Recovery Of Respiration Research Articles

Regulatory peptides protect brain neurons from hypoxia in vivo

Short peptides that have been characterized in previous studies performed in the St. Petersburg Institute of Bioregulation and Gerontology of the Northeastern Division of the Russian Academy of Medical Sciences [1‐3] protect neurons from oxidative stress [4]; however, under in vitro conditions, the peptide action has been observed at high (millimolar) concentrations. The anti-oxidant activity of these peptides is not high; therefore, their biological effect could be mediated by a natural system of antioxidant defense [5]. If this is the case, the peptide protective effect could be observed at almost physiological concentrations under the in vivo conditions. This was aimed at verifying this assumption. The protective effect of short regulatory peptides (vilon, epitalon, pinealon, and vesugen) was studied under the conditions of oxidative stress caused in animals by hypobaric hypoxia. Male Wistar rats weighing 185‐200 g were used in our experiments. Oxidative stress was induced under the conditions of hypobaric hypoxia in an altitude chamber with adjustable airflow, which prevented hypercapnia [6]. By means of a vacuum pump, the pressure in the altitude chamber was reduced to 0.125 atm for 1 min. Under these conditions, the animals were kept until respiration arrest; after this, the animals were returned to the normal-pressure conditions by supplying air into the chamber for 1 min. The following parameters were recorded: the time (s) until the respiration arrest “at the height”; the time (s) of posture recovery, i.e., the period from respiration arrest to the moment when the experimental animal assumed normal posture after “descending from the height” and respiration recovery under normobaric conditions; and the restitution time (s), the total duration of the recovery of physiological activity after hypoxia. To determine the protective effect of the peptides studied, the death rate and coefficient of restitution (the ratio of the restitution time to the time before respiration arrest in the altitude chamber) were estimated. The results obtained were processed statistically using the Mann‐Whitney and Kruskal‐Wallis tests; the differences were assumed to be significant at p < 0.05. The peptides vilon (Lys-Glu), vesugen (Lys-GluAsp), pinealon (Glu-Asp-Arg), and epitalon (Ala-GluAsp-Arg) were injected daily at a dose of 10 µ g/kg body weight intraperitoneously for five days before hypoxia. The rats of the control group were injected with saline according to the same scheme. Each group contained 10 animals.

Epidermal growth factor receptor ligands and renal epithelial cell proliferation

a critical issue in understanding how the mammalian kidney responds to pathological states and nephrotoxic chemicals involves the identification of modulating agents, growth factors, and signaling pathways that regulate responses. Although some of the modulating agents identified, including

Changes in Neuronal Expression of c-Fos Protein in the Medulla Oblongata after Unilateral Phrenicotomy in Wistar Rats

[Purpose] The purpose of this study was to examine changes in neuronal expression of c-Fos protein in the medulla oblongata after unilateral phrenicotomy in Wistar rats. [Subjects and Methods] After left side phrenicotomy, rats were maintained for 4 weeks (test experiments), then transcardially perfused with fixatives. Brain sections were prepared, and c-Fos protein induced in neurons in the medulla oblongata was immunohistochemically stained by the ABC method. Control rats were maintained for the same period after sham operation, and the brain sections were similarly processed as in the test experiments. [Results] The number of c-Fos immunoreactive (c-Fos-ir) neurons in the medulla oblongata was counted and their spatial distributions were mapped. In both sides of the ventral respiratory group (VRG) and the left side of dorsal respiratory group (DRG), numbers of c-Fos-ir neurons were significantly increased in phrenicotomy rats compared to the control rats (P<0.05). In the right side of the DRG, the number of c-Fos-ir neurons also increased but without statistical significance. Numbers of c-Fos-ir neurons in the VRG were greater than that in the DRG. [Conclusion] The present results suggest that phrenicotomy may result in an increase in the activity of medullary respiratory neurons during the recovery of respiration after the phrenicotomy. The specific activation of the neurons in the VRG and DRG during unilateral phrenic nerve paralysis could underlie the changes in regulation of the respiratory control center following unilateral phrenicotomy.

Desiccation-tolerance in bryophytes: a review

Abstract Desiccation-tolerance (DT), the ability to lose virtually all free intracellular water and then recover normal function upon rehydration, is one of the most remarkable features of bryophytes. The physiology of bryophytes differs in major respects from that of vascular plants by virtue of their smaller size; unlike vascular plants, the leafy shoots of bryophytes equilibrate rapidly with the water potential in their surroundings and tend to be either fully hydrated or desiccated and metabolically inactive. The time required to recover from desiccation increases and degree of recovery decreases with length of desiccation; both also depend upon temperature and intensity of desiccation. Tolerance in at least some species shows phenotypic plasticity. Recovery of respiration, photosynthesis and protein synthesis takes place within minutes or an hour or two; recovery of the cell cycle, food transport and the cytoskeleton may take 24 hours or more. Positive carbon balance is essential to survival of repea...

Metabolic processes sustaining the reviviscence of lichen Xanthoria elegans (Link) in high mountain environments.

To survive in high mountain environments lichens must adapt themselves to alternating periods of desiccation and hydration. Respiration and photosynthesis of the foliaceous lichen, Xanthoria elegans, in the dehydrated state were below the threshold of CO2-detection by infrared gas analysis. Following hydration, respiration totally recovered within seconds and photosynthesis within minutes. In order to identify metabolic processes that may contribute to the quick and efficient reactivation of lichen physiological processes, we analysed the metabolite profile of lichen thalli step by step during hydration/dehydration cycles, using 31P- and 13C-NMR. It appeared that the recovery of respiration was prepared during dehydration by the accumulation of a reserve of gluconate 6-P (glcn-6-P) and by the preservation of nucleotide pools, whereas glycolytic and photosynthetic intermediates like glucose 6-P and ribulose 1,5-diphosphate were absent. The large pools of polyols present in both X. elegans photo- and mycobiont are likely to contribute to the protection of cell constituents like nucleotides, proteins, and membrane lipids, and to preserve the integrity of intracellular structures during desiccation. Our data indicate that glcn-6-P accumulated due to activation of the oxidative pentose phosphate pathway, in response to a need for reducing power (NADPH) during the dehydration-triggered down-regulation of cell metabolism. On the contrary, glcn-6-P was metabolised immediately after hydration, supplying respiration with substrates during the replenishment of pools of glycolytic and photosynthetic intermediates. Finally, the high net photosynthetic activity of wet X. elegans thalli at low temperature may help this alpine lichen to take advantage of brief hydration opportunities such as ice melting, thus favouring its growth in harsh high mountain climates.

Desiccation tolerance in the moss Polytrichum formosum: physiological and fine-structural changes during desiccation and recovery.

This study explores basic physiological features and time relations of recovery of photosynthetic activity and CO2 uptake following rehydration of a desiccation-tolerant moss in relation to the full temporal sequence of cytological changes associated with recovery to the normal hydrated state. It seeks reconciliation of the apparently conflicting published physiological and cytological evidence on recovery from desiccation in bryophytes. Observations were made of water-stress responses and recovery using infrared gas analysis and modulated chlorophyll fluorescence, and of structural and ultrastructural changes by light and transmission electron microscopy. Net CO2 uptake fell to zero at approx. 40 % RWC, paralleling the fluorescence parameter PhiPSII at 200 micromol m(-2) s(-1) PPFD. On re-wetting the moss after 9-18 d desiccation, the initially negative net CO2 uptake became positive 10-30 min after re-wetting, restoring a net carbon balance after approx. 0.3-1 h. The parameter Fv/Fm reached approx. 80 % of its pre-desiccation value within approx. 10 min of re-wetting. In the presence of the protein-synthesis inhibitors chloramphenicol and cycloheximide, recovery of Fv/Fm (and CO2 exchange) proceeded normally in the dark, but declined rapidly in the light. Though initial recovery was rapid, both net CO2 uptake and Fv/Fm required approx. 24 h to recover completely to pre-desiccation values. The fixation protocols produced neither swelling of tissues nor plasmolysis. Thylakoids, grana and mitochondrial cristae remained intact throughout the drying-re-wetting cycle, but there were striking changes in the form of the organelles, especially the chloroplasts, which had prominent lobes and lamellar extensions in the normally hydrated state, but rounded off when desiccated, returning slowly to their normal state within approx. 24 h of re-wetting. Sub-cellular events during desiccation and re-wetting were generally similar to those seen in published data from the pteridophyte Selaginella lepidophylla. Initial recovery of respiration and photosynthesis (as of protein synthesis) is very rapid, and independent of protein synthesis, suggesting physical reactivation of systems conserved intact through desiccation and rehydration, but full recovery takes approx. 24 h. This is consistent with the cytological evidence, which shows the thylakoids and cristae remaining intact through the whole course of dehydration and rehydration. Substantial and co-ordinated changes in other cell components, which must affect spatial relationships of organelles and metabolic systems, return to normal on a time span similar to full recovery of photosynthesis. Comparison of the present data with recently published results suggests a significant role for the cytoskeleton in desiccation responses.

Desiccation tolerance in the moss Polytrichum formosum: physiological and fine-structural changes during desiccation and recovery.

This study explores basic physiological features and time relations of recovery of photosynthetic activity and CO2 uptake following rehydration of a desiccation-tolerant moss in relation to the full temporal sequence of cytological changes associated with recovery to the normal hydrated state. It seeks reconciliation of the apparently conflicting published physiological and cytological evidence on recovery from desiccation in bryophytes. Observations were made of water-stress responses and recovery using infrared gas analysis and modulated chlorophyll fluorescence, and of structural and ultrastructural changes by light and transmission electron microscopy. Net CO2 uptake fell to zero at approx. 40 % RWC, paralleling the fluorescence parameter PhiPSII at 200 micromol m(-2) s(-1) PPFD. On re-wetting the moss after 9-18 d desiccation, the initially negative net CO2 uptake became positive 10-30 min after re-wetting, restoring a net carbon balance after approx. 0.3-1 h. The parameter Fv/Fm reached approx. 80 % of its pre-desiccation value within approx. 10 min of re-wetting. In the presence of the protein-synthesis inhibitors chloramphenicol and cycloheximide, recovery of Fv/Fm (and CO2 exchange) proceeded normally in the dark, but declined rapidly in the light. Though initial recovery was rapid, both net CO2 uptake and Fv/Fm required approx. 24 h to recover completely to pre-desiccation values. The fixation protocols produced neither swelling of tissues nor plasmolysis. Thylakoids, grana and mitochondrial cristae remained intact throughout the drying-re-wetting cycle, but there were striking changes in the form of the organelles, especially the chloroplasts, which had prominent lobes and lamellar extensions in the normally hydrated state, but rounded off when desiccated, returning slowly to their normal state within approx. 24 h of re-wetting. Sub-cellular events during desiccation and re-wetting were generally similar to those seen in published data from the pteridophyte Selaginella lepidophylla. Initial recovery of respiration and photosynthesis (as of protein synthesis) is very rapid, and independent of protein synthesis, suggesting physical reactivation of systems conserved intact through desiccation and rehydration, but full recovery takes approx. 24 h. This is consistent with the cytological evidence, which shows the thylakoids and cristae remaining intact through the whole course of dehydration and rehydration. Substantial and co-ordinated changes in other cell components, which must affect spatial relationships of organelles and metabolic systems, return to normal on a time span similar to full recovery of photosynthesis. Comparison of the present data with recently published results suggests a significant role for the cytoskeleton in desiccation responses.

Bilateral Pneumothorax Induced by Tracheal Injury during Total Thyroidectomy with Modified Radical Neck Dissection - A case report -

We experienced one case of bilateral pneumothorax developed after total thyroidectomy with modified radical neck dissection in a 44-year-old male patient with thyroid carcinoma. After the conclusion of the operation, the patient was extubated after confirming recovery of consciousness and spontaneous respiration. Soon after the extubation, sudden-onset dyspnea with desaturation was developed. Rapid re-intubation was performed. Bilateral pneumothorax with severe subcutaneous emphysema was recognized on chest radiograph and successfully treated by chest tube insertion. Secondary operation was performed and tracheal injury was proved to be the source of the pneumothorax. The patient was discharged uneventfully 14 days later. (Korean J Anesthesiol 2007; 53: 399～402)

Hypoxic conformance of metabolism in primary rat hepatocytes: A model of hepatic hibernation

Following prolonged hypoxia, mammalian cells invoke adaptive mechanisms to enhance oxygen delivery and promote energy conservation. We previously reported that hepatocytes subjected to prolonged moderate hypoxia (PO2 = 20-50 mmHg for > 3 hours) demonstrated a reversible inhibition of cellular respiration with maintenance of cell viability, associated with a decrease in mitochondrial adenosine triphosphate (ATP) synthesis; acute hypoxia (similar PO2 for < 30 minutes) did not induce a similar suppression of respiration and ATP synthesis. In the current study, using an in vitro model of primary rat hepatocytes, we measured the changes in metabolic demand for ATP during hypoxic conformance, and tested whether viability is maintained by preferentially suppressing nonessential processes while sustaining processes essential for maintaining cell homeostasis. In addition, the rate of recovery of oxygen consumption and ATP concentrations following reoxygenation after prolonged and acute hypoxia/anoxia was compared. Oxygen consumption and ATP concentrations decreased during prolonged hypoxia compared with acute hypoxia. However, ouabain-inhibitable respiration did not decrease during prolonged hypoxia, indicating that membrane Na+/K+ ATPase activity, an essential process for cell viability, was maintained. In contrast, ATP-dependent glucuronidation and sulfation of acetaminophen, deemed "non-essential" processes, were decreased significantly compared with normoxic cells. After reoxygenation, cells exposed to prolonged moderate hypoxia demonstrated a more rapid recovery of respiration compared to acute hypoxia/anoxia. This "hepatic hibernation" during prolonged moderate hypoxia may represent an anticipatory adaptation that seeks to maintain cell viability while delaying or preventing the onset of lethal hypoxia, and facilitates rapid recovery after the resumption of normoxia.

Desiccation tolerance in the moss Polytrichum formosum: physiological and fine-structural changes during desiccation and recovery.

This study explores basic physiological features and time relations of recovery of photosynthetic activity and CO(2) uptake following rehydration of a desiccation-tolerant moss in relation to the full temporal sequence of cytological changes associated with recovery to the normal hydrated state. It seeks reconciliation of the apparently conflicting published physiological and cytological evidence on recovery from desiccation in bryophytes. Observations were made of water-stress responses and recovery using infrared gas analysis and modulated chlorophyll fluorescence, and of structural and ultrastructural changes by light and transmission electron microscopy. Net CO(2) uptake fell to zero at approx. 40 % RWC, paralleling the fluorescence parameter PhiPSII at 200 micromol m(-2) s(-1) PPFD. On re-wetting the moss after 9-18 d desiccation, the initially negative net CO(2) uptake became positive 10-30 min after re-wetting, restoring a net carbon balance after approx. 0.3-1 h. The parameter F(v)/F(m) reached approx. 80 % of its pre-desiccation value within approx. 10 min of re-wetting. In the presence of the protein-synthesis inhibitors chloramphenicol and cycloheximide, recovery of F(v)/F(m) (and CO(2) exchange) proceeded normally in the dark, but declined rapidly in the light. Though initial recovery was rapid, both net CO(2) uptake and F(v)/F(m) required approx. 24 h to recover completely to pre-desiccation values. The fixation protocols produced neither swelling of tissues nor plasmolysis. Thylakoids, grana and mitochondrial cristae remained intact throughout the drying-re-wetting cycle, but there were striking changes in the form of the organelles, especially the chloroplasts, which had prominent lobes and lamellar extensions in the normally hydrated state, but rounded off when desiccated, returning slowly to their normal state within approx. 24 h of re-wetting. Sub-cellular events during desiccation and re-wetting were generally similar to those seen in published data from the pteridophyte Selaginella lepidophylla. Initial recovery of respiration and photosynthesis (as of protein synthesis) is very rapid, and independent of protein synthesis, suggesting physical reactivation of systems conserved intact through desiccation and rehydration, but full recovery takes approx. 24 h. This is consistent with the cytological evidence, which shows the thylakoids and cristae remaining intact through the whole course of dehydration and rehydration. Substantial and co-ordinated changes in other cell components, which must affect spatial relationships of organelles and metabolic systems, return to normal on a time span similar to full recovery of photosynthesis. Comparison of the present data with recently published results suggests a significant role for the cytoskeleton in desiccation responses.

Physiological behavior of Scenedesmus sp. during exposure to elevated levels of Cu and Zn and after withdrawal of metal stress

A 48 h exposure of Scenedesmus sp. to sublethal concentrations of Cu (2.5 and 10 microM) and Zn (5 and 25 microM) caused a concentration-dependent inhibition of growth, photosynthesis, respiration, NO(3)(-) uptake, and nitrate reductase (EC 1.6.6.1) activity, and a reduction in protein, carbohydrate, and photosynthetic-pigment levels with a concomitant increase in intracellular levels of the test metals. After exposure, algal cells were transferred to the basal medium without the excess level of test metals, to study the recovery of various processes. The growth of the test algae had not recovered up to 12 h after transfer to the basal medium, but some physiological parameters such as photosynthesis and respiration recovered within 6 h. The quicker recovery of photosynthesis and respiration might be used as acclimatory responses as they prepare a background for the recovery of other parameters, including growth, of the test alga by generating energy, forming photosynthate, and establishing the usual catabolism to attain normal conditions. Most of the processes recovered completely or almost completely after being stressed with 2.5 microM Cu or 5 microM Zn. However, the maintenance of a relatively high level of Cu and Zn in the cells previously exposed to 10 microM Cu and 25 microM Zn slowed down the recovery of different processes, which did not fully recover even at the end of the experiment after 96 h. The present study demonstrates that a chain of metabolic events, beginning with respiration and photosynthesis and continuing with assimilation and uptake of nutrients and subsequent restoration of other metabolic processes, is involved in the recovery of the algae from Cu and Zn stress. Each studied parameter seems to play an important role in balancing the cellular homeostasis during recovery from metal stress.

Respiratory chain supercomplexes set the threshold for respiration defects in human mtDNA mutant cybrids

Mitochondrial DNA (mtDNA) mutations cause heterogeneous disorders in humans. MtDNA exists in multiple copies per cell, and mutations need to accumulate beyond a critical threshold to cause disease, because coexisting wild-type mtDNA can complement the genetic defect. A better understanding of the molecular determinants of functional complementation among mtDNA molecules could help us shedding some light on the mechanisms modulating the phenotypic expression of mtDNA mutations in mitochondrial diseases. We studied mtDNA complementation in human cells by fusing two cell lines, one containing a homoplasmic mutation in a subunit of respiratory chain complex IV, COX I, and the other a distinct homoplasmic mutation in a subunit of complex III, cytochrome b. Upon cell fusion, respiration is recovered in hybrids cells, indicating that mitochondria fuse and exchange genetic and protein materials. Mitochondrial functional complementation occurs frequently, but with variable efficiency. We have investigated by native gel electrophoresis the molecular organization of the mitochondrial respiratory chain in complementing hybrid cells. We show that the recovery of mitochondrial respiration correlates with the presence of supramolecular structures (supercomplexes) containing complexes I, III and IV. We suggest that critical amounts of complexes III or IV are required in order for supercomplexes to form and provide mitochondrial functional complementation. From these findings, supercomplex assembly emerges as a necessary step for respiration, and its defect sets the threshold for respiratory impairment in mtDNA mutant cells.

Anaesthetic management of a case of neonatal tetanus undergoing laparotomy for intestinal obstruction

Aim: To highlight the importance of committed efforts in pre- and postoperative anaesthetic management of very ill neonates. Case Report: General anaesthesia was administered for laparotomy in a five day old baby boy with intestinal obstruction and neonatal tetanus, who had an anaesthetic risk of (ASA) 4E. Ante-natal care and delivery were carried out by a traditional birth attendant. He was resuscitated with 4.3% dextrose in 0.18 saline until stable pulse, blood pressure and urine output were achieved over a six hour period. Antibiotics and anti-tetanus therapy were started in the ward. The patient was given a diazepam based general anaesthesia with muscle relaxation and manually ventilated with 70% oxygen in air. Oxygen saturation, pulse, temperature and blood pressure were maintained at stable levels during the operation which lasted two and half hours. Early recovery of spontaneous respiration was encouraged, in the absence of ideal postoperative respiratory support. Manual respiratory assistance was continued for another 5hrs postoperatively before spontaneous respiration was judged adequate. Supplementary oxygen via the nasal catheter was continued until his discharge to the ward on the 23rd day. Conclusion: When surgery is the best management option, the patient should not be too ill for it. It is, however, important that the best achievable clinical condition within the safe moments be realized. Keywords: neonate, hernia, tetanus, anaesthesia Orient Journal of Medicine Vol. 17(3&4) 2005: 1-6

Clinical features and neurophysiological follow-up in a case of Brown-Vialetto-Van Laere syndrome

Brown-Vialetto-Van Laere syndrome is a rare disease of unknown origin commonly considered as part of the large group of motor neuron diseases. The course is quite variable: it may be quickly fatal or protracted, with relapsing phases followed by periods of arrest and even partial improvement. We describe a case of Brown-Vialetto-Van Laere syndrome with strong family history for sensorineural hearing impairment. The patient came to our medical attention for severe respiratory failure and leg weakness. The clinical conditions partially improved with recovery of spontaneous respiration and mild increase in muscle strength. The neurophysiological studies performed on our patient showed evidence of nerve damage with subsequent improvement. Our study raises the possibility that the disorder is due to primary nerve damage, which can better justify the intermittent course of the disease, the partial clinical regression and the neurophysiological improvement, never detected in typical motor neuron disorders.

Comparison of Tramadol and Meperidine for Pain Relief after Tonsillectomy in Children

Background: Pain is one of the major problem regarding quality of life in children undergoing tonsillectomy. Preemptive analgesia by medicine given before commencement of surgery is a new recommended for relief of pain during and after operation. We compared intra-and postoperative analgesic and recovery characteristics of tramadol, meperidine with placebo given at induction of anesthesia in 60 children undergoing tonsillectomy with or without adenoidectomy. Methods: Sixty children (ASA Ior II) 4-7 years old undergoing tonsillectomy with or without adenoidectomy were randomly assigned to receive either saline 0.02 ml/kg (group 1, n = 20), tramadol 2 mg/kg (group 2, n = 20) or meperidine 1 mg/kg (group 3, n = 20) at induction of anesthesia. Thiopental sodium (5 mg/kg) and rocuronium (0.6 mg/kg) were used for the induction of anesthesia, and it was maintained with sevoflurane in / (50/50) via an endotracheal tube. Pain assessment was done by facial pain scale. Agitation scores, time to recovery of spontaneous respiration and the incidence of postoperative nausea and vomiting were assessed. Heart rate and mean arterial pressure were recorded. Results: Facial pain scale scores were increased in group 1 and group 2 at 10 and 20 min after tonsillectomy in recovery room. There was no difference for agitation scores in the three groups. Intraoperative mean arterial pressure (15 min) were found to be higher in group 1 and group 2. The time to recovery of spontaneous respiration was delayed in group 3 compared with group 1 and group 2. The incidence of nausea and vomiting was not statistically differed among groups. Conclusions: Meperidine was more effective for pain relief than tramadol, even though recovery of spontaneous respiration was delayed in meperidine group.

BH4 peptide derivative from Bcl-xL attenuates ischemia/reperfusion injury thorough anti-apoptotic mechanism in rat hearts

To prevent apoptosis is thought to be promising for myocardial protection in cardiac surgery. Recently, we showed that BH4 domain of Bcl-xL is essential for the prevention of apoptosis, and that BH4 fused to HIV TAT protein (TAT-BH4) prevented apoptotic cell death. Then, we hypothesized TAT-BH4 may attenuate ischemia/reperfusion injury in rat hearts. The isolated rat hearts in the TAT-BH4 preconditioning group (BH4 group, n=8) or control group (C group, n=8) were subjected to warm ischemia (37 degrees C) for 30 min followed by 60 min of reperfusion using Langendorff perfusion system. Left ventricular developed pressure and maximum dP/dt after reperfusion were significantly improved in the BH4 group than those in the C group (P<0.01). Recovery of mitochondrial respiration was significantly better in the BH4 group (P<0.05). Moreover, expression of caspase-3 and TUNEL-positive myocardium were decreased in the BH4 group than those in the C group. These results demonstrated that TAT-BH4 attenuates myocardial ischemia/reperfusion injury through preventing myocardial apoptosis. Thus, TAT-BH4 may be a novel therapeutic agent for myocardial protection in cardiac surgery.

Difficult Tracheal Intubation Due to Lingual Tonsillar Hypertrophy: A case report

Lingual tonsillar hypertrophy (LTH) is a rare and dangerous condition in the management of the upper airway. It is not detectable from the history or on routine preoperative physical examination. Enlarged lingual tonsils can cause posterior displacement. A 56 year old man was scheduled for emergency laryngeal microscopic surgery for the removal of a throat foreign body. After the induction of general anesthesia, intubation with a rigid laryngoscope was impossible due to LTH. After recovery of self respiration, the endotracheal tube intubation was possible by the combined use of a laryngoscope, Magil forceps and fiberoptic bronchoscope.

General anaesthesia in a patient with motor neuron disease

EDITOR: Motor neuron disease is a degenerative disorder of the ganglia in the anterior horn of spinal cord and spinal pyramidal tracts. An example is amyotrophic lateral sclerosis [1]. Motor neurone disease involves initial atrophy of respiratory muscles. In the latter parts of the disease, respiratory weakness occurs with respiratory insufficiency and failure of breathing leading to death [1,2]. Respiratory complications are common and a cause for concern in the management of patients with motor neurone disease. The perioperative pulmonary complication rate has been found to be significantly higher after upper abdominal surgery in patients with muscular disability and complications should be anticipated [3]. It is well documented that patients with motor neurone disease can have problems when swallowing. The risk of aspiration and airway obstruction with the risk of regurgitation has to be regarded as high [2,4,5]. We report a 56-yr-old man, diagnosed with pancreatic carcinoma and amyotrophic lateral sclerosis scheduled for elective Whipple's surgery. At preoperative evaluation, the patient reported difficulties with breathing while talking, and described swallowing problems for the preceding 5 weeks with weakness of lower and upper extremities. Blood pressure was 130/85 mmHg, and electrocardiogram (ECG) and chest radiograph showed no abnormalities. Spirometry was attempted prior to operation, but because of exhaustion of the patient this test had to be stopped. Anaesthetic management was planned with the aim of minimizing the duration of general anaesthesia and its effects on the respiratory centre, chemoreceptors and respiratory muscles [6]. Thoracic epidural anaesthesia was considered, but after discussion of risks and benefits, the patient refused consent for regional anaesthesia. After a 5-h operation, the patient was transferred intubated to our postanaesthesia care unit. When the patient recovered consciousness 8 h after the end of operation, he was ventilated with continuous positive airway pressure (CPAP) and was extubated under controlled conditions 5 h later with a normal breathing pattern and with no signs of respiratory exhaustion. Unfortunately, he had to undergo a second surgical procedure 3 h after extubation. An uncomplicated surgical revision lasting 3 h was performed. After recovery from muscular relaxation as indicated by a train of four ratio of 0.88, PCO2 of 41 mmHg and SPO2 of 97%, an early extubation with no complications was performed. In the postanaesthesia care unit, respiratory insufficiency developed 3 h later, despite an augmented spontaneous breathing pattern, heralded by hypercapnia (PCO2 of 63.4 mmHg). Two days later, the patient was re-intubated because of respiratory exhaustion with a PaCO2 at about 130 mmHg. Tracheostomy was performed 2 days later under general anaesthesia. Thereafter, the patient was transferred awake and breathing with CPAP to the neurological intensive care unit. Slight breathing improvements were observed during subsequent weaning. However, the patient was able to sustain only very brief periods without respiratory support. One month after surgery, the patient was transferred to a secondary care facility, still requiring respiratory support. After the first surgical procedure, we observed almost full recovery of respiration with no necessity for further respiratory support. After a second general anaesthetic procedure within a short period of time, worsening respiratory distress and exhaustion necessitated tracheostomy and implementation of respiratory support. Weaning from respiratory support was not successful during the month the patient spent at our hospital. We agree with the previous reports stipulating that neuromuscular monitoring is essential in administrating non-depolarizing neuromuscular blocking agents to patients with motor neurone disease for general surgery [5,7]. Depolarizing muscle relaxants, such as succinylcholine, are not recommended because of reported rhabdomyolysis and hyperkalemia from denervated muscles, possibly leading to ventricular arrhythmias or fibrillation [8]. As in our case, recovery of train of four was reported from low-dose cisatracurium, which may be a good choice for muscle relaxation in these patients and good respiratory compliance was perceived after extubation. Based upon the present case, we conclude that anaesthesia for major surgery using low doses of cisatracurium and propofol is possible in patients with motor neurone disease. However, repeated surgery in such patients may lead to a considerable increase in respiratory complications. In concordance with previous reports, we suggest that spirometry should be performed prior to major surgery, whenever possible, and recommend the use of neuromuscular monitoring when planning general anaesthesia in these patients [6]. B. Moser P. Lirk M. Lechner M. Gottardis Department of Anaesthesiology and Critical Care Medicine; University of Innsbruck; Innsbruck, Austria

Control of respiration by nitric oxide in Keilin-Hartree particles, mitochondria and SH-SY5Y neuroblastoma cells.

The pattern of cytochrome c oxidase inhibition by nitric oxide (NO) was investigated polarographically using Keilin-Hartree particles, mitochondria and human neuroblastoma cells. NO reacts with purified cytochrome c oxidase forming either a nitrosyl- or a nitrite-inhibited derivative, displaying distinct kinetics and light sensitivity of respiration recovery in the absence of free NO. Keilin-Hartree particles or cells, respiring either on endogenous substrates alone or in the presence of ascorbate, as well as state 3 and state 4 mitochondria respiring on glutamate and malate, displayed the rapid recovery characteristic of the nitrite derivative. All systems, when respiring in the presence of tetramethyl-p-phenylenediamine, were characterised by the slower, light-sensitive recovery typical of the nitrosyl derivative. Together the results suggest that the reaction of NO with cytochrome c oxidase in situ follows two alternative inhibition pathways, depending on the electron flux through the respiratory chain.

Responses of Microbial Activity and Decomposer Organisms to Contamination in Microcosms Containing Coniferous Forest Soil

Soil respiration from microcosms contaminated with pentachlorophenol, 2-ethanolhexanoate, creosote, CuSO 4, and benomyl was measured in order to evaluate usefulness of soil microcosms and microbial respiration rate monitoring as a toxicity test in soils with high organic matter content. Coniferous forest soil and its organisms were used as test objects. In addition, how a short-term low temperature period including frost affects respiration dynamics in stressed soils was studied, i.e., whether contaminants reduce resistance of the community to other (also natural) stresses. In addition, at the end of the experiment, effects of contaminants on faunal and microbial community structures were analyzed. Soil respiration measurements from the microcosms appeared to be a sensitive parameter for testing community-level effects of chemicals in the soil with high organic matter content. An 84-day exposure had acute effects, long-term effects, delaying effects, and total recovery of community respiration. Direct negative and indirect positive effects of chemical contamination on the community of soil organisms were found. Responses to contamination of soil respiration rate and structure of the soil community were parallel. Addition of pentachlorophenol, 2-ethanolhexane, and Cu into the soil reduced frost resistance of the decomposer community. It was concluded that soil respiration monitoring of artificially contaminated soil microcosms seems to be a useful tool for testing community-level toxic effects of chemicals.