Effects of cigarette smoke and hypoxia on pulmonary circulation in the guinea pig

Cigarette smoke (CS) and chronic hypoxia (CH) can produce pulmonary hypertension. Similarities and differences between both exposures and their interaction have not been explored. The aim of the present study was to investigate the effects of CS and CH, as single factors or in combination, on the pulmonary circulation in the guinea pig. 51 guinea pigs were exposed to CS for 12 weeks and 32 were sham-exposed. 50% of the animals in each group were additionally exposed to CH for the final 2 weeks. We measured pulmonary artery pressure (P(pa)), and the weight ratio between the right ventricle (RV) and left ventricle plus the septum. Pulmonary artery contractility in response to noradrenaline (NA), endothelium-dependent vasodilatation and distensibility were evaluated in organ bath chambers. The number of small intrapulmonary vessels showing immunoreactivity to smooth muscle (SM) α-actin and double elastic laminas was assessed microscopically. CS and CH induced similar increases of P(pa) and RV hypertrophy (p<0.05 for both), effects that were further enhanced when both factors were combined. CH increased the contractility to NA (p<0.01) and reduced the distensibility (p<0.05) of pulmonary arteries. Animals exposed to CS showed an increased number of small vessels with positive immunoreactivity to SM α-actin (p<0.01) and those exposed to CH a greater proportion of vessels with double elastic laminas (p<0.05). We conclude that CH amplifies the detrimental effects of CS on the pulmonary circulation by altering the mechanical properties of pulmonary arteries and enhancing the remodelling of pulmonary arterioles.

[Long-term survival in childhood acute lymphocitic leukemia (author's transl)]

Long-term results in the treatment of 116 patients of acute lymphocitic leukemia with ages between six months and seven years are reported. A first group A, formed by 76 patients, was treated with prednisone and vincristine as induction protocol and maintenance therapy with 6-mercaptopurine or methotrexate. No neuromeningeal prophylaxis was made, except some cases in which intratecal methotrexate was applied. 27 patients are alive, 21 of them (27,6%) remain in complete remission for more than three years. A second group B, formed by 40 patients, was treated more recently; with an induction protocol composed by prednisone, vincristine and L-asparaginase. All patients in this group received cranial irradiation and intratecal methotrexate. 31 patients are alive (77,5%), 13 of them (32,5%) remain in complete remission for more than two years. The evolution period in this group B is shorter, but some features are exposed which suggest the possibility of long-term better results.