bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinder der Täter: Söhne und Töchter und ihre Nazi-Väter1
Authors: Pontzen Walter
Published: April 2003

Leider besteht für diesen Artikel keine Zusammenfassung. Als Einstieg stellen wir den Textanfang zur Verfügung. Nach Beendigung des Zweiten Weltkrieges fand die Auseinandersetzung mit dem Nationalsozialismus und dessen Folgen in Deutschland nur sehr zögernd statt. Eine Ausgrenzung der Täter war selten. Sippenhaftung im eigentlichen Sinne kam im Gegensatz z.B. zu Kindern holländischer oder französischer Kollaborateure nicht oder nur selten vor, vielleicht vor dem Hintergrund des dunklen Gefühls der eigenen Beteiligung. Eine Auseinandersetzung mit den Eltern war somit keine Auseinandersetzung, die von aussen aufgezwungen wurde. Das Leiden der Kinder von Tätern war kein Leiden, das von der Gesellschaft aufgezwungen war, sondern, worauf Gertrud Hardtmann [1992, 1995] hinwies, eher ein privates und fand im Familienkreis statt bzw. fand eben nicht statt. Die Väter, meist handelte es sich ja um die Väter und nicht um die Mütter, hatten Angst, dass ihre Verbrechen öffentlich und sie dafür bestraft würden. Sie hatten Angst vor der äusseren Strafe, aber keine Angst vor der inneren. Schuld- und Schamgefühle gab es wohl eher selten. Diese Last, die Last der Schuld- und Schamgefühle, wurde der zweiten Generation aufgebürdet: Während die erste Generation die Verbrechen begangen hat, leidet die zweite, die Generation der Kinder, paradoxerweise unter den zu den Verbrechen gehörenden Scham- und Schuldgefühlen.
Posterior Semicircular Canal Type Benign Paroxysmal Positioning Vertigo with Ageotropic Paroxysmal Positioning Nystagmus
Authors: Rapoport Abraham , Sadeh Menachem
Published: April 2003

We report on 3 patients with typical benign paroxysmal positioning vertigo (BPPV) and atypical, paroxysmal positioning nystagmus. When the Dix-Hallpike test was performed, the patients exhibited an ageotropic nystagmus, different from that classically described in posterior semicircular canal BPPV. It was torsional-vertical with the vertical component beating downwards, and the torsional component was beating away from the lowermost ear. In both left and right Dix-Hallpike positions, the upper poles of the eyes were turning away from the lowermost ear. The atypical ageotropic paroxysmal positional nystagmus of the posterior semicircular canal was observed in the evolution of the BPPV in 2 patients and on the first examination in the third. Two patients had changing patterns of paroxysmal positioning nystagmus.
Why and How We Study Human Learning on Basic Auditory Tasks
Authors: Wright Beverly A.
Published: April 2003

Human listeners can often improve their ability to discriminate sounds with practice. We have been using behavioral techniques to examine the patterns of learning and generalization on basic auditory tasks, such as the discrimination of the time interval between two sounds. Here we briefly state our motivations for examining learning on these basic tasks, describe our experimental paradigm, and provide an example of our results.
Auditory Pathway Encoding and Neural Plasticity in Children with Learning Problems
Authors: Kraus Nina
Published: April 2003

An inability to process auditory information, especially speech, characterizes many children with learning and attention problems. Our working hypothesis is that these speech-sound perception problems arise, at least in some cases, from faulty representation of the speech signal in central auditory centers. Preconscious neurophysiologic representation of sound structure by central auditory pathway neurons can be reflected by subcortical and cortical aggregate neural responses. These neurophysiologic responses can be modified by perceptual learning. Our research has shown that some children with learning problems demonstrate abnormal perception and neural representation of certain speech sounds. Differences between normal and learning-impaired groups can be attributable to aspects of neural synchrony that are reflected in aggregate neural responses. Deficiencies in neural synchrony in these children are apparent in subcortical (as well as cortical) representations of speech-sound structure, and these timing deficits are related to performance on speech-sound perception and learning measures. Moreover, impaired perception and neurophysiologic encoding of speech sounds can be improved with cue enhancement and can be modified by perceptual learning associated with auditory training.
Deafness-Induced Changes in the Auditory Pathway: Implications for Cochlear Implants
Authors: Shepherd Robert K. , Hardie Natalie A.
Published: April 2003

A profound sensorineural hearing loss induces significant pathological and atrophic changes within the cochlea and central auditory pathway. We describe these deafness-induced morphological and functional changes following controlled lesions of the cochlea in experimental animals. Such changes are generally consistent with the limited number of reports describing deafness-induced changes observed in human material. The implications of these pathophysiological changes within the auditory pathway on cochlear implant function are discussed. Finally, the plastic response of the deafened auditory system to electrical stimulation of the auditory nerve is reviewed in light of the clinical implications for cochlear implant recipients.
Non-Linear Aspects of Outer Hair Cell Transduction and the Temporary Threshold Shifts after Acoustic Trauma
Authors: Patuzzi Robert
Published: April 2003

The 200-Hz cochlear microphonic potential (CM) and the compound action potential (CAP) of the auditory nerve evoked by tone-bursts were recorded in the basal turn of the cochlea of anaesthetised guinea pigs, before and after exposure to traumatic high-frequency tones that produce a temporary threshold shift (TTS) in this cochlear region. The drop in CM and the TTS were highly correlated, suggesting that it is the disruption of the outer hair cells generating the CM that causes the TTS. The previously measured rise in endocochlear potential and drop in organ of Corti K+ levels suggest that the TTS is due to a temporary closure of outer hair cell mechanoelectrical transduction (MET) channels, which produces a drop in the mechanical sensitivity of the organ of Corti, due to disruption of the active process provided by outer hair cells. The time course of the onset and recovery of TTS is consistent with a kinetic folding and refolding of MET channels over a time course of hours and days. Mathematical modelling of this putative channel folding suggests that TTS recovery may be accelerated by the presentation of additional sounds during the recovery period. We present electrophysiological data (CM and CAP measurements) showing that this accelerated recovery occurs. Using two-tone complexes (phase-locked 5- and 10-kHz traumatic tones, and 10-kHz traumatic tones with 25-Hz bias tones), we also show that the mechanisms producing TTS are non-linear and asymmetric, and that the greatest ‘trauma’ occurs when the hair bundles of outer hair cells are deflected away from the basal body of these cells (i.e. in the direction normally causing hyperpolarisation of the cell membrane potential).
Mechanoelectrical and Voltage-Gated Ion Channels in Mammalian Vestibular Hair Cells
Authors: Eatock Ruth Anne , Hurley Karen M. , Vollrath Melissa A.
Published: April 2003

Mammalian vestibular afferents respond robustly to head movements at low frequencies and provide input to reflexes that control eye, head and body position. Vestibular organs have distinctive regions and hair cells: Type II cells receive bouton afferent endings and type I cells receive large calyx afferent endings. In the rodent utricle, type II cells are broadly tuned to frequencies between 10 and 30 Hz. Other recent data suggest that otolith organs function in this frequency range, which is higher than previously imagined. Some of the tuning derives from adaptation of the transducer current, which is best fitted with a double exponential decay with time constants of ∼4 and 40 ms. Further tuning is provided by basolateral conductances, principally outwardly rectifying, voltage-gated K+ conductances. The kinetics of the K+ currents tend to vary with location in the sensory epithelium and therefore may contribute to regional variation in afferent physiology. Type I hair cells have a large, negatively activating K+ conductance, gK,L, that confers a very low input resistance and therefore attenuates the receptor potential. This may reduce nonlinearity in the receptor potential, a possibly useful feature for the motor reflexes served by the vestibular system. On the other hand, the small receptor potentials together with unusually negative resting potentials are hard to reconcile with calcium-mediated quantal transmission. This problem may be overcome by factors that inhibit gK,L’s activation at resting potential. Also, the calyx may support nonquantal transmission.
The Synaptic Physiology of Cochlear Hair Cells
Authors: Fuchs Paul
Published: April 2003

Mechanosensory hair cells of the vertebrate inner ear are so-called ‘short’ receptors that communicate to the central nervous system by way of chemical synapses with afferent neurons. In turn, hair cells are the targets of olivocochlear fibers that carry efferent inhibitory feedback from the brain. These synaptic activities contribute to, or modulate the hair cell’s receptor potentials through the gating of associated ion channels. Thus for example, voltage-gated calcium channels open to trigger vesicle fusion and release of transmitter by entry of extracellular calcium. The inward calcium current also depolarizes the membrane and could lead to generation of ‘all-or-none’ action potentials. However, regenerative depolarization is prevented in most hair cells by prominent voltage-gated potassium conductances that rapidly repolarize the membrane. The magnitude and speed of these delayed potassium conductances determine the size and shape of the resulting receptor potential, and subsequent transmitter release, produced by sound. Efferent feedback is provided by the release of acetylcholine (ACh) from olivocochlear nerve fibers onto outer hair cells in the mammalian cochlea. The hair cell’s ACh receptors are ligand-gated cation channels related to the nicotinic receptors of nerve and muscle. Calcium influx through the ACh receptors activates nearby calcium-gated potassium channels, resulting in hyperpolarization and inhibition of the hair cell. Calcium influx during efferent inhibition is regulated by a ‘synaptic cistern’ that also may act as a calcium store that is triggered by ACh under some conditions.
A Role for Purinergic Receptors at the Inner Hair Cell-Afferent Synapse?
Authors: Robertson Donald , Paki Bardia
Published: April 2003

Previously published evidence is reviewed for a functional role of ATP and its receptors at the chemical synapse between the mammalian inner hair cell and the primary afferent dendrites of the VIIIth nerve. New findings are also presented, both from gross cochlear potentials and single neurone recordings during intracochlear perfusion of ATP-receptor antagonists and agonists. Both the previous and present results are consistent with the notion that endogenous ATP may act to regulate the excitability of the primary afferent dendrite, possibly acting on P2X2 receptors.
Using Artificial Intelligence to Predict the Equilibrated Postdialysis Blood Urea Concentration
Authors: Fernández Elmer A. , Valtuille Rodolfo , Willshaw Peter , Perazzo Carlos A.
Published: April 2003

Total dialysis dose (Kt/V) is considered to be a major determinant of morbidity and mortality in hemodialyzed patients. The continuous growth of the blood urea concentration over the 30- to 60-min period following dialysis, a phenomenon known as urea rebound, is a critical factor in determining the true dose of hemodialysis. The misestimation of the equilibrated (true) postdialysis blood urea or equilibrated Kt/V results in an inadequate hemodialysis prescription, with predictably poor clinical outcomes for the patients. The estimation of the equilibrated postdialysis blood urea (eqU) is therefore crucial in order to estimate the equilibrated (true) Kt/V. In this work we propose a supervised neural network to predict the eqU at 60 min after the end of hemodialysis. The use of this model is new in this field and is shown to be better than the currently accepted methods (Smye for eqU and Daugirdas for eqKt/V). With this approach we achieve a mean difference error of 0.22 ± 7.71 mg/ml (mean % error: 1.88 ± 13.46) on the eqU prediction and a mean difference error for eqKt/V of –0.01 ± 0.15 (mean % error: –0.95 ± 14.73). The equilibrated Kt/V estimated with the eqU calculated using the Smye formula is not appropriate because it showed a great dispersion. The Daugirdas double-pool Kt/V estimation formula appeared to be accurate and in agreement with the results of the HEMO study.
A Comparative Study of Blood Pressure Control with Short In-Center versus Long Home Hemodialysis
Authors: McGregor David O. , Buttimore Adrian L. , Lynn Kelvin L. , Nicholls M. Gary , Jardine David L.
Published: April 2003

We conducted a randomized crossover trial to establish, within patients, whether long-slow hemodialysis (HD) was associated with better blood pressure (BP) control than standard HD. Nine home HD patients, not on antihypertensive drugs, were dialyzed to the same eKt/Vurea and target weights for 6–8 h (LD) at home and for 3.5–4.5 h (SD) in the dialysis center 3 times weekly in randomized sequence, with each phase lasting 8 weeks. Ambulatory BP, bioimpedance, neurohormones and autonomic function were measured in each phase. Pre- and postdialysis systolic, ambulatory systolic and diastolic BP were all higher with SD than with LD and intradialysis hypotension was more common. Weight, ECF volume and neurohormones did not differ between treatments. Muscle sympathetic activity was increased in both phases and cardiac sympathetic activity tended higher during SD. These findings suggest that additional factors to ECF volume may contribute to the superior BP control produced by long-slow HD.
Familial Homozygous Hypercholesterolemia: Effective Long-Term Treatment with Cascade Double Filtration Plasmapheresis
Authors: Demetriou Kyproula , H’Maltezou Eleni , Pierides Alkis M.
Published: April 2003

Background: Homozygous familial hypercholesterolemia (FH) is a rare disease with an incidence of 1 in 1 million births. It is characterized by blood cholesterol levels over 600 mg/dl and the development of extensive cutaneous xanthomata before the age of 5. Severe premature coronary artery disease results in fatal myocardial infarctions within the first two decades of life. The absence of LDL receptors makes homozygous FH resistant to treatment with most HMG-CoA reductase inhibitors, and alternative methods of removing cholesterol have been employed. Methods: We used the ASAHI plasauto-IQ double filtration cascade plasmapheresis to treat 2 young brothers aged 14 and 11 years and 6 months for 5 years and 1 month and 3 years and 10 months, respectively. The elder brother has received 136 double filtration treatments at 2-week intervals and the younger brother 100 such treatments without complications. Results: During the period of treatment the average pretreatment total serum cholesterol level for patient 1 was 442 mg/dl. The average posttreatment value was 163 mg/dl. The average fall in total serum cholesterol with each treatment was 63.2%. The mean total serum cholesterol for all the periods of treatment was calculated at 303 mg/dl. For the 2nd patient, the average pretreatment value of total serum cholesterol was 435 mg/dl. The posttreatment value was 124 mg/dl and the average fall 71.5%. The calculated mean total serum cholesterol for all periods of treatment was 280 mg/dl. Conclusions: Double filtration cascade plasmapheresis at 2-week intervals provides an effective and safe long-term treatment for patients with homozygous FH. The achieved reduction in serum cholesterol allows complete resolution of cutaneous xanthomata, arrests previous atherosclerosis, and prolongs normal life.
Proinflammatory Cytokines in Heart Disease
Authors: Dinarello Charles A. , Pomerantz Benjamin J.
Published: April 2003

Proinflammatory cytokines affect nearly all tissues and organ systems, and the vasculature is no exception. Although a considerable amount of research has focused on the role of the two most prominent proinflammatory cytokines, interleukin-1 (IL-1) and tumor necrosis factor (TNF), in the pathogenesis of sepsis and septic shock, the role of these and other cytokines in the pathogenesis of atherosclerotic lesions of the coronary artery, the acute ischemic event associated with myocardial infarction, the progression of myocardiopathies or the loss of myocardial function in congestive heart failure is a relatively recent discovery. Moreover, there has also been significant investigation of the cardioprotective effects of cytokines. Most of the attention has focused on the acute coronary syndromes and the myocardial suppression that takes place as a result of acute ischemia. The potential for anticytokine-based therapies in treating heart disease is great. Parenteral TNF-α neutralization and IL-1 receptor blockade are presently used to treat rheumatoid arthritis. Two orally effective agents, the IL-1β-converting enzyme inhibitor and the mitogen-activating protein kinase p38 inhibitor, are currently being investigated in clinical trials.
Disease Management: What Have We Learned So Far?
Authors: Rubin Robert J. , Shapiro Jennifer R. , Hines Scott J. , Carroll Caitlin E.
Published: April 2003

Disease management (DM) is becoming an increasingly important tool for use in end-stage renal disease (ESRD). The goal of a DM program is to offer a continuum of care that uses guidelines and case management protocols to prevent acute care episodes, achieve improved outcomes and reduce health care costs. This article reviews the theory behind DM, describes key components of DM programs and explains the financial incentives for DM in ESRD. Of key importance in the increasing role of DM for ESRD has been the development of nationally recognized guidelines, the effects of which are now beginning to emerge. At the same time, recent studies have identified targeted opportunities for DM programs to improve outcomes and costs, including anemia management, dialysis dose, and vascular access. DM, through the use of guidelines and targeted toward these and other areas, has the potential to significantly impact the quality of care provided to ESRD patients.
Changes in Heart Rate Variability in Chronic Uremic Patients during Ultrafiltration and Hemodialysis
Authors: Galetta Fabio , Cupisti Adamasco , Franzoni Ferdinando , Morelli Ester , Caprioli Raffaele , Rindi Paolo , Barsotti Giuliano
Published: April 2003

Background: The analysis of heart rate variability (HRV) is a useful tool to evaluate cardiac autonomic modulation, which is frequently impaired in chronic uremia. Aims: The aim of this study was to evaluate HRV in chronic uremics and to separately investigate the acute changes induced by volume depletion and solute removal during a hemodialysis session. Methods: Fourteen uremic patients (8 males and 6 females, aged 50 ± 15 years) on maintenance hemodialysis and 14 sex- and age-matched healthy controls were studied. Both groups underwent ambulatory electrocardiogram monitoring to evaluate the HRV time and frequency domain indices. The hemodialysis session was performed by 1 h of high-rate isolated ultrafiltration followed by 3 h of bicarbonate diffusive procedure. Results: In uremic patients, the overall variability in the frequency [low-frequency power (LF): 505 ± 473, vs. 1,446 ± 654; high-frequency power (HF): 133 ± 162 vs. 512 ± 417; p < 0.001] and time domain indices (standard deviation of normal R-R intervals: 101.9 ± 33.3 vs. 181.7 ± 44.1 ms; p < 0.001) was markedly reduced compared to controls, whereas mean heart rate (83 ± 12.4 vs. 60.9 ± 8.8 bpm; p < 0.001) and LF/HF ratio (5.8 ± 3.5 vs. 2.2 ± 0.8; p < 0.001) were increased. Isolated ultrafiltration produced a marked further decrease in HRV indices, but the subsequent diffusive hemodialysis procedure, with a low ultrafiltration rate, made HRV increase again. Conclusions: Chronic uremics showed abnormal autonomic modulation with sympathetic-vagal imbalance. The unbalanced hypersympathetic response to body fluid depletion is related to the ultrafiltration rate. Low interdialytic weight gain and a low ultrafiltration rate, associated with adequate hemodialysis, should be the preferable strategy for uremic patients with autonomic dysfunction.
Long-Term Outcome of Permanent Hemodialysis Catheters: A Controlled Study
Authors: Jean Guillaume , Charra Bernard , Chazot Charles , Vanel Thierry , Terrat Jean-Claude , Hurot Jean-Marc
Published: April 2003

Aims: Hemodialysis tunneled catheters are widely used nowadays. However, their complications, infection and dysfunction, remain much too frequent. Different types of tunneled silicone hemodialysis catheters are available. We prospectively compared the long-term outcome of the two most popular devices, Permcath cuffed double catheter and TwinCath uncuffed twin catheter, both inserted percutaneously. Methods: From January 1994 to April 1998, 125 tunneled catheters were inserted in the internal jugular vein of 86 chronic hemodialysis patients, 63 TwinCath MedComp® (TC) and 62 Permcath Quinton® (PC). They were prospectively followed looking for technical patency, infection and dysfunction rate. Results: TC were used more often for iterative access (52 vs. 25% , p = 0.01) and were inserted more frequently in the left internal jugular vein (59 vs. 16% p < 0.001). Their median technical survival rate was longer (869 vs. 433 days for PC, p < 0.01) with a 1-year patency rate of 80 vs. 53% (p = 0.002). Total catheter extrusion was also slightly less frequent with TC (4.7 vs. 9.6%), but partial extrusion happened more frequently (43 vs. 16%, p = 0.02). No significant difference in infection rate was observed, 0.77 for TC vs. 1.3 local infection/1,000 catheter days; 1.08 vs. 1.30 bacteremia/1,000 catheter days. A persistent catheter thrombosis was observed in 7.9 vs. 20.9% in PC (p = 0.04), the number of dysfunction was 10.5 vs. 24/1,000 days in use (p = 0.0001) and the number of urokinase infusion was 4.4 vs. 12/1,000 days (p = 0.001). PC needed more radiological interventions for dysfunction with endolumenal brushes (4 vs. 0) or fibrin sleeve removal (4 vs. 0). The vena cava thrombosis incidence was not different (2 vs. 3). Conclusion: Although the study was not randomized, TC appears more efficient allowing for a longer patency with a lower dysfunction rate than PC. This was reinforced by less favorable conditions of TC including more left jugular side and more iterative catheters. The cuff does not offer a better bacteriological barrier or protection against extrusion, and the TC seems at a less risk of fibrin sleeves. However, a large randomized study is needed to definitively conclude.
Prevention of Hemodialysis Catheter-Related Bloodstream Infection Using an Antimicrobial Lock
Authors: Quarello Francesco , Forneris Giacomo
Published: April 2003

Among currently available vascular access options for hemodialysis, central venous catheters show the poorest reliability, with frequent complications of thrombosis and stenosis impairing patency. The most serious problem, however, is catheter-related bloodstream infection (CRBI), which is typically a cause for removal of the catheter and protracted systemic antibiotic therapy. In our experience, a totally implanted device (Dialock®, Biolink Corp.) seems to confer a better global protection against catheter-related infections than standard tunneled catheters, accounting for 0.97 vs. 4.75 infection episodes/1,000 catheter-days, respectively (p < 0.001). Bloodstream infection rates, however, are not statistically different in the two groups (0.85 vs. 0.81 per 1,000 catheter-days; p = n.s.), indicating that the improvement is mainly related to local cutaneous infections. On the other hand, in the Sodemann experience, a new taurolidine-based lock solution (Neutrolin®, Biolink Corp.) greatly reduced CRBI rates with both subcutaneous ports and tunneled catheters to 0.29 and 0.20 episodes/1,000 catheter-days, respectively. These promising results await further confirmation from ongoing clinical trials.
Importance of Periodontal Disease in the Kidney Patient
Authors: Craig Ronald G. , Spittle Margaret A. , Levin Nathan W.
Published: April 2003

End-stage renal disease (ESRD) patients on hemodialysis experience a greatly increased rate of atherosclerotic complications. In both hemodialysis and general populations, it has become evident that inflammation plays a central role in the pathogenesis of atherosclerotic complications. C-reactive protein (CRP), the major acute phase protein in man, has been found to predict all-cause and cardiovascular mortality in ESRD patients on hemodialysis maintenance therapy. Hepatic CRP synthesis is upregulated by proinflammatory cytokines released locally at sites of infection or inflammation, although many patients experience elevated CRP values in the absence of overt infection or inflammation. Destructive periodontal diseases in the general population have been associated with both an increased prevalence of atherosclerotic complications and an elevation in serum CRP values. In view of the prevalence of destructive periodontal diseases in the general population, and since periodontal evaluations are normally not performed as part of a medical assessment, destructive periodontal diseases may be an over looked source of inflammation in ESRD patients on hemodialysis therapy. The intent of this report is to review the possible role destructive periodontal diseases and associated periodontal infections may play in the management of the ESRD patient on hemodialysis maintenance therapy.
Sertraline Hydrochloride Treatment for Patients with Hemodialysis Hypotension
Authors: Yalcin Ahmet Uğur , Sahin Garip , Erol Mehmet , Bal Cengiz
Published: April 2003

Background: Recently some pathogenetic parallels have been drawn between dialysis-induced hypotension and disorders characterized by hemodynamic instability due to autonomic dysfunction, such as neurocardiogenic syncope and idiopathic orthostatic hypotension. Several studies have shown that central serotonergic pathways participate in the abnormal response, and selective serotonin reuptake inhibitors improve the symptoms of patients with neurocardiogenic syncope or idiopathic orthostatic hypotension. In order to evaluate the effectiveness of sertraline on dialysis-induced hypotension a prospective study was designed. Methods: The data of 9 patients from a 4-week pre-sertraline period were compared with the data of a 4-week sertraline (100 mg daily) period. The therapeutic effect of sertraline requires 4 weeks. Therefore the sertraline period was begun 4 weeks after starting the drug. Results: Post-hemodialysis weights and ultrafiltration volumes were similar in the pre-sertraline and sertraline periods. There were also no changes in hematocrit and serum albumin. Both systolic and diastolic blood pressure before dialysis remained unchanged during sertraline treatment. The nadir systolic blood pressure and systolic blood pressure after dialysis increased significantly in the sertraline period. The nadir diastolic pressure was also increased significantly but the increase in post-dialysis diastolic blood pressure did not reach statistical significance. The necessity of therapeutic interventions per dialysis session decreased significantly in the sertraline period compared with pre-sertraline period. Conclusions: This pilot study has shown that sertraline has the potential to be a safe and effective therapy for dialysis hypotension. Long-term clinical and pathophysiological studies are currently in progress.
Performance of Twin Central Venous Catheters: Influence of the Inversion of Inlet and Outlet on Recirculation
Authors: Level Claude , Lasseur Catherine , Chauveau Philippe , Bonarek Hervé , Perrault Luc , Combe Christian
Published: April 2003

Background: The use of a central venous catheter as a permanent vascular access is constantly growing. The recirculation rate in this type of vascular access varies depending on the site of insertion, the length of the catheter, the blood flow and the time elapsed since catheter insertion. When the in/out flow of the lumens of the catheter is reduced, it is sometimes necessary to inverse the arterial and venous lines of the catheter at the beginning or in the course of the dialysis session. The impact of such a practice on the recirculation rate has only been assessed by the low flow urea dilution method. Methods: The blood recirculation rate was measured using the ultrasound dilution velocity method (Transonic® system, Ithaca, N.Y.) in 14 patients (aged 64 ± 15 years), with a right internal jugular (n = 9) or right subclavian (n = 5) central catheter (Twincath, Medcomp®), used over a mean period of 16.3 (range 1–42) months. No clinical dysfunction of the catheter was apparently noted. The distance between the vein and the artery end of the catheter was 3.9 ± 2.8 cm, measured on chest radiography. The recirculation rate was measured over a single dialysis session at increasing blood flows in the normal and inversed position of the catheter. Results: The difference between the prescribed and effective blood flow was significant with an effective blood flow of 180± 16 ml/min for 200 ml/min, 264 ± 27 ml/min for 300 ml/min and 329 ± 16 ml/min for 400 ml/min prescribed blood flow. There was no relationship between the recirculation rate and blood flow whatever the position of the lines on the catheter. There was also no relationship between the recirculation rate and the distance between the catheter ends. However, reversing the catheter ends significantly increased the recirculation rates from 2.9 ± 5 to 12 ± 9% whatever the blood flow. Conclusion: The use of central catheters in an inversed position can result in a higher recirculation rate. Reversing the lines of the central catheters may lead to less effective hemodialysis and it seems particularly important for the nursing staff to be aware of this phenomenon. Thus, measurement of the effective blood flow and recirculation by ultrasound velocity should be included in quality monitoring and maintenance.
Acute-on-Chronic Liver Failure: Pathophysiological Basis of Therapeutic Options
Authors: Jalan Rajiv , Williams Roger
Published: April 2003

The vast majority of patients that are referred to a specialist hepatological centre suffer from acute deterioration of their chronic liver disease. Yet, this entity of acute-on-chronic liver failure remains poorly defined. With the emergence of newer liver support strategies, it has become necessary to define this entity, its pathophysiology and the short- and long-term prognosis. This review focusses upon how a precipitant such as an episode of gastrointestinal bleeding or sepsis may start a cascade of events that culminate in end-organ dysfunction and liver failure. We briefly review the pathophysiological basis of the therapeutic modalities that are available. Our current strategy for the management of liver failure involves supportive therapy for the end-organs with the hope that liver function would recover if sufficient time for such a recovery is allowed. Because liver failure, whether of the acute or acute-on-chronic variety, is potentially reversible, the stage is set for the application of newer liver-support strategies to enhance the recovery process.
Acid-Base and Electrolyte Management in Continuous Renal Replacement Therapy
Authors: Mehta Ravindra L.
Published: April 2003

Continuous renal replacement techniques are often utilized to manage acid-base and electrolyte problems in the critically ill patient. These techniques have an inherent capacity to manipulate the plasma composition and can be utilized efficiently to maintain homeostasis and metabolic control. Unfortunately, the efficacy of these techniques also permits wide variation in their use and can result in complications if they are not used appropriately. In most instances complications can be prevented by recognition of the operating principles and careful attention to detail. This article provides an overview of the principles of acid-base and electrolyte management with continuous renal replacement therapy.
Surfactant Lavage for the Management of Severe Meconium Aspiration Syndrome
Authors: Lam Barbara C.C.
Published: April 2003

Meconium aspiration syndrome (MAS) continues to be a major cause of morbidity and mortality in newborn infants. Recent studies on the pathophysiology of MAS showed that the meconium is more potent and toxic than we had previously appreciated. On the basis of animal experiences and a clinical pilot study, we propose that early tracheobronchial lavage with diluted surfactant is an effective and safe method for treatment of severe MAS.
Brain Single Photon Emission Computed Tomography at Term Age for Predicting Cerebral Palsy after Preterm Birth
Authors: Valkama A. Marita , Ahonen Aapo , Vainionpää Leena , Torniainen Pentti , Lanning Peter , Koivisto Maila
Published: April 2003

In order to assess the predictive value of neonatal brain perfusion with single photon emission computed tomography (SPET) with regard to neuromotor outcome at a corrected age of 18 months, 34 infants with birth weight <1,500 g and gestation age <34 weeks underwent brain technetium-99m ethylcysteinate dimer (99Tcm-ECD) SPET at term age. The perfusion defects were estimated by visual interpretation. Consecutive semiquantitative assessment was made in 26 cases and reference values for the tracer were collected from images of 17 preterm infants with normal outcome after the follow-up period. Relative regional cortical (frontal, sensorimotor, parietal and occipital), cerebellar and thalamic perfusion levels were evaluated in middle sagittal slices and hemispheric asymmetries in transaxial slices. Perfusion defects predicted cerebral palsy (CP) (n = 11) with 82% sensitivity, 70% specificity and 74% accuracy, the corresponding figures for ultrasound (US) being 73, 83 and 79%, respectively. The sensitivity of SPET in predicting moderate or severe CP (n = 7) was 100% and the specificity 67%, the corresponding figures for US being 71% and 74%, respectively. Brain SPET seems to identify the most severe forms of CP in preterm infants very well at term age, but cannot identify all mild ones. In addition to a low specificity, the radiation exposure restricts usefulness of the method for clinical purposes.
Brainstem Nitric Oxide Tissue Levels Correlate with Anoxia-Induced Gasping Activity in the Developing Rat
Authors: Gozal David , Torres José E.
Published: April 2003

Gasping is an important mechanism for survival that appears to be developmentally modulated by the glutamate-nitric oxide (NO) pathway. However, the temporal characteristics of NO brain tissue levels during gasping are unknown. We hypothesized that during anoxia-induced gasping, the gasping frequency would be closely correlated with caudal brainstem tissue NO concentrations in developing rats. Brainstem and cortical tissue NO levels were measured during anoxia using a voltammetric electrode in adult rats and 5-day-old pups during control conditions and following pretreatment with the NMDA receptor antagonist MK-801 (1 mg/kg) or the neuronal NO synthase inhibitor 7-nitro-indazole (7-NI; 100 mg/kg). In young animals, NO tissue levels followed a triphasic trajectory coincident with gasp frequency which was markedly altered by MK-801 and 7-NI, albeit with preservation of gasp frequency-NO tissue level relationships. In adult rats, 40-fold higher NO tissue levels occurred and followed a monophasic trajectory coincident with gasp patterning. In the cortex, monophasic increases in NO levels occurred at all ages. We conclude that anoxia-induced gasping neurogenesis is modulated via NMDA-NO mechanisms in the developing rat. We postulate that higher NO brainstem concentrations may favor early autoresuscitation, but limit anoxic tolerance.
Decreased Expression of L-Selectin on Peripheral Blood Polymorphonuclear Leukocytes in Neonates with Severe Asphyxia
Authors: Hashimoto Masaki , Nishida Akira , Minakami Hisanori , Takashima Yukio , Kato Masahiko , Okada Yasunori , Ogawa Yunosuke , Itoh Susumu , Kimura Hirokazu
Published: April 2003

The expression of adherent leukocyte surface molecules, L-selectin (CD62L), and Mac-1 (CD11b/CD18) in peripheral blood polymorphonuclear leukocytes (PMNs) was studied in 48 neonates and 24 healthy adults using fluorescence flow cytometry. L-selectin expression was decreased significantly in neonates, especially those with severe asphyxia (n = 10) compared with adults. Mac-1 expression was significantly increased in neonates compared with adults, but did not differ between 24 normal neonates, 14 neonates with mild asphyxia, and 10 neonates with severe asphyxia. These results suggest that the magnitude of the decrease in L-selectin expression reflects the severity of asphyxia in neonates.
Phenylethanolamine N-Methyltransferase-Immunoreactive Neurons in the Medulla oblongata of the Pigeon (Columba livia) Projecting to the Hypothalamic Paraventricular Nucleus
Authors: Marino-Neto J. , Armengol J.A.
Published: April 2003

The distribution and ascending projections to the hypothalamic paraventricular nucleus of phenylethanolamine N-methyltransferase (PNMT)-immunoreactive perikaria were studied in adult pigeons using a combination of retrograde transport of Fluorogold injected into the paraventricular nucleus, and double immunohistochemical procedures for PNMT, tyrosine hydroxylase and neuropeptide Y. PNMT-immunoreactive cell bodies were found in the subtrigeminal reticular nucleus of the ventrolateral medulla and in the nucleus of the solitary tract, mainly in the subnuclei: medialis superficialis, pars posterior, and medialis ventralis, pars posterior. PNMT-immunoreactive perikaria were also tyrosine hydroxylase immunoreactive, and are located within the rostral tyrosine hydroxylase immunoreactive cell groups of these areas. No perikaria double-labeled for neuropeptide Y and PNMT were found. Retrograde labeled cell bodies were observed in the subtrigeminal reticular nucleus and in the nucleus of the solitary tract. PNMT-immunoreactive retrogradely labeled cells were mainly observed in the subtrigeminal reticular nucleus. These data suggest the presence in the pigeon of medullary adrenergic cell groups partially comparable to mammalian C1 and C2 groups. Comparison of these results with data previously obtained in amphibians and reptiles suggests that the presence of a hypothalamically-projecting C1-like group might be a plesiomorphic medullary attribute in amniotes, whereas the variable presence of C2 and C3-like groups, as well as the content of NPY in the putative adrenergic perikaria, seem to be species-specific.
Sexually Dimorphic Expression of Glutamate Decarboxylase mRNA in the Hypothalamus of the Deep Sea Armed Grenadier, Coryphaenoides (Nematonurus) armatus
Authors: Trudeau V.L. , Bosma P.T. , Collins M. , Priede I.G. , Docherty K.
Published: April 2003

Glutamate decarboxylase (GAD), is a key enzyme in the central nervous system (CNS) that synthesizes the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) from glutamate. Our previous phylogenetic studies on the evolution of this enzyme indicates that there are at least two distinct forms: GAD65 and GAD67. They are the products of separate genes and probably derive from a common ancestral GAD gene following gene duplication prior to the emergence of the teleosts more than 200 Myr ago. Furthermore, a third GAD-like molecule, GAD3, discovered in the armed grenadier, Coryphaenoides (Nematonurus) armatus, is equally divergent from both GAD65 and GAD67. Specimens of C. (N.) armatus were collected by trawl at a depth of 4,000 m in the Porcupine Seabight (Northeastern Atlantic), and brains dissected and frozen for RNA extraction. All three GAD forms are found in the cerebellum, telencephalon and hypothalamus. Semiquantitative PCR analysis showed that males and females have similar levels of expression of GAD67 and GAD3 in the tissues studied. Independent of the sex examined, the levels of expression of GAD65 and GAD67 in the cerebellum were approximately half that in the telencephalon. GAD3 levels were approximately 30% higher in the cerebellum than in either the telencephalon or hypothalamus. In contrast to GAD67 and GAD3, hypothalamic expression of GAD65 mRNA is 1.8 times higher (p < 0.05) in males than in females. These data indicate that the expression of GAD65, a key enzyme for the synthesis of GABA is sexually dimorphic in females and males of C. (N.) armatus.
Proliferation Zones in the Adult Brain of a Sequential Hermaphrodite Teleost Species (Sparus aurata)
Authors: Zikopoulos B. , Kentouri M. , Dermon C.R.
Published: April 2003

Teleost sex change is an important model to understand general principles of sexual differentiation and plasticity in the adult brain. The present study is the first to examine the proliferation zones in the adult brain of males, females and sex-changing individuals of a protandrous teleost species (Sparus aurata), by means of 5-bromo-2-deoxyuridine immunocytochemistry. Postnatal neurogenesis in the marine teleost brain was found in ventricular and subventricular areas of the brain that in most cases coincided with the embryonic proliferation zones. The molecular layer of corpus and valvula cerebelli exhibited the highest mitotic activity in the adult brain. High mitotic activity was observed in the hypothalamic, thalamic and telencephalic ventricular areas, as well as the dorsal and ventral rim of the optic tectum. Most of the labeled cells were elongated, indicating the initiation of migratory activity. There were no qualitative differences in the distribution of proliferation zones between the sex phases studied with the exception of the ventricular region of the dorsal hypothalamic area. Volume fraction analysis of the area occupied by the labeled cells suggested that this region included higher densities of newborn cells in the female animals. The proliferation pattern in the adult gilthead sea bream brain is in agreement with the hypothesis of the continuous generation of new cells in the teleost brain. Moreover, our data propose that cell proliferation differences possibly existing in the ventricular region of the dorsal hypothalamus between sexual phases, might be involved in central mechanisms of sexual plasticity in protandrous hermaphrodite teleosts.
A Comparative Study of Protein Kinase C-Like Immunoreactive Cells in the Retina
Authors: Caminos E. , Velasco A. , Jarrín M. , Lillo C. , Jimeno D. , Aijón J. , Lara J.M.
Published: April 2003

The present study is a morphological and quantitative analysis of protein kinase C-like immunoreactive (PKC-L ir) bipolar cells in the retinas of five different vertebrate species (chicken, tench, zebrafish, goldfish and rat). The morphology of PKC-L-ir bipolar cell axon terminals in fish differs significantly from those of chicken and rat retinas. Fish have bulky terminals whereas chicken and rat have their terminals in the form of small knob-shaped branches. In tench and goldfish, PKC-L-ir bipolar cells gradually decrease in size from the medial (i.e., in tench: mean ± SD soma area of 30.09 ± 5.98 µm2) to the peripheral (i.e., in tench: 19.93 ± 1.73 µm2) retinal regions. This is not observed in chicken, rat or zebrafish where there is more homogeneity in s oma and axon terminal sizes between different retinal regions. Except in chicken, cell density increases from the central (i.e., in tench: mean ± SD 1795.88 ± 242.35 cells/mm2) to the peripheral (i.e., in tench: 4295.41 ± 279.23 cells/mm2) retina. This study provides data that show relevant differences in the PKC-L-ir bipolar morphology and density among birds, fish and mammals. Moreover, these structural variations could mean not only differences in the cellular physiology, but also in the patterns of development and maintenance of the retina in each species.
Visual Responses of Neurons in the Pretectal Nucleus lentiformis mesencephali to Moving Patterns Within and Beyond Receptive Fields in Pigeons
Authors: Xiao Quan , Cao Peng , Gu Yong , Wang Shu-Rong
Published: April 2003

Large-field patterns are effective stimuli for eliciting visual responses from neurons in the pretectal nucleus lentiformis mesencephali of nonmammals. The present study shows that stimulation beyond the receptive field does not contribute to the visual responses of neurons in the nucleus lentiformis mesencephali in two respects. First, changes in the direction and velocity of motion beyond the receptive field did not affect the visual responses of the pretectal cells to motion within the receptive field. Second, time differences in the onset of stimulation within and outside the receptive field did not influence the visual responses of the pretectal cells to motion in the receptive field, implying that there may be no long-range interaction between the receptive field and its surrounding field. The present study also indicates that the pretectal cells are not only sensitive to the direction and velocity of motion, but also to the size and density of dots in a random-dot pattern moving through the receptive field. Taken together with previous studies, these results suggest that the receptive field of the pretectal cells within the nucleus lentiformis mesencephali is large in size but well defined in boundaries, and that the pretectal cells respond to motion of visual stimuli within but not beyond their receptive fields.
Species Differences and Similarities in the Fine Structure of the Mammalian Corpus callosum
Authors: Olivares Ricardo , Montiel Juan , Aboitiz Francisco
Published: April 2003

A cross-species ultrastructural study of the corpus callosum was performed in six domestic species: the rat, the rabbit, the cat, the dog, the horse and the cow. The results indicate cross-species conservatism in callosal fiber composition with a good interspecies relation between fiber number and brain size. Across species, increases in both brain size and callosal area indicate more callosal fibers, although less than expected from the estimated increase in cortical cell number. Within each species, the correlation between fiber number and brain weight tends to disappear, although in most cases a larger callosum implies a larger number of callosal fibers. The median fiber diameter was conservative across species (0.11–0.2 µm), indicating the maintenance of conduction velocity of most callosal fibers regardless of interhemispheric distance. Nevertheless, the maximal fiber diameters tended to be higher in species with larger brains. Therefore, there is a population of coarse-diameter fibers that tend to increase their diameter and conduction velocity with increasing brain size. However, allometric calculations suggest that the associated increase in velocity in these large fibers may not be sufficient to maintain a constant interhemispheric transmission time in different species.
Brain Mediation of Anolis Social Dominance Displays
Authors: Baxter Jr Lewis R.
Published: April 2003

Measures of serotonin (5-HT) turnover in A. carolinensis forebrain increase acutely when males exhibit dominant social/territorial display routines, but decrease during submissive displays [Baxter et al., 2001a, b]. The present investigation sought to determine whether a difference in presynaptic regulatory receptors – one that might affect 5-HT flux – distinguish dominant vs. submissive anoles. Both 5-HT1B and 5-HT1D receptors are presynaptic regulators of output; this role is prominent at 5-HT terminals, where stimulation inhibits 5-HT release. Here, 3H-sumatriptan binding at sites similar to mammalian 5-HT1B/D receptors was significantly higher in forebrain regions of submissive anoles than in dominant cagemates; this receptor site seemed pharmacologically more like a 5-HT1B than a 5-HT1D receptor. Higher densities of presynaptic 5-HT1B receptors in subordinates than in dominants might account for differences in 5-HT flux (lower in subordinates than in dominants) observed in displaying anoles of different status. Knockout mice missing the 5-HT1B receptor show heightened male territorial aggressiveness, thus similar 5-HT regulatory mechanisms might influence the likelihood of dominance in both mammals and reptiles.