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Biomedical subjects

R E Thompson

Publications and source records attributed to R E Thompson.

At least 91 records · Page 5Linked to original sources
PubMed1981

Enamel loss due to prophylaxis and multiple bonding/debonding of orthodontic attachments.

An in vitro study using steel reference markers in the enamel of 120 permanent premolars was conducted to determine the amount of enamel lost during prophylaxis and during multiple bonding/debonding procedures. A prophylaxis procedure was carried out on eighty teeth. The procedure was standardized with respect to time, pressure, and revolutions of the prophy handpiece. Both bristle brush and rubber cup were used with four different prophylaxis pastes. The enamel loss with the bristle brush (14.38 micrometers) was significantly (p less than 0.01) greater than the loss with the rubber cup (6.9 micrometers). No significant differences were associated with the use of different pastes. Multiple bonding/debonding procedures were conducted with filled and unfilled resin adhesives. Following the initial bond, twenty of the teeth received prophylaxis and acid etching prior to subsequent bonds while the remaining twenty did not. Total enamel loss was 71.5 micrometers in the group bonded with a filled resin with prophylaxis and acid etching between bonds. This was significantly (p less than 0.01) greater than the amount lost (22.3 micrometers) by the group bonded with the same resin without prophylaxis and acid etching between bonds. Total enamel loss was 45.4 micrometers in the group bonded with an unfilled resin with prophylaxis and acid etching between bonds. This was significantly (p less than 0.01) greater than the amount lost (17.8 micrometers) by the group bonded with the same resin without prophylaxis and acid etching between bonds.

Adolescent↗
PubMed1980

A patient care review model to suit both hospitals and PSROs.

Combining internal review and external monitoring, developing new methods of study, interpreting data in a clinically valid way, and making wide use of findings should end what has been an adversary relationship and an ineffective review system.

Hospitals↗
PubMed1979

Nephrotoxicity of Bence Jones proteins in the rat: importance of protein isoelectric point.

Bence Jones proteins (BJP) were isolated from the urine of 12 patients with multiple myeloma and various degrees of renal dysfunction. Proteins were characterized as to type (six type lambda and five type kappa), isoelectric point (pI), and secondary structure by circular dichroism (CD). Clinical renal function was more impaired with type-lambda proteins and with proteins of pI greater than 5.7. CD studies distinguished kappa from lambda proteins in most cases but did not correlate with nephrotoxicity. Protein dimer preparations were tested for nephrotoxicity in aciduric, hydropenic, female, Sprague Dawley rats by following renal function and morphology over 6 hours after injection i.p. of 300 mg of protein. Twelve rats of urine pH less than 5.5 injected with four BJP of pI less than 5.7 showed a mean rise in SUN of 5.3 mg/dl and in creatinine of 0.06 mg/dl, compared with a mean rise of 28.0 mg/dl (SUN) and 0.75 mg/dl (creatinine) in 21 rats injected with seven BJP of pI greater than 5.7 (P less than 0.01). Seven sodium-bicarbonate-fed rats of urine pH greater than 8 injected with a BJP of pI 6.2 showed mean rise in SUN of 1.8 mg/dl and in creatinine of 0.01 mg/dl, compared with 19.3 mg/dl (SUN) and 0.55 mg/dl (creatinine) in 7 aciduric rats injected with the same BJP (P = 0.009). Morphologic and immunohistologic studies showed distal cast formation in 9 rats with acute deterioration in renal function. It is concluded that BJP of pI greater than urine pH are acutely nephrotoxic in the rat by a mechanism that may involve a charge interaction in the distal nephron.

Animals↗
PubMed1979

Studies of binding of prekallikrein and Factor XI to high molecular weight kininogen and its light chain.

Prekallikrein and Factor XI have been reported to circulate as complexes with the coagulation cofactor high molecular weight (HMW)-kininogen. In this study we have shown that native HMW-kininogen possesses a strong binding site for prekallikrein and Factor XI with association constants of 3.4 x 10(7) M-1 and 4.2 x 10(8) M-1, respectively. The diminished binding of prekallikrein relative to Factor XI may, in part, account for the ability of kallikrein to leave the surface and interact with other molecules of Hageman factor and HMW-kininogen. Prekallikrein and Factor XI appear to compete for binding to HMW-kininogen, suggesting a single (or closely overlapping) binding site(s). The purified light chain derived from kinin-free HMW-kininogen is shown to compete with native MHW-kininogen for binding to Hageman factor substrates and direct binding of the isolated light chain to prekalikrein and Factor XI is demonstrated. This binding of the light chain to prekallikrein and Factor XI appears to be essential to the function of HMW-kininogen as a coagulation cofactor and further digestion of the light chain with excess kallikrein destroys its coagulant activity.

Binding Sites↗
PubMed1979

Some keys to working with physicians.

Successful cooperative efforts among board, administration, and medical staff are a blend of efficient formal organization and informal personal and professional relationships. Efficient formal organization is an important key to physician participation. Medical staff bylaws frequently can be streamlined to good effect, and the efficiency and productivity of medical staff committees often can be improved.

Conflict, Psychological↗
PubMed1978

Characterization of human high molecular weight kininogen. Procoagulant activity associated with the light chain of kinin-free high molecular weight kininogen.

Human high molecular weight (HMW) kininogen has been isolated and was found to be a single chain protein of approximately equal to 120,000 daltons. Upon digestion with plasma kallikrein bradykinin is generated, and SDS gel electrophoresis of the kinin-free protein reveals an apparent loss in size of 15,000 daltons. The kinin-free kininogen retains full activity as a coagulation factor and consists of two chains: a heavy chain of approximately equal to 66,000 daltons disulfide-linked to a light chain of 37,000 daltons. The heavy chain of HMW kininogen shares antigenic determinants with LMW kininogen and possesses no detectable coagulant activity. The isolated light chain is shown to be responsible for the coagulant activity of HMW kininogen and contains a unique antigenic determinant that distinguishes HMW kininogen from low molecular weight kininogen.

Blood Coagulation Factors↗
PubMed1978

Apparent stability constants of H+ and Mg2" complexes of 5-phosphoribosyl alpha-1-pyrophosphate.

Apparent Mg2+ and H+ stability constants of 5-phosphoribosyl alpha-1-pyrophosphate (ligand, L) complexes were determined from pH titration data at 25 degrees C with an average of 0.17 M NaCl or KCl and 0.20 M ionic strength. The logarithms of calculated macroscopic overall stability constants are: 3.2 (MgL3-), 4.8 (Mg2L-), 6.5 (HL4-), 12.4 H2L3-), 9.4 (Mg HL2-), and 11.0 (MgH2L). Comparison of the stepwise Mg2+ stability constants (log k = 3.2 and 1.6) with those of MgADP- and MgAMP or Mg-hexose-1-P suggests that the first and second Mg2+ bind to the 1-PP and 5-P groups of the ligand, respectively. Reasonable assumptions about relative microscopic constants indicate that several of the microscopic isomers do not achieve significant concentrations over a large range of conditions. Judging from other data on organophosphate complexes, it is likely that the constants of this study may be extrapolated with little error to other conditions of ionic strength 0.1--0.2 M) and temperature (e.g., 15--35 degrees C), and widely different monovalent ion concentrations.

Chemical Phenomena↗