PubMed Health⌕ Search

Biomedical subjects

Susan Kim

Publications and source records attributed to Susan Kim.

10 recordsLinked to original sources
PubMed2006

Predictors of appropriate defibrillator therapy among patients with an implantable defibrillator that delivers cardiac resynchronization therapy.

INTRODUCTION: The purpose of this study was to determine predictors of appropriate implantable defibrillator (ICD) therapy among patients with heart failure who are treated with a cardiac resynchronization therapy-defibrillator (CRT-D). METHODS AND RESULTS: Patients enrolled in the Ventak CHF/Contak CD study were treated with a CRT-D device and were required to have NYHA class II-IV CHF, QRS duration > or = 120 msec, and a class I or II indication for an ICD. The study database was retrospectively analyzed during the 6-month postimplant period to identify predictors of appropriate ICD therapy. Five hundred and one of the 581 patients enrolled in the trial had successful device implantation and were included in this analysis. Patients were mostly male (83%), 66 +/- 11 years old, and had coronary artery disease (69%), a mean left ventricular ejection fraction (EF) = 0.22 +/- 0.07, and NYHA class II (33%), III (58%), or IV (9%) CHF symptoms. During 6 months of follow-up, 73 of 501 (14%) patients received an appropriate ICD therapy. Two independent predictors of appropriate therapy were identified: a history of a spontaneous, sustained ventricular arrhythmia (HR = 2.05; 95% CI = 1.31-3.20; P = 0.002) and NYHA class IV CHF (HR = 1.81; 95% CI = 1.10-2.96; P = 0.019). When patients with NYHA class II were excluded from analysis, a history of a sustained ventricular arrhythmia and the presence of NYHA class IV CHF symptoms remained as independent predictors of appropriate ICD therapy. CONCLUSIONS: In a select population of advanced heart failure patients receiving a CRT-D, NYHA class IV CHF was a powerful independent predictor of appropriate ICD therapy. Approximately one-quarter of the patients with NYHA class IV CHF who received a CRT-D device received an appropriate ICD therapy within 3 months after implant. Additional studies are needed to confirm an association between class IV CHF symptoms and an increased frequency of ICD shocks.

Aged↗
PubMed2005

A novel class of in vivo active anticancer agents: achiral seco-amino- and seco-hydroxycyclopropylbenz[e]indolone (seco-CBI) analogues of the duocarmycins and CC-1065.

One achiral seco-hydroxycyclopropylbenz[e]indolone (seco-CBI) (12) and seven achiral seco-amino-CBI (11a-g) analogues of CC-1065 and the duocarmycins were designed, synthesized and evaluated for their DNA-binding and anticancer properties. These compounds contain a core 2-chloroethylnaphthalene structure and they do not have a stereocenter. From thermal cleavage gel analyses, compounds 11a-g and 12 demonstrated similar covalent sequence specificity to adozelesin 3 and the racemic seco-CBI-TMI 4 for binding to the 5'-AAAAA(865)-3' site. Continuous exposure of human (K562) and murine (B16, L1210 and P815) cancer cell lines to the compounds demonstrated their significant cytotoxicity, with IC50 values in the sub-micromolar range. Generally, a good leaving group on the ethyl moiety and a free amino or hydroxyl group on the naphthyl moiety are essential for activity. According to NCI's cytotoxicity screen, compounds 11a and 12 were active against human cancer cell lines derived from lung, colon, melanoma, renal system, and breast. At the respective doses of 15 and 20 mg/kg (administered via an ip route), compounds 11a and 12 inhibited the growth of murine B16-F0 melanoma in C57BL/6 mice, with minimal toxicity, and 11a gave a significant anticancer effect. The in vivo anticancer activity of compound 11a was confirmed in a human tumor xenograft study (advanced stage SC-OVCAR-3 ovarian cancer growing in scid mice). Finally, compound 11a was not toxic to murine bone marrow cell growth in culture at a dose that was toxic for the previously reported compound 4.

1-Naphthylamine↗
PubMed2005

Termination of epicardial left ventricular tachycardia by pacing without global capture.

It is generally accepted that the diagnosis of an epicardial origin of ventricular tachycardia (VT) can be made indirectly by observing VT termination during ablation on the epicardial surface of the heart. There is a caveat, however, which is that termination of VT during radiofrequency current application on the epicardial surface could be due to extension of the lesion beyond the epicardium. Therefore, successful ablation of VT using an epicardial approach does not necessarily prove the reentrant circuit is located superficially. We present a case of a 44-year-old man with VT storm who demonstrated successful termination of VT with radiofrequency current application on the epicardial surface of the heart. This site corresponded to a site where pacing during VT resulted in termination of VT without global capture. Isolated mid-diastolic potentials were only seen at this site as well. We hypothesize that the finding of termination of VT by pacing without global capture supports the argument that the site of pacing is a critical part of the VT circuit.

Adult↗
PubMed2005

Implications and outcome of permanent coronary sinus lead extraction and reimplantation.

OBJECTIVE: We examined the implications and outcome of coronary sinus (CS) lead removal including the feasibility of laser use within the CS. BACKGROUND: Cardiac anatomy and lead interactions are more complex with the advent of biventricular pacemakers and atrial cardioverters requiring permanent lead/shocking coil placement in the coronary sinus and its branches. METHODS: Fifty-five permanent cardiac leads were extracted during 2003 in 28 consecutive patients. Our study population included a 10/55 (18%) subset (all males; age 73 +/- 6 years; EF = 0.24 +/- 0.09) that underwent CS (1/10) or vein branch (9/10) lead extraction. Leads were extracted with an excimer laser sheath (n = 4) or by direct traction (n = 6). Median times between implantation and lead removal were 9.5 months (range 5-59) in the laser group and 3 months (range 3-4) in the direct traction group. Indication for extraction was infection (n = 4), dislodgement (n = 3), diaphragm stimulation (n = 2), and elevated threshold (n = 1). The CS was divided into distal, mid, and proximal segments by venogram. RESULTS: Entry of the laser sheath into the CS was necessary in three of four laser patients. The two distal CS laser cases (left lateral CS coil and anterior-lateral left ventricular (LV) lead) required both 14- and 12-Fr sheaths, separately. The proximal CS laser case (posterior-lateral LV lead) required a 12 Fr sheath. The remaining laser patient required a 12-Fr sheath to pass to the mid SVC. There were no procedural complications as a result of CS lead extraction. Reimplantation of a CS lead was attempted in 7/10 patients at a median of 4 days (range 1-300). CS venograms were available for review in patients before initial implantation (6/10) and after extraction (7/10). The postextraction venograms demonstrated complete occlusion of the vein from which the lead was extracted, and its distal branches, which were unusable in 5/10 (50%). The vein occlusions were present in patients with indwelling leads for greater than 3 months and were independent of extraction method. CONCLUSIONS: Laser lead extraction in the coronary sinus appears feasible in carefully selected cases with mandatory indications. However, special intraoperative monitoring and echocardiographic imaging with surgical backup ready is strongly recommended. Target vein selection may be limited for the purpose of reimplantation when leads are indwelling for greater than 3 months.

Aged↗
PubMed2005

Update on pediatric vasculitis.

PURPOSE OF REVIEW: The purpose of this review is to provide an overview of the recent research and progress made in the field of pediatric vasculitis. RECENT FINDINGS: Over the past year, researchers have described several polymorphisms in Henoch-Schonlein purpura and Kawasaki Disease as well as the association between various vasculitides and infections. International and multidisciplinary efforts in Kawasaki Disease have resulted in recommendations for its diagnosis, treatment, and long-term management to improve patient care and further increase global collaboration. Researchers are investigating the role of inflammation and its role in endothelial health and atherosclerosis. Treatment regimens continue to improve, with the use of different immunosuppressive medications; however, we continue to have incomplete treatment successes. SUMMARY: Vasculitides are rare conditions with significant morbidity and mortality whose prognosis has improved with newer diagnostic modalities and treatments; however, we continue to have insufficient knowledge of vasculitides and lack unambiguous diagnostic criteria. As technology continues to progress it is clear that a single cause of these diseases may be an oversimplification: the genetic makeup of individuals, as well as various environmental exposures, are of vital importance in the pathophysiology and evolution of disease processes, as well as response to therapy. Efforts should continue to improve international multicenter collaboration and interdisciplinary efforts to help solve this ever-growing puzzle.

Bacterial Infections↗
PubMed2005

Seizure in a child after an acute ingestion of levothyroxine.

BACKGROUND: Unintentional ingestion of thyroid hormone preparations is a common occurrence reported to poison control centers. These incidents rarely result in serious outcomes. We report a case of a tonic-clonic seizure occurring in a child after ingestion of a maximum of 3.6 mg of levothyroxine. CASE REPORT: A 3.5-year-old boy ingested up to 41 tablets of 88 microg levothyroxine, which was not discovered until the following day. On the third day after the ingestion, he had a single 5- to 10-minute tonic-clonic seizure. Laboratory results were total thyroxine greater than 24.0 microg/dL; free thyroxine, 5.5 ng/dL; and thyroid-stimulating hormone, 0.03 mU/L. On the following day, the patient had diarrhea and was hyperactive; heart rate was 144 beats per minute, and mild hyperreflexia was noted on neurological examination. Symptoms were resolved 3 days later. CONCLUSION: This is the second case report of a seizure occurring in a child after an unintentional ingestion of levothyroxine. The maximum amount possibly ingested is much lower than that previously reported. Pediatric ingestion of less than 5 mg of levothyroxine may result in serious outcomes.

Child, Preschool↗
PubMed2004

Dendritic guidance.

Like axons, dendrites need guidance for proper orientation and positioning within the brain. Guidance determines synaptic connectivity as well as the strength of transmission. Recent in vivo studies have demonstrated that several cell-surface receptors, previously known as axon guidance molecules, are also responsible for the directed outgrowth of dendrites. Collectively, these studies reveal that the function of guidance molecules in individual neurons and individual processes is diverse and likely to be specifically regulated. Here, these studies are reviewed and emerging issues and implications are discussed.

Animals↗
PubMed2003

Robo and Frazzled/DCC mediate dendritic guidance at the CNS midline.

Neuronal connectivity is established by the axo-dendritic polarity, correct guidance and targeting of neurons. Unlike for axons, the mechanisms responsible for directed outgrowth of dendrites are not well understood. Using single-cell labeling, we describe specific guidance defects in dendrites of identified neurons in frazzled, robo, netrin and commissureless mutant embryos of Drosophila melanogaster. We found that the cell-surface molecules Frazzled and Robo work as guidance molecules not only for axons but also for dendrites as they navigate within the CNS. Furthermore, we report that each neuron showed a cell-autonomous and independent use of guidance molecules.

Animals↗
PubMed2003

Synthesis and biological evaluation of novel diaziridinylquinone-acridine conjugates.

The synthesis and biological evaluation of a homologous series of conjugates (9-13) of 2,5-diaziridinylbenzoquinone (DZQ) and 9-carbonylacridine, a DNA intercalating moiety, via a polymethylene unit (n=2-6) are described. In addition, the non-acridine compound 14, analogous to compound 12, and the 5-methyl-DZQ derivatized conjugate 15, an analog of compound 10, were also prepared. Through a Comet assay, compounds 9-13 were shown to produce DNA interstrand cross-links at submicromolar concentrations, consistent with K562 leukemia cells accumulating in the G2/M stage in the cell cycle. The cytotoxicity of compounds 9-15 was examined using a MTT assay on several human cancer cell lines, including chronic myeloid leukemia K562, the non-small cell lung cancers H596 and H460, and colon carcinoma cells BE and HT29. H460 and HT29 are rich in DT-diaphorase (DTD), and H596 and BE cells have negligible amounts of functional DTD. Under continuous exposure of drugs, except to the non-aziridine compound 19b, the IC50 values of all other compounds were determined to be in the range of 0.3-11.3 nM. Compound 10, which has a propyl linker group, was subjected to in vivo studies. When BDF1 mice with established mouse mammary carcinoma were treated with compound 10 (2 mg/kg at day 1 and 5 mg/kg at day 7), a significant delay (9-10 days) in cancer growth was recorded when compared to untreated controls. Furthermore, administration of compound 10 to nu/nu BDF1 mice bearing human lung cancer H460 xenograft (1.5 mg/kg for 10 for five consecutive days from day 13 and 17) also showed a significant reduction in tumor growth compared to untreated controls. The half-life of compound 10 in the presence of five different peptidases (porcine esterase, carboxypeptidase A, B and Y, and pepsin) was determined to be between 30 and 60 h.

Acridines↗