Movement and guidance of migrating mesodermal cells in Ambystoma maculatum gastrulae.

A scanning electron microscopic study in early gastrulae of Ambystoma maculatum showed that migrating presumptive mesodermal cells were strongly oriented toward the animal pole. They had lamellipodia and filopodia at their leading edges, and rounded or tapering, tail-like, trailing edges. Of the cells whose polarization could be determined unequivocally, 81% appeared to be directed in a quadrant toward the animal pole, and 93% were directed to some extent away from the blastopore.

Cucumber mosaic virus RNA 3. Determination of the nucleotide sequence provides the amino acid sequences of protein 3A and viral coat protein.

The complete sequence of the 2193 residues of RNA 3 (Mr 746000) of cucumber mosaic virus (Q strain) was determined by a combination of chemical and enzymic sequencing techniques utilizing cloned DNA fragments. The nucleotide sequence of RNA 3 also gave the complete sequence of 1027 residues of RNA 4 (Mr 349000), which codes for the viral coat protein and is derived from the 3' end; there are 53 untranslated nucleotides at the 5' end of RNA 4. The nucleotide sequence provided the amino acid sequences of the two proteins coded for by RNA 3: the 5'-terminal 3A protein with 333 amino acids (Mr 36700) and the 3'-terminal viral coat protein with 236 amino acids (Mr 26200).

Dynamic and biochemical responses to single and repeated doses of clonidine during dynamic physical activity.

Beta-adrenoceptor blockade increases serum K, which may be related to renin inhibition, hypoaldosteronism, and exercise-induced skeletal muscle release of serum K. We report on the dynamic and biochemical response to clonidine (C) after single (S) 0.2-mg and repeated (R) 0.

Interaction of purified DNA with plant protoplasts of different cell cycle stage: The concept of a competent phase for plant cell transformation.

The polycation mediated attachment of purified tritiated DNA to plant protoplasts has been measured by quantitative microautoradiography. The automated grain counting technique used, also provides information on the cell cycle stage of individual protoplasts, which circumvents the need to synchronize the plant cell population before preparation of protoplasts. With protoplasts from asynchronously dividing suspension cultures of Nicotiana syhestris (NS-1), S-phase protoplasts appear to be inefficient binders of (3)H-DNA, as compared with G1 or G2 protoplasts.

Studies on encapsidated viroid-like RNA. IV. Requirement for infectivity and specificity of two RNA components from velvet tobacco mottle virus.

Neither the virus-like RNA (RNA 1) nor the viroid-like RNA (RNA 2) of velvet tobacco mottle virus (VTMoV) is capable of independent replication in Nicotiana clevelandii. The function of RNA 2 for the RNA 1 replication could not be fulfilled by conventional viroids such as those of chrysanthemum stunt, citrus exocortis, or the viroid-like RNAs associated with avocado sunblotch and cadang-cadang disease of coconut. Similarly, RNA 2 failed to replicate when coinoculated with RNAs of conventional viruses such as those of southern bean mosaic, sowbane mosaic, galinsoga mosaic, red clover necrotic mosaic, and carnation mottle, all of which possess genomes with molecular weights similar to those of VTMoV RNA 1.

Immunochemical detection of ds-RNA in healthy and virus-infected plants and specific detection of viral ds-RNA by hybridization to labelled complementary DNA.

Double-stranded (ds) RNA was detected in nucleic acid preparations from virus-free leaf tissues of several plant species by radial double-diffusion tests with antiserum raised against polyinosinic : polycytidylic acid [poly(I) : poly(C)]. No significant differences in the concentrations of ds-RNA were detected by such tests in virus-free French bean leaves and those infected with tobacco mosaic virus or tobacco ringspot virus. However, virus-specific ds-RNAs as well as genomic RNAs of both viruses were readily detected and estimated quantitatively by hybridization to 3H-labelled complementary DNA probes.

Studies on encapsidated viroid-like RNA. III. Comparative studies on RNAs isolated from velvet tobacco mottle virus and Solanum nodiflorum mottle virus.

Solanum nodiforum mottle virus (SNMV) encapsidates two unique RNA species as shown by 3H-complementary DNA hybridization analysis. They are RNA 1, a long linear single-stranded molecule with a molecular weight of 1.5 x 10(6) and RNA 2 and RNA 3 which are circular and linear forms of the same molecule, respectively.

Microfibrillar collagen and dehydrated dura xenografts for the closure of oroparanasal communications.

Dehydrated dura mater and a microfibrillar collagen preparation were used in a previously described experimental animal model system for the repair of oroparanasal communications. The clinical and histologic findings are discussed. Results support the reproducibility of the original animal model system.

The bipartite genome of red clover necrotic mosaic virus.

Purified preparations of red clover necrotic mosaic virus isolated in Australia have been shown to contain three RNA components whose electrophoretic mobilities in polyacrylamide gel electrophoresis indicate molecular weights of 1.5 x 106 (RNA 1), 0.5 x 10(6) (RNA 2), and 0.

Studies on encapsidated viroid-like RNA. II. Purification and characterization of a viroid-like RNA associated with velvet tobacco mottle virus (VTMoV).

A viroid-like RNA has been purified from velvet tobacco mottle virus (VTMoV) capsids. This RNA exists as a covalently closed circular molecule of RNA as well as in a linear form with a molecular weight of approximately 1.2 x 10(5).

Studies on encapsidated viroid-like RNA I. Characterization of velvet tobacco mottle virus.

Velvet tobacco mottle virus (VTMoV) isolated from Nicotiana velutina growing wild in arid Central Australia was transmitted by inoculation to a limited number of plant species of which N. clevelandii was the most convenient experimental host. The virus was also transmitted from field-grown plants toN.

Symmetrical gingival fibromatosis.

Symmetrical gingival fibromatosis, a rare and unusual form of idiopathic gingival fibrous hyperplasia, has recently been identified as a distinct clinical entity. The clinical and histologic features of a case of this disorder are presented. The relationship of this clinical entity to generalized gingival fibromatosis is considered, and the histologic findings in the present case are discussed.

A new approach to the analysis of clinical drug trials with withdrawals.

In clinical drug trials which require observation of patients for more than a few days or weeks, some patients may withdraw before completing the planned course of the trial for reasons that are related to the therapy, for example adverse experiences or lack of therapeutic effect. If the number of such withdrawals is material, then analysis of the data from these trials should account for these withdrawals. Ignoring them in the analyses or using the last recorded value before withdrawl can lead to misleading conclusions.

Interrelation of the renin system and erythropoietin in rats.

Evidence is presented implicating the renin-angiotensin system in the regulation of plasma erythropoietin concentration. Male and female rats were exposed to hypoxia at 0.43 atm for 8 hr.