bluuebunny/crossref_metadata_2025 huggingface dataset:
Side‐effects and Complications in Large‐bore Catheters for Apheresis
Authors: Bambauer Rolf , Schneidewind‐Müller Jana‐Maria , Schiel Ralf , Latza Reinhard
Published: May 2003

Abstract:  Vascular catheters have become essential tools for management of hospitalized or chronically ill patients requiring intensive medical treatments such as extracorporeal detoxification procedures. The increased use of such devices has been accompanied by a corresponding increase in complications, such as bloodstream infection and thrombosis. In a retrospective study 332 large bore catheters which were inserted in 182 patients in the inferior or superior vena cava were investigated. The complication rate was in internal jugular vein puncture (N = 231) with 20% low and in the subclavian vein puncture (N = 94) with 60.5% and in the femoral vein puncture (N = 7) with 57.1% very high. The majority of complications were puncture not possible, puncture of the artery, abscess, septicemia, bleeding and thrombosis. To minimize the complication rate the surface of some catheters were treated and the microdomain structured surface inserted. The first results are very encouraging and should help to make large bore catheters safer.
Indications of Plasma Exchanges for Systemic Vasculitides
Authors: Guillevin Loïc , Pagnoux Christian
Published: May 2003

Abstract:  Indications of plasma exchanges for systemic vasculitides are well delineated according to the results of therapeutic trials undergone during the past decades. In combination with antiviral agents and/or immunosuppressants, plasma exchanges appear to be essential in the treatment of HBV‐related polyarteritis nodosa; pauci‐immune glomerulonephritis, kidney‐limited or as a feature of Wegener's granulomatosis or microscopic polyangiitis; Goodpasture's syndrome, and for some complications of cryoglobulinemia. In patients with HIV and HBV‐associated vasculitides, for which immunosuppressants are deleterious, plasma exchanges are also helpful and have been shown to be effective, combined with an antiretroviral regimen. In polyarteritis nodosa without HBV infection, Wegener's granulomatosis, Churg–Strauss syndrome and in other systemic diseases vasculitides, plasma exchanges can help to control or attenuate the disease. We review herein these indications of plasma exchanges in the light of the results of major trials.
Continuous Subcutaneous Insulin Infusion in Patients with Diabetes Mellitus
Authors: Schiel Ralf
Published: May 2003

Abstract:  During the last quarter of a century continuous subcutaneous insulin infusion (CSII) with external portable insulin pumps has been increasingly used in selected type 1 diabetic subjects and also in some patients with type 2 diabetes mellitus. The treatment of diabetes mellitus with insulin pumps has become more and more popular and accepted by diabetic patients as well as by medical professionals worldwide. Published trials have shown that, in most patients, mean blood glucose concentration and glycated hemoglobin (HbA1c) percentages are either slightly lower or similar on CSII versus an optimized therapy with multiple daily insulin injections. Hypoglycemic episodes seem to be less frequent and ketoacidoses occur at a comparable rate to that during intensive injection therapy. Moreover, nocturnal glycemic control can be improved with insulin pumps, and automatic basal rate changes help to minimize a prebreakfast blood glucose increase (often called ‘the dawn phenomenon’). For many patients, CSII provides greater flexibility in timing of meals with the result of better quality of life and higher treatment satisfaction. However, despite these promising data, and although many patients with diabetes mellitus with well‐defined clinical problems are likely to benefit substantially from CSII, either in respect to glycemic control, acute complications or quality of life and treatment satisfaction, we are still far away from reaching ‘dream diabetes management’, the fully automatic closed‐loop system. Presently, the most difficult problem concerns not the design of an ‘optimal’ insulin pump, but rather the development of a system which is able to provide continuous and reliable blood glucose monitoring. Hence, because this problem has not been solved with maximum satisfaction, the development of a feedback‐controlled ‘artificial pancreas’ is one of the main goals in diabetes management in the new millennium.
Vascular Access for Apheresis in Intensive Care Patients
Authors: Schönermarck U. , Bosch T.
Published: May 2003

Abstract:  In the intensive care unit, apheresis therapy (including plasma exchange, selective immunoadsorption and –affinity and detoxification by hemoperfusion) is limited to certain disease entities. Temporary insertion of large‐bore central venous catheters is necessary for efficient performance of apheresis therapy. The choice of the optimal catheter insertion site (femoral, subclavian or internal jugular vein route) depends on the individual situation, the experience of the operator and the anticipated treatment period. Morbidity and mortality of the patients concerned can be substantially increased by insertion and use of central venous catheters. Early and delayed complications are briefly discussed. Appropriate selection of the catheter insertion site, the catheter type, strictly aseptic insertion procedures and optimal care of catheter and insertion site are essential to avoid complications.
Immunoadsorption in Systemic Lupus Erythematosus: Different Techniques and their Current Role in Medical Therapy
Authors: Gaubitz Markus , Schneider K. Matthias
Published: May 2003

Abstract:  In the last 30 years, several studies have documented the effect of plamapheresis and immunoadsorption in eliminating pathogenic autoantibodies (AB) and immune complexes (IC) from circulation of patients with systemic lupus erythematosus (SLE). However, these extracorporeal therapies are still not accepted as first line options, which may be because of existing controlled studies failing to confirm any obvious benefit. Immunoadsorption offers some advantages compared with plasmapheresis, but until today only the avoidance of any substitution fluids has really been used. The new therapeutic options given by immunoadsorbers—a continuous application in acute disease states or chronic use instead of immunosuppressive drugs—have still to be evaluated in systemic autoimmune diseases. To date published studies of immunoadsorption in patients with SLE reveal good efficacy in a majority of patients combined with excellent biocompatibility. Randomized controlled trials are mandatory to give continued support to the therapeutic opportunities offered only by immunoadsorption; the limited number of patients suitable for this therapy necessitates multicentric cooperation.
Dilatation and Declotting of Arteriovenous Accesses
Authors: Turmel‐Rodrigues Luc
Published: May 2003

Abstract:  The autogenous arteriovenous fistula has long been proven to be the most durable access for hemodialysis and therefore for any therapy based on plasma exchange. Forearm autogenous fistulas are, however, frequently challenging to create, leading less experienced surgeons to create elbow fistulas or even worse, to place prosthetic grafts. Once the arteriovenous access is constructed, stenoses largely located on the venous side frequently occur, leading to thrombosis if they are not detected and preventively treated. Interventional radiology is now the first line and preferred treatment in the majority of cases of vascular access dysfunction. The overall advantages compared with conventional surgery are its minimal invasiveness, better preservation of the patient's venous reserve, and better outcomes for selected indications such as thrombosed autogenous fistulas. Prophylactic dilation of stenoses greater than 50% associated with clinical abnormalities such as flow‐rate reduction is warranted to prolong access patency. Stents are placed only in selected cases with clearly insufficient results of dilation but they must never overlap major side veins and obviate future access creation. Thrombosed fistulas and grafts can be declotted by purely mechanical methods or in combination with a lytic drug. The success rates are over 90% for dilation, in central veins radiologists frequently resort to the use of stents. Long‐term results after dilation in the largest series are better in forearm native fistulas compared with grafts. The initial success rates for declotting are better in grafts compared with forearm fistulas but early rethrombosis is frequent in grafts so that primary patency rates can be better for native fistulas from the first month's follow‐up.
Correcting Immune Imbalance: The Use of Prosorba Column Treatment for Immune Disorders
Authors: Levy Joshua , Degani Nurit
Published: May 2003

Abstract:  The treatment of selected refractory autoimmune diseases has been complemented by the use of Protein A (Prosorba column) immunoadsorption. US Food and Drug Administration‐approved clinical applications include idiopathic thrombocytopenia purpura (ITP) and rheumatoid arthritis (RA). Other common off label uses include thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS). Less common experimental uses in diseases in which efficacy has been reported include autoimmune CNS syndromes, peripheral neuropathies, autoimmune pancytopenia, hemolytic anemia and solid organ transplant rejection. Prosorba column treatment is generally well tolerated but a small proportion of treated patients experience chills, fever, tremor, hypotension and rash. The mechanism of action suggested for the efficacy of the column is the restoration of normal immune balance and normal tolerance. Observations in ITP has suggested that column treatment stimulates a rise in anti‐idiotype antibody directed against antiplatelet antibodies, effecting a decrease in pathogenic antiplatelet antibodies and immune complexes.
Therapeutic Plasma Exchange: An Underutilized Therapeutic Modality?
Authors: Pepkowitz Samuel H. , Ziman Alyssa
Published: May 2003

Abstract:  Since its clinical availability approximately 25 years ago, therapeutic plasma exchange (TPE) has become recognized as appropriate primary therapy for many diverse medical conditions. In some aspects TPE has been constrained in its use according to schedules of efficacy. Expansion of TPE to other indications is likely once attention is focused on its ability to enable patients to avoid potentially toxic pharmacologic interventions if employed as a chronic therapy, and especially when it is accepted that adjunctive use, not only a curative role, is a valuable use of this therapeutic modality.
Time Course of Postoperative Recovery of N‐Acetyl‐Aspartate in Temporal Lobe Epilepsy
Authors: Serles W. , Li L. M. , Antel S. B. , Cendes F. , Gotman J. , Olivier A. , Andermann F. , Dubeau F. , Arnold D. L.
Published: May 2003

Purpose: To assess the time course of increases in N‐acetyl‐aspartate/creatine (NAA/Cr), which can be measured using proton MR spectroscopic imaging (1H‐MRSI), in patients with intractable nonlesional temporal lobe epilepsy (TLE) after successful epilepsy surgery.

Methods: We performed pre‐ and postoperative 1H‐MRSI in 16 seizure‐free (SF) patients and 16 not seizure‐free (NSF) TLE patients. We calculated a mixed‐design analysis of variance (ANOVA) between SF and NSF groups, ipsi‐ and contralateral to the side of operation, and pre‐ and postoperative NAA/Cr measurements. We applied nonlinear regression between pre‐ and postoperative NAA/Cr differences and the time interval between 1H‐MRSI scans to fit a negative exponential model to NAA recovery.

Results: Mixed‐design ANOVA revealed that (a) postoperative NAA/Cr was significantly higher in SF than in NSF patients (p = 0.02) and that (b) in the SF group, postoperative NAA/Cr values were significantly higher than preoperative values (p <0.05) and returned to the normal range in most patients. According to our nonlinear regression model, in SF patients, there was a 50% increase relative to preoperative NAA/Cr values after 5.8 months, whereas an improvement of 95% was reached after 25 months.

Conclusions: Our results extend preliminary observations of postoperative NAA recovery of SF patients by characterizing the time course of recovery as an exponential function with a half‐time of ∼6 months. The reversal of neuronal metabolic dysfunction remote from the epileptic focus may underlie the clinical observation of improvement of cognitive dysfunction after successful epilepsy surgery.
Focal Functional Deficits in Temporal Lobe Epilepsy on PET Scans and the Intracarotid Amobarbital Procedure: Comparison of Patients with Unitemporal Epilepsy with Those Requiring Intracranial Recordings
Authors: Salanova V. , Markand O. , Worth R.
Published: May 2003

Purpose: To analyze the relationship between the intracarotid amobarbital procedure (IAP) and positron emission tomography (PET) and study the lateralizing value of these tests in patients with unitemporal epilepsy and those requiring intracranial recordings.

Methods: We compared 51 patients with unitemporal epilepsy (group 1) with 26 patients in whom surface recordings failed to reveal a distinct unitemporal focus, necessitating invasive recordings (group 2).

Results: The brain magnetic resonance imaging (MRI) scans for group 1 showed mesial temporal sclerosis in 70.5% of the patients. PET showed unilateral temporal hypometabolism in 88%. In addition, 74.5% of the patients in group 1 had impaired memory on the epileptogenic side on the IAP, and 89.4% of those patients also had ipsilateral temporal hypometabolism on PET scans. All the group 1 patients underwent temporal resections. The pathologic examination showed hippocampal sclerosis in 72% of the patients. Eighty percent of group 1 patients became seizure free, and 16% had rare seizures (follow‐up, 2–7 years). MRIs for group 2 showed mesial temporal sclerosis in 31% of the patients; PET scans showed temporal hypometabolism in 39%. The IAP was lateralized in 47.8%. Sixty‐nine percent had temporal lobe resections. The pathologic examination showed hippocampal sclerosis in 44% of the patients. Forty‐four percent of group 2 patients became seizure free, and 27.7% had rare seizures (follow‐up, 2–8 years).

Conclusions: Ninety‐six percent of the patients with unitemporal foci had focal functional deficits on the epileptogenic side on 18‐fluorodeoxyglucose‐(FDG) PET scans, the IAP, or both. The results of the FDG‐PET were predictive of impaired memory on the IAP. Memory impairment contralateral to the temporal hypometabolism found on the PET scans was never seen. These patients had an excellent outcome. In contrast, < 50% of the patients requiring intracranial recordings had focal functional deficits, suggesting that more a diffuse pathology may account for their less favorable outcome.
Genetic Predisposition to Severe Myoclonic Epilepsy in Infancy
Authors: Benlounis A. , Nabbout R. , Feingold J. , Parmeggiani A. , Guerrini R. , Kaminska A. , Dulac O.
Published: May 2003

Purpose: To address genetic predisposition to febrile convulsions (FCs) and epilepsy as an etiologic back‐ground of severe myoclonic epilepsy in infancy (SMEI).

Methods: Familial antecedents of epilepsy and FCs were analyzed in four groups of patients with SMEI (65 cases), FCs (57 cases), childhood absences (67 cases), and a control group of patients with no neurologic problems (64 cases).

Results: Patients with SMEI and those with FCs had significantly increased incidence of FCs in their relatives compared with those with absence epilepsy and with the control group. The incidence of epilepsy in relatives of patients with SMEI and absence epilepsy was increased compared with that in the control group and reached statistical significance. Epilepsy in relatives with SMEI had the characteristics of idiopathic generalized epilepsy.

Conclusions: A genetic predisposition could determine three types of epileptic syndromes: FCs, idiopathic generalized epilepsy, and SMEI.
Circulating Levels of Allopregnanolone, an Anticonvulsant Metabolite of Progesterone, in Women with Partial Epilepsy in the Postcritical Phase
Authors: Galli Renato , Luisi Michele , Pizzanelli Chiara , Monteleone Patrizia , Casarosa Elena , Iudice Alfonso , Murri Luigi
Published: May 2003

Purpose: Several lines of evidence indicate that there exists a relation between ovarian hormones and epilepsy. Estrogens decrease seizure threshold and increase brain excitability, whereas progesterone has an inhibitory effect and reduces epileptiform activity. Recently considerable interest has turned to neuroactive steriods, a group of progesterone metabolites, as endogenous modulators of excitability of the central nervous system (CNS). Their ability to alter neuronal firing rapidly occurs through interaction with γ‐aminobutyric acid (GABA) A receptor complex. In a previous experience, serum allopregnanolone (3α‐OH‐5α‐pregnan‐20‐one) levels were measured in 15 women with partial epilepsy in the intercritical phase, and no significant differences were found between patients and control subjects.

Methods: To find out if there are changes in serum allopregnanolone levels after epileptic seizure, blood samples were drawn immediately, 15 min, and 6 h after a seizure in seven fertile females with partial epilepsy.

Results: The most interesting finding is that allopregnanolone increases in serum during the first 15 min after partial seizures (p <0.05) and decreases after 6 h.

Conclusions: These data are consistent with a role for allopregnanolone in the control of neuronal excitability and seizures.
Alfentanil‐Induced Epileptiform Activity: A Simultaneous Surface and Depth Electroencephalographic Study in Complex Partial Epilepsy
Authors: Ross J. , Kearse L. A. , Barlow M. K. , Houghton K. J. , Cosgrove G. R.
Published: May 2003

Purpose: Alfentanil is a high potency mu opiate receptor agonist commonly used during presurgical induction of anesthesia. This and other opiate receptor agonists have demonstrated proconvulsant effects in animals, but these properties have been less consistently demonstrated in humans. Most human scalp EEG studies have failed to demonstrate induction of epileptiform activity with these agents, which is inconsistent with findings using intracranial EEG. Simultaneous scalp and depth EEG recordings have yet to be performed in this setting. The relationship between opiate dose and proconvulsant activity is unclear.

Methods: Simultaneous scalp and depth electrode recordings were performed on five patients with complex partial epilepsy (CPE) who underwent alfentanil anesthesia induction before depth electrode removal. Consecutive equal bolus doses of alfentanil were administered to each patient according to strict time intervals so as to assess their correlation with any induced epileptiform activity.

Results: Epileptiform activity was induced by alfentanil in three of five patients. Two of these patients had electrographic seizures. Epileptiform activity was only detected from the depth electrodes, occurring within 2 min of the first bolus dose in all three cases. Further increase or spread of epileptiform activity did not occur despite cumulative bolus doses of alfentanil.

Conclusions: Alfentanil is proconvulsant in patients with CPE. Induced seizures may be subclinical and lack a scalp EEG correlate. There is a complex dose—response relationship. Alfentanil induction of anesthesia should be approached with caution in patients with CPE.
Antiepileptic Drug Withdrawal in Patients with Temporal Lobe Epilepsy Undergoing Presurgical Video‐EEG Monitoring
Authors: Yen Der‐Jen , Chen Chien , Shih Yang‐Hsin , Guo Yuh‐Cherng , Liu Li‐Ting , Yu Hsiang‐Yu , Kwan Shang‐Yeong , Yiu Chun‐Hing
Published: May 2003

Purpose: To investigate antiepileptic drug (AED) withdrawal during video‐EEG monitoring in adult patients with temporal lobe epilepsy (TLE).

Methods: Between 1995 and 1997, 102 consecutive patients with refractory TLE were admitted to the epilepsy monitoring unit for presurgical evaluation. Patients were monitored with ongoing AEDs being rapidly decreased and discontinued in 4–6 days. The monitoring was continued until sufficient numbers of seizures were recorded. Serum AED levels were checked at admission and after the first complex partial seizure (CPS).

Results: In all, 89 patients had 429 CPSs (mean, 4.8 per patient), including 156 (36.4%) secondarily generalized. A mean of 153.8 h (16–451 h) was required for completing the monitoring in each patient. Forty‐three (48.3%) patients experienced seizure clusters, and eight (9.0%) had generalized seizures that had never occurred or had been absent for years. However, none evolved to status epilepticus. Carbamazepine was the most commonly used AED in 71.9% of patients, followed by valproate and phenytoin. When the first CPS occurred, mean 77.2 h since the beginning of the monitoring, serum levels of these three AEDs were mostly subtherapeutic rather than minimal.

Conclusions: Acute AED withdrawal effectively provoked seizures in TLE patients undergoing presurgical video‐EEG monitoring. However, nearly 50% of patients had seizure clusters or secondarily generalized seizures. Serum AED levels were mostly subtherapeutic when the first CPS occurred.
Visual Field Loss Associated with Vigabatrin: Quantification and Relation to Dosage
Authors: Hardus P. , Verduin W. M. , Engelsman M. , Edelbroek P. M. , Segers J. P. , Berendschot T. T. J. M. , Stilma J. S.
Published: May 2003

Purpose: To describe the correlation between visual field loss and the duration, dosage, and total amount of vigabatrin (VGB) medication in a group of patients with epilepsy. Co‐medication of antiepileptic drugs (AEDs) and compliance were also studied.

Methods: Ninety‐two patients (53 male and 39 female) taking VGB medication in the past or the present, attending the Outpatient Epilepsy Clinic in Utrecht, were examined with the Goldmann perimeter. The amount of visual field loss was calculated by the Esterman grid method and by a new method, with which the percentage surface loss of the visual field is measured. A complete drug history was compiled, specifying the amount and duration of VGB medication. Concomitant AED medication was noted. Serum levels of AEDs were determined.

Results: Linear regression showed the total amount of VGB as the most significant parameter to predict visual field loss (p <0.001). Further, men were more affected than women (p = 0.026). Compliance was good, and other AEDs did not influence the results.

Conclusions: Because prolonged use of VGB medication is correlated with the amount of visual field loss, VGB should be prescribed only when there are no alternatives. In such cases, we recommend an examination of the peripheral visual field before starting therapy and a repeated examination every 6 months.
Mental Retardation in Pediatric Candidates for Epilepsy Surgery: The Role of Early Seizure Onset
Authors: Vasconcellos Elza , Wyllie Elaine , Sullivan Shawn , Stanford Lisa , Bulacio Juan , Kotagal Prakash , Bingaman William
Published: May 2003

Purpose: We sought to determine whether early age at seizure onset is a risk factor for mental retardation, independent of etiology. Assessment of risk for mental retardation with continued uncontrolled seizures plays a role in considerations of timing for epilepsy surgery. Previous studies have indicated that onset of seizures in the first years of life may be a risk factor for mental retardation, but the etiologies of the epilepsies were not included in the analyses.

Methods: Intellectual function was assessed at ages 2–20 years during presurgical evaluation in 100 patients with intractable epilepsy due to focal lesions limited to part of one lobe of the brain. Mental retardation (MR) was defined as Full‐Scale Intelligence Quotient (FSIQ) ≤70. The age at seizure onset and the seizure frequency were obtained retrospectively.

Results: Younger ages at seizure onset were associated with lower FSIQ scores, and mean FSIQ was also significantly lower for patients with onset of epilepsy at ≤24 months of age (74.0 ± 21.5) versus that in patients with onset of epilepsy later in life (87.8 ± 18.8: p = 0.005). The frequency of patients with MR was significantly higher for patients with seizure onset at ≤24 months of age (15 of 33, 46%) than for patients with seizure onset later in life (eight of 67, 12%; p <0.001). This difference persisted within etiologic subgroups. For patients with focal malformation of cortical development, MR was seen in eight (50%) of 16 patients with seizure onset at ≤24 months versus two (10%) of 20 patients with seizure onset at >24 months (p > 0.001); for patients with tumor, MR was seen in four (50%) of eight patients with seizure onset at >24 months versus four (13%) of 30 patients with seizure onset at >24 months (p = 0.003); and for patients with hippocampal sclerosis, MR was seen in two (28%) of seven patients with seizure onset at ≤24 months versus none of 30 patients with seizure onset at >24 months (NS). Within the subgroup with daily seizures. MR was present in 13 (65%) of 20 patients with seizure onset at >24 months versus five (17%) of 29 patients with seizure onset later in life (p =0.001).

Conclusions: These results indicate that onset of intractable epilepsy within the first 24 months of life is a significant risk factor for MR, especially if seizures occur daily. The risk based on early age at seizure onset appeared independent of etiology and persisted within subgroups of patients with focal malformation of cortical development, tumor, or hippocampal sclerosis. Prospective studies will be important to clarify whether early surgical intervention may reduce the risk for subsequent MR in carefully selected infants.
Ictal Perfusion Changes During Occipital Lobe Seizures in Infancy: Report of Two Serial Ictal Observations
Authors: Hollo Andras , Kaminska Anna , Véra Pierre , Cieuta Cecile , Ville Dorothée , Bulteau Christine , Dulac Olivire , Chiron Catherine
Published: May 2003

Serial‐ictal single‐photon‐emission computed to mography (SPECT) examinations are presented in two infants (ages 1 and 2 years), with early ictal and ictal in one, and ictal and late ictal images in the other. Both had pharmacoresistant occipital epilepsy, due to focal cortical dysplasia. In the first case, size of ictal hyperperfusion increased in the course of the seizure from early ictal to ictal state. A concomitant ictal hypoperfusion was observed around the hyperperfused area. In the second patient, there was a dramatic difference between ictal and late ictal images. In the late ictal state, the previous occipital ictal hyperperfusion and extraoccipital ictal hypoperfusion disappeared, together with homolateral posterotemporal and contralateral occipital hyperperfusion, corresponding to seizure propagation. Ictal extratemporal blood‐flow changes are therefore highly dynamic, particularly in very young children.
Generalized Convulsions After Consuming a Large Amount of Gingko Nuts
Authors: Miwa Hideto , Iijima Makiko , Tanaka Shigeki , Mizuno Yoshikuni
Published: May 2003

We report a 36‐year‐old woman, without any past or family histories of epilepsy, who presented frequent vomiting and generalized convulsions. About 4 h before the convulsion, she had consumed ∼70–80 gingko nuts, seeds of Gingko biloba, in an attempt to improve her health. It is important to know that conculsion may be induced if a large amount of gingko nuts is consumed. The neurotoxicity of gingko nuts, particularly their convulsion‐inducing effect, should be recognized.
Advancing Age and Cervical Cancer Screening and Prognosis
Authors: Sawaya George F. , Sung Hai‐Yen , Kearney Kathleen A. , Miller Marie , Kinney Walter , Hiatt Robert A. , Mandelblatt Jeanne
Published: May 2003

OBJECTIVES:

To determine associations between advancing age and screening behavior and prognosis in long‐term members of a prepaid health plan diagnosed with invasive cervical cancer (ICC).

DESIGN:

Case series.

SETTING:

Prepaid health plan.

PARTICIPANTS:

All women diagnosed with ICC at Kaiser Permanente Medical Care Program—Northern California health plan from 1988 to 1994.

MEASUREMENTS:

From medical records, we recorded participants' age, stage at diagnosis, tumor histology, and results of and reasons for all previous cervical smears. We limited our analysis to women who had been members of the health plan for at least 30 of the 36 months preceding diagnosis (n = 455).

RESULTS:

Women in older age groups were less likely than younger women to have been screened within the 3 years before diagnosis (P = .005 for trend). Nonadherence to follow‐up of abnormal cervical smears was uncommon (17/455, 3.7%) and not age related (P = .932 for trend). The proportions of ICC that were interval cancers, defined as ICC diagnosed within 3 years of a negative screening smear, were highest in women under age 30 (P = .004 for trend). In multivariate analyses controlling for stage at diagnosis, women age 60 and older were not more likely to die of ICC within 3 years of diagnosis than were women younger than age 60 (odds ratio 1.30, 95% confidence interval 0.75–2.28).

CONCLUSION:

The disproportionate burden of cervical cancer observed in older women appears to be largely attributable to lack of screening within the 3 years before diagnosis. J Am Geriatr Soc 49:1499–1504, 2001.
Theoretical investigation of the lower bend-stretch states of the Cl−H2 anion complex and its isotopomers
Authors: Alexander Millard H.
Published: May 2003

Coupled-cluster [CCSD(T)] calculations of the potential energy surface of the Cl−H2 complex were carried out, subsequently averaged over the vibrational motion of the H2 moiety and then fitted. The lower bend-stretch levels of the anion complex were then determined, for the H2 molecule in its ground and first excited vibrational levels. The resulting rotational constants agree with earlier experimental values, almost to within the experimental precision. The predicted dissociation energies are 5–8% larger than the experimentally derived values. The bend-stretch wave function of the lowest state of the Cl−oD2 complex encompasses a considerably larger range of bending motion than in the complexes with oH2 and pD2.
Magnetic properties of Fe thin films on Ag submicrometer islands
Authors: Yu C. C. , Cheng W. C. , Lee W. B. , Chen S. Y. , Liou Y. , Yao Y. D.
Published: May 2003

Face-centered-cubic Ag(100) submicrometer islands on an RCA-cleaned Si(100) substrate were fabricated by molecular beam epitaxy; a 500 Å Fe thin film was then grown onto Ag films at 100 °C. We experimentally demonstrate that the magnetic behavior of Fe films is strongly dependent on the thickness and morphology of the Ag underlayer. The Ag film, in order to reduce the surface free energy, forms isolated three-dimensional square islands with {111} sidewall on the Si(100) substrate. The average height, grain size and surface roughness of these Ag islands were tuned by varying the deposition thickness of the Ag film. The in-plane easy axis of the Fe film was rotated 45° while the thickness of the Ag underlayer reaches 100 Å and the Ag rough surface provides a source of domain wall pinning.
Chemical synthesis of narrowly dispersed SmCo5 nanoparticles
Authors: Gu Hongwei , Xu Bing , Rao Jiancun , Zheng R. K. , Zhang X. X. , Fung K. K. , Wong Catherine Y. C.
Published: May 2003

In this article we report a chemical synthetic means for generating a high Ku magnetic material—narrowly dispersed nanoparticles of SmCo5. Using Co2(CO)8 and Sm(acac)3 as the precursors under air-free conditions, we produced SmCo5 nanoparticles according to the procedure reported by Sun et al. [Science 287, 1981 (2000)] but with some modifications. The nanoparticles, with diameters of 6–8 nm, have a SmCo5 composition, as indicated by transmission electron microscopy, electron diffraction, and x-ray photoelectron spectroscopy. The magnetization measurement of the nanoparticles, exhibits superparamagnetism, which is blocked for temperatures below ∼110 K, suggesting Ku to be ∼2.1×106 erg/cm3 for the as-prepared particles.
Atomistic modeling of nanocrystalline ferromagnets
Authors: Zheng Guang-Ping , Gross Dirk , Li Mo
Published: May 2003

A model nanocrystalline ferromagnet is investigated at the atomistic level using numerical simulations. The nanocrystalline microstructure is constructed using methods of stochastic optimization and Voronoi construction. The atomic structure of the grains is obtained by molecular dynamics. Nanostructures obtained in this way are characterized by the log–normal grain size distribution and the coordination number of defects at grain boundaries. An Ising model is employed to model the magnetic properties of nanostructured cobalt films with strong perpendicular anisotropy. Particular attention is paid to the effects of the grain boundary structure. We consider J∼exp(−αr) on the grain boundary, where α is a parameter that represents grain boundary effects. The dependences of the Curie temperature, coercivity, and hysteresis loop on the grain-isolated parameter α are investigated.
Characterization of magnetization processes in nanostructured rare earth-transition metal films
Authors: Zheng Guang-ping , Zhan Yangwen , Liu Peng , Li Mo
Published: May 2003

We synthesize rare earth-transition metal (RE-TM) amorphous films using the electrodeposition method (RE=Nd, Gd and TM=Co). Nanocrystructured RE-TM films are prepared by thermal treatment of as-synthesized films below the glass–crystal transition temperature. Based on the magnetoelastic effect, the magnetization processes in nanostructured samples are characterized by acoustic internal friction measurements using the vibrating-reed technique. Since internal friction and the Young’s modulus are sensitive to grain boundary and magnetic domains movement, this technique seems to characterize the effects of nanostructures on the magnetization processes in RE-TM films well. We find that the magnetoelastic effect in nanostructured RE-TM film increases with an increase in grain size.
Nonuniform magnetic structure in Nd2Fe14B/Fe3B nanocomposite materials
Authors: Gao Youhui , Shindo Daisuke , Petford-Long Amanda K.
Published: May 2003

The magnetic structure of a Nd4Fe77Co3B16 two-phase nanocomposite is studied by Lorentz microscopy and electron holography in this article. The big domains consisting several grains show strong intergranular exchange interaction. Some bright spots inside domains reflect a nonuniform magnetic structure that is characterized as a magnetic vortex using electron holography. It results from the strong intergranular exchange interaction and the randomly oriented Nd2Fe14B particles. This nonuniform magnetic structure is extensive in two-phase nanocomposites, and has an important influence on the magnetic properties. The internal stray field is dramatically weakened because of the zero divergence of magnetization in the magnetic vortex, and small Neff is observed. With the numerical simulation, it is found that the formation of the magnetic vortex induces a concave demagnetization curve and decay of the coercivity. This is the reason why the coercivity of practical magnets deviates greatly from that of theoretical results.
Quantitative analysis of interface resistance in Co/Nb multilayers for normal and superconducting Nb
Authors: Lee S. F. , Huang S. Y. , Kuo J. H. , Lin Y. A. , Lin L. K. , Yao Y. D.
Published: May 2003

The thickness and magnetic field dependence of resistance in Co/Nb multilayers with current perpendicular to plane geometry were measured at 4.2 K. When the number of bilayers increased, the resistance increased linearly. This linear behavior enables us to use a series resistance model to analyze our data for the thicknesses we used, 20 and 80 nm for Nb. When sandwiched between Co, Nb is a normal metal when thinner than 30 nm, otherwise it is superconducting. Assuming bulk resistivities for normal Nb and Co, we got unit area resistance values of 6.3 and 3.5 fΩ m2 for superconducting and normal Nb/Co interfaces. There was no magnetoresistance observed, at a resolution of about 0.1%. The applicability of a diffusive regime model is discussed.
Extended multipole image of a nonideal permanent magnet rotor
Authors: Kildishev Alexander V. , Nyenhuis John A. , Zhilichev Yuriy N.
Published: May 2003

Reduction of the external magnetic field (magnetic signature) of large electric motors may be important in military and other applications. This article deals with critical issues in the design and manufacturing of permanent magnet (PM) motors that are responsible for increased magnetic signatures. Emphasis is on analysis of the nonidealities of PM rotors such as imbalances in the permanent magnet excitation system due to manufacturing tolerances and differences in material properties. Spatial harmonic analysis is used to describe the magnetic signature. The rotor simulation considers rectangular PM segments, and uses statistical characterization of possible nonidealities in dimensions, positioning, and magnetization. The approach focuses on lower degree magnetic multipole moments (dipolar, quadrupolar, and octupolar) in spheroidal and spherical domains, and is applied to PM inducing elements.
Comparison of Halbach magnetized brushless motors equipped with air-cored and iron-cored rotors
Authors: Xia Z. P. , Zhu Z. Q. , Jewell G. W. , Howe D.
Published: May 2003

The performance of Halbach magnetized brushless motors equipped with air-cored and iron-cored rotors is investigated theoretically and experimentally. It is shown that an optimal combination of magnet thickness and pole number exists for maximum air-gap flux density. By employing a rotor back iron, the air-gap field and hence the output torque can be enhanced significantly if the ratio of the radial thickness of the magnet to the pole pitch is small.
First principles determinations of magnetic anisotropy energy of Co nanoclusters
Authors: Hong Jisang , Wu R. Q.
Published: May 2003

We have calculated magnetic anisotropy energies of several free standing Co nanoclusters consisting of one, two, three, and six Co atoms with the full potential linearized augmented plane wave method. The magnetic moments are found to be aligned perpendicular to the Co–Co bond. The results show that the spin magnetic moments are suppressed by roughly 10% compared to Co monolayer or Co nanowire. Orbital magnetic moments and anisotropy energies depend sensitively on the size and shape of clusters.
Magnetic properties of [NdFeBx/Nbz]n multilayer films
Authors: Tsai Jai-Lin , Chin Tsung-Shune , Yao Yeong-Der , Melsheimer A. , Fisher S. , Drogen T. , Kelsch M. , Kronmüller H.
Published: May 2003

This article presents the systemic relationship between microstructure and magnetic properties of NdFeB single layer and [NdFeBx/Nbz]n multiplayer films. Temperature dependence on coercivity was fitted to a modified nucleation model to study the magnetization reversal process of films. The microstructure parameters (αK) determined the deteriorating effect of the microstructure on coercivity. The highest values of the single- and multilayer films were 0.46 and 0.69, respectively. It proved that the Nb spacer layer improved the grain boundary of the Nd2Fe14B matrix effectively.
Dynamic exchange coupling and Gilbert damping in magnetic multilayers (invited)
Authors: Tserkovnyak Yaroslav , Brataas Arne , Bauer Gerrit E. W.
Published: May 2003

We theoretically study dynamic properties of thin ferromagnetic films in contact with normal metals. Moving magnetizations cause a flow of spins into adjacent conductors, which relax by spin flip, scatter back into the ferromagnet, or are absorbed by another ferromagnet. Relaxation of spins outside the moving magnetization enhances the overall damping of the magnetization dynamics in accordance with the Gilbert phenomenology. Transfer of spins between different ferromagnets by these nonequilibrium spin currents leads to a long-ranged dynamic exchange interaction and collective excitation modes. Our predictions agree well with recent ferromagnetic-resonance experiments on ultrathin magnetic films.
Ordering process of sputtered FePt films
Authors: Takahashi Y. K. , Ohnuma M. , Hono K.
Published: May 2003

We have investigated the in situ ordering process of sputtered FePt thin films deposited on heated substrates at 300 °C with different thicknesses. The films thinner than 50 nm were composed of nanograins (∼5 nm) of disordered FePt phase. Recrystallization occured when films were grown thicker than 100 nm, and transformation twins were observed in recrystallized grains, in which ordering to the L10 structure was confirmed.
Anisotropy and Ising-type transition of the S=5/2 two-dimensional Heisenberg antiferromagnet Mn-formate di-Urea
Authors: Cuccoli Alessandro , Roscilde Tommaso , Tognetti Valerio , Vaia Ruggero , Verrucchi Paola
Published: May 2003

Recently reported measurements of specific heat on the compound Mn-formate di-Urea by Takeda et al. [Phys. Rev. B 63, 024425 (2001)] are considered. As a model to describe the overall thermodynamic behavior of such a compound, the easy-axis two-dimensional Heisenberg antiferromagnet is proposed and studied by means of the pure quantum self-consistent harmonic approximation. In particular, it is shown that when the temperature decreases, the compound exhibits a crossover from two-dimensional (2D) Heisenberg to 2D-Ising behavior, followed by a 2D-Ising-type phase transition, whose location allows one to get a reliable estimate of the easy-axis anisotropy driving the transition itself. Below the critical temperature TN=3.77 K, the specific heat is well described by the two-dimensional easy-axis model down to a temperature T*=1.57 K, where a T3 law sets in, possibly marking a low-temperature crossover of magnetic fluctuations from two to three dimensions.
Numerical studies of the two- and three-dimensional gauge glass at low temperature
Authors: Katzgraber Helmut G.
Published: May 2003

We report results from Monte Carlo simulations of the two- and three-dimensional gauge glass at low temperature using parallel tempering Monte Carlo. In two dimensions, we find strong evidence for a zero-temperature transition. By means of finite-size scaling, we determine the stiffness exponent θ=−0.39±0.03. In three dimensions, where a finite-temperature transition is well established, we find θ=0.27±0.01, compatible with recent results from domain-wall renormalization group studies.
High hysteresis in a homogeneous metallic glass
Authors: Branagan D. J. , Meacham B. E. , McCallum R. W. , Dennis K. W. , Kramer M. J.
Published: May 2003

In this article, we demonstrate high hysteresis in a well characterized homogeneous Tb–Al glass which contained no crystallites or crystalline embryos as verified using conventional and synchrotron diffraction, neutron diffraction, and direct observation in the transmission electron microscope. At low temperature (2 K), the metallic glass structure exhibited intrinsic coercivities approaching 23 kOe and high isotropic energy products of 12.4 MGOe. After crystallization into a three-phase nanoscale structure, the hard magnetic properties were found to be far inferior to that obtainable in the glass structure. From the well defined intrinsic magnetic properties (Msat,Tc), it is clear that the glass contains one or more types of well defined associations (i.e., clusters) and that these associations lead to ferromagnetic coupling/ordering. From the large random magnetic anisotropy, it is probable that the domain size is much larger than the structural cluster size. The measured single-phase loop shapes and the development of high coercivity in the glass state can be explained by an “exchange bias” mechanism resulting in a near perfect distribution of “fragile” pinning centers.
Crystallization behavior and magnetic properties of the low rare-earth content (Nd=6 at. %) Nd–Fe–Co–V–B nanocomposite magnet ribbons prepared by rapid quenching method
Authors: Ono H. , Tayu T. , Waki N. , Sugiyama T. , Shimada M. , Kanou M. , Yamamoto H. , Takasugi K.
Published: May 2003

The low rare-earth content α-Fe/Nd2Fe14B nanocomposite magnets having a high soft phase ratio were fabricated by the rapid quenching method and evaluations were made of the crystallization behavior, microstructure, and magnetic properties in the annealing process. An investigation of the relationship between the roller surface velocity, Vs, and magnetic properties showed that changes in the crystal grain size of the α-Fe phase following annealing could be attributed to differences in the amorphous content of the as-melt-spun ribbons. As the amorphous content was increased, their crystal grain size tended to become finer and their magnetic properties tended to improve. However, it was observed that the optimum rapid quenching rate exists. The slight presence of clusters in as-melt-spun ribbons is favorable for obtaining good magnetic properties because the growth of α-Fe crystals is inhibited. The presumed reason for this inhibiting effect is that α-Fe growth occurs in a process in which clusters containing Nd expel this element. In the case of a completely amorphous state, large crystals grew easily, because they consisted of only Fe and Co in the initial stage.
RC-coupled ferromagnetic single-electron transistors
Authors: Shirakashi Jun-ichi , Takemura Yasushi
Published: May 2003

We study quantitatively the operation of ferromagnetic single-electron transistors coupled to the controlling gate potential by the gate resistance and gate capacitance in series. In this type of the device, several metastable charge states are possible within the range of Coulomb blockade. The enhancement and hysteresis of tunnel magnetoresistance on the drain and gate voltages are predicted. The inelastic macroscopic quantum tunneling of charge and the existence of several charge states play an important role in the unique behavior of tunnel magnetoresistance. This implies that RC-coupled ferromagnetic single-electron transistors have a functionality as novel magnetoresistive nanostructure devices.
Magnetization reversal and domain structure of antiferromagnetically coupled submicron elements
Authors: Tezuka N. , Koike N. , Inomata K. , Sugimoto S.
Published: May 2003

Switching characteristics and magnetic domain structures in submicron size synthetic antiferromagnets (SyAF), Co90Fe10/Ru/Co90Fe10 have been studied. Submicron size elements with well defined geometry were prepared by electron beam lithography and argon ion milling for SyAFs and Co90Fe10 monolayers deposited by an ultrahigh vacuum sputtering system. Hysteresis loops were obtained by a focused magneto-optic Kerr effect (MOKE) system and magnetic images in the remanent state were observed by magnetic force microscopy (MFM). We found that the MFM images of SyAF exhibit a single domain structure even in the case of aspect ratio of 1, and there is an optimum ferromagnetic film thickness at which SyAF can obtain a single domain structure with such a low aspect ratio. The MOKE results show that the switching field is dependent on the element width and aspect ratio.
Magnetic properties of hydrogen-induced amorphous YFe2
Authors: Suzuki K. , Ishikawa K. , Dilixiati M. , Cadogan J. M. , Aoki K.
Published: May 2003

In order to clarify the origin of the absence of a spin glass state from hydrogen-induced amorphous (HIA) YFe2(H) alloys, the magnetic properties of HIA YFe2Hx (x=0.9, 1.9, and 3.6) alloys were investigated by Fe57 Mössbauer spectroscopy, ac susceptometry, and thermogravimetric magnetic analysis. Both the mean hyperfine field (〈Bhf〉) at 0 K and the magnetic transition temperature in the HIA YFe2Hx alloys show a tendency to decrease with a decrease in x. The exchange integral (J) estimated from the temperature dependence of 〈Bhf〉 is also reduced dramatically with a decrease in x. The absence of a spin glass state in HIA YFe2(H) is understood well by the enhancement of J through the volume expansion induced by the absorption of hydrogen.