Selectively preventing development of third molars in rats using electrosurgical energy

BACKGROUND: Third molars are teeth with questionable value. People who never develop third molars avoid confronting the disease and pain these teeth often cause. Since third molars do not begin to develop until children are approximately five years of age, a window of opportunity exists to therapeutically prevent this tooth's development. The dentition of neonate rats possess developmental stages of molars similar to that of five-year-old children. This pilot study tests the hypothesis that third molars can be selectively prevented from developing. METHODS: Thirty-three neonate rats received a momentary pulse of electrosurgical energy to one of their maxillary tuberosities. The tuberosities on the contralateral sides received no treatment. Intraoral and radiographic examinations of sacrificed animals occurred when they were between 47 and 52 days old. Several tuberosity areas from sacrificed animals underwent histologic examination. RESULTS: Ten rats showed no intraoral or radiographic evidence of third molar development, and six developed smaller-than-normal third molars. Development of the maxilla also was affected frequently. One treated tuberosity area that was missing a third molar showed no histologic evidence of tooth-forming tissues, cyst formation or other significant abnormal tissue changes. CONCLUSIONS: Maxillary third molars can be selectively prevented from developing in rat pups at or near the time of tooth bud initiation; however, electrosurgical energy is too powerful and uncontrollable to reliably confine its damage to only the tooth-forming tissues. CLINICAL IMPLICATIONS: Third molars may be able to be selectively prevented from developing in growing children near the time of tooth bud initiation if less-differentiated precursor tooth-forming tissues can be selectively targeted.     

Cranial suture simulator for ultrasound diagnosis of craniosynostosis

Background: In evaluating the effectiveness of ultrasound as a screening tool for craniosynostosis it was discovered that sonologists and sonographers needed more experience scanning and visualizing cranial sutures on ultrasound. Objective: To create an ultrasound simulator to train radiologists and technologists to locate and recognize patent and fused cranial sutures in children. Materials and methods: The hypoechoic appearance of patent sutures was simulated by cutting lines into life-sized plastic doll heads and filling them with a commercial hypoechogenic material. Fused hyperechoic sutures were simulated by not cutting into the hard plastic region of a suture. The simulators teaching value was evaluated on three radiology residents and three fellows. Subjects performed pre-training scans on unknown simulators, received feedback and an opportunity to scan a training simulator, and then performed post-training scans on random unknown simulators. Accuracy was recorded as percentage of correctly demonstrated sutures. Results: The suture simulator reproduces the sonographic appearance of patent and fused cranial sutures. Accuracy of acquisition, interpretation, and overall diagnosis increased from 64 to 91%, 79 to 91%, 61 to 97%, respectively, between pre and post training scans. Conclusion: An ultrasound simulator can reproduce the appearance of patent and fused cranial sutures in children and can be used to train radiologists and technologists in the performance of a screening protocol.     

Speech recognition with a cochlear implant using triphasic charge-balanced pulses

OBJECTIVE: Typically, symmetrical charge-balanced biphasic current pulses are used in cochlear implants to ensure biological safety. Theoretically, monophasic pulses are more effective, but potentially noxious, stimuli. In this study we charge-balanced such monophasic pulses during selected non-stimulated intervals, effectively leading to triphasic pulses with a 4:1 amplitude ratio between the cathodic and anodic phases. Apart from ensuring safety, this is also expected to reduce power consumption and channel interaction. MATERIAL AND METHODS: Seven experienced Clarion CII cochlear implant users with a multichannel (12-16 channels) monopolar continuous interleaved sampling (CIS) strategy participated in the study. Three different CIS strategies were fitted using the Clarion Research Interface (CRI-2). The reference was an implementation of each subject's own CIS program. The two strategies tested used triphasic pulses on the same channels, one with half-wave rectification (TP-HWR) and one without rectification (TP-NoR) at the input. Directly after fitting (i.e. without any training), speech perception (phoneme score on consonant-vowel-consonant words) was measured in silence (sound-only) and in speech-shaped background noise with signal:noise ratios (SNRs) of +5 and 0 dB. RESULTS: Speech perception with the reference via the CRI-2 was equal to that of the free-field condition with the subjects' own speech processor. With the TP-NoR strategy, speech perception improved significantly (from 89% to 93%) in silence and in the 0-dB SNR condition (from 43% to 49%). With a SNR of +5 dB, performance was stable at approximately 66%. With the TP-HWR strategy, performance increased significantly in the 0- and +5-dB SNR conditions, to 55% and 74%, respectively. Power consumption was reduced in both strategies, to 30% and 36% for TP-HWR and TP-NoR, respectively. CONCLUSION: The new triphasic strategies are most promising, with respect to both their improved speech perception and reduced power requirements. The optimal parameters will have to be identified following long-term use.     

Pharyngeal entry through the vallecula

The authors describe a technique of entry into the vallecula with the guide of a small Deaver retractor inserted transorally, beyond the tongue base, into the vallecula. The tip of the Deaver directs the surgeon to the pharyngotomy site and allows pharyngeal entry and access without damaging structures in the region. This technique is particularly useful in total laryngectomy with or without pharyngectomy and is applicable whenever entry to the pharynx through the vallecula is indicated.     

Contraceptive effectiveness and safety of five nonoxynol-9 spermicides: a randomized trial

OBJECTIVES: To estimate and compare the effectiveness and safety of 5 spermicides over 6 and 7 months of use, respectively. The spermicides included 3 gels containing 52.5 mg, 100 mg, and 150 mg of nonoxynol-9 per dose and a film and a suppository, each containing 100 mg of nonoxynol-9 per dose. METHODS: Women wishing to use only spermicide for contraception for 7 months were randomly assigned to use 1 of the 5 spermicides with emergency contraception backup. Participants were followed up for up to 30 weeks after admission. RESULTS: Of 1,536 women enrolled, 868 (57%) either relied on the spermicide for 6 months or became pregnant. The probability of pregnancy during 6 months of typical use of the spermicide was 22% (95% confidence limits 16%, 28%) in the 52.5-mg gel group, 16% (10%, 21%) in the 100-mg gel group, 14% (9%, 19%) in the 150-mg gel group, 12% (7%, 17%) in the film group, and 10% (6%, 15%) in the suppository group. The pregnancy risk in the 52.5-mg gel group was significantly different (P <.05) from that in either of the other gel groups. The pregnancy risks in the three 100-mg product groups were not significantly different (P =.35). No significant differences among groups were found in the 7-month probability of specified urogenital conditions. CONCLUSION: The gel with the lowest amount of nonoxynol-9 was less effective than the 2 higher-dose gels. Among 3 products containing 100 mg of nonoxynol-9, formulation did not significantly affect pregnancy risk. All products were safe. LEVEL OF EVIDENCE: I     

Recombinant human erythropoietin as an adjunct to radiation therapy and cisplatin for stage IIB-IVA carcinoma of the cervix: a Southwest Oncology Group study

OBJECTIVE: The survival of cervix cancer patients is associated with their hemoglobin (Hgb) level during radiotherapy. The Southwest Oncology Group (SWOG) conducted a phase II trial to determine whether recombinant human erythropoietin (rHuEPO) safely corrects anemia during chemoradiotherapy for cervix cancer. METHODS: Patients had stage IIB-IVA cervix cancer and a Hgb between 8.0 and 12.5 g/dl. All patients received rHuEPO thrice weekly and oral iron starting 10-15 days before their 5-week course of whole pelvic irradiation and weekly cisplatin followed by intracavitary brachytherapy. RESULTS: Fifty-three patients from 26 institutions received the protocol treatment. The mean Hgb was 10.4 +/- 1.3 g/dl on the first day of rHuEPO administration (baseline), 11.0 +/- 1.6 g/dl on the first day of chemoradiotherapy, 11.6 +/- 1.9 g/dl at the midpoint of chemoradiotherapy, and 11.8 +/- 2.2 g/dl at the end of chemoradiotherapy. The target Hgb level of 12.5 g/dl was achieved in 40% of patients (95% CI 26-56%) by the midpoint of Chemoradiotheraphy. Change in Hgb was associated with baseline serum iron (P = 0.008) and transferrin saturation (P = 0.05) levels, but not with baseline Hgb or serum ferritin, or patient age. Seven patients developed deep vein thrombosis. Two-year progression-free survival (PFS) was 43% and overall survival (OS) was 51%. Survival was significantly associated with Hgb level at the end of chemoradiotherapy, but not with the baseline Hgb level. CONCLUSIONS: rHuEPO and iron gradually increased Hgb levels in anemic women with local advanced cervix cancer during chemoradiotherapy. There was a higher than expected incidence of deep vein thrombosis. The progression-free and overall survival rates were lower than reported for women with normal Hgb levels.