Democratic decay of 6Be exposed by correlations.

The interaction of an E/A=70-MeV (7)Be beam with a Be target was used to populate levels in (6)Be following neutron knockout reactions. The three-body decay of the ground and first excited states into the α+p+p exit channel were detected in the High Resolution Array. Precise three-body correlations extracted from the experimental data allowed us to obtain insight into the mechanism of the three-body democratic decay. The correlation data are in good agreement with a three-cluster-model calculation and thus validate this theoretical approach over a broad energy range.

Correlations in intermediate energy two-proton removal reactions.

We report final-state-exclusive measurements of the light charged fragments in coincidence with (26)Ne residual nuclei following the direct two-proton removal from a neutron-rich (28)Mg secondary beam. A Dalitz-plot analysis and comparisons with simulations show that a majority of the triple-coincidence events with two protons display phase-space correlations consistent with the (two-body) kinematics of a spatially correlated pair-removal mechanism. The fraction of such correlated events, 56(12)%, is consistent with the fraction of the calculated cross section, 64%, arising from spin S=0 two-proton configurations in the entrance-channel (shell-model) (28)Mg ground state wave function. This result promises access to an additional and more specific probe of the spin and spatial correlations of valence nucleon pairs in exotic nuclei produced as fast secondary beams.

Impact of sample volume and handling time during analysis on the in vitro quality measurements of platelet concentrates held in syringes.

INTRODUCTION: The determination of quality parameters is a necessity for monitoring the efficacy of platelet concentrates. During consolidated quality control studies, there may be a large number of samples to be analyzed at the same time. This common workflow setup triggered the question whether there is an influence of the number of samples to be analyzed on the accuracy of the test results. METHODS: Two different sample volumes of platelet concentrates, 1 ml and 50 ml, were analyzed for a set of standard in vitro parameters including pCO(2), pO(2), pH, glucose, and lactate as well as platelet activation via CD62P expression and responsiveness to adinosine diphosphate in an extent-of-shape-change assay. To assess apoptotic mechanisms triggered by the hold time, changes in the phosphatidylserine exposure were monitored. RESULTS: In total, eleven time points were assessed over a 3-h period as well as an overnight point for assay evaluation. Except for pCO(2) and pO(2), all in vitro parameters analyzed were unaffected by a sample hold time of up to 3-h. CONCLUSION: Sampling for pO(2) determination should be carried out in small volumes and assessed within 30 min of collection to obtain reliable and comparable results.

Neutron-proton asymmetry dependence of spectroscopic factors in ar isotopes.

Spectroscopic factors have been extracted for proton-rich 34Ar and neutron-rich 46Ar using the (p, d) neutron transfer reaction. The experimental results show little reduction of the ground state neutron spectroscopic factor of the proton-rich nucleus 34Ar compared to that of 46Ar. The results suggest that correlations, which generally reduce such spectroscopic factors, do not depend strongly on the neutron-proton asymmetry of the nucleus in this isotopic region as was reported in knockout reactions. The present results are consistent with results from systematic studies of transfer reactions but inconsistent with the trends observed in knockout reaction measurements.

IGF-1 bioavailability is increased by resistance training in older women with low bone mineral density.

We investigated if long-term resistance training would increase insulin-like growth factor-1 (IGF-1) bioavailabilty at rest in older women (68+/-1 years) with low bone mineral density. IGF-1 levels were significantly lower (P<0.05), and insulin-like growth factor binding proteins -1 and -3 (IGFBP-1 and IGFBP-3) significantly higher than an age-matched healthy normal group. Resistance training resulted in significant (P<0.05) increases in repetition maximums across all exercises (range 41-78%). Resting IGF-1 levels were significantly (P<0.05) elevated (70%) by the resistance training whereas no significant changes occurred in IGFBP-1 and IGFBP-3 levels. IGFBP-1/IGF-1 and IGFBP-3/IGF-1 ratios were significantly decreased (approximately - 50%) as a result of resistance training (P<0.05). Thus, IGF-1 bioavailability was increased as a result of resistance training induced increases in IGF-1 levels in older women with low bone mineral density. These alterations in the IGF-1 system may be contributing to the significant strength gain observed with the resistance training in this population.

Osteoblastic metastases from breast carcinoma with false-negative bone scan.

The authors report a case of metastatic breast carcinoma that on investigation was shown to have a negative bone scan in spite of multiple densely sclerotic metastases on radiography and CT and a positive bone biopsy. The literature is reviewed with regard to the subject of negative bone scans in this situation.

Pulmonary nodules: differential diagnosis using 18F-fluorodeoxyglucose single-photon emission computed tomography.

OBJECTIVE: The objective of this study was to prospectively evaluate the feasibility and efficacy of single-photon emission computed tomography (SPECT) with 18F-fluorodeoxyglucose (FDG) for differentiating malignant from benign pulmonary nodules. SUBJECTS AND METHODS: Twenty-six patients with 28 radiologically indeterminate focal pulmonary lesions were examined. Fasting patients were injected with 5 MBq/kg of FDG (maximum dose, 370 MBq). Imaging was performed with dual-head SPECT cameras equipped with 511-keV collimators. RESULTS: Seventeen of 21 pathologically malignant nodules showed FDG uptake on SPECT imaging (sensitivity, 81%). None of the seven benign modules showed uptake (specificity, 100%). SPECT imaging with FDG was positive in all 16 malignant nodules that were larger than or equal to 2 cm in diameter. However, only one (20%) of five nodules smaller than 2 cm in diameter showed positive on SPECT imaging. CONCLUSION: Using current technology, we found FDG SPECT imaging useful for distinguishing benign from malignant pulmonary nodules that were larger than or equal to 2 cm in diameter. However, because of the relatively low sensitivity of SPECT, smaller malignant nodules were not adequately revealed.

Candida osteomyelitis and disc space infection of the lumbar spine.

Candida osteomyelitis is an uncommon complication of immunosuppressive therapy. Its radiographic manifestations are similar to those of other relatively indolent infectious agents. We report the CT and MR findings in a patient who developed this condition following treatment for acute myelogenous leukemia, and review the imaging literature covering similar cases.

Ability of serum prostate-specific antigen levels to predict normal bone scans in patients with newly diagnosed prostate cancer.

OBJECTIVES: To determine whether pretreatment serum prostate-specific antigen (PSA) levels in newly diagnosed prostate cancer patients can identify a group with a low probability of osseous metastasis and safely eliminate the need for a bone scan as a routine part of the staging evaluation. METHODS: We retrospectively reviewed 683 patients with prostate cancer between 1990 and 1993. Patients with prior therapy or serum PSA levels obtained longer than 3 months prior to bone scan were excluded. Bone scans were reviewed by two nuclear medicine physicians with a third deciding equivocal cases. RESULTS: Only 6% of 490 evaluable patients had a positive bone scan on initial evaluation. Scans were positive in 0 of 290 (0%) with PSA levels below 10 micrograms/L, 4 of 88 (4.5%) with PSA levels between 10 and 20 micrograms/L, and 24 of 112 (21%) with PSA levels above 20 micrograms/L. Although the risk of a positive bone scan increased with increasing PSA levels, PSA is a poor positive predictor of positive bone scans. The risk of a positive bone scan was 8% (5 of 64 patients) when PSA was between 20 and 50 micrograms/L, and increased to 40% (19 of 48 patients) for PSA levels greater than 50 micrograms/L. In contrast, serum PSA levels below 10 micrograms/L are strong negative predictors of positive bone scans, with no positive scans in 290 patients with PSA levels below 10 micrograms/L. Although the risk of a positive bone scan increased with increasing stage and grade, tumor stage and grade were poor negative predictors of positive bone scans. Up to 4% of patients with clinically confined or well-differentiated to moderately differentiated tumors had positive scans. Scans were positive in 12% of poorly differentiated tumors, but all these patients had PSA levels above 10 micrograms/L. CONCLUSIONS: Our data support the elimination of routine bone scintigraphy in patients with newly diagnosed prostate cancer and PSA levels below 10 micrograms/L. Bone scans are indicated when PSA levels are above 10 micrograms/L, or with T3 or poorly differentiated disease.

Functional results in oral cavity reconstruction using reinnervated versus nonreinnervated free fasciocutaneous grafts.

Recent advances in free-tissue transfer have given the otolaryngologist--head and neck surgeon a number of reliable options for reconstruction of the oral cavity following ablative procedures. One recent modification has been the transfer of free reinnervated fasciocutaneous grafts in the hope of enhancing oral rehabilitation following surgery. To assess the efficacy of this modification, a protocol was established to retrospectively evaluate patients that received either reinnervated or non-reinnervated free-tissue transfers. Factors including site, surgical resection, type of tissue transfer, and follow-up period were controlled. Evaluation of free-graft sensory return and quality of life was carried out through physical examination and patient interview. Speech assessment was carried out using standardized tests of intelligibility administered by a speech pathologist. Swallowing assessment was carried out with videocinefluoroscopic and scintigraphic techniques, and the oropharyngeal swallow efficiency was calculated. Sensory return in the reinnervate free grafts was superior; however, there was not statistical difference between groups in the speech and swallowing tests. Quality of life was judged to be good in both groups. Sensory return and functional outcome in intraoral reconstruction after tumour ablation was reviewed and discussed

Disseminated intravascular coagulation in a patient with metastatic prostate cancer: fatal outcome following strontium-89 therapy.

A patient with metastatic prostate cancer was found to have low-grade disseminated intravascular coagulation (DIC). He had significant bone pain despite external-beam radiotherapy and was given 89Sr with subsequent thrombocytopenia and epistaxis. The patient died from generalized hemorrhage 36 days postinjection. Although it is not possible to establish a causal relationship between the 89Sr and DIC, practitioners should be alert to complications associated with the primary disorder which might occur at a time to raise concern about the intervention.

Ascending aortic dissection causing unilateral absence of perfusion on lung scanning.

A case of an ascending aortic dissection occurring in a patient 8 years after an aortic valve replacement is presented. The patient's initial clinical presentation was thought to be due to pulmonary embolism, and a ventilation-perfusion lung scan demonstrated mismatched absence of perfusion to the entire right lung. Aortography and findings at surgery demonstrated a type A dissection of the ascending aorta. The anatomic relationship of the aorta and pulmonary artery and their common tunica adventitia make the right pulmonary artery susceptible to extrinsic compression after aortic dissection. Although uncommon, dissection of the ascending aorta needs to be considered in patients who have undergone previous aortic valve surgery and demonstrate mismatched unilateral absence of perfusion to the right lung. Because anticoagulation is contraindicated in patients with acute aortic dissection, confirmation of the diagnosis with angiography usually is required.

The 'hot halo' sign. Pyogenic pericarditis on In-111 leukocyte scintigraphy.

The authors report a patient with diffuse pyogenic pericarditis and focal myoendocarditis initially detected using In-111 WBC scintigraphy. The patient was in septic shock after hemodialysis for the treatment of chronic renal failure. This was preceded by clinical signs and symptoms of pericarditis thought to be viral in nature. Initial investigations found no septic focus, and the patient was referred for In-111 WBC scintigraphy. This revealed a striking "halo" of increased activity around the heart, strongly suggesting bacterial pericarditis. A subsequent pericardiocentesis yielded 400 ml of purulent material, confirming the diagnosis.

Comparison of stress-only vs. stress/rest with technetium-99m methoxyisobutylisonitrile myocardial perfusion imaging.

Unlike conventional thallium-201 myocardial imaging, technetium-99m methoxyisobutylisonitrile (MIBI) requires separate stress and rest injections. We prospectively studied 148 consecutive patients referred for myocardial perfusion studies to determine the diagnostic value of rest images once normal exercise or dipyridamole tomographic images had been obtained. In patients referred with no history of previous myocardial infarction in whom the diagnosis of coronary artery disease was suspected, 45 of 109 (41%) patients had normal stress tomographic images. Obtaining rest images did not alter the final interpretation in any of these cases. From this we infer that in patients with normal images after exercise or dipyridamole administration and no past history of myocardial infarction, 99mTc-MIBI rest images are not required. This provides several advantages including increased speed of diagnosis, decreased patient radiation exposure, improved cost efficiency and decreased demand on tomographic camera time.

Malrotation simulating gallbladder perforation on Tc-99M IDA scintigraphy. Pitfall to avoid.

A patient with upper abdominal discomfort had Tc-99m IDA scintigraphy performed for suspected gallbladder disease. In addition to filling of the bile ducts and the gallbladder, tracer collected in the right side of the abdomen and was thought at first to be the right paracolic gutter, indicating a gallbladder rupture. Discussion with the surgeon and radiographic correlation indicated that the patient did not have gallbladder perforation but, rather, a malrotation of the bowel. This diagnosis became clear on delayed images.

Bilateral subdural hematomas diagnosed with technetium-99m-HMPAO brain SPECT.

An elderly patient with a complex history of organic dementia but a normal neurologic examination had a 99mTc-hexamethylpropylene-amine-oxime (HMPAO) brain scan for a suspected cerebrovascular accident or space-occupying lesion. The study showed no perfusion abnormality in the brain parenchyma, but bilateral flattening and inversion of the normal hemispheric convexities, with separation from the skull was identified. Bilateral subdural hematomas (SDH) were suspected and the patient had a computed tomographic scan that confirmed the diagnosis.

Uptake of maleic hydrazide and related compounds into willow. A comparison between molecular structure and biological activity.

A study has been made of a range of maleic hydrazide (MH) derivatives to compare their molecular structures with what has already been found concerning MH behaviour in willow (Salix viminalis L.). Use was made of two properties of MH, one of which was the ability to become concentrated into root apices of young willow roots (Coupland and Peel, 1971); the other was the ability of MH to inhibit the uptake of uracil into the sieve elements in bark strip material (Coupland and Peel, 1972). As a result of the present investigations it appears that an unsaturated heterocyclic ring system, including the grouping-CH=CH-CO-NH- is essential to retain the characteristics of the MH molecule.

Maleic hydrazide as an antimetabolite of uracil.

When labelled uracil was supplied to the solution bathing the cambial surfaces of bark strips of willow, uptake into the sieve elements took place as evidenced by the appearance of radioactivity in the honeydew of aphids feeding on the strips. When maleic hydrazide (MH) was also applied an inhibition of uracil uptake was observed. However uracil seemed to have no effect on MH uptake. The type of inhibition described above showed similarities to classical competitive inhibitors of enzymes.