High percentage of fat intakes, not low fat oxidation, may induce overweight cyclists

AIM

There is a number of people who recreationally or professionally participate in regular physical activity that may contribute to reduce body fat and prevent weight gain. However, there are considerable numbers of the people who have excess body fat in this population. Therefore, this study tested the hypothesis that overweight cyclists may be affected by high level of fat oxidation and/or dietary fat intake.

METHODS

Fourteen male cyclists aged 35-50 years participated in this study. All participants were defined as semi-professional cyclists and assigned to either normal cyclist group (NC, N.=7) or overwieht cyclist group (OC, N.=7) based on %body fat (OC>23%>NC). The participants underwent a maximal effort ergometer test and dietary analysis. Independent t-test and two-way ANOVA with repeated measures were used to analyze data.

RESULTS

There were no differences between NC and OC for age, height, weight, body mass index, and all cardiopulmonary fitness variables at rest and during maximal effort ergometer test. However, this study found that total fat, especially saturated fat intake of OC was significantly higher compared to one of NC (total fat: 110.88±12.98 vs. 53.56±6.94, saturated fat: 36.92±5.98 vs. 16.65±3.41, P<0.05).

CONCLUSION

The higher amount total fat intake, especially saturated fat intake not total calorie intake, may play a major role in body composition in endurance trained population.

Analysis of Antarctic proteobacteria by PCR fingerprinting and screening for antimicrobial secondary metabolites

Fifty-seven proteobacterium species were successfully isolated from soils of Barrientos Island of the Antarctic using 11 different isolation media. Analysis of 16S rDNA sequencing of these isolates showed that they belonged to eight different genera, namely Bradyrhizobium, Sphingomonas, Methylobacterium, Caulobacter, Paracoccus, Ralstonia, Rhizobium, and Staphylococcus. All isolates were studied for capability of producing antimicrobial and antifungal secondary metabolites using high-throughput screening models. Approximately 23 (13/57) and 2% (1/57) of isolates inhibited growth of Candida albicans ATCC 10231(T) and Staphylococcus aureus ATCC 51650(T), respectively. These results indicated that proteobacterium species isolates from Antarctic could serve as potential source of useful bioactive metabolites. Enterobacterial repetitive intergenic consensus (ERIC)-PCR fingerprinting produced nine clusters and 13 single isolates, with a high D value of 0.9248. RAPD fingerprinting produced six clusters and 13 single isolates, with a relatively low D value of 0.7776. ERIC-PCR analysis proved to have better discrimination capability than RAPD analysis and generated better clustering for all proteobacterium species isolates. We conclude that ERIC-PCR is a robust, reliable and rapid molecular typing method for discriminating different genera of proteobacteria.

Loss of balance between T helper type 17 and regulatory T cells in chronic human immunodeficiency virus infection

The aim of this study is to characterize the changes of CD4(+) CD25(high) forkhead box P3 (FoxP3(+) ) regulatory T cells (T(reg) ), interleukin (IL)-17 secreting T helper type 17 (Th17) cell frequencies and the balance of these two subsets in a cohort of chronic human immunodeficiency virus type 1 (HIV-1)-infected patients in China. A total of 115 untreated chronic HIV-infected individuals and 32 healthy donors were recruited in this study. Peripheral blood mononuclear cells were isolated from ethylenediamine tetracetic acid (EDTA) anti-coagulated fresh whole blood and stained to characterize the frequencies of T(reg) and Th17. Of a total 115 patients, 42 individuals including 10 elite controllers were followed-up for more than 1 year, and changes of T(reg) and Th17 frequencies were analysed over time. The continuous loss of Th17 cells was accompanied by a concomitant rise in the frequency of T(reg) cells, resulting in a loss of Th17/T(reg) balance during the progressive HIV infection. Meanwhile, the T(reg) levels, Th17 levels and Th17/T(reg) ratios of the elite controller group were comparable to those of the HIV-1 negative controls in the follow-up study. Additionally, we demonstrated that loss of balance between Th17 and T(reg) is associated with an earlier CD4 T cell decline during the course of HIV infection. Our results indicate that a loss of immune-balance of Th17 to T(reg) during HIV-1 disease progression and the persistence of such an immune-balance in the elite controllers may have a critical role in HIV-1 infection and further shed new light into understanding the pathogenesis of HIV-1.

Structural determinants in the second intracellular loop of the human cannabinoid CB1 receptor mediate selective coupling to G(s) and G(i)

BACKGROUND AND PURPOSE

The cannabinoid CB(1) receptor is primarily thought to be functionally coupled to the G(i) form of G proteins, through which it negatively regulates cAMP accumulation. Here, we investigated the dual coupling properties of CB(1) receptors and characterized the structural determinants that mediate selective coupling to G(s) and G(i).

EXPERIMENTAL APPROACH

A cAMP-response element reporter gene system was employed to quantitatively analyze cAMP change. CB(1)/CB(2) receptor chimeras and site-directed mutagenesis combined with functional assays and computer modelling were used to determine the structural determinants mediating selective coupling to G(s) and G(i).

KEY RESULTS

CB(1) receptors could couple to both G(s)-mediated cAMP accumulation and G(i)-induced activation of ERK1/2 and Ca(2+) mobilization, whereas CB(2) receptors selectively coupled to G(i) and inhibited cAMP production. Using CB(1)/CB(2) chimeric receptors, the second intracellular loop (ICL2) of the CB(1) receptor was identified as primarily responsible for mediating G(s) and G(i) coupling specificity. Furthermore, mutation of Leu-222 in ICL2 to either Ala or Pro switched G protein coupling from G(s) to G(i), while to Ile or Val led to balanced coupling of the mutant receptor with G(s) and G(i) .

CONCLUSIONS AND IMPLICATIONS

The ICL2 of CB(1) receptors and in particular Leu-222, which resides within a highly conserved DRY(X)(5) PL motif, played a critical role in G(s) and G(i) protein coupling and specificity. Our studies provide new insight into the mechanisms governing the coupling of CB(1) receptors to G proteins and cannabinoid-induced tolerance.

Conjugated Poly-P-Phenylene (PPP) From Poly(1,3-Cyclohexadiene) (PCHD) Homo- and Block Copolymers: Controlled Processability and Properties

Conjugated polymers have been used as solid-state materials for a variety of opto-electronic applications. Thus, their processability in a number of device fabrication protocols is an important consideration. In this report, we indicate our results on the synthesis of conjugated poly-p-phenylene (PPP) materials derived from poly(1,3-cyclohexadiene) (PCHD). The precursor PCHD polymers were synthesized by living anionic polymerization to produce homo-and block copolymer configurations with polystyrene. We have used a variety of initiators, solvent, and temperature conditions to determine the right parameters for obtaining narrow MWD polymers. The conditions for polymerization determined the ratio of 1,2 and 1,4 isomers in the microstructure. We then proceeded with conversion to PPP derivatives using a dehydrogenation reaction with chloranil. Our results indicate a systematic conversion to a conjugated polymer with increased solubility and photoluminescence properties. The microstructure, MW and block copolymer composition affecting the processability and conversion properties dramatically.

Prospective phase II study of chemoembolization with drug-eluting beads for hepatic neuroendocrine metastases: Interim analysis

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Background: To evaluate safety and efficacy of transarterial chemoembolization with doxorubicin eluting beads (DEB-TACE) in 30 patients with hepatic neuroendocrine metastases (NET) in a prospective phase II study. We report the interim analysis on 10 patients.

Methods: Patients who met inclusion criteria (NET liver-dominant metastases, ECOG 0-1, treatment naïve) underwent up to 4 DEB-TACE sessions (100-300 micron beads loaded with up to 100mg of doxorubicin) within a 6-month period. Statistical plan included interim analysis of initial 10 patients to assess therapeutic efficacy (defined as objective response≥50%). Tumor response was assessed by MR imaging 1 month after treatment using contrast-enhancement (EASL) and tumor size (RECIST). Safety was assessed by NCI Common Terminology Criteria.

Results: DEB-TACE was successfully performed in 10 patients (22 targeted lesions). Patient characteristics included mean age 65 yrs; ECOG 0/1 (6/4); carcinoid syndrome (n=2); tumor burden range (4-75%), and mean targeted tumor size 4.8 cm (range 1.2-10.2). At one month follow-up (n=9), Grade 3 toxicities consisted of hyperglycemia (n=3), abdominal pain (n=3), fatigue (n=1), biloma (n=1) and elevated ALT (n=1). Note that four patients had Grade 2 bilomas, which occurred in the setting of small lesions (<2cm), diffuse disease with very low tumor burden (near military pattern), and single lesion ≥ 5cm. Tumor response using MR imaging at 1 month-follow-up revealed a mean treated tumor decrease in size of 7% (p=0.03), and a mean decrease in contrast-enhancement of 59% (p<0.0001). Using RECIST, partial response was achieved in 1 patient (11%), whereas 8 patients (89%) had stable disease. Using EASL criteria, 7 patients (78%) had objective tumor response and 2 (12%) had stable disease.

Conclusions: Interim analysis shows therapeutic efficacy of DEB-TACE in liver-dominant NET metastases. Early recommendation suggests DEB-TACE may be best suited for NET patients with multifocal disease or diffuse disease with large tumor burden.

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No significant financial relationships to disclose.