Corrigendum: Ankle-Brachial Index Is Independently Associated With Cardiovascular Outcomes and Foot Ulcers in Asian Patients With Type 2 Diabetes Mellitus.

[This corrects the article DOI: 10.3389/fendo.2021.752995.].

Ankle-Brachial Index Is Independently Associated With Cardiovascular Outcomes and Foot Ulcers in Asian Patients With Type 2 Diabetes Mellitus.

Background and Aims: The ankle-brachial index (ABI) is an efficient tool for objectively documenting the presence of lower-extremity peripheral arterial disease (PAD). The predictive factors of cardiovascular events and diabetic foot ulcer were not clear from the ABI examination in Taiwanese patients with type 2 diabetes mellitus (DM). Methods: We enrolled 482 patients with type 2 DM who regularly visited the outpatient department of Chang Gung Memorial Hospital and received ABI as well as brachial-ankle pulse wave velocity (ba-PWV) examinations from 2010 to 2017. Age, gender, PAD symptoms, comorbidities, family history of chronic diseases, lifestyle (smoking, alcohol consumption, and exercise), height, weight, waist circumference, monofilament testing and foot ulcer status were studied. Results: There were 104 (22%) patients (mean age, 67.8 years) with the ABI <1.0. These patients with low ABI (ABI<1.0) had a significantly older age (p=0.001), higher delta PWV (p<0.001), higher rates of stroke (p=0.007), myocardial infarction (p=0.016), and foot ulcer (p=0.039). In a multivariable analysis model, the adjusted odds ratio (aOR) for myocardial infarction, stroke, and foot ulcers associated with low ABI were 1.219 (0.397-3.743, p=0.729), 1.204 (0.556-2.610, p=0.638), and 2.712 (1.199-6.133, p=0.017), respectively. The patients with low PWV (PWV<1400 cm/s) were significantly younger (p<0.001) and had a lower rate of hypertension (p<0.001), and higher percentages of stroke (p=0.027) and dialysis (p=0.041) family history. Conclusions: Low ABI was associated with cardiovascular events and diabetic foot ulcer independently in patients with type 2 DM.

Needlescopic-assisted thoracoscopic pulmonary anatomical lobectomy and segmentectomy for lung cancer: a bridge between multiportal and uniportal thoracoscopic surgery.

PURPOSE: Needlescopic instruments allow us to perform complex laparoscopic procedures, which are almost painless and scarless postoperatively; however, their utilization in thoracoscopic surgery has been limited to minor procedures, including bullectomy and sympathectomy. We present our initial experience of performing thoracoscopic anatomical lung resection via a single utility incision with additional needlescopic working ports and compare the operative results with those of uniportal video-assisted thorascopic surgery (VATS). METHODS: We reviewed data on 75 consecutive patients with lung cancer, who underwent anatomical lung resections, including lobectomy and segmentectomy, between February 2015 and September 2017. Of the 75 patients, 39 underwent uniportal VATS (uniportal group), and 36 underwent needlescopic-assisted VATS (n-VATS group). We compared the peri- and postoperative outcomes of the two groups. RESULTS: The clinical characteristics did not differ significantly between the groups, except in the ages of the patients. The n-VATS group had a shorter operation time (mean 159.3 min vs. 198.8 min, P = 0.023) and lower intraoperative blood loss (mean 40.9 mL vs. 143.2 mL, P = 0.047). Two major pulmonary arterial bleeding events and one conversion to thoracotomy occurred in the uniportal group. CONCLUSION: Uniportal VATS can be performed more efficiently and safely with the assistance of additional needlescopic ports and instruments, without compromising the benefits of less postoperative pain and early recovery.

Crystal structure of an antigenic outer-membrane protein from Salmonella Typhi suggests a potential antigenic loop and an efflux mechanism.

ST50, an outer-membrane component of the multi-drug efflux system from Salmonella enterica serovar Typhi, is an obligatory diagnostic antigen for typhoid fever. ST50 is an excellent and unique diagnostic antigen with 95% specificity and 90% sensitivity and is used in the commercial diagnosis test kit (TYPHIDOT(TM)). The crystal structure of ST50 at a resolution of 2.98 Å reveals a trimer that forms an α-helical tunnel and a ß-barrel transmembrane channel traversing the periplasmic space and outer membrane. Structural investigations suggest significant conformational variations in the extracellular loop regions, especially extracellular loop 2. This is the location of the most plausible antibody-binding domain that could be used to target the design of new antigenic epitopes for the development of better diagnostics or drugs for the treatment of typhoid fever. A molecule of the detergent n-octyl-ß-D-glucoside is observed in the D-cage, which comprises three sets of Asp361 and Asp371 residues at the periplasmic entrance. These structural insights suggest a possible substrate transport mechanism in which the substrate first binds at the periplasmic entrance of ST50 and subsequently, via iris-like structural movements to open the periplasmic end, penetrates the periplasmic domain for efflux pumping of molecules, including poisonous metabolites or xenobiotics, for excretion outside the pathogen.

Ribose-5-phosphate isomerase A regulates hepatocarcinogenesis via PP2A and ERK signaling.

The deregulated nonoxidative pentose phosphate pathway (PPP) is known to promote oncogenesis, but the molecular mechanism remains unknown. Here, we report that human ribose-5-phosphate isomerase A (RPIA) plays a role in human hepatocellular carcinoma (HCC). A significant increase in RPIA expression was detected both in tumor biopsies of HCC patients and in a liver cancer tissue array. Importantly, the clinicopathological analysis indicated that RPIA mRNA levels were highly correlated with clinical stage, grade, tumor size, types, invasion and alpha-fetoprotein levels in the HCC patients. In addition, we demonstrated that the ability of RPIA to regulate cell proliferation and colony formation in different liver cancer cell lines required ERK signaling as well as the negative modulation of PP2A activity and that the effects of RPIA could be modulated by the addition of either a PP2A inhibitor or activator. Furthermore, the xenograft studies in nude mice revealed that the modulation of RPIA in liver cancer cells regulated tumor growth and that NIH3T3 cells overexpressing RPIA exhibited increased proliferation, enhanced colony formation, elevated levels of p-ERK1/2 and accelerated tumor growth. This study provides new insight into the molecular mechanisms by which RPIA overexpression can induce oncogenesis in HCC. Furthermore, it suggests that RPIA can be a good prognosis biomarker and a potential target for HCC therapy.

Single domain antibody against carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) inhibits proliferation, migration, invasion and angiogenesis of pancreatic cancer cells.

Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) is over-expressed in pancreatic cancer cells, and it is associated with the progression of pancreatic cancer. We tested a single domain antibody (sdAb) targeting CEACAM6, 2A3, which was isolated previously from a llama immune library, and an Fc conjugated version of this sdAb, to determine how they affect the pancreatic cancer cell line BxPC3. We also compared the effects of the antibodies to gemcitabine. Gemcitabine and 2A3 slowed down cancer cell proliferation. However, only 2A3 retarded cancer cell invasion, angiogenesis within the cancer mass and BxPC3 cell MMP-9 activity, three features important for tumour growth and metastasis. The IC50s for 2A3, 2A3-Fc and gemcitabine were determined as 6.5µM, 8µM and 12nM, respectively. While the 2A3 antibody inhibited MMP-9 activity by 33% compared to non-treated control cells, gemcitabine failed to inhibit MMP-9 activity. Moreover, 2A3 and 2A3-Fc inhibited invasion of BxPC3 by 73% compared to non-treated cells. When conditioned media that were produced using 2A3- or 2A3-Fc-treated BxPC3 cells were used in a capillary formation assay, the capillary length was reduced by 21% and 49%, respectively. Therefore 2A3 is an ideal candidate for treating tumours that over-express CEACAM6.

Haemoglobin-induced oxidative stress is associated with both endogenous peroxidase activity and H2O2 generation from polyunsaturated fatty acids.

Patients with increased haemolytic haemoglobin (Hb) have 10-20-times greater incidence of cardiovascular mortality. The objective of this study was to evaluate the role of Hb peroxidase activity in LDL oxidation. The role of Hb in lipid peroxidation, H(2)O(2) generation and intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) was assessed using NaN(3), a peroxidase inhibitor, catalase, a H(2)O(2) decomposing enzyme and human umbilical vein endothelial cells (HUVECs), respectively. Hb induced H(2)O(2) production by reacting with LDL, linoleate and cell membrane lipid extracts. Hb-induced LDL oxidation was inhibited by NaN(3) and catalase. Furthermore, Hb stimulated ICAM-1 and VCAM-1 expression, which was inhibited by the antioxidant, probucol. Thus, the present study suggests that the peroxidase activity of Hb produces atherogenic, oxidized LDL and oxidized polyunsaturated fatty acids (PUFAs) in the cell membrane and reactive oxygen species (ROS) formation mediated Hb-induced ICAM-1 and VCAM-1 expression.

Evidence for beta-lactoglobulin involvement in vitamin D transport in vivo--role of the gamma-turn (Leu-Pro-Met) of beta-lactoglobulin in vitamin D binding.

Beta-lactoglobulin (LG) is a major bovine milk protein, containing a central calyx and a second exosite beyond the calyx to bind vitamin D; however, the biological function of LG in transporting vitamin D remains elusive. Crystallographic findings from our previous study showed the exosite to be located at the pocket between the alpha-helix and beta-strand I. In the present study, using site-directed mutagenesis, we demonstrate that residues Leu143, Pro144 and Met145 in the gamma-turn loop play a crucial role in the binding. Further evidence is provided by the ability of vitamin D(3) to block the binding of a specific mAb in the gamma-turn loop. Using the mouse (n = 95) as an animal model, we initially demonstrated that LG is a major fraction of milk proteins responsible for uptake of vitamin D. Most interestingly, dosing mice with LG supplemented with vitamin D(3) revealed that native LG containing two binding sites gave a saturated concentration of plasma 25-hydroxyvitamin D at a dose ratio of 2 : 1 (vitamin D(3)/LG), whereas heated LG containing one exosite (lacking a central calyx) gave a ratio of 1 : 1. We have demonstrated for the first time that LG has a functional advantage in the transport of vitamin D, indicating that supplementing milk with vitamin D effectively enhances its uptake.

A unique tetrameric structure of deer plasma haptoglobin--an evolutionary advantage in the Hp 2-2 phenotype with homogeneous structure.

Similar to blood types, human plasma haptoglobin (Hp) is classified into three phenotypes: Hp 1-1, 2-1 and 2-2. They are genetically inherited from two alleles Hp 1 and Hp 2 (represented in bold), but only the Hp 1-1 phenotype is found in almost all animal species. The Hp 2-2 protein consists of complicated large polymers cross-linked by alpha2-beta subunits or (alpha2-beta)n (where n>or=3, up to 12 or more), and is associated with the risk of the development of diabetic, cardiovascular and inflammatory diseases. In the present study, we found that deer plasma Hp mimics human Hp 2, containing a tandem repeat over the alpha-chain based on our cloned cDNA sequence. Interestingly, the isolated deer Hp is homogeneous and tetrameric, i.e. (alpha-beta)4, although the locations of -SH groups (responsible for the formation of polymers) are exactly identical to that of human. Denaturation of deer Hp using 6 m urea under reducing conditions (143 mmbeta-mercaptoethanol), followed by renaturation, sustained the formation of (alpha-beta)4, suggesting that the Hp tetramers are not randomly assembled. Interestingly, an alpha-chain monoclonal antibody (W1), known to recognize both human and deer alpha-chains, only binds to intact human Hp polymers, but not to deer Hp tetramers. This implies that the epitope of the deer alpha-chain is no longer exposed on the surface when Hp tetramers are formed. We propose that steric hindrance plays a major role in determining the polymeric formation in human and deer polymers. Phylogenetic and immunochemical analyses revealed that the Hp 2 allele of deer might have arisen at least 25 million years ago. A mechanism involved in forming Hp tetramers is proposed and discussed, and the possibility is raised that the evolved tetrameric structure of deer Hp might confer a physiological advantage.

Crystal structure of a secondary vitamin D3 binding site of milk beta-lactoglobulin.

Beta-lactoglobulin (beta-LG), one of the most investigated proteins, is a major bovine milk protein with a predominantly beta structure. The structural function of the only alpha-helix with three turns at the C-terminus is unknown. Vitamin D(3) binds to the central calyx formed by the beta-strands. Whether there are two vitamin D binding-sites in each beta-LG molecule has been a subject of controversy. Here, we report a second vitamin D(3) binding site identified by synchrotron X-ray diffraction (at 2.4 A resolution). In the central calyx binding mode, the aliphatic tail of vitamin D(3) clearly inserts into the binding cavity, where the 3-OH group of vitamin D(3) binds externally. The electron density map suggests that the 3-OH group interacts with the carbonyl of Lys-60 forming a hydrogen bond (2.97 A). The second binding site, however, is near the surface at the C-terminus (residues 136-149) containing part of an alpha-helix and a beta-strand I with 17.91 A in length, while the span of vitamin D(3) is about 12.51 A. A remarkable feature of the second exosite is that it combines an amphipathic alpha-helix providing nonpolar residues (Phe-136, Ala-139, and Leu-140) and a beta-strand providing a nonpolar (Ile-147) and a buried polar residue (Arg-148). They are linked by a hydrophobic loop (Ala-142, Leu-143, Pro-144, and Met-145). Thus, the binding pocket furnishes strong hydrophobic force to stabilize vitamin D(3) binding. This finding provides a new insight into the interaction between vitamin D(3) and beta-LG, in which the exosite may provide another route for the transport of vitamin D(3) in vitamin D(3) fortified dairy products. Atomic coordinates for the crystal structure of beta-LG-vitamin D(3) complex described in this work have been deposited in the PDB (access code 2GJ5).

Identification of a new single-nucleotide mutation on the hypoxanthine-guanine phosphoribosyltransferase gene from 983 cases with gout in Taiwan.

OBJECTIVE: The frequency of hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency within the gout-affected population in Taiwan was unclear. We evaluated its frequency and sought to identify a new genetic variation in a case with HPRT deficiency. METHODS: From 2004 to 2005, a total of 983 patients with gout were followed among outpatients attending the Department of Rheumatology. Among these, 12 cases were suspected to have HPRT deficiency, and HPRT activity was examined by HPLC. In the index case found to have HPRT deficiency, genetic variation was analyzed by RT-PCR, direct sequencing, and SSCP. RESULTS: Only a single case proved to have partial HPRT deficiency among 12 suspicious cases. Both cDNA and genomic DNA analysis identified a new mutation on exon 2 with T to G transition at cDNA base 93, resulting in a change from aspartic acid to glutamic acid at position 31. It was designated as HPRTChia-Yi, from our case's residence at Chia-Yi Hsein, Taiwan. CONCLUSION: According to this hospital-based survey, HPRT deficiency is a rare trait in the Taiwanese gouty population. However, our index case with HPRT deficiency provided the first proven HPRT mutation in non-aboriginal Taiwanese patients with gout, which was different from a mutation previously found in aboriginal Taiwanese. Hence, in non-aboriginal Taiwanese gouty patients with HPRT deficiency, exon 2, rather than just exon 3, should be analyzed.

Epitope mapping of a monoclonal antibody specific to bovine dry milk: involvement of residues 66-76 of strand D in thermal denatured beta-lactoglobulin.

beta-Lactoglobulin (beta-LG) is a bovine milk protein sensitive to thermal denaturation. Previously, we demonstrated that such structural change can be detected by a monoclonal antibody (mAb) specific to denatured beta-LG. In the present study, we show a dramatic increase in beta-LG immunoreactivity when heating raw milk between 70 and 80 degrees C. To map out the specific epitope of beta-LG recognized by this mAb, we used a combined strategy including tryptic and CNBr fragments, chemical modifications (acetylation and carboxymethylation), peptide array containing in situ synthesized peptides, and a synthetic soluble peptide for immunoassays. The antigenic determinant we defined was exactly located within the D strand (residues 66-76) of beta-LG. Circular dichroic spectral analysis shows that carboxymethylation on beta-LG not only resulted in a substantial loss of beta-configuration but also exerted a 10 times increase in immunoreactivity as compared with heated beta-LG. The result suggests that a further disordered structure occurred in beta-LG and thus rendered the mAb recognition. Mutations on each charged residue (three Lys and one Glu) revealed that Lys-69 and Glu-74 were extremely essential in maintaining the antigenic structure. We also show an inverse relationship between the immunoreactivity in heated beta-LG and its binding to retinol or palmitic acid. Most interestingly, pH 9-10, which neutralizes the Lys groups of beta-LG, not only reduced its immunoreactivity but also its binding to palmitic acid implicating a role of Lys-69. Taken together, we concluded that strand D of beta-LG participated in the thermal denaturation between 70 and 80 degrees C and the binding to retinol and palmitic acid. The antigenic and biochemical roles of mAb specific to D strand are discussed in detail.

Expression of hBUB1 in acute myeloid leukemia.

hBUB1 gene is a component of the mitotic checkpoint that monitors proper assembly of the mitotic spindles and the alteration of the hBUB1 gene has been found to be associated with chromosomal instability in some tumor cell lines. We analyzed the coding region of the hBUB1 gene for mutations and its expression in 92 acute myeloid leukemia (AML) specimens and five hematopoietic cell lines. We also used Southern hybridization to analyze the genomic DNA of those cases, which had aberrant transcription to confirm the lesion. A thymine/cytosine polymorphism at 8 bp upstream of the 5' splice acceptor site of exon 10 was observed in Raji cell line and two AML specimens without a resultant change in the expression of hBUB1. Reduced expression and aberrant transcription of the hBUB1 gene, which may affect the control of mitotic checkpoint, were detected in AML specimens by reverse transcription-polymerase chain reaction (RT-PCR) analysis. Our study suggests that the mutation of the hBUB1 gene is a rare event in AML, and further studies are necessary to clarify its role in leukemia.