bluuebunny/crossref_metadata_2025 huggingface dataset:
Platelet glycoprotein Ia 807C/T (Phe224) and 873G/A (Thr246) dimorphisms in Turkey
Authors: Komurcu Evrim , Erginel‐Unaltuna Nihan
Published: August 2002

At sites of vascular injury, the platelet collagen receptor Glycoprotein Ia/IIa (GPIa/IIa) acts as an important mediator of platelet adhesion to fibrillar collagens. Two silent polymorphisms (807C/T and 873G/A) within the glycoprotein Ia gene have been implicated in increased risk of developing thrombosis and myocardial infarction in affected individuals. To provide basis for future studies, we examined the frequency of these GPIa polymorphisms for people in Turkey. We analyzed 118 unrelated individuals for their genotypes of the GPIa gene using a multiplexed allele specific‐PCR based method. The allelic frequencies were found to be 34% for 807T/873A and 66% for 807C/873G; the genotypic frequencies were 13% for 807TT/873AA, 44% for 807CT/873GA, and 43% for 807CC/873GG. Am. J. Hematol. 69:83‐84, 2002. © 2002 Wiley‐Liss, Inc.
Expression of tissue factor and vascular endothelial growth factor is associated with angiogenesis in colorectal cancer
Authors: Nakasaki Takahiro , Wada Hideo , Shigemori Chika , Miki Chikao , Gabazza Esteban C. , Nobori Tsutomu , Nakamura Shin , Shiku Hiroshi
Published: August 2002

We examined the expression of tissue factor (TF) and vascular endothelial growth factor (VEGF) and the microvessel density (MVD) in 100 patients with colorectal cancer, and we investigated the relationship of the expression of TF or VEGF with angiogenesis. TF antigen was positive in 57.0% of all specimens. Incidence of TF expression was 41.2%, 45.5%, 52.6%, 84.6%, and 81.3% in tumors from patients in clinical stages I, II, IIIA, IIIB, and IV, respectively. TF expression was correlated with the Dukes' classification (P = 0.01) and the clinical stage of colorectal cancer (P = 0.02). VEGF antigen was positive in 64.0% of all specimens. Incidence of VEGF expression was 41.2%, 57.6%, 73.7%, 84.6%, and 75.0% in tumors from patients in clinical stages I, II, IIIA, IIIB, and IV, respectively. VEGF expression was correlated with the Dukes' classification (P = 0.01) but showed a weak association with the clinical stage (P = 0.08). MVD was significantly associated with the depth of invasion (P = 0.01), lymph node metastasis (P = 0.001), and liver metastasis (P = 0.02). The mean values of MVD were 7.5 ± 2.8, 10.1 ± 5.7, 14.6 ± 5.8, 13.5 ± 3.9, and 15.9 ± 4.2 in tumors from patients in clinical stages I, II, IIIA, IIIB, and IV, respectively. A close relationship between VEGF and MVD (P < 0.001) and a significant correlation between TF expression and MVD were observed (P = 0.02). TF‐positive carcinomas presented high MVD and VEGF expression (P < 0.001) more frequently than did TF‐negative tumors. These results suggest that involvement of TF in the process of metastasis and progression of colorectal cancer may depend on increased angiogenesis. Am. J. Hematol. 69:247–254, 2002. © 2002 Wiley‐Liss, Inc.
Diverse clinical outcomes of eosinophilic patients with T‐cell receptor gene rearrangements: The emerging diagnostic importance of molecular genetics testing
Authors: Butterfield Joseph H.
Published: August 2002

Abnormal clones of clusters of differentiation (CD)3−CD4+ or CD3+CD4−CD8− phenotypically abnormal lymphocytes have been identified in some patients who have the idiopathic hypereosinophilic syndrome. This report illustrates the disparate clinical courses of six eosinophilic patients with evidence of abnormal T‐cell clones based on the finding of a T‐cell receptor gene rearrangement. The data suggest that molecular genetics testing for T‐cell receptor gene rearrangements should be included in the routine work‐up of patients with idiopathic eosinophilia. Am. J. Hematol. 68:81–86, 2001. © 2001 Wiley‐Liss, Inc.
Ethical issues in the management of sickle cell pain
Authors: Ballas Samir K.
Published: August 2002

Care providers who manage patients with sickle cell disease (SCD) often face several questions. Most prominent among these pertain to the importance of pain and its treatment. The duties of the health care providers concerning pain management are often not well defined and vary considerably among providers and institutions. Despite the availability of national guidelines that address the ethical issues of pain management, patients with SCD often receive suboptimal pain control, especially during acute painful episodes. Although there are many reasons for this situation, an important aspect of the problem pertains to the complexity of applying ethical standards to specific patients with sickle cell pain. Decisions are frequently made according to perceptions and circumstances without taking ethical principles into consideration. The purpose of this paper is to present the range of ethical principles pertinent to sickle pain management and discuss specific examples of physician‐patient interactions where ethical dilemmas occur. Am. J. Hematol. 68:127–132, 2001. © 2001 Wiley‐Liss, Inc.
Early identification and intervention in the prevention of musculoskeletal pain
Authors: Linton Steven James
Published: August 2002

Background

A large number of people suffer from upper extremity disorders, but a few apparently consume the majority of the resources. Early interventions are badly needed to prevent the development of persistent disability. Since psychological factors are central in the development of a chronic problem these might be utilized in this endeavor.

Methods

A series of studies are described where a screening procedure based on psychological risk factors was employed to help identify people at risk for developing long‐term work disability. The utility of a cognitive‐behavioral group intervention that focuses on coping strategies as prevention was assessed in three randomized‐controlled studies where participants had low, medium, and high risk, respectively.

Results

The study with low risk showed no significant difference between the groups, while the studies with medium‐ and high‐risk populations demonstrated significantly lower work disability than control groups receiving treatment as usual.

Conclusions

It appears to be feasible to identify patients with high levels of risk and to subsequently lower the risk for work disability by administering a cognitive‐behavioral intervention focusing on psychological aspects of the pain problem. Am. J. Ind. Med. 41:433–442, 2002. © 2002 Wiley‐Liss, Inc.
Biobehavioral mechanisms of work‐related upper extremity disorders: A new agenda for research and practice
Authors: Feuerstein Michael
Published: August 2002

Background

Epidemiological studies provide support for the role of organizational and individual psychosocial stressors in work‐related upper extremity disorders (WRUEDs). Despite this evidence, the biological plausibility of a relationship between exposure to various psychosocial and work organizational stressors and WRUEDs remains unclear.

Methods

The Georgetown Symposium on Biobehavioral Mechanisms of Work‐Related Upper Extremity Disorders was held in Washington D.C. on November 6–7, 2000 to improve the understanding of potential biobehavioral mechanisms, identify future areas for research and discuss the implications of this body of knowledge for intervention. This meeting involved presentations and discussions by researchers and clinicians from a number of disciplines (epidemiology, occupational medicine, rheumatology, orthopedics, surgery, internal medicine, psychoneuroimmunology, occupational health psychology, behavioral medicine, psychophysiology and experimental and organizational psychology).

Results

The symposium generated several papers addressing the following topics: definitions and job stress models; epidemiological foundations; musculoskeletal and biomechanical models; central nervous system models of recurrent and persistent clinical pain; psychophysiology of work; and implications for intervention. These papers comprise this special issue.

Discussion

The present paper summarizes the various contributions to this special issue and provides direction for future research on potential biobehavioral pathways. Am. J. Ind. Med. 41:293–297, 2002. © 2002 Wiley‐Liss, Inc.
Multilevel nerve compression and muscle imbalance in work‐related neuromuscular disorders*
Authors: Novak Christine B. , Mackinnon Susan E.
Published: August 2002

Background

Work‐related upper limb disorders have come under increasing scrutiny and become a frustrating problem.

Methods

A unifying hypothesis to explain the multiplicity of symptoms with work related neuromuscular disorders is outlined. This multifactorial problem includes physical, individual, and psychosocial factors. Abnormal postures and positions may compress nerves or may alter muscle length resulting in secondary compressive forces on nerves or in muscle imbalances. Evaluation should identify all nerve compression levels and muscle imbalance in the arm and cervicoscapular region. Management must include patient education, postural correction, and an exercise program to address the multiple nerve compression levels and muscle imbalance.

Results and Conclusions

The etiology of work related neuromusculoskeletal disorders is multifactorial and successful management must address all contributing factors. Appropriate conservative management will relieve symptoms in most patients. Surgery should be reserved for those few patients with evidence of a specific diagnosis who have failed conservative management. Am. J. Ind. Med. 41:343–352, 2002. © 2002 Wiley‐Liss, Inc.
Genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) in ethnic populations in Texas; a report of a novelMTHFRpolymorphic site, G1793A
Authors: Rady Peter L. , Szucs Sylvia , Grady James , Hudnall S. David , Kellner Leonard H. , Nitowsky Harold , Tyring Stephen K. , Matalon Reuben K.
Published: August 2002

The importance of hyperhomocysteinemia, birth defects, and vascular diseases has been the subject of intense investigations. The polymorphicMTHFRmutations (C677T and A1298C) cause mild hyperhomocysteinemia, especially in homozygotes for C677T, but also in compound heterozygotes for C677T/A1298C. The subject of this report is the frequency of the polymorphic mutations in theMTHFRgene C677T, C1298A, and newly discovered mutation G1793A, as well as the association withMTRRpolymorphic site A66G in different ethnic groups. Four ethnic groups were studied: African‐Americans, Caucasians, Hispanics, and Ashkenazi Jews. There are statistically significant differences in the frequency of these alleles in the different populations studied, which impacts compound heterozygosity for such alleles in these populations. DNA samples obtained from the blood of healthy individuals of African‐Americans, Hispanics, and Caucasians from south Texas were analyzed and compared to those obtained from Ashkenazi Jewish individuals. The polymorphic site, the G1793A allele, is least frequent among Ashkenazi individuals, 1.3%, compared to 6.9% among Caucasians (P = 0.001), 5.8% among Hispanics (P = 0.012), and 3.1% among African‐Americans. TheMTRRpolymorphic site shows the lowest allele frequency among Hispanics, 28.6%, compared to 34% among African‐Americans, 43.1% among Ashkenazi Jews (P = 0.002), and 54.4% among Caucasians (P < 0.0001). Statistically significant differences in allele frequencies of C677T and C1298A polymorphisms were also observed in these populations. Compound heterozygosity for multiple polymorphic alleles may play a role in birth defects and vascular diseases. © 2001 Wiley‐Liss, Inc.
Family‐based association study of 5‐HTTLPR, TPH, MAO‐A, and DRD4 polymorphisms in mood disorders
Authors: Serretti Alessandro , Cristina Silvano , Lilli Roberta , Cusin Cristina , Lattuada Enrico , Lorenzi Cristina , Corradi Barbara , Grieco Gaetano , Costa Alfredo , Santorelli Filippo , Barale Francesco , Nappi Giuseppe , Smeraldi Enrico
Published: August 2002

Variants of the functional polymorphism in the serotonin transporter (upstream regulatory region: 5‐HTTLPR), the tryptophan hydroxylase (TPH), the monoamine oxidase A (MAO‐A), and the dopamine receptor D4 (DRD4) genes have all been associated with mood disorders. The aim of this study was to test those hypotheses by using a family‐based association approach. Both diagnoses and psychopathology were used for phenotype definitions. A total of 134 nuclear families with mood disorders, with probands affected by bipolar (n = 103) or major depressive (n = 58) disorders, were included in the study. All subjects were typed for the above‐mentioned gene variants using polymerase chain reaction (PCR) technique. No significant transmission disequilibrium was found in the overall sample for any polymorphism. A separate analysis of bipolar subjects only, or the use of continuous psychopathologic traits as affectation status did not influence the observed results. Our study did not support the involvement of 5‐HTTLPR, TPH, MAO‐A, or DRD4 polymorphisms in mood disorders. © 2002 Wiley‐Liss, Inc.
Terminal deletion of the chromosome 7(q36–qter) in an infant with sacral agenesis and anterior myelomeningocele
Authors: Rodríguez Laura , Cuadrado Pérez Irene , Herrera Montes Juana , Lorente Jareño Maria Luisa , López Grondona Fermina , Martínez‐Frías Maria Luisa
Published: August 2002

We report on a new patient with a 7q terminal deletion. The 18‐month‐old boy had metal retardation, microcephaly, a distinctive face, bilateral coloboma, café‐au‐lait spot on the abdomen, and sacral agenesis. The high resolution GTG bands (550–850 bands), currently used in our laboratory, showed a 7q terminal deletion, which was also confirmed with fluorescence in situ hybridization (FISH). The homeobox HLXB9 gene, localized at 7q36 has been demonstrated to be involved in sacral agenesis; in fact patients with 7q terminal deletions frequently have this malformation. We could not perform molecular studies in this patient to confirm the HLXB9 haploinsufficiency, but we postulate that he carried it. © 2002 Wiley‐Liss, Inc.
Genome survey for susceptibility loci for recurrent, early‐onset major depression: Results at 10cM resolution
Authors: Zubenko George S. , Hughes Hugh B. , Stiffler J. Scott , Zubenko Wendy N. , Kaplan Barry B.
Published: August 2002

Recurrent (two or more episodes), early‐onset (first episode at ≤ 25 years) major depressive disorder (RE‐MDD) is a strongly familial condition (λfirst‐degreerelatives = 8) whose malignant effects have a significant negative impact on the health and longevity of patients and their family members. The goal of this study was to identify candidate susceptibility loci that influence the development of RE‐MDD. We completed a systematic survey of the human genome, conducted at an average resolution of 10 cM, for the identification of simple sequence tandem repeat polymorphisms (SSTRPs) that target susceptibility genes for RE‐MDD by virtue of linkage disequilibrium. The efficiency of our association study was enhanced by genotyping pools of DNA from 100 adults with RE‐MDD and 100 adult controls who had no personal or family history of mental disorders. Both groups included equal numbers of Caucasian men and women and were matched as closely as possible for age and ethnicity. Allelic associations with RE‐MDD were observed for 19 of the 387 SSTRPs in the CHLC Human Screening Set/Weber Version 9. Sixteen of the 19 candidate susceptibility loci revealed significant allelic associations with RE‐MDD in men (n = 7) or women (n = 9), but not in both sexes. Evidence for both risk and protective alleles was detected. Two of the candidate susceptibility loci reside within several Mb of loci previously reported‐megabases to be linked to “comorbid alcoholism and depression” in families of individuals with alcoholism and to a broadly defined affected phenotype that included recurrent major depression in the families of patients with bipolar disorder. Although it has been suggested that the genes that influence risk for MDD in the two sexes may not be entirely the same, the results of our study suggest that sex specificity of susceptibility loci for RE‐MDD may be the rule rather than the exception. The observed preponderance of sex‐specific susceptibility loci for RE‐MDD suggests that there may be important differences in the molecular pathophysiology of RE‐MDD in men and women. Alternatively, our findings may reflect the existence of sex‐specific differences in the molecular mechanisms that determine resilience to endogenous or environmental depressogenic stimuli. © 2002 Wiley‐Liss, Inc.
Linkage study of polymorphisms in the gene for myelin oligodendrocyte glycoprotein located on chromosome 6p and attention deficit hyperactivity disorder
Authors: Barr Cathy L. , Shulman Rayzie , Wigg Karen , Schachar Russell , Tannock Rosemary , Roberts Wendy , Malone Molly , Kennedy James L.
Published: August 2002

Family and twin studies have shown that there is a substantial genetic contribution to both reading disabilities (RD) and attention deficit hyperactivity disorder (ADHD), and recent twin studies have suggested that the overlap between these phenotypes is largely due to common genetic influences. Studies using a linkage approach to search for genes for susceptibility to RD and ADHD have identified regions linked to each of these phenotypes separately, with recent studies suggesting that some chromosomal regions may contribute to both. Linkage to the human leukocyte antigen (HLA) region has been targeted in particular for RD and ADHD, as both of these disorders have been suggested to be autoimmune. Linkage to the HLA region of 6p for RD has now been reported by several groups. Alleles at two genes in the HLA (C4B and DRB1) have also been reported to be associated with ADHD, prompting one investigator to suggest a possible connection between the linkage of RD and ADHD to this region. The location of the gene for myelin oligodendrocyte glycoprotein (MOG), in the region of 6p with the strongest evidence for linkage to RD, and its proposed role as a minor component of myelin in the central nervous system suggest that it may be a factor in neuronal functioning and therefore a candidate for RD and ADHD. In this study, we tested the gene for linkage to ADHD by genotyping two polymorphisms in the MOG gene—a dinucleotide repeat located upstream from the MOG transcription start site and a Val145Ile substitution in exon 3—in a sample of 104 nuclear families identified through a proband with ADHD. We examined the transmission of the alleles of the Val145Ile and the dinucleotide repeat polymorphisms using the transmission disequilibrium test. We did not observe biased transmission of the alleles at either polymorphism to ADHD probands or siblings. Our findings using this sample do not support the role of the MOG gene in ADHD. © 2001 Wiley‐Liss, Inc.
Lack of association between a functional polymorphism of the cytochrome P450 1A2 (CYP1A2) gene and tardive dyskinesia in schizophrenia
Authors: Schulze Thomas G. , Schumacher Johannes , Müller Daniel J. , Krauss Harald , Alfter Daniela , Maroldt Alexandra , Ahle Guido , Maroldt Ansgar‐Otto , Novo y Fernández Ana , Weber Thomas , Held Tilo , Propping Peter , Maier Wolfgang , Nöthen Markus M. , Rietschel Marcella
Published: August 2002

Tardive dyskinesia (TD) is a common side effect of long‐term medication with typical neuroleptics. TD presents itself by abnormal involuntary movements and may lead to a potentially disabling and chronic clinical course. A vast majority of patients suffering from schizophrenia are smokers. Smoking has been reported to induce the activity of the CYP1A2 enzyme, which is an established metabolic pathway within the disposition of antipsychotics. Recently, a C→A genetic polymorphism in the first intron of the CYP1A2 gene was reported to influence CYP1A2 activity in smokers. Subsequently, a pharmacogenetic study in 85 U.S. patients with schizophrenia (44 smokers, 41 individuals with unknown smoking status) showed the C/C genotype to be associated with higher TD severity (measured by the Abnormal Involuntary Movement Scale, AIMS) than the A/C or A/A genotype. This finding prompted us to investigate whether this effect was also present in a larger German sample of 119 patients with schizophrenia (82 smokers, 37 individuals with unknown smoking status). However, we could not replicate the reported association. The median AIMS scores did not differ between individuals with the A/A, A/C, or C/C genotypes. In an additional analysis, we compared the genotypic and allelic distribution among individuals grouped according to the criteria established by Schooler and Kane [1982: Arch Gen Psychiatry 39:486–487] (persistent TD vs. absent TD). We did not observe a differential genotypic or allelic distribution between the two diagnostic groups. Thus, our results do not support the hypothesis that the C→A polymorphism in the CYP1A2 gene is involved in the etiology of TD in the German population. © 2001 Wiley‐Liss, Inc.
Modulation of use‐dependent plasticity by d‐amphetamine
Authors: Bütefisch Cathrin M. , Davis Benjamin C. , Sawaki Lumy , Waldvogel Daniel , Classen Joseph , Kopylev Leonid , Cohen Leonardo G.
Published: August 2002

Use‐dependent plasticity, thought to contribute to functional recovery after brain injury, is elicited by motor training. The purpose of this study was to determine if administration of d‐amphetamine facilitates the effects of motor training on use‐dependent plasticity. Healthy human volunteers underwent a training period of voluntary thumb movements under the effects of placebo or d‐amphetamine in different sessions in a randomized double‐blind, counterbalanced design. Previous work in a drug‐naive condition showed that such training causes changes in the direction of thumb movements evoked by transcranial magnetic stimulation and in transcranial magnetic stimulation‐evoked electromyographic responses. The endpoint measure of the study was the magnitude of training‐induced changes in transcranial magnetic stimulation‐evoked kinematic and electromyographic responses in the d‐amphetamine and in the placebo conditions. Motor training resulted in increased magnitude, faster development and longer lasting duration of use‐dependent plasticity under d‐amphetamine compared to the placebo session. These results document a facilitatory effect of d‐amphetamine on use‐dependent plasticity, a possible mechanism mediating the beneficial effect of this drug on functional recovery after cortical lesions.
Superior oblique myokymia: Magnetic resonance imaging support for the neurovascular compression hypothesis
Authors: Yousry Indra , Dieterich Marianne , Naidich Thomas P. , Schmid Urs D. , Yousry Tarek A.
Published: August 2002

Superior oblique myokymia is a rare movement disorder thought to be caused by vascular compression of the trochlear nerve. Direct display of such neurovascular compression by magnetic resonance imaging has been lacking. The goal of this study was to assess the presence of neurovascular contacts in patients with superior oblique myokymia, using a specific magnetic resonance imaging protocol. A total of 6 patients suffering from right superior oblique myokymia underwent detailed neuro‐ophthalmological examination, which showed tonic or phasic eye movement. All patients underwent magnetic resonance imaging, using a magnetic resonance imaging Fourier transform constructive interference in steady‐state sequence in combination with magnetic resonance imaging time of flight magnetic resonance arteriography both before and after the administration of Gd‐DTPA. With this protocol, the trochlear nerve could be visualized on 11 of 12 sides (92%). Arterial contact was detected at the root exit zone of the symptomatic right trochlear nerve in all 6 patients (100%). No arterial contact was identified at the root exit zone of the asymptomatic left trochlear nerve in any of the 5 left nerves visualized. In conclusion, superior oblique myokymia can result from neurovascular contact at the root exit zone of trochlear nerve, and therefore should be considered among the neurovascular compression syndromes.
Comparison of weakness progression in inclusion body myositis during treatment with methotrexate or placebo
Authors: Badrising Umesh A. , Maat‐Schieman Marion L.C. , Ferrari Michel D. , Zwinderman Aeilko H. , Wessels Judith A.M. , Breedveld Ferdinand C. , van Doorn Pieter A. , van Engelen Baziel G.M. , Hoogendijk Jessica E. , Höweler Chris J. , de Jager Aeiko E. , Jennekens Frans G.I. , Koehler Peter J. , de Visser Marianne , Viddeleer Alain , Verschuuren Jan J. , Wintzen Axel R.
Published: August 2002

We investigated whether 5 to 20mg per week oral methotrexate could slow down disease progression in 44 patients with inclusion body myositis in a randomized double‐blind placebo‐controlled study over 48 weeks. Mean change of quantitative muscle strength testing sum scores was the primary study outcome measure. Quantitative muscle strength testing sum scores declined in both treatment groups, −0.2% for methotrexate and −3.4% for placebo (95% confidence interval = −2.5% to +9.1% for difference). There were also no differences in manual muscle testing sum scores, activity scale scores and patients' own assessments after 48 weeks of treatment. Serum creatine kinase activity decreased significantly in the methotrexate group. We conclude that oral methotrexate did not slow down progression of muscle weakness but decreased serum creatine kinase activity.
Functional recovery and neuroanatomical plasticity following middle cerebral artery occlusion and IN‐1 antibody treatment in the adult rat
Authors: Papadopoulos Catherine M. , Tsai Shih‐Yen , Alsbiei Talal , O'Brien Timothy E. , Schwab Martin E. , Kartje Gwendolyn L.
Published: August 2002

Stroke is a prevalent and devastating disorder, and no treatment is currently available to restore lost neuronal function after stroke occurs. One unique therapy that may improve functional recovery after stroke is blockade of the neurite inhibitory protein Nogo‐A with the monoclonal antibody IN‐1, through enhancement of neuroanatomical plasticity from uninjured areas of the central nervous system. In the present study, we combined IN‐1 treatment with an ischemic lesion (permanent middle cerebral artery occlusion) to determine the effect of Nogo‐A neutralization on cortical plasticity and functional recovery. We report here that, following ischemic stroke and treatment with IN‐1, adult rats demonstrated functional recovery on a forelimb‐reaching task and new cortico‐efferent projections from the opposite, unlesioned hemisphere. These results support the efficacy of Nogo‐A blockade as a treatment for ischemic stroke and implicate plasticity from the unlesioned hemisphere as a mechanism for recovery.
Platelet‐activating factor acetylhydrolase activity in cerebrospinal fluid of children with acute systemic or neurological illness
Authors: Chang Hyeun‐Wook , Kwon Soonhak , Kim Hengmi , Lee Kunsoo , Kim Misuk , Moon Taechul , Baek Sukhwan
Published: August 2002

Platelet‐activating factor acetylhydrolase was analyzed in cerebrospinal fluid samples taken from children with a variety of neurological conditions (85 patients; mean age, 3.8 years) to determine it is involved in the defense mechanism against the toxic effect of inflammatory mediators in the central nervous system. A significant increase in cerebrospinal fluid activity was seen in the patients with meningitis and acute febrile illness in comparison with the control subjects. The activity was also significantly higher in the patients with meningitis than in the patients with inflammatory neurological diseases. In addition, the biochemical profile of cerebrospinal fluid platelet‐activating factor acetylhydrolase was different from other known acetylhydrolases. These findings suggest that cerebrospinal fluid platelet‐activating factor acetylhydrolase activity may be a sensitive marker of the host response to central nervous system infections.
Subclinical dopaminergic dysfunction in asymptomatic Parkinson's disease patients' relatives with a decreased sense of smell
Authors: Berendse Henk W. , Booij Jan , Francot Chantal M. J. E. , Bergmans Paul L. M. , Hijman Ron , Stoof Johannes C. , Wolters Erik Ch.
Published: August 2002

By the time a clinical diagnosis of Parkinson's disease (PD) is made, a significant loss of dopaminergic neurons has already occurred. Identifying patients in the period between the presumed onset of dopaminergic cell loss and the appearance of clinical parkinsonism may be of major importance in the development of effective neuroprotective treatment strategies. In an effort to develop a feasible strategy to detect preclinical PD, a combination of olfactory processing tasks, including odor detection, odor identification, and odor discrimination was used to select groups of hyposmic and normosmic individuals from a total of 250 relatives (parents, siblings, or children) of subjects with PD. Single photon emission computed tomography (SPECT) with [123I]β‐CIT as a dopamine transporter ligand was used to assess nigrostriatal dopaminergic function in 25 hyposmic and 23 normosmic relatives of PD patients. An abnormal reduction in striatal dopamine transporter binding was found in 4 out of 25 hyposmic relatives of PD patients, 2 of whom subsequently developed clinical parkinsonism, and in none of the 23 normosmic relatives. These observations demonstrate that subclinical reductions in dopamine transporter binding can be detected in asymptomatic relatives of sporadic PD patients by means of [123I]β‐CIT and SPECT. The results further indicate that olfactory deficits may precede clinical motor signs in PD.
Dehydrocoupling of tris(hydridosilylethyl)boranes with ammonia or amines: a novel route to Si–B–C–N preceramic polymers
Authors: Weinmann Markus , Nast Sabine , Berger Frank , Kaiser Gerhard , Müller Klaus , Aldinger Fritz
Published: August 2002

The synthesis of boron‐modified polysilazanes­of general type {B[C2H4Si(R)NR′]3}
n [R = CH3, (NR′)0.5; R′ = H, CH3] by dehydrogenative coupling of tris(hydridosilylethyl)boranes B[C2H4Si(CH3)
nH3−n]3 (C2H4 = CHCH3, CH2CH2; n = 0, 1) and ammonia or methylamine is reported. Detailed characterization of the title compounds was performed using spectroscopic methods such as solid‐state NMR spectroscopy, IR spectroscopy, and elemental analysis. Thermolysis produces amorphous Si–B–C–N ceramics with ceramic yields between 25 and 83%, as determined by thermogravimetric analysis (TGA) in argon. High‐temperature TGA in an argon atmosphere reveals that a number of the ceramics obtained resist degradation up to ∼2000 °C. X‐ray diffraction studies of the as‐obtained amorphous materials show formation of α‐SiC or α‐SiC/β‐Si3N4 crystalline phases between 1600 and 1800 °C, depending on the composition of the materials. Copyright © 2001 John Wiley & Sons, Ltd.
Precursor‐derived Si–(B–)C–N ceramics: thermolysis, amorphous state and crystallization
Authors: Bill Joachim , Kamphowe Thomas W. , Müller Anita , Wichmann Thomas , Zern Achim , Jalowieki Artur , Mayer Joachim , Weinmann Markus , Schuhmacher Jörg , Müller Klaus , Peng Jianqiang , Seifert Hans Jürgen , Aldinger Fritz
Published: August 2002

The preparation of silicon nitride‐ and carbide‐based ceramics by solid‐state thermolysis of polysilazanes and polysilylcarbodiimides is described. Results on the ceramization of the preceramic compounds and the architecture of the corresponding amorphous states obtained by spectroscopic means and by X‐ray and neutron scattering are reviewed. Fundamental correlations between the composition and structure of the preceramic compounds and the architecture of the amorphous state are revealed. Furthermore, the crystallization behavior of the amorphous precursor‐derived Si–C–N ceramics is treated. Moreover, the influence of boron on the thermal stability of the amorphous state is described. The high‐temperature behavior of these Si–B–C–N solids can be correlated with their phase composition. Ceramic materials with compositions located close to the three‐phase equilibrium SiC + BN + C exhibit a high temperature stability up to 2000 °C. This effect is accompanied by the formation of a metastable solid consisting of Si3N4and SiC nanocrystals that are embedded in a turbostratic B–C–N matrix phase. Based on thermodynamic considerations, a model for the high‐temperature stability effect is proposed. Copyright © 2001 John Wiley & Sons, Ltd.
Pretreatment procedure for selenium speciation in shellfish using high‐performance liquid chromatography–microwave‐assisted digestion–hydride generation‐atomic fluorescence spectrometry
Authors: Gómez‐Ariza J. L. , Caro de la Torre M. A. , Giráldez I. , Sánchez‐Rodas D. , Velasco A. , Morales E.
Published: August 2002

A pretreatment procedure based on an enzymatic hydrolysis extraction followed by a two‐step clean‐up has been performed for selenium speciation in shellfish samples. Bivalve samples were extracted with protease XIV, lipase VII and protease VIII. By using a protease VIII–lipase VII mixture, quantitative recoveries were obtained for all the selenium species, except for selenocystine (59%). Owing to the complexity of the matrix, clean‐up procedures were required to remove interferents that affected the chromatographic separation. The extracts were first partitioned in dichloromethane and then passed through a column with aminopropylsilane. Speciation of selenocystine, selenomethionine, selenoethionine, selenite and selenate was obtained using a high‐performance liquid chromatography–microwave‐assisted digestion–hydride generation‐atomic fluorescence spectrometry coupling. The chromatographic system consisted of an anion exchange and a reversed‐phase column, both connected through a six‐port switching valve. On‐line microwave‐assisted digestion and hydride generation steps were performed prior to atomic fluorescence detection. The method was applied to clam and prawn samples collected from the southwest coast of Spain. Copyright­© 2002 John Wiley & Sons, Ltd.
Reinforcement of EPDM by in situ prepared zinc dimethacrylate
Authors: Peng Zonglin , Liang Xun , Zhang Yinxi , Zhang Yong
Published: August 2002

The mechanical properties and crosslink density of peroxide‐cured ethylene‐propylene‐diene rubber (EPDM) reinforced with zinc dimethacrylate (ZDMA) were studied. ZDMA was in situ prepared in EPDM matrix through the neutralization reaction of zinc oxide (ZnO) and methacrylate acid (MAA). The effect of ZnO/MAA amount and molar ratio of ZnO/MAA on the properties of the EPDM vulcanizate were investigated in detail. The experimental results showed that EPDM can be greatly reinforced by ZDMA. The excess amount of ZnO considerably increases the tensile strength of the EPDM vulcanizate to reach as high as 37 MPa, whereas its elongation at break keeps over 350%. The process of in situ formation of ZDMA in the EPDM compound was verified by WAXD. Such vulcanizate contains both covalent crosslinks and ionic crosslinks. Crosslink density was determined by an equilibrium swelling method. Dependence of crosslink density on the amount and molar ratio of ZnO/MAA was studied and the extraordinary high tensile strength of the EPDM/ZDMA vulcanizate was related to ionic crosslink density. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1339–1345, 2002; DOI 10.1002/app.10112
Thermoplastic elastomers from reclaimed rubber and waste plastics
Authors: Nevatia P. , Banerjee T. S. , Dutta B. , Jha A. , Naskar Amit K. , Bhowmick Anil K.
Published: August 2002

Thermoplastic elastomeric compositions from reclaimed rubber and scrap plastics were prepared. The physical properties, dynamic mechanical properties, rheological behavior, and phase morphology of the blends were studied. A 50:50 rubber/plastic ratio was found to be the best for processability, ultimate elongation, and set properties. A sulfur‐accelerator system was found to be better than a peroxide system for dynamic crosslinking. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2035–2042, 2002
Isothermal and nonisothermal melt‐crystallization kinetics of syndiotactic polystyrene
Authors: Chen Qingyong , Yu Yingning , Na Tianhai , Zhang Hongfang , Mo Zhishen
Published: August 2002

Analyses of the isothermal and nonisothermal melt kinetics for syndiotactic polystyrene have been performed with differential scanning calorimetry, and several kinetic analyses have been used to describe the crystallization process. The regime II→III transition, at a crystallization temperature of 239°, is found. The values of the nucleation parameter Kg for regimes II and III are estimated. The lateral‐surface free energy, σ = 3.24 erg cm−2, the fold‐surface free energy, σe = 52.3 ± 4.2 erg cm−2, and the average work of chain folding, q = 4.49 ± 0.38 kcal/mol, are determined with the (040) plane assumed to be the growth plane. The observed crystallization characteristics of syndiotactic polystyrene are compared with those of isotactic polystyrene. The activation energies of isothermal and nonisothermal melt crystallization are determined to be ΔE = −830.7 kJ/mol and ΔE = −315.9 kJ/mol, respectively. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2528–2538, 2002
In situ preparation of magnesium methacrylate to reinforce NBR
Authors: Yuan Xinheng , Zhang Yong , Peng Zonglin , Zhang Yinxi
Published: August 2002

Magnesium methacrylate (MDMA) was in situ prepared in nitrile rubber (NBR) by reacting magnesium hydroxide (Mg (OH)2) with methacrylic acid (MAA) during the mixing step. The formation of MDMA in NBR was proved by the wide‐angle X‐ray diffraction analysis (WAXD). The mechanical properties, crosslinking structure, and morphology of the resulting peroxide‐cured NBR vulcanizates were studied. Results showed that Mg (OH)2/MAA mixtures had a great reinforcing effect for NBR, and their amounts and ratio played important roles in influencing the ultimate properties. Both the covalent crosslink density and ionic crosslink density of the vulcanizates were measured. And the nano‐composite morphology of such vulcanizates was also observed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1403–1408, 2002; DOI 10.1002/app.10323
Study on mobility of water and polymer chain in epoxy and its influence on adhesion
Authors: Luo Shijian , Leisen Johannes , Wong C. P.
Published: August 2002

This paper presents a study on the mobility of water and polymer chains in epoxy materials and its influence on the rate of adhesion degradation in a humid environment. Solid state nuclear magnetic resonance (NMR) techniques (both 1H NMR and 2H NMR) were used to study the binding states of water within two epoxy formulations along with the possible plasticizing effects of moisture affecting the mobility of polymer chains. Absorbed water reduces the glass transition temperature of polymeric materials. However, the presence of moisture has no significant effect on the polymer chain mobility at temperatures below the reduced glass transition temperature. Water in an epoxy in its rubbery state above the glass transition has a much higher mobility than in a polymer in its glassy state. The mobility of water absorbed by a polymer in its rubbery state is similar to that of pure water. The translational mobility of water within epoxies was studied by measuring the diffusion coefficient of water in epoxies through the water uptake. Higher rotational mobilities of water and polymer chains in the rubbery state lead to a significant increase of the water diffusion coefficient in the rubbery state polymer matrix as compared to a polymer in its glassy state. The higher mobility of absorbed water and the higher mobility of polymer chains in epoxy lead to faster adhesion degradation during aging in a humid environment. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1–8, 2002
Poly(sulfobetaine)s and corresponding cationic polymers. VIII. Synthesis and aqueous solution properties of a cationic poly(methyl iodide quaternized styrene–n,n‐dimethylaminopropyl maleamidic acid) copolymer
Authors: Lee Wen‐Fu , Chen Yan‐Ming
Published: August 2002

A cationic poly(methyl iodide quaternized styrene–N,N‐dimethylaminopropylmaleamidic acid) copolymer was synthesized through amidoacidification reaction of styrene‐maleic anhydride copolymer with N,N‐dimethylaminopropylamine (ring‐opening reaction). Its properties in various aqueous salt solutions and pH solutions were studied by measurements of reduced viscosity and intrinsic viscosity. The results indicated that the reduced viscosity and intrinsic viscosity of this cationic polyelectrolyte were related to the type and concentration of the added salts and the results also showed a contrary tendency in some salts with monovalent acid groups to polyelectrolyte. At the same time, some salt ions were observed to strongly attract the quaternary ammonium group of the cationic polymeric side chain and resulted in agglomeration of the polymers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1619–1626, 2001
Modeling of fractionation in CRYSTAF using Monte Carlo simulation of crystallizable sequence lengths: Ethylene/1‐octene copolymers synthesized with single‐site–type catalysts
Authors: Beigzadeh D. , Soares J. B. P. , Duever T. A.
Published: August 2002

Monte Carlo simulation was used to model the fractionation process in crystallization analysis fractionation (CRYSTAF). Five poly(ethylene/1‐octene) samples synthesized with a single‐site–type catalyst were used to verify the simulation results. It was proposed that the fractionation mechanism be controlled by the crystallization of the longest ethylene sequence in each chain. Good agreement between experimental and simulation results verified the validity of the proposed fractionation mechanism. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2200–2206, 2001
Production of a high‐functionality RBD palm kernel oil‐based polyester polyol
Authors: Badri K. H. , Ahmad S. H. , Zakaria S.
Published: August 2002

A diol‐based refined, bleached, and deodorized (RBD) palm kernel oil polyol was prepared. It was found that the polyurethane foam produced only gives a good compressive strength property at a 45 kg/m3 molded density. The combination of sorbitol into the polyol system resulted in a better dimensional stability and improved thermal conductivity as well as enhanced compressive strength. These were obtained by increasing the functionality of the polyol (functionality of 4.5) through introduction of a high molecular weight and branching polyhidric compound. Direct polycondensation and transesterification methods were used for the syntheses. The hydroxyl value, TLC, and FTIR were used to study the completion of the reaction. A comparative study of the mechanical properties and morphological behavior was carried out with a diol‐based polyol. From the water‐blown molded foam (zero ODP) with a density of about 44.2 kg/m3 and a closed‐cell content of 93%, a compressive strength of 222 kPa and a dimensional stability of 0.09, 0.10, and 0.12% at the length, width, and thickness of the foam, respectively, conditioned at −15°C for 24 h, were obtained. The thermal conductivity improved to an initial value of 0.00198 W/mK, tested at 0°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 384–389, 2001
Synthesis and properties of elastomer‐modified epoxy–methacrylate sequential interpenetrating networks
Authors: Sands J. M. , Jensen R. E. , Fink B. K. , McKnight S. H.
Published: August 2002

The structure and properties of copolymerized sequential‐interpenetrating networks (SeqIPNs) synthesized from amine‐cured epoxies and free‐radical polymerized dimethacrylates were examined. Materials were synthesized with and without the incorporation of an epoxy‐terminated butadiene–nitrile reactive elastomer. Synthesis proceeded through full thermal cure of the epoxy–amine network, followed by polymerization of the methacrylate network. The methacrylate reactions were free‐radically induced using thermal (peroxide‐initiated) or photochemical [electron‐beam (e‐beam)] techniques. Fourier transform infrared spectroscopy was used to monitor epoxy–amine step‐growth polymerization in situ and to measure final cure conversion of methacrylates. Structural examination of the IPNs using atomic force microscopy and scanning electron microscopy revealed microphase separation in the neat–SeqIPN materials and macroscopic phase separation of rubber‐rich domains for elastomer‐modified networks. Dynamic mechanical analysis of the SeqIPN determined that the properties of the network are strongly dependent on the cure conditions. Furthermore, the viscoelastic behavior of the e‐beam–cured SeqIPN could be adequately described by the Williams–Landel–Ferry and Kohrausch–Willams–Watts equations, presumably because of a strong coupling between the epoxy–amine and methacrylate networks. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 530–545, 2001
Effect of a styrene–butadiene copolymer on the phase structure and impact strength of polyethylene/high‐impact polystyrene blends
Authors: Fortelný I. , Michálková D. , Hromádková J. , Lednický F.
Published: August 2002

The effect of a styrene–butadiene block copolymer on the phase structure and impact strength of high‐density and low‐density polyethylene/high‐impact polystyrene blends with various compositions was studied. For both the blends, the type of the phase structure was not affected by addition of a styrene–butadiene compatibilizer. The localization and structure of the compatibilizer in the blends were dependent on their composition. Addition of the compatibilizer improved impact strength of the blends in the whole concentration range. The improvement was the largest for blends with a low amount of the minor phase. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 570–580, 2001
Efficiency of some dinitrodiamines and dinitrodiamides in improving dynamic properties of vulcanized rubber
Authors: Klásek A. , Filipovičová E. , Špaček J.
Published: August 2002

The effect of some dinitrodiamines and dinitrodiamides on dynamic properties of vulcanized rubber have been investigated. Rubber compounds based on NR/BR were used for these experiments. It has been established that only the use of dinitrodiamines contribute to the increase of impact resilience in comparison with the unmodified compound. The results of carbon gel content assessment suggest that, under given conditions, dinitrodiamides do not form bonds between rubber and carbon black and, therefore, do not influence the dynamic properties of vulcanized rubber. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1439–1443, 2001
High‐performance bismaleimide resin film for resin film infusion
Authors: Liang Guozheng , Wang Dong
Published: August 2002

A novel high‐performance resin film, coded 4508B, suitable for the resin film infusion (RFI) process, was developed. It was prepared from 4,4′‐bismaleimidodiphenylmethane (BDM), o,o′‐diallylbisphenol A (BA), polyethersulfone (PES), and polyimide (PI). The resin and its composite, reinforced by glass fiber cloth, were prepared and characterized in detail. The results showed that the resin film was stable at room temperature, its infusion temperature was 120°C, and the pot life was more than 60 min. In addition, the cured resin and the composite prepared by the RFI process had good thermal and mechanical properties and hot‐wet resistance. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2918–2922, 2001
Temperature and atmosphere influences on smoke composition during thermal degradation of poly(ethylene terephthalate)
Authors: Dziȩcioł Małgorzata , Trzeszczyński Jerzy
Published: August 2002

The less‐volatile compounds forming a smoke emitted during the thermal degradation of poly(ethylene terephthalate) (PET) in different conditions were studied. Thermal degradation of PET was carried out within the temperature range of 200–700°C in both a nitrogen and an air atmosphere. The less‐volatile thermal degradation products were trapped on a glass‐fiber filter and analyzed by capillary gas chromatography with mass selective detector (GC‐MS) and high performance liquid chromatography (HPLC). The results are collected in tables and presented on plots as a function of the degradation temperature. The temperature and atmosphere effects on the emission and composition of the smoke during PET thermal degradation were considered. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3064–3068, 2001