Surgical division of Wolff-Parkinson-White pathways utilizing the closed-heart technique: a 2-year experience in 47 patients

Kent bundle interruption for ventricular preexcitation has been successfully accomplished utilizing several different surgical techniques. The external closed-heart technique of Guiraudon combining surgical dissection and cryoablation has been used to interrupt 52 accessory pathways in 47 consecutive patients since May, 1985. The 35 male and 12 female patients ranged in age from 10 to 67 years (mean, 30 years). There were 25 left free wall, 13 right free wall, 13 posterior septal, and 1 anterior septal accessory pathways. Preoperative and intraoperative electrophysiological studies were performed in all patients to induce the arrhythmia and localize all accessory pathways. The operation consisted of dissection of the atrioventricular fat pad. Following this, the delta wave and retrograde accessory pathway conduction disappeared, thereby indicating successful pathway ablation. In 4 patients with right-sided accessory pathways, interruption of the pathway required cryoablation. Cryolesions (made with cryoprobe at -60 degrees C for two minutes) were created in the region of the accessory pathway insertion. All accessory pathways were successfully ablated without any deaths or heart block. Concomitant surgical procedures were performed in 4 patients. Two patients required a second operation the next day for an accessory pathway not found at the initial operation. Three patients had postpericardiotomy syndrome, and 4 had recurrent atrial fibrillation requiring therapy. The remaining patients have had no arrhythmia recurrence and have remained drug free after a follow-up of 1 month to 22 months (mean, 12.5 months). We conclude that the closed-heart technique of accessory pathway ablation is safe and reproducible, obviates the necessity for aortic cross-clamping and cardioplegic arrest, and allows instantaneous monitoring of conduction over the pathway.     

UVB radiation induces phosphorylation of the epidermal growth factor receptor, decreases EGF binding and blocks EGF induction of ornithine decarboxylase gene expression in SV40-transformed human keratinocytes

Abstract We previously demonstrated that epidermal growth factor (EGF) induces a several-fold increase in ornithine decarboxylase (ODC) activity and the steady-state level of ODC mRNA in cultured SV40-transformed human keratinocytes (1). Pretreatment of cell cultures with ultraviolet B (UVB) radiation resulted in a reduction of EGF-induced ODC activity. To determine whether UVB inhibits the accumulation of ODC mRNA by EGF, cells were pretreated with 20 mJ/cm² UVB or sham-irradiated and then incubated with 100 ng/ml EGF. Northern blot analysis revealed that UVB irradiation entirely blocked the EGF induction of ODC mRNA. Since the binding of EGF to its plasma membrane receptor is the first step in initiating a biological response, the effect of UVB on EGF binding was evaluated. UVB treatment of cultured keratinocytes resulted in an immediate and dose-dependent reduction of EGF binding. Scatchard analysis revealed thai the reduction of EGF binding was due to a 52% decrease in the number of available receptors, from 6.2 × 10⁴/cell to 3.0 × 10⁴/cell. However, UVB decreased the EGF-binding affinity very little (Kd = 0.60 nM in control and Kd=0.75 nM in UVB-treated Z114 cells). In addition, UVB did not alter the rate of EGF internalization. These data suggest that UVB blocks the signal transduction pathway of EGF that is involved in regulation of ODC gene expression. Immunoblot analysis of extracts from irradiated cells showed that UVB induced tyro-sine phosphorylation of EGFR and that the quantity of EGFR protein was unaffected by UVB treatment. Phosphorylation of EGFR may be responsible for decreased binding of EGF to its receptor.     

Multiple hemopoietic lineages are found after stimulation of mouse bone marrow precursor cells with interleukin 3

When the murine T-lymphocyte clone L2 is stimulated with concanavalin A, it secretes at least two distinct factors that affect hemopoietic precursor cells, interleukin 3 (IL3) and granulocyte/macrophage colony-stimulating factor (GM-CSF). IL3 accounts for approximately 10% of the colony-stimulating activity in L2-cell-conditioned medium. The IL3 secreted by L2 cells is similar antigenically to the IL3 secreted by WEHI-3 cells. Like the IL3 from WEHI-3 cells, IL3 secreted by L2 cells does not bind to DEAE Sephacel and can be separated from the L2-cell GM-CSF, which does bind to DEAE. By assessment of the functional, morphologic, surface phenotypic, and cytochemical characteristics of bone marrow cells 6 days after stimulation with IL3 in liquid culture, four hemopoietic lineages were found, including macrophage, neutrophilic granulocyte, megakaryocyte, and basophil/mast cell. In addition, when bone marrow cells were stimulated with IL3 in semisolid medium, several types of colonies were found, including mixed colonies containing macrophage, megakaryocyte, and granulocyte lineages.     

A performance analysis of an extracorporeal shock wave lithotripter: spatial pressure distribution and the effects of lithotripter voltage, electrode life, and tissue attenuation

The Dornier MPL-9000 lithotripter was analyzed as a function of lithotripter voltage, electrode efficiency, and bovine muscle attenuation. The maximum pressure at 20 kV measured 65 +/- 4 MPa (mean +/- SD). The region containing 50% of the maximum pressure was a cylindrical volume with a diameter of 2.5 cm and a height of 7 cm. Pressure varied in a linear fashion with lithotripter voltage (r = 0.996). The average pressure produced by an electrode throughout the course of 2,200 shock waves was 78% of its maximum pressure. Shock wave pressure was reduced from 65 +/- 4 MPa to 49 +/- MPa, 44 +/- 3 MPa, and 44 +/- 1 MPa with 1-, 2-, and 3-cm thickness of intervening bovine muscle, respectively. There was a statistically significant decrease in pressure when muscle was interposed, but there was no significant difference in reduction of pressure between 1, 2, and 3 cm of muscle (ANOVA, Newman-Keuls, alpha = 0.01). Frequency spectral analysis revealed the major contribution to the shock wave comes from 0-200 kHz with a peak near 50 kHz. Major frequency intensities were reduced with a decrease in lithotripter voltage, attenuating tissue, and distance away from the center of the focal zone.     

Distinctive gene expression profiles by cDNA microarrays in endometrioid and serous carcinomas of the endometrium.

Endometrial carcinomas are classified by their morphology into two major subtypes. Endometrioid carcinomas (type I) are generally estrogen dependent, well-differentiated, superficially invasive, and have a good outcome. Serous carcinomas (type II) are hormone independent, frequently deeply invasive and widely metastatic, and have a poor prognosis. Microarray technology and analysis allows us to determine if the global gene expression profiles of these two subtypes correlate with their morphologic phenotype. Fresh tissue from 18 endometrial carcinomas was studied: 7 well-, 2 moderately, and one poorly differentiated endometrioid, 4 serous carcinomas, and 4 high-grade mixed endometrioid-serous carcinomas. Labeled cDNA probes were synthesized (Cy5 for tumor, Cy3 for reference) and applied to microarrays containing 18,098 cDNA clones or ESTs. A pool of equal amounts of total RNA from each tumor served as the reference RNA. By unsupervised cluster analysis, the endometrioid carcinomas clustered together and were separate from the serous carcinomas. The high-grade mixed carcinomas clustered with the serous carcinomas. Using a statistical algorithm based on gene expression pattern and conducting a supervised analysis of the two defined groups, we have identified 315 genes that statistically differentiate type I from type II endometrial carcinomas. In addition to corroborating the predicted overexpression of known markers (e.g., ras and catenin in endometrioid carcinomas), the cDNA microarray technique has revealed novel alterations in gene expression relevant to cell cycle, cell adhesion, signal transduction, apoptosis, and tumor progression not previously implicated in endometrial carcinomas. For serous carcinomas, these include aldolase, desmoplakin, integrin-linked kinase, PKC, and metallopeptidase. In conclusion, the gene expression profiles of type I and type II endometrial carcinomas are different. Refinement of these profiles will permit more accurate diagnostic tumor classification and the development of prognosis assays.     

Flow cytometry in hairy cell leukemia before and during interferon alfa-2b therapy

Mononuclear cells from 15 patients with hairy cell leukemia were studied before and during therapy with interferon alfa-2b (IFN) by regular peripheral blood differential counts and flow cytometry, using a panel of monoclonal antibodies (Moab). Seven leukemic phase patients (Group 1) had a mean leukocyte count of 48,870/microliter at entry with a mean absolute hairy cell (HC) count of 40,100/microliter. After 3 months on IFN, both parameters decreased significantly (WBC 3,500/microliter; HC count 130/microliter). In eight patients with a cytopenic form of the disease (Group 2) the mean leukocyte count rose from 2950/microliter to 3890/microliter while the mean absolute HC count decreased from 300/microliter to 120/microliter. The morphologic shifts correlated well with changes in the Moab reaction pattern. In Group 1 the activity of all Moab decreased significantly. In Group 2, only cells expressing Leu 3a and Leu 11a (a marker of natural killer cells) showed a significant shift, the latter increasing from 170/microliter to 360/microliter. This increase in natural killer cell antigen expression was not obvious based on routine morphologic observations alone. We show that flow cytometry may be a useful adjunct in monitoring the response of HCL to therapy. Changes in populations of cells that may be difficult to discriminate on morphologic grounds alone may be observed.     

30例感染性心内膜炎的临床分析

目的:探讨感染性心内膜炎(IE)的病因,致病微生物的变迁及抗生素的选择。方法:对1995年5月～2003年8月间住院的30例IE患者的临床资料进行回顾性分析。结果:风湿性心脏瓣膜病为其主要的基础心脏病变。链球菌在致病微生物中依然居首位,但凝固酶阴性葡萄球菌(CNS)等其它菌种逐渐增多,且对青霉素耐药发生率高,为临床诊治造成困难。结论:对于IE患者应尽可能早期明确诊断,早期选用有效的抗生素。CNS在IE的致病微生物中的地位有待进一步提高。