Syngnathoid Evolutionary History and the Conundrum of Fossil Misplacement.

Seahorses, pipefishes, trumpetfishes, shrimpfishes, and allies are a speciose, globally distributed clade of fishes that have evolved a large number of unusual body plans. The clade that includes all these forms, Syngnathoidei, has become a model for the study of life history evolution, population biology, and biogeography. Yet, the timeline of syngnathoid evolution has remained highly contentious. This debate is largely attributable to the nature of the syngnathoid fossil record, which is both poorly described and patchy for several major lineages. Although fossil syngnathoids have been used to calibrate molecular phylogenies, the interrelationships of extinct species and their affinities to major living syngnathoid clades have scarcely been quantitatively tested. Here, I use an expanded morphological dataset to reconstruct the evolutionary relationships and clade ages of fossil and extant syngnathoids. Phylogenies generated using different analytical methodologies are largely congruent with molecular phylogenetic trees of Syngnathoidei but consistently find novel placements for several key taxa used as fossil calibrators in phylogenomic studies. Tip-dating of the syngnathoid phylogeny finds a timeline for their evolution that differs slightly from the one inferred using molecular trees but is generally congruent with a post-Cretaceous diversification event. These results emphasize the importance of quantitatively testing the relationships of fossil species, particularly when they are critical to assessing divergence times.

Can local vibration alter the contribution of persistent inward currents to human motoneuron firing?

The response of spinal motoneurons to synaptic input greatly depends on the activation of persistent inward currents (PICs), which in turn are enhanced by the neuromodulators serotonin and noradrenaline. Local vibration (LV) induces excitatory Ia input onto motoneurons and may alter neuromodulatory inputs. Therefore, we investigated whether LV influences the contribution of PICs to motoneuron firing. This was assessed in voluntary contractions with concurrent, ongoing LV, as well as after a bout of prolonged LV. High-density surface electromyograms (HD-EMG) of the tibialis anterior were recorded with a 64-electrode matrix. Twenty males performed isometric, triangular, dorsiflexion contractions to 20% and 50% of maximal torque at baseline, during LV of the tibialis anterior muscle, and after 30-min of LV. HD-EMG signals were decomposed, and motor units tracked across time points to estimate PICs through a paired motor unit analysis, which quantifies motor unit recruitment-derecruitment hysteresis (ΔF). During ongoing LV, ΔF was lower for both 20% and 50% ramps. Although significant changes in ΔF were not observed after prolonged LV, a differential effect across the motoneuron pool was observed. This study demonstrates that PICs can be non-pharmacologically modulated by LV. Given that LV leads to reflexive motor unit activation, it is postulated that lower PIC contribution to motoneuron firing during ongoing LV results from decreased neuromodulatory inputs associated with lower descending corticospinal drive. A differential effect in motoneurons of different recruitment thresholds after prolonged LV is provocative, challenging the interpretation of previous observations and motivating future investigations. KEY POINTS: Neuromodulatory inputs from the brainstem influence motoneuron intrinsic excitability through activation of persistent inward currents (PICs). PICs make motoneurons more responsive to excitatory input. We demonstrate that vibration applied on the muscle modulates the contribution of PICs to motoneuron firing, as observed through analysis of the firing of single motor units. The effects of PICs on motoneuron firing were lower when vibration was concurrently applied during voluntary ramp contractions, likely due to lower levels of neuromodulation. Additionally, prolonged exposure to vibration led to differential effects of lower- vs. higher-threshold motor units on PICs, with lower-threshold motor units tending to present an increased and higher-threshold motor units a decreased contribution of PICs to motoneuron firing. These results demonstrate that muscle vibration has the potential to influence the effects of neuromodulation on motoneuron firing. The potential of using vibration as a non-pharmacological neuromodulatory intervention should be further investigated.

Misinterpretation of TPMT by a DTC genetic testing company.

23andme has suspended marketing of health-related reports due to US Food and Drug Administration approval violations. This has fostered discussions on the actual risks associated with consumer use of these reports. In the case described below, rare genotypes for the gene encoding thiopurine methyltransferase (TPMT) were misinterpreted by a direct-to-consumer (DTC) company, and risk calculations for breast cancer were offered when accuracy was not possible from the available information. Politics aside, these examples illustrate risks associated with DTC genetic testing without professional interpretation.

Concordance between site of onset and limb dominance in amyotrophic lateral sclerosis.

BACKGROUND: Focality of onset of amyotrophic lateral sclerosis (ALS) is not understood. Attempts to implicate physical exercise in the aetiology of ALS have provided inconsistent results. If physical use of a limb were important in defining the site of onset, then handedness might be expected to influence the side of upper limb-onset disease and footedness likewise in lower limb-onset ALS. METHODS: ALS patients registered with an internet-based support site were invited to complete an online questionnaire concerning site of onset of symptoms and their dominant hand and foot. A binomial test of proportions was used to investigate the null hypothesis that handedness and footedness do not influence side of onset in upper and lower limb-onset ALS, respectively. RESULTS: 343 ALS patients with limb-onset disease were studied. For upper limb-onset patients, there was concordance for side of onset and handedness (64%; p<0.0006). For lower limb-onset patients, concordance for side of onset and footedness was absent. The frequency of left handedness was commensurate with that found in the general population. INTERPRETATION: These results are potentially consistent with the hypothesis that exercise influences pathogenesis in ALS since routine physical demands on the upper limb are heavily influenced by limb dominance, whereas in the lower limbs the commonest function is standing or locomotion, which uses both legs equally. However, there may also be an inherent cortical vulnerability underlying upper limb-onset laterality, possibly influenced by changes in neuronal connectivity and cortical excitability in relation to handedness and reflected by the "split hand" phenomenon consistently observed in ALS.

A mediator of cell surface-specific plasmin generation.

It has become increasingly evident that the generation of cell surface proteases including plasmin is fundamental to a wide variety of in vivo biological processes. Cell surface receptors allow for specific controlled proteolysis, provide protection from inhibitors, and enhance catalytic efficiency. Here we describe one such receptor, annexin II, which serves as a coreceptor for tissue plasminogen activator and plasminogen and is found on a wide variety of cell types including endothelial cells, some tumor cells, monocytes and macrophages, and neuronal cells. Evidence indicates that annexin II may be crucial to the efficient generation of cell surface plasmin, endothelial cell formation of new blood vessels, and maintenance of vascular patency. Additionally, it has been shown that annexin II expression in acute promyelocytic leukemia contributes to the bleeding diathesis seen in this disease and that inhibition of annexin II may be an important mechanism in the formation of atherosclerotic plaque. Furthermore, emerging evidence reveals the importance of annexin II on the surface of monocytes and macrophages, where it may contribute to the cells' ability to degrade extracellular matrix proteins and migrate to sites of injury or inflammation.

Regeneration of intrabony defects: comparing e-PTFE membrane vs. decalcified freeze dried bone allograft--a pilot study.

The purpose of this study was to compare the amount of clinical attachment gained when using an expanded polytetrafluoroethylene (e-PTFE) membrane versus the placement of a decalcified, freeze-dried bone allograft (DFDBA) in human deep intrabony defects. Ten 2- and 3-wall intrabony defects were treated with scaling and root planing followed by flap surgery and placement of either an e-PTFE membrane or a DFDBA. The clinical parameters, clinical attachment level (CAL), probing depth (PD) and recession, were evaluated at baseline, following oral hygiene instructions and scaling and root planing, and at 6 and 9 months post-operatively. The e-PTFE group demonstrated an increased CAL of 3.2 mm at 6 months and 3.4 mm at 9 months while the DFDBA group manifested a gain of 2.2 mm at 6 months and 2.6 mm at 9 months. The e-PTFE group had a 6.6 mm decrease in PD at 6 months and 6.2 mm at 9 months while the DFDBA group had a decrease of 4.0 mm and 4.4 mm at 6 and 9 months respectively. The amount of gingival recession was 1.6 mm for both groups at 6 months and slightly less for the PTFE group at 9 months. It was concluded that both treatment groups resulted in a clinically and statistically significant improvement over baseline measurements in clinical attachment gain and PD reduction. No statistical significance could be demonstrated between the two groups. The number of subjects and sites treated by the two treatment modalities--e-PTFE and DFDBA--was too small to conclude that the treatments gave comparable results. A larger sample size is necessary in order to establish whether or not a statistically significant difference exists between groups.

Osseous repair of a lateral periodontal cyst.

THE LATERAL PERIODONTAL CYSTS is a slow-growing radiolucent, developmental lesion occurring most frequently in males during the sixth decade. As part of the differential diagnosis, it must be distinguished from the collateral keratocyst and the gingival cyst of adults as well as other entities. Speculation remains as to the lateral periodontal cyst's developmental origin. Whether it is from reduced enamel epithelium, remnants of dental lamina, or cell rests of Malassez remains to be determined. The following longitudinal case report describes the review of literature and clinical and histologic findings as well as unusual treatment of a through-and-through perforating lateral periodontal cyst. Due to the large bony defect left after the cyst's removal, a decalcified freeze-dried bone graft was placed to close the defect. The repair of the lesion was followed for 30 months.

Effect of a twice daily 0.12% chlorhexidine rinse on the oral health of a geriatric population.

The inhibitory effect of a chlorhexidine rinse on gingival inflammation and plaque accumulation has been well documented. The purpose of this study was to determine whether a twice daily oral rinse with 0.12% chlorhexidine will resolve denture-associated inflammation in a geriatric population. Thirty-six subjects, average age 83 years, were randomly divided into two groups, active and control, and further stratified into three subgroups, removable partial dentures, complete overdentures and lacking a removable prosthesis. Gingival (Löe and Silness '63) and plaque (Silness and Löe '64) indexes were performed on teeth Nos 3, 9, 12, 19, 25 and 28 at baseline and at 60 days. The subjects, following baseline measurements, were required to rinse twice daily for 30 seconds with either a 15 ml solution of 0.12% chlorhexidine or a placebo and instructed to continue their normal oral hygiene routine. The data were statistically analyzed. When active and control groups were compared, either in total or within their stratified subdivisions, significant differences were observed (P less than 0.001). The active group had a 10.27% and 16.68% reduction in the gingival and plaque indexes, respectively, compared to insignificant changes in the control groups. It was concluded that although chlorhexidine proved effective in reducing inflammation and plaque scores, this reduction was not influenced by the type of prosthesis worn.

Irrigation with chlorhexidine to resolve naturally occurring gingivitis. A methodologic study.

This study compared oral irrigation and rinsing with chlorhexidine (CHX) and placebo in the treatment of naturally occurring chronic gingivitis. 44 subjects with at least 6 interproximal sites which bled on probing were randomly distributed on a double-blind basis into 4 treatment groups, placebo-rinse, CHX-rinse (0.12%), placebo-irrigation and CHX-irrigation (0.06%). A half-mouth was scaled 2 weeks prior to therapy in all groups. Rinses were performed 2 times daily and irrigation was performed once a day by means of an oral irrigator with the tip directed at a right angle to the tooth. Subjects continued with routine oral hygiene without instruction. The active treatment period was 2 months. Parameters were recorded at baseline and at 60 days. At the conclusion, marginal plaque was cultured for predominant microbial types. CHX-rinse (0.12%) and CHX-irrigation (0.06%) significantly reduced (p less than 0.05) plaque. Gingival bleeding decreased by 26% in both scaled and unscaled sites following CHX (0.12%) rinses and by 40% at both types of sites following CHX (0.06%) irrigation. Bleeding was reduced with CHX-irrigation greater (p less than 0.05) than with the placebo-irrigation. The mean log of colony-forming units of Actinomyces species was significantly lower (p less than 0.05) in the CHX (0.12%) rinse and CHX (0.06%) irrigator groups than in the placebo groups. These data therefore indicate that delivery of CHX (0.06%) by an oral irrigator is an effective means of treating naturally occurring gingivitis.

Antimicrobial agents in the prevention and treatment of periodontal diseases.

It has been estimated that there are more than 400 diseases affecting the oral cavity. In terms of prevalence, however, the major public health problems are caries and periodontal disease. Although these two destructive entities are completely different in many respects, they share a common denominator: the initial lesions are brought about by an aggregate of bacteria known as plaque. This article discusses chemical control of plaque in the treatment of gingivitis and antimicrobial control of subgingival plaque in the treatment of periodontitis. The authors address the use of antibiotics in the treatment of localized juvenile periodontitis, the ideal properties of antiplaque agents, and adjunctive subgingival application of antimicrobial agents.

Hydroxylapatite as an alloplastic graft in the treatment of human periodontal osseous defects.

Twelve patients, 32 to 60 years of age, received a polycrystalline ceramic form of pure dense hydroxylapatite as an alloplastic bone implant material in intrabony defects following reflection of full mucoperiosteal flaps, root planing and defect-curettement. The defects were measured from an acrylic stent, using an endodontic silver point which was placed to the base of the defect. Similarly, debrided and curetted defects in the same patients were not implanted and served as controls. Recalls for documentation and plaque control were at 1, 2, and 4 weeks, and at 3, 6 and 9 months. Measurements relating to changes in defect-depth were made upon reentry at 9 months. The twelve defects, serving as controls, showed very little difference between the pretherapy and 9-month measurements. The initial mean measurement from the base of the defect to the highest alveolar crest was 4.27 mm and the 9-month mean measurement after curettage only was 3.36 mm. In terms of resolution of the original defect this amounted to 19.49% reduction, but a 0.46-mm mean loss in height of the alveolar crest provided an actual percentage fill of the original defect of 9.91%. Of sixteen experimental defects, the same initial mean measurement from the base of the defect to the highest alveolar crest was 5.18 mm and the 9-month mean measurement after grafting was 2.43 mm. In terms of resolution of the original defect, this amounted to a 53.57% reduction, but in contradistinction to the curettage sites, a mean increase in height of the highest alveolar crest of 0.61 mm gave a true percentage fill of the original defect of 66.89%. At the 9-month reentry, the implanted mass seemed to be partially "calcified" and was resistant to penetration with a probe or removal with a curette. The data and clinical impression strongly suggest that hydroxylapatite has a potential as an alloplastic implant with clinically apparent acceptance by the soft and hard tissues.

The relationship between the mobility of human teeth and their supracrestal fiber support.

A method to study the relationship between the mobility of human teeth and their supracrestal fiber support was developed. The results of this study would indicate that: (1) The supracrestal fibers do not contribute significantly to the support of a normal premolar tooth. (2) As a human premolar tooth develops moderate to severe loss of osseous support, the relative contribution of the supracrestal fibers to the support of the tooth increases significantly.

The pregnant adolescent--a group approach.

This paper has described the groups for pregnant teenagers developed in the Rochester Adolescent Maternity Project. One and one-half year's experience with these groups has allowed the authors time to begin their study of groups and to write a descriptive paper of their evolution. The groups' development goes on while the leaders continue their own theoretical study of groups at this writing. Groups for pregnant adolescents have ranged from group therapy sessions to structured groups where only didactic material is presented. The literature is somewhat limited in its discussion of types of groups and especially in describing group process. This paper differs from others in that both group structure and process, based on the group objectives, are discussed. Information on approaches beneficial to the adolescent have been included. The goals of the group are to help the teenagers work through the developmental tasks of adolescence and pregnancy and to prepare them for the labor, delivery, and initial parenthood experience. Group structure is based on the intent to engage teenagers in resolution of these tasks in order to be prepared at a variety of levels, i.e. cognitive, emotional, etc., for labor, delivery, and parenthood. Co-leadership of the groups and an unstructured format facilitate the movement of the group toward accomplishment of its objectives. Group content issues were explored and techniques developed to handle these issues were suggested. Included were the following: 1. Commitment to the group by the members is assisted by the structure set for the group and the leaders' active outreach to members. 2. Descriptions of emotions and thoughts are made in concrete rather than abstract terms because of the developmental status of the teenagers. 3. Expression of personal feelings, often difficult for teenagers, is aided by the use of a projective technique. 4. Transition from leader-oriented to group-directed discussion is made possible by the group leaders gradually changing their leadership from one of direct interaction to one of facilitating discussion. 5. Polarization of the group in a negative or positive direction is prevented through the use of a neutral group member or active intervention by the group leaders taking on a neltral role. 6. Control, an issue of pregnancy and adolescence, is dealt with on interactional, educational, and emotional levels. 7. Termination is determined by the stage of the group "work" and is identified and facilitated by the group leaders. Research questions needed to document the effectiveness of the group approach to the pregnant adolescent were addressed.