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Coleman RL, Burke TW, Morris M, Eifel PJ, Hallum AV, Wallace S, Tornos C. Intraoperative radiographs to confirm the adequacy of lymph node resection in patients with suspicious lymphangiograms. Gynecol Oncol 1993; 51:362-7. [PMID: 8112646 DOI: 10.1006/gyno.1993.1304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Between June 1991 and October 1992, we used presurgery lymphangiograms and intraoperative radiographs to identify and remove suspicious nodes in the pelvic and para-aortic chains of 19 patients with bulky pelvic cancers. Surgery comprised extraperitoneal exploration using a midline vertical or paramedian "J" incision. After grossly enlarged nodes were removed, an intraoperative anterior-posterior (AP) abdominal radiograph was obtained. The exposure field approximated the 24-hr delay AP LAG radiograph. Both films were compared in the operating room to confirm removal of abnormal nodes. Initial resection removed all suspicious nodes in 16 of 19 cases. Additional dissection resulted in successful node excision in the other 3 patients. Most of these "missed" nodes were behind or between vessels. The median number of nodes sampled was 15 (range 2-47). Bilateral sampling was performed in 15 cases. Metastatic tumor was present in 14 patients (74%) who had from 1 to 8 positive nodes. Of the 5 negative specimens, all contained lipogranulomata; two had extensive fatty replacement, 2 contained Müllerian inclusions, and 1 had reactive follicular hyperplasia which could be accountable for the radiographic abnormalities. Extracapsular extension was noted in 12 of 14 metastatic samplings. Radiotherapeutic treatment planning was then tailored to lymph node status and the location of positive nodes. Combined use of preoperative LAG and intraoperative films is useful in ensuring that complete resection of abnormal nodes has been accomplished. Whether removal of gross lymph node metastases enhances survival requires further study.
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Kanazawa S, Wright KC, Kasi LP, Charnsangavej C, Wallace S. Preliminary experimental evaluation of temporary segmental hepatic venous occlusion: angiographic, pathologic, and scintigraphic findings. J Vasc Interv Radiol 1993; 4:759-66. [PMID: 8280997 DOI: 10.1016/s1051-0443(93)71969-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
PURPOSE Pigs were used to evaluate temporary segmental hepatic venous occlusion as a means of improving the selective delivery of therapeutic agents within the liver. MATERIALS AND METHODS Hepatic angiography and scintigraphy were performed alone and in combination with hepatic venous occlusion. RESULTS Arteriograms obtained during venous obstruction demonstrated a greater number of peripheral arterial branches in the occluded area compared with the nonoccluded areas. A prolonged hepatogram showing hepatofugal opacification of the portal branches was observed in the occluded area. Microscopically, mild congestion of the sinusoids and central veins was seen immediately after 60-minute occlusion, but these changes were not evident 2 hours after balloon deflation. Severe congestion and focal hemorrhage were found in the occluded segment of the liver 2 hours after 90-minute venous occlusion. When the right or left hepatic vein was occluded during hepatic arterial infusion of technetium-99m macroaggregated albumin, there was a significant (P < or = .05) increase in the amount of radioactivity measured in the obstructed segment and a significant (P < or = .05) decrease in that found in the nonoccluded regions. CONCLUSION These results indicate that temporary segmental hepatic vein occlusion is safe for up to 60 minutes and may be clinically applicable as a means of improving the therapeutic index of agents within the liver when they are administered via concomitant hepatic arterial infusion.
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Leitch GJ, He Q, Wallace S, Visvesvara GS. Inhibition of the spore polar filament extrusion of the microsporidium, Encephalitozoon hellem, isolated from an AIDS patient. J Eukaryot Microbiol 1993; 40:711-7. [PMID: 8292991 DOI: 10.1111/j.1550-7408.1993.tb04463.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Spores of the microsporidian parasitic protozoan Encephalitozoon hellem were purified and incubated at 37 degrees C in a solution with an electrolyte composition similar to that of mammalian extracellular fluid, and in solution in which the calcium had been replaced with 0.2 mM EGTA. Polar filament extrusion (germination) was monitored by both scanning electron microscopy and light microscopy. Germination was pH-dependent, with optima at pH 7.4 and 9.5, and was significantly greater in the presence of medium calcium. Hydrogen peroxide caused a concentration-dependent increase in germination that was also reduced in a calcium-free medium. Four agents were found to inhibit spontaneous and H2O2-stimulated polar filament extrusion: the microfilament disrupter, cytochalasin D; the microtubule disrupter, demecolcine; the calcium channel blocker, nifedipine; and the antifungal agent, itraconazole. These results are consistent with the existence of a calcium-channel-mediated step, and requirements for an F-actin- and for a tubulin-containing element in the germination process of the spore of this parasite. Nifedipine, cytochalasin D and itraconazole all have different sites of action and were therefore able to potentiate one another when used in paired combination to inhibit germination.
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Jones DV, Patt YZ, Ajani JA, Abbruzzese J, Carrasco CH, Charnsangavej C, Levin B, Wallace S. A phase I-II trial of mitoxantrone by hepatic arterial infusion in patients with hepatocellular carcinoma or colorectal carcinoma metastatic to the liver. Cancer 1993; 72:2560-3. [PMID: 8402476 DOI: 10.1002/1097-0142(19931101)72:9<2560::aid-cncr2820720908>3.0.co;2-e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND Mitoxantrone is an anthraquinone derivative that has demonstrated encouraging preclinical and clinical activity against a variety of human carcinoma cell lines and malignancies. Three Phase II studies of systemically administered mitoxantrone in patients with colorectal carcinoma failed to demonstrate any therapeutic activity, as did four Phase II studies of intravenous mitoxantrone in hepatocellular carcinoma. Two additional trials demonstrated limited activity when administered intravenously to patients with hepatocellular carcinoma. However, because this drug exhibits a steep dose-response curve, a Phase I-II trial of mitoxantrone by hepatic arterial infusion was initiated. METHODS Patients with hepatocellular carcinoma and metastatic colorectal carcinoma with liver only or liver-predominant disease were eligible for therapy. All patients underwent the placement of a percutaneous hepatic arterial catheter before each course of therapy, and the first cohort of patients was treated at 10 mg/m2/course on day 1 on a 28-day cycle. Dosages were escalated in increments of 2 mg/m2/course based on side effects and tolerance. RESULTS Twenty-eight patients with bidimensionally measurable unresectable, liver-predominant disease were entered into this trial. The therapy was well tolerated, with only 5 courses of 55 being complicated by neutropenia and none associated with fever. Only one patient required a dosage reduction on the basis of toxicity (neutropenia). No complete or partial responses were observed. CONCLUSION These data are consistent with a lack of therapeutic activity of mitoxantrone when administered by hepatic arterial infusion for the treatment of hepatocellular carcinoma or metastatic colorectal cancer.
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Yasumori K, Mahmoudi N, Wright KC, Wallace S, Gianturco C. Placement of covered self-expanding metallic stents in the common bile duct: a feasibility study. J Vasc Interv Radiol 1993; 4:773-8. [PMID: 8280999 DOI: 10.1016/s1051-0443(93)71971-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
PURPOSE Gianturco self-expanding metallic stents have been useful in cases of benign biliary stenoses; however, the stents have not worked well in the presence of intraluminal tumor because of tumor growth between the wire struts. Stents were covered with polymeric membranes, which may prevent tumor ingrowth, and the feasibility of using these covered stents in the common bile duct was studied in healthy adult dogs. MATERIALS AND METHODS Initially, stents (10 x 6 mm) covered with polycaprolactone (PCL), segmented polyether polyurethane (SPP), and silicone were placed in the common bile duct of dogs and were followed up for 3-12 months. Subsequently, four types of modified silicone-covered stents were evaluated. Rough-surface, small-diameter (3-mm), half-covered, and tapered stents were placed and followed up for 3 months. RESULTS In the initial study, the SPP and silicone membranes remained intact, but the PCL covering broke in all dogs. In all but two dogs, luminal narrowing caused by varying degrees of papillary mucosal hyperplasia at both ends of the stent was observed. In the subsequent study, mucosal hyperplasia was considerably reduced by using half-covered stents and was virtually eliminated with tapered stents. All small-diameter stents migrated into the bowel. CONCLUSION These studies suggest that tapered Gianturco self-expanding stents covered with silicone may be useful in the biliary tract in cases of intraluminal tumor.
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North LB, Wallace S, Lindell MM, Jing BS, Fuller LM, Allen PK. Lymphography for staging lymphomas: is it still a useful procedure? AJR Am J Roentgenol 1993; 161:867-9. [PMID: 8372776 DOI: 10.2214/ajr.161.4.8372776] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE The purpose of this study was to determine the current value of lymphography in a series of previously untreated patients with Hodgkin's and non-Hodgkin's lymphoma seen at the M. D. Anderson Cancer Center over a 1-year period. MATERIALS AND METHODS From September 1989 through August 1990, 313 previously untreated patients with lymphoma were seen at our institution. In 221 of these, lymphography and CT were performed for abdominal staging. These studies were reviewed to determine if the examinations were complementary, or if the results of one or the other changed the staging in a significant number of patients. Staging was based on clinical findings, as laparotomies are rarely performed at this time. RESULTS Lymphograms were abnormal and CT scans were normal in two patients with Hodgkin's disease and in two with non-Hodgkin's lymphomas. Biopsy proof of nodal disease was not available for any of these, but the nodes did not change after therapy in three patients. The other patient was seropositive for HIV, and HIV disease itself can cause nodal abnormalities. In one patient with Hodgkin's disease and 12 with non-Hodgkin's lymphoma, lymphograms were normal and CT scans were abnormal, showing enlarged nodes and/or abnormal architecture. CT scans obtained after therapy showed regression of nodal and extranodal masses. CONCLUSION It was concluded that lymphographic findings did not significantly contribute to staging in these patients. This departure from previous experience may be due to improved state-of-the-art CT. In addition, the use of a combination of chemotherapy and radiation therapy to treat the lymphomas has increased, diminishing the need for detection of subtle nodal changes.
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Maguire J, Madigan R, Wallace S, Leppanen R, Draper V. Intraoperative long-latency reflex activity in idiopathic scoliosis demonstrates abnormal central processing. A possible cause of idiopathic scoliosis. Spine (Phila Pa 1976) 1993; 18:1621-6. [PMID: 8235841 DOI: 10.1097/00007632-199309000-00009] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Segmental reflex regulation in 37 patients with idiopathic scoliosis and 8 patients with nonidiopathic scoliosis was studied by recording evoked reflex muscle potentials from four muscle groups in each lower extremity during partial neuromuscular blockade. Effects on reflex activity mediated through descending systems arising in the brain stem were investigated by recording from proximal-distal and flexor-extensor muscles. Ipsilateral and contralateral long-latency complex polysynaptic activity was present in all 37 patients with idiopathic scoliosis. This reflex activity was absent in eight nonidiopathic scoliosis patients. Long-latency reflex activity may represent segmental disinhibition. The presence of long-latency reflex activity in patients with idiopathic scoliosis and the absence of this activity in nonidiopathic scoliosis patients with curves of equal magnitude demonstrates that the curve per se is not responsible for the activity. This would imply that abnormal reflex processing may play a role in the development of the spinal deformity in patients with idiopathic scoliosis.
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Pavcnik D, Wright KC, Wallace S. Monodisk: device for percutaneous transcatheter closure of cardiac septal defects. Cardiovasc Intervent Radiol 1993; 16:308-12. [PMID: 8269428 DOI: 10.1007/bf02629163] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The Monodisk, a device to facilitate percutaneous closure of cardiac septal defects, was developed and tested in vitro and in vivo. Atrial septal defects (8-10 mm) were created in five dogs using transcatheter techniques. The defects were then closed with the Monodisk. The device was easily and successfully fixed in place in all dogs. The efficacy of the device was determined radiographically. No shunting of contrast medium was observed in any case. Animals were followed for 6 months. Results showed good biocompatibility and several advantages of the device: it requires only a simple one-step placement procedure; it utilizes a small delivery system; it is easy to place and detach; it is self-centering and stable; and it can be repositioned or retrieved prior to detachment. Its possible clinical applications include correction of atrial septal defects, ventricular septal defects, patent ductus arteriosus, as well as creating an aortopulmonary window.
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Wallace S, Gullan R. Mild head injury: Guideliners should be flexible. BMJ : BRITISH MEDICAL JOURNAL 1993. [DOI: 10.1136/bmj.307.6901.447-c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Mavligit GM, Pollock RE, Evans HL, Wallace S. Durable hepatic tumor regression after arterial chemoembolization-infusion in patients with islet cell carcinoma of the pancreas metastatic to the liver. Cancer 1993; 72:375-80. [PMID: 8391377 DOI: 10.1002/1097-0142(19930715)72:2<375::aid-cncr2820720211>3.0.co;2-d] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND Islet cell carcinoma of the pancreas is a neuroendocrine tumor often presenting with left upper quadrant mass and radiographic evidence of liver metastases. Because survival among these patients is determined largely by the pace of metastatic events in the liver, significant palliation may be achieved by regional hepatic therapy. METHODS Five patients with islet cell carcinoma of the pancreas metastatic to the liver (four nonfunctional, one gastrin producing), were treated by hepatic arterial chemoembolization-infusion consisting of a mixture of polyvinyl alcohol sponge (150 mg) and cisplatin (150 mg) followed by 2-hour intraarterial infusion of vinblastine (10 mg/m2). Each patient received two such treatments, 1 month apart, requiring 3 to 6 days of hospital admission. RESULTS Significant tumor regression (> 50%) was observed in four of five patients, lasting from 8 to 44 months. Toxicity was limited to right upper quadrant pain, paralytic ileus requiring nasogastric suction for 24 to 72 hours, transient, mild bilirubinemia and liver enzyme elevation, hypomagnesemia and hypokalemia, and occasionally, moderate, self-limiting granulocytopenia. CONCLUSIONS This preliminary, albeit limited, experience with hepatic chemoembolization-infusion in patients with islet cell carcinoma metastatic to the liver emphasizes the high incidences of durable tumor regression that can be achieved with minimal iatrogenic intervention.
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Wright KC, Dobben RL, Magal C, Ogawa K, Wallace S, Gianturco C. Occlusive effect of metallic stents on canine ureters. Cardiovasc Intervent Radiol 1993; 16:230-4. [PMID: 8402785 DOI: 10.1007/bf02602966] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A three-part study, with successive modifications based on preceding results, was conducted to evaluate ureteral placement of metallic stents. Gianturco self-expanding (10 mm and 4 mm diameter) and balloon-expanded (4 mm diameter) metallic stents were placed in normal and stenotic canine ureters. No migration or ureteral perforation occurred during the follow-up of 10 mm stents. Varying degrees of hydronephrosis and hydroureter were found on all 1-week pyelograms. At 4 weeks, complete occlusion of the stented ureter was noted in all cases because of mucosal hyperplasia around the stent wires. To prevent this reaction, 4 mm self-expanding stents constructed of smaller wire that was uncoated or coated with either Teflon or poly-urethane were tested in five dogs. In all cases, results were similar to those obtained with the larger prostheses. Finally, 4 mm balloon-expanded stents were placed in a normal ureter of three dogs. In one dog, the stent migrated out of the ureter. No migration or ureteral perforation occurred in the two remaining dogs. In these animals, mucosal hyperplasia and complete ureteral occlusion occurred 6 and 8 weeks after placement. Therefore, ureteral placement of Gianturco self-expanding as well as balloon-expanded metallic stents leads to occlusion of the ureter instead of maintaining its patency. Stents, therefore, may be useful as ureteral occlusion devices.
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Wallace S. Field of dreams. How I put health status goals to work in Iowa. Interview by Kevin Lumsdon. HOSPITALS & HEALTH NETWORKS 1993; 67:10. [PMID: 8508222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Kan Z, Ivancev K, Lunderquist A, McCuskey PA, Wright KC, Wallace S, McCuskey RS. In vivo microscopy of hepatic tumors in animal models: a dynamic investigation of blood supply to hepatic metastases. Radiology 1993; 187:621-6. [PMID: 8497606 DOI: 10.1148/radiology.187.3.8497606] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The dynamics of blood circulation in three experimental animal models of hepatic metastasis were investigated with in vivo microscopy. It was demonstrated that the tumor vasculature communicated with the portal venules and hepatic sinusoids that surrounded the tumors. The hepatic artery was not seen to connect to the tumors directly. However, it was demonstrated that arterial blood entered tumors through the portal venules and that the hepatic arterial flow entered the tumor without resistance, while blood from the portal vein met great resistance at the tumor border, with only small amounts entering the tumor. Interruption of either the hepatic artery or the portal vein did not result in cessation of the blood circulation in hepatic tumors. A reciprocal relationship between the hepatic arterial and portal venous supplies to hepatic tumors was suggested, and it was hypothesized that arterioportal communications play an important role in the arterial and portal venous supply of blood to hepatic tumors. A comprehensive understanding of the blood supply of hepatic tumors is important for improving clinical treatment of hepatic tumors.
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Kohn CW, Sams R, Kowalski JJ, Powers J, Wallace S. Pharmacokinetics of single intravenous and single and multiple dose oral administration of rifampin in mares. J Vet Pharmacol Ther 1993; 16:119-31. [PMID: 8345562 DOI: 10.1111/j.1365-2885.1993.tb00156.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The disposition of rifampin in six healthy mares after single intravenous (i.v.) and oral (p.o.) doses and after seven oral doses of 10 mg/kg administered twice a day was investigated using a high performance liquid chromatographic (HPLC) method. Pharmacokinetic variables for rifampin determined using the HPLC method were comparable to variables reported from earlier studies utilizing a microbiological assay. Desascetylrifampin, a major metabolite of the parent compound, could not be detected in the serum but was detected at low concentrations in urine. Mean trough concentrations of rifampin increased from the first to the second dose of the multiple dose oral study and then remained unchanged through 72 h. At 84 h after the first dose (i.e. 12 h after the final dose) the rifampin concentration was significantly decreased (P = 0.001). The harmonic mean of the half-life of rifampin decreased significantly from 13.3 h after a single oral dose of 7.99 h after the seventh oral dose. The mean serum protein binding of rifampin over the concentration range of 2-20 micrograms/ml was 78%. Mean trough serum concentrations of unbound rifampin after multiple oral doses ranged from 0.67 micrograms/ml at 24 h to 0.40 micrograms/ml at 72 h. The mean unbound serum rifampin concentration at 84 h (i.e., 12 h after the final dose) was 0.30 micrograms/ml. Trough concentrations and the 84-h sample concentration of unbound rifampin exceeded the minimum inhibitory concentration for most gram positive bacterial isolates from horses reported in this study. All organisms with minimum inhibitory concentrations less than 0.125 micrograms/ml were considered susceptible. Based on the pharmacokinetics of rifampin after p.o. administration, we concur with the current dosage recommendation of 10 mg/kg twice a day by mouth. At this dose, most streptococci, Rhodococcus equi, and coagulase-positive staphylococci would be considered susceptible to rifampin.
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Richli WR, Roger DJ, Carrasco CH, Charnsangavej C, Rosenthal DI, Wallace S. An anatomical study of the tarsal tunnel using low pressure compartmental infusion. FOOT & ANKLE 1993; 14:257-60. [PMID: 8349210 DOI: 10.1177/107110079301400504] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The anatomy of the tarsal tunnel is demonstrated using a low-pressure compartmental infusion technique. This is done by infusing colored radiopaque contrast material into three fresh cadaveric specimens. Thin section photography and computed tomography are then used to identify the boundaries and contents of the tarsal tunnel as it traverses the ankle, hindfoot, and midfoot. The tarsal tunnel is shown to communicate proximally with the deep posterior compartment of the leg and distally with the intermediate compartment of the forefoot. The relationships of the structures contained within the tarsal tunnel are shown in detail.
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Abstract
Services for epilepsy in the UK are poor in quality, fragmentary and poorly organized. We attempt to define and quantify the scope, content and standards of medical, paramedical and nursing services required, from primary health care to specialist centres. This document has been approved by the Joint Epilepsy Council of Great Britain and Ireland, representing all major patient organizations and care providers.
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Evans J, Maccabee M, Hatahet Z, Courcelle J, Bockrath R, Ide H, Wallace S. Thymine ring saturation and fragmentation products: lesion bypass, misinsertion and implications for mutagenesis. Mutat Res 1993; 299:147-56. [PMID: 7683083 DOI: 10.1016/0165-1218(93)90092-r] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We have used thymine glycol and dihydrothymine as representative ring saturation products resulting from free-radical interaction with DNA pyrimidines, and urea glycosides and beta-ureidoisobutyric acid (UBA) as models for pyrimidine-ring fragmentation products. We have shown that thymine glycol and the ring-fragmentation products urea and beta-ureidoisobutyric acid, as well as abasic sites, are strong blocks to DNA polymerases in vitro. In contrast, dihydrothymine is not a block to any of the polymerases tested. For thymine glycol, termination sites were observed opposite the putative lesions, whereas for the ring-fragmentation products, the termination sites were primarily one base prior to the lesion. These and other data have suggested that thymine glycol codes for an A, and that a base is stably inserted opposite the damage, whereas when a base is inserted opposite the non-coding lesions, it is removed by the 3-->5 exonuclease activity of DNA polymerase I. Despite their efficiency as blocking lesions, thymine glycol, urea and UBA can be bypassed at low frequency in certain specific sequence contexts. When the model lesions were introduced individually into single-stranded biologically active DNA, we found that thymine glycol, urea, beta-ureidoisobutyric acid, and abasic sites were all lethal lesions having an activation efficiency of 1, whereas dihydrothymine was not. Thus the in vitro studies predicted the in vivo results. When the survival of biologically active single-stranded DNA was examined in UV-induced Escherichia coli cells where the block to replication was released, no increase in survival was observed for DNA containing urea or abasic sites, suggesting inefficient bypass of these lesions. In contrast, beta-ureidoisobutyric acid survival was slightly enhanced, and transfecting DNA containing thymine glycols was significantly reactivated. When mutation induction by unique lesions was measured using f1-K12 hybrid DNA containing an E. coli target gene, thymine glycols and dihydrothymine were found to be inefficient as premutagenic lesions, suggesting that in vivo, as in vitro, they primarily code for A. In contrast, urea and beta-ureidoisobutyric acid were efficient premutagenic lesions, with beta-ureidoisobutyric acid being about 4-5-fold more effective than urea glycosides, which have approximately the same rate of mutation induction as abasic sites from purines. Sequence analysis of the mutations resulting from these ring-fragmentation products shows that the mutations produced are both lesion and sequence context dependent. The possible roles that bypass efficiency and lesion-directed misinsertion might play in mutagenesis are discussed.
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Moulopoulos LA, Varma DG, Charnsangavej C, Wallace S. Magnetic resonance imaging and computed tomography appearance of asymptomatic paravaginal cysts. Clin Imaging 1993; 17:126-32. [PMID: 8348402 DOI: 10.1016/0899-7071(93)90052-o] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The magnetic resonance imaging (MRI) and computed tomography (CT) appearance of 18 paravaginal cysts was reviewed. On MRI, serious cysts were hypointense on T1-weighted and hyperintense on T2-weighted images. Cysts presumed to contain proteinaceous material were hyperintense on T1-weighted and T2-weighted sequences while hemorrhagic cysts exhibited varying stages of hemorrhage. On CT, a high attenuation cyst was presumed to contain proteinaceous material or hemorrhage. MRI and CT examination may reveal paravaginal cysts; their varied appearance must be recognized to avoid confusion with other lesions.
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Forstová J, Krauzewicz N, Wallace S, Street AJ, Dilworth SM, Beard S, Griffin BE. Cooperation of structural proteins during late events in the life cycle of polyomavirus. J Virol 1993; 67:1405-13. [PMID: 8382302 PMCID: PMC237510 DOI: 10.1128/jvi.67.3.1405-1413.1993] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The polyomavirus minor late capsid antigen, VP2, is myristylated on its N-terminal glycine, this modification being required for efficient infection of mouse cells. To study further the functions of this antigen, as well as those of the other minor late antigen, VP3, recombinant baculoviruses carrying genes for VP1, VP2, and VP3 have been constructed and the corresponding proteins have been synthesized in insect cells. A monoclonal antibody recognizing VP1, alpha-PyVP1-A, and two monoclonal antibodies against the common region of VP2 and VP3, alpha-PyVP2/3-A and alpha-PyVP2/3-B, have been generated. Reactions of antibodies with antigens were characterized by indirect immunofluorescence, immunoprecipitation, and immunoblot analysis. Immunofluorescent staining of mouse cells infected with polyomavirus showed all antigens to be localized in nuclei. When the late polyomavirus proteins were expressed separately in insect cells, however, only VP1 was efficiently transported into the nucleus; VP2 was localized discretely around the outside of the nucleus, and VP3 exhibited a diffused staining pattern in the cytoplasm. Coexpression of VP2, or VP3, with VP1 restored nuclear localization. Immunoprecipitation of infected mouse cells with either anti-VP1 or anti-VP2/3 antibodies precipitated complexes containing all three species, consistent with the notion that VP1 is necessary for efficient transport of VP2 and VP3 into the nucleus. Purified empty capsid-like particles, formed in nuclei of insect cells coinfected with all three baculoviruses, contained VP2 and VP3 proteins in amounts comparable to those found in empty capsids purified from mouse cells infected with wild-type polyomavirus. Two-dimensional gel analysis of VP1 species revealed that coexpression with VP2 affects posttranslational modification of VP1.
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Yang D, Kuang LR, Cherif A, Tansey W, Li C, Lin WJ, Liu CW, Kim EE, Wallace S. Synthesis of [18F]fluoroalanine and [18F]fluorotamoxifen for imaging breast tumors. J Drug Target 1993; 1:259-67. [PMID: 8069568 DOI: 10.3109/10611869308996084] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
To develop ligands for imaging breast tumors, [18F]fluoro analogue of tamoxifen and [18F]fluoroalanine were radiosynthesized. In vivo biodistribution studies were performed in mammary tumor-bearing rats. In studies on the biodistribution of an [18F]fluoro analogue of tamoxifen, tumor uptake decreased when rats were pretreated with diethylstilbestrol (DES), suggesting that tracer uptake in tumors was receptor-mediated. An estrogen receptor assay indicated that tumors have a receptor density of 7.5 fmol/mg protein. Studies of the distribution of [18F]fluoroalanine in tissue showed that the tumor-to-tissue ratio increases as a function of time. Positron emission tomography (PET) images of tumor-bearing rats demonstrated that tumors can be visualized 1 h after rats are injected with an [18F]fluoro analogue of tamoxifen. PET imaging of pigs after injection of 10 mCi of [18F]fluoro analogue of tamoxifen showed uterine uptake that could be blocked by DES (50 mg). The findings suggest that both radiotracers are useful for imaging breast tumors.
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Yamashita Y, Takahashi M, Baba Y, Kanazawa S, Charnsangavej C, Yang D, Wallace S. Hepatocellular carcinoma with or without cirrhosis: a comparison of CT and angiographic presentations in the United States and Japan. ABDOMINAL IMAGING 1993; 18:168-75. [PMID: 8382545 DOI: 10.1007/bf00198057] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We compared the computed tomographic (CT) and angiographic presentations of hepatocellular carcinoma (HCC) with or without cirrhosis in the United States and Japan. Tumors in the United States were advanced and less frequently associated with liver cirrhosis (association of cirrhosis: United States 56.2%, Japan 91.0%. In patients with cirrhosis, the size of the tumor tended to be smaller, and nodular tumors (single or multiple) were frequent. In early stage of HCCs with cirrhosis, tumors were hypovascular without a capsule. In advanced stage, tumors were hypervascular and a capsule was frequently observed around the tumor both with CT and angiography. HCCs without cirrhosis were seen in younger patients. These tumors were large at the time of diagnosis. A massive or diffuse mass without a capsule was frequently seen. Most tumors were hypodense on precontrast CT and hypervascular on angiography. Lymph node enlargement was significantly frequent. The radiological characteristics of HCC in both countries were significantly different depending upon associated cirrhosis, as well as the time of the diagnosis.
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272
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Yamashita Y, Takahashi M, Kanazawa S, Charnsangavej C, Wallace S. Parenchymal changes of the liver in cholangiocarcinoma: CT evaluation. GASTROINTESTINAL RADIOLOGY 1992; 17:161-6. [PMID: 1312967 DOI: 10.1007/bf01888536] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We evaluated parenchymal changes of the liver in 92 patients (41 peripheral types and 51 hilar types) with cholangiocarcinomas studied by bolus-enhanced computed tomography (CT). In 39% of patients with the peripheral type, a wedge-shaped increased enhancement of the liver was observed peripheral to the tumor on bolus-enhanced CT. Tumor was observed in all cases. In 58.8% of patients with the hilar type, a segmental or lobar increased degree of enhancement of the liver was observed, but the tumor was demonstrated in only 58.8%. Atrophy was accompanied by areas of increased enhancement in 80% of hilar type and 25% of peripheral type. Areas of increased degree of enhancement corresponded to a wedged-shaped perfusion defect on CT during arterial portography. On magnetic resonance imaging (MRI), those lesions showed hyperintensity on T2-weighted images. Most of these changes were considered to be due to reversible hepatic parenchymal ischemia secondary to portal vein invasion by the tumor.
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273
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Yang DJ, Cherif A, Tansey W, Kuang LR, Li C, Wright KC, Kim EE, Wallace S. N,N-Diethylfluoromethyltamoxifen: Synthesis, assignment of 1H and 13C spectra and receptor assay. Eur J Med Chem 1992. [DOI: 10.1016/0223-5234(92)90023-t] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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274
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Di Gregorio C, Rivasi F, Mongiardo N, De Rienzo B, Wallace S, Visvesvara GS. Acanthamoeba meningoencephalitis in a patient with acquired immunodeficiency syndrome. Arch Pathol Lab Med 1992; 116:1363-5. [PMID: 1456885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Several cases of Acanthamoeba encephalitis (ie, granulomatous amebic encephalitis) have been reported in patients with acquired immunodeficiency syndrome from the United States. To our knowledge, none so far has been reported from Europe, and this is the first case of amebic meningoencephalitis due to Acanthamoeba in a patient with acquired immunodeficiency syndrome from Italy. The patient was a 24-year-old, human immunodeficiency virus-positive heterosexual man with a 6-year history of intravenous drug use. He was admitted to the hospital because of severe headache, confusion, nuchal rigidity, jaundice, and ascites. He died 5 days later. At autopsy, the brain showed extensive hemorrhagic necrosis with numerous trophic and cyst forms of Acanthamoeba. The amebas were identified as Acanthamoeba divionensis by the indirect immunofluorescence test.
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275
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Chimelli L, Hahn MD, Scaravilli F, Wallace S, Visvesvara GS. Granulomatous amoebic encephalitis due to leptomyxid amoebae: report of the first Brazilian case. Trans R Soc Trop Med Hyg 1992; 86:635. [PMID: 1287925 DOI: 10.1016/0035-9203(92)90164-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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