Investigating the functionalization of liposomes with NFL-TBS. 40-63 peptide as a promising drug delivery system.

The NFL-peptide was discovered almost 20 years ago, and its targeting properties were assessed alone or in combination with lipid nanocapsules (LNC), magnetic porous silicon nanorods, or gold nanoparticles. Results highlighted a better targeting of cancer cells, in particular glioblastoma and pancreas cancer. Considering the large use of liposomes (LPs) as an hydrophilic drug delivery system, this study explored the possibility to functionalize liposomes with three different sequences of NFL-peptides: native (NFL-peptide), biotinylated (BIOT-NFL) and coupled to fluorescein (FAM-NFL). Dynamic Light Scattering (DLS) complemented by cryo-electron microscopy (CEM) showed a peculiar ultrastructural arrangement between NFL-peptides and liposomes. Based on this architectural interaction, we investigated the biological contribution of these peptides in LPs-DiD glioblastoma cellular uptake. Flow cytometry complemented by confocal microscopy experiments demonstrated a consequent and systematic increased uptake of LPs-DiD into F98 cells when their surface was decorated with NFL-peptides. The intra-cellular distribution of these liposomes via an organelle tracker indicated the presence of LPs-DiD in lysosomes after 4 h. Based on the properties of this NFL-peptide, we showed in this work the crucial role of NFL peptide as an effective and promising actor to potentiate nanoparticles entry in glioblastoma cell lines.

Metástasis axilares contralaterales en cáncer de mama: ¿Enfermedad sistémica, carcinoma oculto o progresión locorregional? Unidad de Mastología Hospital J.A. Fernández / Contralateral axillary metastases in breast cancer: systemic disease, occult carcinoma, or locoregional progression? Mastology Unit Hospital J.A. Fernandez

Introducción: Las metástasis de los ganglios axilares contralaterales (MAC) en cáncer de mama (CM), son consideradas metástasis a distancia, aunque estudios retrospectivos muestran mejor pronóstico comparado con la enfermedad sistémica. Objetivo: Reportar la estrategia terapéutica de una paciente con CM y MAC metacrónicas. Caso clínico: Paciente de 73 años diagnosticada en 2019 con CM izquierda locorregionalmente avanzado, luminal B like. Realizó neoadyuvancia, con enfermedad clínica estable. Se efectuó cirugía radical, obteniendo respuesta patológica parcial (ypT4bypN2). Cumple radioterapia e inicia hormonoterapia adyuvante. En 2021, presenta una metástasis axilar contralateral aislada. Realizó cirugía axilar, radioterapia y hormonoterapia adyuvante. Discusión: La biología de las MAC es controvertida, pudiendo originarse por drenaje linfático aberrante o por diseminación sistémica. Según AJCC, se consideran metástasis a distancia aunque por su comportamiento clínico podrían abordarse terapéuticamente como enfermedad locorregional. Conclusiones: El pronóstico de las MAC parece ser más favorable que el de la enfermedad sistémica, por lo que el tratamiento con intención curativa estaría ampliamente justificado(AU)

Introduction: Contralateral axillary lymph node metastases (MAC) in breast cáncer (BC) are considered distant metastases, although retrospective studies show a better prognosis compared to systemic disease. Objetivo: To report the therapeutic strategy of a patient with BC and metachronous MAC. Clinical case: 73-year-old patient diagnosed in 2019 with locoregionally advanced left BC, luminal B like. She underwent neoadjuvant therapy, with stable clinical disease. A radical surgery was performed, obtaining a partial pathological response (ypT4bypN2). She completed radiotherapy and started adjuvant hormone therapy. In 2021, She presented an isolated contralateral axillary metastasis and performed axillary surgery, radiotherapy and adjuvant hormonal therapy. Discussion : The biology of MAC is controversial, and may be caused by aberrant lymphatic drainage or systemic dissemination. According to the AJCC, it is considered distant metastasis, although due to its clinical behavior it could be treated therapeutically as locoregional disease. Conclusions: The prognosis of MAC seems to be more favorable than a systemic disease, so treatment with curative intent would be highly justified(AU)

Investigation on the self-assembly of the NFL-TBS.40-63 peptide and its interaction with gold nanoparticles as a delivery agent for glioblastoma.

NFL-TBS.40-63 peptide is a recently discovered peptide derived from the light neurofilament chain (NFL). In this study, we demonstrated that the Biotinylated-NFL-peptide (BIOT-NFL) can spontaneously self-assemble into well-organized nanofibers (approximately 5 nm width and several micrometers in length) in several solutions, whereas the typical self-assembly was not systematically observed from other peptides with or without coupling. The critical aggregation concentration that allows the BIOT-NFL-peptide to aggregate and auto associate was determined at 10-4 mol/L by surface tension measurements. X-ray scattering of BIOT-NFL-peptide also demonstrated its beta-sheet structure that can facilitate the intermolecular interactions involved in the self-assembly process. The possible disassembly of self-assembled BIOT-NFL-peptide-nanofibers was examined via a dialysis membrane study. We further investigated the interaction between nanofibers formed by BIOT-NFL-peptide and gold nanoparticles. Interestingly, a strong interaction was demonstrated between these nanoparticles and BIOT-NFL-peptide resulted in the formation of BIOT-NFL-peptide-nanofibers grandly decorated by gold nanoparticles. Finally, we investigated the internalization of gold nanoparticles coupled with BIOT-NFL-nanofibers into F98 rat glioblastoma cells, which was increased compared to the non-coupled control gold nanoparticles. All these results indicate that this peptide could be a promising therapeutic agent for targeted delivery.

Characterization and quantification of the interaction between the NFL-TBS.40-63 peptide and lipid nanocapsules.

Several studies previously showed that the NFL-TBS.40-63 peptide (NFL-peptide) is capable to specifically penetrating several glioblastoma cell lines (rat, mouse, human) and inhibiting their cell division in vitro and their tumor development in vivo. When lipid nanocapsules (LNCs) are functionalized with the NFL-peptide, their absorption is targeted in glioblastoma cells both in vitro and in vivo. In the present study, we investigated the molecular architecture of these nanovectors (LNC-NFL) by using several microscopy techniques (transmission electron microscopy, cryo-electron microscopy, and cryo-electron tomography). We also used high-performance liquid chromatography (UPLC) technique to evaluate the interaction between LNCs and peptides. The work shows that the NFL-peptide forms stable long filaments along which the lipid nanocapsules interact strongly to form some sort of nanomolecular bracelets. This new construction composed of the NFL-peptide and lipid nanocapsules shows a better internalization in rat glioblastoma cells (F98 cells) than lipid nanocapsules alone.

[Increase rate of ambulatory and management of the care path in breast cancer surgery]. / Augmentation du taux de prise en charge ambulatoire et organisation du parcours de soins en chirurgie sénologique.

OBJECTIVE: To describe practices and impact of ambulatory surgery rate, patient satisfaction after Nursing Support and Post Ambulatory Follow-up Device at Home at the Henri Becquerel Center (DIASPAD CHB) has been set up during surgical management in breast cancer. METHOD: This is a prospective monocentric observational study carried out between January 2017 and December 2018. Patients eligible for the study should undergone breast cancer surgery without reconstruction. Outpatient care was possible if patients met medical, surgical, psychosocial and environmental criteria according to the characteristics of the foreseeable operating suites. We evaluated the progression of the ambulatory hospitalization rate since the DIASPAD CHB beginning and compared the use of this device in conventional and ambulatory hospitalization. RESULTS: Since January 2017, 1312 patients undergone breast cancer surgery without reconstruction. After DIASPAD CHB implementation, ambulatory surgery rate increased from 46 % to 81.7 % for patients operated for breast cancer. The satisfaction rate of patients and nurses was 99 %. CONCLUSION: DIASPAD CHB enabled ambulatory care to take a important share in surgical care in breast cancer by ensuring collaboration between healthcare professionals, anticipation, programming and coordination of care.

Stage IV cutaneous squamous cell carcinoma: treatment outcomes in a series of 42 patients.

BACKGROUND: The prevalence and incidence of cutaneous squamous cell carcinoma (cSCC) are increasing due to the ageing of the population and sun exposure. Advanced cSCC forms (locally advanced and/or locoregional metastatic and/or distant metastatic) account for approximately 3% of cSCC and can result in death. OBJECTIVE: Analysis of the clinical characteristics and treatment outcomes in stage IV cSCC with unresectable locoregional extension and/or the presence of metastases. METHODS: A retrospective study was conducted at a single-centre university hospital for stage IV cSCC patients followed between 1 January 2008 and 31 December 2015. Descriptive analyses (demographic, anatomo-clinical characteristics, treatment sequences, response to treatment and survival analysis) were performed. RESULTS: The study included 42 patients (median age = 75.5 years) with a diagnosis of stage IV cSCC who were treated with at least one line of chemotherapy and/or cetuximab. At the time of diagnosis, 85.7% of the patients had locoregional extension (19% of locally advanced and 67% of locoregional metastatic) and 14.3% had distant metastatic disease. Regarding treatment, 40% and 36% of patients received no more than 1 and 2 systemic treatment lines, respectively. The 4-year overall survival was 6%, and the median follow-up was 18.6 months. The objective response rate was 55% after the first line of treatment with a median progression-free survival (PFS) of 6.18 months and 12% after the second line with a median PFS of 6.51 months. Grade 3 and 4 adverse events were observed for 33% of patients. CONCLUSION: Our study confirms a very poor prognosis of stage IV cSCC and a poor response to conventional therapies, indicating that the stage IV cSCC patient population remains with unmet medical needs.

[Methods of data selection from the French medical information system program for trauma patient's analysis: Burns and traumatic brain injuries]. / Méthodes de sélection des données du PMSI pour l'analyse des victimes de traumatismes : brûlures et lésions cérébrales traumatiques.

BACKGROUND: Data from the French medical information system program in medicine, surgery, obstetrics and dentistry can be adapted in some cases and under certain conditions, to account for hospitalizations for injuries. Two areas have been explored: burn and traumatic brain injury victims. METHODS: An algorithm selecting data from the Medical information system program was established and implemented for several years for the study of burn victims. The methods of selection of stays for traumatic brain injuries, which are the subject of a more recent exploration, are described. RESULTS: Production of results in routine on the hospitalization for burns. Expected production of results on the hospitalization for traumatic brain injuries. CONCLUSION: In both cases, the knowledge obtained from these utilizations of the Medical information system program contributes to epidemiological surveillance and prevention and are useful for health care organization.

Randomised clinical trial: faecal microbiota transplantation for recurrent Clostridum difficile infection - fresh, or frozen, or lyophilised microbiota from a small pool of healthy donors delivered by colonoscopy.

BACKGROUND: Faecal microbiota transplantation (FMT) has become routine in managing recurrent C. difficile infection (CDI) refractory to antibiotics. AIM: To compare clinical response and improvements in colonic microbiota diversity in subjects with recurrent CDI using different donor product. METHODS: Seventy-two subjects with ≥3 bouts of CDI were randomised in a double-blind study to receive fresh, frozen or lyophilised FMT product via colonoscopy from 50 g of stool per treatment from eight healthy donors. Recipients provided stools pre- and 7, 14 and 30 days post-FMT for C. difficile toxin and, in a subset, microbiome composition by 16S rRNA gene profiling. RESULTS: Overall resolution of CDI was 87% during 2 months of follow-up after FMT. Stool samples before FMT had significantly decreased bacterial diversity with a high proportion of Proteobacteria compared to donors. Cure rates were highest for the group receiving fresh product seen in 25/25 (100%), lowest for the lyophilised product 16/23 (78%; P = 0.022 vs. fresh and 0.255 vs. frozen) and intermediate for frozen product 20/24 (P = 0.233 vs. fresh). Microbial diversity was reconstituted by day 7 in the subjects receiving fresh or frozen product. Improvement in diversity was seen by day 7 in those randomised to lyophilised material with reconstitution by 30 days. CONCLUSIONS: Comparative efficacy in faecal microbiota transplantation was observed in subjects receiving fresh or frozen faecal product from the same donors. The lyophilised product had a slightly lowered efficacy compared with fresh product, but it resembled other treatments in microbial restoration 1 month after faecal microbiota transplantation.

Postpartum haemorrhage related early increase in D-dimers is inhibited by tranexamic acid: haemostasis parameters of a randomized controlled open labelled trial.

BACKGROUND: Beneficial effects of tranexamic acid (TA) have been established in surgery and trauma. In ongoing postpartum haemorrhage (PPH), a moderate reduction of blood loss was observed in a previously published randomized controlled trial. Analysis of haemostasis parameters obtained from samples collected as part of this study are presented. METHODS: Women with PPH >800 ml after vaginal delivery were assigned to receive either TA (4 g over 1 h, then 1 g per h over six h) (TA) or not (H). A non-haemorrhagic group (NH), <800 ml blood loss, was included as postpartum reference. At four time-points (enrolment, +30 min, +2 h, +6 h), haemostasis was assessed. Haemostasis assays were performed blinded to group allocation. Data were expressed as median [interquartiles] and compared with non-parametric tests. RESULTS: In H compared with NH group, D-dimers increase (3730 ng ml(-1) [2468-8493] vs 2649 [2667-4375]; P=0.0001) and fibrinogen and factor II decrease were observed at enrolment and became maximal 2 h later. When comparing TA to H patients, the increase in Plasmin-Antiplasmin-complexes at +30 min (486 ng ml(-1) [340-1116] vs 674 [548-1640]; P=0.03) and D-dimers at +2 h (3888 ng ml(-1) [2688-6172] vs 7495 [4400-15772]; P=0.0001) was blunted. TA had no effect on fibrinogen decrease. CONCLUSIONS: This study provides biological evidence of an early increase in D-dimers and plasmin-antiplasmin complexes associated with active post-partum haemorrhage and its attenuation by the early use of a clinically effective high dose of TA, opening the perspective of dose ranging studies to determinate the optimal dose and timing in this setting. CLINICAL TRIAL REGISTRATION: ISRCTN09968140.

[Life-threatening hypercalcemia as the initial presentation of childhood acute lymphoblastic leukemia]. / Hypercalcémie menaçante révélatrice d'une leucémie aiguë lymphoblastique de l'enfant.

Hypercalcemia in childhood acute lymphoblastic leukaemia (ALL) is a well-known but uncommon complication. Here, we report a case of B-ALL in which the first signs were life-threatening hypercalcemia associated with diffuse osteolytic lesions with no hematologic abnormalities. We draw attention to the difficulties formally establishing the ALL diagnosis. Bone marrow examinations must be repeated if necessary. Furthermore, biological, cytogenetic, and molecular aspects need to be investigated. Measurement of intact PTH can exclude hyperparathyroidism. PTHrP is possibly involved in hypercalcemia processes induced by tumor cells. The t(17;19) translocation and its E2A-HLF transcript fusion, which have been thought to be a poor prognostic factor, must be determined. Regarding severe hypercalcemia control, treatment is based on both underlying disease management and serum calcium level reduction with aggressive hydration and if necessary bisphosphonates.

Iron status, iron supplementation and anemia in pregnancy: ethnic differences.

OBJECTIVES: To investigate the anemia prevalence during pregnancy and the use of and response to iron supplementation in a multi-ethnic population as well as the possible association between anemia and birth outcomes (pregnancy duration, birth weight). METHODS: Cross-sectional study conducted in a university hospital (Brussels, Belgium) in 341 women. Hemoglobin, ferritin and iron prescription data were extracted from the patients' electronic dossiers; a questionnaire was used to assess iron intake during pregnancy. RESULTS: Anemia prevalence was higher during the 3rd trimester (24.3%) than in the 1st trimester (6.2%). Arab/Turkish women had a higher prevalence of anemia (9.1%) in the 1st trimester compared to Western women (2.4%; p = 0.044). The frequency of iron prescription was significantly higher among Arab/Turkish (43.7%) compared to Western women (27.9%; p = 0.006). A significantly lower mean birth weight was found among women presenting with anemia in the 1st trimester (3166 g) compared to non anemic women (3442 g; p = 0.036) but no significant difference was detected in mean pregnancy duration between both groups (p = 0.804). CONCLUSIONS: Anemia was more prevalent among Arab/Turkish women in spite of receiving more iron prescriptions than Western women. Efficient iron therapy and intensive follow-up are warranted to decrease the anemia prevalence during pregnancy, especially among non-Western women.

Aspirin chemoprevention in patients with increased risk for colorectal cancer: a cost-effectiveness analysis.

BACKGROUND: Aspirin chemoprevention combined with colonoscopy screening is not cost-effective for the general population. However, the cost-effectiveness of aspirin in individuals with prior adenoma resection has not been evaluated. AIM: To evaluate the cost-effectiveness of aspirin chemoprevention alone and in combination with colonoscopy surveillance in patients with prior adenoma resection. METHODS: A model of the natural history of individuals with a history of endoscopic polypectomy was constructed. Four strategies were compared: (i) no intervention, (ii) routine colonoscopy surveillance, (iii) aspirin chemoprevention alone, and (iv) aspirin therapy combined with colonoscopy. RESULTS: Compared with no intervention, all other strategies were more costly but were associated with gains in years of life saved. Aspirin chemoprevention alone was associated with a gain of 0.0092 years, whereas routine colonoscopic surveillance and combination strategy were associated with further gains in years of life saved (0.0124 and 0.0138 years, respectively). Compared with no intervention, the incremental cost-effectiveness ratio of routine colonoscopy surveillance was $78,226 per year of life saved, and the incremental cost-effectiveness ratio of combination aspirin and colonoscopy was $60,942 per year of life saved. CONCLUSION: Aspirin chemoprevention combined with colonoscopic surveillance in post-polypectomy patients may be considered a cost-effective strategy.

Morphology, homogeneity and functionality of human monocytes-derived macrophages.

Primary cultures of human monocyte-derived macrophages (n = 50) were characterized in order to use this cellular model to establish a proteomic map of macrophages. Peripheral blood mononuclear cells were isolated from healthy donors' blood using density gradient centrifugation. The cell culture quality was checked in respect of several morphological and molecular aspects. The homogeneity and purity of cells was assessed after 12 days' primary culture with phase microscopy, immunocytochemistry and flow cytometry. Monocytes were completely differentiated into macrophages within 12 days as shown by phase microscopy. On day 12, all cells expressed CD68 antigen and were negative for CD3. Flow cytometry experiments showed a purity of the primary culture on day 12, in a range between 76% and 98% of CD14+ cells. The functionality of cells was characterized for the presence of ECE-1 as an intracellular marker and for the presence of MMP-9 as a marker secreted into the culture medium. This study allowed to determine criteria of quality and functionality for the primary culture of monocyte-derived macrophages. Cultures meeting these criteria will be used for the proteomic analysis and the establishment of the reference map.

[Imaging of the painful cervical spine]. / Imagerie du rachis cervical douloureux.

Neck pain can occur in several circumstances: traumatic, spontaneous, associated or not with motion, with or without head or upper limb irradiations. Each case requires appropriate clinical examination and radiographs. CT and MRI can be used to obtain additional information. Myelography and arteriography are exceptionally used. Cervical discography and facet joint arthrography are used therapeutically. After a brief anatomical review, normal and pathological patterns will be reviewed using radiographs. Each circumstance is studied: traumatic, degenerative, inflammatory and tumoral. It is emphasized that discogenic cervico-brachial neuralgia usually has a favorable spontaneous outcome. A special chapter is dedicated to calcifying and ossifying diseases of the cervical spine. Cervico-occipital neuralgia is also discussed.

[Imaging of chronic hip pain in adults]. / Imagerie de la hanche douloureuse chronique de l'adulte.

Adult hip pathologies are mainly represented by the degenerative disease, so called "osteoarthrosis, or more precisely coxarthrosis". The means of imaging are exposed, according to their specific value: X Rays (measurement of the characteristic angles of the adult hip), Arthrography, CT Scanner, Arthro-CT Scanner, MRI, Bone Scintigraphy, Ultrasonography. Clinical findings differentiate a mechanical syndrome and an inflammatory syndrome. The coxarthrosis is the most frequent, under two forms: primary (idiopathic) coxarthrosis and secondary coxarthrosis. Primary (idiopathic) coxarthrosis has a localised narrowing of the joint space, osteophyte formation, subchondral sclerosis, cyst formation. The destruction progresses slowly, in 10 to 15 years leading to a complete destruction. Bilaterality is frequent. it is treated with total hip prosthesis. There is a rapid form (1 to 2 years) (Postel's Disease). Secondary coxarthrosis occurs after architectural vice, chondral diseases, lack of balance between the size of the head and the acetabulum as in the case of previous fracture or dislocation, avascular bone necrosis of the head of the femur, Paget's disease. Calcium pyrophosphate Deposition disease (CPPD) involves mostly aged women, and also leads to cox-arthrosis. Avascular bone necrosis of the head of the femur involves young adults. Bilateral involvement are frequent. MRI is the most sensitive and the most specific means of early diagnosis, The area of bone necrosis appears as well defined modifications of the upper head of the femur, precisely surrounded by a low signal intensity line on both Ti and T2 weighted imaging. MRI shows articular effusion, bone marrow edema. Scintigraphy gives early findings which are a characteristic, but non specific, hot spot. CT scanner is used for hip destruction evaluation. o Algodystrophy: transient osteoporosis of the hip has a cyclic course, lasting 3 to 9 months. MRI shows an inflammatory pattern in the area of the process(dark in Ti and white in T2, with positive Gadolinium response). Scintigraphy is positive. Staphylococcus location in the hip can be acute or chronic. MRI shows joint effusion, cystic formation and subchondral non specific modifications. Tuberculosis of the hip joint is relatively rare. Greater trochanteric tuberculous involvement is possible under special contexts. Chronic Inflammatory diseases are represented by Rheumatoid Arthritis, Spondylarthritis and other chronic inflammatory diseases. Synovial tumors such as Pigmented Villo Nodular Synovitis, Primary Osteochondromatosis, synovial sarcoma have special presentations. The subchondral bone can be involved by amorphous depositions such as in tophaceous gout, different varieties of lipidosis, amyloidosis, reticulo histiocytosis. Pen arthropathies are enthesopathies in the anterior rectus tendon, calcifying tendonitis (not to be confused with calcifying soft tissue tumor/chondrosarcoma). The pelvis bone and the femur are involved by primary and secondary tumors or by insufficiency fractures which can mislead to hip pathologies.

[Radio-anatomy of the knee]. / Radio-anatomie du genou.

The authors review the radiologic anatomy of the knee joint with particular points of interest such as the cruciate ligaments, the menisci, and the articular cartilage. All imaging modalities are shown with special attention regarding MR imaging.

[Pain in the internal knee compartment]. / Douleur du compartiment interne du genou.

The anatomical classification of the traumatic or non traumatic lesion gives a mnemotechnical list which assists in the etiological search for pain of the inner aspect of the knee: skin, sub cutaneous tissue, medial lateral ligament, meniscus, cartilage, sub chondral bone, cruciate ligaments. Each mean of imaging detect specific lesions according to its technical capabilities: standard X Ray film, arthrography, CT scanner, MRI, bone scintigraphy, and echography. In practice, strategy is adapted to the clinical presentation, traumatic or non traumatic. In emergency situations, one is looking for bone, ligamentous, and meniscus lesions. Without acute traumatism, one can discover ligamentous tear sequellae (Pelligrini Stieda's ossifications), transient osteoporosis (algodystrophy), degenerative lesions (arthrosis) of the inner compartment. Always remember "close to the knee", it is necessary to check for more serious infectious or tumoral pathology. If standard plain films remain the first means of examination, and are still useful, MRI is becoming increasingly necessary for a complete anatomical evaluation.

Screening decreases prostate cancer death: first analysis of the 1988 Quebec prospective randomized controlled trial.

BACKGROUND: The 46,193 men aged 45 to 80 years registered in the electoral roll of Quebec City and its Metropolitan area were randomized in November 1988 between screening and no screening in a study aimed of assessing the impact of prostate cancer screening on cause-specific death. METHODS: At first visit, screening included measurement of serum prostatic specific antigen (PSA) using 3.0 ng/ml as upper limit of normal and a digital rectal examination (DRE). Transrectal echography of the prostate (TRUS) was performed only if PSA and/or DRE was abnormal and biopsy was then done, only if PSA was above the predicted PSA value. At follow-up visits, PSA alone was used as prescreening. RESULTS: 137 deaths due to prostate cancer occurred between 1989 and 1996, inclusively, in the 38,056 unscreened men while only 5 deaths were observed among the 8,137 screened individuals. The prostate cancer death rates during the eight-year period were 48.7 and 15 per 100,000 man-years in the unscreened and screened groups, respectively, for a 3.25 odds ratio in favor of screening and early treatment (P < 0.01). CONCLUSIONS: If PSA screening is started at the age of 50 years (or 45 years in the higher risk population), annual or biannual PSA alone is highly efficient to identify the men who are at high risk of having prostate cancer. Coupled with treatment of localized disease, this approach demonstrates, for the first time, that early diagnosis and treatment permits a dramatic decrease in deaths from prostate cancer.

Physiological red blood cell kinetic model to explain the apparent discrepancy between adenosine breakdown inhibition and nucleoside transporter occupancy of draflazine.

A physiological red blood cell (RBC) kinetic model is proposed for the adenosine (ADO) transport into erythrocytes and its subsequent intracellular deamination into inactive inosine (INO) and further breakdown into hypoxanthine (HYPO). The model and its parameters were based on previous studies investigating the kinetics of the biochemical mechanism of uptake and metabolism of ADO in human erythrocytes. Application of the model for simulations of the breakdown of ADO in a RBC suspension revealed that the predicted adenosine breakdown inhibition (ABI) of draflazine corresponded well with the ABI measured ex vivo. The model definitely explained the apparent discrepancy between the ex vivo measured ABI and the nucleoside transporter occupancy of draflazine. Intracellular deamination of ADO rather than its transport by the nucleoside transporter is the rate-limiting step in the overall catabolism of ADO. Consequently, at least 90% occupancy of the transporter by draflazine is required to inhibit adenosine breakdown ex vivo substantially. Simulations on basis of the validated model were performed to evaluate the ABI for different experimental conditions and to mimic the clinical situation. The latter may be very helpful for the design of optimal dosing schemes of draflazine. It was demonstrated that the short half-life of released ADO was prolonged substantially in a dose-related manner after a continuous infusion of draflazine. Finally, the previously found different sigmoidal Emax relationships between the measured ABI and the concentrations of draflazine in plasma and whole blood could be explained by the ADO transport and breakdown RBC kinetic model and the capacity-limited specific RBC binding characteristics of draflazine.

Population analysis of the non linear red blood cell partitioning and the concentration-effect relationship of draflazine following various infusion rates.

AIMS: To investigate the impact of the specific red blood cell binding on the pharmacokinetics and pharmacodynamics of the nucleoside transport inhibitor draflazine after i.v. administration at various infusion rates. It was also aimed to relate the red blood cell (RBC) occupancy of draflazine to the ex vivo measured adenosine breakdown inhibition (ABI). METHODS: Draflazine was administered to healthy volunteers as a 15-min i.v. infusion of 0.25, 0.5, 1, 1.5 and 2.5 mg immediately followed by an infusion of the same dose over 1 h. Plasma and whole blood concentrations were measured up to 120 h post dose, and were related to the ex vivo measured ABI, serving as a pharmacodynamic endpoint. The capacity-limited specific binding of draflazine to the nucleoside transporter located on the erythrocytes was evaluated by a population approach. RESULTS: The estimate of the population parameter typical value (%CV) of the binding constant Kd and the maximal specific binding capacity (Bmax) was 0.385 (3.5) ng ml-1 plasma and 158 (2.1) ng ml-1 RBC, respectively. The non-specific binding was low. The specific binding to the erythrocytes was a source of non-linearity in the pharmacokinetics of draflazine. The total plasma clearance of draflazine slightly decreased with increasing doses, whereas the total clearance in whole blood increased with increasing doses. The sigmoidal Emax equation was used to relate the plasma and whole blood concentration of draflazine to the ex vivo determined ABI. In plasma, typical values (%CV) of Emax, IC50 and Hill factor were 81.4 (1.9)%, 3.76 (9.3) ng ml-1 and 1.06 (3.4), respectively. The relationship in whole blood was much steeper with population parameter typical values (%CV) of Emax, IC50 and Hill factor of 88.2 (2.0)%, 65.7 (2.8) ng ml-1 and 4.47 (5.5), respectively. The RBC occupancy of draflazine did not coincide with the ex vivo measured ABI. The observed relationship between RBC occupancy and ABI was not directly proportional but similar for all studied infusion schemes. CONCLUSIONS: The findings of this study show that the occupancy of the nucleoside transporter by draflazine should be at least 90% in order to inhibit substantially adenosine breakdown in vivo. On the basis of these findings it is suggested that a 15 min infusion of 1 mg draflazine followed by an infusion of 1 mg h-1 could be appropriate in patients undergoing a coronary artery bypass grafting.