Automated Analysis of Preceptor Comments: A Pilot Study Using Sentiment Analysis to Identify Potential Student Issues in Experiential Education

OBJECTIVE

The purpose of this paper is to describe a sentiment analysis program that aids in identifying pharmacy students at risk for progression issues by automatically scoring preceptor comments as positive or negative.

METHODS

An R-based program to analyze advanced pharmacy practice experiences and introductory pharmacy practice experiences midpoint evaluation of preceptor comments was piloted in phase 1 by comparing the sentiment analysis algorithm results to human coding. The algorithm was refined in phase 2. In phase 3, the validation phase, the final sentiment analysis algorithm analyzed all midpoint student evaluations (n = 1560). Sentiment scores were generated for each preceptor comment, and correlations were performed between sentiment scores and the quantitative scoring provided on the assessment.

RESULTS

In phase 1, agreement between faculty coders and sentiment analysis was 96%, and in phase 2, agreement between the final codes and sentiment analysis was 92.4% once keywords were added to the sentiment dictionary. In phase 3, a total of 3919 comments from 1560 evaluations were analyzed, and overall, the sentiment analysis results aligned with the quantitative data.

CONCLUSION

This sentiment analysis algorithm was accurate in capturing positive and negative comments corresponding to pharmacy student performance. Given the accuracy of this preliminary validation for flagging preceptor comments, there are numerous implications when considering the use of sentiment analysis in pharmacy education. Using a sentiment analysis program minimizes the number of qualitative preceptor comments needing review by experiential faculty, as this program can aid in identifying students at risk of progression issues.

Preceptor perceptions of a redesigned entrustable professional activity (EPA) assessment tool in pharmacy practice experiences

INTRODUCTION

The purpose of this study was to determine pharmacy preceptor perceptions of an entrustable professional activity (EPA) evaluation tool redesigned in 2019 and launched for use in May 2020.

METHODS

Participants received an optional survey in June 2021 regarding their perceptions of the redesigned EPA assessment tool. The survey used a combination of open- and closed-ended questions regarding preceptor perceptions of the revised form, including perceptions of accuracy, usability, ease of use, grading, EPAs, and form layout. Preceptor perceptions were measured using seven-point Likert-type items and analyzed with descriptive statistics. Open-ended items were coded by at least two faculty members using qualitative content analysis.

RESULTS

We received 106 responses (19.5% response rate) and analyzed a total of 91 responses. Most questions related to perceived accuracy were rated positively, and preceptors indicated it was easier to assign grades and provide feedback on EPAs using the new form. Preceptors agreed that EPAs indicated when students on clinical rotations excel and when they need to improve. Preceptors reported they could effectively evaluate students and do so in a way that saves them time. Overall, preceptors agreed that the form instructions helped them accurately assess student performance, and the new narratives helped them remember the assessment standards.

CONCLUSIONS

Overarchingly, preceptors perceived that the new EPA assessment tool allowed them to provide feedback and grades more accurately, efficiently, effectively, and easily. This information will assist our institution in determining next best steps for EPA assessment tool updates.

An introduction to text analytics for educators

OUR SITUATION

Educators often find themselves in possession of large amounts of text-based materials, such as student reflections, narrative feedback, and assignments. While these materials can provide critical insight into topics of interest, they also require a substantial amount of time to read, interpret, and use. The purpose of this article is to describe and provide recommendations for text analytics.

METHODOLOGICAL LITERATURE REVIEW

An overview of text analytics is provided, including a brief history, common types of contemporary techniques, and the basic phases of text analytics. Several examples of common text analytics techniques are used to illustrate this approach.

OUR RECOMMENDATIONS AND THEIR APPLICATIONS

Practical recommendations are provided to support the use of text analytics in pharmacy education. These recommendations include: (1) clarify the purpose of the text analytics; (2) ensure the research questions are relevant and grounded in the literature; (3) develop a processing strategy and create a dictionary; (4) explore various tools for analysis and visualization; (5) establish tolerance for error; (6) train, calibrate, and validate the analytic strategy; and (7) collaborate and equip yourself.

POTENTIAL IMPACT

Text analytics provide a systematic approach to generating information from text-based materials. Several benefits to this approach are apparent, such as improving the efficiency of analyzing text and elucidating new knowledge. Despite recent developments in text analytics techniques, limitations to this approach remain. Efforts to improve usability and accessibility of text analytics remain ongoing, and pharmacy educators should position their work within the context of these limitations.

Hydraulic failure and tree size linked with canopy die-back in eucalypt forest during extreme drought

Eastern Australia was subject to its hottest and driest year on record in 2019. This extreme drought resulted in massive canopy die-back in eucalypt forests. The role of hydraulic failure and tree size on canopy die-back in three eucalypt tree species during this drought was examined. We measured pre-dawn and midday leaf water potential (Ψleaf ), per cent loss of stem hydraulic conductivity and quantified hydraulic vulnerability to drought-induced xylem embolism. Tree size and tree health was also surveyed. Trees with most, or all, of their foliage dead exhibited high rates of native embolism (78-100%). This is in contrast to trees with partial canopy die-back (30-70% canopy die-back: 72-78% native embolism), or relatively healthy trees (little evidence of canopy die-back: 25-31% native embolism). Midday Ψleaf was significantly more negative in trees exhibiting partial canopy die-back (-2.7 to -6.3 MPa), compared with relatively healthy trees (-2.1 to -4.5 MPa). In two of the species the majority of individuals showing complete canopy die-back were in the small size classes. Our results indicate that hydraulic failure is strongly associated with canopy die-back during drought in eucalypt forests. Our study provides valuable field data to help constrain models predicting mortality risk.

Translating Dental, Oral, and Craniofacial Regenerative Medicine Innovations to the Clinic through Interdisciplinary Commercial Translation Architecture

Few university-based regenerative medicine innovations in the dental, oral, and craniofacial (DOC) space have been commercialized and affected clinical practice in the United States. An analysis of the commercial translation literature and National Institute for Dental and Craniofacial Research's (NIDCR's) portfolio identified barriers to commercial translation of university-based DOC innovations. To overcome these barriers, the NIDCR established the Dental Oral Craniofacial Tissue Regeneration Consortium. We provide generalized strategies to inform readers how to bridge the "valley of death" and more effectively translate DOC technologies from the research laboratory or early stage company environment to clinical trials and bring needed innovations to the clinic. Three valleys of death are covered: 1) from basic science to translational development, 2) from translational technology validation to new company formation (or licensing to an existing company), and 3) from new company formation to scaling toward commercialization. An adapted phase-gate model is presented to inform DOC regenerative medicine teams how to involve regulatory, manufacturability, intellectual property, competitive assessments, business models, and commercially oriented funding mechanisms earlier in the translational development process. An Industrial Partners Program describes how to conduct market assessments, industry maps, business development processes, and industry relationship management methods to sustain commercial translation through the later-stage valley of death. Paramount to successfully implementing these methods is the coordination and collaboration of interdisciplinary teams around specific commercial translation goals and objectives. We also provide several case studies for translational projects with an emphasis on how they addressed DOC biomaterials for tissue regeneration within a rigorous commercial translation development environment. These generalized strategies and methods support innovations within a university-based and early stage company-based translational development process, traversing the many funding gaps in dental, oral, and craniofacial regenerative medicine innovations. Although the focus is on shepherding technologies through the US Food and Drug Administration, the approaches are applicable worldwide.

Syndrome of Inappropriate Anti-Diuretic Hormone Secretion Secondary to Strongyloides stercoralis Infection in an Allogeneic Stem Cell Transplant Patient: A Case Report and Literature Review

Syndrome of inappropriate anti-diuretic hormone (SIADH) has been reported to be associated with systemic Strongyloides stercoralis. Here, we report a case of a stem cell transplant (SCT) recipient who developed severe SIADH secondary to systemic S Stercoralis. The SIADH resolved quickly after treating the systemic S Stercoralis with ivermectin. A systematic review of the literature was performed by PubMed, Scopus, and Cochrane database search. Only eight cases of S Stercoralis in allogeneic SCT recipients have been previously reported. To our knowledge, ours is the first reported case of SIADH secondary to S Stercoralis infection in an allogeneic SCT recipient. Prior to transplantation, even if asymptomatic, patients from endemic regions should be screened with strongyloides immunoglobulin (Ig)G serology. Pretransplantation eosinophilia should be evaluated by screening multiple stool samples for ova and parasites. Transplant candidates with positive serology or stool tests can be treated pretransplantation to eradicate infection. Patients at risk for S Stercoralis who develop nonspecific gastrointestinal complaints, rash, pulmonary infiltrates, or gram-negative bacteremia or meningitis may have S Stercoralis hyperinfection syndrome. Our case indicates that the development of SIADH may be an additional clue to this diagnosis. Appropriate diagnostic studies, including repeat stool and other body fluid sampling, should be expedited and ivermectin therapy initiated rapidly to prevent significant morbidity and mortality.

An active, collaborative approach to learning skills in flow cytometry

Advances in science education research have the potential to improve the way students learn to perform scientific interpretations and understand science concepts. We developed active, collaborative activities to teach skills in manipulating flow cytometry data using FlowJo software. Undergraduate students were given compensated clinical flow cytometry listmode output (FCS) files and asked to design a gating strategy to diagnose patients with different hematological malignancies on the basis of their immunophenotype. A separate cohort of research trainees was given uncompensated data files on which they performed their own compensation, calculated the antibody staining index, designed a sequential gating strategy, and quantified rare immune cell subsets. Student engagement, confidence, and perceptions of flow cytometry were assessed using a survey. Competency against the learning outcomes was assessed by asking students to undertake tasks that required understanding of flow cytometry dot plot data and gating sequences. The active, collaborative approach allowed students to achieve learning outcomes not previously possible with traditional teaching formats, for example, having students design their own gating strategy, without forgoing essential outcomes such as the interpretation of dot plots. In undergraduate students, favorable perceptions of flow cytometry as a field and as a potential career choice were correlated with student confidence but not the ability to perform flow cytometry data analysis. We demonstrate that this new pedagogical approach to teaching flow cytometry is beneficial for student understanding and interpretation of complex concepts. It should be considered as a useful new method for incorporating complex data analysis tasks such as flow cytometry into curricula.

Mutational Analysis of BRAF Inhibitor-Associated Squamoproliferative Lesions

In recent years, there has been increasing use of BRAF-inhibiting drugs for the treatment of various malignancies, including melanoma. However, these agents are associated with the development of other nonmelanoma skin lesions, in particular squamoproliferative lesions such as keratoacanthomas (KAs), squamous cell carcinomas, and BRAF inhibitor-associated verrucous keratoses. The molecular pathogenesis of these lesions is of interest, not only for therapeutic reasons, but also for the insight it might provide into the development of similar lesions in a sporadic setting. We used next-generation sequencing to compare the mutational profiles of lesions after treatment with a BRAF inhibitor, with similar lesions arising sporadically. HRAS mutations were common among the BRAF inhibitor-induced lesions, being identified in 56%, compared with 14% of lesions in the sporadic group (P = 0.002). Thus, despite similar histomorphological appearances, the underlying molecular mechanisms may be different. In addition, within the BRAF inhibitor-associated group, the lesions designated as KAs and BRAF inhibitor-associated verrucous keratoses had a similar mutational profile (mutations in PIK3CA, APC, and HRAS), which was distinct to that seen in squamous cell carcinomas (FGFR3, CDKN2A, and STK11). We have previously noted histological overlap between KAs and BRAF inhibitor-associated verrucous keratoses, and this finding supports the notion that they may represent morphological or temporal variants of a single lesion type.

Measurement of monocyte-platelet aggregates by imaging flow cytometry

Platelets are subcellular blood elements with a well-established role in haemostasis. Upon activation platelets express P-Selectin (CD62P) on the cell membrane and bind to P-Selectin glycoprotein ligand 1 expressing monocytes, influencing them toward a pro-adhesive and inflammatory phenotype. It is well established that elevated circulating monocyte-platelet aggregates (MPAs) are linked to atherothrombosis in high risk patients. However, whole blood flow cytometry (FCM) has recently shown that circulating MPAs may also occur in the absence of platelet activation, particularly in healthy children. A potential limitation of conventional FCM is the potential for coincident events to resemble monocyte platelet aggregates. Here we report a novel imaging cytometry approach to further characterize monocyte-platelet aggregate formation by P-Selectin dependent and P-Selectin independent mechanisms and distinguish circulating MPAs from coincidental events. Monocytes were identified by expression of the lipopolysachharide receptor (CD14 BV421), while platelets were identified by expression of the glycoprotein Ib (CD42b APC). Differentiation of P-Selectin dependent and P-Selectin independent binding was achieved with AF488 labeled CD62P. Overall analysis of circulating and in vitro generated MPAs by conventional and imaging cytometry methods showed very strong correlation (r(2)  = >0.99, P < 0.01). The Bland-Altman bias of -1.72 was not significantly different to zero. However, when measuring only P-Selectin negative MPAs, a lack of correlation (r(2)  = 0.27, P = n.s.) likely reflects better discrimination of coincidence events using imaging cytometry. Our data demonstrate that IFC is more accurate in enumerating MPAs than conventional FCM, which over-estimates the number of MPAs due to the presence of coincident events.

How are osteoclasts induced to resorb bone?

Although much is known about how osteoclasts are formed, we know little about how they are activated, or how they recognize bone as the substrate appropriate for resorption. Bone mineral is considered to be essential to this recognition process, but a "mineral receptor" has never been identified. Recently, we found that resorptive behavior, as judged by the formation of ruffled borders and actin rings, occurs on ordinary tissue culture substrates if they are first coated with vitronectin. Similarly, vitronectin-coated substrates induce osteoclasts to secrete tartrate-resistant acid phosphatase and to form podosome belts, and to make resorption trails in the protein that coat the substrate. The same applies to bone mineral, which only induces resorptive behavior if coated with vitronectin. In contrast, fibronectin has none of these effects, despite inducing adhesion and spreading. It appears that osteoclasts recognize bone as the substrate appropriate for resorption through the high affinity of vitronectin-receptor ligands for bone mineral.

Growing season surface water loading of fecal indicator organisms within a rural watershed

The loading of microbial contaminants was examined within the Thomas Brook watershed, a 784 ha mixed land-use catchment located in the headwaters of the Cornwallis River drainage basin (Nova Scotia, Canada). The objectives were to: (i) examine spatial and temporal characteristics of fecal bacteria loading during the growing season from five subwatersheds, and (ii) develop areal fecal indicator organism export coefficients for rural landscapes. Fecal coliform, Escherichia coli, total suspended solids (TSS) concentrations and stream flow were monitored at five locations in the watershed over six consecutive growing seasons (May-Oct, 2001-2006). A nested watershed monitoring approach was used to determine bacterial loading from distinct source types (residential vs. agricultural) during both baseflow and stormflow periods. Areal bacterial loading rates increased in each nested watershed moving downstream through the watershed and were highest in the three subcatchments dominated by agricultural activities. Upper watershed bacterial loading throughout the growing season from an agricultural subcatchment (Growing Season Avg 8.92 x 10(10) CFU ha(-1)) was consistently higher than a residential subcatchment (Growing Season Avg 8.43 x 10(9) CFU ha(-1)). As expected, annual average stormflow bacterial loads were higher than baseflow loads, however baseflow loads still comprised between 14 and 35% of the growing season bacterial loads in the five subwatersheds. Fecal bacteria loads were greater during years with higher annual precipitation. A positive linear relationship was observed between E. coli and TSS loading during the 2005 and 2006 growing seasons when both parameters were monitored, indicating that the processes of sediment transport and bacterial transport are linked. It is anticipated that computed areal microbial loading coefficients will be useful in developing watershed management plans. More intensive sampling during stormflow events is recommended for improving these coefficients.

A young man with hyperimmunoglobulin-E syndrome and IgA and IgG deficiencies

Hyperimmunoglobulin E syndrome (HIES) with recurrent infection is a rare primary immunodeficiency characterized by the clinical triad of recurrent staphylococcal abscesses, cyst-forming pneumonia and an elevated serum immunoglobulin (Ig)E level. We report an 18-year-old man with recurrent chest infections, skin infections and dermatitis. On examination, he had the characteristic facies of HIES: high arched palate, webbing between his thumb and index finger bilaterally, and extensive scarring from multiple staphylococcal skin abscesses. He had an elevated IgE level of 14 300 kU/L. IgA and IgG deficiencies were also identified, which are rare associations of this syndrome and complicated the patient's treatment. The coexistence of HIES, IgA and IgG deficiencies has, to our knowledge, not been reported previously in the literature.

Mitf-PU.1 interactions with the tartrate-resistant acid phosphatase gene promoter during osteoclast differentiation

It has been postulated that the transcription factors micropthalmia associated factor (Mitf) and PU.1 interact with the tartrate-resistant acid phosphatase (TRAP) gene promoter and activate TRAP gene expression in osteoclasts. However, studies on the interaction of these factors with the TRAP promoter employing nuclear extracts from osteoclasts and osteoclast precursors have not been reported. We therefore treated murine mononuclear phagocyte cells with various cytokines to generate cultures of osteoclasts and macrophagic cells with high or low potential to form osteoclasts. The presence of Mitf and PU.1 in nuclear extracts from these cultures and the ability of these factors to bind to the TRAP promoter was then assessed. We demonstrate that Mitf and a related factor, TFE3, are present in nuclear extracts from all cultures and bind the TRAP promoter. While PU.1 is present in nuclear extracts from all cultures, it does not significantly interact with a putative binding site in the TRAP promoter. These results suggest Mitf and PU.1 interactions with the TRAP promoter are not responsible for the specific activation of TRAP gene expression in osteoclasts.

Aberrant monocyte prostaglandin synthase 2 (PGS2) expression in type 1 diabetes before and after disease onset

METHODS

We examined monocyte prostaglandin synthase 2 (PGS2/COX2) expression in individuals at risk for or with type 1 diabetes including: (i) 58 established type 1 and 2 diabetic patients; (ii) 34 autoantibody positive (AA+) children and adults; (iii) 164 infants and young children with insulin-dependent diabetes mellitus (IDDM) susceptibility human leukocyte antigen (HLA) alleles; and (iv) 37 healthy control individuals, over a 5-yr period.

RESULTS

Established type 1 diabetic patients (1 month to 30+ yr post-disease onset) had significantly higher PGS2 expression than healthy controls; by contrast, insulin-treated type 2 diabetic patients had significantly lower PGS2 expression than healthy controls. Longitudinal studies of AA+ subjects at risk for type 1 diabetes indicated that 73% (11/15) of individuals who developed this disease during the study period expressed high levels of PGS2 prior to or after onset. We also found high level PGS2 expression in genetically at-risk infants and young children that correlated with having a first-degree relative with type 1 diabetes, but not with age, gender, or HLA genotype. In this population, high level PGS2 expression coincided with or preceded autoantibody detection in 30% (3/10) of subjects.

CONCLUSIONS

These findings suggest that high level monocyte PGS2 expression, although subject to fluctuation, is present in at-risk subjects at an early age and is maintained during progression to and after type 1 diabetes onset.

Early detection of cytomegalovirus (CMV) infection in bone marrow transplant patients by reverse transcription-PCR for CMV spliced late gene UL21.5: a two site evaluation

BACKGROUND

Bone marrow transplant (BMT) patients at risk of developing cytomegalovirus (CMV) pneumonitis are identified routinely by the early detection of virus in blood. For early diagnosis of CMV infection, the RNA-based approach demonstrates advantages when compared with the current CMV antigen and DNA detection methods.

OBJECTIVES

We have evaluated our previously developed reverse transcription-polymerase chain reaction (RT-PCR) to a spliced late CMV gene (SLG; J. Virol. Methods 56 (1996), 139) to monitor CMV infection in BMT patients at two clinical sites. The diagnostic value of the SLG RT-PCR was compared with the routine CMV antigen and DNA detection methods.

STUDY DESIGN

Weekly blood samples from BMT patients were tested for CMV during the first 3 months post-transplant. The qualitative SLG RT-PCR, semiquantitative DNA PCR, and viral antigen tests were compared. The RNA and DNA PCR results were analysed in terms of their temporal relationship and consistency of CMV detection and compared with CMV infection diagnosed by viral antigen tests.

RESULTS

Of the 101 BMT recipients studied, 25 developed CMV antigenemia and/or DNAemia resulting in symptomatic infection in two patients. All CMV PCR-positive patients were either CMV seropositive pretransplant or received marrow from seropositive donor. The highest incidence of CMV infection was seen in seropositive recipients (R+) irrespective of the donor's status. Detection of CMV infection by SLG RNA preceded CMV DNA detection by 0-2 weeks (median 1 week) and CMV antigen detection by 0-8 weeks (median 3 weeks). Once detected, the SLG RNA remained consistently positive before antiviral treatment was commenced. Both the SLG RNA and CMV DNA detection methods had the same clinical sensitivity, specificity, positive and negative predictive values of 100, 94, 80 and 100%, respectively.

CONCLUSIONS

The RT-PCR for SLG RNA proved to be the earliest indicator of CMV infection in BMT patients demonstrating a sustained pattern of CMV detection during the 3 months post-transplant period. Although very similar in its diagnostic performance to CMV DNA PCR the SLG RNA RT-PCR does not require quantitation and provides an efficient and ongoing indication of active CMV infection.

FLT3 ligand can substitute for macrophage colony-stimulating factor in support of osteoclast differentiation and function

Although bone resorption and osteoclast numbers are reduced in osteopetrotic (op/op) mice, osteoclasts are nevertheless present and functional, despite the absence of macrophage colony-stimulating factor (M-CSF). This suggests that alternative factors can partly compensate for the crucial actions of M-CSF in osteoclast induction. It was found that when nonadherent bone marrow cells were incubated in RANKL with Flt3 ligand (FL) without exogenous M-CSF, tartrate-resistance acid phosphatase (TRAP)-positive cells were formed, and bone resorption occurred. Without FL, only macrophagelike TRAP-negative cells were present. Granulocyte-macrophage CSF, stem cell factor, interleukin-3, and vascular endothelial growth factor could not similarly replace the need for M-CSF. TRAP-positive cell induction in FL was not due to synergy with M-CSF produced by the bone marrow cells themselves because FL also enabled their formation from the hemopoietic cells of op/op mice, which lack any M-CSF. FL appeared to substitute for M-CSF by supporting the differentiation of adherent cells that express mRNA for RANK and responsiveness to RANKL. To determine whether FL can account for the compensation for M-CSF deficiency that occurs in vivo, FL signaling was blockaded in op/op mice by the injection of soluble recombinant Flt3. It was found that the soluble receptor induced a substantial decrease in osteoclast number, strongly suggesting that FL is responsible for the partial compensation for M-CSF deficiency that occurs in these mice.

TGF-beta 1 and IFN-gamma direct macrophage activation by TNF-alpha to osteoclastic or cytocidal phenotype

TNF-related activation-induced cytokine (TRANCE; also called receptor activator of NF-kappaB ligand (RANKL), osteoclast differentiation factor (ODF), osteoprotegerin ligand (OPGL), and TNFSF11) induces the differentiation of progenitors of the mononuclear phagocyte lineage into osteoclasts in the presence of M-CSF. Surprisingly, in view of its potent ability to induce inflammation and activate macrophage cytocidal function, TNF-alpha has also been found to induce osteoclast-like cells in vitro under similar conditions. This raises questions concerning both the nature of osteoclasts and the mechanism of lineage choice in mononuclear phagocytes. We found that, as with TRANCE, the macrophage deactivator TGF-beta(1) strongly promoted TNF-alpha-induced osteoclast-like cell formation from immature bone marrow macrophages. This was abolished by IFN-gamma. However, TRANCE did not share the ability of TNF-alpha to activate NO production or heighten respiratory burst potential by macrophages, or induce inflammation on s.c. injection into mice. This suggests that TGF-beta(1) promotes osteoclast formation not only by inhibiting cytocidal behavior, but also by actively directing TNF-alpha activation of precursors toward osteoclasts. The osteoclast appears to be an equivalent, alternative destiny for precursors to that of cytocidal macrophage, and may represent an activated variant of scavenger macrophage.

Activation of osteoclasts by interleukin-1: divergent responsiveness in osteoclasts formed in vivo and in vitro

Recently, it has been found that osteoclasts are induced and activated by osteoblastic cells through expression of receptor activator NF-kB ligand (RANKL), and that soluble recombinant RANKL, with M-CSF, can replace the need for osteoblastic cells in osteoclast formation. We exploited this opportunity to compare the responsiveness of osteoclast-like cells (OCL) formed in vitro in the absence of osteoblasts, with that of osteoclasts ex vivo. We found that while OCL responded to several hormones and cytokines like ex vivo osteoclasts, their responsiveness to interleukin-1 (IL-1) was fundamentally different: IL1 directly stimulated actin ring formation in OCL, but had no effect on actin rings or survival in osteoclasts ex vivo unless osteoblastic cells were present. This difference could not be attributed to the use of plastic culture substrates for OCL formation, nor to osteoblastic contamination, and did not seem to be mediated by the macrophages that form in OCL cultures. To understand the mechanisms by which IL-1 induces bone loss, it will need to be determined whether or not IL-1-responsive OCLs have a counterpart in vivo. Whichever is the case, our data suggest that the behavior of osteoclasts formed in culture will not always predict that of osteoclasts in vivo.

Osteoclast lineage commitment of bone marrow precursors through expression of membrane-bound TRANCE

Osteoclast formation from hemopoietic precursors is induced by TRANCE (also called RANKL, ODF, and OPGL), a membrane-bound ligand expressed by bone marrow stromal cells. Because soluble recombinant TRANCE is a suboptimal osteoclastogenic stimulus, and to eliminate the need for such dependence on stromal cells, membrane-bound TRANCE was expressed in hematopoietic precursors using retroviral gene transfer. Four TRANCE-expressing osteoclast cell lines were established that continuously generate large numbers of multinucleated cells and express tartrate-resistant acid phosphatase and calcitonin receptors. The multinuclear cells are long-lived and either fuse continuously with each other and with mononuclear cells to form enormous syncytia, or separate to form daughter multinuclear cells. When formed on bone, but not on plastic, the majority of multinuclear cells develop actin rings on bone, and resorb bone, suggesting that bone matrix may provide additional signals that facilitate osteoclastic functional maturation. Surprisingly, multinuclear cells originate from fusion of proliferating mononuclear cells that strongly express the mature macrophage markers F4/80 and Fc receptor, which are not expressed by osteoclasts. These results indicate that osteoclasts can be derived from F4/80-positive and Fc receptor-positive cells, and that TRANCE induces osteoclastic differentiation partly by suppressing the macrophage phenotype.

A role for TGFbeta(1) in osteoclast differentiation and survival

Recently, tumour necrosis factor-related activation-induced cytokine (TRANCE) was shown to be necessary for osteoclast formation. We now report that TGF(beta), a cytokine enriched in bone matrix, is also required. TGF(beta) not only powerfully synergized with TRANCE for induction of osteoclast-like cells (OCL) from bone marrow precursors and monocytes, but OCL formation was abolished by recombinant soluble TGF(beta) receptor II (TGF(beta)sRII). Preincubation in TGF(beta) was as effective as simultaneous incubation with TRANCE. TGF(beta)-preincubation enhanced OCL formation at least partly by preventing the development of resistance to OCL-induction that otherwise occurs when precursors are incubated in M-CSF. OCL formed in TRANCE also showed more rapid apoptosis than OCL in TRANCE plus TGF(beta). Like TGF(beta), incubation on bone matrix prolonged and enhanced the sensitivity of precursors to OCL-induction by TRANCE, and this was reversed by TGF(beta)sRII. Taken together, this data is compelling evidence for a model in which TGF(beta) in matrix or released from bone-lining or other cells maintains and enhances the osteoclast-forming potential of precursors as they migrate towards sites of cell-bound TRANCE. Thus, the specific circumstances necessary for osteoclast formation and survival are TRANCE expression on osteoblastic cells and TGF(beta) in bone.

Activin A is an essential cofactor for osteoclast induction

Recently, receptor activator of NF-kappaB ligand (RANKL) was shown to be necessary for osteoclast formation. We now report that activin A, a cytokine enriched in bone matrix and secreted by osteoblasts and osteoclasts, powerfully synergized with RANKL for induction of osteoclast-like cells (OCL) from bone marrow precursors depleted of stromal cells. Moreover, OCL formation in RANKL was virtually abolished by soluble type II A activin receptors (ActR-II(A)), suggesting that activin A is essential for OCL formation. Activin A was most effective when precursors were exposed to RANKL and activin A simultaneously: resistance to OCL-induction that occurs when precursors are pre-incubated in M-CSF was reduced. Incubation on bone matrix also enhanced the sensitivity of precursors to OCL-induction by RANKL; and this was prevented by soluble ActR-II(A). Thus, activin A in bone matrix, or released from osteoblastic or other cells, enhances the osteoclast-forming potential of precursors and synergizes with RANKL in inducing osteoclastic differentiation.

Prospective audit of cytomegalovirus-negative blood product utilization in haematology/oncology patients

The transfusion management of immunocompromised patients often requires special blood product use such as cytomegalovirus (CMV)-negative cellular products, which are more costly than standard blood products and occasionally in short supply. We audited the use of CMV-negative products in haematology/oncology patients to determine the appropriateness of their use. A concurrent-prospective audit was conducted of all orders for CMV-negative packed red blood cell (PRBC) and platelet products in 201 haematology/ oncology patients. Once CMV serostatus was determined, orders for inappropriate CMV-negative units were cancelled, and filled as CMV untested units. During the 21-month period of this audit, the rates of inappropriate transfusions decreased for PRBC from 73.2% to 14.3% (chi2 = 68.4, P<0.001) and for platelets from 68.1% to 10.6% (chi2 = 65.6, P<0.001). The median time to cancellation of inappropriate CMV-negative orders was 11 days. This audit resulted in estimated cost savings of $16500 over the 21-month duration. Inappropriate requests for scarce and expensive blood products are substantially reduced by concurrent-prospective auditing of transfusion practice, in a manner that is both simple and cost effective.

Aberrant prostaglandin synthase 2 expression defines an antigen-presenting cell defect for insulin-dependent diabetes mellitus

Prostaglandins (PGs) are lipid molecules that profoundly affect cellular processes including inflammation and immune response. Pathways contributing to PG output are highly regulated in antigen-presenting cells such as macrophages and monocytes, which produce large quantities of these molecules upon activation. In this report, we demonstrate aberrant constitutive expression of the normally inducible cyclooxygenase PG synthase 2 (PGS(2)/ COX-2) in nonactivated monocytes of humans with insulin-dependent diabetes mellitus (IDDM) and those with islet autoantibodies at increased risk of developing this disease. Constitutive PGS(2) appears to characterize a high risk for diabetes as it correlates with and predicts a low first-phase insulin response in autoantibody-positive subjects. Abnormal PGS(2) expression in at-risk subjects affected immune response in vitro, as the presence of a specific PGS(2) inhibitor, NS398, significantly increased IL-2 receptor alpha-chain (CD25) expression on phytohemagglutinin-stimulated T cells. The effect of PGS(2) on CD25 expression was most profound in subjects expressing both DR04 and DQbeta0302 high-risk alleles, suggesting that this cyclooxygenase interacts with diabetes-associated MHC class II antigens to limit T-cell activation. These results indicate that constitutive PGS(2) expression in monocytes defines an antigen-presenting cell defect affecting immune response, and that this expression is a novel cell-associated risk marker for IDDM.

Prostaglandin E2 cooperates with TRANCE in osteoclast induction from hemopoietic precursors: synergistic activation of differentiation, cell spreading, and fusion

It was recently found that osteoblastic cells express TRANCE (tumor necrosis factor-related activation-induced cytokine), a newly identified member of the tumor necrosis factor superfamily, and that expression was increased by calciotropic hormones. Furthermore, soluble recombinant TRANCE induces osteoclast formation and resorption in stroma-free populations of hemopoietic precursor cells. However, overexpression of the decoy receptor osteoprotegerin in vivo shows that there are substantial differences in the sensitivity of different sites to resorption-inhibition, suggesting that either alternative ligands exist or the sensitivity of osteoclasts to TRANCE can be modified by cofactors. We therefore tested the possibility that cofactors might enhance osteoclast formation by TRANCE. We found that the number of tartrate-resistant acid phosphatase-positive and calcitonin receptor-positive cells was increased by a factor of 10 by the presence of PGE2 in the absence of stromal cells. Moreover, although the tartrate-resistant acid phosphatase-positive cells that formed in TRANCE alone were typically mononuclear and poorly spread, the addition of PGE2 induced the formation of large, well spread multinuclear cells. There was an increase in bone resorption that corresponded with the increase in osteoclast number. PGE2 did not synergize with TRANCE for resorption-stimulation in mature cells. 8-Bromo-cAMP showed a similar syngergistic effect on osteoclastic differentiation. Thus, PGE2 appears to stimulate bone resorption through a direct effect on hemopoietic precursors, primarily through a synergistic effect on the ability of TRANCE to induce osteoclastic differentiation.

A brief medical necessity scale for mental disorders: reliability, validity, and clinical utility

Managed care organizations (MCOs) use the concept of "medical necessity" to decide whether a prescribed treatment is warranted for a given medical condition. Because mental disorders lack the objective disease criteria common to medical illness, behavioral health administrators need a validated means to identify and quantify the severity of "medically important" aspects of mental disorders. The authors developed and tested a brief medical necessity scale for mental disorders in 205 patients presenting for initial evaluation. The scale had a factor structure with four subscales; good internal consistency, interrater reliability, and concurrent and predictive validity; and modest ability to identify patients requiring hospitalization and, in hospitalized patients, those requiring involuntary hospitalization. The authors propose use of the scale to better clarify decisions about level of care assignments and to better assess patient characteristics predictive of good outcome.

TRANCE is necessary and sufficient for osteoblast-mediated activation of bone resorption in osteoclasts

TRANCE (tumor necrosis factor-related activation-induced cytokine) is a recently described member of the tumor necrosis factor superfamily that stimulates dendritic cell survival and has also been found to induce osteoclastic differentiation from hemopoietic precursors. However, its effects on mature osteoclasts have not been defined. It has long been recognized that stimulation of osteoclasts by agents such as parathyroid hormone (PTH) occurs through a hormonal interaction with osteoblastic cells, which are thereby induced to activate osteoclasts. To determine whether TRANCE accounts for this activity, we tested its effects on mature osteoclasts. TRANCE rapidly induced a dramatic change in osteoclast motility and spreading and inhibited apoptosis. In populations of osteoclasts that were unresponsive to PTH, TRANCE caused activation of bone resorption equivalent to that induced by PTH in the presence of osteoblastic cells. Moreover, osteoblast-mediated stimulation of bone resorption was abrogated by soluble TRANCE receptor and by the soluble decoy receptor osteoprotegerin (OPG), and stimulation of isolated osteoclasts by TRANCE was neutralized by OPG. Thus, TRANCE expression by osteoblasts appears to be both necessary and sufficient for hormone-mediated activation of mature osteoclasts, and TRANCE-R is likely to be a receptor for signal transduction for activation of the osteoclast and its survival.

Induction of osteoclast formation by parathyroid hormone depends on an action on stromal cells

It is believed that parathyroid hormone (PTH) increases the resorptive activity of pre-existing osteoclasts through a primary interaction with cells of the osteoblastic lineage. Much less is known, however, of the mechanisms by which PTH induces osteoclast formation. It is known that osteoclast formation occurs through a contact-dependent interaction between stromal cells and haemopoietic precursors, but it is not known whether PTH acts on stromal cells or precursors to induce osteoclast formation. To address this issue, we compared the ability of haemopoietic cultures to generate osteoclasts, identified as calcitonin receptor positive (CTRP) cells, and to resorb bone in response to PTH and 1,25(OH)2 vitamin D3 (1,25(OH)2D3). We found that when murine haemopoietic tissues were incubated at densities sufficiently high to support haemopoiesis, both PTH and 1,25(OH)2D3 induced bone resorption in bone marrow cells, but in cultures of haemopoietic spleen only 1,25(OH)2D3 induced CTRP cells, and neither hormone induced bone resorption. To determine whether these differences were attributable to differences in stromal cells or haemopoietic precursors, lower densities of haemopoietic spleen cells were incubated on osteoblastic (UMR 106), splenic or bone marrow stromal cells. We found that the behaviour of the cocultures reflected the characteristics and origin of the stromal cells. Thus, the ability of both osteoblastic and splenic stromal cells to induce CTRP cells with 1,25(OH)2D3, while only osteoblastic cells induced osteoclasts with PTH, from the same precursors, suggests that the ability of PTH to induce osteoclastic differentiation cannot be attributed to a hormonal action on osteoclast precursors, but depends on a response in stromal cells.

Parathyroid hormone induces bone resorption in human peripheral blood mononuclear cells

Osteoclasts are known to derive from a macrophage colony-stimulating factor (M-CSF)-dependent precursor shared with macrophages. Cells capable of forming osteoclasts are present in peripheral blood. We characterized this population by incubating human peripheral blood mononuclear cells (PBMCs) with osteoclast-inductive UMR 106 cells, human macrophage colony stimulating factor (hM-CSF) and parathyroid hormone (PTH) or 1.25(OH)2 vitamin D3 on slices of devitalised cortical bone. We found that PBMCs were capable of substantial bone resorption, to levels comparable to those of haemopoietic tissue. Cells plated at very low densities and screened for the presence or absence of excavations revealed a linear relationship (r = 0.994) between the number of cells plated and the number of excavations formed. The limiting dilution analysis suggested that 1 in every 300-600 plated cells (0.15-0.3% of the PBMC population) had the capacity to resorb bone. The precursor was found in the rapidly adherent fraction, and typically generated very small numbers of excavations, suggesting that it was a relatively mature cell type. Co-cultures of PBMCs with UMR 106 cells would not generate osteoclasts without PTH/1.25(OH)2 vitamin D3, even with M-CSF, indicating that osteoclast-induction by stromal cells is not attributable to hormonal induction of M-CSF in UMR 106 cells, but that PTH induces some other activity, necessary for osteoclast but not macrophage formation, in UMR 106 cells. Osteoclasts did not form if PTH was omitted in the first few days of the culture period. Thus, osteoclasts appear to form not from cells committed to macrophage differentiation, but from a discrete subpopulation of relatively mature bipotential or osteoclast-committed precursors which, in the absence of an osteoclast-inductive stimulus, become irreversibly lost to the osteoclast lineage.

Adult females and pubic bone growth

Previous research (Tague [1994] Am. J. Phys. Anthropol. 95:27-40) has shown an age effect in pubic bone length among adult women. Tague found that in three prehistoric Native American skeletal samples, women aged 18-24 had a significantly shorter linea terminalis than did women aged 25 and older. The purpose of this research is to determine whether such a difference can be discerned in other female skeletal samples. Three female skeletal samples were used in this analysis: 75 African-American and 42 European-American females aged 18-39 from the Hamann-Todd Collection (collected between 1893 and 1938; Iscan, 1990) and 99 African-American females aged 18-39 from the Terry Collection (collected between 1914 and 1965; Cobb, 1933; Iscan, 1990). Several chord measurements of pubic bone length along the linea terminalis were analyzed by one-tailed t-tests of the separate samples subdivided into two age groups: 18-24 and 25-39 years. Of 15 comparisons between age groups, none differed significantly by age group within each sample. It is concluded that the observed significant difference in pubic bone length in the Native American female skeletal samples cannot be replicated in other samples and that there is no age effect on pubic bone length in the samples tested in this analysis. Tague's findings reflect either the occurrence of late menarche in prehistoric populations or differential survivorship.

Identification and characterization of the murine Rag1 promoter

Rag1 and Rag2 are required for the somatic rearrangement of immunoglobulin genes and T-cell receptor genes and the subsequent development of B and T cells. We describe the pattern of DNase I hypersensitive sites surrounding the Rag1 gene that accompanies mouse B-cell development and show that one of these sites corresponds to the murine Rag1 promoter. Transcription initiates over a 30 bp region, with approximately 70% of the transcripts initiating within a 5 bp region. The promoter contains neither a consensus TATA box nor an initiator, but does contain an AT rich sequence that could serve as a non-consensus TATA box. The Rag1 promoter directs only negligible levels of expression in transient transfection assays, but when combined with a heterologous enhancer, it is capable of driving significant levels of expression in pre-B cells, pre-T cells, and mature B cells. Methylation interference and mutation analysis reveal that the Rag1 promoter contains binding sites for E-box binding proteins, NF-Y proteins, and Ikaros proteins. These findings are discussed with respect to B-cell development and regulation of differential Rag expression by the promoter in pre-B, pre-T, and CNS cells.

Osteoclast activation: potent inhibition by the bisphosphonate alendronate through a nonresorptive mechanism

Alendronate, an aminobisphosphonate used in the treatment of osteoporosis, is a potent inhibitor of bone resorption. Its mechanism of action is unknown. Because it localizes to bone surfaces, we compared the sensitivity of components of the resorptive process to incubation on alendronate-coated bone surfaces. We found that bone resorption by osteoclasts isolated from neonatal rat bone was unaffected by alendronate (10(-4) M). Osteoclast production in bone marrow cultures, as assessed by the production of calcitonin-receptor positive cells, was observed even at 10(-4) M, but bone resorption in these cultures was almost completely abolished by 10(-5) M alendronate. The greater sensitivity of osteoclast activation to inhibition by alendronate that these results suggest was supported by similar inhibition of osteoblast-mediated activation of osteoclasts from neonatal rat bone. Thus, activation of osteoclasts by osteoblastic/stromal cells is apparently the most sensitive component of the pathway whereby bone resorption is affected. Moreover, the ability of alendronate to suppress osteoclastic activation does not depend on resorption-mediated release of alendronate from bone surfaces. This ability extends the range of cell types and processes that might be affected by alendronate, beyond those in the immediate vicinity of resorbing cells, to include any cell that comes into contact with alendronate-coated bone surfaces.

Hookworm: not a pre-Columbian pathogen

It has been asserted that evidence of pre-Columbian hookworm has been found in the Americas, specifically in Peru, Brazil, and Tennessee. However, based on an analysis of the life cycle and morphology of hookworm, the paleopathologic indications for the presence of hookworm infestation in the Americas prior to 1492 are suspect. It is concluded that the material found in the Peruvian mummy is probably pinworms, that the Brazilian and Tennessee materials are probably not hookworm, and, therefore, that hookworm was one of many pathogens brought to the Americas after contact in 1492.

Analysis of the probability of multiple taxa in a combined sample of Swartkrans and Kromdraai dental material

It has been argued (Grine, [1988] Evolutionary History of the "Robust" Australopithecines [New York. Aldine de Gruyter], pp. 223-243) that the australopithecine material from Swartkrans and Kromdraai represents distinct species. In an attempt to test the validity of separate taxa at Swartkrans and Kromdraai, Cope's (Cope [1989] Systematic Variation in Cercopithecus Dental Samples [Austin: University of Texas]) method of analysis was adapted and utilized. This procedure includes an analysis of the coefficients of variation (CVs) of the individual posterior teeth (buccal-lingual breadth) of a combined fossil sample compared with the CVs of several known single taxon reference groups. The Cope and Lacy (Cope and Lacy [1992] Am. J. Phys. Anthropol. 89:359-378) stimulation technique was also employed in the analysis. Based on these analyses, there is no justification for a taxonomic separation between the australopithecine material from Swartkrans and Kromdraai. Therefore, the assertion that the Swartkrans and Kromdraai material represent two distinct species is not indicated by the available dental metric evidence.

Presence of hsp65 in bacterial extracts (OM-89): a possible mediator of orally-induced tolerance?

Heat shock proteins (HSP) have been implicated in rodent models of autoimmunity, particularly arthritis, and there is suggestive though inconclusive evidence that they may also play a role in human autoimmune disease. The simplest hypothesis is based on molecular mimicry due to the amino-acid sequence homology between mammalian and microbial HSP. Recently OM-89, an extract of several strains of Escherichia coli, has shown some efficacy in the treatment of rheumatoid arthritis (RA) when taken orally. Using species-specific antibodies, we show here that OM-89 contains the 65 kDa HSP (hsp65), while hsp65 was not detected in another bacterial extract containing other microorganisms, including Staphylococcus aureus (OM-85). We suggest that if the human homologue of hsp65 is a relevant target antigen in the human disease, the efficacy of the preparation could be due to induction of oral tolerance or to switching the Th1 response towards Th2. Alternatively, even if the human hsp65 is not a target molecule in RA joints, OM-89 may evoke bystander suppression of joint inflammation via induction of TGF beta-secreting effector cells. These hypotheses should be tested in further studies.

Geropsychiatric Public Sector Nursing: Placement Challenges

1. The nursing home eligible resident, who has experienced long periods of institutional living in state hospitals and many unsuccessful placements in nursing home facilities, presents a challenge in developing a viable community treatment plan. 2. Mental health consultations with nursing home staff are valuable resources for developing and implementing additional behavioral management interventions. 3. Collaborative efforts of public sector health care agencies have resulted in a cost effective approach to decreasing hospital admissions and recidivism and increasing community tenure of geropsychiatric residents.

The effect of hepatocyte growth factor on the behaviour of osteoclasts

Hepatocyte growth factor (HGF) stimulates the growth, motility and morphogenesis of a variety of cell types, including hemopoietic progenitors. We found that HGF is a potent inhibitor of bone resorption by isolated rat osteoclasts. However, in the presence of the osteoblastic cell line UMR 106, it stimulated osteoclastic resorption. HGF also increased osteoclastic motility and spread area, over a similar concentration range. We detected no effect on osteoclast formation or survival. Our data suggest that HGF may be involved in the recruitment of osteoclasts to sites of bone resorption, but that during migration resorptive functions are suppressed. Once on resorptive sites, the osteoclast response to HGF is modulated by osteoblastic cells and the bone resorptive activity of osteoclasts may be stimulated accordingly.

Macrophage inflammatory protein-1 alpha and IL-8 stimulate the motility but suppress the resorption of isolated rat osteoclasts

Cells of the osteoblastic lineage play a major role in the regulation of osteoclastic bone resorption. Recent studies have demonstrated production of chemokines by osteoblastic cells. Although these phagocyte-stimulating and proinflammatory cytokines act as chemoattractants and activators for other members of the hemopoietic lineage, their actions on osteoclasts have not been characterized. We found that macrophage inflammatory protein-1 alpha (MIP-1 alpha) and IL-8 inhibited bone resorption by rat osteoclasts, primarily through reduction in the proportion of osteoclasts resorbing bone, a pattern of inhibition previously observed in response to macrophage CSF (M-CSF). MIP-2, RANTES, MIP-1 beta, and monocyte chemotactic protein-1 were without effect on resorption. MIP-1 alpha and IL-8, but not the other chemokines, also stimulated osteoclastic motility and increased the osteoclast spread area in a dose-dependent manner, over the same concentration range as that which inhibited bone resorption. In addition, MIP-1 alpha induced osteoclast orientation in a gradient of the chemokine, and stimulated osteoclast migration. We detected no effect of chemokines on osteoclast formation or survival. Our data suggest that chemokines can promote osteoclast orientation and migration, processes that might be involved in chemotaxis; it seems appropriate that resorptive functions should be suppressed during migration. Because chemokines are proinflammatory, their actions on osteoclasts might represent mechanisms by which bone resorption is modulated by the inflammatory process when this occurs in bone. However, given that chemokines are increasingly recognized to be multifunctional and that they are produced by cells of the osteoblastic lineage, they may also be components of the physiologic regulation of bone resorption.

Localisation of mRNA for collagenase in osteocytic, bone surface and chondrocytic cells but not osteoclasts

Osteoclasts resorb the extracellular matrix of bone by secreting protons and enzymes into a circumpherentially sealed compartment between the osteoclast and the bone surface. Although the lysosomal cysteine proteinases play a major role in matrix degradation by osteoclasts, collagenase (matrix metalloproteinase-1, EC 3.4.24.7) is also required for osteoclastic bone resorption, and may be directly involved in collagen degradation in the hemivacuole. We assessed the effects of inhibitors of cysteine proteinases and collagenase on bone resorption by osteoclasts isolated from rodent bone. We found that while inhibition of cysteine proteinases strongly suppressed osteoclastic resorption, inhibitors of collagenase were without effect on the number, size, or demineralised fringe of excavations. We could find no evidence of expression of mRNA for collagenase in rat osteoclasts by in situ hybridisation, but found that it was expressed by chondrocytes, bone surface cells and osteocytes adjacent to osteoclasts. The distribution of these cells, and the correlation between increased collagenase production and increased stimulation of osteoclastic resorption in vitro by bone cells, suggests that these cells might be involved in the regulation of bone resorption in situ, and that collagenase production might play a role in this process.

Macrophage inflammatory protein-1 alpha and IL-8 stimulate the motility but suppress the resorption of isolated rat osteoclasts

Cells of the osteoblastic lineage play a major role in the regulation of osteoclastic bone resorption. Recent studies have demonstrated production of chemokines by osteoblastic cells. Although these phagocyte-stimulating and proinflammatory cytokines act as chemoattractants and activators for other members of the hemopoietic lineage, their actions on osteoclasts have not been characterized. We found that macrophage inflammatory protein-1 alpha (MIP-1 alpha) and IL-8 inhibited bone resorption by rat osteoclasts, primarily through reduction in the proportion of osteoclasts resorbing bone, a pattern of inhibition previously observed in response to macrophage CSF (M-CSF). MIP-2, RANTES, MIP-1 beta, and monocyte chemotactic protein-1 were without effect on resorption. MIP-1 alpha and IL-8, but not the other chemokines, also stimulated osteoclastic motility and increased the osteoclast spread area in a dose-dependent manner, over the same concentration range as that which inhibited bone resorption. In addition, MIP-1 alpha induced osteoclast orientation in a gradient of the chemokine, and stimulated osteoclast migration. We detected no effect of chemokines on osteoclast formation or survival. Our data suggest that chemokines can promote osteoclast orientation and migration, processes that might be involved in chemotaxis; it seems appropriate that resorptive functions should be suppressed during migration. Because chemokines are proinflammatory, their actions on osteoclasts might represent mechanisms by which bone resorption is modulated by the inflammatory process when this occurs in bone. However, given that chemokines are increasingly recognized to be multifunctional and that they are produced by cells of the osteoblastic lineage, they may also be components of the physiologic regulation of bone resorption.

The role of reactive oxygen intermediates in osteoclastic bone resorption

Osteoclasts have been shown to produce reactive oxygen intermediates (ROI) and it has been suggested that ROI are involved in the process of bone resorption. ROI have also been shown to play a central role in the activation of the multisubunit transcription factor NF-kappa B that enhances the transcription of genes encoding defence and signaling proteins. Therefore, we have assessed the effect of pyrrolidine dithiocarbamate (PDTC), an oxygen-radical scavenger and metal chelator that is a selective and potent inhibitor of NF-kappa B activation, on osteoclastic bone resorption in the bone slice assay. PDTC (0.001-0.1 mM) dose-dependently and non-cytotoxically inhibited osteoclast activity with an IC50 of 0.01 mM. PDTC (0.01 mM) caused no change in the ratio of resorption pit area to resorption pit depth as measured by Lasertec confocal microscopy, indicating that ROI are not involved in the resorptive process per se. This view is supported by time-course studies showing that addition of PDTC or N-acetyl cysteine (NAC; an ROI scavenger, but not metal chelator), 6 hr after the start of the assay had no significant effect on subsequent bone resorption. Desferal (100 microM), a chelator of iron and other metal ions, had no significant effect on bone resorption, indicating (along with the results with NAC) that ROI-scavenging rather than metal chelation is responsible for inhibition of osteoclastic bone resorption by PDTC. Taken together these results indicate that ROI produced by osteoclasts in the bone slice assay are not involved in the process of bone resorption, but are important during osteoclast activation for bone resorption, possibly being involved in activation of the transcription factor NF-kappa B.

Improving postural control through integration of sensory inputs and visual biofeedback

Postural control is an essential component to be considered in the rehabilitation of stroke survivors. This article attempts to provide the clinician with terminology and frameworks for classification in order to provide a more focused intervention. There is a comparison of some of the available assessments of impairment and disability. Treatment emphasizing the specific use of visual biofeedback to improve postural control is described. Control of the sensory environment during treatment to challenge a patient's ability to integrate available sensory information to perform balance activities is described. A case study incorporating treatment ideas is included.

Protective effects of hsp70 in inflammation

Inflammation results from the recruitment to a given tissue or organ and the activation of leucocytes, among which the monocytes-macrophages play a major role. These phagocytic cells produce high levels of reactive oxygen species (ROS) as well as cytokines. Whereas both ROS and cytokines have the potential to regulate the expression of heat shock (HS)/stress proteins (HSP), it appears that these proteins in turn have the ability to protect cells and tissues from the deleterious effects of inflammation. The mechanisms by which such protection occurs include prevention of ROS-induced DNA strand breaks and lipid peroxidation as well as protection from mitochondrial structure and function. In vivo, HS protects organs against a number of lesions associated with the increased production of ROS and/or cytokines. In an animal model for adult respiratory distress syndrome, an acute pulmonary inflammatory condition, HS completely prevented mortality. HSP (hsp70 in particular) may also exert protective effects in the immune system by contributing to the processing and presentation of bacterial and tumoral antigens. The analysis of the expression of hsp70 may prove of diagnostic and prognostic value in inflammatory conditions and therapeutical applications are being considered.

Large-scale production and characterization of recombinant human immunodeficiency virus type 1 Nef

Sequences encoding the 27K and 25K nef gene products (Nef 27 and Nef 25) were amplified by PCR from a human immunodeficiency virus type 1 infectious clone and subcloned directly into Escherichia coli, yeast and baculovirus expression vectors. The yeast- and baculovirus-derived Nef had native N termini but the expression levels were low. The expression levels of the E. coli-derived glutathione S-transferase-Nef fusion proteins were very high and a major portion was soluble. Large-scale production of E. coli-derived Nef 27 and Nef 25 was carried out by growing recombinant cells in a fermenter under fed-batch conditions followed by affinity purification on glutathione-Sepharose before and after thrombin cleavage. Large quantities of highly purified recombinant Nef proteins have been produced for functional and structural studies. Under non-reducing conditions both Nef 27 and Nef 25 existed as a mixture of monomers, dimers and small amounts of higher oligomers, but when reduced were monomeric. The highly purified Nef proteins had no G protein activities, however Nef 27 was biologically active. When electroporated into uninfected CD4+ T lymphocytes both E. coli-derived Nef 27 and yeast-derived myristylated Nef 27 down-regulated the surface expression of CD4, demonstrating that this method can be used to assess the biological activity of purified recombinant Nef.

Automated three-dimensional characterization of osteoclastic resorption lacunae by stereoscopic scanning electron microscopy

The use of stereoscopic scanning electron microscopy to analyze quantitatively the topography of excavations made by osteoclasts in slices of devitalized cortical bone was evaluated. Using this innovative technique, the need mechanically to tilt the specimen stage to gather three-dimensional information is obviated by instead tilting the electron beam both to produce real-time stereo pairs and to gather measurement data. Based on the comparison of two images of microscopic areas, cross-correlation is used to determine the image shift between the features in the stereo pair. This information is then used dynamically to correct the height of the tilt axis and lens focus in a feedback loop, generating a quantitative measurement of height difference. With this approach, relative heights of individual points, line profiles, area topography maps, and three-dimensional reconstructions of excavations were obtained rapidly and at high resolution. This approach combines the advantage in topographic data acquisition of confocal microscopy with the advantages of the increased resolution and focal depth of scanning electron microscopy (SEM). The technique should facilitate not only the topographic analysis of osteoclastic excavations in bone slices at high resolution but also the three-dimensional analysis of the structure of bone tissue.

Macrophage colony-stimulating factor stimulates survival and chemotactic behavior in isolated osteoclasts

Macrophage colony-stimulating factor (M-CSF) is known to play an important role in osteoclast formation. However, its actions on mature cells have not been fully characterized. We now report that M-CSF dramatically stimulates osteoclastic motility and spreading; osteoclasts responded to a gradient of M-CSF with orientation, and random cell polarization occurred after isotropic exposure. M-CSF also supported the survival of osteoclasts by preventing apoptosis. Paradoxically, M-CSF inhibits bone resorption by isolated osteoclasts. We found that this was effected predominantly by reduction in the number of excavations. Thus, M-CSF showed a propensity to suppress resorption through a reduction in the proportion of cells that were resorbing bone. Our data suggest that apart from the established role of M-CSF in the provision of precursors for osteoclastic induction, a major role for M-CSF in bone resorption is to enhance osteoclastic survival, migration, and chemotaxis. It seems appropriate that during these processes resorptive functions should be suppressed. We suggest that M-CSF continues to modulate osteoclastic activity once osteoclasts are on resorptive sites, through regulation of the balance between resorption and migration, such that not only the quantity, but the spatial pattern of resorption can be controlled by adjacent M-CSF-secreting cells of osteoblastic lineage.

Purification and characterization of a tripeptidyl peptidase I from human osteoclastomas: evidence for its role in bone resorption

Tripeptidyl peptidase I (EC 3.4.14.9), which cleaves tripeptides from the N-terminus of synthetic substrates, has been purified from human osteoclastomas (a bone tumor containing large numbers of normal osteoclasts). The enzyme has an M(r) of 48 kDa but forms aggregates with an M(r) of about 700 kDa. The tripeptidyl peptidase has an acidic pH optimum (approximately pH 5.0), suggesting that it has a lysosomal localization and prefers substrates with a hydrophobic amino acid in the P1 position. There is an absolute requirement for a nonsubstituted N-terminus. The enzyme is inhibited by reagents which modify serine and histidine residues. Lysosomal tripeptidyl peptidase is known to be capable of cleaving Gly-Pro-X triplets from synthetic collagen-like polypeptides. Ala-Ala-Phe-CH2Cl, a potent inhibitor of osteoclastoma tripeptidyl peptidase, inhibits osteoclastic bone resorption in an in vitro test system. This suggests that tripeptidyl peptidase I, secreted by osteoclasts, is involved at some stage in the degradation of bone collagen.