Prevention of the spread of SARS COV-2 by Rapid Antigenic Tests on the passengers entering an Italian seaport.

Abstract: Out of 38,282 passengers entering Italy at a major seaport, submitted to SARS-CoV-2 rapid antigenic test, 272 (0.6%) resulted positive and 212 (93.4%) were confirmed positive by qRT-PCR, leaving a 0.6% of false positive. Those resident in the area under control of the same Local Health Authority of the seaport were immediately submitted to isolation and investigated for contact tracing, the others notified to their Local Health Authority which did the same in the following day. This procedure was made possible by a full-time dedication of the local healthcare workers who managed all the passengers disembarking around the clock along the months of the emergency.

Radiotherapy and hepatocellular carcinoma: update and review of the literature.

Historically radiotherapy has always played a limited role for the treatment of HCC due to the low tolerance of the liver and the subsequent risk of radiation induced liver disease (RILD). Technologist advancements in radiation planning and treatment delivery such as Stereotactic Body Radiotherapy (SBRT) combined with Image Guided Radiotherapy (IGRT) has allowed us to further increase tumor dose while maximally sparing the surrounding not involved liver. Furthermore, together with the growing knowledge of radiobiological models in liver disease, several mono-institutional retrospective and prospective series are reporting very encouraging results. Therefore, radiotherapy might play a significant role for the treatment of unresectable HCC, alone or combined with other locoregional treatment such as transarterial chemoembolisation (TACE). The rationale for studying this technique is really strong and it should be tested in well designed prospective randomized clinical trials.

Can we decrease the acute proctitis in prostate cancer patients using hyaluronic acid during radiation therapy: a prospective historically controlled clinical study.

BACKGROUND: The purpose of this study was to evaluate the ability of rectal suppository of hyaluronic acid to limit symptoms of acute radiation proctitis in patients with prostate cancer (PC). MATERIALS AND METHODS: From January 2011 to October 2011, 50 consecutive patients, undergoing radiotherapy with radical or adjuvant intent for PC, were invited to use rectal suppository of hyaluronic acid (HA: Cicatridina suppository, Farma-Derma s.r.l., Sala Bolognese, BO, Italy) daily, before radiation delivering. An historical group was used as an external control. Acute rectal toxicity was scored weekly according to RTOG criteria. Time to occurrence of acute rectal toxicity was taken as endpoint. RESULTS: Compliance was good. Only 2% of HA treated patients had a G2 acute proctitis versus 7% of historical group, globally a difference was observed in rate of acute proctitis between the experimental arm and the control group: 32% in experimental arm versus 45% in control group (p = 0.08). A delay in the onset of acute rectal toxicity in patients treated with HA (p = 0.04) was showed. CONCLUSIONS: Our findings suggested the role of HA in reducing acute proctitis in prostate cancer patients treated with radiotherapy. Further trials are needed to confirm these results.

Metabolic responses in non-small cell lung cancer after hypofractionated stereotactic radiotherapy PET and hypofractionated radiotherapy.

BACKGROUND: The aim of our study was to evaluate the pattern of local failure after stereotactic body radiotherapy (SBRT) of non small cell lung cancer (NSCLC) lesions relating to different type of 18F-FDG positron emission tomography (PET) response. METHODS: Thirteen NSCLC patients for a total of 15 lesions (primary early or locally advanced and metastases) underwent PET before and 6 months after SBRT. Maximum standard uptake value (SUVmax) <2.5 was considered as cut off for complete response (CR) while lesion reduction > or =50% with residual value above 2.5 for partial response (PR). RESULTS: With a median follow up of 30 months pre- and post-SBRT mean SUV max values were 8.2 (range 14.2-3.7) and 2.4 (range 12.9-0), respectively. No "in field recurrence" was observed while 3 cases of "out field recurrence" occurred as regional nodes progression at 7.8 and 14 months after treatment. Three years overall survival, local control and distant metastases free survival were respectively 66.7%, 63.3% and 44.4%. Actuarial 75% and 53.3% 3-year local control, 60% and 40% 3-years distant metastases free survival were observed for complete and partial PET response, respectively, after SBRT. Thereafter, 60% and 50% 3-year overall survival were observed for complete and partial response. CONCLUSIONS: Clinical results were significantly better for "responder" than "non responder" and for "complete" than "partial response" group. Moreover, our data seem to confirm that a significant subset of patients maintain a low metabolic activity without developing local relapse on longer follow up.

Does a 6-point scale approach to post-treatment 18F-FDG PET-CT allow to improve response assessment in head and neck squamous cell carcinoma? A multicenter study.

PURPOSE: Response assessment to definitive non-surgical treatment for head and neck squamous cell carcinoma (HNSCC) is centered on the role of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET-CT) 12 weeks after treatment. The 5-point Hopkins score is the only qualitative system available for standardized reporting, albeit limited by suboptimal positive predictive value (PPV). The aim of our study was to explore the feasibility and assess the diagnostic accuracy of an experimental 6-point scale ("Cuneo score"). METHODS: We performed a retrospective, multicenter study on HNSCC patients who received a curatively-intended, radiation-based treatment. A centralized, independent qualitative evaluation of post-treatment FDG-PET/CT scans was undertaken by 3 experienced nuclear medicine physicians who were blinded to patients' information, clinical data, and all other imaging examinations. Response to treatment was evaluated according to Hopkins, Cuneo, and Deauville criteria. The primary endpoint of the study was to evaluate the PPV of Cuneo score in assessing locoregional control (LRC). We also correlated semi-quantitative metabolic factors as included in PERCIST and EORTC criteria with disease outcome. RESULTS: Out of a total sample of 350 patients from 11 centers, 119 subjects (oropharynx, 57.1%; HPV negative, 73.1%) had baseline and post-treatment FDG-PET/CT scans fully compliant with EANM 1.0 guidelines and were therefore included in our analysis. At a median follow-up of 42 months (range 5-98), the median locoregional control was 35 months (95% CI, 32-43), with a 74.5% 3-year rate. Cuneo score had the highest diagnostic accuracy (76.5%), with a positive predictive value for primary tumor (Tref), nodal disease (Nref), and composite TNref of 42.9%, 100%, and 50%, respectively. A Cuneo score of 5-6 (indicative of residual disease) was associated with poor overall survival at multivariate analysis (HR 6.0; 95% CI, 1.88-19.18; p = 0.002). In addition, nodal progressive disease according to PERCIST criteria was associated with worse LRC (OR for LR failure, 5.65; 95% CI, 1.26-25.46; p = 0.024) and overall survival (OR for death, 4.81; 1.07-21.53; p = 0.04). CONCLUSIONS: In the frame of a strictly blinded methodology for response assessment, the feasibility of Cuneo score was preliminarily validated. Prospective investigations are warranted to further evaluate its reproducibility and diagnostic accuracy.

The role of clinicopathologic and molecular prognostic factors in the post-mastectomy radiotherapy (PMRT): a retrospective analysis of 912 patients.

OBJECTIVE: To assess the association of clinicopathologic and molecular features with loco-regional recurrence (LRR) in post-mastectomy breast cancer patients with or without adjuvant radiotherapy (PMRT). PATIENTS AND METHODS: We retrospectively reviewed data of patients undergone to mastectomy followed or not by PMRT between January 2004 and June 2013. The patients were divided according to clinicopathologic and molecular sub-classification features. LRR and Cancer Specific Survival (CSS) were calculated using the Kaplan-Meier method; the prognostic factors were compared using long-rank tests and Cox regression model. RESULTS: A total of 912 patients underwent to mastectomy of whom 269 (29.5%) followed by PMRT and 643 (70.5%) not; among the PMRT group, 77 underwent to the chest wall (CW) and 202 to the chest wall and lymphatic drainage (CWLD) irradiation. The median follow-up was 54 months (range, 3-118). No significant difference in terms of LRR and CSS was found between non-PMRT and PMRT group (p=0.175; and p=0.628). The multivariate analysis of LRR for patients who did not undergo PMRT showed a significant correlation with the presence of extracapsular extension (ECE) (p=0.049), Ki-67>30% (p=0.048) and triple negative status (p=0.001). In the PMRT group, triple negative status resulted as the only variable significantly correlated to LRR (p=0.006) at the multivariate analysis and T-stage also showed a trend to significance (p=0.073). Finally, no difference in LRR control was shown between CW and CWLD-PMRT (p=0.078). CONCLUSIONS: After mastectomy ECE, a cut off of Ki-67>30% and triple negative status were strictly correlated with LRR regardless of clinicopathologic stage. PMRT has a positive impact in decreasing LRR in patients with this molecular profile. Besides, CW might represent a valid option for patients with one to three positive nodes.

Role of perfusion CT in the evaluation of metastatic nodal tumor response after radiochemotherapy in head and neck cancer: preliminary findings.

OBJECTIVE: To assess changes of CT perfusion parameters (ΔPCTp) of cervical lymph node metastases from head and neck cancer (HNC) before and after radiochemotherapy (RT-CT) and their association with nodal tumor persistence. PATIENTS AND METHODS: Eligibility criteria included HNC (Stage III-IV) candidates for RT-CT. Patients underwent perfusion CT (PCT) at baseline 3 weeks and 3 months after RT-CT. Blood volume (BV), blood flow (BF), mean transit time (MTT) and permeability surface (PS) were calculated. PET/CT examination was also performed at baseline and 3 months after treatment for metabolic assessment. RESULTS: Between July 2012 and May 2016, 27 patients were evaluated. Overall, only 3 patients (11%) experienced tumor persistence in the largest metastatic lymph node. A significant reduction of all PCTp values (p<0.0001), except MTT (from 6.3 to 5.7 s; p=0.089), was observed at 3 weeks post-RT-CT compared to baseline. All PCTp values including MTT were significantly lower at 3-month follow-up compared to baseline (p<0.05). Moreover, a statistically significant association was observed between nodal tumor persistence and high BF values (p=0.045) at 3 months after treatment that did not occur for the other parameters. CONCLUSIONS: Our preliminary findings show that all PCTp except MTT are significantly reduced after RT-CT. High BF values at 3 months post-RT-CT are predictive of nodal tumor persistence.

Telomerase activity and hTERT mRNA expression in glial tumors.

Human telomerase is a structurally complex ribonucleoprotein that is responsible for the maintenance of telomeric DNA at the ends of the chromosomes. The enzyme is proposed as having an important role in cell immortalization and oncogenesis. A limited number of studies have been performed on the telomerase system in brain tumors, and these studies are somewhat conflicting. The relative ineffectiveness of current therapies for malignant gliomas led to the need for novel targets for more promising approaches. In order to clarify the prognostic significance of telomerase expression in gliomas and to speculate on therapeutic implications, we examined telomerase activity by the telomeric repeat amplification protocol (TRAP) assay in 42 gliomas, (32 multiform glioblastomas, 4 anaplastic astrocytomas, 4 differentiated astrocytomas, 1 oligoastrocytoma and 1 oligosarcoma). Telomerase messenger expression (hTERT mRNA) was evaluated by reverse transcription-PCR analysis in the same group of tumors. High telomerase activity was detected in 21/42 gliomas (50%). The levels of telomerase in terms of its messenger level expression overlapped the activity; in fact, a significant association between telomerase activity and hTERT mRNA expression was found (chi2 test; p<0.0001). At univariate analysis, advanced age as well as high telomerase activity and hTERT mRNA levels were seen to be significant predictors of worse prognosis regarding both overall survival (p=0.007, p=0.007, p=0.04, respectively) and disease-free interval (p=0.008, p=0.008, p=0.04, respectively). All these variables maintained a significant independent prognostic role in multivariate analysis. Telomerase may represent an indicator of progression and poor prognosis in this type of cancer, with interesting therapeutic implications.

How does radiotherapy impact swallowing function in nasopharynx and oropharynx cancer? Short-term results of a prospective study.

The objective of this study is to report the initial results of a prospective trial assessing instrumental deglutition function in nasopharynx and oropharynx cancers after radio or chemoradiotherapy using intensity-modulated radiotherapy (IMRT). IMRT was delivered aiming to spare the swallowing organ at risk (SWOARs) for Stage II-IV naso- and oropharynx cancer. Objective instrumental assessment included videofluoroscopy (VFS), fiberoptic endoscopic evaluation of swallowing (FEES) and oro-pharyngeal-oesophageal scintigraphy (OPES) at baseline and at 1 month after radiotherapy. Dysphagia parameter scores were calculated at each exam after liquid (L) and semi-liquid (SL) bolus intake: pre-deglutition penetration, aspiration, pharyngeal transit time (PTT) and hypopharyngeal retention index (HPRI). Overall, 20 patients (6 nasophaynx and 14 oropharynx) completed treatment and instrumental assessment after 1 month. Comparison between pre- and post-treatment HPRI score values showed a significant worsening in both FEES-L (p = 0.021) and SL (p = 0.02) and at VFS-L (p = 0.008) and SL (p = 0.005). Moreover, a relationship between HPRI worsening at FEES-L and FEES-SL (p = 0.005) as well as at VFS-L and VFS-SL (p < 0.001) was observed. PTT was not significantly affected by radiotherapy (p > 0.2). Only a few patients experienced pre-deglutition penetration (1 patient with base of tongue cancer at FEES-L and SL) and aspiration (1 patient with nasopharynx cancer at OPES-L and FEES-SL) after radiotherapy. Our early results showed that IMRT-SWOARs sparing caused a significant increase in the post-deglutition HPRI score. Longer follow-up will be necessary to evaluate if the increase of HPRI is related to a high risk of developing late aspiration.

Telomerase in intracranial meningiomas.

Telomere length maintenance is essential for tumorigenesis; most human tumors stabilize their chromosome ends via the activity of a specialized reverse transcriptase, telomerase, that uses the template region of the RNA moiety complementary to the TTAGGG repeat to synthesize one strand of telomeric DNA. Meningiomas are estimated to constitute between 13% and 26% of primary intracranial tumors. The aim of this study was to evaluate telomerase activity and its messenger expression in meningiomas in relation to their different histologic pattern and grade of cytonuclear atypies, which are associated with relapse, and consequently represent the most important parameter for the evaluation of the clinical behavior of this tumor. Telomerase activity was examined by the telomeric repeat amplification protocol (TRAP) assay in 32 meningiomas (26 typical and 6 atypical/anaplastic). Telomerase messenger expression (hTERT mRNA) was evaluated by reverse transcription-PCR analysis in the same group of tumors. Telomerase activity ranged from undetectable to low levels in 19/26 (73%) of typical meningiomas, while all the atypical/anaplastic meningiomas showed medium-high levels of activity (>3 TPG units, median value), (chi(2) test; p=0.001). The levels of telomerase in terms of its messenger level expression overlapped the activity; a significant association between telomerase activity and hTERT mRNA expression was also found (chi(2) test; p=0.01). Moreover, 2 atypical/anaplastic meningiomas of our series relapsed; in these samples we found high levels of telomerase, both in terms of activity and mRNA expression. Telomerase activity and its hTERT mRNA expression tended to increase as the histologic grading of intracranial tumors increased, suggesting a role of telomerase reactivation in the progression of these tumors. Moreover, our results indicate RT-PCR assay as a rapid tool to identify and quantify telomerase RNA in intracranial meningiomas as in other human tumor models.

Hepatitis C virus infection: other biological fluids than blood may be responsible for intrafamilial spread.

BACKGROUND/AIMS: Several epidemiological studies have shown the existence of other routes of transmission of the hepatitis C virus besides the parenteral one, but the mechanisms involved are not yet understood. The general aim of this study was to evaluate the prevalence of hepatitis C virus infection in family contacts of infected patients and to analyze the possible risk factors and alternative transmission routes. METHODOLOGY: One hundred and thirty-eight relatives of 45 patients (index cases) affected by C virus-related chronic hepatitis were studied. The relatives were 45 spouses, 89 children and 4 cohabitants who underwent detection of serum anti-HCV antibodies; the anti-HCV-positive subjects were tested for serum HCV-RNA. The index cases, all the spouses and only other infected relatives were tested for the presence of HCV-RNA in saliva RESULTS: Antibodies to hepatitis C virus were detected in 5.7% of the family members while 11.1% of the analyzed spouses were serum HCV-RNA-positive. HCV-RNA was found in 44% of the examined saliva and 39% of these were found serum HCV-RNA-negative. The prevalence of hepatitis C virus among household contacts, excluding cases with previous parenteral exposure, was 3.6%. CONCLUSIONS: The epidemiological data on the intrafamilial spread of hepatitis C virus may be underestimated owing to the existence of infected relatives serum-negative but saliva-positive for the presence of the virus. The whole of these observations suggests a possible role of biological fluids in intrafamilial spread of hepatitis C virus.

Anaplastic thyroid cancer: a case report of a long term survival patient and review of literature data.

Anaplastic thyroid carcinoma (ATC) is a very rare disease accounting for less than 2% of all thyroid malignancies and associated to a dismal prognosis. The median survival is between 3 to 9 months with less than 10% of patients alive at 3 years after the time of diagnosis. This low cure rate is due to the late clinical presentation as a bulky unresectable tumour mass often associated with synchronous lung metastases (20-50%). A multimodality treatment consisting in a radical surgery followed by radiotherapy and chemotherapy is reported to be associated with better clinical outcomes while young age (< 65 years), tumour size (< 6.5 cm) and absence of distant metastases at time of diagnosis are recognized as strong prognostic factors of survival. We report the case of a 65 year-old man who was referred to our hospital for an ATC which extended to the external right tracheal wall and muscolar layer of esophagus. The patient underwent radical thyroidectomy with bilateral neck dissection followed by 3 cycles of adjuvant chemotherapy (Cisplatin /Epirubicin) and subsequent radiochemotherapy with Cisplatin as radiosensitizer. At more than 6 years since diagnosis the patient is still alive without evidence of local recurrence or distant metastases. Therefore, aggressive multimodality treatment after radical surgery might improve clinical outcomes and perhaps should be tested in prospective clinical trials.

Soluble human leukocyte antigen-g and its insertion/deletion polymorphism in papillary thyroid carcinoma: novel potential biomarkers of disease?

INTRODUCTION: Human leukocyte antigen-G (HLA-G), a nonclassical major histocompatibility complex class I antigen, plays a pivotal role in immune tolerance and a paradoxical role in cancers. AIMS: Our aims were to evaluate plasma soluble HLA-G (sHLA-G) concentrations and the 14-bp insertion/deletion polymorphism of the HLA-G gene in patients with papillary thyroid carcinoma (PTC) or Hashimoto's thyroiditis (HT) and to assess the possible association of these parameters with PTC aggressiveness. METHODS: Samples for the analysis of sHLA-G and +14/-14-bp HLA-G polymorphism were obtained from 121 patients with HT and 183 with PTC; 245 gender- and age-matched healthy subjects served as controls. PTC histopathological aggressiveness was defined according to the last American Thyroid Association guidelines. RESULTS: Positive serum antithyroid antibody titers were observed in 22% of PTC patients and lymphocyte infiltration of thyroid parenchyma at histological examination in 21%, whereas both circulating and histological autoimmunity was detectable in 12% of PTC patients. No differences in the +14/-14-bp polymorphism frequencies were observed between the study groups. The prevalence of detectable sHLA-G was lower in healthy controls (52%) as compared with both HT (57%) and PTC (62%) patients. By stratifying the study groups according to sHLA-G level of positive subjects, significantly higher plasma sHLA-G values in PTC (42.9 ± 3.3 ng/ml; P = 0.002) and HT patients (49.1 ± 2.6 ng/ml; P < 0.002) as compared with healthy controls (8.5 ± 1.8 ng/ml) were obtained. Moreover, PTC patients with detectable plasma sHLA-G levels showed a higher aggressive behavior (P < 0.04) than those without. CONCLUSIONS: Although confirming the frequent association between PTC and chronic autoimmune thyroiditis, these data suggest that elevated circulating sHLA-G levels, besides an important signal of alterations of immune homeostasis, may be considered a potential, novel marker of PTC histopathological aggressiveness at diagnosis. Additional studies are needed to confirm the actual role and clinical relevance of the HLA-G complex in PTC development and progression.

Glioblastoma in elderly patients: safety and efficacy of adjuvant radiotherapy with concomitant temozolomide.

The aim of this study was to evaluate the impact of radiotherapy plus concomitant and adjuvant temozolomide (TMZ), in terms of feasibility and activity, in elderly patients with glioblastoma. From January 2002 to December 2007, 42 consecutive patients with glioblastoma (27 men and 15 women) aged 65 years or more (median age 71.3 years), received radiotherapy plus concomitant and adjuvant TMZ. Nineteen patients (45.2%) had a Karnofsky index >or=80. Thirty-six patients (85.8%) underwent complete or subtotal resection, while 6 patients (14.2%) were only biopsied. All patients received adjuvant radiotherapy within 4 weeks from surgery. Twenty-two patients (54.8%) underwent adjuvant TMZ. Early discontinuation of concomitant TMZ program due to toxicity was observed in 8 patients. Considered variables were: age, Karnofsky index, surgery versus no surgery, radiation dose, and chemotherapy. At a median follow-up of 10.2 months, the 6- and 12-month overall survival rates were 81.9% and 27.8%, respectively. There was a significantly better survival for patients with a performance status according to Karnofsky >80 (p<0.0001). Actuarial progression-free survival at 6- and 12-month was 46.4% and 9.8%, respectively. Globally, the treatment was well tolerated with no treatment-related toxicity in 69% of patients. In conclusion, in elderly patients, the adjuvant chemo-radiotherapy was well tolerated with an acceptable rate of toxicity, and patients with a good performance status had a significantly better survival. However, further prospective trials are needed to confirm these results.

Safety and efficacy of radiotherapy treatment in elderly patients with localized prostate cancer: a retrospective analysis.

The purpose of this study was to evaluate the feasibility and the activity of radiotherapy treatment in patients aged ≥75 with prostate cancer (PC). From January 2000 to December 2007, 107 consecutive patients aged ≥75 years received radiotherapy with radical intent for PC. Eighty-one patients received radiotherapy in combination with a 6 months androgen suppression therapy. Variables considered were age, stage, co-morbidities according to the adult co-morbidity evaluation index (ACE-27) and performance status (PS). The median age was 79.1 years (range 76-87). The 23.4% of patients showed no co-morbidities, while the 46.7% had mild, 23.4% moderate, and 6.5% severe co-morbidities, respectively. All patients completed the planned radiation treatment. At a median follow-up of 37.8 months, the 5-year overall survival rate was 78%. There was a better survival for patients with no or mild co-morbidities (p<0.0001) and a good PS (p=0.009). The actuarial disease-free survival at 60 months was 75.8%. Difference in acute and late toxicity rate was detected between ACE-27 classes for diarrhea and marginally for urinary toxicity, but no difference was detected for different age. We conclude that compliance with radiotherapy is good and rate of toxicity is acceptable in elderly patients. Increasing severity of co-morbidity may sufficiently shorten remaining life expectancy to cancel gains with radical radiotherapy. Further prospective trials are needed to confirm these results.

Safety and feasibility of radiotherapy treatment in elderly non-small-cell lung cancer (NSCLC) patients.

The purpose of this study was to evaluate the feasibility and activity of radiotherapy (RT) treatment in elderly patients with locally advanced lung cancer. From January 2002 to December 2007, 51 consecutive patients (43 men and 8 women) aged > or = 65 received RT for locally advanced lung cancer, 22 with radical intent and 16 in adjuvant setting. Thirty-six patients received chemotherapy. Variables considered were age, co-morbidities, evaluated according to the adult co-morbidity evaluation index (ACE-27), surgery vs. no surgery, radiation dose and chemotherapy. The median age was 74.7 years (range 65-91). Of the patients, 15.7% had no co-morbidity, 41.2% mild, 25.5% moderate, and 17.6% had severe co-morbidities. Sixteen subjects (31.4%) underwent surgery. All patients completed the planned radiation schedule, while chemotherapy was reduced in 16 patients. At a median follow-up of 22 months, the 2- and 3-year overall survival rates were 46.5% and 35.4%, respectively. Patients with no or mild co-morbidities (p < 0.0001) and a good performance status (p < 0.0001) had a better survival. The actuarial progression-free survival at 2 and 3 years was 41.4% and 38.2%, respectively. Acute lung toxicity rates were different between patients with different ACE-27 indexes, whereas late toxicity was not influenced. In conclusion, in elderly patients, the compliance with RT is good and the rate of toxicity is acceptable. Patients with no or mild co-morbidities have a significantly better survival. The increasing severity of co-morbidities may sufficiently shorten the remaining life expectancy, cancel the gains obtained by RT and increase the acute lung toxicity. Further prospective trials are needed to confirm these results.

Differential localization of 5- and 15-lipoxygenases to the nuclear envelope in RAW macrophages.

Leukotriene formation is initiated in myeloid cells by an increase in intracellular calcium and translocation of 5-lipoxygenase from the cytoplasm to the nuclear envelope where it can utilize arachidonic acid. Monocyte- macrophages and eosinophils also express 15-lipoxygenase, which converts arachidonic acid to 15(S)-hydroxyeicosatetraenoic acid. Enhanced green fluorescent 5-lipoxygenase (5-LO) and 15-lipoxygenase (15-LO) fusion proteins were expressed in the cytoplasm of RAW 264.7 macrophages. Only 5-lipoxygenase translocated to the nuclear envelope after cell stimulation, suggesting that differential subcellular compartmentalization can regulate the generation of leukotrienes versus 15(S)-hydroxyeicosatetraenoic acid in cells that possess both lipoxygenases. A series of truncation mutants of 5-LO were created to identify putative targeting domains; none of these mutants localized to the nuclear envelope. The lack of targeting of 15-LO was then exploited to search for specific targeting motifs in 5-LO, by creating 5-LO/15-LO chimeric molecules. The only chimera that could sustain nuclear envelope translocation was one which involved replacement of the N-terminal 237 amino acids with the corresponding segment of 15-LO. Significantly, no discrete targeting domain could be identified in 5-LO, suggesting that sequences throughout the molecule are required for nuclear envelope localization.

Expression of the CYP4F3 gene. tissue-specific splicing and alternative promoters generate high and low K(m) forms of leukotriene B(4) omega-hydroxylase.

Cytochrome P450 4F3 (CYP4F3) catalyzes the inactivation of leukotriene B(4) by omega-oxidation in human neutrophils. To understand the regulation of CYP4F3 expression, we analyzed the CYP4F3 gene and cloned a novel isoform (CYP4F3B) that is expressed in fetal and adult liver, but not in neutrophils. The CYP4F3 gene contains 14 exons and 13 introns. The cDNAs for CYP4F3A (the neutrophil isoform) and CYP4F3B have identical coding regions, except that they contain exons 4 and 3, respectively. Both exons code for amino acids 66-114 but share only 27% identity. When expressed in COS-7 cells, the K(m) of CYP4F3B was determined to be 26-fold higher than the K(m) of CYP4F3A using leukotriene B(4) as a substrate. 5'-Rapid amplification of cDNA end studies reveal that the CYP4F3A and CYP4F3B transcripts have 5'-termini derived from different parts of the gene and are initiated from distinct transcription start sites located 519 and 71 base pairs (bp), respectively, from the ATG initiation codon. A consensus TATA box is located 27 bp upstream of the CYP4F3B transcription start site, and a TATA box-like sequence is located 23 bp upstream of the CYP4F3A transcription start site. The data indicate that the tissue-specific expression of functionally distinct CYP4F3 isoforms is regulated by alternative promoter usage and mutually exclusive exon splicing.