Gene expression in CD34(+) cells from normal bone marrow and leukemic origins

INTRODUCTION

To address the molecular regulation of hematopoiesis and the complex mechanism in leukemogenesis, we established the first catalogs of genes expressed in normal bone marrow and leukemia CD34(+) cells.

MATERIALS AND METHODS

CD34(+) cell cDNA libraries were constructed using mRNA from adult bone marrow and from a case of acute myeloid leukemia-M5 transformed from myelodysplastic syndrome (MDS-AML). Expressed sequence tags (ESTs) and full-length cDNAs were generated by sequencing and were annotated using bioinformatic tools.

RESULTS

From a total of 4142 ESTs obtained from normal bone marrow, 3424 meaningful tags were integrated into 1630 clusters, representing 622 known genes, 522 dbEST entries and 486 novel sequences. Out of 5382 ESTs from MDS-AML, 1985 clusters were produced based on the analysis of 4321 useful ESTs, including 711 known genes, 657 known ESTs and 617 novel sequences. Among 251 transcripts found in both bone marrow and MDS-AML EST datasets and those present in only one dataset, 58 showed statistically significant differences in EST copy numbers between the two tissues (P<0.05). Twenty putative full-length cDNAs for novel genes were also cloned from the MDS-AML library.

CONCLUSION

The distinct gene expression patterns in MDS-AML-CD34(+) cells as compared to normal control cells may contribute to the development and/or maintenance of the malignant phenotypes of leukemia cells.

New advances in lung cancer chemotherapy: topotecan and the role of topoisomerase I inhibitors

Objective tumor responses and survival rates with standard chemotherapy options for small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC) have been disappointing. However, several promising new classes of agents have emerged in recent years, including the taxanes, mitotic spindle inhibitors, antimetabolites, and topoisomerase I and II inhibitors. The molecular target of several of these new agents is topoisomerase I, an enzyme that is essential for DNA replication and is up-regulated in tumor cells. Inhibition of this enzyme by drugs such as topotecan and irinotecan leads to cell death and is the basis for their anticancer activity. The process of DNA replication is halted by the covalent binding of the drug in a topoisomerase I drug/DNA ternary reaction intermediate. The pharmacokinetics of the approved regimen--a 30-min infusion daily for 5 days at 21-day intervals--are well defined, with proportional increases in the area under the plasma concentration-time curve, peak plasma concentration, and steady state concentration following application of higher doses. The antitumor activities of both the intravenous and oral formulations of topotecan have been tested in clinical trials. Topotecan is well tolerated and has demonstrated good efficacy in patients with relapsed SCLC when administered as monotherapy or in combination regimens as first-line or second-line therapy. Preliminary trials also indicate that topotecan is well tolerated and has activity in the first-line treatment of NSCLC. In this article an overview of new agents in lung cancer chemotherapy is provided, with particular attention paid to the topoisomerase I inhibitors. A review of topotecan--the first topoisomerase I inhibitor to be approved for second-line therapy in SCLC--is presented as an illustration of the promise these new agents hold for the treatment of SCLC and NSCLC.

The application of intramolecular radical cyclizations of acylsilanes in the regiospecific formation of cyclic silyl enol ethers

Acylsilanes with terminal alpha-stannyl bromide or xanthate functionalities are prepared. Alpha-stannyl radicals generated from these acylsilanes undergo intramolecular cyclizations to give cyclic silyl enol ethers regiospecifically. The radical processes involve radical cyclization, Brook rearrangement, and beta-fragmentation in sequence. A tributylstannyl group serves as the radical leaving group. The newly formed sigma-bond and pi-bond are located between the same two carbon atoms. This approach is limited to the formation of five-membered rings. In another route, omega-bromo-alpha-phenylsulfonylacylsilanes are synthesized. The radical cyclizations of these alpha-sulfonylacylsilanes also give cyclic silyl enol ethers. The phenylsulfonyl moiety is the radical leaving group in this system. Furthermore, the newly formed sigma-bond and pi-bond are located at adjacent positions sharing a single carbon atom. The latter approach is effective for both five- and six-membered ring formation.

Rottlerin stimulates metallothionein gene expression but inhibits metal transport in Chinese hamster ovary cells

Metallothionein (MT) can be induced by various metals. We have shown previously that H7, a protein kinase C (PKC) inhibitor, inactivates metal-induced MT gene expression. To investigate whether a specific PKC isoform is involved in the induction process, inhibitors for various PKC isoforms were administered to cadmium-resistant Chinese hamster ovary (Cd(R)) cells. None of the inhibitors used can reduce metal-induced MT gene expression. However, a PKCdelta inhibitor, rottlerin, induced MT mRNA expression in Cd(R) cells in the presence or absence of Cd. Notably, the induction occurs through the activation of the MT transcriptional factor (MTF-1) and is not related to an increase of metal influx. Furthermore, metal accumulation is reduced in the presence of rottlerin. Pulse-labeling analysis indicated that MT protein synthesis increased in Cd(R) cells upon rottlerin treatment. These results suggest that rottlerin blocks metal transport but stimulates MT synthesis in Cd(R) cells. Since rottlerin is capable of reducing the cellular accumulation of Cd, it was expected that the cytotoxic effect of Cd would decrease in the presence of rottlerin. Treating the parental cell of Cd(R) with Cd and rottlerin together indeed showed a decline of cytotoxicity compared to cells treated with Cd alone. We further examined how MTF-1 was activated by rottlerin. Rottlerin-induced MTF-1 activity was not affected in Cd(R) cells by the addition of EDTA. It was, however, diminished by administering an intracellular Zn chelator, TPEN. The result implies a mobilization of intracellular Zn ions after rottlerin treatment in Cd(R) cells. To investigate whether the described results occur in all types of cells, another cell line (GH(3)) was used to study the effect of rottlerin on MT gene expression. The result revealed that rottlerin did not increase the amount of MT mRNA in GH(3) cells. This differential effect between cell lines may be useful for investigating the regulatory mechanism of MT gene expression.

Telomerase activity in human bladder tumors and bladder washing specimens

Telomerase appears to be an important factor for the control of cellular proliferation and tumorigenesis. Enzyme activity dramatically increases in almost all human tumors. The purpose of our study was to evaluate the role of telomerase activity as a marker for bladder cancer diagnosis and follow-up. By using the PCR-ELISA based on the TRAP (telomerase repeat amplification protocol) method, telomerase activity of bladder tumors (n = 77), normal-appearing adjacent tissues (n = 21) and bladder washings (n = 37) were analyzed. Telomerase activity was detected in 87% (67/77) of cancer tissues and in 38% (8/21) of normal-appearing adjacent tissues. However, the levels of enzyme activity were significantly higher in cancer tissues than in normal-appearing adjacent tissues (p < 0.05). Telomerase activity in bladder cancer tissues was not correlated to the tumor stage or grade. During a 26 months follow-up period, disease progression occurred in 66.7% of patients with invasive tumors where telomerase activity of the normal-appearing adjacent tissue was detectable, as compared to only 14.3% for patients who showed undetectable telomerase activity in adjacent, normal-appearing tissues (p = 0.094). When telomerase activity of bladder washing fluid was compared with its corresponding tumors, sensitivity of detection was 81% and specificity was 75%. In contrast, urine cytology only yielded a sensitivity of 31% in the detection of cancer. The detection ability between telomerase activity measurement in washing fluid and cytological examination had a trend toward the telomerase measurement identifying more cancer cases than the cytologic examination (p = 0.07). In conclusion, telomerase activity is present in early-stage bladder cancer and is a potential molecular marker for bladder tumors diagnosis. The expression of telomerase activity in normal-appearing mucosa adjacent to bladder tumor is probably an indicator of disease progression. Using the telomerase activity to detect exfoliated cells in bladder washing fluids could be a useful method in adjunct to urine cytology and cystoscopy in establishing the diagnosis and follow-up of bladder cancer.

Effects of verapamil on coronary vascular resistance in rabbits: measurement with pulsed Doppler velocimetry

BACKGROUND

Verapamil is an effective vasodilator. The purpose of this study was to investigate the in vivo effect of verapamil on coronary blood flow velocity and vascular resistance in anesthetized, open-chest rabbits.

METHODS

Twenty-one male New Zealand white rabbits were anesthetized, and a 3-mm suction-type pulsed Doppler velocimeter probe was applied to the proximal part of the left anterior descending coronary artery after median sternotomy. The rabbits received intravenous bolus infusion of 4 different doses of verapamil (0.01 mg/kg, n = 5; 0.1 mg/kg, n = 5; 1 mg/kg, n = 5, and 10 mg/kg, n = 6). The percent changes in coronary blood flow velocity and coronary vascular resistance were examined.

RESULTS

There was 10.0+/-1.6% increase in coronary blood flow (CBF) and 12.5+/-1.9% reduction in coronary vascular resistance (CVR) after infusion of 0.01 mg/kg of verapamil. The CBF increased 23.0+/-9.5% and CVR decreased 24.2+/-5.2% after infusion of 0.1 mg/kg of verapamil. Infusion of 1 mg/kg of verapamil induced 34.8+/-10.5% increase in CBF and 32.6+/-2.5% reduction in CVR. The CBF increased 41.1+/-14.8% and CVR decreased 45.1+/-5.4% after infusion of 10 mg/kg of verapamil.

CONCLUSIONS

Compared with baseline condition, all doses of verapamil increased coronary blood flow velocity and decreased coronary vascular resistance significantly in anesthetized, open-chest rabbits.

Comparison of hand-assisted laparoscopic nephroureterectomy with open surgery for upper urinary tract tumor

Herein we report on our initial experience in performing nephroureterectomy by hand-assisted laparoscopic surgery, and compare the results with those performed by traditional open methods. From December 2000 to September 2001, 10 patients with upper urinary tract tumors underwent hand-assisted laparoscopic nephroureterectomy. Except for one patient who required elective conversion to open surgery due to renal vein injury, this cohort of 9 patients was compared to a group of 35 patients who had received traditional open nephroureterectomy over the last 2 years. Demographic, intraoperative and postoperative data were compared retrospectively. These two groups were similar in age, body mass index, operation time and time to postoperative oral intake. However, the hand-assisted laparoscopy group was found to have significantly less blood loss, less need for parenteral narcotic and a shorter length of time needed for postoperative hospitalization than the open group. Thus, in this report we have demonstrated hand-assisted laparoscopic nephroureterectomy to be a safe and efficacious treatment of malignant urinary collecting tumors. We believe the benefits of this minimally invasive surgery make it a viable alternative technique for management of upper urinary tract tumor.

RT-PCR reveals muscarinic acetylcholine receptor mRNA in the pre-Bötzinger complex

Muscarinic receptors mediate the postsynaptic excitatory effects of acetylcholine (ACh) on inspiratory neurons in the pre-Bötzinger complex (pre-BötC), the hypothesized site for respiratory rhythm generation. Because pharmacological tools for identifying the subtypes of the muscarinic receptors that underlie these effects are limited, we probed for mRNA for these receptors in the pre-BötC. We used RT-PCR to determine the expression of muscarinic receptor subtypes in tissue punches of the pre-BötC taken from rat medullary slices. Cholinergic receptor subtype M(2) and M(3) mRNAs were observed in the first round of PCR amplification. All five subtypes, M(1)-M(5), were observed in the second round of amplification. Our results suggest that the majority of muscarinic receptor subtypes in the pre-BötC are M(2) and M(3), with minor expression of M(1), M(4), and M(5).

Retroperitoneal laparoscopic nephrectomy in the treatment of incontinence from ectopic ureter with renal hypoplasia in the child--a case report

Unilateral single vaginal ectopic ureteral opening with ipsilateral hypoplastic kidney is a rare disease. It is classically presented with continuous urinary incontinence, but a normal voiding pattern after successful toilet training. The kidneys associated with this condition are usually nonfunctional and nephrectomy is the treatment of choice to cure the incontinence. We present a 7-year old girl with such a problem successfully treated by retroperitoneal laparoscopy. The patient resumed her normal unrestricted activity level on postoperative day 3. She was free of symptoms related to the operation during a 6-year follow-up period. It is suggested from this case that despite the reduced working space in children, retroperitoneal laparoscopic nephrectomy in the treatment of small kidney with complications is a feasible procedure.

Emergence of reduced susceptibility and resistance to fluoroquinolones in Escherichia coli in Taiwan and contributions of distinct selective pressures

A survey of 1,203 Escherichia coli isolates from 44 hospitals in Taiwan revealed that 136 (11.3%) isolates were resistant to fluoroquinolones and that another 261 (21.7%) isolates had reduced susceptibility. Resistance was more common in isolates responsible for hospital-acquired (mostly in intensive care units) infections (17.5%) than in other adult inpatient (11.4%; P = 0.08) and outpatient isolates (11.9%; P > 0.1). Similarly, reduced susceptibility was more common in isolates responsible for hospital-acquired infections (30.9%) than in other adult inpatient (21.0%; P = 0.04) and outpatient (21.4%; P = 0.06) isolates. Isolates from pediatric patients were less likely to be resistant (1.3 versus 12.0%; P < 0.01) but were nearly as likely to have reduced susceptibility (17.7 versus 21.9%; P > 0.1) as nonpediatric isolates. There was an inverse relationship in the proportion of isolates that were resistant versus the proportion that had reduced susceptibility among isolates from individual hospitals (R = 0.031; P < 0.05). In an analysis of isolates from two hospitals, all 9 resistant strains possessed double point mutations in gyrA and all 19 strains with reduced susceptibility strains had single point mutations; no mutations were found among fully susceptible strains. Risk factors for resistance included underlying cancer (odds ratio [OR], 83; 95% confidence interval [CI(95)], 7.3 to 2,241; P < 0.001), exposure to a quinolone (OR, undefined; P = 0.02), and exposure to a nonquinolone antibiotic (OR, 20; CI(95), 2.2 to 482; P < 0.001); underlying cancer was the only independent risk factor (OR, 83; CI(95), 8.6 to 807; P < 0.001). There were no significant associations between any of these factors and reduced susceptibility. Whereas acute and chronic quinolone use in cancer patients is a major selective pressure for resistance, other undetermined but distinct selective pressures appear to be more responsible for reduced susceptibility to fluoroquinolones in E. coli.

Real-time PCR for rapid genotyping of angiotensin-converting enzyme insertion/deletion polymorphism

OBJECTIVE

To develop a real-time PCR technique for detection of the insertion/deletion (I/D) polymorphism of angiotensin-converting enzyme (ACE) gene.

DESIGN AND METHODS

Three primers were designed for performing real-time PCR in the presence of SYBR Green I as flurochrome followed by melting curve analysis. Forty human genomic DNA that have been genotyped by two-rounds of conventional PCR were used for evaluation of this technique.

RESULTS

Melting curve analysis indicated the melting peak at 73.9 degrees C and 76.2 degrees C corresponding to the presence of I and D alleles, respectively. Comparable genotyping results were obtained by both conventional and real-time PCR. Besides, the mistyping of ID allele individuals by the first run of conventional PCR were accurately genotyped by single-tube real time PCR.

CONCLUSIONS

The real-time PCR method presented in this study provides a rapid and sensitive way for genotyping of ACE gene that may be suitable for large-scale clinical and epidemiologic study.

[Clinical study on treatment of chronic bronchitis by tracheitis plaster]

OBJECTIVE

To study the clinical effect and mechanism of Tracheitis Plaster (TP) in treating chronic bronchitis.

METHODS

TP is consisted of ephedra, almond, pinellia tuber, earthworm and white mustard seed. Patients were randomly divided into two groups, 59 patients in the treated group were treated with TP sticking on acupoints Dingchuan, Dashu, Fengmen, Feishu and Xinshu at back along both sides of thoracic vertebrae 1-6 and the 25 patients in the control group were treated with intramuscular injection of Siqikang. The times of treatment for both groups were 20. Clinical symptoms, X-ray chest film, level of immunoglobulin and T-lymphocyte subsets were recorded before and after treatment, and follow-up were carried out 0.5-1 year later.

RESULTS

The clinical total effective rate was 93.2% and the X-ray improvement rate was 40.7% in the treated group, while in the control group, 80.0% and 20.0% respectively. Half and 1 year follow-up studies showed the total effective rate in the treated group was 91.5% and 89.8% respectively, which was significantly higher than that in the control group (80.0% and 76.0%) respectively (P < 0.05). The improvement in levels of IgG and CD8 in the treated group was also superior to those in the control group (P < 0.05).

CONCLUSION

TP is a highly effective transcutaneous absorbent with promising long-term effect, it could regulate the immune function.

Role of intraventricular dispersion of early diastolic filling in indicating left ventricular diastolic dysfunction: assessment by color M-mode inflow propagation velocity

The intraventricular to mitral E velocity ratio (IvE/MvE) and the color M-mode Doppler inflow propagation velocity (LVIPV) were evaluated in 36 healthy controls and 33 patients with hypertension and/or ischemic heart disease. The intraventricular E velocity was significantly lower than the mitral E velocity in the control group (52 vs. 68 cm/s, p < 0.001), but they are similar in the disease group (59 vs. 63 cm/s, p = nonsignificant). Compared with the control group, the disease group had a higher IvE/MvE (0.95 +/- 0.28 vs. 0.78 +/- 0.23, p < 0.01). Nevertheless, the LVIPV was not significantly different between the disease and control groups (53 +/- 14 vs. 56 +/- 13 cm/s, p = nonsignificant). The LVIPV did not correlate with the IvE/MvE (r = 0.202, p = nonsignificant). Therefore, an intraventricular dispersion of early diastolic filling does not seem to indicate impaired left ventricular relaxation.

Mixed-chain phospholipids: structures and chain-melting behavior

It has long been established that diacyl phospholipids isolated from animal cell membranes are predominantly of a mixed-chain variety, meaning that the sn-1 and sn-2 acyl chains are saturated and unsaturated acyl chains, respectively. In general, monoenoic and dienoic acids are found in the sn-2 acyl chain of phosphatidylcholine (PtdCho), whereas polyenoic acids are in phosphatidylethanolamine (PtdEth). These unsaturated chains contain only cis-double bonds, which are always methylene-interrupted. In recent years, the structures and the chain-melting behavior of mixed-chain PtdCho and PtdEth have been systematically studied in this laboratory. Specifically, we have examined the effects of chain unsaturation of the sn-2 acyl chain on the phase transition temperature (Tm) of many PtdCho and PtdEth by high-resolution differential scanning calorimetry (DSC). The Tm values, for instance, obtained from all-unsaturated mixed-chain PtdEth derived from a common precursor can be grouped together according to their chemical formula to form a Tm-diagram. Hence, all the Tm values can be compared simply, systematically, and simultaneously using the Tm-diagram. In addition, the energy-minimized structures of mixed-chain phospholipids containing different numbers/positions of methylene-interrupted cis-double bonds have been simulated by molecular mechanics calculations (MM). In this review, the results of our MM and DSC studies carried out with various mixed-chain phospholipids are summarized. In addition, we emphasize that the combined approach of MM and DSC yields unique information that can correlate the various Tm-profiles seen in the Tm-diagram with the structural variation of mixed-chain lipids as caused by the introduction of different numbers/positions of methylene-interrupted cis-double bonds.

Effect of ionic and nonionic contrast media on fibrinolysis in patients undergoing angiocardiography

Very few investigators have studied the effect of contrast media on fibrinolysis. The results of those previous studies are contradictory and inconclusive. The purpose of this study was to evaluate the effect of ionic and nonionic contrast media on fibrinolysis in patients undergoing angiocardiography. Sixty-two patients randomly received either ionic contrast medium Hypaque-76 (n = 31) or nonionic contrast medium Ultravist-370 (n = 31). Plasma tissue plasminogen activator (t-PA), plasminogen activator inhibitor 1 (PAI-1), fibrinogen, and D-dimer were measured before and 20 minutes after the procedures. A significant increase of PAI-1 levels was seen in the Ultravist group but not in the Hypaque group. The t-PA and fibrinogen levels remained virtually unchanged in both groups. A significant increase of D-dimer concentrations was observed in the Hypaque group but not in the Ultravist group. The results of this study may in part explain the reason that the ionic contrast media produce fewer thromboembolic complications than the nonionic contrast media during the cardiac catheterization.

N-cyanoimidazole and diimidazole imine: water-soluble condensing agents for the formation of the phosphodiester bond

The reaction of BrCN with imidazole results in the formation of N-cyanoimidazole and diimidazole imine. These compounds were shown to be useful condensing agents for the formation of the phosphodiester bound in aqueous solution.

Characteristics of patients with Burkholderia cepacia bacteremia

Burkholderia cepacia has become an important pathogen of infections in immunocompromised and nosocomial patients. The characteristics of 42 episodes of B. cepacia bacteremia in 40 patients admitted to the Taipei Veterans General Hospital between January 1997 and December 1999 were retrospectively analyzed. Factors that adversely influenced the mortality rate included respiratory failure, an unknown infection source, a period in an intensive care unit, and shock. Most of the patients had serious underlying diseases, such as diabetes mellitus, malignancy, congestive heart failure, and chronic obstructive pulmonary disease. The mean time for a positive blood culture was 45 days after admission. The overall mortality rate was 28.6% (12/42), and 44.4% (12/27) of all deaths were directly related to B. cepacia bacteremia. Polymicrobial bacteremia was found in 5 patients. Ceftazidime was the most effective antimicrobial agent in vitro, whereas chloramphenicol, imipenem, and trimethoprim/sulfamethoxazole were less effective alternatives. Appropriate antibiotic therapy was given to 30 patients, most of whom responded to the therapy except for 5 who died despite receiving appropriate treatment. Although B. cepacia infection develops in a relatively small proportion of hospitalized individuals, it has a major impact on morbidity and mortality. In view of the fact that B. cepacia develops resistance to a wide range of antimicrobial agents, ceftazidime and/or trimethoprim/sulfamethoxazole should be the drug of choice for empiric therapy.

Ambulance utilization in metropolitan and rural areas in Taiwan

BACKGROUND AND PURPOSE

Emergency medical services (EMS) have expanded rapidly in the Asian developing countries recently. However, the patterns of ambulance utilization in the rural and urban areas of these countries have not been thoroughly described. This study investigated the patterns of ambulance utilization in two urban areas and the larger rural area of Taiwan formerly designated Taiwan Province.

METHODS

We studied a total of 304,368 ambulance missions during 1997 in Taiwan. We analyzed the differences in the characteristics of emergency calls and the interventions performed on the scene in two urban areas, Taipei City and Kaohsiung City, and in the rural area formerly designated Taiwan Province.

RESULTS

The call volume and percentage of non-transport calls were higher in the more developed of the two urban areas, Taipei City, than in Kaohsiung (p < 0.01). The incidence of calls with trauma-related causes was higher in both urban areas. However, the percentage of calls placed for trauma-related reasons was higher in the rural area (p < 0.01). More calls for acute medical illness were placed in Taipei City (p < 0.01) than in the rural area. The number of interventions performed by ambulance staff was higher in Taipei City and Kaohsiung City than in the rural area (p < 0.01). The availability of acute illness management was generally lower than needed in all areas.

CONCLUSIONS

Call volume and the number of interventions performed were higher in the urban area, whereas the percentage of trauma-related calls was higher in the rural area. These findings suggest that EMS use patterns in Taiwan are transitioning towards a pattern characteristic of a more developed country. The differences in ambulance utilization patterns must be considered in plans to further develop EMS services in these areas.

Induction of disabled-2 gene during megakaryocyte differentiation of k562 cells

Megakaryocyte differentiation is often accompanied by the changes of gene expression pattern. Here we reported that the expression of DAB2, a putative adaptor protein in cell signaling, was induced at the protein and mRNA levels upon 12-O-tetradecanoylphorbol-13-acetate-mediated megakaryocyte differentiation of human chronic myeloid leukemic K562 cells. On the other hand, the differentiation agents DMSO and retinoic acid had no effect on DAB2 expression. Analysis of promoter activity with the human DAB2 luciferase reporter constructs suggested that the regulation is partially at the transcriptional level. The responsive sequences located within an 80-bp DAB2 promoter region. To determine the involvement of MEK1-p42/p44 MAPK pathway in mediating DAB2 gene expression, we have performed the following experiments and found that (i) there was sustained activation of p42/p44 MAPK, but not p38 MAPK, upon K562 cells differentiation; (ii) application of MEK1 inhibitor U0126 reduced the expression of DAB2 protein, mRNA and promoter activity, as well as cell differentiation; (iii) constitutively active MEK1 increased DAB2 promoter activity; and (iv) dominant negative ERK2 abolished constitutively active MEK1-induced DAB2 promoter activity. Taken together, our results indicate that DAB2 gene is induced upon megakaryocyte differentiation by the MEK1-p42/p44 MAPK pathway and may define a new role of DAB2 in hematopoietic cell differentiation.

Statistical analysis of QT interval as a function of changes in RR interval in the conscious dog

INTRODUCTION

The duration of cardiac ventricular depolarization and repolarization is represented as the QT interval. QT prolongation has been associated with the occurrence of arrhythmias. Both cardiovascular as well as noncardiovascular agents have caused QT prolongation and sudden death in humans. Changes in heart rate (HR) play a major, though not exclusive, role in QT variation. Considerable debate has centered on how to normalize QT for variations in HR (QTc).

METHODS

The most common approaches use Bazett's (QTc = QT/(square root)RR) or Fridericia's (QTc = QT/(cube root)) formulas to fit the data and establish a single coefficient to analyze QT with respect to its relationship to RR, where RR= 60/HR. These single-coefficient models do not adequately describe the QT functional relationship with RR for the dog. Therefore, any calculation of QTc for the dog is misleading and can result in a false-positive indication or mask the potential hazards of a high QT. Other investigators have proposed multicoefficient exponential regression analyses to best fit the QT-RR relationship.

RESULTS AND DISCUSSION

Data presented here from dogs under resting conditions and during pharmacological maneuvers (E-4031 or cisapride intravenous infusion) support the use of such a model. In order to fully characterize drug-induced changes in the QT-RR relationship, our approach includes a statistical comparison of the regression curves for an overall effect, and quantitates the incidence and magnitude of points exceeding the upper 95% confidence interval ('outliers') to assess the degree of heterogeneity of ventricular repolarization.

Vibration characteristics of composite piezoceramic plates at resonant frequencies: experiments and numerical calculations

The experimental measurement of the resonant frequencies for the piezoceramic material is generally performed by impedance analysis. In this paper, we employ an optical interferometry method called the amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) to investigate the vibration characteristics of piezoceramic/aluminum laminated plates. The AF-ESPI is a powerful tool for the full-field, noncontact, and real-time measurement method of surface displacement for vibrating bodies. As compared with the conventional film recording and optical reconstruction procedures used for holographic interferometry, the interferometric fringes of AF-ESPI are produced instantly by a video recording system. Because the clear fringe patterns measured by the AF-ESPI method will be shown only at resonant frequencies, both the resonant frequencies and corresponding vibration mode shapes are obtained experimentally at the same time. Excellent quality of the interferometric fringe patterns for both the in-plane and out-of-plane vibration mode shapes are demonstrated. Two different configurations of piezoceramic/aluminum laminated plates, which exhibit different vibration characteristics because of the polarization direction, are investigated in detail. From experimental results, we find that some of the out-of-plane vibration modes (Type A) with lower resonant frequencies cannot be measured by the impedance analysis; however, all of the vibration modes of piezoceramic/aluminum laminated plates can be obtained by the AF-ESPI method. Finally, the numerical finite element calculations are also performed, and the results are compared with the experimental measurements. Excellent agreements of the resonant frequencies and mode shapes are obtained for both results.

Collection efficiency and capacity of three samplers for acidic and basic gases

This paper compares the collection efficiency and capacity of a coated porous metal disk with those of a silica gel tube and an impinger at the acid or basic aerosol concentration of two times the permissible exposure limitation (Taiwan IOSH, Institute of Occupational Safety and Health), relative humidity of 80 +/- 5%, and temperature of 30 +/- 3 degrees C in the laboratory. Using 5% sodium carbonate/glycerin coating, the collection efficiencies of the porous metal disk for nitric acid, hydrogen chloride, and hydrogen fluoride are found to be higher than those of the silica gel tube and the impinger when the sampling time is less than 3.0 h. The gas collection capacity of the porous metal disk coated with 5% sodium carbonate is calculated to be 3.9, 5.8, and >2.5 mg for nitric acid, hydrogen chloride, and hydrogen fluoride, respectively. For ammonia, the porous metal disk coated using 4% citric acid performs slightly better than the impinger, and the corresponding capacity is slightly greater than 33.6 mg.

Hand-assisted laparoscopic radical nephrectomy of renal cell carcinoma--a case report

A 62-year-old female patient with chronic medical history of DM and hypertension was admitted due to traffic accident. She was asymptomatic until 5 days before admission. She was referred to our medical center with an abdominal CT revealing left renal tumor. The diameter of the renal mass was 50 mm. On ultrasonographic examination, a heterogenous lesion over the left kidney was noted. Renal scanning showed a cold nodule in the left kidney. Hand-assisted laparoscopic transperitoneal radical nephrectomy was performed smoothly. The kidney was removed from the hand port in the supraumbilical skin incision with a volume of 14 x 7 x 6 cm3 and weight of 570 gm. The operation time was 5 hours, blood loss was 200 cc, and no significant change of blood pressure was noted during the surgery. The patient's postoperative course was uneventful. The pathological report of this mass was renal cell carcinoma.

Experimental and numerical investigations of resonant vibration characteristics for piezoceramic plates

Electronic speckle pattern interferometry (ESPI) is a full field, non-contact technique for measuring the surface displacement of a structure subjected to static loading or, especially, to dynamic vibration. In this article we employ an optical system called the amplitude-fluctuation ESPI with out-of-plane and in-plane measurements to investigate the vibration characteristics of piezoceramic plates. Two different configurations of piezoceramic plates, namely the rectangular and the circular plates, are discussed in detail. As compared with the film recording and optical reconstruction procedures used for holographic interferometry, the interferometric fringes of AF-ESPI are produced instantly by a video recording system. Because the clear fringe patterns will be shown only at resonant frequencies, both the resonant frequencies and the corresponding mode shapes are obtained experimentally at the same time by the proposed AF-ESPI method. Excellent quality of the interferometric fringe patterns for both the in-plane and out-of-plane vibration mode shapes is demonstrated. The resonant frequencies of the piezoceramic plates are also measured by the conventional impedance analysis. From experimental results, we find that the out-of-plane vibration modes (type A) with lower resonant frequencies cannot be measured by the impedance analysis and only the in-plane vibration modes (type B) will be shown. However, both the out-of-plane (bending) and in-plane (extensional) vibration modes of piezoceramic plates are obtained by the AF-ESPI method. Finally, the numerical finite element calculations are also performed, and the results are compared with the experimental measurements. It is shown that the numerical calculations and the experimental results agree fairly well for both the resonant frequencies and the mode shapes.

Structure activity studies on group C meningococcal polysaccharide-protein conjugate vaccines: effect of O-acetylation on the nature of the protective epitope

A series of group C meningococcal polysaccharide-tetanus toxoid (GCMP-TT) conjugates were prepared as vaccines with varying percentages of O-acetylation at the C-7 and C-8 positions of sialic acid residues in the polysaccharide (PS). The immune response in mice was highly dependent on the degree of O-acetylation. Less O-acetylation resulted in higher serum bactericidal activity (SBA) towards the O-acetylated (OA) meningococcal strain, C11. In addition, since an unconjugated de-O-acetylated (dOA) GCMP vaccine was previously shown to be highly immunogenic in humans, we had chosen this dOA form to couple with TT by reductive amination for clinical evaluation. This conjugate vaccine was shown to be well-tolerated and highly immunogenic in adults, children, and infants in the UK. To understand the nature of the GCMP protective epitope, a series of spectroscopic and serological studies were conducted, using high resolution H-NMR spectroscopy at 500 MHz and competitive inhibition SBA assays. The dOA GCMP was 10-1000 times better at inhibiting the SBA for an OA strain than the OA GCMP, suggesting that the GCMP-based protective epitope on the bacterium exists in a dOA form. In addition, SBA for an OA strain is highly correlated with dOA GCMP-specific IgG. NMR data on freshly isolated GCMP indicated that, on the surface of the organism, most of the O-acetylation exists at position C-8, with some regions containing dOA or OA C-7 sialic acid. After extraction of PS and storage in solution, most of the O-acetyl groups migrate to C-7, leaving an epitope that is conformationally related, but not quite identical (due to the presence of the O-acetyl group), to the one contained in the dOA PS. We speculate that the role of the O-acetyl group at the C-8 position of the PS on the organism is to form less immunogenic epitopes, or mask the protective epitope, and thus escape immune surveillance. The dOA form of the vaccine may therefore provide better protection against group C meningococcal disease than the OA form by eliciting a greater proportion of functional antibodies that are directly aimed at the protective epitope.