Apolipoprotein A-I gene expression in transgenic mice.
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Animals↗
Biomedical subjects
A Walsh
Publications and source records attributed to A Walsh.
Accumulation of human apolipoprotein E in the plasma of transgenic mice.
Three separate lines of transgenic mice were created with integrated copies of an 11.1-kilobase pair human DNA fragment containing the apolipoprotein (apo) E gene. The endogenous mouse apoE gene is primarily expressed in the liver with varying levels of expression in other tissues. However, in all three transgenic lines high levels of human apoE mRNA were detected only in the kidney, with lower levels found in the liver and other tissues; despite this profile of human apoE mRNA, human apoE was found in the plasma of the transgenic mice at levels comparable to those found in human plasma. All of the human apoE in the plasma of the transgenic mice was associated with lipoproteins. These results suggest that the domain responsible for the high level of apoE expression in liver lies outside of the microinjected DNA fragment and that an ectopic site of expression of an introduced gene may be permissive for the accumulation of its protein in plasma.
Animals↗
Hypertriglyceridemia as a result of human apo CIII gene expression in transgenic mice.
Primary and secondary hypertriglyceridemia is common in the general population, but the biochemical basis for this disease is largely unknown. With the use of transgenic technology, two lines of mice were created that express the human apolipoprotein CIII gene. One of these mouse lines with 100 copies of the gene was found to express large amounts of the protein and to be severely hypertriglyceridemic. The other mouse line with one to two copies of the gene expressed low amounts of the protein, but nevertheless manifested mild hypertriglyceridemia. Thus, overexpression of apolipoprotein CIII can be a primary cause of hypertriglyceridemia in vivo and may provide one possible etiology for this common disorder in humans.
Animals↗
Tissue-specific methylation patterns and expression of the human apolipoprotein AI gene.
To better understand the tissue-specific expression of the human apolipoprotein (apo)AI gene, we performed a detailed analysis of the pattern of methylation of the gene in various human adult and embryonic tissues and in tissues of transgenic mice harboring the human apo-AI gene. In addition, the gene was analyzed also in liver and intestine-derived human cell lines (HepG2 and Caco2, respectively). Using methyl-sensitive restriction enzymes (HpaII, HhaI, and SmaI) and the appropriate radioactive probes, we were able to determine separately the status of methylation of the 5'-end, the body of the gene, and 3'-end flanking sequences. The apo-AI gene in tissues that express the gene was undermethylated at the 5'-end. However, the 5'-end of the gene in sperm and in all adult tissues that do not express the gene was heavily methylated. The body of the gene which contains a CpG island and the 3'-end flanking sequences were, in general, hypomethylated except for specific sites that showed partial methylation. In contrast, while the gene showed tissue-specific expression already in a 12-week-old embryo, the 5'-end was invariably hypomethylated in all tissues of the embryo. A human apo-AI transgene has recently been shown to be active exclusively in the liver, while the endogenous gene is expressed in both liver and intestine (6). We show here that the 5'-end of the apo-AI transgene was methylated in all tissues of the mouse (including intestine) except liver. The results presented here demonstrate a clear correlation between hypomethylation of the 5'-end and activity of the apo-AI gene. However, the observed methylation pattern of the gene in embryonic tissues suggests that tissue-specific expression precedes formation of the tissue-specific methylation pattern.
Animals↗
Desmosomes, corneosomes and desquamation. An ultrastructural study of adult pig epidermis.
We recently developed a pig skin model to determine the role of corneosomes (modified desmosomes in the stratum corneum) and extracellular lipids in desquamation. The present study provides control morphometric data on the morphological changes in desmosomes and corneosomes leading to desquamation in adult pig epidermis in vivo. The extracellular space within desmosomes gradually widened from the basal to the granular layer, and decreased slightly in the stratum corneum. Mid-dense line broadening, and increased electron density of the distal light layers, coincided with membrane-coating granule extrusion in the outer granular layer. Corneocyte attachment correlated with corneosome distribution. Compactum packing was relatively tight and corneosomes were numerous. Cohesion was mainly peripheral in the disjunctum, and corneosomes were restricted to corneocyte edges. Adhesion had a tongue-and-groove appearance with corneosomes riveting corneocyte peripheries into a lipped groove on adjoining cells. Cells shed by peeling radially towards the lipped groove, and corneosomes decreased from lower to upper disjunctum. Corneosome breakdown commenced with an electron lucent band forming between the plug and lipid envelope. The plug was then unzipped from the lipid envelope and degraded. Corneosomes did not form squamosomes.
Animals↗
Genetic polymorphisms of Q region genes from wild-derived mice: implications for Q region evolution.
Both serological and DNA sequence analyses were performed to determine the extent of genetic polymorphism in Q region genes. A panel of Qa-2-specific monoclonal antibodies (mAbs) was tested on 35 wild-derived and inbred mouse strains. Members of this reagent panel recognize multiple and distinct epitopes on the Qa-2-bearing molecule(s). Although quantitative variations in Qa-2 levels were observed, no structural polymorphisms were detected. All strains were either entirely positive or entirely negative with the complete set of reagents. Moreover, cell surface Qa-2 expression was not significantly affected by differences in age or sex of the mouse or cell cycle status. To confirm this apparent lack of genetic polymorphism, the polymerase chain reaction (PCR) technique was used to amplify a portion of the 3' end of the Q region genes, Q4 to Q9, from several independent wild-derived strains of mice. Sequence analysis of the amplified material revealed very little evidence of nucleotide divergence. All strains tested had a Q even DNA sequence identical to that of Q6/Q8 in the B10 strain. Likewise, all tested strains had a Q odd DNA sequence identical to Q7/Q9 in the B10 strain. Two strains showed additional Q even sequences, while all strains tested possessed additional Q odd sequences. The observed lack of polymorphism suggests that the Q genes have evolved in a different manner from H-2K and H-2D. Moreover, duplications of these genes appear to have arisen prior to nucleotide sequence divergence.
Aging↗
Illegitimacy, child abuse and neglect, and cognitive development.
This study explored the relationship between illegitimate birth and cognitive development among 513 boys on probation. Prior research has shown that being part of a single-parent household leads to diminished verbal capacities and often puts a child in greater danger of abuse and neglect. Frequent abuse is thought to lead to the enhancement of visual and spatial skills relative to verbal skills through a process of "frozen watchfulness". I hypothesized that illegitimate boys from one-parent homes would have greater verbal-performance discrepancy scores than would boys from other combinations of birth status and family structure. These boys had the lowest verbal IQ and highest performance IQ scores and, hence, the largest discrepancy. These boys also suffered the highest degree of abuse and neglect of all four birth status/family structure combinations studied.
Child↗
Effect of ultraviolet-B radiation on protein synthesis in cultured lens epithelial cells.
Exposure of cultured rabbit lens epithelial cells to repetitive doses of UV-B radiation delays their growth and alters the synthesis of specific proteins. Irradiated cells on the shoulder of the survival curve exhibited a dose-dependent decrease in growth when subcultured in serum-supplemented medium. UV-B irradiation did not affect the subsequent attachment efficiency of the cells. Control and UV-B irradiated cells were incubated with [35S]methionine and the pattern of protein synthesis in the cells was analyzed by SDS-PAGE and autoradiography. Analysis of the labeled proteins from cells exposed to UV-B radiation showed the induction of a 32 kD polypeptide and the loss of a 26 kD polypeptide compared with controls. Analysis of the proteins released by the UV-B irradiated cells into the culture medium revealed the 50% loss of a 37 kD radiolabeled protein compared with controls. The alteration of protein synthesis in lens epithelial cells by UV-B radiation may contribute to cataract formation.
Animals↗
Urology in the twenty-first century.
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Forecasting↗
Aggressive surgery for malignant supratentorial gliomas.
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Brain Neoplasms↗
High levels of human apolipoprotein A-I in transgenic mice result in increased plasma levels of small high density lipoprotein (HDL) particles comparable to human HDL3.
Five lines of transgenic mice, which had integrated the human apolipoprotein (apo) A-I gene and various amounts of flanking sequences, were established. Normally, apoA-I is expressed mainly in liver and intestine, but all of the transgenic lines only expressed apoA-I mRNA in liver, strongly suggesting that 256 base pairs of 5'-flanking sequence was sufficient for liver apoA-I gene expression but that 5.5 kilobase pairs was not sufficient for intestinal expression. Mean plasma levels of human apoA-I varied in different lines from approximately 0.1 to 200% of normal mouse levels. This was not dependent on the amount of flanking sequence. Lipoprotein levels were studied in detail in one of the lines with a significantly increased apoA-I pool size. In one study, the total plasma apoA-I level (mouse plus human) was 381 +/- 43 mg/dl in six animals from this line, compared to 153 +/- 17 mg/dl in matched controls. Total and high density lipoprotein cholesterol (HDL-C) levels were increased 60% in transgenic animals, compared to controls (total cholesterol: 125 +/- 12 versus 78 +/- 13 mg/dl, p = 0.0001; HDL-C 90 +/- 7 versus 55 +/- 11 mg/dl, p = 0.0001). The molar ratio of HDL-C/apoA-I was significantly lower in transgenic animals, 17 +/- 1 versus 25 +/- 2 (p = 0.0001), suggesting the increase was in smaller HDL particles. This was confirmed by native gradient gel electrophoresis. This was not due to aberrant metabolism of human apoA-I in the mouse, since human apoA-I was distributed throughout the HDL particle size range and was catabolized at the same rate as mouse apoA-I. In another study of 23 transgenic mice, HDL-C and human apoA-I levels were highly correlated (r = 0.87, p less than 0.001). The slope of the correlation line also indicated the additional HDL particles were in the smaller size range. We conclude that human apoA-I can be incorporated into mouse HDL, and excessive amounts increase HDL-C levels primarily by increasing smaller HDL particles, comparable to human HDL3 (HDL-C/apoA-I molar ratio = 18).
Animals↗
Love, self-esteem, and multiple sclerosis.
Multiple sclerosis (MS) is a progressive chronic disease which generally appears in early adulthood. The debilitating symptoms of MS can have adverse effects on the sufferer's self-esteem, a vital coping resource for sufferers of chronic diseases. This study explores the effects of positive affect and social isolation--conceived broadly together as love--on self-esteem. We found that love was the most powerful predictor of self-esteem, followed by attitude stage, number of years since diagnosis, social class, and physical restriction.
Activities of Daily Living↗
What is it? What could injections have to do with this arterial occlusion?
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Adult↗
Membrane-coating granules are acidic organelles which possess proton pumps.
Lysosomes are by definition organelles that maintain an internal acidic pH and contain hydrolytic enzymes. Membrane-coating granules contain a battery of hydrolytic enzymes, in addition to their lamellar discs, and are therefore commonly assumed to be lamellate lysosomes. Although there are data confirming the existence of enzymes in membrane-coating granules, there is no direct evidence to suggest that their internal pH is acidic. As part of a wider program on their role in desquamation, our aim was to determine whether membrane-coating granules are indeed acidic and possess proton pumps. Chloroquine and monensin were selected as the pH markers because both induce swelling of acidic organelles. In four repeat experiments dermatome slices of pig ear skin (2 mm2 x 0.5 mm) were incubated as organ cultures either alone (control) or with 1 mM chloroquine or 25 microM monensin. Ultrastructural observations revealed no swelling in control specimens. In contrast, the inclusion of chloroquine or monensin caused swelling of specific organelles including membrane-coating granules, lysosomes, and trans elements of Golgi stacks, but not mitochondria, rough endoplasmic reticulum, or nuclear envelopes. Swelling of membrane-coating granules and the other organelles was prevented by pretreatment with N,N'-dicyclohexylcarbodiimide, a known inhibitor of lysosomal H+ ATPase activity. These findings suggest that membrane-coating granules actively maintain an acidic interior with the aid of proton pumps. Furthermore, membrane-coating granules are heterogeneous because swelling of the whole population did not commence simultaneously. However, it remains to be determined whether this heterogeneity reflects variations in membrane-coating granule pH, leakiness of their membranes to cations, or the number or activity of their proton pumps.
Animals↗
A fully differentiating epidermal model with extended viability: development and partial characterization.
A highly differentiated porcine skin organ culture model has been developed for future investigations of membrane-coating granules (MCG) and their role in epidermal differentiation. In contrast to many previous systems, cultures do not undergo necrosis of the upper epidermis or display dermo-epidermal separation, but survive for at least 3 weeks, at which time mitotic cells are still evident. Although rete projections are gradually smoothed out and the viable epidermis thins at a rate of approximately 0.35 cells per day, the stratum corneum gains approximately 1.5 corneocytes per day. Furthermore, at 3 weeks all the major differentiation markers are expressed, including keratohyalin granules, MCG, and an orthokeratotic stratum corneum. The system is inexpensive, simple to establish, and does not require elevated oxygen levels. The main requirements are 1) the use of Dulbecco's minimal essential medium supplemented with 2) hydrocortisone (100 micrograms/ml), 3) growth at an air/liquid interface, and 4) attached connective tissue. The further addition of vitamin C (300 micrograms/ml) and/or bovine serum albumin (2 mg/ml) offered no obvious advantage. Degeneration of organ cultures in standard cell culture media was discovered to be caused by fetal bovine serum (FBS). FBS-induced degeneration was not prevented by adding any of the supplements tested, or the inclusion of 3T3 fibroblasts, even when culturing at an air/liquid interface. Complete submersion rapidly killed specimens, presumably through oxygen starvation. The ability to maintain a fully keratinizing system for several weeks, in a totally chemically defined medium, will prove valuable for research not only into the role(s) of MCG in epidermal biology but also studies of desquamation and epidermal differentiation.
Animals↗
Progesterone and estradiol modulate interleukin-1 beta messenger ribonucleic acid levels in cultured human peripheral monocytes.
The relationship between the endocrine system and immune monokines, such as interleukin-1 (IL-1), is of increasing interest. IL-1, a protein secreted by peripheral monocytes and tissue macrophages, mediates a wide variety of immune responses, and its production appears to be inversely related to the level of gonadal steroids. In this report, we have investigated the relationship between estradiol and progesterone concentrations and the level of IL-1 beta mRNA in cultured human peripheral monocytes and pelvic macrophages. Human peripheral monocytes, isolated during the luteal phase of the menstrual cycle, were activated with lipopolysaccharide (10 micrograms/mL). Cellular RNA was isolated and analyzed by Northern analysis using an 800-basepair IL-1 beta cDNA probe. Hybridization with 32P-labeled probe showed maximal levels of IL-1 beta mRNA occurring between 3 and 7 h of culture. Cultures of lipopolysaccharide-activated human peripheral monocytes incubated for 3-6 h with increasing amounts of progesterone or estradiol (0-10(-5) M) in the presence of either 5% fetal calf serum or 0.1% BSA demonstrated an inverse relationship between IL-1 beta mRNA levels and steroid concentration. In both cases, IL-1 beta mRNA levels decreased by 80-90% as the progesterone concentration increased to 10(-5) M and by 70-90% as the estradiol concentration increased similarly. A similar 80% decrease in IL-1 beta mRNA was observed with peritoneal macrophages incubated with increasing amounts of progesterone. This reciprocal relationship between IL-1 beta mRNA and gonadal steroids may have important ramifications in reproductive biology for both embryonic implantation and fetal survival as well as for clinically relevant changes in bone mass.
Adult↗
Reoperation for malignant astrocytoma.
We evaluated 15 consecutive patients with malignant astrocytomas who were reoperated for functional status and survival. Their Karnovsky Performance Status (KPS) was not changed by surgery. None suffered perioperative death, wound infection, or complications. Patients with glioblastoma maintained KPS unchanged for a mean of 13 weeks (median, 10 weeks); with anaplastic astrocytoma, mean, 37.2 weeks (median, 24 weeks). Life spans were approximately twice that of non-reoperated historical controls. Reoperation for patients with recurrent malignant astrocytoma should be seriously considered when a gross total re-resection can be the goal in a patient whose tumor is in an accessible brain region.
Adult↗
Patient satisfaction within an emergency department: the impact of a hospital volunteer program.
During the past decade, the proliferation of managed care plans and the reduction of governmental reimbursement has seriously eroded hospital revenues. As a result, hospitals are managing with less resources yet confronting more complex patient problems, particularly in the Emergency Department of the hospital. Since the Emergency Department is frequently the major interface between the hospital and the community, it is essential that patients have a positive experience while obtaining care. This study explores the impact of a hospital-based volunteer program upon patient satisfaction within an Emergency Department and the implications for hospital administrators.
Consumer Behavior↗