Stress fracture of the ulna associated with bisphosphonate therapy and use of walking aid.

We report a case of a stress fracture of the ulna secondary to long-term bisphosphonate therapy and walking cane. Physicians need to have a high index of suspicion of stress fractures occurring in patients complaining of chronic upper limb pain if they are on bisphosphonate therapy and are using walking aids. Stress fractures of the upper extremities are rare and are usually associated with athletes; however, a few recent case reports have shown an association between stress fractures of the upper extremities and the use of walking aids. The association between increased incidence of upper extremity stress fractures and the use of both bisphosphonates and walking aids in patients has not been well studied, with only one previously reported case. Here, we report a case of a complete stress fracture of the ulna in a 77-year-old female, premorbidly ambulant with walking cane, on long-term bisphosphonates without any pre-existing medical conditions which could result in secondary causes of bone loss. Investigations did not reveal any causes of pathological fracture. This fracture is attributed to the use of long-term bisphosphonate therapy in conjunction with the use of a walking cane. This case highlights the importance of entertaining the possibility of such fractures occurring in any patient who is on bisphosphonate therapy presenting with stress fractures of the upper extremity.

Shaped by Their Environment: Variation in Blue Whale Morphology across Three Productive Coastal Ecosystems.

Species ecology and life history patterns are often reflected in animal morphology. Blue whales are globally distributed, with distinct populations that feed in different productive coastal regions worldwide. Thus, they provide an opportunity to investigate how regional ecosystem characteristics may drive morphological differences within a species. Here, we compare physical and biological oceanography of three different blue whale foraging grounds: (1) Monterey Bay, California, USA; (2) the South Taranaki Bight (STB), Aotearoa New Zealand; and (3) the Corcovado Gulf, Chile. Additionally, we compare the morphology of blue whales from these regions using unoccupied aircraft imagery. Monterey Bay and the Corcovado Gulf are seasonally productive and support the migratory life history strategy of the Eastern North Pacific (ENP) and Chilean blue whale populations, respectively. In contrast, the New Zealand blue whale population remains in the less productive STB year-round. All three populations were indistinguishable in total body length. However, New Zealand blue whales were in significantly higher body condition despite lower regional productivity, potentially attributable to their non-migratory strategy that facilitates lower risk of spatiotemporal misalignment with more consistently available foraging opportunities. Alternatively, the migratory strategy of the ENP and Chilean populations may be successful when their presence on the foraging grounds temporally aligns with abundant prey availability. We document differences in skull and fluke morphology between populations, which may relate to different feeding behaviors adapted to region-specific prey and habitat characteristics. These morphological features may represent a trade-off between maneuverability for prey capture and efficient long-distance migration. As oceanographic patterns shift relative to long-term means under climate change, these blue whale populations may show different vulnerabilities due to differences in migratory phenology and feeding behavior between regions. Spanish abstract La ecología y patrones de historia de vida de las especies a menudo se reflejan en la morfología animal. Las ballenas azules están distribuidas globalmente, con poblaciones separadas que se alimentan en diferentes regiones costeras productivas de todo el mundo. Por lo tanto, brindan la oportunidad de investigar cómo las características regionales de los ecosistemas pueden impulsar diferencias morfológicas dentro de una especie. Aquí, comparamos la oceanografía física y biológica de tres zonas de alimentación diferentes de la ballena azul: (1) Bahía de Monterey, California, EE. UU., (2) Bahía del sur de Taranaki (BST), Nueva Zelanda, y (3) Golfo de Corcovado, Chile. Adicionalmente, comparamos la morfología de las ballenas azules de estas regiones utilizando imágenes de aeronaves no tripuladas. La Bahía de Monterey y el Golfo de Corcovado son estacionalmente productivos y apoyan la estrategia migratoria de la historia de vida de las poblaciones de ballena azul chilena y del Pacífico Norte Oriental (PNO), respectivamente. Por el contrario, la población de ballena azul de Nueva Zelanda permanece en la menos productiva BST durante todo el año. Las tres poblaciones eran indistinguibles en cuanto a la longitud corporal total. Sin embargo, las ballenas azules de Nueva Zelanda tenían una condición corporal significativamente mayor a pesar de una menor productividad regional, potencialmente atribuible a su estrategia no migratoria que facilita un menor riesgo de desalineación espaciotemporal con oportunidades de alimentación disponibles de manera más consistente. Alternativamente, la estrategia migratoria de las poblaciones de ballenas PNO y chilena puede tener éxito cuando su presencia en las zonas de alimentación se alinea temporalmente con la abundante disponibilidad de presas. Documentamos diferencias en la morfología del cráneo y la aleta caudal entre poblaciones, que pueden estar relacionadas con diferentes comportamientos de alimentación adaptados a las características de hábitat y presas específicas para cada región. Estas características morfológicas pueden representar una compensación entre la maniobrabilidad para la captura de presas y una migración eficiente a larga distancia. A medida que los patrones oceanográficos cambian en términos de mediano a largo plazo debido al cambio climático, estas poblaciones de ballenas azules pueden mostrar diferentes vulnerabilidades debido a diferencias en la fenología migratoria y el comportamiento de alimentación entre regiones.

Choroid Plexus Calcification Correlates with Cortical Microglial Activation in Humans: A Multimodal PET, CT, MRI Study.

BACKGROUND AND PURPOSE: The choroid plexus (CP) within the brain ventricles is well-known to produce cerebrospinal fluid (CSF). Recently, the CP has been recognized as critical in modulating inflammation. MRI-measured CP enlargement has been reported in neuroinflammatory disorders like MS as well as with aging and neurodegeneration. The basis of MRI-measured CP enlargement is unknown. On the basis of tissue studies demonstrating CP calcification as a common pathology associated with aging and disease, we hypothesized that previously unmeasured CP calcification contributes to MRI-measured CP volume and may be more specifically associated with neuroinflammation. MATERIALS AND METHODS: We analyzed 60 subjects (43 healthy controls and 17 subjects with Parkinson's disease) who underwent PET/CT using 11C-PK11195, a radiotracer sensitive to the translocator protein expressed by activated microglia. Cortical inflammation was quantified as nondisplaceable binding potential. Choroid plexus calcium was measured via manual tracing on low-dose CT acquired with PET and automatically using a new CT/MRI method. Linear regression assessed the contribution of choroid plexus calcium, age, diagnosis, sex, overall volume of the choroid plexus, and ventricle volume to cortical inflammation. RESULTS: Fully automated choroid plexus calcium quantification was accurate (intraclass correlation coefficient with manual tracing = .98). Subject age and choroid plexus calcium were the only significant predictors of neuroinflammation. CONCLUSIONS: Choroid plexus calcification can be accurately and automatically quantified using low-dose CT and MRI. Choroid plexus calcification-but not choroid plexus volume-predicted cortical inflammation. Previously unmeasured choroid plexus calcium may explain recent reports of choroid plexus enlargement in human inflammatory and other diseases. Choroid plexus calcification may be a specific and relatively easily acquired biomarker for neuroinflammation and choroid plexus pathology in humans.

Multimodality Imaging in Primary Progressive Aphasia.

Primary progressive aphasia is a clinically and neuropathologically heterogeneous group of progressive neurodegenerative disorders, characterized by language-predominant impairment and commonly associated with atrophy of the dominant language hemisphere. While this clinical entity has been recognized dating back to the 19th century, important advances have been made in defining our current understanding of primary progressive aphasia, with 3 recognized subtypes to date: logopenic variant, semantic variant, and nonfluent/agrammatic variant. Given the ongoing progress in our understanding of the neurobiology and genomics of these rare neurodegenerative conditions, accurate imaging diagnoses are of the utmost importance and carry implications for future therapeutic triaging. This review covers the diverse spectrum of primary progressive aphasia and its multimodal imaging features, including structural, functional, and molecular neuroimaging findings; it also highlights currently recognized diagnostic criteria, clinical presentations, histopathologic biomarkers, and treatment options of these 3 primary progressive aphasia subtypes.

The importance of leukotrienes in airway inflammation in a mouse model of asthma.

Inhalation of antigen in immunized mice induces an infiltration of eosinophils into the airways and increased bronchial hyperreactivity as are observed in human asthma. We employed a model of late-phase allergic pulmonary inflammation in mice to address the role of leukotrienes (LT) in mediating airway eosinophilia and hyperreactivity to methacholine. Allergen intranasal challenge in OVA-sensitized mice induced LTB4 and LTC4 release into the airspace, widespread mucus occlusion of the airways, leukocytic infiltration of the airway tissue and broncho-alveolar lavage fluid that was predominantly eosinophils, and bronchial hyperreactivity to methacholine. Specific inhibitors of 5-lipoxygenase and 5-lipoxygenase-activating protein (FLAP) blocked airway mucus release and infiltration by eosinophils indicating a key role for leukotrienes in these features of allergic pulmonary inflammation. The role of leukotrienes or eosinophils in mediating airway hyperresponsiveness to aeroallergen could not be established, however, in this murine model.

The changing pattern of primary glomerulonephritis in Singapore and other countries over the past 3 decades.

This review of 2,586 renal biopsies over the past 3 decades in Singapore documents the changing pattern of glomerulonephritis (GN) from that of a third world country to that of a developed nation. In the 1st decade, mesangial proliferative glomerulonephritis was the most common form of primary GN, just as it was in the surrounding Asian countries. In the 2nd decade, the prevalence of mesangial proliferative GN decreased with a rise in membranous, GN which is also seen in China and Thailand. In the 3rd decade, there was a dramatic increase in focal sclerosing glomerulosclerosis. This increase reflects aging and obesity in keeping with more developed countries like Australia, India, Thailand and the United States of America. IgA nephritis remains the most common GN. Apart from the geographical influence, other socioeconomic factors play a significant role in the evolution of the renal biopsy pattern. Mesangial proliferative GN remains prevalent in many Asian countries, but in Singapore the prevalence is decreasing just as it is in Japan, Korea and Malaysia. Worldwide, the prevalence of focal sclerosing glomerulosclerosis continues to increase in many countries.

Beneficial effects of high-dose losartan in IgA nephritis.

AIM: Several short-term studies have reported the efficacy of high-dose ARB in reducing proteinuria in patients with diabetic nephropathy. The benefits of long-term high-dose ARB losartan in IgA nephritis have not been explored. METHOD: This was a 6-year randomized trial in 207 patients with IgA nephritis comparing high-dose ARB (losartan 200 mg/day) with normal dose ARB (losartan 100 mg/day), normal dose ACEI (20 mg/day) and low-dose ACEI (10 mg/day). Multivariate ANOVA was used to test the effect of drug treatment on both eGFR and total urinary protein (TUP). RESULTS: Comparing patients on high-dose ARB (n = 63) with those on normal dose ARB (n = 43), normal dose ACEI (n = 61) and low-dose ACEI (n = 40), patients on high Dose ARB had significantly higher eGFR (p < 0.0005) and lower proteinuria (p < 0.005) at the end of the study. The loss in eGFR was 0.7 ml/min/year for high-dose ARB compared to 3.2 - 3.5 ml/ min/year for the other 3 groups (p = 0.0005). There were more patients on high-dose ARB with improvement in eGFR compared to other 3 groups (p < 0.001). CONCLUSION: Data from this study suggest that high-dose ARB therapy is more efficacious in reducing proteinuria and preserving renal function when compared with normal dose ARB and ACEI. In Year 5, patients on high-dose ARB had a gain in eGFR suggesting that there is possibility of recovery of renal function in these patients on long-term high-dose therapy.

Presence of organochlorine pollutants in fat and scats of pinnipeds from the Antarctic Peninsula and South Shetland Islands, and their relationship to trophic position.

Antarctica is still considered one of the few pristine areas in the globe. Despite this, several studies have shown phased out organic pollutants are present in several environmental abiotic and biological compartments. This study, based on blubber and fecal samples collected from five species of Antarctic pinnipeds, assessed the relationship between organochlorine pesticide (OCs) levels and trophic characterization using stable isotope analysis (δ13C and δ15N). The prevailing pollutants found in blubber were hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), Heptachlor and Aldrin (0.84-564.11 ng g-1 l.w.). We also report a high presence of HCHs, Endrin, Dichlorodiphenyltrichloroethane (DDTs) and Methoxychlor (4.50-363.86 ng g-1 d.w.) in feces suggesting a detoxification mechanism. All the species tend towards high trophic positions (3.4-4.9), but with considerable variation in trophic niche and organochlorine pesticide concentrations per sampling site. This finding suggests that differences in pesticide levels in individuals are associated to foraging ecology.

Quantitative Susceptibility Mapping of the Thalamus: Relationships with Thalamic Volume, Total Gray Matter Volume, and T2 Lesion Burden.

BACKGROUND AND PURPOSE: Both thalamic iron deposition and atrophy have been reported in patients with multiple sclerosis compared with healthy controls, but how they are related is unclear. The purpose of this study was to understand the pathophysiologic basis for this iron deposition. MATERIALS AND METHODS: Ninety-five patients with relapsing-remitting multiple sclerosis underwent 3T MR imaging with a standardized protocol that included quantitative susceptibility mapping to measure iron concentration and a 3D T1 echo-spoiled gradient-echo sequence to obtain thalamic volumes. Volumes of interest were manually delineated on the quantitative susceptibility map to encompass both thalami. Multivariate regression analyses were performed to identify the association between thalamic susceptibility and volume. Associations between thalamic susceptibility and total gray matter volume, cortical thickness, and T2 lesion volume were also assessed. RESULTS: The relative susceptibility of the thalamus was associated with T2 lesion volume (P = .015) and was higher in the presence of enhancing lesions (P = .013). The relative susceptibility of the thalami was not associated with thalamic volumes, total gray matter volumes, or cortical thickness (P > .05). CONCLUSIONS: Iron levels in the thalami are associated with T2 lesion burden and the presence of enhancing lesions, but not with thalamic or gray matter volumes, suggesting that iron accumulation is associated with white matter inflammation rather than gray matter neurodegeneration.

Identification of a binding site in c-Ab1 tyrosine kinase for the C-terminal repeated domain of RNA polymerase II.

The c-abl proto-oncogene encodes a nuclear tyrosine kinase that can phosphorylate the mammalian RNA polymerase II (RNAP II) on its C-terminal repeated domain (CTD) in vitro. Phosphorylation of the CTD has previously been shown to require the tyrosine kinase and the SH2 domain of Abl. We show here that a CTD-interacting domain (CTD-ID) at the C-terminal region of c-Abl is also required. Deletion of the CTD-ID causes the Km 0.4 microM to increase by 2 orders of magnitude. Direct binding of the CTD-ID to CTD and to RNAP II could be demonstrated in vitro. Phosphorylation of a recombinant glutathione S-transferase-CTD by c-Abl was observed in cotransfected COS cells. Mutant Abl proteins lacking the CTD-ID, while capable of autophosphorylation, neither phosphorylated nor associated with the glutathione S-transferase-CTD in vivo. Transient overexpression of c-Abl also led to a four- to fivefold increase in the phosphotyrosine content of the RNAP II large subunit. Moreover, the large subunit of RNAP II could be coprecipitated with c-Abl. Tyrosine phosphorylation of the coprecipitated RNAP II was again dependent on the presence of the CTD-ID in Abl. Finally, the ability of c-Abl to phosphorylate and associate with RNAP II could be correlated with the enhancement of transcription by c-Abl in transient cotransfection assays. Taken together, these observations demonstrate that c-Abl can function as a CTD kinase in vitro as well as in vivo.

Relationships among Cortical Glutathione Levels, Brain Amyloidosis, and Memory in Healthy Older Adults Investigated In Vivo with 1H-MRS and Pittsburgh Compound-B PET.

BACKGROUND AND PURPOSE: Oxidative stress has been implicated as an important pathologic mechanism in the development of Alzheimer disease. The purpose of this study was to assess whether glutathione levels, detected noninvasively with proton MR spectroscopy, are associated with brain amyloidosis and memory in a community-dwelling cohort of healthy older adults. MATERIALS AND METHODS: Fifteen cognitively healthy subjects were prospectively enrolled in this study. All subjects underwent 1H-MR spectroscopy of glutathione, a positron-emission tomography scan with an amyloid tracer, and neuropsychological testing by using the Repeatable Battery for the Assessment of Neuropsychological Status. Associations among glutathione levels, brain amyloidosis, and memory were assessed by using multivariate regression models. RESULTS: Lower glutathione levels were associated with greater brain amyloidosis in the temporal (P = .03) and parietal (P = .05) regions, adjusted for apolipoprotein E ε4 carrier status. There were no significant associations between glutathione levels and cognitive scores. CONCLUSIONS: This study found an association between cortical glutathione levels and brain amyloidosis in healthy older adults, suggesting a potential role for 1H-MR spectroscopy measures of glutathione as a noninvasive biomarker of early Alzheimer disease pathogenesis.

Quantitative Susceptibility Mapping and R2* Measured Changes during White Matter Lesion Development in Multiple Sclerosis: Myelin Breakdown, Myelin Debris Degradation and Removal, and Iron Accumulation.

BACKGROUND AND PURPOSE: Quantitative susceptibility mapping and R2* are sensitive to myelin and iron changes in multiple sclerosis lesions. This study was designed to characterize lesion changes on quantitative susceptibility mapping and R2* at various gadolinium-enhancement stages. MATERIALS AND METHODS: This study included 64 patients with MS with different enhancing patterns in white matter lesions: nodular, shell-like, nonenhancing < 1 year old, and nonenhancing 1-3 years old. These represent acute, late acute, early chronic, and late chronic lesions, respectively. Susceptibility values measured on quantitative susceptibility mapping and R2* values were compared among the 4 lesion types. Their differences were assessed with a generalized estimating equation, controlling for Expanded Disability Status Scale score, age, and disease duration. RESULTS: We analyzed 203 lesions: 80 were nodular-enhancing, of which 77 (96.2%) were isointense on quantitative susceptibility mapping; 33 were shell-enhancing, of which 30 (90.9%) were hyperintense on quantitative susceptibility mapping; and 49 were nonenhancing lesions < 1 year old and 41 were nonenhancing lesions 1-3 years old, all of which were hyperintense on quantitative susceptibility mapping. Their relative susceptibility/R2* values were 0.5 ± 4.4 parts per billion/-5.6 ± 2.9 Hz, 10.2 ± 5.4 parts per billion/-8.0 ± 2.6 Hz, 20.2 ± 7.8 parts per billion/-3.1 ± 2.3 Hz, and 33.2 ± 8.2 parts per billion/-2.0 ± 2.6 Hz, respectively, and were significantly different (P < .005). CONCLUSIONS: Early active MS lesions with nodular enhancement show R2* decrease but no quantitative susceptibility mapping change, reflecting myelin breakdown; late active lesions with peripheral enhancement show R2* decrease and quantitative susceptibility mapping increase in the lesion center, reflecting further degradation and removal of myelin debris; and early or late chronic nonenhancing lesions show both quantitative susceptibility mapping and R2* increase, reflecting iron accumulation.

Magnetic Susceptibility from Quantitative Susceptibility Mapping Can Differentiate New Enhancing from Nonenhancing Multiple Sclerosis Lesions without Gadolinium Injection.

BACKGROUND AND PURPOSE: Magnetic susceptibility values of multiple sclerosis lesions increase as they change from gadolinium-enhancing to nonenhancing. Can susceptibility values measured on quantitative susceptibility mapping without gadolinium injection be used to identify the status of lesion enhancement in surveillance MR imaging used to monitor patients with MS? MATERIALS AND METHODS: In patients who had prior MR imaging and quantitative susceptibility mapping in a current MR imaging, new T2-weighted lesions were evaluated for enhancement on conventional T1-weighted imaging with gadolinium, and their susceptibility values were measured on quantitative susceptibility mapping. Receiver operating characteristic analysis was used to assess the diagnostic accuracy of using quantitative susceptibility mapping in distinguishing new gadolinium-enhancing from new nonenhancing lesions. A generalized estimating equation was used to assess differences in susceptibility values among lesion types. RESULTS: In 54 patients, we identified 86 of 133 new lesions that were gadolinium-enhancing and had relative susceptibility values significantly lower than those of nonenhancing lesions (ß = -17.2; 95% CI, -20.2 to -14.2; P < .0001). Using susceptibility values to discriminate enhancing from nonenhancing lesions, we performed receiver operating characteristic analysis and found that the area under the curve was 0.95 (95% CI, 0.92-0.99). Sensitivity was measured at 88.4%, and specificity, at 91.5%, with a cutoff value of 11.2 parts per billion for quantitative susceptibility mapping-measured susceptibility. CONCLUSIONS: During routine MR imaging monitoring to detect new MS lesion activity, quantitative susceptibility mapping can be used without gadolinium injection for accurate identification of the BBB leakage status in new T2WI lesions.

Examining trends in the treatment of ureterocele yields no definitive solution.

INTRODUCTION: The surgical management of ureteroceles is extremely variable. Some have hypothesized that if these patients were treated with 'definitive' staged surgical intervention, the need for further revision surgery would be eliminated. OBJECTIVE: The present study sought to determine if the rate of revision surgery differed among patients who have undergone different surgical approaches for the ureterocele complex. STUDY DESIGN: A large retrospective chart review was conducted, identifying all patients having undergone ureterocele surgery at a single institution over the past 41 years. The cohort was divided into four groups based on surgical approach: upper tract approach (UTA), lower tract reconstruction (LTR), simultaneous upper and lower tract approach (ULTA), and staged lower tract reconstruction (SLTR). Demographics, the presence of preoperative/postoperative VUR, postoperative morbidity and the need for revision surgery were compared using the Chi- squared test, Fisher's exact test, Kruskal-Wallis test, Mann-Whitney U test (Bonferroni correction), logistic regression modeling and survival analyses (Kaplan-Meier and Cox proportional Hazards regression with unplanned revision operation as the outcome event). RESULTS: Between 1969 and 2010, 180 patients were identified as having undergone surgical management of ureteroceles, of which 120 had complete demographic data available for analysis. The median age at the time of initial surgical intervention was 5.8 months and the majority of patients (83.3%) were female. The median follow-up was 33.1 months. Surgical management was as follows: 18 (15.0%) patients underwent UTA, 47 (39.2%) underwent LTR, 23 (19.2%) underwent ULTA, and 32 (26.6%) underwent SLTR. Among these groups, the only difference in median age was between the LTR and SLTR groups (6.3 months vs 3.7 months, P=0.012). Additional revision surgery was required in: nine (50.0%) of UTA, ten (21.3%) of LTR, four (17.4%) of ULTA, and three (9.4%) of SLTR. The only statistically significant difference in unplanned revision surgery was noted in the UTA group versus each of the other groups with VUR as the predominant indication (88.9%). The likelihood of requiring revision surgery in comparison to the SLTR group was significantly increased in the UTA group (OR 9.67, CI 2.15-43.56), but not in the LTR (OR 2.61, CI 0.66-10.37) or the ULTA group (OR 2.04, CI 0.41-10.13). Obstruction, recurring UTIs and VUR were the main indications for revision surgery overall. DISCUSSION: There is a large body of literature examining the surgical management of ureteroceles. It most recently primarily focuses on an endoscopic approach to the lower tract. The present retrospective review examined the need for re-operative intervention by comparing four different surgical approaches, and found that there is no panacea. Although heminephrectomy (UTA) was a definitive procedure in some patients without reflux at presentation, many who underwent heminephrectomy, went on to require later bladder surgery for either recurrent UTI or persistent reflux. The present study has multiple limitations. Although VUR was an indication for revision surgery in the early part of the series, the current treatment of VUR is not necessarily as stringent. In addition, no distinction was made between an orthotopic or ectopic ureterocele, although some authors have reported differing outcomes in these two groups. However, it is felt that given the large data set of a relatively uncommon condition, the lack of superiority of one approach is apparent. CONCLUSION: There is no definitive surgical repair for the ureterocele complex. All groups except UTA had statistically similar rates of revision surgery. The widespread variability in current management echoes the lack of one superior approach found in this comprehensive series.

Cerebral Microbleeds, CSF p-Tau, and Cognitive Decline: Significance of Anatomic Distribution.

BACKGROUND AND PURPOSE: Cerebral microbleeds are associated with aging, hypertension, and Alzheimer disease. Microbleeds in a lobar distribution are believed to reflect underlying amyloid angiopathy, whereas microbleeds in the deep gray matter and infratentorial brain are commonly seen with hypertension. However, it is unknown how microbleeds in either distribution are related to Alzheimer pathogenesis. The purpose of this analysis was to test whether lobar and deep gray/infratentorial microbleeds demonstrate differential associations with CSF amyloid-ß and phosphorylated tau 181 protein levels and longitudinal cognitive decline. MATERIALS AND METHODS: A total of 626 subjects (151 cognitively normal, 389 with mild cognitive impairment, and 86 with Alzheimer disease) from the Alzheimer's Disease Neuroimaging Initiative who had undergone 3T MR imaging and lumbar puncture were included in the analysis. The number and location of microbleeds were assessed visually. Associations between lobar or deep gray/infratentorial microbleeds with CSF amyloid-ß levels, abnormal CSF phosphorylated tau 181 protein levels, and longitudinal cognitive decline were assessed by using ordinary least-squares, logistic, and mixed-effects regression models while adjusting for covariates. RESULTS: Having ≥3 lobar microbleeds was associated with lower levels of CSF amyloid-ß (P = .001). After adjusting for CSF amyloid-ß level, lobar microbleeds were independently associated with a higher likelihood of having an abnormal CSF phosphorylated tau 181 protein level (P = .004). Lobar microbleeds were associated with accelerated longitudinal cognitive decline (P = .007). Deep gray/infratentorial microbleeds revealed no significant associations. CONCLUSIONS: The distribution of microbleeds revealed different associations with amyloid-ß and phosphorylated tau 181 protein levels and cognition. Lobar and deep gray/infratentorial microbleeds should be considered separately with regard to Alzheimer disease pathogenesis.

Bone marrow stromal cell-mediated gene therapy for hemophilia A: in vitro expression of human factor VIII with high biological activity requires the inclusion of the proteolytic site at amino acid 1648.

To evaluate the potential of the ex vivo bone marrow stromal cell (BMSC) system as a gene therapy for hemophilia A, we studied the in vitro expression of human factor VIII (hFVIII) in canine BMSCs following transfection with plasmid vectors and transduction with retroviral vectors. Vectors were composed of B domain-deleted forms of hFVIII that either retain or delete the proteolytic site at amino acid 1648. On transfection of BMSCs, vectors supported expression and secretion of similar levels of up to 386 mU/10(6) cells/24 hr, even though only 3-9% of the cells expressed hFVIII while 42-48% of transfected cells harbored plasmid vector. Much higher percentages (approximately 70%) of cells expressing hFVIII were achieved when BMSCs were transduced by retroviral vectors, resulting in expression and secretion as high as 1000-4000 mU/10(6) cells/24 hr. Western analysis demonstrated that the B domain-deleted forms possessing the proteolytic site were secreted predominantly as heavy and light chain heterodimers that resemble native forms found in plasma. In contrast, the hFVIII lacking the proteolytic site was expressed mostly as unprocessed, single heavy-light chains. Both hFVIII forms were correctly cleaved and activated by thrombin. The proteolyzed hFVIII form possessed > or = 93% normal biological activity while the unproteolyzed form possessed consistently less than 55% normal biological activity and was therefore considered less suitable for therapeutic application. These results demonstrate that the BMSC system has potential utility in gene therapy for hemophilia A and stress the importance of selecting the appropriate hFVIII structure for prospective clinical use.

Retroviral vector-modified bone marrow stromal cells secrete biologically active factor IX in vitro and transiently deliver therapeutic levels of human factor IX to the plasma of dogs after reinfusion.

Canine bone marrow stromal cells (BMSCs), transduced ex vivo with retroviral vectors, expressed and secreted biologically active human and canine coagulation factor IX (hFIX and cFIX) in vitro, and on autologous reinfusion expressed hFIX into the circulation of normal (nonhemophiliac) dogs. Human FIX, when expressed in vitro by BMSCs of two dogs at 1.22 and 1.39 microg/10(6) cells/24 hr in medium supplemented with vitamin K, respectively, exhibited 28.1 and 27.3% normal biological activity as determined on the basis of a one-stage clotting assay. BMSCs of two additional dogs expressed 1.54 and 4.81 microg of cFIX/10(6) cells/24 hr in vitamin K-supplemented medium and the expressed cFIX possessed 58.4 and 32.9% normal activity, respectively. Between 2.33 and 3.35 x 10(8) transduced BMSCs, expressing 1.22 and 2.61 microg of hFIX/10(6) cells/24 hr or 3.24 and 7.82 microg of cFIX/10(6) cells/24 hr were reintroduced into the four donor dogs by intravenous infusion. Human FIX was detected in plasma for 7 or 12 days after BMSC reinfusion, with peak levels of 85.8 and 233.0 ng/ml observed at 2 days. Canine anti-hFIX antibodies, which were detected as early as 2-4 days after reinfusion of BMSCs expressing hFIX, may have masked potentially longer duration expression in vivo. Peak plasma levels of hFIX represented 2.1 and 5.8% normal human hFIX levels. When adjusted for percent normal one-stage clotting activity determined in vitro, these levels represented 0.6 and 1.6% normal human hFIX activity levels. Thus, we have demonstrated that retroviral vector-modified BMSCs can deliver human therapeutic levels of hFIX to the circulation of dogs.

Molybdenum absorption, excretion, and retention studied with stable isotopes in young men during depletion and repletion.

A study of molybdenum absorption, excretion, and balance was conducted in four young men fed a low-molybdenum diet (22 micrograms/d) for 102 d followed by 18 d of the same diet supplemented to contain 467 micrograms/d. The study was conducted to determine the minimum dietary molybdenum requirement of healthy young men. Stable isotopes of molybdenum were used as tracers. 100Mo was fed four times during the study, 97Mo was infused twice, and 94Mo was used as an isotopic diluent to quantify the molybdenum isotopes and total molybdenum in complete urine and fecal collections and in the diets. The study demonstrated that subjects could not consistently attain balance with the low-molybdenum diet, but balance improved with time, and no signs of molybdenum deficiency were observed. Molybdenum was very efficiently absorbed at both intakes of dietary molybdenum and urinary excretion increased as dietary molybdenum increased. Molybdenum turnover was significantly slower when dietary molybdenum was low. We estimate from these results that the minimum dietary molybdenum requirement is approximately 25 micrograms/d or possibly less. This suggests that the lower end of the recommended range could be less than the current recommended amount of 75 micrograms/d.