Can postoperative deltoid weakness after cervical laminoplasty be prevented by using intraoperative neurophysiological monitoring?

Laminoplasty, frequently performed in patients with cervical myelopathy, is safe and provides relatively good results. However, motor palsy of the upper extremities, which occurs after decompression surgery for cervical myelopathy, often reduces muscle strength of the deltoid muscle, mainly in the C5 myotome. The aim of this study was to investigate prospectively whether postoperative deltoid weakness (DW) can be predicted by performing intraoperative neurophysiological monitoring (IONM) during cervical laminoplasty and to clarify whether it is possible to prevent palsy using IONM. We evaluated the 278 consecutive patients (175 males and 103 females) who underwent French-door cervical laminoplasty for cervical myelopathy under IONM between November 2008 and December 2016 at our hospital. IONM was performed using muscle evoked potential after electrical stimulation to the brain [Br(E)-MsEP] from the deltoid muscle. Seven patients (2.5%) developed DW after surgery (2 with acute and 5 with delayed onset). In all patients, deltoid muscle strength recovered to ≥ 4 on manual muscle testing 3-6 months after surgery. Persistent IONM alerts occurred in 2 patients with acute-onset DW. To predict the acute onset of DW, Br(E)-MsEP alerts in the deltoid muscle had both a sensitivity and specificity of 100%. The PPV of persistent Br(E)-MsEP alerts had both a sensitivity and specificity of 100% for acute-onset DW. There was no change in Br(E)-MsEP in patients with delayed-onset palsy. The incidence of deltoid palsy was relatively low. Persistent Br(E)-MsEP alerts of the deltoid muscle had a 100% sensitivity and specificity for predicting a postoperative acute deficit. IONM was unable to predict delayed-onset DW. In only 1 patient were we able to prevent postoperative DW by performing a foraminotomy.

Trpv4 involvement in the sex differences in blood pressure regulation in spontaneously hypertensive rats.

Arterial pressure (AP) is lower in premenopausal women than in men of a similar age. Premenopausal women exhibit a lower sympathetic activity and a greater baroreceptor reflex; however, mechanisms controlling sex differences in blood pressure regulation are not well understood. We hypothesized that different neuronal functions in the cardiovascular centers of the brains of men and women may contribute to the sex difference in cardiovascular homeostasis. Our previous studies on male spontaneously hypertensive rats (SHRs) and their normotensive counterparts, Wistar Kyoto (WKY) rats, revealed that the gene-expression profile of the nucleus tractus solitarius (NTS), a region of the medulla oblongata that is pivotal for regulating the set point of AP, is strongly associated with AP. Thus, we hypothesized that gene-expression profiles in the rat NTS are related to sex differences in AP regulation. Because female SHRs clearly exhibit lower AP than their male counterparts of a similar age, we investigated whether SHR NTS exhibits sex differences in gene expression by using microarray and RT-qPCR experiments. The transcript for transient receptor potential cation channel subfamily V member 4 ( Trpv4) was found to be upregulated in SHR NTS in females compared with that in males. The channel was expressed in neurons and glial cells within NTS. The TRPV4 agonist 4-alpha-phorbol-12,13-didecanoate (4α-PDD) decreased blood pressure when injected into NTS of rats. These findings suggest that altered TRPV4 expression might be involved in the sex differences in blood pressure regulation.

Flow cytometric isolation and clonal identification of self-renewing bipotent hepatic progenitor cells in adult mouse liver.

UNLABELLED: The adult liver progenitor cells appear in response to several types of pathological liver injury, especially when hepatocyte replication is blocked. These cells are histologically identified as cells that express cholangiocyte markers and proliferate in the portal area of the hepatic lobule. Although these cells play an important role in liver regeneration, the precise characterization that determines these cells as self-renewing bipotent primitive hepatic cells remains to be shown. Here we attempted to isolate cells that express a cholangiocyte marker from the adult mouse liver and perform single cell-based analysis to examine precisely bilineage differentiation potential and self-renewing capability of these cells. Based on the results of microarray analysis and immunohistochemistry, we used an antibody against CD133 and isolate CD133(+) cells via flow cytometry. We then cultured and propagated isolated cells in a single cell culture condition and examined their potential for proliferation and differentiation in vitro and in vivo. Isolated cells that could form large colonies (LCs) in culture gave rise to both hepatocytes and cholangiocytes as descendants, while maintaining undifferentiated cells by self-renewing cell divisions. The clonogenic progeny of an LC-forming cell is capable of reconstituting hepatic tissues in vivo by differentiating into fully functional hepatocytes. Moreover, the deletion of p53 in isolated LC-forming cells resulted in the formation of tumors with some characteristics of hepatocellular carcinoma and cholangiocarcinoma upon subcutaneous injection into immunodeficient mutant mice. These data provide evidence for the stem cell-like capacity of isolated and clonally cultured CD133(+) LC-forming cells. CONCLUSION: Our method for prospectively isolating hepatic progenitor cells from the adult mouse liver will facilitate study of their roles in liver regeneration and carcinogenesis.