2-[对-(二甲氨基)苯乙烯]氯化甲基吡啶对大鼠心电图、豚鼠左心房收缩及乳头肌动作电位的影响

2-[对-(二甲氨基)苯乙烯]氯化甲基吡啶(DSPM-Cl),是由氯取代2-[对-(二甲氨基)苯乙烯]碘化甲基吡啶(DSPM)上的碘而得。本文应用心电图、机械收缩描记方法及细胞内标准微电极技术,研究DSPM-Cl对大鼠心电图(ECG)、豚鼠心房肌量效曲线及对豚鼠乳头肌快反应动作电位(AP)、高钾除极慢反应动作电位(SAP)的影响。结果显示,DSPM-Cl(2mg·kg^-1)对大鼠有明显的负性频率、负性传导作用,分别使PP间期、PR间期延长达66.2%(P<0.01),17.0%(P<0.01),50μmol·L^-1能明显抑制左心房收缩力,非竟争性拮抗Iso及CaCl₂对豚鼠左心房的正性肌力作用,PD^2'分别为4.6,4.34,100μmol·L^-1DSPM-Cl延长动作电位时程APD₉₀,有效不应期(ERP),降低高钾除极豚鼠乳头肌0期最大上升速率Vmax,其作用与Ver相似,提示DSPM-Cl可能为钙拮抗剂。     

Focal liver masses: differential diagnosis with pulsed Doppler US

Duplex Doppler ultrasound (US) was used in 68 consecutive patients with focal liver lesions, including 12 hepatocellular carcinomas, one cholangiocarcinoma, 37 metastases, 15 hemangiomas, one hemangioendothelioma, and two focal nodular hyperplasias. Of the hepatocellular carcinomas, six were diffusely hyperechoic, two were hypoechoic, two were single hyperechoic lesions, and two were multifocal and hyperechoic. All ten tumors with Doppler shifts of 5 kHz or above proved to be hepatocellular carcinomas. The other two hepatocellular carcinomas showed Doppler shifts of 3 kHz. In contrast, no hemangioma showed shifts above 0.7 kHz, and ten of the 15 gave no detectable signal. Of the metastases, 20 gave no signal and 17 had signals of up to 4 kHz. Three-kilohertz signals were also obtained from a cholangiocarcinoma, a hemangioendothelioma, and focal nodular hyperplasia. Correlation with angiographic findings suggested that the high-velocity Doppler signals were associated with large pressure gradients due to arteriovenous shunting. Duplex Doppler US can therefore aid in the differential diagnosis of diffuse and focal liver lesions.     

Multiple Subclinical Syringomatous Proliferations Encountered during Mohs Surgery for Basal Cell Carcinoma

BACKGROUND: Examination of Mohs surgery frozen sections may lead to discovery of incidental benign neoplasms such as syringomas. OBJECTIVE: An unusual occurrence of numerous subclinical syringomatous proliferations discovered during Mohs surgery for a basal cell carcinoma that posed a diagnostic and management dilemma is reported. METHODS: Clinical records and histologic sections are examined. RESULT: Multiple syringomatous proliferations were noted around a basal cell carcinoma during Mohs surgery. A few foci were atypical appearing and focally extending into the deep dermis causing a diagnostic dilemma. All atypical syringomatous proliferations were excised. Evaluation of final Mohs margins by permanent sections and biopsies of normal-appearing facial skin showed multiple benign syringomas. CONCLUSION: Although solitary subclinical syringomas have been described in association with basal cell carcinomas, the occurrence of multiple syringomas and syringomatous proliferations has not been previously reported. Dermatologists should be aware of the existence of this phenomenon and consider permanent section evaluation to better determine nature of unusual incidental tumors identified in frozen sections during Mohs surgery.     

Neonatal treatment with 192 IgG-saporin produces long-term forebrain cholinergic deficits and reduces dendritic branching and spine density of neocortical pyramidal neurons

The role of basal forebrain-derived cholinergic afferents in the development of neocortex was studied in postnatal rats. Newborn rat pups received intraventricular injections of 192 IgG-saporin. Following survival periods ranging from 2 days to 6 months, the brains were processed to document the cholinergic lesion and to examine morphological consequences. Immunocytochemistry for choline acetyltransferase (ChAT) and in situ hybridization for ChAT mRNA demonstrate a loss of approximately 75% of the cholinergic neurons in the medial septum and nucleus of the diagonal band of Broca in the basal forebrain. In situ hybridization for glutamic acid decarboxylase mRNA reveals no loss of basal forebrain GABAergic neurons. Acetylcholinesterase histochemistry demonstrates a marked reduction of the cholinergic axons in neocortex. Cholinergic axons are reduced throughout the cortical layers; this reduction is more marked in medial than in lateral cortical areas. The thickness of neocortex is reduced by approximately 10%. Retrograde labeling of layer V cortico-collicular pyramidal cells reveals a reduction in cell body size and also a reduction in numbers of branches of apical dendrites. Spine densities on apical dendrites are reduced by approximately 20-25% in 192 IgG- saporin-treated cases; no change was detected in number of spines on basal dendrites. These results indicate a developmental or maintenance role for cholinergic afferents to cerebral cortical neurons.