Time-frequency analysis of heart murmurs. Part II: Optimisation of time-frequency representations and performance evaluation

The basic parameters of the spectrogram, the Choi-Williams, and the Bessel distributions are adjusted to provide the best time-frequency representations (TFRs) of the simulated murmur signals of mitral stenosis, mitral regurgitation, aortic stenosis, aortic regurgitation, and of two musical murmurs. The initial adjustment of the parameters of each TFR technique is performed by computing and minimising the relative averaged absolute error between the frequency contours at −3dB and −10dB of each TFR of the simulated murmurs and those of the theoretical distribution of the same signals. The results show that the spectrogram generally provides very good to excellent performance in representing the TFRs of stenotic and regurgitant murmurs. Improvements provided by the Choi-Williams and the Bessel distributions are minor but not systematic for the two signal-to-noise ratios tested (0 and 30 dB) and for the two frequency contours estimated. The Bessel and the Choi-Williams distributions provide the best performance for the musical murmurs. The study shows that although a single technique cannot be optimal for all six murmurs, the spectrogram using a Hamming window of 30 ms is an acceptable compromise to detect the six simutated heart murmurs.     

大鼠肝抑素样提取物的生物效应初探

从大鼠肝分离出小分子蛋白质,注入肝大部切除的大鼠体内。术后24h制备肝细胞悬液及骨髓细胞悬液,用流式细胞计测定细胞DNA含量。结果:①实验组大鼠每克体重注入肝提取物10～300μg,一致呈现4n肝细胞DNA复制受阻于G_1期,各类肝细胞数与正常大鼠的相似;②对照组大鼠,4n肝细胞由正常的68.1％降至30.9％,8n肝细胞由6.3％骤增至25.3％,并出现16.8％的4n～8n间8期肝细胞;③两组大鼠的骨髓细胞DNA含量均无变化。表明肝提取物中含有肝抑素样物质,它特异性地使再生肝的4n肝细胞增殖周期阻滞于G_1期及S早期。     

Rectus muscle flap for repair of refractory bladder fistula following renal transplantation: a case report

We report a case of refractory bladder fistula in a diabetic renal allograft recipient that recurred shortly after conventional operative repair without any detectable external cause. After reoperation and use of a vascularized rectus muscle flap the fistula closed and the patient has retained excellent graft function. It is suggested that this technique should be considered as the primary repair modality for bladder fistulas in diabetic recipients, when wound healing is impaired seriously as a consequence of the combined effects of diabetic microangiopathy and steroid therapy.     

A method of portalizing the venous blood flow of the left adrenal gland

The authors, having studied the long-term results of the operation of creating the renoportal venous anastomoses in patients with severe and malignant course of arterial hypertension, revealed anastomotic thrombosis in presence of hypotensive effect. Developed in the experiment and employed in 7 patients was the technique of dosaged narrowing the central left adrenal vein with the aim of achieving its thrombosis, inclusion of the collateral routes of the left adrenal blood outflow into the system of the portal vein and inactivation of aldosterone in the liver.     

Injury of the rotator cuff. I. Morphological and patho-physiological basis

Authors summarize the basic features of the functional anatomy and pathogenesis of the rotator cuff tears, essential for clinical practice. On the basis of literary data and own experiences a new classification of the rotator cuff tears was elaborated that can be reliably used in operative indications.     

Surgical treatment of myasthenia gravis in children

Thymectomy was included in the complex of therapeutic measures in the management of generalized myasthenia in 41 children. Much attention was given to preoperative management in which plasmapheresis was applied along with the traditional methods. As a result, maximum compensation of the myasthenic disorders was achieved and spontaneous respiration was restored in 9 patients who were given artificial ventilation of the lungs before the operation. The authors describe the techniques of thymectomy and the changes found in the thymus during histological study. No complications occurred. All of the children were discharged from the clinic in an improved condition. The late-term results were studied in 38 children in follow-up periods of 6 months to 4 years. Marked stable improvement was recorded in 31 (77.5%) patients.     

Biochemical markers of compliance in the Physicians' Health Study

The Physicians' Health Study is a randomized, double-blind, placebo-controlled trial using a 2 x 2 factorial design to test the effects of low-dose aspirin on risk of cardiovascular disease and beta-carotene supplementation on the incidence of cancer. To evaluate self-reported compliance with assigned treatment, we measured serum thromboxane B2, which is decreased after aspirin use, and plasma beta-carotene in samples of study participants drawn from three geographic locations in three different time periods. Thromboxane B2 levels were markedly lower in those assigned to aspirin (median = 63.5 pg/mL) than in those given aspirin placebo (median = 3,600 pg/mL, P less than .0001). Similarly, those assigned to beta-carotene had significantly higher levels (median = 1,176 ng/mL) than those given placebo (median = 306 ng/mL, P less than .0001). In addition, there was a highly significant positive correlation between levels of these biochemical markers and the self-reports of compliance (r = 0.65 for thromboxane B2 and r = 0.69 for beta-carotene, P less than .0001). These findings support the validity of the self-reported compliance in the Physicians' Health Study.     

Acetabular protrusion in thalassemia. A report of four cases

Four female patients with thalassemia intermedia developed secondary acetabular protrusion. These cases could be the first reported cases of nontraumatic acetabular protrusion in patients with thalassemia. The rarified pelvic bone may be due to medullary hyperplasia, iron overload, or disordered calcium metabolism in conjunction with osteomalacia. The fact that currently patients with beta-thalassemia have a longer life expectancy may explain the recent observation of this entity, which should become more familiar to orthopedic surgeons who treat thalassemia patients in the future.     

Mutational analysis of familial and sporadic hyperekplexia

Hyperekplexia is a rare, autosomal dominant neurological disorder characterized by hypertonia, especially in infancy, and by an exaggerated startle response. This disorder is caused by mutations in the ?1 subunit of the inhibitory glycine receptor (GLRA1). We previously reported two GLRA1 point mutations detected in 4 unrelated hyperekplexia families; both mutations were at nucleotide 1192 and resulted in the replacement of Arg²⁷¹ by a glutamine (R271Q) in one case and a leucine (R271L) in the other. Here, 5 additional hyperekplexia families are shown to have the most common G-to-A transition mutation at nucleotide 1192. Haplotype analysis using polymorphisms within and close to the GLRA1 locus suggests that this mutation has arisen at least twice (and possibly four times). In 2 additional families, a third mutation is also presented that changes a tyrosine at amino acid 279 to a cysteine (Y279C). Five patients with atypical clinical features and equivocal or absent family history of hyperekplexia and 1 patient with a classical presentation but no family history are presented in whom a mutation in the GLRA1 gene was not detected. Thus, only clinically typical hyperekplexia appears to be consistently associated with GLRA1 mutations, and these affect a specific extracellular domain of the protein.