Concentrations of progesterone,follistatin, and follicle-stimulating hormone in peripheral plasma across the estrous cycle and pregnancy in merino ewes that are homozygous or noncarriers of the Booroola gene

The circulating concentrations of progesterone, FSH, and follistatin across the estrous cycle and gestation were compared in Australian merino sheep that were homozygous for the Booroola gene, FecB, or were noncarriers. The Booroola phenotype is due to a point mutation in the bone morphogenetic protein receptor 1B. Progesterone concentrations began to rise earlier and were higher in the Booroola ewes than in the noncarriers on most days of the luteal phase but not during the follicular phase of the cycle. Follistatin concentrations remained unchanged across the estrous cycle in both groups of ewes, with no differences between genotypes. FSH concentrations were higher in Booroola ewes than in noncarrier ewes on most days of the estrous cycle, with a significantly higher and broader peak of FSH around the time of estrus. Progesterone concentrations were significantly higher in early and midgestation in Booroola ewes but were lower toward the end of gestation than those in noncarriers. FSH declined in both groups across gestation, with lower concentrations of FSH in Booroola ewes during midgestation. Follistatin remained unchanged across gestation in Booroola ewes and noncarrier ewes with a twin pregnancy but declined across gestation in noncarrier ewes with a singleton pregnancy. These results suggest that follistatin concentration is not regulated by the FecB gene during the estrous cycle and pregnancy but is influenced by the number of fetuses. However, the FecB gene appears to positively affect both progesterone and FSH during the estrous cycle and across pregnancy, which suggests that bone morphogenetic proteins play an important role in the regulation of both hormones.     

Unmodified calcium concentrations in tumour necrosis factor receptor subtype-mediated apoptotic cell death

Partial bladder outlet obstruction of the rabbit bladder results in a rapid increase in mass characterized by remodeling of the bladder wall.In this study we investigated the effect of partial outlet obstruction on microvessel density and distribution in the bladder wall immunohistochemically using CD31 as a marker for vascular endothelium, and on blood flow using a fluorescent microsphere technique. Transverse sections of bladder wall were examined after 0 (unobstructed), 1, 3, 5, 7, and 14 days of obstruction. The microvasculature of obstructed rabbit bladder mucosa and detrusor smooth muscle apparently increased relative to augmentation of these compartments, while new vessels appeared in the thickening serosa. These vascular changes correlated with results showing that, at 1 week after obstruction, blood flow (ml/min/g tissue) to the mucosa and detrusor was unchanged.Thickening of the serosa, apparent after 1 day of obstruction, began before its vascularization. Then, 1 week post-obstruction, there was significant microvessel formation in the transition region between the detrusor smooth muscle and the increasing serosa; after 2 weeks, the entire serosa was vascularized. The vascularization of the muscle-serosal transition region and then the remaining serosa apparently precedes fibroblast differentiation, providing blood supply and thus metabolic support for this process.All obstructed rabbit bladders in this study were in a state of compensated function based on their weights. Our working hypothesis is that blood flow per unit tissue mass is normal in compensated obstructed bladders, thus allowing for normal contractile function and cellular metabolism. The results of this study indicate the presence of an augmented microvasculature in compensated obstructed rabbit bladders that provides adequate blood perfusion for normal function.     

The use of flow cytometry to study the impact of fluid mechanical stress on Escherichia coli W3110 during continuous cultivation in an agitated bioreactor

Continuous culture fermentations of Escherichia coli W3110 have been carried out at controlled dissolved oxygen levels of 40% and 10% of saturation. Satisfactory and reproducible results were obtained. Agitation speeds of 400 and 1200 rpm at an aeration rate of 1 vvm have been used as well as an aeration rate of 3 vvm at 400 rpm. The upper levels of these variables represent much higher agitation and aeration intensities than those normally used in practical fermentations. The fermentations were monitored by mass spectrometry and optical density, and cell samples were studied by flow cytometry, SEM, and TEM. Protocols were developed so the state of both cell membranes and cell size could be measured by flow cytometry. Under all the conditions of agitation and aeration, flow cytometric analysis indicated that both cell membranes were intact and that a cytoplasmic membrane potential existed; also the cell size did not change, results confirmed by SEM and TEM. There were no detectable changes in off-gas analysis or optical density during the continuous fermentation nor in the cell structure as revealed by SEM or TEM, except at the highest agitation intensity. Under the latter conditions, after 7 h, the outer polysaccharide layer on the cell was stripped away. It is concluded that any changes in biological performance of this E. coli cell line due to variations in agitation or aeration intensity or scale of operation cannot be attributed to fluid dynamic stresses associated with the turbulence generated by impellers or with bursting bubbles.     

Estimating striae of Retzius periodicity nondestructively using partial counts of perikymata

Accurate age estimations for enamel formation and the timing of enamel hypoplasia have traditionally only been available through histological analyses of dental thin sections, which is a difficult and destructive process. However, an association between striae of Retzius periodicity, crucial for accurate aging, and the total number of striae in imbricational enamel has been reported in the literature. This means periodicity can be estimated nondestructively but is reliant on all perikymata being visible along the crown surface. Therefore, crowns with worn or damaged surfaces may not be able to be assessed, potentially limiting sample sizes. We tested this relationship in a modern New Zealand sample and investigated whether reliable associations might be identified using only partial perikymata counts from the cervical half of the crown. Using mandibular canines (n = 11), the distribution of perikymata per decile was recorded using high definition replica surfaces. Thin sections of the same crowns were used to assess periodicity histologically along with striae of Retzius distributions. A strong correlation between total striae numbers and periodicity was also identified in our sample. Furthermore, we report strong correlations that allow periodicity to be estimated from perikymata counts using only 10% of crown height when certain deciles are used. Based on these findings, we propose a simple matrix that can be developed for nondestructively estimating periodicity based on the range of perikymata counts in the sixth to ninth deciles. Am J Phys Anthropol 154:251–258, 2014. © 2014 Wiley Periodicals, Inc.     

Prevalence estimates of chronic kidney disease in Canada: results of a nationally representative survey

Background:

Chronic kidney disease is an important risk factor for death and cardiovascular-related morbidity, but estimates to date of its prevalence in Canada have generally been extrapolated from the prevalence of end-stage renal disease. We used direct measures of kidney function collected from a nationally representative survey population to estimate the prevalence of chronic kidney disease among Canadian adults.

Methods:

We examined data for 3689 adult participants of cycle 1 of the Canadian Health Measures Survey (2007–2009) for the presence of chronic kidney disease. We also calculated the age-standardized prevalence of cardiovascular risk factors by chronic kidney disease group. We cross-tabulated the estimated glomerular filtration rate (eGFR) with albuminuria status.

Results:

The prevalence of chronic kidney disease during the period 2007–2009 was 12.5%, representing about 3 million Canadian adults. The estimated prevalence of stage 3–5 disease was 3.1% (0.73 million adults) and albuminuria 10.3% (2.4 million adults). The prevalence of diabetes, hypertension and hypertriglyceridemia were all significantly higher among adults with chronic kidney disease than among those without it. The prevalence of albuminuria was high, even among those whose eGFR was 90 mL/min per 1.73 m² or greater (10.1%) and those without diabetes or hypertension (9.3%). Awareness of kidney dysfunction among adults with stage 3–5 chronic kidney disease was low (12.0%).

Interpretation:

The prevalence of kidney dysfunction was substantial in the survey population, including individuals without hypertension or diabetes, conditions most likely to prompt screening for kidney dysfunction. These findings highlight the potential for missed opportunities for early intervention and secondary prevention of chronic kidney disease.Chronic kidney disease is defined as the presence of kidney damage or reduced kidney function for more than 3 months and requires either a measured or estimated glomerular filtration rate (eGFR) of less than 60 mL/min per 1.73 m², or the presence of abnormalities in urine sediment, renal imaging or biopsy results.¹ Between 1.3 million and 2.9 million Canadians are estimated to have chronic kidney disease, based on an extrapolation of the prevalence of end-stage renal disease.² In the United States, the 1999–2004 National Health and Nutrition Examination Survey reported a prevalence of 5.0% for stage 1 and 2 disease and 8.1% for stage 3 and 4 disease.^3,4Chronic kidney disease has been identified as a risk factor for death and cardiovascular-related morbidity and is a substantial burden on the health care system.^1,5 Hemodialysis costs the Canadian health care system about $60 000 per patient per year of treatment.¹ The increasing prevalence of chronic kidney disease can be attributed in part to the growing elderly population and to increasing rates of diabetes and hypertension.^1,6,7Albuminuria, which can result from abnormal vascular permeability, atherosclerosis or renal disease, has gained recognition as an independent risk factor for progressive renal dysfunction and adverse cardiovascular outcomes.^8–10 In earlier stages of chronic kidney disease, albuminuria has been shown to be more predictive of renal and cardiovascular events than eGFR.^4,9 This has prompted the call for a new risk stratification for cardiovascular outcomes based on both eGFR and albuminuria.¹¹A recent review advocated screening people for chronic kidney disease if they have hypertension, diabetes, clinically evident cardiovascular disease or a family history of kidney failure or are more than 60 years old.⁴ The Canadian Society of Nephrology published guidelines on the management of chronic kidney disease but did not offer guidance on screening.¹ The Canadian Diabetes Association recommends annual screening with the use of an albumin:creatinine ratio,¹² and the Canadian Hypertension Education Program guideline recommends urinalysis as part of the initial assessment of hypertension.¹³ Screening for chronic kidney disease on the basis of eGFR and albuminuria is not considered to be cost-effective in the general population, among older people or among people with hypertension.¹⁴The objective of our study was to use direct measures (biomarkers) of kidney function to generate nationally representative, population-based prevalence estimates of chronic kidney disease among Canadian adults overall and in clinically relevant groups.     

Myostatin induces cachexia by activating the ubiquitin proteolytic system through an NF-kappaB-independent, FoxO1-dependent mechanism

Myostatin, a transforming growth factor-beta (TGF-beta) super-family member, has been well characterized as a negative regulator of muscle growth and development. Myostatin has been implicated in several forms of muscle wasting including the severe cachexia observed as a result of conditions such as AIDS and liver cirrhosis. Here we show that Myostatin induces cachexia by a mechanism independent of NF-kappaB. Myostatin treatment resulted in a reduction in both myotube number and size in vitro, as well as a loss in body mass in vivo. Furthermore, the expression of the myogenic genes myoD and pax3 was reduced, while NF-kappaB (the p65 subunit) localization and expression remained unchanged. In addition, promoter analysis has confirmed Myostatin inhibition of myoD and pax3. An increase in the expression of genes involved in ubiquitin-mediated proteolysis is observed during many forms of muscle wasting. Hence we analyzed the effect of Myostatin treatment on proteolytic gene expression. The ubiquitin associated genes atrogin-1, MuRF-1, and E214k were upregulated following Myostatin treatment. We analyzed how Myostatin may be signaling to induce cachexia. Myostatin signaling reversed the IGF-1/PI3K/AKT hypertrophy pathway by inhibiting AKT phosphorylation thereby increasing the levels of active FoxO1, allowing for increased expression of atrophy-related genes. Therefore, our results suggest that Myostatin induces cachexia through an NF-kappaB-independent mechanism. Furthermore, increased Myostatin levels appear to antagonize hypertrophy signaling through regulation of the AKT-FoxO1 pathway.     

High-resolution imaging reveals indirect coordination of opposite motors and a role for LIS1 in high-load axonal transport

The specific physiological roles of dynein regulatory factors remain poorly understood as a result of their functional complexity and the interdependence of dynein and kinesin motor activities. We used a novel approach to overcome these challenges, combining acute in vivo inhibition with automated high temporal and spatial resolution particle tracking. Acute dynein inhibition in nonneuronal cells caused an immediate dispersal of diverse forms of cargo, resulting from a sharp decrease in microtubule minus-end run length followed by a gradual decrease in plus-end runs. Acute LIS1 inhibition or LIS1 RNA interference had little effect on lysosomes/late endosomes but severely inhibited axonal transport of large, but not small, vesicular structures. Our acute inhibition results argue against direct mechanical activation of opposite-directed motors and offer a novel approach of potential broad utility in the study of motor protein function in vivo. Our data also reveal a specific but cell type-restricted role for LIS1 in large vesicular transport and provide the first quantitative support for a general role for LIS1 in high-load dynein functions.     

Abrogation of oxidative stress improves insulin sensitivity in the Ren-2 rat model of tissue angiotensin II overexpression

To evaluate the role of renin-angiotensin system (RAS)-mediated oxidative stress in insulin resistance (IR), we compared the effects of the angiotensin II (ANG II) receptor blocker (ARB) valsartan and a superoxide dismutase (SOD) mimetic, tempol, on whole body glucose tolerance and soleus muscle insulin-stimulated glucose uptake in transgenic hypertensive TG(mREN-2)27 (Ren-2) rats. Ren-2 rats and Sprague-Dawley (SD) controls were given valsartan (30 mg/kg) or tempol (1 mmol/l) in their drinking water for 21 days. IR was measured by glucose tolerance testing (1 g/kg glucose ip). IR index (AUC(glucose) x AUC(insulin)) was significantly higher in the Ren-2 animals compared with SD controls (30.5 +/- 7.0 x 10(6) arbitrary units in Ren-2 vs. 10.2 +/- 2.4 x 10(6) in SD, P < 0.01). Both valsartan and tempol treatment normalized Ren-2 IR index. Compared with SD controls (100%), there was a significant increase in superoxide anion production (measured by lucigenin-enhanced chemiluminescence) in soleus muscles of Ren-2 rats (133 +/- 15%). However, superoxide production was reduced in both valsartan- and tempol-treated (85 +/- 22% and 59 +/- 12%, respectively) Ren-2 rats. Insulin (INS)-mediated 2-deoxyglucose (2-DG) uptake (%SD basal levels) was substantially lower in Ren-2 rat soleus muscle compared with SD (Ren-2 + INS = 110 +/- 3% vs. SD + INS = 206 +/- 12%, P < 0.05). However, Ren-2 rats treated with valsartan or tempol exhibited a significant increase in insulin-mediated 2-DG uptake compared with untreated transgenic animals. Improvements in skeletal muscle insulin-dependent glucose uptake and whole body IR in rats overexpressing ANG II by ARB or SOD mimetic indicate that oxidative stress plays an important role in ANG II-mediated insulin resistance.     

Evaluating outcomes of restoration ecology projects on limited budgets: assessment of variation in sampling intensity and sampling frequency for four habitat types

While best practices for evaluating restoration ecology projects are emerging rapidly, budget constraints often limit postrestoration monitoring, which emphasizes the need for practical and efficient monitoring strategies. We examined the postrestoration outcome for an ENGO (Nature Conservancy of Canada) project, to assess retroactively how variation in intensity and frequency of sampling would have affected estimates of plant species composition, diversity, and richness over time. The project restored four habitat types (mesic forest, oak woodland, wet meadow, and sand barren) using sculptured seeding of tallgrass prairie and woody species. Species‐level plant cover was monitored annually for 10 years in 168 2 × 2–m quadrats. We performed randomization tests to examine estimates of species diversity and richness as a function of the number of quadrats sampled, and assessed the necessity of annual sampling for describing changes in species composition and successional trajectories. The randomization tests revealed that sampling 10–17 quadrats, depending on habitat type, was sufficient to obtain estimates of species diversity that were at least 95% of values obtained from the whole dataset. Species richness as a function of number of quadrats sampled did not plateau, which suggests that rather than increasing the number of sampling quadrats, richness could be estimated more efficiently using nonquadrat based sampling techniques. Nonmetric multidimensional scaling analysis revealed that plant species composition largely stabilized by 3–5 years postrestoration depending on habitat type. By that time, native, seeded species dominated the restoration, and the benefits of annual sampling for tracking changes in species composition diminished.     

The inhibition of endocytosis affects HDL-lipid uptake mediated by the human scavenger receptor class B type I

The scavenger receptor SR-BI plays an important role in the hepatic clearance of HDL cholesterol and other lipids, driving reverse cholesterol transport and contributing to protection against atherosclerosis in mouse models. We characterized the role of endocytosis in lipid uptake from HDL, mediated by the human SR-BI, using a variety of approaches to inhibit endocytosis, including hypertonic shock, potassium or energy depletion and disassembly of the actin cytoskeleton. Our studies revealed that unlike mouse SR-BI, human SR-BI-mediated HDL-lipid uptake was reduced by inhibition of endocytosis. This was not dependent on the cytoplasmic C-terminus of SR-BI. Monitoring the uptake of both the protein and lipid components of HDL revealed that although overall lipid uptake was decreased, the degree of selective lipid uptake was increased. These data suggest that that endocytosis is a dynamic regulator of SR-BI's selective lipid uptake activity.