Element distribution in visual system, the optic chiasma, lateral geniculate body, and superior colliculus

Preparation, characterisation, pharmacokinetics and distribution of esculin microspheres administered via intravitreal injection into rabbit brain

This study explored the distribution of esculin microspheres in rabbit brain tissue following intravitreal injection and investigated the possibility of direct entry of the drug into the brain through the eye, to develop a formulation with enhanced therapeutic efficacy against Parkinson's disease.Chitosan microspheres of esculin were prepared via an emulsification cross-linking method and their characteristics were evaluated, including angle of repose, bulk density, and swelling ratio. Furthermore, the pharmacokinetic parameters and brain tissue distribution in rabbits were compared among groups administered esculin eye drops, intravitreal esculin solution, and intravitreal esculin microspheres, to determine whether esculin could enter the brain through an ocular route.The results showed that the prepared esculin microspheres were spherical and had good fluidity. Notably, intravitreal administration enhanced the area under the curve (AUC) of esculin in the thalamus. Delivery through microspheres prolonged the drug retention time in both rabbit plasma and brain tissues, as well as the brain-targeting efficiency of esculin.The collective findings indicated that there may be a direct eye-brain pathway facilitating enter of esculin microspheres into brain tissue after intravitreal injection, supporting the utility of intravitreal esculin microspheres as an effective therapeutic formulation for Parkinson's disease, a long-term chronic condition.

Visual, auditive and somatosensory pathways alterations in geriatric rhesus monkeys (Macaca mulatta)

BACKGROUND

Synapses loss during aging is associated to neurophysiologic alterations that impair organism's health span, thus making the study and prevention of sensory decline relevant for healthy aging and welfare. Therefore the aim of this study was to obtain normative data related to the electrophysiological responses of the different neurosensory components in the visual, auditory and somatosensory pathways in healthy geriatric rhesus monkeys in captivity.

METHODS

Twenty-four rhesus monkeys were divided in two groups: (i) Geriatric monkeys, 20-30 years of age, and (ii) Young monkeys, 7 years of age. Evoked potentials were obtained from the visual, auditory and somatosensory pathways.

RESULTS

Regardless the sensory pathways evaluated, a significant delay in nerve conduction was observed in the geriatric group in comparison to the young group.

CONCLUSIONS

Evoked potentials allowed identifying changes generated during aging in rhesus monkeys and normative data for this species were obtained.

Iron in Multiple Sclerosis and Its Noninvasive Imaging with Quantitative Susceptibility Mapping

Iron is considered to play a key role in the development and progression of Multiple Sclerosis (MS). In particular, iron that accumulates in myeloid cells after the blood-brain barrier (BBB) seals may contribute to chronic inflammation, oxidative stress and eventually neurodegeneration. Magnetic resonance imaging (MRI) is a well-established tool for the non-invasive study of MS. In recent years, an advanced MRI method, quantitative susceptibility mapping (QSM), has made it possible to study brain iron through in vivo imaging. Moreover, immunohistochemical investigations have helped defining the lesional and cellular distribution of iron in MS brain tissue. Imaging studies in MS patients and of brain tissue combined with histological studies have provided important insights into the role of iron in inflammation and neurodegeneration in MS.

Iron in Multiple Sclerosis and Its Noninvasive Imaging with Quantitative Susceptibility Mapping

Iron is considered to play a key role in the development and progression of Multiple Sclerosis (MS). In particular, iron that accumulates in myeloid cells after the blood-brain barrier (BBB) seals may contribute to chronic inflammation, oxidative stress and eventually neurodegeneration. Magnetic resonance imaging (MRI) is a well-established tool for the non-invasive study of MS. In recent years, an advanced MRI method, quantitative susceptibility mapping (QSM), has made it possible to study brain iron through in vivo imaging. Moreover, immunohistochemical investigations have helped defining the lesional and cellular distribution of iron in MS brain tissue. Imaging studies in MS patients and of brain tissue combined with histological studies have provided important insights into the role of iron in inflammation and neurodegeneration in MS.

Age-related differences and relationships between elements in human amygdala and other limbic system or basal ganglia

To elucidate the compositional changes of the amygdala with aging, the authors investigated age-related differences of elements in human amygdalae. In addition, the relationships between the amygdala and other brain regions were investigated from a viewpoint of elements. After ordinary dissections at Nara Medical University were finished, the amygdalae were removed from the cerebra of the subjects who consisted of 22 men and 23 women, ranging in age from 70 to 101 years. In addition, the hippocampus, dentate gyrus, mammillary body of the limbic system and the caudate nucleus, putamen, and globus pallidus of the basal ganglia were also removed from the identical cerebra. After the brain samples were incinerated with nitric acid and perchloric acid, the element contents were determined by inductively coupled plasma-atomic emission spectrometry. It was found that both the Ca and Mg contents increased significantly in the amygdalae with aging, but the other five element contents (P, S, Zn, Fe, and Na) did not change significantly in the amygdalae with aging. Regarding the relationships among elements, very significant or significant direct correlations were found among the Ca, P, and Mg contents in the amygdalae. To explore the relationships between the amygdala and either other limbic system or basal ganglia, the correlations between seven elements of the amygdala and hippocampus, dentate gyrus, or mammillary body, and between those of the amygdala and caudate nucleus, putamen, or globus pallidus which derived from the identical cerebra, were analyzed with Pearson's correlation. It was found that regarding the four elements of Ca, P, Mg, and Fe, a close relationship existed between the amygdala and hippocampus, globus pallidus, or mammillary body.

Mineral composition of and the relationships between them of human basal ganglia in very old age

Trace elements and the relationships among them were investigated by direct chemical analysis in three basal ganglia regions in very old age individuals and age- and gender-related differences were assessed. After ordinary dissections at Nara Medical University were finished, the caudate nucleus, putamen, and globus pallidus belonging to the basal ganglia were removed from the identical cerebra of the subjects who consisted of 22 men and 23 women, ranging in age from 70 to 101 years (average age = 83.3 ± 7.5 years). After incineration with nitric acid and perchloric acid, the element contents were determined by inductively coupled plasma-atomic emission spectrometry. It was found that the Ca, P, and Mg contents increased significantly in the putamen with aging and the Mg content increased significantly in the globus pallidus with aging, but no elements increased significantly in the caudate nucleus with aging. Regarding the relationships among elements in the basal ganglia, extremely significant direct correlations were found among the Ca, P, and Mg contents in the putamen. These results suggested that slight calcification occurred in the putamen in very old age. With regard to seven elements of Ca, P, S, Mg, Zn, Fe, and Na, it was examined whether there were significant correlations among the caudate nucleus, putamen, and globus pallidus. It was found that there were extremely significant direct correlations among all of the three basal ganglia in the P content. Likewise, with regard to the Fe content, there were extremely or very significant direct correlations among all of the three basal ganglia. Regarding the gender difference in elements, it was found that the Ca content of the caudate nucleus was significantly higher in women than in men.