Low energy proton irradiation effects on alveolar macrophages from young and aged rats

A prospective study was undertaken to assess the radiotoxicity of accelerated particles in pulmonary alveolar macrophages (AM). We evaluated the effects of a single dose (10-75 Gy) of an external low-energy (20 MeV) proton beam on cultured AM oxidative metabolism and phagocytic function. Macrophages are the first line of defense against invading pathogens and are known to generate superoxide anion (O2), nitric oxide (NO), and mediators of antimicrobial and antitumoral defense mechanisms. We obtained AM by bronchoalveolar lavage from young (1-2 month old) and aged (9-12 month old) male Wistar rats. Cell viability, phagocytosis, O2 and NO production in control and proton-irradiated cultured AM were evaluated The effect of proton irradiation on cell viability was dose-dependent The higher doses induced a dramatic decrease in viability in the aged population. Phagocytosis increased 1.3-1.4 fold inboth populations irrespective of the dose delivered. Generation of O2 was always higher in the aged population for all the doses assayed and showed no significant variation from the control values. In the young population a clear increase was observed with doses of 25 and 50 Gy. NO production in AM from young animals rose in a dose-dependent manner. Conversely, proton irradiation did not affect NO production in macrophages from aged animals. The results of this study demonstrate that AM isolated from young and aged rats are functionally different and show a distinct behavior when exposed to proton irradiation. These findings suggest that age may condition response and must be taken into account when accelerated particle-radiotherapy protocols are considered as a valid therapeutic option for the treatment of cancer. To the best of our knowledge, this is the first report comparing sham-irradiated and proton-irradiated young and aged AM.

In vivo response to the different LET regions of a 55 MeV helium ion beam

We evaluated the in vivo response to heavy particle irradiation in rat tail epidermis using silver-stained nucleolar organizer regions (AgNOR) as the end-point. The energy degradation of the beam across the circular section of the tail allowed us to study the damage elicited by two different LET regions of a helium beam, i.e. non-Bragg peak (NBP) and Bragg peak (BP), at different sites on the same sample. The tails were locally irradiated with a helium ion beam at different fluences. AgNOR exhibited marked variations between tissue areas only a few micrometers apart within each tail exposed to a given beam fluence. An analysis of the AgNOR variations in NBP and BP areas of tails exposed to different beam fluences revealed a dose-dependent effect. The AgNOR provide quantitative evidence of differential damage in neighboring tissue areas exposed to different LET regions of a helium-ion beam.

[Preliminary study of the safety and immunogenicity of the attenuated VD47/25 strain of camelpoxvirus]

The safety and immunogenicity of the attenuated VD47/25 strain of camelpoxvirus were tested on 30 camel calves in Mauritania. Post-inoculation clinical symptoms were absent during the 40 days of observation. Serum samples collected during this period showed low levels of neutralizing antibodies (1/4-1/16). In vivo titration of a virulent strain of camelpoxvirus in vaccinated camels and control animals enabled the calculation of the PD50 (50% protective dose) which contained the equivalent of 10(3.7) TCID50 (50% cell culture infective dose). Other studies are still required to determine the dose of this vaccine needed to protect 95% of vaccinated animals.

The influence of high dietary protein, energy and mineral intake on deficient young camel (Camelus dromedarius)--I. Changes in metabolic profiles and growth performance

1. The main forage for camels in northern Djibouti (mangrove with Avicennia marina) is very poor in nitrogen and energy. In a trial, 32 young camels (less than 2 years old) were used in four groups of eight each. 2. All the camels received mangrove as basal diet ad lib. 3. After 1 month, the camels received mineral supplementation in copper and zinc (groups 1 and 3) or/and a concentrate rich in protein and energy (groups 2 and 3) or continued with the basal diet (controls). 4. Any supplementation was stopped after 2 months for 1 month. 5. Growth performance was 550 g/day (concentrate-supplemented camels) and 570 g/day (concentrate+mineral-supplemented camels). 6. The growth was negative for the two others groups (-260 g/day). 7. Food intake of mangrove was slightly more important with mineral supplementation only and with mineral+concentrate supplementation. 8. The changes in metabolic profiles have shown an important catabolism in non-supplemented animals, an increase of urea and free fatty acid concentrations in plasma and a decrease of glucose concentrations. 9. Three camels died in the control group with symptoms of starvation and signs of liver damage (increase of liver enzymes glutamate dehydrogenase and gamma-glutamyl transferase).

The influence of high dietary protein, energy and mineral intake on deficient young camel (Camelus dromedarius)—II. Changes in mineral status

1. Mangrove Avicennia marina is poor in some trace elements such as copper, zinc and manganese. In a trial we used 32 young camels divided into four groups. 2. Groups 1 and 3 were supplemented with copper and zinc in drinking water after 1 month of mangrove feeding. 3. Groups 2 and 3 received concentrate rich in protein and energy. The supplementation was stopped after 2 months. 4. All the camels were deficient in trace elements at the beginning of mineral supplementation. 5. The plasma concentration of copper increased significantly up to normal levels (less than 70 micrograms/100 ml) in energy protein supplemented groups, but the quantity supplied (100 mg of copper sulphate/day) was not sufficient to maintain this level after the end of supplementation. 6. The original zinc deficiency was too severe to observe a significant effect of the mineral supplementation. 7. Calcium, magnesium and phosphorus levels were improved during the supplementation period in protein-energy supplemented groups. 8. A high interaction between mineral absorption and quality of the diet was observed. A well-balanced diet seems essential to avoid deficient mineral status.