Thrombogenicity of metallic vascular stents in arteries and veins--an experimental study in pigs

Endovascular expanding metallic stents were percutaneously implanted in the iliac arteries and veins of pigs. The vessels had been stenosed by a ligature of catgut 4 weeks prior to this. Platelets were labeled with Indium 111 and the deposition onto the dilated and stented areas was dynamically registered for 240 min with a scintillation camera. All six arterial and six venous stents remained patent throughout the examination period. At the site of arterial stenting there was an increase, of deposited activity, and in the veins a decrease. These experimental findings support the use of endovascular stents after dilation, especially in venous stenoses.     

Schistosoma mansoni : cercarial shedding patterns from a mixed infection of Biomphalaria glabrata with two (early and late) chronobiological variants

 The cercarial emergence rhythms of Schistosoma mansoni were analyzed for mixed infection of the snail Biomphalaria glabrata with two chronobiological strains, one with an early shedding pattern and the other with a late shedding pattern. Under these conditions, each parasite strain kept its own circadian cercarial emergence pattern. When the chronobiological variants were of the same species, no interference between the trematode larvae occurred during the cercarial emergence process. These results confirm that within the host-parasite system the parasite component is directly responsible for the cercarial emergence pattern. Received: 16 September 1996 / Accepted: 18 October 1996     

Enlarged adenomectomy for enclosed prolactinomas: A preliminary study of 26 cases

Summary Preliminary results obtained from 26 cases of prolactinomas less than 20 mm in diameter after treatment by enlarged adenomectomy are described.The operation consisted in removal of the adenoma, a layer of normal pituitary at the outer edge of the tumour and the pituitary capsule in contact with the sellar meninges. 24 women and 2 men were involved whose prolactin levels (PRL) were less than 200 ng/ ml. All presented abnormal PRL responses to Thyrotropin releasing hormone (TRH) and Metoclopramide (MCP) tests and an absence of a nocturnal rise in the sleep cycle study. Postoperatively, three patients developed transitory diabetes insipidus and five transitory adrenal insufficiency. Gonadotropin reserve was always found normal. All 24 women resumed normal menstrual cycles and two became pregnant within one year. From a serological viewpoint, after surgery 100% of patients were found to be normal for levels of prolactin but only 85% turned to normal dynamic tests. The results of this small series of enlarged adenomectomies seem better than those obtained using selective adenomectomy, but must be confirmed with time.     

Cholinergic receptors in the extraocular rectus muscle of the rabbit

The cholinergic receptors in rabbit isolated rectus muscle preparations were characterized by means of cholinergic agonists and antagonists. The concentration-dependent contraction induced by acetylcholine, carbachol or oxotremorine remained uninfluenced by atropine (10(-5) M), whereas the nicotinic receptor antagonist hexamethonium caused a parallel shift of the concentration-response curve. The agonists pilocarpine, methacholine and aceclidine, which are selective muscarinic receptor stimulants, did not cause contraction of the muscle preparation. However, the nicotinic receptor stimulant 1,1-dimethyl-4-phenylpiperazine iodide (DMPP) caused contraction similar to that induced by acetylcholine. DMPP-induced contractions were inhibited by hexamethonium, causing a parallel rightward shift of the concentration-response curve. This shift could be quantified by means of a Schild plot, indicating competitive antagonism with a PA2 value of 4.63 for hexamethonium. Atropine when applied together with hexamethonium did not cause a further shift of the concentration-response curve. The present results clearly indicate that the cholinergic receptors which mediate contraction in the rabbit isolated extraocular muscle preparation belong to the nicotinic subtype.     

Maschineller und manueller Bronchusverschluß —ergebnisse einer konsekutiven untersuchungsserie

Zusammenfassung Experimentelle Untersuchungen haben für den maschinellen Bronchusverschluß nach Lobektomie und Pneumonektomie im Vergleich zu anderen Nahtmaterialien die geringste Entzündungsrate und die höchste Zugfestigkeit ergeben. In einer konsekutiven Serie von 233 Lungenresektionen der Chirurgischen Kliniken Köln-Lindenthal und der Klinik für Allgemein- und Abdominalchirurgie der Johannes Gutenberg-Universität Mainz ging die Häufigkeit einer Bronchus-stumpfinsuffizienz von 7,1% nach manuellem Bronchusverschluß auf 2,0% und die insuffizienzbedingte Letalität auf 0,7% bei Anwendung des Klammergeräts zurück. Die wesentlichen Vorteile des maschinellen Bronchusverschlusses sind die Einfachheit der Anwendung, die Schnelligkeit und die Gleichmäßigkeit des Verschlusses. Damit stellen die Klammernahtgeräte bei Lungenresektionen eine wertvolle Ergänzung der Operationstechnik dar.

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Mechanical and manual bronchial closure —results of a consecutive trial

Summary After lobectomy and pneumonectomy in experimental evaluations stapled bronchial closures showed the lowest incidence of inflammatory reaction and the highest strength determined by leakage pressure compared with other suture material. A total of 233 lung resections - performed at Surgical University Clinic Köln-Lindenthal and the Clinic for General and Abdominal Surgery of the Johannes-Gutenberg-Universität Mainz — were reviewed. Mechanical stapling reduced the rate of bronchopleural fistulas to 2.0% compared with 7.1 % after manual suturing. In parallel, mortality related to bronchial stump leakage decreased to 0.7%. Main advantages of bronchial closure with staplers are the simplicity of their use, the speed and the uniformity of the closure. Thereby stapling devices are valuable completions in pulmonary surgery.