Origin of the high affinity and selectivity of novel receptors for NH4+ over K+: charged hydrogen bonds vs cation-pi interaction

[structure: see text]Given the recent report of a novel pyrazole receptor exhibiting a high selectivity for NH4+ over K+, it would be interesting to investigate the origin of this selectivity and affinity so that better receptors could be designed. On the basis of extensive theoretical studies, we conclude that the origin arises from a subtle interplay of charged H-bonds and cation-pi interactions. The approach employed herein would be very useful in the rational design of novel functional molecular systems.

HLA class II allele associations in Korean patients with pemphigus

BACKGROUND

Studies at the population level have demonstrated associations between pemphigus (pemphigus vulgaris, PV, and pemphigus foliaceus, PF) and particular HLA haplotypes, which suggests that there may be a genetic predisposition for the disease.

OBJECTIVE/METHODS

The aim of the present study was to examine the distribution/frequency pattern of HLA class II alleles (DRB1, DQA1 and DQB1) from a group of 30 Korean patients with pemphigus (15 PV and 15 PF) by PCR amplification with sequence-specific primers.

RESULTS

In PV, the frequency of DRB1*01 allele was found to be significantly high (pc = 0.0014); in PF, DRB1*01, DQA1*0302 and DQB1*0603 alleles showed positive associations with statistical significances (pc = 0.0002, 0.0007 and 0.0067, respectively), when compared with those found in Korean controls.

CONCLUSIONS

In this small-sample study, findings of allelic frequencies among Korean patients with pemphigus are somewhat different from those found in other populations.

Effect of intravenous omeprazole on recurrent bleeding after endoscopic treatment of bleeding peptic ulcers

BACKGROUND

After endoscopic treatment of bleeding peptic ulcers, bleeding recurs in 15 to 20 percent of patients.

METHODS

We assessed whether the use of a high dose of a proton-pump inhibitor would reduce the frequency of recurrent bleeding after endoscopic treatment of bleeding peptic ulcers. Patients with actively bleeding ulcers or ulcers with nonbleeding visible vessels were treated with an epinephrine injection followed by thermocoagulation. After hemostasis had been achieved, they were randomly assigned in a double-blind fashion to receive omeprazole (given as a bolus intravenous injection of 80 mg followed by an infusion of 8 mg per hour for 72 hours) or placebo. After the infusion, all patients were given 20 mg of omeprazole orally per day for eight weeks. The primary end point was recurrent bleeding within 30 days after endoscopy.

RESULTS

We enrolled 240 patients, 120 in each group. Bleeding recurred within 30 days in 8 patients (6.7 percent) in the omeprazole group, as compared with 27 (22.5 percent) in the placebo group (hazard ratio, 3.9; 95 percent confidence interval, 1.7 to 9.0). Most episodes of recurrent bleeding occurred during the first three days, which made up the infusion period (5 in the omeprazole group and 24 in the placebo group, P<0.001). Three patients in the omeprazole group and nine in the placebo group underwent surgery (P=0.14). Five patients (4.2 percent) in the omeprazole group and 12 (10 percent) in the placebo group died within 30 days after endoscopy (P=0.13).

CONCLUSIONS

After endoscopic treatment of bleeding peptic ulcers, a high-dose infusion of omeprazole substantially reduces the risk of recurrent bleeding.

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.

Stereoselectivity of macrocyclic ring-closing olefin metathesis

[reaction: see text] Macrocyclic ring-closing olefin metathesis using ruthenium catalyst 3 was performed to produce a 14-membered lactone. The E/Z ratio of lactone was high regardless of the R group (auxiliary) or the initial alkene stereochemistry. A kinetic study demonstrates that the high E/Z ratio is due to secondary metathesis reactions that isomerize the product to the thermodynamic E/Z ratio.

Redesign of primer and application of the reverse transcriptase-polymerase chain reaction and restriction fragment length polymorphism test to the DE072 strain of infectious bronchitis virus

Diagnosis of the DE072 strain of infectious bronchitis virus (IBV) by the reverse transcriptase-polymerase chain reaction (RT-PCR) and restriction fragment length polymorphism (RFLP) serotype identification test was not possible because the primer used in the RT-PCR did not amplify the S1 gene of the DE072 strain. The 3' end of the polymerase gene and the 5' end of the S2 gene of the DE072 strain were sequenced and compared with the forward and reverse RT-PCR primers, respectively. A 2-bp mismatch at the 3' end of the reverse primer was found. On the basis of these data, a degenerate primer that could amplify the S1 gene of the DE072 strain as well as eight other serotypes of the virus was synthesized. In addition, we were able to differentiate the DE072 strain from all of the other IBV strains examined by RFLP analysis of the RT-PCR product.

Sequence analysis of the hemagglutinin gene of H9N2 Korean avian influenza viruses and assessment of the pathogenic potential of isolate MS96

Sequence analysis of the hemagglutinin (HA) gene of five Korean H9N2 avian influenza virus (AIV) isolates showed that these viruses were closely related and possibly came from the same source. Phylogenetic analysis of the HA1 subunit of H9 subtype isolates revealed that Korean AIV isolates were different from isolates from the poultry markets in Hong Kong in 1997. None of the Korean AIVs had multiple basic amino acids at the HA cleavage site that confer high pathogenicity to some H5 and H7 AIVs. Phylogenetic analysis of the nucleoprotein and matrix gene demonstrated that Korean isolates cluster with Eurasian origin AIVs. The pathogenic potential of one of the isolates (MS96) was assessed after several passages in 14-day-old embryonated chicken eggs (ECE). Fourteen-day-old ECE derivatives of MS96 showed increased HA titer and embryo mortality in eggs; this was apparent after the third passage in 14-day-old ECE. Sequence analysis of the cleavage site of MS96 after the third and tenth passages in 14-day-old ECE revealed no changes in the amino acid sequence. The pathogenicity of MS96 after the tenth passage in 14-day-old eggs (MS96p10(ECE14)) was tested with 4-wk-old specific-pathogen-free chickens. The 14-day-old derivative, MS96p10(ECE14), showed wider tissue tropism and induced more severe clinical signs than the parent virus. Furthermore, after intranasal inoculation of 86-wk-old broiler breeders and 30-wk-old layers, the MS96p10(ECE14) derivative induced more severe signs of depression than the parent virus as well as a transient drop in egg production.

Bidirectional pigment granule migration in isolated retinal pigment epithelial cells requires actin but not microtubules

In the teleost retinal pigment epithelium (RPE), melanin pigment granules disperse into long apical projections in the light and reaggregate into the cell body in the dark. To investigate the cytoskeletal mechanisms responsible for these movements, we have examined the effects of cytoskeletal inhibitors on pigment granule transport in cultured, dissociated RPE cells using time-lapse video microscopy. The kinetics of pigment granule transport during normal aggregation and dispersion are quite distinct: during aggregation, all pigment granules undergo simultaneous, nonsaltatory centripetal movement (mean velocity 3.6 microm/min); during dispersion, individual granules undergo independent, bidirectional saltatations (mean velocities 3.7 microm/min centrifugal; 1.1 microm/min centripetal). Nocodazole disruption of microtubules within the RPE apical projections had little effect on the kinetics of pigment granule movement, and essentially no effect on extent of pigment granule aggregation or dispersion, or on maintenance of the fully aggregated or fully dispersed states. In contrast, cytochalasin D (CD) treatment blocked net aggregation and dispersion of pigment granules, and compromised maintenance of the fully aggregated and dispersed states. These observations suggest that the actin cytoskeleton plays an important role in both centripetal and centrifugal transport of pigment granules in teleost RPE cells.

The statistical variability of blood alcohol concentration measurements in drink-driving cases

Like many other places in the world, Hong Kong has drink-driving legislation which prohibits a driver from having in his blood alcohol exceeding a prescribed limit while in control of a motor vehicle. The accuracy of measuring this alcohol concentration is obviously of prime concern as an erroneous result can avert the administration of justice. The common practice is to deduct all errors from the measured value and compare the deducted value with the prescribed limit, so that the benefit of all errors of the measurement is given to the driver. It is therefore important for any laboratory responsible for measuring blood alcohol concentrations to identify and quantify all errors associated with the measurement. The present study examined 900 blood alcohol determinations carried out by the Hong Kong Government Laboratory (HKGL) on cases of suspected drink driving. The determinations were performed by 5 different analysts with two different sets of instruments during 1995-1997. Statistical analysis indicated that the instruments had no bearing on the random error or variability and that even though analyst was a significant factor on variability, the deviation from the mean so caused was only 0.3% and of no practical significance. When the systematic error introduced by the tolerance limits of the certified alcohol standards (purchased from the Laboratory of Government Chemists, UK) was taken into account, the total uncertainty (random plus systematic errors) of an alcohol determination at 99.5% confidence level was found to be 4%. It is recommended that laboratories engaged in blood alcohol determination should adopt similar statistical treatment of their analytical results to find out the error and to ensure that the results are independent of analyst and instrument used.

Detection of mycobacterial DNA in cervical granulomatous lymphadenopathy from formalin-fixed, paraffin-embedded tissue by PCR

Cervical tuberculous lymphadenitis is the most common form of inflammatory neck mass in Korea. The diagnosis of tuberculosis requires proof of the presence of Mycobacterium tuberculosis by acid-fast staining or bacterial growth in culture. However, these are often difficult in cervical tuberculous lymphadenitis. The aim of this study was to investigate the value of the polymerase chain reaction (PCR) technique for detection of mycobacteria in routinely processed tissue sections of cervical granulomatous lymphadenopathy. In this retrospective study, twenty formalin-fixed, paraffin-embedded biopsy specimens from clinically and/or histopathologically diagnosed cervical granulomatous lymphadenopathy were analyzed for mycobacterial DNA by PCR. Two different primers to amplify mycobacterial-common 383-base pair (bp) DNA and Mycobacterium tuberculosis-complex-specific 123-bp DNA were used. Positive PCR products were sequenced directly. Mycobacterial-common DNA (383-bp positive) was found in 10 of the 20 cases. Among them, 7 cases were PCR positive with both primer sets. These seven cases can be considered as tuberculosis. The other three cases indicated possible atypical mycobacteriosis. PCR is a useful technique for the demonstration of mycobacterial DNA fragments in patients with clinically suspected cervical tuberculous lymphadenitis who have acid fast-negative histology and/or unsuccessful mycobacterial cultures.

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.

Immunomodulating activity of a polysaccharide isolated from Mori Cortex Radicis

The immunomodulating activity of a polysaccharide isolated from Morus alba (PMA) root bark was examined in murine splenic lymphocytes. PMA enhanced proliferation of splenic lymphocytes in a synergistic manner in the presence of mitogens. However, PMA suppressed primary IgM antibody production from B cells, which was activated with lipopolysaccharide, a polyclonal activator, or immunized with a T-cell dependent antigen sheep red blood cells. Our observations showed that the immunomodulating activity of PMA increased lymphocyte proliferation and that PMA decreased antibody production from B cells, which was distinct from those of other plant-originated polysaccharides.

Distinct clinicopathologic and genetic profiles in sporadic gastric cancer with different mutator phenotypes

A subset of sporadic gastric cancers (GC) exhibits microsatellite instability (MSI). To define the precise role of MSI in GC, a total of 100 patients with sporadic GC were classified into three groups, i.e., high-frequency MSI (MSI-H), low-frequency MSI (MSI-L), and microsatellite stable (MSS), based on 10 microsatellite markers. Mutational analyses of TGFbetaRII, IGFIIR, BAX, MSH3, MSH6, E2F4, MSH2, MLH1, and TP53 genes, and methylation and protein expression of MLH1 and MSH2 were performed and correlated. Twenty-seven percent of GC showed MSI at least in one locus and could be further graded as MSI-H (14%) and MSI-L (13%). No clinicopathologic difference was noted between GC with MSI-L and MSS. Compared with GC with MSI-L or MSS, GC with MSI-H had a significantly higher frequency of antral location, intestinal subtype, H. pylori seropositivity, but a lower incidence of lymph node metastasis, and displayed a higher frequency of frameshift mutations of TGFbetaRII, IGFIIR, BAX, MSH3, and E2F4 genes but a lower incidence of TP53 mutations. Furthermore, hypermethylation of the MLH1 promoter was responsible for the loss of protein function in 13 of 14 MSI-H tumors. It was concluded that a specific phenotype and a distinct profile of genetic alterations exist in MSI-H GC. We speculate that epigenetic inactivation of MLH1 by methylation plays a crucial role in initiating such a pathway of carcinogenesis. In contrast, GCs with MSS and MSI-L exhibit clinicopathologic features that are distinct from MSI-H tumors and have a higher frequency of TP53 mutations, suggesting that they may evolve through an entirely different pathway.

Distinct clinicopathologic and genetic profiles in sporadic gastric cancer with different mutator phenotypes

A subset of sporadic gastric cancers (GC) exhibits microsatellite instability (MSI). To define the precise role of MSI in GC, a total of 100 patients with sporadic GC were classified into three groups, i.e., high-frequency MSI (MSI-H), low-frequency MSI (MSI-L), and microsatellite stable (MSS), based on 10 microsatellite markers. Mutational analyses of TGFbetaRII, IGFIIR, BAX, MSH3, MSH6, E2F4, MSH2, MLH1, and TP53 genes, and methylation and protein expression of MLH1 and MSH2 were performed and correlated. Twenty-seven percent of GC showed MSI at least in one locus and could be further graded as MSI-H (14%) and MSI-L (13%). No clinicopathologic difference was noted between GC with MSI-L and MSS. Compared with GC with MSI-L or MSS, GC with MSI-H had a significantly higher frequency of antral location, intestinal subtype, H. pylori seropositivity, but a lower incidence of lymph node metastasis, and displayed a higher frequency of frameshift mutations of TGFbetaRII, IGFIIR, BAX, MSH3, and E2F4 genes but a lower incidence of TP53 mutations. Furthermore, hypermethylation of the MLH1 promoter was responsible for the loss of protein function in 13 of 14 MSI-H tumors. It was concluded that a specific phenotype and a distinct profile of genetic alterations exist in MSI-H GC. We speculate that epigenetic inactivation of MLH1 by methylation plays a crucial role in initiating such a pathway of carcinogenesis. In contrast, GCs with MSS and MSI-L exhibit clinicopathologic features that are distinct from MSI-H tumors and have a higher frequency of TP53 mutations, suggesting that they may evolve through an entirely different pathway.

Clinical outcome of internal iliac artery occlusions during endovascular treatment of aortoiliac aneurysmal diseases

PURPOSE

To determine the clinical outcome of hypogastric artery occlusion in patients who underwent endovascular treatment of aortoiliac aneurysmal disease.

MATERIAL AND METHODS

From January 1994 to March 1998, 94 patients underwent endovascular treatment of aneurysmal diseases involving the infra-abdominal aorta or iliac arteries. Preoperative and intraoperative radiologic data were reviewed. Discharge summaries, clinic visits, and phone calls formed the basis for clinical follow-up, with a mean follow-up period of 7.3 months (range, 1-24 months).

RESULTS

Because of the anatomy of the aneurysms, 28 patients required occlusion of one or more hypogastric arteries. One of the 28 patients died of unrelated causes before follow-up. Seven (26%) of the remaining 27 patients developed symptoms attributable to the hypogastric artery occlusions. Five patients developed new buttock or thigh claudication; of these five patients, three with initially mild symptoms noted complete or near complete resolution of symptoms upon follow-up. One patient with originally significant claudication at 2-year follow-up noted near resolution of symptoms. The other patient with severe pain did not improve significantly on final 1-year follow-up before his death (of unrelated causes). Other clinical complications were worsening sexual function in one patient and a nonhealing sacral decubitus ulcer that developed in a debilitated patient in the postoperative setting, which required surgery. No bowel ischemia was observed.

CONCLUSION

When treating aortoiliac aneurysmal disease through an endovascular approach, the occlusion of internal iliac artery is often necessary but carries with it a small but finite chance of morbidity.

The standard of reporting of health-related quality of life in clinical cancer trials

The standard of reporting of randomized controlled trials (RCTs) is important to the interpretation of outcomes such as health-related quality of life (HRQL). HRQL is used increasingly as an outcome in clinical cancer trials.

DESIGN

All 1997 issues of 36 selected journals were hand searched to identify original articles that included the term "quality of life" in the title, abstract, keywords or methods. Studies were included if they were RCTs and addressed cancer-related topics. A checklist to assess the adequacy of reporting of HRQL was developed based on a guideline previously published by an expert panel. Two unblinded reviewers applied the quality of life reporting (QLR) and CONSORT checklists, along with an instrument to assess the likelihood of bias to each selected RCT.

RESULTS

72 articles were identified of which 20 were RCTs and cancer-related. For these 20 reports the median number of items in the QLR checklist that were adequately reported is 42% (range 15% to 85%). The median number of items in the CONSORT checklist that were adequately reported is 70% (range 47% to 95%). The mean score for the instrument to assess the likelihood for bias is 2.6 (95% CI 2. 08-3.12).

CONCLUSIONS

The current standard of reporting of HRQL needs to be improved. Major deficiencies that should be addressed are failure to provide a rationale for HRQL assessment and inadequate description of methodology. Development and application of structured formats for presentation of HRQL may help to improve the standard of reporting of HRQL in the literature.

Clinical constellation of annular erythema associated with anti-Ro/La autoantibodies

Annular erythema (AE) associated with anti-Ro (SSA) and/or La (SSB) autoantibody in patients with Sjögren syndrome (SS) or with SS/systemic lupus erythematosus overlap syndrome (SS/SLE), has recently been described in Orientals, and it may be a counterpart of annular skin lesion of the subacute cutaneous LE seen mostly in Caucasians. The author examined five Korean AE patients in respect to dinical diversity. In this small-sample study, subtle differences appeared between individual cases regarding the serologic features and the diagnoses of the disease. Among the five cases, four had circulating anti-Ro and anti-La antibodies, and one had only anti-La. Regarding the diagnosis, one was SS/SLE, two were primary SS, and the remaining two were only "AE associated with anti-Ro/La antibody". There seem to be a wide clinical spectrum in the disease expression of AE associated with anti-Ro/La autoantibody than previously thought.

Multivessel coronary stenting versus bypass surgery in patients with multivessel coronary artery disease and normal left ventricular function: immediate and 2-year long-term follow-up

BACKGROUND

Compared with coronary artery bypass surgery (CABG), the clinical benefits of intracoronary stenting have not been established in patients with multivessel coronary lesions.

METHODS AND RESULTS

To compare the clinical outcomes of intracoronary stenting with that of CABG, we reviewed the outcomes of patients with multivessel coronary artery disease from an observational database. Two hundred consecutive patients with multivessel coronary artery disease and normal left ventricular function were evaluated. In 200 patients, multivessel stenting was performed in 100 and CABG was performed in 100. Complete revascularization was achieved in 95% in the CABG group and in 69% in the stent group (P <.05). The duration of total hospital stay and coronary care unit admission was significantly shorter in the stent group (P <.05). The long-term survival was similar between the 2 groups. There were no significant differences of cardiac events between the 2 groups except for the recurrence of angina (19% in stenting vs 8% in CABG, P =.03) and target lesion revascularization (19% vs 2%, P <.01) in the patients with stents.

CONCLUSIONS

In selected patients with multivessel coronary artery disease and normal left ventricular function, intracoronary stenting may offer an effective alternative to coronary bypass surgery.

Pressure-derived fractional collateral blood flow: a primary determinant of left ventricular recovery after reperfused acute myocardial infarction

OBJECTIVES

We evaluated the relation between pressure-derived fractional collateral flow (PDCF) and left ventricular (LV) recovery after reperfused acute myocardial infarction (AMI).

BACKGROUND

The functional significance of collateral flow remains uncertain in AMI.

METHODS

The PDCF was measured in 70 patients with first AMI (pain onset <12 h) treated with primary angioplasty (PA), being determined by simultaneous measurement of mean aorta pressure (Pa), distal coronary pressure during the balloon occlusion (Poc), and central venous pressure (CVP): (Poc - CVP)/(Pa - CVP)*100. Sufficient collateral (group I) was defined as PDCF index >24% and insufficient collateral (group II) as PDCF index <24%. Echocardiography was performed before, and on day 3, day 7, and day 30 after PA. Wall-motion recovery index (RI) was obtained by dividing the number of improved wall-motion segments (>grade 1) at follow-up by the number of abnormal wall-motion segments within the infarct zone at baseline.

RESULTS

Baseline characteristics were similar between both groups. Peak levels of creatine kinase were lower in group I than in group II (2,600+/-1,900 U/liter vs. 4,100+/-3,000, p < 0.05). At one month, infarct zone wall-motion score index (1.65+/-0.54 vs. 2.31+/-0.46, p < 0.01) and LV volume indexes were smaller in group I than in group II, whereas, LV ejection fraction was higher in group I than in group II (52.8+/-8.3 vs. 45.9+/-9.0, p < 0.01). The PDCF index was the strongest predictor of RI at one month (r = 0.61, p < 0.01). Time to reperfusion was not related to RI at one month. However, it was significantly related to RI in group II (r = -0.34, p < 0.05).

CONCLUSIONS

The LV recovery after reperfused AMI is primarily determined by PDCF and is less dependent on time to reperfusion in patients with sufficient collaterals.

The demonstration of Pasteurella multocida in the alimentary tract of chickens after experimental oral infection

A selective medium containing polymyxin B, crystal violet, thallous acetate, bacitracin and cycloheximide in 10% sheep blood dextrose starch agar, and a modified Pasteurella multocida-specific polymerase chain reaction (PCR) assay were developed for the respective isolation and detection of P. multocida from chicken alimentary tract. The selective medium and the PCR assay were highly sensitive, detecting 100 cfu from colon contents. These techniques were used to follow the localisation of an orally administered virulent P. multocida in chickens. Pasteurellae could be isolated from the crop of some birds up to 30 h, occasionally from other sites after 28 h. It was concluded that the crop was a likely site for colonisation and that infection was most likely to occur through the mucosa of the jejunum or ileum.

Stent placement for ostial left anterior descending coronary artery stenosis: acute and long-term (2-year) results

This study was performed to assess the acute and long-term results of elective stenting for the treatment of ostial left anterior descending coronary artery (LAD) stenosis. One hundred and eleven consecutive patients with ostial LAD stenting were included for this study. Follow-up angiography was performed at 6 months and clinical evaluation at regular intervals after stenting. Procedural success rate was 97.3%. Four patients developed non-Q myocardial infarction and one patient underwent emergency bypass surgery due to a large dissection after stenting. Angiographic restenosis rate was 26.1% (18/69), and target lesion revascularization rate 11.7%. The final luminal diameter after stenting was the only predictor of angiographic restenosis. Clinical follow-up was obtained in all patients at 21.5 +/- 16.0 months. Two patients died during the follow-up. Event-free survival rate was 84.6 +/- 3.8%. In conclusions, stenting with or without debulking atherectomy may be considered as an acceptable therapeutic option for the treatment of ostial LAD stenosis.

Detection of radiation effects using recombinant bioluminescent Escherichia coli strains

Effects of ionizing radiation (0.1-500 Gy) on recombinant Escherichia coli cells containing the stress promoters recA, grpE, or katG, fused to luxCDABE, were characterized by monitoring transcriptional responses reflected by the bioluminescent output. The minimum dose of gamma-irradiation detected by E. coli DPD2794 (recA::luxCDABE) was about 1.5 Gy, while the maximum response was obtained at 200 Gy. The amount of emitted bioluminescence increased proportionally with the gamma-ray doses which were found to elicit a DNA damage response in a range of 1-50 Gy. In addition, the cell growth rate was severely, but transiently, retarded by about 50 Gy. Quantification of the gamma-ray dose may be possible using the recA promoter fusion, since linear enhancement of the bioluminescence emission with increasing gamma-ray dose was observed. Other irradiated strains (50 Gy) responsive to either oxidative stress (DPD2511, katG::luxCDABE) or protein-damaging stress (TV1061, grpE::luxCDABE) did not display an increased bioluminescent output, while DPD2794 irradiated by the same dose of gamma-rays gave a significant bioluminescent output. This indicates that the recA promoter is the one most suitable for developing a biosensor for ionizing radiation.

Monitoring of extracellular pyruvate, lactate, and ascorbic acid during cerebral ischemia: a microdialysis study in awake gerbils

In vivo microdialysis coupled with liquid chromatography was developed for the continuous monitoring of brain neurochemicals during cerebral ischemia in awake, free moving gerbils. The dead volume of the microdialysis system was estimated to be less than 30 microl. The detection limits of the present assay were 0.2 to 2.0 microM for analytes at a signal to noise ratio of five. To validate this assay, a focal cerebral ischemia was produced by occlusion of one common carotid artery for 60 min and then reperfusion for additional 3 h in awake gerbils. A microdialysis probe was inserted into the striatum of the gerbil. Dialysates were autoinjected and analyzed extracellular pyruvate, lactate, and ascorbic acid by liquid chromatography with a UV detector during cerebral ischemia. Significant changes of pyruvate and the lactate/pyruvate ratio were observed. Biphasic and dynamic changes in ascorbic acid and lactate were proposed to correlate a secondary damage. This assay can be used as a tool to study dynamic changes of brain neurochemicals in awake animals.

Intravascular ultrasonic predictors of angiographic restenosis after long coronary stenting

The intravascular ultrasound (IVUS) criteria for stent optimization have not been determined in stenting long lesions. We evaluated the predictors of angiographic restenosis and compared it with stent lumen cross-sectional area (CSA) and stent length between short (stent length <20 mm) and long (> or =20 mm) coronary stenting. IVUS-guided coronary stenting was successfully performed in 285 consecutive patients with 304 native coronary lesions. Six-month follow-up angiogram was performed in 236 patients (82.8%) with 246 lesions (80.9%). Results were evaluated using conventional (clinical, angiographic, and IVUS) methods. The overall angiographic restenosis rate was 22.8% (56 of 246 lesions) (short stent 17.6% vs. long stent 32.2%, p = 0.009). Using multivariate logistic regression analysis, the independent predictors of angiographic restenosis were the IVUS stent lumen CSA (odds ratio 1.51, 95% confidence intervals 1.18 to 1.92, p = 0.001) and stent length (odds ratio 0.95, 95% confidence intervals 0.91 to 1.00, p = 0.039). The angiographic restenosis rate was 54.8% for stent lumen CSA of <5.0 mm2 (short stent 37.5% vs. long stent 73.3%, p = 0.049), 27.4% for CSA between 5.0 and 7.0 mm2 (short stent 24.1% vs. long stent 31.7%, p = 0.409), 10.5% for CSA between 7.0 and 9.0 mm2 (short stent 10.0% vs. long stent 12.5%, p = 0.772), and 11.4% for stent lumen CSA of > or =9.0 mm2 (short stent 10.4% vs. long stent 13.3%, p = 0.767) (p = 0.001). Compared with short coronary stenting, long coronary stenting is effective treatment modality to cover long lesions with comparable long-term clinical outcomes in cases of stent lumen CSA of > or =7.0 mm2. Regardless of the stent length, the most important factor determining angiographic restenosis was the IVUS stent lumen CSA in relatively large coronary artery lesions.