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Biomedical subjects

B Lachmann

Publications and source records attributed to B Lachmann.

At least 127 records · Page 7Linked to original sources
PubMed1991

Effect of surfactant replacement on Pneumocystis carinii pneumonia in rats.

The effect of intratracheal surfactant instillation on pulmonary function in rats with Pneumocystis carinii pneumonia (PCP) was investigated. In those animals which developed PCP with severe respiratory failure after administration of cortisone acetate s.c. over 8-12 weeks, pulmonary function was improved by surfactant instillation. PaO2 values 30 min after surfactant instillation were significantly higher compared to pretreatment values and also compared to PaO2 values of rats 30 min after receiving saline (482.9 mmHg +/- 44.7, 170.7 mmHg +/- 39.3 and 67.2 mmHg +/- 17.4, respectively). Histological examination showed that alveoli of rats with PCP which received no exogenous surfactant are filled with foamy edema, whereas after exogenous surfactant alveoli are stabilized and well-aerated. These results indicate that exogenous surfactant may help patients with severe PCP to overcome an acute stage of respiratory distress.

Animals↗
PubMed1991

Protection against influenza A virus infection in mice by oral immunization with a polyvalent bacterial lysate.

A study is presented which investigated whether oral immunization with a polyvalent bacterial lysate (Paspat oral) can sufficiently enhance cell-mediated defense mechanisms to protect mice against influenza A virus infection. It was found that oral immunization reduced mortality due to influenza A infection with 15-70%, depending on the quantity of virus administered and and the moment of infection. Cyclosporin A severely reduced the protective effect of oral immunization, suggesting that a major effect of oral immunization in these studies is T-cell activation. The effect of oral immunization on macrophageal activity was evaluated by measuring cyclic-AMP in alveolar macrophages (AMs) obtained by bronchoalveolar lavage. Before infection, basal activity levels of AMs in immunized mice were significantly lower than in controls. Five days after infection, however, basal activity level of AMs in immunized mice was significantly higher than AM activity in controls. Stimulation of AMs with PGE2 significantly reduced cellular activity in both groups, before and after infection. However, cellular activity of AMs from immunized animals was less reduced than cellular activity of control macrophages. Activity of AMs of immunized animals was significantly more reduced by histamine than activity of control macrophages. It is concluded that oral immunization with Paspat oral stimulates T-cell-dependent immune mechanisms, resulting in protection against influenza A virus infection in mice.

Administration, Oral↗
PubMed1991

Effects of antisurfactant antibodies on the course of mild respiratory distress syndrome.

The role of surfactant-associated proteins in surfactant function was studied by selectively blocking these proteins with monoclonal antibodies. Four monoclonal antibodies, M1, M2, M3, and M4 were identified and their reactivities examined by Western blot analysis. M1, M2, and M4 bind, respectively, 8-, 10- and both 10- and 34-kD proteins. M3 antibody did not recognize a protein as assayed by this technique. These antibodies were then administered intratracheally to adult rats that had been partially depleted of lung surfactant by broncholavage. None of these antibodies had any deleterious effect on pulmonary function. On the other hand, M4 antibody significantly improved gas exchange. Possible mechanisms by which antibody may effect such improvement are discussed.

Animals↗
PubMed1991

In vivo and in vitro inactivation of bovine surfactant by an anti-surfactant monoclonal antibody.

In this study the importance of a low-weight surfactant protein (11 kDa) is demonstrated by selectively blocking this protein with a monoclonal antibody. In adult rats respiratory failure was induced by repeated bronchoalveolar lavage to remove all pulmonary surfactant. It was shown that surfactant mixed with the antibody was not capable of restoring lung function when compared with surfactant alone or surfactant mixed with control serum. Using the pulsating bubble surfactometer, it could be demonstrated that surfactant mixed with this antibody had a significant higher minimum surface tension when compared with surfactant alone, or surfactant mixed with an unrelated mouse immunoglobulin G (IgG). The inhibition of surfactant function by the monoclonal antibody suggests the importance of the 11 kDa protein for normal surfactant function.

Animals↗
PubMed1991

Induction of a mucosal immune response by oral immunization. An overview.

The function of secretory antibodies is to prevent or limit the entrance of pathogens into the internal milieu of the body. The mucosal immune system may be stimulated by orally applied immunomodulators. Oral immunization circumvents the stringent criteria for injectable vaccines and large populations can be immunized simultaneously. Oral immunization may improve the chances in eliminating severe respiratory diseases, venereal diseases and infectious diarrhoea. In this overview the results of 144 international publications are discussed critically.

Administration, Oral↗
PubMed1991

Intratracheal surfactant administration restores gas exchange in experimental adult respiratory distress syndrome associated with viral pneumonia.

The effect of intratracheal surfactant administration was studied in rats with adult respiratory distress syndrome associated with infection with nebulized Sendai virus. Thirty-six hours after infection, animals (n = 7) showed severely impaired gas exchange and acidosis during artificial ventilation (PaO2 = 152.2 +/- 18.7, PaCO2 = 65.3 +/- 19.2, pH = 7.26 +/- 0.11) with a pressure-controlled mode, standard frequency of 35/min, peak airway pressure of 15 cm H2O (15/0), inspiratory/expiratory ratio of 1:2, and F1O2 = 1. Gas exchange improved (P = 0.02) with increased ventilator pressures with PEEP (25/4). Forty-eight hours after infection, blood gas tensions could no longer be significantly improved by these same ventilator settings (PaO2 = 123.8 +/- 31.0, PaCO2 = 95.1 +/- 43.6, pH = 7.12 +/- 0.16, n = 9). At this time, surfactant replacement dramatically increased arterial oxygenation within 5 min (PaO2 = 389.4 +/- 79.9) and resulted in a fourfold increase in PaO2 within 2 h. It is concluded that intratracheal surfactant administration is a promising approach in the treatment of respiratory failure during adult respiratory distress syndrome associated with viral pneumonia.

Animals↗
PubMed1990

Safety and efficacy of xenon in routine use as an inhalational anaesthetic.

40 patients (24 male, 16 female, aged 21-59 years) of American Society of Anesthesiologists class I or II who were undergoing routine surgery took part in a randomised, double-blind comparison of the anaesthetic efficacy and potency of xenon and nitrous oxide and their effects on the circulatory and respiratory systems. During anaesthesia, for each rise in blood pressure of more than 20% of the preanaesthetic (baseline) value, the patient received 0.1 mg fentanyl. The total amount of fentanyl required per patient was used as an index of the anaesthetic potency of the study gases. Patients in the xenon group required on average only 0.05 mg fentanyl, whereas those in the nitrous oxide group required 0.24 mg fentanyl; the duration of anaesthesia was similar in the two groups. Changes in blood pressure were significantly greater throughout the study in the nitrous oxide than in the xenon group. Thorax-lung compliance fell during the study period in the nitrous oxide group but not in the xenon group. Thus, xenon is a potent and effective anaesthetic which can be safely used under routine conditions.

Adult↗
PubMed1990

Online measurements of SaO2, Ht and Hb using a micro transmission cell.

Recently a Micro Transmission Cell has been developed based on spectrophotometry for in vivo monitoring of SaO2 together with Hb. A study in pigs was performed to compare the cell with standard methods for measuring SaO2, Hb and Ht. The results show that the cell is capable of following the trends of SaO2, Hb and Ht at different Hb concentrations and/or O2 saturations.

Animals↗
PubMed1990

Experimentally induced congenital diaphragmatic hernia in rats.

Experiments to induce congenital diaphragmatic hernia (CDH) in rats, by means of administering a single dose of 2,4-dichlorophenyl-P-nitrophenyl (Nitrofen) on the 10th day of gestation, are reported here. Previously, congenital diaphragmatic hernia has been induced in sheep late in fetal development, and in mice early in gestation. The rat model, including a control group, was used to evaluate lung development and the presence of lung hypoplasia by morphometrical analysis. It was found that the single dose of Nitrofen, given 5 days before the normal closure of the diaphragm in the rat, leads to a high incidence of diaphragmatic hernia, mainly on the right side, and highly abnormal lung development (hypoplasia) comparable to the human situation. Both the lung weight/body weight index as well as the radial alveolar count were significantly lower in animals with CDH (P less than .05). This animal model offers a good opportunity to study abnormal lung development in relation to ventilatory capacity and pulmonary vascular reactivity.

Animals↗
PubMed1990

Haemodynamic and neurohumoral effects of xenon anaesthesia. A comparison with nitrous oxide.

Thirty-two patients were randomly allocated to be anaesthetised either with nitrous oxide or xenon. Those who received nitrous oxide required significantly more fentanyl peroperatively. Arterial blood pressure and heart rate were adequately controlled during surgery in both groups. Plasma noradrenaline and prolactin increased peroperatively in both groups, but plasma adrenaline and cortisol, which increased in the nitrous oxide group, did not change in the xenon group. Growth hormone was below control in those given xenon, but not in the nitrous oxide group, while dopamine remained unchanged in both groups. Postoperative plasma concentrations of noradrenaline, adrenaline, cortisol and prolactin (in both groups) and dopamine (in the nitrous oxide group) were elevated, and slowly returned to control. No differences were seen between the two gases in effects on plasma sodium and potassium. Xenon, because of its favourable haemodynamic, neurohumoral and antinociceptive properties, deserves a more prominent place in anaesthetic practice than it has so far occupied.

Adult↗
PubMed1990

Pulmonary clearance of 99mTc-DTPA during halothane anaesthesia.

We studied the integrity of the alveolo-capillary barrier during different forms of anaesthesia by measuring the pulmonary clearance of inhaled 99mTc-DTPA. We studied four groups of rabbits. Groups I and II were anaesthetized with nembuthal only and the fractional concentration of inspired oxygen (F1O2) was 0.30 and 1.00, respectively. Groups III and IV were anaesthetized with 1% halothane and F1O2 was 0.30 and 0.99, respectively. 99mTc-DTPA was administered as a fine aerosol and the clearance of the tracer from the lungs was subsequently measured with a gamma camera. The mean half-life of the tracer in the lungs in Groups I-IV was 60, 58, 59 and 26 min, respectively. The rapid pulmonary clearance of 99mTc-DTPA in Group IV indicates that halothane in combination with high oxygen concentration increases the permeability of the alveolo-capillary barrier. This may be due to effects on the pulmonary surfactant system and/or the alveolar epithelium.

Anesthesia, Inhalation↗
PubMed1990

Oral immunization with bacterial lysate against infection with Streptococcus pneumoniae in mice.

The protective effect of oral immunization against infection with Streptococcus pneumoniae was investigated in mice. Two bacterial lysates, one with an additional lysate of Candida albicans, were investigated. Intranasal inoculation of adult Balb-C mice with a S. pneumoniae type I strain resulted in a lethal infection, with deaths occurring from the 2nd until the 6th day after infection. Oral immunization resulted in a significant decrease in mortality rate (18-48% reduction). No significant difference in mortality rates was observed between the groups immunized with different lysates in the same concentrations.

Adjuvants, Immunologic↗