bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison among different insulin sensitivity indices in obese patients
Authors: Mannucci E. , Bardini G. , Rotella F. , Rotella C. M.
Published: May 2003

Aims Recently, several indices have been proposed for the measurement of insulin sensitivity (IS). We set out to make a comparison between fasting insulin, and different IS indices in obese subjects.

Patients and methods Fasting and post load (75 g) glucose and insulin were measured in a consecutive series of 767 (626 F, 141 M) obese (body mass index > 30 kg/m2) out‐patients, with no known history of diabetes (DM). Mean (± sd) age was 46.7 ± 13.8 years in females and 45.6 ± 14.3 years in males. Indices of IS based on fasting homeostasis assessment model (HOMA) and post‐load (ISI) glucose and insulin and either parameter (1A, and 1B scores) were determined.

Results DM was diagnosed in 21.4% of females, and 20.6% of males, and impaired glucose tolerance in 24% females and 21.3% males. Fasting and post‐load glucose, triglyceride and HDL‐cholesterol were correlated with all indices in both sexes (P < 0.05). The relative risk of different conditions in the upper quartile of ISI was similar to that observed in the upper quartile of HOMA. The HOMA index was similarly associated with low HDL‐cholesterol and hypertriglyceridaemia as fasting insulin, while it showed a greater association with diabetes; ISI was similarly associated with all three conditions as the HOMA index.

Conclusions Indices of IS based on fasting glucose and insulin show a greater association with diabetes, but not with other abnormalities related to insulin resistance, when compared with fasting insulin levels. Indices based on post‐load glucose and insulin do not offer any advantage over those based on fasting values.

Diabet. Med. 20, 462–466 (2003)
Studies of variability in the islet amyloid polypeptide gene in relation to Type 2 diabetes
Authors: Pildal J. , Lajer M. , Hansen S. K. , Almind K. , Ambye L. , Borch‐Johnsen K. , Carstensen B. , Hansen T. , Pedersen O.
Published: May 2003

Aims To explore whether the coding region of the islet amyloid polypeptide (IAPP) gene contains genetic variants associated with Type 2 diabetes and whether a previously reported association of the promoter variant −132g→a with Type 2 diabetes could be reproduced in Danish Caucasians.

Methods The coding region was analyzed using single strand conformation polymorphism (SSCP) and heteroduplex analysis in 192 Type 2 diabetic patients. Restriction fragment length polymorphism (RFLP) was employed to screen for the promoter variant in 414 Type 2 diabetic patients and 182 glucose‐tolerant control subjects.

Results The SSCP analysis identified an IVS+75a→g variant in two patients. The frequency of heterozygous carriers of the promoter variant in the case–control study was 4.1% (17/414) and 7.1% (13/182), respectively. Odds ratio of the prevalence of Type 2 diabetes in carriers compared with non‐carriers was estimated to be 0.47 (95% confidence interval 0.19, 1.15).

Conclusion Neither variability in the coding region of the IAPP gene nor the −132g→a promoter variant was associated with Type 2 diabetes among the studied Danish Caucasians.

Diabet. Med. 20, 491–494 (2003)
Neuroglycopenia in normoglycaemic patients, and the potential benefit of ketosis
Authors: Willemsen M. A. A. P. , Soorani‐Lunsing R. J. , Pouwels E. , Klepper J.
Published: May 2003

We report a patient with recurrent symptoms of neuroglycopenia due to a defective glucose transport into brain. The potential benefit of ketosis in neuroglycopenia is discussed from the therapeutic concept of a ketogenic diet in GLUT1‐deficiency syndrome.

Diabet. Med. 20, 481–482 (2003)
Serum interleukin‐6 levels and bone mineral density at the femoral neck in post‐menopausal women with Type 1 diabetes
Authors: Rachoń D. , Myśliwska J. , Suchecka‐Rachoń K. , Semetkowska‐Jurkiewicz B. , Zorena K. , Łysiak‐Szydłowska W.
Published: May 2003

Background Although osteopenia is often reported in Type 1 diabetes mellitus, the pathogenic mechanisms are not fully understood. Oestrogen deficiency also leads to decreased bone mineral density (BMD). Enhanced interleukin‐6 (IL‐6) production among Type 1 diabetic patients could be involved in the pathogenesis of diabetic bone loss since it is a potent bone resorbing cytokine.

Aims To evaluate the relationship between serum bioactive IL‐6 levels and BMD at the femoral neck of post‐menopausal women with Type 1 diabetes.

Methods We studied BMD, urine excretion of deoxypirydynoline crosslinks, serum bioactive IL‐6 and soluble IL‐6 receptor (sIL‐6R) levels in 20 post‐menopausal women with Type 1 diabetes mellitus, and compared these results with 20 matched healthy post‐menopausal controls.

Results Post‐menopausal women with Type 1 diabetes had significantly lower BMD at the femoral neck and increased serum bioactive IL‐6 levels compared with the control group, but no relationship was observed between these variables in a multiple regression analysis. Using BMD at the femoral neck of diabetic women as the dependent variable in the multiple step regression analysis model, we found that independent variables that were strongly associated with bone mass at the femoral neck in this group were: time since menopause and duration of diabetes.

Conclusions Although our study had a small sample size, we found that post‐menopausal women with Type 1 diabetes mellitus present lower bone mass and higher serum bioactive IL‐6 levels than matched healthy controls, but we were unable to find a correlation between these two parameters.

Diabet. Med. 20, 475–480 (2003)
The effectiveness of screening for diabetic retinopathy by digital imaging photography and technician ophthalmoscopy
Authors: Scanlon P. H. , Malhotra R. , Thomas G. , Foy C. , Kirkpatrick J. N. , Lewis‐Barned N. , Harney B. , Aldington S. J.
Published: May 2003

Aims To evaluate the introduction of a community‐based non‐mydriatic and mydriatic digital photographic screening programme by measuring the sensitivity and specificity compared with a reference standard and assessing the added value of technician direct ophthalmoscopy.

Methods Study patients had one‐field, non‐mydriatic, 45° digital imaging photography prior to mydriatic two‐field digital imaging photography followed by technician ophthalmoscopy. Of these patients, 1549 were then examined by an experienced ophthalmologist using slit lamp biomicroscopy as a reference standard. The setting was general practices in Gloucestershire. Patients were selected by randomizing groups of patients (from within individual general practices) and 3611 patients were included in the study. Patients for reference standard examination were recruited from groups of patients on days when the ophthalmologist was able to attend. The main outcome measure was detection of referable diabetic retinopathy (DR) as defined by the Gloucestershire adaptation of the European Working Party guidelines.

Results For mydriatic digital photography, the sensitivity was 87.8%, specificity was 86.1% and technical failure rate was 3.7%. Technician ophthalmoscopy did not alter these figures. For non‐mydriatic photography, the sensitivity was 86.0%, specificity was 76.7% and technical failure rate was 19.7%.

Conclusions Two‐field mydriatic digital photography is an effective method of screening for referable diabetic retinopathy. Non‐mydriatic digital photography has an unacceptable technical failure rate and low specificity.

Diabet. Med. 20, 467–474 (2003)
Cardiovascular autonomic neuropathy associated with carotid atherosclerosis in Type 2 diabetic patients
Authors: Gottsäter A. , Rydén‐Ahlgren Å. , Szelag B. , Hedblad B. , Persson J. , Berglund G. , Wroblewski M. , Sundkvist G.
Published: May 2003

Aims To clarify if cardiovascular autonomic neuropathy is associated with carotid artery atherosclerotic plaques in Type 2 diabetic patients.

Methods Cardiovascular autonomic nerve function was related to carotid artery ultrasound in 61 Type 2 diabetic patients 5–6 years after diagnosis of diabetes.

Results Cardiovascular autonomic neuropathy [abnormal age corrected expiration/inspiration (E/I) ratio or acceleration index (AI)] was found in 13/61 (21%) patients. Patients with cardiovascular autonomic neuropathy showed increased degree of stenosis in the common carotid artery (24.6 ± 13.2% vs. 14.7 ± 9.2%; P = 0.014) and a tendency towards a higher plaque score (4.0 ± 1.7 vs. 3.2 ± 1.6; P = 0.064). Controlled for age, AI correlated inversely with degree of stenosis (r = −0.39; P = 0.005), plaque score (r = −0.39; P = 0.005), and mean (r = −0.33; P = 0.018) and maximum (r = −0.39; P = 0.004) intima‐media thickness in the common carotid artery. In contrast, E/I ratio correlated only slightly with mean intima‐media thickness in the common carotid artery (r = −0.28; P = 0.049).

Conclusions Cardiovascular autonomic neuropathy was associated with carotid atherosclerosis in Type 2 diabetic patients. Abnormal E/I ratios reflect efferent structural damage to parasympathetic nerves whereas abnormal AI reflects afferent autonomic dysfunction possibly due to impaired baroreceptor sensitivity secondary to carotid atherosclerosis.

Diabet. Med. 20, 495–499 (2003)
The association between satisfaction with services provided in primary care and outcomes in Type 2 diabetes mellitus
Authors: Alazri M. H. , Neal R. D.
Published: May 2003

Background Patient satisfaction is of increasing importance, is taken into account when planning services, and is used by healthcare providers as a measure of healthcare quality. Satisfaction with medical care, including diabetic care, has been associated with various health‐related behaviours and outcomes that have a direct bearing on health and illness. The association between satisfaction and health outcomes is poorly understood.

Aim The aim of the study was to determine whether there is an association between satisfaction in patients with Type 2 diabetes and the outcome of their diabetic care, and to determine the contribution of different aspects of satisfaction with the primary care.

Methods Patients with Type 2 diabetes were identified from two general practices in Leeds.

Patients scores on the General Practice Assessment Survey Questionnaire (GPAS) were correlated with the outcome of care, as measured by HbA1c level collected from patients’ medical records.

Results Data from 106 patients were analysed. There was a generally high satisfaction rate for all GPAS domains. The correlation between different GPAS domains and HbA1c level showed significant positive correlations (P < 0.001) for continuity of care, trust and overall satisfaction; and positive correlations (P < 0.01) for access, receptionists, interpersonal care, communication skills, knowledge of patient about the doctor, technical care, and practice nursing.

Conclusion The findings from this study demonstrate that there is an association between satisfaction and outcome in diabetes, which goes across all the GPAS domains. This suggests that processes that can act to increase patient satisfaction may be contributing to improved clinical outcomes. More development work is needed in this field to explore and elucidate the complex relationship between satisfaction and clinical outcomes.

Diabet. Med. 20, 486–490 (2003)
Type 1 diabetes in Yorkshire, UK: time trends in 0–14 and 15–29‐year‐olds, age at onset and age‐period‐cohort modelling
Authors: Feltbower R. G. , McKinney P. A. , Parslow R. C. , Stephenson C. R. , Bodansky H. J.
Published: May 2003

Aims To investigate whether the rising incidence of Type 1 diabetes in children is evident in young adults and determine whether age at onset has decreased over time.

Methods Two geographically defined datasets from the population‐based Yorkshire Diabetes Register were analysed: (i) 2718 children diagnosed under 15 years with Type 1 diabetes from 1978 to 2000 in Yorkshire; (ii) 631 young adults (15–29 years) diagnosed from 1991 to 1999 in West Yorkshire. Log‐linear regression and age‐period‐cohort modelling evaluated changes in incidence over time and age at onset.

Results Incidence rose steadily for 0–14‐year‐olds in Yorkshire with an average annual increase of 2.9%[95% confidence interval (CI) 2.0, 3.8]. In West Yorkshire between 1991 and 1999, the time trends for 0–14 and 15–29‐year‐olds were significantly different (P = 0.014). Stable rates in 15–29‐year‐olds contrasted with an average annual increase of 5.9% (95% CI 2.7, 9.2) for 0–14‐year‐olds. The mean age at onset fell from 9.2 to 8.4 years for 0–14‐year‐olds and from 16.0 to 14.6 years for 0–29‐year‐olds. Age‐period‐cohort modelling showed a statistically significant (P < 0.001) increased risk of developing diabetes was associated with decreasing age for those diagnosed more recently.

Conclusions A steady and continuing rise in the incidence of Type 1 diabetes over time is observed for children but not for young adults. In parallel, the age at onset is gradually decreasing and more recent birth cohorts are at increased risk. This overall pattern is consistent with the influence of an environmental agent that is gradually affecting children at younger and younger ages.

Diabet. Med. 20, 437–441 (2003)
Adolescent onset Type 2 diabetes in a non‐obese Caucasian patient with an unbalanced translocation
Authors: Owen K. R. , Roland J. , Smith K. , Hattersley A. T.
Published: May 2003

Background Childhood onset Type 2 diabetes in the UK has been reported in obese, insulin‐resistant subjects. Investigation is necessary to exclude other aetiologies including genetic causes. The co‐existence of diabetes and a chromosomal breakpoint may indicate the position of novel diabetes genes.

Case report We describe a novel unbalanced translocation between Xq and 10p associated with amenorrhoea and onset of Type 2 diabetes in a non‐obese Caucasian adolescent. There was no evidence of an autoimmune or known genetic aetiology for the diabetes and the phenotype was not typical of youth‐onset Type 2. We therefore hypothesize that the translocation is implicated in the aetiology of the diabetes. This is supported by previous reports of diabetes as a feature of Xq deletions and Turner's syndrome and linkage to the Xq region in a genome‐wide scan for Type 2 genes.

Conclusion That this region may harbour a gene predisposing to Type 2 diabetes and that cytogenetic studies may be useful in investigating diabetes in children and young adults.

Diabet. Med. 20, 483–485 (2003)
The vitamin D receptor gene variant and physical activity predicts fasting glucose levels in healthy young men
Authors: Ortlepp J. R. , Metrikat J. , Albrecht M. , Von Korff A. , Hanrath P. , Hoffmann R.
Published: May 2003

Aims Vitamin D can influence lipolysis and insulin secretion. A common genetic polymorphism of the vitamin D receptor (VDR), which has been found to be associated with bone mineral density, has been reported to be also associated with Type 2 diabetes mellitus (DM). To test the influence of the VDR polymorphism on fasting glucose in healthy young men before the onset of Type 2 DM, we studied a homogeneous population of aircrew members.

Methods A total of 1539 individuals were recruited during routine medical qualification for flying duty. Physical activity was assessed in all individuals and categorized into low physical activity (≤ 3 h per week) and high physical activity (> 3 h per week). The BsmI VDR polymorphism was analysed by polymerase chain reaction. On the day of blood testing the individuals were fasting for at least 8 h overnight. Serum glucose was measured within 60 min after sampling venous blood.

Results In young males with low physical activity (n = 752) gene carriers with the VDR genotype BB (n = 137) have significantly (P < 0.001) higher levels of fasting glucose (5.61 ± 0.49 mmol/l) than gene carriers with the genotype Bb (n = 370; 5.44 ± 0.44 mmol/l) or bb (n = 245; 5.38 ± 0.44 mmol/l). Of BB gene carriers, 47% had fasting glucose levels > 5.55 mmol/l compared with 36% of Bb gene carriers and 34% of bb gene carriers (P = 0.018). This effect is absent in gene carriers with high physical activity (n = 787).

Conclusions The VDR genotype is associated with altered fasting glucose levels in young men with low physical activity. If this association is confirmed in other populations it might be worthwhile studying the particular benefits of an exercise programme in dependents of the VDR genotype.

Diabet. Med. 20, 451–454 (2003)
Relationship of lipoprotein(a) with intimal medial thickness of the carotid artery in Type 2 diabetic patients in south India
Authors: Velmurugan K. , Deepa R. , Ravikumar R. , Lawrence J. B. , Anshoo H. , Senthilvelmurugan M. , Enas E. A. , Mohan V.
Published: May 2003

Objective The objective of this study was to investigate the association of lipoprotein(a) [Lp(a)] levels with intimal medial thickness (IMT) in Type 2 diabetic patients in south India.

Study design We studied 587 consecutive Type 2 diabetic patients at the M.V. Diabetes Specialities Centre, Chennai. The mean age of the study group was 55 ± 10 years and 71.2% were males. IMT of the right common carotid artery was determined using high‐resolution B mode ultrasonography. Lp(a) levels were measured using ELISA. Since the frequency distribution of Lp(a) was skewed, Lp(a) values were log transformed and the geometric mean was used for statistical analysis. The tertiles of IMT were determined to analyse the association of Lp(a) and other factors with IMT.

Result The mean Lp(a) level in the study patients was 18.9 ± 3.1 mg/dl (geometric mean ± sd) and the mean IMT of the study subjects was 0.93 ± 0.19 mm (mean ± sd). The prevalence of carotid atherosclerosis (defined as IMT > 1.1 mm) among subjects with elevated Lp(a) levels > 20 mg/dl was significantly higher compared with those with Lp(a) levels ≤ 20 mg/dl (26.9% vs. 16.3%, P = 0.003). Lp(a) levels increased with increase in tertiles of IMT (anova, P < 0.05). Pearson correlation analysis of carotid IMT with other cardiovascular risk factors revealed strong correlation of IMT with age (P < 0.0001), duration of diabetes (P < 0.0001), systolic blood pressure (P < 0.0001), diastolic blood pressure (P = 0.006), LDL‐cholesterol (P = 0.023), HbA1c (P = 0.017) and Lp(a) (P < 0.0001). Multiple logistic regression analysis showed age (P = 0.010), LDL‐cholesterol (P = 0.032) and Lp(a) (P = 0.021) to be associated with carotid atherosclerosis.

Conclusion The results suggest that Lp(a) has a strong association with IMT of carotid arteries in Type 2 diabetic subjects in south India.

Diabet. Med. 20, 455–461 (2003)
Insulin resistance Type A and short 5th metacarpals
Authors: Patel Vinod K. , Davies Huw Alban
Published: May 2003

Background/aims Insulin resistance is associated with a number genetic syndromes and a variety of defects of insulin action.

Methods We describe three members of an extended family spanning two generations with insulin resistance Type A and short 5th metacarpals. The proband had secondary amenorrhoea, male pattern hair distribution, acne, hirsutism, deep voice, acanthosis nigricans, polycystic ovaries, diabetes, features of acromegaly, raised creatine kinase and triglyceride levels and short 5th metacarpals. Her growth hormone, adrenal steroid and testosterone levels were normal. The proband's daughter had severe acne, hirsutism, acanthosis nigricans, polycystic ovaries, raised triglyceride, glucose and testosterone level short metacarpals and normal insulin receptor gene. The proband's son had a muscular build, raised creatine kinase, hypertriglyceridaemia and short 5th metacarpals. His fasting insulin levels were normal but pro‐insulin was raised.

Result/conclusion There are many familial and genetic syndromes associated with insulin resistance. This family was diagnosed as having insulin resistance Type A. This family does not conform entirely to any of the previously described syndromes and a number of family members have the phenotype of short 5th metacarpals, which appears to be associated with the features of insulin resistance Type A.

Diabet. Med. 20, 500–504 (2003)
Creatine therapy provides neuroprotection after onset of clinical symptoms in Huntington's disease transgenic mice
Authors: Dedeoglu Alpaslan , Kubilus James K. , Yang Lichuan , Ferrante Kimberly L. , Hersch Steven M. , Beal M. Flint , Ferrante And Robert J.
Published: June 2003

While there have been enormous strides in the understanding of Huntington's disease (HD) pathogenesis, treatment to slow or prevent disease progression remains elusive. We previously reported that dietary creatine supplementation significantly improves the clinical and neuropathological phenotype in transgenic HD mice lines starting at weaning, before clinical symptoms appear. We now report that creatine administration started after onset of clinical symptoms significantly extends survival in the R6/2 transgenic mouse model of HD. Creatine treatment started at 6, 8, and 10 weeks of age, analogous to early, middle, and late stages of human HD, significantly extended survival at both the 6‐ and 8‐week starting points. Significantly improved motor performance was present in both the 6‐ and 8‐week treatment paradigms, while reduced body weight loss was only observed in creatine‐supplemented R6/2 mice started at 6 weeks. Neuropathological sequelae of gross brain and neuronal atrophy and huntingtin aggregates were delayed in creatine‐treated R6/2 mice started at 6 weeks. We show significantly reduced brain levels of both creatine and ATP in R6/2 mice, consistent with a bioenergetic defect. Oral creatine supplementation significantly increased brain concentrations of creatine and ATP to wild‐type control levels, exerting a neuroprotective effect. These findings have important therapeutic implications, suggesting that creatine therapy initiated after diagnosis may provide significant clinical benefits to HD patients.
Brain edema induced by in vitro ischemia: causal factors and neuroprotection
Authors: MacGregor Duncan G. , Avshalumov Marat V. , Rice Margaret E.
Published: June 2003

Decreased cerebral blood flow, hence decreased oxygen and glucose, leads to ischemic brain injury via complex pathophysiological events, including excitotoxicity, mitochondrial dysfunction, increased intracellular Ca2+, and reactive oxygen species (ROS) generation. Each of these could also contribute to cerebral edema, which is the primary cause of patient mortality after stroke. In vitro brain slices are widely used to study ischemia. Here we introduce a slice model to investigate ischemia‐induced edema. Significant water gain was induced in coronal slices of rat brain by 5 min of oxygen and glucose deprivation (OGD) at 35°C, with progressive edema formation after return to normoxic, normoglycemic medium. Edema increased with increasing injury severity, determined by OGD duration (5–30 min). Underlying factors were assessed using glutamate‐receptor antagonists (AP5/CNQX), blockade of mitochondrial permeability transition [cyclosporin A (CsA) versus FK506], inhibition of Na+/Ca2+ exchange (KB‐R7943), and ROS scavengers (ascorbate, Trolox®, dimethylthiourea, Tempol®). All agents except KB‐R7943 and FK506 significantly attenuated edema when applied after OGD; KB‐R7943 was effective when applied before OGD. Significantly, complete prevention of ischemia‐induced edema was achieved with a cocktail of AP5/CNQX, CsA and Tempol® applied after OGD, which demonstrates the involvement of multiple, additive mechanisms. The efficacy of this cocktail further shows the potential value of combination therapies for the treatment of cerebral ischemia.
Dopaminergic neuronal differentiation from rat embryonic neural precursors by Nurr1 overexpression
Authors: Kim Ju‐Yeon , Koh Hyun Chul , Lee Ji‐Yeon , Chang Mi‐Yoon , Kim You‐Chan , Chung Hee‐Yong , Son Hyeon , Lee Yong‐Sung , Studer Lorenz , McKay Ron , Lee Sang‐Hun
Published: June 2003

In vitroexpanded CNS precursors could provide a renewable source of dopamine (DA) neurons for cell therapy in Parkinson's disease. Functional DA neurons have been derived previously from early midbrain precursors. Here we demonstrate the ability of Nurr1, a nuclear orphan receptor essential for midbrain DA neuron developmentin vivo, to induce dopaminergic differentiation in naïve CNS precursorsin vitro. Independent of gestational age or brain region of origin, Nurr1‐induced precursors expressed dopaminergic markers and exhibited depolarization‐evoked DA releasein vitro. However, these cells were less mature and secreted lower levels of DA than those derived from mesencephalic precursors. Transplantation of Nurr1‐induced DA neuron precursors resulted in limited survival andin vivodifferentiation. No behavioral improvement in apomorphine‐induced rotation scores was observed. These results demonstrate that Nurr1 induces dopaminergic features in naïve CNS precursorsin vitro. However, additional factors will be required to achievein vivofunction and to unravel the full potential of neural precursors for cell therapy in Parkinson's disease.
Use of Arc expression as a molecular marker of increased postsynaptic 5‐HT function after SSRI/5‐HT1A receptor antagonist co‐administration
Authors: Castro Elena , Tordera Rosa M. , Hughes Zoe A. , Pei Qi , Sharp Trevor
Published: June 2003

An increase in central postsynaptic 5‐hydroxytryptamine (5‐HT) function activates expression of activity‐related cytoskeletal protein (Arc). Here, Arc expression was used to test whether, in rats, co‐administration of a 5‐HT re‐uptake inhibitor (paroxetine) and a 5‐HT1A receptor antagonist (WAY 100635) increases postsynaptic 5‐HT function. After pre‐treatment with WAY 100635 (0.3 mg/kg s.c.), paroxetine (5 mg/kg s.c.) caused a threefold increase in 5‐HT in prefrontal cortex microdialysates. In situ hybridization studies found that neither paroxetine (5 mg/kg s.c.) nor WAY 1000635 (0.3 mg/kg s.c.) altered Arc mRNA abundance in any region examined. In contrast, paroxetine (5 mg/kg s.c.) increased Arc mRNA after pre‐treatment with WAY 100635 (0.3 mg/kg s.c.). This increase was apparent in cortical regions (frontal, parietal and cingulate) and caudate nucleus but was absent in hippocampus (CA1). Increases in Arc mRNA were accompanied by an increase in c‐fos mRNA. The increase in Arc expression induced by paroxetine/WAY 100635 was abolished by the 5‐HT synthesis inhibitor, p‐chlorophenylalanine (300 mg/kg i.p., daily for two days). In conclusion, paroxetine and WAY 100635 injected in combination (but not alone) caused a region‐specific, 5‐HT‐mediated increase in Arc expression. These data provide molecular evidence that co‐administration of a 5‐HT re‐uptake inhibitor and 5‐HT1A receptor antagonist increases 5‐HT function at the postsynaptic level.
Proteomic identification of nitrated proteins in Alzheimer's disease brain
Authors: Castegna Alessandra , Thongboonkerd Visith , Klein Jon B. , Lynn Bert , Markesbery William R. , Butterfield D. Allan
Published: June 2003

Nitration of tyrosine in biological conditions represents a pathological event that is associated with several neurodegenerative diseases, such as amyotrophic lateral sclerosis, Parkinson's disease and Alzheimer's disease (AD). Increased levels of nitrated proteins have been reported in AD brain and CSF, demonstrating the potential involvement of reactive nitrogen species (RNS) in neurodegeneration associated with this disease. Reaction of NO with leads to formation of peroxynitrite ONOO–, which following protonation, generates cytotoxic species that oxidize and nitrate proteins. Several findings suggest an important role of protein nitration in modulating the activity of key enzymes in neurodegenerative disorders, although extensive studies on specific targets of protein nitration in disease are still missing.

The present investigation represents a further step in understanding the relationship between oxidative modification of protein and neuronal death in AD. We previously applied a proteomics approach to determine specific targets of protein oxidation in AD brain, by successfully coupling immunochemical detection of protein carbonyls with two‐dimensional polyacrylamide gel electrophoresis and mass spectrometry analysis. In the present study, we extend our investigation of protein oxidative modification in AD brain to targets of protein nitration. The identification of six targets of protein nitration in AD brain provides evidence to the importance of oxidative stress in the progression of this dementing disease and potentially establishes a link between RNS‐related protein modification and neurodegeneration.
Interleukin‐18 induces expression and release of cytokines from murine glial cells: interactions with interleukin‐1β
Authors: Wheeler Rachel D. , Brough David , Le Feuvre Rosalind A. , Takeda Kiyoshi , Iwakura Yoichiro , Luheshi Giamal N. , Rothwell Nancy J.
Published: June 2003

Interleukin (IL)‐18, a member of the IL‐1 cytokine family, is an important mediator of peripheral inflammation and host defence responses. IL‐1 is a key proinflammatory cytokine in the brain, but the role of IL‐18 in the CNS is not yet clear. The objective of this study was to investigate the actions of IL‐18 on mouse glial cells. IL‐18 induced intracellular expression of IL‐1α and proIL‐1β, and release of IL‐6 from mixed glia. Treatment of lipopolysaccharide‐primed microglia with adenosine triphosphate (ATP), an endogenous secondary stimulus, induced IL‐1β and IL‐18 release. Although deletion of the IL‐18 gene did not affect IL‐1β expression or release in this experimental paradigm, IL‐1β knockout microglia released significantly less IL‐18 compared to wild‐type microglia. In addition, ATP induced release of mature IL‐1β from IL‐18‐primed microglia. These data suggest that IL‐18 may contribute to inflammatory responses in the brain, and demonstrate that, in spite of several common features, IL‐18 and IL‐1β differ in their regulation and actions.
Functional consequences of homo‐ but not hetero‐oligomerization between transporters for the biogenic amine neurotransmitters
Authors: Kocabas A. M. , Rudnick G. , Kilic F.
Published: June 2003

Before this study, the human norepinephrine transporter (hNET) was the only member of the biogenic amine neurotransmitter transporter family that had not been demonstrated to be a functional homo‐oligomer. Here, using two forms of the transporter, I155C and hNET‐myc, with distinct antigenicity and inhibitor sensitivity, we demonstrated that hNET exists as a homo‐oligomer. hNET I155C is a functional mutant and is sensitive to inactivation by the sulfhydryl reagent [2‐(trimethylammonium)ethyl]methanethiosulfonate, while hNET‐myc is resistant to inactivation by this reagent. Coimmunoprecipitation of these two forms demonstrated that a physical interaction exists between norepinephrine transporter monomers. Further characterization of this physical interaction has revealed that the activity of norepinephrine transporters depends on interactions between monomers. Because norepinephrine transporters and serotonin transporters are the only two members of the neurotransmitter transporter family endogenously expressed in the cell membrane of the same cells, placental syncytiotrophoblasts, we tested the ability of norepinephrine transporters and serotonin transporters to associate and function in a hetero‐oligomeric form. Similarly, coexpression of hNET‐myc with serotonin transporter‐FLAG showed a physical interaction in coimmunoprecipitation assays. However, coexpression of serotonin and norepinephrine transporters did not sensitize norepinephrine transporter activity to inhibition by citalopram, a selective serotonin transport inhibitor. Thus, the norepinephrine transporter–serotonin transporter physical association did not produce functional consequences. Based on this, we propose that the transporters for biogenic amine neurotransmitters interact functionally in homo‐ but not hetero‐oligomeric forms.
Two serine residues distinctly regulate the rescue function of Humanin, an inhibiting factor of Alzheimer's disease‐related neurotoxicity: functional potentiation by isomerization and dimerization
Authors: Terashita Kenzo , Hashimoto Yuichi , Niikura Takako , Tajima Hirohisa , Yamagishi Yohichi , Ishizaka Miho , Kawasumi Masaoki , Chiba Tomohiro , Kanekura Kohsuke , Yamada Marina , Nawa Mikiro , Kita Yoshiko , Aiso Sadakazu , Nishimoto Ikuo
Published: June 2003

The 24‐residue peptide Humanin (HN), containing two Ser residues at positions 7 and 14, protects neuronal cells from insults of various Alzheimer's disease (AD) genes and Aβ. It was not known why the rescue function of (S14G)HN is more potent than HN by two to three orders of magnitude. Investigating the possibility that the post‐translational modification of Ser14 might play a role, we found that HN with d‐Ser at position 14 exerts neuroprotection more potently than HN by two to three orders of magnitude, whereas d‐Ser7 substitution does not affect the rescue function of HN. On the other hand, S7A substitution nullified the HN function. Multiple series of experiments indicated that Ser7 is necessary for self‐dimerization of HN, which is essential for neuroprotection by this factor. These findings indicate that the rescue function of HN is quantitatively modulated by d‐isomerization of Ser14 and Ser7‐relevant dimerization, allowing for the construction of a very potent HN derivative that was fully neuroprotective at 10 pm against 25 µm Aβ1–43. This study provides important clues to the understanding of the neuroprotective mechanism of HN, as well as to the development of novel AD therapeutics.
Cystatin C colocalizes with amyloid‐β and coimmunoprecipitates with amyloid‐β precursor protein in sporadic inclusion‐body myositis muscles
Authors: Vattemi Gaetano , King Engel W. , McFerrin Janis , Askanas Valerie
Published: June 2003

Cystatin C (CC), an endogenous cysteine protease inhibitor, is accumulated within amyloid‐β (Aβ) amyloid deposits in Alzheimer's disease (AD) brain and was proposed to play a role in the AD pathogenesis. Because the chemo‐morphologic muscle phenotype of sporadic inclusion‐body myositis (s‐IBM) has several similarities with the phenotype of AD brain, including abnormal accumulation of Aβ deposits, we studied expression and localization of CC in muscle biopsies of 10 s‐IBM, and 16 disease‐ and five normal‐control muscle biopsies. Physical interaction of CC with amyloid‐β precursor protein (AβPP) was studied by a combined immunoprecipitation/immunoblotting technique in the s‐IBM muscle biopsies and in AβPP‐overexpressing cultured human muscle fibers. In all s‐IBM muscle biopsies, CC‐immunoreactivity either colocalized with, or was adjacent to, the Aβ‐immunoreactive inclusions in 80–90% of the vacuolated muscle fibers, mostly in non‐vacuolated regions of their cytoplasm. Ultrastructurally, CC immunoreactivity‐colocalized with Aβ on 6–10 nm amyloid‐like fibrils and floccular material. By immunoblotting, CC expression was strongly increased in IBM muscle as compared to the controls. By immunoprecipitation/immunoblotting experiments, CC coimmunoprecipitated with AβPP, both in s‐IBM muscle and in AβPP‐overexpressing cultured normal human muscle fibers. Our studies (i) demonstrate for the first time that CC physically associates with AβPP, and (ii) suggest that CC may play a novel role in the s‐IBM pathogenesis, possibly by influencing AβPP processing and Aβ deposition.
Susceptibility to kainate‐induced seizures under dietary zinc deficiency
Authors: Takeda Atsushi , Hirate Maki , Tamano Haruna , Nisibaba Daisuke , Oku Naoto
Published: June 2003

Zinc homeostasis in the brain is altered by dietary zinc deficiency, and its alteration may be associated with the etiology and manifestation of epileptic seizures. In the present study, susceptibility to kainate‐induced seizures was enhanced in mice fed a zinc‐deficient diet for 4 weeks. When Timm's stain was performed to estimate zinc concentrations in synaptic vesicles, Timm's stain in the brain was attenuated in the zinc‐deficient mice. In rats fed the zinc‐deficient diet for 4 weeks, susceptibility to kainate‐induced seizures was also enhanced. When the release of zinc and neurotransmitters in the hippocampal extracellular fluid of the zinc‐deficient rats was studied using in vivo microdialysis, the zinc concentration in the perfusate was less than 50% of that of the control rats and the increased levels of zinc by treatment with kainate were lower than the basal level in control rats, suggesting that vesicular zinc is responsive to dietary zinc deficiency. The levels of glutamate in the perfusate of the zinc‐deficient rats were more increased than in the control rats, whereas the levels of GABA in the perfusate were not at all increased in the zinc‐deficient rats, unlike in the control rats. The present results demonstrate an enhanced release of glutamate associated with a decrease in GABA concentrations as a possible mechanism for the increased seizure susceptibility under zinc deficiency.
Ether‐linked analogue of 2‐arachidonoylglycerol (noladin ether) was not detected in the brains of various mammalian species
Authors: Oka Saori , Tsuchie Akiko , Tokumura Akira , Muramatsu Mayumi , Suhara Yoshitomo , Takayama Hiroaki , Waku Keizo , Sugiura Takayuki
Published: June 2003

2‐Eicosa‐5′,8′,11′,14′‐tetraenylglycerol (2‐AG ether, HU310, noladin ether) is a metabolically stable ether‐linked analogue of 2‐arachidonoylglycerol (2‐AG), an endogenous cannabinoid receptor ligand. 2‐AG ether has been used as a valuable experimental tool by a number of investigators. Recently, several groups reported that 2‐AG ether is present in mammalian brains. We examined in detail whether 2‐AG ether actually exists in the brains of various mammalian species. We found that 2‐AG ether is not present, at least in an appreciable amount, in the rat brain by gas chromatography‐mass spectrometry analysis and fluorometric high performance liquid chromatography analysis. The level of 2‐AG ether in the rat brain was below 0.2 pmol/g brain, if at all present. Similar results were obtained for the mouse brain, hamster brain, guinea‐pig brain and pig brain. The fact that 2‐AG ether was not detected in the brains of various mammalian species is consistent with the fact that an ether bond is formed through enzymatic replacement of the fatty acyl moiety of 1‐acyl dihydroxyacetone phosphate by a fatty alcohol, the resultant 1‐O‐alkyl dihydroxyacetone phosphate being a common intermediate of the biosynthesis of ether‐linked lipids in mammalian tissues. It is rather questionable whether 2‐AG ether is present in appreciable amounts in the brain and acts as an ‘endogenous’ cannabinoid receptor ligand.
Post‐transcriptional suppression of pathogenic prion protein expression in Drosophila neurons
Authors: Deleault Nathan R. , Dolph Patrick J. , Feany Mel B. , Cook Meghan E. , Nishina Koren , Harris David A. , Supattapone Surachai
Published: June 2003

A wealth of evidence supports the view that conformational change of the prion protein, PrPC, into a pathogenic isoform, PrPSc, is the hallmark of sporadic, infectious, and inherited forms of prion disease. Although the central role played by PrPSc in the pathogenesis of prion disease is appreciated, the cellular mechanisms that recognize PrPSc and modulate its production, clearance, and neural toxicity have not been elucidated. To address these questions, we used a tissue‐specific expression system to express wild‐type and disease‐associated PrP molecules heterologously in Drosophila melanogaster. Our results indicate that Drosophila brain possesses a specific and saturable mechanism that suppresses the accumulation of PG14, a disease‐associated insertional PrP mutant. We also found that wild‐type PrP molecules are maintained in a detergent‐soluble conformation throughout life in Drosophila brain neurons, whereas they become detergent‐insoluble in retinal cells as flies age. PG14 protein expression in Drosophila eye did not cause retinal pathology. Our work reveals the presence of mechanisms in neurons that specifically counterbalance the production of misfolded PrP conformations, and provides an opportunity to study these processes in a model organism amenable to genetic analysis.
The Arg617–Arg618 cleavage site in the C‐terminal domain of PC1 plays a major role in the processing and targeting of the enzyme within the regulated secretory pathway
Authors: Bernard Natacha , Kitabgi Patrick , Rovere‐Jovene Carole
Published: June 2003

The C‐terminal domain of the prohormone convertase PC1 is involved in targeting of the enzyme to secretory granules in neuroendocrine cells and is subsequently processed in this compartment at an Arg617‐Arg618 site. Three other dibasics are found in the C‐terminal domain of mouse PC1. Here, we examined the role of the four dibasics in targeting PC1 to secretory granules. All 15 possible combinations of dibasic mutations were performed. Wild‐type (WT) and mutant PC1 were stably expressed in neuroendocrine PC12 cells that lacked endogenous PC1. Processing, secretion and intracellular localization of PC1 and its mutants were analyzed. Leaving intact Arg617‐Arg618 and mutating any combination of the three other dibasics yielded proteins that were stored and processed in secretory granules, similarly to WT PC1. Mutating Arg617‐Arg618 alone or with any one of the three remaining dibasics generated proteins that were efficiently stored in secretory granules but were not processed further. Mutating Arg617‐Arg618 with more than one of the remaining dibasics produced proteins that reached the TGN but were not stored in secretory granules and exited the cells through the constitutive secretory pathway. These data demonstrate that the Arg617‐Arg618 plays a prominent role in targeting PC1 to secretory granules.
Molecular neuroadaptations in the accumbens and ventral tegmental area during the first 90 days of forced abstinence from cocaine self‐administration in rats
Authors: Lu Lin , Grimm Jeff W. , Shaham Yavin , Hope Bruce T.
Published: June 2003

Cocaine self‐administration is associated with a propensity to relapse in humans and reinstatement of drug seeking in rats after prolonged withdrawal periods. These behaviors are hypothesized to be mediated by molecular neuroadaptations within the mesolimbic dopamine system. However, in most studies of drug‐induced neuroadaptations, cocaine was experimenter‐delivered and molecular measurements were performed after short withdrawal periods. In the present study, rats were trained to self‐administer intravenous cocaine or oral sucrose (a control non‐drug reward) for 10 days (6‐h/day) and were killed following 1, 30, or 90 days of reward withdrawal. Tissues from the accumbens and ventral tegmental area (VTA) were assayed for candidate molecular neuroadaptations, including enzyme activities of cAMP‐dependent protein kinase (PKA) and adenylate cyclase (AC), and protein expression of cyclin‐dependent kinase 5 (cdk5), tyrosine hydroxylase (TH) and glutamate receptor subunits (GluR1, GluR2 and NMDAR1). In the accumbens of cocaine‐trained rats, GluR1 and NMDAR1 levels were increased on days 1 and 90, while GluR2 levels were increased on days 1 and 30, but not day 90; PKA activity levels were increased on days 1 and 30, but not day 90, while AC activity, TH and cdk5 levels were unaltered. In the VTA of cocaine‐trained rats, NMDAR1 levels were increased for up to 90 days, while GluR2 levels were increased only on day 1; TH and Cdk5 levels were increased only on day 1, while PKA and AC activity levels were unaltered. Cocaine self‐administration produces long‐lasting molecular neuroadaptations in the VTA and accumbens that may underlie cocaine relapse during periods of abstinence.
Two novel methods for the determination of CYP1A2 activity using the paraxanthine/caffeine ratio
Authors: Doude van Troostwijk Lous J. A. E. , Koopmans Richard P. , Guchelaar Henk‐Jan
Published: June 2003

Cytochrome P450 1A2 (CYP1A2) plays an important role in drug metabolism. Provocation with caffeine is used to estimate CYP1A2 activity, but in most tests a long period of caffeine abstinence has to be taken into account. We compared two novel methods with the currently applied test.

The pharmacokinetic (PK) parameters of caffeine and paraxanthine were estimated in eight caffeine‐taking healthy volunteers by fitting serum concentration–time data to a two‐compartment PK model. Then a three‐step approach was followed. Step 1: The caffeine administration regimens of three provocation methods, which differ by their periods of abstinence, together with the PK parameters of each volunteer, were entered in a PK simulation program and the molecular ratio of the paraxanthine/caffeine concentration (P/C molratio) of each method was estimated for the individual volunteers. Step 2: For each method a relationship for the population between the caffeine clearance (Clc) and the corresponding P/C molratio was empirically established. Step 3: The true caffeine clearance (Clc tr) of each volunteer, as found by fitting the individual PK curve, was compared for all three methods with the clearance estimated from the individual P/C molratio using the relationship of step 2. The predictive values for Clc of the three methods did not differ significantly from Clc tr. For the three methods the values for bias were 6.7, 4.3 and 3.1%, respectively and for precision they were 12.3, 20.6 and 17.8%.

We conclude that the two novel methods of caffeine provocation show good predictive performance for Clc when compared with the conventional method. Abstaining from caffeine for a long period is not necessary to estimate CYP1A2 activity (using the P/C molratio) accurately.
Differences in the effects of extended‐release aspirin and plain‐formulated aspirin on prostanoids and nitric oxide in healthy volunteers
Authors: De La Cruz J. P. , González‐Correa J. A. , Guerrero A. , Márquez E. , Martos F. , Sánchez de la Cuesta F.
Published: June 2003

This study was designed to evaluate the effects of extended‐release aspirin on platelet aggregation and the production of prostanoids and nitric oxide. The participants in this double blind, randomized and crossover study were 20 healthy volunteers. Interventions were 150 mg of plain‐formulated aspirin (PFASA) and 150 mg of extended‐release aspirin (ERASA). Blood samples were collected before and 10, 20, 60, 120, 240, 480 and 1440 min after the first dose; 3, 7 and 14 days after daily administration and 24 h after the last dose. The main measures were platelet aggregometry, thromboxane B2, 6‐keto‐prostaglandin (PG) F1α and nitric oxide in each control. Platelet aggregation was inhibited by 50% with ERASA, and by 77% with PFASA. No differences were found in chronic treatment. Thromboxane B2 was inhibited more by the latter (51–67%), but 90% inhibition was observed in both groups after 3 days. The levels of 6‐keto‐PGF1α was reduced by 20% with ERASA and by 58% with PFASA. Nitric oxide production increased in both groups, but after 24 h, and 7–14 days, elevated concentrations of nitric oxide were found only in the ERASA. The antiplatelet effects of ERASA provide pharmacological advantages (greater prostacyclin synthesis and prolonged increase in nitric oxide production) over those provided by the plain formulation.