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Biomedical subjects

B K Davis

Publications and source records attributed to B K Davis.

At least 55 records · Page 3Linked to original sources
PubMed1979

Eosinophilic pyeloureteritis: report of a case.

A case is reported of ureteral obstruction that was owing to eosinophilic pyeloureteritis, a previously unrecorded entity. The microscopic findings of extensive fibrosis and a relatively mild eosinophilic infiltrate were similar to those found in a series of eosinophilic cystitis, which was reported recently from this laboratory. Also, local injury appears to initiate some examples of eosinophilic cystitis and in the present case there was a striking history of injury 1 month before the symptoms of ureteral obstruction.

Adult↗
PubMed1979

Complexity transmission during replication.

The transmission of complexity during DNA replication has been investigated to clarify the significance of this molecular property in a deterministic process. Complexity was equated with the amount of randomness within an ordered molecular structure and measured by the entropy of a posteriori probabilities for discrete (monomer sequences, atomic bonds) and continuous (torsion angle sequences) structural parameters in polynucleotides, proteins, and ligand molecules. A theoretical analysis revealed that sequence complexity decreases during transmission from DNA to protein. It was also found that sequence complexity limits the attainable complexity in the folding of a polypeptide chain and that a protein cannot interact with a ligand moiety of higher complexity. The analysis indicated, furthermore, that in any deterministic molecular process a cause possesses more complexity than its effect. This outcome broadly complies with Curie's symmetry principle. Results from an analysis of an extensive set of experimental data are presented; they corroborate these findings. It is suggested, therefore, that complexity governs the direction of order-order molecular transformations. Two biological implications are (i) replication of DNA in a stepwise, repetitive manner by a polymerase appears to be a necessary consequence of structural constraints imposed by complexity, and (ii) during evolution, increases in complexity had to involve a nondeterministic mechanism. This latter requirement apparently applied also to development of the first replicating system on earth.

Base Sequence↗
PubMed1979

Eosinophilic cystitis. A study of 16 cases.

The authors describe 16 examples of eosinophilic cystitis. Cases were predominately in older men, and usually were associated with other conditions of the bladder or prostate. In contrast, most of the 21 cases reported in the English language were in women and children who had a low incidence of associated bladder conditions, but often had allergic disorders and eosinophilia. It appears that either bladder injury or allergy predisposes to eosinophilic cystitis. The bladder-injury type probably occurs fairly commonly and can be misdiagnosed both clinically and pathologically. In most of the present series, the clinical diagnosis was carcinoma of the bladder, and some biopsy specimens superficially resembled specimens from cases of nonspecific chronic inflammation. There was muscle necrosis in most examples, and significant replacement fibrosis of muscle in all the latter sometimes masquerading as mucosal fibrosis. Giemsa stain for eosinophils and trichrome stain for muscle fibrosis are helpful diagnostic aids. Also, eosinophilic cystitis appears related to allergic cystitis and interstitial cystitis.

Aged↗
PubMed1978

Rate of polymer formation and entropy production during competitive replication.

The rate of increase in the mean polymer formation rate constant during competitive replication by Qbeta RNA variants (Kramer et al., 1974) has been shown to agree statistically with the variance in their formation rate constants. This result demonstrates that Fisher's fundamental theorem of natural selection (Fisher, 1930) can define time variations in the mean rate of synthesis for a heterogeneous population of replicating polymers. It was also revealed that RNA replication, far from equilibrium, accompanied a progressive decrease in the order of the entropy production derivative, with respect to time, that reached a maximum (with the next higher order being zero). Maximization of entropy at equilibrium, in compliance with the second law of thermodynamics, therefore appears as a natural extension of the earlier non-equilibrium pattern of entropy production within the system. The order of the zero-valued entropy production derivative was shown to be determined by the chemical affinity, and its rate of decrease was specified by the mean polymer formation rate constant.

Biological Evolution↗
PubMed1977

Banding and spiralization of human metaphase chromosomes.

A new technique is described which produces spiralization of human metaphase chromosomes. The important feature is heat followed by trypsin treatment. By varying conditions, it is possible to produce bands, spirals and intermediate stages. This provides a new approach to the understanding of banding and chromosome structure.

Chromosomes↗
PubMed1977

The graft-versus-host reactivity in AG-B/MLR disparate strains of rats.

Inbred strains of rats can currently be classified into eight Ag-B groups. Within an Ag-B group, individual strains generally share identity both the Ag-B histocompatibility antigens and mixed lymphocyte responses. In this report we present data from three strains which are Ag-B and mixed lymphocyte reaction (MLR) disparate: KGH (Ag-B7, MLR-1), MNR (Ag-B4, MLR-5), and B3 (Ag-B3, MLR-4). Popliteal lymph node assays involving these three strains and standard inbred strains demonstrate that the graft-versus-host reaction and MLR reactions in the rat are closely related. Positive graft-versus-host reactions were observed only in strain combinations incompatible for the MLR and were unaffected by differences in their Ag-B histocompatibility antigens. The close association of the MLR and graft-versus-host reaction provides additional evidence that the Ag-B/MLR disparity in these strains is the result of natural genetic recombinations within the major histocompatibility complex.

Animals↗