Adult localized Langerhans cell histiocytosis: A case report

BACKGROUND

Langerhans cell histiocytosis (LCH) is a rare clonal proliferative disease of Langerhans cells with unknown pathogenesis. An increasing number of clinicians recognize that LCH has a wide clinical spectrum and a highly varied course. Adults rarely develop LCH. Here, we report a case of adult localized LCH.

CASE SUMMARY

A 32-year-old woman presented with plaques and ulcers on the vulva and crissum, accompanied by pain that persisted for more than one year. Physical examination revealed a red-infiltrating plaque with ulcerations and exudates in the vulva and crissum. Pathological examination revealed a diffuse infiltration of lymphocytes, eosinophilic granulocytes, and histiocytoid cells in the superficial dermis. Proliferative histiocytoid cells showed mild atypia, partly with kidney-shaped nuclei. Immunohistochemical examination showed that the histiocytoid cells were positive for S100 protein and CD1 and weakly positive for CD68 (20% +), with a Ki-67 index of 30%. Laboratory tests did not reveal any other systemic damage. The patient was diagnosed with adult localized LCH and was prescribed oral prednisone (20 mg) once daily. The skin lesions gradually improved and are still being followed-up.

CONCLUSION

Adult localized LCH is rare and must be differentiated from other common conditions.

Spatiotemporal characteristics of neural activity in tibial nerves with carbon nanotube yarn electrodes

BACKGROUND

Reliable interfacing with peripheral nervous system is essential to extract neural signals. Current implantable peripheral nerve electrodes cannot provide long-term reliable interfaces due to their mechanical mismatch with host nerves. Carbon nanotube (CNT) yarns possess excellent mechanical flexibility and electrical conductivity. It is of great necessity to investigate the selectivity of implantable CNT yarn electrodes.

NEW METHOD

Neural interfaces were fabricated with CNT yarn electrodes insulated with Parylene-C. Acute recordings were carried out on tibial nerves of rats, and compound nerve action potentials (CNAPs) were electrically evoked by biphasic current stimulation of four toes. Spatiotemporal characteristics of neural activity and spatial selectivity of the electrodes, denoted by selectivity index (SI), were analyzed in detail.

RESULTS

Conduction velocities of sensory afferent fibers recorded by CNT yarn electrodes varied between 4.25 m/s and 37.56 m/s. The SI maxima for specific toes were between 0.55 and 0.99 across seven electrodes. SIs for different CNT yarn electrodes are significantly different among varied toes.

COMPARISON WITH EXISTING METHODS

Most single CNT yarn electrode with a ∼ 500 μm exposed length can be sensitive to one or two specific toes in rodent animals. While, it is only possible to discriminate two non-adjacent toes by multisite TIME electrodes.

CONCLUSION

Single CNT yarn electrode exposed ∼ 500 μm showed SI values for different toes comparable to a multisite TIME electrode, and had high spatial selectivity for one or two specific toes. The electrodes with cross section exposed could intend to be more sensitive to one specific toe.

[Effect of phorbol ester on protein kinase C and tyrosine protein kinase in human hepatocarcinoma cell line]

Phorbol-12-myristate-13-acetate (PMA) induced a dose-dependent proliferation of human hepatocarcinoma cell line SMMC-7721. In the presence of 100 nmol/L PMA, the activity of alkaline phosphatase was decreased and gamma-glutamyltransferase increased in the cell, suggesting that PMA is a proliferative inducer of hepatocarcinoma cell. PMA (100 nmol/L) also lead to a cytosol to membrane translocation of protein kinase C (PKC) within 5 minutes and down regulation after 1 hour. The decline of PKC activity in cytosolic fraction was far faster than that of membranous fraction. After long-term treatment with PMA for 1-5 days, the activities of PKC in cytosolic or membranous fraction almost disappeared, but the tyrosine protein kinase in both subcellular fractions was increased, being most obviously on the third day of culture. The increase in cytosolic TPK was more than that of membranous TPK, further indicating that TPK is a marker of cell proliferation.