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Therapeutic hypothermia has been shown to improve outcome in comatose survivors after cardiac arrest of cardiac origin. After the clinical implementation of this novel treatment, several international web-based registries were opened to facilitate the prospective collection of patient treatment data. The aim was to evaluate the actual use of hypothermia in clinical practice, safety aspects, resource utilization, and outcome in large cohorts of patients. There are two published studies from two separate registries, including 2205 cardiac arrest patients in 39 different sites, of whom 869 (39%) were treated with induced hypothermia. Another registry, The Hypothermia Registry, includes 1108 patients from 37 sites in six European countries and one center in the United States; a large majority, or 952 patients (86%), were treated with hypothermia. The three registries have different strengths and weaknesses, but the clinical outcome compares well with that of the two randomized trials. Our conclusions are that hypothermia is feasible to implement, that it seems reasonably safe, and that the outcome compares well with previous reports. We also conclude that the treatment with hypothermia after cardiac arrest is more widely applied than what is strictly evidence based.

Three young men were trapped in a car at the bottom of a canal at two meters depth, after losing control of their vehicle. They were brought up by rescue divers and found in cardiac arrest. One of three patients had return of spontaneous circulation (ROSC), at 47 min after the accident. This sole survivor had the longest submersion time of the three and he received continued mechanical chest compressions during transportation to the hospital. His temperature at admission was 26.9 degrees C, he was rewarmed to 33 degrees C and kept there for 24 h, followed by continued rewarming to normothermia. On day three, he woke up from coma and was discharged from the intensive care unit after one week. At follow-up six months later, he had a complete cerebral recovery but still had myoclonic twitches in the lower extremities. A mechanical device facilitates chest compressions during transportation and may be beneficial as a bridge to final treatment in the hospital. We recommend that comatose patients after submersion, accidental hypothermia and cardiac arrest are treated with mild hypothermia for 12-24 h.

Background: Patients who survive after suicidal hanging attempts suffer from transient brain ischaemia. Morbidity and mortality is high, and no specific therapy is available. Hypothermia attenuates ischaemic brain damage and has become standard care in comatose survivors of cardiac arrest; therapeutic hypothermia may thus be useful for near-hanging victims as well., Objectives: To perform a literature review on outcome and outcome predictors after near-hanging. To make a retrospective chart review on treatment and outcome of near-hanging victims in two Swedish intensive care units during a 4-year period (2003-2006)., Methods: The literature review was conducted as a Medline search. Study patients were identified and data retrieved from the intensive care units' medical records. The primary outcome measure was neurological function at discharge., Results: No randomised, controlled trials were found in the Medline search. Thirteen patients could be identified and were included in the study, all were in coma and three had suffered cardiac arrest. Outcome was good in six of eight patients treated with hypothermia, as compared to three of five patients who were not. All three patients with cardiac arrest received hypothermia treatment and outcome was good in one., Conclusion: No randomised, controlled trial for treatment of near-hanging victims has been published. No conclusions could be drawn regarding treatment effects of hypothermia in this survey, but in the absence of better evidence, it seems reasonable to consider hypothermia treatment in all comatose near-hanging victims.

Aim: This trial evaluated the potential for improving glycaemic control by intensifying a conventional twice-daily therapy with premixed human insulin (HI) to a thrice-daily regimen using premixed formulations of biphasic insulin aspart (BIAsp) in patients with type 1 or type 2 diabetes., Methods: This was a multicentre, open-label, parallel group trial. After a 4-week run-in period, patients were randomized 1 : 1 to 16 weeks of treatment. A total of 748 patients were screened, 664 were exposed to trial drug and 604 completed the trial., Results: Haemoglobin A(1c), the primary efficacy endpoint, was shown to be significantly lower for the BIAsp treatment group compared with the biphasic HI (BHI) 30 group [estimated mean difference: -0.32, 95% confidence interval (CI) (-0.48; -0.16), p = 0.0001]. The average blood glucose level was significantly lower in the BIAsp group [estimated mean difference: -0.79, 95% CI (-1.17; -0.40), p = 0.0001]. There were few major hypoglycaemic episodes, 11 in the BIAsp group and 7 in the BHI 30 group. Although intensification of insulin therapy with BIAsp three times a day was associated with a higher risk of minor hypoglycaemia (relative risk = 1.58, p = 0.0038), the overall rate of minor hypoglycaemia remained low with both the BIAsp and the BHI treatments (13.1 vs. 8.3 episodes/patient year respectively). Overall safety and patient satisfaction were similar with the two insulin therapies., Conclusions: This trial confirmed that a thrice-daily BIAsp regimen can safely be used to intensify treatment for patients inadequately controlled on twice-daily BHI. A treat-to-target trial is required to explore the full potential of the BIAsp regimens and evaluate their use as a viable alternative to intensification with a basal-bolus regimen.

Objective: To evaluate the use of continuous amplitude-integrated EEG (aEEG) as a prognostic tool for survival and neurological outcome in cardiac arrest patients treated with hypothermia., Design: Prospective, observational study., Setting: Multidisciplinary intensive care unit in a university hospital., Intervention: Comatose survivors of cardiac arrest were treated with induced hypothermia for 24 h. An aEEG recording was initiated upon arrival at the ICU and continued until the patient regained consciousness or, if the patient remained in coma, no longer than 120 h. The aEEG recording was not available to the ICU physician, and the aEEG tracings were interpreted by a neurophysiologist with no knowledge of the patient's clinical status. Only clinically visible seizures were treated., Measurements and Results: Thirty-four consecutive hypothermia-treated cardiac arrest survivors were included. At normothermia (mean 37 h after cardiac arrest), the aEEG pattern was discriminative for outcome. All 20 patients with a continuous aEEG at this time regained consciousness, whereas 14 patients with pathological aEEG patterns (flat, suppression-burst or status epilepticus) did not regain consciousness and died in hospital. Patients were evaluated neurologically upon discharge from the ICU and after 6 months, using the Cerebral Performance Category (CPC) scale. Eighteen patients were alive with a good cerebral outcome (CPC 1--2) at 6-month follow-up., Conclusion: A continuous aEEG pattern at the time of normothermia was discriminative for regaining consciousness. aEEG is an easily applied method in the ICU setting.

A large proportion of deaths in the Western World are caused by ischaemic heart disease. Among these patients a majority die outside hospital due to sudden cardiac death. The prognosis among these patients is in general, poor. However, a significant proportion are admitted to a hospital ward alive. The proportion of patients who survive the hospital phase of an out of hospital cardiac arrest varies considerably. Several treatment strategies are applicable during the post resuscitation care phase, but the level of evidence is weak for most of them. Four treatments are recommended for selected patients based on relatively good clinical evidence: therapeutic hypothermia, beta-blockers, coronary artery bypass grafting, and an implantable cardioverter defibrillator. The patient's cerebral function might influence implementation of the latter two alternatives. There is some evidence for revascularisation treatment in patients with suspected myocardial infarction. On pathophysiological grounds, an early coronary angiogram is a reasonable alternative. Further randomised clinical trials of other post resuscitation therapies are essential.

Insulin aspart has been shown, in medium-term studies, to achieve reductions in HbA(1c) without increasing the risk of major hypoglycaemia compared with pre-meal human insulin. The aim of the present 3-year study was to evaluate the long-term safety and efficacy of insulin aspart in people with type 1 diabetes. This was a 30-month extension of a multinational, multicentre, open-label, parallel-group study of 753 people with type 1 diabetes, originally randomly allocated to treatment with insulin aspart or unmodified human insulin before meals, with NPH insulin as basal insulin. Main outcomes measures were hypoglycaemia (major or minor), adverse events and HbA(1c). As insulin aspart became commercially available in some countries before the end of the trial, analyses of HbA(1c) used 30-month data to maintain statistical power. The relative risk estimate of major hypoglycaemia was similar between treatment groups (relative risk [RR] 1.00 [95% CI 0.72, 1.39]). The risk of having a minor hypoglycaemic episode was higher with insulin aspart than with human soluble insulin (RR 1.24 [1.09, 1.39] p=0.024). Insulin aspart was significantly superior to human insulin with respect to overall glycaemic control, with a baseline-adjusted HbA(1c) difference of -0.16 (-0.32, -0.01)% (p=0.035). Insulin aspart was well tolerated and effective during long-term treatment. The HbA(1c) advantage was maintained with insulin aspart without any adverse impact on the rate of major hypoglycaemia.

Aims: To evaluate the pharmacokinetic and pharmacodynamic properties of two different formulations of premixed analogue (mixed biphasic insulin aspart [BIAsp]), BIAsp 30 (30 % soluble insulin aspart [IAsp] and 70 % protaminated IAsp) and BIAsp 70 (70 % soluble IAsp and 30 % protaminated IAsp), in patients with type 1 diabetes using a 12-hour euglycaemic clamp technique., Methods: In this randomised, double-blind, two-period crossover trial, 27 patients with type 1 diabetes received 7 days of treatment with BIAsp 30 three times daily (TID) and 7 days of treatment with BIAsp 70 TID, with a 2 - 6 week washout period between treatment periods. At the start (day 1) and end (day 8) of each treatment period, 12-hour serum IAsp profiles and glucose infusion rate (GIR) profiles were determined during an overnight euglycaemic clamp following subcutaneous (sc) administration of a single 0.3 U/kg dose of trial insulin. All pharmacokinetic and pharmacodynamic endpoints were derived from individual serum IAsp and GIR profiles., Results: The larger fraction of soluble IAsp in BIAsp 70 compared with BIAsp 30 resulted in greater metabolic effect during the initial post-dosing phase (0 - 6 hours) and decreased activity during the late phase (6 - 12 hours). On day 8, AUC (GIR 0 - 6 hours) was 16 % greater for BIAsp 70 than for BIAsp 30 (p = 0.016) and AUC (GIR 6 - 12 hours) was 90 % (p < 0.001) greater for BIAsp 30 relative to BIAsp 70, reflecting the increased proportion of intermediate-acting (protamine co-crystallised) IAsp in BIAsp 30. Overall metabolic effect (AUC (GIR 0 - 12 hours)) was similar for both insulin formulations on day 8 (Ratio, BIAsp 30:BIAsp 70 = 1.04, p = 0.538). Likewise, the larger fraction of soluble IAsp in BIAsp 70 compared with BIAsp 30 resulted in greater exposure to IAsp during the initial post-dosing phase (0 - 6 hours) and a smaller exposure to IAsp during the late phase (6 - 12 hours). On day 8, AUC (IAsp 0 - 6 hours) was 59 % (p < 0.001) greater for BIAsp 70 than for BIAsp 30, and AUC (IAsp 6 - 12 hours) was 61 % (p < 0.001) greater for BIAsp 30 than for BIAsp 70, reflecting the increased proportion of intermediate-acting (protamine co-crystallised) IAsp in BIAsp 30. However, the overall IAsp exposure (AUC 0 - 12 hours) on day 8 was significantly greater for BIAsp 70 than for BIAsp 30 (Ratio, BIAsp 30:BIAsp 70 = 0.73, p < 0.001). The GIR profiles on day 8 were similar to those on day 1. Serum IAsp profiles on day 8 showed a slight increase compared with day 1., Conclusions: The different proportions of soluble and protaminated IAsp result in differences in the pharmacokinetic and pharmacodynamic properties of BIAsp 30 and BIAsp 70. The pharmacokinetic and pharmacodynamic differences observed may allow for flexibility and individualised treatment regimens in patients with diabetes, while maintaining a limited number of daily injections.

A 62-year-old man suffered out-of-hospital cardiac arrest and was treated with mechanical compression-decompression during transport to the hospital. In the emergency department, 28 min after cardiac arrest, spontaneous circulation returned briefly but the patient rapidly became asystolic and mechanical compression-decompression was again applied. After further resuscitation a spontaneous circulation returned and the patient was transferred, deeply comatose, to the coronary intervention laboratory while therapeutic hypothermia was induced. In the laboratory the heart arrested again and coronary angiography was performed during manual CPR revealing a left main stem occlusion. After successful reperfusion of the heart the patient was transferred to the intensive care unit with an intra-aortic balloon pump. The patient was treated with hypothermia for 24 h and awoke without neurological sequelae after a sustained intensive care period of 13 days. The present case is an example of how modern resuscitation principles implementing new clinical and experimental findings may strengthen the chain of survival during resuscitation.

Sudden, unexpected cardiac arrest is a common cause of death. Among patients who are successfully resuscitated, a majority dies without regaining consciousness. Therapeutic hypothermia has recently been shown to improve neurological outcome in two randomized studies and to improve survival in one of them. Based on the two studies, international evidence-based recommendations have been proposed and published (ILCOR). In this review we discuss the theoretical background of hypothermic neuroprotection and therapeutic implications. We propose that victims of cardiac arrest with return of spontaneous circulation and persistent unconsciousness are considered for hypothermia treatment and that data from treated patients are collected in a common website database (see: www.scctg.org) to allow further evaluation of the use of ICU resources, efficacy of hypothermia treatment and potential risks.

Two controlled randomized trials have shown that mild systemic hypothermia after cardiac arrest is beneficial for neurological outcome and one of the studies shows an improved survival rate. A pilot study was performed to evaluate a model of induced hypothermia after cardiac arrest, using cold intravenous fluids and surface cooling with a cold helmet and a coldwater blanket (Thermowrap). The main purpose was to evaluate our cooling method regarding efficacy, safety and usability. Five unconscious patients after cardiac arrest were treated with induced hypothermia of whom three survived with good recovery to six-month follow up. Two patients died in the ICU without regaining consciousness. There were no adverse events during treatment. We conclude that our method is reasonably fast compared to other published methods, it is easy to perform and it offers a good temperature control during cooling and rewarming. Routines for evaluating prognosis and neurological outcome after cardiac arrest and hypothermia treatment need to be revised.

Aims: To compare the effects of the rapid-acting insulin analogue insulin aspart and soluble human insulin on hypoglycaemia and glycaemic control in patients with Type 1 diabetes when injected immediately before meals as part of intensive insulin therapy., Methods: In this multinational, double-blind, randomised, crossover trial, 155 patients with Type 1 diabetes (HbA(1c) < 8.0%) were symmetrically randomised to two 16-week treatment periods on either type of insulin, both injected 0-5 min before meals. NPH insulin was given as basal insulin once or twice daily as needed, and insulin dosages were regularly adjusted using pre-defined algorithms to maintain tight glycaemic control. Treatment periods were separated by a 4-week washout., Results: The rate of major nocturnal (24.00-06.00 h) hypoglycaemic episodes was 72% lower with insulin aspart than with human insulin (0.067 vs. 0.225 events/month; P = 0.001). Total rate of major hypoglycaemia did not differ significantly between treatments (insulin aspart/human insulin relative risk 0.72; 95% CI 0.47-1.09, P = 0.12). The rate of minor events was significantly reduced by 7% with insulin aspart (P = 0.048). Reductions in rate of hypoglycaemia were achieved with maintained overall glycaemic control: Mean HbA(1c) remained constant, slightly below 7.7% on both treatments., Conclusions: The use of insulin aspart in an intensive insulin regimen in patients with tightly controlled Type 1 diabetes led to clinically significant reductions in major nocturnal hypoglycaemia with no deterioration in glycaemic control. Major nocturnal hypoglycaemia appears to be a strong clinical indication for the use of rapid-acting insulin analogues during intensive insulin therapy.

Mitochondria are important in the pathophysiology of several neurodegenerative diseases, and mitochondrial production of reactive oxygen species (ROS), membrane depolarization, permeability changes and release of apoptogenic proteins are involved in these processes. Following brain insults, cell death often occurs in discrete regions of the brain, such as the subregions of the hippocampus. To analyse mitochondrial structure and function in such subregions, only small amounts of mitochondria are available. We developed a protocol for flow cytometric analysis of very small samples of isolated brain mitochondria, and analysed mitochondrial swelling and formation of ROS in mitochondria from the CA1 and CA3 regions of the hippocampus. Calcium-induced mitochondrial swelling was measured, and fluorescent probes were used to selectively stain mitochondria (nonyl acridine orange), to measure membrane potential (tetramethylrhodamine-methyl-ester, 1,1',3,3,3',3'-hexamethylindodicarbocyanine-iodide) and to measure production of ROS (2',7'-dichlorodihydrofluorescein-diacetate). We found that formation of ROS and mitochondrial permeability transition pore activation were higher in mitochondria from the CA1 than from the CA3 region, and propose that differences in mitochondrial properties partly underlie the selective vulnerability of the CA1 region to brain insults. We also conclude that flow cytometry is a useful tool to analyse the role of mitochondria in cell death processes.

The cellular and molecular pathways initiated by traumatic brain injury (TBI) may compromise the function and structural integrity of mitochondria, thereby contributing to cerebral metabolic dysfunction and cell death. The extent to which TBI affects regional mitochondrial populations with respect to structure, function, and swelling was assessed 3 hours and 24 hours after lateral fluid-percussion brain injury in the rat. Significantly less mitochondrial protein was isolated from the injured compared with uninjured parietotemporal cortex, whereas comparable yields were obtained from the hippocampus. After injury, cortical and hippocampal tissue ATP concentrations declined significantly to 60% and 40% of control, respectively, in the absence of respiratory deficits in isolated mitochondria. Mitochondria with ultrastructural morphologic damage comprised a significantly greater percent of the population isolated from injured than uninjured brain. As determined by photon correlation spectroscopy, the mean mitochondrial radius decreased significantly in injured cortical populations (361 +/- 40 nm at 24 hours) and increased significantly in injured hippocampal populations (442 +/- 36 at 3 hours) compared with uninjured populations (Ctx: 418 +/- 44; Hipp: 393 +/- 24). Calcium-induced deenergized swelling rates of isolated mitochondrial populations were significantly slower in injured compared with uninjured samples, suggesting that injury alters the kinetics of mitochondrial permeability transition (MPT) pore activation. Cyclosporin A (CsA)-insensitive swelling was reduced in the cortex, and CsA-sensitive and CsA-insensitive swelling both were reduced in the hippocampus, demonstrating that regulated MPT pores remain in mitochondria isolated from injured brain. A proposed mitochondrial population model synthesizes these data and suggests that cortical mitochondria may be depleted after TBI, with a physically smaller, MPT-regulated population remaining. Hippocampal mitochondria may sustain damage associated with ballooned membranes and reduced MPT pore calcium sensitivity. The heterogeneous mitochondrial response to TBI may underlie posttraumatic metabolic dysfunction and contribute to the pathophysiology of TBI.

The mitochondrial permeability transition (mPT) is considered to be an important mediator of apoptosis and necrosis, and is specifically blocked by cyclosporin A (CsA). CsA has been shown to exert a potent neuroprotective action in vivo when allowed to cross the blood-brain barrier in various animal models of acute neurological insults and neurodegenerative disease. The neuroprotective effect of CsA is considered to be mediated through specific inhibition of the mitochondrial permeability transition pore (mPTP) and through inhibition of neuronal calcineurin activity. Characterization of mPT has mainly been performed in liver and heart mitochondria, and some brain studies have reported a decreased inhibitory effect of CsA and questioned the importance of mPT in brain-derived mitochondria. We have used the de-energized model of swelling to examine the mPT in brain-derived non-synaptosomal mitochondria. Ca(2+)-induced swelling was evaluated by electron microscopy and by measurement of spectrophotometric alterations in light scattering. Permeability transition was readily induced in a majority of the mitochondria at a wide range of Ca(2+) levels and was powerfully inhibited by CsA with a half-maximal effect at approximately 23 nM CsA. The swelling kinetics and CsA effects were comparable to previous findings in de-energized liver and heart mitochondria. Careful characterization of mPT and CsA effects in brain-derived mitochondria is the first step in evaluating newly developed CsA analogues capable of crossing the blood-brain barrier and preferentially entering the brain. The importance of CsA causing a shift of the mitochondrial sensitivity to Ca(2+) in neurological disorders is discussed.

Vulnerable neurons in the hippocampus die 2-3 days after transient global brain ischemia. In the present study, rat brain mitochondria were isolated at different time points (4 h, 24 h and 48 h) after transient global ischemia. Detection of mitochondrially-generated reactive oxygen species, measured through dichlorodihydrofluorescein oxidation, was increased up to 40% relative to control in hippocampal mitochondria at 4 h and 48 h of reperfusion. Ischemia-stimulated oxidative stress was observed with mitochondria oxidizing substrates linked to nicotinamide adenine dinucleotide or flavin adenine dinucleotide, but not in the presence of the respiratory chain inhibitor antimycin A. A slightly decreased Ca(2+) uptake capacity was observed in hippocampal mitochondria during reperfusion. We conclude that transient brain ischemia induces oxidative stress in hippocampal mitochondria., (Copyright 2002 Elsevier Science Ireland Ltd.)

Acute neurodegeneration in man is encountered during and following stroke, transient cardiac arrest, brain trauma, insulin-induced hypoglycemia and status epilepticus. All these severe clinical conditions are characterized by neuronal calcium overload, aberrant cell signaling, generation of free radicals and elevation of cellular free fatty acids, conditions that favor activation of the mitochondrial permeability transition pore (mtPTP). Cyclosporin A (CsA) and its analog N-methyl-valine-4-cyclosporin A (MeValCsA) are potent blockers of the mtPTP and protect against neuronal death following excitotoxicity and oxygen glucose deprivation. Also, CsA and MeValCsA diminish cell death following cerebral ischemia, trauma, and hypoglycemia. Here we present data that strongly imply the mtPT in acute neurodegeneration in vivo. Compounds that readily pass the blood-brain-barrier (BBB) and block the mtPT may be neuroprotective in stroke.

When mouse hippocampal neuronal cultures, 2-3 weeks in vitro, were transiently exposed to combined glucose and oxygen deprivation (100% argon, 5% CO2, in glucose-free medium) for 90 min, extensive neuronal degeneration had occurred after 24 h of reoxygenation. When these cultures were preincubated with cyclosporin A, a calcineurin inhibitor and a blocker of the mitochondrial permeability transition, neuronal death diminished by 30-50%. Similarly, the cyclosporin A analogue, N-Me-Val-4-cyclosporin A, a potent blocker of the mitochondrial permeability transition with no significant calcineurin blocking activity, decreased cell death by 70-80%. Both cyclosporin A and N-Me-Val-4-cyclosporin A markedly attenuated calcium-induced swelling of isolated mouse brain mitochondria by blocking the mitochondrial permeability transition. The potassium thiocyanate-stabilized binding of cyclophilin D to mouse brain mitochondrial membranes was completely prevented by cyclosporin A and N-Me-Val-4-cyclosporin A. Our results strongly suggest that the mitochondrial permeability transition is involved in oxygen/glucose deprivation-induced cell death in vitro. Cyclophilin D and other components of the mitochondrial permeability transition may be important targets for neuroprotective and anti-ischaemic drugs.

The mitochondrial permeability transition pore is an inducer of cell death. During the reperfusion phase after cerebral ischemia, calcium accumulates in mitochondria, and a burst of free radical formation occurs, conditions that favor the activation of the mitochondrial permeability transition pore. Here the authors demonstrate that a blocker of the mitochondrial permeability transition pore, the nonimmunosuppressive cyclosporin A analogue N-methyl-Val-4-cyclosporin A (10 mg/kg intraperitoneally), administered during reperfusion and at 24 hours of reperfusion, diminishes infarct size in a rat model of transient focal ischemia of 2 hours' duration. The mitochondrial permeability transition pore may be an important target for drugs against stroke.

Mitochondria from different regions of the brain were prepared, and the activation of the mitochondrial permeability transition (MPT) by calcium was investigated by monitoring the associated mitochondrial swelling. In general, the properties of the MPT in brain mitochondria were found to be qualitatively similar to those observed in liver and heart mitochondria. Thus, swelling was inhibited by adenine nucleotides (AdNs) and low pH (<7.0), whereas thiol reagents and alkalosis facilitated swelling. Cyclosporin A and its nonimmunosuppressive analogue N-methyl-Val-4-cyclosporin A (PKF 220-384) both inhibited swelling and prevented the translocation of cyclophilin D from the matrix to the membranes of cortical mitochondria. However, the calcium sensitivity of the MPT differed in mitochondria from three brain regions (hippocampus > cortex > cerebellum) and is correlated with the susceptibility of these regions to ischemic damage. Depleting mitochondria of AdNs by treatment with pyrophosphate ions sensitized the MPT to [Ca2+] and abolished regional differences, implying regional differences in mitochondrial AdN content. This was confirmed by measurements showing significant differences in AdN content among regions (cerebellum > cortex > hippocampus). Our data add to recent evidence that the MPT may be involved in neuronal death.

In the present study the time-course of DNA fragmentation following insulin-induced hypoglycemia was examined. In situ localization of DNA breaks were studied by the terminal deoxynucleotidyl transferase-mediated biotin-deoxyuridine triphosphate nick-end labelling method, and the temporal profile of DNA-fragmentation by agarose gel electrophoresis. Cell nuclei displayed terminal deoxynucleotidyl transferase-deoxyuridine triphosphate nick-end labelling within 3 h of recovery following 30 min of a hypoglycemic insult, and DNA from the hippocampus displayed oligonucleosomal fragmentation. Ultrastructural examination of the dentate granule cells showed mitochondrial swelling during the acute phase of the hypoglycemic insult, which preceded the DNA fragmentation seen in the recovery phase. Cyclosporin A but not tacrolimus, prevented mitochondrial swelling and subsequent DNA fragmentation. We conclude that during severe energy deprivation following hypoglycemia, mitochondrial swelling occurs due to mitochondrial permeability transition and that factors are released, which upon recovery can activate processes leading to DNA fragmentation and cell death.

Induction of the mitochondrial permeability transition (MPT) has been implicated in cellular apoptosis and in ischemia-reperfusion injury. During MPT, a channel in the inner mitochondrial membrane, the mitochondrial megachannel, opens and causes isolated mitochondria to swell. MPT and mitochondrial swelling is inhibited by cyclosporin A (CsA), which may also inhibit apoptosis in some cells. Treatment with CsA (50 mg/kg, i.v.) showed a robust reduction of brain damage when administered 30 min before insulin-induced hypoglycemic isoelectricity of 30 min duration. Ultrastructural examination of the dentate gyrus revealed a marked swelling of dendrites and mitochondria during the hypoglycemic insult. In CsA-treated animals, mitochondria resumed a normal and contracted appearance during and after the hypoglycemic insult. Treatment with FK 506 (2 mg/kg, i.v.), a compound with immunosuppressive action similar to that of CsA, was not protective. Studies on the swelling kinetics of isolated mitochondria from the hippocampus showed that CsA, but not FK 506, inhibits calcium ion-induced MPT. We conclude that CsA treatment during hypoglycemic coma inhibits the MPT and reduces damage and that mitochondria and the MPT are likely to be involved in the development of hypoglycemic brain damage in the rat.

Background: Cardiopulmonary resuscitation (CPR) has the potential to save many lives. Used indiscriminately though, it may be harmful and not in the best interest of the patient. An advance directive to refrain from resuscitation in selected patients is probably not uncommon in Sweden, but guidelines ruling this are still generally lacking. This study was performed to evaluate the use and documentation of do-not-resuscitate orders in a Swedish university hospital., Methods: Adult inpatients at 7 medical, 3 surgical and 2 neurological wards, a total of 220, were investigated on one specific day by interviewing the physicians and nurses responsible for their care., Results: We found a discrepancy in doctors' and nurses' perception concerning the appropriateness of CPR in selected patients. CPR was judged by doctors to be inappropriate for 45 patients (20%). Out of these 45 patients, only 24 had a written do-not-resuscitate order in their medical record, in most cases noted as a code word or sign only. Rarely were the patient or his/her relatives involved in the decision-making process., Conclusion: We conclude that a decision to refrain from resuscitation is often not made, even when considered medically and ethically justifiable. Also, the use of coded information as a sole indicator for a patient not to be resuscitated is still common practice. The patient or his/her relatives are rarely involved in this decision.

The effect of the immunosuppressant FK506 on ischaemic neuronal damage was studied in a rat model of transient cerebral ischemia induced by occlusion of both common carotid arteries in combination with hypotension for 10 min. Neuronal damage was assessed morphologically after 4 days of recovery. Treatment with FK506, given at a dose of 2 mg kg-1 by intraperitoneal injections 30 min prior to ischemia and once daily during recovery, decreased neuronal damage by 52% in the hippocampal CA1 region and by 48% in the temporal cortex. The protection was not due to diminished body temperature or a marked reduction of ischaemia-induced synaptic overflow of glutamate. We propose that FK506 decreases neuronal damage either by inhibiting calcineurin-mediated events or by preserving mitochondrial function.

The initial extraction (E) across the blood-brain barrier (BBB) of [99mTc]-d,l-HM-PAO after intracarotid injection was measured in 14 Wistar rats and 6 patients using the double indicator, single injection method with Na-24 as the cotracer. In both series, cerebral blood flow (CBF) was measured using the initial slope of the xenon-133 washout curve after intracarotid bolus injection. In rats, bolus size (20 or 120 microliters), bolus type (saline or 10% albumin), or CBF were changed. First-pass extraction was dependent on CBF (p less than 0.001): With a small bolus of saline and at resting CBF (0.75 ml/g/min), E was 0.81, decreasing to 0.56 at a high CBF (1.5 ml/g/min). The calculated permeability surface area product (PS) increased linearly from 1.2 to 1.5 ml/g/min when CBF increased from 0.8 to 1.5 ml/g/min (p less than 0.01). E was found to increase when the bolus volume of saline was increased from 20 to 120 microliters, while using a 120 microliters bolus containing 10% albumin resulted in a decrease in E. This suggests that HM-PAO binding to albumin is not totally and rapidly reversible during a single passage through brain capillaries and that binding to blood elements may reduce the apparent extraction across brain capillaries. In patients using a bolus of 1 ml saline, E decreased linearly with increasing CBF (r = -0.81, p less than 0.001). For a CBF of 0.59 ml/g/min and an average apparent E of 0.72, an apparent PS product of 0.76 ml/g/min was calculated.(ABSTRACT TRUNCATED AT 250 WORDS)

The uptake and retention in a 2 cm thick brain section was recorded serially by SPECT after i.v. injection of [99mTc]-d,l-HM-PAO (HM-PAO). In 16 patients, the fraction of the administered dose retained by the brain was 5.2 +/- 1%, showing a peak after 40-50s, then decreasing by 10% within the first 10 min and then by only 0.4% per hour. The image contrast was measured in each patient as the regional hemispheric asymmetry difference in percent of the highest value of the two regions. It decreased from 31% at 30-40 s to 25% at 10 min. At 24 h, a value of 19% was reached. Using the images obtained at 10 min after injection, a region to region comparison of the original and corrected HM-PAO images to the xenon-133 regional cerebral blood flow (rCBF) images was performed. Forty-four patients with stroke, epilepsy, dementia, basal ganglia disease, and tumors and control subjects were included in this comparison. The algorithm proposed by Lassen et al. was used to correct the original images for back diffusion of tracer (brain to blood); a good correlation very close to the line of identity between the corrected HM-PAO and xenon-133 data was obtained when using a conversion/clearance ratio of 1.5 and when the noninvolved hemisphere was used as a reference region (r = 0.86, p less than 0.0001). Serial arterial and cerebral venous blood sampling was performed over 10 min following i.v. injection of HM-PAO in six patients. An overall brain retention fraction of 0.37 +/- 0.03 (mean +/- SEM) was calculated from the data. An average CBF of 0.62 +/- 0.12 ml/g/min was determined on the basis of the Fick principle; this compared to a value of 0.59 +/- 0.09 ml/g/min (mean +/- SEM) measured by the xenon-133 inhalation method. The two sets of CBF values correlated linearly with a correlation coefficient of 0.97 (p less than 0.01). Inserting the average CBF value for the hemisphere as measured by the Fick principle into the algorithm described by Lassen et al. yields absolute rCBF values (ml/g/min) directly from the corrected HM-PAO images.(ABSTRACT TRUNCATED AT 400 WORDS)

The in vitro conversion of the lipophilic molecule [99mTc]-d,l-hexamethylpropyleneamine oxime [( 99mTc]-d,l-HM-PAO) to a hydrophilic form was studied in saline, plasma, and blood at 37 degrees C by paper chromatography and by octanol extraction. The octanol:saline ratio was 79.9. From this value and the corresponding octanol: plasma and octanol:blood partitioning values, an estimate of the transport of the lipophilic compound by various components of blood was made: 20% is carried in hemoglobin, 53% by the plasma proteins and 27% by the water phases of the red blood cell and plasma. Octanol extraction provided a rapid method for measuring the radiochemical purity (RCP) of lipophilic [99mTc]-d,l-HM-PAO. In saline, the RCP declined with a half-life of more than 1 h. In human plasma and whole blood, the conversion of [99mTc]-d,l-HM-PAO was biexponential due to the differences in the conversion rates of the d and l isomeric forms. The initial half-life representing the conversion rate of the l form was 1.7 min in blood and 1.4 min in plasma, while the conversion half-life of the d form was 7.4 and 24.4 min, respectively. In vivo, the RCP of arterial blood sampled after an i.v. bolus injection showed an initial peak value of 75% (68-79%) during the initial, first passage of the bolus. It declined to approximately 35% (29-40%) after 1.5 min and reached very low levels (about 1%) at 6 to 10 min. Quantitative measurements of cerebral blood flow using [99mTc]-d,l-HM-PAO necessitates a rapid method for RCP determination in arterial blood such as the one described here.

We have compared the regional distribution of 99Tcm-HMPAO with regional cerebral blood flow (rCBF). CBF was measured by single photon emission computerized tomography (SPECT) using a TOMOMATIC 64 after 133Xe inhalation in 41 patients. With the same SPECT device the distribution of 99Tcm-HMPAO was measured after i.v. injection. High resolution (HR) and low resolution (LR) studies were performed yielding a resolution of 6 to 10 mm (HR) and 15 to 20 (LR). 99Tcm-HMPAO images showed close resemblance to xenon-133 CBF tomograms. Only about 20% of the (decay corrected) brain counts were lost during the first 24 h post injection. A slight decrease in contrast was measured comparing side-to-side asymmetry ratios from the serial studies. This loss of contrast is mainly due to back-diffusion and clearance of a part of the 99Tcm-HMPAO complex from the brain. It could be corrected for by a linearization algorithm. The slight loss of contrast will not be of any importance for the clinical use of this tracer complex.