Simple two-electrode biosignal amplifier

A simple, cost effective circuit for a two-electrode non-differential biopotential amplifier is proposed. It uses a ‘virtual ground’ transimpedance amplifier and a parallel RC network for input common mode current equalisation, while the signal input impedance preserves its high value. With this innovative interface circuit, a simple non-inverting amplifier fully emulates high CMRR differential. The amplifier equivalent CMRR (typical range from 70–100 dB) is equal to the open loop gain of the operational amplifier used in the transimpedance interface stage. The circuit has very simple structure and utilises a small number of popular components. The amplifier is intended for use in various two-electrode applications, such as Holter-type monitors, defibrillators, ECG monitors, biotelemetry devices etc.     

Ullrich-Turner syndrome with a small ring X chromosome and presence of mental retardation

Since some patients with Ullrich-Turner syndrome (UTS) have mental retardation, we reviewed our experience to look for a high-risk subgroup. Among 190 UTS and gonadal dysgenesis patients with X chromosome abnormalities, 12 had mental retardation. All of the six (100%) with a small ring X were educable (EMI) or trainable mentally impaired (TMI) with more severe delay than expected in UTS. Among the 184 with other X abnormalities, only 6 had similar delays (2 from postnatal catastrophes), for a frequency of 3.3% mental retardation among those without a small ring X; only 2.2% of these had unexplained mental retardation. Polymerase chain reaction studies showed no Y-derived material in the 2 patients who were evaluated, and in situ hybridization confirmed X origin of the ring in the 6 subjects who were evaluated. We describe the phenotype of the 6 individuals with a small ring X, and an additional 2 patients with a small ring X who were identified outside the survey. The subjects with a small ring X comprised a clinically distinct subgroup which had EMI/TMI and shorter stature than expected in UTS. Seizures and a head circumference <10th centile were observed in half of the patients with a small ring X, and strabismus, epicanthus, and single palmar creases were present in more than half. A “triangular” face in childhood, pigmentary dysplasia, sacral dimple, and heart defects were also common. Neck webbing appeared to be less frequent than in 45, X. We hypothesize that the high risk of mental retardation in this form of the UTS results from lack of lyonization of the ring X due to loss of the X inactivation center. Excluding those with a small ring X, mental retardation is not significantly increased in patients with UTS. © 1992 Wiley-Liss, Inc.     

Mild thyroid abnormalities and recurrent spontaneous abortion: diagnostic and therapeutical approach

PROBLEM: The aim of this study is to evaluate the role of mild thyroid abnormalities in recurrent spontaneous abortion, and to assess the effects of two different therapeutical protocols. METHOD: A prospective study in the population of recurrent aborters with mild thyroid abnormalities, evaluating the obstetric outcome in 42 patients. Sixteen thyroid autoantibodies positive patients were treated with thyroid replacement therapy, while 11 patients received intravenous immunoglobulins (IVIG). Fifteen patients, characterized by negative antithyroid antibodies, and having underlying thyroid pathology, were treated with thyroid replacement therapy. RESULTS: Among patients with thyroid antibodies, 6 out of the 11 pregnancies (54.5%) treated with IVIG ended in live birth. In the thyroid supplementation group, 13 out of 16 pregnancies (81.2%) ended in live birth. Only one pregnancy loss occurred among patients with a mild underlying thyroid pathology treated with thyroid replacement therapy. CONCLUSIONS: Mild thyroid abnormalities are associated with an increased rate of miscarriage. This poor obstetrical prognosis seems to be related to an impaired thyroid adaptation to pregnancy. Thyroid replacement therapy appears to be more effective than IVIG in preventing a new miscarriage.     

Deleterious effects of low-dose oestrogen theraphy on coronary status in patients with prostatic cancer

The effects of oestrogen therapy and of orchidectomy on coronarystauts, as reflected by exercise ECG-testing before and afteryear of tretment, were assessed in a randomized study of patients(N=100) prostatic cancer. Oestrogen was given as polyestradiolphosphate 80 mg i.m. per month in combination with 150 µgor in pre-traetment exercise test results Twelve months afterstart of therapy the oestrogen group showed a significantlygreater depression of the ST-segment during maximal exercisein leads CH₂ (P<0.0005) and CH⁵)P<0.01) compared withthe pre-treatment depression. Twenty-five per cent (N=13) ofthe patients in the oestrogen group suffered cardiovascularcomplications during the yera the of therapy, whereas no suchcomplications were observed in the orchidectomy group. However,even the patients in the oestrogen group who had not sufferedcardiovascular complications had significantly greater depressionsof the ST-segment during exercise both in lead CH₂ (P<0.0005)and in CH₅ (P<0.05). There was no significant change in theST-segment level in the orchidectomy group twelve months aftersurgery. In summary, we found of an induction of myocardialishaemia during treatment with exogenous oestrogens at low dosagein patients with prostatic. This deleterious effect of oestrogenon the coronary status argues against oestrogen therapy, sinceoedtrogen has not been shown to be more beneficial than orhidectomyagainst prostatic carcinoma.     

Immunologic defects as possible causes of therapeutic failures in children with transposition of the great arteries

Summary Recurrent and severe infections and absence of thymic shadow in X-ray examination were observed in children with the transposition of the great arteries (TGA). Among 45 children (29 boys and 16 girls) with TGA whose age ranged from 3 days to 16 years and who were hospitalized during 1 year, infectious diarrhea was observed in 77.7% cases, urinary tract infections in 44.5%, respiratory tract infections in 42.2%, sepsis in 17.5%, and meningitis in 8.8%. Nine of the children died, sepsis was a cause of death in seven children, and there were postsurgical complications in two children. Immunologic abnormalities in children with TGA included a decreased level of T-lymphocytes and T_29° subpopulation, impaired mitogen-induced lymphoproliferation in vitro, and increased nitro blue tetrazolium (NBT) reduction activity of monocytes. Impaired parameters of cellular immunity correlated with worst clinical status. No disorders of humoral immunity were observed. These observations may be important for forming opinion about proper therapy and the cause of death in children with TGA.All results have been included in T. Marek-Szydowska's doctoral dissertation and were communicated at the 65th Annual Meeting of Deutsche Gesellschaft für Rechtsmedizin, St. Gallen, Switzerland, Sept. 9–13, 1986     

微型心电监视仪的研制

本文介绍我们近年研制成功的一种全新的微型化的心电监视仪。该仪器集主机，显示器，电极导联于一体，适合医务人员随身携带，用于需要快速、简易、准确地获取人体心电图形与心率数据的场合。     

Discontinuation of Phenytoin, Carbamazepine, and Valproate in Patients with Active Epilepsy

The effects of discontinuing individual antiepileptic drugs (AEDs) in patients with active epilepsy who are receiving combination therapy have not been studied systematically. We report a double-blind, prospective study of discontinuation of phenytoin (PHT), carbamazepine (CBZ), and valproate (VPA) in 70 patients with chronic active epilepsy. Each drug discontinuation was randomized to one of two relatively fast rates of reduction, and a control group of 25 patients continued with stable therapy. Patients who had CBZ removed had a significant increase in seizures that was maintained for 4 weeks after the end of drug reduction, and 10 of these 23 patients had to restart therapy with CBZ. There was no significant change in seizure numbers in the other groups. Two patients discontinued from VPA had to restart the drug; none had to restart PHT. The optimal rates of reduction of CBZ remain uncertain. There was no evidence for a clinically or temporally distinct burst of "discontinuation seizures" in any group. Any marked increase in seizures always resolved on reintroduction of the discontinued drug.     

QTcd、JTcd在运动试验中的意义

为了解QTcd、JTcd在心电图活动平板运动试验结果判断中的价值 ,对 10 0例活动平板运动试验阳性者及 80例阴性者运动前后的心电图QTcd、JTcd进行对比观察。结果表明 :运动前两组QTcd、JTcd差异均无显著性 ( P〉0 .0 5 ) ;运动后 2min运动试验阳性组与阴性组比较 ,QTcd、JTcd差异有高度显著性 (P <0 .0 1) ;阳性组运动试验后 2minQTcd、JTcd均较运动前显著延长 ( P <0 .0 1) ;阴性组运动后 2minQTcd、JTcd与运动前比较差异无显著性 ( P >0 .0 5 )。认为运动试验后QTcd、JTcd延长可作为判断运动试验结果的指标。     

Meiotic abnormalities and spermatogenic parameters in severe oligoasthenozoospermia

The incidence of meiotic abnormalities and their relationship with different spermatogenic parameters was assessed in 103 male patients with presumably idiopathic severe oligoasthenozoospermia (motile sperm concentration < or = 1.5 x 10(6)/ml). Meiosis on testicular biopsies was independently evaluated by two observers. Meiotic patterns included normal meiosis and two meiotic abnormalities, i.e. severe arrest and synaptic anomalies. A normal pattern was found in 64 (62.1%), severe arrest in 21 (20.4%) and synaptic anomalies in 18 (17.5%). The overall rate of meiotic abnormalities was 37.9%. Most (66.7%) meiotic abnormalities occurred in patients with a sperm concentration < or = 1 x 10(6)/ml. In this group, total meiotic abnormalities were found in 57.8% of the patients; of these, 26.7% had synaptic anomalies. When the sperm concentration was < or = 0.5 x 10(6)/ml, synaptic anomalies were detected in 40% of the patients. In patients with increased follicle stimulating hormone (FSH) concentrations, total meiotic abnormalities occurred in 54.8% (synaptic anomalies in 22.6%). There were statistically significant differences among the three meiotic patterns in relation to sperm concentration (P < 0.001) and serum FSH concentration (P < 0.05). In the multivariate analysis, sperm concentration < or = 1 x 10(6)/ml and/or FSH concentration > 10 IU/l were the only predictors of meiotic abnormalities.