Impact of crop-manure ratios on energy production and fertilizing characteristics of liquid and solid digestate during codigestion.

The influence of maize silage-manure ratios on energy output and digestate characteristics was studied using batch experiments. The methane production, nutrients availability (N and P) and heavy metals' content were followed in multiflask experiments at digestion times 7, 14, 20, 30 and 60 days. In addition, the available nutrient content in the liquid and solid parts of the digestate was evaluated. Aanaerobic digestion favoured the availability of nutrients to plants, after 61 days 20-26% increase in NH4+ and 0-36% increase in PO4(3-) were found in relation to initial concentrations. Digestion time and maize addition increased the availability of PO4(3-). Inorganic nutrients were found to be mainly available in the liquid part of the digestate, i.e. 80-92% NH4+ and 65-74% PO4(3-). Manure had a positive effect on the methane production rate, whereas maize silage increased the total methane production per unit volatile solids in all treatments.

Properties of amphiphilic oligonucleotide films at the air/water interface and after film transfer.

The self-assembly of amphiphilic hybrid materials containing an oligonucleotide sequence at the air/water interface was investigated by means of pressure-molecular area (Π-A) isotherms. In addition, films were transferred onto solid substrates and imaged using scanning force microscopy. We used oligonucleotide molecules with lipid tails, which consisted of a single stranded oligonucleotide 11 mer containing two hydrophobically modified 5-(dodec-1-ynyl)uracil nucleobases (dU11) at the 5'-end of the oligonucleotide sequence. The air/water interface was used as confinement for the self-assembling process of dU11. Scanning force microscopy of films transferred via Langmuir-Blodgett technique revealed mono-, bi- (Π ≥ 2 mN/m) and multilayer formation (Π ≥ 30 mN/m). The first layer was 1.6 ± 0.1 nm thick. It was oriented with the hydrophilic oligonucleotide moiety facing the hydrophilic substrate while the hydrophobic alkyl chains faced air. In the second layer the oligonucleotide moiety was found to face the air. The second layer was found to cover up to 95% of the sample area. Our measurements indicated that the rearrangement of the molecules into bi- and multiple bilayers happened already at the air/water interface. Similar results were obtained with a second type of oligonucleotide amphiphile, an oligonucleotide block copolymer, which was composed of an oligonucleotide 11 mer covalently attached at the terminus to polypropyleneoxide (PPO).

Comparing environmental consequences of anaerobic mono- and co-digestion of pig manure to produce bio-energy--a life cycle perspective.

The aim of this work was to assess the environmental consequences of anaerobic mono- and co-digestion of pig manure to produce bio-energy, from a life cycle perspective. This included assessing environmental impacts and land use change emissions (LUC) required to replace used co-substrates for anaerobic digestion. Environmental impact categories considered were climate change, terrestrial acidification, marine and freshwater eutrophication, particulate matter formation, land use, and fossil fuel depletion. Six scenarios were evaluated: mono-digestion of manure, co-digestion with: maize silage, maize silage and glycerin, beet tails, wheat yeast concentrate (WYC), and roadside grass. Mono-digestion reduced most impacts, but represented a limited source for bio-energy. Co-digestion with maize silage, beet tails, and WYC (competing with animal feed), and glycerin increased bio-energy production (up to 568%), but at expense of increasing climate change (through LUC), marine eutrophication, and land use. Co-digestion with wastes or residues like roadside grass gave the best environmental performance.

Environmental consequences of processing manure to produce mineral fertilizer and bio-energy.

Liquid animal manure and its management contributes to environmental problems such as, global warming, acidification, and eutrophication. To address these environmental issues and their related costs manure processing technologies were developed. The objective here was to assess the environmental consequences of a new manure processing technology that separates manure into a solid and liquid fraction and de-waters the liquid fraction by means of reverse osmosis. This results in a liquid mineral concentrate used as mineral nitrogen and potassium fertilizer and a solid fraction used for bio-energy production or as phosphorus fertilizer. Five environmental impact categories were quantified using life cycle assessment: climate change (CC), terrestrial acidification (TA), marine eutrophication (ME), particulate matter formation (PMF), and fossil fuel depletion (FFD). For pig as well as dairy cattle manure, we compared a scenario with the processing method and a scenario with additional anaerobic digestion of the solid fraction to a reference situation applying only liquid manure. Comparisons were based on a functional unit of 1 ton liquid manure. System boundaries were set from the manure storage under the animal house to the field application of all end products. Scenarios with only manure processing increased the environmental impact for most impact categories compared to the reference: ME did not change, whereas, TA and PMF increased up to 44% as a result of NH3 and NO(x) emissions from processing and storage of solid fraction. Including digestion reduced CC by 117% for pig manure and 104% for dairy cattle manure, mainly because of substituted electricity and avoided N2O emission from storage of solid fraction. FFD decreased by 59% for pig manure and increased 19% for dairy cattle manure. TA and PMF remained higher compared to the reference. Sensitivity analysis showed that CH4 emission from manure storage, NH3 emission from processing, and the replaced nitrogen fertilizer by the mineral concentrate were important parameters affecting final results. It was concluded that processing fattening pig and dairy cattle manure to produce mineral fertilizer increased overall environmental consequences in terms of CC (except for dairy cattle manure), TA, PMF, and FFD compared to current agricultural practice. Adding the production of bio-energy reduced CC and FFD. Only when NH3 emission from processing was low and bio-energy was produced, overall equal or better environmental performance was obtained for TA and PMF. It was emphasized that real time measurements should be done to enhance the environmental assessment of manure processing technologies. Results of this study present the full environmental consequences of manure processing and key parameters affecting the environmental impact of manure management. Outcomes can be used for decision making and further tackling of environmental problems related to manure management.

Rectal microcirculatory alterations after elective on-pump cardiac surgery.

BACKGROUND: Hemodynamic changes, related to on-pump cardiac surgery, have been reported to impair intestinal perfusion. However, until recently, direct in vivo observation of the intestinal microcirculation was not clinically feasible, and the concept of altered intestinal blood flow in the setting of cardiac surgery depended on indirect observations from other techniques, such as tonometry and microdialysis. To establish the incidence of intestinal microvascular alterations after cardiac surgery, we performed direct in vivo observation of the microcirculation in a clinically accessible part of the intestinal tract in this setting. METHODS: A single-center prospective observational study was conducted in postoperative elective on-pump cardiac surgery patients. Simultaneously, sidestream dark field (SDF) imaging and automated gas tonometry were performed in the rectal pouch within 30 minutes after ICU admission. RESULTS: The rectal median microvascular flow index was 3(3-3) and the proportion of perfused vessels (PPV) was 85% (72-93). The median rectal-to-arterial partial carbon dioxide pressure difference (ΔPCO(2)) was 1.5 (-1.5-8.3) mmHg; 6 (21%) patients had a ΔPCO(2)> 8.3 mmHg, among them 2 (7%) with values> 10.5 mmHg. CONCLUSION: After elective on-pump cardiac surgery, direct in vivo observation of rectal mucosa revealed a PPV <90% in 54% of all patients. At the same time, rectal microcirculatory blood flow appeared to be unaltered. Combining rectal SDF imaging with rectal tonometry revealed a 7% incidence of rectal-to-arterial pCO(2) gap >1.4,kPa, suggesting non-dysoxic perfusion in the majority of patients, despite the observed percentage of non-perfused crypts.

Decontamination of the digestive tract and oropharynx in ICU patients.

BACKGROUND: Selective digestive tract decontamination (SDD) and selective oropharyngeal decontamination (SOD) are infection-prevention measures used in the treatment of some patients in intensive care, but reported effects on patient outcome are conflicting. METHODS: We evaluated the effectiveness of SDD and SOD in a crossover study using cluster randomization in 13 intensive care units (ICUs), all in The Netherlands. Patients with an expected duration of intubation of more than 48 hours or an expected ICU stay of more than 72 hours were eligible. In each ICU, three regimens (SDD, SOD, and standard care) were applied in random order over the course of 6 months. Mortality at day 28 was the primary end point. SDD consisted of 4 days of intravenous cefotaxime and topical application of tobramycin, colistin, and amphotericin B in the oropharynx and stomach. SOD consisted of oropharyngeal application only of the same antibiotics. Monthly point-prevalence studies were performed to analyze antibiotic resistance. RESULTS: A total of 5939 patients were enrolled in the study, with 1990 assigned to standard care, 1904 to SOD, and 2045 to SDD; crude mortality in the groups at day 28 was 27.5%, 26.6%, and 26.9%, respectively. In a random-effects logistic-regression model with age, sex, Acute Physiology and Chronic Health Evaluation (APACHE II) score, intubation status, and medical specialty used as covariates, odds ratios for death at day 28 in the SOD and SDD groups, as compared with the standard-care group, were 0.86 (95% confidence interval [CI], 0.74 to 0.99) and 0.83 (95% CI, 0.72 to 0.97), respectively. CONCLUSIONS: In an ICU population in which the mortality rate associated with standard care was 27.5% at day 28, the rate was reduced by an estimated 3.5 percentage points with SDD and by 2.9 percentage points with SOD. (Controlled Clinical Trials number, ISRCTN35176830.)

[Intra uterine insemination with processed sperm for HIV serodiscordant couples in whom the man is HIV positive]. / Intra-uteriene inseminatie met bewerkt sperma bij HIV-serodiscordante paren met een HIV-positieve man.

The desire to have children is more and more common in HIV serodiscordant couples. The Academic Medical Centre Amsterdam has developed a new treatment protocol for couples in whom the man is HIV positive. Semen is processed to obtain HIV-1 free spermatozoa. These spermatozoa are used for IUI treatment. Thus far, 20 serodiscordant couples underwent 76 IUI cycles. An insemination was performed in 50 cycles (66%). The insemination was cancelled in 26 cycles, because of too many follicles (risk for multiple pregnancy), weekend (no possibilities for virological testing), not enough spermatazoa after preparation, a positive HIV-1 RNA test and other reasons. 10 out of 20 women became pregnant (50%), 8 women were on-going pregnant. The clinical and ongoing pregnancy rate per started cycle was 13% and 11% respectively. 7 babies have thus far been born and none of the mothers or babies seroconverted within this study period. Larger numbers of patients are necessary to support the safety of this program.

Semen parameters of a semen donor before and after infection with human immunodeficiency virus type 1: case report.

Semen samples from a donor who seroconverted for human immunodeficiency virus type 1 (HIV-1) during the period that he was donating at our clinic were stored before and after infection. Semen analysis was done on all of these samples before cryopreservation. Retrospectively, both qualitative and quantitative HIV-1 testing was performed on the cryopreserved semen samples to determine the time of primary HIV-1 infection. After HIV-1 infection, semen volume, sperm motility and the percentage of spermatozoa with normal morphology were reduced compared with the same parameters before HIV-1 infection. HIV-1 RNA was intermittently detectable in semen. HIV-1 infection led to a reduction in semen volume, sperm motility and normal sperm morphology in this donor. However, the clinical significance of these findings is unclear. A longitudinal cohort study on the effects of HIV-1 infection on semen quality is necessary to confirm these findings.

[Preimplantation genetic screening for numerical chromosomal abnormalities in embryos from women of 35 years of age and older; first results in The Netherlands]. / Preïmplantatiegenetische screening op numerieke chromosoomafwijkingen bij embryo's van vrouwen van 35 jaar en ouder; de eerste resultaten in Nederland.

OBJECTIVE: To assess the results of preimplantation genetic screening (PGS) for numerical chromosomal abnormalities in embryos from women of 35 years of age and older. DESIGN: Prospective, descriptive. METHOD: Women who were at least 35 years received standard IVF/ICSI treatment including ovarian hyperstimulation, after which matured oocytes were recovered and inseminated. Three days after insemination, one cell was biopsied from each of the available embryos. In these cells, the copy number of 5 (first 21 patients) or 8 chromosomes was determined using fluorescence in situ hybridisation (FISH). Only embryos with a normal or unknown FISH result were implanted in the uterus. Data were collected in an electronic database. RESULTS: PGS was done for 28 IVF- and 22 ICSI-treatments; the average age of the 50 women at the beginning of treatment was 38.5 years. There were 360 embryos generated; of the 288 biopsied embryos 156 (54%) contained an abnormal number of chromosomes. In 45 women, 1 or 2 embryos were transferred. This resulted in 8 ongoing pregnancies (8/50; 16%) and the birth of 9 children, all of whom were found to be healthy on a paediatric examination at 3 to 10 months of age. In 4 cases there was no embryo transfer because all the embryos were chromosomally abnormal. CONCLUSION: In the first 50 patients in The Netherlands, PGS resulted in an ongoing pregnancy rate of 16% per woman. All children showed normal growth and development.

Pharmacokinetic profiles of nevirapine and indinavir in various fractions of seminal plasma.

Limited data are available on antiretroviral drug concentrations in seminal plasma during a dosing interval. Further, since human ejaculate is composed of fluids originating from the testes, the seminal vesicles, and the prostate, all having different physiological characteristics, drug concentrations in total seminal plasma do not necessarily reflect concentrations in the separate compartments. Five human immunodeficiency virus type 1-infected patients on nevirapine (NVP; 200 mg twice a day [b.i.d.]) and/or indinavir (IDV; 800 mg b.i.d. with ritonavir, 100 mg b.i.d.) regimens used a split ejaculate technique to separate seminal plasma in two fractions, representing fluids from the testes and prostate (first fraction) and fluids from the seminal vesicles (second fraction). Split-ejaculate samples were provided at 0, 2, 5, and 8 h after drug ingestion, on separate days after 3 days of sexual abstinence. NVP and IDV showed time-dependent concentrations in seminal plasma, with peak concentrations in both fractions at 2 and 2 to 5 h, respectively, after drug ingestion. The NVP concentrations were not significantly different between the first and second fractions of the ejaculate at all time points measured and were in the therapeutic range, except for the predose concentration in two patients. The median (range) predose IDV concentrations in the first and second fractions of the ejaculate were 448 (353 to 1,015) ng/ml and 527 (240 to 849) ng/ml, respectively (P = 0.7). In conclusion, NVP and IDV concentrations in seminal plasma are dependent on the time after drug ingestion. Furthermore, our data suggest that NVP and IDV achieve therapeutic concentrations in both the testes and prostate and the seminal vesicles throughout the dosing interval.

The development of spectral EEG changes during short periods of circulatory arrest.

The EEG was monitored in 56 patients during implantation of an internal cardioverter defibrillator. The purpose of this study was to determine the main EEG frequency ranges that represent ischemic changes during short periods of circulatory arrest. The EEG was recorded with a 16-channel common reference montage (Cz). After onset of circulatory arrest, the log spectral changes of three-epoch moving averages were calculated relative to the baseline spectrum. For factor analysis, 17 EEG periods were selected that showed changes progressing to an isoelectrical period. Topographic differences and the time course of quantitative EEG (qEEG) changes were studied in all 56 patients. For each patient the EEG period with the longest duration of circulatory arrest was chosen. Factor analysis revealed four factors that represented the spectral EEG changes occurring during circulatory arrest and recovery. The frequency intervals of these factors were 0 to 0.5 Hz, 1.5 to 3 Hz, 7.5 to 9.5 Hz, and 15 to 20 Hz for all channels. Only minor topographic differences were found in the power of the spectral changes; the sequence of events was similar for all electrode positions. The first EEG change after circulatory arrest was an initial increase in alpha power and a decrease in beta power. On average, after approximately 15 seconds alpha power started to decrease, beta power decreased further, delta-1 power started to increase, and delta-2 power started to decrease. After approximately 25 seconds, the delta-1 power increase appeared to plateau or to decrease. A circulatory arrest longer than approximately 30 seconds resulted in an isoelectrical EEG. After restoration of the circulation, there was a fast transient increase in delta-1 and delta-2 power, followed by a decrease to baseline. alpha and beta power showed a more gradual increase in power toward baseline and were the last to restore after 60 to 90 seconds. In general, the spectral changes in the alpha and beta frequency ranges were most pronounced and consistent. In conclusion, to detect intraoperative cerebral ischemia, monitoring of changes in the four frequency ranges found is preferable to monitoring changes in the classically defined frequency bands. Furthermore, these results stress the importance of the alpha and beta ranges in detecting cerebral ischemia.

Absence of deleted in azoospermia (DAZ) genes in spermatozoa of infertile men with somatic DAZ deletions.

OBJECTIVE: To determine the presence or absence of the deleted in azoospermia (DAZ) gene clusters in the Y-bearing spermatozoa in semen of severely oligozoospermic men or in testicular biopsy samples of azoospermic men with somatic DAZ deletions. DESIGN: Prospective study. SETTING: Academic hospital. PATIENT(S): Nineteen patients attending our clinics for therapeutic intracytoplasmic injection of sperm. INTERVENTION(S): Peripheral blood lymphocytes were used to obtain somatic DNA for analysis using the polymerase chain reaction. Analysis of chromosomes X and Y and the detection of the DAZ gene clusters were carried out with the fluorescence in situ hybridization technique in spermatozoa remaining after intracytoplasmic sperm injection. MAIN OUTCOME MEASURE(S): Presence or absence of the DAZ gene clusters in matched somatic DNA and Y-bearing spermatozoa. RESULT(S): Seven patients appeared to have a somatic DAZ deletion. Three-color fluorescence in situ hybridization showed that all Y-bearing spermatozoa examined from these men carried the same deletion. CONCLUSION(S): The DAZ deletions present in the seven men would all have been transmitted if they had fathered sons through artificial fertilization techniques using the sperm cells examined in this study.

Neurophysiological effects of pediatric balloon dilatation procedures.

Balloon dilatation of valvar and vascular stenoses has become routine therapy in pediatric cardiology. Repeated balloon inflations cause many episodes of low cerebral oxygen delivery. This study is a prospective study to assess the effects of balloon dilatation on cerebral perfusion and oxygenation. The study included 11 patients scheduled for elective catheterization and balloon dilatation at a university pediatric hospital. Blood flow velocity in the middle cerebral artery (Vmca) and regional cerebral oxygen saturation (rSO2) were monitored by means of transcranial Doppler sonography and near infrared spectroscopy, respectively. In group 1, consisting of 6 patients without an intracardiac shunt, inflation of the balloon resulted in a decrease in Vmca followed by a minor decrease in rSO2. In group 2, consisting of 5 patients with an interatrial communication, inflation resulted in an increase in right-to-left shunt fraction, arterial desaturation. and a major decrease in rSO2 with minor changes in Vmca. Balloon dilatation causes an important decrease in cerebral oxygen delivery by different mechanisms. This may lead to serious morbidity and even mortality. Neuromonitoring is a useful tool in assessing the cerebral effects of balloon dilatation and brain recovery.

Biventricular pacing in end-stage heart failure improves functional capacity and left ventricular function.

BACKGROUND: Asynchronous patterns of contraction and relaxation may contribute to hemodynamic and functional impairment in heart failure. In 1993, we introduced biventricular pacing as a novel method to treat heart failure by synchronous stimulation of the right and left ventricles after an appropriate atrioventricular delay. The objectives of this study were to assess the early and long-term effects of this therapy on functional capacity and left ventricular function in patients with severe heart failure and left bundle branch block. METHODS AND RESULTS: Twelve patients with end-stage congestive heart failure, sinus rhythm and complete left bundle branch block were treated with biventricular stimulation at optimized atrioventricular delay. The NYHA functional class and maximal bicycle exercise capacity were assessed. Systolic and diastolic left ventricular function were studied with echocardiography and radionuclide angiography. Data was collected at various intervals during 1-year follow-up. Cumulative survival [95% CI] was 66.7% [40.0,93.4] at 1 year and 50 % [21.8, 78.2] at 2 and 3 years. Median NYHA class improved from class IV to class II at 1 year (p=0.008). After 6 weeks an increase in exercise capacity occurred, which was sustained. A less restrictive left ventricular filling pattern, an increase in dP/dt and left ventricular ejection fraction, and a decrease in mitral regurgitation were observed early and long-term. CONCLUSIONS: Biventricular pacing at optimized atrioventricular delay results in improvement in functional capacity, which is associated with improved systolic and diastolic left ventricular function, and a decrease in mitral regurgitation during short- and long-term follow-up.

Four DAZ genes in two clusters found in the AZFc region of the human Y chromosome.

The DAZ genes are candidate fertility factors that lie within the human Y chromosome's AZFc region, whose deletion is a common cause of spermatogenic failure. The number of DAZ genes has been difficult to determine, in part because the nucleotide sequences of the DAZ genes are nearly identical. Here, fluorescence in situ hybridization and characterization of BAC clones revealed four full-length DAZ genes on the human Y chromosome. They exist in two clusters, each comprising an inverted pair of DAZ genes (3' <-- 5'::5' --> 3'). Analysis of genomic sequences and testicular transcripts suggested that three or four DAZ genes are translated. Each gene contains at least seven tandem copies of a previously described, 2.4-kb repeat unit that encodes 24 amino acids. In addition, two DAZ genes contain tandem copies of a 10.8-kb repeat unit that encodes the RNA-binding domain, which appears to be multimerized in some DAZ proteins. Combining our present results with previous studies, we can reconstruct several steps in the evolution of the DAZ genes on the Y chromosome. In the ancestral Y-chromosomal DAZ gene, amplification of both intragenic repeats began before the human and cynomolgus (Old World) monkey lineages diverged. During subsequent evolution, an inverted duplication of this modified gene occurred. Finally, the resulting two-gene cluster was duplicated, generating the two-cluster/four-gene arrangement found on modern human Y chromosomes.

What is the benefit of preoperative sperm preservation for patients who undergo restorative proctocolectomy for benign diseases?

PURPOSE: In patients with benign colorectal diseases undergoing a restorative proctocolectomy with an ileal pouch-anal anastomosis, semen cryopreservation seems rational to enable the possibility of procreation in case surgery leads to sexual disorders or impotence. The aim of this study was to determine the preoperative and postoperative semen quality in patients undergoing ileal pouch-anal anastomosis. In addition, the study sought to determine the incidence of surgery-induced sexual dysfunction to evaluate the economic efficiency of semen cryopreservation as compared with alternatives such as microsurgical epididymal sperm aspiration. METHODS: Preoperative and postoperative semen analyses were offered to 97 patients with ileal pouch-anal anastomosis with benign colorectal diseases since 1989. The direct costs of the semen cryopreservation program were determined and compared with those of alternatives. RESULTS: In 34 of 40 consecutive patients with ileal pouch-anal anastomosis who made use of preoperative semen preservation, normal sperm concentrations, motility, and morphology were found. Mean semen characteristics of all 23 patients who returned for postoperative analysis were not different from preoperative values, but they were for total sperm number. Two patients developed temporary retrograde ejaculation postoperatively. None of the preserved semen samples was used, thus semen cryopreservation benefited none of these patients. The total costs of semen cryopreservation are between 2.2 and 5 times higher than the costs for one microsurgical epididymal sperm aspiration procedure. CONCLUSIONS: Preoperative semen cryopreservation in patients undergoing ileal pouch-anal anastomosis because of benign colorectal diseases is quite feasible. However, most likely because of improved surgical techniques and the increasing number of effective alternatives, preoperative semen cryopreservation in patients with ileal pouch-anal anastomosis is no longer cost effective.

Changes in cerebral oxygen uptake and cerebral electrical activity during defibrillation threshold testing.

UNLABELLED: During cardioverter-defibrillator implantation, repeated episodes of ventricular fibrillation (VF) are induced. Insufficient recovery of oxygen metabolism may cause neurological sequelae. In this prospective clinical study, we monitored the electroencephalogram (EEG), middle cerebral artery blood flow velocity (Vmca), and jugular bulb oxygen saturation and estimated cerebral oxygen uptake. Results were analyzed for tests requiring a single shock (Group 1) and tests requiring multiple shocks for defibrillation (Group 2). Immediately after the induction of VF, the mean arterial blood pressure (MAP) decreased to < 30 mm Hg, and the Vmca decreased to 0 cm/s. The EEG showed ischemic changes consisting of a decrease of fast, and an increase of slow, activity, progressively declining to isoelectricity within 11 +/- 2 s. After defibrillation, the MAP recovered rapidly regardless of the arrest duration (3 +/- 2 s). The EEG recovered within 17 +/- 9 and 22 +/- 12 s, respectively, for Groups 1 and 2 (P < 0.05) and did not reveal ischemic changes until induction of a subsequent arrest. In Group 1, the cerebral oxygen uptake increased to 191% +/- 31% of baseline values and returned to baseline in 16 +/- 7 s, whereas in Group 2, it increased to 229% +/- 38% (P < 0.05), followed by a significant decrease to less than baseline (85% +/- 18%; P < 0.005), and returned to baseline simultaneously with the Vmca. We conclude that, although restoration to normal of the EEG and cerebral oxygen uptake coincide in short arrests, EEG recovery underestimates metabolic recovery after tests requiring multiple shocks. IMPLICATIONS: Short test intervals have been mentioned as a cause of neurological sequelae after cardioverter-defibrillator implantation. This study demonstrates that although all systemic hemodynamic variables and the electrocardiogram may have returned to normal, cerebral oxygen uptake may still be depressed for a considerable time, especially after tests requiring two or more shocks.