Tissue expression of gelsolin in oral carcinogenesis progression and its clinicopathological implications

Gelsolin has important cellular functions, including cell motility, proliferation and apoptosis. Altered gelsolin expression has been reported in several types of human malignancies, but has not been evaluated in oral carcinogenesis. In this study, all normal oral mucosa (n=12) had high gelsolin expression, whereas only 7.7% of oral precancerous lesions (n=26) had positive gelsolin expression. A significant increased positive staining was found in primary (n=51; 37.3%) and metastatic (n=26; 30.8%) oral squamous cell carcinoma lesions. Tumors with high gelsolin expression were associated with greater tumour size (P=0.007), invasive growth (P=0.02), and younger age (P=0.006). High gelsolin expression conferred a poor clinical outcome in patients with metastatic disease (P=0.005). In conclusion, a biphasic profile in gelsolin expression was observed during the progression of oral carcinogenesis. This may be due to a balance of its multiple cellular functions in tumour invasion and cell growth. The underlying mechanisms, however, remain to be elucidated.

Pre-operative chemo-radiotherapy improves the sphincter preservation rate in patients with rectal cancer located within 3 cm of the anal verge

AIMS

To evaluate whether pre-operative chemo-radiotherapy (CRT) improves the sphincter preservation rate for distal rectal cancers within 3 cm of the anal verge.

METHODS

Between January 2001 and December 2004, 49 patients underwent surgery with or without pre-operative CRT for primary rectal adenocarcinoma within 3 cm of the anal verge. Clinical data were retrospectively reviewed, including stage workups, surgical records and pathology records to determine sphincter preservation rate and the factors influencing sphincter preservation.

RESULTS

Of 49 patients with rectal tumours within 3 cm of the anal verge, 31 underwent pre-operative CRT followed by surgery (CRT group), and 18 underwent surgery alone (non-CRT group). Sphincter preservation was possible in 11 of 31 CRT patients, and only one of 18 non-CRT patients (p=0.036). The factors most influencing sphincter preservation were reduction in tumour size (p=0.005) and downstaging (p=0.001) following pre-operative CRT.

CONCLUSION

We could observe that sphincter preservation was improved in CRT group with statistical significance when compared to non-CRT group in our study patients with rectal cancer within 3 cm of the anal verge.

Comparative study of the subserosal versus submucosal dye injection method for sentinel node biopsy in gastric cancer

AIMS

To determine the most efficient injection method for a sentinel node (SN) biopsy in gastric cancer.

METHODS

Gastric adenocarcinoma patients without serosal invasion and distant metastasis were prospectively enrolled in this study. Isosulfan blue was injected into the subserosa (SS) of the first set of 71 consecutive patients and an intraoperative endoscopic submucosal (SM) injection of the same dye was injected into the second set of 50 consecutive patients. After the biopsy of blue-stained SNs, a gastrectomy with a D2 lymphadenectomy was performed. All dissected lymph nodes were evaluated for metastasis. The results of the SN biopsies were compared between the SS and SM dye injection methods.

RESULTS

Detection rate (0.92 vs 0.94), mean number of SNs (2.5 vs 2.9) and sensitivity (0.61 vs 0.46) of the SN biopsies were not significantly different between the SS and SM injection methods (P>0.05). The operation time was significantly shorter in the SS than the SM injection method (159.7 vs 172.7 min, P=0.030).

CONCLUSIONS

Both injection methods were equally efficient in their roles for a SN biopsy in gastric cancer. However, the SS injection method was more preferable due to its easy technique and short operation time.

Tuberculin reactivity in adults after 50 years of universal bacille Calmette–Guérin vaccination in Taiwan

We aimed to assess whether tuberculin reactivity in adults is affected by bacille Calmette-Guerin (BCG) vaccination after 50 years of universal BCG vaccination with 80-95% coverage. A community-based study on tuberculin reactivity in 619 participants was conducted in February 2000 in Keelung city, Taiwan. Information on BCG vaccination policies and annual risk of infection (ARI) in the underlying population was extracted from consecutive national prevalence surveys relating to the period 1952-1997. Compared with the expected ARI estimate, the standardized morbidity ratio of positive tuberculin response for vaccination in infancy was 2.2 (95% CI 0.3-15.5) for those aged <10 years. The corresponding figures for older age groups ranged from 3.6 (95% CI 2.2-5.9) for those aged 10-12 years to 0.7 (95% CI 0.5-0.9) for those aged 57-67 years. This suggests that the effect of BCG vaccination on positive tuberculin response in adults aged >30 years is probably negligible irrespective of age at vaccination or revaccination and that the tuberculin skin test can be used to diagnose TB in control programmes in countries with moderate or high incidence of TB.

Enhanced optical nonlinearity near the photonic bandgap edges of a cholesteric liquid crystal

The third-order Kerr nonlinear optical effect of a one-dimensional photonic bandgap structure of a cholesteric liquid crystal is investigated. In a femtosecond nonlinear transmission measurement, nonlinear optical changes in the bandgap edges are observed. From analysis of the dispersion relation, Kerr nonlinear coefficients of nematics, forming the cholesteric liquid crystal, are found to be enhanced by 1-2 orders of magnitude through the photonic bandgap structure.

Mechanism of bradykinin-induced Ca(2+) mobilization in MG63 human osteosarcoma cells

BACKGROUND

The effect of bradykinin on intracellular free Ca(2+) levels ([Ca(2+)](i)) in MG63 human osteosarcoma cells was explored using fura-2 as a Ca(2+) dye.

METHODS/RESULTS

Bradykinin (0.1 nM-1 microM) increased [Ca(2+)](i) in a concentration-dependent manner with an EC(50) value of 0.5 nM. The [Ca(2+)](i) signal comprised an initial peak and a fast decay which returned to baseline in 2 min. Extracellular Ca(2+) removal inhibited the peak [Ca(2+)](i )signals by 35 +/- 3%. Bradykinin (1 nM) failed to increase [Ca(2+)](i) in the absence of extracellular Ca(2+ )after cells were pretreated with thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor; 1 microM). Bradykinin (1 nM)-induced intracellular Ca(2+) release was nearly abolished by inhibiting phospholipase C with 2 microM 1-(6-((17 beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122). The [Ca(2+)](i )increase induced by 1 nM bradykinin in Ca(2+)- free medium was abolished by 1 nM HOE 140 (a B2 bradykinin receptor antagonist) but was not altered by 100 nM Des-Arg-HOE 140 (a B1 bradykinin receptor antagonist). Pretreatment with 1 pM pertussis toxin for 5 h in Ca(2+) medium inhibited 30 +/- 3% of 1 nM bradykinin-induced peak [Ca(2+)](i) increase.

CONCLUSIONS

Together, this study shows that bradykinin induced [Ca(2+)](i) increases in a concentration-dependent manner, by stimulating B2 bradykinin receptors leading to mobilization of Ca(2+) from the thapsigargin-sensitive stores in a manner dependent on inositol-1,4,5-trisphosphate, and also by inducing extracellular Ca(2+) influx. The bradykinin response was partly coupled to a pertussis toxin-sensitive G protein pathway.

Effect of nordihydroguaiaretic acid on intracellular Ca(2+) concentrations in C6 glioma cells

The effect of nordihydroguaiaretic acid (NDGA) on Ca(2+) signaling in C6 glioma cells has been investigated. NDGA (5-100 microM) increased [Ca(2+)]i concentration-dependently. The [Ca(2+)]i increase comprised an initial rise and an elevated phase over a time period of 4 min. Removal of extracellular Ca(2+) reduced NDGA-induced [Ca(2+)]i signals by 52+/-2%. After incubation of cells with NDGA in Ca(2+)-free medium for 4 min, addition of 3 mM CaCl2 induced a concentration-dependent increase in [Ca(2+)]i. NDGA (100 microM)-induced [Ca(2+)]i increases in Ca(2+)-containing medium was not changed by pretreatment with 10 microM nifedipine or verapamil. In Ca(2+)-free medium, pretreatment with the endoplasmic reticulum Ca(2+) pump inhibitor thapsigargin (1 microM) abolished 100 microM NDGA-induced [Ca(2+)]i increases. Inhibition of phospholipase C with 2 microM U73122 had little effect on 100 microM NDGA-induced Ca(2+) release. Several other lipoxygenase inhibitors had no effect on basal [Ca(2+)]i. Collectively, the results suggest that NDGA increased [Ca(2+)]i in glioma cells in a lipoxygenase-independent manner, by releasing Ca(2+) from the endoplasmic reticulum in a manner independent of phospholipase C activity and by causing Ca(2+) influx.

Nordihydroguaiaretic acid elevates osteoblastic intracellular Ca2+

Nordihydroguaiaretic acid (NDGA) is widely used as a pharmacological tool to inhibit lipoxygenases; however, recent evidence suggests that it increases renal intracellular [Ca2+]i via novel mechanisms. Here the effect of NDGA on Ca2+ signaling in MG63 osteoblastic cells was explored using fura-2 as a Ca2+ indicator. NDGA (2-50 microM) increased [Ca2+]i in a concentration-dependent manner. The signal comprised an initial rise and an elevated phase over a time period of 4 min. Removing extracellular Ca2+ reduced 2-50 microM NDGA-induced signals by 62+/-2%. After incubation with 50 microM NDGA in Ca2+-free medium for several minutes, addition of 3 mM CaCl2 induced an increase in [Ca2+]i. NDGA (50 microM)-induced [Ca2+]i increases were not changed by pretreatment with 10 microM of verapamil, diltiazem, nifedipine, nimodipine and nicardipine. In Ca2+-free medium, pretreatment with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin (1 microM) inhibited 50 microM NDGA-induced [Ca2+]i increases by 69+/-3%. Inhibition of phospholipase C with 2 microM U73122 had little effect on 50 microM NDGA-induced Ca2+ release. Several other lipoxygenase inhibitors had no effect on basal [Ca2+]i. At a concentration that did not increase basal [Ca2+]i, NDGA (1 microM) did not alter 10 microM ATP- or 1 microM thapsigargin-induced [Ca2+]i increases. Alteration of protein kinase C activity with 1 nM phorbol 12-myristate 13-acetate or 2 microM GF 109203X did not affect 50 microM NDGA-induced [Ca2+]i increases. Together, the results show that NDGA increased [Ca2+]i in osteoblasts in a lipoxygenase-independent manner, by releasing stored Ca2+ in a fashion independent of phospholipase C activity, and by causing Ca2+ influx.

Crystallization and preliminary crystallographic results of apo and complex forms of human dehydroepiandrosterone sulfotransferase

Dehydroepiandrosterone sulfotransferase converts dehydroepiandrosterone (DHEA) and some other steroids to their sulfonated forms. The human enzyme has been crystallized in the presence of substrate (DHEA) alone, in the presence of substrate and non-sulfated cofactor analogue (PAP) and in the absence of both substrate and PAP in our laboratory, with data sets collected at a synchrotron source. The crystals of the uncomplexed form belong to the orthorhombic space group C222(1), with unit-cell parameters a = 85.26, b = 87.69, c = 108.20 A and data 99.2% complete to 2.35 A resolution. The DHEA complex crystallizes in the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 74.46, b = 127.49, c = 44.59 A and data 92.9% complete to 2.15 A resolution. The ternary complex crystallizes in the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 62.25, b = 87.28, c = 138.86 A and data 98.6% complete to 2.50 A resolution. Preliminary molecular-replacement solutions indicate significant variations in dimer formation.

Critical residues for the specificity of cofactors and substrates in human estrogenic 17beta-hydroxysteroid dehydrogenase 1: variants designed from the three-dimensional structure of the enzyme

Human estrogenic 17beta-hydroxysteroid dehydrogenase is an NADP(H)-preferring enzyme. It possesses 11- and 4-fold higher specificity toward NADP(H) over NAD(H) for oxidation and reduction, respectively, as demonstrated by kinetic studies. To elucidate the roles of the amino acids involved in cofactor specificity, we generated variants by site-directed mutagenesis. The results showed that introducing a positively charged residue, lysine, at the Ser12 position increased the enzyme's preference for NADP(H) more than 20-fold. Substitution of the negatively charged residue, aspartic acid, into the Leu36 position switched the enzyme's cofactor preference from NADPH to NAD with a 220-fold change in the ratio of the specificity toward the two cofactors in the case of oxidation. This variant dramatically abolished the enzyme's reductase function and stimulated its dehydrogenase activity, as shown by enzyme activity in intact cells. The substrate-binding pocket was also studied with four variants: Ser142Gly, Ser142Cys, His221Ala, and Glu282Ala. The Ser142Gly variant abolished most of the enzyme's oxidation and reduction activities. The residual reductase activity in vitro is less than 2% that of the wild-type enzyme. However, the Ser142Cys variant was fully inactive, both as a partially purified protein and in intact cells. This suggests that the bulky sulfhydryl group of cysteine entirely disrupted the catalytic triad and that the Ser142 side chain is important for maintaining the integrity of this triad. His221 variation weakened the apparent affinity for estrone, as demonstrated by a 30-fold increase in Michaelis-Menten constant, supporting its important role in substrate binding. This residue may play an important role in substrate inhibition via the formation of a dead-end complex. The formerly suggested importance of Glu282 could not be confirmed.

Mechanisms of diethylstilbestrol-induced calcium movement in MG63 human osteosarcoma cells

The effect of the estrogen diethylstilbestrol (DES) on cytosolic free Ca(2+) levels ([Ca(2+)](i)) in MG63 human osteoblasts was explored by using fura-2 as a Ca(2+) indicator. DES at concentrations between 5--20 microM induced an immediate increase in [Ca(2+)](i) in a concentration-dependent manner with an EC(50) of 10 microM. Removing extracellular Ca(2+) reduced the Ca(2+) signal by 70%. Pretreatment with 50 microM La(3+) or 10 microM of nifedipine, verapamil and diltiazem did not change 20 microM DES-induced [Ca(2+)](i) increases. Addition of 3 mM Ca(2+) increased [Ca(2+)](i) in cells pretreated with 20 microM DES in Ca(2+)-free medium. Pretreatment with 1 microM thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor) to deplete the endoplasmic reticulum Ca(2+) store partly inhibited 20 microM DES-induced Ca(2+) release, but addition of carbonylcyanide m-chlorophenylhydrazone (CCCP; a mitochondrial uncoupler) and thapsigargin together abolished DES-induced Ca(2+) release. Conversely, pretreatment with 20 microM DES abrogated CCCP- and thapsigargin-induced Ca(2+) release. Inhibition of phospholipase C activity with 2 microM U73122 did not alter 20 microM DES-induced Ca2+ release. Another estrogen 17beta-estradiol also increased [Ca(2+)](i) in a concentration-dependent manner with an EC50 of 7 microM. Together, the data indicate that in human osteoblasts, DES increased [Ca(2+)](i) via causing Ca(2+) release from both mitochondria and the endoplasmic reticulum in a phospholipase C-independent manner, and by causing Ca(2+) influx.

Acute and long-term outcomes of stenting in coronary vessel > 3.0 mm, 3.0-2.5 mm, and < 2.5 mm

We compared the acute and long-term outcomes of stentings in coronary vessels > 3.0 mm, 3.0-2.5 mm, and < 2.5 mm. A total of 1,152 patients underwent coronary stenting was divided into three groups based on the reference vessel size. Group A consisted of 598 patients (667 lesions) with a reference vessel diameter > 3.0 mm, group B 485 patients (544 lesions) with a reference vessel diameter of 3.0-2.5 mm, and group C 114 patients (119 lesions) with a reference vessel diameter < 2.5 mm. The procedural success, stent thrombosis, and in-hospital cardiac event rate were similar in the three groups. At 6-month angiographic follow-up, the lesion restenotic rate was significantly higher in the small-vessel group (14%, 22%, and 26% in groups A, B, and C, respectively; P = 0.011). These differences appeared to result from a lesser acute gain and a lesser net gain in small-vessel group; the late luminal loss was similar in the three groups. During a follow-up duration of 28 +/- 3 months, group C patients had a significantly lower rate of event-free survival than the group A and B patients (71% vs. 85% and 82%; P = 0.002). Stepwise regression analysis demonstrated that complex lesion (P = 0.032) and long lesion (P = 0.046) are independent predictors of restenosis in very-small-vessel (< 2.5 mm) stenting. In conclusion, the acute results of stenting in small coronary arteries appear safe and feasible with a high procedural success rate and a low incidence of stent thrombosis. Stenting in patients with a small coronary artery appears to have a similar in-hospital cardiac event rate, but a higher angiographic restenosis rate and a lower event-free survival rate, compared to stenting in patients with a larger coronary artery. The predictors of restenosis in very-small-vessel stenting are complex lesions and long lesions. Cathet Cardiovasc Intervent 2001;53:314-322.

Solution structure, backbone dynamics, and stability of a double mutant single-chain monellin. structural origin of sweetness

Single-chain monellin (SCM), which is an engineered 94-residue polypeptide, has been characterized as being as sweet as native two-chain monellin. Data from gel-filtration high performance liquid chromatography and NMR has proven that SCM exists as a monomer in aqueous solution. In order to determine the structural origin of the taste of sweetness, we engineered several mutant SCM proteins by mutating Glu(2), Asp(7), and Arg(39) residues, which are responsible for sweetness. In this study, we present the solution structure, backbone dynamics, and stability of mutant SCM proteins using circular dichroism, fluorescence, and NMR spectroscopy. Based on the NMR data, a stable alpha-helix and five-stranded antiparallel beta-sheet were identified for double mutant SCM. Strands beta1 and beta2 are connected by a small bulge, and the disruption of the first beta-strand were observed with SCM(DR) comprising residues of Ile(38)-Cys(41). The dynamical and folding characteristics from circular dichroism, fluorescence, and backbone dynamics studies revealed that both wild type and mutant proteins showed distinct dynamical as well as stability differences, suggesting the important role of mutated residues in the sweet taste of SCM. Our results will provide an insight into the structural origin of sweet taste as well as the mutational effect in the stability of the engineered sweet protein SCM.

Human dehydroepiandrosterone sulfotransferase: purification and characterization of a recombinant protein

Dehydroepiandrosterone sulfate is the most abundant sulfated steroid transformed in human tissues and serves as a precursor for steroid hormones. Recombinant human dehydroepiandrosterone sulfotransferase (DHEA-ST) expressed in glutathione sulfotransferase fusion form in E. coli was purified using glutathione sepharose 4B affinity adsorption chromatography, a Factor Xa cleavage step, and Q-sepharose fast flow column chromatography. The homogeneous preparation had an activity toward dehydroepiandrosterone (DHEA) of 150+/-40 nmol/min per mg of protein under the assay conditions at an overall yield of 38.4%. The recombinant human DHEA-ST was shown to have a subunit mass of 34 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis, while having a molecular mass of 67.2 kDa by Superose-12 gel filtration. Our results indicate that the active recombinant enzyme expressed in E. coli is a homodimer.Biochemical properties for purified DHEA-ST were studied using DHEA as a substrate. The optimum pH ranged from pH 7 to 8, and the optimum temperature 40-45 degrees C. Ninety percent of basal DHEA-ST activity remained even after the enzyme was treated at 45 degrees C for 15 min. The 50% inactivation concentration of NaCl for DHEA-ST activity was determined to be around 500 mM. The K(m) value for DHEA was 1.9+/-0.3 microM and V(max)=190+/-18 nmol/min per mg of protein at 37 degrees C, pH 7.5.

Benefits of late coronary artery stenting in patients with acute myocardial infarction with and without thrombolytic therapy

BACKGROUND

There are no added benefits when balloon angioplasty is conducted in conjunction with thrombolytic therapy in patients with acute myocardial infarction. The purpose of this study was to determine whether or not thrombolysis has an impact on the outcome of late coronary artery stenting following acute myocardial infarction.

METHODS

The outcome of late coronary artery stenting in the infarct-related artery following acute infarction was compared in patients with (68 patients, group A) and without (118 patients, group B) prior thrombolytic therapy.

RESULTS

The baseline characteristics were similar in the 2 groups except that total occlusion of the infarct-related artery was more common in group B. The angiographic characteristics of the target lesion were similar in the 2 groups; the procedural success rate was 98% in both groups. There was no subacute thrombosis or other complications in either group. The 6-month follow-up coronary angiography and the restenosis rate was 18% in both groups; the reocclusion rate was 2% in group A and 4% in group B. The increment of the left ventricular ejection fraction was similar in both groups (6% versus 7%). During a follow-up duration of 18 +/- 3 months, the mortality rate was 3% versus 2%, reinfarction 0% versus 1%, recurrent angina 6% versus 4%, and target lesion revascularization by angioplasty 13% versus 13% in group A and B patients, respectively.

CONCLUSION

The outcome of late coronary artery stenting following acute myocardial infarction in patients with and without prior thrombolytic therapy was comparable. Significant improvement of left ventricular function was noted in both groups.

Clinical significance of hepatitis C virus infection to alcoholics with cirrhosis in Korea

BACKGROUND/METHODS

To investigate the prevalence and clinical significance of hepatitis C virus (HCV) infection and its relationship with the development of hepatocellular carcinoma (HCC), 162 consecutive alcoholic patients with cirrhosis were studied. Alcohol intake and parenteral risk factors were investigated by interview using a questionnaire. All patients had consumed at least 80 g alcohol/day for at least the past 5 years. Sera were tested for anti-HCV using a third-generation enzyme immunoassay (EIA), hepatitis B s antigen (HBsAg), anti-HBs, anti-HBc and anti-HIV. Serum HCV-RNA was detected by a one-tube reverse transcription-polymerase chain reaction (RT-PCR) method. Patients were classified into three groups accroding to the presence or absence of viral markers: (i) cases without anti-HCV or HBsAg (group A); (ii) cases with HBsAg only (group B); and (iii) cases with anti-HCV only (group C). Demographic and clinical findings were compared among the three groups.

RESULTS

Anti-HCV was present in 17 cases (10.5%) and HBsAg was present in 47 cases (29%). No patient had both anti-HCV and HBsAg. Group C subjects were the oldest, but the duration of drinking in this group was similar to that of group A. There was no significant difference in the daily alcohol intake among the three groups. Previous surgical operations and tattooing were more frequent in group C. Only one patient in group C was an intravenous drug user. The combined rate of HCC was significantly higher in groups B and C than in groups A (34, 23.5 and 6.1%, respectively). Laboratory data showed a higher platelet count, higher albumin level, lower bilirubin level and lower aspartate aminotransferase/alanine aminotransferase ratio in group C patients than in the other two groups. Hepatitis C virus RNA was detected in 14 of 85 cases tested (16.5%), in 11 of 12 cases (91.7%) with anti-HCV and in three of 73 cases (4.1%) without anti-HCV.

CONCLUSIONS

Hepatitis C virus infection is frequent in alcoholic patients with cirrhosis in Korea. Hepatitis C virus, as well as hepatitis B virus, infection may have a synergistic effect on the development of HCC in alcoholic patients.

Evaluation of a population-based screening for type 2 diabetes: a community-based screening project in Puli, Taiwan

BACKGROUND

A Markov method incorporating the relationships between prevalence, incidence, and mortality with respect to type 2 diabetes was used to assess a population-based screening for this disease.

METHODS

Data from a population-based screening project for residents of Puli, Taiwan, over 30 years of age (n= 1,219) were used to estimate the annual incidence of asymptomatic type 2 diabetes, the prevalence to incidence (P/I) ratio, and the hazard rate of death due to type 2 diabetes. These parameters were employed to develop a Markov process to evaluate the effects of early detection of type 2 diabetes on the risk of death from this disease in a simulated population (n= 10,000) receiving biennial, 5-year interval, or no screening.

RESULTS

The estimated annual incidence, average duration from asymptomatic to symptomatic type 2 diabetes (P/I ratio), and hazard rate for death from this disease were 0.86% (95% CI 0.50-1.48), 10 years (95% CI 7.69-14.01), and 1.1% per year, respectively. This yields an optimal screening interval of 5 years. Simulation of a 5-year interval screening regimen versus no screen ing yielded a relative risk reduction of 31% (95% CI 12-46%). A similar value was found for a biennial screening regime.

CONCLUSIONS

The results suggest that early detection of type 2 diabetes via a community-based screening project in developing countries with high prevalence is worthwhile.

Time trend of substance use among adolescent students in Taiwan, 1991-1996

The purpose of this study was to determine the prevalence and time trend of cigarette, alcohol, and illicit substance use among adolescent students in Taiwan, from 1991 through 1996. Subjects were selected through a two-stage random-sampling procedure. In the first stage, the strata were based on the type of school: middle school (13-15 years), high school (16-18), vocational school (16-18), and junior college (first 3 years only, 16-18). In the second stage, the strata were based on grade: one class each for 1st, 2nd, and 3rd grades were randomly selected from each type of school. Students were guaranteed anonymity before the questionnaire was administered. About 12,000 students from 100 schools participated each year in 1991 and 1994-1996. In 1993, 8,320 students from 65 schools participated. The prevalence of smoking and drinking decreased between 1991 and 1994, and then increased between 1994 and 1996. In 1996, the prevalence of illicit substance use was 15.4% for smoking, 16.7% for drinking, and 1.5% for illicit substance use. The rate of illicit substance use was lowest among high school students, followed by middle school students, and higher among students in vocational schools and junior colleges. The percentage of smokers and drinkers who had started early (at age 12 or earlier) rose every year. The prevalence of smoking and drinking habits among girls increased consistently during the study period. The most commonly abused substance was amphetamine. However, in 1996, sniffing glue became more prominent among middle school students, and flunitrazepam became the second most commonly abused substance among high school students.

Clinical and angiographic outcomes are similar with half, single, or multiple contiguous Palmaz-Schatz stent implantations for a single coronary stenosis

We compared the immediate and 6-month clinical and angiographic outcomes in patients undergoing a half, a single, or multiple contiguous stent implantations for a single coronary stenosis. Four hundred forty-three consecutive patients, who underwent elective Palmaz-Schatz stent implantations for 542 stenoses between November 1995 and July 1998, were analyzed. Sixty-three patients with 78 stenoses received a half stent (group A), 346 patients with 395 stenoses received a single stent (group B), and 68 patients with 69 stenoses received multiple overlapping stents (group C) for a single coronary stenosis. Seventy-eight half stents were implanted in 78 stenoses in group A, 395 stents in 395 stenoses in group B, and 141 stents in 69 stenoses in group C. The baseline characteristics were similar in the 3 groups. There were no deaths, no subacute thrombosis, and no vascular complications. Forty-nine patients with 57 stenoses in group A, 280 patients with 326 stenoses in group B, and 59 patients with 60 stenosis in group C underwent 6-month follow-up coronary angiography; the restenotic rate per patient was 10% in group A, 20% in group B, and 24% in group C (NS); the restenotic rate per stenosis was 9% in group A, 18% in group B, and 23% in group C (NS). Follow-up of 18 +/- 3 months revealed no differences in mortality, reinfarction, recurrent angina, target narrowing angioplasty, and elective coronary artery bypass surgery among the 3 groups. The overall cardiac event-free survival was 90%, 82%, and 83% in groups A, B, and C, respectively (p = 0.275). Thus, the procedural success rate, the in-hospital morbidity, and the long-term outcome are similar with coronary stenting using a half, a single, or multiple overlapping Palmaz-Schatz stents for a single stenosis.

Mechanisms and clinical significance of transient atrioventricular block during dobutamine stress echocardiography

OBJECTIVES

The purpose of this study was to investigate the possible mechanism and the clinical significance of transient atrioventricular block (AVB) during dobutamine stress echocardiography (DSE).

BACKGROUND

Transient AVB occurs rarely during DSE; however, the mechanisms responsible for blocks are unclear.

METHODS

A retrospective analysis of clinical, echocardiographic, catheterization, revascularization and head-up tilting test data was conducted in patients who developed transient AVB during DSE.

RESULTS

A total of 302 patients with known or suspected coronary artery disease (CAD) underwent DSE before coronary angiography between November 1997 and August 1998. Transient AVB developed in 12 patients during the test. Mobitz I block was noted in six patients and Mobitz II block in the other six patients. Nine of these 12 patients were subsequently shown to have CAD and three had no significant coronary artery stenosis. Mobitz II block was observed only in patients with CAD, while Mobitz I block occurred in three patients with and three patients without CAD (p < 0.05). Eight of the nine patients with CAD underwent a successful coronary angioplasty with or without stenting and a repeat DSE revealed no recurrence of heart block except in one patient. Head-up tilting test in the 12 patients revealed a positive response in three of the nine patients with and all three patients without CAD. A negative head-up tilting test was likely to be observed in patients with, as compared with those without, CAD in this study population (p < 0.05).

CONCLUSIONS

Transient AVB is not an infrequent manifestation during DSE. Both myocardial ischemia and neurally mediated vagal reflex may be responsible for this phenomenon. The development of Mobitz II block during DSE is indicative of the presence of CAD. A successful revascularization in patients with CAD who develop transient AVB may abolish this phenomenon.

Loss of heterozygosity in dysplasia and carcinoma of the gallbladder

The loss or inactivation of genes at specific chromosomal loci is one of the important mechanisms during the tumor development in humans. To investigate the role of genetic alterations in the carcinogenesis of gallbladder carcinoma, 32 carcinoma cases and 11 dysplasia cases of gallbladder were analyzed for loss of heterozygosity (LOH) and microsatellite instability (MI) on chromosomal regions 3p, 5q, 8p, 9p, 13q, 17p, and 18q with 17 microsatellite markers. Loss of one allele was identified on chromosomes 5q (55%) and 17p (40%) in dysplasias and on chromosomes 3p (52%), 5q (66%), 9p (52%), and 17p (58%) in carcinomas. LOH on chromosomes 13q and 18q was frequent only in advanced stage (III and IV) carcinomas (40% and 31%, respectively). LOH on chromosome 17p was correlated with intranuclear p53 accumulation. LOH on multiple chromosomes was more frequent in advanced carcinomas with metastasis than in cases without metastasis (P < .05). A widespread MI was observed in only one case of carcinoma. We conclude that LOH on 5q is an early change of carcinogenesis in gallbladder and that LOH on 3p and 9p is related to the progression of gallbladder carcinoma LOH on 13q and 18q is likely to be a late event. LOH on 17p occurs not only in dysplasia but also increases during the subsequent stages. Accumulation of LOH may be associated with carcinogenesis of the gallbladder, but the role of MI may not be significant.

String-plucking as a mechanism of chordal rupture during balloon mitral valvuloplasty using inoue balloon catheter

Percutaneous transvenous mitral commissurotomy using the Inoue technique was performed in a 59-year-old female with mitral stenosis and a severely calcified mitral leaflets. Although not entrapped in the subvalvular apparatus, the balloon catheter was deviated away from the mitral orifice-apex axis of the left ventricle during the inflation of the proximal balloon, which plucked and severed the chordae tendineae of the posterior mitral leaflet and resulted in severe mitral regurgitation.

Gallstone formation and gallbladder mucosal changes in mice fed a lithogenic diet

To investigate the pathologic change of gallbladder mucosa related to gallstone formation, 52 mice were fed a lithogenic diet containing 1% cholesterol and 0.5% cholic acid and we evaluated the sequential morphologic changes in the gallbladder from two days to 40 weeks. Cholesterol gallstones began to appear after two weeks and all the mice had gallstones after eight weeks. At two days, the mitotic index was at its highest. The gallbladder mucosa showed progressive hyperplastic change with earlier papillary projection of the folds and later inward proliferation. At the same time of stone formation, mucous cells forming glands appeared. Their histochemical profile of mucin was different from that of normal epithelium. Numbers of mucous cells increased gradually until 24 weeks but slightly decreased afterward. These results suggest hyperplasia and metaplasia are closely related to the gallstone formation. Hyperplasia is probably reactive to irritating effect of lithogenic bile or stone. Metaplasia and cholesterol gallstone may develop simultaneously, and act synergistically.

A Markov chain model to assess the efficacy of screening for non-insulin dependent diabetes mellitus (NIDDM)

BACKGROUND

The high prevalence and severe consequences of non-insulin dependent diabetes mellitus (NIDDM) in Taiwan calls for urgent measures to detect this disease in the asymptomatic phase. However, the efficacy of early detection of NIDDM is highly dependent on its natural history from the disease-free state, through the asymptomatic to the symptomatic phase and death from NIDDM or other causes.

METHODS

In order to project the above progression, a five-state illness-and-death Markov chain model was proposed to estimate these transition parameters using data from two rounds of a blood sugar screening programme for NIDDM in Puli, in central Taiwan.

RESULTS

Results showed that the annual incidence for asymptomatic NIDDM was 10.67 per 1000 (95% CI: 8.26-13.79) and the average duration between the asymptomatic and symptomatic phases (the sojourn time) was 8 years (95%CI: 5.74-11.29). The 10-year survival rate for asymptomatic NIDDM (79.35%) was better than that for symptomatic NIDDM (69.45%). Prediction of deaths from NIDDM was performed to assess how the efficacy of screening for NIDDM varied by different screening frequencies (annual, biennial, 4-yearly and the control group). Results indicated there is no substantial difference in mortality reduction from NIDDM among the annual, biennial and 4-yearly screening regimens. However, a 4-yearly screening regimen significantly reduced deaths from NIDDM by 40% (95% CI: 26-51%).

CONCLUSIONS

A long sojourn time and the substantial reduction in mortality suggest that a 4-yearly screening regime for NIDDM would be most effective and feasible in Taiwan. The proposed five-state Markov chain model can be applied to other similar NIDDM screening projects.

Solution structure of a sweet protein single-chain monellin determined by nuclear magnetic resonance and dynamical simulated annealing calculations

Single-chain monellin (SCM), which is an engineered 94-residue polypeptide, has proven to be as sweet as native two-chain monellin. SCM is more stable than the native monellin for both heat and acidic environments. Data from gel filtration HPLC and NMR indicate that the SCM exists as a monomer in aqueous solution. The solution structure of SCM has been determined by nuclear magnetic resonance (NMR) spectroscopy and dynamical simulated annealing calculations. A stable alpha-helix spanning residues Phe11-Ile26 and an antiparallel beta-sheet formed by residues 2-5, 36-38, 41-47, 54-64, 69-75, and 83-88 have been identified. The sheet was well defined by backbone-backbone NOEs, and the corresponding beta-strands were further confirmed by hydrogen bond networks based on amide hydrogen exchange data. Strands beta2 and beta3 are connected by a small bulge comprising residues Ile38-Cys41. A total of 993 distance and 56 dihedral angle restraints were used for simulated annealing calculations. The final simulated annealing structures (<SA>k) converged well with a root-mean-square deviation (rmsd) between backbone atoms of 0.49 A for secondary structural regions and 0.70 A for backbone atoms excluding two loop regions. The average restraint energy-minimized (REM) structure exhibited root-mean-square deviations of 1.19 A for backbone atoms and 0.85 A for backbone atoms excluding two loop regions with respect to 20 <SA>k structures. The solution structure of SCM revealed that the long alpha-helix was folded into the concave side of a six-stranded antiparallel beta-sheet. The side chains of Tyr63 and Asp66 which are common to all sweet peptides showed an opposite orientation relative to H1 helix, and they were all solvent-exposed. Residues at the proposed dimeric interface in the X-ray structure were observed to be mostly solvent-exposed and demonstrated high degrees of flexibility.

Antibiotic usage in primary care units in Taiwan

To understand the situation of antibiotic usage in primary care units in Taiwan, we collected all prescriptions over a 1 week period during March 2 to March 7, 1992, December 2 to December 7, 1992, and January 14 to January 19, 1994 from out-patient clinics of public health stations located in various parts of Taiwan. In the first time period 60 health stations were sampled, 18,350 patient-visits made and 23,674 diagnoses recorded. In the second time period 168 health stations were sampled, 84,143 patient-visits made and 96,528 diagnoses recorded. In the third time period 173 health stations were sampled with 85,623 patient-visits and 105,132 diagnoses recorded. The percentages of total patient-visits that resulted in antibiotic treatment were 16.7, 13.5 and 12.4% in the three time periods, respectively. The patient group under the age of 11 received the highest percentage of antibiotic treatment. The percentage of patient-visits that resulted in treatment with two or more types of antibiotics decreased from 25.4% in March, 1992 to 13.2% in January, 1994. Common cold was the most frequent diagnosis in patients receiving antibiotic therapy during the three time periods and accounted for 36.9% of total antibiotic prescriptions. Of the patients with the diagnosis of common cold, 29.7% received antibiotic treatment, of whom the largest group were paediatric patients (< 16 years). Penicillins, macrolides and cephalosporins were the most commonly prescribed antibiotics and accounted for 34.0, 21.8 and 21.3% of all prescribed antibiotics in the three study periods.

Cognition and utilization of Papanicolaou testing after the implementation of National Health Insurance in rural Taiwan

Previous reports have indicated that knowledge and utilization of Papanicolaou (Pap) testing in Taiwan are low, especially among residents of rural areas. However, those studies were conducted before the implementation of National Health Insurance (NHI), which now covers Pap testing. To assess the cognition and utilization of Pap testing after the implementation of NHI in 1995, 708 women aged 40 years or more were interviewed by the Yang-Ming Crusade in July 1997. Of these women, 276 (39%) had heard of the Pap test, 226 (32%) had had the test, and 156 (22%) had had the test in the last 3 years (1995-1997). Of those who had never had the Pap test before 1995, 17% underwent it for the first time after the implementation of NHI. In contrast to an earlier comparable study, the present study shows a significant increase in both the cognition and utilization rates of Pap testing (from 27% to 39%, and 18% to 32%, respectively) among women in rural areas after the test was covered by NHI. However, both knowledge and use of the test among older and lower-educated women are still low.

Papillary endothelial hyperplasia presenting as a chest wall neoplasm

Soft tissue hematomas generally resolve but may persist and develop into slow-growing, organized masses. These chronic expanding hematomas are characterized by a pseudocapsule and a predominantly necrotic central cavity, with foci of newly formed capillaries. These have been called chronic expanding hematomas or Masson's papillary endothelial hyperplasia. These lesions can mimic vascular neoplasms and must be considered in the evaluation of expanding soft tissue vascular malformations.

Expression of foreign antigens on the surface of Escherichia coli by fusion to the outer membrane protein traT

The traT gene is one of the F factor transfer genes and encodes an outer membrane protein which is involved in interactions between an Escherichia coli and its surroundings. This protein was altered so as to permit the expression of foreign proteins on the outer membrane of E. coli in this study. A 729-bp DNA fragment, including the leader and entire structural gene sequence of traT, was amplified and obtained by PCR. This sequence was then subcloned downstream of the tac promoter of pDR540, resulting in a TraT expression vector, pT2. Here, we report that the expression of TraT protein, fused either with a partial pre-S antigen of hepatitis B virus (60 and 98 amino acids, respectively) or with the snake venom rhodostomin (72 amino acids), was successfully achieved on the outer membrane of E. coli, using the pT2 plasmid. This result was demonstrated using dot blot and immunofluorescence analysis. This finding supports the notion that the pT2 plasmid can be used as an E. coli display system. This system can detect a foreign peptide of about 100 amino acid residues in length on the bacterial surface.

Molecular epidemiology and trends of HIV-1 subtypes in Taiwan

To understand the trends of distribution and risk factors associated with different HIV-1 subtypes in different populations in Taiwan, blood samples and questionnaires were collected from 267 male and 21 female HIV-1-infected people in a multicenter survey from 1993 to 1996. This group represented about one quarter of the total registered HIV-1 cases in Taiwan. The HIV-1 subtypes were determined using V3-based peptide-enzyme immunoassays complemented by heteroduplex mobility assay and phylogenetic tree analysis. The results showed that in Taiwan, men were primarily infected with HIV-1B (68.2%) and HIV-1E (27.3%), whereas women were mainly infected with non-B subtypes (4.8% A, 4.8% C, 71.4% E, and 9.5% G). In addition, 71.4% of men with HIV-1B were homosexual or bisexual, whereas 56.2% of men with HIV-1E were heterosexual (p < .001). Although HIV-1E subtype came to Taiwan later than HIV-1B, it has become a major subtype in the heterosexual population.

Late coronary artery stenting in patients with acute myocardial infarction

BACKGROUND

The safety and efficacy of late coronary artery stenting of the infarct-related artery after acute infarction has not been evaluated previously.

METHODS AND RESULTS

Coronary artery stenting was performed in 117 consecutive patients with acute infarction who were receiving ticlopidine/aspirin regimen without coumarin. There were 97 men and 18 women, aged 58+/-11 (mean +/- SD) years. A total of 136 Palmaz-Schatz stents were successfully implanted in 130 lesions 15+/-8 days after acute myocardial infarction (median 9 days) in 115 of 117 (98%) patients. The minimal luminal diameter (MLD) increased from 0.66+/-0.46 to 3.14+/-0.53 mm (P< .001), with an acute gain of 2.49+/-0.61 mm. One patient had acute thrombosis requiring further stenting and another patient received emergency bypass surgery. There was no subacute thrombosis or other complications. During a follow-up duration of 14+/-3 months, 2 patients had angina pectoris develop and 1 died suddenly. Sixty-two patients underwent a follow-up coronary angiography 195+/-36 days after stenting. Restenosis was noted in 8 patients (13%); the MLD was 2.19+/-0.73 mm, the late loss was 0.96+/-0.65 mm (P< .001), the loss index was 0.39+/-0.28, and the net gain was 1.56+/-0.79 mm (P< .001). The angiographic left ventricular ejection fraction increased from 47%+/-12% to 55%+/-12% (P< .001).

CONCLUSIONS

Late coronary stenting of the infarct-related artery in patients with acute myocardial infarction is a safe and effective late reperfusion therapy and may be beneficial to the patients.

Multiplane transesophageal echocardiography in diagnosis of anomalous origin of the left coronary artery from the pulmonary artery: a case report

Anomalous origin of the left coronary artery from the pulmonary artery in adults is difficult to identify reliably by transthoracic echocardiography (TTE). We describe a 32-year-old woman with this coronary anomaly mimicking a coronary artery fistula on conventional TTE study. This anomaly was suggested by multiplane transesophageal echocardiography (TEE) and subsequently confirmed by coronary angiography. Multiplane TEE thus may serve as a first-line diagnostic tool for detecting anomalous origin of coronary arteries.

An epidemic of Malassezia pachydermatis in an intensive care nursery associated with colonization of health care workers' pet dogs

BACKGROUND

Malassezia species are lipophilic yeasts that are emerging as nosocomial pathogens, particularly in low-birth-weight neonates who receive lipid emulsions. When a cluster of patients with Malassezia pachydermatis infection was identified in an intensive care nursery, we initiated an investigation.

METHODS

A case patient was defined as any infant in the intensive care nursery who had a positive culture for M. pachydermatis between October 17, 1993, and January 18, 1995. We conducted a cohort study to identify risk factors for colonization and infection with M. pachydermatis. We collected cultures from the infants and the health care workers and from the health care workers' pets, since this organism has been associated with otitis externa in dogs.

RESULTS

Fifteen infants met the case definition: eight with bloodstream infections, two with urinary tract infections, one with meningitis, and four with asymptomatic colonization. The case patients were significantly more likely than the other infants to weigh 1300 g or less (15 of 65 vs. 0 of 419, P<0.001). In a multivariate analysis of infants weighing 1300 g or less, the independent risk factors for colonization or infection with M. pachydermatis were a greater severity of concomitant illness (odds ratio, 19.7; P=0.001), arterial catheterization for nine or more days (odds ratio, 29.5; P=0.027), and exposure to Nurse A (odds ratio, 74.7; P=0.004). In a point-prevalence survey, 9 additional infants, 1 health care worker, and 12 of the health care workers' pet dogs had positive cultures for M. pachydermatis. The isolates from all 15 case patients, the 9 additional colonized infants, 1 health care worker, and 3 of the 12 dogs had identical patterns of restriction-fragment-length polymorphisms.

CONCLUSIONS

In this outbreak, it is likely that M. pachydermatis was introduced into the intensive care nursery on health care workers' hands after being colonized from pet dogs at home. The organism persisted in the nursery through patient-to-patient transmission.

Phenoloxidase activity of hemocytes derived from Penaeus monodon and Macrobrachium rosenbergii

The phenoloxidase (PO) activity of hemocyte lysate supernatant (HLS) from both tiger shrimp (Penaeus monodon) and giant freshwater prawn (Macro-branchium rosenbergii) was examined by treating HLS with various factors, such as an increase in temperatures from 25 to 70 degrees C, one of four elicitors (beta-1,3-1,6-glucan, zymosan, heat-killed Vibrio cells, and lipopolysaccharide), trypsin, one of three protease inhibitors (soybean trypsin inhibitor, p-nitrophenyl-p'-guanidinobenzoate, and benzamidine), and one of two divalent cations (Mg2+ and Ca2+). The strongest PO activity in both animals was induced at 37 degrees C, while enzyme activity varied according to the concentration of the elicitors or cations added to the HLS samples. The following optimum concentrations were recorded: lipopolysaccharides at 0.5 mg/ml, both beta-glucan and zymosan at 1 mg/ml, and Vibrio cells at 10(6) cells/ml. In addition, for giant freshwater prawn, PO activity increased when HLS was treated with trypsin and decreased when it was separately treated with three protease inhibitors. However, effects of either trypsin or protease inhibitors did not occur in tiger shrimp. Strongest PO activity occurred in HLS treated with 20 mM of either calcium ion or magnesium ion, and the addition of the two cations led to an increase in enzyme activity; a decrease was noted following the treatment with EDTA. Cytochemical analysis revealed that prophenoloxidase system exists in the granulocytes of both tiger shrimp and giant freshwater prawn.

A clinicopathological study of unsuspected carcinoma of the gallbladder

We investigated the incidence of unsuspected gallbladder (GB) carcinomas in a total of 527 consecutive GB specimens resected for benign biliary disease and their clinicopathological features. The GBs were examined microscopically using stepwise tissue sections at 5 mm interval. Clinical and pathological findings were analysed in the cases of unsuspected carcinoma. The 527 patients included 314 women and 213 men (mean age 56.1 years). The incidence of unsuspected GB carcinomas detected during or after cholecystectomy was 1.89%. In ten patients with unsuspected carcinomas, symptoms and signs were nonspecific. Abdominal US showed GB stones (8), thickening of GB wall (1), empyema (2) and a polyp (1). Macroscopically, infiltrative type was the most common. Microscopic examination showed tubular adenocarcinoma. Carcinoma was confined to the mucosa or muscularis (early carcinoma) in 5 cases (50%). The prognosis was good in the patients with early carcinoma, but very bad in advanced cases. In conclusion, unsuspected GB carcinoma was incidentally found in 1.89% of GBs removed for benign biliary disease and a considerable number of these unsuspected cases have an early carcinoma.

A case of intraductal papillary tumor of pancreas associated with mucinous ductal ectasia

Intraductal papillary neoplasm associated with mucinous ductal ectasia is an uncommon cystic disease of the pancreas. This tumor is characterized by the multilocular cyst lined by mucin producing cells with variable degrees of atypia and ductal ectasia. In addition, this tumor has a favorable prognosis in contrast to other mucinous cystic tumor of the pancreas. Reports on intraductal mucin producing tumor are quite limited and most of them are found in Japanese literature. We report a case of intraductal papillary adenocarcinoma with marked dilatation of the pancreatic duct filled with mucin in a 72-year-old female patient.

Ochrobactrum anthropi meningitis in pediatric pericardial allograft transplant recipients

An epidemiologic investigation was done after 3 patients contracted Ochrobactrum anthropi meningitis at one hospital in October 1994. Neurosurgical patients with pericardial tissue implants were at greater risk of infection than other neurosurgical patients (3/14 vs. 0/566; P<.001). Cultures of implants removed from 2 case-patients, an implant at implantation, a nonimplanted pericardial tissue, and an unwrapped but unopened bottle of Hank's balanced salt solution (HBSS) grew O. anthropi. Patient and tissue isolates had identical genotypes; the isolate from the HBSS bottle had a unique genotype. Culture samples from an unopened HBSS bottle and from pericardial tissue grew Pseudomonas stutzeri of the same genotype; however, no P. stutzeri infections were detected. The investigation documented intrinsic P. stutzeri contamination of HBSS. O. anthropi contamination of tissues occurred during processing, possibly due to extrinsic contamination of HBSS. Active surveillance is needed to detect infection in patients receiving transplanted tissues, and rigorous infection control practice are necessary during tissue harvesting and processing to ensure sterility.

Multiplane transesophageal echocardiography in the diagnosis of congenital coronary artery fistula

The purpose of this study was to examine the advantages of multiplane transesophageal echocardiography in the diagnosis of congenital coronary artery fistula, specifically in depicting the origin, the course, and the drainage site. Seven consecutive patients ranging in age from 20 to 72 years with a suspected coronary artery fistula underwent conventional transthoracic and multiplane transesophageal echocardiographic studies between March 1993 and July 1994. When a coronary artery fistula was noted, the origin, the course, and the drainage site were carefully searched for. All patients then underwent a cardiac catheterization with the performance of coronary angiography. A large right coronary artery fistula was detected in three patients; one of them had a drainage to the posterior left ventricle, one to the lateral right ventricle, and the other to the medial aspect of the right ventricle just below the insertion of the septal leaflet of the tricuspid valve. A small coronary artery fistula arising from the left coronary artery was noted in four patients, two from the left anterior descending artery and the other two from the left circumflex artery. Three of these four patients had a drainage to the main pulmonary artery and one to the left ventricle. The drainage site was clearly depicted in all seven patients, whereas the origin and the course were precisely defined in five patients by using multiplane transesophageal echocardiographic examination. The multiplane transesophageal echocardiography provides a panoramic view of the coronary artery and the fistulous vessel with a precise definition of the origin, the course, and the drainage site of the fistula. Therefore it is the noninvasive diagnostic mode of choice.

Canadian physicians considering a move to US can face complicated immigration process

American recruiters are busily trying to coax Canadian physicians to move south of the border to practise, but Canadians must remember that the immigration process can be both lengthy and complicated. In this article, immigration lawyer Henry Chang looks at the requirements that must be met before permanent-resident status is granted by the US.

Diagnosis of coronary artery dissection following blunt chest trauma by transesophageal echocardiography

How to differentiate relevant from trivial cardiac injury in blunt chest trauma has been an ongoing debate. In a 32-year-old victim of a motorcycle crash, the electrocardiographic pattern of an acute anterior wall myocardial infarction was identified as being due to a dissection, after an intimal flap in the proximal left anterior descending artery was noted on transesophageal echocardiography.

HLA and ethnic associations among systemic sclerosis patients with anticentromere antibodies

SSc with ACAs is characterized by limited cutaneous involvement and, in most patients, a mild protracted course. We have studied 104 SSc patients, 47 with ACAs and 57 who were negative for both ACAs and anti-topo I antibodies, for HLA-DR and -DQ associations using DNA typing techniques. Normal controls consisted of 181 healthy individuals. A significant association was observed in the ACA-positive patients with DQB1-0501 (p = 0.001, RR 2.6). There was also a significant decrease in the frequency of DQB1-0201 (p = 0.01, RR 0.33). In addition, the ACA-positive SSc patients were significantly different ethnically from both the other SSc patients and the normal controls (p = 0.004). When patients were stratified according to their ethnic origin and the analysis of HLA associations was repeated, the HLA associations persisted. These results strongly suggest that the development of SSc with ACAs is associated with particular DQB1 alleles, and also that ethnic origin plays a role in disease susceptibility.

Use of transesophageal echocardiography for evaluation of resectability of lung cancer

BACKGROUND

When patients with lung cancer are to undergo surgical resection, chest x-ray and computed tomography (CT) are widely used for evaluation of staging and of the resectability of the lesion. Unfortunately, the above methods cannot always provide sufficient information about resectability and some patients undergo unnecessary operations. Transesophageal echocardiography (TEE) has opened a new window for viewing cardiac structure and function. By TEE, one can also image the surrounding tissues and great vessels under continuous monitoring.

MATERIALS AND METHODS

We pre-operatively applied the awake TEE method in twenty whose chest CT showed suspected invasion of the heart by the tumor.

RESULTS

Our experience showed the following: (1) TEE can clearly identify whether lung cancer has invaded the heart and/or great vessels and therefore avoiding unnecessary operation; (2) Two patients had tumor seen abutting epicardium and/or aorta without invasion (under continuous imaging). Two patients had tumor compressing the right and left atrium with intact but not invading pericardium, and underwent successful surgical resection.

CONCLUSION

We concluded that it is useful to apply TEE preoperatively in evaluating the resectability of the lung cancer especially when a chest CT shows suspicion of local invasion of the heart and great vessels; thus unnecessary thoracotomy can be avoided.

Alteration in multijoint dynamics in patients with bilateral knee osteoarthritis

OBJECTIVE

To document the alterations of joint motion and torque in patients with bilateral knee osteoarthritis (OA), using a well-defined functional maneuver, the sit-to-stand (STS) task.

METHODS

Twelve patients with bilateral knee OA and 12 age-, sex-, and height-matched control subjects performed the STS maneuver from a stool of a standard height at their natural speeds. A motion analysis system and 2 force platforms were employed to determine the dynamic joint motion and the resultant joint torques at the ankle, knee, and hip joints.

RESULTS

The results showed that OA patients exhibited substantially reduced knee extension torques, accompanied by other alterations in initial sitting posture (more extended knee and more plantar-flexed ankle), movement duration (increased), dynamic range of motion at the knee (reduced), and extension torques at the hip (increased).

CONCLUSION

The alterations in joint dynamics among patients with knee OA may have revealed an adaptive motor behavior characterized by redistributing the load from impaired to less-impaired or nonimpaired joints through multijoint dynamics. Two major potential pitfalls of such a movement strategy have subsequently been postulated.

Severe systemic sclerosis with anti-topoisomerase I antibodies is associated with an HLA-DRw11 allele

SSc is an autoimmune connective tissue disease in which strong HLA associations have not been described. Anti-topo I antibodies are recognized, in general, in SSc patients with diffuse cutaneous involvement, whereas anti-ACAs are found in individuals with limited cutaneous involvement. We studied 95 Caucasian SSc patients, 44 with anti-topo I antibodies and 51 with neither anti-topo I nor ACA, for HLA-DR associations by using DNA typing techniques. We analyzed 181 normal Caucasian individuals in the same fashion. A significant association was observed in the anti-topo-I-positive patients with DRw11 (p = 1.7 x 10(-6), RR 4.2). The distribution of DRw11 alleles in these patients was significantly different from that observed in controls and could be accounted for by an increase in the frequency of the DRB1*1104 allele (p = 1.2 x 10(-9), RR 9.5). The DRw11 alleles were also associated with SSc with more tendon friction rubs (p = 0.006), which is a marker of more severe disease. In addition, a strong association was observed with anti-topo I antibodies and a particular sequence (aa 71-77) of the DQB1 chain (p = 0.02, RR 2.2). HLA associations in the case of SSc patients with anti-topo I antibodies are complex and involve at least two genes: HLA-DRw11, which appears to play a major role in determining the severity of the disease, and a DQ sequence, which associates with the development of the anti-topo I antibodies.

Midkine that promotes survival of fetal human neurons is produced by fetal human astrocytes in culture

Midkine (MK), a retinoic acid responsive gene product, is a novel heparin-binding growth factor with an apparent molecular weight of 14-kDa. In fetal human neuron cultures, addition of recombinant human MK (10-100 ng/ml) resulted in a 3-fold increase in the number of surviving neurons under the serum-free culture condition. Production of MK was identified in the conditioned medium of astrocyte-enriched cultures by immunoblotting but not in the medium of neuron-enriched cultures. The level of MK production was not affected by treatment with retinoic acid. These results indicate that in the developing human central nervous system, astrocytes secrete MK that exhibits potent trophic activity to neurons.

Two-dimensional echocardiographic observation of dehiscence of mitral plication annuloplasty suture

Echocardiographic findings of dehiscent suture from mitral plication annuloplasty have not been described. We herein describe transthoracic two-dimensional echocardiographic findings of an abnormal linear echo stretching across the mitral annulus in the left atrium in a 69-year-old male. This abnormal linear echo was confirmed to be a dehiscent plication suture at surgery.

Pattern association and retrieval in a continuous neural system

This paper studies the behavior of a large body of neurons in the continuum limit. A mathematical characterization of such systems is obtained by approximating the inverse input-output nonlinearity of a cell (or an assembly of cells) by three adjustable linearized sections. The associative spatio-temporal patterns for storage in the neural system are obtained by using approaches analogous to solving space-time field equations in physics. A noise-reducing equation is also derived from this neural model. In addition, conditions that make a noisy pattern retrievable are identified. Based on these analyses, a visual cortex model is proposed and an exact characterization of the patterns that are storable in this cortex is obtained. Furthermore, we show that this model achieves pattern association that is invariant to scaling, translation, rotation and mirror-reflection.