Risk of osteoporosis and fracture in victims with burn injury

Osteoporosis is a well-known bone disorder affecting people worldwide. Patients with osteoporosis have an increased risk of bone fracture. This study provides new information on the risk of developing osteoporosis post burn injury and the risk of fracture among those with osteoporosis developed.

INTRODUCTION

The relationship between burn injury and hip fracture risk is unclear. Population-based evaluation on relationships between burn injury and osteoporosis development and subsequent fractures is limited. We conducted a retrospective cohort study as the investigation.

METHODS

From the insurance data of Taiwan, we established a cohort of 43,532 patients with a burn injury in 2000-2012 and a comparison cohort of 174,124 individuals without such an injury, frequency matched by sex, age, and diagnosis date. Both cohorts were followed up to the end of 2013 to evaluate the occurrence of osteoporosis and hip fracture.

RESULTS

The incidence of osteoporosis was greater in the burn cohort than in the comparison cohort (6.40 vs. 4.75 per 1,000 person-years) with an adjusted IRR of 1.35 (95% confidence interval = 1.32-1.39). The incidence rates in both cohorts were greater in women than in men, increased with age, income, and Charlson comorbidity index. Patients with burns involving 20%-49% of total body surface area and with burns confined to the lower/upper limbs had the greatest incidence rates, 8.32 and 8.58 per 1,000 person-years, respectively. Osteoporosis incidence increased further to 22.7 per 1,000 person-years for burn victims with comorbid diabetes. The risk of fracture was over five-fold greater for burn victims with osteoporosis developed than for comparisons without osteoporosis.

CONCLUSION

Patients who have a burn injury deserve prevention intervention to reduce the risk of osteoporosis and fracture.

Hip fracture risk in patients with burn injury: a retrospective cohort study in Taiwan

This work aimed to evaluate the hip fracture risk for patients with burn injury. A total of 16,430 patients with burn injury had an adjusted hazard ratio of 1.54 to encounter a hip fracture, compared with controls without the injury. These results encourage future studies focusing on mechanisms leading to fracture associated with burn injury.

INTRODUCTION

The relationship between burn injury and hip fracture risk is unclear. We conducted a retrospective cohort study to investigate this relationship.

METHODS

From insurance data of Taiwan, we identified a cohort with 16,430 burn patients in 2000-2010 and a comparison cohort of 65,716 persons without the history of burn, frequency matched by sex, age, and diagnosis date. Both cohorts were followed up to the end of 2011 to evaluate the risk of hip fracture.

RESULTS

Patients with burn injury were 1.62-fold more likely than comparisons to encounter a hip fracture (6.95 vs. 4.28 per 1000 person-years), with an adjusted hazard ratio (aHR) of 1.54 (95% confidence interval (CI) = 1.40-1.68). The fracture incidence increased with age and is slightly greater for women than for men in both cohorts. The fracture risk was greater for patients with burn in the eyes, face, and head with an incidence of 7.14 per 1000 person-years, or an aHR of 2.09 (95% CI = 1.53, 2.86). Diabetes and osteoporosis were also associated with an increased hip fracture risk.

CONCLUSION

Burn injury is associated with an increased risk of hip fracture. Diabetes and osteoporosis are associated with an enhanced risk.

AIM1 and LINE-1 epigenetic aberrations in tumor and serum relate to melanoma progression and disease outcome

Aberrations in the methylation status of non-coding genomic repeat DNA sequences and specific gene promoter region are important epigenetic events in melanoma progression. Promoter methylation status in LINE-1 and Absent in melanoma-1(AIM1;6q21) associated with melanoma progression and disease outcome was assessed. LINE-1 and AIM1 methylation status was assessed in paraffin-embedded archival tissues(PEAT)(n=133) and melanoma patients’ serum(n=56). LINE-1 U-Index(hypomethylation) and AIM1 were analyzed in microdissected melanoma PEAT sections. The LINE-1 U-Index of melanoma(n=100) was significantly higher than that of normal skin(n=14) and nevi(n=12)(P=0.0004). LINE-1 U-Index level was elevated with increasing AJCC stage(P<0.0001). AIM1 promoter hypermethylation was found in higher frequency(P=0.005) in metastatic melanoma(65%) than in primary melanomas(38%). When analyzed, high LINE-1 U-Index and/or AIM1 methylation in melanomas were associated with disease-free survival(DFS) and overall survival(OS) in Stage I/II patients (P=0.017, 0.027; respectively). In multivariate analysis, melanoma AIM1 methylation status was a significant prognostic factor of OS(P=0.032). Furthermore, serum unmethylated LINE-1 was at higher levels in both stage III(n=20) and stage IV(n=36) patients compared to healthy donors(n=14)(P=0.022). Circulating methylated AIM1 was detected in patients’ serum and was predictive of OS in Stage IV patients (P=0.009). LINE-1 hypomethylation and AIM1 hypermethylation have prognostic utility in both melanoma patients’ tumors and serum.

A bio-inspired two-layer multiple-walled carbon nanotube-polymer composite sensor array and a bio-inspired fast-adaptive readout circuit for a portable electronic nose

We report a fully integrated, portable, battery-operated electronic nose system comprising a bio-inspired two-layer multiple-walled carbon nanotube (MWNT)-polymer composite sensor array, a bio-inspired fast-adaptive readout circuit, and a microprocessor embedded with a pattern recognition algorithm. The two-layer MWNT-polymer composite sensor is simple to operate, and the membrane quality can be easily controlled. These two-layer membranes have improved sensitivity and stability. The fast-adaptive readout circuit responds to the sensor response, while tuning out the long-term constant background humidity, temperature, and odors. This portable electronic nose system successfully classified four complex alcohol samples 40 times for each sample; these samples were sake, sorghum liquor, medical liquor, and whisky.

Estimations of fiber Bragg grating parameters and strain gauge factor using optical spectrum and strain distribution information

An inverse approach based on an optimization technique is proposed to characterize a fiber Bragg grating (FBG) and the strain gauge factor (GF) when the FBG is bonded on a structure. By bonding an FBG on a substrate and simply straining this FBG into a chirped fiber Bragg grating with a predesignated strain, the proposed method, based on an optimization technique, can be used to reconstruct seven parameters of the FBG from the corresponding reflective spectrum. The parameters identified are the length of an FBG, the grating period, the average refractive index, the index modulation, the apodization coefficient, the starting point bonded on the plate, and the strain GF. The information from the predesignated strain, as well as the measured reflective spectrum, is used as the objective function during the optimal search. As a result, the design sensitivity for the optimal search is much improved compared with the design sensitivity when only the reflective spectrum is used. In particular, the strain GF, which depends on the adhesive, the bonding layer characteristics, etc., can be determined in order to provide a reference for an FBG used as a strain sensor. Results from numerical simulations and experiments show that seven parameters of an FBG can be obtained accurately and efficiently.

Peptide nucleic acid clamp PCR: a novel K-ras mutation detection assay for colorectal cancer micrometastases in lymph nodes

Inaccurate staging of colorectal cancer (CRC) has been attributed to the failure to detect lymph node metastases by conventional pathology. We have previously reported the use of lymphatic mapping to accurately identify those lymph nodes most likely to harbor micrometastatic disease and permit focused pathologic examination. Mutation of K-ras allele at codons 12 or 13 occurs frequently in early stages of CRC development. The purpose of our study was to assess sentinel lymph nodes (SLN) for occult CRC micrometastases using a unique peptide nucleic acid (PNA) clamp PCR assay specific for K-ras mutations. Seventy-two paraffin-embedded primary CRC and paired SLN were evaluated by PNA clamp PCR for K-ras mutations. Thirty primary tumors (42%) were positive for K-ras mutations, and in 5 of these cases the SLN were positive for metastases by Hematoxylin and Eosin staining. PNA clamp PCR identified occult metastases in an additional 6 patients, upstaging 24% of K-ras positive primary CRCs (p = 0.014). No K-ras mutations were detected among the 20 noncancer lymph nodes assessed. This study demonstrates the utility, specificity and sensitivity of PNA clamp PCR assay in identifying occult micrometastases in the SLN of CRC patients by single-base mutation analysis.

Prediction of disease outcome in melanoma patients by molecular analysis of paraffin-embedded sentinel lymph nodes

PURPOSE

A significant number of patients who develop recurrence after a histopathologically negative sentinel lymph node (SLN) biopsy will demonstrate occult metastases on re-evaluation of the SLNs with serial sectioning and immunohistochemistry. Reverse transcriptase polymerase chain reaction (RT-PCR) has been evaluated to improve disease staging and avoid false-negative findings in fresh or frozen-section SLNs. The purpose of this study was to develop a multimarker RT-PCR assay for assessing melanoma patients' archived paraffin-embedded (PE) SLNs.

PATIENTS AND METHODS

Archived PE histopathologically positive (n = 37) and negative (n = 40) SLNs from patients with primary melanoma were analyzed using a semiquantitative multimarker RT-PCR assay.

RESULTS

Marker expression in histopathologically positive and negative SLNs were as follows: 89%, 92%, 35%, and 43% (positive) and 40%, 33%, 5%, and 13% (negative) for tyrosinase, melanoma antigen recognized by T cells-1, tyrosinase-related protein-1, and tyrosinase-related protein-2, respectively. Twenty-five percent of histopathologically negative SLN patients were upstaged using at least two markers. Of these, 80% developed a recurrence. Furthermore, at a median follow-up of 55 months, patients with histopathologically negative SLNs who expressed zero or one marker had a significantly improved disease-free (P <.002) and overall (P <.03) survival versus those expressing two or more markers.

CONCLUSION

These findings demonstrate the feasibility of a multimarker RT-PCR assay for evaluating archived PE SLNs. More significantly, identification of molecular risk factors can be detected in histopathologically negative SLNs for distinguishing early-stage melanoma patients with a worse prognosis.

Involvement of nuclear factor-kappaB in lipoteichoic acid-induced cyclooxygenase-2 expression in RAW 264.7 macrophages

We have investigated the role of protein kinase C (PKC) and nuclear factor-kappaB (NF-kappaB) in cyclooxygenase-2 (COX-2) expression caused by Staphylococcus aureus lipoteichoic acid in RAW 264.7 macrophages. A phosphatidylcholine-phospholipase C (PC-PLC) inhibitor (D-609) and a phosphatidylinositol-phospholipase C (PI-PLC) inhibitor (U-73122) attenuated lipoteichoic acid-induced COX-2 expression, while a phosphatidate phosphohydrolase inhibitor (propranolol) had no effect. Two PKC inhibitors (Go 6976 and Ro 31-8220) and the NF-kappaB inhibitor, pyrrolidine dithiocarbamate (PDTC), also attenuated lipoteichoic acid-induced COX-2 expression. Lipoteichoic acid resulted in a decrease in PKC activity in the cytosol and an increase in PKC activity in membranes. The lipoteichoic acid-induced translocation of p65 NF-kappaB from the cytosol to the nucleus was inhibited by D-609, U-73122, Go 6976, Ro 31-8220, and PDTC, but not by propranolol. The results suggested that lipoteichoic acid might have activated PC-PLC and PI-PLC to induce PKC activation, which in turn initiated NF-kappaB activation, and finally induced COX-2 expression in RAW 264.7 macrophages.

Molecular lymphatic mapping of the sentinel lymph node

Intraoperative lymphatic mapping to identify the sentinel lymph node (SLN) has significantly changed the management of regional lymph node basin of patients with various types of solid tumors such as melanoma and breast cancer. The procedure has improved the diagnosis of micrometastasis in the regional tumor-draining lymph nodes by providing a focused histopathological assessment of select lymph nodes most likely to harbor occult disease. Blue dye and/or radioisotopes are efficient mapping agents but the lack of accurate methods to quantify their presence and the potential for dissolution and decay, respectively, throughout time limit their role as reliable markers for identifying a sentinel node from additional secondary lymph nodes that may be either blue and/or radioactive to some degree. A consistently durable marker is needed that can be introduced during surgery and successfully quantitated among tumor-draining lymph nodes to permit a more accurate assessment of hierarchical organization. This may be of particular importance in retrospective analysis of archival tissues as there are no inherent markers to denote the SLN from successive echelon nodes. A procedure of molecular lymphatic mapping (MLM) was developed in a rat model to label the SLN preoperatively with rice gene DNA containing plasmid or linear rice DNA fragment (rDNA). The MLM efficiency was demonstrated by polymerase chain reaction (PCR) detection of the molecular marker in both frozen and paraffin-embedded SLN; 1.25 micro g of rDNA injected with blue dye could be reproducibly detected by PCR. The MLM procedure was validated in a rat breast tumor model with lymph node metastasis. The procedure was successful in permanently labeling and identifying by PCR both frozen and paraffin-embedded SLN. MLM in conjunction with a conventional mapping agent can be used as a valuable asset for molecular assessment of the SLN and retrospective analysis of paraffin-embedded specimens.

Overexpression of beta 1,4N-acetylgalactosaminyl- transferase mRNA as a molecular marker for various types of cancers

OBJECTIVE

To determine GalNAcT mRNA expression in human carcinoma cell lines and primary tumor tissues. Assessment of the potential use of GalNAcT mRNA as a molecular marker for detection of metastatic cancer cells in the peripheral blood of patients with hepatocellular carcinoma.

METHODS/RESULTS

We investigated GalNAcT mRNA expression in various human cancer cell lines and primary cancer tissues using RT-PCR assay for GalNAcT mRNA. The expression of GalNAcT mRNA was detected in 25 of 26 cancer cell lines tested and in the majority of primary tumors from different organs: 8 of 10 colon cancers, 9 of 9 breast cancers, 11 of 12 esophageal cancers, 14 of 14 gastric cancers, 4 of 18 pancreatic cancers, 6 of 12 biliary tract cancers, 17 of 18 hepatocellular carcinomas and 13 of 14 lung cancers. Semi-quantitative analysis with duplex RT-PCR showed that the amount of the GalNAcT mRNA was enhanced in cancer tissues as compared to the surrounding cancer-free tissues. Blood specimens of 5 of 14 patients with hepatocellular carcinoma were positive for GalNAcT mRNA, all of whom developed recurrent disease in less than 24 months. Peripheral blood samples of 30 normal subjects were negative for GalNAcT mRNA.

CONCLUSION

Our results suggest that the RT-PCR assay for GalNAcT mRNA could be a potentially useful molecular marker for detecting cancer dissemination in blood circulation of patients with malignancy.

Detection of occult metastatic breast cancer cells in blood by a multimolecular marker assay: correlation with clinical stage of disease

Currently, molecular markers offer the unique opportunity to identify occult metastasis in early stage cancer patients not otherwise detected with conventional staging techniques. To date, well-characterized molecular tumor markers to detect occult breast cancer cells in blood are limited. Because breast tumors are heterogeneous in tumor marker expression, we developed a "multimarker" reverse transcription-PCR assay combined with the highly sensitive electrochemiluminescence automated detection system. Breast cancer cell lines (n = 7), primary breast tumors (n = 25), and blood from normal donors (n = 40) and breast cancer patients [n = 65; American Joint Committee on Cancer (AJCC) stages I-IV] were assessed for four mRNA tumor markers: beta-human chorionic gonadotropin (beta-hCG), oncogene receptor (c-Met), beta 1-->4-N-acetylgalactosaminyl-transferase, and a tumor-associated antigen (MAGE-A3). None of the tumor markers were expressed in any normal donor bloods. Breast cancer cell lines and primary breast tumors expressed beta-hCG, c-Met, beta 1-->4-N-acetylgalactosaminyl-transferase, and MAGE-A3 mRNA. Of the 65 breast cancer patient blood samples assessed, 2, 3, 15, 49, and 31% expressed 4, 3, 2, 1, and 0 of the mRNA tumor markers, respectively. At least two markers were expressed in 20% of the blood specimens. The addition of a combination of markers enhanced detection of systemic metastasis by 32%. In patient blood samples, the MAGE-A3 marker correlated significantly with tumor size (P = 0.0004) and AJCC stage (P = 0.007). The combination of beta-hCG and MAGE-A3 mRNA markers correlated significantly with tumor size (P = 0.04), and the marker combination c-Met and MAGE-A3 showed a significant correlation with tumor size (P = 0.005) as well as AJCC stage (P = 0.018). A multimarker reverse transcription-PCR assay that correlates with known clinicopathological prognostic parameters may have potential clinical utility by monitoring tumor progression with a blood test.

Screw-in atrial lead in a sick sinus syndrome patient with anomalous inferior vena cava

Anomalous inferior vena cava without intracardiac anomaly is an unusual condition. Herein, we report a 48-year-old female with left-sided inferior vena cava and azygous continuation. accompanied by sick sinus syndrome. This anomaly resulted in difficulty in implanting a traditional hook-on atrial lead. Atrial lead dislodgment occurred repeatedly soon after implanting the pacemaker because of an anomalous zygous vein draining into the superior vena cava, making a giant connection with the right atrium, thus eliminating the space of the atrial appendage for lead lodgment. Finally, we attempted to utilize a screw-in atrial lead in this patient and she is currently doing well. We therefore suggest that a screw-in atrial lead should be taken into account for such patients in order to obtain a stable fixation.

Molecular detection of metastatic melanoma cells in cerebrospinal fluid in melanoma patients

Melanoma frequently metastasizes to the central nervous system (CNS). The diagnosis of CNS metastases typically is made following the onset of clinical symptoms. Thus, more sensitive diagnostic approaches are needed to identify subclinical CNS metastases. Currently, standard cytologic analysis of the cerebrospinal fluid (CSF) is limited by its poor sensitivity. A more sensitive assay was therefore developed using multiple reverse transcriptase-polymerase chain reaction (RT-PCR) markers. CSF was collected and assessed by RT-PCR for three known melanoma-associated markers (MAGE-3, MART-1, and tyrosinase) to detect occult metastatic melanoma cells in the CSF of 37 American Joint Committee on Cancer (AJCC) stage IV melanoma patients. Cytologic analysis of CSF was performed on all patients, and immunohistochemistry (IHC) analysis was performed on 33 CSF samples using anti-S100 and anti-HMB-45 antibodies. Only one patient (3%) had tumor-positive CSF cytology and IHC upon entry into the study, whereas 12 patients (32%) were positive for at least one RT-PCR marker. The correlation between CSF RT-PCR positivity of MART-1 and/or MAGE-3 and the development of CNS metastases at 3 mo was significant (p = 0.04). Fifteen of 37 patients (41%) had either positive MRI and/or positive RT-PCR results. Multimarker RT-PCR is more informative and sensitive than cytology/IHC in assessing the CSF of melanoma patients.

Ganglioside GM2/GD2 synthetase mRNA is a marker for detection of infrequent neuroblastoma cells in bone marrow

GalNAcbeta1-4(NeuAcalpha2-3)Galbeta1-4Glcbeta1-Cer (GM2)/GalNAcbeta1-4(NeuAcalpha2-8NeuAcalpha2-3)Galbeta1-4Glcbeta1-1Cer (GD2) synthetase [beta-1,4-N-acetyl-galactosaminyl transferase (GalNAc-T)] mRNA, which encodes a key glycosyltransferase for ganglioside GD2 synthesis, was assessed as a molecular marker for detecting metastatic neuroblastoma cells in bone marrow (BM). GalNAc-T mRNA expression by neuroblastoma cell lines (n = 15), primary untreated neuroblastoma tumors (n = 29), morphologically normal BM (n = 22), peripheral blood stem cells (n = 10) from patients with cancers other than neuroblastoma, and blood mononuclear cells from normal donors (n = 17) was assessed by using reverse transcriptase-polymerase chain reaction (RT-PCR) and electrochemiluminescence detection assay (RT-PCR/ECL). BM harvested from 15 neuroblastoma patients was tested before and after ex vivo immunomagnetic bead purging, and results were compared to immunocytological analysis of the same specimens. All neuroblastoma cell lines (mean, 653 x 10(3) ECL units) and primary tumors (mean, 683 x 10(3) ECL units) were positive for significant expression of GalNAc-T mRNA compared to normal blood and BM cells. The RT-PCR/ECL assay could detect GalNAc-T mRNA in 100 pg of total RNA, and in a mixture of one neuroblastoma cell among 10(7) normal BM or blood cells. Eight of 15 autologous BM cells harvested from patients with neuroblastoma had tumor cells detectable by immunocytology, and all 15 were positive for GalNAc-T mRNA. After ex vivo purging, none of the BM cells was immunocytology-positive, but six remained positive by the RT-PCR/ECL assay. GalNAc-T mRNA provides a specific and sensitive molecular marker for RT-PCR/ECL detection of infrequent neuroblastoma cells in BM.

Transcription factor LKLF is sufficient to program T cell quiescence via a c-Myc-dependent pathway

T lymphocytes circulate in a quiescent state until they encounter cognate antigen bound to the surface of an antigen-presenting cell. The molecular pathways that regulate T cell quiescence remain largely unknown. Here we show that forced expression of the lung Krüppel-like transcription factor (LKLF) in Jurkat T cells is sufficient to program a quiescent phenotype characterized by decreased proliferation, reduced cell size and protein synthesis and decreased surface expression of activation markers. Conversely, LKLF-deficient peripheral T cells produced by gene targeting showed increased proliferation, increased cell size and enhanced expression of surface activation markers in vivo. LKLF appeared to function, at least in part, by decreasing expression of the proto-oncogene encoding c-Myc. Forced expression of LKLF was associated with markedly decreased c-Myc expression. In addition, many effects of LKLF expression were mimicked by expression of the dominant-negative MadMyc protein and rescued by overexpression of c-Myc. Thus, LKLF is both necessary and sufficient to program quiescence in T cells and functions, in part, by negatively regulating a c-Myc--dependent pathway.

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.

Characterization of murine BATF: a negative regulator of activator protein-1 activity in the thymus

BATF belongs to the AP-1/ATF superfamily of transcription factors and forms heterodimers with Jun proteins to bind AP-1 consensus DNA. Unlike Fos/Jun heterodimers which stimulate gene transcription, BATF/Jun heterodimers are transcriptionally inert and inhibit biological processes that are associated with the overstimulation of AP-1 activity. Here, we describe the murine BATF cDNA and genomic clones and map the BATF locus to chromosome 12 D2-3. Using in situ hybridization of BATF mRNA, we show that BATF gene expression is highly restricted, with the most prominent signals detected in the thymus. BATF mRNA levels are regulated differentially during discrete stages of T cell development and are up-regulated following activation of T cells in the periphery. To demonstrate the impact of BATF on AP-1 activity in vivo, AP-1 luciferase reporter mice were crossed to transgenic mice overexpressing BATF exclusively in thymic T cells. Results show that elevated levels of BATF protein correlate with reduced transactivation by AP-1. Since the differential regulation of AP-1 activity is linked to key transitions in the developing immune system, our observations support a critical role for BATF in determining the overall level of AP-1 activity, and thus AP-1 target gene expression, in specific T cell subtypes.

Emerging new frontiers in cardiac pacing: cardiac pacing in heart failure

Indications for pacing have leapt beyond sinus node dysfunction and atrioventricular (AV) block. Pacing for the purpose of improving hemodynamics has become the prime subject of exploration. Several studies have reported hemodynamic and clinical improvement with bi-ventricular pacing and AV sequential pacing. Data is still pouring in from the various ongoing trials regarding the beneficial effects of these methods of pacing. This is especially true in a subset of patients with intractable heart failure. There are several indicators to identify these patients. Those who have intra-ventricular conduction defects and those who demonstrate hemodynamic improvement after temporary pacing are certainly the candidates who will benefit most from this new form of pacing. Prolonged PR interval or left bundle branch block with intractable heart failure also falls into this category. The rationale of pacing in heart failure is to correct the cardiac dysynchrony that occurs frequently in these patients. Cardiac dysynchrony can occur due to ineffective synchronization between atria and ventricles (AV dysynchrony) or due to lack of synchronization within the two ventricles (ventricular dysynchrony). This is overcome by AV sequential pacing or by multi chamber pacing using the coronary sinus as portal of entry of the electrode into the cardiac vein to pace the left ventricle. Pacing leads and generators have been designed to suit the new found methods of pacing. Clinical trials are in full swing to establish the efficacy of these methods.

The effects of aging on AV nodal recovery properties

The purpose of this study was to assess the changes of AV nodal recovery properties with aging. Although in children and young adults it was found that there were age dependent changes in their AV nodal recovery properties, in the older population this information was not available. In 92 subjects (aged 16-92 years) without AV nodal disease or dual AV nodal pathway physiology, their AV nodal recovery curves were studied by delivering premature atrial extrastimuli coupled to basic atrial beats during cardiac electrophysiological study. Data were analyzed using linear regression and curve-fitting techniques. Patients were grouped by age, group I < 40 years (n = 33), group II 40-59 years (n = 26), and group III > 60 years (n = 33). The results showed that the AV nodal recovery curve did not change significantly in the aging process except that the AV nodal effective refractory period had a positive correlation with increasing age. The latter was significantly increased in group III when compared to group I or group II. For this parameter, when patients whose AV nodal refractory period was limited by the atrial refractory period were excluded, there was still a statistically significant increase in group III compared to group II (P < 0.05): group I (n = 27): 202+/-42 ms; group II (n = 17): 197+/-26 ms; and group III (n = 17): 224+/-46 ms. The results suggest that the AV nodal recovery curve remains unchanged once it reaches adulthood, with the exception that the nodal effective refractory period becomes slightly longer after age 60.

Low prevalence of coronary arterial disease in Chinese adults with mitral stenosis

BACKGROUND

We attempted to evaluate the prevalence of coronary artery disease in Chinese adults with severe rheumatic mitral stenosis.

METHODS

We prospectively performed coronary angiography in 119 consecutive Chinese patients older than 40 years old (mitral valve area less than 1.5 cm2) who were about to undergo balloon mitral commissurotomy for significant rheumatic mitral stenosis. The exclusion criteria were the presence of left atrial cavitary thrombi or mitral regurgitation greater than grade 3.

RESULTS

There were 32 men (26%) and 87 women (74%) with a mean age of 55 +/- 9.7 years (ranging from 40 to 78). Ninety-two patients (77%) were in atrial fibrillation. The prevalence of risk factors for atherosclerotic cardiovascular disease were hypertension (22%), diabetes mellitus (4%), hypercholesterolemia > or = 240 mg/dL (5%), hypertriglyceridemia > or = 150 mg/dL (13%), and cigarette use (7%). Coronary artery disease on angiography was defined as stenosis of more than 50% of the luminal diameter. We found that only 2 patients (1.7%) had coronary artery disease.

CONCLUSION

The prevalence of coronary artery disease was much lower than in previous reports, some of which, however, had already pointed out the relatively low prevalence of coronary artery disease in rheumatic mitral disease. The definite mechanisms require further study.

Localizing ventricular tachycardia through entrainment

Area(s) of slow conduction are thought to be present within the reentry circuit of most clinically important ventricular tachycardia (VT). To prevent recurrence after ablation of VT late after myocardial infarction, it is desirable to localize and destroy area(s) of slow conduction "critical link" within the reentry circuit. Conventionally, they may be identified by endocardial catheter mapping, continuous electrical activity, mid-diastolic potentials, earliest endocardial activation, pace-mapping etc. However, none of these methods are very specific. Entrainment method may be used to localize the slow conduction zone of reentrant VT. Concealed entrainment is consistent with pacing at a site in the reentry circuit but may also occur at some "bystander" sites that are close to the reentry circuit but are not participating in the circuit itself. During pacing at the slow conduction area of the reentry circuit, the stimulus to QRS (S-QRS) interval should equal the electrogram to QRS (EG-QRS) interval during VT. Similarly the post-pacing interval (PPI) approximates the tachycardia cycle length. During pacing at bystander sites, the S-QRS interval may be greater, less than or equal to the EG-QRS interval, depending on the conduction time from the bystander site to the circuit. The PPI, however, always exceed the tachycardia cycle length. In conjunction with concealed entrainment, the use of diastolic potential, double potentials and continuous electrical activity enhances the prediction of radiofrequency termination of post-infarction VT.

Determination of 1,3-, 1,6-, 1,8-dinitropyrene and 1-nitropyrene in airborne particulate by column liquid chromatography with electrochemical detection

Nitrated polycyclic aromatic hydrocarbons (NPAHs) in airborne particulate were determined by column liquid chromatography with electrochemical detection. NPAHs were extracted ultrasonically prior to being injected into the separation system. A reversed-phase C18 column was used to separate the NPAHs with an aqueous eluent containing acetonitrile and sodium monochloroacetate as buffer. Calibration graphs were linear with very good correlation coefficients (r>0.999) and the detection limits were ca. 20 pg for all analytes. The proposed method provides a relatively simple and convenient procedure for determining the NPAHs in airborne particulate.

Brugada syndrome without mutation of the cardiac sodium channel gene in a Taiwanese patient

We describe a 45-year-old Taiwanese man with specific features of Brugada syndrome but no clinical features of structural heart disease. He was successfully treated with an implantable cardioverter-defibrillator. His electrocardiogram (ECG) patterns changed intermittently. Alpha-adrenoceptor stimulation and beta-adrenoceptor blockade augmented the characteristic ST-segment elevation, whereas alpha-adrenoceptor blockade and beta-adrenoceptor stimulation mitigated the ST-segment elevation. Intravenous procainamide administration did not aggravate ST-segment elevation when ECG had shown coved ST elevation in the right precordial leads. Molecular study did not reveal the same mutations in the cardiac sodium channel gene (SCN5A) as previously reported in Brugada syndrome. This case demonstrates the genetic heterogeneity of SCN5A in Brugada syndrome.

Right pneumothorax resulting from an endocardial screw-in atrial lead

Right pneumothorax complicated by an endocardial atrial lead has never been reported. Herein, we report on a small-build 79-year-old Taiwanese woman who suffered from complete AV block and underwent dual-chamber permanent pacemaker implantation. An active fixation screw-in atrial lead was chosen. The procedure was complicated by right pneumothorax associated with atrial perforation. Since simple measurements of the implantation parameters could not be used to predict the occurrence of perforation, great caution should be taken in to avoid overscrewing the atrial lead, and in scrutinizing the penetration depth of the helix of the lead under fluoroscopy.

Expression of the transcription factor lung Krüppel-like factor is regulated by cytokines and correlates with survival of memory T cells in vitro and in vivo

The transcription factor lung Krüppel-like factor (LKLF) is involved in naive T cell survival. Expression of LKLF is rapidly down-regulated upon T cell stimulation, raising the question of whether LKLF is reexpressed after activation, and what factors are required for such reexpression. Furthermore, the expression of LKLF in resting memory cells has not been determined. Here, we use the OT-I TCR transgenic mouse system to address these issues. LKLF was found to be reexpressed following culture of activated CD8 T cells in certain cytokines (IL-2, IL-7) but not others (IL-12) known to influence CTL development. Interestingly, induction of LKLF reexpression corresponded with long-term T cell survival and development of memory T cell phenotype. Furthermore, using OT-I cells stimulated in vivo, we demonstrated that Ag induced rapid LKLF down-regulation and that the factor is expressed by in vivo-derived memory T cells.

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.

Transcriptional regulation of T lymphocyte development and function

The development and function of T lymphocytes are regulated tightly by signal transduction pathways that include specific cell-surface receptors, intracellular signaling molecules, and nuclear transcription factors. Since 1988, several families of functionally important T cell transcription factors have been identified. These include the Ikaros, LKLF, and GATA3 zinc-finger proteins; the Ets, CREB/ATF, and NF-kappa B/Rel/NFAT transcription factors; the Stat proteins; and HMG box transcription factors such as LEF1, TCF1, and Sox4. In this review, we summarize our current understanding of the transcriptional regulation of T cell development and function with particular emphasis on the results of recent gene targeting and transgenic experiments. In addition to increasing our understanding of the molecular pathways that regulate T cell development and function, these results have suggested novel targets for genetic and pharmacological manipulation of T cell immunity.

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.

Transdermal delivery of sodium nonivamide propionate by iontophoresis

The aim of this study was to investigate the transdermal iontophoresis of a newly designed capsaicin derivative, sodium nonivamide propionate (SNP). The iontophoretic permeation of SNP from various pH buffers increased following the decrease of pH values. This trend was consistent with that of sodium nonivamide acetate (SNA) which is another synthetic analogue of capsaicin. However, the iontophoretic permeability of SNP was much lower than that of SNA. SNP was also delivered iontophoretically from hydrogel formulations. It is suggested that ionizable polymers should be avoided for iontophoretic delivery to maintain good penetration capacity of drugs. Both nonionic cellulose polymers of methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC) showed higher iontophoretic flux for SNP than the others did. Furthermore, the flux of SNP leveled off with an increase in the amount of polymers in hydrogel, indicating that the viscosity of vehicles plays an important role in the permeation of SNP. Comparing the various iontophoretic application modes, the discontinuous on/off cyclic mode showed higher penetration capacity than did the continuous mode although they possessed the same electrical energy. Moreover, the desorption time of SNP from skin was approximately 20 min which was longer than that of SNA.

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.

Assessment of messenger RNA of beta 1-->4-N-acetylgalactosaminyl-transferase as a molecular marker for metastatic melanoma

Gangliosides GM2 [GalNAc beta 1-4(NeuAc alpha 2-3)Gal beta 1-4Glc beta 1-1Cer] and GD2 [GalNAc beta 1-4(NeuAc alpha 2-8NeuAc alpha 2-3)Gal beta 1-4Glc beta 1-1Cer] are cell surface tumor-associated antigens and have been demonstrated to be important markers of human malignant melanoma progression. Expression of these glycolipid antigens on melanoma tissues can be assessed by immunohistochemistry or biochemical analysis. These methodologies, however, are not logistically practical or sensitive for testing metastatic melanoma cells in blood or in tissue biopsies. In the present study, we hypothesized that the enzyme involved in GM2 and GD2 synthesis, beta 1-->4-N-acetylgalactosaminyltransferase (beta 1-->4GalNac-T), can be a useful marker for detection of occult metastatic melanoma. A reverse transcription PCR and Southern blot assay to detect beta 1-->4GalNac-T mRNA expression was developed. Beta 1-->4GalNac-T mRNA was detected in all 13 melanoma cell lines tested. Metastatic melanoma of lymph nodes and different organ sites expressed beta 1-->4GalNac-T mRNA at various levels. Detection sensitivity of the reverse transcription PCR assay was 1 ng of total RNA extracted from tumor specimens and approximately 5 melanoma cells in 20 million normal donor peripheral blood lymphocytes. In assessment of blood from 126 melanoma patients, beta 1-->4GalNac-T mRNA was more frequently found in advanced-stage melanomas and in patients showing more aggressive tumor progression. Normal donor blood samples (n = 37) were all negative for beta 1-->4GalNac-T mRNA expression. These results suggest that beta 1-->4GalNac-T mRNA is a promising molecular marker for detecting melanoma cells, characterizing antigen expression, and monitoring tumor progression.

Prognostic implications of p53 overexpression in cutaneous melanoma from sun-exposed and nonexposed sites

BACKGROUND

There is increasing evidence that mutations in the p53 tumor suppressor gene are among the most common genetic alterations in human malignancies. Because ultraviolet light can induce specific p53 mutations and is linked to the development of skin cancers, this study was done to determine the significance of p53 protein (p53p) overexpression in melanomas originating at different cutaneous sites varying in frequency of sunlight exposure.

METHODS

Sixty-three paraffin embedded primary and metastatic melanoma biopsy specimens from 61 patients were deparaffinized and stained with the mouse monoclonal antibody DO-1 to wild-type and mutant p53p. Twenty-eight specimens were from primary tumors and 35 specimens were from lymph node, subcutaneous, or visceral metastases. The chi-square test was used to assess the significance of p53p overexpression, and the Cox proportional hazards model was used to estimate the impact of p53p overexpression on survival.

RESULTS

Of the 61 patients studied, 37 had primary cutaneous melanomas arising on chronically sun-exposed head and neck sites, 12 patients on intermittently exposed extremity sites, and 12 patients on rarely exposed trunk sites. Thirteen of the 63 primary or metastatic specimens (21%) overexpressed p53p. Overexpression of p53p was not related to patient gender or age, anatomic site of the primary tumor, Clark level, or Breslow thickness. However, those patients with p53p positive primary tumors or metastases had significantly better survival than those determined to be negative for p53p overexpression (P = 0.045). The median survival was 152.4 months for p53p positive patients versus 55.7 months for p53p negative patients. The risk ratio of dying from melanoma was 0.32 for patients with tumor specimens overexpressing p53p.

CONCLUSIONS

In this study, p53p overexpression was infrequent in paraffin embedded melanoma specimens and independent of the primary melanoma's anatomic site. Although p53p overexpression was not related to other prognostic features of primary or metastatic lesions, it was associated with a significantly improved survival in this group of melanoma patients.

The LKLF transcription factor is required for normal tunica media formation and blood vessel stabilization during murine embryogenesis

The transcriptional programs that regulate blood vessel formation are largely unknown. In this paper, we examine the role of the zinc finger transcription factor LKLF in murine blood vessel morphogenesis and homeostasis. By in situ hybridization and immunohistochemistry, we show that LKLF is expressed as early as embryonic day 9.5 (E9.5) in vascular endothelial cells throughout the developing mouse embryo. To better understand the function of LKLF, we used homologous recombination in embryonic stem (ES) cells to generate LKLF-deficient (LKLF-/-) mice. Both angiogenesis and vasculogenesis were normal in the LKLF-/- mice. However, LKLF-/- embryos died between E12.5 and E14.5 from severe intra-embryonic and intra-amniotic hemorrhaging. This bleeding disorder was associated with specific defects in blood vessel morphology. Umbilical veins and arteries in the LKLF-/- embryos displayed an abnormally thin tunica media and aneurysmal dilatation before rupturing into the amniotic cavity. Similarly, vascular smooth muscle cells in the aortae from the LKLF-/- animals displayed a cuboidal morphology and failed to organize into a compact tunica media. Consistent with these findings, electron microscopic analyses demonstrated endothelial cell necrosis, significant reductions in the number of vessel-wall pericytes and differentiating smooth muscle cells, and decreased deposition of extracellular matrix in the LKLF-/- vessels. Despite these defects, in situ hybridization demonstrated normal expression of platelet-derived growth factor B, Tie1, Tie2, transforming growth factor beta, and heparin-binding epidermal growth factor in the vasculature of the LKLF-/- embryos. Therefore, LKLF defines a novel transcriptional pathway in which endothelial cells regulate the assembly of the vascular tunica media and concomitant vessel wall stabilization during mammalian embryogenesis.

LKLF: A transcriptional regulator of single-positive T cell quiescence and survival

Mature single-positive (SP) T lymphocytes enter a "resting" state in which they are proliferatively quiescent and relatively resistant to apoptosis. The molecular mechanisms regulating this quiescent phenotype were unknown. Here it was found that the expression of a Kruppel-like zinc finger transcription factor, lung Kruppel-like factor (LKLF), is developmentally induced during the maturation of SP quiescent T cells and rapidly extinguished after SP T cell activation. LKLF-deficient T cells produced by gene targeting had a spontaneously activated phenotype and died in the spleen and lymph nodes from Fas ligand-induced apoptosis. Thus, LKLF is required to program the quiescent state of SP T cells and to maintain their viability in the peripheral lymphoid organs and blood.

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.

GATA4 transcription factor is required for ventral morphogenesis and heart tube formation

Previous studies have suggested that the GATA4 transcription factor plays an important role in regulating mammalian cardiac development. In the studies described in this report we have used gene targeting to produce GATA4-deficient mice. Homozygous GATA4-deficient (GATA4-/-) mice died between 8.5 and 10.5 days post coitum (dpc). GATA4-/- embryos displayed severe defects in both rostral-to-caudal and lateral-to-ventral folding, which were reflected in a generalized disruption of the ventral body pattern. This resulted in the defective formation of an organized foregut and anterior intestinal pore, the failure to close both the amniotic cavity and yolk sac, and the uniform lack of a ventral pericardial cavity and heart tube. Analysis of cardiac development in the GATA4-/- mice demonstrated that these embryos developed splanchnic mesoderm, which differentiated into primitive cardiac myocytes that expressed contractile proteins. However, consistent with the observed defect in ventral morphogenesis, these GATA4-/- procardiomyocytes failed to migrate to the ventral midline to form a linear heart tube and instead formed aberrant cardiac structures in the anterior and dorsolateral regions of the embryo. The defect in ventral migration of the GATA4-/- procardiomyocytes was not cell intrinsic because GATA4-/- cardiac myocytes and endocardial cells populated the hearts of GATA4-/- -C57BL/6 chimeric mice. Taken together, these results demonstrated that GATA4 is not essential for the specification of the cardiac cell lineages. However, they define a critical role for GATA4 in regulating the rostral-to-caudal and lateral-to-ventral folding of the embryo that is needed for normal cardiac morphogenesis.

Similar time-dependent recovery property of fast and slow atrioventricular nodal pathways

The purpose of this study was to determine whether fast and slow atrioventricular (AV) nodal pathways have the same recovery property. AV nodal recovery property is studied by delivering atrial extrastimuli coupled to atrial beats and plotting nodal coupling intervals against nodal conduction time. In patients with dual pathways the resultant curves will include a fast to fast (F-F) and a fast to slow (F-S) pathway coupled curves. Although fast pathway recovery property can be represented by the former, slow pathway recovery property requires further assessment by studying slow to slow (S-S) pathways coupled curve. In 9 patients with dual pathways F-F, F-S, S-F, and S-S curves were obtained by pacing protocols. In 8 patients (control) without dual pathways, F-F curve and atrial extrastimuli coupled to a preceding slowly conducted fast pathway beat (also designated as S-F curve) were obtained. (1) The S-S curve had a similar time constant as the F-F curve. (2) Although the S-S curve was markedly shifted upward and leftward from the F-F curve, the degree of leftward and upward shifts of the S-S curve from the F-F curve were both close to the difference of the basic fast and slow pathway conduction time (a constant). (3) Although the effective refractory period of the fast pathway in dual pathway patients was longer than that of the control patients, the slow pathway effective refractory period when corrected was close to that of fast pathway in control patients. These results suggest that the fast and slow AV nodal pathways have a similar time-dependent recovery property.

Anticholinergic overdose induced torsade de pointes successfully treated with verapamil

An 18-year-old schizophrenic female was recently treated after overdosing on trihexyphenidyl, thioridazine and an unknown antidepressant. On presentation to a local hospital, she was cyanotic with dilatated pupils and in acute respiratory failure. She was intubated prior to transfer. While in our Emergency Department, she exhibited occasional premature ventricular contractions which later became intermittent torsade de pointes. As this was an anticholinergic overdose we infused sodium bicarbonate in an attempt to increase protein binding, hoping to decrease the concentration of toxic metabolites. We also tried to suppress the dysrhythmia by infusing magnesium. The potassium level was borderline low so a supplemental infusion was initiated. Defibrillation was attempted. To try to shorten the action potential duration by activating the K+ channel, an isuprel infusion was also attempted. All methods failed. The patient fluctuated between an irregular sinus rhythm with prolonged QT interval and pulseless torsade de pointes for almost 24 hours. At all times, she responded appropriately to pain. Finally we attempted blockade of the calcium channel using verapamil with dramatic results. Each single bolus (0.1 mg/kg) successfully converted the patient back to sinus rhythm for some 15-20 minutes before the torsade recurred. After the initiation of a continuous verapamil infusion (0.005 mg/kg/hr), the patient remained in stable sinus rhythm. Verapamil proved highly effective in this patient with an anticholinergic overdose induced dysrhythmia.

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.

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.

Living biosensors for the management and manipulation of microbial consortia

The increasing interest in microbial ecology has resulted in the creation of new tools for the study of complex microbial interactions. Bioreporter genes are particularly useful because they provide a means of determining gene activity. Most bioreporter genes utilize a biochemical assay requiring destructive sampling of the microbial consortium, but lux bioreporter genes produce visible light when active. The measurement of light is rapid, sensitive, and quantifiable, and background signal is usually absent. The usefulness of lux bioreporters is shown in several examples that demonstrate the unique attributes of this bioreporter. Despite some limitations, bioluminescence has proved to be a useful bioreporter under both laboratory and field conditions. Technological developments are discussed that have the potential to increase the number of bioreporter genes.

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.

Imaging of multiple coronary artery fistulas to right ventricle by transthoracic and transesophageal echocardiography

A 20-year-old woman presented with extremely rare multiple coronary artery fistulas with left circumflex and right coronary arteries as the feeding vessels and two distinct sites of drainage into the posterior wall of the right ventricle near the apex in close proximity. The large left fistula was well depicted by transthoracic echocardiography, whereas the transesophageal approach better delineated part of the smaller right fistula.

A comparison between intravenous streptokinase and tissue plasminogen activator with early intravenous heparin in acute myocardial infarction

To compare the effects of two thrombolytic agents, streptokinase and recombinant tissue-type plasminogen activator (rTPA) with early heparinization, on left ventricular function, coronary patency and reinfarction rates, bleeding complications, and short- and long-term mortality, we studied 122 patients with acute myocardial infarction prospectively. All of them fulfilled the standard criteria for thrombolytic therapy. One group (n = 63) received 1,500,000 units of streptokinase over 1 hour, and one group (n = 59) received 100 mg of rTPA over 3 hours. Baseline data showed no significant differences between the streptokinase and rTPA groups. Results of predischarge studies 10 to 14 days after infarction revealed that there was no difference in left ventricular ejection fraction between the two groups (48.3% in the streptokinase group and 49.9% in the rTPA group; p = 0.67). The patency rate of the infarct-related artery tended to be higher in the rTPA group compared with the streptokinase group (77% vs 57%, p = 0.19). In-hospital spontaneous bleeding occurred after streptokinase in seven patients (11.1%) and after rTPA in eight (13.6%; p = 0.89). One patient had intracranial bleeding after rTPA and died 13 hours later. The early mortality rate within 30 days of acute myocardial infarction was 5 of 63 (7.9%) for the streptokinase group and 2 of 59 (3.4%) for the rTPA group (p = 0.49). During the 19.3-month follow-up period, reinfarction occurred in seven patients (11%) in the streptokinase group and in three (5%) in the rTPA group (p = 0.3). The mortality rates were 10 of 63 (16%) and 3 of 59 (5%), respectively (p = 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)