Effects of epidural compression on stellate neurons and thalamocortical afferent fibers in the rat primary somatosensory cortex.

A number of neurological disorders such as epidural hematoma can cause compression of cerebral cortex. We here tested the hypothesis that sustained compression of primary somatosensory cortex may affect stellate neurons and thalamocortical afferent (TCA) fibers. A rat model with barrel cortex subjected to bead epidural compression was used. Golgi-Cox staining analyses showed the shrinkage of dendritic arbors and the stripping of dendritic spines of stellate neurons for at least 3 months post-lesion. Anterograde tracing analyses exhibited a progressive decline of TCA fiber density in barrel field for 6 months post-lesion. Due to the abrupt decrease of TCA fiber density at 3 days after compression, we further used electron microscopy to investigate the ultrastructure of TCA fibers at this time. Some TCA fiber terminal profiles with dissolved or darkened mitochondria and fewer synaptic vesicles were distorted and broken. Furthermore, the disruption of mitochondria and myelin sheath was observed in some myelinated TCA fibers. In addition, expressions of oxidative markers 3-nitrotyrosine and 4-hydroxynonenal were elevated in barrel field post-lesion. Treatment of antioxidant ascorbic acid or apocynin was able to reverse the increase of oxidative stress and the decline of TCA fiber density, rather than the shrinkage of dendrites and the stripping of dendritic spines of stellate neurons post-lesion. Together, these results indicate that sustained epidural compression of primary somatosensory cortex affects the TCA fibers and the dendrites of stellate neurons for a prolonged period. In addition, oxidative stress is responsible for the reduction of TCA fiber density in barrels rather than the shrinkage of dendrites and the stripping of dendritic spines of stellate neurons.

The Tzu Chi Silent Mentor Program: Application of Buddhist Ethics to Teach Student Physicians Empathy, Compassion, and Self-Sacrifice.

The Buddhist Tzu Chi Silent Mentor Program promotes the donation of one's body to science as a selfless act by appealing to the Buddhist ethics of compassion and self-sacrifice. Together, faculty, families, and donors help medical students to learn the technical, spiritual, emotional, and psychological aspects of medicine. Students assigned to each "Silent Mentor" visit the family to learn about the donor's life. They see photos and hear family members' stories. Afterwards, students write a brief biography of the donor which is posted on the program website, in the medical school, and on the dissection table. In this paper, we: (1) summarize the Silent Mentor Program; (2) describe findings from an assessment of medical students who recently completed a new version of the program in Malaysia; and (3) explore how healthcare settings could benefit from this innovative program.

Exogenous dehydroisoandrosterone sulfate reverses the dendritic changes of the central neurons in aging male rats.

Sex hormones are known to help maintaining the cognitive ability in male and female rats. Hypogonadism results in the reduction of the dendritic spines of central neurons which is believed to undermine memory and cognition and cause fatigue and poor concentration. In our previous studies, we have reported age-related regression in dendrite arbors along with loss of dendritic spines in the primary somatosensory cortical neurons in female rats. Furthermore, castration caused a reduction of dendritic spines in adult male rats. In light of this, it was surmised that dendritic structures might change in normal aging male rats with advancing age. Recently, dehydroepiandrosterone sulfate (DHEAS) has been reported to have memory-enhancing properties in aged rodents. In this study, normal aging male rats, with a reduced plasma testosterone level of 75-80%, were used to explore the changes in behavioral performance of neuronal dendritic arbor and spine density. Aging rats performed poorer in spatial learning memory (Morris water maze). Concomitantly, these rats showed regressed dendritic arbors and spine loss on the primary somatosensory cortical and hippocampal CA1 pyramidal neurons. Exogenous DHEAS and testosterone treatment reversed the behavioral deficits and partially restored the spine loss of cortical neurons in aging male rats but had no effects on the dendritic arbor shrinkage of the affected neurons. It is concluded therefore that DHEAS, has the efficacy as testosterone, and that it can exert its effects on the central neuron level to effectively ameliorate aging symptoms.

Genistein partly eases aging and estropause-induced primary cortical neuronal changes in rats.

Gonadal hormones can modulate brain morphology and behavior. Recent studies have shown that hypogonadism could result in cortical function deficits. To this end, hormone therapy has been used to ease associated symptoms but the risk may outweigh the benefits. Here we explored whether genistein, a phytoestrogen, is effective in restoring the cognitive and central neuronal changes in late middle age and surgically estropause female rats. Both animal groups showed poorer spatial learning than young adults. The dendritic arbors and spines of the somatosensory cortical and CA1 hippocampal pyramidal neurons were revealed with intracellular dye injection and analyzed. The results showed that dendritic spines on these neurons were significantly decreased. Remarkably, genistein treatment rescued spatial learning deficits and restored the spine density on all neurons in the surgically estropause young females. In late middle age females, genistein was as effective as estradiol in restoring spines; however, the recovery was less thorough than on young OHE rats. Neither genistein nor estradiol rectified the shortened dendritic arbors of the aging cortical pyramidal neurons suggesting that dendritic arbors and spines are differently modulated. Thus, genistein could work at central level to restore excitatory connectivity and appears to be potent alternative to estradiol for easing aging and menopausal syndromes.

Ascorbic acid and α-tocopherol supplement starting prenatally enhances the resistance of nucleus tractus solitarius neurons to hypobaric hypoxic challenge.

Hypobaric hypoxia, encountered at high altitude, could result in severe consequences. Ascorbic acid (AA) and α-tocopherol (αTC), the two readily available over-the-counter antioxidants, are known to protect nervous tissue against oxidative stress. Here we study whether AA or αTC supplement starting prenatally protects animals against hypobaric hypoxic challenge at adulthood. Expressions of c-fos and the NR1 subunit of the N-methyl-D-aspartate receptors in the nucleus tractus solitarius (NTS) subserving cardiorespiratory functions were investigated. AA and αTC supplement reduced the number of c-fos immunoreactive neurons and intensity of NR1 expression in young and adult animals under normoxia. The treatment, in addition, attenuated the activation of NTS neurons, in terms of c-fos and NR1 expressions, and reduced the anxiety behaviors of adult rats subjected to hypobaric hypoxic challenge. Reduction of c-fos immunoreactive neurons was found concentrated in the chemoreceptor, baroreceptor, and tracheobronchial tree NTS subnuclei that receive corresponding afferents. The protective effect was not found in normal adult animals supplemented with AA or αTC a week before hypobaric hypoxic challenge. In short, prenatal and sustained AA or αTC supplement altered NTS substrate and ameliorated animals' reactions to hypobaric hypoxic insult, suggesting that this may be considered to protect animals from hypoxic insults from young to adult.

Outpatient varicocelectomy performed under local anesthesia.

AIM: To report a series of varicocelectomy performed under pure local anesthesia. METHODS: From July 1988 to June 2003, a total of 575 patients, aged between 15 and 73 years, underwent high ligation of the internal spermatic vein for treatment of a varicocele testis under a regional block in which a precise injection of 0.8 % lidocaine solution was delivered to involved tissues after exact anatomical references were made. A 100-mm visual analog scale (VAS) was used to assess whether the pain level was acceptable. RESULTS: The surgeries were bilateral in 52 cases, and unilateral in 523 cases. All were successfully performed on an outpatient basis except in the case of two patients, who were hospitalized because their surgeries required general anesthesia. Overall, 98.6 % (567/575) of men could go back to work by the end of the first post-operative week and only 8 (1.4 %) men reported feeling physical discomfort on the eighth day. The VAS scores varied from 11 mm to 41 mm with an average of (18.5+/-11.3) mm that was regarded as tolerable. CONCLUSION: This study has shown varicocelectomy under local anesthesia to be possible, simple, effective, reliable and reproducible, and a safe method with minimal complications. It offers the advantages of more privacy, lower morbidity, with no notable adverse effects resulting from anesthesia, and a more rapid return to regular physical activity with minor complications.