bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of defibrotide, a novel oligodeoxyribonucleotide, on ischaemia and reperfusion injury of the rat liver
Authors: Kim Kwang Joon , Shin Yong Kyoo , Song Jin Ho , Oh Byung Kwon , Choi Myung Sup , Sohn Uy Dong
Published: March 2003

1 The purpose of this study was to investigate the protective effects of defibrotide, a single‐stranded polydeoxyribonucleotide, on ischaemia–reperfusion injury to the liver using a rat model.

2 Ischaemia of the left and median lobes was created by total inflow occlusion for 30 min followed by 60 min of reperfusion. Hepatic injury was assessed by the release of liver enzymes (alanine transferase, ALT and lactic dehydrogenase, LDH). Hepatic oxidant stress was measured by superoxide production, lipid peroxidation and nitrite/nitrate formation. Leukocyte–endothelium interaction and Kupffer cell mobilization were quantified by measuring hepatic myeloperoxidase (MPO), polymorphonuclear leukocyte adherence to superior mesenteric artery (SMA) and immunostaining of Kupffer cell.

3 Defibrotide treatment resulted in a significant inhibition of postreperfusion superoxide generation, lipid peroxidation, serum ALT activity, serum LDH activity, MPO activity, serum nitrite/nitrate level, leukocyte adherence to SMA, and Kupffer cell mobilization, indicating a significant attenuation of hepatic dysfunction.

4 A significant correlation existed between liver ischaemia/reperfusion and hepatic injury, suggesting that liver ischaemia/reperfusion injury is mediated predominantly by generation of oxygen free radicals and mobilization of Kupffer cells.

5 We conclude that defibrotide significantly protects the liver against liver ischaemia/reperfusion injury by interfering with Kupffer cell mobilization and formation of oxygen free radicals. This study provides strong evidence that defibrotide has important beneficial effects on acute inflammatory tissue injury such as that occurring in the reperfusion of the ischaemic liver.
Effects of rutin and harmaline on rat reflux oesophagitis
Authors: Shin Y. K. , Sohn U. D. , Choi M. S. , Kum C. , Sim S. S. , Lee M. Y.
Published: March 2003

1 This study was aimed at evaluating the effect of rutin and harmaline (1‐methyl‐7‐methoxy‐3,4‐dihydro‐β‐carboline) on the development of the surgically induced reflux oesophagitis, on gastric secretion, lipid peroxidation, polymorphonucleocytes (PMNs) accumulation, superoxide and hydroxyl radical production in PMNs, cytokine [interleukin‐1β (IL‐1β), tumour necrosis factor‐α (TNF‐α)] production in blood and [Ca2+]i mobilization in PMNs.

2 Rutin and harmaline significantly prevented the development of reflux oesophagitis and gastric secretion. Treatments of oesophagitis rats with rutin and harmaline inhibited lipid peroxidation, and myeloperoxidase (MPO) in the oesophagus in comparison with untreated rats.

3 Superoxide anion and hydrogen peroxide production in 1 μm formylmethionylleucylphenylalanine (fMLP)‐ or 0.1 μg ml−1N‐phorbol 12‐myristate 13‐acetate (PMA)‐activated PMNs was inhibited by rutin and harmaline in a dose‐dependent fashion. Rutin and harmaline effectively scavenged the hydroxyl radical and hydrogen peroxide. Treatments of oesophagitis rats with rutin and harmaline inhibited IL‐1β production in the oesophagus in comparison with untreated rats, but TNF‐α production was not affected by rutin and harmaline. The fMLP‐induced elevation of [Ca2+]i was inhibited by rutin.

4 The results of this study suggest that rutin and harmaline may have beneficial protective effects against reflux oesophagitis by the inhibition of gastric acid secretion, oxidative stress, inflammatory cytokine production (i.e. IL‐1β), and intracellular calcium mobilization in PMNs in rats.
Induction of duodenal motility activates the sphincter of Oddi (SO)‐duodenal reflex in the Australian possum in vitro
Authors: Konomi H. , Simula M. E. , Meedeniya A. C. B. , Toouli J. , Saccone G. T. P.
Published: March 2003

1 The aim of this study was to determine if stimulation of duodenal motility by duodenal fluid distension or by administration of carbachol, activates the sphincter of Oddi‐duodenal reflex, in an in vitro preparation from the Australian possum.

2 Duodenal distension was achieved by infusion of Krebs solution (0–8 cm H2O). In separate experiments, the sphincter of Oddi (SO) was partitioned from the duodenum and carbachol (10−7−5 × 10−6 m) added to the duodenal compartment.

3 Fluid distension increased duodenal motility to 120–600% of control activity. These treatments induced increased SO motility (to 120–390% of control) in six preparations, reduced activity (to 60% of control) in one and no response in another.

4 Addition of carbachol to the duodenal compartment resulted in increased duodenal motility. SO motility was increased in seven preparations, reduced in another two and no response were evoked in two others. All SO responses were blocked by tetrodotoxin pretreatment.

5 These data suggest that the SO receives inputs from duodenal mechano and/or stretch receptors resulting in excitatory or inhibitory responses, with the excitatory response dominating. These findings support the role for the SO‐duodenal reflex in preventing duodeno‐biliary/pancreatic reflux during periods of elevated duodenal activity.
Functional importance of the actin cytoskeleton in contraction of bovine iris sphincter muscle
Authors: Filipe J. A. C. , Nunes J. P. L.
Published: March 2003

1 The contractile capacity of smooth muscle cells depends on the cytoskeletal framework of the cell. The aim of this study was to determine the functional importance of both the actin and the tubulin components of the cytoskeleton in contractile responses of the bovine isolated iris sphincter muscle.

2 In each preparation, two contractions to the muscarinic agonist carbachol were obtained. The maximum responses of the first contractions were taken as 100%. The second contractions to carbachol were elicited in the presence of either cytochalasin B (50 and 5 μm), an inhibitor of the actin cytoskeleton, or colchicine (100 μm), an inhibitor of the tubulin cytoskeleton (30 min incubation).

3 Cytochalasin B, at a concentration of 50 μm, significantly decreased the contractions induced by carbachol, with the maximum response reduced to 21.8 ± 6.6% (n = 12) of the initial maximum. The maximal contractions to carbachol in the presence of colchicine reached 96.2 ± 7.9% (n = 9) of the initial contraction, which was not significantly different from control second responses to carbachol with neither drug present, which reached 113.3 ± 7.6% (n = 7).

4 The effect of cytochalasin B was dose‐dependent, since at a lower concentration of 5 μm, the drug decreased the maximum contraction to carbachol to 60.3 ± 8.8% (n = 6). The effect of cytochalasin B was at least partially reversible, since after the use of the higher concentration of 50 μm, contractions to carbachol increased to 62.3 ± 15.5% (n = 4) of the maximal response, after 1 h repeated washing of the preparations.

5 Cytochalasin D, at a concentration of 50 μm, completely abolished the contractions induced by carbachol (n = 4).

6 These findings suggest that in bovine iris sphincter muscle, contractions to carbachol are highly dependent, from a functional point of view, on actin polymerization, and not, to any important degree, on the polymerization of tubulin.
Studies on the mechanism of enhancement of purinergic transmission by caffeine in the guinea‐pig isolated vas deferens
Authors: Ziogas J. , O'Farrell M.
Published: March 2003

1 Purinergic transmission from sympathetic nerves in the guinea‐pig vas deferens was monitored using intracellular recording techniques. Stimulation of the hypogastric nerve with trains of 15 pulses at 1 Hz evoked excitatory junction potentials (EJPs) which increased in amplitude from the first pulse and reached a maximum after 6–8 pulses.

2 Caffeine (3 and 10 mm), depolarized cells by 5–10 mV and increased the amplitude of the first few EJPs in each train but reduced the maximum amplitude of EJPs late in the train.

3 The adenosine receptor antagonist 8‐p‐sulphophenyl‐theophylline (8‐SPT; 30 μm) had no effect on either the resting membrane potential or the EJP amplitude; however, at 100 μm it reduced the amplitude of all EJPs by 5–10%.

4 Adenosine (10 and 30 μm) reduced the amplitude of EJPs in a concentration‐dependent manner. The inhibitory effect of adenosine on EJP amplitude was prevented by pretreatment with either caffeine (3 mm) or 8‐SPT (30 μm).

5 Ryanodine (30 μm) did not alter EJP amplitude and did not inhibit the enhancement of the first EJP by caffeine (3 mm). Incubation of the tissue with the cell permeable calcium chelator 1‐2‐bis(o‐aminophenoxy)ethane‐N,N‐N′,N′‐tetraacetic acid (BAPT‐AM) resulted in a depression of EJP amplitude and a longer time to reach maximum amplitude. In cells that had been exposed to BAPT‐AM, caffeine 3 mm still increased amplitude of EJP early in the train.

6 The phosphodiesterase inhibitor, 3‐isobutyl‐1‐methylxanthine (IBMX; 500 μm), hyperpolarized cells and increased the amplitude of EJP throughout the train of stimulation. In the presence of IBMX, caffeine 3 mm still depolarized the cells and enhanced the EJP early in the train of stimulation.

7 The findings in this study confirm that caffeine and 8‐SPT are effective inhibitors of the actions of adenosine. However, caffeine has an additional action to enhance EJP early during a train of stimulation, which cannot be attributed to blockade of adenosine receptors, but which may be related to inhibition of phosphodiesterase.
Modulatory effect of the adrenergic system upon fibroblast proliferation: participation of β3‐adrenoceptors
Authors: Anesini C. , Borda E.
Published: March 2003

1 The β3‐adrenoceptor agonist ZD 7114, like the non‐selective β‐adrenoceptor agonist isoprenaline, but unlike the β1‐adrenoceptor agonist dobutamine and the β2‐adrenoceptor agonist salbutamol, produced an increment on mouse embryonic fibroblast proliferation. The half‐maximal stimulation of cell growth occurred at substantially lower concentrations with the β3‐adrenoceptor agonist (EC50: 5.5 × 10−8 m) than with isoprenaline (EC50: 1.25 × 10−6 m).

2 The selective β3‐adrenoceptor antagonist SR 5923 OA prevented the β3‐stimulated fibroblast proliferation. Conversely, practolol and butoxamine did not prevent fibroblast growth.

3 Additionally, a decrease of cAMP was obtained in fibroblasts cells upon stimulation with isoprenaline and ZD 7114.

4 The expression of β‐adrenoreceptors on fibroblast cells was also studied by radioligand binding. The Ki values in the presence of β1‐ and β2‐adrenoceptor antagonist was two‐fold higher than the Ki values for β3 adrenoceptor antagonist indicating the presence of A3‐receptor subtype.

5 Inhibitors of different intracellular coupling pathways including phospholipase C (U 73122), protein kinase C (staurosporine), calcium/calmodulin (trifluoroperazine) and calcium channel (verapamil), prevented the stimulatory actions of the selective β3‐adrenoceptor agonist ZD 7114.

6 The presence of β3‐adrenoceptors on embryonic mouse fibroblast cells may play a role in the modulation of cell growth and biologic activity. The mechanism by which ZD 7114 triggers cell proliferation and function, involves the activation of phospholipase C, PKC, calcium/calmodulin and the influx of calcium.
Involvement of κ‐opioid receptors in peripheral response to nerve stimulation in κ‐opioid receptor knockout mice
Authors: Mitolo‐Chieppa D. , Natale L. , Marasciulo F. L. , De Salvatore G. , Mitolo C. I. , Siro‐Brigiani G. , Renna G. , De Salvia M. A.
Published: March 2003

1 The present study aimed to evaluate the role of κ‐opioid receptors at two peripheral sites, the vas deferens and the proximal colon, in κ‐opioid receptor knockout mice. We investigated the role of the κ‐opioid receptor in the vas deferens twitch response and in the colonic ‘off‐contraction’, a rebound contractile response which follows the inhibitory response to low frequencies stimulation (10, 20, 30 Hz) and which has been suggested to ‘locally’ reproduce the contractile component of the peristaltic reflex.

2 Transmural stimulation of the vas deferens at lower frequencies (10 Hz, 10 V, 1 ms pulse trains lasting 0.5 s) evoked a contractile response that was significantly higher in the preparations from knockout mice because of lack of κ‐opioid receptors than in wild type mice. A selective κ‐opioid receptor agonist, U‐50,488H, induced a dose‐dependent inhibition of the electrically stimulated contraction in vas deferens. The percentages of reduction of the twitch response were significantly lower in knockout mice than in wild type mice after treatment with U‐50,488H. The reduction of twitch response caused by U‐50,488H was not reversed by administration of nor‐binaltorphimine (nor‐BNI) (5 × 10−6 m), a selective κ‐opioid receptor antagonist, in preparations from both knockout mice and wild type mice. U‐50,488H has no effect on postsynaptic adrenergic receptors, as its administration did not affect the direct contractile response to noradrenaline.

3 Transmural stimulation (5 Hz, 20 V, 2 ms pulse trains lasting 30 s) induced inhibition of spontaneous activity of colonic strips during the period of stimulation, followed by an ‘off‐contraction’ after the cessation of stimulation. The statistical evaluation of the ‘off‐contraction’ responses between the two strains showed no significant difference. The off‐contraction, measured in specimens from knockout mice, was inhibited concentration‐dependently by U‐50,488H (P < 0.01) and significantly less than from wild type mice.

4 The effect of U‐50,488H was not reversed by administration of nor‐BNI (5 × 10−6 m), either in preparations from knockout mice or from wild type mice.

5 Our data may suggest that κ‐opioid receptors are involved in some peripheral responses to the nerve stimulation, as indicated by the effect of U‐50,488H, a selective κ‐opioid receptor agonist. However, the involvement of κ‐opioid receptor was also present, although less apparent, in κ ‐opioid receptor knockout mice, suggesting either that this drug acts not only on κ‐opioid receptors but also on other receptor sites, such as κ‐like receptors. An alternative interpretation can be related to a sodium channel blocking action of U‐50,488H, which could explain the inhibitory effects of twitch response still present but less evident in knockout strain and the lack of effect of the antagonist nor‐BNI.
Comparison of catecholamine release in the isolated adrenal glands of SHR and WKY rats
Authors: Lim D.‐Y. , Jang S.‐J. , Park D.‐G.
Published: March 2003

1 The present study was designed to investigate the secretion of catecholamines (CA) evoked by stimulation of cholinergic receptors and membrane depolarization from the isolated perfused adrenal gland of spontaneously hypertensive rats (SHR) and normotensive Wistar–Kyoto rats (WKYR) at adult age.

2 The wet weight of adrenal gland in SHR was greater than that in WKYR. The CA releasing responses evoked by acetylcholine (5.32 × 10−3 m), and high potassium (5.6 × 10−2 m), a membrane depolarizer, were significantly lower in WKYR than in SHR.

3 The secretory responses of CA evoked by DMPP (10−4 m for 2 min), a selective agonist of neuronal nicotinic receptors, and McN‐A‐343 (10−4 m for 2 min), a selective agonist of neuronal muscarinic receptors, were also significantly lower in WKYR than in SHR.

4 The CA release evoked by Bay‐K‐8644 (10−5 m), a dihydropyridine‐sensitive Ca2+ channel activator, and cyclopiazonic acid (10−5 m), a selective inhibitor of Ca2+‐ATPase in the endoplasmic reticulum, were also significantly greater in SHR than WKYR.

5 Taken together, these experimental results demonstrate that the CA secretion evoked by stimulation of cholinergic (nicotinic and muscarinic) receptors as well as membrane depolarization is enhanced more greatly in the perfused adrenal glands of SHR than in those of WKYR. It is suggested that the augmented CA release in SHR compared with WKYR was involved in essential hypertensive pathogenesis.
Ironing out Parkinson's disease: is therapeutic treatment with iron chelators a real possibility?
Authors: Kaur Deepinder , Andersen Julie K.
Published: March 2003

Levels of iron are increased in the brains of Parkinson's disease (PD) patients compared to age‐matched controls. This has been postulated to contribute to progression of the disease via several mechanisms including exacerbation of oxidative stress, initiation of inflammatory responses and triggering of Lewy body formation. In this minireview, we examine the putative role of iron in PD and its pharmacological chelation as a prospective therapeutic for the disease.
Asymmetry of DNA replication fork progression in Werner's syndrome
Authors: Rodríguez‐López Ana M. , Jackson Dean A. , Iborra Francisco , Cox Lynne S.
Published: March 2003

Human aging is associated with accumulation of cells that have undergone replicative senescence. The rare premature aging Werner's syndrome (WS) provides a phenocopy of normal human aging and WS patient cells recapitulate the aging phenotype in culture as they rapidly lose the ability to proliferate or replicate their DNA. WS is associated with loss of functional WRN protein. Although the biochemical properties of WRN protein, which possesses both helicase and exonuclease activities, suggest an involvement in DNA metabolism, its action in cells is not clear. Here, we provide experimental evidence for a role of the WRN protein in DNA replication in normally proliferating cells. Most importantly, we demonstrate that in the absence of functional WRN protein, replication forks from origins of bidirectional replication fail to progress normally, resulting in marked asymmetry of bidirectional forks. We propose that WRN acts in normal DNA replication to prevent collapse of replication forks or to resolve DNA junctions at stalled replication forks, and that loss of this capacity may be a contributory factor in premature aging.
Interpreting interactions between treatments that slow aging
Authors: Gems David , Pletcher Scott , Partridge Linda
Published: March 2003

A major challenge in current research into aging using model organisms is to establish whether different treatments resulting in slowed aging involve common or distinct mechanisms. Such treatments include gene mutation, dietary restriction (DR), and manipulation of reproduction, gonadal signals and temperature. The principal method used to determine whether these treatments act through common mechanisms is to compare the magnitude of the effect on aging of each treatment separately with that when two are applied simultaneously. In this discussion we identify five types of methodological shortcomings that have marred such studies. These are (1) submaximal lifespan‐extension by individual treatments, e.g. as a result of the use of hypomorphic rather than null alleles; (2) effects of a single treatment on survival through more than one mechanism, e.g. pleiotropic effects of lifespan mutants; (3) the difficulty of interpreting the magnitude of increases in lifespan in double treatments, and failure to measure and model age‐specific mortality rates; (4) the non‐specific effects of life extension suppressors; and (5) the possible occurrence of artefactual mutant interactions. When considered in the light of these problems, the conclusions of a number of recent lifespan interaction studies appear questionable. We suggest six rules for avoiding the pitfalls that can beset interaction studies.
Pre‐mRNA splicing modulations in senescence
Authors: Meshorer Eran , Soreq Hermona
Published: March 2003

Aging and associated diseases involve multilevel changes in the complex phenomenon of alternative splicing. Here, we review the potential genomic and environmental origins of such changes and discuss the research implications of these findings.
Big mice die young: early life body weight predicts longevity in genetically heterogeneous mice
Authors: Miller Richard A. , Harper James M. , Galecki Andrzej , Burke David T.
Published: March 2003

Small body size has been associated with long life span in four stocks of mutant dwarf mice, and in two varieties of dietary restriction in rodents. In this study, small body size at ages 2–24 months was shown to be a significant predictor of life span in a genetically heterogeneous mouse population derived from four common inbred mouse strains. The association was strongest for weights measured early in adult life, and somewhat weaker, though still statistically significant, at later ages. The effect was seen both in males and females, and was replicated in an independent population of the same genetic background. Body size at ages 2–4 months was correlated with levels of serum leptin in both males and females, and with levels of IGF‐I and thyroid hormone in females only. A genome scan showed the presence of polymorphic alleles on chromosomes 2, 6, 7 and 15 with significant effects on body weight at 2–4 months, at 10–12 months, or at both age ranges, showing that weight gain trajectory in this stock is under complex genetic control. Because it provides the earliest known predictor of life span, body weight may be usefully included in screens for induced mutations that alter aging. The evidence that weight in 2‐month‐old mice is a significant predictor of life span suggests that at least some of the lethal diseases of old age can be timed by factors that influence growth rate in juvenile rodents.
Oxidative stress and aging: beyond correlation
Authors: Golden Tamara R. , Hinerfeld Douglas A. , Melov Simon
Published: March 2003

The oxidative stress theory of aging has become increasingly accepted as playing a role in the aging process, based primarily on a substantial accumulation of circumstantial evidence. In recent years, the hypothesis that mitochondrially generated reactive oxygen species play a role in organismal aging has been directly tested in both invertebrate and mammalian model systems. Initial results imply that oxidative damage, specifically the level of superoxide, does play a role in limiting the lifespans of invertebrates such as Drosophila melanogaster and Caenorhabditis elegans. In mammalian model systems, the effect of oxidative stress on lifespan is less clear, but there is evidence that antioxidant treatment protects against age‐related dysfunction, including cognitive decline.
Regenerative potential of human skeletal muscle during aging
Authors: Renault Valérie , Thorne Lars‐Eric , Eriksson Per‐Olof , Butler‐Browne Gillian , Mouly Vincent
Published: March 2003

In this study, we have investigated the consequences of aging on the regenerative capacity of human skeletal muscle by evaluating two parameters: (i) variation in telomere length which was used to evaluate the in vivo turn‐over and (ii) the proportion of satellite cells calculated as compared to the total number of nuclei in a muscle fibre. Two skeletal muscles which have different types of innervation were analysed: the biceps brachii, a limb muscle, and the masseter, a masticatory muscle. The biopsies were obtained from two groups: young adults (23 ± 1.15 years old) and aged adults (74 ± 4.25 years old). Our results showed that during adult life, minimum telomere lengths and mean telomere lengths remained stable in the two muscles. The mean number of myonuclei per fibre was lower in the biceps brachii than in the masseter but no significant change was observed in either muscle with increasing age. However, the number of satellite cells, expressed as a proportion of myonuclei, decreased with age in both muscles. Therefore, normal aging of skeletal muscle in vivo is reflected by the number of satellite cells available for regeneration, but not by the mean number of myonuclei per fibre or by telomere lengths. We conclude that a decrease in regenerative capacity with age may be partially explained by a reduced availability of satellite cells.
Life history, ecology and longevity in bats
Authors: Wilkinson Gerald S. , South Jason M.
Published: March 2003

The evolutionary theory of aging predicts that life span should decrease in response to the amount of mortality caused by extrinsic sources. Using this prediction, we selected six life history and ecological factors to use in a comparative analysis of longevity among 64 bat species. On average, the maximum recorded life span of a bat is 3.5 times greater than a non‐flying placental mammal of similar size. Records of individuals surviving more than 30 years in the wild now exist for five species. Univariate and multivariate analyses of species data, as well as of phylogenetically independent contrasts obtained using a supertree of Chiroptera, reveal that bat life span significantly increases with hibernation, body mass and occasional cave use, but decreases with reproductive rate and is not influenced by diet, colony size or the source of the record. These results are largely consistent with extrinsic mortality risk acting as a determinant of bat longevity. Nevertheless, the strong association between life span and both reproductive rate and hibernation also suggests that bat longevity is strongly influenced by seasonal allocation of non‐renewable resources to reproduction. We speculate that hibernation may provide a natural example of caloric restriction, which is known to increase longevity in other mammals.
Differential regulation of Shc adaptor proteins in skeletal muscle, spinal cord and forebrain of aged rats with sensorimotor impairment
Authors: Jiang Xiaogang , Edstrom Erik , Altun Mikael , Ulfhake Brun
Published: March 2003

The Shc family of proteins participates in mitogenic and survival signalling through binding to receptor tyrosine kinases. We report here on the expression of Shc in forebrain, spinal cord and hind limb muscles from 30‐month‐old rats with different degrees of sensorimotor impairment. ShcA (mRNA and protein) is up‐regulated in skeletal muscles and spinal cord of aged rats, and this change relates to biological age, i.e. degree of behavioural incapacitation, rather than to chronological age. Western blot and RT‐PCR revealed that the increase in ShcA selectively affected the p46 isoform in the spinal cord, whereas in muscle tissue a robust increase of p66ShcA was also evident. Furthermore, in parallel with the up‐regulation of ShcA, an increase of p75NTR mRNA in the aged animals was observed. ShcB mRNA showed a tendency for down‐regulation in both spinal cord and skeletal muscles, whereas the expression of ShcC was unaltered. Our data show that the regulation of Shc mRNAs in senescence is region as well as isoform specific. The regulatory changes may reflect changes in mitogenic/survival signalling induced by age‐related cell and tissue damage. The coup‐regulation of p66ShcA and p75NTR is interesting since both molecules have been associated with apoptosis.
Apoptosis, necrosis and cellular senescence: chaperone occupancy as a potential switch
Authors: Sõti Csaba , Sreedhar Amere Subbarao , Csermely Péter
Published: March 2003

Chaperone function plays a key role in repairing proteotoxic damage and in the maintenance of cell survival. Here we compare the regulatory role of molecular chaperones (heat shock proteins, stress proteins) in cellular senescence, apoptosis and necrosis. We also review the current data on chaperone level and function in aging cells, and list some possible therapeutic interventions. Finally, we postulate a hypothesis, that increasing chaperone occupancy might be an important event which forces cells out of the normal cell cycle towards senescence. In the case of severe stress, this may lead to apoptosis or, following lethal stress, to cell necrosis.
Experiences of Emergency Cesarean Section: A Phenomenological Study of 53 Women
Authors: Ryding Elsa Lena , Wijma Klaas , Wijma Barbro ,   Elsa Lena Ryding is a consultant at the Department of Obstetrics and Gynaecology, Central Hospital, Helsingborg, Sweden. Klaas Wijma is a clinical psychologist and associate professor, and Barbro Wijma is a senior consultant and an associate professor, both at the Department of Obstetrics and Gynaecology, University Hospital, Linköping, Sweden.
Published: March 2003

Background:
Childbirth by emergency cesarean section can be a traumatic experience, but since the result is often a healthy mother and baby, its seriousness is open to doubt.
Method:
Fifty‐three women were interviewed approximately two days after emergency cesarean section to ascertain whether or not the trauma met the stressor criterion of posttraumatic stress disorder. A time‐spatial model from disaster psychiatry was used to chart the women's thoughts and feelings during consecutive phases of the delivery process. The women's causal attributions of the event were also assessed.
Results:
Generally speaking, the feeling of the women after they had arrived at the delivery ward changed from one of confidence and safety to one of fear. The decision to undertake a cesarean section brought a feeling of relief, but this was again replaced by fear as the operation approached. The women's thoughts centered around the impending delivery and operation until after the event, when the newborn baby occupied their attention and happiness predominated. In retrospect, 55 percent of the women experienced intense fear for their own life or that of their baby. Eight percent felt very badly treated by the delivery staff and were angry. Almost all the women had adequate knowledge of the reasons for the emergency cesarean section. One in four blamed themselves to some extent for the event.
Conclusions:
The stressor criterion of DSM IV is applicable to the trauma of emergency cesarean section. Even if and when a new mother is happy to meet her baby, negative feelings, such as fear, guilt, or anger, may dominate her memories of the birth. (BIRTH 25:4 December 1998)
Subprojekt 3.8. des Kompetenznetzes „Depression/Suizidalität" im Teilprojekt 3 „Qualitätsmanagement in der Depressionsbehandlung"
Authors: Dragicevic A. , Fric M. , Geiger E. , Grasmäder K. , Härtter S. , Kuss H.-J. , Laux G. , Lohmann P.L. , Mletzko W. , Müller M.J. , Rao M.L. , Schanz B. , Scherer A. , Hiemke C.
Published: March 2003

Therapeutisches Drug Monitoring (TDM) ist bei Verordnung eines Antidepressivums eine potenziell nützliche Therapieergänzung. Wenn TDM unter naturalistischen Bedingungen für trizyklische Antidepressiva eingesetzt wurde, waren die Blutspiegel depressiver Patienten mit TDM häufiger auf therapeutische Konzentrationen eingestellt als ohne TDM. Mit der Einstellung therapeutischer Blutspiegel war die Wahrscheinlichkeit, auf die Therapie anzusprechen um das 2,3fache erhöht, Nebenwirkungen waren seltener. Erste Berichte der Literatur belegen, dass sich das Therapieansprechen bei der Behandlung depressiver Patienten mit selektiven Serotoninwiederaufnahmehemmer ebenfalls durch eine TDM-geleitete Dosisanpassung verbessern lässt. Dadurch sind Einsparungen in den Behandlungskosten möglich. Es gibt daher zunehmende Evidenz, dass TDM die Effizienz und Sicherheit einer antidepressiven Therapie bei einer Behandlung mit alten oder neuen Antidepressiva verbessern kann.
A new form for the third−order asymptotic aberration coefficients of electrostatic lenses; application to the two−tube electrostatic lens
Authors: DiChio D. , Natali S. V. , Kuyatt C. E.
Published: March 2003

The third−order asymptotic aberration coefficients of round electrostatic lenses are reformulated in terms of the coordinates formed by the projections of the asymptotic incident and final rays onto the reference plane of the lens. In this formulation, all aberration coefficients are finite for all lenses, in contrast to the formulation in terms of coordinates projected onto the focal planes of the lenses, where all of the coefficients become infinite in the limit of very weak lenses and for certain strong lenses. Equations for the six third−order aberration coefficients are derived in the form of integrals involving derivatives of the axial potential no higher than the second. Using these equations and previously calculated potentials and first−order trajectories, we have computed the six aberration coefficients for the accelerating and decelerating two−tube electrostatic lens for voltage ratios from 1.1 to 10000. The results are believed accurate to better than 0.2%.
XY table and tilting stage for scanning electron microscope (SEM)
Authors: Wells Oliver C.
Published: March 2003

This paper describes a low−vibration specimen stage in which the specimen is held by a block which slides on Teflon pads over the lower surface of the SEM lens. It provides X, Y, and tilting motions.
Further improvements in vibrating sample magnetometer sensitivity
Authors: Foner S.
Published: March 2003

Improvements in sensitivity of a vibrating sample magnetometer (VSM) are presented. General geometric scaling factors for VSM detection coils also are discussed. The scaling factors show why such increased sensitivity is achieved. For small detection coils and efficient coupling with the sample, noise levels correspond to a change in magnetic moment of 3×10−9 emu at 50 kOe and 1×10−9 emu at 10 kOe. This corresponds to a change in susceptibility Δχ?10−13 emu/g-Oe for a 1-g sample at 10 kOe.
Calibration studies of the carbon piezoresistive gauge
Authors: Horning R. R. , Isbell W. M.
Published: March 2003

The calibrations, time responses, and Hugoniot for carbon piezoresistive gauges from two manufacturers are presented. These gauges exhibit a high sensitivity of about −20% resistance change per GPa at 0.5 GPa. Their equilibration times, when tested in fused silica, exceed 0.6 μsec below 0.5 GPa but improve at higher stresses and under better impedance matching conditions. They can be made of low atomic number materials, making them interesting candidates for studying the mechanical responses of materials to electron and x-ray deposition.
Large, quiescent, magnetized plasma for wave studies
Authors: Gekelman W. , Stenzel R. L.
Published: March 2003

The development of a large magnetized plasma source for wave propagation experiments is described. The method employs a dc discharge in a weak magnetic field region and subsequent particle diffusion into a strong, uniform B-field region. The resultant steady-state plasma is uniform (8 cm⊥B0, 120 cm∥B0), quiescent (δn/n≲1%), has high density (ne≳1011 cm−3), a B0=1 kG, argon (3×10−4 Torr), and low collision rates (νen≃105 sec−1). The source can be easily scaled to larger dimensions. Plasma diagnostics with probes, microwaves, and spectroscopy for steady state and afterglow are described. Examples of wave propagation for ion acoustic waves, electron Bernstein waves, and lower hybrid waves indicate the versatility of the device.
Low impedance intense electron beam device
Authors: Myers B. , Eylon S. , Lieberman M. A.
Published: March 2003

A low cost, intense electron beam generating device is described. The device produces a 125 keV, 20 kA, 40 nsec beam (ν/γ ? 1.8). Commercially available coaxial cables are used in the Blumlein pulse forming network. Multiple gap switching is employed, and very low (∼2 nsec) jitter between gap firings is achieved by electrical isolation of adjacent gaps. A remotely changeable anode allows a 1 pulse/min repetition frequency.
Device for the determination of biaxial-symmetrical residual stresses in metallic, disk-shaped specimens
Authors: Bulckaen V. , Gucci N.
Published: March 2003

A device is described for the determination of the residual stresses in metallic disks up to 3 mm thickness due to axi-symmetric surface treatments on both faces. The apparatus is designed to measure normal stresses at any point on planes orthogonal to the disk in the cases, normally occurring in practice, of compressive internal stresses on carburized, nitrided, chromed, peened, etc., surfaces. The method consists of the electrochemical thinning of the disk, making the sample act as a rotating anode in a special electrolytic cell with floating cathode. During the operation, the spontaneous deformations of the disk are carefully compensated for by use of an annular bending load which guarantees a sufficient planarity of the outer surface of the disk. The electrolytic cell develops a plane attack front only on the internal surface; parallelism between the two faces is assured by accurate mechanical seating. The determination of the stress field is carried out by relating the bending of the disk, or the values of the counter-bending load applied to compensate for this bending with the unknown internal stresses. Two analytical treatments are thus developed, each of which is able to provide a measure of the internal stresses starting from experimental data which are different, but which are obtained in the course of the same test and are able to provide a check.
Ultrahigh pressure apparatus using cemented tungsten carbide pistons with sintered diamond tips
Authors: Bundy F. P.
Published: March 2003

A Drickamer-type apparatus has been made in which the highly-stressed tip regions of the Carboloy pistons are of dense sintered diamond. Experiments indicate that this apparatus is capable of attaining static pressures of over 400 kilobar on a newly revised scale. The results show that the 1970 revised pressure scale of Drickamer needs further revision downwards for the range above about 150 kilobar. A pressure scale based on electric resistance transitions up to 400 kilobar is proposed. Resistance vs press force curves are shown for Bi, Fe20Co, Fe40Co, CdS, GaP, BP, NaCl, and graphite.
High pressure generation by MASS 3I8−90 type apparatus
Authors: Masaki Kazuaki , Sawamoto Hiroshi , Ohtani Eiji , Kumazawa Mineo , Machida Michihide , Mizukusa Shin , Nakayama Noboru
Published: March 2003

MASS 3I8−90 type apparatus is developed to generate pressures up to 500 kilobar in a volume of 7.5 mm3. The geometry, operational mechanism, and the result of the pressure−generating experiment are described in detail.
A high−voltage telefocus electron gun with remote focusing
Authors: Schmoranzer H. , Wellenstein H. F. , Bonham R. A.
Published: March 2003

A new design for a telefocus electron gun is presented. Features include a nearly constant minimum FWHM of 180 μ with beam currents of 1−400 μA at focal distances from 1/2 to 1 1/2 m. The gun is especially designed to operate under adverse vacuum conditions with background pressures as high as 10−4 Torr with accelerating potentials of 10 to 60 keV. In addition tn can be remotely focused and positioned from outside the vacuum chamber in which the gun is used.
An open sample holder for electrical measurements between 0.1 and 6.0 GHz
Authors: Addison J. R.
Published: March 2003

A sample holder for either transmission or reflection measurements is described. Basically a length of five−wire or ’’cage’’ transmission line, when terminated with a 50 Ω load it exhibits (in air) a residual VSWR of less than 1.05 below 2.0 GHz and (with one exception) less than 1.08 up to 6.0 GHz. Designed for use with solid samples, it may be adapted to powders or fluids.
Toward optimum utilization of the cylindrical mirror analyzer in Auger electron spectroscopy
Authors: Pocker D. J.
Published: March 2003

Because of the essentially constant percentange resolution and transmission characteristics of electrostatic deflection−type electron energy analyzers, their use in potential modulation−type spectroscopies (such as Auger electron spectroscopy) is problematic, in that it is essentially impossible to choose a potential modulation amplitude capable of yielding anywhere near optimum resolution and/or sensitivity all the way across any wide energy range spectrum. A simple circuit for alleviating this problem is presented and demonstrated.
Superconducting stepping motors for use at millikelvin temperatures
Authors: Edwards D. O. , Kindler R. L. , Shen S. Y.
Published: March 2003

We describe simple superconducting stepping motors capable of rotating apparatus at dilution refrigerator temperatures. The heat produced by friction in a motor and its 10:1 reduction gearing is 6 ergs per step of 3°.
Cut−off waveguide refractometer
Authors: Kelly Arnold J.
Published: March 2003

A theory of waveguide behavior near cut−off as applied to the measurement of refractivity is developed. It is shown that the cut−off condition provides a means by which small changes [0(10−6)] in refractivity can be accurately measured. The general operating characteristics of a laboratory instrument operating at microwave frequencies (X−band) and designed for the measurement of atmospheric refractivity is presented.
An x−ray spectrometer for laser−induced plasmas
Authors: Cuderman J. F. , Glibert K. M.
Published: March 2003

A seven−channel K−edge filter spectrometer which uses Si PIN−type diodes has been developed as an x−ray diagnostic tool for laser plasma experiments. The spectrometer is designed to sample the photon energy range from 500 eV to 20 keV. The theory and techniques involved in the application of a K−edge filter−Si diode spectrometer to laser plasma studies are presented. Electron temperatures in plasmas are often determined by the two−foil ratio method. The present work defines conditions under which such a measurement may prove unreliable. Typical absolute x−ray spectra obtained from subnanosecond irradiation of 1000 μ CD2 spheres with a few joules of laser energy yields 200 eV electron temperatures and a 1% laser to x−ray conversion efficiency.
An instrument for the measurement of the mean square value of atmospheric star scintillation
Authors: Barletti R. , Paterno L.
Published: March 2003

A photoelectric instrument is described, giving directly in digital form the ratio of the mean square value of the current fluctuations (owing only to atmospheric star scintillation) and the square of the mean value of the current (owing to the star signal). This ratio is the measure of the atmospheric scintillation. The instrument was used for atmospheric optical quality measurements in connection with the European project JOSO (Joint Organization for Solar Observations).
Focusing of polar molecules in an electrostatic quadrupole: the use of a collimating orifice to remove the direct beam
Authors: Bromberg Edward E. A.
Published: March 2003

In electrostatic quadrupoles, which are used to focus state−selected beams of polar molecules, it is customary to use a beam stop to prevent the direct nonfocused beam from striking the detector. An alternative method would be the use of a pair of electrostatic quadrupoles with a central collimating orifice, as described below, to separate the state−selected beam from the parent beam. It is shown that, in general, a double quadrupole system with a central orifice has a much lower background signal and can have a larger transmission than the quadrupole system using a beam stop. The arguments given are for a lens system containing no field−free regions; the extension to a system with field−free regions is straightforward.
Reduction of spurious background peaks in electron spectrometers
Authors: Froitzheim H. , Ibach H. , Lehwald S.
Published: March 2003

Electron spectrometers working with electrostatic deflection are characterized by a typical background structure. Experimental investigations and model calculations for a 127° analyzer show that the major part of this background is caused by specular reflections of the electrons from the deflection plates towards the exit slits. The background is reduced by a factor ≳10 when the deflection plates are appropriately corrugated. In a comparison with the most rational general CFF available, that of Ermer and Lifson, the most significant discrepancies found to occur are those for certain stretch–bend couplings assumed to be zero in the CFF, but shown to be appreciable by quantum calculation. It is observed that these couplings, but not the stretch–stretch couplings, are well accounted for by a steric interaction model. The ab initio cubic constants examined display the same pattern of conformity with a steric model. Bend–bend–bend and bend–bend–stretch but not all stretch–stretch–stretch interactions agree with those of the steric model. The partial success of the steric model shows that it is possible to represent a large number of interaction constants, quadratic and higher order, by a small number of parameters in molecular mechanics. The failure of the steric model to account for predominantly stretching interactions confirms that ’’classical’’ nonbonded interactions as embodied in conventional Urey–Bradley fields are not the only major contributors to off-diagonal force constants. An alternative model, the anharmonic model of Warshel, as augmented by Kirtman et al., was found to account well for pure stretches but not for bends or stretch–bend interactions.
Versatile wide range precision spectrophotometer allowing simultaneous measurement of transmittance and reflectance
Authors: DeFonzo Alfred P.
Published: March 2003

An optical system is described having three equal paths split from a single beam and recombined into a single beam. A method for electronically processing the signal to obtain the transmittance and reflectance as well as an interfacing system, which allows complete programming of scans and direct data processing, is also described. The results of simultaneous measurements of transmittance and reflectance of amorphous As2S3 and the reflectance squared of crystalline germanium are presented in which a relative precision better than 1×10−4 was achieved. Also mentioned are various applications, such as differential reflectance and measurements with incandescent samples.
Improved recovery time in single coil pulsed NMR spectrometers
Authors: Garroway A. N. , Ware D.
Published: March 2003

A simple modification to a conventional single coil pulsed NMR spectrometer is described which damps the final stage of the transmitter at low rf levels. For an unmodified Bruker SXP spectrometer a receiver recovery time of 7.7 μsec is obtained at 60 MHz; this time improves to 5.5 μsec on adding the ’’low level damper.’’
Crossed-beam apparatus for simultaneous spectrophotometric observation and microwave exposure of biochemical samples
Authors: Allis John W. , Weil Claude M. , Janes David E.
Published: March 2003

A spectrophotometer has been adapted for use as a simultaneous observation–exposure system for irradiation of biochemical samples by 1.7–2.6 GHz electromagnetic radiation. A waveguide applicator is mounted vertically in the sample compartment of a Cary 15 spectrophotometer such that the sample can be placed simultaneously in the light path and in a slot in the applicator. A standard 1-cm path square cell contains the sample which is irradiated through the open top of the cuvette. Temperature of the sample and an unirradiated reference are monitored continuously without measurable interference from the microwave field. Temperature can be controlled within a few tenths of a degree between 15 ° and 40 °C, and an absorbed dose rate can be calculated using thermal measurement techniques. Microwave generator output and reflected power are monitored at all times. The frequency can be changed easily and standing waves minimized by adjusting a waveguide tuning section. The microwave energy within the basic frequency range can be applied as continuous wave or modulated. The quality of the absorption spectra is not measurably impaired, and the flexibility of the spectrophotometric technique remains intact.
Compact, magnetic recirculating pump for wide-range temperature and pressure operation
Authors: Mansoorian H. , Capps E. F. , Gielen H. L. , Eubank P. T. , Hall K. R.
Published: March 2003

This article presents a design for a simple, inexpensive magnetic recirculating pump. It consists of a piston and cylinder with a separate check valve which can be either normally open or normally closed. The interior offers minimal surface area for adsorption and, with proper dimensioning and material selection, the pump can operate over wide pressure and temperature ranges. A prototype model with cylinder dimensions 22.2 mm o.d.×15.9 mm i.d. ×6.35 cm circulates at 26 cm3/sec (10 cm of H2O differential pressure). The dimensions of the prototype allow an operable pressure range of 0⩽P⩽703 kg cm−2 at room temperature. The temperature range is 100⩽T⩽500 K.