Development of Novel Focal Irradiation Tool for High-Precision Irradiation Using Clinical Brachytherapy System

PURPOSE/OBJECTIVE(S)

Several small animals, including mice, are used to conduct research on state-of-the-art radiation therapy techniques or treatment-related toxicity. However, it is difficult to conduct the focal irradiation to a shallow depth on small animals, because irradiation using LINAC has limitations in energy and field size. The purpose of this paper was to develop a focal irradiation tool for high-precision irradiation and to evaluate beam characteristics.

MATERIALS/METHODS

We designed the collimator of 1 mm diameter consisting of tungsten material for high-precision irradiation applied to the clinical brachytherapy system and the percent depth dose and horizontal profile were measured. We compared the depth dose and horizontal profile with 4 mm diameter SRS cone for 6 MV in LINAC. We measured the PDD and horizontal profile using EBT3 film for high-precision irradiation of 1 mm diameter using Ir-192 source. In case of 4 mm diameter, the beam was measured using edge detector. In addition, all measurements were compared with the results of planning tool simulation.

RESULTS

In case of focal irradiation tool, the maximum dose showed at the surface for both measurement and simulation, and 26% and 32% doses at 1 mm depth, respectively. In addition, FWHM at a 1 mm depth showed that high-precision irradiation was possible with measurement and simulation results of 1.86 and 1.28 mm. In case of LINAC, the maximum dose was showed at a depth of 1 cm and 0.8 cm in the measurement and simulation, respectively. Even if the smallest cone is used, the FWHM at a dmax depth was 4.0 mm in both simulation and measurement.

CONCLUSION

We overcame the limitation for energy and field size through the focal irradiation tool for high-precision irradiation. The focal irradiation tool enables high dose delivery to the shallow depth. In addition, small FWHM reduced dose delivery to the periphery at a specific depth and enabled accurate dose delivery. These results mean that the focal irradiation tool can be useful in small animal experiments that require accurate doses near the shallow depth.

First Report of Pseudomonas cichorii Causing Bacterial vein necrosis on Perilla plants [Perilla frutescens (L.) Britton.] in South Korea

Perilla (Perilla frutescens L.) is the second most important upland crop and the third largest edible oil crop in Korea (Shin and Kim 1994). During a disease survey in Busan, Korea in September 2021, symptoms of vein necrosis were observed in perilla plants, with incidences of approximately 30% and 50% in two fields. Symptoms of spots on the perilla appeared as leaf dryness and spots with water-soaked blotches largely concentrated on the mid-veins of leaves. The lesions were initiated with water-soaked spots on the leaf or stem and gradually turned black or brown. Necrosis was also observed in the stems. A bacterium was isolated on Luria-Bertani (LB) agar from diseased leaf tissues that were surface-disinfected with 70% ethyl alcohol for 3-5 min and then washed with sterile water three times. Three pieces of sterilized leaf tissue (size: 0.5 × 0.5 cm) were mixed with 500 µL sterile water for 30 min, and then the suspension was serially diluted and spread on LB agar. Subsequently, isolates were cultivated on LB agar and King's Medium B agar (KMB) (Schaad et al. 2001), and they were predominantly cream-colored and circular bacterial colonies with undulated margins. The bacterial colonies on KMB displayed fluorescence under 365 nm UV light. The isolates were analyzed with the GEN III MicroPlate (Biolog, Hayward, CA, USA), and all isolates were identified as Pseudomonas cichorii, a devastating plant bacterium that damages a wide range of host plants worldwide, including in South Korea (Hikichi et al. 2013; Ramkumar et al. 2015). To identify the species of the bacterial pathogen, genomic DNA of four isolates (BS4922, BS4167, BS4345, and BS4560) was extracted, and the 16S rRNA gene and hrcRST gene were amplified with universal primers, 27F/1492R and Hcr1/Hcr2, and sequencing was then done (Patel et al. 2019). In the BLAST analysis, the 16S rRNA sequences (GenBank OM060656, OM275434, OM275435, OM275436) showed a 100% and 99% similarity to P. cichorii strains MAFF 302698 (AB724286) and P. cichorii strain Pc-Gd-4 (KU923373), respectively. Further, hrcRST gene sequences (GenBank OM143596, OM268864, OM268865, and OM268866) showed high similarity (>99%) with P. cichorii strain P16-51 (MG518230). A pathogenicity test of the four isolates was performed on 3 - 4 weeks old perilla plants by creating wounds with a needle on the lower leaves and stems, and then the plants were inoculated by spraying inoculum (108 CFU/ml). The plants that served as the negative control were wounded and sprayed with unsterilized water. The inoculated perilla plants were placed in a greenhouse at 28 ± 2oC , 80-85% relative humidity, and a natural photoperiod. The inoculation site began to show symptoms of water-soaked brown lesions. Disease symptoms such as leaf dryness, water-soaked blotches on the mid-vein of leaves, and necrosis on plant stems were observed in the inoculated plants 7-10 days after inoculation, whereas the plants of the negative control group did not show any symptoms. The bacteria were re-isolated from the diseased tissues of the plants, and DNA sequence analysis identified them as P. cichorii. Additionally, all isolates induced hypersensitivity reactions in tobacco and tomato leaves within 24 h after inoculation. To our knowledge, this is the first report of P. cichorii infecting perilla in South Korea. The findings in this study will provide the basic information for the development of diagnostic tools and management measures against P. cichorii in perilla.

Targeted attenuation of elevated histone marks at SNCA alleviates α-synuclein in Parkinson's disease

Epigenetic deregulation of α-synuclein plays a key role in Parkinson's disease (PD). Analysis of the SNCA promoter using the ENCODE database revealed the presence of important histone post-translational modifications (PTMs) including transcription-promoting marks, H3K4me3 and H3K27ac, and repressive mark, H3K27me3. We investigated these histone marks in post-mortem brains of controls and PD patients and observed that only H3K4me3 was significantly elevated at the SNCA promoter of the substantia nigra (SN) of PD patients both in punch biopsy and in NeuN-positive neuronal nuclei samples. To understand the importance of H3K4me3 in regulation of α-synuclein, we developed CRISPR/dCas9-based locus-specific H3K4me3 demethylating system where the catalytic domain of JARID1A was recruited to the SNCA promoter. This CRISPR/dCas9 SunTag-JARID1A significantly reduced H3K4me3 at SNCA promoter and concomitantly decreased α-synuclein both in the neuronal cell line SH-SY5Y and idiopathic PD-iPSC derived dopaminergic neurons. In sum, this study indicates that α-synuclein expression in PD is controlled by SNCA's histone PTMs and modulation of the histone landscape of SNCA can reduce α-synuclein expression.

Neurodevelopmental defects and neurodegenerative phenotypes in human brain organoids carrying Parkinson's disease-linked DNAJC6 mutations

Loss-of-function mutations of DNAJC6, encoding HSP40 auxilin, have recently been identified in patients with early-onset Parkinson's disease (PD). To study the roles of DNAJC6 in PD pathogenesis, we used human embryonic stem cells with CRISPR-Cas9-mediated gene editing. Here, we show that DNAJC6 mutations cause key PD pathologic features, i.e., midbrain-type dopamine (mDA) neuron degeneration, pathologic α-synuclein aggregation, increase of intrinsic neuronal firing frequency, and mitochondrial and lysosomal dysfunctions in human midbrain-like organoids (hMLOs). In addition, neurodevelopmental defects were also manifested in hMLOs carrying the mutations. Transcriptomic analyses followed by experimental validation revealed that defects in DNAJC6-mediated endocytosis impair the WNT-LMX1A signal during the mDA neuron development. Furthermore, reduced LMX1A expression during development caused the generation of vulnerable mDA neurons with the pathologic manifestations. These results suggest that the human model of DNAJC6-PD recapitulates disease phenotypes and reveals mechanisms underlying disease pathology, providing a platform for assessing therapeutic interventions.

Simple guidelines for evaluating intraoperative alignment after the reduction of intertrochanteric fractures

The incidence of intertrochanteric femoral fractures has rapidly increased with the extended lifespan of the elderly population. Surgery enables early ambulation by achieving anatomic reduction and stable internal fixation. However, reduction usually involves postoperative evaluation. Here, we present reliable parameters obtained from analyses of three-dimensional computed tomography images from cadavers to serve as guidelines during the reduction of intertrochanteric fractures. We included 184 three-dimensional modeling samples from cadavers placed in two standardized positions, similar to C-arm imaging. We recorded the level of the orthogonal line from the greater trochanter (GT) tip to the femoral head (GT orthogonal line [GTOL]) in the anteroposterior view and the line along the anterior femoral cortex passing through the femoral head (anterior cortical line) in the axial view. Correlations between these lines and angular alignments were statistically determined. The GTOL passed above the femoral head center at mean 2.36 mm in all patients; 77.17% of such instances were in the upper second quadrant of the femoral head. The anterior cortical line passed under the femoral head center at mean 10.82 mm; 73.37% of such instances were in the inferior one-third of the femoral head. Consistent correlations were found between the GTOL and neck-shaft angle and between the anterior cortical line and anteversion. The GTOL and anterior cortical line passed through a constant level of the femoral head in most samples and were correlated with angular alignments. The intraoperative use of these simple imaginary lines improves the intertrochanteric fracture reduction quality.

Omega-3 Fatty Acid-Type Docosahexaenoic Acid Protects against Aβ-Mediated Mitochondrial Deficits and Pathomechanisms in Alzheimer's Disease-Related Animal Model

It has been reported that damage to the mitochondria affects the progression of Alzheimer's disease (AD), and that mitochondrial dysfunction is improved by omega-3. However, no animal or cell model studies have confirmed whether omega-3 inhibits AD pathology related to mitochondria deficits. In this study, we aimed to (1) identify mitigating effects of endogenous omega-3 on mitochondrial deficits and AD pathology induced by amyloid beta (Aβ) in fat-1 mice, a transgenic omega-3 polyunsaturated fatty acids (PUFAs)-producing animal; (2) identify if docosahexaenoic acid (DHA) improves mitochondrial deficits induced by Aβ in HT22 cells; and (3) verify improvement effects of DHA administration on mitochondrial deficits and AD pathology in B6SJL-Tg(APPSwFlLon,PSEN1*M146L*L286V)6799Vas/Mmjax (5XFAD), a transgenic Aβ-overexpressing model. We found that omega-3 PUFAs significantly improved Aβ-induced mitochondrial pathology in fat-1 mice. In addition, our in vitro and in vivo findings demonstrate that DHA attenuated AD-associated pathologies, such as mitochondrial impairment, Aβ accumulation, neuroinflammation, neuronal loss, and impairment of adult hippocampal neurogenesis.

Pharmacological Stimulation of Nurr1 Promotes Cell Cycle Progression in Adult Hippocampal Neural Stem Cells

Nuclear receptor related-1 (Nurr1) protein performs a crucial role in hippocampal neural stem cell (hNSC) development as well as cognitive functions. We previously demonstrated that the pharmacological stimulation of Nurr1 by amodiaquine (AQ) promotes spatial memory by enhancing adult hippocampal neurogenesis. However, the role of Nurr1 in the cell cycle regulation of the adult hippocampus has not been investigated. This study aimed to examine changes in the cell cycle-related molecules involved in adult hippocampal neurogenesis induced by Nurr1 pharmacological stimulation. Fluorescence-activated cell sorting (FACS) analysis showed that AQ improved the progression of cell cycle from G0/G1 to S phase in a dose-dependent manner, and MEK1 or PI3K inhibitors attenuated this progression. In addition, AQ treatment increased the expression of cell proliferation markers MCM5 and PCNA, and transcription factor E2F1. Furthermore, pharmacological stimulation of Nurr1 by AQ increased the expression levels of positive cell cycle regulators such as cyclin A and cyclin-dependent kinases (CDK) 2. In contrast, levels of CDK inhibitors p27KIP1 and p57KIP2 were reduced upon treatment with AQ. Similar to the in vitro results, RT-qPCR analysis of AQ-administered mice brains revealed an increase in the levels of markers of cell cycle progression, PCNA, MCM5, and Cdc25a. Finally, AQ administration resulted in decreased p27KIP1 and increased CDK2 levels in the dentate gyrus of the mouse hippocampus, as quantified immunohistochemically. Our results demonstrate that the pharmacological stimulation of Nurr1 in adult hNSCs by AQ promotes the cell cycle by modulating cell cycle-related molecules.

LIN28A loss of function is associated with Parkinson's disease pathogenesis

Parkinson's disease (PD) is neurodegenerative movement disorder characterized by degeneration of midbrain-type dopamine (mDA) neurons in the substantia nigra (SN). The RNA-binding protein Lin28 plays a role in neuronal stem cell development and neuronal differentiation. In this study, we reveal that Lin28 conditional knockout (cKO) mice show degeneration of mDA neurons in the SN, as well as PD-related behavioral deficits. We identify a loss-of-function variant of LIN28A (R192G substitution) in two early-onset PD patients. Using an isogenic human embryonic stem cell (hESC)/human induced pluripotent stem cell (hiPSC)-based disease model, we find that the Lin28 R192G variant leads to developmental defects and PD-related phenotypes in mDA neuronal cells that can be rescued by expression of wild-type Lin28A. Cell transplantation experiments in PD model rats show that correction of the LIN28A variant in the donor patient (pt)-hiPSCs leads to improved behavioral phenotypes. Our data link LIN28A to PD pathogenesis and suggest future personalized medicine targeting this variant in patients.

Ghrelin in Alzheimer's disease: Pathologic roles and therapeutic implications

Ghrelin, which has many important physiological roles, such as stimulating food intake, regulating energy homeostasis, and releasing insulin, has recently been studied for its roles in a diverse range of neurological disorders. Despite the several functions of ghrelin in the central nervous system, whether it works as a therapeutic agent for neurological dysfunction has been unclear. Altered levels and various roles of ghrelin have been reported in Alzheimer's disease (AD), which is characterized by the accumulation of misfolded proteins resulting in synaptic loss and cognitive decline. Interestingly, treatment with ghrelin or with the agonist of ghrelin receptor showed attenuation in several cases of AD-related pathology. These findings suggest the potential therapeutic implications of ghrelin in the pathogenesis of AD. In the present review, we summarized the roles of ghrelin in AD pathogenesis, amyloid beta (Aβ) homeostasis, tau hyperphosphorylation, neuroinflammation, mitochondrial deficit, synaptic dysfunction and cognitive impairment. The findings from this review suggest that ghrelin has a novel therapeutic potential for AD treatment. Thus, rigorously designed studies are needed to establish an effective AD-modifying strategy.

Magnetic Resonance Colonography Enables the Efficacy Assessment of Immune Checkpoint Inhibitors in an Orthotopic Colorectal Cancer Mouse Model

Immune checkpoint inhibitors (ICIs) have become an effective therapeutic option for colorectal cancer and studies on these drugs have therefore increased greatly. Efficacy assessments of ICIs in preclinical orthotopic colorectal cancer using MRI have not been reported however due to the difficulties in conducting colorectal imaging. The purpose of this present study was to investigate the feasibility of using magnetic resonance colonography (MRC) to evaluate the efficacy of an ICI, an anti-PD-L1 antibody, in an orthotopic colorectal cancer mouse model. The mouse model was generated by the engraftment of colorectal cancer cells into the submucosal layer of the colon. Anti-cancer efficacy was assessed by tumor volume and metastatic tumor number analyses, and these values were significantly lower in the PD-L1 antibody-treated group compared to the controls. Histological analyses using H&E and Ki-67 immunohistochemical staining confirmed a highly efficacious tumor growth inhibition and enhanced infiltration by CD4+ and CD8+ lymphocytes in the PD-L1 antibody-treated group. We conclude that MRC has the potential to be used for ICI efficacy assessments against orthotopic colorectal cancer mouse model.

Antibiotic coated hinged threaded rods in the treatment of infected nonunions and intramedullary long bone infections

INTRODUCTION

Local delivery of high dose antibiotics in the form of antibiotic impregnated polymethyl methacrylate (PMMA) cement beads or coated rods is commonly used in the management of long bone infections. The downsides of antibiotic cement beads for intramedullary long bone infections are associated with difficulty in removal from the medullary canal, bead breakage, and lack of stability. Antibiotic cement-coated smooth flexible guide wires, rods and nails can have complications such as delamination or debonding of the cement. In addition, the current techniques for cement rod insertion have a risk of iatrogenic joint contamination. To improve upon this technique and decrease potential complications, we propose the use of an antibiotic cement-coated hinged threaded rod as a temporary intramedullary spacer. This technique utilizes both an antegrade and retrograde insertion of the threaded rod into the medullary canal through the bony defect site with connection at the hinge to treat intramedullary long bone infections and infected nonunions.

MATERIAL AND METHODS

A total of 40 patients were included in the study. The details in making the cement rod were well documented. The shape of cement rod and the integrity of the cement at the time of rod insertion and rod removal were compared to identify any cement debonding or delamination. Potential postoperative complications including iatrogenic joint infection, displacement or breakage of the threaded cement rods, and fracture displacement were all carefully documented. The preliminary biological effect of the initial debridement and antibiotic cement rod placement was determined using the negative conversion rate of intraoperative cultures.

RESULTS

A single antibiotic coated threaded rod was inserted in 18 cases. Two separate antibiotic coated threaded rods were inserted and connected via hinge in 22 cases. There were zero cases of rod breakage and no secondary loss of reduction from antibiotic rod placement to the definitive staged operation. There were zero iatrogenic joint infections. There were zero cases of cement debonding or delamination from the rod. The conversion rate to a negative culture after initial debridement and antibiotic rod placement was 85% (34/40 cases).

CONCLUSIONS

The use of an antibiotic coated cement threaded rod with a hinge as an intramedullary spacer provides the benefits of local antibiotic delivery, offers improved construct stability, makes implant removal easier without delamination of the cement mantle, and utilizes the versatility of a hinge to prevent violation of native joints when treating infected nonunions and intramedullary long bone infections.

Kidney Transplantation Using Expanded-Criteria Deceased Donors: A Comparison With Ideal Deceased Donors and Non-Expanded-Criteria Deceased Donors

PURPOSE

The use of expanded-criteria deceased-donor (ECD) kidneys must be evaluated within the objective perspective of critical organ shortage and graft function and survival. In this study, we aimed to compare the clinical outcomes of ECD reliance with concurrent use of ideal-criteria deceased donors (IDDs) and non-ECDs in adult renal transplantation.

METHODS

Between February 2000 and December 2015, we analyzed 405 deceased-donor renal transplants, specifically 129 grafts (31.9%) from ECDs, 233 grafts (57.5%) from non-ECDs, and 43 grafts (10.6%) from IDDs. ECDs were classified according to the United Network for Organ Sharing guidelines, while an IDD was defined as a younger person (10-39 years of age) with no medical risk factors who died from a traumatic head injury. Donor and recipient risk factors were separately analyzed and correlated with recipient graft function, and survival was evaluated.

RESULTS

ECDs were older (56.8 ± 6.3 years); showed increased incidence of hypertension, diabetes, and cerebrovascular brain death; and had a higher pre-retrieval serum creatinine level than the other groups. ECD kidney recipients were also older (50.6 ± 9.8 years), had a shorter waiting time (P = .031), and demonstrated a low frequency of re-transplantation (P = .028). Long-term renal function followed longitudinally was lower in ECD kidney recipients until five years after transplantation, while the glomerular filtration rate (GFR) level at 7 and 10 years did not differ significantly among the groups (P = .074 and .262, respectively). There were no significant differences in terms of graft survival (P = .394) or patient survival (P = .737) among the groups.

CONCLUSIONS

Although the long-term renal function followed longitudinally was lower in ECD kidney recipients, the use of renal grafts from ECDs is an acceptable method to resolve the disparity of critical organ shortage. However, the classification of the high-risk group should be updated with consideration given to differences in regional characteristics.

Comminuted inferior pole fracture of patella can be successfully treated with rim-plate-augmented separate vertical wiring

INTRODUCTION

We present the surgical technique of rim-plate-augmented separate vertical wiring for comminuted inferior pole fracture of the patella and report the clinical outcomes.

MATERIALS AND METHODS

Between July 2013 and January 2016, 13 patients (7 male and 6 female) who were diagnosed with comminuted inferior pole fracture of the patella in preoperative computed tomography and underwent a minimum of 1 year of follow-up were enrolled in this study. Mean patient age was 57.7 years (range 28-72 years). All patients underwent open reduction and internal fixation by rim-plate-augmented separate vertical wiring. Bony union, complications, range of motion and Bostman score were the clinical outcomes.

RESULTS

Bony union was achieved in all cases at an average of 10 weeks after surgery (range 8-12). There was no loss of reduction and fixative failure during follow-up. The average range of motion was 127° (range 120°-130°). The mean Bostman score at last follow-up was 29.6 points (range 27-30) and graded excellent in 12 patients.

CONCLUSION

Rim-plate-augmented separate vertical wiring demonstrated secure fixation and favorable clinical outcomes. This study provides evidence for its effectiveness as a fixation method for treating displaced, comminuted inferior pole fracture of the patella.

Progression of Osteoporosis After Kidney Transplantation in Patients With End-Stage Renal Disease

BACKGROUND

This study investigated the prevalence of osteoporosis and the risk factors for its progression in kidney transplant recipients (KTRs).

METHODS

Dual energy X-ray absorptiometry was used to prospectively measure changes in bone mineral density (BMD) before kidney transplantation (KT) and 1 year after transplantation in 207 individuals. We also analyzed the risk factors of osteoporosis progression during this period.

RESULTS

Prior to KT, the mean BMD score (T-score of the femur neck area) was -2.1 ± 1.2, and the prevalence of osteoporosis was 41.5% (86/207). At 1 year post-transplantation, the mean BMD score significantly decreased to -2.3 ± 1.1 (P < .001), and the prevalence of osteoporosis increased to 47.3% (98/207; P = .277). The BMD score worsened over the study period in 69.1% (143/207) of patients, improved in 24.1% (50/207), and showed no change in 6.8% (14/207). Minimal intact parathyroid hormone (iPTH) improvement after KT was found to be an independent risk factor of osteoporosis progression.

CONCLUSIONS

This study demonstrates progressive loss of BMD after KT and sustained secondary hyperparathyroidism might influence the progression of osteoporosis.

Influencing factors on CPAP adherence and anatomic characteristics of upper airway in OSA subjects

Although continuous positive airway pressure (CPAP) is the most effective treatment modality, poor adherence still remains a problem for obstructive sleep apnea (OSA) treatment and there is little evidence regarding how this might be improved. This study aims to analyze the anatomic and clinical factors of OSA subjects who failed to comply with CPAP therapy.The medical records of 47 OSA subjects who received CPAP therapy as a first-line treatment modality were retrospectively reviewed. The medical records were reviewed for demographic and polysomnographic data and anatomic findings of the nasal cavity and oropharynx.24 patients who adhered to CPAP therapy and 23 patients who were nonadherent were enrolled in the study. There were no statistically significant differences in sleep parameters between CPAP-adherent patients and CPAP nonadherent subjects. Mean body mass index of CPAP nonadherent group was significantly higher than CPAP adherent group. Higher grades of septal deviation and hypertrophic change of the inferior turbinate were observed more in the CPAP nonadherent group. In addition, CPAP nonadherent subjects showed considerably bigger tonsils and higher grade palatal position comparing with the CPAP adherent subjects. Subjective discomfort including inconvenience, mouth dryness, and chest discomfort were the main problems for OSA subjects who did not comply with CPAP therapy.Excessive upper airway blockage in the nasal cavity and oropharynx was predominant in CPAP nonadherent subjects, which might cause the reported subjective discomfort that reduces CPAP compliance. Therefore, resolution of these issues is needed to enhance CPAP compliance for control of OSA.

The administration of hydrogen sulphide prior to ischemic reperfusion has neuroprotective effects in an acute stroke model

Emerging evidence has suggested that hydrogen sulfide (H₂S) may alleviate the cellular damage associated with cerebral ischemia/reperfusion (I/R) injury. In this study, we assessed using ¹H-magnetic resonance imaging/magnetic resonance spectroscopy (¹H-MRI/MRS) and histologic analysis whether H₂S administration prior to reperfusion has neuroprotective effects. We also evaluated for differences in the effects of H₂S treatment at 2 time points. ¹H-MRI/MRS data were obtained at baseline, and at 3, 9, and 24 h after ischemia from 4 groups: sham, control (I/R injury), sodium hydrosulfide (NaHS)-30 and NaHS-1 (NaHS delivery at 30 and 1 min before reperfusion, respectively). The total infarct volume and the midline shift at 24 h post-ischemia were lowest in the NaHS-1, followed by the NaHS-30 and control groups. Peri-infarct volume was significantly lower in the NaHS-1 compared to NaHS-30 and control animals. The relative apparent diffusion coefficient (ADC) in the peri-infarct region showed that the NaHS-1 group had significantly lower values compared to the NaHS-30 and control animals and that NaHS-1 rats showed significantly higher relative T2 values in the peri-infarct region compared to the controls. The relative ADC value, relative T2 value, levels of N-acetyl-L-aspartate (NAA), and the NAA, glutamate, and taurine combination score (NGT) in the ischemic core region at 24 h post-ischemia did not differ significantly between the 2 NaHS groups and the control except that the NAA and NGT values were higher in the peri-infarct region of the NaHS-1 animals at 9 h post-ischemia. In the ischemic core and peri-infarct regions, the apoptosis rate was lowest in the NaHS-1 group, followed by the NaHS-30 and control groups. Our results suggest that H₂S treatment has neuroprotective effects on the peri-infarct region during the evolution of I/R injury. Furthermore, our findings indicate that the administration of H₂S immediately prior to reperfusion produces the highest neuroprotective effects.

Circumferential bone grafting around an absorbable gelatin sponge core reduced the amount of grafted bone in the induced membrane technique for critical-size defects of long bones

OBJECTIVES

The objectives of the study were to introduce a circumferential bone graft around an absorbable gelatin sponge core using an induced membrane technique, to assess its ability to reduce the required amount of graft and to maintain the bone graft, and to evaluate the clinical outcomes in the management of critical-size bone defects.

PATIENTS AND METHODS

Circumferential bone grafting using a staged induced membrane technique for managing critical-size bone defects was performed in 21 patients. Postoperative computed tomography scans were performed 7days after Hemovac drain removal and 3 months after bone grafting. Volumetric measurements of the defect size, gelatin sponge proportion, and amount of grafted bone were performed by two independent observers using three-dimensional (3D) software.

RESULTS

The critical-size defects were located at the metadiaphyseal area of 11 tibias, eight femurs, and two humeri. The average defect size was 8.9cm in length and 65.2cm³ in volume. The absorbable gelatin sponge core replaced 21.4% (average) of the defect volume. There was no significant deterioration in the shape of the grafted bone among the serial 3D models. Eighteen patients (86%) were healed radiographically at 9.1 months (average).

CONCLUSION

Our study suggests that circumferential bone grafting in association with the induced membrane technique could reduce the required amount of bone graft and adequately maintain graft position and shape, with favourable clinical outcomes.

Enhanced efficacy of radiofrequency ablation for hepatocellular carcinoma using a novel vascular disrupting agent, CKD-516

BACKGROUND

CKD-516 is a novel vascular disrupting agent that shuts down intratumoral blood flow. We therefore hypothesized that concomitant administration of CKD-516 would enhance the therapeutic efficacy of radiofrequency ablation (RFA) by reducing heat sink effects. We assessed the effects of the combination of CKD-516 and RFA in a rat orthotopic hepatocellular carcinoma (HCC) model.

METHODS

Rat HCC cells (N1-S1) were engrafted into the hepatic lobe of Sprague-Dawley (SD) rats. Mice were randomly divided into two groups: RFA-only and CKD-RFA. In the CKD-RFA group, CKD-516 was administered by intraperitoneal injection 2 h before RFA. Ablation zone size was measured on triphenyltetrazolium chloride-stained specimens. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was performed to evaluate the area of apoptosis/necrosis in the ablation zone. Immunohistochemistry with anti-CD31 antibody was performed to evaluate the effect of CKD-516 on tumor vessels.

RESULTS

Ablation zone size was significantly larger in the CKD-RFA group than in the RFA-only group (243.10 ± 74.39 versus 123.30 ± 28.17 mm², p < 0.001). On TUNEL staining, the area of apoptosis/necrosis was also significantly larger in the CKD-RFA group than in the RFA-only group (274.44 ± 140.78 versus 143.74 ± 90.13 mm²; p = 0.006). Immunohistochemistry with anti-CD31 antibody revealed patent tumor vessels in the RFA-only group, while collapsed vessels were seen in the CKD-RFA group, indicating a vascular shutdown effect of CKD-516.

CONCLUSION

Concomitant administration of CKD-516 during RFA can increase the ablation zone of tumors due to its vascular disrupting effect.

Experiences of Living Donors for Small Bowel Transplantation

INTRODUCTION

Along with developments in surgical and immunosuppression techniques, the success rate of small bowel transplantation has increased. In Korea, the incidence of small bowel transplantations has increased, and the longest surviving living donor recipient has now survived for over 12 years postsurgery. The purpose of this study was to assess the experiences of living donors for small bowel transplantation before, during, and after the transplantation.

METHODS

In one hospital, we conducted interviews, based on open-ended questions, with three small bowel donors. We asked them about experiences during small bowel donation. The living donor's statements were analyzed using interpretive phenomenological analysis.

RESULTS

Donors decided to donate because they felt "sorry for the suffering of a family member" and they had "faith in the medical staff." In the early phase after donation, living donors experienced physical changes in their body, including pain, fatigue, altered bowel habits, and abdominal discomfort. Despite temporary limitations in daily and social activities, support from family members allowed the donors to fully recover and return to normal physical, social, and psychological status. The donors mentioned they experienced love and support from their family, as well as satisfaction and pride from donation, during the entire process.

CONCLUSION

We hope that the physical, psychological, and social experience of living donors during small bowel transplantation deduced in this study will serve as a foundation for the establishment of an intervention method to provide education before donation and help recovery after donation.

Regulatory B Cell-Dependent Islet Transplant Tolerance Is Also Natural Killer Cell Dependent

Immunologic tolerance to solid organ and islet cell grafts has been achieved in various rodent models by using antibodies directed at CD45RB and Tim-1. We have shown that this form of tolerance depends on regulatory B cells (Bregs). To elucidate further the mechanism by which Bregs induce tolerance, we investigated the requirement of natural killer (NK) and NKT cells in this model. To do so, hyperglycemic B6, μMT, Beige, or CD1d^-/- mice received BALB/c islet grafts and treatment with the tolerance-inducing regimen consisting of anti-CD45RB and anti-TIM1. B6 mice depleted of both NK and NKT cells by anti-NK1.1 antibody and mice deficient in NK activity (Beige) did not develop tolerance after dual-antibody treatment. In contrast, transplant tolerance induction was successful in CD1d^-/- recipients (deficient in NKT cells), indicating that NK, but not NKT, cells are essential in B cell-dependent tolerance. In addition, reconstitution of Beige host with NK cells restored the ability to induce transplant tolerance with dual-antibody treatment. Transfer of tolerance by B cells from tolerant mice was also dependent on host Nk1.1⁺ cells. In conclusion, these results show that regulatory function of B cells is dependent on NK cells in this model of transplantation tolerance.

Measurement of altered APP isoform expression in adipose tissue of diet-induced obese mice by absolute quantitative real-time PCR

Obesity is associated with increased risk of Alzheimer’s disease. Previous studies have demonstrated that amyloid-beta precursor protein (APP) is expressed in subcutaneous adipose tissue (SAT), upregulated with obesity, and correlates with insulin resistance and adipose tissue inflammation. APP is alternatively spliced into several isoforms, which may be indicative of the pathogenesis of APP-related diseases, but the accurate quantification has been difficult to standardize and reproduce. In light of this, we developed isoform-specific absolute cDNA standards for absolute quantitative real-time PCR (AQ-PCR), and measured transcript copy numbers for three major APP isoforms (APP770, APP751, and APP695), in SAT from C57BL/6 mice fed either a normal or high-fat diet. Expression of all three major APP isoforms was increased in diet-induced obese mice. Transcript copy numbers of APP770 and APP695 correlated with plasma insulin and CCL2 gene expression. The ratios of APP770 and APP751 to APP695 gradually decreased with aging, and correlated with plasma glucose levels. In addition, APP770 was significantly decreased in thiazolidinedione-treated mice. We describe quantification of APP isoform transcripts by AQ-PCR, which allows for direct comparison of gene copy number across isoforms, between experiments, and across studies conducted by independent research groups, which relative quantitative PCR does not allow. Our results suggest a possible role of differential expression of APP isoforms in the development of obesity-related insulin resistance and adipose tissue inflammation. In addition, it is important to determine if altered ratios of APP isoforms in SAT contribute to higher circulating Aβ peptides and increased risk of abnormalities in obesity.

Ten-Year Experience With Bowel Transplantation at Seoul St. Mary's Hospital

A retrospective review of intestinal transplantation (ITx) at Seoul St. Mary's Hospital was made by collecting clinical data over the past 10 years. Fifteen consecutive cases from 2004 were analyzed. Five children and 10 adults (6 months to 69 years of age) were included. Primary diseases in adults included 4 mesenteric vessel thromboses, 2 strangulations, and 1 each of visceral myopathy, malignant gastrointestinal stromal tumor (GIST), mesenteric lymphangiectasis, and injury. Pediatric cases involved 2 Hirschsprung disease, 2 visceral myopathy, and 1 necrotizing enterocolitis. Three of 7 stomas were closed using a serial transverse enteroplasty procedure before transplantation. The ITx were performed using 3 living-donor Itx, 12 deceased-donor ITx, 14 isolated Itx, and 1 modified multivisceral transplantation. Daclizumab, basiliximab, alemtusumab, or basiliximab with rabbit antithymocyte globulin (rATG) was used for the induction; tacrolimus monotherapy was used as the basic maintenance immunosuppressant; and m-TOR inhibitor was used for renal dysfunction patients. Seven cases of acute cellular rejection were treated with rATG. Three cases of antibody-mediated rejection were treated with rituximab alone or with rituximab and bortezomib combination. There were 4 cases of early mortality within 6 months after Itx. Causes of death were declamping shock, cardiac tamponade with acute cellular rejection, dysmotility, and sepsis. Surgical complications consisted of 1 feeding jejunostomy displacement, and a minor leakage at a colo-colostomy site. One-year survival of the patient and graft was 73.33% (Kaplan-Meier survival curve). Although the total number of ITx is small, its social impact has been remarkable in changing the related laws and reimbursement policy in Korea.