The response of foetal sheep and lambs to pulmonary inflation

Predicting non-relapse mortality following allogeneic hematopoietic cell transplantation during first remission of acute myeloid leukemia

The aim of this study was to develop a comprehensive system for predicting non-relapse mortality after allogeneic hematopoietic cell transplantation (HCT) during first complete remission (CR) of acute myeloid leukemia (AML). After dividing 2344 eligible patients randomly into a training set and a validation set, we first identified and scored five parameters, that is, age, sex, performance status, HCT-comorbidity index (HCT-CI), and donor type, on the basis of their impact on non-relapse mortality for patients in the training set. The non-relapse mortality-J (NRM-J) index using the sum of these scores was then applied to patients in the validation set, resulting in a clear differentiation of non-relapse mortality, with expected 2-year rates of 11%, 16%, 27%, and 33%, respectively (P < 0.001). The estimated c-statistic was 0.67, which was significantly higher than that of the European Society for Blood and Marrow Transplantation score (0.60, P = 0.002) and the HCT-CI (0.57, P < 0.001). The NRM-J index showed a significant association with overall survival, but not with relapse. Our findings demonstrate that the NRM-J index is useful for predicting post-transplant non-relapse mortality for patients with AML in first CR, for whom the decision of whether to perform allogeneic HCT is critical.

Postnatal development of the lung following denervation

We asked to what extent pulmonary innervation influences the postnatal development of the lung. To this end we performed cervical vagotomy and sympathectomy either on the right or on the left side in young rats and rabbits and rats after weaning. One to four weeks later we examined the lungs of the denervated side, the contralateral intact side of the same animal, and sham-operated controls. Dry lung weight, lung volume and the size of subpleural alveoli were not different among the three groups. Lung mechanical properties (static and dynamic lung compliances, lung resistance, frequency dependence of compliance), measured in rabbits, were also not different among groups of lungs, suggesting that neither central nor peripheral airways were markedly affected by the denervation. The breathing pattern, measured in the rats after weaning, was characterized by a larger tidal volume in the denervated animals than in controls, as expected after the partial pulmonary afferent denervation. The absence of major structural and functional changes in the lungs of these animals suggests that an increase in the mechanical stretch to the lung above that normally occurring during resting breathing does not influence the lung structure. We conclude that pulmonary innervation does not play an important role in the postnatal development of the lung.

Types of afferent nervous activity which may be measured in the vagus nerve of the sheep foetus

1. Afferent activity was measured in the vagus nerves in sixteen foetuses within 2-3 days of natural term and in two foetuses 130 and 135 days gestational age, exteriorized by hysterotomy from seventeen ewes given either a spinal anaesthetic (ten) or pentobarbitone sodium (seven).2. Activity from aortic chemoreceptors was observed which increased in rate with foetal hypoxia, NaCN or nicotine and temporary occlusion of the umbilical cord or veins. Activity was abolished or reduced with saline equilibrated with air.3. Activity from baroreceptors was observed which was synchronous with the arterial pulse and which followed changes in arterial pressure.4. Activity designated as arising from stretch receptors in the lungs or lower airways was observed which consisted of a regular discharge at 15-45 impulses sec(-1), which varied with intra-tracheal pressure, which increased with negative intrathoracic pressure generated by spontaneous respiratory movements, which, when the umbilical cord was occluded, at first increased in rate and then fell to zero at or about the occasion of the first breath. After breathing had been established, activity assumed the rhythmical pattern and showed evidence of slow adaptation of receptors seen in the adult. This activity was frequently modulated by the heart beat and after breathing had started it was reduced when carbon dioxide was raised.5. Respiratory movements with a frequency of 10-20/min occurred spontaneously in foetuses from ewes given a spinal anaesthetic and were associated with a modulation of the stretch receptor discharge. They could be induced by withdrawing fluid from the trachea and so lowering both intra-tracheal pressure and receptor discharge and were abolished by raising intra-tracheal pressure. These changes were abolished by sectioning the vagi just caudal to the nodose ganglion.6. These results indicate that there are excitatory and inhibitory pathways in the vagus nerves which are active in the foetus and which may well be concerned with the limitation of respiratory movements of the foetus and the onset of maintained respiration at birth.