Deep Learning Models for Predicting Left Heart Abnormalities From Single-Lead Electrocardiogram for the Development of Wearable Devices

BACKGROUND

Left heart abnormalities are risk factors for heart failure. However, echocardiography is not always available. Electrocardiograms (ECGs), which are now available from wearable devices, have the potential to detect these abnormalities. Nevertheless, whether a model can detect left heart abnormalities from single Lead I ECG data remains unclear.Methods and Results: We developed Lead I ECG models to detect low ejection fraction (EF), wall motion abnormality, left ventricular hypertrophy (LVH), left ventricular dilatation, and left atrial dilatation. We used a dataset comprising 229,439 paired sets of ECG and echocardiography data from 8 facilities, and validated the model using external verification with data from 2 facilities. The area under the receiver operating characteristic curves of our model was 0.913 for low EF, 0.832 for wall motion abnormality, 0.797 for LVH, 0.838 for left ventricular dilatation, and 0.802 for left atrial dilatation. In interpretation tests with 12 cardiologists, the accuracy of the model was 78.3% for low EF and 68.3% for LVH. Compared with cardiologists who read the 12-lead ECGs, the model's performance was superior for LVH and similar for low EF.

CONCLUSIONS

From a multicenter study dataset, we developed models to predict left heart abnormalities using Lead I on the ECG. The Lead I ECG models show superior or equivalent performance to cardiologists using 12-lead ECGs.

Clinical feasibility of endovascular recanalization with intravascular ultrasound-guided wiring for chronic total occlusion of below-the-knee arteries

BACKGROUND

Revascularization with endovascular therapy (EVT) for complex below-the-knee (BTK) chronic total occlusion (CTO) remains a challenging problem. The Japanese-BTK (J-BTK) CTO score is reported as an indicator of the difficulty of BTK CTO, with the guidewire (GW) passage success rate decreasing as the grade increases. We previously reported an effective GW crossing method for the intravascular ultrasound (IVUS)-guided parallel wiring of complex BTK CTO. In this study, we investigated the feasibility of EVT using IVUS-guided wiring for BTK CTO.

MATERIALS AND METHODS

This single center, retrospective study analyzed 65 consecutive BTK CTO vessels in which IVUS-guided wiring was attempted after the failure of a conventional antegrade wiring approach from November 2020 to November 2022. The primary endpoint was the clinical success of the target CTO vessel. The secondary endpoints were the GW success rate per grade based on the J-BTK CTO score, number of GW used for CTO crossing, fluoroscopy time, and complications.

RESULTS

Target vessels were the anterior tibial artery (66.2% of cases), peroneal artery (9.2%), and posterior tibial artery (24.6%). Blunt type CTO entry was performed in 55.4% of cases, calcification of entry was observed in 24.6% of cases, the mean occlusion length was 228.2 ± 93.7 mm, mean reference vessel diameter was 2.1 ± 0.71 mm, and outflow was absent in 38.5% of cases. J-BTK CTO scores of 0/1 (grade A), 2/3 (grade B), 4/5 (grade C), and 6 (grade D) were seen in 18.5%, 43.1%, 36.3%, and 1.5% of cases, respectively. The clinical success rate was 95.4%. The GW success rate by J-BTK CTO grade was as follows: grade A (100%), B (100%), C (91.7%), and D (0%). The mean number of GW used was 3.4 ± 1.4, the mean fluoroscopy time was 72.3 ± 32.5 min, and complications occurred in 7.7% of cases.

CONCLUSION

This study showed a very high clinical success rate despite the difficulty of BTK CTO. IVUS-guided EVT might be a feasible strategy for complex BTK CTO.

A tumour vaccine of fixed tumour fragments in a controlled-release vehicle with cytokines for therapy of hepatoma in mice

BACKGROUND

Cytokines can be strong potentiators for a tumour vaccine, but they have very short life in vivo when administered as a solution.

AIMS

To evaluate the slow release of interleukin 2 from a cytokine-vehicle in vitro and in vivo and to evaluate the anti-tumour activity of a new tumour vaccine in vivo.

METHODS

The tumour vaccine was composed of formalin-fixed Hepa 1-6 hepatoma tissue fragments, tuberculin and a lipid based vehicle containing granulocyte-macrophage colony-stimulating factor and interleukin 2. The quantity of interleukin 2 release from the cytokine-vehicle in vitro and in vivo was determined by a proliferation assay with CTLL-2 cell line. Hepa 1-6 hepatoma model system with C57BL/6J mice was used to examine protective and therapeutic anti-tumour effect of the vaccine.

RESULTS

Release of interleukin 2 from the cytokine-vehicle lasted 5 days in vitro and 3 days in vivo. The vaccine protected 67% of mice from a Hepa 1-6 cell challenge and had a therapeutic effect by prolonging the life span of mice bearing established Hepa 1-6 tumours of 5 mm in diameter. Of the treated mice, 20% became completely tumour-free.

CONCLUSIONS

Formalin-fixed tumour fragments and cytokines in controlled-release vehicle are useful in the rational design of tumour vaccines.

Inhibitory effect of the class III antiarrhythmic drug nifekalant on HERG channels: mode of action

Nifekalant is a class III antiarrhythmic drug that has been shown to be effective against ventricular tachyarrhythmias in experimental animals and humans. We examined the detailed electrophysiological effects of nifekalant on human-ether-a-go-go-related gene (HERG) channels expressed in Xenopus oocytes. Nifekalant inhibited the HERG current in a concentration-dependent manner with an IC(50) value of 7.9 microM although the drug did not inhibit the minK current in Xenopus oocytes, suggesting selective inhibition of the rapid component of the delayed rectifier K(+) current (I(Kr)) in cardiomyocytes. Nifekalant showed a higher binding affinity for the open state than for the inactive state of HERG channels. Nifekalant inhibited HERG channels in a frequency-dependent manner. The onset of the blockade was rapid but the recovery from the block was slow. Nifekalant modified the voltage dependence and kinetics of HERG channel gating. Thus, nifekalant inhibits HERG channels in a voltage-dependent and frequency-dependent manner, and the inhibitory effect may underlie the clinical efficacy of the drug against ventricular tachyarrhythmias.

Influence of diabetes mellitus on left ventricular function in patients undergoing coronary artery bypass grafting

OBJECTIVES

Left ventricular function was assessed by two-dimensional echocardiography before and one year after coronary artery bypass grafting(CABG) in a series of patients with severe coronary artery disease with diabetes mellitus(DM) and without DM(non-DM).

METHODS

Twenty-three patients with DM and 50 patients without DM, all with no previous myocardial infarction, underwent two-dimensional echocardiography before CABG and one year after CABG, in a non-matched study. For a matched study, 31 patients without DM who had almost the same left ventricular function as DM patients at the baseline were selected to and compare the rate of improvement in left ventricular function between the DM group and the "matched" non-DM group.

RESULTS

In the non-matched study, patient characteristics were not significantly different between the 2 groups except for the incidence of congestive heart failure within one year before CABG, which was significantly higher in the DM group. Fractional shortening was significantly lower in the DM group at the baseline(p < 0.05) and also one year after CABG(p < 0.0001). Significant improvement in fractional shortening was seen in the non-DM group(p < 0.001), but not in the DM group. The left ventricular end-diastolic diameter(LVDd) was significantly larger in the DM group at the baseline(p < 0.01), and was still significantly larger in the DM group at one year after CABG(p < 0.01). No improvement in LVDd was seen in the DM group. In the matched study, fractional shortening of the non-DM group also showed significant improvement after CABG(p < 0.001). Moreover, the rate of improvement in fractional shortening was higher in the non-DM group than in the DM group(p < 0.05). LVDd tended to be larger in the DM group(p = NS).

CONCLUSIONS

Left ventricular dysfunction and left ventricular impaired improvement were seen in the patients with DM, and CABG improved left ventricular function in the patients without DM with poor left ventricular function. These findings indicate that CABG therapy may be inadequate for improving left ventricular function in patients with DM and severe left ventricular dysfunction at the baseline.

Brugada syndrome characterized by the appearance of J waves

We describe a patient with Brugada syndrome. The ST-segment elevation in precordial leads was revealed during admission, but the appearance of J waves was characteristic before ventricular fibrillation (VF), rather than ST-segment elevation. J waves have been reported to be associated with the presence of an Ito-mediated prominent action potential notch in the epicardium. It is considered that one of the mechanisms of this VF is due to heterogeneous distribution of the refractory period according to changes in K+ channels including Ito.

Angiotensin-converting enzyme inhibitor therapy affects myocardial fatty acid metabolism after acute myocardial infarction

BACKGROUND

Angiotensin-converting enzyme (ACE) inhibitor therapy has an early mortality benefit in unselected patients with acute myocardial infarction (AMI). However, the effects of ACE inhibition on myocardial fatty acid metabolism in this patient population have not been studied. We tested the hypothesis that ACE inhibitor therapy improves myocardial fatty acid metabolism and decreases mortality rate in patients after AMI.

METHODS

Forty-two patients after first anterior AMI and primary angioplasty were randomly assigned to titrated oral enalapril (n = 24) or placebo therapy (n = 18). Iodine 123-labeled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) single photon emission computed tomography imaging was performed an average of 4.8 days after AMI and 1 month after AMI. BMIPP abnormalities were quantified as a severity index by a polar map.

RESULTS

There were no significant changes in baseline characteristics, cardiac function, and angiographic findings between patients in the enalapril group and patients in the placebo group. However, BMIPP severity index from acute phase to chronic phase was significantly decreased in the enalapril-treated group (118+/-48 to 82+/-36, P<.05), but not in the placebo group (123+/-65 to 115+/-58, P not significant).

CONCLUSION

ACE inhibition therapy improved myocardial fatty acid metabolism and regional left ventricular function in patients after anterior AMI. BMIPP single photon emission computed tomography findings imply that this better outcome may be attributable to an improvement of cellular function with ACE inhibitors.

Age-dependent paraparesis in WKA rats: evaluation of MHC k-haplotype and HTLV-1 infection

Human T-cell leukemia virus type 1 (HTLV-1) infection is shown to be closely associated with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Although the occurrence of HAM/TSP was reported to be associated with MHC class II, the mechanism is still unclear. The WKA(RT1k) strain of rats was reported to develop HAM/TSP-like paraparesis after HTLV-1 infection, and was suggested to be an animal model of HAM/TSP. We asked whether MHC k-haplotype is specifically involved in the pathogenesis of paraparesis of WKA(RT1k) rats. We injected the HTLV-1 producing human T cells (MT-2 cells) intravenously into WKA(RT1k) rats and MHC congenic WKA.1L(RT1l) rats which have MHC l-haplotype of LEW rats on the WKA background. Positive antibody response to HTLV-1 antigens and presence of provirus in peripheral blood mononuclear cells confirmed that MT-2 cell-injected rats were infected with HTLV-1. Two of 13 MT-2 cell-injected WKA(RT1k) rats and five of 13 MT-2 cell-injected WKA.1L(RT1l) rats developed HAM/TSP-like hindlimb paraparesis between 16 and 26 months old. Interestingly, three of 14 MT-2 cell-uninjected WKA(RT1k) rats and four of 13 MT-2 cell-uninjected WKA.1L(RT1l) rats showed similar paraparesis between 15 and 26 months old. MHC k-haplotype is not specific to the development of paraparesis in WKA(RT1k) rats. The role of aging, genetic background, HTLV-1 infection and other factors on the development of HAM/TSP-like paraparesis in rats are discussed.

Long-term prognosis in achieving a 'stent'like' result from balloon angioplasty: 8 years' clinical outcome

This study evaluated the long-term prognosis of optimal 'stent-like' results, suboptimal results and failure of balloon angioplasty. The clinical data of 108 patients were examined during 8 years following balloon angioplasty. Based on the angiographic results, the patients were divided into 3 groups: Group A (n=59), <25% residual stenosis (ie, optimal stent-like result); Group B (n=43), 26-50% residual stenosis or large dissection (ie, suboptimal result); and Group C (n=6), >50% residual stenosis or stenosis could not be crossed (ie, failed angioplasty). Restenosis occurred in 20 of 43 patients (46.5%) in Group B, but only in 18 of 59 patients (30.4%) in Group A. Achieving stent-like results following balloon angioplasty significantly reduced the incidence of restenosis. Kaplan-Meier curves at 8 years demonstrated a survival rate without serious cardiac events of 83% in patients with stent-like results compared with 58% in those with suboptimal results and 17% in those with failed balloon angioplasty. In conclusion, the major finding of this study is that achieving stent-like results following balloon angioplasty reduces the incidence of restenosis, and 8-year survival without serious cardiac events after balloon angioplasty is significantly better in patients who have a stent-like result.

Transmission of human T-cell leukemia virus type 1 to mice

Human T-cell leukemia virus type 1 (HTLV-1) is associated with adult T-cell leukemia/lymphoma, HTLV-1-associated myelopathy/tropical spastic paraparesis, and other diseases. For prevention of the transmission of HTLV-1 and manifestation of these diseases, a small-animal model, especially a mouse model, would be useful. We injected HTLV-1-producing T cells (MT-2) intraperitoneally into neonatal C3H/HeJ mice. While the antibody against HTLV-1 antigens was not detectable in C3H/HeJ mice, HTLV-1 provirus was frequently detected in the spleen, lymph nodes, and thymus by PCR. HTLV-1 provirus was present at the level of 0 to 30 molecules in 10(5) spleen cells at the age of 15 weeks. In addition, a 59-bp flanking sequence of the HTLV-1 integration site was amplified from the spleen DNA by linker-mediated PCR and was confirmed to be derived from the mouse genome. HTLV-1 provirus was found in the T-cell fraction of the mouse spleen. These results indicate that mice can be infected by HTLV-1 and could serve as an animal model for the study of HTLV-1 infection and its pathogenesis in vivo.

Inhibition of human T-cell leukemia virus type 1 replication by antisense env oligodeoxynucleotide

Human T-cell leukemia virus type 1 (HTLV-1) infection is associated with adult T-cell leukemia and HTLV-associated myelopathy/tropical spastic paraparesis. Inhibition of HTLV-1 transmission is important to prevent the above HTLV-1-associated diseases. We used the antisense oligodeoxynucleotides (oligos) complementary to the first splice junction, rex responsive site, gag, env, tax, rex, and p21 and evaluated the effects on the syncytium formation between HTLV-1 producing human T-cell line, C9/PL cells, and HTLV-1-uninfected human glioma cell line, U251-MG cells. The syncytium formation was significantly inhibited the virion production assayed by antisense oligos to env, tax, gag, p21, and rex, with antisense oligo to env being the most inhibitory. Antisense oligos to env and tax also inhibited reverse transcriptase activity. Antisense oligo to env may have a potential as a preventive measure of HTLV-1 replication and transmission in vivo.

Integration of HTLV-1 provirus into mouse transforming growth factor-alpha gene

Human T cell leukemia virus type 1 (HTLV-1) provirus integration was investigated in mice inoculated with MT-2 cells, a HTLV-1 producing human T-cell line. From spleen DNA derived from a MT-2 cell-injected mouse, we cloned a HTLV-1 integration site by ligation-mediated PCR. The nucleotide sequence showed that HTLV-1 provirus was integrated into an intron of the mouse transforming growth factor-alpha gene in the reverse orientation. This result provides for the first time molecular evidence that mice can be infected with HTLV-1.

Establishment of HTLV-1 carrier mice by injection with HTLV-1-producing T cells

We injected with HTLV-1-producing T-cells, MT-2, into C3H/HeJ and Balb/c mice intraperitoneally within 24 hours after birth and at one week old. At 3 months old, HTLV-1 provirus was detected in peripheral blood mononuclear cells in both mice. It was also detected in lymph nodes, thymus, spleen and liver of those mice. The antibody response against HTLV-1 Gag antigen was detected in some of Balb/c mice. These findings suggest that the C3H/HeJ and Balb/c mice were infected with HTLV-1 persistently. The HTLV-1-infected mice should be helpful for studying the pathological state of HTLV-1 carriers and for an establishment of a small animal model of HTLV-1 related diseases including ATL.

Pathogenesis and prevention of HTLV-1-associated diseases

HTLV-1 is an important factor involved in various diseases including adult T-cell leukemia/lymphoma and HTLV-1 associated myelopathy/tropical spastic paraparesis. Amount of HTLV-1 provirus integrated in human peripheral blood mononuclear cells might be a candidate for a risk factor in the manifestation of HTLV-1 associated diseases. Experimental animal models would be useful to dissect the pathogenesis of HTLV-1 associated diseases. We present rat and mouse models of HTLV-1 infection. Using these animal models, we could clarify the intrauterine transmission of HTLV-1, and have found that both genetic background and HTLV-1 infection are important in pathogenesis of HAM/TSP-like rats. We also discuss the preventive measures of HTLV-1 transmission by use of antisense oligonucleotides.

Inhibition of syncytium formation by antisense oligonucleotide phosphorothioates complementary to tax mRNA of human T-cell leukemia virus type 1 (HTLV-1)

HTLV-1 infection is known as the factor to cause adult T-cell leukemia (ATL). Antisense oligonucleotide phosphorothioates against tax gene and control oligonucleotide phosphorothioates were synthesized. Antisense oligonucleotide was complementary to the region of initiation codon of tax gene. Two control oligonucleotides were tax sense and random. HTLV-1-positive human T-cell line, C91/PL and HTLV-1 non-infected human glioma cell line, U251-MG were co-cultured in the presence of antisense or control oligonucleotides for 24 hours. Oligonucleotides used in this study were not toxic at 10 microM concentration. Antisense oligonucleotide against tax gene inhibited 59% the syncytium formation assay at 10 microM concentration.

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.

A neuropathological study of paraparetic rats injected with HTLV-I-producing T cells

In order to clarify the pathogenesis of HTLV-I-associated myelopathy or tropical spastic paraparesis (HAM/TSP), we injected HTLV-I-producing rabbit or human T cells intravenously into WKA and F344 rats. Infection was confirmed from increase in the anti-HTLV-I antibody titer and from the presence of HTLV-I proviral DNA. Only WKA rats developed hindlimb paraparesis 78-124 weeks after the injection. Neuropathological examination of 5 rats showed degeneration of the anterolateral and posterior funiculi as well as the peripheral nerves, and this degeneration was characterized by prominent vacuolation and macrophage infiltration. The myelopathy and neuropathy were grossly similar to those in human HAM/TSP. Although pathological changes of the spinal cord were very mild in 2 paretic rats, and similar lesions were found in the spinal cords and peripheral nerves of 2 control WKA rats, the myelopathy, radiculoneuropathy, or both in the paretic rats showed greater severity than in the controls. The contribution of the aging process to the lesions of the spinal cord and peripheral nerve is discussed. It appears possible that HTLV-I may accelerate the aging process and give rise to paraparesis. The precise role of HTLV-I in the pathogenesis of rat paraparesis remains to be elucidated taking the role of the aging process of the spinal cord and peripheral nerve into account.

Isolation of the poly(ADP-ribose) polymerase-encoding cDNA from Xenopus laevis: phylogenetic conservation of the functional domains

The complete nucleotide (nt) sequence of the Xenopus laevis poly(ADP-ribose) polymerase (PARP)-encoding cDNA was determined. The putative X. laevis PARP protein consists of 1008 amino acids (aa) with a molecular weight of 113 kDa. X. laevis PARP shares 74, 83, 73, 78 and 42% aa sequence homology with the human, bovine, mouse, chicken and Drosophila melanogaster PARPs, respectively. Comparison of the PARP aa sequences among these species showed conservation of two zinc-finger motifs in the DNA-binding domain, and an NAD-binding motif and a Rossmann fold in the catalytic domain. The first Leu of the putative leucine zipper of D. melanogaster PARP is substituted to Lys in X. laevis PARP. All the Glu residues in the leucine zipper are conserved in these six species.

Quantitation of HTLV-I provirus among seropositive blood donors: relation with antibody profile using synthetic peptides

To study the pathophysiological state of HTLV-I carriers and the quantitative aspect of the risk of HTLV-I infection, we measured the absolute amounts of HTLV-I provirus in 39 seropositive blood donors. The amount of provirus varied from less than one to more than 10(4) molecules per 10(5) peripheral-blood mononuclear cells (PBMC). The average amount of HTLV-I provirus among seropositive blood donors was estimated as 3.7 x 10(3) molecules per 10(5) PBMC. The titer of the antibody against only the synthetic peptide (aa 100 to 130) of the gag p19 region of the HTLV-I provirus showed a weak but significant correlation with the amount of the provirus.

HTLV-1-associated myelopathy/tropical spastic paraparesis-like rats by intravenous injection of HTLV-1-producing rabbit or human T-cell line into adult WKA rats

We intravenously injected Ra-1 cells or MT-2 cells into female adult WKA rats. Spastic paraparesis mainly in the hind-limbs was observed in 1 out of 2 Ra-1 cell-injected WKA rats and in 3 out of 8 MT-2 cell-injected WKA rats 20-27 months after injection. The main neuropathological finding was symmetrical white matter degeneration with mononuclear cell infiltration of the spinal cord, similar to that of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients, and degeneration of nerve roots and peripheral nerves. Antibodies against HTLV-1 antigens were detected in plasma and cerebrospinal fluid from these HAM/TSP-like rats. HTLV-1 provirus was detected from the peripheral blood mononuclear cells of one of these rats 20 months after injection. Interestingly, spastic paraparesis was not observed in F344 rats.

Isolation of cDNAs encoding the catalytic domain of poly(ADP-ribose) polymerase from Xenopus laevis and cherry salmon using heterologous oligonucleotide consensus sequences

We have isolated and sequenced cDNAs encoding the catalytic domain of poly(ADP-ribose) polymerase (PARP) from Xenopus laevis and Oncorhyncus masou (cherry salmon). The cDNAs were amplified by polymerase chain reaction using heterologous oligonucleotides corresponding to the conserved sequences of mammalian cDNAs as primers. The deduced amino acid sequences of Xenopus laevis and cherry salmon cDNA showed 84.4% and 75.6% similarities to that of human PARP, respectively. In both species, mRNA for PARP was identified as a single band of 4 kb, and PARP mRNA was abundant in ovary and brain. Thus, mixed oligonucleotide-primed amplification is a useful method in the cloning of cDNAs from different species, and the catalytic domain of PARP is conserved structurally among phylogenetically different species, suggesting an importance of poly(ADP-ribosyl)ation.

Vertical transmission of HTLV-1 in HTLV-1 carrier rat

A female F344 rat was injected with 2.4 x 10(6) MT-2 cells intravenously at 3 and 4 weeks old, and was mated with a non-infected male rat at the 17th week after injection, when the dam rat contained HTLV-1 provirus in the peripheral blood mononuclear cells as determined by polymerase chain reaction. HTLV-1 provirus was detected in at least 2 out of 9 offspring. This system should be useful for studies on the routes and prevention of vertical transmission and on elimination of once-transmitted HTLV-1.

A simple and reliable method for the detection and quantitation of the human T-cell leukemia virus type-I provirus in peripheral blood mononuclear cells of seropositive blood donors

Human T-cell leukemia virus type I (HTLV-I) antibody detection has been widely used to screen HTLV-I carriers. Sometimes, however, it gives false positive or negative results. A demonstration of the HTLV-I provirus from patients' peripheral blood mononuclear cells (PBMC) should, therefore, give the crucial evidence for them being HTLV-I carriers. We established a simple and reliable method using the polymerase chain reaction (PCR) to detect one molecule of HTLV-I provirus in 100 x 10(3) PBMC, during which internal control primers for the human beta-globin gene were also employed in the same reaction tube to check the success of the amplification reaction. We can thus easily avoid any false negative judgement and quantitate the HTLV-I provirus in PBMC simply by diluting the sample before PCR. One ml blood was enough for ten or more determinations by PCR. Analysis of seropositive blood from donors demonstrated a wide range for the number of HTLV-I provirus in PBMC. The method could conveniently be used for quantitating HTLV-I proviruses and following up HTLV-I carriers to study the pathophysiology and mode of HTLV-I transmission.

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.