Mid-G1 marker protein(s) in 3T3 mouse fibroblast cells.

Quiescent 3T3 mouse fibroblast cells in a state of growth arrest due to serum deprivation were exposed to [14C]isoleucine. The cell cultures were then stimulated by the addition of 10% fetal calf serum. At various times after stimulation, the 14C-labeled cells were exposed to [3H]isoleucine. Cytoplasmic extracts from the double-labeled cells were subjected to sodium dodecyl sulfate/slab gel electrophoresis. By these procedures it was found that the relative rate of synthesis of a protein species of Mr 50,000 increased after stimulation of quiescent cells, reached a maximum at 5 hr, and then decreased before the 3T3 cells began to enter the S phase. The characteristic peaking profile of mid-G1 protein synthesis exhibited by the Mr 50,000 polypeptide can serve as a useful marker for the progression of events in G1 prior to exit into S.     

Is NSQIP Pediatric review representative of total institutional experience for children undergoing appendectomy?

Background/purpose

NSQIP Pediatric (NSQIP-P) is a robust quality improvement effort. A limitation of the NSQIP process lies in capturing a small proportion of the total case volume. This study examines whether appendectomies captured by NSQIP-P are concordant with all appendectomies, the most commonly captured procedure in 2011.

Methods

We compared case mix and 30-day outcomes between children undergoing an appendectomy who were included in NSQIP (n = 80) and children not captured by NSQIP (n = 276) during 2011 at a tertiary referral children’s hospital. A single surgical case reviewer reviewed all cases using NSQIP-P methodology.

Results

NSQIP-P captured 80 of a total of 356 appendectomies (22%). The case mix was similar between NSQIP and non-NSQIP groups (e.g., 31% of each group had complicated appendicitis). Outcomes were also similar; post-operative occurrences, readmissions and return to the operation room occurred at rates of 7.5% vs. 7.6%, 5% vs. 4.7%, and 3.8% vs. 4.3% respectively.

Conclusion

Although NSQIP-P captured a minority of the total patient population that had an appendectomy, the case mix and outcomes were similar. Our results offer reassurance that NSQIP-P data are representative of the larger population for this procedure. Whether this concordance exists for procedures less commonly performed is unknown and a focus of ongoing work.     

Young neurons from the adult subependymal zone proliferate and migrate along an astrocyte,extracellular matrix-rich pathway

The subependymal zone (SEZ) of the lateral ventricle of adult rodents has long been known to be mitotically active. There has been increased interest in the SEZ, since it has been demonstrated that neuroepithelial stem cells residing there generate neurons in addition to glia in vitro. In the present study, we have examined parasagittal sections of the adult mouse brain using immunocytochemistry for extracellular matrix (ECM) molecules (tenascin and chondroitin sulfate-containing proteoglycans), glial fibrillary acidic protein (GFAP, a cytoskeletal protein prominently expressed by immature and reactive astrocytes), RC-2 (a radial glial and immature astrocyte cytoskeletal marker), TuJ1 (a class III β-tubulin isoform expressed solely by postmitotic and adult neurons), nestin (a cytoskeletal protein associated with stem cells), neuron-specific enolase, and bromodeoxyuridine (BrdU, which is taken up by dividing cells). Our results demonstrate that a population of young neurons reside within an ECM-rich, GFAP-positive astrocyte pathway from the rostral SEZ all the way into the olfactory bulb. Furthermore, BrdU labeling studies indicate that there is a high level of cell division along the entire length of this path, and double-labeling studies indicate that neurons committed to a neuronal lineage (i.e., TuJ1+) take up BrdU (suggesting they are in the DNA synthesis phase of the cell cycle), again along the entire length of the SEZ “migratory pathway.” Thus, the SEZ appears to retain the ability to produce neurons and glia throughout the life of the animal, functioning as a type of “brain marrow.” The implications of these findings are discussed in relation to the role that such a glial/ECM-rich boundary (as seen in the embryonic cortical subplate and other developing areas) may play in: confining the migratory populations and maintaining them in a persistent state of immaturity; facilitating their migration to the olfactory bulb, where they are incorporated into established adult circuitries; and potentially altering SEZ cell cycle dynamics that eventually lead to cell death. © 1996 Wiley-Liss, Inc.     

Participant Engagement and Reactance to a Short,Animated Video About Added Sugars: Web-based Randomized Controlled Trial

BackgroundShort, animated story-based (SAS) videos are a novel and promising strategy for promoting health behaviors. To gain traction as an effective health communication tool, SAS videos must demonstrate their potential to engage a diverse and global audience. In this study, we evaluate engagement with a SAS video about the consumption of added sugars, which is narrated by a child (a nonthreatening character), a mother (a neutral layperson), or a physician (a medical expert).ObjectiveThis study aims to (1) assess whether engagement with the sugar intervention video differs by narrator type (child, mother, physician) and trait proneness to reactance and (2) assess whether the demographic characteristics of the participants (age, gender, education status) are associated with different engagement profiles with the sugar intervention video.MethodsIn December 2020, after 4013 participants from the United Kingdom completed our randomized controlled trial, we offered participants assigned to the placebo arms (n=1591, 39.65%) the choice to watch the sugar intervention video (without additional compensation) as posttrial access to treatment. We measured engagement as the time that participants chose to watch the 3.42-minute video and collected data on age, gender, education status, and trait reactance proneness. Using ordinary least squares regression, we quantified the association of the demographic characteristics and trait reactance proneness with the sugar video view time.ResultsOverall, 66.43% (n=1047) of the 1576 participants in the 2 placebo arms voluntarily watched the sugar intervention video. The mean view time was 116.35 (52.4%) of 222 seconds. Results show that view times did not differ by narrator (child, mother, physician) and that older participants (aged 25-59 years, mean = 125.2 seconds) watched the sugar video longer than younger adults (aged 18-25 years, mean = 83.4 seconds). View time remained consistent across education levels. Participants with low trait reactance (mean = 119.3 seconds) watched the intervention video longer than high-trait-reactance participants (mean = 95.3 seconds), although this association did not differ by narrator type.ConclusionsThe majority of participants in our study voluntarily watched more than half of the sugar intervention video, which is a promising finding. Our results suggest that SAS videos may need to be shorter than 2 minutes to engage people who are young or have high trait proneness to reactance. We also found that the choice of narrator (child, mother, or physician) for our video did not significantly affect participant engagement. Future videos, aimed at reaching diverse audiences, could be customized for different age groups, where appropriate.Trial RegistrationGerman Clinical Trials Register DRKS00022340; https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00022340International Registered Report Identifier (IRRID)RR2-10.2196/25343     

A genetic linkage map for zebrafish: comparative analysis and localization of genes and expressed sequences

Genetic screens in zebrafish (Danio rerio) have isolated mutations in hundreds of genes with essential functions. To facilitate the identification of candidate genes for these mutations, we have genetically mapped 104 genes and expressed sequence tags by scoring single-strand conformational polymorphisms in a panel of haploid siblings. To integrate this map with existing genetic maps, we also scored 275 previously mapped genes, microsatellites, and sequence-tagged sites in the same haploid panel. Systematic phylogenetic analysis defined likely mammalian orthologs of mapped zebrafish genes, and comparison of map positions in zebrafish and mammals identified significant conservation of synteny. This comparative analysis also identified pairs of zebrafish genes that appear to be orthologous to single mammalian genes, suggesting that these genes arose in a genome duplication that occurred in the teleost lineage after the divergence of fish and mammal ancestors. This comparative map analysis will be useful in predicting the locations of zebrafish genes from mammalian gene maps and in understanding the evolution of the vertebrate genome.     

Free amino acids exhibit anthozoan "host factor" activity: they induce the release of photosynthate from symbiotic dinoflagellates in vitro

Reef-building corals and other tropical anthozoans harbor endosymbiotic dinoflagellates. It is now recognized that the dinoflagellates are fundamental to the biology of their hosts, and their carbon and nitrogen metabolisms are linked in important ways. Unlike free living species, growth of symbiotic dinoflagellates is unbalanced and a substantial fraction of the carbon fixed daily by symbiont photosynthesis is released and used by the host for respiration and growth. Release of fixed carbon as low molecular weight compounds by freshly isolated symbiotic dinoflagellates is evoked by a factor (i.e., a chemical agent) present in a homogenate of host tissue. We have identified this "host factor" in the Hawaiian coral Pocillopora damicornis as a set of free amino acids. Synthetic amino acid mixtures, based on the measured free amino acid pools of P. damicornis tissues, not only elicit the selective release of 14C-labeled photosynthetic products from isolated symbiotic dinoflagellates but also enhance total 14CO2 fixation.     

The Role of 1N-Ethenoadenosine Triphosphate and 1N-Ethenoadenosine Monophosphate in Firefly Luminescence

1,N⁶-Ethenoadenosine triphosphate (ε-ATP) has been found to be inactive as a substrate for firefly luciferase. However, chemically synthesized luciferyl-εAMP is oxidized by luciferase and light is emitted. The color of the light is red in contrast to the normal yellow-green observed with luciferyladenylate. Although εATP will not serve as a substrate in the activation reaction, the reversal of the activation, pyrophosphorolysis of dehydroluciferyladenylate, will occur with the ethenoadenosine analog.     

Comprehensive analysis of the acute toxicities induced by systemic administration of cationic lipid:plasmid DNA complexes in mice

A major limitation associated with systemic administration of cationic lipid:plasmid DNA (pDNA) complexes is the vector toxicity at the doses necessary to produce therapeutically relevant levels of transgene expression. Systematic evaluation of these toxicities has revealed that mice injected intravenously with cationic lipid:pDNA complexes develop significant, dose-dependent hematologic and serologic changes typified by profound leukopenia, thrombocytopenia, and elevated levels of serum transaminases indicative of hepatocellular necrosis. Vector administration also induced a potent inflammatory response characterized by complement activation and the induction of the cytokines IFN-gamma, TNF-alpha, IL-6, and IL-12. These toxicities were found to be transient, resolving with different kinetics to pretreatment levels by 14 days posttreatment. The toxic syndrome observed was independent of the cationic lipid:pDNA ratio, the cationic lipid species, and the level of transgene expression attained. Mechanistic studies determined that neither the complement cascade nor TNF-alpha were key mediators in the development of these characteristic toxicities. Administration of equivalent doses of the individual vector components revealed that cationic liposomes or pDNA alone did not generate the toxic responses observed with cationic lipid:pDNA complexes. Only moderate leukopenia was associated with administration of cationic liposomes or pDNA alone, while only mild thrombocytopenia was noted in pDNA-treated animals. These results establish a panel of objective parameters that can be used to quantify the acute toxicities resulting from systemic administration of cationic lipid:pDNA complexes, which in turn provides a means to compare the therapeutic indices of these vectors.     

Hearing in the elderly--the Framingham cohort, 1983-1985: Part II. Prevalence of central auditory processing disorders.

The relation between central auditory processing disorders (CAPD) and age has been described in selected subjects. However, the prevalence of CAPD in the general population has not been established. We tested 1026, 64- to 93-yr-old members of the Framingham Heart Study cohort with Central Institute for the Deaf W-22 lists (CID W-22) in quiet, the Synthetic Sentence Identification test with ipsilateral competing message (SSI-ICM), and the Staggered Spondaic Word test. The presence or absence of CAPD could be established with at least one of three indices in 1018 subjects. The CID W-22 performance-intensity function rollover index was greater than 0.20 in 1.4% of 1009 subjects. The difference between maximum CID W-22 and SSI-ICM (0 dB message-to-competition ratio) scores was greater than 20% in 18.2% of 816 subjects. The Staggered Spondaic Word category was moderately, severely, over-corrected moderately, or over-corrected severely abnormal in 10.7% of 941 subjects (using 12-59-yr-olds' norms and adjusting scores when appropriate). Abnormal results on any one index occurred in 22.6% of the subjects. Thus, we conclude that the prevalence of CAPD in the elderly is less common than previous studies would suggest. Furthermore, although the rate of CAPD increased with age, age accounted for no more than 15% of the variability of any of the three indices. Therefore, its presence is dominated by factors other than chronological age.     

Incidence of hearing decline in the elderly

Pure-tone audiometry was done on 1475 persons on two occasions 6 years apart by the same audiologist in the same facility. The age of the subjects ranged from 58 to 88 years at the initial testing and 63 to 95 at the second. The average 6-year threshold change ranged from 1 to 8 dB at 250-6 kHz and 10-15 dB at 8 kHz. The differences in thresholds fell into two patterns, one for low frequencies (250-1 kHz) and the other for high frequencies (4-8 kHz). For the lows, thresholds worsened at an increasing rate with increasing age independent of the initial hearing level, and women's thresholds worsened more than men's. For the highs, the rate of threshold change decreased with age and with the initial threshold at rates that did not differ between genders. Using a change in PTA (0.5, 1, 2 kHz) of greater than 10 dB as a criterion, significant worsening occurred in the right ear in 8.5%, in the left ear in 13.5%, and in both ears of 4.1% of the subjects over the 6 year period. The rate of significant worsening increased with age. Although hearing loss increased with age, age alone accounted for less than 10% of the variance. Therefore, factors that co-vary with age may be responsible. The difference in phenomena between the low frequencies and the highs suggests that two different processes are occurring. Hair-cell degeneration is the most likely cause for the change in the high frequencies. Strial atrophy or other intracochlear processes may be the cause of the low frequency changes.