L'acacia au Sénégal

On dénombre, au Sénégal, une douzaine d'espèces indigènes du genre #Acacia (#Fabaceae Mimosoideae). A cette liste, il convient d'adjoindre #Faidherbia albida (Del.) A. Chev. (= #Acacia albida Del.), espèce proche des acacias sensu stricto mais qui s'en sépare par une somme de caractères floraux, palynologiques, ontogéniques, biochimiques, phénologiques. Deux sous-genres d'acacias (sur les 3 reconnus par Vassal, 1972) sont ici représentés : #Acacia (= série #Gummiferae Benth.), groupe notamment caractérisé par la présence d'épines stipulaires (#A. nilotica subsp. #tomentosa et subsp. #adstringens, #A. seyal, #A. ehrenbergiana, #A. tortilis subsp. #raddiana, #A. sieberana var. #sieberana et var. #villosa); #Aculeiferum Vas. (= séries #Vulgares et #Filicinae Benth.) marqué en particulier par la présence d'aiguillons épars (espèces à tendance sarmenteuse : #A. ataxacantha, #A. macrostachya, #A. kamerunensis) ou infrastipulaires (généralement par 2 : #A. polyacantha subsp. #campylacantha ; par 1-3 : #A. dudgeoni, #A. senegal). Sur le plan écologique, ces différents acacias colonisent les domaines sahélien et soudanien, mordant en partie, au nord, sur le domaine saharien (#A. tortilis subsp. #raddiana, #A. ehrenbergiana), au sud sur le domaine guinéen (#A. kamerunensis). Ils sont généralement des éléments marquants du paysage, des steppes septentrionales aux formations boisées du sud. Plusieurs d'entre eux jouent un rôle socio-économique important voire décisif (#Faidherbia albida, arbre fourrager fertilisateur des sols ; #A. senegal, source de la meilleure gomme arabique ; #A. nilotica$, fournisseur de tanin et de bois de feu, etc.). Ceci justifie leur protection et leur emploi dans différents programmes de plantation et d'aménagement sylvo-pastoral pour pallier notamment les effets de la désertification dans la partie sahélienne du pays. (Résumé d'auteur

Premiers essais de comportement de quelques espèces d'Acacias gommiers australiens en Corse du sud

Une expérimentation a été menée en Corse du sud, de 1983 à 1986 afin de tester les capacités de croissance et production gommière d une vingtaine d espèces d Acacias australiens (1 500 individus environ). La moitié d entre elles ont produit de la gomme en plus ou moins grande quantité. Parmi les 7 espèces plus particulièrement retenues, l Acacia mearnsii s est révélé très remarquable par la qualité de sa gomme proche de celle du meilleur gommier saharien, Acacia senegal

Busulphan is active against neuroblastoma and medulloblastoma xenografts in athymic mice at clinically achievable plasma drug concentrations

High-dose busulphan-containing chemotherapy regimens have shown high response rates in children with relapsed or refractory neuroblastoma, Ewing's sarcoma and medulloblastoma. However, the anti-tumour activity of busulfan as a single agent remains to be defined, and this was evaluated in athymic mice bearing advanced stage subcutaneous paediatric solid tumour xenografts. Because busulphan is highly insoluble in water, the use of several vehicles for enteral and parenteral administration was first investigated in terms of pharmacokinetics and toxicity. The highest bioavailability was obtained with busulphan in DMSO administered i.p. When busulphan was suspended in carboxymethylcellulose and given orally or i.p., the bioavailability was poor. Then, in the therapeutic experiments, busulphan in DMSO was administered i.p. on days 0 and 4. At the maximum tolerated total dose (50 mg kg−1), busulphan induced a significant tumour growth delay, ranging from 12 to 34 days in the three neuroblastomas evaluated and in one out of three medulloblastomas. At a dose level above the maximum tolerated dose, busulphan induced complete and partial tumour regressions. Busulphan was inactive in a peripheral primitive neuroectodermal tumour (PNET) xenograft. When busulphan pharmacokinetics in mice and humans were considered, the estimated systemic exposure at the therapeutically active dose in mice (113 μg h ml−1) was close to the mean total systemic exposure in children receiving high-dose busulphan (102.4 μg h ml−1). In conclusion, busulphan displayed a significant anti-tumour activity in neuroblastoma and medulloblastoma xenografts at plasma drug concentrations which can be achieved clinically in children receiving high-dose busulphan-containing regimens. 1999 Cancer Research Campaig

Market access to new anticancer medicines for children and adolescents with cancer in Europe

BACKGROUND AND AIMS: There is an alarming delay in Europe for anticancer medicines becoming accessible for children. Following a paediatric European Union marketing authorisation, national Health Technology Assessment (HTA) agencies evaluate effectiveness, and safety of medicines to support decision on their cost and reimbursement. This study (a SIOPE Access to Medicines project) aimed to evaluate how these HTA evaluations take place for anticancer medicines indicated for paediatric use in Europe and to explore where the delays for market access originate. METHODS: We obtained HTA reports from the public domain for nine European countries for blinatumomab, dinutuximab beta and tisagenlecleucel. We evaluated the time elapsed between marketing authorisation for a paediatric indication and a national HTA decision and the nature of the decision. RESULTS: Out of 23 HTA decisions (four countries without blinatumomab report), 18 were positive, two with restrictions, three negative. For blinatumomab, tisagenlecleucel and dinutuximab beta, the median time to an HTA decision after regulatory approval for paediatric use was 353 days (range 193-751), 141 days (range 77-517) and 515 days (range 0-780), respectively, with variability between countries. Dinutuximab beta and tisagenlecleucel were first introduced in children, but did not result in shorter time to HTA decision. For blinatumomab, marketing authorisation followed 1008 days after the indication in adults, with HTA applications submitted a median of 167 days later, and a recommendation after 145 days. CONCLUSIONS: This study reveals ample variability in HTA decision making in nine European Union countries. Collaboration and alignment of required evidence is needed to facilitate robust scientific HTA assessments, also considering methodological challenges in paediatric oncology

Potential of sorghum and physic nut (Jatropha curcas) for management of plant bugs (Hemiptera: Miridae) and cotton bollworm (Helicoverpa armigera) on cotton in an assisted trap-cropping strategy

The cotton bollworm (CBW) Helicoverpa armigera and to a lesser extent plant bugs (PB) (Hemiptera: Miridae) are important pests of cotton in Africa. For sustainability reasons, it is necessary to reduce use of chemical control measures for these pests. A promising alternative to chemical control of both CBW and PB is trap cropping, assisted with botanical pesticides sprays, if needed. We report studies conducted from 1995–98 on sorghum attractiveness to PB and CBW, on the potential of physic nut (Jatropha curcas) extracts [particularly the phorbol ester (PE) fraction of the oil] for sorghum protection fromPB damage, and on the insecticidal activity of Jatropha extracts on CBW. At the ICRISAT research station (Samanko, Mali), infestation by the five main species of PB (accounting for 96% of total) was much higher on sorghum than on cotton. In the Kolokani region, CBW infestation was negligible on the Guinea loose-panicled sorghum cultivar Bibalawili, while it was significant on both compact-panicled PB susceptible ICSH 89002 and PB resistant Malisor 84-7. At Samanko, Jatropha oil application on sorghum panicles showed some effect on PB when damage level was high, better than Jatropha and neem aqueous extracts. However, it did not compete with pyrethroid protection level. PE contact toxicity on CBW larvae was too low to determine a LC 50. Aningestion insecticidal activity of PE was found on all tested larval instars. Contact toxicity LC 50 of PE on eggs was 1.66 g ml-1. Development of larvae and reproductive ability of adults derived from new-laid eggs treated with solutions of 0.35 g ml-1 PE and above were considerably affected. Prospects for using sorghum and Jatropha extracts for cotton protection against insect pests in an assisted trap-cropping strategy are discussed