Solid-phase, single nucleotide primer extension of DNA/RNA hybrids by reverse transcriptases.

A method for RNA analysis based on primer extension by reverse transcriptase is described.

Wardium paucispinosum sp. n. (Eucestoda: Hymenolepididae), parasite of Larus maculipennis (Aves: Laridae) in Mar del Plata, Argentina; with comments on Wardium semiductilis (Szidat, 1964) comb. n.

A new species Wardium paucispinosum (Eucestoda: Hymenolepididae) parasite from the intestine of Larus maculipennis (Lichtenstein) from Mar del Plata, Argentina is described. The distinctive features of the new species are: strobilar length 52.8 mm; 10 aploparaksoid rostellar hooks, 14 (12-17) microm long; ratio between cirrus pouch length and mature proglottid width (CPL/MPW) 0.38 (0.27-0.50); regular cylindrical evaginated cirrus, 90 x 10 microm, with distal end without spines and proximal and medium thirds covered with spines 7 microm long; simple tubular membranous vagina, 110 x 10 microm, without sclerotised portions and sphincters; eggs fusiform, 77 x 44 microm. Besides, Hymenolepis semidutctilis Szidat, 1964, from the intestine of Larus dominicanus and L. maculipennis from Santa Fe, Argentina is transferred to the genus Wardium Mayhew, 1925, based on the presence and shape of the rostellar hooks.

Inhibition of the tissue factor-thrombin pathway limits infarct size after myocardial ischemia-reperfusion injury by reducing inflammation.

Functional inhibition of tissue factor (TF) has been shown to improve coronary blood flow after myocardial ischemia/reperfusion (I/R) injury. TF initiates the coagulation protease cascade, resulting in the generation of the serine protease thrombin and fibrin deposition. Thrombin can also contribute to an inflammatory response by activating various cell types, including vascular endothelial cells. We used a rabbit coronary ligation model to investigate the role of TF in acute myocardial I/R injury. At-risk areas of myocardium showed increased TF expression in the sarcolemma of cardiomyocytes, which was associated with a low level of extravascular fibrin deposition. Functional inhibition of TF activity with an anti-rabbit TF monoclonal antibody administered either 15 minutes before or 30 minutes after coronary ligation reduced infarct size by 61% (P = 0.004) and 44% (P = 0.014), respectively. Similarly, we found that inhibition of thrombin with hirudin reduced infarct size by 59% (P = 0.014). In contrast, defibrinogenating the rabbits with ancrod had no effect on infarct size, suggesting that fibrin deposition does not significantly contribute to infarct size. Functional inhibition of thrombin reduced chemokine expression and inhibition of either TF or thrombin reduced leukocyte infiltration. We propose that cardiomyocyte TF initiates extravascular thrombin generation, which enhances inflammation and injury during myocardial I/R.

Measurement of tissue factor activity in whole blood.

High circulating levels of the procoagulant molecule tissue factor (TF) are associated with thrombosis in a variety of diseases including unstable angina, cancer, and sepsis. Currently, there are no clinical assays to measure the level of TF activity in whole blood. We present an assay called Tissue Factor Clotting Time ("TiFaCT") that detects fibrin formation in human blood. The mean baseline clotting time in a healthy population was 472 +/- 94 s (mean +/- SD, n = 150). Bacterial lipopolysaccharide (LPS or endotoxin) shortened the clotting time in a time-dependent manner. Inhibitory anti-TF antibodies prolonged the clotting time of LPS-stimulated blood, indicating that the shortened clotting time was due to induction of TF expression. Patients with unstable angina had shortened mean baseline clotting time (284 +/- 86, n = 13) compared with healthy volunteers (474 +/- 98, n = 30), suggesting that these patients had elevated levels of circulating TF. The TiFaCT assay should prove clinically useful in quantifying the levels of circulating TF in patients at risk of thrombosis.

Unexpectedly long 14S ribosomal RNA gene in Tetrahymena mitochondria.

Extraction of RNA from Tetrahymena mitochondrial ribosomes yields several RNA species, including a "large" 21S molecule, a "small" 14S molecule, a 7S molecule, and other smaller RNAs. The molecular weight of the 14S rRNA indicates that it is about 1,300 bases in length. We have sequenced the 14S rRNA gene and, by aligning our sequence with that of the corresponding small rRNA from E. coli, find that the 14S rDNA is at least 1,635 bases in length. We propose, based on the results of hybridization studies, that this unexpected length is due to the presence of 7S RNA sequence within the 14S gene sequence. The 7S region is apparently lost from the 14S rRNA, yet is still a component of the ribosome.

Initiation of auxin autonomy in Nicotiana glutinosa cells by the cytokinin-biosynthesis gene from Agrobacterium tumefaciens.

Agrobacteria carrying mutations at the auxin-biosynthesizing loci (iaaH and iaaM of the Ti plasmid) induce shoot-forming tumors on many plant species. In some cases, e.g. Nicotiana glutinosa L., tumors induced by such mutant strains exhibit an unorganized and fully autonomous phenotype. These characteristics are stable in culture at both the tissue and cellular level. We demonstrate that the cytokinin-biosynthesis gene (ipt) of the Ti plasmid is responsble for the induction of both auxin and cytokinin autonomy in N. glutinosa. Cloned cell lines carrying an ipt gene but lacking iaaH and iaaM are capable of accumulating indole-3-acetic acid. Interestingly, non-transformed N. glutinosa tissues exhibit an auxin-requiring phenotype when they are grown on medium supplemented with an exogenous supply of cytokinin. These results strongly indicate that exogenously supplied cytokinin does not mimic all the effects of the expression of the ipt gene in causing the auxin-autonomous growth of N. glutinosa cells.

The microbiologic flora of orofacial abscesses.

Fifty orofacial abscesses were studied using culture techniques for both aerobic and anaerobic organisms. Eighty-six per cent of the specimens contained anaerobes; of this group, 39 per cent had organisms resistant to penicillin.