Profiles of 5α-Reduced Androgens in Humans and Eels: 5α-Dihydrotestosterone and 11-Ketodihydrotestosterone Are Active Androgens Produced in Eel Gonads

Although 11-ketotestosterone (11KT) and testosterone (T) are major androgens in both teleosts and humans, their 5α-reduced derivatives produced by steroid 5α-reductase (SRD5A/srd5a), i.e., 11-ketodihydrotestosterone (11KDHT) and 5α-dihydrotestosterone (DHT), remains poorly characterized, especially in teleosts. In this study, we compared the presence and production of DHT and 11KDHT in Japanese eels and humans. Plasma 11KT concentrations were similar in both male and female eels, whereas T levels were much higher in females. In accordance with the levels of their precursors, 11KDHT levels did not show sexual dimorphism, whereas DHT levels were much higher in females. It is noteworthy that plasma DHT levels in female eels were higher than those in men. In addition, plasma 11KDHT was undetectable in both sexes in humans, despite the presence of 11KT. Three srd5a genes (srd5a1, srd5a2a and srd5a2b) were cloned from eel gonads. All three srd5a genes were expressed in the ovary, whereas only both srd5a2 genes were expressed in the testis. Human SRD5A1 was expressed in testis, ovary and adrenal, whereas SRD5A2 was expressed only in testis. Human SRD5A1, SRD5A2 and both eel srd5a2 isoforms catalyzed the conversion of T and 11KT into DHT and 11KDHT, respectively, whereas only eel srd5a1 converted T into DHT. DHT and 11KDHT activated eel androgen receptor (ar)α-mediated transactivation as similar fashion to T and 11KT. In contrast, human AR and eel arβ were activated by DHT and11KDHT more strongly than T and 11KT. These results indicate that in teleosts, DHT and 11KDHT may be important 5α-reduced androgens produced in the gonads. In contrast, DHT is the only major 5α-reduced androgens in healthy humans.

[A Case of Gastric Cancer That Pathological Completely Responded to Neoadjuvant S-1 plus Cisplatin Therapy]

A 67-year-old man with complaints of upper abdominal pain visited a clinic and was diagnosed with type 3 gastric cancer. Contrasted-enhanced CT revealed gastric wall thickening and extensive metastatic lymph nodes particularly around the celiac artery and also invasion to pancreas. He was diagnosed with cT4b, cN2, cM0, cStage ⅢB and we treated with neoadjuvant chemotherapy(NAC)consisting of 4 courses of S-1 and cisplatin regimen. After the NAC, primary cancer and metastatic lymph nodes were reduced remarkably. A curative operation could be performed and the histopathological examination showed"Grade 3, pathological complete response".

[A Case of Granulocyte-Colony Stimulating Factor Producing Ascending Colon Cancer]

A 59-year-old man with chief complaints of right-sided rib pain and fever was admitted to our hospital. A type 2 tumor in the ascending colon was revealed by total colonoscopy. Computed tomography examination revealed multiple tumors in the liver. The white blood cell count was high as 13,740/μL. Chemotherapy was planned after treatment with antibiotics, but it was not successful. Right colectomy was performed for infection control. mFOLFOX6 therapy was performed, but liver metastases progressed rapidly, and he died on the 39th postoperative day. The immunohistochemistry revealed G-CSF producing colon cancer. G-CSF producing colon cancer progresses rapidly with poor prognosis. It is necessary to think carefully about indication of surgery and chemotherapy.

Peroxisome proliferator-activated receptor alpha is involved in the temperature-induced sex differentiation of a vertebrate

Medaka (Oryzias latipes) is a teleost fish with an XX/XY sex determination system, similar to that of mammals. However, under high temperature conditions, XX medaka is masculinised by elevation of cortisol, the major teleost glucocorticoid. In this study, to identify novel factors in the gonads acting downstream from cortisol during sexual differentiation, we performed RNA sequencing (RNA-seq) analysis using the gonadal regions of larvae reared at normal temperature with and without cortisol, and at high temperature. The RNA-seq and real-time PCR analyses showed that expression of some peroxisome proliferator-activated receptor α (PPARα) signalling-targeted genes was increased by cortisol. PPARα agonist treatment induced masculinisation of XX medaka in some cases, and co-treatment of the agonist with cortisol further induced masculinisation, whereas treatment of pparaa knockout medaka with cortisol or the agonist did not induce masculinisation. This study provides the first evidence that PPARα is involved in environmental sex determination in vertebrates.

The prognostic value of the prognostic nutritional index and inflammation-based markers in obstructive colorectal cancer

PURPOSE

Inflammation-based markers predict long-term outcomes of various malignancies. We investigated the relationship between these markers and the long-term survival in obstructive colorectal cancer (OCRC) patients with self-expandable metallic colonic stents (SEMSs) who subsequently received curative surgery.

METHODS

We retrospectively analyzed 72 consecutive pathological stage II and III OCRC patients between 2013 and 2019. The prognostic significance of the prognostic nutritional index (PNI), neutrophil-lymphocyte ratio (NLR), lymphocyte-monocyte ratio (LMR), and platelet-lymphocyte ratio (PLR) was evaluated.

RESULTS

The overall survival (OS), cancer-specific survival, and disease-free survival (DFS) were significantly shorter in the PNI < 35 group than in the PNI ≥ 35 group (p = 0.006, p < 0.001, and p = 0.003, respectively), and multivariate analyses revealed the PNI to be the only inflammation-based marker independently associated with the survival. A PNI < 35 was significantly associated with an elevated CA 19-9 level (p = 0.04) and longer postoperative hospital stay (p = 0.03). Adjuvant chemotherapy was also significantly associated with the OS (p = 0.040) and DFS (p = 0.011) in multivariate analyses.

CONCLUSION

The results showed that the PNI was a potent prognostic indicator. For OCRC patients, both systemic inflammation and the nutrition status seem to be important for predicting the prognosis, and administering adjuvant chemotherapy was very important.

AR420626, a selective agonist of GPR41/FFA3, suppresses growth of hepatocellular carcinoma cells by inducing apoptosis via HDAC inhibition

Background

Hepatocellular carcinoma (HCC) is a major cause of cancer death worldwide and establishment of new chemotherapies for HCC is urgently needed. GPR41 [free fatty acid receptor 3 (FFA3)] is a G protein-coupled receptor for short chain fatty acids, including acetate, propionate, and butyrate. In our previous study, we showed that propionate enhances the cytotoxic effect of cisplatin in HCC cells and that this mechanism is dependent on inhibition of histone deacetylases (HDACs) via GPR41/FFA3. However, the antitumor action of GPR41/FFA3 has not been elucidated.

Methods

In this study, we examined AR420626 as a GPR41-selective agonist in HepG2 and HLE cells. Nude mice were used for HepG2 xenograft studies. The apoptotic effect of AR420626 was evaluated using flow cytometry analysis. Expression of apoptosis-related proteins and HDACs was evaluated by Western immunoblot. Gene silencing of HDAC 3/5/7 and GPR41 was performed using small interfering RNA. Expression of TNF-α mRNA was evaluated by TaqMan real-time polymerase chain reaction.

Results

We found that AR420626, a selective GPR41/FFA3 agonist, suppressed growth of HepG2 xenografts and inhibited proliferation of HCC cells by inducing apoptosis. AR420626 induced proteasome activation through mTOR phosphorylation, which reduced HDAC proteins, and then increased expression of TNF-α.

Conclusion

AR420626, a selective GPR41/FFA3 agonist, may be a candidate as a therapeutic agent for HCC.

Evaluation of 17β-hydroxysteroid dehydrogenase activity using androgen receptor-mediated transactivation

17β-Hydroxysteroid dehydrogenases (17β-HSDs) catalyze the reduction of 17-ketosteroids and the oxidation of 17β-hydroxysteroids to regulate the production of androgens and estrogens. Among them, 17β-HSD type 3 (HSD17B3) is expressed almost exclusively in testicular Leydig cells and contributes to development of male sexual characteristics by converting androstenedione (A4) to testosterone (T). Mutations of HSD17B3 genes cause a 46,XY disorder of sexual development (46,XY DSD) as a result of low T production. Therefore, the evaluation of 17β-HSD3 enzymatic activity is important for understanding and diagnosing this disorder. We adapted a method that easily evaluates enzymatic activity of 17β-HSD3 by quantifying the conversion from A4 to T using androgen receptor (AR)-mediated transactivation. HEK293 cells were transduced to express human HSD17B3, and incubated medium containing A4. Depending on the incubation time with HSD17B3-expressing cells, the culture media progressively increased luciferase activities in CV-1 cells, transfected with the AR expression vector and androgen-responsive reporter. Culture medium from HSD17B1 and HSD17B5-expressing cells also increased the luciferase activities. This system is also applicable to detect the conversion of 11-ketoandrostenedione to 11-ketotestosterone by HSD17B3. Establishment of HEK293 cells expressing various missense mutations in the HSD17B3 gene associated with 46,XY DSD revealed that this system is effective to evaluate the enzymatic activities of mutant proteins.

Transcriptional Regulation of Müllerian Inhibiting Substance (MIS) and Establishment of a Gonadal Somatic Cell Line Using mis-GFP Transgenic Medaka (Oryzias latipes)

In vertebrate germ cell differentiation, gonadal somatic cells and germ cells are closely related. By analyzing this relationship, it has recently been reported in mammals that primordial germ cells (PGCs), induced from pluripotent stem cells and germline stem cells, can differentiate into functional gametes when co-cultured in vitro with fetal gonadal somatic cells. In some fish species, differentiation into functional sperm by reaggregation or co-culture of gonadal somatic cells and germ cells has also been reported; however, the relationship between gonadal somatic cells and germ cells in these species is not well-understood. Here, we report the transcriptional regulation of Müllerian inhibiting substance (MIS) and the establishment of a gonadal somatic cell line using mis-GFP transgenic fish, in medaka (Oryzias latipes)-a fish model which offers many advantages for molecular genetics. MIS is a glycoprotein belonging to the transforming growth factor β superfamily. In medaka, mis mRNA is expressed in gonadal somatic cells of both sexes before sex differentiation, and MIS regulates the proliferation of germ cells during this period. Using luciferase assays, we found that steroidogenic factor 1 (SF1) and liver receptor homolog 1 (LRH1) activate medaka mis gene transcription, probably by binding to the mis promoter. We also report that mis-GFP transgenic medaka emit GFP fluorescence specific to gonadal somatic cells in the gonads. By fusing Sertoli cells from transgenic medaka with a cell line derived from medaka hepatoma cancer, we produced a hybridoma cell line that expresses gonadal somatic cell-specific markers, including Sertoli and Leydig cell markers. Moreover, embryonic PGCs co-cultured with the established hybridoma, as feeder cells, proliferated and formed significant colonies after 1 week. PGCs cultured for 3 weeks expressed a germ cell marker dnd, as well as the meiotic markers sycp1 and sycp3. Thus, we here provide the first evidence in teleosts that we have successfully established a gonadal somatic cell-derived hybridoma that can induce both the proliferation and meiosis of germ cells.

β-Hydroxybutyrate enhances the cytotoxic effect of cisplatin via the inhibition of HDAC/survivin axis in human hepatocellular carcinoma cells

Ketone bodies, including acetoacetate and β-hydroxybutyrate (βOHB), are produced from acetyl coenzyme A in the liver and then secreted into the blood. These molecules are a source of energy for peripheral tissues during exercise or fasting. βOHB has been reported to inhibit histone deacetylases (HDACs) 1, 3, and 4 in human embryonic kidney 293 cells. Thus, βOHB may regulate epigenetics by modulating HDACs. There have been several reports that the administration of βOHB or induction of a physiological state of ketosis has an antitumor effect; however, the mechanism remains unclear. The aim of this study was to investigate whether βOHB enhances cisplatin-induced apoptosis in hepatocellular carcinoma (HCC) cells by modulating activity and/or expression of HDACs. We found that βOHB significantly enhanced cisplatin-induced apoptosis and cleavage of caspase-3 and -8 in HCC cells. Further, βOHB significantly decreased the expression of HDCA 3/5/6 and survivin in liver hepatocellular (HepG2) cells. In HDAC3/6 gene silencing, survivin expression was significantly decreased, and cisplatin-induced cleavage of caspase-3 was significantly enhanced compared with control in HepG2 cells. In conclusion, βOHB enhanced cisplatin-induced apoptosis via HDAC3/6 inhibition/survivin axis in HepG2 cells, which suggests that βOHB could be a new adjuvant agent for cisplatin chemotherapy.

Store-operated calcium entry (SOCE) contributes to phosphorylation of p38 MAPK and suppression of TNF-α signalling in the intestinal epithelial cells

Calcium influx via store-operated calcium entry (SOCE) has an important role for regulation of vast majority of cellular physiological events. MAPK signalling is also another pivotal modulator of many cellular functions. However, the relationship between SOCE and MAPK is not well understood. In this study, we elucidated the involvement of SOCE in Gα_q/11 protein-mediated activation of p38 MAPK in an intestinal epithelial cell line HT-29/B6. In this cell line, we previously showed that the stimulation of M3 muscarinic acetylcholine receptor (M3-mAChR) but not histamine H1 receptor (H1R) led to phosphorylation of p38 MAPK which suppressed tumor necrosis factor-α (TNF-α)-induced NF-κB signalling through ADAM17 protease-mediated shedding of TNF receptor-1 (TNFR1). First, we found that stimulation of M3-mAChR and protease-activated receptor-2 (PAR-2) but not H1R induced persistent upregulation of cytosolic Ca²⁺ concentration through SOCE. Activation of M3-mAChR or PAR-2 also suppressed TNF-α-induced NF-κB phosphorylation, which was dependent on the p38 MAPK activity. Time course experiments revealed that M3-mAChR stimulation evoked intracellular Ca²⁺-dependent early phase p38 MAPK phosphorylation and extracellular Ca²⁺-dependent later phase p38 MAPK phosphorylation. This later phase p38 MAPK phosphorylation, evoked by M3-mAChRs or PAR-2, was abolished by inhibition of SOCE. Thapsigargin or ionomycin also phosphorylate p38 MAPK by Ca²⁺ influx through SOCE, leading to suppression of TNF-α-induced NF-κB phosphorylation. Finally, we showed that p38 MAPK was essential for thapsigargin-induced cleavage of TNFR1 and suppression of TNF-α-induced NF-κB phosphorylation. In conclusion, SOCE is important for p38 MAPK phosphorylation and is involved in TNF-α signalling suppression.

Cyclooxygenase-2 is acutely induced by CCAAT/enhancer-binding protein β to produce prostaglandin E 2 and F 2α following gonadotropin stimulation in Leydig cells

Cyclooxygenase 2 (COX-2) is an inducible rate-limiting enzyme for prostanoid production. Because COX-2 represents one of the inducible genes in mouse mesenchymal stem cells upon differentiation into Leydig cells, we investigated COX-2 expression and production of prostaglandin (PG) in Leydig cells. Although COX-2 was undetectable in mouse testis, it was transiently induced in Leydig cells by human chorionic gonadotropin (hCG) administration. Consistent with the finding that Leydig cells expressed aldo-keto reductase 1B7 (PGF synthase) and PGE synthase 2, induction of COX-2 by hCG caused a marked increase in testicular PGF _2α and PGE ₂ levels. Using mouse Leydig cell tumor-derived MA-10 cells as a model, it was indicated by reporter assays and electron mobility shift assays that transcription of the COX-2 gene was activated by CCAAT/enhancer-binding protein β (C/EBPβ) with cAMP-stimulation. C/EBPβ expression was induced by cAMP-stimulation, whereas expression of C/EBP homolog protein (CHOP) was robustly downregulated. Transfection of CHOP expression plasmid inhibited cAMP-induced COX-2 promoter activity. In addition, CHOP reduced constitutive COX-2 expression in other mouse Leydig cell tumor-derived TM3 cells. These results indicate that COX-2 is induced in Leydig cells by activation of C/EBPβ via reduction of CHOP expression upon gonadotropin-stimulation to produce PGF _2α and PGE ₂ .

Comparison of the long-term outcomes of the self-expandable metallic stent and transanal decompression tube for obstructive colorectal cancer

AIM

Endoscopic decompression using the self-expandable metallic colonic stent (SEMS) or transanal decompression tube (TDT) can convert emergency surgery into elective one-stage surgery for obstructive colorectal cancer (OCRC). The aim of the present study was to clarify the effect of SEMS and TDT on long-term oncological outcomes.

METHODS

We retrospectively analyzed 76 consecutive pathological stage II and III OCRC patients who were inserted with SEMS or TDT as a bridge to curative surgery between 2009 and 2018.

RESULTS

There were 53 SEMS cases and 23 TDT cases. The tumor was located in the left colon in 58 cases and in the right colon in 18 cases. The interval between the decompression and the surgery was 16.5 days in the SEMS group and 13.0 days in the TDT group (P = 0.09). Technical and clinical success rates were 100% and 100% for SEMS, and 95% and 91% for TDT, respectively. Stoma was created in four patients in the SEMS group, and in five in the TDT group (P = 0.08). Three-year overall survival rates of the SEMS and TDT groups were 82% and 86% (P = 0.94), and disease-free survival rates were 68% and 62% (P = 0.79), respectively. The recurrence pattern was not significantly different.

CONCLUSION

This study found no statistically significant differences between the effects of SEMS and TDT for OCRC as a bridge to surgery on long-term outcomes.

Involvement of Heat Shock Proteins on the Transcriptional Regulation of Corticotropin-Releasing Hormone in Medaka

Medaka (Oryzias latipes) are teleost fish with a XX/XY sex determination system. Recently, it was reported that high temperature (HT) induced the masculinization of XX medaka by increasing the levels of cortisol, a major glucocorticoid produced by interrenal cells in teleosts. Cortisol secretion is regulated by adrenocorticotropic hormone (ACTH) secreted from the pituitary gland, which is partly regulated by corticotropin-releasing hormone (CRH) secreted from the hypothalamus. In teleosts, two crh paralogs, named crha and crhb, have been identified. Recently, the expression of crhb but not crha was upregulated by HT during gonadal sex differentiation period in medaka and loss-of-functions of its receptors under HT suppressed masculinization of XX medaka and increase of cortisol levels, suggesting that crhb is involved in masculinization induced by HT. However, the transcriptional regulation of crhb under HT has not been elucidated. We analyzed the gene expression pattern in the hypothalamus of medaka embryos incubated under HT using DNA microarray. The expressions of heat shock protein (hsp) genes, such as hsp70.1 and hsp30, were increased. Overexpression of hsp70.1 or hsp30 in cultured rat hypothalamic 4B cells significantly induced crh gene expression. Moreover, hypothalamic hsp70.1-overexpressing transgenic medaka also showed increased crhb gene expression that increased cortisol levels compared with fish incubated at a normal temperature. These results provide the first evidence that HSPs induce cortisol levels by elevating crhb gene expression in the hypothalamus.

A short-chain fatty acid, propionate, enhances the cytotoxic effect of cisplatin by modulating GPR41 signaling pathways in HepG2 cells

Short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate are generated by microbial fermentation of indigestible fiber by gut flora. SCFAs are ligands of two orphan G protein-coupled receptors, GPR41 and GPR43, that modulate cell proliferation and induce apoptosis. However, it is unclear if SCFAs enhance the effects of chemotherapy in a GPR41- or GPR43-dependent manner. The aim of this study was to investigate whether SCFAs, and particularly propionate, activate GPR41 or GPR43, and thereby enhance the antitumor effects of cisplatin in HepG2 human hepatocellular carcinoma (HCC) cells. The inhibitory effects of propionate and cisplatin on proliferation of HCC cells were determined by MTS assay. Changes in apoptosis rate were analyzed by flow cytometry. The effects of combined propionate and cisplatin on these properties in HCC cells were significantly higher than those of cisplatin alone. With combined treatment, the levels of cleaved caspase-3, active caspase-3 forms, and acetylated histone H3 were enhanced in a GPR41-dependent manner; expression of histone deacetylases (HDAC) 3, 4, 5, 6, 8 proteins was significantly reduced; and induction of TNF-α expression was significantly enhanced. These results suggest that propionate and cisplatin synergistically and significantly induce apoptosis of HepG2 cells by increasing expression of autocrine TNF-α via reduction of HDACs through GPR41 signaling. From clinical and translational perspectives, our data suggest that a combination of propionate with cisplatin may have better therapeutic effects on HCC compared with conventional treatment, and that a selective GPR41 agonist may be a candidate as an adjuvant therapeutic agent for HCC.

Induction of steroidogenic cells from adult stem cells and pluripotent stem cells [Review]

Steroid hormones are mainly produced in adrenal glands and gonads. Because steroid hormones play vital roles in various physiological processes, replacement of deficient steroid hormones by hormone replacement therapy (HRT) is necessary for patients with adrenal and gonadal failure. In addition to HRT, tissue regeneration using stem cells is predicted to provide novel therapy. Among various stem cell types, mesenchymal stem cells can be differentiated into steroidogenic cells following ectopic expression of nuclear receptor (NR) 5A subfamily proteins, steroidogenic factor-1 (also known as adrenal 4 binding protein) and liver receptor homolog-1, with the aid of cAMP signaling. Conversely, these approaches cannot be applied to pluripotent stem cells, such as embryonic stem cells and induced pluripotent stem cells, because of poor survival following cytotoxic expression of NR5A subfamily proteins. However, if pluripotent stem cells are first differentiated through mesenchymal lineage, they can also be differentiated into steroidogenic cells via NR5A subfamily protein expression. This approach offers a potential suitable cells for future regenerative medicine and gene therapy for diseases caused by steroidogenesis deficiencies. It represents a powerful tool to investigate the molecular mechanisms involved in steroidogenesis. This article highlights our own and current research on the induction of steroidogenic cells from various stem cells. We also discuss the future direction of their clinical application.

11-Ketotestosterone Is a Major Androgen Produced in Human Gonads

CONTEXT

11-ketotestosterone (11-KT) is a novel class of active androgen. However, the detail of its synthesis remains unknown for humans.

OBJECTIVE

The objective of this study was to clarify the production and properties of 11-KT in human. Design, Participants, and Methods: Expression of cytochrome P450 and 11β-hydroxysteroid dehydrogenase types 1 and 2 (key enzymes involved in the synthesis of 11-KT) were investigated in human gonads. The production of 11-KT was investigated in Leydig cells. Plasma concentrations of testosterone and 11-KT were measured in 10 women and 10 men of reproductive age. Investigation of its properties was performed using breast cancer-derived MCF-7 cells.

RESULTS

Cytochrome P450 and 11β-hydroxysteroid dehydrogenase types 1 and 2 were detected in Leydig cells and theca cells. Leydig cells produced 11-KT, and relatively high levels of plasma 11-KT were measured in both men and women. There was no sexual dimorphism in the plasma levels of 11-KT, even though testosterone levels were more than 20 times higher in men than in women. It is noteworthy that the levels of testosterone and 11-KT were similar in women. In a luciferase reporter system, 11-KT activated human androgen receptor-mediated transactivation. Conversely, 11-KT did not activate estrogen receptor-mediated transactivation in aromatase-expressed MCF-7 cells, whereas testosterone did following conversion to estrogen. 11-KT did not affect the estrogen/estrogen receptor -mediated cell proliferation of MCF-7 cells. Furthermore, it significantly inhibited cell proliferation when androgen receptor was transfected into MCF-7 cells.

CONCLUSIONS

The current study indicates that 11-KT is produced in the gonads and represents a major androgen in human. It can potentially serve as a nonaromatizable androgen.

Regulation of Steroidogenesis, Development, and Cell Differentiation by Steroidogenic Factor-1 and Liver Receptor Homolog-1

Steroidogenic factor-1 (SF-1) and liver receptor homolog-1 (LRH-1) belong to the nuclear receptor superfamily and are categorized as orphan receptors. In addition to other nuclear receptors, these play roles in various physiological phenomena by regulating the transcription of target genes. Both factors share very similar structures and exhibit common functions. Of these, the roles of SF-1 and LRH-1 in steroidogenesis are the most important, especially that of SF-1, which was originally discovered and named to reflect such roles. SF-1 and LRH-1 are essential for steroid hormone production in gonads and adrenal glands through the regulation of various steroidogenesis-related genes. As SF-1 is also necessary for the development of gonads and adrenal glands, it is also considered a master regulator of steroidogenesis. Recent studies have clearly demonstrated that LRH-1 also represents another master regulator of steroidogenesis, which similarly to SF-1, can induce differentiation of non-steroidogenic stem cells into steroidogenic cells. Here, we review the functions of both factors in these steroidogenesis-related phenomena.

[Curative Surgery for Advanced Gastric Cancer with Extensive Lymph Node Metastasis after Long-Term Chemotherapy]

A 65-year-old man was diagnosed with HER2-positive gastric cancer considered unresectable owing to multiple distant lymph node metastases. After long-term chemotherapy, the original lesion disappeared, while peri-gastric lymph node metastases remained. Therefore, we performed lower mediastinal lymph node dissection, total gastrectomy with regional lymph node dissection (D2) and cholecystectomy. Pathological evaluation indicated that the main gastric tumor showed complete response, while there was metastasis in the No.3 lymph nodes, which showed HER2 positivity (3+). At present, the patient has received Xeloda plus trastuzumab and remains relapse-free 5 months after conversion surgery.

[Two cases of rectal NET excised by laparoscopic surgery]

Even if grade 1 neuroendocrine tumors (NET) have low malignant potential, they may still be associated with lymph node metastasis. While the World Health Organization (WHO) classification requires determination of the grade of malignancy and presence of metastasis, it is also useful to evaluate tumor diameter, extent of invasion, and histological characteristics(cell variant, nuclear atypia, and ductal invasion). The authors present 2 cases of rectal NET excised by laparoscopic surgery. Considerations for surgical indications in rectal NET are made based on these case reports.

Tactile sensor is useful for estimating liver hardness and liver fibrosis compared with ultrasonography and computed tomography

BACKGROUND/AIMS

We examined whether conventional ultrasonography (US) and computed tomography (CT) were useful to evaluate liver hardness and hepatic fibrosis by comparing the results with those obtained by a tactile sensor using rats with liver fibrosis.

METHODOLOGY

We used 44 Wistar rats in which liver fibrosis was induced by intraperitoneal administration of thioacetamide. The CT and US values of each liver were measured before laparotomy. After laparotomy, a tactile sensor was used to measure liver hardness. We prepared Azan stained sections of each excised liver specimen and calculated the degree of liver fibrosis (HFI: hepatic fibrosis index) by computed color image analysis.

RESULTS

The stiffness values and HFI showed a positive correlation (r=0.690, p<0.001), as did the tactile values and HFI (r=0.709, p<0.001).In addition, the stiffness and tactile values correlated positively with each other (r=0.814, p<0.001). There was no correlation between the CT values and HFI, as well as no correlation between the US values and HFI.

CONCLUSION

We confirmed that it was difficult to evaluate liver hardness and HFI by CT or US examination, and considered that, at present, a tactile sensor is useful method for evaluating HFI.