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Biomedical subjects

M Smith

Publications and source records attributed to M Smith.

At least 1,261 records · Page 70Linked to original sources
PubMed1980

Applications of synthetic oligodeoxyribonucleotides to problems in molecular biology.

The applications of synthetic oligodeoxyribonucleotides to problems in molecular biology described in this article are those where the oligodeoxyribonucleotide is a probe for a specific region of a nucleic acid. This includes the isolation of the iso-1-cytochrome c gene of yeast; the sequence determination of RNAs and DNAs including regions of double-stranded DNA; the introduction of defined site-specific point mutations into bacteriophage OX174 and in the in vitro selection of mutant DNA from a mixture with wild-type DNA.

Base Sequence↗
PubMed1980

Serum beta-2-microglobulin: an adjunctive monitoring test in renal transplantation.

We have serially measured serum beta 2 M microglobulin in a series of transplant recipients along with other standard clinical parameters. Independent comparison of the beta 2 M results leads to the following conclusions: 1. Beta 2 M is superior to the Scr in detecting acute rejection, with diagnostic elevations occurring 2 to 7 days before Scr increase. The observation is valid for all rejection episodes. 2. Beta 2 M decreases prior to or simultaneously with the Scr following successful rejection therapy or beginning resolution of acute tubular necrosis. 3. Abnormal beta 2 M following rejection therapy invariably heralds another rejection episode within 10-20 days, despite the Scr having returned to baseline. 4. Beta 2 M remains normal in high grade ureteral obstruction despite increased Scr. 5. Beta 2 M is remarkably increased in patients with viremia, despite minimal change in Scr. Beta 2 M remains normal in lower UTI from bacterial origin. Beta 2 M appears to be a major contribution in the monitoring of the renal transplant recipient which may have significant impact on therapeutic decisions in the future. In addition, it provides a reliable in vitro parameter which can be used to further assess specific treatment variables in a prospective controlled protocol approach.

Antilymphocyte Serum↗
PubMed1980

Azathioprine in primary biliary cirrhosis: a preliminary report of an international trial.

The effects of azathioprine on the course of primary biliary cirrhosis were studied prospectively in a multinational, double-blind randomized clinical trial involving 236 patients, of which 124 received azathioprine and 112 placebo. No significant effects were seen on survival, clinical course, hepatic histologic features, hepatic tests, or immunologic abnormalities after a median follow-up period of 18 mo, but most of the trends observed were in favor of azathioprine. The results obtained so far indicate that the effect of azathioprine as a single treatment is limited and probably of little clinical importance, but more years of follow-up will be needed to provide a definite conclusion.

Actuarial Analysis↗
PubMed1979

RNA synthesis and RNA polymerase activities in germ cells of developing rainbow trout testis.

Spermatogenesis is a complex developmental process which sequentially generates several different germ cell types. These cell types from rainbow trout (Salmo gairdnerii) testis were separated by sedimentation in serum albumin gradients and characterized on the basis of their physical properties, chronological appearance, and protein synthesis. The rate of RNA synthesis, the types of RNA made, and the RNA polymerase activities present were determined for each cell type. The rate of RNA synthesis decreased from a high level in spermatogonia and spermatocytes to a low level in early spermatids and was absent in late spermatids and mature spermatozoa. Newly synthesized RNA in spermatogonia and spermatocytes consisted of a variety of molecular weight species, including 18 S and 28 S ribosomal RNAs. The synthesis of high molecular weight RNAs, especially ribosomal RNAs, decreased drastically in early spermatids, leading to the synthesis of only small molecular weight RNAs. RNA polymerase I and II were present in all cell types but the activities of both showed large decreases between spermatocytes and middle spermatids. Both RNA polymerase activities were almost absent from spermatozoa. The activities of RNA polymerase I and II from unfractionated testis cells at different stages of hormone-induced spermatogenesis were quantitated by fractionation of the solubilized extract on DEAE-cellulose. Both polymerases showed major decreases in activity which began near the chronological mid-point of development. For polymerase I the decrease in activity was over 400 fold, for polymerase II over 200 fold. The number of RNA polymerase II molecules per testis cell, quantitated by the binding of [3H]amanitin to cell extracts, also decreased markedly during spermatogenesis. The reduction in polymerase II activity was accompanied by a parallel 200-fold decrease in[3H]amanitin binding. The reduction in polymerase activity appears, therefore, to be due to an actual reduction in the cellular content of RNA polymerase II molecules. These results suggest that transcription in maturing testes is regulated, at least in part, by the concentrations of the RNA polymerases.

Amanitins↗
PubMed1979

[A dominant form of pseudoachondroplastic dysplasia. A familial case (author's transl)].

The authors report a family of 5 subjects suffering from pseudoachondroplastic dysplasia in an autosomal dominant form. The interest of this report lies in the radiological documents obtained in the subjects at different ages (3, 18 and 63 years) and the extreme rarity of autosomal dominant forms since only six familial cases of this type have been described up to the present time.

Achondroplasia↗
PubMed1979

Defined transversion mutations at a specific position in DNA using synthetic oligodeoxyribonucleotides as mutagens.

The oligodeoxyribonucleotides, pCCCAGCCTCAA, which is complementary to nucleotides 5274--4284 of bacteriophage phi X174 viral DNA , and pCCCAGCCTAAA, which corresponds to the same sequence with a C leads to A change at the ninth nucleotide, were synthesized enzymatically. The second of these oligonucleotides was used as a primer for E. coli DNA polymerase I, from which the 5'-exonculease has been removed by proteolysis (Klenow enzyme), on wild-type phi X174 viral DNA template. After ligation, this yielded closed circular heteroduplex DNA with a G, A mismatch at nucleotide 5276. Transfection of E. coli spheroplasts with the heteroduplex DNA produced phage mutated at this nucleotide (G leads to T in the viral DNA) with high efficiency (13%). The mutant DNA, which corresponds to the gene B mutant am16, was reverted (T leads to G) by the wild type oligonucleotide with an efficiency of 19%. The nucleotide changes were established by sequence determination of the mutated viral DNA using the enzymatic terminator method. The production of specific transversion mutations, together with a previous demonstration of specific transition mutations (1), established that short enzymatically synthesized oligodeoxyribonucleotides can be used to induce any class of single nucleotide replacement with high efficiency and thus provide a powerful tool for specific genetic manipulations in circular genomes like that of phi X174.

Bacteriophage phi X 174↗