bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevalence and predictors of tuberculin skin positivity in Hellenic Army recruits
Authors: German Vasilios , Giannakos Georgios , Kopterides Petros , Falagas Matthew E
Published: June 2006

Background

Tuberculosis (TB) remains one of the leading causes of death among infectious diseases worldwide. Despite its low incidence rates in countries of Western Europe and North America, the resurgence of TB in Eastern Europe and the increased immigration from high-incidence countries imply that extreme vigilance is required in order to detect early, treat, and isolate all new cases. In this study, we analyzed the prevalence and predictors of tuberculin skin testing positivity in Hellenic Army recruits.

Methods

The study population consisted of 953 Greek military recruits enlisted inthe Army during the period from November 2005 toFebruary 2006. Tuberculin skin testing was performed on all study subjects upon enrollment, according to the routine procedures. A tuberculin skin test reaction size >15 mm was considered positive for all study participants. Epidemiological data regarding age, repatriation status, geographic area of residence, smoking habits, and parental occupation were collected by means of personal interviews. In addition, body weight, height, and body mass index were measured.

Results

The mean age of the studied subjects (± SD) was 23.5 (± 6.4) years. The overall prevalence of tuberculin positivity was 3.9% (37/953), and bivariable analysis showed that it was associated with lower weight (p = 0.047) and repatriation status (p < 0.001). Tuberculin skin testing was positive in 2.6% of natives (24/900) and 24.5% of repatriates (13/53). A backward, stepwise multivariable logistic regression model showed that only repatriation status was independently associated with tuberculin positivity (p < 0.001; odds ratio [OR]: 14.1; 95% confidence interval [CI]: 6.5–30.3).

Conclusion

While the incidence of tuberculosis in the native Greek population is low, and comparable to other Western European countries, the extremely high tuberculin positivity in repatriated persons underscores the importance of actively screening for TB in order to promptly identify, isolate, and treat cases of active and latent infection.
How much time do health services spend on antenatal care? Implications for the introduction of the focused antenatal care model in Tanzania
Authors: von Both Claudia , Fleβa Steffen , Makuwani Ahmad , Mpembeni Rose , Jahn Albrecht
Published: June 2006

Background

Antenatal care (ANC) is a widely used strategy to improve the health of pregnant women and to encourage skilled care during childbirth. In 2002, the Ministry of Health of the United Republic of Tanzania developed a national adaptation plan based on the new model of the World Health Organisation (WHO). In this study we assess the time health workers currently spent on providing ANC services and compare it to the requirements anticipated for the new ANC model in order to identify the implications of Focused ANC on health care providers' workload.

Methods

Health workers in four dispensaries in Mtwara Urban District, Southern Tanzania, were observed while providing routine ANC. The time used for the overall activity as well as for the different, specific components of 71 ANC service provisions was measured in detail; 28 of these were first visits and 43 revisits. Standard time requirements for the provision of focused ANC were assessed through simulated consultations based on the new guidelines.

Results

The average time health workers currently spend for providing ANC service to a first visit client was found to be 15 minutes; the provision of ANC according to the focused ANC model was assessed to be 46 minutes. For a revisiting client the difference between current practise and the anticipated standard of the new model was 27 minutes (9 vs. 36 min.). The major discrepancy between the two procedures was related to counselling. On average a first visit client was counselled for 1:30 minutes, while counselling in revisiting clients did hardly take place at all. The simulation of focused ANC revealed that proper counselling would take about 15 minutes per visit.

Conclusion

While the introduction of focused ANC has the potential to improve the health of pregnant women and to raise the number of births attended by skilled staff in Tanzania, it may need additional investment in human resources. The generally anticipated saving effect of the new model through the reduction of routine consultations may not materialise because the number of consultations is already low in Tanzania with a median of only 4 visits per pregnancy. Special attention needs to be given to counselling attitudes and skills during the training for Focused ANC as this component is identified as the major difference between old practise and the new model. Our estimated requirement of 46 minutes per first visit consultation matches well with the WHO estimate of 40 minutes.
TUCAN/CARDINAL/CARD8 and apoptosis resistance in non-small cell lung cancer cells
Authors: Checinska Agnieszka , Giaccone Giuseppe , Hoogeland Bas SJ , Ferreira Carlos G , Rodriguez Jose A , Kruyt Frank AE
Published: June 2006

Background

Activation of caspase-9 in response to treatment with cytotoxic drugs is inhibited in NSCLC cells, which may contribute to the clinical resistance to chemotherapy shown in this type of tumor. The aim of the present study was to investigate the mechanism of caspase-9 inhibition, with a focus on a possible role of TUCAN as caspase-9 inhibitor and a determinant of chemosensitivity in NSCLC cells.

Methods

Caspase-9 processing and activation were investigated by Western blot and by measuring the cleavage of the fluorogenic substrate LEHD-AFC. Proteins interaction assays, and RNA interference in combination with cell viability and apoptosis assays were used to investigate the involvement of TUCAN in inhibition of caspase-9 and chemosensitivity NSCLC.

Results

Analysis of the components of the caspase-9 activation pathway in a panel of NSCLC and SCLC cells revealed no intrinsic defects. In fact, exogenously added cytochrome c and dATP triggered procaspase-9 cleavage and activation in lung cancer cell lysates, suggesting the presence of an inhibitor. The reported inhibitor of caspase-9, TUCAN, was exclusively expressed in NSCLC cells. However, interactions between TUCAN and procaspase-9 could not be demonstrated by any of the assays used. Furthermore, RNA interference-mediated down-regulation of TUCAN did not restore cisplatin-induced caspase-9 activation or affect cisplatin sensitivity in NSCLC cells.

Conclusion

These results indicate that procaspase-9 is functional and can undergo activation and full processing in lung cancer cell extracts in the presence of additional cytochrome c/dATP. However, the inhibitory protein TUCAN does not play a role in inhibition of procaspase-9 and in determining the sensitivity to cisplatin in NSCLC.
Randomised controlled trial of welfare rights advice accessed via primary health care: pilot study [ISRCTN61522618]
Authors: Mackintosh Joan , White Martin , Howel Denise , Chadwick Tom , Moffatt Suzanne , Deverill Mark , Sandell Adam
Published: June 2006

Background

Little research has directly evaluated the impact of increasing financial or material resources on health. One way of assessing this lies with assisting people to obtain full welfare benefit entitlements. In 2000–1, 2.3 million pensioners were living in poverty in the UK and estimates suggest that around one million do not claim the financial support to which they are entitled. The effectiveness of welfare rights advice services delivered via primary health care to promote health and reduce health inequalities is unknown.

Methods

The main objectives of this study were to assess the feasibility and acceptability of a randomised controlled trial of welfare rights advice in a community setting and identify appropriate health and social outcome measures in order to plan a definitive trial.

This was a single blind, community-based, pilot randomised controlled trial. 126 men and women aged 60 years and over, recruited from 4 general practices in Newcastle upon Tyne, UK, participated. The intervention comprised a structured welfare rights assessment followed by active assistance with welfare benefit claims over the following 24 months. The control group received the intervention after a six month delay. A range of socio-economic, health, behavioural and psycho-social outcomes were measured.

Results

126 out of 400 people invited agreed to participate and 109 were followed up at 24 months. Both the intervention and research procedures were feasible and acceptable to participants and professionals involved. 68 (58%) of all participants received a welfare benefit award (31 financial, 16 non-financial and 21 both). Median time to receipt of benefits from initial assessment was 14 (range 1 to 78) weeks and median financial award was £55 (€81, $98) per household per week. There was little evidence of health-related differences between groups or over time, which could be due to limitations of the study design.

Conclusion

Modification of the study design, including selection of study participants, timing of interventions and length of follow up are recommended for a definitive trial. More appropriate health and psycho-social outcome measures relevant to the elderly population should be sought, particularly focussing on those issues highlighted in the accompanying qualitative study.
Antimicrobial and toxicological evaluation of the leaves of Baissea axillaries Hua used in the management of HIV/AIDS patients
Authors: Abere Tavs A , Agoreyo Freddy O
Published: June 2006

Background

Persistent diarrhea is a common endemic disease with high incidence among the Africans including Nigerians. It also represents a frequent opportunistic disease in people living with HIV. Diarrhea represents one of the most distressful and persistent symptoms of HIV/AIDS, which may or may not be accompanied by an infection. The leaves decoction of Baissea axillaries Hua (Apocynaceae) is used by traditional herbalists in Edo state, Nigeria for the management of people living with HIV/AIDS. Determination of its antimicrobial activity and toxicological profile will provide supportive scientific evidence in favour of its continuous usage.

Method

Chemical and chromatographic tests were employed in phytochemical investigations. Inhibitory activities of aqueous and ethanolic extracts against clinical strains of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus faecalis were compared with Togamycin (Spectinomycin). Our report includes minimum inhibitory concentration (MIC) against the test organisms. Toxicological evaluation was determined by administering 250 mg/kg and 500 mg/kg of extracts on male Wister rats for 14 days with normal saline as control. The kidneys, liver, heart and testis tissues were examined.

Results

Phytochemical studies revealed the presence of alkaloids, tannins, and cyanogenetic glycosides. The extracts inhibited the growth of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus to varying extents, but only the ethanolic extract inhibited growth in Streptococcus faecalis. The LD50 of the extract in mice was above 5000 mg/kg body weight when administered intraperitoneally. Toxicological evaluation showed mere ballooning degeneration of the liver at 250 mg/kg while at 500 mg/kg there was tissue necrosis. The low and high doses showed ill-defined leydig cells in the testis and no remarkable changes in the heart and kidneys.

Conclusion

Extracts of Baissea axillaries have demonstrated antimicrobial activity against clinical strains of selected microorganisms. While there is toxicity at the dose of 500 mg/kg, the therapy shows potential for application in the treatment of diarrhoea associated with AIDS/HIV. Further studies of Baissea axillaries on diarrhoea and toxicity are necessary to evaluate its mechanism of action and to fully establish its safety profile.
Mode of inhibition of HIV-1 Integrase by a C-terminal domain-specific monoclonal antibody*
Authors: Ramcharan Joseph , Colleluori Diana M , Merkel George , Andrake Mark D , Skalka Anna Marie
Published: June 2006

Background

To further our understanding of the structure and function of HIV-1 integrase (IN) we developed and characterized a library of monoclonal antibodies (mAbs) directed against this protein. One of these antibodies, mAb33, which is specific for the C-terminal domain, was found to inhibit HIV-1 IN processing activityin vitro; a corresponding Fv fragment was able to inhibit HIV-1 integrationin vivo. Our subsequent studies, using heteronuclear nuclear magnetic resonance spectroscopy, identified six solvent accessible residues on the surface of the C-terminal domain that were immobilized upon binding of the antibody, which were proposed to comprise the epitope. Here we test this hypothesis by measuring the affinity of mAb33 to HIV-1 proteins that contain Ala substitutions in each of these positions. To gain additional insight into the mode of inhibition we also measured the DNA binding capacity and enzymatic activities of the Ala substituted proteins.

Results

We found that Ala substitution of any one of five of the putative epitope residues, F223, R224, Y226, I267, and I268, caused a decrease in the affinity of the mAb33 for HIV-1 IN, confirming the prediction from NMR data. Although IN derivatives with Ala substitutions in or near the mAb33 epitope exhibited decreased enzymatic activity, none of the epitope substitutions compromised DNA binding to full length HIV-1 IN, as measured by surface plasmon resonance spectroscopy. Two of these derivatives, IN (I276A) and IN (I267A/I268A), exhibited both increased DNA binding affinity and uncharacteristic dissociation kinetics; these proteins also exhibited non-specific nuclease activity. Results from these investigations are discussed in the context of current models for how the C-terminal domain interacts with substrate DNA.

Conclusion

It is unlikely that inhibition of HIV-1 IN activity by mAb33 is caused by direct interaction with residues that are essential for substrate binding. Rather our findings are most consistent with a model whereby mAb33 binding distorts or constrains the structure of the C-terminal domain and/or blocks substrate binding indirectly. The DNA binding properties and non-specific nuclease activity of the I267A derivatives suggest that the C-terminal domain of IN normally plays an important role in aligning the viral DNA end for proper processing.
Tumour necrosis factor-α stimulates HIV-1 replication in single-cycle infection of human term placental villi fragments in a time, viral dose and envelope dependent manner
Authors: Kfutwah Anfumbom KW , Mary Jean-Yves , Nicola Marie-Anne , Blaise-Boisseau Sandra , Barré-Sinoussi Françoise , Ayouba Ahidjo , Menu Elisabeth
Published: June 2006

Background

The placenta plays an important role in the control ofin uteroHIV-1 mother-to-child transmission (MTCT). Proinflammatory cytokines in the placental environment are particularly implicated in this control. We thus investigated the effect of TNF-α on HIV-1 expression in human placental tissuesin vitro.

Results

Human placental chorionic villi fragments were infected with varying doses of luciferase reporter HIV-1 pseudotypes with the R5, X4-Env or the vesicular stomatitis virus protein G (VSV-G). Histocultures were then performed in the presence or absence of recombinant human TNF-α. Luciferase activity was measured at different time points in cell lysates or on whole fragments usingex vivoimaging systems.

A significant increase in viral expression was detected in placental fragments infected with 0.2 ng of p24 antigen/fragment (P = 0.002) of VSV-G pseudotyped HIV-1 in the presence of TNF-α seen after 120 hours of culture. A time independent significant increase of viral expression by TNF-α was observed with higher doses of VSV-G pseudotyped HIV-1. When placental fragments were infected with R5-Env pseudotyped HIV-1, a low level of HIV expression at 168 hours of culture was detected for 3 of the 5 placentas tested, with no statistically significant enhancement by TNF-α. Infection with X4-Env pseudotyped HIV-1 did not lead to any detectable luciferase activity at any time point in the absence or in the presence of TNF-α.

Conclusion

TNF-α in the placental environment increases HIV-1 expression and could facilitate MTCT of HIV-1, particularly in an inflammatory context.
Trimellitic anhydride-conjugated serum albumin activates rat alveolar macrophages in vitro
Authors: Valstar Dingena L , Schijf Marcel A , Stelekati Erietta , Nijkamp Frans P , Bloksma Nanne , Henricks Paul AJ
Published: June 2006

Background

Occupational exposure to airborne low molecular weight chemicals, like trimellitic anhydride (TMA), can result in occupational asthma. Alveolar macrophages (AMs) are among the first cells to encounter these inhaled compounds and were previously shown to influence TMA-induced asthma-like symptoms in the Brown Norway rat. TMA is a hapten that will bind to endogenous proteins upon entrance of the body. Therefore, in the present study we determined if TMA and TMA conjugated to serum albumin induced the production of the macrophage mediators nitric oxide (NO), tumour necrosis factor (TNF), and interleukin 6 (IL-6)in vitrousing the rat AM cell line NR8383 and primary AMs derived from TMA-sensitized and naïve Brown Norway rats.

Methods

Cells were incubated with different concentrations of TMA, TMA conjugated to bovine serum albumin (BSA), and BSA as a control for 24 h and the culture supernatant was analyzed for mediator content.

Results

TMA alone was not able to induce the production of mediators by NR8383 cells and primary AMs from sensitized and sham-treated rats. TMA-BSA, on the contrary, dose-dependently stimulated the production of NO, TNF, and IL-6 by NR8383 cells and of NO and TNF, but not IL-6, by primary AMs independent of sensitization.

Conclusion

Results suggest that although TMA is a highly reactive compound, conjugation to a suitable protein is necessary to induce mediator production by AMs. Furthermore, the observation that effects of TMA-BSA were independent of sensitization suggests involvement of an immunologically non-specific receptor. In the discussion it is argued that a macrophage scavenger receptor is a likely candidate.
Neutrophil apoptosis in rheumatoid arthritis is regulated by local oxygen tensions within joints
Authors: Cross Andrew , Barnes Theresa , Bucknall Roger C , Edwards Steven W , Moots Robert J
Published: June 2006

Neutrophils are normally short-lived cells and die by apoptosis, but when recruited into tissues, their apoptosis is delayed, and they survive for much longer time periods. In inflammatory diseases, such as rheumatoid arthritis (RA), this delayed apoptosis may lead to increased tissue damage and a failure of the inflammation to resolve. However, there are conflicting reports in the literature as to whether neutrophil apoptosis is delayed or accelerated in rheumatoid joints. In this report, we show that neutrophils isolated from the ynovial fluid (SF) of patients with RA show accelerated rates of apoptosis when incubated ex vivo and that SF, despite containing a variety of antiapoptotic cytokines, is proapoptotic. Paradoxically, levels of the key neutrophil survival protein Mcl-1 are elevated in freshly isolated SF neutrophils compared with matched peripheral blood samples from the same patients, indicating that delayed neutrophil apoptosis has been signaled in vivo as the cells enter the joints. However, when SF was added to neutrophils and incubated under hypoxia (1% O2), conditions known to exist in vivo within joints, the SF was antiapoptotic. These data reveal that the rheumatoid synovial joint contains a complex mixture of pro- and antiapoptotic factors and that the low, local oxygen tensions that exist within these joints can exert profound effects on neutrophil survival. These experiments also highlight the importance of performing in vitro experiments under laboratory conditions that closely mimic those that occur in vivo; otherwise, misleading conclusions may be drawn.
Inflammatory processes triggered by TCR engagement or by local cytokine expression: differences in profiles of gene expression and infiltrating cell populations
Authors: Takase Hiroshi , Yu Cheng-Rong , Ham Don-Il , Chan Chi-Chao , Chen Jun , Vistica Barbara P , Wawrousek Eric F , Durum Scott K , Egwuagu Charles E , Gery Igal
Published: June 2006

Immune cell-mediated inflammatory responses are triggered by TCR engagement with the target antigen, the initial event that brings about the complex sequence of events of the inflammatory process. Another form of inflammation is induced by local expression of certain cytokines. Unlike the former form of inflammation, little is known about the basic features of the cytokine-induced responses. Here, we analyzed tissue morphology, the infiltrating cells, and up-regulated, inflammation-related genes in mouse eyes in which inflammation is triggered by local transgenic (Tg) expression of cytokines and compared these features with those in eyes with experimental autoimmune uveitis (EAU), in which inflammation is initiated by engagement of TCR on sensitized T cells with their target antigen, followed by the well-defined, subsequent cytokine production. Eyes of IFN-γ Tg mice exhibited severe, morphological changes but essentially no inflammation, and intense inflammation was found in eyes of interleukin (IL)-1 or IL-7 Tg mice. The cellular infiltration in eyes of these latter two lines of Tg mice resembled that in eyes with EAU by including many CD4 cells, but unlike in EAU, the infiltration in Tg eyes contained large proportions of B cells and only small numbers of macrophages. Real-time PCR analysis of eye RNA revealed differences among the disease models in the expression profiles of various inflammation-related genes. It is interesting that a bias toward T helper cell type 1 immunity (high IFN-γ, RANTES/CCL5, MIG/CXCL9, and T-bet but low IL-4, IL-5, and GATA-3 transcripts) was found in EAU eyes but not in eyes of IL-1 and IL-7 Tg mice. The results thus show that similar to TCR engagement, local expression of certain cytokines triggers a complex, subsequent production of numerous inflammation-related molecules, but features of the ensued inflammatory process are determined by the triggering mechanism.
Biological Properties of a Novel Follicle-Stimulating Hormone/Human Chorionic Gonadotropin Chimeric Gonadotropin
Authors: Garone Louise M. , Ammannati Elena , Brush Theresa S. , Fischer David J. , Tos Enrico Gillio , Luo Jiangping , Altobello Kimberley L. , Ciampolillo Cinzia , Ihley Thomas M. , Kurosawa Emmi , Tiebout Angela , McKenna Sean
Published: June 2006

A chimeric recombinant human gonadotropin, termed C3, demonstrates both follitropic and lutropic bioactivities. The α-subunit construct for C3 is comprised of the recombinant wild-type human glycoprotein hormone α-subunit. The β-subunit DNA construct for C3 encodes residues 1–145 from human chorionic gonadotropin (hCG)-β with the exceptions that FSHβ amino acid 88 (D) is substituted for hCGβ amino acid 94 (R) and FSHβ amino acids 95–108 (TVRGLGPSYCSFGE) are substituted for hCGβ amino acids 101–114 (GGPKDHPLTCDDPR). C3 is a potent FSH and LH agonist able to bind and to signal through FSH and LH receptors in vitro. In in vivo bioassays optimized to quantify each type of activity, C3 was found to have lutropin and follitropin potencies at levels similar to those of recombinant human LH and recombinant human FSH, respectively. In immature rats, C3 was sufficient to support the maturation of normal ovarian follicles. Moreover, a significant portion of follicles matured by C3 ruptured in response to an ovulatory hCG stimulus and gave rise to morphologically normal oocytes. Furthermore, a low dose of C3 promoted weight gain in the rodent uterus, suggesting it also supported preparation for implantation without histological evidence of excessive luteinization of the ovary. In summary, the biological properties of C3 indicate that its chimeric nature has resulted in a fully functional, dual-acting human gonadotropin.
Cortisol Production Rate in Posttraumatic Stress Disorder
Authors: Wheler G. H. Trevor , Brandon David , Clemons Aaron , Riley Crystal , Kendall John , Loriaux D. Lynn , Kinzie J. David
Published: June 2006

Context: Several authors have reported the unsuspected finding of low cortisol levels (urinary, salivary, and serum) in patients with posttraumatic stress disorder (PTSD).

Objective: Our objective was to assess concentrations of cortisol and its predominant metabolites, cortisol production rate (CPR), and glucocorticoid receptor (GR) binding characteristics in PTSD compared with normal subjects.

Design: Matched PTSD patients and control subjects had CPR determined by a stable isotope dilution technique after infusion of deuterated cortisol. Serum cortisol, urinary cortisol, and its metabolites were measured by gas chromatography/mass spectrometry. GR binding capacity (Ro) and ligand binding affinity (Kd) were measured in mononuclear leukocytes.

Setting: All subjects were tested during a 40-h admission in an inpatient clinical research center.

Patients and Participants: Ten patients with PTSD were matched by age and gender with 10 controls.

Outcome Measures: Statistical comparison was conducted for various measures of cortisol in PTSD patients and normal subjects.

Results: No statistical difference was found in mean level or circadian pattern of cortisol secretion using serum or salivary immunoassay detection methods. Although in the normal range, urinary cortisol by immunoassay showed statistically lower values over a 24-h period in PTSD patients compared with controls. This finding was not confirmed by gas chromatography/mass spectrometry determination of cortisol or its metabolites. CPR was not statistically different between these groups. GR also showed no alteration in Ro or Kd between the groups.

Conclusion: The data indicate that PTSD in the chronic and unprovoked state is not characterized by an acute biological stress response.
Systematic analysis of myotubularins: heteromeric interactions, subcellular localisation and endosomerelated functions
Authors: Lorenzo Óscar , Urbé Sylvie , Clague Michael J.
Published: June 2006

The myotubularins are a large family of lipid phosphatases with specificity towards PtdIns3P and PtdIns(3,5)P2. Each of the 14 family members bears a signature phosphatase domain, which is inactive in six cases due to amino acid changes at the catalytic site. Fragmentary data have indicated heteromeric interactions between myotubularins, which have hitherto paired an active family member with an inactive one. In this study we have conducted a largescale analysis of potential associations within the human myotubularin family, through directed two-hybrid screening and immunoprecipitation of epitope-tagged proteins. We have confirmed all previously reported combinations and identified novel heteromeric interactions: MTMR8 with MTMR9, and MTMR3 with MTMR4, the first such combination of enzymatically active MTMs. We also report the capacity of several family members to self-associate, including MTMR3 and MTMR4. Subcellular localisation studies reveal a unique distribution of MTMR4 to endosomal structures, the major site of substrate lipid accumulation. All active MTMs we have tested (MTM1, MTMR2-MTMR4) reduce endosomal PtdIns3P levels upon overexpression. Despite this, only MTMR4 exerts any effect on EGF receptor trafficking and degradation, which is more pronounced with a phosphatase inactive form of MTMR4 and requires an intact FYVE domain.
A Convenient Route to β,γ-Unsaturated Esters without Formation of the α,β-Isomers. Palladium-Catalyzed Alkoxycarbonylation of Allylic Halides under Alcohol–Potassium Carbonate Tow-Phase Conditions
Authors: Kiji Jitsuo , Okano Tamon , Higashimae Yukiko , Fukui Yasuyuki
Published: June 2006

Palladium-catalyzed, atmospheric pressure carbonylation of allylic halides under alcohol-potassium carbonate (liquid–solid) two-phase conditions affords β,γ-unsaturated esters without formation of the α,β-isomers. Phosphine-free palladium compounds such as Pd(OAc)2 (1) and Na2[PdCl4] (2) are a convenient catalyst for this reaction. Presence of triphenylphosphine retards the carbonylation. A mixture of Pd(OAc)2-PPh3 or [PdCl2(PPh3)2] (3) catalyzes the carbonylation under pressure.
Thermodynamic and Kinetic Studies of Zinc(II)–Triamine Complexes as Models of CA and AP
Authors: Itoh Toyofumi , Fujii Yuki , Tada Toshiji , Yoshikawa Yuzo , Hisada Hiroyuki
Published: June 2006

The formation constant (KZnL), enthalpy and entropy changes (ΔH and ΔS), and deprotonation constant (Ka) of coordinated water for hydrated zinc(II)–triamine (1 : 1) complexes (N3–Zn-(OH2)n (N3 = diethylenetriamine (dien), N-(2-aminoethyl)-1,3-propanediamine (epd), dipropylenetriamine (dpt), cis,cis-1,3,5-triaminocyclohexane (tach), and 1,5,9-triazacyclododecane ([12]aneN3)) were determined by potentiometry. The pKa linearly increased along with an increase in -ΔH, and was explained in terms of a ligand–ligand interaction through the N3–Zn-O bond on the bases of a thermodynamic analysis and strain-energy calculation (MM2). The zinc(II) complex-promoted hydrolysis of 2,4-dinitrophenyl diethyl phosphate was investigated in 1% (v/v) methanol–water; the rate constants linearly increased along with decreases of pKa and −ΔH. This fact indicates that the hydrolysis proceeds via a concerted direct nucleophilic attacking mechanism of the coordinated hydroxide ion, in which the phosphate ester coordinates to the zinc(II) ion. X-ray structure analyses for synthesized model complexes, [Zn(OAc)(dien)](ClO4), [{Zn(dpt)}3(CO3)](ClO4)4·NaClO4, and [Zn(OAc)(tach)](ClO4), are also reported.
Geometrical Isomerism of the Exocyclic C=C Bonds of Heptafulvene Derivatives. Steric and Electronic Effects on the Rotational Barrier
Authors: Ikeda Yukari , Yin Bing Zhu , Kato Nobuo , Mori Akira , Takeshita Hitoshi
Published: June 2006

The rotational barriers of the exocyclic double bonds of a series of methyl 8-cyanoheptafulvene-8-carboxylates were measured to evaluate the steric effect and the contribution of the polarized structures. An incorporation of five-membered heterocycles lowered the activation energies sufficiently to allow the study of steric and electronic factors. Thus, the Type I compounds, 8-[cyano(methoxycarbonyl)methylidene]-2-methyl-8H-cyclohepta[b]furan and its sulfur and nitrogen analogues, which have a different extent of steric effect, had rates of rotation in the order of N > S > O. On the other hand, the Type II derivatives, 6-(1-cyano-1-methoxycarbonylmethylidene)-2-methylcyclohepta[b]furan and its sulfur and nitrogen analogues, for which the steric factor is unimportant, showed an order of N > O > S. This was also the case for the Type III derivatives, methyl 8-cyano-3-methoxyheptafulvene-8-carboxylate, methyl 8-cyano-3-(methylthio)heptafulvene-8-carboxylate, and methyl 8-cyano-3-(dimethylamino)heptafulvene-8-carboxylate. The unusually low values of ΔH‡ for the nitrogen analogues indicated that the ground state structures were destabilized by the steric repulsions.
Theoretical Study on Metal NMR Chemical Shifts. Electronic Mechanism of the Xe Chemical Shift
Authors: Tanaka Shinji , Sugimoto Manabu , Takashima Hajime , Hada Masahiko , Nakatsuji Hiroshi
Published: June 2006

The 129Xe chemical shifts of the complexes XeF2n, XeF2n−1+ and XeOnF6−2n (n = 1—3) are studied theoretically by ab initio finite perturbation method. The first-order higher basis functions (FOBFs) are added to the standard basis set for removing the gauge-dependence. The calculated values of the Xe chemical shifts agree reasonably with the experimental values. Though the electronic configuration of Xe is the closed shell 5s25p6, the electronic mechanism of the Xe chemical shift is shown to be the p-mechanism. Namely, the dominant term in the Xe chemical shift is the paramagnetic term and it is mainly governed by the Xe valence p AO contribution. Actually, as expected, the Xe chemical shifts show the U-shaped dependence on the number of the Xe valence p electrons. The diamagnetic term is small and depends linearly on the number of the ligands.
Cationic Phosphenium Complexes of Group 6 Transition Metals. Systematic Approach to Elucidation of Influence of Substituents of the Phosphenium Phosphorus on the Stability of the Complexes
Authors: Yamaguchi Yoshitaka , Nakazawa Hiroshi , Itoh Tomonori , Miyoshi Katsuhiko
Published: June 2006

Group 6 transition-metal phosphite complexes, fac-[(bpy)(CO)3M{PXY(OMe)}] (M = Cr, Mo, and W; XY = (NEt2)2, 1a; N(Me)CH2CH2O, 2a; (NEt2)(OMe), 3a; OCMe2CMe2O, 4a; (OMe)2, 5a) have been prepared and subjected to the reaction with BF3·OEt2. In these reactions, cationic phosphenium complexes [(bpy)(CO)3M{PXY}]+ are formed by an OMe abstraction as an anion from the phosphorus ligand for 1a, 2a, and 3a (M = Mo, W). The reaction of 3a (M = Cr) yields fac-[(bpy)(CO)3Cr{P(OMe)2F}] (Cr-5c) and [(bpy)(CO)3Cr{P(NEt2)F2}] (Cr-7d). In the reaction of 4a and 5a for all group 6 congeners, an OMe/F substitution reaction takes place to give and fac-[(bpy)(CO)3M{P(OMe)2F}]. These results reveal that the stability of cationic phosphenium complexes increases with (i) going to a heavier congener, (ii) increasing the number of amino substituents on the phosphenium phosphorus, and (iii) adding an ethylene bridge between X and Y when at least one of X and Y is an amino substituent.
Dynamic Mixed Duopoly: A Model Motivated by Linux vs. Windows
Authors: Casadesus-Masanell Ramon , Ghemawat Pankaj
Published: June 2006

This paper analyzes a dynamic mixed duopoly in which a profit-maximizing competitor interacts with a competitor that prices at zero (or marginal cost), with the cumulation of output affecting their relative positions over time. The modeling effort is motivated by interactions between Linux, an open source operating system, and Microsoft’s Windows and consequently emphasizes demand-side learning effects that generate dynamic scale economies (or network externalities). Analytical characterizations of the equilibrium under such conditions are offered, and some comparative static and welfare effects are examined.
Exploring the Structure of Complex Software Designs: An Empirical Study of Open Source and Proprietary Code
Authors: MacCormack Alan , Rusnak John , Baldwin Carliss Y.
Published: June 2006

This paper reports data from a study that seeks to characterize the differences in design structure between complex software products. We use design structure matrices (DSMs) to map dependencies between the elements of a design and define metrics that allow us to compare the structures of different designs. We use these metrics to compare the architectures of two software products—the Linux operating system and the Mozilla Web browser—that were developed via contrasting modes of organization: specifically, open source versus proprietary development. We then track the evolution of Mozilla, paying attention to a purposeful “redesign” effort undertaken with the intention of making the product more “modular.” We find significant differences in structure between Linux and the first version of Mozilla, suggesting that Linux had a more modular architecture. Yet we also find that the redesign of Mozilla resulted in an architecture that was significantly more modular than that of its predecessor and, indeed, than that of Linux. Our results, while exploratory, are consistent with a view that different modes of organization are associated with designs that possess different structures. However, they also suggest that purposeful managerial actions can have a significant impact in adapting a design’s structure. This latter result is important given recent moves to release proprietary software into the public domain. These moves are likely to fail unless the product possesses an “architecture for participation.”
The Promise of Research on Open Source Software
Authors: von Krogh Georg , von Hippel Eric
Published: June 2006

Breaking with many established assumptions about how innovation ought to work, open source software projects offer eye-opening examples of novel innovation practices for students and practitioners in many fields. In this article we briefly review existing research on the open source phenomenon and discuss the utility of open source software research findings for many other fields. We categorize the research into three areas: motivations of open source software contributors; governance, organization, and the process of innovation in open source software projects; and competitive dynamics enforced by open source software. We introduce the articles in this special issue of Management Science on open source software, and show how each contributes insights to one or more of these areas.
Urinary excretion of deoxypyridinoline in Perthes’ disease
Authors: Westhoff B. , Krauspe R. , Kalke A. E. , Hermsen D. , Kowall B. , Willers R. , Schneider U.
Published: June 2006

Our aim was to investigate the relationship between urinary excretion of deoxypyridinoline (DPD) as a marker of bone resorption, and Perthes’ disease. There were 39 children with Perthes’ disease in the florid stage who collected first-morning urine samples at regular intervals of at least three months. The level of urinary DPD was analysed by chemiluminescence immunoassay and was correlated with the radiological stage of the disease as classified by Waldenström, and the severity of epiphyseal involvement according to the classification systems of Catterall and Herring. The urinary DPD levels of a group of 44 healthy children were used as a control.

The median urinary DPD/creatinine (CREA) ratio was significantly reduced (p < 0.0001) in the condensation stage and increased to slightly elevated values at the final stage (p = 0.05) when compared with that of the control group. Herring-C patients showed significantly lower median DPD/CREA ratios than Herring-B patients (p = 0.03). The significantly decreased median DPD/CREA ratio in early Perthes’ disease indicated a reduced bone turnover and supports the theory of a systemic aetiology. Urinary levels of DPD may therefore be used to monitor the course of Perthes’ disease.
Internal fixation of undisplaced lesions of osteochondritis dissecans in the knee
Authors: Din R. , Annear P. , Scaddan J.
Published: June 2006

A total of 11 patients (12 knees) with stable lesions of osteochondritis dissecans of the knee underwent arthroscopic fixation of the fragments using polylactide bioabsorbable pins. The site of the lesion was the medial femoral condyle in ten knees and the lateral femoral condyle in two. The mean age of the patients was 14.8 years (12 to 16). At a mean follow-up of 32.4 months (13 to 38 months) all fragments had MRI evidence of union. One patient developed early transient synovitis, which resolved with non-steroidal anti-inflammatory medication. All patients returned to sporting activities within eight months of operation and did not require a period of immobilisation.
Acetabular reconstruction with impacted bone allografts and cemented acetabular components
Authors: Comba F. , Buttaro M. , Pusso R. , Piccaluga F.
Published: June 2006

We reviewed the clinical and radiological results of 131 patients who underwent acetabular revision for aseptic loosening with impacted bone allograft and a cemented acetabular component. The mean follow-up was 51.7 months (24 to 156).

The mean post-operative Merle D’Aubigné and Postel scores were 5.7 points (4 to 6) for pain, 5.2 (3 to 6) for gait and 4.5 (2 to 6) for mobility. Radiological evaluation revealed migration greater than 5 mm in four acetabular components. Radiological failure matched clinical failure. Asymptomatic radiolucent lines were observed in 31 of 426 areas assessed (7%). Further revision was required in six patients (4.5%), this was due to infection in three and mechanical failure in three. The survival rate for the reconstruction was 95.8% (95% confidence interval 92.3 to 99.1) overall, and 98%, excluding revision due to sepsis.

Our study, from an independent centre, has reproduced the results of the originators of the method.
Synchronous bifocal alveolar rhabdomyosarcoma
Authors: Siegel H. J. , Connor G. S. , Lee D. , Lopez-Ben R. , Kelly D. R.
Published: June 2006

We report a case of bifocal rhabdomyosarcoma involving the hand and thigh in an 11-year-old female. We highlight the importance of a thorough clinical examination and an aggressive surgical approach in which each lesion is treated as a separate primary.
The results of limb lengthening by callus distraction using an extending intramedullary nail (Fitbone) in non-traumatic disorders
Authors: Singh S. , Lahiri A. , Iqbal M.
Published: June 2006

Limb lengthening by callus distraction and external fixation has a high rate of complications. We describe our experience using an intramedullary nail (Fitbone) which contains a motorised and programmable sliding mechanism for limb lengthening and bone transport. Between 2001 and 2004 we lengthened 13 femora and 11 tibiae in ten patients (seven men and three women) with a mean age of 32 years (21 to 47) using this nail. The indications for operation were short stature in six patients and developmental or acquired disorders in the rest.

The mean lengthening achieved was 40 mm (27 to 60). The mean length of stay in hospital was seven days (5 to 9). The mean healing index was 35 days/cm (18.8 to 70.9). There were no cases of implant-related infection or malunion.
Total hip replacement in a patient with systemic mastocytosis
Authors: Fenton P. A. , Suvarna S. K. , Currey J. D. , Hamer A. J.
Published: June 2006

Systemic mastocytosis is a rare condition that often involves the bone marrow. We report the case of a patient with systemic mastocytosis who underwent total hip replacement. Technical difficulties encountered during the procedure included a narrow medullary canal and abnormally hard bone, later confirmed by laboratory measurements. Follow-up at five years showed a good clinical and radiological outcome.
A constrained acetabular component for recurrent dislocation
Authors: Khan R. J. K. , Fick D. , Alakeson R. , Haebich S. , de Cruz M. , Nivbrant B. , Wood D.
Published: June 2006

We treated 34 patients with recurrent dislocation of the hip with a constrained acetabular component. Roentgen stereophotogrammetric analysis was performed to assess migration of the prosthesis.

The mean clinical follow-up was 3.0 years (2.2 to 4.8) and the radiological follow-up was 2.7 years (2.0 to 4.8). At the latest review six patients had died and none was lost to follow-up. There were four acetabular revisions, three for aseptic loosening and one for deep infection. Another acetabular component was radiologically loose with progressive radiolucent lines in all Gruen zones and was awaiting revision. The overall rate of aseptic loosening was 11.8% (4 of 34). Roentgen stereophotogrammetric analysis in the non-revised components confirmed migration of up to 1.06 mm of translation and 2.32° of rotation at 24 months. There was one case of dislocation and dissociation of the component in the same patient. Of the 34 patients, 33 (97.1%) had no further episodes of dislocation.

The constrained acetabular component reported in our study was effective in all but one patient with instability of the hip, but the rate of aseptic loosening was higher than has been reported previously and requires further investigation.
Reconstruction of the anterior cruciate ligament using the polyester ABC ligament scaffold
Authors: Petrou G. , Chardouvelis C. , Kouzoupis A. , Dermon A. , Petrou H. , Tilkeridis C. , Gavras M.
Published: June 2006

We carried out a prospective study of 71 patients who had undergone reconstruction of the anterior cruciate ligament with the ABC scaffold. Their mean age was 28 years (18 to 50). All had either sub-acute or chronic traumatic deficiency of the ligament. The mean period of follow-up was five years (four to seven). Assessment included the use of the International Knee Documentation Committee score, the modified Lysholm score, the Tegner Activity score, the Knee Injury and Osteoarthritis Outcome score and measurement with the KT-1000 arthrometer. Two patients had mild recurrent synovitis. There were no infections and no failures of the ligament. During the period of study, two patients sustained a traumatic fracture of a femoral condyle. The implants retained their integrity in both cases. All patients returned to their previous or enhanced levels of daily activity by three months after operation and 56 (79%) achieved their pre-injury level of sporting activity by six months. The patients who were competing in National level sports returned to play at one level less after operation than before. The Lysholm score showed that 58% of the patients (41) were excellent, 34% (24) good, and 8% (6) fair, with a mean post-operative score of 93. According to the International Knee Documentation Committee score, 35% of knees (25) were ‘normal’, 52% (37) ‘nearly normal’ and 13% (9) ‘abnormal’. Complete satisfaction was noted in 90% of patients (64). The development of osteoarthritis and the management of anterior cruciate deficiency associated with laxity of the medial collateral ligament remains uncertain. Our results indicate that in the medium-term, the ABC ligament scaffold is suitable and effective when early and safe return to unrestricted activities is demanded. We acknowledge the current general hostility towards reconstruction of the anterior cruciate ligament with artificial materials following reports of early failure and chronic synovitis associatiated with the production of particulate debris. We did not encounter these problems.
Alumina ceramic-on-ceramic total hip replacement with a layered acetabular component
Authors: Hasegawa M. , Sudo A. , Uchida A.
Published: June 2006

A modular layered acetabular component (metal-polyethylene-ceramic) was developed in Japan for use in alumina ceramic-on-ceramic total hip replacement. Between May 1999 and July 2000, we performed 35 alumina ceramic-on-ceramic total hip replacements in 30 consecutive patients, using this layered component and evaluated the clinical and radiological results over a mean follow-up of 5.8 years (5 to 6.5). A total of six hips underwent revision, one for infection, two for dislocation with loosening of the acetabular component, two for alumina liner fractures and one for component dissociation with pelvic osteolysis. There were no fractures of the ceramic heads, and no loosening of the femoral or acetabular component in the unrevised hips was seen at final follow-up. Osteolysis was not observed in any of the unrevised hips. The survivorship analysis at six years after surgery was 83%. The layered acetabular component in our experience, has poor durability because of unexpected mechanical failures including alumina liner fracture and component dissociation.
A prospective biomechanical study of the association between foot pronation and the incidence of anterior knee pain among military recruits
Authors: Hetsroni I. , Finestone A. , Milgrom C. , Sira D. Ben , Nyska M. , Radeva-Petrova D. , Ayalon M.
Published: June 2006

Excessive foot pronation has been considered to be related to anterior knee pain. We undertook a prospective study to test the hypothesis that exertional anterior knee pain is related to the static and dynamic parameters of foot pronation. Two weeks before beginning basic training lasting for 14 weeks, 473 infantry recruits were enrolled into the study and underwent two-dimensional measurement of their subtalar joint displacement angle during walking on a treadmill.

Of the 405 soldiers who finished the training 61 (15%) developed exertional anterior knee pain. No consistent association was found between the incidence of anterior knee pain and any of the parameters of foot pronation. While a statistically significant association was found between anterior knee pain and pronation velocity (left foot, p = 0.05; right foot, p = 0.007), the relationship was contradictory for the right and left foot. Our study does not support the hypothesis that anterior knee pain is related to excessive foot pronation.