Family studies of the E1kE1s genotype for plasma cholinesterase

Six individuals in three families with a history of suxamethonium sensitivity have been found to have genotype E1kE1s. The biochemical data for the recognition of this genotype have been analysed and the mean values compared with similar parameters for the usual phenotype. Individuals with genotype E1kE1s will be sensitive to suxamethonium.     

Relationship of human pancreatic cholesterol esterase gene structure with lipid phenotypes.

Pancreatic cholesterol esterase is one of the enzymes that plays a pivotal role in cholesterol absorption. Differences in the genotype of this enzyme could affect the susceptibility of individuals to dyslipidemia and/or cardiovascular disease. We undertook this study to investigate if any correlation exists between restriction fragment length polymorphism in the human pancreatic cholesterol esterase gene and serum lipid levels. DNA from 96 healthy adults was restricted with Stu I, Southern blotted, and probed with cDNA of human pancreatic cholesterol esterase. Results revealed six distinct patterns which were classified as A, B, C, D, E, and F which had a population frequency of 1%, 34.5%, 49%, 12.5%, 1% and 2% respectively. Correlation of the distribution of lipid and lipoprotein levels by pattern and sex revealed a significant interaction between pattern type and HDL (p=0.03) in the most common group (group C) for males. Male patients of pattern C tended to have a lower LDL cholesterol than non-pattern C males (p=0.07); in addition, 80% of all males in the study population with LDL cholesterol under 100 mg/dl were found in pattern C. Thus, the most common Stu I RFLP genotype is associated with a favorable lipid phenotype. This report shows an association between the human pancreatic cholesterol esterase genotype and serum lipid levels. Further analysis of a larger study group with Stu I and alternative polymorphic restriction enzymes is warranted, to confirm this biologically plausible result.     

Contrasting effects of alpha and beta globin regulatory elements on chromatin structure may be related to their different chromosomal environments.

Expression of the human alpha and beta globin gene clusters is regulated by remote sequences, referred to as HS -40 and the beta-locus control region (beta-LCR) that lie 5-40 kb upstream of the genes they activate. Because of their common ancestry, similar organization and coordinate expression it has often been assumed that regulation of the globin gene clusters by HS -40 and the beta-LCR occurs via similar mechanisms. Using interspecific hybrids containing chromosomes with naturally occurring deletions of HS -40 we have shown that, in contrast to the beta-LCR, this element exerts no discernible effect on long-range chromatin structure and in addition does not influence formation of DNase I hypersensitive sites at the alpha globin promoters. These differences in the behaviour of HS -40 and the beta-LCR may reflect their contrasting influence on gene expression in transgenic mice and may result from the differing requirements of these elements in their radically different, natural chromosomal environments; the alpha cluster lying within a region of constitutively 'open' chromatin and the beta cluster in a segment of chromatin which opens in a tissue-specific manner. Differences in the hierarchical control of the alpha and beta globin clusters may exemplify more general differences in the regulation of eukaryotic genes which lie in similar open or closed chromosomal regions.     

A hollow-fiber bioreactor for expanding HIV-1 in human lymphocytes used in preparing an inactivated vaccine candidate

An inactivated HIV vaccine intended to elicit broadly neutralizing antibodies is designed to use a pool of population-prevalent HIV-1 from plasma (PHIV), isolated before evolution of antibody-mediated genetic mutations. A suitable cell substrate (CS) for isolating such PHIV is peripheral blood mononuclear cells (PBMC) after stimulating with phytohemagglutinin (PHA) and interleukin-2 (IL-2). Feasibility of employing a hollow-fiber bioreactor under optimized conditions was investigated for large-scale expansion and efficient recovery of concentrated PHIV. Each CS batch was infected in vitro with a prototype PHIV, the infected cells were introduced into the bioreactor for 7-10 days in co-culture, and the cell-free supernatants were assayed for p24 antigen as an index of HIV synthesis. PBMC versus CD8-depleted (CD8D) CS, 20kDa versus 5kDa molecular weight cut-off (MWCO) bioreactor cartridges, 7- versus 10-day culture periods, and varying concentrations of IL-2, fetal bovine serum (FBS) and glucose content in the medium were functionally evaluated for p24 yield. PBMC cultures in 20kDa MWCO cartridges with 15% FBS, 80IU/mL IL-2 and 2.0g/L glucose produced the highest p24 yield; however, CD8D-CS, 20-30% FBS and 80 IU/mL IL-2 within 5kDa cartridges and 2.0 g/L glucose in the circulating medium was more cost-effective for synthesis of virion p24.     

Advances in the serodiagnosis of blastomycosis

Blastomyces dermatitidis, the etiologic agent of blastomycosis, is endemic to certain areas of North America and other continents and can cause a variety of clinical manifestations that range from subclinical to life-threatening infections. Delineation of its ecology and epidemiology has been difficult because of the lack of rapid, sensitive, and specific noninvasive diagnostic tests. Despite efforts to develop such tests for clinical use, diagnosis of infection is still based on direct visualization of the organism in histopathologic or cytologic specimens and growth in the microbiologic laboratory. Serologic tests and skin testing have been hampered by low sensitivity and specificity caused by cross-reactivity with other endemic mycoses and are not commercially available. An antigen assay is now commercially available, but it also has significant cross-reactivity with other mycoses, especially histoplasmosis. The keys to diagnosis remain a high index of suspicion and knowledge of the disease’s varied clinical manifestations.     

Gingival crevicular fluid infiltrating CD14+ monocytes promote inflammation in periodontitis

Periodontitis is a condition that occurs because of inflammation-mediated tissue degeneration. Many studies have been conducted to identify inflammatory molecules in periodontitis, but the well-defined role of cells from the immune system in the progression of periodontitis as well as in gingival tissue degeneration has not been appropriately established. The objective of the present study was to characterize the monocytes isolated from the gingival crevicular fluid (GCF) in patients with periodontitis. GCF was obtained from periodontitis patients and healthy controls. Cytokine levels of CCL2 were evaluated by ELISA in GCF samples. CD14+ monocytes were separated using magnetic sorting from GCF. RT-qPCR was performed to assess the gene expression. Cytometric bead array analysis was performed to analyze the levels of cytokines and chemokines in the secretome of cells. CD14+ monocytes from GCF secreted higher levels of CCL2 and showed elevated expression of genes responsible for monocyte migration. Additionally, upon lipopolysaccharide stimulation, these monocytes secreted higher levels of inflammatory cytokines and chemokines. This investigation aids in understanding the inflammatory microenvironment of periodontitis by characterizing GCF in terms of infiltrated CD14+ monocytes, cytokines, and molecules secreted by these monocytes, which are specific for cellular differentiation.     

Reconstitution of carrier-mediated choline transport in proteoliposomes prepared from presynaptic membranes oftorpedo electric organ,and its internal and external ionic requirements

Summary Proteoliposomes made by a butanol-sonication technique from electric organ presynaptic membranes showed choline transport activity. In contrast to intact nerve terminals, the uptake of choline was dissociated from its conversion to acetylcholine in this preparation. The kinetics of choline uptake by proteoliposomes was best described by two Michaelis-Menten components. At a low concentration of choline, uptake was inhibited by hemicholinium-3 and required external Na⁺ and, thus, closely resembled high-affinity choline uptake by intact cholinergic nerve terminals. Choline transport could be driven by the Na⁺ gradient and by the transmembrane potential (inside negative) but did not directly require ATP. External Cl^–, but not a Cl^– gradient, was needed for choline transport activity. It is suggested that internal K⁺ plays a role in the retention of choline inside the proteoliposome. Proteoliposomes should prove a useful tool for both biochemical and functional studies of the highaffinity choline carrier.Abbreviations ACh acetylcholine - HC-3 hemicholinium-3 - ChAT choline acetyltransferase     

Telecentric design for digital-scanning-based HiLo optical sectioning endomicroscopy with an electrically tunable lens

Confocal endoscopy has been widely used to obtain fine optically sectioned images. However, confocal endomicroscopic images are formed by point-by-point scanning in both lateral and axial directions, which results in long image acquisition time. Here, an endomicroscope with telecentric configuration is presented to achieve nonmechanical and rapid axial scanning for volumetric fluorescence imaging. In our system, optical sectioning in wide-field fashion is obtained through HiLo imaging with a digital micromirror device. Axial scanning, without mechanical moving parts, is conducted by digital focus adjustment using an electrically tunable lens, offering constant magnification and contrast. We demonstrate imaging performance of our system with optically sectioned images using fluorescently labeled beads, as well as ex vivo mice cardiac tissue samples. Our system provides multiple advantages, in terms of improved scanning range, and reduced image acquisition time, which shows great potentials for three-dimensional biopsies of volumetric biological samples.