Implicit theories of the body among college women: implications for physical activity

This study explored the relationship between implicit theories of the body (ITB) and self-reported physical activity. ITB are beliefs about the malleability of the body. Individuals may hold entity ITB (that body appearance is fixed) or incremental ITB (that body appearance can be changed). Female undergraduate students (N = 313) completed an online survey assessing ITB, physical activity, and discrepancy between actual and ideal body weight. Participants endorsing incremental ITB reported more physical activity. A significant ITB by weight discrepancy interaction emerged. Developing interventions targeting implicit theories of the body may be one way to increase physical activity.

Web 2.0 for health promotion: reviewing the current evidence

As Web 2.0 and social media make the communication landscape increasingly participatory, empirical evidence is needed regarding their impact on and utility for health promotion. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we searched 4 medical and social science databases for literature (2004-present) on the intersection of Web 2.0 and health. A total of 514 unique publications matched our criteria. We classified references as commentaries and reviews (n = 267), descriptive studies (n = 213), and pilot intervention studies (n = 34). The scarcity of empirical evidence points to the need for more interventions with participatory and user-generated features. Innovative study designs and measurement methods are needed to understand the communication landscape and to critically assess intervention effectiveness. To address health disparities, interventions must consider accessibility for vulnerable populations.

Cutaneous papillomavirus E6 oncoproteins associate with MAML1 to repress transactivation and NOTCH signaling

Papillomavirus E6 oncoproteins associate with LXXLL motifs on target cellular proteins to alter their function. Using a proteomic approach, we found the E6 oncoproteins of cutaneous papillomaviruses Bovine Papillomavirus Type 1 (BE6) and HPV types 1 and 8 (1E6 and 8E6) associated with the MAML1 transcriptional co-activator. All three E6 proteins bind to an acidic LXXLL motif at the carboxy-terminus of MAML1 and repress transactivation by MAML1. MAML1 is best known as the co-activator and effector of NOTCH induced transcription, and BPV-1 E6 represses synthetic NOTCH responsive promoters, endogenous NOTCH responsive promoters, and is found in a complex with MAML1 in stably transformed cells. BPV-1 induced papillomas show characteristics of repressed NOTCH signal transduction, including suprabasal expression of integrins, talin, and basal type keratins, and delayed expression of the NOTCH dependent HES1 transcription factor. These observations give rise to a model whereby papillomavirus oncoproteins including BPV-1 E6 and the cancer associated HPV-8 E6 repress Notch induced transcription, thereby delaying keratinocyte differentiation.

STUDIES ON THE HEMOLYTIC STREPTOCOCCUS OF HUMAN ORIGIN : I. OBSERVATIONS ON THE VIRULENT, ATTENUATED, AND AVIRULENT VARIANTS

1. Four common variants of the hemolytic streptococcus of human origin have been described. These have been designated the F, M, attenuated M, and C variants. 2. The F and M variants only have been isolated from the blood stream in streptococcal infections. Only the M, however, has any primary virulence for the mouse. 3. Both these variants resist phagocytosis in human blood under suitable conditions, and this appears to be a reliable test for human virulence. 4. The attenuated M variant, found only in laboratory cultures, has a capsule as well developed as that of the virulent variants, and yet does not resist phagocytosis. 5. The C variant has no capsule and is readily phagocyted. It appears to correspond to the avirulent variant in other species. 6. An attempt has been made to correlate these four variants with those already described in the literature. 7. The application of these findings to the problem of virulence has been discussed.

STUDIES ON THE HEMOLYTIC STREPTOCOCCUS OF HUMAN ORIGIN : II. OBSERVATIONS ON THE PROTECTIVE MECHANISM AGAINST THE VIRULENT VARIANTS

1. Anantiserum which specifically protects mice against a virulent culture (M variant) of the hemolytic streptococcus contains specific opsonin. Phagocytosis of the organisms can be observed in the peritoneum of the protected mouse. 2. An antiserum prepared by injecting an animal with the living M variant specifically opsonizes both the F and the M variant of the strain. 3. Evidence is presented which indicates the probable identity of the specific opsonin and the anti-M precipitin of Lancefield (7). Agglutination appears to be dependent upon a different antibody. 4. It is possible to type the hemolytic streptococci by means of specific opsonins, and the opsonic method has certain advantages over agglutination, precipitation, and mouse protection tests. It is evident from what little has been done that there are many types. 5. The serum of infants contains no opsonin for the virulent hemolytic streptococci, but the serum of adults may contain specific opsonins for certain strains. Inasmuch as no opsonins were demonstrable in two polyvalent antibacterial sera examined, the possibilities of therapeutic transfusion are discussed.

Pulmonary Orthopoxvirus infection compromises a murine OVA peptide immune response in a dose-dependent manner (39.8)

Cowpox virus (CPXV), a close relative of variola virus that causes smallpox, can suppress the immune system through a large array of immunosuppressive gene products. We developed a murine model in which DO11.10 T cells specific for an OVA peptide were transferred into BALB/c mice to assess the impact of a pulmonary CPXV infection on DO11.10 T cell proliferation in lung draining lymph nodes following intranasal OVA peptide delivery. High and low-dose CPXV infections were compared. Both doses lead to clinical illness, but the high dose is lethal. A high-dose infection reduced DO11.10 T cell proliferation, but a low-dose infection did not. At the time that proliferation of T cells was assessed (6d),15±1% of lung dendritic cells (DCs) were infected at the high-dose, but only 5±1% of DCs at the low-dose. At both doses, infected and uninfected DCs had decreased expression of co-stimulatory molecules. We speculated that the lung microenvironment created by infection, rather than direct infection of the DCs, suppressed DC immune function. In support, we found that bronchoalveolar lavage fluid and supernatant derived from lung homogenates from infected mice suppressed the function of uninfected lung DCs in vitro. Furthermore, the suppressive activity was more highly concentrated in lungs from high-dose infected mice. These studies strongly suggest that orthopoxvirus infections create an immunosuppressive microenvironment that compromises the host pulmonary immune responses.

A decade of stigma and discrimination in mental health: plus ça change, plus c'est la même chose (the more things change, the more they stay the same)

In recent years, efforts to combat stigma and discrimination experienced by mental health service users have ranged from small local initiatives to national and international campaigns. Success has been mixed, with significant, lasting benefits appearing to be elusive. This paper explores the current nature and extent of stigma and discrimination in an area of the north of England and compares findings with those from a study undertaken a decade previously in 1997. Qualitative responses to a postal questionnaire received in 2007 were thematically analysed and compared and contrasted with findings from the 1997 study. Four broad categories of discrimination--(1) employment; (2) professional; (3) communities; and (4) family and friends--arose from the 2007 data, the most common being discrimination in employment. There were close similarities in both sets of data. Stigma and discrimination remain largely as strong, damaging and enduring as they were a decade ago. A range of pre-emptive interventions that support people prior to the escalation of mental health crises could limit the impact of stigma.

An educational evaluation of supervisor and mentor experiences when supporting primary care graduate mental health workers

This paper reports on the findings of a postal survey used to enhance understanding into the backgrounds, experiences and support offered to supervisors and mentors of Primary Care Graduate Mental Health Workers (PCGMHWs). A postal questionnaire was sent to the total population of supervisors and mentors who had supported PCGMHW students from three universities in the Northwest of England, during the period of their introduction 2004-2006. Most supervisors and mentors had previous experience of supervision and mentorship with other types of students but not PCGMHWs. Data suggest that there were difficulties due limited understanding of the role of PCGMHWs and how it was to be operationalized. Respondents reported staff shortages, time constraints and competing commitments, which limited support available to students. The lack of organizational readiness and infrastructure to support the role was widely reported. However, the role has developed and is generally well received. The implications for future development of the PCGMHW and the preparation and support of supervisors and mentors are discussed.

Mental health crisis and respite services: service user and carer aspirations

There is emerging evidence that crisis resolution services can provide alternatives to hospital admission, reducing demand on inpatient beds. Following a public consultation exercise in Lancashire (England), a team of nurses undertook a study, using interactive research methodology, to gain an understanding of how users and carers define a crisis and what range of crisis services, resources and interventions service users and carers thought would help avoid unnecessary hospital admission. Data collection comprised postal questionnaires and 24 group meetings with service users and carers, which were held during 2006. Data were analysed, and seven themes were identified: (1) definitions of a crisis; (2) access to services; (3) interventions; (4) range of services required (before, during and after crisis); (5) place of treatment; (6) recovery and rehabilitation; and (7) community support. We conclude that expressed preferences of service users and carers for pre-emptive services that are delivered flexibly will present a challenge for service commissioners and providers, particularly where stringent access criteria are used. Home-based pre-emptive services that reduce the need for unnecessary hospital treatment may avoid progression to social exclusion of service users.

The Mental Capacity Act 2005: implications for dietetic practice

The Mental Capacity Act (MCA) 2005 will be implemented in England and Wales in 2007 and have consequences for dietitians who work with people who may lack capacity to make specific decisions. This paper will explore issues arising from the introduction of the Act and considers the implications for dietitians involved in the delivery of clinical care, using enteral feeding as an illustrative example. If patients lack capacity to make specific decisions, dietitians will be required to record if, how and why they reached a decision, how they are involved in the decision making process and need to be able to justify their actions in relation to those decisions. This paper discusses the importance of dietitians' involvement in best interests decision making and considers the implications of decision making where people have drawn up a Lasting Power of Attorney. The role of such advance decisions is discussed and consideration is given to the potential compatibility of perspectives between the patient and family that may give rise to disputes. Dietitians may be well placed within multidisciplinary team working to ensure patients and their carers are part of the decision making process through effective communication and support for patients. Dietitians in England and Wales must consider the implications of the MCA upon their clinical practice and others outside these jurisdictions may like to reflect on the relevance of such developments in their own contexts.

Origins and consequences of mitochondrial decline in nucleated erythrocytes

Cellular aging in nucleated erythrocytes from lower vertebrates is accompanied by losses in mitochondria but it remains unclear (i) how these losses accrue (ii) if these changes alter energetics and (iii) whether such changes increase the propensity for apoptosis. We addressed these questions using trout erythrocytes that were separated into age classes using inherent differences in buoyant density. The oldest cells showed a profound decline in mtDNA transcripts, due to reductions in both transcription (90% decline in total RNA) and mtDNA copy number (35%). No alterations in the ratio of 16S rRNA to COX I mRNA were detected, nor was there an accumulation of unprocessed mtDNA transcripts. While older cells had reduced basal respiration, there were no changes in mitochondrial enzymes stoichiometries, tissue ATP levels or dinitrophenol-induced (maximal) respiration rates. Apoptosis could not be induced in either whole blood, young or old erythrocytes by pro-oxidants, mitochondrial inhibitors or staurosporine. In contrast, cyclosporin A (CsA) caused caspase 3 activation, DNA laddering and LDH leakage, but only in young cells. Both CsA and a combination of azide, oligomycin and dinitrophenol cause mitochondrial depolarization and caspase 9 activation, but only CsA induced caspase 3 and apoptosis. Caspase inhibitor studies support the conclusion that mitochondrial changes may accompany CsA-induced cell death, but are not essential in its progression. While pifithrin failed to induce cell death, it enhanced the effects of CsA, implicating a role for p53. Collectively, these studies suggest that the mitochondrial changes with aging do not compromise cellular function, although trout erythrocytes can initiate apoptosis by non-mitochondrial pathways.

Renal-coloboma syndrome: prenatal detection and clinical spectrum in a large family

Renal-coloboma syndrome includes abnormalities in the urogenital and ocular systems as its primary manifestations, although it can be associated with abnormalities in other systems as well. This syndrome is caused by mutations in the PAX2 gene and is transmitted as an autosomal dominant trait. We report a family in which at least 7 members have manifestations of renal-coloboma syndrome, including two in whom renal disease was diagnosed prenatally by ultrasound examination. A pathogenic frame-shift mutation (619insG) was found in the PAX2 gene in affected family members, who show remarkable variability in both the ocular and renal manifestations of the syndrome.

Evidence for changing guidelines for routine screening for retinopathy of prematurity

CONTEXT

Existing guidelines recommended by the Canadian Pediatric Society (CPS) and American Academy of Pediatrics (AAP) for routine screening for retinopathy of prematurity (ROP) remain controversial.

OBJECTIVE

To determine whether current guidelines for routine screening for ROP should be changed.

DESIGN

We examined data that were collected as part of a larger study of 14 neonatal intensive care units (NICUs) in Canada. We examined the effect of strategies using different birth weight (BW) and gestational age (GA) criteria for routine ROP screening, and performed a cost-effectiveness analysis.

SETTING

The 14 NICUs (except one) are regional tertiary level referral centres serving geographic regions of Canada, and include approximately 60% of all tertiary-level NICU beds in Canada.

PATIENTS

This large cohort included all 16 424 infants admitted to 14 Canadian NICUs from January 8, 1996, to October 31, 1997.

INTERVENTIONS

None.

MAIN OUTCOME MEASURE

Treatment for ROP.

RESULTS

The most cost-effective strategy was to routinely screen only infants having a BW of 1200 g or less. This included all infants treated for ROP (except 1 outlier at 32 weeks GA and 1785 g BW), at a marginal cost per additional person with improved vision of $513 081 for screening patients between 28 weeks GA and 1200 g BW, compared with $1 800 039 and $2 075 874 for using the current AAP and CPS guidelines, respectively (cryotherapy outcomes). Results for laser therapy were similar, but costs were slightly lower. This strategy reduced the number of infants screened under the current CPS guidelines by 46%.

CONCLUSION

Screening only infants having a BW of 1200 g or less is the most cost-effective strategy for routine ROP screening.

Bartonella henselae infection in British Columbia: evidence for an endemic disease among humans

Human bartonellosis in North America is mainly associated with Bartonella henselae, and the availability of laboratory diagnostic tools has significantly heightened awareness of the spectrum of human disease that is caused by this bacterium. We detail herein examples of illness in a pediatric population which serve to confirm that B. henselae-associated disease exists in British Columbia. Seroprevalence studies among asymptomatic adults and among children with symptomatic respiratory illness of other causation demonstrated that 36.8% and 18.5% of sera, respectively, had IFA-IgG titres > or = 1:256. IFA-IgG titres did not vary significantly whether B. henselae ATCC 49793 or a local wild-type B. henselae isolate were used as substrate. An assessment of IgM response was consistent with the proposal that endemic seroprevalence is a function of past rather than recent exposure. Both clinical and serological studies are concordant in providing evidence that B. henselae is endemic in British Columbia.

Suicide risk assessment: a review of procedures

Suicide risk assessment is an important part of the nurse's role. Suicide screening is an integral component of the assessment process. It should be systematic and follow a prescribed procedure: client self assessment, holistic assessment and diagnosis. The Gatehouse Assessment Centre in Warrington, UK, a predominantly nurse led centre, was opened in 1995, operates 365 days, 9 am till 9 pm, with open referral. The Centre offers psychiatric assessment, short-term treatments or referral on without hospital beds. In line with local and national policy, the Gatehouse team have introduced suicide rating scales as part of their risk screening process. However, the team have encountered problems using their designated scale, adapted from the Suicide Intent Scale, Pierce (1981). The major problem with the use of a rating scale was that, as a one off scoring system, it did not reflect the dynamic nature of suicidal behaviour. Furthermore, it is questionable whether a tool developed for research purposes would be used in the same way in practice. From a clinical perspective, the tool was capable of measurement only and failed to assist a dynamic holistic assessment required by practitioners. It was, therefore, necessary to review and evaluate the risk assessment procedure. In order to address these problems an assessment procedure which is more than a once only 'score' was piloted. The procedure incorporated risk screeners. Rather than rely on a value weighting system, or a positive or negative conclusion, it took account of the continuum of risk which is contingent on a broad range of factors. It took account of the accumulation of risk factors which may be increased or reduced in the light of unfolding events. Details of the new procedure, how it has been incorporated into the assessment process and subsequent management plan, and methodological considerations for further study are detailed.

HIV drug adherence: special situations

Among the highly diverse population of persons living with HIV/AIDS are individuals with particularly challenging life circumstances that can be called "special situations." Substance abuse and homelessness are examples of special situations that require additional consideration when attempting to determine the appropriateness of prescribing complex antiretroviral regimens. When individual cases are examined in the context of relevant models of care and the principles of those models applied, such clinical decisions can be made with the patient. Withholding protease inhibitors from an entire population group, it is argued, is the epitome of practicing bad medicine.

Intrauterine exposure to clomiphene and neonatal persistent hyperplastic primary vitreous

A 4-year-and-10-month-old girl was diagnosed shortly after birth with persistent hyperplastic primary vitreous (PHPV). Her mother took clomiphene 100 mg daily for approximately 4 weeks and discontinued the drug once she had a positive pregnancy test. The exact time of gestation was not clear. Clomiphene is an estrogen antagonist effective in the treatment of anovulation. Various ocular side effects have been described in women taking the drug, including decreased vision, mydriasis, flashing lights, central scotoma, photophobia, diplopia, allergic reactions, retinal vasospasms, detachment posterior vitreous, and possibly posterior subcapsular cataracts. These occur in 1.5-10% of patients taking clomiphene. The potential effects of clomiphene on the fetus have been investigated in five animal studies. Cataracts were observed in fetal mice and rats, but not in monkeys. In humans, a case of congenital retinal aplasia was described. The possibility of clomiphene-induced congenital PHPV should be considered, especially in pregnant women who are taking a high and prolonged dose.

Automated malaria detection by depolarization of laser light

Anecdotal experience with full blood count (FBC) technology incorporating analysis of depolarized laser light (DLL) for the enumeration of eosinophils showed that malaria infection generated unusual distributions in the white cell channels. The objective of this study was to identify and define criteria for a diagnosis of malaria using this technology. To determine sensitivity, specificity, and positive and negative predictive values, 224 directed samples referred specifically for malaria were used; true positives were defined as those in which malaria was identified by microscopic and/or immunological methods. For the DLL method, positive was defined as one or more large mononuclear cell(s) for which the 90 degrees depolarized signal exceeded the 90 degrees polarized signal. To determine possible utility in a routine haematology laboratory setting, 220 random undirected FBC samples were evaluated for possible malaria infection by the DLL method. Of the 224 directed samples, 95 were malaria positive as determined by microscopic and/or immunological methods, and 129 were negative. For the DLL method, overall sensitivity was 72% (90% in the case of Black Africans), and specificity 96%. Positive and negative predictive values overall were 93% and 82% respectively. In the utility study a single positive result was identified among the 220 samples studied. This was found to be from a patient with malaria. The detection of unexpected malaria by automated screening FBC analysis could substantially lower the mortality and morbidity from unascertained infection, especially in indigenous African peoples.

Prevention of graft-versus-host disease (GVHD) by elimination of recipient-reactive donor T cells with recombinant toxins that target the interleukin 2 (IL-2) receptor

Graft-versus-host disease (GVHD), due to the presence of recipient-reactive T cells, limits the usefulness of bone marrow transplantation (BMT) and is a major contributor to patient mortality. To prevent GVHD, murine and human T cells were activated by antigen or mitogens and treated with a genetically engineered form of Pseudomonas exotoxin A (PE) directed against the IL-2 receptor. Treatment with the chimeric toxin eliminated alloreactive cytotoxic T lymphocytes (CTL) as determined by cytotoxicity and mixed lymphocyte culture assays. Precursor frequencies of alloreactive cytotoxic T cells and proliferative T cells were reduced up to 100-fold as shown by limiting dilution assays. Flow cytometric analyses revealed that treatment with the chimeric toxin completely eliminated CD25+ cells from the cultures. Toxin treatment had no significant effect on hematopoietic stem and progenitor cells as determined in vitro by colony-forming assays and in vivo by long-term hematopoietic recovery after 950 rad irradiation. Toxin treatment decreased GVHD in transplanted mice to less than 10% (as compared to 88% in untreated controls). Thus, it is possible to prevent life-threatening GVHD after BMT by using a CD25 receptor-directed toxin to eliminate host-reactive T cells from bone marrow grafts.

B mode ultrasonography--spectrum of paediatric ocular disease

BACKGROUND

Despite having appropriate sonographic equipment available many radiologists remain unfamiliar with B mode sonography of the eye.

OBJECTIVE

This article reviews the advantages and disadvantages of B mode sonography of the paediatric eye. We illustrate the spectrum of eye abnormalities occurring in paediatric practice and the sonographic appearance of clinical entities for which sonography is appropriate.

MATERIALS AND METHOD

We reviewed our experience of eye sonography within a paediatric radiology department over 8 years. A total of 212 sonographic examinations were performed on 206 eyes in 103 children, aged from 3 days to 16 years (mean 4.6 years).

RESULTS

Sonography was well tolerated by the children, was a very useful imaging modality and was the only diagnostic imaging modality required in 94%. Supplementary computed tomography (CT) was performed in ten of 206 eyes (5%) and magnetic resonance imaging (MR) was performed in two of 206 eyes (1%).

CONCLUSIONS

B mode sonography is a very useful imaging modality for suspected ocular or orbital pathology in children and is often the appropriate first line investigation following clinical evaluation. Radiologists familiar with sonography of the eye can provide valuable support to their ophthalmology colleagues.

PROforma: a general technology for clinical decision support systems

The need for flexible and well understood knowledge representations which are capable of capturing clinical guidelines and protocols for decision support systems is widely recognised. The PROforma method for specifying clinical guidelines and protocols comprises a graphical notation for their design, and a formal knowledge representation language to enable them to be executed by a computer to support the management of medical procedures and clinical decision making. PROforma technology consists of a graphical knowledge editor for the creation of guidelines, and an enactment engine for testing and executing them. This paper provides an overview of the motivation and structure of PROforma, and illustrates its use in the development of clinical applications.

Implications for viral uncoating from the structure of bovine enterovirus

We have determined the crystal structure of a bovine enterovirus, revealing that the topologies of the major capsid proteins and the overall architecture of the virion are similar to those of related picornaviruses. The external loops joining beta-strands are truncated and the canyon region is partially filled by an extension of the VP3 G-H loop giving the viral capsid a relatively smooth appearance. These changes may have implications for cell attachment. In spite of these differences the virus maintains a hydrophobic pocket within VP1, occupied by a specific 'pocket factor' which appears to be myristic acid. These observations support the proposal that a kinetic equilibrium exists between occupied and unoccupied pocket states, with occupation inhibiting uncoating.

The role of the general practitioner hospital in inpatient care

The rationale of the general practitioner hospital continues to be questioned. A study of the services and case-mix of two of the four remaining general practitioner hospitals in Northern Ireland was undertaken to determine whether the nature and cost of inpatient care in these hospitals was comparable to the available alternatives. The case-notes of all non-maternity admissions (n = 509) were reviewed. The two hospitals provide acute medical care for a wide range of patients. The majority of patients appeared to require hospitalisation. It is likely that the beds at the two hospitals were mainly a substitute for district general hospital care. The general practitioner hospitals were estimated to be less costly than alternative forms of care, although it was doubtful whether they fulfilled all the structural criteria of quality generally regarded as important for hospitals of this type.

Preliminary crystallographic analysis of bovine enterovirus

Bovine enterovirus (BEV) strain VG-5-27 derived from an infectious cDNA clone has been crystallized as extended hexagonal plates. Virus recovered from crystals produced cytopathic effect in BHK cells. These crystals diffract X-rays from high energy synchrotron sources to beyond 2.7 A. The crystal system is monoclinic, space group P2(1) with unit cell dimensions a = 388 A, b = 390 A, c = 360 A, beta = 113 degrees. The virion is 300 A in diameter and one whole particle constitutes the crystallographic asymmetric unit, giving rise to 60-fold non-crystallographic redundancy.

The Flexipore 6000 membrane as a wound dressing for use in the accident and emergency department

Images

Characteristics of a cetacean morbillivirus isolated from a porpoise (Phocoena phocoena)

A virus isolated from a porpoise during the 1988 seal epizootic was shown to be a morbillivirus. In order to determine the relationship of the virus to phocine distemper virus (PDV) a battery of monoclonal antibodies raised against canine distemper virus (CDV), PDV or the porpoise isolate were assessed for their ability to bind to CDV, PDV or porpoise virus epitopes in indirect immunofluorescence assays and ELISAs. The porpoise isolate contained several unique epitopes and several epitopes present on CDV and PDV were absent on the porpoise isolate. The data presented in this study indicate that the porpoise virus is an antigenically distinct morbillivirus and as such has been tentatively named as delphinoid distemper virus (DDV).

Osteoclast recruitment in response to human bone matrix is age related

The effect of bone matrix age on the recruitment and differentiation of osteoclast precursors was studied using the chick chorioallantoic membrane (CAM) implant system. Devitalized mineralized bone particles (75-250 microns) were prepared from human femoral cortical bone obtained postmortem from 8 men (age range: 18-72 years). The particles were implanted onto the CAM and 8 days later implants were harvested and processed for light microscopic, morphometric or immunohistochemical analysis. Histomorphometric analysis was performed on samples representing each donor age. The analysis was grouped into three categories consisting of bone from young adults (18-20 years), adults (34-53 years) and aged individuals (67 years and older). Total osteoclast number, osteoclast number per bone particle, cell area, cell size, number of nuclei per cell profile, nucleocytoplasmic ratio, and the presence of a distinctive osteoclast antigen defined by monoclonal anti-body 121F were determined. Bone matrix from older individuals, and therefore the oldest age group (67 years and older), elicited significantly fewer multinucleated cells when compared to bone matrix from younger donors. The number of nuclei per cell profile was highest in the adult population (34-53 years), and there was a continuous increase in cell area with aging. As a consequence, the nucleocytoplasmic ratio decreased from the youngest to the oldest age group. These findings indicate that, relative to factors that affect the recruitment and differentiation of osteoclast precursor cells, bone matrix of older individuals is changed in quality and/or quantity compared to bone matrix from younger individuals. It is hypothesized that this decline in osteoclast formation in response to older bone matrix may contribute to the impaired bone remodeling associated with aging.