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Biomedical subjects

L Silver

Publications and source records attributed to L Silver.

At least 73 records · Page 4Linked to original sources
PubMed1979

Tn10 mediated integration of the plasmid R100.1 into the bacterial chromosome: inverse transposition.

Upon integration into the bacterial chromosome the drug resistance plasmid R100.1 often loses its tetracycline resistance character. We have analyzed an Hfr strain formed by such an integration and an R-prime plasmid derived from it. We find that integration took place within the Tn10 transposon, that the two IS10 sequences were retained, but that at least 80% of the transposon segment located between them, and carrying the tetracycline resistance genes, had been lost. We suggest that integration of R100.1 was mediated by an inverse transposition using the IS10 sequences.

Chromosomes, Bacterial↗
PubMed1979

Erroneous thyroid-stimulating hormone radioimmunoassay results due to interfering antibovine thyroid-stimulating hormone antibodies.

Apparent elevation of serum thyroid-stimulating hormone (TSH) levels was found in a case of a patient receiving adequate replacement therapy after thyroidectomy for a follicular carcinoma. This was an artifact due to interference with the radioimmunoassay by circulating antibovine TSH antibodies. The double-antibody technic showed spuriously elevated levels, and the single-antibody technic showed low levels of serum TSH by radioimmunoassay in the presence of antibodies.

Animals↗
PubMed1978

Hypertrophic Riedel's lobe of the liver.

Riedel's lobe, noted on 99mTc-sulfur colloid liver scintigraphy, was present in 86 (3.3%) of 2604 patients reviewed. Hypertrophied Riedel's lobe was found in 30 cases of which 25 (83%) were females and 5 (17%) were males. Liver scintigraphy will detect the presence of a hypertrophied Riedel's lobe and is recommended in all cases of right sided abdominal masses.

Abdominal Neoplasms↗
PubMed1978

Bone scan in sickle cell crisis.

99mTc-diphosphonate bone scans of 13 patients in acute sickle crisis were analyzed. Twelve of the 13 patients had abnormal scans, with increased activity in joints and skull being a common finding. One patient with splenic calcification and two patients without splenic calcification had splenic uptake of diphosphonate. Most of the abnormal scans showed hot areas, with cold areas seen only in four cases. There was no correlation between the site of pain clinically and the abnormal areas on scanning. The pathophysiology of the abnormal uptake of radioactivity and the role of bone scanning on sickle cell disease are discussed.

Acute Disease↗
PubMed1977

Modification of impulsive tempo in learning-disabled pupils.

Thirty-three impulsive learning-disabled males, aged 9-12 years, were assigned to one of three treatment conditions: (a) Modeling, in which subjects were exposed to a videotape of a boy demonstrating reflective problem-solving activities and instructing himself to perform cautiously; (b) Modeling Plus Self-Verbalization, in which subjects observed the same videotape and were additionally required to verbalize similar reflective instructions; and (c) Control, in which subjects were shown a videotape of the task materials used in the modeling videotape, but without the model. Subjects were tested immediately after exposure to treatment, and again 3 weeks later, on different forms of the Matching Familiar Figures test. Both Modeling and Modeling Plus Self-Verbalization conditions were superior to Control in reducing errors on the immediate test, but the three treatments did not differ on the delayed test. No significant differences among the three conditions were found with regard to response latency. Discrepancies between the present results and those of previous related studies were noted, and potential research directions were suggested.

Behavior Therapy↗
PubMed1977

Suppression of an Escherichia coli dnaA mutation by the integrated R factor R100.1: generation of small plasmids after integration.

We have observed that integration of the R plasmid R100.1 into the chromosome of Escherichia coli is associated with the formation of small, covalently closed circular elements. Contour length measurements, partial denaturation mapping, and analysis of the deoxyribonucleic acid fragments produced by digestion of one of these, pLC1, with the restriction endonuclease EcoRI indicate that it is the r-determinant element of R100.1.

Chromosomes, Bacterial↗
PubMed1977

Suppression of an Escherichia coli dnaA mutation by the integrated R factor R100.1: origin of chromosome replication during exponential growth.

We have investigated the behavior, during exponential growth, of strains of Escherichia coli carrying a dnaA(Ts) mutation that has been suppressed by the integration of the F-like R plasmid R100.1. We present evidence showing that replication in these strains proceeds largely from the normal chromosome origin at 30 degrees C, a permissive temperature for the dnaA(Ts) gene product, whereas, at 42 degrees C, replication proceeds largely from the integrated plasmid. These conclusions are based on measurements made by deoxyribonucleic acid:deoxyribonucleic acid hybridization of the relative frequencies of the prophages Mu-1 and lambdaind- and R100.1 integrated at known locations on the E. coli chromosome in these Hfr strains.

Chromosome Mapping↗
PubMed1977

Origin and direction of replication of the drug resistance plasmid R100.1 and of a resistance transfer factor derivative in synchronized cultures.

The origin and direction of replication of the resistance plasmid R100.1 and its resistance transfer factor derivative, pAR132, were studied by electron microscopy autoradiography of partially denatured molecules and partial denaturation mapping of replicative intermediates. Results of these studies indicate the existence of an origin of replication at 8.8 kilobases on the R100 map. Replication from this origin in cultures synchronized for initiation of replication is predominantly unidirectional in a single direction.

Amino Acids↗
PubMed1975

Diagnosis of chronic and postoperative osteomyelitis with gallium 67 citrate scans.

The effectiveness of gallium 67 citrate in diagnosing the exacerbations of chronic osteomyelitis or postoperative osteomyelitis secondary to open reduction of fractures was tested in thirteen patients. This isotope demonstrated an area of infection in every case in which such an area existed. The control subjects consisted of patients with noninfected wounds after open reduction. In this group, gallium was not incorporated into the post-operative hematoma. No false-negative results were observed in our series, demonstrating that this element is useful in the early diagnosis of bone infections.

Adult↗
PubMed1974

Clinical infections detected by 67Ga scanning.

Gallium-67 was utilized in 34 patients suffering from clinically demonstrable infections. The isotope was able to localize infections in soft tissue, bones, and some areas of the abdomen. Its utilization in the diagnosis of pelvic inflammatory disease is complicated by the fact that the isotope is secreted into the bowel and obscures the area. This isotope is ideal for the diagnosis of acute and/or chronic inflammation of bone secondary to open reduction of fractures, and may also be of use in the diagnosis of primary osteomyelitis.

Abscess↗