. The clinical indications for abdominal CT included abdominal pain, abdominal distension, or lower leg swelling. CT findings were analyzed with regard to the abdominal vascular system and abdominal organ involvement patterns as well as ancillary findings.

RESULTS

Of the 14 patients with PAPS, 10 had involvement of the venous system (72%), 2 of the arterial system (14%), and 2 of both systems (14%). Of the 12 patients who had venous system involvement, 4 had thrombosis in the inferior vena cava (IVC), 2 in both the IVC and the hepatic vein, 1 in the IVC and splenic and portal veins, 1 in the IVC and hepatic and adrenal veins, 1 in the hepatic, portal, and renal veins, and 3 in the portal and superior mesenteric veins. Budd-Chiari syndrome developed in five of the nine patients who had thrombosis of the IVC or hepatic vein. Arterial thrombosis was noted in four patients, hepatic artery in two, aorta in one, renal artery in one, pancreatic arcade in one, and splenic artery in one, with infarct of multiple organs including the liver, jejunum, colon, kidney, and adrenal gland. Seven of the 14 patients (50%) manifested thrombosis or infarct of multiple extra-abdominal organs.

CONCLUSION

PAPS should be included in the differential diagnosis when CT demonstrates infarcts in multiple organs or patients have recurrent episodes of venous or arterial thrombosis.

Inhibition of human malignant glioma growth in vivo by human recombinant plasminogen kringles 1-3

Human malignant gliomas are highly vascularized and aggressive tumors. Angiogenesis inhibitors have been shown to induce regression of a variety of primary and metastatic tumors in vivo. However, their usefulness in treating brain tumors is not well understood. Angiostatin, a multiple kringle (1-4 of 5)-containing fragment of plasminogen, is one of the highly effective natural cryptic angiogenesis inhibitors. In our study, the therapeutic efficacy of non-glycosylated and small molecular size recombinant kringles 1-3 (rPK1-3) was examined in the treatment of brain tumors generated by stereotactic intracerebral implantation of U-87 human glioma cells in nude mice. Mice bearing tumors 7 days post-implant were treated daily with rPK1-3 (100 mg/kg) s.c. for 21 days. Treated animals showed suppressed brain tumor growth by greater than 71.2% along with a 3-fold increase of apoptotic index and suppressed vascularization by 78.9%, without any observable signs of toxicity. Analysis of bFGF and VEGF expression in the tumors of treated animals using immuno-histochemical methods showed near complete absence of growth factors. Our results indicate that the non-glycosylated, small molecular size rPK1-3 is an efficient tumoristatic agent for the treatment of intracranial human glioma xenografts in mice and might provide new strategies for the treatment of brain tumors.

Determination of enzymatic activity and properties of secretory phospholipase A2 by capillary electrophoresis

A capillary electrophoretic (CE) system coupled with a diode array UV detector was used for the assay of secretory phospholipase A2 (sPLA2) activity. This method is based on monitoring both the breakdown of substrates and the formation of products simultaneously using micellar electrokinetic chromatographic techniques. Under our developed separation conditions, we analyzed the substrates and products quantitatively, and investigated enzyme activity as a function of reaction time and presence of enzyme activator or inhibitor. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was also utilized to confirm the phosphatidylcholine, a substrate of sPLA2. In order to test the feasibility of the developed method for measurement of enzymatic activity, we compared it to the conventional radioactive assay method for sPLA2. On the basis of our results, the conventional method can be complemented, or even replaced, by this new CE method which possesses the advantages of short analysis time, use of non-radiolabeled and inexpensive substrates, simple measurement of enzymatic activity, and exact quantitation of substrate and product.

Glibenclamide induces apoptosis through inhibition of cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channels and intracellular Ca(2+) release in HepG2 human hepatoblastoma cells

Glibenclamide, an inhibitor of cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channels, induced apoptosis in a dose- and time-dependent manner in HepG2 human hepatoblastoma cells. Glibenclamide increased intracellular Ca(2+) concentration, which was significantly inhibited by Ca(2+) release blockers dantrolene and TMB-8. BAPTA/AM, an intracellular Ca(2+) chelator, and the Ca(2+) release blockers significantly inhibited glibenclamide-induced apoptosis. Glibanclamide also increased intracellular Cl(-) concentration, which was significantly blocked by CFTR Cl(-) channel activators levamisole and bromotetramisole. These activators also significantly inhibited both intracellular Ca(2+) release and apoptosis induced by glibenclamide. The expression of CFTR protein in the cells was confirmed by Western blot analysis. These results suggest that glibenclamide induced apoptosis through inhibition of CFTR Cl(-) channels and intracellular Ca(2+) release and that this protein may be a good target for treatment of human hepatomas.