Prominent Lesions Research Articles

Abstract 3440: CRM1-Selective Inhibitors of Nuclear Export (SINE) reduce the incidence of tumor spreading and improve overall survival in preclinical models of prostate cancer.

Abstract Background: CRM1 (XPO1) is the exclusive exportin mediating transport of most tumor suppressor proteins (TSPs) including p53, pRb, FOXO, APC and p21 out of the nucleus, abrogating their function. Methods: We tested the effects of the potent, selective, clinical stage oral SINE compound KPT-330 in prostate cancer (PrCa) models. Male SCID mice orthotopically (intraprostatic) inoculated with the DU145 PrCa, known to produce highly metastatic tumors with visceral metastases. In parallel, male CD1-nu/nu mice were inoculated with intracardiac and intratibial injections of the aggressive/bone-derived PrCa PC3, known to produce prominent osteolytic bone lesions. The effects of SINEs KPT-330 and KPT-251 on metastatic spreading were determined. Results: We previously demonstrated that SINE CRM1 antagonists KPT330 and KPT251 have potent antitumor effects on PrCa both in vitro and in vivo. Here, we demonstrate that KPT-330 reduces intraprostatic DU145 tumor burden as well as the incidence of macroscopic metastases to lymph nodes, liver and lung, in a dose-dependent manner. The DU145 tumor burden was reduced by 41% with KPT-330 (4 mg/kg qd/5 days) and 61% (10 mg/kg q 3-4 d x 7) when compared to controls. The incidence of PC3-derived bone metastases were significantly reduced with KPT-330 at 10 mg/kg (q 2d x 3 weeks). At 50 days after cell injection, 80% (8/10) of controls and 0% (0/10) of the KPT-330-treated animals developed X-Ray evidence of bone lesions (p<0.05). The burden of bone metastases, measured by lytic bone area, was significantly higher in controls than in KPT-330-treated animals. Similarly, after intra-tibial injection, the lytic areas were higher in controls than in the KPT-330 group (p<0.05). The level of serum markers of osteoclast activity (TRAP and type I collagen fragment, CTX), was significantly higher in controls than in KPT-330-treated animals. The related SINE KPT-251 (100 mg/Kg q 2d x 3 weeks) confirmed the reduction of bone metastasis following CRM1 inhibition. The overall and disease free survival, evaluated at 170 days after tumor injection, were significantly higher in KPT-330- and KPT-251-treated animals versus controls (P< 0.0001). Treatment of PC3 and DU145 cells with KPT-330 lead to significant reductions in the secretion of proteolytic enzymes (MMP-9, MMP-2, uPA) as well as reduced ability of tumor cells to migrate and invade Matrigel. Impaired secretion of pro-angiogenic (VEGF, IL6, IL8) and pro-osteolytic (RANKL, IL6) cytokines was also observed. Conclusions: These data show that selective blockade of CRM1-dependent nuclear export has direct antitumor, anti-metastatic and anti-osteolytic activities in PrCa and thus represents a novel approach for the treatment of advanced/ metastatic PrCa. KPT-330 is now in Phase 1 clinical trials in patients with advanced solid tumors (clinicaltrailas.gov: NCT01607905). Citation Format: Giovanni Luca Gravina, Monica Tortoreto, Andrea Mancini, Paola Muzi, Luca Ventura, Sandra D'ascenzo, Alessandro Addis, Yosef Landesman, Dilara McCauley, Vincenza Dolo, Michael Kauffman, Sharon Shacham, Nadia Zaffaroni, Claudio Festuccia. CRM1-Selective Inhibitors of Nuclear Export (SINE) reduce the incidence of tumor spreading and improve overall survival in preclinical models of prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3440. doi:10.1158/1538-7445.AM2013-3440

Abstract 2300: Novel conditional knockout of VHL in the kidney leads to precancerous lesions that exhibit an inflammatory response.

Abstract Mutations of the tumor suppressor gene von Hippel-Lindau (VHL) can lead to benign and malignant tumors, including the devastating cancer clear-cell renal cell carcinoma (ccRCC). Using a Cre mouse strain that is driven by the Hoxb7 gene promoter, we have generated a novel Vhl conditional knockout strain that exhibits prominent precancerous lesions in the mutant mouse kidneys. Hoxb7-Cre is expressed in collecting ducts in embryonic and adult kidneys, as well as in the convoluted distal tubules in adult kidneys. Pre-cancerous kidney lesions are observed in as early as 2 month old homozygous viable mice, which are not seen in wild-type littermates. Investigation of H&E sections showed that lesions contained dilated kidney tubules (mini-cysts), cell piling-up, clear cells, and infiltrating immune cells. Collagen accumulation was observed in these lesions indicating fibrosis. Lesions are also dysplastic distinguished by breakdown of the basement membrane and expression of mesenchymal markers. Consistent with the known ccRCC phenotype, increased blood vessel accumulation in Vhl knockouts was also observed when compared to wild-type littermates. Importantly, hyperplasia (presence of Ki67-positive cells) is also prominent. An abundance of macrophages are detected in lesions starting at 2 months and in older mice the immune cell population in lesions expanded to B-cells and T-cells. The pre-cancerous lesion state in our mutants also provides us an opportunity to analyze the potential role of inflammation in ccRCC progression. These lesions co-express well known pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-6 in tubules surrounding precancerous lesions. One of the major functions of VHL is to act as an E3 ubiquitin ligase, in which its major target for proteasomal degradation is hypoxia-inducible factor α (HIFα). HIFα target genes glucose transporter (Glut1) and carbonic anhydrase IX (CAIX), were expressed in lesion tubules, thus suggesting HIFα contribution to the fibrotic defects we have seen. Mechanistically it can be suggested that dual knockdown of HIF-1α or -2α and VHL would restore kidneys to be similar to wild-type littermates. Indeed the frequency of lesions was greatly reduced in double knockouts of VHL HIF1-α and VHL Hif-2α. IL-1β and IL-6 cytokine activity is known to simulate Janus kinase (JAK)-signaling, which has recently emerged as an important promoter of tumor growth. Specifically JAK2 expression is increased in VHL mutant renal cell carcinoma cell lines and has been shown to promote cell invasion. VHL conditional knockouts treated with a JAK2 inhibitor revealed a decrease in the frequency of lesions, suggesting this mechanism is involved in lesion development. Taken together these results suggest a prominent role of the inflammatory response in the early onset of ccRCC. Citation Format: Tracy L. Pritchett, Hannah Bader, Tien Hsu. Novel conditional knockout of VHL in the kidney leads to precancerous lesions that exhibit an inflammatory response. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2300. doi:10.1158/1538-7445.AM2013-2300

Laser therapy treatment of phacomatosis pigmentovascularis type II: two case reports

IntroductionPhacomatosis pigmentovascularis is a rare congenital condition characterized by vascular malformation associated with extensive pigmented nevi. Even though it forms a large, prominent skin lesion, therapy for phacomatosis pigmentovascularis is rarely discussed. To the best of our knowledge, this is the first report of phacomatosis pigmentovascularis type II treated with combined laser therapy using Q-switched alexandrite and long-pulsed dye lasers.Case presentationsIn the first of two cases reported here, a 2-week-old Japanese baby girl was given a diagnosis of phacomatosis pigmentovascularis type II and Klippel–Trénaunay syndrome because of port-wine stains, cutis marmorata telangiectatica congenita, and aberrant Mongolian spots over her trunk and limbs. After five laser therapy sessions under general anesthesia, her aberrant Mongolian spots and port-wine stains have improved. But interestingly, the cutis marmorata telangiectatica congenita on the patient's back has improved without laser therapy.In the second case, a 4-month-old Japanese baby boy was referred to us because of port-wine stains, cutis marmorata telangiectatica congenita, and aberrant Mongolian spots over his face, trunk and limbs. Phacomatosis pigmentovascularis type II was diagnosed and laser therapy was started. After three laser therapy sessions under general anesthesia, the aberrant Mongolian spots and port-wine stains have improved. The cutis marmorata telangiectatica congenita on the baby's back, buttocks, and arms has faded somewhat without laser therapy.ConclusionsCombined laser therapy improved the phacomatosis pigmentovascularis skin lesions, but was not effective for the cutis marmorata telangiectatica congenita with hemiatrophy. Cutis marmorata telangiectatica congenita without atrophy can be expected to improve on its own. Our results will assist physicians considering how best to treat patients with phacomatosis pigmentovascularis.

Unusual Spinal Dysraphic Lesions

Human tail and multiple spinal dysraphism are unusual congenital malformations. Human tail appeared as a prominent lesion from the lumbosacrococcygeal region, generally without connection between the tail and the neurospinal axis. Spinal dysraphisms are usually isolated, reaching 0.038% of incidence of multiple spinal dysraphisms in the same child. There were three cases described of unusual spinal dysraphic lesions: two cases of human tail and a case of a multiple thoracic myelomeningocele. The literature about diagnosis and treatment was reviewed. Microsurgical technique was performed to provide better exploration of the lesions, and resection could be done in those congenital malformations, without morbidity.

Cholangiocarcinoma Masquerading as an Ovarian Tumour

Department of Medicine (Division of Gastroenterology), St Boniface General Hospital, University of Manitoba, Winnipeg, Manitoba Correspondence: Dr Mayur Brahmania, Department of Medicine (Division of Gastroenterology), St Boniface General Hospital, 804F-175 McDermot Avenue, Winnipeg, Manitoba R3E 3P4. Telephone 204-789-3369, fax 204-789-3972, e-mail mbrahmania@gmail.com Received for publiction September 24, 2012. Accepted October 1, 2012 Case Presentation A 76-year-old woman presented to the emergency department complaining of nausea, vomiting, diarrhea, right-sided abdominal pain and early satiety. Her physical examination was within normal limits, with the exception of nodularity in the cul-de-sac and right parametrium on pelvirectal examination. Liver enzyme levels were elevated: aspartate aminotransferase 150 U/L; alanine amonotransferase 369 U/L; gammaglutamyl transferase 953 U/L; alkaline phosphatase 370 U/L; and a direct bilirubin level of 12 umol/L. A computed tomography scan of the abdomen and pelvis showed minimal dilation of the biliary system, with no obvious mass lesions or obstruction (Figure 1). However, multiple soft tissue nodules within the omentum and a prominent cystic lesion within the right adnexa were apparent. Pelvic ultrasound revealed a multiseptated right adnexal mass 6.2 cm in size, which raised concern for an ovarian cystic neoplasm. A subsequent carbohydrate antigen (CA) 125 level of 129 U/mL was measured. The patient underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy with pelvic lymph node dissection, omentectomy, appendectomy, and resection of the retroperitoneal mass in the posterior cul-de-sac and left uterosacral ligament. A frozen section of the right adnexal mass intraoperatively showed a mucinous cystadenoma with no evidence of malignancy (Figure 2). However, final pathology results yielded a well-differentiated mucinous adenocarcinoma consistent with metastasis from a primary cholangiocarcinoma. Metastatic cholangiocarcinoma was also identified in the cervix, uterine serosa, left fallopian tube, retroperitoneal posterior cul-de-sac lesion, left uterosacral lesion and the omentum. Both the ovarian neoplasm and omental deposits stained negative for CA 125. A serum CA 19.9 level of 30,000 U/mL was measured, necessitating an endoscopic retrograde cholangiopancreatography (ERCP) for further evaluation. ERCP demonstrated a complete obstruction/stricture 3 cm in size in the proximal common hepatic duct up to the hilum. A biliary stent was successfully placed above the stricture with adequate drainage of bile. DisCussion Cholangiocarcinoma (CC) is a rare malignancy of the biliary epithelium within the intrahepatic or extrahepatic bile ducts. It carries a poor prognosis and surgical management is the only curative treatment currently available. However, surgery is often extensive and is associated with significant morbidity and mortality (1). CC with metastasis to the ovary can present a diagnostic challenge because it has the propensity to mimic primary mucinous neoplasms (2,3). Intraoperative frozen sectioning provides a limited sample and can cause significant error, as in the present case. Therefore, multiple sampling, histological staining, clinical findings and gross features are extremely important in the diagnosis of metastatic CC in which an ovarian mass is the initial discovery. The literature regarding ovarian metastasis from the biliary system is limited. An autopsy study from Japan (3) suggested that CC is likely under-reported. However, due to differing incidences of primary tumours around the world, it is difficult to infer whether this is also the case in North America (3). To the best of our knowledge, the present case is the first to be reported in Canada. images of the month

Optical Coherence Tomography for Multifocal Vitelliform Macular Dystrophy

To describe the optical coherence tomography (OCT) features of multifocal vitelliform macular dystrophy (VMD). Five patients (10 eyes) with multifocal VMD were examined by slit lamp biomicroscopy, fundus photography, and OCT. Serous retinal detachment was present in the macular area in all eyes. A hyperreflective inner/outer segment interface was observed in the macula in nine of them. High reflectivity was homogeneous in six eyes of three patients with no prominent macular lesion. Retinoschisis-like changes could be clearly seen in four eyes evaluated by high-resolution OCT. A hyporeflectivity corresponded to the inner nuclear layer in two eyes. In four eyes with prominent macular lesions, a hyperreflective area between the hyporeflective outer nuclear layer and the hyperreflective retinal pigment epithelium layer was detectable. Although the fundus appearance of multifocal VMD is quite variable, OCT features of the disease are relatively uniform. Optical coherence tomography could help the pathological interpretation and facilitate the diagnosis of VMD.

Toxicity of melamine, an adulterant in fish feeds: experimental assessment of its effects on tilapia

Unscrupulous inclusion of melamine in fish feeds can be harmful to fish and may be hazardous to human health. An eight-week feeding trial examined the effects of melamine (inclusion levels; 5-30 g kg⁻¹ feed) on the growth performance, feed efficiency, histopathological changes and melamine residues in sex-reversed red tilapia, Oreochromis niloticus (L.) × O.mossambicus (Peters). Fish which received melamine-containing feeds grew less, utilized feeds less efficiently and performed poorly, besides exhibiting defects such as fin erosion, anorexia, sluggish swimming behaviour, paling/darkening of skin and low survival. Melamine concentration in the fish reflected its inclusion level in the feeds, and the content was higher in the viscera than in the fish fillet or whole fish. Histopathological alterations were evident in the kidney, liver and gills of fish subjected to melamine treatment - the severity of lesions corresponded to its dosage. Enlargement of renal tubules was observed in the kidney of fish fed with ≥10 g melamine kg⁻¹ feed, although, crystals were not deposited. Fish subjected to melamine insult had more prominent lesions in liver than in kidney. Toxic effects on the gills manifested as epithelial hyperplasia of the primary and secondary lamellae. The anomalies were severe at higher intake levels of melamine.

Electrocorticographic evidence of perituberal cortex epileptogenicity in tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is a multisystem autosomal dominant disorder resulting in hamartomas of several organs. Cortical tubers are the most prominent brain lesions in TSC. Treatment-resistant epilepsy often develops early in life in patients with TSC and is associated with severe intellectual and behavioral impairments. Seizures may remit following epilepsy surgery in selected cases, yet it remains unclear whether the tuber or the perituberal cortex is the source of seizure onset. In this study, the authors reviewed the onset of seizures in patients in whom depth electrodes had been placed within or adjacent to cortical tubers. After obtaining institutional review board approval, the authors retrospectively reviewed data from 12 pediatric patients with multifocal TSC and treatment-resistant epilepsy who had undergone invasive intracranial electroencephalographic monitoring. Tubers were identified on postimplantation MRI, and all depth electrodes were located. Depth electrode contacts were classified visually as either tuber/perituberal cortex or nontuber/nonperituberal cortex. Board-certified clinical neurophysiologists reviewed the seizures to identify all electrodes involved in the ictal onset. Among 309 recorded seizures, 104 unique ictal onset patterns were identified. Of the 11 patients with electrodes recording in a tuber, 9 had seizure onsets involving the tuber. Similarly, of the 9 patients with perituberal recording electrodes, 7 had perituberal ictal onsets. Overall, there was no difference in the percentage of contacts involved in seizure onset between the tuber and perituberal cortex. In a subset of 7 patients in whom at least 1 depth electrode contact was within the tuber and 1 was in the perituberal cortex, there was no difference between the percentage of tuber and perituberal onsets. Findings demonstrated heterogeneity in the ictal onset patterns as well as involvement of the tuber and perituberal cortex within and between patients. Although the data are limited by the restricted region(s) sampled with intracranial electrodes, they do suggest that cortical hyperexcitability in TSC may derive from the tuber or surrounding cortex.

Role of Microglia in Oxidative Toxicity Associated with Encephalomycarditis Virus Infection in the Central Nervous System

The single-stranded RNA encephalomyocarditis virus (EMCV) can replicate in the central nervous system (CNS) and lead to prominent brain lesions in the stratum pyramidale hippocampus and the stratum granulosum cerebelli. Activated microglia cells infected by EMCV produce a massive burst of reactive oxygen species (ROS) via NADPH oxidase 2 (NOX2) activation, leading to neuronal death. Balancing this effect is mechanisms by which ROS are eliminated from the CNS. Cellular prion protein (PrPC) plays an important antioxidant role and contributes to cellular defense against EMCV infection. This review introduces recent knowledge on brain injury induced by EMCV infection via ROS generation as well as the involvement of various mediators and regulators in the pathogenesis.

Hereditary myopathy with early respiratory failure associated with a mutation in A-band titin

Hereditary myopathy with early respiratory failure and extensive myofibrillar lesions has been described in sporadic and familial cases and linked to various chromosomal regions. The mutated gene is unknown in most cases. We studied eight individuals, from three apparently unrelated families, with clinical and pathological features of hereditary myopathy with early respiratory failure. The investigations included clinical examination, muscle histopathology and genetic analysis by whole exome sequencing and single nucleotide polymorphism arrays. All patients had adult onset muscle weakness in the pelvic girdle, neck flexors, respiratory and trunk muscles, and the majority had prominent calf hypertrophy. Examination of pulmonary function showed decreased vital capacity. No signs of cardiac muscle involvement were found. Muscle histopathological features included marked muscle fibre size variation, fibre splitting, numerous internal nuclei and fatty infiltration. Frequent groups of fibres showed eosinophilic inclusions and deposits. At the ultrastructural level, there were extensive myofibrillar lesions with marked Z-disc alterations. Whole exome sequencing in four individuals from one family revealed a missense mutation, g.274375T>C; p.Cys30071Arg, in the titin gene (TTN). The mutation, which changes a highly conserved residue in the myosin binding A-band titin, was demonstrated to segregate with the disease in all three families. High density single nucleotide polymorphism arrays covering the entire genome demonstrated sharing of a 6.99 Mb haplotype, located in chromosome region 2q31 including TTN, indicating common ancestry. Our results demonstrate a novel and the first disease-causing mutation in A-band titin associated with hereditary myopathy with early respiratory failure. The typical histopathological features with prominent myofibrillar lesions and inclusions in muscle and respiratory failure early in the clinical course should be incentives for analysis of TTN mutations.

Abstract 5626: FKBP51 is a crucial modulator of melanoma plasticity and promising molecular target for preventing melanoma metastasis

Abstract FKBP51, a protein with a relevant role in developmental stages in mammals and other organisms, is highly expressed in melanoma and correlates with tumor aggressiveness and resistance to therapy. We found that FKBP51 positively regulates melanoma cancer stem cell (CSC) phenotype at the transcriptional level. We also found that melanoma CSCs are endowed with epithelial to mesenchimal transition (EMT) traits. The immunochemistry study of 10 primitive cutaneous and 20 brain melanoma metastases showed that melanocytic cells capable of extravasation and subverting the architecture of metastatic tissue display intense FKBP51 nuclear signal and cytoplasmic positivity for the CSC marker nestin. These findings support the conclusion that the genetic programs of cancer stemness and invasiveness overlap in melanoma, and that FKBP51 plays a pivotal role in sustaining such a program. To confirm the role of FKBP51 in melanoma invasion, we utilized an experimental metastasis model. Animal studies were performed in accordance with NIH recommendations and the approval of the local institutional animal research committee. Injecting SAN melanoma cells into the tail vein of IL2γ-NOD-SCID mice produced prominent multifocal lesions in lungs and liver. We systemically administered two separate doses of FKBP51 siRNA to mice after the injection of melanoma cells. Organ colonization was evaluated both in live animals and post mortem. Qualitative PET/CT image analysis demonstrated low FDG uptake limited to small areas in lungs and liver. By contrast, untreated mice had diffuse metastatic liver and lung lesions and high FDG uptake in the same organs. Quantitative analysis performed on PET/CT images revealed that mean standardized uptake values (SUV) in treated mice were significantly lower than in untreated mice, both for lungs and liver. High Frequency Ultrasound examination revealed few or no liver metastases in treated mice versus untreated mice. Post-mortem organ examination showed a dramatic difference between the morphologically preserved organs dissected from treated mice, and severely compromised organs from untreated mice. The histological examination confirmed these findings. Most interestingly, invading cells co-expressed FKBP51 and nestin. Our study suggests a prominent role for FKBP51 in the pathogenesis of metastatic melanoma; we envision that targeting this protein for melanoma metastasis prevention may produce a successful outcome. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5626. doi:1538-7445.AM2012-5626

Overexpression of AtOGG1, a DNA glycosylase/AP lyase, enhances seed longevity and abiotic stress tolerance in Arabidopsis

Reactive oxygen species (ROS) are toxic by-products generated continuously during seed desiccation, storage, and germination, resulting in seed deterioration and therefore decreased seed longevity. The toxicity of ROS is due to their indiscriminate reactivity with almost any constituent of the cell, such as lipids, proteins, and DNA. The damage to the genome induced by ROS has been recognized as an important cause of seed deterioration. A prominent DNA lesion induced by ROS is 7,8-dihydro-8-oxoguanine (8-oxo-G), which can form base pairs with adenine instead of cytosine during DNA replication and leads to GC→TA transversions. In Arabidopsis, AtOGG1 is a DNA glycosylase/apurinic/apyrimidinic (AP) lyase that is involved in base excision repair for eliminating 8-oxo-G from DNA. In this study, the functions of AtOGG1 were elaborated. The transcript of AtOGG1 was detected in seeds, and it was strongly up-regulated during seed desiccation and imbibition. Analysis of transformed Arabidopsis protoplasts demonstrated that AtOGG1-yellow fluorescent protein fusion protein localized to the nucleus. Overexpression of AtOGG1 in Arabidopsis enhanced seed resistance to controlled deterioration treatment. In addition, the content of 8-hydroxy-2'-deoxyguanosine (8-oxo-dG) in transgenic seeds was reduced compared to wild-type seeds, indicating a DNA damage-repair function of AtOGG1 in vivo. Furthermore, transgenic seeds exhibited increased germination ability under abiotic stresses such as methyl viologen, NaCl, mannitol, and high temperatures. Taken together, our results demonstrated that overexpression of AtOGG1 in Arabidopsis enhances seed longevity and abiotic stress tolerance.

Clinicopathologic features of primary thymic extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue type

To study the clinicopathologic features of primary thymic extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT). The clinical and pathologic findings were evaluated in 3 cases of biopsy confirmed thymic MALT lymphoma. The clincopathologic features, treatment and prognosis were discussed and literatures reviewed. One male and two female patients presented with asymptomatic mediastinal masses with a history of Sjögren syndrome. They were aged 36, 35 and 41 years respectively, and only one patient had B symptoms. Grossly, all three tumors were encapsulated and had multiple variable-sized cysts on cut-surface. Histopathologically, the normal thymic lobular architecture was effaced by abnormal dense lymphoid infiltration. Prominent lymphoepithelial lesions were formed by centrocyte-like cells infiltrating and expanding Hassall's corpuscles and epithelial cyst lining. All cases showed apparent plasmacytic differentiation. Immunohistochemically, the tumor cells were positive for CD20, CD79a, bcl-2 and negative for CD3, CD5, cyclin D1, CD43, CD10, bcl-6, and CD23. The plasma cells showed kappa light chain restriction. Immunoglobulin heavy chain rearrangement in three cases was confirmed by PCR. All patients were at early stage and received routine chemotherapy with or without radiotherapy after surgical removal. All patients achieved complete remission with 24, 18 and 3 months follow-up, respectively. Primary thymic MALT lymphoma may be a rare distinctive lymphoma. It can be diagnosed by HE and immunohistochemical study and should be differentiated from reactive lymphoid proliferation, other types of lymphoma and mediastinal thymoma.

Pathology of Ocular Lesions Associated with Gas Supersaturation in White Seabass

Cultured juvenile white seabass Atractoscion nobilis (WSB) can suffer from intraocular emphysemas and exophthalmia in the hatchery environment. To identify the cause, two size-groups of WSB were exposed to five gas saturation levels, ranging from 98% to 122% total gas pressure (TGP), over a 96-h exposure period in 18 degrees C and 23 degrees C seawater. Histological examination revealed that the gross and subgross lesions associated with gas supersaturation included corneal and orbital emphysema, along with subretinal, optic nerve, and iridial hemorrhage. Corneal emphysema was the most prominent gross lesion, with the severity and prevalence increasing between size-groups and water temperatures as TGP increased. Following the same pattern was orbital emphysema, which affected more than 93% of the fish examined and caused hemorrhage in the subretinal space, around the optic nerve, in the iris, or a combination thereof. Iridial hemorrhage occurred in 91% of the fish examined and decreased significantly with fish size. The prevalence and severity of hemorrhage in the subretinal space increased significantly with TGP and fish size but not with temperature. Optic nerve hemorrhage was absent in small fish exposed at 18 degrees C but increased significantly with temperature and fish size. The reverse was true for the large fish.

Clinico-pathological studies of cattle naturally infected with Mycobacterium avium subspecies paratuberculosis in Khartoum State, Sudan

Four crossbred cows, 3-5 year- old, naturally infected with Mycobacterium avium subspecies paratuberculosis (MAP) were sacrificed and necropsied. Clinically, they showed profused diarrhoea, emaciation and rough coat with an area of alopecia on the tail. The most prominent macroscopic lesions were thickening, oedema and corrugation of the wall of small and large intestines. The mesenteric lymph nodes were enlarged and oedematous. Microscopically, all cows presented granulomatous enteritis. The inflammatory exudates varied from accumulation of lymphoid cells mixed with some epithelioid macrophages and giant cells to sheets of epithelioid macrophages intermingled with some lymphoid cells. The lymphatics in the submucosa of both the small and large intestines were dilatated and filled with pink homogenous proteinous materials. Acid-fast bacilli (AFB) were demonstrated in the infiltrating epithelioid macrophages and giant cells. Culture of inocula from the small and large intestines and the mesenteric lymph nodes of all animals showed small, round, smooth and glistening colonies 5-7 weeks following incubation in Herrold's Egg Yolk Medium at 37°C.

Importance of the C2, N7, and C8 Positions to the Mutagenic Potential of 8-Oxo-2′-deoxyguanosine with Two A Family Polymerases

8-Oxo-2'-deoxyguanosine (OdG) is a prominent DNA lesion produced from the reaction of 2'-deoxyguanosine (dG) with reactive oxygen species. While dG directs the insertion of only dCTP during replication, OdG can direct the insertion of either dCTP or dATP, allowing for the production of dG → dT transversions. When replicated by Klenow fragment-exo (KF-exo), OdG preferentially directs the incorporation of dCTP over dATP, thus decreasing its mutagenic potential. However, when replicated by a highly related polymerase, the large fragment of polymerase I from Bacillus stearothermophilus (BF), dATP incorporation is preferred, and a higher mutagenic potential results. To gain insight into the reasons for this opposite preference and the effects of the C2, N7, and C8 positions on OdG mutagenicity, single-nucleotide insertions of dCTP and/or dATP opposite dG, OdG, and seven of their analogues were examined by steady state kinetics with both KF-exo and BF. Results from these studies suggest that the two enzymes behave similarly and are both sensitive not only to steric and electronic changes within the imidazole ring during both dCTP and dATP incorporation but also to the presence of the C2-exocyclic amine during dATP incorporation. The difference in incorporation preference opposite OdG appears to be due to a somewhat increased sensitivity to structural perturbations during dCTP incorporation with BF. Single-nucleotide extensions past the resulting base pairs were also studied and were not only similar between the two enzymes but also consistent with published ternary crystallographic studies with BF. These results are analyzed in the context of previous biochemical and structural studies, as well as stability studies with the resulting base pairs.

High Glucose Induces Mitochondrial Morphology and Metabolic Changes in Retinal Pericytes

Mitochondrial dysfunction is known to play a role in retinal vascular cell loss, a prominent lesion of diabetic retinopathy. High glucose (HG) has been reported to induce mitochondrial fragmentation and dysfunction in retinal endothelial cells, contributing to apoptosis. In this study, the effects of HG on mitochondrial morphology, membrane potential, and metabolic changes and whether they could contribute to HG-induced apoptosis in retinal pericytes were investigated. Bovine retinal pericytes (BRPs) were grown in normal or HG medium for 7 days. Both sets of cells were double stained with mitochondrial membrane potential-independent dye and tetramethylrhodamine-ethyl-ester-perchlorate (TMRE) and imaged by confocal microscopy. The images were analyzed for average mitochondria shape, by using form factor and aspect ratio values, and membrane potential changes, by using the ratio between the red and green dye. BRPs grown in normal or HG medium were analyzed for transient changes in oxygen consumption and extracellular acidification with a flux analyzer and apoptosis by TUNEL assay. BRPs grown in HG media exhibited significant fragmentation of mitochondria and increased membrane potential heterogeneity compared with the BRPs grown in normal medium. Concomitantly, BRPs grown in HG showed reduced steady state and maximum oxygen consumption and reduced extracellular acidification. Number of TUNEL-positive pericytes was increased in HG condition as well. In HG condition, mitochondria of retinal pericytes display significant fragmentation, metabolic dysfunction, and reduced extracellular acidification. The detrimental effects of HG on mitochondrial function and cellular metabolism could play a role in the accelerated apoptosis associated with the retinal pericytes in diabetic retinopathy.

Chemotherapy Versus Surgery in Primary B-Cell Lymphoma Masquerading as Klatskin Tumor—A Diagnostic and Therapeutic Dilemma

Primary lymphoma in the region of the liver bed mimicking hilar cholangiocarcinoma or Klatskin tumor is very rare. A patient presented with obstructive jaundice along with right upper quadrant pain, weight loss, and decreased appetite. Apart from altered liver function, her lactate dehydrogenase was significantly elevated, and imaging studies showed prominent lesion close to the liver bed with localized lymphadenopathy. The diagnosis ultimately reached at by biopsy and immunohistochemical staining was diffuse large B-cell lymphoma. Such cases are very infrequent, but demand awareness. The sooner the diagnosis can be reached by minimally invasive procedures, the earlier chemotherapy with rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone can be initiated and laparotomy can be avoided as chemotherapy is the mainstay of treatment, even in the presence of jaundice.

POEMS syndrome with prominent acute axonal lesions

Polyneuropathy is a common presenting component of POEMS syndrome whose symptoms are attributed to an overproduction of vascular endothelial growth factor (VEGF). We report two female patients with POEMS syndrome presenting as a severe predominantly axonal neuropathy. A nerve biopsy was performed for these patients; pathological data confirmed unusual numerous acute axonal lesions associated with other classical signs of POEMS syndrome. POEMS syndrome is usually associated with demyelinating neuropathy (and secondary axonal loss); however, prominent axonal neuropathy (with acute axonal lesions on nerve biopsy) can also be observed in this disease. These observations illustrate the heterogeneity of peripheral nervous system involvement in POEMS syndrome.

An unusual clinical presentation of pemphigus herpetiformis with marked response to dapsone

To the Editor: A 39-year-old African American woman presented to our dermatology clinic with a pruritic blistering eruption of 2 years' duration. The eruption started on the face and subsequently generalized to the trunk and extremities. The physical examination revealed scattered excoriated hyperpigmented patches and thin plaques over her face, trunk, and arms. The most prominent lesions were over bilateral pretibial surfaces, showing well-demarcated, hyperpigmented thin plaques intermixed with intact blisters and superficial erosions, reminiscent of a minimally scarring stage of pretibial dystrophic epidermolysis bullosa (Fig 1, A).