MEG Characterization of Spontaneous Alpha Rhythm in the Human Brain

The present piece of research studied the spontaneous alpha rhythm of the human brain by combining the use of a whole-cortex neuromagnetometer and Magnetic Resonance Imaging. Single trials of spontaneous brain activity were recorded from ten human subjects asked to rest, with their eyes either closed or open, in relaxed wakefulness. MEG measurements were conducted over a period of one and a half years. The replicability of the results was confirmed for eight subjects out of ten. For three subjects, the alpha rhythm did not show any reductions due to the opening of the eyes. Both field map pattern and location of the estimated source were persistently stationary during each of the bursts of oscillations of the alpha rhythm. Dipoles were concentrated in clusters, indicating the existence of several spatially distributed sources. The calcarine fissure, the parieto-occipital sulcus and the surrounding occipital and parieto-occipital areas were identified as cortical sites of the brain where the alpha rhythm may originate. For four subjects, the majority of the sources were located near or in the calcarine fissure, while for five subjects, they were located near or in the parieto-occipital sulcus and for the remaining subject they were equally divided between the two generation sites.     

EEG asymmetries may be affected by cranial and Brain parenchymal asymmetries

Summary The plagiocephaly index, an index that reflects an underlying anatomic asymmetry of the brain, was assessed in ten schizophrenic patients and its values were correlated with the lateral distribution of quantitatively evaluated EEG. The correlations between the index and alpha power at F7 were significant, positive for frontal asymmetry (frontal bulging) and negative for occipital flattening. We then studied ten normal subjects in an attempt to illuminate the contribution of several cephalic and cranial variables to the imbalance of alpha-afterdischarges (AD) of VEP recorded at O1–O2. The asymmetry index of AD was computed and correlated with asymmetries of CT-derived measures of occipital bone thickness, occipital lobe width, mastoid area, and sulcal asymmetry (the asymmetry of intraparietal sulcus location from the longitudinal fissure). With the exception of the sulcal variable all measures significantly covaried with alpha AD. These findings caution that it may be important to determine cranial and brain parenchymal asymmetries where brain laterality is pertinent to studies of EEG.     

Pancreatoblastoma with marked elevation of serum alpha-fetoprotein

Summary The autopsy findings in a pancreatoblastoma in a 7-year-old Japanese girl is reported. The tumour was in the head and body of the pancreas, and was associated with diffuse carcinomatous peritonitis and hepatic and pulmonary metastases. There was marked elevation (more than 10000 ng/ml) of serum alpha-fetoprotein (AFP). Histopathologically the tumour was composed of solid epithelial elements with fibrous stroma, showing acinar arrangement, squamoid clusters and tubular structures. The epithelial elements contained numerous fine PAS positive granules in the cytoplasm. Immunocytochemical results suggested epithelial differentiation with positivity to alpha-1-antitrypsin (AAT), keratin, CA19-9, and AFP. No endocrine elements were recognized. Characteristic feature of this tumour are discussed and compared with prevoius reports.     

Physiological Correlates of Mental Activity: Eye Movements, Alpha, and Heart Rate During Imagining, Suppression, Concentration, Search, and Choice

Rapid eye movements (REMs), EEG alpha, and tonic heart rate (HR) were measured during 6 types of cognitive tasks—imagining a liked person, suppressing thoughts of the person, searching one's mind for alternative solutions, arithmetic involving little concentration, problems involving high concentration, and choosing a preferred activity. The latter 3 required verbalization, the former 3 did not. Only suppression and search did not differ significantly from each other on at least one physiological variable. Imagining, suppression, and search yielded few REMs, high alpha, and low HR. High concentration yielded many REMs, low alpha, and high HR. Choice yielded many REMs, low alpha, and intermediate HR. Low concentration yielded few REMs, low alpha, and high HR. Suppression produced somewhat less alpha than imagining but did not differ significantly in REMs.     

Ovarian Sertoli-Leydig cell tumour with raised serum alpha fetoprotein

Summary A case of ovarian Sertoli-Leydig cell tumour with a raised serum alpha fetoprotein in reported. The patient first presented at the age of 27 years with a history of 6 years' amenorrhoea followed by 3 months irregular vaginal bleeding. A ovarian tumour was found and excised and shown microscopically to be a spindle cell malignant tumour. The patient was treated with chemotherapy and had a complete response. Thirty months after first presentation there was a recurrence in the pelvis which microscopically showed the typical features of a Sertoli-Leydig cell tumour. Six months later a second recurrence had the microscopic appearance of a lipid cell tumour. A raised serum alpha fetoprotein was found at the time of the second recurrence and immunohistochemistry showed this protein in the Leydig and luteinized cells of the recurrent tumours but not in the spindle cells of the original ovarian neoplasm.     

杭州地区8516例孕中期妇女产前筛查回顾性分析

目的分析杭州地区孕中期妇女运用甲胎蛋白(AFP)和游离绒毛膜促性腺激素β亚基(Free-βhCG)进行胎儿先天缺陷产前筛查的结果;并据此修正两筛查指标的孕周中位数值。方法对杭州地区孕14~20w的妇女进行产前AFP和Free-βhCG的检测。胎儿先天畸形由染色体核型分析、B超检查确诊,或经引产证实。应用非线性加权回归求得本地区两筛查指标的中位数,并计算中位倍数值进行分布拟合。比较标化前后检测效果。结果8516例受检孕妇,共筛查出唐氏综合征3例、爱德华综合征2例,神经管畸形7例,其他胎儿异常17例;杭州地区孕中期妇女AFP及Free-β-hcG中位数比欧洲妇女分别高18%和14%;用修正后的中位数重新分析,孕中期假阳性率降低。结论血清AFP、Free-βhcG联合检测,可作为杭州地区孕中期妇女产前筛查优选项目。而根据地域人群的差异,对Mu ltiCalc软件内嵌中位数进行修正后更适于杭州地区孕中期妇女的产前筛查。     

Placental site trophoblastic tumor of the mediastinum

Choriocarcinoma has been described as the most frequent subtype of mediastinal germ cell tumors showing trophoblastic differentiation. We report a unique case of a placental site trophoblastic tumor, which developed in the mediastinum of a 14-year-old boy 2 years after the resection of a mature teratoma. The recurrent tumor was composed of a grossly hemorrhagic and necrotic mass. Histologically, diffusely infiltrating large polygonal cells with focal nodular growth and a teratomatous part containing mature intestinal, respiratory, and squamous epithelium with adjacent cutaneous adnexal structures were found. The typical morphologic features included vessel wall infiltration by the neoplastic cells with fibrinoid deposits and geographic necroses within the tumor masses. Characteristic diffuse positivity for melanoma cell adhesion molecule and human leucocyte antigen G was found on immunohistochemical investigation, confirming the diagnosis of placental site trophoblastic tumor. The patient died 1 year later after polychemotherapy. The outcome of this rare tumor is similar to the reported poor clinical outcome in patients with mediastinal choriocarcinomas.     

The role of the splanchnic circulation in the regulation of total intravascular volume during alpha adrenergic receptor stimulation

Previous studies have not defined the contribution of the splanchnic circulation to the total intravascular volume change associated with selective alpha adrenergic receptor stimulation. Since the splanchnic circulation is responsible for the total volume changes associated with other types of selective autonomic receptor stimulation, the present study was undertaken to examine the influence of alpha adrenergic receptor stimulation on splanchnic intravascular volume, the hemodynamic mechanism responsible for the splanchnic volume change, and the contribution of the splanchnic volume change to the change in total volume. In 35 anesthetized dogs, blood from the vena cavae was drained into an extracorporeal reservoir and returned to the right atrium at a constant rate so that changes in total intravascular volume could be measured as reciprocal changes in reservoir volume. Phenylephrine infusion (100 g/min) for 20 min in 28 dogs was associated with a decrease in total volume of 64±17 (SEM) ml (P<0.0001). The response was abolished by either alpha adrenergic blockade or evisceration but was not attenuated by beta adrenergic blockade, sinoaortic baroreceptor denervation, ganglionic blockade, or splenectomy. In 5 animals with separate splanchnic perfusion and drainage, total and splanchnic volumes decreased 59±8 ml (P<0.0001) and 317±20 ml (P<0.0001), respectively, while transhepatic vascular resistance increased 17±4 cm H₂O·min/l (P<0.0001). These responses were abolished after alpha adrenergic blockade. Thus, splanchnic volume decreases with alpha adrenergic receptor stimulation, despite an increase in hepatic resistance to splanchnic, venous outflow. The splanchnic volume decrement is entirely responsible for the total volume decrement.The study was supported by NHLBI Grant 1 R23-HL27185, Grant 11-203-812 from the American Heart Association of Greater Hartford, Inc., and the Duberg Cardiovascular Research Fund. Dr. Rutlen was the Duberg Scholar in Cardiovascular Disease when the study was performed.This work was presented in part at the 1982 Scientific Sessions of the American Heart Association (Circ. 66:II-311)     

Interaction of the pesticide chlordimeform with adrenergic receptors in mouse brain: an in vitro study

Chlordimeform (N'(4-chloro-o-tolyl)-N, N-dimethylformamidine; CDM) is a formamidine insecticide/acaricide whose major active metabolite is its N-monomethyl analog, desmethylchlordimeform, (DCDM). While their pesticidal action in invertebrates appears to be related to activation of octopamine receptors, their mechanism of action in mammals has not been established. Because of similarities between octopamine and adrenergic receptors and suggestions of CDM and DCDM action on adrenoceptors, the in vitro interactions of CDM and DCDM with adrenoceptors were studied. In mouse brain membrane preparations CDM inhibited the binding of [³H]-clonidine to alpha₂- adrenoceptors and of [³H]-WB4101 to alpha₁-adrenoceptors with IC₅₀ values of 18.2 and 87 M, respectively. DCDM was a much more potent inhibitor, with IC₅₀ values toward alpha_2–, and alpha₁-adrenoceptors of 44 nM and 1 M, respectively. Both compounds were only weak inhibitors of the binding of [³H]-dihydroalprenolol to beta-adrenoceptors and of [³H]-quinuclidinyl benzilate to muscarinic receptors and were inactive toward benzodiazepines and gamma aminobutyric acid (GABA_A) receptors. Inhibition of [³H]-clonidine binding by both compounds was competitive, as indicated by a decreased receptor affinity without changes in receptor density. Interaction of CDM and DCDM with [³H]-WB4101 binding, on the other hand, was more complex, and not of the competitive type. These results show that CDM and its metabolite DCDM can interact directly in vitro with alpha-adrenergic receptors, suggesting that these receptors could mediate some of the effects of CDM and DCDM in vivo.     

Nucleus locus coeruleus: Evidence for α1-adrenoceptor mediated hypotension in the cat

Summary The Bezold-Jarisch reflex characterized by hypotension and bradycardia was elicited in anaesthetized artificially respired dogs (pretreated with a beta-adrenoceptor antagonist) using capsaicin 10 g/kg (i.v.). Intracisternal administration of the highly selective clonidine-like alpha₂ adrenoceptor agonists B-HT 920 (10 g/kg) or B-HT 933 (30 g/kg) significantly facilitated this reflex bradycardia. The involvement of central alpha₂-adrenoceptors is suggested as intracisternal administration of the alpha₂ adrenoceptor blocking drugs yohimbine (50 g/kg) and piperoxan (50 g/kg) antagonized this facilitation. B-HT 920 also facilitated the vagally mediated baroreceptor reflex to the hypertensive effect of intravenous noradrenaline (3 g/kg). Although the Bezold-Jarisch reflex and the baroreceptor reflex have different afferent pathways, both reflexes may either converge into a common pathway or have separate neuronal chains within the medulla; however, this study indicates that both have a similar central modulatory system stimulated by alpha₂ adrenoceptors.