Identification of a novel phosphonocarboxylate inhibitor of Rab geranylgeranyl transferase that specifically prevents Rab prenylation in osteoclasts and macrophages

Nitrogen-containing bisphosphonate drugs inhibit bone resorption by inhibiting FPP synthase and thereby preventing the synthesis of isoprenoid lipids required for protein prenylation in bone-resorbing osteoclasts. NE10790 is a phosphonocarboxylate analogue of the potent bisphosphonate risedronate and is a weak anti-resorptive agent. Although NE10790 was a poor inhibitor of FPP synthase, it did inhibit prenylation in J774 macrophages and osteoclasts, but only of proteins of molecular mass approximately 22-26 kDa, the prenylation of which was not affected by peptidomimetic inhibitors of either farnesyl transferase (FTI-277) or geranylgeranyl transferase I (GGTI-298). These 22-26-kDa proteins were shown to be geranylgeranylated by labelling J774 cells with [(3)H]geranylgeraniol. Furthermore, NE10790 inhibited incorporation of [(14)C]mevalonic acid into Rab6, but not into H-Ras or Rap1, proteins that are modified by FTase and GGTase I, respectively. These data demonstrate that NE10790 selectively prevents Rab prenylation in intact cells. In accord, NE10790 inhibited the activity of recombinant Rab GGTase in vitro, but did not affect the activity of recombinant FTase or GGTase I. NE10790 therefore appears to be the first specific inhibitor of Rab GGTase to be identified. In contrast to risedronate, NE10790 inhibited bone resorption in vitro without markedly affecting osteoclast number or the F-actin "ring" structure in polarized osteoclasts. However, NE10790 did alter osteoclast morphology, causing the formation of large intracellular vacuoles and protrusion of the basolateral membrane into large, "domed" structures that lacked microvilli. The anti-resorptive activity of NE10790 is thus likely due to disruption of Rab-dependent intracellular membrane trafficking in osteoclasts.

Preliminary comparison of the rupture of human and rabbit anterior cruciate ligaments

OBJECTIVE

This study was aimed at examining ruptures of the human anterior cruciate ligaments by scanning electron microscopy and video imaging and comparing the appearance of the rupture surfaces with those from rabbit anterior cruciate ligaments.

DESIGN

The specimens were tested to failure as femur-anterior cruciate ligament-tibia complexes using an Instron 8511 materials testing machine.

BACKGROUND

Rupture of the anterior cruciate ligament is a major clinical problem, leading to instability of the knee joint. Due to the frequency and potential severity of the injuries, a need still exists for information on the biomechanical properties of ligaments under loading conditions, which occur at the time of trauma.

METHODS

Four human femur-anterior cruciate ligament-tibia complexes were loaded to failure at a displacement rate of 0.008 m/s. Video recordings of the tests were used to study the progress of the ruptures and to compare the modes of failure of the ligaments. Scanning electron microscopy was employed to study the appearance of collagen fibres at the rupture surfaces.

RESULTS

The modes of failure of the rabbit anterior cruciate ligament and appearance of the rupture surfaces were similar to those of the human anterior cruciate ligaments.

CONCLUSION

The rabbit anterior cruciate ligament provides a model for investigating failure of the human ligament during trauma.

RELEVANCE

The results will be of significance since most studies on ligaments are carried out on animal models with the intention of applying the deductions from the results to human ligaments. Examining the appearance of collagen fibres at these surfaces may help us to understand more about what actually happens during and after ligament rupture.

Differentially expressed late constituents of the epidermal cornified envelope

Barrier activity of skin and internal barrier-forming epithelial linings are conferred by a lipid-corneocyte structure (stratum corneum in skin). The integrity of the corneocytes depends on the outer cornified envelope and is essential for maintenance of barrier function. During epidermal development and differentiation, proteins are sequentially incorporated into the envelope via action of epidermal transglutaminases in a well documented process. However, recent knockouts of major cornified envelope constituents have failed to disrupt barrier function significantly, suggesting that additional unidentified components are involved. We report a new gene cluster in the epidermal differentiation complex at human 1q21 encoding a family of 18 proteins that are substrates for epidermal transglutaminases. These proteins incorporate into the cornified envelope late in development and late in the process of envelope maturation during epidermal differentiation. The genes cluster within the epidermal differentiation complex according to expression pattern, i.e., epidermally expressed proteins cluster together while proteins from internal barrier-forming epithelia also cluster. We propose that these proteins modulate barrier activity over the surface of the animal, in a manner analogous to that proposed for the well characterized cornified envelope precursors, the small proline-rich proteins. To emphasize the incorporation of these proteins late in envelope assembly, we call the human proteins late envelope proteins.

Economic decision analysis model of screening for lung cancer

The objective of this study was to evaluate the potential clinical and economic implications of an annual lung cancer screening programme based on helical computed tomography (CT). A decision analysis model was created using combined data from the Surveillance, Epidemiology and End Results (SEER) registry public-use database and published results from the Early Lung Cancer Action Project (ELCAP). We found that under optimal conditions in a high risk cohort of patients between 60 and 74 years of age, annual lung cancer screening over a period of 5 years appears to be cost effective at approximately $19000 per life year saved. A sensitivity analysis of the model to account for a 1-year decrease in survival benefit and changes in assumptions for incidence rate and costs generated cost effectiveness estimates ranging from approximately $10800 to $62000 per life year saved. Based on the assumptions embedded in this model, annual screening of high risk elderly patients for lung cancer may be cost effective under optimal conditions, but longer term data are needed to confirm if this will be borne out in practice.

On the extended depth of focus algorithms for bright field microscopy

Microscopes offer a limited depth of focus which precludes the observation of a complete image of a three-dimensional (3D) object in a single view. Investigations, by a variety of researchers, have led to the development of extended depth of focus algorithms for serial optical slices of microscopic 3D objects in recent years. However, to date, no quantitative comparison of the different algorithms has been performed, generally leaving the evaluation to the subjective qualitative appreciation of the observer. In this paper we use three different tests for extended depth of focus algorithm evaluation and test 10 different algorithms, some of them have been adapted (by us) for a series of optical slices. However, the main contribution of the paper is a new improved algorithm for computing the extended depth of focus.

Psychometric evaluation of Breast Health Behavior Questionnaire: Spanish version

The purpose of the study was to test the psychometric properties of a culturally sensitive and theory-based instrument: the Breast Health Behavior Questionnaire. This instrument was translated into Spanish and back-translated at a third- to fourth-grade reading level. The pilot group consisted of 70 Hispanic women who attended a class at a local church. Subsequent to pilot testing, another 40 Hispanic women who attended a class at the local health department comprised the study sample. The participants responded to the 15-item questionnaire, which is formatted as a Likert scale. Content validity of the Breast Health Behavior Questionnaire was determined by a panel of experts. A factor analysis of this instrument showed five separate dimensions accounting for 71.82% of the instrument's variance. The three major components of self-regulation theory (schema, coping, and appraisal criteria) were found clustered within the first three dimensions after three items were discarded. The Breast Health Behavior Questionnaire demonstrated an internal consistency reliability coefficient of .7172. The psychometric properties of the Spanish version of this questionnaire warrant further research. The instrument may support a better understanding of the Hispanic woman's practice of breast health behavior. Eventually, the Breast Health Behavior Questionnaire may assist nurses in the formulation of culturally grounded interventions.

Limited endothelial E- and P-selectin expression in MRL/lpr lupus-prone mice

OBJECTIVE

Inflammation in MRL/lpr mice may involve dysfunctional leucocyte-endothelial cell (EC) interactions. Previously, we have shown that intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) increase with age in a tumour necrosis factor alpha (TNF alpha)- and interleukin-1 (IL-1)-dependent manner. The object of this study was to determine the expression of E- and P-selectin.

METHODS

Selectin expression was quantified in MRL/lpr mice and BALB/c controls by intravenous injection of differentially radio-labelled antibodies.

RESULTS

E-selectin, but not P-selectin, was up-regulated in the kidneys of older mice. Neither was up-regulated elsewhere. There was no defect in selectin inducibility, as a further inflammatory stimulus (intraperitoneal lipopolysaccharide) resulted in up-regulation. Serum from older MRL/lpr did not induce selectin expression by EC in vitro.

CONCLUSION

The increase in E-selectin in the kidney may contribute to the development of glomerulonephritis. However, the lack of systemic E- and P-selectin expression may represent a protective mechanism which limits the interaction between leucocytes and the endothelium in the chronic inflammatory context.

Specific packaging of nodaviral RNA2 requires the N-terminus of the capsid protein

Flock house virus (FHV), a member of the family Nodaviridae, is a nonenveloped, icosahedral insect virus whose capsids are assembled from 180 copies of a single type of coat protein. The viral genome is split between two segments of single-stranded positive-sense RNA, RNA1 and RNA2, which are packaged into a single virion. We previously demonstrated that synthesis of FHV coat protein in the baculovirus expression system results in assembly of virus-like particles whose capsids are indistinguishable from those of native virions, although the encapsidated RNA represents primarily cellular RNA. In contrast, expression of a deletion mutant lacking N-terminal residues 2-31 results in formation of multiple types of particles which differ in size, shape, and RNA contents. We postulated that the polymorphism was imposed by the type of RNA that the coat protein selected for packaging. In the current study we tested this hypothesis by analyzing the assembly of the mutant coat protein in Drosophila cells in the presence of replicating FHV RNAs. As anticipated, the resulting particles had the same shape and dimensions as wt virions. Surprisingly, however, they contained little RNA2 while packaging of RNA1 was not affected. Small amounts of defective interfering RNAs, which emerged rapidly in the presence of the mutant coat protein, were also detected. Taken together, these observations confirm our earlier hypothesis that selection of nonviral RNAs for packaging can significantly alter the assembly process. In addition, they demonstrate that the N-terminus of the FHV coat protein contains important determinants for recognition and packaging of RNA2. Our results provide the first evidence that encapsidation of the two genomic RNAs occurs independently and that the coat protein uses different regions for the recognition of RNA1 and RNA2.

Potential cost-effectiveness of one-time screening for lung cancer (LC) in a high risk cohort

The development of low-dose helical computed-tomography (CT) scanning to detect nodules as small as a few mm has sparked renewed interest in lung cancer (LC) screening. The objective of this study was to assess the potential health effects and cost-effectiveness of a one-time low-dose helical CT scan to screen for LC. We created a decision analysis model using baseline results from the Early Lung Cancer Action Project (ELCAP); Surveillance, Epidemiology and End Results (SEER) registry public-use database; screening program costs estimated from 1999 Medicare reimbursement rates; and annual costs of managing cancer and non-cancer patients from Riley et al. (1995) [Med Care 1995;33(8):828-841] and Taplin et al. (1995) [J Natl Cancer Inst 1995;87(6):417-26]. The main outcome measures included years of life, cost estimates of baseline diagnostic screening and follow up, and cost-effectiveness of screening. We found that in a very high-risk cohort (LC prevalence of 2.7%) of patients between 60 and 74 years of age, a one-time screen appears to be cost-effective at $5940 per life year saved. In a lower risk general population of smokers (LC prevalence of 0.7%), a one-time screen appears to be cost-effective at $23100 per life year. Even when a lead-time bias of 1 year is incorporated into the model for a low risk population, the cost-effectiveness is estimated at $58183 per life year. Based on the assumptions embedded in this model, one-time screening of elderly high-risk patients for LC appears to be cost-effective.

The effect of flexion angle on the macro and microscopic appearance of the rupture surface of the ACL of rabbits

This study investigated how knee flexion angle affects the appearance of the rupture surface of the anterior cruciate ligament (ACL) using rabbit knees. Specimens were failed at flexion angles of 45 degrees and 90 degrees at displacement rates of 10 and 500 mm/min. Video recordings and scanning electron microscopy (SEM) studied the appearance of the rupture surfaces. At the displacement rate of 10 mm/min, the major mode of failure was fibre pullout for all flexion angles. At displacement rate of 500 mm/min, which more closely approximated loading conditions during trauma, we found that all modes of failure were exhibited. At 45 degrees flexion, the majority of specimens tested failed by avulsion. The reverse was true for specimens tested at 90 degrees where the majority of failures were fibre pullouts. At 45 degrees, there were more pulled-out fibres on rupture surfaces of specimens tested at 10 mm/min than at 500 mm/min. At 90 degrees, little difference was seen in the appearance of ruptures from both rates. SEM revealed that the waviness of collagen fibres was more pronounced at 10 mm/min. Therefore, the appearance of rupture surfaces of ACLs are affected by both flexion angle and displacement rate.

Viral capsid mobility: a dynamic conduit for inactivation

Mass spectrometry and fluorescent probes have provided direct evidence that alkylating agents permeate the protein capsid of naked viruses and chemically inactivate the nucleic acid. N-acetyl-aziridine and a fluorescent alkylating agent, dansyl sulfonate aziridine, inactivated three different viruses, flock house virus, human rhinovirus-14, and foot and mouth disease virus. Mass spectral studies as well as fluorescent probes showed that alkylation of the genome was the mechanism of inactivation. Because particle integrity was not affected by selective alkylation (as shown by electron microscopy and sucrose gradient experiments), it was reasoned that the dynamic nature of the viral capsid acts as a conduit to the interior of the particle. Potential applications include fluorescent labeling for imaging viral genomes in living cells, the sterilization of blood products, vaccine development, and viral inactivation in vivo.

Compression therapy in leg ulcer management

Leg ulcer management is an important consideration for all nurses involved in the care of older people. Non-specialists in tissue viability might not always be aware of the evidence base for best practice. The authors examine the effectiveness of multilayer and single-layer long- or short-stretch bandage systems in leg ulcer management.

Computational and experimental characterization of physically clustered simple sequence repeats in plants

The type and frequency of simple sequence repeats (SSRs) in plant genomes was investigated using the expanding quantity of DNA sequence data deposited in public databases. In Arabidopsis, 306 genomic DNA sequences longer than 10 kb and 36,199 EST sequences were searched for all possible mono- to pentanucleotide repeats. The average frequency of SSRs was one every 6.04 kb in genomic DNA, decreasing to one every 14 kb in ESTs. SSR frequency and type differed between coding, intronic, and intergenic DNA. Similar frequencies were found in other plant species. On the basis of these findings, an approach is proposed and demonstrated for the targeted isolation of single or multiple, physically clustered SSRs linked to any gene that has been mapped using low-copy DNA-based markers. The approach involves sample sequencing a small number of subclones of selected randomly sheared large insert DNA clones (e.g., BACs). It is shown to be both feasible and practicable, given the probability of fortuitously sequencing through an SSR. The approach is demonstrated in barley where sample sequencing 34 subclones of a single BAC selected by hybridization to the Big1 gene revealed three SSRs. These allowed Big1 to be located at the top of barley linkage group 6HS.

Noninflammatory phagocytosis of monosodium urate monohydrate crystals by mouse macrophages. Implications for the control of joint inflammation in gout

OBJECTIVE

We have hypothesized that the process of monocyte to macrophage differentiation may alter the inflammatory response of mononuclear phagocytes to the uptake of monosodium urate monohydrate (MSU) crystals.

METHODS

Eight mouse monocyte/macrophage cell lines were arranged in increasing order of differentiation, as judged by expression of the macrophage markers F4/80 and BM 8 and by phagocytic capacity. Secretion of tumor necrosis factor alpha (TNFalpha) in response to MSU was measured by enzyme-linked immunosorbent assay.

RESULTS

The panel of monocyte/macrophage cell lines revealed a close linkage between the state of differentiation and the capacity of the cells to ingest MSU crystals. TNFalpha production, however, was not linked to phagocytic ability. Peak TNFalpha levels were synthesized by cells at an intermediate state of differentiation (3.2-14.1 ng/ml), whereas mature macrophages, which efficiently phagocytosed crystals, did not secrete TNFalpha. Mature cell lines produced TNFalpha when stimulated with zymosan (5.9-6.2 ng/ml), but this was abolished by coincubation with MSU crystals. Suppression of the zymosan response was not due to apoptosis or steric hindrance by MSU crystals. Culture supernatants from mature macrophages did not stimulate endothelial cell activation, in contrast to MSU-treated cells at an earlier stage of differentiation, which stimulated intercellular adhesion molecule 1 expression on sEND endothelioma cells through the release of TNFalpha (inhibited 80.6% by anti-TNFa).

CONCLUSION

We demonstrated that phagocytosis and TNFalpha production are distinct events in the response of mononuclear phagocytes to urate crystals, and these events can be distinguished at the level of macrophage differentiation. The noninflammatory removal of urate crystals by mature macrophages defines a new pathway that may be important in controlling the development of acute gout in patients with hyperuricemia.

Telemedicine use in two nurse-led minor injuries units

Telemedicine links were established between two nurse-led minor injuries units (MIUs) located in community hospitals and an accident and emergency department in a district general hospital. Telemedicine consultations were logged. During the first year of operation, telemedicine use was surprisingly constant, there being an average of 36 calls a month from one MIU and 16 from the other. Possible reasons for this include the clinical protocols under which nurses could refer patients to hospital. The average duration of teleconsultations was 3.5 min. Although the MIUs dealt with roughly similar numbers of patients, approximately 600-700 per month, the proportion for whom telemedicine was used was very different, at 5.2% and 2.3%.

SPRR1 gene induction and barrier formation occur as coordinated moving fronts in terminally differentiating epithelia

Stratified, terminally differentiated epithelia, such as epidermis and oral epithelia, provide protective barriers against the environment. We recently developed wholemount assays that demonstrate epidermal barrier function during late gestation and showed that epidermal barrier forms at specific sites (epidermal initiation sites), and then spreads around the body as apparent moving fronts. We now ask if this is a fundamental and widespread mode of epithelial developmental change. If so, then the pattern should be apparent when assaying for developmental change other than barrier institution (e.g., gene induction) and similar types of patterned change should be apparent in other types of epithelia. In this study we demonstrate patterned barrier function in a range of additional stratified epithelia from the oral cavity and show that the gene induction pattern of a stratum corneum precursor small proline-rich region protein 1 (SPRR1) precedes barrier function and occurs in the barrier pattern, i.e., gene induction occurs first at initiation sites and propagates across epithelia as apparent moving fronts. These results demonstrate that late gestational developmental change in multiple terminally differentiating epithelia occurs via initiation sites and moving fronts. The pattern precedes barrier formation and results in a developmental gradient that influences gene induction.

Macro and microscopic examination of the ruptured surfaces of anterior cruciate ligaments of rabbits

In a study combining tissue mechanics and fracture morphology for the first time, we examined the ruptured surfaces of anterior cruciate ligaments of rabbits and related their appearance to the initial loading conditions. Sixteen specimens were stretched to failure at rates of displacement of 10 and 500 mm/min. We used video images to study the changes which occurred during the fracture process and SEM to examine the appearance of the ruptured surfaces. The surfaces of ligaments tested at 10 mm/min had more pulled-out collagen fibres and the fibres had more pronounced waviness compared with those tested at 500 mm/min. We have shown that the macroscopic appearance of ruptured ligaments can be related to their microscopic appearance and that it is possible to deduce whether failure was by gradual tearing of the fibres or catastrophic failure.

CD4+ T cell priming accelerates the clearance of Sendai virus in mice, but has a negative effect on CD8+ T cell memory

Current vaccines designed to promote humoral immunity to respiratory virus infections also induce potent CD4+ T cell memory. However, little is known about the impact of primed CD4+ T cells on the immune response to heterologous viruses that are serologically distinct, but that share CD4+ T cell epitopes. In addition, the protective capacity of primed CD4+ T cells has not been fully evaluated. In the present study, we addressed these two issues using a murine Sendai virus model. Mice were primed with an HN421-436 peptide that represents the dominant CD4+ T cell epitope on the hemagglutinin-neuraminidase (HN) of Sendai virus. This vaccination strategy induced strong CD4+ T cell memory to the peptide, but did not induce Abs specific for the Sendai virus virion. Subsequent Sendai virus infection of primed mice resulted in 1) a substantially accelerated virus-specific CD4+ T cell response in the pneumonic lung; 2) enhanced primary antiviral Ab-forming cell response in the mediastinal lymph nodes; and 3) accelerated viral clearance. Interestingly, the virus-specific CD8+ T cell response in the lung and the development of long-term memory CD8+ T cells in the spleen were significantly reduced. Taken together, our data demonstrate that primed CD4+ T cells, in the absence of pre-existing Ab, can have a significant effect on the subsequent immune responses to a respiratory virus infection.

A linkage map of chromosome 6 based on 2 large kindreds segregating bipolar affective disorder

Twenty-eight markers, both simple sequence repeats (SSRs) and restriction fragment length polymorphisms (RFLPs), were genotyped on members of 2 large pedigrees (OOA, BIP167) segregating bipolar affective disorder. Using the multipoint program "build" of CRIMAP and odds of placement 1000:1, a unique sex-averaged map was generated that spans 227 cM and includes 26 markers. The two other markers were placed on the map with a lower likelihood. The female recombination map is larger than the male recombination map by about 80%. Linkage analysis between the polymorphisms and the disease in the OOA screening pedigree did not result in any significantly positive lod scores nor did a non-parametric, identity-by-descent, method generate any significant p-values. BIP167 was analyzed for allele sharing at the simple sequence repeat loci and significant associations were not found. At present we conclude, that the pedigrees under study do not have a major predisposition gene for bipolar affective disorder on chromosome 6 under the diagnostic and transmission models analyzed by the 2 different methods.

Alternative responses to child protective services: emerging issues and concerns

PROBLEM

Increased calls to "do something" about child protective services (CPS) have resulted in proposals or new "paradigms" for services to at-risk or abusive families. These new paradigms call for the reform or revamping of CPS through the development of a community-based alternative response to some reports of child abuse and/or neglect.

METHOD

This article reports on outcomes for 1,263 "low" risk CPS referrals diverted to a community-based alternative response system. Data on child, family, and case characteristics and services provided are presented as well as outcomes associated with re-referral and placement post service provision.

RESULTS

The risk level and severity of some of the referrals to alternative response systems seems inappropriately high. The rates of re-referral were similar for families who did or did not engage in assessment services, and were highest for families where domestic violence was present.

CONCLUSIONS

Criteria for diversion to community alternatives to CPS must be clearly articulated and applied. Both CPS and alternative response system workers must have the skills required to address a family's recognition of the problem and degree of motivation to engage in problem resolution, and to understand their relationship to continued risk of CA/N.