Induction of Epstein-Barr virus in B-lymphoblastoid cells by human immunodeficiency virus type 1

Individuals infected with the human immunodeficiency virus (HIV), the etiologic agent of acquired immunodeficiency syndrome (AIDS), often show symptoms associated with reactivation of Epstein-Barr virus (EBV). In this study, we show that exposure of EBV-positive B lymphocytes to HIV-1 in vitro induced the EBV replicative cycle in these cells, as evidenced by an increased proportion of cells expressing EBV early antigens (EA) and capsid antigens (VCA). Reactivation of EBV by HIV-1 appeared to be virus-dose-dependent and required virus penetration and expression in B cells. Although HIV-1 RNA was detected by in situ hybridization in the majority of HIV-1-infected B lymphocytes, induction of EA and VCA was transient and limited to less than 20% of the cell population. The tumor-promoting phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and HIV-1 acted synergistically and had similar kinetics in inducing the expression of EBV. Direct reactivation of EBV by HIV-1 may contribute to the role of EBV as a factor in the genesis of AIDS-related conditions.

Studies of safe maximal daily dietary selenium intake in a seleniferous area in China. I. Selenium intake and tissue selenium levels of the inhabitants

Studies of marginal safe Se-intake have been carried out in a seleniferous section of China since 1985. Three areas with low, medium and high Se levels were selected for this study. The respective average daily Se-intake (mean +/- SE) was 70.5 +/- 4.8 micrograms, 194.7 +/- 22.9 micrograms and 1438.2 +/- 76.3 micrograms for males, and 62.0 +/- 3.6 micrograms, 198.1 +/- 23.8 micrograms and 1238.5 +/- 64.6 micrograms for females (average body weight: male 55 Kg, female 53 Kg). When the increasing rate of Se-intake was compared with the corresponding tissue-Se levels it was found that the whole blood Se-level reflected more closely the physiological range of Se-intake, while at higher Se-intakes it became less sensitive than the levels in hair, finger-nail and toe-nail, which were comparable to the sensitivity of urine. It is suggested that hair, finger- and toe-nail may all act as excretory organs when excess amounts of Se are ingested. Hair- and blood-Cd are somewhat higher in residents of the high Se area, but whether they have influenced human Se-metabolism at the high level of Se-intake is not yet known. Significant correlations on log-log plots were obtained between levels of daily Se-intake and whole blood r = 0.878), breast milk (r = 0.899) and 24-h-urine (r = 0.859). Highly significant correlations on log-log plots between levels of tissue were also obtained: urine Se--plasma Se (r = 0.968), whole blood Se--hair Se (r = 0.952), fingernail Se--toenail Se (r = 0.919), hair Se--fingernail Se (r = 0.914), hair Se--toenail Se (r = 0.891), whole blood Se--toenail Se (r = 0.849) and whole blood Se--fingernail Se (r = 0.836). The highly significant correlations found between the Se-intake and the tissue-Se level, and also between the Se levels of various tissues, could possibly conveniently be used to convert the known tissue-Se level to the corresponding Se-intake. Taken together with the wide range of Se-intakes and corresponding tissue-Se levels this would provide the necessary conditions for studying the marginal and maximal safe Se-intakes in humans.

The relationship between nutritional antioxidants and serum lipid peroxides in cancer patients

A new parameter, the ratio of lipid peroxide and vitamins E and C [LPO/(VE + VC)], has been proposed and used to reflect the balance between lipid peroxidation and antioxidation capability of cancer patients and of healthy human controls. The effects of vitamins E, C, and selenium on the serum LPO level in mice bearing Ascites Hepatomas (H22) have also been examined. The results showed that the average of LPO/(VE + VC) ratios in cancer patients (135 cases) was significantly higher than that of the normal controls (222 cases). The authors suggest that this ratio might be used as one of the parameters for early diagnosis and prognosis of diseases (including cancers) caused by free radicals and lipid peroxides. The results also showed that antioxidants - Se(Na2SeO3, 1mg/kg) or vitamin E (5mg/kg) could markedly decrease the level of serum LPO in the tumor-bearing animals. A smaller dose of VE (1mg/kg) and doses of Vc up to 300mg/kg showed no effect on the serum LPO levels when given separately. However, synergistic effects were observed when any 2 out of 3 or three nutrients were given together. Those with three nutrients significantly lowered the serum LPO level. These antioxidants also inhibited the proliferation of tumour cells.

Inhibition of inositol phospholipid synthesis and norepinephrine-stimulated hydrolysis in rat brain slices by excitatory amino acids

Inhibition by excitatory amino acid agonists of norepinephrine (NE)-stimulated phosphoinositide hydrolysis was studied in rat brain slices. Inhibition was not observed in cortical slices prelabeled with [3H]inositol but was observed when slices were incubated simultaneously with [3H]inositol, glutamate, and NE. Therefore, we hypothesized that glutamate inhibits the synthesis of inositol phospholipids available to the alpha 1-adrenergic receptor, thereby reducing NE-stimulated phosphoinositide hydrolysis. To test this hypothesis, the distribution of [3H]inositol in cortical slices was measured after 5, 10, 20, 40 and 60 min of incubation, with some slices being exposed to 200 microM NE, 1 mM glutamate, 1 mM N-methyl-D-aspartate (NMDA), 1 mM kainate, 1 mM quisqualate, or to NE in the presence of each of the excitatory amino acid agonists. Glutamate had little effect on the slice content of free [3H]inositol, but it severely reduced the synthesis of [3H]inositol phospholipids, in the presence or absence of NE. Glutamate also abolished NE-induced production of [3H]inositol monophosphate, [3H]inositol bisphosphate and [3H]inositol trisphosphate. Quisqualate mimicked the effects of glutamate, whereas NMDA and kainate caused less inhibition of the synthesis of [3H]inositol phospholipids and did not inhibit the response to NE. Glutamate produced similar inhibitory effects in slices from hippocampus and striatum. To test if the inhibitory effect of glutamate was the result of irreversible cell damage, cortical slices were incubated with 1 mM glutamate for 60 min prior to exposure to [3H]inositol and NE. Preincubation with glutamate did not reduce the synthesis of [3H]inositol phospholipids or inhibit NE-stimulated [3H]inositol monophosphate production. These results indicate that glutamate impairs the synthesis of inositol phospholipids. Each of the excitatory amino acid agonists, quisqualate, NMDA and kainate, inhibited [3H]inositol phospholipid synthesis, but only quisqualate affected [3H]inositol phospholipids available to the alpha 1-adrenergic receptor.

On techniques for detecting circumscribed masses in mammograms

A method for detecting one type of breast tumor, circumscribed masses, in mammograms is presented. It relies on a combination of criteria used by experts, including the shape, brightness contrast, and uniform density of tumor areas. The method uses modified median filtering to enhance mammogram images and template matching to detect the tumors. In the template matching step, suspicious areas are identified by thresholding the cross-correlation values, and a percentile method is used to determine a threshold for each film. In addition, two tests are used to remove false alarms from the resulting candidates. The results obtained by applying these techniques to a set of test images are described. They are judged encouraging.

Synthesis and physicochemical and immunological characterization of pneumococcus type 12F polysaccharide-diphtheria toxoid conjugates

A scheme for the synthesis and purification of conjugates, composed of the type 12F capsular polysaccharide of Streptococcus pneumoniae (Pn12F) and diphtheria toxoid, is described. The scheme is a modification of that described previously for the Vi capsular polysaccharide of Salmonella typhi, a linear homopolymer of N-acetylgalactoseaminouronic acid (S. C. Szu, A. L. Stone, J. D. Robbins, R. Schneerson, and J. B. Robbins, J. Exp. Med. 166:1510-1524, 1986). Pn12F is a branched-chain copolymer composed of a hexasaccharide repeating unit containing an aminouronic acid, N-acetylmannoseaminouronic acid (K. Leontein, B. Lindberg, and J. Lonngren, Can. J. Chem. 59:2081-2085, 1981). Sulfhydryl groups were introduced into Pn12F by forming an amide bond between cystamine and carboxyl groups of N-acetylmannoseaminouronic acid in the presence of a carbodiimide. The disulfide moiety of cystamine was reduced to form the cysteamine derivative of Pn12F which was, in turn, covalently bound to diphtheria toxoid by using the heterobifunctional linker N-succinimidyl-3-(2-pyridylthio)propionate. Unbound, high-molecular-weight Pn12F was removed from the conjugate by hydrophobic interaction chromatography through octyl Sepharose by using n-octyl-beta-D-glucopyranoside as the eluent. In young outbred mice, Pn12F did not elicit detectable serum antibodies. Pn12F-diphtheria toxoid, in contrast, elicited antibodies after two injections and had T-cell-dependent properties as evidenced by a response to priming and by its ability to elicit booster responses. This scheme seems applicable to the synthesis of conjugates with other capsular polysaccharides containing aminouronic acids. Clinical evaluation of Pn12F-diphtheria toxoid conjugates in healthy and in immunocompromised hosts is planned.

A pseudoinverse filter for limited-angle diffraction tomography involving objects with planar structure

A reconstruction technique for limited-angle diffraction tomography is described in which a special pseudoinverse filter is applied to the back-propagation. Using this approach, it is possible to reconstruct a ten-layered object with only 19 projections having angles ranging from -10 degrees to +10 degrees . It is concluded that the algorithm proposed here offers an efficient and computationally easy method for reconstructing an object with planar structure. Even when the number of layers is large and the range of incident angle is limited, the method will give good images.

Parallel Algorithms for Image Template Matching on Hypercube SIMD Computers

This correspondence presents several parallel algorithms for image template matching on an SIMD array processor with a hypercube interconnection network. For an N by N image and an M by M window, the time complexity is reduced from O(N2M2) for the serial algorithm to O(M2/K2 + M * log2 N/K + log2 N * log2 K) for the N2K2-PE system (1 ¿ K ¿ M), or to O(N2M2/L2) for the L2-PE system (L ¿ N). With efficient use of the inter-PE communication network, each PE requires only a small local memory, many unnecessary data transmissions are eliminated, and the time complexity is greatly reduced.

Calibration of optical fiber power meters: the effect of connectors

This paper addresses the question of accurate measurement of optical power at the wavelengths and power levels of interest to the telecommunications community. In particular, we examine the calibration of power meters that are destined for use in a field environment. Connectors and adapters are shown to skew the measurements, leading to errors attributable to reflections from the connector or to angular dependence of detector response. Calibration data are taken using two popular connector types: a biconic and an SMA type. The data are sufficient to illustrate the problem but definitive conclusions cannot be drawn regarding variability of performance with connector or connector type, because of the limited data.

The first stage in two-stage template matching

This paper formulates the problem encountered in the first stage of two-stage, binary template matching as a set of hypotheses to be tested, including a hypothesis of ``no object.'' Two new statistics R and G are proposed, based on a likelihood ratio, and are compared to the sum of absolute differences and a correlation measure by analytical approximations and Monte Carlo experiments. Statistical power and a measure of sensitivity to the true location of the object are the criteria. Parameters are the numbers of 1's in object and image, subtemplate size, and parameters reflecting intensity distortion between template and object. One of the proposed statistics R is much more computationally intensive than the other G. Although R is more powerful than G and the other statistics, G is generally more sensitive to the true object location. Statistic G is also more powerful than the sum of absolute differences and correlation. All statistics are robust to incomplete knowledge of distortion parameters. Experiments on Landsat images confirm the sensitivity of G and recommend it for application in the first stage.

Activation of the classical complement pathway by a polysaccharide from sugar cane

The effects of an immunostimulating polysaccharide, Bo, from sugar cane, on the complement system have been investigated. Bo, a glucan of about 10,000 mol wt, was found to activate complement in whole human and guinea pig serum in vitro by the classical pathway. Complement consumption was also demonstrated in guinea pigs upon intravenous injection. Specifically, C1 is activated, and C4 and C2, as well as C3, are consumed. The activation is prevented when Ca++ ions are chelated by ethyleneglycoltetraacetic acid, and when C1q is lacking. Hence, it does not rest on direct activation of C1s. Supplementation of C1q-deficient human serum with purified C1q restores the ability to be activated by Bo. The alternative pathway of complement is little if at all affected by the polysaccharide. The activation of C1 seems to be mediated by immune complex formation between Bo and naturally occurring immunoglobulins. Complement in sera from two severely hypogammaglobulinemic patients was not activated by Bo, but was made reactive by addition of purified human immunoglobulin G.