Accidental deep hypothermia with cardiac arrest. Prompt complete recovery after rewarming by extracorporeal circulation. Case report

BACKGROUND: Deep accidental hypothermia (core temperature <28 degrees C) is an uncommon medical emergency requiring rapid active core rewarming. Extracorporeal circulation has become the treatment of choice for deep hypothermic patients with cardiac arrest. CASE REPORT: We report on a 30-year-old patient who suffered from deep accidental hypothermia (core temperature 24.8 degrees C) and cardiac arrest by prolonged exposure to a cold urban environment as a consequence of severe ethylalcohol intoxication. The rewarming with the aid of extracorporeal circulation was initiated shortly after his arrival at the hospital. External cardiac massage was maintained until full ECC fl ow was established. The patient was weaned from extracorporeal circulation after 157 min, awaked 4 hours later and consequently extubated within 16 hours after rewarming with no neurological impairment. At 3-week follow-up, the patient was fully re-integrated in his work and personal life. CONCLUSION: This case demonstrates the excellent prognosis of a young victim in the case of deep accidental hypothermia with cardiac arrest, provided that deep hypothermia precedes the cardiac arrest and rewarming by extracorporeal circulation is immediately applied. Simultaneous ethyl alcohol intoxication can be considered a protective factor improving the patient's outcome. Complete recovery was achieved within 24 hours after the accident.     

Carbamazepine produces nonspecific effects on cocaine self-administration in rats.

Anecdotal evidence in humans suggest that carbamazepine suppresses cocaine-induced rush and craving. Such claims are unsupported in controlled trials using a placebo control. In the present study, rats were trained to self-administer i.v. cocaine in daily 2-hr sessions in which every tenth lever press delivered 1 mg/kg cocaine. After responding was stable, they were injected before each session with the vehicle for 2 days followed by carbamazepine for 2 days. At a 7 mg/kg dose, carbamazepine was without effect, whereas 15 mg/kg suppressed responding for cocaine only on the second (day 4) day of carbamazepine treatment. With 4 consecutive days of treatment, carbamazepine (15 mg/kg) reduced cocaine-maintained responding slightly, but significantly. In another group of animals trained to lever-press for food reinforcement, carbamazepine (15 mg/kg) also significantly decreased the rate of responding, suggesting that the suppression of responding was not specific to cocaine-reinforced behavior.     

Methanol Intoxication Victims are Suitable Donors for Corneal Transplantation

Purpose. To evaluate the outcome of corneal transplantation and the feasibility of tissue donation from donors with methanol intoxication. Methods. Four corneas from two methanol intoxication victims were procured and transplanted in four patients at our medical center. The outcome and graft survival were evaluated. Results. The recipients were between 12 and 49 years of age. Indications for transplantation were keratoconus (two patients), post-traumatic corneal perforation (one patient) and alkaline burn (one patient). The follow-up period ranged between 12 and 60 months. All grafts remained clear, and the postoperative visual acuity was 20/30 in keratoconus patients and 20/60 in others. Conclusions. The methanol intoxication victims appear to be suitable donors for corneal transplantation. To the best of our knowledge, this is the first study to report successful corneal transplantation from donors with methanol intoxication.     

Development of antidotes for sodium monofluoroacetate (1080)

Baits containing sodium monofluoroacetate (1080) are commonly used in New Zealand during feral pest control operations. However, each year, a number of domestic dogs are unintentionally killed during these control operations, and a suitable antidote to 1080 intoxication is required. The primary toxic mechanism of 1080 is well known. However, as with other pathologies where energy deprivation is the main effect of intoxication, the cascade of effects that arises from this primary mechanism is complex. At present, putative antidotes for 1080 are generally unable to address the primary mechanism of intoxication but such agents may be able to control the cascade of secondary effects, which can result during intoxication. Part of the reason for this is that targeting the cascade can provide a longer window of time for antidote success. We have undertaken studies that identified some of the central nervous system (CNS) and systemic pathophysiological cascades caused by 1080 intoxication. Using this information we designed antidotes, on the basis of preventing different steps in this cascade. In the chicken model targeting systemic changes, in particular reducing effects of nitric oxide derivatives generated in cardiac muscle, proved successful in reducing fatality associated with 1080. In rats and sheep, targeting the CNS with a number of compounds including: glutamate; calcium and dopamine antagonists; gamma amino butyric acid agonists, and astressin-like compounds reduced fatalaties. However, to be successful in the rat and sheep model a given antidote needed to move quickly from systemic circulation across the blood brain barrier and into the CNS. The work also suggests ways in which specific biomarkers of 1080 exposure may be developed with respect to different species.     

The content of glycogen and its fractions in human hepatocytes in traumatic disease

A cytofluorometric study was made of the total glycogen and its of fractions in liver cells of patients with hard mechanic trauma with or without intoxication. For studying glycogen dynamics in the course of traumatic illness, the aspiration biopsy material was obtained (30 patients) using repeated liver biopsy of one and the same patient. The total glycogen was found to change insignificantly in liver cells of patients with traumatic illness, both under favourable conditions and with intoxication, and at the normal level. The labile glycogen fraction in liver cells of patients with traumatic illness without intoxication is contained almost at the normal level (80-95%) of the total glycogen and is not changed for a long time. At that time the relative content of the labile glycogen fraction decreases appreciably in some cases to 45-50% due to intoxication development. A relative content of the labile glycogen fraction in hepatocytes with hard mechanical intoxication correlates well with the degree of intoxication. This makes hepatocyte glycogen microfluorometry a diagnostic tool in measuring the functional state of liver in the course of intoxication.     

A respiratory venous chemoreceptor in the young puppy.

An extracorporeal venovenous shunt system utilizing a membrane oxygenator to alter venous blood gases was used to study the regulation of ventilation in 28 newborn and 4 adult dogs. There was no effect of the extracorporeal circuit per se (without the oxygenator in the system) on essential cardiovascular or respiratory function. When the puppies were placed on the extracorporeal circuit with the oxygenator in the system to effect changes in mixed venous blood gas composition there was a significant increase in venous P02 (Pv02), a decrease in venous Pco2 (Pvco2), a rise in venous pH (PHv), and a marked fall in minute ventilation (VE). There were no significant changes in cardiovascular function or arterial blood gases to account for the depression of ventilation. Acute changes in Pvo2 produced appropriate directional changes of VE under conditions where other arterial and venous blood gases were held constant. At a low Pvco2/Paco2 ratio, ventilation was depressed compared to those conditions with a high ratio. At any Pvc02/Paco2 ratio, ventilation could be depressed by raising the Pvo2. In adult animals ventilation could not be altered by changing venous blood gases. These experiments support the existence of a respiratory chemoreceptor sensitive to both PO2 and PCO2 in the prepulmonary or venous circulation of the newborn animal.     

Changes of cerebral gamma glutamyltransferase activities after treatment with exogenous inducers

The activity of gamma-glutamyltransferase localized in isolated brain synaptic membranes- and microvessels-enriched fractions was assayed after treatment of rats with either phenobarbital or ethanol. Phenobarbital increased the activity of gamma-glutamyltransferase in microvessels, without alteration of synaptic membranes activity. An increase of enzyme activity was also obtained after a chronic intoxication with ethanol. These results suggest that the isoform of gamma-glutamyltransferase localized in brain microvessels may respond to exogenous inducers.     

The Rabbit Blood-shunt Model for the Study of Acute and Late Sequelae of Subarachnoid Hemorrhage: Technical Aspects

Early brain injury and delayed cerebral vasospasm both contribute to unfavorable outcomes after subarachnoid hemorrhage (SAH). Reproducible and controllable animal models that simulate both conditions are presently uncommon. Therefore, new models are needed in order to mimic human pathophysiological conditions resulting from SAH.This report describes the technical nuances of a rabbit blood-shunt SAH model that enables control of intracerebral pressure (ICP). An extracorporeal shunt is placed between the arterial system and the subarachnoid space, which enables examiner-independent SAH in a closed cranium. Step-by-step procedural instructions and necessary equipment are described, as well as technical considerations to produce the model with minimal mortality and morbidity. Important details required for successful surgical creation of this robust, simple and consistent ICP-controlled SAH rabbit model are described.     

Solid-vapor interactions: Influence of environmental conditions on the dehydration of carbamazepine dihydrate

The goal of this research was a phenomenological study of the effect of environmental factors on the dehydration behavior of carbamazepine dihydrate. Dehydration experiments were performed in an automated vapor sorption apparatus under a variety of conditions, and weight loss was monitored as a function of time. In addition to lattice water, carbamazepine dihydrate contained a significant amount of physically bound water. Based on the kinetics of water loss, it was possible to differentiate between the removal of physically bound water and the lattice water. The activation energy for the 2 processes was 44 and 88 kJ/mol, respectively. As expected, the dehydration rate of carbamazepine dihydrate decreased with an increase in water vapor pressure. While dehydration at 0% relative humidity (RH) resulted in an amorphous anhydrate, the crystallinity of the anhydrate increased as a function of the RH of dehydration. A method was developed for in situ crystallinity determination of the anhydrate formed. Dehydration in the presence of the ethanol vapor was a 2-step process, and the fraction dehydrated at each step was a function of the ethanol vapor pressure. We hypothesize the formation of an intermediate lower hydrate phase with unknown water stoichiometry. An increase in the ethanol vapor pressure first led to a decrease in the dehydration rate followed by an increase. In summary, the dehydration behavior of carbamazepine dihydrate was evaluated at different vapor pressures of water and ethanol. Using the water sorption apparatus, it was possible to (1) differentiate between the removal of physically bound and lattice water, and (2) develop a method for quantifying, in situ, the crystallinity of the product (anhydrate) phase.     

Effect of Sonne shigella endotoxin on cholinergic regulation of intestinal circulation]

A method of extracorporeal autoperfusion and resistography of the intestinal vessels and synchronous multichannal recording the systemic blood circulation were applied to the study of the influence of the Sh. sonnei endotoxin on the cholinergic regulation of the cardiovascular system in Macacus rhesus. It was shown that development of intoxication was accompanied by the changes in the cholinergic regulation of the intestinal and systemic circulation leading to its disturbance. Possibly affection of the cholinergic control structures and disturbances of the circulation determined the development and the course of the infectious process.     

Synthesis/biological evaluation of hydroxamic acids and their prodrugs as inhibitors for Botulinum neurotoxin A light chain

Botulinum neurotoxin A (BoNT/A) is the most potent toxin known. Unfortunately, it is also a potential bioweapon in terrorism, which is without an approved therapeutic treatment once cellular intoxication takes place. Previously, we reported how hydroxamic acid prodrug carbamates increased cellular uptake, which translated to successful inhibition of this neurotoxin. Building upon this research, we detail BoNT/A protease molecular modeling studies accompanied by the construction of small library of hydroxamic acids based on 2,4-dichlorocinnamic hydroxamic acid scaffold and their carbamate prodrug derivatization along with the evaluation of these molecules in both enzymatic and cellular models.     

Carbamazepine as a Novel Small Molecule Corrector of Trafficking-impaired ATP-sensitive Potassium Channels Identified in Congenital Hyperinsulinism

ATP-sensitive potassium (K_ATP) channels consisting of sulfonylurea receptor 1 (SUR1) and the potassium channel Kir6.2 play a key role in insulin secretion by coupling metabolic signals to β-cell membrane potential. Mutations in SUR1 and Kir6.2 that impair channel trafficking to the cell surface lead to loss of channel function and congenital hyperinsulinism. We report that carbamazepine, an anticonvulsant, corrects the trafficking defects of mutant K_ATP channels previously identified in congenital hyperinsulinism. Strikingly, of the 19 SUR1 mutations examined, only those located in the first transmembrane domain of SUR1 responded to the drug. We show that unlike that reported for several other protein misfolding diseases, carbamazepine did not correct K_ATP channel trafficking defects by activating autophagy; rather, it directly improved the biogenesis efficiency of mutant channels along the secretory pathway. In addition to its effect on channel trafficking, carbamazepine also inhibited K_ATP channel activity. Upon subsequent removal of carbamazepine, however, the function of rescued channels was recovered. Importantly, combination of the K_ATP channel opener diazoxide and carbamazepine led to enhanced mutant channel function without carbamazepine washout. The corrector effect of carbamazepine on mutant K_ATP channels was also demonstrated in rat and human β-cells with an accompanying increase in channel activity. Our findings identify carbamazepine as a novel small molecule corrector that may be used to restore K_ATP channel expression and function in a subset of congenital hyperinsulinism patients.     

Percutaneous cholecystolithotomy

A percutaneous method was used to remove stones from otherwise normal gall bladders, as assessed by cholecystography and ultrasonography. The procedure was performed in a single stage under general anaesthesia, adopting the method and instruments used for one stage percutaneous nephrolithotomy. A Foley catheter was left in the gall bladder and the system checked with contrast at 10 days to ensure free drainage and exclude residual calculi. Seven out of eight patients had a successful percutaneous cholecystolithotomy. An adequate track could not be secured in one man; he had an uneventful cholecystectomy under the same anaesthetic. Follow up at three months of the seven patients showed no calculi and no complications.Percutaneous cholecystolithotomy may prove complementary to extracorporeal shockwave lithotripsy in patients in whom there is difficulty focusing the shock waves on the gall bladder or who have had incomplete disintegration of stones.     

The Kolff-Merrill artificial kidney; clinical application in acute renal insufficiency

Acute renal insufficiency is often called "lower nephron nephrosis." Its recognition, its prognostic significance, and its therapy by conservative measures are receiving increasing clinical emphasis. The mortality rate in this complicated syndrome still remains unduly high. One method of therapy of anuric patients whose lives are in jeopardy because of fulminating uremia or critical potassium intoxication is use of an artificial kidney to "purify" the blood stream by means of extracorporeal dialysis.The author describes clinical (and laboratory) experience with ten such dialyzed patients, eight of whom presented the classical picture of acute renal insufficiency. Four died, one from unrecognized coronary occlusion, another from antecedent, overwhelming peritonitis. Two other patients with chronic kidney disorders received no benefit from dialysis and died of renal disease. Good biochemical and clinical response was brought about in six cases of lower nephron nephrosis. Presumably, these six patients would have died had they not been subjected to artificial dialysis.     

Selective removal of human serum amyloid P component from rat blood by use of an immunoaffinity membrane in an extracorporeal circulation system

We examined the suitability of an immunoaffinity membrane (IAM) bearing specific antibody as a ligand for removing human serum amyloid P component (hSAP) from blood passed through a simple extracorporeal circulation system established in rats. The specific antibody was the most effective of the various ligands tested for removing hSAP from human blood. To determine the value of the hSAP in human or rat plasma, we also developed a simple ELISA. In the rat extracorporeal circulation system, the hSAP level in the inlet blood to the IAM module decreased to 49% of the initial concentration within 60 min. In contrast, the hSAP remained at the initial concentration throughout the study in the module without the IAM. The use of this extracorporeal circulation system in this case allows preclinical evaluation of the ex vivo removal of a human plasma component in an animal model. Biocompatibility of the IAM was also examined. No change in blood cell counts or activation of the coagulation system occurred after contact with the IAM. Non-specific adsorption was not observed, since there was no statistically significant difference in IgG, complement C3, or albumin level between the pre- and post-treatment with this module. The immunological effects of the IAM were also examined using this system. Four weeks after the termination of the extracorporeal circulation, the rats examined showed no detectable antibody titer to the ligand.     

Possible influence of cell walls upon ion concentrations at plasma membrane surfaces. Toward a comprehensive view of cell-surface electrical effects upon ion uptake, intoxication, and amelioration

Plant uptake of ions, intoxication by ions, and the alleviation of intoxication by other ions often correlate poorly with ion concentrations in the rooting medium. By contrast, uptake, intoxication, and alleviation correlate well with ion concentrations at the plasma membrane (PM) surface computed as though the PM were bathed directly in the rooting medium with no effect from the cell wall (CW). According to two separate lines of analysis, a close association of CWs and PMs results in a slight increase in cation concentrations and a slight decrease in anion concentrations at the PM surface compared with concentrations when the CW is separated or has no effect. Although slightly different, the ion concentrations at the PM surface computed with and without close association with the CW are highly correlated. Altogether, the CW would appear to have a small effect upon ion uptake by the PM or upon intoxication or alleviation of intoxication originating at the PM surface. These analyses have been enabled by the recent evaluation of parameters required for the electrostatic models (Gouy-Chapman-Stern and Donnan-plus-binding) used to compute electrical potentials and ion concentrations in CWs and at PM surfaces.     

Determination of carbamazepine and carbamazepine 10,11-epoxide in human plasma by tandem liquid chromatography-mass spectrometry with electrospray ionisation

A sensitive method for the determination of carbamazepine and carbamazepine 10,11-epoxide in plasma is described, using high-performance liquid chromatographic separation with tandem mass spectrometry. Samples were purified using liquid-liquid extraction and separated on a Phenomenex Luna C18 5 microm. 150 x 2 mm column with a mobile phase consisting of acetonitrile, methanol and formic acid (0.1%) (10:70:20, v/v). Detection was performed by a Micromass Quattro Ultima mass spectrometer in the MRM mode (LC-MS-MS) using electro spray ionisation (ESI+), monitoring the transition of the protonated molecular ion for carbamazepine at m/z 237.05 and carbamazepine 10,11-epoxide at m/z 253.09 to the predominant ions of m/z 194.09 and 180.04, respectively. The mean recovery was 95% for carbamazepine and 101% for carbamazepine 10,11-epoxide, with a lower limit of quantification of 0.722 ng/ml for carbamazepine and 5.15 ng/ml for carbamazepine 10,11-epoxide, when using 0.5 ml plasma. This high-throughput method was used to quantify 230 samples per day, and is sufficiently sensitive to be employed in pharmacokinetic studies.     

Interrelation of delta-aminolevulinic acid and brain myelin proteins as affected by benzene and lead

An experimental model of subacute lead and benzene intoxication was induced in rabbits. It increased significantly delta-aminolevulinic acid (14C-ALA) incorporation into CNS myelin. ALA stably fixes on myelin proteins, especially Wolfgram proteins. In spite of this about one half of ALA incorporated into myelin linked with its basic proteins. Lead and benzene intoxication cause changes in the proportion of the basic fractions of myelin proteins. The amount of basic proteins increases, while the amount of proteolipid and Wolfgram proteins decreases. Lead and especially benzene intoxication decreases exogenous ALA insertion into basic proteins and proteolipid proteins, with ALA fixation on Wolfgram proteins remaining unchanged.     

Prolonged delirium without anticholinergic signs following amitriptyline overdose.

In a case of acute intoxication with a tricyclic antidepressant (amitriptyline) delirium was prolonged without there being prominent peripheral anticholinergic or electrocardiographic signs. Administration of physostigmine, repeated when necessary, reversed the delirium.