Feasibility of regional center telehealth visits utilizing a rural research network in people with Parkinson's disease

Background

Impaired motor and cognitive function can make travel cumbersome for People with Parkinson's disease (PwPD). Over 50% of PwPD cared for at the University of Arkansas for Medical Sciences (UAMS) Movement Disorders Clinic reside over 30 miles from Little Rock. Improving access to clinical care for PwPD is needed.

Objective

To explore the feasibility of remote clinic-to-clinic telehealth research visits for evaluation of multi-modal function in PwPD.

Methods

PwPD residing within 30 miles of a UAMS Regional health center were enrolled and clinic-to-clinic telehealth visits were performed. Motor and non-motor disease assessments were administered and quantified. Results were compared to participants who performed at-home telehealth visits using the same protocols during the height of the COVID pandemic.

Results

Compared to the at-home telehealth visit group (n = 50), the participants from regional centers (n = 13) had similar age and disease duration, but greater disease severity with higher total Unified Parkinson's disease rating scale scores (Z = -2.218, p = 0.027) and lower Montreal Cognitive Assessment scores (Z = -3.350, p < 0.001). Regional center participants had lower incomes (Pearson's chi = 21.3, p < 0.001), higher costs to attend visits (Pearson's chi = 16.1, p = 0.003), and lived in more socioeconomically disadvantaged neighborhoods (Z = -3.120, p = 0.002). Prior research participation was lower in the regional center group (Pearson's chi = 4.5, p = 0.034) but both groups indicated interest in future research participation.

Conclusions

Regional center research visits in PwPD in medically underserved areas are feasible and could help improve access to care and research participation in these traditionally underrepresented populations.

Chest imaging representing a COVID-19 positive rural U.S. population

As the COVID-19 pandemic unfolds, radiology imaging is playing an increasingly vital role in determining therapeutic options, patient management, and research directions. Publicly available data are essential to drive new research into disease etiology, early detection, and response to therapy. In response to the COVID-19 crisis, the National Cancer Institute (NCI) has extended the Cancer Imaging Archive (TCIA) to include COVID-19 related images. Rural populations are one population at risk for underrepresentation in such public repositories. We have published in TCIA a collection of radiographic and CT imaging studies for patients who tested positive for COVID-19 in the state of Arkansas. A set of clinical data describes each patient including demographics, comorbidities, selected lab data and key radiology findings. These data are cross-linked to SARS-COV-2 cDNA sequence data extracted from clinical isolates from the same population, uploaded to the GenBank repository. We believe this collection will help to address population imbalance in COVID-19 data by providing samples from this normally underrepresented population.

Measurement(s)	COVID-19 image features • chest • viral genome
Technology Type(s)	Radiograph • computed tomography • whole genome sequencing
Factor Type(s)	COVID-19 diagnosis
Sample Characteristic - Organism	Homo sapiens • SARS-CoV-2
Sample Characteristic - Environment	rural area
Sample Characteristic - Location	United States of America

Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.12980795

Chest imaging representing a COVID-19 positive rural U.S. population

As the COVID-19 pandemic unfolds, radiology imaging is playing an increasingly vital role in determining therapeutic options, patient management, and research directions. Publicly available data are essential to drive new research into disease etiology, early detection, and response to therapy. In response to the COVID-19 crisis, the National Cancer Institute (NCI) has extended the Cancer Imaging Archive (TCIA) to include COVID-19 related images. Rural populations are one population at risk for underrepresentation in such public repositories. We have published in TCIA a collection of radiographic and CT imaging studies for patients who tested positive for COVID-19 in the state of Arkansas. A set of clinical data describes each patient including demographics, comorbidities, selected lab data and key radiology findings. These data are cross-linked to SARS-COV-2 cDNA sequence data extracted from clinical isolates from the same population, uploaded to the GenBank repository. We believe this collection will help to address population imbalance in COVID-19 data by providing samples from this normally underrepresented population.

Frequency of surgery and hospital admissions for communicable diseases in a high- and middle-income setting

BACKGROUND

In high-income countries, non-communicable diseases drive the demand for surgical healthcare. Middle-income countries face a double disease burden, of both communicable and non-communicable disease. The aim of this study was to describe the role of surgery for the in-hospital care of infectious conditions in the high-income country Sweden and the middle-income country South Africa.

METHODS

A retrospective cohort study was performed of 1.4 million infectious disease admissions. The study populations were the entire population of Sweden, and a cohort of 3.5 million South Africans with private healthcare insurance, during a 7-year interval. The outcome measures were frequency of surgical procedures across a spectrum of diseases, and sex and age during the medical care event.

RESULTS

Some 8.1 per cent of Swedish and 15.7 per cent of South African hospital admissions were because of infectious disease. The proportion of infectious disease admissions that were associated with surgery was constant over time: 8.0 (95 per cent c.i. 7.9 to 8.1) per cent in Sweden and 21.1 (21.0 to 21.2) per cent in South Africa. The frequency of surgery was 2.6 (2.6 to 2.7) times greater in South Africa, and 2.2 (2.2 to 2.3) times higher after standardization for age, sex and disease category.

CONCLUSION

The study suggests that surgical care is required to manage patients with communicable diseases, even in high-income settings with efficient prevention and functional primary care. These results further stress the importance of scaling up functional surgical health systems in low- and middle-income countries, where the disease burden is distinguished by infectious disease.

Exemestane for primary prevention of breast cancer in postmenopausal women: NCIC CTG MAP.3—A randomized, placebo-controlled clinical trial

LBA504

Background: Limited efficacy and serious toxicities have limited uptake of tamoxifen or raloxifene as preventatives of breast cancer. Aromatase inhibitors (AIs) prevent contralateral breast cancers more than tamoxifen in adjuvant trials and have fewer serious side effects. This is the first report of an AI used in primary prevention. Methods: NCIC CTG MAP.3 is a randomized trial designed to detect a 65% reduction in annual incidence of invasive breast cancer (IBC) on exemestane (E) versus placebo (P). Eligible postmenopausal women had ≥ one of the following risk factors: Gail score >1.66%, prior ADH, ALH, LCIS or DCIS with mastectomy, age over 60. Health-related and menopause-specific quality of life (QOL) were assessed by SF-36 and MENQOL questionnaires. Results: From 2004-2010, 4,560 women were randomized: age 62.5 yrs (37-90); Gail Score 2.3 % (0.6-21); BMI 28.0 kg/m2 (15.9-65.4). Risk factors included: age >60 yrs (49%); Gail score >1.66 (40%); and prior ADH, ALH, LCIS or DCIS with mastectomy (11%). At median follow-up of 35 months there were 11 IBCs on E and 32 on P (annual incidence 0.19% vs 0.55%; HR= 0.35, 95% CI 0.18-0.70, p = 0.002); ductal (10E/27P), lobular (1E/5P). Most tumors were ER positive (7E/27P); Her2/neu negative (10E/26P); TNM stage T1 (8E/28P), N0 (7E/22P), M0 (11E/30P). E was superior in all subgroups: by Gail score, age, BMI, prior LCIS and DCIS. The annual incidence rate of IBC or DCIS was 0.35% E and 0.77% P (HR=0.47;95% CI 0.27-0.79; p = 0.004) based on 64 IBCs or DCISs (20E/44P). Clinical bone fractures, osteoporosis, hypercholesterolemia or cardiovascular events were equal in both arms. No clinically meaningful differences in QOL were detected. Conclusions: Exemestane significantly reduced invasive and pre-invasive breast cancers in postmenopausal women at increased risk for breast cancer with no serious toxicities. Exemestane should be considered a new option for primary prevention of breast cancer. Supported by the Canadian Cancer Society; Pfizer Inc. PEG supported in part by Avon Foundation.

Effect of vitamin levels on biomarkers of exposure and oxidative damage-the EXPAH study

DNA adducts are markers of carcinogen exposure and of their biological effect; they have been shown to be related to mutagenesis, and therefore they could be a predictive biomarker of human cancer. The objective of this study was to assess if there is a relationship between vitamins A, C, and E, which are known to play a significant role as free radical scavengers and antioxidant agents, and biomarkers of genotoxicity and oxidative stress. Three hundred and fifty-six subjects from Czech Republic, Slovak Republic and Bulgaria, who completed a questionnaire on dietary information and had a measurement of plasma A, C, E vitamins, DNA adduct levels (benzo[a]pyrene (B[a]P) and bulky (DNA-Tot) DNA adducts) and oxidative damage (cyclic pyrimidopurinone N-1,N2 malondialdehyde-2 deoxyguanosine (M1dG) and 8-oxo-7,8-dihydro-2_deoxyguanosine (8-oxodG)) were analyzed. A significant inverse correlation was observed between plasma vitamin levels and both benzo[a]pyrene (B[a]P) and bulky DNA adducts. Vitamin A was also significantly inversely correlated with M1dG, a marker of oxidative damage. The associations were stronger in non-smokers than in smokers. Dietary intake of certain antioxidants such as vitamins is associated with reduced levels of markers of DNA damage (B[a]P and DNA-Tot) and oxidation (M1dG and 8-oxodG) measured in peripheral white blood cells. This could contribute to the protective role of such a dietary pattern on cancer risk. The protective effect of dietary vitamins is less evident in smokers.

Limitations in knowledge of HIV transmission among HIV-positive patients accessing case management services in a resource-poor setting

HIV has increasingly become an infection of poverty. Adequate HIV transmission knowledge among HIV-positive patients is necessary to reduce the risk of secondary infection and protect those who are uninfected from transmission. This study was conducted among individuals enrolled in a program that serves impoverished HIV patients in the Boston area. Although the mean HIV transmission knowledge score was 80% for this group, a significant proportion of patients demonstrated limitations in knowledge of HIV transmission. Highly vulnerable patients, such as those who reported not accessing HIV medications, a history of sexual abuse, or problems getting clothing, had lower levels of HIV knowledge. This paper hopes to alert providers that their most vulnerable patients may be at an increased risk of re-infection or transmission due to limited HIV knowledge. Programs that serve HIV-positive patients coping with poverty and other serious problems need to ensure adequate knowledge of HIV transmission to reduce the overall burden of HIV in resource-poor settings.

Identification of chlamydia and gonorrhoea among women in rural Haiti: maximising access to treatment in a resource poor setting

OBJECTIVE

To develop a risk assessment algorithm that will increase the identification and treatment of women with cervical infection in rural Haiti.

METHODS

Study participants were randomly selected from new patients who accessed services at a women's health clinic in rural Haiti between June 1999 and December 2002. This case-control study included women who tested positive for chlamydia and/or gonorrhoea based on the Gen-Probe PACE 2 laboratory test as cases. Controls were women who tested negative for both of these infections.

RESULTS

Women from this area of rural Haiti had a limited level of education and lived in impoverished housing conditions. The sensitivity estimates of Haitian Ministry of Health and WHO algorithms for detecting chlamydia and/or gonorrhoea were generally low (ranging from 16.1% to 68.1%) in this population. Risk scores based on logistic regression models of local risk factors for chlamydia and gonorrhoea were developed and sensitivity estimates were higher for algorithms based on these risk scores (up to 98.8%); however, specificity was compromised.

CONCLUSIONS

A risk assessment algorithm to identify women with chlamydia and/or gonorrhoea is more sensitive and less specific than the syndromic management approach advocated by WHO and adapted by the Haitian Ministry of Health. Using a risk assessment tool with high sensitivity based on local risk factors of cervical infection will maximise access to care, improve outcomes, and decrease morbidity in women who have cervical infection in rural Haiti.

A high-density genetic map of hexaploid wheat (Triticum aestivum L.) from the cross Chinese Spring x SQ1 and its use to compare QTLs for grain yield across a range of environments

A population of 96 doubled haploid lines (DHLs) was prepared from F1 plants of the hexaploid wheat cross Chinese Spring x SQ1 (a high abscisic acid-expressing breeding line) and was mapped with 567 RFLP, AFLP, SSR, morphological and biochemical markers covering all 21 chromosomes, with a total map length of 3,522 cM. Although the map lengths for each genome were very similar, the D genome had only half the markers of the other two genomes. The map was used to identify quantitative trait loci (QTLs) for yield and yield components from a combination of 24 site x treatment x year combinations, including nutrient stress, drought stress and salt stress treatments. Although yield QTLs were widely distributed around the genome, 17 clusters of yield QTLs from five or more trials were identified: two on group 1 chromosomes, one each on group 2 and group 3, five on group 4, four on group 5, one on group 6 and three on group 7. The strongest yield QTL effects were on chromosomes 7AL and 7BL, due mainly to variation in grain numbers per ear. Three of the yield QTL clusters were largely site-specific, while four clusters were largely associated with one or other of the stress treatments. Three of the yield QTL clusters were coincident with the dwarfing gene Rht-B1 on 4BS and with the vernalisation genes Vrn-A1 on 5AL and Vrn-D1 on 5DL. Yields of each DHL were calculated for trial mean yields of 6 g plant(-1) and 2 g plant(-1) (equivalent to about 8 t ha(-1) and 2.5 t ha(-1), respectively), representing optimum and moderately stressed conditions. Analyses of these yield estimates using interval mapping confirmed the group-7 effects on yield and, at 2 g plant(-1), identified two additional major yield QTLs on chromosomes 1D and 5A. Many of the yield QTL clusters corresponded with QTLs already reported in wheat and, on the basis of comparative genetics, also in rice. The implications of these results for improving wheat yield stability are discussed.

[European multicenter cross-sectional study on exposure to low doses of benzene]

A cross-sectional multicenter european study has been carried out to evacuate the relations between exposure to low level of benzene and biological markers of internal dose (t,t-MA, S-PMA) and early biological effect (DNA-SSB). The research has shown significantly increased levels (adjusted for smoking habits) of the urinary excretion of t,t-MA, S-PMA and DNA-SSB in petrochemical workers (mean benzene level = 5,694 micrograms/m3) but not in filling station attendants, traffic police officers, and bus drivers compared to referent workers. Dose-response relations were detected between benzene air levels, t,t-MA, S-PMA and DNA-SSB in petrochemical workers, with significantly increased levels of DNA-SSB detected for benzene exposure levels in the range 391-1,800 micrograms/m3 (0.12-0.58 ppm).

Clinical and programmatic considerations in the treatment of MDR-TB in children: a series of 16 patients from Lima, Peru

SETTING

Since 2000, the directly observed treatment, short-course (DOTS) strategy has been expanded in several countries to include treatment of multidrug-resistant tuberculosis (MDR-TB). This strategy is known as DOTS-Plus. Tuberculosis is a common cause of morbidity and mortality for children throughout the developing world. Children may also be infected with MDR-TB, yet most developing countries do not specifically address pediatric MDR-TB.

OBJECTIVE

To present the intermediate outcomes of the first 16 children enrolled in the Peruvian DOTS-Plus program and to demonstrate the tolerability of second-line anti-tuberculosis drugs.

RESULTS

Three children completed therapy and are cured, one child had bacteriologic and clinical failure after 12 months of therapy and died of respiratory insufficiency, and 12 have intermediate outcomes demonstrating favorable clinical, bacteriologic, and radiographic evidence of improvement after 9-19 months of therapy.

CONCLUSIONS

Of the 16 pediatric DOTS-Plus patients, 15 have tolerated therapy well and have had favorable clinical evolution. However, the diagnosis of pediatric MDR-TB is often extremely delayed due to reliance on the adult case definition and should be changed to prevent progressive, chronic illness in such children. Programmatic changes could facilitate earlier diagnosis and treatment of pediatric MDR-TB in Peru and in other DOTS-Plus programs.

Reducing psychiatric stigma and discrimination--evaluating an educational intervention with the police force in England

BACKGROUND

Across the world there are programmes challenging negative stereotypes of people with mental health problems and associated discriminatory behaviours, but the evidence base describing what works in practice is still underdeveloped. This paper evaluates the effectiveness of a mental health training intervention with the police force in England.

METHOD

A total of 109 police officers attended training workshops and completed pre- and post-questionnaires detailing knowledge, attitudes and behavioural interventions.

RESULTS

Mean attitude scores fell from 2.4 at baseline to 2.3 at follow-up (p < 0.0001) using a 5-point Likert scale. Five key message statements were assessed - 70 % of cases successfully reported more messages at follow-up as compared to baseline; however, the stereotype linking people with mental health problems with violent behaviour overall was not successfully challenged. Positive impacts on police work, particularly improvements in communication between officers and subjects, were reported by a third of cases.

CONCLUSIONS

Short educational interventions can produce changes in participants' reported attitudes towards people with mental health problems, and can leave police officers feeling more informed and more confident to support people in mental distress.

BIOMarkers for occupational diesel exhaust exposure monitoring (BIOMODEM)--a study in underground mining

Methods for the assessment of exposures to diesel exhaust were evaluated, including various biomarkers of internal exposure and early biological effects. The impact of possible biomarkers of susceptibility was also explored. Underground workers (drivers of diesel-powered excavators) at an oil shale mine in Estonia were compared with surface workers. Personal exposures to particle-associated 1-nitropyrene (NP) were some eight times higher underground than on the surface. Underground miners were also occupationally exposed to benzene and polycyclic aromatic hydrocarbons, as indicated by excretion of urinary metabolites of benzene and pyrene. In addition, increased O(6)-alkylguanine DNA adducts were detected in the white blood cells of underground workers, suggesting higher exposure to nitroso-compounds. However, no differences between underground and surface workers were observed in the levels of other bulky DNA adducts determined by 32P-postlabelling, or in DNA damage. The study indicated that smoking, diet and residential indoor air pollution are important non-occupational factors to consider when interpreting biomonitoring results.

DOTS and DOTS-plus: not the only answer

Multidrug-resistant tuberculosis is already a global pandemic, with focal "hot spots" of ongoing transmission. Although DOTS (directly observed treatment, short course) chemotherapy is the goal of global tuberculosis control, short-course chemotherapy will not cure multidrug-resistant tuberculosis. In settings of high transmission of multidrug-resistant tuberculosis, "DOTS plus" (a complementary DOTS-based strategy with provisions for treating multidrug-resistant tuberculosis) is warranted. DOTS-plus project implementation to date reveals important clinical, epidemiological, and economic lessons. Community-based strategies designed to enhance local capacity are cost effective and make it possible to meet new medical challenges.

Scrape cytology of meningioangiomatosis: a report of two cases with diagnostic cytologic features

BACKGROUND

Meningioangiomatosis is a rare, probably hamartomatous condition characterized by nonneoplastic intracortical proliferation of meningothelial cells, capillaries and fibroblasts. The lesion may mimic a tumor both clinically and radiologically. We present two cases of the entity, including its cytologic features.

CASES

A 71-year-old man presented with an eight-month history of headache, change in vision, loss of depth perception and unsteady gait. Magnetic resonance imaging (MRI) revealed an infiltrative lesion of the left occipital lobe, diffuse in nature. Cytologic smears prepared at the time of intraoperative consultation showed numerous thin-walled capillaries together with bland spindle cells. Occasional large cells with prominent nucleoli were also present. Frozen section confirmed the presence of linear, small capillaries surrounded by fibroblasts and meningothelial cells, consistent with meningioangiomatosis. The second case was a 3-year-old girl who presented with a one-day history of seizure, vomiting, fever and perioral cyanosis. MRI revealed an enhancing lesion in a temporal lobe of the cerebrum. The patient underwent excision of the lesion. Intraoperative cytology showed numerous meningothelial whorls together with neurons and occasional capillaries. Both patients were well, one after three months and the other after six.

CONCLUSION

Meningioangiomatosis is a lesion characterized by linear capillaries, meningothelial cells and neurons, some exhibiting nuclear atypia. The combination can lead to an erroneous diagnosis of more common conditions, such as meningioma (with intracortical extension) and anaplastic astrocytoma. Contrary to these more sinister diagnoses, meningioangiomatosis is a completely benign, presumably hamartomatous entity.

Case report: primary isolated angiomyolipoma of the spleen

A primary isolated angiomyolipoma presenting as a splenic mass is described. This is the first reported case of primary splenic angiomyolipoma without angiomyolipoma in the kidney or evidence of tuberous sclerosis, and it coexists with an adenocarcinoid of the appendix.

Biomarkers of genotoxicity of urban air pollution. Overview and descriptive data from a molecular epidemiology study on populations exposed to moderate-to-low levels of polycyclic aromatic hydrocarbons: the AULIS project

Epidemiologic studies indicate that prolonged exposure to high pollution levels is associated with increased risk of cancer, especially lung cancer. However, under conditions of moderate or low air pollution, epidemiologic evidence does not permit reliable conclusions. Biomarker-based population studies may serve as complementary tools providing a better understanding of the relative contribution of ambient atmospheric pollution to the overall genotoxic burden suffered by city dwellers. However, past efforts to apply biomarkers to studies of low levels exposure to urban air pollution have given inconclusive results, partly because of the absence of adequate data on personal exposure, covering a time-window which is appropriate for the biomarkers being examined, as well as a battery of biomarkers reflecting different stages of the carcinogenic process. In the present paper, the potential of biomarker-based population studies to aid the assessment of the genotoxic and carcinogenic effects of urban air pollution is reviewed by reference to the achievements and limitations of earlier reported studies. The design and methodology adopted in a recently completed large-scale population study, carried out in the context of the European Union Environment and Climate Programme, known by the short name of AULIS project, is discussed and descriptive statistics of the main findings of the project are presented. These findings indicate that for cohorts suffering moderate-to-low exposures to airborne particulate-bound polycyclic aromatic hydrocarbons (PAHs), no simple correlation with biomarkers of genotoxicity existed and suggest that additional factors made a significant contribution to the overall genotoxic burden.

Papillary fibroelastoma of the heart: report of two cases and review of the literature

Papillary fibroelastoma is the most common primary cardiac valvular tumor. Historically, papillary fibroelastoma was an incidental autopsy finding, deemed to have no clinical significance. More recently, reports of symptomatic cases of papillary fibroelastoma with complications such as myocardial infarction and stroke have led papillary fibroelastoma to be considered a potentially dangerous lesion. We report 2 cases of symptomatic papillary fibroelastoma, both of which presented with a stroke. Both patients underwent uneventful open-heart surgery. The literature is reviewed, with a compilation of 79 cases.

Redox regulation in human melanocytes and melanoma

The human melanocyte is continuously exposed to intrinsic and extrinsic sources of reactive biochemical species, but is finely tuned via the intrinsic anti-oxidant and radical properties of melanin to suppress the build-up of an altered redox phenotype. We propose that this control is lost during melanomagenesis and inappropriate redox-sensitive transcriptional factor activations occur which result in enhancement of an anti-apoptotic phenotype in the transformed cell. This conceptual framework offers testable steps to determine the role of redox alterations in the carcinogenic evolution, prevention and treatment of melanoma and other diseases of the melanocyte.

Historical declines in tuberculosis: nature, nurture and the biosocial model

The large declines in the incidence of tuberculosis over time in the industrially developed nations have usually been attributed to natural selection or to socio-economic improvements. Both explanations are beset with problems, as there is little firm evidence for the occurrence of natural selection of resistance to tuberculosis to any significant extent, and doubts have been expressed as to whether the incidence of a disease can be directly related to measures of socio-economic change without consideration of the impact of the many specific public health measures that have been taken. In addition, analyses of the changing prevalence of tuberculosis must consider the impact of changing environmental and ecological factors that affect, for example, the immunising effect of exposure to Mycobacterium bovis and saprophytic mycobacteria. It is also necessary to determine whether the causative organism is undergoing evolutionary change, as recent reports suggest.

Community-based treatment of advanced HIV disease: introducing DOT-HAART (directly observed therapy with highly active antiretroviral therapy)

In 2000, acquired immunodeficiency syndrome (AIDS) overtook tuberculosis (TB) as the world's leading infectious cause of adult deaths. In affluent countries, however, AIDS mortality has dropped sharply, largely because of the use of highly active antiretroviral therapy (HAART). Antiretroviral agents are not yet considered essential medications by international public health experts and are not widely used in the poor countries where human immunodeficiency virus (HIV) takes its greatest toll. Arguments against the use of HAART have mainly been based on the high cost of medications and the lack of the infrastructure necessary for using them wisely. We re- examine these arguments in the setting of rising AIDS mortality in developing countries and falling drug prices, and describe a small community-based treatment programme based on lessons gained in TB control. With the collaboration of Haitian community health workers experienced in the delivery of home-based and directly observed treatment for TB, an AIDS-prevention project was expanded to deliver HAART to a subset of HIV patients deemed most likely to benefit. The inclusion criteria and preliminary results are presented. We conclude that directly observed therapy (DOT) with HAART, "DOT-HAART", can be delivered effectively in poor settings if there is an uninterrupted supply of high-quality drugs.

Inhibition of osteoblast differentiation by tumor necrosis factor-alpha

Tumor necrosis factor-alpha (TNF-alpha) has a key role in skeletal disease in which it promotes reduced bone formation by mature osteoblasts and increased osteoclastic resorption. Here we show that TNF inhibits differentiation of osteoblasts from precursor cells. TNF-alpha treatment of fetal calvaria precursor cells, which spontaneously differentiate to the osteoblast phenotype over 21 days, inhibited differentiation as shown by reduced formation of multilayered, mineralizing nodules and decreased secretion of the skeletal-specific matrix protein osteocalcin. The effect of TNF was dose dependent with an IC50 of 0.6 ng/ml, indicating a high sensitivity of these precursor cells. Addition of TNF-alpha from days 2-21, 2-14, 7-14, and 7-10 inhibited nodule formation but addition of TNF after day 14 had no effect. Partial inhibition of differentiation was observed with addition of TNF on only days 7-8, suggesting that TNF could act during a critical period of phenotype selection. Growth of cells on collagen-coated plates did not prevent TNF inhibition of differentiation, suggesting that inhibition of collagen deposition into matrix by proliferating cells could not, alone, explain the effect of TNF. Northern analysis revealed that TNF inhibited the expression of insulin-like growth factor I (IGF-I). TNF had no effect on expression of the osteogenic bone morphogenic proteins (BMPs-2, -4, and -6), or skeletal LIM protein (LMP-1), as determined by semiquantitative RT-PCR. Addition of IGF-I or BMP-6 to fetal calvaria precursor cell cultures enhanced differentiation but could not overcome TNF inhibition, suggesting that TNF acted downstream of these proteins in the differentiation pathway. The clonal osteoblastic cell line, MC3T3-E1-14, which acquires the osteoblast phenotype spontaneously in postconfluent culture, was also studied. TNF inhibited differentiation of MC3T3-E1-14 cells as shown by failure of mineralized matrix formation in the presence of calcium and phosphate. TNF was not cytotoxic to either cell type as shown by continued attachment and metabolism in culture, trypan blue exclusion, and Alamar Blue cytotoxicity assay. These results demonstrate that TNF-alpha is a potent inhibitor of osteoblast differentiation and suggest that TNF acts distal to IGF-I, BMPs, and LMP-1 in the progression toward the osteoblast phenotype.