Intramolecular Hydrogen Bonding Effect on the Electron-Transfer Thermodynamics of a Series of o-Nitrobenzyl Alcohol Derivatives.

From thermoelectrochemical experiments and electronic structure calculations of a series of nitrobenzyl alcohol derivatives, the effect of intramolecular hydrogen bonding (IHB) on the electron transfer thermodynamics is discussed on a molecular basis. A linear correlation between formal reduction potential (E1/2) values and temperature was obtained for the temperature range from 300 to 350 K. Estimated electron transfer entropy values (ΔS)─determined from this dependence─and the enthalpy (ΔΔH) changes relative to o-nitrobenzyl alcohol confirmed that the effect of the formation of IHB proved to be decisive in the charge-transfer thermodynamics. The possibility of intermolecular hydrogen bonding is further discussed upon comparing thermodynamic data among three different solvents.

Long-term exposure to GDNF induces dephosphorylation of Ret, AKT, and ERK1/2, and is ineffective at protecting midbrain dopaminergic neurons in cellular models of Parkinson's disease.

Glial cell line-derived neurotrophic factor (GDNF) promotes differentiation, proliferation, and survival in different cell types, including dopaminergic neurons. Thus, GDNF has been proposed as a promising neuroprotective therapy in Parkinson's disease. Although findings from cellular and animal models of Parkinson's disease were encouraging, results emerging from clinical trials were not as good as expected, probably due to the inappropriate administration protocols. Despite the growing information on GDNF action mechanisms, many aspects of its pharmacological effects are still unclear and data from different studies are still contradictory. Considering that GDNF action mechanisms are mediated by its receptor tyrosine kinase Ret, which activates PI3K/AKT and MAPK/ERK signaling pathways, we aimed to investigate Ret activation and its effect over both signaling pathways in midbrain cell cultures treated with GDNF at different doses (0.3, 1, and 10 ng/ml) and times (15 min, 24 h, 24 h (7 days), and 7 continuous days). The results showed that short-term or acute (15 min, 24 h, and 24 h (7 days)) GDNF treatment in rat midbrain neurons increases Tyrosine hydroxylase (TH) expression and the phosphorylation levels of Ret (Tyr 1062), AKT (Ser 473), ERK1/2 (Thr202/Tyr204), S6 (Ser 235/236), and GSK3-ß (Ser 9). However, the phosphorylation level of these kinases, TH expression, and dopamine uptake, decreased below basal levels after long-term or prolonged treatment with 1 and 10 ng/ml GDNF (7 continuous days). Our data suggest that long-term GDNF treatment inactivates the receptor by an unknown mechanism, affecting its neuroprotective capacity against degeneration caused by 6-OHDA or rotenone, while short-term exposure to GDNF promoted dopaminergic cell survival. These findings highlight the need to find new and more effective long-acting therapeutic approaches for disorders in which GDNF plays a beneficial role, including Parkinson's disease. In this regard, it is necessary to propose new GDNF treatment guidelines to regulate and control its long-term expression levels and optimize the clinical use of this trophic factor in patients with Parkinson's disease.

Production and physicochemical characterization of chitosan for the harvesting of wild microalgae consortia.

The use of chitosan to harvest microalgae is a strategic step that seeks to reach an economically competitive price to recover lipids, proteins, and pigments. The aim of the present work was to design low-molecular-weight chitosan from shrimp shells and its physicochemical characterization, to be used for the harvesting of wild microalgae consortia. The chitosan was obtained by chemical deacetylation of shrimp shells, and physicochemical characterization was made using the instrumental methods DSC, TGA, X-ray, FTIR, and SEM. The harvesting of wild microalgae consortia was performed by the jar test method. The obtained chitosan had a low molecular weight (169 KDa), a deacetylation degree of 83 %, a decomposition temperature (TD) of 280 °C, and a crystallinity of 38.2 %. The microalgae genera found in the consortium were Scenedesmus sp., Chlorella sp., Schroderia sp., and Chlamydomonas sp. The microalgae removal efficiency of the chitosan was 99.2 % with 20 mg L-1.

Reflejo pudendo profundo / Deep pudendal reflex

Se estudiaron 32 mujeres voluntarias normales, con edades que oscilaron entre los 20 y 68 años. Se les provocó el Reflejo Pudendo Profundo (RPP) mediante un electrodo de superfície especial que tiene la ventaja de servir para el registro del esfínter anal y también para el estímulo del nervio pudendo. Se describe la técnica para la obtención del reflejo tras la estimulación de dicho nervio a nivel de la espina isquiática. Se obtuvo una latencia media de 36,18 mseg ñ 4,29 con una amplitud media de 306,11 uv ñ DS 227,15. Al efectuar el RPP se realiza un reflejo pudendo-anal que difere del clássico reflejo bulbocavernoso en cuanto a la localización del estímulo, de las latencias, y también en su vía aferente aunque comparten un trayecto común en parte del mismo

Reflejo pudendo profundo / Deep pudendal reflex

Se estudiaron 32 mujeres voluntarias normales, con edades que oscilaron entre los 20 y 68 años. Se les provocó el Reflejo Pudendo Profundo (RPP) mediante un electrodo de superfície especial que tiene la ventaja de servir para el registro del esfínter anal y también para el estímulo del nervio pudendo. Se describe la técnica para la obtención del reflejo tras la estimulación de dicho nervio a nivel de la espina isquiática. Se obtuvo una latencia media de 36,18 mseg ñ 4,29 con una amplitud media de 306,11 uv ñ DS 227,15. Al efectuar el RPP se realiza un reflejo pudendo-anal que difere del clássico reflejo bulbocavernoso en cuanto a la localización del estímulo, de las latencias, y también en su vía aferente aunque comparten un trayecto común en parte del mismo (AU)

Pudendal reflexes in women with pelvic floor disorders.

The objective of this work was to study two pudendal anal reflexes: Deep Pudendal Reflex (DPR) and classical Bulbocavernosus Reflex (BCR) in women with primary and recurrent genital prolapse to obtain support to the hypothesis of pelvic nerve damage in patients with pelvic floor disorders. 124 women were studied: 68 were normal; 38 with genital prolapse (GP); and 18 with recurrent GP. Clinical and electrophysiological studies were carried out. Delayed reflex responses were found in 44/56 of patients (79%). [27/38 in genital prolapse group (71%); 17/18 in recurrent GP group (94%)]. The evaluation of pelvic floor reflex responses are tests to be taken into account in the diagnosis and management of pelvic floor disorders.

[Deep pudendal reflex]. / Reflejo pudendo profundo.

32 healthy women ranging from 20 to 68 years (51.84 +/- 10.36) were tested for Deep Pudendal Reflex (DPR). Dantec 13L40 (St. Mark's) superficial electrodes were used to pick up the responses of the external anal sphincter. These devices consist of a bipolar stimulating electrode mounted on the tip of the gloved index finger which is inserted into the rectum; 3 cm proximally at the base of the finger are recording electrodes which pick up the contraction response of the anal sphincter. To obtain the DPR the ischial spine is localized on transrectal examination and electrical stimuli given at that side, applying square stimulus of 0.2 ms duration and 0.5 Hz frequency. This stimulates the pudendal nerve as it leaves the pelvis through the greater sciatic notch, before it branches into the inferior rectal (to the anal sphincter) and perineal nerve (to the periurethral striated muscle). The conduction time was measured as the latency from the time of stimulation of the starting point of the reflex response curves. The shortest latency of various responses was accepted and measured in milliseconds (ms). The amplitudes of the responses were measured in microvolts (uv). We obtained reproducible DPR in all subjects. Mean latency was 36.18 +/- 4.29 ms; mean amplitude was 337.50 +/- 218.49 uv (Fig. 1, Table 2). DPR is a pudendal-anal reflex like the bulbo-cavernous reflex, but differs in latency, stimulation localization and afferent limb although both follow a common final afferent pathway.

Reflejo pudendo profundo. / [Deep pudendal reflex]

32 healthy women ranging from 20 to 68 years (51.84 +/- 10.36) were tested for Deep Pudendal Reflex (DPR). Dantec 13L40 (St. Marks) superficial electrodes were used to pick up the responses of the external anal sphincter. These devices consist of a bipolar stimulating electrode mounted on the tip of the gloved index finger which is inserted into the rectum; 3 cm proximally at the base of the finger are recording electrodes which pick up the contraction response of the anal sphincter. To obtain the DPR the ischial spine is localized on transrectal examination and electrical stimuli given at that side, applying square stimulus of 0.2 ms duration and 0.5 Hz frequency. This stimulates the pudendal nerve as it leaves the pelvis through the greater sciatic notch, before it branches into the inferior rectal (to the anal sphincter) and perineal nerve (to the periurethral striated muscle). The conduction time was measured as the latency from the time of stimulation of the starting point of the reflex response curves. The shortest latency of various responses was accepted and measured in milliseconds (ms). The amplitudes of the responses were measured in microvolts (uv). We obtained reproducible DPR in all subjects. Mean latency was 36.18 +/- 4.29 ms; mean amplitude was 337.50 +/- 218.49 uv (Fig. 1, Table 2). DPR is a pudendal-anal reflex like the bulbo-cavernous reflex, but differs in latency, stimulation localization and afferent limb although both follow a common final afferent pathway.