Developmental, nutritional and hormonal anomalies of weightlessness-grown wheat.

The behavior of water in weightlessness, as occurs in orbiting spacecraft, presents multiple challenges for plant growth. Soils remain saturated, impeding aeration, and leaf surfaces remain wet, impeding gas exchange. Herein we report developmental and biochemical anomalies of "Super Dwarf" wheat (Triticum aestivum L.) grown aboard Space Station Mir during the 1996-97 "Greenhouse 2" experiment. Leaves of Mir-grown wheat were hyperhydric, senesced precociously and accumulated aromatic and branched-chain amino acids typical of tissues experiencing oxidative stress. The highest levels of stress-specific amino acids occurred in precociously-senescing leaves. Our results suggest that the leaf ventilation system of the Svet Greenhouse failed to remove sufficient boundary layer water, thus leading to poor gas exchange and onset of oxidative stress. As oxidative stress in plants has been observed in recent space-flight experiments, we recommend that percentage water content in apoplast free-spaces of leaves be used to evaluate leaf ventilation effectiveness. Mir-grown plants also tillered excessively. Crowns and culms of these plants contained low levels of abscisic acid but high levels of cytokinins. High ethylene levels may have suppressed abscisic acid synthesis, thus permitting cytokinins to accumulate and tillering to occur.

Isolation of syncytiotrophoblast microvesicles and exosomes and their characterisation by multicolour flow cytometry and fluorescence Nanoparticle Tracking Analysis.

The human placenta releases multiple types and sizes of syncytiotrophoblast (STB) extracellular vesicles (EV) into the maternal circulation that exhibit diverse biological activities. The placental perfusion technique enables isolation of these STBEV, but conventional flow cytometry can only be used to phenotype EV down to ∼300 nm in size. Fluorescence Nanoparticle Tracking Analysis (fl-NTA) has the potential to phenotype EV down to ∼50 nm, thereby improving current characterisation techniques. The aims of this study were to prepare microvesicle and exosome enriched fractions from human placental perfusate (n=8) and improve fl-NTA STBEV detection. Differential centrifugation and filtration effectively removed contaminating red blood cells from fresh placental perfusates and pelleted a STB microvesicle (STBMV) fraction (10,000×g pellet - 10KP; NTA modal size 395±12 nm), enriched for the STB marker placental alkaline phosphatase (PLAP) and a STB exosome (STBEX) fraction (150,000×g pellet - 150KP; NTA modal size 147±6 nm), enriched for PLAP and exosome markers Alix and CD63. The PLAP positivity of 'standard' 10KP and 150KP pools (four samples/pool), determined by immunobead depletion, was used to optimise fl-NTA camera settings. Individual 10KP and 150KP samples (n=8) were 54.5±5.7% (range 17.8-66.9%) and 30.6±5.6% (range 3.3-51.7%) PLAP positive, respectively. We have developed a reliable method for enriching STBMV and STBEX from placental perfusate. We also standardised fl-NTA settings and improved measurement of PLAP positive EV in STBMV. However, fl-NTA is not as sensitive as anti-PLAP Dynabead capture for STBEX detection, possibly due to STBEX having lower surface expression of PLAP. These important developments will facilitate more detailed studies of the role of STBMV and STBEX in normal and pathological pregnancies.

Accurate particle size distribution determination by nanoparticle tracking analysis based on 2-D Brownian dynamics simulation.

A physical model is presented to simulate the average step length distribution during nanoparticle tracking analysis experiments as a function of the particle size distribution and the distribution of the number of steps within the tracks. Considering only tracks of at least five steps, numerical simulation could be replaced by a normal distribution approximation. Based on this model, simulation of a step length distribution allows obtaining a much more reliable estimation of the particle size distribution, thereby reducing the artificial broadening of the distribution, as is typically observed by direct conversion of step length to particle size data. As this fitting procedure also allowed including data from particles that were followed for a relatively low number of steps, the measurement time could be reduced for particles that are known to be monodisperse. Whereas the inversion is less sensitive towards the particle size distribution width, still similar values were obtained for both the average diameter and standard deviation of a polystyrene latex sample irrespective of the track length, provided that the latter included at least five steps.

Minimally invasive photodynamic therapy (PDT) for ablation of experimental rat glioma.

OBJECTIVE: The feasibility of using ALA-mediated photodynamic therapy (PDT) tumor ablation as a minimally invasive treatment alternative for malignant brain tumors was evaluated in a rodent model. Treatment efficacy and side effects were evaluated with MRI, histopathology and survival rates. METHODS: BT (4)C orthotopic brain tumors were induced in BD-IX rats. At various time intervals following tumor induction the animals were given 5-aminolevulinic acid (ALA) and 4 hours later optical fibers were inserted directly into the tumor without mechanical debulking or cranial decompression. A 3-day course of steroid treatment was initiated immediately prior to PDT. RESULTS: All untreated animals inevitably died within one month after tumor implantation (28.5 +/- 2.5 days). Complete tumor eradication was achieved in only 1/17 rats, but a significant increase in survival was obtained in the group of animals receiving 125 mg/kg ALA and 26 Joules of light fluence. Histopathology revealed large areas of central tumor necrosis, although clusters of viable tumor cells were often found at the tumor periphery. Pronounced edema in the necrotic tumor center as well as in the surrounding brain, and along white matter tracts was evident in all the brains studied from PDT-treated animal. CONCLUSION: This study suggests that ALA-mediated PDT may become a promising alternative therapy for the minimally invasive treatment of brain tumors. A judicious choice of PDT regimens that minimizes inflammatory responses through the use multiple fractionated long-term treatment protocols would likely be required.

Long-term home treatment with epidural analgesia does not affect later spinal cord stimulation in patients with otherwise intractable angina pectoris.

OBJECTIVE: The only way some patients with intractable angina pectoris can endure the daily pain is by using opiates. Epidural morphine or spinal cord stimulation (SCS) for out-patients is a possibility for this patient group. The aim of this study was to determine whether patients previously treated with epidural injections had more frequent electrode migration, higher stimulation needs, and less effect of SCS treatment. DESIGN: A prospective, nonrandomized study with a 4-year follow-up period. SETTING: Department of Anaesthesia, Pain Section. A referral center in institutional practice. Ambulatory care. PATIENTS: The patient group comprised 53 patients; all had been treated daily with opiates. A total of 26 patients had epidural catheters for a mean time of 1 year before SCS. All patients had intractable angina pectoris. For these patients, further angioplasty or coronary bypass surgery was not technically possible. Even with maximal medication, it was impossible to cope with the patients' angina pectoris, and the only way the patients could endure the daily pain was by using opiates. Therefore, alternative therapies were considered to give these patients palliation. INTERVENTION: SCS with epidural electrodes stimulating paresthesia in the area where angina is perceived. MAIN OUTCOME MEASURE: Difference for the patients previously treated with epidural catheters in stimulation amplitude, frequency of electrode migration, and effect of SCS. RESULTS: Stimulation demand (p = 0.09), frequency of electrode migrations (p = 0.46), and pain-reducing effect (p = 0.16) were not different for the group of patients previously treated with epidural catheters for longer periods (1-36 months). CONCLUSIONS: SCS in patients previously treated with epidural catheters has an effect equal to that in other patients.

Ground-based studies with Super-Dwarf wheat in preparation for space flight.

Several experiments were carried out to test responses of a Super-Dwarf cultivar of wheat (Triticum aestivum L.) to various environmental parameters that were anticipated to be present in our attempts to grow the wheat in a small growth chamber on the Russian Space Station, Mir, or that proved to be present in a 1995 trial space experiment. Under low photosynthetic photon flux (40-400 micromoles m-2 s-1 PPF), development (e.g. anthesis) was retarded, but heads (often sterile) always formed, even if light was so low that plants died before the heads could mature. Longer photoperiods promoted flowering, but night interruptions combined with short days did not provoke a long-day response as occurs with true long-day plants. The long-day effect could prove to be a summation of photosynthetic products. Heat stress (40 degrees C for 1-24 h) did not influence flowering but killed plants that were 13-16-day-old (no effect on younger plants). Concentrations of iodine or silver-fluoride disinfectants present in the water used for plants on Mir (1.0-4.0 mg L-1) did not affect plant growth although higher concentrations (8.0-1.6 mg L-1) were inhibitory. GA3 or indoleacetic acid applied every other day at concentrations from 1.0 x 10(-6) mg L-1 to 3.162 x 10(-4) mg L-1 did not change the height of Super-Dwarf wheat, suggesting that this cultivar is not a gibberellin mutant.

Postoperative pain management in children has been improved, but can be further optimized.

The aim of this study is to evaluate the effect of the analgesic treatment currently used in children, and to identify if problems can be related to any particular routine or group of children. Analgesics administered pre-, per- and postoperatively were recorded, and intensity of pain during rest and movement and incidence and severity of side effects were measured four times postoperatively. Fifty-nine children aged 3 to 15 years undergoing miscellaneous operations participated. All children received analgesic treatment. During the study period 26 children reported at least one episode of unacceptable pain, while unacceptable pruritus, nausea or vomiting were observed in 18 children. It was not possible to relate the incidence of pain and side effects to any particular analgesic treatment or type of surgery, but groups of children that might need additional attention were identified. Even though improvements have been obtained, it is still a challenge to optimize the postoperative pain management of children, and when doing so attention should be paid not only to pain relief, but also to side effects of the administered analgesics.

[Postoperative pain relief in children]. / Postoperativ smertebehandling af børn.

Postoperative pain management in children has been subject to increasing interest during the last decade, but is still insufficient. A survey is presented concerning postoperative pain management in children. The value of monitoring the pain as well as the opioid side effects in children is stressed, and such methods are presented. Acute Pain Service is mentioned and the most important pharmacological aspects regarding non-steroidal anti-inflammatory drugs, paracetamol, opioids and local anaesthetics are discussed. The management of postoperative pain in neonates is reviewed separately. It is concluded that the present insufficient management of postoperative pain in children is not due to the lack of methods and techniques, but rather to lack of sufficient utilization and comprehension of the possibilities. Moreover, pain management in children should be individualised. It is also necessary to be more aware of side effects of the pharmacological treatment.

Age-related postoperative morphine requirements in children following major surgery--an assessment using patient-controlled analgesia (PCA).

To investigate if small children require less morphine for postoperative analgesia than do older children and adolescents we analysed the morphine consumption pattern of 28 consecutive children on intravenous patient-controlled analgesia (PCA) following major surgery. The median age-specific morphine requirements between 2 comparable groups of children aged 4-8 years and 9-15 years were compared. We used the Pharmacia-Deltec pump in all children and the same settings: a bolus dose of 25 microgram/kg, an 8 minutes lockout interval and no background infusion. In addition, all children received paracetamol as a supplemently to the morphine. In this study children aged 4-8 years had significantly higher total postoperative morphine requirements compared to children aged 9-15 years, i.e. 11.6 microgram/kg/hour and 7.5 microgram/kg/hour respectively (p = 0.037). Hence, we conclude that children of this age group may have a higher total postoperative morphine requirement following major surgery than older children and adolescents.

Durability of central venous catheters. A randomized trial in children with malignant diseases.

In a prospective randomized study the durability of tunnelled and non-tunnelled central venous catheters was investigated in children with malignant diseases. Twenty children were included in the study but four (two in each group) had to be excluded; three because the entry criteria turned out not to be fulfilled and one because of lack of data. The median duration of the tunnelled catheters was 224 days with a range of 25-846 days which was significantly longer than that of conventional catheters (39.5 days, range 9-228 days). In addition six of eight conventional catheters were accidentally removed whereas all catheters in the tunnelled group had to be removed via a small incision. Three cases of catheter related sepsis, two in the tunnelled group and one in the conventional group, were registered. The corresponding number of infections per catheter days were 1 in 1189 days and 1 in 522 days, respectively. In conclusion cuffed, tunnelled central venous catheters are less prone to displacement than traditional percutaneous central venous catheters when used in children with malignant diseases.

Laryngeal mask airway guided tracheal intubation in a neonate with the Pierre Robin syndrome.

Endotracheal intubation in infants with the Pierre Robin syndrome may sometimes be impossible to accomplish by conventional means. To aid difficult tracheal intubation many different techniques have been described. We present a case, in which we successfully intubated a small-for-date newborn boy with the Pierre Robin syndrome by using a modified laryngeal mask airway (no. 1) as a guide for the endotracheal tube. The technique is easy to perform, less traumatic and less time-consuming than multiple attempts at laryngoscopy or blind tracheal intubation.

Does pain relief with spinal cord stimulation for angina conceal myocardial infarction?

OBJECTIVE: To investigate the possibility that spinal cord stimulation (SCS) used for pain relief can conceal acute myocardial infarction (AMI). DESIGN: Prospective evaluation of patients treated with SCS. SETTING: University hospital. PATIENTS: 50 patients with coronary artery disease and severe, otherwise intractable angina treated with SCS for 1-57 months. MAIN OUTCOME MEASURES: Necropsy findings, symptoms, serum enzyme concentrations, electrocardiographic changes. RESULTS: Ten patients were considered to have had AMI. In nine of these SCS did not conceal precordial pain and in one patient no information about precordial pain could be obtained. CONCLUSION: There was no evidence that SCS concealed acute myocardial infarction.

Nitrous oxide does not influence operating conditions or postoperative course in colonic surgery.

We studied 150 patients undergoing elective colonic surgery; they were allocated randomly to undergo artificial ventilation with either air-oxygen or nitrous oxide-oxygen during surgery. Eleven patients were excluded. Preoperative management, surgery and postoperative analgesia were similar in both groups. Anaesthesia included propofol by infusion, pancuronium and fentanyl 3 micrograms kg-1 h-1. The air-oxygen group required a continuous infusion of propofol of 4-6 mg kg-1 h-1 whereas the nitrous oxide-oxygen group required only 1-2 mg kg-1 h-1. There were no differences between the groups in duration of anaesthesia, distension of the bowel and postoperative bowel function. The postoperative hospital stay was similar for both groups.

Epidural morphine for postoperative pain relief in children.

Epidural morphine for postoperative pain relief is in general use, and has proved to be very efficient in adults. The epidural technique and the use of epidural morphine are much less frequent in children. For 2 years we have prospectively followed 76 children who had epidural morphine for postoperative pain relief after major abdominal surgery. The age distribution was from newborn to 13 years, with a median age of 12 months. It was estimated that 94% of the patients had good analgesia for the first 24 postoperative hours and no other opioids were given. The side effects were few, but one case of respiratory depression was seen and 20% of the children had pruritus. There were four dural punctures and three catheters slipped out accidentally, but otherwise the treatment was continued as long as it was considered necessary (1-11 days). The use of postoperative ventilatory support decreased during the investigation. We observed a change in the sleeping pattern with an increased number of sleep-induced myoclonia during the administration of epidural morphine. In conclusion, the use of epidural morphine in children for postoperative pain relief is very efficient. The minimal effective dose has not been established as yet, but 50 micrograms/kg every 8 h, supplemented with small doses of bupivacaine, provides excellent analgesia in the immediate postoperative period after major abdominal surgery. The side effects are few, but the risk of respiratory depression is always present and observation in the intensive care unit or recovery for the first 24 h is strongly recommended.

[Patient-controlled analgesia in children]. / Patientkontrolleret smertebehandling af børn.

In order to introduce intravenous patient-controlled analgesia (PCA) in children in the Department of Anaesthesiology and Intensive Care, Odense University Hospital, we evaluated the technique in 13 children following major orthopaedic or abdominal surgery. The pump (Pharmacia-Deltec, CADD-PCA) was loaded with 1 mg/ml morphine in a 50 milliliters cassette. A bolus dose of 25 micrograms/kg and a lock-out interval of eight minutes were the initial settings. The morphine dose used, pain scores and side effects were currently recorded. Ages ranged from 4-15 years (mean 10.5 years) and the method was used for a mean of 89 hours (range 57-144 hours) postoperatively. Morphine requirements averaged 9.5 microgram/kg/hour (range 5.4-15.6 microgram/kg/hour). Pain control was good and side effects were few and of minor nature. PCA is an effective and safe means of providing good quality analgesia in children.

Enhancement of Anaerobic Respiration in Root Tips of Zea mays following Low-Oxygen (Hypoxic) Acclimation.

Root tips (10-millimeter length) were excised from hypoxically pretreated (HPT, 4% [v/v] oxygen at 25 degrees C for 16 hours) or nonhypoxically pretreated (NHPT, 40% [v/v] oxygen) maize (Zea mays) plants, and their rates of respiration were compared by respirometry under aerobic and anaerobic conditions with exogenous glucose. The respiratory quotient under aerobic conditions with 50 millimolar glucose was approximately 1.0, which is consistent with glucose or other hexose sugars being utilized as the predominant carbon source in glycolysis. Under strictly anaerobic conditions (anoxia), glycolysis was accelerated appreciably in both HPT and NHPT root tips, but the rate of anaerobic respiration quickly declined in NHPT roots. [U-(14)C]Glucose supplied under anaerobic conditions was taken up and respired by HPT root tips up to five times more rapidly than by NHPT roots. When anaerobic ethanol production was measured with excised root tips in 50 millimolar glucose, HPT tissues consistently produced ethanol more rapidly than NHPT tissues. These data suggest that a period of low oxygen partial pressure is necessary to permit adequate acclimation of the root tip of maize to subsequent anoxia, resulting in more rapid rates of fermentation and generation of ATP.

[Incapacitating angina pectoris treated with electric stimulation of the spinal cord]. / Invaliderende angina pectoris behandlet med elektrisk rygmarvsstimulation (ERS).

Thirty patients who had severe incapacitating angina pectoris which had not reacted to the conventional therapeutic measures and which required massive daily opioid consumption were treated with electrical spinal cord stimulation (SCS) by means of a completely implantable stimulation system. The therapeutic effect was good in 87% of the patients who experienced considerably reduced frequency of attacks and markedly reduced opioid consumption (p less than 0.00005). Nine of the patients could reduce opioid consumption and 14 out of 27 could cease their otherwise daily opioid consumption. In four patients, the therapeutic effect was unsatisfactory. In the first 22 patients in whom a unipolar electrode was introduced, displacement of the electrode and subsequent reoperation was a frequent problem. This problem disappeared after change to multipolar electrodes as slight changes in placing of the electrode could easily be compensated for via the external programming equipment. This investigation reveals that SCS is a good therapeutic alternative for this selected patient category.

Evaluation of intensified prehospital treatment in out-of-hospital cardiac arrest: survival and cerebral prognosis. The Odense ambulance study.

During a period of 3 years three different types of emergency medical service (EMS) systems were evaluated in a city with about 238,000 inhabitants/population density of 570/km2. Included were 393 out-of-hospital cardiac arrest patients in whom prehospital cardiopulmonary resuscitation was provided by personnel on basic, intermediate, or advanced care training. When ordinary ambulances (basic EMS) were used, 8 (5%) patients were discharged alive. When ambulances with specially trained paramedics (intermediate EMS) were used, 2 (1%) patients were discharged. Finally medically staffed ambulances with doctors collaborating (advanced EMS) were used, and 11 (13%) patients were discharged. The intermediate EMS system was used in another area with 45,000 inhabitants/population density of 340/km2, and in this area 20 (18%) patients were discharged. Among the survivors a psychological assessment in form of a test for dementia was assessed in long-term survivors (n = 30) together with 28 patients surviving acute myocardial infarction and 11 control persons. The results of the investigation demonstrate that the more intensive the prehospital treatment of out-of-hospital cardiac arrest, the more patients survive and the more patients survive with good cerebral function. However, the ambulances with specially trained paramedics were only effective in the area with 340 inhabitants/km2.