Cover Image,Volume 20, Issue 4

The cover image, by Inmaculada Ruz‐Maldonado et al., is based on the Original Article LH‐21 and abnormal cannabidiol improve β‐cell function in isolated human and mouse islets through GPR55‐dependent and ‐independent signalling, DOI: 10.1111/dom.13180 .

     

Modeling Chagas Disease at Population Level to Explain Venezuela's Real Data

Objectives

In this paper we present an age-structured epidemiological model for Chagas disease. This model includes the interactions between human and vector populations that transmit Chagas disease.

Methods

The human population is divided into age groups since the proportion of infected individuals in this population changes with age as shown by real prevalence data. Moreover, the age-structured model allows more accurate information regarding the prevalence, which can help to design more specific control programs. We apply this proposed model to data from the country of Venezuela for two periods, 1961–1971, and 1961–1991 taking into account real demographic data for these periods.

Results

Numerical computer simulations are presented to show the suitability of the age-structured model to explain the real data regarding prevalence of Chagas disease in each of the age groups. In addition, a numerical simulation varying the death rate of the vector is done to illustrate prevention and control strategies against Chagas disease.

Conclusion

The proposed model can be used to determine the effect of control strategies in different age groups.     

Phytochemical screening and effects on cell-mediated immune response of Pleurotus fruiting bodies powder

This study examined the phytochemical profile and the effects of Pleurotus fruiting bodies powder on cell-mediated immune response in both in vivo and in vitro assays. Although carbohydrates (55%, w/w) appear to be the most important immunomodulatory compound, secondary metabolites (terpenoids, phenols and flavonoids) would also enhance immunity. Pleurotus powder was administered orally during 7 days to Balb/c mice (1000 mg/kg) and cyclophosphamide (CY; 100 mg/kg) was inoculated intraperitoneally at the beginning of the experiment. The delayed-type hypersensitivity reaction measured at 48 and 72 h after antigen challenge was similar to that of control mice and it was associated with an increase in the mass index of popliteal lymph nodes (p< 0.05). An in vitro lymphoproliferative-stimulating response was also demonstrated with aqueous and ethanolic extracts obtained from Pleurotus powder. These effects suggest that Pleurotus supplement could potentiate the cellular immune response and should be promising for further immunotherapy studies.     

Testing the inhibitory cascade model in the Middle Pleistocene Sima de los Huesos (Sierra de Atapuerca,Spain) hominin sample

The Middle Pleistocene Sima de los Huesos (SH) site has yielded more than 7.500 human fossil remains belonging to a minimum of 29 individuals. Most of these individuals preserve either the complete mandibular molar series or at least the first (M₁) and second (M₂) molars. The inhibitory cascade mathematical model was proposed by Kavanagh et al. (Nature, 449, 427–433 [2007]) after their experimental studies on the dental development of murine rodent species. The activator–inhibitor mechanism of this model has shown its ability for predicting evolutionary size patterns of mammalian teeth, including hominins. The main aim of this study is to test whether the size molar patterns observed in the SH hominins fit the inhibitory cascade model. With this purpose, we have measured the crown area of all SH molars in photographs, using a planimeter and following techniques used and well contrasted in previous works. Following one of the premises of the inhibitory cascade model, we expect that the central tooth (M₂ in our case) of a triplet would have the average size of the two outer teeth. The absolute difference between the observed and the expected values for the M₂s ranges from 0.23 to 8.46 mm² in the SH sample. In terms of percentage, the difference ranges between 0.25% and 10.34%, although in most cases, it is below 5%. The plot of the estimated M₃/M₁ and M₂/M₁ size ratios obtained in the SH hominins occupies a small area of the theoretical developmental morphospace obtained for rodent species. In addition, the majority of the values are placed near the theoretical line which defines the relationship predicted by the inhibitory cascade model in these mammals. The values of the slope and intercept of the reduced major regression obtained for the SH individuals do not differ significantly from those obtained for rodent species, thus confirming that the size of the molars of the SH hominins fits the inhibitory cascade model. We discuss these results in terms of dental development. Despite the promising results in the SH sample, we draw the attention to the fact that most Early Pleistocene Homo specimens exhibit a pattern (M₁ < M₂ > M₃), which is outside the expected theoretical morphospace predicted by the inhibitory cascade model. The shift from the M1 < M2 < M3 size relationship observed in early hominins (including H. habilis) to the M1 > M2 > M3 size relationship, which is predominant in modern humans, includes sequences that depart from predictions of the inhibitory cascade model. Additional studies are required to understand these deviations.     

Visual hallucinations of autobiographic memory and asomatognosia: a case of epilepsy due to brain cysticercosis

The current study describes the case of a woman with symptomatic epilepsy due to brain cysticercosis acquired during childhood. During her adolescence, she developed seizures characterized by metamorphopsia, hallucinations of autobiographic memory and, finally, asomatognosia. Magnetic brain imaging showed a calcified lesion in the right occipitotemporal cortex, and positron emission tomography imaging confirmed the presence of interictal hypometabolism in two regions: the right parietal cortex and the right lateral and posterior temporal cortex. We discuss the link between these brain areas and the symptoms described under the concepts of epileptogenic lesion, epileptogenic zone, functional deficit zone, and symptomatogenic zone.     

A functional magnetic resonance imaging study of visuomotor processing in a virtual reality‐based paradigm: Rehabilitation Gaming System

The Rehabilitation Gaming System (RGS) has been designed as a flexible, virtual‐reality (VR)‐based device for rehabilitation of neurological patients. Recently, training of visuomotor processing with the RGS was shown to effectively improve arm function in acute and chronic stroke patients. It is assumed that the VR‐based training protocol related to RGS creates conditions that aid recovery by virtue of the human mirror neuron system. Here, we provide evidence for this assumption by identifying the brain areas involved in controlling the catching of approaching colored balls in the virtual environment of the RGS. We used functional magnetic resonance imaging of 18 right‐handed healthy subjects (24 ± 3 years) in both active and imagination conditions. We observed that the imagery of target catching was related to activation of frontal, parietal, temporal, cingulate and cerebellar regions. We interpret these activations in relation to object processing, attention, mirror mechanisms, and motor intention. Active catching followed an anticipatory mode, and resulted in significantly less activity in the motor control areas. Our results provide preliminary support for the hypothesis underlying RGS that this novel neurorehabilitation approach engages human mirror mechanisms that can be employed for visuomotor training.