The Actions of Sevoflurane and Desflurane on the γ-Aminobutyric Acid Receptor Type A: Effects of TM2 Mutations in the α and β Subunits

Background: Previous studies have shown that specific amino acid residues in the putative second transmembrane segment (TM2) of the [gamma]-aminobutyric acid receptor type A (GABAA) receptor play a critical role in the enhancement of GABAA receptor function by halothane, enflurane, and isoflurane. However, very little is known about the actions of sevoflurane and desflurane on recombinant GABAA receptors. The aim of this study was to examine the effects of sevoflurane and desflurane on potentiation of GABA-induced responses in the wild-type GABAA receptor and in receptors mutated in TM2 of the [alpha]1, [alpha]2, or [beta]2 subunits.

Methods: GABAA receptor [alpha]1 or [alpha]2, [beta]2 or [beta]3, and [gamma]2s subunit cDNAs were expressed for pharmacologic study by transfection of human embryonic kidney 293 cells and assayed using the whole cell voltage clamp technique. Concentration-response curves and EC50 values for agonist were determined in the wild-type [alpha]1[beta]2[gamma]2s and [alpha]2[beta]3[gamma]2s receptors, and in receptors harboring mutations in TM2, such as [alpha]1(S270W)[beta]2[gamma]2s, [alpha]1[beta]2(N265W)[gamma]2s, and [alpha]2(S270I)[beta]3[gamma]2s. The actions of clinically relevant concentration of volatile anesthetics (isoflurane, sevoflurane, and desflurane) on GABA activated Cl- currents were compared in the wild-type and mutant GABAA receptors.

Results: Both sevoflurane and desflurane potentiated submaximal GABA currents in the wild-type GABAA [alpha]1[beta]2[gamma]2s receptor and [alpha]2[beta]3[gamma]2s receptor. Substitution of Ser270 in TM2 of the [alpha] subunit by a larger amino acid, tryptophan (W) or isoleucine (I), as in [alpha]1(S270W)[beta]2[gamma]2s and [alpha]2(S270I)[beta]3[gamma]2s, completely abolished the potentiation of GABA-induced currents by these anesthetic agents. In contrast, mutation of Asn265 in TM2 of the [beta] subunit to tryptophan (W) did not prevent potentiation of GABA-induced responses. The actions of sevoflurane and desflurane in the wild-type receptor and in mutated receptors were qualitatively and quantitatively similar to those observed for isoflurane.     

Epidural clonidine suppresses the baroreceptor-sympathetic response depending on isoflurane concentrations in cats

Epidural administration of clonidine induces hypotension and bradycardia secondary to decreased sympathetic nerve activity. In this study, we sought to elucidate the change in baroreflex response caused by epidural clonidine. Thirty-six cats were allocated to six groups (n = 6 each) and were given either thoracic epidural clonidine 4 micro g/kg or lidocaine 2 mg/kg during 0.5, 1.0, or 1.5 minimum alveolar anesthetic concentration (MAC) isoflurane anesthesia. Heart rate (HR), mean arterial blood pressure (MAP), and cardiac sympathetic nerve activity (CSNA) were measured. Depressor and pressor responses were induced by IV nitroprusside 10 micro g/kg and phenylephrine 10 micro g/kg, respectively. Baroreflex was evaluated by the change in both CSNA and HR relative to the peak change in MAP (deltaCSNA/deltaMAP and deltaHR/deltaMAP, respectively). These measurements were performed before and 30 min after epidural drug administration. Epidural clonidine and lidocaine decreased HR, MAP, and CSNA by similar extents. deltaCSNA/deltaMAP and deltaHR/deltaMAP for depressor response were suppressed with epidural lidocaine and clonidine in all groups but the clonidine 0.5 MAC isoflurane group (0.197 +/- 0.053 to 0.063 +/- 0.014 and 0.717 +/- 0.156 to 0.177 +/- 0.038, respectively, by epidural lidocaine [P < 0.05] but 0.221 +/- 0.028 to 0.164 +/- 0.041 and 0.721 +/- 0.177 to 0.945 +/- 0.239, respectively, by epidural clonidine during 0.5 MAC isoflurane). Those for pressor response were suppressed in all groups. We conclude that thoracic epidural clonidine suppresses baroreflex gain during isoflurane anesthesia >1.0 MAC but may offer certain advantages compared with epidural lidocaine during 0.5 MAC isoflurane by virtue of preserving baroreflex sensitivity when inadvertent hypotension occurs.     

Hemangioma in the anterior mediastinum

Anterior mediastinal hemangiomas are very rare neoplasms in mediastinal tumors. A 58-year-old woman was revealed to have a mass measuring 4×3 cm in size in the anterior mediastinum with calcification on computed tomography. It was initially suspected to be a thymoma. We performed tumor extirpation in November 1998. The tumor was close to the thymus and slightly adhered to the superior vena cava, ascending aorta and right phrenic nerve, however, it did not invade any surrounding organs. Histopathologically, it was diagnosed to be a venous type hemangioma composed of vessels covered by smooth muscle and a cavernous type hemangioma composed of dilated vessels covered by one layer of endothelial cells.     

Clinical significance of mucinous components in rectal cancer after preoperative chemoradiotherapy

Purpose

The clinical implications of mucinous components in rectal tumors, especially with regard to the efficacy of neoadjuvant chemoradiotherapy, remain unclear.

Methods

One hundred and thirty rectal cancer patients who received curative resection after neoadjuvant chemoradiotherapy were retrospectively reviewed. Patients were classified into 3 groups according to the proportion of extracellular mucin: low (<5 %), moderate (5–25 %), and high (>25 %).

Results

There were 82 (63.1 %), 26 (20.0 %), and 22 (16.9 %) patients in the low, moderate, and high mucin groups, respectively. Patients with a high mucinous tumor component were significantly more likely to have an advanced tumor stage (p = 0.010) and a shorter disease-free (p = 0.002) and distant recurrence-free survivals (p < 0.001), whereas the mucinous tumor component showed no correlation with local recurrence (p = 0.101). A high mucinous component was also an independent predictive factor for a shorter disease-free survival (p = 0.041, hazard ratio = 2.56) and distant recurrence-free survival (p = 0.001, hazard ratio = 5.74) according to a multivariate analysis.

Conclusions

Because the mucinous components showed little correlation with local recurrence, mucinous cancer should not be a determining factor for chemoradiotherapy. However, the frequent occurrence of metachronous distant metastasis among patients with a high mucin component makes this a possible indicator for more robust postoperative adjuvant treatment and close surveillance of recurrence.

     

Intraluminal lavage to remove exfoliated tumor cells after colorectal endoscopic submucosal dissection

Background

Endoscopic submucosal dissection (ESD) involves dissection of tumors and manipulation of them in an exposed condition for prolonged periods. A large number of tumor cells are exfoliated into the intestinal lumen after colorectal ESD. The aim of this study was to determine whether lavage volume has an influence on tumor cell clearance after colorectal ESD.

Methods

Twenty patients who underwent colorectal ESD at our hospital between July 2013 and December 2014 were studied. Cytological examination of intraluminal lavage samples associated incremental increases in lavage volume was collected. This prospective study was approved by the ethics committee of our hospital.

Results

No patients had exfoliated tumor cells in their samples before ESD. Four patients (20 %) had exfoliated tumor cells in their samples after lavage with 500 ml, while one patient (5 %) had exfoliated tumor cells after lavage with 1000 or 1500 ml.

Conclusion

Tumor cells are exfoliated into the intestinal lumen by tumor manipulation during colorectal ESD. There seems to be a risk for implantation after ESD, as well as rectal surgery. Sufficient intraluminal lavage of more than 1000 ml may be desirable to remove exfoliated tumor cells after colorectal ESD.

     

Development of a compact laparoscope manipulator (P-arm)

Background

Laparoscope manipulating robots are useful for maintaining a stable view during a laparoscopic operation and as a substitute for the surgeon who controls the laparoscope. However, there are several problems to be solved. A large apparatus sometimes interferes with the surgeon. The setting and repositioning is awkward. Furthermore, the initial and maintenance costs are expensive. This study was designed to develop a new laparoscope manipulating robot to overcome those problems.

Methods

We developed a compact robot applicable for various types of laparoscopic surgery with less expensive materials. The robot was evaluated by performing an in vitro laparoscopic cholecystectomy using extracted swine organs. Then, the availability of the robot to various operations was validated by performing a laparoscopic cholecystectomy, anterior resection of the rectum, and distal gastrectomy using a living swine. The reliability of the system was tested by long-time continuous running.

Results

A compact and lightweight laparoscope manipulating robot by the name of P-arm was developed. The surgical time of an in vitro laparoscopic cholecystectomy with and without the P-arm was not different. The three types of operations were accomplished successfully. During the entire procedure, the P-arm worked without trouble and did not interfere with the surgeons. Continuous 8-h operating tests were performed three times and neither discontinuance nor trouble occurred with the system.

Conclusions

The P-arm worked steadily for various swine operations, without interfering with surgeon’s work.     

CD133 Expression at the Metastatic Site Predicts Patients’ Outcome in Colorectal Cancer with Synchronous Liver Metastasis

Background

CD133 is a transmembrane protein that is proposed to be a stem cell marker of colorectal cancer (CRC); however, the correlation between CD133 expression and survival of CRC patients with liver metastasis has not been fully examined.

Methods

CD133 expression was evaluated immunohistochemically, both in primary tumors and synchronous liver metastases of 88 consecutive CRC patients, as well as recurrent lesions in the remnant liver of 27 of these 88 patients. The relationship between CD133 expression and clinicopathological characteristics, recurrence-free survival, and overall survival (OS) was analyzed.

Results

CD133 expression in liver metastases (mCD133) was detected in 50 of 88 patients (56.8 %), and had significant correlation with CD133 expression in primary lesions (pCD133) (p < 0.001). CD133 expression in liver recurrent lesions (recCD133) also had a significant correlation with mCD133 (p < 0.001). mCD133+ patients had significantly longer disease-free survival (p = 0.043) and OS (p = 0.014) than mCD133? patients. In addition, mCD133+ patients had a significantly lower rate of extrahepatic recurrence (p < 0.001).

Conclusions

Patients without CD133 expression in liver metastasis had significantly shorter survival, perhaps because mCD133? patients had a significantly higher rate of extrahepatic recurrence.

     

An immunohistochemical study of normal sweat glands using an antibody to the breast cyst fluid protein (GCDFP-15)

In this study, we applied the antibody against the molecular weight 15,000 protein purified from breast cyst fluid (GCDFP-15) to cutaneous tissue, especially to sweat glands. Breast cyst fluid was obtained by needle aspiration from patients with gross cystic disease. DEAE-cellulose column chromatography was performed and followed by SDS-polyacrylamide gel electrophoresis. Antisera against the purified protein were prepared in rabbits. We stained specimens of normal skin by the PAP method. The normal apocrine gland cells were strong positive and eccrine gland dark cells were positive. Eccrine gland clear cells were weak positive or negative. Duct cells of both glands were negative. From these observations, we suggest that this antibody is useful for detecting seromucous cells of sweat glands, including both the apocrine gland cells and eccrine dark cells in the skin.     

Primary localized cutaneous nodular amyloidosis: case report and biochemical analysis of amyloid.

We report a patient with scalp lesions of primary localized cutaneous nodular amyloidosis. The extensive examination revealed no systemic involvement. Analysis of glycosaminoglycans (GAGs) in amyloid deposits showed a twofold increase as compared with normal skin, which was due to the increase in dermatan sulfate. Local disorders of GAG metabolism may be related to the amyloid fibril formation. Amyloid fibrils were purified and identified electron-microscopically, which consisted of two major 12,000- and 13,000-dalton and minor 29,000- and 48,000-dalton peptides. Western blotting analysis showed a minor 29,000-dalton peptide reactive with antibodies against both kappa and lambda light chains of immunoglobulin. There is a possibility that some components of amyloid in some cases of primary localized cutaneous nodular amyloidosis may consist of both kappa and lambda immunoglobulin light chains.