Familial Deficiency of Apolipoproteins A-I and C-III and Precocious Coronary-Artery Disease

We studied two sisters 29 and 31 years old who had skin and tendon xanthomas, corneal clouding, and severe coronary atherosclerosis. Histologic examination showed collections of lipid-laden histiocytes in the skin. The patients' plasma cholesterol concentrations were 177 and 135 mg per deciliter (4.58 and 3.49 mmol per liter). Levels of high-density-lipoprotein cholesterol were 4 and 7 mg per deciliter (0.1 and 0.2 mmol per liter). Only traces of apolipoprotein A-I were detected in whole plasma. The plasma density fraction from 1.06 to 1.21 g per milliliter contained no high-density lipoprotein on high-pressure liquid chromatography, no apolipoprotein A-I on sodium dodecyl sulfate electrophoresis, and only traces of apolipoprotein A-I on radioimmunoassay. Apolipoprotein C-III was also not detectable. The activity of lecithin-cholesterol acyltransferase was 40 per cent of normal. The half-life of infused normal high-density lipoprotein was three days (normal, 5.8 days). The parents and children of these two patients had low levels of high-density-lipoprotein cholesterol and apolipoprotein A-I. These cases support the hypothesis that low concentrations of high-density lipoprotein promote atherosclerosis. (N Engl J Med. 1982; 306:1513–9.) THE inverse relation between coronary-artery disease and the concentration of high-density-lipoprotein (HDL) cholesterol in blood suggests that this lipoprotein is an important factor in the pathogenesis of atherosclerosis. 1 2 3 Low levels of HDL cholesterol have been associated with an increased frequency of coronary heart disease, even at an HDL level no less than 50 per cent of normal. Yet in Tangier disease, an inherited disorder of cholesterol metabolism in which HDL cholesterol is about 8 per cent of normal, the frequency of atherosclerosis is not increased. 4 We have studied two sisters with a severe deficiency in HDL who had severe and . . 

Neural Resolution of Formant Frequencies in the Primary Auditory Cortex of Rats

Pulse-resonance sounds play an important role in animal communication and auditory object recognition, yet very little is known about the cortical representation of this class of sounds. In this study we shine light on one simple aspect: how well does the firing rate of cortical neurons resolve resonant ("formant") frequencies of vowel-like pulse-resonance sounds. We recorded neural responses in the primary auditory cortex (A1) of anesthetized rats to two-formant pulse-resonance sounds, and estimated their formant resolving power using a statistical kernel smoothing method which takes into account the natural variability of cortical responses. While formant-tuning functions were diverse in structure across different penetrations, most were sensitive to changes in formant frequency, with a frequency resolution comparable to that reported for rat cochlear filters

Microdialysis Combined with Proteomics for Protein Identification in Breast Tumor Microenvironment In Vivo

Tumor microenvironment constitutes a reservoir for proteins released from tumor cells and the host, which can contribute significantly to tumor growth and invasion. This study aims to apply a method of combining in vivo microdialysis and proteomics to identify proteins in mammary tumor interstitial fluids, a major component of tumor microenvironment. In vivo microdialysis was performed in polyomavirus middle T antigen (PyVmT) transgenic mouse mammary tumors and age-matched control wild-type mammary glands. Over four hundred proteins were identified from the microdialysis perfusates, using the Multidimensional Protein Identification Technology. Osteopontin (OPN) is one of the proteins overexpressed in breast tumor perfusates, as confirmed with immunoassays. OPN was also found to be present in tumor-associated stroma in both PyVmT and human breast tumors, using immunohistochemistry. Specifically, fibroblasts were further shown to express OPN at both mRNA and protein levels. In vitro assays showed that OPN can stimulate PyVmT breast carcinoma cell proliferation and migration. Finally, the expression of OPN was significantly higher in the peripheral blood of mice bearing breast tumors, compared to wild-type mice. Overall, microdialysis combined with proteomics is a unique technique for identifying proteins in a tumor microenvironment in vivo. Mammary fibroblasts can secrete OPN, and its overexpression in mammary tumor microenvironment may contribute significantly to mammary tumor progression