Intracellular calcium antagonist protects cultured peritoneal macrophages against anthrax lethal toxin-induced cytotoxicity

The lethal toxin of Bacillus anthracis is central to the pathogenesis of anthrax. Using primary cultures of mouse peritoneal macrophages, we have demonstrated that intracellular calcium release inhibitors protect against anthrax lethal toxin-induced cytotoxicity. The cytolytic effect of anthrax lethal toxin was markedly reduced by dantrolene, an inhibitor of calcium release from intracellular calcium stores. Pretreatment of macrophages with cyclosporin A, which has been shown to be a potent inhibitor of calcium release from mitochondria, also protected cells against cytotoxicity. These results indicate that calcium release from intracellular store may be an essential step for the propagation of anthrax lethal toxin-induced cell damage in macrophages. Thus our findings suggest that dantrolene, cyclosporin A, and possibly other drugs affecting intracellular calcium pools might be effectively preventing the toxicity from anthrax lethal toxin.

Haloperidol and clozapine increase neural activity in the rat prefrontal cortex

Haloperidol and clozapine have been widely used to alleviate schizophrenic symptoms, but their physiological effects in the prefrontal cortex (PFC) are not known. Effects of haloperidol and clozapine on single unit activity were investigated in the medial PFC of anesthetized rats. Injection (intraperitoneal) of haloperidol (1 mg/kg) or clozapine (20 mg/kg) significantly elevated discharge rates of PFC neurons. Considering that hypofrontality is one characteristic of schizophrenic symptoms, these results raise the possibility that enhancement of PFC neural activity contributes to therapeutic effects of haloperidol and clozapine.

Adipose-selective targeting of the GLUT4 gene impairs insulin action in muscle and liver

The earliest defect in developing type 2 diabetes is insulin resistance, characterized by decreased glucose transport and metabolism in muscle and adipocytes. The glucose transporter GLUT4 mediates insulin-stimulated glucose uptake in adipocytes and muscle by rapidly moving from intracellular storage sites to the plasma membrane. In insulin-resistant states such as obesity and type 2 diabetes, GLUT4 expression is decreased in adipose tissue but preserved in muscle. Because skeletal muscle is the main site of insulin-stimulated glucose uptake, the role of adipose tissue GLUT4 downregulation in the pathogenesis of insulin resistance and diabetes is unclear. To determine the role of adipose GLUT4 in glucose homeostasis, we used Cre/loxP DNA recombination to generate mice with adipose-selective reduction of GLUT4 (G4A-/-). Here we show that these mice have normal growth and adipose mass despite markedly impaired insulin-stimulated glucose uptake in adipocytes. Although GLUT4 expression is preserved in muscle, these mice develop insulin resistance in muscle and liver, manifested by decreased biological responses and impaired activation of phosphoinositide-3-OH kinase. G4A-/- mice develop glucose intolerance and hyperinsulinaemia. Thus, downregulation of GLUT4 and glucose transport selectively in adipose tissue can cause insulin resistance and thereby increase the risk of developing diabetes.

Natural occurrence of aflatoxins in Korean meju

Aflatoxin B1 (AFB1) was found in 35 of 60 (58.3%) meju samples with an average concentration of 7.3 ng/g by ELISA. Contamination of AFB1 was confirmed in 25 of 60 samples (41.6%) using HPLC, with an average concentration of 6.9 ng/g. Mean recoveries from meju ranged from 107% to 170% for AFB1 using ELISA at a spiking range of 1 to 50 ng/g. Over the same range, recoveries using HPLC were from 70% to 83%. The levels of AFB1 determined by ELISA and by HPLC demonstrated a close relationship between the two methods (r2 = 0.9324) employed in this study. In order to evaluate the potential health risks of AFB1 on Koreans consuming meju, we calculated the estimated probable daily intake (PDI) based on the average contamination levels and compared it with the estimated tolerable daily intake (TDI). The PDIs of AFB1 from kanjang and dwenjang were determined to be 0.04 and 0.21 ng/kg bw/day, respectively, and were higher than TDIs.

Increased proliferation activities of vascular endothelial cells and tumour cells in residual hepatocellular carcinoma following transcatheter arterial embolization

AIMS

Transcatheter arterial embolization induces extensive ischaemic necrosis or hypoxia via the obstruction of the hepatic artery in hepatocellular carcinoma (HCC). Ischaemia is strongly correlated with an increased expression of angiogenic factor and stimulates an increase in angiogenesis, including endothelial cell proliferation. The aim of this study was to evaluate whether ischaemic necrosis induced by transcatheter arterial embolization could increase the proliferative activities of intratumoral endothelial cells or tumour cells in the residual HCC.

METHODS AND RESULTS

Using a double immunohistochemical technique (Ki67 antibody to determine the proliferative activity and CD34 antibody to highlight the intratumoral endothelial cells), we performed immunohistochemical staining for 24 HCCs treated by transcatheter arterial embolization. Seven HCCs without any preoperative transcatheter arterial embolization and nine cirrhosis cases were also studied as the control cases. The residual tumour was then divided into five areas at 0.5 mm intervals, according to the distance from the necrotic margin induced by embolization. The Ki67 labelling indices of the intratumoral endothelial cells and tumour cells were counted in each area. The correlation between the indices and the corresponding distance from the ischaemic necrosis was analysed. The Ki67 labelling index of intratumoral vascular endothelial cells in the area less than 0.5 mm from the necrotic margin (area 1) was 10.60 +/- 3.64% (mean +/- SD), which was twofold greater than those of the other areas more than 0.5 mm from the margin (areas 2--5) and those of the control HCCs without preoperative transcatheter arterial embolization. In addition, the proliferation labelling index of the tumour cells was 35.77 +/- 11.45% (mean +/- SD) in area 1. This was higher than those of areas 2--5 and control HCCs without preoperative transcatheter arterial embolization. There was a positive correlation between the proliferation of both endothelial and tumour cells and ischaemic necrosis (P < 0.05).

CONCLUSIONS

Our study suggests that the proliferative activity of intratumoral endothelial cells and tumour cells is increased by ischaemic necrosis induced by transcatheter arterial embolization, and its effect is maximal in the area adjacent to the necrosis (less than 0.5 mm from the necrotic margin).

Hyperfractionated re-irradiation using a 3-dimensional conformal technique for locally recurrent carcinoma of the nasopharynx; preliminary results

To evaluate the efficacy of hyperfractionated re-irradiation using a three-dimensional conformal radiotherapy (3-D CRT) technique in patients with locally recurrent carcinoma of the nasopharynx. Four patients with locally recurrent nasopharyngeal cancer were retreated with a hyperfractionated schedule using a 3-D CRT technique. Re-irradiation was delivered in 1.1-1.2 Gy fractions twice per day (BID), with interfraction intervals of more than 6 hours. The total dose ranged from 59.4 to 69.2 Gy. A 3-D CRT technique with 5- or 6-field coplanar and/or non-coplanar beams were employed during the entire treatment procedure. All four patients achieved complete remission of locally recurrent lesions, with marked improvement of subjective symptoms, immediately after re-irradiation. All are alive and well without evidence of disease after limited follow-up periods, which range from 7 to 20 months. So far, there have been no radiation-induced neurologic complications. Four patients with locally recurrent carcinoma of the nasopharynx were successfully treated by hyperfractionated re-irradiation using a 3-D CRT technique. A relatively high re-irradiation dose of more than 60 Gy may be safely delivered with no serious acute or late radiation-induced complications in patients with local recurrences and who were initially treated with doses greater than 70 Gy.

Overexpression of c-H-ras p21 is correlated with vascular endothelial growth factor expression and neovascularization in advanced gastric carcinoma

BACKGROUND AND AIMS

ras Gene and its product (p21) have been reported to be associated with vascular endothelial growth factor (VEGF), which is one of the most important angiogenic factors, and tumor-associated angiogenesis. We tried to evaluate the correlation between the expression of c-H-ras gene product p21 and angiogenesis in advanced gastric carcinoma.

METHODS

Immunohistochemical expression of c-H-ras p21 and VEGF was examined in 49 advanced gastric adenocarcinomas. In addition, double immunohistochemical staining was performed using anti-CD34 and anti-Ki-67 antibodies, and the intratumoral microvessel densities and their endothelial proliferative labeling indices were then counted to evaluate the degree of angiogenesis.

RESULTS

The expression of c-H-ras p21 was demonstrated in 43 out of 49 gastric adenocarcinomas (87.8%). It did not correlate with histologic type, depth of invasion or metastasis. However, the degree of c-H-ras p21 expression was correlated with VEGF. In addition, the degree of c-H-ras p21 expression was correlated with increased intratumoral microvascular density and endothelial proliferative activity.

CONCLUSIONS

We suggest that c-H-ras oncogene product p21 contributes to the upregulation of tumor-associated angiogenesis by the increased production of VEGF in advanced gastric carcinomas. Therefore, treatment involving the targeting of ras oncogene could inhibit solid tumor growth by suppressing tumor-associated angiogenesis.

Evaluation of various carbon substrates for the biosynthesis of polyhydroxyalkanoates bearing functional groups by Pseudomonas putida

The ability of Pseudomonas putida to synthesize polyhydroxyalkanoate (PHA) from 36 different carboxylic acids containing various functional groups was examined. This bacterium did not utilize short carboxylic acids (C(4)-C(6)) containing bromine, methoxy, ethoxy, cyclohexyl, phenoxy, and olefin groups as the sole carbon substrate. No polymer was isolated from the cells grown with carboxylic acids bearing hydroxyl, amino, para-methoxyphenoxy, and para-ethoxyphenoxy groups regardless of the carbon substrate chain lengths used even when they were cofed with nonanoic acid. Of all the carbon substrates evaluated, only 6-para-methylphenoxyhexanoic acid, 8-para-methylphenoxyoctanoic acid, 8-meta-methylphenoxyoctanoic acid, 10-undecenoic acid, and 10-undecynoic acid supported both growth and the production of PHA containing the corresponding functional groups by P. putida. The present results indicate that the carbon availability of P. putida for growth and PHA production is significantly different from that of P. oleovorans.

CM1, a possible novel activation molecule on human lymphocytes

CM1 (centrocyte/-blast marker 1) defined by a mAb developed against concanavalin-A activated PBMC, is expressed specifically on some tonsillar germinal center (GC) B cells. In single flow cytometric analysis, the bone marrow did not express these molecules nor did the PBMC or the thymocytes. The peripheral B lymphocytes showed more than 90% positive, while the peripheral T lymphocytes showed approximately 60% positive at 48 h after activation by PMA/ionomycin, respectively. A western blot analysis and an immunoprecipitation for CM1 showed a band at 70 kDa. Cross-linking of CM1 with anti-CM1 mAb induced apoptosis of the GC B cells (CD38(+)IgD(-)). Immunohistochemical staining revealed that the CM1 molecule is distributed over the entire area except the proximal dark zone of the tonsillar germinal centers. These results suggest that the CM1 molecule might be involved in differentiation of the germinal center B cells as one of the novel centrocyte markers.

Metastatic renal cell carcinoma in a meningioma: a case report

Tumor-to-tumor metastasis is rare. We report a case of metastatic renal cell carcinoma in meningioma. A 67-year-old woman presented a two-week history of motor dysphagia and decreased short-term memory. She had undergone a left radical nephrectomy for a renal cell carcinoma 7 years ago, and had not received any adjuvant therapy. MRI disclosed a 3.0 x 3.0 x 3.0-cm sized round tentorial-based extraaxial mass with peritumoral edema in the left posterior temporal lobe. During operation, the tumor was found to be an encapsulated mass firmly attached to the tentorium. Histologically, the tumor was a meningotheliomatous meningioma extensively infiltrated by metastatic renal cell carcinoma, accompanying widespread coagulative necrosis. Immunohistochemical staining for cytokeratin revealed strong positivity only in the renal cell carcinoma component. The patient's postoperative course was uneventful. Post-operative radiation therapy was applied to the whole brain. Three months after operation, the patient developed right hemiparesis and dysphagia. Brain MRI at that time did not reveal recurrence or any other causative lesions, although the whole body scan disclosed uptake at the second lumbar vertebra and rib. The patient refused further treatment.

Mechanism of cell cycle arrest caused by histone deacetylase inhibitors in human carcinoma cells

Inhibitors of histone deacetylase (HDAC) block cell cycle progression at G1 in many cell types. We investigated the mechanism by which trichostatin A (TSA), a specific inhibitor of HDAC, induces G1 arrest in human cervix carcinoma HeLa cells. TSA treatment induced histone hyperacetylation followed by growth arrest in G as well as hypophosphorylation of pRb. The Cdk4 kinase activity was essentially unchanged during the TSA-induced G1 arrest. On the other hand, the arrest was accompanied by down-regulation of kinase activity of Cdk2, although the total protein levels of Cdk2 and its activator Cdc25A were unaffected. Upon TSA treatment, amounts of cyclin E and the CDK inhibitor p21WAF1/Cip1 were markedly increased, while that of cyclin A was reduced. The induction of p21 and down-regulation of cyclin A correlated well with the decreased Cdk2 activity and cell cycle arrest. Furthermore, gel filtration chromatography showed the association of p21 with the cyclin E-Cdk2 complex, suggesting that the activation of Cdk2 by the enhanced expression of cyclin E is blocked by the increased p21. The elevated expression of p2 is also observed in cells treated with trapoxin and FR901228, structurally unrelated histone deacetylase inhibitors. A human colorectal carcinoma cell line lacking both alleles of the p21 gene (p21-/-) was resistant to TSA several times more than the parental line (p21+/+). These results suggest that the suppression of Cdk2 kinase activity due to p21 overexpression play a critical role in HDAC inhibitor-induced growth inhibition.

Churg-Strauss syndrome with perforating ulcers of the colon

We report a case of a 72-year-old woman with Churg-Strauss syndrome, who presented with intestinal perforation. She has had bronchial asthma with peripheral blood eosinophilia for 30 years. Gross findings of a resected colon showed multiple ulcers with perforation. Histologic findings demonstrated transmural inflammation infiltrated with large numbers of eosionophils, neutrophils and lymphoplasma cells, and characteristic extravascular granuloma in the subserosa. There were multifocally-distributed transmural vasculitis showing all stages of activity in medium and small-sized arteries and veins located in the submucosa, and proper muscle and subserosal layers of the colon, some of which revealed granulomatous inflammation. Histologic finding of liver showed chronic viral hepatitis B with mild inflammatory activity and macronodular cirrhosis. Immunohistochemical findings, acid fuschin orange G staining and electromicroscope found no evidence of hepatitis B virus infection contributing to the pathogenesis of this lesion.

A case of primary hepatic lymphoma with hepatitis C liver cirrhosis

Primary hepatic lymphoma is rare. The usual type is a large-cell, high-grade malignant B-cell lymphoma, although T-cell types have been described. Several cases of primary hepatic lymphoma of B-cell origin developing in patients with chronic hepatitis C virus infection have been reported. Recently, new findings have raised the question of the induction of lymphoma by hepatitis C virus. However, the causal relationship between hepatitis C viral infection and primary hepatic lymphoma remains obscure. This article reports a case of histologically proven primary hepatic lymphoma of T-cell origin, which was confined to the liver, in the setting of hepatitis C liver cirrhosis. This association has not previously been reported.

Increased expression of vascular endothelial growth factor and angiogenesis in the early stage of multistep hepatocarcinogenesis

BACKGROUND

Hepatocellular carcinoma (HCC) is known to receive its blood supply principally from the hepatic arteries. Recent studies have reported differences in the vascular supply, especially arterial supply among low- and high-grade dysplastic nodules (DNs) (also referred to as adenomatous hyperplasia and macroregenerative nodules) and HCCs. Increased expression of vascular endothelial growth factor (VEGF) has been reported in HCC. In addition, VEGF may play an important role in the early phases of hepatocarcinogenesis.

METHODS

We immunohistochemically stained 7 low-grade DNs, 8 high-grade DNs, 11 early HCCs, 17 small HCCs, and 21 advanced HCCs with antibodies against VEGF, alpha-smooth muscle actin (to identify unpaired arteries, ie, arteries not accompanied by bile ducts, indicative of angiogenesis), CD34 (as a marker of sinusoidal capillarization), and proliferation cell nuclear antigen.

RESULTS

Expression of VEGF was found in the hepatocytes and HCC cells. The degree of VEGF expression increased gradually according to the stepwise development of hepatocarcinogenesis. It was higher in high-grade DNs and early HCCs than in low-grade DNs. The hepatocytes and HCC cells adjacent to peliosis and fibrous septa showed stronger VEGF expression. Angiogenesis, unpaired arteries, and sinusoidal capillarization developed from low-grade DNs and gradually increased. It was highest in HCCs. The proliferation cell nuclear antigen labeling indexes of hepatocytes and HCC cells also increased gradually as hepatocarcinogenesis progressed. Small HCCs showed a higher status of neoangiogenesis and cell proliferation activity than advanced HCCs. The degree of VEGF expression was correlated with angiogenesis and cell proliferation activity.

CONCLUSION

We conclude that VEGF plays a significant role in angiogenesis, growth, and development of HCC.

Increased expression of vascular endothelial growth factor and angiogenesis in the early stage of multistep hepatocarcinogenesis

BACKGROUND

Hepatocellular carcinoma (HCC) is known to receive its blood supply principally from the hepatic arteries. Recent studies have reported differences in the vascular supply, especially arterial supply among low- and high-grade dysplastic nodules (DNs) (also referred to as adenomatous hyperplasia and macroregenerative nodules) and HCCs. Increased expression of vascular endothelial growth factor (VEGF) has been reported in HCC. In addition, VEGF may play an important role in the early phases of hepatocarcinogenesis.

METHODS

We immunohistochemically stained 7 low-grade DNs, 8 high-grade DNs, 11 early HCCs, 17 small HCCs, and 21 advanced HCCs with antibodies against VEGF, alpha-smooth muscle actin (to identify unpaired arteries, ie, arteries not accompanied by bile ducts, indicative of angiogenesis), CD34 (as a marker of sinusoidal capillarization), and proliferation cell nuclear antigen.

RESULTS

Expression of VEGF was found in the hepatocytes and HCC cells. The degree of VEGF expression increased gradually according to the stepwise development of hepatocarcinogenesis. It was higher in high-grade DNs and early HCCs than in low-grade DNs. The hepatocytes and HCC cells adjacent to peliosis and fibrous septa showed stronger VEGF expression. Angiogenesis, unpaired arteries, and sinusoidal capillarization developed from low-grade DNs and gradually increased. It was highest in HCCs. The proliferation cell nuclear antigen labeling indexes of hepatocytes and HCC cells also increased gradually as hepatocarcinogenesis progressed. Small HCCs showed a higher status of neoangiogenesis and cell proliferation activity than advanced HCCs. The degree of VEGF expression was correlated with angiogenesis and cell proliferation activity.

CONCLUSION

We conclude that VEGF plays a significant role in angiogenesis, growth, and development of HCC.

Increased energy expenditure, decreased adiposity, and tissue-specific insulin sensitivity in protein-tyrosine phosphatase 1B-deficient mice

Protein-tyrosine phosphatase 1B (PTP-1B) is a major protein-tyrosine phosphatase that has been implicated in the regulation of insulin action, as well as in other signal transduction pathways. To investigate the role of PTP-1B in vivo, we generated homozygotic PTP-1B-null mice by targeted gene disruption. PTP-1B-deficient mice have remarkably low adiposity and are protected from diet-induced obesity. Decreased adiposity is due to a marked reduction in fat cell mass without a decrease in adipocyte number. Leanness in PTP-1B-deficient mice is accompanied by increased basal metabolic rate and total energy expenditure, without marked alteration of uncoupling protein mRNA expression. In addition, insulin-stimulated whole-body glucose disposal is enhanced significantly in PTP-1B-deficient animals, as shown by hyperinsulinemic-euglycemic clamp studies. Remarkably, increased insulin sensitivity in PTP-1B-deficient mice is tissue specific, as insulin-stimulated glucose uptake is elevated in skeletal muscle, whereas adipose tissue is unaffected. Our results identify PTP-1B as a major regulator of energy balance, insulin sensitivity, and body fat stores in vivo.

Diheteropeptin, a new substance with TGF-beta-like activity, produced by a fungus, Diheterospora chlamydosporia. I. Production, isolation and biological activities

A new metabolite, diheteropeptin, was found in the culture broth of Diheterospora chlamydosporia Q58044 by screening for TGF-beta-like active substances. Diheteropeptin was extracted from the culture supernatant and purified by a series of chromatographies such as silica gel, gel filtration and HPLC. Diheteropeptin exhibited cytostatic activity in Mv1Lu cells with an IC50 value of 20.3 microM and inhibited histone deacetylase.

Increased expression of vascular endothelial growth factor and angiogenesis in the early stage of multistep hepatocarcinogenesis

BACKGROUND

Hepatocellular carcinoma (HCC) is known to receive its blood supply principally from the hepatic arteries. Recent studies have reported differences in the vascular supply, especially arterial supply among low- and high-grade dysplastic nodules (DNs) (also referred to as adenomatous hyperplasia and macroregenerative nodules) and HCCs. Increased expression of vascular endothelial growth factor (VEGF) has been reported in HCC. In addition, VEGF may play an important role in the early phases of hepatocarcinogenesis.

METHODS

We immunohistochemically stained 7 low-grade DNs, 8 high-grade DNs, 11 early HCCs, 17 small HCCs, and 21 advanced HCCs with antibodies against VEGF, alpha-smooth muscle actin (to identify unpaired arteries, ie, arteries not accompanied by bile ducts, indicative of angiogenesis), CD34 (as a marker of sinusoidal capillarization), and proliferation cell nuclear antigen.

RESULTS

Expression of VEGF was found in the hepatocytes and HCC cells. The degree of VEGF expression increased gradually according to the stepwise development of hepatocarcinogenesis. It was higher in high-grade DNs and early HCCs than in low-grade DNs. The hepatocytes and HCC cells adjacent to peliosis and fibrous septa showed stronger VEGF expression. Angiogenesis, unpaired arteries, and sinusoidal capillarization developed from low-grade DNs and gradually increased. It was highest in HCCs. The proliferation cell nuclear antigen labeling indexes of hepatocytes and HCC cells also increased gradually as hepatocarcinogenesis progressed. Small HCCs showed a higher status of neoangiogenesis and cell proliferation activity than advanced HCCs. The degree of VEGF expression was correlated with angiogenesis and cell proliferation activity.

CONCLUSION

We conclude that VEGF plays a significant role in angiogenesis, growth, and development of HCC.

Usefulness of triphasic perfusion computed tomography for intravenous thrombolysis with tissue-type plasminogen activator in acute ischemic stroke

BACKGROUND

Intravenous thrombolysis for acute ischemic stroke has been investigated in several clinical trials without enough information on collateral blood flow and perfusion deficit in the ischemic areas. The therapeutic time window varies from patient to patient depending on these factors. Triphasic perfusion computed tomography (TPCT) can provide this information as reliably as conventional angiography.

OBJECTIVE

To assess the safety and efficacy of thrombolysis within 3 or 7 hours of stroke onset according to the extent of perfusion deficit on TPCT.

METHODS

In 46 patients with acute middle cerebral artery (MCA) territory stroke, TPCT was performed with power injector-controlled, intravenous administration of contrast media after taking precontrast CT scans. Sequential scans of early, middle, and late phases were performed. The entire procedure took 5 minutes. Depending on collateral blood flow, the perfusion deficit on TPCT was graded as "severe perfusion deficit" or "moderate perfusion deficit." Twenty-nine patients were excluded based on clinical, laboratory, and TPCT findings. Seventeen patients were treated with an intravenous recombinant tissue-type plasminogen activator, 0.9 mg/kg. The 17 treated patients were divided into 2 groups: group 1 with small severe perfusion deficit (</=33% of the presumed MCA territory) and group 2 with medium-sized severe perfusion deficit (>33% but </=50% of the presumed MCA territory). The 13 patients in group 1 were treated within 7 hours of onset and the 4 patients in group 2 were treated within 3 hours.

RESULTS

Initial mean National Institutes of Health Stroke Scale score was 12.1 (range, 6.0-20.0) in group 1 and 19.0 (range, 18.0-21. 0) in group 2. The initial score correlated better with the total extent of moderate perfusion deficit and severe perfusion deficit than that of severe perfusion deficit alone. Mean time lapse to thrombolysis was 4.2 hours (range, 1.5-7.0 hours) in group 1 and 2.2 hours (range, 1.9-2.5 hours) in group 2. Eight patients (47%), 7 from group 1 and 1 from group 2, improved by 4 points or more from baseline Stroke Scale score within 24 hours of thrombolysis. Patients with moderate perfusion deficit of 50% or more of MCA territory (n = 4) had a better chance of early improvement than did those (n = 13) with moderate perfusion deficit of less than 50% (4 of 4 vs 4 of 13). No fatal hemorrhage occurred. Only 1 patient (6%) had symptomatic small basal ganglia hemorrhage after thrombolysis.

CONCLUSIONS

Thrombolysis can be safely performed within 3 or 7 hours of stroke onset according to the extent of severe perfusion deficit on TPCT. A larger extent of moderate perfusion deficit on TPCT may predict early improvement after thrombolysis.

A comparison of different lead biomarkers in their associations with lead-related symptoms

OBJECTIVES

To evaluate whether dimercaptosuccinic acid (DMSA) -chelatable lead, an estimate of current bioavailable lead stores, is a better predictor of lead-related symptoms than are other commonly used lead biomarkers.

METHODS

A total of 95 male lead workers from three lead industries (one secondary lead smelting facility, one polyvinyl chloridestabilizer manufacturing plant, and one lead-acid storage battery factory), and 13 workers without occupational lead exposure recruited from an occupational health institute, were studied. Blood lead, blood zinc protoporphyrin (ZPP), 4 h DMSA-chelatable lead (after oral administration of 10 mg/kg DMSA), urine lead, and urinary delta-aminolevulinic acid levels were evaluated as predictors of 15 lead-related symptoms, assessed by self-administered questionnaire, with linear and logistic regression controlling for covariates. Total symptoms and symptoms in three categories (gastrointestinal, neuromuscular, and general) were evaluated.

RESULTS

The mean (SD) 4 h DMSA-chelatable lead level was 288.7 (167.7) microg, with a range from 32.4 to 789 microg in the 95 lead workers. The mean (SD) in the non-exposed subjects was 23.7 (11.5) microg with a range from 10.5 to 43.5 microg. Blood lead, blood ZPP, and spot urine lead levels ranged from 21.4 to 78.4 microg/dl, 40 to 331 microg/l, and 7.5 to 153.0 micro/l, respectively, in the lead workers, and from 4.0 to 7.2 micro/dl, 27 to 52 microg/l, and 2.9 to 15.5 microg/l in the non-exposed controls, respectively. The overall mean symptom score (SD), derived as the sum of 0 or 1 point for absence or presence of 15 symptoms, of the lead workers was 3.7 (2.0), compared to 1.2 (1.5) for the non-exposed workers. DMSA-chelatable lead was the best predictor of symptom scores in both crude and adjusted analyses, compared with the other biomarkers. Lead workers with DMSA-chelatable lead values greater than the median (260.5 microg) were 6.2 times more likely to have frequent tingling or numbness of the arms or legs and 3.3 times more likely to have muscle pain than subjects with lower chelatable lead values. Three symptoms (tingling or numbness of arm or leg, muscle pain, and feeling irritation at the slightest disturbance) evidenced a dose-dependent relationship with DMSA-chelatable lead levels.

CONCLUSIONS

DMSA-chelatable lead was found to be the best predictor of lead-related symptoms, particularly of both total symptom scores and neuromuscular symptoms, than were the other other lead biomarkers.

In vivo administration of leptin activates signal transduction directly in insulin-sensitive tissues: overlapping but distinct pathways from insulin

To determine whether leptin signal transduction is exerted directly upon insulin-sensitive tissues in vivo, we examined the ability of iv leptin to acutely stimulate phosphorylation of STAT3, STAT1, and MAPK, and activities of PI 3-kinase and Akt, in insulin-sensitive tissues of normal rats. Both leptin (1 mg/kg iv x 3 min) and insulin (10 U/kg iv x 3 min) stimulated tyrosine phosphorylation of STAT3 5.6- to 6.0-fold and of STAT1 4.0-fold in adipose tissue. Leptin tended to increase STAT3 phosphorylation in liver and muscle. Both hormones also increased MAPK phosphorylation: leptin increased it 3.2- to 3.8-fold in adipose tissue and liver, whereas insulin stimulated MAPK phosphorylation 5.0-fold in adipose tissue, 6.8-fold in liver, and 2.5-fold in muscle. Leptin was much less effective than insulin at stimulating IRS pathways. Leptin increased IRS-1-associated PI 3-kinase activity in adipose tissue only 2.0-fold (P < 0.01) compared with the 10-fold effect of insulin. IRS-2-associated PI 3-kinase activity was increased 1.7-fold (P < 0.01) by leptin in liver and 6-fold by insulin. Akt phosphorylation and activity were not changed by leptin but increased with insulin. Lower concentrations of leptin (10 and 50 microg/kg) also stimulated STAT3 phosphorylation in fat. These effects appear to be direct because 3 min after leptin intracerebroventricular injection, phosphorylation of STAT3, STAT1, and MAPK were not stimulated in hypothalamus or adipose tissue. Furthermore, leptin activated STAT3 and MAPK in adipose tissue explants ex vivo and in 3T3-L1 adipocytes. Leptin did not activate STAT3 or MAPK in adipose tissue of db/db mice. Thus, leptin rapidly activates signaling pathways directly at the level of insulin sensitive tissues through the long-form leptin receptor, and these pathways overlap with, but are distinct from, those engaged by insulin.

Overexpression of protein-tyrosine phosphatase-1B in adipocytes inhibits insulin-stimulated phosphoinositide 3-kinase activity without altering glucose transport or Akt/Protein kinase B activation

Previous studies suggested that protein-tyrosine phosphatase 1B (PTP1B) antagonizes insulin action by catalyzing dephosphorylation of the insulin receptor (IR) and/or other key proteins in the insulin signaling pathway. In adipose tissue and muscle of obese humans and rodents, PTP1B expression is increased, which led to the hypothesis that PTP1B plays a role in the pathogenesis of insulin resistance. Consistent with this, mice in which the PTP1B gene was disrupted exhibit increased insulin sensitivity. To test whether increased expression of PTP1B in an insulin-sensitive cell type could contribute to insulin resistance, we overexpressed wild-type PTP1B in 3T3L1 adipocytes using adenovirus-mediated gene delivery. PTP1B expression was increased approximately 3-5-fold above endogenous levels at 16 h, approximately 14-fold at 40 h, and approximately 20-fold at 72 h post-transduction. Total protein-tyrosine phosphatase activity was increased by 50% at 16 h, 3-4-fold at 40 h, and 5-6-fold at 72 h post-transduction. Compared with control cells, cells expressing high levels of PTP1B showed a 50-60% decrease in maximally insulin-stimulated tyrosyl phosphorylation of IR and insulin receptor substrate-1 (IRS-1) and phosphoinositide 3-kinase (PI3K) activity associated with IRS-1 or with phosphotyrosine. Akt phosphorylation and activity were unchanged. Phosphorylation of p42 and p44 MAP kinase (MAPK) was reduced approximately 32%. Overexpression of PTP1B had no effect on basal, submaximally or maximally (100 nm) insulin-stimulated glucose transport or on the EC(50) for transport. Our results suggest that: 1) insulin stimulation of glucose transport in adipocytes requires </=45% of maximal tyrosyl phosphorylation of IR or IRS-1 and <50% of maximal activation of PI3K, 2) a novel PI3K-independent pathway may play a role in insulin-induced glucose transport in adipocytes, and 3) overexpression of PTP1B alone in adipocytes does not impair glucose transport.

Endogenous interleukin-18 modulates immune escape of murine melanoma cells by regulating the expression of Fas ligand and reactive oxygen intermediates

It has been known that melanoma cells can suppress the immune system by the Fas ligand. The present study investigated whether interleukin (IL)-18, which can enhance Fas ligand expression, is produced by B16F10 melanoma cells and is involved in immune escape of tumor cells. Immunohistology, reverse transcription-PCR, intracellular fluorescence-activated cell-sorting analysis, and immunoblotting demonstrated that melanoma cells express IL-18. C57BL/6 splenocytes cultured with culture supernatants of B16F10 melanoma cells enhanced IFN-gamma production, which was blocked by anti-IL-18 antibody, indicating that IL-18 in the culture supernatants is functional. In addition to IL-18, the IL-18 receptor was also detected in B16F10 melanoma cells, suggesting a role of this cytokine in regulating the functions of B16F10 melanoma cells. The functional effect of IL-18 on B16F10 melanoma cells was shown by reduction of Fas ligand expression in cells treated with anti-IL-18 antibody or transfected with IL-18 antisense cDNA. In addition, the same treatments decreased intracellular reactive oxygen intermediate levels in B16F10 melanoma cells, indicating that IL-18 regulates reactive oxygen intermediate production, which is involved in Fas ligand expression. Furthermore, transfection of IL-18 antisense cDNA into melanoma cells increased the susceptibility of tumor cells to natural killer cells in vitro. When IL-18 antisense transfectants were implanted into syngeneic mice, severe reduction of tumor cell growth was observed with concomitant infiltrated natural killer cells in the tumor area. Taken together, these results demonstrate that IL-18 has a critical role as a survival factor for B16F10 melanoma cells.

Ciliated foregut cyst of the gallbladder: a case report and review of the literature

A case is presented of a ciliated cyst of the gallbladder in a 36-year-old Korean woman which was incidentally found on ultrasonographic study. A cystic mass measuring 1.5 x 1 x 1 cm was found in the fundus of the gallbladder. The cyst was unilocular and intramural without communication to the lumen. Microscopically, the cyst wall was lined by a single layer of pseudostratified, ciliated, columnar epithelium and goblet cells with underlying smooth muscle layers. This was considered to be the cyst arising from the embryonic foregut and showing differentiation toward respiratory structures. The term 'ciliated foregut cyst of the gallbladder' is suggested here.