Irreversible Death Research Articles

Protective effect of posterior cerebral circulation on carotid body ischemia.

Carotid Bodies (CB) are fed mainly by External Carotid Artery (ECA) and rarely by Internal Carotid Artery (ICA). We aimed to investigate the effect of Bilateral Common Carotid Artery ligation and BCCAL plus bilateral external carotid artery ligation on CB. This study has been conducted on 30 hybrid male rabbits. Normal CB analyses were made in six of these animals and others divided into two groups. BCCAL has been applied to the 1st group, and the 2nd group has undergone bilateral ECA ligation in addition to BCCAL. After sacrificing the animals, both sides CB were histopathologically observed. Normal and ischemic cells were counted. Bilateral Common Carotid Artery ligation did not cause total atrophy in CB. Partial reversible atrophy of CB was seen in group I, but that atrophy was found to be irreversible and all animals died within one week after ligation in group II. Retrograde blood flow mechanisms and collateral circulation impede the oligemic CB atrophy after BCCAL. But bilateral ECA ligation, in addition to BCCAL, causes both sides irreversible CB atrophy and death of animals within one week of ligation. The CB are parasympathetic paraganglia. They are chemoreceptors and located at the bifurcation zone of common carotid arteries. They are fed mainly by ECA or by its branches and rarely by ICA. As a consequence of this, BCCAL and/or ligation of external branches of common carotid artery may lead to an ischemic impairment of CB. In order to analyse the effect of carotid stenosis on CB, CB were directly examined in 6 of 30 hybrid rabbits. BCCAL was applied to twelve rabbits (group I) with ligation of both ECA in addition to BCCAL were made to the others (group II). Animals were followed up four months in group I; but all of the animals in group II died within one week. From both sides the CB were taken including the carotid bifurcation and histopathological changes were evaluated. As a result, it has been observed that incomplete ischemic lesions have developed in the CB because of retrograde blood flow from posterior circulation to the ECA providing blood for the CB. But in the second group these changes were irreversible and on both sides CB complete atrophy developed in those whose ECA were also ligated bilaterally.

Part 2: Ethical Aspects of CPR and ECC

Part 2: Ethical Aspects of CPR and ECC

Nontraumatic spine disorders: part I

This article discusses several critical nontraumatic emergencies that involve the spine. Metastatic disease, infection of the disc and epidural space, acute disc herniation, epidural hematoma, and epidural lipomatosis may all present with symptoms ranging from localized pain to more severe neurologic sequelae. Several of these entities may progress to irreversible myelopathy or death if the diagnosis is not made in a timely manner. Appropriate radiologic evaluation and accurate interpretation are required to guide necessary treatment for these entities. Clinical presentation, etiology, radiologic findings, and pitfalls of interpretation of these conditions and related entities will be presented.

Neuroprotective Agents in Acute Ischemic Stroke

Recent scientific data suggest that there is a “window of opportunity” between the onset of brain ischemia and irreversible neuronal death. Although neurons can withstand complete absence of blood flow for only minutes, collateral circulation typically surrounds the “core” of the stroke. In these brain regions known as the ischemic penumbra, brain tissue can survive for several hours following stroke onset. Recent studies suggest that neuroprotective agents would give these viable neurons the chance for recovery. This article reviews the mechanisms of ischemic neuronal injury, mechanism of action of neuroprotective agents, current neuroprotective clinical trials, and guidelines for patient care management.

Gene therapy: a rocky start to the new millennium

Ornithine transcarbamylase deficiency is a genetic disorder caused by a deficiency of one of the enzymes in the urea cycle. The urea cycle, which takes place in the liver, removes nitrogen from the blood and converts it to urea, which is then excreted in the urine. Each of the five steps of the urea cycle requires a specific enzyme. When one of these enzymes is missing, nitrogen accumulates and is converted into ammonia instead of urea. Ammonia is toxic – even modest rises in the brain can cause irreversible brain damage and/or death.

Introduction: Centrifuge and Fragmentation

seismic changes inaugurated by desovietization not only recast entire framework of Russia's cultural priorities, production, and reception, but ultimately revised fundamental concepts of what constitutes culture... This introductory material is available in Studies in 20th Century Literature: http://newprairiepress.org/sttcl/vol24/iss1/2 Introduction: Centrifuge and Fragmentation Helena Goscilo University of Pittsburgh seismic changes inaugurated by desovietization not only recast entire framework of Russia's cultural priorities, production, and reception, but ultimately revised fundamental concepts of what constitutes culture. reduction, then withdrawal, of formerly guaranteed state subsidies, a steady barrage of nationwide financial crises amidst announced transition to a market economy, increased contacts with West, and emergence of New Russians as an influential (and highly controversial) quasi-class resulted in comprehensive rethinking and reformation in all spheres. Seventy-year-old habits and fulfilled expectations died a slow but, in several cases, violent and irreversible death. As centralized, government-sponsored model of culture, with its sacrosanct hierarchies and huge organizational networks, ceded to a dizzying welter of discrete, smaller-scale enterprises, seemingly unassailable institutions within traditional structures teetered and crumbled. Literature, art, film, music, theater, and ballet lost not only official sponsorship, but also status and audiences. Under impact of widespread disillusionment with ideology, elimination of censorship, and an initially uncritical receptivity to Western forces, popular culture rapidly dislodged High Culture. axiom the bigger they are, harder they fall acquired vivid life as state publishing houses foundered, mammoth subscriptions to major literary journals evaporated, country's premier libraries and museums (e.g., Lenin Library in Moscow, Hermitage in St. Petersburg) verged on collapse and curtailed their services, Bolshoi Theater broadcast desperate appeals for foreign aid, and film industry shrank to point of near-evanescence. Formerly lionized writers at both extremes of political spec1 Goscilo: Introduction: Centrifuge and Fragmentation Published by New Prairie Press 8 STCL, Volume 24, No.1 (Winter, 2000) trum (Rasputin, Solzhenitsyn, Limonov) proved irrelevant to those cultural developments that galvanized media and urban population. Russian culture of 1990s, in a sense, reflected vagaries of Yeltsin's presidency in its ever-shifting parade of figures and entities enjoying shortlived glory in fickle but tirelessly focused spotlight. (Mark Lipovetsky's article identifies major currents in readership-poor Russian literature of 1990s, while Mikhail Gnedovskii' s article on prize-winning museum in Krasnoiarsk, Siberia, addresses phenomenon of creative vitality on periphery.) Media Might and Pop on Top While Culture as conceived during Soviet era dwindled into an endangered species, new genres overran cultural market, which catered to a steadily growing appetite for visual stimulation and light entertainment, as well as enthusiasm for outsized gesture and violation of cherished taboos. Pulp fiction garnered millions of readers; glossy magazines flooded kiosks and bookstalls; television shows responding to a taste for confessional, scandalous, and voyeuristic thrived; flamboyant, extravagant, and highly publicized receptions, parties, and presentations became a dominant urban form (often dubbed tusovka); sales of pirated recordings, videos, and software grew into a multi-million dollar industry; cafes and privately owned restaurants, clubs, galleries, beauty salons, and countless small businesses materialized almost overnight, altering face of Moscow and transforming it into Cellular-phone City. exclusive Central House of Literati (TsDL), jealously guarded citadel of Moscow's literary elite, became a ruinously expensive culinary haven affordable only to New Russians. While internationally renowned, landmark museums struggled to survive, Marat Gel' man' s modest-sized, programmatically irreverent gallery drew visitors and media coverage with such tongue-in-cheek shows as The Art of Kompromat and, to commemorate Pushkin's bicentennial this year, Fak iu, Danthes!-a title and rhetorical position calculated to shock while eliciting Pushkin-empathy. (The article by Helena Goscilo in this issue analyzes role of glossies during decade.) apparent replacement of monolithic state conglomerates by diverse multiplicity was partly illusory, for nineties witnessed birth of sizable private empires wielding incalculable influence: 2 Studies in 20th & 21st Century Literature, Vol. 24, Iss. 1 [2000], Art. 2 http://newprairiepress.org/sttcl/vol24/iss1/2 DOI: 10.4148/2334-4415.1473

Perspectives of operative endoscopy in fetal medicine

In this review the indications, techniques, results and perspectives of operative fetoscopy are described and discussed. Prenatal invasive therapy is indicated if postnatal therapy comes too late and fetal disease may lead to irreversible damage or death if it is left untreated. Potential candidates for intrauterine surgery are pregnancies with the following problems: diaphragmatic hernia, infravesical obstruction, sacrococcygeal teratoma, chorioangioma, neural tube defects, twin-twin transfusion syndrome and acardiac twin. The aim is to improve the intrauterine situation by minimally invasive surgery and to prevent irreversible damage. After delivery permanent repair is possible in cases with fetal malformations. Diaphragmatic hernia is the best example for the development from maximally invasive open fetal surgery to minimally invasive endoscopic surgery. There is still a lot of experimental work to be done, for example for the correction of diaphragmatic hernia and neural tube defects. However, in other areas such as severe second trimester twin-twin transfusion syndrome, endoscopic surgery is a well established technique in certain centres for fetal medicine. Endoscopic laser coagulation of the vascular placental anastomoses is a causal therapy and shows better results than serial amniodrainages. After 160 laser coagulations performed in our institution, the survival rates are as follows: overall 68 % of fetuses, with two survivors in 54 % and at least one survivor in 83 % of pregnancies.

Neuronal Expression of a Caenorhabditis elegans elav-like Gene and the Effect of Its Ectopic Expression

We examined the expression of a Caenorhabditis elegans (C. elegans) elav-like gene, which we designated elr-1. The elr-1 gene encodes a predicted 456-amino-acid protein containing three putative RNA-binding domains and belongs to the ELAV family, which is functionally involved in neuronal differentiation. Northern blot analysis suggested that the levels of elr-1 mRNA are regulated developmentally. A elr-1::gfp reporter gene under the control of the elr-1 promoter was expressed specifically in the ring ganglia near the nerve ring, the ventral nerve cord (VNC), and the pre-anal and lumbar ganglia. In the VNC, GFP-positive cells were shown to be acetylcholine-producing motor neurons which increased in number as development proceeded, suggesting that elr-1 is expressed in mature neurons. Ectopic expression of ELR-1 protein at the L4 larval and adult stages, but not earlier stages, caused irreversible death, accompanied by uncoordinated movement (Unc), clear (Clr), and egg-laying defective (Egl) phenotypes, which are often observed in mutants with neuronal defects. These results suggest that ELR-1 may have important functions in specific mature neurons in C. elegans.

Granulocytic Sarcoma (Chloroma) of the Small Intestine

Granulocytic sarcoma or Chloroma may develop before, at the time or after presentation of acute myeloid leukemia. We report the case of a 66-year old man presenting with intermittent abdominal pain during one month before developping a peritonitis due to perforation of small bowel followed by irreversible shock and death. Nearly the entire length of small bowel and bone marrow were infiltrated by giant promyelocytic cells. Abnormal circulating cells were never discoverd. The literature is briefly reviewed.

Regulation of apoptosis during development: input from the extracellular matrix (review).

Programmed cell death or apoptosis is an important aspect in organogenesis and tissue remodeling during development. Extensive investigations have led to the identification of many genes that participate in the regulation of cell death execution. These include the caspases and nucleases, which are involved in the degradation of cellular proteins and nuclear DNA to initiate the irreversible death process. In addition, several families of proteins like Bcl-2 superfamily can either prevent or promote cell death. The function of these proteins are getting to be understood. On the other hand, how these proteins are regulated remains to be investigated. This is in part due to the presence of diverse upstream signals that can influence cell fate. One such signal is the remodeling of the extracellular matrix (ECM), which is largely due to the action of matrix metalloproteinases (MMPs). The regulation of MMPs and ECM remodeling has been shown to affect apoptosis in different systems, including the apoptotic remodeling of the intestine during Xenopus laevis metamorphosis and post-lactation involution of the mouse mammary gland. Current evidence suggests that ECM regulates cell fate at least in part through its membrane receptors, the integrins, which in turn send the signal through yet poorly understood pathways to the nucleus to regulate gene expression.

Use of end-tidal carbon dioxide to predict outcome in prehospital cardiac arrest: Ann Emerg Med 1995; 25/6: 762–767

Abstract Study objective: End-tidal CO 2 (ETCOH 2 ) measurement can be used to predict death in prehospital cardiac arrest patients with pulseless electrical activity (PEA). Design: A prospective, observational study. Setting: An urban and rural emergency medical services system in northwestern Washington state. Participants: Ninety consecutive victims of prehospital cardiac arrest with PEA. Interventions: Patients were intubated in the field and treated using standard advanced cardiac life support protocols with on-line medical control. In addition, all patients were evaluated using mainstream ETCO 2 monitoring. In this study, a hypothetical decision was made to cease resuscitative efforts based on an ETCO 2 level of 10 mm Hg or less after 20 minutes of advanced cardiac life support. Results: The study included 90 patients (61 were men) with a mean age of 67.6±13.6 years (range, 27 to 95 years). The initial ETCO 2 averaged 11.7±6.6 mm Hg in nonsurvivors (range, 5 to 50 mm Hg) and 10.9±4.9 mm Hg in survivors (range, 5 to 24 mm Hg) ( P >.672 [NS]). After 20 minutes of advanced cardiac life support, ETCO 2 averaged 3.9±2.8 mm Hg (range, 0 to 12 mm Hg) in patients in whom the theoretical decision was made to cease field resuscitation. In contrast, survivors' ETCO 2 , just before restoration of circulation, averaged 31±5.3 mm Hg (range, 16 to 35 mm Hg) ( P <.0001). Using an ETCO 2 of 10 mm Hg or less as a theoretical threshold to predict death in the field successfully discriminated between the 16 survivors to hospital admission (those that achieved return of spontaneous circulation) and 75 prehospital deaths. Of the 16 survivors to hospital admission, 9 died in the hospital, and 7 were discharged from the hospital alive. In 13 of the 16 survivors, the first evidence of return of spontaneous circulation, before a palpable pulse or blood pressure, was a rising ETCO 2 . The logistic-regression parameters for the model are 4.4391+ETCO 2* -0.3624 ( P Conclusion: This study suggests that a low ETCO 2 (10 mm Hg or less) can be used to predict irreversible death in patients with pulseless electrical activity undergoing prehospital advanced cardiac life support. If future studies validate this model, use of ETCO 2 may allow for triage decisions in the field. [Wayne MA, Levine RL, Miller CC: Use of end-tidal carbon dioxide to predict outcome in prehospital cardiac arrest. Ann Emerg Med June 1995;25:762-767.]

Use of End-Tidal Carbon Dioxide to Predict Outcome in Prehospital Cardiac Arrest

Study objective: End-tidal CO 2 (ETCOH 2) measurement can be used to predict death in prehospital cardiac arrest patients with pulseless electrical activity (PEA). Design: A prospective, observational study. Setting: An urban and rural emergency medical services system in northwestern Washington state. Participants: Ninety consecutive victims of prehospital cardiac arrest with PEA. Interventions: Patients were intubated in the field and treated using standard advanced cardiac life support protocols with on-line medical control. In addition, all patients were evaluated using mainstream ETCO 2 monitoring. In this study, a hypothetical decision was made to cease resuscitative efforts based on an ETCO 2 level of 10 mm Hg or less after 20 minutes of advanced cardiac life support. Results: The study included 90 patients (61 were men) with a mean age of 67.6±13.6 years (range, 27 to 95 years). The initial ETCO 2 averaged 11.7±6.6 mm Hg in nonsurvivors (range, 5 to 50 mm Hg) and 10.9±4.9 mm Hg in survivors (range, 5 to 24 mm Hg) ( P >.672 [NS]). After 20 minutes of advanced cardiac life support, ETCO 2 averaged 3.9±2.8 mm Hg (range, 0 to 12 mm Hg) in patients in whom the theoretical decision was made to cease field resuscitation. In contrast, survivors' ETCO 2, just before restoration of circulation, averaged 31±5.3 mm Hg (range, 16 to 35 mm Hg) ( P<.0001). Using an ETCO 2 of 10 mm Hg or less as a theoretical threshold to predict death in the field successfully discriminated between the 16 survivors to hospital admission (those that achieved return of spontaneous circulation) and 75 prehospital deaths. Of the 16 survivors to hospital admission, 9 died in the hospital, and 7 were discharged from the hospital alive. In 13 of the 16 survivors, the first evidence of return of spontaneous circulation, before a palpable pulse or blood pressure, was a rising ETCO 2. The logistic-regression parameters for the model are 4.4391+ETCO 2*-0.3624 ( P<.0001). Sensitivity was 97.3%; specificity 100%; positive predictive value 100%; and negative predictive value 88.9%. Conclusion: This study suggests that a low ETCO 2 (10 mm Hg or less) can be used to predict irreversible death in patients with pulseless electrical activity undergoing prehospital advanced cardiac life support. If future studies validate this model, use of ETCO 2 may allow for triage decisions in the field. [Wayne MA, Levine RL, Miller CC: Use of end-tidal carbon dioxide to predict outcome in prehospital cardiac arrest. Ann Emerg Med June 1995;25:762-767.]

Computer analyzed histology of ischemic injury to the gut

Histopathologic alterations in the intestinal mucosa after ischemic injury have been extensively described in the literature, but these descriptions have primarily been qualitative in nature. The purpose of this study was twofold: (1) to establish parameters obtained by computerized digital image analysis that would be useful in identifying ischemic injury, and (2) to use these parameters to identify the critical period of intestinal ischemia producing measurable histopathologic change. Seventy male Sprague-Dawley rats weighing 80 to 150 g underwent various times of gut ischemic injury by vascular occlusion of the superior mesenteric artery and vein with a microaneurysm clamp. The clamp times were 0, 1, 20, 30, 40, 50, 60, 70, 80, and 90 minutes. Histological sections of the terminal ileum were quantitatively analyzed using Jandel Scientific's computerized morphometric image analysis system. Parameters studied were surface index (SI, surface length per linear unit of mucosa), average villous thickness (AVT), average villous height (AVH), and the number of villous cells/100 μm length (VC). Ischemic times of 1, 20, 30, and 40 minutes produced no measurable injury as compared with baseline ( P[40 minutes versus baseline] = SI, .60; AVT, .84; AVH, .93; VC, .09). At 50 minutes, SI and AVH showed a measurable change from baseline ( P[50 minutes versus baseline] = SI, .01; AVH, .02). Sixty minutes of ischemic time produced measurable change in all parameters ( P[60 minutes versus baseline] = SI, .007; AVT, .001; AVH, .002; VC, .007). Ischemic times beyond 60 minutes produced significant changes from baseline, but were not measurably different from that of 60 minutes ( P[90 minutes versus 60 minutes] = SI, .15; AVT, .89; AVH, .43; VC, .18). Interestingly, when each histological parameter was analyzed over time, the earliest measurable changes were noted in the SI and AVH between 40 and 50 minutes of ischemia. During this time period, there was a reduction in surface index ( P = .03) and average villous height ( P = .005) with a concomitant increase in the Chiu score ( P = .02). These results suggest that the critical period of ischemia producing significant histopathologic change without irreversible death lies within 40 to 50 minutes. Furthermore, morphometric analysis can be used with reliability in quantitatively evaluating the degree of gut ischemic injury, allowing a more objective and reproducible measurement of ischemic change.

Competition for assimilates and fruit position affect fruit set in indeterminate greenhouse tomato

Localization and characterization of fruit set in winter tomato crops was investigated to determine the main internal and external controlling factors and to establish a quantitative relationship between fruit set and competition for assimilates. Individual fruit growth and development was assessed on a beef tomato cultivar during the reproductive period (first nine inflorescences). A non-destructive photograph technique was used to measure fruit growth from very early stages of their development and then calliper measurements were made on big fruits. From these measurements we determined the precise developmental stage at which fruit growth stopped. Fruit potential growth, which is defined as the growth achieved in non-limiting conditions for assimilate supply, was also assessed by this method on plants thinned to one flower per inflorescence. The latter was used to calculate the ratio between actual and potential growth, which was found to be a good index of the competition for assimilates. Time lags of fruit set were observed mainly on distal organs. When more than three flowers were left on each inflorescence, distal organs developed at the same time as proximal organs of the following inflorescence. Consequently they were submitted to a double competition within one inflorescence and among inflorescences. It was shown that, what is commonly named 'fruit set failure', is not an irreversible death of the organ and that a small fruit could resume growth after a delay of several weeks as soon as the first fruits ripened and thus ceased to compete for assimilates. In that case proximal fruits resumed growth before distal ones. The delayed fruits contained only few seeds but a germination test confirmed that fertilization took place before fruit set failed. Competition for assimilates was calculated during plant development by the ratio between actual and potential fruit growth. Potential growth of proximal fruits was strongly dependent on the position of the inflorescence on the stem, whereas potential growth of distal fruits was lower than or equal to that of proximal fruits of the same inflorescence and it was independent on the inflorescence position. We took into account both inflorescence and fruit positions to establish a quantitative relationship between fruit set of individual inflorescences and the ratio between actual and potential fruit growth.

Phosphorous and proton spectroscopy in relation to near incarceration and incarceration of the human brain

We report 3 cases of 31P and 1H MR spectroscopy (MRS) performed at different stages on patients with clinical signs of near or fulminant incarceration of the brain. The measurements were made on a whole body, 1.5 T scanner. 1H-MRS was obtained with the STEAM sequence and 31P-spectra were obtained using the chemical shift imaging technique. Medical treatment including controlled ventilation and sedation of the patients was carried out during the examination. The first patient was evaluated on days 6 and 10 after evacuation of an acute subdural haematoma. An intracranial pressure of 35 mm Hg was registered during the first examination. The 2nd patient had suffered a spontaneous intracerebral haemorrhage and showed clinical signs of imminent incarceration during the examination. The 3rd patient showed clinical signs of incarceration just prior to the examination. In the 1st patient 1H-MRS showed a 3-fold increase in the concentration of choline-containing compounds and a small decrease in N-acetyl aspartate from the 1st to the 2nd examination, which we interpret as a loss of neurones. In case 2 only small changes in metabolism could be detected, indicating that, despite signs of imminent clinical incarceration, the energy supply to the brain was substantial. 1H-MRS of the 3rd patient showed massive lactate concentration, and 31P-MRS revealed the total absence of high-energy phosphorous compounds leaving only one single peak of inorganic phosphate, indicating irreversible brain death.

Death, dying and revival: ethical aspects

The time when restoration of an organism’s vital functions seemed more a fantasy than a reality has passed. The question of when damage incompatible with life occurs in a dying organism still remains. Nowadays, the need to fight unnecessary death is occupying a more and more dominant place in our concept of the last stages of life. The increasing number of resuscitation units in our hospitals points to the fact that physicians understand the use of organized measures aimed at developing resuscitation help, and do not consider it possible to treat patients in terminal states without such measures. Emphasis is placed on a complete and adequate restoration of neurologic regulation of physiologic functions. With this has come the development of resuscitation methods, the understanding of the scientific facts of that period of life and identification of those processes which lead to irreversible death of tissues and those which can be considered reversible with resuscitation Physicians must continue to struggle for the life of a dying person and help him in every way they can till the last patient’s breath. This is why any form of euthanasia contradicts a physician’s outlook. Euthanasia is something opposite to resuscitation. The aim of euthanasia is to alleviate terminal sufferings of a dying person by hastening the moment of death, while the aim of resuscitation is to restore extinguishing life of a still viable organism. Modern medicine has at its disposal a wide spectrum of means and methods to create a more balanced psychic state of a dying patient and simultaneously render him medical help. Investigation of death and revival has become an essential part of modern biology and medicine, being at the same time the essence of reanimatology. These pathophysiological phenomena have not yet been solved and death is still a mystery. Undoubtedly, its comprehension will not only deepen out theoretical ideas about life and death, but also arm investigators - resuscitators - with new approaches and methods to preserve and restore life’. The problems of resuscitation and the light for life of a dying person are common.

Avoiding Complications in Arterial Surgery

Our approach to vascular surgery is to recognize and contemplate perioperative complications and devise strategies to avoid them. These strategies are detailed in several of the major areas of arterial surgery. It is far easier to avoid complications than to deal with them when they occur. This is especially true for some complications in vascular surgery, such as intraoperative or postoperative cerebrovascular accident, atheroembolic complications, or distal thrombosis in lower-extremity reconstruction, that may result in either irreversible morbidity or death.

Effect of inhalation anesthetics on swimming activity of artemia salina.

The swimming movement of artemia salina in the artificial sea water was measured by using the video camera system in the absence and presence of anesthetics, i.e. enflurane, halothane, and isoflurane. The movement of artemia looked random at a glance but the obtained distribution curve for the swimming speed was skewed toward the high speed side somewhat resembling a Maxwellian distribution curve seen in the statistics of ideal gases. When anesthetic were added, the distribution curve became sharpened and shifted to the low speed side, which is similar to a behavior of ideal gases when they are cooled down. The mean swimming-speed was decreased eventually leading to an irreversible death with increasing the anesthetic dose. The activity was analyzed by using the hydrodynamic equation. The ED(50), which is a dose that causes a 50% reduction in the activity, of all anesthetics used in this study was quite similar to the MAC values for human. It was also suggested that an interaction between anesthetics and artemia was highly cooperative since the larger Hill coefficients were obtained for all three anesthetics used.

Assessment of renal function in the patient receiving chemotherapy

With foresight, knowledge, and an awareness of the problem, nephrotoxicity associated with chemotherapy can be prevented or minimized, thereby avoiding irreversible renal failure or death. Careful assessment of those patients at risk for renal damage and the identification of early signs/symptoms of renal impairment are key steps in the prevention and early detection of renal dysfunction. The purpose of this article is to describe the clinical and laboratory manifestations of renal toxicity, as well as the nurse's role in the assessment of nephrotoxicity.

The Effects of Vasodilation with Prostacyclin on Oxygen Delivery and Uptake in Critically Ill Patients

We hypothesized that inadequate oxygenation of peripheral tissues may be unrecognized in critically ill patients and may worsen their prognosis. To test this hypothesis, we measured oxygen delivery to tissues, oxygen uptake, and the extraction ratio (uptake/delivery) before and during a 30-minute infusion of a vasodilator, prostacyclin (5 ng per kilogram of body weight per minute), in 27 critically ill patients with acute respiratory failure. Prostacyclin produced an increase in oxygen delivery (median value before vs. during infusion, 375 vs. 492 ml of oxygen per minute per square meter of body-surface area, P less than 0.001) that was similar in the 14 patients who survived and the 13 who died. This increase in oxygen delivery was associated with a significantly greater increase in oxygen uptake in the patients who died as compared with the survivors (median increase, 19 vs. 5 percent, P less than 0.001). In the survivors, the oxygen extraction ratio fell (median change, -17 percent; range, -27 to -6 percent) and the mixed venous oxygen tension increased. In the patients who died, the extraction ratio rose (median change, 11 percent; range -24 to +40 percent) and the mixed venous oxygen tension did not change. These data suggest the presence of a substantial oxygen debt in patients who subsequently die. Inadequate tissue oxygenation, which may be difficult to recognize, appears to be an important mechanism contributing to the development of irreversible multiple organ failure and subsequent death in some patients with acute respiratory failure.