Inhibition of heterologous DNA replication by the MVMp nonstructural NS-1 protein: identification of a target sequence

The nonstructural protein NS-1 of minute virus of mice (MVMp), an autonomous parvovirus, trans-inhibits the replication of a chimeric plasmid containing the SV40 origin of replication (ori) embedded in the MVMp genome. It appears that a 157-bp 5' proximal sequence of MVMp DNA is sufficient, in the presence of NS-1, to cause the inhibition of DNA replication driven by the SV40 ori placed on the same molecule. This effect is not dependent on the orientation of the MVMp target sequence and results from both a reduced level of utilization of SV40 ori and the blockage of progressing replication forks at the level of the target. Furthermore, replication driven by Epstein-Barr virus origin (oriP) is trans-inhibited by MVMp but this inhibition does not require the presence of parvoviral sequences in cis. On the basis of sequence homologies between EBV oriP and MVMp 5' terminal sequence, it is proposed that the direct or indirect interaction of NS-1 with parvovirus-like sequences present in heterologous viral and possibly also cellular genomes may result in an inhibition of DNA replication.

Human hnRNP protein A1 gene expression. Structural and functional characterization of the promoter

hnRNP protein A1 (34 kDa, pl 9.5) is a prominent member of the family of proteins (hnRNP proteins) that associate with the nascent transcripts of RNA polymerase II and that accompany the hnRNA through the maturation process and the export to the cytoplasm. New evidence suggests an active and specific role for some of these proteins, including protein A1, in splicing and transport. Contrary to the other hnRNP proteins, the intracellular level of protein A1 was reported to change as a function of proliferation state and cell type. In this work we analyse the A1 gene expression in different cells under different growth and differentiation conditions. Proliferation dependent expression was observed in lymphocytes and fibroblasts while purified neurons express high A1 mRNA levels both in the proliferative (before birth) and in the quiescent (after birth) state. Transformed cell lines exhibit very high (proliferation independent) A1 mRNA levels compared to differentiated tissues. A structural and functional characterization of the A1 gene promoter was carried out by means of DNase I footprinting and CAT assays. The observed promoter features can account for both elevated and regulated mRNA transcription. At least 12 control elements are contained in the 734 nucleotides upstream of the transcription start site. Assays with the deleted and/or mutated promoter indicate a co-operation of multiple transcriptional elements, distributed over the entire promoter, in determining the overall activity and the response to proliferative stimuli (serum).

Phosphorylation of human hnRNP protein A1 abrogates in vitro strand annealing activity

In HeLa cells metabolically labeled in vivo with [32P] orthophosphate in the presence of okadaic acid the concentration of phosphorylated A1 protein was increased significantly as compared to controls. Purified recombinant hnRNP protein A1 served as an excellent substrate in vitro for the catalytic subunit of cAMP-dependent protein kinase (PKA) and for casein kinase II (CKII). Thin layer electrophoresis of A1 acid hydrolysates showed the protein to be phosphorylated exclusively on serine residue by both kinases. V8 phosphopeptide maps revealed that the target site(s) of in vitro phosphorylation are located in the C-terminal region of A1. Phosphoamino acid sequence analysis and site directed mutagenesis identified Ser 199 as the sole phosphoamino acid in the protein phosphorylated by PKA. Phosphorylation introduced by PKA resulted in the suppression of the ability of protein A1 to promote strand annealing in vitro, without any detectable effect on its nucleic acid binding capacity. This finding indicates that phosphorylation of a single serine residue in the C-terminal domain may significantly alter the properties of protein A1.

A novel procedure for quantitative polymerase chain reaction by coamplification of competitive templates

A method is described for the absolute quantification by polymerase chain reaction (PCR) of nucleic acids present in low abundance. The method entails the addition to the sample of competitor DNA molecules that share the same sequence as the amplified target (including primer recognition sites), except for a 20-bp insertion in the middle, which allows easy resolution by gel electrophoresis (competitive PCR). Among the advantages of competitive PCR is that any predictable or unpredictable variable that affects amplification has the same effect on both target and competitor species and that the final ratio of amplified products reflects exactly the initial rate of targets, rendering the reaction independent of the number of amplification cycles. An easy and reliable method for the construction and quantification of competitive templates obtained as recombinant PCR products was developed. The technique was used for the absolute quantification of human genomic DNA with primers from a single copy, subtelomeric region of chromosome 19.

A human DNA replication origin: localization and transcriptional characterization

A single-copy 13.7 kb human DNA region (L30E) located on Ch. 19 p13.3 contains an origin of DNA replication in myeloid HL-60 cells. The origin was localized, by means of quantitative PCR within approximately 3000 bp, in a highly transcribed region containing at least two closely spaced genes with the same polarity of transcription, one encoding lamin B2 and the other an unidentified protein. The origin region overlaps an undermethylated "CpG island" at the 5'-end of the second transcription unit. A binding site (CACGTG) for basic helix-loop-helix (bHLH) DNA binding proteins such as USF/MLTF or MYC-MAX was located by DNase I footprinting analysis in the promoter of the second gene. DMSO differentiation of HL-60 cells, that completely shuts off replication, also drastically reduces the transcription of L30E region. On the other hand such treatment does not modify the methylation pattern of the CpG island and does not abolish the DNase I protection of the bHLH binding site.

[Usefulness of temporal bicameral stimulation in the interruption of refractory ventricular tachycardia]

The occurrence of sustained ventricular tachycardia with worsening hemodynamic performance in patients with ischemic heart disease can represent a critical event when the arrhythmia, refractory to antiarrhythmic drugs, recurs after D.C. shock. In this case temporary DDD pacing can be a reliable alternative treatment.

Interaction of hnRNP A1 with snRNPs and pre-mRNAs: evidence for a possible role of A1 RNA annealing activity in the first steps of spliceosome assembly

The in vitro interaction of recombinant hnRNP A1 with purified snRNPs and with pre-mRNAs was investigated. We show that protein A1 can stably bind U2 and U4 snRNP but not U1. Oligo-RNAse H cleavage of U2 nucleotides involved in base pairing with the branch site, totally eliminates the A1-U2 interaction. RNase T1 protection and immunoprecipitation experiments demonstrate that recombinant protein A1 specifically binds the 3'-end regions of both beta-globin and Ad-2 introns. However, while on the beta-globin intron only binding to the polypyrimidine tract was observed, on the Ad-2 intron a 32 nt fragment encompassing the branch point and the AG splice-site dinucleotide was bound and protected. Such protection was drastically reduced in the presence of U2 snRNP. Altogether these results indicate that protein A1 can establish a different pattern of association with different pre-mRNAs and support the hypothesis that this protein could play a role in the annealing of U2 to the branch site and hence in the early events of pre-splicing complex assembly.

The gene for a novel human lamin maps at a highly transcribed locus of chromosome 19 which replicates at the onset of S-phase

A previously described human DNA fragment which is replicated early in S-phase of HL-60 cell DNA (C. Tribioli, G. Biamonti, M. Giacca, M. Colonna, S. Riva, and A. Falaschi, Nucleic Acids Res. 15:10211-10232, 1987) was used to screen a genomic library in lambda Ch28. A clone which contained a 13.7-kb insert (L30E) found to code for several transcripts was isolated. The transcription of L30E DNA exhibited a complex pattern and a tissue-specific and proliferation-dependent type of regulation. The data were consistent with two tandemly arranged transcription units, the 3' end of one separated from the 5' end of the other by a sequence of about 600 bp containing an active promoter. The isolation and sequencing of L30E-specific cDNAs permitted identification of two genes, one of which encoded a B-type human lamin (analogous to mouse lamin B2). L30E DNA was mapped by in situ hybridization at the G-negative subtelomeric band p13.3 of chromosome 19. Interestingly, in synchronized HL-60 cells, L30E DNA is replicated in the first minute of S-phase. Replication of the lamin gene early in S-phase may reflect a coupling between early replication and transcription of genes for S-phase-specific proteins such as lamins.

H-NMR studies of native and fragmented subtilisin Carlsberg

NMR studies have been carried out on subtilisin Carlsberg in order to identify the sharp resonances observed in the proton spectra of the enzyme dissolved in aqueous solution. NMR spectra, obtained with the combination of spin-echo and selective excitation sequences, from both the native and inactivated protein, enabled us to assign sharp signals to subtilisin fragments derived from enzymatic autolysis (monitored by high-performance size-exclusion chromatography), rather than to mobile segments of the intact protein.

Assignment of the human heterogeneous nuclear ribonucleoprotein A1 gene (HNRPA1) to chromosome 12q13.1 by cDNA competitive in situ hybridization

Heterogeneous nuclear ribonucleoprotein (HNRP) core protein A1 is a major component of mammalian HNRP particles. The human HNRP A1 protein was shown to be encoded by a 4.6-kb gene, split into 10 exons, belonging to a multigene family of about 30 A1-specific sequences per haploid genome, many of which correspond to pseudogenes of the processed type. Here we report the mapping of the human HNRPA1 gene to band 12q13.1. Localization was performed by nonisotopic in situ hybridization using a phage genomic clone that contains the active HNRPA1 gene as well as 13.5-kb flanking sequences. To suppress hybridization to pseudogene sequences, unlabeled HNRPA1 cDNA was added in excess over the probe to the hybridization mixture.

Coenzymatic properties of low molecular-weight and macromolecular N6-derivatives of NAD+ and NADP+ with dehydrogenases of interest for organic synthesis

The catalytic activity, expressed as Km and Vmax values, of 16 enzymes of practical interest with the macromolecular coenzymes poly(ethylene glycol)-N6-(2-aminoethyl)-NAD+ and poly(ethylene glycol)-N6-(2-aminoethyl)-NADP+ and their low molecular weight precursors N6-(2-aminoethyl)-NAD+ and N6-(2-aminoethyl)-NADP+, was investigated. The enzymes examined are of direct interest for organic synthesis (i.e. alcohol dehydrogenase from yeast, horse liver, or Thermoanaerobium brockii, lactic dehydrogenase, and several hydroxysteroid dehydrogenases) or are used for the regeneration of NAD+, NADP+, NADH, or NADPH (i.e. glutamate dehydrogenase from liver or Proteus, formate dehydrogenase, glucose dehydrogenase, and malic enzyme). The cycling efficiency of poly(ethylene glycol)-N6-(2-aminoethyl)-NADP+ was examined with coupled-enzymes or coupled-substrates systems. Poly(ethylene glycol)-N6-(2-aminoethyl)-NAD+ and, even more so, poly(ethylene glycol)-N6-(2-aminoethyl)-NADP+ were excellent coenzymes with several dehydrogenases. In addition, the coenzymatic properties of N6-(3-sulfonatopropyl)-NAD+, an NAD+ derivative carrying a strong anionic group, were compared with those of the newly synthesized N6-(2-hydroxy-3-trimethylammonium propyl)-NAD+, an NAD+ derivative carrying a strong cationic group. It was expected that the presence of the sulfonic or quaternary ammonium group would enhance the residence time of the coenzyme inside continuous-flow reactors if membranes with anionic or cationic groups, respectively, were used.

Acute and chronic efficacy of felodipine in congestive heart failure

In 13 patients with congestive heart failure we tested the acute hemodynamic effects of 5 vs. 10 mg felodipine tablets, in a double-blind, cross-over study. One hour after felodipine 5 mg, echocardiographic ejection fraction (%), cardiac index (thermodilution-ml/min/m2), and pulmonary wedge pressure (mm Hg) significantly changed (from 21 +/- 2 to 26 +/- 2, 2350 +/- 150 to 2790 +/- 160, 24 +/- 4 to 17 +/- 4) while they remained steady after felodipine 10 mg. The greatest stroke index increases were associated with felodipine 5 mg in 12 patients and 10 mg in 1 patient. Therefore we evaluated (open study) the long-term (2 months- 1 year) clinical and hemodynamic efficacy following the treatment with the acutely most effective dose (twice daily). After 2 months ejection fraction, cardiac index and pulmonary wedge pressure were respectively 24 +/- 2, 2550 +/- 150, and 18 +/- 4 (12 hours after the last drug administration, n = 11, P less than 0.02 from baseline). These parameters further increased one to two hours after the following administration of felodipine. Clinical improvement (reduction of 1 functional class, according to the New York Heart Association) was observed in 8/13 patients. These 8 patients participated to the one year follow-up. In 5 patients follow-up was interrupted because of acute cardiovascular events. However, before study interruption (5 patients) or ending (3 patients) clinical status did not worsen and ejection fraction remained higher than in the pretreatment period. Therefore, low dose felodipine might be used in the treatment of congestive heart failure.

Recombinant hnRNP protein A1 and its N-terminal domain show preferential affinity for oligodeoxynucleotides homologous to intron/exon acceptor sites

The reported binding preference of human hnRNP protein A1 for the 3'-splice site of some introns (Swanson and Dreyfuss (1988) EMBO J. 7, 3519-3529; Mayrand and Pederson (1990) Nucleic Acids Res. 18, 3307-3318) was tested by assaying in vitro the binding of purified recombinant A1 protein (expressed in bacteria) to synthetic oligodeoxynucleotides (21-mers) of suitable sequence. In such a minimal system we find preferential binding of protein A1 to oligodeoxynucleotide sequences corresponding to the 3'-splice site of IVS1 of human beta-globin pre-mRNA and of IVS1 of Adenovirus type 2 major late transcript. Mutation studies demonstrate that the binding specificity is dependent on the known critical domains of this intron region, the AG splice site dinucleotide and polypyrimidine tract, and resides entirely in the short oligonucleotide sequence. Moreover specific binding does not require the presence of other hnRNP proteins or of snRNP particles. Studies with a truncated recombinant protein demonstrated that the minimal protein sequence determinants for A1 recognition of 3'-splice acceptor site reside entirely in the N-terminal 195 aa of the unmodified protein.

[The right ventricle and pulmonary circulation in hypertensive patients]

Elevated blood pressure and vascular resistance in patients with systemic hypertension are paralleled by a proportional rise in pressure and resistance in the lesser circulation. It was hypothesized that increased systemic reaction to adrenergic stimulation is shared by the pulmonary vessels. Thus normotensive subjects and patients with primary hypertension were investigated during mental arithmetic and the cold pressor test. Both groups responded to both stimuli; during arithmetic pressure reaction was mediated through an increase of cardiac output, and during the cold pressor test through a predominant rise in systemic vascular resistance. The pressure changes were emphasized in the hypertensive population. Pressure in the pulmonary artery in normotensive subjects was not affected by cold and was slightly raised (systolic) during arithmetic. In hypertensive patients, on the other hand, systolic and diastolic pressures were consistently augmented by both tests, and pulmonary arteriolar resistance rose by 42% and 29% of control during the cold pressor test and arithmetic, respectively. Changes in resistance reflected neurally-mediated vasoconstriction but not variations in the passive relationship between pressure and flow, since during arithmetic, for a similar rise in flow the driving pressure across the lungs was steady in normotensive subjects and rose significantly in hypertensive patients. In these same patients pressure was augmented by cold test in the absence of substantial changes in flow. At baseline and during tests pulmonary wedge pressure, pleural pressure, arterial blood gases, and pH were similar in the two populations. The intravenous infusion of similar scalar doses of norepinephrine (the same mediator released during cold test) was not effective on the pulmonary vessels of normotensives and caused an obvious vasoconstriction in hypertensives.(ABSTRACT TRUNCATED AT 250 WORDS)

Alternative splicing in the human gene for the core protein A1 generates another hnRNP protein

The human hnRNP core protein A1 (34 kd) is encoded by a 4.6 kb gene split into 10 exons. Here we show that the A1 gene can be differentially spliced by the addition of an extra exon. The new transcript encodes a minor protein of the hnRNP complex, here defined A1B protein, with a calculated mol. wt of 38 kd, that coincides with a protein previously designated as B2 by some authors. In vitro translation of the mRNAs selected by hybridization with A1 cDNA produced two proteins of 34 and 38 kd; Northern blot analysis of poly(A)+ RNA from HeLa cells revealed that the abundance of the A1B mRNA was approximately 5% that of A1. The A1B protein was detected by Western blotting with an anti-A1 monoclonal antibody both in enriched preparations of basic hnRNP proteins and in 40S hnRNP particles. The A1B protein exhibits a significantly higher affinity than A1 for ssDNA. The recombinant A1B protein, expressed in Escherichia coli, shows the same electrophoretic mobility and charge as the cellular one.

[ST segment depression in precordial leads in patients with inferior acute myocardial infarction: the role of right ventricular involvement]

The aim of the present study was to evaluate the influence of right ventricular involvement on the magnitude of precordial ST segment depression during inferior acute myocardial infarction. For this reason 61 patients (55 M, 6 F; mean age 53 years--range 38-73 years) admitted in our CCU for inferior acute myocardial infarction were studied by coronary angiography within 3-5 days from the onset of symptoms. The angiography showed either occlusion or critical coronary stenosis ranging as follows: on right coronary artery proximal (Group 1) to the first branch for right ventricle in 22 patients, on right coronary artery distal to the first branch for right ventricle in 25 patients (Group 2) and on circumflex artery (Group 3) in 14 patients. No difference in LAD disease were noted between the 3 groups. Using myocardial scintigraphy (Tc-99m- pyrophosphate) we confirmed the presence or the absence of right ventricular involvement in the 3 groups. In the 3 groups the magnitude of ST segment depression in V2, selected as representative left-sided precordial lead, ranged as follows: Group 1: -0.25 +/- 1.34 mm; Group 2: -1.64 +/- 1.80 mm; Group 3: -2.00 +/- 1.97 mm. In patients with right ventricular involvement (Group 1) there was a statistically significant reduction of precordial ST segment depression either in comparison to Group 2 (p less than 0.01) or to Group 3 (p less than 0.005) but none between Group 3 and 2. (ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic and renin responses to nifedipine in renovascular hypertension

We investigated the acute effects of nifedipine (10 mg orally) on renin and systemic hemodynamics in twelve patients who had severe hypertension (diastolic values averaging 114 mm Hg) with unilateral renal artery stenosis (angiography) and hyperreninemia. Plasma renin activity was determined from blood samples drawn from the aorta and from both renal veins, so that "ischemic lateralization" could be evaluated through appropriately derived indexes. Nifedipine promptly and significantly lowered aortic pressure in all patients. At 30 minutes maximal circulatory responses were recorded, which consisted of a 22% decrease in mean aortic pressure (from an average of 144.6 +/- 15 mm Hg to an average of 113 +/- 11 mm Hg), a 44% reduction of systemic vascular resistance (from 2162 +/- 540 dynes.sec.cm-5 to to 1205 +/- 279 dynes.sec.cm-5), a 33% rise in cardiac index (from 2920 +/- 970 ml/min/m2 to 3875 +/- 986 ml/min/m2). These effects were still evident, although somewhat tempered, after 180 minutes of continuous monitoring; they were qualitatively and quantitatively similar to those reported by some authors in persons with primary hypertension with similar levels of blood pressure. After nifedipine was given, renin activity of the systemic blood rose significantly, because of a potentiated release from the kidney with arterial stenosis. This effect, which was inferred as being due to further reduction of the renal perfusion pressure, improved the significance of "ischemic lateralization" indexes and supported the diagnosis of renovascular hypertension in all cases.(ABSTRACT TRUNCATED AT 250 WORDS)

A protein target site in an early replicated human DNA sequence: a highly conserved binding motif

We have previously reported that a human nuclear factor, probably corresponding to the USF/MLTF protein [1,2], is able to bind specifically to a DNA sequence present in DNA replicated at the onset of S-phase [3]. Here we demonstrate that the same factor binds also to several other similar sequences, present in eukaryotic and viral genomes. Mutations or methylation in a CpG dinucleotide, central in the palindromic binding site, completely abolish binding. Furthermore, we present evidence for the existence of at least two other nuclear proteins in human cells with the same DNA binding specificity. The data presented suggest a strong evolutionary conservation, among distantly related organisms, of the binding motif, which is probably the target of a number of nuclear factors that share the same DNA binding specificity albeit in the context of different functions.

Enzymatic synthesis of [4R-2H]NAD (P)H and [4S-2H]NAD(P)H and determination of the stereospecificity of 7 alpha- and 12 alpha hydroxysteroid dehydrogenase

The stereospecifically labeled coenzymes [4R-2H]NADH, [4R-2H]NADPH and [4S-2H]NAD(P)H were synthesized enzymatically in high yield and high isotopic purity (greater than or equal to 95%) with 2HCOO2H/formate dehydrogenase, (CH3)2C2HOH/alchol dehydrogenase from Thermoanaerobium brockii and [1-2H]glucose/glucose dehydrogenase, respectively. This set of deuterated coenzymes was used to determine the stereospecificity of the previously unstudied 7 alpha-hydroxysteroid dehydrogenase from Escherichia coli (NAD-dependent) and 12 alpha-hydroxysteroid dehydrogenase from Clostridium group P (NADP-dependent). H-NMR and EI-MS of the nicotinamide moiety after enzymatic oxidation of deuterated NAD(P)H with dehydrocholic acid as substrate showed that both dehydrogenases are B-sterospecific.

Isolation of an active gene encoding human hnRNP protein A1. Evidence for alternative splicing

Heterogeneous nuclear ribonucleoprotein (hnRNP) core protein A1 is a major component of mammalian hnRNP 40 S particles. We describe the structure of an active A1 gene and report on the partial characterization of the A1 gene family. About 30 A1-specific sequences are present per haploid human genome: 15 such sequences were isolated from a human genomic DNA library. Many corresponded to pseudogenes of the processed type but by applying a selection for actively transcribed regions we isolated an active A1 gene. The gene spans a region of 4.6 x 10(3) base-pairs and it is split into ten exons that encode the 320 amino acid residues of the protein. The amino acid sequence derived from the exon sequences is identical with that deduced from cDNA and reported for the protein. One intron exactly separates the two structural domains that constitute the protein. Each of the two RNA-binding domains in protein A1 is encoded by one exon. Experimental evidence indicates that the A1 gene can encode for more than one protein by alternative splicing. The gene is preceded by a strong promoter that contains at least two CCAAT boxes and two possible Sp1 binding sites, but it lacks a TATA box.

[Hemodynamic effects of the intravenous administration of captopril in patients with chronic congestive heart failure]

The aim of the present study was to evaluate the hemodynamic response to the intravenous administration of the angiotensin converting enzyme-inhibitor captopril. Plasmatic renin activity was also monitored. The study population included 10 patients with chronic congestive heart failure: 3 were in the second NYHA functional class, 5 in the third, and 2 in the fourth. The patients received a first dose of 5 mg of captopril followed, after 10 min, by a second bolus-dose of 15 mg. Hemodynamic and hormonal measurements were repeated in the following 4 hours. The greatest hemodynamic effect, considered as the time of maximal mean arterial pressure and systemic vascular resistances decrease, and cardiac index increase, was noted 20 min after the first bolus dose administration. Mean arterial pressure (MAP) decreased by 13% (p less than 0.01), mean pulmonary artery pressure (MPAP) by 14% (p less than 0.05), right atrial pressure (RAP) by 30% (NS), wedge pressure (WPP) by 23% (p less than 0.01), systemic vascular resistances (SVR) by 21% (p less than 0.05), pulmonary vascular resistances by 22% (NS); cardiac index (CI) increased by 12% (p less than 0.05), stroke volume index by 10% (NS). Heart rate didn't change. The plasmatic renin activity (PRA) increased by 339% (p less than 0.01) reaching the maximal level in concomitance with the greatest hemodynamic effect. Hemodynamic changes were already noted 5 min after the first dose and lasted up to 75 min later.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnosis of acute myocardial infarction by indium-111 antimyosin antibodies and correlation with the traditional techniques for the evaluation of extent and localization

This clinical study evaluated the accuracy of planar myocardial scintigraphy with antimyosin monoclonal antibodies radiolabeled with indium-111 (AMA-Fab) in the detection and localization of acute myocardial infarction (AMI). Fifty-seven patients admitted for suspected AMI were studied; 17 patients underwent thrombolytic therapy with intravenous streptokinase and 11 had clinical signs of reperfusion; 9 had had a previous myocardial infarction. Fifty of 57 patients were discharged from the coronary care unit with a confirmed diagnosis of AMI. The AMA-Fab study results were positive for AMI in 49 patients (98%) and negative in 1 (2%). Among the 7 patients without AMI, 5 had unstable angina, 1 had Prinzmetal's variant angina and 1 had acute pancreatitis. AMA-Fab results were negative in 6 of 7 patients (85%) and positive in 1 (15%). Therefore, the sensitivity and specificity of AMA-Fab scintigraphy were 0.98 and 0.85, respectively. To assess accuracy in defining the extent and location of AMI, AMA-Fab results were compared with those of the electrocardiogram, echocardiogram, technetium-99m pyrophosphate myocardial scintigraphy and coronary angiography and left ventriculography. AMA-Fab scintigraphy showed a good concordance with the traditional techniques in the topographic definition of the infarcted regions. No uptake of AMA-Fab was seen in the regions of previous old infarcts. Ten healthy volunteers also underwent AMA-Fab scintigraphy. No evidence of myocardial tracer uptake was noted in them. No adverse reactions or side effects were noted after injection of AMA-Fab in any patient. It is concluded that planar myocardial scintigraphy with AMA-Fab is a reliable method for AMI detection and location.

Presence of transcription signals in two putative DNA replication origins of human cells

We describe the purification and cloning of human DNA replicated at the onset of S phase in HL60 cells synchronized with aphidicolin. A survey of the overall structural properties of these sequences did not show any distinctive features except for an enrichment in Cot0 DNA. The two longer fragments were completely sequenced and studied in more detail. Both were shown to contain transcriptional signals associated with promoters and/or enhancers, such as the binding sites of Sp1, T antigen and nuclear factor III. In one instance, a binding site for a known cellular transcription factor (USF/MLTF) was located inside the sequence by footprinting. Accordingly, by CAT assay and Northern blot, the same sequence was shown to contain an active promoter. The significance of these findings with respect to the role of transcription in initiation of DNA replication at the origin is discussed. None of the tested fragments exhibited autonomously replicating sequence (ARS) activity in transfected cells. The problems connected with the detection of ARS activity in human cells are critically examined.

Circular dichroism and fluorescence of polyethylene glycol-subtilisin in organic solvents

Subtilisin Carlsberg has been made soluble in organic solvents such as dioxane and acetonitrile by covalent linking to polyethylene glycol. Far-ultraviolet circular dichroism and intrinsic protein fluorescence have shown that subtilisin dissolved in dioxane, in which the enzyme is active and highly stable, maintains the native secondary structure as well as the native microenvironment for tyrosyl residues. In acetonitrile subtilisin undergoes conformational changes that cause enzyme inactivation and precipitation.

Combined hemodynamic overload of the left and right ventricles as a possible cause of interventricular septum preponderance in high blood pressure

We tested whether overload of the two ventricles may be associated with a preponderance of interventricular septum in patients with high blood pressure. The rationale is that the septum is shared by the greater and lesser circulation and that in hypertension the latter shows the same qualitative hemodynamic alterations as the former. Among 65 hypertensive patients, 40 (group 1) showed (echo) posterior wall thickness within the mean +/- 1 SD of 62 normal subjects, and 25 (group 2) had a posterior wall thickness exceeding the mean + 1 SD of the normal population. Both groups were subdivided into subgroups A and B, which included patients whose ventricular septum was similar to (within the mean + 1 SD) and thicker than (exceeding the mean + 1 SD) the posterior wall thickness in the corresponding group, respectively. Resting differences in systemic and pulmonary pressure and vascular resistance among subgroups 1A, 1B, and 2A were not significant; however, in subgroup 2B these variables exceeded those in the other subgroups to a significant extent. During cold pressor testing (CPT) the levels reached and the changes in pressure and resistance from baseline values in both circuits were much greater in subgroups B than in subgroups A. The baseline plasma norepinephrine value showed a trend toward an increase from subgroup 1A to 1B and from subgroup 2A and 2B; during CPT norepinephrine invariably changed and in subgroups B it rose significantly more than in subgroups A. It was not determined whether this caused the hemodynamic overload in subgroups B.(ABSTRACT TRUNCATED AT 250 WORDS)

Lack of tolerance development during chronic ibopamine administration to patients with congestive heart failure

Beta-adrenergic agonists can progressively lose their efficacy during chronic therapy in patients with heart failure. Ibopamine is a new dopamine derivative, active on dopaminergic and beta-adrenergic receptors, whose hemodynamic activity has been acutely demonstrated. To assess whether any attenuation of its efficacy occurs, the variations of the cardiac output induced during chronic therapy were monitored by impedance cardiography in 15 patients with dilated cardiomyopathy who showed a significant increase of the cardiac output (20.7 +/- 10.0%) after acute ibopamine administration. The efficacy of ibopamine was also assessed after 6 and 12 months of therapy by echocardiography, exercise testing, and 24-hour dynamic electrocardiogram (EKG) monitoring. The cardiac output response to ibopamine did not show any significant attenuation (range 15% to 19%) in the evaluations at 1, 2, 3, 4, 8, and 12 months of therapy. No significant change, was noted, after 6 and 12 months, in the exercise capacity (505 vs. 602 and 604 seconds) and the fractional shortening (16.2 vs. 18.3 and 18.5) without any change of the diastolic diameter. Ventricular arrhythmias were significantly reduced after 6, but not 12, months of therapy. No significant change in the New York Association (NYHA) functional class was noted at 6 and 12 months of therapy (2.4 +/- 5 vs. 2.3 +/- 7 and 2.4 +/-0.6, respectively). Our results show that ibopamine can maintain its hemodynamic activity even during chronic therapy.

The reproducibility of average ambulatory, home, and clinic pressures

The reproducibility of ambulatory, home, and clinic blood pressures was compared in 13 untreated mildly hypertensive and 14 normotensive subjects. Each subject had two sets of daily ambulatory recordings, home self-measured readings (over 6 days), and clinic measurements taken 2 weeks apart. Comparisons over the 2 weeks within and among the methods of measurements were made using a repeated-measures analysis of variance. The results showed that there was no consistent average change in the ambulatory or home pressures and no change in clinic diastolic pressures, but the clinic systolic pressure of the hypertensive subjects dropped 6 mm Hg (p less than 0.05), while that of the normotensive subjects showed no significant change. Test-retest correlations of each of the three methods were similar in magnitude, indicating a similar level of reliability. Test-retest correlations of the ambulatory standard deviations, however, were low, indicating a low reliability of this measure of daily pressure variability. These results suggest that the reproducibility of ambulatory pressures may be as good or better than that of home or clinic measurements. They also suggest that the average ambulatory pressure may be preferable as the measurement in clinical trials, since it may be less influenced by measurement anxiety, particularly in hypertensive subjects.

cDNA cloning of human hnRNP protein A1 reveals the existence of multiple mRNA isoforms

Protein A1 is one of the major component of mammalian ribonucleoprotein particles (hnRNP). Human protein A1 cDNA cloning and sequencing revealed the existence of at least two protein isoforms. Among the cDNAs examined, sequence differences were found both in the structural portion, leading to aminoacid changes (Tyr to Phe or Arg to Lys) and in the non translated 3'-region where two T-stretches of different length were observed. Interestingly one of the aminoacid substitutions falls into a consensus sequence common to many RNA binding proteins. Northern blot analysis of poly A+ RNAs from five human tissues revealed two mRNA forms of 1500 and 1900 n due to alternative polyadenylation. Analysis of genomic DNA showed at least 30 A1-specific sequences, some of which correspond to processed pseudogenes. These results suggest that protein A1 is encoded by a multigene family.

[Coronary angiographic study of patients with non-Q myocardial infarct: correlations with the initial electrocardiographic aspect and prognosis]

The purpose of our study was to evaluate, during the early phase, the coronary anatomy of the patients who suffered from an acute non-Q myocardial infarction (non-Q MI) and to correlate it with the ECG findings and with clinical evolution. We studied 76 patients (pts.), mean age 56 +/- 9 years, who had their a first non-Q MI (reinfarctions non included). They all underwent angiographic examination within an average period of 18 days (range 5-30 days). In the whole group of patients it is worthwhile noting: A) the elevated occurrence of left main lesions (11% of pts.) and multivessel disease (60%); B) the great percentage (41%) of patients with open infarct-related vessel but with very critical residual stenosis (above 90% of total lumen); C) the presence of collateral vessels in almost all the pts. (91%) with totally occluded infarct-related artery. During the 12 month follow-up, in all groups was a high occurrence (above 70%) of coronary events (postinfarction angina, reinfarction, aortocoronary by pass or PTCA). Furthermore, it is possible to identify a subgroup of patients presenting ST-segment depression with very unfavourable coronary anatomy (80% had multivessel disease, 30% of which had a left main critical stenosis) and high prognostic risk (90% occurrence of coronary events). In the subgroup with ST-segment elevation there was an elevated percentage (65%) of open infarct-related vessel, but with an important residual stenosis. Considering the advantages of revascularization interventions in these high risk patients with extensive residual jeopardized myocardium, we conclude that it is important that all patients with non-Q MI undergo early coronary angiography.

Characterization of human DNA sequences synthesized at the onset of S-phase

We developed a method of enrichment for DNA replicated at the onset of S-phase in synchronized human HL60 cells. About 200 such sequences were cloned. The analysis of this selected DNA sample showed that: 1) the cloned DNA fragments derive from a limited number (750-1500) of replicons; 2) there is no extensive homology between different DNA fragments; 3) they are not significantly enriched in highly repeated sequences; 4) they are enriched in snap-back (Cot = o) DNA. The sequence of the longest fragment revealed the presence of numerous signals collected in a few hundred nucleotides: 1) homology with the origin of replication of human Papovaviruses usually associated with potential stem-loop structures; 2) binding sites for known transcription factors and for another nuclear factor; 3) potential binding sites for the chromosome "scaffold".

Hybridization of oligodeoxynucleotide probes to RNA molecules: specificity and stability of duplexes

Images

Improvements of Western blotting to detect monoclonal antibodies

A comparison of the effects of different factors on the sensitivity of Western blotting technique to detect monoclonal antibodies is described. The major improvements were obtained by: A) renaturating the antigen in the gel before transferring it in carbonate buffer at pH 10 onto nitrocellulose and B) using alkaline-phosphatase-conjugated second antibody instead of peroxidase-conjugated second antibody.

Autoantibodies to purified nuclear proteins related to DNA metabolism during ageing and in SLE patients

In this study the specificity of circulating autoantibodies in ANA+ aged donors, ANA- donors and SLE patients was investigated by immunoblotting on total nuclear proteins and by ELISA on purified nuclear proteins, possibly related to DNA metabolism, such as DNA polymerase alpha, DNA-dependent ATPase, DNA Topoisomerase I, ssDBP, hnRNP, HMG and histones. Immunoblotting showed that sera from ANA+ aged donors present fewer antibodies to nuclear proteins, especially to those between 21,000 and 45,000, molecular weight (MW), than sera from SLE patients. When the specificity of antisera was further studied on purified nuclear proteins, it was found that the majority of sera from SLE patients react with most of the proteins tested, whereas sera from ANA+ aged donors mainly react with DNA polymerase alpha, DNA-dependent ATPase, DNA Topoisomerase I and histones. In addition, sera from a few ANA- donors also reacted with certain purified nuclear proteins in a statistically significant age-related manner.

[Incidence and clinical significance of involvement of the right ventricle in acute inferior myocardial infarction]

The purpose of our study was to evaluate, with noninvasive procedures, the incidence and the clinical picture of right ventricular involvement in patients with acute transmural inferior myocardial infarction. Our study group was constituted of 107 consecutive patients admitted to our Coronary Care Unit within 10 hours from the onset of symptoms; in every patient a standard 12-leads ECG and the precordial leads V3R and V4R were obtained at admission in CCU and then every 12 hours. 80 patients underwent B-mode echocardiographic evaluation within 36 hours and in 93 patients a myocardial scintigraphy was performed, between the 48th and 72nd hour from the onset of chest pain, 1-2 hours after injection of Tc-99m-pyrophosphate.

RESULTS

45 patients (42.1%) had ECG positive for right ventricular infarction, 49 patients (51.6%) had positive Tc-99m-pyrophosphate scintigraphy and 24 patients (30%) positive echocardiography. By using the positivity of ECG and another method at least, patients were separated into 2 groups: group A (associated inferior and right infarction) was constituted of 45 patients, and group B (isolated inferior infarction) was constituted of 62 patients. In group A we noted a higher incidence of hypotension (systolic blood pressure less than 100 mmHg) and oliguria (less than 30 ml/h)- p less than 0.01-, of 2nd and 3rd A-V blocks-p less than 0.001- and primary ventricular fibrillation -p less than 0.01. The incidence of parossistic atrial fibrillation, severe bradycardia or SA blocks and of mortality was not statistically different between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Large-scale purification of hnRNP proteins from HeLa cells by affinity chromatography on ssDNA-cellulose

A purification procedure for proteins which bind heterogeneous nuclear RNA (hnRNP proteins) is described. The procedure, which entails standard chromatographic fractionations (single-stranded DNA cellulose, hydroxyapatite) and detection with specific antibodies, allows a large-scale preparation of these proteins and the partial separation of different polypeptides. By this method, polypeptides of higher molecular mass (53-55 kDa) can be purified, which are structurally and antigenically related to the 'canonical' hnRNP core proteins (34-43 kDa) that constitute the 40S hnRNP complexes. We also show that HeLa cells contain a protease that cleaves hnRNP core proteins to discrete smaller polypeptides of 22-28 kDa. Such protease, which has been partially purified, appears to copurify extensively with some of the hnRNP proteins.

Mammalian single-stranded DNA binding protein UP I is derived from the hnRNP core protein A1

Antibodies induced against mammalian single-stranded DNA binding protein (ssDBP) UP I were shown to be cross-reactive with most of the basic hnRNP core proteins, the main constituents of 40S hnRNP particles. This suggested a structural relationship between both groups of proteins. Using the anti-ssDBP antibodies, a cDNA clone (pRP10) was isolated from a human liver cDNA library in plasmid expression vector pEX1. By DNA sequencing this clone was shown to encode in its 949 bp insert the last 72 carboxy terminal amino acids of the ssDBP UP I. Thereafter, an open reading frame continued for another 124 amino acids followed by a UAA (ochre) stop codon. Direct amino acid sequencing of a V8 protease peptide from hnRNP core protein A1 showed that this peptide contained at its amino terminus the last 11 amino acids of UP I followed by 19 amino acids which are encoded by the open reading frame of cDNA clone pRP10 immediately following the UP I sequence. This proves that ssDBP UP I arises by proteolysis from hnRNP core protein A1. This finding must lead to a re-evaluation of the possible physiological role of UP I and related ssDBPs. The formerly assumed function in DNA replication, although not completely ruled out, should be reconsidered in the light of a possible alternative or complementary function in hnRNA processing where UP I could either be a simple degradation product of core protein A1 (as a consequence of controlling the levels of active A1) or may continue to function as an RNA binding protein which has lost the ability to interact with the other core proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Single stranded DNA binding proteins derive from hnRNP proteins by proteolysis in mammalian cells

As we have previously demonstrated, mammalian single stranded DNA binding proteins (ssDBP) and heterogeneous nuclear RNA binding proteins (hnRNP proteins) are antigenically and structurally related. In this paper we show that ssDBP are specific proteolytic products of hnRNP core proteins. Proteolysis can be observed in crude extract, both total and nuclear and is not inhibited by the most commonly used protease inhibitors. Such phenomenon can be observed in HeLa cells, human fibroblasts and calf thymus extracts. A trypsin-like protease that cleaves purified hnRNP proteins to give ssDBP of Mr = 24-28 Kd can be purified from HeLa cells. A precursor-product relationship can be established between hnRNP core proteins type A and an ssDBP of 24 Kd (UP1).

Fate of exogenous recombinant plasmids introduced into mouse and human cells

We have constructed a number of plasmids selectable in both E. coli and mouse or human cells. Human DNA sequences were inserted and the recombinant plasmids were used to transfect either mouse or human cells by the Ca-phosphate precipitation technique. We have observed that: (i) competent cells uptake large amounts of plasmid DNA; (ii) input plasmids persist in transformed mammalian cells as free unreplicating circular molecules for up to 20 generations; such persistence does not depend on the presence of selective markers; (iii) plasmids incorporated into mouse L-cells undergo widespread rearrangements (in the absence of replication) entailing mostly deletions of both human and bacterial sequences which yield smaller products; the latter appear to be more stable in a subsequent transformation cycle. Surprisingly such rearrangements are almost totally absent in transformed human KB-cells. This property of human KB-cells may prove useful for the development of a vector apt at cloning and expressing human DNA sequences. Unlike what has been observed in yeast, no "autonomously replicating sequence" can be detected in mammalian cells by randomly cloning human DNA sequences into a selectable plasmid and screening for an increased transformation efficiency.

Hemodynamic advantage of combined administration of oral ibopamine and nitroprusside in patients with ischemic and idiopathic congestive cardiomyopathy

The hemodynamic effects of combined administration of ibopamine (Ib) (150 mg orally) with nitroprusside (NP) (50-150 micrograms/min intravenously) were compared with those of NP alone in 17 patients with severe congestive heart failure due to coronary artery disease (7 patients) or idiopathic cardiomyopathy (10 patients). Hemodynamic measurements were obtained using a Swan-Ganz thermodilution catheter and a bedside thermodilution cardiac output computer. Nitroprusside alone produced a significant decrease (-12.4%) in mean arterial pressure, mean pulmonary arterial pressure (-28.3%), and systemic vascular resistance (-22.6%), and a significant increase in stroke volume index (23.1%). The administration of combined NP and Ib produced a further significant increase of stroke volume index (20.1%) with a concomitant and significant reduction of systemic vascular resistance (-19.4%); heart rate, mean systemic and pulmonary arterial pressures did not change significantly from the values observed with NP alone. Moreover, stroke work index, although not significantly modified with the vasodilator alone, was significantly increased over control values with NP + Ib association. Although NP alone induced similar effects in both the ischemic and idiopathic cardiomyopathies, the association of Ib gave a more favorable, though not significant, hemodynamic response in the subjects with primitive cardiomyopathy than in the ischemic ones. Thus, the association of Ib to NP therapy, in patients with congestive heart failure, further increases stroke volume index and stroke work index with a concomitant reduction of systemic vascular resistance, without any significant change in mean systemic and pulmonary arterial pressures, or heart rate. These results point out the possibility of associating Ib with other orally active vasodilators in the chronic treatment of congestive heart failure.