The vascular stem cell niches and their significance in the brain

AIM

This cytohistopathological study was performed for a better knowledge of phenotypes derived from pluripotent stem cells, as well as for precise location of stem cells within the vascular niche in the brain.

METHODS

We used light and transmission electron microscopy to demonstrate the presence of stem cells in the vascular wall of microvessels in the cerebral and cerebellar cortex, pia mater (considered by us a cordocytic-vascular tissue), adventitia of larger cortical arteries and veins, and around vessels. We investigated multiple vascular segments and brain tissue in a variety of clinical cases, such as cerebral tumors, cerebrovascular malformations, thromboses in the carotid system, and direct laceration.

RESULTS

Our morphological and ultrastructural observations pointed out many changing phenotypes, as well as cell interrelationships within the vascular niche, both for repair processes when cordocytes cooperate with mesenchymal stem cells, and pathological processes such as atherogenesis, tumorigenesis, and neurotrauma. Our results underlie the important roles of cordocytes in their interrelations with precursor/stem cells in the arterial adventitia.

CONCLUSION

The cells derived from pluripotent stem cells along different lineages have had different phenotypes as they derived from hematopoietic stem cells or mesenchymal stem cells, with or without epigenetic disregulations or depending on different microenvironments. Cell interactions, phenotypes, and underlying mechanisms, as well as biological responses to different small molecules or compounds, remain to be determined by future molecular insights within the vascular niche.

Apoptosis, paraptosis, necrosis, and cell regeneration in posttraumatic cerebral arteries

This study is to understand the nature and functional significance of the activated cell death programs and rehabilitation signs during late vascular changes after brain injury. We used light and transmission electron microscopy to describe changes of cells within the vascular endothelium and tunica media of the cortical arteries four weeks after craniocerebral traumatism. Within tunica media of the posttraumatic damaged artery, apoptotic and paraptotic phenotypes were identified as well as some early ultrastructural signs of smooth muscle cells regeneration, these cell highlighting a remarkable degree of plasticity. Surprisingly, some endothelial cells showed an extensive rough endoplasmic reticulum development, whereas other endothelial cells showed typical necrosis. In conclusion, two groups of suicidal cells apoptotic and paraptotic cells were encountered in the same lesional vascular wall after neurotrauma, showing also signs of cell regeneration. The pathophysiologic significance of the coexisting double cell death programs and cell regeneration seems to be in relation with late cell survival, after arterial damage when some cells disappear and other cells try to survive undergoing reversible injury.

Resident Burnout: What to do About it?

Background:

Burnout is a prolonged response to chronic emotional and interpersonal stressors on the job, and is defined by the three dimensions of exhaustion, cynicism and inefficacy. Resident physicians have intense work demands, limited control and high responsibilities in the workplace, making them more vulnerable to job burnout.

Aim:

To review studies in the medical literature that address the theme of burnout in residents and discuss relevant resources and interventions for residents with burnout.

Methods:

MEDLINE and PubMed databases searches for peer-reviewed studies, published between 1990 and 2008, using combinations of the Medline Subject Heading terms professional burnout and internship and residency.

Results:

The studies report high levels of burnout among residents. The reported residents’ strategies for coping with stress are diverse and include talking with family, significant others or other residents and practicing physical activity. Some studies investigated the role of stress management workshops for residents, reporting decline of emotional exhaustion levels in residents after the workshops.

Discussion:

The literature on resident burnout is still sparse. The reviewed studies suggest that residents from various specialties, internationally, experience burnout. Understanding resident burnout can be enhanced by more rigorous research, studying different intervention strategies. Burnout prevention and management can contribute to better personal outcomes and ultimately provide better patient care.

Adenocarcinoma of the urachus associated with elevated levels of CA 125

Adenocarcinoma of the urachus is a rare genitourinary tumor with a poor prognosis. The treatment of choice is en bloc surgical resection, although combination therapy with surgery and chemotherapy has been used with mixed results. We describe a 69-year-old woman with adenocarcinoma of the urachus and elevated serum levels of CA 125 tumor marker. She was treated with resection plus 5-fluorouracil, doxorubicin and mitomycin, alternating with platinum-based chemotherapy. The serum CA 125 level decreased precipitously after the operation and became normal after 2 months of chemotherapy. The patient remained free of disease 1 year postoperatively. Serum CA 125 may be a useful tumor marker for urachal carcinoma and adjuvant chemotherapy may be effective in treating the disease.