The complete nucleotide sequence of the domestic dog (Canis familiaris) mitochondrial genome

The complete nucleotide sequence of the mitochondrial genome of the domestic dog, Canis familiaris, was determined. The length of the sequence was 16,728 bp; however, the length was not absolute due to the variation (heteroplasmy) caused by differing numbers of the repetitive motif, 5'-GTACACGT(A/G)C-3', in the control region. The genome organization, gene contents, and codon usage conformed to those of other mammalian mitochondrial genomes. Although its features were unknown, the "CTAGA" duplication event which followed the translational stop codon of the COII gene was not observed in other mammalian mitochondrial genomes. In order to determine the possible differences between mtDNAs in carnivores, two rRNA and 13 protein-coding genes from the cat, dog, and seal were compared. The combined molecular differences, in two rRNA genes as well as in the inferred amino acid sequences of the mitochondrial 13 protein-coding genes, suggested that there is a closer relationship between the dog and the seal than there is between either of these species and the cat. Based on the molecular differences of the mtDNA, the evolutionary divergence between the cat, the dog, and the seal was dated to approximately 50 +/- 4 million years ago. The degree of difference between carnivore mtDNAs varied according to the individual protein-coding gene applied, showing that the evolutionary relationships of distantly related species should be presented in an extended study based on ample sequence data like complete mtDNA molecules.

High plains disease of corn and wheat: ultrastructural and serological aspects

Virus-like particles with unique size and morphology were consistently associated with a new eriophyid mite-borne disease of maize and wheat, the high plains disease. In cells of symptomatic leaves, double membrane-bound particles (DMPs), quasi-spherical structures 120-200 nm in diameter, were present throughout the cytoplasm in association with electron-dense amorphous inclusions. No DMPs and inclusions were observed in symptomless plants. The DMPs were morphologically indistinguishable from those associated with eriophyid mite-borne diseases of uncertain etiology: fig mosaic, rose rosette, yellow ringspot of redbud, thistle mosaic, wheat spot chlorosis and wheat spot mosaic diseases. The DMPs and associated viroplasm-like inclusions in maize and wheat were specifically immunogold labeled in situ with an antiserum to the 32 kDa protein associated specifically with the high plains disease. Thread-like structures, present in the purified preparations from diseased maize were also immunogold labeled with the antiserum. It is suggested that the thread-like structures are derived from the DMPs. In many cells of symptomatic maize and wheat samples, DMPs occurred together with flexuous rod-shaped particles and cylindrical inclusions of wheat streak mosaic potyvirus (WSMV), indicating that these cells are infected doubly with WSMV and the agent represented by the DMPs.

The comparative anatomical study of the parietal region of the skull of the Korean native goat (Capra hircus)

In the skull of the Korean native goat, the parietal region was classified into four types by the degree of the fusion of the bones, the os interparietale, the os parietale and the squama occipitalis of the os occipitale, and the structural variations of these fusions. The fusion appeared first in the sutura interparietoparietalis and that of the sutura sagittalis of both ossa parietalia was followed. There was no fusion between the os parietale and the squama occipitalis of the os occipitale. These results suggest that the os interparietale developed independently but fused to the os parietale after birth, and the os parietale were developed as paired bones in prenatal life and then fused together according to age.

Identification and characterization of potential cis-regulatory elements governing transcriptional activation of the rat tyrosine hydroxylase gene

Tyrosine hydroxylase (TH) catalyzes the conversion of L-tyrosine to 3,4-dihydroxy-L-phenylalanine, which is the first and rate-limiting step in catecholamine biosynthesis. We have previously shown that the cyclic AMP response element (CRE), an essential promoter element for both basal and cyclic AMP-inducible TH transcription, activates the promoter activity in a distance-dependent manner. To identify further cis-regulatory elements controlling TH gene expression, we analyzed the potential regulatory sequences by several approaches. First, using transient transfection assays, we examined the cell-specific promoter activities of TH-reporter gene constructs and a dopamine beta-hydroxylase (DBH)-reporter construct containing the 5' upstream sequences of the rat TH and human DBH genes, respectively, that had been shown to direct tissue-specific reporter expression in transgenic mice experiments. Second, DNase I footprinting analysis of the 503-bp proximal area of the rat TH gene identified seven footprinted regions that encompass the putative cis-regulatory motifs, including the CRE (domain 1), Sp1 (domain III), Octamer (domain IV), AP1 (domain V), AP2 (domain VI), and two potentially novel sequence motifs (domains II and VII). Footprinting patterns at these sites by nuclear proteins from TH-positive and -negative cell lines appeared to be similar. Third, site-directed mutagenesis demonstrates that domain III, but not domain II, critically contributes to the TH promoter activity. Furthermore, electrophoretic mobility shift, competition, and supershift assays demonstrate that domain III is an authentic Sp1 site and that the transcription factor Sp1 interacts with it. This and previous results suggest that the CRE and Sp1 site may synergistically activate TH transcription in a promoter context-dependent manner.

Binding of amyloid beta-protein to intracellular brain proteins in rat and human

Amyloid beta-protein (Abeta), in its soluble form, is known to bind several circulatory proteins such as apolipoprotein (apo) E, apo J and transthyretin. However, the binding of Abeta to intracellular proteins has not been studied. We have developed an overlay assay to study Abeta binding to intracellular brain proteins. The supernatants from both rat and human brains were found to contain several proteins that bind to Abeta 1-40 and Abeta 1-42. No major difference was observed in the Abeta binding-proteins from brain supernatants of patients with Alzheimer's disease and normal age-matched controls. Binding studies using shorter amyloid beta-peptides and competitive overlay assays showed that the binding site of Abeta to brain proteins resides between 12-28 amino acid sequence of Abeta. The presence of several intracellular Abeta-binding (AbetaB) proteins suggests that these proteins may either protect Abeta from its fibrillization or alternatively promote Abeta polymerization. Identification of these proteins and their binding affinities for Abeta are needed to assess their potential role in the pathogenesis of Alzheimer's disease.

Follicular cells affect the fertilizability and developmental competency of bovine oocytes in vitro

The present study examined the time-dependent effects of follicular cells on the fertilizability of oocytes and their subsequent development to blastocysts. The percentages of oocytes reaching the metaphase-II stage of maturation rose from 51.3% after 16 h of culture to 86.2% at 28 h (cumulus-intact oocytes; CIO) and, for the same time points, from 65.4% to 83.3% (corona-enclosed oocytes; CO) and 54.3% to 88.9% (denuded oocytes; DO), respectively. When DO were cultured for more than 24 h before insemination, fertilization rates were significantly lower compared with CIO and CO. The maximum rates of development to blastocysts were observed when the oocytes were cultured for 24 h in the CIO group (22.1%), 20 h in the CO group (19.7%) and 18 h in the DO group (9.2%), respectively. These results suggest that (i) the presence of cumulus cells or corona cells during maturation is not necessary for nuclear maturation of oocytes; (ii) the attachment of corona cells to the oocytes during maturation is important for the further development to the blastocyst stage, and (iii) the presence of attached cumulus and/or corona cells during maturation in vitro extends the maturation period required for further development to the blastocyst stage.

Endotoxin-induced migration of monocytes and PECAM-1 phosphorylation are abrogated by PAF receptor antagonists

The trafficking of monocytes across the endothelial lining of the blood vessel increases in response to bacterial infection at sites of inflammation. However, the molecular events involved in the diapedesis of monocytes in response to endotoxin are not completely understood. Our studies revealed that signaling by lipopolysaccharide (LPS) in human umbilical vein endothelial cells (HUVEC) resulted in a threefold increase in the transendothelial migration of monocyte-like HL-60 cells and a sevenfold increase in the phosphorylation of platelet endothelial cell adhesion molecule-1 (PECAM-1). The transmigration induced by LPS was inhibited by an antibody to PECAM-1. Both the phosphorylation of PECAM-1 and transendothelial migration of monocytes were inhibited by a platelet-activating factor (PAF) receptor antagonist, indicating the autocrine effect of PAF in these events. Treatment of HUVEC with LPS caused a fourfold increase in PAF receptor mRNA expression that was completely blocked by the PAF receptor antagonist. We conclude that PAF, generated by HUVEC in response to LPS or gram-negative bacterial infection, acts in an autocrine manner, causing PECAM-1 phosphorylation and thus the transendothelial migration of monocytes.

Recanalization of obstructed Tenckhoff peritoneal dialysis catheter: wire/stylet manipulation combined with endoluminal electrocauterization

We report the results of fluoroscopically guided wire/stylet manipulation combined with endoluminal electrocauterization in seven patients with obstructed Tenckhoff peritoneal dialysis catheters. In preparation for clinical application, electrocauterization was performed using a stone basket to recanalize surgically removed Tenckhoff catheters obstructed with omental fat ingrowing through the side holes. All ingrowing omental fat was removed easily by electrocauterization with the rotating movement of a stone basket. The technique was then applied in vivo in seven cases with ingrowing omental fat and malpositioned catheter; six (86%) were successfully recanalized. Among those six cases with initial success, four maintained good catheter function with durable patency (mean 261.3 days). No significant complication was noted.

Three-year multicenter surveillance of systemic pneumococcal infections in children

OBJECTIVE

To track antibiotic susceptibility of Streptococcus pneumoniae isolates obtained from children with systemic infections and determine outcome of treatment.

DESIGN

A 3-year (September 1993 through August 1996) prospective surveillance study of all invasive pneumococcal infections in children.

PATIENTS

Infants and children cared for at eight children's hospitals in the United States with culture-proven systemic pneumococcal infection.

RESULTS

One thousand two hundred ninety-one episodes of systemic pneumococcal infection were identified in 1255 children. An underlying illness was present in the children for 27% of the episodes. The proportion of isolates that were nonsusceptible to penicillin or ceftriaxone increased annually and nearly doubled throughout the 3-year period; for the last year the percentages of isolates nonsusceptible to penicillin and ceftriaxone were 21% and 9.3%, respectively. There was no difference in mortality between patients with penicillin-susceptible or nonsusceptible isolates. Only 1 of 742 patients with bacteremia had a repeat blood culture that was positive > 1 day after therapy was started. All 24 normal children with bacteremia attributable to isolates resistant to penicillin had resolution of their infection; the most common treatment regimen was a single dose of ceftriaxone followed by an oral antibiotic.

CONCLUSIONS

The percentage of pneumococcal isolates nonsusceptible to penicillin and ceftriaxone increased yearly among strains recovered from children with systemic infection. Because empiric antibiotic therapy already has changed for suspected pneumococcal infections, antibiotic resistance has not been associated with increased mortality. Careful monitoring of antibiotic susceptibility and outcome of therapy is necessary to continually reassess current recommendations for treatment.

A requirement for the rac1 GTPase in the signal transduction pathway leading to cardiac myocyte hypertrophy

We have used adenoviral-mediated gene transfer of a constitutively active (V12rac1) and dominant negative (N17rac1) isoform of rac1 to assess the role of this small GTPase in cardiac myocyte hypertrophy. Expression of V12rac1 in neonatal cardiac myocytes results in sarcomeric reorganization and an increase in cell size that is indistinguishable from ligand-stimulated hypertrophy. In addition, V12rac1 expression leads to an increase in atrial natriuretic peptide secretion. In contrast, expression of N17rac1, but not a truncated form of Raf-1, attenuated the morphological hypertrophy associated with phenylephrine stimulation. Consistent with the observed effects on morphology, expression of V12rac1 resulted in an increase in new protein synthesis, while N17rac1 expression inhibited phenylephrine-induced leucine incorporation. These results suggest rac1 is an essential element of the signaling pathway leading to cardiac myocyte hypertrophy.

Neuromuscular interaction between cisatracurium and mivacurium, atracurium, vecuronium or rocuronium administered in combination

We compared the dose-response relationships of cisatracurium, mivacurium, atracurium, vecuronium and rocuronium and examined the interactions of cisatracurium with mivacurium, atracurium, vecuronium and rocuronium in humans by isobolographic and fractional analyses. We studied 180 adult patients during nitrous oxide-fentanyl-propofol anaesthesia. Neuromuscular block was monitored using mechanomyography to detect the twitch response of the ulnar nerve at the wrist. The dose-response curves were determined by probit analysis. The calculated ED50 values and their 95% confidence intervals were 40.9 (38.1-43.7), 49.8 (47.0-52.6), 187.2 (175.1-199.3), 36.6 (34.7-38.5) and 136.4 (129.2-143.6) micrograms.kg-1 for cisatracurium, mivacurium, atracurium, vecuronium and rocuronium, respectively. Corresponding ED95 values were 57.6 (53.5-61.7), 91.8 (88.1-95.5), 253.1 (238.9-267.3), 52.9 (49.1-56.7) and 288.7 (276.2-301.2) micrograms.kg-1, respectively. The interaction between cisatracurium and mivacurium, vecuronium or rocuronium was found to be synergistic, but the interaction between cisatracurium and atracurium was found to be additive. Synergy between cisatracurium and vecuronium or rocuronium was greater than between cisatracurium and mivacurium.

Solution structure of eotaxin, a chemokine that selectively recruits eosinophils in allergic inflammation

The solution structure of the CCR3-specific chemokine, eotaxin, has been determined by NMR spectroscopy. The quaternary structure of eotaxin was investigated by ultracentrifugation and NMR, and it was found to be in equilibrium between monomer and dimer under a wide range of conditions. At pH </= 5 and low ionic strength, eotaxin was found to be predominantly a monomer. The three-dimensional structure of the eotaxin monomer solved at pH 5.0 revealed that it has a typical chemokine fold, which includes a 3-stranded beta-sheet and an overlying alpha-helix. Except for the N-terminal residues (residues 1-8), the core of the protein is well defined. The eotaxin structure is compared with the chemokines regulated upon activation, normal T-cell expressed and secreted (RANTES) and monocyte chemoattractant protein-1 (MCP-1); eotaxin binds only CC chemokine receptor CCR3, whereas RANTES binds many receptors including CCR3, and MCP-1 binds a distinct receptor, CCR2. The RMSD of the eotaxin ensemble of structures with the RANTES average minimized monomeric subunit is 5.52 +/- 0.87 A over all backbone atoms and 1.14 +/- 0.09 A over backbone atoms of residues 11-28 and 34-65. The most important difference between the structures is in the N-terminal residues that are unstructured in eotaxin but structured in RANTES and MCP-1. Several residues in the loop region of RANTES show similar packing in eotaxin (residues 11-17). As the N-terminal and loop regions have been shown to be critical for receptor binding and signaling, this structure will be useful for determining the basis for CCR3 selectivity of the eotaxin.

Differential thymic selection outcomes stimulated by focal structural alteration in peptide/major histocompatibility complex ligands

The T lineage repertoire is shaped by T cell receptor (TCR)-dependent positive and negative thymic selection processes. Using TCR-transgenic (N15tg) beta2-microglobulin-deficient (beta2m-/-) RAG-2(-/-) H-2(b) mice specific for the VSV8 (RGYVYQGL) octapeptide bound to Kb, we identified a single weak agonist peptide variant V4L (L4) inducing phenotypic and functional T cell maturation. The cognate VSV8 peptide, in contrast, triggers negative selection. The crystal structure of L4/Kb was determined and refined to 2.1 A for comparison with the VSV8/Kb structure at similar resolution. Aside from changes on the p4 side chain of L4 and the resulting alteration of the exposed Kb Lys-66 side chain, these two structures are essentially identical. Hence, a given TCR recognizes subtle distinctions between highly related ligands, resulting in dramatically different selection outcomes. Based on these finding and the recent structural elucidation of the N15-VSV8/Kb complex, moreover, it appears that the germ-line Valpha repertoire contributes in a significant way to positive selection.

Human blood-brain barrier receptors for Alzheimer's amyloid-beta 1- 40. Asymmetrical binding, endocytosis, and transcytosis at the apical side of brain microvascular endothelial cell monolayer

A soluble monomeric form of Alzheimer's amyloid-beta (1-40) peptide (sAbeta1-40) is present in the circulation and could contribute to neurotoxicity if it crosses the brain capillary endothelium, which comprises the blood-brain barrier (BBB) in vivo. This study characterizes endothelial binding and transcytosis of a synthetic peptide homologous to human sAbeta1-40 using an in vitro model of human BBB. 125I-sAbeta1-40 binding to the brain microvascular endothelial cell monolayer was time dependent, polarized to the apical side, and saturable with high- and low-affinity dissociation constants of 7.8+/-1.2 and 52.8+/-6.2 nM, respectively. Binding of 125I-sAbeta1-40 was inhibited by anti-RAGE (receptor for advanced glycation end products) antibody (63%) and by acetylated low density lipoproteins (33%). Consistent with these data, transfected cultured cells overexpressing RAGE or macrophage scavenger receptor (SR), type A, displayed binding and internalization of 125I-sAbeta1-40. The internalized peptide remains intact > 94%. Transcytosis of 125I-sAbeta1-40 was time and temperature dependent, asymmetrical from the apical to basolateral side, saturable with a Michaelis constant of 45+/-9 nM, and partially sensitive to RAGE blockade (36%) but not to SR blockade. We conclude that RAGE and SR mediate binding of sAbeta1-40 at the apical side of human BBB, and that RAGE is also involved in sAbeta1-40 transcytosis.

Cocaine enhances monocyte migration across the blood-brain barrier. Cocaine's connection to AIDS dementia and vasculitis?

Cocaine has wide-ranging effects on the immune and neuroendocrine systems (Fiala et al., 1996) resembling an inflammatory "stress" response with upregulation of pro-inflammatory cytokines and stimulation of the HPA axis (Gan et al., 1997). Cocaine abuse has also been associated with vascular pathology, including vasculitis, vasospasm and hemorrhage. These effects suggest that cocaine could perturb the function of endothelial cells, including the blood-brain barrier, and influence the progression to AIDS in HIV-infected individuals (Shapshak et al., 1997; Goodkin et al., 1997). In order to understand clinical consequences of cocaine abuse, it is important to gain insight into molecular and cellular basis of cocaine's effects on immune and endothelial cells. Cocaine's in vitro effects on (a) permeability, (b) immune cell migration, (c) adhesion molecules, and (d) cytokine expression were investigated in a blood-brain barrier model constructed with brain microvascular endothelial cells and fetal astrocytes with the following results: (a) cocaine and tumor necrosis factor-alpha (TNF-alpha) increased the model's permeability to inulin similarly in a dose-responsive fashion; (b) cocaine (10(-4) to 10(-8_ M) enhanced monocyte migration across the barrier with the maximum increase, approximately 100%, by 10(-5) M cocaine; (c) cocaine treatment also increased the expression of endothelial adhesion molecules, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecules-1 (VCAM-1) and platelet/endothelial cell adhesion molecule-1 (PECAM-1); (d) although the cocaine in vitro effects on cytokine production by mononuclear cells have been difficult to assess due to a heterogeneity in the degree of responsiveness between individuals, the data suggest that mononuclear cells from cocaine addicts are sensitized to in vitro cocaine challenge with hypersecretion of inflammatory cytokines. Cocaine's in vivo manifestations are compatible with these in vitro effects: (A) chronic cocaine treatment of rats significantly increased rolling white blood cell flux, leukocyte-endothelium adhesion, and ICAM-1 expression in the mesentery (House et al., 1996); (B) cocaine injection to cocaine-dependent subjects tipped the balance of cytokine secretion by mononuclear cells to Th1-type (Gan et al., 1997), and (C) cocaine injection stimulated the hypothalamic-pituitary axis (HPA) to increase both anti- and pro-inflammatory hormonal secretion. Collectively, these results suggest that the immune effects of cocaine on endothelial, immune and neuroendocrine cells impair the function of the blood-brain, barrier, increase cell emigration from the blood vessels, in particular into the brain, and may cause vasculitis. These effects could also increase importation of HIV-1 into the brain.

Effect of hyperglycemia on brain cell membrane function and energy metabolism during hypoxia-ischemia in newborn piglets

The purpose of this study was to test the hypothesis that hyperglycemia ameliorates changes in brain cell membrane function and preserves cerebral high energy phosphates during hypoxia-ischemia in newborn piglets. A total of 42 ventilated piglets were divided into 4 groups, normoglycemic/normoxic(group 1, n=9), hyperglycemic/normoxic(group 2, n=8), normoglycemic/hypoxic-ischemic(group 3, n=13) and hyperglycemic/hypoxic-ischemic(group 4, n=12) group. Cerebral hypoxia-ischemia was induced by occlusion of bilateral common carotid arteries and simultaneous breathing with 8% oxygen for 30 min. Hyperglycemia (blood glucose 350-400 mg/dl) was maintained for 90 min before and throughout hypoxia-ischemia using modified glucose clamp technique. Changes in cytochrome aa3 were continuously monitored using near infrared spectroscopy. Blood and CSF glucose and lactate were monitored. Na+, K+-ATPase activity, lipid peroxidation products (conjugated dienes), tissue high energy phosphates (ATP and phosphocreatine) levels and brain glucose and lactate levels were determined biochemically in the cerebral cortex. During hypoxia-ischemia, glucose levels in blood and CSF were significantly elevated in hyperglycemic/hypoxic-ischemic group compared with normoglycemic/hypoxic-ischemic group, but lactate levels in blood and CSF were not different between two groups. At the end of hypoxia-ischemia of group 3 and 4, triangle up Cyt aa3, Na+, K+-ATPase activity, ATP and phosphocreatine values in brain were significantly decreased compared with normoxic groups 1 and 2, but were not different between groups 3 and 4. Levels of conjugated dienes and brain lactate were significantly increased in groups 3 and 4 compared with groups 1 and 2, and were significantly elevated in group 4 than in group 3 (0.30+/-0.11 vs. 0.09+/-0.02 micromol g-1 protein, 26.4+/-7.6 vs. 13.1+/-2.6 mmol kg-1, p<0.05). These findings suggest that hyperglycemia does not reduce the changes in brain cell membrane function and does not preserve cerebral high energy phosphates during hypoxia-ischemia in newborn piglets. We speculate that hyperglycemia may be harmful during hypoxia-ischemia due to increased levels of lipid peroxidation in newborn piglet.

Role of specific IgE, IgG and IgG4 antibodies to corn dust in exposed workers

BACKGROUND AND METHODS

To evaluate the role of specific antibodies to corn dust (CD) and their relationship to respiratory dysfunction, we detected serum specific IgE(slgE) and IgG4(slgG4) antibodies by ELISA in 42 employees working in the animal feed industry and 27 unexposed controls.

RESULTS

Our survey revealed that 15 (34.9%) subjects had work-related respiratory dysfunction associated with or without nasal symptoms. Among these subjects, eight had airway hyper-responsiveness to methacholine. Significant differences were noted in slgE and slgG4 between exposed and unexposed groups (p = 0.04, p = 0.00 respectively), but no difference was noted in slgG (p = 0.1). Although there was no significant differences in the prevalence of specific IgE antibody between symptomatic (29%) and asymptomatic groups (19%, p = 0.55), the specific IgE levels were significantly higher in symptomatic workers than in asymptomatic workers (p = 0.03). Specific IgG antibody was detected in 1 (6%) symptomatic and 4 (15%) asymptomatic workers (p = 0.46). Specific IgG4 antibody was detected in 11 (73%) of symptomatic and 21 (78%) of asymptomatic workers (p = 0.90). The higher prevalence of slgG4 antibody was noted in workers with slgE antibody (p = 0.001). The correlation between slgG and exposure duration was significant (r = 0.36, p = 0.02). There was no association between the prevalence of slgE, slgG, and slgG4 to exposure intensity, smoking or atopic status.

CONCLUSION

These results suggested that the existence of slgG and slgG4 might represent a response to CD exposure, and that some unexposed subjects had slgG to CD. Specific IgE might play a role in the development of respiratory symptoms.

A case of arteriovenous type cardiac hemangioma

Cardiac hemangiomas are rare primary tumors of the heart and constitute only 2.8% of primary cardiac tumors. They are classified into capillary, cavernous, epitheloid and arteriovenous type and the last one is the most uncommon type. We experienced a case of cardiac hemangioma which was diagnosed as arteriovenous type for the first time in Korea in the literature. The patient was a 54-year-old woman who presented with palpitation and anterior chest pain. The diagnosis was based upon coronary angiography which showed two tumor blushings located in the interatrial and interventricular septum with venous drainage to the coronary sinus and right atrium. Associated atrial fibrillation with rapid ventricular response was controlled with digitalis.

The cell-specific silencer region of the human dopamine beta-hydroxylase gene contains several negative regulatory elements

Dopamine beta-hydroxylase (DBH) catalyzes the conversion of dopamine to noradrenaline and is selectively expressed in noradrenergic and adrenergic neurons in the nervous system. Transient transfection assays have indicated that cell-specific transcription of the human DBH gene may require a cell-specific silencer region residing at -486 to -263 bp upstream of the transcription start site. This region includes a putative DBH negative regulatory element (DNRE) with sequence homology to the restrictive element-1 (RE1)/neuron-restrictive silencer element identified in many other neural-specific genes. However, DNRE exerted negative regulation in both neuronal and nonneuronal cells alike, and site-directed mutation of this element did not significantly diminish the repressive activity of the DBH silencer region. Furthermore, expression of RE1-silencing transcription factor/neuron-restrictive silencer factor repressed neither DBH nor tyrosine hydroxylase promoter activity. We now report identification of three protein binding sites in the silencer region of the human DBH gene: SI at -271 to -250 bp, SII at -316 to -295 bp, and SIII at -348 to -324 bp. In vitro binding studies showed that SI and SIII, but not SII, interact with nuclear proteins from DBH-negative cells in a cell-specific manner. Furthermore, SI and SIII preferentially repressed the heterologous thymidine kinase and homologous DBH proximal promoter activities in nonneuronal cells. Taken together, the cell-specific silencer function of the upstream DBH region appears to involve several cis-regulatory elements, including two cell-specific repressor elements, SI and SIII, and a general negative regulatory element, DNRE. Based on these data, we propose that a highly restricted pattern of DBH gene expression in (nor)adrenergic cells of the nervous system may be controlled by multiple negative regulatory elements/silencers.

The effects of age, apolipoprotein E phenotype and gender on the concentration of amyloid-beta (A beta) 40, A beta 4242, apolipoprotein E and transthyretin in human cerebrospinal fluid

OBJECTIVE

To test whether the concentrations of amyloid-beta (A beta) 40, A beta 42, apolipoprotein E (apoE) and transthyretin in the CSF of normal individuals, are linked to three factors which modulate the risk of Alzheimer's disease (AD): chronological age, gender, and the presence of the apoE4 allele.

METHODS AND RESULTS

Proteins were measured by enzyme-linked immunosorbent assays except for transthyretin, which was assayed by radial immunodiffusion. The apoE phenotype was determined by isoelectric focusing. While the CSF levels of A beta 42, apoE, and transthyretin are reported to be reduced in AD, we found no relationship between age, gene, or apoE phenotype and the level of any of these proteins in the CSF of nondemented individuals. The concentration of A beta 40 was not modulated by gender or apoE phenotype, but did decline significantly with age.

CONCLUSION

These results indicate that the changes observed in the CSF of AD patients are specific to the disease itself rather than the known risk factors.

Streptokinase secretion by Serratia marcescens signaled by the C-terminal 41 amino acid segment of metalloprotease

In order to investigate the secretion signal of Serratia marcescens metalloprotease (SMP) and examine the ability of the secretion signal to secrete foreign proteins, hybrid genes encoding the passenger-SMP C-terminal segments were constructed. As a passenger protein, streptokinase (SK) deprived of its signal peptide was used. Three kinds of SMP C-terminal segments containing 41, 80, or 220 amino acid residues were fused to the C-terminus of SK as secretion signals. The SK-SMP chimeric proteins containing 41 or 220 amino acid segments of the SMP C-terminus were secreted into the culture medium by the SMP transporter of S. marcescens. This result suggests that cytoplasmic SK is secreted into the external medium by the C-terminal segments of SMP and also shows that the smallest, 41 amino acid segment of the SMP C-terminus functions as a secretion signal of foreign proteins as well as SMP.

Longitudinal study of cerebrospinal fluid amyloid proteins and apolipoprotein E in patients with probable Alzheimer's disease

Levels of soluble amyloid beta protein (sAbeta), amyloid beta precursor protein (APP) and apolipoprotein E (apoE) were examined in cerebrospinal fluid (CSF) obtained twice, at baseline and after 3-year follow-up, from 25 patients with probable Alzheimer's disease (AD). Levels of sAbeta and apoE from patients with the apoE4 allele decreased with time, whereas the levels were similar in patients without apoE4 allele. Changes of sAbeta and apoE concentrations correlated significantly with those of mini-mental state examination (MMSE) scores. Levels of sAbeta did not change with time in patients with mild dementia, whereas they decreased significantly in patients with moderate dementia. ApoE concentrations decreased in both groups whereas APP levels were similar. We conclude that measurements of CSF sAbeta and apoE levels may be helpful in monitoring progression of the disease.

Plasma lipid alterations in African-American women with breast cancer

The purpose of this study was to examine the relationship between plasma lipid and lipoprotein levels, stage of disease and breast cancer risk in African-American women. The study population comprised 163 African-American women: patients (n = 58) and controls (n = 105), with mean ages of 57.2 years and 47.7 years respectively. Approximately 71% and 56% of the women with breast cancer and the control population, respectively, were postmenopausal. Those with cancer had significantly higher education levels, P < or = 0.01, and higher triglyceride levels compared to the controls, P < or = 0.001, but lower body mass index (BMI) levels, P < or = 0.01. There were no statistically significant differences observed in total cholesterol, high-density-lipoprotein-containing cholesterol and low-density-lipoprotein-containing cholesterol between the patients and controls. After adjustments for age, education, BMI, and menopausal status, triglycerides remained significantly and positively associated with breast cancer risk. The significant correlation between the high levels of triglycerides and breast cancer risk (odds ratio = 5.12) may be attributed to differences in lipid metabolism between the women with breast cancer and controls, or to the consequences of breast cancer.

Gamma irradiation and ozone treatment for inactivation of Escherichia coli O157:H7 in culture media

A study was conducted to investigate the reduction and elimination of Escherichia coli O157:H7 by the effects of gamma irradiation and ozone treatment. Log phase cells were found to be more sensitive to gamma irradiation than stationary phase cells. E. coli O157:H7 was found to be considerably more resistant to irradiation at -18 degrees C than at 20 degrees C. The D values for this organism for treatment with ozone in tryptic soy agar were higher than those for treatment with ozone in phosphate buffer. Gamma irradiation at a dose of 1.5 kGy or ozone treatment at a concentration of 3 to 18 ppm for 20 to 50 min was required to assure the elimination of E. coli O157:H7.