Interaction of PRK1 receptor-like kinase with a putative elF2B beta-subunit in tobacco

PRK1, a receptor-like kinase that is expressed in pollen, pollen tubes, and ovaries, has been shown to play important roles in pollen development and embryo sac development in Petunia inflata. We have used the kinase domain of PRK1 as a bait in the yeast two-hybrid system to identify PRK1-interacting proteins. The screening resulted in isolation of a cDNA encoding a protein highly homologous to the human and yeast beta-subunit of translation initiation factor 2B (eIF2B-beta), which was designated NeIF2Bbeta. eIF2B is a guanine nucleotide exchange protein that functions in the regulation of translation in eukaryotic cells. Deletion mutants of NeIF2Bbeta were analyzed for their interaction with PRK1, and the results suggested that the N-terminal half of NeIF2Bbeta, especially the region between residue 103 and 235, is important for the interaction. This protein association was confirmed by in vitro binding assay of the recombinant NeIF2Bbeta and PRK1 proteins. Despite high sequence homology between NeIF2Bbeta and its yeast counterpart, the NeIF2Bbeta cDNA could not rescue the phenotype of the yeast mutant strain lacking the GCD7 gene encoding eIF2B-beta, when transferred into the mutant strain.

Synthesis and biological activity of 1beta-methyl-2-[5'-isoxazoloethenylpyrrolidin-3'-ylthio]carbapenems

A new series of 1beta-methylcarbapenems 1a-i bearing isoxazoloethenyl groups on the pyrrolidine ring has been prepared and evaluated for in vitro antibacterial activity and stability to DHP-I. Most compounds showed excellent antibacterial activity and high stability to DHP-I superior to that of meropenem. Of these new carbapenems, 1a,b,h exhibited the best combination of antibacterial activity and DHP-I stability.

Determinants of coronary blood flow following primary angioplasty for acute myocardial infarction

The aim of this study was to evaluate determinants of coronary blood flow following primary angioplasty (PA) in acute myocardial infarction (AMI). The corrected TIMI (thrombolysis in myocardial infarction) frame count and the TIMI flow grade were used as indexes of coronary blood flow, and its determinants were examined in 115 consecutive AMI patients who underwent PA (pain onset </= 12 hr). The following were validated as univariate predictors of slower corrected TIMI frame count: a lower pressure-derived farctional collateral flow (PDCF) index (P < 0.01), poor angiographic collaterals (P < 0.01), TIMI flow 0, 1 before PA (P < 0.05), and the presence of heavy thrombi (P < 0.01). The PDCF index and the presence of heavy thrombi were independent predictors of the corrected TIMI frame count. Likewise, the PDCF index (chi(2) = 12.9; P < 0.01) and the presence of heavy thombi (chi(2) = 11.4; P < 0.01) were independent predictors of TIMI 3 flow. In conclusion, collateral flow and the presence of thrombi are major determinants of coronary blood flow after PA in AMI.

Effects of beta-toxin of Staphylococcus aureus on ciliary activity of nasal epithelial cells

OBJECTIVES

To investigate the in vitro effects of staphylococcal beta-toxin on ciliary activity and the in vivo effects on sinusitis induction.

STUDY DESIGN

The in vitro effects of staphylococcal beta-toxin on ciliary activity were investigated at different concentrations and exposure times. Experimental sinusitis was induced in rabbits with application of beta-toxin and confirmed 7 days later.

METHODS

Ciliated epithelial cells were taken from the maxillary sinus mucosa of 10 rabbits. Five culture dishes from each rabbit were used for the experimental group, and one culture dish from each rabbit was used for the control group. In the experimental group, ciliary beat frequency (CBF) was measured at concentrations of 0.1, 1, 2, 5 and 10 U/mL of beta-toxin using a video-computerized analysis technique, while in the control group, culture medium containing no toxin was used. CBF was measured 1, 2, 4, 6, 8, 12, 24, and 48 hours after administration of beta-toxin. To induce experimental sinusitis, 2 U/mL of beta-toxin was percutaneously applied to the maxillary sinus of 10 rabbits without occlusion of the natural ostium, while normal saline was percutaneously applied to the right-side maxillary sinus of 4 rabbits in the control group. At 7 days, mucosal membranes were taken from the inferomedial wall of the maxillary sinus for light microscopic study.

RESULTS

CBF dropped significantly after an 8-hour incubation at 2, 5, and 10 U/mL of beta-toxin. No ciliary activity was observed after a 24-hour incubation at 2 and 5 U/mL and a 12-hour incubation at 10 U/mL of beta-toxin. Mucoid, purulent discharge was observed in the maxillary sinuses of the beta-toxin-applied group. Prominent epithelial disruption and infiltration of inflammatory cells into the epithelium and lamina propria were observed in the beta-toxin-applied group.

CONCLUSIONS

Staphylococcal beta-toxin may reduce ciliary activity and induce sinusitis without occlusion of the natural ostium of the maxillary sinus in rabbits This study provides another animal model of sinusitis for understanding the pathogenesis of sinusitis induced by bacterial exotoxins.

MR imaging of changes of the growth plate after partial physeal removal and fat graft interposition in rabbits

RATIONALE AND OBJECTIVES

The most important complication of skeletal injuries involving the growth plate is growth disturbance. The purpose of this study was to evaluate MR features of growth plate modification after fat graft interposition in growth plate injury and to correlate these findings with pathological findings.

METHODS

A growth plate injury model was used in 12 skeletally immature rabbits. A longitudinal drill hole 5 mm in diameter was created in the central part of the growth plate in the distal femur, bilaterally. One side was filled with autologous fat, and the contralateral defect was left empty as a control. Magnetic resonance imaging was obtained 1, 3, and 6 months after surgery, and routine histological study was performed. The authors evaluated sequential changes in MR images and the histological basis of MR findings.

RESULTS

In grafted femur, the signal intensity of the grafted area was lower than that of the surrounding bone on T2-weighted images at 1 month. The growth plate defect at 3 to 6 months was modified and had a proximally tapering appearance. The ratio of the growth plate defect was smaller in the grafted femur than in the control femur after surgery. Histologically, the fat-grafted area was replaced by fibrous connective tissue. In the control femur, a bony bridge was rectangular in the longitudinal direction and showed isosignal intensity with a rim of low signal intensity on T1-weighted imaging. Histologically, the defect was filled with mature fatty marrow with new bone formation in the control femur.

CONCLUSIONS

The proximally pointing appearance and the low signal intensity of the grafted area on MR suggested fibrous degeneration of grafted fat that prevented solid bony bridge formation in experimentally induced growth plate injury.

Randomized comparison of coronary stenting with optimal balloon angioplasty for treatment of lesions in small coronary arteries

AIMS

Angioplasty of lesions in small coronary arteries remains a significant problem because of the increased risk of restenosis. The aim of this study was to compare the efficacy of elective coronary stent placement and optimal balloon angioplasty in small vessel disease.

METHODS

One hundred and twenty patients with lesions in small coronary arteries (de novo, non-ostial lesion and reference diameter <3 mm) were randomly assigned to either balloon angioplasty or elective stent placement (7-cell NIR stent). The primary end-point was restenosis at 6 months follow-up. Optimal balloon angioplasty was defined as diameter stenosis less than or = 30% and the absence of major dissection after the angioplasty, and crossover to stenting was allowed.

RESULTS

Baseline clinical and angiographic characteristics were similar in the two groups. Procedure was successful in all patients, and in-hospital events did not occur in any patient. However, 12 patients in the angioplasty group were stented because of suboptimal results or major dissection. Postprocedural lumen diameter was significantly larger in the stent group than in the angioplasty group (2.44 +/- 0.36 mm vs 2.14 +/- 0.36, P<0.05, respectively), but late loss was greater in the stent group (1.12 +/- 0.67 mm vs 0.63 +/- 0.48, P<0.01, respectively). The angiographic restenosis rate was 30.9% in the angioplasty group, and 35.7% in the stent group (P = ns). Clinical follow-up was available in all patients (15.9 +/- 5.7 months) and clinical events during the follow-up were similar in both groups.

CONCLUSIONS

These results suggest that optimal balloon angioplasty with provisional stenting may be a reasonable approach for treatment of lesions in small coronary arteries.

Long-term outcomes of minor dissection at the edge of stents detected with intravascular ultrasound

We evaluated the influences of minor edge dissections on late angiographic in-stent restenosis in 327 patients with 348 lesions (281 lesions without edge dissection and 67 lesions [19.3%] with edge dissection); the angiographic restenosis rate was 29.9% in the lesions with edge dissections versus 25.3% without edge dissections (p = 0.540). The minor non-flow-limiting dissections at the edge of stents may not be associated with the development of late angiographic in-stent restenosis.

The roles of sterol regulatory element-binding proteins in the transactivation of the rat ATP citrate-lyase promoter

ATP citrate-lyase (ACL) is a key enzyme supplying acetyl-CoA for fatty acid and cholesterol synthesis. Its expression is drastically up-regulated when an animal is fed a low fat, high carbohydrate diet after prolonged fasting. In this report, we describe the role of sterol regulatory element-binding proteins (SREBPs) in the transactivation of the rat ACL promoter. ACL promoter activity was markedly stimulated by the overexpression of SREBP-1a and, to a lesser extent, by SREBP-2 in Alexander human hepatoma cells. The promoter elements responsive to SREBPs were located within the 55-base pair sequences from -114 to -60. The gel mobility shift assay revealed four SREBP-1a binding sites in this region. Of these four elements, the -102/-94 region, immediately upstream of the inverted Y-box, and the -70/-61 region, just adjacent to Sp1 binding site, played critical roles in SREBPs-mediated stimulation. The mutation in the inverted Y-box and the coexpression of dominant negative nuclear factor-Y (NF-Y) significantly attenuated the transactivation by SREBP-1a, suggesting that NF-Y binding is a prerequisite for SREBPs to activate the ACL promoter. However, the multiple Sp1 binding sites did not affect the transactivation of the ACL promoter by SREBPs. The binding affinity of SREBP-1a to SREs of the ACL promoter also was much higher than that of SREBP-2. The transactivation potencies of the chimeric SREBPs, of which the activation domains (70 amino acids of the amino terminus) were derived from the different species of their carboxyl-terminal region, were similar to those of SREBPs corresponding to their carboxyl termini. Therefore, it is suggested that the carboxyl-terminal portions of SREBPs containing DNA binding domains are important in determining their transactivation potencies to a certain promoter.

Effects of cilostazol on angiographic restenosis after coronary stent placement

This study evaluates the impact of cilostazol on post-stenting restenosis. Cilostazol is a potent antiplatelet agent with antiproliferative properties. Few data are available about the effect of cilostazol on poststenting restenosis. Four hundred nine patients (494 lesions) who were scheduled for elective stenting were randomized to receive aspirin plus ticlopidine (group I, n = 201, 240 lesions) or aspirin plus cilostazol (group II, n = 208, 254 lesions), starting 2 days before stenting. Ticlopidine was given for 1 month and cilostazol for 6 months. Follow-up angiography was performed at 6 months, and clinical evaluation at regular intervals. Baseline characteristics were similar between the 2 groups. The procedural success rate was 99.6% in group I and 100% in group II. There were no cases of stent thrombosis after stenting. Angiographic follow-up was performed in 380 of the 494 eligible lesions and the angiographic restenosis rate was 27% in group I and 22.9% in group II (p = NS). However, diffuse type in-stent restenosis was more common in group I than in group II (54.2% vs 26.8%, respectively, p <0.05). In diabetic patients, the angiographic restenosis rate was 50% in group I and 21.7% in group II (p <0.05). Clinical events during follow-up did not differ between the 2 groups. In conclusion, aspirin plus cilostazol seems to be an effective antithrombotic regimen with comparable results to aspirin plus ticlopidine, but it does not reduce the overall angiographic restenosis rate after elective coronary stenting.

Long-term outcomes of minor plaque prolapsed within stents documented with intravascular ultrasound

The direct relationship between minor plaque prolapsed within stents and late in-stent restenosis is unknown. Therefore, we evaluated the impact of minor plaque prolapse on late angiographic in-stent restenosis. Intravascular ultrasonography (IVUS)-guided single-coronary stenting was successfully performed on 384 consecutive patients with 407 native coronary lesions. Six-month follow-up angiographic evaluation was performed on 315 patients (82. 0%) with 334 lesions (82.1%). Minor plaque prolapsed within the stent was found in 75 of 334 lesions (22.5%). Results were evaluated using angiographic and IVUS methods. The development of minor plaque prolapse was significantly associated with infarct-related artery (P = 0.000) and small pre-intervention minimal lumen diameter (P = 0. 001). The overall angiographic restenosis rate was 23.1% (77/334)-21.3% (16/75) in the lesions with plaque prolapse vs. 23.6% (61/259) in the lesions without plaque prolapse (P = 0.806). In conclusion, minor plaque prolapsed within stents might not be associated with late angiographic in-stent restenosis.

Intravascular ultrasound findings of negative arterial remodeling at sites of focal coronary spasm in patients with vasospastic angina

BACKGROUND

There are few data about the intravascular ultrasound (IVUS) findings in patients with vasospastic angina, especially regarding patterns of vascular remodeling.

METHODS AND RESULTS

Coronary spasm was documented by angiography and electrocardiographic evidence of ischemia in 36 patients after administration of ergonovine (cumulative doses up to 350 microg). After relief of spasm with 1000 microg of intracoronary nitroglycerin, quantitative angiography and IVUS imaging were performed and analyzed by standard methods. The 36 focal spasm sites were compared with the proximal and distal reference segments. The angiographic baseline minimum lumen diameter measured 1.78 +/- 0.66 mm, which decreased to 0.66 +/- 0.38 mm with ergonovine provocation (P <.0001), increased to 2.66 +/- 0.64 mm after intracoronary nitroglycerin (P <.0001 compared with baseline and after ergonovine), and did not change after IVUS imaging (2.66 +/- 0.63, P =.9). By IVUS, atherosclerotic lesions were observed at all coronary spasm sites; the mean plaque burden measured 56% at the spasm site and 35% at the reference. Spasm site plaque composition was hypoechoic in 31 and hyperechoic, noncalcific in 5; there was no calcium. The mean eccentricity index (maximum divided by minimum plaque thickness) was 6.7. Positive remodeling (spasm site arterial area greater than proximal reference) was present in 5; intermediate remodeling (proximal reference greater than spasm site greater than distal reference arterial area) was present in 7; and negative remodeling (spasm site arterial area less than distal reference) was present in 24.

CONCLUSIONS

Sites of vasospasm in patients with variant angina showed characteristics of early atherosclerosis, except for an unusually high incidence of negative arterial remodeling.

Side-branch occlusion after rotational atherectomy of in-stent restenosis: incidence, predictors, and clinical significance

We evaluated the incidence, predictors, and clinical significance of side-branch occlusion (SBO) after rotational atherectomy (RA) for treatment of in-stent restenosis (ISR) and compared it with those of native coronary artery (NC). RA was performed in 64 patients with 34 ISR (42 side branches) and 30 NC (40 side branches). SBO occurred 14% after RA in ISR group compared with 0% in NC group (P < 0.05), and 33% after adjunctive balloon inflation in ISR group compared with 2.5% in NC group (P < 0.01). Non-Q myocardial infarction developed in seven patients in ISR group and four patients in NC group (P = NS). The presence of significant side-branch (SB) ostial disease (OR = 4.7, P < 0.05) and ISR lesions (OR = 15.5, P < 0.05) were the only independent predictors of SBO by multivariate analysis. The incidence of SBO is higher after RA of ISR than RA of NC and may be associated with an increased risk of non-Q myocardial infarction.

Synthesis and biological properties of new 1beta-methylcarbapenems having tetrazolothioether moiety

The synthesis and biological activities of a series of new 1beta-methylcarbapenems 1a-l having tetrazolothioether moiety at C-5 position of pyrrolidine were described. Among these compounds, 1c showed the most potent antibacterial activity and advanced pharmacokinetics compared with imipenem and meropenem.

CHRK1, a chitinase-related receptor-like kinase in tobacco

A cDNA encoding a chitinase-related receptor-like kinase, designated CHRK1, was isolated from tobacco (Nicotiana tabacum). The C-terminal kinase domain (KD) of CHRK1 contained all of the conserved amino acids of serine/threonine protein kinases. The putative extracellular domain was closely related to the class V chitinase of tobacco and to microbial chitinases. CHRK1 mRNA accumulation was strongly stimulated by infection with fungal pathogen and tobacco mosaic virus. Amino acid-sequence analysis revealed that the chitinase-like domain of CHRK1 lacked the essential glutamic acid residue required for chitinase activity. The recombinant chitinase-like domain did not show any catalytic activity for either oligomeric or polymeric chitin substrates. The recombinant KD of CHRK1 exhibited autophosphorylation, but the mutant KD with a mutation in the essential ATP-binding site did not, suggesting that CHRK1 encoded a functional kinase. CHRK1 was detected in membrane fractions of tobacco BY2 cells. Furthermore, CHRK1-GFP fusion protein was localized in plasma membranes when it was expressed in animal cells. This is the first report of a new type of receptor-like kinase containing a chitinase-like sequence in the putative extracellular domain.

Association between birth weight and insulin sensitivity in healthy young men in Korea: role of visceral adiposity

Recent studies have demonstrated decreased insulin sensitivity in individuals with low birth weight. This study was performed to examine whether abdominal obesity is a link between insulin resistance and low birth weight. We studied the relationships between birth weight and insulin secretion, insulin sensitivity, and various anthropometric indices including visceral fat area in 22 healthy young Korean adults. Birth weight correlated significantly with diastolic blood pressure (r=-0.47, P<0.05) and insulin sensitivity index (S(I)) measured by a frequently sampled intravenous glucose tolerance test (FSIGT) (r=0.54, P<0.05), but not with insulin secretory indices such as acute insulin responses during FSIGT (r=-0.35, NS) or hyperglycemic clamp (r=0.17, NS) and submaximum insulin response during hyperglycemic clamp (r=0.10, NS). S(I) correlated significantly with abdominal obesity measurements such as waist circumference (r=-0.48, P<0.05), waist-to-hip ratio (r=-0.53, P<0.05) and visceral fat area (r=-0.58, P<0.01). However, we could not find significant correlation between birth weight and any of the abdominal obesity measurements (r=-0.35 for waist-to-hip ratio, r=-0.22 for visceral fat area, and r=-0.24 for visceral-to-subcutaneous fat ratio; NS for all). The present data confirm that low birth weight is associated with insulin resistance in adult life. However, our data suggest that the association between low birth weight and insulin resistance is not mediated by abdominal obesity.

Gadolinium mesoporphyrin as an MR imaging contrast agent in the evaluation of tumors: an experimental model of VX2 carcinoma in rabbits

OBJECTIVE

We determined the enhancement features of experimentally induced malignant tumors on MR imaging with the use of gadolinium mesoporphyrin, a recently developed MR contrast agent that may be necrosis-specific.

MATERIALS AND METHODS

VX2 carcinoma was inoculated into 24 rabbit thighs. T1-weighted contrast-enhanced MR imaging with IV gadopentetate dimeglumine (2-min delay) and gadolinium mesoporphyrin (20-hr delay) was performed 3-4 days (n = 6), 6-7 days (n = 6), 10-11 days (n = 5), and 13-14 days (n = 7) after the implantation of VX2 carcinoma. All tumors were sectioned along the same plane of MR images, and a detailed MR imaging-histopathologic correlation was performed.

RESULTS

Pathologically, areas enhanced with gadolinium mesoporphyrin included necrotic tissue, viable tumor, inflammatory granulation tissue, hemorrhage, and fibrosis. On gadopentetate dimeglumine-enhanced MR images, unenhanced areas of the tumor corresponded with intratumoral necrosis and hemorrhage.

CONCLUSION

Gadolinium mesoporphyrin enhances tumor necrosis on delayed phase MR imaging; however, it is impossible to specifically depict necrosis with gadolinium mesoporphyrin because it also enhances other parts of lesions, including viable tumor.

Grass carp (Ctenopharyngodon idellus) bile may inhibit the release of renal dipeptidase from the proximal tubules by nitric oxide generation

There are many reports on acute renal failure (ARF) after ingestion of grass carp bile (CB; Ctenopharyngodon idellus). Renal dipeptidase (RDPase; EC 3.4.13.19) is a glycosylphosphatidylinositol-anchored ectoenzyme within the renal proximal tubules (PTs) and is proposed as a diagnostic enzyme of renal disease. We examined the release of RDPase following treatment with CB and various nitric oxide (NO) related compounds in porcine PTs. The RDPase release from PTs was inhibited by CB in a concentration-dependent manner and was also inhibited by sodium nitroprusside (direct NO donor) and L-arginine (NO synthase substrate) in the tested range (0-12 mM). CB-treated (0. 1 mg/ml) PTs showed a decreased RDPase activity in comparison with the control group. This inhibition was blocked by 2 mM L-NAME (NO synthase inhibitor) and U73122 (inhibitor of phosphatidylinositol-specific phospholipase C) in a concentration-dependent manner. Eel bile (0-0.1 mg/ml), used as the control, did not significantly affect the RDPase release from PTs. The NO concentration was observed as nitrite, the degradation product of the NO metabolism, increased in proportion to CB and L-arginine. The increase of nitrite to 151.5% by CB treatment (0.1 mg/ml) was blocked by 2 mM L-NAME (95.5%). When the phospholipase C pathway was blocked by 10 and 20 microM U73122, the nitrite generation decreased to 122.7 and 89.4%, respectively. These results strongly suggest that NO generation and the phospholipase C pathway affect the RDPase release from the PTs and that they may be involved in the development of ARF in vivo following CB ingestion. The release of RDPase from PTs could be a useful tool not only for this CB-caused ARF, but also for the elucidation of other biochemical mechanisms.

Safety and clinical impact of ergonovine stress echocardiography for diagnosis of coronary vasospasm

OBJECTIVES

We sought to address the issues of safety, feasibility and clinical impact of noninvasive diagnosis of coronary vasospasm (CVS).

BACKGROUND

The safety of ergonovine provocation for CVS performed outside the catheterization laboratory has been questioned.

METHODS

We performed a retrospective analysis of the results of bedside ergonovine provocation testing by monitoring left ventricular regional wall motion abnormalities (RWMAs) using two-dimensional echocardiography (Erg Echo).

RESULTS

After confirming that there was no significant epicardial coronary stenosis, Erg Echo was performed on 1,372 patients from July 1991 to December 1997. Ergonovine echocardiography was terminated prematurely in 13 patients (0.9%) because of limitations caused by side effects unrelated to myocardial ischemia. Among 1,359 completed tests, 31% (n = 421) showed positive results, with development of RWMAs in 412 tests (98%) or ST displacement in electrocardiograms of nine tests (2%). Arrhythmias developed in 1.9% (26/1,372), including transient ventricular tachycardia (n = 2) and atrioventricular block (n = 4), which were promptly reversed with nitroglycerin. There was no mortality or development of myocardial infarction. Based on the angiographic criteria of 218 patients, the sensitivity and specificity of Erg Echo for the diagnosis of CVS were 93% and 91%, respectively. Since 1994, Erg Echo has become a more popular diagnostic method than invasive spasm provocation testing in the catheterization laboratory and has comprised more than 95% of all spasm provocation tests during the last three years. In the outpatient clinic, 453 patients underwent Erg Echo safely.

CONCLUSIONS

Although this is a retrospective study in a single center, we believe that Erg Echo is highly feasible, accurate and safe for the diagnosis of CVS and can replace invasive angiographic spasm provocation testing in the catheterization laboratory.

Can the expression of histocompatibility antigen be changed by lithium?

OBJECTIVES

This study attempted to determine whether human leukocyte antigen (HLA) type changes would be caused by lithium.

METHODS

A total of 15 patients were chosen as subjects (4 males, 11 females) and completed tests in class I. Eight of the 15 patients completed tests in class II. Their mean age was 27 +/- 7 years. For an average of 51 +/- 17 days, lithium, 600-1,200 mg/day (mean daily dose: 920 +/- 211 mg) was administered for the HLA testing and then compared with the HLA type prior to the time the drug was administered. Class I type test was performed according to the Terasaki microcytotoxicity method and class II type by the Erlich polymerase chain reaction method.

RESULTS

Of the 15 subjects, 11 had changes in HLA-A, B, C types and two of the eight subjects had changes in HLA DR type.

CONCLUSION

Lithium, in the therapeutic dose, is considered to bring about changes in HLA expressions in as short a time period as 2 months.

Effects of high-fat diet and exercise training on intracellular glucose metabolism in rats

We examined the effects of high-fat diet (HFD) and exercise training on insulin-stimulated whole body glucose fluxes and several key steps of glucose metabolism in skeletal muscle. Rats were maintained for 3 wk on either low-fat (LFD) or high-fat diet with or without exercise training (swimming for 3 h per day). After the 3-wk diet/exercise treatments, animals underwent hyperinsulinemic euglycemic clamp experiments for measurements of insulin-stimulated whole body glucose fluxes. In addition, muscle samples were taken at the end of the clamps for measurements of glucose 6-phosphate (G-6-P) and GLUT-4 protein contents, hexokinase, and glycogen synthase (GS) activities. Insulin-stimulated glucose uptake was decreased by HFD and increased by exercise training (P < 0.01 for both). The opposite effects of HFD and exercise training on insulin-stimulated glucose uptake were associated with similar increases in muscle G-6-P levels (P < 0.05 for both). However, the increase in G-6-P level was accompanied by decreased GS activity without changes in GLUT-4 protein content and hexokinase activities in the HFD group. In contrast, the increase in G-6-P level in the exercise-trained group was accompanied by increased GLUT-4 protein content and hexokinase II (cytosolic) and GS activities. These results suggest that HFD and exercise training affect insulin sensitivity by acting predominantly on different steps of intracellular glucose metabolism. High-fat feeding appears to induce insulin resistance by affecting predominantly steps distal to G-6-P (e.g., glycolysis and glycogen synthesis). Exercise training affected multiple steps of glucose metabolism both proximal and distal to G-6-P. However, increased muscle G-6-P levels in the face of increased glucose metabolic fluxes suggest that the effect of exercise training is quantitatively more prominent on the steps proximal to G-6-P (i.e., glucose transport and phosphorylation).

Cationic liposome-enhanced adenoviral gene transfer in a murine head and neck cancer model

The effect of combining adenoviral vector and cationic liposomes on the efficiency of gene transfer to head and neck tumor cells was investigated. Two human and two murine cell lines were used for the screening of gene transfer efficiency using an adenoviral vector. Cationic liposome-enhanced gene transfer was checked using a murine squamous carcinoma cell line, SCCVII/SF. A considerable difference in the efficiency of gene transduction was observed among the cell lines. The combination of DOSPER and adenoviral vector containing human alkaline phosphatase showed a remarkable enhancing effect in gene transfer in vitro and in vivo, compared to the adenovirus alone or control groups. With an improvement in the efficiency of gene transfer, it may be possible not only to enhance the expression of transduced genes, but also to deliver a smaller amount of virus, as a result, reducing toxicity and the immune response against adenovirus.

The comparison of toluene determination between headspace-solid phase microextraction and headspace methods in glue-sniffer's blood and urine samples

An accurate and simple method was developed to determine the level of toluene in urine and blood quantitatively by using the gas chromatography/mass spectrometry (GC/MS) with headspace--solid phase microextraction (HS-SPME) technique. An assembly of SPME with a replaceable extraction fiber, coated with 100 microm polydimethylsiloxane, was used. The detection limit of toluene in blood and urine with HS-SPME technique was 10 times higher than that with headspace (HS) technique. To compare the HS-SPME with HS technique for the determination of toluene in biological fluids, blood and urine samples from glue sniffers were analyzed by both methods. The level of toluene by the two techniques was highly correlated: the correlation coefficient (r2) between the two sets of values were 0.98 and 0.96 in urine and blood, respectively.

Mechanism for antiplatelet effect of onion: AA release inhibition, thromboxane A(2)synthase inhibition and TXA(2)/PGH(2)receptor blockade

Antiplatelet actions of aqueous extract of onion were investigated in rat and human platelet. IC(50)values of onion extract for collagen-, thrombin-, arachidonic acid (AA)-induced aggregations and collagen-induced thromboxane A(2)(TXA(2)) formation were 0.17 +/- 0. 01, 0.23 + 0.03, 0.34 +/- 0.02 and 0.12 +/- 0.01 g/ml, respectively. [(3)H]-AA release induced by collagen (10 microg/ml) in rat platelet was decreased by onion compared to control (22.1 +/- 2.13 and 5.2 +/- 0.82% of total [(3)H]-AA incorporated, respectively). In fura-2 loaded platelets, the elevation of intracellular Ca(2+)concentration stimulated by collagen was inhibited by onion. Onion had no cytotoxic effect in platelet. Onion significantly inhibited TXA(2)synthase activity without influence on COX activity. Platelet aggregation induced by U46619, a stable TXA(2)mimetic, was inhibited by onion, indicating its antagonism for TXA(2)/PGH(2)receptor. These results suggest that the mechanism for antiplatelet effect of onion may, at least partly, involve AA release diminution, TXA(2)synthase inhibition and TXA(2)/PGH(2)receptor blockade.

Neck infection associated with pyriform sinus fistula: imaging findings

BACKGROUND AND PURPOSE

Acute suppurative neck infections associated with branchial fistulas are frequently recurrent. In this study, we describe the imaging findings of acute suppurative infection of the neck caused by a third or fourth branchial fistula (pyriform sinus fistula).

METHODS

Imaging findings were reviewed in 17 patients (11 female and six male patients, 2 to 49 years old) with neck infection associated with pyriform sinus fistula. Surgery or laryngoscopic examination confirmed the diagnoses. Fourteen patients had a history of recurrent neck infection and seven had cutaneous openings on the anterior portion of the neck (all lesions were on the left side). Imaging studies included barium esophagography (n = 16), CT (n = 14), MR imaging (n = 2), and sonography (n = 3).

RESULTS

A sinus or fistulous tract was identified in eight of 16 patients on barium esophagograms. In 14 patients, CT studies showed the inflammatory infiltration and/or abscess formation along the course of the sinus or fistulous tract from the pyriform fossa to the thyroid gland. In nine patients, CT scans showed the entire course or a part of the sinus or fistulous tract as a tiny spot containing air. MR images showed a sinus or fistulous tract in two patients, whereas sonograms could not depict a sinus or fistulous tract in three patients. All 17 patients were treated with antibiotics. In one patient, the sinus tract was surgically excised, while 15 patients underwent chemocauterization of the sinus or fistulous tract with good outcome. Follow-up was possible for 16 of the 17 patients.

CONCLUSION

When an inflammatory infiltration or abscess is present between the pyriform fossa and the thyroid bed in the lower left part of the neck, an infected third or fourth branchial fistula should be strongly suspected.

CD40L activation in circulating platelets in patients with acute coronary syndrome

The CD40-CD40L interaction, which was initially shown to have important roles in the T cell-mediated activation of B cells during humoral immune responses, is now known to have roles in activation of endothelial cells, smooth muscle cells, and macrophages within atherosclerotic plaques. Recently, CD40L expression was found in activated platelets in the thrombus in vivo and CD40L was reported to be responsible for the platelet-mediated activation of endothelial cells in vitro. To investigate the activation status of platelets in coronary artery disease patients, we tested expression levels of CD40L, and platelet-endothelial cell adhesion molecule-1 (PECAM-1/CD31) in platelets isolated from peripheral blood, using flow cytometric analysis. Twenty-nine patients with acute coronary syndrome (10 acute myocardial infarction and 19 unstable angina patients) were compared with 14 normal subjects or 14 stable angina patients. In platelets isolated from normal subjects, the expression of CD40L was not detected in all subjects. In the patients with acute coronary syndrome, the average level of CD40L showed a significant increase (p = 0.0028), while stable angina patients did not have any increase when compared to normal subjects. Patients with more complex lesions or vessel occlusion tended to have a high platelet CD40L level compared to patients who do not. The expression levels of CD31 were increased in a small portion of the ACS patients. These data indicate that the rupture of plaque and subsequent formation of thrombus may lead to the activation of CD40L expression in circulating platelets of ACS patients.