Optimization of the assay for sialic acid determination in low density lipoprotein

Sialic acid level in blood plasma and circulating glycoproteins is considered to be a marker for a number of pathologic conditions, including atherosclerosis, cancer, etc. The precise measurement of sialic acid level is an important laboratory procedure to allow correct interpretation of results. Colorimetric methods commonly used for the measurement of sialic acid are not highly specific, as interfering substances may alter the results. Among these, malondialdehyde and other aldehydes play the decisive role. In the circulation, aldehydes are commonly produced during lipid peroxidation in the lipid core of lipoprotein particles, especially low density lipoprotein (LDL). To establish the impairment to the sialic acid determination in LDL introduced by interfering substances, the optimized assay based on Warren's traditional method was developed and tested in 606 LDL samples. The optimization implies the comparison of color developed using the standard Warren procedure with that due to contaminating agents, mainly thiobarbituric acid-reactive substances (TBARS). In LDL stored at 4 degreesC, the estimates obtained by the modified procedure were 41.5% or 30.1 nmol/mg lower, on average, compared to the standard procedure (n = 45, P < 0.0001). Even in LDL stored at -70 degreesC, sialic acid estimates obtained by the modified procedure were 6.6% or 3.6 nmol/mg lower, on average, compared to the standard measurement (n = 561, P < 0.005). Thus, the modified procedure avoids significant distortion of the measurement induced by the presence of interfering agents.     

New methods of treatment for cerebral aneurysms

We present a case of a 25-year-old male with a large secondum atrial septal defect (ASD) associated with a coronary artery fistula (CAF) between the right coronary artery and the right atrium. The ASD was diagnosed preoperatively by transesophageal echocardio-graphy (TEE). The fistula was found at surgery. The ASD and fistula were closed successfully without any complication. The case highlights the common presenting features of the two conditions as well as the low sensitivity of pre-operative TEE in diagnosing CAF in the setting of an ASD.     

Luminescence and structure of the protonated forms of meso-tetraarylporphyrins in solution

A distillate of light alkylate naphtha (CAS number 64741-66-8; LAN distillate) was administered via inhalation, 6 h/d, 7 d/wk to 4 groups of Sprague-Dawley rats (10/sex/dose) at target concentrations of 0 (filtered air control), 5, 12.5, or 25 g/m3 with the highest dose exceeding 60% of the lower explosive limit of LAND. Exposure began 2 wk prior to mating and continued throughout gestation until postnatal d 4 for females or for 8 consecutive weeks for males. No apparent clinical signs indicative of systemic toxicity were observed in the F0 and F1 animals of either sex. Inhalation exposure to LAND up to and including the 25 g/m3 dose level had no effect on parental food consumption, body weights, absolute and relative organ weights, and reproductive indices. All groups had comparable delivery data and a fertility index > or 80%. Pups in all groups showed comparable birth weights, weight gain, a viability index (postnatal d 4) for all groups of > or = 97%, and no histopathological changes. In the dams, there were no significant differences in the mean numbers of corpora lutea, implantation sites, and resorptions recorded at necropsy. In the males, the only remarkable findings at necropsy were a small right epididymis and testis seen in one mid-dose male and an abscess on the right epididymis of a high-dose male. In both cases, the dams that had been bred to these males produced normal litters. There were no test material-related microscopic changes observed in the testes and epididymis of the F0 male rats or ovaries of the F0 female rats exposed to LAND. Under the conditions of this experiment, the no-observed-adverse-effect level (NOAEL) for LAND via inhalation in rats is established at greater than 24.7 g/m3 (analytical concentration).     

Effects of corticosteroid and nonsteroid antiinflammatory drugs on corneal transparency after photorefraction keratectomy

The paper reports 20-year follow-up results (from 1976-1977 to 1996-1997) of 175 patients with drug addiction that began at the young age. The patients with opiate addiction prevailed. Structural-dynamic alterations of the main clinic symptom complexes, the validity of the factors that are essential for the reduction of pathological drive are analyzed. There was a tendency to progressive decrease of narcotics administration as the severity of somatic pathology increased. Episodes of narcotics administration were permanent by the end of the second decade of the disease in less than 20% of the patients from the primary cohort; alcohol and psychotropic drug (hypnotics, tranquilizers) dependence has developed in about 1/3 of the patients. The most influence on the regress of pathologic drive had the factors related with both the duration of the isolation from narcotics and the development of schizophrenic process; therapeutic regress was observed much rarer. High lethality of the patients with drug addiction was found: more than 46% during 20 years of the disease.