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[Purpose]: To define the characteristics and time course of the morphologic and functional changes experienced by corneal sensory nerves after photorefractive keratectomy (PRK)., [Methods]: Unilateral corneal excimer laser photoablation was performed in 54 anesthetized 3- to 6-month-old mice; 11 naïve animals served as control. Mice were killed 0, 3, 7, 15, and 30 days after PRK. Excised eyes were placed in a recording chamber superfused at 34°C. Electrical nerve impulse activity of single sensory terminals was recorded with a micropipette applied onto the corneal surface. Spontaneous and stimulus-evoked (cold, heat, mechanical, and chemical stimuli) nerve terminal impulse (NTI) activity was analyzed. Corneas were fixed and stained with anti-β-Tubulin III antibody to measure nerve density and number of epithelial nerve penetration points of regenerating subbasal leashes., [Results]: Nerve fibers and NTI activity were absent in the injured area between 0 and 7 days after PRK, when sparse regenerating nerve sprouts appear. On day 15, subbasal nerve density reached half the control value and abnormally responding cold-sensitive terminals were recorded inside the lesion. Thirty days after PRK, nerve density was almost restored, active cold thermoreceptors were abundant, and polymodal nociceptor activity first reappeared., [Conclusions]: Morphologic regeneration of subbasal corneal nerves started shortly after PRK ablation and was substantially completed 30 days later. Functional recovery appears faster in cold terminals than polymodal terminals, possibly reflecting an incomplete damage of the more extensively branched cold-sensitive axon terminals. Evolution of postsurgical discomfort sensations quality may be associated with the variable regeneration pattern of each fiber type., Supported by FC-15-GRUPIN14-141 (Consejería de Economía y Empleo, Asturias, Spain); SAF2014-54518-C3-1-R, SAF2014-54518-C3-2-R, SAF2017-83674-C2-1-R, and SAF2017-83674-C2-2-R (Ministerio de Economía, Industria y Competitividad, Spain, and European Regional Development Funds, European Union), and the Spanish “Severo Ochoa” Program for Centers of Excellence in R&D (SEV-2013-0317). Funding from Fundación Ramón Areces and Caja Rural de Asturias, Spain, and European Commission H2020 GA No. 667400 are also acknowledged.

This is an open access article under the terms of the Creative Commons Attribution-Non Commercial-No Derivs License., Morphological and functional alterations of peripheral somatosensory neurons during the aging process lead to a decline of somatosensory perception. Here, we analyze the changes occurring with aging in trigeminal ganglion (TG), TRPM8-expressing cold thermoreceptor neurons innervating the mouse cornea, which participate in the regulation of basal tearing and blinking and have been implicated in the pathogenesis of dry eye disease (DED). TG cell bodies and axonal branches were examined in a mouse line (TRPM8BAC-EYFP) expressing a fluorescent reporter. In 3 months old animals, about 50% of TG cold thermoreceptor neurons were intensely fluorescent, likely providing strongly fluorescent axons and complex corneal nerve terminals with ongoing activity at 34°C and low-threshold, robust responses to cooling. The remaining TRPM8+ corneal axons were weakly fluorescent with nonbeaded axons, sparsely ramified nerve terminals, and exhibited a low-firing rate at 34°C, responding moderately to cooling pulses as do weakly fluorescent TG neurons. In aged (24 months) mice, the number of weakly fluorescent TG neurons was strikingly high while the morphology of TRPM8+ corneal axons changed drastically; 89% were weakly fluorescent, unbranched, and often ending in the basal epithelium. Functionally, 72.5% of aged cold terminals responded as those of young animals, but 27.5% exhibited very low-background activity and abnormal responsiveness to cooling pulses. These morpho-functional changes develop in parallel with an enhancement of tear's basal flow and osmolarity, suggesting that the aberrant sensory inflow to the brain from impaired peripheral cold thermoreceptors contributes to age-induced abnormal tearing and to the high incidence of DED in elderly people., This work was supported by grants FC-15-GRUPIN14–141 (Consejería de Economía y Empleo, Asturias, Spain), Fundación Ramón Areces, Caja Rural de Asturias, SAF2014–54518-C3-2-R, SAF2014–54518-C3-1-R, SAF2017–83674-C2-2-R, SAF2017–83674-C2-1-R, and SAF2016–77233-R (Ministerio de Economía, Industria y Competitividad, Spain and European Regional Development Funds, European Union), and “Severo Ochoa” Program for Centers of Excellence in R&D (SEV-2013-0317).

A more open and competitive dairy market has encouraged certain dairy farms to adopt value-adding strategies in order to achieve a higher profitability, which may be important for farms’ survival. This paper investigated the role of some product characteristics in the profitability of value-added products in these farms. For this purpose, we used a unique database of 265 different products commercialized by 49 Spanish dairy farms that offers information on nine attributes of each product. Using hedonic models as a baseline, we examined the influence of these attributes on the margin per liter (ML) of the products. The results of the regression indicated that cheese and yogurt generated 0.688 and 1.518 € more of margin per liter than liquid milk. Similarly, we found a set of attributes that have a positive influence on ML, including possession of a certificate of protected designation of origin (PDO), the milk-type composition (proportion of sheep milk), a longer expiration period, and involvement in direct marketing strategies (DMS). However, other recognized attributes such as organic labeling, maturation period, size of the sales unit and returnable packaging did not have a significant influence on ML. Our findings also showed that firms producing more elaborated products as cheese and yogurt need a lower percentage of their production to cover the fixed costs associated to transformation and commercialization. Overall, our results revealed that the elaboration of value-added dairy products improves the profitability of dairy farms.

[Purpose]: To define the firing properties of sensory nerve terminals innervating the adult mouse cornea in response to external stimuli of differing modality., [Methods]: Extracellular electrical activity of single corneal sensory nerve terminals was recorded in excised eyes of C57BL/6J mice. Eyes were placed in a recording chamber and were continuously superfused with warm saline solution. Nerve terminal impulse (NTI) activity was recorded by means of a glass pipette (tip ∼ 50 μm), applied on the corneal surface. Nerve terminal impulse discharges were stored in a computer for offline analysis., [Results]: Three functionally distinct populations of nerve terminals were identified in the mouse cornea. Pure mechanonociceptor terminals (9.5%) responded phasically and only to mechanical stimuli. Polymodal nociceptor terminals (41.1%) were tonically activated by heat and hyperosmolal solutions (850 mOsm·kg−1), mechanical force, and/or TRPV1 and TRPA1 agonists (capsaicin and allyl isothiocyanate [AITC], respectively). Cold-sensitive terminals (49.4%) responded to cooling. Approximately two-thirds of them fired continuously at 34°C and responded vigorously to small temperature reductions, being classified as high-background activity, low-threshold (HB-LT) cold thermoreceptor terminals. The remaining one-third exhibited very low ongoing activity at 34°C and responded weakly to intense cooling, being named low-background activity, high-threshold (LB-HT) cold thermoreceptor terminals., [Conclusions]: The mouse cornea is innervated by trigeminal ganglion (TG) neurons that respond to the same stimulus modalities as corneal receptors of other mammalian species. Mechano- and polymodal endings underlie detection of mechanical and chemical noxious stimuli while HB-LT and LB-HT cold thermoreceptors appear to be responsible for basal and irritation-evoked tearing and blinking, respectively., Supported by Grants FC-15-GRUPIN14-141 from the Consejería de Economía y Empleo del Gobierno del Principado de Asturias, Spain, cosponsored with FEDER funds from the European Union and the Fundación Ramón Areces, Caja Rural de Asturias, and Ministerio de Economía y Competitividad of Spain and FEDER (SAF2014-54518-C3-1-R and SAF2014-54518-C3-2-R). C.B. acknowledges financial support from the Spanish State Research Agency, through the “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV-2013-0317).

La utilización de bacteriófagos, virus específicos de bacterias, podría ser la solución frente a las bacterias causantes de mamitis multirresistentes a los antibióticos, Proyecto de investigación financiado por el Plan Regional de Investigación de Asturias y cofinanciado por la Caja Rural de Asturias