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Biomedical subjects

P Lasch

Publications and source records attributed to P Lasch.

27 records · Page 2Linked to original sources

Indication for using extracorporeal membrane oxygenation in congenital diaphragmatic hernias and pulmonary hypoplasia.

Despite the apparent surgical simplicity of the anatomic defect, congenital diaphragmatic hernia continues to be a critical problem in neonatal surgery, so that survival is still uncertain. Therefore, we must realize that the barriers to survival are pulmonary parenchymal and vascular hypoplasia as well as the complex syndrome of persisting fetal circulation. However, new treatment methods, such as extracorporeal membrane oxygenation (ECMO), although controversial, may improve survival. We believe that no infant should be excluded from diaphragmatic repair or consideration for ECMO-support before accurate predictive parameters have been developed that take both pulmonary hypoplasia and pulmonary hypertension into account. ECMO additionally enables us to postpone the operation until stabilization of the newborn (Late Operation Protocol). Apart from this, we can probably improve the long-term results after ECMO by reconstructing the common carotid artery.

Combined Modality Therapy↗

[Course of chronic life-threatening digitalis poisoning in infancy with immunopharmacologic treatment using antidigoxin Fab of sheep].

A 2 months old girl was given a tenfold increased dosage of Beta-Methyldigoxin for 2 weeks and subsequently developed severe symptoms of glycoside intoxication. In hospital she was treated by digoxin-specific Fab antibody fragments. 18 hours later the symptoms had totally disappeared. However, 48 hours from the beginning of the treatment free digoxin levels rose again to toxic ranges. In chronic intoxications the rediffusion of glycosides from tissues and interstitial space seems to be much more pronounced than in acute intoxications, and there is a higher risk of reintoxication.

Chronic Disease↗

[Clinical application of extracorporeal membrane oxygenation (ECMO) in neonatal respiratory failure].

ECMO is a therapeutic alternative for newborns with respiratory insufficiency unmanageable by artificial ventilation. A modified heart-lung machine well suited for long-term application is used both to support life and to take over organ function, allowing this organ to rest and to recover. The ECMO-technique as practised in our group is equivalent to the venous-arterial bypass initiated by the Bartlett-team. Venous blood is drained from the right atrium via the right internal jugular vein. After passage through a membrane oxygenator and a heat exchanger it is returned in an arterialized state to the ascending aorta via the right carotid artery. Cannulation is followed by systemic heparinization. With a roller pump extracorporeal circulation is installed for 3-6 days with flow-rates of 80-120 ml/kg/min. The operation is performed under local anesthesia in the neonatal intensive care unit. The typical course of ECMO is stabilization for the first 24-48 hours on high bypass flow rates keeping paO2 at 50-60 mmHg with minimal ventilator settings (Pmax 20 mmHg. FiO2 0.3-0.4). Bypass flow rates can be reduced for the next 24 h and the patient is taken off and decanulated while on similar ventilator settings. Because of systemic heparinization intracranial bleeding is the main complication for a newborn child on ECMO. The incidence is about 10%. Premature infants per se have a high risk of major intracranial bleeding without ECMO. Therefore contraindications are infants under 35-weeks gestation, and a hemorrhage diagnosed by ultrasound prior to ECMO. Prediction of mortality is estimated by the alveoloarterial oxygen gradient (D [Aa] O2).(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Hemorrhage↗

[Extracorporeal membrane oxygenation (ECMO). A treatment alternative for newborn infants with severe respiratory disorder].

Extracorporeal Membrane Oxygenation (ECMO) is a promising alternative for newborns with critical respiratory disease, where conservative management is no longer sufficient. - Indications for ECMO include mainly the diagnoses Persisting Pulmonary Hypertension (PPHN), Meconium-Aspiration and Congenital Diaphragmatic Hernia. In patients with a mortality-prognosis of 80-100% ECMO will raise survival rates to about 80% with a good general developmental prognosis. Conditions, trainee programs, and experiences up to the first clinical application of ECMO are reported.

Diseases in Twins↗

Uncoupling of alpha-adrenoceptor-mediated inhibition of human platelet adenylate cyclase by N-ethylmaleimide.

Human platelet adenylate cyclase is stimulated by prostaglandin E1 (PGE1) and is inhibited by epinephrine via alpha-adrenoceptors. Both agonists, epinephrine more than PGE1, increase the activity of a low Km GTPase in platelet membranes. Pretreatment of intact platelets or platelet membranes with the sulfhydryl reagent, N-ethylmaleimide (NEM), abolished the inhibition of the adenylate cyclase and the concomitant stimulation of the GTPase by epinephrine. In contrast, stimulation of the adenylate cyclase by PGE1 was not affected or even increased by NEM pretreatment; only at high NEM concentrations were both basal and PGE1-stimulated activities decreased. Similarly, the PGE1-induced activation of the low Km GTPase was not or was only partially reduced by NEM. Adenylate cyclase activation by stable GTP analogs, NaF, and cholera toxin was also not decreased by NEM pretreatment. Exposure of intact platelets to NEM did not reduce alpha-adrenoceptor number and affinities for agonists and antagonists, as determined by [3H]yohimbine binding in platelet particles. The data indicate that NEM uncouples alpha-adrenoceptor-mediated inhibition of platelet adenylate cyclase, leaving the receptor recognition site and the adenylate cyclase itself relatively intact. Although the effect of NEM may be based on a reaction with the alpha-adrenoceptor site interacting with a coupling component, the selective loss of the adenylate cyclase inhibition together with an even increased stimulation of the enzyme by PGE1 suggests that there are two at least partially distinct regulatory sites involved in opposing hormonal regulations of adenylate cyclase activity, with that involved in hormonal inhibition being highly susceptible to inactivation by NEM.

Adenylyl Cyclases↗

Scrapie-infected cells, isolated prions, and recombinant prion protein: a comparative study.

Fourier -transform infrared microscopic spectra of scrapie-infected nervous tissue measured at high spatial resolution (approximately 6 microm) were compared with those obtained from the purified, partly proteinase K digested scrapie isoform of the prion protein isolated from nervous tissue of hamsters infected with the same scrapie strain (263K) to elucidate similarities/dissimilarities between prion structure investigated in situ and ex vivo. A further comparison is drawn to the recombinant Syrian hamster prion protein SHaPrP(90-232) after in vitro conformational transition from the predominantly alpha-helical isoform to beta-sheet-rich structures. It is shown that prion protein structure can be investigated within tissue and that detectability of regions with elevated beta-sheet content as observed in microspectra of prion-infected tissue strongly depends on spatial resolution of the experiment.

Animals↗

[Assessment and therapeutic possibilities in posthemorrhagic hydrocephalus of the newborn infant].

Internal hydrocephalus follows intraventricular hemorrhage in about 10%. Progression is directly related to the degree of hemorrhage. Several studies confirmed that cerebral damage may occur without an increase of intracranial pressure or head circumference. Assessment and therapeutic consequences depend entirely on sonographic and clinical criteria. In our series, 40 of 135 neonates with intraventricular hemorrhage developed internal hydrocephalus. Therapy was necessary in 35 children, 11 died. Serial lumbar punctures were the most frequent therapeutic approach in 70% of the children. 40% required a shunt, usually a ventriculo-peritoneal system. In this group the proportion of Grade III and IV hemorrhage was high. In 25% external drainage for one week was necessary. 10% were treated with acetazolamide and furosemide. By this therapy shunt placement could be avoided in 9 children (69.2%), in the group with Grade III hemorrhage. In addition it was possible to postpone shunting to the third month on the average. 25 children were followed-up. 40% were normal or had a mild developmental delay. 60% were seriously handicapped. Poor neurodevelopmental outcome was related directly to hemorrhage Grade III and IV, therefore to brain damage in the early phase. To prevent additional lesions it should be emphasized that in infantile hydrocephalus best long-term results have been obtained if the process was controlled early rather than later.

Brain Damage, Chronic↗

[High frequency oscillatory ventilation of infants with severe respiratory disorders: possibilities, risks and limits].

By pediatricians the high frequency oscillatory ventilation (HFOV) is used almost only in the neonatal period. We report on the administration of HFOV in infants with pulmonary insufficiency after failure of conventional ventilatory support. 6 infants (aged 2-7 months, all former preterm babies) were referred to our hospital due to severe pneumonia after unsuccessful conservative management. Indications for HFOV were hypoxia (mean paO2 41.8 mm Hg with FiO2 = 0.95 and mean airway pressure = 16.6 cm H2O) and/or air leak syndrome. In all cases a sufficient oxygenation could be achieved by HFOV, followed then by stepwise reduction of FiO2 and MAP. The air leaks receded. After 12-178 h on HFOV a successful switchback to conventional ventilatory support (at FiO2 = 0.48 and MAP < 12 cm H2O) was possible, all infants were extubated 6-15 days later. Possible risks of HFOV are air leaks, a necrotizing tracheobronchitis and hemodynamic changes due to compression of the heart and great vessels. With the at the moment in Germany available oscillatory ventilators HFOV as a rescue therapy must be limited for infants with a body weight below 5-6 kg.

Female↗