Imaging of acute mesenteric ischemia using multidetector CT and CT angiography in a porcine model

Acute mesenteric ischemia, a frequently lethal disease, requires prompt diagnosis and intervention for favorable clinical outcomes. This goal remains elusive due, in part, to lack of a noninvasive and accurate imaging study. Traditional angiography is the diagnostic gold standard but is invasive and costly. Computed tomography (CT) is readily available and noninvasive but has shown variable success in diagnosing this disease. The faster scanning time of multidetector row CT (M.D.CT) greatly facilitates the use of CT angiography (CTA) in the clinical setting. We sought to determine whether M.D.CT-CTA could accurately demonstrate vascular anatomy and capture the earliest stages of mesenteric ischemia in a porcine model. Pigs underwent embolization of branches of the superior mesenteric artery, then imaging by M.D.CT-CTA with three-dimensional reconstruction protocols. After scanning, diseased bowel segments were surgically resected and pathologically examined. Multidetector row CT and CT angiography reliably defined normal and occluded mesenteric vessels in the pig. It detected early changes of ischemia including poor arterial enhancement and venous dilatation, which were seen in all ischemic animals. The radiographic findingsd—compared with pathologic diagnosesd—predicted ischemia, with a positive predictive value of 92%. These results indicate that M.D.CT-CTA holds great promise for the early detection necessary for successful treatment of acute mesenteric ischemia. Presented at the Forty-Sixth Annual Meeting of The Society for Surgery of the Alimentary Tract, Chicago, Illinois, May 14–18, 2005 (oral presentation). Supported by the Karin Grunebaum Research Fellowship, Harvard Medical School (D.E.R.), the German Research Fellowship, German Research Foundation STR 690/1-1 (O.S.), and the Phillip H. Meyers Grant from the Society of Gastrointestinal Radiologists (S.P.T.).     

Modafinil augmentation of selective serotonin reuptake inhibitor therapy in MDD partial responders with persistent fatigue and sleepiness.

BACKGROUND: Partial response, no response, or residual symptoms following antidepressant therapy is common in clinical psychiatry. This study evaluated modafinil in patients with major depressive disorder (MDD) who were partial responders to adequate selective serotonin reuptake inhibitor (SSRI) therapy and excessive sleepiness and fatigue. METHODS: This retrospective analysis pooled the data of patients (18-65 yrs) who participated in two randomized, double-blind, placebo-controlled studies of modafinil (6-week, flexible-dose study of 100-400 mg/day or 8-week, fixed-dose study of 200 mg/day) plus SSRI therapy. Patients (n=348) met criteria for several residual symptoms (Epworth Sleepiness Scale [ESS] score>or=10; 17-item Hamilton Depression Scale [HAM-D] score between 4 and 25; and Fatigue Severity Scale [FSS] score>or=4). RESULTS: Compared to placebo, modafinil augmentation rapidly (within 1 week) and significantly improved overall clinical condition (Clinical Global Impression-Improvement), wakefulness (ESS), depressive symptoms (17-item HAM-D), and fatigue (FSS) (p<.01 for all). At final visit, patients receiving modafinil augmentation experienced statistically significant improvements in overall clinical condition, wakefulness, and depressive symptoms. Modafinil was well tolerated in combination with SSRI. CONCLUSIONS: Results of this pooled analysis provide further evidence suggesting that modafinil is an effective and well-tolerated augmentation therapy for partial responders to SSRI therapy, particularly when patients continue to experience fatigue and excessive sleepiness.     

A multicenter clinical trial of gadolite oral suspension as a contrast agent for MRI

The purpose of this study was to assess the effectiveness and safety of Gadolite Oral Suspension as a gastrointestinal (GI) contrast agent for MRI in a phase II and two phase III multicenter clinical trials. Gadolite was administered to 306 patients with known or suspected abdominal and/or pelvic disease. MRI with T1- and T2-weighted sequences was performed before and after ingestion. Efficacy was evaluated by having two masked readers rate the certainty of their MR diagnosis (0 = uncertain, 1 = probable, 2 = definite) on randomly presented pre- and post-Gadolite Oral Suspension enhanced images. Principal investigators also evaluated the images and established the final diagnosis. Vital signs, clinical chemistries, and adverse events were documented. Blood and urine samples were analyzed for gadolinium content to determine whether Gadolite Oral Suspension was absorbed systemically. Certainty in MR diagnosis increased significantly (P < .001) for both blinded readers between pre- and post-Gadolite images (.49–1.18 for reader 1; .46–1.53 for reader 2). Sensitivity, specificity, and accuracy also increased for both masked readers. No gadolinium was detected in blood or urine samples. There were no serious adverse events and no apparent drug-related trends in mean vital signs or laboratory values. Gadolite is a highly effective, safe, and well tolerated contrast agent for clinical use with MRI.     

Cervical Cancer with Paraaortic Metastases: Significance of Residual Paraaortic Disease after Surgical Staging

Cervical carcinoma frequently metastasizes to the paraaortic region, necessitating extended field radiotherapy to effect a cure. As imaging modalities are unreliable in identifying all cases of paraaortic nodal metastases (PAN), surgical staging is often utilized prior to radiotherapy. This study was aimed at identifying factors predictive of survival in women with cervical carcinoma and paraaortic metastases. In particular, survival based on extent of paraaortic disease was examined. The study group consisted of 43 women (stages IB–IVB) identified between 1982 and 1993 who were treated with extended field radiation for cervical carcinoma with histologically confirmed paraaortic metastases. The estimated 5-year survival for the study population was 24% with a median survival of 18 months. Pelvic tumor size had a significant impact on survival with the median survival being 34 months if the primary lesion was <6 cm compared to 14 months if ≥6 cm (P= 0.01). Eight of the 26 (31%) women without residual PAN disease after surgical staging remain alive and disease free (mean follow-up, 74 months). In contrast, only 1 of the 17 (6%) women with gross residual PAN is alive 71 months after treatment (P= 0.05). However, a comparison of Kaplan–Meier survival curves did not show a statistically significant advantage to the surgical excision of grossly involved PAN (P= 0.98). Although long-term survival among women with grossly involved, unresected paraaortic metastases is uncommon, further study is necessary to elucidate the role of surgical excision of bulky aortic disease in women with cervical cancer.     

Leukemoid reaction: a diagnostic clue in metastatic carcinoma mimicking classic Hodgkin lymphoma

We report on 2 patients who were initially suspected to have classic Hodgkin lymphoma because of lymphadenopathy and the presence of Reed-Sternberg-like cells. Both patients had an associated leukemoid reaction (using a threshold leukocyte count of 50 000/microL) and were eventually diagnosed with metastatic carcinoma. Disseminated carcinoma can mimic Hodgkin lymphoma clinically, radiologically, and histologically. Reed-Sternberg-like cells may be found in carcinomas, and they represent a particularly challenging diagnostic pitfall for the unwary. When these cells lead to a suspicion of Hodgkin lymphoma, the presence of a leukemoid reaction should prompt the pathologist to question the diagnosis. Misdiagnosis can be avoided by the use of cytokeratin whenever a leukemoid reaction is present in a suspected case of Hodgkin lymphoma.     

Neuropathogenesis of Chimeric Simian/Human Immunodeficiency Virus infection In Pig-tailed and Rhesus Macaques

We recently reported that a chimeric simian/human immunodeficiency virus (SHIV_KU-1) developed in our laboratory caused progressive depletion of CD4⁺T lymphocytes and AIDS within 6 months of inoculation into pig-tailed macaques (M.nemestrina). None of the pig-tailed macaques showed productive SHIV infection in the central nervous system (CNS). In this report, we show that by further passage of the pathogenic virus in rhesus macaques [M. mulatta], we have derived a new strain of SHIV (SHIV_KU-2) that has caused AIDS and productive CNS infection in 3 of 5 rhesus macaques infected with the virus. Productive replication of SHIV in the CNS was clearly shown by high infectivity titers and p27 protein levels in brain homogenates, and in 2 of the 3 rhesus macaques this was associated with disseminated, nodular, demyelinating lesions, including focal multinucleated giant cell reaction, largely confined to the white matter. These findings were reminiscent of HIV-1 associated neurological disease, and our immunohistochemical and in situ hybridization data indicated that the neuropathological lesions were associated with the presence of SHIV-specific viral antigens and nucleic acid respectively. However, the concomitant reactivation of opportunistic infections in these macaques suggested that such pathogens may have influenced the replication of SHIV in the CNS, or modified the neuropathological sequelae of SHIV infection in the rhesus species, but not in pig-tailed macaques. Our findings in the two species of macaques highlight the complexities of lentiviral neuropathogenesis, the precise mechanisms of which are still elusive.