Molecular basis of carotid body tumor and associated clinical features in Japan identified by genomic, immunohistochemical, and clinical analyses.

Carotid body tumor (CBT) is classified as a paraganglioma (PGL). Here, we report the genetic background, protein expression pattern, and clinical findings of 30 Japanese CBT cases. Germline pathogenic or likely pathogenic (P/LP) variants of genes encoding succinate dehydrogenase subunits (SDHs) were detected in 15 of 30 cases (50%). The SDHB variants were the most frequently detected, followed by SDHA and SDHD variants. One case with SDHAF2 variant was bilateral CBT, and other two multiple PGL cases were not detected P/LP variants. The three cases with germline variants that could be tested did not have somatic P/LP variants of the same genes. Immunohistochemical analysis showed negative SDHB signals in CBT tissues in five cases with germline P/LP variants of SDHB, SDHD, or SDHA. In addition, SDHB signals in CBT tissues were negative in four of nine cases without germline P/LP variants of SDHs. These findings suggest the involvement of unidentified molecular mechanisms affecting SDHs.

Differential effect of canagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, on slow and fast skeletal muscles from nondiabetic mice.

There has been a concern that sodium-glucose cotransporter 2 (SGLT2) inhibitors could reduce skeletal muscle mass and function. Here, we examine the effect of canagliflozin (CANA), an SGLT2 inhibitor, on slow and fast muscles from nondiabetic C57BL/6J mice. In this study, mice were fed with or without CANA under ad libitum feeding, and then evaluated for metabolic valuables as well as slow and fast muscle mass and function. We also examined the effect of CANA on gene expressions and metabolites in slow and fast muscles. During SGLT2 inhibition, fast muscle function is increased, as accompanied by increased food intake, whereas slow muscle function is unaffected, although slow and fast muscle mass is maintained. When the amount of food in CANA-treated mice is adjusted to that in vehicle-treated mice, fast muscle mass and function are reduced, but slow muscle was unaffected during SGLT2 inhibition. In metabolome analysis, glycolytic metabolites and ATP are increased in fast muscle, whereas glycolytic metabolites are reduced but ATP is maintained in slow muscle during SGLT2 inhibition. Amino acids and free fatty acids are increased in slow muscle, but unchanged in fast muscle during SGLT2 inhibition. The metabolic effects on slow and fast muscles are exaggerated when food intake is restricted. This study demonstrates the differential effects of an SGLT2 inhibitor on slow and fast muscles independent of impaired glucose metabolism, thereby providing new insights into how they should be used in patients with diabetes, who are at a high risk of sarcopenia.

Endoscopic Endonasal Management of Pterygopalatine Fossa Tumors.

ABSTRACT: Surgical removal of pterygopalatine fossa (PPF) tumors with endoscopic endonasal approach is still challenging. The present study aimed to evaluate our endoscopic endonasal management of PPF tumors based on the tumor pathology and purpose of the surgery. This comprised both a single nostril approach for biopsy and a binostril approach for complete resection of benign and noninfiltrating tumors. Based on this strategy, 12 patients underwent endoscopic endonasal surgery for PPF tumors between 2013 and 2018. The patients' data were analyzed retrospectively to demonstrate the significance of our treatment scheme. The surgery was terminated only after taking a biopsy specimen in 6 patients. Other 6 patients underwent gross total resection or bulk tumor reduction. Final pathological diagnosis was malignant in 6 cases and benign in the remaining 6. Post-operative treatment was needed in 7 patients. Four operations for the 6 patients who underwent either debulking or radical surgery were performed by the binostril approach; while 5 surgeries for the 6 biopsy patients were performed by the single nostril approach. Postoperative complications were tolerable. Endoscopic resection should be adopted preferentially for benign tumors that can be removed in a piecemeal fashion. However, as most malignant tumors were impossible to resect with a negative margin, priority should be given to tumor biopsy using an endoscopic approach, which is less invasive than an open approach, and an appropriate treatment customized to the pathological diagnosis should be administered.

Evaluation of a Spray-type, Novel Dextrin Hydrogel Adhesion Barrier Under Laparoscopic Conditions in a Porcine Uterine Horn Adhesion Model.

STUDY OBJECTIVE: To establish a porcine uterine horn adhesion model that mimicked laparoscopic procedures and use it to investigate the effect of a spray-type, novel dextrin hydrogel adhesion barrier (AdSpray; Terumo Corporation, Tokyo, Japan) on postsurgical adhesions. DESIGN: A single-blind randomized controlled trial (Canadian Task Force Classification I). SETTING: A Certified animal research facility. SUBJECTS: Sixteen female pigs. INTERVENTIONS: All animals underwent laparoscopically assisted adhesion-inducing surgery. The uterine horns and the peritoneum of the pelvic sidewall were injured. In the experimental group, AdSpray was applied to the injured site, and the handling of the sprayer was assessed. At 28 ± 1 days after surgery, animals were sacrificed, and adhesions at the injured site were evaluated. Uterine horn suture sites were examined under a light microscope to assess healing of the incised wound, the inflammatory reaction, abscess, and the foreign body reaction to the surgical suture. MEASUREMENTS AND MAIN RESULTS: The control group showed severe adhesions over the entire surface interface at the uterine horn suture sites and peritoneal resection site. Compared with the control treatment, AdSpray exhibited a higher percentage of adhesion-free sites (p < .001) and reduced the total adhesion score (p < .001). In the AdSpray group, no inflammation or abscess formation was observed on histopathological examination, and ideal healing of the suture sites was confirmed in all cases. CONCLUSION: Based on the results of the present study, the novel dextrin hydrogel shows excellent adhesion prevention and can be easily applied during laparoscopy using a dedicated sprayer.

Photochemical characterization of actinorhodopsin and its functional existence in the natural host.

Actinorhodopsin (ActR) is a light-driven outward H+ pump. Although the genes of ActRs are widely spread among freshwater bacterioplankton, there are no prior data on their functional expression in native cell membranes. Here, we demonstrate ActR phototrophy in the native actinobacterium. Genome analysis showed that Candidatus Rhodoluna planktonica, a freshwater actinobacterium, encodes one microbial rhodopsin (RpActR) belonging to the ActR family. Reflecting the functional expression of RpActR, illumination induced the acidification of the actinobacterial cell suspension and then elevated the ATP content inside the cells. The photochemistry of RpActR was also examined using heterologously expressed RpActR in Escherichia coli membranes. The purified RpActR showed λmax at 534nm and underwent a photocycle characterized by the very fast formation of M intermediate. The subsequent intermediate, named P620, could be assigned to the O intermediate in other H+ pumps. In contrast to conventional O, the accumulation of P620 remains prominent, even at high pH. Flash-induced absorbance changes suggested that there exists only one kind of photocycle at any pH. However, above pH7, RpActR shows heterogeneity in the H+ transfer sequences: one first captures H+ and then releases it during the formation and decay of P620, while the other first releases H+ prior to H+ uptake during P620 formation.

[Usefulness and Limitation of Thyroglobulin Measurement in Fine Needle Aspirates (FNA-Tg) for Diagnosis of Neck Lymph Node Metastasis from Thyroid Carcinoma].

BACKGROUND: Preoperative diagnosis of lymph node metastasis from thyroid carcinoma is usually confirmed by using fine needle aspiration cytology (FNAC) when thyroid carcinoma is suspected based on the clinical findings. However, the result of FNAC sometimes leads to a false negative, especially in cases of hypocellular lesions such as metastases with cystic change. Thyroglobulin measurement in fine needle aspirates (FNA-Tg) has been shown to be a useful technique to detect the protein specifically secreted by thyroid follicular cells. Elevated FNA-Tg levels in an extra-thyroidal lesion means that the lesion comprises thyroid-originated tissue, most of which suggests the metastasis from thyroid carcinoma. Thus, FNA-Tg is expected to improve the sensitivity of FNAC for the aforementioned purpose. PATIENTS AND METHODS: From 2008 to 2012, 49 extra-thyroidal lesions from 43 patients with thyroid carcinoma were examined using both FNAC and FNA-Tg, followed by surgical resection with a histopathological diagnosis. The results were retrospectively reviewed and analyzed. RESULTS: Among 49 lesions, 47 were metastatic lymph nodes from thyroid carcinoma (46 papillary carcinoma and one follicular carcinoma), one was a metastatic lymph node from submandibular gland adenocarcinoma, and one was an ectopic thyroid gland. In the 47 cases of thyroid carcinoma, the sensitivity of FNAC was 57.4% (27/47), whereas that of FNA-Tg was 76.6% (36/47). When both methods were combined, the sensitivity increased to 93.6% (44/47). Metastasis from submandibular gland adenocarcinoma was considered to be an example of a false positive from FNAC, whereas an ectopic thyroid gland was an FNA-Tg false positive. Three lesions were negative for both FNAC and FNA-Tg, although metastases were suspected by imaging studies and confirmed by histopathological diagnosis, which were consistent with examples of a false negative from both FNAC and FNA-Tg findings. CONCLUSIONS: FNAC reflects whether the lesion has malignant cells, whereas FNA-Tg reflects whether the lesion has thyroid-originated tissue that specifically secrets thyroglobulin. Therefore, FNAC and FNA-Tg are considered to be complementary to each other for the preoperative diagnosis of lymph node metastasis from thyroid carcinoma. FNA-Tg was validated to improve the preoperative diagnostic sensitivity especially when combined with FNAC, however, it is attended with the possibility of a false positive or negative finding, which requires caution in interpretation of the findings.

Ectopic adrenocorticotropic hormone syndrome in patients with olfactory neuroblastoma.

Olfactory neuroblastomas rarely secrete adrenocorticotropic hormone, leading to ectopic adrenocorticotropic hormone syndrome. However, the prevalence, timing, and triggers of ectopic adrenocorticotropic hormone syndrome in patients with olfactory neuroblastomas remain unclear. This study aimed to investigate these factors and conduct a literature review. Fifteen patients with olfactory neuroblastomas who underwent surgery at our institution were included. The prevalence of ectopic adrenocorticotropic hormone syndrome development was assessed by evaluating adrenocorticotropic hormone expression using immunohistochemistry. Furthermore, 26 patients with olfactory neuroblastomas who developed ectopic adrenocorticotropic hormone syndrome from previous reports were reviewed. Among the 15 patients, three (20%) showed adrenocorticotropic hormone-positive tumor cells at the time of initial surgery, and two (13%) developed ectopic adrenocorticotropic hormone syndrome. The timing of developing ectopic adrenocorticotropic hormone syndrome was 2.5 and 10 years following initial treatment of olfactory neuroblastoma. Based on the literature review, nine patients with recurrent and metastatic olfactory neuroblastoma developed ectopic adrenocorticotropic hormone syndrome after the initial surgery, of whom, three had confirmed disease after developing ectopic adrenocorticotropic hormone syndrome, three developed during disease progression, two developed after receiving chemotherapy, and one developed after undergoing a biopsy. The timing of ectopic adrenocorticotropic hormone syndrome was 2.5-15 years after initial treatment. Our study revealed that acknowledging olfactory neuroblastomas can manifest as ectopic adrenocorticotropic hormone syndrome with a certain low prevalence is crucial. Moreover, our study speculated that tumor stimulation, such as biopsy or chemotherapy, as well as disease progression, could trigger ectopic adrenocorticotropic hormone syndrome onset. Thus, olfactory neuroblastomas can develop into ectopic adrenocorticotropic hormone syndrome, even long after the initial treatment.

Ventriculosubgaleal shunt placement for hydrocephalus in osteogenesis imperfecta with novel compound heterozygous CRTAP variants.

Osteogenesis imperfecta is characterized by frequent fractures, bone deformities, and other systemic symptoms. Severe osteogenesis imperfecta may progress to hydrocephalus; however, treatment strategies for this complication remain unclear. Here, we describe severe osteogenesis imperfecta in an infant with symptomatic hydrocephalus treated with ventriculosubgaleal shunt placement. Targeted next-generation sequencing revealed novel compound heterozygous CRTAP variants, i.e., NM_006371.5, c.241 G > T, p.(Glu81*) and NM_006371.5, c.923-2_932del. We suggest that ventriculosubgaleal shunt placement is an effective and safe treatment for hydrocephalus in patients with severe osteogenesis imperfecta.

Improved endurance capacity of diabetic mice during SGLT2 inhibition: Role of AICARP, an AMPK activator in the soleus.

BACKGROUND: Diabetes is associated with an increased risk of deleterious changes in muscle mass and function or sarcopenia, leading to physical inactivity and worsening glycaemic control. Given the negative energy balance during sodium-glucose cotransporter-2 (SGLT2) inhibition, whether SGLT2 inhibitors affect skeletal muscle mass and function is a matter of concern. However, how SGLT2 inhibition affects the skeletal muscle function in patients with diabetes remains insufficiently explored. We aimed to explore the effects of canagliflozin (CANA), an SGLT2 inhibitor, on skeletal muscles in genetically diabetic db/db mice focusing on the differential responses of oxidative and glycolytic muscles. METHODS: Db/db mice were treated with CANA for 4 weeks. We measured running distance and handgrip strength to assess skeletal muscle function during CANA treatment. At the end of the experiment, we performed a targeted metabolome analysis of the skeletal muscles. RESULTS: CANA treatment improved the reduced endurance capacity, as revealed by running distance in db/db mice (414.9 ± 52.8 vs. 88.7 ± 22.7 m, P < 0.05). Targeted metabolome analysis revealed that 5-aminoimidazole-4-carboxamide-1-ß-D-ribofuranosyl 5'-monophosphate (AICARP), a naturally occurring AMP-activated protein kinase (AMPK) activator, increased in the oxidative soleus muscle (P < 0.05), but not in the glycolytic extensor digitorum longus muscle (P = 0.4376), with increased levels of AMPK phosphorylation (P < 0.01). CONCLUSIONS: This study highlights the potential role of the AICARP/AMPK pathway in oxidative rather than glycolytic skeletal muscles during SGLT2 inhibition, providing novel insights into the mechanism by which SGLT2 inhibitors improve endurance capacity in patients with type 2 diabetes.

Dectin-2 Deficiency Promotes Proinflammatory Cytokine Release From Macrophages and Impairs Insulin Secretion.

Pancreatic islet inflammation plays a crucial role in the etiology of type 2 diabetes (T2D). Macrophages residing in pancreatic islets have emerged as key players in islet inflammation. Macrophages express a plethora of innate immune receptors that bind to environmental and metabolic cues and integrate these signals to trigger an inflammatory response that contributes to the development of islet inflammation. One such receptor, Dectin-2, has been identified within pancreatic islets; however, its role in glucose metabolism remains largely unknown. Here we have demonstrated that mice lacking Dectin-2 exhibit local inflammation within islets, along with impaired insulin secretion and ß-cell dysfunction. Our findings indicate that these effects are mediated by proinflammatory cytokines, such as interleukin (IL)-1α and IL-6, which are secreted by macrophages that have acquired an inflammatory phenotype because of the loss of Dectin-2. This study provides novel insights into the mechanisms underlying the role of Dectin-2 in the development of islet inflammation.

Metal-doped magnetite thin films.

This paper investigates magnetite (Fe3O4) thin film containing a small amount of a metal element. The films are prepared by rf sputtering with a composite target of ceramic iron oxide with metal chips. Low-temperature magnetization of magnetite containing 5.3%Ge reveals that the film contains some magnetically weak coupling grains. The metal element Mg reduces both hematite (alpha-Fe2O3) and magnetite, resulting in single-phase wüstite (Fe1-xO). In contrast, adding Ge selectively reduces hematite, while magnetite remains unreactive. According to the free energy of reaction, the element Ge is able to reduce hematite only, whereas the element Mg is capable of reducing both hematite and magnetite. This property is in good agreement with the experiment results.

Carotid body tumor with neck metastasis due to germline SDHB variant: a case report and literature review.

Carotid body tumor involving the succinate dehydrogenase subunit B (SDHB) variant reportedly had a higher frequency of metastasis than other variants of succinate dehydrogenase. However, the correlation between genotype and phenotype among patients with carotid body tumor with SDHB gene variant remains unclear. Thus, we present a case of carotid body tumor with neck lymph metastasis caused by a novel SDHB variant, which resulted in long-term disease-free survival achieved after surgery. A 43-year-old man presented to our hospital with a 2-year history of a painless neck mass. Based on the radiographic findings, the patient was diagnosed with carotid body tumor with a possible Shamblin type III tumor. Another mass was detected and suspected to be a lymph node metastasis. The patient underwent resection of the tumor and lymph nodes. The common carotid artery, internal carotid artery, external carotid artery, internal jugular vein, vagal nerve, and hypoglossal nerve were resected with the tumor. Histopathological examination revealed a paraganglioma. The histological findings of the lymph nodes were similar to those of the carotid body tumor and were confirmed to be metastases of paraganglioma. To analyze the germline SDHx variant, a nonsense variant was detected in the SDHB gene at exon 2, c. 136C > T, p. Arg46*. During the follow-up 80 months after surgery, the patient exhibited no signs of recurrence, metastasis, or development of paragangliomas in other organs. This was the first case of carotid body tumor accompanied by neck metastasis caused by a germline nonsense SDHB variant at exon 2, c. 136C > T, p. Arg46*. Carotid body tumor with neck lymph metastasis caused by this nonsense variant could achieve long-term disease-free survival after surgery. Gene analysis, including SDHB variant, should be performed to predict the prognosis and future risk of metastasis. Genetic testing of SDHB may give a crucial information for the treatment and follow-up strategies of carotid body tumor. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13691-021-00522-x.

Pretherapeutic Predictive Factors for Histological High-Grade Parotid Gland Carcinoma.

OBJECTIVE: The histological grade of parotid gland carcinoma (PGC) is an important prognostic factor; however, the diagnosis prior to treatment has been challenging to make. This study aimed to investigate whether the pretreatment clinical findings, including hematological inflammatory, nutritional, and immune markers, could predict the histological grade of PGC. STUDY DESIGN: Retrospective study. METHODS: We retrospectively enrolled 111 patients with PGC and evaluated the correlation between histological grade and pretreatment clinical findings such as age, sex, tumor staging, facial nerve paralysis, pain or tenderness, adhesion to the surrounding tissues or tumor immobility, and hematological markers. RESULTS: Sixty patients (54%) were diagnosed with histological high-grade PGC. Univariate analysis revealed that age, T classification, N classification, TNM stage, facial nerve paralysis, adhesion/immobility, C-reactive protein (CRP), and CRP-to-albumin ratio (CAR) were significant predictors of PGC histological grade. On multivariate analysis, high T classification (T3, 4), high N classification (≥1), and elevated CRP (≥0.22 mg/dL) were independent predictors of high-grade PGC. CONCLUSIONS: Pretreatment T classification, N classification, and CRP are significant predictors of the histological grading of PGC. Our results are useful for treatment planning and obtaining appropriate informed consent from the patients before treatment. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:96-102, 2022.

Late neointimal volume reduction is observed following biodegradable polymer-based drug eluting stent in porcine model.

BACKGROUND: The BP-SES has an abluminally applied biodegradable polymer that is fully resorbed after 3-4 months but may have longer-lasting effects. The aim of this study was to determine the long-term vascular response to the novel Ultimaster™ sirolimus-eluting stent (BP-SES). METHODS: BP-SESs, everolimus-eluting stents (DP-EESs), and bare metal stents were implanted in 22 coronary arteries of 15 mini-swine. All animals underwent optical frequent domain imaging (OFDI) to assess neointimal volume and quality at either 1 (n = 7) or 3 (n = 8) months and at 9 (n = 15) months and were euthanized at 9 months. Stents were subsequently histologically investigated to analyze the vascular response and maturity of neointimal tissue according to cell density. RESULTS: OFDI revealed greater regression in neointimal volume from 3 to 9 months with BP-SESs than with DP-EESs (-0.6 ± 0.5 mm2 vs. 0.00 ± 0.4 mm2, p = 0.07). Although there was no significant difference between BP-SESs and DP-EESs in the inflammation score (BMS, BP-SES, and DP-EES: 0.1 ± 0.1, 0.3 ± 0.4, and 0.4 ± 0.4, respectively; p < 0.0001) in histological analysis, BP-SESs showed slightly greater maturity than DP-EESs (1.8 ± 0.3, 1.7 ± 0.3, and 1.6 ± 0.3, p = 0.09). CONCLUSIONS: While both BP-SESs and DP-EESs showed minimal inflammatory responses at 9 months, BP-SESs showed a trend for greater neointimal maturity and regression, which may be related to earlier completion of the vascular response.

Risk factor for cerebrospinal fluid leak after endoscopic endonasal skull base surgery: a single-center experience.

BACKGROUND: One of the major complications in endoscopic endonasal skull base surgery (EESBS) is postoperative cerebrospinal fluid (CSF) leaks. Recently, EESBS has been applied to various skull base diseases as well as more complicated cases influenced by previous treatment with or without various comorbidities. AIMS/OBJECTIVES: This study aimed to assess the factors that influence the results of postoperative CSF leak after EESBS with mixed patient backgrounds. MATERIALS AND METHODS: We conducted a retrospective analysis of the clinical records of patients undergoing EESBS in our institution from 2012 to 2017. RESULTS: Out of a total of 230 cases of EESBS, 11 (4.8%) suffered from postoperative CSF leakage. The rate of CSF leakage for pituitary adenoma, Rathke's cleft cyst, chordoma, and meningioma was 3.5%, 0%, 3.6% and 8.0%, respectively. Multiple variate analysis revealed that repeated surgery (p = .008) and intraoperative CSF leak (p = .044) were significant risk factors for postoperative CSF leakage. CONCLUSIONS AND SIGNIFICANCE: The rate of postoperative CSF leakage in this study was comparable to previous reports, and repeated surgery may increase postoperative CSF leakage. The surgical strategy for tumor removal as well as skull base reconstruction should be given careful consideration according to tumor pathology and the patient's condition.

Prognostic Value of the Lymphocyte-to-Monocyte Ratio in Patients with Parotid Gland Carcinoma.

OBJECTIVE: Previous studies have evaluated various markers as prognostic predictors in patients with many types of cancers. However, the influence of such factors on the outcomes of patients with parotid gland carcinoma (PGC) is unknown. This study investigated the roles of alternative markers in the prognoses of patients with PGC. METHODS: Overall, 101 patients who underwent curative treatment for PGC were retrospectively evaluated, and their 5-year overall and disease-free survival rates were calculated. The prognostic values of clinical and pathologic factors were determined. RESULTS: The 5-year overall and disease-free survival rates were 73.1% and 62.8%, respectively. Multivariate analysis revealed that a low lymphocyte-to-monocyte ratio (LMR), high T classification, high N classification, and perineural invasion were independent predictors of poor prognosis. CONCLUSIONS: Thus, we identified LMR as an independent prognostic factor for patients with PGC. Patients with low LMRs who are amenable to treatment may require adjuvant treatment to improve their prognoses. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E864-E869, 2021.

Liver-specific extracellular matrix hydrogel promotes liver-specific functions of hepatocytes in vitro and survival of transplanted hepatocytes in vivo.

A solubilized liver-specific extracellular matrix (L-ECM) substratum was obtained by decellularization of porcine liver using Triton X-100 and pepsin treatments. The L-ECM was able to immobilize hepatocyte growth factor at a high efficiency of 87%. L-ECM gelled spontaneously in a physiologically neutral environment. Primary hepatocytes embedded in the L-ECM gel showed a high albumin synthesis activity and ethoxyresorufin-O-deethylase (EROD) activity even at 3 weeks in culture. In addition, the L-ECM gel-embedded hepatocytes implanted subcutaneously into partial hepatectomized rats showed a high survival rate (18%) and formed a large liver tissue-like structure. Their efficiencies of EROD activity and large liver tissue-like structure formation were about twice those of collagen gel-embedded hepatocytes. Based on these results, we clarified the effectiveness of L-ECM gel as a substrate for hepatocyte culture and transplantation.

Optimal implantation site of transponders for identification of experimental swine.

Use of transponders, small electronic identification devices, in experimental swine is expected to be more reliable than the current common use of ear tags. However, it is necessary to determine the optimal implantation site for transponders with high readability, retentionability (i.e., long-term retention in tissues without detachment or loss), and biocompatibility, as this has not yet been investigated. Thus, we aimed to determine the optimal implantation site. Two types of transponders were subcutaneously implanted into four different sites (ear base, ear auricle, ventral neck, and back) in 3 domestic swine each. The transponders were scanned at 1, 2, 3, and 84 days after implantation. The location of the transponders was examined by X-ray and echography at 84 days. Histopathological examinations were performed at 84 days. The transponders in the back were successfully scanned in a shorter time than those in other implantation sites, without any re-scanning procedures. X-ray examination revealed one transponder in the ventral neck was lost, whereas those in the other sites were retained in their original location for 84 days. Echography indicated that the transponders in the back were retained more deeply than those in other implantation sites, suggesting better retentionability. Acceptable biocompatibility was confirmed in all implantation sites, as evidenced by the finding that all transponders were covered by a connective tissue capsule without severe inflammation. In conclusion, the present results demonstrated that the back is the optimal implantation site for transponders in experimental swine.

Cyclo-oxygenase-2 Expression Is Associated With Lymph Node Metastasis in Oropharyngeal Squamous Cell Carcinoma Under the New TNM Classification.

BACKGROUND: This study aimed to investigate p16 and COX2 expression in oropharyngeal squamous cell carcinoma (OPSCC), and evaluate the prognostic role of COX2 expression under the new TNM classification. MATERIALS AND METHODS: Biopsy specimens obtained from 75 patients with OPSCC were stained for p16 and COX2 expression immunohistochemically. The results and clinical records were analyzed retrospectively. RESULTS: Fifty-nine patients (79%) were positive for p16. COX2 expression was correlated with poor relapse-free survival in patients overall, and in p16-positive patients. Smoking was positively associated with COX2 expression. Moreover, both positive COX2 expression and anterior wall tumor subsite were independently correlated with lymph node metastasis, which was the only independent prognostic factor in p16-positive OPSCC. CONCLUSION: The p16-positive rate in this study was comparable with that in the USA and Europe, and higher than that in other Asian countries. COX2 expression might affect the prognosis of p16-positive OPSCC through promoting lymph node metastasis.

Binding of MutS protein to oligonucleotides containing a methylated or an ethylated guanine residue, and correlation with mutation frequency.

The MutS-based mismatch repair (MMR) system has been conserved from prokaryotes to humans, and plays important roles in maintaining the high fidelity of genomic DNA. MutS protein recognizes several different types of modified base pairs, including methylated guanine-containing base pairs. Here, we looked at the relationship between recognition and the effects of methylating versus ethylating agents on mutagenesis, using a MutS-deficient strain of E. coli. We find that while methylating agents induce mutations more effectively in a MutS-deficient strain than in wild-type, this genetic background does not affect mutagenicity by ethylating agents. Thus, the role of E. coli MMR with methylation-induced mutagenesis appears to be greater than ethylation-induced mutagenesis. To further understand this difference an early step of repair was examined with these alkylating agents. A comparison of binding affinities of MutS with O(6)-alkylated guanine base paired with thymine, which could lead to transition mutations, versus cytosine which could not, was tested. Moreover, we compared binding of MutS to oligoduplexes containing different base pairs; namely, O(6)-MeG:T, O(6)-MeG:C, O(6)-EtG:T, O(6)-EtG:C, G:T and G:C. Dissociation constants (K(d)), which reflect the strength of binding, followed the order G:T->O(6)-MeG:T->O(6)-EtG:T-=O(6)-EtG:C-> or =O(6)-MeG:C->G:C. These results suggest that a thymine base paired with O(6)-methyl guanine is specifically recognized by MutS and therefore should be removed more efficiently than a thymine opposite O(6)-ethylated guanine. Taken together, the data suggest that in E. coli, the MMR system plays a more significant role in repair of methylation-induced lesions than those caused by ethylation.