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The objective of the study was to determine whether administering doxapram by infusion to the very low birthweight infant, prior to extubation during the first 3 weeks of life, would increase the incidence of successful extubation. The study patients, 56 infants of less than 1251 g birthweight and less than 30 weeks' gestation, were entered in the first 3 weeks of life when lung disease had started to improve. A randomized blinded trial was performed, with infants receiving 3.5 mg kg−1 doxapram bolus, followed by an infusion at 1 mg kg−1 h−1 , or placebo. Weaning from positive pressure ventilation was standardized and extubation occurred after a 12 h trial of an intermittent mandatory ventilation (IMV) rate of 6 breaths min−1 , if PCO2 < 55 mmHg, pH > 7.26, and FiO2 < 0.45. Study drug was continued for 48 h postextubation, and the infants were placed on nasopharyngeal continuous positive airway pressure (CPAP) for 72 h postextubation. Extubation failure within the first 72 h after extubation was objectively defined in terms of acidosis (pH < 7.26), hypercarbia (PCO2 > 55 mmHg), excessive oxygen requirement (FiO2 > 0.8) or frequent apnoea (more than three in 12 h, or more than two requiring face mask IMV in 24 h). No difference was noted in the frequency of successful extubation between the groups. Fifteen infants in each group were successfully extubated before the 10th day of the study. In conclusion, when given in accordance with this protocol doxapram does not increase the likelihood of successful extubation in the very low birthweight infant. Increasing successful extubations in this group of infants will require other strategies. 相似文献
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Cytotoxic T lymphocytes (CTL) have been implicated in immunity to
Plasmodium falciparum infection and disease. We have previously described
the use of peptides to define malaria-specific CTL epitopes. To determine
whether these peptide epitopes are processed intracellularly from the whole
antigen we have developed recombinant vaccinia viruses (rVV) expressing
three malaria antigens: thrombospondin-related adhesive protein (TRAP),
Pfs16 and the C- terminal half of liver-stage antigen (LSA)-1. Target cells
infected with recombinant viruses were lysed by malaria-specific CTL from
semi- immune African donors. We also tested the ability of cells infected
with these recombinant vaccinia viruses to re-stimulate malaria- specific
CTL in peripheral blood lymphocytes from malaria immune adults. Two other
pox virus recombinants, NYVAC, an attenuated vaccinia virus, and ALVAC, a
canarypox virus, both expressing malaria antigens were also evaluated for
their ability to stimulate malaria-specific CTL in contrast to peptide,
none of these viruses successfully re- stimulated CTL from the peripheral
blood lymphocytes of semi-immune donors. The ability of human CTL from
naturally exposed individuals to recognize processed antigen supports the
relevance of these cells in protective immunity to malaria.
相似文献
148.
In healthy subjects, standing elicits a reduction in blood flow to the skin of the foot. In adults with insulin dependent diabetes this posturally induced response is deficient, resulting in capillary hypertension when the foot is in the dependent position (that is, below heart level). Such functional abnormalities of the microcirculation in diabetes may precede any evidence of clinically detectable microangiopathy. This study investigates the posturally induced change in blood flow to the skin of the foot in prepubertal and postpubertal patients with insulin dependent diabetes. Laser Doppler fluximetry was used to assess the postural change in blood flow at the pulp of the great toe. Postural vasoconstriction (dependent flux value/supine flux value x 100) was greater after puberty in normal subjects (median (range) 60.4 (7.0-164.9)% prepubertal v 20.5 (5.9-101.0)% postpubertal). Prepubertal children with diabetes did not differ from their healthy peers (69.8 (7.2-192.7)% with diabetes v 60.4 (7.0-164.9)% controls); however postpubertal children with diabetes had a significantly impaired postural vasoconstriction (40.6 (7.9-140.2)% with diabetes v 20.5 (5.9-101.7)% controls). Abnormalities in the normal reduction of blood flow on standing occurred in young postpubertal children with diabetes, most of whom were free of complications. 相似文献
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