Clostridium innocuum, an emerging pathogen that induces lipid raft-mediated cytotoxicity

Clostridium innocuum is an emerging spore-forming anaerobe that is often observed in Clostridioides difficile-associated inflammatory bowel disease (IBD) exacerbations. Unlike C. difficile, C. innocuum neither produces toxins nor possesses toxin-encoding genetic loci, but is commonly found in both intestinal and extra-intestinal infections. Membrane lipid rafts are composed of dynamic assemblies of cholesterol and sphingolipids, allowing bacteria to gain access to cells. However, the direct interaction between C. innocuum and lipid rafts that confers bacteria the ability to disrupt the intestinal barrier and induce pathogenesis remains unclear. In this study, we investigated the associations among nucleotide-binding oligomerization domain containing 2 (NOD2), lipid rafts, and cytotoxicity in C. innocuum-infected gut epithelial cells. Our results revealed that lipid rafts were involved in C. innocuum-induced NOD2 expression and nuclear factor (NF)-κB activation, triggering an inflammatory response. Reducing cholesterol by simvastatin significantly dampened C. innocuum-induced cell death, indicating that the C. innocuum-induced pathogenicity of cells was lipid raft-dependent. These results demonstrate that NOD2 mobilization into membrane rafts in response to C. innocuum-induced cytotoxicity results in aggravated pathogenicity.

Oct4 promotes M2 macrophage polarization through upregulation of macrophage colony-stimulating factor in lung cancer

Background

Expression of Oct4 maintains cancer stem cell (CSC)-like properties in lung cancer cells and is correlated with poor prognosis of lung adenocarcinoma. M2-type tumor-associated macrophages (TAMs) promote cancer cell migration and metastasis. Tumor microenvironments promote monocyte differentiation into M2 TAMs via a complex cytokine-based connection. We explored the role of Oct4 in cytokine secretion in lung cancer and its impact on M2 TAM polarization.

Methods

Monocytes co-cultured with the conditioned medium from Oct4-overexpressing lung cancer cells were used to investigate M2 TAM differentiation. The inflammatory factors in the conditioned medium of Oct4-overexpressing A549 cells were examined using human inflammation antibody arrays. The correlations of Oct4, macrophage colony-stimulating factor (M-CSF), and M2 TAMs were validated in lung cancer cells, syngeneic mouse lung tumor models, and clinical samples of non-small cell lung cancer (NSCLC).

Results

Oct4-overexpressing A549 cells expressed elevated levels of M-CSF, which contributed to increased M2 macrophages and enhanced tumor migration. Overexpression of Oct4 enhanced tumor growth and reduced the survival of lung tumor-bearing mice, which was correlated with increased number of M2 macrophages in lung cancer. Notably, NSCLC patients with high expression levels of Oct4, M-CSF, and M2 TAMs had the poorest recurrence-free survival. A positive correlation between Oct4, M-CSF, and M2 TAMs was observed in the tumor tissue of NSCLC patient. Treatment with all-trans retinoic acid exerted anti-tumor effects and reduced M2 TAMs in tumor-bearing mice.

Conclusions

Our results indicate that Oct4 expressed by lung cancer cells promotes M2 macrophage polarization through upregulation of M-CSF secretion, leading to cancer growth and metastasis. Our findings also implicate that the Oct4/M-CSF axis in M2 macrophage polarization may be potential therapeutic targets for lung cancer.

Exercise-induced myocardial ischaemia complicated by paroxysmal complete atrioventricular block

This study describes a case of exercise-induced myocardial ischaemia accompanied by complete atrioventricular block (CAVB). A 59-year-old man with major depression, treated with regular imipramine and lithium for 20 years, experienced syncope episodes during exercise. Exercise, testing initially, identified ST depression in the inferior leads, and later found CAVB resulting in syncope and seizure. The patient recovered completely after resuscitation. Myocardial ischaemic markers were negative, but 35% stenosis was detected in the distal left main coronary artery by angiography. The combined use of verapamil, nitrate and aspirin was treated as the possible coronary spasm. Repeat treadmill caused negative ischaemic study or exercise-induced arrhythmia, 7 days later. The pathophysiology of the very rare exercise-induced paroxysmal CAVB has been reviewed.

Chemical denaturation and elevated folding temperatures are required for wild-type activity and stability of recombinant Methanococcus jannaschii 20S proteasome

The 20S proteasome from the extreme thermophile Methanococcus jannaschii (Mj) was purified and sequenced to facilitate production of the recombinant proteasome in E. coli. The recombinant proteasome remained in solution at a purity level of 80-85% (according to SDS PAGE) following incubation of cell lysates at 70 degrees C. Temperature-activity profiles indicated that the temperature optima of the wild-type and recombinant enzymes differed substantially, with optimal activities occurring at 119 degrees C and 95 degrees C, respectively. To ameliorate this discrepancy, two recombinant enzyme preparations were produced, each of which included denaturation of the proteasome by 4 M urea followed by high-temperature (85 degrees C) dialysis. The wild-type temperature optimum was restored, but only if proteasome subunits were denatured and refolded prior to assembly (a preparation designated as alpha & beta). In contrast, when proteasome assembly preceded denaturation (designated alpha + beta) the optimum temperature was raised to a lesser degree. Moreover, the alpha & beta and alpha + beta preparations had apparent thermal half-lives at 114 degrees C of 54.2 and 26.2 min, respectively, and the thermostability of the less stable enzyme was more sensitive to a reduction in pH. Attainment of wild-type activity and stability thus required the proper folding of both the alpha- and beta-subunits prior to proteasome assembly. Consistent with this behavior, dual-scanning calorimetry (DSC) measurements revealed differences in the reassembly efficiency of the two proteasome preparations. The ability to produce structural conformers with dramatically different thermal optima and thermostabilities may facilitate the determination of molecular forces and structural motifs responsible for enzyme thermostablity and high-temperature activity.

Importance of hyperhomocysteinemia as a risk factor for venous thromboembolism in a Taiwanese population. A case-control study

OBJECTIVE

To determine the current status of hyperhomocysteinemia, which is a known risk for venous thrombosis (DVT), in Taiwan.

SUBJECTS

101 unselected patients with a minimum of one episode of deep leg DVT, either initial inpatients or current compliant outpatients in a teaching hospital.

METHODS

Various thrombophilic risks, gene polymorphism and clinical predisposition were evaluated.

RESULTS AND CONCLUSIONS

Patients presented higher fast total plasma homocysteine (hcy) levels than age- and sex-matched controls did (14.1 vs. 9.94 microM). Based on the 95th percentile of control values, hyperhomocysteinemia had a four- to nine-fold risk for DVT, irrespective of clinical predisposition, as well as other thrombophilic risks surveyed. Polymorphism of a metabolizing enzyme, methylenetetrahydrofolate reductase (MTHFR), was not associated with DVT, although homozygous thermolabile mutation tended to have higher plasma hcy levels. Factor V Leiden was absent in analysis of 80 patients. In complete evaluation (hcy, antithrombin (AT), protein S (PS), protein C (PC), lupus anticoagulant (LA), anticardiolipin antibody) of a subset of 83 patients hyperhomocysteinemia was the most prevalent risk (33.7%), with PC or PS deficiencies following (22.9%). Thus, hyperhomocysteinemia is a prominent risk for DVT in Taiwan.

Beard dermatitis due to para-phenylenediamine use in Arabic men

The most common active ingredient in hair coloring is para-phenylenediamine (PPDA), which can produce contact dermatitis, particularly in persons who dye their scalp hair and in hairdressers. We have identified another group of patients also at risk, namely men from Arab countries, who commonly grow beards and dye them. We searched the computerized patient database at the Mayo Clinic for patients with beard dermatitis associated with dye use. Eight Arabic men presented to the Mayo Clinic between 1994 and 1999 with beard dermatitis and a positive patch test to PPDA. The lesions were described as pruritic, erythematous, papular eruptions that developed in the jaw area after each application of beard dye. The symptoms subsided after the patients discontinued use of the PPDA-containing dye and received treatment with topical corticosteroids. Allergic contact dermatitis in the beard area due to PPDA occurs in Arabic men as a result of their propensity to dye their beards.

The C677T mutation of the methylenetetrahydrofolate reductase gene is not associated with the risk of coronary artery disease or venous thrombosis among Chinese in Taiwan

OBJECTIVES

We sought to investigate the association between the methylenetetrahydrofolate reductase (MTHFR) gene C677T mutation and the risk of coronary artery disease (CAD), myocardial infarction (MI) and venous thrombosis (VT) in a Chinese population in Taiwan.

METHODS

The subjects included 218 CAD patients, 107 VT patients, and their age- and sex-matched controls. DNA was extracted from the blood and genotypes were determined by polymerase chain reaction, restriction mapping with HinfI and gel electrophoresis.

RESULTS

The distribution of MTHFR genotypes was similar in the CAD cases and controls; the genotype TT was present in 6.0% of CAD patients, as compared to 6.9% of CAD control subjects (p = 0.165; odds ratio = 0. 86; 95% confidence interval = 0.40-1.85). The frequency of the T allele was also similar in CAD cases and controls (25.5% vs. 24.8%; p = 0.788). There was no significant association between TT homozygosity and the risk of MI. The genotype distributions and the frequency of the T allele were also similar in VT cases and controls.

CONCLUSIONS

Our data suggest that there is no association between the C677T mutation of the human MTHFR gene and the risk of CAD or VT among Chinese in Taiwan.

Superior vena cava syndrome as a complication of transvenous permanent pacemaker implantation

Venous thrombosis induced by a transvenous permanent pacemaker is a common complication. However, superior vena cava (SVC) syndrome caused by pacemaker leads is only occasionally seen and its prevalence has been estimated to be less than 1 in 1000 pacemaker patients. Herein, we report a Taiwanese patient of high grade AV block, who presented with SVC syndrome 2 years after transvenous permanent pacemaker implantation. This case features fibrotic stenosis of the junction of right brachiocephalic trunk and SVC, and an extensive thrombus formation resulting in complete obliteration of the left brachiocephalic vein. The collateral circulation was so delicate that he still could lead a rather normal life, even if anticoagulant therapy proved to be ineffective from an angiographic point of view.

Critical appraisal of exercise variables: a treadmill study

BACKGROUND

New criteria for diagnosing ischemic response to treadmill exercise testing (TET) have continuously been proposed. Simultaneous comparison of test performances according to these criteria is likely contributory to interpreting TET and needs to be updated time after time. This study was conducted to accomplish this end.

METHODS

A comparison of test performances of various TET variables for a cohort of 107 clinical normals and 139 angiographic patients with normal resting electrocardiograms was performed. Angiographic references included enumeration of diseased coronary vessels, Gensini's and Duke's coronary scores, left ventricular wall motion score and ejection fraction at rest.

RESULTS

The ST-segment-related variables (depression, integral, and heart-rate-adjusted slope or index) outdid non-ST-segment variables (changes in R amplitude, the Athens QRS score, peak exercise blood pressure increment and recovery pressure ratios; most P < 0.05) in diagnosing coronary artery disease. Among them the heart-rate-adjusted ST-segment depression performed still better. This trend was not evident in identifying left main and three-vessel disease. However, correlation to the coronary scores favored the ST-segment-related criteria (r = 0.18-0.39, P < 0.05 to P < 0.001 versus r = 0.05-0.23, NS to P < 0.01) for evaluating severity of coronary artery disease.

CONCLUSIONS

For patients with normal resting electrocardiograms, the adjustment of ST-segment depression for heart rate is valuable for evaluating coronary artery disease.

Characterization of atrioventricular nodal reentry with continuous atrioventricular node conduction curve by double atrial extrastimulation

BACKGROUND

Characterization of typical atrioventricular nodal reentrant tachycardia (AVNRT) with continuous AVN conduction (A1A2/A2H2) curves by double atrial extrastimulation (A1A2A3) has never been systematically studied.

METHODS AND RESULTS

This study was composed of 33 patients with typical AVNRT and continuous AVN conduction curves (group 1) and 103 patients with AVNRT and discontinuous AVN conduction curves (group 2). Using A1A2A3 with predefined fast pathway-conducted A2, we examined the effects of slow pathway ablation on the A2A3/A3H3 curves in both groups. In group 1, anterograde AVN effective refractory period (272+/-33 versus 277+/-47 ms, P>0.05) and AVN Wenckebach block cycle length (320+/-45 versus 343+/-59 ms, P>0.05) remained unchanged after ablation. A2H2max was shorter in group 1 than group 2 (237+/-89 versus 395+/-72 ms, P<0.05) at baseline. It shortened in group 2 (395+/-72 versus 221+/-78 ms, P<0.001) but remained unchanged in group 1 (237+/-89 versus 214+/-59 ms, P>0.05) after ablation. A1A2A3 could further disclose discontinuous A2A3/A3H3 curves in 29 patients of group 1. A3H3max shortened in both groups (375+/-81 versus 238+/-82 ms, P<0.001, and 419+/-104 versus 220+/-78 ms, P<0.001, respectively) in a similar fashion. Successful ablation resulted in loss of the left portion of the A2A3/A3H3 curves in the 4 patients of group 1 with continuous A2A3/A3H3 curves.

CONCLUSIONS

Use of A1A2A3 could expose discontinuous A2A3/A3H3 curves in most patients with continuous A1A2/A2H2 curves. Significant shortening of A3H3max after ablation may be indicative of successful elimination of AVNRT.

Gender differences in baseline variables, therapies and outcomes in Chinese patients with acute myocardial infarction

We prospectively studied the gender differences of baseline variables, therapies, and outcomes among a cohort of 369 Chinese patients with acute myocardial infarction from 1990 to 1995. There were 277 male and 92 female patients. The male gender had a younger mean (+/-SD) age (61.5+/-10.7 vs. 67.1+/-11.7 years, P<0.0001). Hypercholesterolemia (201.2+/-44.2 vs. 187.5+/-43.7 mg/dl, P=0.0111) and obesity (25.0 vs. 15.9%, P=0.0494) were more prominent in the female. Smoking was more prevalent in the male (78.3 vs. 18.5%, P<0.0001). The male group also had more frequent use of thrombolytic agents (19.1 vs. 9.8%, P=0.0377), beta-blockers (61.7 vs. 47.8%, P=0.0191) and heparin (25.3 vs. 12.0%, P=0.0075); but less use of angiotensin-converting enzyme inhibitors (6.9 vs. 15.2%, P=0.0149). The condition on admission was worse in the female group (Killip classification (1.5+/-0.9 vs. 1.9+/-1.0, P=0.0022), myocardial failure (8.7 vs. 2.9%, P=0.0178) and cardiomegaly (65.2 vs. 53.1%, P=0.0419). During a follow-up duration of 26.4+/-24.1 and 22.9+/-23.9 months respectively, the mortality rate was lower in the male (19.5 vs. 30.4%, P=0.0288). However after adjustment for the effect of age, the differences in Killip classification, myocardial failure, cardiomegaly and mortality became insignificant.

Unusual coronary artery ectasia and stenosis in a patient with systemic lupus erythematosus and acute myocardial infarction

Acute myocardial infarction is an important and sometimes fatal complication of systemic lupus erythematosus (SLE). We describe a case of acute myocardial infarction in a 23-year-old woman with SLE. Angiography revealed coronary ectasia in the left main and proximal circumflex coronary arteries, as well as a stenotic lesion in the left anterior descending artery. The possible pathophysiology is discussed.

Interaction between obesity and genetic polymorphisms in the apolipoprotein CIII gene and lipoprotein lipase gene on the risk of hypertriglyceridemia in Chinese

To understand the effects of the interaction between genetic polymorphisms and obesity on the risk of hypertriglyceridemia (HTG), two polymorphisms, an SstI polymorphism on the apolipoprotein CIII gene and a HindIII polymorphism on the lipoprotein lipase gene, were analyzed in 339 Chinese subjects with (82 cases in the HTG group) or without HTG (257 cases in the control group). Our data revealed that the frequencies of obesity, the SstI minor allele (S2), and the HindIII major allele (H+) in the HTG group were significantly higher than in the control group. Subgroup analysis revealed that the association between these two polymorphisms and HTG occurred predominantly in nonobese subjects and in subjects with the less hypertriglyceridemic genotype of another polymorphism. Multivariate logistic regression analysis showed that all three risk factors (obesity, S2-containing chromosome, and H+ homozygosity) were associated with HTG, and an interaction was found between obesity and H+ homozygosity for the occurrence of HTG. The risk of HTG increased significantly with combinations of risk factors. Subjects can be divided into low or high risk groups for HTG using such combinations. These results provide evidence of interaction between obesity and the HindIII polymorphism of the lipoprotein lipase gene on the risk of HTG.

Angiotensinogen and angiotensin-I converting enzyme gene polymorphisms and the risk of coronary artery disease in Chinese

The homozygous deletion allele (DD) of the angiotensin-I converting enzyme (ACE) gene and the T235 homozygote of the angiotensinogen (AGT) gene have been reported to be correlated with an increased prevalence of coronary artery disease (CAD) and myocardial infarction (MI). The importance of the DD genotype and T235 homozygote as genetic risk factors for CAD in Chinese remains uncertain. This study included 426 patients who underwent coronary angiography and 180 healthy subjects without clinical evidence of CAD. Coronary angiography identified 268 patients with CAD (CAD group) and 158 patients without CAD. The healthy subjects and patients without angiographic evidence of CAD constituted the control group. Three polymorphisms were studied: an insertion/deletion (I/D) polymorphism of the ACE gene and the T174 M and M235T polymorphisms of the AGT gene. No association was found between any of the three studied polymorphisms and the risk of CAD or MI in Chinese using univariate or multivariate analysis. In multivariate analysis, the relative risks were 1.20 (95% confidence interval = 0.91-1.61, P = 0.20) for the DD genotype, 1.05 (95% CI = 0.82-1.35, P = 0.69) for the T174 homozygote, and 1.19 (95% CI = 0.91-1.55, P = 0.20) for the T235 homozygote. Similarly, no significant difference was found in the frequencies of the DD genotype and the T174 and T235 homozygotes between the control group, the CAD group, the non-MI group, and the MI group when analyzed according to sex, age, or degree of risk. Our data suggest that neither the DD genotype of the ACE I/D polymorphism nor the T174 and T235 homozygotes of the AGT gene confer significant risk for CAD or MI in Chinese.

Deep venous thrombosis in Taiwan

We retrospectively reviewed all patients with a final diagnosis of deep venous thrombosis (DVT) treated at Linkou Chang Gung Memorial Hospital between 1989 and 1995. There were a total of 245 patients with a mean age of 58 years (males 56 and females 59), ranging from 11 to 89 years. The ratio of left to right leg involvement was 2.4 to 1 (166 to 71), however, the right leg was more likely to lead to an acute pulmonary embolism, with a ratio of 3.0 to 1 (9/ 71 to 7/166 patients). Among these patients, 16.3% (40) had cancer. The most frequently involved system was the GI system (16). Adenocarcinoma proved the most common type of malignancy 62.5% (25/40). From this analysis, we found the left leg had a higher likelihood of thrombosis but a DVT of the right leg was more frequently associated with an acute pulmonary embolism. As with previous reports there was a strong relationship between cancer and DVT and the development of a deep venous thrombosis requiring a search for an underlying malignancy in those patients with an unexplained DVT.

The G1691A mutation of the coagulation factor V gene (factor V Leiden) is rare in Chinese: an analysis of 618 individuals

To understand the allele frequency of the G1691A mutation of the coagulation factor V gene (factor V Leiden) in Chinese, 618 Chinese individuals, including 54 cases with venous thrombosis, were analyzed. Only one case in the control group was heterozygous for the 1691G allele and the 1691A allele. Our data suggest that the factor V Leiden is rare in Chinese.

Extensive bullae formation in acute iliofemoral venous thrombosis

A 58-year-old man presented with an acutely painful swollen left leg which was cyanotic and crowded with cutaneous bullae. After confirmation with color duplex ultrasound, intravenous streptokinase therapy was commenced with a bolus of 250,000 i.u. followed by maintenance infusion of 100,000 i.u. hourly for 72 hours. Treatment was changed to heparin for 14 days and then oral warfarin for another 6 months. Effacement of bullae accompanied subsidence of swelling of the leg. This case highlights the potential contribution of fluid retention in acute deep venous thrombosis to extensive bullae formation. This has not been previously reported in the literature.

Defecation induced deep venous thrombosis. A case report

While the risk of deep venous thrombosis (DVT) during prolonged fights is well recognized, we present the case of a 54-year-old male who suffered a deep venous thrombosis following defecation. Defecation, through a combination of the Valsalva maneuver and squatting, led to a DVT due to venous stasis, most marked in the left leg. Color-duplex scanning not only proved a convenient diagnostic tool but also allowed for monitoring and documentation of popliteal and saphenous vein recanalization. Being non-invasive and complication-free, color-duplex scanning should be considered for any patient in whom DVT is a possibility.

Comparisons between female and male patients with mitral stenosis

OBJECTIVE

To compare Doppler, echocardiographic, and clinical variables in female and male patients with mitral stenosis.

DESIGN

Observational study in consecutive patients with mitral stenosis of cross sectional and Doppler echocardiographic and clinical variables and a retrospective search for a history of systemic embolism.

SETTING

A medical centre with 3000 beds, serving both urban and rural populations.

PATIENTS

500 consecutive patients with an echocardiographic mitral valve area of 2 cm2 or less. 331 (66.2%) were female and 169 (33.8%) male (mean (SD) ages of 49 (13) and 48 (14) respectively).

MAIN OUTCOME MEASURES

Mitral valve areas by echocardiographic planimetry and Doppler pressure half-time method, peak early diastolic mitral velocity and pressure gradient, echocardiographic score of mitral valve, left atrial end systolic diameter, frequency of left atrial thrombus and smoky echoes as well as various valve lesions detected with Doppler and echocardiography, cardiac rhythm, symptomatic functional class of heart failure, and history of systemic embolism.

RESULTS

The prevalence of significant tricuspid (22% v 9%, P < 0.001) and pulmonary regurgitation (5% v 1%, P = 0.018) was higher in the female patients than in the male patients. Female patients also had a higher peak regurgitant velocity (3.2 (0.7) v 2.9 (0.7) m/s, P = 0.007) and pressure gradient (41 (21) v 36 (19) mm Hg, P = 0.010) across the tricuspid valve. However, the male patients had a higher echocardiographic score (9.7 (2.4) v 7.0 (2.3), P < 0.001) and a smaller Doppler-derived mitral valve area (0.9 (0.4) v 1.0 (0.4) cm2, P = 0.027). There were no differences between the female and the male patients in mitral valve area measured by planimetry, peak early diastolic mitral velocity and pressure gradient, and left atrial end systolic diameter or in the prevalence of atrial fibrillation, left atrial thrombus, left atrial smoky echoes, significant aortic stenosis, aortic regurgitation, or heart failure of New York Heart Association class III or IV.

CONCLUSIONS

Female patients not only had a higher prevalence of mitral stenosis but also had a higher prevalence of associated tricuspid and pulmonary regurgitation along with a higher velocity and gradient of tricuspid regurgitation. The echocardiographic score was higher in male patients, however. These findings suggest that the pathophysiology of mitral stenosis is different in the two sexes and that gender should be taken into account when therapeutic strategies are formulated.

Noninvasive predictors of systemic embolism in mitral stenosis. An echocardiographic and clinical study of 500 patients

Few predictors of systemic embolism in patients with mitral stenosis have been identified by noninvasive methods. This study used the most powerful noninvasive diagnostic tool, transthoracic echocardiography, as well as other noninvasive clinical information to look for predictors. Five hundred consecutive patients with a mitral valve area of 2 cm2 or less were studied. They were divided into two groups: group 1 consisted of 143 patients with a history of systemic embolism and group 2 consisted of 357 patients with no history of systemic embolism. Using a stepwise logistic regression on a random subsample of 400 patients, 4 independent predictors were found: the presence of atrial fibrillation (p = 0.003, relative risk [RR] = 2.3, 95% CI = 1.3, 4.2), the absence of significant tricuspid regurgitation (p = 0.008, RR = 2.5, 95% CI = 1.3, 4.9), the absence of aortic regurgitation (p = 0.022, RR = 2.2, 95% CI = 1.1, 4.2), and the presence of left atrial smoky echoes (p = 0.039, RR = 1.7, 95% CI = 1.1, 3.0). When the above model, together with significant interaction terms, was applied to the remaining 100 patients, both the Hosmer-Lemeshow and Brown goodness-of-fit statistics were not significant (p = 0.888 and p = 0.248, respectively), indicating that the fit was adequate and the model was validated. Thus, important noninvasive predictors of systemic embolism in patients with mitral stenosis can easily be obtained. Subgroups of patients with high risk of systemic embolism can be identified. This may refine our therapeutic strategies to prevent the catastrophe of systemic embolism.

Effect of mitral regurgitation and aortic regurgitation on Doppler-derived mitral orifice area in patients with mitral stenosis

Traditional Doppler pressure half-time (T1/2) method (mitral valve area = 220/T1/2) is widely used for evaluating the mitral orifice area in patients with mitral stenosis (MS). However, the effect of mitral regurgitation (MR) and aortic regurgitation (AR) on the calculation of the mitral valve area by this method is still controversial. Therefore, we examined 493 consecutive patients with MS to evaluate the effect of MR and AR on Doppler-derived mitral orifice area. The mitral orifice area planimetered from two-dimensional echocardiogram was used as the standard reference. Excluding 16 patients with either unsatisfactory Doppler or echocardiographic tracings, 477 patients were enrolled in the study. There were 162 males and 315 females with a mean age of 49 years. They were divided into 4 groups: group A, 327 patients with MS but no MR and AR; group B, 68 patients with MS + MR but no AR; group C, 64 patients with MS + AR but no MR; group D, 18 patients with MS + MR + AR. The differences between echo and Doppler area were 0.02 +/- 0.02 cm2 (mean +/- SE), p = 0.220, in group A; 0.13 +/- 0.04 cm2, p = 0.004, in group B; 0.11 +/- 0.05 cm2, p = 0.026 in group C; and 0.31 +/- 0.08 cm2, p = 0.001, in group D. Thus, in patients with MS, the associated MR or AR may invalidate the pressure half-time method for the derivation of mitral valve area.

Diagnostic use of metoclopramide in hypertension caused by pheochromocytoma

We studied 5-mg metoclopramide provocation in six pheochromocytomatous patients with different tumor locations, varying secretory patterns and large tumor sizes (> 12 g or equivalently) and in 14 patients with essential hypertension as part of diagnostic work-up, usually after screening with vanillylmandelic acid assay by the colorimetric method. Antihypertensive medication continued in three and five patients, respectively. Despite similar basal blood pressures patients with pheochromocytomas developed more prominent pressor responses in five of six patients than the nonpheochromocytomatous patients (P < 0.01), most (10) of the latter with negligible pressor responses. Basal plasma catecholamines were higher in each of the pheochromocytomatous patients of different secretory patterns. Further rises after provocation were seen in all pheochromocytomatous patients except one with early pressor response, and also in one nonpheochromocytomatous patient. All tests were well tolerated. Thus, we concluded that the metoclopramide test based upon joint pressor response and plasma catecholamine response can be safely used in the diagnosis of pheochromocytoma. A less stringent protocol including a short drug-off preparatory period may be a warranted compromise between feasibility and diagnostic accuracy.

In-utero sound levels when vibroacoustic stimulation is applied to the maternal abdomen: an assessment of the possibility of cochlea damage in the fetus

OBJECTIVE

To measure sound pressure level in utero while a vibro acoustic stimulator is applied to maternal abdomen and to calculate whether the estimated effect on fetal cochlea cilia vibration would be hazardous.

DESIGN

Prospective descriptive study.

SETTING

Labour ward, National University Hospital, Singapore.

SUBJECTS

Eight women undergoing induction of labour.

INTERVENTION

A hydrophone was introduced via the cervix into the uterus and placed under ultrasound guidance near the fetal ear. Sound pressure was recorded when a vibroacoustic stimulator was applied directly to the maternal abdomen and also when separated by 2 cm of air.

MAIN OUTCOME MEASURES

Sound pressure levels in utero.

RESULTS

The sound level recorded from the vibrator diaphragm in air was 107 dB at 2 cm and 74 dB at 1 m. The mean sound pressure level in utero was 90.7 dB (range 75-96 dB) when the vibrator was in contact with the abdominal wall and 80.1 dB (range 70-88 dB) when separated by 2 cm of air.

CONCLUSIONS

Analysis of factors affecting displacement of cochlear sensing cilia in utero show that, for equal sound pressures, sound intensity and sound vibration are about 4000 times less in amniotic fluid, compared to that produced in air. Further protection is provided by viscous and hydrodynamic features of the ear. The estimated effect on cilia vibration by the mean sound pressure registered in utero, about 90 dB, corresponds to that produced postnatally by an airborne sound registering about 40 dB, which would not be hazardous.

Vibroacoustic stimulation and intrauterine sound pressure levels

The sound pressure level in amniotic fluid generated by vibroacoustic stimulation, assessed with a hydrophone placed close to the fetal head, was studied in 16 subjects. The mean recorded sound pressure level was 115 dB and the highest level was 129 dB. The range of the background noise was 63.5-80.5 dB. There was no obvious relationship between the distance from the stimulator to the hydrophone and the intrauterine sound pressure level. Although sound pressure levels are high, they are probably reduced before reaching the cochlea of the fetus because of the surrounding amniotic fluid and the fluid in the middle ear.

Endpoints of treadmill exercise testing for functional evaluation of patients with mitral stenosis

The study was performed on 122 patients proved by catheterization to have dominant mitral stenosis so as to define proper endpoints of exercise testing for functional evaluation. This represents the 14-year experience with mitral stenosis in our exercise laboratory. Of them, we investigated 126 who completed clinically event-free Naughton treadmill exercise tests. Excess peak exercise heart rates (over 150 beats per minute, 63%) and exertional hypotensive responses (59%, probably including factitious responses due to unreliable indirect pressure readings) did not correlate with the severity of mitral stenosis. Without limiting symptoms and major ventricular arrhythmias, either of the above as endpoints may cause the test to be halted prematurely in half the cases. Ventricular arrhythmias (60%; in complex forms, 20%; possibly contaminated by aberrancy in atrial fibrillation and aggravated by digitalis/diuretics) did not correlate with severity of stenosis either, but the only one major complication we met was secondary to ventricular tachyarrhythmia. Limiting symptoms (83%; of them 94% being dyspnea/fatigue correlating with severity at P less than 0.01) and complex ventricular arrhythmias as endpoints terminated 85% of the tests safely in this series. Atrial thrombuses (34%, all non-floating) did not cause any related complications. Thus, we concluded that limiting symptoms and complex ventricular arrhythmias are the proper endpoints in evaluating the exercise capacity of patients with mitral stenosis after prior echocardiographic exclusion of those with potentially risky floating thrombus.

Postoperative echocardiographic study of patients with symptomatic chronic aortic regurgitation

Aortic valve replacement was performed in 31 patients with symptomatic chronic aortic regurgitation. The patients ranged in age from 13 to 66 (mean = 39) years and included 29 men and 2 women. They were followed up for a mean of 47 months. Perioperatively, 2 patients (6.5%) died, and 2 (6.5%) received a permanent pacemaker for complete heart block. Thirty patients received an M-mode echocardiographic examination both before, and 6 to 11 days after, the operation. In this early postoperative period, the end-diastolic dimension (EDD) and left ventricular end-diastolic radius/posterior wall thickness ratio (R/Th) decreased in all patients. This decrease in EDD could be predicted by preoperative ejection fraction (EF), but not by end-systolic dimension (ESD) or R/Th ratio. The ESD regressed only in patients with preoperative EF greater than 50%, or ESD less than 55mm, or R/Th less than 3.8. During the long-term follow-up, one each had mild tissue valve degeneration, stroke, infective endocarditis, and severe myocardial failure, but none died. Eighteen patients had repeated M-mode echocardiographic studies. There was no further regression of EDD and R/Th, while ESD showed significant decrease. The EF and fractional shortening (FS) did not change. Clinically, the patients who survived the operation improved or remained unchanged postoperatively in a functional status. However, those who had preoperative EF greater than 50% or ESD less than 55mm had a better postoperative functional class (1.2 +/- 0.4 vs 1.9 +/- 1.0, p less than 0.05, 1.2 +/- 0.4 vs 2.0 +/- 1.1, p less than 0.05, respectively). Thus, patients with symptomatic chronic aortic regurgitation can often benefit from valve replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Immediate prognostic significance of complete atrioventricular block in acute myocardial infarction

To discern the relative prognostic role of complete atrioventricular block (CAVB) in patients with acute myocardial infarction (AMI), 908 consecutive patients with AMI were studied over a 7-year period. Of the 559 patients with anterior wall AMI, 13 (2.3%) demonstrated CAVB, of whom 10 (76.9%) died in the hospital (vs 10.4% in those without CAVB) (p less than 0.001). In 349 patients with inferior wall AMI, 30 (8.6%) developed CAVB, of whom 6 (20%) died (vs 6.3% in those without CAVB) (p less than 0.01). In anterior wall AMI, all 5 patients with narrow QRS complexes (vs 8/11 with wide QRS complexes) (p = NS) died; in inferior wall AMI, 4/25 with narrow QRS complexes (vs 2/5 with wide QRS complexes) (p = NS) died. The mortality rate of patients with an escape frequency of less than or equal to 50/min did not differ significantly from that of patients with greater than 50/min regardless of the site of infarction or whether a pacemaker was used. In anterior wall AMI, the mortality rate of paced patients was 70% (7/10) compared to 100% (3/3) of non-paced patients (p = NS). In inferior wall AMI, the mortality rate of paced (5/25) and non-paced (1/5) patients was both 20%. Thus, none of the clinical parameters such as escape rhythm, the width of escape QRS complexes and pacemaker therapy discriminated the survivors from the deaths. In anterior wall AMI, episodes of cardiac standstill or bradycardia were of short duration, and pacemaker therapy was only one of the therapies applied.(ABSTRACT TRUNCATED AT 250 WORDS)

Early diagnosis of acute myocardial infarction by myoglobin latex agglutination test

Early elevation of the serum myoglobin level in acute myocardial infarction (AMI) has been noted for years. In this study, 39 patients admitted to the Coronary Care Unit with acute chest pain within 72 hours (mean 12 +/- 15 hours) or electrocardiographic changes suspected of acute myocardial infarction had a serum myoglobin latex agglutination test to evaluate its diagnostic accuracy in acute myocardial infarction. Of these 39 patients, 24 had documented acute myocardial infarction as their final diagnosis. By the time of admission, 18 of the 24 cases with infarction had positive myoglobin tests (sensitivity 75%). Of those 15 cases without myocardial infarction, 13 had negative myoglobin tests (specificity 87%). If only those 17 cases admitted within 5 hours of the onset of chest pain were analyzed, the serum myoglobin test became positive in 8 of 10 cases with documented AMI but the 2 cases with negative results turned positive 2 hours later (sensitivity 80% to 100%). Due to the fact that myoglobin tests were negative in all other 7 cases without infarction, the specificity was 7/7 (100%). In contrast, the creatine phosphokinase isoenzyme study was positive only in 3 of these 10 patients with documented AMI in the first blood sample taken during admission. In conclusion, the serum myoglobin latex agglutination test is a quick and reliable method that helps in the early diagnosis of acute myocardial infarction.

[Evaluation of the apical seal produced by a hybrid root canal filling method, combining lateral condensation and thermomechanical compaction]

The present study measured apical leakage to a dye in roots filled by a hybrid root canal filling method, combining lateral condensation and thermomechanical compaction. The canals of 52 extracted human maxillary anterior teeth were endodontically prepared and divided into 3 groups. Lateral condensation was used in one group. The roots of the second one were filled using thermomechanical compaction. The roots of the third group were filled using hybrid method. After immersion in Procion Brilliant Green, the roots were cleared for measuring the depth of penetration of the dye under stereomicroscope. The roots filled with the hybrid method leaked less than the lateral condensation group, yet the difference was not significant (P greater than 0.05). The roots filled with both hybrid method and lateral condensation leaked significantly less (p less than 0.05) than the thermomechanical compaction group.

Relationship between reestablishment of sarcolemma-glycocalyx ultrastructures and restoration of transmembrane potentials in cultured rat heart cells

Simultaneous studies on sarcolemma-glycocalyx ultrastructures and electrophysiological properties of the trypsin-released rat heart cells were carried out in order to define the relationship between sarcolemmal membrane repair and transmembrane potential recovery in the long-term cultured heart cells. Based on electron microscopic observations of the trypsinized heart cells maintained in the long-term culture, serial alterations of sarcolemma-glycocalyx complex could be divided into three successive stages. A defective stage of the sarcolemma-glycocalyx complex was present in the cultured cells between day 3 and day 6 of incubation. A repaired stage of the sarcolemma-glycocalyx complex was observed in the cells from day 7 to day 9 of incubation. A well-organized stage of the sarcolemma-glycocalyx complex was seen in the cells after ten days of incubation. Sequential measurements of electrophysiological parameters of the cultured heart cells showed a diphasic evolution of maximum diastolic potential and action potential amplitude, with an initial decrease from day 3 to day 9 of incubation and a later return to normal range after ten days of incubation. There seemed a good correlation between electrophysiological properties and sarcolemma-glycocalyx ultrastructures. Thus, we conclude that restoration of the electrophysiological properties of the cultured cells is closely related to the reorganization of the defective sarcolemmal membrane.

Importance of adequate gas-mixing in contrast echocardiography

Microbubble formation has been accepted as the mechanism producing contrast echoes. Comparisons of the contrast effects of various agents have been studied extensively, but the importance of gas-mixing has been less appreciated. To test the hypothesis that good gas-mixing, by facilitating microbubble formation, would enhance contrast effect, this study compared the contrast echocardiograms of ten adult patients before and after mixing carbon dioxide with various contrast agents. Contrast agents tested included a 5 percent glucose in water, vitamin B complex, vitamin C, and Cardiogreen solutions. First, we recorded echocardiograms by injecting each diluted contrast solution alone, then repeated the examinations using 10 ml of each diluted solution with 1 ml of carbon dioxide (CO2), mixed by means of a four-way stopcock. Satisfactory or excellent results were obtained in seven of ten, ten of ten, ten of ten, and ten of ten tests, respectively, after thorough gas-mixing, vs one of ten, seven of ten, eight of ten, and six of ten, respectively, before gas-mixing. We conclude that the addition of sufficient amounts of gas, followed by thorough mixing, is of great importance in contrast echocardiography. Consistently good results can be achieved with vitamin C, vitamin B or Cardiogreen solutions by this simple and safe method.

Early postoperative echocardiographic studies of atrial septal defects

Fifteen consecutive adult patients with uncomplicated atrial septal defects (ASD) underwent echocardiographic examinations both before and 3-8 days (mean 7 days) after surgery to study the early postoperative changes in cardiac dimensions and interventricular septal motion. Echocardiographic analyses included patterns of interventricular septal motion, right and left ventricular dimensions at end-diastole (RVDd & LVDd), aortic root dimension at end-diastole (ARDd) and left atrial dimension at end-systole (LADs). The results showed that the septal motion was abnormal in 87% (13/15) before and 40% (6/15) after operation. RVDd decreased from 36 +/- 7 mm to 27 +/- 7 mm (p less than 0.01) while LVDd increased from 33 +/- 6 mm to 39 +/- 4 mm (p less than 0.01). There were no significant changes in LADs and ARDd after surgery. These observations suggest that in patients with ASD the ventricular dimensions and patterns of interventricular septal motion are changed significantly shortly after surgical repair.

Cardiac dimensions and motion shortly after mitral valve surgery

We studied 71 adult patients echocardiographically both before and 2-16 days (mean 8 days) after mitral valve surgery to systematically evaluate the early postoperative changes in cardiac dimensions and motion. The patients were divided into 4 groups: group I with predominant mitral stenosis (MS) (26 patients), group II with predominant mitral insufficiency (MI) (12 patients), group III with MS + MI (16 patients) and group IV with combined mitral and aortic valvular disease (17 patients). After operation the left atrial dimension at endsystole decreased (mean +/- standard deviation, 56 +/- 12 mm vs 46 +/- 11 mm, p less than 0.001), but did not completely normalize in the majority of patients. The left ventricular dimension at enddiastole decreased in group II from 67 +/- 12 mm to 54 +/- 5 mm (p less than 0.01) and in group IV from 59 +/- 13 mm to 54 +/- 13 mm (p less than 0.01), but increased in group I from 43 +/- 8 mm to 46 +/- 9 mm (p less than 0.05). Mitral EF slope increased from 15 +/- 11 mm/sec to 52 +/- 20 mm/sec (p less than 0.001) after commissurotomy, and decreased from 136 +/- 61 mm/sec to 66 +/- 30 mm/sec (p less than 0.05) after annuloplasty. However, the postoperative means were subnormal in these subgroups. Paradoxical or hypokinetic septal motion occurred in 5/71 (7%) before and 50/71 (70%) after operation. We conclude that: 1) partial normalization of cardiac dimensions and subnormal mitral EF slopes shortly after mitral valve surgery suggest a residual pressure gradient across the mitral valve as well as partial irreversibility of the heart after longstanding mechanical overloading, and 2) postoperative abnormal septal motion, which may be caused by pericardiotomy, can occur after any type of open heart surgery.