Appropriateness of imaging procedure requests: do radiologists agree?

OBJECTIVE: We explored the agreement among radiologists in their evaluation of the appropriateness of individual requests for imaging procedures. MATERIALS AND METHODS: We reviewed 318 noninterventional CT, sonographic, MR imaging, and nuclear medicine procedures ordered at a general internal medicine clinic during 8 months in 1995. Five subspecialty radiologists used data from the radiology request from and clinic notes to independently rate the appropriateness of each requested imaging procedure on a four-point scale. The radiologists were unaware of the results achieved by each procedure. Each case was reviewed by at least three radiologists, of whom at least one had relevant subspecialty expertise. Agreement among radiologists was analyzed using Cohen's kappa statistic and weighted kappa statistics and Cronbach's alpha statistic. RESULTS: Nonchance agreement (kappa) was .19 +/- .05; weighted kappa was .24 +/- .05. Interrater agreement was significantly greater than that expected from chance alone (p < .01). The composite score, defined as the average of the radiologists' scores for each case, showed moderate reliability, as evidenced by a value for Cronbach's alpha of 70. CONCLUSION: In the absence of explicit criteria, we found modest but statistically significant agreement among radiologists about the appropriateness of individual requests for imaging procedures. The disagreement among radiologists highlights the importance of developing well-reasoned, explicit criteria by which to judge the appropriateness of diagnostic radiology procedures. Further study is needed to elucidate the relationship between appropriateness and actual patient outcomes.

The influence of black race and socioeconomic status on the use of breast-conserving surgery for Medicare beneficiaries.

BACKGROUND: This study explores the influence of socioeconomic status (SES) and black race on the use of breast-conserving surgery (BCS) as opposed to mastectomy for early stage breast carcinoma. METHODS: A cohort of 41,937 female Medicare inpatients age 65-79 years who had undergone BCS or mastectomy treatment in 1990 for local or regional breast carcinoma was studied. SES was estimated based on the patients' zip code of residence. RESULTS: Greater use of BCS was associated with higher income and increased education as determined by the patients' zip code area (P < 0.001 for each), and with lower vacant housing rates and fewer persons living below the poverty line in the patients' zip code area (P < 0.001 for each). Black women were less likely than women of other races to undergo BCS (odds ratio, 0.80; 95% confidence interval, 0.71-0.91). However, in a multivariate regression model adjusting for stage and urban versus rural residence, income, educational status, and poverty rate remained significant predictors of patient receipt of BCS, whereas black race did not remain an independent predictor of this treatment. CONCLUSIONS: Women residing in higher SES areas are more likely to undergo BCS. The reduced use of BCS in black women appears attributable to SES.

Contribution of vitamin K1 to the electron spin polarization in spinach photosystem I.

The electron spin polarized (ESP) electron paramagnetic resonance (EPR) signal observed in spinach photosystem I (PSI) particles was examined in preparations depleted of vitamin K1 by solvent extraction and following biological reconstitution by the quinone. The ESP EPR signal was not detected in the solvent-extracted PSI sample but was restored upon reconstitution with either protonated or deuterated vitamin K1 under conditions that also restored electron transfer to the terminal PSI acceptors. Reconstitution using deuterated vitamin K1 resulted in a line narrowing of the ESP EPR signal, supporting the conclusion that the ESP EPR signals in the reconstituted samples arise from a radical pair consisting of the oxidized PSI primary donor, P700+, and reduced vitamin K1.

Probing the bacteriochlorophyll binding site by reconstitution of the light-harvesting complex of Rhodospirillum rubrum with bacteriochlorophyll a analogues.

Structural features of bacteriochlorophyll (BChl) a that are required for binding to the light-harvesting proteins of Rhodospirillum rubrum were determined by testing for reconstitution of the B873 or B820 (structural subunit of B873) light-harvesting complexes with BChl a analogues. The results indicate that the binding site is very specific; of the analogues tested, only derivatives of BChl a with ethyl, phytyl, and geranylgeranyl esterifying alcohols and BChl b (phytyl) successfully reconstituted to form B820- and B873-type complexes. BChl analogues lacking magnesium, the C-3 acetyl group, or the C-13(2) carbomethoxy group did not reconstitute to form B820 or B873. Also unreactive were 13(2)-hydroxyBChl a and 3-acetylchlorophyll a. Competition experiments showed that several of these nonreconstituting analogues significantly slowed BChl a binding to form B820 and blocked BChl a-B873 formation, indicating that the analogues may competitively bind to the protein even though they do not form red-shifted complexes. With the R. rubrum polypeptides, BChl b formed complexes that were further red-shifted than those of BChl a; however, the energies of the red shifts, binding behavior, and circular dichroism (CD) spectra were similar. B873 complexes reconstituted with the geranylgeranyl BChl a derivative, which contains the native esterifying alcohol for R. rubrum, showed in-vivo-like CD features, but the phytyl and ethyl B873 complexes showed inverted CD features in the near infrared. The B820 complex with the ethyl derivative was about 30-fold less stable than the two longer esterifying alcohol derivatives, but all formed stable B873 complexes.

[Anthropometric examinations of the sick with congenital inborn facial-maxillary-occlusal defects]. / Badania antropometryczne chorych z wrodzonymi wadami twarzowo-szczekowo-zgryzowymi.

The authors describe rules, usefulness and advantages from carrying out anthropometric examinations in the sick with facial-maxillary-occlusal defects in the paper. They present a card especially elaborated for these examinations and used in case of each sick.

Electron spin resonance of charge carriers in chlorophyll a/water micelles.

Chlorophyll a/water micelles (P740) prepared in hydrocarbon media have been shown by small-angle neutron scattering to consist of hollow cylinders whose surface is formed of a monolayer of chlorophyll crosslinked by water. The micelles can be reversibly oxidized or reduced to generate highly mobile holes or electrons that undergo rapid, one-dimensional transport along the chains of chlorophyll macrocycles comprising the surface of the micelles. Large pi-pi overlap within the chains facilitates the one-dimensional charge transport and is expected to do the same for energy transport. Structural defects in the micelle surface act as boundaries for charge transport, confining the spins to one-dimensional domains of approximately 200 macrocycles. The one-dimensional transport within the limited domains results in motionally narrowed electron spin resonance lines with some residual inhomogeneous broadening. Although the chlorophyll a incorporated in micelles is more easily oxidized than is monomeric chlorophyll a, it is much more resistant to chemical alteration.

Bacteriopheophytin g: Properties and some speculations on a possible primary role for bacteriochlorophylls b and g in the biosynthesis of chlorophylls.

Bacteriopheophytin g and small amounts of bacteriochlorophyll g have been obtained in high purity from the recently discovered photosynthetic bacterium Heliobacterium chlorum. Preparative methods and precautions in handling these sensitive compounds are described. The compounds have been characterized by californium-252 plasma desorption mass spectrometry, HPLC, visible absorption, and electron spin resonance spectroscopy. Our results agree with the structure of bacteriochlorophyll g advanced by H. Brockmann and A. Lipinski [(1983) Arch. Microbiol. 136, 17-19], with the exception that we find the esterifying alcohol to be farnesol and not geranylgeraniol as originally suggested. Zero field splitting parameters of triplet state bacteriopheophytin g and the ESR properties of the cation free radical of bacteriochlorophyll g are reported. The photoisomerization of the subject compounds has been studied. Bacteriopheophytin g undergoes photo-isomerization in white light to pheophytin a with a half-time of approximately 42 min. We suggest that all of the chlorophylls are biosynthesized from a common intermediate containing an ethylidine group, [unk]CH-CH(3), such as is present in bacteriochlorophylls b and g.

Small-angle neutron scattering studies of chlorophyll micelles: Models for bacterial antenna chlorophyll.

Micelles of hydrated chlorophyll a (P740), bacteriochlorophyll a (P865), bacteriochlorophyll c (P750), and pheophytin a prepared in organic media have been studied by small-angle neutron scattering to determine their shape, size, and mass per unit length. All of the micelles are hollow cylinders of well-defined size. The P740 and P750 cylinders are essentially monolayers of macrocycles crosslinked by water, probably in an arrangement similar to that of crystals of chlorophyll derivatives. The P865 micelle is more nearly a bilayer of macrocycles. We show that the curvature necessary to form cylinders probably results from intrinsic curvature of the five-coordinated chlorophyll macrocycle. Studies of P740 micelle formation and the disaggregating effects of another nucleophile (pyridine) are described. As the P750 micelles are nearly identical in size and optical spectra to the rod-shaped structures observed in chlorosomes, and the P865 micelles have optical properties very similar to the in vivo properties of the long-wavelength antenna of purple photosynthetic bacteria, we propose that features of the hydrated cylindrical micelles of these chlorophylls provide good models for antenna chlorophyll in photosynthetic bacteria.