Sites of right ventricular outflow tract obstruction in tetralogy of Fallot--a retrospective study

Fifty one angiographically proved cases of tetralogy of Fallot (TOF) in the age group of 5-50 years were analysed retrospectively for the level(s) of right ventricular outflow tract (RVOT) obstruction. Mean age was 18.1 +/- 11 yrs. Subvalvular stenosis was found to be the commonest site of RVOT obstruction in 49 (96.1%) patients. Evidence of valvular pulmonary stenosis was seen quite commonly (42/51, 83.9% cases), mostly in association with obstruction at other sites. Supravalvular stenosis was also seen in 17 (33.3%) cases. Higher incidence of pulmonary valvular involvement in patients with TOF, in higher average age of patient population may represent valvular involvement to be an acquired phenomenon.

Pharmacokinetics, biodistribution, and stability of oligodeoxynucleotide phosphorothioates in mice

We describe preliminary studies of the pharmacokinetics, biodistribution, and excretion of an oligodeoxy-nucleotide phosphorothioate ([S]oligonucleotide) in mice. After either intravenous or intraperitoneal administration of a single dose (30 mg/kg of body weight), [S]oligonucleotide (35S-labeled at each internucleotide linkage) was found in most of the tissues for up to 48 hr. About 30% of the dose was excreted in urine within 24 hr, irrespective of the mode of administration; the excreted [S]oligonucleotide was found to be extensively degraded. In plasma, stomach, heart, and intestine, the [S]oligonucleotide was degraded by only 15%, whereas in the kidney and liver degradation was about 50% in 48 hr. The surprising observation was made that chain length extension of administered [S]oligonucleotide occurred in kidney, liver, and intestine. These results provide an initial definition of parameters for the pharmaceutical development of antisense oligonucleotides.

Biotinylated antisense methylphosphonate oligodeoxynucleotides. Inhibition of spliceosome assembly and affinity selection of U1 and U2 small nuclear RNPs

Methylphosphonate (PC) backbone oligodeoxynucleotides complementary to the 5'-terminal nucleotides of U1 and U2 small nuclear (sn) RNAs do not elicit RNase H action under conditions in which natural (phosphodiester) oligodeoxynucleotides yield extensive RNase H cleavage. We show here that antisense PC oligonucleotides can mask sites in U1 and U2 snRNPs that are required for spliceosome formation. We further report that biotinylated derivatives of antisense PC oligos can be used for affinity selection of U1 and U2 snRNPs.

Site specific functionalization of oligonucleotides for attaching two different reporter groups

The synthesis of an oligonucleotide functionalized to attach two different reporter groups at specific internucleotide linkages is described. To incorporate the amine specific reporter group the internucleotide linkage is modified to phosphoramidate (N-1-aminoalkyl) and for a thiol specific reporter group the internucleotide linkage is modified to a phosphorothioate diester. The synthetic cycle for introducing the modified internucleotide linkages at specific sites can be carried out using an automated DNA synthesizer. Combination of reporter groups have been attached successfully.

Synthesis, purification, and characterization of 2,4,6-trinitrophenyl-UDP-galactose: a fluorescent substrate for galactosyltransferase

Glycosyltransferases enzymatically transfer monosaccharides from sugar-nucleotides to complex oligosaccharide chains and, as cell surface molecules, exhibit receptor-like activity. We have modified the substate UDP-galactose to produce a compound that has useful absorbance and fluorescence properties upon binding to galactosyltransferase (GalTase). Using strategies similar to those for preparing fluorescent ATP analogs, we were able to synthesize 2,4,6-trinitrophenyl-5'-UDP-galactose (TUG). In solution, the absorbance properties of TUG are pH dependent, with absorbance maxima at 260, 408, and 453 nm and an isobestic point at 353 nm. In the presence of soluble GalTase extracted from bovine milk, TUG exhibited an excitation maximum at 368 nm with emission maxima at 436 and 533 nm; in the absence of GalTase only the 533-nm peak was present. Under enzymatic conditions, TUG acted as a competitive substrate of UDP-galactose with GalTase. Under noncatalytic conditions, the fluorescence emission of TUG at 436 nm increased monotonically with Gal-Tase concentration, with a half-maximal response at approximately 4 microM. This compound may be useful for quantifying GalTase function as both an enzyme and a cell adhesion molecule.

Inhibition of influenza virus replication by phosphorothioate oligodeoxynucleotides

Oligodeoxynucleotides (ODNs) were synthesized and tested for their antiviral activity against influenza viruses. ODNs corresponded to the polymerase PB1 gene of either influenza A/WSN/33 virus or influenza C/JJ/50 virus. All compounds were 20 nucleotides long, including control ODNs containing mismatches. The phosphodiester ODNs (O-ODNs) failed to inhibit replication of influenza A and influenza C viruses at concentrations up to 80 microM, possibly due to intracellular nuclease digestion of the unmodified oligomers. By contrast, the phosphorothioate derivatives (S-ODNs) were found to inhibit replication of both influenza A and influenza C virus. The antiviral effect of S-ODNs against influenza A virus was found at concentrations as low as 1.25 microM and was present with mismatched oligomers. In the case of influenza C virus, the S-ODN complementary to the 3' end of the viral RNA of the PB1 gene revealed a sequence-specific antiviral activity at a concentration of 20 microM. (At the same concentration, S-ODNs with one or three mismatches showed little or no antiviral activity.) Reduction in plaque number reached six logarithms when this sequence-specific S-ODN was used at a concentration of 80 microM.

Preliminary observations on leukaemia specific agglutinins from seeds

Semipurified saline extracts of seeds from Crotolaria juncea, Cassia marginata, Ficus racemosa, Cicer arietinum (L-532), Gossipium indicum (G-27), Melia composita, Acacia lenticularis, Meletia ovalifolia, Acacia catechu and Peltophorum ferrenginium were tested for leukoagglutinating activity against whole leukocytes and mononuclear cells from patients with chronic myeloid leukaemia (34), acute myeloblastic leukaemia (5), acute lymphoblastic leukaemia (7), chronic lymphocytic leukaemia (3), various lymphoproliferative/haematologic disorders (54), and normal healthy subjects (50). In addition, bone marrow cells from three patients undergoing diagnostic bone marrow aspiration and activated lymphocytes from mixed lymphocyte cultures (MLC) were also tested. All the seed extracts agglutinated white blood cells from patients with different types of leukaemia. But none of them reacted with peripheral blood cells of normal individuals, patients with various lymphoproliferative/haematologic disorders or cells from MLC. Leukoagglutination of leukaemic cells with each of the seed extracts was inhibited by simple sugars. Only in one instance, cells from bone marrow of an individual who had undergone diagnostic bone marrow aspiration for a non-malignant condition were agglutinated. It is felt that purification of these seed extracts may yield leukaemia-specific lectins.

Echocardiographic demonstration of resolving intrapericardial mass in tuberculous pericardial effusion

A patient with tuberculous pericardial effusion is described who presented with cardiac tamponade. Subsequent to pericardiocentesis, a large echodense intrapericardial mass was observed which disappeared completely with antituberculous chemotherapy. The resolution of the mass suggests that it was a conglomeration of fibrinous exudates deposited in the pericardial cavity. Presence of such exudates should not be considered an indication for surgical intervention.

Site-specific excision from RNA by RNase H and mixed-phosphate-backbone oligodeoxynucleotides

Oligodeoxynucleotides containing phosphodiester or modified internucleoside linkages were investigated with respect to their ability to be acted on by ribonuclease H activities present in a HeLa cell nuclear extract after hybridization with complementary sequences in RNA. Oligodeoxynucleotides complementary to nucleotides 2-14 of human U1 small nuclear RNA were investigated. Extensive cleavage of U1 RNA was observed with the unmodified oligodeoxynucleotide and with the phosphorothioate analogue but not with U1-complementary oligodeoxynucleotides containing methylphosphonate, phosphoro-N-morpholidate, or phosphoro-N-butylamidate internucleoside linkages. Additional experiments using a 514-nucleotide-long RNA substrate demonstrated the capacity of complementary phosphodiester- and phosphorothioate-linked oligodeoxynucleotides (but not ones containing methylphosphonate, phosphoro-N-morpholidate, or phosphoro-N-butylamidate linkages) to serve as RNase H targets when hybridized to an internal RNA site. Detailed comparisons revealed phosphodiester-linked oligodeoxynucleotides to be more efficient than the comparable phosphorothioate-linked oligomers with respect to RNase H action. Various pentadecamer oligodeoxynucleotides complementary to the 514-nucleotide-long test RNA and containing 2-6 consecutive phosphodiester- or phosphorothioate-linked nucleotides flanked by RNase H-resistant methylphosphonate linkages afforded precise "site-directed" RNase H excision within the DNA.RNA hybrid. These results serve to assort modified oligodeoxynucleotide-containing hybrids into RNase H-sensitive and -resistant classes and also provide clues as to how RNase H makes contact with the DNA strand in a DNA.RNA hybrid.

Inhibition of human immunodeficiency virus in early infected and chronically infected cells by antisense oligodeoxynucleotides and their phosphorothioate analogues

Antisense oligodeoxynucleotides, both the phosphorothioate analogues and unmodified oligomers of the same sequence, inhibit replication and expression of human immunodeficiency virus already growing in tissue cultures of MOLT-3 cells with much greater efficacy than do mismatched ("random") oligomers and homooligomers of the same length and with the same internucleotide modification. This preferential inhibitory effect is elicited in as short a time as 4-24 hr postinfection. Likewise, antisense oligomers exhibit greater inhibitory effects on human immunodeficiency virus in chronically infected cells than do mismatched oligomers and homooligomers. Phosphorothioate antisene oligomers are up to 100 times more potent than unmodified oligomers of the same sequence in these inhibitory assays. These results, in major respects, confirm and extend those recently published by Matsukura et al. [Matsukura, M., Zon, G., Shinozuka, K., Robert-Guroff, M., Shimada, T., Stein, C. A., Mitsuza, H., Wong-Staal, F., Cohen, J. S. & Broder, S. (1989) Proc. Natl. Acad. Sci. USA 86, 4244-4248]. They also point out the importance of computer analysis of sequences though to be random but that in reality contain significant areas of likely hybridization, either to the viral genome or to the complementary DNA strand synthesized from it. They thus reinforce the concept that specific base pairing is a crucial feature of oligonucleotide inhibition of human immunodeficiency virus.

Detection of nucleic acid hybridization by nonradiative fluorescence resonance energy transfer

Three approaches were used to study hybridization of complementary oligodeoxynucleotides by nonradiative fluorescence resonance energy transfer. (i) Fluorescein (donor) and rhodamine (acceptor) were covalently attached to the 5' ends of complementary oligodeoxynucleotides of various lengths. Upon hybridization of the complementary oligodeoxynucleotides, energy transfer was detected by both a decrease in fluorescein emission intensity and an enhancement in rhodamine emission intensity. In all cases, fluorescein emission intensity was quenched by about 26% in the presence of unlabeled complement. Transfer efficiency at 5 degrees C decreased from 0.50 to 0.22 to 0.04 as the distance between donor and acceptor fluorophores in the hybrid increased from 8 to 12 to 16 nucleotides. Modeling of these hybrids as double helices showed that transfer efficiency decreased as the reciprocal of the sixth power of the donor-acceptor separation R, as predicted by theory with a corresponding R0 of 49 A. (ii) Fluorescence resonance energy transfer was used to study hybridization of two fluorophore-labeled oligonucleotides to a longer, unlabeled oligodeoxynucleotide. Two 12-mers were prepared that were complementary to two adjacent sequences separated by four bases on a 29-mer. The adjacent 5' and 3' ends of the two 12-mers labeled with fluorescein and rhodamine exhibited a transfer efficiency of approximately 0.60 at 5 degrees C when they both hybridized to the unlabeled 29-mer. (iii) An intercalating dye, acridine orange, was used as the donor fluorophore to a single rhodamine covalently attached to the 5' end of one oligodeoxynucleotide in a 12-base-pair hybrid. Under these conditions, the transfer efficiency was approximately 0.47 at 5 degrees C. These results establish that fluorescence modulation and nonradiative fluorescence resonance energy transfer can detect nucleic acid hybridization in solution. These techniques, with further development, may also prove useful for detecting and quantifying nucleic acid hybridization in living cells.

Inhibition of acquired immunodeficiency syndrome virus by oligodeoxynucleoside methylphosphonates

Antisense oligodeoxynucleotides containing internucleoside methylphosphonate linkages were examined for their ability to inhibit human immunodeficiency virus (HIV)-induced syncytium formation and virus expression. HIV inhibitory activity was found to be dependent on both chain length and the number of phosphonate residues. Introduction of 18 phosphonate groups in an oligomer of chain length 20 significantly increased HIV inhibitory activity relative to the parent oligonucleotide, whereas 5 such groups showed little or no increase in the HIV inhibition capacity. Methylphosphonate-linked oligomers are more stable to nuclease degradation and hence could be potentially useful in the treatment of acquired immunodeficiency syndrome.

Oligodeoxynucleoside phosphoramidates and phosphorothioates as inhibitors of human immunodeficiency virus

Modified oligodeoxynucleotides complementary to RNA of human immunodeficiency virus 1 (HIV-1) were tested for their ability to inhibit virally induced syncytium formation and expression of viral p24 protein. The modifications of oligomers include replacement of backbone phosphodiester groups with phosphorothioates and various phosphoramidates. All oligomers were found to be active. Oligomers with complete replacement of phosphodiesters with phosphoramidate or phosphorothioate groups were more active at the micromolar range than were unmodified oligomers of the same sequence. In addition, modified and unmodified homooligonucleotides also showed inhibition of HIV-1 replication. It is suggested that different classes of oligonucleotides may inhibit HIV replication by different mechanisms.

Inhibition of human immunodeficiency virus replication by antisense oligodeoxynucleotides

Twenty different target sites within human immunodeficiency virus (HIV) RNA were selected for studies of inhibition of HIV replication by antisense oligonucleotides. Target sites were selected based on their potential capacity to block recognition functions during viral replication. Antisense oligomers complementary to sites within or near the sequence repeated at the ends of retrovirus RNA (R region) and to certain splice sites were most effective. The effect of antisense oligomer length on inhibiting virus replication was also investigated, and preliminary toxicity studies in mice show that these compounds are toxic only at high levels. The results indicate potential usefulness for these oligomers in the treatment of patients with acquired immunodeficiency syndrome (AIDS) and AIDS-related complex either alone or in combination with other drugs.

In situ hybridization histochemistry: localisation of vasopressin mRNA in rat brain using a biotinylated oligonucleotide probe

A biotinylated antisense oligonucleotide probe specific for the glycopeptide sequence of arginine vasopressin mRNA has been used with amplified detection for visualisation of arginine vasopressin mRNA in the rat hypothalamus. RNAase pretreatment to destroy arginine vasopressin mRNA and use of excess complementary oligonucleotide (sense) to absorb the biotinylated antisense oligonucleotide demonstrated the reaction is specific for arginine vasopressin mRNA. Further, dehydration of rats using 2% saline resulted in an increase in specific staining. The staining is localized to those neurones in the hypothalamus known to contain arginine vasopressin.

Efficient methods for attaching non-radioactive labels to the 5' ends of synthetic oligodeoxyribonucleotides

The syntheses are described of two types of linker molecule useful for the specific attachment of non-radioactive labels such as biotin and fluorophores to the 5' terminus of synthetic oligodeoxyribonucleotides. The linkers are designed such that they can be coupled to the oligonucleotide as a final step in solid-phase synthesis using commercial DNA synthesis machines. Increased sensitivity of biotin detection was possible using an anti-biotin hybridoma/peroxidase detection system.

Antifertility effects of embelin in male rats

Embelin, extracted from Embelia ribes Burm. berries, altered the testicular histology and glycogen, gametogenic counts and accessory sex gland fructose at the dose levels 0.3, 0.4 and 0.5 mg/kg body weight administered subcutaneously for 35 days. The compound is suggested to possess antiandrogenic activity.

Synthesis, structure, and antitumor activity of N-salicyloyl-N'-(2-furylthiocarbonyl)hydrazine and its copper(II) complex

N-Salicyloyl-N'-(2-furylthiocarbonyl)hydrazine (H2sfth) and its Cu(II) complex [Cu(sfth)] were prepared and characterized by physicochemical studies. The IR and ESR spectral studies imply dibasic tetradentate behavior of the ligand bonding through "thiolo" sulfur, enolic oxygen, and hydrazinic nitrogens in a polymeric structure. The electronic spectrum of the complex indicates a square-planar geometry around Cu(II). Maximum antitumor activity was observed when 25 mg/kg dose levels of H2sfth and Cu(sfth) were injected intraperitoneally in mice bearing either solid fibrosarcoma or ascites Dalton's lymphoma. However, H2sfth appeared to possess better antitumor activity as demonstrated by higher T/C (percent) values than those observed for Cu(sfth). The appearance of lymphocytes, leukocytes, and macrophages within the tumor mass 2-6 days after treatment are indicative of involvement of the host's immune system.