Peptide Binder to Glypican-3 as a Theranostic Agent for Hepatocellular Carcinoma

Glypican-3 (GPC3) is a membrane-associated glycoprotein that is significantly upregulated in hepatocellular carcinomas (HCC) with minimal to no expression in normal tissues. The differential expression of GPC3 between tumor and normal tissues provides an opportunity for targeted radiopharmaceutical therapy to treat HCC, a leading cause of cancer-related deaths worldwide. Methods: DOTA-RYZ-GPC3 (RAYZ-8009) comprises a novel macrocyclic peptide binder to GPC3, a linker, and a chelator that can be complexed with different radioisotopes. The binding affinity was determined by surface plasma resonance and radioligand binding assays. Target-mediated cellular internalization was radiometrically measured at multiple time points. In vivo biodistribution, monotherapy, and combination treatments with 177Lu or 225Ac were performed on HCC xenografts. Results: RAYZ-8009 showed high binding affinity to GPC3 protein of human, mouse, canine, and cynomolgus monkey origins and no binding to other glypican family members. Potent cellular binding was confirmed in GPC3-positive HepG2 cells and was not affected by isotope switching. RAYZ-8009 achieved efficient internalization on binding to HepG2 cells. Biodistribution study of 177Lu-RAYZ-8009 showed sustained tumor uptake and fast renal clearance, with minimal or no uptake in other normal tissues. Tumor-specific uptake was also demonstrated in orthotopic HCC tumors, with no uptake in surrounding liver tissue. Therapeutically, significant and durable tumor regression and survival benefit were achieved with 177Lu- and 225Ac-labeled RAYZ-8009, as single agents and in combination with lenvatinib, in GPC3-positive HCC xenografts. Conclusion: Preclinical in vitro and in vivo data demonstrate the potential of RAYZ-8009 as a theranostic agent for the treatment of patients with GPC3-positive HCC.

RYZ101 (Ac-225 DOTATATE) Opportunity beyond Gastroenteropancreatic Neuroendocrine Tumors: Preclinical Efficacy in Small-Cell Lung Cancer

Overexpression of somatostatin receptors (SSTR), particularly SSTR2, is found in gastroenteropancreatic neuroendocrine tumors (GEP-NET), and subsets of other solid tumors such as small-cell lung cancer (SCLC). SCLC accounts for approximately 13% to 15% of lung cancer and lacks effective therapeutic options. IHC analysis indicates that up to 50% of SCLC tumors are SSTR2-positive, with a substantial subset showing high and homogenous expression. Peptide receptor radionuclide therapy with radiolabeled somatostatin analogue, Lu-177 DOTATATE, has been approved for GEP-NETs. Different strategies aimed at improving outcomes, such as the use of alpha-emitting radioisotopes, are currently being investigated. RYZ101 (Ac-225 DOTATATE) is comprised of the alpha-emitting radioisotope actinium-225, chemical chelator DOTA, and octreotate (TATE), a somatostatin analogue. In the cell-based competitive radioligand binding assay, RAYZ-10001-La (lanthanum surrogate for RYZ101) showed high binding affinity (Ki = 0.057 nmol/L) to human SSTR2 and >600-fold selectivity against other SSTR subtypes. RAYZ-10001-La exhibited efficient internalization to SSTR2-positive cells. In multiple SSTR2-expressing SCLC xenograft models, single-dose intravenous RYZ101 3 μCi (0.111 MBq) or 4 μCi (0.148 MBq) significantly inhibited tumor growth, with deeper responses, including sustained regression, observed in the models with higher SSTR2 levels. The antitumor effect was further enhanced when RYZ101 was combined with carboplatin and etoposide at clinically relevant doses. In summary, RYZ101 is a highly potent, alpha-emitting radiopharmaceutical agent, and preclinical data demonstrate the potential of RYZ101 for the treatment of patients with SSTR-positive cancers.

Palliative care for persons with late-stage Alzheimer's and related dementias and their caregivers: protocol for a randomized clinical trial

BACKGROUND

Limited access to specialized palliative care exposes persons with late-stage Alzheimer's disease and related dementias (ADRD) to burdensome treatment and unnecessary hospitalization and their caregivers to avoidable strain and financial burden. Addressing this unmet need, the purpose of this study was to conduct a randomized clinical trial (RCT) of the ADRD-Palliative Care (ADRD-PC) program.

METHODS

The study will use a multisite, RCT design and will be set in five geographically diverse US hospitals. Lead investigators and outcome assessors will be masked. The study will use 1:1 randomization of patient-caregiver dyads, and sites will enroll N = 424 dyads of hospitalized patients with late-stage ADRD with their family caregivers. Intervention dyads will receive the ADRD-PC program of (1) dementia-specific palliative care, (2) standardized caregiver education, and (3) transitional care. Control dyads will receive publicly available educational material on dementia caregiving. Outcomes will be measured at 30 days (interim) and 60 days post-discharge. The primary outcome will be 60-day hospital transfers, defined as visits to an emergency department or hospitalization ascertained from health record reviews and caregiver interviews (aim 1). Secondary patient-centered outcomes, ascertained from 30- and 60-day health record reviews and caregiver telephone interviews, will be symptom treatment, symptom control, use of community palliative care or hospice, and new nursing home transitions (aim 2). Secondary caregiver-centered outcomes will be communication about prognosis and goals of care, shared decision-making about hospitalization and other treatments, and caregiver distress (aim 3). Analyses will use intention-to-treat, and pre-specified exploratory analyses will examine the effects of sex as a biologic variable and the GDS stage.

DISCUSSION

The study results will determine the efficacy of an intervention that addresses the extraordinary public health impact of late-stage ADRD and suffering due to symptom distress, burdensome treatments, and caregiver strain. While many caregivers prioritize comfort in late-stage ADRD, shared decision-making is rare. Hospitalization creates an opportunity for dementia-specific palliative care, and the study findings will inform care redesign to advance comprehensive dementia-specific palliative care plus transitional care.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04948866. Registered on July 2, 2021.

Comparing Patient-Reported Outcomes Among Anti-TNF-Experienced Patients with Crohn's Disease Initiating Vedolizumab Versus Ustekinumab

BACKGROUND

Primary and secondary non-response to anti-tumor necrosis factor (TNF) therapy is common in patients with Crohn's disease (CD), yet limited research has compared the effectiveness of subsequent biological therapy.

OBJECTIVE

We sought to compare the effectiveness of vedolizumab and ustekinumab in anti-TNF-experienced patients with CD, focusing on patient-prioritized patient-reported outcomes (PROs).

METHODS

We conducted a prospective, internet-based cohort study nested within IBD Partners. We identified anti-TNF-experienced patients initiating with CD vedolizumab or ustekinumab and analyzed PROs reported approximately 6 months later (minimum 4 months, maximum 10 months). Co-primary outcomes were Patient-Reported Outcome Measurement Information System (PROMIS) domains of Fatigue and Pain Interference. Secondary outcomes included patient-reported short Crohn's disease activity index (sCDAI), treatment persistence, and corticosteroid use. Inverse probability of treatment weighting (IPTW) was used to control for a number of potential confounders and incorporated into linear and logistic regression models for continuous and categorical outcomes, respectively.

RESULTS

Overall, 141 vedolizumab and 219 ustekinumab initiators were included in our analysis. After adjustment, we found no differences between treatment groups in our primary outcomes of Pain Interference or Fatigue or the secondary outcome of sCDAI. However, vedolizumab was associated with lower treatment persistence (OR 0.4, 95% CI 0.2-0.6) and higher corticosteroid use at follow-up assessment (OR 1.7, 95% CI 1.1-2.6).

DISCUSSION

Among anti-TNF experienced patients with CD, Pain Interference or Fatigue was not significantly different 4-10 months after starting ustekinumab or vedolizumab. However, reduced steroid use and increased persistence suggest superiority of ustekinumab for non-PRO outcomes.

Mitral valve dysfunction among sudden death victims

Funding Acknowledgements

Type of funding sources: None.

Introduction

Mitral dysfunction is a commonly found valvular abnormality in the US. The association between mitral dysfunction with sudden death is both complex and controversial.

Purpose

To assess mitral dysfunction as a potential risk factor for sudden death using medical and autopsy records in a population-based registry of sudden deaths.

Methods

From 2013-2015, out-of-hospital deaths aged 18-64 reported by Emergency Medical Services in Wake County, North Carolina were screened to adjudicate 399 sudden death victims. Medical records were available in 270 victims, echocardiograms in 53, and autopsies in 64. Echocardiogram reports of none/trace/trivial mitral insufficiency were compared to patients with mild, moderate, or severe insufficiency. Autopsy reports for thickened mitral leaflets, calcification, and redundancy were reviewed. Additionally, available echocardiograms from a control group of 1101 patients were reviewed for mitral insufficiency. Demographics and clinical comorbidities were assessed from medical and death records. Mean, t-tests, and a bivariate logistic regression were estimated, as appropriate.

Results

Of the 53 victims with echocardiograms, mean age was 53 years, 36 (65.5%) were male, and 21 (39.6%) were African-American. Victims with available echocardiograms were more likely to have congestive heart failure (41.8%), coronary artery disease (50.9%), and diabetes (47.3%) compared to victims without echocardiograms. None/trivial/trace insufficiency was present in 27 victims (50.9%), mild insufficiency in 18 (34.0%), and moderate-severe insufficiency in 8 (15.1%). There was no association between severity of mitral insufficiency with demographic covariates or comorbid conditions. The presence of structural mitral valve abnormalities, including thickened leaflets, calcification, and redundancy of the mitral valve, were present in only 8 (12.5%) of 64 victims with autopsies. In a control group of 1101 date-matched patients from the same county, 57 (4.8%) patients had an echocardiogram available. 14 (24.6%) of these patients had mild-moderate mitral insufficiency.

Conclusion

Mitral insufficiency and structural abnormalities of the mitral valve are often identified in echocardiograms or autopsies of sudden death victims. Living controls had approximately half the prevalence of mitral insufficiency, suggesting that mitral dysfunction and its associated comorbidities are associated with sudden death.

[Relationship between c-kit mRNA expression and prognosis in patients with rectal carcinoma]

Objective: To investigate the correlation between c-kit mRNA expression and prognosis in patients with rectal carcinoma. Methods: The expression of c-kit mRNA in rectal carcinoma tissues(n=66) was detected by multiplex branched-DNA liquid chip method. According to the expression level, the patients were classified into the c-kit mRNA high expression group and the low group. We analyzed the relationship between the c-kit mRNA expression and the clinicopathological characteristics of patients, as well as the factors affecting patients'prognosis. Results: Of the 66 rectal carcinoma patients, 18(27.3%)cases were c-kit mRNA high expression. No significant correlation was found between the c-kit mRNA expression and gender, age, preoperative carcinoembryonic antigen, preoperative hemoglobin, distance to verge, lymph node metastasis, tumor thrombus, T stage, TNM stage and tumor differentiation (P>0.05). In follow-up, 34 patients died, 32 patients and 36 patients were recurrence or metastasis. The 1-, 3-, 5-year overall survival(OS) of c-kit mRNA high expression group were 100.0%, 77.8%, 77.8%, respectively, while those of the low one were 93.8%, 56.3%, 45.8%, respectively. The difference was statistically significant(P=0.025). Lymph node metastasis, T stage and TNM stage were also significant associated with OS(P<0.05). The 1-, 3-, 5-year disease free rate (DFS)of the c-kit mRNA high expression group were 100.0%, 77.8% and 77.8%, respectively, while those of the low one were 77.1%、43.8% and 41.7%, respectively, and the difference between the two groups was significant (P=0.044). As a reslut, c-kit mRNA expression (P=0.038) and TNM stage (P=0.039) were the independent prognostic factors affecting the OS in rectal cancer patients. Conclusions: Low expression of c-kit was associated with poor prognosis of rectal carcinoma. And the mechanism underlying this phenomenon deserves further exploration.

Procoagulant microparticles promote coagulation in a factor XI-dependent manner in human endotoxemia

Essentials The procoagulant effects of microparticles (MPs) on coagulation in endotoxemia are not known. MPs from endotoxemia volunteers were evaluated for procoagulant activity in a plasma milieu. MPs from endotoxemia volunteers shortened clotting times and enhanced thrombin generation. MP procoagulant effects were mediated in a factor XI-dependent manner.

SUMMARY

Background Human endotoxemia is characterized by acute inflammation and activation of coagulation, as well as increased numbers of circulating microparticles (MPs). Whether these MPs directly promote coagulation and through which pathway their actions are mediated, however, has not been fully explored. Objectives In this study, we aimed to further characterize endotoxin-induced MPs and their procoagulant properties using several approaches. Methods Enumeration and characterization of MPs were performed using a new-generation flow cytometer. Relative contributions of the extrinsic and intrinsic pathways in MP-mediated procoagulant activity were assessed using plasmas deficient in factor (F) VII or FXI or with blocking antibodies to tissue factor (TF) or FXIa. Results Total MPs and platelet MPs were significantly elevated in plasma at 6 h after infusion of endotoxin in healthy human subjects. MPs isolated from plasma following endotoxin infusion also demonstrated increased TF activity in a reconstituted buffer system. When added to recalcified platelet-poor plasma, these MPs also promoted coagulation, as judged by a decreased clotting time with shortening of the lag time and time to peak thrombin using calibrated automated thrombography (CAT). However, the use of FVII-deficient plasma or blocking antibody to TF did not inhibit these procoagulant effects. In contrast, plasma clotting time was prolonged in FXI-deficient plasma and a blocking antibody to FXIa inhibited all MP-mediated parameters in the CAT assay. Conclusions The initiation of coagulation by cellular TF in endotoxemia is in contrast to (and presumably complemented by) the intrinsic pathway-mediated procoagulant effects of circulating MPs.

Adolescents with Type 1 diabetes mellitus experience psychosensorial symptoms during hypoglycaemia

AIM

To describe mood and psychosensorial symptoms of hypoglycaemia in adolescents with Type 1 diabetes mellitus in two countries with different cultures, Turkey and the USA.

METHODS

We developed a 68-item questionnaire assessing physical, behavioural, mood and psychosensorial symptom frequency and ratings ['good', 'bad', or 'both' (sometimes good, sometimes bad)]. Adolescents with Type 1 diabetes were recruited from paediatric diabetes clinics at the University of North Carolina at Chapel Hill in the USA and Kocaeli University in Turkey. The percentages of participants at each clinic who endorsed individual symptoms, symptom categories and symptom ratings were calculated and compared.

RESULTS

Cronbach's α values were > 0.7 for each real symptom category. No symptom items were excluded from the questionnaire analysis based on item-total correlation results which were all > 0.2. Data were collected from 132 participants (69 from University of North Carolina, 63 from Kocaeli University, 54% male). The mean (SD) age of the participants was 14.9 (1.9) years, HbA1c level was 8.7 (1.8) % and duration of Type 1 diabetes was 5.8 (3.7) years. On average, each physical symptom was experienced by 65.2% of participants, each behavioural symptom by 46.5%, each mood symptom by 42.8%, and each psychosensorial symptom by 48.9%. On average, each physical, behavioral, mood and psychosensorial symptom was rated as 'good' or 'both' by 23.0, 29.1, 36.9 and 37.2% of participants, respectively. There were no symptom differences between the groups in each country.

CONCLUSIONS

In addition to the classic physical symptoms experienced during hypoglycaemia, adolescents with Type 1 diabetes report psychosensorial, mood and behavioral symptoms, and some describe them as positive experiences. Symptom experiences were similar in these two countries with different cultures.

Interferons: Success in anti-viral immunotherapy

The interferons (IFNs) are glycoproteins with strong antiviral activities that represent one of the first lines of host defense against invading pathogens. These proteins are classified into three groups, Type I, II and III IFNs, based on the structure of their receptors on the cell surface. Due to their ability to modulate immune responses, they have become attractive therapeutic options to control chronic virus infections. In combination with other drugs, Type I IFNs are considered as "standard of care" in suppressing Hepatitis C (HCV) and Hepatitis B (HBV) infections, while Type III IFN has generated encouraging results as a treatment for HCV infection in phase III clinical trials. However, though effective, using IFNs as a treatment is not without the need for caution. IFNs are such powerful cytokines that affect a wide array of cell types; as a result, patients usually experience unpleasant symptoms, with a percentage of patients suffering system wide effects. Thus, constant monitoring is required for patients treated with IFN in order to reach the treatment goals of suppressing virus infection and maintaining quality of life.

The pivotal role of IKKα in the development of spontaneous lung squamous cell carcinomas

Here, we report that kinase-dead IKKα knockin mice develop spontaneous lung squamous cell carcinomas (SCCs) associated with IKKα downregulation and marked pulmonary inflammation. IKKα reduction upregulated the expression of p63, Trim29, and keratin 5 (K5), which serve as diagnostic markers for human lung SCCs. IKKα(low)K5(+)p63(hi) cell expansion and SCC formation were accompanied by inflammation-associated deregulation of oncogenes, tumor suppressors, and stem cell regulators. Reintroducing transgenic K5.IKKα, depleting macrophages, and reconstituting irradiated mutant animals with wild-type bone marrow (BM) prevented SCC development, suggesting that BM-derived IKKα mutant macrophages promote the transition of IKKα(low)K5(+)p63(hi) cells to tumor cells. This mouse model resembles human lung SCCs, sheds light on the mechanisms underlying lung malignancy development, and identifies targets for therapy of lung SCCs.

MicroRNA-29 Stabilizes IFN-γ mRNA by inhibiting GW182 (174.5)

Tight regulation of interferon-gamma (IFN-γ) expression is critical for an optimal immune response. We have extensively studied the mechanisms responsible for the post-transcriptional regulation of IFN-γ expression. AU-rich element (ARE)-mediated decay (AMD) via the tristetraprolin (TTP) complex is responsible for robust degradation of the IFN-γ mRNA. We found that microRNA-29 (miR-29) targets the IFN-γ 3’UTR and, unlike the conventional inhibitory miRNAs, stabilizes the mRNA. Resolution of the secondary structure showed that the ARE and miR-29 binding site are in close proximity and a series of experiments manipulating the RNA structure revealed that this proximity enables miR-29 to antagonize TTP degradation. Interestingly, miR-29 is unable to degrade the mRNA even in the absence of TTP. Recently we have found that GW182, a major degradation protein in the miRISC, is unable to be recruited to the mRNA as a result of the location of the miR-29 binding site in the secondary structure. The ability of miR-29 to stabilize the IFN-γ mRNA demonstrates a novel molecular mechanism of miRNA regulation.

IFN-gamma is the primary cause of aplastic anemia not autoreactive T cells (111.2)

Aplastic anemia (AA) is characterized by hypocellular marrow and peripheral pancytopenia. Although cases of AA caused by environmental factors have been reported, the etiology of AA is largely unknown. Since IFN-γ and T-bet can be detected in AA patients' T cells, it was believed that autoreactive T lymphocytes played a major role in destroying the hematopoietic stem cells (HSCs) in bone marrow (BM). Thus, AA has been treated as an autoimmune disease. We have observed AA-like symptoms in our IFN-γ AU-rich element (ARE) knock-out (KO) mice. These mice have a targeted deletion in the 3'untranslated region of the IFN-γ mRNA. The deletion increases the half-life of IFN-γ mRNA. Thus, these mice constitutively express low level of IFN-γ under normal condition. In this study, we used IFN-γ ARE KO mice as an animal model to understand the etiology of AA. These mice exhibited signs of immunodeficiency when their immune organs were examined. Also, T cells from these mice failed to produce cytokines when stimulated with anti-CD3 and anti-CD28 antibodies. Upon examining the cell population in BM, we did not detect any infiltration of T cells. In addition, we observed an increase in long term HSCs (LT-HSCs) and a decrease in short term HSCs (ST-HSC). We also observed the same phenomena in WT recipients of IFN-γ ARE KO BM. The results of this study suggest AA occurs when IFN-γ inhibits the generation of ST-HSCs from LT-HSCs, as opposed to infiltration of autoreactive T cells.

Abstract 2560: IKKα inactivation predisposes to spontaneous lung squamous cell carcinomas

Lung cancer is the leading cause of cancer deaths worldwide. To advance the understanding of this disease, various genetically engineered and chemical induced mouse models have been established. However, most animal models resemble human lung adenocarcinoma, and spontaneous lung squamous cell carcinomas (SCCs) mouse models are very rare. Here, we generated Ikkα-KA/KA knock-in mice (KA/KA) in which an ATP binding site of IKKα, Lys 44 was replaced by alanine. The knock-in mice develop severe skin lesions and begin to die after 6 months. We found lung SCCs in some of the mice. To study lung SCC development, we decided to stabilize the skin condition by reintroducing transgenic IKKα by crossing KA/KA with Lori.IKKα transgenic mice to generate KA/KA/Lori.IKKα (KA/KAL) mice. Almost all the KA/KAL (100%) mice at 4 to 6 months of age developed spontaneous lethal lung SCCs. The endogenous IKKα protein level generally markedly declined in an age dependent manner in these IKKα mutant mice. Progenitor cell related markers Sox2, OCT3/4 and Nanog were only increased in the lung SCC tissue but not in the tumor adjacent tissues, implying the involvement of cancer stem cells in lung SCC. Furthermore, we detected substantial increases in Ras and CyclinD1 levels and EGFR, ERK and p38 activities in lung SCCs. On the other hand, we detected reduction in tumor suppressor gene Rb and IαBβ accompanying with reduced IKKα levels in KA/KAL lungs as well as in lung SCCs. Importantly, we observed a similar alteration pattern in mouse and human lung SCCs. Finally, reintroducing IKKα into lung epithelial cells prevented lung SCC development in mice. Collectively, our study supports the tumor suppressing role of IKKα in lung tumorigenesis. This novel lung SCC mouse model may facilitate investigations in pathogenesis, diagnosis, and treatment of human lung SCC disease.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2560. doi:1538-7445.AM2012-2560

Chronic IFN-gamma expression alters the migration pattern of peripheral T cells (160.7)

We report here on preliminary data from an IFN-gamma(IFN-γ)ARE-deleted Balb/c mouse model developed in our laboratory.This mouse has a 162 nt deletion in the 3’untranslated region of the IFN-γ mRNA to eliminate an AU-rich sequence. The deletion has a positive impact on IFN-γ mRNA accumulation by dramatically increasing its half-life. In the absence of stimulatory factors,these mice express low level of IFN-γ constitutively. IFN-γ ARE-deletion results in a severe phenotype on Balb/c mice. The knockout (KO) and heterozygous (Het) mice are smaller in size than the littermate controls, have a rough coat and a low survival rate after weaning. Additionally, these mice have an enlarged thymus with an increased percentage of mature naïve T cells. The mature thymocytes from Het animals are able to leave the thymus and enter peripheral lymphoid tissues. However, the results from chimera experiments indicate that IFN-γ may impact the thymic environment, thus resulting in abnormal T cell development. In addition, we found the migration pattern of peripheral T cells from Het mice differs from that observed with cells from control animals, further suggesting an abnormality in the Het T cell physiology. Current experiments focus on analyzing changes in the thymic environment and T cell development in newborn mice. In addition, we are analyzing chemokine receptor expression to determine if changes in these receptors may be a mitigating factor in the T cell migration patterns.

Synthesis of Fibrils in Vitro by a Solubilized Cellulose Synthase from Acetobacter xylinum

A digitonin-solubilized cellulose synthase was prepared from Acetobacter xylinum. When this enzyme was incubated under conditions known to lead to active synthesis of 1,4-beta-D-glucan polymer (cellulose), electron microscopy revealed that clusters of fibrils were assembled within minutes. Individual fibrils are 17 +/- 2 angstroms in diameter. Evidence that the fibrils were freshly synthesized and cellulosic in nature was their incorporation of the tritium from UDP-[(3)H]glucose (UDP, uridine 5'-diphosphate), their binding of gold-labeled cellobiohydrolase, and an electron diffraction pattern with 004, 200, and 012 reflections (characteristic of cellulose synthesized in vivo) but missing 110 and 110 reflections. The small size of the fibrils is atypical of native A. xylinum cellulose microfibrils. The fibrils synthesized in vitro resemble, in morphology and size, the fibrillar cellulose produced when A. xylinum is cultured in the presence of agents that interfere with the normal process of crystallization of the microfibrils. The solubilized enzyme unit may therefore be producing a basic fibrillar structure that, in vivo, interacts laterally with other fibrils to produce native cellulose microfibrils.

Pseudotyped single-cycle simian immunodeficiency viruses expressing gamma interferon augment T-cell priming responses in vitro

To increase the safety and efficacy of human immunodeficiency virus vaccines, several groups have conducted studies using the macaque model with single-cycle replicating simian immunodeficiency viruses (SIVs). However, these constructs had poor or diminished efficacy compared to live attenuated vaccines. We previously showed that immunization of macaques with live attenuated SIV with a deletion in the nef gene and expressing gamma interferon (IFN-gamma) results in significantly enhanced safety and efficacy. To further enhance safety, we constructed and characterized single-cycle SIVs, pseudotyped with the glycoprotein of vesicular stomatitis virus, expressing different levels of macaque IFN-gamma. Expression of IFN-gamma did not alter the infectivity or antigenicity of pseudotyped SIV. The transduction of dendritic cells (DCs) by IFN-gamma-expressing particles resulted in the up-regulation of costimulatory and major histocompatibility complex molecules. Furthermore, T cells primed with DCs transduced by SIV particles expressing high levels of IFN-gamma and then stimulated with SIV induced significantly higher numbers of spot-forming cells in an enzyme-linked immunospot assay than did T cells primed with DCs transduced with SIV particles lacking the cytokine. In conclusion, we demonstrated that the transduction of DCs in vitro with pseudotyped single-cycle SIVs expressing IFN-gamma increased DC activation and augmented T-cell priming activity.

Diffusion tensor imaging in the assessment of normal-appearing brain tissue damage in relapsing neuromyelitis optica

BACKGROUND AND PURPOSE

Normal-appearing brain tissue (NABT) damage was established in multiple sclerosis by histology, MR spectroscopy, magnetization transfer imaging and diffusion tensor imaging (DTI). However, whether this phenomenon can be detected in relapsing neuromyelitis optica (RNMO) remains unclear. The aim of this study was to use DTI to investigate the presence of NABT damage in RNMO patients and its possible mechanism.

METHODS

Conventional MR imaging and DTI scans were performed in 16 patients with RNMO without visible lesions on brain MR imaging and in 16 sex- and age-matched healthy control subjects. Histogram analysis of mean diffusivity (MD) and fractional anisotropy (FA) was performed in the entire brain tissue (BT), white matter (WM), and gray matter (GM). Region of interest (ROI) analysis of MD and FA was also performed in WM regions connected with the spinal white matter tracts or optic nerve (including medulla oblongata, cerebral peduncle, internal capsule, and optic radiation), in corpus callosum without direct connection with them, and in some GM regions.

RESULTS

From histogram analysis, we found the RNMO group had a higher average MD of the BT, WM, and GM, a lower average MD peak height and a higher average MD peak location of the GM, and a higher average FA peak height of the WM than did the control group. From ROI analysis, compared with control subjects, RNMO patients had a higher average MD and a lower average FA in ROIs of WM connected with the spinal white matter tracts or optic nerve and a normal average MD and FA in corpus callosum without direct connection with them. In addition, a high average MD was found in parietal GM in these patients.

CONCLUSIONS

Our findings confirm the presence of abnormal diffusion in brain tissue in patients with RNMO and suggest that secondary degeneration caused by lesions in the spinal cord and optic nerve might be an important mechanism for this abnormality.

Effect of thiopental, propofol, and etomidate on vincristine toxicity in PC12 cells

Neurotoxicity is the dose-limiting side-effect of vincristine in cancer therapy. Using the nerve growth factor (NGF)-dependent neurite outgrowth and cell proliferation of the PC12 pheochromocytoma cell line as an in vitro assay, the protective effect of different intravenous anesthetics was assessed. Vincristine (1 nmol/L) significantly decreased the percentage of neurite-forming cells from 68% +/- 9% to 27% +/- 7% within a 3-day incubation period. The longer neurites (> 2 x cell body) in particular proved to be extremely sensitive to vincristine (from 17% +/- 4% to 0% of total neurite-expressing cells). Flow cytometry results revealed an S-phase percentage of 15.85% +/- 3.25% after NGF induction, with vincristine reducing this percentage to 0.68% +/- 0.38%. Reversal of the inhibitory effect of vincristine was noted in the cells treated with thiopental or propofol but not etomidate. Bicuculline partially antagonized the protective effect of thiopental and propofol in both studies. We conclude that thiopental and propofol, but not etomidate, have a protective effect in vincristine-induced neurotoxicity. The protective effect produced by thiopental and propofol is probably secondary to activation of GABAA receptors.

Usefulness of the suspended microbubble sign in differentiating empyemic and nonempyemic hydropneumothorax

OBJECTIVE

The suspended microbubble sign is defined as the image seen on ultrasonography consisting of a pleural effusion strewn with numerous hyperechoic pinpoints and more or less linear shadows that move synchronously with respiration. In this study, we intended to evaluate the clinical usefulness of the suspended microbubble sign in differentiating empyemic and nonempyemic hydropneumothorax.

METHODS

This series consisted of 8 patients with empyemic hydropneumothorax and 23 patients with nonempyemic hydropneumothorax. The finding of the presence of the suspended microbubble signs on ultrasonography was recorded. To further elucidate the generation of the suspended microbubble sign, the interaction between air and pleural fluid of different types was investigated in vitro.

RESULTS

The suspended microbubble sign was shown on ultrasonography in all 8 patients with empyemic hydropneumothorax but was absent in the 23 patients with nonempyemic hydropneumothorax. These findings were supported by the observation that the pus seemed to mix with and trap the air more easily than did the nonpurulent pleural fluid, as shown in vitro. In this selected population, the sensitivity and specificity of the suspended microbubble sign in aiding a diagnosis of empyemic hydropneumothorax were both 100%.

CONCLUSION

The suspended microbubble sign shown on ultrasonography might be of considerable value in differentiating empyemic and nonempyemic hydropneumothorax.

Plate atelectasis: an implication of foreign body aspiration into the lower airways in two adults

Pneumonic patches and atelectatic or bronchiectatic changes in the tributary lung distal to the bronchial foreign body are common radiographic abnormal findings in adults with foreign body aspiration into the lower airways. Nevertheless, plate (plate-like or discoid) atelectasis, a form of peripheral atelectasis, has not been reported to associate with this condition. In this report, we describe two men with the foreign body impacted in the right intermediate bronchus. In both cases, plate atelectasis was found in the base of the right lung and disappeared after successful removal of the foreign body via fiberoptic bronchoscopy. These two cases illustrate that plate atelectasis may be an implication of foreign body aspiration into the lower airways.

A nonparametric estimator of species overlap

For two communities, species overlap has been defined by Smith, Solow, and Preston (1996, Biometrics 52, 1472-1477) as the probability that a randomly selected species is present in both communities given that it is present in at least one community. Species overlap can thus be used to describe the similarity of two communities. In contrast with the parametric estimator of Smith et al., we propose a nonparametric maximum likelihood estimator (NPMLE). We prove that the NPMLE is consistent and asymptotically normally distributed and show that computation of the NPMLE and its standard error is straightforward. We also compare the NPMLE and the estimator of Smith et al. for a variety of situations.

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

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

Diagnosis of pulmonary alveolar proteinosis: usefulness of papanicolaou-stained smears of bronchoalveolar lavage fluid

BACKGROUND

The globules (stained green, orange, or orange in the center coated with a green rim) seen in Papanicolaou-stained smears of bronchoalveolar lavage fluid are suggested to be characteristic of pulmonary alveolar proteinosis (PAP).

OBJECTIVE

To evaluate the usefulness of Papanicolaou-stained smears of bronchoalveolar lavage fluid in aiding a diagnosis of PAP.

METHODS

Papanicolaou-stained smears of bronchoalveolar lavage fluid obtained from 7 patients (5 idiopathic, 2 secondary) with PAP were evaluated. To serve as controls, the smears of 11 normal subjects and 128 patients with other pulmonary disorders were also examined. The findings on the presence and number of globules were recorded. To differentiate PAP from other pulmonary disorders, the highest globule value obtained from the control group was chosen as the cutoff point.

RESULTS

The characteristic globules were not found in normal subjects and only found in 6 of 128 patients with other pulmonary disorders. Their clinical diagnoses were Sjögren syndrome in 2 cases; polymyositis, idiopathic pulmonary fibrosis, asbestosis, and hypersensitivity pneumonitis in 1 case each. The numbers of globules in these 6 patients were 1, 3, 17, 7, 3, and 2. In contrast, more than 100 globules were found in all patients with PAP. The number of globules was highly sensitive and specific in aiding a diagnosis of PAP when the cutoff value was set at 18.

CONCLUSION

The globules seen in Papanicolaou-stained smears of bronchoalveolar lavage fluid may be valuable in aiding a diagnosis of PAP, especially when the number of globules is more than 18.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Comparison of appendectomy medical expense and clinical outcome between fee for service and prospective payment system

Since the introduction of national health insurance on March 1st 1995 in Taiwan, another 9 items (including appendectomy) were introduced into the Taiwan/prospective payment system (T/PPS). The modified T/PPS was based on those complicated appendectomy cases with secondary diagnosis or second operation where a total fee over 37,500 New Taiwan (NT) dollars was paid by National Health Insurance Bureau (NHIB) according to the real cost. The T/PPS was implemented in October 1997 due to the continuously increasing financial burden of medical expenses on the NHIB. The purpose of this study is (1) to compare the length of stay (LOS) and total medical expense of appendectomy of fee for service (FFS) and T/PPS and (2) to compare the clinical outcome of wound healing after discharge of the two systems by telephone interview. Our study investigated 100 consecutive appendectomy cases under FFS payment system and 99 consecutive appendectomy cases under T/PPS. We retrospectively analyzed LOS, operation time, and hospital cost of different items through chart review and computer data. Our results revealed that the LOS and operation time of T/PPS were significantly shorter than those of FFS (both p < 0.01). The total hospital cost, fee for room service, treatment, pharmacy, examination and anesthesia in T/PPS were also significantly less than those in FFS (all p < 0.01, except for anesthesia p < 0.05). There existed positive correlation between total hospital cost and LOS, operation time, fee for room service, treatment, pharmacy, examination and anesthesia both for T/PPS and FFS. To evaluate the clinical outcome of appendectomy between T/PPS and FFS, we interviewed 73 T/PPS cases and 73 FFS cases by telephone and chart review. Our results revealed that there were no significant differences in frequencies of having painful incision, clear incision wound on the day of discharge, and removal of stitches at hospital (p all > 0.05). We concluded that compared to FFS, T/PPS can decrease LOS and total hospital cost of appendectomy, and T/PPS's clinical outcome of appendectomy in T/PPS showed no significant difference from that in FFS.

Successful lysis of right and left heart thrombus by tissue plasminogen activator

Tissue plasminogen activator (t-PA) was administered to three patients with newly developed intracardiac thrombi. Cases 1 and 2 developed right heart thrombi after radiofrequency ablation for atrioventricular nodal reentrant tachycardia and case 3 had tachycardia-related cardiomyopathy and a left ventricular thrombus. In all three patients, the intracardiac thrombi were successfully eliminated following t-PA therapy without major bleeding complications. These observations suggest that t-PA is effective in lysing new thrombus complicating radiofrequency ablation or heart failure and may be the therapy of choice in these conditions. Cathet. Cardiovasc. Intervent. 49:91-96, 2000.

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

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

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

OBJECTIVES

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The use of multiplane transesophageal echocardiography to evaluate residual patent ductus arteriosus during video-assisted thoracoscopy in adults

BACKGROUND

Video-assisted thoracoscopic surgery (VATS) has emerged as an innovative and popular procedure for interruption of patent ductus arteriosus (PDA), while intraoperative transesophageal echocardiography (TEE) has proven to be an effective monitor in the evaluation of residual patency. Previous reports on the adequacy of surgical interruption of PDA under VATS and TEE are available for pediatric patients, but only limited information is available for adults with PDA. MATEIALS AND METHODS: Between August 1995 and October 1997, we monitored 35 adult patients undergoing PDA interruption via VATS with Hewlett-Packard color Doppler multiplane TEE throughout the procedure. The average PDA diameter was 10.2 +/- 1.8 mm. All the PDA were completely ligated.

RESULTS

Thirty-two patients showed no ductal flow after double ligation. In the other three patients, residual flow was detected intraoperatively after double ligation, but it was quickly abolished by the third ligation. One patient showed faint ductal flow by transthoracic echocardiography at postoperative follow-up, but no reintervention was needed.

CONCLUSIONS

Our study showed that, with the refinement of adult PDA interruption via VATS, intraoperative multiplane TEE provides higher resolution for direct evaluation of the entire course of PDA ligation without interrupting the surgical procedure and minimizes the incidence of complications.

Aberrant infrarenal inferior vena cava as a hindrance to percutaneous transvenous mitral valvuloplasty in a patient with mitral stenosis: case report

Cardiac catheterization and percutaneous transvenous mitral commissurotomy using the Inoue technique were attempted in a 44-year-old woman with mitral stenosis. The pulmonary arterial wedge pressure was 25 mmHg, mean transmitral diastolic pressure gradient 20.3 mmHg, cardiac index 1.80 L/min/m2, and mitral valve area 0.70 cm2. After the diagnostic catheterization, the guide wire for the transseptal procedure was checked in the middle of the inferior vena cava (IVC). A 7-French end-holed Bermann catheter was then used to detect the course of the IVC. It was found that the IVC coursed along the left border of the 4th and 5th lumbar vertebrae, to the left of the abdominal aorta. At the upper border of the third lumbar vertebra, the IVC returned to the right side of the vertebra. In consideration of the inability to pass the Brockenbrough needle through the detoured infrarenal IVC and the risk of rupturing the vessel, the transseptal procedure and attempted percutaneous transvenous mitral commissurotomy were aborted. Therefore, the patient underwent open mitral commissurotomy instead.

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

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

Comparison of antihypertensive efficacy and tolerability of losartan and extended-release felodipine in patients with mild to moderate hypertension

Appropriate control of blood pressure has been shown to reduce morbidity and mortality in patients with hypertension. Losartan potassium, a selective antagonist of the angiotensin II type 1 (AT1) receptor, has been shown to lower blood pressure in patients with hypertension. The purpose of this study was to compare the efficacy and tolerability of losartan and extended-release (ER) felodipine in Taiwanese patients with mild to moderate hypertension. Patients with mild to moderate hypertension (sitting diastolic blood pressure, 95-115 mm Hg) were enrolled in this prospective, randomized, parallel study. Sitting blood pressure, heart rate, adverse reactions, and serum biochemistry values were assessed during 2 weeks of placebo and 12 weeks of active treatment. Each patient received 50 mg of losartan or 5 mg of felodipine ER once daily, and the dosage was adjusted to double the initial level at week 6 if necessary. Of the 44 patients randomly allocated to receive losartan (n = 23) or felodipine (n = 21) therapy, 37 completed the study; three patients in the losartan group and four in the felodipine group withdrew because of adverse experiences, or were lost to follow-up. The mean reductions in sitting diastolic blood pressure at 6 and 12 weeks were significant with both losartan (-8.6 and -11.38 mm Hg, respectively) and felodipine (-9.2 and -10.69 mm Hg, respectively), and did not differ significantly between the two groups. Both losartan and ER felodipine were well tolerated by patients. However, the ER felodipine group had a significantly higher rate of drug-related flushing than the losartan group (24% vs 0%, p = 0.022). The results indicate that once-daily administration of losartan is as effective and well tolerated as once-daily ER felodipine in blood pressure reduction.

Hemolytic anemia in native valve infective endocarditis: a case report and literature review

Hemolytic anemia is a rare manifestation of infective endocarditis. A 19-year-old man with a small ventricular septal defect developed right-sided infective endocarditis with huge vegetations involving the tricuspid valve, the ventricular septal defect, and the pulmonary valve. Intravascular hemolysis was suggested by the presence of numerous fragmented erythrocytes, giant platelets and polychromasia of the red blood cells. The direct Coombs test was positive, and there were spherocytes and splenomegaly, findings that suggested an immune-mediated mechanism also played a role in the hemolysis. The hematological picture persisted despite antibiotic therapy and recovered only after surgical removal of the vegetations, tricuspid and pulmonary valvectomy, and patch closure of the ventricular septal defect.

Comparison of clinical efficacy and adverse effects between extended-release felodipine and slow-release diltiazem in patients with isolated systolic hypertension

BACKGROUND

Isolated systolic hypertension (ISH) is a risk factor for cardiovascular disease. Extended-release felodipine (felodipine ER) has been shown to be effective in the treatment of ISH in Caucasians. However, its pharmacological properties are different from another calcium blocker, diltiazem. Also, the effectiveness, tolerability, and adverse reactions of these two antihypertensive agents for ISH have not been thoroughly assessed in Chinese.

METHODS

Sitting blood pressures (BP), heart rate, body weight, adverse reactions, and serum biochemistry were assessed in 70 patients with isolated systolic hypertension (34 treated with felodipine ER and 36 slow-release diltiazem [diltiazem SR] for 10 weeks). Each patient was given 5 mg of felodipine ER or 90 mg of diltiazem SR once daily and was doubled to twice daily if necessary.

RESULTS

Five patients on felodipine ER and four on diltiazem SR withdrew because of intolerable side effects. By ten weeks, 67.6% of the patients responded to a daily dose of 5-10 mg of felodipine ER and 58.3% to a daily dose of 90-180 mg of diltiazem SR. At the end of treatment, felodipine ER lowered the mean BP from 187/83 mmHg at baseline to 149/74 mmHg, whereas diltiazem SR decreased the BP from 185/84 mmHg to 158/78 mmHg (not significant between the two groups). The heart rate did not change significantly in either group. Overall, these two groups of patients had the same rate of adverse reactions (50.0% vs. 50.0%) with similar profiles of the adverse effects.

CONCLUSION

Equivalent doses of felodipine ER and diltiazem SR are effective first-line monotherapeutic agents for the treatment of ISH.

Variation of P-QRS relation during atrioventricular node reentry tachycardia

OBJECTIVES

The main objective of this study was to characterize the phenomenon of variation in the P-QRS relation during atrioventricular node reentry tachycardia.

BACKGROUND

Variation of P-QRS relation during tachycardia has been observed occasionally in atrioventricular node reentry tachycardia. However, the incidence, the characteristics and the mechanisms of this phenomenon have not been investigated previously.

METHODS

Retrospective analysis was performed in 311 consecutive patients with slow-fast form and 108 patients with atypical or multiple form of atrioventricular node reentry tachycardia to examine whether variation of P-QRS relation with changes in AH, HA and AH/HA (A = atria; H = His bundle) ratio occurred during tachycardia.

RESULTS

A total of 28 patients, 8 with slow-fast and 20 with atypical or multiple tachycardias, were found to manifest this phenomenon. There were 6 males and 22 females, with an average age of 38+/-16 years. In 10 patients, this phenomenon occurred transiently following electrical induction of the tachycardia. In 15 patients, changes in AH, HA and AH/HA ratio were associated with the occurrence of Wenckebach or 2:1 block proximal to the His bundle (H) recording site without interruption of the tachycardia. In nine patients, three with nonsustained tachycardia and six after administration of adenosine triphosphate, this phenomenon was observed at the termination of the tachycardia. This phenomenon was usually accompanied by a mild lengthening of the tachycardia cycle length.

CONCLUSIONS

Variation of P-QRS relation with or without block may occur during atrioventricular node reentry tachycardia, especially in atypical or multiple-form tachycardias. It was postulated that decremental conduction in the distal common pathway, which exists between the distal link of the reentry circuit and the H, is primarily responsible for this phenomenon.

Late coronary artery stenting in patients with acute myocardial infarction

BACKGROUND

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

METHODS AND RESULTS

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

CONCLUSIONS

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

Surgical closure of atrial septal defect. Minimally invasive cardiac surgery or median sternotomy?

BACKGROUND

Closure of ostium secundum atrial septal defect (ASD) vis median sternotomy (MS) is a simple procedure for most cardiac surgeons. Minimally invasive cardiac surgery (MICS) has recently been applied in the management of intracardiac lesions.

METHODS

We report our experience in surgical closure of isolated ASD via MICS in 60 patients and via MS in 58 patients. There was no difference between these two groups in gender, age, body weight, ratio of systemic to pulmonary blood flow, and pulmonary arterial pressure.

RESULTS

The duration of cardiopulmonary bypass was significantly longer in the MICS group than in the MS group [27 to 126 min (42 +/- 12) and 14 to 158 min (27 +/- 11), respectively; (p < 0.001]. However, the length of incision, incidence of temporary pacemaker wire insertion rate, duration of endotracheal intubation, timing of oral intake, postoperative day drainage amount, incidence of parenteral analgesic injection, postoperative length of stay, and return to normal activity interval were significant shorter and lower in patients of the MICS group than in those of the MS group. All the patients recovered rapidly from the surgery. Follow-up was complete in all patients, with no late complications and no residual shunt.

CONCLUSION

Our results suggest that MICS is a good option for surgical closure of ASD.

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

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

Video-assisted cardiac surgery: preliminary results in Chang Gung Memorial Hospital

OBJECTIVE

To summarize the experience of utilization of video-assisted endoscopy in 91 patients operated on at Chang Gung Memorial Hospital, Taipei, China.

METHODS

From October 1995, through August 1996, 91 patients (44 male and 47 female) received video-assisted cardiac surgery (VACS). Their ages ranged from 1 year to 79.5 years (25.7 +/- 21.7). Indications for surgery were atrial septal defect (59 patients), ventricular septal defect (15), coronary artery disease (4), severe mitral regurgitation (4), severe tricuspid regurgitation (3), thrombosis of mitral mechanical prosthesis (3), left atrial tumor (2), and left ventricular thrombus with dilated cardiomyopathy (1). The VACS was performed through right or left anterior minithoracotomy and guided by video-assisted endoscopic techniques by means of projected images on the video monitor under extracorporeal circulation. The aorta was not cross-clamped and the myocardium was protected by continuous coronary perfusion with hypothermic fibrillatory arrest (rectal temperature 22.6 +/- 4.0 degrees C). Conventional instruments were used.

RESULTS

All lesions were corrected successfully. The bypass time was 27 to 335 minutes (72.8 +/- 52.7). The operative time was 1.3 to 8.5 hours (3.0 +/- 1.7). There were no operative deaths and 3 late deaths. Follow-up was complete in all survivors (6 to 16 months, mean 8.7). Most of them were found to be in NYHA functional I or II.

CONCLUSION

Our preliminary experiences demonstrate that VACS is simple and effective in surgical correction of selected cardiac lesions. Short-term results show good outcomes.

Determinants of tachycardia recurrences after radiofrequency ablation of idiopathic ventricular tachycardia

Clinical and electrophysiologic parameters were analyzed to define the factors potentially related to tachycardia recurrences in 79 patients undergoing successful radiofrequency ablation of idiopathic right or left ventricular tachycardia. It was found that the endocardial activation time at the successful ablation site was the only independent predictor of tachycardia recurrences.

Minimal access surgical techniques in coronary artery bypass grafting for triple-vessel disease

BACKGROUND

Minimal access surgical techniques in coronary artery bypass grafting have been used mainly in the management of single-vessel disease.

METHODS

Fifteen patients, 11 men and 4 women with a mean age of 64.1 years (range, 35.7 to 78.0 years), underwent operation for triple-vessel disease using minimal access techniques. The procedures were performed through a limited left parasternal thoracotomy using femorofemoral extracorporeal circulation. The myocardium was protected by the antegrade infusion of cold blood cardioplegic solution while the aorta was cross-clamped.

RESULTS

Under direct vision, the left saphenous vein grafts were connected sequentially to the diagonal branch, obtuse marginal branch, and posterior descending branch, and the left internal thoracic artery graft was anastomosed to the left anterior descending artery in each patient. The mean aortic cross-clamp time was 86 +/- 17 minutes (range, 67 to 125 minutes). The mean duration of extracorporeal circulation was 112 +/- 22 minutes (range, 82 to 162 minutes). The postoperative course was uneventful in all patients. Follow-up was complete in all patients at a mean of 7.4 months (range, 6.0 to 8.5 months), and there were no late deaths or angina. Coronary angiography in 8 patients showed patent grafts.

CONCLUSIONS

Our experience demonstrates that minimal access surgical techniques in coronary artery bypass grafting are technically feasible and may be an alternative approach in the surgical revascularization of triple-vessel disease.

Application of asymmetric TPX membranes to transdermal delivery of nitroglycerin

In this study, asymmetric poly(4-methyl-1-pentene) (TPX) membranes, fabricated by the dry/wet inversion method, were applied to transdermal delivery of nitroglycerin (NTG), a drug for treating angina pectoris. The flux of NTG through the TPX membrane was measured in vitro by a Franz cell. The results indicate that the NTG flux through asymmetric TPX membranes is strongly dependent on the membrane structure, which can be varied by adding nonsolvents in the casting solution. By adding different kinds of nonsolvents and adjusting the added amounts, membranes with different NTG release rates can be fabricated. It was also found that, with suitable drug formula, the NTG dissolution rate of a prototype TPX patch is comparable to that of a commercial patch, Transderm-Nitro. In addition, the data of NTG flux through a composite of TPX membrane and pig skin are also presented.

Adenosine-sensitive ventricular tachycardia from the anterobasal left ventricle

OBJECTIVES

This study demonstrates that exercise-provocable tachycardia resembling right ventricular outflow tract tachycardia may originate from the anterobasal left ventricle.

BACKGROUND

Reentry is the operative mechanism of idiopathic left ventricular tachycardia, with a QRS complex of right bundle branch block and superior axis that is responsive to verapamil but not adenosine. Whether some mechanism other than reentry is operative in some idiopathic left ventricular tachycardias is unclear.

METHODS

In 4 of 53 consecutive patients with idiopathic left ventricular tachycardia, the tachycardia was sensitive to adenosine. These four patients were women 63, 61, 61 and 31 years old and were the subjects of the present study.

RESULTS

In all four patients, spontaneous tachycardia was related to exercise or emotional stress. The tachycardia displayed atypical left (one patient) or right (three patients) bundle branch block with an inferior axis and marked variation in cycle length. An intravenous bolus of adenosine triphosphate (10 to 20 mg) terminated tachycardia in all four patients. Tachycardia was terminated or prevented in three patients given intravenous or oral verapamil. Atrial or ventricular incremental or extrastimulus testing induced tachycardia in all four patients (three with, one without isoproterenol infusion). Electrically induced tachycardia also demonstrated marked variation in cycle length, which ranged from 230 to 390 ms. Entrainment was not demonstrable with overdrive pacing from multiple sites. Endocardial mapping during tachycardia revealed that the earliest activations were registered 25, 40, 35 and 50 ms before onset of the QRS complex, respectively, from the anterior aspect of the left ventricle just below the mitral annulus, adjacent to the left ventricular outflow tract. High frequency Purkinje spikes were not recorded at this site. Radiofrequency current delivered to this site successfully ablated the tachycardia in three of the four patients.

CONCLUSIONS

Exercise-provocable, catecholamine-mediated, verapamil-responsive, adenosine-sensitive ventricular tachycardia may arise from the anterobasal left ventricle adjacent to the outflow tract.

Regenerative changes in median nerve defects using various rabbit skeletal muscles

We examined the morphological changes of median nerve regeneration which situated to pass through degenerative latissimus dorsi and brachial triceps muscles in rabbits. Morphological observation was performed at 7, 14, 28, 45, 60 and 180 days after the creation of defect of the bilateral median nerves. Regenerative nerve fibers were observed in the residual tubes of left degenerative muscle bridges. In this respect the regenerative effect of the latissimus dorsi was better than that of the brachial triceps. These results suggest that regular and longer muscle fibers as those of latissimus dorsi may contribute to the effective regeneration of nerve.

Successful radiofrequency ablation of idiopathic left ventricular tachycardia at a site away from the tachycardia exit

OBJECTIVES

This study sought to assess the possibility of ablating verapamil-responsive idiopathic left ventricular tachycardia at a site distant from the tachycardia exit and thus to define the tachycardia circuit.

BACKGROUND

The nature of the reentry circuit in idiopathic left ventricular tachycardia is unclear. If the circuit is of considerable size, then it should be possible to ablate the tachycardia at a site distant from the exit site.

METHODS

Electrophysiologic studies and radiofrequency ablation were performed in 27 consecutive patients with verapamil-responsive idiopathic left ventricular tachycardia. In all 27 patients, the tachycardia exit site was defined as the site where the earliest Purkinje potential was recorded > or = 25 ms before the onset of the QRS complex during the tachycardia and where the pace map QRS complex resembled that during the tachycardia. A potential ablation site other than the exit site was then sought around the midseptum, proximal to the exit site. At such sites the tachycardia could be terminated transiently by pressure applied to the catheter tip, without induction of ventricular ectopic beats.

RESULTS

The potential ablation site, other than the tachycardia exit site, was identified in seven male patients (mean [+/-SD] age 31 +/- 12 years, range 13 to 52). Application of the radiofrequency current at this site resulted in termination of the tachycardia within 1 to 5 s (mean 2.9 +/- 1.6), and successful ablation of the tachycardia was achieved in all seven patients (success rate 100%, 95% exact confidence interval 0.5898 to 1). The mean distance between the ablation site and the tachycardia exit site was 3.1 +/- 0.7 cm (range 2.0 to 4.0). A presystolic Purkinje spike was recorded 14 +/- 5 ms (range 8 to 20) before the onset of the QRS complex during the tachycardia. During the follow-up period of 24 +/- 11 months (range 12 to 39), there was no recurrence of tachycardia in these seven patients.

CONCLUSIONS

Successful ablation of idiopathic left ventricular tachycardia can be achieved at sites away from the tachycardia exit site in some patients. This finding suggests that the reentry circuit is likely to be of considerable size, encompassing the middle, inferior and lower aspects of the left interventricular septum.

Cardiac tamponade in Taiwan

We retrospectively reviewed all of the patients who were treated for cardiac tamponade at Linkou Chang Gung Memorial Hospital between January 1991 and December 1995. There were a total of 112 patients (57 males, 55 females) with a mean age of 51 +/- 14 years (53 +/- 15, 49 +/- 13, respectively). Dyspnea was the most common complaint (85%). The mean blood pressure was 129 +/- 24/78 +/- 17 mmHg, and only 8% had a systolic blood pressure of less than 90 mmHg. Sinus tachycardia was the most frequent electrocardiographic finding (72%, 62/86). Diffuse low voltage was noted in 35% (30/86) of the patients and electrical alternans was seen in 17% (15/86). The mean volume of pericardial effusion was 610 +/- 263 ml. Sixty-five percent of the pericardial effusions were bloody, 31% were serosanguineous, 2% were purulent and 2% were chylous. Overall, 54.5% of the patients had malignant diseases. Of the 61 patients who died, 79% had malignancies. Thirty-five (57%) of these 48 patients had lung cancer. The mean survival time from emergent pericardiocentesis was 3.4 months. In conclusion, non-traumatic cardiac tamponade had a poor prognosis because most patients had malignant etiologies. There is still no definitive treatment for recurrent malignant pericardial effusion-induced cardiac tamponade. Percutaneous pericardiocentesis as clinically required may be the most appropriate treatment, since it is questionable whether such subjects should be subjected to the unnecessary pain and suffering associated with an operative procedure, considering their short mean survival time.

Coronary sinus stenosis as a late complication of catheter ablation in Wolff-Parkinson-White syndrome

This report describes a patient who developed stenosis of coronary sinus and cardiac veins five years after application of electric shock currents to the posterior mitral annulus and posteroseptal region of the tricuspid annulus for ablation of a left posterior accessory pathway and a right posteroseptal accessory pathway. This is the first angiographic documentation of coronary sinus stenosis as a late complication of electric ablation of accessory pathway.