In vivo expression of thrombospondin-1 suppresses the formation of peritoneal adhesion in rats.

BACKGROUND: Formation of intraperitoneal adhesions is one of the major complications after abdominal surgery, which may lead to bowel obstruction. Thrombospondin 1 (TSP-1) is an extracellular matrix modulating glycoprotein during tissue regeneration and collagen deposition. AIM: To evaluated the therapeutic potential of overexpressed TSP-1 in suppressing pelvic adhesion formations in rat models. METHODS: Pelvic adhesion was induced in anesthetized rats by laparotomy cecal abrasion. The animals were randomly assigned to treatment of local application with Seprafilm (an antiadhesive bioresorbable membrane) or adenoviral vectors encoding mouse TSP-1 (AdTSP-1) on the surfaces of the injured cecum. The severity of the peritoneal adhesions was evaluated by blinded observers 14 d later. RESULTS: Compared with control (no treatment) group, the application of Sperafilm significantly reduced the formation of adhesion band, and local administration of AdTSP-1 on the injured cecum the also attenuated the severity of peritoneal adhesion score. However, systemic delivery of AdTSP-1 did not affect the formation of adhesion. CONCLUSION: We conclude that therapeutic approaches in inducing regional overexpression of TSP-1 may serve as alternative treatment strategies for preventing postoperative peritoneal adhesion.

EBV-associated Burkitt lymphoma in Taiwan is not age-related.

This study retrospectively investigated 54 cases of sporadic Burkitt lymphoma in Taiwan with histopathology review, immunohistochemistry, Epstein-Barr virus (EBV) in situ hybridization (EBER) and fluorescence in situ hybridization (FISH). The great majority revealed typical immunophenotype and 89% (47/53) cases expressed myc protein. EBER was positive in 20% (11/54) of cases, more frequently with nodal presentation, but not significantly associated with age (pediatric vs. adult), abdominal vs. extra-abdominal presentation or overall survival (OS). MYC and IGH were rearranged in 94% (46/49) and 85% (41/48) of cases, respectively. The concordance rate between myc expression and MYC translocation was 83% (40/48). By univariate analysis, OS was statistically associated with age, with or without chemotherapy, central nervous system (CNS) involvement, CNS prophylaxis and leukemic transformation, but not gender, nodal vs. extranodal involvement, stage, immunohistochemistry, EBER, myc expression, MYC translocation or radiotherapy. By multivariate analysis, CNS involvement at presentation and administration of chemotherapy were statistically associated with OS.

Angioimmunoblastic T-cell lymphoma in Taiwan shows a frequent gain of ITK gene.

Angioimmunoblastic T-cell lymphoma (AITL) is an aggressive peripheral T-cell lymphoma (PTCL) of follicular helper T-cell origin and is rare in Taiwan. There are overlapping features of AITL and peripheral T-cell lymphoma with a follicular growth pattern (PTCL-F). Around one fifth of PTCL-F exhibits t(5;9)(q33;q22)/ITK-SYK chromosomal translocation, which is essentially absent in AITL. We retrospectively investigated 35 cases of AITL from Taiwan with histopathology review, immunohistochemistry, in situ hybridization for Epstein-Barr virus (EBV) and fluorescence in situ hybridization (FISH) for t(5;9)(q33;q22)/ITK-SYK and correlated the results with overall survival. Twenty-six cases of not otherwise specified PTCL (PTCL-NOS) were also examined by FISH for comparison. Most AITL patients were male (69%) and elderly (median age at 67 years) with frequent bone marrow involvement (53%), high Ann Arbor stages (77%), and elevated serum lactate dehydrogenase (68%). Most cases (80%) showed a typical CD4+/CD8- phenotype and in 90% cases there were scattered EBV-positive B-cells (less than 10% cells). None of these cases showed t(5;9)(q33;q22)/ITK-SYK translocation by FISH. Gain of ITK and SYK gene was identified in 38% and 14% tumors, respectively, but both were not associated with overall survival. Performance status < 2 was associated with a better outcome but not the other clinicopathological factors. All PTCL-NOS cases were negative for ITK-SYK translocation with similar rates (38% and 12%, respectively) of gains at ITK and SYK loci as that of AITL. In this so far the largest series of AITL from Taiwan, we reported the clinicopathological features and FISH findings on ITK and SYK genes. We confirmed the absence of t(5;9)(q33;q22)/ITK-SYK translocation, which may serve as an additional differential diagnostic tool from PTCL-F when present. PTCL-NOS shared a similar pattern of ITK and SYK gains with AITL. More studies are warranted to elucidate the roles of SYK and ITK and other genes in the lymphomagenesis of AITL in Taiwan.

Neurophysiological and histopathological evaluation of low-dose radiation on the cauda equina and postlaminotomy fibrosis: an experimental study in the rat.

STUDY DESIGN: We evaluated the electrophysiological changes to the cauda equina after low-dose external irradiation in a postlaminotomy fibrosis model in rats. OBJECTIVE: To clarify the immediate and long-term electrophysiological responses of antifibrotic radiation therapy in a fibrosis model. SUMMARY OF BACKGROUND DATA: Low-dose perioperative radiation therapy inhibits scar formation. However, its efficacy for preventing fibrosis-induced compressive neuropathy and its potential adverse effect on underlying neural structures have not been studied. METHODS: Twenty-four rats were placed in 3 groups of 8: group I, sham operation (laminar exposure alone) with a single fraction of 700 cGy external irradiation given using a 9-MeV electron beam 24 hours postsurgery; group II, left L5 hemilaminectomy (laminotomy) alone; and group III, left L5 hemilaminectomy with the same radiation protocol as group 1. We recorded mixed-nerve-elicited somatosensory-evoked potentials (M-SSEP)- and dermal (D)-SSEP at the thoracolumbar junction, and L1-L2 interspinous ligament after percutaneously stimulating the posterior tibial nerve at the bilateral medial ankle and L5 dermatomal fields. We compared the potentials recorded immediately before, 30 minutes, 2 weeks, and 1, 2, and 3 months after surgery on the operated and nonoperated sides. We used gross dissection and histologic sections to evaluate the degree of perineural fibrosis and walking-track analysis for neurologic evaluation. RESULTS: Pre- and postoperative (30 minutes and 2 weeks) M- and D-SSEP were not statistically different. In group II, the relative amplitude of D-SSEP (elicited from 5 dermatomes) 1, 2, and 3 months postsurgery was lower; however, the M-SSEP in all groups and D-SSEP of groups I and III remained constant. Histologic evaluation of radiation efficacy showed that the frequency and extent of peridural fibrosis was consistently lower in group II than in group III. CONCLUSION: Low-dose irradiation reduced peridural fibrosis and prevented fibrosis-induced radiculopathy. The radiation caused no adverse neuropathic complications.

Histopathology and immunohistochemistry in distinguishing Burkitt lymphoma from diffuse large B-cell lymphoma with very high proliferation index and with or without a starry-sky pattern: a comparative study with EBER and FISH.

Burkitt lymphoma (BL) is characterized by c-myc translocation and CD10+/bc-2-/bcl-6+ with a very high Ki-67 proliferation index (PI). Occasional diffuse large B-cell lymphomas may exhibit a very high PI with or without a starry-sky pattern (DLBCL-HPSS). We compared 28 consecutive BL and 16 DLBCL-HPSS cases in immunocompetent Taiwanese diagnosed by histopathologic examination and immunophenotyping and compared the results with results for Epstein-Barr virus-encoded messenger RNA (EBER) and fluorescence in situ hybridization (FISH). There were statistically significant differences in the expression of CD10 (28/28 vs 1/16), bcl-2 (3/28 vs 11/16), MUM1 (5/28 vs 15/16), a PI of 95.0% or more (27/28 vs 2/16), and combined CD10+/bcl-2-/bcl-6+ (24/28 vs 1/16) between BLs and DLBCL-HPSSs. Of the BLs, 7 (25%) of 28 and 26 (96%) of 27 were positive for EBER and c-myc rearrangement as compared with 0 of 16 and 1 (7%) of 15 DLBCL-HPSSs, respectively. We can confidently distinguish BL from DLBCL-HPSS by using histopathologic and immunohistochemical (CD10, bcl-2, bcl-6, Ki-67) methods without the aid of EBER and FISH in the great majority of cases.

Spinal somatosensory evoked potential to evaluate neurophysiologic changes associated with postlaminotomy fibrosis: an experimental study.

STUDY DESIGN: We evaluated electrophysiologic changes of the cauda equina after lumbar laminotomy in rats. OBJECTIVE: To clarify immediate and long-term electrophysiologic and neurologic responses in an experimental postlaminotomy animal fibrosis model. SUMMARY OF BACKGROUND DATA: Postspinal surgery-induced epidural fibrosis is assessed using either Gadolinium- enhanced magnetic resonance imaging (MRI) or intraoperative observations. In experimental animal models mimicking this complication, many approaches are used: advanced imaging (computed tomography, CT; and MRI), functional observations, biomechanical techniques, and histologic examinations. However, no study has reported the substantial neurophysiologic changes of the cauda equina in such a model. METHODS: Rats were given a sham operation (laminar exposure only), a left L5 hemilaminotomy alone, or a left L5 hemilaminotomy with extradural topical collagen. Mixed-nerve-elicited somatosensory-evoked potentials (M-SSEPs) and dermatomal (D)-SSEPs were recorded at the thoracolumbar junction after percutaneous stimulation of the posterior tibial nerve at the bilateral medial ankles and the L5 dermatomal field, respectively. Potentials recorded on the operated and nonoperated sides before surgery and then 30 minutes, 2 weeks, and 1, 2, and 3 months after surgery were compared. Walking track and thermal hyperalgesia test results and a final histologic analysis of perineural fibrosis were correlated. RESULTS: Electrical stimulation yielded reproducible responses in all rats on all tests. Preoperative and postoperative measurements showed no statistically significant differences in M-SSEP or D-SSEP. Postoperative D-SSEPs in both experimental groups showed significant reductions in relative amplitude, but the M-SSEPs of all groups and D-SSEPs of the control groups remained constant. CONCLUSION: SSEP is valuable for detecting electrophysiologic changes after laminotomy fibrosis, but acceptable accuracy requires proper stimulation and recording settings. D-SSEP monitoring provided reliable, useful information about the functional integrity of the cauda equina in this animal model. We recommend D-SSEP monitoring as a supplemental tool for quantifying the effect of postlaminotomy fibrosis on neuropathy.

Natural killer cell lymphoma of small intestine with features of enteropathy but lack of association with celiac disease.

A primary small intestinal natural killer (NK) cell lymphoma with pathologic features of enteropathy but lack of association with celiac disease is reported. A 37-year-old man presented with tarry stool, coffee-ground vomitus, and mild fever. He did not have chronic diarrhea or malabsorption. Segmental resection of the duodenum and jejunum showed multicentric transmural infiltration by medium-sized lymphoma cells expressing CD3, CD8, cytotoxic granules, and Epstein-Barr virus by in situ hybridization. The nontumorous mucosa away from the main tumor revealed enteropathy with villous blunting and increased intraepithelial lymphocytes sharing the same immunophenotype as the lymphoma cells. Both lymphoma and nontumorous areas were germline for T-cell receptor-gamma and immunoglobulin heavy chain gene rearrangement. Serologic test by ELISA was negative for anti-transglutaminase. The patient died of repeated gastrointestinal bleeding and sepsis at 2 months. Differential diagnosis of this unique nasal-type NK-cell lymphoma with enteropathy-associated T-cell lymphoma is discussed.

Emergence of Klebsiella pneumoniae isolates producing inducible DHA-1 beta-lactamase in a university hospital in Taiwan.

Ten nonrepetitive clinical isolates of Klebsiella pneumoniae exhibiting an unusual inducible beta-lactam resistance phenotype were identified between January 1999 and September 2001 in a university hospital in Taiwan. In the presence of 2 micro g of clavulanic acid, the isolates showed a one to four twofold concentration increase in the MICs of ceftazidime, cefotaxime, and aztreonam but remained susceptible to cefepime (MICs,