Fracture and displacement of lingual cortical plate of mandibular symphysis following bone harvesting: case report

This article describes a unique complication after chin bone harvesting. The complication consisted of fracture and posterior displacement of the lingual cortical plate that did not occur at the time of the operation but during the healing phase. The bone was harvested for a bilateral sinus lift procedure. Diagnosis was made by chance with the aid of a postoperative CT scan that was taken to study the sinus area. The mandibular scans revealed a bony fragment 2 to 4 mm in width and 3 cm in length fractured and displaced 1 cm posteriorly. This bony fragment was pedicled to the geniohyoid and genioglossus muscles. The patient was asymptomatic, and no treatment was carried out. The patient is still symptom-free 16 months after the initial diagnosis of the fracture.     

Deciduous dentition in the rabbit (Oryctolagus cuniculus). A roentgenographic study

The sequence and chronology of deciduous tooth eruption and exfoliation in the rabbit was studied roentgenographically. In the mandible, two molars are erupted at 25 days gestation age. Root resorption of these teeth is apparent by the 7th postnatal day and both have been exfoliated by the 30th day. Development is more variable in the maxillary arch. Two molars and the second incisor tooth are erupted at 25 days gestation age and a third, more anteriorly placed, molar erupts by the 7th postnatal day. All of the maxillary teeth have been exfoliated by the 35th day. Transitory predecessors of the large permanent anterior incisor teeth in both jaws, reported in the literature, were not seen radiographically in our series. The deciduous dental formula, including the first incisors, may be stated: $\text{I}\text{(}\text{ab}\text{a}\text{)}\text{C}\text{(}\text{o}\text{o}\text{)}\text{M}\text{(}\text{def}\text{ef}\text{)}$, with $\text{d}$ the late erupting maxillary molar. The dentition of the rabbit differs from that of other commonly used laboratory animals in two important respects: (a) the deciduous dentition persists for about 1 month postnatally before being completely exfoliated; and (b) all of the permanent teeth are of the continuously erupting variety.     

Systemic physostigmine increases the antinociceptive effect of spinal morphine

In this study we evaluated the antinociceptive effect of concurrent intrathecal (i.t.) and subcutaneous (s.c.) administration of morphine and physostigmine, respectively. The experiments were performed on male Wistar rats. Intrathecal administration of morphine was performed through a catheter implanted in the subarachnoid space. The ‘tail-immersion' test was used to measure animals' responses to evoked nociceptive stimuli. Interaction of drugs was analyzed using a dose addition model. Both i.t. (1–5 μg) administration of morphine and s.c. (50–250 μg/kg) administration of physostigmine increased the latencies of nociceptive responses in a dose-dependent manner. Two micrograms of i.t. morphine and 100 μg/kg of s.c. physostigmine demonstrated 31.6±10.6 and 34.2±11.4 percentage of maximal possible effect (%MPE), respectively. Simultaneous administration of 1 μg of i.t. morphine and 50 μg/kg of s.c. physostigmine produced a %MPE equal to 84.8±16.9. Thus, combined administration of 1 μg i.t. morphine and 50 μg/kg s.c. physostigmine resulted in a strong, highly significant antinociceptive effect. This effect was much higher than the effect expected if both drugs acted in an additive manner. Supra-additive interaction observed in this study might be a result of simultaneous activation of different neurotransmitter systems involved in nociceptive processing at the spinal as well as at the supraspinal level of the CNS.     

From the Cover: Bats adjust their mouth gape to zoom their biosonar field of view

Active sensing, where sensory acquisition is actively modulated, is an inherent component of almost all sensory systems. Echolocating bats are a prime example of active sensing. They can rapidly adjust many of their biosonar parameters to optimize sensory acquisition. They dynamically adjust pulse design, pulse duration, and pulse rate within dozens of milliseconds according to the sensory information that is required for the task that they are performing. The least studied and least understood degree of freedom in echolocation is emission beamforming—the ability to change the shape of the sonar sound beam in a functional way. Such an ability could have a great impact on the bat’s control over its sensory perception. On the one hand, the bat could direct more energy into a narrow sector to zoom its biosonar field of view, and on the other hand, it could widen the beam to increase the space that it senses. We show that freely behaving bats constantly control their biosonar field of view in natural situations by rapidly adjusting their emitter aperture—the mouth gape. The bats dramatically narrowed the beam when entering a confined space, and they dramatically widened it within dozens of milliseconds when flying toward open space. Hence, mouth-emitting bats dynamically adjust their mouth gape to optimize the area that they sense with their echolocation system.The ability to actively adjust sensory acquisition is a key feature of almost all sensory systems. A capability to selectively control the sensory “field of view” could have a major impact on sensory perception. It would allow an animal to adjust the amount of acquired information in a task-dependent manner, zooming in on an object of interest and zooming out when a wider sector should be sensed. Many animals can shift their sensory attention (e.g., by changing gaze) or their focal plane (e.g., human vision), but there are no animals that are known to constantly adjust their sensory field of view under natural conditions. Echolocating bats perceive their environment acoustically by emitting ultrasonic pulses and analyzing the received echoes (1). The volume of space that is covered by the sound pulse and therefore, sensed by the bat depends on the emitted beamform—the spatial shape of the emission (2–9). Bats could potentially benefit greatly if they could change the form of their emitted beam in a functional manner, a property usually referred to in engineering as beamforming (10).Jakobsen and coworkers (11) recently summarized some of the reasons why a bat might narrow its biosonar beam. These reasons include (i) focusing sound into a narrower sector to improve the localization of objects, (ii) eliminating undesired echoes from the back or the sides of the bat, and (iii) increasing the sensing range by directing more energy forward. All of these come with a cost of reducing the volume of space that is scanned by the bat. It is, therefore, reasonable to expect that a bat would widen its beam under certain conditions, such as when scanning its surroundings during orientation or navigation.Most echolocating bats emit sound through the mouth (12). The biosonar beam of these bats can be modeled using the “piston model,” which represents a piston-shaped emitter in an infinite baffle (13). According to the piston model (and other emission models as well), a bat can adjust its beam by altering one of two parameters. First, it can change the spectral content of the sound pulse. Increasing the frequency would result in a narrower beam. Several bats that use frequency-modulated pulses seem to use this strategy at the terminal part of an attack on prey (3). Second, the bat can potentially change the aperture of its emitter. By opening its mouth wider, it can narrow the beam and vice versa. However, there is currently no direct evidence that bats change the emitter aperture for beamforming in this way.We studied beamforming in mouth-emitting Bodenheimer''s pipistrelle bats (Hypsugo bodenheimeri) under natural field conditions as well as in a controlled experimental setup. We started by recording and photographing bats as they came to drink at a small desert pond using an array of 12 ultrasonic microphones and a multiflash photography setup. Drinking on the wing requires fine maneuvering skills, which could benefit from active sensory adjustments (14, 15). When descending toward the pond and then ascending from it, the bats had to enter a confined space and then leave it, rapidly changing the degree of clutter around them—the density of nearby objects creating undesired echoes. To deal with these sensory challenges, we predicted that bats will alter their beamform while descending into the confined space or later, ascending out of it using one (or both) of the two mechanisms mentioned above. We used the audio recordings to reconstruct the bats’ emitted beams, and we measured their corresponding mouth gape in the images so that we could assess if and how bats control the beamform. To validate that our results were not a consequence of the drinking per se, we performed a second controlled experiment in which bats flew through a narrow (0.5 × 0.5-m² cross-section) 1.5-m-long tunnel and emerged from it into an open space environment (with less background echoes). We photographed the bats in flight to analyze their mouth gape and simultaneously recorded their echolocation pulses.We found that bats actively adjusted their beam by changing their mouth gape (i.e., the size of the emitter). Bats widened their mouth when entering a more confined cluttered environment, thus dramatically narrowing their beam width, and they narrowed the gape when flying toward the open, thus dramatically widening their beam. Bats that flew through a confined tunnel exhibited the same behavior—widening their mouth gape inside the tunnel and narrowing it when emerging into open space. We argue that this behavior aimed to functionally control the volume of the environment sensed by the bat to improve sensing—decreasing the scanned volume when entering a confined space and increasing it when flying into open space.     

Reply to Letter to the Editor: Pediatric Septic Arthritis and Osteomyelitis in the USA: A National KID Database Analysis

HSS Journal ® -     

Patient and provider determinants of breast cancer screening among Ontario women aged 40–49: a population-based retrospective cohort study

Breast Cancer Research and Treatment - Equivalent efficacy was demonstrated for the biosimilar CT-P6 and trastuzumab following neoadjuvant therapy for patients with human epidermal growth factor...