Amoeboid motion in confined geometry.

Many eukaryotic cells undergo frequent shape changes (described as amoeboid motion) that enable them to move forward. We investigate the effect of confinement on a minimal model of amoeboid swimmer. A complex picture emerges: (i) The swimmer's nature (i.e., either pusher or puller) can be modified by confinement, thus suggesting that this is not an intrinsic property of the swimmer. This swimming nature transition stems from intricate internal degrees of freedom of membrane deformation. (ii) The swimming speed might increase with increasing confinement before decreasing again for stronger confinements. (iii) A straight amoeoboid swimmer's trajectory in the channel can become unstable, and ample lateral excursions of the swimmer prevail. This happens for both pusher- and puller-type swimmers. For weak confinement, these excursions are symmetric, while they become asymmetric at stronger confinement, whereby the swimmer is located closer to one of the two walls. In this study, we combine numerical and theoretical analyses.

Plasma prilocaine and mepivacaine concentrations after combined lumbosacral plexus block.

In a pharmacokinetic study of combined sciatic/3-in-1 block for lower limb surgery, the two moderate-acting local anaesthetics prilocaine and mepivacaine were compared. The mean maximum venous plasma concentrations of mepivacaine were more than twice as high as when prilocaine was used as anaesthetic (5.1 micrograms/ml vs. 2.37 micrograms/ml). When used in combination with the former, ornipressin did not reduce plasma concentrations of mepivacaine to values which were below the threshold for toxic symptoms (5-6 mg/ml). The peak plasma concentrations exceeded the threshold of 5 micrograms/ml in four of the nine patients of the mepivacaine group (maximum value 7.21 mg/ml) and in two of the nine patients of the mepivacaine+ornipressin group (maximum value 8.61 micrograms/ml).

[Epidural blockade for analgesia and treatment of acute pancreatitis]. / Epidurale Blockade zur Analgesie und Behandlung der akuten Pankreatitis.

The effect of a fractional epidural blockade on acute pancreatitis was investigated in a prospective study. PATIENTS AND METHODS. Thoracic (20 patients) or lumbar (six patients) epidural blockade was carried out in 26 patients with severe abdominal conditions comprising sub-ileus in 100%, pancreatic edema indicated by sonography/computer tomography in 57.8%, and necrosis of the pancreas in 34.6%. RESULTS. On average, 3.4 (1-6) injections with single doses of 6-20 ml 0.25% bupivacaine were injected per day. In four patients, morphine (up to 4 mg per 24 h) was added to the local anesthetic. The duration of treatment was between 1 and 15 days. After 10.5% of the injections, the systolic pressure decreased by more than 20%, and after 12.8% of the injections the blood pressure decreased by more than 30%. Hypotension of more than 30% was treated with 0.3 to 0.5 ml theodrenaline (Akrinor) and/or 0.1 to 0.2 mg dihydro-ergotamine (Dihydergot). General analgesics had to be administered in addition on 21.8% of the treatment days and intensive care treatment (artificial ventilation) on 32% of the treatment days. The duration of epidural analgesia varied between 1 and 15 days depending on the intensity of symptoms (pain, ileus). Within 4 days, the enzyme activity of the lipase fell from 8120 to 427 IU, and that of alpha amylase fell from 1401 to 143 IU. In 3 patients laparotomy (for drainage) was performed. An ERCP was carried out in 16 patients. Cardiopulmonary failure necessitated artificial ventilation over a period of 1-15 days in 6 patients; the epidural blockade was continued during the artificial ventilation. Cholecystectomy was carried out as an interval operation in 6 patients. No neurological complications were observed. All patients survived and were discharged from hospital.

[The single intercostal block--surgical and therapeutic indications]. / Die einzeitige Interkostalblockade--operative und therapeutische Indikationen.

Since the first paravertebral blockade was carried out by Sellheim in 1905, this method has proved effective for the isolated blockade of spinal nerves. The efficacy of preoperative intercostal blockade (ICB) in combination with neuroleptanalgesia (NLA) or Pentothal-pentazocine-N2O anesthesia (Pe-Pz) was studied (unilateral analgesia for cholecystectomy). Group 1: NLA; group 2: NLA with ICB; group 3: Pe-Pz; group 4: Pe-Pz with ICB. The analgesic requirement differed significantly between groups 1 (0.33 mg fentanyl) and 2 (0.15 mg fentanyl) and groups 3 (63.5 mg pentazocine) and 4 (31.5 mg pentazocine). There were also significant differences in circulatory responses. The maximum deviation from the initial value at the beginning of the operation in group 1 compared to group 2 was pulse rate + 28.7% vs + 2.4%, mean arterial pressure (Part) + 24.6% vs + 3.1%, and systolic pressure (Psyst) + 33% vs +/- 0%; group 3 compared to group 4: pulse rate + 16.4% vs + 3.2%, Part + 24.5% vs 0.0%, and Psyst + 26.5% vs + 196. The times of action of ICB extended from 7.54 h to 11.33 h for partial analgeisa, time to the first dose of analgesic from 12.3 h to 16.9 h (etidocaine 0.5% and 1% respectively without and with epinephrine). The mean blood levels after 100 mg bupivacaine-CO2 rose to 1.16 micrograms/ml after 5 min and reached a maximum after 15 min (1.29 micrograms/ml) as compared to 0.98 micrograms/ml after addition of ornithine-vasopressin. These values are very much higher than those after the use of bupivacaine-HCl solution. Etidocaine and bupivacaine-HCl have comparable durations of analgesia. Toxicologically, both substances can be applied safely with consideration of all pharmacological data for ICB. Of a total of 3,485 intercostal blockades, 2,775 were applied perioperatively (pre- and postoperatively); 265 were carried out for trauma patients (rib fractures) and 445 for therapeutic indications (herpes zoster neuralgia, tumor pain, costovertebral pain). In 8 blocks 10% ammonium sulfate, in 4 blocks absolute alcohol, and in 19 blocks 5% phenol were used for neurolysis. In 2 cases a marginal pneumothorax was seen, which was resorbed spontaneously (0.06%). Altogether 16,270 single intercostal nerves were blocked. Single-session intercostal blockade can be combined as unilateral analgesia with general anesthesia. This combination is characterized by stable circulatory conditions with avoidance of hypertensive reactions. The long-lasting analgesia allows early mobilization and physiotherapy both postoperatively and posttraumatically in patients with unilateral thoracic and abdominal pain.(ABSTRACT TRUNCATED AT 400 WORDS)

[How safe is the rectal induction of narcosis with methohexital in pediatric anesthesia?]. / Wie sicher ist die rektale Narkoseeinleitung mit Methohexital in der Kinderanaesthesie?

A 6 year old boy developed a rebound of anaesthesia with abolition of reflexes and spontaneous respiration 100 min after anorectal induction with methohexitone and 20 min after extubation. The role of reliable observation during postoperative period in this type of anaesthesia is emphasized.

[Regional anesthesia in abdominal surgery]. / Die Regionalanaesthesie in der Abdominal-Chirurgie.

Spinal and peridural anesthesia are most useful in lower abdominal operations. For upper laparotomies needing analgesia, good relaxation and quiet ventilation, intercostal block and peridural anesthesia with light general anesthesia are suitable techniques to avoid hypertension and metabolic responses (hyperglycemia, cortisol). During the postoperative period, regional blocks improve lung function and bowel motility, and afford early ambulation.