[Analgesic action of intracerebral injection of adrenaline in relation to that of morphine].
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Animals↗
Biomedical subjects
S Chang
Publications and source records attributed to S Chang.
Volume MRI and MRSI techniques for the quantitation of treatment response in brain tumors: presentation of a detailed case study.
Patients with primary brain tumors may be considered for several different treatments during the course of their disease. Assessments of disease progression and response to therapy are typically performed by visual interpretation of serial MRI examinations. Although such examinations provide useful morphologic information, they are unable to reliably distinguish active tumor from radiation necrosis. This poses a particular problem in the assessment of response to localized radiation therapies such as gamma knife radiosurgery. In this paper, we present methodology for evaluating changes in tissue morphology and metabolism based on serial volumetric MRI and magnetic resonance spectroscopic imaging (MRSI) examinations. Registration and quantitative analysis of these data provide measurements of the temporal and spatial distributions of gadolinium enhancement and of N-acetylasparate, choline, creatine, and lactate/lipid. The key features of this approach and the potential clinical benefits are illustrated by a detailed analysis of six serial MRI/MRSI examinations and three serial 1-[F-18] fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) studies on a patient with a recurrent anaplastic astrocytoma.
Adult↗
Photochemical synthesis of simple organic free radicals on simulated planteary surfaces-an ESR study.
Electron spin resonance spectroscopy provided evidence for formation of hydroxyl radicals during ultraviolet photolysis (254 nm) at -170C of H2O adsorbed on silica gel or of silica gel alone. The carboxyl radical was observed when CO or CO2 or a mixture of CO and CO2 absorbed on silica gel at -170C was irradiated. The ESR signals of these radicals slowly disappeared when the irradiated samples were warmed to room temperature. However, re-irradiation of CO or CO2, or the mixture CO and CO2 on silica gel at room temperature then produced a new species, the carbon dioxide anion radical, which slowly decayed and which was identical with that produced by direct photolysis of formic acid adsorbed on silica gel. The primary photochemical process may involve formation of hydrogen and hydroxyl radicals by means of (1) photodissociation of H2O physically adsorbed on the silica gel, or (2) absorption of the excitation energy by the silica gel surface with subsequent cleavage of the silanol bonds, or (3) dissociation of H2O molecules throug photosensitization by the surfaces or a combination of (1) to (3). Subsequent reactions of these radicals with adsorbed CO or CO2 or both yield carboxyl radicals, CO2H, the precsursors of formic acid. Our results confirm the formation of formic acid under simulated Martian conditions and provide a mechanistic basis for gauging the potential importance of gas-solid photochemistry for chemical evolution on other extraterrestrial bodies, on the primitive earth and on dust grains in the interstellar medium.
Adsorption↗
Asymmetric structure of five and six membered DNA hairpin loops.
The tertiary structure of nucleic acid hairpins was elucidated by means of the accessibility of the single-strand-specific nuclease from mung bean. This molecular probe has proven especially useful in determining details of the structural arrangement of the nucleotides within a loop. In this study 3'-labeling is introduced to complement previously used 5'-labeling in order to assess and to exclude possible artifacts of the method. Both labeling procedures result in mutually consistent cleavage patterns. Therefore, methodological artifacts can be excluded and the potential of the nuclease as structural probe is increased. DNA hairpins with five and six membered loops reveal an asymmetric loop structure with a sharp bend of the phosphate-ribose backbone between the second and third nucleotide on the 3'-side of a loop. These hairpin structures differ from smaller loops with 3 or 4 members, which reveal this type of bend between the first and second 3' nucleotide, and resemble with respect to the asymmetry anticodon loops of tRNA.
Base Sequence↗
Quantum chemical study of the thermodynamics, kinetics of formation and bonding of H2CN: relevance to prebiotic chemistry.
Using the Iterative Extended Huckel Theory (IEHT), energy-conformation studies have been carried out for H2CN (I), trans-HCNH (IIA), and cis-HCNH (IIB), three possible isomers formed by addition of a hydrogen atom to hydrogen cyanide. Calculations show that the order of decreasing thermodynamic stability is I greater than IIA greater than IIB. Additionally, from calculated energies along simulated reaction pathways, the formation of I from HCN+H appears to be kinetically favored over IIA. Calculated properties of the minimum energy conformers of I and IIA are described and the potential role of H2CN (I) as a reactive intermediate in prebiotic organic synthesis and its possible relevance to interstellar organic chemistry are discussed.
Atmosphere↗
Social stimulation of the severely malnourished child: a home training programme.
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Child, Preschool↗
Arteriovenous malformation of the pancreas in a patient with gastrointestinal bleeding: helical CT findings.
Dynamic computed tomographic (CT) findings of arteriovenous malformation (AVM) of the pancreas include strong enhancement or conglomeration of small hypervascular spots in the pancreas and early contrast filling of the portal vein during the arterial phase. We describe a case with pancreatic AVM in which we identified enlarged arterial feeders and draining veins as supportive findings of the diagnosis and ulceration into the pancreatic duct as a possible cause of gastrointestinal bleeding at contrast-enhanced CT.
Arteriovenous Malformations↗
Prediction of rejection in lung transplantation.
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Acute Disease↗
Genomic analysis of renal allograft dysfunction using cDNA microarrays.
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Graft Rejection↗
Carbon isotope composition of low molecular weight hydrocarbons and monocarboxylic acids from Murchison meteorite.
The origin of the organic matter in carbonaceous meteorites remains controversial despite extensive study over the past 20 yr. Motivated by the expectation that the patterns of isotopic variation with molecular structure among the organic compounds would contain important clues to their origin, we have measured the carbon isotopic compositions for individual hydrocarbons and monocarboxylic acids from Murchison meteorite, a C2 carbonaceous chondrite which fell in Australia in 1969. With few exceptions, notably benzene, the volatile products are substantially isotopically heavier than their terrestrial counterparts, signifying their extraterrestrial origin. For both classes of compounds, the ratio of 13C to 12C decreases with increasing carbon number in a roughly parallel manner, and each carboxylic acid exhibits a higher isotopic ratio than the hydrocarbon containing the same number of carbon atoms. These trends are consistent with the kinetically controlled synthesis of higher homologues from lower ones. The results suggest the possibility that the production mechanisms for hydrocarbons and carboxylic acids may be similar; they also impose constraints on the identity of the reactant species.
Carbon Dioxide↗
Temporal expression of urokinase plasminogen activator, plasminogen activator inhibitor and gelatinase-B in chronic wound fluid switches from a chronic to acute wound profile with progression to healing.
The plasminogen activator/plasmin system is known to initiate a proteolytic cascade resulting in the activation of matrix metalloproteinases in vitro leading to the degradation of extracellular matrix. To investigate whether or not this cascade is present during delayed wound healing and contributes to the pathophysiological basis of impaired healing we examined the temporal expression of urokinase plasminogen activator, plasminogen activator inhibitor-1 and gelatinase-B in fluid collected from chronic venous leg ulcers compared to acute surgical mastectomy wounds. Using a chromogenic substrate assay, levels of active urokinase plasminogen activator in chronic wounds were found to be about five fold higher compared to sera and two fold higher compared to mastectomy wounds. Levels of active plasminogen activator inhibitor-1 in chronic wounds were four times higher than those found in sera and two times higher than those found in mastectomy wound fluid. Using a fibrin overlay system and reverse zymography, we found that when the wound was not healing, the expression of urokinase plasminogen activator in chronic wound fluid was initially detected in the active forms (50 and 33 kDa), but that as the wound healed and decreased in size, was detected as an inhibitor- bound urokinase plasminogen activator-plasminogen activator inhibitor-1 complex ( congruent with 80-116 kDa). When the expression of active urokinase plasminogen activator was highest, no plasminogen activator inhibitor-1 was detectable. In contrast, urokinase plasminogen activator was always detected in the inhibitor bound form as a urokinase plasminogen activator-plasminogen activator inhibitor-1 complex in blood- and plasma-derived serum and mastectomy wound fluid. Plasminogen activator inhibitor-1 was detected in blood-derived serum and mastectomy wound fluid but not in plasma derived serum. Expression of matrix metalloproteinase-9 in chronic wound fluids, analyzed by gelatin zymography, showed that when urokinase plasminogen activator was detected in the active forms, matrix metalloproteinase-9 was overexpressed by approximately twice that found in mastectomy wounds and approximately 30 times that detected in blood-derived sera. When urokinase plasminogen activator appeared almost entirely as an enzyme- inhibitor complex, the level of expression of matrix metalloproteinase-9 was similar to that seen in mastectomy wound fluid. We conclude that the switch in urokinase plasminogen activator expression from an active to inhibitor bound form correlates with the decrease seen in matrix metalloproteinase-9 expression suggesting the presence of a proteolytic cascade initiated by the plasminogen activator/plasmin system during wound healing leading to the activation of matrix metalloproteinase-9. In addition, expression of urokinase plasminogen activator and matrix metalloproteinase-9 appear to be useful biomarkers to determine clinical wound healing status.
Adult↗
Home-screen: a short scale to measure fall risk in the home.
Community nurses are often the health professionals with whom older Australians living at home have most contact. The home environment has been identified to have a number of hazards associated with falls in older people. The Home-screen scale was specifically designed as a nurse-administered instrument to identify environmental and behavioral risks that alert nurses to the need for action to reduce fall risks in the home. A 14-item scale was administered to 1,165 older people receiving community nursing services. Psychometric investigation confirmed a 10-item scale with construct validity and internal consistency (alpha = 0.86, n = 989), explaining 60% of the construct of home safety (safe home environment and safe home behaviors). In addition, differences in mean scores were found in clients able and unable to transfer independently (t = 4.5 [df = 323.1] p < 0.001 [Group 1: M = 82.14, SD = 15.56; Group 2: M = 75.54, SD = 20.83, n = 989]). Similarly, an association existed between clients with low scores on the Home-screen scale and the perceived need for home modification. A score of 74 on this scale has been identified as a critical point for potential client injury. The use of this scale, both as an initial screening instrument and as a monitoring tool for community nurses working with older people, is recommended.
Accidents, Home↗
Local versus regional procurement and distribution of granulocytes.
Granulocyte concentrates obtained by discontinuous flow centrifugation (DFC) and continuous flow centrifugation (CFC) were studied. The DFC granulocytes were obtained from a regional center and stored for 24 hours prior to transfusion. The CFC granulocytes were obtained locally and transfused within a few hours. Even at 24 hours, DFC granulocytes had significantly reduced bactericidal capacity, chemiluminescence, nitroblue tetrazolium reduction, chemotaxis and random mobility. Granulocyte kinetics utilizing DF32P and skin windows demonstrated the ability of DFC granulocytes to circulate and migrate into the tissues despite the in vitro abnormalities. Until effective storage techniques for granulocyte preservation became available, rapid transportation and processing from regional centers or local procurement of granulocytes is necessary to transfuse functional granulocytes.
Blood Bactericidal Activity↗
Alignment of volume MR images and high resolution [18F]fluorodeoxyglucose PET images for the evaluation of patients with brain tumors.
PURPOSE: The goal of the study was to investigate the use of automated registration techniques for interpretation of volume MR and high resolution FDG-PET images that were obtained from patients with brain tumors. METHOD: Twenty-one patients with brain tumors were studied on one or more occasions using MRI and high resolution FDG-PET. The data were aligned using automated volume- and surface-matching algorithms. Composite images comprising the resliced pre- and postgadolinium spoiled GRE, T2-weighted SE, and PET data were constructed to correlate intensities of regions on the PET images with regions that corresponded to normal gray matter, white matter, and gadolinium enhancement. RESULTS: The accuracy of registration between the MR and PET images was estimated to be within 1-2 mm based upon the distance between surfaces of the outside of the head. In 12 of the 24 examinations, there were diagnoses of recurrent tumor, with only 5 of these exhibiting regions of higher FDG uptake than normal gray matter. For 19 of the 24 studies, the anatomic context provided by the registered MR images was found to be important in distinguishing recurrent tumor from necrosis based upon FDG uptake. CONCLUSION: The automated alignment was found to be an important factor in interpreting the high resolution PET images. This was particularly true for small lesions close to the cortex and for situations where FDG uptake had been reduced by prior treatment with radiation therapy.
Adult↗
A pilot study for a screening trial of cervical fluorescence spectroscopy.
Fluorescence spectroscopy is a promising technology for detection of epithelial precancers and cancers. In preparation for a multicenter phase II screening trial, a pilot trial was conducted to test data collection and patient examination procedures, use data forms, time procedures, and identify problems with preliminary data analysis. Women 18 years of age and older underwent a questionnaire, a complete history, and a physical examination, including a pan-colposcopy of the lower genital tract. A fiber-optic probe measured fluorescence excitation-emission matrices at 1-3 cervical sites for 58 women. The data collection procedures, data forms, and procedure times worked well, although collection times for all the clinical data take an average of 28 min. The clinical team followed procedures well, and the data could be retrieved from the database at all sites. The multivariate analysis algorithm correctly identified squamous normal tissue 99% of the time and columnar normal tissue only 7%. The assessment of ploidy from monolayer samples was not accurate in this small sample. The study was successful as a pilot trial. We learned who participated, who withdrew, how often abnormalities were present, and that algorithms that have worked extremely well in previous studies do not work as well when a few study parameters are changed. The current algorithm for diagnosis identified squamous normal tissue very accurately and did less well for columnar normal tissue. Inflammation may be an explanation for this phenomenon. Fluorescence spectroscopy is a promising technology for the detection of epithelial precancers and cancers. The screening trial of fluorescence and reflectance spectroscopy was successful.
Adult↗
Whole-abdominal radiation in endometrial carcinoma: an analysis of toxicity, patterns of recurrence, and survival.
PURPOSE: The purpose of this study was to determine the toxicity, patterns of recurrence, and survival in high-risk endometrial cancer patients treated with whole-abdominal radiation. MATERIALS AND METHODS: All patients with endometrial cancer treated at Northwestern University since 1994 and at Rush University since 1993 were retrospectively reviewed. Patients believed to be at high risk for intra-abdominal recurrence and who received whole-abdominal radiation were reviewed for this study. RESULTS: A total of 30 patients completed whole-abdominal radiation (WAR) and were available for study. The mean and median follow-up was 2.3 and 2.1 years, respectively, with a range of 0.13 to 6.1 years. Seventy-eight percent of the cohort received surgical staging with bilateral salpingo-oophorectomy/total abdominal hysterectomy/lymph node sampling. Forty-seven percent of the patients were found to have serous histology as a component of their tumor. Surgical staging results included 19% stage 1B, 4% stage IC, 8% stage IIB, 37% stage IIIA, 26% stage IIIC, and 7% stage IVB. Two patients had gross residual disease at the completion of surgery. Megestrol acetate (Megace) was used as an adjuvant treatment in 37% of patients, and no cases received initial chemotherapy. All patients received WAR with a mean total dose and dose per fraction of 2620 and 143 cGy, respectively. Twenty-two percent of patients received a para-aortic boost. The mean total pelvic dose was 4956 cGy. Seventy percent of patients received a vaginal cuff boost. Eight percent of patients had grade 3 acute gastrointestinal morbidity, and 4% had grade 4 acute gastrointestinal morbidity. No other grade 3 or greater acute or long-term morbidity was noted. At last follow-up, seven (23%) patients had experienced recurrence. The pattern of first recurrence was 0% in the vaginal cuff, 3% other vaginal, 7% pelvic, 7% upper abdominal, 3% lung, 7% bone, and 7% para-aortic lymph nodes. Ultimate recurrences were similar. At last follow-up, 77% patients had no evidence of disease, 13% were alive with disease, and 10% had died of disease. CONCLUSIONS: Utilizing a conservatrive total whole-abdominal radiation dose and limited para-aortic nodal boost resulted in very tolerable treatments. The patterns of recurrence and survival in this early report are encouraging.
Abdominal Neoplasms↗
Radiosurgery for brain metastases from primary lung carcinoma.
PURPOSE: Brain metastases are a common problem in patients with lung cancer. This retrospective review was performed to describe the efficacy and toxicity of stereotactic radiosurgery for brain metastases from lung carcinoma and to evaluate prognostic factors for survival. PATIENTS AND METHODS: A retrospective review was performed of 113 patients with the diagnosis of lung carcinoma who underwent radiosurgery with or without whole-brain radiotherapy for management of newly diagnosed or recurrent, single, or multiple brain metastases from 1991 through 1998 at the University of California, San Francisco. Freedom from progression and survival were measured from the date of radiosurgery and estimated using the Kaplan-Meier method. Prognostic factors were evaluated with the log-rank test and Cox proportional hazards models. RESULTS: The median patient age at the time of radiosurgery was 59 years (range, 37-82 years), and the median Karnofsky performance score was 90 (range, 50-100). The median survival time from radiosurgery was 12.0 months overall, 13.9 months for 41 patients treated with radiosurgery alone initially, 14.5 months for 19 patients treated with radiosurgery and whole-brain radiotherapy initially, and 10.0 months for 53 patients with recurrent brain metastases. Among newly diagnosed patients, multivariate analysis showed that improved survival was associated with absence of extracranial metastases and fewer brain metastases. Among patients with recurrent brain metastases, improved survival was associated with higher Karnofsky performance score, control of the primary tumor, and fewer metastases. Measured by lesion, 1-year local freedom from progression probabilities were 81% for radiosurgery alone, 86% for radiosurgery and whole-brain radiotherapy, and 65% for radiosurgery performed after recurrence. In patients with newly diagnosed brain metastases, there was a significantly greater risk of developing subsequent brain metastases and of worse overall brain freedom from progression after radiosurgery alone versus radiosurgery and whole-brain radiotherapy. One-year brain freedom from progression probabilities were 13% without salvage therapy and 62% with salvage therapy in the 41 patients treated initially with radiosurgery alone, versus 67% without salvage therapy and 89% with salvage therapy in the 19 patients treated initially with radiosurgery plus whole-brain radiotherapy. DISCUSSION: Radiosurgery is an effective therapy for selected patients with newly diagnosed or recurrent brain metastases from lung carcinoma. Initial whole-brain radiotherapy with radiosurgery appears to improve brain control but not survival. Prospective, randomized trials are needed to further investigate the role of radiosurgery with and without whole-brain radiotherapy for brain metastases.
Adenocarcinoma↗
Adjuvant methods in macular hole surgery: intraoperative plasma-thrombin mixture and postoperative fluid-gas exchange.
BACKGROUND AND OBJECTIVE: The optimal method for surgical management of idiopathic macular holes remains unknown. Adjuvant methods including intraoperative cytokines and postoperative fluid-gas exchange with and without laser have been described. We report on the safety and final results of routine intraoperative autologous plasma-thrombin mixture and postoperative fluid-gas exchange when necessary as an adjunct to the surgical therapy of this disease. PATIENTS AND METHODS: A consecutive series of 114 patients (mean age 66.9 years) with primary idiopathic full thickness Stage II, III, and IV macular holes were primarily treated by vitrectomy, fluid/perfluorocarbon gas exchange, and application of autologous plasma-thrombin mixture to the macular hole. Visible epiretinal membranes were peeled but the normal appearing internal limiting membrane was not routinely stripped. Outcome measures included final Snellen visual acuity, rate of macular hole closure, complications, and number of supplemental procedures performed. RESULTS: Closed at one month, were 110 of 121 (91%) macular holes, including two that underwent repeat fluid/gas exchange and laser within the first two weeks after surgery. At the time of final follow-up (mean: 10.9 months), 110 of 121 (91%) macular holes were closed. This included 8 of 9 eyes that had reopening of the macular hole between one and 21 months successfully treated by repeat fluid-gas exchange and 2 eyes that underwent a second successful pars plana vitrectomy, membrane peeling, and repeat fluid-gas exchange. Overall, 98 of 121 eyes overall (81%) were successfully treated by a single surgery; 94 of 121 (78%) achieved two lines or greater of visual improvement; 83 of 121 (69%) achieved 20/70 or better vision; and 47 eyes (39%) achieved 20/40 or better vision. Complications in this series included infectious endophthalmitis (1 eye), intraoperative retinal break (2 eyes), late retinal detachment (5 eyes), transient mild intraocular pressure elevation (46 eyes), inflammatory response (six eyes), epiretinal membrane (6 eyes), intraretinal hemorrhages (1 eye), and cataract (33 of 99 phakic eyes underwent cataract extraction during the follow-up). CONCLUSION: A combination of intravitreal perfluorocarbon gas and autologous plasma-thrombin mixture (tissue glue) was well tolerated in most patients and did not result in any specific long-term complications. The use of supplemental fluid-gas exchange when necessary improved the final success rate. Further well-controlled and randomized studies will be required to determine the efficacy of this as an adjunct or alternative to other methods of treatment for macular holes.
Adult↗