Current Status of Clinical Diagnosis and Genetic Analysis of Hereditary Hemorrhagic Telangiectasia in South Korea: Multicenter Case Series and a Systematic Review

Purpose Hereditary hemorrhagic telangiectasia (HHT), a rare genetic vascular disorder, has been rarely reported in South Korea. We investigated the current prevalence and presenting patterns of genetically confirmed HHT in South Korea. Materials and Methods We defined HHT patients as those with proven mutations on known HHT-related genes (ENG, ACVRL1, SMAD4, and GDF2) or those fulfilling 3 or 4 of the Curaçao criteria. A computerized systematic search was performed in PubMed and KoreaMed using the following search term: (“hereditary hemorrhagic telangiectasia” AND “Korea”) OR (“Osler-Weber-Rendu” AND “Korea”). We also collected government health insurance data. HHT genetic testing results were collected from three tertiary hospitals in which the genetic tests were performed. We integrated patient data by analyzing each case to obtain the prevalence and presenting pattern of HHT in South Korea. Results We extracted 90 cases from 52 relevant articles from PubMed and KoreaMed. An additional 22 cases were identified from the three Korean tertiary hospitals after excluding seven cases that overlapped with those in the published articles. Finally, 112 HHT patients were identified (41 males and 71 females, aged 4–82 years [mean±standard deviation, 45.3±20.6 years]). The prevalence of HHT in South Korea is about 1 in 500,000, with an almost equal prevalence among men and women. Forty-nine patients underwent genetic testing, of whom 28 had HHT1 (ENG mutation) and 19 had HHT2 (ACVRL1 mutation); the other two patients were negative for ENG, ACVRL1, and SMAD4 mutations. Conclusion The prevalence of HHT is underestimated in Korea. The rate of phenotypic presentation seems to be similar to that found worldwide. Korean health insurance coverage is limited to representative genetic analysis to detect ENG and ACVRL1 mutations. Further genetic analyses to detect HHT3, HHT4, and other forms of HHT should be implemented

A case of emphysematous hepatitis with spontaneous pneumoperitoneum in a patient with hilar cholangiocarcinoma

An 80-year-old woman with hilar cholangiocarcinoma was hospitalized due to sudden-onset abdominal pain. Computed tomography revealed hepatic necrosis accompanied with emphysematous change in the superior segment of the right liver (S7/S8), implying spontaneous rupture, based on the presence of perihepatic free air. Although urgent percutaneous drainage was performed, neither pus nor fluids were drained. These findings suggest emphysematous hepatitis with a hepatic mass. Despite the application of intensive care, the patient's condition deteriorated rapidly, and she died 3 days after admission to hospital. Liver gas has been reported in some clinical diseases (e.g., liver abscess) to be caused by gas-forming organisms; however, emphysematous hepatitis simulating emphysematous pyelonephritis is very rare. The case reported here was of fatal emphysematous hepatitis in a patient with hilar cholangiocarcinoma

Development of Nitrogen-15- and Carbon-13-Labeled Biochemical Probes for Hyperpolarized Metabolic Imaging

Pages 44-75 are misnumbered as pages 43-74, pages 76-103 are misnumbered as pages 73-100, pages 104-129 are misnumbered as pages 100-125, and pages 130-134 are misnumbered as pages 125-129.13C and 15N dynamic nuclear polarization coupled with nuclear magnetic resonance study provides an opportunity to non-invasively monitor metabolic fluxes in vivo using appropriately designed 13C or 15N enriched metabolic probes. However, hyperpolarized spin states have a short lifetime because the hyperpolarized magnetization decays by T1 relaxation. This restricts the biological applications of hyperpolarized probes. Therefore, the goal of this dissertation work is to develop 13C and 15N enriched probes with long T1 values that quickly enter cells and actively metabolize or act as reporters of important biological metal ions involved in metabolism. The first project focuses on cell permeable 15N labeled hyperpolarized probes designed to report zinc levels, which play a crucial role in the onset and progression of prostate cancer. Deuterated 15N-tris(pyridylmethyl)amine designed and synthesized for this purpose was found to have extremely long T1 values and an altered 15N chemical shift upon Zn2+ binding. Its applicability for zinc mapping was demonstrated in hyperpolarized 15N MRI experiments in phantoms. The second project was to demonstrate the feasibility of using hyperpolarized [1-13C]ketoisocaproic acid as an imaging agent to detect altered branched-chain amino acid metabolism in glioma. This probe was successfully used to monitor both branched-chain aminotransferase and alpha-keto acid dehydrogenase activity in glioma by hyperpolarized 13C imaging in vivo. Both 13C- ketoisocaproic acid in vivo imaging and 13C-leucine infusion study provided strong evidence for increased catabolism of ketoisocaproic acid in tumor compared to the contralateral normal appearing brain tissue. The third project involved the design and synthesis of 13C labeled glyoxylate in an attempt to image the glyoxylate shunt pathways. [1-13C]Glyoxylate hydrate was successfully synthesized and was evaluated as a metabolic probe for the glyoxylate cycle in cells. However, the incorporation of [1-13C]glyoxylate via the glyoxylate cycle was not observed in the mouse embryonic fibroblasts and yeast cells. This is likely due to the high chemical reactivity of glyoxylate toward free amino groups of proteins. In summary, in these projects, 15N and 13C labeled hyperpolarized probes have been investigated for noninvasive monitoring of physiochemical sensing and metabolic processes, which could provide a key to detect abnormality of cancer metabolism

Albumin-binding PARACEST Agents

Lanthanide complexes (Eu3+, Gd3+ and Yb3+) of two different 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid tetraamide derivatives containing two (2) and four (3) O-benzyl-L-serine amide substituents were synthesized and their chemical exchange saturation transfer (CEST) and relaxometric properties were examined in the presence and absence of human serum albumin (HSA). Both Eu2 and Eu3 display a significant CEST effect from a single slowly exchanging Eu3+-bound water molecule, making these PARACEST complexes potentially useful as vascular MRI agents. Yb2 also showed a detectable CEST effect from both the Yb3+-bound water protons and the exchangeable NH amide protons, making it potentially useful as a vascular pH sensor. Fluorescence displacement studies using reporter molecules indicate that both Gd2 and Gd3 displace dansylsarcosine from site II of HSA with inhibition constants of 32 and 96 μM, respectively, but neither complex significantly displaces warfarin from site I. Water proton relaxation enhancements of 135 and 171% were observed upon binding of Gd2 and Gd3 to HSA, respectively, at 298 K and pH 7.4

Stilbene Vinyl Sulfonamides as Fluorogenic Sensors of and Traceless Covalent Kinetic Stabilizers of Transthyretin That Prevent Amyloidogenesis

Small molecules that react selectively with a specific non-enzyme drug-target protein in a complex biological environment without displacement of a leaving group (tracelessly) are rare and highly desirable. Herein we describe the development of a family of fluorogenic stilbene-based vinyl amides and vinyl sulfonamides that covalently modify transthyretin (TTR) tracelessly. These small molecules bind selectively to TTR in complex biological environments and then undergo a rapid and chemoselective 1,4-Michael addition with the p<i>K</i>_a-perturbed Lys-15 ε-amino group of TTR. Replacing the vinyl amide in <b>2</b> with the more reactive vinyl sulfonamide in <b>4</b> hastens the conjugation kinetics. X-ray cocrystallography verified the formation of the secondary amine bond mediating the conjugation in the case of <b>2</b> and <b>4</b> and confirmed the expected orientation of the stilbene within the TTR binding sites. Vinyl amide <b>2</b> and vinyl sulfonamide <b>4</b> potently inhibit TTR dissociation and amyloid fibril formation in vitro. The TTR binding selectivity, modification yield, and reaction chemoselectivity of vinyl sulfonamide <b>4</b> are good enough in human plasma to serve as a starting point for medicinal chemistry efforts. Moreover, vinyl sulfonamide <b>4</b> is fluorogenic: it exhibits minimal background fluorescence in complex biological environments, remains dark upon binding to TTR, and becomes fluorescent only upon reaction with TTR. The fluorogenicity of <b>4</b> was utilized to accurately quantify the native TTR concentration in Escherichia coli lysate using a fluorescence plate reader

In Vivo ZIMIR Imaging of Mouse Pancreatic Islet Cells Shows Oscillatory Insulin Secretion

Appropriate insulin secretion is essential for maintaining euglycemia, and impairment or loss of insulin release represents a causal event leading to diabetes. There have been extensive efforts of studying insulin secretion and its regulation using a variety of biological preparations, yet it remains challenging to monitor the dynamics of insulin secretion at the cellular level in the intact pancreas of living animals, where islet cells are supplied with physiological blood circulation and oxygenation, nerve innervation, and tissue support of surrounding exocrine cells. Herein we presented our pilot efforts of ZIMIR imaging in pancreatic islet cells in a living mouse. The imaging tracked insulin/Zn2+ release of individual islet beta-cells in the intact pancreas with high spatiotemporal resolution, revealing a rhythmic secretion activity that appeared to be synchronized among islet beta-cells. To facilitate probe delivery to islet cells, we also developed a chemogenetic approach by expressing the HaloTag protein on the cell surface. Finally, we demonstrated the application of a fluorescent granule zinc indicator, ZIGIR, as a selective and efficient islet cell marker in living animals through systemic delivery. We expect future optimization and integration of these approaches would enable longitudinal tracking of beta cell mass and function in vivo by optical imaging