Menstrual cycle stage and oral contraceptive effects on anterior tibial displacement in collegiate female athletes.

AIM: The aim of this study was to establish if differences in anterior tibial displacement exists in collegiate female student-athletes at different stages of the menstrual cycle. DESIGN AND SETTING: a 2 x 3 factorial design with repeated measures on the second factor guided this study. The first independent variable was group with 2 levels (control and oral contraceptive) and the second independent variable was menstrual cycle phase with 3 levels (follicular, ovulation, luteal). The single dependent variable was anterior tibial displacement. All data were collected in a research laboratory. SUBJECTS: 53 female student athletes (control: n=28; oral contraceptive: n=25) with no previous history of knee injury or anomalies with a normal 28-30 day menstrual cycle participated. MEASUREMENTS: anterior tibial displacement (mm) measurements were taken on days 1 (follicular phase), 13 (ovulation phase), and 23 (luteal phase) of each subject's menstrual cycle using a KT1000 knee arthrometer. RESULTS: For the entire group, statistically significant increases in anterior tibial laxity were found (F=4.49; df=52.1; P<0.05) between the follicular cycle (0+/-SD =5.14 mm) and ovulation cycle (0+/-SD=5.81 mm); and follicular cycle (0+/-SD=5.14 mm) and luteal cycle (0+/-SD=5.79 mm). A separate analysis of the non-birth control group revealed no significant difference in anterior tibial laxity throughout the stages of the menstrual cycle. CONCLUSION: The results of this study suggest that: 1) the menstrual cycle does have an influence on laxity of the anterior displacement of the knee; 2) significant increases in anterior displacement are shown during the ovulation and luteal phases of the menstrual cycle; and 3) birth control subjects tend to have increased laxity when compared to those subjects who are not on hormone therapy.

Gender differences in the pre-competition temporal patterning of anxiety and hormonal responses.

AIM: This study examined gender differences in the pre-competition temporal patterning of anxiety and hormonal responses. METHODS: Six male and 6 female field hockey players completed the modified Competitive State Anxiety Inventory-2, including both intensity and direction subscales, and provided saliva and urine samples 24, 2, and 1 hour prior to competition. These samples were analyzed for cortisol, and noradrenaline and adrenaline, respectively. RESULTS: Two x 3 repeated measures ANOVAs revealed significant gender x time interactions for cognitive and somatic anxiety intensity and adrenaline and noradrenaline, but not cortisol. While males' anxiety and hormonal responses demonstrated no significant changes, significant increases in females' anxiety, and significant decreases in their adrenaline and noradrenaline were observed over time. Moreover, while males' anxiety and hormonal responses mirrored each other, this was not the case for the females with increases in females' cognitive and somatic anxiety intensity levels accompanied by decreases in adrenaline and noradrenaline. CONCLUSIONS: Although this study has extended this line of research by adopting a psycho-physiological approach and measuring anxiety intensity and direction in male and female athletes, replication is required with larger samples from a greater diversity of sports.

P3b reflects maltreated children's reactions to facial displays of emotion.

Processing of emotion information by maltreated and control children was assessed with event-related brain potentials (ERPs). Maltreated children, for whom negative facial displays may be especially salient, and demographically comparable peers were tested to increase knowledge of differential processing of emotion information. ERPs were measured while children responded to pictures depicting facial displays of anger, fear, and happiness. Maltreated children showed larger P3b amplitude when angry faces appeared as targets than did control children; the two groups did not differ when targets were either happy or fearful facial expressions or for nontargets of any emotional content. These results indicate that aberrant emotional experiences associated with maltreatment may alter the allocation of attention and sensitivity that children develop to process specific emotion information.

The Caenorhabditis elegans peb-1 gene encodes a novel DNA-binding protein involved in morphogenesis of the pharynx, vulva, and hindgut.

Gene expression in the Caenorhabditis elegans pharynx is regulated in part by organ-specific signals, which in the myo-2 gene target a regulatory sequence called the C sub-element. C sub-element activity requires the organ specification factor PHA-4, a winged-helix transcription factor expressed in all pharyngeal cells. To identify additional factors involved in pharyngeal organogenesis, we performed a yeast one-hybrid screen for C sub-element binding proteins. Here we describe the novel factor PEB-1, which is coexpressed with PHA-4 in many pharyngeal cell types, including muscles, epithelial cells, marginal cells, and glands, but is undetectable in the pharyngeal nervous system. PEB-1 is also detected outside the pharynx in cells surrounding the rectum and vulva, as well as in the germ line. Reduction of peb-1 function using RNAi results in morphological defects in the somatic tissues in which peb-1 is expressed. We have mapped the PEB-1 DNA-binding domain to a 158-residue region, which is unrelated to known DNA-binding proteins but shares some sequence similarity to the Drosophila Mod(mdg4) proteins. PEB-1 specifically recognizes a site in the C subelement that partially overlaps the PHA-4 binding site. Both the PEB-1 and the PHA-4 binding sites are necessary for strong C sub-element enhancer activity in some cells in which these factors are coexpressed. In contrast the PEB-1 site is dispensable for C sub-element activity in pharyngeal neurons. We propose that PEB-1 functions with PHA-4 to activate target gene expression in cells in which they are coexpressed.

The influence of Lys68 in decepeptide agonists of C5a on C5a receptor binding, activation and selectivity.

The potent, conformationally biased C5a agonist peptide YSFKPMPLaR (C5a65-74, Y65, F67, P69, P71, D-Ala73) was used as a template to gain insight into the nature and importance of lysine at position 68 in the peptide-receptor interaction. A panel of YSFKPMPLaR analogs with systematic substitutions for Lys68 was evaluated for C5a receptor (C5aR) binding affinity and activation in two well-characterized assay systems: human polymorphonuclear leukocytes (PMNs) and human fetal artery. In addition, we determined the activity of these new analogs in transfected rat basophilic leukemia (RBL) cells in which the Glu at position 199 of the C5aR (wtGlu199) was replaced by a Gln (C5aR-Gln199) or a Lys (C5aR-Lys199). Our results indicated that Lys68 in YSFKPMPLaR plays an important role in binding the C5aR expressed on PMNs and RBL cells. Furthermore, the data indicated that Lys68 interacted with Glu199 of the C5aR in PMNs and RBL cells. In human fetal artery, however, Lys68 substitutions had little or no effect on activity, which suggested that the receptor conformation may be different in this tissue. Thus, the interaction between Lys68 of the decapeptide agonist and Glu199 of the C5aR may be cell type-specific and may form the molecular basis for tissue-specific responses to C5a agonists.

The DAF-3 Smad binds DNA and represses gene expression in the Caenorhabditis elegans pharynx.

Gene expression in the pharyngeal muscles of Caenorhabditis elegans is controlled in part by organ-specific signals, which in the myo-2 gene target a short DNA sequence termed the C subelement. To identify genes contributing to these signals, we performed a yeast one-hybrid screen for cDNAs encoding factors that bind the C subelement. One clone recovered was from daf-3, which encodes a Smad most closely related to vertebrate Smad4. We demonstrated that DAF-3 binds C subelement DNA directly and specifically using gel mobility shift and DNase1 protection assays. Mutation of any base in the sequence GTCTG interfered with binding in the gel mobility shift assay, demonstrating that this pentanucleotide is a core recognition sequence for DAF-3 binding. daf-3 is known to promote formation of dauer larvae and this activity is negatively regulated by TGFbeta-like signaling. To determine how daf-3 affects C subelement enhancer activity in vivo, we examined expression a gfp reporter controlled by a concatenated C subelement oligonucleotide in daf-3 mutants and other mutants affecting the TGFbeta-like signaling pathway controlling dauer formation. Our results demonstrate that wild-type daf-3 can repress C subelement enhancer activity during larval development and, like its dauer-promoting activity, daf-3's repressor activity is negatively regulated by TGFbeta-like signaling. We have examined expression of this gfp reporter in dauer larvae and have observed no daf-3-dependent repression of C activity. These results suggest daf-3 directly regulates pharyngeal gene expression during non-dauer development.

The dynamin-related GTPase, Dnm1p, controls mitochondrial morphology in yeast.

The Saccharomyces cerevisiae Dnm1 protein is structurally related to dynamin, a GTPase required for membrane scission during endocytosis. Here we show that Dnm1p is essential for the maintenance of mitochondrial morphology. Disruption of the DNM1 gene causes the wild-type network of tubular mitochondrial membranes to collapse to one side of the cell but does not affect the morphology or distribution of other cytoplasmic organelles. Dnm1 proteins containing point mutations in the predicted GTP-binding domain or completely lacking the GTP-binding domain fail to rescue mitochondrial morphology defects in a dnm1 mutant and induce dominant mitochondrial morphology defects in wild-type cells. Indirect immunofluorescence reveals that Dnm1p is distributed in punctate structures at the cell cortex that colocalize with the mitochondrial compartment. These Dnm1p-containing structures remain associated with the spherical mitochondria found in an mdm10 mutant strain. In addition, a portion of Dnm1p cofractionates with mitochondrial membranes during differential sedimentation and sucrose gradient fractionation of wild-type cells. Our results demonstrate that Dnm1p is required for the cortical distribution of the mitochondrial network in yeast, a novel function for a dynamin-related protein.

Mitochondrial fusion in yeast requires the transmembrane GTPase Fzo1p.

Membrane fusion is required to establish the morphology and cellular distribution of the mitochondrial compartment. In Drosophila, mutations in the fuzzy onions (fzo) GTPase block a developmentally regulated mitochondrial fusion event during spermatogenesis. Here we report that the yeast orthologue of fuzzy onions, Fzo1p, plays a direct and conserved role in mitochondrial fusion. A conditional fzo1 mutation causes the mitochondrial reticulum to fragment and blocks mitochondrial fusion during yeast mating. Fzo1p is a mitochondrial integral membrane protein with its GTPase domain exposed to the cytoplasm. Point mutations that alter conserved residues in the GTPase domain do not affect Fzo1p localization but disrupt mitochondrial fusion. Suborganellar fractionation suggests that Fzo1p spans the outer and is tightly associated with the inner mitochondrial membrane. This topology may be required to coordinate the behavior of the two mitochondrial membranes during the fusion reaction. We propose that the fuzzy onions family of transmembrane GTPases act as molecular switches to regulate a key step in mitochondrial membrane docking and/or fusion.

Marginal fitness contributions of nonessential genes in yeast.

Analysis of the complete genome sequence of Saccharomyces cerevisiae confirms and extends earlier evidence that a majority of yeast genes are not essential, at least under laboratory conditions. Many fail to yield a discernible mutant phenotype even when disrupted. Genes not subject to natural selection would accumulate inactivating mutations, so these "cryptic" genes must have functions that are overlooked by the standard methods of yeast genetics. Two explanations seem possible: (i) They have important functions only in environments not yet duplicated in the laboratory and would have conditional phenotypes if tested appropriately. (ii) They make small, but significant, contributions to fitness even under routine growth conditions, but the effects are not large enough to be detected by conventional methods. We have tested the second "marginal benefit" hypothesis by measuring the fitnesses of a random collection of disruption mutants in direct competition with their wild-type progenitor. A substantial majority of mutant strains that lack obvious defects nevertheless are at a significant selective disadvantage just growing on rich medium under normal conditions. This result has important implications for efforts to understand the functions of novel genes revealed by sequencing projects.

Induction of glyoxylate cycle expression in Caenorhabditis elegans: a fasting response throughout larval development.

The mRNA and the bifunctional protein for the two glyoxylate cycle (GC) enzymes, isocitrate lyase and malate synthase, are expressed in a tissue- and stage-specific pattern in Caenorhabditis elegans. Since expression of the two enzymes for the carbon-conserving glyoxylate cycle is regulated by the availability of carbon sources in microorganisms, we have studied the bifunctional GCP gene expression under fasting conditions and in certain mutants of C. elegans in order to understand possible mechanisms regulating its expression during nematode development. The GCP mRNA and protein levels were elevated in early larvae which were never fed, a result consistent with previous enzyme activity measurements (Khan, F.R., & McFadden, B.A. (1982) Exp. Parasitol. 54, 48-54]. However, larvae of later stages also expressed higher levels of GCP mRNA and protein when they were shifted from normal to fasting growing conditions. The GCP expression appeared to be regulated primarily at the transcriptional level throughout development. Although the expression of both the GCP gene and lin-14 peaks at about the same time during development and are induced by fasting, the regulation of the GCP gene is independent of the heterochronic lin-14 control mechanism of postembryonic lineages, as demonstrated by the fact that there was no significant change of the GCP at both mRNA and protein levels in the heterochronic lin-4 (lf) and lin-14 (gf) mutants compared to the wild type.

Morphogenesis of denticles and hairs in Drosophila embryos: involvement of actin-associated proteins that also affect adult structures.

We sought components that function in morphogenetic events downstream from the segmentation pathway in Drosophila embryos, so we examined mutations that affect development of adult hairs and/or bristles to identify a subset that also affect hairs and denticles on the cuticle of first instar larvae. Mutations at 4 of 23 loci surveyed cause distinct abnormalities in these larval structures, and two other loci have more subtle, variable effects. In particular, forked and singed mutants produce complex, allele-specific phenotypes. These loci encode actin-associated proteins and, consistent with that information, mutations cause abnormalities in actin bundles that support nascent hairs and denticles in stage 14-16 embryos. We suggest that interactions between these and other actin-associated proteins are important in generating the diverse shapes of the cuticular specializations seen in both larvae and adults.

Follow-up after day surgery: how well do patients cope?

Day surgery is seen as beneficial to patients. However, follow-up interviews conducted in the home in the week after day surgery in this small study have revealed unexpected problems relating to analgesia, patient information, mobilisation and pressure to return to work. The research findings serve as a reminder that one-day surgery does not mean one-day recovery.

Promoter binding factors regulating cyclin B transcription in the sea urchin embryo.

Cyclin B is a key regulatory protein of the cell cycle, central to the control of the G2/M transition. In the developing sea urchin embryo, the cyclin B gene is transcriptionally regulated in concert with changing patterns of cell division. In an effort to understand the mechanism controlling cyclin B expression during development, we have conducted an analysis of the Strongylocentrotus purpuratus cyclin B gene promoter. DNase I foot-printing of the cyclin B upstream region revealed eight binding regions within 435 bp of the start of transcription; seven of these sites were within 215 bp. Found within these regions were consensus sequences for two CCAAT boxes, TATA, and E-boxes and sequences with some similarity to E2F and octamer binding motifs. Upstream sequences were functionally defined by generating cyclin B-CAT fusion genes, containing deletions and base specific mutations, and testing for relative levels of expression by gene transfer. Both CCAAT boxes were found to be essential for maximal levels of expression. A third binding site (PR7) with no recognizable consensus sequence was also found to act as a positive element. Our results suggest that protein binding to the E2F-like sequences may act to reduce expression. Protein binding was further characterized by gel mobility-shift and methylation interference. The CCAAT boxes were found to bind similar, if not identical, proteins. Sequence comparisons and methylation interference data indicate that the likely protein binding these CCAAT sequences is the characterized CCAAT-binding protein CP1. A probe containing site PR7 formed multiple gel shift complexes that, by methylation interference, appeared to be interrelated. One major complex was formed with an oligonucleotide containing the two E2F-like sequences. Protein binding to this probe was specific and required bases within the E2F-like sequences. Our results indicate that cyclin B is subject to positive and negative regulation, involving multiple factors that bind between -200 and -90 bp from the start of transcription.

Impact of a thrombolysis research trial on time to treatment for acute myocardial infarction in the emergency department.

Because time to treatment in AMI is a critical factor in long-term outcome, it is important that complex trials designed to improve reperfusion therapy do not delay the time to treatment. Participation in the TIMI 5 trial did not significantly prolong our door-to-needle time. These results indicate that, if done carefully, complex, labor-intensive studies can be performed within a reasonable time limit. Care should be taken to design protocols incorporating easy drug preparation, informed consent by the ED, and efficiency of trial initiation.

Bifunctional glyoxylate cycle protein of Caenorhabditis elegans: a developmentally regulated protein of intestine and muscle.

The reaction of an abundant 106-kDa polypeptide with a specific monoclonal antibody has been localized in intestinal and muscle cells of the nematode Caenorhabditis elegans. This protein was first detected in 4-6 cells of the clonal E lineage of 100-cell embryos. This lineage is committed to the intestinal cell fate. The antigen continued to be expressed in the differentiating gut and then appeared in early differentiating body wall muscle cells of 400- to 500-cell embryos. Molecular cloning and sequencing showed that the largest cDNA clone contained 3274 bp and encoded a sequence of 1005 amino acids. The predicted polypeptide of 112,799 MW contains separate domains for the glyoxylate cycle enzymes isocitrate lyase and malate synthase. Their enzymatic activities had been shown previously to be highest in embryos and L1 larvae (Khan, F. R., and McFadden, B. A. (1980). FEBS Lett. 115, 312-314; Khan, F. R., and McFadden, B. A. (1982). Exp. Parasitol. 54, 48-54; Wadsworth, W. G., and Riddle, D. L. (1989). Dev. Biol. 132, 167-173). The domain-specific sequences were shown to be contiguous in genomic DNA and are separated by an intron of 68 bp. A single polypeptide and both enzymatic activities are precipitated by the antibody, and peptide fragments resulting from limited proteolytic digestion contained amino acid sequences which overlap the predicted junctional region. The physical localization of the gene correlates with a small region of the left arm of Linkage Group V to which multiple embryonic lethal mutations have been mapped.

The role of the CCAAT/enhancer-binding protein in the transcriptional regulation of the gene for phosphoenolpyruvate carboxykinase (GTP).

Previous studies have identified a region in the promoter of the gene for phosphoenolpyruvate carboxykinase (GTP) (PEPCK) (positions -460 to +73) containing the regulatory elements which respond to cyclic AMP, glucocorticoids, and insulin and confer the tissue- and developmental stage-specific properties to the gene. We report that CCAAT/enhancer-binding protein (C/EBP) binds to the cyclic AMP-responsive element CRE-1 as well as to two regions which have been previously shown to bind proteins enriched in liver nuclei. The DNase I footprint pattern provided by the recombinant C/EBP was identical to that produced by a 43-kDa protein purified from rat liver nuclear extracts, using a CRE oligonucleotide affinity column, which was originally thought to be the CRE-binding protein CREB. Transient contransfection experiments using a C/EBP expression vector demonstrated that C/EBP could trans activate the PEPCK promoter. The trans activation occurred through both the upstream, liver-specific protein-binding domains and the CRE. The CRE-binding protein bound only to CRE-1 and not to the upstream C/EBP-binding sites. The results of this study, along with physiological properties of C/EBP, indicate an important role for this transcription factor in providing the PEPCK gene with several of its regulatory characteristics.

Anomalous origin of the right coronary high above the left sinus of Valsalva.

Anomalous origin of the right coronary artery from the ascending aorta above the left sinus of Valsalva is exceedingly rare and previously has been reported to be associated with congenital aortic valve disease. We report a case of the right coronary artery arising from the mid ascending aorta, high above the left sinus, with a clinically and angiographically normal aortic valve.

Retropharyngeal hematoma as a new cause of acute upper airway obstruction in rheumatoid arthritis.

A patient with severe rheumatoid arthritis (RA) receiving chronic anticoagulation therapy developed acute life threatening airway obstruction. The source of obstruction was a retropharyngeal hematoma compressing the upper airway rather than acute laryngeal dysfunction from the patient's RA. Our case illustrates a new cause of acute stridor and airway obstruction in RA. Publications on upper airway obstruction in RA and airway obstruction secondary to retropharyngeal hematoma are discussed.

Inherent laxity in total knee prostheses.

The anterior-posterior and rotatory laxities of 14 total knee prosthesis designs were measured in a loading rig with compressive, shear, and torque loads representative of physiologic loads. The measured laxities covered a wide range, both greater and smaller than that of the anatomic knee. This range was mainly due to the curvature or flatness of the plastic tibial surface and conformity with the femoral component. Pressure patterns showed the corresponding contact track and area on the tibial surfaces. It is proposed that for normal function, the laxity of the device should complement the remaining anatomic structures to produce a combined laxity resembling that of the normal knee. Excessive prosthetic laxity will lead to the risk of instability, soft tissue attenuation, edge-loading on components, and high contact stresses on the plastic. Inadequate prosthetic laxity may lead to altered kinematics and excessive stresses at the interface, running the risk of long-term loosening. The authors show the laxities of many currently used devices, providing important background information for assessing the role intrinsic prosthetic constraint might play in total joint performance in clinical analyses.