Separation of 44Ti from proton irradiated scandium by using solid-phase extraction chromatography and design of 44Ti/44Sc generator system.

Scandium-44g (half-life 3.97h [1]) shows promise for positron emission tomography (PET) imaging of longer biological processes than that of the current gold standard, 18F, due to its favorable decay parameters. One source of 44gSc is the long-lived parent nuclide 44Ti (half-life 60.0 a). A 44Ti/44gSc generator would have the ability to provide radionuclidically pure 44gSc on a daily basis. The production of 44Ti via the 45Sc(p,2n) reaction requires high proton beam currents and long irradiation times. Recovery and purification of no-carrier added (nca) 44Ti from scandium metal targets involves complex separation chemistry. In this study, separation systems based on solid phase extraction chromatography were investigated, including branched diglycolamide (BDGA) resin and hydroxamate based ZR resin. Results indicate that ZR resin in HCl media represents an effective 44Ti/44gSc separation system.

Differential susceptibilities of the prosthetic heme of hemoglobin-based red cell substitutes. Implications in the design of safer agents.

One approach to the development of an effective red cell substitute has been chemical modification of human hemoglobin to optimize oxygen transport and plasma half-life. Human hemoglobin A0 and two of these modified hemoglobins, one prepared from the cross-linking of the alpha-chains at lysine residue 99 by bis(3,5-dibromosalicyl)fumarate (Hb-DBBF) and the other by acylation of lysine residue 82 of the beta-chain by mono-(3,5-dibromosalicyl)fumarate (Hb-FMDA), were tested by HPLC for their susceptibility to oxidative damage caused by H2O2. Such oxidative insult may occur during ischemia and reperfusion of tissues after transfusion of red cell substitutes to patients with hypovolemic shock and trauma. Hb-DBBF was extremely susceptible to damage of its heme and protein moieties with stoichiometric amounts of H2O2, whereas Hb-FMDA was highly resistant, even at 10-fold molar excess and at an acidic pH of 4.7. Hemoglobin A0 was of intermediate susceptibility, exhibiting alteration of heme and protein moieties at acidic but not neutral pH. Since the degradation of heme can release the potentially toxic agent iron, Hb-FMDA may be a more promising candidate than Hb-DBBF for development as a red cell substitute. A similar approach may be used to assess the susceptibility of other hemoglobin-based red cell substitutes to oxidative damage in order to determine the molecular basis of heme and protein alteration.

Regulation of the embryonic cell proliferation by Drosophila cyclin D and cyclin E complexes.

Cell proliferation during Drosophila development occurs in a well known spatial and temporal pattern which can readily be studied in vivo. The cells which form the larval epidermis exit from the cell division cycle during embryogenesis after the 16th round of mitosis when they enter for the first time into a G1/0 phase. We are interested in the mechanistic basis of this cell proliferation arrest. We have shown that the arrest requires the down-regulation of cyclin E/Cdk2 activity by inhibition of cyclin E expression and parallel activation of Dacapo/p27 expression. In addition, up-regulation of Fizzy-related is observed and is required for inhibition of Cdk1 activity. Do these processes result from the down-regulation of D-type cyclin/Cdk complexes? Extensive evidence from mammalian cells, and in particular from tumour cells has suggested that these complexes act as master regulators of cell proliferation upstream of cyclin E. Our genetic analyses indicate that Drosophila cyclin D/Cdk4, which interacts with the Drosophila Rb family member as expected, does not play an essential role in the regulation of cell proliferation.

Intrathoracic splenosis: superiority of technetium Tc 99m heat-damaged RBC imaging.

Intrathoracic splenosis is a rare diagnosis that is usually made following an invasive procedure. Although radiographic and CT findings are nonspecific, these findings combined with a history of splenic injury should suggest the possibility of this diagnosis. We present a patient with intrathoracic splenosis diagnosed on the basis of a technetium Tc 99m heat-damaged RBC scan following false-negative technetium Tc 99m sulfur colloid scan results.

Sulfasalazine pulmonary toxicity in ulcerative colitis mimicking clinical features of Wegener's granulomatosis.

The centrally accentuated antineutrophil cytoplasmic antibody test (c-ANCA) is widely regarded as a sensitive and specific marker for Wegener's granulomatosis (WG). There are increasing reports, however, of false-positive c-ANCAs, usually in the setting of other vasculidities. We report a case of a 27-year-old man with ulcerative colitis who developed pulmonary symptoms, peripheral nodular lung infiltrates, and an elevated c-ANCA suggesting WG. Chest CT and open lung biopsy specimens were consistent with WG. The symptoms and pulmonary infiltrates resolved after discontinuation of sulfasalazine therapy. The c-ANCA remained elevated due to the occurrence of false-positive values in ulcerative colitis. We conclude sulfasalazine toxicity can mimic clinical aspects of WG and that c-ANCA testing should be interpreted with caution in patients with ulcerative colitis.

Inflammatory diseases of the lung causing false-positive 131iodine whole body scans in the evaluation of papillary thyroid carcinoma. Two case reports.

The 131I whole body scan is commonly used to establish the presence of metastatic disease in papillary thyroid carcinoma. False-positive scans are rare, but have been reported. We present two cases of aberrant uptake of radioiodine after thyroidectomy and 131I ablation due to inflammatory conditions of the lung, aspergilloma, and respiratory bronchiolitis.

CT fluoroscopy for thoracic interventional procedures.

In the past several years, CT fluoroscopy has proved a valuable new technique in guiding the performance of intrathoracic procedures. Several approaches to using CT fluoroscopy are discussed. We have found an interrupted, real-time technique optimal to facilitate biopsy of percutaneous lung nodules, particularly small lesions. The technique is also valuable in assisting thoracic drainage procedures. This article also discusses the use of CT fluoroscopy to guide transbronchial needle aspiration, which is another potentially important application.

Missed lung cancer on chest radiography and computed tomography: imaging and medicolegal issues.

Missed lung cancer is an important medicolegal issue and is the second leading cause for malpractice actions against radiologists. Contributing factors to overlooked lung cancer can be ascribed to observer performance, lesion characteristics, and technical considerations. Of these, errors related to observer performance are probably the most important. Missed lung cancer does not necessarily constitute malpractice, but lesions of high conspicuity are more likely to be associated with an adverse legal outcome. Multiple strategies have been advocated to reduce the frequency of missed lung cancer. Several studies have emphasized the importance of careful comparison of the current radiograph with one or more prior examinations.

After the trial: abusing the expert--a Canadian case report.

A public outcry often follows murder trials in which the defence of insanity is successfully pleaded. Possible explanations for this concern, and the Canadian media's role in promoting it, are discussed.

Is there sex after the prison door slams shut?

Despite the growing frequency of treatment-resistant STDs, North American literature and practice continue to stress repression and to evidence denial of prison sexuality. The authors outline their observations concerning prison sex, including officer-inmate sex. (Since this article was submitted, officer-inmate sex has received widespread public attention in Georgia, USA.)

Differential progressive remodeling of coronary and cerebral arteries and arterioles in an aortic coarctation model of hypertension.

OBJECTIVES: Effects of hypertension on arteries and arterioles often manifest first as a thickened wall, with associated changes in passive material properties (e.g., stiffness) or function (e.g., cellular phenotype, synthesis and removal rates, and vasomotor responsiveness). Less is known, however, regarding the relative evolution of such changes in vessels from different vascular beds. METHODS: We used an aortic coarctation model of hypertension in the mini-pig to elucidate spatiotemporal changes in geometry and wall composition (including layer-specific thicknesses as well as presence of collagen, elastin, smooth muscle, endothelial, macrophage, and hematopoietic cells) in three different arterial beds, specifically aortic, cerebral, and coronary, and vasodilator function in two different arteriolar beds, the cerebral and coronary. RESULTS: Marked geometric and structural changes occurred in the thoracic aorta and left anterior descending coronary artery within 2 weeks of the establishment of hypertension and continued to increase over the 8-week study period. In contrast, no significant changes were observed in the middle cerebral arteries from the same animals. Consistent with these differential findings at the arterial level, we also found a diminished nitric oxide-mediated dilation to adenosine at 8 weeks of hypertension in coronary arterioles, but not cerebral arterioles. CONCLUSION: These findings, coupled with the observation that temporal changes in wall constituents and the presence of macrophages differed significantly between the thoracic aorta and coronary arteries, confirm a strong differential progressive remodeling within different vascular beds. Taken together, these results suggest a spatiotemporal progression of vascular remodeling, beginning first in large elastic arteries and delayed in distal vessels.

Environmental NGOs in Ecuador: an economic analysis of institutional change.

PIP: Nongovernmental organizations (NGOs) in Latin America have grown more rapidly than has our understanding of the economic and political implications of this major institutional change. In Ecuador, between 1984 and late 1992, at least 24 new environmental NGOs emerged. An economist does a case study of them, especially Fundacion Natura (FN) in Ecuador, to understand their role and behavior which are a large part of environmental politics in Latin America. NGOs are successful because the public sector cannot meet the countries' needs and donors want to help NGOs, thereby providing the demand. For example, FN has received funding from USAID, World Wildlife Fund, the International Union for the Conservation of Nature, and other groups. FN charges donors 15% to cover administrative costs while many other NGOs do not receive international funding for administrative costs. FN is well connected with the public sector which is supportive and beneficial. FN activities complement the public sector's efforts in the environment. Further, it is well connected with private industry from whom it receives financial support. It has been criticized for supporting industry on some environmental issues, however. In fact, its Cuenca chapter split from FN in 1984 to form Tierra Viva, because FN sided with industry when industry wanted to build on agricultural land in Cuenca. FN's relationship with USAID is strained. FN is successful because it employs quality personnel who are committed to FN objectives. Yet FN and other NGOs do not have the monetary incentives for efficient production. Most other NGOs are financially strapped and depend on volunteers. The more radical environmental NGOs do not accept donations from the private sector and do not want to work with government. Despite the influence donors have on NGOs, the NGOs' powerful presence and their environmental education programs have consequences beyond donor control (e.g., FN and USAID).^ieng

Coronary artery calcification at CT as a predictor for cardiac complications of thoracic surgery.

PURPOSE: Our goal was to determine the predictive value of coronary artery calcification (CAC) on preoperative CT of the thorax for cardiac complications of noncardiac thoracic surgery. METHOD: Of 117 patients undergoing noncardiac thoracic surgical procedures between January 1, 1993, and June 1, 1995, at our institution, 75 had inpatient records and chest CTs available for retrospective review. Inpatient records were reviewed for postoperative cardiac complications (arrhythmia, hypotension with ECG changes, myocardial infarction, congestive heart failure, stroke, and death). The CT scans were scored for the presence and extent of CAC by an independent observer. RESULTS: Six of the 75 patients had cardiac complications including 1 death. Thirty-nine of the 75 patients had a CAC score of > or = 7. The sensitivity, specificity, positive predictive value, and negative predictive value of a CAC score of > or = 7 for cardiac complications were 100, 71, 23, and 100%, respectively. CONCLUSION: The presence of CAC on preoperative CT scanning is associated with cardiac complications of noncardiac thoracic surgery; however, the positive predictive value is low. The absence of CAC was a reliable predictor of a favorable postoperative cardiac course.

Cartilaginous disorders of the chest.

Cartilaginous disorders of the thorax can arise in the parenchyma, airways, chest wall, and axial skeleton. At radiography, pulmonary hamartoma is characterized by "popcorn" calcification or fat density, either of which is diagnostic. Bronchiectasis is best demonstrated at high-resolution computed tomography (CT) and has a "tramline" or "signet ring" appearance. Tracheopathia osteochondroplastica appears at CT as multiple sessile submucosal nodules with or without calcification along the cartilaginous portion of the trachea. In relapsing polychondritis, the trachea and mainstem bronchi have diffuse or focal thickening with luminal narrowing at radiography. Costochondritis of the chest wall has become more prevalent with increased intravenous drug abuse and may be demonstrated at CT as soft-tissue swelling along with underlying cartilaginous fragmentation and bone destruction. Enchondromas are expansile and may display a calcified cartilaginous matrix at radiography. In osteochondroma, the thickness of the cartilaginous cap determines the likelihood of malignant degeneration. At radiography, chondroblastomas have a round contour, sharp margins, and cortical scalloping, whereas chondrosarcomas are large masses with indistinct margins, cortical breakthrough, and soft-tissue extension. By identifying either a process affecting a cartilage-containing structure or a cartilaginous matrix within a lesion, the chest radiologist may be able to narrow the list of differential diagnostic possibilities substantially.