bluuebunny/crossref_metadata_2025 huggingface dataset:
Treatment with extracellular HSP70/HSC70 protein can reduce polyglutamine toxicity and aggregation
Authors: Novoselova Tatiana V. , Margulis Boris A. , Novoselov Sergey S. , Sapozhnikov Alexander M. , Van Der Spuy Jacqueline , Cheetham Michael E. , Guzhova Irina V.
Published: July 2005

The accumulation of insoluble protein aggregates is a feature of neurodegenerative disease. Overexpression of Heat Shock Protein 70 (HSP70) can protect cells with protein aggregates from apoptosis. Another trait of HSP70 is its ability to cross the plasma membrane. Therefore, we purified a preparation of HSP70/HSC70 from bovine muscle and used it in a model of Huntington's disease. Human neuroblastoma SK‐N‐SH cells were transfected with huntington exon 1 with short (25) or long (103) CAG trinucleotide repeats coupled to green flourescent protein (GFP). Cells transfected with the long polyCAG repeat had insoluble protein aggregates and died through apoptosis. Biotinylated HSP70/HSC70 incorporated into the culture medium appeared inside the cells within 3–6 h of incubation. This incorporation correlated with a reduction in apoptotic cells by 40–50%. Confocal microscopy revealed that labelled internalized HSP70/HSC70 co‐localized with the polyglutamine inclusions. The measurement of the number and size of inclusions showed that HSP70/HSC70 was able to reduce both these parameters. A filter trap assay and immunoblotting demonstrated that the introduction of HSP70/HSC70 also decreased protein aggregation. Together with earlier data on the effects of exogenously administered HSP70/HSC70 on cultured cells and on animals, these data show that preparations based on HSP70 may have some potential as therapies for a variety of neurodegenerative pathologies.
Dystroglycan and Kir4.1 coclustering in retinal Müller glia is regulated by laminin‐1 and requires the PDZ‐ligand domain of Kir4.1
Authors: Noël Geoffrey , Belda Marina , Guadagno Eric , Micoud Julien , Klöcker Nikolaj , Moukhles Hakima
Published: July 2005

Inwardly rectifying potassium (Kir) channels in Müller glia play a critical role in the spatial buffering of potassium ions that accumulate during retinal activity. To this end, Kir channels show a polarized subcellular distribution with the predominant channel subunit in Müller glia, Kir4.1, clustered in the endfeet of these cells at the inner limiting membrane. However, the molecular mechanisms underlying their distribution have yet to be identified. Here, we show that laminin, agrin and α‐dystroglycan (DG) codistribute with Kir4.1 at the inner limiting membrane in the retina and that laminin‐1 induces the clustering of α‐DG, syntrophin and Kir4.1 in Müller cell cultures. In addition, we found that α‐DG clusters were enriched for agrin and sought to investigate the role of agrin in their formation using recombinant C‐agrins. Both C‐agrin 4,8 and C‐agrin 0,0 failed to induce α‐DG clustering and neither of them potentiated the α‐DG clustering induced by laminin‐1. Finally, our data reveal that deletion of the PDZ‐ligand domain of Kir4.1 prevents their laminin‐induced clustering. These findings indicate that both laminin‐1 and α‐DG are involved in the distribution of Kir4.1 to specific Müller cell membrane domains and that this process occurs via a PDZ‐domain‐mediated interaction. Thus, in the basal lamina laminin is an essential regulator involved in clearing excess potassium released during neuronal activity, thereby contributing to the maintenance of normal synaptic transmission in the retina.
The POZ/BTB protein NAC1 interacts with two different histone deacetylases in neuronal‐like cultures
Authors: Korutla L. , Wang P. J. , Mackler S. A.
Published: July 2005

NAC1 is a cocaine‐regulated POZ/BTB (Pox virus and Zinc finger/Bric‐a‐brac Tramtrack Broad complex) protein. NAC1 is increased by cocaine selectively in the nucleus accumbens, a CNS region important for drug addiction. NAC1's role in the cell, however, is not known. Each of the two NAC1 isoforms, sNAC1 (short NAC1) and lNAC1 (long NAC1), may serve as corepressors for other POZ/BTB proteins. This study investigated whether sNAC1 and lNAC1 demonstrated protein–protein interactions with other corepressors. Histone deacetylase (HDAC) inhibition reversed sNAC1 and lNAC1 repression of Gal4 luciferase, but only in neuronal‐like cultures. Because these inhibitors do not distinguish among histone deacetylases, two histone deacetylases were selected for further study. HDAC 3 and 4 both demonstrated protein–protein interactions with sNAC1 and lNAC1. This was shown using coimmunoprecipitations, glutathione‐S‐transferase (GST) pulldowns and mammalian two‐hybrids. Importantly, either the POZ domain or NAC1 without the POZ domain can bind these two HDACs. Other corepressors, specifically NCoR (nuclear receptor corepressor), SMRT (silencing mediator for retinoid and thyroid hormone receptor) and mSin3a, do not exhibit protein–protein interactions with sNAC1 and lNAC1. None showed protein–protein interactions in GST pulldowns or mammalian two‐hybrids. Taken together, the results of these experiments indicate sNAC1 and lNAC1 recruit histone deacetylases for transcriptional repression, further enhancing POZ/BTB protein mediated repression.
Antioxidant properties of minocycline: neuroprotection in an oxidative stress assay and direct radical‐scavenging activity
Authors: Kraus Richard L. , Pasieczny Rodger , Lariosa‐Willingham Karen , Turner Mary S. , Jiang Alice , Trauger John W.
Published: July 2005

Minocycline is neuroprotective in animal models of a number of acute CNS injuries and neurodegenerative diseases. While anti‐inflammatory and anti‐apoptotic effects of minocycline have been characterized, the molecular basis for the neuroprotective effects of minocycline remains unclear. We report here that minocycline and a number of antioxidant compounds protect mixed neuronal cultures in an oxidative stress assay. To evaluate the role of minocycline's direct antioxidant properties in neuroprotection, we determined potencies for minocycline, other tetracycline antibiotics, and reference antioxidant compounds using a panel of in vitro radical scavenging assays. Data from in vitro rat brain homogenate lipid peroxidation and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging assays show that minocycline, in contrast to tetracycline, is an effective antioxidant with radical scavenging potency similar to vitamin E. Our findings suggest that the direct antioxidant activity of minocycline may contribute to its neuroprotective effects in some cell‐based assays and animal models of neuronal injury.
Induction of tyrosine hydroxylase in the locus coeruleus of transgenic mice in response to stress or nicotine treatment: lack of activation of tyrosine hydroxylase promoter activity
Authors: Osterhout Cheryl A. , Sterling Carol R. , Chikaraishi Dona M. , Tank A. William
Published: July 2005

Prolonged stress or chronic nicotine administration leads to induction of tyrosine hydroxylase (TH) in adrenal medulla and locus coeruleus (LC) of the rat. In this study we use mice that express a transgene encoding 4.5 kb of TH gene 5′‐flanking region fused upstream of the reporter gene, human alkaline phosphatase (hAP) to test whether TH gene promoter activity is stimulated by immobilization stress, cold exposure or nicotine administration in adrenal medulla and LC. TH‐hAP transgene expression is increased in response to all three stimuli in the adrenal medulla. In contrast, TH‐hAP expression does not increase in response to either immobilization stress or nicotine administration in the LC and only a small induction of LC TH‐hAP mRNA is observed in response to cold exposure. TH mRNA is induced 2–3 fold and TH activity is increased significantly by all three stimuli in both the adrenal and LC. These results support the hypothesis that TH expression is induced by stress or nicotine treatment in both the adrenal medulla and LC of the mouse. The induction in the adrenal is dependent primarily on transcriptional mechanisms, whereas that in the LC is apparently dependent primarily on post‐transcriptional mechanisms.
Age‐associated changes in mRNA levels of Phox2, norepinephrine transporter and dopamine β‐hydroxylase in the locus coeruleus and adrenal glands of rats
Authors: Zhu Meng‐Yang , Wang Wei‐Ping , Iyo Abiye H. , Ordway Gregory A. , Kim Kwang‐Soo
Published: July 2005

Age‐related changes in the gene expression of the transcription factors, Phox2a and 2b, and two marker proteins, norepinephrine transporter (NET) and dopamine β‐hydroxylase (DBH), of noradrenergic neurons were characterized in the locus coeruleus (LC) and adrenal glands using in situ hybridization. Analysis of changes was performed in rats that were 1–23 months of age. Compared to 1‐month‐old rats, there was a 62% increase of Phox2a messenger RNA (mRNA) in the LC of 3‐month‐old rats, and a decline of 37% in 23‐month‐old rats. In contrast, levels of Phox2b mRNA in the LC remained unchanged in 3‐month‐old rats, but declined to a 30% reduction in 23‐month‐old rats. Interestingly, mRNA levels of NET in the LC decreased with increasing age to a reduction of 29%, 30% and 43% in 3‐, 8‐ and 23‐month‐old rats, respectively. Similarly, DBH mRNA in the LC declined with increasing age to a 56% reduction in 23‐month‐old rats. mRNA levels of Phox2a, Phox2b, NET and DBH in the adrenal medulla of 23‐month‐old rats were significantly lower than those of 1‐month‐old rats. Semi‐quantitative reverse transcription assays of the same genes yielded data similar to in situ hybridization experiments, with β‐actin mRNA levels being unchanged across the ages. Taken together, these data reveal that reduced Phox2 mRNAs in the LC and adrenal medulla of aging rats are accompanied by a coincidental decline in mRNA levels of NET and DBH and suggest a possible relationship between Phox2 genes and the marker genes in noradrenergic neurons after birth.
Proteolytic degradation of glutamate decarboxylase mediates disinhibition of hippocampal CA3 pyramidal cells in cathepsin D‐deficient mice
Authors: Shimizu Tokiko , Hayashi Yoshinori , Yamasaki Ryo , Yamada Jun , Zhang Jian , Ukai Kiyoharu , Koike Masato , Mine Kazunori , Von Figura Kurt , Peters Christoph , Saftig Paul , Fukuda Takaichi , Uchiyama Yasuo , Nakanishi Hiroshi
Published: July 2005

Although of clinical importance, little is known about the mechanism of seizure in neuronal ceroid lipofuscinosis (NCL). In the present study, we have attempted to elucidate the mechanism underlying the seizure of cathepsin D‐deficient (CD–/–) mice that show a novel type of lysosomal storage disease with a phenotype resembling late infantile NCL. In hippocampal slices prepared from CD–/– mice at post‐natal day (P)24, spontaneous burst discharges were recorded from CA3 pyramidal cells. At P24, the mean amplitude of IPSPs after stimulation of the mossy fibres was significantly smaller than that of wild‐type mice, which was substantiated by the decreased level of γ‐aminobutyric acid (GABA) contents in the hippocampus measured by high‐performance liquid chromatography (HPLC). At this stage, activated microglia were found to accumulate in the pyramidal cell layer of the hippocampal CA3 subfield of CD–/– mice. However, there was no significant change in the numerical density of GABAergic interneurons in the CA3 subfield of CD–/– mice at P24, estimated by counting the number of glutamate decarboxylase (GAD) 67‐immunoreactive somata. In the hippocampus and the cortex of CD–/– mice at P24, some GABAergic interneurons displayed extremely high somatic granular immunoreactivites for GAD67, suggesting the lysosomal accumulation of GAD67. GAD67 levels in axon terminals abutting on to perisomatic regions of hippocampal CA3 pyramidal cells was not significantly changed in CD–/– mice even at P24, whereas the total protein levels of GAD67 in both the hippocampus and the cortex of CD–/– mice after P24 were significantly decreased as a result of degradation. Furthermore, the recombinant human GAD65/67 was rapidly digested by the lysosomal fraction prepared from the whole brain of wild‐type and CD–/– mice. These observations strongly suggest that the reduction of GABA contents, presumably because of lysosomal degradation of GAD67 and lysosomal accumulation of its degraded forms, are responsible for the dysfunction of GABAergic interneurons in the hippocampal CA3 subfield of CD–/– mice.
Calorie restriction delays lipid oxidative damage in Drosophila melanogaster
Authors: Zheng Jianyu , Mutcherson Raye , Helfand Stephen L.
Published: July 2005

The oxidative stress hypothesis predicts that the accumulation of oxidative damage to a variety of macromolecules is the molecular trigger driving the process of aging. Although an inverse relationship between oxidative damage and lifespan has been established in several different species, the precise relationship between oxidative damage and aging is not fully understood. Drosophila melanogaster is a favored model organism for aging research. Environmental interventions such as ambient temperature and calorie restriction can alter adult lifespan to provide an excellent system to examine the relationship between oxidative damage, aging and lifespan. We have developed an enzyme‐linked immunosorbent assay (ELISA) using commercially available reagents for measuring 4‐hydroxy‐2‐nonenal (HNE) in proteins, a marker for oxidative damage to lipids, and present data in flies to show that HNE adducts accumulate in an age‐dependent manner. With immunohistology, we also find the primary site of HNE accumulation is the pericerebral fat body, where induction of dFOXO was recently shown to retard aging. When subjected to environmental interventions that shorten lifespan, such as elevated ambient temperature, the chronological accumulation of HNE adduct is accelerated. Conversely, interventions that extend lifespan, such as lower ambient temperature or low calorie diets, slow the accumulation of HNE adduct. These studies associate damage from lipid peroxidation with aging and lifespan in Drosophila and show that calorie restriction in flies, as in mammals, slows the accumulation of lipid related oxidative damage.
HIF‐1α cytoplasmic accumulation is associated with cell death in old rat cerebral cortex exposed to intermittent hypoxia
Authors: Rapino Cinzia , Bianchi Giuseppina , Di Giulio Camillo , Centurione Lucia , Cacchio Marisa , Antonucci Adriano , Cataldi Amelia
Published: July 2005

Intermittent hypoxia, followed by reoxygenation, determines the production of reactive oxygen species (ROS), which may lead to accelerated aging and to the appearance of age‐related diseases. The rise in ROS levels might constitute a stress‐stimulus activating specific redox–sensitive signalling pathways, so inducing either damaging or protective functions. Here, we report that in old rat cerebral cortex exposed to hypoxia, the accumulation in the cytoplasm of hypoxic inducible factor 1α (HIF‐1α) – the master regulator of oxygen homeostasis – concomitant with p66Shc activation and reduced IkBα phosphorylation is associated with tissue apoptosis or necrosis. In young cerebral cortex, we hypothesize that the hypoxic damage may be reversible, based on our demonstration of elevated HIF‐1α levels, combined with a low level of IkBα phosphorylation, a decrease in IAP‐1 and a lack of major change in Bcl2 family proteins. These observations are associated with a low level of cell death induced by hypoxia, suggesting that HIF‐1α activation in cortical neurons may produce rescue proteins in response to intermittent hypoxia.
Caspase‐independent cytochrome c release is a sensitive measure of low‐level apoptosis in cell culture models
Authors: Goldstein Joshua C. , Rodier Francis , Garbe James C. , Stampfer Martha R. , Campisi Judith
Published: July 2005

Age‐associated loss of tissue function and several chronic diseases may derive in part from the cumulative effects of subtle changes in the level of apoptotic cell death. Because apoptosis is rapid and undetectable once complete, small changes in its incidence are difficult to detect, even in well‐controlled cell cultures. We describe a new apoptosis assay that provides greater sensitivity than conventional assays because it measures the accumulation of apoptotic cells. Human and mouse fibroblasts and human mammary epithelial cells that initiated apoptosis were preserved for 3 days by inhibiting caspase activity using the chemical inhibitor Q‐VD‐OPH (QVD). Cells suspended in the process of apoptosis were scored by immunostaining for cytochrome c, which redistributed from mitochondria in healthy cells to the cytoplasm in dying cells. This caspase‐independent cytochrome c release (CICR) assay was more sensitive than several conventional assays when apoptosis was induced by actinomycin D, and detected cumulative background levels of apoptosis over a 3‐day interval. Using this assay, we show that normal fibroblasts undergo very little apoptosis upon X‐irradiation, indicating dominance of the senescence response in this cell type. Further, apoptosis increased subtly but measurably when human mammary epithelial and skin fibroblast cells entered crisis, indicating that cell death during crisis is largely non‐apoptotic.
An Algorithm for the Physical Examination of Early Fistula Failure
Authors: Beathard Gerald A.
Published: July 2005

Evaluation of a newly created fistula 4–6 weeks after surgery should be considered mandatory. If the fistula is going to become adequate for dialysis, it will be apparent at this time. This evaluation can be accomplished by physical examination. However, it must be performed by someone who is knowledgeable. Using a systematic approach facilitates the evaluation and ensures that a problem is not overlooked. Once it is determined that the fistula is dysfunctional, the case should be immediately referred for management to an interventionalist who is experienced in dealing with early fistula failure. The majority of these cases can be salvaged.
VITAMIN D IN HEALTH AND DISEASE: Vitamin D for Health and in Chronic Kidney Disease
Authors: Holick Michael F.
Published: July 2005

Vitamin D is taken for granted and is not appreciated for its importance in overall health and well‐being. Vitamin D, known as the sunshine vitamin, is appreciated as being important for the prevention of rickets in children. It is now recognized that vitamin D is important for not only the growing skeleton, but for the maintenance of a healthy musculoskeletal system throughout life. Vitamin D deficiency in adults precipitates and exacerbates osteoporosis and causes the painful bone disease osteomalacia. The revelation that vitamin D is biologically inactive and requires sequential hydroxylations in the liver and kidney to form 1,25‐dihydroxyvitamin D helps explain why patients with renal failure are often resistant to vitamin D and suffer from secondary hyperparathyroidism and renal osteodystrophy. In addition to its role in maintaining calcium and phosphorus homeostasis, vitamin D is now being recognized as important for maintaining maximum muscle strength and for the prevention of many chronic diseases, including type I diabetes, multiple sclerosis, rheumatoid arthritis, hypertension, cardiovascular heart disease, and many common cancers. Vitamin D status is best determined by the measurement of circulating levels of 25‐hydroxyvitamin D. Vigilance for maintaining a 25‐hydroxyvitamin D level of at least 20 ng/ml and preferably 30–50 ng/ml has important benefits for both healthy children and adults, as well as children and adults suffering from chronic kidney disease.
VITAMIN D IN HEALTH AND DISEASE: Role of Parathyroid Hormone and Therapy with Active Vitamin D Sterols in Renal Osteodystrophy
Authors: Hernandez Joel D. , Wesseling Katherine , Salusky Isidro B.
Published: July 2005

Renal osteodystrophy (ROD) represents a spectrum of bone lesions ranging from a high‐turnover to a low‐turnover state. The expression of the histologic bone lesions is modulated by parathyroid hormone (PTH), vitamin D, calcium, phosphorus, and aluminum that act as major regulators of osteoblastic activity and bone formation rate. The availability of immunometric PTH assays has allowed reasonable prediction of the subtypes of bone lesions in patients with chronic kidney disease (CKD). PTH levels as measured by these assays, however, may not reflect the true bone turnover state during treatment with intermittent active vitamin D. Early diagnosis and appropriate treatment of renal bone disease are essential in preventing the debilitating consequences of ROD on the growing skeleton. Calcitriol and calcium‐containing phosphate binders have been the mainstay of treatment for secondary hyperparathyroidism. Complications such as hypercalcemia, vascular calcifications, and the development of adynamic bone may arise from aggressive treatment. New vitamin D analogs and calcium‐free phosphate binders are promising in terms of limiting these complications. The management of ROD should be tailored to maintain normal rates of bone formation and turnover with age‐appropriate serum calcium and phosphorus levels and with serum PTH levels that correspond to normal rates of skeletal remodeling. These treatment goals would maintain bone health, maximize growth potential, and prevent the development of soft tissue and vascular calcifications.
VITAMIN D IN HEALTH AND DISEASE: The Evolution of Assays for Parathyroid Hormone
Authors: Goodman William G.
Published: July 2005

Reliable measurements of the concentration of parathyroid hormone (PTH) in serum or plasma are crucial for the effective clinical management of patients with chronic kidney disease (CKD). New PTH assays that increase the specificity of such measurements are now available and are widely utilized. The current review summarizes key technical developments in the evolution of PTH assays. We also discuss the diagnostic value of various methods for measuring PTH in serum or plasma for the assessment of patients with renal bone disease.
“A 30% Chance of Rain Tomorrow”: How Does the Public Understand Probabilistic Weather Forecasts?
Authors: Gigerenzer Gerd , Hertwig Ralph , Van Den Broek Eva , Fasolo Barbara , Katsikopoulos Konstantinos V.
Published: July 2005

The weather forecast says that there is a “30% chance of rain,” and we think we understand what it means. This quantitative statement is assumed to be unambiguous and to convey more information than does a qualitative statement like “It might rain tomorrow.” Because the forecast is expressed as a single‐event probability, however, it does not specify the class of events it refers to. Therefore, even numerical probabilities can be interpreted by members of the public in multiple, mutually contradictory ways. To find out whether the same statement about rain probability evokes various interpretations, we randomly surveyed pedestrians in five metropolises located in countries that have had different degrees of exposure to probabilistic forecasts––Amsterdam, Athens, Berlin, Milan, and New York. They were asked what a “30% chance of rain tomorrow” means both in a multiple‐choice and a free‐response format. Only in New York did a majority of them supply the standard meteorological interpretation, namely, that when the weather conditions are like today, in 3 out of 10 cases there will be (at least a trace of) rain the next day. In each of the European cities, this alternative was judged as the least appropriate. The preferred interpretation in Europe was that it will rain tomorrow “30% of the time,” followed by “in 30% of the area.” To improve risk communication with the public, experts need to specify the reference class, that is, the class of events to which a single‐event probability refers.
Some Limitations of Qualitative Risk Rating Systems
Authors: Cox Louis Anthony (Tony) , Babayev Djangir , Huber William
Published: July 2005

Qualitative systems for rating animal antimicrobial risks using ordered categorical labels such as “high,”“medium,” and “low” can potentially simplify risk assessment input requirements used to inform risk management decisions. But do they improve decisions? This article compares the results of qualitative and quantitative risk assessment systems and establishes some theoretical limitations on the extent to which they are compatible. In general, qualitative risk rating systems satisfying conditions found in real‐world rating systems and guidance documents and proposed as reasonable make two types of errors: (1) Reversed rankings, i.e., assigning higher qualitative risk ratings to situations that have lower quantitative risks; and (2) Uninformative ratings, e.g., frequently assigning the most severe qualitative risk label (such as “high”) to situations with arbitrarily small quantitative risks and assigning the same ratings to risks that differ by many orders of magnitude. Therefore, despite their appealing consensus‐building properties, flexibility, and appearance of thoughtful process in input requirements, qualitative rating systems as currently proposed often do not provide sufficient information to discriminate accurately between quantitatively small and quantitatively large risks. The value of information (VOI) that they provide for improving risk management decisions can be zero if most risks are small but a few are large, since qualitative ratings may then be unable to confidently distinguish the large risks from the small. These limitations suggest that it is important to continue to develop and apply practical quantitative risk assessment methods, since qualitative ones are often unreliable.
A Disciplinary Perspective on the Epistemological Status of Risk
Authors: Althaus Catherine E.
Published: July 2005

A unique multidisciplinary perspective on the risk literature is used to establish a fresh and provocative argument regarding the epistemological understanding and definition of risk. Building on economic conceptualizations that distinguish risk from uncertainty and argue that risk is an ordered application of knowledge to the unknown, the survey identifies each of the disciplines as having a particular knowledge approach with which they confront the unknown so as to order its randomness and convert it into a risk proposition. This epistemological approach suggests the concept of risk can act as a mirror, reflecting the preoccupations, strengths, and weaknesses of each discipline as they grapple with uncertainty. The conclusion suggests that the different disciplines can, and desirably should, act in concert toward a cumulative appreciation of risk that progresses our understanding of the concept. One way in which the article challenges risk experts to join disciplinary forces in a collaborative effort is to holistically appreciate and articulate the concept of political risk calculation.
Abnormalities of Ventricular Repolarization in Mitral Valve Prolapse
Authors: Digeos‐Hasnier Sophie , Copie Xavier , Paziaud Olivier , Abergel Eric , Guize Louis , Diebold Benoît , Jeunemaître Xavier , Berrebi Alain , Piot Olivier , Lavergne Thomas , Le Heuzey Jean‐Yves
Published: July 2005

Objectives: Mitral valve prolapse (MVP) is associated with arrhythmias and sudden death. Some studies suggest that abnormalities of the autonomic nervous system (ANS) may contribute to these arrhythmias. In a family investigation with genetic analysis of patients carrying a MVP, we performed a Holter study to define the autonomic profile of MVP.

Methods and Results: A 24‐hour digitized 3‐lead Holter ECG was recorded in 30 patients with MVP and in two control groups, a group of 30 healthy relatives and a group of 31 healthy volunteers. We studied especially heart rate variability (HRV) and QT dynamicity. The slope of the relationship between ventricular repolarization and heart rate was studied separately during day and night. There was no difference in HRV (SDNN, rMSSD) among the three groups. On the contrary, QT interval duration was increased in patients with MVP as compared to healthy relatives (QT end: 409 ± 52 ms vs 372 ± 23 ms, P < 0.05; QT apex: 319 ± 42 ms vs 286 ± 23 ms, P < 0.01) and to healthy volunteers (QT end: 409 ± 52 ms vs 376 ± 25 ms, P = 0.004; QT apex: 319 ± 42 ms vs 289 ± 23 ms, P < 0.01). Nocturnal ventricular repolarization rate dependence was increased in MVP as compared to healthy relatives (0.16 ± 0.06 vs 0.13 ± 0.04, P < 0.05) and to healthy volunteers (0.16 ± 0.06 vs 0.11 ± 0.06, P < 0.001) whereas the 24‐hour and diurnal QT–R‐R slope was not disturbed.

Conclusion: In MVP, QT is increased and the circadian modulation of QT end/RR slope is disturbed with an increased nocturnal rate dependence. These abnormalities of ventricular repolarization might explain the risk of arrhythmic events in MVP.
Brief Review of the Recently Described Short QT Syndrome and Other Cardiac Channelopathies
Authors: Pérez Riera Andrés Ricardo , Ferreira Celso , Dubner Sergio J , Schapachnik Edgardo , Soares Joaquim D. , Francis Johnson
Published: July 2005

There are many diseases related to ion‐channel disorders, so‐called “channelopathies.” Hereditary short QT syndrome is a clinical‐electrocardiographic entity with autosomal‐dominant mode of transmission and it is the most recently described channelopathy. The syndrome may affect infants, children, or young adults with strong positive family background of sudden cardiac death. Short QT syndrome is characterized by short QT and heart‐rate‐corrected QTc intervals. It is frequently associated with tall‐, peaked‐, and narrow‐based T waves that are reminiscent of the typical “desert tent” T waves of hyperkalemia. There is a high tendency for paroxysmal atrial fibrillation due to the heterogeneous abbreviation of action potential duration and refractoriness of atrial myocytes. The arrhythmia can also be induced by programmed electrical stimulation.

The safest treatment suggested is an implantable cardioverter defibrillator, though the possibilities of inappropriate shocks have caused some concern, especially in teenagers.

The ability of quinidine to prolong the QT interval has the potential to be an effective therapy for patients with short QT syndrome. This is particularly important in developing countries, where the implantable cardioverter‐defibrillator therapy is not always available. Since these patients are at risk of sudden cardiac death from birth, and implantable cardioverter‐defibrillator implantation has a lot of limitations in very young children, the utility of quinidine has to be evaluated further. Clinicians need to be aware of this deadly electrocardiographic (ECG) pattern as it portends a high risk of sudden cardiac death in otherwise healthy subjects with structurally normal hearts.
Cigarette Smoking and Heart Rate Variability: Dynamic Influence of Parasympathetic and Sympathetic Maneuvers
Authors: Barutcu Irfan , Esen Ali Metin , Kaya Dayimi , Turkmen Muhsin , Karakaya Osman , Melek Mehmet , Esen Ozlem Batukan , Basaran Yelda
Published: July 2005

Background: Cigarette smoking has been associated with increased activity of the sympathetic nervous system. In this study, we investigated cardiac autonomic function in heavy smokers and nonsmoker controls by analysis of heart rate variability (HRV).

Method: Twenty‐four long‐term heavy smokers (men) and twenty‐two nonsmoker subjects (hospital staff) were included to study. Time domain [mean R‐R interval (RR), the standard deviation of R‐R interval index (SDNN), and the root mean square of successive R‐R interval differences (RMSSD)] and frequency domain [high frequency (HF) low frequency (LF), and LF/HF ratio] parameters of HRV were obtained from all participants after 15 minutes resting period in supine position (S), during controlled respiration (CR), and handgrip exercise (HGE) over 5‐minute periods.

Results: Baseline SDNN and RMSSD values were found to be lower in smokers than in nonsmokers. (64 ± 10 vs 78 ± 22, P < 0.05 and 35 ± 12 vs 54 ± 30 ms, P < 0.05). Baseline LF/HF ratio was also found to be higher in smokers than in nonsmokers (1.3 ± 0.6 vs 0.9 ± 0.5 ms, P < 0.05). The other HRV parameters including R‐R interval, LF, and HF were not significantly different. During CR, expected increase in RR, SDNN, and RMSSD did not occur in smokers, while it did occur in nonsmokers. Most HRV indices were significantly affected by HGE in both groups. In addition, the duration of smoking was found to be inversely correlated with RMSSD and HF and positively correlated with LF/HF ratio.

Conclusion: Vagal modulation of the heart is blunted in heavy smokers, particularly during a parasympathetic maneuver. Blunted autonomic control of the heart may partly be associated with adverse event attributed to cigarette smoking.
Pacemaker Memory Data Compared to Twenty‐Four‐Hour Holter Monitoring in Patients with VVI Pacemakers and Chronic Atrial Fibrillation
Authors: Chudzik Michal , Wranicz Jerzy Krzysztof , Cygankiewicz Iwona , Goch Jan Henryk , Kargul Wlodzimierz
Published: July 2005

Background: In light of the results from the AFFIRM trial, the “rate control” strategy has become an accepted treatment modality for patients with atrial fibrillation (AF). Establishing effective rate control requires long‐term monitoring of the heart rate. The aim of the study was to compare the heart rate and rhythm monitoring capabilities of the pacemaker memory data (PMD) algorithm and traditional twenty‐four‐hour Holter monitoring.

Methods: The study included 55 patients with chronic AF and a permanent VVI pacemaker. The mean and maximum heart rate as well as the percentage of sensed and paced events obtained from the twenty‐four‐hour Holter were compared with the results retrieved from PMD, started simultaneously. The study was performed over two consecutive days with pacemakers programmed in VVI 40 and 80 bpm mode.

Results: Data retrieved from PMD regarding percentage of sensed and paced episodes as well as mean heart rate strongly correlated with data obtained from twenty‐four‐hour Holter monitoring. The maximum heart rate reported by PMD was significantly higher than that found in the Holter.

Conclusions: PMD provides accurate information regarding long‐term monitoring of heart rate in patients with AF who have an implanted permanent pacemaker and thus may facilitate optimized drug therapy to achieve rate control of AF.
Evaluation of the behavioural response of the flies Megaselia halterata and Lycoriella castanescens to different mushroom cultivation materials
Authors: Tibbles L.L. , Chandler D. , Mead A. , Jervis M. , Boddy L.
Published: July 2005

A static‐air olfactometer was used to investigate the behavioural responses of adult female phorid [Megaselia halterata (Wood) (Diptera: Phoridae)] and sciarid [Lycoriella castanescens (Lengersdorf) (Diptera: Sciaridae)] flies to the commercial white mushroom, Agaricus bisporus (Lange) Imbach, grown on a standard pasteurised composted substrate. The attraction of the flies was measured in relation to four test materials: composted substrate spawned with A. bisporus mycelium for 4 days and 14 days, uncolonised composted substrate, and A. bisporus sporophores. The experiment was done according to a 4 × 4 × 4 Latin cube design, and the results were analysed using a generalised linear model. It was found that both the occasion on which a bioassay was run and the position of the olfactometer within a 4 × 4 array could affect the proportion of the fly population responding to a test material. Megalesia halterata preferred spawned compost to unspawned compost, and the level of response to compost spawned for 14 days was greater than to compost spawned for 4 days. In contrast, L. castanescens were attracted equally to all of the materials tested. Overall, L. castanescens showed a greater level of activity than M. halterata, and was more likely to enter the pitfall traps in the olfactometer. For both M. halterata and L. castanescens, the type of test material affected the numbers of adult flies of the F1 generation that emerged from it following oviposition. The highest numbers of emerging M. halterata were obtained from a composted substrate spawned for 4 days, and none emerged from the unspawned compost. Emergence of L. castanescens was highest from the uncolonised composted substrate, and there was a negative relationship between emergence and the amount of mycelium in the composted substrate. The results are consistent with the use of volatiles in the detection of oviposition sites by both species; however, further studies of the materials will be necessary to determine precisely which oviposition cues the insects use.
The impact of cataract severity on measurement acquisition with the IOLMaster
Authors: Freeman Graham , Pesudovs Konrad
Published: July 2005

Purpose:  The Zeiss IOLMaster optical biometry system provides superior prediction of refractive outcome of cataract surgery compared to applanation ultrasound. However, measurement is not always possible in the presence of dense cataract. The purpose of this study was to elucidate the rate of measurement acquisition failure due to cataract and how this varies with morphology and severity.

Methods:  A total of 149 subjects were prospectively enrolled and visual acuity, Lens Opacities Classification System III (LOCS III) scores, ultrasonic A‐scan and IOLMaster axial lengths were measured. Chi‐squared analysis was used to test the null hypothesis that cataract severity has no effect on measurement failure rate.

Results:  Measurements could not be obtained with the IOLMaster in nine cases for reasons other than cataract. Cataract caused measurement acquisition failure in 22 (15.9%) cases, including all mature cataracts (n = 3) and posterior subcapsular cataracts (PSC) with LOCS III (p > 3.5; n = 18). The null hypothesis was accepted for cortical (χ2 = 2.94, d.f. = 2, p > 0.05) and nuclear (χ2 = 7.91, d.f. = 4, p > 0.05) cataract, but rejected for PSC (χ2 = 111, d.f. = 3, p < 0.001). All cases could be measured with ultrasound.

Conclusions:  The IOLMaster fails to acquire axial length measurement in approximately 20% of UK public hospital cataract patients. Failure is principally due to PSC, whereby the LOCS III score of p = 3.5 defines the limit of PSC severity that the IOLMaster can measure.
Group IIA phospholipase A2 concentration of tears in patients with ocular rosacea
Authors: Kari Osmo , Aho Valtteri V. , Peltonen Sirje , Saari Jukka M. , Kari Marjatta , Määttä Marko , Collan Yrjö , Saari K. Matti
Published: July 2005

Purpose:  To determine the concentration of group IIA phospholipase A2 (GIIAPLA2) in tears of patients with ocular rosacea, and to compare it with GIIAPLA2 concentration in tears of age‐matched healthy controls.

Methods:  The GIIAPLA2 concentration in tears was measured with a time‐resolved fluoroimmunoassay in 21 patients with ocular rosacea (mean age 55.6±9.2 years) and in 21 normal subjects (mean age 53.4±8.2 years). Conjunctival brush cytology was carried out and eosinophils, neutrophils, lymphocytes, squamous epithelial cells, columnar epithelial cells, metaplastic changes and goblet cells were calculated separately.

Results:  The GIIAPLA2 concentration in tears was statistically significantly lower in patients with ocular rosacea (31.0±18.4 µg/ml, p=0.0099) and, more specifically, in patients who had dry eye (25.8±15.1 µg/ml, p=0.0034), compared to that in normal controls. There was no correlation between the GIIAPLA2 content of tears and the conjunctival cells collected by the brush cytology.

Conclusion:  The tears of patients with dry eye symptoms due to ocular rosacea have decreased GIIAPLA2 content. The pathogenic importance of this finding is discussed.
Congenital mydriasis combined with aneurysmal dilatation of a persistent ductus arteriosus Botalli: a rare syndrome
Authors: Lindberg Knut , Brunvand Leif
Published: July 2005

A child with congenital mydriasis and aneurismal dilatation of persistent ductus arteriosus is described. We discuss congenital mydriasis as a separate entity and in combination with heart diseases.
Engineering craniofacial scaffolds
Authors: Hollister SJ , Lin CY , Saito E , Lin CY , Schek RD , Taboas JM , Williams JM , Partee B , Flanagan CL , Diggs A , Wilke EN , Van Lenthe GH , Müller R , Wirtz T , Das S , Feinberg SE , Krebsbach PH
Published: July 2005

Structured Abstract:

Authors –  Hollister SJ, Lin CY, Saito E, Lin CY, Schek RD, Taboas JM, Williams JM, Partee B, Flanagan CL, Diggs A, Wilke EN, Van Lenthe GH, Müller R, Wirtz T, Das S, Feinberg SE, Krebsbach PH

Objective –  To develop an integrated approach for engineering craniofacial scaffolds and to demonstrate that these engineered scaffolds would have mechanical properties in the range of craniofacial tissue and support bone regeneration for craniofacial reconstruction.

Experimental Variable –  Scaffold architecture designed to achieve desired elasticity and permeability. Scaffold external shape designed to match craniofacial anatomy.

Outcome Measure –  Final fabricated biomaterial scaffolds. Compressive mechanical modulus and strength. Bone regeneration as measured by micro‐CT scanning, mechanical testing and histology.

Setting –  Departments of Biomedical Engineering, Oral/Maxillofacial Surgery, and Oral Medicine, Pathology and Oncology at the University of Michigan.

Results –  Results showed that the design/fabrication approach could create scaffolds with designed porous architecture to match craniofacial anatomy. These scaffolds could be fabricated from a wide range of biomaterials, including titanium, degradable polymers, and degradable calcium phosphate ceramics. Mechanical tests showed that fabricated scaffolds had compressive modulus ranging 50 to 2900 MPa and compressive strength ranging from 2 to over 56 MPa, within the range of human craniofacial trabecular bone. In vivo testing of designed scaffolds showed that they could support bone regeneration via delivery of BMP‐7 transduced human gingival fibroblasts in a mouse model. Designed hydroxyapatite scaffolds with pore diameters ranging from 400 to 1200 microns were implanted in minipig mandibular defects for 6 and 18 weeks. Results showed substantial bone ingrowth (between 40 and 50% at 6 weeks, between 70 and 80% at 18 weeks) for all scaffolds, with no significant difference based on pore diameter.

Conclusion –  Integrated image‐based design and solid free‐form fabrication can create scaffolds that attain desired elasticity and permeability while fitting any 3D craniofacial defect. The scaffolds could be manufactured from degradable polymers, calcium phosphate ceramics and titanium. The designed scaffolds supported significant bone regeneration for all pore sizes ranging from 300 to 1200 microns. These results suggest that designed scaffolds are clinically applicable for complex craniofacial reconstruction.
Enzymatically cross‐linked hydrogels and their adhesive strength to biosurfaces
Authors: Hu B‐H , Messersmith PB
Published: July 2005

Structured Abstract

Authors –  Hu B‐H, Messersmith PB

Objectives –  To design an in‐situ gelling hydrogel capable of solidifying rapidly under physiologic conditions into a hydrogel capable of adhering tissue surfaces together.

Design –  Multifunctional polymers containing covalently bound peptide substrates of transglutaminase were designed.

Experimental Variable –  Enzyme cross‐linked hydrogels were compared with commercial fibrin tissue adhesive.

Outcome Measure –  The shear strength between tissue surfaces or type 1 collagen membranes bonded with hydrogel was measured.

Results –  The shear adhesive strength of transglutaminase cross‐linked hydrogels was found to be equal to or better than fibrin sealant for tissue and collagen surfaces, respectively.

Conclusion –  Transglutaminase cross‐linked hydrogels are injectable, in‐situ formed, biodegradable, and expected to be useful in a variety of applications including sustained drug delivery, medical and dental adhesives, tissue repair and engineering as polymeric scaffolds, and gene therapy.
In vitro engineering of cartilage: effects of serum substitutes, TGF‐β, and IL‐1α
Authors: Glowacki J , Yates KE , MacLean R , Mizuno S
Published: July 2005

Structured Abstract

Authors –  Glowacki J, Yates KE, MacLean R, Mizuno S.

Objectives –  Cartilage is avascular and relatively homogeneous, making it an attractive tissue for in vitro histogenesis and surgical use in patients. We developed novel platform technologies in order to define the requirements for optimal in vitro chondrogenesis by isolated cells. In this series of studies, we tested alternatives to fetal bovine serum (FBS) and the effects of growth factors on formation of cartilage in 3D porous collagen sponges.

Design –  We used porous collagen sponges to assess the effects of serum substitutes and exogenous TGF‐β1 and IL‐1α on chondrocytes (bovine articular chondrocytes, bACs) and on chondroinduced human dermal fibroblasts (hDFs). We determined the effects of low concentrations of FBS and two serum substitutes, Nutridoma and ITS+3, on cellularity and matrix production. After culture for intervals, sponges were harvested for histological and biochemical measurement of cartilage‐specific chondroitin 4‐sulfate proteoglycan (C 4‐S PG).

Results –  Cultured bACs showed equivalent growth in Nutridoma (1%) and 10% FBS. Both TGF‐β1 and IL‐1α significantly stimulated accumulation of C 4‐S PG by bACs in 3D porous collagen sponges. Many endogenous growth factors were upregulated in hDFs cultured with chondroinductive DBP. Addition of TGF‐β1 and IL‐1α for 11 days significantly stimulated accumulation of C 4‐S PG by hDFs cultured in DMEM with 1% Nutridoma.

Conclusion –  Porous collagen sponges are supportive of chondrogenesis and of chondroinduction by DBP. Optimization of serum‐free culture conditions, including growth factors, matrix components, and mechanical stimuli will expedite translation to wider clinical applications. Use of autogenous dermal fibroblasts pre‐cultured with DBP and induced to chondrocytes offers an alternative to autogenous chondrocytes.
The management of skin reactions in cancer patients receiving epidermal growth factor receptor targeted therapies
Authors: Segaert Siegfried , Tabernero Josep , Chosidow Olivier , Dirschka Thomas , Elsner Joern , Mancini Luca , Maughan Tim , Morere Jean‐Franµois , Santoro Armando , Sobrero Alberto , Van Cutsem Eric , Layton Alison
Published: July 2005

The use of epidermal growth factor receptor (EGFR) inhibitors for the treatment of solid tumours is increasing. However, the tolerability profile for EGFR‐inhibitors, such as the monoclonal antibody cetuximab and the tyrosine kinase inhibitor erlotinib, is characterised by a unique group of skin reactions dominated by an acneiform eruption, xerosis, eczema and changes in the hair and nails. The possibility that this skin toxicity correlates with anti‐tumour activity offers the potential to titrate dosing on a case‐by‐case basis. These skin effects may constitute a significant obstacle to treatment compliance. Accordingly, there is a need for consistent, multi‐disciplinary management strategies that will allow patients to receive the recommended dosages of such targeted therapies. The eruption responds well to some acne therapies and xerosis can be controlled by standard emollients. Here we present an overview of the treatment options for skin reactions that are available today, and evaluate some of the ways in which the treatment of such EGFR‐inhibitor‐related skin reactions may be improved in the future. Evidence‐based studies are needed to determine the best way to manage these effects.
Klinefelter‐Syndrom mit Mischkollagenose (Sharp‐Syndrom) und postthrombotischem Syndrom bei Thrombophilie
Authors: Kasten Robert , Pfirrmann Gudrun , Voigtländer Volker
Published: July 2005

Bei einem 43jährigen Patienten mit einem auffallend gynäkoiden Habitus bestand seit 6 Jahren ein postthrombotisches Syndrom mit Ulcera cruris rechts. Der Verdacht auf ein Klinefelter‐Syndrom konnte zytogenetisch bestätigt werden (47, XXY). Das Thrombophiliescreening ergab einen Protein‐S‐Mangel, eine Hyperhomozysteinämie sowie ein positives Lupusantikoagulans. Zusätzlich assoziiert war eine Mischkollagenose (Sharp‐Syndrom) mit einer Akrosklerose, proximalen Fingerödemen, einem Raynaud‐Phänomen, hochtitrigen ANA und positiven U1‐RNP‐Antikörpern, außerdem eine Osteoporose. Es gibt Hinweise, daß Klinefelter‐Patienten aufgrund ihres Androgenmangels sowohl zu Kollagenosen als auch zu einer Thrombophilie neigen. Eine Testosteronsubstitution kann nicht nur eine assoziierte Autoimmunerkrankung, sondern auch die Thromboseneigung und eine Osteoporose günstig beeinflussen.