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Biomedical subjects

S Silverman

Publications and source records attributed to S Silverman.

At least 217 records · Page 12Linked to original sources
PubMed1978

Nucleotide sequence of phenylalanine transfer RNA from Schizosaccharomyces pombe: implications for transfer RNA recognition by yeast phenylalanyl-tRNA synthetase.

The nucleotide sequence of Schizosaccharomyces pombe tRNAPhe was determined to be pG-U-C-G-C-A-A-U-G**-G*-U-G-psi-A-G-D-D-G-G-G-A-G-C-A-psi-G*-A-C-A-G-A-Cm-U-Gm-A-A-Y-A-psi-m5C-U-G-U-U-G-m7G-U*-C-A-U-C-G-G-T-psi-C-G-A-U-C-C-C-G-G-U-U-U-G-U-G-A-C-A-C-C-AOH. This sequence differs from that of S. cerevisiae tRNAPhe in 27 nucleotides. Saccharomyces cerevisiae phenylalanyl-tRNA synthetase aminoacylates both the homologous tRNAPhe and S. pombe t-NAPhe; the reactions have similar Km and Vmax values. However, the nucleotide sequence in the D stem is different in the two tRNAs. This region was proposed by Roe, B., et al. [(1973) Biochemistry 12, 4146--4154] to be the major recognition site for yeast phenylalanyl-tRNA synthetase, but the present results cast doubt on the validity of this hypothesis.

Amino Acyl-tRNA Synthetases↗
PubMed1978

Effects of therapeutic radiation on microstructure of the human mandible.

Mandibular bone from eight patients who had received therapeutic radiation (6,000-7,200 rads) for intra-oral cancer was obtained at surgery (1 month to 9 years after radiation) and compared histologically with non-irradiated mandibular bone from five subjects. Measurements made on the internal remodeling process of cortical bone included the extent of internal surface and the fraction indicating resorption, and the proportions of osteones which were incomplete (less than 3/4 filled with matrix), complete, and plugged. Appreciable differences were observed in all parameters except plugged osteones. The findings suggested early cessation of osteogenesis, and somewhat later cessation of resopriton, without subsequent resumption of either process. The histologic appearance of the osteoblasts, osteoclasts, and osteones was in accord. Microfractures found in the irradiated bone were not seen to have healed. Radiation damage to the osteoprogenitor cells is postulated.

Adult↗
PubMed1978

Erythema multiforme. Clinical characteristics and natural history in fifty patients.

Erythema multiforme is a chronic mucocutaneous inflammatory disease with a variable recurrent pattern. Thirty female and twenty male patients, ranging in age from 11 to 75 years, were studied. Twelve patients had oral lesions only, nineteen had oral and lip changes, and nineteen had oral, lip, and skin involvements. Most of the patients had a noncyclical pattern of attacks which required systemic corticosteroid therapy. When the disease attacks electively were not treated, healing would vary between 2 and 24 weeks. This study confirmed the idiopathic nature and extremely variable features of erythema multiforme. Frequency, location, duration, and severity of attacks did not shed any clues as to trigger mechanisms (etiology), persons who might be predisposed to such attacks, treatment responses, or prognosis.

Adolescent↗
PubMed1978

Specific transcription of eukaryotic tRNA genes in Xenopus germinal vesicle extracts.

Cloned tRNA genes from Drosophila and from yeast have been transcribed faithfully in extracts prepared from Xenopus germinal vesicles. The newly formed RNA is composed of precursor tRNAs (of 5S RNA size) and of tRNAs. The plasmid pCIT12 carries genes for Drosophila tRNALys, tRNAArg, and tRNAAsn, Nucleotide analysis of one RNA species transcribed from pCIT12 DNA showed it to be identical to Drosophila tRNALys; it even contained some of the modified nucleotides expected for this tRNA. This RNA species is formed in the germinal vesicle extract via a larger precursor tRNA molecule that does not contain nucleotide modifications. This simple transcription system should aid studies aimed at defining the regulatory DNA regions responsible for eukaryotic gene transcription. In addition, it may provide tRNA precursors that are needed for detailed investigations of eukaryotic tRNA biosynthesis.

Animals↗
PubMed1978

Double-blind study of levamisole therapy in recurrent aphthous stomatitis.

Forty-eight patients with diagnosed recurrent aphthous stomatitis participated in a randomized double-blind study of levamisole therapy. Each patient's response to treatment was determined by the following criteria: (1) days between attacks, (2) duration of lesions, (3) patient's self-evaluation of pain, (4) investigator's clinical evaluation of patient's subjective treatment response. Statistical analysis of the levamisole and placebo groups of criteria 1 and 2 above revealed no significant difference. In contrast to the above findings, analysis of the investigator's recordings of patient's subjective treatment response showed that 26% of the levamisole patients experienced marked or moderate improvement. None of the placebo patients were recorded as having experienced the same degree of benefit. Fourteen of 15 patients who complained of side effects were taking levamisole. The most common side effects were dysgeusia and hyperosmia.

Clinical Trials as Topic↗
PubMed1978

Splenic disease.

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Animals↗
PubMed1978

A case study of canine panosteitis: comparison of radiographic and radioisotopic studies.

A dog with recurrent active panosteitis was monitored with weekly skeletal radiographs and radioisotopic bone scintigrams performed on the same day. Comparison of results obtained by the two techniques indicated that scintigrams were more sensitive in revealing early lesions. Radiography was more specific and essential to establish a positive diagnosis. The sensitivity of radiographic and scintigraphic evidence was comparable during the midportions of the disease while bone resorption and deposition were most active. In late stages of panosteitis, after disappearance of clinical signs, the scintigrams were negative, whereas radiographs continued to reveal the presence of sclerotic lesions.

Animals↗
PubMed1978

Radiation safety.

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Accident Prevention↗
PubMed1977

An epilogue to plasma-cell gingivostomatitis (allergic gingivostamtitis).

Sixteen cases of plasma-cell gingivostomatitis were studied at the University of California San Francisco between 1966 and 1971. Twelve women and four men made up the group, with ages ranging from 15 to 70 years. Prior to treatment, the duration of the disease ranged from 5 to 60 months. Each of the sisteen patients manifested a homogeneous, diffuse, erythematous gingivitis associated with a cheilitis, and fifteen also had a marked glossitis. Each subject was symptomatic, and nine also complained of bleeding. Every biopsy specimen demonstrated a characteristically diffuse and dense plasma-cell infiltrate. There were no spontaneous remissions. Six patients completely responded to systemic corticoids alone, two to discontinuation of gum chewing or the use of their dentifrice, one to antifungal therapy, and the other seven to a combination of the preceding modalities. After completion of therapy, fifteen patients were followed for 2 to 55 months without any evidence of recurrence. Of interest, 69 per cent were gum chewers. The therapeutic benefit of discontinuing gum chewing by itself was not clear. It is assumed that the now nonexistent plasma-cell gingivostomatitis syndrome was a hypersensitivity response to an unidentifiable antigen used in various substances.

Adolescent↗
PubMed1977

A rapid method for preparation of calf spleen exonuclease.

Chromatography on Concanavalin A sepharose is a simple procedure for partial purification of spleen phosphodiesterase. This procedure removes much, but not all, of the ribonuclease activity found as contaminant in most spleen phosphdisterase preparations.

Animals↗
PubMed1977

Radiographic diagnosis of choanal atresia induced prenatally with triamcinolone in the baboon (Papio cynocephalus).

Choanal atresia was diagnosed radiographically using a water soluble contrast media in 2 of 7 Papio cynocephalus exposed to triamcinolone acetonide in utero. In one P. cynocephalus, the atresia was complete and was associated with other orofacial abnormalities. The other animal, previously considered to be normal, had a partial nasal obstruction. The radiographic appearance of the drug-induced defects observed in the baboon closely resemble the descriptions of spontaneously occurring defects in human infants.

Animals↗