Myocardial T2* is not affected by ageing, myocardial fibrosis, or impaired left ventricular function

PURPOSE

To evaluate the influence of alterations in myocardial structure and function from increasing age, myocardial fibrosis, or impaired left ventricular function on myocardial T2*.

MATERIALS AND METHODS

Myocardial T2* was measured in 126 subjects without cardiac iron loading, of whom 63 were normals of varying ages, 39 were patients with impaired left ventricular function from various nonsiderotic cardiac causes, and 24 were patients with chronic myocardial infarction affecting the interventricular septum (where myocardial T2* measurements are normally made).

RESULTS

The median (Q1, Q3) of myocardial T2* in the normals was 36.3 ms (31.6, 45.4). There was no significant correlation between myocardial T2* and age (R(2) = 0.04; P = 0.11). In the patients with impaired left ventricular function, the median myocardial T2* was 35.5 ms (31, 42.2) (P = 0.34 versus normals). There was no significant correlation between ejection fraction and T2* in patients with left ventricular impairment (R(2) = 0.03; P = 0.33). In the patients with septal infarction, the median septal myocardial T2* was 35.4 ms (32.7, 43) (P = 0.81 vs normals).

CONCLUSION

There was no significant change in myocardial T2* associated with any alterations of myocardial structure and function occurring with increasing age, impairment of left ventricular function or septal fibrosis from chronic myocardial infarction. These results indicate that myocardial T2* measurements are robust to these potential confounding parameters.

Fast onset sensitivity relief of a 0.454% stannous fluoride dentifrice

OBJECTIVE

To evaluate the efficacy ofa stannous fluoride dentifrice as compared to a negative control dentifrice in the reduction of dentinal hypersensitivity after immediate use, and after three days and two weeks of use.

METHODS

This was a controlled, randomized, examiner-blind, two-treatment, parallel group study conducted among healthy adult male and female subjects with moderate dentinal hypersensitivity. Subjects with at least two sensitive teeth demonstrating reproducible sensitivity to both thermal stimuli (SchiffAir Sensitivity Scale score of > 1) and tactile stimuli (Yeaple probe 10 grams) were randomized to treatment with either a 0.454% stannous fluoride (SnF,) dentifrice (experimental group) or a 0.76% sodium monofluorophosphate dentifrice (negative control group). At baseline, subjects received an oral soft tissue examination, were assessed for tooth sensitivity, and were instructed, according to manufacturer's product instructions, to brush with their assigned dentifrice thoroughly twice a day (morning and evening). Subjects performed their first product use on site under supervision. Immediately following the first treatment, both examiner and subject assessed sensitivity to thermal stimuli for each enrolled tooth using the Schiff Air Sensitivity Scale and air visual analog scale (VAS), respectively. Thermal sensitivity was also assessed (by both examiner and subject) at the Day 3 and Week 2 study visits, together with tactile sensitivity (Yeaple probe) and oral soft tissue exams of the mouth.

RESULTS

One-hundred and eleven subjects were enrolled and randomized to one of the two treatment groups. Immediately after the first use, the SnF, dentifrice provided statistically significant (p < 0.0001) reductions in sensitivity relative to the negative control dentifrice of 13.8% for the thermal Schiff Air Sensitivity Scale and 14.6% for the air VAS. The SnF, dentifrice also provided statistically significant (p < 0.0001) reductions in sensitivity relative to the negative control at Day 3 and at Week 2 based on the thermal Schiff Air Sensitivity Scale (31.8% and 61.3%, respectively) and the thermal air VAS (34.8% and 66.6%, respectively). For the tactile Yeaple probe, the SnF2 dentifrice demonstrated significantly (p < 0.0001) better sensitivity scores relative to the negative control at Day 3 and Week 2, with improvements of 186% and 239%, respectively. Both dentifrices were well tolerated.

CONCLUSION

An experimental 0.454% SnF2 dentifrice provides significantly better immediate and ongoing sensitivity relief relative to a negative control dentifrice.

A novel xylene substitute for histotechnology and histochemistry

Propylene glycol methyl ether (PGME) exhibits excellent solvent and coupling properties. A toxicity database provided evidence suggesting that PGME might be a useful substitute for xylene in histotechnology and histochemistry applications. Tissue specimens were fixed, cleared in either PGME or xylene, embedded in paraffin wax, then dewaxed in either PGME or xylene. Sections were treated with the following stains: hematoxylin & eosin (H & E), three special stains of the Gordon/Sweet silver staining method, PAS, and Masson's trichrome, and immunostains including actin, CD3, CD34, CK, CK7/CK9, Ki-67, and ER/PR. The sections were mounted in a resinous medium consisting of PGME and pinene copolymer, then examined under a microscope. Variables such as water tolerance, dimension change, organic solvency, and anti-fading efficacy also were assessed. Depending on the application, PGME performance was equal to or exceeded that of xylene. PGME provided better optical clarity and nuclear detail, did not harden the tissue samples, conserved tissue antigenicity, and was amenable to resinous mounting. Tissues not dehydrated with absolute ethanol also were processed properly. Tissues treated with PGME did not warp or contract compared to those treated with xylene (p < 0.0001). PGME, however, exhibited less organic solvency than xylene. There was no discernible change in the colors of stains in sections processed with PGME even after storage for two years. These results suggest that PGME is a novel xylene substitute for applications in histotechnology and histochemistry.

Expansion of CD133(+) colon cancer cultures retaining stem cell properties to enable cancer stem cell target discovery

Background:

Despite earlier studies demonstrating in vitro propagation of solid tumour cancer stem cells (CSCs) as non-adherent tumour spheres, it remains controversial as to whether CSCs can be maintained in vitro. Additional validation of the CSC properties of tumour spheres would support their use as CSC models and provide an opportunity to discover additional CSC cell surface markers to aid in CSC detection and potential elimination.

Methods:

Primary tumour cells isolated from 13 surgically resected colon tumour specimens were propagated using serum-free CSC-selective conditions. The CSC properties of long-term cultured tumour spheres were established and mass spectrometry-based proteomics performed.

Results:

Freshly isolated CD133⁺ colorectal cancer cells gave rise to long-term tumour sphere (or spheroids) cultures maintaining CD133 expression. These spheroid cells were able to self-renew and differentiate into adherent epithelial lineages and recapitulate the phenotype of the original tumour. Relative to their differentiated progeny, tumour spheroid cells were more resistant to the chemotherapeutic irinotecan. Finally, CD44, CD166, CD29, CEACAM5, cadherin 17, and biglycan were identified by mass spectrometry to be enriched in CD133⁺ tumour spheroid cells.

Conclusion:

Our data suggest that ex vivo-expanded colon CSCs isolated from clinical specimens can be maintained in culture enabling the identification of CSC cell surface-associated proteins.

PI3K/Akt promotes GRP78 accumulation and inhibits endoplasmic reticulum stress-induced apoptosis in HEK293 cells

The potential pro-survival role of phosphatidylinositol 3-kinase (PI3K)/Akt during endoplasmic reticulum stress has been well-characterized. However, the detailed mechanisms remain largely unknown. Here, we showed that PI3K/Akt inhibition promoted endoplasmic reticulum stress-induced apoptosis in a glucose-regulated protein 78 (GRP78)-dependent manner. During endoplasmic reticulum stress, high levels of Akt phosphorylation were sustained for at least 18 h in HEK293 cells. Importantly, PI3K/Akt enhanced GRP78 accumulation through increasing its stability following endoplasmic reticulum stress. Furthermore, Akt1, but not Akt2 or Akt3, was involved in GRP78 stability regulation. These results suggest that PI3K/Akt inhibits endoplasmic reticulum stress-induced apoptosis in HEK293 cells, at least in part, by promoting GRP78 protein stability.

Function of beta1 integrin in oral epithelia and tooth bud morphogenesis

Integrin beta1 is critical for basement membrane organization and hair follicle morphogenesis in the skin epidermis; however, less is known about its function in the developing oral epithelium. Since the skin and oral epithelia share structural similarity, we hypothesized that beta1 integrin function would be critical for the normal development of oral epithelium and tooth buds. The conditional (oral mucosa-specific) beta1 integrin knockout (KO) mice displayed severe disruption of the basement membrane of the tongue epithelium and developing tooth buds. Interestingly, unlike the developing hair follicles, early morphological development of the KO molar tooth buds was normal. However, subsequent morphogenetic events, such as cusp formation, cervical loop down-growth, and ameloblast polarization, did not occur normally. Primary KO oral keratinocytes showed defective cell spreading and robust focal adhesions. Our studies indicate that beta1 integrin plays an essential role in the normal development of the oral epithelium and its appendages.

Differences in Ca2+ regulation for high-output Is and low-output Ib motor terminals in Drosophila larvae

We determined whether two classes of Drosophila larval motor terminals with known differences in structure and transmitter release also showed differences in Ca(2+) regulation. Larval motor neurons can be separated into those producing large synaptic boutons (Ib) and those with small boutons (Is). Ib terminals release less transmitter during single action potentials (APs) than Is terminals, but show greater facilitation during high-frequency stimulation. We measured Ca(2+) transients produced by single APs and AP trains after loading the terminals with the dextran-conjugated Ca(2+) indicator Oregon Green 488 BAPTA-1 (OGB-1). The two pairs of Is and Ib terminals innervating muscle fiber 4 and fibers 6 and 7 were examined. The OGB-1 concentrations were measured in order to compare measurements from terminals with similar OGB-1 loading. For single APs, the change in OGB-1 fluorescence (DeltaF/F) in Is boutons was significantly larger than in Ib boutons due to greater Ca(2+) influx per bouton volume. The Is boutons had greater surface area and active zone number per bouton volume than Ib boutons; this could account for the differences in Ca(2+) influx and argues for similar Ca(2+) influx at Is and Ib active zones. As previously reported for the Ib boutons, the distal Is boutons had larger single-AP Ca(2+) transients than proximal ones on muscle fibers 6 and 7, but not on fiber 4. This difference was not due to proximal-distal differences in surface area or active zones per bouton volume and may be due to greater Ca(2+) influx at distal active zones. During AP trains, the Is Ca(2+) transients were larger in amplitude and had longer decay time constants than Ib ones. This can be explained by a slower rate of Ca(2+) extrusion from the Is boutons apparently due to lower plasma membrane Ca(2+) ATPase activity at Is boutons compared to Ib boutons.

Contrasting impacts of pollen and seed dispersal on spatial genetic structure in the bird-pollinated Banksia hookeriana

In plants, pollen- and seed-dispersal distributions are characteristically leptokurtic, with significant consequences for spatial genetic structure and nearest-neighbour mating. However, most studies to date have been on wind- or insect-pollinated species. Here, we assigned paternity to quantify effective pollen dispersal over 9 years of mating, contrasted this to seed dispersal and examined their effects on fine-scale spatial genetic structure, within the bird-pollinated shrub Banksia hookeriana (Proteaceae). We used 163 polymorphic amplified fragment length polymorphism markers to assess genetic structure and pollen dispersal in a spatially discrete population of 112 plants covering 0.56 ha. Spatial autocorrelation analysis detected spatial genetic structure in the smallest distance class of 0-5 m (r=0.025), with no significant structure beyond 8 m. Experimentally quantified seed-dispersal distances for 337 seedlings showed a leptokurtic distribution around a median of 5 m, reaching a distance of 36 m. In marked contrast, patterns of pollen dispersal for 274 seeds departed strikingly from typical near-neighbour pollination, with a distribution largely corresponding to the spatial distribution of plants. We found very high multiple paternity, very low correlated paternity and an equal probability of siring for the 50 closest potential mates. Extensive pollen carryover was demonstrated by multiple siring in 83 of 86 (96.5%) two-seeded fruits. Highly mobile nectar-feeding birds facilitate this promiscuity through observed movements that were effectively random. As the incidence of bird-pollination is markedly greater in the Southwest Australian Floristic Region than elsewhere, our results have broad and novel significance for the evolution and conservation for many species in Gondwanan lineages.

The role of colonic metabolism in lactose intolerance

Lactose maldigestion and intolerance affect a large part of the world population. The underlying factors of lactose intolerance are not fully understood. In this review, the role of colonic metabolism is discussed, i.e. fermentation of lactose by the colonic microbiota, colonic processing of the fermentation metabolites and how these processes would play a role in the pathophysiology of lactose intolerance. We suggest that the balance between the removal and production rate of osmotic-active components (lactose, and intermediate metabolites, e.g. lactate, succinate, etc.) in the colon is a key factor in the development of symptoms. The involvement of the colon may provide the basis for designing new targeted strategies for dietary and clinical management of lactose intolerance.