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Biomedical subjects

B Robertson

Publications and source records attributed to B Robertson.

At least 361 records · Page 20Linked to original sources
PubMed1979

Transganglionic transport of horseradish peroxidase in primary sensory neurons.

The cut end of the sciatic nerve of adult rats was exposed to horseradish peroxidase (HRP). The rats were allowed to survive for 12 h--5 days. 12--18 h postoperatively small dorsal root ganglion cells more heavily labeled than large ones. After 48--72 h more large cells were intensely labeled. From 18 h onwards large amounts of HRP labeling was observed ipsilaterally in the superficial laminae of the dorsal horn, from 48 h also in deeper laminae and in the gracile nucleus. The heavy labeling clearly indicates the potential of the present approach for mapping purposes. The findings also indicate that short postoperative survivals can be used for rather selective marking of small cells and fibers.

Animals↗
PubMed1979

Isoxsuprine infusion to the pregnant rabbit and its effect on fetal lung surfactant.

Rabbit does, pregnant on the 28th day, were infused with isoxsuprine 2.5 mg/kg body weight/h in 50 ml 5% glucose, or with glucose only. The isoxsuprine caused maternal heart rate to increase and blood pressure, mean and diastolic, to decrease. The volume of fetal pulmonary fluid (FPF) and the wet lung weight/body weight ratio were significantly lowered by isoxsuprine. Lecithin/sphingomyelin ratio of FPF in isoxsuprine-infused animals was higher, compared with controls, not infused. Minimal surface tension of FPF, evaluated with pulsating bubble, was significantly lower in treated fetuses. Histologic examination of the fetal lungs after fixation with potassium dichromate and mercuric chloride showed that in isoxsuprine-treated litters FPF contained more granular and sudanophilic material. The results offer further evidence that isoxsuprine causes dehydration of fetal lungs and a release of pulmonary surfactant.

Animals↗
PubMed1978

Improved ventilation of prematurely delivered primates following tracheal deposition of surfactant.

Twelve rhesus monkeys were delivered prematurely at 129, 130, or 131 days. The first breath was inhibited while tracheotomy was performed and a catheter introduced into the umbilical artery. Into the tracheal tubes of six of the newborn monkeys was instilled 0.20 to 0.27 ml. of a natural surfactant (SA) suspension, obtained from lung wash of adult rabbits. Nothing was given to six control monkeys. Breathing was then supported with a ventilator. Although its settings were adjusted in attempts to maintain normal blood gases, the control monkeys developed severe hypercapnia and acidosis, and two died after 4 1/2 and 5 1/2 hours. The remaining four control monkeys and the six treated monkeys were killed after six hours. Pulmonary pressure-volume characteristics were conspicuously better following SA treatment. It was concluded that instillation of SA in the upper airways of premature primates prior to their first breath holds promise as an effective way of preventing respiratory distress.

Animals↗
PubMed1978

Hyaline membrane disease. Effect of surfactant prophylaxis on lung morphology in premature primates.

Neonatal lung morphology was evaluated in 12 rhesus monkeys delivered by caesarean section 1 month before term and cared for as human premature neonates. In 6 monkeys, 0.20 to 0.27 ml of natural rabbit surfactant (SA) was instilled intratracheally before the first breath; the other 6 served as controls. Histology and morphometry of the controls' lungs revealed changes typical of hyaline membrane disease (HMD) in human premature infants, whereas the SA-treated lungs showed improved alveolar expansion and only minor lesions typical of HMD. Transmission and scanning electron microscopy of the controls' lungs showed extensive necrosis and desquamation of bronchiolar epithelium, with formation of hyaline membranes; Type I alveolar epithelial cells showed lesions similar to those in bronchioles, but immature Type II cells appeared relatively well preserved. In the lungs of SA-treated animals, the epithelial lining of most airways and alveoli was intact. This first demonstration of the beneficial effect of exogenous SA on lung adaptation in premature primates indicates that prophylaxis with SA might prevent HMD in premature human infants.

Animals↗
PubMed1977

Isoxsuprine-induced release of pulmonary surfactant in the rabbit fetus.

Rabbit fetuses were injected intramuscularly with 0.5 mg. of isoxsuprine on the twenty-eighth day of gestation. They were killed in utero four hours after the injection, and fetal pulmonary fluid (FPF) was collected through a tracheal catheter. The quantity of FPF and the lung weight/body weight ratio were both significantly less in the isoxsuprine-treated fetuses than in control fetuses. Surface activity, evaluated with pulsating bubble, and the lecithin/sphingomyelin (L/S) ratio were greater in FPF from isoxsuprine-treated animals than in control samples. We concluded that isoxsuprine is able to dehydrate the fetal lung and cause a release of surfactant stored in type II pneumocytes. This latter conclusion was supported by a significant decrease in the number of lamellar inclusions observed in these cells.

Amniotic Fluid↗
PubMed1976

The alveolar lining layer in experimental paraquat poisoning.

Rats were injected with paraquat, 35 mg/kg, and killed 8 or 12 hours later. Electron microscopic studies of the lungs revealed degenerative changes in alveolar epithelium and alveolar capillary endothelium after 8 hours. After 12 hours, the alveolar lining layer was contaminated with cellular debris from disintegrating alveolar epithelium. This contamination is probably responsible for the inactivation of lung surfactant that can be demonstrated in early stages of experimental paraquat poisoning.

Animals↗
PubMed1976

Liquid ventilation in immature newborn rabbits.

Rabbit fetuses delivered 3 days before term were artificially ventilated with air, oxygen, or oxygenated liquid fluorocarbon for 1.5-3 h. Oxygenation, as revealed by skin colour and ECG was superior in liquid-ventilated animals. Also, liquid ventilation was less harmful to the bronchiolar epithelium and, in contrast to ventilation with gas or oxygen, did not cause the formation of hyaline membranes.

Animals↗
PubMed1976

Densitometric evaluation of lung aeration in chest films.

Lung aeration can be evaluated densitometrically from chest films, using a microscope with one eyepiece replaced by a photocell, and the attenuation of the pulmonary parenchyma can be assessed numberically, as a "radiologic expansion index". In premature rabbit neonates, this index was significantly increased among animals receiving a pharyngeal deposit of homologous lung surfactant before the first breath, as compared with untreated controls. This technique could in modified form be used for clinical purposes, such as the evaluation of lung aeration in newborn infants with respiratory distress.

Absorptiometry, Photon↗
PubMed1976

BCG osteomyelitis: experience in the Stockholm region over the years 1961-1974.

Eighteen cases of bone and joint tuberculosis in children were diagnosed in the Stockholm region (about 1,500,000 population) over the period 1961-1974. BCG infection was verified by culture and identification of bacterial type in seven, all after 1968. The same origin can be presumed in most of the remaining eleven cases, in spite of the absence of bacterial verification. The increased frequency of complications after BCG vaccination may necessitate a revision of the vaccination programme. We recommend operative treatment, which has not led to any growth disturbances or impairment of joint function, although the lesions were invariably localised close to growth zones and joints.

BCG Vaccine↗
PubMed1976

Surface forces in respiratory bronchioles during a first breath-model experiment and some theoretical considerations.

In a physical sense the terminal bronchioles are capillaries, and the air-liquid interface descending through them during the first breath will therefore have a spherical curvature with a radius identical to that of the airway. Air will reach the alveolus if the liquid-coated bronchiolar wall proximal to the air-liquid interface can withstand the pressure gradient required to push the interface towards the periphery. Otherwise, there is a risk that the bronchioles become overexpanded while the alveoli remain non-aerated.

Bronchi↗
PubMed1975

Radiologic evaluation of the premature newborn rabbit after pharyngeal deposition of surfactant.

Premature rabbit fetuses were delivered by hysterotomy and, prior to the first breath, a concentrated homologous surfactant suspension was deposited in the pharynx. With repeated radiograms, the effect of this treatment was studied during the first two hours of extrauterine life. The lung aeration was quantitated with densitometry, and the chest expansion was assessed by measuring the inferior angle formed by the fourth ribs. In comparison with control animals, the treated animals demonstrated a greater chest expansion, and their lungs were significantly better aerated. Clinical application has to await further studies.

Absorptiometry, Photon↗
PubMed1975

Mechanism of plasminogen activator and factor VIII increase after vasoactive drugs.

Adrenaline, nicotinic acid (NA), vasopressin (LVP) and other drugs affecting vascular motility are known to increase plasminogen activator (PA) and factor-VIII plasma levels in man. To evaluate the hypothesis that NA, LVP and adrenaline release PA from the endothelial cells of the vessel wall through their common effect on vascular motility, PA has been characterized by means of a histochemical technique on vein biopsies obtained from human volunteers after infusion of the compounds. Furthermore, the effect of single and repeated administration has been compared in order to investigate whether the pattern of PA and factor-VIII variations in plasma is similar with the three drugs. There was no major difference in the PA content of the veins following the marked and sustained increase of the corresponding plasma activities. A simple explanation is that the intensity and duration of the stimulus may not be sufficient to deplete the large stores of the vessel walls. The magnitude, time course and duration of the plasmatic response after single and repeated infusions was on the whole different and peculiar for each drug. A derivative of LVP which is free of vasoactive actions was more effective than LVP in inducing the responses, which could also be elicited in two anephric subjects. These findings suggest that vasoactivity is unlikely to provide the clue to a common pathway for the fibrinolysis and coagulation response after the compounds, and support the existence of different specific receptors.

Adult↗
PubMed1975

Lung expansion and the formation of the alveolar lining layer in the fullterm newborn rabbit.

Light and electron microscopic studies of lungs from fullterm newborn rabbits, 0-24 hours after birth, revealed a patchy alveolar air expansion during the first few hours of extra-uterine life. Fairly uniform aeration of alveoli was noted 6-24 hours after birth but minor "unexpanded" areas were still present after 24 hours. In the fetal pulmonary fluid as well as in the alveolar lining layer formed after the onset of breathing there are multiple large phospholipid complexes, and a discontinuous multilamellar surface film can be demonstrated in some alveoli from 2 hours after birth. Apparently, the neonatal adaptation of the rabbit lung is a protracted process, not even complete at the age of 24 hours.

Adaptation, Physiological↗