bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structures of S. aureus thymidylate kinase reveal an atypical active site configuration and an intermediate conformational state upon substrate binding
Authors: Kotaka Masayo , Dhaliwal Balvinder , Ren Jingshan , Nichols Charles E. , Angell Richard , Lockyer Michael , Hawkins Alastair R. , Stammers David K. 
Published: March 2006

AbstractMethicillin‐resistant Staphylococcus aureus (MRSA) poses a major threat to human health, particularly through hospital acquired infection. The spread of MRSA means that novel targets are required to develop potential inhibitors to combat infections caused by such drug‐resistant bacteria. Thymidylate kinase (TMK) is attractive as an antibacterial target as it is essential for providing components for DNA synthesis. Here, we report crystal structures of unliganded and thymidylate‐bound forms of S. aureus thymidylate kinase (SaTMK). His‐tagged and untagged SaTMK crystallize with differing lattice packing and show variations in conformational states for unliganded and thymidylate (TMP) bound forms. In addition to open and closed forms of SaTMK, an intermediate conformation in TMP binding is observed, in which the site is partially closed. Analysis of these structures indicates a sequence of events upon TMP binding, with helix α3 shifting position initially, followed by movement of α2 to close the substrate site. In addition, we observe significant conformational differences in the TMP‐binding site in SaTMK as compared to available TMK structures from other bacterial species, Escherichia coli and Mycobacterium tuberculosis as well as human TMK. In SaTMK, Arg 48 is situated at the base of the TMP‐binding site, close to the thymine ring, whereas a cis‐proline occupies the equivalent position in other TMKs. The observed TMK structural differences mean that design of compounds highly specific for the S. aureus enzyme looks possible; such inhibitors could minimize the transfer of drug resistance between different bacterial species.
Functional contribution of a conserved, mobile loop histidine of phosphoribulokinase
Authors: Runquist Jennifer A. , Miziorko Henry M. 
Published: March 2006

AbstractIn the Rhodobacter sphaeroides phosphoribulokinase (PRK) structure, there are several disordered regions, including a loop containing invariant residues Y98 and H100. The functional importance of these residues has been unclear. PRK is inactivated by diethyl pyrocarbonate (DEPC) and protected by the substrates ATP and Ru5P, as well as by the competitive inhibitor, 6‐phosphogluconate, suggesting active site histidine residue(s). PRK contains only three invariant histidines: H45, H100, and H134. Previous mutagenesis studies discount significant function for H134, but implicate H45 in Ru5P binding. PRK mutant H45N is inactivated by DEPC, implicating a second active site histidine. To evaluate the function of H100, as well as another invariant loop residue Y98, PRK mutants Y98L, H100A, H100N, and H100Q were characterized. Mutant PRK binding stoichiometries for the fluorescent alternative substrate, trinitrophenyl‐ATP, as well as the allosteric activator, NADH, are comparable to wild‐type PRK values, suggesting intact effector and substrate binding sites. The KmRu5P for the H100 mutants shows modest eight‐ to 14‐fold inflation effects, whereas Y98L exhibits a 40‐fold inflation for KmRu5P. However, Y98L's Ki for the competitive inhibitor 6‐phosphogluconate is close to that of wild‐type PRK. These observations suggest that Y98 and H100 are not essential Ru5P binding determinants. The Vm of Y98L is diminished 27‐fold compared with wild‐type PRK. In contrast, H100A, H100N, and H100Q exhibit significant decreases in Vm of 2600‐, 2300‐, and 735‐fold, respectively. Results suggest that the mobile region containing Y98 and H100 must contribute to PRK's active site. Moreover, H100's imidazole significantly influences catalytic efficiency.
Crystal structure of Homo sapiens PTD012 reveals a zinc‐containing hydrolase fold
Authors: Manjasetty Babu A. , Büssow Konrad , Fieber‐Erdmann Martin , Roske Yvette , Gobom Johan , Scheich Christoph , Götz Frank , Niesen Frank H. , Heinemann Udo 
Published: March 2006

AbstractThe human protein PTD012 is the longer product of an alternatively spliced gene and was described to be localized in the nucleus. The X‐ray structure analysis at 1.7 Å resolution of PTD012 through SAD phasing reveals a monomeric protein and a novel fold. The shorter splice form was also studied and appears to be unfolded and non‐functional. The structure of PTD012 displays an αββα four‐layer topology. A metal ion residing between the central β‐sheets is partially coordinated by three histidine residues. X‐ray absorption near‐edge structure (XANES) analysis identifies the PTD012‐bound ion as Zn2+. Tetrahedral coordination of the ion is completed by the carboxylate oxygen atom of an acetate molecule taken up from the crystallization buffer. The binding of Zn2+ to PTD012 is reminiscent of zinc‐containing enzymes such as carboxypeptidase, carbonic anhydrase, and β‐lactamase. Biochemical assays failed to demonstrate any of these enzyme activities in PTD012. However, PTD012 exhibits ester hydrolase activity on the substrate p‐nitrophenyl acetate.
Antibody targeting of TIRC7 results in significant therapeutic effects on collagen-induced arthritis in mice
Authors: Utku N , Heinemann T , Winter M , Bulwin C G , Schlawinsky M , Fraser P , Nieuwenhuis E E S , Volk H-D , Blumberg R S 
Published: March 2006

Summary
TIRC7 is a cell surface molecule which is expressed in T and B lymphocytes and negatively regulates their function. Anti-TIRC7 specific monoclonal antibody (mAb) inhibited T cell memory response to recall antigens. Up-regulation of TIRC7 on lymphocytes from joint tissue of patients with Rheumatoid Arthritis (RA) and mice with collagen induced arthritis (CIA) suggested TIRC7 as a novel target to promote anti-inflammatory reaction. Anti-TIRC7 mAb administration significantly inhibited the induction and progression of CIA and the anti-collagen IgG1 and IgG2a antibody response. Combination therapy of anti-TIRC7 mAb and soluble TNF-α receptor demonstrated an increased inhibitory effect over the single compounds on CIA. The results demonstrate the therapeutic potential of TIRC7 targeting with mAb in diseases associated with exaggerated T and B cell responses.
Cerebral leucocyte infiltration in lupus-prone MRL/MpJ-faslpr mice − roles of intercellular adhesion molecule-1 and P-selectin
Authors: James W G , Hutchinson P , Bullard D C , Hickey M J 
Published: March 2006

SummaryThe autoimmune disease which affects MRL/MpJ-faslpr mice results in cerebral leucocyte recruitment and cognitive dysfunction. We have previously observed increased leucocyte trafficking in the cerebral microcirculation of these mice; however, the types of leucocytes recruited have not been analysed thoroughly, and the roles of key endothelial adhesion molecules in recruitment of these leucocytes have not been investigated. Therefore the aim of this study was to classify the phenotypes of leucocytes present in inflamed brains of MRL/MpJ-faslpr mice, and dissect the roles of endothelial adhesion molecules in their accumulation in the brain. Immunohistochemical analysis revealed significant leucocyte infiltration in the brains of 16- and 20-week-old MRL/MpJ-faslpr mice, affecting predominantly the choroid plexus. Isolation of brain-infiltrating leucocytes revealed that lymphocytes and neutrophils were the main populations present. The CD3+ lymphocytes in the brain consisted of similar proportions of CD4+, CD8+ and CD4–/CD8–[double negative (DN)] populations. Assessment of MRL/MpJ-faslpr mice deficient in endothelial adhesion molecules intercellular adhesion molecule-1 (ICAM-1) or P-selectin indicated that cerebral leucocyte recruitment persisted in the absence of these molecules, with only minor changes in the phenotypes of infiltrating cells. Together these data indicate that the brains of MRL/MpJ-faslpr mice are affected by a mixed leucocyte infiltrate, of which the unusual DN lymphocyte phenotype contributes a substantial proportion. In addition, endothelial adhesion molecules ICAM-1 and P-selectin, which modulate survival of MRL/MpJ-faslpr mice, do not markedly inhibit leucocyte entry into the central nervous system.
The role of Fc-receptors in murine mercury-induced systemic autoimmunity
Authors: Martinsson K , Hultman P 
Published: March 2006

SummaryInorganic mercury (Hg) in genetically susceptible mouse strains induces a T cell-dependent, systemic autoimmune condition (HgIA) characterized by immunostimulation, anti-nuclear antibodies (ANA) and systemic immune-complex (IC) deposits. The exact phenotypic expression of HgIA in different strains depends on H-2 and non-H-2 genes. Fc receptors (FcRs) are important in the development of many autoimmune diseases. In this study, the effect of targeted mutations for activating and inhibiting FcRs in the BALB/c model of HgIA was examined. Hg-treated BALB/c mice without mutation (wild-type, wt) showed heavy IC deposits in the renal glomerular mesangium, as well as in renal and splenic vessel walls. The renal mesangial IC deposits were severely reduced in Hg-treated BALB/c mice without the γ-chain (lack of the activating receptors FcγRI, FcγRIII and Fc∈RI), but unchanged in mice lacking the inhibitory FcγRIIB. The Hg-induced vessel wall IC deposits present in wt mice were abolished and reduced in the FcRγ and FcγRIIB strains, respectively. Hg-treated BALB/c wt mice and mice without the γ-chain showed an increase in serum IgE, while the increase in IgG1 was attenuated in the latter strain. In contrast, absence of the inhibiting FcγRIIB augmented the Hg-induced increase of both serum IgG1 and IgE. In conclusion, FcRs are important mainly for the induction of systmeic IC deposits in the HgIA model, but also affects serum IgG1 and IgE levels.
Association of epithelial damage and signs of neutrophil mobilization in the airways during acute exacerbations of paediatric asthma
Authors: Yoshihara S , Yamada Y , Abe T , Lindén A , Arisaka O 
Published: March 2006

Summary
We examined whether epithelial damage is associated with mobilization of neutrophils or eosinophils in the airway lumen during acute exacerbations of paediatric asthma. Aspirated sputum samples were harvested from 65 paediatric patients (mean age 3·4 ± 0·4 years) during acute exacerbations of asthma. Patients with signs of infection were excluded. The presence of conglomerates of epithelial cells (i.e. ‘Creola bodies) in the aspirated sputum was utilized as a marker of epithelial damage. Among the paediatric asthma patients, 60% displayed Creola bodies (CrB+: n = 39) in their sputum samples whereas the remaining patients did not (CrB–: n = 26). CrB+ patients displayed more than a 20-fold increase in the concentration of the neutrophil-mobilizing cytokine interleukin (IL)-8 (pg/ml) and of the neutrophil product neutrophil elastase (NE, g/l), respectively, compared with CrB– patients (IL-8: 7468·2 ± 1953·6 versus 347·9 ± 72·6, P &lt; 0·01; NE: 2072·4 ± 419·0 versus 438·5 ± 125·7, P &lt; 0·01). Even though not statistically significant, a corresponding trend was observed for the relative number of sputum neutrophils. In contrast, the concentration of the eosinophil-mobilizing cytokine IL-5 and the esoinophil product ECP tended to be lower in CrB+ than in CrB– patients (P &gt; 0·05). In conclusion, as indicated by the analysis of aspirated sputum, epithelial damage is associated with a locally enhanced chemotactic signal for and activity of neutrophils, but not eosinophils, during acute exacerbations of paediatric asthma. It remains to be determined whether these indirect signs of neutrophil mobilization in the airway lumen mirror an increased number of neutrophils in the surrounding airway tissue.
Effects of haemorrhagic hypotension on the subcapsular artery and microvasculature of the rat testis
Authors: Lissbrant E. , Collin O. , Damber J‐E. , Bergh A. 
Published: March 2006

SummaryDeveloping germ cells may be sensitive to even moderate reductions in blood flow. Surprisingly, however, experimental evidence suggests that the rat testis may be unable to maintain its blood flow during a decrease in systemic blood pressure. This study was therefore performed in order to answer the following questions: Is the testis able to maintain its blood flow during moderate to major reductions in blood pressure and, if so, at which level of the testicular vasculature (main artery or microcirculation) does this compensatory response take place? Moderate (−20%) and major (−40%) reductions in blood pressure were induced in anaesthetized rats by haemorrhage and the effects on testicular microvascular blood flow and subcapsular testicular artery diameter were examined by using laser Doppler flowmetry and in vivo video‐microscopy respectively. Haemorrhagic hypotension led to decreased local testicular blood flow, but the relative reductions in flow were generally only half as large as the reductions in blood pressure. Hypotension also decreased the diameter of the main subcapsular testicular artery. During large reductions in blood pressure the subcapsular testicular artery constricts and testicular blood flow decreases. However, blood flow is reduced proportionally less than the mean arterial pressure, suggesting that local regulatory mechanisms are present in the testicular microvasculature, which may prevent blood flow from falling below a critical level.
Sexual behaviour, sperm quantity and quality after short‐term streptozotocin‐induced hyperglycaemia in rats
Authors: Scarano W. R. , Messias A. G. , Oliva S. U. , Klinefelter G. R. , Kempinas W. G. 
Published: March 2006

SummaryStudies of diabetes mellitus in the streptozotocin rat model suggest that sexual dysfunctions may result from diabetes‐induced alterations of the neuroendocrine‐reproductive tract axis. Our investigation was performed to better define the effects of short‐term hyperglycaemia on rat epididymal sperm quantity, quality and transit time, using both natural mating and artificial in utero insemination protocols. Male rats were made diabetic with streptozotocin (sc, 40 mg/kg), whereas controls received vehicle. Sexual behaviour was tested after 15 days and sperm fertilizing ability was checked 22 days after the injection through natural mating and artificial in utero insemination. Other parameters such as daily sperm production, testosterone levels, as well as sperm morphology and motility were also investigated. Fifty per cent of the diabetic animals showed no copulatory behaviour during tests and the number of animals reaching ejaculation was smaller in the diabetic group when compared with the control group (33% vs. 83%). Diabetes resulted in decreased body and reproductive organ weights, as well as diminished sperm counts in the testis and epididymis, that were associated with diminution of plasmatic testosterone levels. After natural mating, there was a decrease in the fertility in the diabetic adult male rats (25.5%) compared with control animals (81.5%). However, distal cauda epididymal sperm from diabetic rats displayed normal fertilization ability (91.5%) using in utero insemination. There were no effects of hyperglycaemia on sperm transit time in the epididymis and on spermatogenesis. Our results indicate that diabetes mellitus produces reproductive dysfunction, but does not compromise sperm fertilizing ability in the cauda epididymis in this experimental model.
Formulas for determining the dimensions of venous graft required for penile curvature correction
Authors: Hsu G.‐L. , Hsieh C.‐H. , Wen H.‐S. , Ling P.‐Y. , Chen S.‐Y. , Huang H.‐M. , Tseng G.‐F. 
Published: March 2006

SummaryTo evaluate the quantity of penile veins for use as patch material for the treatment of penile curvature, we devised two formulas: from the calculus of applied civil engineering and a diagram from the goniometry of the cadavers’ penises, respectively, and the techniques for their application. From March 1995 to July 2003, a total of 65 consecutive patients with penile curvature – 41 men with Peyronie's deformity and 24 with congenital penile deviations – underwent grafting with autologous deep dorsal veins with or without cavernosal veins as patch material. The patched veins required were calculated from the formula πr2θ/45°, which is derived from calculus. The tunical incision sector was meticulously performed in accordance with our diagram which is interpolated from seven male cadavers via goniometry and consequently the length of patched veins required was 2πrθ′/θ. The corporotomy defect was fashioned with the detubularized veins after they were adequately prepared and spliced. In these patients, the average available area of the veins was 4.9 × 2.2 cm2 (range, 4.5 × 1.8 to 5.6 × 2.4), which seemed adequate in all cases for patching, although 11 of them required two patches. Overall, 21 patients required a modified Nesbit's procedure on the contralateral/ipsilateral tunica to attain a satisfactory penile shape. Because of its anatomical vicinity and its availability as material, the deep dorsal vein associated with the cavernosal vein may play an indispensable role in grafting even with local anaesthesia on an outpatient basis.
Can lycopene be delivered into semen via prostasomes? In vitro incorporation and retention studies
Authors: Goyal A. , Delves G. H. , Chopra M. , Lwaleed B. A. , Cooper A. J. 
Published: March 2006

SummaryLycopene (C40 H56) is a highly lipophilic antioxidant found in human semen in nanomolar concentrations. It has been shown to be one of the most potent carotenoid antioxidant in various human studies. Prostasomes are organelles secreted by glandular prostatic epithelial cells and are known to play an important role in fertility and prostate cancer. They are also known to possess antioxidant activity and aid the functioning of sperm. We studied the ability of these vesicles to adsorb and retain lycopene into their rich lipid environment in vitro. High‐performance liquid chromatography analysis confirmed micrograms of lycopene per milligram of prostasomal protein. In view of the prostasomes’ lipid‐rich nature it is highly likely that these organelles act as delivery vehicles for this highly lipophilic antioxidant substance into human semen.
How to get one's voice heard: the problems of the discharge planning conference
Authors: Efraimsson Eva , Sandman Per‐Olof , Hydén Lars‐Christer , Holritz Rasmussen Birgit 
Published: March 2006

Aims.  This paper reports a study describing how patients, relatives and healthcare professionals dealt with the variety of problems and responsibilities that occur in discharge planning conferences and especially how they managed to do this given the institutional frame that surrounded the meeting.Background.  In Sweden, the aim of a discharge planning conference is to co‐ordinate social and healthcare resources as patients are discharged from hospitals. Patients, relatives and hospital staff, along with healthcare professionals responsible for outpatient care, assemble to achieve an individual care plan. One of the explicit principles informing the discharge planning conference is to increase patients’ influence on decision‐making. However, research points at shortcomings in this respect.Method.  A discourse analysis was conducted using transcriptions of eight video‐recorded discharge planning conferences. The selected patients were eight older women expected to be discharged from hospital. Other participants were staff nurses, social workers and occasionally relatives, an occupational therapist, district nurse or home care aide.Findings.  Participants adopted different roles as persons/patients, relative/next of kin and healthcare professionals/institutional representatives during the discharge planning conference, which they simultaneously struggled to act upon. The findings are presented under the categories ‘Clashing roles and perspectives’ and ‘Facing the institutional frame’.Conclusions.  The performance of the discharge planning conference in its present form interferes with a caring perspective that protects patients’ integrity and gives prominence to their life worlds. Moreover, it does not satisfy patients’ and relatives’ right to expect proceedings that enhance their possibility to express their personal wishes in a dignified manner.
A theory for the nursing care of patients at risk of suicide
Authors: Sun Fan‐Ko , Long Ann , Boore Jennifer , Tsao Lee‐Ing 
Published: March 2006

Aim.  This paper presents a nursing care theory developed to guide the care given to people with suicidal ideas and those with a previous suicide attempt.Background.  Suicide is a major public health problem. According to the World Health Organization, international suicide rates range from highs of more than 20 per 100 000 people in Hungary (1997 figures), to fewer than 10 per 100 000 in the United Kingdom (2002 figures). In 2002, the number of completed suicides in Taiwan increased by nearly 10% over the previous year, and the Taiwanese Government has set targets to reduce this rate. Psychiatric nurses play a vital role in helping reduce the suicide rate through prevention, education and by providing care that promotes the healing of patients who attempt suicide.Methods.  A grounded theory approach was used. Fifteen patients who had either suicidal ideas or had attempted suicide and 15 psychiatric nurses working on acute wards were interviewed and observed using an observer‐as‐participant strategy. Data were collected through field notes and by tape‐recorded interviews during 2003, and analysed using open, axial and selective coding and the qualitative software program QRS NUD*IST.Findings.  The core category that emerged from the data collected was the provision of ‘safe and compassionate care via the channel of the therapeutic relationship’. Other key categories linked to and embraced within this core category were: providing holistic assessments; providing protection; providing basic care; and promoting healing through advanced care.Conclusion.  The theory generated from the findings could be used by nurses as a guide as they initiate and maintain therapeutic relationships with patients who are at risk of suicide. The theory could advance the quality of care provided by nurses. In addition, it holds potential for instilling hope in patients who have lost their ability to cope with life events and perhaps life itself.