Word-to-text integration and antecedent accessibility: Eye-tracking evidence extends results of event-related potentials (ERPs).

Eye tracking and event-related potentials (ERPs) have complementary advantages in the study of reading processes. We used eye tracking to extend ERP evidence of Helder et al. (2020) that word-to-text integration at the beginnings and ends of sentences is primarily determined by local text factors (antecedents in a previous sentence) but that global factors (central theme) may make these antecedents more accessible in memory and thus facilitate their integration. The ERP evidence for these conclusions comes from the N400 on a target noun, which varied with the appearance of an antecedent in the previous sentence and whether that antecedent was related to the passage theme. Here, using the same materials, we report eye tracking evidence that reflects not only integration processes indexed by fixation on target words and words following, but also regressions to the antecedent, a measure not possible with ERPs. Interestingly, conclusions from eye-tracking measures align generally with those from Helder et al., but reading times did not consistently correspond to reduced N400s. A distinctive eye-tracking result is that when antecedents were not related to the central theme of the passage (thus less accessible in memory) there was a greater likelihood of return to the antecedent from the regions beyond the target word. These findings demonstrate an independent influence of both local and global context on reading patterns that are unique to eye-tracking measurement, thus both converging with ERP conclusions and adding new ones. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Outcomes, Prognostic Factors and Salvage Treatment for Recurrent Chordoma After Pencil Beam Scanning Proton Therapy at the Paul Scherrer Institute.

AIMS: The outcome of chordoma patients with local or distant failure after proton therapy is not well established. We assessed the disease-specific (DSS) and overall survival of patients recurring after proton therapy and evaluated the prognostic factors affecting DSS. MATERIALS AND METHODS: A retrospective analysis was carried out of 71 recurring skull base (n = 36) and extracranial (n = 35) chordoma patients who received adjuvant proton therapy at initial presentation (n = 42; 59%) or after post-surgical recurrence (n = 29; 41%). The median proton therapy dose delivered was 74 GyRBE (range 62-76). The mean age was 55 ± 14.2 years and the male/female ratio was about one. RESULTS: The median time to first failure after proton therapy was 30.8 months (range 3-152). Most patients (n = 59; 83%) presented with locoregional failure only. There were only 12 (17%) distant failures, either with (n = 5) or without (n = 7) synchronous local failure. Eight patients (11%) received no salvage therapy for their treatment failure after proton therapy. Salvage treatments after proton therapy failure included surgery, systemic therapy and additional radiotherapy in 45 (63%), 20 (28%) and eight (11%) patients, respectively. Fifty-three patients (75%) died, most often from disease progression (47 of 53 patients; 89%). The median DSS and overall survival after failure was 3.9 (95% confidence interval 3.1-5.1) and 3.4 (95% confidence interval 2.5-4.4) years, respectively. On multivariate analysis, extracranial location and late failure (≥31 months after proton therapy) were independent favourable prognostic factors for DSS. CONCLUSION: The survival of chordoma patients after a treatment failure following proton therapy is poor, particularly for patients who relapse early or recur in the skull base. Although salvage treatment is administered to most patients with uncontrolled disease, they will ultimately die as a result of disease progression in most cases.

A Novel Technique of Synthesis of Highly Fluorescent Carbon Nanoparticles from Broth Constituent and In-vivo Bioimaging of C. elegans.

Here we have demonstrated a novel single step technique of synthesis of highly fluorescent carbon nanoparticles (CNPs) from broth constituent and in vivo bioimaging of Caenorhabditis elegans (C. elegans) with the synthesized CNPs has been presented. The synthesized CNPs has been characterized by the UV-visible (UV-Vis) absorption spectroscopy, transmission electron microscopy (TEM) and Raman studies. The sp (2) cluster size of the synthesized samples has been determined from the measured Raman spectra by fitting it with the theoretical skew Lorentzian (Breit-Wigner- Fano (BWF)) line shape. The synthesised materials are showing excitation wavelength dependent tunable photoluminescence (PL) emission characteristics with a high quantum yield (QY) of 3 % at a very low concentration of CNPs. A remarkable increase in the intensity of PL emission from 16 % to 39 % in C. elegans has also been observed when the feeding concentration of CNPs to C. elegans is increased from 0.025 % to 0.1 % (w/v). The non-toxicity and water solubility of the synthesized material makes it ideal candidate for bioimaging.

An observational study of complications in chickenpox with special reference to unusual complications in an apex infectious disease hospital, Kolkata, India.

BACKGROUND: Chickenpox can cause serious complications and even death in persons without any risk factors. AIMS: To observe the different complications with special reference to unusual complications of chickenpox and their outcomes. MATERIALS AND METHODS: The present study was a prospective observational study where 300 patients suffering from chickenpox were evaluated with special reference to unusual complications and outcomes. RESULTS: The usual complications of chickenpox commonly observed were acute hepatitis in 30 (10%) and cerebellar ataxia in 22 patients (7.3%), whereas common unusual complications were acute pancreatitis in 45 (15%), hemorrhagic rash in 10 (3.3%), Guillain-Barrι syndrome in 4 (1.3%), disseminated intravascular coagulation in 4 (1.3%), necrotizing fasciitis in 4 (1.3%), and acute renal failure in 3 patients (1%). It had been observed that most of these unusual complications occurred in patients without any risk factor. A total of 18 patients (6%) died in this study and of them 12 patients (4%) died due to unusual complications. CONCLUSIONS: Compulsory childhood varicella vaccination including vaccination of risk groups and susceptible individuals are all essential to reduce the incidence of chickenpox, associated complications, and subsequent death.

Mature neurons: equipped for survival.

Neurons completely transform how they regulate cell death over the course of their lifetimes. Developing neurons freely activate cell death pathways to fine-tune the number of neurons that are needed during the precise formation of neural networks. However, the regulatory balance between life and death shifts as neurons mature beyond early development. Mature neurons promote survival at all costs by employing multiple, often redundant, strategies to prevent cell death by apoptosis. This dramatic shift from permitting cell death to ensuring cellular survival is critical, as these post-mitotic cells must provide neuronal circuitry for an organism's entire lifetime. Importantly, as many neurodegenerative diseases afflict adult neuronal populations, the survival mechanisms in mature neurons are likely to be either reversed or circumvented during neurodegeneration. Examining the adaptations for inhibiting apoptosis during neuronal maturation is key to comprehending not just how neurons survive long term, but may also provide insight for understanding how neuronal toxicity in various neurodegenerative diseases may ultimately lead to cell death.

Towards monitoring real-time cellular response using an integrated microfluidics-matrix assisted laser desorption ionisation/nanoelectrospray ionisation-ion mobility-mass spectrometry platform.

The combination of microfluidic cell trapping devices with ion mobility-mass spectrometry offers the potential for elucidating in real time the dynamic responses of small populations of cells to paracrine signals, changes in metabolite levels and delivery of drugs and toxins. Preliminary experiments examining peptides in methanol and recording the interactions of yeast and Jurkat cells with their superfusate have identified instrumental set-up and control parameters and online desalting procedures. Numerous initial experiments demonstrate and validate this new instrumental platform. Future outlooks and potential applications are addressed, specifically how this instrumentation may be used for fully automated systems biology studies of the significantly interdependent, dynamic internal workings of cellular metabolic and signalling pathways.

Outcomes of respiratory diphtheria in a tertiary referral infectious disease hospital.

BACKGROUND: Diphtheria is a fatal disease and may cause serious complications if not recognized early and treated properly. OBJECTIVES: To study the epidemiology, clinical features, complications, and outcomes in respiratory diphtheria. MATERIALS AND METHODS: Diphtheria cases admitted in the infectious disease hospital, Beliaghata, Kolkata, India between January 2009 to January 2011 were evaluated in respect to demographic profile, immunization status, clinical features, complications, and outcomes. RESULTS: 200 diphtheria cases were studied. 150 (75%) patients had history of an adequate immunization, and 100 (50%) patients were from lower socio-economic groups. Common clinical features observed were throat pain in 148 (74%) cases and fever in 112 (56%) cases. Complications observed were myocarditis in 136 (68%) cases, neuropathy in 30 (15%) cases, and respiratory compromise in 14 (7%) cases. Death occurred in 5 (2.5%) patients. CONCLUSIONS: diphtheria is still a public health problem in many developing countries. Strict public health measures like an increased immunization coverage, improvement of socio-economic status, easy availability of anti-diphtheritic serum (ADS), early recognition and effective treatment-all may reduce the incidence and mortality.

Mechanism of induction of follicular atresia after equine chorionic gonadotrophin (eCG) antisera treatment in hypophysectomized eCG-injected hamster model: possible involvement of c-myc and cdc25.

An intracellular mechanism of induction of apoptosis of granulosa cells implicated in the initiation of experimentally induced atresia of ovarian follicle in hypophysectomized eCG-injected hamster followed by eCG-antisera treatment is proposed. Induction of atresia after withdrawal of injected eCG by eCG-antisera treatment is possibly caused by inadequate level of the gonadotropin-induced growth factor that results in apoptosis of granulosa cells associated with the activation of c-myc requiring cdc25A.

Asymmetry in the disconfirmation of expectations for natural yogurt.

Effects of expectations conveyed by a product description or an empty package on the evaluation of four types of natural yogurt were studied in a laboratory setting. Hedonic and perceptual responses for the correctly or incorrectly identified products generally showed assimilation: they fell between the responses to the unlabelled products and the responses for the expected properties evoked by presenting only product descriptions or empty packages. Hedonic judgments remained close to the expectation when the product performed better than expected, whereas they were relatively close to the evaluation for the unlabelled product when the product performed worse than expected. The asymmetry was largest for the buying intentions of subjects who received product packages. This is in accordance with the theory that positive disconfirmations are regarded as "gains" and negative disconfirmations as "losses". The asymmetry is likely to be more important in actual buying behaviour than in the experimental settings generally studied, as here.

Protein synthesis rate measured with L-[1-11C]tyrosine positron emission tomography correlates with mitotic activity and MIB-1 antibody-detected proliferation in human soft tissue sarcomas.

Protein synthesis rate (PSR) can be assessed in vivo using positron emission tomography with L-[1-11C]tyrosine (TYR-PET). Biological activity of soft tissue sarcomas (STS) can be measured in vitro by the mitotic rate and number of proliferating cells. In STS the grade of malignancy, in which the mitotic index plays a major role, is considered to be the major standard in predicting biological tumour behaviour. This study was designed to test the validity of TYR-PET in relation to different histopathological features. In 21 patients with untreated STS, the PSR was measured using TYR-PET. The number of mitoses was counted and tumours were graded according to the grading system of Coindre et al. (Cancer 1986; 58:306-309). Proliferative activity was assessed by immunohistological detection of the Ki-67 nuclear antigen using MIB-1 monoclonal antibody. To test the association between the PSR and these tumour parameters, a correlation analysis was performed. A significant (P<0.05) correlation was found between PSR and the Ki-67 proliferation index (R = 0.54), and between PSR and mitotic rate (R = 0.64). There was no correlation between PSR and tumour grade. The present study in malignant soft tissue tumours relates in vivo tumour metabolism as established with TYR-PET to tumour activity measured in vitro and indicates that the non-invasive method of TYR-PET can estimate the mitotic and proliferative activity in STS.

FDG and L-[1-11C]-tyrosine imaging of soft-tissue tumors before and after therapy.

UNLABELLED: This study was undertaken to investigate the relationship of PET using fluorodeoxyglucose (FDG) or L-[1-11C]-tyrosine (TYR) with histopathologic findings in soft-tissue tumors, before and after therapy. Histopathologic parameters that were studied were tumor grade, mitotic rate, proliferation activity and amount of necrosis. METHODS: PET with either FDG or TYR was performed in 55 patients with a lesion suspected to be a malignant soft-tissue tumor. In 28 patients, a second PET study was performed after therapy. Metabolic rate of glucose consumption (MRglc) and protein synthesis rate (PSR) were calculated. Histologic parameters were obtained from a biopsy specimen that was taken just after the first PET study and from the tumor remnant that was resected after therapy. RESULTS: MRglc correlated with tumor grade (r = 0.71) and mitotic rate (r = 0.68) but not with proliferation or necrosis. After therapy, there was no longer a correlation with mitotic rate. PSR correlated with tumor grade (r = 0.53), mitotic rate (r = 0.73) and proliferation (r = 0.66). After therapy, correlation with mitosis and proliferation had improved, and a negative correlation was found between PSR and necrosis (r = -0.74). CONCLUSION: These results validate the use of both FDG and TYR to give an in vivo indication of histologic tumor parameters. However, FDG gives a better indication of tumor grade, whereas TYR is more accurate in predicting mitotic rate and proliferation, especially after therapy. FDG may therefore not be the most suited tracer for monitoring therapy. TYR might be more appropriate for that purpose.

L-[1-11C]-tyrosine PET to evaluate response to hyperthermic isolated limb perfusion for locally advanced soft-tissue sarcoma and skin cancer.

UNLABELLED: PET with L-[1-11C]-tyrosine (TYR) was investigated in patients undergoing hyperthermic isolated limb perfusion (HILP) with recombinant tumor necrosis factor alpha (rTNF-alpha) and melphalan for locally advanced soft-tissue sarcoma and skin cancer of the lower limb. METHODS: Seventeen patients (5 women, 12 men; age range 24-75 y; mean age 52 y) were studied. TYR PET studies were performed before HILP and 2 and 8 wk afterwards. The protein synthesis rates (PSRs) in nanomoles per milliliter per minute were calculated. After final PET studies, tumors were resected and pathologically examined. Patients with pathologically complete responses (pCR) showed no viable tumors after treatment. Those with pathologically partial responses (pPR) showed various amounts of viable tumors in the resected tumor specimens. RESULTS: Six patients (35%) showed a pCR and 11 patients (65%) showed a pPR. All tumors were depicted as hot spots on PET studies before HILP. The PSR in the pCR group at 2 and 8 wk after perfusion had decreased significantly (P < 0.05) in comparison to the PSR before HILP. A significant difference was found in PSR between the pCR and pPR groups at 2 and at 8 wk (P < 0.05). Median PSR in nonviable tumor tissue was 0.62 and ranged from 0.22 to 0.91. With a threshold PSR of 0.91, sensitivity and specificity of TYR PET were 82% and 100%, respectively. The predictive value of a PSR > 0.91 for having viable tumor after HILP was 100%, whereas the predictive value of a PSR < or = 0.91 for having nonviable tumor tissue after HILP was 75%. The 2 patients in the pPR groups with a PSR < 0.91 showed microscopic islets of tumor cells surrounded by extensive necrosis on pathological examination. CONCLUSION: Based on the calculated PSR after HILP, TYR PET gave a good indication of the pathological outcome. Inflammatory tissue after treatment did not interfere with viable tumor on the images, suggesting that it may be worthwhile to pursue TYR PET in other therapy evaluation settings.

Positron emission tomography for staging of oesophageal and gastroesophageal malignancy.

Positron emission tomography (PET) with [18F]-fluoro-2-deoxy-D-glucose (FDG) was prospectively investigated as a means of detecting metastatic disease in patients with oesophageal tumours and compared with computerized tomography (CT), with the surgical findings as a gold standard. Twenty-six patients with a malignant tumour of the oesophagus or gastroesophageal junction underwent CT and PET of the chest and the abdomen. Seven patients underwent laparoscopy to establish resectability. Fifteen patients underwent laparotomy without prior laparoscopy. Four patients did not undergo surgery. The primary tumour was visualized in 81% of patients with CT and in 96% with PET. Neither CT nor PET were suited to assess the extent of wall invasion. Surgically assessed nodal status corresponded in 62% with CT and in 90% with PET. Distant metastases were found in five patients with CT and in eight with PET. The diagnostic accuracy of CT in determining resectability was 65% and for PET 88%. For CT and PET together this was 92%. The present study indicates that FDG-PET can be of importance for staging patients with oesophageal tumours. PET has a higher sensitivity for nodal and distant metastases and a higher accuracy for determining respectability than CT. PET and CT together would have decreased ill-advised surgery by 90%.

L-[1-carbon-11]tyrosine imaging of metastatic testicular nonseminoma germ-cell tumors.

UNLABELLED: The aim of this study was to investigate whether PET with L-[1-11C]tyrosine C(TYR) can be used to visualize metastatic disease of nonseminoma testicular germ-cell tumors and to monitor the effect of systemic cisplatinum-based polychemotherapy in a noninvasive fashion to reduce the number of operations in patients with a residual retroperitoneal tumor mass. METHODS: Ten patients with retroperitoneal nonseminoma testicular germ-cell tumors metastases were studied with TYR PET before the start of cisplatinum-based polychemotherapy. A dose of 370 MBq of TYR was injected intravenously, and a 30-min TYR image was acquired 20 min after injection. The standardized uptake value of TYR was calculated in visualized lesions. RESULTS: PET showed increased focal uptake of TYR in the retroperitoneum of 2 patients (20%). In 2 patients with large and inhomogeneous lesions on CT, PET showed decreased TYR uptake at the site of the lesion (20%). In the other 6 patients, the metastatic tumor masses were not depicted (60%). Because of these disappointing results, no posttreatment scans were obtained. Standardized uptake values of the visualized lesions varied from 1.05 to 2.87 for the lesions with increased metabolism and from 0.29 to 0.34 for lesions with decreased metabolism. CONCLUSION: PET with TYR is not suited to visualize the apparently slowly proliferating nonseminoma testicular germ-cell tumors or determine the nature of a residual retroperitoneal mass after chemotherapy.

Ovarian transforming growth factor-beta (TGF-beta) receptors: in-vitro effects of follicle stimulating hormone, epidermal growth factor and TGF-beta on receptor expression in human preantral follicles.

The expression patterns of transforming growth factor (TGF)-beta receptor type I (TbetaRI) and -II (TbetaRII) in pre- and post-menopausal human ovaries, and the in-vitro effects of follicle stimulating hormone (FSH), epidermal growth factor (EGF) and transforming growth factor-beta1 (TGF-beta1) on receptor expression in preantral follicles were evaluated using immunohistochemistry and immunoblotting. Both types of receptor were present in granulosa, theca and interstitial cells; however, more mural than antral granulosa cells were TbetaRII positive. Overall, more cells expressed TbetaRI than TbetaRII. TbetaRI and TbetaRII expressions were detected in the membrane as well as in the soluble fractions. However, marked increases in TbetaRII and TbetaRI expression in the soluble fraction and corresponding decreases in the membrane fraction were noted in the post-menopausal ovary. Preantral follicles in class 1 and 2 responded in vitro to FSH and EGF with increased growth and a corresponding increase in TbetaRII expression in granulosa cells; however, TGF-beta did not influence follicular growth or receptor expression. There was no apparent change in follicular TbetaRI immunoreactivity regardless of test factors or follicular growth status. These results suggest that TbetaRI and TbetaRII are expressed differentially in human ovarian cells, particularly in the granulosa cells. The shift in TbetaR-I and -II from transmembrane to soluble fraction after menopause indicates that the endocrine milieu provided by the granulosa cells positively influences receptor induction in the membrane and, hence, the biological action of TGF-beta. FSH- and EGF-induced preantral follicular development is associated with a selective induction of TbetaRII and may indicate a mechanism whereby gonadotrophins and growth factor(s) regulate preantral folliculogenesis.

Fluorine-18-fluorodeoxyglucose assessment of glucose metabolism in bone tumors.

UNLABELLED: In our study, we investigate the glucose metabolism of various types of bone lesions with 18F-fluorodeoxyglucose (FDG) PET. METHODS: Twenty-six patients showing clinical and radiographic symptoms of a malignant bone tumor were included. Histological examination after the PET study revealed 19 malignant and 7 benign tumors. PET images were corrected for attenuation. Arterial blood samples were taken to establish the input function. The metabolic rate of glucose consumption (MRglc) was calculated for the whole tumor, for the 10 pixels with maximum activity and for contralateral normal muscle tissue. RESULTS: All lesions were clearly visualized with 18F-FDG PET except for a small infarction of the humerus. All the other lesions had increased glucose metabolism compared to surrounding and contralateral muscle tissue. Both maximum and average MRglc for benign, as well as malignant, lesions were significantly higher than for contralateral normal tissue. The maximum and average MRglc were not higher for malignant as opposed to benign lesions. There was a large overlap between the MRglc of benign and malignant lesions. CONCLUSION: Fluorine-18-FDG PET appears suitable to visualize bone tumors. With the quantification of glucose metabolism, it is not possible to differentiate between benign and malignant bone tumors. There does not seem to be a clear correlation between the MRglc and the biologic aggressiveness of the neoplasms.

Detection of unknown occult primary tumors using positron emission tomography.

BACKGROUND: The potential of positron emission tomography (PET) with 18F-fluoro-2-deoxy-D-glucose (FDG) to detect primary tumors after unsuccessful conventional diagnostic workup was assessed in patients with metastatic disease from an unknown primary tumor. METHODS: Twenty-nine patients with various histologic types of metastases from an unknown primary site were studied after unsuccessful conventional diagnostic workup. The patients received 370 megabecquerels (MBq) (10 millicuries) FDG intravenously and whole body scans were made after 30 minutes after injection onward. RESULTS: All but one known metastatic tumor sites were visualized. Additional metastases were discovered in five patients. With FDG-PET the primary tumor was identified in 7 patients (24%): in 2 patients with carcinoma of the nasopharynx, in 1 patient with plasmacytoma of the base of the tongue, in 1 patient with carcinoma of the lung, in 1 patient with carcinoma of the colon, and in 2 patients with breast carcinoma. FDG-PET did not identify a primary tumor in the remaining 22 patients (76%). Despite a negative PET study, the primary lesion was identified in a later phase in 3 of these patients (14%). Survival was not altered by discovery of the primary tumor. CONCLUSIONS: A previously unknown primary tumor was able to be identified with FDG-PET in 7 of 29 patients after an unsuccessful conventional diagnostic workup. However, the clinical relevance of PET information in this setting is limited.

Standardized uptake value and quantification of metabolism for breast cancer imaging with FDG and L-[1-11C]tyrosine PET.

UNLABELLED: The aims of the study were to compare the value of L-[1-11C]tyrosine (TYR) and [IBF]fluoro-2-deoxy-D-glucose (FDG) as tumor tracers in patients with breast cancer, to investigate the correlation between quantitative values and standardized uptake values (SUVs) and to estimate the value of SUVs for the evaluation of therapy. METHODS: Eleven patients with one or more malignant breast lesions and two patients with one or more benign breast tumors were studied with TYR and FDG. Doses of 300 MBq of TYR and 230 MBq of FDG were given intravenously. All PET sessions were performed using a Siemens ECAT 951/31 camera. Of 10 malignant tumors and the 3 benign lesions, glucose consumption and protein synthesis rate were quantified. All lesions were studied using SUVs based on body weight, body surface area and lean body mass, with and without correction for plasma glucose or tyrosine levels. RESULTS: All malignant tumors were visualized with both FDG and TYR, but the visual contrast was better with FDG. Increased uptake of the tracers was seen in patients with fibrocystic tissue and complicated the visual assessment and the outlining of tumor tissue. Uptake in fibrocystic disease was more prominent with FDG than with TYR. No difference in tumor/nontumor ratio between the two tracers could be established. FDG showed a false-positive result in one benign lesion. No major differences between the SUVs as defined above were found, although the best correlation between glucose consumption and the SUV was observed when the SUV was based on body surface area and corrected for plasma glucose level (r = 0.85-0.87). The SUV based on lean body mass was found to correlate best with protein synthesis rate (r = 0.83-0.94). CONCLUSION: In this group of patients, TYR appears to be a better tracer than FDG for breast cancer imaging, because of lower uptake in fibrocystic disease. SUVs correlate well with quantitative values, but future studies must determine whether treatment evaluation is also reliable with SUVs.

Detection of unknown primary head and neck tumors by positron emission tomography.

The purpose of this study was to investigate the potential of using positron emission tomography (PET) with 18F-labeled fluoro-2-deoxy-D-glucose (FDG) to detect unknown primary tumors of cervical metastases. Thirteen patients with various histologic types of cervical metastases of unknown primary origin were studied. Patients received 185-370 MBq FDG intravenously and were scanned from 30 min after injection onward. Whole-body scans were made with a Siemens ECAT 951/31 PET camera. PET identified the primary tumor in four patients: plasmocytoma, squamous cell carcinoma of the oropharynx, squamous cell carcinoma of the larynx, and bronchial carcinoma, respectively. All known metastatic tumor sites were visualized. PET did not identify a primary tumor in one patient in whom a squamous cell carcinoma at the base of the tongue was found in a later phase. In the remaining eight patients, a primary lesion was never found. The follow up ranged from 18 to 30 months. A previously unknown primary tumor can be identified with FDG-PET in approximately 30% of patients with cervical metastases. PET can reveal useful information that results in more appropriate treatment, and it can be of value in guiding endoscopic biopsies for histologic diagnosis.

PET with L-[1-carbon-11]-tyrosine to visualize tumors and measure protein synthesis rates.

UNLABELLED: We studied the potential of PET with L-[1-11C]-tyrosine (TYR) to visualize tumors outside the central nervous system and to quantify their protein synthesis rates (PSRs). METHODS: Twenty-two patients suspected of having a malignant tumor underwent a PET study with TYR before biopsy. The PSR in nanomoles per milliliter tumor tissue per minute as well as the PSR in contralateral normal tissue, standardized uptake values (SUVs) and tumor-to-nontumor-ratios (T/N ratios) were calculated. RESULTS: Fifteen of the 16 malignancies (94%) were correctly visualized as a hot spot. A chondrosarcoma of the sacrum was not visualized. Of the six patients with benign lesions, cold spots were correctly identified in four (67%). A benign schwannoma and an intramuscular hemangioma of the forearm were visualized as hot spots. PSR in tumor tissue was higher than in the corresponding contralateral normal tissues. PSR and SUV in malignant tumors were higher than in benign tumors. CONCLUSION: TYR appears to be a good tracer for imaging malignancies. The PSR, which was higher in malignant tumors than in normal tissue and the studied benign lesions, could be quantified and correlated with the SUV.