Plaque control evaluation of a stabilized stannous fluoride dentifrice compared to a triclosan dentifrice in a six-week trial

OBJECTIVE

To compare the anti-plaque efficacy of a stabilized 0.454% stannous fluoride (referred to as SnF2) dentifrice versus a 0.3% triclosan dentifrice formulated with a copolymer and sodium fluoride (referred to as triclosan).

METHODS

The study had a randomized, double-blind, two-treatment, parallel-group design, and compared plaque reduction from baseline after both three and six weeks of treatment with either the SnF2 or triclosan dentifrices using a manual toothbrush. Subjects brushed their teeth using their assigned treatment dentifrices according to the manufacturer's instructions. Following overnight plaque accumulation, levels of plaque were assessed by an experienced examiner using the Rustogi, et al. Modified Navy Plaque Index at the start of the study (baseline), and after three and six weeks of regular brushing. Groups were compared using analysis of covariance separately for Weeks 3 and 6, and by repeated measures for Weeks 3 and 6 combined.

RESULTS

One-hundred and twenty subjects were randomized to treatment and 114 subjects completed the study. Both treatment groups showed a statistically significant reduction from baseline in mean plaque values for all three tooth areas (whole mouth, gingival margin, interproximal) at both Weeks 3 and 6 (p < 0.02 for all comparisons). Analysis of covariance showed a statistically significantly (p < 0.0001) lower adjusted mean plaque level for the SnF2 group compared to the triclosan group for all three tooth areas at both Weeks 3 and 6, and for Weeks 3 and 6 combined. Weeks 3 and 6 combined adjusted mean plaque was 36.5% lower for whole mouth for the SnF2 group versus the triclosan group. Weeks 3 and 6 combined adjusted mean plaque reduction from baseline was three times greater for the SnF2 group relative to the triclosan group.

CONCLUSION

Both dentifrices showed statistically significant reductions from baseline in whole mouth, gumline, and interproximal accumulated overnight plaque after three and six weeks of brushing, but the SnF2 dentifrice showed statistically significantly greater plaque reductions versus the triclosan dentifrice.

ABCB1/MDR1 gene polymorphism and colorectal cancer risk: a meta-analysis of case-control studies

AIM

ABCB1/MDR1 protein is found in high concentrations on the apical surfaces of colonic epithelial cells. It acts as an efflux pump by transporting toxic endogenous substances, drugs and xenobiotics out of cells. Polymorphisms in the ABCB1/MDR1 gene may either change expression of the ABCB1/MDR1 protein or alter its function, suggesting its possible association with colorectal cancer. Several studies have reported a relationship between ABCB1 gene polymorphisms and colorectal cancer risk, but no consistent conclusion has been reached. We therefore conducted a meta-analysis to identify any association between the ABCB1 gene and CRC risk.

METHOD

PubMed, Embase, Google Scholar, Cbmdisc and CNKI were searched for studies on the relationship of ABCB1/MDR1 gene SNPs and the incidence of colorectal cancer. Eligible articles were included for data extraction. The main outcome was the frequency of ABCB1/MDR1 gene SNPs among cases and controls. Comparison of the distribution of SNPs was performed mainly using Review Manager 5.0.

RESULTS

Ten, four and two trials were identified that focussed on the ABCB1 gene SNPs rs1045642, rs2032582 and rs3789243, respectively. A total of 3175 cases and 3715 controls were included. The meta-analysis, stratified by ethnicity or population source, indicated no association between the ABCB1 gene rs1045642 polymorphism and colorectal cancer risk. However, when the study by Bae et al. was removed from the analysis, there was some evidence to indicate a higher T-allele frequency in Asian colorectal cancer patients (OR = 1.30, 95% CI: 1.02-1.67, P = 0.03). Neither ABCB1 rs2032582 nor ABCB1 rs3789243 indicated an association with colorectal cancer risk. An increased frequency only of the wild-type combined allele (rs2032582G/rs1045642C) was found in Caucasian patients (OR = 1.22, 95% CI: 1.03-1.44, P = 0.02).

CONCLUSION

There is some evidence to indicate an association between ABCB1 rs1045642T and colorectal cancer risk in Asians. Compared with the ABCB1 gene SNPs rs1045642, rs2032582 or rs3789243 alone, combined haplotypes of several SNPs might be a better marker to determine the genetic influence on the susceptibility to colorectal cancer among Caucasians.

ABCB1/MDR1 gene polymorphism and colorectal cancer risk: a meta-analysis of case-control studies

AIM

ABCB1/MDR1 protein is found in high concentrations on the apical surfaces of colonic epithelial cells. It acts as an efflux pump by transporting toxic endogenous substances, drugs and xenobiotics out of cells. Polymorphisms in the ABCB1/MDR1 gene may either change expression of the ABCB1/MDR1 protein or alter its function, suggesting its possible association with colorectal cancer. Several studies have reported a relationship between ABCB1 gene polymorphisms and colorectal cancer risk, but no consistent conclusion has been reached. We therefore conducted a meta-analysis to identify any association between the ABCB1 gene and CRC risk.

METHOD

PubMed, Embase, Google Scholar, Cbmdisc and CNKI were searched for studies on the relationship of ABCB1/MDR1 gene SNPs and the incidence of colorectal cancer. Eligible articles were included for data extraction. The main outcome was the frequency of ABCB1/MDR1 gene SNPs among cases and controls. Comparison of the distribution of SNPs was performed mainly using Review Manager 5.0.

RESULTS

Ten, four and two trials were identified that focussed on the ABCB1 gene SNPs rs1045642, rs2032582 and rs3789243, respectively. A total of 3175 cases and 3715 controls were included. The meta-analysis, stratified by ethnicity or population source, indicated no association between the ABCB1 gene rs1045642 polymorphism and colorectal cancer risk. However, when the study by Bae et al. was removed from the analysis, there was some evidence to indicate a higher T-allele frequency in Asian colorectal cancer patients (OR = 1.30, 95% CI: 1.02-1.67, P = 0.03). Neither ABCB1 rs2032582 nor ABCB1 rs3789243 indicated an association with colorectal cancer risk. An increased frequency only of the wild-type combined allele (rs2032582G/rs1045642C) was found in Caucasian patients (OR = 1.22, 95% CI: 1.03-1.44, P = 0.02).

CONCLUSION

There is some evidence to indicate an association between ABCB1 rs1045642T and colorectal cancer risk in Asians. Compared with the ABCB1 gene SNPs rs1045642, rs2032582 or rs3789243 alone, combined haplotypes of several SNPs might be a better marker to determine the genetic influence on the susceptibility to colorectal cancer among Caucasians.

Carcass and meat quality traits of four commercial pig crossbreeds in China

We evaluated carcass and meat quality traits of two Chinese native crossbreeds Landrace x Meishan (LM) and Duroc x (Landrace x Meishan) (DLM) and two foreign crossbreeds Duroc x (Landrace x Yorkshire) (DLY) and PIC (an imported five-way crossbreed). One hundred and twenty weaned pigs (half castrated males and half females) were reared and slaughtered at a predestinated slaughter age. The general carcass and meat quality traits were measured and analyzed. The DLY and PIC crosses had significantly heavier live weights (93.39 and 96.33 kg, P < 0.01), significantly higher dressing percentages (80.65 and 79.39%, P < 0.05), significantly bigger loin areas (42.69 and 43.91 cm(2), P < 0.001), and significantly more lean carcasses (65.78 and 66.40%, P < 0.001) than LM and DLM. On the other hand, LM had a significantly lower live weight (70.29 kg, P < 0.01), significantly thicker back fat (3.54 cm, P < 0.001), significantly less lean carcasses (46.82%, P < 0.001), and significantly less ham and breech (26.53%, P < 0.05) than the other crossbreeds. Among meat quality parameters, LM had the highest intramuscular fat content (5.02%, P < 0.001) and the smallest fiber area (3126.45 μm(2), P < 0.01). However, PIC showed the lowest pH(1) (5.82, P < 0.01) and pH(2) (5.63, P < 0.01), the highest drip loss (2.89%, P < 0.01), and the lowest intramuscular fat (1.35%, P < 0.001). We concluded that LM and DLM had good meat quality traits but poorer carcass traits than DLY and PIC; DLY had good carcass and meat quality traits; PIC had good carcass traits, but it had less intramuscular fat, lower pH and higher drip loss.

First Report of Nigrospora oryzae Causing Leaf Spot of Cotton in China

Cotton (Gossypium hirsutum L.) is widely cultivated for the important economic value of the fiber. In the summer of 2011, a leaf spot of cotton plants cv. Wanza40 was observed in 11 fields (total of about 4 ha) in Qianshan County in southwest Anhui Province, China. Approximately 30% of the plants in each field were symptomatic. Affected plants exhibited brown to reddish, irregular foliar lesions, each with a brown border near the vein of the leaves. A sign of fungal infection was a dark leaf mold observed on lesions on the abaxial surface of leaves. Sections of symptomatic leaf tissues were surface-sterilized (in 75% ethanol for 30 s, then 1% NaOCl for 1 min), rinsed three times in sterile distilled water, and plated onto potato dextrose agar (PDA). A fungus consistently recovered from symptomatic leaf samples produced colonies that were initially white and then became grayish brown with the onset of sporulation. Black, spherical to subspherical, single-celled conidia (10 to 12 × 14 to 16 μm) were borne on a hyaline vesicle at the tip of each conidiophore. Morphological characteristics of the fungus were similar to that of Nigrospora oryzae (2). The internal transcribed spacer (ITS) region of ribosomal DNA (rDNA) from a representative strain of the fungus, AHC-1, was amplified using the primers ITS1/ITS4 (4) and sequenced (GenBank Accession No. JQ864579). The ITS sequence had 99% identity with >553 bp of the ITS sequence of an N. oryzae isolate (GenBank Accession No. EU918714.1). On the basis of morphological data and ITS rDNA sequence, the isolate was determined to be N. oryzae. A pathogenicity test was performed on detached, young leaves of 4-month-old healthy cotton plants of cv. Wanza40. Six leaves were inoculated by placing a colonized agar piece (5 mm in diameter) from 7-day-old cultures of the fungus on pushpin-wounded leaves. Another six leaves treated with sterile PDA plugs served as a negative control treatment. Leaves were incubated in petri dishes and maintained at 25°C in a growth chamber programmed for 12 hours of fluorescent white light/day. After 5 days, brown to black lesions were observed on all inoculated leaves, whereas no symptoms developed on control leaves. N. oryzae was consistently reisolated from symptomatic leaves but not from the control leaves. N. oryzae is a weak pathogen on a wide range of plants, and has been described as the causal agent of lint rot on cotton (1,3), but to our knowledge this is the first report of N. oryzae causing a leaf spot of cotton in China. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA, Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , April 8, 2012. (2) H. J. Hudson. Trans. Br. Mycol. Soc. 46:355, 1963. (3) A. J. Palmatter et al. Plant Dis. 87:873, 2003. (4) T. J. White et al. In: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

Physical origin of general oscillation of structure, surface energy, and electronic property in rutile TiO2 nanoslab

Titanium oxide (TiO(2)) nanostructures have been attracting consistent focus in the past few years because of their enhanced power in solar-energy conversion. Surface and interface play a crucial role in the determination of thermodynamic stability and electronic structure of TiO(2) nanostructures. The rutile (110) nanoslab (NS) has been used as a common subject to investigate the surface relaxation, defect characters, molecule adsorption, and chemically dynamic reaction of TiO(2) nanostructures. Up to date, a long-time standing issue in TiO(2) NS, i.e., the general oscillation of structure, surface energy and electronic property with changing of NS thickness, has not been clear. We have presented a comprehensive investigation on the relationship between surface and oscillation behavior in the TiO(2) (110) NS by the first-principles calculations accompanied with the wave function analysis. We clearly, for the first time, pointed out that the dipoles and surface states bonding induced by the surface-surface interactions are the physical origin of general oscillations in the TiO(2) (110) NS. Our findings not only have a new insight into the basic interactions between surfaces in TiO(2) nanostructures, but also provide useful information for tuning the photocatalytic and photovoltaic properties by surface design.

Genetic diversity analysis of barley landraces and cultivars in the Shanghai region of China

We analyzed the genetic diversity of 115 barley germplasms, including 112 landraces and three new barley cultivars grown in the Shanghai region, using a set of 11 SSR markers. Sixty-six alleles were observed at the 11 SSR loci, ranged from three to ten, with a mean of six alleles per locus. The polymorphism information content ranged from 0.568 to 0.853, with a mean of 0.732, indicating considerable genetic variation in barley in the Shanghai area. Clustering analysis indicated that these barley accessions could be divided into two categories (A and B). Ninety-seven six-rowed barley cultivars were classified in the A category; sixteen two-rowed and two six-rowed barley cultivars were classified in the B category. This demonstrated genetic differences between two-rowed and six-rowed barley varieties. In addition, we found that the three new barley cultivars are closely related.

An all-purpose building block: B12N12 fullerene

We have theoretically shown that the boron nitride fullerene cage B(12)N(12) is an all-purpose building block for fabricating multifarious BN nanotubes. Firstly, we investigated the stability and structural of the boron nitride fullerene cage B(12)N(12) and the polymerized derivatives obtained from it. Interestingly we found out that two B(12)N(12) cages can spontaneously form one BN nanotube with two closed ends through the structural transformation when one cage meets another. These results indicated that the fullerene B(12)N(12) can be polymerized to build various remarkable polymers through the spontaneous structural transformation when they are together, which all have planer or tridimensional shapes with a hollow tubular structure, even at the juncture of the coalesced B(12)N(12). Simultaneously, after the structure optimization, the quadrangles at the juncture of the coalesced B(12)N(12) disappear to form a perfect surface only composed of hexagons. Then, we calculated the energy of all the considered nanostructures. The polymerization of the fullerene B(12)N(12) is exothermic and thus can form very stable derivative polymers. These theoretical conclusions stimulate us to use the fullerene B(12)N(12) as an all-purpose building block to construct various BN nanostructures for purpose of fundamental research and potential applications.

Secular trends in the prevalence of general and abdominal obesity among Chinese adults, 1993-2009

The objective of this study is to examine the trends in body mass index (BMI), waist circumference (WC) and prevalence of overweight (BMI 25-27.49 kg m(-2) ), general obesity (BMI ≥ 27.5 kg m(-2) ) and abdominal obesity (WC ≥ 90 cm for men and ≥80 cm for women) among Chinese adults from 1993 to 2009. Data were obtained from the China Health and Nutrition Survey, which was conducted from 1993 to 2009 and included a total of 52,621 Chinese adults. During the period of 1993-2009, mean BMI values increased by 1.6 kg m(-2) among men and 0.8 kg m(-2) among women; mean WC values increased by 7.0 cm among men and 4.7 cm among women. The prevalence of overweight increased from 8.0 to 17.1% among men (P < 0.001) and from 10.7 to 14.4% among women (P < 0.001); the prevalence of general obesity increased from 2.9 to 11.4% among men (P < 0.001) and from 5.0 to 10.1% among women (P < 0.001); the prevalence of abdominal obesity increased from 8.5 to 27.8% among men (P < 0.001) and from 27.8 to 45.9% among women (P < 0.001). Similar significant trends were observed in nearly all age groups and regions for both men and women. The prevalence of overweight, general obesity and abdominal obesity among Chinese adults has increased greatly during the past 17 years.

Sequence variation and genetic diversity in the giant panda

About 336-444 bp mitochondrial D-loop region and tRNA gene were sequenced for 40 individuals of the giant panda which were collected from Mabian, Meigu, Yuexi, Baoxing, Pingwu, Qingchuan, Nanping and Baishuijiang, respectively. 9 haplotypes were found in 21 founders. The results showed that the giant panda has low genetic variations, and that there is no notable genetic isolation among geographical populations. The ancestor of the living giant panda population perhaps appeared in the late Pleistocene, and unfortunately, might have suffered bottleneck attacks. Afterwards, its genetic diversity seemed to recover to some extent.

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.

Effects of yogurt and bifidobacteria supplementation on the colonic microbiota in lactose-intolerant subjects

AIMS

Colonic metabolism of lactose may play a role in lactose intolerance. We investigated whether a 2-week supplementation of Bifidobacterium longum (in capsules) and a yogurt enriched with Bifidobacterium animalis could modify the composition and metabolic activities of the colonic microbiota in 11 Chinese lactose-intolerant subjects.

METHODS AND RESULTS

The numbers of total cells, total bacteria and the Eubacterium rectale/Clostridium coccoides group in faeces as measured with fluorescent in situ hybridization and the faecal beta-galactosidase activity increased significantly during supplementation. The number of Bifidobacterium showed a tendency to increase during and after supplementation. With PCR-denaturing gradient gel electrophoresis, in subjects in which B. animalis and B. longum were not detected before supplementation, both strains were present in faeces during supplementation, but disappeared after supplementation. The degree of lactose digestion in the small intestine and the oro-caecal transit time were not different before and after supplementation, whereas symptom scores after lactose challenge decreased after supplementation.

CONCLUSIONS

The results suggest that supplementation modifies the amount and metabolic activities of the colonic microbiota and alleviates symptoms in lactose-intolerant subjects. The changes in the colonic microbiota might be among the factors modified by the supplementation which lead to the alleviation of lactose intolerance.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides evidence for the possibility of managing lactose intolerance with dietary lactose (yogurt) and probiotics via modulating the colonic microbiota.

Effect of lactose on oro-cecal transit in lactose digesters and maldigesters

BACKGROUND

The transit time of the small intestine, in addition to lactase activity, may influence lactose digestion and thus play a role in the occurrence of lactose intolerance. The objectives of this study were to investigate the effect of lactose on the oro-cecal transit time (OCTT) in lactose digesters and maldigesters as well as the possible mechanisms underlying these effects.

MATERIALS AND METHODS

Twenty-eight Chinese subjects and 16 Dutch subjects underwent one glucose and one lactose challenge in two single-blinded tests. Twenty of the Chinese subjects without complaints after the challenge then underwent another lactose challenge. A 6-h symptom score (SSC) was recorded, breath-hydrogen concentration was measured and OCTT after consumption of glucose and lactose was determined with the lactose-[13C] ureide breath test. The lactose digestion index (LDI) was determined in both the Dutch and 20 Chinese subjects with the 13C/2H-glucose test.

RESULTS

Lactose digesters (n = 13) and maldigesters (n = 20) were classified based on the results of the LDI and the breath-hydrogen test. The OCTT after the lactose and glucose challenges did not differ in the digesters, whereas in the maldigesters the OCTT, after the lactose challenge, was shorter than that after glucose. There was no difference in OCTT after the glucose challenge between the maldigesters and the digesters. However, the OCTT after the lactose challenge in the maldigesters was shorter than that in the digesters. The LDI of the digesters was significantly higher than that of the maldigesters. The OCTT after the lactose challenge was not correlated to the LDI in the maldigesters nor in the digesters. Based on the SSC after the one glucose and two lactose challenges, a tolerant (n = 7) and an intolerant (n = 5) group were classified in the Chinese subjects. The two groups did not differ in their LDI or OCTT after the lactose challenge. The OCTT after the lactose challenge was not correlated to the SSC or the LDI.

CONCLUSIONS

Lactose triggers a faster oro-cecal transit in lactose maldigesters, but not in digesters. However, this could not be explained by intestinal distension resulting from the osmotic load posed by maldigested lactose, and thus suggests a direct effect of lactose on intrinsic factors regulating intestinal motility.

Naloxone and epinephrine are equally effective for cardiopulmonary resuscitation in a rat asphyxia model

BACKGROUND

It is not known whether naloxone is as efficacious as epinephrine during cardiopulmonary resuscitation (CPR). The aim of the study was to compare the effects of naloxone and epinephrine on the outcomes of CPR following asphyxial cardiac arrest in rats.

METHODS

Cardiac arrest was induced with asphyxia by clamping the tracheal tubes. Twenty-four Sprague-Dawley rats were randomized prospectively into a saline group (treated with normal saline, 1 ml intravenously, n = 8), an epinephrine group (treated with epinephrine, 0.04 mg/kg intravenously, n = 8) or a naloxone group (treated with naloxone, 1 mg/kg intravenously, n = 8) in a blind fashion during resuscitation after asphyxial cardiac arrest. After 5 min of untreated cardiac arrest, conventional manual CPR was started and each drug was administered at the same time.

RESULTS

The rates of restoration of spontaneous circulation (ROSC) were one of eight (12.5%), seven of eight (87.5%) and seven of eight (87.5%) in the saline, epinephrine and naloxone groups, respectively. The rates of ROSC in the epinephrine and naloxone groups were equal and significantly greater than that in the saline group (P = 0.01 and P = 0.01, respectively).

CONCLUSION

The administration of naloxone or epinephrine alone may increase the resuscitation rate, and both drugs are equally effective for CPR in a rat asphyxia model. However, the mechanism by which naloxone produces its efficacy during CPR remains unclear and further experimentation will be necessary.