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.

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.

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.

Evaluating quality isn't worth the cost.... unless

The uses for valid patient care data are increasing. However, evaluating quality of care must be done in a more efficient, productive manner if the cost is ever to be justified. Five suggestions are provided to develop better study methods for this purpose.

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.

Six flaws revealed: how to make your audit/MCE studies more meaningful

A study that lacks a definite design lacks direction and is defeated before it starts. Careful study design, however, is not the only indication of a successful audit. Approaching variation analysis in a positive rather than punitive manner enhances the committee's ability to recognize important findings and discover imaginative uses for audit data. When problems in care are revealed through evaluation activities, the committee must make recommendations that are appropriate to the causes of the problem and that can be readily implemented. An audit committee that discharges these responsibilities will produce a study that should surely yield informative data. The committee's ultimate goal--improved patient care--can not be far behind.

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.

The use of a fluorescence typing method in an epidemiological study of Klebsiella infection in a London hospital

The fluorescent antibody technique was used to investigate an epidemic of Klebsiella infection in a urological ward and to trace the probable source to a contaminated sink in the treatment room. It was also shown that cross infections by particular capsular types were very common within each ward. Certain types of Klebsiella occurred in cut flower water but could not be associated with the types infecting the patients. Antibiotic resistance patterns within one capsular type were found to vary whether the type was from different sources in one patient or from different patients in the same ward. One capsular type was observed to develop resistance to increasing numbers of antibiotics over a 3-year period. This was probably due to the acquisition of R-plasmids. There also appeared to be a relation between capsular type and the site of infection. The frequency of Klebsiella infections in the urological wards dropped significantly after up-grading the treatment room, improving catheter storage and reducing ampicillin use.

Association of factor XI and high molecular weight kininogen in human plasma

Factor XI and high molecular weight kininogen were found associated in normal human plasma at mol wt 380,000 as assessed by gel filtration on Sephadex G-200. The molecular weight of Factor XI in high molecular weight kininogen-deficient plasma was 175,000, the same value obtained for purified Factor XI. When high molecular weight kininogen-deficient plasma was reconstituted with purified high molecular weight kininogen, all of the Factor XI was then found at mol wt 380,000. Complex formation was also demonstrable upon incubation of Factor XI and highly purified high molecular weight kininogen. This complex was distinct from the prekallikrein-high molecular weight kininogen complex; thus high molecular weight kininogen forms bimolecular complexes with either Factor XI or prekallikrein but does not form a trimolecular complex that includes both Factor XI and prekallikrein. Neither Hageman factor nor plasminogen were found associated with high molecular weight kininogen; binding to high molecular weight kininogen appeared to be a specific property of the Hageman factor substrates.

Isolation and characterization of canine secretory immunoglobulin M

Canine secretory immunoglobulin M, isolated from both colostrum and bronchial secretions, contained the unique glycoprotein bound secretory component. The presence of this extra subunit accounted for the differences in size, quaternary structure, and antigenicity observed upon comparison of secretory immunoglobulin M with its serum counterpart. Approximately 90% of the isolated secretory immunoglobulin M contained covalently bound secretory component while, in the remainder of the population, secretory component was loosely attached and easily dissociated from the immunoglobulin. Following peptide bond cleavage with cyanogen bromide, the release of bound secretory component and J chain from secretory immunoglobulin M was not detected. Because cyanogen bromide cleavage of secretory immunoglobulin A results in the release of these subunits, differences in the primary structure of secretory immunoglobulin M and secretory immunoglobulin A must exist around the binding sites for secretory component and J chain.

Impact of intensive newborn care on neonatal mortality in a community hospital

Development of a Perinatal Center delivering Level 3 intensive care in a community hospital is described. The inborn neonatal mortality at the hospital in which the Center is located, as well as that of the 13 surrounding counties, has diminished more rapidly than the state neonatal mortality. This has coincided with an almost constant delivery rate, increased proportion of staff patients, relatively constant rate of low birth weight, and declining total perinatal mortality. Our experience suggests that appropriately trained and motivated people, not equipment or geographic location, represent the key factor in the development of such a center.

Rat liver cytoplasmic glucose-6-phosphate dehydrogenase. Steady-state kinetic properties and circular dichroism

Steady-state kinetic studies including initial velocity, NADPH product inhibition, dead-end inhibition, and combined dead-end and product inhibition measurements with purified rat liver glucose-6-phosphate dehydrogenase indicate a sequential and obligatory addition of substrates in the order of NADP+, glucose-6-P for the catalytic pathway at pH 8.0. Although instability of 6-phosphoglucono-delta-lactone precluded product inhibition experiments which might directly exclude an enzyme-6-phosphoglucono-delta-lactone complex, the absence of an enzyme-glucose-6-P complex suggests that the enzyme-lactone product is unlikely and the release of products is also ordered, with NADPH released last. Consideration of the kinetic constants (Ka = 2.0 muM, Kiq = 13 muM) and cellular concentration of the substrates and products suggests extensive inhibition of the enzyme in vivo and control by the NADPH/NADP+ ratios. Circular dichroism spectra of the enzyme in 20 mM phosphate buffer at pH 7.0 and 25 degrees C indicate 51% helix and 33% pleated sheet structures which is considerably different from results (14% helix) with yeast enzymes.

Structural composition of canine secretory component and immunoglobulin A

Dog serum and colostral immunoglobulin A (IgA) and free secretory component from colostrum were isolated using affinity chromatography. Both serum and colostral IgA showed similar susceptibility to reduction with dithiothreitol, but only colostral IgA released the additional subunit, bound secretory component. This released secretory component was identical with free secretory component with respect to electrophoretic migration, isoelectric focusing point, and molecular weight, but lacked some antigenic determinants. The amino acid composition and the N-terminal sequence of canine free secretory component was similar to that reported for the cow.

Development of cellular and humoral immunity in the respiratory tract of rabbits to Pseudomonas lipopolysaccharide

Immunization with Pseudomonas lipopolysaccharide induced both cellular and humoral immunity in rabbits, particularly in the respiratory tract after intranasal immunization. Either parenteral (i.m.) or intranasal immunization elicited an IgG antibody response in respiratory secretions, but only intranasal immunization produced secretory IgA antibody. Immunization by both routes stimulated serum IgM and IgG agglutinative antibodies. Because both methods of immunization produced skin test reactivity which had components of both Arthus and tuberculin-like reactions, cellular immunity was more readily assessed by the measurement of migration inhibitory factor (MIF) released from immune lymphocytes in respiratory and spleen cell suspensions after challenge with the lipopolysaccharide antigen. After intranasal vaccination, MIF activity was detected in the respiratory tract by direct assay; in contrast, i.m. immunized rabbits did not produce respiratory MIF. Both modes of immunization resulted in splenic MIF activity. However, lymphocytes were only capable of producing MIF for short periods after primary immunization had ended, apparently losing this function in about 2-3 wk. Therefore, it was concluded that cellular immunity by in vitro assay was transient after primary immunization with this Pseudomonas antigen in contrast to the more persistent humoral immunity. The biological significance of immune lymphocytes as part of the coordinated host defense of the lung needs further evaluation.

Heat transfer in teeth

Experiments were conducted to determine the thermal resistance between food and teeth during mastication processes and the drinking of beverages. It was found that the assumption of negligible resistance between food and teeth overestimates greatly the resulting temperature gradients. Also, heat transfer coefficients (reciprocal thermal resistance) during drinking and mastication are below 7.0 X 10 -2 calorie/cm2 second°C.

Thermal fatigue in teeth

This paper presents the results of experiments conducted with extracted human and bovine teeth. The teeth were subjected to thermal cycling at temperatures between 140 and 90 F. The results offer conclusive evidence that thermal fracture may be induced by the thermal stresses caused by the temperature cycling. Less than 3,000 thermal cycles cause severe cracking or the propagation of cracks previously existing in the teeth, or both.