Clinical Utility of Breast Ultrasound Images Synthesized by a Generative Adversarial Network

BACKGROUND AND OBJECTIVES

This study compares the clinical properties of original breast ultrasound images and those synthesized by a generative adversarial network (GAN) to assess the clinical usefulness of GAN-synthesized images.

MATERIALS AND METHODS

We retrospectively collected approximately 200 breast ultrasound images for each of five representative histological tissue types (cyst, fibroadenoma, scirrhous, solid, and tubule-forming invasive ductal carcinomas) as training images. A deep convolutional GAN (DCGAN) image-generation model synthesized images of the five histological types. Two diagnostic radiologists (reader 1 with 13 years of experience and reader 2 with 7 years of experience) were given a reading test consisting of 50 synthesized and 50 original images (≥1-month interval between sets) to assign the perceived histological tissue type. The percentages of correct diagnoses were calculated, and the reader agreement was assessed using the kappa coefficient.

RESULTS

The synthetic and original images were indistinguishable. The correct diagnostic rates from the synthetic images for readers 1 and 2 were 86.0% and 78.0% and from the original images were 88.0% and 78.0%, respectively. The kappa values were 0.625 and 0.650 for the synthetic and original images, respectively. The diagnoses made from the DCGAN synthetic images and original images were similar.

CONCLUSION

The DCGAN-synthesized images closely resemble the original ultrasound images in clinical characteristics, suggesting their potential utility in clinical education and training, particularly for enhancing diagnostic skills in breast ultrasound imaging.

Altered expression of hepatocyte growth factor in cardiac allografts of nonhuman primates

Hepatocyte growth factor (HGF) plays a critical role in transplant rejection. Herein we addressed whether HGF expression could be used for accurate and early diagnosis of acute and chronic rejection in cardiac transplantation. We used a heterotopic cardiac transplantation model using nonhuman primates (Macaca fuscata, n = 7). The grafts were harvested on days 1, 7, 22, 28, 40, 41, and 95 for histology and immunohistochemistry. Histopathologically, HGF was expressed in the spindle-shaped cells of the acutely rejecting myocardium. The expression of HGF was enhanced in both thickened intima and media of the coronary arteries. Altered HGF expression is a sensitive indicator for acute and chronic cardiac rejection.

X-ray diffractometer combining synchrotron radiation and pulsed magnetic fields up to 40 T

A synchrotron X-ray diffractometer incorporating a pulsed field magnet for high fields up to 40 T has been developed and a detailed description of this instrument is reported. The pulsed field magnet is composed of two coaxial coils with a gap of 3 mm at the mid-plane for passage of the X-rays. The pixel detector PILATUS 100K is used to store the diffracted X-rays. As a test of this instrument, X-ray diffraction by a powder sample of the antiferromagnet CoO is measured below the Néel temperature. A field-dependent lattice distortion of CoO due to magnetostriction is observed up to 38 T.

[Aortic valve replacement in a renal transplant recipient]

A 65-year-old male was admitted to our hospital for surgical treatment of congestive heart failure with aortic regurgitation. He had received renal transplantation 15 years before in the United States, and had been under immunosuppressive regimen with ciclosporin and mycophenolate mofetil. Although the renal allograft function had been gradually deteriorating, and preoperative serum creatinine level was 1.8 mg/dl, and it decreased to 1.5 mg/dl after aortic valve replacement. Cryopreserved aortic allograft was needed for the aortic valve replacement. The reasons are; the patient may need hemodialysis (HD) or retransplantation of the kidney in the future, and the immunosuppressive therapy for kidney will provide good immunologic environment for second allograft, i.e.--aortic valve. He tolerated the operation well and the immunosuppressive agents were continued in the perioperative period. He is now in New York Heart Association (NYHA) class I.

[Secondary left main trunk coronary artery shock syndrome]

A 71-year-old male patient was admitted to our hospital and diagnosed as inferior wall acute myocardial infarction (AMI). Coronary angiogram revealed 3 vessel disease and left main trunk coronary artery (LMT) lesion. Because right coronary artery (RCA) had been recanalised, he was scheduled to operation. On the 6th day after admission, another attack made him fell into secondary LMT shock syndrome and lung edema. Emergency operation was performed and he recovered from heart failure. Here we report the case and added some considerations.

'No-Touch' isolation procedure for ruptured mycotic abdominal aortic aneurysm

The present study reports a case of the successful surgical repair of a ruptured infra-renal mycotic abdominal aorta with Enterobactor cloacae in a 66-year-old man. During the operative procedure, an extra-anatomic bypass was installed before the laparotomy in order to avoid bacterial contamination. A complete resection of the infected aorta, tapering of the arterial stumps, wrapping of the omentum, and ligation of the aorta and arteries with Teflon tapes was carried out. The patient is alive and well 1 year postsurgery.

Early growth-response factor 1 and basic transcriptional element-binding protein 2 expression in cardiac allografts

Early growth-response factor 1 (Egr-1) and basic transcriptional element-binding protein 2 (BTEB2) are transcriptional factors that regulate multiple genes involved in phenotypic changes of smooth muscle cells (SMCs), one of the outstanding pathologic features of chronic cardiac allograft rejection. In this study, we used a heterotopic abdominal heart transplant model in monkeys to evaluate the roles of these molecules in graft coronary vasculopathy. We demonstrated that Egr-1 and BTEB2 are induced in vascular SMCs of rejected cardiac allografts well before morphologic changes, such as intimal thickening. These findings suggest that expression of Egr-1 and BTEB2 is one of the initial events in allograft angiopathy.

Characterization of inhibitory action of concanamycins against herpes simplex virus

Concanamycins A (Conmy A) and B (Conmy B), well-known inhibitors of the vacuolar proton-ATPase, were isolated from the culture broth of Streptomyces sp. strain FK51 as antiherpetic agents. These compounds showed potent inhibition of herpes simplex virus type 1 (HSV-1) replication in an in vitro assay system, having antiviral activities with 50% inhibitory concentrations of 0.072 and 0.51 ng/ml for Conmy A and Conmy B, respectively. While the attachment of HSV-1 to Vero cells was not inhibited, both of the compounds blocked the penetration of virus into host cells. When added to the late stages of virus replication, the concanamycins also exerted marked inhibitory effects on the production of viruses. Release of progeny viruses was found to be suppressed by the agents. SDS-PAGE analysis of isotope-labelled HSV-specific proteins revealed that the synthesis of beta proteins was moderately inhibited and some of the glycoproteins were synthesized with reduced molecular weights. Western blot analysis using antibodies against two HSV-specific glycoproteins (gC and gD) showed differences in their syntheses between untreated and Conmy A-treated cells. Syncytium formation by HSV-1 strain HF was inhibited, and small plaques with rounded cells were formed in Conmy A-treated cell cultures. When wild-type HSV-1 was serially propagated under the selective pressure of Conmy A, and the resulting progeny viruses were grown in drug-free medium, their plaque morphology of syncytium and sensitivity to Conmy A were the same as those of parent virus. From these findings, antiherpetic activities of Conmy A and B might be mainly dependent on their activities as vacuolar proton-ATPase inhibitors with intracellular translocation of glycoproteins and the inhibition of the maturation of virus glycoproteins.

Expression of membrane-type 1 matrix metalloproteinase in coronary vessels of allotransplanted primate hearts

BACKGROUND

The mechanisms of intimal thickening in cardiac allograft vasculopathy (CAV) remain controversial after heart transplantation. Matrix metalloproteinase-2 (MMP-2) plays a crucial role in degrading extracellular matrix (ECM) during neointimal formation. Recently, it has been revealed that MMP-2 is activated by membrane-type 1 matrix metalloproteinase (MT1-MMP). This process involves tissue inhibitor of MMP-2 (TIMP-2), forming an MT1-MMP/TIMP-2/pro-MMP-2 complex. In this study, we hypothesize that these components contribute to the pathogenesis of CAV.

METHODS

Heterotopic cardiac allografting was performed in randomly paired Japanese monkeys with an immunosuppressive regimen of intravenous administration of antihuman CD18 monoclonal antibody. The donor hearts were harvested at Days 22, 28, 40, 41, and 95 posttransplantation. We examined expression of MMP-2, MT1-MMP, and TIMP-2 of graft vessels using immunohistochemistry and protein level by western blot analysis.

RESULTS

Pathologically, various degrees of neointimal formation were observed. In the allografts harvested at Days 22, 28, 40, and 41, MT1-MMP was expressed in the endothelial cells and smooth muscle cells (SMCs) in media of some arteries without histological change, accompanied by expression of MMP-2 and TIMP-2. In the severely thickened neointima of the allograft harvested at Day 95, MMP-2 and faint MT1-MMP were expressed in SMCs of severely thickened neointima and media; TIMP-2 expression was seen only in noncollagenous tissue of severely thickened neointima. MMP-2 protein was more intensely expressed in the allograft harvested at Day 95 than in the allograft harvest at Day 41, while TIMP-2 protein level was almost same in the 2 samples.

CONCLUSION

We observed the simultaneous expression of MMP-2, MT1-MMP, and TIMP-2. Thus, ECM degradation triggered by MT1-MMP/TIMP-2/pro-MMP-2 complex could be a novel mechanism of CAV.

Gene therapy for attenuating cardiac allograft arteriopathy using ex vivo E2F decoy transfection by HVJ-AVE-liposome method in mice and nonhuman primates

Cardiac allograft arteriopathy, which limits the long-term survival of recipients, is characterized by diffuse intimal thickening composed of proliferative smooth muscle cells. The transcription factor E2F plays a pivotal role in the coordinated transcription of cell-cycle regulatory genes. To test the hypothesis that double-stranded DNA with specific affinity for E2F (E2F decoy) is effective in preventing intimal hyperplasia, we performed ex vivo single intraluminal delivery of E2F decoy into cardiac allografts of mice and Japanese monkeys using the hemagglutinating virus of Japan (HVJ) artificial viral envelope-liposome method. In murine models, antisense cyclin-dependent kinase 2 (cdk2) kinase oligodeoxynucleotide (ODN) and no transfers were performed to compare the effects. Severe intimal thickening was observed, and multiple cell-cycle regulatory genes were enhanced in untreated allografts. E2F decoy prevented neointimal formation and suppressed these genes for up to 8 weeks, whereas antisense cdk2 kinase ODN had limited effects. In primate models, E2F decoy dramatically prevented neointimal thickening and suppressed multiple cell-cycle regulatory genes, whereas intimal thickening developed in the nontransfected or mismatch decoy-transfected allografts. Gel mobility shift assay proved the specific effects of E2F decoy, and reverse transcriptase-polymerase chain reaction documented that neither complication nor dissemination of HVJ into other organs was observed. We demonstrate that ex vivo gene delivery to allografts is a potent strategy to modify allograft gene expression, resulting in prevention of graft arteriopathy without systemic adverse effects.

[A clinical study of posttraumatic hydrocephalus]

From 1989 to 1998, 721 patients with head injury were admitted to our department and 22 (3.1%) of them developed posttraumatic hydrocephalus. These patients included 16 males and 6 females, ranging in age from 17 to 86 years (mean age, 66 yrs) with peak incidence in the eighth decade. CT scan on admission immediately after head injury showed subarachnoid hemorrhage (SAH) in 18 cases. The other 4 cases without SAH had once suffered head injuries severe enough to give rise to consciousness disturbance. The typical clinical symptoms of hydrocephalus were observed in only 5 (23%) patients, and in the other 17 cases prolonged or deteriorated of consciousness disturbance were the main symptoms. Hydrocephalus was diagnosed between 1 and 3 months in 15 cases and in 7 cases after 4 months. Clinical improvement has been seen in 17 (77%) cases and marked recovery of consciousness was achieved in 12 cases after V-P shunt, but 5 cases with severe disturbance of consciousness revealed no improvement of clinical signs even after decrease of ventricular size. These results indicate that elderly patients with traumatic SAH should be followed up for at least 4 to 5 months, paying attention to development of hydrocephalus, and V-P shunt would be effective to improve consciousness disturbance in most of the cases.

Aortobronchial fistula late after transverse arch replacement

We report an unusual case of aortobronchial fistula late after transverse arch replacement caused by the remnant of a temporary bypass near the ascending aorta. In reconstructive surgery of the ascending aorta, antegrade perfusion is preferably performed through a side branch after completion of the distal anastomosis by some surgeons. This report suggests possible risk of a serious late complication unless the side branch is placed and tailored properly.

Altered expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in acutely rejected myocardium and coronary arteriosclerosis in cardiac allografts of nonhuman primates

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are important in any process of tissue remodeling. However, there is no report evaluating their expression in cardiac allografts in human or non-human primates. Heterotopic cardiac transplantation was performed on Japanese monkeys. Subjects were treated with chimeric anti-human lymphocyte function-associated antigen-1 monoclonal antibody for 2 weeks. Heart grafts were harvested at days 1-95 (n = 7). Native monkey hearts were used as controls (n = 2). We examined expression of MMP-2, MMP-9, TIMP-1, and TIMP-2 using immunohistochemistry and in situ reverse transcriptase polymerase chain reaction (RT-PCR). In the myocardium, the expression of MMP-2 was increased in the spindle-shaped cells of acutely rejected myocardial interstitium and prior to the presence of mononuclear cell infiltration at days 1-41. TIMP-1 and 2 expression was enhanced in association with the progression of fibrosis at days 40-95. In the coronary arteries of chronically rejected allografts, enhanced MMP and decreased TIMP expression was observed in both thickened intima and media at days 40-95. The medial MMP mRNA expression was observed before the development of intimal thickening occurred at days 7-28. MMPs are critical for the progression of acute and chronic rejection, and TIMP predominance plays important roles in fibrosis in association with acute rejection. Expression of MMPs and TIMPs is a sensitive indicator of acute and chronic cardiac rejection.

Ontogeny of antipig xenoantibody and hyperacute rejection

BACKGROUND

Neonatal primates have been reported to receive pig hearts without hyperacute rejection (HAR). We examined the ontogeny of the anti-pig xenoantibody (XenoAb) and HAR in the neonatal and infant monkeys.

METHODS

Twenty-six serum samples from 15 monkeys ages 14-192 days were subjected to hemagglutination titration against pig erythrocytes. Ten pig hearts were heterotopically transplanted into the monkeys.

RESULTS

Six monkeys, ages 52-114 days, received pig hearts without HAR, and those ages 129-191 days hyperacutely rejected them. XenoAb titers were increased according to the age (Spearman's rank correlation value=0.909 (P<0.01)). XenoAb titers in 16 monkeys <4 months were significantly (P<0.01) lower than those in 10 monkeys >4 months.

CONCLUSIONS

Anti-pig XenoAb titers increased with the age of the monkeys. XenoAb levels in monkeys >4 months are high enough to reject pig hearts hyperacutely.

Metastatic hepatocellular carcinoma obstructing the right ventricular outflow tract

A 49-year-old female with a past history of liver resection due to hepatocellular carcinoma was referred to our Department for treatment of a metastatic cardiac tumor obstructing the right ventricular outflow tract. She underwent operation twice with cardiopulmonary bypass, and symptoms were relieved. Metastasis from hepatocellular carcinoma to the heart is very rare, but should be taken into consideration during follow-up after treatment for a primary liver tumor.