A gain-of-function screen for genes controlling motor axon guidance and synaptogenesis in Drosophila.

BACKGROUND: The neuromuscular system of the Drosophila larva contains a small number of identified motor neurons that make genetically defined synaptic connections with muscle fibers. We drove high-level expression of genes in these motor neurons by crossing 2293 GAL4-driven EP element lines with known insertion site sequences to lines containing a pan-neuronal GAL4 source and UAS-green fluorescent protein elements. This allowed visualization of every synapse in the neuromuscular system in live larvae. RESULTS: We identified 114 EPs that generate axon guidance and/or synaptogenesis phenotypes in F1 EP x driver larvae. Analysis of genomic regions adjacent to these EPs defined 76 genes that exhibit neuromuscular gain-of-function phenotypes. Forty-one of these (known genes) have published mutant alleles; the other 35 (new genes) have not yet been characterized genetically. To assess the roles of the known genes, we surveyed published data on their phenotypes and expression patterns. We also examined loss-of-function mutants ourselves, identifying new guidance and synaptogenesis phenotypes for eight genes. At least three quarters of the known genes are important for nervous system development and/or function in wild-type flies. CONCLUSIONS: Known genes, new genes, and a set of previously analyzed genes with phenotypes in the Adh region display similar patterns of homology to sequences in other species and have equivalent EST representations. We infer from these results that most new genes will also have nervous system loss-of-function phenotypes. The proteins encoded by the 76 identified genes include GTPase regulators, vesicle trafficking proteins, kinases, and RNA binding proteins.

The impact of home computer use on children's activities and development.

The increasing amount of time children are spending on computers at home and school has raised questions about how the use of computer technology may make a difference in their lives--from helping with homework to causing depression to encouraging violent behavior. This article provides an overview of the limited research on the effects of home computer use on children's physical, cognitive, and social development. Initial research suggests, for example, that access to computers increases the total amount of time children spend in front of a television or computer screen at the expense of other activities, thereby putting them at risk for obesity. At the same time, cognitive research suggests that playing computer games can be an important building block to computer literacy because it enhances children's ability to read and visualize images in three-dimensional space and track multiple images simultaneously. The limited evidence available also indicates that home computer use is linked to slightly better academic performance. The research findings are more mixed, however, regarding the effects on children's social development. Although little evidence indicates that the moderate use of computers to play games has a negative impact on children's friendships and family relationships, recent survey data show that increased use of the Internet may be linked to increases in loneliness and depression. Of most concern are the findings that playing violent computer games may increase aggressiveness and desensitize a child to suffering, and that the use of computers may blur a child's ability to distinguish real life from simulation. The authors conclude that more systematic research is needed in these areas to help parents and policymakers maximize the positive effects and to minimize the negative effects of home computers in children's lives.

Use of immediately loaded press-fit cylinder implants in oral reconstruction.

Press-fit implants can be used to meet the prosthetic needs of patients who require immediate loading of their implants. This procedure may be necessary because of a patient's unwillingness and/or inability to tolerate a removable prosthesis. The implants reported in this study had a similar success rate to those immediately loaded screw-type implants previously reported by others. The lack of large numbers of long-term immediately loaded implants dictates the need for detailed informed consent when using immediately loaded cylinder implants for dental reconstruction.

Team approach for closure of oroantral and oronasal fistulae.

Oroantral and oronasal fistulas present with a broad range of causation, size, duration, and extent of infection involving the nose and paranasal sinuses. Accurate diagnosis of the extent of the disease with appropriate radiographic evaluation will guide the surgeon to select an approach that addresses all of the infected sites. When significant sinus disease is found, an endoscopic approach to restoring drainage in all of the involved sinuses can promote predictably successful closure of oroantral and oronasal fistulas. The multispecialty team approach to this disease, with the concomitant management of the sinusitis and fistula closure, is a significant advance in the successful management of this chronic condition.

The incidence of altered sensation of the mental nerve after mandibular implant placement.

PURPOSE: This study was designed to determine the incidence of altered sensation in patients undergoing mandibular endosseous implant placement. PATIENTS AND METHODS: Ninety-four consecutive patients who underwent the placement of mandibular implants constituted the study group. The only patients that were excluded from this study were those who had preexisting injury to the trigeminal nerve. Patients were followed using standard neurologic testing during the period immediately following implant placement through 6 months. Four hundred five implants were placed in 43 female and 51 male patients. Implant length selection was based on panoramic radiographs using known markers to correct for distortion. In 13 of the patients, the mandibular canal was not adequately visualized, and a computed tomography (CT) scan was used to plan the implant locations. Implants were selected to be located 2 mm above the inferior alveolar canal based on the panoramic images and 1 mm above the canal based on CT images. RESULTS: Eight patients reported altered nerve sensation at their first postimplant visit (8.5%). None of the patients experienced hyperesthesia or dysesthesia. Four of the eight patients with altered sensation had no objective findings or decreased nerve function. One of the patients remained totally anesthetic for 2 months, but reported return to normal function at 4 months. CONCLUSIONS: These findings indicate that a small percentage of patients experience altered sensation after the placement of mandibular endosseous implants. Unlike previous studies, no permanent altered sensation was found. By using proper treatment planning, one can offer endosseous implants with minimal risk of injury to the trigeminal nerve.

Internet paradox. A social technology that reduces social involvement and psychological well-being?

The Internet could change the lives of average citizens as much as did the telephone in the early part of the 20th century and television in the 1950s and 1960s. Researchers and social critics are debating whether the Internet is improving or harming participation in community life and social relationships. This research examined the social and psychological impact of the Internet on 169 people in 73 households during their first 1 to 2 years on-line. We used longitudinal data to examine the effects of the Internet on social involvement and psychological well-being. In this sample, the Internet was used extensively for communication. Nonetheless, greater use of the Internet was associated with declines in participants' communication with family members in the household, declines in the size of their social circle, and increases in their depression and loneliness. These findings have implications for research, for public policy and for the design of technology.

Location of incisive canal in relation to central incisor implants.

Computerized tomography (CT) scanning, now widely used for the diagnosis and treatment planning of dental implant sites, can be more specifically useful with integrated computer software. In this instance, the potentially critical incisive foramen area at the premaxilla is analyzed to better under stand its configuration and volume relative to the placement of root-form implants.

Interactive CT diagnostics, planning and preparation for dental implants.

The insertion of dental implants is multifaceted. Adequate containment of the implant body requires not only a measurable volume of bone but also an acceptable density of this osseous foundation. Through interactive computerized axial tomography (CAT), not only are such measurements conveyed to the clinician, but vital structures that should be avoided or at least accounted for are portrayed in a three-dimensional manner. Predict-ability is enhanced, and the implants can be directed for prosthetic use in conjunction with surgical guides (templates).

Endoresection of the iris and ciliary body in epithelial downgrowth.

We present a case of epithelial downgrowth with intractable glaucoma after multiple intraocular surgeries. The eye was successfully managed with a pars plana approach. The iris and epithelial tissue over the ciliary body were removed with intraocular scissors and a vitrector combined with unipolar diathermy and endophotocoagulation. The use of moderate hypotensive anesthesia may have helped prevent intraoperative hemorrhage. During more than 3 years of follow-up, intraocular pressure ranged from 13 to 19 mm Hg, visual acuity was 20/80 with aphakic correction with a rigid gas-permeable lens, and there was no recurrence of epithelial downgrowth.

On the roles of inscuteable in asymmetric cell divisions in Drosophila.

Three processes requiring insc, protein localization, RNA localization, and mitotic spindle orientation, appear to be tightly correlated but nevertheless independent. The apical cortical localization of Insc protein occurs prior to mitosis and precedes the basal localization of Pros, Numb, and pros RNA. In insc null mutants, neuroblasts divide in more random orientations and fail to correctly localize Pros, Numb, and pros RNA to their correct position during mitosis. Our results suggest that asymmetric localization of Insc during interphase functions to establish positional information for spindle orientation and the basal localization of Numb, Pros, and pros RNA during mitosis. Insc probably interacts with a number of interacting partners in order to effect its various functions. One of its partners, Stau, is involved exclusively in the process of RNA localization.

Effect of supplemental gases on end-tidal CO2 and oxygen saturation in patients undergoing fentanyl and midazolam outpatient sedation.

Forty-six American Society of Anesthesiologists Class I and II adults were randomly assigned to one to two study groups. Each subject received 0.7 microgram/kg of fentanyl and a titrated dose of midazolam. One group received 100% supplemental oxygen (O2) while another group received 50% nitrous oxide (N2O) and 50% O2. End-tidal carbon dioxide (EtCO2) and O2 saturation (SpO2) were measured at 5-min intervals throughout the procedure. We conclude that there was no significant difference in EtCO2 or O2 saturation between the two groups.

Role of inscuteable in orienting asymmetric cell divisions in Drosophila.

Drosophila neuroblasts and epithelial cells in the procephalic neurogenic region divide perpendicular to the surface, and segregate the proteins Numb and Prospero into the basal daughter cell. We demonstrate here that orientation of the mitotic spindle and correct localization of Numb and Prospero in these cells require the inscuteable gene. Moreover, ectopic expression of inscuteable in other epithelial cells leads to spindle reorientation. The Inscuteable protein localizes to the apical cell cortex before mitosis, suggesting that Inscuteable functions in establishing polarity for asymmetric cell division.