Optimal conditions for hybridization with oligonucleotides: a study with myc-oncogene DNA probes

Sensitivity Enhancement of MicroRNA Detection Using a Power-free Microfluidic Chip

We present a microRNA (miRNA) detection method that achieves enhanced sensitivity by means of a power-free microfluidic chip without the requirement of an external power source. The miRNA detection is completed by sandwich hybridization between probe DNAs and target miRNA with small sample volume (0.5 μL) within 20 min. Fluorescence signals after hybridization were amplified by laminar flow-assisted dendritic amplification (LFDA) using fluorescein isothiocyanate (FITC)-labeled streptavidin (F-SA) and biotinylated anti-streptavidin (B-anti-SA) as amplification reagents. To enhance the sensitivity of on-chip miRNA detection, the hybridization buffer solution was newly optimized with three main components-sodium dodecyl sulfate (SDS), formamide and dextran sulfate-that are known to strongly influence hybridization. An on-chip miRNA detection test in the newly optimized hybridization buffer (0.2% SDS, 5% formamide and 1% dextran sulfate) revealed dramatic increases in both the LFDA signal in the sample channel and the signal-to-background ratio (S/B ratio). Moreover, the LFDA signals in a blank reference channel remained low due to the suppression of non-specific bindings and hybridizations. By changing the hybridization buffer, we obtained an improved limit of detection (LOD) that was 0.045 pM (miRNA-196a) and 0.45 pM (miRNA-331), which are around 30- and 10-fold better than that of when control hybridization buffer was used. The improved performance of our miRNA detection system with short running time and high sensitivity could contribute to future research, including point-of-care diagnostic systems.

Evaluation of the formation of a junctional DNA nanostructure through annealing curve analysis

During the self-assembly of different numbers of oligonucleotides comprising junctional DNA nanostructures, a change in environmental variables (e.g., temperature or salt concentration) has a substantial influence on the final products. Further, distinctive annealing temperatures of oligonucleotides are observed depending on the state of hybridization. Here, we present an evaluation of the annealing characteristics of oligonucleotides for the formation of a simple junctional DNA nanostructure using an annealing curve analysis. This method may be useful for analyzing the formation of complex junctional DNA nanostructures.

Lateral flow microarrays: a novel platform for rapid nucleic acid detection based on miniaturized lateral flow chromatography

Widely used nucleic acid assays are poorly suited for field deployment where access to laboratory instrumentation is limited or unavailable. The need for field deployable nucleic acid detection demands inexpensive, facile systems without sacrificing information capacity or sensitivity. Here we describe a novel microarray platform capable of rapid, sensitive nucleic acid detection without specialized instrumentation. The approach is based on a miniaturized lateral flow device that makes use of hybridization-mediated target capture. The miniaturization of lateral flow nucleic acid detection provides multiple advantages over traditional lateral flow devices. Ten-microliter sample volumes reduce reagent consumption and yield analyte detection times, excluding sample preparation and amplification, of <120 s while providing sub-femtomole sensitivity. Moreover, the use of microarray technology increases the potential information capacity of lateral flow. Coupled with a hybridization-based detection scheme, the lateral flow microarray (LFM) enables sequence-specific detection, opening the door to highly multiplexed implementations for broad-range assays well suited for point-of-care and other field applications. The LFM system is demonstrated using an isothermal amplification strategy for detection of Bacillus anthracis, the etiologic agent of anthrax. RNA from as few as two B. anthracis cells was detected without thermocycling hardware or fluorescence detection systems.

Alterations on phosphodiesterase type 7 and 8 isozyme mRNA expression in Alzheimer's disease brains examined by in situ hybridization

Phosphodiesterases (PDEs) play a central role in signal transduction by regulating intracellular levels of cyclic AMP (cAMP) and cGMP. It has been suggested that cAMP pathways could be upregulated in Alzheimer's disease. By in situ hybridization histochemistry we have determined the expression pattern of two newly described cAMP-specific phosphodiesterases families, PDE7 and PDE8, in several brain areas in control subjects. The hybridization levels of PDE8A mRNA were very low in all brain areas examined. High PDE7B and PDE8B mRNA signal intensities were found in the hippocampal formation. PDE7A was found to be present in both neuronal and non-neuronal cell populations. When the expression of these isozymes in control brains was compared with that in Alzheimer's disease brains staged according to Braak and Braak (Acta Neuropathol. (Berl.) 82 (1991), 239), we found that PDE8B was the only isozyme showing a significant increase, in cortical areas and parts of the hippocampal formation, at Braak stages III-VI. Our results show that the expression of specific cAMP PDE isoforms is selectively regulated in Alzheimer's disease and associated with the stages of the disease. The availability of animal models of Alzheimer's disease and of new pharmacological tools such as selective PDE inhibitors will allow study of the therapeutic potential of the control of cAMP levels in AD.

Differences in chicken major histocompatibility complex (MHC) class Ialpha gene expression between Marek's disease-resistant and -susceptible MHC haplotypes

The expression of chicken major histocompatibility complex (MHC) class Ialpha genes was investigated in spleen cells from a panel of chickens with well-defined MHC haplotypes, and two class Ialpha transcripts of 1.9 and 1.5 kb were detected in various amounts. In BW1, B130 and B21, the two transcripts were almost equally expressed. In B2, B6, B12 and B19, the ratio between the two transcripts was 4 : 1, with the 1.9 kb transcript having the strongest expression. In B14 and B15, the 1.5 kb transcript was undetectable and the 1.9 kb transcript appeared to be exclusively expressed. Thus, haplotypes considered to have an MHC-determined resistance to Marek's disease (MD) had the highest relative amount of the 1.5 kb transcript, whereas haplotypes considered to be MD-susceptible had the lowest. In order to address a possible correlation between MHC-Ialpha transcriptional patterns and MD resistance, a larger animal material experimentally infected with MD virus (MDV) was examined. The expression of MHC class Ialpha genes was investigated in spleens as well as in other organs, 9 weeks post-infection (p.i.), from animals of the two MD-resistant haplotypes B21 and BW1 as well as from the MD-susceptible haplotype B19. In the spleen cells of infected animals, the relative amount of the 1.5 kb transcript in the haplotypes BW1 and B21 was shown to be significantly higher than that in B19. Interestingly, in infected BW1 and B21 animals, the relative amount of the 1.5 kb transcript was also significantly higher than that in healthy MHC-matched controls. In B19, no differences were detected between uninfected and infected animals. Furthermore, it was shown in BW1 and B21 that the two classical MHC-Ialpha genes located in the MHC region were both able to produce both mRNA transcripts. Hybridization experiments, using specific probes upstream and downstream of the polyadenylation signals in the 3' end of the MHC-Ialpha genes, demonstrated that alternate use of these signals is probably involved in the production of the two mRNA transcripts.

Phosphodiesterase type 4 isozymes expression in human brain examined by in situ hybridization histochemistry and[3H]rolipram binding autoradiography. Comparison with monkey and rat brain

We have examined the distribution of four different cyclic AMP-specific phosphodiesterase isozyme (PDE4A, PDE4B, PDE4C and PDE4D) mRNAs in the brain of different species by in situ hybridization histochemistry and by autoradiography with [3H]rolipram. We have compared the localization of each isozyme in human brain with that in rat and monkey brain. We have found that the four PDE4 isoforms display a differential expression pattern at both regional and cellular level in the three species. PDE4A, PDE4B and PDE4D are widely distributed in human brain, with the two latter appearing more abundant. In contrast, PDE4C in human brain, presents a more restricted distribution, limited to cortex, some thalamic nuclei and cerebellum. This is at variance with the distribution of PDE4C in rat brain, where it is found exclusively in olfactory bulb. In monkey brain, the highest expression for this isoform is found in the claustrum, and at lower levels in cortical areas and cerebellum. PDE4B presented a broad distribution, being expressed in both neuronal and non neuronal cell populations. In general, the distribution of binding sites visualized with [3H]rolipram correlated well with the expression of each PDE4 isozyme.

Antepartum glucocorticoid therapy suppresses human placental xenobiotic and steroid metabolizing enzymes

We investigated the effects of maternal gestational corticosteroid therapy on placental xenobiotic and steroid metabolizing enzymes at term in 20 glucocorticoid/betamethasone treated (with various doses) and control (n=10) women. A single dose of betamethasone (12 mg i.m. twice at a 24-h interval) was given to 15 mothers at risk of preterm delivery to prevent respiratory syndrome in their premature newborns. Five mothers were treated more than once. The gestation time in mothers receiving the glucocorticoid therapy varied from 22-38 gestational weeks. Compared with controls, a significant decrease in placental aromatase activity (53.6+/-18.0 pmol/mg/min versus 119+/-30 pmol/mg/min, P=0.0007) and placental CYP19 mRNA content (by 50 per cent ) was observed in mothers treated with glucocorticoids. Also the formation of androstenedione (13.2+/-8.1 pmol/mg/min, steroids versus 30.03+/-5.2 pmol/mg/min, controls, P< 0.001), using testosterone as the substrate, and 7-ethoxycoumarin O-deethylase (P< 0.05) and 7-ethoxyresorufin O-deethylase (P< 0.09) were slightly decreased in the glucocorticoid treated compared to control patients' values. The changes were not dependent on the number of treatments or the time between treatment and delivery. Our results demonstrate that even a single dose of glucocorticoid given to expectant mothers is associated with diminished placental steroid hormone and xenobiotic metabolizing enzymes at term. Further studies are needed to assess whether these changes affect the well-being of the fetus and its later development.

In situ hybridization analysis of immunoglobulin heavy chain variable gene expression with family specific oligonucleotide probes

We have developed an improved in situ hybridization (ISH) technique for the analysis of human immunoglobulin heavy chain variable (V(H)) gene family expression in suspensions of human B lymphocytes. Oligonucleotide probes specific for framework region (FR) consensus germline sequences for each of the seven human V(H) gene families were designed and hybridization conditions were developed to accommodate the greatest degree of V(H) gene variation, maximize the sensitivity of transcript detection, and assure the specificity of the technique. The hybridization parameters were rigorously characterized by Southern hybridization to a panel of 30 V(H) cDNA clones and by ISH to 17 B cell lines expressing characterized V(H) genes. Results obtained with ISH using V(H) gene family and isotype-specific gene probes correlated well with histochemical measures of Ig gene product expression. Profiles of cellular V(H) gene expression were generated for mitogen stimulated peripheral blood B lymphocytes from six normal subjects. When compared with estimates of frequency of V(H) genes in the human germline, the results were consistent with a random pattern of V(H) family utilization.

T-cell receptor variable region genes in cutaneous T-cell lymphomas

The genes encoding the T-cell receptor (TCR) variable beta (TCRBV) regions were studied in skin biopsy samples from 24 patients with cutaneous T-cell lymphomas (CTCL), i.e. mycosis fungoides (n = 7), Sézary syndrome (n = 4), lymphomatoid papulosis (n = 3) and large cell CTCL with (n = 3) or without (n = 7) CD30 expression. A panel of 24 primers specific for TCRBV families 1-24 was designed and applied to cDNA using a semiquantitative reverse transcriptase coupled polymerase chain reaction (PCR) method. Three patients showed restricted expression of a limited number (1-3) of TCRBV families. In the remaining patients, an average of 17 (range: 13-22) different families was expressed. All patients showed elevated (> 10%) expression of individual families significantly higher than that seen in normal blood lymphocytes, but no preferential usage of particular gene families was observed. Direct sequence analysis of more than 60 PCR products revealed clonal TCR transcripts in 18 patients. A single T-cell clone, constituting 9-100% (mean: 26%) of the TCRBV mRNA, was present in 12 patients; two T-cell clones, constituting 13-72% (mean: 21.5%) of the TCRBV mRNA, were present in five patients; and three T-cell clones, accounting for < 0.5-13% of the TCRBV mRNA, were present in one patient. In the remaining six patients, clonal TCR transcripts could not be identified. It is concluded that most CTCL contain both clonal and non-clonal (reactive) T cells, and that the latter cells are more numerous than anticipated. These cells may be engaged in tumour immune reactions, although prospective studies and/or serial investigations are needed to elucidate this issue fully.

Development of a rapid, nonradioactive, oligonucleotide-based assay for the detection of Setaria digitata

Setaria species are filarial parasites which inhabit the peritoneal cavity of cattle and other ungulates. The parasite is generally considered to be nonpathogenic in its natural hosts, but the transmission of the infective larvae through mosquito vectors to its abnormal hosts (goats, sheep, or horses) can result in a serious and often fatal neuropathological disorder commonly referred to as cerebrospinal nematodiasis. We have previously described the cloning and characterization of a repetitive DNA sequence of Setaria digitata that could be used as a diagnostic probe to detect the parasite in host and vector populations. Here we report the development of a rapid nonradioactive hybridization assay using an oligonucleotide probe based on the above cloned repetitive sequence.

Intrauterine transmission of human T-cell leukemia virus type I in rats

To analyze intrauterine transmission, MT-2 cells, a human T-cell line producing human T-cell leukemia virus type I (HTLV-I), were injected into eight pregnant F344 rats, and cesarean section was performed at day 23 of pregnancy. HTLV-I provirus was detected by PCR in the liver and spleen taken from one of the eight fetuses. Moreover, 71 offspring were delivered by cesarean section from the remaining seven dams and fostered by seven normal rats. HTLV-I provirus was detected in peripheral blood mononuclear cells in 2 of the 71 offspring 4 weeks after cesarean section. These results indicate for the first time the intrauterine transmission of HTLV-I. To confirm the postnatal transmission, MT-2 cells were injected into a dam within 24 h after delivery, and six offspring were fostered by this dam. HTLV-I provirus was detected in peripheral blood mononuclear cells of all six offspring. This animal model may be useful for analysis and prevention of mother-to-child transmission of HTLV-I.

High incidence of HAM/TSP-like symptoms in WKA rats after administration of human T-cell leukemia virus type 1-producing cells

We demonstrate a significantly high incidence of human T-cell leukemia virus type 1 (HTLV-1)-associated myelopathy (HAM)-or tropical spastic paraparesis (TSP)-like symptoms in WKA rats after injection with HTLV-1-producing MT-2 cells, while no symptoms were observed in F344 rats injected with MT-2 cells or in control WKA rats. Five of the eight (63%) WKA rats injected with MT-2 cells showed HAM/TSP-like paraparesis at 105 weeks of age, but none of seven MT-2-injected F344 rats or eight control WKA rats showed symptoms. This high incidence of HAM/TSP-like symptoms in WKA rats was statistically significant (P < 0.05). Six of the eight (75%) WKA rats injected with MT-2 cells showed HAM/TSP-like paraparesis at 108 weeks of age. HAM/TSP-like symptoms were also observed in one of the two WKA rats injected with HTLV-1-producing Ra-1 cells at 128 weeks of age. HTLV-1 provirus was detected in peripheral blood mononuclear cells in both WKA and F344 rats. The provirus was detected in the spinal cords of the HAM/TSP-like WKA rats that had severe neuropathological changes. WKA and F344 rats showed no significant difference in antibody response against HTLV-1 Gag antigen. However, the antibody response against the C-terminal half of gp46 HTLV-1 envelope protein was lower in WKA rats than in F344 rats. Pathological analysis of the HAM/TSP-like rats showed degeneration of the white matter of the spinal cord and peripheral nerves. These findings suggest that both the genetic background of the host and HTLV-1 infection are important in neuropathogenesis of HAM/TSP-like paraparesis in rats.

Expression and function of nerve growth factor and nerve growth factor receptor on cultured keratinocytes

Keratinocytes, a key cellular component both for homeostasis and pathophysiologic processes of the skin, secrete a number of cytokines and are stimulated by several growth factors. Nerve growth factor (NGF) is synthesized in the skin and basal keratinocytes express the low-affinity nerve growth factor receptor (NGF-R). We present evidence that normal human keratinocytes in culture express the low- and the high-affinity NGF-R both at the mRNA level, as determined by reverse-transcription polymerase chain reaction and at the protein level, as shown by cytofluorimetric analysis. NGF significantly stimulates the proliferation of normal human keratinocytes in culture in a dose-dependent manner. This effect can be prevented by the addition of both an anti-NGF neutralizing antibody and a high-affinity NGF-R (trk) specific inhibitor, the natural alkaloid K252a. By contrast, keratinocyte proliferation is not inhibited by an anti-low-affinity NGF-R monoclonal antibody, thus suggesting that NGF effect on human keratinocytes is mediated by the high-affinity NGF-R. Moreover, NGF mRNA is expressed in normal human keratinocytes and NGF is secreted by keratinocytes in increasing amounts during growth, as detected by enzyme-linked immunosorbent assay. These results suggest that NGF could act as a cytokine in human skin and take part in disorders of keratinocyte proliferation.

A growth hormone pseudogene in the salmon genome

Representatives of the fish family Salmonidae were reported to possess two nonallelic growth hormone (GH)-encoding genes. In addition to those, we found a third GH-like sequence in a chum salmon genomic DNA library. A number of point mutations and large deletions abolished the possibility of expressing this sequence, showing that the chum salmon genomic DNA contains a GH pseudogene besides functional GH genes.

Expression of acetylcholinesterase messenger RNA in human brain: an in situ hybridization study

The distribution of messenger RNA coding for acetylcholinesterase was studied in human post mortem brain and rhesus monkey by in situ hybridization histochemistry and compared to the distribution of acetylcholinesterase activity. Acetylcholinesterase messenger RNA had--similar to acetylcholinesterase enzymatic activity--a widespread distribution in human bain. Acetylcholinesterase messenger RNA positive cells corresponded to perikarya rich in acetylcholinesterase activity in most but not all regions. Examples for mismatches included the inferior olive and human cerebellar cortex. The presence of hybridization signals in cerebral cortex and an enrichment in layer III and V of most isocortical areas confirmed that perikaryal acetylcholinesterase in cerebral cortex is of postsynaptic origin and not derived from cholinergic projections. In striatum the expression of high levels of acetylcholinesterase messenger RNA was restricted to a small population of large striatal neurons. In addition, low levels of expression were found in most medium sized striatal neurons. Cholinergic neurons tended to express high levels of acetylcholinesterase messenger RNA whereas in cholinoceptive neurons the levels were moderate to low. However, some noncholinergic neurons like dopaminergic cells in substantia nigra, noradrenergic cells in locus coeruleus, serotoninergic cells in raphé dorsalis, GABAergic cells in thalamic reticular nucleus, granular cells in cerebellar cortex and pontine relay neurons expressed levels comparable to cholinergic neurons in basal forebrain. It is suggested that neurons expressing high levels of acetylcholinesterase messenger RNA may synthesize acetylcholinesterase for axonal transport whereas neurons with an expression of acetylcholinesterase confined to somatodendritic regions tend to contain lower levels of acetylcholinesterase messenger RNA.

Tropoelastin gene expression in the developing vascular system of the chicken: an in situ hybridization study

Temporal and spatial patterns in the accumulation of Tropoelastin (TE) mRNA during development of the chick embryo were established by in situ hybridization. Radiolabeled oligonucleotide probes of high specific activity were hybridized to serial sections of the cardiovascular system from embryonic day 3.5 (ED 3.5) to ED 19. Tropoelastin mRNA was observed as early as ED 3.5 in the dorsal part of the arterial trunk. During septation varying levels of TE mRNA were seen in the pulmonary trunk, the aorta and the aorticopulmonary septum. Thereafter TE mRNA levels increased up to ED 12, and the appearance of message was distributed distally in the walls of developing arteries. From ED 4.5 on, we found a decreasing proximo-distal gradient of the hybridization signal along the trunks and later along the main arteries (longitudinal gradient), and a radial gradient through the arterial vessel wall with the highest levels of TE mRNA in the outer layers of the media. Both gradients persisted in all major arterial vessels except in the proximal systemic and pulmonary trunks, where the original radial gradient was inverted or locally bimodal during the second half of development. The valvular region of aortic and pulmonary trunks showed particularly striking patterns of TE mRNA distribution, notably a prominent label on the endothelial cell layer on aortic and pulmonary valves. Outside the cardiovascular system, TE mRNA was mainly present in prochondral or perichondral cells in trachea and growing skeleton, and in the gap of growing joints. In kidney or nephric primordia, TE mRNA was only detectable in the wall of renal arteries. A hybridization signal was observed on mesenchyme of pulmonary septae at ED 16. Our results suggest a complex regulation of elastin gene expression during development, particularly within the proximal regions of the large arterial vessels.

Inhibition of c-fes expression by an antisense oligomer causes apoptosis of HL60 cells induced to granulocytic differentiation

The c-fes protooncogene is expressed at high levels in the terminal stages of granulocytic differentiation, but so far no definite function has been attributed to the product of this oncogene. To tackle this problem, the c-fes protooncogene expression has been inhibited in HL60 cells, and fresh leukemic promyelocytes of acute promyelocytic leukemia have been induced to differentiate with retinoic acid (RA) and dimethylsulfoxide (DMSO). Inhibition was obtained by incubating the cells with a specific c-fes antisense oligodeoxynucleotide. It was observed that the cells, rather than differentiating, underwent premature cell death showing the morphological and molecular characteristics of apoptosis. This process was inhibited by granulocyte and granulocyte/macrophage colony-stimulating factor, but not by interleukin 3 (IL-3), IL-6, or stem cell factor. Our present results demonstrate that the loss of cell viability that occurs during the in vitro differentiation of myeloid cells, after the complete inhibition of the c-fes gene product and treatment with RA-DMSO, is due to activation of programmed cell death. It is concluded that a possible role of the c-fes gene product is to exert an antiapoptotic effect during granulocytic differentiation.

Overexpression of c-kit in a leukemic cell population carrying a trisomy 4 and its relationship with the proliferative capacity

The expression of c-kit and its ligand, the stem cell factor (SCF), was studied in five cases of acute myeloid leukemia. One of these had a trisomy of chromosome 4, where the c-kit oncogene is located. In this case, the c-kit oncogene was overexpressed, but matched by a low expression of its ligand, SCF. The molecular evaluation of the growth rate by c-myc and the histone H3 expression indicated that the growth fraction of this cell population was very low. In one of the other leukemic cell populations studied, characterized by a low expression of c-kit and an elevated expression of the SCF, the growth fraction was also very low. Our results suggest that at least for some receptor oncogenes, the simple overexpression cannot be taken as an indication that the oncogene is involved in the deregulation of cell proliferation.

Expression of interleukins 1, 3, 6, stem cell factor and their receptors in acute leukemia blast cells and in normal peripheral lymphocytes and monocytes

Reverse transcriptase-polymerase chain reaction amplification (RT-PCR) and Southern blot analysis were used to evaluate ligand and receptor expression of interleukin 1 alpha (IL-1 alpha), interleukin 3 (IL-3), interleukin 6 (IL-6) and stem cell factor (SCF) in peripheral blood lymphocytes and monocytes and in several acute leukemia blast cell populations. Resting peripheral lymphocytes and monocytes expressed both ligand and receptor of the four cytokines at considerable levels. The leukemic blast cells of the M1-M4 phenotypes are characterized by almost complete lack of expression of IL-1 alpha, IL-3 and IL-6 and the constant and usually high expression of SCF. On the other hand, these myeloid blast cells express generally high levels of the four cytokine receptors. The data suggest that the regulation of the expression of IL-1 alpha, IL-3 and IL-6, at least in our limited number of leukemic cell populations studied, is independent of that of SCF. The results indicate that, at least in most of the leukemic myeloid blasts cells, the expression of SCF and its receptor, the c-kit oncogene, may permit an autocrine regulation of cell cycling.

Effect of pyrazole, cobalt and phenobarbital on mouse liver cytochrome P-450 2a-4/5 (Cyp2a-4/5) expression

Pyrazole, cobalt and phenobarbital increase the activity of coumarin 7-hydroxylase (COH) in mouse liver. To study the mechanism of this increase, we measured the expression of the cytochrome P-450 2a-4/5 (Cyp2a-4/5) complex, which mediates testosterone 15 alpha-hydroxylase and COH activities, as a function of dose and time after the treatment of C57BL/6 (B6) and DBA/2 (D2) male mice with the inducers. COH activity and Cyp2a-4/5 steady-state mRNA levels were increased in both strains in response to the inducers. No marked effect occurred with testosterone 15 alpha-hydroxylase or activities associated with Cyp1a-1 or Cyp2e-1. A 2-7-fold increase in response to the inducers was seen in the amount of P-450Coh (cytochrome P-450 isoenzyme catalysing coumarin 7-hydroxylation) protein in Western immunoblots. PCR amplification of a 1 kb region in Cyp2a-4/5-mRNA-derived cDNA, followed by cutting at the diagnostic PstI site, showed that most of the steady-state mRNA consisted of Cyp2a-5, which is also the form most affected by pyrazole. Nuclear run-off analysis revealed no increase in the transcription rate of Cyp2a-4/5 after pyrazole or cobalt treatment, whereas a 2-3-fold increase occurred after phenobarbital pretreatment in B6 mice. Together with previous reports [Aida & Negishi (1991) Biochemistry 30, 8041-8045], the current data suggest that both pyrazole and cobalt increase COH catalytic activity by affecting Cyp2a-5 by post-transcriptional mechanisms in mice.

Passive mechanical stretch releases atrial natriuretic peptide from rat ventricular myocardium

Ventricular hypertrophy is characterized by augmentation of synthesis, storage, and release of atrial natriuretic peptide (ANP) from ventricular tissue, but the physiological stimulus for ANP release from ventricles is not known. We determined the effect of graded, passive myocardial stretch on ANP release in isolated, arrested, perfused heart preparations after removal of the atria in 13-20-month-old Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). By this age, ANP gene expression was increased in the hypertrophic ventricular cells of SHR, as reflected by elevated levels of immunoreactive ANP and ANP mRNA and the increased ANP secretion (SHR, 93 +/- 14 pg/ml, n = 22; WKY rats, 22 +/- 2 pg/ml, n = 20; p less than 0.001) from perfused ventricles after removal of the atria. The release of ANP from ventricles was examined at two levels of left ventricular pressure by increasing the volume of the intraventricular balloon for 10 minutes. Stretching of the ventricles produced a rapid but transient increase in ANP secretion. As left ventricular pressure rose from 0 to 14 and 26 mm Hg in WKY rats and from 0 to 13 and 27 mm Hg in SHR, increases in ANP release into the perfusate of 1.4 +/- 0.1-fold and 1.5 +/- 0.2-fold (p less than 0.05) in WKY rats and 1.1 +/- 0.1-fold and 1.6 +/- 0.2-fold (p less than 0.05) in SHR, respectively, were observed. There was a highly significant correlation between the left ventricular pressure level and the maximal concentration of ANP in the perfusate during stretching (p less than 0.001, r = 0.59, n = 42), as well as between the maximal ANP concentrations in perfusate during stretching and the ventricular weight/body weight ratios of the corresponding animals (r = 0.38, p less than 0.05, n = 42). High performance liquid chromatographic analysis revealed that the ventricles both before and during stretch primarily released the processed, active, 28-amino acid ANP-like peptide into the perfusate. These results indicate that stretching is a direct stimulus for ventricular ANP release and show that ANP is also a ventricular hormone.

MHC Class II Beta-Chain Expression in the Rainbow Trout

A cDNA clone corresponding to the MHC class II beta-chain of the rainbow trout (Oncorhynchus mykiss) has been isolated and used in restriction fragment length polymorphism (RFLP) studies in a family of full siblings of rainbow trout. A very simple RFLP pattern was detected, suggesting segregation of a homozygote AA genotype and a heterozygote AB genotype. The MHC class II beta-chain of the rainbow trout seems to be transcribed in the same type of cells as class II genes of higher vertebrates even though the cDNA clone recognizes atypical messenger sizes of 2.2 kb and 3.6 kb in the analysed family. Surprisingly the transcripts seem to be allele-specific for the assigned genotypes.

Muscarinic M2 receptor mRNA expression and receptor binding in cholinergic and non-cholinergic cells in the rat brain: a correlative study using in situ hybridization histochemistry and receptor autoradiography

The goal of the present study was to identify the cells containing mRNA coding for the m2 subtype of muscarinic cholinergic receptors in the rat brain. In situ hybridization histochemistry was used, with oligonucleotides as hybridization probes. The distribution of cholinergic cells was examined in consecutive sections with probes complementary to choline acetyltransferase mRNA. Furthermore, the microscopic distribution of muscarinic cholinergic binding sites was examined with a non-selective ligand ([3H]N-methylscopolamine) and with ligands proposed to be M1-selective ([3H]pirenzepine) or M2-selective ([3H]oxotremorine-M). The majority of choline acetyltransferase mRNA-rich (i.e. cholinergic) cell groups (medial septum-diagonal band complex, nucleus basalis, pedunculopontine and laterodorsal tegmental nuclei, nucleus parabigeminalis, several motor nuclei of the brainstem, motoneurons of the spinal cord), also contained m2 mRNA, strongly suggesting that at least a fraction of these receptors may be presynaptic autoreceptors. A few groups of cholinergic cells were an exception to this fact: the medial habenula and some cranial nerve nuclei (principal oculomotor, trochlear, abducens, dorsal motor nucleus of the vagus). Furthermore, m2 mRNA was not restricted to cholinergic cells but was also present in many other cells throughout the rat brain. The distribution of m2 mRNA was in good, although not complete, agreement with that of binding sites for the M2 preferential agonist [3H]oxotremorine-M, but not with [3H]pirenzepine binding sites. Regions where the presence of [3H]oxotremorine-M binding sites was not correlated with that of m2 mRNA are the caudate-putamen, nucleus accumbens, olfactory tubercle and islands of Calleja. The present results strongly suggest that the M2 receptor is expressed by a majority of cholinergic cells, where it probably plays a role as autoreceptor. However, many non-cholinergic neurons also express this receptor, which would be, presumably, postsynaptically located. Finally, comparison between the distribution of m2 mRNA and that of the proposed M2-selective ligand [3H]oxotremorine-M indicates that this ligand, in addition to M2 receptors, may also recognize in certain brain areas other muscarinic receptor populations, particularly M4.

HPV in full thickness cervical biopsies: high prevalence in CIN 2 and CIN 3 detected by a sensitive PCR method

A new type-specific, sensitive, non-radioactive assay is described for the detection of human papillomavirus (HPV) DNA in tissues. Sequences within the E6 gene were amplified by the polymerase chain reaction (PCR), using primer pairs which clearly distinguish HPV types, including those with close sequence homology such as 6b and 11. The amplified DNA products were identified by non-radioactive oligonucleotide hybridization and restriction endonuclease mapping, and the method was sufficiently sensitive to detect between 3 and 5 SiHa cells (each containing 1-2 copies of HPV 16 DNA) amongst 10,000 non-HPV-containing cells. Frozen and archival paraffin sections were equally acceptable substrates for the reaction. The assay was applied to frozen sections of full thickness cervical epithelium from 60 cases of cervical intraepithelial neoplasia (CIN) and 24 normal cervical controls. HPV DNA was detected in 60 per cent of cases of CIN 3 and CIN 2, in 25 per cent of cases of CIN 1, and in none of the normal controls. Prevalence of HPV 16 was similar (approximately 50 per cent) in both CIN 2 and CIN 3, and in the whole series HPV 16 was almost five-fold more common than HPV 18. Low-risk HPV types were present in 5 per cent of CIN 1, but 0 per cent of CIN 2 and CIN 3 biopsies. The data emphasize the biological similarity of CIN 2 and CIN 3 lesions, and their divergence from CIN 1.

Infection of rats with HTLV-1: a small-animal model for HTLV-1 carriers

A human T-cell line producing human T-cell leukemia virus type I (HTLV-I), MT-2, was injected intravenously into female F344 rats aged 5 weeks to make HTLV-I carrier rats. Antibody against HTLV-I was detected at the 5th week after MT-2 injection, and its titer reached a high plateau which continued from the 15th to the 27th week. The antibodies were against p19, p24, p28 and p53 of HTLV-I antigens from MT-2 cells. The gag, pX and LTR nucleotide sequences of HTLV-I provirus were demonstrated by using polymerase chain reaction (PCR) in the peripheral-blood mononuclear cells of 3 rats at the 44th week and 2 at the 66th to 68th week out of 8 F344 rats injected with MT-2 cells. Quantification of the HTLV-I proviral sequence revealed that 30 to 60 molecules were present in 10(5) peripheral-blood mononuclear cells, indicating that the rats were chronically infected with HTLV-I. HTLV-I-infected rats could serve as a small-animal model for studying the pathophysiological state of HTLV-I carriers and also that of HTLV-I infection on various HTLV-I-related diseases, including adult T-cell leukemia and HTLV-I-associated myelopathy.

The use of oligodeoxynucleotide probes in chaotrope-based hybridization solutions

Hybridization solutions containing chaotropes may be used to modulate the thermal stability (Tm or Td) of oligodeoxynucleotide (ODN) duplexes or hybrids over a 90 degrees C range. Modulation of Td allows formulation of hybridization solutions that permit ambient temperature hybridization using most combinations of probe length, probe composition, target type, and facilitates development of convenient and rapid assay formats. The conditions required to achieve ODN duplex fidelity, and optimal yields of hybridized product, are described for trichloroacetate, thiocyanate, guanidinium salts and other chaotropic salts. The effects of different solid supports on Td are described. Also, a method is presented that uses chaotropic compounds to reduce background arising from signal ODN probes in a sandwich assay hybridization format.

Analysis of unknown DNA sequences by polymerase chain reaction (PCR) using a single specific primer and a standardized adaptor

A new procedure for the PCR amplification of unknown DNA sequences adjacent to a known sequence is described. The required but not readily available second primer sequence in the unknown DNA sequence is obtained by creating an overhanging restriction site in the unknown sequence to which a double-stranded oligonucleotide adaptor of known sequence is ligated.

Intervening sequences (IVSs) in the 23S ribosomal RNA genes of pathogenic Yersinia enterocolitica strains. The IVSs in Y. enterocolitica and Salmonella typhimurium have a common origin

The 23S ribosomal RNA (rRNA) was shown to be in two fragments in pathogenic Yersinia enterocolitica. The cleavage site in the structural gene of the 23S rRNA was occupied by an intervening sequence (IVS) of about 100 nucleotides, analogous to IVSs found in salmonellae (Burgin et al., 1990). Nucleotide sequences of IVSs of several Y. enterocolitica strains revealed that the IVSs of the highly virulent Y. enterocolitica serotypes strains, and the IVS of Salmonella typhimurium were about 90% similar. On the other hand, the IVSs of the highly and the poorly virulent Y. enterocolitica serotypes were only about 60% similar. These results give the impression that at some point during the IVS evolution, the highly virulent Y. enterocolitica and S. typhimurium both received their IVSs at about the same time from the same source, and that the poorly virulent serotypes received their IVSs earlier. We also found that strain LB5010, derived by extended mutagenization of S. typhimurium LT2, had lost the IVSs originally present in LT2, and that this loss had created a new 'hairpin loop' which substituted for the original 'hairpin loop'.

Effect of phorbol ester on the release of atrial natriuretic peptide from the hypertrophied rat myocardium

1. To determine the cellular mechanisms of atrial natriuretic peptide (ANP) release from ventricular cardiomyocytes, the secretory and the cardiac effects of a phorbol ester, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), known to stimulate protein kinase C activity in heart cells, were studied in isolated, perfused heart preparations from 2- and 21-month-old Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. TPA was added to the perfusion fluid for 30 min at a concentration of 46 nM after removal of atrial tissue. Additionally, atrial and ventricular levels of immunoreactive ANP (IR-ANP) and ANP mRNA, the distribution of ANP within ventricles as well as the relative contribution of atria and ventricles in the release of ANP were studied. 2. Ventricular hypertrophy that gradually developed in hypertensive rats resulted in remarkable augmentation of ANP gene expression, as reflected by elevated levels of immunoreactive ANP and ANP mRNA. The total amount of IR-ANP in the ventricles of the SHR rats increased 41 fold and ANP mRNA levels 12.9 fold from the age of 2 to 21 months. At the age of 21 months, levels of IR-ANP and ANP mRNA in the ventricles of SHR rats were 5.4 fold and 3.7 fold higher, respectively, than in the normotensive WKY rats. Immunohistochemical studies demonstrated ANP granules within the hypertrophic ventricles of the old SHR rats, but not within normal ventricular tissue. 3. In isolated perfused heart preparations, the severely hypertrophied ventricular tissue of SHR rats after atrialectomy secreted more ANP into the perfusate than did the control hearts. Interestingly, the ANP release from the hypertrophied ventricles of the old SHR rats increased considerably (from 413 + 30 to the maximum of 623 + 75 pgml-1, F = 10.8, P < 0.001, two-way analysis of variance), whereas only a small increase was seen in old WKY rats and no effect was observed in young animals of either strain. When intact rat hearts (without atrialectomy) were used, infusion of phorbol ester also increased the ANP secretion into the perfusate in young animals. 4. Our present results indicate that the phorbol ester TPA increases the release of ANP from the hypertrophied, but not from normal rat myocardium. Thus, hypertrophied rat ventricular myocytes appear to possess the cellular mechanisms necessary to secrete ANP by a regulated pathway. The results further suggest that protein kinase C activity may be involved in the the regulation of ANP secretion from ventricular cells, as has been shown earlier for atrial myocytes.

Localization in situ of specific mRNA using thymine-thymine dimerized DNA probes. Sensitive and reliable non-radioactive in situ hybridization

In situ hybridization has been recognized as a powerful technique for localizing specific nucleic acids such as mRNA and viral DNA in individual cells. For in situ hybridization, the use of a non-radioactive probe is considered superior to that of a radioactive one from viewpoints of resolution, probe stability and personal safety. Although various non-radioactive labels are currently available, some interfere with the formation of hybrids and some increase steric hindrance and prevent penetration of the labeled nucleic acid probe into cells and tissues. Recently, we have developed a method using thymine-thymine (T-T) dimerized DNA as a non-radioactive probe. This is simple to make, since it dose not require separation of labeled DNA from unreacted labeling compounds, and T-T dimer will not alter the chemical and physical nature of the probe. In this paper, we describe the tissue processing procedures that are suited for the T-T dimerized DNA probes, and the recent new findings on methodological aspects, particularly the use of synthetic oligodeoxynucleotide probes.

Polymerase chain reaction for probe synthesis and for direct amplification in detection of bovine coronavirus

The polymerase chain reaction (PCR) was used to synthesize ds and ss probes for the detection of bovine coronavirus (BCV) using recombinant plasmids as template molecules. The ds probes detected a minimum of about 2 X 10(5) viral genomes after exposure for 1 h, a detection limit similar to nick-translated probes after exposure of the films for 60 h. More than 8 h exposure to blots probed with these ds probes resulted in complete darkening of the film. The ss probes, synthesized by asymmetric PCR on linearized plasmids, permitted the detection of 5 X 10(4) genomes, which equalled the capacity of random-primed probes. Prolonged exposure did not increase the background as in case of ds PCR-probed blots. Probes, synthesized by asymmetric PCR and random-priming were labeled to similar specific activities and were better in terms of sensitivity and detectability as opposed to nick-translated probes. However, the specificity of detection with ss probes as to random primed probes was increased further. About 10 viral genomes, after fragment-specific amplification by PCR, were detected by agarose-gel analysis. PCR-probe synthesis was simple, highly reproducible, and allowed the synthesis of probes for specific fragments.

The extensin gene family in oilseed rape (Brassica napus L.): characterisation of sequences of representative members of the family

A family of cross-hybridising cDNA clones has been isolated from a cDNA library produced with poly(A)+ RNA from the roots of oilseed-rape (Brassica napus L.). The clones were selected as abundantly expressed in root by differential screening of the root cDNA library with cDNA probes prepared from root, green leaf, etiolated leaf and developing seed. mRNA species corresponding to the selected abundant clones were expressed in roots at levels of at least 400 times those in other organs, as shown by Northern blot analysis and RNase protection assays. Complete nucleotide sequence determination of the cDNA clones showed that they encoded proteins homologous to carrot extensin and were the products of at least three different genes. An extensin gene, designated extA, was obtained from an oilseed rape (B. napus L.) genomic library screened with a cDNA species encoding a protein expressed abundantly in roots. The gene is a member of a multigene family, consisting of about 3 members per haploid genome with strong homology to the probe, and a further 20 or so members with weaker homology. The isolated gene, although not identical to the cDNA probe, was also found to be specifically expressed in roots, and was transcribed into a mRNA species approximately 1,300 nucleotides in size. A single transcription start was identified by S1 mapping. The complete nucleotide sequence of the extA gene and its flanking regions has been determined and shown to encode a protein homologous to carrot and tomato extensins.

Applications of magnetic beads with covalently attached oligonucleotides in hybridization: isolation and detection of specific measles virus mRNA from a crude cell lysate

A novel, rapid, one-step isolation procedure utilizing oligonucleotides end-attached to magnetic beads (Dynabeads) has been developed. The beads and their captured target nucleic acids were separated after 2 h from the hybridization solution using an external magnet. This procedure was used to isolate measles virus hemagglutinin (H) mRNA from infected cells dissolved in 5 M guanidine thiocyanate. The yield of the specific, undegraded H-mRNA was found to be near the estimated total amount of H-mRNA present in the cells. The magnetic beads were also used for detection of measles virus H-mRNA in a crude cell lysate by sandwich hybridization. The experimental detection limit was 630 amol H-mRNA.

Adrenal cortex contributes to the regulation of NaCl-stimulated ANP release in the rat

The present study documents the effects of hypophysectomy and the effects of dexamethasone substitution on the NaCl-stimulated release and on the basal secretion rates of ANP from the rat atria in vitro. We also measured the concentration of mRNA in the atria after hypophysectomy. Rats (n = 12) were subjected to hypophysectomy by a parapharyngeal approach. One group of rats (n = 6) received dexamethasone 0.2 mg s.c. daily for 4 weeks, while the other group was left unsubstituted. After 4 weeks, the atrial block (n = 10) was excised, placed in an organ bath (field stimulation 4 s-1, 20 V, 1 ms; resting tension = 5 mN) and superfused (7 ml min-1) either with a physiological buffer solution (295 mosmol kg-1) or with a hyperosmotic NaCl solution (330 mosmol kg-1). The atria from the hypophysectomized rats did not respond to the stimulus: the concentration of ANP in the 1-min samples of the perfusate was under 100 pg ml-1. Dexamethasone treatment significantly (P less than 0.05) increased the ANP concentration to a maximum of 165 +/- 17 (mean +/- SEM) pg ml-1 during the superfusion while the control concentration was 110 +/- 19 pg ml-1. The ANP mRNA/18 S RNA ratios did not differ between the atria of hypophysectomized and control rats. In conclusion, glucocorticoids are required in the stimulus-induced release of ANP and the impaired release of ANP after hypophysectomy does not depend on an impaired synthesis of ANP.

The effect of acute haloperidol treatment on brain proneurotensin mRNA: in situ hybridization analyses using a novel fluorescence detection procedure

These studies describe the normal anatomical distribution of neurons containing the mRNA coding for neurotensin (proneurotensin/neuromedin N) in the rat forebrain and midbrain and examine how that distribution is altered by acute administration of the dopamine antagonist haloperidol. A novel fluorescence detection method was developed and employed with biotinylated oligonucleotides to permit the rapid, sensitive visualization of in situ hybridization. The hybridization was temperature-sensitive, eliminated by ribonuclease, and co-localized in neurotensin-immunoreactive perikarya in the midbrain. In the forebrain of control rats, proneurotensin mRNA-containing neurons were found in the dorsomedial and ventrolateral caudate/putamen, in the nucleus accumbens, in the ventral striatum including the olfactory tubercles, and in the septal nuclei. Haloperidol induced significant increases in the frequencies and distributions of hybridization-positive neurons in the striatum and septal nuclei. In the midbrain, the highest frequency of hybridization-positive neurons occurred in the substantia nigra and the superior colliculus. Prominent populations were also present in the dorsal and ventral periaqueductal gray, the oculomotor region, and the medial longitudinal fasciculus. Less prominent were populations of neurons in the dorsomedial deep mesencephalic nuclei and the ventral tegmental area. Haloperidol induced only modest increases in the frequency of pro-neurotensin mRNA-containing neurons in the ventral tegmental area, and had no effects elsewhere in the midbrain. These results show that the fluorescent detection techniques used in this analysis provide a very rapid, reliable method for localizing hybridized mRNA in the rat brain. This study also suggests that a subpopulation of striatal neurons begin to express proneurotensin mRNA in response to haloperidol treatment. This effect of haloperidol on striatal neurons contrasts with results from additional studies of enkephalin mRNA in the striatum, suggesting that the mechanisms of haloperidol stimulation may differ between neurotensin and enkephalin-containing neurons.

Release of atrial natriuretic peptide from rat myocardium in vitro: effect of minoxidil-induced hypertrophy

1. Ventricular hypertrophy is characterized by stimulation of ventricular synthesis of atrial natriuretic peptide (ANP). To examine the role of ventricular ANP levels in the secretion of ANP into the circulation, atrial and ventricular levels of immunoreactive-ANP (IR-ANP) as well as ANP messenger RNA (mRNA), and the release of IR-ANP from isolated perfused hearts, both before and after atrialectomy, were measured simultaneously in control and minoxidil-treated Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. 2. IR-ANP levels in the ventricles of untreated, 12 month-old SHR with severe ventricular hypertrophy were increased when compared to age-matched WKY rats. Minoxidil treatment for 8 weeks in both strains resulted in a decrease in mean arterial pressure and increases in ventricular weight to body weight ratios, plasma IR-ANP concentrations (in WKY from 133 +/- 20 to 281 +/- 34 pg ml-1, P less than 0.01; in SHR from 184 +/- 38 to 339 +/- 61 pg ml-1, P less than 0.05), and in ventricular IR-ANP contents (in WKY: 53%; in SHR: 41%). A highly significant correlation was found between ventricular IR-ANP content and ventricular weight to body weight ratio (r = 0.59, P less than 0.001, n = 26). 3. When studied in vitro, in isolated perfused heart preparations, the hypertrophied ventricular tissue after atrialectomy secreted more ANP into the perfusate than ventricles of the control hearts; ventricles contributed 28%, 22%, 18% and 15% of the total ANP release to perfusate in the minoxidil-treated SHR, control SHR, minoxidil-treated WKY and control WKY, respectively. A significant correlation was found between the IR-ANP release from ventricles and ventricular weight to body weight ratio (r = 0.56, P < 0.01, n = 24). 4. These studies demonstrate that the ventricles contribute substantially to the circulating level of ANP, and that the amount released depends on the degree of ventricular hypertrophy.

Southern blot analysis with synthetic oligonucleotides. Application to prostatic protein genes

1. An ethanol precipitation procedure was developed to purify radiolabeled DNA and oligonucleotide probes to be used in Southern blots. 2. The radiolabeled probes produced strong hybridization signals on a clear background on Southern blot analysis of single gene copies even after 5 days of exposure on X-ray films. 3. An oligonucleotide probe complementary to human glandular kallikrein-1 coding region (amino acids 161-167) detected a single DNA fragment after digestion with Bam H1, Hind III or Pst 1. 4. Another oligonucleotide probe coding for the same region of human prostate-specific antigen detected 3 DNA fragments on Southern blots by contrast to a 1.5 kb full length cDNA probe which detected the presence of only one strong hybridization signal. 5. Oligonucleotide probes appear to be excellent tools for gene mapping. Their sensitivity, specificity and limitations can be compared to the one of monoclonal antibodies used in epitope mapping of proteins.

Characterization of a cDNA encoding a new member of the glucocorticoid-responsive cytochromes P450 in human liver

Adult human liver contains a form of cytochrome P450, termed HLp, that resembles the glucocorticoid-inducible cytochrome P450p in rat liver in its structure, function, and regulation and catalyzes the oxidation of such clinically important substrates as cyclosporin, nifedipine, erythromycin, and midazolam. Recent evidence, however, suggests that HLp may represent two or more closely related forms of cytochromes P450, one of which is termed P450nf. To search for additional members of the Class III human subfamily of HLp related genes, we screened a human liver cDNA library cloned in phage vector lambda gt11 with oligonucleotides and with a cDNA fragment related to HLp. We isolated a full-length cDNA (1709 nucleotides) encoding a new form of human cytochrome P450 termed HLp2. Analysis of HLp2 cDNA predicted a protein of 502 amino acids, weighing 57,294 Da 83% similar to HLp. HLp2 appears to represent a distinct gene as judged by partial sequence analysis of a cloned human gene and by hybridizations of Southern blots, under conditions of varying stringency, with a 3'-portion of HLp cDNA and with an oligonucleotide specific for HLp2. Northern blot analysis revealed that HLp/P450nf was present in all samples of liver mRNA from adult patients not treated with inducers of HLp, whereas HLp2 mRNA was undetectable in more than two-thirds. Human fetal liver RNA contained mRNA species 2.1 and 1.9 kb which hybridized with an HLp2 oligonucleotide. We conclude that HLp2 represents a third member of the Class III glucocorticoid-responsive gene family that is expressed in both fetal and adult human liver and may account for polymorphism in metabolism of clinically important drugs.

Regulation of ventricular atrial natriuretic peptide release in hypertrophied rat myocardium. Effects of exercise

Left ventricular hypertrophy is characterized by stimulation of ventricular synthesis of atrial natriuretic peptide (ANP). This study was designed to test the hypothesis that the increased ventricular ANP levels participate in the release of ANP into the circulation. Swimming was used as a physiologic model to induce ANP release from the heart, and atrial and ventricular levels of immunoreactive ANP (IR-ANP) and ANP messenger RNA (mRNA) were measured simultaneously in the spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats at rest and after swimming. IR-ANP concentration in the left ventricle of 1-year-old SHR with severe left ventricular hypertrophy was increased in association with the augmentation of ANP mRNA levels, whereas right ventricular levels of ANP were reduced in SHR compared with normotensive controls. A 30-minute exercise in hypertensive and in normotensive rats resulted in marked increases in mean arterial pressure, heart rate, plasma catecholamine levels, blood lactate levels, and plasma IR-ANP concentration. The increased ANP secretion was associated with a decrease in left (34-39%) and right (24%) ventricular concentration of IR-ANP; transmurally, this depletion of ventricular IR-ANP was greatest (28%) in the endocardial layer of the left ventricle of SHR. No significant differences were noted in total atrial and left or right auricular IR-ANP concentration between SHR and WKY rats or between the resting and swimming rats. When studied in vitro with an isolated, perfused heart preparation, the hypertrophic ventricular tissue after atrialectomy secreted more ANP into the perfusate than did control hearts; in SHR, ventricles contributed 28% of the total ANP release to perfusate, and in normotensive control rats, ventricles contributed 8%. These studies show that stimulated release of ANP is associated with depletion of endocardial left ventricular stores. The amount of ANP released in vitro and in vivo correlated with the degree of hypertrophy of the ventricle. Finally, the phorbol ester, known to increase ANP secretion from intact perfused hearts, had only a limited effect on ANP release after atrialectomy, suggesting that the secretion of ANP from ventricular cells may be mainly of the constitutive type.

Detection of mRNA for the tax1/rex1 gene of human T-cell leukemia virus type I in fresh peripheral blood mononuclear cells of adult T-cell leukemia patients and viral carriers by using the polymerase chain reaction

Expression of human T-cell leukemia virus type I (HTLV-I) is not detectable by immunofluorescence analysis or RNA blot analysis in most fresh peripheral blood mononuclear cells of patients with adult T-cell leukemia or of asymptomatic HTLV-I carriers. However, in this work, mRNA for the HTLV-I tax1/rex1 genes was detected in fresh peripheral blood mononuclear cells of adult T-cell leukemia patients and asymptomatic HTLV-I carriers by using reverse transcription followed by the polymerase chain reaction. By using fresh peripheral blood mononuclear cells, the expression of tax1/rex1 mRNA was detected in five of the six adult T-cell leukemia patients and four of the eight HTLV-I carriers examined. The amounts of tax1/rex1 mRNA detected corresponded to approximately 10(5) to 10(6) times less than that in the HTLV-I-infected MT-2 cell line. These results indicate that, in some individuals infected with HTLV-I, the provirus in circulating blood cells is transcribed in vivo. Thus the expression of viral antigens in circulating blood cells in vivo is suggested.

A general approach to isolating Plasmodium falciparum genes using non-redundant oligonucleotides inferred from protein sequences of other organisms

We have constructed a number of oligonucleotide probes and tested their utility in identifying various genes in Plasmodium falciparum. The probe sequences were based on known conserved regions of proteins from other organisms, coupled with an analysis of the codon usage of the parasite. By using long single oligonucleotides, we have successfully isolated the DHFR-TS gene, two actin genes and two tubulin genes from the K1 (Thailand) isolate of P. falciparum. We compare these single probes to multiply-redundant short oligonucleotide probes and to heterologous probes. We also present a detailed quantitative analysis of optimal probe design, and of how this approach can best be implemented as a general method of isolating plasmodial genes.