Comprehensive characterization of firing byproducts generated from small arms firing of lead-free frangible ammunition

Following the introduction of lead-free frangible ammunition in United States Air Force small arms firing ranges, Combat Arms instructors have routinely reported experiencing adverse health symptoms during live fire training exercises, including sore throat, cough, and headache. Previous studies have found that these symptoms occur despite occupational exposure limits not being exceeded. To better characterize the potential source and mechanisms for health symptoms, a comprehensive characterization of the physicochemical properties of gases and aerosols emitted during the firing of the M9 pistol and M4 rifle using lead-free frangible ammunition was completed. Weapons were fired within a sealed chamber using a remote firing mechanism. A suite of direct-reading instruments and collection-based analytical methods were used to determine the composition of the emissions. Emissions were dominated by carbon monoxide and ultrafine particles. Other prevalent gases included carbon dioxide, ammonia, formaldehyde, hydrogen cyanide, and nitric oxide when measured using Fourier-transform infrared spectroscopy. An electrical, low-pressure impactor showed that, on average, the count median diameter immediately after firing was 36 ± 4 nm (n = 10 rounds) and 32 ± 3 nm (n = 14 rounds) for the M9 pistol and M4 rifle, respectively. Analytical methods were used to determine that emitted particles were primarily composed of soot, copper, and potassium, with trace amounts of calcium, silicon, sodium, sulfur, and zinc. Results from this research confirm prior work and expand upon the characterization of emissions generated from firing lead-free frangible ammunition. By employing multiple methods to measure and analyze data we were able to quantify both total and respirable particle fractions and determine particle morphology and composition. Characterization of the emissions provides insight into potential exposure risks that may lead to the development of adverse health symptoms allowing for the development of strategies for risk mitigation.

Kruppel-like factor 15 is a critical regulator of cardiac lipid metabolism

The mammalian heart, the body's largest energy consumer, has evolved robust mechanisms to tightly couple fuel supply with energy demand across a wide range of physiologic and pathophysiologic states, yet, when compared with other organs, relatively little is known about the molecular machinery that directly governs metabolic plasticity in the heart. Although previous studies have defined Kruppel-like factor 15 (KLF15) as a transcriptional repressor of pathologic cardiac hypertrophy, a direct role for the KLF family in cardiac metabolism has not been previously established. We show in human heart samples that KLF15 is induced after birth and reduced in heart failure, a myocardial expression pattern that parallels reliance on lipid oxidation. Isolated working heart studies and unbiased transcriptomic profiling in Klf15-deficient hearts demonstrate that KLF15 is an essential regulator of lipid flux and metabolic homeostasis in the adult myocardium. An important mechanism by which KLF15 regulates its direct transcriptional targets is via interaction with p300 and recruitment of this critical co-activator to promoters. This study establishes KLF15 as a key regulator of myocardial lipid utilization and is the first to implicate the KLF transcription factor family in cardiac metabolism.

Pre-operative assessment of axillary lymph node status in patients with breast adenocarcinoma using intravenous 99mtechnetium mAb-170H.82 (Tru-Scint AD)

Immunoscintigraphy of the axilla has potential utility for the diagnostic and prognostic assessment of patients with breast adenocarcinoma. mAb-170H.82 is a murine monoclonal antibody (mAb) derived against synthetic Thomsen-Friedenreich (TF) antigen. Tru-Scint AD, a 99mTc-mAb-170H.82 immunoconjugate, has previously been shown to localize in various human adenocarcinomas. The purpose of this study was to evaluate the accuracy of this immunoconjugate in the pre-operative assessment of axillary lymph nodes in patients with known breast adenocarcinoma. Sixteen patients with documented primary breast cancer were injected intravenously with 1 mg of immunoconjugate (radioactivity 1.8 GBq) and imaged 22-24 hrs post-injection. Both planar and single photon emission computed tomographic (SPECT) images were obtained and reviewed in a blinded fashion. Imaging results were compared with surgical and pathological findings. Seven of 16 patients were found to have histologically positive axillary nodes: 5 of these sites were detected by immunoscintigraphy (sensitivity = 71%). Nine patients had pathologically disease-free axillary nodes: only 1 of these was misidentified as positive by immunoscintigraphy (specificity = 89%). These results suggest that immunoscintigraphy with 99mTc-mAb-170H.82 has promise in the detection of axillary lymph node involvement in patients with breast cancer. Further studies are warranted to define the role of immunoscintigraphy in axillary staging.

Problems of delivery of monoclonal antibodies. Pharmaceutical and pharmacokinetic solutions

Monoclonal antibodies to tumour-associated antigens have great theoretical potential for the specific targeting of radioactivity and anti-neoplastic agents to tumours. The clinical success of monoclonal antibody-based cancer diagnosis and therapy depends, however, on solving a number of pharmacokinetic delivery problems. These include: (i) slow elimination of monoclonal antibodies from the blood and poor vascular permeability; (ii) low and heterogeneous tumour uptake; (iii) cross-reactivity with normal tissues; (iv) metabolism of monoclonal antibody conjugates; and (v) immunogenicity of murine forms in humans. As a result of extensive pharmaceutical and pharmacokinetic research conducted over the past 10 to 15 years, several potential solutions to these delivery problems have been identified. Blood concentrations of antibody conjugates may be reduced through regional administration, the use of antibody fragments, interventional strategies and various pre-targeting techniques. Tumour uptake may be increased through administration of higher doses, or the use of agents to increase tumour vascular permeability. Tumour retention of antibody conjugates may be improved by inhibition of metabolism, by using more stable linkage chemistry. Alternatively, normal tissue retention may be decreased through the use of metabolisable chemical linkages inserted between the antibody and conjugated moiety. Very small antigen-binding fragments and peptides that exhibit improved tumour penetration and more rapid elimination from the blood and normal tissues have been prepared by genetic engineering techniques. Chimeric (mouse/human) and human monoclonal antibodies have been developed to circumvent the problem of immunogenicity. Future research will continue to be focused on improvements in the design of monoclonal antibodies for tumour targeting, with the ultimate goal of finally uncovering the 'magic bullet' envisioned by Paul Ehrlich almost a century ago.

Osteopenia in patients with above knee amputation

Using dual energy x-ray absorptiometry, we studied 16 male patients with unilateral above knee amputations (AKA) with a mean age of 48 years (range, 23 to 66 years) who were full-time prosthetic users for more than 5 years. All prostheses were ischial weight bearing. All 16 subjects were found to have normal bone density in their spines and in the normal femurs when compared to nonamputation controls. However, a significant decrease of mean femoral neck bone density was found on the amputated side (0.68g/cm2, range, 0.52 to 1.01) when compared to the normal side (1.01g/cm2, range, 0.75 to 1.20) (p < .05). The mean bone density percentage difference between the two sides was 28% (range, 4% to 48%). There was a significantly negative correlation between the patient's age at the time of amputation and the severity of osteopenia (-0.73; p < 0.05).

Pre-operative localization of 25 consecutive parathyroid adenomas: a prospective imaging/surgical correlative study

The successful diagnosis and surgical treatment of primary hyperparathyroidism due to parathyroid adenoma benefits significantly, in our experience, from a process of pre-operative imaging localization of the parathyroid adenoma. This prospective study evaluates a window of 25 consecutive patients who underwent pre-operative imaging localization prior to successful unilateral parathyroidectomy for parathyroid adenoma. All parathyroid adenomas were successfully localized by imaging, and subsequently documented photographically in surgical correlation, and pathologically confirmed. All patients were cured biochemically. Ultrasound accurately localized 92% of adenomas (100% in the neck and extrathyroidal) while radionuclide subtraction scanning identified 60% of a smaller subset. Both DSA and CT were successful in the two cases utilized, and MRI demonstrated four of five adenomas. The high yield of these pre-operative localization studies should make them an important consideration in the routine evaluation of patients undergoing surgery for possible parathyroid adenoma. Their usefulness in directing a conservative unilateral operation may result in time and cost savings, as well as reduced surgical exposure.

Compartmental analysis of the pharmacokinetics of radioiodinated monoclonal antibody B72.3 in colon cancer patients

Sixteen patients with colorectal cancer were administered 37-74 MBq (1 mg) of radioiodinated B72.3 monoclonal antibody. Pharmacokinetic analysis was carried out on plasma and urine samples. Elimination from the plasma was biexponential with a mean T1/2 alpha of 3.7 h and T1/2 beta of 62.4 h. The plasma clearance was fit to a two-compartmental model. This was combined with a previously reported model for radioiodine to construct a composite model. There was a good correlation (r = 0.952) between the model-predicted and observed excretion of radioiodine suggesting that the composite model is compatible with the pharmacokinetics of the radiolabelled antibody.

Radioimmunodetection of colorectal cancer metastases with 131I-labeled monoclonal antibody B72.3: a pilot study to determine efficacy of detection and pharmacokinetics

We performed radioimmunoscintigraphy (RIS) and/or pharmacokinetic (PCK) studies in 12 patients with primary or metastatic colorectal carcinoma, utilizing an intravenous administration of 1-4 mCi (1 mg) of 131I-B72.3 monoclonal antibody. Metastatic lesions were correctly identified in 4/8 patients by RIS. Two patients with small lesions (> 2 cm diameter) had a false-negative RIS scan. Two patients had a true-negative RIS scan. Optimal images were obtained at 1 week postinjection. PCK studies showed that the plasma clearance of 131I-B72.3 was biexponential with an alpha-phase half-life ranging from 0.5 to 7.1 hr and a beta-phase half-life ranging from 47.5 to 85.3 hr. Systemic and renal clearance data indicated that 131I-B72.3 was cleared very slowly and almost entirely by deiodination. This pilot study was conducted to gain an understanding of the pharmacokinetics of this radiolabeled antibody. On the basis of these data, we are now studying second-generation antibodies as part of our long-range objectives to incorporate them in early detection and treatment protocols.

Hypertrophic pulmonary osteoarthropathy in four patients with interstitial pulmonary disease

The association between digital clubbing and idiopathic pulmonary fibrosis has been well established; however, the simultaneous occurrence of hypertrophic pulmonary osteoarthropathy and interstitial fibrosis, in the absence of neoplastic disease, has only been described in two case reports and was not mentioned in any of 336 patients described in several recent reviews. Among 70 patients referred for investigation of pulmonary infiltrates, four were found to have hypertrophic pulmonary osteoarthropathy associated with interstitial pulmonary disease, in the absence of malignant disease. We conclude that the use of bone scans and roentgenographic examination of the extremities may draw attention to an association between hypertrophic pulmonary osteoarthropathy and idiopathic pulmonary fibrosis.

Pitfall in the investigation of splenic trauma

A patient with suspected splenic trauma is reported in whom, because of an anatomic variant, both radionuclide and sonographic examinations were misleading and led to the erroneous diagnosis of splenic laceration. Confusion arose because of an overlying left lobe of liver and this was clarified by biliary scintigraphy.

Relationship between bone uptake of 99mTc-pyrophosphate and hydroxyproline in blood and urine

In a group of hospital patients with various diseases, the urinary hydroxyproline-to-creatinine ratio showed a significant correlation (r = 0.63; p less than 0.001) with the 5-hr bone-to-soft-tissue ratio for 99mTc-pyrophosphate uptake. In patients on chronic hemodialysis, a similar correlation was found between the 5-hr bone-to-soft-tissue ratio and hydroxyproline levels in plasma and serum. The findings suggest that 99mTc-pyrophosphate binding by bone is related to collagen metabolism.

Observations of radionuclide imaging in hypertrophic pulmonary osteoarthropathy

99mTc pyrophosphate was employed in the study of patients with hypertrophic pulmonary osteoarthropathy. Several facts emerge when comparing the radionuclide, radiographic and clinical findings. Radionuclide imaging reveals the presence and extent of subperiosteal activity with greater clarity than does radiography. Synovitis associated with the syndrome is readily disclosed, and the regression of the skeletal manifestions following excision of the pulmonary lesion can be documented.

Progressive multifocal leukoencephalopathy

The radionuclide, radiographic and pathologic findings in a patient with progressive multifocal leukoencephalopathy were correlated. Radionuclide imaging demonstrated the largest two of the many lesions observed at pathology. On repeated studies, one of the lesions developed a "doughnut" sign due to central necrosis. Cerebral angiography disclosed only one lesion which was initially suggestive of tumor encasement, but four weeks later, this deteriorated into an avascular zone. There were no characteristic features of the lesions demonstrated by radionuclide imaging and cerebral angiography that could be specifically attributed to progressive multifocal leukoencephalopathy.