Characterization of a precipitating antigen detected in the serum of patients with viral hepatitis

During a search for the aetiological agent of non-A non-B hepatitis, a precipitating antigen was detected in the sera of some patients during the acute phase of their illness. The antigen was detected by agar gel diffusion using antibody from convalescent sera obtained from patients with non-A non-B hepatitis, and from haemophiliac sera. The antigen was usually detected early in the patient's illness, disappearing as liver function tests returned to normal. In some patients specific antibody appeared during the convalescent phase of the disease. The antigen does not appear to be specific for non-A non-B hepatitis, as it could be detected with similar frequency in patients with hepatitis A or hepatitis B and some patients with other liver disorders. Biochemical and biophysical studies suggest that the antigen is probably an abnormal lipoprotein produced as a result of acute liver damage.     

The significance of angiogenesis in malignant pheochromocytomas

The purpose of this study was to investigate tumor angiogenesis in a series of benign and malignant pheochromocytomas and to determine whether there is a correlation between angiogenesis and the presence of distant metastases. In this study, the CD31 monoclonal antibody was selected to measure intratumoral microvessel density. Nineteen patients with malignant pheochromocytomas and nineteen patients with benign pheochromocytomas who underwent operation were studied. In order to quantify intratumoral microvessel density, the total number of pixels of CD31-positive reactivity was assessed and expressed as a percentage of the total tissue area in the analyzed field. Analysis of variance revealed a statistically significant correlation between malignancy and intratumoral microvessel density (p=0.0009). Although there was a considerable variability in the intratumoral microvessel density from tumor to tumor within both the benign and the malignant group, a percentage of more than 28.5% anti-CD31 stained area was found only in malignant tumors. In conclusion, this study shows that the mean intratumoral microvessel density in malignant pheochromocytomas is increased approximately two-fold as compared with benign tumors. However, the clinical significance of this prognostic marker is rather weak, because only 4 of the 19 malignant pheochromocytomas had microvesel density higher than this threshold of 28.5%.     

Mevalonic acidemia: First case of Japan

Summary Mevalonic acidemia is a rare metabolic disorder due to mevalonate kinase deficiency which affects the biosynthesis of cholesterol and nonsterol isoprenes. We report the first case of Japan. The clinical course is characterized by intrauterine growth retardation, postnatal growth failure, intractable diarrhea, liver dysfunctions and death at three months of age. Dysmorphic features including triangular face, protrusion of forehead, hypertelorism, low set ears and micrognathism were noted. High mevalonic acid level was found by GC/MS.     

A 9.6 kilobase deletion in the low density lipoprotein receptor gene in Norwegian familial hypercholesterolemia subjects

Haplotype analysis of the low density lipoprotein receptor (LDLR) gene was performed in Norwegian subjects heterozygous for familial hypercholesterolemia (FH). Southern blot analysis of genomic DNA, using an exon 18 specific probe and the restriction enzyme NcoI, showed that two out of 57 unrelated FH subjects had an abnormal 3.6 kb band. Further analyses revealed that this abnormal band was due to a 9.6 kb deletion that included exons 16 and 17. The 5' deletion breakpoint was after 245 bp of intron 15, and the 3' deletion breakpoint was in exon 18 after nucleotide 3390 of cDNA. Thus, both the membrane-spanning and cytoplasmatic domains of the receptor had been deleted. A polymerase chain reaction (PCR) method was developed to identify this deletion among other Norwegian FH subjects. As a result of this screening one additional subject was found out of 124 subjects screened. Thus, three out of 181 (1.7%) unrelated Norwegian FH subject possessed this deletion. The deletion was found on the same haplotype in the three unrelated subjects, suggesting a common mutagenic event. The deletion is identical to a deletion (FH-Helsinki) that is very common among Finnish FH subjects. However, it is not yet known whether the mutations evolved separately in the two countries.     

Presence of autoantibodies to apolipoprotein A-1 in patients with acute coronary syndrome further links autoimmunity to cardiovascular disease

Anti-apolipoprotein A-1 (Apo A-1) autoantibodies were described in autoimmune disorders such as systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) and might be involved in the genesis of arterial and venous thrombotic events. To investigate the presence of these autoantibodies in patients with acute coronary syndrome (ACS) without other features of autoimmunity, we set up an enzyme-linked immunosorbent assay (ELISA) for anti-Apo A-1 antibodies. We used it to investigate their prevalence in ACS as compared to SLE and APS and correlated them to plasma Apo A-1 and serum amyloid A protein (SAA) concentrations. The prevalence of anti-Apo A-1 autoantibodies in the healthy control group was 1% (1/92), but was significantly higher in other groups: 21% (11/53) in ACS group (P=0.001), 13% (12/92) in SLE and/or APS group (P=0.005). Multiple linear regression revealed a significant correlation between plasma Apo A-1 (r=-0.72, P=0.013), plasma SAA concentration (r=0.76, P=0.0066) and anti-Apo A-1 IgG titre in ACS patients. The presence of anti-Apo A-1 autoantibodies in patients with ACS highlights an additional link between autoimmunity, inflammation and atherosclerosis.     

Plasma lipids and lipoproteins and essential hypertension

In recent years there have been many studies demonstrating a correlation between increased arterial blood pressure and altered lipid profiles, and there has been an especially positive correlation between high cholesterol levels and blood pressure. There are differences between the various reports that are important. In our study the lipid distribution in 105 hypertensive patients with mild or moderate arterial hypertension according to WHO criteria without clinically or ultrasonographically apparent atherosclerosis was compared to the lipid distribution in 65 age-matched healthy persons. On the epidemiological level a significant, positive association was found between LDL serum levels (P 0.001), Apo B serum levels (P 0.001), serum triglyceride levels (P 0.05) and VLDL serum levels (P 0.01) and arterial hypertension. However, in contrast to recent reports, no significant difference was found between total serum cholesterol levels in normotensives and hypertensives, and there was no difference in HDL serum levels. No evidence could be found for a significant increase in lipoprotein (a) serum levels in hypertensives.Abbreviations LDL low density lipoprotein - VLDL very low density lipoprotein - HDL high density lipoprotein - Apo B 100 apolipoprotein B 100 - Apo A I apolipoprotein A I Correspondence to: H. Vetter     

Analysis of Electromagnetic Exposure in Wireless Power Transfer System for Endoscopic Micro-robot

A wireless power transfer system for endoscopic micro-robot operating at 36 kHz is presented in this paper. The issue of patient＇ s health and safety regarding exposure to the electromagnetic field is addressed. The specific absorption rate and current density can be used to investigate the electromagnetic influences on the biological tissues surrounded by the wireless power launching coil. In view of this purpose, the limited close-ound solenoid electromagnetic model is built, the relationship between the electric intensity and the specific absorption rate and current density is deduced, and the simulation experiments are done. Experimental results show that the values of SAR and current density related to different tissue catalogs are all very small and do not exceed their own limits respectively when the resonance frequency of operation is 36 kHz.     

A simple method for computer quantification of stage REM eye movement potentials

We describe a simple method for computer quantification of eye movement (EM) potentials during REM sleep. This method can be applied by investigators using either period-amplitude (PA) or Fast Fourier Transform (FFT) spectral EEG analysis without special hardware or computer programming. It provides good correlations with visual ratings of EM in baseline sleep and after administration of GABAergic hypnotics. We present baseline data for both PA and FFT measures for 16 normal subjects, studied for 5 consecutive nights. Both visually rated and computer-measured EM density (EMD) showed high night-to-night correlations across baseline and drug nights and the computer measures detected the EMD suppression that is produced by GABAergic drugs. Measurement of EM in addition to stage REM provides biologically significant information and application of this simple computer method, which does not require pattern recognition algorithms or special hardware, could provide reliable data that can be compared across laboratories.     

Theoretical analysis of surface EMG in voluntary isometric contraction

Summary A new stochastic model of the surface EMG is suggested and the spectral density of the surface EMG is studied theoretically and experimentally to confirm the validity of this model.Theoretical results show that while the contraction level is not so high, the shape of the spectral density (distribution) does not change and its amplitude is directly proportional to the motor unit firing frequency and recruitment.To illustrate the theoretical results, experiments were carried out for rectus femoris and biceps brachii. The surface EMG was lead off by bipolar surface electrodes. And the spectral density of the surface EMG was calculated using FFT algorithm.From these experimental results, it was confirmed that our theoretical results were almost valid.     

Hepatitis C virus particles of different density in the blood of chronically infected immunocompetent and immunodeficient patients: Implications for virus clearance by antibody

The purpose of this study was to analyse the influence of the humoral immune response on the generation and clearance of hepatitis C virus (HCV) RNA containing particles in the blood of chronically infected patients. Blood samples were fractionated by sequential flotation ultracentrifugation and HCV RNA was recovered in three fractions: low density of < 1.063 g/ml, intermediate density of 1.063-1.21 g/ml, and high density of > 1.21 g/ml. Serum low-density lipoproteins co-fractionated with the low-density particles, and high-density lipoproteins co-fractionated with the intermediate-density particles. Immunoglobulins were found exclusively in the high-density fractions. In patients with congenital immunodeficiencies, with no or low serum antibodies to the virus, mean HCV RNA titres were equal in each fraction, at approximately 10(5) IU/ml. In antibody-positive, immunocompetent patients, however, virus titres in the low-density fraction and those in the high-density fraction were reduced or absent in most patients, suggesting that virus particles in these fractions are subject to antibody-mediated clearance. Particles of intermediate density were approximately equal in titre in both patient groups, suggesting that these particles are neither generated by, nor cleared, as a result of the humoral immune response. Immunoprecipitation experiments indicated that particles of intermediate density were not complexed with either high-density lipoprotein or immunoglobulins. Elucidation of the mechanisms by which these particles are generated and maintained in the blood may provide valuable insight into the mechanism of virus persistence.