bluuebunny/crossref_metadata_2025 huggingface dataset:
Agency nursing work in acute care settings: perceptions of hospital nursing managers and agency nurse providers
Authors: Manias Elizabeth , Aitken Robyn , Peerson Anita , Parker Judith , Wong Kitty
Published: June 2003

• There is a paucity of research in investigating agency nursing work from the perspectives of hospital nursing managers and agency nurse providers.

• This exploratory paper examines the hospital nursing managers' and agency nurse providers' perceptions and experiences of agency nursing work.

• Individual, in‐depth interviews were conducted with three agency nurse providers and eight hospital nursing managers. Because of the lack of previous research in this area, an exploratory, semi‐structured interviewing technique was deemed appropriate.

• Three major themes emerged from interview data: planning for ward allocation, communication and professionalism.

• In planning for ward allocation, hospital managers were primarily concerned with maintaining adequate numbers of nursing staff in the ward settings. A major concern for agency nurse providers was inappropriate allocation of temporary staff.

• Communication was valued in different ways. While hospital managers focused on communication between the agency nurse and other permanent members of the health care team, agency providers were concerned with exchanges between agencies and hospital organizations, and between the agencies and agency nurses.

• For both groups, responsibility for professional development and the status of agency nursing as a career choice for graduate and experienced nurses were the focal aspects for consideration.

• A limitation of this study is the small number of individual interviews conducted with hospital nursing managers and agency nurse providers. Nevertheless, the findings represent the views of 11 individuals in senior managerial roles.

• The findings reinforce the need to enhance collaboration between hospitals and nursing agencies, and to examine how divergent views of agency nursing work could be reconciled – with the aim of providing quality patient care.
Indices for studying urinary incontinence and levator ani function in primiparous women
Authors: Antonakos Cathy L. , Miller Janis M. , Sampselle Carolyn M.
Published: June 2003

• Urinary incontinence (UI) is a complex phenomenon that is prevalent in pregnant and parous women and requires the use of sophisticated measures to adequately reflect functioning of the continence system.

• The purpose of this study was to develop reliable and valid measures of UI and levator ani function for use in research and clinical settings.

• A Leakage Index (LI) and a Levator Ani Function Index (LAFI) were developed using data from a longitudinal study of primiparous women. Reliability and validity tests were conducted to: (i) estimate the internal consistency reliability of each index, (ii) determine whether the indices captured change in continence status and pelvic floor function during pregnancy through 1 year postpartum, and (iii) estimate association between the indices as a test of predictive validity.

• Cronbach's alpha ranged from 0.72 to 0.84 for the LI and from 0.53 to 0.79 for the LAFI across the six data collection time points of the study. Average LI scores increased late in pregnancy and decreased postpartum, though not significantly. Average LAFI scores decreased significantly at 35 weeks gestation (t = 4.84, P = 0.000) and increased significantly at 12 months postpartum (t = −3.51, P = 0.002) relative to baseline. The LI and LAFI were significantly associated at 20 weeks gestation (Pearson r = −0.40, P = 0.007) and at 6 weeks postpartum (Pearson r = −0.33, P = 0.029).

• The findings suggest the LI and LAFI are reliable and valid measures of UI and levator ani function in primiparous women, which can be used with confidence in clinical and research settings.
Lived experiences of eating problems for patients with head and neck cancer during radiotherapy
Authors: Larsson Maria , Hedelin Birgitta , Athlin Elsy
Published: June 2003

• Only a small proportion of cancer patients undergo radical radiotherapy to the head and neck, but their needs are particularly complex. Although extensive research describes the side‐effects of radiotherapy to the head and neck, few studies focus on patients' subjective experiences of eating problems and the impact these have on the patients' daily life.

• In this study a phenomenological approach was used, as the purpose was to acquire deeper understanding of head and neck cancer patients' lived experiences of eating problems, their consequences in daily life and patients' strategies of coping with these problems.

• Eight patients from two radiation therapy departments in mid‐Sweden were interviewed in an open dialogue. Data analysis was based on Colaizzi's method.

• Eating problems experienced were captured in two interrelated main themes: ‘Ability to chew and swallow’ and ‘Will and desire to eat’. The eating problems were found to cause a number of severe consequences in daily life. These are incorporated into one main theme: ‘The way of life is disturbed’. Ways to cope with this disturbance were captured in one main theme: ‘Trying to see the end – To survive’.

• This study identifies the need to view eating problems as a complex phenomenon in a specific context including the individual patient's life situation. The findings create the opportunity to develop nursing interventions based on patients' own needs. To facilitate this, a specialist nurse should be responsible for reviewing patients regularly throughout radiation therapy. Intervention studies are needed to provide optimal clinical guidelines.
Meanings of giving touch in the care of older patients: becoming a valuable person and professional
Authors: David Edvardsson Jan , Sandman Per‐Olof , Rasmussen Birgit H.
Published: June 2003

• Touch is central to nursing and health care workers frequently touch their patients, consciously or unconsciously in their interactions with them. Most literature has studied touch from a patient perspective, thus inquiry about professionals' experiences are rare.

• The aim of this study was to illuminate meanings of giving touch in nursing care of older patients.

• To understand the meaning of lived experiences of giving touch in care of older patients, interviews with 12 health care professionals in northern Sweden were analysed using a phenomenological–hermeneutic approach influenced by the philosophy of Ricoeur.

• The findings show that giving touch in the care of older patients is a transforming experience, where one suddenly perceives oneself as both a valuable person and professional who no longer powerlessly confronts patients' haunted and disrupted bodies, but who, by means of touch, has gained power to ease this suffering.

• The experience also transforms the way one regards older patients. Instead of seeing a severely demanding patient suffering from dementia and/or pain, one is able to see the person behind the disease as a human being, like oneself.

• A relationship described as calm, friendly and humane is created between caregiver and patient when giving touch, a relationship that transcends the moment of touch and influences one's way of caring. This understanding is presented using the theoretical framework of the philosophy of Marcel.

• Giving touch has the power to shed new light on health care professionals' experiences of caring for older patients suffering from dementia and/or pain, giving them the power to be a valuable person and professional.
Critical care nurses' use of decision‐making strategies
Authors: Aitken Leanne M.
Published: June 2003

• Effective decision‐making has the potential to facilitate improvements in health care. This paper reports several aspects of a study which used ‘thinking aloud’ within a concept attainment framework to examine the decision‐making processes of expert critical care nurses in relation to haemodynamic monitoring.

• The purpose of this study was to examine whether hypotheses were used in the decision‐making process and, if so, were hypotheses deactivated when no longer relevant. In addition, the strategies that were used during the decision‐making process were examined.

• Eight expert critical care nurses consented to participate in the study after ethics clearance was obtained from both the University and Hospital ethics committees.

• The majority of expert critical care nurse participants in this study demonstrated extensive use of hypotheses to explain the relationship between attributes and concepts.

• There was no evidence of specific deactivation of hypotheses when they were no longer relevant.

• Participants demonstrated use of a range of decision‐making strategies, with a Focus Gambling Strategy being the most common. The reason for using different decision‐making strategies was not clear and may represent variation between decision‐makers or between scenarios for each individual decision‐maker.

• Recommendations are made to help improve critical care nurses' decision‐making.
Prejunctional modulation of non‐adrenergic non‐cholinergic (NANC) inhibitory responses in the isolated guinea‐pig gastric fundus
Authors: Todorov S. , Pozzoli C. , Zamfirova R. , Poli E.
Published: June 2003

Abstract  The inhibitory neurotransmission of the stomach was investigated in isolated guinea‐pig gastric fundus. In preparations treated with guanethidine (1 μmol L−1) and p‐fluoro‐hexahydro‐sila‐difenidol (1 μmol L−1), electrical stimulation evoked neurogenic inhibitory responses not modified by hexamethonium (100 μmol L−1), suggesting that inhibitory postganglionic non‐adrenergic non‐cholinergic (NANC) nerve fibres are involved. The nitric oxide (NO)‐synthase inhibitor Nω‐nitro‐l‐argininine‐methyl‐ester hydrochloride (1–100 μmol L−1) and the soluble guanylyl cyclase inhibitor ODQ (0.1–3 μmol L−1) also abolished such relaxant response, suggesting the involvement of NO/Cyclic Guanosine 3′,5′ monophosphate (cGMP) system as the final mechanism of muscle relaxation. The α2‐adrenoceptor agonist, UK 14 304 (10 nmol L−1–10 μmol L−1) did not influence the electrical field stimulation (EFS)‐evoked NANC responses. These latter responses were also refractory to a variety of receptor agonists and antagonists, acting at Gamma Aminobutyric Acid (GABA), serotonin 5HT1a, opioid μ, δ and κ, muscarinic M1 and M2, histamine H2 and H3 and cannabinoid receptors. The NANC response was insensitive to the P/Q‐type Ca2+‐channel blocker ω‐agatoxin TK (1 nmol L−1–0.1 μ mol L−1), but partially inhibited by the N‐type Ca2+‐channel blocker ω‐conotoxin GVIA (0.1 nmol L−1−0.1 μmol L−1), and by the L‐type Ca2+‐channel blockers nifedipine and calcicludine (0.1 nmol L−1−0.1 μmol L−1). These data suggest that the NANC relaxation of the isolated guinea‐pig gastric fundus is mediated by NO as the final inhibitory (neuro)transmitter at the longitudinal smooth muscle cells. The mechanism(s) promoting NO production is/are Ca2+‐dependent, but apparently insensitive to presynaptic modulation. Both N‐ and L‐type channels seem to occur in nitrergic nerve endings, where they contribute to trigger NO diffusion at the synaptic cleft.
Slowing of intestinal transit by fat depends on an ondansetron – sensitive, efferent serotonergic pathway
Authors: Lin H. C. , Chen J. H.
Published: June 2003

Abstract  The ileal brake is a neural reflex that slows proximal small bowel transit when fat enters the distal small bowel. In rats, ondansetron, a 5‐hydroxytryptamine‐3 (5‐HT3)‐receptor antagonist, abolishes the ileal brake. However, the location of this serotonergic pathway is unknown. Of the known enteric sites responsive to 5‐hydroxytryptamine (5‐HT), only the myenteric neurone is equipped with 5‐HT3 receptors and is located on the efferent limb of reflex response. The aim of this study was to test the hypothesis that slowing of intestinal transit by fat may depend on an ondansetron‐sensitive serotonergic pathway located on the efferent limb of this reflex response. In a fistulated dog model that compartmentalized the afferent from the efferent limb of the ileal brake response, ondansetron was delivered luminally into the distal (afferent) or proximal (efferent) half of the small bowel to localize the serotonergic pathway. It was found that activating the ileal brake slowed down the proximal intestinal transit to 30% of control values. The ileal brake was abolished when ondansetron was delivered into the proximal but not the distal small bowel. Our data supports the hypothesis that the 5‐HT receptors participating in the ileal brake are on the efferent limb of this neural reflex, possibly on myenteric neurones.
Murine intestinal migrating motor complexes: longitudinal components
Authors: Powell A. K. , Bywater R. A. R.
Published: June 2003

Spontaneous migrating contractions have been described in the circular muscle of the isolated mouse colon and terminal ileum, however, spontaneous events equivalent to these have not been reported in the longitudinal muscle. The longitudinal muscle shortenings in the colon and ileum, which are of similar form, frequency and pharmacology to the circular muscle colonic and ileal migrating motor complexes (CMMCs and IMMCs), are recorded in the present study. The spontaneous ileal and colonic longitudinal muscle shortenings appear to be neurally organized as they are abolished by tetrodotoxin (1 μmol L−1), hexamethonium (500 μmol L−1) and morphine (1 μmol L−1). Endogenously released nitric oxide slowed the frequency of spontaneous ileal and colonic longitudinal muscle shortenings and 5‐hydroxytryptamine increased their frequency. Hyoscine (1 μmol L−1) abolished longitudinal shortenings in the ileum and reduced the amplitude of longitudinal shortening by ∼44% in the colon. Shortenings were effectively abolished by nifedipine (1 μmol L−1). Surgical sectioning of the colon identified that each region of the colon contracted longitudinally in an independent fashion; the distal colon contracted to the greatest amplitude and lowest frequency. The longitudinal preparation is suitable to initially assess the actions of novel pharmacological agents on spontaneous, neurally coordinated, CMMCs and IMMCs in emptied isolated murine intestines.
The role of the cytoskeleton in capacitaftive calcium entry in myenteric glia
Authors: Lin T. , Zhang W. , Garrido R. , Segura B. , Hu Y. , Guzman E. , Mulholland M.
Published: June 2003

Capacitative calcium entry (CCE) is the process by which intracellular calcium is replenished from the external milieu upon depletion of intracellular stores. CCE is thought to participate in chemotaxis, proliferation and cell signalling. A physical interaction between intracellular stores and the plasma membrane is postulated to regulate CCE. We hypothesized that cytoskeletal disruption alters this interaction, inhibiting CCE in enteric glia. Cultured myenteric glia from neonatal guinea‐pigs were treated with cytochalasin D (10 μmol L−1), a microfilament disrupting agent, nocodazole (20 μmol L−1), a microtubule disrupting agent, or vehicle (dimethyl sulphoxide). Intracellular calcium changes were measured using fura‐2 microfluorimetry. To evaluate the rate of cation re‐entry, barium was substituted for calcium because barium is not sequestered internally. Cytochalasin D‐treated glia had diminished CCE responses (57 ± 3 nmol L−1) compared with controls (97 ± 7 nmol L−1) as did nocodazole‐treated glia (30 ± 2 nmol L−1) vs controls (77 ± 6 nmol L−1). The proportion of cells demonstrating CCE abolition was greater in the cytochalasin (50 ± 8%) and nocodazole‐treated (89 ± 2%) groups compared with controls (21 ± 2%, 40 ± 9%, respectively). Cytochalasin D and nocodazole treatment diminished the rate of cation re‐entry based on diminished barium entry in treated vs control cells. From this study, we conclude that disruption of cytoskeletal elements diminishes calcium influx essential to calcium store repletion in myenteric glia.
Interdigestive small bowel motility and duodenal bacterial overgrowth in experimental acute pancreatitis
Authors: Van felius I. D. , Akkermans L. M. A. , Bosscha K. , Verheem A. , Harmsen W. , Visser M. R. , Gooszen H. G.
Published: June 2003

Abstract The objective of this study is to investigate the effects of an acute necrotizing pancreatitis (ANP), without biliary obstruction, on the migrating motor complex (MMC), small bowel bacterial overgrowth (SBBO), bacterial translocation (BT) and infection of the pancreas simultaneously. Rats were divided into four groups: mild pancreatitis, control, ANP and sham operated control. Jejunal myoelectrodes were used to measure MMCs. Blood, peritoneal fluid, bile, and abdominal organs were harvested for microbial culturing 72 h after induction of pancreatitis. The splenic portion of the pancreas was taken for histology. During ANP the MMC cycle length was significantly increased from 14.1 ± 0.2 to 22.4 ± 1.9 min (P < 0.05). The duodenum of ANP rats was in contrast with the other groups characterized by Enterobacteriacae (> 3 log 10 CFU g−1 in seven of 12 rats, P < 0.05). A positive correlation (r = 0.78, P < 0.01) existed between duodenal Gram‐negative and anaerobic flora and the MMC cycle. Correlation between MMC cycle length and BT to the pancreas was positive as well (r = 0.70, P < 0.01). A positive correlation (r = 0.85, P < 0.01) was found between the severity of pancreatitis and duodenal bacterial overgrowth. During ANP without biliary obstruction, the jejunal MMC is disturbed and consequently SBBO occurs. The correlation between the severity of pancreatitis, the disturbance of the MMC and SBBO suggests an important pathophysiological role of the proximal small bowel in the infection of pancreatic necrosis.
Pro‐inflammatory (IL‐1β, IL‐18) cytokines and IL‐8 chemokine release by PBMC in response to Echinococcus multilocularis metacestode vesicles
Authors: Eger Alexandra , Kirch Astrid , Manfras B. , Kern P. , Schulz‐Key H. , Soboslay P. T.
Published: June 2003

In humans infected with Echinococcus multilocularis, larval metacestodes will develop, proliferate and progressively infiltrate the surrounding host tissues by exogenous budding of parasitic microvesicles or cell lines which detach from the original tumour and thus become transported through blood or lymph vessels into other organs. Cellular effector mechanisms constitute the most effective means to restrict parasite persistence and proliferation, and here we demonstrate that E. multilocularis vesicle antigens will induce pro‐inflammatory, regulatory and chemokine release by PBMC from patients. The pro‐inflammatory cytokines IL‐1β and IL‐18 were reduced in echinococcosis patients, regulatory IL‐10 was similar, but parasite vesicle‐induced IL‐8 was dominant and clearly elevated in patients. Such selective and opposite dynamics of inflammatory cytokines and chemokine release may prevent overwhelming and pathogenic inflammation, and constitute an appropriate response for attraction of effector cells into the periparasitic tissues with the capacity to limit E. multilocularis metacestode proliferation and dissemination.
Antigenemia is associated with low antibody response to carbohydrate determinants of a filarial surface antigen
Authors: Bal M. S. , Beuria M. K. , Mandal N. N. , Das M. K.
Published: June 2003

The IgG response to a filarial surface antigen (DssdI) was evaluated in circulating antigen (Og4C3 test) positive and negative individuals from the Wuchereria bancrofti endemic region of Orissa, India. Circulating filarial antigen (CFA) positive individuals exhibited depressed antibody levels to DssdI and individuals with high antibody levels were invariably CFA negative. Low IgG levels to DssdI are associated with CFA positivity irrespective of microfilaraemia and clinical status. Thus asymptomatic microfilaraemic individuals with antigen positivity exhibited low IgG levels similar to symptomatic (chronic filariasis with elephantiasis, hydrocele) or asymptomatic amicrofilaraemic individuals with antigenemia. Western blot analysis revealed a band of approximately 210 kDa reactive with CFA‐negative, but not with CFA‐positive sera. DssdI was subjected to mild periodate oxidation to investigate the role of carbohydrate epitopes. The treatment considerably reduced the antigenic recognition of DssdI, stressing the immunodominance of carbohydrate residues of DssdI in infection‐free individuals. In contrast, individuals with active infection failed to produce such antibodies to filarial surface carbohydrates.
Characterization of a recombinant immunomodulatory protein from the salivary glands of Dermacentor andersoni
Authors: Alarcon‐Chaidez Francisco J. , Müller‐Doblies Uwe U. , Wikel Stephen
Published: June 2003

The gene encoding a 36‐kDa (p36) immunomodulatory protein present in saliva of Dermacentor andersoni was cloned in prokaryotic and eukaryotic expression vectors. A polymerase chain reaction (PCR)‐generated cDNA lacking signal peptide was cloned into the Escherichia coli expression vector pET28 and a similar sequence was cloned into pIB/V5‐His‐TOPO expression vector for stable transfection of insect cells, High 5™. The 26‐kDa molecular mass of p36 expressed by bacteria is in agreement with that predicted from the translated full‐length cDNA sequence. Eukaryotic‐cell‐expressed p36 consisted of multiple forms with molecular masses between 34 and 36 kDa. These multiple forms were attributed to differences in post‐translational modifications. N‐linked mannose was detected on insect‐cell‐expressed and tick‐derived p36. Multiple bands remained after endoglycosidase removal of N‐linked sugars, indicating the presence of other modifications. Both bacterial‐ and insect‐cell‐expressed p36 reacted on immunoblots with polyclonal antibodies raised against tick‐derived p36. Insect‐cell‐expressed p36 suppressed T‐lymphocyte‐mitogen‐driven in vitro proliferation of splenocytes from tick‐naïve mice in a dose‐dependent manner. Bacterial‐cell‐expressed p36 lacked immunomodulatory activity.
An improved, simple screening method for detection of glucose‐6‐phosphate dehydrogenase deficiency
Authors: Tantular Indah S. , Kawamoto Fumihiko
Published: June 2003

We established a new, simple and rapid screening method for detection of glucose‐6‐phosphate dehydrogenase (G6PD)‐deficiency by using a new formazan substrate, 2‐(2‐methoxy‐4‐nitrophenyl)‐3‐(4‐nitrophenyl)‐5‐(2,4‐disulfophenyl)‐2H tetrazolium monosodium salt (WST‐8) with a hydrogen carrier of 1‐methoxyphenazine methosulfate (1‐methoxy PMS), instead of a combination of 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2H tetrazolium bromide (MTT) and phenazine methosulfate (PMS), as used in many previous formazan methods. WST‐8 does not react with haemoglobin, and the formed formazan is highly water‐soluble, differing from MTT. Thus, the whole procedure can be performed in aqueous solution in a tube or well without any special equipment other than micropipettes. Within 1 h at room temperature, the strong orange colour of the WST‐8 formazan formed in normal blood samples could be distinguished, by naked eye, from G6PD‐deficient blood samples with less than 50% residual activity. We also found that reagents in the WST‐8/1‐methoxy PMS method were more resistant against exposure to sunlight than those in an MTT/PMS method. As the new method is both qualitative and quantitative, it is possible to express G6PD activity as increase of NADPH concentration by reading absorbance at 460 nm after incubation for 30 or 60 min.
Comparative efficacies of oral ketoconazole and terbinafine for reducingMalasseziapopulation sizes on the skin of Basset Hounds
Authors: Guillot Jacques , Bensignor Emmanuel , Jankowski François , Seewald Wolfgang , Chermette René , Steffan Jean
Published: June 2003

AbstractThe objective of this study was to compare the efficacy of oral ketoconazole and terbinafine for reducing population sizes ofMalasseziayeasts on canine skin. Twenty‐one Basset Hounds were randomised in three groups of seven according toMalasseziapopulations. Dogs in the first group were treated by oral administration of ketoconazole (Ketofungol® 200 mg, Janssen‐Cilag) at 10 mg kg−1, every 24 h with food, for 3 weeks. Dogs in the second group were treated by oral administration of terbinafine (Lamisil® 250 mg, Novartis) at 30 mg kg−1, every 24 h with food, for 3 weeks. The seven remaining dogs were used as controls.Malasseziapopulation sizes were assessed by use of contact plates on four cutaneous sites at days 7, 14 and 21. Both ketoconazole and terbinafine were effective in reducing the baseline levels ofMalasseziaorganisms with no significant difference between the two drugs. In further studies, oral terbinafine should be evaluated for the management of canine cases ofMalasseziadermatitis.
The crystal structure of annexin Gh1 from Gossypium hirsutum reveals an unusual S3 cluster
Authors: Hofmann Andreas , Delmer Deborah P. , Wlodawer Alexander
Published: June 2003

The three‐dimensional crystal structure of recombinant annexin Gh1 from Gossypium hirsutum (cotton fibre) has been determined and refined to the final R‐factor of 0.219 at the resolution of 2.1 Å. This plant annexin consists of the typical ‘annexin fold’ and is similar to the previously solved bell pepper annexin Anx24(Ca32), but significant differences are seen when compared to the structure of nonplant annexins. A comparison with the structure of the mammalian annexin AnxA5 indicates that canonical calcium binding is geometrically possible within the membrane loops in domains I and II of Anx(Gh1) in their present conformation. All plant annexins possess a conserved tryptophan residue in the AB loop of the first domain; this residue was found to adopt both a loop‐in and a loop‐out conformation in the bell pepper annexin Anx24(Ca32). In Anx(Gh1), the conserved tryptophan residue is in a surface‐exposed position, half way between both conformations observed in Anx24(Ca32). The present structure reveals an unusual sulfur cluster formed by two cysteines and a methionine in domains II and III, respectively. While both cysteines adopt the reduced thiolate forms and are separated by a distance of about 5.5 Å, the sulfur atom of the methionine residue is in their close vicinity and apparently interacts with both cysteine sulfur atoms. While the cysteine residues are conserved in at least five plant annexins and in several mammalian members of the annexin family of proteins, the methionine residue is conserved only in three plant proteins. Several of these annexins carrying the conserved residues have been implicated in oxidative stress response. We therefore hypothesize that the cysteine motif found in the present structure, or possibly even the entire sulfur cluster, forms the molecular basis for annexin function in oxidative stress response.
On peptide bond formation, translocation, nascent protein progression and the regulatory properties of ribosomes
Authors: Agmon Ilana , Auerbach Tamar , Baram David , Bartels Heike , Bashan Anat , Berisio Rita , Fucini Paola , Hansen Harly A. S. , Harms Joerg , Kessler Maggie , Peretz Moshe , Schluenzen Frank , Yonath Ada , Zarivach Raz
Published: June 2003

High‐resolution crystal structures of large ribosomal subunits from Deinococcus radiodurans complexed with tRNA‐mimics indicate that precise substrate positioning, mandatory for efficient protein biosynthesis with no further conformational rearrangements, is governed by remote interactions of the tRNA helical features. Based on the peptidyl transferase center (PTC) architecture, on the placement of tRNA mimics, and on the existence of a two‐fold related region consisting of about 180 nucleotides of the 23S RNA, we proposed a unified mechanism integrating peptide bond formation, A‐to‐P site translocation, and the entrance of the nascent protein into its exit tunnel. This mechanism implies sovereign, albeit correlated, motions of the tRNA termini and includes a spiral rotation of the A‐site tRNA‐3′ end around a local two‐fold rotation axis, identified within the PTC. PTC features, ensuring the precise orientation required for the A‐site nucleophilic attack on the P‐site carbonyl‐carbon, guide these motions. Solvent mediated hydrogen transfer appears to facilitate peptide bond formation in conjunction with the spiral rotation. The detection of similar two‐fold symmetry‐related regions in all known structures of the large ribosomal subunit, indicate the universality of this mechanism, and emphasizes the significance of the ribosomal template for the precise alignment of the substrates as well as for accurate and efficient translocation. The symmetry‐related region may also be involved in regulatory tasks, such as signal transmission between the ribosomal features facilitating the entrance and the release of the tRNA molecules. The protein exit tunnel is an additional feature that has a role in cellular regulation. We showed by crystallographic methods that this tunnel is capable of undergoing conformational oscillations and correlated the tunnel mobility with sequence discrimination, gating and intracellular regulation.
An ‘Old World’ scorpion β‐toxin that recognizes both insect and mammalian sodium channels
Authors: Gordon Dalia , Ilan Nitza , Zilberberg Noam , Gilles Nicolas , Urbach Daniel , Cohen Lior , Karbat Izhar , Froy Oren , Gaathon Ariel , Kallen Roland G. , Benveniste Morris , Gurevitz Michael
Published: June 2003

Scorpion toxins that affect sodium channel (NaCh) gating in excitable cells are divided into α‐ and β‐classes. Whereas α‐toxins have been found in scorpions throughout the world, anti‐mammalian β‐toxins have been assigned, thus far, to ‘New World’ scorpions while anti‐insect selective β‐toxins (depressant and excitatory) have been described only in the ‘Old World’. This distribution suggested that diversification of β‐toxins into distinct pharmacological groups occurred after the separation of the continents, 150 million years ago. We have characterized a unique toxin, Lqhβ1, from the ‘Old World’ scorpion, Leiurus quinquestriatus hebraeus, that resembles in sequence and activity both ‘New World’β‐toxins as well as ‘Old World’ depressant toxins. Lqhβ1 competes, with apparent high affinity, with anti‐insect and anti‐mammalian β‐toxins for binding to cockroach and rat brain synaptosomes, respectively. Surprisingly, Lqhβ1 also competes with an anti‐mammalian α‐toxin on binding to rat brain NaChs. Analysis of Lqhβ1 effects on rat brain and Drosophila Para NaChs expressed in Xenopus oocytes revealed a shift in the voltage‐dependence of activation to more negative membrane potentials and a reduction in sodium peak currents in a manner typifying β‐toxin activity. Moreover, Lqhβ1 resembles β‐toxins by having a weak effect on cardiac NaChs and a marked effect on rat brain and skeletal muscle NaChs. These multifaceted features suggest that Lqhβ1 may represent an ancestral β‐toxin group in ‘Old World’ scorpions that gave rise, after the separation of the continents, to depressant toxins in ‘Old World’ scorpions and to various β‐toxin subgroups in ‘New World’ scorpions.
Acid microenvironments in microbial biofilms of antarctic endolithic microecosystems
Authors: Los Ríos Asunción , Wierzchos Jacek , Sancho Leopoldo G. , Ascaso Carmen
Published: June 2003

Antarctic endolithic microecosystems harbour distinct biofilms. The lithic substrate and the microorganisms comprising these films are intimately linked, leading to complex mineral–microbe interactions. Hence, the microhabitats and microenvironments of these microecosystems are not only determined by the physicochemical features of the lithic substrate, but are also conditioned by the biological components of these biofilms. The Antarctic biofilms analysed in this study are characterized by the presence of extracellular polymer substances and acid microenvironments in the proximity of the cells; cyanobacteria appearing as key components. On ultrastructural analysis, these endolithic cyanobacteria showed differences in sheath organization, probably related to their spatial position in the lithic substrate. It is proposed that in this type of ecosystem, biofilm structure could favour the formation of microsites with specific physicochemical conditions appropriate for the survival of microbial communities in this extreme environment.
Dimethyl sulphide and methanethiol formation in microbial mats: potential pathways for biogenic signatures
Authors: Visscher Pieter T. , Baumgartner Laura K. , Buckley Daniel H. , Rogers Daniel R. , Hogan Mary E. , Raleigh Christopher D. , Turk Kendra A. , Des Marais David J.
Published: June 2003

Mechanisms of dimethyl sulphide (DMS) and methanethiol (MT) production and consumption were determined in moderately hypersaline mats, Guerrero Negro, Mexico. Biological pathways regulated the net flux of DMS and MT as revealed by increases in flux resulting from decreased salinity, increased temperature and the removal of oxygen. Dimethylsulphoniopropionate (DMSP) was not present in these microbial mats and DMS and MT are probably formed by the reaction of photosynthetically produced low‐molecular weight organic carbon and biogenic hydrogen sulphide derived from sulphate reduction. These observations provide an alternative to the notion that DMSP or S‐containing amino acids are the dominant precursors of DMS in intertidal sediment systems. The major sink for DMS in the microbial mats was biological consumption, whereas photochemical oxidation to dimethylsulphoxide was the major sink for DMS in the overlying water column. Diel flux measurements demonstrated that significantly more DMS is released from the system during the night than during the day. The major consumers of DMS in the presence of oxygen were monooxygenase‐utilizing bacteria, whereas under anoxic conditions, DMS was predominantly consumed by sulphate‐reducing bacteria and methanethiol was consumed by methanogenic bacteria. Aerobic and anaerobic consumption rates of DMS were nearly identical. Mass balance estimates suggest that the consumption in the water column is likely to be smaller than net the flux from the mats. Volatile organic sulphur compounds are thus indicators of high rates of carbon fixation and sulphate reduction in these laminated sediment ecosystems, and atmospheric sulphur can be generated as a biogenic signature of the microbial mat community.
Reproduction and metabolism at − 10°C of bacteria isolated from Siberian permafrost
Authors: Bakermans Corien , Tsapin Alexandre I. , Souza‐Egipsy Virginia , Gilichinsky David A. , Nealson Kenneth H.
Published: June 2003

We report the isolation and properties of several species of bacteria from Siberian permafrost. Half of the isolates were spore‐forming bacteria unable to grow or metabolize at subzero temperatures. Other Gram‐positive isolates metabolized, but never exhibited any growth at − 10°C. One Gram‐negative isolate metabolized and grew at − 10°C, with a measured doubling time of 39 days. Metabolic studies of several isolates suggested that as temperature decreased below + 4°C, the partitioning of energy changes with much more energy being used for cell maintenance as the temperature decreases. In addition, cells grown at − 10°C exhibited major morphological changes at the ultrastructural level.
Shifts in archaeal communities associated with lithological and geochemical variations in subsurface Cretaceous rock
Authors: Takai Ken , Mormile Melanie R. , McKinley James P. , Brockman Fred J. , Holben William E. , Kovacik William P. , Fredrickson Jim K.
Published: June 2003

Subsurface microbial community structure in relation to geochemical gradients and lithology was investigated using a combination of molecular phylogenetic and geochemical analyses. Discreet groundwater and substratum samples were obtained from depths ranging from 182 to 190 m beneath the surface at approximately 10‐cm intervals using a multilevel sampler (MLS) that straddled Cretaceous shale and sandstone formations at a site in the southern San Juan Basin in New Mexico. DNA and RNA were extracted directly from quartzite sand substratum loaded into individual cells of the MLS and colonized in situ. Polymerase chain reaction (PCR)‐mediated T‐RFLP analysis of archaeal rRNA genes (rDNA) in conjunction with partial sequencing analysis of archaeal rDNA libraries and quantitative RNA hybridization with oligonucleotide probes were used to probe community structure and function. Although total microbial populations remained relatively constant over the entire depth interval sampled, significant shifts in archaeal populations, predominantly methanogens, were observed. These shifts coincided with the geochemical transition from relatively high methane (26 mM), low sulphate (< 3 mg l−1) conditions in the region adjacent to the organic matter‐rich shale to relatively low‐methane (< 0.5 mM), high‐sulphate (48 mg l−1) conditions in the organic‐poor sandstone beneath the shale. These results indicated that active, phylogenetically diverse archaeal communities were present in the subsurface Cretaceous rock environment at this site and that major archaeal clades shifted dramatically over scales of tens of centimetres, corresponding to changes in the lithology and geochemical gradients.
A cohort study of reproductive risk factors, weight and weight change and the development of diabetes mellitus
Authors: Dawson S. I. , Smith W. C. S. , Watson M. S. , Wilson B. J. , Prescott G. J. , Campbell D. , Hannaford P.
Published: June 2003

Aims:  Reproductive factors (parity, miscarriages, terminations), oral contraceptive use, hormone replacement therapy, body weight at first pregnancy and weight gain following pregnancy may be associated with a long‐term risk of diabetes. The aim of this study is to investigate the independent risks of reproductive factors and body weight for diabetes in later life.

Methods:  This is a retrospective cohort study of 1257 parous women who had a first pregnancy between 1951 and 1970. Reproductive history, weight and height were measured at the time of first pregnancy, then assessed by questionnaire in 1997 for all women. A clinical examination and an analysis of blood samples were undertaken for 992 women. The main outcome was incidence of diabetes based on medical history, medication and random glucose measurement.

Results:  Sixty of the 1257 (4.8%) women developed diabetes. Body mass index at index pregnancy and after 28–48 years follow‐up were both significantly associated with risk of diabetes, this increased with greater weight gain. There was a non‐significant increased risk of diabetes associated with stillbirths and miscarriages after age and BMI adjustment.

Conclusions:  In parous women, higher BMI at index pregnancy, weight gain during follow‐up and BMI in later life strongly predict diabetes risk.
Uncertain clinical utility of contemporary strategies for microalbuminuria testing
Authors: Baskar V. , Kamalakannan D. , Holland M. R. , Catchpole C. R. , Singh B. M.
Published: June 2003

Aims:  To determine whether conventional dipstick tests for proteinuria accurately identified patients with diabetic nephropathy and whether repeat testing for elevated albumin excretion and screening for urinary tract infection was required as part of the screening process for microalbuminuria.

Methods:  Random urine for albumin/creatinine ratio (ACR) was measured in all patients over a 6‐month period. Patients who had a positive test (>3.5 mg/mmol) were requested to provide two further samples for re‐testing and a mid‐stream urine specimen to screen for asymptomatic bacteriuria. The evaluation of accuracy of dipstick proteinuria was carried out in the samples collected over a fixed 2‐week period.

Results:  Dipstick vs. ACR – Of 221 samples collected, 142 were negative, 58 had 1+ and 21 had 2+ or more for dipstick proteinuria. At a threshold of 2+, the majority (81%) had ACR in the overt nephropathy range (>30 mg/mmol) and none had it below 10 mg/mmol, whereas at 1+, only 28% had ACR in the overt nephropathy range and 19% even had normoalbuminuria. Repeat Testing – Of the 1832 patients who had microalbuminuria measured, 673 had a positive test and 248 returned repeat samples. Eighty‐one patients returned two samples, of which 16 had discordant results, and 161 patients gave three samples, of which only 23 were false positives. The majority of these 39 patients had low‐grade microalbuminuria (ACR 3.5–10 mg/mmol) in their first sample. The absolute benefit of repeat testing was only to 3.4% of the population who screened positive, while in a further 2.3% (two‐sample responders) there was potential for confusion because of discordant results. Infection Screening – Of the 248 samples, only 31 had evidence of urinary infection.

Conclusion:  Dipstick proteinuria of 1+ does not necessarily represent significant nephropathy. There is little or no benefit in repeat testing outside of the low microalbuminuria range but compliance to such testing is poor. Screening for asymptomatic bacteriuria as part of microalbuminuria screening is of questionable value.
The conus valves of the adult gilthead seabream (Sparus auratus)
Authors: Icardo J. M. , Schib J. L. , Ojeda J. L. , Durán A. C. , Guerrero A. , Colvee E. , Amelio D. , Sans‐Coma V.
Published: June 2003

The conus (bulbo‐ventricular) valves of teleosts perform a key function in the control of blood backflow during ventricular diastole. However, the structural characteristics of these valves are almost unknown. This paper presents a systematic anatomical, histological and structural study of the conus valves of the adult gilthead seabream (Sparus auratus). S. auratus shows two major left and right valves consisting of the leaflet and the supporting sinus. Each valvar leaflet can be divided into a stout proximal body and a flap‐like distal region. The proximal body is structured into three layers: a luminal fibrosa, a dense cellular core and a parietal fibrosa. The luminal fibrosa is a collagenous structure extending the entire length of the leaflet, while the parietal fibrosa is restricted to the most proximal area. The dense cellular core consists of fibroblastic cells and a matrix rich in glycoconjugates, collagen and elastin. The histochemical and structural data suggest that the luminal fibrosa bears most of the force associated with valvar closure, while the cellular core acts as a cushion dampening vibrations and absorbing the elastic recoil. The sinus wall is a fibrous layer which shows proximal–distal differences in thickness. It also shows compositional differences that can be related to mechanical function. We describe the presence of a fibrous cylinder formed by the sinus wall, the fibrous interleaflet triangles and the fibrous layer that covers the inner surface of the conus myocardium. This fibrous cylinder constitutes the structural nexus between the ventricle, the conus and the bulbus arteriosus, provides support for the conus valves and separates the valvar complex from the surrounding tissues. The structure of the conus valves in S. auratus is different from that found in other vertebrates. Anatomical similarities between the conus valves and the mammalian arterial valves are emphasized. Each phyletic group appears to have developed specific structures in order to perform similar functions.
Developing best practice in critical care nursing: knowledge, evidence and practice
Authors: Fulbrook Paul
Published: June 2003

Because the current drive towards evidence‐based critical care nursing practice is based firmly within the positivist paradigm, experimentally derived research tends to be regarded as ‘high level’ evidence, whereas other forms of evidence, for example qualitative research or personal knowing, carry less weight

This poses something of a problem for nursing, as the type of knowledge nurses use most in their practice is often at the so‐called ‘soft’ end of science. Thus, the ‘Catch 22’ situation is that the evidence base for nursing practice is considered to be weak

Furthermore, it is argued in this paper that there are several forms of nursing knowledge, which critical care nurses employ, that are difficult to articulate

The way forward requires a pragmatic approach to evidence, in which all forms of knowledge are considered equal in abstract but are assigned value according to the context of a particular situation

It is proposed that this can be achieved by adopting an approach to nursing in which practice development is the driving force for change
A bereavement after‐care service for intensive care relatives and staff: the story so far
Authors: Williams Rachel , Harris Samantha , Randall Lynn , Nichols Rhonda , Brown Sally
Published: June 2003

The Intensive Care Society (1998) developed Guidelines for Bereavement Care in Intensive Care Units

In response to the guidelines, a group of nurses from the intensive care units at Glenfield Hospital in Leicester have developed a bereavement after‐care service for relatives and staff

So far, the service has evaluated well from the feedback received from both relatives and staff, but evaluation is ongoing and the service is being continually developed
Developing and evaluating critical care follow‐up
Authors: Cutler Lee , Brightmore Kerry , Colqhoun Val , Dunstan Julie , Gay Marilyn
Published: June 2003

The effects of critical illness not only affect the patient and relative during the intensive care stay but often affect for a considerable time afterwards

A growing body of opinion and evidence suggests that many of the needs of those who have been critically ill can be met through critical care follow‐up services

A growing number of follow‐up services now exist. Their establishment, development and evaluation pose significant challenges for those involved

This paper describes Bassetlaw hospital's critical care follow‐up service, how it was established and what an elementary service evaluation project has shown

The findings and experiences are compared with others in published literature, and the paper may be of interest to those who are currently involved in follow‐up or who plan to develop such services in the future