Relationship between low-frequency electromagnetic field and computer vision syndrome.

OBJECTIVE: This study aimed to determine the prevalence of computer vision syndrome (CVS) among secretaries working in different departments of a university hospital in Turkey and its relationship with low-frequency electromagnetic field (LF-EMF) exposure. SUBJECTS AND METHODS: This cross-sectional study included 143 secretaries working in different departments of the hospital. Besides eye examinations, CVS Syndrome Questionnaire (CVS-Q) Scale and Ocular Surface Disease Index Scale (OSDI) were applied to the participants. LF-EMF of the work environment were measured with a 6010 Gauss/Teslameter device and the light intensity with an LX-1102 Device. RESULTS: The mean age of participants was 39.6 years, with a male-to-female ratio of 25.2% to 74.8%. CVS-Q scale revealed 83.9% of computer vision syndrome among participants. A weak positive correlation was found between CVS-Q and LF-EMF, while a moderately strong, negative correlation was found between LF-EMF and Schirmer test of both eyes. The work environment LF-EMF values were significantly higher among the participants diagnosed with CVS (p<0.05). The risk of CVS was found to increase 3.27 times when the ambient LF-EMF was >1,725 µT and an increase of 0.004 units in the CVS-Q score was calculated for each one-unit increase in the LF-EMF of the environment. CONCLUSIONS: A relationship between CVS, dry eye and EMF was observed among people exposed to LF-EMF. Regular measurement of EMF in work environments, and developing protective behaviours (work-break intervals, 20-20-20 rule, etc.) can be recommended.

Hepatitis B virus nucleic acids circulating in the blood: distinct patterns in HBs carriers with hepatocellular carcinoma.

Circulating nucleic acids in serum and plasma are common in a variety of disease conditions. Here, we focus (i) on our approach for the detection of various hepatitis B virus (HBV)-related nucleic acids in liver tissue and in serum, (ii) on the progression of the chronic HBV infection, (iii) on the relation of HBV-specific nucleic acids circulating in the blood of patients with hepatocellular carcinoma, and in general (iv) on the diagnostic potential of circulating HBV nucleic acids.

Flux of amino acids and energy substrates across the leg in weight-stable HIV-infected patients with acute opportunistic infections: indication of a slow protein wasting process.

Increased whole-body proteolysis with muscle protein net degradation has been suggested as one of the causes of weight loss in patients infected with human immunodeficiency virus (HIV). We studied the exchange rates of amino acids and energy substrates across the lower extremity in 16 HIV patients and 16 age-matched controls with similar body cell mass. The patients had either opportunistic infections or chronic diarrhea but no signs of clinical malnutrition. The following findings were obtained in the HIV patients: an augmented peripheral net release of arginine and lysine; an increase in both the negative arterial-venous difference and the efflux of the nitrogen contained in nonmetabolized amino acids; diminished export of 3-methylhistidine; lowered plasma and erythrocyte amino acid concentrations; reduced output of glycerol and furthermore; and neither a net release nor a net uptake of free fatty acids. The findings concerning nitrogen metabolism support the hypothesis that, in the presence of a reduction in protein breakdown, peripheral protein synthesis is severely depressed, making a slow protein wasting process likely to occur. The balances of glycerol and free fatty acids are due not only to the leg tissues but perhaps also in part to increased net retention of these substrates by skeletal muscle.

Effect of carnitine on muscular glutamate uptake and intramuscular glutathione in malignant diseases.

Abnormally low intramuscular glutamate and glutathione (GSH) levels and/or a decreased muscular uptake of glutamate by the skeletal muscle tissue have previously been found in malignant diseases and simian immunodeficiency virus (SIV) infection and may contribute to the development of cachexia. We tested the hypothesis that an impaired mitochondrial energy metabolism may compromise the Na+-dependent glutamate transport. A randomized double-blind clinical trial was designed to study the effects of L-carnitine, i.e. an agent known to enhance mitochondrial integrity and function, on the glutamate transport and plasma glutamate level of cancer patients. The effect of carnitine on the intramuscular glutamate and GSH levels was examined in complementary experiments with tumour-bearing mice. In the mice, L-carnitine treatment ameliorated indeed the tumour-induced decrease in muscular glutamate and GSH levels and the increase in plasma glutamate levels. The carnitine-treated group in the randomized clinical study showed also a significant decrease in the plasma glutamate levels but only a moderate and statistically not significant increase in the relative glutamate uptake in the lower extremities. Further studies may be warranted to determine the effect of L-carnitine on the intramuscular GSH levels in cancer patients.

Presence of plasma endotoxin is correlated with tumour necrosis factor receptor levels and disease activity in alcoholic cirrhosis.

Cytokines and plasma endotoxin were measured in a consecutive series of patients with alcoholic cirrhosis (AC). Endotoxaemia was found to be strongly correlated to increased plasma levels of functionally active tumour necrosis factor (TNF) receptors -p55 and -p75, TNF-alpha and the Child-Pugh stage of the disease. Our data support the hypothesis of the pathogenic role of lipopolysaccharide in hepatocellular damage of patients with AC.

Linkage between postabsorptive amino acid release and glutamate uptake in skeletal muscle tissue of healthy young subjects, cancer patients, and the elderly.

Several diseases of varying etiology that are commonly associated with the loss of skeletal muscle mass were found to be associated with a decrease in muscular glutamate and glutathione levels and in glutamate uptake in the postabsorptive state. In view of the Na+ dependency and insulin responsiveness of glutamate transport we studied the postabsorptive glutamate exchange in more detail. Our study demonstrates a linkage between glutamate uptake and the export of other amino acids, suggesting that protein catabolism and the resulting coexport of amino acids plus Na+ substitute for insulin as a driving force for the Na+ gradient in the postabsorptive state. The regression function of the correlation between relative glutamate exchange and cumulative amino acid exchange in cancer patients was lower than that in non-tumor-bearing subjects, suggesting that cancer patients must release more amino acids to achieve the same glutamate uptake. In addition, cancer patients had a lower average cumulative amino acid exchange rate than non-tumor-bearing subjects, suggesting that the abnormally low relative glutamate exchange capacity of cancer patients results mainly from inadequate postabsorptive protein catabolism in the skeletal muscle tissue. Both cancer patients and non-tumor-bearing elderly subjects had higher arterial glutamate levels and alanine release than young subjects, indicative of a substantial glycolytic activity in the skeletal muscle. However, elderly non-tumor-bearing subjects showed, in contrast to cancer patients, in the postabsorptive state a stronger cumulative amino acid release and postabsorptive glutamate uptake than healthy young subjects. These changes are discussed in view of the age-related loss of skeletal muscle mass.

Substrate balances across colonic carcinomas in humans.

To investigate the utilization of nutrients by malignant tumors in humans, the balances of energy-yielding substrates and amino acids across colonic carcinomas were assessed in 17 patients during surgery. Blood samples were taken from an artery and the main tumor-draining vein, which was also used for determining tumor blood flow (direct venous outflow technique). Additionally, the substrate exchange by peripheral tissues was studied (femoral arteriovenous differences, venous occlusion plethysmography). Mean blood flow was greater in the carcinomas than in the leg tissues (43.2 versus 2.5 ml/100 ml/min; P < 0.001). There was a negative correlation between tumor blood flow and tumor weight (r = -0.87; P < 0.001). Glucose net uptake and lactate release by the malignancies exceeded the peripheral exchange rates 30- and 43-fold, respectively (mean values different at P < 0.001). The molar ratio of lactate output to glucose consumption was 0.78 in the tumors and 0.48 in the leg tissues (P < 0.05). Regarding free fatty acid and ketone body balances, no significant tumor-periphery differences were noted. The carcinomas utilized branched chain amino acids and serine, while alanine and, in particular, ammonia were released in large amounts. Net glutamine retention was not consistently observed. It is concluded that the energy metabolism of human colonic carcinomas relies predominantly on glucose, with fat-derived calories making no appreciable contribution. The impaired nutritive perfusion of malignant tumors appears to favor glycolysis and to limit both glucose oxidation and glutaminolysis. The present study has shown that the procedure chosen for the assessment of trans-tumor substrate flux rates is a workable and valid model for analyzing metabolic balances across human colonic cancers in vivo.

[Epithelial growth factor receptors (EGF-R) and DNA flow cytometry in addition to lymph node and hormone receptor status as prognostic factors in primary breast cancer]. / Epitheliale Wachstumsfaktor-Rezeptoren (EGF-R) und DNA-Flowzytometrie neben Lymphknoten- und Hormonrezeptorstatus als Prognosefaktoren beim primären Mammakarzinom.

The presence of receptors for epidermal growth factor (EGF-R), the percentage of cells in S-phase and DNA-ploidy measured by flow-cytometry are new prognostic factors in breast cancer. In order to investigate the relationship between EGF-R, S-Phase/DNA-ploidy and clinical data, we measured these parameters in 68 tumors from patients with operable breast cancer. 11 Patients had positive EGF-R's (specific binding greater than 10 fmol/mg membrane-protein) and 37 patients had a positive S-Phase (more than 5% of cells in S-Phase). 10 of 44 carcinomas of ductal type were EGF-R positive, while only 1 of 18 lobular-type tumor displayed positive EGF-R's. We found significant inverse correlations between EGF-R's and estrogen receptors (p less than 0.00001) and between EGF-R's and age (p less than 0.0001): EGF-R positive tumors were found more often in young patients and in patients with estrogen-receptor-negative tumors. The EGF-R's and flow-cytometric data did not correlate with tumor size and/or nodal status. There was no correlation between EGF-R and S-Phase/DNA-ploidy in the breast cancer specimens suggesting that these two prognostic parameters are independent from each other.