Synthesis and evaluation of (18)F-labeled choline analogs as oncologic PET tracers.

UNLABELLED: Elevated levels of choline (trimethyl-2-hydroxyethylammonium) and choline kinase (CK) activity in neoplasms have motivated the development of positron-labeled choline analogs for noninvasive detection of cancer using PET. The aim of this study was to further evaluate [(18)F]fluorocholine (fluoromethyl-dimethyl-2-hydroxyethylammonium [FCH]) as an oncologic probe in comparison with several other closely related molecules. METHODS: FCH, [(18)F]fluoromethyl-methylethyl-2-hydroxyethylammonium (FMEC), [(18)F]fluoroethyl-dimethyl-2-hydroxyethylammonium (FEC), and [(18)F]fluoropropyl-dimethyl-2-hydroxyethylammonium (FPC) were synthesized through [(18)F]fluoroalkylation reactions. In vitro phosphorylation rates of the (18)F-labeled choline analogs and [methyl-(14)C]choline (CH) were studied using yeast CK. Several choline radiotracers were also evaluated in cultured PC-3 human prostate cancer cells. Data on chemical stability, radiation dosimetry, and toxicity of FCH were obtained. PET studies with FCH were performed on a patient with prostate cancer and a patient with a brain tumor. RESULTS: FCH and FMEC revealed in vitro phosphorylation by CK that was similar to that of choline, whereas rates of phosphorylation of FEC and FPC were 30% (P < 0.01) and 60% (P < 0.01) lower, respectively. Accumulations of FCH, CH, and FPC in cultured PC-3 cancer cells were comparable, whereas uptake of FEC was approximately one fifth that of FCH. Dosimetry estimates using FCH biodistribution data in mice indicated that the kidneys are radiation-dose-critical organs for FCH. PET images of a patient with recurrent prostate cancer showed uptake of FCH in the prostatic bed and in metastases to lymph nodes. FCH PET showed uptake in malignancies in a patient with metastatic breast cancer. PET revealed FCH uptake in biopsy-proven recurrent brain tumor with little confounding uptake by normal brain tissues. CONCLUSION: The fluoromethyl choline analog FCH may serve as a probe of choline uptake and phosphorylation in cancer cells, whereas fluoroethyl (FEC) and fluoropropyl (FPC) analogs appear to have relatively poorer biologic compatibility. Preliminary PET studies on patients with prostate cancer and with breast cancer and brain tumor support further studies to evaluate the usefulness of FCH as an oncologic probe.

Synthesis and evaluation of 18F-labeled choline as an oncologic tracer for positron emission tomography: initial findings in prostate cancer.

The up-regulation of rates of choline uptake and phosphorylation in certain malignancies has motivated the development of positron-labeled choline analogues for noninvasive detection of cancer using positron emission tomography (PET). The choline analogue, no-carrier-added [18F]fluoromethyl-dimethyl-2-hydroxyethyl-ammonium (FCH), was synthesized through the intermediate [18F]fluorobromomethane. FCH was evaluated in relationship to 2-[18F]fluoro-2-deoxyglucose (FDG) as an oncological probe in cultured PC-3 human prostate cancer cells, a murine PC-3 human prostate cancer xenograft model, and in PET imaging studies of patients with prostate cancer. FCH was synthesized in 20-40% radiochemical yield and >98% radiochemical purity. Accumulation of FCH and FDG were comparable in cultured prostate cancer cells, whereas only FCH was inhibited (90%) by hemicholinium-3, a specific inhibitor of choline transport and phosphorylation. FCH showed similar biodistribution to [14C]choline in the tumor-bearing mouse, with prominent renal and hepatic uptake. Tumor uptake of FCH was similar to choline and FDG in the mouse model, although tumor:blood ratios were moderately higher for FCH. Initial PET imaging studies in prostate cancer patients showed high uptake of FCH in advanced prostate carcinoma and detection of osseous and soft tissue metastases. FCH uptake by tumors was markedly reduced in patients rescanned during androgen deprivation therapy. It is concluded that FCH closely mimics choline uptake by normal tissues and prostate cancer neoplasms. FCH is potentially useful as a PET tracer for detection and localization of prostate cancer and monitoring effects of therapy.

Elevated cerebrospinal fluid levels of substance P in patients with the fibromyalgia syndrome.

OBJECTIVE: To measure, and seek clinical correlates with, levels of substance P (SP) in the cerebrospinal fluid (CSF) of fibromyalgia syndrome (FMS) patients. METHODS: CSF from 32 FMS patients and 30 normal control subjects was tested for SP by radioimmunoassay. Clinical measures included tender point examination and standardized questionnaires. RESULTS: CSF SP levels were 3-fold higher in FMS patients than in normal controls (P < 0.001), but they correlated only weakly with tenderness found on examination. CONCLUSION: SP is significantly elevated in FMS CSF, but other abnormalities must exist in FMS to more fully explain the symptoms.

Blood products replacements processed in the surgical field.

This article summarizes the main blood products that can be gathered from, treated, and returned to the trauma patient in the operating room. A brief description of the physiology of blood and clotting mechanisms is given. A focus on plasma pheresis is provided, as well as a suggested procedure for plasma collection.

Measurements of fentanyl and sufentanil in blood and urine after surgical application. Implication in detection of abuse.

An increase in cases of death from overdose and abuse from fentanyl or sufentanil is being encountered by the Bexar County Forensic Science Center in San Antonio, Texas. These drugs have been abused almost solely by health care professionals. The fentanyl derivatives cannot currently be detected by routine laboratory drug-screening programs. Forensic toxicology assays that identify the specific analyte must be used. We report a sensitive assay for detection of fentanyl and sufentanil with a detection limit of -0.5 ng/ml. In addition, results from the analysis of urine and blood samples obtained up to 72 h after drug administration to five patients undergoing cardiac bypass surgery who had received either fentanyl or sufentanil are described. The new procedure enables detection of these drugs more readily, in smaller amounts, and for a longer period of time after use than previously possible. We hope this will lead to intervention and treatment in those abusing the drugs.

Removal of Avitene microfibrillar collagen hemostat by use of suitable transfusion filters.

We assessed the ability of two commercial filters (Pall RC100 and Statlabs 20 microns) to filter out Avitene microfibrillar collagen hemostat from suspension. Quantitative determination of the collagen content as well as scanning electron and light microscopy, particle counting, and platelet aggregometry of filtrates revealed that these filters effectively remove potentially thrombogenic particles of Avitene microfibrillar collagen hemostat. The filters removed at least 97% of the total collagen, as determined by hydroxyproline analysis. The collagen that passed through the Pall filter did not pellet upon ultracentrifugation. Scanning electron and light microscopic analysis revealed no Avitene microfibrillar collagen hemostat particulates in the Pall filtrates but did reveal the presence of a significant number of approximately 1- to 8-microns particulates in the Statlabs filtrates. Concentrates of the filtrates from either of the two filters, however, did not promote platelet aggregation. Through ultracentrifugation and infrared analysis, the filtrates were found to consists of soluble, partially denatured collagen. The risk associated with the reintroduction of collagen particulates into the vasculature can be significantly reduced by use of appropriate, currently available blood-transfusion filters.

Surveillance for HIV antibody and antigen in trauma patients.

Studies in a Baltimore emergency room identified the patient with penetrating trauma as having the highest incidence of Human Immunodeficiency Virus Type I (HIV-1) infection. Anonymous testing over a 15-month period of 165 victims of penetrating trauma presenting to the Medical Center Hospital Emergency Center (San Antonio, Texas) revealed a 0% incidence of HIV-1. This data suggests that HIV-1 trauma patient incidence can be expected to vary between specific geographic areas and patient populations served, independent of community-wide AIDS incidence.

Complement activation in shed blood: release of C3a and C5a. Implications for autologous transfusion.

This preliminary data indicates that kinins are activated in blood shed into a wound particularly at the beginning of an operation. Reinfusion of such blood should only be accomplished after the removal of these activated factors.