Increased perception of loudness in autism

Clinical reports on autism describe abnormal responses to auditory stimuli such as intolerance to sounds. The present study assessed subjective perception of loudness in subjects with autism compared to healthy controls, using two psychoacoustic tests. First, the auditory dynamic range was evaluated at six different tone frequencies. Secondly, loudness growth as a function of the intensity level of a 1 kHz tone was estimated. Verbal responses from a group of 11 children and adolescents with autism were compared to responses of 11 age- and gender- matched healthy controls. Smaller auditory dynamic ranges were found in the autistic group than in the control group, as well as increased perception of loudness, indicating hyperacusis in subjects with autism.     

Local dexamethasone therapy conserves hearing in an animal model of electrode insertion trauma-induced hearing loss.

HYPOTHESIS: The progressive loss of hearing that develops after electrode insertion trauma (EIT) can be attenuated by local dexamethasone (DXM) therapy. BACKGROUND: Hearing loss (HL) that develops after cochlear implant EIT occurs in two stages in laboratory animals, that is, an immediate loss followed by a progressive loss. Direct infusion of DXM into the guinea pig cochlea can attenuate both ototoxin- and noise-induced HL. MATERIALS AND METHODS: Auditory-evoked brainstem responses (ABRs) of guinea pigs were measured for 4 frequencies (i.e., 0.5, 1, 4, and 16 kHz) before, immediately after, and more than 30 days post-EIT for experimental (EIT,EIT + artificial perilymph, and EIT + DXM) and for the contralateral unoperated cochleae of each group. An electrode analog of 0.14-mm diameter was inserted through a basal turn cochleostomy for a depth of 3 mm and withdrawn. DXM in artificial perilymph was delivered immediately post-EIT into the scala tympani via a miniosmotic pump for 8 days. RESULTS: The ABR thresholds of EIT animals increased progressively post-EIT. Contralateral unoperated cochleae had no significant changes in ABR thresholds. Immediately post-EIT, that is, Day 0, the DXM-treated animals exhibited a significant HL at 1, 4, and 16 kHz, but this HL was no longer significant by Day 30 compared with contralateral control ears. CONCLUSION: The results from immediate local treatment of the cochlea with DXM in an animal model of EIT-induced HL suggest a novel therapeutic strategy for hearing conservation by attenuating the progressive HL that can result from the process of electrode array insertion during cochlear implantation.     

Evidence-based surgery in chronic pancreatitis

BACKGROUND: In the past two decades our knowledge of the pathophysiology and surgical treatment options in chronic pancreatitis has improved substantially. Surgical treatment in chronic pancreatitis has evolved from extending to organ-preserving procedures. DISCUSSION: The classical Whipple resection is no longer a standard procedure in chronic pancreatitis, and is continuously being replaced by operations such as the duodenum-preserving pancreatic head resection and pylorus-preserving Whipple. These procedures allow the preservation of exocrine and endocrine pancreatic function, provides pain relief in up to 90% of patients, and contributes to an improvement in life quality. CONCLUSIONS: In addition to presently available results from randomized controlled trials, new studies comparing available surgical approaches in chronic pancreatitis are needed to determine which procedure is the most effective in the treating chronic pancreatitis.     

Mandibular angle implants

A new type of implant designed to increase the angle of the mandible in three dimensions is described. Made of silicone and shaped like a saddle, this implant makes the technique of implantation relatively simple, and its versatility makes it a desirable addition to the tools for skeletal framework reconstruction of the face. The satisfaction rate has been high and the complications easy to manage. The surgical technique consists of an intraoral incision and the development of a subperiosteal pocket at the mandibular angle area, often performed under local anesthesia.     

Finite element model of the impaction of a press-fitted acetabular cup

Press-fit surgical procedures aim at providing primary stability to acetabular cup (AC) implants. Impact analysis constitutes a powerful approach to retrieve the AC implant insertion properties. The aim of this numerical study was to investigate the dynamic interaction occurring between the hammer, the ancillary and bone tissue during the impact and to assess the potential of impact analysis to retrieve AC implant insertion conditions. A dynamic two-dimensional axisymmetric model was developed to simulate the impaction of the AC implant into bone tissue assuming friction at the bone–implant interface and large deformations. Different values of interference fit (from 0.5 to 2 mm) and impact velocities (from 1 to 2 m.s^?1) were considered. For each configuration, the variation of the force applied between the hammer and the ancillary was analyzed and an indicator I was determined based on the impact momentum of the signal. The simulated results are compared to the experiments. The value of the polar gap decreases with the impact velocity and increases with the interference fit. The bone–implant contact area was significantly correlated with the resonance frequency (R ² = 0.94) and the indicator (R ² = 0.95). The results show the potential of impact analyses to retrieve the bone–implant contact properties.     

From the Cover: Mitochondrial DNA from the eradicated European Plasmodium vivax and P. falciparum from 70-year-old slides from the Ebro Delta in Spain

Phylogenetic analysis of Plasmodium parasites has indicated that their modern-day distribution is a result of a series of human-mediated dispersals involving transport between Africa, Europe, America, and Asia. A major outstanding question is the phylogenetic affinity of the malaria causing parasites Plasmodium vivax and falciparum in historic southern Europe—where it was endemic until the mid-20th century, after which it was eradicated across the region. Resolving the identity of these parasites will be critical for answering several hypotheses on the malaria dispersal. Recently, a set of slides with blood stains of malaria-affected people from the Ebro Delta (Spain), dated between 1942 and 1944, have been found in a local medical collection. We extracted DNA from three slides, two of them stained with Giemsa (on which Plasmodium parasites could still be seen under the microscope) and another one consisting of dried blood spots. We generated the data using Illumina sequencing after using several strategies aimed at increasing the Plasmodium DNA yield: depletion of the human genomic (g)DNA content through hybridization with human gDNA baits, and capture-enrichment using gDNA derived from P. falciparum. Plasmodium mitochondrial genome sequences were subsequently reconstructed from the resulting data. Phylogenetic analysis of the eradicated European P. vivax mtDNA genome indicates that the European isolate is closely related to the most common present-day American haplotype and likely entered the American continent post-Columbian contact. Furthermore, the European P. falciparum mtDNA indicates a link with current Indian strains that is in agreement with historical accounts.The genus Plasmodium contains two of the most significant human pathogenic organisms. One, Plasmodium vivax, is the most widely distributed human malaria parasite outside of Africa, with a range that extends well into temperate zones (1), whereas the other, Plasmodium falciparum, is the predominant malaria parasite of humans in subsaharan Africa and the one that causes >90% malarial deaths (2).Although an increasing number of studies have attempted to investigate the present-day distribution of Plasmodium parasites using DNA sourced from modern isolates of the pathogens, their origin and dispersal around the planet remain controversial. For example, the current global distribution of P. vivax includes Asia, the Middle East, South and Central America, and parts of Africa (3) and has likely resulted from complex dispersals involving intercontinental human population movements (4, 5). Although an African origin is likely (6), the current strains from this continent show little genetic polymorphism compared with the rest of the world (4), a fact that has been related to the emergence of Duffy-negative blood types—resistant to P. vivax—in human populations from this continent (7). Alternatively, it has been suggested that modern African parasites, at least in the Horn of Africa and Madagascar, could have been reintroduced via the import of East Asian/Indian P. vivax to the coastal areas of East Africa by early sea-going traders and that this could explain their lack of diversity (4). Intriguingly, the diversity of the American strains is comparable to those found in Oceania and Asia (8), raising questions regarding the origin of these strains. Some of the American strains are thought to have been brought there from Europe by Spanish sailors and colonists in the last few centuries (4, 9). An alternative possibility would imply a pre-Columbian entrance through the Bering Straits during the initial peopling of the Americas, although this seems unlikely due to the climatic conditions of this passage (9) and the long Beringian standstill that likely lasted up to several thousands of years (10). However, the existence of divergent mitochondrial lineages in the Americas seems to rule out the possibility of a single, recent introduction of P. vivax from Europe into this continent (8). At the nuclear level, the American isolates show geographic differentiation but also a common clustering regarding the Old World populations (5).With regard to the evolutionary history of P. falciparum, genetic analyses of Laveriana parasite species found in African chimpanzees and gorillas, considered to be precursors of the human parasites, prove an African origin (11), but the time by which the parasite dispersed out of Africa remains controversial. Although some suggest that the pathogen followed the original Homo sapiens dispersals around 60,000 y ago (12), others support a recent expansion within the last 5,000–10,000 y associated to the advent of agriculture (2). The recent analysis of 44 Indian field isolates showed, however, a higher than expected diversity and suggested that the Indian strains are also part of the ancestral distribution range of P. falciparum (13). Historical accounts seem to indicate that malaria spread from India into the Mediterranean at the time of Classical Greece; therefore, the now extinct European P. falciparum could be genetically related to some of these Indian parasites.The current controversies on the recent evolutionary history of P. vivax and P. falciparum partly relate to the lack of genetic evidence from the European parasite that was eradicated more than half century ago. In Spain, malaria had remained endemic until the early 20th century, in particular in Andalucia, Extremadura, and Ebro delta regions; it was declared oficially eradicated in 1964 (14). P. vivax and P. falciparum have been transmitted in southern Spain by two former malaria vectors: Anopheles atroparvus and Anopheles labranchiae. Both were present in the country but whereas An. atroparvus is still widely spread, An. labranchiae has not been found since the middle of the last century (15). An. atroparvus from different geographic origins are infected in laboratory with different world strains of P. vivax, whereas it is very difficult to do the same in the case of P. falciparum (16). Thus, the lack of genetic evidence of the former Plasmodium European parasites also hampers our understanding of their biology.To clarify the phylogenetic position of the extinct European Plasmodium strains, we report here the retrieval of the European P. vivax and P. falciparum genetic data from the analysis of three recently discovered old slides with blood drops from malaria-infected people living at the Ebro Delta in Spain in the first half of the 20th century that corresponds to local epidemics (Fig. 1).Open in a separate windowFig. 1.(A) Two of the Giemsa-stained slides analyzed in this study, labeled CM and CA (inferior stain). (B) Visualization of some Plasmodium parasites (arrows) in the CM slide under the microscope (400×).