Jingxuan Liu

Allorecognition by murine natural killer cells: lysis of T-lymphoblasts and rejection of bone-marrow grafts

Summary: Natural killer (NK) cells of inbred mice reject allogeneic bone‐marrow cells, and NK cells of F1 hybrid mice can reject parental bone‐marrow cells (hybrid resistance). In some cases these patterns of rejection can be mimicked in vitro by utilizing IL‐2 cultured NK effector cells and allogeneic or parental T‐lymphoblasts as target cells. Lysis of allogeneic parental targets in vitro can be explained on the basis of the missing self hypothesis. Subsets of NK cells that bear non‐overlapping MHC class I inhibitory receptors belonging to the Ly49 family lyse allogeneic targets because they do not express self class I molectiles of the NK cell donor. Parental strain targets are lysed because they do not express all of the self class I antigens of the Fl hybrid, and hence fail to deliver inhibitory signals to all subsets of Fl NK cells. The expression of Ly49 receptors on NK cells is regulated by liost MHC to ensure maximal sensitivity to alterations in self class I molecules and to prevent autoreactivity. In many instances, however, the rejection of allogeneic bone marrow cells in vivo cannot be readily explained by the missing self hypothesis. In these instances, it appears that rejection is initiated by class 1 MHC receptors on NK ceils Out recognize allogeneic class I molecules as non‐self, and activate rather than inhibit NK cell function.

Role of murine NK cells and their receptors in hybrid resistance

Hybrid resistance refers to the rejection of parental strain bone marrow cells by natural killer cells of mice that are F1 hybrids derived from two inbred parental strains. This pattern of rejection is not seen in solid organ transplants. Progress in understanding this exception to the laws of transplantation genetics has occurred with the recent discovery of negative signaling receptors for MHC class I molecules. In the last year the discovery of natural killer cell subsets with non-overlapping inhibitory receptors for parental class I molecules has provided an explanation for hybrid resistance. In some instances, however, positive rather than negative signaling seems to be the basis for rejection of allogeneic as well as parental marrow cell grafts.

In vivo bladder imaging with microelectromechanical-systems-based endoscopic spectral domain optical coherence tomography.

We report the recent technical improvements in our microelectromechanical systems (MEMS)-based spectral-domain endoscopic OCT (SDEOCT) and applications for in vivo bladder imaging diagnosis. With the technical advances in MEMS mirror fabrication and endoscopic light coupling methods, the new SDEOCT system is able to visualize morphological details of the urinary bladder with high image fidelity close to bench-top OCT (e.g., 10 mum12 mum axial/lateral resolutions, >108 dB dynamic range) at a fourfold to eightfold improved frame rate. An in vivo animal study based on a porcine acute inflammation model following protamine sulfate instillation is performed to further evaluate the utility of SDEOCT system to delineate bladder morphology and inflammatory lesions as well as to detect subsurface blood flow. In addition, a preliminary clinical study is performed to identify the morphological features pertinent to bladder cancer diagnosis, including loss of boundary or image contrast between urothelium and the underlying layers, heterogeneous patterns in the cancerous urothelium, and margin between normal and bladder cancers. The results of a human study (91% sensitivity, 80% specificity) suggest that SDEOCT enables a high-resolution cross-sectional image of human bladder structures to detect transitional cell carcinomas (TCC); however, due to reduced imaging depth of SDEOCT in cancerous lesions, staging of bladder cancers may be limited to T1 to T2a (prior to muscle invasion).

Ly49I NK Cell Receptor Transgene Inhibition of Rejection of H2b Mouse Bone Marrow Transplants

The Ly49 family of genes encode NK cell receptors that bind class I MHC Ags and transmit negative signals if the cytoplasmic domains have immunoregulatory tyrosine-based inhibitory motifs (ITIMs). 5E6 mAbs recognize Ly49C and Ly49I receptors and depletion of 5E6+ NK cells prevents rejection of allogeneic or parental-strain H2d bone marrow cell (BMC) grafts. To determine the function of the Ly49I gene in the rejection of BMC grafts, we transfected fertilized eggs of FVB mice with a vector containing DNA for B6 strain Ly49I (Ly49IB6). Ly49IB6 is ITIM+ and is recognized by 5E6 as well as Ly49I-specific 8H7 mAbs. Normal FVB H2q mice reject H2b but not H2d BMC allografts, and the rejection of H2b BMC was inhibited partially by anti-NK1.1 and completely by anti-asialo GM1, but not by anti-CD8, Abs. In FVB mice, NK1.1 is expressed on only 60% NK cells. FVB.Ly49IB6 hosts failed to reject H2d or H2b BMC, but did reject class I-deficient TAP-1−/− BMC, indicating that NK cells were functional. Nondepleting doses of anti-Ly49I Abs reversed the acceptance of H2b BMC by FVB.Ly49IB6 mice. FVB.Ly49IB6+/− mice were crossed and back-crossed with 129 mice—H2b, 5E6−, poor responders to H2d BMC grafts. While transgene-negative H2b/q F1 or first-generation back-crossed mice rejected H2b marrow grafts (hybrid resistance), transgene-positive mice did not. Thus B6 strain Ly49I receptors transmit inhibitory signals from H2b MHC class I molecules. Moreover, Ly49IB6 has no positive influence on the rejection of H2d allografts.

Assessment of Dermal Wound Repair after Collagen Implantation with Optical Coherence Tomography

We present an animal study to examine the utility and potential limitations of optical coherence tomography (OCT) for noninvasive evaluation of biomaterial scaffold-assisted wound healing. The transverse and axial resolutions of the OCT system at the wavelength of 1.3 microm were 12 and 10 microm, respectively. A murine full-thickness transcutaneous wound model was employed, in which a phi 10 mm full-thickness wound was created on the back of each male Balb/cJ mouse and a porous collagen scaffold was implanted in the wound bed followed by coverage with a Tegaderm film. Sequential cross-sectional OCT scans were performed at different time points postsurgical intervention to track morphological changes during wound recovery, and the captured OCT images were validated by their corresponding histological specimens. The results indicated that with removal of the high-scattering skin, OCT was capable of imaging to a depth of over 1.5 mm into the wound bed and differentiating various features evolved during wound healing at a high resolution approaching histopathology. OCT was able to not only delineate the epidermis and dermis of normal mouse skin, but also differentiate collagen implant from the underlying subcutaneous tissue; besides, it could track the wound size changes in both lateral and vertical directions. More importantly, OCT was able to detect inflammation, early re-epithelialization, and resorption of the collagen scaffold. These findings suggested the potential of OCT for noninvasive and high-resolution monitoring of assisted wound healing in vivo, longitudinally, and instantaneously.

Elevated Expression of Squamous Cell Carcinoma Antigen (SCCA) Is Associated with Human Breast Carcinoma

Squamous cell carcinoma antigen (SCCA) belongs to the serine protease inhibitor (Serpin) family of proteins. Elevated expression of SCCA has been used as a biomarker for aggressive squamous cell carcinoma (SCC) in cancers of the cervix, lung, head and neck, and liver. However, SCCA expression in breast cancer has not been investigated. Immunohistochemical analysis of SCCA expression was performed on tissue microarrays containing breast tumor tissues (n = 1,360) and normal breast epithelium (n = 124). SCCA expression was scored on a tiered scale (0-3) independently by two evaluators blind to the patients clinical status. SCCA expression was observed in Grade I (0.3%), Grade II (2.5%), and Grade III (9.4%) breast cancers (p<0.0001). Comparing tissues categorized into the three non-metastatic TNM stages, I-III, SCCA positivity was seen in 2.4% of Stage I cancers, 3.1% of Stage II cancers, and 8.6% of Stage III breast cancers (p = 0.0005). No positive staining was observed in normal/non-neoplastic breast tissue (0 out of 124). SCCA expression also correlated to estrogen receptor/progesterone receptor (ER/PR) double-negative tumors (p = 0.0009). Compared to SCCA-negative patients, SCCA-positive patients had both a worse overall survival and recurrence-free survival (p<0.0001 and p<0.0001, respectively). This study shows that SCCA is associated with both advanced stage and high grade human breast carcinoma, and suggests the necessity to further explore the role of SCCA in breast cancer development and treatment.

High-resolution imaging diagnosis and staging of bladder cancer: comparison between optical coherence tomography and high-frequency ultrasound

A comparative study between 1.3-microm optical coherence tomography (OCT) and 40-MHz high-frequency ultrasound (HFUS) is presented to enhance imaging of bladder cancers ex vivo. A standard rat bladder cancer model in which transitional cell carcinoma (TCC) was induced by intravesical instillation of AY-27 cells was followed independently with both OCT and HFUS, and the image identifications were compared to histological confirmations. Results indicate that both OCT and HFUS were able to delineate the morphology of rat bladder [e.g., the urothelium (low backscattering/echo) and the underlying lamina propria and muscularis (high backscattering/echo]. OCT differentiated inflammatory lesions (e.g., edema, infiltrates and vasodilatation in lamina propria, hyperplasia) and TCC based on characterization of urothelial thickening and enhanced backscattering or heterogeneity (e.g., papillary features), which HFUS failed due to insufficient image resolution and contrast. On the other hand, HFUS was able to stage large T2 tumors that OCT failed due to limited imaging depth. The results suggest that multimodality cystoscopy combining OCT and HFUS may have the potential to enhance the diagnosis and staging of bladder cancers and to guide tumor resection, in which both high resolution (approximately 10 microm) and enhanced penetration (> 3mm) are desirable.

Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) : The new thinking

TTP and HUS are two disorders with many similarities. Though their first descriptions appeared at different time in history, there has been a trend among physicians to consider them as the same clinical entity. However, in recent years new research findings on the pathophysiology of TTP and HUS have revealed some differences between the two disorders. In this paper, we will review the current approaches to the clinical and laboratory diagnosis of TTP and HUS, as well as therapeutic strategies. We will also summarize the recent advances in three areas in the study of the pathophysiology of TTP and HUS, namely the newly discovered von Willebrand factor multimer-cleaving protease, endothelial cell apoptosis induced by serum from patients with TTP and atypical HUS and the activation of complement system. Since distinguishing and differentiating between TTP and HUS may help to develop more effective therapies targeted at key steps␣of the disease development, we will discuss possible ways of reclassifying the TTP-HUS disorders. In the end, we also present our views on possible future development.

Angiolymphoid hyperplasia involving large arteries

Angiolymphoid hyperplasia with eosinophilia (ALHE) is a rare vascular proliferative disorder, which most commonly involves the skin of the head and neck regions. Noncutaneous localization of this pathology is unusual, and its primary localization in large arteries presenting as a pulsatile mass is extremely rare. We report here two cases of ALHE manifested as masses of the occipital and brachial artery. ALHE should be considered in the differential diagnosis of localized peripheral arterial masses in young patients.

Sertoliform endometrioid carcinoma of the endometrium with dual immunophenotypes for epithelial membrane antigen and inhibin α: Case report and literature review

Summary We report a rare case of sertoliform endometrioid carcinoma of the endometrium in a 71-year-old African American woman who presented with postmenopausal bleeding. Her medical condition was remarkable for hypertension, diabetes, and obesity. She underwent total hysterectomy, right salpingo-oophorectomy and lymph node sampling. The endometrium was occupied by a 4.5-cm solid polypoid tumor, which grossly invaded into the myometrium. Microscopically, the tumor consisted of small hollow tubules, anastomosing cords and trabeculae, and tightly packed nests. Microglandular areas mimicking adult granulosa cell tumors were also present. But true Call-Exner bodies were absent. Component of typical endometrioid carcinoma was noted only focally. The uninvolved endometrium demonstrated atypical complex hyperplasia. The tumor cells were diffusely immunoreactive for epithelial membrane antigen, estrogen receptor, and progesterone receptor (PR), and focally for vimentin. The tumor cells were also diffusely positive for inhibin &agr; and CD99. Immunostains for other sex cord markers (calretinin, WT-1, and Melan-A) were also positive in approximately 30% to 40% of the tumor cells. Immunostains for CD10, smooth muscle actin, desmin, or HHF35 were negative. Two ovarian sertoliform endometrioid carcinomas from our archived tissue were, however, immunoreactive for epithelial membrane antigen but negative for inhibin &agr;. Despite the prominent sertoliform features, both histologically and immunohistochemically, the tumor was of a high-grade endometrial carcinoma and will likely behave as such. As of today, dual differentiation of epithelium and sex cord by immunohistochemical staining has not been demonstrated in sertoliform endometrioid carcinomas of either endometrial or ovarian origin. Our case is the first documentation of such example and suggests that endometrial carcinoma can undergo true sex cord differentiation.