Policies, practices, and attitudes of North American medical journal editors

OBJECTIVE: To describe U.S. and Canadian medical journals, their editors, and policies that affect the dissemination of medical information. DESIGN: Mailed survey. PARTICIPANTS: Senior editors of all 269 leading medical journals published at least quarterly in the United States and Canada, of whom 221 (82%) responded. MAIN MEASURES: The questionnaire asked about characteristics of journal editors and their journals and about journals' policies toward peer review, conflicts of interest, prepublication discussions with the press, and pharmaceutical advertisements. RESULTS: The editors were overwhelmingly men (96%), middle-aged (mean age 61 years), and trained as physicians (82%). Although 98% claimed that their journals were "peer-reviewed," the editors differed in how they defined a "peer" and in the number of peers they deemed optimal for review. Sixty-three percent thought journals should check on reviewers' potential conflicts of interest, but only a minority supported masking authors' names and affiliations (46%), checking reviewers' financial conflicts of interest (40%), or revealing reviewers' names to authors (8%). The respondents advocated discussion of scientific findings with the press (84%), but only in accord with the Ingelfinger rule, i.e., after publication of the article (77%). Fifty-seven percent of the editors agreed that journals have a responsibility to ensure the truthfulness of pharmaceutical advertisements, and 40% favored subjecting advertisements to the same rigorous peer review as scientific articles. CONCLUSIONS: The responding editors were relatively homogeneous demographically and professionally, and they tended to support the editorial status quo. There was little sentiment in favor of tampering with the current peer-review system (however defined) or the Ingelfinger rule, but a surprisingly large percentage of the respondents favored more stringent review of drug advertisements.     

Preferences of pregnant women for amniocentesis or chorionic villus sampling for prenatal testing: comparison of patients' choices and those of a decision-analytic model

Decision analytic models have suggested that the choice of amniocentesis or chorionic villus sampling for prenatal genetic testing is a utility-driven decision. We compared preferences for prenatal testing among 156 pregnant women who had chosen either amniocentesis (n = 82) or chorionic villus sampling (n = 74) for the indication of maternal age. We also compared their choices with those of a decision-analytic model based on their preferences, and age-specific rates of spontaneous abortion and chromosomal abnormalities. Preferences were assessed using written scenarios describing potential outcomes of prenatal testing, and were recorded on linear rating scales. The differences in preference ratings for first- vs second-trimester prenatal diagnosis of a normal child (4.2 vs -1.6, p = 0.0004), and for first- vs second-trimester abortion of an abnormal fetus (4.4 vs -1.6, p = 0.01), were significantly greater among women choosing chorionic villus sampling than among women choosing amniocentesis. There were no significant differences between chorionic villus sampling and amniocentesis patients in their preference ratings for test-related miscarriage, disconfirmed results at pregnancy termination, or maternal morbidity from therapeutic abortion. After adjusting for demographic and obstetric factors, the difference in preferences for early vs late prenatal diagnosis was an independent predictor of the choice of chorionic villus sampling in a multivariate model. Among women whose decision analyses selected amniocentesis, 56.8% had chosen amniocentesis, and among women whose analyses selected chorionic villus sampling, 63.2% had chosen chorionic villus sampling (p = 0.05). We conclude that the preferences of pregnant women for the outcomes of prenatal testing were associated with their choice of amniocentesis or chorionic villus sampling. In addition, the choice of prenatal test made by the majority of women was concordant with that of a decision-analytic model that incorporated their preferences. Nevertheless, because many women made choices that were discordant with their decision-analytic results, further research into the bases for their choices is warranted.     

Use of esmolol to prevent hemodynamic changes during intubation in general anesthesia

Regeneration-competent urodele Amphibia are highly resistant to spontaneous development of neoplasms, in comparison with other vertebrates which do not exhibit great regenerative power. This observation implies that at least one growth parameter of urodele cells might be subject to different developmental mechanisms than the cells of animals incapable of epimorphic regeneration. Therefore, keeping records concerning the incidence of tumors in urodeles and investigating those exceptional cases might prove invaluable in understanding the basic biological principles governing organ regeneration and carcinogenesis, and might therefore help in cancer therapy. The present report depicts a case of two spontaneous, dermal, melanoma-like tumors found in an adult newt Triturus cristatus. Both tumors were located in the pelvic region. Histological examinations and tumor transplantations were conducted. It was found that the tumors were melanomata. When allografted within the body cavity, their mass was progressively eliminated.     

Boundary conditions for the diffusion equation in radiative transfer

Using the method of images, we examine the three boundary conditions commonly applied to the surface of a semi-infinite turbid medium. We find that the image-charge configurations of the partial-current and extrapolated-boundary conditions have the same dipole and quadrupole moments and that the two corresponding solutions to the diffusion equation are approximately equal. In the application of diffusion theory to frequency-domain photon-migration (FDPM) data, these two approaches yield values for the scattering and absorption coefficients that are equal to within 3%. Moreover, the two boundary conditions can be combined to yield a remarkably simple, accurate, and computationally fast method for extracting values for optical parameters from FDPM data. FDPM data were taken both at the surface and deep inside tissue phantoms, and the difference in data between the two geometries is striking. If one analyzes the surface data without accounting for the boundary, values deduced for the optical coefficients are in error by 50% or more. As expected, when aluminum foil was placed on the surface of a tissue phantom, phase and modulation data were closer to the results for an infinite-medium geometry. Raising the reflectivity of a tissue surface can, in principle, eliminate the effect of the boundary. However, we find that phase and modulation data are highly sensitive to the reflectivity in the range of 80-100%, and a minimum value of 98% is needed to mimic an infinite-medium geometry reliably. We conclude that noninvasive measurements of optically thick tissue require a rigorous treatment of the tissue boundary, and we suggest a unified partial-current--extrapolated boundary approach.     

The protein tyrosine kinase p56lck regulates cell adhesion mediated by CD4 and major histocompatibility complex class II proteins

The CD4 protein is expressed on a subset of human T lymphocytes that recognize antigen in the context of major histocompatibility complex (MHC) class II molecules. Using Chinese hamster ovary (CHO) cells expressing human CD4, we have previously demonstrated that the CD4 protein can mediate cell adhesion by direct interaction with MHC class II molecules. In T lymphocytes, CD4 can also function as a signaling molecule, presumably through its intracellular association with p56lck, a member of the src family of protein tyrosine kinases. In the present report, we show that p56lck can affect cell adhesion mediated by CD4 and MHC class II molecules. The expression of wild-type p56lck in CHO-CD4 cells augments the binding of MHC class II+ B cells, whereas the expression of a mutant p56lck protein with elevated tyrosine kinase activity results in decreased binding of MHC class II+ B cells. Using site-specific mutants of p56lck, we demonstrate that the both the enzymatic activity of p56lck and its association with CD4 are required for this effect on CD4/MHC class II adhesion. Further, the binding of MHC class II+ B cells induces CD4 at the cell surface to become organized into structures resembling adhesions-type junctions. Both wild-type and mutant forms of p56lck influence CD4-mediated adhesion by regulating the formation of these structures. The wild-type lck protein enhances CD4/MHC class II adhesion by augmenting the formation of CD4-associated adherens junctions whereas the elevated tyrosine kinase activity of the mutant p56lck decreases CD4-mediated cell adhesion by preventing the formation of these structures.     

Oral health assessment of an adult rural community

A pneumatic indentation system using a copper bellows has been developed for physiological studies where a controlled uniaxial compressive force is required to be applied to the surface of the skin. Such a system is useful for studies where the physiological response of the tissues is to be monitored following a known loading history. The indentation system is driven by a vacuum/compression pneumatic pump through solenoid valves under closed-loop computer control. A load cell placed between the indentor and bellows monitors the applied force providing a feedback signal to the computer. The signal from the computer activates the valves supplying air pressure to the bellows, and the applied force is controlled using a digital closed-loop protocol. This system can be used to provide a controlled loading sequence to the skin without utilizing gravitational forces, which allows the subject to keep a more natural position during the experiment.     

Effects of hypothermia or anesthetics on hippocampal glutamate and glycine concentrations after repeated transient global cerebral ischemia

The reovirus group C temperature-sensitive mutant tsC447, whose defect maps to the S2 gene, which encodes the major core protein sigma 2, fails to assemble core particles at the nonpermissive temperature. To identify other proteins that may interact with sigma 2 during assembly, we generated and examined 10 independent revertants of the mutant. To determine which gene(s) carried a compensatory suppressor mutation(s), we generated intertypic reassortants between wild-type reovirus serotype 1 Lang and each revertant and determined the temperature sensitivities of the reassortants by efficiency-of-plating assays. Results of the efficiency-of-plating analyses indicated that reversion of the tsC447 defect was an intragenic process in all revertants. To identify the region(s) of sigma 2 that had reverted, we determined the nucleotide sequences of the S2 genes. In all revertant sequences examined, the G at nucleotide position 1166 in tsC447 had reverted to the A present in the wild-type sequence. This reversion leads to the restoration of a wild-type asparagine (in place of a mutant aspartic acid) at amino acid 383 in the sigma 2 sequence. These results collectively indicate that the functional lesion in tsC447 is Asp-383 and that this lesion cannot be corrected by alterations in other core proteins. These observations suggest that this region of sigma 2, which may be important in mediating assembly of the core particle, does not interact significantly with other reovirus proteins.     

CSF neuroactive steroids in affective disorders: pregnenolone, progesterone, and DBI

Recently several steroid compounds have been discovered to act as neuromodulators in diverse central nervous system (CNS) functions. We wondered if neuroactive steroids might be involved in affective illness or in the mode of action of mood-regulating medications such as carbamazepine. Levels of the neuroactive steroids pregnenolone and progesterone, as well as the neuropeptide diazepam binding inhibitor (DBI) (known to promote steroidogenesis), were analyzed from cerebrospinal fluid (CSF) obtained by lumbar puncture (LP) from 27 medication-free subjects with affective illness and 10 healthy volunteers. Mood-disordered subjects who were clinically depressed at the time of the LP had lower CSF pregnenolone (n = 9, 0.16 ng/ml) compared with euthymic volunteers (n = 10, 0.35 ng/ml; p < 0.01). In addition, pregnenolone was lower in all affectively ill subjects (n = 26, 0.21 ng/ml), regardless of mood state on the LP day, than healthy volunteers (p < 0.05). No differences were found for progesterone or DBI levels by mood state or diagnosis. Progesterone, pregnenolone, and DBI did not change significantly or consistently in affectively ill subjects after treatment with carbamazepine. CSF pregnenolone is decreased in subjects with affective illness, particularly during episodes of active depression. Further research into the role of neuroactive steroids in mood regulation is warranted.     

Loss of parathyroid hormone-stimulated 1,25-dihydroxyvitamin D3 production in aging does not involve protein kinase A or C pathways

Intestinal calcium absorption declines with aging as a result of decreased renal 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] biosynthesis. At least part of the decline in 1,25-(OH)2D3 may be due to acquired resistance to parathyroid hormone (PTH) stimulation of renal 25-hydroxyvitamin D1-hydroxylase (1-OHase) activity. To test whether aging rats can increase 1,25-(OH)2D3 production in response to PTH, male rats of the same litter were fed a normal Ca diet and were sacrificed at 175-225 g (young rats) or 3 months later at 350-425 g (aging rats). At sacrifice, basal serum 1,25-(OH)2D3 levels (88 +/- 16 versus 49 +/- 8 pg/ml, P < 0.05) and in vitro renal proximal tubule 1-OHase activity (178 +/- 15 versus 77 +/- 5 pmol/mg protein/5 minutes, n = 6, P < 0.001) were lower in aging animals. rPTH-(1-34) (10(-11) or 10(-7) M) increased in vitro 1,25-(OH)2D3 secretion by perifused renal proximal tubules from young but not aging rats. For young and aging rats, rPTH-(1-34) (10(-7) M) increased proximal tubule cAMP-dependent protein kinase (PKA) activity, and lower concentrations (10(-11) M) stimulated translocation of protein kinase C (PKC) activity from cytosolic to soluble membrane proximal tubule cell fractions. The results of this study show that PTH activation of 1,25-(OH)2D3 production may involve both signaling pathways, with the PKC pathway responsive to lower concentrations of the hormone. The acquired resistance to PTH stimulation of 1,25-(OH)2D3 production in aging appears not to involve the hormonal activation of PKA or PKC.