Long‐term subjective tongue function after partial glossectomy

There have been limited studies of subjective tongue function over long‐term follow‐up in spite of swallowing and articulation disorders are common complications of glossectomy. To assess long‐term subjective swallowing and articulation function after partial glossectomy. A total of 63 patients with the mobile tongue cancer who underwent partial glossectomy without reconstruction were interviewed to score their swallowing and articulation function on a 100‐point scale. The relation of this subjective scoring to the perioperative data was subjected to multivariate analysis. The mean patient age was 53·4 (19–81) years, and the mean follow‐up duration was 78·9 (14–277) months. Mean swallowing and articulation function score was 87·7 ± 6·1 and 88·6 ± 5·4. Age, follow‐up duration, T stage and resection volume were significantly correlated with swallowing function (P = 0·026, 0·029, 0·016, 0·002, respectively); follow‐up duration was correlated with articulation function (P = 0·039). Patients who undergo partial glossectomy without reconstruction generally demonstrate good function on long‐term follow‐up. Subjective dysfunction was correlated with larger resection volume, older age and shorter follow‐up duration.     

Sex differences in knee strength deficit 1?year after anterior cruciate ligament reconstruction

[Purpose] Little is known about the outcome differences between men and women after anterior cruciate ligament (ACL) reconstruction. Therefore, the present study aimed to compare knee muscle strength between men and women 1 year after ACL reconstruction. [Subjects and Methods] Retrospective and outcome study. Between 2012 and 2015, 35 males (mean age, 29.7 ± 010.7 years) and 35 females (mean age, 28.2 ± 11.3 years) who had undergone primary ACL reconstruction were recruited from Samsung medical centers. We assessed the strength deficit in the quadriceps (extensor) and hamstrings (flexor) at 60°/sec and 180°/sec with isokinetic testing equipment. Statistical analysis was conducted with a t-test to determine if sex differences existed in knee strength deficit. [Results] Significant differences were noted between men and women with respect to extensor muscle strength deficit. Women reported less extensor muscle strength than men did, at the angular velocities 60°/sec and 180°/sec. However, no significant sex differences were found at either velocity with respect to the strength deficit of the knee flexor muscles. [Conclusion] Compared to male patients, female patients reported significantly less extensor muscle strength and less improvement 1 year after reconstruction.Key words: Anterior cruciate ligament, Sex, Female     

Structural and biochemical basis for the inhibition of cell death by APIP,a methionine salvage enzyme

APIP, Apaf-1 interacting protein, has been known to inhibit two main types of programmed cell death, apoptosis and pyroptosis, and was recently found to be associated with cancers and inflammatory diseases. Distinct from its inhibitory role in cell death, APIP was also shown to act as a 5-methylthioribulose-1-phosphate dehydratase, or MtnB, in the methionine salvage pathway. Here we report the structural and enzymatic characterization of human APIP as an MtnB enzyme with a K_m of 9.32 μM and a V_max of 1.39 μmol min⁻¹ mg⁻¹. The crystal structure was determined at 2.0-Å resolution, revealing an overall fold similar to members of the zinc-dependent class II aldolase family. APIP/MtnB exists as a tetramer in solution and exhibits an assembly with C4 symmetry in the crystal lattice. The pocket-shaped active site is located at the end of a long cleft between two adjacent subunits. We propose an enzymatic reaction mechanism involving Glu139* as a catalytic acid/base, as supported by enzymatic assay, substrate-docking study, and sequence conservation analysis. We explored the relationship between two distinct functions of APIP/MtnB, cell death inhibition, and methionine salvage, by measuring the ability of enzymatic mutants to inhibit cell death, and determined that APIP/MtnB functions as a cell death inhibitor independently of its MtnB enzyme activity for apoptosis induced by either hypoxia or etoposide, but dependently for caspase-1-induced pyroptosis. Our results establish the structural and biochemical groundwork for future mechanistic studies of the role of APIP/MtnB in modulating cell death and inflammation and in the development of related diseases.The programmed death of dangerous cells, either infected or transformed, has critical importance for the survival of the multicellular organism and therefore is also of great medical relevance. APIP, Apaf-1 interacting protein, was initially identified as an inhibitor of apoptotic cell death induced by hypoxia/ischemia and cytotoxic drugs (1). Recently APIP was also shown to inhibit pyroptosis, an inflammatory form of cell death, induced by Salmonella infection (2). Thus, APIP has been implicated in two major types of programmed cell death: apoptosis and pyroptosis. In apoptosis, APIP inhibits the mitochondrial pathway involving caspase-9 but not the receptor pathway involving caspase-8 (1, 3). In pyroptosis, APIP’s inhibitory function was recently revealed in a functional genetic screen for the SNP associated with increased caspase-1–mediated cell death in response to Salmonella infection (2) and subsequently confirmed by cell viability assays (2, 4). Intriguingly, other SNPs near APIP were found in patients suffering from systemic inflammatory response syndrome (2), which further implicates APIP in inflammation.Distinct from its inhibitory role in the programmed cell death, APIP was recently shown to act as an enzyme in the methionine salvage pathway (2, 4). The amino acid sequence of human APIP exhibits 23–26% identity to the previously characterized Bacillus and yeast 5-methylthioribulose-1-phosphate dehydratase (MtnB) (4). The methionine salvage pathway converts MTA (5-methylthioadenosine) to methionine through six enzymatic reaction steps, and MtnB is the third enzyme in the pathway and catalyzes the dehydration of MTRu-1-P (5-methylthioribulose-1-phosphate) to DK-MTP-1-P (2,3-diketo-5-methylthiopentyl-1-phosphate) (Fig. 1B) (4, 5). In the absence of methionine, cells supplemented with MTA exhibit decreased viability when APIP expression is reduced (2, 4). These studies indicate that APIP is an MtnB enzyme in the methionine salvage pathway.Open in a separate windowFig. 1.APIP as an MtnB enzyme in the methionine salvage pathway. (A) Initial reaction rate was plotted at seven different concentrations of the substrate MTRu-1-P for Michaelis-Menten kinetic analysis. Data represent mean values with SE from three independent measurements. (B) Methionine salvage pathway characterized in Homo sapiens and Saccharomyces cerevisiae converts MTA to methionine (Met) through the common six enzymatic reactions. Dashed line represents B. subtilis methionine salvage reaction steps distinct from H. sapiens and S. cerevisiae. Gray colored enzymatic steps and metabolites represent biochemical links that are not conceptually part of the methionine salvage pathway. AdoMet, S-adenosyl-l-methionine; dAdoMet, decarboxylated AdoMet; DHK-MTPene, 1,2-dihydroxy-3-keto-5-methylthiopentene; HK-MTPenyl-1-P, 2-hydroxy-3-keto-5-methylthiopentenyl-1-phosphate; Met, l-methionine; MTOB, 4-methylthio-2-oxobutyrate; MTR, 5-methylthioribose.The methionine salvage pathway is found in all organisms, from bacteria to plants and animals (6). The role of this pathway is to recycle MTA, which is a by-product of the polyamine synthetic process, back to methionine (Fig. 1B). The methionine salvage pathway is beneficial as a means of recycling the sulfur present in MTA because assimilation of sulfur is thermodynamically costly (6). The metabolic importance of the pathway is underscored in humans because methionine is one of the essential amino acids needed to be provided through the diet, in which it is one of the most limiting amino acids (6). Recently, the methionine salvage pathway attracted medical interest because it was implicated in cell death and inflammation and diseases associated with these processes. For example, metabolites such as MTA and 2-keto-4-methylthiobutyrate (KMTB) have effects of apoptosis induction (6–9). MTA was also shown to induce caspase-1–dependent pyroptosis in the inflammatory response to bacterial infection (2). In addition, the 5-methylthioadenosine phosphorylase (MTAP, which catalyzes the first step) is a tumor suppressor implicated in a various human cancers (6, 10), and aci-reducton dioxygenase 1 (ADI1, also called MtnD, which catalyzes the fifth step) has a similar role in prostate cancer (11, 12). Human APIP/MtnB, which is the focus of the present study, is another example of a methionine salvage enzyme that is implicated in cell death and inflammation. APIP/MtnB was recently reported to be up-regulated in squamous carcinoma cells from tongue and larynx (13) and down-regulated in the cells and tumors of non–small-cell lung carcinoma (14). In addition, APIP/MtnB is implicated in inflammatory conditions that likely involve caspase-1–dependent pyroptosis, such as systemic inflammatory response syndrome (2).Studies of APIP/MtnB to date have focused mainly on its functional role either in cell death or in methionine salvage. To gain a better understanding of APIP/MtnB at a molecular and biochemical level, we carried out a structural and biochemical characterization in this study. The MtnB enzyme activity of APIP was verified by an in vitro enzyme assay. In addition, the crystal structure was determined at 2.0-Å resolution, which revealed details of the active site architecture and led to a proposed catalytic mechanism. Furthermore, we explored the relationship between two distinct functions of APIP/MtnB, cell death inhibition, and methionine salvage, by testing its enzymatic mutants derived from the crystal structure for their ability to inhibit two main types of programmed cell death: pyroptosis and apoptosis.     

Gastric Choristoma of the Oropharynx

Heterotopic gastric mucosa tissue is also called gastric choristoma, and this type of lesion can be found anywhere in the alimentary tract. However, gastric choristoma in the pharynx is very rare; only 10 cases of pharyngeal gastric choristoma have been reported in the English medical literature. A 32-yr-old woman was referred to our institution for the evaluation of a large mass that originated from the posterior wall of the oropharynx. The mass did not cause any symptoms except for the occasional sensation of a foreign body. Gadolinium-enhanced T1 weighted imaging showed a 5 cm-sized mass with central enhancement and hypointense portions, yet the radiological diagnosis was not clear. Transoral mass excision was performed with using electrocautery for making the diagnosis and for treating the mass. The microscopic analysis revealed gastric choristoma.     

Zinc tetrakis(N-methyl-4'-pyridyl) porphyrinato is an effective inhibitor of stimulant-induced activation of RAW 264.7 cells

One proposed mechanism for the development of silica-induced fibrosis is prolonged pulmonary inflammation and lung damage resulting from the secretion of reactive mediators from alveolar macrophages. Metalloporphyrins have antioxidative and antiinflammatory activities. However, the molecular basis for the antiinflammatory action of zinc tetrakis(N-methyl-4'-pyridyl) porphyrinato (ZnTMPyP) has not been elucidated. The objective of this study was to determine whether ZnTMPyP exhibited the ability to inhibit the production of reactive oxygen species (ROS), the activation of NF-kappaB, or the secretion of IL-1 in RAW 264.7 cells, and whether such inhibitory activity was related to the ROS-scavenging ability of ZnTMPyP. The results indicate that, although ZnTMPyP is not cytotoxic to RAW 264.7 cells, it is a potent inhibitor in ROS production by RAW 264.7 cells in response to various stimulants, such as silica, zymosan, or phorbol myristate acetate. ZnTMPyP is also effective in reducing stimulant-induced DNA-binding activity of NF-kappaB and silica-induced tyrosine phosphorylation of IkappaB-alpha. ZnTMPyP also inhibits LPS-induced IL-1 production. However, ZnTMPyP exhibits relatively weak ability to directly scavenge hyroxyl or superoxide radicals. On the basis of effective concentrations of ZnTMPyP, these results suggest that ZnTMPyP directly acts as an inhibitor of cellular activation in addition to exhibiting an antioxidant effect. Therefore, it is suggested that further studies concerning the effects of ZnTMPyP using in vivo oxidative stress models or its effects on the cytotoxic process of human diseases associated with lung inflammation and injury are warranted. In addition, ZnTMPyP may be a useful tool to investigate the molecular mechanisms involved in stimulant-induced signal pathways.