Search

BackgroundPrevious studies have demonstrated low first-time donor return rates (DRR) following catastrophic events. Little is known, however, about the influence of demographic factors on the DRR of first-time donors during the COVID-19 pandemic, including the unique motivation of COVID-19 convalescent plasma (CCP) donors as compared to non-CCP donors.Study design and methodsThirteen blood collection organizations submitted deidentified data from first-time CCP and non-CCP donors returning for regular (non-CCP) donations during the pandemic. DRR was calculated as frequencies. Demographic factors associated with returning donors: race/ethnicity, gender, and generation (Gen Z: 19-24, Millennial: 25-40, Gen X: 41-56, and Boomer: ≥57 years old), within the CCP and non-CCP first-time cohorts were compared using chi-square test at p

As SARS-CoV-2 variants emerge, there is a critical need to understand the effectiveness of serum elicited by different SARS-CoV-2 vaccines. A reference reagent comprised of post-vaccination sera from recipients of different vaccines allows evaluation of in vitro variant neutralization, and provides a reference for comparing assay results across laboratories. We prepared and pooled >1 L serum from donors who received the SARS-CoV-2 mRNA vaccines (BNT162b2, Pfizer and mRNA-1273, Moderna), a replication-incompetent adenovirus type 26 vaccine (Ad26.COV2.S, Johnson and Johnson), or recombinant spike protein expressed by baculovirus incorporated into a nanoparticle vaccine plus Matrix-M adjuvant (NVX-CoV2373, Novavax). Twice frozen sera were aliquoted and are available for distribution to the research community (BEI Resources). The calculated WHO titer of pooled sera to spike protein was 1,312, 1,447, 1,936, and 587 and the reciprocal RBD binding to ACE-2 IC90-titers were 60, 64, 118, and 46 for BNT162b2, mRNA1273, Ad26.CoV2373, and NVX-CoV2373 sera, respectively.

Severe flooding occurred in the midwestern United States in 2001. Since November 2000, coincidentally, data on gastrointestinal symptoms had been collected for a drinking water intervention study in a community along the Mississippi River that was affected by the flood. After the flood had subsided, the authors asked these subjects (n = 1,110) about their contact with floodwater. The objectives of this investigation were to determine whether rates of gastrointestinal illness were elevated during the flood and whether contact with floodwater was associated with increased risk of gastrointestinal illness. An increase in the incidence of gastrointestinal symptoms during the flood was observed (incidence rate ratio = 1.29, 95% confidence interval: 1.06, 1.58), and this effect was pronounced among persons with potential sensitivity to infectious gastrointestinal illness. Tap water consumption was not related to gastrointestinal symptoms before, during, or after the flood. An association between gastrointestinal symptoms and contact with floodwater was also observed, and this effect was pronounced in children. This appears to be the first report of an increase in endemic gastrointestinal symptoms in a longitudinal cohort prospectively observed during a flood. These findings suggest that severe climatic events can result in an increase in the endemic incidence of gastrointestinal symptoms in the United States.

Objective.Groin wound infection (GWI) after femoral artery catheterization is unusual. However, several reports of GWI associated with the use of a Perclose device appear in the surgical literature.Design.A case-control study.Setting.We pooled 23 cases and 83 controls from a university hospital and a community medical center.Patients.A case was defined as a patient who developed a GWI after a femoral artery catheterization. At the university hospital, 3 controls were randomly selected from the at-risk population and matched to each case by time of procedure only (within 2 weeks). At the community medical center, 4 controls were selected and matched to each case by time of procedure (within 2 weeks), sex, and age (within 5 years).Results.We considered several covariates, including age, sex, body mass index, medical conditions, Perclose use, hematoma formation, and antithrombotic therapy. In a multivariate model, only hematoma formation (odds ratio, 68.8; 95% confidence interval, 12.1-391.4) and glycoprotein IIb/IIIa platelet inhibitor therapy (odds ratio, 6.1; 95% confidence interval, 1.1-33.6) were statistically significant predictors of GWI; Perclose use (odds ratio, 0.9; 95% confidence interval, 0.2-3.7) was not a statistically significant predictor of GWI. However, most of the hematomas (15/17) formed after procedures during which a Perclose device was used.Conclusion.Perclose use did not have any additional effect on GWI risk beyond the effect that hematoma formation had.

The interactions of purines and pyrimidines in solution have been studied by measuring their proton magnetic resonance spectra. In dimethyl sulfoxide, a solvent with no exchangeable protons, a hydrogen-bonding interaction between the complementary bases guanine and cytosine is evident in the large down-field shifts of the donor protons. No association is seen for adenine—uracil combinations in this solvent, apparently because of the competition of the capability of hydrogen-bond acceptance of the solvent with that of the bases. In the relatively non-hydrogen bonding solvent chloroform, intermolecular base association between soluble adenine and uracil derivatives is clearly observed. Chemical shifts of the donor protons as a function of varying relative nucleoside concentrations indicates a one-to-one association between guanosine and cytidine. The behavior of the adenine—uracil mixtures indicates a higher-order interaction. By using a mixed solvent system consisting of one hydrogen bond-accepting component and another component which is inert, it is possible to obtain solutions of and to measure the interactions between various nucleosides. In this mixed solvent system a striking specificity of interaction is evident. Guanosine interacts with cytidine strongly and, except for a weak self-association, interacts with no other nucleoside. Uridine associates with adenosine and shows no other interaction. In pure dimethyl sulfoxide, the only interaction of cytidine is with guanosine.

A UHF satellite installation is described. Average field strength improvements of nearly 23 db were obtained in a deep shadow area at Waterbury, Connecticut. 80 db of straight RF amplification was used in conjunction with high gain receiving and transmitting antennas on a frequency of 700 Mc/s.

A digital computer has been programmed to evaluate the interference existing at each receiver in a large-scale army deployment involving about 20,000 receivers and transmitters. In order to reduce data handling problems, spurious responses are considered to be due to separate receivers and transmitters. Propagation path losses are statistically tailored to the terrain. The model is suitable for a parametric analysis of path loss, selectivity, spurious emissions, sensitivity, etc.

The use of color coding accentuates amplitude variations in the "gray scale" of B-scan ultrasonography. Color coding by means of selected "sliced" amplitudes uses red for high amplitude echoes, green for moderate amplitude echoes, and blue for low amplitude echoes in order to accentuate spatial relationships of echoes within tumors, foreign bodies within hemorrhage or tissue, and membrane or retina within vitreous hemorrhage. Color coding systems allow for easier detection of variations in echo amplitudes and the display of these echoes over a larger portion of their dynamic range, features that are essential for ultrasonic diagnosis of tissue abnormalities.

To the Editor. —In the October 1981 issue of theArchives(99:1819-1823), Kenneth Hoffer, MD, published a report dealing with the accuracy of intraocular lens (IOL) calculation using ultrasound for axial length determination. In this report, Hoffer purported to have conducted a survey of the literature and to have performed his own studies on this subject with various ultrasonic instruments and IOL power calculation formulas. He categorically stated that "results of previous studies show that the use of another ultrasound unit (Sonometries DBR) and Binkhorst's formula is the least clinically accurate method." He further stated that he "does not recommend the use of the DBR unit and Binkhorst formula." The fact that Hoffer did not recommend the DBR or the use of the Binkhorst formula is not new. Those who are familiar with Hoffer's past differences with Sonometrics and Dr Binkhorst will recognize an old bias inherent in these

A double-stranded RNA intermediate has been implicated in the replication of viruses containing a single-stranded RNA genome for animal ( Montagnier and Sanders, 1963 , Baltimore et al., 1964 ), bacterial ( Weissman et al., 1964 , Kelly and Sinsheimer, 1964 , Nonoyama and Ikeda, 1964 ) and plant ( Shipp and Haselkorn, 1964 ) viruses. In most systems, the duplex nature of this species of RNA has been demonstrated indirectly by its resistance to enzymatic cleavage by RNAase, although hyperchromism ( Ammann, Delius and Hofschneider, 1964 ) and X-ray diffraction ( Langridge, Billeter, Borst, Burdon and Weissman, 1964 ) have been utilized when very large quantities were available. Because of the very high melting temperature (90–105°C) exhibited by these structures, some degradation invariably accompanies melting, making it difficult to assess the physical integrity of the virus-like strand and of its compliment. We present here a method for achieving strand separation under mild conditions which does not degrade the single strands thus released, and permits one to examine the duplex structure for single-strand breaks. Using this method, we show that the replicative form of poliovirus RNA, which sediments as a single species at 20S can be completely transformed into a more rapidly sedimenting species, whose behavior is the same as single-stranded RNA extracted from mature virus, sedimenting at 35S.

The hydrogen-bonded associations of adenine and uracil derivatives in chloroform solutions have been investigated using high-resolution proton magnetic resonance. The adenine-uracil chemical-shift mixing curves for various derivatives confirm that the equilibrium constants for the hydrogen-bonding interaction are directly reflected in the magnitudes of the observed association shifts. Halogenated uracil derivatives interact more strongly with adenine than does uracil. When the nucleoside solutions are concentrated, the data for the association of adenine and uracil is consistent with the formation of 1:2 triplets. Adenine derivatives which can only form pairs with uracil due to steric hinderance or to reduction of the number of hydrogen-bonding groups, have about half the equilibrium constant of association found for adenine itself. A deshielding effect on ring protons of base-pair formation is reported. Hydrogen-bond formation results in down-field shifts of the protons in the planes of the rings. These shifts are greatest for the C(8)-purine protons and are very small for pyrimidine protons.

9-Ethyladenine and 1-methyl-5-bromouracil crystallize together in a 1:1 complex. The molecular structure of this complex was solved by analysis of 3-dimensional X-ray diffraction data. The two molecules form a nearly planar hydrogen-bonded pair, connected by two hydrogen bonds, N-H…N from the uracil N3 to the adenine imidazole N7 and N-H…O from the adenine amino group nitrogen N6 to the uracil O2. The hydrogen-bonded pairs are connected to pairs in neighboring unit cells through additional hydrogen bonds. The crystal structure has an unusual disordering feature. Approximately 6% of the uracil derivatives have an alternative hydrogen bonding to the adenine residue involving the carbonyl oxygen O4 instead of O2. The effect of the bromine atom on the hydrogen-bonding interaction as well as its possible mode of action in mutagenesis are discussed.